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Sample records for depressed eruption rate

  1. Depressed eruption rate of the rat maxillary incisor in a drug-induced uncompensated hemolytic state model

    SciTech Connect

    Giglio, M.J.; Sanz, A.M.; Bozzini, C.E. )

    1990-03-01

    Female rats weighing about 180 g were separated into two groups. One group (A) received phenylhydrazine (PHZ) every other day during three weeks (for induction of an uncompensated hemolytic state), while the control group (C) received saline. The evidence for the establishment of the uncompensated hemolytic state was obtained by hematocrit value, reticulocyte count, and red-cell-volume-59Fe uptake. Body-weight gain (which is a measure of overall body growth rate), body-length gain (which is a measure of longitudinal skeletal growth rate), food intake, and maxillary incisor eruption rate (ER) were significantly depressed in rats of group A during the PHZ-injection period, in relation to rats of group C. These results indicate that anemia and/or associated factors depress ER, along with body growth and skeletal growth.

  2. Eruption rates in explosive eruptions: Ground truth and models

    NASA Astrophysics Data System (ADS)

    Tumi Gudmundsson, Magnus; Durig, Tobias; Höskuldsson, Ármann; Thordarson, Thorvaldur; Larsen, Gudrún; Óladóttir, Bergrún A.; Högnadóttir, Thórdís; Oddsson, Björn; Björnsson, Halldór; Gudmundsdóttir, Esther R.

    2015-04-01

    Estimations of eruption rates in explosive eruptions are difficult and error margins are invariably high. In small to moderate sized eruptions effects of wind on plume height can be large and in larger eruptions observations are often difficult due to masking of source by low cloud, pyroclastic density currents and monitoring system saturation. Several medium-sized explosive eruptions in recent years have been an important in sparking off intense research on e.g. atmosphere-plume interaction and associated effects of wind on plume height. Other methods that do not rely on plume height are e.g. infrared satellite monitoring of atmospheric loading of fine tephra, infrasound, analysis of video recordings from vents, and it has been suggested that co-eruptive tilt-meter deformation data can predict eruption intensity. The eruptions of Eyjafjallajökull in 2010 and Grímsvötn in 2011 provided a wealth of data that potentially can be of use in developing constraints of eruption rates in explosive eruptions. A key parameter in all such comparisons between models and data is as detailed knowledge as possible on tephra fallout. For both Eyjafjallajökull and Grímsvötn intensive field efforts took place to map out the deposits during and immediately after the eruptions. The resulting maps cover both individual phases as well as total fallout. Comparison of these data with plume-based and other models of mass discharge rates is presently work in progress. A desirable future aim is near real time estimates of mass eruption rates based several of the parameters mentioned above. This type of work is currently ongoing within the framework of the EU-funded supersite project FUTUREVOLC.

  3. Large, Moderate or Small? The Challenge of Measuring Mass Eruption Rates in Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, M. T.; Dürig, T.; Hognadottir, T.; Hoskuldsson, A.; Bjornsson, H.; Barsotti, S.; Petersen, G. N.; Thordarson, T.; Pedersen, G. B.; Riishuus, M. S.

    2015-12-01

    The potential impact of a volcanic eruption is highly dependent on its eruption rate. In explosive eruptions ash may pose an aviation hazard that can extend several thousand kilometers away from the volcano. Models of ash dispersion depend on estimates of the volcanic source, but such estimates are prone to high error margins. Recent explosive eruptions, including the 2010 eruption of Eyjafjallajökull in Iceland, have provided a wealth of data that can help in narrowing these error margins. Within the EU-funded FUTUREVOLC project, a multi-parameter system is currently under development, based on an array of ground and satellite-based sensors and models to estimate mass eruption rates in explosive eruptions in near-real time. Effusive eruptions are usually considered less of a hazard as lava flows travel slower than eruption clouds and affect smaller areas. However, major effusive eruptions can release large amounts of SO2 into the atmosphere, causing regional pollution. In very large effusive eruptions, hemispheric cooling and continent-scale pollution can occur, as happened in the Laki eruption in 1783 AD. The Bárdarbunga-Holuhraun eruption in 2014-15 was the largest effusive event in Iceland since Laki and at times caused high concentrations of SO2. As a result civil protection authorities had to issue warnings to the public. Harmful gas concentrations repeatedly persisted for many hours at a time in towns and villages at distances out to 100-150 km from the vents. As gas fluxes scale with lava fluxes, monitoring of eruption rates is therefore of major importance to constrain not only lava but also volcanic gas emissions. This requires repeated measurements of lava area and thickness. However, most mapping methods are problematic once lava flows become very large. Satellite data on thermal emissions from eruptions have been used with success to estimate eruption rate. SAR satellite data holds potential in delivering lava volume and eruption rate estimates

  4. Estimates of mass eruption rates in Icelandic eruptions 1913-2015

    NASA Astrophysics Data System (ADS)

    Tumi Gudmundsson, Magnus; Dürig, Tobias; Larsen, Gudrún

    2016-04-01

    In the period from 1913 to 2015 about 35 eruptions occurred in Iceland, although some uncertainty exists about the number of the smallest events, particularly within the ice covered regions. For the smaller events in the earlier part of the period, only order of magnitude estimates of mass eruption rates (MER) are possible, based on the approximate amount of erupted products, duration of eruption, and information on eruption plume height in some cases. After 1947 estimates are more reliable. This is not least due to the detailed observations and interpretations of Sigurdur Thorarinsson and co-workers until the early 1980s. After 1980, various observations and instrumental data, e.g. on plume height, coupled with detailed mapping by several workers of tephra fallout and lava flow extent provide a good basis for MER estimates. The most frequent events are explosive eruptions producing tephra, often basaltic phreatomagmatic eruptions. A contributing factor to the large number of explosive eruptions is unusually frequent eruptions in Hekla since 1947. Eruptions under glaciers are also common, while a majority of these become explosive as they break through the ice. For the initially subglacial eruptions ice melting rates provide the best estimate of the MER in the first and usually most powerful phase. If the whole data set is considered, the magma volumes erupted in a single eruption span three orders of magnitude, ˜0.001 km3 to 1 km3. The range of intensity is similar, with the smallest Krafla or Askja events having maximum mass eruption rates (MER) of order 10-100 tonnes/second while the most powerful ones (Hekla 1947 and Katla 1918) had MER ˜50,000 tonnes/second (˜5 x 107 kg/s). All the events with the highest MER were explosive, including Katla 1918 where initial subglacial melting caused the largest volcanogenic flood observed since the 18th century. The period 1913-2015 had no events that belong to the class of the largest observed eruptions in Iceland. In

  5. The influence of magma supply rate on eruption style and textures of erupted ash particles

    NASA Astrophysics Data System (ADS)

    Wright, H. M.; Cashman, K. V.

    2011-12-01

    Persistent low- to moderate-level eruptive activity of basaltic to andesitic volcanoes is difficult to monitor because small changes in magma supply rates can cause abrupt transitions in eruption style. Direct measurement of magma ascent rate is not possible; therefore, we must develop indirect measures of ascent rate. Here, we use a petrologic approach to this problem. We quantify textural variations in Vulcanian and Strombolian eruptive products (erupted between 1999-2006) from Tungurahua volcano, Ecuador. We compare average crystallinities of pyroclasts from a succession of ash eruptions with magma supply rates determined using satellite observations of plume heights and seismic recordings of explosion frequency. We show that tephra crystallinity correlates inversely with magma supply rate, similar to correlations described from decompression experiments of intermediate composition magma. We further suggest that the range of textures present in any individual sample indicates recycling from one eruption to the next and/or simultaneous eruption of particles with different crystallization histories. The correlation between crystallinity and magma supply rate is most easily explained by efficient degassing at very low pressures and degassing-driven crystallization between eruptions. A similar correlation has been shown at Crater Peak, USA (Gardner et al. 1998); Merapi, Indonesia (Hammer et al. 2000); Unzen, Japan (Nakada and Motomura, 1999); and Sakurajima, Japan (Miwa et al., 2009). Futhermore, systematic changes in crystallinity have been shown to extend across a range of eruption styles (including Vulcanian and Strombolian), as at Etna, Italy (Taddeucci et al. 2002) and Croscat, Spain (Cimarelli et al., 2010). This variation with eruption style suggests that the observed transition from intermittent Vulcanian explosions to more continuous periods of Strombolian eruptions and lava fountains can be explained simply by changes in the average crystal content of the

  6. Estimation of Eruption Source Parameters from Plume Growth Rate

    NASA Astrophysics Data System (ADS)

    Pouget, Solene; Bursik, Marcus; Webley, Peter; Dehn, Jon; Pavalonis, Michael; Singh, Tarunraj; Singla, Puneet; Patra, Abani; Pitman, Bruce; Stefanescu, Ramona; Madankan, Reza; Morton, Donald; Jones, Matthew

    2013-04-01

    The eruption of Eyjafjallajokull, Iceland in April and May, 2010, brought to light the hazards of airborne volcanic ash and the importance of Volcanic Ash Transport and Dispersion models (VATD) to estimate the concentration of ash with time. These models require Eruption Source Parameters (ESP) as input, which typically include information about the plume height, the mass eruption rate, the duration of the eruption and the particle size distribution. However much of the time these ESP are unknown or poorly known a priori. We show that the mass eruption rate can be estimated from the downwind plume or umbrella cloud growth rate. A simple version of the continuity equation can be applied to the growth of either an umbrella cloud or the downwind plume. The continuity equation coupled with the momentum equation using only inertial and gravitational terms provides another model. Numerical modeling or scaling relationships can be used, as necessary, to provide values for unknown or unavailable parameters. Use of these models applied to data on plume geometry provided by satellite imagery allows for direct estimation of plume volumetric and mass growth with time. To test our methodology, we compared our results with five well-studied and well-characterized historical eruptions: Mount St. Helens, 1980; Pinatubo, 1991, Redoubt, 1990; Hekla, 2000 and Eyjafjallajokull, 2010. These tests show that the methodologies yield results comparable to or better than currently accepted methodologies of ESP estimation. We then applied the methodology to umbrella clouds produced by the eruptions of Okmok, 12 July 2008, and Sarychev Peak, 12 June 2009, and to the downwind plume produced by the eruptions of Hekla, 2000; Kliuchevsko'i, 1 October 1994; Kasatochi 7-8 August 2008 and Bezymianny, 1 September 2012. The new methods allow a fast, remote assessment of the mass eruption rate, even for remote volcanoes. They thus provide an additional path to estimation of the ESP and the forecasting

  7. Long-Term Volumetric Eruption Rates and Magma Budgets

    SciTech Connect

    Scott M. White Dept. Geological Sciences University of South Carolina Columbia, SC 29208; Joy A. Crisp Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109; Frank J. Spera Dept. Earth Science University of California, Santa Barbara Santa Barbara, CA 93106

    2005-01-01

    A global compilation of 170 time-averaged volumetric volcanic output rates (Qe) is evaluated in terms of composition and petrotectonic setting to advance the understanding of long-term rates of magma generation and eruption on Earth. Repose periods between successive eruptions at a given site and intrusive:extrusive ratios were compiled for selected volcanic centers where long-term (>104 years) data were available. More silicic compositions, rhyolites and andesites, have a more limited range of eruption rates than basalts. Even when high Qe values contributed by flood basalts (9 ± 2 Å~ 10-1 km3/yr) are removed, there is a trend in decreasing average Qe with lava composition from basaltic eruptions (2.6 ± 1.0 Å~ 10-2 km3/yr) to andesites (2.3 ± 0.8 Å~ 10-3 km3/yr) and rhyolites (4.0 ± 1.4 Å~ 10-3 km3/yr). This trend is also seen in the difference between oceanic and continental settings, as eruptions on oceanic crust tend to be predominately basaltic. All of the volcanoes occurring in oceanic settings fail to have statistically different mean Qe and have an overall average of 2.8 ± 0.4 Å~ 10-2 km3/yr, excluding flood basalts. Likewise, all of the volcanoes on continental crust also fail to have statistically different mean Qe and have an overall average of 4.4 ± 0.8 Å~ 10-3 km3/yr. Flood basalts also form a distinctive class with an average Qe nearly two orders of magnitude higher than any other class. However, we have found no systematic evidence linking increased intrusive:extrusive ratios with lower volcanic rates. A simple heat balance analysis suggests that the preponderance of volcanic systems must be open magmatic systems with respect to heat and matter transport in order to maintain eruptible magma at shallow depth throughout the observed lifetime of the volcano. The empirical upper limit of Å`10-2 km3/yr for magma eruption rate in systems with relatively high intrusive:extrusive ratios may be a consequence of the fundamental parameters

  8. Estimating rates of decompression from textures of erupted ash particles produced by 1999-2006 eruptions of Tungurahua volcano, Ecuador

    USGS Publications Warehouse

    Wright, Heather M.N.; Cashman, Katharine V.; Mothes, Patricia A.; Hall, Minard L.; Ruiz, Andrés Gorki; Le Pennec, Jean-Luc

    2012-01-01

    Persistent low- to moderate-level eruptive activity of andesitic volcanoes is difficult to monitor because small changes in magma supply rates may cause abrupt transitions in eruptive style. As direct measurement of magma supply is not possible, robust techniques for indirect measurements must be developed. Here we demonstrate that crystal textures of ash particles from 1999 to 2006 Vulcanian and Strombolian eruptions of Tungurahua volcano, Ecuador, provide quantitative information about the dynamics of magma ascent and eruption that is difficult to obtain from other monitoring approaches. We show that the crystallinity of erupted ash particles is controlled by the magma supply rate (MSR); ash erupted during periods of high magma supply is substantially less crystalline than during periods of low magma supply. This correlation is most easily explained by efficient degassing at very low pressures (<<50 MPa) and degassing-driven crystallization controlled by the time available prior to eruption. Our data also suggest that the observed transition from intermittent Vulcanian explosions at low MSR to more continuous periods of Strombolian eruptions and lava fountains at high MSR can be explained by the rise of bubbles through (Strombolian) or trapping of bubbles beneath (Vulcanian) vent-capping, variably viscous (and crystalline) magma.

  9. Power Outputs and Volumetric Eruption Rates for Ionian Volcanoes from Galileo-NIMS Data

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2001-01-01

    Volumetric eruption rates for a number of Io volcanoes are calculated as a function of volcanic thermal output. Thermal output is determined using 2-temperature fits to NIMS data. Typical eruption rates are larger than terrestrial eruptions of similar style. Additional information is contained in the original extended abstract.

  10. Rate of Forgetting in Dementia and Depression.

    ERIC Educational Resources Information Center

    Hart, Robert P.; And Others

    1987-01-01

    Examined patients (N=14) with mild Alzheimer's dementia (DAT), patients with major depression (N=10), and normal control subjects (N=14), for rate of forgetting. Suggests that some form of deficient consolidation contributes to memory loss in DAT but not in depression. Implicates the disruption of different psychobiological mechanisms in these…

  11. Magma decompression rates during explosive eruptions of Kīlauea volcano, Hawaii, recorded by melt embayments

    NASA Astrophysics Data System (ADS)

    Ferguson, David J.; Gonnermann, Helge M.; Ruprecht, Philipp; Plank, Terry; Hauri, Erik H.; Houghton, Bruce F.; Swanson, Donald A.

    2016-10-01

    The decompression rate of magma as it ascends during volcanic eruptions is an important but poorly constrained parameter that controls many of the processes that influence eruptive behavior. In this study, we quantify decompression rates for basaltic magmas using volatile diffusion in olivine-hosted melt tubes (embayments) for three contrasting eruptions of Kīlauea volcano, Hawaii. Incomplete exsolution of H2O, CO2, and S from the embayment melts during eruptive ascent creates diffusion profiles that can be measured using microanalytical techniques, and then modeled to infer the average decompression rate. We obtain average rates of ~0.05-0.45 MPa s-1 for eruptions ranging from Hawaiian style fountains to basaltic subplinian, with the more intense eruptions having higher rates. The ascent timescales for these magmas vary from around ~5 to ~36 min from depths of ~2 to ~4 km, respectively. Decompression-exsolution models based on the embayment data also allow for an estimate of the mass fraction of pre-existing exsolved volatiles within the magma body. In the eruptions studied, this varies from 0.1 to 3.2 wt% but does not appear to be the key control on eruptive intensity. Our results do not support a direct link between the concentration of pre-eruptive volatiles and eruptive intensity; rather, they suggest that for these eruptions, decompression rates are proportional to independent estimates of mass discharge rate. Although the intensity of eruptions is defined by the discharge rate, based on the currently available dataset of embayment analyses, it does not appear to scale linearly with average decompression rate. This study demonstrates the utility of the embayment method for providing quantitative constraints on magma ascent during explosive basaltic eruptions.

  12. Merapi 2010 eruption-Chronology and extrusion rates monitored with satellite radar and used in eruption forecasting

    NASA Astrophysics Data System (ADS)

    Pallister, John S.; Schneider, David J.; Griswold, Julia P.; Keeler, Ronald H.; Burton, William C.; Noyles, Christopher; Newhall, Christopher G.; Ratdomopurbo, Antonius

    2013-07-01

    Despite dense cloud cover, satellite-borne commercial Synthetic Aperture Radar (SAR) enabled frequent monitoring of Merapi volcano's 2010 eruption. Near-real-time interpretation of images derived from the amplitude of the SAR signals and timely delivery of these interpretations to those responsible for warnings, allowed satellite remote sensing for the first time to play an equal role with in situ seismic, geodetic and gas monitoring in guiding life-saving decisions during a major volcanic crisis. Our remotely sensed data provide an observational chronology for the main phase of the 2010 eruption, which lasted 12 days (26 October-7 November, 2010). Unlike the prolonged low-rate and relatively low explosivity dome-forming and collapse eruptions of recent decades at Merapi, the eruption began with an explosive eruption that produced a new summit crater on 26 October and was accompanied by an ash column and pyroclastic flows that extended 8 km down the flanks. This initial explosive event was followed by smaller explosive eruptions on 29 October-1 November, then by a period of rapid dome growth on 1-4 November, which produced a summit lava dome with a volume of ~ 5 × 106 m3. A paroxysmal VEI 4 magmatic eruption (with ash column to 17 km altitude) destroyed this dome, greatly enlarged the new summit crater and produced extensive pyroclastic flows (to ~ 16 km radial distance in the Gendol drainage) and surges during the night of 4-5 November. The paroxysmal eruption was followed by a period of jetting of gas and tephra and by a second short period (12 h) of rapid dome growth on 6 November. The eruption ended with low-level ash and steam emissions that buried the 6 November dome with tephra and continued at low levels until seismicity decreased to background levels by about 23 November. Our near-real-time commercial SAR documented the explosive events on 26 October and 4-5 November and high rates of dome growth (> 25 m3 s- 1). An event tree analysis for the previous

  13. Estimation of eruption source parameters from umbrella cloud or downwind plume growth rate

    NASA Astrophysics Data System (ADS)

    Pouget, Solène; Bursik, Marcus; Webley, Peter; Dehn, Jon; Pavolonis, Michael

    2013-05-01

    We introduce a new method to estimate mass eruption rate (MER) and mass loading from the growth of a volcanic umbrella cloud or downwind plume using satellite images, or photographs where ground-based observations are available. This new method is compared with pre-existing models and documented mass eruption rate given in the research literature. We applied the method to five well-studied eruptions (Mount St. Helens, 1980; Redoubt, 1990; Pinatubo, 1991; Hekla, 2000 and Eyjafjallajökull, 2010) and to five less well-documented eruptions (Kliuchevsko'i, 1994; Okmok, 2008; Kasatochi, 2008; Sarychev Peak, 2009 and Bezymianny, 2012). The mass eruption rate is obtained by estimation of the radius of the umbrella cloud with time or by estimation of the width of the downwind plume with distance from the volcano. The results given by the new method show a more fully characterized MER as a function of time than do the results given by pre-existing methods, and allow a faster, remote assessment of the mass eruption rate, even for volcanoes that are difficult to study. The method thus may provide an additional important path to the estimation of source parameters and the forecasting of ash cloud propagation. In addition, in cases where numerous methods are available, use of the method yields new, independent measures of mass eruption rate, hence an ability to estimate uncertainty in mass eruption rate, which could be used in probabilistic estimations of ash cloud propagation.

  14. The Measurement of Self-Rated Depression: A Multidimensional Approach.

    ERIC Educational Resources Information Center

    Bolon, Kevin; Barling, Julian

    1980-01-01

    Investigates the capacity of the Zung Self-Rating Depression Scale for providing specific multidimensional descriptors of depressive behavior. Ideational, physiological and behavioral depression factors were evident in data from 96 normal, white university student volunteers. (Author/RH)

  15. Relationship between cell proliferation and eruption rate in the rat incisor.

    PubMed

    Gomes, J R; Omar, N F; Do Carmo, E R; Neves, J S; Soares, M A M; Narvaes, E A; Novaes, P D

    2013-07-01

    The aim of this study was to further define the relationship between cell proliferation and the rate of tooth eruption in the rat incisor. Vinblastine is a drug that blocks cellular mitosis and was used to inhibit cell proliferation in the odontogenic region of rat incisors that were submitted to a shortening treatment or to higher masticatory forces. Male Wistar rats were divided into five groups: normofunctional (control group for incisor eruption), hypofunctional (incisor submitted to eruption acceleration), hyperfunctional (incisors under higher masticatory forces), hypofunctional with vinblastine and hyperfunctional with vinblastine. In incisors submitted to shortening procedures, a significant decrease in the eruption rate and cell proliferation was observed two days after vinblastine injection, suggesting that incisor eruption is dependent on cell proliferation.

  16. Surface deformation versus eruption rates of the two Eyjafjallajökull 2010 eruptions; implications for the magma plumbing system and origin of melts

    NASA Astrophysics Data System (ADS)

    Pedersen, R.; Sigmundsson, F.; Hreinsdottir, S.; Arnadottir, T.; Hoskuldsson, A.; Gudmundsson, M. T.; Magnusson, E.

    2010-12-01

    Repeated geodetic measurements reveal how active volcanoes deform at the surface, and data inversion facilitates inferences about the related volume changes of underlying deformation sources. During an eruption, drainage from a shallow magma chamber can lead to direct correlation between magma flow rate and deformation rates, as observed previously in Iceland. In the simplest case, a constant scale factor relates magma flow rates, deformation rates on the surface, and inferred volume contraction of subsurface sources. The scale factor will depend on magma source geometry, compressibility of residing magma and rheological properties of the crustal rocks. During the two eruptions of the Eyjafjallajökull volcano, Iceland, in 2010 an entirely different behaviour was observed. This behaviour may be related to the rather unique plumbing system of this particular Icelandic volcano, which appears to have no shallow magma chamber. For the initial flank eruption, where olivine basalt were erupted during a period of about 3 weeks, the average eruption rate was comparable to the inferred flow rate during formation of a pre-eruptive network of intrusions. Detailed GPS and InSAR measurements have revealed a model for the subsurface magma plumbing system active prior to and during the events with multiple sills around 5 km depth. Such intrusions have occurred intermittently in this particular volcano for the past 18 years. During the subsequent explosive trachy-andesitic summit eruption, the relation between deformation rate and magma flow rate is more complex. A large discrepancy exists between the inferred erupted volume and the computed volume change based on the associated surface deformation. When recalculated to dense rock equivalent, the inferred volume change responsible for the main deformation is about one order of magnitude smaller than the sum of mapped erupted volumes. Furthermore, the spatial pattern of the deformation is complex, and not directly related to the

  17. Magma Supply Rate Controls Vigor (And Longevity) of Kīlauea's Ongoing East Rift Zone Eruption

    NASA Astrophysics Data System (ADS)

    Poland, M. P.; Anderson, K. R.

    2015-12-01

    Since 1983, Kīlauea Volcano, Hawai'i, has erupted almost continuously from vents on the East Rift Zone—at 32 years and counting, this is the longest-duration eruption in the past 500 years. Although forecasting the onset of eruptive activity using geophysical, geochemical, and geological monitoring has been demonstrated repeatedly at Kīlauea and elsewhere, little progress has been made in forecasting an eruption's waning or end, particularly in the case of long-lived eruptions. This is especially important at Kīlauea for at least two reasons: (1) caldera formation at the end of another decades-long eruption, in the 15th century, raises the possibility of a link between eruption duration and caldera formation; and (2) long-lived eruptions can have an enduring effect on local population and infrastructure, as demonstrated by the repeated destruction of property by Kīlauea's ongoing rift zone eruption. Data from the past 15 years indicate that the magma supply rate to Kīlauea is an important control on eruptive activity. Joint inversions of geophysical, geochemical, and geological observations demonstrate that in 2006 the supply rate was nearly double that of 2000-2001, resulting in an increase in lava discharge, summit inflation, and the formation of new eruptive vents. In contrast, the magma supply during 2012, and likely through 2014, was less than that of 2000-2001. This lower supply rate was associated with a lower lava discharge and may have played a role in the stalling of lava flows above population centers in the Puna District during 2014-2015. Heightened eruptive vigor may be expected if magma supply increases in the future; however, a further decrease in supply rate—which is likely already below the long-term average—may result in cessation of the eruption. Multidisciplinary monitoring, and particularly tracking of CO2 emissions and surface deformation, should be able to detect changes in supply rate before they are strongly manifested at the

  18. Testing the accuracy of a 1-D volcanic plume model in estimating mass eruption rate

    USGS Publications Warehouse

    Mastin, Larry G.

    2014-01-01

    During volcanic eruptions, empirical relationships are used to estimate mass eruption rate from plume height. Although simple, such relationships can be inaccurate and can underestimate rates in windy conditions. One-dimensional plume models can incorporate atmospheric conditions and give potentially more accurate estimates. Here I present a 1-D model for plumes in crosswind and simulate 25 historical eruptions where plume height Hobs was well observed and mass eruption rate Mobs could be calculated from mapped deposit mass and observed duration. The simulations considered wind, temperature, and phase changes of water. Atmospheric conditions were obtained from the National Center for Atmospheric Research Reanalysis 2.5° model. Simulations calculate the minimum, maximum, and average values (Mmin, Mmax, and Mavg) that fit the plume height. Eruption rates were also estimated from the empirical formula Mempir = 140Hobs4.14 (Mempir is in kilogram per second, Hobs is in kilometer). For these eruptions, the standard error of the residual in log space is about 0.53 for Mavg and 0.50 for Mempir. Thus, for this data set, the model is slightly less accurate at predicting Mobs than the empirical curve. The inability of this model to improve eruption rate estimates may lie in the limited accuracy of even well-observed plume heights, inaccurate model formulation, or the fact that most eruptions examined were not highly influenced by wind. For the low, wind-blown plume of 14–18 April 2010 at Eyjafjallajökull, where an accurate plume height time series is available, modeled rates do agree better with Mobs than Mempir.

  19. Direct rate measurements of eruption plumes at Augustine volcano: A problem of scaling and uncontrolled variables

    SciTech Connect

    Rose, W.I.; Heiken, G.; Wohletz, K.; Eppler, D.; Barr, S.; Miller, T.; Chuan, R.L.; Symonds, R.B.

    1988-05-10

    The March--April 1986 eruption of Augustine Volcano, Alaska, provided an opportunity to directly measure the flux of gas, aerosol, and ash particles during explosive eruption. Most previous direct measurements of volcanic emission rates are on plumes from fuming volcanoes or on very small eruption clouds. Direct measurements during explosive activity are needed to understand the scale relationships between passive degassing or small eruption plumes and highly explosive events. Conditions on April 3, 1986 were ideal: high winds, clear visibility, moderate activity. Three measurements were made: (1) an airborne correlation spectrometer (Cospec) provided mass flux rates of SO/sub 2/; (2) treated filter samples chemically characteized the plume and (3) a quartz crystal microcascade impactor provided particle size distribution. Atmospheric conditions on April 3 caused the development of a lee wave plume, which allowed us to constrain a model of plume dispersion leading to a forecast map of concentrations of SO/sub 2/ at greater distances from the vent.

  20. Lidar surveys reveal eruptive volumes and rates at Etna, 2007-2010

    NASA Astrophysics Data System (ADS)

    Behncke, Boris; Fornaciai, Alessandro; Neri, Marco; Favalli, Massimiliano; Ganci, Gaetana; Mazzarini, Francesco

    2016-05-01

    The quantification of eruptive activity represents one major challenge in volcanology. Digital comparison of lidar-based elevation models of Etna (Italy) was made to quantify the volumes of volcanics emitted in 2007-2010. During this period, Etna produced several summit paroxysms followed by a flank eruption. We integrated the total volume difference resulting from the subtraction of the 2007 and 2010 digital elevation models with volumes of eruptive products based on field and aerial surveys to attribute volumes with hitherto unrealized precision to poorly constrained eruptions. The total erupted volume of 2007-2010 is >86 × 106 m3, most (~74 × 106 m3) of which is made up by the lava flows of the 2008-2009 flank eruption. The survey also reveals the high lava volume (5.73 × 106 m3) and average eruption rate (~400 m3 s-1) of the 10 May 2008 paroxysm, whose flow front stopped 6.2 km from the vent, not far from the town of Zafferana Etnea.

  1. Role of mechanical erosion in controlling the effusion rate of basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Piombo, Antonello; Tallarico, Andrea; Dragoni, Michele

    2016-09-01

    In many basaltic eruptions, observations show that the effusion rate of magma has a typical dependence on time: the effusion rate curves show first a period of increasing and later a decreasing phase by a maximum value. We present a model to explain this behavior by the emptying of a magma reservoir through a vertical cylindrical conduit with elliptical cross section, coupled with the its widening due to mechanical erosion, produced by the magma flow. The model can reproduce the observed dependence on time of effusion rate in basaltic eruptions. Eruption duration and the maximum value of effusion rate depend on the size of magma chamber, on lava viscosity and strongly on erosion rate per unit traction.

  2. Impact of gamma radiation on the eruption rate of rat incisors

    NASA Astrophysics Data System (ADS)

    El-Faramawy, Nabil; El-Haddad, Khaled; Ali, Mohamed; Talaat, Mona

    2015-09-01

    The present work aims to test the effect of gamma radiation on the rate of eruption of rat incisors. One hundred and five adult male albino rats were used and irradiated at different gamma doses. The effects of irradiation were investigated by numerical measurements of eruption rate, histological investigation using light microscope and spectral analysis using Fourier Transform Infra-Red (FTIR). No detectable changes were observed in the groups with smaller radiation doses. There was a significant decrease in the eruption rate starting from the 4 Gy radiation dose. The observation of histological sections revealed disturbance in cellular elements responsible for eruption as well as periodontal disturbance in the samples irradiated with 4 and 6 Gy. FTIR Spectroscopy of control group and the group irradiated by 0.5 Gy showed similar absorption bands with minor differences. However, samples irradiated by 1 Gy showed significant changes in both molecular structure and conformation related to carbonates and hydroxyl groups. From the previous results, it could be concluded that gamma irradiation negatively affects the eruption rate of the rat incisors especially with higher doses.

  3. Volumes, rates and related hazards of Etna's 2007-2010 eruptions (Italy)

    NASA Astrophysics Data System (ADS)

    Neri, Marco; Behncke, Boris; Fornaciai, Alessandro; Favalli, Massimiliano; Ganci, Gaetana; Mazzarini, Francesco

    2016-04-01

    Digital comparison of two LiDAR-based digital elevation models of the summit area and eastern flank of Mount Etna (Italy), acquired in June 2007 and September 2010, were used to quantify with high accuracy the volumes of eruptive products (lava and pyroclastics) emitted in this time interval. During this period, Etna's activity was characterized by a classical sequence of summit paroxysms followed by a voluminous effusive eruption on the upper east flank (May 2008-July 2009). We integrated the total volume difference resulting from the subtraction of the 2007 DEM from the 2010 DEM with individual, well-constrained volumes of eruptive products based on data from field and aerial surveys to attribute more precise volumes to events that have until now remained poorly constrained. The total volume of 2007-2010 eruptive products is ~86 million cubic meter, by far the largest proportion (~73.6 million cubic meter) of which is represented by the lava flows of the 2008-2009 flank eruption. In spite of being one of the longest-standing flank eruptions of Etna of the past ~350 years, its mean effusion rate of 2 cubic meter per second was rather low. The survey also reveals the unusually high lava volume (~5.8 million cubic meter) of the paroxysmal episode of 10 May 2008, which preceded the flank outbreak by three days, and which was emplaced within four hours at an average rate of ~400 cubic meter per second, the flow front stopping at a distance of 6.2 km from the source vent. With a slightly longer duration of this eruptive episode, that lava flow might have come rather close to the outskirts of the nearby town of Zafferana Etnea.

  4. Implication of the January 1990 Volcanic Eruption on Io for Resurfacing Rates and Energetics

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.; Matson, D. L.; Veeder, G. J.; Blaney, D. L.; Goguen, J. D.

    1993-01-01

    The high temperature event observed by ground based infrared radiometry of Io in January of 1990 can be modeled as an extremely active silicate lava flow which increased its area and cooled over a period of three hours. The best model at the start of the observations is a thermal source at 1200 K with an area equal to that of a circle of 5.6 km radius, while at the end of the observation sequence a source with a temperature of 700 K and a 13 km radium provides the best match. Given a flow thickness of 10 m, this implies an eruption rate of 300,000 cubic meters per second. This is large by terrestrial standards but consistent with estimates of lunar eruption rates (Head and Wilson 1981) and some terrestrial eruptions such as the 1800-1801 Hualalai flow in Hawaii (Baloga and Spudis 1992)...

  5. The Multidimensional Behavior Rating Scale: An Assessment Device for Depression.

    ERIC Educational Resources Information Center

    Rothblum, Esther D.; Green, Leon

    The Multidimensional Behavior Rating Scale (MBRS) was constructed to assess symptoms of depression across seven modalities: behavior, affect, sensation, imagery, cognition, interpersonal relationship, and drugs. Subjects (N=33) were matched by level of depression on the Minnesota Multiphasic Personality Inventory Depression Scale to either a…

  6. Volumes and eruption rates for the 2008-2009 Chaitén rhyolite lava dome

    NASA Astrophysics Data System (ADS)

    Pallister, J. S.; Diefenbach, A. K.; Griswold, J.; Muñoz, J.; Lara, L. E.; Valenzuela, C.; Burton, W. C.; Keeler, R.

    2010-12-01

    The 2008 eruption of Chaitén caldera, southern Chile, was one of the most explosive on Earth in the past two decades. The eruption began early on 2 May 2008 (UTC) and produced sub-plinian to plinian ash columns between 2 May and 9 May, before transitioning from explosive eruption of tephra to effusive eruption of rhyolite lava. A series of lava flow lobes accumulated within the caldera between late May and the end of the year, burying most of Chaitén’s prehistoric lava dome. A prominent lava spine was also extruded, starting in late 2008. The spine collapsed on 19 February 2009, producing a pyroclastic flow that extended out of the caldera and 7 km down the Río Chaitén. Dome growth continued through 2009, filling in much of the spine-collapse area and further expanding the composite dome through endogenous growth. Dome volumes are computed and eruption rates estimated using satellite data from 2008-10, photogrammetric analysis of oblique aerial photographs taken in January 2010, and digital elevation models derived from ASTER, SRTM, LIDAR and topographic maps. The 2008-10 dome has a total volume of approximately 0.8 km3. About 0.5 km3 erupted within the first four months, when extrusion rates were in the range 10-100 m3s-1. Extrusion rates decreased exponentially over the eruptive period. The 2008-10 dome is similar in volume and composition to the prehistoric lava dome, which has a volume of at least 0.5 km3. Together the two domes constitute about 20-40% of the 3.5-7 km3 collapse volume of the prehistoric caldera. The unusually rapid extrusion rates during the first four months are among the highest ever measured for silicic lava. Chaitén’s 2008-10 lava is obsidian and microcrystalline rhyolite with 75.35+/-0.02% SiO2. A large volume of low viscosity crystal-poor magma (about 0.1% phenocrysts) coupled with high extrusion pressures during the extended transition from explosive to effusive eruption style resulted in these exceptionally high extrusion rates.

  7. Lava Tube Flow Models at Alba Patera, Mars: Topographic Constraints on Eruption Rates

    NASA Technical Reports Server (NTRS)

    Riedel, S. J.; Sakimoto, S. E. H.; Bradley, B. A.; DeWet, A.

    2001-01-01

    Alba Patera has some of the longest lava tubes over some of the shallowest slopes on Mars. We use Mars Orbiter Laser Altimeter (MOLA) topography to model eruption rates for several Alba Patera lava tubes and compare them within Alba and with flows from other martian volcanic regions. Additional information is contained in the original extended abstract.

  8. Measuring Depression at the End of Life: Is the Hamilton Depression Rating Scale a Valid Instrument?

    ERIC Educational Resources Information Center

    Olden, Megan; Rosenfeld, Barry; Pessin, Hayley; Breitbart, William

    2009-01-01

    Depression at the end of life is a common mental health issue with serious implications for quality of life and decision making. This study investigated the reliability and validity of one of the most frequently used measures of depression, the Hamilton Depression Rating Scale (HAM-D) in 422 patients with terminal cancer admitted to a palliative…

  9. Rating depression over brief time intervals with the Hamilton Depression Rating Scale: standard vs. abbreviated scales.

    PubMed

    Luckenbaugh, David A; Ameli, Rezvan; Brutsche, Nancy E; Zarate, Carlos A

    2015-02-01

    Although antidepressant trials typically use weekly ratings to examine changes in symptoms over six to 12 weeks, antidepressant treatments may improve symptoms more quickly. Thus, rating scales must be adapted to capture changes over shorter intervals. We examined the use of the 17-item Hamilton Depression Rating Scale (HDRS) to evaluate more rapid changes. Data were examined from 58 patients with major depressive disorder or bipolar disorder enrolled in double-blind, placebo-controlled, crossover studies who received a single infusion of ketamine (0.5 mg/kg) or placebo over 40 min then crossed over to the other condition. HDRS subscales, a single HDRS Depressed mood item, and a visual analogue scale were used at baseline, after a brief interval (230 min), and one week post-infusion. Effect sizes for the ketamine-placebo difference were moderate (d > 0.50), but one and two-item HDRS subscales had the smallest effects. Response rates on active drug were lowest for the complete HDRS (43%); the remaining scales had higher response rates to active drug, but the shortest subscales had higher response rates to placebo. Correlations between the changes from baseline to 230 min post-ketamine across scores were similar for most subscales (r = 0.82-0.97), but correlations using the single items were lower (r < 0.74). Overall, effect sizes for drug-placebo differences and correlations between changes were lower for one- and two-item measures. Response rates were lower with the full HDRS scale. The data suggest that, to best identify rapid antidepressant effects, a scale should have more than two items, but fewer items than a full scale.

  10. Correlation of palaeomagnetic directions constrains eruption rate of large igneous provinces

    NASA Astrophysics Data System (ADS)

    Suttie, Neil; Biggin, Andrew J.; Holme, Richard

    2014-02-01

    The rate of eruption of lava flows in large igneous provinces is a highly controversial topic with implications for the processes by which mass extinctions of life occurred throughout the Phanerozoic. It is also an extremely difficult parameter to measure, but may be accessed through the correlation of palaeomagnetic directions recorded in neighbouring lava flows. The next-neighbour correlation can be described by a single additional parameter which can be evaluated by constructing a suitable covariance matrix. It is found to be a useful proxy for the rate of eruption of Cenozoic lavas from the North Atlantic igneous province and has the potential to help constrain the eruptive histories of other large igneous provinces. Significant next-neighbour correlation is revealed even in the absence of grouping of directions, giving a method of detecting changing eruption rates when there are no magnetostratigraphic markers. Significant correlation is found over timescales of tens of thousands of years in volcanic datasets making it doubtful that records of recent secular variation over shorter timescales can be used as a model for palaeosecular variation. By eliminating next-neighbour correlation, it is demonstrated how estimates of palaeosecular variation may be derived, with formal confidence limits, allowing robust comparisons to be made between sites. Using this method we show that the angular dispersion of the field dropped significantly during the 2.5 million year long polarity chron C24r.

  11. Calculation of Decompression Rates for the Initial Explosive Phase of the 2010 Merapi Eruption

    NASA Astrophysics Data System (ADS)

    Matthews, E.; Genareau, K. D.

    2015-12-01

    The 2010 eruption of Merapi (Java, Indonesia) initiated with an uncharacteristic explosion, followed by rapid lava dome growth and collapse, all of which generated deadly pyroclastic density currents (PDCs). PDC samples from the initial explosion on October 26th were collected from several locations surrounding the edifice. Plagioclase phenocrysts represent the primary component of the dominant ash mode due to the elutriation of the finer ash fraction during PDC transport. Secondary electron images of 45 phenocrysts were taken using the scanning electron microscope (SEM) to examine preserved glass coatings on phenocrysts, which represent the interstitial melt within the magma at the point of fragmentation. Using these images, the bubble number densities (BNDs) were determined, and the decompression rate meter of Toramaru (2006) was used to calculate the decompression rate during the initial explosion of the 2010 Merapi eruption. Calculated decompression rates range from 6.08x10^7 Pa/s to 1.4x10^8 Pa/s. Decompression rates have shown to correlate with eruption column height; therefore Merapi's rates should be similar to those of other Vulcanian explosions, because the eruption column was 8-9 km in height. The decompression rates acquired for Merapi using Toramaru's BND meter are higher than the rates calculated with other methods such as microlite number density and extension cracks in crystals. Sakurajima volcano (Japan) experienced decompression rates from 7.0 × 10^3 to 7.8 × 10^4 Pa/s during the later phase of the fall 2011 Vulcanian explosions. Plinian explosions, such as at the 1991 eruption of Mt. Pinatubo and the 1980 eruption of St. Helens had much higher column heights compared to the initial 2010 Merapi explosion; 35 km, 19 km, and 8-9 km, respectively, but decompression rates in a comparative range (10^8 Pa/s). Higher decompression rates during the 2010 initial explosion at Merapi likely resulted from increased overpressure in the shallow conduit, the

  12. Assessment of Depression in Dementia Patients: Association of Caregiver Mood with Depression Ratings.

    ERIC Educational Resources Information Center

    Teri, Linda; Truax, Paula

    1994-01-01

    Primary caregivers (n=41) of memory-impaired patients rated a standardized stimulus of depression and their actual patient. They were able to correctly identify depression in both. Further, their mood was unassociated with video ratings and only moderately associated with patient ratings. The findings support reliance on caregiver input.…

  13. Trends in the aggregated rate of pre-eruptive volcano-tectonic seismicity at Kilauea volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Bell, Andrew F.; Kilburn, Christopher R. J.

    2013-01-01

    Accelerating rates of volcano-tectonic (VT) earthquakes are commonly observed during volcanic unrest. Understanding the repeatability of their behaviour is essential to evaluating their potential to forecast eruptions. Quantitative eruption forecasts have focused on changes in precursors over intervals of weeks or less. Previous studies at basaltic volcanoes in frequent eruption, such as Kilauea in Hawaii and Piton de La Fournaise on Réunion, suggest that VT earthquake rates tend to follow a power-law acceleration with time about 2 weeks before eruption, but that this trend is often obscured by random fluctuations (or noise) in VT earthquake rate. These previous studies used a stacking procedure, in which precursory sequences for several eruptions are combined to enhance the signal from an underlying acceleration in VT earthquake rate. Such analyses assume a common precursory trend for all eruptions. This assumption is tested here for the 57 eruptions and intrusions recorded at Kilauea between 1959 and 1984. Applying rigorous criteria for selecting data (e.g. maximum depth; restricting magnitudes to be greater than the completeness magnitude, 2.1), we find a much less pronounced increase in the aggregate rate of earthquakes than previously reported. The stacked trend is also strongly controlled by the behaviour of one particular pre-eruptive sequence. In contrast, a robust signal emerges among stacked VT earthquake rates for a subset of the eruptions and intrusions. The results are consistent with two different precursory styles at Kilauea: (1) a small proportion of eruptions and intrusions that are preceded by accelerating rates of VT earthquakes over intervals of weeks to months and (2) a much larger number of eruptions that show no consistent increase until a few hours beforehand. The results also confirm the importance of testing precursory trends against data that have been filtered according to simple constraints on the spatial distribution and completeness

  14. Ascent Rates from Melt Embayments: Insights into the Eruption Dynamics of Arc Volcanoes

    NASA Astrophysics Data System (ADS)

    Ruprecht, P.; Lloyd, A. S.; Hauri, E.; Rose, W. I.; Gonnermann, H. M.; Plank, T. A.

    2014-12-01

    A significant fraction of the magma that is added from the mantle to the subvolcanic plumbing system ultimately erupts at the surface. The initial volatile content of the magmas as well as the interplay between volatile loss and magma ascent plays a significant role in determining the eruption style (effusive versus explosive) as well as the magnitude of the eruption. The October 17, 1974 sub-Plinian eruption of Volcán de Fuego represents a particularly well-characterized system in terms of volatile content and magma chemistry to investigate the relation between initial water content of the magmas and the ascent rate. By modeling volatile element distribution in melt embayments through diffusion and degassing during ascent we can estimate magma ascent from the storage region in the crust to the surface. The novel aspect is the measurement of concentration gradients multiple volatile elements (in particular CO2, H2O, S) at fine-scale (5-10 μm) using the NanoSIMS. The wide range in diffusivity and solubility of these different volatiles provides multiple constraints on ascent timescales over a range of depths. H2O, CO2, and S all decrease toward the embayment outlet bubble documenting the loss of H2O and CO2 compared to an extensive melt inclusion suite from the same day of the eruption. The data is best described by a two-stage model. At high pressure (>145 MPa) decompression is slow (0.05- 0.3 MPa/s) and CO2 is bled off predominantly. At shallow levels decompression accelerates to 0.3-0.5 MPa/s at the point of H2O exsolution, which strongly affects the buoyancy of the ascending magma. The magma ascent rates presented are among the first for explosive basaltic eruptions and demonstrate the potential of the embayment method for quantifying magmatic timescales associated with eruptions of different vigor. [1] Lloyd et al. (2014) JVGR, http://dx.doi.org/10.1016/j.jvolgeores.2014.06.002

  15. Mixed Rasch Modeling of the Self-Rating Depression Scale

    ERIC Educational Resources Information Center

    Hong, Sehee; Min, Sae-Young

    2007-01-01

    In this study, mixed Rasch modeling was used on the Self-Rating Depression Scale (SDS), a widely used measure of depression, among a non-Western sample of 618 Korean college students. The results revealed three latent classes and confirmed the unidimensionality of the SDS. In addition, there was a significant effect for gender in terms of class…

  16. Solar magnetic activity cycles, coronal potential field models and eruption rates

    NASA Astrophysics Data System (ADS)

    Petrie, Gordon

    2013-07-01

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking (CACTus), Solar Eruptive Event Detection System (SEEDS), and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003-2012 than for those between 1997-2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  17. Solar Magnetic Activity Cycles, Coronal Potential Field Models and Eruption Rates

    NASA Astrophysics Data System (ADS)

    Petrie, G. J. D.

    2013-05-01

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  18. SOLAR MAGNETIC ACTIVITY CYCLES, CORONAL POTENTIAL FIELD MODELS AND ERUPTION RATES

    SciTech Connect

    Petrie, G. J. D.

    2013-05-10

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  19. Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    PubMed Central

    Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-01-01

    Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions.

  20. Increased rates of large-magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    NASA Astrophysics Data System (ADS)

    Mahony, S. H.; Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-07-01

    Tephra layers in marine sediment cores from scientific ocean drilling largely record high-magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera-forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ˜8 Ma, 6-4 Ma, and further increase after ˜2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike-slip-dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ˜8 Ma to present period led to (1) increased arc-normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera-forming eruptions.

  1. Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    PubMed Central

    Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-01-01

    Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions. PMID:27656115

  2. Petrological evidence for non-linear increase of magmatic intrusion rates before eruption at open vent mafic volcanoe

    NASA Astrophysics Data System (ADS)

    Ruth, D. C. S.; Costa Rodriguez, F.

    2015-12-01

    The most active volcanoes on earth erupt in a yearly to decadal time scales, typically erupt mafic magmas and are open-vent systems with prominent degassing plumes (e.g. Mayon, Arenal, Llaima, Etna). Here we investigate the plumbing systems, dynamics, and processes that drive eruptions at these systems. These are key questions for improving hazard evaluation, and better understanding the unrest associated with these types of volcanoes. The petrology and geochemistry from six historical eruptions (1947-2006) of Mayon volcano (Philippines) shows that all lavas are basaltic andesite with phenocrysts of plagioclase + orthopyroxene (Opx) + clinopyroxene. Opx crystals show a variety of compositions and zoning patterns (reverse, normal or complex) with Mg# (= 100 *Mg/[Mg+Fe]) varying from 67 to 81. The simplest interpretation is that the low Mg# parts of the crystals resided on an upper crustal and crystal rich reservoir that was intruded by more primitive magmas from which the high Mg# parts of the crystals grew. Modelling Mg-Fe diffusion in Opx shows that times since magma injection and eruption range from a few days up to 3.5 years in all of the investigated eruptions. The longest diffusion times are shorter than the repose times between the eruptions, which implies that crystal recycling between eruptive events is negligible. This is a surprising result that shows that for each eruption a different part of the evolved crystal-rich plumbing system is activated. This can be due to random intrusion location or an irreversibility of the plumbing system that prevents multiple eruptions from the same crystal-rich part. Moreover, we find that the number of intrusions markedly increases before each eruption in a non-linear manner. Such an increased rate of intrusions with time might reflect non-linear rheological properties of the crystal-rich system, of the enclosing rocks, or the non-linear evolution of crystal-melt reaction-dissolution fronts during magma intrusions.

  3. REFIR - The operational FutureVolc multi-parameter system providing a best estimate of mass eruption rate during ongoing eruptions in near real-time

    NASA Astrophysics Data System (ADS)

    Dürig, Tobias

    2016-04-01

    Volcanic ash injected into the atmosphere poses a serious threat for aviation. Forecasting the concentration of ash promptly requires detailed knowledge of eruption source parameters. However, monitoring an ongoing eruption and quantifying the mass flux in real-time is a considerable challenge. Due to the large uncertainties affecting present-day models, best estimates are often obtained by the application of integrated approaches. One example for this strategy is represented by the EU supersite project "FutureVolc" which aims to monitor eruptions of volcanoes in Iceland. A quasi-autonomous multi-parameter system, denoted "REFIR", has been developed. REFIR makes use of streaming data provided by a multitude of sensors, e.g. by C- and X-band radars, web-cam based plume height tracking systems, imaging ultra-violet and infrared cameras and electric field sensors. These observations are used with plume models that also consider the current local wind and other atmospheric conditions, and a best estimate of source parameters, including the mass eruption rate, is provided in near real-time (within a time interval of 5 minutes) as soon as an eruption has started. Since neither the time nor the location of the next Icelandic eruption is known the system has been developed with a guiding principle of maximum flexibility, and it can effortlessly be implemented elsewhere needing minimum adoption to local conditions. Moreover, it is designed to be easily upgraded, which allows future extension of the existing monitoring network, learning from new events, and incorporating new technologies and model improvements. Data-flow, features and integrated models within REFIR will be presented and strategies for implementing potential future research developments on ash plume dynamics will be discussed.

  4. Ground-based measurements of the emission rate and composition of gases from the Holuhraun eruption

    NASA Astrophysics Data System (ADS)

    Pfeffer, Melissa A.; Stefánsdóttir, Gerður; Bergsson, Baldur; Barsotti, Sara; Galle, Bo; Conde, Vladimir; Donovan, Amy; Aiuppa, Alessandro; Burton, Mike; Keller, Nicole S.; Askew, Robert A.; Ilyinskaya, Evgenia; La Spina, Alessandro; Sigurðardóttir, Guðmunda M.; Jónasdóttir, Elín B.; Snorrason, Árni; Stefánsson, Andri; Tsanev, Vitchko

    2015-04-01

    The ongoing fissure eruption at Holuhraun is distinguished by high concentrations of gases being released both from the vent(s) where lava is being extruded and from the cooling lava. The conditions for making ground-based measurements of the gases are particularly challenging: remote location, optically dense plume with high SO2 column amounts, low UV intensity, frequent clouds and precipitation, an extensive and hot lava field, and ramparts around the main vent. Three scanning DOASes capable of streaming data in almost real-time have been installed less than 15 km from the fissure. As of writing, there are two scanning DOASes operating while one unrecoverable instrument has been trapped by the lava. Traverses with a car-mounted DOAS are made along the ring road down-wind from the eruption when conditions are favorable. The SO2 emission rate is greater in the long-range traverses than from the near-source DOAS measurements. The data is being examined so that the uncertainty in the DOAS measurements can be constrained. Preliminary SO2 emission rates for the first month and a half of the eruption are ~400 kg/s with some days greater than 1000 kg/s. Plume composition measurements were made by FTIR, MultiGAS, DOAS and filter pack during multiple campaigns in the first two months of the eruption. The FTIR measurements indicated a significantly drier plume than the MultiGAS measurements. The CO2/SO2 ratio measured by MultiGAS and FTIR agree very well. Mobile DOAS traverses indicate that 80-90 % of the SO2 emissions came from the main vent with the remainder being released by the cooling lava. FTIR measured higher HCl/SO2 ratios from the cooling lava than from the main vent. The last campaign that successfully collected data (in October) showed with both FTIR and MultiGAS a drop in CO2/SO2. Since then, there have been no successful campaign measurements. Further ground-based measurements to determine the relative contribution of the lava field to the total emissions and

  5. Mass eruption rates in pulsating eruptions estimated from video analysis of the gas thrust-buoyancy transition—a case study of the 2010 eruption of Eyjafjallajökull, Iceland

    NASA Astrophysics Data System (ADS)

    Dürig, Tobias; Gudmundsson, Magnús Tumi; Karmann, Sven; Zimanowski, Bernd; Dellino, Pierfrancesco; Rietze, Martin; Büttner, Ralf

    2015-11-01

    The 2010 eruption of Eyjafjallajökull volcano was characterized by pulsating activity. Discrete ash bursts merged at higher altitude and formed a sustained quasi-continuous eruption column. High-resolution near-field videos were recorded on 8-10 May, during the second explosive phase of the eruption, and supplemented by contemporary aerial observations. In the observed period, pulses occurred at intervals of 0.8 to 23.4 s (average, 4.2 s). On the basis of video analysis, the pulse volume and the velocity of the reversely buoyant jets that initiated each pulse were determined. The expansion history of jets was tracked until the pulses reached the height of transition from a negatively buoyant jet to a convective buoyant plume about 100 m above the vent. Based on the assumption that the density of the gas-solid mixture making up the pulse approximates that of the surrounding air at the level of transition from the jet to the plume, a mass flux ranging between 2.2 and 3.5 · 104 kg/s was calculated. This mass eruption rate is in good agreement with results obtained with simple models relating plume height with mass discharge at the vent. Our findings indicate that near-field measurements of eruption source parameters in a pulsating eruption may prove to be an effective monitoring tool. A comparison of the observed pulses with those generated in calibrated large-scale experiments reveals very similar characteristics and suggests that the analysis of near-field sensors could in the future help to constrain the triggering mechanism of explosive eruptions.

  6. Prevalence rates for depression by industry: a claims database analysis

    PubMed Central

    Alterman, Toni; Bushnell, P. Timothy; Li, Jia; Shen, Rui

    2015-01-01

    Purpose To estimate and interpret differences in depression prevalence rates among industries, using a large, group medical claims database. Methods Depression cases were identified by ICD-9 diagnosis code in a population of 214,413 individuals employed during 2002–2005 by employers based in western Pennsylvania. Data were provided by Highmark, Inc. (Pittsburgh and Camp Hill, PA). Rates were adjusted for age, gender, and employee share of health care costs. National industry measures of psychological distress, work stress, and physical activity at work were also compiled from other data sources. Results Rates for clinical depression in 55 industries ranged from 6.9 to 16.2 %, (population rate = 10.45 %). Industries with the highest rates tended to be those which, on the national level, require frequent or difficult interactions with the public or clients, and have high levels of stress and low levels of physical activity. Conclusions Additional research is needed to help identify industries with relatively high rates of depression in other regions and on the national level, and to determine whether these differences are due in part to specific work stress exposures and physical inactivity at work. Clinical significance Claims database analyses may provide a cost-effective way to identify priorities for depression treatment and prevention in the workplace. PMID:24907896

  7. A dynamic balance between magma supply and eruption rate at Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Denlinger, R.P.

    1997-01-01

    The dynamic balance between magma supply and vent output at Kilauea volcano is used to estimate both the volume of magma stored within Kilauea volcano and its magma supply rate. Throughout most of 1991 a linear decline in volume flux from the Kupaianaha vent on Kilauea's east rift zone was associated with a parabolic variation in the elevation of Kilauea's summit as vent output initially exceeded then lagged behind the magma supply to the volcano. The correspondence between summit elevation and tilt established with over 30 years of data provided daily estimates of summit elevation in terms of summit tilt. The minimum in the parabolic variation in summit tilt and elevation (or zero elevation change) occurs when the magma supply to the reservoir from below the volcano equals the magma output from the reservoir to the surface, so that the magma supply rate is given by vent flux on that day. The measurements of vent flux and tilt establish that the magma supply rate to Kilauea volcano on June 19, 1991, was 217,000 ?? 10,000 m3/d (or 0.079 ?? 0.004 km3/yr). This is close to the average eruptive rate of 0.08 km3/yr between 1958 and 1984. In addition, the predictable response of summit elevation and tilt to each east rift zone eruption near Puu Oo since 1983 shows that summit deformation is also a measure of magma reservoir pressure. Given this, the correlation between the elevation of the Puu Oo lava lake (4 km uprift of Kupaianaha and 18 km from the summit) and summit tilt provides an estimate for magma pressure changes corresponding to summit tilt changes. The ratio of the change in volume to the change in reservoir pressure (dV/dP) during vent activity may be determined by dividing the ratio of volume erupted to change in summit tilt (dV/dtilt) by the ratio of pressure change to change in summit tilt (dP/dtilt). This measure of dV/dP, when combined with laboratory measurements of the bulk modulus of tholeitic melt, provides an estimate of 240 ?? 50 km3 for the volume

  8. Depression.

    PubMed

    Stewart, Donna E; Gucciardi, Enza; Grace, Sherry L

    2004-08-25

    HEALTH ISSUE: Depression causes significant distress or impairment in physical, social, occupational and other key areas of functioning. Women are approximately twice as likely as men to experience depression. Psychosocial factors likely mediate the risks for depression incurred by biological influences. KEY FINDINGS: Data from the 1999 National Population Health Survey show that depression is more common among Canadian women, with an annual self-reported incidence of 5.7% compared with 2.9% in men. The highest rates of depression are seen among women of reproductive age. Predictive factors for depression include previous depression, feeling out of control or overwhelmed, chronic health problems, traumatic events in childhood or young adulthood, lack of emotional support, lone parenthood, and low sense of mastery. Although depression is treatable, only 43% of depressed women had consulted a health professional in 1998/99 and only 32.4% were taking antidepressant medication. People with lower education, inadequate income, and fewer contacts with a health professional were less likely to receive depression treatment. DATA GAPS AND RECOMMENDATIONS: A better understanding of factors that increase vulnerability and resilience to depression is needed. There is also a need for the collection and analysis of data pertaining to: prevalence of clinical anxiety; the prevalence of depression band 12 months after childbirth factors contributing to suicide contemplation and attempts among adolescent girls, current treatments for depression and their efficacy in depressed women at different life stages; interprovincial variation in depression rates and hospitalizations and the impact and costs of depression on work, family, individuals, and society.

  9. Advances in psychiatric epidemiology: rates and risks for major depression.

    PubMed Central

    Weissman, M M

    1987-01-01

    Over the last decade there has been a marked increase in information on the epidemiology of psychiatric disorders, particularly major depression, in adults living in the community and in families. The ability to conduct large epidemiologic studies of psychiatric disorders is due to improvements in diagnostic precision and reliability in psychiatry and to the development of systematic methods for collecting information on signs and symptoms to make diagnoses. Results from a recently completed epidemiologic survey of psychiatric disorders in five urban communities in the United States and from several large-scale family genetic studies suggest that major depression is a highly prevalent disorder. It occurs in adults and children, and there is evidence for an increased rate in younger people. The average age of first onset is in young adulthood. Most depressions are untreated. The firm risk factors for major depression include being female; young (born after World War II); separated/divorced or in an unhappy marriage; and having a family history of major depression. There is a two-to-threefold increased risk for major depression if there is a family history of the disorder. The relevance of these findings to clinical practice and public health is discussed. PMID:3826462

  10. Teacher and Parent Ratings of Children with Depressive Disorders

    ERIC Educational Resources Information Center

    Mattison, Richard E.; Carlson, Gabrielle A.; Cantwell, Dennis P.; Asarnow, Joan Rosenbaum

    2007-01-01

    The fields of child psychology and psychiatry have not yet established the clinical presentation in school of children and adolescents who have been diagnosed as having a depressive disorder. To address this issue, the authors used teacher ratings on scale oriented to the third, revised edition of the "Diagnostic and Statistical Manual of Mental…

  11. Quantitative Approach To Seamount Volumes And Eruption Rates For Serpentinite Mud Volcanoes

    NASA Astrophysics Data System (ADS)

    Fedenczuk, T.; Fryer, P.

    2008-12-01

    for locations where workers do not have a strong geologic familiarity or experience. The oldest serpentinite muds date back to the initiation of subduction in the Mariana region in the Eocene. As a first approximation, dividing the volume of each seamount by 50 Ma yields a long-term eruption rate of 2.4 × 10-5 km3/year for Big Blue (largest seamount), and 3.26 ×10-5 km3/year for Conical (smallest seamount). As a comparison, these rates are approximately three to four orders of magnitude smaller than the igneous eruption rates for the Emperor Seamounts (1.0×10-2 km3/year). These rates are probably underestimates because some of the seamounts may have formed more recently, and because they erupt episodically. Expanding these calculations to include the volumes of all known serpentinite volcanoes in the Mariana forearc would give us a minimum estimate for the serpentinite production rate since the inception of subduction. Finally, we estimate the volume of the source protolith (peridotite) required to form the seamounts, using both a simple cylindrical model and a more complex cylindrical/cone model, assuming that the volume of the seamount approximates the volume of the protolith serpentinized minus the increase in volume (25-30%) caused by serpentinization. The calculated volumes of all of the seamounts needed a source conduit larger than 2km in diameter to produce enough serpentinite, requiring a more complex cone/cylinder model or an additional source of the protolith.

  12. Human life history evolution explains dissociation between the timing of tooth eruption and peak rates of root growth.

    PubMed

    Dean, M Christopher; Cole, Tim J

    2013-01-01

    We explored the relationship between growth in tooth root length and the modern human extended period of childhood. Tooth roots provide support to counter chewing forces and so it is advantageous to grow roots quickly to allow teeth to erupt into function as early as possible. Growth in tooth root length occurs with a characteristic spurt or peak in rate sometime between tooth crown completion and root apex closure. Here we show that in Pan troglodytes the peak in root growth rate coincides with the period of time teeth are erupting into function. However, the timing of peak root velocity in modern humans occurs earlier than expected and coincides better with estimates for tooth eruption times in Homo erectus. With more time to grow longer roots prior to eruption and smaller teeth that now require less support at the time they come into function, the root growth spurt no longer confers any advantage in modern humans. We suggest that a prolonged life history schedule eventually neutralised this adaptation some time after the appearance of Homo erectus. The root spurt persists in modern humans as an intrinsic marker event that shows selection operated, not primarily on tooth tissue growth, but on the process of tooth eruption. This demonstrates the overarching influence of life history evolution on several aspects of dental development. These new insights into tooth root growth now provide an additional line of enquiry that may contribute to future studies of more recent life history and dietary adaptations within the genus Homo. PMID:23342167

  13. Human life history evolution explains dissociation between the timing of tooth eruption and peak rates of root growth.

    PubMed

    Dean, M Christopher; Cole, Tim J

    2013-01-01

    We explored the relationship between growth in tooth root length and the modern human extended period of childhood. Tooth roots provide support to counter chewing forces and so it is advantageous to grow roots quickly to allow teeth to erupt into function as early as possible. Growth in tooth root length occurs with a characteristic spurt or peak in rate sometime between tooth crown completion and root apex closure. Here we show that in Pan troglodytes the peak in root growth rate coincides with the period of time teeth are erupting into function. However, the timing of peak root velocity in modern humans occurs earlier than expected and coincides better with estimates for tooth eruption times in Homo erectus. With more time to grow longer roots prior to eruption and smaller teeth that now require less support at the time they come into function, the root growth spurt no longer confers any advantage in modern humans. We suggest that a prolonged life history schedule eventually neutralised this adaptation some time after the appearance of Homo erectus. The root spurt persists in modern humans as an intrinsic marker event that shows selection operated, not primarily on tooth tissue growth, but on the process of tooth eruption. This demonstrates the overarching influence of life history evolution on several aspects of dental development. These new insights into tooth root growth now provide an additional line of enquiry that may contribute to future studies of more recent life history and dietary adaptations within the genus Homo.

  14. Calculation of lava discharge rates during effusive eruptions: an empirical approach using MODIS Middle InfraRed data

    NASA Astrophysics Data System (ADS)

    Coppola, Diego; Laiolo, Marco; Cigolini, Corrado

    2016-04-01

    The rate at which the lava is erupted is a crucial parameter to be monitored during any volcanic eruption. However, its accurate and systematic measurement, throughout the whole duration of an event, remains a big challenge, also for volcanologists working on highly studied and well monitored volcanoes. The thermal approach (also known as thermal proxy) is actually one of most promising techniques adopted during effusive eruptions, since it allows to estimate Time Averaged lava Discharge Rates (TADR) from remote-sensed infrared data acquired several time per day. However, due to the complexity of the physic behind the effusive phenomenon and the difficulty to have field validations, the application of the thermal proxy is still debated and limited to few volcanoes only. Here we present the analysis of MODIS Middle InfraRed data, collected by during several distinct eruptions, in order to show how an alternative, empirical method (called radiant density approach; Coppola et al., 2013) permit to estimate TADRs over a wide range of emplacement styles and lava compositions. We suggest that the simplicity of this empirical approach allows its rapid application during eruptive crisis, and provides the basis for more complex models based on the cooling and spreading processes of the active lava bodies.

  15. Content, Imagery, Social Desirability, & Emotionality Ratings for Depressed & Nondepressed Personal Adjectives.

    ERIC Educational Resources Information Center

    Derry, Paul A.; Kuiper, Nicholas A.

    Recent studies have suggested that depressives process personal information in a biased and negative self-referential manner. Normative ratings on a variety of "depressed" and "nondepressed" adjectives were obtained to investigate the exact nature of information processing in depressives. Subjects rated adjectives on depressive content, imagery,…

  16. Source mass eruption rate retrieved from satellite-based data using statistical modelling

    NASA Astrophysics Data System (ADS)

    Gouhier, Mathieu; Guillin, Arnaud; Azzaoui, Nourddine; Eychenne, Julia; Valade, Sébastien

    2015-04-01

    Ash clouds emitted during volcanic eruptions have long been recognized as a major hazard likely to have dramatic consequences on aircrafts, environment and people. Thus, the International Civil Aviation Organization (ICAO) established nine Volcanic Ash Advisory Centers (VAACs) around the world, whose mission is to forecast the location and concentration of ash clouds over hours to days, using volcanic ash transport and dispersion models (VATDs). Those models use input parameters such as plume height (PH), particle size distribution (PSD), and mass eruption rate (MER), the latter being a key parameter as it directly controls the amount of ash injected into the atmosphere. The MER can be obtained rather accurately from detailed ground deposit studies, but this method does not match the operational requirements in case of a volcanic crisis. Thus, VAACs use empirical laws to determine the MER from the estimation of the plume height. In some cases, this method can be difficult to apply, either because plume height data are not available or because uncertainties related to this method are too large. We propose here an alternative method based on the utilization of satellite data to assess the MER at the source, during explosive eruptions. Satellite-based techniques allow fine ash cloud loading to be quantitatively retrieved far from the source vent. Those measurements can be carried out in a systematic and real-time fashion using geostationary satellite, in particular. We tested here the relationship likely to exist between the amount of fine ash dispersed in the atmosphere and of coarser tephra deposited on the ground. The sum of both contributions yielding an estimate of the MER. For this purpose we examined 19 eruptions (of known duration) in detail for which both (i) the amount of fine ash dispersed in the atmosphere, and (ii) the mass of tephra deposited on the ground have been estimated and published. We combined these data with contextual information that may

  17. NanoSIMS results from olivine-hosted melt embayments: Magma ascent rate during explosive basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Lloyd, Alexander S.; Ruprecht, Philipp; Hauri, Erik H.; Rose, William; Gonnermann, Helge M.; Plank, Terry

    2014-08-01

    The explosivity of volcanic eruptions is governed in part by the rate at which magma ascends and degasses. Because the time scales of eruptive processes can be exceptionally fast relative to standard geochronometers, magma ascent rate remains difficult to quantify. Here we use as a chronometer concentration gradients of volatile species along open melt embayments within olivine crystals. Continuous degassing of the external melt during magma ascent results in diffusion of volatile species from embayment interiors to the bubble located at their outlets. The novel aspect of this study is the measurement of concentration gradients in five volatile elements (CO2, H2O, S, Cl, F) at fine-scale (5-10 μm) using the NanoSIMS. The wide range in diffusivity and solubility of these different volatiles provides multiple constraints on ascent timescales over a range of depths. We focus on four 100-200 μm, olivine-hosted embayments erupted on October 17, 1974 during the sub-Plinian eruption of Volcán de Fuego. H2O, CO2, and S all decrease toward the embayment outlet bubble, while F and Cl increase or remain roughly constant. Compared to an extensive melt inclusion suite from the same day of the eruption, the embayments have lost both H2O and CO2 throughout the entire length of the embayment. We fit the profiles with a 1-D numerical diffusion model that allows varying diffusivities and external melt concentrations as a function of pressure. Assuming a constant decompression rate from the magma storage region at approximately 220 MPa to the surface, H2O, CO2 and S profiles for all embayments can be fit with a relatively narrow range in decompression rates of 0.3-0.5 MPa/s, equivalent to 11-17 m/s ascent velocity and an 8 to 12 minute duration of magma ascent from ~ 10 km depth. A two stage decompression model takes advantage of the different depth ranges over which CO2 and H2O degas, and produces good fits given an initial stage of slow decompression (0.05-0.3 MPa/s) at high

  18. Co-variation in Magma Compositions, Effusion rates and Seismic Tremor During the 2014-15 Eruption of Fogo volcano, Cape Verde Islands

    NASA Astrophysics Data System (ADS)

    Day, S. J.

    2015-12-01

    Magma compositions vary widely within many eruptions of ocean island volcanoes, particularly those in the Canaries and Cape Verde Islands. The 23 November 2014 to 7 February 2015 eruption of Fogo in the Cape Verde Islands was the first eruption in either the Canaries or the Cape Verdes to be monitored by multiple satellite instruments that measured infrared emissions of the eruption and so enabled continuous quantitative estimation of magma effusion rates and their variation through time. It is also the first eruption in the Cape Verdes for which seismic tremor intensity, indicative of magma ascent dynamics, was continuously recorded. Effusion rates were highest, peaking at about 20 m3/s, in the first five days of eruption but later asymptotic decay in effusion rate was interrupted around 9 and 16 December by pulses of increased effusion. Activity was mainly mildly explosive from December 31, accompanied by intensified seismic tremor. A final pulse of low-rate lava effusion occurred from 17 to 22 January. These data provide a new framework within which to relate compositional variations in the eruption to variations in magma ascent and effusion. We collected a suite of samples whose dates of emplacement have been determined from the date of incandescence of each sample site in high-resolution thermal infrared emissivity maps collected by satellite during the eruption. The samples are highly porphyritic and strongly alkaline in composition, as is typical of Fogo magmas. The first- (November 23/24) and last- (January) erupted magma batches show evidence for hybridization with more evolved magma batches, and the 9 and 16 December magma pulses may be distinct from the magma erupted during the main phase of the eruption. We present data on the samples that allow us to examine the hypothesis that the effusion rate variations were controlled by tapping of different parts of the magma reservoir or reservoirs during the eruption.

  19. Forward and Inverse Modeling of Magma Chamber Dynamics and Crystal Zoning Provides Insights into Rates and Processes Leading to Eruption

    NASA Astrophysics Data System (ADS)

    Costa Rodriguez, F.; Bouvet de Maisonneuve, C.; Degruyter, W.; Huber, C.

    2014-12-01

    Chemical and textural features of crystals provide unique constrains on the processes and rates that occur during the growth, replenishment and eruption of magma reservoirs. Recent studies that use different methods have highlighted that many eruptions are issued from reservoirs that may grow for up to hundreds of thousands years (e.g, U-Th series of mineral separates, zircon dating). In contrast, the effect of new magma injections (recharges) can influence the thermodynamic state of reservoirs on a much shorter scale. In extreme cases it can lead to remobilization of magmas over months (for small reservoirs) to thousands of years (for larger systems). Modeling of mineral zoning provides a lower bound estimate for the timescales associated with magma recharge because (a) they do not record dissolution/resorbtion of phases and (b) they only record the time at which a crystal reacts to a thermodynamic change, which does not necessarily equate with the timing of an intrusion. In open system reservoirs, magmas may experience significant thermal and compositional fluctuations over time, and so far, only simple cooling scenarios [1] have been considered. In particular, under what conditions does a recharge lead to an eruption? Can large recharge events be mostly recycled and partially involved in later eruptions? Here we combine new forward models of magma chamber replenishment and evolution [2] that track the thermodynamic evolution of shallow resevoir with crystal zoning models. We explore several scenarios of magma reservoir growth and evolution and compare them to the time scales obtained from the crystal zoning (e.g. thermal history and boundary condition changes with time). Inverse modeling of natural crystal zoning profiles from the silicic eruptions of Rabaul caldera in 1994 and 2006 allows us to distinguish between scenarios where inputs of fresh magma leads to eruption and recharges that are accommodated by the reservoir over longer time scales and are

  20. Detection and estimation of volcanic eruption onset and mass flow rate using weather radar and infrasonic array

    NASA Astrophysics Data System (ADS)

    Marzano, Frank S.; Mereu, Luigi; Montopoli, Mario; Picciotti, Errico; Di Fabio, Saverio; Bonadonna, Costanza; Marchetti, Emanuele; Ripepe, Maurizio

    2015-04-01

    The explosive eruption of sub-glacial Eyjafjallajökull volcano in 2010 was of modest size, but ash was widely dispersed over Iceland and Europe. The Eyjafjallajökull pulsating explosive activity started on April 14 and ended on May 22. The combination of a prolonged and sustained ejection of volcanic ash and persistent northwesterly winds resulted in dispersal the volcanic cloud over a large part of Europe. Tephra dispersal from an explosive eruption is a function of multiple factors, including magma mass flow rate (MFR), degree of magma fragmentation, vent geometry, plume height, particle size distribution (PSD) and wind velocity. One of the most important geophysical parameters, derivable from the analysis of tephra deposits, is the erupted mass, which is essential for the source characterization and assessment of the associated hazards. MFR can then be derived by dividing the erupted mass by the eruption duration (if known) or based on empirical and analytical relations with plume height. Microwave weather radars at C and X band can provide plume height, ash concentration and loading, and, to some extent, PSD and MFR. Radar technology is well established and can nowadays provide fast three-dimensional (3D) scanning antennas together with Doppler and dual polarization capabilities. However, some factors can limit the detection and the accuracy of the radar products aforementioned. For example, the sensitivity of microwave radar measurements depends on the distance between the radar antenna and the target, the transmitter central wavelength, receiver minimum detachable power and the resolution volume. In addition, radar measurements are sensitive to particle sizes larger than few tens of microns thus limiting the radar-based quantitative estimates to the larger portion of the PSD. Volcanic activity produces infrasonic waves (i.e., acoustic waves below 20 Hz), which can propagate in the atmosphere useful for the remote monitoring of volcanic activity. Infrasound

  1. Assessment of Anxiety in Clinical Trials with Depressed Patients Using the Hamilton Depression Rating Scale

    PubMed Central

    Goldberger, C.; Guelfi, J.D.; Sheehan, D.V.

    2011-01-01

    Background The Hamilton Depression Rating Scale (HAMD17) is an outcome measure widely used in major depressive disorder (MDD) clinical trials. The objective of this analysis was to assess the validity of the anxiety/somatisation factor of the HAMD17 as a measure of anxiety in patients with MDD. Methods We pooled data from 1466 outpatients with MDD from four 8-week controlled studies of duloxetine. We performed a factor analysis of the HAMD17 to investigate the anxiety/somatisation factor. Results The HAMD17 factor analysis yielded 6 factors, but did not yield the pre-specified anxiety/somatisation factor. This latter factor showed weak correlation with the Hamilton Anxiety Scale total and subscale scores at baseline (0.46), but higher correlation coefficients over the trials up to 0.81. We identified another anxiety factor that included the hypochondriasis item in this sample. Conclusion Findings from this large sample suggest that the factor structure of the HAMD17 is unstable in MDD and that the anxiety/somatisation subscale should not be routinely used for anxiety assessment in depressed patients.

  2. Ice-melt rates during volcanic eruptions within water-drained, low-pressure subglacial cavities

    NASA Astrophysics Data System (ADS)

    Woodcock, D. C.; Lane, S. J.; Gilbert, J. S.

    2016-02-01

    Subglacial volcanism generates proximal and distal hazards including large-scale flooding and increased levels of explosivity. Direct observation of subglacial volcanic processes is infeasible; therefore, we model heat transfer mechanisms during subglacial eruptions under conditions where cavities have become depressurized by connection to the atmosphere. We consider basaltic eruptions in a water-drained, low-pressure subglacial cavity, including the case when an eruption jet develops. Such drained cavities may develop on sloping terrain, where ice may be relatively shallow and where gravity drainage of meltwater will be promoted. We quantify, for the first time, the heat fluxes to the ice cavity surface that result from steam condensation during free convection at atmospheric pressure and from direct and indirect radiative heat transfer from an eruption jet. Our calculations indicate that the direct radiative heat flux from a lava fountain (a "dry" end-member eruption jet) to ice is c. 25 kW m-2 and is a minor component. The dominant heat transfer mechanism involves free convection of steam within the cavity; we estimate the resulting condensation heat flux to be c. 250 kW m-2. Absorption of radiation from a lava fountain by steam enhances convection, but the increase in condensing heat flux is modest at c. 25 kW m-2. Overall, heat fluxes to the ice cavity surface are likely to be no greater than c. 300 kW m-2. These are comparable with heat fluxes obtained by single phase convection of water in a subglacial cavity but much less than those obtained by two-phase convection.

  3. Self-Rated Depression Severity Relative to Clinician-Rated Depression Severity: Trait Stability and Potential Role in Familial Transmission of Suicidal Behavior.

    PubMed

    John Mann, J; Ellis, Steven P; Currier, Dianne; Zelazny, Jamie; Birmaher, Boris; Oquendo, Maria A; Kolko, David J; Stanley, Barbara; Melhem, Nadine; Burke, Ainsley K; Brent, David A

    2016-07-01

    Self-rated depression and hopelessness severity are predictors of suicide attempt in major depression. This study evaluated whether: (1) greater self-rated distress relative to severity of clinician-rated depression is a trait; (2) that trait is familial; and (3) that trait is linked to familial transmission of suicidal behavior. A total of 285 mood disorder probands and 457 offspring were assessed twice, at least 1 year apart. Family and subject intra-class correlations for self-report depression and hopelessness, controlling for clinician-rated depression severity, were computed. Mixed general linear models determined offspring-proband correlations. Within-individual intra-class correlation (ICC) for depression-hopelessness was 37.8% (bootstrap 95% CI: 31.0-46.3%). Parent-offspring ICC was 10.7% (bootstrap 95% CI: 3.5-17.8%). Suicide attempt concordant parent-offspring correlation for subjective depression was positive, but negative for attempter parent and nonattempter offspring (p = .0213 for slope interaction). Pessimism was greater in proband or offspring attempters than proband or offspring nonattempters (p < .05). Self-reported hopelessness is partly trait-dependent, and there is modest familial transmission of self-reported depression linked to suicidal behavior that may partly explain familial transmission of suicidal behavior. PMID:27046009

  4. Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions

    USGS Publications Warehouse

    Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.

    1994-01-01

    Airborne measurements of sulfur dioxide emission rates in the gas plume emitted from fumaroles in the summit crater of Redoubt Volcano were started on March 20, 1990 using the COSPEC method. During the latter half of the period of intermittent dome growth and destruction, between March 20 and mid-June 1990, sulfur dioxide emission rates ranged from approximately 1250 to 5850 t/d, rates notably higher than for other convergent-plate boundary volcanoes during periods of active dome growth. Emission rates following the end of dome growth from late June 1990 through May 1991 decreased steadily to less than 75 t/d. The largest mass of sulfur dioxide was released during the period of explosive vent clearing when explosive degassing on December 14-15 injected at least 175,000 ?? 50,000 tonnes of SO2 into the atmosphere. Following the explosive eruptions of December 1989, Redoubt Volcano entered a period of intermittent dome growth from late December 1989 to mid-June 1990 during which Redoubt emitted a total mass of SO2 ranging from 572,000 ?? 90,000 tonnes to 680,000 ?? 90,000 tonnes. From mid-June 1990 through May 1991, the volcano was in a state of posteruption degassing into the troposphere, producing approximately 183,000 ?? 50,000 tonnes of SO2. We estimate that Redoubt Volcano released a minimum mass of sulfur dioxide of approximately 930,000 tonnes. While COSPEC data were not obtained frequently enough to enable their use in eruption prediction, SO2 emission rates clearly indicated a consistent decline in emission rates between March through October 1990 and a continued low level of emission rates through the first half of 1991. Values from consecutive daily measurements of sulfur dioxide emission rates spanning the March 23, 1990 eruption decreased in the three days prior to eruption. That decrease was coincident with a several-fold increase in the frequency of shallow seismic events, suggesting partial sealing of the magma conduit to gas loss that resulted in

  5. Teachers' Ratings of Social Competence of Children with High Versus Low Levels of Depressive Symptoms.

    ERIC Educational Resources Information Center

    Shah, Farhana; Morgan, Sam B.

    1996-01-01

    Examined the relationship between children's self-ratings of depressive symptoms and teachers' ratings of the children's situational social competence. Results show that teachers rated those children who reported high levels of depressive symptoms as having more problems in social competence when compared to children who reported low levels of…

  6. The structure of the Montgomery-Åsberg depression rating scale over the course of treatment for depression.

    PubMed

    Quilty, Lena C; Robinson, Jennifer J; Rolland, Jean-Pierre; Fruyt, Filip De; Rouillon, Frédéric; Bagby, R Michael

    2013-09-01

    The Montgomery-Åsberg Depression Rating Scale (MADRS) is a widely used clinician-rated measure of depressive severity. Empirical support for the factor structure of the MADRS is mixed; further, the comparison of MADRS scores within and between patients requires the demonstration of consistent instrument properties. The objective of the current investigation was to evaluate MADRS factor structure as well as MADRS factorial invariance across time and gender. The MADRS was administered to 821 depressed outpatients participating in a large-scale effectiveness study of combined pharmacotherapy and psychotherapy for depression. Treatment outcome did not differ across treatment groups. Factor structure and invariance was evaluated via confirmatory factor analysis. A four-factor model consisting of Sadness, Negative Thoughts, Detachment and Neurovegetative symptoms demonstrated a good fit to the data. This four-factor structure was invariant across time and gender. A hierarchical model, in which these four factors served as indicators of a general depression factor, was also supported. A limitation of the current study is the lack of comprehensive characterization of patient clinical features; results need to be replicated in more severely depressed or treatment refractory patients. Overall, evidence supported the use of the MADRS total score as well as subscales focused on affective, cognitive, social and somatic aspects of depression in male and female outpatients. PMID:24038301

  7. Two self-rating scales for depression in Hmong refugees: assessment in clinical and nonclinical samples.

    PubMed

    Westermeyer, J

    1986-01-01

    An exploratory cross-cultural study was undertaken of two widely used self-rating scales: the Zung and the Depression Scale on the 90 Item Symptom Checklist, or SCL-Depression. Both scales were translated into Hmong and tested in two samples of Hmong refugees in the U.S.A. One sample (n = 86) consisted of a field survey of all Hmong people living in Minnesota. Of the 86, 15 sought treatment and were diagnosed as having major depression during the year following their self rating, so that a comparison of patients' scores with nonpatients' scores was possible. The other sample consisted of another 51 Hmong psychiatric patients with major depression. This second group was also assessed by four psychiatric rating scales (i.e. Hamilton Depression Scale, brief Psychiatric Rating Scale, Inpatient Multidimensional Rating Scale, and Nurse's Observation Scale for Inpatient Evaluation) and two measures of treatment intensity (i.e. number of visits, duration of treatment). In the general Hmong population (n = 86), both self-rating scales were highly intercorrelated, and strongly associated with patient status. In the patient sample (n = 51), only the SCL-Depression showed any correlations with psychiatric rating scales or with treatment variables. This is contrary to the anticipated outcome, as it had been expected that the Zung would perform better than the SCL-Depression. In addition, duration of treatment was inversely correlated with the SCL-Depression, also opposite to our prediction. Probable causes for these unexpected results are presented. An item analysis was undertaken, comparing 71 Hmong survey subjects who were not treated for depression with 51 Hmong psychiatric patients who were treated for depression. Most Zung and SCL-Depression items showed significantly higher symptom levels in the depressed patients. However, non-depressed controls unexpectedly reported significantly higher symptom levels on certain items. No significant differences were observed on several

  8. Depression Rating Scales in Parkinson’s Disease: Critique and Recommendations

    PubMed Central

    Schrag, Anette; Barone, Paolo; Brown, Richard G.; Leentjens, Albert F.G.; McDonald, William M.; Starkstein, Sergio; Weintraub, Daniel; Poewe, Werner; Rascol, Olivier; Sampaio, Cristina; Stebbins, Glenn T.; Goetz, Christopher G.

    2007-01-01

    Depression is a common comorbid condition in Parkinson’s disease (PD) and a major contributor to poor quality of life and disability. However, depression can be difficult to assess in patients with PD due to overlapping symptoms and difficulties in the assessment of depression in cognitively impaired patients. As several rating scales have been used to assess depression in PD (dPD), the Movement Disorder Society commissioned a task force to assess their clinimetric properties and make clinical recommendations regarding their use. A systematic literature review was conducted to explore the use of depression scales in PD and determine which scales should be selected for this review. The scales reviewed were the Beck Depression Inventory (BDI), Hamilton Depression Scale (Ham-D), Hospital Anxiety and Depression Scale (HADS), Zung Self-Rating Depression Scale (SDS), Geriatric Depression Scale (GDS), Montgomery-As-berg Depression Rating Scale (MADRS), Unified Parkinson’s Disease Rating Scale (UPDRS) Part I, Cornell Scale for the Assessment of Depression in Dementia (CSDD), and the Center for Epidemiologic Studies Depression Scale (CES-D). Seven clinical researchers with clinical and research experience in the assessment of dPD were assigned to review the scales using a structured format. The most appropriate scale is dependent on the clinical or research goal. However, observer-rated scales are preferred if the study or clinical situation permits. For screening purposes, the HAM-D, BDI, HADS, MADRS, and GDS are valid in dPD. The CES-D and CSDD are alternative instruments that need validation in dPD. For measurement of severity of depressive symptoms, the Ham-D, MADRS, BDI, and SDS scales are recommended. Further studies are needed to validate the CSDD, which could be particularly useful for the assessment of severity of dPD in patients with comorbid dementia. To account for overlapping motor and nonmotor symptoms of depression, adjusted instrument cutoff scores may

  9. Dimensional structure of the Hamilton Depression Rating Scale in patients with obsessive-compulsive disorder.

    PubMed

    Moritz, Steffen; Meier, Beat; Hand, Iver; Schick, Mildred; Jahn, Holger

    2004-02-15

    Comorbid depression is frequent in obsessive-compulsive disorder (OCD) and is acknowledged as a major confound in biological and neurocognitive investigations in OCD. The aim of the present study was to assess the distribution of depressive symptoms in a large OCD sample (n=162) and to analyze the dimensional structure of the Hamilton Depression Rating Scale (HDRS) in OCD. Major depressive disorder according to DSM-IV criteria was apparent in approximately one third of the patients. Frequent symptoms were depressed mood, reduced ability to work, anxiety symptoms and guilt feelings. HDRS scores were submitted to a varimax-rotated factor analysis. In accordance with studies conducted with depressed samples, multi-dimensional solutions suggesting three to six factors emerged. Subsequent confirmatory factor analysis revealed satisfactory fit indices for a four-factorial solution comprising core depressive symptoms, sleep disturbance, anxiety and gastrointestinal problems. Aggression-related obsessions as well as the overall severity of obsessions were related to core depressive symptoms. Anxiety symptoms were associated with excessive rituals. Greater recognition of depressive sub-components may help to raise the replicability of empirical findings in OCD research as there is evidence from both depression and OCD samples that distinct depressive syndromes have different biological correlates.

  10. Depression

    MedlinePlus

    ... make negative thinking worse. previous continue Depression Can Go Unrecognized People with depression may not realize they ... themselves or who have eating disorders or who go through extreme mood changes may have unrecognized depression. ...

  11. Depression

    MedlinePlus

    ... The depression generally lifts during spring and summer. Bipolar disorder is different from depression but is included in this list is because someone with bipolar disorder experiences episodes of extreme low moods (depression). But ...

  12. Childhood Depression Subscales Using Repeated Sessions on Children's Depression Rating Scale – Revised (CDRS-R) Scores

    PubMed Central

    Bernstein, Ira; Trivedi, Madhukar; Mayes, Taryn; Kennard, Betsy; Emslie, Graham

    2014-01-01

    Abstract Background: Although acute treatments have been shown to be effective in treating early-onset depression, only one-third or thereabouts reach a remission within 3 months. Unfortunately, delayed time to remission in early-onset depression leads to poorer therapeutic outcomes. Clearly, there is a need to identify, diagnose, and provide effective treatment of a depressed patient quickly. A sophisticated understanding of depression subscales and their change over time with treatment could enhance pathways to individualized treatment approaches for childhood depression. Objective: Previous studies have found that the clinician-measured instrument, Children's Depression Rating Scale-Revised (CDRS-R) measures multiple subscales (or components) of depression. The aim of this study was to see how these subscales may change over the course of a 12-week study. This knowledge will help determine if dimensions/subscales of childhood depression (paralleling the adult literature) using the subscales derived from factor analysis procedure is useful. Methods: We examined two clinical trials in which youth (n=234) with major depressive disorder (MDD) were treated openly with fluoxetine for eight sessions spread over 12 weeks. The CDRS-R was completed based on clinician interviews with parent and child at each session. Classical test theory and component analysis with associated parallel analysis (oblique rotation) were conducted on each week's scores. Results: Although more factors were needed for the baseline and first two therapy sessions, a two-factor solution sufficed thereafter. Depressed facial affect, listless speech, and hypoactivity best defined Factor I, whereas sleep problems, appetite disturbance, physical symptoms, irritability, guilt, and weeping best defined Factor II. All other symptoms cross-loaded almost equally on the two factors. The scale's reliability (internal consistency) improved from baseline to exit sessions (α=0.65–0.91). As a result, the

  13. Tectonic Windows Reveal Off-axis Volcanic and Hydrothermal Activity and Along-strike Variations in Eruption Effusion Rates

    NASA Astrophysics Data System (ADS)

    MacDonald, K. C.

    2005-12-01

    Alvin transects of faulted escarpments 50-500m high provide tectonic windows to investigate the top 500m of oceanic crustal structure and lava stratigraphy. The Alvin archives were used to review dives from the East Pacific Rise, the Mid-Atlantic Ridge, the Juan de Fuca Ridge, the Blanco Trough, Cayman Trough and the Galapagos Spreading Center. A spreading rate dependence in lava morphology based solely on areal coverage(Bonatti and Harrison, 1988) was confirmed in scarp transects: mostly pillow lavas at slow spreading rates and sheet flows/lobate flows at faster spreading rates. More interestingly; there is a systematic variation within first, second and third order segments on intermediate and fast-spreading centers such that sheet/lobate flows dominate at segment centers and pillow flows and lava domes are more common at segment ends. This confirms earlier studies which were based on areal coverage (White et al, 2000, 2002, Soule et al 2005). This suggests higher eruption effusion rates and perhaps higher magma pressure and lower magma viscosity at segment centers relative to segment ends. This has important implications for the relationship between segmentation, magma supply, volcanism and hydrothermal activity (Haymon and White 2005). A conundrum remains; based on areal photographic surveys, why are pillow lavas so much more common off-axis than on-axis for intermediate to fast-spreading ridges? If there is an eruption cycle in which sheeted and lobate flows dominate early on, and pillow lavas dominate the waning stages of eruption (e.g. Ballard et al 1979), then more pillow lavas should be seen on axis than are seen on-axis in either areal or transect data. Another explanation is that pillow lavas off-axis are primarily produced by off-axis eruptions (except near segment ends, they may also occur as the pillowed terminations of channeled sheet and lobate flows; the association with channels will make this obvious.) Off-axis volcanism is also indicated by a

  14. Difference in the binocular rivalry rate between depressive episodes and remission.

    PubMed

    Jia, Ting; Ye, Xing; Wei, Qiang; Xie, Wen; Cai, Chunlan; Mu, Jingjing; Dong, Yi; Hu, Panpan; Hu, Xinglong; Tian, Yanghua; Wang, Kai

    2015-11-01

    Binocular rivalry refers to a phenomenon in which, when different images are presented to each eye simultaneously, perception alternates spontaneously between monocular views rather than being a superposition of the two images. Recently, the involvement of serotonin systems has been reported to be related to the phenomenon. There is abundant evidence for abnormalities of the serotonin systems in depression and the antidepressants that enhance 5-HT transmission, which in turn improves mood and behavior. However, the available data with respect to rivalry rates in depression are less clear. Therefore, we aimed to explore whether perceptual rivalry was affected by a dysfunctional serotonin system in patients with depression and whether there was a rivalry rate difference between episode and remission states in depression patients. Twenty-eight patients with depression and 30 healthy controls were recruited in the study. We assessed the rivalry rate and the 17-item Hamilton Depression Rating Scale (HAMD) in patients with depression during clinical episode and remission states. The results suggested that alternation rates for patients during episodes were significantly slower than during remission and than in healthy controls. Also, alternation rates for patients during remission were slower than in healthy controls. These results may provide further clues to serotonergic neural systems contributing to the dynamics of perception rivalry and may foster enlightenment regarding the field of binocular rivalry in psychiatric disorders other than bipolar disorder. PMID:26247392

  15. Heart Rate Variability and the Efficacy of Biofeedback in Heroin Users with Depressive Symptoms

    PubMed Central

    Lin, I-Mei; Ko, Jiun-Min; Fan, Sheng-Yu; Yen, Cheng-Fang

    2016-01-01

    Objective Low heart rate variability (HRV) has been confirmed in heroin users, but the effects of heart-rate-variability–biofeedback in heroin users remain unknown. This study examined (1) correlations between depression and HRV indices; (2) group differences in HRV indices among a heroin-user group, a group with major depressive disorder but no heroin use, and healthy controls; and (3) the effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiratory rates within the heroin group. Methods All participants completed a depression questionnaire and underwent electrocardiogram measurements, and group differences in baseline HRV indices were examined. The heroin group underwent electrocardiogram and respiration rate measurements at baseline, during a depressive condition, and during a happiness condition, before and after which they took part in the heart-rate-variability–biofeedback program. The effects of heart-rate-variability–biofeedback on depressive symptoms, HRV indices, and respiration rates were examined. Results There was a negative correlation between depression and high frequency of HRV, and a positive correlation between depression and low frequency to high frequency ratio of HRV. The heroin group had a lower overall and high frequency of HRV, and a higher low frequency/high frequency ratio than healthy controls. The heart-rate-variability–biofeedback intervention increased HRV indices and decreased respiratory rates from pre-intervention to post-intervention. Conclusion Reduced parasympathetic and increased sympathetic activations were found in heroin users. Heart-rate-variability–biofeedback was an effective non-pharmacological intervention to restore autonomic balance. PMID:27121428

  16. Toward continuous quantification of lava extrusion rate: Results from the multidisciplinary analysis of the 2 January 2010 eruption of Piton de la Fournaise volcano, La Réunion.

    NASA Astrophysics Data System (ADS)

    Hibert, Clement; Mangeney, Anne; Polacci, Margherita; Di Muro, Andrea; Vergniolle, Sylvie; Ferrazzini, Valérie; Peltier, Aline; Taisne, Benoit; Burton, Mike; Dewez, Thomas; Grandjean, Gilles; Dupont, Aurélien; Staudacher, Thomas; Brenguier, Florent; Kowalski, Philippe; Boissier, Patrice; Catherine, Philippe; Lauret, Frédéric

    2016-04-01

    The dynamics of the 2-12 January 2010 effusive eruption at Piton de la Fournaise volcano were examined through seismic and infrasound records, time-lapse photography, SO2 flux measurements, deformation data, and direct observations. Digital elevation models were constructed for four periods of the eruption, thus providing an assessment of the temporal evolution of the morphology, the volume and the extrusion rate of the lava flow. These data were compared to the continuous recording of the seismic and infrasonic waves, and a linear relationship was found between the seismic energy of the tremor and the lava extrusion rate. This relationship is supported by data from three other summit eruptions of Piton de la Fournaise and gives total volume and average lava extrusion rate in good agreement with previous studies. We can therefore provide an estimate of the lava extrusion rate for the January 2010 eruption with a very high temporal resolution. We found an average lava extrusion rate of 2.4 m3.s-1 with a peak of 106.6 m3.s-1 during the initial lava fountaining phase. We use the inferred average lava extrusion rate during the lava fountaining phase (30.23 m3.s-1) to estimate the value of the initial overpressure in the magma reservoir, which we found to range from 3.7×106 Pa to 5.9×106 Pa. Finally, based on the estimated initial overpressure, the volume of magma expelled during the lava fountaining phase and geodetic data, we inferred the volume of the magma reservoir using a simple Mogi model, between 0.25 km3 and 0.54 km3, which is in good agreement with previous studies. The multidisciplinary analysis presented in our study sheds light on crucial qualitative and quantitative relations between eruption dynamics, seismic and infrasonic signals, and especially on the direct link between the lava extrusion rate and the seismic energy of the volcanic tremor. If this relationship is confirmed for other eruptions, generalization of its use will lead to a better

  17. Comparison Between the Montgomery-Asberg Depression Rating Scale–Self and the Beck Depression Inventory II in Primary Care

    PubMed Central

    Nejati, Shabnam; Larsson, Maria E. H.; Petersson, Eva-Lisa; Westman, Jeanette; Ariai, Nashmil; Kivi, Marie; Eriksson, Maria; Eggertsen, Robert; Hange, Dominique; Baigi, Amir; Björkelund, Cecilia

    2015-01-01

    Objective: The Montgomery-Asberg Depression Rating Scale–Self (MADRS-S) and the Beck Depression Inventory II (BDI-II) are commonly used self-assessment instruments for screening and diagnosis of depression. The BDI-II has 21 items and the MADRS-S has 9 items. These instruments have been tested with psychiatric inpatients but not in outpatient primary care, where most patients with symptoms of depression initially seek treatment. The purpose of this study was to compare these 2 instruments in the primary care setting. Method: Data were collected from 2 primary care randomized controlled trials that were performed from 2010 to 2013 in Sweden: the Primary Care Self-Assessment MADRS-S Study and Primary Care Internet-Based Cognitive Behavioral Therapy Study. There were 146 patients (73 patients each from both trials) who had newly diagnosed mild or moderate depression (per DSM-IV recommendations) and who had assessment with both the MADRS-S and BDI-II at primary care centers. Comparability and reliability of the instruments were estimated by Pearson product moment correlation and Cronbach α. Results: A good correlation was observed between the 2 instruments: 0.66 and 0.62 in the 2 study cohorts. The reliability within the 2 study cohorts was good for both MADRS-S (Cronbach α: 0.76 for both cohorts) and BDI-II items (Cronbach α: 0.88 and 0.85). Conclusions: The 2 instruments showed good comparability and reliability for low, middle, and high total depression scores. The MADRS-S may be used as a rapid, easily administered, and inexpensive tool in primary care and has results comparable to the BDI-II in all domains. PMID:26644958

  18. The Inventory Of Depressive Symptomatology (IDS-C(28)) is more sensitive to changes in depressive symptomatology than the Hamilton Depression Rating Scale (HAMD(17)) in patients with mild major, minor or subsyndromal depression.

    PubMed

    Helmreich, Isabella; Wagner, Stefanie; Mergl, Roland; Allgaier, Antje-Kathrin; Hautzinger, Martin; Henkel, Verena; Hegerl, Ulrich; Tadić, André

    2011-08-01

    Depression rating scales play a decisive role in the assessment of the severity of depression and the evaluation of the efficacy of antidepressant treatments. The Hamilton Depression Rating Scale (HAMD) is regarded as the 'gold standard'; nevertheless, studies suggest that the Inventory of Depressive Symptomatology (IDS) is more sensitive to detect symptom changes. The aim of the present study was to investigate whether the IDS is more sensitive in detecting changes in depression symptoms in patients with mild major, minor or subsyndromal depression (MIND). Biweekly IDS-C(28) and HAMD(17) data from 340 patients of a 10-week randomized, placebo-controlled trial comparing the effectiveness of sertraline and cognitive-behavioural therapy in patients with MIND were analysed. We investigated sensitivity to change for both scales (1) from assessment-to-assessment, (2) in relation to depression severity level, and (3) in relation to DSM-IV depression criterion symptoms. The IDS-C(28) was more sensitive in detecting changes in depression symptomatology over the treatment course as well as for different severity levels, especially in patients with a low depression severity. It assesses the DSM-IV criteria more thoroughly, is better able to track the change of cognitive symptoms and to identify residual symptoms. Both scales are well able to assess depressive symptomatology. However, the IDS-C(28) surpasses the HAMD(17) in detecting small changes especially in the core symptoms of depression. This is important for an optimal treatment by capturing early improvements, enabling prompt reactions and detecting residual symptoms.

  19. The genetic consequences of fluctuating inbreeding depression and the evolution of plant selfing rates.

    PubMed

    Porcher, E; Kelly, J K; Cheptou, P-O; Eckert, C G; Johnston, M O; Kalisz, S

    2009-04-01

    The magnitude of inbreeding depression, a central parameter in the evolution of plant mating systems, can vary depending on environmental conditions. However, the underlying genetic mechanisms causing environmental fluctuations in inbreeding depression, and the consequences of this variation for the evolution of self-fertilization, have been little studied. Here, we consider temporal fluctuations of the selection coefficient in an explicit genetic model of inbreeding depression. We show that substantial variance in inbreeding depression can be generated at equilibrium by fluctuating selection, although the simulated variance tends to be lower than has been measured in experimental studies. Our simulations also reveal that purging of deleterious mutations does not depend on the variance in their selection coefficient. Finally, an evolutionary analysis shows that, in contrast to previous theoretical approaches, intermediate selfing rates are never evolutionarily stable when the variation in inbreeding depression is due to fluctuations in the selection coefficient on deleterious mutations.

  20. Decoupled crystallization and eruption histories of the rhyolite magmatic system at Tarawera volcano revealed by zircon ages and growth rates

    NASA Astrophysics Data System (ADS)

    Storm, Sonja; Shane, Phil; Schmitt, Axel K.; Lindsay, Jan M.

    2012-03-01

    We obtained U-Th disequilibrium age data on zircons from each of the four rhyolite eruptions that built Tarawera volcano in the last 22 ka within the Okataina Volcanic Center (OVC), caldera, New Zealand. Secondary ion mass spectrometry analyses on unpolished euhedral crystal faces that lack resorption features show that crystal growth variously terminated from near-eruption age to ~100 ka prior to eruption. Age-depth profiling of crystals reveals long periods of continuous (~34 ka) and discontinuous growth (~90 ka). Growth hiatuses of up to ~40 ka duration occur, but do not all relate to obvious resorption surfaces. Age differences up to similar magnitude are found on opposing faces of some crystals suggesting episodes of partial exposure to melts. These features are best explained by periodic, complete, or partial, sub-solidus storage and/or inclusion in larger crystal phases, followed by rapid liberation prior to eruption. This is supported by high abundances of U and Th (~500 - >2,000 ppm) in some zircons consistent with periods of high crystallinity (>70%) in the magmatic system, based on crystal/melt partitioning. Contemporaneous but contrasting rim-ward trends of these elements within crystals, even in the same lava hand sample, require synchronous growth in separate melt bodies and little connectivity within the system, but also significant crystal transport and mixing prior to eruption. Many crystals record continuity of growth through the preceding ~60 ka OVC caldera-collapse and subsequent eruptions from Tarawera. This demonstrates a decoupling between eruption triggers, such as shallow crustal extension and mafic intrusion, and the crystallization state of the OVC silicic magmatic system. The data highlights the need to distinguish between the time for accumulation of eruptible magma and the long-term magma residence time based on the age of crystals with high closure temperatures, when assessing the potential for catastrophic eruptions.

  1. Interaction of depressive symptoms and smoking abstinence on delay discounting rates.

    PubMed

    Weidberg, Sara; García-Rodríguez, Olaya; Yoon, Jin H; Secades-Villa, Roberto

    2015-12-01

    Delay discounting and depressive symptomatology have strong connections with smoking. However, few studies have examined interactions across delay discounting, depressive symptoms, and smoking status. The primary goal of this secondary analysis was to assess the interrelations across these 3 variables among treatment-seeking smokers. Delay discounting and depressive symptoms were assessed in 95 smokers enrolled in a clinical trial for smoking cessation at intake and 6-month follow-up. Participants with and without depressive symptoms did not differ in their discounting rates neither at intake nor at 6-month follow-up. However, delay discounting was significantly lower among abstainers at 6-month follow-up, and changes in discounting associated with smoking status were more pronounced among participants with depressive symptoms. These results clarify the relationship between delay discounting and depressive symptoms among current and former smokers and suggest that the association between smoking abstinence and lower delay discounting is significantly greater among individuals with depressive symptoms versus those who do not have depressive symptomatology.

  2. Base Rates of Depressive Symptoms in Patients with Coronary Heart Disease: An Individual Symptom Analysis

    PubMed Central

    Kohlmann, Sebastian; Gierk, Benjamin; Murray, Alexandra M.; Scholl, Arne; Lehmann, Marco; Löwe, Bernd

    2016-01-01

    Background Major depression is common in coronary heart disease (CHD) but challenging to diagnose. Instead of focusing on the overall diagnosis of depression, base rates of depressive symptoms could facilitate screening and management of psychopathology in CHD. The present study investigates the frequency of individual depressive symptoms in CHD and their impact on cardiac and subjective health. Methods In total, 1337 in- and outpatients with CHD were screened for depressive symptoms with the Patient Health Questionnaire-9 (PHQ-9) at three different cardiac treatment sites. Tables stratified by age and gender were designed to illustrate base rates of depressive symptoms. Multiple regression analyses adjusted for sociodemographic and clinical data were conducted to test associations between individual depressive symptoms and quality of life as well impairment caused angina pectoris and dyspnea. Results During the last 14 days, more than half of patients reported a loss of energy (74.9%, 95% Confidence Interval (CI): 70.6–79.2), sleeping problems (69.4%, 95% CI: 64.9–74.0), loss of interest (55.7%, 95% CI: 50.8–60.7). In contrast, psychomotor change (25.6%, 95%CI: 21.3–30.0), feelings of failure (21.9%, 95%CI: 17.7–26.0), suicidal ideations (14.1%, 95%CI: 10.7–17.6) were less frequently reported. Depending on the outcome, only particular depressive symptoms were highly associated with low quality of life and impairment caused by angina pectoris and dyspnea. Loss of energy was the only depressive symptom that reliably predicted all three outcomes. Conclusions Depressive symptoms in CHD are frequent but vary widely in terms of frequency. Findings underline the differential effects of individual depressive symptoms on cardiac health. Presented base rates of depressive symptoms offer clinicians a new way to judge the severity of individual depressive symptoms and to communicate individual PHQ-9 profiles with patients with respect to gender, age, cardiac

  3. Gravity current model of the volumetric growth of volcanic clouds: remote assessment with satellite imagery and estimation of mass eruption rate

    NASA Astrophysics Data System (ADS)

    Pouget, S.; Bursik, M. I.; Sparks, R. S.; Hogg, A. J.; Johnson, C. G.; Singh, T.; Pavolonis, M. J.

    2013-12-01

    The eruption of Eyjafjallajökull, Iceland in April and May, 2010, brought to light the hazards of airborne volcanic ash and the importance of being able to estimate the concentration of ash with time. This can be done using Volcanic Ash Transport and Dispersion models (VATD). These models require Eruption Source Parameters (ESP) such as the mass eruption rate (MER), as input. MER can be estimated from volumetric flux assuming gravity current behavior of the atmospheric intrusion. We used a gravity current model for the umbrella cloud and downwind plume in which the predominantly horizontal spreading through the atmosphere is driven by buoyancy forces and wind drag. Ash is advected by these atmospheric motions and settles out relatively slowly under the action of gravity. Given the importance of knowing ESP for VATD, we explored the use of the gravity current model applied to satellite imagery, using the geometric characteristics of ash clouds. To test the gravity current model on the use of satellite imagery, we estimated ESP from five well-studied and well-characterized historical eruptions: Mount St. Helens, 1980; Pinatubo, 1991, Redoubt, 1990; Hekla, 2000 and Eyjafjallajökull, 2010. These tests show that the methodologies yield results comparable to currently accepted methodologies of ESP estimation. We then applied the methodology to umbrella clouds produced by the eruptions of Okmok, 12 July 2008, and Sarychev Peak, 12 June 2009, and to the downwind plume produced by the eruptions of Hekla, 2000; Kliuchevsko'i, 1 October 1994; Kasatochi 7-8 August 2008 and Bezymianny, 1 September 2012; none of which had previous estimates of MER.

  4. Revised stratigraphy and eruption rates of Ceboruco stratovolcano and surrounding monogenetic vents (Nayarit, Mexico) from historical documents and new radiocarbon dates

    NASA Astrophysics Data System (ADS)

    Sieron, Katrin; Siebe, Claus

    2008-09-01

    More than a dozen new radiocarbon dates reconstruct the eruptive history of Ceboruco volcano. Six of these further constrain previous results for the important plinian Jala eruption, which occurred near 1060 ± 55 yr BP. A calibrated radiocarbon age of AD 990-1020 was obtained as best overlap range for all samples. Pottery fragments found directly underneath the pumice deposit indicate that this area was inhabited by human populations that witnessed the eruption. This age therefore represents an important time marker in the prehistory of this region, because an area of > 560 km2 was devastated and covered by a thickness of > 50 cm of pumice and ash fallout. After the prominent Jala eruption (VEI = 6), at least seven major lava flows and several smaller domes were issued from Ceboruco's crater. Analysis of historical documents allows us to conclude that most of these eruptions took place well before the arrival of the Spanish conquerors to this area in 1528. Ceboruco's last historic eruption (1870-1872) produced a ca. 7 km long viscous dacite lava flow. Its emplacement was accompanied by block-and-ash flow activity and deposition of ash fallout. Because a repeat of such an eruption in the future would seriously endanger the nearby population and disrupt important life-lines, a detailed discussion of eyewitness accounts and other documents, including drawings and paintings is provided. Some of these materials are made available to the broader public for the first time in the present article. Several surrounding monogenetic vents were previously dated by others using the K-Ar and the Ar-Ar methods. Because these dating methods are often not suitable for very young rocks, we also dated several Holocene monogenetic vents by the radiocarbon method. These dates together with geologic mapping allowed calculating eruption rates and recurrence intervals of different types of eruptions. Accordingly, an andesite/dacite lava flow (accompanied by block-and-ash flow activity) was

  5. Prevalence Rate and Risk Factors of Depression in Outpatients with Premature Ejaculation

    PubMed Central

    Zhang, Xiansheng; Liu, Jishuang; Xia, Lei; Yang, Jiajia; Hao, Zongyao; Zhou, Jun; Liang, Chaozhao

    2013-01-01

    The purpose of this study is to investigate the prevalence rate and risk factors of depression in outpatients who were diagnosed with PE. Therefore, between September 2009 and September 2011, 1801 outpatients at andrology clinics were enrolled and consented to participate in our survey by completed a verbal questionnaire. It included the following: (1) demographic data (e.g., age, body mass index), (2) PE duration, medical history, and sexual history, (3) self-estimated intravaginal ejaculatory latency times, (4) the Zung Self-rating Depression Scale (SDS), and (5) the National Institute of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and (6) the International Index of Erectile Function (IIEF-5). The results showed that a total of 1,206 patients were diagnosed with PE. The prevalence rate of depression in these PE patients was 26.78%. Depression was associated with PE duration, NIH-CPSI score, and IIEF-5 score. Risk factors for depression specifically included PE durations for 13–24, 25–60, or ≥61 months, CPSI scores of 15–30 or ≥31, and IIEF-5 scores <22. These findings suggested that several associated factors (PE duration, CPSI scores, and IIEF-5 scores) were the risk factors of depression in men with PE. PMID:23844361

  6. Using effort-reward imbalance theory to understand high rates of depression and anxiety among clergy.

    PubMed

    Proeschold-Bell, Rae Jean; Miles, Andrew; Toth, Matthew; Adams, Christopher; Smith, Bruce W; Toole, David

    2013-12-01

    The clergy occupation is unique in its combination of role strains and higher calling, putting clergy mental health at risk. We surveyed all United Methodist clergy in North Carolina, and 95% (n = 1,726) responded, with 38% responding via phone interview. We compared clergy phone interview depression rates, assessed using the Patient Health Questionnaire (PHQ-9), to those of in-person interviews in a representative United States sample that also used the PHQ-9. The clergy depression prevalence was 8.7%, significantly higher than the 5.5% rate of the national sample. We used logistic regression to explain depression, and also anxiety, assessed using the Hospital Anxiety and Depression Scale. As hypothesized by effort-reward imbalance theory, several extrinsic demands (job stress, life unpredictability) and intrinsic demands (guilt about not doing enough work, doubting one's call to ministry) significantly predicted depression and anxiety, as did rewards such as ministry satisfaction and lack of financial stress. The high rate of clergy depression signals the need for preventive policies and programs for clergy. The extrinsic and intrinsic demands and rewards suggest specific actions to improve clergy mental health.

  7. The Montgomery Asberg and the Hamilton ratings of depression: a comparison of measures.

    PubMed

    Carmody, Thomas J; Rush, A John; Bernstein, Ira; Warden, Diane; Brannan, Stephen; Burnham, Daniel; Woo, Ada; Trivedi, Madhukar H

    2006-12-01

    The 17-item Hamilton Rating Scale for Depression (HRSD(17)) and the Montgomery Asberg Depression Rating Scale (MADRS) are two widely used clinician-rated symptom scales. A 6-item version of the HRSD (HRSD(6)) was created by Bech to address the psychometric limitations of the HRSD(17). The psychometric properties of these measures were compared using classical test theory (CTT) and item response theory (IRT) methods. IRT methods were used to equate total scores on any two scales. Data from two distinctly different outpatient studies of nonpsychotic major depression: a 12-month study of highly treatment-resistant patients (n=233) and an 8-week acute phase drug treatment trial (n=985) were used for robustness of results. MADRS and HRSD(6) items generally contributed more to the measurement of depression than HRSD(17) items as shown by higher item-total correlations and higher IRT slope parameters. The MADRS and HRSD(6) were unifactorial while the HRSD(17) contained 2 factors. The MADRS showed about twice the precision in estimating depression as either the HRSD(17) or HRSD(6) for average severity of depression. An HRSD(17) of 7 corresponded to an 8 or 9 on the MADRS and 4 on the HRSD(6). The MADRS would be superior to the HRSD(17) in the conduct of clinical trials.

  8. Comparison of two self-rating scales to detect depression: HADS and PHQ-9

    PubMed Central

    Hansson, Maja; Chotai, Jayanti; Nordstöm, Annika; Bodlund, Owe

    2009-01-01

    Background More than half of patients with depression go undetected. Self-rating scales can be useful in screening for depression, and measuring severity and treatment outcome. Aim This study compares the Hospital Anxiety and Depression Scale (HADS) and the Patient Health Questionnaire (PHQ-9) with regard to their psychometric properties, and investigates their agreement at different cut-off scores. Method Swedish primary care patients and psychiatric outpatients (n = 737) who reported symptoms of depression completed the self-rating scales. Data were collected from 2006 to 2007. Analyses with respect to internal consistency, factor analysis, and agreement (Cohen's κ) at recommended cut-offs were performed. Results Both scales had high internal consistency (α = 0.9) and stable factor structures. Using severity cut-offs, the PHQ-9 (≥5) diagnosed about 30% more patients than the HADS depression subscale (HADS-D; ≥8). They recognised the same prevalence of mild and moderate depression, but differed in relation to severe depression. When comparing recommended screening cut-offs, HADS-D ≥11 (33.5% of participants) and PHQ-9 ≥10 (65.9%) agreement was low (κ = 0.35). Using the lower recommended cut-off in the HADS-D (≥8), agreement with PHQ-9 ≥10 was moderate (κ = 0.52). The highest agreement (κ = 0.56) was found comparing HADS-D ≥8 with PHQ-9 ≥12. This also equalised the prevalence of depression found by the scales. Conclusion The HADS and PHQ-9 are both quick and reliable. The HADS has the advantage of evaluating both depression and anxiety, and the PHQ-9 of being strictly based upon the Diagnostic and Statistical Manual of Mental Disorders. The agreement between the scales at the best suitable cut-off is moderate, although the identified prevalence was similar. This indicates that the scales do not fully identify the same cases. This difference needs to be further explored. PMID:19761655

  9. Standardized clinical outcome rating scale for depression for use in clinical practice.

    PubMed

    Zimmerman, Mark; Posternak, Michael A; Chelminski, Iwona; Friedman, Michael

    2005-01-01

    The integration of research into clinical practice to conduct effectiveness studies faces multiple obstacles. One obstacle is the burden of completing research measures of outcome. A simple, reliable, and valid measure that could be rated at every visit, incorporated into a clinician's progress note, and reflect the DSM-IV definition of a major depressive episode (including partial and full remission from the episode) would enhance the ability to conduct effectiveness research. The goal of the present study was to examine the reliability and validity of such a measure. Three hundred and three psychiatric outpatients who were being treated for a DSM-IV major depressive episode were rated on the Standardized Clinical Outcome Rating for Depression (SCOR-D), 17-item Hamilton Rating Scale for Depression, Montgomery-Asberg Depression Rating Scale, and the Global Assessment of Functioning. We examined the correlation between the SCOR-D and the other measures, and conducted an analyses of variance to compare mean values on these measures for each rating point on the SCOR-D. The inter-rater reliability of the SCOR-D dimensional ratings and categorical determination of remission were high. The SCOR-D was highly correlated with the other scales, and there were significant differences on the other measures of depression severity between each adjacent rating level of the SCOR-D. The SCOR-D is a brief standardized outcome measure linked to the DSM-IV approach toward defining remission that can be incorporated into routine clinical practice without adding undue burden to the treating clinician with some evidence of reliability and validity. This measure could make it more feasible to conduct effectiveness studies in clinical practice.

  10. Toward continuous quantification of lava extrusion rate: Results from the multidisciplinary analysis of the 2 January 2010 eruption of Piton de la Fournaise volcano, La Réunion

    NASA Astrophysics Data System (ADS)

    Hibert, C.; Mangeney, A.; Polacci, M.; Muro, A. Di; Vergniolle, S.; Ferrazzini, V.; Peltier, A.; Taisne, B.; Burton, M.; Dewez, T.; Grandjean, G.; Dupont, A.; Staudacher, T.; Brenguier, F.; Kowalski, P.; Boissier, P.; Catherine, P.; Lauret, F.

    2015-05-01

    The dynamics of the 2-12 January 2010 effusive eruption at Piton de la Fournaise volcano were examined through seismic and infrasound records, time-lapse photography, SO2 flux measurements, deformation data, and direct observations. Digital elevation models were constructed for four periods of the eruption, thus providing an assessment of the temporal evolution of the morphology, the volume and the extrusion rate of the lava flow. These data were compared to the continuous recording of the seismic and infrasonic waves, and a linear relationship was found between the seismic energy of the tremor and the lava extrusion rate. This relationship is supported by data from three other summit eruptions of Piton de la Fournaise and gives total volume and average lava extrusion rate in good agreement with previous studies. We can therefore provide an estimate of the lava extrusion rate for the January 2010 eruption with a very high temporal resolution. We found an average lava extrusion rate of 2.4 m3s-1 with a peak of 106.6 m3s-1 during the initial lava fountaining phase. We use the inferred average lava extrusion rate during the lava fountaining phase (30.23 m3s-1) to estimate the value of the initial overpressure in the magma reservoir, which we found to range from 3.7×106 Pa to 5.9×106 Pa. Finally, based on the estimated initial overpressure, the volume of magma expelled during the lava fountaining phase and geodetic data, we inferred the volume of the magma reservoir using a simple Mogi model, between 0.25 km3 and 0.54 km3, which is in good agreement with previous studies.

  11. Use of digital aerophotogrammetry to determine rates of lava dome growth, Mount St. Helens, Washington, 2004-2005: Chapter 8 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Schilling, Steve P.; Thompson, Ren A.; Messerich, James A.; Iwatsubo, Eugene Y.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    Successful application of aerophotogrammetry was possible during the critical earliest parts of the eruption because we had baseline data and photogrammetric infrastructure in place before the eruption began. The vertical aerial photographs, including the DEMs and calculations derived from them, were one of the most widely used data sets collected during the 2004-5 eruption, as evidenced in numerous contributions to this volume. These data were used to construct photogeologic maps, deformation vector fields, and profiles of the evolving dome and glacier. Extruded volumes and rates proved to be critical parameters to constrain models and hypotheses of eruption dynamics and thus helped to assess volcano hazards.

  12. Dopamine, Depressive Symptoms and Decision-Making: The Relationship between Spontaneous Eyeblink Rate and Depressive Symptoms Predicts Iowa Gambling Task Performance

    PubMed Central

    Byrne, Kaileigh A.; Norris, Dominique D.; Worthy, Darrell A.

    2016-01-01

    Depressive symptomatology has been associated with alterations in decision-making, although conclusions have been mixed with depressed individuals showing impairments in some contexts, but advantages in others. The dopaminergic system may link depressive symptoms with decision-making performance. We assessed the role of striatal dopamine D2 receptor density, using spontaneous eyeblink rate, in moderating the relationship between depressive symptoms and decision-making performance in a large undergraduate sample that had not been screened for mental illness (N=104). Regression results revealed that eyeblink rate moderated the relationship between depressive symptoms and advantageous decisions on the IGT in which individuals with more depressive symptomatology and high blink rates (higher striatal dopamine D2 receptor density) performed better on the task. Computational modeling results demonstrated that depressive symptoms alone were associated with enhanced loss aversive behavior, while individuals with high blink rates and elevated depressive symptoms tended to persevere in selecting options that led to net gains (avoiding options with net losses). These findings suggest that variation in striatal dopamine D2 receptor availability in individuals with depressive symptoms may contribute to differences in decision-making behavior. PMID:26383904

  13. Depression.

    ERIC Educational Resources Information Center

    Strock, Margaret

    Approximately ten percent of the population suffers from a depressive illness each year. Although the economic cost is high, the cost in human suffering is immeasurable. To help educate the population about this disorder, this paper presents a definition of depression and its common manifestations. The symptoms that people often experience are…

  14. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression

    PubMed Central

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship. PMID:26943924

  15. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression.

    PubMed

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship.

  16. Attachment Status Affects Heart Rate Responses to Experimental Ostracism in Inpatients with Depression.

    PubMed

    De Rubeis, Jannika; Sütterlin, Stefan; Lange, Diane; Pawelzik, Markus; van Randenborgh, Annette; Victor, Daniela; Vögele, Claus

    2016-01-01

    Depression is assumed to be both a risk factor for rejection and a result of it, and as such constitutes an important factor in rejection research. Attachment theory has been applied to understand psychological disorders, such as depression, and can explain individual differences in responses to rejection. Research on autonomic nervous system activity to rejection experiences has been contradictory, with opposing strings of argumentation (activating vs. numbing). We investigated autonomic nervous system-mediated peripheral physiological responses (heart rate) to experimentally manipulated ostracism (Cyberball) in 97 depressed patients with organized (n = 52) and disorganized attachment status (n = 45). Controlling for baseline mean heart rate levels, depressed patients with disorganized attachment status responded to ostracism with significantly higher increases in heart rate than depressed patients with organized attachment status (p = .029; ηp2 = .051). These results suggest that attachment status may be a useful indicator of autonomic responses to perceived social threat, which in turn may affect the therapeutic process and the patient-therapist relationship. PMID:26943924

  17. Financial Incentives for Smoking Cessation Among Depression-Prone Pregnant and Newly Postpartum Women: Effects on Smoking Abstinence and Depression Ratings

    PubMed Central

    Lopez, Alexa A.; Skelly, Joan M.

    2015-01-01

    Introduction: We examined whether pregnant and newly postpartum smokers at risk for postpartum depression respond to an incentive-based smoking-cessation treatment and how the intervention impacts depression ratings. Methods: This study is a secondary data analysis. Participants (N = 289; data collected 2001–2013) were smokers at the start of prenatal care who participated in 4 controlled clinical trials on the efficacy of financial incentives for smoking cessation. Women were assigned either to an intervention wherein they earned vouchers exchangeable for retail items contingent on abstaining from smoking or to a control condition wherein they received vouchers of comparable value independent of smoking status. Treatments were provided antepartum through 12-weeks postpartum. Depression ratings (Beck Depression Inventory [BDI]-1A) were examined across 7 antepartum/postpartum assessments. Women who reported a history of prior depression or who had BDI scores ≥ 17 at the start of prenatal care were categorized as depression-prone (Dep+), while those meeting neither criterion were categorized as depression-negative (Dep−). Results: The intervention increased smoking abstinence independent of depression status (p < .001), and it decreased mean postpartum BDI ratings as well as the proportion of women scoring in the clinical range (≥17 and >21) compared with the control treatment (ps ≤ .05). Treatment effects on depression ratings were attributable to changes in Dep+ women. Conclusions: These results demonstrate that depression-prone pregnant and newly postpartum women respond well to this incentive-based smoking-cessation intervention in terms of achieving abstinence, and the intervention also reduces the severity of postpartum depression ratings in this at-risk population. PMID:25762756

  18. Bayesian estimation of magma supply, storage, and eruption rates using a multiphysical volcano model: Kīlauea Volcano, 2000-2012

    NASA Astrophysics Data System (ADS)

    Anderson, Kyle R.; Poland, Michael P.

    2016-08-01

    Estimating rates of magma supply to the world's volcanoes remains one of the most fundamental aims of volcanology. Yet, supply rates can be difficult to estimate even at well-monitored volcanoes, in part because observations are noisy and are usually considered independently rather than as part of a holistic system. In this work we demonstrate a technique for probabilistically estimating time-variable rates of magma supply to a volcano through probabilistic constraint on storage and eruption rates. This approach utilizes Bayesian joint inversion of diverse datasets using predictions from a multiphysical volcano model, and independent prior information derived from previous geophysical, geochemical, and geological studies. The solution to the inverse problem takes the form of a probability density function which takes into account uncertainties in observations and prior information, and which we sample using a Markov chain Monte Carlo algorithm. Applying the technique to Kīlauea Volcano, we develop a model which relates magma flow rates with deformation of the volcano's surface, sulfur dioxide emission rates, lava flow field volumes, and composition of the volcano's basaltic magma. This model accounts for effects and processes mostly neglected in previous supply rate estimates at Kīlauea, including magma compressibility, loss of sulfur to the hydrothermal system, and potential magma storage in the volcano's deep rift zones. We jointly invert data and prior information to estimate rates of supply, storage, and eruption during three recent quasi-steady-state periods at the volcano. Results shed new light on the time-variability of magma supply to Kīlauea, which we find to have increased by 35-100% between 2001 and 2006 (from 0.11-0.17 to 0.18-0.28 km3/yr), before subsequently decreasing to 0.08-0.12 km3/yr by 2012. Changes in supply rate directly impact hazard at the volcano, and were largely responsible for an increase in eruption rate of 60-150% between 2001 and

  19. Bayesian estimation of magma supply, storage, and eruption rates using a multiphysical volcano model: Kīlauea Volcano, 2000–2012

    USGS Publications Warehouse

    Anderson, Kyle R.; Poland, Michael

    2016-01-01

    Estimating rates of magma supply to the world's volcanoes remains one of the most fundamental aims of volcanology. Yet, supply rates can be difficult to estimate even at well-monitored volcanoes, in part because observations are noisy and are usually considered independently rather than as part of a holistic system. In this work we demonstrate a technique for probabilistically estimating time-variable rates of magma supply to a volcano through probabilistic constraint on storage and eruption rates. This approach utilizes Bayesian joint inversion of diverse datasets using predictions from a multiphysical volcano model, and independent prior information derived from previous geophysical, geochemical, and geological studies. The solution to the inverse problem takes the form of a probability density function which takes into account uncertainties in observations and prior information, and which we sample using a Markov chain Monte Carlo algorithm. Applying the technique to Kīlauea Volcano, we develop a model which relates magma flow rates with deformation of the volcano's surface, sulfur dioxide emission rates, lava flow field volumes, and composition of the volcano's basaltic magma. This model accounts for effects and processes mostly neglected in previous supply rate estimates at Kīlauea, including magma compressibility, loss of sulfur to the hydrothermal system, and potential magma storage in the volcano's deep rift zones. We jointly invert data and prior information to estimate rates of supply, storage, and eruption during three recent quasi-steady-state periods at the volcano. Results shed new light on the time-variability of magma supply to Kīlauea, which we find to have increased by 35–100% between 2001 and 2006 (from 0.11–0.17 to 0.18–0.28 km3/yr), before subsequently decreasing to 0.08–0.12 km3/yr by 2012. Changes in supply rate directly impact hazard at the volcano, and were largely responsible for an increase in eruption rate of 60–150% between

  20. Seasonality of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Mason, B. G.; Pyle, D. M.; Dade, W. B.; Jupp, T.

    2004-04-01

    An analysis of volcanic activity during the last three hundred years reveals that volcanic eruptions exhibit seasonality to a statistically significant degree. This remarkable pattern is observed primarily along the Pacific "Ring of Fire" and locally at some individual volcanoes. Globally, seasonal fluctuations amount to 18% of the historical average monthly eruption rate. In some regions, seasonal fluctuations amount to as much as 50% of the average eruption rate. Seasonality principally reflects the temporal distribution of the smaller, dated eruptions (volcanic explosivity index of 0-2) that dominate the eruption catalog. We suggest that the pattern of seasonality correlates with the annual Earth surface deformation that accompanies the movement of surface water mass during the annual hydrological cycle and illustrate this with respect to global models of surface deformation and regional measurements of annual sea level change. For example, seasonal peaks in the eruption rate of volcanoes in Central America, the Alaskan Peninsula, and Kamchatka coincide with periods of falling regional sea level. In Melanesia, in contrast, peak numbers of volcanic eruptions occur during months of maximal regional sea level and falling regional atmospheric pressure. We suggest that the well-documented slow deformation of Earth's surface that accompanies the annual movements of water mass from oceans to continents acts to impose a fluctuating boundary condition on volcanoes, such that volcanic eruptions tend to be concentrated during periods of local or regional surface change rather than simply being distributed randomly throughout the year. Our findings have important ramifications for volcanic risk assessment and volcanoclimate feedback mechanisms.

  1. Depression.

    PubMed

    Weissman, Myrna

    2009-04-01

    This is an invited article on how my career as an epidemiologist studying depression unfolded. The role of the Civil Rights movement in opening the PhD doors to women at Yale began my career. The unfolding of depression studies are described. These studies included a clinical trial of medication and what later was known as interpersonal psychotherapy (IPT), the first community survey of psychiatric disorder, family genetic and brain imaging studies or depression and anxiety disorders. I hope the new generation will have the wonderful opportunities I have had.

  2. Depression.

    PubMed

    Weissman, Myrna

    2009-04-01

    This is an invited article on how my career as an epidemiologist studying depression unfolded. The role of the Civil Rights movement in opening the PhD doors to women at Yale began my career. The unfolding of depression studies are described. These studies included a clinical trial of medication and what later was known as interpersonal psychotherapy (IPT), the first community survey of psychiatric disorder, family genetic and brain imaging studies or depression and anxiety disorders. I hope the new generation will have the wonderful opportunities I have had. PMID:19344866

  3. Intake Screening with the Self-Rating Depression Scale in a University Counseling Center.

    ERIC Educational Resources Information Center

    Smith, Timothy B.; Rosenstein, Ilene; Granaas, Michael M.

    2001-01-01

    Examines the psychometric properties of the Self-Rating Depression Scale (SDS) using an ethnically diverse sample of 324 counseling center clients. Results provide moderate support for the SDS. Differences across demographic groups and considerations for intake screening are discussed. (Contains 23 references.) (GCP)

  4. Depression

    MedlinePlus

    ... newborns, as well as jitteriness, difficulty feeding, and low blood sugar after delivery. However, moms who stop medications can ... a kind of antidepressant for treating depression and anxiety disorders. However, a number of research studies show ...

  5. Effusion rates, volumes and emplacement style using MODIS MIR data: the 2014-15 Holuhraun eruption (Bárðarbunga, Iceland) tracked by MIROVA

    NASA Astrophysics Data System (ADS)

    Coppola, Diego; Laiolo, Marco; Cigolini, Corrado; Barsotti, Sara; Jónasdóttir, Elin; Ripepe, Maurizio

    2016-04-01

    MIROVA (Middle InfraRed Observation of Volcanic Activity) is a new volcanic hot-spot detection system, based on the near-real time analysis of infrared data acquired by the MODIS sensor (Moderate Resolution Imaging Spectroradiometer). During the Holuhraun (Bárðarbunga) eruption, which lasted from the end of August 2014 to February 2015, MIROVA has been used to detect, locate and measure the heat radiated by the evolving lava field. After peaking during the first two week of activity, the eruption produced a slow but persistent decay of MIR-derived thermal flux, that was coupled with a gradual transition from channel- to tube-fed dominated emplacement style. This was coupled with a modification of the principal growing process of the flow field that shifted from lengthening to widening and finally to thickening. Despite the evident evolution of the emplacement style our results suggest that the decreasing trend of the thermal flux was essentially controlled by the slow reduction of the effusion rates, rather than by the increasing insulation of the flow field. In fact, we provide evidence that the changing emplacement style, from channel- to tube-fed activity , did not affected (substantially) the area of radiating lava surface, but had simply a strong impact in transporting the lava farther from the vent. This suggests that during the Holuhraun eruption, as well as during many other effusive eruptions, the MIR-derived radiant flux essentially mimic the trend of lava discharge rates, with only a minor influences due to the emplacement style.

  6. High effusion rates of the Cordón Caulle 2011-2012 eruption (Southern Andes) and their relation with the quasi-harmonic tremor

    NASA Astrophysics Data System (ADS)

    Bertin, D.; Lara, L. E.; Basualto, D.; Amigo, Á.; Cardona, C.; Franco, L.; Gil, F.; Lazo, J.

    2015-09-01

    High effusion rates of intermediate-to-high-silica lavas seem to be less uncommon than previously thought, in particular during their initial eruptive stages. In this study, we report satellite-based time-averaged discharge rates for the 2011-2012 effusive phase at Cordón Caulle, which are well correlated with the evolution of the quasi-harmonic tremor, the most significant seismic signal after the initial explosive stage. Such a correspondence could become a key method for detection of the onset of effusive phases, especially in remote and/or very cloudy areas, supplying an additional tool for effective warnings and near-real-time hazard appraisal.

  7. Depression Screening Using Daily Mental-Health Ratings from a Smartphone Application for Breast Cancer Patients

    PubMed Central

    Kim, Junetae; Lim, Sanghee; Min, Yul Ha; Shin, Yong-Wook; Lee, Byungtae; Sohn, Guiyun; Jung, Kyung Hae; Lee, Jae-Ho; Son, Byung Ho; Ahn, Sei Hyun; Shin, Soo-Yong

    2016-01-01

    Background Mobile mental-health trackers are mobile phone apps that gather self-reported mental-health ratings from users. They have received great attention from clinicians as tools to screen for depression in individual patients. While several apps that ask simple questions using face emoticons have been developed, there has been no study examining the validity of their screening performance. Objective In this study, we (1) evaluate the potential of a mobile mental-health tracker that uses three daily mental-health ratings (sleep satisfaction, mood, and anxiety) as indicators for depression, (2) discuss three approaches to data processing (ratio, average, and frequency) for generating indicator variables, and (3) examine the impact of adherence on reporting using a mobile mental-health tracker and accuracy in depression screening. Methods We analyzed 5792 sets of daily mental-health ratings collected from 78 breast cancer patients over a 48-week period. Using the Patient Health Questionnaire-9 (PHQ-9) as the measure of true depression status, we conducted a random-effect logistic panel regression and receiver operating characteristic (ROC) analysis to evaluate the screening performance of the mobile mental-health tracker. In addition, we classified patients into two subgroups based on their adherence level (higher adherence and lower adherence) using a k-means clustering algorithm and compared the screening accuracy between the two groups. Results With the ratio approach, the area under the ROC curve (AUC) is 0.8012, indicating that the performance of depression screening using daily mental-health ratings gathered via mobile mental-health trackers is comparable to the results of PHQ-9 tests. Also, the AUC is significantly higher (P=.002) for the higher adherence group (AUC=0.8524) than for the lower adherence group (AUC=0.7234). This result shows that adherence to self-reporting is associated with a higher accuracy of depression screening. Conclusions Our results

  8. Volcanic eruptions observed with infrasound

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.

    2004-07-01

    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  9. Mothers' Depressive State "Distorts" the Ratings of Depression They Give for Their Sons with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Bitsika, Vicki; Sharpley, Christopher F.

    2016-01-01

    Depression is highly prevalent in children who have an Autism Spectrum Disorder (ASD), potentially confounding accurate diagnosis and treatment planning. Although information about the depressive status of a child is often collected from parents, there is evidence of distortion in parental assessments of their offspring's depression. This…

  10. An examination of the sensitivity of the six-item Hamilton Rating Scale for Depression in a sample of patients suffering from major depressive disorder.

    PubMed Central

    Hooper, C L; Bakish, D

    2000-01-01

    OBJECTIVES: To compare the sensitivity of the 6-item Hamilton Rating Scale for Depression (HRSD6) with the more widely used 17-item Hamilton Rating Scale for Depression (HRSD17) in patients suffering from major depressive disorder, with or without melancholia and/or dysthymic disorder. A secondary objective was to compare the sensitivity of the HRSD6 to the Montgomery-Asberg Depression Rating Scale (MADRS). DESIGN: Retrospective analysis of 4 clinical trials that tested antidepressant therapies. SETTING: Outpatient treatment in a major psychiatric hospital. PARTICIPANTS: One hundred and forty-three male and female outpatients meeting the criteria of the DSM-III-R or DSM-IV for major depressive disorder. OUTCOME MEASURES: HRSD17, HRSD6 and MADRS. RESULTS: The HRSD6 correlated strongly with the HRSD17, both at baseline and termination of treatment, and for the subgroups of double depression and melancholia. The HRSD6 was also correlated significantly with the MADRS at both measurement times, and for the subgroups. Paired t-tests with the HRSD6, HRSD17 and MADRS demonstrated equal sensitivity to change over the course of treatment, both in the full sample and in the dysthymic and melancholic subgroups. CONCLUSIONS: The HRSD6 appears to be as sensitive to change over treatment as the HRSD17 and the MADRS. A shorter, less time-consuming measure of depression may have utility in clinical practice and research. PMID:10740991

  11. Race, life course socioeconomic position, racial discrimination, depressive symptoms and self-rated health.

    PubMed

    Hudson, Darrell L; Puterman, Eli; Bibbins-Domingo, Kirsten; Matthews, Karen A; Adler, Nancy E

    2013-11-01

    Greater levels of socioeconomic position (SEP) are generally associated with better health. However results from previous studies vary across race/ethnicity and health outcomes. Further, the majority of previous studies do not account for the effects of life course SEP on health nor the effects of racial discrimination, which could moderate the effects of SEP on health. Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we examined the relationship between a life course SEP measure on depressive symptoms and self-rated health. A life course SEP was constructed for each participant, using a framework that included parental education and occupation along with respondents' highest level of education and occupation. Interaction terms were created between life course SEP and racial discrimination to determine whether the association between SEP and health was moderated by experiences of racial discrimination. Analyses revealed that higher levels of life course SEP were inversely related to depressive symptoms. Greater life course SEP was positively associated with favorable self-rated health. Racial discrimination was associated with more depressive symptoms and poorer self-rated health. Analyses indicated a significant interaction between life course SEP and racial discrimination on depressive symptoms in the full sample. This suggested that for respondents with greater levels of SEP, racial discrimination was associated with reports of more depressive symptoms. Future research efforts should be made to examine whether individuals' perceptions and experiences of racial discrimination at the interpersonal and structural levels limits their ability to acquire human capital as well as their advancement in education and occupational status.

  12. Silicic Submarine Eruptions: what can erupted pyroclasts tell us?

    NASA Astrophysics Data System (ADS)

    Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.

    2013-12-01

    Our understanding of submarine volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of submarine pumice deposits from modern volcanoes of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of submarine effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.

  13. Psychometric Properties of the Montgomery-Åsberg Depression Rating Scale in Severely Obese Patients.

    PubMed

    Paiva-Medeiros, Paula Francielle; Duarte-Guerra, Leorides Severo; Santo, Marco Aurélio; Lotufo-Neto, Francisco; Wang, Yuan-Pang

    2015-01-01

    Obesity is a chronic condition worldwide and has frequent association with major depression. The Montgomery-Åsberg Depression Rating Scale (MADRS) was applied to obese patients in order to detect briefly and systematically depressive symptoms. The objectives were: to estimate the reliability of the MADRS and to investigate the criterion validity of MADRS. The best cut-off point to detect depressive symptoms was determined in comparison with the Structured Clinical Interview for DSM-IV Axis I Diagnosis (SCID-I). The sample was recruited consecutively from the waiting list of a bariatric surgery service of the university clinic. Trained clinical psychologists applied the assessment instruments. The final sample was comprised of 374 class III obese adults (women 79.9 %, mean age 43.3 years [SD 11.6], mean body mass index 47.0 kg/m2 [SD 7.1]). The mean total score of the MADRS was 7.73 (SD 11.33) for the total sample, with a Cronbach's alpha coefficient of .93. Women presented higher mean score than men (8.08 versus 6.33; p = .23). The best cut-off point was 13/14 in accordance with the Receiver Operating Characteristics (ROC) curve analysis, yielding a sensitivity of .81 and specificity of .85. The overall ability to discriminate depression according to area under the curve was .87. The results showed that the MADRS is a reliable and valid scale to detect depressive symptoms among patients seeking treatment in preoperative period, displaying adequate psychometric properties. PMID:26364907

  14. Depression.

    PubMed

    Tallo, Donato

    2014-04-15

    Reading the CPD article was beneficial to my professional nursing practice and development. I gained a greater understanding of how depression is likely to exacerbate the effects of a physical illness or complicate the treatment of other health conditions. PMID:24712633

  15. Depression and anxiety in ovarian cancer: a systematic review and meta-analysis of prevalence rates

    PubMed Central

    Watts, Sam; Prescott, Philip; Mason, Jessica; McLeod, Natalie; Lewith, George

    2015-01-01

    Objectives To systematically review the literature pertaining to the prevalence of depression and anxiety in patients with ovarian cancer as a function of treatment stage. Design Systematic review and meta-analysis. Participants 3623 patients with ovarian cancer from primary research investigations. Primary outcome measure The prevalence of depression and anxiety in patients with ovarian cancer as a function of treatment stage. Results We identified 24 full journal articles that met the inclusion criteria for entry into the meta-analysis resulting in a pooled sample size of 3623 patients. The meta-analysis of prevalence rates identified pretreatment, on-treatment and post-treatment depression prevalences of 25.34% (CI 22.79% to 28.07%), 22.99% (CI 19.85% to 26.46%) and 12.71% (CI 10.14% to 15.79%), respectively. Pretreatment, on-treatment and post-treatment anxiety prevalences were 19.12% (CI 17.11% to 21.30%), 26.23% (CI 22.30% to 30.56%) and 27.09% (CI 23.10% to 31.49%). Conclusions Our findings suggest that the prevalence of depression and anxiety in women with ovarian cancer, across the treatment spectrum, is significantly greater than in the healthy female population. With the growing emphasis on improving the management of survivorship and quality of life, we conclude that further research is warranted to ensure psychological distress in ovarian cancer is not underdiagnosed and undertreated. PMID:26621509

  16. Sex Differences on Depression Self-Rating Scale in Two Populations: Research Report

    NASA Astrophysics Data System (ADS)

    Seyed-Hossein, Salimi; Mohamad-Reza, Tagavi; Parviz, Azad-Fallah; Reza, Karaminia; Tayebi, A.

    The self-report of depressive symptoms of high school adolescents from two populations were compared. The study aims to find out whether or not; 1) there are significant sex differences between two communities and 2) with regard to the same-sex, there are significant differences between two communities. Nine hundred and twenty eight adolescents from London and 2012 adolescents from six cities from Iran were requested to fill in the Depression Self-Rating Scale (DSRS). The results showed that significant differences between two sexes in each population. All girls had higher mean scores on all items on DSRS than boys. With regard to the same-sex, significant differences were found between either female or male populations in two communities. The research showed that female adolescents from Iran were significantly experienced more depressive symptoms than the Londoners. Similar results were repeated for the male groups. In conclusion, female adolescents are vulnerable to life stressors and tend to experience more negative feedback and interpretations than boys. Moreover, social roles and limitations, particularly for Iranian adolescents, may influence female adolescents to demonstrate depression symptoms.

  17. Guideline adherence rates and interprofessional variation in a vignette study of depression

    PubMed Central

    Tiemeier, H; de Vries, W J; van het, Loo M; Kahan, J; Klazinga, N; Grol, R; Rigter, H

    2002-01-01

    Objective: To assess the appropriateness of and variation in intention-to-treat decisions in the management of depression in the Netherlands. Design: Mailed survey with 22 paper cases (vignettes) based on a population study. Setting: A random sample from four professional groups in the Dutch mental healthcare system. Subjects: 264 general practitioners, psychiatrists, psychotherapists, and clinical psychologists. Main outcome measures: Each vignette contained information on a number of patient characteristics taken from three national depression guidelines. The distribution of patient characteristics was based on data from a population study. Respondents were asked to choose the best treatment option and the best treatment setting. For each vignette we examined which of the selected treatments was appropriate according to the recommendations of the three published Dutch clinical guidelines and a panel of experts. Results: 31% of all intention-to-treat decisions were not consistent with the guidelines. Overall, less severe depression, alcohol abuse, psychotic features, and lack of social resources were related to more inappropriate judgements. There was considerable variation between the professional groups: psychiatrists made more appropriate choices than the other professions although they had the highest rate of overtreatment. Conclusions: There is sufficient variation in the intentions to treat depression to give it priority in quality assessment and guideline development. Efforts to achieve appropriate care should focus on treatment indications, referral patterns, and overtreatment. PMID:12486983

  18. The Association between Neuroticism and Heart Rate Variability Is Not Fully Explained by Cardiovascular Disease and Depression

    PubMed Central

    Čukić, Iva; Bates, Timothy C.

    2015-01-01

    Neuroticism is associated with cardiovascular disease, autonomic reactivity, and depression. Here we address the extent to which neuroticism accounts for the excess heart disease risk associated with depression and test whether cardiac autonomic tone plays a role as mediator. Subjects were derived from a nationally representative sample (n = 1,255: mean age 54.5, SD = 11.5). Higher neuroticism was associated with reduced heart rate variability equally under rest and stress. The baseline structural equation model revealed significant paths from neuroticism to heart rate variability, cardiovascular disease and depression, and between depression and cardiovascular disease, controlling for age, sex, height, weight, and BMI. Dropping both the neuroticism to heart rate variability, and neuroticism to heart disease paths significantly reduced the model fit (p < .001 in each case). We conclude that neuroticism has independent associations with both autonomic reactivity and cardiovascular disease, over and above its associations with depression and other related variables. PMID:25951236

  19. Effects of Anxiety and Depression on Anagram Performance, Ratings of Cognitive Interference, and the Negative Subjective Evaluation of Performance.

    ERIC Educational Resources Information Center

    Zarantonello, Matthew; And Others

    1984-01-01

    Studied the effects of anxiety and depression on anagram performance displayed by college students (N=72). Results showed that depressed-anxious and anxious subjects tended toward reduced efficiency in anagram solution, rated themselves as having experienced signficantly more cognitive interference, and displayed a significantly more negative…

  20. Factor analysis of the Zung self-rating depression scale in a large sample of patients with major depressive disorder in primary care

    PubMed Central

    Romera, Irene; Delgado-Cohen, Helena; Perez, Teresa; Caballero, Luis; Gilaberte, Immaculada

    2008-01-01

    Background The aim of this study was to examine the symptomatic dimensions of depression in a large sample of patients with major depressive disorder (MDD) in the primary care (PC) setting by means of a factor analysis of the Zung self-rating depression scale (ZSDS). Methods A factor analysis was performed, based on the polychoric correlations matrix, between ZSDS items using promax oblique rotation in 1049 PC patients with a diagnosis of MDD (DSM-IV). Results A clinical interpretable four-factor solution consisting of a core depressive factor (I); a cognitive factor (II); an anxiety factor (III) and a somatic factor (IV) was extracted. These factors accounted for 36.9% of the variance on the ZSDS. The 4-factor structure was validated and high coefficients of congruence were obtained (0.98, 0.95, 0.92 and 0.87 for factors I, II, III and IV, respectively). The model seemed to fit the data well with fit indexes within recommended ranges (GFI = 0.9330, AGFI = 0.9112 and RMR = 0.0843). Conclusion Our findings suggest that depressive symptoms in patients with MDD in the PC setting cluster into four dimensions: core depressive, cognitive, anxiety and somatic, by means of a factor analysis of the ZSDS. Further research is needed to identify possible diagnostic, therapeutic or prognostic implications of the different depressive symptomatic profiles. PMID:18194524

  1. Short-term heart rate variability in older patients with newly diagnosed depression.

    PubMed

    Ha, Jee Hyun; Park, Soyeon; Yoon, Daehyun; Kim, Byungsu

    2015-04-30

    Dysfunction of the autonomic nervous system has been considered to be a risk factor for major depressive disorder (MDD) and cardiovascular disease (CVD). The aim of this study was to evaluate short-term heart rate variability (HRV) in elderly patients with newly diagnosed MDD. Thirty MDD patients over 60 years old newly diagnosed by a structured interview were enrolled, free from antidepressants. Socio-demographic data, blood tests, and heart rate variability (HRV) obtained from 5-min ECG were gathered. The MDD group showed significantly lower very low frequency power, low frequency power, high frequency power, and total power in frequency domain. In time domain analysis, the MDD group showed a significantly smaller standard deviation of the NN, root mean square of the differences of the successive NN, and NN50/total number of all NNs. These findings demonstrated a lower HRV in older patients who were newly diagnosed with depression without a history of CVD and antidepressants effect, compared with the control subjects. Low HRV may be an important predictor of both MDD and CVD in elderly. The use of HRV in elderly depressive patients could be a meaningful screening method for risk of CVD. PMID:25747680

  2. Prevalence Rates and Demographic Characteristics Associated with Depression in Pregnancy and the Postpartum.

    ERIC Educational Resources Information Center

    Gotlib, Ian H.; And Others

    1989-01-01

    Examined prevalence of depression in 360 women during pregnancy and after delivery. At both assessments, approximately 25 percent reported elevated levels of depressive symptomatology. Ten percent met diagnostic criteria for depression during pregnancy; 6.8 percent were depressed postpartum. One-half of postpartum depression cases were new onset.…

  3. Effects of Self-Rated Health and Self-Rated Economic Situation on Depressed Mood Via Life Satisfaction Among Older Adults in Costa Rica

    PubMed Central

    Reyes Fernández, Benjamín; Rosero-Bixby, Luis; Koivumaa-Honkanen, Heli

    2016-01-01

    Objective: The study examined the relationship of self-rated health and self-rated economic situation with depressed mood, and life satisfaction as mediator of this relationship among older adults in Costa Rica. Method: A longitudinal study was conducted with a subsample (N = 1,618) from the Costa Rican Longevity and Healthy Aging Study (CRELES). Self-rated health, self-rated economic situation, depressed mood, and life satisfaction were measured at baseline, and depressed mood was reassessed 18 months later. Putative mechanisms for changes in depressed mood were examined by means of conditional process analysis. Results: Self-rated health was negatively associated to depressed mood. This effect took place via life satisfaction. An interaction showed that better economic situation compensated the effect of a low self-rated health on life satisfaction. Discussion: This study suggests that subjective variables such as self-rated health, economic situation, and life satisfaction should be considered when addressing the onset of depressed mood. PMID:26092651

  4. Rates and processes of channel development and recovery following the 1980 eruption of Mount St. Helens, Washington

    USGS Publications Warehouse

    Meyer, D.F.; Martinson, H.A.

    1989-01-01

    Stream channel development in response to the eruption of Mount St. Helens on 18 May 1980, resulted in some of the largest sediment yields documented anywhere on earth. Development of new channels on the 2.7 km3 debris-avalanche deposit in the North Fork Toutle River caused net erosion of as much as 1.3 X 105 t km-2 annually. The principal effect of the blast on channels throughout the 550 km2 devastated area was the subsequent rapid delivery of sand- and silt-size sediment eroded from hillslopes. Since 1984, instability and sedimentation in lahar and blast-affected channels have been within the range of pre-1980 levels. -from Authors

  5. Reaction Rate Acceleration and Tg Depression of Polycyanurate Under Nanopore Confinement

    NASA Astrophysics Data System (ADS)

    Lopez, Evelyn; Simon, Sindee L.

    2015-03-01

    Material properties such as Tg and the reaction kinetics are known to deviate from the bulk when subjected to nano-sized confinement. Previous work from our laboratory on the trimerization of cyanate esters found that the reaction kinetics were faster for a monofunctional reactant compared to a difunctional monomer, whereas the Tg depression was greater for the crosslinked product of the latter compared to the low molecular weight trimer of the former. The origin of the changes in nanoconfined reaction rates differs from those that govern changes in the Tg. The research objective is to further explore the effect that confinement has on reaction kinetics and Tg using a mixture consisting of mono- and di- cyanate ester monomers. The product is an uncrosslinked polycyanurate with Mn = 5240 g/mol and PDI = 1.78. The confinement mediums are controlled pore glasses with diameters ranging from 8.1 to 111.1 nm. The nanopore-confined material was synthesized in-situ and the reaction kinetics are followed by DSC; after the reaction, the Tg values of the nanoconfined polymer where also measured by DSC. An acceleration factor of 13 and a Tg depression of 38 °C are observed for the material confined in the smallest 8.1 nm-diameter pores. The Tg depression is between those of the trimer and network previously studied, while the acceleration of the reaction rate is lower. Our results are consistent with the reaction acceleration arising from packing effects at the pore wall and the Tg depression arising from intrinsic size effects.

  6. Popocatepetl Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Popocatepetl Volcano, almost 30 miles south of Mexico City, erupted yesterday (December 18, 2000) in what authorities are calling its most spectacular eruption since 800 A.D. This morning, Popocatepetl (pronounced poh-poh-kah-TEH-peh-til) continued spewing red-hot rocks as well as a column of smoke and ash about 2.5 miles high into the atmosphere. This true-color image of the volcano was acquired today by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) flying aboard the OrbView-2 satellite. In this image, Popocatepetl's plume (greyish pixels) can be seen blowing southward, away from Mexico City. There is a large cloud bank (bright white pixels) just to the east of the volcanic plume. Although Popocatepetl has been active since 1994-when it awoke from a 70-year slumber-this most recent eruption is most concerning to the greater Mexico City region's 20 million residents. The volcano demonstrated what it can do in 800 A.D. when it belched forth enough lava to fill many of the valleys in the surrounding region. Earlier, scientists warned the citizens of Mexico that there is a dome of lava at the base of the volcano that is causing pressure to build inside. They are concerned that, if it continues to build unabated, this pressure could cause even larger eruptions in the future. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  7. Depression of belowground respiration rates at simulated high moose population densities in boreal forests.

    PubMed

    Persson, Inga-Lill; Nilsson, Mats B; Pastor, John; Eriksson, Tobias; Bergström, Roger; Danell, Kjell

    2009-10-01

    Large herbivores can affect the carbon cycle in boreal forests by changing productivity and plant species composition, which in turn could ultimately alter litter production, nutrient cycling, and the partitioning between aboveground and belowground allocation of carbon. Here we experimentally tested how moose (Alces alces) at different simulated population densities affected belowground respiration rates (estimated as CO2 flux) in young boreal forest stands situated along a site productivity gradient. At high simulated population density, moose browsing considerably depressed belowground respiration rates (24-56% below that of no-moose controls) except during June, where the difference only was 10%. Moose browsing depressed belowground respiration the most on low-productivity sites. Soil moisture and temperature did not affect respiration rates. Impact of moose on belowground respiration was closely linked to litter production and followed Michaelis-Menten dynamics. The main mechanism by which moose decrease belowground respiration rates is likely their effect on photosynthetic biomass (especially decreased productivity of deciduous trees) and total litter production. An increased productivity of deciduous trees along the site productivity gradient causes an unequal effect of moose along the same gradient. The rapid growth of deciduous trees may offer higher resilience against negative effects of moose browsing on litter production and photosynthate allocation to roots.

  8. Sensitivity to changes during antidepressant treatment: a comparison of unidimensional subscales of the Inventory of Depressive Symptomatology (IDS-C) and the Hamilton Depression Rating Scale (HAMD) in patients with mild major, minor or subsyndromal depression.

    PubMed

    Helmreich, Isabella; Wagner, Stefanie; Mergl, Roland; Allgaier, Antje-Kathrin; Hautzinger, Martin; Henkel, Verena; Hegerl, Ulrich; Tadić, André

    2012-06-01

    In the efficacy evaluation of antidepressant treatments, the total score of the Hamilton Depression Rating Scale (HAMD) is still regarded as the 'gold standard'. We previously had shown that the Inventory of Depressive Symptomatology (IDS) was more sensitive to detect depressive symptom changes than the HAMD17 (Helmreich et al. 2011). Furthermore, studies suggest that the unidimensional subscales of the HAMD, which capture the core depressive symptoms, outperform the full HAMD regarding the detection of antidepressant treatment effects. The aim of the present study was to compare several unidimensional subscales of the HAMD and the IDS regarding their sensitivity to changes in depression symptoms in a sample of patients with mild major, minor or subsyndromal depression (MIND). Biweekly IDS-C28 and HAMD17 data from 287 patients of a 10-week randomised, placebo-controlled trial comparing the effectiveness of sertraline and cognitive-behavioural group therapy in patients with MIND were converted to subscale scores and analysed during the antidepressant treatment course. We investigated sensitivity to depressive change for all scales from assessment-to-assessment, in relation to depression severity level and placebo-verum differences. The subscales performed similarly during the treatment course, with slight advantages for some subscales in detecting treatment effects depending on the treatment modality and on the items included. Most changes in depressive symptomatology were detected by the IDS short scale, but regarding the effect sizes, it performed worse than most subscales. Unidimensional subscales are a time- and cost-saving option in judging drug therapy outcomes, especially in antidepressant treatment efficacy studies. However, subscales do not cover all facets of depression (e.g. atypical symptoms, sleep disturbances), which might be important for comprehensively understanding the nature of the disease depression. Therefore, the cost-to-benefit ratio must be

  9. Sensitivity to changes during antidepressant treatment: a comparison of unidimensional subscales of the Inventory of Depressive Symptomatology (IDS-C) and the Hamilton Depression Rating Scale (HAMD) in patients with mild major, minor or subsyndromal depression.

    PubMed

    Helmreich, Isabella; Wagner, Stefanie; Mergl, Roland; Allgaier, Antje-Kathrin; Hautzinger, Martin; Henkel, Verena; Hegerl, Ulrich; Tadić, André

    2012-06-01

    In the efficacy evaluation of antidepressant treatments, the total score of the Hamilton Depression Rating Scale (HAMD) is still regarded as the 'gold standard'. We previously had shown that the Inventory of Depressive Symptomatology (IDS) was more sensitive to detect depressive symptom changes than the HAMD17 (Helmreich et al. 2011). Furthermore, studies suggest that the unidimensional subscales of the HAMD, which capture the core depressive symptoms, outperform the full HAMD regarding the detection of antidepressant treatment effects. The aim of the present study was to compare several unidimensional subscales of the HAMD and the IDS regarding their sensitivity to changes in depression symptoms in a sample of patients with mild major, minor or subsyndromal depression (MIND). Biweekly IDS-C28 and HAMD17 data from 287 patients of a 10-week randomised, placebo-controlled trial comparing the effectiveness of sertraline and cognitive-behavioural group therapy in patients with MIND were converted to subscale scores and analysed during the antidepressant treatment course. We investigated sensitivity to depressive change for all scales from assessment-to-assessment, in relation to depression severity level and placebo-verum differences. The subscales performed similarly during the treatment course, with slight advantages for some subscales in detecting treatment effects depending on the treatment modality and on the items included. Most changes in depressive symptomatology were detected by the IDS short scale, but regarding the effect sizes, it performed worse than most subscales. Unidimensional subscales are a time- and cost-saving option in judging drug therapy outcomes, especially in antidepressant treatment efficacy studies. However, subscales do not cover all facets of depression (e.g. atypical symptoms, sleep disturbances), which might be important for comprehensively understanding the nature of the disease depression. Therefore, the cost-to-benefit ratio must be

  10. Depression Anxiety Stress Scales-21: measurement and structural invariance across ratings of men and women.

    PubMed

    Gomez, Rapson; Summers, Mathew; Summers, Avril; Wolf, Anna; Summers, Jeff

    2014-08-01

    The current study examined the measurement and structural invariance of the Depression Anxiety Stress Scales-21 (DASS-21) across ratings provided by men (N = 227) and women (N = 460). Multiple-group confirmatory factor analysis (CFA) supported full metric invariance and intercepts invariance for 20 of the 21 items. Invariance for all item intercepts was supported by multiple indicators multiple causes (MIMIC) procedure that controlled for the effects of age. Multiple-group CFA supported invariance for all factor variances and covariances. This procedure and the MIMIC analyses found equivalency for all latent mean scores. These findings indicate good support for measurement and structural invariance of the DASS-21 rating across men and women. The psychometric and practical implications of the findings are discussed.

  11. Self-Rated Mental Health: Screening for Depression and Posttraumatic Stress Disorder Among Women Exposed to Perinatal Intimate Partner Violence.

    PubMed

    Kastello, Jennifer C; Jacobsen, Kathryn H; Gaffney, Kathleen F; Kodadek, Marie P; Bullock, Linda C; Sharps, Phyllis W

    2015-11-01

    The purpose of the current study was to evaluate the validity of a single-item, self-rated mental health (SRMH) measure in the identification of women at risk for depression and posttraumatic stress disorder (PTSD). Baseline data of 239 low-income women participating in an intimate partner violence (IPV) intervention study were analyzed. PTSD was measured with the Davidson Trauma Scale. Risk for depression was determined using the Edinburgh Postnatal Depression Scale. SRMH was assessed with a single item asking participants to rate their mental health at the time of the baseline interview. Single-item measures can be an efficient way to increase the proportion of patients screened for mental health disorders. Although SRMH is not a strong indicator of PTSD, it may be useful in identifying pregnant women who are at increased risk for depression and need further comprehensive assessment in the clinical setting. Future research examining the use of SRMH among high-risk populations is needed.

  12. Estimation of lava flow field volumes and volumetric effusion rates from airborne radar profiling and other data: Monitoring of the Nornahraun (Holuhraun) 2014/15 eruption in Iceland

    NASA Astrophysics Data System (ADS)

    Dürig, Tobias; Gudmundsson, Magnús; Högnadóttir, Thordís; Jónsdóttir, Ingibjörg; Gudbjörnsson, Snaebjörn; Lárusson, Örnólfur; Höskuldsson, Ármann; Thordarson, Thorvaldur; Riishuus, Morten; Magnússon, Eyjólfur

    2015-04-01

    Monitoring of lava-producing eruptions involves systematic measurement of flow field volumes, which in turn can be used to obtain average magma discharge over the period of observation. However, given inaccessibility to the interior parts of active lava fields, remote sensing techniques must be applied. Several satellite platforms provide data that can be geo-referenced, allowing area estimation. However, unless sterographic or tandem satellite data are available, the determination of thicknesses is non-trivial. The ongoing eruption ('Nornaeldar')at Dyngjusandurin the Icelandic highlands offers an opportunity to monitor the temporal and spatial evolution of a typical Icelandic lava flow field. The mode of emplacementis complex and includesboth horizontal and vertical stacking, inflation of lobes and topographic inversions. Due to the large extent of the flow field (>83 km2 on 5 Jan 2015, and still growing) and its considerable local variation in thickness (30 m) and surface roughness, obtaining robust quantification of lava thicknesses is very challenging,despite the lava is being emplaced onto a low-relief sandur plain. Creative methods have been implemented to obtain as reliable observation as possible into the third dimension: Next to areal extent measurements from satellites and maps generated with airborne synthetic-aperture radar (SAR), lava thickness profiles are regularly obtained by low-level flights with a fixed-wing aircraft that is equipped with a ground clearance radar coupled witha submeter DGPS,a system originally designed for monitoring surface changes of glaciers above geothermally active areas.The resulting radar profile data are supplemented by analyses of aerial photos and complemented by results from an array of ground based thickness measurement methods. The initial results indicate that average effusion ratewas ~200 m3/s in the first weeks of the eruption (end August, early September) but declined to 50-100 m3/s in November to December period

  13. The X-linked inhibitor of apoptosis regulates long-term depression and learning rate.

    PubMed

    Gibon, Julien; Unsain, Nicolas; Gamache, Karine; Thomas, Rhalena A; De Leon, Andres; Johnstone, Aaron; Nader, Karim; Séguéla, Philippe; Barker, Philip A

    2016-09-01

    Hippocampal long-term depression (LTD) is an active form of synaptic plasticity that is necessary for consolidation of spatial memory, contextual fear memory, and novelty acquisition. Recent studies have shown that caspases (CASPs) play an important role in NMDA receptor-dependent LTD and are involved in postsynaptic remodeling and synaptic maturation. In the present study, we examined the role of X-linked inhibitor of apoptosis (XIAP), a putative endogenous CASP inhibitor, in synaptic plasticity in the hippocampus. Analysis in acute brain slices and in cultured hippocampal neurons revealed that XIAP deletion increases CASP-3 activity, enhances α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor internalization, sharply increases LTD, and significantly reduces synapse density. In vivo behaviors related to memory were also altered in XIAP(-/-) mice, with faster acquisition of spatial object location and increased fear memory observed. Together, these results indicate that XIAP plays an important physiologic role in regulating sublethal CASP-3 activity within central neurons and thereby facilitates synaptic plasticity and memory acquisition.-Gibon, J., Unsain, N., Gamache, K., Thomas, R. A., De Leon, A., Johnstone, A., Nader, K., Séguéla, P., Barker, P. A. The X-linked inhibitor of apoptosis regulates long-term depression and learning rate.

  14. Heart rate variability during motor and cognitive tasks in females with major depressive disorder

    PubMed Central

    Nugent, Allison Carol; Bain, Earle Eugene; Thayer, Julian Francis; Sollers, John James; Drevets, Wayne Curtis

    2010-01-01

    Research indicates that major depressive disorder (MDD) is associated with alterations in autonomic control, particularly cardiac control as measured by heart rate variability (HRV). In this preliminary study, we investigated the neural correlates of autonomic control by measuring both HRV and associated brain activity during the performance of mildly stressful tasks. Medically healthy female subjects with MDD (N=10) and healthy controls (N=7) underwent H2 15O-PET and ECG recording while performing a handgrip motor task and an n-back task. Indices of HRV were calculated and correlated with regional cerebral blood flow (rCBF). Differences in the rCBF and HRV correlations between depressed and healthy subjects were evident in both the medial and lateral orbital cortices. In addition, these areas appeared to be involved in different facets of autonomic control with regard to sympathetic or parasympathetic dominance of cardiac control. These results are consistent with the known roles of networks within the orbital cortex in both autonomic control and the pathophysiology of MDD. PMID:21129936

  15. Continuous overnight observation of human premolar eruption.

    PubMed

    Risinger, R K; Proffit, W R

    1996-01-01

    Such observation was made possible by transmitting the image of a mobile ceramic ruling on the erupting maxillary second premolar to a video-microscope via a coaxial fibreoptic cable. The cable was inserted into a reference bar secured to the adjacent first molar and first premolar. The image of the ruling was superimposed with the image from a surveillance camera focused on the patient and continuously recorded on video-tape along with the participant's blood pressure, pulse rate, electromyographic activity and occlusal contact sounds. Overnight data from 12 individuals clearly revealed a circadian rhythm in eruption during the prefunctional spurt. On average, the maxillary second premolar erupted 41 microns during an 11-h overnight observation, with almost all the eruption occurring in the late evening from 8 p.m. to 1 a.m. After 1 a.m., eruption typically ceased, with a tendency for intrusion to occur until 7 a.m. Sleep increased the rate of eruption during the late evening, but did not influence the eruption rate during the early morning. Haemodynamic changes, including blood pressure and pulse rate, did not have a significant impact on the rhythm of eruption. The observed eruption rhythm is most probably caused by changing hormone levels and their effect on the periodontal ligament. The late-evening eruption of human premolars coincides with the late-evening secretion of growth hormone and thyroid hormone typically found in humans. PMID:9022915

  16. No Significant Difference in Depression Rate in Employed and Unemployed in a Pair-Matched Study Design

    PubMed Central

    Mihai, Adriana; Ricean, Alina; Voidazan, Septimiu

    2014-01-01

    Objectives: The main objective of this study was to evaluate the differences of depression rate in employed and unemployed persons in the period of financial and economic crisis in Romania, in a pair-matched study design. Method: The cross-sectional study uses a pair match design (395 pairs) of two groups of employed and unemployed persons. Other socio-demographic risk factors of depression (gender, age, marital status, residence, ethnicity, educational level, and profession) were controlled. The study was done in a historical period of economic crisis, 2009–2010. For the screening of depression we used the patient health questionnaire-9. Results: There were no statistical differences (p = 0.054) between the depression rates in the employed (17.98%) and unemployed (23.80%) samples. The depression rate in both groups was higher in females, age (51–55), marital status (divorced), living in the rural area, with a low level of education and poverty. Suicidal ideas are more frequent in men, employed persons with low level of education and in unemployed persons with medium level of education. Conclusion: The exposure to short term unemployment status was not associated with change in depression rate in the period of financial and economic crisis in Romania, comparing with controls pair-matched. Unemployment status increases the depression rate only in vulnerable groups such as single or divorced women; and suicidal ideas were associated with the unemployment status (longer than 8 months) in men from rural area with medium level of education. PMID:25105113

  17. Determination of growth rate depression of some green algae by atrazine

    SciTech Connect

    Hersh, C.M.; Crumpton, W.G.

    1987-12-01

    A common contaminant of surface waters of agricultural regions is the triazine herbicide, atrazine (2-chloro-4-ethylamino-6-isoproplyamino-s-triazine). Atrazine effectively inhibits growth and photosynthesis of most plants, including freshwater algae. Both depression of growth rate and reduced yield have been used as parameters in studies of the effects of atrazine on algal growth. Considerable variation exists among algal toxicity methods despite attempts at standardization. Experimental endpoints range from percent inhibitions to EC50s. Algae from two different Iowa springs were the subjects of a study of naturally occurring atrazine tolerance. The authors report here the results of two aspects of that study: development of a quick method of assessing toxin effects on algal growth, and investigation of a ecologically meaningful endpoint for toxin-growth experiments.

  18. The daily rhythm of tooth eruption.

    PubMed

    Lee, C F; Proffit, W R

    1995-01-01

    A video microscope system, which can resolve tooth movements to 1 to 2 microns, was used to monitor the eruption of 17 human maxillary second premolars in the prefunctional phase. Eruptive movement was detected by the change in position of an optical ruling on the erupting tooth relative to a reference ruling on the occluding adjacent teeth. Eruption was observed as the teeth erupted toward the occlusal plane over approximately a 41-hour period, from late Friday afternoon until Sunday noon. Half hourly observations were made during a 6 to 8-hour continuous laboratory session, which was during the day (9 AM to 5 PM) for nine of the subjects, and during the evening (5 to 11 PM) for eight. A similar pattern of eruption was seen for all subjects. The tooth intruded from before to after dinner on the first day, erupted significantly overnight, ceased eruption and approximately maintained its position during the next day, and erupted again during the second night. On the average, a slight intrusion was observed during the day, and statistically significant intrusion was associated with breakfast and dinner. Eruption occurred during the evening observation period, and the rate of evening eruption was significantly greater in children who were supine and relaxed than those who were upright and active. The 24-hour eruption rate was slower for teeth that were within 1.5 mm of the occlusal plane. The circadian eruption rhythm may be related to fluctuations of hormonal levels that affect metabolic activities within the periodontal ligament. It is also possible that a transient reduction in pressures by the cheeks, lips, and tongue during periods of rest allows eruption to occur then.

  19. Heart rate depression during sleep apnea depends on hypoxic chemosensitivity. A study at high altitude.

    PubMed

    Masuyama, S; Shinozaki, T; Kohchiyama, S; Okita, S; Kimura, H; Honda, Y; Kuriyama, T

    1990-01-01

    To clarify the heart rate (HR) slowing response during periodic breathing (PB) with apnea and its relationship to hypoxic ventilatory response (HVR), sleep studies were done in seven Japanese climbers at 5,360 m in the Kunlun mountains of China in 1986. Apnea duration (APD), arterial oxygen saturation changes (delta SaO2), and the percentage of heart rate changes (delta HR%) during PB with apnea were analyzed. The data were compared with hypoxic heart rate and ventilatory responses assessed at sea level. HR during the apneic period (APD, 10, 8 +/- 1.2 s; delta SaO2, 10.2 +/- 1.8%) was significantly smaller than that during the ventilatory period of PB (56.0 +/- 5.1/min and 74.6 +/- 6.2/min, respectively). This HR slowing or acceleration alternated in accordance with off and on activities in ventilation. The magnitude of delta HR% had a significant correlation with that of delta SaO2 (p less than 0.01). The sensitivity of HR depression to desaturation (delta HR%/delta SaO2) was smaller in low HVR climbers than in high HVR climbers. We concluded that these results can be ascribed to the fact that the primary effect of peripheral chemoreceptors on the cardiovascular center is vagotonia, and the effect is overridden by the vagal pulmonary inflation reflex.

  20. The Validity of the Different Versions of the Hamilton Depression Scale in Separating Remission Rates of Placebo and Antidepressants in Clinical Trials of Major Depression.

    PubMed

    Kyle, Phillip Raphael; Lemming, Ole Michael; Timmerby, Nina; Søndergaard, Susan; Andreasson, Kate; Bech, Per

    2016-10-01

    Our objective was to validate the different versions of the Hamilton Depression Scale (HAM-D) both psychometrically (scalability) and clinically in discriminating antidepressants from placebo in terms of remission rates in an 8-week clinical trial in the acute treatment of major depression. The traditional HAM-D17 version was compared with the shorter HAM-D6 and the longer HAM-D21 or HAM-D24 in a fixed-dose placebo-controlled vortioxetine study. Clinical Global Impression of Severity scores were used to establish standardized cutoff scores for remission across each scale. Using these cutoff scores, we compared the ability of each scale to separate drug-placebo remission rates, evaluated by the number needed to treat for clinical evidence. The HAM-D6 was superior to HAM-D17 in separating drug-placebo remission rates at the end point, defined as number needed to treat of less than 10. More items in the longer HAM-D versions indicated smaller discriminating validity over placebo. The HAM-D6 indicated a dose effect on remission for vortioxetine in both moderate and severe major depression. The brief HAM-D6 was thus found superior to HAM-D17, HAM-D21, and HAM-D24 both in terms of scalability and in discriminating antidepressants from placebo.

  1. The Validity of the Different Versions of the Hamilton Depression Scale in Separating Remission Rates of Placebo and Antidepressants in Clinical Trials of Major Depression.

    PubMed

    Kyle, Phillip Raphael; Lemming, Ole Michael; Timmerby, Nina; Søndergaard, Susan; Andreasson, Kate; Bech, Per

    2016-10-01

    Our objective was to validate the different versions of the Hamilton Depression Scale (HAM-D) both psychometrically (scalability) and clinically in discriminating antidepressants from placebo in terms of remission rates in an 8-week clinical trial in the acute treatment of major depression. The traditional HAM-D17 version was compared with the shorter HAM-D6 and the longer HAM-D21 or HAM-D24 in a fixed-dose placebo-controlled vortioxetine study. Clinical Global Impression of Severity scores were used to establish standardized cutoff scores for remission across each scale. Using these cutoff scores, we compared the ability of each scale to separate drug-placebo remission rates, evaluated by the number needed to treat for clinical evidence. The HAM-D6 was superior to HAM-D17 in separating drug-placebo remission rates at the end point, defined as number needed to treat of less than 10. More items in the longer HAM-D versions indicated smaller discriminating validity over placebo. The HAM-D6 indicated a dose effect on remission for vortioxetine in both moderate and severe major depression. The brief HAM-D6 was thus found superior to HAM-D17, HAM-D21, and HAM-D24 both in terms of scalability and in discriminating antidepressants from placebo. PMID:27525966

  2. Comparing Dynamics in Eruptive and Non-Eruptive Flares

    NASA Astrophysics Data System (ADS)

    Nitta, Nariaki; Tarbell, Theodore D.; Slater, Gregory L.; Frank, Zoe Anne

    2016-05-01

    Close comparison of EUV and coronagraph data suggests that there may not be clear distinction between eruptive and non-eruptive flares as far as the coronal and chromospheric signatures are concerned. Here we define eruptive and non-eruptive flares in terms of the presence and absence of the associated coronal mass ejection (CME). We have studied several flares in both categories using Hinode/SOT and IRIS data. The pointing of the Hinode/SOT data has been updated by correlating them with AIA 1700 A images. We show our initial results about how the flare development compares in eruptive and non-eruptive flares, including the reconnection rate as derived from the magnetic field swept over by flare ribbons (in SOT Ca images), and the line-of-sight velocities at different locations and temperatures (in IRIS spectral data). We also discuss large-scale disturbances and related CMEs in SDO/AIA and SOHO/LASCO data as context information.

  3. An ergodic approach to eruption hazard scaling

    NASA Astrophysics Data System (ADS)

    De la Cruz-Reyna, Servando; Mendoza-Rosas, Ana Teresa

    2014-05-01

    The complexity and indeterminacy of volcanic processes demand the use of statistical methods to analyze the expectations of the occurrence and size of future eruptions. The probability of a volcano producing potentially destructive eruptions in a given time interval may be estimated analyzing the sequence of past eruptions assuming a physically plausible process. Since the threat posed by eruptions depends on their mass or energy release (magnitude) and on their emission rate (intensity), the Volcanic Explosivity Index is a suitable measure to quantify the eruptive events, particularly considering that the largest available global catalogues use that measure. The definition of volcanic hazard is thus posed here in terms of the expected annual release of energy by eruptions in each VEI category. This concept is based on the ergodic property of a large set of volcanoes to release about the same amount of energy in each VEI category over a sufficiently large time interval. This property is however constrained to the VEI range of eruptions that constitute complete catalogues (VEI >2) in the lower end, and to the extreme eruptions that may destroy or significantly alter a volcanic system, such as the large caldera-forming eruptions (VEI < 7). In such conditions, a simple power law for eruptions at the global level relating the global rate of energy release to the eruption magnitude has been proposed as a statistical basis for eruptive event model development. Following the above mentioned arguments, we assume that a similar scaling law rules the annual rate at which energy is released by eruptions at individual volcanoes as log(EmRm)=bM+a, where Em is the energy released by eruptions in the VEI magnitude class M, and Rm is the occurrence rate of such eruptions over times ranges in which catalogues may be considered complete. The parameters b and a depend on the eruptive history of individual volcanoes, the former determining the preferred mode of the volcano to release

  4. The Hamilton Rating Scale for Depression: The making of a “gold standard” and the unmaking of a chronic illness, 1960–1980

    PubMed Central

    Worboys, Michael

    2013-01-01

    Objectives: To show why and how the Hamilton Rating Scale for Depression became the ‘Gold Standard’ for assessing therapies from the mid-1960s and how it was used to frame depression as a short-term and curable illness rather than a chronic one. Methods: My approach is that of the social construction of knowledge, identifying the interests, institutional contexts and practices that produce knowledge claims and then mapping the social processes of their circulation, validation and acceptance. Results: The circulation and validation of Hamilton Rating Scale for Depression was relatively slow and it became a ‘Gold Standard’ ‘from below’, from an emerging consensus amongst psychiatrists undertaking clinical trials for depression, which from the 1960s were principally with psychopharmaceuticals for short-term illness. Hamilton Rating Scale for Depression, drug trials and the construction of depression as non-chronic were mutually constituted. Discussion: Hamilton Rating Scale for Depression framed depression and its sufferers in new ways, leading psychiatrists to understand illness as a treatable episode, rather than a life course condition. As such, Hamilton Rating Scale for Depression served the interests of psychiatrists and psychiatry in its new era of drug therapy outside the mental hospital. However, Hamilton Rating Scale for Depression was a strange kind of ‘standard’, being quite non-standard in the widely varying ways it was used and the meanings given to its findings. PMID:23172888

  5. Rates of major depressive disorder and clinical outcomes following traumatic brain injury

    PubMed Central

    Bombardier, Charles H.; Fann, Jesse R.; Temkin, Nancy R.; Esselman, Peter C.; Barber, Jason; Dikmen, Sureyya S.

    2011-01-01

    Context Uncertainties exist about the rates, predictors and outcomes of major depressive disorder (MDD) among people with traumatic brain injury (TBI). Objectives To describe MDD related rates, predictors, outcomes and treatment during the first year after TBI Design Cohort from 6/2001–3/2005 followed by structured telephone interviews at months 1–6, 8, 10, and 12 (data collection ending 2/2006). Setting Harborview Medical Center, a Level I trauma center in Seattle, WA Participants 559 consecutively hospitalized adults with complicated mild to severe TBI Main Outcome Measures The Patient Health Questionnaire (PHQ) depression and anxiety modules were administered at each assessment and the European Quality of Life measure (EQ-5D) was given at 12 months. Results 53% met criteria for MDD at least once in the follow-up period. Point prevalences ranged between 31% at one month and 21% at six months. In a multivariate model, increased risk of MDD after TBI was associated with MDD at the time of injury (risk ratio [RR], 1.62; 95% confidence interval [CI], 1.37–1.91), history of MDD prior to injury (but not at the time of injury) (RR, 1.54; 95% CI, 1.31–1.82), age (RR, 0.61; 95% CI, 0.44–0.83 for 60+ years vs. 18–29 years) and lifetime alcohol dependence (RR, 1.34; 95% CI, 1.14–1.57). Those with MDD were more likely to report co-morbid anxiety disorders after TBI than those without MDD (60% versus 7%; RR, 8.77; 95% CI, 5.56–13.83). Only 44% of those with MDD received antidepressants or counseling. After adjusting for predictors of MDD, persons with MDD reported lower quality of life at one year, compared to the nondepressed group. Conclusions Among a cohort of patients hospitalized for TBI, 53% met criteria for MDD during the first year after TBI. MDD was associated with prior history of MDD and was an independent predictor of poorer health-related quality of life. PMID:20483970

  6. Jupiter Eruptions

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  7. Eruption conditions of spatter deposits

    NASA Astrophysics Data System (ADS)

    Rader, Erika; Geist, Dennis

    2015-10-01

    Spatter is an eruptive product that forms within a narrow range of thermal conditions: it must be hot enough to deform and agglutinate, but not so hot that clasts completely re-fuse and remobilize as clastogenic lava. This narrow thermal window of spatter-forming conditions allows for quantitative prediction of cooling rates and accumulation rates. Cooling and accumulation rates then provide information that enables estimates of eruption parameters for inaccessible and prehistoric deposits. High-temperature experiments conducted on basaltic scoria from Devil's Garden, Oregon have revealed the eruption temperature was ~ 1130 °C. The strength welds formed between experimental clasts is shown to depend on cooling rate. Natural samples are compared to the experimental samples by measuring tensile strength and welded area between clasts. The weld strength in natural deposits yields estimates of cooling rates that range between 2.5 °C and 48 °C/min, with the majority of the samples grouping between 7 °C and 14 °C/min. Thermal models based on these cooling rates yield spatter accumulation rates of 0.5-1.8 m/h in the Devil's Garden spatter deposits. We provide a general model for cooling and accumulation rates for spatter cones, ramparts, and hornitos, which allow estimation of the factors that control basaltic eruptive products.

  8. The Impact of Maternal Depressive Symptomatology on Ratings of Children with ADHD and Child Confederates

    ERIC Educational Resources Information Center

    Baumann, B. L.; Pelham Jr., W. E.; Lang, A. R.; Jacob, R. G.; Blumenthal, J. D.

    2004-01-01

    Some researchers who have studied children with behavior problems have suggested that depressed mothers distort reports of deviance in their children, perhaps contributing to misdiagnoses; however, investigations studying mothers with current or past depression have not clearly indicated such a bias. Because some of this equivocation may be due to…

  9. Patterns of historical eruptions at Hawaiian volcanoes

    USGS Publications Warehouse

    Klein, F.W.

    1982-01-01

    Hawaiian eruptions are largely random phenomena displaying no periodicity; that is, future eruptions are relatively independent of the date of the last eruption. Several simultaneous processes probably govern eruption timing so that it appears random. I have performed statistical tests for nonrandomness on the repose times between eruptions and on the sequence of event types. Statistical differences that have physical consequences exist between large and small eruptions, summit and flank eruptions, and intrusive and extrusive events. Thus, large-volume eruptions tend to be followed by longer reposes as shallow magma reservoirs refill. On Kilauea, both summit eruptions and rapid intrusions tend to cluster at times associated with other physical events on the volcano. The longest recorded reposes of both Kilauea and Mauna Loa apparently are not random phenomena, for they appear to be associated with increased activity at the other volcano. Both eruption rates and volumes are consistent with a constant but alternating magma supply to the two volcanoes and an approximately five-fold larger magma reservoir at Mauna Loa than at Kilauea. ?? 1982.

  10. Validity and test–retest reliability of the Persian version of the Montgomery–Asberg Depression Rating Scale

    PubMed Central

    Ahmadpanah, Mohammad; Sheikhbabaei, Meisam; Haghighi, Mohammad; Roham, Fatemeh; Jahangard, Leila; Akhondi, Amineh; Sadeghi Bahmani, Dena; Bajoghli, Hafez; Holsboer-Trachsler, Edith; Brand, Serge

    2016-01-01

    Background and aims The Montgomery–Asberg Depression Rating Scale (MADRS) is an expert’s rating tool to assess the severity and symptoms of depression. The aim of the present two studies was to validate the Persian version of the MADRS and determine its test–retest reliability in patients diagnosed with major depressive disorders (MDD). Methods In study 1, the translated MADRS and the Hamilton Depression Rating Scale (HDRS) were applied to 210 patients diagnosed with MDD and 100 healthy adults. In study 2, 200 patients diagnosed with MDD were assessed with the MADRS in face-to-face interviews. Thereafter, 100 patients were assessed 3–14 days later, again via face-to-face-interviews, while the other 100 patients were assessed 3–14 days later via a telephone interview. Results Study 1: The MADRS and HDRS scores between patients with MDD and healthy controls differed significantly. Agreement between scoring of the MADRS and HDRS was high (r=0.95). Study 2: The intraclass correlation coefficient (test–retest reliability) was r=0.944 for the face-to-face interviews, and r=0.959 for the telephone interviews. Conclusion The present data suggest that the Persian MADRS has high validity and excellent test–retest reliability over a time interval of 3–14 days, irrespective of whether the second assessment was carried out face-to-face or via a telephone interview. PMID:27022265

  11. Variations in eruption style during the 1931A.D. eruption of Aniakchak volcano, Alaska

    USGS Publications Warehouse

    Nicholson, R.S.; Gardner, J.E.; Neal, C.A.

    2011-01-01

    The 1931A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9km3, which corresponds to approximately 0.3km3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style. ?? 2011 Elsevier B.V..

  12. Variations in eruption style during the 1931 A.D. eruption of Aniakchak volcano, Alaska

    USGS Publications Warehouse

    Nicholson, Robert S.; Gardner, James E.; Neal, Christina A.

    2011-01-01

    The 1931 A.D. eruption of Aniakchak volcano, Alaska, progressed from subplinian to effusive eruptive style and from trachydacite to basaltic andesite composition from multiple vent locations. Eyewitness accounts and new studies of deposit stratigraphy provide a combined narrative of eruptive events. Additional field, compositional, grain size, componentry, density, and grain morphology data document the influences on changing eruptive style as the eruption progressed. The eruption began on 1 May 1931 A.D. when a large subplinian eruption column produced vesicular juvenile-rich tephra. Subsequent activity was more intermittent, as magma interacted with groundwater and phreatomagmatic ash and lithic-rich tephra was dispersed up to 600 km downwind. Final erupted products were more mafic in composition and the eruption became more strombolian in style. Stratigraphic evidence suggests that two trachydacitic lava flows were erupted from separate but adjacent vents before the phreatomagmatic phase concluded and that basaltic andesite lava from a third vent began to effuse near the end of explosive activity. The estimated total bulk volume of the eruption is 0.9 km3, which corresponds to approximately 0.3 km3 of magma. Eruption style changes are interpreted as follows: (1) a decrease in magma supply rate caused the change from subplinian to phreatomagmatic eruption; (2) a subsequent change in magma composition caused the transition from phreatomagmatic to strombolian eruption style. Additionally, the explosion and effusion of a similar magma composition from three separate vents indicates how the pre-existing caldera structure controlled the pathway of shallow magma ascent, thus influencing eruption style.

  13. Rate and Predictors of Persistent Major Depressive Disorder in a Nationally Representative Sample.

    PubMed

    Walker, Elizabeth Reisinger; Druss, Benjamin G

    2015-08-01

    This study examined predictors of persistent major depressive disorder over 10 years, focusing on the effects of clinical variables, physical health, and social support. Data from the National Survey of Midlife Development in the United States in 1995-1996 and 2004-2006 were analyzed. Logistic regression was used to predict non-recovery from major depression among individuals who met clinical-based criteria for major depressive disorder at baseline. Fifteen percent of the total sample was classified as having major depression in 1995-1996; of these individuals, 37 % had major depression in 2004-2006. Baseline variables that were significantly associated with persistent major depression at follow-up were being female, having never married, having two or more chronic medical conditions, experiencing activity limitation, and less contact with family. Therefore, treatment strategies focused on physical health, social support, and mental health needs are necessary to comprehensively address the factors that contribute to persistent major depressive disorder.

  14. Heart rate variability in major depressive disorder and after antidepressant treatment with agomelatine and paroxetine: Findings from the Taiwan Study of Depression and Anxiety (TAISDA).

    PubMed

    Yeh, Ta-Chuan; Kao, Lien-Cheng; Tzeng, Nian-Sheng; Kuo, Terry B J; Huang, San-Yuan; Chang, Chuan-Chia; Chang, Hsin-An

    2016-01-01

    Evidence from previous studies suggests that heart rate variability (HRV) is reduced in major depressive disorder (MDD). However, whether this reduction is attributable to the disorder per se or to medication, since antidepressants may also affect HRV, is still debated. There is a dearth of information regarding the effects of agomelatine, a novel antidepressant, on HRV. Here, we investigated whether HRV is reduced in MDD and compared the effects of agomelatine and paroxetine on HRV. We recruited 618 physically healthy unmedicated patients with MDD and 506 healthy volunteers aged 20-65 years. Frequency-domain measures of resting HRV were obtained at the time of enrollment for all participants. For patients with MDD, these measures were obtained again after 6 weeks of either agomelatine or paroxetine monotherapy. Compared with healthy subjects, unmedicated patients with MDD exhibited significantly lower variance (total HRV), low frequency (LF), and high frequency (HF) HRV, and a higher LF/HF ratio. Depression severity independently contributed to decreased HRV and vagal tone. Fifty-six patients completed the open-label trial (n=29 for agomelatine, n=27 for paroxetine). Between-group analyses showed a significant group-by-time interaction for LF-HRV and HF-HRV, driven by increases in LF-HRV and HF-HRV only after agomelatine treatment. Within the paroxetine-treated group, there were no significant changes in mean R-R intervals or any HRV indices. We therefore concluded that MDD is associated with reduced HRV, which is inversely related to depression severity. Compared with paroxetine, agomelatine has a more vagotonic effect, suggesting greater cardiovascular safety. Clinicians should consider HRV effects while selecting antidepressants especially for depressed patients who already have decreased cardiac vagal tone.

  15. Heart rate variability in major depressive disorder and after antidepressant treatment with agomelatine and paroxetine: Findings from the Taiwan Study of Depression and Anxiety (TAISDA).

    PubMed

    Yeh, Ta-Chuan; Kao, Lien-Cheng; Tzeng, Nian-Sheng; Kuo, Terry B J; Huang, San-Yuan; Chang, Chuan-Chia; Chang, Hsin-An

    2016-01-01

    Evidence from previous studies suggests that heart rate variability (HRV) is reduced in major depressive disorder (MDD). However, whether this reduction is attributable to the disorder per se or to medication, since antidepressants may also affect HRV, is still debated. There is a dearth of information regarding the effects of agomelatine, a novel antidepressant, on HRV. Here, we investigated whether HRV is reduced in MDD and compared the effects of agomelatine and paroxetine on HRV. We recruited 618 physically healthy unmedicated patients with MDD and 506 healthy volunteers aged 20-65 years. Frequency-domain measures of resting HRV were obtained at the time of enrollment for all participants. For patients with MDD, these measures were obtained again after 6 weeks of either agomelatine or paroxetine monotherapy. Compared with healthy subjects, unmedicated patients with MDD exhibited significantly lower variance (total HRV), low frequency (LF), and high frequency (HF) HRV, and a higher LF/HF ratio. Depression severity independently contributed to decreased HRV and vagal tone. Fifty-six patients completed the open-label trial (n=29 for agomelatine, n=27 for paroxetine). Between-group analyses showed a significant group-by-time interaction for LF-HRV and HF-HRV, driven by increases in LF-HRV and HF-HRV only after agomelatine treatment. Within the paroxetine-treated group, there were no significant changes in mean R-R intervals or any HRV indices. We therefore concluded that MDD is associated with reduced HRV, which is inversely related to depression severity. Compared with paroxetine, agomelatine has a more vagotonic effect, suggesting greater cardiovascular safety. Clinicians should consider HRV effects while selecting antidepressants especially for depressed patients who already have decreased cardiac vagal tone. PMID:26216863

  16. Application of Bistatic TanDEM-X Interferometry to Measure Lava Flow Volume and Lava Extrusion Rates During the 2012-13 Tolbachik, Kamchatka Fissure Eruption

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2015-12-01

    Aerial imaging methods are a well approved source for mapping lava flows during eruptions and can serve as a base to assess the eruption dynamics and to determine the affected area. However, clouds and smoke often hinder optical systems like the Earth Observation Advanced Land Imager (EO-1-ALI, operated by NASA) to map lava flows properly, which hence affects its reliability. Furthermore, the amount of lava that is extruded during an eruption cannot be determined from optical images - however, it can significantly contribute to assess the accompanying hazard and risk. One way to monitor active lava flows is to quantify the topographic changes over time while using up-to-date high-resolution digital elevation models (DEMs). Whereas photogrammetric methods still fail when clouds and fume obstruct the sight, innovative radar satellite missions have the potential to generate high-resolution DEMs at any time. The innovative bistatic TanDEM-X (TerraSAR-X Add-on for Digital Elevation Measurements) satellite mission enables for the first time generating high-resolution DEMs from synthetic aperture radar satellite data repeatedly with reasonable costs and high resolution. The satellite mission consists of the two nearly identical satellites TerraSAR-X and TanDEM-X that build a large synthetic aperture radar interferometer with adaptable across- and along-track baselines aiming to generate topographic information globally. In the present study, we apply the TanDEM-X data to study the lava flows that were emplaced during the 2012-13 Tolbachik, Kamchatka fissure eruption. The eruption was composed of very fluid lava flows that effused along a northeast-southwest trending fissure. We used about fifteen bistatic data pairs to generate DEMs prior to, during, and after the eruption. The differencing of the DEMs enables mapping the lava flow field at different times. This allows measuring the extruded volume and to derive the changes in lava extrusion over time.

  17. Evaluation of treatment response in depression studies using a Bayesian parametric cure rate model.

    PubMed

    Santen, Gijs; Danhof, Meindert; Della Pasqua, Oscar

    2008-10-01

    Efficacy trials with antidepressant drugs often fail to show significant treatment effect even though efficacious treatments are investigated. This failure can, amongst other factors, be attributed to the lack of sensitivity of the statistical method as well as of the endpoints to pharmacological activity. For regulatory purposes the most widely used efficacy endpoint is still the mean change in HAM-D score at the end of the study, despite evidence from literature showing that the HAM-D scale might not be a sensitive tool to assess drug effect and that changes from baseline at the end of treatment may not reflect the extent of response. In the current study, we evaluate the prospect of applying a Bayesian parametric cure rate model (CRM) to analyse antidepressant effect in efficacy trials with paroxetine. The model is based on a survival approach, which allows for a fraction of surviving patients indefinitely after completion of treatment. Data was extracted from GlaxoSmithKline's clinical databases. Response was defined as a 50% change from baseline HAM-D at any assessment time after start of therapy. Survival times were described by a log-normal distribution and drug effect was parameterised as a covariate on the fraction of non-responders. The model was able to fit the data from different studies accurately and results show that response to treatment does not lag for two weeks, as is mythically believed. In conclusion, we demonstrate how parameterisation of a survival model can be used to characterise treatment response in depression trials. The method contrasts with the long-established snapshot on changes from baseline, as it incorporates the time course of response throughout treatment.

  18. Relations between Concurrent Longitudinal Changes in Cognition, Depressive Symptoms, Self-Rated Health and Everyday Function in Normally Aging Octogenarians

    PubMed Central

    2016-01-01

    Ability to predict and prevent incipient functional decline in older adults may help prolong independence. Cognition is related to everyday function and easily administered, sensitive cognitive tests may help identify at-risk individuals. Factors like depressive symptoms and self-rated health are also associated with functional ability and may be as important as cognition. The purpose of this study was to investigate the relationship between concurrent longitudinal changes in cognition, depression, self-rated health and everyday function in a well-defined cohort of healthy 85 year olds that were followed-up at the age of 90 in the Elderly in Linköping Screening Assessment 85 study. Regression analyses were used to determine if cognitive decline as assessed by global (the Mini-Mental State Examination) and domain specific (the Cognitive Assessment Battery, CAB) cognitive tests predicted functional decline in the context of changes in depressive symptoms and self-rated health. Results showed deterioration in most variables and as many as 83% of these community-dwelling elders experienced functional difficulties at the age of 90. Slowing-down of processing speed as assessed by the Symbol Digits Modality Test (included in the CAB) accounted for 14% of the variance in functional decline. Worsening self-rated health accounted for an additional 6%, but no other variables reached significance. These results are discussed with an eye to possible preventive interventions that may prolong independence for the steadily growing number of normally aging old-old citizens. PMID:27551749

  19. Relations between Concurrent Longitudinal Changes in Cognition, Depressive Symptoms, Self-Rated Health and Everyday Function in Normally Aging Octogenarians.

    PubMed

    Classon, Elisabet; Fällman, Katarina; Wressle, Ewa; Marcusson, Jan

    2016-01-01

    Ability to predict and prevent incipient functional decline in older adults may help prolong independence. Cognition is related to everyday function and easily administered, sensitive cognitive tests may help identify at-risk individuals. Factors like depressive symptoms and self-rated health are also associated with functional ability and may be as important as cognition. The purpose of this study was to investigate the relationship between concurrent longitudinal changes in cognition, depression, self-rated health and everyday function in a well-defined cohort of healthy 85 year olds that were followed-up at the age of 90 in the Elderly in Linköping Screening Assessment 85 study. Regression analyses were used to determine if cognitive decline as assessed by global (the Mini-Mental State Examination) and domain specific (the Cognitive Assessment Battery, CAB) cognitive tests predicted functional decline in the context of changes in depressive symptoms and self-rated health. Results showed deterioration in most variables and as many as 83% of these community-dwelling elders experienced functional difficulties at the age of 90. Slowing-down of processing speed as assessed by the Symbol Digits Modality Test (included in the CAB) accounted for 14% of the variance in functional decline. Worsening self-rated health accounted for an additional 6%, but no other variables reached significance. These results are discussed with an eye to possible preventive interventions that may prolong independence for the steadily growing number of normally aging old-old citizens. PMID:27551749

  20. Forecasting eruptions using pre-eruptive seismic patterns at Sinabung Volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    McCausland, W. A.; White, R. A.; Hendrasto, M.; Gunawan, H.; Indrastuti, N.; Triastuti, H.; Suparman, Y.; Putra, A.

    2015-12-01

    Forecasting the size, timing and style of volcanic eruptions is of primary interest to observatories and civil authorities world-wide, yet most observatories only have access to long-term data at a very limited number of volcanoes under their jurisdiction. When extensive long-term data sets are available to responsible agencies, volcanic eruptive size, timing and style can usually be successfully forecast using current monitoring data and knowledge of precursory eruptive patterns, enabling the communication of timely forecasts to civil authorities. Experienced agencies, such as Indonesia's Center for Volcanology and Geologic Hazards Mitigation and the USAID-USGS Volcano Disaster Assistance Program, utilize extensive collective experiences with multiple monitoring streams over multiple eruption cycles and across volcano types to successfully forecast eruption size, style and onset, as well as changes in eruptive style and size within ongoing eruptions. The longest-term real-time monitoring parameter commonly available at volcanoes worldwide is seismic data. Seismic data is a direct measure of rate-dependent strain changes in the magmatic system from the deep magmatic input to shallow eruptive processes. Patterns of pre-eruptive earthquakes coupled with other available monitoring data and conceptual models of magma ascent enable short-term forecasting of eruption size, style, and onset. First order event locations, characterization of background seismicity, and changes in earthquake types and energy release are most important to successful eruption forecasting. This study demonstrates how this approach has been used to successfully forecast eruption onsets, changes in eruptive style, and to change alert levels and extend or contract evacuation zones during the ongoing eruption of Sinabung Volcano, Indonesia.

  1. Filament Eruption Onset

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2011-01-01

    We have been investigating filament eruptions in recent years. Use filament eruptions as markers of the coronal field evolution. Data from SoHO, Yohkoh, TRACE, Hinode, and other sources. We and others have observed: (1)Filaments often show slow rise, followed by fast rise, (2) Brightenings, preflares, microflares during slow rise (3) Magnetic evolution in hours prior to eruption onset. We investigated What do Hinode and SDO show for filament eruptions?

  2. An erupted compound odontoma.

    PubMed

    Gupta, Anil; Vij, Hitesh; Vij, Ruchieka; Malhotra, Ritika

    2014-04-12

    Odontomas are familiar entities but their eruption into the oral cavity is an extraordinary occurrence, which may be associated with pain, infection, malocclusion, etc. Not many cases of erupted odontomas have been reported in the literature. This paper puts forth a case of erupting odontoma in an attempt to add to the list of reported cases of this unique pathology.

  3. Heart rate variability is a trait marker of major depressive disorder: evidence from the sertraline vs. electric current therapy to treat depression clinical study.

    PubMed

    Brunoni, Andre Russowsky; Kemp, Andrew H; Dantas, Eduardo M; Goulart, Alessandra C; Nunes, Maria Angélica; Boggio, Paulo S; Mill, José Geraldo; Lotufo, Paulo A; Fregni, Felipe; Benseñor, Isabela M

    2013-10-01

    Decreased heart rate variability (HRV) is a cardiovascular predictor of mortality. Recent debate has focused on whether reductions in HRV in major depressive disorder (MDD) are a consequence of the disorder or a consequence of pharmacotherapy. Here we report on the impact of transcranial direct current stimulation (tDCS), a non-pharmacological intervention, vs. sertraline to further investigate this issue. The employed design was a double-blind, randomized, factorial, placebo-controlled trial. One hundred and eighteen moderate-to-severe, medication-free, low-cardiovascular risk depressed patients were recruited for this study and allocated to either active/sham tDCS (10 consecutive sessions plus two extra sessions every other week) or placebo/sertraline (50 mg/d) for 6 wk. Patients were age and gender-matched to healthy controls from a concurrent cohort study [the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)]. The impact of disorder, treatment and clinical response on HRV (root mean square of successive differences and high frequency) was examined. Our findings confirmed that patients displayed decreased HRV relative to controls. Furthermore, HRV scores did not change following treatment with either a non-pharmacological (tDCS) or pharmacological (sertraline) intervention, nor did HRV increase with clinical response to treatment. Based on these findings, we discuss whether reduced HRV is a trait-marker for MDD, which may predispose patients to a host of conditions and disease even after response to treatment. Our findings have important implications for our understanding of depression pathophysiology and the relationship between MDD, cardiovascular disorders and mortality.

  4. Caldera development during the Minoan eruption, Thira, Cyclades, Greece

    SciTech Connect

    Heiken, G.; McCoy F. Jr.

    1984-09-30

    The well-known caldera of Thira (Santorini), Greece, was not formed during a single eruption but is composed of two overlapping calderas superimposed upon a complex volcanic field that developed along a NE trending line of vents. Before the Minoan eruption of 1400 B.C., Thira consisted of three lava shields in the northern half of the island and a flooded depression surrounded by tuff deposits in the southern half. Andesitic lavas formed the overlapping shields of the north and were contemporaneous with and, in many places, interbedded with the southern tuff deposits. Although there appears to be little difference between the composition of magmas erupted, differences in eruption style indicate that most of the activity in the northern half of the volcanic field was subaerial, producing lava flows, whereas in the south, eruptions within a flooded depression produced a sequence of mostly phreatomagmatic tuffs. Many of these tuffs are plastered onto the walls of what appears to have been an older caldera, most probably associated with an eruption of rhyodiacitic tephra 100,000 years ago. The Minoan eruption of about 1400 B.C. had four distinct phases, each reflecting a different vent geometry and eruption mechanism. The Minoan activity was preceded by minor eruptions of fine ash. (1) The eruption began with a Plinian phase, from subaerial vent(s) located on the easternmost of the lave shields. (2) Vent(s) grew toward the SW into the flooded depression. Subsequent activity deposited large-scale base surge deposits during vent widening by phreatomagnetic activity. (3) The third eruptive phase was also phreatomagmatic and produced 60% of the volume of the Minoan Tuff. This activity was nearly continuous and formed a large featureless tuff ring with poorly defined bedding.

  5. Depression and Suicidality

    ERIC Educational Resources Information Center

    Leonard, C. V.

    1974-01-01

    Suicidality ratings for 90 patients in a voluntary psychiatric hospital ward are correlated with five possible indices of depression: self-ratings of depression, Minnesota Multiphasic Personality Inventory Depression scale scores, depressive diagnosis, and alcohol and drug use. Both depression and suicidality emerges in the factor structure as…

  6. Eruption forerunners from multiparameter monitoring and application for eruptions time predictability (Piton de la Fournaise)

    NASA Astrophysics Data System (ADS)

    Schmid, A.; Grasso, J. R.; Clarke, D.; Ferrazzini, V.; BachèLery, P.; Staudacher, T.

    2012-11-01

    Volcanic eruptions impact on societal risk, and volcanic hazard assessment is a necessary ingredient for decision-makers. However, the prediction of volcanic eruptions remains challenging due to the complexity and the non-linearity of volcanic processes. Identified forerunners such as increasing seismicity or deformation of the volcanic edifice prior to eruption are not deterministic. In this study, we use statistical methods to identify and discriminate precursory patterns to eruptions, on three sets of observables of Piton de la Fournaise volcano. We analyzed the short-term (i.e. the inter-eruptive period) time series of the seismicity rate, the deformation and the seismic velocity changes (deduced from seismic noise cross-correlations) over the period 1999-2006, with two main goals. First, we characterize the average pre-eruptive time patterns before 22 eruptions using superposed epoch analysis for the three observables. Using daily rate values, we resolve (1) a velocity change within 100-50 days from the eruptions onsets, then a plateau value up to eruption onset; (2) a power law increase in seismicity rate from noise level 15-10 days before eruption time; (3) an increase of displacement rate on the eruption day. These results support a three step mechanism leading to magma transfers toward the surface. Second we use pattern recognition techniques and the formalization of error diagrams to quantify the predictive power of each forerunner either as used independently or as combined to each other. We show that when seismicity rate alone performs the best prediction in the failure to predict versus alarm duration space, the combination of the displacement and seismicity data reduces the false alarm rate. We further propose a tool which explores the prediction results in order to optimize prediction strategy for decision-makers, as a function of the risk value.

  7. Cognitive-Behavioral Intervention Increases Abstinence Rates for Depressive-History Smokers.

    ERIC Educational Resources Information Center

    Hall, Sharon M.; And Others

    1994-01-01

    Tested hypothesis that cognitive-behavioral mood management intervention would be effective for smokers with history of major depressive disorder (MDD). Findings from 149 smokers, 31% of whom had history of MDD, revealed that history-positive subjects were more likely to be abstinent when treated with mood management; treatment condition…

  8. Depression among Alumni of Foster Care: Decreasing Rates through Improvement of Experiences in Care

    ERIC Educational Resources Information Center

    White, Catherine Roller; O'Brien, Kirk; Pecora, Peter J.; English, Diana; Williams, Jason R.; Phillips, Chereese M.

    2009-01-01

    The Northwest Foster Care Alumni Study examined the relation between experiences in foster care and depression among young adults who spent at least a year in foster care as adolescents. Results indicate that preparation for leaving foster care, nurturing supports from the foster family, school stability, access to tutoring, access to therapeutic…

  9. Mothers' and Fathers' Ratings of Family Relationship Quality: Associations with Preadolescent and Adolescent Anxiety and Depressive Symptoms in a Clinical Sample

    ERIC Educational Resources Information Center

    Queen, Alexander H.; Stewart, Lindsay M.; Ehrenreich-May, Jill; Pincus, Donna B.

    2013-01-01

    This study examined the independent associations among three family relationship quality factors--cohesion, expressiveness, and conflict--with youth self-reported depressive and anxiety symptoms in a clinical sample of anxious and depressed youth. Ratings of family relationship quality were obtained through both mother and father report. The…

  10. Andesitic Plinian eruptions at Mt. Ruapehu: quantifying the uppermost limits of eruptive parameters

    NASA Astrophysics Data System (ADS)

    Pardo, Natalia; Cronin, Shane; Palmer, Alan; Procter, Jonathan; Smith, Ian

    2012-07-01

    New tephro-stratigraphic studies of the Tongariro Volcanic Centre (TgVC) on the North Island (New Zealand) allowed reconstruction of some of the largest, andesitic, explosive eruptions of Mt. Ruapehu. Large eruptions were common in the Late Pleistocene, before a transition to strombolian-vulcanian and phreatomagmatic eruptive styles that have predominated over the past 10,000 years. Considering this is the most active volcano in North Island of New Zealand and the uppermost hazard limits are unknown, we identified and mapped the pyroclastic deposits corresponding to the five largest eruptions since ~27 ka. The selected eruptive units are also characterised by distinctive lithofacies associations correlated to different behaviours of the eruptive column. In addition, we clarify the source of the ~10-9.7 ka Pahoka Tephra, identified by previous authors as the product of one of the largest eruptions of the TgVC. The most common explosive eruptions taking place between ~13.6 and ~10 ka cal years BP involved strongly oscillating, partially collapsing eruptive columns up to 37 km high, at mass discharge rates up to 6 × 108 kg/s and magnitudes of 4.9, ejecting minimum estimated volumes of 0.6 km3. Our results indicate that this volcano (as well as the neighbouring andesitic Mt. Tongariro) can generate Plinian eruptions similar in magnitude to the Chaitén 2008 and Askja 1875 events. Such eruptions would mainly produce pyroclastic fallout covering a minimum area of 1,700 km2 ESE of the volcano, where important touristic, agricultural and military activities are based. As for the 1995/1996 eruption, our field data indicate that complex wind patterns were critical in controlling the dispersion of the eruptive clouds, developing sheared, commonly bilobate plumes.

  11. The 2008 eruption of Chaitén volcano, Southern Chile: a tectonically controlled eruption?

    NASA Astrophysics Data System (ADS)

    Lara, L. E.; Pallister, J. S.; Ewert, J. W.

    2008-12-01

    The May, 2008 - present eruption at Chaitén caldera is the only example of a geophysically monitored rhyolite eruption. Geologic and seismic monitoring was conducted by the Chilean Servicio Nacional de Geología y Minería (SERNAGEOMIN) with assistance from the Volcano Disaster Assistance Program (VDAP, a joint program of USGS and OFDA). In addition, global remote sensing assets were focused on the eruption and provide extensive data on the eruptive plume and ash cloud. An initial analysis of seismic and observational monitoring and remote sensing data lead us to suggest that the Chaitén eruption was tectonically controlled, as described below. The Chaitén eruption began abruptly with Plinian ash columns (May 2-8), and then transitioned into lava dome effusion accompanied by continuous low-level ash plumes. Heights and durations of the Plinian phase of the eruption initially suggested magmatic volumes of up to as much as 1 km3, ranking this as a large VEI 4 or possibly a small VEI 5 eruption. However, reports of relatively modest thicknesses of downwind tephra indicate a smaller explosivity, probably in the moderate VEI 4 range. Extrusion of the lava dome continues at a high rate as of this time (mid-September, 2008). We estimate a lava volume of >0.3 km3 and eruption rates that have frequently exceeded 20 m3s-1, anomalously high rates for a sustained lava dome eruption. Little detailed on-site study of the proximal deposits of the eruption has been possible because of continued hazards from the eruption and austral winter weather conditions. However, several inferences about the nature of the eruption are evident. The apparent lack of historic eruptions, absence of a hydrothermal system, rapid onset of the eruption, crystal-poor rhyolite composition, lack of decompression reaction rims on amphibole crystals, and relatively high magmatic temperatures (about 860°C, as reported elsewhere in this session) all argue for rapid ascent of magma from depth. The

  12. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Bryan, Scott E.; Peate, Ingrid Ukstins; Peate, David W.; Self, Stephen; Jerram, Dougal A.; Mawby, Michael R.; Marsh, J. S. (Goonie); Miller, Jodie A.

    2010-10-01

    Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km 3 dense rock equivalent) and large-magnitude (> M8) eruptions produce areally extensive (10 4-10 5 km 2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs. Available information on the largest eruptive units are primarily from the Columbia River and Deccan provinces for the dimensions of flood basalt eruptions, and the Paraná-Etendeka and Afro-Arabian provinces for the silicic ignimbrite eruptions. In addition, three large-volume (675-2000 km 3) silicic lava flows have also been mapped out in the Proterozoic Gawler Range province (Australia), an interpreted LIP remnant. Magma volumes of > 1000 km 3 have also been emplaced as high-level basaltic and rhyolitic sills in LIPs. The data sets indicate comparable eruption magnitudes between the basaltic and silicic eruptions, but due to considerable volumes residing as co-ignimbrite ash deposits, the current volume constraints for the silicic ignimbrite eruptions may be considerably underestimated. Magma composition thus appears to be no barrier to the volume of magma emitted during an individual eruption. Despite this general similarity in magnitude, flood basaltic and silicic eruptions are very different in terms of eruption style, duration, intensity, vent configuration, and emplacement style. Flood basaltic eruptions are dominantly effusive and Hawaiian-Strombolian in style, with magma discharge rates of ~ 10 6-10 8 kg s -1 and eruption durations estimated at years to tens of years that emplace dominantly compound pahoehoe lava flow fields. Effusive and fissural eruptions have also emplaced some large-volume silicic lavas, but discharge rates are unknown, and may be up to an order of magnitude greater than those of flood basalt lava eruptions for emplacement to be on realistic time scales (< 10 years). Most

  13. Mt. Spurr's 1992 eruptions

    USGS Publications Warehouse

    1993-01-01

    On 27 June, 1992, the Crater Peak vent on the south side of Mt. Spurr awoke from 39 years of dormancy and burst into sub-plinian eruption after 10 months of elevated seismicity. Two more eruptions followed in August and September. The volcano lies 125 km west of Anchorage, Alaska's largest city and an important international hub for air travel. The Alaska Volcano Observatory (AVO) was able to warn communities and the aviation industry well in advance of these eruptions.

  14. Eruptive viscosity and volcano morphology

    NASA Technical Reports Server (NTRS)

    Posin, Seth B.; Greeley, Ronald

    1988-01-01

    Terrestrial central volcanoes formed predominantly from lava flows were classified as shields, stratovolcanoes, and domes. Shield volcanoes tend to be large in areal extent, have convex slopes, and are characterized by their resemblance to inverted hellenic war shields. Stratovolcanoes have concave slopes, whereas domes are smaller and have gentle convex slopes near the vent that increase near the perimeter. In addition to these differences in morphology, several other variations were observed. The most important is composition: shield volcanoes tend to be basaltic, stratovolcanoes tend to be andesitic, and domes tend to be dacitic. However, important exceptions include Fuji, Pico, Mayon, Izalco, and Fuego which have stratovolcano morphologies but are composed of basaltic lavas. Similarly, Ribkwo is a Kenyan shield volcano composed of trachyte and Suswa and Kilombe are shields composed of phonolite. These exceptions indicate that eruptive conditions, rather than composition, may be the primary factors that determine volcano morphology. The objective of this study is to determine the relationships, if any, between eruptive conditions (viscosity, erupted volume, and effusion rate) and effusive volcano morphology. Moreover, it is the goal of this study to incorporate these relationships into a model to predict the eruptive conditions of extraterrestrial (Martian) volcanoes based on their morphology.

  15. Effect of Cognitive Therapy With Antidepressant Medications vs Antidepressants Alone on the Rate of Recovery in Major Depressive Disorder

    PubMed Central

    Hollon, Steven D.; DeRubeis, Robert J.; Fawcett, Jan; Amsterdam, Jay D.; Shelton, Richard C.; Zajecka, John; Young, Paula R.; Gallop, Robert

    2015-01-01

    IMPORTANCE Antidepressant medication (ADM) is efficacious in the treatment of depression, but not all patients achieve remission and fewer still achieve recovery with ADM alone. OBJECTIVE To determine the effects of combining cognitive therapy (CT) with ADM vs ADM alone on remission and recovery in major depressive disorder (MDD). DESIGN, SETTING, AND PARTICIPANTS A total of 452 adult outpatients with chronic or recurrent MDD participated in a trial conducted in research clinics at 3 university medical centers in the United States. The patients were randomly assigned to ADM treatment alone or CT combined with ADM treatment. Treatment was continued for up to 42 months until recovery was achieved. INTERVENTIONS Antidepressant medication with or without CT. MAIN OUTCOMES AND MEASURES Blind evaluations of recovery with a modified version of the 17-item Hamilton Rating Scale for Depression and the Longitudinal Interval Follow-up Evaluation. RESULTS Combined treatment enhanced the rate of recovery vs treatment with ADM alone (72.6% vs 62.5%; t451 = 2.45; P = .01; hazard ratio [HR], 1.33; 95% CI, 1.06–1.68; number needed to treat [NNT], 10; 95% CI, 5–72). This effect was conditioned on interactions with severity (t451 = 1.97; P = .05; NNT, 5) and chronicity (χ2 = 7.46; P = .02; NNT, 6) such that the advantage for combined treatment was limited to patients with severe, nonchronic MDD (81.3% vs 51.7%; n = 146; t145 = 3.96; P = .001; HR, 2.34; 95% CI, 1.54–3.57; NNT, 3; 95% CI, 2–5). Fewer patients dropped out of combined treatment vs ADM treatment alone (18.9% vs 26.8%; t451 = −2.04; P = .04; HR, 0.66; 95% CI, 0.45–0.98). Remission rates did not differ significantly either as a main effect of treatment or as an interaction with severity or chronicity. Patients with comorbid Axis II disorders took longer to recover than did patients without comorbid Axis II disorders regardless of the condition (P = .01). Patients who received combined treatment reported fewer

  16. SSRI enhances sensitivity to background outcomes and modulates response rates: A randomized double blind study of instrumental action and depression.

    PubMed

    Msetfi, Rachel M; Kumar, Poornima; Harmer, Catherine J; Murphy, Robin A

    2016-05-01

    Serotonin reuptake inhibitors (SSRIs) have immediate effects on synaptic levels of serotonin but their therapeutic effects are often delayed. This delay has been suggested to reflect time required for new learning and therefore that SSRIs might be having effects on the learning process. We examined the effects of elevating serotonin levels, through short-term SSRI administration (escitalopram), on learning about perceptions of instrumental control. A randomised double blind procedure was used to allocate healthy people, categorised as mildly depressed (high BDI⩾10: n=76) or not depressed (low BDI⩽5: n=78) to either a drug (escitalopram, 10mg/7days) or placebo control group. Following treatment, participants were trained with a simple task that involved learning the effectiveness of an instrumental action (key press) and the background context at eliciting an outcome (auditory cue) where there was no programmed contingency. The effects of the drug were (i) to moderate response rates and (ii) to enhance sensitivity to the background or context rate of occurrence of the outcome. These findings suggest that serotonin modulates learning about the long-term rate of outcomes, which supports perception of instrumental control, and that this may provide a clue to the mechanism for supporting the development of the therapeutic effects of the drug. PMID:26976091

  17. How do Durkheimian variables impact variation in national suicide rates when proxies for depression and alcoholism are controlled?

    PubMed

    Fernquist, Robert M

    2007-01-01

    Sociological research on Durkheim's theories of egoistic and anomic suicide has given Durkheim continued support more than a century after Durkheim published his work. Recent criticism by Breault (1994), though, argues that Durkheim's theories of suicide actually have not been empirically supported given the lack of psychological variables included in sociological research on suicide rates. Using proxy measures of depression and alcoholism, two known psychological variables to impact suicide, as well as classic Durkheimian variables, suicide rates in eight European countries from 1973-1997 were examined. Results indicate that Durkheim's theories of egoism and anomie, while not completely supported in statistical analysis of suicide rates, received moderate support. Results suggest the continued usefulness of Durkheim's work in aggregate analyses of suicide.

  18. Thin Slice Ratings of Client Characteristics in Intake Assessments: Predicting Symptom Change and Dropout in Cognitive Therapy for Depression

    PubMed Central

    Sasso, Katherine E.; Strunk, Daniel R.

    2013-01-01

    Thin slice ratings of personality have been shown to predict a number of outcomes, but have yet to be examined in the context of psychotherapy. In a sample of 66 clients participating in cognitive therapy for depression, we examined the predictive utility of thin slice rated pre-treatment client traits. On the basis of short video clip excerpts (i.e., thin slices) of intake assessments, trained observers rated clients on personality characteristics and specific personality disorder (PD) traits. Clients’ therapy interest and neuroticism predicted lower odds of dropout. Ratings of extraversion predicted greater symptom change across treatment; ratings of clients’ Avoidant and Schizoid PD traits predicted less marked symptom improvement. Ratings of agreeableness and likeability also predicted greater symptom change, but these relations were only significant in one of two analytic approaches used. Evidence for the predictive validity of thin slice ratings was generally stronger than that observed for self-reported PD traits and PD status. Moreover, these self-report and diagnostic assessments failed to account for the thin slice-outcome relations identified. Findings support the clinical utility of quick, thin slice impressions of clients, as these ratings could be used to identify clients with a high risk of dropout or poor treatment outcome. PMID:23747583

  19. Dome forming eruptions: a global hazards database

    NASA Astrophysics Data System (ADS)

    Ogburn, S. E.; Loughlin, S.; Calder, E. S.; Ortiz, N.

    2009-12-01

    The analysis of global datasets of historical eruptions is a powerful tool for decision-making as well as for scientific discovery. Lava dome forming eruptions are common throughout the world, can extend for significant periods of time and have many associated hazards, thus providing a rich source of data to mine. A database on dome forming eruptions is under development with the view to aiding comparative studies, providing scientists with valuable data for analysis, and enabling advances in modeling of associated hazards. For new eruptive episodes in particular, and in the absence of monitoring data or a knowledge of a volcano’s eruptive history, global analysis can provide a method of understanding what might be expected based on similar eruptions in the past. Important scientific information has already been gleaned from disparate collections of dome-forming eruption hazard information, such as variation in the mobility of different types of pyroclastic flows, magma ascent and extrusion dynamics, and mechanisms of lava dome collapse. Further, modeling (both empirically-based and geophysically-based) of volcanic phenomena requires extensive data for development, calibration and validation. This study investigates the relationship between large explosive eruptions (VEI ≥ 4) and lava dome-growth from 1000 CE to present by development of a world-wide database of all relevant information, including dome growth duration, pauses between episodes of dome growth, and extrusion rates. Data sources include the database of volcanic activity maintained by the Smithsonian Institute (Global Volcanism Program) and all relevant published review papers, research papers and reports. For example, nearly all dome-forming eruptions have been associated with some level of explosive activity. Most explosions are vulcanian with eruption plumes reaching less than 15 km, and with a Volcanic Explosivity Index (VEI) <3. However large Plinian explosions with a VEI ≥ 4 can also occur

  20. Recent Two Distinct Eruptions at Sinabung and Kelud, Indonesia

    NASA Astrophysics Data System (ADS)

    Nakada, S.; Yoshimoto, M.; Maeno, F.; Iguchi, M.; Zaenudin, A.; Hendrasto, M.

    2014-12-01

    Two distinct eruptions occurred in 2014 at Sinabung and Kelud volcanoes in Indonesia. Lava dome-forming eruption started at Sinabung volcano, N Sumatra, in the end of 2013, which was preceded by the phreatic events since 2010 and shallow inflation with high seismicity since 3 months before eruption. The 2010 eruption was the first historic eruption, and the latest eruption geologically recorded occurred in the 9 to 10th Century. The eruption had continued in a nearly constant rate of magma effusion as of the summer of 2014. The lava complex extended on the SE slope (~2.5 km long from the source), frequently generating pyroclastic flows. The volume of erupted magma reached about 0.1 km3 in the 2014 summer. The lava is porphyritic andesite (SiO2 ~57%). The existence of mafic blobs in rocks and plagioclase microlites more calcic than the phenocryst rims, and the absence of breakdown rim on hornblende phenocrysts suggest magma mixing prior to eruption and relatively fast magma ascent. On the other hand, the Plinian eruption began at Kelud volcano, W Java on the evening of February 13, 2014, which had declined almost within about 6 hours. The eruption cloud rose to 18-25 km in altitude, and tephra deposited on extensive areas. The precursory seismic activity started two weeks before eruption and the intensity increased with time. This short but explosive eruption was one of recent large eruptions (VEI 4) at Kelud, which had repeated every ~20 years. A lava dome of 0.035 km3 was accidentally (?) formed within the crater in 2007-2008. The total volume of tephra of the 2014 eruption is 0.2-0.3 km3 in DRE. The magma is crystal-rich basaltic andesite (SiO2 ~56%; phenocryst proportion of ~60%). The petrological characteristics are close to the 2007-2008 dome lava except higher crystallinity in the latter. Mobilization of crystal-rich chamber magma probably was brought by intrusion of new magma. Thus, these recent examples in Indonesia are less-explosive and explosive

  1. A computer program for comprehensive ST-segment depression/heart rate analysis of the exercise ECG test.

    PubMed

    Lehtinen, R; Vänttinen, H; Sievänen, H; Malmivuo, J

    1996-06-01

    The ST-segment depression/heart rate (ST/HR) analysis has been found to improve the diagnostic accuracy of the exercise ECG test in detecting myocardial ischemia. Recently, three different continuous diagnostic variables based on the ST/HR analysis have been introduced; the ST/HR slope, the ST/HR index and the ST/HR hysteresis. The latter utilises both the exercise and recovery phases of the exercise ECG test, whereas the two former are based on the exercise phase only. This present article presents a computer program which not only calculates the above three diagnostic variables but also plots the full diagrams of ST-segment depression against heart rate during both exercise and recovery phases for each ECG lead from given ST/HR data. The program can be used in the exercise ECG diagnosis of daily clinical practice provided that the ST/HR data from the ECG measurement system can be linked to the program. At present, the main purpose of the program is to provide clinical and medical researchers with a practical tool for comprehensive clinical evaluation and development of the ST/HR analysis. PMID:8835841

  2. A computer program for comprehensive ST-segment depression/heart rate analysis of the exercise ECG test.

    PubMed

    Lehtinen, R; Vänttinen, H; Sievänen, H; Malmivuo, J

    1996-06-01

    The ST-segment depression/heart rate (ST/HR) analysis has been found to improve the diagnostic accuracy of the exercise ECG test in detecting myocardial ischemia. Recently, three different continuous diagnostic variables based on the ST/HR analysis have been introduced; the ST/HR slope, the ST/HR index and the ST/HR hysteresis. The latter utilises both the exercise and recovery phases of the exercise ECG test, whereas the two former are based on the exercise phase only. This present article presents a computer program which not only calculates the above three diagnostic variables but also plots the full diagrams of ST-segment depression against heart rate during both exercise and recovery phases for each ECG lead from given ST/HR data. The program can be used in the exercise ECG diagnosis of daily clinical practice provided that the ST/HR data from the ECG measurement system can be linked to the program. At present, the main purpose of the program is to provide clinical and medical researchers with a practical tool for comprehensive clinical evaluation and development of the ST/HR analysis.

  3. Initiation of Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.

    2007-01-01

    We consider processes occurring just prior to and at the start of the onset of flare- and CME-producing solar eruptions. Our recent work uses observations of filament motions around the time of eruption onset as a proxy for the evolution of the fields involved in the eruption. Frequently the filaments show a slow rise prior to fast eruption, indicative of a slow expansion of the field that is about co explode. Work by us and others suggests that reconnection involving emerging or canceling flux results in a lengthening of fields restraining the filament-carrying field, and the consequent upward expansion of the field in and around the filament produces the filament's slow rise: that is, the reconnection weakens the magnetic "tethers" ("tether-weakening" reconnection), and results in the slow rise of the filament. It is still inconclusive, however, what mechanism is responsible for the switch from the slow rise to the fast eruption.

  4. The Challenges of Data Rate and Data Accuracy in the Analysis of Volcanic Systems: An Assessment Using Multi-Parameter Data from the 2012-2013 Eruption Sequence at White Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Jolly, A. D.; Christenson, B. W.; Neuberg, J. W.; Fournier, N.; Mazot, A.; Kilgour, G.; Jolly, G. E.

    2014-12-01

    Volcano monitoring is usually undertaken with the collection of both automated and manual data that form a multi-parameter time-series having a wide range of sampling rates and measurement accuracies. Assessments of hazards and risks ultimately rely on incorporating this information into usable form, first for the scientists to interpret, and then for the public and relevant stakeholders. One important challenge is in building appropriate and efficient strategies to compare and interpret data from these exceptionally different datasets. The White Island volcanic system entered a new eruptive state beginning in mid-2012 and continuing through the present time. Eruptive activity during this period comprised small phreatic and phreato-magmatic events in August 2012, August 2013 and October 2013 and the intrusion of a small dome that was first observed in November 2012. We examine the chemical and geophysical dataset to assess the effects of small magma batches on the shallow hydrothermal system. The analysis incorporates high data rate (100 Hz) seismic, and infrasound data, lower data rate (1 Hz to 5 min sampling interval) GPS, tilt-meter, and gravity data and very low data rate geochemical time series (sampling intervals from days to months). The analysis is further informed by visual observations of lake level changes, geysering activity through crater lake vents, and changes in fumarolic discharges. We first focus on the problems of incorporating the range of observables into coherent time frame dependant conceptual models. We then show examples where high data rate information may be improved through new processing methods and where low data rate information may be collected more frequently without loss of fidelity. By this approach we hope to improve the accuracy and efficiency of interpretations of volcano unrest and thereby improve hazard assessments.

  5. Volcanic Eruptions and Climate

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  6. Incorporating the eruptive history in a stochastic model for volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark

    2008-08-01

    We show how a stochastic version of a general load-and-discharge model for volcanic eruptions can be implemented. The model tracks the history of the volcano through a quantity proportional to stored magma volume. Thus large eruptions can influence the activity rate for a considerable time following, rather than only the next repose as in the time-predictable model. The model can be fitted to data using point-process methods. Applied to flank eruptions of Mount Etna, it exhibits possible long-term quasi-cyclic behavior, and to Mauna Loa, a long-term decrease in activity. An extension to multiple interacting sources is outlined, which may be different eruption styles or locations, or different volcanoes. This can be used to identify an 'average interaction' between the sources. We find significant evidence that summit eruptions of Mount Etna are dependent on preceding flank eruptions, with both flank and summit eruptions being triggered by the other type. Fitted to Mauna Loa and Kilauea, the model had a marginally significant relationship between eruptions of Mauna Loa and Kilauea, consistent with the invasion of the latter's plumbing system by magma from the former.

  7. Thermal signature, eruption style, and eruption evolution at Pele and Pillan on Io

    USGS Publications Warehouse

    Davies, A.G.; Keszthelyi, L.P.; Williams, D.A.; Phillips, C.B.; McEwen, A.S.; Lopes, R.M.C.; Smythe, W.D.; Kamp, L.W.; Soderblom, L.A.; Carlson, R.W.

    2001-01-01

    The Galileo spacecraft has been periodically monitoring volcanic activity on Io since June 1996, making it possible to chart the evolution of individual eruptions. We present results of coanalysis of Near-Infrared Mapping Spectrometer (NIMS) and solid-state imaging (SSI) data of eruptions at Pele and Pillan, especially from a particularly illuminating data set consisting of mutually constraining, near-simultaneous NIMS and SSI observations obtained during orbit C9 in June 1997. The observed thermal signature from each hot spot, and the way in which the thermal signature changes with time, tightly constrains the possible styles of eruption. Pele and Pillan have very different eruption styles. From September 1996 through May 1999, Pele demonstrates an almost constant total thermal output, with thermal emission spectra indicative of a long-lived, active lava lake. The NIMS Pillan data exhibit the thermal signature of a "Pillanian" eruption style, a large, vigorous eruption with associated open channel, or sheet flows, producing an extensive flow field by orbit C10 in September 1997. The high mass eruption rate, high liquidus temperature (at least 1870 K) eruption at Pillan is the best candidate so far for an active ultramafic (magnesium-rich, "komatiitic") flow on Io, a style of eruption never before witnessed. The thermal output per unit area from Pillan is, however, consistent with the emplacement of large, open-channel flows. Magma temperature at Pele is ???1600 K. If the magma temperature is 1600 K, it suggests a komatiitic-basalt composition. The power output from Pele is indicative of a magma volumetric eruption rate of ???250 to 340 m3 s-1. Although the Pele lava lake is considerably larger than its terrestrial counterparts, the power and mass fluxes per unit area are similar to active terrestrial lava lakes. Copyright 2001 by the American Geophysical Union.

  8. Ten Years Record of Decreasing Heat Output From the Hyaloclastite Ridge Formed in the 1996 Gjalp Eruption

    NASA Astrophysics Data System (ADS)

    Gudmundsson, M. T.; Jarosch, A. H.; Högnadottir, T.

    2006-12-01

    The Gjálp eruption in 1996 formed a 6 km long and 500 m high subglacial hyaloclastite ridge. During the eruption a large depression was formed in the surface of the Vatnajökull ice cap as ice was melted and the meltwater drained away from the eruption site. Ice flow measurements and surface depression mapping have been done annually since the eruption, allowing inflow of ice and volume changes of the depression to be monitored. Taking into account the surface mass balance, these data can be used to estimate heat output from the subglacial ridge. The inflow of ice into the depression mainly from the north is an important part of the overall mass balance budget and was estimated combining surface velocities measurements with numerical 2D, full Stokes, ice flow models. In the first year after the eruption a heat flux of several thousand megawatts was estimated. The heat output decreased to several hundred MW in 1998 and this order of magnitude persisted until 2002. However after 2002 the mountain cooled down and from 2002 to 2005 heat output of the order 101 MW was obtained. These results indicate a 5 - 6 years period with major geothermal activity in the ridge, while in the last 4 years the ridge appears to be much colder. Since the ridge is fully covered by ice, no direct measurements of observations are available to explain this thermal record. Ridges of similar size and shape to that of Gjálp are a prominent feature of the volcanic zones in Iceland. A prominent part of these ridges are consolidated hyaloclastite, formed by alteration of the volcanic glass into palagonite. The rate at which this alteration takes place for ridges formed in short-lived subglacial eruptions is unknown. However, in most cases they have acquired considerable consolidation before glacial erosion could remove the initially unconsolidated hyaloclastite pile. In the oceanic island of Surtsey formed in 1963-1967, the rate of alteration was temperature dependent and took a few years. It is

  9. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

    This study assessed the effect of extraction and preservation of the 1st premolar on lower 3rd molar eruption. Orthodontic clinic records from 1993 to 1995 were evaluated before and after treatment and 8-9 years after treatment for 3 groups of patients: 32 with extraction of 1st premolars in both jaws, 32 with no extraction but orthodontic treatment and 48 controls with no extraction but orthodontic treatment in the upper jaws only. Successful eruption of 3rd molars was evaluated. There was a significant difference in the rates of successful eruptions in the extraction (42%), non-extraction (12%) and control (20%) groups. The findings indicate that 1st premolar extraction may increase the chance of 3rd molar eruption, leading to a lower incidence of health and economic complications.

  10. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

    This study assessed the effect of extraction and preservation of the 1st premolar on lower 3rd molar eruption. Orthodontic clinic records from 1993 to 1995 were evaluated before and after treatment and 8-9 years after treatment for 3 groups of patients: 32 with extraction of 1st premolars in both jaws, 32 with no extraction but orthodontic treatment and 48 controls with no extraction but orthodontic treatment in the upper jaws only. Successful eruption of 3rd molars was evaluated. There was a significant difference in the rates of successful eruptions in the extraction (42%), non-extraction (12%) and control (20%) groups. The findings indicate that 1st premolar extraction may increase the chance of 3rd molar eruption, leading to a lower incidence of health and economic complications. PMID:19161121

  11. Interacting filamentary eruptions in magnetised plasmas

    NASA Astrophysics Data System (ADS)

    Henneberg, S. A.; Cowley, S. C.; Wilson, H. R.

    2015-12-01

    The interaction between multiple filamentary plasma eruptions is investigated by modelling the non-linear ideal MHD ballooning mode envelope equation with a mixed Eulerian and Lagrangian characterisation of the boundary conditions. The study of multiple plasma filaments is performed in a specific slab equilibrium susceptible to Rayleigh-Taylor instabilities. If the unstable system is initiated with three equal sized filaments, they erupt at the same rate, independently of each other, even in the non-linear regime. However, if one is initiated very slightly larger than the other two it causes a down-draft as it erupts upwards, which suppresses the smaller filaments. This suggests that those filaments which first enter the non-linear regime will dominate the plasma eruption dynamics.

  12. Affective forecasting and self-rated symptoms of depression, anxiety, and hypomania: evidence for a dysphoric forecasting bias.

    PubMed

    Hoerger, Michael; Quirk, Stuart W; Chapman, Benjamin P; Duberstein, Paul R

    2012-01-01

    Emerging research has examined individual differences in affective forecasting; however, we are aware of no published study to date linking psychopathology symptoms to affective forecasting problems. Pitting cognitive theory against depressive realism theory, we examined whether dysphoria was associated with negatively biased affective forecasts or greater accuracy. Participants (n=325) supplied predicted and actual emotional reactions for three days surrounding an emotionally evocative relational event, Valentine's Day. Predictions were made a month prior to the holiday. Consistent with cognitive theory, we found evidence for a dysphoric forecasting bias-the tendency of individuals in dysphoric states to overpredict negative emotional reactions to future events. The dysphoric forecasting bias was robust across ratings of positive and negative affect, forecasts for pleasant and unpleasant scenarios, continuous and categorical operationalisations of dysphoria, and three time points of observation. Similar biases were not observed in analyses examining the independent effects of anxiety and hypomania. Findings provide empirical evidence for the long-assumed influence of depressive symptoms on future expectations. The present investigation has implications for affective forecasting studies examining information-processing constructs, decision making, and broader domains of psychopathology.

  13. Development and validation of the Dimensional Anhedonia Rating Scale (DARS) in a community sample and individuals with major depression.

    PubMed

    Rizvi, Sakina J; Quilty, Lena C; Sproule, Beth A; Cyriac, Anna; Michael Bagby, R; Kennedy, Sidney H

    2015-09-30

    Anhedonia, a core symptom of Major Depressive Disorder (MDD), is predictive of antidepressant non-response. In contrast to the definition of anhedonia as a "loss of pleasure", neuropsychological studies provide evidence for multiple facets of hedonic function. The aim of the current study was to develop and validate the Dimensional Anhedonia Rating Scale (DARS), a dynamic scale that measures desire, motivation, effort and consummatory pleasure across hedonic domains. Following item selection procedures and reliability testing using data from community participants (N=229) (Study 1), the 17-item scale was validated in an online study with community participants (N=150) (Study 2). The DARS was also validated in unipolar or bipolar depressed patients (n=52) and controls (n=50) (Study 3). Principal components analysis of the 17-item DARS revealed a 4-component structure mapping onto the domains of anhedonia: hobbies, food/drink, social activities, and sensory experience. Reliability of the DARS subscales was high across studies (Cronbach's α=0.75-0.92). The DARS also demonstrated good convergent and divergent validity. Hierarchical regression analysis revealed the DARS showed additional utility over the Snaith-Hamilton Pleasure Scale (SHAPS) in predicting reward function and distinguishing MDD subgroups. These studies provide support for the reliability and validity of the DARS. PMID:26250147

  14. Characterization of depressive States in bipolar patients using wearable textile technology and instantaneous heart rate variability assessment.

    PubMed

    Valenza, Gaetano; Citi, Luca; Gentili, Claudio; Lanata, Antonio; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2015-01-01

    The analysis of cognitive and autonomic responses to emotionally relevant stimuli could provide a viable solution for the automatic recognition of different mood states, both in normal and pathological conditions. In this study, we present a methodological application describing a novel system based on wearable textile technology and instantaneous nonlinear heart rate variability assessment, able to characterize the autonomic status of bipolar patients by considering only electrocardiogram recordings. As a proof of this concept, our study presents results obtained from eight bipolar patients during their normal daily activities and being elicited according to a specific emotional protocol through the presentation of emotionally relevant pictures. Linear and nonlinear features were computed using a novel point-process-based nonlinear autoregressive integrative model and compared with traditional algorithmic methods. The estimated indices were used as the input of a multilayer perceptron to discriminate the depressive from the euthymic status. Results show that our system achieves much higher accuracy than the traditional techniques. Moreover, the inclusion of instantaneous higher order spectra features significantly improves the accuracy in successfully recognizing depression from euthymia.

  15. Sympathetic Solar Filament Eruptions

    NASA Astrophysics Data System (ADS)

    Wang, Rui; Liu, Ying D.; Zimovets, Ivan; Hu, Huidong; Dai, Xinghua; Yang, Zhongwei

    2016-08-01

    The 2015 March 15 coronal mass ejection as one of the two that together drove the largest geomagnetic storm of solar cycle 24 so far was associated with sympathetic filament eruptions. We investigate the relations between the different filaments involved in the eruption. A surge-like small-scale filament motion is confirmed as the trigger that initiated the erupting filament with multi-wavelength observations and using a forced magnetic field extrapolation method. When the erupting filament moved to an open magnetic field region, it experienced an obvious acceleration process and was accompanied by a C-class flare and the rise of another larger filament that eventually failed to erupt. We measure the decay index of the background magnetic field, which presents a critical height of 118 Mm. Combining with a potential field source surface extrapolation method, we analyze the distributions of the large-scale magnetic field, which indicates that the open magnetic field region may provide a favorable condition for F2 rapid acceleration and have some relation with the largest solar storm. The comparison between the successful and failed filament eruptions suggests that the confining magnetic field plays an important role in the preconditions for an eruption.

  16. Solar Prominence Eruption

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.

    1998-01-01

    The prominence that erupts in a prominence eruption is a magnetic structure in the chromosphere and corona. It is visible in chromospheric images by virtue of chromospheric-temperature plasma suspended in the magnetic field, and belongs to that large class of magnetic structures appropriately called filaments because of their characteristic sinewy sigmoidal form. Hence, the term "filament eruption" is used interchangeably with the term "prominence eruption". The magnetic field holding a filament is prone to undergo explosive changes in configuration. In these upheavals, because the filament material is compelled by its high conductivity to ride with the magnetic field that threads it, this material is a visible tracer of the field motion. The part of the magnetic explosion displayed by the entrained filament material is the phenomenon known as a filament eruption, the topic of this article. This article begins with a description of basic observed characteristics of filament eruptions, with attention to the magnetic fields, flares, and coronal mass ejections in which erupting filaments are embedded. The present understanding of these characteristics in terms of the form and action of the magnetic field is then laid out by means of a rudimentary three-dimensional model of the field. The article ends with basic questions that this picture leaves unresolved and with remarks on the observations needed to probe these questions.

  17. Using anchoring vignettes to assess the comparability of self-rated feelings of sadness, lowness or depression in France and Vietnam.

    PubMed

    Guindon, G Emmanuel; Boyle, Michael H

    2012-03-01

    General measures of self-rated health are collected routinely in national health surveys and widely used in the analyses of determinants of health and health care utilization. However, these subjective assessments can be influenced by health expectations (contextualized beliefs about health) that may vary systematically across individuals and be associated with their socio-demographic characteristics. Our objective is to contrast the impact of health expectations associated with respondent characteristics (reporting heterogeneity) on self-rated feelings of sadness, lowness or depression obtained from general population samples in France and Vietnam. Based on self ratings and ratings in response to common anchoring vignettes depicting different levels of depression, we used nationally representative data from the World Health Survey conducted in France (2002) and Vietnam (2002-2003) and a modification of the standard probit model to test and adjust for reporting heterogeneity associated with individual characteristics. We find evidence of reporting heterogeneity within France and Vietnam and across the two countries. In particular we find that, when adjusted for reporting heterogeneity, sex is no longer significantly associated with self-rated feelings of sadness, lowness or depression in France. Given the absence of clear biological markers in the definitions of depressive disorders and the substantial impact reporting heterogeneity is shown to have, measures of depressive disorders based on self-reports should be interpreted with caution.

  18. Treatment-Resistant Depressed Youth Show a Higher Response Rate If Treatment Ends during Summer School Break

    ERIC Educational Resources Information Center

    Shamseddeen, Wael; Clarke, Gregory; Wagner, Karen Dineen; Ryan, Neal D.; Birmaher, Boris; Emslie, Graham; Asarnow, Joan Rosenbaum; Porta, Giovanna; Mayes, Taryn; Keller, Martin B.; Brent, David A.

    2011-01-01

    Objective: There is little work on the effect of school on response to treatment of depression, with available research suggesting that children and adolescents with school difficulties are less likely to respond to fluoxetine compared with those with no school difficulties. Method: Depressed adolescents in the Treatment of Resistant Depression in…

  19. An Erupted Silent Tumour.

    PubMed

    Kudva, Adarsh; Chithra, A; Rao, Nirmala N; Cariappa, K M

    2016-07-01

    Odontomas are the most common odontogenic tumors of the oral cavity which are nonaggressive, hamartomatous in nature consisting of enamel, dentin and cementum. They are called as composite because they contain more than one type of tissue. They are generally asymptomatic, hence recognised on routine radiologic examination. The compound odontoma is composed of multiple small tooth like structures, whereas the complex odontoma consists of a conglomerate mass of enamel and dentine, which bears no anatomical similarity to the tooth. The eruption and infection of odontoma are uncommon, only few cases of erupted complex odontoma are reported in the literature. We report a case of silent erupting complex odontoma. PMID:27408461

  20. Assessment of Holocene soil erosion rates on the loess plateau in East Poland using sedimentary archives from closed depressions

    NASA Astrophysics Data System (ADS)

    Kołodyńska-Gawrysiak, Renata; Poesen, Jean; Gawrysiak, Leszek

    2016-04-01

    Closed depressions (CDs) are typical geomorphological features of the European loess belt. They are closed sedimentation basins that enable the estimation of long-term soil erosion rates for different land use environments. This study was conducted in eastern Poland (Nałęczów Plateau). In this region CDs are rather small landforms and the area of 70% of all CDs does not exceed 1500 m2. The study objective was to assess Holocene soil erosion rates in the loess plateau based on a quantitative analysis of colluvial sediments deposited in CDs. Two representative CDs were selected for this study: one CD is located in an old (long-term) forest and the other is situated in a long-term agricultural land. The maximum depth of the CD in the forest, the mean slope gradient and area of the corresponding catchment are 4.9 m, 3.410 and 7568 m² respectively. For the CD in agricultural land these values are 3.2 m, 2.760 and 5156 m² respectively. In both CDs several dozen of drillings and two trenches (2 m long, 1m wide, 2 m deep) were made in the deepest point of the CDs. Mean long-term soil erosion rates were calculated based on the stratigraphy of the soil-sediment sequence infilling the CDs. C-14 and OSL datings of soils and colluvial sediments within the CDs were obtained. For the long-term agricultural used catchment of the CD it was calculated that since 6.31 ± 0.35 ka BP the mean annual soil loss due to water and tillage erosion is 0.63-0.7 t/ha/year or 279.3 mm. In the prehistoric period since 6.31 ± 0.35 ka BP until 1026-1162 AD the mean annual soil erosion rate amounted to 0,10-0.11 t/ha/year or 41.5 mm. During the last ca. 1000 years mean soil erosion rates increased to 3.99-4.63 t/ha/year or 249.2 mm. Results of long-term soil erosion rates (calculated using colluvial sediment sequences in CDs) from agricultural catchments in the loess regions of eastern Poland (this study) and Central Belgium (Gillijns et al. 2005) are quite similar. For the forested catchment

  1. Eruption and degassing dynamics of the major August 2015 Piton de la Fournaise eruption

    NASA Astrophysics Data System (ADS)

    Di Muro, Andrea; Arellano, Santiago; Aiuppa, Alessandro; Bachelery, Patrick; Boudoire, Guillaume; Coppola, Diego; Ferrazzini, Valerie; Galle, Bo; Giudice, Gaetano; Gurioli, Lucia; Harris, Andy; Liuzzo, Marco; Metrich, Nicole; Moune, Severine; Peltier, Aline; Villeneuve, Nicolas; Vlastelic, Ivan

    2016-04-01

    Piton de la Fournaise (PdF) shield volcano is one of the most active basaltic volcanoes in the World with one eruption every nine months, on average. This frequent volcanic activity is broadly bimodal, with frequent small volume, short lived eruptions (< 30 Mm3, most being < 10 Mm3) and less frequent relatively large (50-210 Mm3) and long lasting (months) eruptions. After the major caldera forming event of 2007, the volcano produced several short lived small volume summit to proximal eruptions of relatively evolved cotectic magmas and relatively long repose periods (up to 3.5 years between 2010 and 2014). The August 2015 eruption was the first large (45±15 Mm3) and long lasting (2 months) eruption since 2007 and the only event to be fully monitored by the new gas geochemical network of Piton de la Fournaise volcanological observatory (DOAS, MultiGaS, diffuse CO2 soil emissions). Regular lava and tephra sampling was also performed for geochemical and petrological analysis. The eruption was preceded by a significant increase in CO2 soil emissions at distal soil stations (ca. 15 km from the summit), with CO2 enrichment also being recorded at summit low temperature fumaroles. Eruptive products were spectacularly zoned, with plagioclase and pyroxene being abundant in the early erupted products and olivine being the main phase in the late-erupted lavas. Total gas emissions at the eruptive vent underwent a decrease during the first half of the eruption and then an increase, mirroring the time evolution of magma discharge rate (from 5-10 m3/s in September to 15-30 m3/s in late-October) and the progressive change in magma composition. In spite of significant evolution in magma and gas output, CO2/SO2 ratios in high temperature gases remained quite low (< 0.3) and with little temporal change. Geochemical data indicated that this relatively long-lived eruption corresponded to the progressive drainage of most of the shallow part of PdF plumbing system, triggered by a new

  2. Snake Filament Eruption

    NASA Video Gallery

    A very long solar filament that had been snaking around the Sun erupted on Dec. 6, 2010 with a flourish. NASA's Solar Dynamics Observatory (SDO) caught the action in dramatic detail in extreme ultr...

  3. Triple Solar Eruption

    NASA Video Gallery

    Solar activity surged on the morning of Dec 12, 2010 when the sun erupted three times in quick succession, hurling a trio of bright coronal mass ejections (CMEs) into space. Coronagraphs onboard th...

  4. GENERALIZED ERUPTIVE SYRINGOMAS

    PubMed Central

    Jamalipour, Mahnaz; Heidarpour, Mitra; Rajabi, Parvin

    2009-01-01

    Generalized eruptive syringoma is a rare clinical presentation of a benign adnexal tumor that derives from the intraepidermal portion of the eccrine sweat ducts. It presents as successive crops of small flesh-colored papules on the anterior body surfaces. It generally occurs in the peripubertal period. Treatment of this benign condition is cosmetic only. A case of a 28-year-old female with an eight-year history of eruptive syringoma is presented. PMID:20049275

  5. A Nanolite Record of Eruption Style Transition

    NASA Astrophysics Data System (ADS)

    Mujin, M.; Nakamura, M.

    2014-12-01

    Microlites in pyroclasts have been intensively studied to understand magma ascent processes. However, microlites do not record the explosive-effusive transitions in sub-Plinian eruptions when such transitions are governed by the shallow level degassing rather than by the magma ascent rate. To overcome this limitation, we studied the "nanolites" in the quenched products of the 2011 Shinmoedake, Kirishima Volcanic Group, Kyusyu Japan1. Nanolites are the nanometer-scale components of the groundmass minerals and exhibit a steeper slope of crystal size distribution than that of the microlites2. In the 2011 Shinmoedake eruption, the style of activity had undergone transformations from sub-Plinian eruption to Vulcanian explosion and intermittent effusion of lava3. We found that, although the products formed by different eruptive activities have similar microlite characteristics, such products can be distinguished clearly by their mineral assemblage of nanolites. The samples of pumices of sub-Plinian eruptions and Vulcanian explosions and the dense juvenile fragments of lava (in descending order of explosivity) contained, respectively, nanolites of low-Ca pyroxene, low-Ca pyroxene + plagioclase, and low-Ca pyroxene + plagioclase + Fe-Ti oxides. Nanolites are assumed to crystallize when undercooling of the magma due primarily to dehydration increases rapidly near the surface. The water contents of the interstitial glass indicate that the quenched depths did not differ greatly between eruption styles. Hence, the different nanolite assemblages of each eruption style are assumed to have resulted from differences in magma residence time near the surface. Thus, we propose that nanolites in pyroclasts have the potential to indicate the physicochemical conditions of magma at the transition points of eruption styles. References 1) Mujin and Nakamura, 2014, Geology, v.42, p.611-614 2) Sharp et al., 1996, Bull. Volcanol, v.57, p.631-640 3) Miyabuchi et al, 2013, J. Volcanol

  6. Deformation associated with the 1997 eruption of Okmok volcano, Alaska

    USGS Publications Warehouse

    Mann, Dorte; Freymueller, Jeffrey T.; Lu, Zhiming

    2002-01-01

    Okmok volcano, located on Umnak Island in the Aleutian chain, Alaska, is the most eruptive caldera system in North America in historic time. Its most recent eruption occurred in 1997. Synthetic aperture radar interferometry shows deflation of the caldera center of up to 140 cm during this time, preceded and followed by inflation of smaller magnitude. The main part of the observed deformation can be modeled using a pressure point source model. The inferred source is located between 2.5 and 5.0 km beneath the approximate center of the caldera and ???5 km from the eruptive vent. We interpret it as a central magma reservoir. The preeruptive period features inflation accompanied by shallow localized subsidence between the caldera center and the vent. We hypothesize that this is caused by hydrothermal activity or that magma moved away from the central chamber and toward the later vent. Since all historic eruptions at Okmok have originated from the same cone, this feature may be a precursor that indicates an upcoming eruption. The erupted magma volume is ???9 times the volume that can be accounted for by the observed preeruptive inflation. This indicates a much longer inflation interval than we were able to observe. The observation that reinflation started shortly after the eruption suggests that inflation spans the whole time interval between eruptions. Extrapolation of the average subsurface volume change rate is in good agreement with the long-term eruption frequency and eruption volumes of Okmok.

  7. Incidence rates of suicidal behaviors and treated depression in patients with and without psoriatic arthritis using the Clinical Practice Research Datalink

    PubMed Central

    Hagberg, Katrina Wilcox; Li, Lin; Peng, Michael; Shah, Kamal; Paris, Maria; Jick, Susan

    2016-01-01

    Abstract Objective: To estimate rates of suicidal behaviors and treated depression in patients with psoriatic arthritis (PsA) in comparison to non-PsA patients. Methods: Using the Clinical Practice Research Datalink, we conducted a cohort study of patients with PsA compared to non-PsA patients. Patients with codes for suicidal behaviors (ideation, attempts, and suicide) and treated depression (diagnosis plus anti-depressant prescription) recorded during follow-up were identified as cases. We estimated incidence rates (IRs) and incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for each outcome and stratified results in the PsA cohort by receipt of systemic PsA drugs. Results: The rates of suicide ideation, attempt, and suicide were similar for PsA and non-PsA patients [IRR = 0.99 (95%CI: 0.67–1.47), IRR = 1.07 (95%CI: 0.86–1.34), and 0.34 (95%CI: 0.05–2.48), respectively] and rates of suicidal behaviors were slightly higher among PsA patients who received PsA drugs compared to those who did not. PsA patients had slightly higher rate of treated depression compared to non-PsA patients [IRR = 1.38 (95%CI: 1.27–1.49)] and were significantly higher in PsA patients who received drugs [IRR = 1.59 (95%CI: 1.35–1.86)]. Conclusions: Rate of depression was higher in patients with PsA compared to non-PsA patients. The rate of suicidal behaviors was similar between the two cohorts. PMID:26882216

  8. Interrater Reliability of mHealth App Rating Measures: Analysis of Top Depression and Smoking Cessation Apps

    PubMed Central

    Chan, Steven; Raynor, Geoffrey Stephen; Shwarts, Erik; Shanahan, Meghan; Landman, Adam B

    2016-01-01

    Background There are over 165,000 mHealth apps currently available to patients, but few have undergone an external quality review. Furthermore, no standardized review method exists, and little has been done to examine the consistency of the evaluation systems themselves. Objective We sought to determine which measures for evaluating the quality of mHealth apps have the greatest interrater reliability. Methods We identified 22 measures for evaluating the quality of apps from the literature. A panel of 6 reviewers reviewed the top 10 depression apps and 10 smoking cessation apps from the Apple iTunes App Store on these measures. Krippendorff’s alpha was calculated for each of the measures and reported by app category and in aggregate. Results The measure for interactiveness and feedback was found to have the greatest overall interrater reliability (alpha=.69). Presence of password protection (alpha=.65), whether the app was uploaded by a health care agency (alpha=.63), the number of consumer ratings (alpha=.59), and several other measures had moderate interrater reliability (alphas>.5). There was the least agreement over whether apps had errors or performance issues (alpha=.15), stated advertising policies (alpha=.16), and were easy to use (alpha=.18). There were substantial differences in the interrater reliabilities of a number of measures when they were applied to depression versus smoking apps. Conclusions We found wide variation in the interrater reliability of measures used to evaluate apps, and some measures are more robust across categories of apps than others. The measures with the highest degree of interrater reliability tended to be those that involved the least rater discretion. Clinical quality measures such as effectiveness, ease of use, and performance had relatively poor interrater reliability. Subsequent research is needed to determine consistent means for evaluating the performance of apps. Patients and clinicians should consider conducting their

  9. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  10. Submarine Silicic Explosive Eruptions: what can submarine pyroclasts tell us?

    NASA Astrophysics Data System (ADS)

    Carey, R.; Allen, S.; McPhie, J.; Fiske, R. S.; Tani, K.

    2014-12-01

    Our understanding of submarine volcanism is in its infancy with respect to subaerial eruption processes. Two fundamental differences between eruptions in seawater compared to those on land are that (1) eruptions occur at higher confining pressures, and (2) in a seawater medium, which has a higher heat capacity, density and viscosity than air. Together with JAMSTEC collaborators we have a sample suite of submarine pumice deposits from modern volcanoes of known eruption depths. This sample suite spans a spectrum of eruption intensities, from 1) powerful explosive caldera-forming (Myojin Knoll caldera); to 2) weakly explosive cone building (pre-caldera Myojin Knoll pumice and Kurose-Nishi pumice); to 3) volatile-driven effusive dome spalling (Sumisu knoll A); to 4) passive dome effusion (Sumisu knoll B and C). This sample suite has exceptional potential, not simply because the samples have been taken from well-constrained, sources but because they have similar high silica contents, are unaltered and their phenocrysts contain melt inclusions. Microtextural quantitative analysis has revealed that (i) clast vesicularities remain high (69-90 vol.%) regardless of confining pressure, mass eruption rate or eruption style , (ii) vesicle number densities scale with inferred eruption rate, and (iii) darcian and inertial permeabilities of submarine effusive and explosive pyroclasts overlap with explosively-erupted subaerial pyroclasts.

  11. Failed magmatic eruptions: Late-stage cessation of magma ascent

    USGS Publications Warehouse

    Moran, S.C.; Newhall, C.; Roman, D.C.

    2011-01-01

    When a volcano becomes restless, a primary question is whether the unrest will lead to an eruption. Here we recognize four possible outcomes of a magmatic intrusion: "deep intrusion", "shallow intrusion", "sluggish/viscous magmatic eruption", and "rapid, often explosive magmatic eruption". We define "failed eruptions" as instances in which magma reaches but does not pass the "shallow intrusion" stage, i. e., when magma gets close to, but does not reach, the surface. Competing factors act to promote or hinder the eventual eruption of a magma intrusion. Fresh intrusion from depth, high magma gas content, rapid ascent rates that leave little time for enroute degassing, opening of pathways, and sudden decompression near the surface all act to promote eruption, whereas decreased magma supply from depth, slow ascent, significant enroute degassing and associated increases in viscosity, and impingement on structural barriers all act to hinder eruption. All of these factors interact in complex ways with variable results, but often cause magma to stall at some depth before reaching the surface. Although certain precursory phenomena, such as rapidly escalating seismic swarms or rates of degassing or deformation, are good indicators that an eruption is likely, such phenomena have also been observed in association with intrusions that have ultimately failed to erupt. A perpetual difficulty with quantifying the probability of eruption is a lack of data, particularly on instances of failed eruptions. This difficulty is being addressed in part through the WOVOdat database. Papers in this volume will be an additional resource for scientists grappling with the issue of whether or not an episode of unrest will lead to a magmatic eruption.

  12. Late-stage stretching and subsidence rates in the Danakil Depression, evidenced from borehole records and seismic reflection data

    NASA Astrophysics Data System (ADS)

    Booth, Adam; Bastow, Ian; Magee, Craig; Keir, Derek; Corti, Giacomo; Jackson, Chris; Wilkinson, Jason

    2016-04-01

    The Ethiopian and Afar Rift systems provide a globally unique opportunity to study the incipient transition from continental rifting to sea-floor spreading. A consensus has emerged that a considerable proportion of plate extension in Ethiopia is accommodated by dyke intrusion, with smaller contributions from crustal thinning. However, observations of thinned crust and a pulse in Quaternary-Recent basaltic volcanism within Ethiopia's Danakil Depression have been cited (Bastow and Keir, 2011) as evidence that localised plate stretching may mark the final stages of continent-ocean transition. We explore this hypothesis using an archive of five 2-D seismic reflection profiles, each between 7-10 km in length, and ˜120 borehole records distributed over an area of 225 km2. From depth and age relationships of key marker horizons, we also suggest local subsidence and extension rates. The borehole archive reveals extensive evaporite sequences deposited in and around an asymmetric basin, bounded to the west by a network of east-dipping normal faults. West of the basin, the maximum observed thickness of evaporites is 150 m, beneath which are deposits of clastic sediment, but a sequence of evaporites at least 900 m thick is observed at the basin centre. The sedimentary architecture of these sequences suggests deposition in a shallow salt-pan environment, with seasonal - potentially diurnal - freshening of the brine supply (Warren, 2012). Isotopic analysis of reef carbonates in the basin flank dates the last marine incursion into the Danakil Depression at 24-230ka (Lalou et al., 1970; Bonatti et al., 1971; Bannert et al., 1971), therefore the evaporite sequence must be younger than this. A key marker horizon within the evaporites is the potash-bearing Houston Formation, also distinct in borehole records given its high porosity (25-40%) and radioactivity (50-250 API units). The elevation of the Houston Formation is ˜500 m deeper in the centre of the basin than on the flank

  13. Late-stage stretching and subsidence rates in the Danakil Depression, evidenced from borehole records and seismic reflection data

    NASA Astrophysics Data System (ADS)

    Booth, Adam; Bastow, Ian; Magee, Craig; Keir, Derek; Corti, Giacomo; Jackson, Chris; Wilkinson, Jason

    2016-04-01

    The Ethiopian and Afar Rift systems provide a globally unique opportunity to study the incipient transition from continental rifting to sea-floor spreading. A consensus has emerged that a considerable proportion of plate extension in Ethiopia is accommodated by dyke intrusion, with smaller contributions from crustal thinning. However, observations of thinned crust and a pulse in Quaternary-Recent basaltic volcanism within Ethiopia's Danakil Depression have been cited (Bastow and Keir, 2011) as evidence that localised plate stretching may mark the final stages of continent-ocean transition. We explore this hypothesis using an archive of five 2-D seismic reflection profiles, each between 7-10 km in length, and ˜120 borehole records distributed over an area of 225 km2. From depth and age relationships of key marker horizons, we also suggest local subsidence and extension rates. The borehole archive reveals extensive evaporite sequences deposited in and around an asymmetric basin, bounded to the west by a network of east-dipping normal faults. West of the basin, the maximum observed thickness of evaporites is 150 m, beneath which are deposits of clastic sediment, but a sequence of evaporites at least 900 m thick is observed at the basin centre. The sedimentary architecture of these sequences suggests deposition in a shallow salt-pan environment, with seasonal - potentially diurnal - freshening of the brine supply (Warren, 2012). Isotopic analysis of reef carbonates in the basin flank dates the last marine incursion into the Danakil Depression at 24-230ka (Lalou et al., 1970; Bonatti et al., 1971; Bannert et al., 1971), therefore the evaporite sequence must be younger than this. A key marker horizon within the evaporites is the potash-bearing Houston Formation, also distinct in borehole records given its high porosity (25-40%) and radioactivity (50-250 API units). The elevation of the Houston Formation is ˜500 m deeper in the centre of the basin than on the flank

  14. Volcanic eruptions on Io

    NASA Astrophysics Data System (ADS)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  15. Eruption column physics

    SciTech Connect

    Valentine, G.A.

    1997-03-01

    In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

  16. Voltage- and time-dependent depression of maximum rate of depolarization of guinea-pig ventricular action potentials by two steroidal antiarrhythmic drugs, CCI 22277 and ORG 6001.

    PubMed

    Campbell, T J

    1982-11-01

    1 The voltage- and time-dependence of the depression of the maximum rate of depolarization (Vmax) by two steroidal anti-arrhythmic drugs, CCI22277 and Org 6001 were studied in guinea-pig ventricle. 2 At normal resting potentials CCI22277 (2 microM and 4 microM) produced very little depression of Vmax at very low driving rates (resting block) but trains of stimuli at interstimulus intervals (ISI) of less than 10,000 ms led to an exponential decline in Vmax to a new plateau over 100-200 beats. 3 This 'rate-dependent block' (RDB) increased with rate over the range ISI=4800 to ISI=200 ms. 4 Org 6001 30 microM and 60 microM produced a similar degree of RDB over the same range of frequencies but the new plateau level of Vmax was reached much more rapidly (20-30 beats) and there was a moderate degree of depression of Vmax in the resting tissue. 5 Recovery from RDB in the presence of both drugs was an exponential process with time constants (tau re) of 80.4 +/- 7.4 s for CCI22277 and 4.6 +/- 0.5 s for Org 6001. 6 Both drugs shifted the steady-state inactivation curve, relating Vmax to resting membrane potential, in the hyperpolarizing direction, implying selective depression of depolarized cells.

  17. The Diagnostic Drawing Series and the Tree Rating Scale: An Isomorphic Representation of Multiple Personality Disorder, Major Depression, and Schizophrenic Populations.

    ERIC Educational Resources Information Center

    Morris, Maureen Batza

    1995-01-01

    The tree drawings of 80 subjects, who were diagnosed with either multiple personality disorder, schizophrenia, or major depression, and a control group, were rated. Patterns were examined and graphs were used to depict results. Certain features were found to distinguish each category. The descriptive statistical findings were both consistent and…

  18. Differentiation of women with premenstrual dysphoric disorder, recurrent brief depression, and healthy controls by daily mood rating dynamics.

    PubMed

    Pincus, Steven M; Schmidt, Peter J; Palladino-Negro, Paula; Rubinow, David R

    2008-04-01

    Enhanced statistical characterization of mood-rating data holds the potential to more precisely classify and sub-classify recurrent mood disorders like premenstrual dysphoric disorder (PMDD) and recurrent brief depressive disorder (RBD). We applied several complementary statistical methods to differentiate mood rating dynamics among women with PMDD, RBD, and normal controls (NC). We compared three subgroups of women: NC (n=8); PMDD (n=15); and RBD (n=9) on the basis of daily self-ratings of sadness, study lengths between 50 and 120 days. We analyzed mean levels; overall variability, SD; sequential irregularity, approximate entropy (ApEn); and a quantification of the extent of brief and staccato dynamics, denoted 'Spikiness'. For each of SD, irregularity (ApEn), and Spikiness, we showed highly significant subgroup differences, ANOVA0.001 for each statistic; additionally, many paired subgroup comparisons showed highly significant differences. In contrast, mean levels were indistinct among the subgroups. For SD, normal controls had much smaller levels than the other subgroups, with RBD intermediate. ApEn showed PMDD to be significantly more regular than the other subgroups. Spikiness showed NC and RBD data sets to be much more staccato than their PMDD counterparts, and appears to suitably characterize the defining feature of RBD dynamics. Compound criteria based on these statistical measures discriminated diagnostic subgroups with high sensitivity and specificity. Taken together, the statistical suite provides well-defined specifications of each subgroup. This can facilitate accurate diagnosis, and augment the prediction and evaluation of response to treatment. The statistical methodologies have broad and direct applicability to behavioral studies for many psychiatric disorders, and indeed to similar analyses of associated biological signals across multiple axes.

  19. Self-Rated Pubertal Development, Depressive Symptoms and Delinquency: Measurement Issues and Moderation by Gender and Maltreatment

    ERIC Educational Resources Information Center

    Negriff, Sonya; Fung, Michelle T.; Trickett, Penelope K.

    2008-01-01

    This cross-sectional study examined relationships between pubertal development, depressive symptoms and delinquency in a sample of 241 males and 213 females aged 9-13 years. Four objectives were set forth for this study: (1) to examine relationships between pubertal stage or timing and depressive symptoms and delinquency; (2) to compare continuous…

  20. Geomorphic consequences of volcanic eruptions in Alaska: A review

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.

    2015-10-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta-Katmai eruption, the 1989-1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed. A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment-water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite large

  1. Geomorphic Consequences of Volcanic Eruptions in Alaska: A Review

    USGS Publications Warehouse

    Waythomas, Christopher F.

    2015-01-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta–Katmai eruption, the 1989–1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed.A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment–water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite

  2. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Expedition Five crew members aboard the International Space Station (ISS) captured this overhead look at the smoke and ash regurgitated from the erupting volcano Mt. Etna on the island of Sicily, Italy in October 2002. Triggered by a series of earthquakes on October 27, 2002, this eruption was one of Etna's most vigorous in years. This image shows the ash plume curving out toward the horizon. The lighter-colored plumes down slope and north of the summit seen in this frame are produced by forest fires set by flowing lava. At an elevation of 10,990 feet (3,350 m), the summit of the Mt. Etna volcano, one of the most active and most studied volcanoes in the world, has been active for a half-million years and has erupted hundreds of times in recorded history.

  3. Characterize Eruptive Processes at Yucca Mountain, Nevada

    SciTech Connect

    G. Valentine

    2001-12-20

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain shapes.

  4. Magma chamber dynamics and Vesuvius eruption forecasting

    NASA Astrophysics Data System (ADS)

    Dobran, F.

    2003-04-01

    Magma is continuously or periodically refilling an active volcano and its eruption depends on the mechanical, fluid, thermal, and chemical aspects of the magma storage region and its surroundings. A cyclically loaded and unloaded system can fail from a weakness in the system or its surroundings, and the fluctuating stresses can produce system failures at stress levels that are considerably below the yield strength of the material. Magma in a fractured rock system within a volcano is unstable and propagates toward the surface with the rate depending on the state of the system defined by the inertia, gravity, friction, and permeability parameters of magma and its source region. Cyclic loading and unloading of magma from a reservoir caused by small- or medium-scale eruptions of Vesuvius can produce catastrophic plinian eruptions because of the structural failure of the system and the quiescent periods between these eruptions increase with time until the next eruption cycle which will be plinian or subplinian and will occur with a very high probability this century. Such a system behavior is predicted by a Global Volcanic Simulator of Vesuvius developed for simulating different eruption scenarios for the purpose of urban planning the territory, reducing the number of people residing too close to the cone of the volcano, and providing safety to those beyond about 5 km radius of the crater. The magma chamber model of the simulator employs a thermomechanical model that includes magma inflow and outflow from the chamber, heat and mass transfer between the chamber and its surroundings, and thermoelastoplastic deformation of the shell surrounding the magma source region. These magma chamber, magma ascent, and pyroclastic dispersion models and Vesuvius eruption forecasting are described in Dobran, F., VOLCANIC PROCESSES, Kluwer Academic/Plenum Publishers, 2001, 590 pp.

  5. Cause and risk of catastrophic eruptions in the Japanese Archipelago.

    PubMed

    Tatsumi, Yoshiyuki; Suzuki-Kamata, Keiko

    2014-01-01

    The Japanese Archipelago is characterized by active volcanism with variable eruption styles. The magnitude (M)-frequency relationships of catastrophic caldera-forming eruptions (M ≥ 7) are statistically different from those of smaller eruptions (M ≤ 5.7), suggesting that different mechanisms control these eruptions. We also find that volcanoes prone to catastrophic eruptions are located in regions of low crustal strain rate (<0.5 × 10(8)/y) and propose, as one possible mechanism, that the viscous silicic melts that cause such eruptions can be readily segregated from the partially molten lower crust and form a large magma reservoir in such a tectonic regime. Finally we show that there is a ∼1% probability of a catastrophic eruption in the next 100 years based on the eruption records for the last 120 ky. More than 110 million people live in an area at risk of being covered by tephra >20 cm thick, which would severely disrupt every day life, from such an eruption on Kyushu Island, SW Japan.

  6. Cause and risk of catastrophic eruptions in the Japanese Archipelago

    PubMed Central

    TATSUMI, Yoshiyuki; SUZUKI-KAMATA, Keiko

    2014-01-01

    The Japanese Archipelago is characterized by active volcanism with variable eruption styles. The magnitude (M)-frequency relationships of catastrophic caldera-forming eruptions (M ≥ 7) are statistically different from those of smaller eruptions (M ≤ 5.7), suggesting that different mechanisms control these eruptions. We also find that volcanoes prone to catastrophic eruptions are located in regions of low crustal strain rate (<0.5 × 108/y) and propose, as one possible mechanism, that the viscous silicic melts that cause such eruptions can be readily segregated from the partially molten lower crust and form a large magma reservoir in such a tectonic regime. Finally we show that there is a ∼1% probability of a catastrophic eruption in the next 100 years based on the eruption records for the last 120 ky. More than 110 million people live in an area at risk of being covered by tephra >20 cm thick, which would severely disrupt every day life, from such an eruption on Kyushu Island, SW Japan. PMID:25391319

  7. Cause and risk of catastrophic eruptions in the Japanese Archipelago.

    PubMed

    Tatsumi, Yoshiyuki; Suzuki-Kamata, Keiko

    2014-01-01

    The Japanese Archipelago is characterized by active volcanism with variable eruption styles. The magnitude (M)-frequency relationships of catastrophic caldera-forming eruptions (M ≥ 7) are statistically different from those of smaller eruptions (M ≤ 5.7), suggesting that different mechanisms control these eruptions. We also find that volcanoes prone to catastrophic eruptions are located in regions of low crustal strain rate (<0.5 × 10(8)/y) and propose, as one possible mechanism, that the viscous silicic melts that cause such eruptions can be readily segregated from the partially molten lower crust and form a large magma reservoir in such a tectonic regime. Finally we show that there is a ∼1% probability of a catastrophic eruption in the next 100 years based on the eruption records for the last 120 ky. More than 110 million people live in an area at risk of being covered by tephra >20 cm thick, which would severely disrupt every day life, from such an eruption on Kyushu Island, SW Japan. PMID:25391319

  8. The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives

    USGS Publications Warehouse

    Hildreth, Wes; Fierstein, Judy

    2012-01-01

    The explosive outburst at Novarupta (Alaska) in June 1912 was the 20th century's most voluminous volcanic eruption. Marking its centennial, we illustrate and document the complex eruptive sequence, which was long misattributed to nearby Mount Katmai, and how its deposits have provided key insights about volcanic and magmatic processes. It was one of the few historical eruptions to produce a collapsed caldera, voluminous high-silica rhyolite, wide compositional zonation (51-78 percent SiO2), banded pumice, welded tuff, and an aerosol/dust veil that depressed global temperature measurably. It emplaced a series of ash flows that filled what became the Valley of Ten Thousand Smokes, sustaining high-temperature metal-transporting fumaroles for a decade. Three explosive episodes spanned ~60 hours, depositing ~17 km3 of fallout and 11±2 km3 of ignimbrite, together representing ~13.5 km3 of zoned magma. No observers were nearby and no aircraft were in Alaska, and so the eruption narrative was assembled from scattered villages and ship reports. Because volcanology was in its infancy and the early investigations (1915-23) were conducted under arduous expeditionary conditions, many provocative misapprehensions attended reports based on those studies. Fieldwork at Katmai was not resumed until 1953, but, since then, global advances in physical volcanology and chemical petrology have gone hand in hand with studies of the 1912 deposits, clarifying the sequence of events and processes and turning the eruption into one of the best studied in the world. To provide perspective on this century-long evolution, we describe the geologic and geographic setting of the eruption - in a remote, sparsely inhabited wilderness; we review the cultural and scientific contexts at the time of the eruption and early expeditions; and we compile a chronology of the many Katmai investigations since 1912. Products of the eruption are described in detail, including eight layers of regionwide fallout

  9. a Solar Eruption Driven by Sunspot Rotation

    NASA Astrophysics Data System (ADS)

    CHEN, Y.; Ruan, G.

    2013-12-01

    We present an observational study of a major solar eruption associated with fast sunspot rotation. The event includes a sigmoidal filament eruption, a coronal mass ejection, and a GOES X2.1 flare from NOAA AR11283. The filament and some overlying coronal arcades were partially rooted in a sunspot, which rotated at an average rate of ˜10 degrees per hour during a period of 6 hours prior to the eruption. Along with the sunspot rotation, significant amounts of magnetic energy ~10^31 erg and helicity 10^41 Mx^2 were transported into the corona. In the 6-hour period, we also found an overall decrease (increase) of the mean photospheric horizontal field strength (magnetic field inclination angle) using the HMI data measured in the region along the polarity inversion line underneath the filament, and a gradual levitation of current density concentrations in the corona according to the NLFFF (NonLinear Force Free Field) extrapolation. These results indicate that the magnetic structure carrying the filament undergoes an overall gradual ascending motion before its final eruption, consistent in general with the observed filament dynamical evolution during the sunspot rotation. The study provides direct evidences of sunspot rotation as a major process twisting, energizing, and destabilizing the coronal filament-flux rope system leading to the eruption.

  10. Introduction to the 2012-2013 Tolbachik eruption special issue

    NASA Astrophysics Data System (ADS)

    Edwards, Benjamin R.; Belousov, Alexander; Belousova, Marina; Volynets, Anna

    2015-12-01

    The Tolbachik volcanic complex in central Kamchatka holds a special place in global volcanological studies. It is one of 4 areas of extensive historic volcanic activity in the northern part of the Central Kamchatka Depression (the others being Klyuchevskoy, Bezymianny, Shiveluch), and is part of the Klyuchevskoy volcanic group, which is one of the most active areas of volcanism on Earth. Tolbachik is especially well-known due largely to the massive 1975-1976 eruption that became known as the Great Tolbachik Fissure eruption (GTFE; Fedotov, 1983; Fedotov et al., 1984). This was one of the first eruptions in Russia to be predicted based on precursory seismic activity, based on M5 earthquakes approximately one week before the eruption started, and was intensively studied during its course by a large number of Russian scientists. A summary of those studies was published, first in Russian and then in English, and it became widely read for many reasons. One in particular is that the eruption was somewhat unusual for a subduction zone setting; although many subduction zone stratovolcanoes have associated basaltic tephra cone-lava fields, this was the first such Hawaiian-style eruption to be widely observed. After the end of the eruption in 1976, the complex showed no signs of activity until 27 November 2012, when increased seismic activity was registered by the Kamchatka Branch of the Russian Geophysical Survey and a red glow from the eruption site was first noticed through the snowstorm haze. This prompted them, and then the Kamchatka Volcanic Emergency Response Team (KVERT) to issue an alert that activity was coming from the south flank of Plosky Tolbachik volcano, the younger of two volcanic edifices (the older is Ostry Tolbachik) that together make up the bulk of the complex along with tephra cone-lava fields that lie along a NE-SW fissure zone that transects Plosky Tolbachik. The new eruption lasted for more than 250 days and, like the 1975-1976 eruption, was

  11. Preliminary findings of simultaneous 18F-FDG and 99mTc-HMPAO SPECT in patients with depressive disorders at rest: differential correlates with ratings of anxiety.

    PubMed

    Conca, A; Fritzsche, H; Peschina, W; König, P; Swoboda, E; Wiederin, H; Haas, C

    2000-02-28

    The assumption of a dynamic coupling between regional cerebral blood flow (rCBF) and cerebral glucose metabolic rates (rCMRGlu) has been challenged by simultaneous measurements of both. Through the use of a dual-headed gamma camera with a 511-keV collimator applying the double isotope 18F-FDG and 99mTc-HMPAO SPECT technique, the uptake rates of these isotopes can be semi-quantitatively evaluated. Sixteen depressed patients, diagnosed by ICD-10 criteria and assessed with the 17-item Hamilton Rating Scale for Depression (HRSD), were studied. Based on the severity of HRSD-rated anxiety (item 10: low=1-21; high=3-4), two eight-patient subgroups were formed and compared with 12 age- and handedness-matched healthy control subjects. As regions of interest, we selected areas implicated in the neuroanatomy of anxiety and depression: hippocampus (hippo), basal ganglia (BG) and gyri temporales superiores (G.t.s.). In the control subjects, a significant statistical coupling between rCBF and rCMRGlu was revealed by the Spearman correlation coefficient only in left hippo and left BG. Patients in the low-anxiety subgroup demonstrated a marked dynamic coupling bilaterally for the G.t.s., while patients in the high-anxiety subgroup showed a significant statistical correlation of rCBF and rCMRGlu only in the left G.t.s. These findings indicate that a dynamic coupling between blood flow and glucose metabolism exists only in distinct brain regions, and that the depressive illness has an uncoupling effect on this correlation in the left BG. Furthermore, our results suggest that the HRSD anxiety score might interact with the underlying depressive illness to influence the relationship of rCBF and rCMRGlu. PMID:10708925

  12. Eruptive parameters and dynamics of the April 2015 sub-Plinian eruptions of Calbuco volcano (southern Chile)

    NASA Astrophysics Data System (ADS)

    Castruccio, Angelo; Clavero, Jorge; Segura, Andrea; Samaniego, Pablo; Roche, Olivier; Le Pennec, Jean-Luc; Droguett, Bárbara

    2016-09-01

    We conducted geological and petrological analyses of the tephra fallout and pyroclastic density current (PDC) products of the 22-23 April 2015 Calbuco eruptions. The eruptive cycle consisted of two sub-Plinian phases that generated > 15 km height columns and PDCs that travelled up to 6 km from the vent. The erupted volume is estimated at 0.38 km3 (non-DRE), with approximately 90% corresponding to tephra fall deposits and the other 10% to PDC deposits. The erupted products are basaltic-andesite, 54-55 wt.% SiO2, with minor amounts of andesite (58 wt.% SiO2). Despite the uniform composition of the products, there are at least four types of textures in juvenile clasts, with different degrees of vesicularity and types and content of crystals. We propose that the eruption triggering mechanism was either exsolution of volatiles due to crystallization, or a small intrusion into the base of the magma chamber, without significant magma mixing or with a magma compositionally similar to that of the residing magma. In either case the triggering mechanism generated convection and sufficient overpressure to promote the first eruptive phase. The start of the eruption decompressed the chamber, promoting intense vesiculation of the remaining magma and an increase in eruption rate towards the end of the eruption.

  13. Can Rock Deformation Experiments Help us to Forecast Volcanic Eruptions?

    NASA Astrophysics Data System (ADS)

    Smith, R.; Kilburn, C. R.; Sammonds, P. R.

    2009-05-01

    Volcanic eruption forecasting models show that the strength and mechanical properties of volcanic rocks are a primary control on the behaviour of volcanic systems, especially during the approach to eruptions. The progressive failure of these rocks, recorded as sequences of small volcano tectonic earthquakes, can lead to the formation of new magma pathways, allowing eruptions to begin at volcanoes that have not erupted in hundreds of years. Rates and patterns of these small earthquakes, which are typically located within a few km of the volcano summit, are monitored at many volcanoes and used to forecast eruptions. Models of crack growth and interaction have been used to constrain expected patterns in accelerating earthquake rates before the first eruption after a long repose interval. These deterministic models rely on laboratory mechanical data from volcanic rocks tested under the temperature and pressure conditions expected within and beneath a volcanic edifice. Here, we present data from high temperature uniaxial and triaxial deformation of andesite and dacite at temperatures of up to 1000°C, and under confining pressures of up to 50 MPa. These are typical rock types for volcanoes likely to erupt violently after hundreds of years of repose, where these forecasting models have previously been applied. The conditions tested cover the full range of temperatures and pressures expected within the upper 2-3 km of volcanic systems. The eruption forecasting model, with new constraints from this laboratory data, is applied to sequences of VT earthquakes before eruptions and to sequences of acoustic emissions before laboratory sample failure. Both types of data showed accelerating trends within the limits defined in the model, whilst sequences of earthquakes and acoustic emissions not resulting in eruption or sample failure exhibited accelerations outside the model limits. These results support the scaling of laboratory data to field scale and the use of laboratory data

  14. Volcanic Eruptions and Climate

    NASA Technical Reports Server (NTRS)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  15. Eruption on Io

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This image, taken by NASA's Galileo spacecraft, shows a new blue-colored volcanic plume extending about 100 kilometers (about 60 miles) into space from Jupiter's moon Io (see inset at lower left). The blue color of the plume is consistent with the presence of sulfur dioxide gas and 'snow' condensing from the gas as the plume expands and cools. Galileo images have also shown that the Ra Patera plume glows in the dark, perhaps due to the fluorescence of sulfur and oxygen ions created by the breaking apart of sulfur dioxide molecules by energetic particles in the Jovian magnetosphere. The images at right show a comparison of changes seen near the volcano Ra Patera since the Voyager spacecraft flybys of 1979 (windows at right show Voyager image at top and Galileo image at bottom). This eruptive plume is an example of a new type of volcanic activity discovered during Voyager's flyby in 1979, believed to be geyser-like eruptions driven by sulfur dioxide or sulfur gas erupting and freezing in Io's extremely tenuous atmosphere. Volcanic eruptions on Earth cannot throw materials to such high altitudes. Ra Patera is the site of dramatic surface changes. An area around the volcano of about 40,000 square kilometers, area about the size of New Jersey, has been covered by new volcanic deposits. The image was taken in late June 28, 1996 from a distance of 972,000 kilometers (604,000 miles). The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

  16. Kimberlite ascent and eruption.

    PubMed

    Sparks, R S J; Brown, R J; Field, M; Gilbertson, M

    2007-12-13

    Wilson and Head model kimberlite ascent and eruption by considering the propagation of a volatile-rich dyke. Wilson and Head's model has features in common with Sparks et al., but it is inconsistent with geological observations and constraints on volatile solubility. Here we show that this may be due to erroneous physical assumptions.

  17. Kimberlite ascent and eruption.

    PubMed

    Sparks, R S J; Brown, R J; Field, M; Gilbertson, M

    2007-12-13

    Wilson and Head model kimberlite ascent and eruption by considering the propagation of a volatile-rich dyke. Wilson and Head's model has features in common with Sparks et al., but it is inconsistent with geological observations and constraints on volatile solubility. Here we show that this may be due to erroneous physical assumptions. PMID:18075522

  18. The Clarification of Depression and Social Support's Contribution to the Prediction of Antiretroviral Medication Adherence and the Rate of CD4 in People with HIV.

    PubMed

    Ebrahimzadeh, Zeinab; Goodarzi, Mohammad Ali; Joulaei, Hassan

    2016-01-01

    With the development of the antiretroviral therapy, the number of the people with HIV is increasing; therefore, identifying the factors affecting HIV is of great importance. This study aimed to investigate the relationship between the antiretroviral medication adherence and the rate of CD4 with depression and social support in the people with HIV. The research method was a descriptive study kind of correlation. The statistical population included all patients with HIV in Shiraz, of whom, 220 people who had referred to the Behavioral Diseases Consultation Center were selected using the available sampling method. Philips et al.'s Social Support Questionnaire, Beck's Depression Questionnaire II, and ACTG Medication Adherence Questionnaire were used as the research tools. Results were analyzed using the stepwise regression and stepwise hierarchical multiple regression. Regression analysis showed that social support and depression variables could predict totally 47% (P<0.001) of changes of medication adherence variable, and depression could predict only 2% (P<0.01) of rate variance of CD4. PMID:27157183

  19. The Clarification of Depression and Social Support’s Contribution to the Prediction of Antiretroviral Medication Adherence and the Rate of CD4 in People with HIV

    PubMed Central

    Ebrahimzadeh, Zeinab; Goodarzi, Mohammad Ali; Joulaei, Hassan

    2016-01-01

    With the development of the antiretroviral therapy, the number of the people with HIV is increasing; therefore, identifying the factors affecting HIV is of great importance. This study aimed to investigate the relationship between the antiretroviral medication adherence and the rate of CD4 with depression and social support in the people with HIV. The research method was a descriptive study kind of correlation. The statistical population included all patients with HIV in Shiraz, of whom, 220 people who had referred to the Behavioral Diseases Consultation Center were selected using the available sampling method. Philips et al.’s Social Support Questionnaire, Beck’s Depression Questionnaire II, and ACTG Medication Adherence Questionnaire were used as the research tools. Results were analyzed using the stepwise regression and stepwise hierarchical multiple regression. Regression analysis showed that social support and depression variables could predict totally 47% (P<0.001) of changes of medication adherence variable, and depression could predict only 2% (P<0.01) of rate variance of CD4. PMID:27157183

  20. Forecasting the Beginning, Middle, and End of Eruptions

    NASA Astrophysics Data System (ADS)

    Pallister, J. S.; McCausland, W. A.; Ogburn, S. E.; White, R. A.; Wright, H. M. N.

    2015-12-01

    Volcanic eruptions are triggered either by "bottom-up" processes such as magmatic intrusion and recharge or by "top-down" processes such as unloading by flank failure. Eruptions end when conduit pressure drops below lithostatic pressure because of depletion of magmatic gases or cessation of magmatic replenishment, or alternatively, as a consequence of plugging of the conduit by crystallization. Examples from the Volcano Disaster Assistance Program (VDAP) show that it is possible to forecast the beginning, changes during, and the end of eruptions using a combination of multi-parametric monitoring, geologic constraints and applicable information from global databases. Beginning: Magmatic intrusions can be detected from patterns of precursory seismicity, CO2 emissions, and inflation. The probability that a particular intrusive episode leads to eruption can be estimated from global data modified by the local history of past eruptions and by characteristic progressions in monitoring parameters. Middle: Increased probability of a more explosive phase during a long-lived dome-forming eruption may be forecast on the basis of high extrusion rates and recurrence of deep or distal VT earthquakes; both indicate more rapid magma ascent and increased gas pressure. Alternatively, increased seismicity coincident with a rapid decrease in gas emission and extrusion rate may signal conduit plugging, which can also lead to an explosive phase. End: The end of long-lived eruptions may be forecast using a combination of: 1) global data on duration of similar eruptions, 2) comparison of eruptive volumes to those of past eruptions, 3) projection of effusion rate trends to zero, 4) reversal of regional deflation to inflation and near-vent inflation to deflation, and 5) change in morphology or composition indicative of more viscous crystalline magma. We find that forecasting using the criteria such as described above is best conducted by multidisciplinary teams using probabilistic event

  1. Quiet-Region Filament Eruptions

    NASA Technical Reports Server (NTRS)

    Choudhary, Debi Prasad; Moore, Ronald L.

    2004-01-01

    We report characteristics of quiescent filament eruptions that did not produce coronal mass ejections (CMEs). It is known that there is a dichotomy of quiescent filament eruptions: those that produce CMEs and those that do not. We examined the quiescent filament eruptions, each of which was located far from disk center (greater than or equal to 0.7 R(sub Sun)) in diffuse remnant magnetic fields of decayed active regions, was well observed in Ha observations and Fe XII, and had good coronagraph coverage. We present the similarity and differences of two classes of filament eruptions. From their lack of CME production and the appearance of their eruptive motion in Fe XII movies, we conclude that the non-CME-producing filament eruptions are confined eruptions like the confined filament eruptions in active regions. We take the similarity of the confined and eruptive quiescent filament eruptions with their active-region counterparts to favor runaway tether-cutting connection for unleashing the magnetic explosion in all these eruptions.

  2. Spontaneous Eruption of Premolar Associated with a Dentigerous Cyst

    PubMed Central

    Luna, Anibal Henrique Barbosa

    2016-01-01

    Dentigerous cyst (DC) is the second most common odontogenic cyst with greater incidence in young patients. It presents as a unilocular, asymptomatic radiolucency involving the crown of an impacted tooth, commonly noticed in X-rays to investigate absence, wrong tooth position, or delay in the chronology of eruption. Decompression/marsupialization (D/M) is the most implemented treatment, especially when preserving the tooth involved is advised. The aim of this study is to discuss the DC characteristics that contribute to spontaneous eruption of premolars, by reporting the case of a conservative treatment of DC. This eruption depends on factors such as age, angulation of inclusion, rate of root formation, depth of inclusion, and eruption space. This paper reports the case of a 10-year-old patient with a radiolucent lesion diagnosed as DC involving element 35, which erupted as a result of treatment. The patient was observed during 1 year and 6 months. PMID:27313912

  3. Magnetic field restructuring associated with two successive solar eruptions

    SciTech Connect

    Wang, Rui; Liu, Ying D.; Yang, Zhongwei; Hu, Huidong

    2014-08-20

    We examine two successive flare eruptions (X5.4 and X1.3) on 2012 March 7 in the NOAA active region 11429 and investigate the magnetic field reconfiguration associated with the two eruptions. Using an advanced non-linear force-free field extrapolation method based on the SDO/HMI vector magnetograms, we obtain a stepwise decrease in the magnetic free energy during the eruptions, which is roughly 20%-30% of the energy of the pre-flare phase. We also calculate the magnetic helicity and suggest that the changes of the sign of the helicity injection rate might be associated with the eruptions. Through the investigation of the magnetic field evolution, we find that the appearance of the 'implosion' phenomenon has a strong relationship with the occurrence of the first X-class flare. Meanwhile, the magnetic field changes of the successive eruptions with implosion and without implosion were well observed.

  4. Depression - resources

    MedlinePlus

    Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good sources of information on depression : American Psychological Association -- www.apa.org/topics/depress/ ...

  5. Eruptive versus non-eruptive behaviour of large calderas: the example of Campi Flegrei caldera (southern Italy)

    NASA Astrophysics Data System (ADS)

    Carlino, Stefano; Somma, Renato

    2010-09-01

    Caldera eruptions are among the most hazardous of natural phenomena. Many calderas around the world are active and are characterised by recurrent uplift and subsidence periods due to the dynamics of their magma reservoirs. These periods of unrest are, in some cases, accompanied by eruptions. At Campi Flegrei caldera (CFc), which is an area characterised by very high volcanic risk, the recurrence of this behaviour has stimulated the study of the rock rheology around the magma chamber, in order to estimate the likelihood of an eruption. This study considers different scenarios of shallow crustal behaviour, taking into account the earlier models of CFc ground deformation and caldera eruptions, and including recent geophysical investigations of the area. A semi-quantitative evaluation of the different factors that lead to magma storage or to its eruption (such as magma chamber size, wall-rock viscosity, temperature, and regional tectonic strain rate) is reported here for elastic and viscoelastic conditions. Considering the large magmatic sources of the CFc ignimbrite eruptions (400-2,000 km3) and a wall-rock viscosity between 1018 and 1020 Pa s, the conditions for eruptive failure are difficult to attain. Smaller source dimensions (a few cubic kilometres) promote the condition for fracture (eruption) rather than for the flow of wall rock. We also analyse the influence of the regional extensional stress regime on magma storage and eruptions, and the thermal stress as a possible source of caldera uplift. The present study also emphasises the difficulty of distinguishing eruption and non-eruption scenarios at CFc, since an unambiguous model that accounts for the rock rheology, magma-source dimensions and locations and regional stress field influences is still lacking.

  6. Nyamuragira Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This true-color image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 28, 2002. Nyamuragira is situated roughly in the center of this scene, roughly 100 km south of Lake Edward and just north of Lake Kivu (which is mostly obscured by the haze from the erupting volcano and the numerous fires burning in the surrounding countryside). Due south of Lake Kivu is the long, narrow Lake Tanganyika running south and off the bottom center of this scene.

  7. The compounding effects of high pollen limitation, selfing rates and inbreeding depression leave a New Zealand tree with few viable offspring

    PubMed Central

    Van Etten, Megan L.; Tate, Jennifer A.; Anderson, Sandra H.; Kelly, Dave; Ladley, Jenny J.; Merrett, Merilyn F.; Peterson, Paul G.; Robertson, Alastair W.

    2015-01-01

    Background and Aims Interactions between species are especially sensitive to environmental changes. The interaction between plants and pollinators is of particular interest given the potential current global decline in pollinators. Reduced pollinator services can be compensated for in some plant species by self-pollination. However, if inbreeding depression is high, selfed progeny could die prior to reaching adulthood, leading to cryptic recruitment failure. Methods To examine this scenario, pollinator abundance, pollen limitation, selfing rates and inbreeding depression were examined in 12 populations of varying disturbance levels in Sophora microphylla (Fabaceae), an endemic New Zealand tree species. Key Results High pollen limitation was found in all populations (average of 58 % reduction in seed production, nine populations), together with high selfing rates (61 % of offspring selfed, six populations) and high inbreeding depression (selfed offspring 86 % less fit, six populations). Pollen limitation was associated with lower visitation rates by the two endemic bird pollinators. Conclusions The results suggest that for these populations, over half of the seeds produced are genetically doomed. This reduction in the fitness of progeny due to reduced pollinator service is probably important to population dynamics of other New Zealand species. More broadly, the results suggest that measures of seed production or seedling densities may be a gross overestimate of the effective offspring production. This could lead to cryptic recruitment failure, i.e. a decline in successful reproduction despite high progeny production. Given the global extent of pollinator declines, cryptic recruitment failure may be widespread. PMID:26229065

  8. Disparate rates of new-onset depression during the menopausal transition in 2 community-based populations: real, or really wrong?

    PubMed

    Harlow, Bernard L; MacLehose, Richard F; Smolenski, Derek J; Soares, Claudio N; Otto, Michael W; Joffe, Hadine; Cohen, Lee S

    2013-05-15

    This study took place in eastern Massachusetts and included respondents from the Harvard Study of Moods and Cycles Cohort 1, enrolled between 1995 and 1997, and the Harvard Study of Moods and Cycles Cohort 2, enrolled between 2005 and 2009. In prospectively assessing rates of new-onset depression in 2 populations of late-reproductive-aged women with no Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) lifetime history of depression, we were surprised to find far lower rates of depression in the population with greater racial diversity and lower socioeconomic status, contrary to what had been reported in the scientific literature. To better understand why these disparate results occurred, we assessed confounding and outcome misclassification as potential explanations for the discrepancy. After determining that these were unlikely explanations for the findings, we explored 2 potential sources of selection bias: one induced by self-referral of healthy participants into the study and the other induced by the design of the study itself. We concluded that both types of selection bias were likely to have occurred in this study and could account for the observed difference in rates.

  9. 2-D Numerical Simulation of Eruption Clouds : Effects of Turbulent Mixing between Eruption Cloud and Air

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; KOYAGUCHI, T.; OGAWA, M.; Hachisu, I.

    2001-05-01

    Mixing of eruption cloud and air is one of the most important processes for eruption cloud dynamics. The critical condition of eruption types (eruption column or pyroclastic flow) depends on efficiency of mixing of eruption cloud and the ambient air. However, in most of the previous models (e.g., Sparks,1986; Woods, 1988), the rate of mixing between cloud and air is taken into account by introducing empirical parameters such as entrainment coefficient or turbulent diffusion coefficient. We developed a numerical model of 2-D (axisymmetrical) eruption columns in order to simulate the turbulent mixing between eruption column and air. We calculated the motion of an eruption column from a circular vent on the flat surface of the earth. Supposing that relative velocity of gas and ash particles is sufficiently small, we can treat eruption cloud as a single gas. Equation of state (EOS) for the mixture of the magmatic component (i.e. volcanic gas plus pyroclasts) and air can be expressed by EOS for an ideal gas, because volume fraction of the gas phase is very large. The density change as a function of mixing ratio between air and the magmatic component has a strong non-linear feature, because the density of the mixture drastically decreases as entrained air expands by heating. This non-linear feature can be reproduced by changing the gas constant and the ratio of specific heat in EOS for ideal gases; the molecular weight increases and the ratio of specific heat approaches 1 as the magmatic component increases. It is assumed that the dynamics of eruption column follows the Euler equation, so that no viscous effect except for the numerical viscosity is taken into account. Roe scheme (a general TVD scheme for compressible flow) is used in order to simulate the generation of shock waves inside and around the eruption column. The results show that many vortexes are generated around the boundary between eruption cloud and air, which results in violent mixing. When the size of

  10. Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

    NASA Astrophysics Data System (ADS)

    Laakso, A.; Kokkola, H.; Partanen, A.-I.; Niemeier, U.; Timmreck, C.; Lehtinen, K. E. J.; Hakkarainen, H.; Korhonen, H.

    2016-01-01

    Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an Earth system model to study the radiative and climate changes occurring after an erupting volcano during solar radiation management (SRM). According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. In the former case, the peak burden of the additional stratospheric sulfate as well as changes in global mean precipitation are fairly similar regardless of whether the eruption takes place in a SRM or non-SRM world. However, the maximum increase in the global mean radiative forcing caused by the eruption is approximately 21 % lower compared to a case when the eruption occurs in an unperturbed atmosphere. In addition, the recovery of the stratospheric sulfur burden and radiative forcing is significantly faster after the eruption, because the eruption during the SRM leads to a smaller number and larger sulfate particles compared to the eruption in a non-SRM world. On the other hand, if SRM is suspended immediately after the eruption, the peak increase in global forcing caused by the eruption is about 32 % lower compared to a corresponding eruption into a clean background atmosphere. In this simulation, only about one-third of the global ensemble-mean cooling occurs after the eruption, compared to that occurring after an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal is seen only for the 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of global precipitation rate, we obtain a 36 % smaller decrease in the

  11. The Variable Climate Impact of Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Graf, H.

    2011-12-01

    The main effect of big volcanic eruptions in the climate system is due to their efficient transport of condensable gases and their precursors into the stratosphere. There the formation of aerosols leads to effects on atmospheric radiation transfer inducing a reduction of incoming solar radiation by reflection (i.e. cooling of the Earth surface) and absorption of near infrared radiation (i.e. heating) in the aerosol laden layers. In the talk processes determining the climate effect of an eruption will be illustrated by examples, mainly from numerical modelling. The amount of gases released from a magma during an eruption and the efficiency of their transport into very high altitudes depends on the geological setting (magma type) and eruption style. While mid-sized eruption plumes of Plinian style quickly can develop buoyancy by entrainment of ambient air, very large eruptions with high magma flux rates often tend to collapsing plumes and co-ignimbrite style. These cover much bigger areas and are less efficient in entraining ambient air. Vertical transport in these plumes is chaotic and less efficient, leading to lower neutral buoyancy height and less gas and particles reaching high stratospheric altitudes. Explosive energy and amount of released condensable gases are not the only determinants for the climatic effect of an eruption. The effect on shortwave radiation is not linear with the amount of aerosols formed since according to the Lambert-Beer Law atmospheric optical depth reaches a saturation limit with increased absorber concentration. In addition, if more condensable gas is available for aerosol growth, particles become larger and this affects their optical properties to less reflection and more absorption. Larger particles settle out faster, thus reducing the life time of the aerosol disturbance. Especially for big tropical eruptions the strong heating of the stratosphere in low latitudes leads to changes in atmospheric wave propagation by strengthened

  12. Magma movements and Iceland's next eruptions (Invited)

    NASA Astrophysics Data System (ADS)

    Sigmundsson, F.; Ofeigsson, B.; Hreinsdottir, S.; Hensch, M.; Gudmundsson, G.; Vogfjord, K. S.; Roberts, M. J.; Geirsson, H.; La Femina, P. C.; Hooper, A. J.; Sturkell, E. C.; Einarsson, P.; Gudmundsson, M. T.; Brandsdottir, B.; Loughlin, S. C.; Team, F.

    2013-12-01

    Iceland, created by hotspot-ridge interaction, is characterized by higher magmatic input and more complicated plate boundary structure than other parts of the Mid-Atlantic rift system. It has 30+ volcanic systems, where 20 confirmed eruptions have occurred in the last 40 years, the most recent at Eyjafjallajökull in 2010 and Grimsvotn in 2011. Likely candidates for the next eruption include the four most active volcanoes in Iceland (Hekla, Katla, Grimsvotn, and Bardarbunga) and other areas of volcanic unrest (Askja region, the Krisuvik area). Present volcano monitoring and research, including the FUTUREVOLC project, aims at providing warnings of impending eruptions and their character. Earthquake monitoring and deformation studies have hereto provided the most relevant information. Hekla continuously accumulates magma at a rate of about 0.003-0.02 km3/yr, according to GPS and InSAR studies, in a magma chamber placed below 14 km depth. A sequence of M0.4-1 earthquakes early this year stands out from otherwise mostly aseismic character of Hekla during repose periods. The Hekla magma chamber does not fail at a constant amount of magma volume, rather a clear pattern is observed with eruption size scaling with the length of the preceding period of dormancy. The ice capped Katla volcano shows unusual annual deformation pattern, seismic activity, and hydrological variations depending on time of year, presumably related to ice load and water pressure variations. It may be in a critical stage and renewed inflow of magma may quickly move the volcano towards failure. Bardarbunga had major earthquake and magma transfer activity in 1996, and has been the site of deep low-frequency earthquakes. Grímsvötn volcano is the only volcano with a shallow magma chamber with ongoing confirmed recharging, and failure criteria closest to 'expected'. A large eruption occurred in 2011 compared to much smaller eruption in 2004. However, the amount of erupted magma did not scale with the

  13. The 1984 Mauna Loa eruption and planetary geolgoy

    NASA Technical Reports Server (NTRS)

    Moore, Henry J.

    1987-01-01

    In planetary geology, lava flows on the Moon and Mars are commonly treated as relatively simple systems. Some of the complexities of actual lava flows are illustrated using the main flow system of the 1984 Mauna Loa eruption. The outline, brief narrative, and results given are based on a number of sources. The implications of the results to planetary geology are clear. Volume flow rates during an eruption depend, in part, on the volatile content of the lava. These differ from the volume flow rates calculated from post eruption flow dimensions and the duration of the eruption and from those using models that assume a constant density. Mass flow rates might be more appropriate because the masses of volatiles in lavas are usually small, but variable and sometimes unknown densities impose severe restrictions on mass estimates.

  14. Novel Interpretation for Shift Between Eruptive Styles in Some Volcanoes

    NASA Astrophysics Data System (ADS)

    Polacci, Margherita; Rosi, Mauro; Landi, Patrizia; Di Muro, Andrea; Papale, Paolo

    2005-09-01

    The transition from effusive, low mass flow rate to explosive, high mass flow rate eruptive behavior is a common aspect of the activity of calc- alkaline volcanoes. However, the process driving the shift between the two eruptive styles is at present debatable and represents a topical theme in the volcanological literature. The main challenge is to understand the mechanism that allows a high mass flow rate when eruptions of highly porphyritic (>=40 vol % crystals) and viscous magmas (>106 Pas, pascal second) occur. In this article, volcanological, compositional, and textural observations are used to demonstrate that viscous dissipation, a process that develops heating within flowing magma in a boundary layer near the conduit walls due to friction, is responsible for the long-lasting, sustained explosive phases of this eruption type, as well as for the transition from effusive to explosive behavior.

  15. Models of volcanic eruption hazards

    SciTech Connect

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  16. Modeling Explosive Eruptions at Kīlauea, Hawai'i

    NASA Astrophysics Data System (ADS)

    Gonnermann, H. M.; Ferguson, D. J.; Blaser, A. P.; Houghton, B. F.; Plank, T. A.; Hauri, E. H.; Swanson, D. A.

    2014-12-01

    We have modeled eruptive magma ascent during two explosive eruptions of Kīlauea volcano, Hawai'i. They are the Hawaiian style Kīlauea Iki eruption, 1959, and the subplinian Keanakāko'i eruption, 1650 CE. We have modeled combined magma ascent in the volcanic conduit and exsolution of H2O and CO2 from the erupting magma. To better assess the relative roles of conduit processes and magma chamber, we also coupled conduit flow and magma chamber through mass balance and pressure. We predict magma discharge rates, superficial gas velocities, H2O and CO2 concentrations of the melt, magma chamber pressure, surface deformation, and height of the volcanic jet. Models are in part constrained by H2O and CO2 measured in olivine-hosted melt inclusions and by decompression rates recorded in melt embayment diffusion profiles. We present a parametric analysis, indicating that the pressure within the chamber that fed the subplinian Keanakāko'i eruption was significantly higher than lithostatic pressure. In contrast, chamber pressure for the Hawaiian Kīlauea Iki eruption was close to lithostatic. In both cases the superficial gas velocity, which affects the geometrical distribution of gas-liquid mixtures during upward flow in conduits, may have exceeded values at which bubble coalescence did not affect the flow.

  17. Role of magma-water interaction in very large explosive eruptions

    SciTech Connect

    Valentine, G.A.

    1993-11-01

    An important class of explosive eruptions, involving large-scale magma-water interaction during the discharge of hundreds to thousands of cubic kilometers of magma, is discussed. Geologic evidence for such eruptions is summarized. Case studies from New Zealand, Australia, England, and the western United States are described, focusing on inferred eruption dynamics. Several critical problems that need theoretical and experimental research are identified. These include rates at which water can flow into a volcanic vent or plumbing system, entrainment of water by explosive eruptions through lakes and seas, effects of magma properties and gas bubbles on magma-water interaction, and hazards associated with the eruptions.

  18. Predicting Major Solar Eruptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    , whether an active region that produces a flare will also produce a CME. Bobra and Ilonidis then use a feature-selection algorithm to try to understand which features distinguish between flaring regions that dont produce a CME and those that do.Predictors of CMEsThe authors reach several interesting conclusions:Under the right conditions, their algorithm is able to predict whether an active region with a given set of features will produce a CME as well as a flare with a fairly high rate of success.None of the 18 features they tested are good predictors in isolation: its necessary to look at a combination of at least 6 features to have success predicting whether a flare will be accompanied by a CME.The features that are the best predictors are all intensive features ones that stay the same independent of the active regions size. Extensive features ones that change as the active region grows or shrinks are less successful predictors.Only the magnetic field properties of the photosphere were considered, so a logical next step is to extend this study to consider properties of the solar corona above active regions as well. In the meantime, these are interesting first results that may well help us better predict these major solar eruptions.BonusCheck out this video for a great description from NASA of the difference between solar flares and CMEs (as well as some awesome observations of both).CitationM. G. Bobra and S. Ilonidis 2016 ApJ 821 127. doi:10.3847/0004-637X/821/2/127

  19. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier.

  20. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

    Ohtawa, Yumi; Ichinohe, Saori; Kimura, Eri; Hashimoto, Sadamitsu

    2013-01-01

    Odontomas, benign tumors that develop in the jaw, rarely erupt into the oral cavity. We report an erupted odontoma which delayed eruption of the first molar. The patient was a 10-year-old Japanese girl who came to our hospital due to delayed eruption of the right maxillary first molar. All the deciduous teeth had been shed. The second premolar on the right side had erupted, but not the first molar. Slight inflammation of the alveolar mucosa around the first molar had exposed a tooth-like, hard tissue. Panoramic radiography revealed a radiopaque mass indicating a lesion approximately 1 cm in diameter. The border of the image was clear, and part of the mass was situated close to the occlusal surface of the first molar. The root of the maxillary right first molar was only half-developed. A clinical diagnosis of odontoma was made. The odontoma was subsequently extracted, allowing the crown of the first molar to erupt almost 5 months later. The dental germ of the permanent tooth had been displaced by the odontoma. However, after the odontoma had been extracted, the permanent tooth was still able to erupt spontaneously, as eruptive force still remained. When the eruption of a tooth is significantly delayed, we believe that it is necessary to examine the area radiographically. If there is any radiographic evidence of a physical obstruction that might delay eruption, that obstruction should be removed before any problems can arise. Regular dental checkups at schools might improve our ability to detect evidence of delayed eruption earlier. PMID:24521551

  1. Quantifying the condition of eruption column collapse during explosive volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Koyaguchi, Takehiro; Suzuki, Yujiro

    2016-04-01

    During an explosive eruption, a mixture of pyroclasts and volcanic gas forms a buoyant eruption column or a pyroclastic flow. Generation of a pyroclastic flow caused by eruption column collapse is one of the most hazardous phenomena during explosive volcanic eruptions. The quantification of column collapse condition (CCC) is, therefore, highly desired for volcanic hazard assessment. Previously the CCC was roughly predicted by a simple relationship between magma discharge rate and water content (e.g., Carazzo et al., 2008). When a crater is present above the conduit, because of decompression/compression process inside/above the crater, the CCC based on this relationship can be strongly modified (Woods and Bower, 1995; Koyaguchi et al., 2010); however, the effects of the crater on CCC has not been fully understood in a quantitative fashion. Here, we have derived a semi-analytical expression of CCC, in which the effects of the crater is taken into account. The CCC depends on magma properties, crater shape (radius, depth and opening angle) as well as the flow rate at the base of crater. Our semi-analytical CCC expresses all these dependencies by a single surface in a parameter space of the dimensionless magma discharge rate, the dimensionless magma flow rate (per unit area) and the ratio of the cross-sectional areas at the top and the base of crater. We have performed a systematic parameter study of three-dimensional (3D) numerical simulations of eruption column dynamics to confirm the semi-analytical CCC. The results of the 3D simulations are consistent with the semi-analytical CCC, while they show some additional fluid dynamical features in the transitional state (e.g., partial column collapse). Because the CCC depends on such many parameters, the scenario towards the generation of pyroclastic flow during explosive eruptions is considered to be diverse. Nevertheless, our semi-analytical CCC together with the existing semi-analytical solution for the 1D conduit flow

  2. Using Infrasound and Machine Learning for Monitoring Plinian Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Ham, F. M.; Iyengar, I.; Hambebo, B. M.; Garces, M. A.; Deaton, J.; Perttu, A.; Williams, B.

    2012-12-01

    Large plinian volcanic eruptions can inject a substantial amount of volcanic gas and ash into the stratosphere. This can present a severe hazard to commercial air traffic. A hazardous Icelandic volcanic ash-eruption was reported on April 14, 2010. This resulted in London's aviation authority to issue an alert that an ash plume was moving from an eruption in Iceland towards northwestern Europe. This eruption resulted in the closure of large areas of European airspace. Large plinian volcanic eruptions radiate infrasonic signals that can be detected by a global infrasound array network. To reduce potential hazards for commercial aviation from volcanic ash, these infrasound sensor arrays have been used to detect infrasonic signals released by sustained volcanic eruptions that can inject ash into the stratosphere at aircraft's cruising altitudes, typically in the order of 10km. A system that is capable of near, real-time eruption detection and discrimination of plinian eruptions from other natural phenomena that can produce infrasound with overlapping spectral content (0.01 to 0.1 Hz) is highly desirable to provide ash-monitoring for commercial aviation. In the initial study, cepstral features were extracted from plinian volcanic eruptions and mountain associated wave infrasound signals. These feature vectors were then used to train and test a two-module neural network classifier (radial basis function neural networks were used for each module). One module is dedicated to classifying plinian volcanic eruptions, the other mountain associated waves. Using an independent validation dataset, the classifier's correct classification rate was 91.5%. Then a different two-module neural network classifier was designed to discriminate between plinian volcanic eruptions and a collection of infrasound signals that are not-of-interest but have spectral content that overlaps with the volcano signals. One module is again dedicated to classifying plinian volcanic eruptions, however, in

  3. Decompression experiments identify kinetic controls on explosive silicic eruptions

    USGS Publications Warehouse

    Mangan, M.T.; Sisson, T.W.; Hankins, W.B.

    2004-01-01

    Eruption intensity is largely controlled by decompression-induced release of water-rich gas dissolved in magma. It is not simply the amount of gas that dictates how forcefully magma is propelled upwards during an eruption, but also the rate of degassing, which is partly a function of the supersaturation pressure (??Pcritical) triggering gas bubble nucleation. High temperature and pressure decompression experiments using rhyolite and dacite melt reveal compositionally-dependent differences in the ??Pcritical of degassing that may explain why rhyolites have fueled some of the most explosive eruptions on record.

  4. Aspects of historical eruptive activity and volcanic unrest at Mt. Tongariro, New Zealand: 1846-2013

    NASA Astrophysics Data System (ADS)

    Scott, Bradley J.; Potter, Sally H.

    2014-10-01

    The 6 August and 21 November 2012 eruptions from Upper Te Maari crater have heightened interest in past activity at Mt. Tongariro, New Zealand. Risks caused by volcanic hazards are increasingly being quantified by using probability estimates through expert elicitation, partly based on the frequency of past eruptions. To maximise the accuracy of these risk values at Mt. Tongariro, a historical eruption catalogue is required. This paper presents the findings of a detailed historical chronology of unrest and eruptions at Mt. Tongariro between 1846 AD and 2013 AD. It builds on the findings of previous researchers, highlighting that volcanic eruptions and unrest have occurred frequently from this volcano. Eruptions are now thought to have occurred at Mt. Tongariro in 1869, 1892, 1896-97, 1899, 1926, 1927, 1934 and 2012. Eruptions also potentially occurred in 1846, 1855, 1886, and 1928, in addition to frequent eruptions from neighbouring Mt. Ngauruhoe. The number of recognised eruptions during the 1896-97 episode has increased to 18, and the Red Crater area has been found to be more active than previously appreciated. Multiple episodes of unrest not resulting in eruptions have also been identified. New eruption recurrence rates are derived from this catalogue, with the baseline probability of the onset of an eruption episode calculated to be 0.07 per year (if 1896-97 and 2012 are considered as one episode each, and all others separately), and the maximum eruption rate within an eruption episode is 18 per year. These new data contribute towards risk assessments for future eruptions at Mt. Tongariro.

  5. Vesiculation of basaltic magma during eruption

    USGS Publications Warehouse

    Mangan, M.T.; Cashman, K.V.; Newman, S.

    1993-01-01

    Vesicle size distributions in vent lavas from the Pu'u "O'o-Kupaianaha eruption of Kilauea volcano are used to estimate nucleation and growth rates of H2O-rich gas bubbles in basaltic magma nearing the earth's surface (???120 m depth). By using well-constrained estimates for the depth of volatile exsolution and magma ascent rate, nucleation rates of 35.9 events.cm-3.s-1 and growth rates of 3.2 ?? 10-4cm/s are determined directly from size-distribution data. The results are consistent with diffusion-controlled growth as predicted by a parabolic growth law. -from Authors

  6. Will Teide erupt again?

    NASA Astrophysics Data System (ADS)

    Marti, Joan; Geyer, Adelina

    2016-04-01

    The quantification of hazard in volcanic systems characterised by long repose period is difficult because the lack of knowledge of the past volcanic history and also because in many cases volcanism is not perceived as a potential problem, being only regarded as an attraction for tourism or a source of economic benefit, thus hiding the need to conduct hazard assessment. Teide, in the island of Tenerife (Canary Islands), is not an exception to this general rule and, despite being one of the largest composite volcanoes in the World, it is generally considered as a non-active volcano by population, visitors and even by some scientists. However, geological and geophysical evidence, including a large diversity of monitoring signals recorded during last decades, as well as a simple comparison with similar volcanoes that have erupted in recent times after hundreds or even thousands of years of quiescence, recommend to consider Teide as an active volcano and to take the necessary precaution in an island with nearly one million of permanent inhabitants and nearly 5 millions of visitors per year. What is the potential of Teide to erupt again? is the question that relies behind the fact of considering it as active, and that needs to be answered first. Based on the current volcanological, petrological and geophysical knowledge We propose a conceptual model on the magma recharge mechanisms, structure of the plumbing system, and eruption triggers and dynamics of Teide volcano that helps to understand its behaviour and to anticipate future activity. Ramón y Cajal contract (RYC-2012-11024)

  7. Nyamuragira Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyamuragira volcano erupted on July 26, 2002, spewing lava high into the air along with a large plume of steam, ash, and sulfur dioxide. The 3,053-meter (10,013-foot) volcano is located in eastern Congo, very near that country's border with Rwanda. Nyamuragira is the smaller, more violent sibling of Nyiragongo volcano, which devastated the town of Goma with its massive eruption in January 2002. Nyamuragira is situated just 40 km (24 miles) northeast of Goma. This pair of images was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on July 26. The image on the left shows the scene in true color. The small purple box in the upper righthand corner marks the location of Nyamuragira's hot summit. The false-color image on the right shows the plume from the volcano streaming southwestward. This image was made using MODIS' channels sensitive at wavelengths from 8.5 to 11 microns. Red pixels indicate high concentrations of sulphur dioxide. Image courtesy Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison

  8. ON THE ERUPTION OF CORONAL FLUX ROPES

    SciTech Connect

    Fan, Y.

    2010-08-10

    We present three-dimensional MHD simulations of the evolution of the magnetic field in the corona where the emergence of a twisted magnetic flux tube is driven at the lower boundary into a pre-existing coronal potential arcade field. Through a sequence of simulations in which we vary the amount of twisted flux transported into the corona before the emergence is stopped, we investigate the conditions that lead to a dynamic eruption of the resulting coronal flux rope. It is found that the critical condition for the onset of eruption is for the center of the flux rope to reach a critical height at which the corresponding potential field declines with height at a sufficiently steep rate, consistent with the onset of the torus instability of the flux rope. In some cases, immediately after the emergence is stopped, the coronal flux rope first settles into a quasi-static rise with an underlying sigmoid-shaped current layer developing. Preferential heating of field lines going through this current layer may give rise to the observed quiescent X-ray sigmoid loops before eruption. Reconnections in the current layer during the initial quasi-static stage is found to add detached flux to the coronal flux rope, allowing it to rise quasi-statically to the critical height and dynamic eruption of the flux rope then ensues. By identifying field lines whose tops are in the most intense part of the current layer during the eruption, we deduce the evolution and morphology of the post-flare X-ray loops and the flare ribbons at their footpoints.

  9. Drug Rash (Unclassified Drug Eruption) in Children

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Drug Eruption, Unclassified (Pediatric) A parent's guide to condition ... lesions coming together into larger lesions typical of drug rashes (eruptions). Overview A drug eruption, also known ...

  10. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1989-01-01

    The physical processes generating nova eruptions are reviewed, along with the effects on nova eruptions of binary-system parameters such as the chemical composition or mass of the white dwarf and the mass accretion rate. Also considered are the possible metamorphosis from dwarf to classical novae and back again, X-ray and gamma-ray emission from novae, and the characteristics and distributions of novae in globular clusters and extragalactic systems. Limitations of the thermonuclear runaway model are discussed. 159 references.

  11. The physics of large eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust

    2015-04-01

    Based on eruptive volumes, eruptions can be classified as follows: small if the volumes are from less than 0.001 km3 to 0.1 km3, moderate if the volumes are from 0.1 to 10 km3, and large if the volumes are from 10 km3 to 1000 km3 or larger. The largest known explosive and effusive eruptions have eruptive volumes of 4000-5000 km3. The physics of small to moderate eruptions is reasonably well understood. For a typical mafic magma chamber in a crust that behaves as elastic, about 0.1% of the magma leaves the chamber (erupted and injected as a dyke) during rupture and eruption. Similarly, for a typical felsic magma chamber, the eruptive/injected volume during rupture and eruption is about 4%. To provide small to moderate eruptions, chamber volumes of the order of several tens to several hundred cubic kilometres would be needed. Shallow crustal chambers of these sizes are common, and deep-crustal and upper-mantle reservoirs of thousands of cubic kilometres exist. Thus, elastic and poro-elastic chambers of typical volumes can account for small to moderate eruptive volumes. When the eruptions become large, with volumes of tens or hundreds of cubic kilometres or more, an ordinary poro-elastic mechanism can no longer explain the eruptive volumes. The required sizes of the magma chambers and reservoirs to explain such volumes are simply too large to be plausible. Here I propose that the mechanics of large eruptions is fundamentally different from that of small to moderate eruptions. More specifically, I suggest that all large eruptions derive their magmas from chambers and reservoirs whose total cavity-volumes are mechanically reduced very much during the eruption. There are two mechanisms by which chamber/reservoir cavity-volumes can be reduced rapidly so as to squeeze out much of, or all, their magmas. One is piston-like caldera collapse. The other is graben subsidence. During large slip on the ring-faults/graben-faults the associated chamber/reservoir shrinks in volume

  12. The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives

    USGS Publications Warehouse

    Hildreth, Wes; Fierstein, Judy

    2012-01-01

    The explosive outburst at Novarupta (Alaska) in June 1912 was the 20th century's most voluminous volcanic eruption. Marking its centennial, we illustrate and document the complex eruptive sequence, which was long misattributed to nearby Mount Katmai, and how its deposits have provided key insights about volcanic and magmatic processes. It was one of the few historical eruptions to produce a collapsed caldera, voluminous high-silica rhyolite, wide compositional zonation (51-78 percent SiO2), banded pumice, welded tuff, and an aerosol/dust veil that depressed global temperature measurably. It emplaced a series of ash flows that filled what became the Valley of Ten Thousand Smokes, sustaining high-temperature metal-transporting fumaroles for a decade. Three explosive episodes spanned ~60 hours, depositing ~17 km3 of fallout and 11±2 km3 of ignimbrite, together representing ~13.5 km3 of zoned magma. No observers were nearby and no aircraft were in Alaska, and so the eruption narrative was assembled from scattered villages and ship reports. Because volcanology was in its infancy and the early investigations (1915-23) were conducted under arduous expeditionary conditions, many provocative misapprehensions attended reports based on those studies. Fieldwork at Katmai was not resumed until 1953, but, since then, global advances in physical volcanology and chemical petrology have gone hand in hand with studies of the 1912 deposits, clarifying the sequence of events and processes and turning the eruption into one of the best studied in the world. To provide perspective on this century-long evolution, we describe the geologic and geographic setting of the eruption - in a remote, sparsely inhabited wilderness; we review the cultural and scientific contexts at the time of the eruption and early expeditions; and we compile a chronology of the many Katmai investigations since 1912. Products of the eruption are described in detail, including eight layers of regionwide fallout

  13. Forecasting volcanic eruptions: the narrow margin between eruption and intrusion

    NASA Astrophysics Data System (ADS)

    Steele, Alexander; Kilburn, Christopher; Wall, Richard; Charlton, Danielle

    2016-04-01

    Volcano-tectonic (VT) seismicity is one of the primary geophysical signals for monitoring volcanic unrest. It measures the brittle response of the crust to changes in stress and provides a natural proxy for gauging the stability of a pressurizing body of magma. Here we apply a new model of crustal extension to observations from the 2015 unrest of Cotopaxi, in Ecuador. The model agrees well with field data and is consistent with accelerating unrest during the pressurization and rupture of a vertically-extended magma source within the volcanic edifice. At andesitic-dacitic stratovolcanoes in subduction zones, unrest after long repose is often characterised by increases in VT event rate that change from an exponential to hyperbolic trend with time. This sequence was observed when renewed unrest was detected in April 2015 at Cotopaxi, following at least 73 years of repose. After about 80 days of elevated seismicity at an approximately steady rate, the numbers of VT events increased exponentially with time for c. 80 days, before increasing for c. 15 days along a faster, hyperbolic trend. Both trends were characterised by the same value of 2 for the ratio of maximum applied stress SF to tensile strength of the crust σT, consistent with the pressurization of an approximately vertical, cylindrical magma body. The hyperbolic trend indicated a potential rupture on 25 September. Rupture appears to have occurred on 21-22 September, when the VT rate rapidly decreased. However, no major eruption accompanied the change, suggesting that a near-surface intrusion occurred instead. Although the quantitative VT trends were consistent with the rupture of a magmatic body, they could not on their own distinguish between an eruptive or intrusive outcome. An outstanding goal remains to identify additional precursory characteristics for quantifying the probability that magma will reach the surface after escaping from a ruptured parent body. Data for this analysis were kindly made available

  14. Brooding rumination and heart rate variability in women at high and low risk for depression: group differences and moderation by COMT genotype.

    PubMed

    Woody, Mary L; McGeary, John E; Gibb, Brandon E

    2014-02-01

    There is growing evidence that rumination, perhaps specifically brooding rumination, is a core feature of depression and that it contributes to the development and maintenance of the disorder. A separate line of research has highlighted the role played by heart rate variability (HRV). Both brooding rumination and HRV appear to be driven by disruption in the same neural circuit, heightened amygdala reactivity combined with decreased prefrontal control, and both are highlighted in different units of analysis as reflecting the Research Domain Criteria (RDoC) construct of Loss. However, little is known about the relation among these variables. In the current study, we predicted that higher levels of brooding rumination would be associated with lower levels of HRV and that women at high risk for future depression (i.e., those with a history of past major depressive disorder [MDD]) would exhibit higher levels of brooding and lower levels of HRV. We also examined genetic influences on the variables in this model. We predicted that COMT Val158Met genotype, which has been linked to heightened amygdala reactivity and deficits in prefrontal functioning, would be associated with brooding rumination and HRV, particularly among women with a history of past MDD. The results largely supported our hypotheses, providing additional support for relations among the different units of analysis for the Loss construct.

  15. The Brief Psychiatric Rating Scale (version 4.0) factorial structure and its sensitivity in the treatment of outpatients with unipolar depression.

    PubMed

    Zanello, Adriano; Berthoud, Laurent; Ventura, Joseph; Merlo, Marco C G

    2013-12-15

    The 24-item Brief Psychiatric Rating Scale (BPRS, version 4.0) enables the rater to measure psychopathology severity. Still, little is known about the BPRS's reliability and validity outside of the psychosis spectrum. The aim of this study was to examine the factorial structure and sensitivity to change of the BPRS in patients with unipolar depression. Two hundred and forty outpatients with unipolar depression were administered the 24-item BPRS. Assessments were conducted at intake and at post-treatment in a Crisis Intervention Centre. An exploratory factor analysis of the 24-item BPRS produced a six-factor solution labelled "Mood disturbance", "Reality distortion", "Activation", "Apathy", "Disorganization", and "Somatization". The reduction of the total BPRS score and dimensional scores, except for "Activation", indicates that the 24-item BPRS is sensitive to change as shown in patients that appeared to have benefited from crisis treatment. The findings suggest that the 24-item BPRS could be a useful instrument to measure symptom severity and change in symptom status in outpatients presenting with unipolar depression.

  16. A pilot study of heart rate variability biofeedback therapy in the treatment of perinatal depression on a specialized perinatal psychiatry inpatient unit.

    PubMed

    Beckham, A Jenna; Greene, Tammy B; Meltzer-Brody, Samantha

    2013-02-01

    Heart rate variability biofeedback (HRVB) therapy may be useful in treating the prominent anxiety features of perinatal depression. We investigated the use of this non-pharmacologic therapy among women hospitalized with severe perinatal depression. Three questionnaires, the State Trait Anxiety Inventory (STAI), Warwick-Edinburgh Mental Well-Being Scale, and Linear Analog Self Assessment, were administered to 15 women in a specialized inpatient perinatal psychiatry unit. Participants were also contacted by telephone after discharge to assess continued use of HRVB techniques. The use of HRVB was associated with an improvement in all three scales. The greatest improvement (-13.867, p < 0.001 and -11.533, p < 0.001) was among STAI scores. A majority (81.9 %, n = 9) of women surveyed by telephone also reported continued frequent use at least once per week, and over half (54.6 %, n = 6) described the use of HRVB techniques as very or extremely beneficial. The use of HRVB was associated with statistically significant improvement on all instrument scores, the greatest of which was STAI scores, and most women reported frequent continued use of HRVB techniques after discharge. These results suggest that HRVB may be particularly beneficial in the treatment of the prominent anxiety features of perinatal depression, both in inpatient and outpatient settings. PMID:23179141

  17. Carbon sequestration and eruption hazards

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2007-12-01

    In order to reduce the buildup of carbon dioxide in the atmosphere, proposals have been made to sequestrate carbon in ocean, or in coal mines and other underground formations. High gas concentration in ocean or underground formations has to potential to power gas-driven eruptions. In this presentation, possible eruption hazards are explored. Whenever carbon dioxide is sequestrated in the form of carbon dioxide gas, or dissolved and/or absorbed carbon dioxide, it is necessary to exercise caution to avoid gas-driven eruption hazard. It is long known that explosive volcanic eruptions are driven by H2O gas in magma. Lake eruptions powered by dissolved CO2 in lake bottom water were discovered in the 1980's (Kling et al., 1987; Zhang, 1996). Gas-driven ocean eruptions with mechanism similar to lake eruptions have been hypothesized (Zhang, 2003; Zhang and Kling, 2006) although not confirmed. Mud volcanos are commonly thought to be driven by methane-rich fluids in sediment (Milkov, 2000). Recently, Zhang et al. (2007) have proposed that coal outbursts in underground coal mines are driven by dissolved high CO2 concentration in coal, causing coal fragmentation and outburst. That is, coal outbursts may be regarded as a new type of gas-driven eruptions. Therefore, high concentrations of free gas or dissolved/absorbed gas may power eruptions of magma, lake water, ocean water, sediment, and coal. Gas- driven volcanic, lake and ocean eruptions are due to volume expansion from bubble growth, whereas gas-driven coal and sediment eruptions are due to high gas-pressure, leading to fragmentation of coal and sediment. (In explosive volcanism, magma fragmentation is also a critical point.) The threshold conditions for many of these eruptions are not known yet. In planning large (industrial) scale injection of CO2 into a natural reservoir, it is important to know the eruption threshold and design the injection scheme accordingly. More safe sequestration in terms of eruption hazards would

  18. Do bonding and bridging social capital affect self-rated health, depressive mood and cognitive decline in older Japanese? A prospective cohort study.

    PubMed

    Murayama, Hiroshi; Nishi, Mariko; Matsuo, Eri; Nofuji, Yu; Shimizu, Yumiko; Taniguchi, Yu; Fujiwara, Yoshinori; Shinkai, Shoji

    2013-12-01

    Little is known regarding the longitudinal effects of bonding and bridging social capital on health. This study examined the longitudinal associations of bonding and bridging social capital with self-rated health, depressive mood, and cognitive decline in community-dwelling older Japanese. Data analyzed in this study were from the 2010 (baseline) and 2012 (follow-up) Hatoyama Cohort Study. Bonding social capital was assessed by individual perception of homogeneity of the neighborhood (the level of homogeneity among neighbors) and of networks (the amount of homogeneous personal networks) in relation to age, gender, and socioeconomic status. Bridging social capital was assessed by individual perception of heterogeneity of networks (the amount of heterogeneous personal networks) in relation to age, gender, and socioeconomic status. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the effects of baseline social capital on poor health outcome at follow-up by logistic regression analysis. In total, 681 people completed baseline and follow-up surveys. The mean age of participants was 71.8 ± 5.1 years, and 57.9% were male. After adjusting for sociodemographics, lifestyle factors, comorbidity, functional capacity, baseline score of each outcome, and other bonding/bridging social capital, stronger perceived neighborhood homogeneity was inversely associated with poor self-rated health (OR = 0.55, 95% CI = 0.30-1.00) and depressive mood assessed by the Geriatric Depression Scale (OR = 0.58, 95% CI = 0.34-0.99). When participants who reported a depressive mood at baseline were excluded, stronger perceived heterogeneous network was inversely associated with depressive mood (OR = 0.40, 95% CI = 0.19-0.87). Neither bonding nor bridging social capital was significantly associated with cognitive decline assessed by the Mini-Mental State Examination. In conclusion, bonding and bridging social capital affect health in different ways, but they both have

  19. Geyser's Eruptive Activity in Broadband Seismic Records

    NASA Astrophysics Data System (ADS)

    Kugaenko, Yulia; Saltykov, Vadim

    2010-05-01

    River on June 3, 2007 and new dammed lake was formed in the Valley of the Geysers; a part of geysers has been destroyed and flooded). Some days the Big geyser was on the depth near 10 m. It got free from water in beginning of September, 2007 and reactivated. In September, 2009 eruptions were very active with the interval between them 55-60 min without quiet mode or pause in boiling. - The Pearl geyser eruptions are near 5 min., main cycle is 300-360 min. The height of fountain is 8-10 m. It is one of most picturesque geysers in the Valley. - The Gap geyser is the cone type geyser with stable rate and relatively shot cycle (33-34 min.). Eruptions are near 5 min. and not strong. The main feature of the Gap geyser is absence of boiling-effusion mode before eruption. For the large Big and Pearl geysers low-frequency seismic response on geyser's eruption was detected. Seismometer shows surface deformation caused by water-steam burst from the vent (or geyser eruption) with the period about 10-12 min. Slow vertical and radial displacements were recorded as travel of instrument's mass position. It was shown, that eruptions of the Big geyser are not constant. We can observe it in seismic records at different frequency bands. Some eruptions are weaker then other in low-frequency band (lesser then 0.01 Hz), but approximately similar for the range 20-50 Hz. It means possible deep variations of thermal supply. The weak short-period Gap geyser has high stability of eruptive activity in seismic records at frequency band 1-50 Hz. The correlation between envelops for different geyser's cycles exceeds 0.9. It demonstrates the invariability of thermal and water supply of this geyser. The seismic record of the eruption cycle starts with the activity increasing in intensity and amplitude, and than signal amplitude gradually decays until the final moment before an eruption. The amplitude decay was explained by (Kieffer, 1984) by an increased acoustic impedance mismatch between the two

  20. Winter depression and diabetes.

    PubMed

    Ernst, Christine R

    2012-12-01

    Depression is a common and often harmful disorder, which is frequently associated with the winter season. Research has shown a link between type 2 diabetes mellitus and depression. Furthermore, diabetics with depression have a higher rate of adverse outcomes. Little has been published regarding the seasonality of depression in diabetics. The case report described in this article concerns a 65-year-old woman with type 2 diabetes and a history of winter depression. Current evidence-based management options are reviewed. PMID:23089656

  1. Characterizing depression in borderline patients.

    PubMed

    Soloff, P H; George, A; Nathan, R S; Schulz, P M

    1987-04-01

    The comorbidity of depression and borderline disorder was studied in 39 symptomatic borderline inpatients defined by the Diagnostic Interview for Borderlines using three independent methods for assessing depression and three definitions of depression. Evaluations were conducted by the Schedule for Affective Disorders and Schizophrenia interviews for Research Diagnostic Criteria (RDC) depressive disorders, by clinical ratings for atypical depressive disorder, and by self-rated questionnaires for hysteroid dysphoria. Diagnoses of an RDC depression were made in 25 (64.1%), atypical depressive disorder in 16 (41%), and hysteroid dysphoria in 25 (64.1%) of the borderline patients. Two depressive diagnoses were present in 64.1% of patients, while 17.9% of patients met criteria for all three depressive disorders. No one method accurately characterized depression in borderline patients.

  2. Solar Eruptive Events

    NASA Technical Reports Server (NTRS)

    Holman, Gordon D.

    2012-01-01

    It s long been known that the Sun plays host to the most energetic explosions in the solar system. But key insights into the forms that energy takes have only recently become available. Solar flares have been phenomena of both academic and practical interest since their discovery in 1859. From the academic point of view, they are the nearest events for studying the explosive release of energy in astrophysical magnetized plasmas. From the practical point of view, they disrupt communication channels on Earth, from telegraph communications in 1859 to radio and television signals today. Flares also wreak havoc on the electrical power grid, satellite operations, and GPS signals, and energetic charged particles and radiation are dangerous to passengers on high-altitude polar flights and to astronauts. Flares are not the only explosive phenomena on the Sun. More difficult to observe but equally energetic are the large coronal mass ejections (CMEs), the ejection of up to ten billion tons of magnetized plasma into the solar wind at speeds that can exceed 1000 km/s. CMEs are primarily observed from the side, with coronagraphs that block out the bright disk of the Sun and lower solar atmosphere so that light scattered from the ejected mass can be seen. Major geomagnetic storms are now known to arise from the interaction of CMEs with Earth's magnetosphere. Solar flares are observed without CMEs, and CMEs are observed without flares. The two phenomena often occur together, however, and almost always do in the case of large flares and fast CMEs. The term solar eruptive event refers to the combination of a flare and a CME. Solar eruptive events generate a lot of heat: They can heat plasma to temperatures as high at 50 million Kelvin, producing radiation across the electromagnetic spectrum. But that s not all. A fascinating aspect of solar eruptive events is the acceleration of electrons and ions to suprathermal often relativistic energies. The accelerated particles are primarily

  3. The Tala Tuff, La Primavera caldera Mexico. Pre-eruptive conditions and magma processes before eruption

    NASA Astrophysics Data System (ADS)

    Sosa-Ceballos, G.

    2015-12-01

    La Primavera caldera, Jalisco Mexico, is a Pleistocenic volcanic structure formed by dome complexes and multiple pyroclastic flows and fall deposits. It is located at the intersection of the Chapala, Colima, and Tepic grabens in western Mexico. The first volcanic activity associated to La Primavera started ~0.1 Ma with the emission of pre-caldera lavas. The caldera collapse occurred 95 ka and is associated to the eruption of ~20 km3of pumice flows known as the Tala tuff (Mahood 1980). The border of the caldera was replaced by a series of domes dated in 75-30 ky, which partially filled the inner depression of the caldera with pyroclastic flows and falls. For more than a decade the Federal Commission of Electricity in Mexico (CFE) has prospected and evaluated the geothermal potential of the Cerritos Colorados project at La Primavera caldera. In order to better understand the plumbing system that tapped the Tala tuff and to investigate its relation with the potential geothermal field at La Primavera we performed a series of hydrothermal experiments and studied melt inclusions hosted in quartz phenocrysts by Fourier Infra red stectroscopy (FTIR). Although some post caldera products at La Primavera contain fayalite and quartz (suggesting QFM conditions) the Tala tuff does not contain fayalite and we ran experiments under NNO conditions. The absence of titanomagnetite does not allowed us to calculate pre-eruptive temperature. However, the stability of quartz and plagioclase, which are natural phases, suggest that temperature should be less than 750 °C at a pressure of 200 MPa. The analyses of H2O and CO2 dissolved in melt inclusions yielded concentrations of 2-5 wt.% and 50-100 ppm respectively. This data confirm that the pre-eruptive pressure of the Tala tuff is ~200 MPa and in addition to major elements compositions suggest that the Tala tuff is either, compositionally zoned or mixed with other magma just prior to eruption.

  4. An Eruption on Io

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2.5 million miles (4 million kilometers) from the spacecraft.

    Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun; beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself.

    The left image is a shorter exposure -- 3 milliseconds -- designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption.

    This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby.

    Most of those images will be stored onboard the spacecraft for downlink to Earth in March and April.

  5. [Terminology and manifestations of eruption disturbances].

    PubMed

    Janssen, K I; Raghoebar, G M; Visser, A; Vissink, A

    2014-04-01

    Eruption disturbances of teeth are not unusual; many variations are encountered and eruption disturbances can negatively influence the development of the tooth and jaw system. Causes of eruption disturbances can be categorized into general and local factors. The clinical spectrum of eruption disturbances involves syndromic and non-syndromic problems for both kinds of factors, varying from delayed eruption to primary failure of eruption. The following types of eruption disturbances should be distinguished: impaction, primary retention, secondary retention and primary failure of eruption. Early detection of eruption disturbances and timely and appropriate treatment of the various eruption disturbances play an important role in preventing the negative effects of eruption disturbances on the development of the dentition and the craniofacial skeleton.

  6. Possible effects of volcanic eruptions on stratospheric minor constituent chemistry

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Butler, D. M.

    1979-01-01

    Although stratosphere penetrating volcanic eruptions have been infrequent during the last half century, periods have existed in the last several hundred years when such eruptions were significantly more frequent. Several mechanisms exist for these injections to affect stratospheric minor constituent chemistry, both on the long-term average and for short-term perturbations. These mechanisms are reviewed and, because of the sensitivity of current models of stratospheric ozone to chlorine perturbations, quantitative estimates are made of chlorine injection rates. It is found that, if chlorine makes up as much as 0.5 to 1% of the gases released and if the total gases released are about the same magnitude as the fine ash, then a major stratosphere penetrating eruption could deplete the ozone column by several percent. The estimate for the Agung eruption of 1963 is just under 1% an amount not excluded by the ozone record but complicated by the peak in atmospheric nuclear explosions at about the same time.

  7. Explosive volcanism on Hecates Tholus, Mars - Investigation of eruption conditions

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, P. J.; Head, J. W., III; Wilson, L.

    1982-01-01

    From a reexamination of the medium and high-resolution Viking images of Amazonian and Hesperian age volcanic centers on Mars, it is believed that an excellent example of well-preserved explosive activity does indeed exist close to the summit of Hecates Tholus. A mantled region to the west of the summit caldera is seen as an example of a geologically very recent plinian air fall ash deposit. Morphological evidence is presented for describing this as explosively generated material, and numerical models of magma ascent and eruption in the Martian environment are used to estimate the physical characteristics (eruption cloud height, magma discharge rate, magma volatile content, duration of activity, and vent size) for this event. Attention is also given to the implication of this eruptive style for the composition of the erupted magma.

  8. Eruption probabilities for the Lassen Volcanic Center and regional volcanism, northern California, and probabilities for large explosive eruptions in the Cascade Range

    USGS Publications Warehouse

    Nathenson, Manuel; Clynne, Michael A.; Muffler, L.J. Patrick

    2012-01-01

    Chronologies for eruptive activity of the Lassen Volcanic Center and for eruptions from the regional mafic vents in the surrounding area of the Lassen segment of the Cascade Range are here used to estimate probabilities of future eruptions. For the regional mafic volcanism, the ages of many vents are known only within broad ranges, and two models are developed that should bracket the actual eruptive ages. These chronologies are used with exponential, Weibull, and mixed-exponential probability distributions to match the data for time intervals between eruptions. For the Lassen Volcanic Center, the probability of an eruption in the next year is 1.4x10-4 for the exponential distribution and 2.3x10-4 for the mixed exponential distribution. For the regional mafic vents, the exponential distribution gives a probability of an eruption in the next year of 6.5x10-4, but the mixed exponential distribution indicates that the current probability, 12,000 years after the last event, could be significantly lower. For the exponential distribution, the highest probability is for an eruption from a regional mafic vent. Data on areas and volumes of lava flows and domes of the Lassen Volcanic Center and of eruptions from the regional mafic vents provide constraints on the probable sizes of future eruptions. Probabilities of lava-flow coverage are similar for the Lassen Volcanic Center and for regional mafic vents, whereas the probable eruptive volumes for the mafic vents are generally smaller. Data have been compiled for large explosive eruptions (>≈ 5 km3 in deposit volume) in the Cascade Range during the past 1.2 m.y. in order to estimate probabilities of eruption. For erupted volumes >≈5 km3, the rate of occurrence since 13.6 ka is much higher than for the entire period, and we use these data to calculate the annual probability of a large eruption at 4.6x10-4. For erupted volumes ≥10 km3, the rate of occurrence has been reasonably constant from 630 ka to the present, giving

  9. Geology and eruptive mechanisms of Masaya Caldera Complex, Nicaragua

    SciTech Connect

    Williams, S.N.

    1983-01-01

    Results of detailed geologic field mapping and analysis of eruptive mechanisms at Masaya Caldera Complex, Nicaragua are presented. Eruptions began at least 50,000 and possibly 460,000 y.b.p. The Las Sierras Formation, regarded as Plio-Pleistocene in age, forms the local basement. A central vent of group or vents in the developing Masaya volcanic complex produced diverse deposits, all of basaltic composition. Eruption of a pyroclastic flow-surge sequence at 2250-6500 y.b.p. culminated in wholesale collapse of a caldera with a volume of 15.3 km/sup 3/. The bulk volume of the ignimbrite is 2.2-3.4 kkm/sup 3/ and the surge deposit is 4.9-5.5 km/sup 3/. Pre-historic lava production rates of 1.9-5.5 x 10/sup 6/ m/sup 3//year are similar to rates at other volcanoes but 26-76 times greater than the historic rate of production. The average lava effusion rate of 32 m/sup 3//sec during the 1772 eruption is at least an order of magnitude greater than observed effusion rates at other Central American volcanoes, and helps explain the unusual shield-like morphology of the volcano. Pyroclastic eruptions of several types have played an important role in the evolution of the volcano. Fissure-type eruptions, unknown elsewhere in Central America, have created numerous ash and scoria deposits. Two widespread scoria-fall deposits, locally known as the Fontana Lapilli an San Judas Formation, are the first documented plinian airfall deposts of basaltic composition. The Masaya-type caldera is redefined as a caldera associated with voluminous explosive eruptions of much less than 100 km/sup 3/ of mafic magma from a summit vent.

  10. [Masked depression].

    PubMed

    Preradović, M; Griva, D; Eror, S

    1991-01-01

    The study comprised 25 patients with masked depression and 30 patients with endogenous depression. According to the general characteristics both groups were homogenous and accordingly, comparable. Together with clinical evaluation of depressive syndrome, psychological management was applied. Rorschach test, Thematic Apperception Test and Minnesota Multiphasic Personality Inventory were used in the study. In the clinical picture of masked depressions somatovegetative disorders dominated and depressive behavior in endogenous depression. The frequence of suicid does not differ between patients with masked and endogenous depression.

  11. Petrology of the 2004-2006 Mount St. Helens lava dome -- implications for magmatic plumbing and eruption triggering: Chapter 30 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Pallister, John S.; Thornber, Carl R.; Cashman, Katharine V.; Clynne, Michael A.; Lowers, Heather; Mandeville, Charles W.; Brownfield, Isabelle K.; Meeker, Gregory P.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The question of new versus residual magma has implications for the long-term eruptive behavior of Mount St. Helens, because arrival of a new batch of dacitic magma from the deep crust could herald the beginning of a new long-term cycle of eruptive activity. It is also important to our understanding of what triggered the eruption and its future course. Two hypotheses for triggering are considered: (1) top-down fracturing related to the shallow groundwater system and (2) an increase in reservoir pressure brought about by recent magmatic replenishment. With respect to the future course of the eruption, similarities between textures and character of eruption of the 2004-6 dome and the long-duration (greater than 100 years) pre-1980 summit dome, along with the low eruptive rate of the current eruption, suggest that the eruption could continue sluggishly or intermittently for years to come.

  12. Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

    NASA Astrophysics Data System (ADS)

    Laakso, A.; Kokkola, H.; Partanen, A.-I.; Niemeier, U.; Timmreck, C.; Lehtinen, K. E. J.; Hakkarainen, H.; Korhonen, H.

    2015-08-01

    Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere. In addition, the recovery of the stratospheric sulfate burden and forcing was significantly faster in the concurrent case since the sulfate particles grew larger and thus sedimented faster from the stratosphere. In our simulation where we assumed that SRM would be stopped immediately after a volcano eruption, stopping SRM decreased the overall stratospheric aerosol load. For the same reasons, a volcanic eruption during SRM lead to only about 1/3 of the peak global ensemble-mean cooling compared to an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal was seen only for 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of the global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mt Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption

  13. Shallow conduit processes during the ad 1158 explosive eruption of Hekla volcano, Iceland

    NASA Astrophysics Data System (ADS)

    Janebo, Maria H.; Houghton, Bruce F.; Thordarson, Thorvaldur; Larsen, Gudrun

    2016-10-01

    Hekla is one of the most frequently active felsic volcanic systems in the world, with several known pre-historic large Plinian eruptions and 18 historical subplinian to small Plinian eruptions. A common view is that Plinian eruptions of Hekla are relatively short lived and purely explosive events. In detail, these events exhibit subtle differences in terms of deposit characteristics, reflecting significant differences in eruption behaviour. Of the 18 historical eruptions, two had bulk magma compositions with >66 wt% SiO2: a Plinian eruption in ad 1104 and a smaller, less well characterised, but atypical subplinian eruption in ad 1158. The ad 1158 eruption was a relatively sustained, dry (magmatic) eruption with a more powerful opening phase followed by a lower intensity, waning phase accompanied by minor destabilisation and collapse of the conduit walls. We examine here the dynamics of the ad 1158 eruption, focussing on the role of shallow conduit processes in modulating eruption dynamics. Vesicularity data constrain the relative influence of bubble nucleation, growth, and coalescence. The juvenile pyroclasts are composed of two types of microvesicular pumice (white and grey) with contrasting vesicle number density, vesicle-size distribution, and phenocryst and microlite contents. Textural analysis shows that these pumices reflect heterogeneity developed pre- to syn-eruptively in the conduit and that entrainment of longer resident magma by faster ascending magma permitted magma of contrasting maturity to be fragmented simultaneously. In this regard, the mixed melt of the ad 1158 eruption contrasts with the compositionally homogeneous melt phase of the more powerful ad 1104 Plinian event, which was typified by more uniform conduit and eruption dynamics accompanying higher average ascent rates.

  14. Measuring the speed of magma ascent during explosive eruptions of Kilauea, Hawaii

    NASA Astrophysics Data System (ADS)

    Ferguson, D. J.; Ruprecht, P.; Plank, T. A.; Hauri, E. H.; Gonnermann, H. M.; Houghton, B. F.; Swanson, D. A.

    2014-12-01

    The size and intensity of volcanic eruptions is controlled by a combination of the physical properties of magmas and the conditions of magma ascent. At basaltic volcanoes, where relatively fluid magmas are erupted, sustained explosive eruptions vary widely in style, from Hawaiian fountains erupted 10s to 100s of meter high to large Plinian type events, involving >20 km high eruption plumes. Decompression of magmas leads to volatile saturation and bubble growth, however it remains disputed how the dynamics of shallow ascent and degassing might control this disparate eruptive behaviour, or whether factors such as the initial volatile content exert the primary control on eruption style. A key issue is that the physical conditions of magma ascent, which may significantly impact eruptive dynamics, remain largely unconstrained by observational data. Here we quantify two primary variables - decompression rates and volatile contents - for magmas from three contrasting eruptions of Kīlauea volcano, Hawaii, using microanalysis and modelling of volatile diffusion along small melt tubes or embayments found in olivine crystals carried by the ascending magmas. During ascent decreasing solubility causes dissolved volatiles to diffuse along the embayment towards growing bubbles at the crystal edge. By modelling the diffusion of H2O, CO2 and S we obtain decompression rates, and indirectly ascent velocities, for the rising magma. For Hawaiian style fountaining events we obtain ascent rates of 0.05-0.07 MPa s-1 (~1 m s-1), whereas for a more intense subplinian eruption we obtain a notably faster rate of 0.29 MPa s-1 (>10m s-1). The timescales of melt transport from the storage region during these eruptions varied from around 3 to 40 minutes. We find no link between pre-eruptive volatile contents and eruption intensity, rather our results suggest that the eventual size of sustained explosive basaltic eruptions is likely governed by factors affecting the ascent velocity of melts in

  15. Volcanic Eruptions in Kamchatka

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Sheveluch Stratovolcano Click on the image for full resolution TIFF Klyuchevskoy Stratovolcano Click on the image for full resolution TIFF

    One of the most volcanically active regions of the world is the Kamchatka Peninsula in eastern Siberia, Russia. It is not uncommon for several volcanoes to be erupting at the same time. On April 26, 2007, the Advanced Spaceborne Thermal Emission and Reflection Radioneter (ASTER) on NASA's Terra spacecraft captured these images of the Klyuchevskoy and Sheveluch stratovolcanoes, erupting simultaneously, and 80 kilometers (50 miles) apart. Over Klyuchevskoy, the thermal infrared data (overlaid in red) indicates that two open-channel lava flows are descending the northwest flank of the volcano. Also visible is an ash-and-water plume extending to the east. Sheveluch volcano is partially cloud-covered. The hot flows highlighted in red come from a lava dome at the summit. They are avalanches of material from the dome, and pyroclastic flows.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  16. Contrasting grain size and componentry in complex proximal deposits of the 1886 Tarawera basaltic Plinian eruption

    NASA Astrophysics Data System (ADS)

    Carey, R. J.; Houghton, B. F.; Sable, J. E.; Wilson, C. J. N.

    2007-07-01

    is a large reduction of the physical and thermal ability of these vents to contribute to a stable high eruptive plume. Instead large volumes of ejecta were sedimented prematurely from shallow heights at rates an order of magnitude greater than for historical Strombolian, Hawaiian and subPlinian eruptions. This study illustrates that sustained powerful Plinian eruptions can be accompanied by heterogeneities and instabilities of the eruptive jet. At Tarawera, the record of complex proximal transport and deposition processes in the eruptive jet cannot be inferred from the eruption products at distances greater than 400 m from the eruptive fissure. We suggest that study of ultraproximal deposits, as seen at Mt Tarawera, provides the only opportunity to document the complex, dynamic behavior of the jet region of Plinian eruptions.

  17. Assessment of the atmospheric impact of volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Sigurdsson, H.

    1988-01-01

    The dominant global impact of volcanic activity is likely to be related to the effects of volcanic gases on the Earth's atmosphere. Volcanic gas emissions from individual volcanic arc eruptions are likely to cause increases in the stratospheric optical depth that result in surface landmass temperature decline of 2 to 3 K for less than a decade. Trachytic and intermediate magmas are much more effective in this regard than high-silica magmas, and may also lead to extensive ozone depletion due to effect of halogens and magmatic water. Given the assumed relationship between arc volcanism and subduction rate, and the relatively small variation in global spreading rates in the geologic record, it is unlikely that the rates of arc volcanism have varied greatly during the Cenozoic. Hotspot related basaltic fissure eruptions in the subaerial environment have a higher mass yield of sulfur, but lofting of the valcanic aerosol to levels above the tropopause is required for a climate impact. High-latitude events, such as the Laki 1783 eruption can easily penetrate the tropopause and enter the stratosphere, but formation of a stratospheric volcanic aerosol form low-latitude effusive basaltic eruptions is problematical, due to the elevated low-latitude tropopause. Due to the high sulfur content of hotspot-derived basaltic magmas, their very high mass eruption rates and the episodic behavior, hotspots must be regarded as potentially major modifiers of Earth's climate through the action of their volcanic volatiles on the chemistry and physics of the atmosphere.

  18. Explosion depths for phreatomagmatic eruptions

    NASA Astrophysics Data System (ADS)

    Valentine, Greg A.; Graettinger, Alison H.; Sonder, Ingo

    2014-05-01

    Subsurface phreatomagmatic explosions can result from the interaction of ascending magma with groundwater. Experiments over a wide range of energies show that for a given energy there is a depth below which an explosion will be contained within the subsurface (not erupt), and there is a corresponding shallower depth that will optimize ejecta dispersal. We combine these relationships with constraints on the energies of phreatomagmatic explosions at maar-diatreme volcanoes and show that most eruptions are likely sourced by explosions in the uppermost ~200 m, and even shallower ones (<100 m) are likely to dominate deposition onto tephra rings. Most explosions below ~200 m will not erupt but contribute to formation of, and to the vertical mixing of materials within, a diatreme (vent structure), with only rare very high energy explosions between ~200 and 500 m erupting. Similar constraints likely apply at other volcanoes that experience phreatomagmatic explosions.

  19. Voyager 2 Jupiter Eruption Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This movie records an eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over avery short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as 'spaghetti bowls'.

    As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  20. Factors of Hamilton Depression Rating Scale (17 items) at 2 weeks correlated with poor outcome at 1 year in patients with ischemic stroke.

    PubMed

    Yuan, Huaiwu; Zhang, Ning; Wang, Chunxue; Luo, Ben Yan; Shi, Yuzhi; Li, Jingjing; Zhou, Yong; Wang, Yilong; Zhang, Tong; Zhou, Juan; Zhao, Xingquan; Wang, Yongjun

    2014-02-01

    There was fewer paper about the relation between the Hamilton Depression Rating Scale (17 Items, HDRS-17) factors and stroke outcomes. Our aim was to investigate the influence of total score and factors of HDRS-17 on outcome of ischemic stroke at 1 year. A total of 1,953 patients with acute ischemic stroke were enrolled into a multicentered and prospective cohort study. The HDRS-17 was used to assess symptoms at 2 weeks after ischemic stroke. The Modified Ranking Scale (mRS) scores of 3-6 points and 0-2 points were regarded as poor outcome and benign outcome, respectively. At 1 year, 1,753 (89.8 %) patients had mRS score data. After adjusting for the confounders, patients with a total HDRS-17 score of ≥ 8 had a worse outcome at 1 year (OR = 1.62, 95 % CI 1.18-2.23). Symptoms of suicide (OR = 1.89, 95 % CI 1.27-2.83), decreased or loss of interest of work (OR = 1.89, 95 % CI 1.38-2.58), retardation (OR = 1.74, 95 % CI 1.27-2.38), psychic anxiety (OR = 1.72, 95 % CI 1.26-2.34), and agitation (OR = 1.61, 95 % CI 1.08-2.40) increased the risks for poor outcome by >60 %, respectively. Depressed mood, somatic anxiety, somatic symptoms-gastrointestinal, and early insomnia also increased the risk for poor outcome by nearly 50 %, respectively. A total HDRS-17 score of ≥ 8, and suicide, decreased or loss of interest of work, anxiety, agitation, retardation, depressed mood, somatic anxiety, somatic symptoms-gastrointestinal, and early insomnia of the HDRS-17 factors at 2 weeks after ischemic stroke increase the risk for poor outcome at 1 year.

  1. Fractal analysis of heart rate dynamics as a predictor of mortality in patients with depressed left ventricular function after acute myocardial infarction. TRACE Investigators. TRAndolapril Cardiac Evaluation

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Hoiber, S.; Kober, L.; Torp-Pedersen, C.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1999-01-01

    A number of new methods have been recently developed to quantify complex heart rate (HR) dynamics based on nonlinear and fractal analysis, but their value in risk stratification has not been evaluated. This study was designed to determine whether selected new dynamic analysis methods of HR variability predict mortality in patients with depressed left ventricular (LV) function after acute myocardial infarction (AMI). Traditional time- and frequency-domain HR variability indexes along with short-term fractal-like correlation properties of RR intervals (exponent alpha) and power-law scaling (exponent beta) were studied in 159 patients with depressed LV function (ejection fraction <35%) after an AMI. By the end of 4-year follow-up, 72 patients (45%) had died and 87 (55%) were still alive. Short-term scaling exponent alpha (1.07 +/- 0.26 vs 0.90 +/- 0.26, p <0.001) and power-law slope beta (-1.35 +/- 0.23 vs -1.44 +/- 0.25, p <0.05) differed between survivors and those who died, but none of the traditional HR variability measures differed between these groups. Among all analyzed variables, reduced scaling exponent alpha (<0.85) was the best univariable predictor of mortality (relative risk 3.17, 95% confidence interval 1.96 to 5.15, p <0.0001), with positive and negative predictive accuracies of 65% and 86%, respectively. In the multivariable Cox proportional hazards analysis, mortality was independently predicted by the reduced exponent alpha (p <0.001) after adjustment for several clinical variables and LV function. A short-term fractal-like scaling exponent was the most powerful HR variability index in predicting mortality in patients with depressed LV function. Reduction in fractal correlation properties implies more random short-term HR dynamics in patients with increased risk of death after AMI.

  2. Melting of ice by magma-ice-water interactions during subglacial eruptions as an indicator of heat transfer in subaqueous eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Magnús T.

    Eruptions within glaciers are characterized by fast cooling of volcanic deposits, rapid melting of ice and heating of meltwater. Heat transfer rates in subglacial eruptions may be monitored through melting rates of ice and simple calorimetric calculations used to infer heat fluxes and estimate the efficiency of heat transferfrom magma. Cooling models of effusive basaltic eruptions forming pillow lava indicate that thermal efficiency of such eruptions is 10-45%, and highest when the eruption rates are low and pillows are exposed to surrounding meltwater for a comparatively long time. When magma fragmentation occurs by non-explosive granulation or explosive activity the glass particles formed have diffusion times mainly in the range 10-3 s to 102 s depending on grain size, the mean being of the order of 1 s. Limited observational data on ice-melting rates and models of cooling times suggest that the efficiency of heat transfer from fragments may commonly be 70-80%. Correspondingly, total heat transfer rates associated with fragmentation are several times higher than for pillow lava at the same eruption rate. The contrasts in efficiency imply that variation in heat transfer rates during fragmentation may closely correlate with variations in magma eruption rate, whereas for pillow lava eruptions changes in heat transfer lag well behind changes in eruption rate. Though pillows may still have molten cores when buried in a growing volcanic pile, the temperature of volcanic glass created during subaqueous fragmentation should be no greater than 250-300°C at the time of deposition.

  3. IMPLOSION IN A CORONAL ERUPTION

    SciTech Connect

    Liu Rui; Wang Haimin; Alexander, David

    2009-05-01

    We present the observations of the contraction of the extreme-ultraviolet coronal loops overlying the flaring region during the preheating as well as the early impulsive phase of a GOES class C8.9 flare. During the relatively long, 6 minutes, preheating phase, hard X-ray (HXR) count rates at lower energies (below 25 keV) as well as soft X-ray fluxes increase gradually and the flare emission is dominated by a thermal looptop source with the temperature of 20-30 MK. After the onset of impulsive HXR bursts, the flare spectrum is composed of a thermal component of 17-20 MK, corresponding to the looptop emission, and a nonthermal component with the spectral index {gamma} = 3.5-4.5, corresponding to a pair of conjugate footpoints. The contraction of the overlying coronal loops is associated with the converging motion of the conjugate footpoints and the downward motion of the looptop source. The expansion of the coronal loops following the contraction is associated with the enhancement in H{alpha} emission in the flaring region, and the heating of an eruptive filament whose northern end is located close to the flaring region. The expansion eventually leads to the eruption of the whole magnetic structure and a fast coronal mass ejection. It is the first time that such a large scale contraction of the coronal loops overlying the flaring region has been documented, which is sustained for about 10 minutes at an average speed of {approx}5 km s{sup -1}. Assuming that explosive chromospheric evaporation plays a significant role in compensating for the reduction of the magnetic pressure in the flaring region, we suggest that a prolonged preheating phase dominated by coronal thermal emission is a necessary condition for the observation of coronal implosion. The dense plasma accumulated in the corona during the preheating phase may effectively suppress explosive chromospheric evaporation, which explains the continuation of the observed implosion up to {approx}7 minutes into the

  4. Depression and Parkinson's disease.

    PubMed

    Lemke, Matthias R; Fuchs, Gerd; Gemende, Irene; Herting, Birgit; Oehlwein, Christian; Reichmann, Heinz; Rieke, Jürgen; Volkmann, Jens

    2004-09-01

    Depression occurs in approximately 45% of all patients with Parkinson's disease (PD), reduces quality of life independent of motor symptoms and seems to be underrated and undertreated. Characteristics of symptoms differ from major depression. Because of overlapping clinical symptoms, diagnosis is based on subjectively experienced anhedonia and feeling of emptiness. Available rating scales for major depression may not be adequate to correctly measure severity of depression in PD. Anxiety and depression may manifest as first symptoms of PD many years before motor symptoms. Serotonergic, noradrenergic and dopaminergic mechanisms play key roles in the etiology of depression in PD. Tricyclic and newer, selective antidepressants including serotonin and noradrenaline reuptake inhibitors (SSRI, SNRI) appear to be effective in treating depression in PD. Selective reuptake inhibitors seem to have a favorable side effect profile. Recent controlled studies show antidepressant effects of pramipexole in bipolar II depression. New dopamine agonists pramipexole and ropinirole appear to ameliorate depressive symptoms in PD in addition to effects on motor symptoms. There is a lack of appropriate rating scales and controlled studies regarding depression in PD.

  5. Assessing Eruption Column Height in Ancient Flood Basalt Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2015-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at approximately 45 deg N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the approximately 180 km of known Roza fissure length could have supported approximately 36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (approximately 66 Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained

  6. Volcanic Lightning in Eruptions of Sakurajima Volcano

    NASA Astrophysics Data System (ADS)

    Edens, Harald; Thomas, Ronald; Behnke, Sonja; McNutt, Stephen; Smith, Cassandra; Farrell, Alexandra; Van Eaton, Alexa; Cimarelli, Corrado; Cigala, Valeria; Eack, Ken; Aulich, Graydon; Michel, Christopher; Miki, Daisuke; Iguchi, Masato

    2016-04-01

    In May 2015 a field program was undertaken to study volcanic lightning at the Sakurajima volcano in southern Japan. One of the main goals of the study was to gain a better understanding of small electrical discharges in volcanic eruptions, expanding on our earlier studies of volcanic lightning at Augustine and Redoubt volcanoes in Alaska, USA, and Eyjafjallajökull in Iceland. In typical volcanic eruptions, electrical activity occurs at the onset of an eruption as a near-continual production of VHF emissions at or near to the volcanic vent. These emissions can occur at rates of up to tens of thousands of emissions per second, and are referred to as continuous RF. As the ash cloud expands, small-scale lightning flashes of several hundred meters length begin to occur while the continuous RF ceases. Later on during the eruption larger-scale lightning flashes may occur within the ash cloud that are reminiscent of regular atmospheric lightning. Whereas volcanic lightning flashes are readily observed and reasonably well understood, the nature and morphology of the events producing continuous RF are unknown. During the 2015 field program we deployed a comprehensive set of instrumentation, including a 10-station 3-D Lightning Mapping Array (LMA) that operated in 10 μs high time resolution mode, slow and fast ΔE antennas, a VHF flat-plate antenna operating in the 20-80 MHz band, log-RF waveforms within the 60-66 MHz band, an infra-red video camera, a high-sensitivity Watec video camera, two high-speed video cameras, and still cameras. We give an overview of the Sakurajima field program and present preliminary results using correlated LMA, waveforms, photographs and video recordings of volcanic lightning at Sakurajima volcano.

  7. Total electron content anomalies associated with global VEI4 + volcanic eruptions during 2002-2015

    NASA Astrophysics Data System (ADS)

    Li, Wang; Guo, Jinyun; Yue, Jianping; Shen, Yi; Yang, Yang

    2016-10-01

    In previous studies, little attention has been paid to the total electron content (TEC) anomalies preceding the volcanic eruption. We analyze the coupling relationship between volcanic eruption and TEC anomalies, and discuss the spatial distribution of TEC anomalies associated with volcanic geographical location. We utilize the global ionosphere map (GIM) data from the Center for Orbit Determination in Europe (CODE) to analyze TEC variations before the global volcanic eruptions indicated by VEI (Volcanic Explosivity Index) 4 + from 2002 to 2015 with the sliding interquartile range method. The results indicate the occurrence rate of TEC anomalies before great volcanic eruptions is related with the volcanic type and geographical position. The occurrence rate of TEC anomalies before stratovolcano and caldera eruptions is higher than that before shield and pyroclastic shield eruptions, and the occurrence rate of TEC anomalies has a descending trend from low latitudes to high latitudes. The TEC anomalies before the volcanic eruptions in low-mid latitudes are within the volcanic affected areas, but do not coincide with the volcanic foci. The corresponding TEC anomalies could be observed in the conjugated region, and all the TEC anomalies in the volcanic affected areas are usually close to bounds of equatorial anomaly zones. However, the TEC anomalies preceding these eruptions in high latitudes usually surround the volcano, and no TEC anomalies appear in the conjugated region. These conclusions have potential applications to the prediction of great volcanic eruptions in the future.

  8. Infrasound research of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Ripepe, Maurizio

    2016-04-01

    Volcanic eruptions are efficient sources of infrasound produced by the rapid perturbation of the atmosphere by the explosive source. Being able to propagate up to large distances from the source, infrasonic waves from major (VEI 4 or larger) volcanic eruptions have been recorded for many decades with analogue micro-barometers at large regional distances. In late 1980s, near-field observations became progressively more common and started to have direct impact on the understanding and modeling of explosive source dynamics, to eventually play a primary role in volcano research. Nowadays, infrasound observation from a large variety of volcanic eruptions, spanning from VEI 0 to VEI 5 events, has shown a dramatic variability in terms of signature, excess pressure and frequency content of radiated infrasound and has been used to infer complex eruptive source mechanisms for the different kinds of events. Improved processing capability and sensors has allowed unprecedented precise locations of the explosive source and is progressively increasing the possibility to monitor volcanoes from distant records. Very broadband infrasound observations is also showing the relation between volcanic eruptions and the atmosphere, with the eruptive mass injection in the atmosphere triggering acoustic-gravity waves which eventually might control the ash dispersal and fallout.

  9. Solar Activity and Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2006-01-01

    Our Sun is a dynamic, ever-changing star. In general, its atmosphere displays major variation on an 11-year cycle. Throughout the cycle, the atmosphere occasionally exhibits large, sudden outbursts of energy. These "solar eruptions" manifest themselves in the form of solar flares, filament eruptions, coronal mass ejections (CMEs), and energetic particle releases. They are of high interest to scientists both because they represent fundamental processes that occur in various astrophysical context, and because, if directed toward Earth, they can disrupt Earth-based systems and satellites. Research over the last few decades has shown that the source of the eruptions is localized regions of energy-storing magnetic field on the Sun that become destabilized, leading to a release of the stored energy. Solar scientists have (probably) unraveled the basic outline of what happens in these eruptions, but many details are still not understood. In recent years we have been studying what triggers these magnetic eruptions, using ground-based and satellite-based solar observations in combination with predictions from various theoretical models. We will present an overview of solar activity and solar eruptions, give results from some of our own research, and discuss questions that remain to be explored.

  10. The location and timing of magma degassing during Plinian eruptions

    NASA Astrophysics Data System (ADS)

    Giachetti, T.; Gonnermann, H. M.

    2014-12-01

    Water is the most abundant volatile species in explosively erupting silicic magmas and significantly affects magma viscosity, magma fragmentation and the dynamics of the eruption column. The effect that water has on these eruption processes can be modulated by outgassing degassing from a permeable magma. The magnitude, rate and timing of outgassing during magma ascent, in particular in relation to fragmentation, remains a subject of debate. Here we constrain how much, how fast and where the erupting magma lost its water during the 1060 CE Plinian phase of the Glass Mountain eruption of Medicine Lake Volcano, California. Using thermogravimetric analysis coupled with numerical modeling, we show that the magma lost >90% of its initial water upon eruption. Textural analyses of natural pumices, together with numerical modeling of magma ascent and degassing, indicate that 65-90% of the water exsolved before fragmentation, but very little was able to outgas before fragmentation. The magma attained permeability only within about 1 to 10 seconds before fragmenting and during that time interval permeable gas flow resulted in only a modest amount of gas flux from the un-fragmented magma. Instead, most of the water is lost shortly after fragmentation, because gas can escape rapidly from lapilli-size pyroclasts. This results in an efficient rarefaction of the gas-pyroclast mixture above the fragmentation level, indicating that the development of magma permeability and ensuing permeable outgassing are a necessary condition for sustain explosive eruptions of silicic magma. Magma permeability is thus a double-edged sword, it facilitates both, the effusive and the explosive eruption of silicic magma.

  11. Crust-ocean interactions during midocean ridge eruptions

    NASA Astrophysics Data System (ADS)

    Baker, E. T.

    2011-12-01

    Eruptions are the "quantum event" of crustal accretion, occurring daily to monthly (depending on spreading rate) along the global midocean ridge system. The number of eruptions detected and responded to remain very few, however, so our knowledge of the magnitude and rate of crust-ocean interaction at the instant of an eruption is almost entirely circumstantial. The discovery of uniquely different plumes over a 2008 eruption on the NE Lau spreading center greatly broadened the known range of eruption-initiated transfer of heat, chemicals, and perhaps biota from the crust to the ocean. Serendipitous observations and rapid response cruises have now documented that the "event (mega-) plumes" accompanying eruptions range over a factor of 100 in volume (1-150 km3), yet maintain a distinctive and consistent chemical signature (much lower 3He/heat and Mn/heat and higher H2/heat than typical black smokers). Confirmed event plumes have formed at spreading rates from 55-~90 mm/yr, with some incompletely sampled but "event-like" plumes observed at even slower rates (11-30 mm/yr; Gakkel and Carlsberg Ridges). Presently, only four event plumes can be associated with specific eruptions. Large event plumes in the NE Pacific were found over thick (up to ~75 m), voluminous, and slowly extruded pillow mounds. The 2008 eruption on the fast-spreading NE Lau spreading center demonstrated that thin (a few meters), small, and rapidly emplaced sheet flows can generate smaller event plumes. Available evidence suggests that massive fluid discharge occurs virtually simultaneously with an eruption. At Gorda Ridge in 1996, eruption-indicative seismicity began on the same day and location an event plume was found. At Axial Volcano in 1998, moorings 2 km apart both recorded the appearance of a >100-m-thick plume within minutes of the start of a 72-min-long sheet flow eruption. These observations support inferences from plume modeling and chemistry that event plume generation time is hours, not

  12. Dynamics of the plinian eruptive phase of Laacher See Volcano (Eifel, West Germany)

    SciTech Connect

    Bogaard, P.V.D.; Schmincke, H.U.

    1985-01-01

    Phonolitic tuffs, erupted by Laacher See Volcano 11,000 a B.P., cover some 700,000 km/sup 2/ in Central and Northern Europe, form an important marker in Late Glacial sedimentary sections, and comprise some 5 km/sup 3/ phonolite magma (DRE). Some 80% of the magma was erupted during two major Plinian eruptive phases, which produced an airfall pumice bed and an overlying sequence of ash flow deposits and intercalated fallout pumice and are separated by a minor phreatomagmatic eruptive phase (MLST A). Ballistic blocks up to 1.5 m in diameter are abundant in near-vent deposits from most eruptive phases. With transport ranges up to 2.5 km, the ballistic blocks indicate initial velocities of the Plinian eruption columns of c. 300-350 m/s, which fits magmatic gas releases of 2-2.5 wt.-% (H/sub 2/O). Mass eruption rates are estimated as 3x10/sup 8/ to 4x10/sup 8/ kg/s, corresponding to vent radii of 200-250 m. The change in eruption style from a sustained Plinian column to repeatedly collapsing and recovering Plinian eruption columns is interpreted in terms of an interplay of vent erosion and volcanotectonic faulting during a 1 km lateral displacement of the eruptive vent.

  13. Scoria cone formation through a violent Strombolian eruption: Irao Volcano, SW Japan

    NASA Astrophysics Data System (ADS)

    Kiyosugi, Koji; Horikawa, Yoshiyuki; Nagao, Takashi; Itaya, Tetsumaru; Connor, Charles B.; Tanaka, Kazuhiro

    2014-01-01

    Scoria cones are common volcanic features and are thought to most commonly develop through the deposition of ballistics produced by gentle Strombolian eruptions and the outward sliding of talus. However, some historic scoria cones have been observed to form with phases of more energetic violent Strombolian eruptions (e.g., the 1943-1952 eruption of Parícutin, central Mexico; the 1975 eruption of Tolbachik, Kamchatka), maintaining volcanic plumes several kilometers in height, sometimes simultaneous with active effusive lava flows. Geologic evidence shows that violent Strombolian eruptions during cone formation may be more common than is generally perceived, and therefore it is important to obtain additional insights about such eruptions to better assess volcanic hazards. We studied Irao Volcano, the largest basaltic monogenetic volcano in the Abu Monogenetic Volcano Group, SW Japan. The geologic features of this volcano are consistent with a violent Strombolian eruption, including voluminous ash and fine lapilli beds (on order of 10-1 km3 DRE) with simultaneous scoria cone formation and lava effusion from the base of the cone. The characteristics of the volcanic products suggest that the rate of magma ascent decreased gradually throughout the eruption and that less explosive Strombolian eruptions increased in frequency during the later stages of activity. During the eruption sequence, the chemical composition of the magma became more differentiated. A new K-Ar age determination for phlogopite crystallized within basalt dates the formation of Irao Volcano at 0.4 ± 0.05 Ma.

  14. Caregiver Depression

    MedlinePlus

    ... will not sell or share your name. Caregiver Depression Tweet Bookmark this page | Email | Print Many caregivers ... depression See your doctor Treatment Coping Symptoms of depression Caregiving is hard — and can lead to feelings ...

  15. Postpartum depression

    MedlinePlus

    Depression - postpartum; Postnatal depression; Postpartum psychological reactions ... The exact causes of postpartum depression are unknown. Changes in hormone levels during and after pregnancy may affect a woman's mood. Many non-hormonal factors may also ...

  16. The mechanism of volcanic eruptions (a steady state approach)

    NASA Astrophysics Data System (ADS)

    Slezin, Yu. B.

    2003-03-01

    A theory of a volcanic eruption as a steady magma flow from a magma chamber to the surface is described. Magma is considered as a two-component two-phase medium and magma flow is steady, one-dimensional and isothermal. Mass and momentum exchange between condensed and gaseous phases is assumed to be in equilibrium with nucleation of bubbles as a fast process at small oversaturations. Three basic flow structures in a conduit are recognized and three resulting types of eruption are described. (1) In the discrete gas separation (DGS) flow, melt with discrete gas bubbles erupts. This type includes lava eruptions and Strombolian activity. (2) In the dispersion regime there is continuous eruption of a gas-pyroclastic suspension. Catastrophic explosive eruptions are included in this type. (3) Here a partly destroyed foam is erupted with permeable structure that allows gas escape. Near the surface this structure evolves with an increase in permeability and a decrease in the total porosity. This type corresponds to lava dome extrusions. A criterion dividing DGS flow from the other two regimes is obtained: Di= Uηn1/3a/ c0, where U is the magma ascent velocity, η is magma viscosity, n is number of bubble nuclei in a unit mass of magma, a is the solubility coefficient for volatiles in magma and c0 is the volatile content. The boundary between the dispersion regime and the partly destroyed foam regime depends on U, c0 and particle size d p. For the dispersion regime the basic governing parameters are: magma chamber depth H, conduit conductivity σ= b2/ η ( b is the characteristic cross-dimension of the conduit), and excess pressure in the magma chamber. Instability of the dispersion regime is investigated numerically. The dependence of magma discharge rate on the governing parameters is described as a combination of equilibrium surfaces with cusp catastrophes. Magma chamber depth is a 'splitting' parameter in most cusps and controls the existence of unstable magma flow with

  17. A model of vulcanian eruptions at Galeras volcano, Colombia

    NASA Astrophysics Data System (ADS)

    Stix, John; Torres, Roberto C.; Narváez M, Lourdes; Cortés J, Gloria Patricia; Raigosa, Jaime A.; Gómez M, Diego; Castonguay, Robert

    1997-05-01

    A series of six vulcanian eruptions at Galeras volcano, Colombia, occurred during 1992-1993. These eruptions followed the emplacement of a lava dome in late 1991, which was accompanied by cooling, crystallizing and partial solidification of the column of magma plugging the conduit. Five of the eruptions were preceded by episodes of monochromatic long-period seismicity, suggesting cyclic pressurization of the magma. The quiescent intervals between eruptions generally decreased with each successive eruption. We propose a model of gas release from magma into confined, stationary pore spaces by 5-10% crystallization of anhydrous minerals, causing repeated overpressurization of the magmatic system. Using initial lithostatic pressures of 20-100 MPa (800-3900 m depth), gas buildup by crystallization indicates overpressures of 3-17 MPa, which is the approximate fracture criterion for a magma chamber. Our Galeras data suggest two models of pressurization: (1) gas exsolution may have occurred at similar depths, but with progressively smaller overpressures being developed before each successive eruption. According to this model, the comparatively long quiescent periods between the first eruptions resulted in relatively large amounts of gas exsolution from the magma and accumulation in pore spaces, whereas the shorter quiescent periods for the later eruptions exsolved less gas. The decrease in overpressure with time may have resulted from progressive fracturing of partly solidified magma during the eruptions, which progressively decreased the tensile strength and increased the permeability of the magma. (2) Since overpressures are smaller at shallower depths for a given amount of crystallization, the first eruptions of 1992-1993 were caused by gas exsolution at shallow depths, while the last eruptions, having shorter quiescent intervals, resulted from a greater amount of gas exsolution at greater depths. In this case, the rate of gas exsolution varied as a function of depth

  18. Disentangling the eruption source parameters that control the climate effects of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Marshall, Lauren; Schmidt, Anja; Mann, Graham; Carslaw, Kenneth; Dhomse, Sandip; Haywood, Jim; Jones, Andy

    2016-04-01

    Climatic cooling in the 1-2 years following a major volcanic eruption does not scale linearly with the mass of SO2 injected into the atmosphere. The injection height of the emissions, the latitude of the volcano, the season and large scale atmospheric circulations, also influence the climatic response. Complex couplings exist between stratospheric chemistry and circulations, and aerosol induced heating and aerosol microphysical processes such as condensation and evaporation. As yet, there has been no systematic assessment of these relationships when considering different eruption source parameters. A series of simulations with a global composition-climate model with interactive stratospheric chemistry and aerosol microphysics are conducted, in which the eruption latitude and injection height are varied. Parameter combinations are chosen such that injections sample areas in the atmosphere where different chemical and dynamical influences are important (e.g. tropical vs. high latitude eruptions, injections near the tropopause vs. injections in the upper stratosphere). Each experiment is repeated for varying SO2 injection magnitudes. We focus on the analysis of aerosol properties such as the stratospheric aerosol optical depth, effective radius and heating rates, and resultant perturbations to radiative fluxes. Initial results demonstrate the non-linearity in the climatic response as the injection magnitude is increased. Future work will focus on disentangling the contribution of each parameter to the climatic response with additional simulations to investigate the effect of season and the Quasi Biennial Oscillation. Results will aid in the understanding of the impact of past, present and future volcanic eruptions. By analysing sulfate deposition to the polar ice caps, we will assess the uncertainty in, and validity of, the historic volcanic radiative forcing deduced from ice cores.

  19. Unusual Patterns of Seismicity during Eruptive and Non-eruptive Periods at the Persistently Restless Telica Volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Rodgers, Melanie J.

    Telica Volcano, Nicaragua, is a persistently restless volcano with high rates of seismicity that can vary from less than ten events to over a thousand events per day. Low-frequency (LF) events dominate the seismic catalogue and seismicity rates at Telica show little clear correlation with periods of eruption. As such, traditional methods of forecasting of volcanic activity based on increases in seismicity and recognition of LF activity are not applicable. A single seismic station has been operating at Telica since 1993, and in 2010 we installed a broadband seismic and continuous GPS network (TESAND network) at Telica. In this study we investigate the seismic characteristics surrounding a nine-month period of phreatic to phreatomagmatic explosions in 1999, and also from the initial three-and-a-half year deployment of the TESAND network, including a three-month phreatic vulcanian eruptive period in 2011. We demonstrate that pertinent information can be obtained from analysis of single-station data, and while large seismic networks are preferable when possible, we note that for many volcanoes this is not possible. We find unusual patterns of seismicity before both eruptive periods; rather than a precursory increase in seismicity as is observed prior to many volcanic eruptions, we observe a decrease in seismicity many months prior to eruption. We developed a new program for cross-correlation of large seismic data catalogues and analysed multiplet activity surrounding both eruptive periods. We observed that the formation of new multiplets corresponds to periods of high event rates (during inter-eruptive periods) and high percentages of daily events that belong to a multiplet. We propose a model for the seismicity patterns observed at Telica, where changes in seismicity are related to a cyclic transition between open-system degassing and closed-system degassing. Periods of open-system degassing occur during non-eruptive episodes and are characterised by high event rates

  20. Eruptions from the Sun

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  1. Bullying in adolescence: psychiatric problems in victims and bullies as measured by the Youth Self Report (YSR) and the Depression Self-Rating Scale (DSRS).

    PubMed

    Ivarsson, Tord; Broberg, Anders G; Arvidsson, Tomas; Gillberg, Christopher

    2005-01-01

    Adolescents in junior high school (n = 237), completed a questionnaire on bullying as it relates to victim and to perpetrator status, suicidality and biographical data. Psychological symptoms were assessed by the Youth Self Report (YSR) and the Depression Self-Rating Scale (DSRS) supplemented by school health officers blind assessments. Bullying was common: bully only (18%), victim only (10%) and victim and bully (9%). Bullies had mainly externalizing symptoms (delinquency and aggression) and those of the victim and bully group both externalizing and internalizing symptoms as well as high levels of suicidality. Adolescents in the bully only group were more likely to be boys and to have attention problems. Moreover, a substantial proportion of the adolescents in the victim only group were judged by school health officer to have psychiatric symptoms and to function socially less well. PMID:16757465

  2. Depressed rates of origination and extinction during the late Paleozoic ice age: A new state for the global marine ecosystem

    NASA Astrophysics Data System (ADS)

    Stanley, Steven M.; Powell, Matthew G.

    2003-10-01

    Rates of origination and extinction for marine animal genera dropped to low levels in latest Mississippian time, immediately after massive glaciers formed in the Southern Hemisphere and a second-order mass extinction occurred. Evolutionary turnover and diversity remained low for ˜50 m.y., shifting markedly upward precisely when extensive glaciation ended in Early Permian time. All diverse taxa with good fossil records experienced low rates of origination and extinction during this major ice age. Such sluggish rates would be predicted for faunas of shallow seas on or adjacent to a heavily glaciated supercontinent such as Pangea, where cool and highly seasonal thermal regimes should dictate that species have broad ecological niches, widespread geographic distributions, and large and relatively stable populations.

  3. Depression in the elderly.

    PubMed Central

    Wasylenki, D.

    1980-01-01

    Depression in the elderly is very common and may be difficult to diagnose. Because of its varied presentation and its frequent association with physical illness it will be encountered increasingly by all physicians as the elderly population expands. Depression, though treatable, is often not treated, and suicide rates are high among depressed elderly persons. Diagnostic difficulties lie in distinguishing depression from organic brain syndromes, from so-called masked depressions and from normal grief reactions. Pharmacologic treatment is effective, but care must be taken to recognize side effects and to use adequate doses. Psychologic approaches should focus on reducing feelings of helplessness and failing self-esteem. The importance of the losses borne by elderly persons in the pathogenesis of depression continues to be of theoretical and practical interest. PMID:6989463

  4. An Analysis of Relapse Rates and Predictors of Relapse in 2 Randomized, Placebo-Controlled Trials of Desvenlafaxine for Major Depressive Disorder

    PubMed Central

    Fayyad, Rana S.; Guico-Pabia, Christine J.

    2015-01-01

    Objective: To evaluate relapse rates and predictors of relapse in 2 randomized, placebo-controlled trials of desvenlafaxine for major depressive disorder (MDD). Method: Study 1: week 8 responders to open-label desvenlafaxine 50 mg/d entered a 12-week open-label stability phase. Patients with a continuing, stable response at week 20 were randomly assigned to 6-month, double-blind treatment (desvenlafaxine 50 mg/d or placebo). Study 1 was conducted between June 2009 and March 2011 at 87 sites worldwide. Study 2: week 12 responders to open-label desvenlafaxine 200 or 400 mg/d were randomly assigned to 6-month, double-blind treatment (desvenlafaxine 200 mg/d, 400 mg/d, or placebo). Study 2 was conducted between June 2003 and August 2005 at 49 sites in Europe, the United States, and Taiwan. Relapse was assessed separately by study with log-rank test using protocol definitions of relapse and with 17-item Hamilton Depression Rating Scale (HDRS-17) score ≥ 16 at any time during the double-blind phase. Kaplan-Meier estimates evaluated time to relapse, censoring data at months 1, 2, and 3 and overall; treatments were compared using hazard ratios. Cox proportional hazards models assessed relapse predictors. Results: Overall relapse rates for all definitions were significantly lower for desvenlafaxine versus placebo for both studies (all P ≤ .002). In study 1, rates were significantly lower for desvenlafaxine versus placebo at month 2 (P = .016) and month 3 (P = .007) using the protocol definition. In study 2, relapse rates were significantly lower for desvenlafaxine versus placebo at months 1, 2, and 3 for both definitions (P < .0001–.002). Hazard ratios were similar at months 1, 2, and 3 and overall for both studies (0.382–0.639). Conclusions: Desvenlafaxine 50 to 400 mg/d effectively prevented relapse at 6 months. Desvenlafaxine significantly prevented relapse early (month 1) versus placebo only in study 2. Trial Registration: ClinicalTrials.gov identifiers

  5. Pre-eruptive storage conditions and eruption dynamics of a small rhyolite dome: Douglas Knob, Yellowstone volcanic field, USA

    NASA Astrophysics Data System (ADS)

    Befus, Kenneth S.; Zinke, Robert W.; Jordan, Jacob S.; Manga, Michael; Gardner, James E.

    2014-03-01

    The properties and processes that control the size, duration, and style of eruption of rhyolite magma are poorly constrained because of a paucity of direct observations. Here, we investigate the small-volume, nonexplosive end-member. In particular, we determine the pre-eruptive storage conditions and eruption dynamics of Douglas Knob, a 0.011-km3 obsidian dome that erupted from a 500-m-long fissure in the Yellowstone volcanic system. To determine pre-eruptive storage conditions, we analyzed compositions of phenocrysts, matrix glass, and quartz-hosted glass inclusions by electron microprobe and Fourier-transform infrared analyses. The pre-eruptive melt is a high-silica rhyolite (˜75 wt.% SiO2) and was stored at 760 ± 30 °C and 50 ± 25 MPa prior to eruption, assuming vapor saturation at depth. To investigate emplacement dynamics and kinematics, we measured number densities and orientations of microlites at various locations across the lava dome. Microlites in samples closest to the inferred fissure vent are the most aligned. Alignment does not increase with distance traveled away from the vent, suggesting microlites record conduit processes. Strains of <5 accumulated in the conduit during ascent after microlite formation, imparted by a combination of pure and simple shear. Average microlite number density in samples varies from 104.9 to 105.7 mm-3. Using the magma ascent model of Toramaru et al. (J Volcanol Geotherm Res 175:156-157, 2008), microlite number densities imply decompression rates ranging from 0.03 to 0.11 MPa h-1 (˜0.4-1.3 mm s-1 ascent rates). Such slow ascent would allow time for passive degassing at depth in the conduit, thus resulting in an effusive eruption. Using calculated melt viscosity, we infer that the dike that fed the eruption was 4-8 m in width. Magma flux through this dike, assuming fissure dimensions at the surface represent its geometry at depth, implies an eruption duration of 17-210 days. That duration is also consistent with the

  6. Oral antibody to interleukin-10 reduces growth rate depression due to Eimeria spp. infection in broiler chickens.

    PubMed

    Sand, Jordan M; Arendt, Maria K; Repasy, Alec; Deniz, Gűlay; Cook, Mark E

    2016-02-01

    Eimeria spp. must be controlled in floor-reared poultry to prevent the onset of coccidiosis. Here we use an oral antibody to chicken IL-10 to prevent growth depression due to Eimeria spp. infection. Egg antibody directed against an antigenic peptide of IL-10 was produced in laying hens and measured using an ELISA. In the first experiment, egg yolk powder containing antibody to chicken IL-10 (vlpramqt conjugate) (anti-IL-10 yolk powder) was fed at 3.4 g/kg feed to determine growth response following mixed Eimeria spp. challenge. Chicks were fed either anti-IL-10 antibodies or control antibodies and challenged (d3) with either sterile saline or a 10× attenuated Eimeria spp. vaccine. Control-fed and Eimeria-challenged chicks grew 8.8% slower than those challenged with saline (P < 0.04), whereas anti-IL-10-fed Eimeria challenged chicks were not different from untreated controls. In the second trial a dose response was performed with doses of either 0 (control antibody), 0.34-, or 3.4-g anti-IL-10 yolk powder/kg feed. Control-fed, Eimeria-challenged chicks grew 10.6% slower than control saline-challenged chicks (P < 0.05); however, anti-IL-10-fed chicks fed either dose of anti-IL-10 were not different from saline-challenged chicks. Finally, the effect of anti-IL-10 on acquired immunity was investigated. Chicks were fed control or anti-IL-10 yolk powder and vaccinated with a 1× dose of Eimeria vaccine at d 3. After 14 d, antibody was removed from the diet. Chicks were either saline or 10× Eimeria challenged at d 17. We found that the anti-IL-10-fed chickens did not show a reduction in growth due to challenge; hence anti-IL-10 does not appear to affect adaptive immunity during the primary immunization. Overall, use of an antibody to IL-10 is a novel method in preventing adverse effects of Eimeria spp. infection in poultry. PMID:26772659

  7. Featured Image: Solar Prominence Eruptions

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-02-01

    In these images from the Solar Dynamics Observatorys AIA instrument (click for the full resolution!), two solar prominence eruptions (one from June 2011 and one from August 2012) are shown in pre- and post-eruption states. The images at the top are taken in the Fe XII 193 bandpass and the images at the bottom are taken in the He II 304 bandpass. When a team of scientists searched through seven years of solar images taken by the STEREO (Solar Terrestrial Relations Observatory) spacecraft, these two eruptions were found to extend all the way out to a distance of 1 AU. They were the only two examples of clear, bright, and compact prominence eruptions found to do so. The scientists, led by Brian Wood (Naval Research Laboratory), used these observations to reconstruct the motion of the eruption and model how prominences expand as they travel away from the Sun. Theimage to the rightshowsa STEREO observation compared to the teams 3D model of theprominences shape and expansion. To learn more about theresults from this study, check out the paper below.CitationBrian E. Wood et al 2016 ApJ 816 67. doi:10.3847/0004-637X/816/2/67

  8. Volcano seismicity and ground deformation unveil the gravity-driven magma discharge dynamics of a volcanic eruption.

    PubMed

    Ripepe, Maurizio; Donne, Dario Delle; Genco, Riccardo; Maggio, Giuseppe; Pistolesi, Marco; Marchetti, Emanuele; Lacanna, Giorgio; Ulivieri, Giacomo; Poggi, Pasquale

    2015-01-01

    Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior of the crust to the surface. The eruption is modelled as a gravity-driven drainage of magma stored in the volcanic edifice with a minor contribution of magma supplied at a steady rate from a deep reservoir. Here we show that the discharge rate can be predicted by the contraction of the volcano edifice and that the very-long-period seismicity migrates downwards, tracking the residual volume of magma in the shallow reservoir. Gravity-driven magma discharge dynamics explain the initially high discharge rates observed during eruptive crises and greatly influence our ability to predict the evolution of effusive eruptions.

  9. Volcano seismicity and ground deformation unveil the gravity-driven magma discharge dynamics of a volcanic eruption.

    PubMed

    Ripepe, Maurizio; Donne, Dario Delle; Genco, Riccardo; Maggio, Giuseppe; Pistolesi, Marco; Marchetti, Emanuele; Lacanna, Giorgio; Ulivieri, Giacomo; Poggi, Pasquale

    2015-01-01

    Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior of the crust to the surface. The eruption is modelled as a gravity-driven drainage of magma stored in the volcanic edifice with a minor contribution of magma supplied at a steady rate from a deep reservoir. Here we show that the discharge rate can be predicted by the contraction of the volcano edifice and that the very-long-period seismicity migrates downwards, tracking the residual volume of magma in the shallow reservoir. Gravity-driven magma discharge dynamics explain the initially high discharge rates observed during eruptive crises and greatly influence our ability to predict the evolution of effusive eruptions. PMID:25980642

  10. Usefulness of rate regulation through continuous ventricular pacing in patients with drug-controlled slower atrial fibrillation and normal or depressed left ventricular systolic function.

    PubMed

    Chiladakis, John; Koutsogiannis, Nikolaos; Kalogeropoulos, Andreas; Zagli, Fani; Arvanitis, Panagiotis; Alexopoulos, Dimitrios

    2008-11-01

    We studied 33 clinically stable patients with permanent atrial fibrillation (AF), implanted with a ventricular demand rate-responsive (VVIR) pacemaker or an automatic defibrillator, in order to evaluate whether continuous right ventricular apex pacing (VP) conferring rate regulation may be advantageous when compared with slower drug-controlled AF. Devices were chronically programmed at ventricular backup pacing. Patients were divided in two groups according to their normal (n = 17) or depressed (n = 16) left ventricular systolic function (LVSF). Ventricular function was studied by using tissue Doppler and color M-mode and echocardiography, as well as B-type natriuretic peptide (BNP) measurements. Baseline data during AF were compared to corresponding measurements following a 1-month pacing period after the devices were programmed at a base rate of 70 beats/min. In both groups, VP worsened some indexes of left and right ventricular function (P < 0.05) without significantly affecting cardiac output, left ventricular filling pressures and BNP (P = not significant). We conclude that VP should not be considered advantageous compared to slower AF.

  11. The 2006 lava dome eruption of Merapi Volcano (Indonesia): Detailed analysis using MODIS TIR

    NASA Astrophysics Data System (ADS)

    Carr, Brett B.; Clarke, Amanda B.; Vanderkluysen, Loÿc

    2016-02-01

    Merapi is one of Indonesia's most active and dangerous volcanoes. Prior to the 2010 VEI 4 eruption, activity at Merapi during the 20th century was characterized by the growth and collapse of a series of lava domes. Periods of very slow growth were punctuated by short episodes of increased eruption rates characterized by dome collapse-generated pyroclastic density currents (PDCs). An eruptive event of this type occurred in May-June, 2006. For effusive eruptions such as this, detailed extrusion rate records are important for understanding the processes driving the eruption and the hazards presented by the eruption. We use thermal infrared (TIR) images from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on NASA's Aqua and Terra satellites to estimate extrusion rates at Merapi Volcano during the 2006 eruption using the method of Harris and Ripepe (2007). We compile a set of 75 nighttime MODIS images of the eruptive period to produce a detailed time series of thermal radiance and extrusion rate that reveal multiple phases of the 2006 eruption. These data closely correspond to the published ground-based observational record and improve observation density and detail during the eruption sequence. Furthermore, additional analysis of radiance values for thermal anomalies in Band 21 (λ = 3.959 μm) of MODIS images results in a new framework for detecting different styles of activity. We successfully discriminate among slow dome growth, rapid dome growth, and PDC-producing dome collapse. We also demonstrate a positive correlation between PDC frequency and extrusion rate, and provide evidence that extrusion rate can increase in response to external events such as dome collapses or tectonic earthquakes. This study represents a new method of documenting volcanic activity that can be applied to other similar volcanic systems.

  12. Can rain cause volcanic eruptions?

    USGS Publications Warehouse

    Mastin, Larry G.

    1993-01-01

    Volcanic eruptions are renowned for their violence and destructive power. This power comes ultimately from the heat and pressure of molten rock and its contained gases. Therefore we rarely consider the possibility that meteoric phenomena, like rainfall, could promote or inhibit their occurrence. Yet from time to time observers have suggested that weather may affect volcanic activity. In the late 1800's, for example, one of the first geologists to visit the island of Hawaii, J.D. Dana, speculated that rainfall influenced the occurrence of eruptions there. In the early 1900's, volcanologists suggested that some eruptions from Mount Lassen, Calif., were caused by the infiltration of snowmelt into the volcano's hot summit. Most such associations have not been provable because of lack of information; others have been dismissed after careful evaluation of the evidence.

  13. Sub-glacial volcanic eruptions

    USGS Publications Warehouse

    White, Donald Edward

    1956-01-01

    The literature on sub-glacial volcanic eruptions and the related flood phenomena has been reviewed as a minor part of the larger problem of convective and conductive heat transfer from intrusive magma. (See Lovering, 1955, for a review of the extensive literature on this subject.) This summary of data on sub-glacial eruptions is part of a program that the U.S. Geological Survey is conducting in connection with its Investigations of Geologic Processes project on behalf of the Division of Research, U.S. Atomic Energy Commission.

  14. Widespread bullous fixed drug eruption

    PubMed Central

    Patell, Rushad D; Dosi, Rupal V; Shah, Purav C; Joshi, Harshal S

    2014-01-01

    A 53-year-old man developed a widespread erythematous eruption which rapidly evolved into fluid-filled bulla mostly involving the distal areas of all four limbs and erosions on the oral as well as anogenital mucosa. Based on clinical presentation, chronology of drug exposure, past events and histopathology as diagnosis of widespread bullous fixed drug eruption was made over Steven Johnson-toxic epidermal necrolysis syndrome. Steroids were deferred and the lesions healed with minimal pigmentation within a week. Differentiating between the two entities has been historically difficult, and yet can have significant therapeutic and prognostic implications. PMID:24510691

  15. Widespread bullous fixed drug eruption.

    PubMed

    Patell, Rushad D; Dosi, Rupal V; Shah, Purav C; Joshi, Harshal S

    2014-02-07

    A 53-year-old man developed a widespread erythematous eruption which rapidly evolved into fluid-filled bulla mostly involving the distal areas of all four limbs and erosions on the oral as well as anogenital mucosa. Based on clinical presentation, chronology of drug exposure, past events and histopathology as diagnosis of widespread bullous fixed drug eruption was made over Steven Johnson-toxic epidermal necrolysis syndrome. Steroids were deferred and the lesions healed with minimal pigmentation within a week. Differentiating between the two entities has been historically difficult, and yet can have significant therapeutic and prognostic implications.

  16. Erupted odontoma: a case report.

    PubMed

    Raval, Nilesh; Mehta, Dhaval; Vachhrajani, Kanan; Nimavat, Abhishek

    2014-07-01

    Odontomas are nonaggressive, hamartomatous developmental malformations or lesions of odontogenic origin, which consist of enamel, dentin, cementum and pulpal tissue 'Erupted odontoma' is a term used to specifically denote odontomas, which are exposed into the oral cavity. These are rare entities with only 25-30 cases being reported so far in the dental literature. Here, we present a rare case of an erupted odontoma in an adolescent patient who came with a complaint of bad aesthetics due to the presence of multiple small teeth like structures in the upper front teeth region.

  17. Chronology, morphology and stratigraphy of pumiceous pyroclastic-flow (ignimbrite) deposits from the eruption of Mount St. Helens on 18 May 1983

    NASA Technical Reports Server (NTRS)

    Criswell, C. W.; Elston, W. E.

    1984-01-01

    Between 1217 and 1620 hours (PDT), on May 18, 1980, the magmatic eruption column of Mount St. Helens formed an ash fountain and pyroclastic flows dominated the eruption process over tephra ejection. Eurption-rate pulsations generally increased to a maximum at 1600 to 1700 hrs. After 1620 hrs, the eruption assumed an open-vent discharge with strong, vertical ejection of tephra. Relative eruption rates (relative mass flux rates) of the pyroclastic flows were determined by correlating sequential photographs and SLAR images, obtained during the eruption, with stratigraphy and surface morphology of the deposits.

  18. Causes and consequences of conduit wall permeability changes during explosive eruptions

    NASA Astrophysics Data System (ADS)

    Rust, Alison; Hanson, Jonathan

    2015-04-01

    Magmatic volatiles, and in some cases external water, drive explosive volcanic eruptions and so the permeability of magma and conduit wall rocks can modulate the style and intensity of eruptions. Both modelling of eruption dynamics and field studies of lithic clasts indicate that fragmentation levels during explosive silicic eruptions commonly reach depths of kilometres. An important consequence is that substantial deviations from lithostatic pressure are sustained in the conduit during eruption, which, according to finite element modelling, are sufficient to damage a substantial volume of rock around the conduit. Underpressured regions will be susceptible to conduit erosion, widening the conduit; field data provide constraints on erosion rates and erosion depths where subsurface stratigraphy is known. Damage to wall rocks will also increase the rock permeability adjacent to the conduit, which could significantly affect magmatic degassing during and between eruptions. The degree to which external water can interact with magma in the conduit will also depend on wall rock permeability and spatial and temporal variations in pressure. When a major magmatic eruption ceases, deep magma is likely to ascend to fill the lower conduit, and the upper conduit may partially collapse forming vertically extensive breccia. Subvolcanic rocks exposed by exploration and mining of porphyry copper deposits (PCDs) and associated alteration and breccias may provide further field constraints on these models. Although syn- and post-mineralization explosive eruptions likely ruin potential PCDs, earlier eruptions might make space for vertical shallow intrusions and help establish permeable regions conducive to focussing of magmatic fluids required for PCD generation.

  19. Dispersal of key subplinian-Plinian tephras from Hekla volcano, Iceland: implications for eruption source parameters

    NASA Astrophysics Data System (ADS)

    Janebo, Maria H.; Thordarson, Thorvaldur; Houghton, Bruce F.; Bonadonna, Costanza; Larsen, Gudrun; Carey, Rebecca J.

    2016-10-01

    Hekla is the most active silicic volcano in Iceland, with 18 subplinian-Plinian eruptions since AD 1104. In the period 1970 to 2000, the frequency of such eruptions increased to once every decade. Hekla is currently inflated to above the levels observed prior to the most recent eruptions in 1991 and 2000. The next eruption could pose a hazard to air traffic between North America and Europe because explosive eruptions of Hekla, independent of size, typically start with a subplinian or Plinian phase that produces a sustained ash plume. We present an overview of five of the largest historical Hekla eruptions (taking place in 1104, 1158, 1300, 1693, and 1766). These eruptions cover a compositional range of rhyolite to andesite, previously estimated Volcanic Explosivity Index (VEI) values of 4-5 and are characterised by contrasting wind dispersal (dispersal axes NW-NE). New isopach maps show both greater deposit thicknesses in the proximal region and wider dispersal than previously inferred, resulting in different volume estimates (minimal values ranging between 0.18 and 0.91 km3). New isopleth maps were also compiled and resulted in inferred plume heights of about 13-25 km. These changes in the estimated values of volume and mass eruption rates have large implications on the forecasting and impacts of future Hekla eruptions.

  20. Questions Concerning the Disconnection and Eruption of Filaments and CMEs

    NASA Technical Reports Server (NTRS)

    Kucera, Theresa

    2007-01-01

    Reviews examples of eruptions and failed eruptions of filaments and CMEs and review questions concerning the processes and mechanisms involved. Where and how does disconnection occur? What can we learn (if anything!) about CME eruptions by observing related filament eruptions?

  1. A MODEL FOR MAGNETICALLY COUPLED SYMPATHETIC ERUPTIONS

    SciTech Connect

    Toeroek, T.; Titov, V. S.; Mikic, Z.; Linker, J. A.; Panasenco, O.; Reeves, K. K.; Velli, M.; De Toma, G.

    2011-10-01

    Sympathetic eruptions on the Sun have been observed for several decades, but the mechanisms by which one eruption can trigger another remain poorly understood. We present a three-dimensional MHD simulation that suggests two possible magnetic trigger mechanisms for sympathetic eruptions. We consider a configuration that contains two coronal flux ropes located within a pseudo-streamer and one rope located next to it. A sequence of eruptions is initiated by triggering the eruption of the flux rope next to the streamer. The expansion of the rope leads to two consecutive reconnection events, each of which triggers the eruption of a flux rope by removing a sufficient amount of overlying flux. The simulation qualitatively reproduces important aspects of the global sympathetic event on 2010 August 1 and provides a scenario for the so-called twin filament eruptions. The suggested mechanisms are also applicable for sympathetic eruptions occurring in other magnetic configurations.

  2. A Model for Magnetically Coupled Sympathetic Eruptions

    NASA Technical Reports Server (NTRS)

    Torok, T.; Panasenco, O.; Titrov, V. S.; Mikic, Z.; Reeves, K. K.; Velli, M.; Linker, J. A.; DeToma, G.

    2011-01-01

    Sympathetic eruptions on the Sun have been observed for several decades, but the mechanisms by which one eruption can trigger another remain poorly understood. We present a three-dimenSional MHD simulation that suggests two possible magnetic trigger mechanisms for sympathetic eruptions. We consider a configuration that contains two coronal flux ropes located within a pseudo-streamer and one rope located next to it. A sequence of eruptions is initiated by triggering the eruption of the flux rope next to the streamer. The expansion of the rope leads to two consecutive reconnection events, each of which triggers the eruption of a flux rope by removing a sufficient amount of overlying flux. The simulation qualitatively reproduces important aspects of the global sympathetic event on 2010 August 1 and provides a scenario for the so-called twin filament eruptions. The suggested mechanisms are also applicable for sympathetic eruptions occurring in other magnetic configurations.

  3. Eruption cysts: A series of two cases

    PubMed Central

    Dhawan, Preeti; Kochhar, Gulsheen Kaur; Chachra, Sanjay; Advani, Shweta

    2012-01-01

    Eruption cysts are benign cysts that appear on the mucosa of a tooth shortly before its eruption. They may disappear by themselves but if they hurt, bleed or are infected they may require surgical treatment to expose the tooth and drain the contents. Here we present 2 case reports of eruption cysts presenting with different chief complaint. The treatment included incising the eruption cyst and draining the contents of the cyst. PMID:23559935

  4. Summertime actinic lichenoid eruption (lichen planus actinicus).

    PubMed

    Isaacson, D; Turner, M L; Elgart, M L

    1981-04-01

    A patient with an unusual lichenoid photosensitive eruption is presented. The features differentiating this entity from classic lichen planus, lupus erythematosus, and polymorphous light eruption are discussed. Phototesting confirmed the provocative influence of sunlight. We prefer the name "summertime actinic lichenoid eruption" to that of "lichen planus subtropicus" or "lichen planus actinicus," since this condition is not confined to subtropical countries, and, although light appears to initiate the eruption, its exact relationship to lichen planus is unclear.

  5. Recent progress in understanding the eruptions of classical novae

    NASA Technical Reports Server (NTRS)

    Shara, Michael M.

    1988-01-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  6. Recent progress in understanding the eruptions of classical novae

    SciTech Connect

    Shara, M.M.

    1988-10-01

    Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

  7. Suspected drug eruption in seven dogs during administration of flucytosine.

    PubMed

    Malik, R; Medeiros, C; Wigney, D I; Love, D N

    1996-10-01

    7 of 8 dogs receiving combination drug therapy consisting of flucytosine together with amphotericin B and/or a triazole for cryptococcosis or aspergillosis developed cutaneous or mucocutaneous eruptions during the course of treatment. Lesions resolved in all cases following discontinuation of flucytosine despite continued administration of other antifungals, suggesting the eruption was referable primarily to the flucytosine component of therapy. Lesions developed 13 to 41 days (median 20 days) after commencing flucytosine (105 to 188 mg/kg/day divided and given every 8 h; median dose rate 150 mg/kg/day). The cumulative dose of flucytosine given prior to the first signs of the drug eruption ranged from 1.7 to 6.8 g/kg (median 2.3 g/kg). The eruptions consisted of depigmentation, followed by ulceration, exudation and crust formation. The scrotum was affected in all 4 male dogs, the nasal plane in 6 of 7 cases, while the lips, vulva, external ear canal and integument were involved in a smaller number of cases. There was considerable variation in the severity of lesions, with changes being most marked when flucytosine was continued for several days after lesions first appeared. Some dogs experienced malaise and inappetence in association with the suspected drug eruption. Healing took a variable period, typically in excess of 2 weeks after discontinuing flucytosine, with up to 2 months being required for total resolution of the lesions. All lesions resolved eventually without scarring or permanent loss of pigment. PMID:8937669

  8. Long-range infrasound monitoring of eruptive volcanoes.

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Innocenti, Lorenzo; Ulivieri, Giacomo; Lacanna, Giorgio; Ripepe, Maurizio

    2016-04-01

    The efficient long-range propagation in the atmosphere makes infrasound of active volcanoes extremely promising and opens new perspectives for volcano monitoring at large scale. In favourable propagation conditions, long-range infrasound observations can be used to track the occurrence and the duration of volcanic eruptions also at remote non-monitored volcanoes, but its potential to infer volcanic eruptive source term is still debated. We present results of comparing five years of infrasound of eruptive activity at Mt.Etna volcano (Italy) recorded both at local (~5 km) and at regional distances (~600 km) from the source. Infrasound of lava fountains at Etna volcano, occurring in between 2010 and 2015, are analysed in terms of the local and regional wavefield record, and by comparing to all available volcanic source terms (i.e. plume height and mass eruption rates). Besides, the potential of near real-time notification of ongoing volcanic activity at Etna volcano at a regional scale is investigated. In particular we show how long range infrasound, in the case of Etna volcano, can be used to promptly deliver eruption notification and reliability is constrained by the results of the local array. This work is performed in the framework of the H2020 ARISE2 project funded by the EU in the period 2015-2018.

  9. Direct video and hydrophone observations of submarine explosive eruptions at NW Rota-1 volcano, Mariana arc

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Cashman, K. V.; Embley, R. W.; Matsumoto, H.; Dziak, R. P.; de Ronde, C. E. J.; Lau, T. K.; Deardorff, N. D.; Merle, S. G.

    2008-08-01

    Extraordinary video and hydrophone observations of a submarine explosive eruption were made with a remotely operated vehicle in April 2006 at a depth of 550-560 m on NW Rota-1 volcano in the Mariana arc. The observed eruption evolved from effusive to explosive, while the eruption rate increased from near zero to 10-100 m3/h. During the peak in activity, cyclic explosive bursts 2-6 min long were separated by shorter non-eruptive pauses lasting 10-100 s. The size of the ejecta increased with the vigor of the explosions. A portable hydrophone deployed near the vent recorded sounds correlated with the explosive bursts; the highest amplitudes were ˜50 dB higher than ambient noise at frequencies between 10 and 50 Hz. The acoustic data allow us to quantify the durations, amplitudes, and evolution of the eruptive events over time. The low eruption rate, high gas/lava ratio, and rhythmic eruptive behavior at NW Rota-1 are most consistent with a Strombolian eruptive style. We interpret that the eruption was primarily driven by the venting of magmatic gases, which was also the primary source of the sound recorded during the explosive bursts. The rhythmic nature of the bursts can be explained by partial gas segregation in the conduit and upward migration in a transitional regime between bubbly flow and fully developed slug flow. The strongest explosive bursts were accompanied by flashes of red glow and oscillating eruption plumes in the vent, apparently caused by magma-seawater interaction and rapid steam formation and condensation. This is the first time submarine explosive eruptions have been witnessed with simultaneous near-field acoustic recordings.

  10. The June 2014 eruption at Piton de la Fournaise: Robust methods developed for monitoring challenging eruptive processes

    NASA Astrophysics Data System (ADS)

    Villeneuve, N.; Ferrazzini, V.; Di Muro, A.; Peltier, A.; Beauducel, F.; Roult, G. C.; Lecocq, T.; Brenguier, F.; Vlastelic, I.; Gurioli, L.; Guyard, S.; Catry, T.; Froger, J. L.; Coppola, D.; Harris, A. J. L.; Favalli, M.; Aiuppa, A.; Liuzzo, M.; Giudice, G.; Boissier, P.; Brunet, C.; Catherine, P.; Fontaine, F. J.; Henriette, L.; Lauret, F.; Riviere, A.; Kowalski, P.

    2014-12-01

    After almost 3.5 years of quiescence, Piton de la Fournaise (PdF) produced a small summit eruption on 20 June 2014 at 21:35 (GMT). The eruption lasted 20 hours and was preceded by: i) onset of deep eccentric seismicity (15-20 km bsl; 9 km NW of the volcano summit) in March and April 2014; ii) enhanced CO2 soil flux along the NW rift zone; iii) increase in the number and energy of shallow (<1.5 km asl) VT events. The increase in VT events occurred on 9 June. Their signature, and shallow location, was not characteristic of an eruptive crisis. However, at 20:06 on 20/06 their character changed. This was 74 minutes before the onset of tremor. Deformations then began at 20:20. Since 2007, PdF has emitted small magma volumes (<3 Mm3) in events preceded by weak and short precursory phases. To respond to this challenging activity style, new monitoring methods were deployed at OVPF. While the JERK and MSNoise methods were developed for processing of seismic data, borehole tiltmeters and permanent monitoring of summit gas emissions, plus CO2 soil flux, were used to track precursory activity. JERK, based on an analysis of the acceleration slope of a broad-band seismometer data, allowed advanced notice of the new eruption by 50 minutes. MSNoise, based on seismic velocity determination, showed a significant decrease 7 days before the eruption. These signals were coupled with change in summit fumarole composition. Remote sensing allowed the following syn-eruptive observations: - INSAR confirmed measurements made by the OVPF geodetic network, showing that deformation was localized around the eruptive fissures; - A SPOT5 image acquired at 05:41 on 21/06 allowed definition of the flow field area (194 500 m2); - A MODIS image acquired at 06:35 on 21/06 gave a lava discharge rate of 6.9±2.8 m3 s-1, giving an erupted volume of 0.3 and 0.4 Mm3. - This rate was used with the DOWNFLOW and FLOWGO models, calibrated with the textural data from Piton's 2010 lava, to run lava flow

  11. Prospects for eruption prediction in near real-time

    USGS Publications Warehouse

    Voight, B.; Cornelius, R.R.

    1991-01-01

    THE 'materials science' method for eruption prediction1-3 arises from the application of a general law governing the failure of materials: ??-?? ??-A=0, where A and ?? are empirical constants, and ?? is an observable quantity such as ground deformation, seismicity or gas emission. This law leads to the idea of the 'inverse-rate' plot, in which the time of failure can be estimated by extrapolation of the curve of ??-1 versus time to a pre-deter-mined intercept. Here we suggest that this method can be combined with real-time seismic amplitude monitoring to provide a tool for near-real-time eruption prediction, and we demonstrate how it might have been used to predict two dome-growth episodes at Mount St Helens volcano in 1985 and 1986, and two explosive eruptions at Redoubt volcano in 1989-90.

  12. Sorafenib induced eruptive melanocytic lesions.

    PubMed

    Uhlenhake, Elizabeth E; Watson, Alice C; Aronson, Peter

    2013-05-01

    Sorafenib is a multikinase inhibitor FDA-approved for the treatment of advanced renal cell and hepatocellular carcinoma. Dermatologic side effects include hand-foot skin reaction, facial and scalp erythema and desquamation, splinter subungual hemorrhages, alopecia, pruritus, xerosis, keratoacanthomas, and squamous cell carcinomas. We report sudden eruption of melanocytic nevi diffusely in a patient receiving sorafenib. PMID:24011281

  13. Building the Volcanic Oceanic Crust One Eruption at a Time (Invited)

    NASA Astrophysics Data System (ADS)

    Sinton, J. M.; Rubin, K. H.; White, S. M.; Colman, A.; Bowles, J. A.; Gronvold, K.

    2010-12-01

    The physical and chemical characteristics of lava flow fields formed during individual volcanic eruptions provides critical information on the nature of underlying magma reservoirs and the diking events that feed magma to the surface. Chemical variability of individual flow fields can constrain important parameters, such as the depth, geometry, melt percentage, and cooling rate of magma reservoirs and, in some case, whether or not dikes traveled vertically from magma reservoirs to the surface, with examples from the East Pacific Rise, Juan de Fuca Ridge and Iceland. Lava flow morphology and the length of ridge activated during individual eruptions constrain eruption rates and, in some cases, how eruption rates and magma sources vary during the course of long-lived eruptions. Although the study of submarine volcanic eruptions has historically been dominated by study of very recent flow fields or remotely detected “events”, a recent cruise to the Galápagos Spreading Center demonstrated that volcanic geology can be deciphered for areas of seafloor using the same basic methods commonly employed on-land: near-bottom geological observations, remote images at the appropriate spatial resolution, and petrologic and geochronologic study of samples. For the Galápagos study we used the AUV Sentry to obtain very high resolution (~1-m spatial scale) bathymetry, 26 Alvin dives, 17 camera-tows, and on-shore chemical and magnetic paeleointensity sample analyses to identify the areal extents, chemical variability and age constraints of at least 14 previously unknown discrete eruptive units in two areas with highly contrasting average magma supply defined by variations in crustal thickness and spreading rate. Preliminary general results of this study indicate that, at high magma supply, relatively low-volume eruptions are fed from shallow, moderately to highly differentiated, melt-dominated magma chambers to elongate fissures at relatively high average eruption rates. At low

  14. Aurorae and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  15. Aurorae and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  16. Eruption and emplacement timescales of ignimbrite super-eruptions from thermo-kinetics of glass shards

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Wadsworth, Fabian; Vasseur, Jérémie; Russell, James; Andrews, Graham; Hess, Kai-Uwe; von Aulock, Felix; Kendrick, Jackie; Tuffen, Hugh; Biggin, Andy; Dingwell, Donald

    2015-02-01

    Super-eruptions generating hundreds of cubic kilometres of pyroclastic density currents are commonly recorded by thick, welded and lava-like ignimbrites. Despite the huge environmental impact inferred for this type of eruption, little is yet known about the timescales of deposition and post-depositional flow. Without these timescales, the critical question of the duration of any environmental impact, and the ensuing gravity of its effects for the Earth system, eludes us. The eruption and welding of ignimbrites requires three transects of the glass transition. Magma needs to: 1) fragment during ascent, 2) liquefy and relax during deposition, agglutination and welding (sintering), and 3) quench by cooling into the glassy state. Here we show that welding is a rapid, syn-depositional process and that the welded ignimbrite sheet may flow for up to a few hours before passing through the glass transition a final time. Geospeedometry reveals that the basal vitrophyre of the Grey’s Landing ignimbrite underwent the glass transition at a rate of ~0.1 °C.min^-1 at 870 °C; that is, 30-180 °C below pre-eruptive geothermometric estimates. Application of a 1-D cooling model constrains the timescale of deposition, agglutination, and welding of the basal vitrophyre to less than 1 hour, and possibly even tens of minutes. Thermo-mechanical iteration of the sintering process indicates an optimal temperature solution for the emplacement of the vitrophyres at 966 °C. The vitrophyres reveal a Newtonian rheology up to 46 MPa, which suggests that the ash particles annealed entirely during welding and that viscous energy dissipation is unlikely from loading conditions alone, unless shear stresses imposed by the overlying ash flow were excessively high and sustained over long distances. The findings underline the value of the term 'lava-like' flow to describe the end rheology of Snake River-type ignimbrites, fully consistent with the typical lithofacies observed.

  17. Most Powerful Eruption in the Universe Discovered

    NASA Astrophysics Data System (ADS)

    2005-01-01

    Astronomers have found the most powerful eruption seen in the Universe using NASA's Chandra X-ray Observatory. A supermassive black hole generated this eruption by growing at a remarkable rate. This discovery shows the enormous appetite of large black holes, and the profound impact they have on their surroundings. The huge eruption is seen in a Chandra image of the hot, X-ray emitting gas of a galaxy cluster called MS 0735.6+7421. Two vast cavities extend away from the supermassive black hole in the cluster's central galaxy. The eruption - which has lasted for 100 million years and is still going - has generated the energy equivalent to hundreds of millions of gamma-ray bursts. Animation of Eruption from Supermassive Black Hole Animation of Eruption from Supermassive Black Hole This event was caused by gravitational energy release as enormous amounts of matter fell toward a black hole. Most of the matter was swallowed, but some of it was violently ejected before being captured by the black hole. "I was stunned to find that a mass of about 300 million Suns was swallowed," said Brian McNamara of Ohio University in Athens, lead author of the study that appears in the January 6, 2005 issue of Nature. "This is almost as massive as the supermassive black hole that swallowed it." Astronomers are not sure where such large amounts of matter came from. One theory is that gas from the host galaxy catastrophically cooled and was then swallowed by the black hole. Illustration of MS 0735.6+742 Illustration of MS 0735.6+742 The energy released shows that the black hole in MS 0735 has grown very dramatically during this eruption. Previous studies suggest that other large black holes have grown very little in the recent past, and that only smaller black holes are still growing quickly. "This new result is as surprising as it is exciting", said co-author Paul Nulsen of the Harvard-Smithsonian Center of Astrophysics. "This black hole is feasting when it should be fasting." Radio

  18. Preliminary Spreadsheet of Eruption Source Parameters for Volcanoes of the World

    USGS Publications Warehouse

    Mastin, Larry G.; Guffanti, Marianne; Ewert, John W.; Spiegel, Jessica

    2009-01-01

    Volcanic eruptions that spew tephra into the atmosphere pose a hazard to jet aircraft. For this reason, the International Civil Aviation Organization (ICAO) has designated nine Volcanic Ash and Aviation Centers (VAACs) around the world whose purpose is to track ash clouds from eruptions and notify aircraft so that they may avoid these ash clouds. During eruptions, VAACs and their collaborators run volcanic-ashtransport- and-dispersion (VATD) models that forecast the location and movement of ash clouds. These models require as input parameters the plume height H, the mass-eruption rate , duration D, erupted volume V (in cubic kilometers of bubble-free or 'dense rock equivalent' [DRE] magma), and the mass fraction of erupted tephra with a particle size smaller than 63 um (m63). Some parameters, such as mass-eruption rate and mass fraction of fine debris, are not obtainable by direct observation; others, such as plume height or duration, are obtainable from observations but may be unavailable in the early hours of an eruption when VATD models are being initiated. For this reason, ash-cloud modelers need to have at their disposal source parameters for a particular volcano that are based on its recent eruptive history and represent the most likely anticipated eruption. They also need source parameters that encompass the range of uncertainty in eruption size or characteristics. In spring of 2007, a workshop was held at the U.S. Geological Survey (USGS) Cascades Volcano Observatory to derive a protocol for assigning eruption source parameters to ash-cloud models during eruptions. The protocol derived from this effort was published by Mastin and others (in press), along with a world map displaying the assigned eruption type for each of the world's volcanoes. Their report, however, did not include the assigned eruption types in tabular form. Therefore, this Open-File Report presents that table in the form of an Excel spreadsheet. These assignments are preliminary and will

  19. A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions

    NASA Astrophysics Data System (ADS)

    Mastin, L. G.; Guffanti, M.; Servranckx, R.; Webley, P.; Barsotti, S.; Dean, K.; Durant, A.; Ewert, J. W.; Neri, A.; Rose, W. I.; Schneider, D.; Siebert, L.; Stunder, B.; Swanson, G.; Tupper, A.; Volentik, A.; Waythomas, C. F.

    2009-09-01

    During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days in order to define hazards to aircraft and to communities downwind. Those models use input parameters, called "eruption source parameters", such as plume height H, mass eruption rate Ṁ, duration D, and the mass fraction m63 of erupted debris finer than about 4ϕ or 63 μm, which can remain in the cloud for many hours or days. Observational constraints on the value of such parameters are frequently unavailable in the first minutes or hours after an eruption is detected. Moreover, observed plume height may change during an eruption, requiring rapid assignment of new parameters. This paper reports on a group effort to improve the accuracy of source parameters used by VATDs in the early hours of an eruption. We do so by first compiling a list of eruptions for which these parameters are well constrained, and then using these data to review and update previously studied parameter relationships. We find that the existing scatter in plots of H versus Ṁ yields an uncertainty within the 50% confidence interval of plus or minus a factor of four in eruption rate for a given plume height. This scatter is not clearly attributable to biases in measurement techniques or to well-recognized processes such as elutriation from pyroclastic flows. Sparse data on total grain-size distribution suggest that the mass fraction of fine debris m63 could vary by nearly two orders of magnitude between small basaltic eruptions (˜ 0.01) and large silicic ones (> 0.5). We classify eleven eruption types; four types each for different sizes of silicic and mafic eruptions; submarine eruptions; "brief" or Vulcanian eruptions; and eruptions that generate co-ignimbrite or co-pyroclastic flow plumes. For each eruption type we assign source parameters. We then assign a characteristic eruption type to each of the world's ˜ 1500 Holocene

  20. A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions

    USGS Publications Warehouse

    Mastin, L.G.; Guffanti, M.; Servranckx, R.; Webley, P.; Barsotti, S.; Dean, K.; Durant, A.; Ewert, J.W.; Neri, A.; Rose, William I.; Schneider, D.; Siebert, L.; Stunder, B.; Swanson, G.; Tupper, A.; Volentik, A.; Waythomas, C.F.

    2009-01-01

    During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days in order to define hazards to aircraft and to communities downwind. Those models use input parameters, called "eruption source parameters", such as plume height H, mass eruption rate ???, duration D, and the mass fraction m63 of erupted debris finer than about 4??{symbol} or 63????m, which can remain in the cloud for many hours or days. Observational constraints on the value of such parameters are frequently unavailable in the first minutes or hours after an eruption is detected. Moreover, observed plume height may change during an eruption, requiring rapid assignment of new parameters. This paper reports on a group effort to improve the accuracy of source parameters used by VATDs in the early hours of an eruption. We do so by first compiling a list of eruptions for which these parameters are well constrained, and then using these data to review and update previously studied parameter relationships. We find that the existing scatter in plots of H versus ??? yields an uncertainty within the 50% confidence interval of plus or minus a factor of four in eruption rate for a given plume height. This scatter is not clearly attributable to biases in measurement techniques or to well-recognized processes such as elutriation from pyroclastic flows. Sparse data on total grain-size distribution suggest that the mass fraction of fine debris m63 could vary by nearly two orders of magnitude between small basaltic eruptions (??? 0.01) and large silicic ones (> 0.5). We classify eleven eruption types; four types each for different sizes of silicic and mafic eruptions; submarine eruptions; "brief" or Vulcanian eruptions; and eruptions that generate co-ignimbrite or co-pyroclastic flow plumes. For each eruption type we assign source parameters. We then assign a characteristic eruption type to each of the world's ??? 1500

  1. Mortality rates or sociomedical indicators? The work of the League of Nations on standardizing the effects of the Great Depression on health.

    PubMed

    Garcia, Monica

    2014-01-01

    This article explores the first international effort by the League of Nations Health Organization (LNHO) to standardize the study of the effects of the economic crisis of the 1930s on health. Instead of analysing this effort with the benefit of hindsight, this article takes into account the actors' perspectives and, therefore, it relies on the documents produced by the LNHO and public health experts of the 1930s, as well as on the historical scholarship on this subject. This article shows that, despite the declining death rates in Europe and in the US during the crisis, the LNHO considered that death rates concealed a more subtle effect of the crisis on health; hence, they launched a project aimed at making the effect visible. It describes the LNHO programme and the guidelines and methods set out by the organization in 1932 to observe this subtle effect through sociomedical investigations. The results of these surveys are summarized and the article discusses how the eugenic arguments used to explain them were not accepted by the LNHO. The article also shows how some members of the LNHO considered the results of the sociomedical surveys inconclusive and questioned the usefulness of socioeconomic indicators; in so doing, they raised concerns about the intervention of the LNHO in national matters and about the risks of crossing the established limits between science and politics. This article shows that an historical analysis, which takes into account the points of view of the actors involved, illuminates the factors that led the LNHO to conclude that mortality rates were the best method for measuring the effects of the economic crisis on health and that, as they were declining, the Great Depression was not having any deleterious effect on public health. PMID:23132917

  2. Gender Differences in Rates of Depressive Symptoms among Low-Income, Urban, African American Youth: A Test of Two Mediational Hypotheses

    ERIC Educational Resources Information Center

    Grant, Kathryn E.; Lyons, Aoife L.; Finkelstein, Jo-Ann S.; Conway, Kathryn M.; Reynolds, Linda K.; O'Koon, Jeffrey H.; Waitkoff, Gregory R.; Hicks, Kira J.

    2004-01-01

    The present study tested for gender differences in depressive symptoms in a sample of 622 low-income, urban, African American adolescents. Results indicate that adolescent girls in this sample were significantly more likely to endorse depressive symptoms than were boys. To examine possible explanations for this gender difference, 2 variables were…

  3. Detecting Depression in Elderly Medical Inpatients.

    ERIC Educational Resources Information Center

    Rapp, Stephen R.; And Others

    1988-01-01

    Used Research Diagnostic Criteria to assess base rate of detection of depression in 150 elderly medical inpatients by nonpsychiatric physicians, and evaluated psychometric properties of screening instruments to assess depression. Found detection of depression by house staff extremely low (8.7 percent). Beck Depression Inventory (BDI), BDI…

  4. Tinnitus severity, loudness, and depression.

    PubMed

    Folmer, R L; Griest, S E; Meikle, M B; Martin, W H

    1999-07-01

    Answers to questionnaires filled out by 436 patients who visited our tinnitus clinic were analyzed. Patients were asked to report the presence or absence of depression and to rate the loudness and severity of their tinnitus. Responses to questions about tinnitus loudness and severity from 121 patients who reported current depression were compared with responses from 285 patients who reported no history of depression. There was no significant difference in reported loudness of tinnitus between patients with and without depression. However, patients with current depression scored significantly higher than patients without depression on all 12 questions relating to tinnitus severity. We conclude that depression and tinnitus severity are linked in some patients. Treatment of depression with medications and psychotherapy is likely to reduce tinnitus severity for many of these patients. PMID:10388877

  5. [Disproportionate eruption of maxillary and mandibular incisors in the long-tailed ground squirrel].

    PubMed

    Klevezal', G A; Potapova, E G

    2010-01-01

    Abstract-The surface of the maxillary and mandibular incisors of Spermophilus undulatus long-tailed ground squirrels, including those born in the current year and those that have hibernated (trapped one month or later after hibernation) is studied. The presence of daily growth on the incisors' surface allows the evaluation of their eruption rate; a specific change in the character of the incisors' eruption corresponds to winter hibernation (hibernation zone), which serves as the time mark. Correlation between the eruption rates of the maxillary and mandibular incisors typical for rodents is found in yearlings and some animals after hibernation. The eruption rate of the mandibular incisors is higher than the eruption rate of the maxillary incisors and can be taken as proportional to their length. In individuals that have hibernated and show proportional eruption of the incisors, the proportion of the total length of the incisor formed before and after hibernation is equal for the maxillary and mandibular incisors. In the individuals that have hibernated and show the correlation of the total length of the maxillary and mandibular incisors typical for rodents, the eruption rate of the mandibular incisor is equal to or less than the eruption rate of the maxillary incisor and the proportion of the incisor formed before hibernation is greater in the mandibular incisor than in the maxillary. This disproportionate pattern of incisor eruption is not typical for rodents and is a result of inequal grinding of the maxillary and mandibular incisors, which ultimately results in the normal ratio of the total length of the maxillary and mandibular incisors.

  6. Teen Depression

    MedlinePlus

    ... shown that certain types of talk therapy or psychotherapy can help teens deal with depression. These include ... behaviors, and feelings related to depression, and interpersonal psychotherapy, which focuses on working on relationships. Read more ...

  7. Postpartum Depression

    MedlinePlus

    ... do not need treatment. The symptoms of postpartum depression last longer and are more severe. You may ... treatment right away, often in the hospital. Postpartum depression can begin anytime within the first year after ...

  8. A study of eruptive solar events with negative radio bursts

    NASA Astrophysics Data System (ADS)

    Kuz'menko, I. V.; Grechnev, V. V.; Uralov, A. M.

    2009-11-01

    Solar events of June 15/16, 2000, June 1/2, 2002, February 6, 2002, and February 7, 2002, have been studied. These events probably belong to a poorly studied class of explosive eruptions. In such events disintegration of the magnetic structure of an eruptive filament and dispersing of its fragments as a cloud over a considerable part of the solar surface are possible. The analysis of SOHO/EIT extreme ultraviolet images obtained in the 195 Å and 304 Å channels has revealed the appearance of dimmings of various shapes and propagation of a coronal wave for June 1/2, 2002. In all the events the Nobeyama, Learmonth, and Ussuriysk observatories recorded negative radio bursts at several frequencies in the 1-10 GHz range. Most likely, these bursts were due to absorption of solar radio emission in clouds produced by fragments of filaments. Absorption of the solar background radiation can be observed as a depression of the emission in the 304 Å channel. A model has been developed, which permits one to estimate parameters of absorbing plasma such as temperature, optical thickness, area of the absorbing cloud, and its height above the chromosphere from the radio absorption observed at several frequencies. The obtained values of the temperature, 8000-9000 K, demonstrate that the absorber was the material of an erupted cool filament. The model estimate of the masses of the ejecta in the considered events were ˜1015 g, which is comparable to masses of typical filaments and coronal mass ejections.

  9. A tale of two seafloor eruptions: Comparing seismic data from the 2006 East Pacific Rise and 2015 Axial Seamount eruptions

    NASA Astrophysics Data System (ADS)

    Tolstoy, M.; Wilcock, W. S. D.; Tan, Y. J.; Waldhauser, F.

    2015-12-01

    In January 2006 at 9°50'N on the East Pacific Rise, a three-OBS array captured the first in situ seismic data from a mid-ocean ridge eruption. The data show a steady build up in seismicity over the preceding 2+ years leading to a seismic crisis on January 22nd2006 that lasted approximately 6 hours, with one particularly intense hour interpreted as a rising dike (Tolstoy et al., 2006). This was followed by approximately 10 days of dwindling activity. In April-May 2015, at the ridge-hotspot Axial Seamount, an eight-OBS array captured the second in situ seismic data, and first real-time data, from a mid-ocean ridge eruption. This eruption was also preceded by high seismicity rates, though data were only available for ~6 months prior to the eruption. An ~10 hr seismic crisis on April 24thwas followed by almost a month of dwindling activity. Immediately following the end of the crisis, previously unknown impulsive waterborne signals were observed coming from two sites along the north rift of Axial Seamount (Wilcock et al., this meeting; Garcia et al., this meeting). The signals were interpreted as being associated with lava reaching the seafloor, and subsequent multibeam mapping and an ROV dive confirmed the presence of fresh lava at these sites (Kelley et al., this meeting). Re-examination of the East Pacific Rise eruption data has shown that the same impulsive waterborne signals were also observed there starting ~3 hrs after the beginning of the 2006 seismic crisis (Tan et al., this meeting). The locations of these signals track the mapped lava flow associated with this eruption (Soule et al., 2007), further supporting their association with lava extrusion onto the seafloor. These two eruptions show similar characteristics including ~6-10 hr seismic crises, and lava likely reaching the surface within ~3 hrs (EPR) and ~10 hrs (Axial) of the initiation of seismic crisis activity. They also show similar tremor activity, likely suggesting similar magma movement processes

  10. A statistical method linking geological and historical eruption time series for volcanic hazard estimations: Applications to active polygenetic volcanoes

    NASA Astrophysics Data System (ADS)

    Mendoza-Rosas, Ana Teresa; De la Cruz-Reyna, Servando

    2008-09-01

    The probabilistic analysis of volcanic eruption time series is an essential step for the assessment of volcanic hazard and risk. Such series describe complex processes involving different types of eruptions over different time scales. A statistical method linking geological and historical eruption time series is proposed for calculating the probabilities of future eruptions. The first step of the analysis is to characterize the eruptions by their magnitudes. As is the case in most natural phenomena, lower magnitude events are more frequent, and the behavior of the eruption series may be biased by such events. On the other hand, eruptive series are commonly studied using conventional statistics and treated as homogeneous Poisson processes. However, time-dependent series, or sequences including rare or extreme events, represented by very few data of large eruptions require special methods of analysis, such as the extreme-value theory applied to non-homogeneous Poisson processes. Here we propose a general methodology for analyzing such processes attempting to obtain better estimates of the volcanic hazard. This is done in three steps: Firstly, the historical eruptive series is complemented with the available geological eruption data. The linking of these series is done assuming an inverse relationship between the eruption magnitudes and the occurrence rate of each magnitude class. Secondly, we perform a Weibull analysis of the distribution of repose time between successive eruptions. Thirdly, the linked eruption series are analyzed as a non-homogeneous Poisson process with a generalized Pareto distribution as intensity function. As an application, the method is tested on the eruption series of five active polygenetic Mexican volcanoes: Colima, Citlaltépetl, Nevado de Toluca, Popocatépetl and El Chichón, to obtain hazard estimates.

  11. SYMPATHETIC FILAMENT ERUPTIONS CONNECTED BY CORONAL DIMMINGS

    SciTech Connect

    Jiang Yunchun; Yang Jiayan; Hong Junchao; Bi Yi; Zheng Ruisheng

    2011-09-10

    We present for the first time detailed observations of three successive, interdependent filament eruptions that occurred one by one within 5 hr from different locations beyond the range of a single active region. The first eruption was observed from an active region and was associated with a coronal mass ejection (CME), during which diffuse and complex coronal dimmings formed, largely extending to the two other filaments located in quiet-Sun regions. Then, both quiescent filaments consecutively underwent the second and third eruptions, while the nearby dimmings were persistent. Comparing the result of a derived coronal magnetic configuration, the magnetic connectivity between the dimmings suggested that they were caused by the joint effect of simple expansion of overlying loop systems forced by the first eruption, as well as by its erupting field interacting or reconnecting with the surrounding magnetic structures. Note that the dimming process in the first eruption indicated a weakening and partial removal of an overlying magnetic field constraint on the two other filaments, and thus one can physically connect these eruptions as sympathetic. It appears that the peculiar magnetic field configuration in our event was largely favorable to the occurrence of sympathetic filament eruptions. Because coronal dimmings are frequent and common phenomena in solar eruptions, especially in CME events, it is very likely that they represent a universal agent that can link consecutive eruptions nearby with sympathetic eruptions.

  12. Gas-Driven Eruptions, and Speculation for Methane-Driven Ocean Eruptions

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2001-12-01

    Brad Sturtevant was a central player in experimental simulations of various types of eruptions, including those driven by the exsolution of gas initially dissolved in a liquid (referred to as gas-driven eruptions, including explosive volcanic eruptions, lake eruptions and eruption of Champagne), and those driven by the evaporation of a liquid (such as geyser eruption, or evaporation waves). The experimental simulations helped to bring together the general understanding of different eruptions. Among gas-driven eruptions, explosive volcanic eruptions are the most familiar and spectacular type. Lake eruptions were recognized only in the 1980's. The underlying principles of the two types of eruptions are similar although there are some difference in the role of the conduit and buoyancy. The main purpose of this report is to speculate on a possible but yet unrecognized type of gas-driven eruptions, methane-driven water eruptions in oceans. In marine sediment, huge amount of CH4 is stored either as gas or as methane hydrate. (The gas pockets might burst, resulting in mud "volcanos".) Under some unusual circumstances such as marine landslides or earthquakes, a large amount of CH4 may be released from sediment to seawater. Depending on the local pressure-temperature conditions, and depending on the kinetics of the various chemical reactions, the released methane gas might lead to gas-driven explosive eruptions. This type of eruptions would be similar to CO2-driven lake eruptions, except that the gas is CH4 instead of CO2. Although no such eruptions have been reported and they are expected to be rare, theoretically they are possible. Because CH4 gas is less dense than air, erupted CH4 gas cloud is expected to rise high into the atmosphere instead of forming ground-hugging flows for CO2 gas flows. Hence the danger to life on the ground is smaller. Satellite imaging might be able to detect such eruptions.

  13. Eruptive outflow phases of massive stars

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    2011-07-01

    I review recent progress on understanding eruptions of unstable massive stars, with particular attention to the diversity of observed behavior in extragalatic optical transient sources that are generally associated with giant eruptions of luminous blue variables (LBVs). These eruptions are thought to represent key mass loss episodes in the lives of massive stars. I discuss the possibility of dormant LBVs and implications for the duration of the greater LBV phase and its role in stellar evolution. These eruptive variables show a wide range of peak luminosity, decay time, expansion speeds, and progenitor luminosity, and in some cases they have been observed to suffer multiple eruptions. This broadens our view of massive star eruptions compared to prototypical sources like Eta Carinae, and provides important clues for the nature of the outbursts. I will also review and discuss some implications about the possible physical mechanisms involved, although the cause of the eruptions is not yet understood.

  14. Adolescent Depression.

    ERIC Educational Resources Information Center

    Evans, Dina M.

    Affective disorder is characterized by maladaptive changes in mood, attitudes, energy level, and physical status. These changes constitute the basic dimensions of depression. Depression results from a combination of genetic and experiential factors. There are sex differences and age differences with regard to depression, and there is a high…

  15. Perinatal depression

    PubMed Central

    Alhusen, Jeanne L.; Alvarez, Carmen

    2016-01-01

    Abstract: Perinatal depression is a common condition with significant adverse maternal, fetal, neonatal, and early childhood outcomes. The perinatal period is an opportune time to screen, diagnose, and treat depression. Improved recognition of perinatal depression, particularly among low-income women, can lead to improved perinatal health outcomes. PMID:26934457

  16. The First Historic Eruption of Nabro, Eritrea: Insights from Thermal and UV Satellite Data

    NASA Astrophysics Data System (ADS)

    Sealing, C. R.; Carn, S. A.; Harris, A. J. L.

    2015-12-01

    In June 2011, the first recorded eruption of Nabro volcano, took place at the border of Eritrea and Ethiopia. This eruption was the largest in what could be considered an ongoing sequence of eruptions in the Afar-Red Sea region since 2005. It halted air travel in northern Africa, contaminated food and water sources, and displaced thousands from their homes. Geographic isolation, previous quiescence, and regional civil unrest meant that this volcano was effectively unmonitored at the time of eruption, and opportunities for field study were limited. The purpose of this study is to explore the quantity of erupted products and the timing and mechanisms of their emplacement using predominantly free, publicly available satellite data. We use MODIS and OMI data to examine rates of lava effusion and SO2 emission, and quantify the amount of erupted products. We also examine published images from other satellites, such as ALI and SEVIRI in order to understand the temporal evolution of the eruption. Synthesizing these data, we then attempt to infer the mechanisms through which the eruption progressed. Examination of satellite data reveals a bimodal eruption, beginning with explosive activity marked by high SO2 emission totalling 1824 - 2299 KT, and extensive ash fall of 270 - 440 km2. This was followed by a period of rapid effusion, producing a ~17 km long lava flow, and a volume of ~22.1 x 106 m3. Mass balance between the SO2 and lava flows reveals no sulfur 'excess', suggesting that nearly all of the degassed magma was extruded. This eruption of Nabro continued for nearly 6 weeks, and may be considered the second largest historic eruption in Africa. This type of work highlights the effectiveness and importance of accessible satellite remote sensing data for the study of active volcanoes, particularly those in remote regions that may be otherwise inaccessible.

  17. Nyiragongo Volcano before the Eruption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Nyiragongo is an active stratovolcano situated on the Eastern African Rift; it is part of Africa's Virunga Volcanic Chain. In a massive eruption that occurred on January 17, 2002, Nyiragongo sent a vast plume of smoke and ash skyward, and three swifly-moving rivers of lava streaming down its western and eastern flanks. Previous lava flows from Nyiragongo have been observed moving at speeds of up to 40 miles per hour (60 kph). The lava flows from the January 17 eruption destroyed more than 14 villages in the surrounding countryside, forcing tens of thousands to flee into the neighboring country of Rwanda. Within one day the lava ran to the city of Goma, situated on the northern shore of Lake Kivu about 12 miles (19 km) south of Nyiragongo. The lava cut a 200 foot (60 meter) wide swath right through Goma, setting off many fires, as it ran into Lake Kivu. Goma, the most heavily populated city in eastern Democratic Republic of Congo, is home to about 400,000 people. Most of these citizens were forced to flee, while many have begun to return to their homes only to find their homes destroyed. This true-color scene was captured by the Enhanced Thematic Mapper Plus (ETM+), flying aboard the Landsat 7 satellite, on December 11, 2001, just over a month before the most recent eruption. Nyiragongo's large crater is clearly visible in the image. As recently as June 1994, there was a large lava lake in the volcano's crater which had since solidified. The larger Nyamuragira Volcano is located roughly 13 miles (21 km) to the north of Nyiragongo. Nyamuragira last erupted in February and March 2001. That eruption was also marked by columns of erupted ash and long fluid lava flows, some of which are apparent in the image as dark greyish swaths radiating away from Nyamuragira. Both peaks are also notorious for releasing large amounts of sulfur dioxide, which presents another health hazard to people and animals living in close proximity. Image by Robert Simmon, based on data supplied

  18. Reconstructing paleoenvironment, eruption mechanism and paleomorphology of the Pliocene Pula maar, (Hungary)

    NASA Astrophysics Data System (ADS)

    Németh, K.; Goth, K.; Martin, U.; Csillag, G.; Suhr, P.

    2008-10-01

    Pula maar is a partially eroded Pliocene maar-diatreme volcano, part of the Mio-Pliocene Bakony-Balaton Highland Volcanic Field. The surficial remnant of the maar-diatreme volcano consists of (1) a distinct depression with a thick post-eruptive lacustrine alginite sediment infill interbedded with coarse-grained volcaniclastic sediments, (2) a narrow marginal zone inside the depression consisting of primary pyroclastic rock units that are interpreted to be partly collapsed and subsided blocks of entire sections from the tephra ring formerly surrounding the maar crater depression, and (3) coarse-grained volcaniclastic debris-flow deposits closely associated with the collapsed primary pyroclastic rock units in the marginal zone. The presence of coherent lava rocks below the crater-fill units, their distribution pattern and their association with scoriaceous beds indicate that, after the maar-diatreme-forming phreatomagmatic explosive activity, small (100 m-scale) scoria and/or spatter cones erupted in the maar crater. These cones are the likely source of the lava flows that partially filled the maar crater basin. The widespread dm-to-m thick basaltic sand and/or silt units at the base of the post-eruptive crater-filling sedimentary succession are interpreted to be reworked volcaniclastic material from the intra-maar scoria/spatter cones as well as from the tephra ring. Based on comparative analyses of 53 core descriptions, this study reveals that the original maar crater basin was larger than previously suggested. The deep level of the maar crater is reconstructed to be a northeast-southwest elongated depression, currently forming a c. 50-m-deep basin. Geomorphological considerations suggest that most of the phreatomagmatic pyroclastic rocks are composed of base surge and tephra fall deposits around the deep maar depression. These allochthonous rock units form a 50-400 m wide zone of proximal tuff-ring sequences. The formation of this zone is inferred to be a result

  19. Monitoring a restless volcano: The 2004 eruption of Mount St. Helens

    USGS Publications Warehouse

    Gardner, C.

    2005-01-01

    Although the precise course of volcanic activity is difficult to predict, volcanologists are pretty adept at interpreting volcanic signals from well-monitored volcanoes in order to make short-term forecasts. Various monitoring tools record effects to give us warning before eruptions, changes in eruptive behavior during eruptions, or signals that an eruption is ending. Foremost among these tools is seismic monitoring. The character, size, depth and rate of earthquakes are all important to the interpretation of what is happening belowground. The first inkling of renewed activity at Mount St. Helens began in the early hours of Sept. 23, when a seismic swarm - tens to hundreds of earthquakes over days to a week - began beneath the volcano. This article details the obervations made during the eruptive sequence.

  20. Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece.

    USGS Publications Warehouse

    Druitt, T.H.

    1985-01-01

    The 18 500 yr BP Cape Riva (CR) eruption of Santorini vented several km3 or more of magma, generating 4 eruption units, each of which is discussed. The eruption sampled a zoned magma chamber containing rhyodacite overlying andesite, and leaks of these magmas were manifested as the Skaros-Therasia lavas preceding the CR eruption. Plinian and initial ignimbrite stages occurred while the magma chamber was overpressured; subsequent underpressuring, due to magma discharge, caused fracturing of the chamber roof, caldera collapse, and eruption of pyroclastic flows from multiple vents. Activation and widening of new conduits during collapse resulted in the rapid escalation of discharge rate favoring the formation of lag breccias by: 1) promoting erosion of lithic debris at the surface vent; and 2) raising surface exit pressures, thereby resulting in a dramatic increase in the grain size of the ejecta.-from Author

  1. Depressive symptoms are associated with higher rates of readmission or mortality after medical hospitalization: A systematic review and meta‐analysis

    PubMed Central

    Pederson, Jenelle L.; Warkentin, Lindsey M.; Majumdar, Sumit R.

    2016-01-01

    Depressive symptoms during a medical hospitalization may be an overlooked prognostic factor for adverse events postdischarge. Our aim was to evaluate whether depressive symptoms predict 30‐day readmission or death after medical hospitalization. We conducted a systematic review of studies that compared postdischarge outcomes by in‐hospital depressive status. We assessed study quality and pooled published and unpublished data using random effects models. Overall, one‐third of 6104 patients discharged from medical wards were depressed (interquartile range, 27%‐40%). Compared to inpatients without depression, those discharged with depressive symptoms were more likely to be readmitted (20.4% vs 13.7%, risk ratio [RR]: 1.73, 95% confidence interval [CI]: 1.16‐2.58) or die (2.8% vs 1.5%, RR: 2.13, 95% CI: 1.31‐3.44) within 30 days. Depressive symptoms were common in medical inpatients and are associated with an increased risk of adverse events postdischarge. Journal of Hospital Medicine 2016;11:373–380. © 2016 The Authors Journal of Hospital Medicine published by Wiley Periodicals, Inc. on behalf of Society of Hospital Medicine PMID:26824220

  2. Depression in hypertensive subjects.

    PubMed

    Ramachandran, V; Parikh, G J; Srinivasan, V

    1983-10-01

    168 patients attending hypertension clinic were randomly selected for the study. They were thoroughly investigated using E.C.G., X-ray chest, Urine analysis, Blood sugar, Blood urea, Serum cholesterol, Serum K, Serum Na, Scrum creatinine and Uric acid level. Detailed psychiatric case history and mental examination was carried out. Beck Rating Scale was used to measure the depression. 25% of hypertensive subjects exhibited depressive features and their mean score in Beck Rating scale is 21.76. The mean score of non-depressives is 4.46. All patients were receiving methyl dopa.25 mg. twice or thrice daily with thiazide diuretic. No significant difference in the incidence of depression with the duration of medication was observed.The hypertension was classified into mild, moderate and severe depending on the diastolic pressure. Depression was more frequent in severe hypertensives but not to the statistically significant level.Further hypertensives were classified into:1. Hypertension without organ involvement2. Hypertension with LVH only3. Hypertension with additional organ involvement4. Malignant hypertensionDepression was significantly more frequent in hypertensives with complications and also hypertensives in whom the B.P. remained uncontrolled. As all the patients were on the same drug, the drug effect is common to all; hence, the higher incidence of depression in hypertensives with complications is due to the limitation and distress caused by the illness. PMID:21847301

  3. The Last Days of the 2010 Eruption at Eyjafjallajökull Volcano

    NASA Astrophysics Data System (ADS)

    Andronico, D.; Scarlato, P.; Cimarelli, C.; Del Bello, E.; Freda, C.; Taddeucci, J.

    2010-12-01

    The 2010 eruption at Eyjafjallajökull ice-capped volcano (Iceland) was the most striking volcanological event occurred in Europe in the last years. Scientific data on the eruptive activity and emitted products have been reported from the Institute of Earth Sciences - Nordic Volcanological Center (http://www2.norvol.hi.is). The onset of the eruption was heralded on 20 March 2010 by the opening of an eruptive fissure at Fimmvorduhals, an area located between the Eyjafjallajökull and Mýrdalsjökull ice caps and bordering the Katla volcano, where the eruptive activity displayed mainly Hawaiian features until 12 April 2010. Two days later, new magma rose up again but shifted just under the summit caldera of the Eyjafjallajökull, where the ice-cap occurred. Since 14 April, the eruption was characterized by explosive phases of different style (from purely magmatic to phreatomagmatic), producing powerful eruption columns that heavily disrupted the international air traffic for several days. After 16 May 2010, the eruptive activity went by an unexpected waning phase characterized by marked decrease of the eruptive phenomena up to their almost total exhaustion on 23 May. We present field data collected during these final days of the eruption. Field surveys and observations were carried out covering an area of about 1200 km2 around the eruptive vents, allowing us to report on the decreasing height of the eruption column and the dispersal of the volcanic plume. PM10 concentrations were measured at ground level using a TSI DUSTTRAKTM aerosol monitor just below the eruption cloud, where we also account for aggregation phenomena of the falling ashes (see also Scarlato et al., this meeting). Values of sedimentation rate of the deposit were measured between 18 and 22 May. In this period we collected more than 15 samples, mainly ashy, from 6 different sites. We have determined grain-size, componentry, density and glass composition of collected samples. Preliminary results show

  4. The Ongoing 2011 Eruption of Cordón Caulle (Southern Andes) and its Related Hazards

    NASA Astrophysics Data System (ADS)

    Amigo, A.; Lara, L. E.; Silva, C.; Orozco, G.; Bertin, D.

    2011-12-01

    On June 4, 2011, at 18:45 UTC, Cordón Caulle volcano (Southern Andes, 40.52S, 72.14W) erupted explosively after 51 years of quiescence. The last eruption occurred in 1960 and was triggered by the great Mw 9.5 Chile earthquake. The ongoing eruption started after 2 months of increased shallow seismicity as recorded by OVDAS (the volcano observatory at Sernageomin). This close monitoring effort allowed a timely eruption forecast with at least 3 hours of warning, which facilitated the crisis response. In addition to this successful performance, for the first time in Chile volcanic hazards were assessed in advance supporting the emergency management. In particular, tephra dispersal was daily forecasted using the ASHFALL advection-diffusion model and potential lahars and PDC impact zones were delineated according to numerical approaches. The first eruptive stage lasted 27 hours. It was characterized by ca. 15-km strong Plinian-like column, associated with the emission of 0.2 - 0.4 km3 of magma (DRE). Tephra fallout mostly occurred in Chile and Argentina, although fine particles and aerosols circumnavigated the globe twice, causing disruptions on air navigation across the Southern Hemisphere. The second ongoing eruptive stage has been characterized by persistent weak plumes and lava emission at effusion rates in the range of 20 and 60 m3/s, which total volume is estimated <0.20 km3 (at the end of July 2011). Eruptive products have virtually the same bulk composition as those of the historical 1921 and 1960 eruptions, corresponding to phenocryst-poor rhyodacites (67 - 70% SiO2) for what a pre-eruptive temperature of ca. 920C could be inferred. In contrast to the previous eruptive cycles, the ongoing eruption has not evolved (at the time of writing) as a fissure eruption although the vent is atop of fault scarp that borders the Pleistocene-Holocene extensional graben of the Cordón Caulle. This episode is a good case of successful eruption forecast and hazards assessment

  5. A survey of early health effects of the Eyjafjallajökull 2010 eruption in Iceland: a population-based study

    PubMed Central

    Carlsen, Hanne Krage; Gislason, Thorarinn; Benediktsdottir, Bryndis; Kolbeinsson, Thorir Bjorn; Hauksdottir, Arna; Thorsteinsson, Throstur

    2012-01-01

    Objective To estimate physical and mental health effects of the Eyjafjallajökull volcanic eruption on nearby residents. Design Cross-sectional study. Setting The Icelandic volcano Eyjafjallajökull erupted on 14 April 2010. The eruption lasted for about 6 weeks and was explosive, ejecting some 8 million tons of fine particles into the atmosphere. Due to prevailing winds, the ash spread mostly to the south and south-east, first over the rural region to the south, later over the Atlantic Ocean and Europe, closing European air space for several days. Participants Residents (n=207) of the most ash-exposed rural area south and east of the volcano. Methods The study period was from 31 May to 11 June 2010. Participants were examined by a physician. To ascertain respiratory health, standardised spirometry was performed before and after the use of a bronchodilator. All adult participants answered questionnaires about mental and physical health, their children's health and the use of protective equipment. Results Every other adult participant reported irritation in eyes and upper airway when exposed to volcanic ash. Adults (n=26) and children (n=5) with pre-existing asthma frequently reported worsening of their symptoms. No serious health problems requiring hospitalisation could be attributed to the eruption. The majority of the participants reported no abnormal physical or mental symptoms to the examining physician. Compared to an age- and gender-matched reference group, the ash-exposed participants reported lower smoking rates and were less likely to have ventilation impairment. Less than 10% of the participants reported symptoms of stress, anxiety or depression. Conclusions Short-term ash exposure was associated with upper airway irritation symptoms and exacerbation of pre-existing asthma but did not contribute to serious health problems. The exposure did not impair respiratory function compared to controls. Outdoor use of protective glasses and face masks was

  6. Changes in methane concentrations after the Pinatubo eruption

    NASA Astrophysics Data System (ADS)

    Banda, Narcisa; Krol, Maarten; van Weele, Michiel; van Noije, Twan; Röckmann, Thomas

    2014-05-01

    Methane is the second most abundant anthropogenic greenhouse gas. Its variability in the atmosphere in the past decades is not fully understood. Particularly large perturbations in methane concentrations were observed after the eruption of Pinatubo in June 1991. The temporal evolution of methane concentrations in the atmosphere is determined by methane emissions and sinks, the main removal from the atmosphere being the reaction with the hydroxyl radical (OH). Natural methane emission from wetlands are influenced by changes in temperature and precipitation. The abundance of OH in the atmosphere, which determines the methane lifetime, is also sensitive to temperature, humidity and the amount of UV radiation. The eruption of Pinatubo in 1991 was the most recent eruption that caused global scale changes in climate and radiation. Sulphate aerosols formed in the stratosphere led to a reduction of the solar radiation reaching the troposphere. Heterogeneous reactions on sulphate aerosols also caused an enhanced depletion of stratospheric ozone. Related changes in the UV radiation reaching the troposphere affected the photolysis reactions involved in the production and recycling of OH. The decrease in tropospheric temperature in the years following the eruption caused a slowdown in the reaction rate between methane and OH, and a reduction in the water vapour needed to form OH. The impact of changes in climate and UV radiation on the concentrations of methane and OH after the eruption of Pinatubo is assessed using the global chemistry and transport model TM5 coupled to the aerosol microphysics module M7. We find the shielding effect of stratospheric sulphate aerosols to be the dominating effect in the first year after the eruption, leading to a decrease of 14 Tg in the methane sink. The decrease in methane burden in the following years is dominantly attributed to stratospheric ozone depletion.

  7. Selective environmental stress from sulphur emitted by continental flood basalt eruptions

    NASA Astrophysics Data System (ADS)

    Schmidt, Anja; Skeffington, Richard A.; Thordarson, Thorvaldur; Self, Stephen; Forster, Piers M.; Rap, Alexandru; Ridgwell, Andy; Fowler, David; Wilson, Marjorie; Mann, Graham W.; Wignall, Paul B.; Carslaw, Kenneth S.

    2016-01-01

    Several biotic crises during the past 300 million years have been linked to episodes of continental flood basalt volcanism, and in particular to the release of massive quantities of magmatic sulphur gas species. Flood basalt provinces were typically formed by numerous individual eruptions, each lasting years to decades. However, the environmental impact of these eruptions may have been limited by the occurrence of quiescent periods that lasted hundreds to thousands of years. Here we use a global aerosol model to quantify the sulphur-induced environmental effects of individual, decade-long flood basalt eruptions representative of the Columbia River Basalt Group, 16.5-14.5 million years ago, and the Deccan Traps, 65 million years ago. For a decade-long eruption of Deccan scale, we calculate a decadal-mean reduction in global surface temperature of 4.5 K, which would recover within 50 years after an eruption ceased unless climate feedbacks were very different in deep-time climates. Acid mists and fogs could have caused immediate damage to vegetation in some regions, but acid-sensitive land and marine ecosystems were well-buffered against volcanic sulphur deposition effects even during century-long eruptions. We conclude that magmatic sulphur from flood basalt eruptions would have caused a biotic crisis only if eruption frequencies and lava discharge rates had been high and sustained for several centuries at a time.

  8. Selective environmental stress from sulphur emitted by continental flood basalt eruptions

    NASA Astrophysics Data System (ADS)

    Schmidt, Anja; Skeffington, Richard; Thordarson, Thorvaldur; Self, Stephen; Forster, Piers; Rap, Alexandru; Ridgwell, Andy; Fowler, David; Wilson, Marjorie; Mann, Graham; Wignall, Paul; Carslaw, Ken

    2016-04-01

    Several biotic crises during the past 300 million years have been linked to episodes of continental flood basalt volcanism, and in particular to the release of massive quantities of magmatic sulphur gas species. Flood basalt provinces were typically formed by numerous individual eruptions, each lasting years to decades. However, the environmental impact of these eruptions may have been limited by the occurrence of quiescent periods that lasted hundreds to thousands of years. Here we use a global aerosol model to quantify the sulphur-induced environmental effects of individual, decade-long flood basalt eruptions representative of the Columbia River Basalt Group, 16.5-14.5 million years ago, and the Deccan Traps, 65 million years ago. For a decade-long eruption of Deccan scale, we calculate a decadal-mean reduction in global surface temperature of 4.5 K, which would recover within 50 years after an eruption ceased unless climate feedbacks were very different in deep-time climates. Acid mists and fogs could have caused immediate damage to vegetation in some regions, but acid-sensitive land and marine ecosystems were well-buffered against volcanic sulphur deposition effects even during century-long eruptions. We conclude that magmatic sulphur from flood basalt eruptions would have caused a biotic crisis only if eruption frequencies and lava discharge rates had been high and sustained for several centuries at a time.

  9. Eruption reconstruction, formation of flow-lobe tumuli and eruption duration in the 5900 BP Helgafell lava field (Heimaey), south Iceland

    NASA Astrophysics Data System (ADS)

    Mattsson, Hannes B.; Höskuldsson, Ármann

    2005-10-01

    The 5900 BP Helgafell eruption started with an intense fire-fountaining phase that deposited scoria and spatter near the vent. Spatter accumulated, agglutinated, and was subsequently emplaced as clastogenic flows. The intense initial phase was followed by effusive emplacement of tube-fed pahoehoe. This type of lava emplacement makes up the bulk of the lava field, and contains abundant inflation features such as tumuli and pressure-ridges. We measured the depths of 358 inflation clefts in tumuli and the thicknesses of the upper-vesicular crust in flow-lobes from the Helgafell lava field. Measurements of altitude between a point-source of lava tubes and the depth of inflation clefts in tumuli suggest that the magmastatic pressure affects initial tumuli formation. The overall growth of tumuli is, however, more dependent on effusion rate and collapse/clogging of individual tubes than on the magmastatic head within tubes. Three areas with abundant tumuli are recognized in the Helgafell lava field, each of which was active for at least 47 days. The average time for tumuli formation is 32 days. Using the crustal measurements of inflation features we test the hypothesis that the total eruption duration can be estimated for a pre-historic volcanic eruption. We chose the Helgafell lava field to test this hypothesis because it has (1) abundant inflation features that are easily measured, and (2) the majority of lava flows emplaced during the eruption are well exposed. Our result shows that the duration of the Helgafell eruption can be estimated to 11-12 months, yielding an average volumetric effusion rate for the Helgafell eruption of 0.05-0.06 km 3/month. This result is very similar to the effusion rates for two known eruptions in the same volcanic system (i.e. the 1963-1967 Surtsey and the 1973 Eldfell eruptions, with effusion rates of 0.02 and 0.04 km 3/month, respectively). Given that all three eruptions occurred within the same volcanic system and that they have similar

  10. Mass eruptions from the Sun

    NASA Astrophysics Data System (ADS)

    Green, Lucie

    2015-08-01

    This review talk will address the recent developments and current understanding of the physical mechanisms that underlie the ejection of matter and magnetic field from the atmosphere of the Sun, known as coronal mass ejections. These eruptions are intitiated within and between active regions throughout an active region's entire lifetime; from the emergence phase, when strong and concentrated magnetic fields are present, through the long decay phase during which time the active region magnetic field fragments and disperses over a larger and larger area, eventually fading into the background quiet sun magnetic field. All coronal mass ejection models invoke the presence of a twisted magnetic field configuration known as a magnetic flux rope either before or after eruption. The observational identification of these structures using remote sensing data of the lower solar atmosphere will be discussed. Do such magnetic field configurations exist in the solar atmosphere prior to the eruption? And if so what can they tell us about the physical mechanisms that trigger and drive coronal mass ejections and the timescales over which an eruptive magnetic field configuration forms? However, not all coronal mass ejections are easily identifiable at the Sun. For example, in situ observations of coronal mass ejections in interplanetary space reveal small magnetic flux rope coronal mass ejections which are not detected leaving the Sun using the remote sensing data. And so-called stealth coronal mass ejections which also have no lower atmosphere signatures. Are there different populations of flux ropes that have different origins? And what might this say about the physical mechanisms behind coronal mass ejections and the consequences for the Sun's evolving global magnetic field?

  11. The 1883 eruption of Krakatau

    NASA Technical Reports Server (NTRS)

    Self, S.; Rampino, M. R.

    1981-01-01

    The 1883 eruption of Krakatau was a modest ignimbrite-forming event. The deposits are primarily coarse-grained dacitic, non-welded ignimbrite. Large explosions produced pyroclastic flows that entered the sea, generating destructive tsunami. Grain-size studies of the ignimbrite suggest that these explosions were not driven by magma-seawater interaction. The total bulk volume of pyroclastic deposits, including co-ignimbrite ash, is estimated to be 18-21 cu km.

  12. The 512 AD eruption of Vesuvius: complex dynamics of a small scale subplinian event

    NASA Astrophysics Data System (ADS)

    Cioni, R.; Bertagnini, A.; Andronico, D.; Cole, P. D.; Mundula, F.

    2011-09-01

    We describe the products of the hitherto poorly known 512 AD eruption at Vesuvius, Italy. The deposit records a complex sequence of eruptive events, and it has been subdivided into eight main units, composed of stratified scoria lapilli or thin subordinate ash-rich layers. All the units formed by deposition from tephra fallout, pyroclastic density currents of limited extent being restricted to the initial stages of the eruption (U2). The main part of the deposit (U3 and U5) is characterized by a striking grain size alternation of fine to coarse lapilli, similar to that often described for mid-intensity, explosive eruptions. The erupted products have a phonotephritic composition, with progressively less evolved composition from the base to the top of the stratigraphic sequence. Based on different dispersal, sedimentological and textural features of the products, we identify five phases related to different eruptive styles: opening phase (U1, U2), subplinian phase (U3 to U5), pulsatory phreatomagmatic phase (U6), violent strombolian phase (U7) and final ash-dominated phase (U8). A DRE volume of 0.025 km3 has been calculated for the total fallout deposit. Most of the magma was erupted during the subplinian phase; lithic dispersal data indicate peak column heights of between 10 and 15 km, which correspond to a mass discharge rate (MDR) of 5 × 106 kg s-1. The lower intensity, violent strombolian phase coincided with the eruption of the least evolved magma; a peak column height of 6-9 km, corresponding to an MDR of 1 ×10 6 kg s -1, is estimated from field data. Phreatomagmatic activity played a minor role in the eruption, only contributing to the ash-rich deposits of U1, U4, U6 and U8. The two most striking features of the 512 AD eruption are the recurrent shifting of the eruption style and the pulsatory nature of the subplinian phase. Basing on a large set of observational data, we propose a model to explain this complex dynamics, also observed in other eruptions of

  13. The magmatic and eruptive response of arc volcanoes to deglaciation: insights from southern Chile

    NASA Astrophysics Data System (ADS)

    Rawson, Harriet; Mather, Tamsin A.; Pyle, David M.; Smith, Victoria C.; Fontijn, Karen; Lachowycz, Stefan; Naranjo, José A.; Watt, Sebastian F. L.

    2016-04-01

    Volcanism exerts a major influence on Earth's atmosphere and surface environments. Understanding feedbacks between climate and long-term changes in rates or styles of volcanism is important, but unresolved. For example, it has been proposed that a pulse of activity at once-glaciated volcanoes contributed to increasing atmospheric carbon dioxide accelerating early Holocene climate change. In plate-tectonic settings where magmatism is driven by decompression melting there is convincing evidence that activity is modulated by changes in ice- or water-loading across glacial/interglacial cycles. The response of subduction-related volcanoes, where the crust is typically thicker and mantle melting is dominated by flux melting, remains unclear. Since arc volcanoes account for 90% of subaerial eruptions, they are the most significant sources of volcanic gases and tephra directly to the atmosphere. Testing the response of arc volcanoes to deglaciation requires careful work to piece together eruption archives. Records of effusive eruptions from long-lived, arc stratovolcanoes are challenging to obtain and date; while deposits from the explosive eruptions, which dominate arc records, are prone to erosion and reworking. Our new high-resolution post-glacial (<18 ka) eruption record from a large stratovolcano in southern Chile (Mocho Choshuenco) provides new insight into the magmatic response following the removal of a regional ice load. We observe significant variations in eruptive flux, eruption size and magma composition across three distinct phases of post-glacial volcanic activity. Phase 1, shortly after deglaciation, was dominated by large explosive eruptions of dacite and rhyolite. During Phase 2 (7.3 - 2.9 ka) eruption rates and eruptive fluxes were lower, and activity was dominated by moderate-scale basaltic-andesite eruptions. For the past 2.4 kyr (Phase 3), eruptive fluxes have been elevated, and dominated by explosive eruptions of intermediate magmas. We propose that

  14. Futurvolc and the Bardarbunga eruption 2014-15 Iceland, success in the field and laboratory.

    NASA Astrophysics Data System (ADS)

    Hoskuldsson, Armann; Jonsdottir, Ingibjorg; Thordarson, Thor

    2016-04-01

    The Bardarbunga volcanic system in Iceland started unrest in August 2014. Seismic activity gradually build up, until magma began to be extruded on surface. The first eruption occurred on the 28th of August and was small and subglacial, the second eruption took place outside the glacier, on the 29th of August and lasted for few hours. Third and largest eruption started on early morning 31st of August. This was to be the largest eruption in Iceland since Laki eruption 1783. The eruption used the same fissure that had opened up on the 28th but was much larger. The fissure was about 2 km long with a curtain of fire along the whole fissure, curtains reaching up to 150 m into the air. The area in which the eruption took place is a glacial river outwash plain, thus relatively flat. Although the eruption site is remote, being in the highlands north of the icecap Vatnajökull, at an average altitude of some 700 m, the flat sandur plain offered a unique opportunity to combine satellite and on site observations methods. The eruption ended on the 27th of February 2015, thus lasting for almost 6 months, during this time some 1.44 km3 of lava was erupted. From day one satellite data from NOAA AVHRR, MODIS, LANDSAT 7 and 8, ASTER, EO-1 ALI, EO-1 HYPERION, SENTINEL-1, RADARSAT-2 COSMO SKYMED and TERRASAR X where collected and used in combination with onsite observation. Resulting data give unique information on the effusion rates in basaltic fissure eruptions and its evolution with time. Further information on flow behavior and cooling of basaltic lava being emplaced in a relatively flat land can be used for future and past predictions. In this talk we shall show how valuable the combination of satellite data to field observation are to be able to precisely monitor on of the largest lava eruption on earth for the past 200 years. The role of Futurevolc and preparedness involved in that work greatly enhanced and facilitated synchronization of onsite and remote data during the

  15. Recovery from Giant Eruptions in Very Massive Stars

    NASA Astrophysics Data System (ADS)

    Kashi, Amit; Davidson, Kris; Humphreys, Roberta M.

    2016-01-01

    We use a hydro-and-radiative-transfer code to explore the behavior of a very massive star (VMS) after a giant eruption—i.e., following a supernova impostor event. Beginning with reasonable models for evolved VMSs with masses of 80 M⊙ and 120 M⊙, we simulate the change of state caused by a giant eruption via two methods that explicitly conserve total energy. (1) Synthetically removing outer layers of mass of a few M⊙ while reducing the energy of the inner layers. (2) Synthetically transferring energy from the core to the outer layers, an operation that automatically causes mass ejection. Our focus is on the aftermath, not the poorly understood eruption itself. Then, using a radiation-hydrodynamic code in 1D with realistic opacities and convection, the interior disequilibrium state is followed for about 200 years. Typically the star develops a ˜400 km s-1 wind with a mass loss rate that begins around 0.1 M⊙ yr-1 and gradually decreases. This outflow is driven by κ-mechanism radial pulsations. The 1D models have regular pulsations but 3D models will probably be more chaotic. In some cases a plateau in the mass-loss rate may persist about 200 years, while other cases are more like η Car which lost >10 M⊙ and then had an abnormal mass loss rate for more than a century after its eruption. In our model, the post-eruption outflow carried more mass than the initial eruption. These simulations constitute a useful preliminary reconnaissance for 3D models which will be far more difficult.

  16. The Atmospheric Impact of the 1991 Mount Pinatubo Eruption

    NASA Technical Reports Server (NTRS)

    Self, Stephen; Zhao, Jing-Xia; Holasek, Rick E.; Torres, Ronnie C.; King, Alan J.

    1993-01-01

    The 1991 eruption of Pinatubo produced about 5 cubic kilometers of dacitic magma and may be the second largest volcanic eruption of the century. Eruption columns reached 40 kilometers in altitude and emplaced a giant umbrella cloud in the middle to lower stratosphere that injected about 17 megatons of SO2, slightly more than twice the largest yielded by the 1982 eruption of El Chichon, Mexico. The SO2 formed sulfate aerosols that produced the largest perturbation to the stratospheric aerosol layer since the eruption of Krakatau in 1883. The aerosol cloud spread rapidly around the Earth in about 3 weeks and attained global coverage by about 1 year after the eruption. Peak local midvisible optical depths of up to 0.4 were measured in late 1992, and globally averaged values were about 0.1 to 0.15 for 2 years. The large aerosol cloud caused dramatic decreases in the amount of net radiation reaching the Earth's surface, producing a climate forcing that was two times stronger than the aerosols of El Chichon. Effects on climate were an observed surface cooling in the northern hemisphere of up to 0.5 to 0.6 C, equivalent to a hemispheric-wide reduction in net radiation of 4 watts per square meter and a cooling of perhaps as large as -0.4 C over large parts of the earth in 1992-93. Climate models seem to have predicted the cooling with a reasonable degree of accuracy. The Pinatubo climate forcing was stronger than the opposite warming of either the El Nino event or anthropogenic greenhouse gases in the period 1991-93. As a result of the presence of the aerosol particles, midlatitude ozone concentrations reached their lowest levels on record during 1992-93, the southern hemisphere 'ozone hole' increased in 1992 to an unprecedented size and ozone depletion rates were observed to be faster than ever before recorded. The atmospheric impact of the Pinatubo eruption has been profound, and it has sparked a lively interest in the role that volcanic aerosols play in climate change

  17. Neighborhood adversity, ethnic diversity, and weak social cohesion and social networks predict high rates of maternal depressive symptoms: a critical realist ecological study in South Western Sydney, Australia.

    PubMed

    Eastwood, John Graeme; Kemp, Lynn Ann; Jalaludin, Bin Badrudin; Phung, Hai Ngoc

    2013-01-01

    The aim of the study reported here is to explore ecological covariate and latent variable associations with perinatal depressive symptoms in South Western Sydney for the purpose of informing subsequent theory generation of perinatal context, depression, and the developmental origins of health and disease. Mothers (n = 15,389) delivering in 2002 and 2003 were assessed at two to three weeks after delivery for risk factors for depressive symptoms. The binary outcome variables were Edinburgh Postnatal Depression Scale (EPDS)> 9 and > 12. Aggregated EPDS > 9 was analyzed for 101 suburbs. Suburb-level variables were drawn from the 2001 Australian Census, New South Wales Crime Statistics, and aggregated individual-level risk factors. Analysis included exploratory factor analysis, univariate and multivariate likelihood, and Bayesian linear regression with conditional autoregressive components. The exploratory factor analysis identified six factors: neighborhood adversity, social cohesion, health behaviors, housing quality, social services, and support networks. Variables associated with neighborhood adversity, social cohesion, social networks, and ethnic diversity were consistently associated with aggregated depressive symptoms. The findings support the theoretical proposition that neighborhood adversity causes maternal psychological distress and depression within the context of social buffers including social networks, social cohesion, and social services. PMID:23821904

  18. Volcanic hazards from Bezymianny- and Bandai-type eruptions

    USGS Publications Warehouse

    Siebert, L.; Glicken, H.; Ui, T.

    1987-01-01

    Major slope failures are a significant degradational process at volcanoes. Slope failures and associated explosive eruptions have resulted in more than 20 000 fatalities in the past 400 years; the historic record provides evidence for at least six of these events in the past century. Several historic debris avalanches exceed 1 km3 in volume. Holocene avalanches an order of magnitude larger have traveled 50-100 km from the source volcano and affected areas of 500-1500 km2. Historic eruptions associated with major slope failures include those with a magmatic component (Bezymianny type) and those solely phreatic (Bandai type). The associated gravitational failures remove major segments of the volcanoes, creating massive horseshoe-shaped depressions commonly of caldera size. The paroxysmal phase of a Bezymianny-type eruption may include powerful lateral explosions and pumiceous pyroclastic flows; it is often followed by construction of lava dome or pyroclastic cone in the new crater. Bandai-type eruptions begin and end with the paroxysmal phase, during which slope failure removes a portion of the edifice. Massive volcanic landslides can also occur without related explosive eruptions, as at the Unzen volcano in 1792. The main potential hazards from these events derive from lateral blasts, the debris avalanche itself, and avalanche-induced tsunamis. Lateral blasts produced by sudden decompression of hydrothermal and/or magmatic systems can devastate areas in excess of 500km2 at velocities exceeding 100 m s-1. The ratio of area covered to distance traveled for the Mount St. Helens and Bezymianny lateral blasts exceeds that of many pyroclastic flows or surges of comparable volume. The potential for large-scale lateral blasts is likely related to the location of magma at the time of slope failure and appears highest when magma has intruded into the upper edifice, as at Mount St. Helens and Bezymianny. Debris avalanches can move faster than 100 ms-1 and travel tens of

  19. Volcanic Eruptions and Climate: Outstanding Research Issues

    NASA Astrophysics Data System (ADS)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  20. REM sleep-like episodes of motoneuronal depression and respiratory rate increase are triggered by pontine carbachol microinjections in in situ perfused rat brainstem preparation.

    PubMed

    Brandes, Ivo F; Stettner, Georg M; Mörschel, Michael; Kubin, Leszek; Dutschmann, Mathias

    2011-05-01

    Hypoglossal nerve activity (HNA) controls the position and movements of the tongue. In persons with compromised upper airway anatomy, sleep-related hypotonia of the tongue and other pharyngeal muscles causes increased upper airway resistance, or total upper airway obstructions, thus disrupting both sleep and breathing. Hypoglossal nerve activity reaches its nadir, and obstructive episodes are longest and most severe, during rapid eye movement stage of sleep (REMS). Microinjections of a cholinergic agonist, carbachol, into the pons have been used in vivo to investigate the mechanisms of respiratory control during REMS. Here, we recorded inspiratory-modulated phrenic nerve activity and HNA and microinjected carbachol (25-50 nl, 10 mm) into the pons in an in situ perfused working heart-brainstem rat preparation (WHBP), an ex vivo model previously validated for studies of the chemical and reflex control of breathing. Carbachol microinjections were made into 40 sites in 33 juvenile rat preparations and, at 24 sites, they triggered depression of HNA with increased respiratory rate and little change of phrenic nerve activity, a pattern akin to that during natural REMS in vivo. The REMS-like episodes started 151 ± 73 s (SD) following microinjections, lasted 20.3 ± 4.5 min, were elicited most effectively from the dorsal part of the rostral nucleus pontis oralis, and were prevented by perfusion of the preparation with atropine. The WHBP offers a novel model with which to investigate cellular and neurochemical mechanisms of REMS-related upper airway hypotonia in situ without anaesthesia and with full control over the cellular environment.

  1. Simulating a multi-phase tephra fall event: inversion modelling for the 1707 Hoei eruption of Mount Fuji, Japan

    NASA Astrophysics Data System (ADS)

    Magill, Christina; Mannen, Kazutaka; Connor, Laura; Bonadonna, Costanza; Connor, Charles

    2015-09-01

    Fuji Volcano last erupted in ad 1707 depositing approximately 40 mm of tephra in the area that is now central Tokyo. New high-resolution data describe 17 eruptive phases occurring over a period of 16 days (Miyaji et al., J Volcanol Geotherm Res 207(3-4):113-129, 2011). Inversion techniques were used in order to best replicate geological data and eyewitness accounts, and to estimate eruption source parameters. Inversion results based on data from individual eruptive phases suggest a total erupted mass of 2.09 × 1012 kg. Comparatively, results based on a single data set describing the entire eruption sequence suggest a total mass of 1.69 × 1012 kg. Values for total erupted mass determined by inversion were compared to those calculated using various curve fitting approaches. An exponential (two-segment) method, taking into account missing distal data, was found to be most compatible with inversion results, giving an erupted mass of 2.52 × 1012 kg when combining individual phases and 1.59 × 1012 kg when utilising a single data set describing the Hoei sequence. Similarly, a Weibull fitting method determined a total erupted mass of 1.54 × 1012 kg for the single data set and compared favourably with inversion results when enough data were available. Partitioning extended eruption scenarios into multiple phases and including detailed geological data close to the eruption source, more accurately replicated the observed deposit by taking into account subtleties such as lobes deposited during transient increases in eruption rate and variations in wind velocity or direction throughout the eruption.

  2. Forces in Erupting Flux Ropes: CMEs and Failed Eruptions

    NASA Astrophysics Data System (ADS)

    Chen, James

    2016-05-01

    A range of dynamical behaviors that can be exhibited by a quasi-statically evolving flux rope is studied. Starting with a CME-like flux rope in equilibrium balanced by the ambient coronal pressure (non-force-free) and an overlying coronal magnetic field (Bc), the poloidal flux is slowly increased, on a timescale much longer than the eruptive timescale of several to tens of minutes. In this configuration, the overlying field Bc provides an external downward restraining force, constituting an effective potential barrier. Slowly increasing poloidal flux causes the flux rope to gradually rise, following a sequence of quasi-static equilibria. As the apex of the flux rope rises past a critical height Z*, slightly higher than the peak of the potential barrier Bc(Z), it expands on a faster, dynamical (Alfvenic) timescale determined by the magnetic field and geometry of the flux rope. The expanding flux rope may reach a new equilibrium at height Z1. Observationally, this behavior would be recognized as a ``failed eruption.'' The new equilibrium flux rope is established if the magnetic tension force due to the toroidal magnetic field component Bt can balance the outward hoop force due to the poloidal component Bp. The flux rope may also expand without reaching a new equilibrium, provided a sufficiennt amount of poloidal flux is injected on a dynamical timescale so that the tension force cannot balance the hoop force. This scenario would result in a CME eruption. The influence of the poloidal flux injection, the Bc(Z) profile, and boundary conditions on the quantitative balance of the forces in an expanding flux rope is elucidated. Potentially observable consequences of the difference scenarios/models are discussed.Work supported by the Naval Research Laboratory Base Research Program

  3. Petrological analysis of the pre-eruptive magmatic process prior to the 2006 explosive eruptions at Tungurahua volcano (Ecuador)

    NASA Astrophysics Data System (ADS)

    Samaniego, Pablo; Le Pennec, Jean-Luc; Robin, Claude; Hidalgo, Silvana

    2011-01-01

    Understanding the processes at the origin of explosive events is crucial for volcanic hazard mitigation, especially during long-lasting eruptions at andesitic volcanoes. This work exposes the case of Tungurahua volcano, whose unrest occurred in 1999. Since this date, the eruptive activity was characterized by low-to moderate explosiveness, including phases with stronger canon-like explosions and regional ash fallout. However, in 2006, a sudden increase of the explosiveness led to pyroclastic flow-forming eruptions on July 14th (VEI 2) and August 16-17th (VEI 3). All magmas emitted from 1999 to 2005, as well as the samples from the 2006 eruptions, have homogeneous bulk-rock andesitic compositions (58-59 wt.% SiO 2), and contain the same mineral assemblage consisting of pl + cpx + opx + mag ± ol. However, during the August 16-17th event, the erupted tephra comprise two types of magmas: a dominant, brown andesitic scoria; and scarce, light-grey pumice representing a subordinate, silica-rich juvenile component. For the andesitic magma, thermobarometric data point to magmatic temperatures ranging from 950 to 1015 °C and pressures in the range of 200 to 250 MPa, which corresponds to 7.5-9.5 km below the summit. Disequilibrium textures in plagioclase and pyroxene phenocrysts, particularly thin overgrowth rims, indicate the recharge of this magma body by mafic magma. Between 1999 and 2005, repeated injections from depth fed the intermittent eruptive activity observed while silica-rich melts were produced by in-situ crystallization in the peripheral parts of the reservoir. In April 2006, the recharge of a primitive magma produced strong convection and homogenisation in the reservoir, as well as pressure increase and higher magma ascent rate after seven years of only moderately explosive activity. This work emphasizes the importance of petrological studies in constraining the pre-eruptive magmatic conditions and processes, as a tool for understanding the fundamental causes

  4. Using Lava Inflation Structures to Estimate Eruption Duration in Fossil Lava Fields: the Helgafell Eruption 5900 BP

    NASA Astrophysics Data System (ADS)

    Mattsson, H.; Höskuldsson, A.

    2002-12-01

    Lava inflation structures, such as tumuli and pressure ridges, are common features in subarial pahoehoe flow fields but has also been reported from submarine lava flows. Tumuli form by clogging of individual lava tubes inside a flow field or when the lava supply rate exceeds the flow front displacement, which causes inflation of previously formed crust and formation of the characteristic whale-back shape of tumuli. Axial and radial clefts cut the tumuli ("inflation-clefts"). Measurements on active lava flows has shown that the time (during which inflation occur) correlates posetively with the square of the measured inflation-cleft depth, and can therefore be used to calculating active time of inflation by measuring cleft depths in fossil flows. Over threehundred measurements of inflation cleft depths were collected from tumuli and pressure ridges located in the Helgafell lava field, Vestmannaeyjar, South Iceland. The Helgafell eruption occurred approximately 5900 BP, and emplaced the largest lava flow on the island covering 6.5 km2 (~ 0.6 km3 DRE). The erupted lava are plagioclase-phyric alkali basalt, exhibiting considerable variation (7.0 wt% MgO to 4.4 wt% MgO) due to flow fractionation and incorporation of large (< 7 cm) plagioclase xenocrysts. Measurements of inflation cleft depths show that a minimum crustal thickness of 0.3 m is required to initiate tumulus growth. The deepest clefts are located furthest away from the vent, which coinsides with the largest elevation difference between tumuli and source (e.g. uppermost point of lava tube). The cleft measurements where combined with careful stratigraphic mapping in order to estimate the total duration of the Helgafell eruption. It is important to keep in mind that tumuli are surface features and only reflect inflation of the uppermost flows. The maximum time calculated for active inflation must therefore correspond to a minimum eruption duration. By doing these calculations, and adding measurements of tumuli

  5. Ghost Remains After Black Hole Eruption

    NASA Astrophysics Data System (ADS)

    2009-05-01

    NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

  6. Ghost Remains After Black Hole Eruption

    NASA Astrophysics Data System (ADS)

    2009-05-01

    NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

  7. Volatile fluxes during flood basalt eruptions and potential effects on the global environment: A Deccan perspective

    NASA Astrophysics Data System (ADS)

    Self, Stephen; Widdowson, Mike; Thordarson, Thorvaldur; Jay, Anne. E.

    2006-08-01

    We examine the role that flood basalt eruptions may have played during times of mass extinction through the release of volcanic gases. Continental flood basalt provinces have formed by numerous eruptions over a short period of geologic time, characteristically a few million years. Within this period, a short-lived climactic phase that lasts about 1 Ma typically emplaces a large proportion of the lava volume. This phase consists of a series of huge eruptions, each yielding 10 3-10 4 km 3 of magma. Each eruption lasted on the order of a decade or more, and built an immense pāhoehoe-dominated lava flow field by eruptive activity along fissures tens to hundreds of km long. High fire-fountains, emanating from vents along the fissures, at times sustained eruption columns that lofted gas and ash into the upper troposphere and lower stratosphere while the lava flows covered huge areas. The combination of large eruption magnitudes, maintained high effusion rates during eruptions, and the repeated nature of the characteristic, large-scale eruptive activity occurs in Earth history only during periods of flood basalt volcanism. Based on recent analogs and determination of volatile contents of ancient flood basalt lavas, we estimate that individual eruptions were capable of releasing 10,000 Tg of SO 2, resulting in atmospheric loadings of 1000 Tg a - 1 during a sustained decade-long eruptive event. We apply this model of flood basalt volcanism to estimate the potential mass of CO 2 and SO 2 released during formation of the ˜ 65 Ma Deccan province. The Deccan lava-pile contains the record of hundreds of enormous pāhoehoe flow-fields erupted within a period of about 1 Ma. Consequently, atmospheric perturbations associated with SO 2 emissions from just one of these long-lasting eruptions were likely to have been severe, and constantly augmented over a decade or longer. By contrast, the amounts of CO 2 released would have been small compared with the mass already present in the

  8. The magmatic and eruptive response of arc volcanoes to deglaciation: insights from southern Chile

    NASA Astrophysics Data System (ADS)

    Mather, T. A.; Rawson, H. L.; Smith, V.; Fontijn, K.; Lachowycz, S.; Pyle, D. M.; Naranjo, J. A.; Watt, S. F.

    2015-12-01

    In plate-tectonic settings where magmatism is driven by decompression melting there is convincing evidence that activity is modulated by changes in ice- or water-loading across glacial/interglacial cycles. In contrast, the response of subduction-related volcanoes, where the crust is typically thicker and mantle melting is dominated by flux melting, remains unclear. The large areas spanned by arcs, and the typical activity at subduction zone volcanoes present particular challenges when compiling regional eruption archives. Records of effusive eruptions from long-lived, arc stratovolcanoes are challenging to obtain, and date; while deposits from the explosive eruptions, which dominate arc records, are prone to erosion and reworking. Here we use a rare high-resolution post-glacial (<18 ka) eruption record from a large stratovolcano (Mocho-Choshuenco) in southern Chile to gain new insight into the magmatic response to removal of an ice load; variation in eruptive flux, eruption size and magma composition are observed and divided into three distinct phases based on style of activity and erupted composition. Phase 1, shortly after deglaciation, was dominated by large explosive eruptions of dacite and rhyolite. During Phase 2 (7.3 - 2.9 ka) eruption rates and eruptive fluxes were lower, and activity was dominated by moderate-scale basaltic-andesite eruptions. Since 2.4 ka (Phase 3) eruptive fluxes have been elevated, and dominated by explosive eruptions of more intermediate magmas. This time-varying behaviour reflects changes in crustal plumbing systems, and magma storage timescales. During glaciations, magmas stall and differentiate to form large, evolved crustal reservoirs. After the load is removed, much of this stored magma is erupted (Phase 1). Subsequently, less-differentiated melts infiltrate the shallow crust (Phase 2). Then, as storage timescales increase, volcanism returns to more evolved compositions (Phase 3). On short (<10 kyr) timescales these variations are

  9. Depression in Older Adults

    PubMed Central

    Fiske, Amy; Wetherell, Julie Loebach; Gatz, Margaret

    2010-01-01

    Depression is less prevalent among older adults than among younger adults but can have serious consequences. Over half of cases represent a first onset in later life. Although suicide rates in the elderly are declining, they are still higher than in younger adults and more closely associated with depression. Depressed older adults are less likely to endorse affective symptoms and more likely to display cognitive changes, somatic symptoms, and loss of interest than are younger adults. Risk factors leading to the development of late life depression likely comprise complex interactions among genetic vulnerabilities, cognitive diathesis, age-associated neurobiological changes, and stressful events. Insomnia is an often overlooked risk factor for late life depression. We suggest that a common pathway to depression in older adults, regardless of which predisposing risks are most prominent, may be curtailment of daily activities. Accompanying self-critical thinking may exacerbate and maintain a depressed state. Offsetting the increasing prevalence of certain risk factors in late life are age-related increases in psychological resilience. Other protective factors include higher education and socioeconomic status, engagement in valued activities, and religious or spiritual involvement. Treatments including behavioral therapy, cognitive behavioral therapy, cognitive bibliotherapy, problem-solving therapy, brief psychodynamic therapy, and life review/reminiscence therapy are effective but too infrequently used with older adults. Preventive interventions including education for individuals with chronic illness, behavioral activation, cognitive restructuring, problem-solving skills training, group support, and life review have also received support. PMID:19327033

  10. Epilepsy coexisting with depression.

    PubMed

    Błaszczyk, Barbara; Czuczwar, Stanisław J

    2016-10-01

    Depression episodes in epilepsy is the most common commorbidity, affecting between 11% and 62% of patients with epilepsy. Although researchers have documented a strong association between epilepsy and psychiatric comorbidities, the nature of this relationship is poorly understood. The manifestation of depression in epilepsy is a complex issue having many interacting neurobiological and psychosocial determinants, including clinical features of epilepsy (seizure frequency, type, foci, or lateralization of foci) and neurochemical or iatrogenic mechanisms. Other risk factors are a family history of psychiatric illness, particularly depression, a lack of control over the seizures and iatrogenic causes (pharmacologic and surgical). In addition, treatment with antiepileptic drugs (AEDs) as well as social coping and adaptation skills have also been recognised as risk factors of depression associated with epilepsy. Epilepsy may foster the development of depression through being exposed to chronic stress. The uncertainty and unpredictability of seizures may instigate sadness, loneliness, despair, low self-esteem, and self-reproach in patients with epilepsy and lead to social isolation, stigmatization, or disability. Often, depression is viewed as a reaction to epilepsy's stigma and the associated poor quality of life. Moreover, patients with epilepsy display a 4-5 higher rate of depression and suicide compared with healthy population. PMID:27634589

  11. New insights into eruptive activity and lava flow hazard at Nyamulagira volcano, D.R.C., from a new GIS-based lava flow map

    NASA Astrophysics Data System (ADS)

    Smets, B.; Kervyn, M.; Kervyn, F.; D'Oreye, N.; Wauthier, C.

    2010-12-01

    Nyamulagira, located in the western branch of the East African Rift (EAR), is Africa’s most active volcano with one eruption every 2 - 4 years. A map of Nyamulagira lava flows was produced during the 1960’s by Thonnard et al. (1965). This map, which results from the mosaicking of several aerial photographs, contains locally some geographic inaccuracies. The photo-interpretation also led in places to the discrimination of lava units not corresponding to any flow boundaries in the field. Finally, 19 eruptions occurred since this first edition, which causes it to be outdated and of limited use to document the recent eruptive history. Recently, Smets et al. (2010) have produced a new map of lava flows using a combination of optical and radar satellite imagery. This map is GIS-based and can be quickly updated during/after each eruption. Using the new lava flow map of Nyamulagira and a compilation of bibliographic/field information of the last 31 eruptions, the evolution of eruptive activity since the early 1900’s was reconstructed and the volume of erupted lava estimated for each eruption from 1938 to 2010. The spatio-temporal evolution of eruptive activity suggests a strong control from the rift tectonics but also from inherited basement structures on the location, the fissure orientation and the relative lava volume for the successive eruptions. The time lapse after each eruption is strongly correlated with the erupted volume of lava. The 1938-40 eruption is a key event in the volcano recent history, as the corresponding caldera collapse led to an increase of flank eruptions. Nyamulagira flank eruptions systematically destroy large areas of the protected forest of the Virunga National Park, a UNESCO World Heritage in danger since 1994. The lava flows from distal eruptions or from exceptionally high effusion rate or volume events also threaten local population, mainly south of the main edifice near Lake Kivu.

  12. Concurrent Validity of the Millon Clinical Multiaxial Inventory Depression Scales.

    ERIC Educational Resources Information Center

    Goldberg, Joel O.; And Others

    1987-01-01

    Compared two new measures of depression (Millon Multiaxial Inventory Dysthymia and Major Depression subscales) with two established instruments: Beck Depression Inventory, a self-report measure which emphasizes the cognitive-affective aspects of depression, and Hamilton Rating Scale for Depression, an interview measure that emphasizes somatic…

  13. The Relationship of Perfectionism, Depression, and Therapeutic Alliance during Treatment for Depression: Latent Difference Score Analysis

    ERIC Educational Resources Information Center

    Hawley, Lance L.; Ho, Moon-Ho Ringo; Zuroff, David C.; Blatt, Sidney J.

    2006-01-01

    The authors examined the longitudinal relationship of patient-rated perfectionism, clinician-rated depression, and observer-rated therapeutic alliance using the latent difference score (LDS) analytic framework. Outpatients involved in the Treatment for Depression Collaborative Research Program completed measures of perfectionism and depression at…

  14. Seismic array observations for monitoring phreatic eruptions in Iwojima Island, Japan

    NASA Astrophysics Data System (ADS)

    Ueda, H.; Kawaguchi, R.; Chiba, K.; Fujita, E.; Tanada, T.

    2015-12-01

    Iwojima is an active volcanic island located within a 10 km wide submarine caldera about 1250 km to the south of Tokyo, Japan. The volcanic activity is characterized by intensive earthquake activity associated with an island-wide uplift with high uplift rate (30~40 cm/year) and hydrothermal activity. In the last 10 years, phreatic eruptions took place in and near the island in 2012, 2013, and 2015. In such restless volcano, predictions and detections of occurrence points of phreatic eruptions are important for ensuring safety of residents. In the previous studies, we found that the earthquake activity of Iwojima highly correlates with the island wide large uplift, but the precursory activity of the phreatic eruption in 2012 was deviated from the correlation (Ueda et al. 2013 AGU Fall Meeting). For prediction of occurrence points of phreatic eruptions and investigation of the eruption mechanism, we began observation by seismic arrays at two areas in December 2014. The seismic arrays enable to locate epicenters of volcanic tremors, which are not well located by existing seismic stations. In May and June 2015, Japan Maritime Self-Defense Force stayed in Iwojima and a live camera of Japan Meteorological Agency found very small phreatic eruptions occurred at the northern beach. Existing seismic stations could not detect seismic signals related with the eruptions. The seismic array could detect weak seismic signals related with the eruptions. Although the seismic arrays could not detect precursory signals because of too small eruption, we expect the seismic arrays can detect precursory seismic signals suggesting occurrence points of small or medium-sized phreatic eruptions. The seismic arrays also detected epicenters of harmonic and monotonic tremors took place at an active fumarolic field in the north earthen part of Iwojima. The apparent velocity of seismic waves (~1km/s) strongly suggests that the tremors relate with hydrothermal activity near ground surface.

  15. Transitions between explosive and effusive phases during the cataclysmic 2010 eruption of Merapi volcano, Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Preece, Katie; Gertisser, Ralf; Barclay, Jenni; Charbonnier, Sylvain J.; Komorowski, Jean-Christophe; Herd, Richard A.

    2016-08-01

    Transitions between explosive and effusive activity are commonly observed during dome-forming eruptions and may be linked to factors such as magma influx, ascent rate and degassing. However, the interplay between these factors is complex and the resulting eruptive behaviour often unpredictable. This paper focuses on the driving forces behind the explosive and effusive activity during the well-documented 2010 eruption of Merapi, the volcano's largest eruption since 1872. Time-controlled samples were collected from the 2010 deposits, linked to eruption stage and style of activity. These include scoria and pumice from the initial explosions, dense and scoriaceous dome samples formed via effusive activity, as well as scoria and pumice samples deposited during subplinian column collapse. Quantitative textural analysis of groundmass feldspar microlites, including measurements of areal number density, mean microlite size, crystal aspect ratio, groundmass crystallinity and crystal size distribution analysis, reveal that shallow pre- and syn-eruptive magmatic processes acted to govern the changing behaviour during the eruption. High-An (up to ˜80 mol% An) microlites from early erupted samples reveal that the eruption was likely preceded by an influx of hotter or more mafic magma. Transitions between explosive and effusive activity in 2010 were driven primarily by the dynamics of magma ascent in the conduit, with degassing and crystallisation acting via feedback mechanisms, resulting in cycles of effusive and explosive activity. Explosivity during the 2010 eruption was enhanced by the presence of a `plug' of cooled magma within the shallow magma plumbing system, which acted to hinder degassing, leading to overpressure prior to initial explosive activity.

  16. Bimodal Distribution of Geyser Preplay Eruptions: Lone Star Geyser, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Namiki, A.; Hurwitz, S.; Murphy, F.; Manga, M.

    2014-12-01

    Geyser eruption intervals are determined by rates of water and heat discharge into shallow subsurface reservoirs and the conduit. In some geysers, small amounts of water discharge prior to a main eruption ('Preplay') can affect eruption intervals. Water discharge during preplay reduces the hydrostatic pressure, which in turn, induces boiling of water that is at, or near the critical temperature. Ascending steam slugs from depth can also lead to shorter eruption intervals (Namiki et al., 2014). In April 2014, we carried a five day experiment at Lone Star Geyser, Yellowstone National Park. Eruptions and their preplays were recorded with an infrared sensor that measured temperature variations immediately above the geyser cone (3.4~m high), temperature loggers that measured water temperature at the base of the cone and in the outflow channels, and visual observations. At Lone Star Geyser, during the preplay phase of the eruption, mainly liquid water is erupted, whereas the main phase of the eruption begins with the liquid-water dominated eruption and turns into the steam discharge. The temperature rise in an outflow channel indicates the occurrence of preplays and initiation of the main eruption. The acquired data suggests that the preplay patterns of Lone Star Geyser are vigorous and complex, consistent with previous observations (Karlstrom et al., 2013). Our new observations reveal two typical styles: 1) vigorous preplays with few events (<5) and long intervals (>20~minutes) that last approximately 40~minutes, and 2) less vigorous preplays that include several events (>5) with short intervals (few minutes), and continue approximately for one hour. Probability distributions of preplay durations show two peaks indicating the bimodal activity. The bimodality of Lone Star preplays may be a result of subtle change of temperature distribution in a convecting reservoir which has been observed in laboratory experiments (Toramaru and Maeda, 2013).

  17. Characterizing the first historic eruption of Nabro, Eritrea: Insights from thermal and UV remote sensing

    NASA Astrophysics Data System (ADS)

    Sealing, Christine R.

    June 2011 saw the first historic eruption of Nabro volcano, one of an ongoing sequence of eruptions in the Afar-Red Sea region since 2005. It halted air travel in northern Africa, contaminated food and water sources, and displaced thousands from their homes. Due to its remote location, little was known about this event in terms of the quantity of erupted products and the timing and mechanisms of their emplacement. Geographic isolation, previous quiescence and regional civil unrest meant that this volcano was effectively unmonitored at the time of eruption, and opportunities for field study are limited. Using free, publicly available satellite data, I examined rates of lava effusion and SO2 emission in order to quantify the amount of erupted products and understand the temporal evolution of the eruption, as well as explore what information can be gleaned about eruption mechanisms using remote sensing data. These data revealed a bimodal eruption, beginning with explosive activity marked by high SO2 emission totalling 1824 - 2299 KT, and extensive ash fall of 270 - 440 km2. This gave way to a period of rapid effusion, producing a ˜17 km long lava flow, and a volume of ˜22.1 x 106 m3. Mass balance between the SO2 and lava flows reveals no sulfur 'excess', suggesting that nearly all of the degassed magma was extruded. The 2011 eruption of Nabro lasted nearly 6 weeks, and may be considered the second largest historic eruption in Africa. Work such as this highlights the importance of satellite remote sensing for studying and monitoring volcanoes, particularly those in remote regions that may be otherwise inaccessible.

  18. The magnitude and impact of the Youngest Toba Tuff super-eruption

    NASA Astrophysics Data System (ADS)

    Costa, Antonio; Smith, Victoria; Macedonio, Giovanni; Matthews, Naomi

    2014-08-01

    Super-eruptions, orders of magnitude larger than eruptions experienced in historic times, have devastated wide areas by pyroclastic flows, covered continent-size areas by ash fallout, and injected large quantities of aerosols into the stratosphere affecting global climate. The Youngest Toba Tuff (YTT) is the largest known super-eruption in the Quaternary. Here we reconstructed the ultra-distal volcanic ash dispersal during this super-eruption using a computational ash dispersal model, which provides insights into the eruption dynamics and the impact of the event. The method uses a 3D time-dependent tephra dispersion model, a set of wind fields, and several tens of thickness measurements of the YTT tephra deposit. Results reveal that the YTT eruption dispersed ~8600 km3 (~3800 km3 dense rock equivalent, DRE) of ash, covering ~40 million km2 with more than 5 mm of ash. These new fallout volume estimations indicate that the total volume of the material erupted (including the massive pyroclastic density current, 1500 km3 DRE, deposits on Sumatra) was ~5300 km3 DRE. Simulation results indicate that the eruption had a very large mass flow rate and that the umbrella cloud, associated with the eruption plume, spread as an enormous gravity current around the neutral buoyancy level. The YTT tephra forms a key chronostratigraphic marker in the sedimentary sequences, and is particularly useful for constraining the age of the palaeoenvironmental and archaeological records, and synchronizing these archives to investigate temporal relationships. These new constraints on the extent of the YTT deposit are therefore particularly useful for cryptotephra studies that aim to find non-visible tephra layers for these chronological purposes. This method used to constrain volcanological parameters of eruptions in the past provides insights into the dispersal processes, and allows the amount of volatiles released to be estimated which is crucial to assessing the impact of such events.

  19. How and Why Do Geysers Erupt?

    NASA Astrophysics Data System (ADS)

    Manga, M.

    2014-12-01

    Geysers are features that produce episodic eruptions of water, steam and sometimes non-condensable gases. Natural geysers are rare, with fewer than 1,000 worldwide. They are more than curiosities and popular tourist attractions: they offer a direct window into geothermal processes, and may serve as a natural small-scale laboratory to study larger-scale eruptive process such as those at volcanoes, and other self-organized, intermittent processes that result from phase separation and localized input of energy and mass. Despite > 200 years of scientific study, basic questions remain: Do eruptions begin from the bottom or top of the geyser? What controls eruption duration? Why do eruptions end? What are the required special subsurface geometries? Why are some geysers periodic, and others irregular? How and why do they respond to external influences such as weather, tides, and earthquakes? This presentation will review new insights from field studies at Lone Star geyser, Yellowstone National Park, geysers in the El Tatio geyser field, Chile, and laboratory models. At Lone Star we infer that dynamics are controlled by thermal and mechanical coupling between the conduit and a deeper, laterally-offset reservoir (called a "bubble trap" in previous studies). At El Tatio, we measured pressure and temperature within geysers over multiple eruption cycles: this data document the heating of liquid water by steam delivered from below. The laboratory experiments reveal how episodic release of steam from a bubble trap prepares a conduit for eruption and can generate a range of eruption intensities. In all cases, the eruption initiation, duration and termination are controlled by the interaction between the accumulation and transport of steam and liquid, and modulated by the geometry of the geyser's plumbing. Time series of thousands of eruptions confirm that internal processes control eruptions, with only pool geysers showing a sensitivity to air temperature; only very large stress

  20. The antibody response in seabather's eruption.

    PubMed

    Burnett, J W; Kumar, S; Malecki, J M; Szmant, A M

    1995-01-01

    Thirty-six of 44 patients with seabather's eruption had specific IgG antibodies against Linuche unguilata (thimble jelly) medusae antigen. ELISA detected antibodies in serum stored for 10 years. The extent of the cutaneous eruption or sting severity was correlated with antibody titer. Antibodies were detected in patients acquiring the eruption in Florida, the Bahamas and Aruba, reflecting the habitat of these jellyfish. This serological assay can be useful to confirm the clinical diagnosis. PMID:7778134

  1. Source evolution and longevity of the Lusi mud eruption, Indonesia

    NASA Astrophysics Data System (ADS)

    Rudolph, M. L.; Shirzaei, M.; Manga, M.; Fukushima, Y.

    2012-12-01

    The ongoing eruption of the Lusi mud volcano (East Java, Indonesia), which began on May 29, 2006, has displaced more than 60,000 people and cost billions of US dollars in economic losses. We measured ground deformation near Lusi using interferometric processing of 46 L-band synthetic aperture radar images acquired by the ALOS satellite between 2006 and 2011. We analyzed the ground deformation using principal component analysis (PCA) and found that the dominant spatial mode of ground deformation is decreasing exponentially in amplitude with a timescale of 2.1+0.5-0.3 years, implying that the eruption rate will decrease by an order of magnitude, to less than 1000 m3/day, by 2016±1 year, much sooner than previously anticipated (Istadi et al. 2009, Davies et al. 2011, Rudolph et al. 2011). We also modeled the observed ground deformation to determine the mud chamber radius and pressure time history subject to geologic constraints on depth and thickness. The co-evolution of the mud chamber geometry and pressure suggest progressive mobilization of mud during the eruption, a process analogous to one that may occur in large explosive silicic volcanic eruptions.

  2. Eruptive Current Sheets Trailing SOHO/LASCO CMEs

    NASA Astrophysics Data System (ADS)

    Webb, David F.

    2015-04-01

    Current sheets are important signatures of magnetic reconnection during the eruption of solar magnetic structures. Many models of eruptive flare/Coronal Mass Ejections (CMEs) involve formation of a current sheet connecting the ejecting CME flux rope with the post-eruption magnetic loop arcade. Current sheets have been interpreted in white light images as narrow rays trailing the outward-moving CME, in ultraviolet spectra as narrow, bright hot features, and with different manifestations in other wavebands. This study continues that of Webb et al. (2003), who analyzed SMM white light CMEs having candidate magnetic disconnection features at the base of the CME. About half of those were followed by coaxial, bright rays suggestive of newly formed current sheets, and Webb et al. (2003) presented detailed results of analysis of those structures. In this work we extend the study of white light eruptive current sheets to the more sensitive and extensive SOHO/LASCO coronagraph data on CMEs. We comprehensively examined all LASCO CMEs during two periods that we identify with the minimum and maximum activity of solar cycle 23. We identified ~130 ray/current sheets during these periods, nearly all of which trailed CMEs with concave-outward backs. The occurrence rate of the ray/current sheets is 6-7% of all CMEs, irrespective of the solar cycle. We analyze the rays for durations, speeds, alignments, and motions and compare the observational results with some model predictions.

  3. Current Sheet Properties and Dynamics During Sympathetic Breakout Eruptions

    NASA Astrophysics Data System (ADS)

    Lynch, B. J.; Edmondson, J. K.

    2013-12-01

    We present the continued analysis of the high-resolution 2.5D MHD simulations of sympathetic magnetic breakout eruptions from a pseudostreamer source region. We examine the generation of X- and O-type null points during the current sheet tearing and track the magnetic island formation and evolution during periods of reconnection. The magnetic breakout eruption scenario forms an overlying 'breakout' current sheet that evolves slowly and removes restraining flux from above the sheared field core that will eventually become the center of the erupting flux rope-like structure. The runaway expansion from the expansion-breakout reconnection positive feedback enables the formation of the second, vertical/radial current sheet underneath the rising sheared field core as in the standard CHSKP eruptive flare scenario. We will examine the flux transfer rates through the breakout and flare current sheets and compare the properties of the field and plasma inflows into the current sheets and the reconnection jet outflows into the flare loops and flux rope ejecta.

  4. Impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, M.; Brinkop, S.; Jöckel, P.

    2015-12-01

    Volcanic eruptions can have significant impact on the earth's weather and climate system. Besides the subsequent tropospheric changes also the stratosphere is influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour after the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as important sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on the tropospheric water vapour and ENSO are evident.

  5. Impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, Michael; Brinkop, Sabine; Jöckel, Patrick

    2016-05-01

    Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg - Modular Earth Submodel System (ECHAM/MESSy) Atmospheric Chemistry (EMAC) model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño-Southern Oscillation (ENSO) are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

  6. Eruptive shearing of tube pumice: pure and simple

    NASA Astrophysics Data System (ADS)

    Dingwell, Donald B.; Lavallée, Yan; Hess, Kai-Uwe; Flaws, Asher; Marti, Joan; Nichols, Alexander R. L.; Gilg, H. Albert; Schillinger, Burkhard

    2016-09-01

    Understanding the physicochemical conditions extant and mechanisms operative during explosive volcanism is essential for reliable forecasting and mitigation of volcanic events. Rhyolitic pumices reflect highly vesiculated magma whose bubbles can serve as a strain indicator for inferring the state of stress operative immediately prior to eruptive fragmentation. Obtaining the full kinematic picture reflected in bubble population geometry has been extremely difficult, involving dissection of a small number of delicate samples. The advent of reliable high-resolution tomography has changed this situation radically. Here we demonstrate via the use of tomography how a statistically powerful picture of the shapes and connectivity of thousands of individual bubbles within a single sample of tube pumice emerges. The strain record of tube pumice is modelled using empirical models of bubble geometry and liquid rheology, reliant on a constraint of magmatic water concentration. FTIR analysis reveals an imbalance in water speciation, suggesting post-eruption hydration, further supported by hydrogen and oxygen isotope measurements. Our work demonstrates that the strain recorded in the tube pumice dominated by simple shear (not pure shear) in the late deformational history of vesicular magma before eruption. This constraint in turn implies that magma ascent is conditioned by a velocity gradient (across the conduit) at the point of origin of tube pumice. Magma ascent accompanied by simple shear should enhance high eruption rates inferred independently for these highly viscous systems.

  7. [Atypical depression].

    PubMed

    Escande, M; Boucard, J

    1999-04-01

    The principal atypical aspects of depressive disease are: minor and attenued aspects, monosymptomatic and atypical aspects (food disorders and sleep disorders), masqued aspects (somatoform, anxious, characterial and addict disorders), atypical aspects of child (anxious nevrotical disorder), pseudo-demented and characterial aspects of aged subjects. Facing to these aspects, the diagnosis of depression is evoqued on: the recent and fast advent of these disorders, their morning predominance, their recurrent character, the state of attenued depressive symptoms (anhedonia), the positive responsiveness to treatment.

  8. Magma discharge and lava flow field growth in the Nornahraun/Bardarbunga eruption Iceland.

    NASA Astrophysics Data System (ADS)

    Hoskuldsson, Armann; Jónsdóttir, Ingibjörg; Riishus, Morten S.; Pedersen, Gro B. M.; Gudmundsson, Magnus T.; Thordarson, Torvaldur; Drouin, Vincent; Futurevolc IES field work Team

    2015-04-01

    Bardarbunga volcano was reactivated by an intense seismic swarm on 16/8 2014. The seismic swarm originating at the central volcano propagated north out into the associated fissure swarm during following days. As it reached the outwash plains of Jokulsa a fjollum a subaerial eruption began. Three eruptions have taken place on the outwash plane in the event, on the 29/8, 31/8 to present and on 5/9. In this presentation we discuss the second eruption that began on the 31/8 and how we do approach magma discharge parameters by combination of field observation and satellite photogrammetry. The eruption took place at the northern end of the eruptive fissure from AD 1797 and the lava was expelled out onto to relatively flat outwash plains of the glacial river Jokulsa a Fjollum thus access to eruptive products was relatively easy. It was clear from the first moments of the eruption that it had a high initial effusion rate, with lava covering the sandur plains at the rate of 25-30 m2/s. Within the first week the lava flow had covered more than 18 km2. That amounts to an average effusion rate between 195 to 280 m3/s. On the 11/9 the lava flow had grown to 25 km2, at that time effusion rate was between 140 to 247 m3/s, The lava stopped advancing and started to grow sideways and inflating. This reoccurred on the 26/9 and 12/10, with clockwise horizontal stacking of lobes to the south. From mid-November the lava growth has been controlled by tube-fed lava streams, at first generating breakouts close to the vent area and then during the last week before Christmas breaking out at the far NE end of the lava flow. As the eruption proceeded effusion rate gradually decreased and at the time of writing it is down to 9 to 76 m3/s. For assessment of areal extent of the lava field a combination of ground gps tracking and satellite photogrammetry was used. However one of the main challenges in the monitoring of the eruption was to obtain volumetric effusion rates. In the beginning of the

  9. Coping with Unexpected Events: Depression and Trauma

    MedlinePlus

    ... or worsen, such as lack of interest in school or friends, increased or decreased eating or sleeping, ... PTSD and Depression Rates of depression are very high in people who experience PTSD. In one study ...

  10. Tornados and Transverse Oscillations during Prominence Eruption

    NASA Astrophysics Data System (ADS)

    Banerjee, Dipankar; Chandrashekhar, K.; Morton, Richard; Pant, Vaibhav; Datta, Ajanta

    2016-07-01

    We report and analyse different phases of a prominence eruption. The winding-unwinding of two footpoints and a tornado like swirling motion is studied. The prominence eruption is observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). This prominence eruption is associated with a CME at a central principal angle of 340 degree, according to the SOHO/LASCO CME catalogue. We can observe the prominence threads and the time distance maps reveal that the loop threads are entangled. We also study the transverse oscillations in the threads. Swirling motions after the eruptions are also quantified and its possible link with the CME kinematics is also studied

  11. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  12. Why do Martian Magmas erupt?

    NASA Astrophysics Data System (ADS)

    Balta, J. B.; McSween, H. Y.

    2011-12-01

    Eruption of silicate lava, whether on Earth or another planet, requires that at some depth the melt has lower density than the surrounding rocks. As the densities of silicate liquids change during crystallization, whether a particular silicate liquid will erupt or be trapped at a level of neutral buoyancy is a complex yet fundamental issue for planetary dynamics. In general, 3 factors drive surface eruptions: inherent buoyancy relative to mantle phases, compositional evolution, and volatile contents. These factors manifest on Earth as terrestrial basalts commonly have compositions close to a density minimum [1]. Recent work has produced estimates of Martian parental magma compositions [2-5] based on shergottite meteorites and from Gusev crater. Using the MELTS algorithm [6] and other density calibrations, we simulated evolution of these liquids, focusing on density changes. For much of the crystallization path, density is controlled by FeO. All of the liquids begin with ρ ~ 2.8 g/cc at 1 bar, and the evolution of liquid density is controlled by the liquidus phases. At low pressures, olivine is the liquidus phase for each melt, and as FeO is not incompatible in olivine, olivine crystallization decreases liquid density, increasing buoyancy with crystallization. However, FeO is incompatible in pyroxene, and thus liquids crystallizing pyroxene become denser and less buoyant with crystallization, producing liquids with densities up to and above 3.0 g/cc. As the olivine-pyroxene saturation relationship is affected by pressure and chemistry, the identity of the liquidus phase and density evolution will vary between magmas. Without spreading centers, Mars has no location where the mantle approaches the surface, and it is likely that any magma which is denser than the crust will stall below or within that crust. The crystallization path of a liquid is a function of pressure, with pyroxene crystallizing first at P > 10 kbar (~80 km depth), close to the base of the Martian

  13. What Generated the Eruptive Tremor During the Bardarbunga Eruption, Iceland?

    NASA Astrophysics Data System (ADS)

    Eibl, Eva P. S.; Bean, Christopher J.; Vogfjörd, Kristin S.; Jónsdóttir, Ingibjörg; Höskuldsson, Armann; Þórðarson, Þorvaldur

    2016-04-01

    The Bárðarbunga eruption in Iceland 2014/15 led to the formation of a 85 km2 big lavafield and the extrusion of ~1.5 km3 of magma. The eruption initially started for 4 hours on August 29th. It stopped but restarted on the same fissure on August 31st. We installed a seismic array on August 30th. Harmonic tremor was seen on August 31st consistent with the visual opening of the fissure and continued through February 2015. The harmonic tremor with most energy from 0.8-1.5 Hz is remarkably stable over 6 months but 3 characteristic features occur from time to time: (i) Stronger harmonic tremor bursts in the same frequency range, (ii) Stronger non-harmonic bursts with energy up to 5 Hz and (iii) Step like increases or decreases in the tremor amplitude. Seemingly uncorrelated the array results show (iv) three very stable tremor directions until mid October and (v) tremor sources moving by up to 9 km in 4 days. We compare these five seismic observations with the features of the growing lavafield and discuss the relative importance of possible tremor sources such as: a resonating conduit, boiling magma in the vent, a resonating lavafield, interactions at the edges of the lavafield and inflation of the lavafield.

  14. Explosive eruptive activity and temporal magmatic changes at Yotei Volcano during the last 50,000 years, southwest Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Uesawa, Shimpei; Nakagawa, Mitsuhiro; Umetsu, Akane

    2016-10-01

    To understand the eruptive history, structure, and magmatic evolution of Yotei Volcano, southwest Hokkaido, Japan, we investigated the geology and petrology of tephras located around the base of the volcano. We identified 43 tephra units interbedded with soils (in descending stratigraphic order, tephras Y1-Y43), and four widespread regional tephras. Ten radiocarbon ages were obtained from soils beneath the Yotei tephras. On the basis of petrologic differences and, the stratigraphic positions of thick layers of volcanic ash soil, indicative of volcanic stratigraphic gaps, the Yotei tephras are divided into four groups (in ascending stratigraphic order): Yotei tephra groups I, II-1, II-2, and II-3. We calculated the age of each eruptive deposit based on the soil accumulation rate, and estimated the volume of each eruption using isopach maps or the correlation between eruption volume and the maximum thickness at ~ 10 km from the summit crater. The results regarding eruptive activity and the rate of explosive eruptions indicate four eruptive stages at Yotei Volcano over the last 50,000 years. Stage I eruptions produced Yotei tephra group I between ca. 54 cal. ka BP and up to at least ca. 46 cal. ka BP, at relatively high average eruption rates of 0.07 km3 dense-rock equivalent (DRE)/ky. After a pause in activity of ca. 8000 years, Stage II-1 to II-2 eruptions produced Yotei tephra groups II-1 and II-2 from ca. 38 to ca. 21 cal. ka BP at high average eruption rates (0.10 km3 DRE/ky), after a pause in activity of 2000-3000 years. Finally, after another pause in activity of 4000-5000 years, Stage II-3 eruptions produced Yotei tephra group II-3 from ca. 16.5 cal. ka BP until the present day, at low average eruption rates (0.009 km3 DRE/ky). Whole-rock geochemical compositions vary within each tephra group over the entire eruption history. For example, group I and II-3 tephras contain the lowest and highest abundances, respectively, of K2O, P2O5, and Zr. Group II-1 has the

  15. Tracking effusive eruptions in near real-time: 2014 Fogo (Cape Verde) eruption

    NASA Astrophysics Data System (ADS)

    Laiolo, Marco; Coppola, Diego; Cigolini, Corrado; Faria, Bruno; Ripepe, Maurizio

    2015-04-01

    The Fogo volcano (Cape Verde), after almost 20 years of inactivity, entered in a new effusive phase on November 23, 2014. The eruption occurred on the Fogo's Pico cone inside the Cha Caldera where the lava flow caused the evacuation of the Bangaeira and Portela inhabitants. To track the thermal evolution of this eruption, we extended the near-real time processing of the MIROVA (Middle InfraRed Observation of Volcanic Activity) algorithm to Fogo island. MIROVA is a hot-spot detection system based on the analysis of the Moderate Resolution Imaging Spectroradiometer (MODIS) data that provide thermal maps (1 km resolution) and radiant flux estimates, in near real time (1-4 hours from satellite overpass). Thermal output retrieved by MIROVA can be converted into time-average lava discharge rates allowing the identification of ongoing effusive trends. During the first 45 days of activity the eruption shows a waxing-waning trend typical of pressurized closed systems. Preliminary results indicate that MIROVA is particularly efficient to provide near real-time data that are critical for better assessing volcanic risk, and to help the decision-makers during volcanic crisis. Data requested by the UNDAC (United Nations Disaster Assessment and Coordination) team operating in Cape Verde, through the Emergency Response Coordination Center (ERCC) of the European Mechanism of Civil Protection, were provided in near real-time via web to the National Institute of Meteorology and Geophysics and to National Civil Protection. Once compared to seismological data, information provided by MIROVA have been successfully used during the volcanic crisis.

  16. [Burnout syndrome of human services professionals--doctors, nurses, caregivers, teachers and clerks (1). Maslach Burnout Inventory: factor structures for samples of human services professionals, and its relation with Zung's Self-rating Depression Scale (SDS)].

    PubMed

    Masuko, E; Yamagishi, M; Kishi, R; Miyake, H

    1989-07-01

    During the past decade, burnout syndrome has been widely discussed not only in the USA but also in Japan. To evaluate the state of "burnout," two major scales are available: the first is the Maslach Burnout Inventory (MBI) developed by C. Maslach and the other is the burnout scale by A. Pines. MBI is suggested to be independent of and incompatible with Pines' burnout scale, but, Pines' burnout scale is predominantly used in Japan, while both are used in the USA. Since hardly any studies of burnout using MBI have been made in Japan, we measured and analyzed MBI to evaluate the burnout state of doctors, nurses, caregivers, teachers and clerks who are engaged in "human services professions." The available data were subjected to factor analysis, reliability analysis and multiple regression analysis using Zung's Self-rating Depression Scale (SDS). The following results were obtained. 1) The factor analysis showed that the factor loading pattern was similar to that of Maslach's, but two different factors were emerged in addition to the standard factors in the intensity subscale. 2) In the relationship with the state of depression, burnout is closely related to depression but simultaneously has its own factors. This suggest that burnout is not a subtype of the depressive state.

  17. Desvenlafaxine prevents white matter injury and improves the decreased phosphorylation of the rate-limiting enzyme of cholesterol synthesis in a chronic mouse model of depression.

    PubMed

    Wang, Junhui; Qiao, Jinping; Zhang, Yanbo; Wang, Hongxing; Zhu, Shenghua; Zhang, Handi; Hartle, Kelly; Guo, Huining; Guo, Wei; He, Jue; Kong, Jiming; Huang, Qingjun; Li, Xin-Min

    2014-10-01

    Serotonin/norepinephrine reuptake inhibitors antidepressants exert their effects by increasing serotonin and norepinephrine in the synaptic cleft. Studies show it takes 2-3 weeks for the mood-enhancing effects, which indicate other mechanisms may underlie their treatment effects. Here, we investigated the role of white matter in treatment and pathogenesis of depression using an unpredictable chronic mild stress (UCMS) mouse model. Desvenlafaxine (DVS) was orally administrated to UCMS mice at the dose of 10 mg/kg/day 1 week before they went through a 7-week stress procedure and lasted for over 8 weeks before the mice were killed. No significant changes were found for protein markers of neurons and astrocytes in UCMS mice. However, myelin and oligodendrocyte-related proteins were significantly reduced in UCMS mice. DVS prevented the stress-induced injury to white matter and the decrease of phosphorylated 5'-AMP-activated protein kinase and 3-hydroxy-3-methyl-glutaryl-CoA reductase protein expression. DVS increased open arm entries in an elevated plus-maze test, sucrose consumption in the sucrose preference test and decreased immobility in tail suspension and forced swimming tests. These findings suggest that stress induces depression-like behaviors and white matter deficits in UCMS mice. DVS may ameliorate the oligodendrocyte dysfunction by affecting cholesterol synthesis, alleviating the depression-like phenotypes in these mice. We examined the possible role of oligodendrocyte and myelin in the pathological changes of depression with an unpredictable chronic mild stress (UCMS) mouse model. Oligodendrocyte-related proteins in the mouse brain were specifically changed during the stress period. The depressive-like behaviors and oligodendrocyte deficits could be prevented by the administration of desvenlafaxine. Oligodendrocyte and myelin may be an essential target of desvenlafaxine for the treatment of depression.

  18. Constraints on Determining the Eruption Style and Composition of Terrestrial Lavas from Space

    NASA Technical Reports Server (NTRS)

    Wright, Robert; Glaze, Lori; Baloga, Stephen M.

    2011-01-01

    The surface temperatures of active lavas relate to cooling rates, chemistry, and eruption style. We analyzed 61 hyperspectral satellite images acquired by the National Aeronautics and Space Administration s Earth Observing-1 (EO-1) Hyperion imaging spectrometer to document the surface temperature distributions of active lavas erupted at 13 volcanoes. Images were selected to encompass the range of common lava eruption styles, specifically, lava fountains, flows, lakes, and domes. Our results reveal temperature distributions for terrestrial lavas that correlate with composition (i.e., a statistically significant difference in the highest temperatures retrieved for mafic lavas and intermediate and felsic lavas) and eruption style. Maximum temperatures observed for mafi c lavas are approx.200 C higher than for intermediate and felsic lavas. All eruption styles exhibit a low-temperature mode at approx.300 C; lava fountains and 'a' a flows also exhibit a higher-temperature mode at approx.700 C. The observed differences between the temperatures are consistent with the contrasting rates at which the lava surfaces are thermally renewed. Eruption styles that allow persistent and pervasive thermal renewal of the lava surface (e.g., fractured crusts on channel-fed 'a' a flows) exhibit a bimodal temperature distribution; eruption styles that do not (e.g., the continuous skin of pahoehoe lavas) exhibit a single mode. We conclude that insights into composition and eruption style can only be gained remotely by analyzing a large spatio-temporal sample of data. This has implications for determining composition and eruption style at the Jovian moon Io, for which no in situ validation is available.

  19. Prenatal Depression Restricts Fetal Growth

    PubMed Central

    Diego, Miguel A.; Field, Tiffany; Hernandez-Reif, Maria; Schanberg, Saul; Kuhn, Cynthia; Gonzalez-Quintero, Victor Hugo

    2009-01-01

    Objective To identify whether prenatal depression is a risk factor for fetal growth restriction. Methods Midgestation (18-20 weeks GA) estimated fetal weight and urine cortisol and birth weight and gestational age at birth data were collected on a sample of 40 depressed and 40 non-depressed women. Estimated fetal weight and birthweight data were then used to compute fetal growth rates. Results Depressed women had a 13% greater incidence of premature delivery (Odds Ratio (OR) = 2.61) and 15% greater incidence of low birthweight (OR = 4.75) than non-depressed women. Depressed women also had elevated prenatal cortisol levels (p = .006) and fetuses who were smaller (p = .001) and who showed slower fetal growth rates (p = .011) and lower birthweights (p = .008). Mediation analyses further revealed that prenatal maternal cortisol levels were a potential mediator for the relationship between maternal symptoms of depression and both gestational age at birth and the rate of fetal growth. After controlling for maternal demographic variables, prenatal maternal cortisol levels were associated with 30% of the variance in gestational age at birth and 14% of the variance in the rate of fetal growth. Conclusion Prenatal depression was associated with adverse perinatal outcomes, including premature delivery and slower fetal growth rates. Prenatal maternal cortisol levels appear to play a role in mediating these outcomes. PMID:18723301

  20. Deformation of Grímsvötn volcano, Iceland, 1992-2014: Constraints on magma flow in relation to eruptions in 1998, 2004 and 2011

    NASA Astrophysics Data System (ADS)

    Sigmundsson, Freysteinn; Hreinsdottir, Sigrun; Sturkell, Erik; Ofeigsson, Benedikt; Einarsson, Pall; Roberts, Matthew; Grapenthin, Ronni; Villemin, Thierry; Arnadottir, Thora; Geirsson, Halldor

    2014-05-01

    A time series of ground deformation at Grímsvötn volcano, Iceland from 1992 to 2014 reveals deformation due to plate movements, glacial-isostatic uplift in response to the melting of the Vatnajökull ice cap, annual changes due to snow loading and magma movements. GPS measurements have been made at one nunatak, conducted intermittently since 1992 and continuously since 2004. During this period eruptions have occurred at Grímsvötn in 1998, 2004 and 2011. The component of displacement related to magma movements is obtained after the time series are corrected for signals due to other processes. Uplift and displacement away from the caldera occurs between eruptions at a rate of few cm/yr, interrupted by sudden co-eruptive subsidence and displacement towards the caldera (up to half a meter). This inflation/deflation pattern suggests deformation driven by pressure change in an upper crustal magma chamber, similar to other highly active calderas in Iceland such as Askja and Krafla. A simple model of pressure change variation in a magma chamber at shallow depth, with variable inflow between eruptions and outflow during eruptions can explain the observed deformation pattern. The erupted volume of magma in the 2011 eruption is about 10 times larger than the inferred co-eruptive volume change, attributed to compressibility of magma in the chamber. The magma compressibility is inferred to have remained constant during the 2011 eruption, as about constant scale factor is found during that eruption between eruption rate and displacement rate. This scale factor is, however, about five times lower for the 2004 eruption. This difference implies higher compressibility of magma in the shallow Grímsvötn magma chamber during the 2011 eruption compared to 2004, assuming the active part of the Grimsvötn magma plumbing system remained the same in both eruptions.

  1. Modelling of Subglacial Volcanic and Geothermal Activity, during the 2014-15 Bárdarbunga-Holuhraun Eruption and Caldera Collapse

    NASA Astrophysics Data System (ADS)

    Reynolds, H. I.; Gudmundsson, M. T.; Hognadottir, T.

    2015-12-01

    Seismic unrest was observed within the subglacial caldera of Bárdarbunga on 16 August 2014, followed by seismicity tracing the path of a lateral dyke extending underneath the Vatnajökull glacier out to 45 km to the north east of the volcano. A short subaerial fissure eruption occurred at the site of the Holuhraun lavas, just north of the glacier edge on 29 August, before recommencing in earnest on 31 August with a large effusive eruption and accompanying slow caldera collapse, which lasted for approximately 6 months. The glacier surface around Bárdarbunga was monitored using aerial altimeter profiling. Several shallow depressions, known as ice cauldrons, formed around the caldera rim and on Dyngjujökull glacier above the dyke propagation path. The cauldrons range in volume from approximately 0.0003 km3 to 0.02 km3. Two types of melting were observed: high initial heat flux over a period of days which gradually disappears; and slower but more sustained melting rates. We present time series data of the development and evolution of these cauldrons, with estimates of the heat flux magnitudes involved.The nature of the heat source required to generate these cauldrons is not obvious. Two scenarios are explored: 1) small subglacial eruptions; or 2) increased geothermal activity induced by the dyke intrusion. We investigate these scenarios using numerical modelling, considering the surface heat flux produced, and timescales and spatial extent of associated surface anomalies. It is found that a magmatic intrusion into rocks where the groundwater is near the boiling point curve can cause rapid increase in geothermal activity, but even a shallow intrusion into a cold groundwater reservoir will have a muted thermal response. Thus, our results indicate that minor subglacial eruptions are the most plausible explanation for the observed rapid melting far from known geothermal areas. These results have implications for the interpretation of thermal signals observed at ice

  2. Jupiter Eruptions Captured in Infrared

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

    Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

    This infrared image shows two bright plume eruptions obtained by the NASA Infrared Telescope Facility on April 5, 2007.

    Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

    According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vigorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  3. Herculaneum: Clues to Vesuvius eruption

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    More than 80 skeletons have been unearthed in the ancient Mediterranean town of Herculaneum, west of Italy's Mount Vesuvius. This anthropological find corroborates a reinterpretation by three University of Rhode Island scientists of the sequence of the August A.D. 79 eruption of Vesuvius. In addition, the discovery is the first proof that large numbers of people perished as they tried to flee from the eruption, estimated to have been about 10 times more powerful than the May 1980 Mount St. Helens blast.‘Who says dead men don't talk? Their bones have something to say about them and their everyday lives,’ says Sara C. Bisel, a physical anthropologist who analyzed the skeletons. Among the remains are a cluster of skeletons from six adults, four children, and two infants trying to shield themselves from the volcanic onslaught; the skeleton of a sailor, still clutching an oar, lying on his back beside an 8-m-long capsized boat; a woman whose now bony hand was still graced with gem-encrusted gold rings; and a soldier (see Figure 1). From these and other finds the anthropological team was able to discern that the ancient Romans, on average, were shorter than modern citizens and, judging from the condition of some of the teeth, probably had a low-sugar diet.

  4. SO2 flux and the thermal power of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Henley, Richard W.; Hughes, Graham O.

    2016-09-01

    A description of the dynamics, chemistry and energetics governing a volcanic system can be greatly simplified if the expansion of magmatic gas can be assumed to be adiabatic as it rises towards the surface. The conditions under which this assumption is valid are clarified by analysis of the transfer of thermal energy into the low conductivity wallrocks traversed by fractures and vents from a gas phase expanding over a range of mass flux rates. Adiabatic behavior is predicted to be approached typically within a month after perturbations in the release of source gas have stabilized, this timescale being dependent upon only the characteristic length scale on which the host rock is fractured and the thermal diffusivity of the rock. This analysis then enables the thermal energy transport due to gas release from volcanoes to be evaluated using observations of SO2 flux with reference values for the H2O:SO2 ratio of volcanic gas mixtures discharging through high temperature fumaroles in arc and mantle-related volcanic systems. Thermal power estimates for gas discharge are 101.8 to 104.1 MWH during quiescent, continuous degassing of arc volcanoes and 103.7 to 107.3 MWH for their eruptive stages, the higher value being the Plinean Pinatubo eruption in 1991. Fewer data are available for quiescent stage mantle-related volcanoes (Kilauea 102.1 MWH) but for eruptive events power estimates range from 102.8 MWH to 105.5 MWH. These estimates of thermal power and mass of gas discharges are commensurate with power estimates based on the total mass of gas ejected during eruptions. The sustained discharge of volcanic gas during quiescent and short-lived eruptive stages can be related to the hydrodynamic structure of volcanic systems with large scale gaseous mass transfer from deep in the crust coupled with episodes of high level intrusive activity and gas release.

  5. Response of a deciduous forest to the Mount Pinatubo eruption: enhanced photosynthesis.

    PubMed

    Gu, Lianhong; Baldocchi, Dennis D; Wofsy, Steve C; Munger, J William; Michalsky, Joseph J; Urbanski, Shawn P; Boden, Thomas A

    2003-03-28

    Volcanic aerosols from the 1991 Mount Pinatubo eruption greatly increased diffuse radiation worldwide for the following 2 years. We estimated that this increase in diffuse radiation alone enhanced noontime photosynthesis of a deciduous forest by 23% in 1992 and 8% in 1993 under cloudless conditions. This finding indicates that the aerosol-induced increase in diffuse radiation by the volcano enhanced the terrestrial carbon sink and contributed to the temporary decline in the growth rate of atmospheric carbon dioxide after the eruption.

  6. Mars: Review and analysis of volcanic eruption theory and relationships to observed landforms

    NASA Technical Reports Server (NTRS)

    Wilson, Lionel; Head, James W., III

    1994-01-01

    We present a theoretical treatment of the ascent, emplacement, and eruption of magma on Mars. Because of the lower gravity, fluid convective motions and crystal settling processes driven by positive and negative buoyancy forces, as well as overall diapiric ascent rates, will be slower on Mars than on Earth, permitting larger diapirs to ascend to shallower depths. Martian environmental conditions operate to modulate the various eruption styles and the morphology and morphometry of resulting landforms, providing new insight into several volcanological problems.

  7. One eruption every (half?) year - A remarkable recurrent nova in M31

    NASA Astrophysics Data System (ADS)

    Henze, Martin

    2016-07-01

    Recurrent Novae (RN) are those for which more than one eruption has been observed. Only ten RN are known in our Galaxy, while 17 such objects have been observed in the neighbouring Andromeda galaxy (M31). The object M31N 2008-12a stands out as a unique RN in M31 since it showed eight observed eruptions in the last eight years and has a suspected recurrence time between successive eruptions of only six months. Its eruption frequency is unparalleled: the recurrence time is at least an order of magnitude shorter than for the fastest Galactic RN, U Sco. Theoretical models predict M31N 2008-12a to have a WD mass close to the Chandrasekhar limit and a high accretion rate, making it the most promising candidate for a single-degenerate type Ia supernova progenitor known to date. For the first time, we can conduct statistical studies of repeated eruptions in an individual nova. I will present new results from the recent 2015 eruption and the early 2016 monitoring campaign. I will discuss these results in the context of the known eruption history and provide an outlook towards future observing plans and the ultimate fate of this remarkable nova.

  8. A numeral model to simulate the chemical processing of volcanic ejecta in eruption plumes and clouds

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, Gholam Ali; Hort, Marthias; Brasseur, Guy

    2016-04-01

    Volcanic eruptions inject tremendous amount of gases and particles into the atmosphere that can notably affect different components of the climate system. The scale of such impacts strongly depends on the eruption magnitude as well as the physicochemical properties of the erupted material, which are mainly shaped during the atmospheric transport within the eruption plume and cloud. For instance, the radiative forcing of an eruption through backscattering the incoming solar radiation depends on the amount and properties of the sulfate aerosols formed as the result of in-cloud processes including chemical conversion of volcanic SO2 to sulfate. The rate, pathway and efficiency of this conversion can therefore significantly influence the radiative forcing posed by the eruption. Models that can simulate such in-plume and in-cloud processes are rare. Here we present the framework and initial results of a numerical model that simulates the chemical interaction of gas, ash and aerosols within the volcanic eruption plumes and clouds. The chemical mechanism takes into account the gaseous and aqueous chemistry as well as the gas-aerosol partitioning within a fully-coupled scheme. In other words, it is capable of modeling the changes in the gas, liquid and solid phase separately as well as the interactions between phases. For instance, the results show that the ash dissolution reduces the acidity of its liquid coating and thus, enhances the scavenging of SO2 and HCl. The potential application of the model in volcanology, geochemistry and atmospheric sciences are discussed.

  9. Eruptive modes and