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Sample records for depressed eruption rate

  1. 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

  2. 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

  3. 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

  4. Satellite Based Extrusion Rates for the 2006 Augustine Eruption

    NASA Astrophysics Data System (ADS)

    Dehn, J.; Bailey, J. E.; Dean, K. G.; Skoog, R.; Valcic, L.

    2006-12-01

    Extrusion rates were calculated from polar orbiting infrared satellite data for the 2006 eruption of Augustine Volcano, Alaska. The pixel integrated brightness temperatures from the satellite data were converted to estimates of ground temperature by making assumptions and using first hand observations about the geometry of the hot area (lava dome, flows and pyroclastic flow deposits) relative to the cold area in the kilometer scale pixels. Extrusion rate is calculated by assuming that at a given temperature, a lava emits an amount of radiation proportional to its volume. On ten occasions during the activity, helicopter based infrared imagers were used to validate the satellite observations. The pre-January 11 thermal activity was not significantly above background in satellite data. The first strong thermal anomalies were recorded during the first explosive phase on January 11. During successive explosive phases in January, bright thermal signals were observed, often saturating the sensors. Large areas (many km2) were observed to be warm in the satellite data, indicative of pyroclastic flows. Sometime during or after January 29, during a phase of sustained ash emission, the thermal signal became persistent, suggesting the beginning of lava effusion. The extrusion rates derived from satellite data varied from 0 to nearly 7 m3/s, giving an eruption rate of 2.7 m3/s. The extrusion event produced two blocky lava flows which moved down the north flank of the volcano. Extrusion occurred through at least March 15 (day 76) when a sharp drop in extrusion rate and thermal signal is observed. Based on the derived extrusion rates, it is estimated that 18 million m3 of lava was extruded during the course of the eruption. This value agreed well with photogrammetric measurements, but does not agree with volumes derived through subtraction of digital elevation models post- and pre- eruption. It should be noted that the thermal approach only works for hot lavas, and does not

  5. Estimates of lava eruption rates at Alba Patera, Mars

    NASA Astrophysics Data System (ADS)

    Baloga, S. M.; Pieri, D. C.

    1985-04-01

    The Martian volcanic complex Alba Patera exhibits a suite of well-defined, long and relatively narrow lava flows qualitatively resembling those found in Hawaii. Even without any information on the duration of the Martian flows, eruption rates (total volume discharge/duration of the extrusion) estimates are implied by the physical dimensions of the flows and the likely conjecture that Stephan-Boltzmann radiation is the dominating thermal loss mechanism. The ten flows in this analysis emanate radially from the central vent and were recently measured in length, plan areas, and average thicknesses by shadow measurement techniques. The dimensions of interest are shown. Although perhaps morphologically congruent to certain Hawaiian flows, the dramatically expanded physical dimensions of the Martian flows argues for some markedly distinct differences in lava flow composition for eruption characteristics.

  6. 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.

  7. 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.

  8. 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)

  9. Voluminous eruption from a zoned magma body after an increase in supply rate at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Paduan, J. B.; Clague, D. A.; Dreyer, B. M.; Merle, S. G.; Bobbitt, A. M.; Caress, D. W.; Philip, B. T.; Kelley, D. S.; Nooner, S. L.

    2016-12-01

    Axial Seamount is the best monitored submarine volcano in the world, providing an exceptional window into the dynamic interactions between magma storage, transport, and eruption processes in a mid-ocean ridge setting. An eruption in April 2015 produced the largest volume of erupted lava since monitoring and mapping began in the mid-1980s after the shortest repose time, due to a recent increase in magma supply. The higher rate of magma replenishment since 2011 resulted in the eruption of the most mafic lava in the last 500-600 years. Eruptive fissures at the volcano summit produced pyroclastic ash that was deposited over an area of at least 8 km2. A systematic spatial distribution of compositions is consistent with a single dike tapping different parts of a thermally and chemically zoned magma reservoir that can be directly related to previous multichannel seismic-imaging results.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Geodesy - the key for constraining rates of magma supply, storage, and eruption

    NASA Astrophysics Data System (ADS)

    Poland, Michael; Anderson, Kyle

    2016-04-01

    Volcanology is an inherently interdisciplinary science that requires joint analysis of diverse physical and chemical datasets to infer subsurface processes from surface observations. Among the diversity of data that can be collected, however, geodetic data are critical for elucidating the main elements of a magmatic plumbing system because of their sensitivity to subsurface changes in volume and mass. In particular, geodesy plays a key role in determining rates of magma supply, storage, and eruption. For example, surface displacements are critical for estimating the volume changes and locations of subsurface magma storage zones, and remotely sensed radar data make it possible to place significant bounds on eruptive volumes. Combining these measurements with geochemical indicators of magma composition and volatile content enables modeling of magma fluxes throughout a volcano's plumbing system, from source to surface. We combined geodetic data (particularly InSAR) with prior geochemical constraints and measured gas emissions from Kīlauea Volcano, Hawai`i, to develop a probabilistic model that relates magma supply, storage, and eruption over time. We found that the magma supply rate to Kīlauea during 2006 was 35-100% greater than during 2000-2001, with coincident increased rates of subsurface magma storage and eruption at the surface. By 2012, this surge in supply had ended, and supply rates were below those of 2000-2001; magma storage and eruption rates were similarly reduced. These results demonstrate the connection between magma supply, storage, and eruption, and the overall importance of magma supply with respect to volcanic hazards at Kīlauea and similar volcanoes. Our model also confirms the importance of geodetic data in modeling these parameters - rates of storage and eruption are, in some cases, almost uniquely constrained by geodesy. Future modeling efforts along these lines should also seek to incorporate gravity data, to better determine magma

  15. 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.

  16. 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.

  17. Improvements on the relationship between plume height and mass eruption rate: Implications for volcanic ash cloud forecasting

    NASA Astrophysics Data System (ADS)

    Webley, P. W.; Dehn, J.; Mastin, L. G.; Steensen, T. S.

    2011-12-01

    Volcanic ash plumes and the dispersing clouds into the atmosphere are a hazard for local populations as well as for the aviation industry. Volcanic ash transport and dispersion (VATD) models, used to forecast the movement of these hazardous ash emissions, require eruption source parameters (ESP) such as plume height, eruption rate and duration. To estimate mass eruption rate, empirical relationships with observed plume height have been applied. Theoretical relationships defined by Morton et al. (1956) and Wilson et al. (1976) use default values for the environmental lapse rate (ELR), thermal efficiency, density of ash, specific heat capacity, initial temperature of the erupted material and final temperature of the material. Each volcano, based on its magma type, has a different density, specific heat capacity and initial eruptive temperature compared to these default parameters, and local atmospheric conditions can produce a very different ELR. Our research shows that a relationship between plume height and mass eruption rate can be defined for each eruptive event for each volcano. Additionally, using the one-dimensional modeling program, Plumeria, our analysis assesses the importance of factors such as vent diameter and eruption velocity on the relationship between the eruption rate and measured plume height. Coupling such a tool with a VATD model should improve pre-eruptive forecasts of ash emissions downwind and lead to improvements in ESP data that VATD models use for operational volcanic ash cloud forecasting.

  18. 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)...

  19. Current Use of Depression Rating Scales in Mental Health Setting

    PubMed Central

    Lee, Eun Jeong; Kim, Jung Bum; Shin, Im Hee; Lim, Kyung Hee; Lee, Sang Hee; Cho, Gyung Ah; Sung, Hyung Mo; Jung, Sung Won; Zmimmerman, Mark

    2010-01-01

    Objective This study was to investigate the current use of depression rating scales by psychiatrists and clinical psychologists in Korea. Methods The questionnaires from many psychiatrists and clinical psychologists were included in the analysis. The questionnaire was composed of items about examining the percentage of patients clinically using depression rating scales, reasons for not use of them, the degree of satisfaction, the perceived agreement rate between the result of depression rating scales and doctor's clinical interview in the evaluation of patients with depressive symptoms. Data were analyzed by χ2 and independent t-test. Results The clinical use of depression rating scales was more frequent in the psychologists than in the psychiatrists. The purposes for using depression rating scales were assessed into six areas, there was no significant difference in between two groups, and both groups pointed out their purpose as rating of severity and screening. The reasons for not using scales were that their interview may be sufficient for diagnosis and assessment of depressive patients and they are not familiar with the use of depression rating scales. The psychiatrists usually prefer the Beck Depression Inventory (BDI), Hamilton Depression Rating Scale and Symptom Checklist 90-Revision (SCL-90-R) in order of frequency, and the clinical psychologists are more likely to use the BDI, Minnesota Multiphasic Personality Inventory and SCL-90-R. Overall rate of satisfaction in the use of the scales was 67.29±14.45% and overall perceived agreement rate was 70.89±16.45%. Conclusion Currently used depression rating scales at the clinical practice were not various. Therefore, to heighten clinicians' utility of these depression rating scales measures, either educational efforts or advertisements, or both, will be necessary to spread them wildly. PMID:20927305

  20. 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.

  1. 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…

  2. High magma storage rates before the 1983 eruption of kilauea, hawaii

    PubMed

    Cayol; Dieterich; Okamura; Miklius

    2000-06-30

    After a magnitude 7.2 earthquake in 1975 and before the start of the ongoing eruption in 1983, deformation of Kilauea volcano was the most rapid ever recorded. Three-dimensional numerical modeling shows that this deformation is consistent with the dilation of a dike within Kilauea's rift zones coupled with creep over a narrow area of a low-angle fault beneath the south flank. Magma supply is estimated to be 0.18 cubic kilometers per year, twice that of previous estimates. The 1983 eruption may be a direct consequence of the high rates of magma storage within the rift zone that followed the 1975 earthquake.

  3. The 2011 Grímsvötn Eruption From High Rate Geodesy

    NASA Astrophysics Data System (ADS)

    Hreinsdottir, S.; Grapenthin, R.; Sigmundsson, F.; Roberts, M. J.; Holmjarn, J.; Geirsson, H.; Arnadottir, T.; Bennett, R. A.; Villemin, T.; Ofeigsson, B. G.; Sturkell, E. C.

    2011-12-01

    High rate geodetic measurements at volcanoes can give displacements at sub second intervals, revealing surface deformation associated with magma movements. The Grímsvötn volcano lies beneath the Vatnajökull icecap, Iceland, limiting the near field monitoring efforts to a single nunatak, Mt. Grímsfjall, on the southern caldera rim. A 5 Hz GPS station and an electronic tilt meter are located at Grímsfjall. The colocation of these instruments (GPS and tilt station) allows us to relate the observed surface deformation to pressure change in a magma chamber assuming a simple Mogi source within an elastic half space. During the 21-28 May 2011 Grímsvötn eruption a continuous stream of data, despite the eruption plume and lightning, was transmitted to Reykjavík. The tiltmeter measures N-S and E-W components of tilt, the N-S component was recorded at 100 samples per second (sps) but the E-W component at 4 sps. The high rate data from the GPS station at Grímsfjall (GFUM) were analyzed using the Track part of GAMIT/GLOBK. We produced kinematic solutions at 5 Hz and 1 Hz intervals using reference stations in 40-120 km distance of the volcano. To minimize multipath effects we applied sidereal filtering and stacked the individual solutions to further improve the signal to noise ratio. The resulting deformation time series suggests a rapid pressure drop starting about 50 minutes prior to the onset of the eruption when over 20 km high plume formed. The characteristics of the GPS and tilt data time series suggests that the main signal was induced by a single source of fixed location and geometry throughout the eruption; a shallow magma chamber. Small deviations in displacement direction prior to the onset of the eruption can be explained by the opening of the feeder dike. We see a total displacement of 57 cm in direction ˜N38.5°W and down at the GPS station, suggesting a source depth of ~1.7 km. About 20% of the displacement preceded the eruption and more than 95% took

  4. 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

  5. Rating scales measuring the severity of psychotic depression

    PubMed Central

    Østergaard, Søren D.; Rothschild, Anthony J.; Flint, Alastair J.; Mulsant, Benoit H.; Whyte, Ellen M.; Leadholm, Anne Katrine; Bech, Per; Meyers, Barnett S.

    2015-01-01

    Objective Unipolar psychotic depression (PD) is a severe and debilitating syndrome, which requires intensive monitoring. The objective of this study was to provide an overview of the rating scales used to assess illness severity in PD. Method Selective review of publications reporting results on non-self-rated, symptom-based rating scales utilized to measure symptom severity in PD. The clinical and psychometric validity of the identified rating scales was reviewed. Results A total of 14 rating scales meeting the predefined criteria were included in the review. These scales grouped into the following categories: I. Rating scales predominantly covering depressive symptoms, II. Rating scales predominantly covering psychotic symptoms, III. Rating scales covering delusions, and IV. Rating scales covering psychotic depression. For the vast majority of the scales, the clinical and psychometric validity had not been tested empirically. The only exception from this general tendency was the 11-item Psychotic Depression Assessment Scale (PDAS), which was developed specifically to assess the severity of PD. Conclusion In PD, the Psychotic Depression Assessment Scale (PDAS) represents the only empirically derived rating scale for the measurement of overall severity of illness. The PDAS should be considered in future studies of PD and in clinical practice. PMID:26016647

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

    PubMed

    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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Seismic and infrasonic eruption tremors and their relation to magma discharge rate: A case study for sub-Plinian events in the 2011 eruption of Shinmoe-dake, Japan

    NASA Astrophysics Data System (ADS)

    Ichihara, Mie

    2016-10-01

    Magma discharge rate is one of the most important parameters in quantifying volcanic activity. Many previous works have attempted to connect observations of seismic and infrasonic eruption tremors with magma discharge rate. Power law scaling relations with different power indices have been proposed based on various data sets and models. The 2011 eruption of Shinmoe-dake, Japan, provides an excellent data set with which to investigate these relationships for a sustained explosive eruption sequence. Magma discharge rates are well constrained by geodetic, geologic, and remote sensing methods. Seismic and infrasonic data were recorded close to the vent. Moreover, contributions to ground shaking from infrasound can be distinguished from seismic signals in the seismometer records. As a result, linear power law relationships are found to fit all pairs of variables (seismic eruption tremor power, infrasonic eruption tremor power, and magma discharge rate) in the quasi-stable or slowly growing stages of the sub-Plinian events. Similar relations have been reported for other eruptions but only between seismic eruption tremors and magma discharge rate or between seismic and infrasonic eruption tremors. Existing models do not fully explain the observed relationships. The possibility is proposed that Plinian-type eruptions generate both seismic and infrasonic eruption tremors by successive explosions at the fragmentation surface in the conduit; these linear relationships can therefore be observed only under conditions where flow and fragmentation in the conduit are stable.

  15. 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.

  16. 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

  17. Alteration of Heart Rate Variability in Patients of Depression

    PubMed Central

    Mondal, Sunita; Bandhu, Rajiv; Kataria, Dinesh; Gandhi, Asha

    2016-01-01

    Introduction Altered cardiac autonomic functions in form of reduced Heart Rate Variability (HRV) have been found to be associated with increased cardiovascular morbidity and mortality in depressive patients. Aim To investigate the relationship between HRV measures, which is a non-invasive marker of autonomic nervous system and depression. Materials and Methods The study included a convenient sample size of drug naive depressive patients (n=30) diagnosed on basis of ICD-10 and compared with age and gender matched healthy volunteers (n=30). Five minute ECG recording was done for HRV analysis and frequency domain measures like LF (Low Frequency), HF (High Frequency), LF/HF ratio as well as time domain measures like SDNN (Standard Deviation of all NN interval) and RMSSD (Root Mean Square of Successive differences of NN intervals) were obtained. Results In the frequency domain parameters, values of LF (nu) and LF/HF Ratio were found to be significantly higher (p<0.001) whereas, that of HF (nu) was significantly lower (p<0.001) in depression group as compared to control group. However, in the time domain parameters, no significant difference was observed in SDNN and RMSSD values in between the two groups. Conclusion HRV recordings showed significant changes in frequency domain parameters in the patients suffering from depression. Thus, it could be said from our study that autonomic imbalance reflecting enhanced sympathetic activation relative to parasympathetic component is associated with depression. PMID:28208852

  18. The effect of shortening incisor teeth on the eruption rates and lengths of the other incisors in the rat.

    PubMed

    Burn-Murdoch, R A

    1995-06-01

    The eruption rates and lengths of all four incisor teeth in rats were measured by recording the position of marks on their labial surfaces at 2-day intervals, using calibrated graticules in microscope eyepieces and ether anaesthesia. When one lower incisor, or both a lower and upper incisor, were unimpeded, the other lower incisor shortened markedly before the next measurement and the uppers slowly lengthened, so that the sum of the lengths of the lower and upper impeded incisors temporarily fell, then returned to control levels. The lower and upper impeded incisors showed temporary accelerations of their eruption when the other incisors were unimpeded. When an upper incisor was unimpeded, the lower incisors lengthened, increasing the sum of the lengths of the lower and upper impeded incisors, and the eruption of the lower and upper impeded incisors was slowed. When there were two impeded incisors in one jaw and only one (left) impeded incisor in the other jaw, the unopposed right impeded incisor tended to be slower and longer than its neighbour and there were significant correlations between the differences in eruption rates and differences in tooth lengths. In all these cases, there are negative relations between eruption and length; increases in length occur with decreases in eruption rate. The simplest explanation for this is that the length changes arise partly from the voluntary behaviour of the rat and also from mechanical problems due to having one impeded incisor in one jaw and two in the other jaw; the length changes cause the eruption-rate changes.

  19. The Validity and Utility of the Depression Proneness Rating Scale.

    ERIC Educational Resources Information Center

    Zemore, Robert; And Others

    The development of the Depression Proneness Rating Scale (DPRS) and three investigations into its reliability, validity, and factor structure are described. Subjects of all three studies were university undergraduates. The first study (n=100) found a stability coefficient of 0.82 for the DPRS over a test-retest (Time 1-Time 2) interval of 9 weeks.…

  20. 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…

  1. 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.

  2. 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.

  3. Human Life History Evolution Explains Dissociation between the Timing of Tooth Eruption and Peak Rates of Root Growth

    PubMed Central

    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

  4. 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,…

  5. 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

  6. 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

  7. 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.

  8. Magmatic storage conditions, decompression rate, and incipient caldera collapse of the 1902 eruption of Santa Maria Volcano, Guatemala

    NASA Astrophysics Data System (ADS)

    Andrews, Benjamin J.

    2014-08-01

    Phase equilibria experiments and analysis of natural pumice and phenocryst compositions indicate the 1902 Santa Maria dacite was stored at ~ 140-170 MPa and 840-850 °C prior to eruption. H2O-saturated, cold-seal experiments conducted in vessels with an intrinsic log fO2 of NNO + 1 ± 0.5 show that the natural phase assemblage (melt + plagioclase + amphibole + orthopyroxene + Fe-Ti oxides + apatite) is stable from approximately 115-140 MPa at temperatures below ~ 825 °C, to ~ 840-860 °C at 150 MPa, to > 850 and < 875 °C at 200 MPa. Natural plagioclase phenocrysts have rim compositions that range from An40-An45; this range of compositions defines a ~ 20 °C band that intersects the stable phase assemblage at ~ 150 MPa and 850 °C. Plagioclase hosted melt inclusions were analyzed using FTIR and commonly contain < 5 wt.% H2O, which corresponds to a pressure of ~ 170 MPa at 850 °C, under pure H2O saturated conditions. Amphibole geothermobarometry (Ridolfi et al., 2010) applied to experimental samples suggest two populations of amphiboles, phenocrysts grown during the experiments and inherited xenocrysts, but the pressure-temperature conditions returned by the geothermobarometer are routinely > 50 MPa and > 50 °C greater than experimental run conditions; precise estimates of magmatic conditions based solely upon amphibole composition are likely inaccurate. The experimental results and analysis of natural crystals suggest that although the natural amphiboles likely record a broad range of magmatic conditions, only the lower bounds of that range reflect pre-eruptive storage conditions. Comparison of Santa Maria microlite abundances with decompression experiments examining other silicic systems from the literature suggests that the 1902 dacite decompressed at the rate of ~ 0.005 to 0.01 MPa/s during the eruption. Applying the decompression rate with the previously described eruption rate of approximately 2-3 × 108 kg/s (Williams and Self, 1983; Carey and Sparks, 1986

  9. Rate of oxygen consumption in seasonal and non-seasonal depression.

    PubMed

    Pinchasov, Boris B; Grischin, Oleg V; Putilov, Arcady A

    2002-04-01

    Most depressives suffer from weight loss, anorexia and insomnia, while for winter depressives the typical symptoms are weight gain, carbohydrate craving, overeating, oversleeping and extreme lack of energy. It is important to know whether winter depressives differ from most other depressives on measures of energy regulation. In wintertime, we evaluated the rate of oxygen consumption in relationship to neuro-vegetative depressive symptoms in 92 Siberian women. The seated subjects underwent oxyspirography in the mid-morning (1.5 hours after a standard breakfast). It was found that the oxygen consumption rate was similar in non-depressed women (n = 25) and depressed women with non-seasonal depression (n = 27). The comparatively lower values were obtained in women with winter depression (n = 40). This finding supports the suggestion that the behaviour disturbances typical for winter depression may represent a physiological feedback loop to energy conservation.

  10. Comparison of physician-rating and self-rating scales for patients with major depressive disorder.

    PubMed

    Lin, Ching-Hua; Lu, Mei-Jou; Wong, Julielynn; Chen, Cheng-Chung

    2014-12-01

    Physician-rating scales remain the standard in antidepressant clinical trials. The current study aimed to examine the discrepancies between physician-rating scales and self-rating scales for symptoms and functioning, before and after treatment, in newly hospitalized patients. A total of 131 acutely ill inpatients with major depressive disorder were enrolled to receive 20 mg of fluoxetine daily for 6 weeks. Symptom severity and functioning were assessed at baseline and again at week 6. Symptom severity was rated using the 17-item Hamilton Depression Rating Scale (HDRS-17) and the Zung Self-rating Depression Scale (ZDS). Functioning was measured by the Global Assessment of Functioning (GAF) and the Work and Social Adjustment Scale (WSAS). Pearson correlation coefficients (r) between HDRS-17 and ZDS and between GAF and WSAS were calculated at week 0 and week 6. Sensitivity to change was measured using effect sizes. One-hundred twelve patients completed the 6-week trial. After 6 weeks of treatment, correlations between HDRS-17 and ZDS or correlations between GAF and WSAS became larger from baseline to end point. All correlations were statistically significant (P < 0.001). Effect sizes measured by physician-rating scales (ie, HDRS-17 and GAF) were larger than by self-rating scales (ie, ZDS and WSAS). Correlations between baseline physician-rating scale scores and self-rating scale scores improved after 6 weeks of treatment. Physician-rating scales had larger effect sizes than self-rating scales. Physician-rating scales were more sensitive in detecting symptom or functional changes than self-rating scales.

  11. 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

  12. Evaluation of depressive symptoms in patients with coronary artery disease using the Montgomery Åsberg Depression Rating Scale.

    PubMed

    Bunevicius, Adomas; Staniute, Margarita; Brozaitiene, Julija; Pommer, Antoinette M; Pop, Victor J M; Montgomery, Stuart A; Bunevicius, Robertas

    2012-09-01

    The aim of this study was to evaluate, in patients with coronary artery disease (CAD), factor structure and psychometric properties of the Montgomery Åsberg Depression Rating Scale (MADRS) to identify patients with current major depressive episode (MDE). The construct validity of the MADRS against self-rating scales was also evaluated. Consecutive 522 CAD patients at admission to the cardiac rehabilitation program were interviewed for the severity of depressive symptoms using the MADRS and for current MDE using the structured MINI International Neuropsychiatric Interview. Also, all patients completed the Hospital Anxiety and Depression Scale and the Beck Depression Inventory-II. The MADRS had one-factor structure and high internal consistency (Cronbach's coefficient α=0.82). Confirmative factor analysis indicated an adequate fit: comparative fit index=0.95, normed fit index=0.91, and root mean square error of approximation=0.07. At a cut-off value of 10 or higher, the MADRS had good psychometric properties for the identification of current MDE (positive predictive value=42%, with sensitivity=88% and specificity=85%). There was also a moderate to strong correlation of MADRS scores with scores on self-rating depression scales. In sum, in CAD patients undergoing rehabilitation, the MADRS is a unidimensional instrument with high internal consistency and can be used for the identification of depressed CAD patients. The association between MADRS and self-rating depression scores is moderate to strong.

  13. 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.

  14. Depression

    MedlinePlus

    ... version of this page please turn Javascript on. Depression About Depression Click for more information Depression is more than ... that contribute to depression. Is It Grief or Depression? Sometimes it can be difficult to distinguish grief ...

  15. The 2008 "silent" eruption of Nevados de Chillán (Chile) detected from space: Effusive rates and trends from the MIROVA system

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Laiolo, M.; Lara, L. E.; Cigolini, C.; Orozco, G.

    2016-11-01

    On January 2008, a "silent" eruption took place on the northeast flank of Nevados de Chillán volcanic complex (Chile). The eruption had an effusive character and persisted for several months during which a small lava field ( 0.12 km2) was emplaced. Although occurring at < 10 km from several mountain resorts, and < 70 km from Chillán city ( 150 k inhabitants) this eruption was completely unnoticed by local authorities and was only inferred a year after, based on field reconnaissance. However, the post processing of MODIS-derived thermal images, by means of the MIROVA system (Middle Infrared Observation of Volcanic Activity), revealed that the eruptive episode produced a clear and detectable thermal signal for the whole duration of the effusion. Based on the thermal flux and a sequence of Landsat images, we suggest that the eruption was fed by three distinct segments of an ENE-oriented dike and characterized by two main effusive phases. About 1.4 Mm3 of dacitic lava have been gently erupted (mean output rate of 0.075 m3 s- 1) without producing any evident manifestation (i.e. explosions, volcanic plumes, tremors, sounds) noticeable from distance. The results presented here demonstrate the capacity of thermal satellite data not only to detect but also to quantify the eruptive flux of a "silent" eruption, otherwise unreported.

  16. Observer-rated depression in long-term care: frequency and risk factors.

    PubMed

    McCusker, Jane; Cole, Martin G; Voyer, Philippe; Monette, Johanne; Champoux, Nathalie; Ciampi, Antonio; Vu, Minh; Dyachenko, Alina; Belzile, Eric

    2014-01-01

    The objectives of this study were: (1) to describe the prevalence and 6-month incidence of observer-rated depression in residents age 65 and over of long-term care (LTC) facilities; (2) to describe risk factors for depression, at baseline and over time. A multisite, prospective observational study was conducted in residents aged 65 and over of 7 LTC facilities. The Cornell Scale for Depression in Dementia (CSDD) was completed by nurses monthly for 6 months. We measured demographic, medical, and functional factors at baseline and monthly intervals, using data from research assessments, nurse interviews, and chart reviews. 274 residents were recruited and completed baseline depression assessments. The prevalence of depression (CSDD score of 6+) was 19.0%. The incidence of depression among those without prevalent depression was 73.3 per 100 person-years. A delirium diagnosis, pain, and diabetes were independently associated with prevalent depression. CSDD score at baseline and development of severe cognitive impairment at follow-up were independent risk factors for incident depression. A diagnosis of delirium and uncorrected visual impairment at follow-up occurred concurrently with incident depression. The results of this study have implications for the detection and prevention of depression in LTC. Delirium diagnosis, pain and diabetes at baseline were associated with prevalent depression; depression symptoms at baseline and development of severe cognitive impairment at follow-up were risk factors for incident depression.

  17. 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

  18. Seismic Moment Rate Function Inversions from Very Long Period Signals Associated with Strombolian Eruptions at Mount Erebus, Antarctica

    NASA Astrophysics Data System (ADS)

    Lucero, C.; Aster, R. C.; Borchers, B.; Kyle, P.

    2005-12-01

    Mount Erebus, Antarctica, shows persistent Strombolian activity, principally in the form of impulsive eruptions of simple and very large (up to 10 m diameter) gas bubbles through its long-lived phonolitic lava lake. Eruptions produce oscillatory near-field very long period (VLP; ~8-20 s period) seismic signals due to processes occurring (seconds) before, during, and (up to several minutes) following the characteristic bubble bursts that mark the onset of short period (>1 Hz) seismoacoustic signals. Coupled broadband seismoacoustic and video analysis shows that this signal is associated with three corresponding component processes: 1) the bubble ascent phase characterized by gas/lava mass transport within the conduit system that can produce a positive or negative vertical rate of momentum change, depending on the event; 2) the eruptive evisceration of the lava lake to a depth of up to 10's of m in the explosive surface decompression of the gas bubble; 3) the refilling and reestablishment gravitational equilibrium within the conduit system. We employ a new method for efficiently solving the inverse problem of finding either independent or proportional moment-tensor element rate functions using three-component near-field seismograms recorded at multiple seismic stations. The method incorporates a frequency-domain deconvolution that, in its most general formulation, solves for six independent moment rate tensor force couple time functions plus a vertical force time function. We present an efficient scheme for solving this problem using conjugate gradient methods and apply it to Erebus VLP signals from the past several years of activity.

  19. Eruptive history of a low-frequency and low-output rate Pleistocene volcano, Ciomadul, South Harghita Mts., Romania

    NASA Astrophysics Data System (ADS)

    Szakács, Alexandru; Seghedi, Ioan; Pécskay, Zoltán; Mirea, Viorel

    2015-02-01

    Based on a new set of K-Ar age data and detailed field observations, the eruptive history of the youngest volcano in the whole Carpathian-Pannonian region was reconstructed. Ciomadul volcano is a dacitic dome complex located at the southeastern end of the Călimani-Gurghiu-Harghita Neogene volcanic range in the East Carpathians. It consists of a central group of extrusive domes (the Ciomadul Mare and Haramul Mare dome clusters and the Köves Ponk dome) surrounded by a number of isolated peripheral domes, some of them strongly eroded (Bálványos, Puturosul), and others topographically well preserved (Haramul Mic, Dealul Mare). One of the domes (Dealul Cetăţii) still preserves part of its original breccia envelope. A large number of bread-crust bombs found mostly along the southern slopes of the volcano suggest that the dome-building activity at Ciomadul was punctuated by short Vulcanian-type explosive events. Two late-stage explosive events that ended the volcanic activity of Ciomadul left behind two topographically well-preserved craters disrupting the central group of domes: the larger-diameter, shallower, and older Mohoş phreatomagmatic crater and the smaller, deeper and younger Sf. Ana (sub)Plinian crater. Phreatomagmatic products of the Mohoş center, including accretionary lapilli-bearing base-surge deposits and poorly sorted airfall deposits with impact sags, are known close to the eastern crater rim. A key section studied in detail south of Băile Tuşnad shows the temporal succession of eruptive episodes related to the Sf. Ana (sub)Plinian event, as well as relationships with the older dome-building stages. The age of this last eruptive event is loosely constrained by radiocarbon dating of charcoal pieces and paleosoil organic matter at ca. 27-35 ka. The age of the Mohoş eruption is not constrained, but we suggest that it is closely related to the Sf. Ana eruption. The whole volcanic history of Ciomadul spans over ca. 1 Myr, starting with the building

  20. Phenylthiocarbamide tasting and family history of depression, revisited: low rates of depression in families of supertasters.

    PubMed

    Joiner, Thomas E; Perez, Marisol

    2004-04-15

    Past studies suggest that phenylthiocarbamide (PTC) taste status is related to vulnerability to depression, such that those sensitive to PTC are more vulnerable. We questioned this, reasoning that those insensitive to PTC may be more vulnerable (because they may have lower hedonic tone and higher risk for alcohol abuse). Forty-two volunteers responded to questionnaires regarding family history of depression, and were assigned to supertaster, taster, or non-taster categories based on taste reactions to a 3.80 x 1.43 cm piece of commercially prepared paper treated with PTC. Supertasters were significantly less likely to report first-degree relatives with a history of depression than were tasters and non-tasters. Supertasters may be afforded some protection from depression; elucidating the mechanisms of this protection is a potentially interesting avenue for future research.

  1. Rates and risk factors associated with depressive symptoms during pregnancy and with postpartum onset.

    PubMed

    Verreault, Nancy; Da Costa, Deborah; Marchand, André; Ireland, Kierla; Dritsa, Maria; Khalifé, Samir

    2014-09-01

    The objectives of this study were to evaluate the prevalence of depressive symptoms in the third trimester of pregnancy and at 3 months postpartum and to prospectively identify risk factors associated with elevated depressive symptoms during pregnancy and with postpartum onset. About 364 women attending antenatal clinics or at the time of their ultrasound were recruited and completed questionnaires in pregnancy and 226 returned their questionnaires at 3 months postpartum. Depressed mood was assessed by the Edinburgh Postnatal Depression Scale (EPDS; score of ≥ 10). The rate of depressed mood during pregnancy was 28.3% and 16.4% at 3 months postpartum. Among women with postpartum depressed mood, 6.6% were new postpartum cases. In the present study, belonging to a non-Caucasian ethnic group, a history of emotional problems (e.g. anxiety and depression) or of sexual abuse, comorbid anxiety, higher anxiety sensitivity and having experienced stressful events were associated with elevated depressed mood during pregnancy. Four risk factors emerged as predictors of new onset elevated depressed mood at 3 months postpartum: higher depressive symptomatology during pregnancy, a history of emotional problems, lower social support during pregnancy and a delivery that was more difficult than expected. The importance of identifying women at risk of depressed mood early in pregnancy and clinical implications are discussed.

  2. Emergence of depression following job loss prospectively predicts lower rates of reemployment.

    PubMed

    Stolove, Catherine A; Galatzer-Levy, Isaac R; Bonanno, George A

    2017-03-22

    Job loss has been associated with the emergence of depression and subsequent long-term diminished labor market participation. In a sample of 500 adults who lost their jobs, trajectories of depression severity from four years before to four years after job loss were identified using Latent Growth Mixture Modeling. Rates of unemployment by trajectory were compared at two and four years following job loss. Four trajectories demonstrated optimal model fit including resilience (72%), chronic pre-to-post job loss depression (9%), emergent depression (10%), and remitting depression (9%). Logistic regression comparing reemployment status by class while controlling for age, gender, and education at two-years post job loss revealed no significant differences by class. An identical logistic regression on four-year reemployment revealed significant differences by class with post-hoc analyses revealing emergent depression resulting in a 33.3% reemployment rate compared to resilient individuals (60.4%) together indicating that depression affects reemployment rather than lack of reemployment causing the emergence of depression. The emergence of depression following job loss significantly increases the risk of continued unemployment. However, observed high rates of resilience with resulting downstream benefits in reemployment mitigates significant concern about the effects of wide spread unemployment on ongoing global economic recovery following the Great Recession.

  3. 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

  4. NanoSIMS results from olivine-hosted melt embayments: Modeling ascent rate in explosive basaltic eruptions

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    A critical parameter governing the explosivity of volcanic eruptions is the rate at which magma ascends and degases, because this affects bubble nucleation, coalescence, and ultimately fragmentation. Although several methods have been used to determine magma ascent rates, it remains a poorly constrained parameter for most eruptions. One promising method employs diffusion modeling of H2O and CO2 concentration gradients in melt embayments/open melt inclusions [1,2]. Here we utilize the fine spatial resolution of the nanoSIMS to obtain concentration gradients for five volatile species, improving upon previous efforts that were more limited in spatial resolution (FTIR, [1]) and in number of volatile analytes (H2O only by BSE, [2]). Focusing on explosive basaltic eruptions, for which very little is known about ascent rates, we chose ash and lapilli samples from the Oct 1974 sub-plinian eruption of Volcán de Fuego. Glassy, olivine-hosted embayments with evidence of outlet bubbles were analyzed by nanoSIMS at a minimum distance between spots of 15 μm. Major element zonation in the embayments was investigated by EMP, and high resolution BSE images were captured to complement the nanoSIMS spot measurements for H2O (as in [2]). We report analyses for 5 embayments that vary in length from 100 to 350 μm. Low-solubility volatiles (CO2, H2O, S) decrease towards the embayment outlet, consistent with diffusive reequilibration with the more-degassed surrounding melt. High-solubility volatiles (Cl, F) increase towards the outlet, apparently behaving as magmaphile elements. Major elements exhibit constant concentrations along the embayment, except for a 20-50 μm wide zone near the embayment outlet, perhaps representing a boundary layer at the outlet bubble, where concentrations vary consistent with olivine and clinopyroxene microlite growth. BSE grayscale values are thus affected by both H2O diffusion and major element zonation at the embayment outlet, and cannot be used to

  5. 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

  6. Depression rating scales in Parkinson's disease: A critical review updating recent literature.

    PubMed

    Torbey, Elizabeth; Pachana, Nancy A; Dissanayaka, Nadeeka N W

    2015-09-15

    Depression is a prominent non-motor symptom in Parkinson's disease (PD). Assessing depression in PD remains a challenge due to the overlap of somatic symptoms between depression and PD. Other neuropsychiatric manifestations associated with PD, such as cognitive decline, also complicate assessment of depression. Therefore it is critical to investigate the validity of depression rating scales for use in PD. This will allow evaluation of observer- and self-report instruments to be administered in neurologically ill geriatric populations such as PD, and identification of appropriate scales to use in cognitively challenged PD patients. The present review includes all studies examining the validity of depression rating scales in PD. It discusses the usefulness of 13 depression rating scales in PD. The clinician-rated and widely used HAMD-17 and the self-report GDS scales are recommended for screening and measuring severity of depression in PD. The GDS-15 may be a preferred choice due to its brevity and ease of use design for older adults. Other valid and reliable instruments to use in PD include self-rated scales, such as the HADS-D, HDI, and the BDI, and the observer-report, MADRS. The CSDD displayed satisfactory validity and reliability for identification of PD patients with and without dementia. The PHQ-2, PHQ-10, SDS, CES-D, UPDRS-Depression item, IDS-SR, and IDS-C each showed some evidence of validity or reliability, however further research on the psychometric properties of these scales when used in a PD population are required.

  7. Depression and Anxiety Following Aneurysmal Subarachnoid Hemorrhage Are Associated With Higher Six-Month Unemployment Rates.

    PubMed

    Al Yassin, Altaib; Ouyang, Bichun; Temes, Richard

    2017-01-01

    Although survival has dramatically improved following aneurysmal subarachnoid hemorrhage (aSAH), the reasons for persistent high rates of unemployment in this population remain unknown. Retrospective review for medical records of patients with aSAH admitted to Rush University Medical Center was undertaken. Multivariate logistic regression models were used to test the association of either depression or anxiety with the 6-month employment status. Among the 29 patients who developed depression or anxiety, 86.2% were unemployed at 6 months following their aSAH. After controlling for confounding factors, anxiety and depression were significantly associated with higher 6-month unemployment rates (odds ratio [OR]=0.08, 95% confidence interval [CI]=0.02-0.3, p=0.0002). Depression and anxiety are common following aSAH and are associated with increased unemployment rates 6 months post aSAH.

  8. 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

  9. Sensitivity to detect change and the correlation of clinical factors with the Hamilton Depression Rating Scale and the Beck Depression Inventory in depressed inpatients.

    PubMed

    Schneibel, Rebecca; Brakemeier, Eva-Lotta; Wilbertz, Gregor; Dykierek, Petra; Zobel, Ingo; Schramm, Elisabeth

    2012-06-30

    Discrepancies between scores on the Hamilton Depression Rating Scale (HAMD) and the Beck Depression Inventory (BDI), as well as differences regarding their sensitivity to detect change, have been reported. This study investigates discrepancies and their potential prediction on the basis of demographic, personality, and clinical factors in depressed inpatients and analyzes the sensitivity to change. The HAMD and the BDI were administered to 105 inpatients with major depressive disorder randomized to 5 weeks of either interpersonal psychotherapy or clinical management. Personality was assessed with the NEO Five-Factor Inventory. Low extraversion and high neuroticism were associated with relatively higher endorsement of depressive symptoms on the BDI compared with the HAMD. The HAMD presented a greater reduction of symptom scores than the BDI. Patients with high BDI scores, high HAMD scores or both revealed the greatest change, possibly due to a statistical effect of regression to the mean. Restricted by sample size, analyses were not differentiated by treatment condition. Regression to the mean cannot be tested directly, but it might be considered as a possible explanation. The HAMD and the BDI should be regarded as two complementary rather than redundant or competing instruments as the discrepancy is associated with personality characteristics. Attributing large effect sizes solely to effective treatment and a sensitive measure may be misleading.

  10. Depressants

    MedlinePlus

    ... of depressants, including alcohol and the illegal drugs GHB and Rohypnol , come in liquid or powder form ... by prescription only. Some depressants, including Rohypnol and GHB, are illegal in the United States. Illegal possession ...

  11. Depression

    MedlinePlus

    ... There are a variety of causes, including genetic, biological, environmental, and psychological factors. Depression can happen at ... are effective treatments for depression, including antidepressants, talk therapy, or both. NIH: National Institute of Mental Health

  12. Depression

    MedlinePlus

    ... the winter months, when there is less natural sunlight. Return to top What causes depression? There is ... alone. Others with moderate to severe depression might benefit from antidepressants. It may take a few weeks ...

  13. Depression

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003213.htm Depression - overview To use the sharing features on this page, please enable JavaScript. Depression may be described as feeling sad, blue, unhappy, ...

  14. Depression

    MedlinePlus

    ... is in crisis, get help quickly. Reprints Share Depression Basics Download PDF Download ePub Order a free ... a serious but treatable mood disorder. What is depression? Everyone feels sad or low sometimes, but these ...

  15. Validity of depression rating scales during pregnancy and the postpartum period: impact of trimester and parity.

    PubMed

    Ji, Shuang; Long, Qi; Newport, D Jeffrey; Na, Hyeji; Knight, Bettina; Zach, Elizabeth B; Morris, Natalie J; Kutner, Michael; Stowe, Zachary N

    2011-02-01

    The objective of the current study was to delineate the optimal cutpoints for depression rating scales during pregnancy and the postpartum period and to assess the perinatal factors influencing these scores. Women participating in prospective investigations of maternal mental illness were enrolled prior to 28 weeks gestation and followed through 6 months postpartum. At each visit, subjects completed self-rated depression scales--Edinburgh Postnatal Depression Scale (EPDS) and Beck Depression Inventory (BDI) and clinician-rated scales--Hamilton Rating Scale for Depression (HRSD(17) and HRSD(21)). These scores were compared to the SCID Mood Module for the presence of fulfilling diagnostic criteria for a major depressive episode (MDE) during 6 perinatal windows: preconception; first trimester; 2nd trimester; 3rd trimester; early postpartum; and later postpartum. Optimal cutpoints were determined by maximizing the sum of each scale's sensitivity and specificity. Stratified ROC analyses determined the impact of previous pregnancy and comparison of initial to follow-up visits. A total of 534 women encompassing 640 pregnancies and 4025 follow-up visits were included. ROC analysis demonstrated that all 4 scales were highly predictive of MDE. The AUCs ranged from 0.857 to 0.971 and were all highly significant (p < .0001). Optimal cutpoints were higher at initial visits and for multigravidas and demonstrated more variability for the self-rated scales. These data indicate that both clinician-rated and self-rated scales can be effective tools in identifying perinatal episodes of major depression. However, the results also suggest that prior childbirth experiences and the use of scales longitudinally across the perinatal period influence optimal cutpoints.

  16. 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.

  17. 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.

  18. A Comparison of Self-Rated and Female Partner-Rated Scales in the Assessment of Paternal Prenatal Depression.

    PubMed

    Konishi, Mizuho; Tachibana, Yoshiyuki; Tang, Julian; Takehara, Kenji; Kubo, Takahiko; Hashimoto, Keiji; Kitazawa, Hiroshi; Saito, Hirohisa; Ohya, Yukihiro

    2016-11-01

    Maternal depression has been widely studied but paternal depression is often overlooked. Depression in men is generally more difficult to detect as the symptoms are not apparent. Furthermore, Japanese couples tend to suppress their real emotions to avoid confrontation. We aimed to investigate the reliability and validity of the K6, K10 and PHQ-9 in assessing the mental health status of men when used by their pregnant partners, as well as the prevalence of paternal prenatal depression in a Japanese study sample. A total of 136 couples participated in this study. The prevalence of paternal prenatal depression reported by the men themselves was higher compared to that reported by their female partners (K6, 10.3 %; K10, 6.6 %; PHQ-9, 3.7 % vs. K6-FP, 2.2 %; K10-FP, 1.5 %; PHQ-9-FP, 0 %, respectively). Mental health issues in men may not be accurately rated by their female partners, suggesting the importance of self-rating and direct consultation.

  19. Executive function moderates the relationship between depressive symptoms and resting heart rate variability in heart failure.

    PubMed

    Gathright, Emily C; Walter, Fawn A; Hawkins, Misty A W; Spitznagel, Mary Beth; Hughes, Joel W; Gunstad, John

    2016-04-01

    Heart failure (HF) is associated with high rates of depression. In turn, depression is associated with reduced heart rate variability (HRV), a marker of parasympathetic dysfunction and poorer cardiac outcomes. Cognitive impairment--especially executive dysfunction--is also highly prevalent in HF, but it is unknown whether executive function (EF) impacts the depression-HRV relationship. The primary objective of this paper is to examine whether EF moderates the relationship between depression and HRV in HF. Participants were 109 HF patients. Depressive symptoms were measured using the Beck Depression Inventory-II. EF was assessed using a composite of age-adjusted T scores on the Frontal Assessment Battery, Trail Making Test B, and Stroop Color Word subtest. Parasympathetic function was assessed using resting high frequency HRV (HF-HRV). Multiple hierarchical regression was used to conduct BDI × EF moderation analyses. BDI scores were associated with reduced resting HF-HRV (p < .05). No main effects were detected between EF and resting HF-HRV (p > .05). However, EF moderated the relationship between BDI scores and resting HF-HRV (β = 0.59, p < .01). Simple slope analyses revealed that among participants with poorer EF, higher BDI scores were associated with lower resting HF-HRV (p < .001). Structural brain changes common in HF may contribute to lower EF, increased depression, and poorer autonomic functioning. Alternatively, the results may indicate that individuals with intact EF engage in self-care strategies that negate the detrimental impact of depression on autonomic function. Additional work is needed to clarify these possibilities and the potential benefits of treating depression in HF patients with different cognitive abilities.

  20. 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.

  1. 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

  2. Effect of inbreeding depression on outcrossing rates among populations of a tropical pine.

    PubMed

    Del Castillo, R F; Trujillo, S

    2008-01-01

    Inbreeding depression is common among plants and may distort mating system estimates. Mating system studies traditionally ignore this effect, nonetheless an assessment of inbreeding depression that may have occurred before progeny evaluation could be necessary. In the neotropical Pinus chiapensis inbreeding depression was evaluated using regression analysis relating progeny F-values with seed germinability, the mating system was analysed in three populations with contrasting size, using isozymes, obtained a corrected outcrossing rate. Selfing decreased seed viability by 19%, relative to an outcrossed plant. Multilocus outcrossing rates, t(m), varied widely among populations. In the two smallest populations t(m) congruent with 1. Therefore, inbreeding depression did not affect the estimates, but overestimated t(m) by 10% in the third population, which has a true mixed mating system (selfing was the major source of inbreeding), and an unusually low t(m) for pines (t(m) = 0.54, uncorrected, t(m) = 0.49, corrected). Inbreeding depression may be an uneven source of bias for outcrossing estimates even at the infraspecific level. Accuracy [corrected] but not precision [corrected] may be gained by including inbreeding depression in outcrossing estimates. Therefore, caution should be taken when comparing t(m) among species or even populations within the same species.

  3. Depression: Problem-solving appraisal and self-rated health among Hong Kong Chinese migrant women.

    PubMed

    Chow, Susan K Y; Chan, Wing Chi

    2010-09-01

    This cross-sectional survey explored the depression status of new migrant women and its relationship with self-rated health in the Hong Kong Chinese context. A convenience sample of 68 migrant women volunteered to participate in the study. The data were collected by using the Problem Solving Inventory, the Center for Epidemiological Studies-Depression questionnaire, and a self-rated health scale. The respondents were found to have a lesser degree of problem-solving appraisal, compared with other populations, and almost half of the volunteers were found to be depressed. Approximately 50% of the women reported their general health as "excellent", "very good", or "good". The Pearson's correlation showed a positive significant correlation between problem-solving appraisal, depression, and self-rated health. The results of the regression analysis showed that family income, self-rated health, and problem-solving confidence are predictive factors of depression. Community nurses could consider using multidisciplinary interventions that focus on life-skills training in order to promote the psychological and general wellness of migrant women in addition to the use of counseling or medication interventions.

  4. Daily Mood Ratings via Text Message as a Proxy for Clinic Based Depression Assessment

    PubMed Central

    Aguilera, Adrian; Schueller, Stephen; Leykin, Yan

    2015-01-01

    Background Mobile and automated technologies are increasingly becoming integrated into mental healthcare and assessment. The purpose of this study was to determine how automated daily mood ratings are related to the Patient Health Questionnaire–9 (PHQ-9), a standard measure in the screening and tracking of depression symptoms. Results There was a significant relationship between daily mood scores and one-week average mood scores and PHQ-9 scores controlling for linear change in depression scores. PHQ9 scores were not related to the average of two week mood ratings. This study also constructed models using variance, maximum, and minimum values of mood ratings in the preceding week and two-week periods as predictors of PHQ-9. None of these variables significantly predicted PHQ-9 scores when controlling for daily mood ratings and the corresponding averages for each period. Limitations This study only assessed patients who were in treatment for depression therefore do not account for the relationship between text message mood ratings for those who are not depressed. The sample was also predominantly Spanish speaking and low-income making generalizability to other populations uncertain. Conclusions Our results show that automatic text message based mood ratings can be a clinically useful proxy for the PHQ9. Importantly, this approach avoids the limitations of the PHQ9 administration, which include length and a higher requirement for literacy. PMID:25679202

  5. 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

  6. 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.

  7. New-onset depression following stable, slow, and rapid rate of prescription opioid dose escalation.

    PubMed

    Salas, Joanne; Scherrer, Jeffrey F; Schneider, Frank David; Sullivan, Mark D; Bucholz, Kathleen K; Burroughs, Thomas; Copeland, Laurel A; Ahmedani, Brian K; Lustman, Patrick J

    2017-02-01

    Recent studies suggest that longer durations of opioid use, independent of maximum morphine equivalent dose (MED) achieved, is associated with increased risk of new-onset depression (NOD). Conversely, other studies, not accounting for duration, found that higher MED increased probability of depressive symptoms. To determine whether rate of MED increase is associated with NOD, a retrospective cohort analysis of Veterans Health Administration data (2000-2012) was conducted. Eligible patients were new, chronic (>90 days) opioid users, aged 18 to 80, and without depression diagnoses for 2 years before start of follow-up (n = 7051). Mixed regression models of MED across follow-up defined 4 rate of dose change categories: stable, decrease, slow increase, and rapid increase. Cox proportional hazard models assessed the relationship of rate of dose change and NOD, controlling for pain, duration of use, maximum MED, and other confounders using inverse probability of treatment-weighted propensity scores. Incidence rate for NOD was 14.1/1000PY (person-years) in stable rate, 13.0/1000PY in decreasing, 19.3/1000PY in slow increasing, and 27.5/1000PY in rapid increasing dose. Compared with stable rate, risk of NOD increased incrementally for slow (hazard ratio = 1.22; 95% confidence interval: 1.05-1.42) and rapid (hazard ratio = 1.58; 95% confidence interval: 1.30-1.93) rate of dose increase. Faster rates of MED escalation contribute to NOD, independent of maximum dose, pain, and total opioid duration. Dose escalation may be a proxy for loss of control or undetected abuse known to be associated with depression. Clinicians should avoid rapid dose increase when possible and discuss risk of depression with patients if dose increase is warranted for pain.

  8. 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…

  9. [The ICD-10 Symptom Rating (ISR): validation of the depression scale in a clinical sample].

    PubMed

    Brandt, Wolfram Alexis; Loew, Thomas; von Heymann, Friedrich; Stadtmüller, Godehard; Georgi, Alexander; Tischinger, Michael; Strom, Frederik; Mutschler, Friederike; Tritt, Karin

    2015-06-01

    The ICD-10 Symptom Rating (ISR) 1 measures the severity of psychiatric disorders with 29 items on 5 subscales as comprehensively as possible. The following syndromes are measured: Depressive syndrome, anxiety syndrome, obsessive-compulsive syndrome, Somatoform syndrome, eating disorder syndrome as well as additional items that cover various mental syndromes, and an overall score. The study reports findings on the validity and sensitivity to change of the depression subscale (ISR-D). In a clinical sample of N=949 inpatients with depression spectrum disorders the convergent validity was determined by correlation with the Beck Depression Inventory (BDI) 3 and the subscale "depression" of the Symptom-Checklist-90-R (SCL-90-R) 4. The high correlation between the different instruments confirms the validity of the ISR-Depression Scale. The sensitivity to change of the ISR seems higher than that of the BDI and the SCL-90. Because of its economy and the good psychometric properties the ISR is recommended for use in clinical samples.

  10. 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

  11. 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

  12. Prevalence Rates of Depression, Anxiety, and Somatization among Rural Southwestern Native American Children.

    ERIC Educational Resources Information Center

    Morris, Carolyn T.; Morris, Christopher; Crowley, Susan L.

    Internalizing symptoms, which include anxiety and depression, may be the most common pattern of psychopathology found in children. However, the knowledge base targeting internalizing symptomology in Native American children of the Southwest is surprisingly limited. This paper reports on a study of prevalence rates of internalizing disorders among…

  13. One-Year Prevalence Rates of Major Depressive Disorder in First-Year University Students

    ERIC Educational Resources Information Center

    Price, E. Lisa; McLeod, Peter J.; Gleich, Stephen S.; Hand, Denise

    2006-01-01

    First-year university students may be more at risk for experiencing Major Depressive Disorder (MDD) than the general population given associated risk factors of this age range. A two-phase procedure was used to estimate the one-year prevalence rate of MDD and comorbid Major Anxiety Disorders among first-year university students at a small Canadian…

  14. Plasma neurotransmitters, blood pressure, and heart rate during supine-resting, orthostasis, and moderate exercise conditions in major depressed patients.

    PubMed

    Lechin, F; van der Dijs, B; Orozco, B; Lechin, M E; Báez, S; Lechin, A E; Rada, I; Acosta, E; Arocha, L; Jiménez, V

    1995-08-01

    Major depressed patients showed greater heart rate, noradrenaline, and free-serotonin values than normal. Conversely, platelet-serotonin values in major depressed patients were significantly lower than normal. Patients registered the normal differential blood pressure reduction during orthostasis. They also revealed progressive and significantly higher heart rate rises during orthostasis and exercise periods, when compared to normals. Whereas noradrenaline showed maximal rises during the two last periods, adrenaline only showed small but significant increase during exercise. The analysis of correlations, together with the above data, suggests that major depressed patients register maximal neural sympathetic activity as well as adrenal glands sympathetic hypoactivity. In addition, these patients show hyperparasympathetic activity, as reflected by the free-serotonin profile. Finally, the fact that both the Hamilton Depression Rating Scale and the self-rating Beck Depression Inventory correlated positively with noradrenaline/adrenaline ratio and free-serotonin values strongly suggests that both neural sympathetic and cholinergic mechanisms are involved in major depression.

  15. Evaluating and monitoring treatment response in depression using measurement-based assessment and rating scales.

    PubMed

    Trivedi, Madhukar H

    2013-07-01

    Even with many treatment options available for major depressive disorder, many patients fail to achieve remission and return to their presymptomatic levels of functioning at work, in leisure activities, and in relationships. Throughout treatment, clinicians should implement measurement-based care by systematically monitoring patients' response using self-rated scales, such as the PHQ-9, QIDS-SR, or BDI. By tracking depressive symptoms, as well as suicidality, treatment adherence, and side effects, clinicians can adjust treatment to help patients achieve the best outcomes. Measurement-based care enables clinicians to make informed decisions at critical points throughout the treatment process and to involve patients in making those decisions.

  16. Depressants

    MedlinePlus

    ... with other drugs to add to the other drugs ’ high or to deal with their side effects. Abusers take higher doses than people taking the drugs under a doctor ’ s supervision for therapeutic purposes. Depressants ...

  17. Heart rate variability and depressed mood in physical education students: a longitudinal study.

    PubMed

    Pichon, Aurélien; Nuissier, Frédéric; Chapelot, Didier

    2010-08-25

    Autonomic nervous system (ANS) activity, and more specifically its parasympathetic component, has been reported to be associated with depression. The objective of this longitudinal study was to assess whether changes in heart rate variability (HRV) and in depressive moods were interrelated in healthy young subjects. Thirty students in physical education with a high physical load, were followed over the university year at 3 periods: October (P1), February (P2) and May (P3). Depressive mood was assessed by the score on the Depression subscale of the profile of mood state (POMS) questionnaire. HRV was assessed in supine and during an active orthostatic test with total power (TPms(2)) as the sum of the very low (VLF), low (LF) and high frequency (HF) bands, LF/HF ratio representing sympathetic and HFms(2) parasympathetic modulations. Results showed that changes in Depression scores between P1 and P2 were negatively and positively associated with changes in TPms(2), LFms(2), and HFms(2) in supine position and during orthostatism respectively. Although Anger/Aggressivity, Fatigue, and Vigor scores of the POMS were also correlated with changes in some HRV indices, Depression was the only significant predictive factor of changes in TPms(2) and HFms(2) between P1 and P2 in supine position and during orthostatism. These results were not observed between P2 and P3. In conclusion, in a healthy young sample of population, changes in depressive moods are associated with changes in total rhythmical power of HRV and more specifically its parasympathetic component.

  18. 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…

  19. Semantic Organizational Strategy Predicts Verbal Memory and Remission Rate of Geriatric Depression

    PubMed Central

    Morimoto, Sarah Shizuko; Gunning, Faith M.; Kanellopoulos, Dora; Murphy, Christopher F.; Klimstra, Sibel A.; Kelly, Robert E.; Alexopoulos, George S.

    2011-01-01

    OBJECTIVE This study tests the hypothesis that the use of a semantic organizational strategy, during the free recall phase of a verbal memory task predicts remission of geriatric depression. METHODS 65 elderly patients with major depression participated in a 12-week escitalopram treatment trial. Neuropsychological performance was assessed at baseline after a 2-week drug washout period. The Hopkins Verbal Learning Test-Revised (HVLT-R)(Brandt 2001) was used to assess verbal learning and memory. Remission was defined as a Hamilton Depression Rating Scale Score (HDRS) less than or equal to 7 for two consecutive weeks and no longer meeting DSM-IV-TR criteria for major depression. The association between the number of clusters used at the final learning trial (Trial 3) and remission was examined using Cox’s proportional hazards survival analysis. The relationship between the number of clusters utilized in the final learning trial and words recalled after a 25 minute delay was examined in a regression with age and education as covariates. RESULTS Greater number of clusters utilized predicted remission rate (Hazard ratio (95% CI) = 1.26 (1.04–1.54), χ2 =4.23, df=3, p=0.04). There was a positive relationship between the total number of clusters used by the end of the third learning trial and the total number of words recalled at the delayed recall trial (F(3,58)=7.93;p<.001) CONCLUSIONS Effective semantic strategy use at baseline on a verbal list learning task by elderly depressed patients was associated with greater rate of remission with antidepressant treatment. This result provides support for previous findings indicating that measures of executive functioning at baseline are useful in predicting antidepressant response. PMID:21618287

  20. The effect of metabolic depression on proton leak rate in mitochondria from hibernating frogs.

    PubMed

    St-Pierre, J; Brand, M D; Boutilier, R G

    2000-05-01

    Futile cycling of protons across the mitochondrial inner membrane accounts for 20 % or more of the total standard metabolic rate of a rat. Approximately 15 % of this total is due to proton leakage inside the skeletal muscle alone. This study examined whether the rate of proton leak is down-regulated as a part of a coordinated response to energy conservation during metabolic depression in cold-submerged frogs. We compared the proton leak rate of skeletal muscle mitochondria isolated from frogs at different stages of hibernation (control, 1 month and 4 months of submergence in normoxia and hypoxia). The kinetics of mitochondrial proton leak rate was unaltered throughout normoxic and hypoxic submergence. The state 4 respiration rates did not differ between control animals and frogs hibernating in normoxia. In contrast, the state 4 respiration rates obtained from frogs submerged in hypoxic water for 4 months were half those of control animals. This 50 % reduction in respiration rate in hypoxic hibernation was due to a reduction in electron transport chain activity and consequent decrease in mitochondrial membrane potential. We conclude that proton leak rate is reduced during metabolic depression as a secondary result of a decrease in electron transport chain activity, but that the proton conductance is unchanged. In addition, we show that the rate of proton leakage and the activity of the electron transport chain are lower in frogs than in rats, strengthening the observation that mitochondria from ectotherms have a lower proton conductance than mitochondria from endotherms.

  1. 40Ar/39Ar dating, geochemistry, and isotopic analyses of the quaternary Chichinautzin volcanic field, south of Mexico City: implications for timing, eruption rate, and distribution of volcanism

    NASA Astrophysics Data System (ADS)

    Arce, J. L.; Layer, P. W.; Lassiter, J. C.; Benowitz, J. A.; Macías, J. L.; Ramírez-Espinosa, J.

    2013-12-01

    Monogenetic structures located at the southern and western ends of the Chichinautzin volcanic field (Trans-Mexican Volcanic Belt, Central Mexico) yield 40Ar/39Ar ages ranging from 1.2 Ma in the western portion of the field to 1.0-0.09 Ma in the southern portion, all of which are older than the <0.04 Ma age previously established for the entire volcanic field. These new ages indicate: (1) an eruption rate of 0.47 km3/kyr, which is much lower than the 11.7 km3/kyr previously estimated; (2) that the Chichinautzin magmatism coexisted with the Zempoala (0.7 Ma) and La Corona (1.0 Ma) polygenetic volcanoes on the southern edge of Las Cruces Volcanic Range (Trans-Mexican Volcanic Belt); and confirm (3) that the drainage system between the Mexico and Cuernavaca basins was closed during early Pleistocene forming the Texcoco Lake. Whole-rock chemistry and Sr, Nd, and Pb isotopic data indicate heterogeneous magmatism throughout the history of Chichinautzin activity that likely reflects variable degrees of slab and sediment contributions to the mantle wedge, fractional crystallization, and crustal assimilation. Even with the revised duration of volcanism within the Chichinautzin Volcanic Field, its eruption rate is higher than most other volcanic fields of the Trans-Mexican Volcanic Belt and is comparable only to the Tacámbaro-Puruaran area in the Michoacán-Guanajuato Volcanic Field to the west. These variations in eruption rates among different volcanic fields may reflect a combination of variable subduction rates of the Rivera and Cocos plates along the Middle America Trench, as well as different distances from the trench, variations in the depth with respect to the subducted slab, or the upper plate characteristics.

  2. Creeping eruption

    MedlinePlus

    ... JavaScript. Creeping eruption is a human infection with dog or cat hookworm larvae (immature worms). Causes Hookworm eggs are found in the stool of infected dogs and cats. When the eggs hatch, the larvae ...

  3. Depressants

    MedlinePlus

    ... crime punishable by hefty fines and jail time. How Can Someone Quit? Quitting depressants can be very difficult. A person who tries to stop taking the drugs can have tremors, breathing problems, and seizures, go into a coma, or even die. Because the body's systems get used to the ...

  4. The self-reported Montgomery-Åsberg depression rating scale is a useful evaluative tool in major depressive disorder

    PubMed Central

    Fantino, Bruno; Moore, Nicholas

    2009-01-01

    Background The use of Patient-reported Outcomes (PROs) as secondary endpoints in the development of new antidepressants has grown in recent years. The objective of this study was to assess the psychometric properties of the 9-item, patient-administered version of the Montgomery-Åsberg Depression Rating Scale (MADRS-S). Methods Data from a multicentre, double-blind, 8-week, randomised controlled trial of 278 outpatients diagnosed with Major Depressive Disorder were used to evaluate the validity, reliability and sensitivity to change of the MADRS-S using psychometric methods. A Receiver Operating Characteristic (ROC) curve was plotted to identify the most appropriate threshold to define perceived remission. Results No missing values were found at the item level, indicating good acceptability of the scale. The construct validity was satisfactory: all items contributed to a common underlying concept, as expected. The correlation between MADRS-S and physicians' MADRS was moderate (r = 0.54, p < 0.001) indicating that MADRS-S is complementary rather than redundant to the MADRS. Cronbach's alpha was 0.84, and the stability over time of the scale, estimated on a sub-sample of patients whose health status did not change during the first week of the study, was good (intraclass correlation coefficient of 0.78). MADRS-S sensitivity to change was shown. Using a threshold value of 5, the definition of "perceived remission" reached a sensitivity of 82% and a specificity of 75%. Conclusion Taking account of patient's perceptions of the severity of their own symptoms along with the psychometric properties of the MADRS-S enable its use for evaluative purposes in the development of new antidepressant drugs. PMID:19473506

  5. 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

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

    PubMed

    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.

  7. Depression.

    PubMed

    McCarron, Robert M; Vanderlip, Erik R; Rado, Jeffrey

    2016-10-04

    This issue provides a clinical overview of depression, focusing on screening, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  8. Atypical reactivity of heart rate variability to stress and depression across development: Systematic review of the literature and directions for future research.

    PubMed

    Hamilton, Jessica L; Alloy, Lauren B

    2016-12-01

    Heart rate variability has received growing attention in the depression literature, with several recent meta-analyses indicating that lower resting heart rate variability is associated with depression. However, the role of fluctuations in heart rate variability (or reactivity) in response to stress in depression remains less clear. The present review provides a systematic examination of the literature on heart rate variability reactivity to a laboratory-induced stressor task and depression, including 26 studies of reactivity in heart rate variability and clinical depression, remitted (or history of) depression, and subthreshold depression (or symptom-level depression) among adults, adolescents, and children. In addition to reviewing the findings of these studies, methodological considerations and conceptual gaps in the literature are addressed. We conclude by highlighting the importance of investigating the potential transactional relationship between heart rate variability reactivity and depression and possible mechanisms underlying this relationship.

  9. 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.…

  10. The large and destructive 1669 AD eruption at Etna volcano: reconstruction of the lava flow field evolution and effusion rate trend

    NASA Astrophysics Data System (ADS)

    Branca, Stefano; De Beni, Emanuela; Proietti, Cristina

    2013-02-01

    The 1669 AD flank eruption was the most destructive event on Etna volcano in historical times (˜700 BC) and provided, because of the presence of numerous quarries and subsurface data, the opportunity for a unique case study in which we directly measured the thickness of the lava field. Moreover, analysis of historical documents allowed reconstruction of the temporal evolution of the lava field and estimation of the average effusion rate. One hundred and thirty-eight thickness measurements, acquired from field surveys and subsurface data, allowed us to divide the lava field into 12 zones of homogenous mean thickness and to calculate a total lava volume of (607 ± 105) × 106 m3, corresponding to an average effusion rate of 58 ± 10 m3/s. This new volume differs by -24 % up to +64 %, from previously published values. The temporal evolution of the cumulative volume and average effusion rate were reconstructed for the first fourteen days, from field data and analysis of historical records. A short initial phase was characterized by a rapid increase in effusion rate, which reached a peak of ˜640 m3/s after 3 days. This was followed by a longer phase in which the flow rate decreased. The first 14 days were crucial for the development of the lava field, and in this time it covered 72 % of its final area and produced most of the damage. Thereafter, the growth of a complex lava tube network promoted lava field lengthening to the city of Catania, 17 km away from the vent. Effusion rate trends like those of the 1669 eruption can be adopted for future investigations aimed at assessing the effects of similar events on Etna's most highly urbanized area and at other effusive basaltic volcanoes.

  11. 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

  12. 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.

  13. Rates and predictors of depression status among caregivers of patients with COPD hospitalized for acute exacerbations: a prospective study

    PubMed Central

    Bernabeu-Mora, Roberto; García-Guillamón, Gloria; Montilla-Herrador, Joaquina; Escolar-Reina, Pilar; García-Vidal, José Antonio; Medina-Mirapeix, Francesc

    2016-01-01

    Background Hospitalization is common for acute exacerbation of COPD, but little is known about its impact on the mental health of caregivers. Objective The aim of this study was to determine the rates and predictors of depressive symptoms in caregivers at the time of hospitalization for acute exacerbation of COPD and to identify the probability and predictors of subsequent changes in depressive status 3 months after discharge. Materials and methods This was a prospective study. Depression symptoms were measured in 87 caregivers of patients hospitalized for exacerbation at hospitalization and 3 months after discharge. We measured factors from four domains: context of care, caregiving demands, caregiver resources, and patient characteristics. Univariate and multivariate multiple logistic regressions were used to determine the predictors of depression at hospitalization and subsequent changes at 3 months. Results A total of 45 caregivers reported depression at the time of hospitalization. After multiple adjustments, spousal relationship, dyspnea, and severe airflow limitation were the strongest independent predictors of depression at hospitalization. Of these 45 caregivers, 40% had a remission of their depression 3 months after discharge. In contrast, 16.7% of caregivers who were not depressive at hospitalization became depressive at 3 months. Caregivers caring >20 hours per week for patients with dependencies had decreased odds of remission, and patients having dependencies after discharge increased the odds of caregivers becoming depressed. Conclusion Depressive symptoms are common among caregivers when patients are hospitalized for exacerbation of COPD. Although illness factors are determinants of depression at hospitalization, patient dependence determines fluctuations in the depressive status of caregivers. PMID:28008245

  14. 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

  15. 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.

  16. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Ukstins Peate, I.; Bryan, S. E.; Peate, D. W.; Self, S.; Mawby, M.; Jerram, D. A.; Marsh, J.

    2010-12-01

    Large igneous provinces (LIPs) host the most frequently recurring, largest volume basaltic & silicic eruptions on Earth. Understanding magma volumes, eruptive mechanisms, frequency and aerosol emissions are critical to interpret climate forcing and environmental change. The largest volume (>1000 km3 dre) and magnitude (>M8) eruptions produce areally extensive (104-105 km2) basaltic flow fields and silicic ignimbrites that are the main building blocks of LIPs. Magma volumes >1000 km3 are also emplaced as high-level basaltic and rhyolitic sills in LIPs, and may contribute substantial aerosol emissions through shallow degassing and crystallization. Basaltic and silicic eruptions have comparable magnitudes, but silicic ignimbrite volumes may be significantly underestimated due to unrecognized and correlated, but voluminous co-ignimbrite ash deposits. Magma composition appears to be no barrier to individual eruption volume. Despite similar magnitudes, flood basaltic and silicic eruptions are very different in eruption mechanism, duration, intensity, vent configuration, and emplacement style. Flood basalts are dominantly effusive Hawaiian-Strombolian, with magma discharge rates of ~107-108 kg/s, and produce dominantly compound pahoehoe flow fields over eruption durations most likely >10 yrs. Some large-volume silicic lavas were emplaced by effusive and fissure eruptions, but discharge rates are unknown and may be up to an order of magnitude greater than those of flood basalt lavas for emplacement to be on realistic time scales (<10 years). Most silicic eruptions are moderately to highly explosive, producing co-current pyroclastic fountains (rarely Plinian) with discharge rates of 109-1011 kg/s that emplace welded to rheomorphic ignimbrites. Stratospheric ash and aerosol injections may be greater from co-ignimbrite ash clouds than eruption plumes. At present, durations for large-magnitude silicic eruptions are unconstrained. At discharge rates of 109 kg/s, equivalent to

  17. 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

  18. Translating effects of inbreeding depression on component vital rates to overall population growth in endangered bighorn sheep.

    PubMed

    Johnson, Heather E; Mills, L Scott; Wehausen, John D; Stephenson, Thomas R; Luikart, Gordon

    2011-12-01

    Evidence of inbreeding depression is commonly detected from the fitness traits of animals, yet its effects on population growth rates of endangered species are rarely assessed. We examined whether inbreeding depression was affecting Sierra Nevada bighorn sheep (Ovis canadensis sierrae), a subspecies listed as endangered under the U.S. Endangered Species Act. Our objectives were to characterize genetic variation in this subspecies; test whether inbreeding depression affects bighorn sheep vital rates (adult survival and female fecundity); evaluate whether inbreeding depression may limit subspecies recovery; and examine the potential for genetic management to increase population growth rates. Genetic variation in 4 populations of Sierra Nevada bighorn sheep was among the lowest reported for any wild bighorn sheep population, and our results suggest that inbreeding depression has reduced adult female fecundity. Despite this population sizes and growth rates predicted from matrix-based projection models demonstrated that inbreeding depression would not substantially inhibit the recovery of Sierra Nevada bighorn sheep populations in the next approximately 8 bighorn sheep generations (48 years). Furthermore, simulations of genetic rescue within the subspecies did not suggest that such activities would appreciably increase population sizes or growth rates during the period we modeled (10 bighorn sheep generations, 60 years). Only simulations that augmented the Mono Basin population with genetic variation from other subspecies, which is not currently a management option, predicted significant increases in population size. Although we recommend that recovery activities should minimize future losses of genetic variation, genetic effects within these endangered populations-either negative (inbreeding depression) or positive (within subspecies genetic rescue)-appear unlikely to dramatically compromise or stimulate short-term conservation efforts. The distinction between

  19. Polymorphic light eruption sine eruption.

    PubMed

    Dover, J S; Hawk, J L

    1988-01-01

    We describe seven patients, four female and three male, who developed intense pruritus on sun-exposed skin without visible change. The clinical features resembled those of polymorphic light eruption (PLE) without rash. Four patients also occasionally developed typical PLE upon sun exposure, but sun-induced pruritus alone occurred most frequently. No patient was taking any drug therapy. One patient developed similar pruritus following solar simulated irradiation, and one following PUVA therapy. All other laboratory investigations were negative. Treatment with low dose UVB phototherapy or PUVA therapy was effective. The condition, which we have called polymorphic light eruption sine eruptione (PLESE), appears to be a variant of PLE not previously reported.

  20. Seasonality of Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

    An analysis of volcanic activity in the last three hundred years reveals that the frequency of onset of volcanic eruptions varies systematically with the time of year. We analysed the Smithsonian catalogue of more than 3200 subaerial eruptions recorded during the last 300 years. We also investigated continuous records, which are not part of the general catalogue, of individual explosions at Sakurajima volcano (Japan, 150 events per year since 1955) and Semeru (Indonesia, 100,000 events during the period 1997-2000). A higher proportion (as much as 18 percent of the average monthly rate) of eruptions occur worldwide between December and March. This observation is statistically significant at above the 99 percent level. This pattern is independent of the time interval considered, and emerges whether individual eruptions are counted with equal weight or with weights proportional to event explosivity. Elevated rates of eruption onset in boreal winter months are observed in northern and southern hemispheres alike, as well as in most volcanically-active regions including, most prominently, the 'Ring of Fire' surrounding the Pacific basin. Key contributors to this regional pattern include volcanoes in Central and South America, the volcanic provinces of the northwest Pacific rim, Indonesia and the southwest Pacific basin. On the smallest spatial scales, some individual volcanoes for which detailed histories exist exhibit peak levels in eruption activity during November-January. Seasonality is attributed to one or more mechanisms associated with the annual hydrological cycle, and may correspond to the smallest time-scale over which fluctuations in stress due to the redistribution of water-masses are felt by the Earth's crust. Our findings have important ramifications for volcanic risk assessment, and offer new insight into possible changes in volcanic activity during periods of long-term changes in global sea level.

  1. Seasonality of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Mason, B.; Pyle, D.; Dade, B.; Jupp, T.

    2003-04-01

    An analysis of volcanic activity in the last three hundred years reveals that the frequency of onset of volcanic eruptions varies systematically with the time of year. We analysed the Smithsonian catalogue of more than 3200 subaerial eruptions recorded during the last 300 years. We also investigated continuous records, which are not part of the general catalogue, of individual explosions at Sakurajima volcano (Japan, 150 events per year since 1955) and Semeru (Indonesia, 100,000 events during the period 1997-2000). A higher proportion (as much as 18 percent of the average monthly rate) of eruptions occur worldwide between December and March. This observation is statistically significant at above the 99 percent level. This pattern is independent of the time interval considered, and emerges whether individual eruptions are counted with equal weight or with weights proportional to event explosivity. Elevated rates of eruption onset in boreal winter months are observed in northern and southern hemispheres alike, as well as in most volcanically-active regions including, most prominently, the 'Ring of Fire' surrounding the Pacific basin. Key contributors to this regional pattern include volcanoes in Central and South America, the volcanic provinces of the northwest Pacific rim, Indonesia and the southwest Pacific basin. On the smallest spatial scales, some individual volcanoes for which detailed histories exist exhibit peak levels in eruption activity during November-January. Seasonality is attributed to one or more mechanisms associated with the annual hydrological cycle, and may correspond to the smallest time-scale over which fluctuations in stress due to the redistribution of water-masses are felt by the Earth's crust. Our findings have important ramifications for volcanic risk assessment, and offer new insight into possible changes in volcanic activity during periods of long-term changes in global sea level.

  2. Concordance between clinician and patient ratings as predictors of response, remission, and recurrence in major depressive disorder

    PubMed Central

    Dunlop, Boadie W.; Li, Thomas; Kornstein, Susan G.; Friedman, Edward S.; Rothschild, Anthony J.; Pedersen, Ron; Ninan, Philip; Keller, Martin; Trivedi, Madhukar H.

    2013-01-01

    We conducted a secondary analysis of data from the Prevention of Recurrent Episodes of Depression With Venlafaxine Extended Release (ER) for Two Years (PREVENT) trial to evaluate whether discrepancies between clinician and patient ratings of depression severity were predictive of response, remission, and recurrence during treatment for a depressive episode. Patients who self-rated depression severity in concordance with the clinician (“concordant patients”) were defined as having a standardized patient-rated Inventory of Depressive Symptoms-Self Report (IDS-SR30) score minus standardized clinician-rated Hamilton Rating Scale for Depression (HAM-D17) score <1 SD from mean. Non-concordant patients (“underrating patients” [−1 SD], “overrating patients” [+1 SD]) were identified. Cohorts were compared for remission and response on the HAM-D17, Clinician Global Impression–Severity (CGI-S), and IDS-SR30 during acute and continuation therapy and time to recurrence during maintenance therapy. During acute treatment female patients were more likely to overrate their depression severity compared to the clinician; older age predicted overrating during continuation treatment. Overrating patients had a slower onset of response on the HAM-D17 during acute treatment (P = 0.004). There were no differences between cohorts for remission or response on the HAM-D17 or CGI-S. Overrating patients at week 10 had lower remission and response rates on the IDS-SR30 during continuation therapy (32% and 50%, respectively; P ≤ 0.001) compared with underrating patients (76%, 77%) or concordant patients (64%, 78%). Patient concordance at the end of continuation therapy did not predict recurrence during maintenance therapy, indicating that patient rating scales may be useful in tracking recurrence during maintenance therapy. Poor agreement between patient- and clinician-ratings of depression severity is primarily a state phenomenon, although it is trait-like for some patients

  3. 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

  4. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Bryan, Scott; Peate, David; Ukstins Peate, Ingrid; Self, Stephen; Mawby, Michael; Jerram, Dougal; Marsh, Goonie

    2010-05-01

    Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. The magma volumes, eruptive mechanisms, frequency and associated aerosol emissions of these eruptions are critical for understanding any interpreted climate forcing and environmental change by LIPs. The largest volume (>1000 km3 dense rock equivalent) and magnitude (>M8) eruptions produce areally extensive (104-105 km2) basaltic lava flow fields and silicic ignimbrites and 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- 2,000 km3) silicic lava flows have also been mapped out in the Mesoproterozoic Gawler Range province (Australia), an interpreted LIP remnant. Magma volumes of >1000 km3 have also been emplaced as high-level basaltic and rhyolitic sills in LIPs, and may contribute substantial aerosol emissions through shallow degassing and crystallisation. 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 ~107-108 kg s-1 producing dominantly compound pahoehoe lava flow fields. The major flood basalt eruption durations are most

  5. A Bayesian method for the joint estimation of outcrossing rate and inbreeding depression.

    PubMed

    Koelling, V A; Monnahan, P J; Kelly, J K

    2012-12-01

    The population outcrossing rate (t) and adult inbreeding coefficient (F) are key parameters in mating system evolution. The magnitude of inbreeding depression as expressed in the field can be estimated given t and F via the method of Ritland (1990). For a given total sample size, the optimal design for the joint estimation of t and F requires sampling large numbers of families (100-400) with fewer offspring (1-4) per family. Unfortunately, the standard inference procedure (MLTR) yields significantly biased estimates for t and F when family sizes are small and maternal genotypes are unknown (a common occurrence when sampling natural populations). Here, we present a Bayesian method implemented in the program BORICE (Bayesian Outcrossing Rate and Inbreeding Coefficient Estimation) that effectively estimates t and F when family sizes are small and maternal genotype information is lacking. BORICE should enable wider use of the Ritland approach for field-based estimates of inbreeding depression. As proof of concept, we estimate t and F in a natural population of Mimulus guttatus. In addition, we describe how individual maternal inbreeding histories inferred by BORICE may prove useful in studies of inbreeding and its consequences.

  6. Eruptive xanthomas.

    PubMed

    Zaremba, Joanna; Zaczkiewicz, Andrzej; Placek, Waldemar

    2013-12-01

    Xanthomas are localized lipid deposits in the skin, tendons and subcutaneous tissue associated with lipid abnormality. The hyperlipidemia responsible for this disorder can be caused by a primary genetic defect, a secondary disorder, or both. That kind of skin exanthema may be the first signal of cardiovascular risk. We present a 24-year-old woman with a skin eruption that had appeared a few months earlier.

  7. Eruptive xanthomas

    PubMed Central

    Zaczkiewicz, Andrzej; Placek, Waldemar

    2013-01-01

    Xanthomas are localized lipid deposits in the skin, tendons and subcutaneous tissue associated with lipid abnormality. The hyperlipidemia responsible for this disorder can be caused by a primary genetic defect, a secondary disorder, or both. That kind of skin exanthema may be the first signal of cardiovascular risk. We present a 24-year-old woman with a skin eruption that had appeared a few months earlier. PMID:24494004

  8. Depression and resting state heart rate variability in children and adolescents - A systematic review and meta-analysis.

    PubMed

    Koenig, Julian; Kemp, Andrew H; Beauchaine, Theodore P; Thayer, Julian F; Kaess, Michael

    2016-06-01

    Among adults, depression is associated with reduced vagal activity, as indexed by high frequency heart rate variability [HF-HRV]), which correlates inversely with depression severity. Available evidence in depressed children and adolescents remains to be reviewed systematically. A search of the literature was performed to identify studies reporting (i) HF-HRV in clinically depressed children/adolescents relative to controls (k=4, n=259) and (ii) the association between HF-HRV and depressive symptoms as measured by standardized psychometric instruments in children and adolescents (k=6, n=2625). Random-effects meta-analysis on group differences revealed significant effects that were associated with a moderate effect size (Hedges' g=-0.59; 95% CI [-1.05; -0.13]), indicating lower resting state HF-HRV among clinically depressed children/adolescents (n=99) compared to healthy controls (n=160), consistent with findings among adults. While no correlation between HF-HRV and depressive symptom severity was observed (r=-.041 [-0.143; 0.062]), these additional correlational findings are limited to non-clinical samples. Findings have important clinical implications including a potentially increased risk for future physical ill health and also the identification of potential new treatment targets in child and adolescent depression.

  9. Dimensional approach to symptom factors of major depressive disorder in Koreans, using the Brief Psychiatric Rating Scale: the Clinical Research Center for Depression of South Korea study.

    PubMed

    Park, Seon-Cheol; Jang, Eun Young; Kim, Daeho; Jun, Tae-Youn; Lee, Min-Soo; Kim, Jae-Min; Kim, Jung-Bum; Jo, Sun-Jin; Park, Yong Chon

    2015-01-01

    Although major depressive disorder (MDD) has a variety of symptoms beyond the affective dimensions, the factor structure and contents of comprehensive psychiatric symptoms of this disorder have rarely been explored using the 18-item Brief Psychiatric Rating Scale (BPRS). We aimed to identify the factor structure of the 18-item BPRS in Korean MDD patients. A total of 258 MDD patients were recruited from a multicenter sample of the Clinical Research Center for Depression of South Korea study. Psychometric scales were used to assess overall psychiatric symptoms (BPRS), depression (Hamilton Depression Rating Scale), anxiety (Hamilton Anxiety Rating Scale), global severity (Clinical Global Impression of Severity Scale), suicidal ideation (Scale for Suicide Ideation), functioning (Social and Occupational Functioning Assessment Scale), and quality of life (World Health Organization Quality of Life Assessment-abbreviated version). Common factor analysis with oblique rotation was used to yield factor structure. A four-factor structure was designed and interpreted by the symptom dimensions to reflect mood disturbance, positive symptoms/apathy, bipolarity, and thought distortion/mannerism. These individual factors were also significantly correlated with clinical variables. The findings of this study support the view that the BPRS may be a promising measuring tool for the initial assessment of MDD patients. In addition, the four-factor structure of the BPRS may be useful in understanding the mood and psychotic characteristics of these patients.

  10. High-Precision 40Ar/39Ar Geochronology and Geology of St. George Island, Pribilof Islands, Alaska: Implications for Eruption Rates in the Bering Sea Basalt Province

    NASA Astrophysics Data System (ADS)

    Feeley, T. C.; Cosca, M. A.; Hamblock, J. M.; Underwood, S. J.

    2007-12-01

    New high-precision 40Ar/39Ar ages and geologic mapping establish an eruptive chronology for St. George Island, Pribilof Islands, Alaska. St. George is part of the Bering Sea basalt province (BSBP), a group of 15 late Cenozoic (mostly < 6 Ma) alkalic to tholeiitic basaltic volcanic fields widely distributed on islands in the Bering Sea, along the west coast of Alaska, and along the coast of northeast Russia. Twelve samples of washed, but otherwise untreated, whole-rock basalts from St. George were cut with a micro-wire saw into chips ~3 mm3 in size and irradiated for 40Ar/39Ar analysis. The chips were incrementally heated with a CO2 laser equipped with an integrator lens, and analyzed using a NU Instruments Noblesse mass spectrometer equipped with a Faraday cup and two ion counting electron multipliers. Detector intercalibration was done using automated air pipettes. A minimum of 20 heating steps were measured per sample, with the data often defining age plateaux. Isochron plots of the data yield ages ranging from 1.57 ± 0.04 to 2.89 ± 0.11 Ma, with trapped 40Ar/36Ar ratios ranging from 312 to 330. The stratigraphic positions of the dated rocks are known directly from field relations and there are no discrepancies between the 40Ar/39Ar ages and this sequence. Geochemical data combined with the age data indicate no progressive petrologic trends during evolution of the magmatic system, except for intermittent eruption of distinctive plagioclase-phyric basalts with low to moderate MgO contents (7 - 5 wt%) beginning at ~2.0 Ma. The new age data combined with volume estimates indicate an average subaerial eruption rate of ~107 m3km-2yr-1, which is adjusted for 3% sedimentary and ultramafic basement rocks beneath the volcanic pile, an average vesicularity of 5%, and an assumed surficial erosion value of 20%. This rate is identical to the estimate (110 m3km-2yr-1) by Mukasa et al. (JGR 112, 2007) for St. George Island. Both estimates, however, do not account for

  11. Urdu translation of the Hamilton Rating Scale for Depression: Results of a validation study

    PubMed Central

    Hashmi, Ali M.; Naz, Shahana; Asif, Aftab; Khawaja, Imran S.

    2016-01-01

    Objective: To develop a standardized validated version of the Hamilton Rating Scale for Depression (HAM-D) in Urdu. Methods: After translation of the HAM-D into the Urdu language following standard guidelines, the final Urdu version (HAM-D-U) was administered to 160 depressed outpatients. Inter-item correlation was assessed by calculating Cronbach alpha. Correlation between HAM-D-U scores at baseline and after a 2-week interval was evaluated for test-retest reliability. Moreover, scores of two clinicians on HAM-D-U were compared for inter-rater reliability. For establishing concurrent validity, scores of HAM-D-U and BDI-U were compared by using Spearman correlation coefficient. The study was conducted at Mayo Hospital, Lahore, from May to December 2014. Results: The Cronbach alpha for HAM-D-U was 0.71. Composite scores for HAM-D-U at baseline and after a 2-week interval were also highly correlated with each other (Spearman correlation coefficient 0.83, p-value < 0.01) indicating good test-retest reliability. Composite scores for HAM-D-U and BDI-U were positively correlated with each other (Spearman correlation coefficient 0.85, p < 0.01) indicating good concurrent validity. Scores of two clinicians for HAM-D-U were also positively correlated (Spearman correlation coefficient 0.82, p-value < 0.01) indicated good inter-rater reliability. Conclusion: The HAM-D-U is a valid and reliable instrument for the assessment of Depression. It shows good inter-rater and test-retest reliability. The HAM-D-U can be a tool either for clinical management or research. PMID:28083049

  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. Dissociation, cognitive conflict and nonlinear patterns of heart rate dynamics in patients with unipolar depression.

    PubMed

    Bob, Petr; Susta, Marek; Gregusova, Alica; Jasova, Denisa

    2009-02-01

    Recent findings in cognitive neuroscience indicate that activation of anterior cingulate cortex (ACC) is related to detecting cognitive conflict. Conflict related ACC activation elicits responses in central autonomic network which can be assessed by psychophysiological measures such as heart rate variability (i.e. beat to beat R-R intervals--RRI). Recent findings in neuroscience also suggest that cognitive conflict is related to specific nonlinear chaotic changes of the signal generated by the neural systems. The present study used Stroop word-colour test as an experimental approach to the study of cognitive conflict in connection with RRI measurement, psychometric measurement of dissociation (DES) and calculation of largest Lyapunov exponents in nonlinear data analysis of RRI time series in 40 patients with unipolar depression and 35 healthy controls. Significant correlation 0.58 (p<0.01) between largest Lyapunov exponents and DES found in depressive patients indicate that cognitive conflict related neural interference during conflicting Stroop task is closely related to dissociative processes. These results present first supportive evidence that degree of chaos could be related to dissociation.

  14. 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.

  15. Is the link between depressed mood and heart rate variability explained by disinhibited eating and diet?

    PubMed

    Young, Hayley A; Cousins, Alecia L; Watkins, Heather T; Benton, David

    2017-02-01

    Consistently it has been reported that a depressed mood and low heart rate variability (HRV) are linked. However, studies have not considered that the association might be explained by dietary behaviour. The resting inter-beat interval data of 266 adults (Study 1: 156 (51M), Study 2: 112 (38M)) were recorded for six minutes and quantified using linear (HF power: 0.15-0.4Hz) and nonlinear indices (Sample entropy). Participants also completed the Profile of Mood States and the Three Factor Eating questionnaires. The Alternative Healthy Eating Index was used to quantify diet quality. In study 1 mood was associated with HRV; an effect partially mediated by diet. Study 2 replicated the finding: disinhibited eating (the tendency to lose control over one's eating) and diet sequentially mediated the association between mood and HRV. Diet plays a role in the link between mood and HRV and studies should consider the influence of this factor.

  16. Does screening HIV-positive individuals in Uganda for major depressive disorder improve case detection rates and antidepressant prescription?

    PubMed

    Akena, Dickens; Stein, Dan J; Joska, John

    2013-10-01

    Major depressive disorder in HIV-positive persons is often not diagnosed, and poorly treated. The effect of depression screening on case detection, and rates of antidepressant prescription is unknown.We assessed 368 participants for major depressive disorder, and provided clinicians with the results. Four weeks later, we abstracted information from the charts of the depressed patients to ascertain if they received antidepressants. We also randomly sampled the charts of 368 non-screened patients, to ascertain whether clinicians had diagnosed and prescribed antidepressant treatment.Major depressive disorder was identified in 17.9 % of the screened group, and in 2.1 % of the non-screened group [OR = 9.65, CI = (4.54-20.50)]. The screened individuals were 7.8 times more likely to receive antidepressants (95 % CI = 3.04-20.24). Identification of major depressive disorder by clinicians in HIV settings remains poor. However, routine screening can improve case detection rates and the proportion of patients receiving antidepressants.

  17. Rate and correlates of depression among elderly people attending primary health care centres in Al-Dakhiliyah governorate, Oman.

    PubMed

    Al-Sabahi, S M; Al Sinawi, H N; Al-Hinai, S S; Youssef, R M

    2014-04-03

    This study determined the rates and correlates of depression among community-dwelling elderly people, based on data from the comprehensive health assessment conducted in Al-Dakhiliyah governorate in Oman in 2008-2010. Data covered sociodemographic characteristics, medical and nutrition status, functional abilities, depression and dementia. The rate of depression was 16.9%, higher among women than men (19.3% versus 14.3%). Depression was independently predicted by the presence of social risk (OR = 3.44), dementia (OR = 3.17), impairment in activities of daily living (OR = 2.19), joint problems (OR = 1.52) and mobility restriction (OR = 1.43). If dementia was excluded from the model, depression was additionally predicted by poor perception of health (OR = 2.09), impairment in instrumental activities of daily living (OR = 1.47) and older ages of 70-< 80 years (OR = 1.63) and ≥ 80 years (OR = 1.75). Although not presenting as a complaint, depression in not uncommon among elderly people.

  18. Body downsizing caused by non-consumptive social stress severely depresses population growth rate.

    PubMed

    Edeline, Eric; Haugen, Thrond O; Weltzien, Finn-Arne; Claessen, David; Winfield, Ian J; Stenseth, Nils Chr; Vøllestad, L Asbjørn

    2010-03-22

    Chronic social stress diverts energy away from growth, reproduction and immunity, and is thus a potential driver of population dynamics. However, the effects of social stress on demographic density dependence remain largely overlooked in ecological theory. Here we combine behavioural experiments, physiology and population modelling to show in a top predator (pike Esox lucius) that social stress alone may be a primary driver of demographic density dependence. Doubling pike density in experimental ponds under controlled prey availability did not significantly change prey intake by pike (i.e. did not significantly change interference or exploitative competition), but induced a neuroendocrine stress response reflecting a size-dependent dominance hierarchy, depressed pike energetic status and lowered pike body growth rate by 23 per cent. Assuming fixed size-dependent survival and fecundity functions parameterized for the Windermere (UK) pike population, stress-induced smaller body size shifts age-specific survival rates and lowers age-specific fecundity, which in Leslie matrices projects into reduced population rate of increase (lambda) by 37-56%. Our models also predict that social stress flattens elasticity profiles of lambda to age-specific survival and fecundity, thus making population persistence more dependent on old individuals. Our results suggest that accounting for non-consumptive social stress from competitors and predators is necessary to accurately understand, predict and manage food-web dynamics.

  19. Body downsizing caused by non-consumptive social stress severely depresses population growth rate

    PubMed Central

    Edeline, Eric; Haugen, Thrond O.; Weltzien, Finn-Arne; Claessen, David; Winfield, Ian J.; Stenseth, Nils Chr.; Vøllestad, L. Asbjørn

    2010-01-01

    Chronic social stress diverts energy away from growth, reproduction and immunity, and is thus a potential driver of population dynamics. However, the effects of social stress on demographic density dependence remain largely overlooked in ecological theory. Here we combine behavioural experiments, physiology and population modelling to show in a top predator (pike Esox lucius) that social stress alone may be a primary driver of demographic density dependence. Doubling pike density in experimental ponds under controlled prey availability did not significantly change prey intake by pike (i.e. did not significantly change interference or exploitative competition), but induced a neuroendocrine stress response reflecting a size-dependent dominance hierarchy, depressed pike energetic status and lowered pike body growth rate by 23 per cent. Assuming fixed size-dependent survival and fecundity functions parameterized for the Windermere (UK) pike population, stress-induced smaller body size shifts age-specific survival rates and lowers age-specific fecundity, which in Leslie matrices projects into reduced population rate of increase (λ) by 37–56%. Our models also predict that social stress flattens elasticity profiles of λ to age-specific survival and fecundity, thus making population persistence more dependent on old individuals. Our results suggest that accounting for non-consumptive social stress from competitors and predators is necessary to accurately understand, predict and manage food-web dynamics. PMID:19923130

  20. Variable SO2 emission rates for Anatahan volcano, the Commonwealth of the Northern Mariana Islands: Implications for deriving arc-wide volatile fluxes from erupting volcanoes

    NASA Astrophysics Data System (ADS)

    Hilton, D. R.; Fischer, T. P.; McGonigle, A. J. S.; de Moor, J. M.

    2007-07-01

    We report new spectroscopic-derived SO2 emission rates for Anatahan volcano, Mariana Islands. Measurements of SO2 fluxes reveal large fluctuations over the 2003-2005 period - from 78 kg s-1 which occurred on the same day as resurgent volcanic activity (March, 2005) to 50 kg s-1 and 25 kg s-1 made days/weeks after the start of eruptive sequences in 2003 and 2004 respectively. Even the lowest values make Anatahan a major global source of SO2 over the past decade. These SO2 emission rates are used to estimate the CO2 flux from the arc as a whole (=3.6 - 40 × 107 mol km-1 yr-1). Such values are significantly higher than estimates derived using other approaches: they are also high compared to other convergent margins (e.g., Central America) where the input flux of CO2 is substantially greater. Our results caution against including volatile fluxes from actively-degassing volcanoes to produce volatile outputs considered representative of entire arc fronts.

  1. Heart rate variability (HRV) in adolescent females with anxiety disorders and major depressive disorder

    PubMed Central

    Henje Blom, E; Olsson, EM; Serlachius, E; Ericson, M; Ingvar, M

    2010-01-01

    Aim: The aim of this study was to investigate heart rate variability (HRV) in a clinical sample of female adolescents with anxiety disorders (AD) and/or major depressive disorder (MDD) compared with healthy controls and to assess the effect of selective serotonin reuptake inhibitors (SSRI) on HRV. Methods: Heart rate variability was measured in adolescent female psychiatric patients with AD and/or MDD (n = 69), mean age 16.8 years (range: 14.5–18.4), from 13 out-patient clinics and in healthy controls (n = 65), mean age 16.5 years (range: 15.9–17.7). HRV was registered in the sitting position during 4 min with no interventions. Results: Logarithmically transformed high frequency HRV (HF), low frequency HRV (LF) and standard deviation of inter beat intervals (SDNN) were lower in the clinical sample compared with the controls (Cohen’s d for HF = 0.57, LF = 0.55, SDNN = 0.60). This was not explained by body mass index, blood pressure or physical activity. Medication with SSRI explained 15.5% of the total variance of HF, 3.0% of LF and 6.5% of SDNN. Conclusions: Adolescent female psychiatric patients with AD and/or MDD show reduced HRV compared with healthy controls. Medication with SSRI explained a part of this difference. PMID:20121706

  2. Spatial and temporal variations of soil CO2 degassing rate at El Hierro volcanic system and relation to the 2011 submarine eruption

    NASA Astrophysics Data System (ADS)

    Melían, G.; Barrancos, J.; Padilla, G.; Dionis, S.; Rodríguez, F.; Nolasco, D.; Padrón, E.; Hernández, P. A.; Calvo, D.; Hernández, I.; Peréz, N. M.; Peraza, M. D.

    2012-04-01

    El Hierro Island (278 km2) is the youngest and the SW-most of the Canary Islands. On July 16, 2011, a seismic-volcanic crisis started with the occurrence of more than 11,900 seismic events. On October 10, 2011, the seismic activity changed behaviour and produced a harmonic tremor due to magma movement suggesting the initial stage of an eruption. The purpose of this study is to investigate the spatial and temporal variations of soil CO2 degassing rates at El Hierro volcanic system and its relation with the 2011 El Hierro volcanic unrest. Since 1998, diffuse CO2 emission has been investigated at El Hierro volcanic system in a yearly basis during the summer periods with approximately 600 observation sites. From 2004 to 2009, a diffuse CO2 emission rate decreasing trend from 1434 to 358 t•d-1 (equivalent to background values) was observed, and this tendency changed from 2009 to 2010 reaching a diffuse CO2 emission rate of 970 t•d-1. Because of this observed tendency change on the diffuse CO2 emission rate is possible to think that the preliminary stages of the 2011 volcanic unrest at El Hierro did start by the middle of 2010 with aseismic magma rising in the upper mantle beneath El Hierro. Since July 2011 and due to the start of the seismic-volcanic crisis at El Hierro, 16 diffuse CO2 emission surveys have been undertaken until January 2012. Diffuse CO2 emission measurements were performed by means of portable NDIR sensors according to the accumulation chamber method. Observed soil CO2 efflux values for all the 2011-12 surveys have ranged from negligible values to 398 g•m-2•d-1. The diffuse CO2 output released to atmosphere for the 2011-12 surveys was estimated between 138 and 2,143 t•d-1. On October 6, 2011, an increase tendency of diffuse CO2 emission rate from 380 to 990 t•d-1 was observed prior the occurrence of the first 4 magnitude type earthquake on October 8, 2011, and El Hierro submarine eruption on October 12, 2011. From October 15, 2011, an

  3. 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…

  4. Rasch Rating Scale Modeling of the Korean Version of the Beck Depression Inventory

    ERIC Educational Resources Information Center

    Hong, Sehee; Wong, Eunice C.

    2005-01-01

    The Beck Depression Inventory (BDI) is one of the most frequently used instruments in the study of depression both within and outside of the United States. Though developed primarily with European American clinical populations, the BDI has been applied in nonclinical and non-Western samples. To determine whether such a practice is warranted, the…

  5. Depressive Symptoms Among Heavy Cigarette Smokers: The Influence of Daily Rate, Gender, and Race

    PubMed Central

    2013-01-01

    Introduction: Cigarette smokers experience higher levels of depressive symptoms and are more likely to be diagnosed with depressive disorders than nonsmokers. To date, the nature of the smoking–depression relationship has not been adequately studied among heavy smokers, a group at elevated risk for poor health outcomes. In this study, we examined depressive symptom expression among heavy smokers while considering the moderating roles of smoking status, gender, and race. We also explored whether amount of tobacco usually consumed had an impact. Methods: We extracted data from a large, highly nicotine-dependent, nontreatment cigarette smoking study sample (N = 6,158). Participants who consented were screened for major exclusions, and they completed questionnaires. Results: Smokers reported a higher, clinically meaningful level of depressive symptoms relative to nonsmokers (27.3% of smokers vs. 12.5% of nonsmokers) scored above the clinical cutoff on the Center for Epidemiological Studies Depression (CES-D) scale (p < .001), which differed among race × gender subgroups. Further, amount of daily intake was inversely associated with self-report of depressive symptoms. For every 10-cigarette increment, the likelihood of scoring above the CES-D clinical cutoff decreased by 62% (p < .0001). Conclusions: These findings improve our understanding of tobacco’s influence on depressive symptom expression among heavy smokers, with implications for tailoring evidence-based tobacco treatments. PMID:23569006

  6. 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

  7. Depression during pregnancy: rates, risks and consequences--Motherisk Update 2008.

    PubMed

    Marcus, Sheila M

    2009-01-01

    Affective illness is common in women, and the puerperium is a time of particular vulnerability. Gender differences in the expression of affective disorders have been attributed to the impact of hormonal influence, socialization, and genetics. Dramatic fluctuations in gonadal hormones that occur following childbirth, influences the increased incidence of mood disorders during this time. Numerous tools including the Edinburgh Postpartum Depression Scale can be used to screen for depression during pregnancy and postpartum. While screening tools may assist with appropriately identifying women who should be further assessed, their use alone does not significantly increase treatment seeking in women, even when their providers are notified about risk. Many studies demonstrate that only a small number (18%) of women who meet criteria for major depressive disorder seek treatment during pregnancy and postpartum. Additionally, common symptoms of depression (sleep, energy and appetite change) may be misinterpreted as normative experiences of pregnancy.Treatment engagement is important as untreated depression during pregnancy may have unfavorable outcomes for both women and children. Complications of pregnancy associated with depression include: inadequate weight gain,under utilization of prenatal care, increased substance use, and premature birth. Human studies demonstrate that perceived life-event stress, as well as depression and anxiety predicted lower birth weight, decreased Apgar scores, and smaller head circumference, and small for gestational age babies. Postpartum depression (PPD) is a common clinical disorder occurring in 15% of deliveries,making it one of the most frequent conditions to complicate pregnancy. Risk factors include past personal or family history of depression, sing marital status, poor health functioning, lower SES, and alcohol use. Women who have a prior history of postpartum depression, particularly with features of bipolarity or psychosis may be at

  8. Refugee, asylum seeker, immigrant women and postnatal depression: rates and risk factors.

    PubMed

    Collins, Catherine H; Zimmerman, Cathy; Howard, Louise M

    2011-02-01

    Postnatal depression (PND) is recognised as a common maternal health problem, but little evidence examines PND among refugee, asylum seeker and immigrant women in developed country settings. This review aimed to identify the rates of PND and highlight common risk factors among this group of women. An iterative and dynamic literature search was conducted across ten databases to identify published articles on PND among immigrant, asylum-seeking and refugee women in developed country settings. Medical Subject Headings (MeSH) and 'free text' search terms, as well as thesaurus terms, acronyms and truncation were used where appropriate. Findings suggest that PND may affect up to 42% of migrant women, compared to around 10-15% of native-born women. Common risk factors for PND among migrant women include history of stressful life events, lack of social support and cultural factors. With a growing number of babies born to immigrant mothers, greater awareness of PND among this group is needed in order to respond to their particular maternal mental health needs. Maternity care providers should regard all recent immigrants as at high risk of PND and give closer observation and support as necessary.

  9. 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.

  10. 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.

  11. 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.

  12. 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

    2016-01-04

    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.

  13. 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.

  14. 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..

  15. Population prevalence of edentulism and its association with depression and self-rated health.

    PubMed

    Tyrovolas, Stefanos; Koyanagi, Ai; Panagiotakos, Demosthenes B; Haro, Josep Maria; Kassebaum, Nicholas J; Chrepa, Vanessa; Kotsakis, Georgios A

    2016-11-17

    Edentulism is associated with various adverse health outcomes but treatment options in low- and middle-income countries (LMICs) are limited. Data on its prevalence and its effect on mental health and overall-health is lacking, especially from LMICs. Self-reported data on complete edentulism obtained by standardized questionnaires on 201,953 adults aged ≥18 years from 50 countries which participated in the World Health Survey (WHS) 2002-2004 were analyzed. Age and sex-standarized edentulism prevalence ranged from 0.1% (95% CI = 0.0-0.3) (Myanmar) to 14.5% (95% CI = 13.1-15.9) (Zimbabwe), and 2.1% (95% CI = 1.5-3.0) (Ghana) to 32.3% (95% CI = 29.0-35.8) (Brazil) in the younger and older age groups respectively. Edentulism was significantly associated with depression (OR 1.57, 95% CI = 1.23-2.00) and poor self-rated health (OR 1.38, 95% CI = 1.03-1.83) in the younger group with no significant associations in the older age group. Our findings highlight the edentulism-related health loss in younger persons from LMICs. The relative burden of edentulism is likely to grow as populations age and live longer. Given its life-long nature and common risk factors with other NCDs, edentulism surveillance and prevention should be an integral part of the global agenda of NCD control.

  16. Post-Traumatic Stress Disorder, Depression, and Heart-Rate Variability among North Korean Defectors

    PubMed Central

    Song, Byoung-A; Yoo, So-Young; Kang, Hee-Young; Byeon, Seong-Hye; Shin, Sang-Ho; Hwang, Eun-Jeong

    2011-01-01

    Objective This study evaluated the symptoms of post-traumatic stress disorder (PTSD) among North Korean defectors and their level of suicidal ideation and the correlation between these and heart-rate variability (HRV) to explore the possibility of using HRV as an objective neurobiological index of signs of autonomic nervous system disorder. Methods A total of 32 North Korean defectors (nine men, 23 women) were selected as subjects, and their HRV was measured after they completed the Minnesota Multiphasic Personality Inventory-PTSD (MMPI-PTSD) scale and the Beck Depression Inventory (BDI). Results 1) Low-frequency (LF)/high-frequency (HF) ratios in the HRV index and MMPI-PTSD scores were correlated (r=0.419, p<0.05), as were BDI item 9 (suicidal ideation) and MMPI-PTSD scores (r=0.600, p<0.01). 2) A regression analysis of LF/HF ratios and MMPI-PTSD scores revealed an R-value of 13.8% (Adj. R2=0.138, F=4.695, p=0.041), and a regression analysis of BDI item 9 and MMPI-PTSD scores showed an R-value of 32.8% (Adj. R2=0.328, F=11.234, p=0.003). In other words, the LF/HF ratio (β=0.419) and BDI item 9 (β=0.600) appear to be risk factors in predicting MMPI-PTSD scores. Conclusion The LF/HF ratio, a standard index of autonomic nervous system activity, can be used as an objective neurobiological index to analyze PTSD among North Korean defectors presenting with various mental and physical symptoms, and the approximate level of suicide -ideation can act as a predicting factor for PTSD. PMID:22216038

  17. Population prevalence of edentulism and its association with depression and self-rated health

    PubMed Central

    Tyrovolas, Stefanos; Koyanagi, Ai; Panagiotakos, Demosthenes B.; Haro, Josep Maria; Kassebaum, Nicholas J.; Chrepa, Vanessa; Kotsakis, Georgios A.

    2016-01-01

    Edentulism is associated with various adverse health outcomes but treatment options in low- and middle-income countries (LMICs) are limited. Data on its prevalence and its effect on mental health and overall-health is lacking, especially from LMICs. Self-reported data on complete edentulism obtained by standardized questionnaires on 201,953 adults aged ≥18 years from 50 countries which participated in the World Health Survey (WHS) 2002–2004 were analyzed. Age and sex-standarized edentulism prevalence ranged from 0.1% (95% CI = 0.0–0.3) (Myanmar) to 14.5% (95% CI = 13.1–15.9) (Zimbabwe), and 2.1% (95% CI = 1.5–3.0) (Ghana) to 32.3% (95% CI = 29.0–35.8) (Brazil) in the younger and older age groups respectively. Edentulism was significantly associated with depression (OR 1.57, 95% CI = 1.23–2.00) and poor self-rated health (OR 1.38, 95% CI = 1.03–1.83) in the younger group with no significant associations in the older age group. Our findings highlight the edentulism-related health loss in younger persons from LMICs. The relative burden of edentulism is likely to grow as populations age and live longer. Given its life-long nature and common risk factors with other NCDs, edentulism surveillance and prevention should be an integral part of the global agenda of NCD control. PMID:27853193

  18. 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.

  19. ST/HR hysteresis: exercise and recovery phase ST depression/heart rate analysis of the exercise ECG.

    PubMed

    Lehtinen, R

    1999-01-01

    ST segment depression/heart rate (ST/HR) hysteresis is a recently introduced novel computer method for integrating the exercise and recovery phase ST/HR analysis for improved detection of coronary artery disease (CAD). It is a continuous diagnostic variable that extracts the prevailing direction and average magnitude of the hysteresis in ST depression against HR during the first 3 consecutive minutes of postexercise recovery. This article reviews the development and evaluation of this new method in a clinical population of 347 patients referred for a routine bicycle exercise electrocardiographic (ECG) test at Tampere University Hospital, Finland. Of these patients, 127 had angiographically proven CAD, whereas 13 had no CAD according to angiography, 18 had no perfusion defect according to Tc-99m-sestamibi myocardial imaging and single photon emission computed tomography, and 189 were clinically normal with respect to cardiac diseases. For each patient, the values for ST/HR hysteresis, ST/HR index, end-exercise ST depression, and recovery ST depression were determined for each lead of the Mason-Likar modification of the standard 12-lead exercise ECG and maximum value from the lead system (aVL, aVR, and V1 excluded). The area under the receiver operating characteristics curve (ie, the discriminative capacity) of the ST/HR hysteresis was 89%, which was significantly larger than that of the end-exercise ST depression (76%, P < .0001), recovery ST depression (84%, P = .0063) or ST/HR index (83%, P = .0023), indicating the best diagnostic performance of the ST/HR hysteresis in detection of CAD regardless of the partition value selection. Furthermore, the superior diagnostic performance of the method was relatively insensitive to the ST segment measurement point or to the ECG lead selection. These results suggest that the ST/HR hysteresis improves the clinical utility of the exercise ECG test in detection of CAD.

  20. 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

  1. The Effect of Deployment on the Rate of Major Depression and Substance Abuse in Active Duty Military from 2001-2006

    DTIC Science & Technology

    2011-03-01

    Major Depression , Rates of Substance Abuse, Deployment Effects, OEF, OIF, Comorbidity, Mental Health Illness 16. PRICE CODE 17. SECURITY...health illness . This thesis evaluates the effects of deployment history on major depression and substance abuse in the active duty population from...trend in mental health illness , depression , and substance abuse being the top two diagnoses. Mental health illness affects readiness, and the cost of

  2. 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.

  3. The influence of stress, depression, and anxiety on PSA screening rates in a nationally-representative sample

    PubMed Central

    Kotwal, Ashwin A.; Schumm, Phil; Mohile, Supriya G.; Dale, William

    2012-01-01

    Background Prostate-specific antigen (PSA) testing for prostate cancer (PCa) is controversial, with concerning rates of both over- and under-screening. The reasons for the observed rates of screening are unknown, and few studies have examined the relationship of psychological health to PSA screening rates. Understanding this relationship can help guide interventions to improve informed-decision making (IDM) for screening. Methods A nationally-representative sample of men 57–85 years old without PCa (N=1,169) from the National Social life, Health and Aging Project (NSHAP) was analyzed. The independent relationship of validated psychological health scales measuring stress, anxiety, and depression to PSA testing rates was assessed using multvariable logistic regression analyses. Results PSA screening rates were significantly lower for men with higher perceived stress (OR=0.76, p=0.006), but not for higher depressive symptoms (OR=0.89, p=0.22) when accounting for stress. Anxiety influences PSA screening through an interaction with number of doctor visits (p=0.02). Among the men who visited the doctor 1 time, those with higher anxiety were less likely to be screened (OR=0.65, p=0.04). Conversely, among those who visited the doctor 10+ times with higher anxiety were more likely to be screened (OR=1.71, p=0.04). Conclusions Perceived stress significantly lowers PSA screening likelihood, and it appears to partly mediate the negative relationship of depression with screening likelihood. Anxiety affects PSA screening rates differently for men with different numbers of doctor visits. Interventions to influence PSA screening rates should recognize the role of the patients’ psychological state to improve their likelihood of making informed decisions and improve screening appropriateness. PMID:22955835

  4. 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?

  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. 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.

  7. 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…

  8. Associations between Physical Activity and Reduced Rates of Hopelessness, Depression, and Suicidal Behavior among College Students

    ERIC Educational Resources Information Center

    Taliaferro, Lindsay A.; Rienzo, Barbara A.; Pigg, R. Morgan; Miller, M. David; Dodd, Virginia J.

    2009-01-01

    Objective: The authors explored associations among types of physical activity and hopelessness, depression, and suicidal behavior among college students. Participants: Participants included 43,499 college students aged 18 to 25 who completed the 2005 National College Health Assessment conducted by the American College Health Association. Methods:…

  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. Pre-, Syn- and Post Eruptive Seismicity of the 2011 Eruption of Nabro Volcano, Eritrea

    NASA Astrophysics Data System (ADS)

    Goitom, Berhe; Hammond, James; Kendall, Michael; Nowacky, Andy; Keir, Derek; Oppenheimer, Clive; Ogubazghi, Ghebrebrhan; Ayele, Atalay; Ibrahim, Said; Jacques, Eric

    2014-05-01

    Nabro volcano, located in south-east Eritrea, East Africa, lies at the eastern margin of the Afar Rift and the Danakil Depression. Its tectonic behaviour is controlled by the divergence of the Arabian, Nubian and Somali plates. Nabro volcano was thought to be seismically quiet until it erupted in June 2011 with limited warning. The volcano erupted on June 12, 2011 around 20:32 UTC, following a series of earthquakes on that day that reached a maximum magnitude of 5.8. It is the first recorded eruption of Nabro volcano and only the second in Eritrea, following the Dubbi eruption in 1861. A lava flow emerged from the caldera and travelled about 20 km from the vent and buried settlements in the area. At the time of this eruption there was no seismic network in Eritrea, and hence the volcano was not monitored. In this study we use ten Ethiopian, one Yemeni and one Djibouti stations to investigate the seismicity of the area before, during and after the eruption. Four Eritrean seismic stations deployed in June 2011, four days after the eruption, are also included in the dataset. Travel time picks supplied by colleagues from Djibouti were also incorporated into the dataset. Our analysis covers roughly three months before and after the eruption and shows that Nabro was seismically quiet before the eruption (nine events), with the exception of one major earthquake (4.8 magnitude) that occurred on March 31, 2011. In contrast, the region shows continued seismic activity after the eruption (92 events). During the eruption seismicity levels are high (123 events), with two days particularly active, June 12 and June 17 with 85 and 28 discrete events, respectively. Maximum magnitudes of 5.8 and 5.9 were recorded on these two days. The two days of increased seismicity are consistent with satellite observations of the eruption which show two distinct phases of the eruption. The period between these two phases was dominated by volcanic tremor. The tremor signal lasted for almost one

  11. The 1991 eruption of Hekla, Iceland

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust; Oskarsson, Niels; Gronvold, Karl; Saemundsson, Kristjan; Sigurdsson, Oddur; Stefansson, Ragnar; Gislason, Sigurdur R.; Einarsson, Pall; Brandsdottir, Bryndis; Larsen, Gudrun; Johannesson, Haukur; Thordarson, Thorvaldur

    1992-02-01

    The eruption that started in the Hekla volcano in South Iceland on 17 January 1991, and came to an end on 11 March, produced mainly andesitic lava. This lava covers 23 km2 and has an estimated volume of 0.15 km3. This is the third eruption in only 20 years, whereas the average repose period since 1104 is 55 years. Earthquakes, as well as a strain pulse recorded by borehole strainmeters, occurred less than half an hour before the start of the eruption. The initial plinian phase was very short-lived, producing a total of only 0.02 km3 of tephra. The eruption cloud attained 11.5 km in height in only 10 min, but it became detached from the volcano a few hours later. Several fissures were active during the first day of the eruption, including a part of the summit fissure. By the second day, however, the activity was already essentially limited to that segment of the principal fissure where the main crater subsequently formed. The average effusion rate during the first two days of the eruption was about 800 m3 s-1. After this peak, the effusion rate declined rapidly to 10 20 m3 s-1, then more slowly to 1 m3 s-1, and remained at 1 12 m3 s-1 until the end of the eruption. Site observations near the main crater suggest that the intensity of the volcanic tremor varied directly with the force of the eruption. A notable rise in the fluorine concentration of riverwater in the vicinity of the eruptive fissures occurred on the 5th day of the eruption, but it levelled off on the 6th day and then remained essentially constant. The volume and initial silica content of the lava and tephra, the explosivity and effusion rate during the earliest stage of the eruption, as well as the magnitude attained by the associated earthquakes, support earlier suggestions that these parameters are positively related to the length of the preceeding repose period. The chemical difference between the eruptive material of Hekla itself and the lavas erupted in its vicinity can be explained in terms of a

  12. The 1631 eruption of Vesuvius

    NASA Astrophysics Data System (ADS)

    Rolandi, G.; Barrella, A. M.; Borrelli, A.

    1993-11-01

    Contemporary accounts of the violent eruption of Vesuvius in 1631 are reviewed, and recorded events are correlated with resulting volcanic deposits. Field study of the deposits in the proximal area revealed the presence of tephra falls, pyroclastic flows and lava, with subordinate surge deposits. A total volume of 1.1 km 3 (0.55 km 3 DRE) of phono-tephritic to phonolitic magma was ejected during 24 hours. The different magma compositions correspond with a transition from a lower, white, aphyric, highly vesiculated pumice (layer 1) to an upper, gray, crystal-rich, poorly vesiculated pumice (layer 3), showing reverse grading. Isopach and isopleth maps of the tephra-falls have been constructed to determine changes in the eruptive style and temporal evolution of the eruption column which reached a maximum height of 16 to 28 km. The recorded column height variations show a change in the mass discharge rate (8.9 × 10 6 kg/s to 8.2 × 10 7 kg/s) and the occurrence of pyroclastic flows during the deposition of the weakly vesiculated, dense pumice of the upper part of layer 3. Pyroclastic flows are crystal-rich and show St. Vincent-type features. The explosive phase demolished the upper part of the pre-existing cone, and debris flows invaded the southern side of the volcano. In the afternoon of December 17, 1631 an outbreak of lava flow from a southern lateral fracture system occurred, and effusion of lava continued up to midnight of December 18. Intermittent steam blasts continued to the end of December, when the eruption ended and Mount Vesuvius entered a solfataric phase. The earthquakes that had marked both the pre-eruptive and eruptive phases, continued, however, well into March 1632.

  13. 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

  14. The effect of inbreeding rate on fitness, inbreeding depression and heterosis over a range of inbreeding coefficients

    PubMed Central

    Pekkala, Nina; Knott, K Emily; Kotiaho, Janne S; Nissinen, Kari; Puurtinen, Mikael

    2014-01-01

    Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within-population inbreeding depression (reduction in fitness of offspring from inbred versus random mating within a population) and (iii) heterosis (increase in fitness of offspring from interpopulation versus within-population random mating). Inbreeding rate was manipulated by using three population sizes (2, 10 and 40), and fitness was measured as offspring survival and fecundity. Fast inbreeding (smaller effective population size) resulted in greater reduction in population mean fitness than slow inbreeding, when populations were compared over similar inbreeding coefficients. Correspondingly, populations with faster inbreeding expressed more heterosis upon interpopulation hybridization. Inbreeding depression within the populations did not have a clear relationship with either the rate or the level of inbreeding. PMID:25553071

  15. Exercise interventions for smokers with a history of alcoholism: exercise adherence rates and effect of depression on adherence.

    PubMed

    Patten, Christi A; Vickers, Kristin S; Martin, John E; Williams, Carl D

    2003-06-01

    This study examined the adherence rates and the effect of depression on adherence in two studies conducted among smokers with a past history of alcoholism. In both studies, subjects participated in a 12-session group-based exercise intervention for smoking cessation. The target quit date (TQD) was Session 8. Participants in Study 1 were 73 smokers (43% female). Exercise instructions began at Session 8 and continued through Session 12. Mean frequency and number of minutes of exercise decreased during the 4 weeks of exercise treatment (P<.001). Study 2, conducted with 18 smokers (50% female), examined the feasibility of commencing exercise at Session 1, well before the TQD. The mean number of minutes exercised increased from Sessions 1 to 12 (P=.013). In both studies, average session attendance was high (82%). Combining subjects from both studies, depressed smokers at baseline reported greater mean frequency of exercise per week than nondepressed smokers (P=.05). The results suggest that depressed smokers can be engaged in an exercise program. Further research is needed to determine if commencing exercise early during treatment, prior to the TQD, improves adherence.

  16. Depression (Major Depressive Disorder)

    MedlinePlus

    ... related. Depression can cause pain — and pain can cause depression. Sometimes pain and depression create a vicious cycle ... depression worsens feelings of pain. In many people, depression causes unexplained physical symptoms such as back pain or ...

  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. Phreatomagmatic and water-influenced Strombolian eruptions of a small-volume parasitic cone complex on the southern ringplain of Mt. Ruapehu, New Zealand: Facies architecture and eruption mechanisms of the Ohakune Volcanic Complex controlled by an unstable fissure eruption

    NASA Astrophysics Data System (ADS)

    Kósik, S.; Németh, K.; Kereszturi, G.; Procter, J. N.; Zellmer, G. F.; Geshi, N.

    2016-11-01

    The Ohakune Volcanic Complex is a late Pleistocene tuff ring - scoria/spatter cone complex located south of Ruapehu volcano. This small-volume volcano consists of an outer E-W elongated compound tuff ring edifice, three inner scoria-spatter cones and further volcanic depressions, located on the Ohakune Fault. We quantified accurately the variations of the eruptive styles and processes through time by systematic sampling of key stratigraphic marker beds at proximal and distal locations, and the determination of grain size distribution, componentry, density and vesicularity. Using a Digital Terrain Model coupled with stratigraphic data, we also determined the spatial distribution and volume of each identified unit and individual edifices within the Ohakune Volcanic Complex. Activity began with a shallow phreatomagmatic phase characterized by an almost continuous generation of a low eruptive column, accompanied by wet pyroclastic density currents, together with the ejection of juvenile fragments and accidental lithics from the surrounding country rocks. Subsequent activity was dominated by a variety of Strombolian eruptions exhibiting differing intensities that were at times disrupted by phreatic blasts or phreatomagmatic explosions due to the interaction with external water and/or sudden changes in magma discharge rate. At least three major vent-shifting events occurred during the eruption, which is demonstrated by the truncation of the initial tuff ring and the infilling of the truncated area by several coarse grained surge units. Our study indicates that approx. 12 × 106 m3 DRE magma erupted within maximum 2.5 to 5 months through multiple vents. The erupted magma ascended from a depth of 16-18 km, and reached the surface within approximately 50 h. Alternating eruption styles, frequent vent-shifting and a variety of emplacement mechanisms inferred from the deposits of the Ohakune Volcanic Complex demonstrate the unpredictable nature of small-volume volcanism

  19. 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.

  20. 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.

  1. Major depression

    MedlinePlus

    Depression - major; Depression - clinical; Clinical depression; Unipolar depression; Major depressive disorder ... providers do not know the exact causes of depression. It is believed that chemical changes in the ...

  2. Does refining the phenotype improve replication rates? A review and replication of candidate gene studies on Major Depressive Disorder and Chronic Major Depressive Disorder.

    PubMed

    Luo, Xiaochen; Stavrakakis, Nikolaos; Penninx, Brenda W; Bosker, Fokko J; Nolen, Willem A; Boomsma, Dorret I; de Geus, Eco J; Smit, Johan H; Snieder, Harold; Nolte, Ilja M; Hartman, Catharina A

    2016-03-01

    Replication has been poor for previously reported candidate genes involved in Major Depressive Disorder (MDD). One possible reason is phenotypic and genetic heterogeneity. The present study replicated genetic associations with MDD as defined in DSM-IV and with a more narrowly defined MDD subtype with a chronic and severe course. We first conducted a systematic review of genetic association studies on MDD published between September 2007 and June 2012 to identify all reported candidate genes. Genetic associations were then tested for all identified single nucleotide polymorphisms (SNPs) and the entire genes using data from the GAIN genome-wide association study (MDD: n = 1,352; chronic MDD subsample: n = 225; controls: n =  1,649). The 1,000 Genomes database was used as reference for imputation. From 157 studies identified inthe literature, 81 studies reported significant associations with MDD, involving 245 polymorphisms in 97 candidate genes, from which we were able to investigate 185 SNPs in 89 genes. We replicated nine candidate SNPs in eight genes for MDD and six in five genes for chronic MDD. However, these were not more than expected by chance. At gene level, we replicated 18 genes for MDD and 17 genes for chronic MDD, both significantly more than expected by chance. We showed that replication rates were improved for MDD compared to a previous, highly similar, replication study based on studies published before 2007. Effect sizes of the SNPs and replication rates of the candidate genes were improved in the chronic subsample compared to the full sample. Nonetheless, replication rates were still poor.

  3. 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.

  4. An Experimental Investigation of Ice-melting and heat transfer rates from submerged warm water jets upward impinging into ice-blocks as analogous for water-filled cavities formed during subglacial eruptions.

    NASA Astrophysics Data System (ADS)

    Jamshidnia, Hamidreza; Gudmundsson, Magnus Tumi

    2016-11-01

    Rates of energy transfer in water-filled cavities formed under glaciers by geothermal and volcanic activity are investigated by conducting experiments in which hot water jets (10°- 90°C) impinging into an ice block for jet Reynolds numbers in turbulent regime of 10000 -70000. It is found that heat flux is linearly dependent on jet flow temperature. Water jet melts a cavity into an ice block. Cavities had steep to vertical sides with a doming roof. Some of ice blocks used had trapped air bubbles. In these cases that melting of the ice could have led to trapping of air at the top of cavity, partially insulating the roof from hot water jet. The overall heat transfer rate in cavity formation varied with jet temperature from <100 kW m-2 to 900 kW m-2 while melting rates in the vertical direction yield heat transfer rates of 200-1200 kW m-2. Experimental heat transfer rates can be compared to data on subglacial melting observed for ice cauldrons in Iceland. For lowest temperatures the numbers are comparable to those for geothermal water in cool, subglacial water bodies and above subglacial flowpaths of jökulhlaups. Highest experimental rates for 80-90°C jets are 3-10 times less than inferred from observations of recent subglacial eruptions (2000-4000 kW m-2) . This can indicate that single phase liquid water convection alone may not be sufficient to explain the rates seen in recent subglacial eruptions, suggesting that forced 2 or 3 phase convection can be common.

  5. Linear drug eruption.

    PubMed

    Alfonso, R; Belinchon, I

    2001-01-01

    Linear eruptions are sometimes associated with systemic diseases and they may also be induced by various drugs. Paradoxically, such acquired inflammatory skin diseases tend to follow the system of Blaschko's lines. We describe a case of unilateral linear drug eruption caused by ibuprofen, which later became bilateral and generalized.

  6. Generalized Eruptive Syringoma

    PubMed Central

    Avhad, Ganesh; Ghuge, Priyanka; Jerajani, HR

    2015-01-01

    Eruptive syringoma is a very rare variant of syringoma. It is a benign adnexal tumor of the intraepidermal portion of eccrine sweat ducts. Here we report a 32-year-old female presented with classical asymptomatic eruptive syringomas involving her face and extremities. PMID:25814740

  7. Mafic Plinian eruptions: Is fast ascent required?

    NASA Astrophysics Data System (ADS)

    Szramek, Lindsay Ann

    2016-10-01

    It has been hypothesized that for a Plinian eruption of mafic magma to occur, that magma must ascend rapidly from the chamber to cause it to fragment into a jet containing juvenile and nonjuvenile tephra. To determine how fast mafic Plinian magmas need to travel to the level of fragmentation, a number of decompression experiments were carried out on two hydrous mafic magmas, and the results are compared to the products of two well-documented mafic Plinian eruptions: the basaltic andesite Fontana eruption of Masaya (Nicaragua) and the hawaiite 122 B.C. eruption of Etna (Italy). Comparison of natural and experimental textures shows that the Fontana eruption can be replicated in the lab at decompression rates between 0.1 MPa s-1 and 0.2 MPa s-1. This decompression rate is faster than any previously determined experimentally rate for more silicic eruptions. The hawaiite was unable to be reproduced in the lab. The natural groundmass is highly crystalline, which would have raised the viscosity of the initial melt by 1-2 orders of magnitude, which may not be enough to cause fragmentation.

  8. Rates and predictors of postpartum depression by race and ethnicity: results from the 2004 to 2007 New York City PRAMS survey (Pregnancy Risk Assessment Monitoring System).

    PubMed

    Liu, Cindy H; Tronick, Ed

    2013-11-01

    The objective of this study was to examine racial/ethnic disparities in the diagnosis of postpartum depression (PPD) by: (1) identifying predictors that account for prevalence rate differences across groups, and (2) comparing the strength of predictors across groups. 3,732 White, African American, Hispanic, and Asian/Pacific Islander women from the New York City area completed the Pregnancy Risk Assessment Monitoring System from 2004 to 2007, a population-based survey that assessed sociodemographic risk factors, maternal stressors, psycho-education provided regarding depression, and prenatal and postpartum depression diagnoses. Sociodemographic and maternal stressors accounted for increased rates in PPD among Blacks and Hispanics compared to Whites, whereas Asian/Pacific Islander women were still 3.2 times more likely to receive a diagnosis after controlling for these variables. Asian/Pacific Islanders were more likely to receive a diagnosis after their providers talked to them about depressed mood, but were less likely than other groups to have had this conversation. Prenatal depression diagnoses increased the likelihood for PPD diagnoses for women across groups. Gestational diabetes decreased the likelihood for a PPD diagnosis for African Americans; a trend was observed in the association between having given birth to a female infant and increased rates of PPD diagnosis for Asian/Pacific Islanders and Whites. The risk factors that account for prevalence rate differences in postpartum diagnoses depend on the race/ethnic groups being compared. Prenatal depression is confirmed to be a major predictor for postpartum depression diagnosis for all groups studied; however, the associations between other postpartum depression risk factors and diagnosis vary by race/ethnic group.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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…

  15. 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.

  16. 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

  17. Presentation and validation of the multiple sclerosis depression rating scale: a test specifically devised to investigate affective disorders in multiple sclerosis patients.

    PubMed

    Quaranta, Davide; Marra, Camillo; Zinno, Massimiliano; Patanella, Agata Katia; Messina, Maria Josè; Piccininni, Chiara; Batocchi, Anna Paola; Gainotti, Guido

    2012-01-01

    Accurate diagnosis of depression in patients affected by MS is important, as it may be a cause of reduced quality of life and increased suicide risk. We present a new scale, the Multiple Sclerosis Depression Rating Scale (MSDRS), and assess its diagnostic accuracy in comparison to the Beck Depression Inventory (BDI). A total of 94 MS participants were classified as non-depressed (N = 44) or affected by mood disorder associated to MS with depressive manifestations (MSD-MDDM; N = 37) or with a major depression-like episode (MSD-MDL; N = 13). Each participant underwent a psychiatric interview, MSDRS, and BDI; diagnostic accuracy was evaluated using area under the ROC curve (AROC). The diagnostic accuracy of MSDRS and BDI was comparable when diagnosing both MSD-MDDM and MSD-MDL (AROC respectively 0.8998 and 0.8659); the MSDRS showed higher accuracy for the diagnosis of MSD-MDL (AROC respectively 0.9278 and 0.8314; p = .038). The MSDRS may be a reliable tool for the diagnosis of depression in MS.

  18. The influence of effusion rate and rheology on lava flow dynamics and morphology: A case study from the 1971 and 1988-1990 eruptions at Villarrica and Lonquimay volcanoes, Southern Andes of Chile

    NASA Astrophysics Data System (ADS)

    Castruccio, Angelo; Contreras, María Angélica

    2016-11-01

    We analyzed two historical lava flows from the Southern Andes of Chile: The lava flows from the 1971 Villarrica volcano eruption and the 1988-1990 Lonquimay volcano eruption. The 1971 lava flow has a volume of 2.3 × 107 m3, a maximum length of 16.5 km and was emplaced in two days, with maximum effusion rates of 800 m3/s. The lava has a mean width of 150 m and thicknesses that decrease from 10 to 12 m at 5 km from the vent to 5-8 m at the flow front. The morphology is mainly 'a'ā. The 1988-1990 lava flow has a volume of 2.3 × 108 m3, a maximum length of 10.2 km and was emplaced in 330 days, with peak effusion rates of 80 m3/s. The flow has a mean width of 600 m and thicknesses that increase from 10 to 15 m near the vent to > 50 m at the front. The morphology varies from 'a'ā in proximal sectors to blocky in the rest of the flow. We modelled the advance rate and thickness of these flows assuming two possible dynamical regimes: An internal rheology regime modelled as a Herschel-Bulkley (HB) fluid and a Yield Strength in the Crust (YSC) regime. We compared our results with the widely used Newtonian and Bingham rheologies. Our results indicate that the 1971 flow can be modelled either by the HB, Bingham or Newtonian rheologies using a single temperature, while the 1988-1990 flow was controlled by the YSC regime. Our analysis and comparison of models shows that care should be taken when modelling a lava flow, as different rheologies and assumptions can reach the same results in terms of advance rate and flow thickness. These examples suggest that the crustal strength should be taken into account in any model of lava flow advance.

  19. 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.

  20. 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

  1. Volcano Monitoring and Eruption Response in Japan

    NASA Astrophysics Data System (ADS)

    Nakada, S.; Morita, Y.

    2010-12-01

    magma storage, shape of conduit, etc) obtained through the results from the previous national project and the usage of the precise data set, for example, with bore-hole type and near-crater seismometers. The variety in the eruption style is controlled by the magma supply or intrusion rate and related degassing efficiency. We do not understand exactly what controls the magma supply/intrusion rate. In several volcanoes monitored densely, nearly steady-state magma ascent and eruption will be able to be simulated based on some substantial models. However, the sudden change in the magma supply/intrusion rate, which may trigger the abnormal event such as the Miyakejima eruption in 2000, cannot be modeled. The important issues of the next decade in the volcanological point of view may include an understanding of the mechanisms controlling the magma supply/intrusion rate.

  2. Syn- and post-eruptive erosion, gully formation, and morphological evolution of a tephra ring in tropical climate erupted in 1913 in West Ambrym, Vanuatu

    NASA Astrophysics Data System (ADS)

    Németh, Károly; Cronin, Shane J.

    2007-04-01

    Syn- and post-eruptive erosion of volcanic cones plays an important role in mass redistribution of tephra over short periods. Descriptions of the early stages of erosion of tephra from monogenetic volcanic cones are rare, particularly those with a well-constrained timing of events. In spite of this lack of data, cone morphologies and erosion features are commonly used for long-term erosion-rate calculations and relative age determinations in volcanic fields. This paper offers new observations which suggest differing constraints on the timing of erosion of a tephra ring may be operating than those conventionally cited. In 1913 a tephra ring was formed as part of an eruption in west Ambrym Island, Vanuatu and is now exposed along a continuous 2.5 km long coastal section. The ring surrounds an oval shaped depression filled by water. It is composed of a succession of a phreatomagmatic fall and base-surge beds, interbedded with thin scoriaceous lapilli units. Toward the outer edges of the ring, base-surge beds are gradually replaced in the succession by fine ash-dominated debris flows and hyperconcentrated flow deposits. The inter-fingering of phreatomagmatic deposits with syn-volcanic reworked volcaniclastic sediments indicates that an ongoing remobilisation of freshly deposited tephra was already occurring during the eruption. Gullies cut into the un-weathered tephra are up to 4 m deep and commonly have c. 1 m of debris flow deposit fill in their bases. There is no indication of weathering, vegetation fragments or soil development between the gully bases and the basal debris flow fills. Gully walls are steep and superficial fans of collapsed sediment are common. Most gullies are heavily vegetated although some active (ephemeral) channels occur. These observations suggest that the majority of the erosion of such tephra rings in tropical climates takes place directly during eruption and possibly for only a period of days to weeks afterward. After establishment of the

  3. 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...

  4. 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...

  5. Mode of Administration Effects in Psychopathology Assessment: Analyses of Gender, Age, and Education Differences in Self-Rated Versus Interview-Based Depression.

    PubMed

    Levin-Aspenson, Holly F; Watson, David

    2017-03-16

    Respondents may answer sensitive questions differently depending on the mode of assessment (e.g., questionnaire, interview). The possibility of differences in these mode effects across groups is an important assessment consideration given the implications for test-score validity and bias. Although differences in mode effects are highly relevant to issues in clinical assessment, research is limited and generally fails to make use of psychometrically sound methods. The present research argues for greater attention to demographic differences in mode effects with regard to the assessment of psychopathology. Analyses of differences in mode effects in depression assessment are presented for gender, age, and education based on data from 440 community adults. Depression symptom ratings from a structured clinical interview were regressed on a self-report state depression composite score; analyses tested for differences of intercept and slope across gender, age, and education. Neither slope nor intercept differences were found for gender, but intercept differences were obtained for both age and level of education. These results indicate that younger and better educated respondents receive somewhat lower than expected ratings of depression in interviews, given their level of self-rated symptoms. These findings suggest that use of a single mode of assessment over- or underpredicts depression in certain participants. More generally, they demonstrate the value of multimethod assessment of psychopathology and justify further inquiry into mode-effect differences in clinical assessment. (PsycINFO Database Record

  6. Erupting Volcano Mount Etna

    NASA Technical Reports Server (NTRS)

    2001-01-01

    An Expedition Two crewmember 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. 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.

  7. An erupted complex odontoma.

    PubMed

    Tozoglu, Sinan; Yildirim, Umran; Buyukkurt, M Cemil

    2010-01-01

    Odontomas are benign tumors of odontogenic origin. The cause of the odontoma is unknown, but it is believed to be hereditary or due to a disturbance in tooth development triggered by trauma or infection. Odontomas may be either compound or complex. Although these tumors are seen frequently, erupted odontomas are rare. The purpose of this study is to present a rare case of complex odontoma that erupted into the oral cavity.

  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. 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

  10. 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.

  11. Calorespirometry reveals that goldfish prioritize aerobic metabolism over metabolic rate depression in all but near-anoxic environments.

    PubMed

    Regan, Matthew D; Gill, Ivan S; Richards, Jeffrey G

    2017-02-15

    Metabolic rate depression (MRD) has long been proposed as the key metabolic strategy of hypoxic survival, but surprisingly, the effects of changes in hypoxic O2 tensions (PwO2 ) on MRD are largely unexplored. We simultaneously measured the O2 consumption rate (ṀO2 ) and metabolic heat of goldfish using calorespirometry to test the hypothesis that MRD is employed at hypoxic PwO2  values and initiated just below Pcrit, the PwO2 below which ṀO2  is forced to progressively decline as the fish oxyconforms to decreasing PwO2 Specifically, we used closed-chamber and flow-through calorespirometry together with terminal sampling experiments to examine the effects of PwO2  and time on ṀO2 , metabolic heat and anaerobic metabolism (lactate and ethanol production). The closed-chamber and flow-through experiments yielded slightly different results. Under closed-chamber conditions with a continually decreasing PwO2 , goldfish showed a Pcrit of 3.0±0.3 kPa and metabolic heat production was only depressed at PwO2  between 0 and 0.67 kPa. Under flow-through conditions with PwO2  held at a variety of oxygen tensions for 1 and 4 h, goldfish also initiated MRD between 0 and 0.67 kPa but maintained ṀO2  to 0.67 kPa, indicating that Pcrit is at or below this PwO2 Anaerobic metabolism was strongly activated at PwO2 ≤1.3 kPa, but only used within the first hour at 1.3 and 0.67 kPa, as anaerobic end-products did not accumulate between 1 and 4 h exposure. Taken together, it appears that goldfish reserve MRD for near-anoxia, supporting routine metabolic rate at sub-PcritPwO2  values with the help of anaerobic glycolysis in the closed-chamber experiments, and aerobically after an initial (<1 h) activation of anaerobic metabolism in the flow-through experiments, even at 0.67 kPa PwO2.

  12. How to compare scores from different depression scales: equating the Patient Health Questionnaire (PHQ) and the ICD-10-Symptom Rating (ISR) using Item Response Theory.

    PubMed

    Fischer, H Felix; Tritt, Karin; Klapp, Burghard F; Fliege, Herbert

    2011-12-01

    A wide range of questionnaires for measuring depression are available. Item Response Theory models can help to evaluate the questionnaires exceeding the boundaries of Classical Test Theory and provide an opportunity to equate the questionnaires. In this study after checking for unidimensionality, a General Partial Credit Model was applied to data from two different depression scales [Patient Health Questionnaire (PHQ-9) and ICD-10-Symptom Rating (ISR)] obtained in clinical settings from a consecutive sample, including 4517 observations from a total of 2999 inpatients and outpatients of a psychosomatic clinic. The precision of each questionnaire was compared and the model was used to transform scores based on the assumed underlying latent trait. Both instruments were constructed to measure the same construct and their estimates of depression severity are highly correlated. Our analysis showed that the predicted scores provided by the conversion tables are similar to the observed scores in a validation sample. The PHQ-9 and ISR depression scales measure depression severity across a broad range with similar precision. While the PHQ-9 shows advantages in measuring low or high depression severity, the ISR is more parsimonious and also suitable for clinical purposes. Furthermore, the equation tables derived in this study enhance the comparability of studies using either one of the instruments, but due to substantial statistical spread the comparison of individual scores is imprecise.

  13. 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.

  14. 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

  15. Increased depressive ratings in patients with hepatitis C receiving interferon-alpha-based immunotherapy are related to interferon-alpha-induced changes in the serotonergic system.

    PubMed

    Bonaccorso, Stefania; Marino, Valentina; Puzella, Antonella; Pasquini, Massimo; Biondi, Massimo; Artini, Marco; Almerighi, Cristiana; Verkerk, Robert; Meltzer, Herbert; Maes, Michael

    2002-02-01

    There is now evidence that repeated administration of interferon-alpha (IFN-alpha) to patients with chronic active hepatitis and cancers induces depressive symptoms. There is also evidence that induction of the cytokine network modulates the serotonergic system and that major depression is related to activation of the cytokine network and disturbances in the serotonergic metabolism. The aims of this study were to examine the effects of IFN-alpha-based immunotherapy on the development of depressive symptoms in relation to its effects on plasma tryptophan and kynurenine and serum serotonin (5-HT). Eighteen patients affected by chronic active hepatitis C were treated with IFN-alpha (3-6 million units subcutaneously three to six times a week for 6 months) and had measurements of the previous parameters before starting immunotherapy and 2, 4, 16, and 24 weeks later. Severity of depression and anxiety were measured with the Montgomery-Asberg Depression Rating Scale (MADRS) and the Hamilton Rating Scale for Anxiety (HAM-A) scale, respectively. Immunochemotherapy with IFN-alpha (1) significantly increased the MADRS and HAM-A scores and serum kynurenine concentrations and (2) significantly reduced plasma tryptophan and serum 5-HT concentrations. IFN-alpha-based immunotherapy significantly increased the kynurenine per tryptophan quotient, which estimates the activity of indoleamine 2,3-dioxygenase, the major tryptophan-catabolizing enzyme, which is induced by IFNs. There are significant relationships between the IFN-alpha-induced changes in the MADRS score and serum kynurenine (positive) and 5-HT (negative) concentrations. Immunotherapy with IFN-alpha significantly increases the severity of depressive symptoms. The latter is related to changes in the serotonergic system, such as depletion of serum 5-HT and induction of the catabolism of tryptophan to kynurenine. It is suggested that the IFN-alpha-induced changes in the serotonergic turnover could play a role in the

  16. 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…

  17. 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.

  18. Eruption Products and Collection Methods for the 2008 Summit Eruption of Kilauea Volcano, Hawai'i

    NASA Astrophysics Data System (ADS)

    Wooten, K. M.; Thornber, C. R.; Swanson, D. A.; Ellis, J. F.; Orr, T. R.; Patrick, M. R.; Rausch, J.

    2008-12-01

    After several weeks of elevated sulfur dioxide emissions at Kilauea's summit, a new fumarole appeared low on the southeast wall of Halema'uma'u Crater in mid-March 2008. At 0258 H.s.t. on March 19, an explosive eruption at Halema'uma'u's fumarole created a crater approximately 35 m across. Since that explosive eruption, a gas plume, with variable amounts of ash, has continuously emanated from the vent. Lithic debris was strewn over approximately 50 hectares, but no juvenile material was erupted during the March 19 event. On March 24, however, Pele's hair, Pele's tears, and glass-coated lithics were found on the crater's rim. These samples were the first juvenile material erupted at Kilauea's summit since 1982. After the March 19 explosive eruption, five more significant explosive eruptions have occurred, each of which erupted juvenile and lithic material. Several methods have been used to collect tephra from this eruption. A 10-station network of ash collectors was set up in an array to track changes in fallout from the continuous plume and to calculate a daily accumulation rate. Ash and tephra samples for petrologic and geochemical analysis are collected from wooden boxes placed along the crater's rim. Meter-scale squares on the ground downwind of the vent were cleared of older debris to help recognize new tephra. The samples are classified in 10 categories, based on a variety of characteristics, such as juvenile and lithic component, texture, and appearance. This classification scheme has been devised to help distinguish among the diverse suite of erupted material.

  19. 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.

  20. Rate of Chiari I malformation in children of mothers with depression with and without prenatal SSRI exposure.

    PubMed

    Knickmeyer, Rebecca C; Meltzer-Brody, Samantha; Woolson, Sandra; Hamer, Robert M; Smith, J Keith; Lury, Kenneth; Gilmore, John H

    2014-10-01

    Selective serotonin reuptake inhibitors (SSRIs) are frequently prescribed to pregnant women. Therefore, research on in utero exposure to SSRIs can be helpful in informing patients and clinicians. The aim of this retrospective two-cohort study was to determine whether there is a statistically significant increase in Chiari I malformations (CIM) in children exposed to SSRIs during pregnancy. A total of 33 children whose mothers received a diagnosis of depression and took SSRIs during pregnancy (SSRI-exposed cohort) were matched to 66 children with no history of maternal depression and no SSRI exposure. In addition, 30 children whose mothers received a diagnosis of depression, but did not receive antidepressants during pregnancy (history of maternal depression cohort), were matched to 60 children with no history of maternal depression and no SSRI exposure. Main outcome was presence/absence of CIM on MRI scans at 1 and/or 2 years of age. Scans were reviewed by two independent neuroradiologists who were blind to exposure status. The SSRI-exposed children were significantly more likely to be classified as CIM than comparison children with no history of maternal depression and no SSRI exposure (18% vs 2%, p=0.003, OR estimate 10.32, 95% Wald confidence limits 2.04-102.46). Duration of SSRI exposure, SSRI exposure at conception, and family history of depression increased the risk. The history of maternal depression cohort did not differ from comparison children with no history of maternal depression and no SSRI exposure in occurrence of CIM (7% vs 5%, p=0.75, OR estimate 1.44, 95% Wald confidence limits 0.23-7.85). Replication is needed, as is additional research to clarify whether SSRIs directly impact risk for CIM or whether this relationship is mediated by severity of depressive symptoms during pregnancy. We would discourage clinicians from altering their prescribing practices until such research is available.

  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. Agreement Between Self and Informant-Reported Ratings of Personality Traits: The Moderating Effects of Major Depressive and/or Panic Disorder

    PubMed Central

    Lieberman, Lynne; Gorka, Stephanie M.; Huggins, Ashley A.; Katz, Andrea C.; Sarapas, Casey; Shankman, Stewart A.

    2015-01-01

    Several personality traits are risk factors for psychopathology. As symptoms of psychopathology may influence self-rated personality, informant-reports of personality are also sometimes collected. However, little is known about self-informant agreement in individuals with anxiety and/or depression. We investigated whether self-informant agreement on positive and negative affectivity (PA and NA), and anxiety sensitivity differs for individuals with major depression (MDD) and/or panic disorder (PD, total n=117). Informant- and self-reported PA was correlated among those with MDD, but not those without MDD. Informant- and self-reported anxiety sensitivity was correlated among those with PD, but not those without PD. Informant- and self-reported NA was correlated irrespective of diagnosis. Results indicate that the agreement of self and informant-reported personality may vary as a function of depression and/or anxiety disorders. PMID:26658660

  4. High rates of comorbid depressive and anxiety disorders among women with premutation of the FMR1 gene.

    PubMed

    Kenna, Heather A; Tartter, Molly; Hall, Scott S; Lightbody, Amy A; Nguyen, Quynh; de los Angeles, C Paula; Reiss, Allan L; Rasgon, Natalie L

    2013-12-01

    Phenotypic variations are emerging from investigations of carriers of the fragile X mental retardation 1 (FMR1) premutation gene (55 to 200 CGG repeats). Initial studies suggest elevated psychiatric and reproductive system dysfunction, but have largely used self-reports for assessment of psychiatric history. The present study used diagnostic psychiatric interviews and assessed reproductive and menstrual history in women with FMR1 premutation. History of psychiatric diagnoses and data on reproductive functioning were collected in 46 women with FMR1 premutation who were mothers of at least one child with the fragile X full mutation. Results showed a significantly earlier age of menopause (mean age = 45.6 years) relative to the national average age of menopause (mean age = 51 years) and a high rate (76%) of lifetime depressive or anxiety history, with 43% of the overall sample reporting a comorbid history of both diagnoses. Compared to those free of psychiatric history, significantly longer premutation length was observed among women with psychiatric history after adjusting for age, with comorbid women having the highest number of CGG repeats (mean = 95.8) compared to women free of psychiatric history (mean = 79.9). Psychiatric history did not appear significantly related to reproductive system dysfunction, though results may have been obscured by the high rates of psychiatric dysfunction in the sample. These data add to the growing evidence base that women with the FMR1 premutation have an increased risk of psychiatric illness and risk for early menopause. Future investigations may benefit from inclusion of biochemical reproductive markers and longitudinal assessment of psychiatric and reproductive functioning.

  5. Patients’ perspectives on the use of the Montgomery-Asberg depression rating scale self-assessment version in primary care

    PubMed Central

    Wikberg, Carl; Pettersson, Agneta; Westman, Jeanette; Björkelund, Cecilia; Petersson, Eva-Lisa

    2016-01-01

    Objective The aim of the current study was to better understand how patients with depression perceive the use of MADRS-S in primary care consultations with GPs. Design Qualitative study. Focus group discussion and analysis through Systematic Text Condensation. Setting Primary Health Care, Region Västra Götaland, Sweden. Subjects Nine patients with mild/moderate depression who participated in a RCT evaluating the effects of regular use of the Montgomery-Åsberg Depression Self-assessment scale (MADRS-S) during the GP consultations. Main Outcome measure Patients’ experiences and perceptions of the use of MADRS-S in primary care. Results Three categories emerged from the analysis: (I) confirmation; MADRS-S shows that I have depression and how serious it is, (II) centeredness; the most important thing is for the GP to listen to and take me seriously and (III) clarification; MADRS-S helps me understand why I need treatment for depression. Conclusion Use of MADRS-S was perceived as a confirmation for the patients that they had depression and how serious it was. MADRS-S showed the patients something black on white that describes and confirms the diagnosis. The informants emphasized the importance of patient-centeredness; of being listened to and to be taken seriously during the consultation. Use of self-assessment scales such as MADRS-S could find its place, but needs to adjust to the multifaceted environment that primary care provides. Key Points Patients with depression in primary care perceive that the use of a self-assessment scale in the consultation purposefully can contribute in several ways. The scale contributes to Confirmation: MADRS-S shows that I have depression and how serious it is. Centeredness: The most important thing is for the GP to listen to and take me seriously. Clarification: MADRS-S helps me understand why I need treatment for depression. PMID:27804312

  6. 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.

  7. 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.

  8. 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

  9. 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.

  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. 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.

  12. 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.

  13. Eruption of Pele

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The eruption of Pele on Jupiter's moon Io. The volcanic plume rises 300 kilometers above the surface in an umbrella-like shape. The plume fallout covers an area the size of Alaska. The vent is a dark spot just north of the triangular-shaped plateau (right center). To the left, the surface is covered by colorful lava flows rich in sulfur.

  14. Review of eruptive activity at Tianchi volcano, Changbaishan, northeast China: implications for possible future eruptions

    NASA Astrophysics Data System (ADS)

    Wei, Haiquan; Liu, Guoming; Gill, James

    2013-04-01

    One of the largest explosive eruptions in the past several thousand years occurred at Tianchi volcano, also known as Changbaishan, on the China-North Korea border. This historically active polygenetic central volcano consists of three parts: a lower basaltic shield, an upper trachytic composite cone, and young comendite ash flows. The Millennium Eruption occurred between 938 and 946 ad, and was preceded by two smaller and chemically different rhyolitic pumice deposits. There has been at least one additional, small eruption in the last three centuries. From 2002 to 2005, seismicity, deformation, and the helium and hydrogen gas contents of spring waters all increased markedly, causing regional concern. We attribute this event to magma recharge or volatile exhalation or both at depth, followed by two episodes of addition of magmatic fluids into the overlying aquifer without a phreatic eruption. The estimated present magma accumulation rate is too low by itself to account for the 2002-2005 unrest. The most serious volcanic hazards are ash eruption and flows, and lahars. The available geological information and volcano monitoring data provide a baseline for comprehensive assessment of future episodes of unrest and possible eruptive activity.

  15. Reunion Island Volcano Erupts

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On January 16, 2002, lava that had begun flowing on January 5 from the Piton de la Fournaise volcano on the French island of Reunion abruptly decreased, marking the end of the volcano's most recent eruption. These false color MODIS images of Reunion, located off the southeastern coast of Madagascar in the Indian Ocean, were captured on the last day of the eruption (top) and two days later (bottom). The volcano itself is located on the southeast side of the island and is dark brown compared to the surrounding green vegetation. Beneath clouds (light blue) and smoke, MODIS detected the hot lava pouring down the volcano's flanks into the Indian Ocean. The heat, detected by MODIS at 2.1 um, has been colored red in the January 16 image, and is absent from the lower image, taken two days later on January 18, suggesting the lava had cooled considerably even in that short time. Earthquake activity on the northeast flank continued even after the eruption had stopped, but by January 21 had dropped to a sufficiently low enough level that the 24-hour surveillance by the local observatory was suspended. Reunion is essentially all volcano, with the northwest portion of the island built on the remains of an extinct volcano, and the southeast half built on the basaltic shield of 8,630-foot Piton de la Fournaise. A basaltic shield volcano is one with a broad, gentle slope built by the eruption of fluid basalt lava. Basalt lava flows easily across the ground remaining hot and fluid for long distances, and so they often result in enormous, low-angle cones. The Piton de la Fournaise is one of Earth's most active volcanoes, erupting over 150 times in the last few hundred years, and it has been the subject of NASA research because of its likeness to the volcanoes of Mars. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  16. 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

  17. Time Series of North Pacific Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Dehn, J.; Worden, A. K.; Webley, P. W.

    2011-12-01

    The record of volcanic eruptions was gathered from the 1986 eruption of Augustine Volcano to present for Alaska, Kamchatka and the Kuriles Islands. In this time over 400 ash producing eruptions were noted, and many more events that produced some other activity, e.g. lava, lahar, small explosion, seismic crisis. This represents a minimum for the volcanic activity in this region. It is thought that the records for Alaska are complete for this time period, but it is possible that activity in the Kuriles and Kamchatka could have been overlooked, particularly smaller events. For the Alaska region, 19 different volcanoes have been active in this time. Mt. Cleveland shows the most activity over the time period (40 % likely to have activity in a 3 month period), followed closely by Pavlof (34% likely)volcano. In Kamchatka only 7 volcanoes have been active, Shiveluch is the most active (83% likely) followed by Bezymianny and Kliuchevskoi volcanoes (tied at 60%). The Kuriles only has had 4 active volcanoes, and only 6 known eruptions. Overall this region is one of the most active in the world, in any 3 month period there is a 77% likelihood of volcano activity. For well instrumented volcanoes, the majority of activity is preceded by significant seismicity. For just over half of the events, explosive activity is preceded by thermal signals in infrared satellite data. Rarely (only about 5% of the time) is a stand alone thermal signal not followed within 3 months by an explosive eruption. For remaining events where an ash plume begins the activity, over 90% of the cases show a thermal signal the eruption. The volcanoes with the most activity are the least likely to produce large ash plumes. Conversely the volcanoes that erupt rarely often begin with larger ash producing events. Though there appears to be a recurrent progression of volcanic activity down the chain from east to west, this may be an artifact of several independent systems, each working at their own rate, that

  18. 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/ ...

  19. 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.

  20. Soil erosion rates in two karst peak-cluster depression basins of northwest Guangxi, China: Comparison of the RUSLE model with 137Cs measurements

    NASA Astrophysics Data System (ADS)

    Feng, Teng; Chen, Hongsong; Polyakov, Viktor O.; Wang, Kelin; Zhang, Xinbao; Zhang, Wei

    2016-01-01

    Reliable estimation of erosion in karst areas is difficult because of the heterogeneous nature of infiltration and sub-surface drainage. Understanding the processes involved is a key requirement for managing against karst rock desertification. This study used the revised Universal Soil Loss Equation (RUSLE) to estimate the annual soil erosion rates on hillslopes and compared them with 137Cs budget in the depressions at two typical karst peak-cluster depression basins in northwest Guangxi, southwestern China. Runoff plots data were used to calibrate the slope length factor (L) of the RUSLE model by adjusting the accumulated area threshold. The RUSLE model was sensitive to the value of the threshold and required DEMs with 1 m resolution, due to the discontinuous nature of the overland flow. The average annual soil erosion rates on hillslopes simulated by the RUSLE were 0.22 and 0.10 Mg ha- 1 y- 1 during 2006 through 2011 in the partially cultivated GZ1 and the undisturbed GZ2 basins, respectively. The corresponding deposition rates in the depressions agreed well with the 137Cs records when recent changes in precipitation and land use were taken into consideration. The study suggests that attention should be given to the RUSLE-L factor when applying the RUSLE on karst hillslopes because of the discontinuous nature of runoff and significant underground seepage during storm events that effectively reduces the effects of slope length.

  1. Eruption of magmatic foams on the Moon: Formation in the waning stages of dike emplacement events as an explanation of ;irregular mare patches;

    NASA Astrophysics Data System (ADS)

    Wilson, Lionel; Head, James W.

    2017-04-01

    Volcanic eruptions on the Moon take place in conditions of low gravity and negligible atmospheric pressure, very different from those on Earth. These differences lead to characteristic lunar versions of hawaiian and strombolian explosive activity, and to the production of unusual eruption products neither predicted nor observed on Earth in the terminal stages of eruptions. These include the unusual mounds and rough (hummocky, blocky) floors of some small-shield summit pit crater floors, elongate depressions and mare flows (similar to those named ;irregular mare patches;, IMPs, by Braden et al., 2014). We examine the ascent and eruption of magma in the waning stages of the eruptive process in small-shield summit pit crater floors and show that many IMP characteristics can be plausibly explained by basaltic magma behavior as the rise rate of the ascending magma slows to zero, volatiles exsolve in the dike and lava lake to form a very vesicular foam, and the dike begins to close. Stresses in the very vesicular and porous lava lake crust produce fractures through which the foam extrudes at a rate determined by its non-Newtonian rheology. Waning-stage extrusion of viscous magmatic foams to the surface produces convex mounds whose physical properties inhibit typical impact crater formation and regolith development, creating an artificially young crater retention age. This mechanism for the production and extrusion of very vesicular magmatic foams is also applicable to waning-stage dike closure associated with pit craters atop dikes, and fissure eruptions in the lunar maria, providing an explanation for many irregular mare patches. This mechanism implies that IMPs and associated mare structures (small shields, pit craters and fissure flows) formed synchronously billions of years ago, in contrast to very young ages (less than 100 million years) proposed for IMPs by some workers.

  2. 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.

  3. The Chaitén 2008 eruption: explosive eruption characteristics and tephra dispersal

    NASA Astrophysics Data System (ADS)

    Watt, S. F. L.; Pyle, D. M.

    2012-04-01

    of cloud aggregation processes, affecting rates of fine ash fallout. The complexity of the Chaitén fall deposit, resulting from a multi-phase eruption and changing wind patterns, could only be revealed through a combination of rapid field measurements of the distal deposit and modern satellite observations. The long-term preservation of this ash deposit is likely to be extremely sparse; such effects also limit the recognition of previous eruptions. The 2008 eruption was widely cited as the first at Chaitén for ~9000 years, but recent field data shows that much more recent eruptions have occurred. These were of similar magnitude to, and in some cases far larger than, the 2008 eruption. Each of these previous eruptions also sampled a homogeneous rhyolite magma stock, stored at depths of ~10 km beneath the volcano.

  4. High Rates of Depressive Symptoms among Senior High School Students Preparing for National University Entrance Examination in Turkey

    ERIC Educational Resources Information Center

    Yildirim, Ibrahim; Ergene, Tuncay; Munir, Kerim

    2007-01-01

    The purpose of the present study is to determine the prevalence of depressive symptoms among senior high school students preparing national university entrance examination (OSS) in Turkey. The authors conducted a survey during the second term of students' senior year at high school, a time when they were exposed to a stressful standardized…

  5. 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

  6. Can short-term heart rate variability be used to monitor fentanyl-midazolam induced changes in ANS preceding respiratory depression?

    PubMed

    Smith, Anne-Louise; Owen, Harry; Reynolds, Karen J

    2015-06-01

    Opioids have an occasional but high-risk side effect of respiratory depression. The detection of critical respiratory depression usually occurs after the event. Earlier detection would be beneficial in preventing increased morbidity and mortality of 0.01 % patients receiving analgesic opioids. Airway patency during inspiration requires vagal modulation. Regulation of the cardiovascular and respiratory centres may be coupled with a central mechanism that is indirectly measurable with heart rate variability (HRV). While opioids tend to increase parasympathetic tone, a decrease in airway stability could be due to a decrease in respiratory parasympathetic activity. Sympathetic arousal generated by apneic events may separately be recognised with short-term HRV. This pilot observational study examined the dynamic sympathovagal changes during fentanyl-midazolam induced respiratory depression on 10 subjects scheduled for minor surgery. A selection of HRV indices, able to work over sub-minute periods on non-stationary signals, were applied including a range of less common indices. Three analyses tested the effects: post-fentanyl, preceding the first central depression, and preceding obstruction of the upper airway. Statistical significance was assessed with overlap of bootstrap percentile confidence intervals for the median. A decrease in total variability, Lomb Total using the Lomb-Scargle method, is a positive finding for short-term HRV use in this study. No significant change before critical respiratory events was observed in traditional, spectral power, respiratory or other indices. One index, PolVar20, indicated a burst of sympathetic activity preceding respiratory depression similar to sleep apnoea arousals that restore airway patency. Before its usefulness in early detection of airway tone can be determined, PolVar20 requires further work: a statistical method for highly skewed distributions, auto adjustment for baseline variability, and detecting a range of

  7. Explosive dynamics of violent Strombolian eruptions: The eruption of Parícutin Volcano 1943 1952 (Mexico)

    NASA Astrophysics Data System (ADS)

    Pioli, L.; Erlund, E.; Johnson, E.; Cashman, K.; Wallace, P.; Rosi, M.; Delgado Granados, H.

    2008-07-01

    Violent Strombolian is a term that was originally used by MacDonald [Macdonald, G.A., 1972. Volcanoes, Prentice-Hall inc., Englewood Cliffs, New Jersey, 510 pp.] to describe energetic Strombolian eruptions such as some of the more explosive phases of the 1943-1952 eruption of Parícutin Volcano (Michoacán, central Mexico), eruptions that disperse 'showers of incandescent cinder and bombs…to heights of a few thousand feet' and during which 'a great black ash cloud rises above the volcano'. Here we re-examine accounts of the Parícutin eruption and compare them with new stratigraphic data and physical features of the tephra deposit to improve the definition of violent Strombolian activity and to better elucidate the mechanisms that can cause this distinctive eruptive style. We find characteristic violent Strombolian activity to be strongly pulsatory, with production of moderately high eruption columns (2-6 km) that eject abundant fine ash. Also characteristic is simultaneous lava effusion from lateral vents. At Parícutin, violent Strombolian activity occurred at magma eruption rates of 10 4 to 10 5 kg/s, intermediate between Strombolian and subplinian rates. A progressive decline in magma flux during the eruption led to a decrease in the relative proportion of both erupted tephra and glassy vesicular fragments in the fallout layers. Eruption characteristics can be explained by varying degrees of shallow gas segregation from water-rich basaltic magma that modulate both transitions between two-phase flow regimes in the upper conduit and effusion of degassed lava from the base of the cone.

  8. 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.

  9. Models of volcanic eruption hazards

    SciTech Connect

    Wohletz, K.H.

    1992-06-01

    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.

  10. 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.

  11. Mass and style of eruptions in experimental geysers

    NASA Astrophysics Data System (ADS)

    Toramaru, Atsushi; Maeda, Kazuki

    2013-05-01

    In the present study, we conducted laboratory experiments of geysers to reproduce the time predictability of natural geysers in Yellowstone and other geothermal areas. We measured pressure and temperature in a hot water chamber, flux from a cold water reservoir, and mass erupted by each eruption (total number of eruptions are up to 100), varying experimental conditions such as the heating rate, water quality, and system geometry. We observed two styles of eruptions, "jet" and "flow" depending on the maximum height reached. Under some conditions, only jet events occurred, while under other conditions, jet and flow events co-occurred. Based on the statistical analysis of the erupted mass, an experiment setup that produces only jet events exhibits a narrower frequency distribution with a relatively large average mass. As the proportion of flow events increases, the frequency distribution of the erupted mass widens with relatively small average mass. The temperature measurements indicated that jet-dominated experimental setups had smaller temperature fluctuations than flow-dominated setup. We proposed a triggering condition involving boiling of water that defined the onset of an eruption. We assumed two thresholds of the efficiency of decompression boiling that defined explosivity and eruption development on the basis of hydrodynamic energetics. Using the triggering condition and the two thresholds, to explain experimental correlations between erupted mass, eruption style, and the magnitude of thermal fluctuation, we conducted a Monte Carlo simulation in a square consisting of 256 × 256 parcels with the superheating temperature as a stochastic variable by a Gaussian probability density function (PDF). The results showed that when the PDF has a larger average and smaller standard deviation, the event tends to be explosive and large fraction of water is evacuated, as in jet events. Decreasing the average temperature or increasing the standard deviation of the PDF shifts

  12. Quantifying the eruption cycle at Axial Seamount using submarine geodesy

    NASA Astrophysics Data System (ADS)

    Nooner, S. L.; Chadwick, B.

    2011-12-01

    Bottom pressure instruments within the caldera of Axial Seamount recorded subsidence during eruptions in 1998 and again in April 2011, for a total repeat time of 13 years. We present here a summary of the vertical deformation history at Axial and describe what that tells us about changes in magma supply over an entire eruption cycle. Over the last 13 years we have used a combination of continuously recording bottom pressure recorder (BPR) instruments and campaign style mobile pressure recorder (MPR) surveys to document changes in the elevation of the caldera floor. These observations of caldera deformation directly reflect changes in the magmatic system throughout the entire volcanic eruption cycle. Rapid inflation of the volcano (>50 cm/yr) started immediately after the 1998 eruption and began slowing exponentially within a few months, ultimately transitioning to a constant linear inflation rate of 15 cm/yr that continued until the 2011 eruption. We interpret these two different inflation regimes as the surface manifestation of two entirely different recharge mechanisms within the magma chamber: 1) Short-duration poroelastic flow and viscoelastic relaxation immediately following eruption, and 2) Long-term linear recharge from the mantle. The second mechanism suggests that long-term flow rates from the mantle are controlled by permeability rather than pressure at Axial. Finally, we present evidence that the pattern of deformation at Axial can be used as a method of forecasting future eruptions here.

  13. 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.

  14. Brittle seismic damage before and after eruptions, worldwide statistical analyses: implications for prediction.

    NASA Astrophysics Data System (ADS)

    Schmid, Agathe; Grasso, Jean-Robert

    2010-05-01

    Recent studies suggested that the seismic events prior and after an eruption follow an Omori's law similar to the one observed for earthquakes with possible different exponent values (e.g., Lemarchand and Grasso, 2007). Given these similarities, we are interested in going further into the analogy between damage triggered by earthquake failure and eruption onset, by studying the damage of the upper crust contemporary to eruptions. First, using worldwide earthquakes and eruptions databases, we quantified the spatial scale involved in crust damage around eruptions, as a function of the size of volcanic events, i.e. as measured by VEI. Using the distribution of seismic events around the time of eruption onsets, we found that larger volumes are involved in the brittle crust damage for the largest eruption sizes. Second, we analyzed the analogy between eruptions and earthquakes regarding crust loading and discharge, thanks to patterns of seismicity around event times. For eruptions on a given volcano, evidences for crust loading have been highlighted thanks to seismicity up to ten days prior eruption time (e.g.,Voight, 1988; Kilburn, 2003; Chastin and Main, 2003; Collombet and Grasso, 2003). For worldwide eruptions, average seismicity around eruption time, shows direct and inverse Omori's law, the same way earthquakes do but with different values of exponents (Lemarchand and Grasso, 2007). Contrarily to earthquakes Omori's law, our preliminary analysis suggests the values of these exponents to possibly vary with the eruption sizes. Given that eruption processes generally show longer failure times than earthquake rupture propagation, we are interested in the mechanical responses of the brittle crust damages as a function of the forcing rate. It possibly argues for the eruption process to impact the brittle crust the same way than a slow earthquake, with a larger number of foreshocks than the regular earthquake. Implications for prediction of eruptions, regarding the size

  15. Embodied intervention reduce depression

    NASA Astrophysics Data System (ADS)

    Song, Dong-Qing; Bi, Xin; Fu, Ying

    2011-10-01

    To investigate the difference of the selected-rate of undergraduates' depression with respect to time, gender and scales and the intervention effect of embodied exercise, 201 Undergraduates were measured with Self-Rating Depression Scale and Beck Depression Inventory (BDI).The result shows there are significant difference of the selected-rates of undergraduates' depression resulted from long-time interval rather than from short-time interval and gender. After the intervention, the selected-rates are decreased and no significant difference has been found between the embodied groups and the controlled group. Only the embodied groups maintain the better effects of the intervention in the tracking. Also the result shows that only the participants of embodied groups obtain more positive emotional experience. We conclude that there is significant difference of selected-rate of undergraduates' depression on scales, and the embodied exercise can effectively reduce undergraduate's depression.

  16. Comparing the Hazards From Large Volcanic Eruptions and Impacting Asteroids

    NASA Astrophysics Data System (ADS)

    Mason, B. G.; Pyle, D. M.

    2003-12-01

    Explosive volcanic eruptions and asteroid impacts leave craters that allow direct comparison of the scale and frequency of these severe events. We have compiled data on large volcanic eruptions over the past 45 million years, and used this to develop an improved quantitative assessment of the frequency of large volcanic eruptions, and to make a comparative assessment of the relative likelihood of the Earth being affected by severe volcanic eruptions, and impact events of equal severity. In terms of volcanic activity, the expected frequency of explosive eruptions involving > 1015 kg of rock lies between 1.3 and 22 events per million years. For the events that form terrestrial craters with diameters of order 10 - 25 km, the thermal energy release (during a volcanic eruption) is of the same order of magnitude as the kinetic energy release (from an asteroid impact), and ca. 1021 - 1022 J (2 x 105 - 2 x 106 Mt equivalent of TNT). Over the past 5 Ma, volcanic activity dominates the production rate of craters < 45 km diameter. This suggests that over short timescales (< 1 Ma), destructive volcanic eruptions are more frequent than impact events of a similar energy. A better comparison of the primary effects of both phenomena may be realised by considering the area destroyed by shock waves (impactors) or hot pyroclastic deposits (volcanoes). Using simple scalings, we show that the primary area destroyed by an impactor is about ten times that for an eruption. Using this area as a measure of severity, we can show that for events with a return period of 100,000 years or less, there are considerably more eruptions of a given severity than there are impact events. Impactor events only dominate for return periods of > 200,000 - 500,000 years. We conclude that smaller (< 1012 kg, < 1 km diameter) near-earth orbiters pose a significantly smaller hazard to humans than the regional effects of large (1014 - 1015 kg) volcanic eruptions.

  17. Anatahan Eruption of May, 2003: Integrated Response of the MARGINS Community

    NASA Astrophysics Data System (ADS)

    Hilton, D. R.; Fischer, T. P.; Wiens, D. A.; Camacho, J. T.

    2003-12-01

    Following the May 10 eruption, the MARGINS office responded by authorizing helicopter surveillance of the eruption and ship deployment to visit Anatahan. The helicopter flights allowed for (a) visual inspection of the impact of the eruption, (b) identification of the source of the eruption (east crater), (c) collection of bombs and tephra from the eruption, and (d) deployment of a seismometer. The ship visit followed, and consisted of (a) maintenance and data retrieval from a previously-deployed seismic station, (b) collection of more samples, and (c) deployment of COSPEC instrumentation (for volatile flux measurement). The eruption has therefore presented the MARGINS community with an unique opportunity to integrate geophysical, geochemical and volcanological observations of an active, SiO2-rich volcano located on a targeted margin. This presentation will highlight on-going studies of the May event which will be presented in detail in the accompanying special session. Topics to be presented include (1) seismicity associated with the eruption, which was well monitored by a PASSCAL broadband seismograph fortuitously installed on Anatahan 4 days prior to the eruption, (2) geochemistry of the erupted products. This includes ICP analysis of the major and trace element chemistry, electron microprobe analysis on selected mineral phases, plus the isotope systematics (Sr-Nd-Pb-Hf-O-U-series) of selected samples, (3) volcanological observations on eruption initiation and evolution plus estimates of volatile flux rates within 11 days of the start of the eruption, and (4) hazard assessment of the eruption and mitigation strategies.

  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. Syn-eruptive CO2 Degassing of Submarine Lavas Flows: Constraints on Eruption Dynamics

    NASA Astrophysics Data System (ADS)

    Soule, S. A.; Boulahanis, B.; Fundis, A.; Clague, D. A.; Chadwick, B.

    2013-12-01

    At fast- and intermediate-spreading rate mid-ocean ridges, quenched lava samples are commonly supersaturated in CO2 with concentrations similar to the pressure/depth of shallow crustal melt lenses. This supersaturation is attributed to rapid ascent and decompression rates that exceed the kinetic rates of bubble nucleation and growth. During emplacement, CO2 supersaturated lavas experience nearly isothermal and isobaric conditions over a period of hours. A recent study has demonstrated systematic decreases in CO2 with increasing transport distance (i.e. time) along a single flow pathway within the 2005-06 eruption at the East Pacific Rise (~2500 m.b.s.l.). Based on analysis of vesicle population characteristics and complementary noble gas measurements, it is proposed that diffusion of CO2 into bubbles can be used as a basis to model the gas loss from the melt and thus place constraints on the dynamics of the eruption. We suggest that submarine lava flows represent a natural experiment in degassing that isolates conditions of low to moderate supersaturation and highlights timescales of diffusion and vesiculation processes that are relevant to shallow crustal and conduit processes in subaerial basaltic volcanic systems. Here we report a new suite of volatile concentration analyses and vesicle size distributions from the 2011 eruption of Axial Volcano along the Juan de Fuca Ridge (~1500 m.b.s.l.). The lava flows from this eruption are mapped by differencing of repeat high-resolution bathymetric surveys, so that the geologic context of the samples is known. In addition, in-situ instrument records record the onset of the eruption and place constraints on timing that can be used to verify estimates of eruption dynamics derived from degassing. This sample suite provides a comprehensive view of the variability in volatile concentrations within a submarine eruption and new constraints for evaluating models of degassing and vesiculation. Initial results show systematic

  1. 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

  2. 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.

  3. Luminous Blue Variable Eruptions Triggered and Powered by Binary Interaction

    NASA Astrophysics Data System (ADS)

    Kashi, Amit

    2010-12-01

    We suggest that major Luminous Blue Variable (LBV) eruptions are a result of a periastron passage interaction with the secondary star. The interaction must take place when the primary envelope is in an unstable phase. In our model the mass transferred to the secondary accounts for the energy and light curve of the eruption. We propose that all major LBV eruptions are triggered by stellar companions, and that in extreme cases a short duration event with a huge mass transfer rate can lead to a bright transient event on time scales of weeks to months (a `supernova impostor').

  4. 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

  5. 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)

  6. A 5000-year record of multiple highly explosive mafic eruptions from Gunung Agung (Bali, Indonesia): implications for eruption frequency and volcanic hazards

    NASA Astrophysics Data System (ADS)

    Fontijn, Karen; Costa, Fidel; Sutawidjaja, Igan; Newhall, Christopher G.; Herrin, Jason S.

    2015-07-01

    The 1963 AD eruption of Agung volcano was one of the most significant twentieth century eruptions in Indonesia, both in terms of its explosivity (volcanic explosivity index (VEI) of 4+) and its short-term climatic impact as a result of around 6.5 Mt SO2 emitted during the eruption. Because Agung has a significant potential to generate more sulphur-rich explosive eruptions in the future and in the wake of reported geophysical unrest between 2007 and 2011, we investigated the Late Holocene tephrostratigraphic record of this volcano using stratigraphic logging, and geochemical and geochronological analyses. We show that Agung has an average eruptive frequency of one VEI ≥2-3 eruptions per century. The Late Holocene eruptive record is dominated by basaltic andesitic eruptions generating tephra fall and pyroclastic density currents. About 25 % of eruptions are of similar or larger magnitude than the 1963 AD event, and this includes the previous eruption of 1843 AD (estimated VEI 5, contrary to previous estimations of VEI 2). The latter represents one of the chemically most evolved products (andesite) erupted at Agung. In the Late Holocene, periods of more intense explosive activity alternated with periods of background eruptive rates similar to those at other subduction zone volcanoes. All eruptive products at Agung show a texturally complex mineral assemblage, dominated by plagioclase, clinopyroxene, orthopyroxene and olivine, suggesting recurring open-system processes of magmatic differentiation. We propose that erupted magmas are the result of repeated intrusions of basaltic magmas into basaltic andesitic to andesitic reservoirs producing a hybrid of bulk basaltic andesitic composition with limited compositional variations.

  7. Volcanic eruptions on Io: Heat flow, resurfacing, and lava composition

    NASA Technical Reports Server (NTRS)

    Blaney, Diana L.; Johnson, Torrence V.; Matson, Dennis L.; Veeder, Glenn J.

    1995-01-01

    We model an infrared outburst on Io as being due to a large, erupting lava flow which increased its area at a rate of 1.5 x 10(exp 5)/sq m and cooled from 1225 to 555 K over the 2.583-hr period of observation. The inferred effusion rate of 3 x 10(exp 5) cu m/sec for this eruption is very high, but is not unprece- dented on the Earth and is similar to the high eruption rates suggested for early lunar volcanism. Eruptions occur approxi- mately 6% of the time on Io. These eruptions provide ample resurfacing to explain Io's lack of impact craters. We suggest that the large total radiometric heat flow, 10(exp 14) W, and the size and temperature distribution of the thermal anomalies (McEwen et al. 1992; Veeder et al. 1994) can be accounted for by a series of silicate lava flows in various stages of cooling. We propose that the whole suite of Io's currently observed thermal anomalies was produced by multiple, high-eruptive-rate silicate flows within the past century.

  8. Depression and HIV disease.

    PubMed

    Valente, Sharon M

    2003-01-01

    Depressive disorders are common among 20% to 32% of people with HIV disease but are frequently unrecognized. Major depression is a recurring and disabling illness that typically responds to medications, cognitive psychotherapy, education, and social support. A large percentage of the emotional distress and major depression associated with HIV disease results from immunosuppression, treatment, and neuropsychiatric aspects of the disease. People with a history of intravenous drug use also have increased rates of depressive disorders. Untreated depression along with other comorbid conditions may increase costly clinic visits, hospitalizations, substance abuse, and risky behaviors and may reduce adherence to treatment and quality of life. HIV clinicians need not have psychiatric expertise to play a major role in depression. Screening tools improve case finding and encourage early treatment. Effective treatments can reduce major depression in 80% to 90% of patients. Clinicians who mistake depressive signs and symptoms for those of HIV disease make a common error that increases morbidity and mortality.

  9. Postpartum Depression

    MedlinePlus

    ... Crying Reduced concentration Appetite problems Trouble sleeping Postpartum depression symptoms Postpartum depression may be mistaken for baby ... drugs, which can make mood swings worse Postpartum depression Postpartum depression is often treated with psychotherapy (also ...

  10. Atypical Depression

    MedlinePlus

    Diseases and Conditions Atypical depression By Mayo Clinic Staff Any type of depression can make you feel sad and keep you from enjoying life. However, atypical depression — also called depression with atypical features — means that ...

  11. Postpartum Depression

    MedlinePlus

    ... Education & Events Advocacy For Patients About ACOG Postpartum Depression Home For Patients Search FAQs Postpartum Depression Page ... Postpartum Depression FAQ091, December 2013 PDF Format Postpartum Depression Labor, Delivery, and Postpartum Care What are the ...

  12. Depression ratings, reported sexual risk behaviors, and methamphetamine use: latent growth curve models of positive change among gay and bisexual men in an outpatient treatment program.

    PubMed

    Jaffe, Adi; Shoptaw, Steven; Stein, Judith; Reback, Cathy J; Rotheram-Fuller, Erin

    2007-06-01

    Although the cessation of substance use is the principal concern of drug treatment programs, many individuals in treatment experience co-occurring problems such as mood disruptions and sexual risk behaviors that may complicate their recovery process. This study assessed relationships among dynamic changes tracked over time in methamphetamine use, depression symptoms, and sexual risk behaviors (unprotected anal intercourse) in a sample of 145 methamphetamine-dependent gay and bisexual males enrolled in a 16-week outpatient drug treatment research program. Participants were randomly assigned into 1 of 4 conditions: contingency management (CM), cognitive behavioral therapy (CBT; the control condition), combined CM and CBT, and a tailored gay-specific version of the CBT condition. Using latent growth curve models, the authors assessed the relationship of means (intercepts) and the slopes of the 3 measures of interest over time to test whether changes in methamphetamine use predicted declining rates of depression and risky sexual behavior in tandem. Participants with the greatest downward trajectory in methamphetamine use (urine verified) reported the greatest and quickest decreases in reported depressive symptoms and sexual risk behaviors. The control group reported the most methamphetamine use over the 16 weeks; the tailored gay-specific group reported a more rapidly decreasing slope in methamphetamine use than the other participants. Findings indicate that lowering methamphetamine use itself has a concurrent and synergistic effect on depressive symptoms and risky sexual behavior patterns. This suggests that some users who respond well to treatment may show improvement in these co-occurring problems without a need for more intensive targeted interventions.

  13. 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.

  14. 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.

  15. 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

  16. The staying power of pain. A comparison of torture survivors from Bosnia and Colombia and their rates of anxiety, depression and PTSD.

    PubMed

    Alexander, Abigail; Blake, Stacie; Bernstein, Michael A

    2007-01-01

    The article describes symptoms of anxiety, depression and PTSD among Bosnian (n=17) and Colombian (n=17) torture survivors served by the Florida Center for Survivors of Torture, a programme of Gulf Coast Jewish Family Services, Inc. Information from clients enrolled in the programme for six months or more was collated over a 14 month period in order to better prioritize and design services for the two distinct populations. On average, the Bosnians in this sample experienced torture approximately 14 years ago while the Colombians'experience was approximately six years ago. Types of torture experienced by clients are documented using HURIDOCS and the number of family and friends affected by extreme trauma are counted. Employment and education levels attained are also identified. Findings show that 100% of Bosnians are symptomatic for depression and over half possess symptoms of PTSD compared to 35% of Colombians for depression and 18% for PTSD, despite the differences in years since trauma occurred. High incidences of torture experienced by Bosnian clients and high numbers of family and friends affected support the high rates of symptoms. For the Colombian clients, high rates of employment and years of education, as well as earlier intervention, may contribute to their lower rates of symptoms. The two client groups are distinguished by the unique circumstances experienced by each, including punctuated wartime versus a prolonged insurgency, as well as the refugee versus asylum seeker experience. This exploratory project informs the torture treatment model while recognizing the importance of ethnic, political and cultural perspectives affecting the healing process.

  17. 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

  18. 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

  19. 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

  20. Calderas produced by hydromagmatic eruptions through permafrost in northwest Alaska

    NASA Technical Reports Server (NTRS)

    Beget, J. E.

    1993-01-01

    Most hydromagmatic eruptions on Earth are generated by interactions of lava and ground or surface water. This eruptive process typically produces craters 0.1-1 km in diameter, although a few as large as 1-2 km were described. In contrast, a series of Pleistocene hydromagmatic eruptions through 80-100-m-thick permafrost on the Seward Peninsula of Alaska produced four craters 3-8 km in diameter. These craters, called the Espenberg maars, are the four largest maars known on Earth. The thermodynamic properties of ground ice influence the rate and amount of water melted during the course of the eruption. Large quantities of water are present, but only small amounts can be melted at any time to interact with magma. This would tend to produce sustained and highly explosive low water/magma (fuel-coolant) ratios during the eruptions. An area of 400 km(sub 2) around the Alaskan maars shows strong reductions in the density of thaw lakes, ground ice, and other surface manifestations of permafrost because of deep burial by coeval tephra falls. The unusually large Espenberg maars are the first examples of calderas produced by hydromagmatic eruptions. These distinctive landforms can apparently be used as an indicator of the presence of permafrost at the time of eruption.

  1. 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

  2. Fixed drug eruption to tartrazine.

    PubMed

    Orchard, D C; Varigos, G A

    1997-11-01

    An 11-year-old girl with a recurrent fixed drug eruption to tartrazine on the dorsum of the left hand is presented. Oral provocation tests to both the suspected food, an artificially coloured cheese crisp, and to tartrazine were positive. This case highlights fire need to consider artificial flavours, colours and preservatives as potential culprits in classic drug eruptions.

  3. Violent strombolian and subplinian eruptions at Vesuvius during post-1631 activity

    NASA Astrophysics Data System (ADS)

    Arrighi, Simone; Principe, Claudia; Rosi, Mauro

    2001-06-01

    On the basis of historical chronicles and field investigations the tephrostratigraphic sequence of post-1631 activity of Vesuvius is reconstructed. It has been established that, during this period, in addition to numerous totally effusive eruptions and/or normal strombolian activity, 16 explosive events produced well-traceable tephra deposits in the area outside the Mount Somma caldera. Ages of tephra beds were established on the basis of stratigraphic relationships with historical lava flows and comparison with chroniclers information. The dispersal and lithological characteristics of tephra deposits combined with description of explosive activity lead to the identification of three styles: (a) periods of violent strombolian activity; (b) violent strombolian eruptions; and (c) subplinian eruptions. Violent strombolian eruptions and periods of discrete activity are characterized by the formation of lapilli falls from eruptive columns only some kilometers high. Subplinian eruptions are defined on the basis of their lapilli fall volumes which is of the order of 107 m3, on eruptive column heights of approximately 10 km, bt higher than 1.5, and mass discharged rate values not lower than 106 kg/s. During the first century of activity after the 1631 eruption, two periods of violent strombolian activity occurred at Vesuvius (1682-1707 and 1707-1719) preceded, and followed, by a series of violent strombolian eruptions (1660, 1682, 1707, 1723, 1730, 1790, 1872). Between 1730 and 1779 a relevant change in the eruptive style of Vesuvius occurred by an increase in the explosivity of the eruptions. During the past two centuries of activity, only a few eruptions reached subplinian magnitude and only five eruptions had a phreatomagmatic phase (1779, 1794, 1822, 1906, 1944). Therefore, the previously accepted model of cyclic activity, in which each cycle is closed by an important explosive eruption with phreatomagmatic characteristics, is unfounded. The tephrostratigraphy of the

  4. Violent strombolian and subplinian eruptions at Vesuvius during post-1631 activity

    NASA Astrophysics Data System (ADS)

    Alessandro, G.

    2001-05-01

    On the basis of historical chronicles and field investigations the tephrostratigraphic sequence of post-1631 activity of Vesuvius is reconstructed. It has been established that, during this period, in addition to numerous totally effusive eruptions and/or normal strombolian activity, 16 explosive events produced well-traceable tephra deposits in the area outside the Mount Somma caldera. Ages of tephra beds were established on the basis of stratigraphic relationships with historical lava flows and comparison with chroniclers information. The dispersal and lithological characteristics of tephra deposits combined with description of explosive activity lead to the identification of three styles: (a) periods of violent strombolian activity; (b) violent strombolian eruptions; and (c) subplinian eruptions. Violent strombolian eruptions and periods of discrete activity are characterized by the formation of lapilli falls from eruptive columns only some kilometers high. Subplinian eruptions are defined on the basis of their lapilli fall volumes which is of the order of 107 m3, on eruptive column heights of approximately 10 km, bt higher than 1.5, and mass discharged rate values not lower than 106 kg/s. During the first century of activity after the 1631 eruption, two periods of violent strombolian activity occurred at Vesuvius (1682-1707 and 1707-1719) preceded, and followed, by a series of violent strombolian eruptions (1660, 1682, 1707, 1723, 1730, 1790, 1872). Between 1730 and 1779 a relevant change in the eruptive style of Vesuvius occurred by an increase in the explosivity of the eruptions. During the past two centuries of activity, only a few eruptions reached subplinian magnitude and only five eruptions had a phreatomagmatic phase (1779, 1794, 1822, 1906, 1944). Therefore, the previously accepted model of cyclic activity, in which each cycle is closed by an important explosive eruption with phreatomagmatic characteristics, is unfounded. The tephrostratigraphy of the

  5. Deformation associated with the 2015 Eruption of Axial Seamount

    NASA Astrophysics Data System (ADS)

    Nooner, S. L.; Chadwick, W.; Caress, D. W.; Clague, D. A.; Paduan, J. B.; Yoerger, D.; Sasagawa, G. S.

    2015-12-01

    On April 24th 2015, an eruption began at Axial Seamount, a seafloor volcano located about 480 km west of the Oregon coast at the intersection of the Cobb hotspot and the Juan de Fuca Ridge. This eruption was first detected in real time by the newly operational Ocean Observatories Initiative cabled instrumentation at Axial (Delaney, AGU-2015, Wilcock, AGU-2015, Caplan-Auerbach, AGU-2015). Two prior eruptions have been observed since routine observations began in the 1990's, one in January 1998 and the other in April 2011. Precise water pressure measurements made on the volcano have documented an inflation/deflation cycle within Axial's summit caldera for the past 15 years. These data are now being supplemented by repeat bathymetric mapping by AUV. The long-term pattern appears to be "inflation predictable", in which eruptions are triggered at or near the same level of inflation. This pattern allowed us to successfully forecast in September 2014 that the next eruption was expected to occur at Axial sometime in 2015 (a 1-year time window). It is noteworthy that the rate of inflation between the 2011 and 2015 eruptions was about 4 times higher than between the 1998 and 2011 eruptions (60 cm/yr vs. 15 cm/yr). Subsidence at the caldera center began at 06:00 on 24 April (all times GMT) and amounted to 2.2 m by 02:00 on 25 April (20 hours in), 2.4 m by 00:00 on 28 April, and 2.45 m by 05 May when subsidence ended and re-inflation began (which has continued ever since). This amount of subsidence is similar to that observed during the 2011 eruption, but in 2015 the initial rate of subsidence was higher (11 cm/hr during the first 20 hours vs. 7 cm/hr in 2011) and the duration appears to have been longer (11 days vs. 6 days). Also, the 1998 and 2011 eruptions occurred along the southeastern edge of the caldera and along Axial's south rift zone, whereas the 2015 eruption occurred along the north rift zone (Kelley, AGU-2015). Here we present preliminary results of our August

  6. Magma flow, eruption column and magma pressure change during 2010 Eyjafjallajökull and 2011 Grímsvötn eruptions, Iceland: Constraints from volcano geodesy on physical models of eruptive processes

    NASA Astrophysics Data System (ADS)

    Sigmundsson, F.; Hreinsdottir, S.; Hooper, A. J.; Grapenthin, R.; Heimisson, E. R.; Ofeigsson, B.; Sturkell, E. C.; Roberts, M. J.; Gudmundsson, M. T.; Hoskuldsson, A.; Bjornsson, H.; Arason, P.; Parks, M.; Dumont, S.; Drouin, V.

    2014-12-01

    Ground deformation in relation to 2010 Eyjafjallajökull and 1998, 2004 and 2011 Grímsvötn eruptions in Iceland provide constraints on subsurface magma flow and pressure change. When compared with eruptive activity, eruption column and estimates of mass flow rate they can be used to constrain physical models of eruptive processes. The 1998 and 2004 Grímsvötn eruptions were captured by intermittent GPS observations but in 2011 the detailed temporal evolution of co-eruptive deformation was revealed by a kinematic 1 Hz solutions for the position of a single continuous GPS site on the volcano, supplemented with ground tilt observations. The observations can be explained by inflow of magma and pressure buildup between eruptions in a shallow chamber at about 1.7 km depth beneath the center of the Grímsvötn caldera complex, and pressure drop and magma outflow during eruptions. The rate of pressure change in the magma chamber correlates with the height of the volcanic plume over the course of the 2011 eruption. Peaks in activity relate to periods of rapid pressure drop in the chamber. GPS observations and interferometric analysis of satellite radar images from the TerraSAR-X satellite show that the explosive 2010 eruption at Eyjafjallajökull was on the other hand associated with gradual contraction of a source, distinct from pre-eruptive inflation sources at the volcano. For the initial 10-days of the summit eruption, a deflating sill source under the summit at about 5 km depth can explain the observed deformation, but then the source geometry appears to evolve. The rate of deflation was interrupted by inflow of new magma into the deflating source during the eruption in relation to peaks in explosive activity. The contrasting behavior of the two volcanoes is interpreted in terms of different magma plumbing systems of the volcanoes. In both cases, the erupted volume of magma is much larger than the inferred co-eruptive volume change, attributed to compressibility of

  7. 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

  8. Meprobamate-induced fixed drug eruption.

    PubMed

    Zaïem, Ahmed; Kaabi, Widd; Badri, Talel; Lakhoua, Ghozlane; Sahnoun, Rym; Kastalli, Sarrah; Daghfous, Riadh; Lakhal, Mohamed; El Aidli, Sihem

    2014-01-01

    Meprobamate is usually a safe drug prescribed for anxiety disorders. Fixed drug eruption (FDE) is an exceptional cutaneous adverse effect of this drug. We report a case of FDE induced by meprobamate with positive patch test. A 22-year-old woman was prescribed for depression meprobamate, aceprometazine, valpromide and lorazepam. On the second day of treatment, the patient presented red erythematous and pruriginous plaques in the limbs and the face. After stopping the previous treatment, the patient's lesions resolved completely within 3 weeks with residual pigmentation. One month later, patch tests were performed and were positive to meprobamate. Exceptional cases of FDE were reported in literature with meprobamate. None has reported the use of patch test to confirm the diagnosis.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Large and small volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Agust; Mohajeri, Nahid

    2013-04-01

    Despite great progress in volcanology in the past decades, we still cannot make reliable forecasts as to the likely size (volume, mass) of an eruption once it has started. Empirical data collected from volcanoes worldwide indicates that the volumes (or masses) of eruptive materials in volcanic eruptions are heavy-tailed. This means that most of the volumes erupted from a given magma chamber are comparatively small. Yet, the same magma chamber can, under certain conditions, squeeze out large volumes of magma. To know these conditions is of fundamental importance for forecasting the likely size of an eruption. Thermodynamics provides the basis for understanding the elastic energy available to (i) propagate an injected dyke from the chamber and to the surface to feed an eruption, and (ii) squeeze magma out of the chamber during the eruption. The elastic energy consists of two main parts: first, the strain energy stored in the volcano before magma-chamber rupture and dyke injection, and, second, the work done through displacement of the flanks of the volcano (or the margins of a rift zone) and the expansion and shrinkage of the magma chamber itself. Other forms of energy in volcanoes - thermal, seismic, kinetic - are generally important but less so for squeezing magma out of a chamber during an eruption. Here we suggest that for (basaltic) eruptions in rift zones the strain energy is partly related to minor doming above the reservoir, and partly to stretching of the rift zone before rupture. The larger the reservoir, the larger is the stored strain energy before eruption. However, for the eruption to be really large, the strain energy has to accumulate in the entire crustal segment above the reservoir and there will be additional energy input into the system during the eruption which relates to the displacements of the boundary of the rift-zone segment. This is presumably why feeder dykes commonly propagate laterally at the surface following the initial fissure

  15. Observations, stratigraphy and eruptive processes of the 1990 eruption of Kelut volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    Bourdier, Jean-Louis; Pratomo, Indyo; Thouret, Jean-Claude; Boudon, Georges; Vincent, Pierre M.

    1997-12-01

    The February 10, 1990 eruption of Kelut volcano (eastern Java) reportedly began with seven discrete, short-lived explosions between 11.41 and 12.35 local times. Deposits of this initial, phreatomagmatic stage include a basal ash-fall layer (unit A1), widespread pumice surge deposits (unit S) and related pisolitic ash layer (unit A2). The main, plinian phase of the eruption lasted about 4 hours from 12.35 and produced pumice-flow deposits (unit PF) overlain by a pumice fallout layer distributed mainly to the southwest (unit P), and intra-plinian scoria-flow deposits (unit SF). Uppermost scoria-rich ash fall layers (unit A3) likely relate to late, discrete eruptive pulses. A few small explosions resumed on February 11 and 12 leaving no recognizable deposit. An embryonic lava dome had formed in the crater bottom by April, then was submerged by the new crater lake. Destruction of the summit area resulted from emplacement of the pre-plinian pumice surge up to 4-5 km on the south and west flanks, and of the early plinian pumice flows up to 1-2 km radially from the crater, before these were channelized in the main valleys to further travel 3 km. Most of the 32 human deaths resulted from roof collapse under the load of fallout tephra beyond the devastated area, which had been evacuated before the eruption began. The eruption produced 0.13 km 3 of tephra, of which 0.12 km 3 represent the products of the plinian phase. The average eruptive rate of the plinian phase is estimated to have been ˜7.5×10 6 kg/s magma DRE. The pumice flows are interpreted to have been formed due to unsteadiness and low velocity of the eruptive column at the beginning of the plinian phase. The intra-plinian scoria flows incorporate either more degassed or colder juvenile magma; they were presumably erupted at the edge of the column, due to fluctuations in the mass flux and in pressure in the conduit.

  16. Subglacial Silicic Eruptions: Wet Cavities and Moist Cavities.

    NASA Astrophysics Data System (ADS)

    Stevenson, J. A.; McGarvie, D. W.; Gilbert, J. S.; Smellie, J. L.

    2007-05-01

    Comparing the deposits of subglacial eruptions with those of subaerial and subaqueous eruptions enables the influence of magma-water-ice interactions to be explored. In this presentation, the Icelandic subglacial rhyolite tuyas of Kerlingarfjöll and Prestahnúkur are compared with subaerial and subaqueous rhyolite formations at Sierra La Primavera, México. Prestahnúkur formed by the subglacial lava effusion and thick lava flows with steep termini are products of confinement by ice walls. Basal deposits of perlitised obsidian lobes suggest a water-saturated environment, and the extremely abundant microvesicular lava blocks surrounding these lobes and throughout the edifice are broadly similar to the carapaces of silicic lava domes at La Primavera known to have a subaqueous origin. Although bedded and sorted deposits are present at Prestahnúkur, they are trivial compared to the thick and extensive caldera-lake deposits of La Primavera, which even contain a "giant pumice" marker bed formed by the lake-wide deposition of once-bouyant blocks. The Kerlingarfjöll rhyolite tuyas formed during explosive subglacial eruptions. The first-erupted material forms structureless beds of phreatomagmatically-fragmented ash; ash from subaqueous eruptions at La Primavera is similarly fine grained, but in contrast is well-bedded (due to lacustrine deposition). Later-erupted material at Kerlingarfjöll typically consists of massive unconsolidated lapilli-tuffs. The lapilli themselves are similar to those within the well-sorted subaerially-formed pumice cones La Primavera, however Kerlingarfjöll's lapilli- tuffs have grain-size characteristics of proximal pyroclastic flows. These observations suggest that although similar fragmentation mechanisms operated in both locations, transport and consequent sorting was limited at Kerlingarfjöll. The different products of the two Icelandic subglacial tuyas are related to their different eruption rates and magma volatile contents. Melting of

  17. Earthquake-induced static stress change in promoting volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bonali, Fabio Luca; Tibaldi, Alessandro; Corazzato, Claudia

    2014-05-01

    The aim of this work is to study how earthquakes could favour new eruptions, focusing the attention on earthquake-induced static effects in two different case sites, where 9 seismic events with Mw ≥ 8 occurred in the last century: the Alaska-Aleutian and Chilean volcanic arcs. We followed a novel approach that resolves the earthquake-induced static stress change normal to the magma pathway of each volcano instead of considering the general crustal volume. We also considered other parameters that may contribute to control eruptions, such as magma composition and viscosity, magma chamber depth and local tectonic settings. The dataset includes a total of 51 eruptions following the earthquakes; 33 represent first new eruptions occurred at each single volcano. Comparison of the eruption rate before and after each earthquake suggests that 26 out of the 33 first new eruptions have a positive relation with the studied earthquakes; 13 out of 26 represent awakening events, which are first new eruptions occurred at volcanoes with non-continuous eruptive activity that had no eruptions in the five years before the earthquake. The sensitivity analysis performed for the 2010 Chile earthquake shows that the N-S- and NE-SW-striking magma pathways suffered a larger unclamping in comparison with those striking NW-SE and E-W. Magma pathway geometry contributes to control the magnitude of the static stress change induced by large earthquakes, with differences of up to 8 times among magma-feeding planes of different orientation at the same volcano. This range of diverse values is larger for the volcanoes closer to the epicentre. The possible error in the estimate of magma chamber depth has a minimum effect on the results since the sensitivity analysis shows that the range of stress changes with depth is about 1.5 orders of magnitude smaller than the range linked to variations in the magma pathway strike. Results suggest that unclamping effect promoted eruptions that occurred at non

  18. Will subglacial rhyolite eruptions be explosive or intrusive? Some insights from analytical models

    NASA Astrophysics Data System (ADS)

    Tuffen, H.; McGarvie, D. W.; Gilbert, J. S.

    Simple analytical models of subglacial eruptions are presented, which simulate evolving subglacial cavities and volcanic edifices during rhyolitic eruptions beneath temperate glaciers. They show that the relative sizes of cavity and edifice may strongly influence the eruption mechanisms. Intrusive eruptions will occur if the edifice fills the cavity, with rising magma quenched within the edifice and slow melting of ice. Explosive magma-water interaction may occur if a water- or steam-filled gap develops above the edifice. Meltwater is assumed to drain away continuously, but any gap above the edifice will be filled by meltwater or steam. Ductile roof closure will occur if the glacier weight exceeds the cavity pressure and is modelled here using Nye's law. The results show that the effusion rate is an important control on the eruption style, with explosive eruptions favoured by large effusion rates. The models are used to explain contrasting eruption mechanisms during various Quaternary subglacial rhyolite eruptions at Torfajökull, Iceland. Although the models are simplistic, they are first attempts to unravel the complex feedbacks between subglacial eruption mechanisms and glacier response that can lead to a variety of eruptive scenarios and associated hazards.

  19. 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.

  20. Rate of change in physical fitness and quality of life and depression following exercise training in patients with congestive heart failure.

    PubMed

    Smart, Neil A; Murison, Robert

    2013-01-01

    Exercise training appears to improve peak oxygen consumption (VO(2) ) and quality of life (QOL) in heart failure patients, although disease etiology, patient demographics and medication may alter the rate of adaptation. The authors sought to identify rate of change from baseline in fitness, QOL, and depression following exercise training in a cohort of patients with congestive heart failure. Thirty male systolic heart failure patients (aged 63.8±8.3 years, baseline peak VO(2) 12.2±4.8 mL/kg/min, left ventricular ejection fraction 28.2±9.4%, New York Heart Association class II/II 22/8) undertook 52 weeks of exercise training, 16 weeks as an outpatient and a further 36 weeks of home exercise. Peak VO(2) and QOL was measured using the Minnesota Living With Heart Failure (MLWHF) questionnaire and depression using the Hare-Davis scale. The authors analyzed the rate of change in peak VO(2) and MLWHF after grouping patients according to clinical, demographic, and pharmacologic characteristics. Peak VO(2) measurements varied over time, with no effect of disease pathology or β-blocker on peak VO(2) . The rate of change in physical MLWHF score was significantly greater (improved) during 0 to 16 weeks in patients with dilated pathology, but was not significantly affected by β-blocker use or age. The exercise training venue and supervision, or lack thereof, is the major determinant of adaptation to the intervention in heart failure patients, although age, β-adrenergic medication, and heart failure etiology also explain some of the variation in adaptive responses observed.

  1. Characterization of Solar Eruptions reported by EruptionPatrol

    NASA Astrophysics Data System (ADS)

    Hurlburt, Neal

    2015-04-01

    Observation of the solar atmosphere reveals a wide range of real and apparent motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advance our understanding the drivers of space weather. A method for automatically identifying eruptions near the solar surface (either from filaments or otherwise) has recently been developed and integrated into the Heliophysics Events Knowledgebase. Here we report on the EruptionPatrol module for identifying eruptions in data collected by the SDO/AIA instrument and on the characterization and analysis of its output. A cluster analysis on the time periods reported by EruptionPatrol demarcates several large-scale events spanning significant portions of the solar disk with lifetimes of up to six hours.

  2. An Analysis of Eruptions Detected by the LMSAL Eruption Patrol

    NASA Astrophysics Data System (ADS)

    Hurlburt, N. E.; Higgins, P. A.; Jaffey, S.

    2014-12-01

    Observations of the solar atmosphere reveals a wide range of real and apparent motions, from small scale jets and spicules to global-scale coronal mass ejections. Identifying and characterizing these motions are essential to advance our understanding the drivers of space weather. Automated and visual identifications are used in identifying CMEs. To date, the precursors to these — eruptions near the solar surface — have been identified primarily by visual inspection. Here we report on an analysis of the eruptions detected by the Eruption Patrol, a data mining module designed to automatically identify eruptions from data collected by Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA). We describe the module and use it both to explore relations with other solar events recorded in the Heliophysics Event Knowledgebase and to identify and access data collected by the Interface Region Imaging Spectrograph (IRIS) and Solar Optical Telescope (SOT) on Hinode for further analysis.

  3. Fixed drug eruption to sitagliptin.

    PubMed

    Gupta, Mrinal; Gupta, Anish

    2015-01-01

    Fixed drug eruption is a common adverse effect seen with various drugs notably antibiotics, antiepileptics and non-steroidal anti-inflammatory drugs. Herein we report a case of Sitagliptin induced fixed drug eruption in a 46 year old female who developed circumscribed, erythematous macules all over the body within one week of initiation of Sitagliptin. The lesions resolved with residual hyperpigmentation on cessation of the drug. The diagnosis was confirmed by an oral provocation test which led to a reactivation of the lesions. To the best of our knowledge, this is the first case of fixed drug eruption to Sitagliptin reported in the literature.

  4. Fixed drug eruption to propofol.

    PubMed

    Allchurch, L G V; Crilly, H

    2014-11-01

    We present a case of fixed drug eruption to propofol following a series of sedations of a patient for a number of day case procedures. The patient experienced oedema and blistering of his penis, increasing in severity and duration following each subsequent exposure. The diagnosis was confirmed by punch biopsy following an intravenous challenge test with propofol. Whilst reports of fixed drug eruptions to anaesthetic induction agents are uncommon, a number of drugs used commonly by anaesthetists are known triggers. We discuss fixed drug eruptions in relation to anaesthetic practice, aiming to raise awareness of this adverse drug reaction.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Depression (Major Depressive Disorder)

    MedlinePlus

    ... unrelated to the reason for your appointment Key personal information, including any major stresses or recent life ... accompanied by delusions or hallucinations, which may involve personal inadequacy or other negative themes Catatonia — depression that ...

  12. Tenofovir induced lichenoid drug eruption.

    PubMed

    Gupta, Mrinal; Gupta, Heena; Gupta, Anish

    2015-01-01

    Cutaneous adverse reactions are a common complication of anti-retroviral therapy. Tenofovir is a newer anti-retroviral drug belonging to the nucleotide reverse transcriptase inhibitor group. Systemic adverse effects like nausea, vomiting, diarrhea, hepatotoxicity and renal toxicity are common with tenofovir but cutaneous adverse effects are rare. Lichenoid drug eruptions are a common adverse effect seen with a large variety of drugs including antimalarials, antihypertensives, nonsteroidal anti-inflammatory drugs and diuretics. Lichenoid drug eruption is a rare cutaneous adverse effect of tenofovir with only a single case reported till date. Here, we report a case of tenofovir induced lichenoid drug eruption in a 54-year-old human immunodeficiency virus affected male who presented with generalized lichenoid eruption after 6 weeks of initiation of tenofovir and complete clearance on cessation of the drug.

  13. 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.

  14. Volcanology: Chronicling a medieval eruption

    NASA Astrophysics Data System (ADS)

    Ludlow, Francis

    2017-01-01

    The climatic response to the eruption of the Samalas Volcano in 1257 has been elusive. Medieval archives tell of a spatially variable reaction, with Europe and Japan experiencing severe cold compared to relative warmth in North America.

  15. 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

  16. Assessing eruption column height in ancient flood basalt eruptions

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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 ∼ 45 ° N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the ∼ 180km of known Roza fissure length could have supported ∼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 (∼ 66Ma) 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 flood basalt eruptions could have influenced

  17. Can tides influence volcanic eruptions?

    NASA Astrophysics Data System (ADS)

    Girona, T.; Huber, C.

    2015-12-01

    The possibility that the Moon-Sun gravitational force can affect terrestrial volcanoes and trigger eruptions is a controversial issue that has been proposed since ancient times, and that has been widely debated during the last century. The controversy arises mainly from two reasons. First, the days of initiation of eruptions are not well known for many volcanoes, and thus a robust statistical comparison with tidal cycles cannot be performed for many of them. Second, the stress changes induced by tides in the upper crust are very small (10-3 MPa) compared to the tensile strength of rocks (~ 10-1-10 MPa), and hence the mechanism by which tidal stresses might trigger eruptions is unclear. In this study, we address these issues for persistently degassing volcanoes, as they erupt frequently and thus the initiation time of a significant number of eruptions (>30) is well known in several cases (9). In particular, we find that the occurrence of eruptions within ±2 days from neap tides (first and third quarter moon) is lower than 34% (e.g., 29% for Etna, Italy; 28% for Merapi, Indonesia), which is the value expected if eruptions occur randomly with no external influence. To understand this preference for erupting far away from neap tides, we have developed a new lumped-parameter model that accounts for the deformation of magma reservoirs, a partially open conduit, and a gas layer where bubbles accumulate beneath volcanic craters before being released. We demonstrate that this system reservoir-conduit-gas layer acts as an amplifier of the tidal stresses, such that, when a volcano approaches to a critical state, the gas overpressure beneath the crater can reach up to several MPa more during a spring tide (full and new moon) than during a neap tide. This amplification mechanism can explain why active volcanoes are sensitive to the moon cycles.

  18. 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.

  19. A statistical analysis of eruptive activity on Mount Etna, Sicily

    NASA Astrophysics Data System (ADS)

    Smethurst, Lucy; James, Mike R.; Pinkerton, Harry; Tawn, Jonathan A.

    2009-10-01

    A rigorous analysis of the timing and location of flank eruptions of Mount Etna on Sicily is important for the creation of hazard maps of the densely populated area surrounding the volcano. In this paper, we analyse the temporal, volumetric and spatial data on eruptive activity on Etna. Our analyses are based on the two most recent and robust historical data catalogues of flank eruption activity on Etna, with one from 1669 to 2008 and the other from 1610 to 2008. We use standard statistical methodology and modelling techniques, though a number of features are new to the analysis of eruption data. Our temporal analysis reveals that flank eruptions on Mount Etna between 1610 and 2008 follow an inhomogeneous Poisson process, with intensity of eruptions increasing nearly linearly since the mid-1900s. Our temporal analysis reveals no evidence of cyclicity over this period. An analysis of volumetric lava flow rates shows a marked increase in activity since 1971. This increase, which coincides with the formation of the Southeast Crater (SEC), appears to be related to increased activity on and around the SEC. This has significant implications for hazard analysis on Etna.

  20. Polymorphous light eruption.

    PubMed

    Hölzle, E; Plewig, G; von Kries, R; Lehmann, P

    1987-03-01

    Polymorphous light eruption (PLE) is a common photodermatosis of unknown etiology. It afflicts mainly fair-skinned patients, with a preponderance of young females. There is, however, no absolute restriction as to age, sex, or race. Clinical variants include the papular, vesiculo-bullous, and hemorrhagic variety, as well as plaque, erythema multiforme-like, and insect bite (strophulus)-like types. Skin lesions appear only in certain exposed areas hours or a few days after intense sunshine, and are nearly always monomorphous in the same patient. The rash subsides spontaneously within several days without leaving scars. The histopathologic picture is characteristic and shows a perivascular lymphocytic infiltrate in the upper and middle corium with subepidermal edema, vacuolization of basal cells, and spongiosis in the lower epidermis. The most important differential diagnoses are solar urticaria, photosensitive erythema multiforme, and lupus erythematosus. The action spectrum of PLE is under debate. Reproduction of skin lesions has been reported with UVB, UVA, and, rarely, visible light, with UVA probably being the most effective part of the spectrum. More important than treatment of PLE is prophylaxis. UVA- and UVB-effective sunscreens are of some help. Phototherapy and especially photochemotherapy (psoralen + UVA; PUVA) offer effective ways to decrease light sensitivity. Systemic treatment with chloroquine or beta-carotene has been disappointing.

  1. Models of ice melting and edifice growth at the onset of subglacial basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Tuffen, Hugh

    2007-03-01

    Models of the early stages of basaltic eruptions beneath temperate glaciers are presented that consider the evolving sizes of volcanic edifices emplaced within subglacial cavities. The cavity size reflects the competing effects of enlargement by melting and closure by downward ductile deformation of the ice roof, which occurs when the cavity pressure is less than glaciostatic due to meltwater drainage. Eruptions of basaltic magma from fissures and point sources are considered, which form either hemicylindrical or hemispherical cavities. The rate of roof closure can therefore be estimated using Nye's law. The cavity size, edifice size, and depth of meltwater above the edifice are predicted by the model and are used to identify two potential eruption mechanisms: explosive and intrusive. When the cavity is considerably larger than the edifice, hydroclastic fragmentation is possible via explosive eruptions, with deposition of tephra by eruption-fed aqueous density currents. When the edifice completely fills the cavity, rising magma is likely to quench within waterlogged tephra in a predominantly intrusive manner. The models were run for a range of magma discharge rates, ice thicknesses and cavity pressures relevant to subglacial volcanism in Iceland. Explosive eruptions occur at high magma discharge rates, when there is insufficient time for significant roof closure. The models correctly predict the style of historic and Pleistocene subglacial fissure eruptions in Iceland and are used to explain the contrasting sedimentology of basaltic and rhyolitic tuyas. The models also point to new ways of unraveling the complex coupling between eruption mechanisms and glacier response during subglacial eruptions.

  2. 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.

  3. Basaltic fissure eruptions, plume heights, and atmospheric aerosols

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.; Wolff, J. A.; Self, S.; Rampino, M. R.

    1986-01-01

    Convective plumes that rise above Hawaiian-style fire fountains consist of volcanic gases, aerosols, fine ash, and entrained heated air. Plume theory has been applied to observational estimates of the rate of thermal energy release from large fire fountains. The theoretically predicted heights of maintained plumes agree very well with the heights found from actual observations. Predicted plume heights for both central-vent (point-source) and fissure (line-source) eruptions indicate a stratospheric penetration by plumes that form over vents with very high magma-production rates. Flood basalt fissure eruptions that produce individual lava flows with volumes greater than 100 cu km at very high mass eruption rates are capable of injecting large quantities of sulfate aerosols into the lower stratosphere, with potentially drastic short-term atmospheric consequences, like acid precipitation, darkening of the sky, and climatic cooling.

  4. Linking Texture and Degassing in Mildly Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Krans, S. R.; Cameron, B. I.

    2011-12-01

    The explosivity of volcanic eruptions depends on the concentration of volatiles dissolved in magma, the degree magma degasses, and the ascent rate. The interaction of magma and groundwater during phreatomagmatic eruptions arrests magma degassing leading to higher volatile contents, lower vesicularity, fewer microlites in eruptive products, and a more explosive eruptive style. Variations in texture and volatile concentration have been studied in eruptive products, but rarely in concert. Chemically, the degree of degassing can be interpreted by comparing the concentration of volatiles (H2O, CO2, S, and Cl) measured in olivine hosted melt inclusions to the concentration of volatiles found in the matrix glass. Textural evidence for degassing can be determined from the size and concentration of vesicles, as well as the crystallinity, crystal size, and area density of microlites found in juvenile clasts. This study presents both textural and chemical data for two mafic monogenetic cones of contrasting eruptive style. The primary objectives are to assess consistency between the methods and elucidate eruption dynamics. Scoria was collected from multiple stratigraphic levels at Jiloa cinder cone and Cerro San Carlos maar near Managua, Nicaragua. Volatile concentrations (H2O, CO2, S and Cl) in matrix glass and olivine hosted melt inclusions were collected by electron microprobe and Fourier Transform Infrared (FTIR) microspectrometry. Volatile concentrations were slightly higher in the maar scoria (S>100ppm and H2O>0.09wt%) than scoria collected from the cinder cone (S<60ppm and H2O ~0.09wt%). SEM images show that vesicularity and the abundance of microlites in scoria varies between the two cones and may reflect the degree of degassing and degassing-induced crystallization prior to fragmentation. Digital processing of these images will be performed in order to quantify vesicularity and area density of microlites in scoria. A comparison of chemical and textural analyses will

  5. 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.

  6. 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 ...

  7. 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 ...

  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. Resting, and rate-dependent depression of Vmax of guinea-pig ventricular action potentials by amiodarone and desethylamiodarone.

    PubMed Central

    Pallandi, R. T.; Campbell, T. J.

    1987-01-01

    1 The cellular electrophysiological effects of amiodarone and its metabolite desethylamiodarone (DEA) were studied in guinea-pig ventricular myocardium by use of standard microelectrode techniques. 2 Both compounds produced significant increases in action potential duration (Class III antiarrhythmic effect) and decreases in maximum rate of depolarization (Class I effect), at clinically relevant concentrations. 3 The Class I effects were rate-dependent, with small (0-16%) falls in maximum depolarization rate in the absence of stimulation ('resting block') and progressively larger effects at decreasing interstimulus intervals (range 1200-300 ms). 4 The kinetics of onset and offset of the Class I effect in response to a step change in driving rate were quite fast for both drugs (comparable to those reported for Class Ib agents). 5 It is concluded that this unique combination of Class III action plus Class I effects with fast onset and offset kinetics may help explain the great efficacy of amiodarone in antiarrhythmic therapy. PMID:3664094

  10. 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.

  11. 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.

  12. Climate effects of high-latitude volcanic eruptions: Role of the time of year

    NASA Astrophysics Data System (ADS)

    Kravitz, Ben; Robock, Alan

    2011-01-01

    We test how the time of year of a large Arctic volcanic eruption determines the climate impacts by conducting simulations with a general circulation model of Earth's climate. For eruptions injecting less than about 3 Tg of SO2 into the lower stratosphere, we expect no detectable climatic effect, no matter what the season of the eruption. For an injection of 5 Tg of SO2 into the lower stratosphere, an eruption in the summer would cause detectable climate effects, whereas an eruption at other times of the year would cause negligible effects. This is mainly due to the seasonal variation in insolation patterns and sulfate aerosol deposition rates. In all cases, the sulfate aerosols that form get removed from the atmosphere within a year after the eruption by large-scale deposition. Our simulations of a June eruption have many similar features to previous simulations of the eruption of Katmai in 1912, including some amount of cooling over Northern Hemisphere continents in the summer of the eruption, which is an expected climate response to large eruptions. Previous Katmai simulations show a stronger climate response, which we attribute to differences in choices of climate model configurations, including their specification of sea surface temperatures rather than the use of a dynamic ocean model as in the current simulations.

  13. Improvement in identification of multivessel disease after acute myocardial infarction following stress-recovery analysis of ST depression in the heart rate domain during exercise.

    PubMed

    Bigi, R; Maffi, M; Occhi, G; Bolognese, L; Pozzoni, L

    1994-09-01

    The demonstration of extensive coronary artery disease (CAD) after acute myocardial infarction (AMI) has important prognostic implications. Exercise-induced ST segment depression is commonly used for detecting the presence of CAD and evaluating its extension. However, even though there have been many attempts to increase its diagnostic yield, the accuracy of the electrocardiographic signal for identifying multivessel disease (MVD) is relatively low, particularly in post-MI patients. The aim of this study was to evaluate the ability of a simple index, combining information on the amount and kinetics of ST depression in the heart rate domain during exercise and recovery, to identify MVD after AMI. Seventy patients (mean age 53.4 years) underwent a bicycle, symptom-limited exercise stress test and coronary angiography 2-3 weeks and 6 weeks respectively, after uncomplicated AMI while cardioactive therapy was discontinued. After obtaining a computer-derived measurement of ST levels based on incremental averaging of normal complexes, the area subtended to baseline and limited by the ST trend against heart rate during both exercise (A1) and recovery (A2) was calculated. The difference (A1-A2) was defined as the 'Stress-Recovery Index' (SRI) and dichotomized, by means of receiver-operating characteristics curve analysis, at 5 mm x beats.min-1 to define an increased risk of MVD. The SRI of patients with MVD was significantly lower than that of patients with single vessel disease. The sensitivity of SRI < -5 mm x beats.min-1 (65%) for predicting MVD was significantly higher than that obtained by other conventional parameters, without appreciable loss of specificity (81%).(ABSTRACT TRUNCATED AT 250 WORDS)

  14. 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.

  15. Ascent velocity and dynamics of the Fiumicino mud eruption, Rome, Italy

    NASA Astrophysics Data System (ADS)

    Vona, A.; Giordano, G.; De Benedetti, A. A.; D'Ambrosio, R.; Romano, C.; Manga, M.

    2015-08-01

    In August 2013 drilling triggered the eruption of mud near the international airport of Fiumicino (Rome, Italy). We monitored the evolution of the eruption and collected samples for laboratory characterization of physicochemical and rheological properties. Over time, muds show a progressive dilution with water; the rheology is typical of pseudoplastic fluids, with a small yield stress that decreases as mud density decreases. The eruption, while not naturally triggered, shares several similarities with natural mud volcanoes, including mud componentry, grain-size distribution, gas discharge, and mud rheology. We use the size of large ballistic fragments ejected from the vent along with mud rheology to compute a minimum ascent velocity of the mud. Computed values are consistent with in situ measurements of gas phase velocities, confirming that the stratigraphic record of mud eruptions can be quantitatively used to infer eruption history and ascent rates and hence to assess (or reassess) mud eruption hazards.

  16. 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.

  17. 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

  18. Dental eruption in afrotherian mammals

    PubMed Central

    Asher, Robert J; Lehmann, Thomas

    2008-01-01

    Background Afrotheria comprises a newly recognized clade of mammals with strong molecular evidence for its monophyly. In contrast, morphological data uniting its diverse constituents, including elephants, sea cows, hyraxes, aardvarks, sengis, tenrecs and golden moles, have been difficult to identify. Here, we suggest relatively late eruption of the permanent dentition as a shared characteristic of afrotherian mammals. This characteristic and other features (such as vertebral anomalies and testicondy) recall the phenotype of a human genetic pathology (cleidocranial dysplasia), correlations with which have not been explored previously in the context of character evolution within the recently established phylogeny of living mammalian clades. Results Although data on the absolute timing of eruption in sengis, golden moles and tenrecs are still unknown, craniometric comparisons for ontogenetic series of these taxa show that considerable skull growth takes place prior to the complete eruption of the permanent cheek teeth. Specimens showing less than half (sengis, golden moles) or two-thirds (tenrecs, hyraxes) of their permanent cheek teeth reach or exceed the median jaw length of conspecifics with a complete dentition. With few exceptions, afrotherians are closer to median adult jaw length with fewer erupted, permanent cheek teeth than comparable stages of non-afrotherians. Manatees (but not dugongs), elephants and hyraxes with known age data show eruption of permanent teeth late in ontogeny relative to other mammals. While the occurrence of delayed eruption, vertebral anomalies and other potential afrotherian synapomorphies resemble some symptoms of a human genetic pathology, these characteristics do not appear to covary significantly among mammalian clades. Conclusion Morphological characteristics shared by such physically disparate animals such as elephants and golden moles are not easy to recognize, but are now known to include late eruption of permanent teeth, in

  19. A Population Study of Solar Eruptive Events

    NASA Astrophysics Data System (ADS)

    Young, C. A.

    2014-12-01

    Solar flares, coronal mass ejections (CMEs) and solar energetic particles (SEPs) are all manifestations of solar eruptive events (SEEs). The most energetic of these events pose the greatest threat to our technological society but understanding their nature and predicting their occurence rate is challenging due to their relative rarity. To better understand the nature of such events requires knowledge of their parent populations from the smallest to the largest. We revisit the populations of these events and present a preliminary analysis of their characteristics and the relationships between flare, CME and SEP distributions.

  20. 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

  1. Deformation, lava dome evolution, and eruption cyclicity at Merapi volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    Young, Kirby D.

    Deformation monitoring results are reported here for the period 1988-1998 at Merapi volcano, one of the most active and dangerous volcanoes in Indonesia. Comprehensive databases of various geophysical parameters were concurrently studied and analyzed to 2000, and similar data were subsequently considered during periods of eruption crisis in 2001 and 2006. Of particular emphasis was the study of lava eruption rates based on dome volume estimates and seismic proxies for dome collapse volumes. The detailed study period of deformation includes a major resumption in lava effusion in January 1992 and major dome collapses in November 1994, January 1997, and July 1998. Monitoring techniques employed in the field are of two types. Translational movements were recorded via electronic distance measurements (EDM) on a summit trilateration network, slope distance changes measured to the upper flanks, and other data collected from 1988 to 1995. Tilt changes were detected by a summit and flank network of tilt stations that operated at various times from 1993 to 1998. A major consequence of the deformation results is the documentation of a significant 4-year period of deformation precursory to the 1992 eruption. Cross-crater strain rates accelerated from less than 3 x 10-6/day between 1988 and 1990 to more than 11 x 10-6/day just prior to the January 1992 activity, representing a general, asymmetric extension of the summit during highlevel conduit pressurization. After the vent opened and effusion of lava resumed, strain occurred at a much reduced rate of less than 2 x 10-6/day. The Gendol breach, a pronounced depression formed by the juxtaposition of old lava coulees on the southeast flank, functioned as a major displacement discontinuity. An elevated phase of magma production with respect to the long-term rate for the 20th Century characterized the activity at Merapi volcano, Central Java/Yogyakarta, Indonesia, for the period 1992-2006. Most large (0.2 - 3.4 x 106 m3) dome

  2. Rise and Collapse of Volcanic Plumes Produced By Explosive Basaltic Fissure Eruptions

    NASA Astrophysics Data System (ADS)

    Paillat, S.; Kaminski, E. C.

    2014-12-01

    Explosive basaltic fissure eruptions, which release large amounts of sulfur gases in the atmosphere, can have a big impact on climate. The effect on climate depends on the rate of gas injection above the tropopause. The key parameter is the height reached by the eruptive plume as a function of mass flux and entrainment rate. We propose a model of entrainment in 2D volcanic plumes based on lab scale experiments on turbulent jets and plumes. In this model, entrainment varies with the Richardson number and we predict that the height of the column critically depends on the source buoyancy flux determined by the eruptive temperature and the amount of gas in the volcanic mixture at the vent. We obtain that "hot" basaltic planar plumes form stable eruptive columns, even for large eruption rates. Only if fragmentation is not efficient enough, the column collapse will prevent the injection of gas in the stratosphere.

  3. Automated detection of solar eruptions

    NASA Astrophysics Data System (ADS)

    Hurlburt, N.

    2015-12-01

    Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections (CMEs). Identifying and characterizing these motions are essential to advancing our understanding of the drivers of space weather. Both automated and visual identifications are currently used in identifying Coronal Mass Ejections. To date, eruptions near the solar surface, which may be precursors to CMEs, have been identified primarily by visual inspection. Here we report on Eruption Patrol (EP): a software module that is designed to automatically identify eruptions from data collected by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA). We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15 Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/s and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.

  4. 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

  5. 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

    2015-05-18

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  7. Dynamics of eruptive pulses - A case study of the second explosive phase of the 2010 Eyjafjallajökull eruption (Iceland)

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Current ash plume models of long-lived eruptions usually consider sustained ash plumes to be a continuous steady emission of tephra at the volcanic vent. The 2010 eruption of Eyjafjallajökull volcano, however, often displayed pulsating activity, where emissions from the vent occurred by frequent but discrete bursts (with pulses in the order of seconds) that merged at higher altitude in a sustained eruption column. High resolution near-field video recordings of the vents, taken from a distance of ~850 m during the second explosive phase from 8 - 10 May and supplemented by aerial observations, were used as a case study to describe the mechanism of such pulsating eruptions. The dynamics of discrete pressurized jets were characterized and their pressure history quantified between discharge from vent until they reached the height of transition at ~100 m, where the expanding regime turned into a convective buoyant one. It is suggested that during the analyzed initial expansion phase of eruption, a rapid decompression of the pulses caused a significant decrease in particle volumetric concentration within the jets, allowing and enhancing further-up air entrainment and buoyancy and leading to the establishment of dilute ash plumes that eventually merged and form the quasi-continuous eruption column. Based on the results and conclusions of our case study we examine how to link the eruption source parameters of multiple discrete expansive jets to the over-all mass eruption rate derived by 'classical' continuous ash plume models (being in the order of ~104 kg/s). Furthermore, the implications for real-time assessment by using near-field monitoring systems under pulsatory eruption conditions are discussed. Finally, the expansion dynamics of the analyzed pulses are compared to those of pulses generated in large-scale experiments designed for reproducing explosive magmatic eruptions, allowing us to evaluate the strengths and restrictions of using such experimental simulations

  8. Effects of maternal anxiety and depression during pregnancy in Chinese women on children's heart rate and blood pressure response to stress.

    PubMed

    Fan, F; Zou, Y; Tian, H; Zhang, Y; Zhang, J; Ma, X; Meng, Y; Yue, Y; Liu, K; Dart, A M

    2016-03-01

    Psychological disturbances, including anxiety and depression, are common during human pregnancy. Our objective was to determine whether these maternal disturbances influence cardiovascular responses of the offspring. The psychological status of 231 pregnant women was determined. Offspring (216) of these women were subsequently exposed to a video challenge stress when aged 7-9 years. Heart rate (HR) and blood pressure (BP) of the children were determined at rest, in response to video stress and during subsequent recovery. Children's resting and stress-induced increases in HR (bpm), systolic (SBP, mm Hg) and diastolic (DBP, mm Hg) BP were all greater in children whose mothers reported anxiety during pregnancy. Values (mean±s.d.) for resting HR, SBP and DBP were 75.15±5.87, 95.37±2.72 and 66.39±4.74 for children whose mothers reported no anxiety and an average of 81.62±6.71, 97.26±2.90 and 68.86±2.82 for children whose mothers reported anxiety at any level. Respective values for stress-induced increments in HR, SBP and DBP were 14.83.±2.14, 16.41±1.97 and 12.72±2.69 for children whose mothers reported no anxiety and 17.95±3.46, 18.74±2.46 and 14.86±2.02 for children whose mothers reported any level of anxiety. Effects of maternal depression were less consistent. The effects of maternal anxiety remained in multivariate analyses, which also included children's birth weight. The results indicate a long-term influence of maternal psychological status during pregnancy on the cardiovascular responses to stress among offspring. These effects may contribute to prenatal influences on subsequent health of the offspring.

  9. Proliferation rates and gene expression profiles in human lymphoblastoid cell lines from patients with depression characterized in response to antidepressant drug therapy

    PubMed Central

    Breitfeld, J; Scholl, C; Steffens, M; Brandenburg, K; Probst-Schendzielorz, K; Efimkina, O; Gurwitz, D; Ising, M; Holsboer, F; Lucae, S; Stingl, J C

    2016-01-01

    The current therapy success of depressive disorders remains in need of improvement due to low response rates and a delay in symptomatic improvement. Reliable functional biomarkers would be necessary to predict the individual treatment outcome. On the basis of the neurotrophic hypothesis of antidepressant's action, effects of antidepressant drugs on proliferation may serve as tentative individual markers for treatment efficacy. We studied individual differences in antidepressant drug effects on cell proliferation and gene expression in lymphoblastoid cell lines (LCLs) derived from patients treated for depression with documented clinical treatment outcome. Cell proliferation was characterized by EdU (5-ethynyl-2'-deoxyuridine) incorporation assays following a 3-week incubation with therapeutic concentrations of fluoxetine. Genome-wide expression profiling was conducted by microarrays, and candidate genes such as betacellulin—a gene involved in neuronal stem cell regeneration—were validated by quantitative real-time PCR. Ex vivo assessment of proliferation revealed large differences in fluoxetine-induced proliferation inhibition between donor LCLs, but no association with clinical response was observed. Genome-wide expression analyses followed by pathway and gene ontology analyses identified genes with different expression before vs after 21-day incubation with fluoxetine. Significant correlations between proliferation and gene expression of WNT2B, FZD7, TCF7L2, SULT4A1 and ABCB1 (all involved in neurogenesis or brain protection) were also found. Basal gene expression of SULT4A1 (P=0.029), and gene expression fold changes of WNT2B by ex vivo fluoxetine (P=0.025) correlated with clinical response and clinical remission, respectively. Thus, we identified potential gene expression biomarkers eventually being useful as baseline predictors or as longitudinal targets in antidepressant therapy. PMID:27845776

  10. Proliferation rates and gene expression profiles in human lymphoblastoid cell lines from patients with depression characterized in response to antidepressant drug therapy.

    PubMed

    Breitfeld, J; Scholl, C; Steffens, M; Brandenburg, K; Probst-Schendzielorz, K; Efimkina, O; Gurwitz, D; Ising, M; Holsboer, F; Lucae, S; Stingl, J C

    2016-11-15

    The current therapy success of depressive disorders remains in need of improvement due to low response rates and a delay in symptomatic improvement. Reliable functional biomarkers would be necessary to predict the individual treatment outcome. On the basis of the neurotrophic hypothesis of antidepressant's action, effects of antidepressant drugs on proliferation may serve as tentative individual markers for treatment efficacy. We studied individual differences in antidepressant drug effects on cell proliferation and gene expression in lymphoblastoid cell lines (LCLs) derived from patients treated for depression with documented clinical treatment outcome. Cell proliferation was characterized by EdU (5-ethynyl-2'-deoxyuridine) incorporation assays following a 3-week incubation with therapeutic concentrations of fluoxetine. Genome-wide expression profiling was conducted by microarrays, and candidate genes such as betacellulin-a gene involved in neuronal stem cell regeneration-were validated by quantitative real-time PCR. Ex vivo assessment of proliferation revealed large differences in fluoxetine-induced proliferation inhibition between donor LCLs, but no association with clinical response was observed. Genome-wide expression analyses followed by pathway and gene ontology analyses identified genes with different expression before vs after 21-day incubation with fluoxetine. Significant correlations between proliferation and gene expression of WNT2B, FZD7, TCF7L2, SULT4A1 and ABCB1 (all involved in neurogenesis or brain protection) were also found. Basal gene expression of SULT4A1 (P=0.029), and gene expression fold changes of WNT2B by ex vivo fluoxetine (P=0.025) correlated with clinical response and clinical remission, respectively. Thus, we identified potential gene expression biomarkers eventually being useful as baseline predictors or as longitudinal targets in antidepressant therapy.

  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. Thermodynamics and fluid dynamics of effusive subglacial eruptions

    NASA Astrophysics Data System (ADS)

    Höskuldsson, A.; Sparks, R. S. J.

    We consider the thermodynamic and fluid dynamic processes that occur during subglacial effusive eruptions. Subglacial eruptions typically generate catastrophic floods (jökulhlaups) due to melting of ice by lava and generation of a large water cavity. We consider the heat transfer from basaltic and rhyolitic lava eruptions to the ice for typical ranges of magma discharge and geometry of subglacial lavas in Iceland. Our analysis shows that the heat flux out of cooling lava is large enough to sustain vigorous natural convection in the surrounding meltwater. In subglacial eruptions the temperature difference driving convection is in the range 10-100 °C. Average temperature of the meltwater must exceed 4 °C and is usually substantially greater. We calculate melting rates of the walls of the ice cavity in the range 1-40m/day, indicating that large subglacial lakes can form rapidly as observed in the 1918 eruption of Katla and the 1996 eruption of Gjálp fissure in Vatnajökull. The volume changes associated with subglacial eruptions can cause large pressure changes in the developing ice cavity. These pressure changes can be much larger than those associated with variation of bedrock and glacier surface topography. Previous models of water-cavity stability based on hydrostatic and equilibrium conditions may not be applicable to water cavities produced rapidly in volcanic eruptions. Energy released by cooling of basaltic lava at the temperature of 1200 °C results in a volume deficiency due to volume difference between ice and water, provided that heat exchange efficiency is greater than approximately 80%. A negative pressure change inhibits escape of water, allowing large cavities to build up. Rhyolitic eruptions and basaltic eruptions, with less than approximately 80% heat exchange efficiency, cause positive pressure changes promoting continual escape of meltwater. The pressure changes in the water cavity can cause surface deformation of the ice. Laboratory

  13. 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.

  14. Winter metabolic depression does not change arterial baroreflex control of heart rate in the tegu lizard Salvator merianae.

    PubMed

    Zena, Lucas A; Dantonio, Valter; Gargaglioni, Luciane H; Andrade, Denis V; Abe, Augusto S; Bícego, Kênia C

    2016-03-01

    Baroreflex regulation of blood pressure is important for maintaining appropriate tissue perfusion. Although temperature affects heart rate (fH) reflex regulation in some reptiles and toads, no data are available on the influence of temperature-independent metabolic states on baroreflex. The South American tegu lizard Salvator merianae exhibits a clear seasonal cycle of activity decreasing fH along with winter metabolic downregulation, independent of body temperature. Through pharmacological interventions (phenylephrine and sodium nitroprusside), the baroreflex control of fH was studied at ∼ 25 °C in spring-summer- and winter-acclimated tegus. In winter lizards, resting and minimum fH were lower than in spring-summer animals (respectively, 13.3 ± 0.82 versus 10.3 ± 0.81 and 11.2 ± 0.65 versus 7.97 ± 0.88 beats min(-1)), while no acclimation differences occurred in resting blood pressure (5.14 ± 0.38 versus 5.06 ± 0.56 kPa), baroreflex gain (94.3 ± 10.7 versus 138.7 ± 30.3% kPa(-1)) or rate-pressure product (an index of myocardial activity). Vagal tone exceeded the sympathetic tone of fH, especially in the winter group. Therefore, despite the lower fH, winter acclimation does not diminish the fH baroreflex responses or rate-pressure product, possibly because of increased stroke volume that may arise because of heart hypertrophy. Independent of acclimation, fH responded more to hypotension than to hypertension. This should imply that tegus, which have no pressure separation within the single heart ventricle, must have other protection mechanisms against pulmonary hypertension or oedema, presumably through lymphatic drainage and/or vagal vasoconstriction of pulmonary artery. Such a predominant fH reflex response to hypotension, previously observed in anurans, crocodilians and mammals, may be a common feature of tetrapods.

  15. The Campi Flegrei caldera (Italy): Formation and evolution in interplay with sea-level variations since the Campanian Ignimbrite eruption at 39 ka

    NASA Astrophysics Data System (ADS)

    Steinmann, Lena; Spiess, Volkhard; Sacchi, Marco

    2016-11-01

    To date, the origin of the Campi Flegrei caldera is still under debate and may be related to (1) a single caldera collapse associated with the Neapolitan Yellow Tuff (NYT) eruption, (2) two subsequent caldera collapses associated with the NYT and the preceding Campanian Ignimbrite (CI) eruptions forming a nested-caldera complex, or (3) not related to a caldera collapse after all. Here, we study the submerged portion of the caldera, which has favored a marine depositional setting and, thus, represents an ideal location for the reconstruction of its formation history, utilizing multichannel seismic data. Volcanic deposits and edifices were seismically distinguished from sedimentary successions, and the stratigraphy could be refined and extended back to the Campanian Ignimbrite eruption at 39 ka. High-resolution multichannel reflection seismic data revealed the existence of a nested-caldera complex formed during the CI eruption at 39 ka and the more recent NYT eruption at 15 ka. A ring-fault bounding an inner caldera collapse structure was clearly imaged. It appears that this inner ring-fault was initially activated during the CI caldera collapse and later reactivated during the NYT caldera collapse with different amounts of subsidence. The NYT caldera probably formed during an asymmetrical collapse with a maximum subsidence of 75 m in the offshore portion. The vertical displacement related to the CI caldera collapse may be significantly larger. The submerged caldera depression accommodates post-eruption sediments. Within this high-resolution archive, two major unconformities developed at 8.6 ka and 5 ka, when resurgence-related uplift exceeded the rate of sea-level rise concurrent with the emersion of the La Starza terrace. A previously unknown post-collapse submarine volcanic mound located between Nisida Island and Nisida Bank probably formed between 4.8 and 3.7 ka. Also, the Penta Palummo Bank appears to be constructed of at least two monogenetic volcanic edifices

  16. Factors affecting self-eruption of displaced permanent maxillary canines.

    PubMed

    Smailienė, Dalia; Sidlauskas, Antanas; Lopatienė, Kristina; Guzevičienė, Vesta; Juodžbalys, Gintaras

    2011-01-01

    The aim of this study was to examine the possibility of the spontaneous eruption of displaced unerupted maxillary canines after the extraction of the deciduous canine and dental arch expansion and to determine the impact of initial canine position on treatment success rate. Materials and METHODS. The study sample included 50 patients (mean age, 13.5 years [SD, 2.2]) with unilaterally displaced unerupted maxillary canines. Deciduous canines were extracted, and the space for displaced canine was created at the beginning of the study. The follow-up period for the spontaneous eruption was 12 months. The initial vertical, horizontal, labio-palatal position and angle of inclination to the midline of the displaced canine were assessed on panoramic radiographs. RESULTS. Only 42% of displaced canines erupted spontaneously within one-year period (52.9% of labially displaced canines and 36.4% of palatally displaced canines). A significant difference of inclination was determined between spontaneously erupted and unerupted teeth in the labially displaced canine group (P<0.01), with no difference in the palatally displaced canine group. The receiver operating characteristic curve analysis showed that the critical angle of inclination for the spontaneous eruption of the retained canine was 20º (sensitivity 0.759; specificity 0.571; P<0.05). The majority of unerupted canines (75.9%) were inclined more than 20º. The initial height of canine was crucial for spontaneous eruption (sensitivity 0.966; specificity 0.81; P<0.001). This was true for both palatal and labial cases. CONCLUSIONS. The initial vertical position of the labially and palatally displaced canines and the inclination of the labially displaced canines were the most important predictors for spontaneous eruption of the cuspid.

  17. Rheology of the 2006 Eruption at Tungurahua Volcano, Ecuador

    NASA Astrophysics Data System (ADS)

    Hanson, J. B.; Goldstein, F.; Lavallee, Y.; Kueppers, U.; von Aulock, F. W.; Mothes, P. A.; Bustillos, J.; Douillet, G.; Hess, K.; Dingwell, D. B.

    2009-12-01

    The current eruptive activity at Tungurahua commenced in 1999 and has seen several episodes of explosive volcanism during the intervening years. Important eruptions generating pyroclastic flows occurred in July 2006, August 2006 and February 2008. The August 2006 eruption climaxed in a VEI 3 explosion with 10s of pyroclastic flows and notably terminated with the extrusion of a 3-km long lava flow. This variability of eruptive scenarios represents an excellent opportunity to study the occurrence of multiple pulses of pyroclastic activity associated with near contemporaneous extrusion of lava flow from a single, central vent. Here we present results from an extensive field campaign in August 2009 and ongoing parameterization of the rheology of the cogenetic magmas involved during this most recent eruptive cycle at Tungurahua. We observe that in the July deposits, the pyroclastic flows were rich in dense exotic lithics and contained approximately ca. 50 % lapili to bomb size juvenile pyroclasts. In contrast, the August deposits are richer in porous, juvenile material (ca. 90%) and often host pancake-shaped bread-crust bombs. Evidence of pre-eruption magma mingling textures is found occasionally within the August activity. The August a’a lava flow is characterized by dense flow-banded blocks. Magma rheology is considered a chief determinant of eruptive style. While the rheology of single-phase silicate melts is well understood, the description of magma such as that at Tungurahua (i.e., bearing 30-50 % crystals and 10-35% bubbles) is relatively unknown. During sub-Plinian-type eruptions, the transition from ductile to brittle behaviour is largely strain rate, and temperature, dependent. Using a dilatometer, we measure softening temperatures (at a heating rate of 10 °C/min) of ca. 976 °C for the dense clasts and 1060 °C for the bread-crust bombs (with 35 % pores). Complementary deformation experiments in a uniaxial press reveal a variable strain rate

  18. 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.

  19. 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.

  20. Degassing and Vesiculation during the 2011 Eruption of Axial Seamount, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Jones, M.; Soule, S. A.

    2015-12-01

    The dependency of CO2 disequilibrium in mid-ocean ridge basalts (MORB) on magma ascent and emplacement rates makes volatile analysis a valuable tool for evaluating submarine eruption dynamics. This study examines volatile content and vesicle size distributions in a suite of samples collected from the 2011 eruption of Axial Seamount. The samples exhibit a wide range of dissolved CO2 concentrations (68 - 339 ppm), low H2O concentrations (0.17 - 0.26 wt %), and consistent supersaturation relative to the expected CO2-H2O phase equilibrium in basaltic melts. The vesicularity, characteristic bubble radii, and bubble number density correlate with the dissolved volatile concentrations and indicate that bubble nucleation and growth occur within a closed system. The extent of degassing increases with distance from the eruptive vent and variations are also observed along the eruptive fissure providing a spatially resolved record of eruption dynamics. A bubble growth model is used to constrain the minimum ascent rates, eruption duration, and flow rates for the 2011 eruption. These results are compared to similar data from the global mid-ocean ridge system to evaluate differences in timescales of emplacement and ascent in MOR eruptions.

  1. Io - One of at Least Four Simultaneous Erupting Volcanic Eruptions

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This photo of an active volcanic eruption on Jupiter's satellite Io was taken 1 hour, 52 minutes after the accompanying picture, late in the evening of March 4, 1979, Pacific time. On the limb of the satellite can be seen one of at least four simultaneous volcanic eruptions -- the first such activity ever observed on another celestial body. Seen against the limb are plume-like structures rising more than 60 miles (100 kilometers) above the surface. Several eruptions have been identified with volcanic structures on the surface of Io, which have also been identified by Voyager 1's infrared instrument as being abnormally hot -- several hundred degrees warmer than surrounding terrain. The fact that several eruptions appear to be occurring at the same time suggests that Io has the most active surface in the solar system and that volcanism is going on there essentially continuously. Another characteristic of the observed volcanism is that it appears to be extremely explosive, with velocities more than 2,000 miles an hour (at least 1 kilometer per second). That is more violent than terrestrial volcanoes like Etna, Vesuvius or Krakatoa.

  2. 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.

  3. Mt. Etna Eruption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1: Vis/NIR Image CloseupFigure 2: Difference Image

    October 2002 Mt. Etna, a volcano on the island of Sicily, erupted on October 26, 2002. Preliminary analysis of data taken by the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite on October 28 shows the instrument can provide an excellent means to study the evolution and structure of the sulfur dioxide (SO2) plume emitted from volcanoes. These data also demonstrate that AIRS can be used to obtain the total mass of SO2 injected into the atmosphere during a volcanic event, information that may help us to better understand these dangerous natural occurrences in the future.

    This image was made from a sensor on the AIRS instrument that is sensitive to the visible and near-infrared portions of the spectrum. The visible/near infrared data show the smoke plume from Mt. Etna. The view is of Europe and the central Mediterranean with Italy in the center. Since the visible/near infrared sensor on AIRS is sensitive to wavelengths that are different than the human eye, vegetated regions appear red (compare the red color of Europe with the tan desert of North Africa in the lower left). Figure 1 is a closer view of Sicily and shows a long, brownish smoke plume extending across the Mediterranean to Africa. This is consistent with the enhanced feature in the difference image in Figure 2 and helps validate the information inferred from that image.

    Figure 2 clearly shows the SO2 plume. This image was created by comparing data taken at two different frequencies, or channels, and creating one image that highlights the differences between these two channels. Both channels are sensitive to water vapor, but one of the channels is also sensitive to SO2. By subtracting out the common water vapor signal in both channels, the SO2 feature remains and shows up as an enhancement in the difference image.

    The

  4. 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.

  5. Redoubt Volcano: 2009 Eruption Overview

    NASA Astrophysics Data System (ADS)

    Bull, K. F.

    2009-12-01

    Redoubt Volcano is a 3110-m glaciated stratovolcano located 170 km SW of Anchorage, Alaska, on the W side of Cook Inlet. The edifice comprises a <1500-m-thick sequence of mid-Pleistocene to recent, basaltic to dacitic pyroclastic-, block-and-ash- and lava-flow deposits built on Jurassic tonalite. Magma-ice contact features are common. A dissected earlier cone underlies the E flank of Redoubt. Alunite-bearing debris flows to the SE, E and N suggest multiple flank collapses over Redoubt's history. Most recent eruptions occurred in 1966-68, and 1989-90. In March 2009, Redoubt erupted to produce pyroclastic flows, voluminous lahars, and tephra that fell over large portions of south-central Alaska. Regional and local air traffic was significantly disrupted, Anchorage airport was closed for over 12 hours, and oil production in Cook Inlet was halted for nearly five months. Unrest began in August, 2008 with reports of H2S odor. In late September, the Alaska Volcano Observatory (AVO)’s seismic network recorded periods of volcanic tremor. Throughout the fall, AVO noted increased fumarolic emissions and accompanying ice- and snow-melt on and around the 1990 dome, and gas measurements showed elevated H2S and CO2 emissions. On January 23, seismometers recorded 48 hrs of intermittent tremor and discrete, low-frequency to hybrid events. Over the next 6 weeks, seismicity waxed and waned, an estimated 5-6 million m3 of ice were lost due to melting, volcanic gas emissions increased, and debris flows emerged repeatedly from recently formed ice holes near the 1990 dome, located on the crater’s N (“Drift”) side. On March 15, a phreatic explosion deposited non-juvenile ash from a new vent in the summit ice cap just S of the 1990 dome. Ash from the explosion rose to ~4500 m above sea level (asl). The plume was accompanied by weak seismicity. The first magmatic explosion occurred on March 22. Over the next two weeks, more than 19 explosions destroyed at least two lava domes and

  6. Postnatal Depression Prevention Through Prenatal Intervention: A Literature Review

    DTIC Science & Technology

    2006-03-17

    postpartum depression. Despite this knowledge, the prevalence rates of depression are high and prenatal depression (PND) may go unrecognized by the healthcare...depression has a prevalence rate of 20%, while postpartum depression affects 11% of previously pregnant women (Tycbey et al., 2005). One of the goals of...on prenatal care and postpartum depression, however, the issue of prenatal depression is often overlooked and the majority of the studies reviewed

  7. 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.

  8. 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.

  9. 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.

  10. Extrusion cycles during dome-building eruptions

    NASA Astrophysics Data System (ADS)

    de' Michieli Vitturi, M.; Clarke, A. B.; Neri, A.; Voight, B.

    2013-06-01

    We identify and quantify controls on the timescales and magnitudes of cyclic (periodic) volcanic eruptions using the numerical model DOMEFLOW (de' Michieli Vitturi et al., 2010) which was developed by the authors for magma systems of intermediate composition. DOMEFLOW treats the magma mixture as a liquid continuum with dispersed gas bubbles and crystals in thermodynamic equilibrium with the melt and assumes a modified Poiseuille form of the viscous term for fully developed laminar flow in a conduit of cylindrical cross-section. During ascent, magma pressure decreases and water vapor exsolves and partially degasses from the melt as the melt simultaneously crystallizes, causing changes in mixture density and viscosity. Two mechanisms previously proposed to cause periodic eruption behavior have been implemented in the model and their corresponding timescales explored. The first applies a stick-slip model in which motion of a shallow solid plug is resisted by static/dynamic friction, as described in Iverson et al. (2006). For a constant magma supply rate at depth, this mechanism yields cyclic extrusion with timescales of seconds to tens of seconds with values generally depending on assumed friction coefficients. The second mechanism does not consider friction but treats the plug as a high-viscosity Newtonian fluid. During viscous resistance, pressure beneath the degassed plug can increase sufficiently to overcome dome overburden, plug weight, and viscous forces, and ultimately drive the plug from the conduit. In this second model cycle periods are on the order of hours, and decrease with increasing magma supply rate until a threshold is reached, at which point periodicity disappears and extrusion rate becomes steady (vanishingly short periods). Magma volatile content for fixed chamber pressure has little effect on cycle timescales, but increasing volatile content increases mass flow rate and cycle magnitude as defined by the difference between maximum and minimum

  11. 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.

  12. 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

  13. 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.

  14. [Depression in the very elderly].

    PubMed

    Linden, M; Kurtz, G; Baltes, M M; Geiselmann, B; Lang, F R; Reischies, F M; Helmchen, H

    1998-01-01

    In the Berlin Aging Study (BASE) an age and gender stratified sample of 516 persons aged 70 to over 100 was assessed by means of the semi-structured GMS-A interview, the CES-D-self-rating scale and the Hamiltion-Depression-observer-rating scale. Prevalence rates were 4.8% for Major Depression, 9.1% for all DSM III-R specified depressive disorders and 26.9% of subthreshold depression was included. There was no increase in prevalence rates with age but an increase in scores on the self rating CES-D. The prevalence rates for DSM III-R specified depression in females was 10.3% and almost double that of men (5.6%). Depressed persons do not show significant cognitive impairment as measured with the MMSE in comparison to controls. As compared to the total sample higher prevalence rates of overall depression were seen in persons with multimorbidity (36.8%) and lower rates in married persons. 13.2% of the elderly talked about feeling tired with life, 7.9% had thoughts about death and 1.2% reported suicidal ideation, which was closely linked to depressive disorders. In 44% of depressed cases undertreatment was observed. Only 6% got Antidepressants but 40% benzodiazepines.

  15. Post adoption depression.

    PubMed

    Fields, Eve S; Meuchel, Jennifer M; Jaffe, Chiara J; Jha, Manish; Payne, Jennifer L

    2010-04-01

    We sought to evaluate the prevalence rate and factors associated with post adoption depression. One hundred and twelve adoptive mothers of infants under 12 months of age were recruited from local and national adoption organizations. A modified Edinburgh Postnatal Depression Scale (EPDS) and a questionnaire collecting medical and psychiatric history, perceived stress, and demographics were administered retrospectively. The rates of significant depressive symptoms (defined as EPDS >or=12) were calculated at three time points post adoption, and associations with specific clinical variables (personal or family psychiatric history, stress, and adjustment difficulty) were assessed. Eighty-six mothers were included. Rates of significant depressive symptoms (EPDS >or=12) were found in 27.9% of subjects at 0-4 weeks, 25.6% at 5-12 weeks, and 12.8% at 13-52 weeks post adoption. Significant depressive symptoms were not associated with personal or family psychiatric history but were associated with stress (p = 0.0011) and adjustment difficulties (p = 0.042) post adoption. Significant depressive symptoms were relatively common in adoptive mothers within the first year after adoption and were associated with environmental stress. Prospective studies are needed to confirm the existence of post adoption depression and the factors associated with it.

  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. 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

  18. Widespread strombolian eruptions of mid-ocean ridge basalt

    NASA Astrophysics Data System (ADS)

    Clague, David A.; Paduan, Jennifer B.; Davis, Alice S.

    2009-03-01

    Glassy lava fragments were collected in pushcores or using a small suction-sampler from over 450 sites along the Juan de Fuca Ridge, Blanco Transform Fault, Gorda Ridge, northern East Pacific Rise, southern East Pacific Rise, Fiji back-arc basin, and near-ridge seamounts in the Vance, President Jackson, Taney, and a seamount off southern California. The samples consist of angular glass fragments, limu o Pele, Pele's hair, and other fluidal fragments formed during pyroclastic eruptions. Since many of the sites are deeper than the critical point of seawater, fragmentation cannot be hydrovolcanic and caused by expansion of seawater to steam. The glass fragments have a wide range of MORB compositions, ranging from fractionated to primitive and from depleted to enriched. Enriched magmas, which have higher volatile contents, may form more abundant pyroclasts than depleted magmas. Eruptions with high effusion rates produce sheet flows and abundant pyroclasts whereas those with low effusion rates produce pillow ridges and few pyroclasts. This relation suggests that high effusion and conduit rise rates are coupled to high magmatic gas contents. The eruptions are mainly effusive with a minor strombolian bubble burst component. We propose that the gas phase is an added component of variable amounts of magmatic foam from the top of the magma reservoir. As the mixture of resident magma and foam rises in the conduit, the larger bubbles in the foam rise more quickly and sweep up the smaller bubbles nucleating and growing from the resident magma. On eruption, the process of bubble coalescence is more complete for the slower rising, gas-poor lavas that erupt as pillow lavas whereas the limu o Pele associated with sheet flow eruptions commonly contain several percent vesicles that avoided coalescence during ascent. The spatter erupted at the vent is quench granulated in seawater above the vent, reducing the pyroclast grainsize. The granulated spatter and limu o Pele fragments are

  19. 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…

  20. 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

  1. May 2011 eruption of Telica Volcano, Nicaragua: Multidisciplinary observations

    NASA Astrophysics Data System (ADS)

    Witter, M. R.; Geirsson, H.; La Femina, P. C.; Roman, D. C.; Rodgers, M.; Muñoz, A.; Morales, A.; Tenorio, V.; Chavarria, D.; Feineman, M. D.; Furman, T.; Longley, A.

    2011-12-01

    Telica volcano, an andesitic stratovolcano in north-western Nicaragua, erupted in May 2011. The eruption, produced ash but no lava and required the evacuation of over 500 people; no injuries were reported. We present the first detailed report of the eruption, using information from the TElica Seismic ANd Deformation (TESAND) network, that provides real-time data, along with visual observations, ash leachate analysis, and fumarole temperature measurements. Telica is located in the Maribios mountain range. It is one of the most active volcanoes in Nicaragua and has frequent small explosions and rare large (VEI 4) eruptions, with the most recent sizable eruptions (VEI 2) occurring in 1946 and 1999. The 2011 eruption is the most explosive since 1999. The eruption consisted of a series of ash explosions, with the first observations from May 8, 2011 when local residents reported ash fall NE of the active crater. Popping sounds could be heard coming from the crater on May 10. On May 13, the activity intensified and continued with some explosions every day for about 2 weeks. The well-defined plumes originated from the northern part of the crater. Ash fall was reported 4 km north of the active crater on May 14. The largest explosion at 2:54 pm (local time) on May 21 threw rocks from the crater and generated a column 2 km in height. Fresh ash samples were collected on May 16, 18, and 21 and preliminary inspection shows that the majority of the material is fragmented rock and crystalline material, i.e. not juvenile. Ash leachates (ash:water = 1:25) contain a few ppb As, Se, and Cd; tens of ppb Co and Ni; and up to a few hundred ppb Cu and Zn. Telica typically has hundreds of small seismic events every day, even when the volcano is not erupting. The TESAND network detected an increase in the rate and magnitude of seismic activity, with a maximum magnitude of 3.3. Elevated fumarole temperatures at locations near the active vent were also observed throughout the May 2011

  2. Eruptive history of Sundoro volcano, Central Java, Indonesia since 34 ka

    NASA Astrophysics Data System (ADS)

    Prambada, Oktory; Arakawa, Yoji; Ikehata, Kei; Furukawa, Ryuta; Takada, Akira; Wibowo, Haryo Edi; Nakagawa, Mitsuhiro; Kartadinata, M. Nugraha

    2016-11-01

    Reconstruction of the eruptive history of Sundoro volcano is needed to forecast the probability of future eruptions and eruptive volumes. Sundoro volcano is located in Central Java (Indonesia), 65 km northwest of Yogyakarta, and in one of the most densely populated areas of Indonesia. On the basis of stratigraphy, radiocarbon dating, petrography, and whole-rock geochemistry, we recognize the following 12 eruptive groups: (1) Ngadirejo, (2) Bansari, (3) Arum, (4) Kembang, (5) Kekep, (6) Garung, (7) Kertek, (8) Watu, (9) Liyangan, (10) Kledung, (11) Summit, and (12) Sibajak. The Ngadirejo (34 ka BP) to Kledung (1 ka) eruptive groups are inferred to have been the stratovolcano building phase. Based on compositions of deposits, one or more magma reservoirs of intermediate chemical composition are inferred to have existed below the volcano during the periods of time represented by the eruptive groups. SiO2 of juvenile eruptive products ranges from 50 to 63 wt%, and K2O contents range from high K to medium K. The chemical composition and phenocryst content of eruptive products change with time. The lower SiO2 products contain mainly plagioclase, clinopyroxene, and olivine, whereas the more evolved rocks contain plagioclase, clinopyroxene, orthopyroxene, and rare hornblende and olivine. Our work has defined Sundoro's eruptive history for the period 1-34 ka, and this history helps us to forecast future activity. We estimated that the total amount of magma discharged since 34 ka is approximately 4.4 km3. The average eruption rate over this group ranges from 0.14 to 0.17 km3/kyr. The eruption rate and the frequency of individual eruptions indicate that the volcano has been very active since 34 ka, and this activity in combination with our petrological data suggest the presence of one or more magma reservoirs that have been repeatedly filled and then discharged as eruptions have taken place. Our data further suggest that the volume of the crustal reservoir system has

  3. 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

  4. 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

  5. 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 ...

  6. Depression Treatment

    MedlinePlus

    ... 3286 After hours (404) 639-2888 Contact Media Depression Treatment Recommend on Facebook Tweet Share Compartir On ... How Do I Know if I Am Experiencing Depression? The following questions may help you determine if ...

  7. Depression Screening

    MedlinePlus

    ... Centers Diseases + Condition Centers Mental Health Medical Library Depression Screening (PHQ-9) - Instructions The following questions are ... this tool, there is also text-only version . Depression Screening - Manual Instructions The following questions are a ...

  8. 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 ...

  9. Accurate detection of coronary artery disease by integrated analysis of the ST-segment depression/heart rate patterns during the exercise and recovery phases of the exercise electrocardiography test.

    PubMed

    Lehtinen, R; Sievänen, H; Viik, J; Turjanmaa, V; Niemelä, K; Malmivuo, J

    1996-11-01

    In this comparative cross-sectional study, we evaluated whether a novel computerized diagnostic variable, ST-segment depression/heart rate ST/HR analysis during both the exercise and postexercise recovery phases of the exercise electrocardiography (ECG) test, can detect coronary artery disease more accurately than methods using either exercise or recovery phase alone. The study population comprised 347 clinical patients referred for a routine bicycle exercise ECG test at Tampere University Hospital, Finland. Of these, 127 had angiographically proven coronary artery disease, whereas 13 had no coronary artery disease according to angiography, 18 had no perfusion defect according to technetium-99m sestamibi single-photon emission computed tomography, and 189 were clinically normal with respect to cardiac diseases. For each patient, the maximum values of the ST/HR hysteresis, ST/HR index, end-exercise ST depression, and recovery ST depression were determined from the Mason-Likar modification of the standard 12-lead exercise electrocardiogram [aVL, aVR, and V1 excluded]. The diagnostic performance of these continuous diagnostic variables was compared by means of receiver-operating characteristic analysis. The area under the receiver-operating characteristic curve of the ST/HR hysteresis was 89%, which was significantly larger than that of the end-exercise ST depression (76%, p < or = 0.0001), recovery ST depression (84%, p = 0.0063), or ST/HR index (83%, p = 0.0023), indicating superior diagnostic performance of the ST/HR hysteresis independent of the partition value selection. In conclusion, computerized analysis of the HR-adjusted ST depression pattern during the exercise phase, integrated with the HR-adjusted ST depression pattern during the recovery phase after exercise, can significantly improve the diagnostic performance and clinical utility of the exercise ECG test for the detection of coronary artery disease.

  10. [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.

  11. Understanding Depression

    PubMed Central

    McNair, F. E.

    1981-01-01

    To understand the effects of depression on a patient's life, the physician must be aware how depression manifests itself. Somatic tension, strategies to relieve discomfort and social withdrawal must be recognized as symptoms of depression. An awareness of life situations which can give rise to these symptoms, as well as the effect of the physician's own reactions to the patient's depression, are helpful. PMID:21289767

  12. When Magma Might but Doesn't Erupt

    NASA Astrophysics Data System (ADS)

    Newhall, C.

    2008-12-01

    whammy. Magma can also enter relatively deformable structures, e.g., rift zones where it can move laterally more easily than it can ascend, or be slowed by layered soft and hard rock (Gudmundsson and Brenner, GRL 2004), increasing the chances of (a) and (b). Opportunities abound for ascending magma to stall; indeed, judging from the number of earthquake swarms and other potential indicators of magma ascent vs actual eruption, the majority of intrusions stall without erupting. Some patterns of unrest suggest that rising magma may abort before reaching the surface but these hints are non-unique. Low initial gas contents and slow rates of ascent increase chances of failure. Nishimura (GRL 2006) inferred that deformation will be constant (rather than accelerate) if magma nearing the surface has already been degassing. The same may hold for seismicity that's directly related to dike intrusion. Interpretation of degassing is tricky. Strong and constant or slowing gas emission that accompanies constant deformation increases the chance that degassing will freeze the magma before it can erupt. In contrast, strong and accelerating degassing that accompanies accelerating deformation may indicate a runaway approach to eruption, as may unusually low gas emission during accelerating deformation if the conduit is still plugged. Accelerated degassing can also occur when a dry chimney develops through water-saturated country rock, with or without deformation. Low (acid) gas emission by itself tells us little, as it can be scrubbed into groundwater. Those interpreting unrest need to consider all possible outcomes, including both total failure to erupt and the possibility that what looks like a failed eruption today may be on hold and may yet occur.

  13. 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

  14. Kizimen Volcano, Kamchatka, Russia: 2010-2012 Eruptive Activity

    NASA Astrophysics Data System (ADS)

    Gordeev, E.; Droznin, V.; Malik, N.; Muravyev, Y.

    2012-12-01

    New eruptive activity at Kizimen Volcano began in October 2010 after 1.5 years of seismic build up. Two vents located at the summit of the volcano had been producing occasional steam-and-gas emissions with traces of ash until early December. Kizimen is located at a junction between Shapensky graben in the Central Kamchatka Depression and a horst of Tumrok Ridge. Kizimen is a 2376 m a.s.l. complex stratovolcano. The only single eruption reported in historic time occurred from December 1928 to January 1929. Little is known about the volcano; explosive activity was preceded by strong local earthquakes, and ashfalls were reported in neighboring settlements. During the period between eruptions the volcano was producing constant fumarolic activity, reported since 1825. During the cause of the current (2010-2012) eruption, the volcano produced several eruptive phases: moderate explosive activity was observed from December 10, 2010 to late February 2011 (ashfalls and descend of pyroclastic flows resulted in a large lahar traveling along the valley of the Poperechny Creek on December 13, 2010); from late February to mid-December the volcano produced an explosive-effusive phase (the lava flow descended eastern flank, while explosive activity has decreased), which resulted in strong explosions on December 14, 2011 accompanied by scores of pyroclastic flows of various thickness to the NE foot on the volcano. Since then, a constant growth of the large lava flow has been accompanied by strong steam-and-gas emissions from the summit crater. The erupted materials are tephra and deposits of pyroclastic and lava flows consisted of high-aluminous andesites and dacites of potassium-sodium series: SiO2 content varied from 61% in December 2010 to 65-68% in January-February 2011, and up to 62% in December 2011. Ashfalls area exceeded 100 km2 (the weight of erupted tephra > 107 tons), while the total area of pyroclastic flows was estimated to be 15.5 km2 (V= 0.16 km3). Until late May 2012

  15. 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.

  16. Morphology, temperature, and eruption dynamics at Pele

    NASA Astrophysics Data System (ADS)

    Howell, Robert R.; Lopes, Rosaly M. C.

    2011-06-01

    ., Milazzo, M., Radebaugh, J., Davies, A.G., Mitchell, K.L. [2007]. Icarus 192, 491-502). When applied to the I32 observations we obtain a fire-fountain mass eruption rate of 5.1 × 10 5 kg s -1 for the main vent area and 1.4 × 10 4 kg s -1 for each of two smaller vent regions to the west. These fire-fountain rates suggest a solution to the puzzling lack of extensive lava flows in the Pele region. Much of the erupted lava may be ejected at high speed into the fire-fountains and plumes, creating dispersed pyroclastic deposits rather than flows. We compare gas and silicate mass eruption rates and discuss briefly the dynamics of this ejection model and the observational evidence.

  17. 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.

  18. 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

  19. 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

  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. Numerical models of volcanic eruption plumes: inter-comparison and sensitivity

    NASA Astrophysics Data System (ADS)

    Costa, Antonio; Suzuki, Yujiro; Folch, Arnau; Cioni, Raffaello

    2016-10-01

    The accurate description of the dynamics of convective plumes developed during explosive volcanic eruptions represents one of the most crucial and intriguing challenges in volcanology. Eruptive plume dynamics are significantly affected by complex interactions with the surrounding atmosphere, in the case of both strong eruption columns, rising vertically above the tropopause, and weak volcanic plumes, developing within the troposphere and often following bended trajectories. The understanding of eruptive plume dynamics is pivotal for estimating mass flow rates of volcanic sources, a crucial aspect for tephra dispersion models used to assess aviation safety and tephra fallout hazard. For these reasons, several eruption column models have been developed in the past decades, including the more recent sophisticated computational fluid dynamic models.

  2. The 1998 eruption of Axial Seamount: New insights on submarine lava flow emplacement from high-resolution mapping

    NASA Astrophysics Data System (ADS)

    Chadwick, W. W.; Clague, D. A.; Embley, R. W.; Perfit, M. R.; Butterfield, D. A.; Caress, D. W.; Paduan, J. B.; Martin, J. F.; Sasnett, P.; Merle, S. G.; Bobbitt, A. M.

    2013-10-01

    Axial Seamount, an active submarine volcano on the Juan de Fuca Ridge at 46°N, 130°W, erupted in January 1998 along 11 km of its upper south rift zone. We use ship-based multibeam sonar, high-resolution (1 m) bathymetry, sidescan sonar imagery, and submersible dive observations to map four separate 1998 lava flows that were fed from 11 eruptive fissures. These new mapping results give an eruption volume of 31 × 106 m3, 70% of which was in the northern-most flow, 23% in the southern-most flow, and 7% in two smaller flows in between. We introduce the concept of map-scale submarine lava flow morphology (observed at a scale of hundreds of meters, as revealed by the high-resolution bathymetry), and an interpretive model in which two map-scale morphologies are produced by high effusion-rate eruptions: "inflated lobate flows" are formed near eruptive vents, and where they drain downslope more than 0.5-1.0 km, they transition to "inflated pillow flows." These two morphologies are observed on the 1998 lava flows at Axial. A third map-scale flow morphology that was not produced during this eruption, "pillow mounds," is formed by low effusion-rate eruptions in which pillow lava piles up directly over the eruptive vents. Axial Seamount erupted again in April 2011 and there are remarkable similarities between the 1998 and 2011 eruptions, particularly the locations of eruptive vents and lava flow morphologies. Because the 2011 eruption reused most of the same eruptive fissures, 58% of the area of the 1998 lava flows is now covered by 2011 lava.

  3. 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

  4. Shallow conduit processes during the 1158 AD explosive eruption of Hekla volcano, Iceland

    NASA Astrophysics Data System (ADS)

    Janebo, Maria; Houghton, Bruce; Thordarson, Thor; Larsen, Gudrun

    2015-04-01

    collapse histories for melt in the shallow portions of the conduit and the development of textural heterogeneity, leading to simultaneous fragmentation of melt of contrasting conduit residence time and hence maturity. We infer that the grey pumice reflects those pockets of magma that had slowed or stalled in the shallow conduit permitting some of the small-to-moderate-sized bubbles to undergo enhanced coalescence and limited development of vesicle pathways and open-system degassing. In this regard, the 1158 eruption contrasts with the relative homogeneity of the melt phase involved in the more powerful earlier Plinian silicic eruptions of Hekla, for which we can infer a more simple conduit history accompanying higher average ascent rates.

  5. A population of eruptive variable protostars in VVV

    NASA Astrophysics Data System (ADS)

    Contreras Peña, C.; Lucas, P. W.; Minniti, D.; Kurtev, R.; Stimson, W.; Navarro Molina, C.; Borissova, J.; Kumar, M. S. N.; Thompson, M. A.; Gledhill, T.; Terzi, R.; Froebrich, D.; Caratti o Garatti, A.

    2017-03-01

    We present the discovery of 816 high-amplitude infrared variable stars (ΔKs > 1 mag) in 119 deg2 of the Galactic mid-plane covered by the VISTA Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50 per cent are young stellar objects (YSOs). This provides further evidence that YSOs are the commonest high-amplitude infrared variable stars in the Galactic plane. In the 2010-2014 time series of likely YSOs, we find that the amplitude of variability increases towards younger evolutionary classes (class I and flat-spectrum sources) except on short time-scales (<25 d) where this trend is reversed. Dividing the likely YSOs by light-curve morphology, we find 106 with eruptive light curves, 45 dippers, 39 faders, 24 eclipsing binaries, 65 long-term periodic variables (P > 100 d) and 162 short-term variables. Eruptive YSOs and faders tend to have the highest amplitudes and eruptive systems have the reddest spectral energy distribution (SEDs). Follow-up spectroscopy in a companion paper verifies high accretion rates in the eruptive systems. Variable extinction is disfavoured by the two epochs of colour data. These discoveries increase the number of eruptive variable YSOs by a factor of at least 5, most being at earlier stages of evolution than the known FUor and EXor types. We find that eruptive variability is at least an order of magnitude more common in class I YSOs than class II YSOs. Typical outburst durations are 1-4 yr, between those of EXors and FUors. They occur in 3-6 per cent of class I YSOs over a 4 yr time span.

  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. Volcanic eruptions and solar activity

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  8. 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.

  9. 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.

  10. Dynamics of Volcanic Jets from Short-Duration Eruptions: Mixing and Rise

    NASA Astrophysics Data System (ADS)

    Chojnicki, K. N.; Gisler, G. R.; Ogden, D.

    2014-12-01

    Mixing controls volcanic plume behavior. Our understanding of mixing therefore places a critical limit on our capacity to manage volcanic plume hazards. Researchers have investigated mixing for two situations: volcanic plumes with rise times that are long or short relative to the eruption duration. The plumes generated in these two situations are then modeled as thermals or maintained plumes, respectively. The case in the middle, when plume rise times are comparable to the eruption durations, is not often considered. This third class is appropriate to discrete eruptions, such as Strombolian- or Vulcanian-style eruptions, which last a few seconds or tens of seconds and generate relatively small plumes. Here we use numerical experiments to show that mixing occurs differently in this third eruption class because of dynamic features that are distinct from the long- and instantaneous-duration end members. In this presentation we focus on the effect of eruption duration on mixing in the inertia-driven or jet-like phase of ascending volcanic plumes. Our simulation results reveal that air entrainment rates increase after the eruption ends, resulting in enhanced overall mixing in jets from shorter-duration eruptions. Models developed for the other two mixing situations do not predict these results. New models are required for volcanic plumes with rise times comparable to their durations in order to reliably estimate their behavior for hazard management purposes.

  11. Seafloor deformation and forecasts of the April 2011 eruption at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Chadwick, William W.; Nooner, Scott L.; Butterfield, David A.; Lilley, Marvin D.

    2012-07-01

    Axial Seamount is an active submarine volcano located at the intersection between the Cobb hotspot and the Juan de Fuca spreading centre in the northeast Pacific Ocean. The volcano has been closely monitored since it erupted in 1998 (refs , ). Since then, Axial Seamount seemed to exhibit a similar inflation-deflation cycle to basaltic volcanoes on land and, on that basis, was expected to erupt again sometime before 2014 or 2020 (refs , ). In April 2011 Axial Seamount erupted. Here we report continuous measurements of ocean bottom pressure that document the deflation-inflation cycle of Axial Seamount between 1998 and 2011. We find that the volcano inflation rate, caused by the intrusion of magma, gradually increased in the months leading up to the 2011 eruption. Sudden uplift occurred 40-55min before the eruption onset, which we interpret as a precursor event. Based on our measurements of ground deformation through the entire eruption cycle at Axial Seamount, we suggest that another eruption could occur as early as 2018. We propose that the long-term eruptive cycle of Axial Seamount could be more predictable compared with its subaerial counterparts because the volcano receives a relatively steady supply of magma through the Cobb hotspot and because it is located on thin oceanic crust at a spreading plate boundary.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. RECOVERY FROM GIANT ERUPTIONS IN VERY MASSIVE STARS

    SciTech Connect

    Kashi, Amit; Davidson, Kris; Humphreys, Roberta M.

    2016-01-20

    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{sub ⊙} and 120 M{sub ⊙}, 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{sub ⊙} 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{sup −1} wind with a mass loss rate that begins around 0.1 M{sub ⊙} yr{sup −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{sub ⊙} 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.

  17. 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.

  18. Speleothems as sensitive recorders of volcanic eruptions - the Bronze Age Minoan eruption recorded in a stalagmite from Turkey

    NASA Astrophysics Data System (ADS)

    Badertscher, S.; Borsato, A.; Frisia, S.; Cheng, H.; Edwards, R. L.; Tüysüz, O.; Fleitmann, D.

    2014-04-01

    Mounting evidence exists that variations in sulphur content in stalagmites are closely linked to changes in volcanic or anthropogenic atmospheric sulphur. The strong dependency of sulphur on soil pH and ecosystem storage, however, can result in a delay of several years to decades in the registration of volcanic eruptions and anthropogenic emissions by stalagmites. Here we present synchrotron-radiation based trace element analysis performed on a precisely-dated section of a stalagmite from Sofular Cave in Northern Turkey. As this section covers the time interval of the intensively studied Minoan volcanic eruption between 1600 and 1650 BC, we can test whether this vigorous eruption can be traced in a stalagmite. Of all measured trace elements, only bromine shows a clear short-lived peak at 1621±25 BC, whereas sulphur and molybdenum show peaks later at 1617±25 and 1589±25 respectively. We suggest that all trace element peaks are related to the Minoan eruption, whereas the observed phasing of bromine, molybdenum and sulphur is related to differences in their retention rates in the soil above Sofular Cave. For the first time, we can show that bromine appears to be an ideal volcanic tracer in stalagmites, as it is a prominent volatile component in volcanic eruptions, can be easily leached in soils and rapidly transferred from the atmosphere through the soil and bedrock into the cave and stalagmite respectively. Highly resolved oxygen and carbon isotope profiles indicate that the Minoan eruption had no detectable climatic and environmental impact in Northern Turkey.

  19. Altered rate-dependent depression of the spinal H-reflex as an indicator of spinal disinhibition in models of neuropathic pain.

    PubMed

    Lee-Kubli, Corinne A G; Calcutt, Nigel A

    2014-02-01

    The unpredictable efficacy of current therapies for neuropathic pain may reflect diverse etiological mechanisms operating between, and within, diseases. As descriptions of pain rarely establish specific mechanisms, a tool that can identify underlying causes of neuropathic pain would be useful in developing patient-specific treatments. Rate-dependent depression (RDD), a measure of the change in amplitude of the Hoffman reflex over consecutive stimulations, is attenuated in diabetic rats that also exhibit impaired spinal γ-aminobutyric acid (GABA)A receptor function, reduced spinal potassium chloride co-transporter (KCC2) expression, and indices of painful neuropathy. To investigate whether loss of RDD is a reliable indicator of the contribution of spinal GABAergic dysfunction to neuropathic pain, we assessed RDD, tactile allodynia, and formalin-evoked hyperalgesia in 3 models: rats treated acutely with brain-derived neurotrophic factor (BDNF), diabetic rats treated with the BDNF-sequestering molecule tyrosine receptor kinase B/Fc (TrkB/Fc), and rats with paclitaxel-induced neuropathy. Delivery of BDNF to the spinal cord of normal rats produced RDD deficits and features of painful neuropathy associated with disrupted GABAA receptor-mediated inhibitory function and reduced dorsal spinal KCC2 expression. Treating diabetic rats with TrkB/Fc restored RDD and alleviated indices of painful neuropathy. In paclitaxel-treated rats, RDD was not impaired and behavioral indices of neuropathic pain were not associated with spinal GABAergic dysfunction or reduced dorsal spinal KCC2 expression. Our data reveal BDNF as part of the mechanism underlying spinal cord disinhibition caused by altered GABAA receptor function in diabetic rats and suggest that RDD deficits may be a useful indicator of neuropathic pain states associated with spinal disinhibition, thereby revealing specific therapeutic targets.

  20. Filament Eruption without Coronal Mass Ejection

    NASA Technical Reports Server (NTRS)

    Choudhary, Debi Prasad; Moore, Ronald L.

    2003-01-01

    We report characteristics of quiescent filament eruptions that were not associated with coronal mass ejections (CMEs). We examined 12 quiescent filament eruptions, each of which was located far from disk center (20.7 R(sub sun)) in diffuse remnant magnetic fields of decayed active regions, was well observed in full-disk movies in Ha and Fe XI, and had good coronagraph coverage. Of the 12 events, 9 were associated with CMEs and 3 were not. Even though the two kinds of eruption were indistinguishable in their magnetic setting and in the eruptive motion of the filament in the Ha movies, each of the CME-producing eruptions produced a two-ribbon flare in Ha and a coronal arcade and/or two-ribbon flare in Fe XII, and each of the non-CME-producing eruptions did not. From this result, and the appearance of the eruptive motion in the Fe XII movies, we conclude that the non-CME-associated filament eruptions are confined eruptions like the confined filament eruptions in active regions.

  1. Observed Aspects of Reconnection in Solar Eruptions

    NASA Astrophysics Data System (ADS)

    Moore, Ronald L.; Sterling, Alphonse C.; Gary, G. Allen; Cirtain, Jonathan W.; Falconer, David A.

    2011-10-01

    The observed magnetic field configuration and signatures of reconnection in the large solar magnetic eruptions that make major flares and coronal mass ejections and in the much smaller magnetic eruptions that make X-ray jets are illustrated with cartoons and representative observed eruptions. The main reconnection signatures considered are the imaged bright emission from the heated plasma on reconnected field lines. In any of these eruptions, large or small, the magnetic field that drives the eruption and/or that drives the buildup to the eruption is initially a closed bipolar arcade. From the form and configuration of the magnetic field in and around the driving arcade and from the development of the reconnection signatures in coordination with the eruption, we infer that (1) at the onset of reconnection the reconnection current sheet is small compared to the driving arcade, and (2) the current sheet can grow to the size of the driving arcade only after reconnection starts and the unleashed erupting field dynamically forces the current sheet to grow much larger, building it up faster than the reconnection can tear it down. We conjecture that the fundamental reason the quasi-static pre-eruption field is prohibited from having a large current sheet is that the magnetic pressure is much greater than the plasma pressure in the chromosphere and low corona in eruptive solar magnetic fields.

  2. Application of computer-assisted mapping to volcanic hazard evaluation of surge eruptions: Vulcano, lipari, and vesuvius

    NASA Astrophysics Data System (ADS)

    Sheridan, Michael F.; Malin, Michael C.

    1983-09-01

    A previously developed computer-assisted model has been applied to several pyroclastic-surge eruptions at three active volcanoes in Italy. Model hazard maps created for various vent locations, eruption types, and mass production rates reasonably reproduced pyroclastic-surge deposits from several recent eruptions on Vulcano, Lipari, and Vesuvius. Small-scale phreatic eruptions on the island of Vulcano (e.g. the 1727 explosion of Forgia Vecchia) pose a limited but serious threat to the village of Porto. The most dangerous zone affected by this type of eruption follows a NNW fissure system between Fossa and Vulcanello. Moderate-sized eruptions on Vulcano, such as those associated with the present Fossa Crater are a much more serious threat to Porto as well as the entire area within the caldera surrounding the cone. The less frequent surge eruptions on Lipari have been even more violent. The extreme mobility of surges like those produced from Monte Guardia (approx. 20,000 y.b.p.) and Monte Pilato would not only threaten the entire island of Lipari, but also the northern part of neighboring Vulcano. Eruptions at Vesuvius with energy and efficiency similar to that of the May 18, 1980 blast of Mount St. Helens would be still more destructive because of the great initial elevation of the summit vent. In addition, surge eruptions at Vesuvius are generally part of more complex eruption cycles that involve several other types of volcanic phenomena including Plinian fall and pyroclastic flows.

  3. 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

  4. 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

  5. Volcanic hazards from Bezymianny- and Bandai-type eruptions

    NASA Astrophysics Data System (ADS)

    Siebert, Lee; Glicken, Harry; Ui, Tadahide

    1987-02-01

    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

  6. 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

  7. 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

  8. Determining pre- and syn-eruptive timescales by diffusion methods: case studies from the Oruanui super-eruption

    NASA Astrophysics Data System (ADS)

    Morgan, D. J.; Allan, A. S.; Charlier, B. L.; Wilson, C. J.

    2012-12-01

    Diffusion methods permit investigation of timescales of short-lived processes occurring in magmatic systems before, and in some cases during, eruption. We here present three case studies from the 25.4 ka Oruanui super-eruption looking at diffusion in a variety of minerals that reflects a spectrum of timescales. At one end of the spectrum, the diffusion of Li is exceedingly rapid. Diffusion distances of >100 microns in quartz and plagioclase can be attained in minutes at magmatic conditions. Strong diffusion appears to be induced in the very latest stages of magmatic ascent across most quartz and plagioclase crystals and is interpreted to be due to changes in the melt structure and fluid-melt equilibrium during decompression. With corrections for adiabatic expansion and post-eruptive cooling, the magma ascent rate from depths corresponding to the critical pressure is constrained to be up to 21 m/s. Determining timescales here requires corrections of raw data for local anorthite contents, although Li diffusion itself appears to be largely independent of composition. Fe-Ti oxides can retain significant zonation of Fe and Ti abundance for only a matter of days at magmatic conditions, making them ideal for thermometry to establish pre-eruptive conditions. However, observation of zonation in magnetite grains can be used to infer timescales of processes occurring over days before eruption. Magnetites from the phase 7 Oruanui eruption deposits show zoning, reflecting events which occurred in the hours before quenching of the host pumice. In combination with field and textural evidence, we interpret these events to result from syn-eruptive infiltration of hot mafic magma into Oruanui rhyolite. Diffusion in this scenario is straightforward to model in one dimension but requires consideration of ambient fO2. Structural ions in silicate minerals typically diffuse much more slowly, and so yield information on long-lived and persistent processes. Fe-Mg interdiffusion in

  9. 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

  10. 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…

  11. The Latest on Volcanic Eruptions and Climate

    NASA Astrophysics Data System (ADS)

    Robock, Alan

    2013-08-01

    What was the largest volcanic eruption on Earth since the historic Mount Pinatubo eruption on 15 June 1991? Was the Toba super­eruption 74,000 years ago—the largest in the past 100,000 years—responsible for a human genetic bottleneck or a 1000-year-long glacial advance? What role did small volcanic eruptions play in the reduced global warming of the past decade? What caused the Little Ice Age? Was the April 2010 Eyjafjallajökull eruption in Iceland important for climate change? What do volcanic eruptions teach us about new ideas on geoengineering and nuclear winter? These are some of the questions that have been answered since the review article by Robock [2000]. Reviews by Forster et al. [2007] and Timmreck [2012] go into some of these topics in much greater detail.

  12. 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.

  13. 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).

  14. 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.

  15. Tremor Signals and Their Eruptive Event Characteristics: Case Study Popocatepetl Volcano (Mexico)

    NASA Astrophysics Data System (ADS)

    Arciniega, A.; Delgado, H.; Roberge, J.; Corona, P.; Hernandez, E.

    2006-12-01

    Seismic activity at Popocatepetl Volcano is characterized by a variety of signals in a wider frequency band (0.06s 30s), associated with its eruptive behavior. Since Popocatepetl reawakened in 1994 volcanic eruptive behavior has consisted of construction and destruction dome phases, strong volcanic degassing, and ash emissions ranged from small short-lived plumes rising a few hundred meters above the crater rim, to large plumes reaching 15 km above the crater with powerful ejection of ballistic projectiles associated with the destruction of lava domes. These eruptive events have been accompanied by persistent or spasmodic tremor signals before, during or after the eruption. Persistent tremor was first observed 22 hrs after the onset of explosions which marked the reawakening of Popocatepetl volcano on December 21, 1994, this kind of sustained tremor also occurred during lava effusion episodes. Tremor signals present a wide range of amplitudes and dominant periods in the range from 0.2-20~s, their duration may last from few minutes to days. We analyzed broadband records of tremor from stations of permanent and temporal networks associated with eruptive episodes occurred in May to July, 1997, September to December, 1998, and February to May and December, 2000. The tremor characteristics of these particular events are comparing with tremor episodes that are not related to eruption events and with sustained low-amplitude tremor observed to persist for hours. We correlate temporal, frequency and waveform characteristics of different tremor episodes with punctual measurements of sulfur dioxide emission rates, standard deviation and geochemistry analysis of ashes of the corresponding eruptive event. The results of correlation analyses indicate that tremor characteristics and properties of its associated eruptive event reflect conditions in the volcanic eruptive behavior and may help in monitoring eruptive dynamics.

  16. 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

  17. Flux Cancellation Leading to CME Filament Eruptions

    NASA Technical Reports Server (NTRS)

    Popescu, Roxana M.; Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    Solar filaments are strands of relatively cool, dense plasma magnetically suspended in the lower density hotter solar corona. They trace magnetic polarity inversion lines (PILs) in the photosphere below, and are supported against gravity at heights of up to approx.100 Mm above the chromosphere by the magnetic field in and around them. This field erupts when it is rendered unstable, often by magnetic flux cancellation or emergence at or near the PIL. We have studied the evolution of photospheric magnetic flux leading to ten observed filament eruptions. Specifically, we look for gradual magnetic changes in the neighborhood of the PIL prior to and during eruption. We use Extreme Ultraviolet (EUV) images from the Atmospheric Imaging Assembly (AIA), and magnetograms from the Helioseismic and Magnetic Imager (HMI), both on board the Solar Dynamics Observatory (SDO), to study filament eruptions and their photospheric magnetic fields. We examine whether flux cancellation or/and emergence leads to filament eruptions. We find that continuous flux cancellation was present at the PIL for many hours prior to each eruption. We present two CME-producing eruptions in detail and find the following: (a) the pre-eruption filament-holding core field is highly sheared and appears in the shape of a sigmoid above the PIL; (b) at the start of the eruption the opposite arms of the sigmoid reconnect in the middle above the site of (tether-cutting) flux cancellation at the PIL; (c) the filaments first show a slow-rise, followed by a fast-rise as they erupt. We conclude that these two filament eruptions result from flux cancellation in the middle of the sheared field, and thereafter evolve in agreement with the standard model for a CME/flare filament eruption from a closed bipolar magnetic field [flux cancellation (van Ballegooijen and Martens 1989 and Moore and Roumelrotis 1992) and runaway tether-cutting (Moore et. al 2001)].

  18. 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.

  19. 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.

  20. 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.