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Sample records for depressed eruption rate

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

    SciTech Connect

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

    1990-03-01

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

  2. The Effects of Preeruptive Magma Viscosity on Eruption Styles and Magma Eruption Rates

    NASA Astrophysics Data System (ADS)

    Tomiya, A.; Koyaguchi, T.; Kozono, T.; Takeuchi, S.

    2014-12-01

    We have collected data on magma eruption rate, which is one of the most fundamental parameters for a volcanic eruption. There are several compilations on eruption rates, for example, for Plinian eruptions (Carey and Sigurdsson, 1989), basaltic eruptions (Wadge, 1981), lava dome eruptions (Newhall and Melson, 1983), and all combined (Tomiya and Koyaguchi, 1998; Pyle, 2000). However, they did not quantitatively discuss the effects of magma viscosity, which must control eruption rates. Here, we discuss the effects of magma viscosity on eruption rates, by using 'preeruptive magma viscosities', which are important measures of magma eruptibility (Takeuchi, 2011). Preeruptive magma viscosity is the viscosity of magma (melt, dissolved water, and crystals) in the magma chamber at the preeruptive conditions, and can be approximately obtained only by the bulk rock SiO2 and phenocryst content, using an empirical formula (Takeuchi, 2010). We have found some interesting relationships, such as (1) eruption styles and rates are correlated to preeruptive magma viscosity but not correlated to bulk rock composition, and (2) the gap (ratio) in eruption rates between explosive and effusive phases in a series of eruptions is proportional to preeruptive magma viscosity. We also propose, by combining (1) and (2), that (3) the radius (or width) of volcanic conduit is positively correlated with preeruptive magma viscosity. Our data also show that the eruptive magmas are divided into two types. One is the low-viscosity type (basalt ~ phenocryst-poor andesite), characterized by lava flow and sub-Plinian eruptions. The other is the high-viscosity type (phenocryst-rich andesite ~ rhyolite), characterized by lava dome and Plinian eruptions. The boundary is at about 104 Pa s. These two types may be closely linked to the magma generation processes (fractional/batch crystallization vs. extraction from a mushy magma chamber).

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  5. Depression Rating Scale for Children.

    ERIC Educational Resources Information Center

    Poznanski, Elva O.; And Others

    1979-01-01

    A Children's Depression Rating Scale (CDRS) was devised and tested on 30 inpatient children (6 to 12 years old) in a medical hospital. A high correlation was found between global ratings by two psychiatrists of severity of depression and scores on the CDRS. Journal availability: American Academy of Pediatrics, P.O. Box 1034, Evanston, IL 60204.…

  6. Satellite observations of the eruption of Dala Filla volcano in the Afar Depression, Ethiopia, during November 2008

    NASA Astrophysics Data System (ADS)

    Barnie, T.; Oppenheimer, C.

    2009-04-01

    The Dala Filla volcano lies in the north of the Erta Ale volcanic range in the Afar Depression, Ethiopia, and was the site of an effusive fissure eruption in November 2008. The volcano lies in a remote, sparsely populated region where access is difficult, so satellite images are the main source of information for reconstructing the eruption and estimating duration, volumes and rates. We present medium resolution thermal images acquired during the eruption to characterise its evolution and high resolution visual images acquired after the eruption to characterise the geomorphology of the resulting deposits. The significance of the eruption is assessed in the context of previous activity in the region using a revised geological interpretation of the area from satellite images.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  8. Do Plinian Eruptions of Mafic Magma Require Fast Ascent Rates?

    NASA Astrophysics Data System (ADS)

    Szramek, L. A.; Gardner, J. E.

    2008-12-01

    Although rare, mafic magma is known to erupt explosively in Plinian fashion. Given that models for such eruptions often invoke high viscosities as pre-requisite, mafic magmas erupting explosively seems to pose a quandary. One possibility is that such magmas can erupt explosively, if they ascend towards the surface very fast, creating conditions that lead to explosive degassing and fragmentation. In order to estimate how fast mafic magma ascends in such eruptions, we are carrying out series of isothermal decompression experiments to examine groundmass textures in natural samples from such eruptions to infer ascent rates. One eruption we are examining is the 122 B.C. Plinian eruption of hawaiite from Mt Etna. Prior work suggests that this magma was stored at 1025°C and 75 MPa before erupting. We find that the groundmass has a total crystallinity of 58 vol.%, consisting of 34 vol.% pyroxene, 20 vol.% plagioclase, and 4 vol.% Fe- Ti oxides. The area number densities are on the order of 3-7 x 10-2μm-2. Thus far, we have been unable to mimic its groundmass textures with either the single-step or multi-step decompression experiments, in which pressure dropped from 75 MPa to 13 MPa at rates ranging from 0.18 to 0.001 MPa s -1. Although the slowest decompression produced the correct groundmass assemblage and total crystallinity it has twice the plagioclase and far too little pyroxene. In addition, area number densities are 1-2 orders of magnitude less. Additionally, hopper shaped plagioclase is observed in all but the slowest experiment, whereas the natural sample contains only tabular to acicular plagioclase. Our results suggest that the textures of the hawaiite scoria cannot be explained by rapid ascent alone. One possibility is that the magma stalled and slowly crystallized prior to eruption. The additional microlites would have increased the viscosity of the melt, allowing the mafic magma to erupt in a Plinian style. In order to further test the rapid ascent model for

  9. Estimation of Eruption Source Parameters from Plume Growth Rate

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  10. 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

  11. Estimates of Lava Eruption Rates at Alba Patera, Mars

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  12. Orthodontic force decreases the eruption rate of rat incisors.

    PubMed

    Drevensek, M; Volk, J; Sprogar, S; Drevensek, G

    2009-02-01

    The aim of this study was to determine whether a force applied in an antero-posterior direction would adequately reduce incisor eruption. This is needed to achieve a constant direction of force which is one of the demands for a good model for studying orthodontic tooth movement. Twenty male Wistar rats aged 11-12 weeks were divided into two equal groups: in the appliance group, a superelastic closed coil spring (25 cN) was placed between the upper left first molar and the incisors. The control group consisted of animals without an appliance. In both groups, cuts were created on the labial surfaces of the upper and lower incisors. The distance from the gingival reference point to the midpoint of the cut was measured for 10 days at 2 day intervals. Upper incisor inclination was determined as the distance from the most mesial point of the upper left first molar to the incisal edge of the ipsilateral incisor on days 0 and 10. Statistical analysis was carried out using two-way analysis of variance and a Bonferroni post- test to estimate reliability. The eruption rates of the maxillary incisors in the appliance group were significantly decreased when compared with the control group during the whole experiment. In the appliance group, the eruption rates of the mandibular incisors were decreased more than those of the maxillary incisors (P<0.01). There was no difference in incisor inclination between the appliance and control groups on day 10 (P=0.81). The applied force of 25 cN in an antero-posterior direction diminished incisor eruption to a level which enabled a constant direction of orthodontic force for 10 days. PMID:19073954

  13. 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.

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

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2001-01-01

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

  15. Rate of Forgetting in Dementia and Depression.

    ERIC Educational Resources Information Center

    Hart, Robert P.; And Others

    1987-01-01

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

  16. Eruption rate, area, and length relationships for some Hawaiian lava flows

    NASA Technical Reports Server (NTRS)

    Pieri, David C.; Baloga, Stephen M.

    1986-01-01

    The relationships between the morphological parameters of lava flows and the process parameters of lava composition, eruption rate, and eruption temperature were investigated using literature data on Hawaiian lava flows. Two simple models for lava flow heat loss by Stefan-Boltzmann radiation were employed to derive eruption rate versus planimetric area relationship. For the Hawaiian basaltic flows, the eruption rate is highly correlated with the planimetric area. Moreover, this observed correlation is superior to those from other obvious combinations of eruption rate and flow dimensions. The correlations obtained on the basis of the two theoretical models, suggest that the surface of the Hawaiian flows radiates at an effective temperature much less than the inner parts of the flowing lava, which is in agreement with field observations. The data also indicate that the eruption rate versus planimetric area correlations can be markedly degraded when data from different vents, volcanoes, and epochs are combined.

  17. Automated estimation of mass eruption rate of volcanic eruption on satellite imagery using a cloud pattern recognition algorithm

    NASA Astrophysics Data System (ADS)

    Pouget, Solene; Jansons, Emile; Bursik, Marcus; Tupper, Andrew; Patra, Abani; Pitman, Bruce; Carn, Simon

    2014-05-01

    The need to detect and track the position of ash in the atmosphere has been highlighted in the past few years following the eruption Eyjafjallajokull. As a result, Volcanic Ash Advisory Centers (VAACs) are using Volcanic Ash Transport and Dispersion models (VATD) to estimate and predict the whereabouts of the ash in the atmosphere. However, these models require inputs of eruption source parameters, such as the mass eruption rate (MER), and wind fields, which are vital to properly model the ash movements. These inputs might change with time as the eruption enters different phases. This implies tracking the ash movement as conditions change, and new satellite imagery comes in. Thus, ultimately, the eruption must be detectable, regardless of changing eruption source and meteorological conditions. Volcanic cloud recognition can be particularly challenging, especially when meteorological clouds are present, which is typically the case in the tropics. Given the fact that a large fraction of the eruptions in the world happen in a tropical environment, we have based an automated volcanic cloud recognition algorithm on the fact that meteorological clouds and volcanic clouds behave differently. As a result, the pattern definition algorithm detects and defines volcanic clouds as different object types from meteorological clouds on satellite imagery. Following detection and definition, the algorithm then estimates the area covered by the ash. The area is then analyzed with respect to a plume growth rate methodology to get estimation of the volumetric and mass growth with time. This way, we were able to get an estimation of the MER with time, as plume growth is dependent on MER. To test our approach, we used the examples of two eruptions of different source strength, in two different climatic regimes, and for which therefore the weather during the eruption was quite different: Manam (Papua New Guinea) January 27 2005, which produced a stratospheric umbrella cloud and was

  18. Heart Rate Variability in Depressed Elderly

    PubMed Central

    Jindal, Ripu D.; Vasko, Raymond C.; Jennings, J. Richard; Fasiczka, Amy L.; Thase, Michael E.; Reynolds, Charles F.

    2009-01-01

    Objective The present study examines a measure of cardiac autonomic function, the heart rate variability (HRV), in a group of depressed elderly. Cardiac autonomic abnormalities have been implicated as a potential mediator of cardiovascular events and sudden death in depression. Because aging is associated with decreased cardiac vagal activity, it is possible that autonomic abnormalities are even more pronounced in the older depressed patients. Design Cross-sectional comparison between those with or without depression. The groups were compared using the Wilcoxon matched-pair sign-rank test. Setting Advanced Center for Interventions and Services Research for Late-Life Mood Disorders at University of Pittsburgh Medical Center. Participants Fifty-three patients with major depression (mean age: 73.3; SD: 7.4; range: 60–93) and an equal number of age and gender-matched subjects as a comparison group. Intervention None. Measurements Time domain and frequency domain measures of HRV. Results The groups did not differ in any of the time domain or frequency domain measures of HRV. As expected, subjects without depression displayed decreasing cardiac vagal function with aging (Spearman correlation coefficient rs = −0.33, p = 0.02). However, there was no significant change in vagal function with age in the depressed (r = 0.12, p = 0.38). Post-hoc analysis using Fisher’s zr transformation revealed that the relationship between age and cardiac vagal function was significantly different between the groups (z = 2.32, p = 0.02). Conclusions Our findings suggest that age has differential influence on vagal function in individuals with and without depression, a difference with implications for cardiovascular disease risk in depression. Prospective studies of cardiac vagal activity in depressed patients with or without preexisting cardiac disease in different age groups are needed to replicate and extend these findings. PMID:18978247

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  1. 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)

  2. Ice-melt rates in liquid-filled cavities during explosive subglacial eruptions

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    Subglacial eruptions are often associated with rapid penetration of overlying ice and release of large flow rates of water as jökulhlaups. Observations of recent subglacial eruptions indicate rapid syn-eruptive ice melting within liquid-filled subglacial cavities, but quantitative descriptions of possible heat transfer processes need to be developed. Calculations of heat flux from the ice cavity fluid to the melting ice surface indicate that up to 0.6 MW m-2 may be obtained for fluids undergoing single-phase free convection, similar to minimum estimates of heat flux inferred from observations of recent eruptions. Our model of boiling two-phase free convection in subglacial cavities indicates that much greater heat fluxes, in the range 3-5 MW m-2, can be obtained in the vent region of the cavity and may be increased further by momentum transfer from the eruption jet. Rapid magma-water heat transfer from fragmented magma is needed to sustain these heat fluxes. Similar heat fluxes are anticipated for forced convection of subcooled cavity water induced by momentum transfer from an eruption jet. These heat fluxes approach those required to explain jökulhlaup flow rates and rapid ice penetration rates by melting in some, but not all recent eruptions.

  3. 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.

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

    SciTech Connect

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

    1988-05-10

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

  5. 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.

  6. 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

  7. Development of an Interview-Based Geriatric Depression Rating Scale.

    ERIC Educational Resources Information Center

    Jamison, Christine; Scogin, Forrest

    1992-01-01

    Developed interview-based Geriatric Depression Rating Scale (GDRS) and administered 35-item GDRS to 68 older adults with range of affective disturbance. Found scale to have internal consistency and split-half reliability comparable to those of Hamilton Rating Scale for Depression and Geriatric Depression Scale. Concurrent validity, construct…

  8. 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.

  9. Reconstructing recent basaltic fissure eruptions in the Afar Depression, Ethiopia, using satellite imagery

    NASA Astrophysics Data System (ADS)

    Barnie, T. D.; Ferguson, D. J.; Oppenheimer, C.

    2009-12-01

    Since 2005, there have been numerous dike intrusions in the Manda-Hararo rift segment in central Afar, Ethiopia, as part of an on-going rifting event similar to that which occurred at Krafla, Iceland between 1975 and 1984. Two of the dikes have been associated with basaltic fissure eruptions, in August 2007 and in June 2009. A large fissure eruption also occurred in the Erta ‘Ale volcanic range in northern Afar in November 2008, which may be related to the activity further south. These eruptions took place in remote areas and lasted only a few days, making field observation almost impossible. We must therefore rely on the geomorphology and geochemistry of the erupted deposits, and syn-eruption satellite observations of thermally emitted radiance and gas emissions to reconstruct the evolution of these eruptions. Reconstruction of the eruptions is important for i) understanding the relationship between dike intrusion and fissure eruption dynamics ii) understanding the relationship between eruption dynamics and the resulting deposits, iii) interpreting the deposits of pre-historic eruptions from previous rifting events, and iv) estimating the hazard posed to the local population by further activity. In this study we use pre- and post-eruption high resolution ASTER and ALI images to map the morphology of the erupted material, and SEVIRI and MODIS time series of the eruptions to track evolution of the vent dynamics and lava flows. These datasets are augmented by oblique aerial and ground based photographic and FLIR surveys of the cooling lava flows and tephra. ASTER and ALI images are also used to map older erupted materials, which allow us to compare this rifting event with previous events to anticipate future activity.

  10. 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)...

  11. 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.

  12. 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…

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

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

    ERIC Educational Resources Information Center

    Teri, Linda; Truax, Paula

    1994-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Matthews, E.; Genareau, K. D.

    2015-12-01

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

  17. 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

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

    ERIC Educational Resources Information Center

    Hong, Sehee; Min, Sae-Young

    2007-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Petrie, G. J. D.

    2013-05-01

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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

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

    USGS Publications Warehouse

    Denlinger, R.P.

    1997-01-01

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

  6. Teacher and Parent Ratings of Children with Depressive Disorders

    ERIC Educational Resources Information Center

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

    2007-01-01

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

  7. 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.

  8. Wearable depression monitoring system with heart-rate variability.

    PubMed

    Roh, Taehwan; Hong, Sunjoo; Yoo, Hoi-Jun

    2014-01-01

    A wearable depression monitoring system is proposed with an application-specific system-on-chip (SoC) solution. The SoC is designed to accelerate the filtering and feature extraction of heart-rate variability (HRV) from the electrocardiogram (ECG). Thanks to the SoC solution and planar-fashionable circuit board (P-FCB), the monitoring system becomes a low-power wearable system. Its dimension is 14cm × 7cm with 5mm thickness covering the chest band for convenient usage. In addition, with 3.7V 500mAh battery, its lifetime is at least 10 hours. For user's convenience, the system is interfacing to smart phones through Bluetooth communication. With the features of the HRV and Beck depression inventory (BDI), the smart phone application trains and classifies the user's depression scale with 71% of accuracy. PMID:25570021

  9. 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.

  10. 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

  11. 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,…

  12. 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

  13. A comparison of the performance of rating scales used in the diagnosis of postnatal depression.

    PubMed

    Thompson, W M; Harris, B; Lazarus, J; Richards, C

    1998-09-01

    The results of a study looking into the association between thyroid status and depression in the postpartum period were reanalysed to explore the psychometric properties of the rating scales employed. The performance of the Edinburgh Postnatal Depression Scale was found to be superior to that of the Hospital Anxiety and Depression Scale in identifying RDC-defined depression, and on a par with the observer-rated Hamilton Rating Scale for Depression, which it also matched for sensitivity to change in mood state over time. The anxiety subscale of the Hospital Anxiety and Depression Scale performed well, reflecting the fact that anxiety represents a prominent symptom in postnatal depression. PMID:9761410

  14. 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.

  15. Style, Magnitude, and Rate of Deccan Lava Super-eruptions at K-T Boundary Times

    NASA Astrophysics Data System (ADS)

    Self, S.; Jay, A. E.; Widdowson, M.; Kelley, S. P.

    2005-12-01

    A study of 100s of individual lava flow units exposed in sections through the upper part of the main Deccan basaltic lava pile includes flow fields that were being erupted across the K-T boundary, about 65 Ma ago. Pahoehoe flow fields (the products of one eruption), each commonly 50 m, and exceptionally 80 m, thick, dominate the pile in the central Western Ghats region. The main landscape-builders are inflated sheet lobes between 15-30 m (occasionally 50 m) thick, with subordinate smaller inflated lobes and units down to the size of toes. These are typical tholeiitic pahoehoe sheet lobes, similar to those found in many other flood basalt provinces. Defining flow fields by several criteria permits an estimate of how many eruptions built up this portion of the Deccan pile, which is 30-40 in number. Based on the extent of the formations, some of the lava fields may be the longest yet described on Earth (1000 km). All formations studied have the same style lava flows, and, thus, fissure-fed, pahoehoe-flow-forming effusive volcanism dominated. Evidence from inter-flow horizons suggests extensive explosive activity also accompanied some eruptions (cf. Icelandic eruptions such as Eldgja AD 934). The 1,200-m-thick lava pile can be assigned to Deccan Group formations in the Wai Sub-group (WSG) by compositional fingerprinting, to the paleomagnetic timescale by polarity and declination measurements, and, by cross-correlation, to the radiometric time scale. During eruptions that built up the WSG lavas, which encompass the K-T boundary and the slightly younger paleomagnetic chron 29R-N boundary, the widespread nature of the formations attests that enormous volumes of lava were produced during each eruption. Volumes of eruptive units (flow fields) exceeded 2,000, and probably 5,000, cubic km of lava, and this was likely repeated in most eruptive events, each lasting many years. The age span of the WSG series of lava eruptions was so short that it falls within the errors of

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  17. The responsiveness of the Hamilton Depression Rating Scale.

    PubMed

    Faries, D; Herrera, J; Rayamajhi, J; DeBrota, D; Demitrack, M; Potter, W Z

    2000-01-01

    In clinical studies of antidepressants, the Hamilton Depression Rating Scale (HAMD) total score has been the gold standard instrument for establishing and comparing the efficacy of new treatments. However, the HAMD is a multidimensional measure, which may reduce its ability to detect differences between treatments, in particular, changes in core symptoms of depression. Two meta-analyses were conducted to compare the responsiveness of the HAMD total score with several published unidimensional subscale scores based upon core symptoms of depression. The first compared the above instrument's ability to detect differences between fluoxetine and placebo across eight studies involving over 1600 patients. The second analysis involved four studies and over 1200 patients randomized to tricyclic antidepressants and placebo. In both meta-analyses, the unidimensional core subscales outperformed the HAMD total score at detecting treatment differences. The implications of this on sample sizes and power for clinical studies will be discussed. In fact, studies based on the observed effect sizes from the core subscales would require approximately one-third less patients than studies based on the HAMD total score. Effect sizes from each individual HAMD item will also be presented to help explain the differences in responsiveness between the scales. PMID:10696827

  18. 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

  19. 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. PMID:12479083

  20. Autonomic dysfunction and heart rate variability in depression.

    PubMed

    Sgoifo, Andrea; Carnevali, Luca; Alfonso, Maria de los Angeles Pico; Amore, Mario

    2015-01-01

    Depression occurs in people of all ages across all world regions; it is the second leading cause of disability and its global burden increased by 37.5% between 1990 and 2010. Autonomic changes are often found in altered mood states and appear to be a central biological substrate linking depression to a number of physical dysfunctions. Alterations of autonomic nervous system functioning that promotes vagal withdrawal are reflected in reductions of heart rate variability (HRV) indexes. Reduced HRV characterizes emotional dysregulation, decreased psychological flexibility and defective social engagement, which in turn are linked to prefrontal cortex hypoactivity. Altogether, these pieces of evidence support the idea that HRV might represent a useful endophenotype for psychological/physical comorbidities, and its routine application should be advised to assess the efficacy of prevention/intervention therapies in a number of psychosomatic and psychiatric dysfunctions. Further research, also making use of appropriate animal models, could provide a significant support to this point of view and possibly help to identify appropriate antidepressant therapies that do not interefere with physical health. PMID:26004818

  1. 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.

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

    PubMed

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

    2016-07-01

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

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

    ERIC Educational Resources Information Center

    Shah, Farhana; Morgan, Sam B.

    1996-01-01

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

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

    USGS Publications Warehouse

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

    1994-01-01

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

  5. 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.

  6. 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

  7. Depression and Heart Rate Variability in Patients With Stable Coronary Heart Disease

    PubMed Central

    Gehi, Anil; Mangano, Dennis; Pipkin, Sharon; Browner, Warren S.; Whooley, Mary A.

    2009-01-01

    Context Depression is associated with low heart rate variability (HRV) in patients following myocardial infarction, suggesting that alterations in the autonomic nervous system may contribute to the adverse cardiac outcomes associated with depression. Whether depression is associated with low HRV in patients with stable coronary heart disease (CHD) is not known. Objective To examine the association between major depression and 24-hour HRV in patients with stable CHD. Design, Setting, and Participants Cross-sectional study of 873 outpatients with stable CHD recruited from outpatient clinics in the San Francisco Bay Area, California. Main Outcome Measures Major depression was assessed using the Computerized National Institute of Mental Health Diagnostic Interview Schedule. Heart rate variability was measured by 24-hour ambulatory electrocardiography. Results A total of 195 participants (22%) had major depression. Overall, we observed no association between depression and HRV as measured by time domain or frequency domain variables. Mean HRV was similar in participants with and without depression (all P values >.10), and participants with depression were no more likely than those without depression to have low HRV (all P values >.10). Conclusions We found no evidence of an association between depression and HRV in 873 outpatients with stable CHD. These findings raise questions about the potential role of HRV in the association between depression and cardiovascular disease. PMID:15939843

  8. Rates and predictors of depression in adoptive mothers: moving toward theory.

    PubMed

    Foli, Karen J; South, Susan C; Lim, Eunjung

    2012-01-01

    There are approximately 1.8 million adopted children living in the United States. Adoptive parents may experience depressive symptoms and put their children at risk for negative outcomes. The results of this study describe the rates of depression in 300 adoptive mothers and associations with hypothesized explanatory variables, which predict approximately half of the variance in maternal depressive symptoms: expectations of themselves as mothers, the child, and family and friends; feeling of rest; past and present psychiatric difficulties (self-esteem, history of depression); and interpersonal variables (bonding, marital satisfaction, perceived support). These findings are useful in planning effective interventions to mitigate depressive symptoms. PMID:22293610

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

    PubMed Central

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

    2007-01-01

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

  10. Depression

    MedlinePlus

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

  11. Depression

    MedlinePlus

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2015-11-01

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

  14. 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

  15. Development and validation of the Affective Self Rating Scale for manic, depressive, and mixed affective states.

    PubMed

    Adler, Mats; Liberg, Benny; Andersson, Stig; Isacsson, Göran; Hetta, Jerker

    2008-01-01

    Most rating scales for affective disorders measure either depressive or hypomanic/manic symptoms and there are few scales for hypomania/mania in a self-rating format. We wanted to develop and validate a self-rating scale for comprehensive assessment of depressive, manic/hypomanic and mixed affective states. We developed an 18-item self-rating scale starting with the DSM-IV criteria for depression and mania, with subscales for depression and mania. The scale was evaluated on 61 patients with a diagnosis of affective disorder, predominantly bipolar disorder type I, using Montgomery-Asberg Depression Rating Scale (MADRS), Hypomania Interview Guide-Clinical version (HIGH-C) and Clinical Global Impression scale, modified for bipolar patients (CGI-BP) as reference scales. Internal consistency of the scale measured by Cronbach's alpha was 0.89 for the depression subscale and 0.91 for the mania subscale. Spearman's correlation coefficients (two-tailed) between the depression subscale and MADRS was 0.74 (P<0.01) and between mania subscale and HIGH-C 0.80 (P<0.01). A rotated factor analysis of the scale supported the separation of symptoms in the mania and depression subscale. We established that the self-rating scales sensitivity to identify mixed states, with combined cut-offs on the MADRS and HIGH-C as reference, was 0.90 with a specificity of 0.71. The study shows that the Affective Self Rating Scale is highly correlated with ratings of established interview scales for depression and mania and that it may aid the detection of mixed affective states. PMID:18569776

  16. Estimating Thermal Energy Emission and Eruption Rates at Guatemalan Volcanoes Using Thermal Data From a FLIR Camera, ASTER and MODIS Data Sources

    NASA Astrophysics Data System (ADS)

    Bowman, L. J.; Kapelanczyk, L.; Colvin, A. S.; Matias, O.; Rose, W. I.

    2008-12-01

    Analysis of thermal images taken with a Forward-Looking Infrared camera has allowed us to establish a baseline data set for three open vent volcanoes in Guatemala that vary in composition from dacite (Santiaguito) to basalt (Fuego and Pacaya). This allows for the evaluation of eruption rates using remote sensing and provides satellite thermal remote sensing validations. The field data were collected during two field trips in 2008. The Santiaguito data have been atmospherically corrected and analyzed to allow estimates of the emitted thermal energy and also the equivalent eruption rate (Rose, et al 2008). Using similar techniques, data from Pacaya volcano were analyzed to obtain estimated emission of thermal energy along with observations of vent morphology. The long term goal is to employ a variety of thermal remote sensing tools, including data comparison from ASTER and MODIS sources, in order to closely monitor eruption rates at open vent volcanoes, such as Santiaguito, Fuego and Pacaya. Ultimately, eruption rate estimates at these volcanoes may lead to improved hazard forecasts.

  17. 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

  18. Depression

    MedlinePlus

    ... it might motivate the person to go for treatment. Treating Depression Your doctor or mental health expert can often treat your depression successfully. Different therapies seem to work for different people. For instance, ...

  19. Depressants

    MedlinePlus

    Drug Fact Sheet Depressants Overview Includes barbiturates (barbs), benzodiazepines (benzos) and sedative-hypnotics. Depressants will put you ... unsafe, increasing the likelihood of coma or death. Benzodiazepines were developed to replace barbiturates, though they still ...

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

    PubMed Central

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

    2016-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  3. Acigöl rhyolite field, Central Anatolia (part 1): high-resolution dating of eruption episodes and zircon growth rates

    NASA Astrophysics Data System (ADS)

    Schmitt, Axel K.; Danišík, Martin; Evans, Noreen J.; Siebel, Wolfgang; Kiemele, Elena; Aydin, Faruk; Harvey, Janet C.

    2011-12-01

    Protracted pre-eruptive zircon residence is frequently detected in continental rhyolites and can conflict with thermal models, indicating briefer magma cooling durations if scaled to erupted volumes. Here, we present combined U-Th and (U-Th)/He zircon ages from the Acigöl rhyolite field (Central Anatolia, Turkey), which is part of a Quaternary bimodal volcanic complex. Unlike other geochronometers, this approach dates crystallization and eruption on the same crystals, allowing for internal consistency testing. Despite the overall longevity of Acigöl rhyolite volcanism and systematic trends of progressive depletion in compatible trace elements and decreasing zircon saturation temperatures, we find that zircon crystallized in two brief pulses corresponding to eruptions in the eastern and western part of the field during Middle and Late Pleistocene times, respectively. For Late Pleistocene zircon, resolvable differences exist between interior (average: 30.7 ± 0.9 ka; 1 σ error) and rim (21.9 ± 1.3 ka) crystallization ages. These translate into radial crystal growth rates of ~10-13 to 10-14 cm/s, broadly consistent with those constrained by diffusion experiments. Rim crystallization and (U-Th)/He eruption ages (24.2 ± 0.4 ka) overlap within uncertainty. Evidence for brief zircon residence at Acigöl contrasts with many other rhyolite fields, suggesting that protracted zircon crystallization in, or recycling from, long-lived crystal mushes is not ubiquitous in continental silicic magma systems. Instead, the span of pre-eruptive zircon ages is consistent with autochthonous crystallization in individual small-volume magma batches that originated from basaltic precursors.

  4. Dopamine, depressive symptoms, and decision-making: the relationship between spontaneous eye blink rate and depressive symptoms predicts Iowa Gambling Task performance.

    PubMed

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

    2016-02-01

    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 eye blink rates, 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). The regression results revealed that eye blink rate moderated the relationship between depressive symptoms and advantageous decisions on the Iowa Gambling Task, in which individuals with more depressive symptomatology and high blink rates (higher striatal dopamine D2 receptor density) performed better on the task. Our computational modeling results demonstrated that depressive symptoms alone were associated with enhanced loss-aversive behavior, whereas 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  6. Validation of the Spanish Center for Epidemiological Studies Depression and Zung Self-Rating Depression Scales: A Comparative Validation Study

    PubMed Central

    Arevalo, Jorge M.; Chavez, Kristhy; Vilela, Ana; Lazo, Maria; Huapaya, Julio

    2012-01-01

    Background Depressive disorders are leading contributors to burden of disease in developing countries. Research aiming to improve their diagnosis and treatment is fundamental in these settings, and psychometric tools are widely used instruments to support mental health research. Our aim is to validate and compare the psychometric properties of the Spanish versions of the Center for Epidemiological Studies Depression Scale (CES-D) and the Zung Self-Rating Depression Scale (ZSDS). Methodology/Principal Findings A Spanish version of the CES-D was revised by 5 native Spanish speaking psychiatrists using as reference the English version. A locally standardized Spanish version of the ZSDS was used. These Spanish versions were administered to 70 patients with a clinical diagnosis of DSM-IV Major Depressive Episode (MDE), 63 without major depression but with clinical diagnosis of other psychiatric disorders (OPD), and 61 with no evidence of psychiatric disorders (NEP). For both scales, Cronbach's alpha (C-α) and Hierarchical McDonald Omega for polychoric variables (MD-Ω) were estimated; and receiver operating characteristics (ROC) analysis performed. For the CES-D and ZSDS scales, C-α was 0.93 and 0.89 respectively, while MD-Ω was 0.90 and 0.75 respectively. The area under the ROC curve in MDE+OPD was 0.83 for CES-D and 0.84 for ZSDS; and in MDE+NEP was 0.98 for CES-D and 0.96 for ZSDS. Cut-off scores (co) for the highest proportions of correctly classified (cc) individuals among MDE+OPD were ≥29 for CES-D (sensitivity (ss) = 77.1/specificity (sp) = 79.4%/(cc) = 78.2%) and ≥47 for ZSDS (ss = 85.7%/sp = 71.4%/cc = 78.9%). In the MDE+NEP, co were ≥24 for the CES-D (ss = 91.4%/sp = 96.7%/cc = 93.9%) and ≥45 for the ZSDS (ss = 91.4%/sp = 91.8%/cc = 91.6%). Conclusion Spanish versions of the CES-D and ZSDS are valid instruments to detect depression in clinical settings and could be useful for both epidemiological

  7. 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…

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

    PubMed

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

    2016-01-01

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

  9. 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

  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. Seasonality of volcanic eruptions

    NASA Astrophysics Data System (ADS)

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

    2004-04-01

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

  13. Depression

    MedlinePlus

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

  14. Depressants

    MedlinePlus

    ... system. Doctors use them to treat things like insomnia or anxiety . But if depressant drugs (like sedatives, ... Other long-term effects include: impaired sexual function insomnia and other sleep problems breathing problems convulsions (similar ...

  15. Depressants

    MedlinePlus

    ... marketed in the United States. Common places of origin Generally, legitimate pharmaceutical products are diverted to the illicit market. Teens can obtain depressants from the family medicine cabinet, friends, family members, the Internet, doctors, ...

  16. Can Satellite-Based Sensors, Hand-Held Thermal Imagers and Thermal Infrared Radiometers Calculate Reliable Eruption Rates at Active Lava Flows, Domes and Lakes?

    NASA Astrophysics Data System (ADS)

    Harris, A. J.

    2004-12-01

    Thermal data provide viable means of extracting eruption rates at active lava flows, domes and lakes. The initial algorithm, developed since 1994, uses total heat flux (Q), extracted from satellite-sensor-derived thermal images of the active lava body to extract eruption rate (E) using E = Q / ρ [c Δ T + f L]. Here ρ and c are lava density and specific heat capacity, Δ T is lava cooling, f is fractional crystallization and L is latent heat of crystallization. Later it was shown that this reduces to a linear relationship: E = a Q + b, where a and b are defined by values assumed for ρ , c, Δ T, f, and L. We present three case studies that: (1) demonstrate the variety of thermal data and activity styles that can be used in this approach, and (2) validate the approach through cross-checks with independent, field-based data: (I) Stromboli: Satellite and thermal imager-based lava flow eruption rates. A safe, easy and rapid method to calculate lava effusion rates using hand-held thermal image data was developed in June 2003 at Stromboli (Italy). FLIR data were used as input to the thermal effusion rate model, previously applied to satellite data, allowing automated effusion rate extraction. A comparison between a thermally-derived (0.2 - 0.9 m3/s) and dimensionally-derived (i.e. channel depth x width x velocity) effusion rate (0.6 m3/s) showed excellent agreement. In addition, the comparison between FLIR-derived effusion rates and satellite (AVHRR) derived values showed a good correlation (R = 0.9). (II) Santiaguito: Satellite-derived eruption rates for a lava dome A time series of 21 Landsat ETM+ and TM images acquired during 1986-2003, were used to calculate eruption rates at Santiaguito dome (Guatemala) to yield a time-averaged effusion rate of 0.4 m3/s. Field-based flow dimension and velocity measurements during 1987 and 2000-03 yielded a values of 0.6±0.3 and 0.5±0.2 m3/s which compared with an ETM+ derived values of 0.7±0.1 and 0.5±0.1 m3/s, respectively

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  18. 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. PMID:20447874

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

    PubMed Central

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

    2016-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

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

    PubMed

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

    2013-11-01

    Greater levels of socioeconomic position (SEP) are generally associated with better health. However results from previous studies vary across race/ethnicity and health outcomes. Further, the majority of previous studies do not account for the effects of life course SEP on health nor the effects of racial discrimination, which could moderate the effects of SEP on health. Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we examined the relationship between a life course SEP measure on depressive symptoms and self-rated health. A life course SEP was constructed for each participant, using a framework that included parental education and occupation along with respondents' highest level of education and occupation. Interaction terms were created between life course SEP and racial discrimination to determine whether the association between SEP and health was moderated by experiences of racial discrimination. Analyses revealed that higher levels of life course SEP were inversely related to depressive symptoms. Greater life course SEP was positively associated with favorable self-rated health. Racial discrimination was associated with more depressive symptoms and poorer self-rated health. Analyses indicated a significant interaction between life course SEP and racial discrimination on depressive symptoms in the full sample. This suggested that for respondents with greater levels of SEP, racial discrimination was associated with reports of more depressive symptoms. Future research efforts should be made to examine whether individuals' perceptions and experiences of racial discrimination at the interpersonal and structural levels limits their ability to acquire human capital as well as their advancement in education and occupational status. PMID:24161083

  2. Depression

    MedlinePlus

    ... to eat at all Not being able to sleep, or sleeping too much Feeling very tired Feeling hopeless, irritable, anxious, or guilty Aches or pains, headaches, cramps, or digestive problems Thoughts of death or suicide Depression is a disorder of the brain. There are a variety of ...

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

    PubMed

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

    2015-01-01

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

  4. Rating scales for states for anxiety, depression, mania and schizophrenia. A multiaxial approach.

    PubMed

    Kastrup, M; Bech, P; Rafaelsen, O J

    1986-01-01

    Rating scales are considered to be an efficient instrument in the assessment of treatment effect, and during the last 25 years a number of rating scales has been constructed for measuring states of anxiety, depression, mania and schizophrenia. The paper describes some of the most frequently used scales. Time has come to coordinate the existing rating scales and to agree upon common operational definitions in the judgement of psychopathological symptoms. Basic practical guidelines to be used in both clinical practice and research are given. PMID:2881427

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

    NASA Astrophysics Data System (ADS)

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

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

  7. Self-Concept, Social Skills, and Teacher Ratings of Behavior as Predictors of Depression in Learning Disabled Children.

    ERIC Educational Resources Information Center

    Spoto, Philip M.; And Others

    The role of depression as related to symptoms of social behavior, teacher ratings of behavior and intellectual ability was examined for 58 children (7-14 years old) with learning disabilities. Subjects were administered the Children's Depression Inventory, and those (N=16) scoring one standard deviation below the mean were designated nondepressed,…

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

    PubMed

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

    2015-04-30

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

  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 Carroll rating scale for depression. II. Factor analyses of the feature profiles.

    PubMed

    Smouse, P E; Feinberg, M; Carroll, B J; Park, M H; Rawson, S G

    1981-03-01

    Factor analyses were conducted for the Hamilton depression rating scale (HRS) and the self administered Carroll counterpart (CRS). The factor loadings for the respective first factors were similar; those for the respective second factors showed strict sign consistency but only moderate consistency of magnitude; the loadings for the respective third factors showed no particular consistency. The first three CRS and first three HRS factor scores were computed for each individual and correlations were computed from these factor scores. The first and second factors were highly correlated but the third factors were negatively correlated indicating that they were not measuring the same thing. The first factors of the CRS and HRS correlated highly with their respective raw total scores and were indices of the severity of illness. The self-administered CRS (with matching weights) is a credible alternative to the HRS for routine clinical assessment of the severity of depression. PMID:7272610

  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. The Symptom Frequency Characteristics of the Hamilton Depression Rating Scale and Possible Symptom Clusters of Depressive Disorders in Korea: The CRESCEND Study

    PubMed Central

    Park, Young-Nam; Jae, Young-Myo; Jun, Tae-Youn; Lee, Min-Soo; Kim, Jae-Min; Jeong, Seung-Hee; Kim, Jung-Bum

    2011-01-01

    Objective This study analyzed the symptom frequencies of 17-item Hamilton Depression Rating Scale (HDRS-17) to understand the characteristics of each item and to propose the possible symptoms clusters. Methods From psychiatric clinics of 18 Hospitals in Korea, 1,183 patients, diagnosed with major depressive disorder (psychotic or non-psychotic), dysthymia or depressive disorder not otherwise specified. according to DSM-IV criteria, participated in this study from January 2006 to August 2008. The frequencies of each item of HDRS-17 were analyzed according to sex and severity. In addition, we compared this study with a previous study performed in England by Hamilton and with two studies performed in Korea by Kim et al. Results The frequencies of HDRS-17 items varied widely in this study, ranging from 95.8% in work and activities to 37.4% in loss of weight. But, depressed mood, psychic anxiety and work and activities items exhibited constant and higher frequency or rank regardless of study, the severity of depression or sex. Insomnia early, somatic gastrointestinal, genital symptoms and insight showed relatively constant but lower frequency or rank in disregard of studies or the clinical variables. Other symptoms had variable frequencies or ranks according to the variable clinical situations (culture, time, sex, severity of depression). Conclusion We propose three clusters of symptoms in depressive disorders: core symptoms cluster, an associated symptoms, and a situation-specific symptoms. We can use these possible symptom clusters of depression in simplifying diagnosis of depression, increasing diagnostic specificity in special situation and indexing disease severity. PMID:22216040

  13. 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.

  14. Relationship between placebo response rate and clinical trial outcome in bipolar depression.

    PubMed

    Iovieno, Nadia; Nierenberg, Andrew A; Parkin, Susannah R; Hyung Kim, Daniel Ju; Walker, Rosemary S W; Fava, Maurizio; Papakostas, George I

    2016-03-01

    The aim of this work is to investigate the impact of placebo response rates on the relative risk of response to drug versus placebo in randomized, double-blind, placebo-controlled clinical trials of pharmacological therapy in Bipolar Depression (BPD). Medline/PubMed publication databases were searched for randomized, double-blind, placebo-controlled trials of oral drugs used as monotherapy for the treatment of BPD. The search was limited to articles published between January 1980 and September 2015. Data extracted from 12 manuscripts and one poster with yet unpublished results, representing a total of 17 clinical trials were pooled (n = 6578). Pooled response rates for drug and placebo were 55.1% and 39.2%, corresponding to a risk ratio (RR) for responding to active treatment versus placebo of 1.29 (p < 0.001). Clinical response was defined as a 50% or greater reduction in depression scores, baseline to endpoint. A higher placebo response rate correlated with a significantly lower RR of responding to pharmacotherapy versus placebo (p = 0.002). The pooled drug and placebo response rates for studies with a placebo response rate ≤ 30% were 50.5% versus 26.6%, while corresponding values from studies with a placebo response rate >30 were 55.0% versus 41.6%. These results suggest that the relative efficacy of the active drug compared to placebo in clinical trials for BPD is highly heterogeneous across studies with different placebo response rates, with a worse performance in showing a superiority of the drug versus placebo for studies with placebo response rates >30%. It is important to maintain placebo response rates below this critical threshold, since this is one of the most challenging obstacles for new treatment development in BPD. PMID:26736040

  15. 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

  16. 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

  17. Heart rate variability and treatment outcome in major depression: a pilot study.

    PubMed

    Jain, Felipe A; Cook, Ian A; Leuchter, Andrew F; Hunter, Aimee M; Davydov, Dmitry M; Ottaviani, Cristina; Tartter, Molly; Crump, Caroline; Shapiro, David

    2014-08-01

    Variations in heart rate variability (HRV) have been associated with major depressive disorder (MDD), but the relationship of baseline HRV to treatment outcome in MDD is unclear. We conducted a pilot study to examine associations between resting baseline HRV and MDD treatment outcome. We retrospectively tested several parameters of HRV in an MDD treatment study with escitalopram (ESC, N=26) to generate a model of how baseline HRV related to treatment outcome, and cross-validated the model in a separate trial of MDD treatment with Iyengar yoga (IY, N=16). Lower relative power of very low frequency (rVLF) HRV at baseline predicted improvement in depressive symptoms when adjusted for age and gender (R2>.43 and p<0.05 for both trials). Although vagal parasympathetic measures were correlated with antidepressant treatment outcome, their predictive power was not significant after adjusting for age and gender. In conclusion, baseline resting rVLF was associated with depression treatment outcome in two independent MDD treatment studies. These results should be interpreted with caution due to limited sample size, but a strength of this study is its validation of the rVLF predictor in an independent sample. rVLF merits prospective confirmation as a candidate biomarker. PMID:24769434

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

    PubMed Central

    Watts, Sam; Leydon, Geraldine; Birch, Brian; Prescott, Philip; Lai, Lily; Eardley, Susan; Lewith, George

    2014-01-01

    Objectives To systematically review the literature pertaining to the prevalence of depression and anxiety in patients with prostate cancer as a function of treatment stage. Design Systematic review and meta-analysis. Participants 4494 patients with prostate cancer from primary research investigations. Primary outcome measure The prevalence of clinical depression and anxiety in patients with prostate cancer as a function of treatment stage. Results We identified 27 full journal articles that met the inclusion criteria for entry into the meta-analysis resulting in a pooled sample size of 4494 patients. The meta-analysis of prevalence rates identified pretreatment, on-treatment and post-treatment depression prevalences of 17.27% (95% CI 15.06% to 19.72%), 14.70% (95% CI 11.92% to 17.99%) and 18.44% (95% CI 15.18% to 22.22%), respectively. Pretreatment, on-treatment and post-treatment anxiety prevalences were 27.04% (95% CI 24.26% to 30.01%), 15.09% (95% CI 12.15% to 18.60%) and 18.49% (95% CI 13.81% to 24.31%), respectively. Conclusions Our findings suggest that the prevalence of depression and anxiety in men with prostate cancer, across the treatment spectrum, is relatively high. In light of the growing emphasis placed on cancer survivorship, we consider that further research within this area is warranted to ensure that psychological distress in patients with prostate cancer is not underdiagnosed and undertreated. PMID:24625637

  19. 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. PMID:27185312

  20. 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. PMID:25600920

  1. 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

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

    PubMed Central

    Mihai, Adriana; Ricean, Alina; Voidazan, Septimiu

    2014-01-01

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

  3. Continuous overnight observation of human premolar eruption.

    PubMed

    Risinger, R K; Proffit, W R

    1996-01-01

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

  4. 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.

  5. Early dysautonomia detected by heart rate variability predicts late depression in female patients following mild traumatic brain injury.

    PubMed

    Sung, Chih-Wei; Lee, Hsin-Chien; Chiang, Yung-Hsiao; Chiu, Wen-Ta; Chu, Shu-Fen; Ou, Ju-Chi; Tsai, Shin-Han; Liao, Kuo-Hsing; Lin, Chien-Min; Lin, Jia-Wei; Chen, Gunng-Shinng; Li, Wei-Jiun; Wang, Jia-Yi

    2016-04-01

    Depression is one of the frequent complications following a mild traumatic brain injury (mTBI). Recent research indicated that abnormalities in the autonomic nervous system (ANS) can be evaluated by a noninvasive power spectral analysis of the heart rate variability (HRV). In this study, we investigated whether a frequency-domain analysis of HRV was correlated with late depression in mTBI patients. In total, 181 patients diagnosed with mTBI and 83 volunteers as healthy controls were recruited in 2010-2014. Beck Depression Inventory (BDI) scores were used to evaluate depression in the 1st week of assessment and at 1.5-, 3-, 6-, 12-, and 18-month follow-ups. Correlation and logistic regression analyses of the 1st week HRV parameters with BDI scores at 18 months were performed in individual female mTBI patients. Female mTBI patients were more vulnerable to depression accompanied by reduced HRV compared to healthy controls. Over time, depression was aggravated in female mTBI patients but was alleviated in male mTBI patients. A significantly lower parasympathetic proportion of the ANS was noted at 18 months with respect to the 1st week in female mTBI patients. In addition, depression in female mTBI patients at 18 months after injury was significantly correlated with a decrease in the parasympathetic proportion of the ANS in the 1st week (ρ = -0.411; p < .05). Dysautonomia resulted in higher risks of depression in female mTBI patients. We concluded that early dysautonomia following an mTBI contributes to late depression in female mTBI patients. PMID:26560198

  6. Polymorphic light eruption

    MedlinePlus

    ... outdoors. Wear a sun hat. Wear sunglasses with UV protection. Use a lip balm with sunscreen. Alternative Names Polymorphic light eruption; Photodermatosis; PMLE Images Polymorphic light eruption on ...

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

    PubMed Central

    Worboys, Michael

    2013-01-01

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

  8. Comparing Dynamics in Eruptive and Non-Eruptive Flares

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  9. An examination of the base rates of post-concussion symptoms: the influence of demographics and depression.

    PubMed

    Garden, Natalie; Sullivan, Karen A

    2010-01-01

    Post-concussion syndrome (PCS) is a controversial constellation of cognitive, emotional, and physical symptoms that some patients experience following a mild traumatic brain injury or concussion. PCS-like symptoms are commonly found in individuals with depression, pain, and stress, as well as healthy individuals. This study investigated the base rate of PCS symptoms in a healthy sample of 96 participants and examined the relationship between these symptoms, depression, and sample demographics. PCS symptoms were assessed using the British-Columbia Post-Concussion Symptom Inventory. Depression was measured using the Beck Depression Inventory II. Results demonstrated that: The base rate of PCS was very high; there was a strong positive relationship between depression and PCS; and demographic characteristics were not related to PCS in this sample. These findings are broadly consistent with literature suggesting a significant role for non-neurological factors in the expression of PCS symptomatology. This study adds to the growing body of literature that calls for caution in the clinical interpretation of results from PCS symptom inventories. PMID:20146116

  10. 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

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

    PubMed Central

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

    2011-01-01

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

  12. 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…

  13. 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.

  14. 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.

  15. Investigation of heart rate variability in major depression patients using wavelet packet transform.

    PubMed

    Akar, Saime Akdemir; Kara, Sadık; Bilgiç, Vedat

    2016-04-30

    Studies conducted in major depression (MD) patients have reported a high risk of cardiac morbidity as a result of the relationship between changed cardiovascular activity (CA) and autonomic dysfunctions. The investigation of heart rate variability (HRV) gives valuable idea about variances in autonomic CA of MD patients. To get this knowledge, frequency-domain HRV analysis is frequently performed using Fourier transformation (FT) or discrete-wavelet transformation (DWT) to decompose the data into high-frequency (HF) and low-frequency (LF) bands. Nevertheless, it has been reported that the FT is not useful for nonstationary HRV signals and the DWT does not ensure required frequency boundaries of each band. This study aims to compare the frequency-domain HRV features using wavelet-packet-transform (WPT) with absolutely excellent approximation to required band ranges between the controls and patients. In addition to LF and HF band energies, sympathovagal balance that indicates the variation of sympathetic and parasympathetic activities were compared between two groups. Patients had a significantly lower HF energy, higher values of LF energy and higher LF/HF ratio. Our results recommend that impairments in coordination between parasympathetic and sympathetic behavior in MD patients can be assessed by HRV analysis using WPT with high resolution decomposition for needed bands. PMID:27086252

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  18. Bayesian analysis of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Ho, Chih-Hsiang

    1990-10-01

    The simple Poisson model generally gives a good fit to many volcanoes for volcanic eruption forecasting. Nonetheless, empirical evidence suggests that volcanic activity in successive equal time-periods tends to be more variable than a simple Poisson with constant eruptive rate. An alternative model is therefore examined in which eruptive rate(λ) for a given volcano or cluster(s) of volcanoes is described by a gamma distribution (prior) rather than treated as a constant value as in the assumptions of a simple Poisson model. Bayesian analysis is performed to link two distributions together to give the aggregate behavior of the volcanic activity. When the Poisson process is expanded to accomodate a gamma mixing distribution on λ, a consequence of this mixed (or compound) Poisson model is that the frequency distribution of eruptions in any given time-period of equal length follows the negative binomial distribution (NBD). Applications of the proposed model and comparisons between the generalized model and simple Poisson model are discussed based on the historical eruptive count data of volcanoes Mauna Loa (Hawaii) and Etna (Italy). Several relevant facts lead to the conclusion that the generalized model is preferable for practical use both in space and time.

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

    PubMed

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

    2015-11-01

    The purpose of the current study was to evaluate the validity of a single-item, self-rated mental health (SRMH) measure in the identification of women at risk for depression and posttraumatic stress disorder (PTSD). Baseline data of 239 low-income women participating in an intimate partner violence (IPV) intervention study were analyzed. PTSD was measured with the Davidson Trauma Scale. Risk for depression was determined using the Edinburgh Postnatal Depression Scale. SRMH was assessed with a single item asking participants to rate their mental health at the time of the baseline interview. Single-item measures can be an efficient way to increase the proportion of patients screened for mental health disorders. Although SRMH is not a strong indicator of PTSD, it may be useful in identifying pregnant women who are at increased risk for depression and need further comprehensive assessment in the clinical setting. Future research examining the use of SRMH among high-risk populations is needed. PMID:26535762

  20. The variation of magma discharge during basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Wadge, G.

    1981-12-01

    The rate at which basaltic magma is discharged varies substantially during many eruptions. An individual eruption has an eruption rate ( Qe), the volumetric rate of discharge averaged over the whole or a major part of an eruption, and an effusion rate ( Qf), the volumetric flux rate at any given time. In many examples Qf soon reaches a maximum value after a short period of waxing flow, partly because of magmatic expansion, and then falls more slowly in the later parts of the eruption. The release of elastic strain energy from stored magma and the sub-volcanic reservoir during eruption can produce an exponential form of such waning flow. Comparison of the eruption rates of the historic eruptions of Mauna Loa, Kilauea and Etna shows that for each volcano there is a trend of decreasing Qe with increasing duration of eruption. This relationship is not predicted by a simple elastic model of magma release. Two additional processes are invoked to explain the eruptive histories of these volcanoes: modification of the eruptive conduits, and the continued supply of magma from depth during eruption. Conduits evolving from dikes to plugs by wall-rock erosion or freezing of magma can result in increased early values of Qf and the maintenance of very low values of Qf values for long periods later in the eruption. Discharge variations during three specific eruptions are discussed in detail. Paricutin (1943-1952) had exponentially waning flow, with a time constant of about three years, that is consistent with a deep reservoir. The waning flow of Hekla's 1947-1948 eruption showed some of the characteristics of conduit modification, whilst the 1959 Kilauea Iki eruption is interpreted in terms of a closed system with varying magma rheology.

  1. 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

  2. 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. PMID:10688326

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

    PubMed

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

    2016-01-01

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

  4. 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

  5. Automated Detection of Eruptive Structures for Solar Eruption Prediction

    NASA Astrophysics Data System (ADS)

    Georgoulis, Manolis K.

    2012-07-01

    The problem of data processing and assimilation for solar eruption prediction is, for contemporary solar physics, more pressing than the problem of data acquisition. Although critical solar data, such as the coronal magnetic field, are still not routinely available, space-based observatories deliver diverse, high-quality information at such a high rate that a manual or semi-manual processing becomes meaningless. We discuss automated data analysis methods and explain, using basic physics, why some of them are unlikely to advance eruption prediction. From this finding we also understand why solar eruption prediction is likely to remain inherently probabilistic. We discuss some promising eruption prediction measures and report on efforts to adapt them for use with high-resolution, high-cadence photospheric and coronal data delivered by the Solar Dynamics Observatory. Concluding, we touch on the problem of physical understanding and synthesis of different results: combining different measures inferred by different data sets is a yet-to-be-done exercise that, however, presents our best opportunity of realizing benefits in solar eruption prediction via a meaningful, targeted assimilation of solar data.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  7. Depression and Self-Rated Health Among Rural Women Who Experienced Adolescent Dating Abuse: A Mixed Methods Study.

    PubMed

    Burton, Candace W; Halpern-Felsher, Bonnie; Rehm, Roberta S; Rankin, Sally H; Humphreys, Janice C

    2016-03-01

    This study used mixed methods to examine the experiences and health of rural, young adult women (N = 100) who self-reported past experience of physical, emotional and verbal, sexual, and relational abuse in adolescent dating relationships. Few studies have examined the lasting health ramifications of adolescent dating abuse adolescent dating abuse in rural populations, and almost no mixed methods studies have explored adolescent dating abuse. Participants completed questionnaires on demographics, relationship behaviors, and mental health symptoms. A subsample (n = 10) of participants also completed semi-structured, in-depth interviews with the primary investigator. Results suggest that depressive symptoms and self-rating of health in these women are associated with particular kinds and severity of abusive experiences, and that adolescent dating abuse has ramifications for health and development beyond the duration of the original relationship. Self-rated health (SRH) was inversely associated with abusive behaviors in the relationship, whereas depressive symptoms were positively correlated with such behaviors. Self-rated health was also negatively correlated with depressive symptoms. The results of this study represent an important step toward establishing lifetime health risks posed by adolescent dating abuse. PMID:25392389

  8. Rates of depression and participation in senior centre activities in community-dwelling older persons.

    PubMed

    Fulbright, S A

    2010-06-01

    The purpose of this study was to determine the role that senior citizen centres play in decreasing depression in community-dwelling older persons. A quantitative cross-sectional design was utilized. A questionnaire was used to determine demographic and lifestyle data. The dependent variable, depression symptoms, was measured using the 15-point Geriatric Depression Scale. Eighty-eight per cent stated that they attend for the friends and social support. Second, the study demonstrated that community-dwelling older persons can have those needs fulfilled at the senior centres. Ninety-four per cent of them have made close friends at their centres. Ninety-four per cent stated that their lives had improved since attending the senior centre. Eighty-six per cent felt they had made friends on whom they could rely when needed. PMID:20584235

  9. An erupted compound odontoma.

    PubMed

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

    2014-01-01

    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. PMID:24729109

  10. 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…

  11. CRY1 Variations Impacts on the Depressive Relapse Rate in a Sample of Bipolar Patients

    PubMed Central

    Monti, Barbara; De Ronchi, Diana; Serretti, Alessandro

    2015-01-01

    Objective A relevant part of the social and personal burden caused by Bipolar Disorder (BD) is related to depressive phases. Authors investigated the genetic impact of a set of variations located in CRY1, a gene involved in the control of the circadian rhythms, towards depressive episodes in a sample of bipolar patients from the STEP-BD sample. As a secondary analysis, CYR1 variations were analyzed as predictors of sleep disruption. Methods 654 bipolar patients were included in the analysis. Data were available genome-wide. The part of the genome coding for the CRY1 was imputed and pruned according to standards in the field. 7 SNPs were available for the analysis. A correction for multitesting was applied and we had sufficient power (0.80) to detect a small-medium effect size (0.22) between two allelic frequencies each one represented by at least 300 subjects. Results Intronic rs10861688 was associated with the number of depressive events corrected for the times patients were assessed during the period of observation. In particular, AA subjects (n=21) had 4.46±3.15 events, AG (n=141) had 3.08±3.17 and GG (n=342) 2.65±2.97 (p=0.0048, beta=-0.22). No other significant associations were reported. Conclusion We bring further evidence that genes involved in the regulation of circadian rhythms may be relevant to depressive bipolar phases. Independent confirmation analyses are mandatory. PMID:25670954

  12. 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…

  13. 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:…

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  15. The variation of magma discharge during basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Wadge, G.

    The different types of magmatic flow in basaltic eruptions are discussed, and processes explaining the eruptive history of specific volcanoes are investigated. The effusion rate curve is divided into waxing and waning flow parts, and the ideal, elastic response of the reservoir in the waning phase is analytically shown. Historical eruption rates of Mauna Loa, Kilauea, and Etna are presented, demonstrating that for each volcano there is a trend of decreasing rate with increasing duration of eruption, a relationship not predicted by a simple elastic model of magma release. The eruptive histories of these volcanoes is explained by the processes of modification of the eruptive conduits and the continued supply of magma from depth during eruption. Discharge variations from Paricutin, Hekla, and Kilauea Iki are discussed in detail.

  16. 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

  17. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2016-05-01

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

  20. Major depression

    MedlinePlus

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

  1. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

  2. Thin slice ratings of client characteristics in intake assessments: predicting symptom change and dropout in cognitive therapy for depression.

    PubMed

    Sasso, Katherine E; Strunk, Daniel R

    2013-08-01

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

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. Dome forming eruptions: a global hazards database

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  6. Rate and predictors of postpartum depression in a 22-year follow-up of a cohort of earthquake survivors in Armenia.

    PubMed

    Demirchyan, Anahit; Petrosyan, Diana; Armenian, Haroutune K

    2014-06-01

    Disasters have serious long-term impact on mental health for those exposed. The aim of this study was to identify predictors of postpartum depression among survivors of the 1988 devastating earthquake in Armenia. A nested case-control design was applied to investigate postpartum depression in a large-scale cohort of survivors followed between 1990 and 2012. From an original group of 725 adults who were assessed for psychopathology in 1990, 146 women reported having a delivery after the earthquake and were included in this study. Women with postpartum depression were identified using Edinburgh Postnatal Depression Scale. A logistic regression model was fitted to identify the predictors of postpartum depression. Of the 146 women, 19 (13.0%) had postpartum depression. Five independent predictors of postpartum depression were identified: number of woman's stressful life events (odds ratio (OR)=2.06), her prior history of postpartum depression (OR=16.98), delivering sick/dead neonate (OR=13.65), poor living standards during the post-earthquake decade (OR=5.77), and perceiving oneself reliable in 1990 (OR=0.24). Anxiety in 1990 was marginally significantly related to the outcome (OR=3.75). The rate of postpartum depression in this 22-year cohort was similar to that among the Armenian general population. Earthquake exposure was not related to postpartum depression, indicating that the impact of disaster-related trauma diminishes over time. The identified predictors provided evidence to develop interventions targeting groups of women most prone to postpartum depression under such circumstances. PMID:24435250

  7. Seismic damage before eruptions as a tool to map pre-eruptive mechanics: worldwide average patterns

    NASA Astrophysics Data System (ADS)

    Schmid, A.; Grasso, J. R.

    2010-12-01

    Volcanic eruptions and earthquakes are shown to interact at different time and space scales, from a few hundreds of km for VEI>5 eruptions and Mag>7 earthquakes (Linde and Sacks, 1998), down to a few km with Mag<3 VT earthquakes that are contemporary to regular small effusive eruptions. When distances are normalized by the seismic fault length, VEI>0 and Mag>5, Lemarchand and Grasso, (2007) suggest that the seismicity rate before eruptions follows inverse Omori’s law (Omori, 1896) similar to the one observed for earthquakes, but with possible different exponent values. Given this similarity, we were interested to further compare the properties of the upper crust damage contemporary to worldwide eruptions (expressed through the seismicity), to the properties of the upper crust damage triggered by the standard tectonic loading of worldwide earthquakes. Using two empirical laws (Gutemberg-Richter law, Omori law) ETAS model well reproduces the main observed properties of tectonic seismicity. It will here be considered as null hypothesis. Differences from ETAS model or global tectonic seismicity patterns are used to track down the seismic signature of the magma movement and the pre-eruptive mechanisms. First, we analyzed the crustal response to loading, thanks to patterns of seismicity: i) before 525 Mag>7 earthquakes, USGS worldwide catalog 1973-2009, ii) before earthquakes of synthetic ETAS simulation, iii) before 1179 worldwide eruptions from the Smithsonian Institution catalog, 1973-2009. Using stacked sequences of seismic events before eruption times and for different classes of eruptions sizes, we found that the parameters of inverse Omori law significantly differ from the expected values of ETAS model or the ones of real tectonic seismicity: i) The productivity in foreshocks scales linearly to VEI; ii) The exponent of the power-law increase of foreshock rates vary with the eruption size. For VEI<2 eruptions, the 0.49 p-value of foreshock sequences is smaller

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

    PubMed

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

    1996-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  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. The 2010 Eruption of Merapi Volcano, Java, Indonesia: Petrological Insights into Magma Dynamics and Eruptive Behaviour

    NASA Astrophysics Data System (ADS)

    Gertisser, R.; Handley, H.; Preece, K.; Reagan, M.; Berlo, K.; Barclay, J.; Herd, R.

    2012-04-01

    The violent eruption of Merapi volcano (Central Java) that started on 26 October 2010 was the volcano's largest since 1872 and the deadliest event since 1930. Before 2010, Merapi's more recent (historical) eruptive activity was repeatedly characterised by periods of slow lava dome extrusion punctuated by gravitational dome failures, generating small-volume pyroclastic density currents (PDCs) with runout distances of typically less than 10 km. The unforeseen, large-magnitude events in 2010 were unusual in many respects: (1) the eruption was short-lived and started with an explosive phase that was not preceded by a lava dome at the surface; (2) between 31 October and 4 November, a lava dome appeared and grew rapidly within the summit crater, exceeding growth rates observed at the peak of the penultimate eruption in 2006 by a factor of ~ 22; (3) during the most vigorous eruptive phase on 5 November, at least one PDC travelled more than 15 km (more than twice the distance of the largest flows in 2006) beyond the summit along the Gendol river valley, causing widespread devastation on Merapi's south flank; (4) in a late phase of the eruption, pumice-rich PDCs were produced, forming a thin veneer on top of the deposits of the largest PDCs from 5 November; (5) ash emissions from sustained eruption columns resulted in ash fall tens of kilometres from the volcano, affecting, amongst other areas, the volcano's western slopes and the city of Yogyakarta ~ 25 km to the south; and (6) the total deposited volume in 2010, based on provisional estimates, may have been ~ 10 times higher than that of other recent eruptions. Here we report and present new geochemical, Sr-Nd-O isotope and U-series data for the volcanic products (lava dome fragments, magmatic inclusions, scoria, pumice and ash) from various stages of the 2010 eruption of Merapi. These data are discussed in the context of other recent to historical, typically less explosive, dome-forming eruptions to elucidate the driving

  12. Depression among Women with Primary Infertility attending an Infertility Clinic in Riyadh, Kingdom of Saudi Arabia: Rate, Severity, and Contributing Factors

    PubMed Central

    Al-Homaidan, Homaidan Turki

    2011-01-01

    Background Infertility is a severely distressing experience for many couples. Depression is considered as one of the main psychological disorders associated with infertility and it may significantly affect the life of infertile individuals, their treatment, and follow-up. Objective The objective of the study was to determining the prevalence and predisposing factors of depressive disorders among the infertile compared to fertile women. Methodology Rate of depression was explored by this cross-sectional study carried out among women attending In-Vitro Fertilization Clinic (91 infertile women) and Well Baby Clinic (94 fertile women) at King Abdulaziz Medical City (KAMC) in Riyadh, KSA. Self administrated questionnaire including Beck Depression Inventory (BDI) was used. Mean BDI score was measured and its relation with different variables was explored, such as age, educational level, duration of infertility, pressure from family members, miscarriages and support from husband. Results This study showed that 49 (53.8%) of the infertile women and 35 (37.2%) of the fertile women had depression. Mean BDI score between infertile and fertile women was significantly different (p <0.001). Infertile women were found to be more severely depressed (p =0.014). Among the infertile women, those who had pressure from family members for not getting pregnant were more depressed than those with no such pressure (P=0.001). Conclusion Depression is more common and severe in infertile women than fertile women. Pressure from family to get pregnant is a significant contributor to depression. Caregivers should routinely screen infertile women for depression during and after treatment for infertility and manage concomitantly. PMID:23267288

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

    PubMed

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

    2015-09-30

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

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

    PubMed

    Guindon, G Emmanuel; Boyle, Michael H

    2012-03-01

    General measures of self-rated health are collected routinely in national health surveys and widely used in the analyses of determinants of health and health care utilization. However, these subjective assessments can be influenced by health expectations (contextualized beliefs about health) that may vary systematically across individuals and be associated with their socio-demographic characteristics. Our objective is to contrast the impact of health expectations associated with respondent characteristics (reporting heterogeneity) on self-rated feelings of sadness, lowness or depression obtained from general population samples in France and Vietnam. Based on self ratings and ratings in response to common anchoring vignettes depicting different levels of depression, we used nationally representative data from the World Health Survey conducted in France (2002) and Vietnam (2002-2003) and a modification of the standard probit model to test and adjust for reporting heterogeneity associated with individual characteristics. We find evidence of reporting heterogeneity within France and Vietnam and across the two countries. In particular we find that, when adjusted for reporting heterogeneity, sex is no longer significantly associated with self-rated feelings of sadness, lowness or depression in France. Given the absence of clear biological markers in the definitions of depressive disorders and the substantial impact reporting heterogeneity is shown to have, measures of depressive disorders based on self-reports should be interpreted with caution. PMID:22411195

  16. Interacting filamentary eruptions in magnetised plasmas

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  17. Lower third molar eruption following orthodontic treatment.

    PubMed

    Salehi, P; Danaie, S Momene

    2008-01-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  19. 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. Sympathetic Solar Filament Eruptions

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  1. 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

  2. An Erupted Silent Tumour.

    PubMed

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

    2016-07-01

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

  3. Pregnancy limits lung function during exercise and depresses metabolic rate in the skink Tiliqua nigrolutea.

    PubMed

    Munns, Suzanne L; Edwards, Ashley; Nicol, Stewart; Frappell, Peter B

    2015-03-01

    High gestational loads have been associated with a range of ecological costs, such as decreased locomotor ability; however, the physiological mechanisms that underpin these changes are poorly understood. In this study, breathing patterns, metabolic rates, lung volume and lung diffusing capacity were measured at rest and during exercise in the pregnant skink Tiliqua nigrolutea. Breathing patterns were largely unaffected by gestation; however, decreases in metabolic rate (rate of oxygen consumption) in the late stages of pregnancy induced a relative hyperventilation. The reductions in metabolic rate during late pregnancy prevent the calculation of the maintenance cost of pregnancy based on post-partum and neonatal metabolic rates. Despite the high relative litter mass of 38.9±5.3%, lung diffusing capacity was maintained during all stages of pregnancy, suggesting that alterations in diffusion at the alveolar capillary membrane were not responsible for the relative hyperventilation. Lung volume was increased during pregnancy compared with non-pregnant females, but lung volume was significantly lower during pregnancy compared with post-partum lung volume. Pregnant females were unable to produce the same metabolic and ventilatory changes induced by exercise in non-pregnant females. This lack of ability to respond to increased respiratory drive during exercise may underpin the locomotor impairment measured during gestation in previous studies. PMID:25788728

  4. 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

  5. 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

  6. 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...

  7. 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...

  8. Generalized eruptive syringomas.

    PubMed

    Jamalipour, Mahnaz; Heidarpour, Mitra; Rajabi, Parvin

    2009-01-01

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

  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. 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

  12. Seismogenic lavas and explosive eruption forecasting.

    PubMed

    Lavallée, Y; Meredith, P G; Dingwell, D B; Hess, K-U; Wassermann, J; Cordonnier, B; Gerik, A; Kruhl, J H

    2008-05-22

    Volcanic dome-building episodes commonly exhibit acceleration in both effusive discharge rate and seismicity before explosive eruptions. This should enable the application of material failure forecasting methods to eruption forecasting. To date, such methods have been based exclusively on the seismicity of the country rock. It is clear, however, that the rheology and deformation rate of the lava ultimately dictate eruption style. The highly crystalline lavas involved in these eruptions are pseudoplastic fluids that exhibit a strong component of shear thinning as their deformation accelerates across the ductile to brittle transition. Thus, understanding the nature of the ductile-brittle transition in dome lavas may well hold the key to an accurate description of dome growth and stability. Here we present the results of rheological experiments with continuous microseismic monitoring, which reveal that dome lavas are seismogenic and that the character of the seismicity changes markedly across the ductile-brittle transition until complete brittle failure occurs at high strain rates. We conclude that magma seismicity, combined with failure forecasting methods, could potentially be applied successfully to dome-building eruptions for volcanic forecasting. PMID:18497822

  13. 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. PMID:22021205

  14. 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.

  15. Impaired heart rate regulation and depression of cardiac chronotropic and dromotropic function in polymicrobial sepsis

    PubMed Central

    Hoover, Donald B.; Ozment, Tammy R.; Wondergem, Robert; Li, Chuanfu; Williams, David L.

    2014-01-01

    The scope of cardiac pathophysiology in sepsis has not been fully defined. Accordingly, we evaluated the effects of sepsis on heart rate (HR), HR variability, and conduction parameters in a murine model of sepsis. Electrocardiograms were recorded non-invasively from conscious mice before and after cecal ligation and puncture (CLP) or sham surgery. Responses of isolated atria to tyramine and isoproterenol were quantified to assess the functional state of sympathetic nerves and postjunctional sensitivity to adrenergic stimulation. CLP mice had lower HR compared to sham at 16-18 h post-surgery (Sham: 741±7 beats per min, CLP: 557±31 beats per min, n=6/group, P<0.001), and there was significant prolongation of the PR, QRS and QTc intervals. Slowing of HR and conduction developed within 4-6 h after CLP and were preceded by a decrease in HR variability. Treatment of CLP mice with isoproterenol (5 mg/kg, i.p.) at 25 h post-surgery failed to increase HR or decrease conduction intervals. The lack of in vivo response to isoproterenol cannot be attributed to hypothermia since robust chronotropic and inotropic responses to isoproterenol were evoked from isolated atria at 25 and 30° C. These findings demonstrate that impaired regulation of HR (i.e, reduced HR variability) develops before the onset of overt cardiac rate and conduction changes in septic mice. Subsequent time-dependent decreases in HR and cardiac conduction can be attributed to hypothermia and would contribute to decreased cardiac output and organ perfusion. Since isolated atria from septic mice showed normal responsiveness to adrenergic stimulation, we conclude that impaired effectiveness of isoproterenol in vivo can be attributed to reversible effects of systemic factors on adrenergic receptors and/or post-receptor signaling. PMID:25271380

  16. Hydrological Disturbances Caused By Explosive Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Major, J. J.; Pierson, T. C.; Spicer, K. R.; Mark, L.; Yamakoshi, T.; Suwa, H.

    2014-12-01

    Explosive eruptions can drastically alter hydrogeomorphic regimes of drainage basins. The extent and degree of eruption-induced alteration scale with eruption magnitude, volcanic process, and basin proximity to a volcano. The most important effects of explosive eruptions on basin hydrology are ones that alter production and routing of runoff: (a) vegetation damage, which decreases (or eliminates) interception and evapotranspiration (ET); (b) reduction of surface infiltration owing to tephra deposition, which increases overland flow; (c) alteration of stream-channel hydraulics, which enables efficient transport of water and sediment; and (d) alterations to drainage networks, which accelerate or delay geomorphic response. In combination, these effects alter flood magnitude and frequency and rates of sediment transport. Vegetation loss allows more water to fall directly to the ground surface and reduces ET, which affects soil moisture, water storage and runoff pathways. Tephra fall, which typically paves the landscape with nearly impervious sediment, can reduce infiltration by as much as 2 orders of magnitude compared to pre-eruption rates and can increase direct runoff from near zero to as much as 90%. Even very thin layers (2-5 mm) of extremely fine tephra can increase runoff and decrease lag times between peak rainfall and peak runoff. Volcanic sedimentation in river valleys can increase channel gradient, reduce planform resistance, and smooth channel hydraulics, allowing for more efficient flow routing and producing larger, flashier flows. Hydrological effects of eruptive disturbance can linger for decades, but the most extreme effects typically last but a few years. However, lake formation through tributary blockage by thick deposits can delay response and extend the hydrologic legacy of eruptive disturbances. Failures of lake-impounding dams can produce large floods that renew downstream channel instability and rejuvenate headwater erosion.

  17. 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

  18. 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.

  19. Mid-ocean ridge eruptions as a climate valve

    NASA Astrophysics Data System (ADS)

    Tolstoy, Maya

    2015-03-01

    Seafloor eruption rates and mantle melting fueling eruptions may be influenced by sea level and crustal loading cycles at scales from fortnightly to 100 kyr. Recent mid-ocean ridge eruptions occur primarily during neap tides and the first 6 months of the year, suggesting sensitivity to minor changes in tidal forcing and orbital eccentricity. An ~100 kyr periodicity in fast-spreading seafloor bathymetry and relatively low present-day eruption rates at a time of high sea level and decreasing orbital eccentricity suggest a longer-term sensitivity to sea level and orbital variations associated with Milankovitch cycles. Seafloor spreading is considered a small but steady contributor of CO2 to climate cycles on the 100 kyr time scale; however, this assumes a consistent short-term eruption rate. Pulsing of seafloor volcanic activity may feed back into climate cycles, possibly contributing to glacial/interglacial cycles, the abrupt end of ice ages, and dominance of the 100 kyr cycle.

  20. 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…

  1. 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.

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  3. Reproducibility of the ST-segment depression/heart rate analysis of the exercise electrocardiographic test in asymptomatic middle-aged population.

    PubMed

    Lehtinen, R; Sievanen, H; Viik, J; Vuori, I; Malmivuo, J

    1997-05-15

    The reproducibility of the ST-segment depression against heart rate (ST/HR) hysteresis, ST/HR index, and end-exercise ST depression between the repeated exercise electrocardiographic tests were determined in 61 asymptomatic middle-aged subjects. The findings support the clinical utility of the ST/HR hysteresis, but it is noteworthy that the results also suggest that the magnitude of change in the exercise electrocardiographic variables, which has to be observed to make the clinician confident that a real diagnostic change has occurred, is surprisingly large. PMID:9165173

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

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.

    2015-10-01

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

  5. 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

  6. Acneiform facial eruptions

    PubMed Central

    Cheung, Melody J.; Taher, Muba; Lauzon, Gilles J.

    2005-01-01

    OBJECTIVE To summarize clinical recognition and current management strategies for four types of acneiform facial eruptions common in young women: acne vulgaris, rosacea, folliculitis, and perioral dermatitis. QUALITY OF EVIDENCE Many randomized controlled trials (level I evidence) have studied treatments for acne vulgaris over the years. Treatment recommendations for rosacea, folliculitis, and perioral dermatitis are based predominantly on comparison and open-label studies (level II evidence) as well as expert opinion and consensus statements (level III evidence). MAIN MESSAGE Young women with acneiform facial eruptions often present in primary care. Differentiating between morphologically similar conditions is often difficult. Accurate diagnosis is important because treatment approaches are different for each disease. CONCLUSION Careful visual assessment with an appreciation for subtle morphologic differences and associated clinical factors will help with diagnosis of these common acneiform facial eruptions and lead to appropriate management. PMID:15856972

  7. 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.

  8. 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.

  9. 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

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

    PubMed

    Tatsumi, Yoshiyuki; Suzuki-Kamata, Keiko

    2014-01-01

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

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

    PubMed

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

    2000-02-28

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

  12. 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

  13. 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.

  14. Eruption on Io

    NASA Technical Reports Server (NTRS)

    1996-01-01

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

  15. Kimberlite ascent and eruption.

    PubMed

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

    2007-12-13

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

  16. Small-scale eruptive filaments on the quiet sun

    NASA Technical Reports Server (NTRS)

    Hermans, Linda M.; Martin, Sara F.

    1986-01-01

    A study of a little known class of eruptive events on the quiet sun was conducted. All of 61 small-scale eruptive filamentary structures were identified in a systematic survey of 32 days of H alpha time-lapse films of the quiet sun acquired at Big Bear Solar Observatory. When fully developed, these structures have an average length of 15 arc seconds before eruption. They appear to be the small-scale analog of large-scale eruptive filaments observed against the disk. At the observed rate of 1.9 small-scale eruptive features per field of view per average 7.0 hour day, the rate of occurence of these events on the sun were estimated to be greater than 600 per 24 hour day.. The average duration of the eruptive phase was 26 minutes while the average lifetime from formation through eruption was 70 minutes. A majority of the small-scale filamentary sturctures were spatially related to cancelling magnetic features in line-of-sight photospheric magnetograms. Similar to large-scale filaments, the small-scale filamentary structures sometimes divided opposite polarity cancelling fragments but often had one or both ends terminating at a cancellation site. Their high numbers appear to reflect the much greater flux on the quiet sun. From their characteristics, evolution, and relationship to photospheric magnetic flux, it was concluded that the structures described are small-scale eruptive filaments and are a subset of all filaments.

  17. 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.

  18. 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

  19. The Eruptive Behavior of Klyuchevskoy Volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Rose, S.; Ramsey, M.

    2008-12-01

    Klyuchevskoy volcano, one of the most active volcanoes in the northern Pacific, is located on the Kamchatka Peninsula in eastern Russia at the junction between the Kurile-Kamchatka and Aleutian Island Arcs. Its remote location and diversity of eruption styles make satellite-based monitoring and characterization of its eruptive activity essential. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor was launched in December 1999 on the NASA Terra satellite and has proven effective for the detection and monitoring of volcanic eruptions and their associated products. The goal of this investigation is to determine how well data from a broad spectral range at spatial resolutions under 100m/pixel can be used to characterize the 2005 and 2007 eruptions of a remote volcano during the harsh northern Pacific winter. The ASTER data presented here are supplemented by hand samples collected from the 2005 basaltic lava flows as well as high-spatial resolution thermal infrared data collected by a Forward Looking Infrared (FLIR) camera during field campaigns in August 2005 and 2007. Collectively, these data provide details regarding the composition, eruption rate, and eruptive mechanisms. Analysis of the data from all three ASTER subsystems reveals four main eruptive phases: a precursory, explosive, explosive-effusive, and cooling phase. These phases correlate to a gradual increase in maximum brightness temperatures followed by a rapid decrease. Close examination of FLIR data and digital photographs reveal the presence of a breakout point approximately 90 m below the rim of the nested summit crater, indicating a flow had breached the nested crater and traveled down the Krestovsky channel during both eruptions. Laboratory- derived TIR spectral data of the 2005 hand samples indicate good agreement with those obtained by ASTER after being reduced to the same spectral resolution. However, inherent errors of the spectra at longer wavelength indicate the

  20. Weakened rate-dependent depression of Hoffmann's reflex and increased motoneuron hyperactivity after motor cortical infarction in mice

    PubMed Central

    Lee, S; Toda, T; Kiyama, H; Yamashita, T

    2014-01-01

    Abnormal reflexes associated with spasticity are considered a major determinant of motor impairments occurring after stroke; however, the mechanisms underlying post-stroke spasticity remain unclear. This may be because of the lack of suitable rodent models for studying spasticity after cortical injuries. Thus, the purpose of the present study was to establish an appropriate post-stroke spasticity mouse model. We induced photothrombotic injury in the rostral and caudal forelimb motor areas of mice and used the rate-dependent depression (RDD) of Hoffmann's reflex (H-reflex) as an indicator of spastic symptoms. To detect motoneuron excitability, we examined c-fos mRNA levels and c-Fos immunoreactivity in affected motoneurons using quantitative real-time reverse transcription PCR and immunohistochemical analysis, respectively. To confirm the validity of our model, we confirmed the effect of the anti-spasticity drug baclofen on H-reflex RDDs 1 week post stroke. We found that 3 days after stroke, the RDD was significantly weakened in the affected muscles of stroke mice compared with sham-operated mice, and this was observed for 8 weeks. The c-fos mRNA levels in affected motoneurons were significantly increased in stroke mice compared with sham-operated mice. Immunohistochemical analysis revealed a significant increase in the number of c-Fos-positive motoneurons in stroke mice compared with sham-operated mice at 1, 2, 4, and 8 weeks after stroke; however, the number of c-Fos-positive motoneurons on both sides of the brain gradually decreased over time. Baclofen treatment resulted in recovery of the weakened RDD at 1 week post stroke. Our findings suggest that this is a viable animal model of post-stroke spasticity. PMID:24434515

  1. Weakened rate-dependent depression of Hoffmann's reflex and increased motoneuron hyperactivity after motor cortical infarction in mice.

    PubMed

    Lee, S; Toda, T; Kiyama, H; Yamashita, T

    2014-01-01

    Abnormal reflexes associated with spasticity are considered a major determinant of motor impairments occurring after stroke; however, the mechanisms underlying post-stroke spasticity remain unclear. This may be because of the lack of suitable rodent models for studying spasticity after cortical injuries. Thus, the purpose of the present study was to establish an appropriate post-stroke spasticity mouse model. We induced photothrombotic injury in the rostral and caudal forelimb motor areas of mice and used the rate-dependent depression (RDD) of Hoffmann's reflex (H-reflex) as an indicator of spastic symptoms. To detect motoneuron excitability, we examined c-fos mRNA levels and c-Fos immunoreactivity in affected motoneurons using quantitative real-time reverse transcription PCR and immunohistochemical analysis, respectively. To confirm the validity of our model, we confirmed the effect of the anti-spasticity drug baclofen on H-reflex RDDs 1 week post stroke. We found that 3 days after stroke, the RDD was significantly weakened in the affected muscles of stroke mice compared with sham-operated mice, and this was observed for 8 weeks. The c-fos mRNA levels in affected motoneurons were significantly increased in stroke mice compared with sham-operated mice. Immunohistochemical analysis revealed a significant increase in the number of c-Fos-positive motoneurons in stroke mice compared with sham-operated mice at 1, 2, 4, and 8 weeks after stroke; however, the number of c-Fos-positive motoneurons on both sides of the brain gradually decreased over time. Baclofen treatment resulted in recovery of the weakened RDD at 1 week post stroke. Our findings suggest that this is a viable animal model of post-stroke spasticity. PMID:24434515

  2. 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

  3. 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/ ...

  4. Spontaneous Eruption of Premolar Associated with a Dentigerous Cyst

    PubMed Central

    Luna, Anibal Henrique Barbosa

    2016-01-01

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

  5. 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.

  6. Glucose utilization in the medial prefrontal cortex correlates with serotonin turnover rate and clinical depression in alcoholics.

    PubMed

    Williams, Wendol; Reimold, Matthias; Kerich, Michael; Hommer, Dan; Bauer, Michael; Heinz, Andreas

    2004-12-30

    We measured the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF), regional cerebral glucose uptake (rCMRglc) as assessed with positron emission tomography in the medial prefrontal cortex (PFC) and severity of clinical depression (Beck's Depression Inventory, BDI) in detoxified male alcoholics and age-matched healthy men. In alcoholics, the severity of clinical depression was negatively correlated with rCMRglc in the medial PFC and positively with CSF 5-HIAA concentrations. A voxel-based analysis showed that the strongest correlation between CSF 5-HIAA levels and rCMRglc was found in alcoholics in the left orbitofrontal and medial PFC (BA10 and BA11); no significant correlations were observed among healthy control subjects. This pilot study indicates that a dysfunction of medial PFC may interact with central serotonin turnover and negative mood states during early abstinence. PMID:15664793

  7. 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

  8. 2-D Numerical Simulation of Eruption Clouds : Effects of Turbulent Mixing between Eruption Cloud and Air

    NASA Astrophysics Data System (ADS)

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

    2001-05-01

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

  9. 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.

  10. 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.

  11. The Variable Climate Impact of Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Graf, H.

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  13. The 1984 Mauna Loa eruption and planetary geolgoy

    NASA Technical Reports Server (NTRS)

    Moore, Henry J.

    1987-01-01

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

  14. 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

  15. 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…

  16. 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.

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

    SciTech Connect

    Valentine, G.A.

    1993-11-01

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

  18. Modeling Explosive Eruptions at Kīlauea, Hawai'i

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  19. 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

  20. 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.

  1. Microlite Characterization of Basaltic Pumice from Two Plinian Eruptions of Chikurachki Volcano

    NASA Astrophysics Data System (ADS)

    Pena, A.; Jones, C. D.; Danner, T.; Orange, E. N.; Szramek, L. A.

    2014-12-01

    Plinian eruptions, though rare, are poorly understood volcanic processes. One hypothesis relating to the volcanicity that results in such eruptions require fast ascent to allow gas to remain within the magma, resulting in fragmentation. In unmonitored eruptions the prevailing method to determine ascent rates is to compare microlite textures of experimental and natural samples. We are investigating two mafic Plinian eruptions of the Chikurachki volcano, one from 1853 and an ancient eruption. Preliminary microlite texture analyses showed a notable difference between the two eruptions. Through comparing textures with that of previously analyzed mafic Plinian eruptions, one has shown a similarity to the Fontana deposit of Masaya volcano while the other a similarity to the 122 B.C.E. Mt. Etna eruption. This suggests that the ascent histories of the two mafic Plinian eruptions being studied at Chikurachki volcano are different. This also suggest the cause of the variance in the two eruptions is more complicated than a simple rapid ascent. More work is required on all known mafic Plinian eruptions to try and determine how the magma is able to erupt so explosively.

  2. Geyser's Eruptive Activity in Broadband Seismic Records

    NASA Astrophysics Data System (ADS)

    Kugaenko, Yulia; Saltykov, Vadim

    2010-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Koyaguchi, Takehiro; Suzuki, Yujiro

    2016-04-01

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

  4. 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.

  5. 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

  6. 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

  7. Erupted complex odontoma delayed eruption of permanent molar.

    PubMed

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

    2013-01-01

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

  8. 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)

  9. 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.

  10. Granulomatous Drug Eruptions.

    PubMed

    Dodiuk-Gad, Roni P; Shear, Neil H

    2015-07-01

    Granuloma formation is usually regarded as a means of defending the host from persistent irritants of either exogenous or endogenous origin. Noninfectious granulomatous disorders of the skin encompass a challenging group of diseases owing to their clinical and histologic overlap. Drug reactions characterized by a granulomatous reaction pattern are rare, and defined by a predominance of histiocytes in the inflammatory infiltrate. This review summarizes current knowledge on the various types of granulomatous drug eruptions, focusing on the 4 major types: interstitial granulomatous drug reaction, drug-induced accelerated rheumatoid nodulosis, drug-induced granuloma annulare, and drug-induced sarcoidosis. PMID:26143430