WorldWideScience

Sample records for central volcanic systems

  1. Magma chamber processes in central volcanic systems of Iceland

    DEFF Research Database (Denmark)

    Þórarinsson, Sigurjón Böðvar; Tegner, Christian

    2009-01-01

    New field work and petrological investigations of the largest gabbro outcrop in Iceland, the Hvalnesfjall gabbro of the 6-7 Ma Austurhorn intrusive complex, have established a stratigraphic sequence exceeding 800 m composed of at least 8 macrorhythmic units. The bases of the macrorhythmic units...... olivine basalts from Iceland that had undergone about 20% crystallisation of olivine, plagioclase and clinopyroxene and that the macrorhythmic units formed from thin magma layers not exceeding 200-300 m. Such a "mushy" magma chamber is akin to volcanic plumbing systems in settings of high magma supply...... rate including the mid-ocean ridges and present-day magma chambers over the Iceland mantle plume. The Austurhorn central volcano likely formed in an off-rift flank zone proximal to the Iceland mantle plume during a major rift relocation....

  2. Soil gas measurements around the most recent volcanic system of metropolitan France (Lake Pavin, Massif Central)

    International Nuclear Information System (INIS)

    Soil gas monitoring techniques (CO2, O2, 222Rn, 4He) are used in the geographical context of the recent volcanic system of Lake Pavin (Puy-de-Dome), to get a better knowledge of local gaseous emissions, in order to establish whether or not this system can present evidence of reactivation. Concentrations up to 100% CO2 and 50 ppm of helium are measured in a narrow geographical area (Escarot Mofette), together with a magmatic origin for these gases. Radon activity in the Mofette area is quite high, but does not show, compared to surrounding areas, enrichments as high as those measured for CO2 or helium. Hourly records of these radon activities, performed during several weeks, suggest the existence of pulsed radon exhalation in the Mofette area. The period of this pulsation is around 40 days but its origin remains poorly understood. Apart from this Mofette, no evidence of gas originating from depth is highlighted. (authors)

  3. The monitoring and forecasting system of Etna volcanic plumes for reinforcement of the aviation safety on the central Mediterranean

    Science.gov (United States)

    Coltelli, M.

    2009-12-01

    Since 1979 explosive activity of Etna volcano produced many short-lived and two long-lived ash plume forming eruptions that disrupted the operations of Catania and Reggio Calabria airports and create difficulties to the air traffic in the central Mediterranean region. National Institute of Geophysics and Volcanology (INGV) is charged of the monitoring of Etna eruptive phenomena. It cooperates with the National Civil Protection Department, the Agency for Civil Aviation (ENAC), the Air Traffic Control company (ENAV) and the Italian Air Force for warning continuously the aviation authorities about the occurring of the ash cloud on Sicilian airspace and the ash fallout on Catania airport. The objective of INGV is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present on multispectral infrared satellite imagery received at high-rate from METEOSAT, ground-based visual and thermal cameras, a Doppler Radar for volcanic-jet monitoring and some ash fallout detectors. Forecasting is using a multi-model approach that is performed every day through a fully automatic procedures for: i) downloading weather forecast data from meteorological mesoscale models; ii) running models of tephra dispersal, iii) plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv) publishing the results on a web-site dedicated to the Civil Protection. Simulations are based on eruptive scenarios obtained by analysing of field data collected from recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring network. The monitoring and forecasting system was tested successfully on some explosive events occurred during 2006 and 2007, and will be tested again during the Volcanic Ash Exercise of ICAO EUR/NAT in November 2009.

  4. Numerical modeling of the three-layered hydrothermal system in the Kuju volcanic region, central Kyushu, Japan

    Science.gov (United States)

    Araragi, K.; Ehara, S.; Fujimitsu, Y.

    2008-12-01

    Numerical modeling of hydrothermal systems beneath active volcanoes has been conducted. Their purposes were, however, confined to interpret individual geothermal systems. We constructed a numerical model of the Kuju volcanic region, central Kyushu, Japan using 3-D finite-difference code HYDROTHERM ver.2.2 (Hayba and Ingebritsen, 1994). The central part of Kuju volcano is categorized as an active magmatic hydrothermal system. Otake-Hatchobaru geothermal area, where two geothermal power plants are in operation, is known as a typical liquid dominated hydrothermal system. These two types of geothermal systems are closely located in the region. Moreover, subsurface horizontal temperature distributions in the Kuju volcanic region consist of a three-layered structure. A horizontal temperature anomaly at a depth of -2000m separates into two anomalies at depths of about 0m. Five anomalies appear in the horizontal temperature distribution of 80m depth. Geothermal systems or such characteristics of the thermal structure should be related to the influence of the magma chamber in the region. Existence of molten magma was suggested from seismic observations (Yoshikawa et al., 2005). Therefore, we presumed that the geothermal systems in Otake- Hatchobaru geothermal area and in the central part of Kuju volcano can be explained by a common magma chamber. We determined the calculation time as 40000 based on the age of the latest large pyroclastic flow deposit (Kamata, 1997). The temperature of the magma chamber in the model was maintained at a constant value during the calculation. Parameter studies of crustal permeabilities were conducted to reproduce temperature profiles obtained by logging at shallow depths (NEDO, 1987). The calculated results show that temperature anomalies in the basement rock seemed to be directly affected by the magma chamber. The results also indicate that molten materials have been continuously supplied from the bottom of the magma chamber of Kuju volcano

  5. Water and gas geochemistry of the Calatrava Volcanic Province (CVP) hydrothermal system (Ciudad Real, central Spain)

    Science.gov (United States)

    Vaselli, Orlando; Nisi, Barbara; Tassi, Franco; Giannini, Luciano; Grandia, Fidel; Darrah, Tom; Capecchiacci, Francesco; del Villar, Pèrez

    2013-04-01

    An extensive geochemical and isotopic investigation was carried out in the water and gas discharges of the Late Miocene-Quaternary Calatrava Volcanic Province (CVP) (Ciudad Real, Spain) with the aim reconstruct the fluid circulation in the area. CVP consists of a series of scattered (monogenetic) vents from where alkaline lava flows and pyroclastic deposits formed in two different periods. The first stage (8.7-6.4 Ma) mainly included ultra-potassic mafic extrusives, whilst the second stage (4.7-1.75 Ma) prevalently originated alkaline and ultra-alkaline volcanics. Both stages were followed by a volcanic activity that extended up to 1.3 and 0.7 Ma, respectively. This area can likely be regarded as one of the most important emitting zones of CO2 in the whole Peninsular Spain along with that of Selva-Emporda in northeastern Spain (Cataluña) and it can be assumed as one of the best examples of natural analogues of CO2 leakages in Spain. This latter aspect is further evidenced by the relatively common water-gas blast events that characterize the CCVF. In the last few years the presence of a CO2-pressurized reservoir at a relatively shallow level as indeed caused several small-sized explosion particularly during the drilling of domestic wells. The fluid discharging sites are apparently aligned along well-defined directions: NW-SE and NNW-SSE and subordinately, ENE-WSW, indicating a clear relationship between the thermal discharges and the volcanic centers that also distribute along these lineaments. The CVP waters are mostly hypothermal (up to 33 °C) and are generally Mg(Ca)-HCO3 in composition and occasionally show relatively high concentrations of Fe and Mn, with pH and electrical conductivity down to 5.5 and up to 6.5 mS/cm, respectively. The oxygen and hydrogen isotopes suggest a meteoric origin for these waters. The mantle source of these volcanic products is apparently preserved in the many CO2-rich (up to 990,000 mmol/mol) gas discharges that characterize CVP

  6. Frequent underwater volcanism in the central Aegean Sea

    Science.gov (United States)

    Huebscher, C.; Ruhnau, M.; Dehghani, G. A.

    2012-04-01

    The extinction of the Minoan culture in the mid second millennium BCE is a well known consequence of the Plinian eruption of Thera volcano (Santorini Island). Santorini is a member of the South Aegean arc forming a chain from the Gulf of Saronikos (Susaki, Egina, Poros, Methana) at West, to an area close to the Anatolian coast at East (Kos, Nisyros and minor islands), through the central part (Milos and Santorini island groups). Underwater volcanic activity was manifested historically only once. During 1649-1650 CE the Kolumbo underwater volcano evolved about 8 km northeast of Santorini. As a consequence of this eruption volcanic ash covered the entire Aegean area and a hazardous tsunami was triggered. Here we show by means of reflection seismic and magnetic data that underwater volcanism occurred more frequently in the central Aegean Sea than previously assumed. Seismic data show that Kolumbo constitutes of five vertically stacked cones of pyroclastic sediment plus at least four smaller cones on the flank of the volcano. The formation of Kolumbo started synchronous with Santorini Island. The entire volume of the Kolumbo pyroclastic cones is estimated to more than 15 cubic-kilometers. Several small-scale cones have been detected in the Anyhdros Basin some km north-east of Kolumbo, being previously interpreted as mud volcanoes by other authors. However, the similarity of seismic and magnetic signatures of these cones and Kolumbo strongly suggest that these cones were also created by underwater volcanism. Volcanic cones, Kolumbo and Santorini are situated along a NE-SW striking graben system that evolved during five extensional tectonic pulses in the Pliocene.

  7. Collaborative studies target volcanic hazards in Central America

    Science.gov (United States)

    Bluth, Gregg J. S.; Rose, William I.

    Central America is the second-most consistently active volcanic zone on Earth, after Indonesia. Centuries of volcanic activity have produced a spectacular landscape of collapsed calderas, debris flows, and thick blankets of pyroclastic materials. Volcanic activity dominates the history, culture, and daily life of Central American countries.January 2002 marked the third consecutive year in which a diverse group of volcanologists and geophysicists conducted focused field studies in Central America. This type of multi-institutional collaboration reflects the growing involvement of a number of U.S. and non-U.S. universities, and of other organizations, in Guatemala and El Salvador (Table 1).

  8. The Satah Mountain and Baldface Mountain volcanic fields: Pleistocene hot spot volcanism in the Anahim Volcanic Belt, west-central British Columbia, Canada

    Science.gov (United States)

    Kuehn, Christian; Guest, Bernard; Russell, James K.; Benowitz, Jeff A.

    2015-03-01

    The Satah Mountain and Baldface Mountain volcanic fields (SMVF, BMVF) comprise more than three dozen small volcanic centers and erosional remnants thereof. These fields are located in the Chilcotin Highland of west-central British Columbia, Canada, and are spatially associated with the Anahim Volcanic Belt (AVB), a linear feature of alkaline to peralkaline plutonic and volcanic centers of Miocene to Holocene ages. The AVB has been postulated to be the track of a hot spot passing beneath the westward moving Cordilleran lithosphere. We test the AVB hot spot model by applying whole-rock 40Ar/39Ar geochronology ( n = 24) and geochemistry. Whole-rock chemical compositions of volcanic rock samples ( n = 59) from these two fields suggest a strong geochemical affinity with the nearby Itcha Range shield volcano; however, SMVF and BMVF centers are mostly small in volume (interaction of the potential hot spot with (pre)existing fracture systems in vicinity of the Itcha Range.

  9. Syn-volcanic cannibalisation of juvenile felsic crust: Superimposed giant 18O-depleted rhyolite systems in the hot and thinned crust of Mesoproterozoic central Australia

    Science.gov (United States)

    Smithies, R. H.; Kirkland, C. L.; Cliff, J. B.; Howard, H. M.; Quentin de Gromard, R.

    2015-08-01

    Eruptions of voluminous 18O-depleted rhyolite provide the best evidence that the extreme conditions required to produce and accumulate huge volumes of felsic magma can occur in the upper 10 km of the crust. Mesoproterozoic bimodal volcanic sequences from the Talbot Sub-basin in central Australia contain possibly the world's most voluminous accumulation of 18O-depleted rhyolite. This volcanic system differs from the better known, but geochemically similar, Miocene Snake River Plain - Yellowstone Plateau of North America. Both systems witnessed 'super' sized eruptions from shallow crustal chambers, and produced 18O-depleted rhyolite. The Talbot system, however, accumulated over a much longer period (>30 Ma), at a single depositional centre, and from a magma with mantle-like isotopic compositions that contrast strongly with the isotopically evolved basement and country-rock compositions. Nevertheless, although the Talbot rhyolites are exclusively 18O-depleted, the unavoidable inference of an 18O-undepleted precursor requires high-temperature rejuvenation of crust in an upper-crustal chamber, and in this respect the evolution of the Talbot rhyolites and 18O-depleted rhyolites of the Snake River Plain - Yellowstone Plateau is very similar. However, instead of older crustal material, the primary upper-crustal source recycled into Talbot rhyolites was comagmatic (or nearly so) felsic rock itself derived from a contemporaneous juvenile basement hot-zone. Whereas giant low δ18O volcanic systems show that voluminous melting of upper crust can occur, our studies indicate that felsic magmas generated at lower crustal depths can also contribute significantly to the thermal and material budget of these systems. The requirement that very high-temperatures be achieved and sustained in the upper crust means that voluminous low δ18O magmatism is rare, primarily restricted to bimodal tholeiitic, high-K rhyolite (A-type) magmatic associations in highly attenuated lithosphere. In the

  10. Geology and geochemistry characteristics of the Chiapanecan Volcanic Arc (Central Area), Chiapas Mexico

    Science.gov (United States)

    Mora, J. C.; Jaimes-Viera, M. C.; Garduño-Monroy, V. H.; Layer, P. W.; Pompa-Mera, V.; Godinez, M. L.

    2007-04-01

    The Chiapanecan Volcanic Arc (CVA), located in the central portion of the State of Chiapas, is a 150 km stretch of volcanoes irregularly aligned in the northwest direction between two great volcanic features: the Trans-Mexican Volcanic Belt to the northwest and the Central American Volcanic Arc to the southeast. The CVA is located in a complex zone marking the interaction of the North American, Caribbean and Cocos plates, near the Motagua-Polochic fault system, the boundary between North American and Caribbean plates. The central part of the CVA is composed of an irregular northwest alignment of at least 10 volcanic structures generally lying along NNW-SSE-trending faults splayed from the Motagua-Polochic system. Among the structures there are seven volcanic domes (Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza and Santotón), one explosion crater (Navenchauc), one collapse structure (Apas), and one dome complex (Tzontehuitz). In the majority of the structures there is a clear resurgence with the formation of several domes in the same structure, with the destruction of previous domes (Navenchauc) or with the formation of new explosion craters or collapse structures (Apas). The volcanic activity in the CVA was mainly effusive accompanied by explosive and phreatomagmatic events and is characterized by volcanic domes accompanied by block-and-ash-flows, ash flows with accretionary lapilli, falls, and pumice flows. The volcanic structures and deposits are calcalkaline in composition with a medium to high content of potassium. CVA volcanic rocks vary from andesite to dacite with SiO 2 between 57 and 66 wt.%, show low concentrations of Ti, P, Nb and Ta, are enriched in Light Rare Earths, depleted in Heavy Rare Earths, and show a small Eu anomaly; all indicative of arc-related volcanism associated with subduction of the Cocos plate under the North American plate, but complicated by the geometry of the plate boundary fault system.

  11. Mineralogical study on volcanic ash of the eruption on September 27, 2014 at Ontake volcano, central Japan: correlation with porphyry copper systems

    Science.gov (United States)

    Minami, Yusuke; Imura, Takumi; Hayashi, Shintaro; Ohba, Tsukasa

    2016-04-01

    The volcanic ash of the eruption on September 27, 2014 at Ontake volcano consists mostly of altered rock fragments. The ash contains partly altered volcanic rock fragments consisting of primary igneous minerals (plagioclase, orthopyroxene, titanomagnetite, and feldspars) and volcanic glass accompanied by alteration minerals to some extents, and contains no juvenile fragments. These features indicate that the eruption was a non-juvenile hydrothermal eruption that was derived from the hydrothermal system developed under the crater. The major minerals derived from hydrothermal alteration zones are silica mineral, kaolin-group mineral, smectite, pyrophyllite, muscovite, alunite, anhydrite, gypsum, pyrite, K-feldspar, albite, and rutile. Minor chlorite, biotite, and garnet are accompanied. Five types of alteration mineral associations are identified from observations on individual ash particles: silica-pyrite, silica-pyrite ± alunite ± kaolin, silica-pyrophyllite-pyrite, silica-muscovite ± chlorite, and silica-K-feldspar ± albite ± garnet ± biotite. The associations indicate development of advanced argillic, sericite, and potassic alteration zones under the crater. Occurrence of anhydrite veinlet and the set of alteration zones indicate hydrothermal alteration zones similar to late-stage porphyry copper systems. Comparing the mineral associations with the geologic model of the late-stage porphyry copper systems, the source depths of mineral associations are estimated to range from near surface to >2 km. The depths of advanced argillic alteration, sericite, and potassic zones are 0 to ~2, ~1.5 to ~2, and >2 km, respectively.

  12. Volcanic processes in the Solar System

    Science.gov (United States)

    Carr, M.H.

    1987-01-01

    This article stresses that terrestrial volcanism represents only part of the range of volcanism in the solar system. Earth processes of volcanicity are dominated by plate tectonics, which does not seem to operate on other planets, except possibly on Venus. Lunar volcanicity is dominated by lava effusion at enormous rates. Mars is similar, with the addition to huge shield volcanoes developed over fixed hotspots. Io, the moon closest to Jupiter, is the most active body in the Solar System and, for example, much sulphur and silicates are emitted. The eruptions of Io are generated by heating caused by tides induced by Jupiter. Europa nearby seems to emit water from fractures and Ganymede is similar. The satellites of Saturn and Uranus are also marked by volcanic craters, but they are of very low temperature melts, possibly of ammonia and water. The volcanism of the solar system is generally more exotic, the greater the distance from Earth. -A.Scarth

  13. Perception of volcanic eruption as agent of change on Merapi volcano, Central Java

    Science.gov (United States)

    Dove, Michael R.

    2008-05-01

    Events like volcanic eruptions challenge equilibrium models of nature. This is a study of the perceptions of eruptions as agents of change, taking Mt. Merapi in Central Java as a case study. Villagers living on Merapi have developed a system of religious belief, and a system of agro-ecological practices, that 'domesticates' the volcanic hazard. The villagers view eruptions as agents of change, often change for the good. The Indonesian government, on the other hand, technologizes and exoticizes the volcanic hazard, and conceptually and materially separates it from the realm of civil society. The state focuses its attention exclusively on intermittent moments of heightened volcanic activity, whereas the villagers focus their attention on the much longer interim periods when there is little or no such activity. This case study shows that not just the perception of risk, but the very concept of risk itself can vary. The cultural production of such concepts co-evolves with natural patterns of perturbation.

  14. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    Energy Technology Data Exchange (ETDEWEB)

    van Soest, M.C.; Kennedy, B.M.; Evans, W.C.; Mariner, R.H.

    2002-04-30

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and CO{sub 2}/{sup 3}He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the contrary, all geochemical evidence suggests that there is a long-lived geothermal system in the Separation Creek area, which has not significantly changed since the early 1990s. There was no archived helium and carbon data, so a definite conclusion regarding the strong mantle signature observed in these tracers cannot yet be drawn. There is a distinct discrepancy between the yearly magma supply required to explain the current uplift (0.006 km{sup 3}/yr) and that required to explain the discharge of CO{sub 2} from the system (0.0005 km{sup 3}/yr). This discrepancy may imply that the chemical signal associated with the increase in magma supply has not reached the surface yet. With respect to this the small changes observed at upper Mesa Creek require further attention, due to the recent volcanic vent in that area it may be the location were the chemical signal related to the uplift can most quickly reach the surface. Occurrence of such strong mantle signals in cold/diffuse geothermal systems suggests that these systems should not be ignored during volcano monitoring or geothermal evaluation studies. Although the surface-expression of these springs in terms of heat is minimal, the chemistry carries important information concerning the size and nature of the underlying high-temperature system and any changes taking place in it.

  15. Quaternary volcanism in the Acambay graben, Mexican Volcanic Belt: Re-evaluation for potential volcanic danger in central Mexico

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Pedrazzi, D.; Lacan, P.; Roldan-Quintana, J.; Ortuňo, M.; Zuniga, R. R.; Laurence, A.

    2015-12-01

    The Mexican Volcanic Belt (MVB) is best known for the major active stratovolcanoes, such as Popocatépetl, Citlaltépetl and Colima. The most common stratovolcanoes in this province are modest-size cones with heights of 800 to 1000 m. Examples are Tequila, Sangangüey, Las Navajas, Culiacán, La Joya, El Zamorano, Temascalcingo and Altamirano; these last two were formed within the Acambay Graben in central MVB. The Acambay graben (20 x 70 km) is 100 km to the NW of Mexico City, with E-W trending seismically active normal faults; in particular the Acambay-Tixmadejé fault related to a mB =7 earthquake in 1912. Within the graben there are many volcanic structures, including calderas, domes, cinder cones and stratovolcanoes; Temascalcingo and Altamirano are the largest, with about 800 and 900 m heights, respectively. Temascalcingo is mostly composed of dacitic lavas and block and ash flow deposits. Includes a 3 x 2.5 km summit caldera and a magmatic sector collapse event with the associated debris avalanche deposit. 14C ages of 37-12 ka correspond to the volcano's latest phases that produced pyroclastic deposits. A major plinian eruption formed the San Mateo Pumice with an age of <20 Ka. Altamirano volcano is poorly studied; it is andesitic-dacitic, composed of lavas, pyroclastic flow deposits, and pumice fallouts. Morphologically is better preserved than Temascalcingo, and it should be younger. 14C ages of 4.0-2.5 ka were performed in charcoal within pyroclastic flow deposits that apparently were erupted from Altamirano. An undated 3 m thick pumice fallout on the flanks of Altamirano volcano could be also Holocene. It represents a major explosive event. The relatively young ages found in volcanic deposits within the Acambay graben raise the volcanic danger level in this area, originally thought as an inactive volcanic zone. The two major volcanoes, Temascalcingo and Altamirano, should be considered as dormant volcanoes that could restart activity at any time. We

  16. Resistivity structure of the central Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Risk, G. F.; Bibby, H. M.; Caldwell, T. G.

    1999-06-01

    The Taupo Fault Belt (TFB) is a 15-km-wide zone of active normal faulting, which is located in the central portion of the Taupo Volcanic Zone (TVZ), New Zealand, and is aligned sub-parallel to the strike of this zone. A large-scale multiple-source bipole-dipole resistivity survey has shown that the TFB is characterised by high resistivity (ca. 250 Ωm) to depths of ca. 7 km, in contrast to the adjacent regions in the east and west of the TVZ where resistivities are much lower (TFB is marked by the Paeroa fault. East of the fault, the Taupo-Reporoa depression is filled with volcaniclastic rocks that have low resistivities believed to be caused by the presence of clay alteration. At the Paeroa fault, the conductive volcaniclastics are downthrown to the west by about 1 km but they can be traced no more than 2.5 km west into the TFB. To the west of the TFB, a low-resistivity layer about 500 m deep has been identified as a sequence of older (>1 Ma) ignimbrites that have undergone slow diagenetic alteration that has produced clay minerals. The volcaniclastics in the TFB have high resistivities which suggests that they have not undergone significant alteration and are thus younger than the volcaniclastics in the regions to both east and west. These high resistivities are also consistent with the absence of surface geothermal activity and low heat flow. The TFB also exhibits high seismicity and active faulting in contrast with its surrounding. It was not possible to determine the depth to basement rocks in the TFB because of the lack of resistivity contrast between the basement and the overlying volcanics, but gravity data indicate that the young volcanics are no more than 3 km thick.

  17. Detailed Seismic Reflection Images of the Central American Volcanic Arc

    Science.gov (United States)

    McIntosh, K. D.; Fulthorpe, C. S.

    2005-12-01

    New high-resolution seismic reflection profiles across the Central American volcanic arc (CAVA) reveal an asymmetric deformation pattern with large-scale folding and uplift of basinal strata in the forearc contrasted by intrusive bodies, normal faults, and possible strikes-slip faults in the backarc. Since Miocene times the CAVA has migrated seaward, apparently impinging on the Sandino forearc basin and creating or modifying the low-lying Nicaragua depression, which contains the backarc and much of the arc. However the structural nature of the depression and its possible relationship to forearc sliver movement is poorly known. In November-December 2004 we recorded a large, high-resolution, seismic reflection dataset largely on the Pacific shelf (forearc) area of Central America, extending from NW Costa Rica to the SE edge of El Salvador's territorial waters. We seized an opportunity to study the nature of the CAVA by recording data into the Gulf of Fonseca, a large embayment at the intersection of Nicaragua, Honduras, and El Salvador. With 3 GI airguns and a 2100 m streamer we recorded data with typical penetration of 2-3 seconds in the Sandino basin and frequency content of ~10-250 Hz (at shallow levels). Penetration was limited over the arc summit with high velocity volcanic rocks encountered at depths as shallow as a few hundred meters. To the NE the edge of the Nicaragua depression occurs abruptly; our data show a well-developed sedimentary basin 1.5-3 km thick separated by numerous steeply-dipping faults. The broadband signal and good penetration of this dataset will help us determine the chronology of arc development in this position and the styles of deformation in the forearc, arc, and backarc areas. In turn, this will help us understand the regional tectonic and stratigraphic development of this margin due to the profound affects of the arc.

  18. Evidences for a volcanic province in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Sudhakar, M.

    Based on various lines of evidence such as the widespread occurrence of basalts, pumice, volcanic glass shards and their transformational products (zeolites, palagonites, and smectite-rich sediments), we suggest the presence of a volcanic province...

  19. SURFACE AREA AND MICRO-ROUGHNESS OF VOLCANIC ASH PARTICLES: A case study, Acigol Volcanic Complex, Cappadocia, Central Turkiye

    Science.gov (United States)

    Ersoy, O.; Aydar, E.; Sen, E.; Atici, G.

    2009-04-01

    Every single ash particle may convey information about its own formation environment and conditions. Certain features on particles may give a hint about the fragmentation regime, the intensity of fragmentation and quantity of water that partakes in the fragmentation process, etc. On this account, this study majored in the analysis on finer pyroclastic material, namely volcanic ash particles. Here, we used volcanic ash particles from Quaternary Acigol Volcanic complex (West of Nevsehir, Cappadocia, Central Turkiye). Quaternary Acigol Volcanic complex lies between the towns of Nevsehir and Acigol. It consists of a shallow caldera, a thick pyroclastic apron, seven obsidian dome clusters, and scattered cinder cones and associated lavas (Druitt et al., 1995). The products of explosive volcanism of the region were distinguished as two main Quaternary tuffs by a recent study (Druitt et al., 1995). Samples are from ashfall beds in a sequence of intercalated pumice fall, ashfall, and ignimbrite beds. In this study in order to achieve surface properties of volcanic ash particles, surface areas and micro-roughness of ash particles were measured on digital elevation models (DEM) reconstructed from stereoscopic images acquired on Scanning Electron Microscope (SEM) at varying specimen tilt angles. Correlation between surface texture of volcanic ash particles and eruption characteristics was determined.

  20. Landscape evolution within a retreating volcanic arc, Costa Rica, Central America

    Science.gov (United States)

    Marshall, Jeffrey S.; Idleman, Bruce D.; Gardner, Thomas W.; Fisher, Donald M.

    2003-05-01

    Subduction of hotspot-thickened seafloor profoundly affects convergent margin tectonics, strongly affecting upper plate structure, volcanism, and landscape evolution. In southern Central America, low-angle subduction of the Cocos Ridge and seamount domain largely controls landscape evolution in the volcanic arc. Field mapping, stratigraphic correlation, and 40Ar/39Ar geochronology for late Cenozoic volcanic rocks of central Costa Rica provide new insights into the geomorphic response of volcanic arc landscapes to changes in subduction parameters (slab thickness, roughness, dip). Late Neogene volcanism was focused primarily along the now-extinct Cordillera de Aguacate. Quaternary migration of the magmatic front shifted volcanism northeastward to the Caribbean slope, creating a new topographic divide and forming the Valle Central basin. Stream capture across the paleo Aguacate divide led to drainage reversal toward the Pacific slope and deep incision of reorganized fluvial networks. Pleistocene caldera activity generated silicic ash flows that buried the Valle Central and descended the Tárcoles gorge to the Orotina debris fan at the coast. Growth of the modern Cordillera Central accentuated relief along the new divide, establishing the Valle Central as a Pacific slope drainage basin. Arc migration, relocation of the Pacific-Caribbean drainage divide, and formation of the Valle Central basin resulted from slab shallowing as irregular, hotspot-thickened crust entered the subduction zone. The geomorphic evolution of volcanic arc landscapes is thus highly sensitive to changes in subducting plate character.

  1. Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

    2008-10-01

    We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

  2. Gravity study of the Central African Rift system: a model of continental disruption 2. The Darfur domal uplift and associated Cainozoic volcanism

    Science.gov (United States)

    Bermingham, P. M.; Fairhead, J. D.; Stuart, G. W.

    1983-05-01

    Gravity studies of the Darfur uplift, Western Sudan, show it to be associated with a circular negative Bouguer anomaly, 50 mGal in amplitude and 700 km across. A three-dimensional model interpretation of the Darfur anomaly, using constraints deduced from geophysical studies of similar but more evolved Kenya and Ethiopia domes, suggests either a low-density laccolithic body at mid-lithospheric depth (~ 60 km) or a thinned lithosphere with emplacement at high level of low-density asthenospheric material. The regional setting of the Darfur uplift is described in terms of it being an integral part of the Central African Rift System which is shown to be broadly equivalent to the early to middle Miocene stage in the development of the Afro-Arabian Rift System. Comparisons between these rift systems suggest that extensional tectonics and passive rifting, resulting in the subsiding sedimentary rift basins associated with the Ngaoundere, Abu Gabra, Red Sea and Gulf of Aden rifts, are more typical of the early stage development of passive continental margins than the active domal uplift and development of rifted features associated with the Darfur, Kenya and Ethiopia domes.

  3. Investigation of polymetallic mineralisation in Lower Devonian volcanics near Alva, central Scotland

    OpenAIRE

    Hall, I H S; Gallagher, M J; Skilton, B.R.H.; C. E. Johnson

    1982-01-01

    The subsurface characteristics of three known occurrences of fracture-controlled mineralisation in the Lower Devonian Ochil Volcanic Formation near Alva, central Scotland, were tested by shallow boreholes. Target structures were intersected by each borehole, but they contain only minor amounts of baryte and geochemical enrichments of copper, arsenic and uranium. Differential fracturing within the variegated volcanic sequence and enhanced brecciation at fault interse...

  4. Palaeoenvironment reconstruction, volcanic evolution and geochronology of the Cerro Blanco subcomplex, Nevados de Chillan volcanic complex, Central Chile

    OpenAIRE

    Mee, Katy; Gilbert, Jennie S.; McGarvie, David W.; Naranjo, Jose A.; Pringle, Malcolm S.

    2009-01-01

    Nevados de Chillán Volcanic Complex, central Chile, has been active for at least 640 ka—a period spanning a number of glacial and interglacial periods. Geologic mapping, radiometric dating and geochemical analysis have identified six new volcanic units and produced four new 40Ar/39Ar ages for Cerro Blanco, the northern subcomplex of Nevados de Chillán volcano. Compositions range from dacite to basaltic-andesite and a new geologic map is presented. Examination of lava fracture structures on bo...

  5. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    KAUST Repository

    Ruch, Joel

    2016-01-23

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic and structural field data along the strike-slip Central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion; consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activity steadily migrated eastward and currently focus on a 10 km long x 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter-term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the Central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  6. Magmatic control along a strike-slip volcanic arc: The central Aeolian arc (Italy)

    Science.gov (United States)

    Ruch, J.; Vezzoli, L.; De Rosa, R.; Di Lorenzo, R.; Acocella, V.

    2016-02-01

    The regional stress field in volcanic areas may be overprinted by that produced by magmatic activity, promoting volcanism and faulting. In particular, in strike-slip settings, the definition of the relationships between the regional stress field and magmatic activity remains elusive. To better understand these relationships, we collected stratigraphic, volcanic, and structural field data along the strike-slip central Aeolian arc (Italy): here the islands of Lipari and Vulcano separate the extensional portion of the arc (to the east) from the contractional one (to the west). We collected >500 measurements of faults, extension fractures, and dikes at 40 sites. Most structures are NNE-SSW to NNW-SSE oriented, eastward dipping, and show almost pure dip-slip motion, consistent with an E-W extension direction, with minor dextral and sinistral shear. Our data highlight six eruptive periods during the last 55 ka, which allow considering both islands as a single magmatic system, in which tectonic and magmatic activities steadily migrated eastward and currently focus on a 10 km long × 2 km wide active segment. Faulting appears to mostly occur in temporal and spatial relation with magmatic events, supporting that most of the observable deformation derives from transient magmatic activity (shorter term, days to months), rather than from steady longer-term regional tectonics (102-104 years). More in general, the central Aeolian case shows how magmatic activity may affect the structure and evolution of volcanic arcs, overprinting any strike-slip motion with magma-induced extension at the surface.

  7. Synthesis of morphotectonics and volcanics of the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Mukherjee, A.D.; Iyer, S.D.

    The Central Indian Ocean Basin (CIOB) is an enigmatic ocean basin in the young and tectonically complex Indian Ocean. Major tectonic and volcanic forms identified are fracture zones, abyssal hills, seamounts and ridges and a unique zone...

  8. The geochemical variations of the upper cenozoic volcanism along the Calama Olacapato El Toro transversal fault system in central Andes (˜24°S): petrogenetic and geodynamic implications

    Science.gov (United States)

    Matteini, M.; Mazzuoli, R.; Omarini, R.; Cas, R.; Maas, R.

    2002-02-01

    In this paper, we present new geochemical and Sr-Nd isotopic data for several Upper Miocene volcanic centres aligned along one of the most extensive transcurrent lineament in the Central Andes, the Calama-Olacapato-El Toro (COT). The transversal volcanic belt along COT is constituted by large composite volcanoes and a caldera structure; they are, from NW to SE, Puntas Negras, Rincon, Tul Tul, Del Medio and Pocitos (TUMEPO), Quevar Aguas Calientes and Tastil. In order to compare chemical data from the different centres along the COT transect, differentiation effects were minimised by using data extrapolated at 60% SiO2 with least-square regression method. In the western sector of the COT, the volcanic products of Puntas Negras and Rincon show relatively high K2O and 87Sr/86Sr and low Rb/Cs, Ta/Th, La/Yb, 143Nd/144Nd. To the east, the TUMEPO products have high Sr and 143Nd/144Nd, La/Yb and Ba/Rb and low Y, 87Sr/86Sr. In the easternmost COT sector, Quevar, Aguas Calientes and Tastil volcanic complexes exhibit low La/Yb, high87Sr/Sr86 and low 143Nd/144Nd. On the basis of these data, we propose a petrogenetic and geodynamical model for Central Andes at 24°S. In correspondence of Miocene-Quaternary volcanic arc (Puntas Negras and Rincon), the magmas inherited a calcalkaline signature partly modified by upper crustal and/or sediment assimilation. In the central eastern sector, melting, assimilation, storage and homogenisation (MASH) processes occurred at the base of a thickened crust. In this COT sector, TUMEPO products show an evident lower crust signature and could be considered representative for MASH derived magmas. In the easternmost sector, Quevar, Aguas Calientes and Tastil products could represent magmas generated by partial melting of underthrusted Brasilian shield and mixed with magmas derived by MASH processes.

  9. Dating of the late Quaternary volcanic events using Uranium-series technique on travertine deposit: A case study in Ihlara, Central Anatolia Volcanic Province

    Science.gov (United States)

    Karabacak, Volkan; Tonguç Uysal, İ.; Ünal-İmer, Ezgi

    2016-04-01

    Dating of late Quaternary volcanism is crucial to understanding of the recent mechanism of crustal deformation and future volcanic explosivity risk of the region. However, radiometric dating of volcanic products has been a major challenge because of high methodological error rate. In most cases, there are difficulties on discrimination of the volcanic lava flow relations in the field. Furthermore, there would be unrecorded and unpreserved volcanoclastic layers by depositional and erosional processes. We present a new method that allows precise dating of late Quaternary volcanic events (in the time range of 0-500,000 years before present) using the Uranium-series technique on travertine mass, which is thought to be controlled by the young volcanism. Since the high pressure CO2 in the spring waters are mobilized during crustal strain cycles and the carbonates are precipitated in the fissures act as conduit for hot springs, thus, travertine deposits provide important information about crustal deformation. In this study we studied Ihlara fissure ridge travertines in the Central Anatolia Volcanic Province. This region is surrounded by many eruption centers (i.e. Hasandaǧı, Acıgöl and Göllüdaǧı) known as the late Quaternary and their widespread volcanoclastic products. Recent studies have suggested at least 11 events at around Acıgöl Caldera for the last 180 ka and 2 events at Hasandaǧı Stratovolcano for the last 30 ka. Active travertine masses around Ihlara deposited from hotwaters, which rise up through deep-penetrated fissures in volcanoclastic products of surrounding volcanoes. Analyses of the joint systems indicate that these vein structures are controlled by the crustal deformation due to young volcanism in the vicinity. Thus, the geological history of Ihlara travertine mass is regarded as a record of surrounding young volcanism. We dated 9 samples from 5 ridge-type travertine masses around Ihlara region. The age distribution indicates that the crustal

  10. Le volcanisme cambrien du Maroc central : implications géodynamiquesThe Central Morocco Cambrian volcanism: geodynamic implications

    Science.gov (United States)

    Ouali, Houssa; Briand, Bernard; Bouchardon, Jean-Luc; Capiez, Paul

    2003-05-01

    In southeastern Central Morocco, the Bou-Acila volcanic complex is considered of Cambrian age. In spite of low-grade metamorphic effect, initial volcanic texture and mineralogy can be recognized and volcanic rocks are dominated by dolerites and porphyric dolerites. The initial mineralogy is composed of plagioclases, pyroxenes and dark minerals. A secondary mineral assemblage is composed of albite, epidote, chlorite and calcite. According to their immobile elements compositions, the southeastern central Morocco metavolcanites are of within-plate continental tholeiites. This volcanism and those recognized in many other areas in Morocco confirm a Cambrian extensive episode within the Gondwana supercontinent. To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).

  11. Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia

    2014-05-01

    In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

  12. Geologic map of the Simcoe Mountains Volcanic Field, main central segment, Yakama Nation, Washington

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2015-01-01

    Mountainous parts of the Yakama Nation lands in south-central Washington are mostly covered by basaltic lava flows and cinder cones that make up the Simcoe Mountains volcanic field. The accompanying geologic map of the central part of the volcanic field has been produced by the U.S. Geological Survey (USGS) on behalf of the Water Resources Program of the Yakama Nation. The volcanic terrain stretches continuously from Mount Adams eastward as far as Satus Pass and Mill Creek Guard Station. Most of the many hills and buttes are volcanic cones where cinders and spatter piled up around erupting vents while lava flows spread downslope. All of these small volcanoes are now extinct, and, even during their active lifetimes, most of them erupted for no more than a few years. On the Yakama Nation lands, the only large long-lived volcano capable of erupting again in the future is Mount Adams, on the western boundary.

  13. An InSAR-based survey of volcanic deformation in the central Andes

    OpenAIRE

    M. E. Pritchard; Simons, M.

    2004-01-01

    We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°–27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); a...

  14. Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America

    Directory of Open Access Journals (Sweden)

    D. Loyola

    2008-01-01

    Full Text Available Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash into the atmosphere, as well as several gases, including sulphur dioxide (SO2. These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

  15. Geology and Geochronology of the Central Part of Chiapanecan Volcanic Arc, Mexico.

    Science.gov (United States)

    Layer, P. W.

    2006-12-01

    The Chiapanecan Volcanic Arc (CVA) is a 150 km stretch of volcanoes irregularly aligned in a northwest direction, including El Chichón volcano located in the central portion of the State of Chiapas, southern Mexico. It lies between two great volcanic features: the Trans-Mexican Volcanic Arc to the northwest, and the Central American Volcanic Arc to the southeast, in a complex zone of the interaction of the North American, Caribbean and Cocos Plates. The central part of the CVA is composed of an irregular northwest alignment of at least 12 volcanic structures located 80 km to the southeast of El Chichón (the only currently active volcano in the CVA). These structures include one explosion crater (Navenchauc), one collapse structure (Apas), one dome complex (Tzontehuitz) and nine volcanic domes (Navenchauc, Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza, Miguel Hidalgo and Santotón) with associated pyroclastic flow deposits. The juvenile lithics from these deposits have a porphyritic texture with phenocrysts of plagioclase (±), amphibole (±), clinopyroxene (±), orthopyroxene (±) and Fe-Ti oxides surrounded by a matrix composed by microlites of plagioclase and glass. The chemical results obtained from representative samples from the deposits and structures indicate that these belong to the series of subalkaline rocks, and fall into the calcalkaline field with medium to high contents of potassium. They vary in their composition from andesite to dacite with an interval of silica between a 56 to a 66% (wt.). The ages reported in the literature and obtained in this study by means of the K-Ar and the 40Ar/39Ar methods, respectively, indicated that volcanism was episodic and spanned a time from 2100 ky ago (Tzontehuitz) to 225 ky ago (Venustiano Carranza).

  16. Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua

    Science.gov (United States)

    Pearson, S.C.P.; Connor, C.B.; Sanford, W.E.

    2008-01-01

    Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured in a low-temperature fumarole field located 3.5 km down the flanks of the volcano. Analysis of these time series reveals that they respond extremely rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. These rapid temperature changes are caused by increased flow of water vapor through flank fumaroles during volcanism. The soil temperature response, ~5 °C, is repetitive and complex, with as many as 13 pulses during a single volcanic episode. Analysis of the frequency spectrum of these temperature time series shows that these anomalies are characterized by broad frequency content during volcanic activity. They are thus easily distinguished from seasonal trends, diurnal variations, or individual rainfall events, which triggered rapid transient increases in temperature during 5% of events. We suggest that the mechanism responsible for the distinctive temperature signals is rapid change in pore pressure in response to magmatism, a response that can be enhanced by meteoric water infiltration. Monitoring of distal fumaroles can therefore provide insight into coupled volcanic-hydrologic-meteorologic systems, and has potential as an inexpensive monitoring tool.

  17. Central nervous system

    Science.gov (United States)

    The central nervous system is composed of the brain and spinal cord. Your brain and spinal cord serve as the main "processing center" for your entire nervous system. They control all the workings of your body.

  18. Transient magmatic control in a tectonic domain: the central Aeolian volcanic arc (South Italy)

    KAUST Repository

    Ruch, Joel

    2015-04-01

    The background stress field in volcanic areas may be overprinted by that produced by transient magmatic intrusions, generating local faulting. These events are rarely monitored and thus not fully understood, generating debate about the role of magma and tectonics in any geodynamic setting. Here we carried out a field structural analysis on the NNW-SSE strike-slip system of the central Aeolian Arc, Italy (Lipari and Vulcano islands) with ages constrained by stratigraphy to better capture the tectonic and magmatic evolution at the local and regional scales. We consider both islands as a single magmatic system and define 5 principal stratigraphic units based on magmatic and tectonic activity. We collected >500 measurements of faults, extension fractures and dikes at 40 sites, mostly NNE-SSW to NNW-SSE oriented with a dominant NS orientation. These structures are governed quasi exclusively by pure dip-slip motion, consistent with an E-W extension direction, with minor dextral and sinistral slip, the latter being mostly related to old deposits (>50 ka). We further reconstructed the evolution of the Vulcano-Lipari system during the last ~20 ka and find that it consists of an overall half-graben-like structure, with faults with predominant eastward dips. Field evidence suggests that faulting occurs often in temporal and spatial relation with magmatic events, suggesting that most of the observable deformation derived from transient magmatic activity, rather than from steady regional tectonics. To explain the dominant magmatic and episodic extension in a tectonic dominant domain, we propose a model where the regional N-S trending maximum horizontal stress, responsible for strike-slip activity, locally rotates to vertical in response to transient pressurization of the magmatic system and magma rise below Lipari and Vulcano. This has possibly generated the propagation of N-S trending dikes in the past 1 ka along a 10 km long by 1 km wide crustal corridor, with important

  19. Investigation of strontium sorption onto Kula volcanics using Central Composite Design

    Energy Technology Data Exchange (ETDEWEB)

    Kuetahyal Latin-Small-Letter-Dotless-I , Ceren, E-mail: ceren.kutahyali@ege.edu.tr [Ege University, Institute of Nuclear Sciences, 35100 Bornova, Izmir (Turkey); Cetinkaya, Berkan; Acar, M. Bahad Latin-Small-Letter-Dotless-I r [Ege University, Institute of Nuclear Sciences, 35100 Bornova, Izmir (Turkey); Is Latin-Small-Letter-Dotless-I k, Nuray Olcay [Ege University, Engineering Faculty, Leather Engineering Department, 35100 Bornova, Izmir (Turkey); Cireli, Irfan [Celal Bayar University Kula Leather Training School, 45170 Manisa (Turkey)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer We model strontium sorption on non-treated and HCl-treated Kula volcanics to obtain data on the radionuclide migration. Black-Right-Pointing-Pointer Central Composite Design was used in the experiments avoiding the traditional 'one-factor-at-a-time' experiments. Black-Right-Pointing-Pointer The results show that the K{sub d} values are higher at pH 7-9 which is the pH range of the natural waters. - Abstract: In performance assessment studies, the uptake of the radioactive elements by rock formations play an important role in retarding their aqueous phase migration. Sorption studies of radionuclides have been conducted to obtain data on the distribution coefficient (K{sub d}) that is as an input parameter in the performance assessment of the geological disposal of radioactive wastes. In this work, sorption experiments were studied in a batch sorption system using Sr(NO{sub 3}){sub 2} solution on non-treated and HCl-treated Kula volcanics. The distribution coefficient (K{sub d}) values of Sr{sup 2+} derived from batch experiments were used to evaluate the migration behavior of Sr{sup 2+}. Central Composite Design was used in the experiments. Sr sorption was studied as a function of pH, temperature, initial concentration of adsorbate and contact time. The results show that the K{sub d} values are higher at pH 7-9 which is the pH range of the natural waters. The kinetic data conformed better to the pseudo-second-order equation. Thermodynamic parameters {Delta}H Degree-Sign , {Delta}S Degree-Sign and {Delta}G Degree-Sign were estimated and these parameters show that adsorption is endothermic. The correlation coefficients indicate that the Langmuir model fits better for the strontium sorption onto non-treated and HCl-treated Kula volcanics with monolayer capacities as 2.04 and 1.72 mg/g, respectively.

  20. A multidisciplinary system for monitoring and forecasting Etna volcanic plumes

    Science.gov (United States)

    Coltelli, Mauro; Prestifilippo, Michele; Spata, Gaetano; Scollo, Simona; Andronico, Daniele

    2010-05-01

    One of the most active volcanoes in the world is Mt. Etna, in Italy, characterized by frequent explosive activity from the central craters and from fractures opened along the volcano flanks which, during the last years, caused several damages to aviation and forced the closure of the Catania International Airport. To give precise warning to the aviation authorities and air traffic controller and to assist the work of VAACs, a novel system for monitoring and forecasting Etna volcanic plumes, was developed at the Istituto Nazionale di Geofisica e Vulcanologia, sezione di Catania, the managing institution for the surveillance of Etna volcano. Monitoring is carried out using multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation geosynchronous satellite able to track the volcanic plume with a high time resolution, visual and thermal cameras used to monitor the explosive activity, three continuous wave X-band disdrometers which detect ash dispersal and fallout, sounding balloons used to evaluate the atmospheric fields, and finally field data collected after the end of the eruptive event needed to extrapolate important features of explosive activity. Forecasting is carried out daily using automatic procedures which download weather forecast data obtained by meteorological mesoscale models from the Italian Air Force national Meteorological Office and from the hydrometeorological service of ARPA-SIM; run four different tephra dispersal models using input parameters obtained by the analysis of the deposits collected after few hours since the eruptive event similar to 22 July 1998, 21-24 July 2001 and 2002-03 Etna eruptions; plot hazard maps on ground and in air and finally publish them on a web-site dedicated to the Italian Civil Protection. The system has been already tested successfully during several explosive events occurring at Etna in 2006, 2007 and 2008. These events produced eruption

  1. Central nervous system resuscitation

    DEFF Research Database (Denmark)

    McIntosh, T K; Garde, E; Saatman, K E;

    1997-01-01

    Traumatic injury to the central nervous system induces delayed neuronal death, which may be mediated by acute and chronic neurochemical changes. Experimental identification of these injury mechanisms and elucidation of the neurochemical cascade following trauma may provide enhanced opportunities...

  2. The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

    2014-05-01

    The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

  3. Evidence of recent deep magmatic activity at Cerro Bravo-Cerro Machín volcanic complex, central Colombia. Implications for future volcanic activity at Nevado del Ruiz, Cerro Machín and other volcanoes

    Science.gov (United States)

    Londono, John Makario

    2016-09-01

    In the last nine years (2007-2015), the Cerro Bravo-Cerro Machín volcanic complex (CBCMVC), located in central Colombia, has experienced many changes in volcanic activity. In particular at Nevado del Ruiz volcano (NRV), Cerro Machin volcano (CMV) and Cerro Bravo (CBV) volcano. The recent activity of NRV, as well as increasing seismic activity at other volcanic centers of the CBCMVC, were preceded by notable changes in various geophysical and geochemical parameters, that suggests renewed magmatic activity is occurring at the volcanic complex. The onset of this activity started with seismicity located west of the volcanic complex, followed by seismicity at CBV and CMV. Later in 2010, strong seismicity was observed at NRV, with two small eruptions in 2012. After that, seismicity has been observed intermittently at other volcanic centers such as Santa Isabel, Cerro España, Paramillo de Santa Rosa, Quindío and Tolima volcanoes, which persists until today. Local deformation was observed from 2007 at NRV, followed by possible regional deformation at various volcanic centers between 2011 and 2013. In 2008, an increase in CO2 and Radon in soil was observed at CBV, followed by a change in helium isotopes at CMV between 2009 and 2011. Moreover, SO2 showed an increase from 2010 at NRV, with values remaining high until the present. These observations suggest that renewed magmatic activity is currently occurring at CBCMVC. NRV shows changes in its activity that may be related to this new magmatic activity. NRV is currently exhibiting the most activity of any volcano in the CBCMVC, which may be due to it being the only open volcanic system at this time. This suggests that over the coming years, there is a high probability of new unrest or an increase in volcanic activity of other volcanoes of the CBCMVC.

  4. Modeling volcanic ash resuspension – application to the 14–18 October 2011 outbreak episode in Central Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    A. Folch

    2013-09-01

    Full Text Available Volcanic fallout deposits from the June 2011 Cordón Caulle eruption in Central Patagonia were remobilized in several occasions months after their emplacement. In particular, during 14–18 October 2011, an intense outbreak episode generated huge volcanic clouds that were dispersed across Argentina, causing multiple impacts in the environment, affecting the air quality and disrupting airports. Fine ash particles in volcanic fallout deposits can be resuspended under favourable meteorological conditions, particularly during strong wind episodes in arid environments having low soil moisture and poor vegetation coverage. In opposition to eruption-formed ash clouds, modeling of resuspension-formed ash clouds has received little attention. In consequence, there are no emission schemes specially developed and calibrated for volcanic ash, and no operational product exists to model and forecast the formation and dispersal of resuspension ash clouds. Here we implement three dust emission schemes of increasing complexity in the FALL3D tephra dispersal model and use the 14–18 October 2011 outbreak episode as a model test case. We calibrate the emission schemes and validate the results of the coupled WRF-ARW/FALL3D modeling system using satellite imagery and measurements of visibility (a quantity related to total suspended particle concentration at surface and particulate matter (PM10 concentration at several meteorological and air quality stations sparse across Argentina and Uruguay. Our final goal is to test the capability of the modeling system to become, in the near future, an operational forecast product for volcanic ash resuspension events.

  5. Characterization, functioning and classification of two volcanic soil profiles under different land uses in Central Mexico

    OpenAIRE

    Prado, B.; Duwig, Céline; Hidalgo, C; Gomez, D.; Yee, H.; Prat, Christian; Esteves, Michel; Etchevers, J.D.

    2007-01-01

    Volcanic soils constitute an important resource for agriculture and forestry in Central Mexico, as well as in various world regions. They exhibit unique properties and high productive potential related to the amorphous materials they contain. The relationship between amorphous materials, soil characteristic and functioning, has not been well studied. The objectives of the present work were to assess the influence of land use (agricultural and forest), topography and other soil forming factors...

  6. Magnetic fabric of ignimbrites : a case study from the central Anatolian volcanic province

    OpenAIRE

    Agro, A; Zanella, A; Le Pennec, Jean-Luc; Temel, A.

    2015-01-01

    The magnetic fabric of the Pliocene Kızılkaya ignimbrite in the Central Anatolian Volcanic Province has been investigated by anisotropy of magnetic susceptibility (AMS) and isothermal remanent magnetization (AIRM). Seven sections were sampled at various stratigraphic heights within the devitrified portion of the ignimbrite. The magnetic mineralogy is complex: titanomagnetite occurs as magmatic grains, and as inclusions in other phenocryst and glass shards; an oxidized phase and hema...

  7. FNAL central email systems

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Jack; Lilianstrom, Al; Pasetes, Ray; Hill, Kevin; /Fermilab

    2004-10-01

    The FNAL Email System is the primary point of entry for email destined for an employee or user at Fermilab. This centrally supported system is designed for reliability and availability. It uses multiple layers of protection to help ensure that: (1) SPAM messages are tagged properly; (2) All mail is inspected for viruses; and (3) Valid mail gets delivered. This system employs numerous redundant subsystems to accomplish these tasks.

  8. Geochemical Characteristics of the Cenozoic Volcanic Rocks in Central Qiangtang, Tibet: Relation with the Uplift of the Qinghai Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    TAN Fuwen; PAN Guitang; XU Qiang

    2001-01-01

    The Cenozoic volcanic rocks in central Qiangtang are tectonically outcropped in the transitional area where crust of the Qinghai-Tibet Plateau thins northwards and the Passion's ratios of the crust increases abnormally northwards. Of all Cenozoic volcanic rocks of northern Tibet, the volcanic rocks in Qiangtang area is the oldest one with ages from 44.1±1.0 Ma to 32.6±0.8 Ma. Petrological and geochemical studies of the volcanic rocks in central Qiangtang suggest they formed in the extension environment of post collision-orogeny and were the product of mixture of magmas from crust and mantle. The uplift of the northern plateau is closely related to decoupling of mantle lithosphere,crustal extension and thinning as well as volcanism. Therefore, it is inferred that the main uplift of the northern plateau began from about 40 Ma ago.

  9. Magnetotelluric Studies of the Laguna del Maule Volcanic Field, Central Chile

    Science.gov (United States)

    Cordell, D. R.; Unsworth, M. J.; Diaz, D.; Pavez, M.; Blanco, B.

    2015-12-01

    Geodetic data has shown that the surface of the Laguna del Maule (LdM) volcanic field in central Chile has been moving upwards at rates >20 cm/yr since 2007 over a 200 km2 area. It has been hypothesized that this ground deformation is due to the inflation of a magma body at ~5 km depth beneath the lake (2.8 km b.s.l.). This magma body is a likely source for the large number of rhyolitic eruptions at this location over the last 25 ka. A dense broadband magnetotelluric (MT) array was collected from 2009 to 2015 and included data from a geothermal exploration project. MT phase tensor analysis indicates that the resistivity structure of the region is largely three-dimensional for signals with periods longer than 1 s, which corresponds to depths >5 km. The MT data were inverted using the ModEM inversion algorithm to produce a three-dimensional electrical resistivity model which included topography. Four primary features were identified in the model: 1) A north-south striking, 10 km by 5 km, low-resistivity zone (inflation centre at a depth of ~5 km (2.8 km b.s.l.) is interpreted as a zone of partial melt which may be supplying material via conduits to account for the observed ground deformation; 2) A shallow low-resistivity feature ~400 m beneath the lake surface (1.8 km a.s.l.) and spatially coincident with the inflation centre is interpreted to be a zone of hydrothermal alteration; 3) A thin, low-resistivity feature to the west of LdM at a depth of ~250 m (2.2 km a.s.l.) is interpreted to be the clay cap of a potential geothermal prospect; 4) A large, low-resistivity zone beneath the San Pedro-Tatara Volcanic Complex to the west of LdM at a depth of ~10 km (8 km b.s.l.) is interpreted to be a zone of partial melt. Further MT data collection is planned for 2016 which will expand the current grid of MT stations to better constrain the lateral extent of the observed features and give greater insight into the dynamics of this restless magma system.

  10. An InSAR-based survey of volcanic deformation in the central Andes

    Science.gov (United States)

    Pritchard, M. E.; Simons, M.

    2004-02-01

    We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°-27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); and a caldera (Cerro Blanco, also called Robledo) in northwest Argentina is subsiding. We explore the range of source depths and volumes allowed by our observations, using spherical, ellipsoidal and crack-like source geometries. We further examine the effects of local topography upon the deformation field and invert for a spherical point-source in both elastic half-space and layered-space crustal models. We use a global search algorithm, with gradient search methods used to further constrain best-fitting models. Inferred source depths are model-dependent, with differences in the assumed source geometry generating a larger range of accepted depths than variations in elastic structure. Source depths relative to sea level are: 8-18 km at Hualca Hualca; 12-25 km for Uturuncu; 5-13 km for Lazufre, and 5-10 km at Cerro Blanco. Deformation at all four volcanoes seems to be time-dependent, and only Uturuncu and Cerro Blanco were deforming during the entire time period of observation. Inflation at Hualca Hualca stopped in 1997, perhaps related to a large eruption of nearby Sabancaya volcano in May 1997, although there is no obvious relation between the rate of deformation and the eruptions of Sabancaya. We do not observe any deformation associated with eruptions of Lascar, Chile, at 16 other volcanoes that had recent small eruptions or fumarolic activity, or associated with a short-lived thermal anomaly at Chiliques volcano. We posit a hydrothermal system at Cerro Blanco to explain the

  11. Central nervous system diseases

    International Nuclear Information System (INIS)

    It is shown that roentgenological examination plays an important role in diagnosis of central nervous system diseases in children. The methods of roentgenological examinations are divided into 3 groups: roentgenography without contrast media (conventional roentgenography), roentgenography with artificial contrasting of liquor space (ventriculopneumoencelography, myelography) and contrasting of brain and spinal blood vessels (angiography). Conventional contrastless roentgenography of skull and vertebral column occupies leadership in diagnosis of brain neoplasms and some vascular diseases

  12. Nature, source and composition of volcanic ash in sediments from a fracture zone trace of Rodriguez Triple Junction in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas-Pereira, M.B.L.; Nath, B.N.; Borole, D.V.; Gupta, S.M.

    Volcanic glasses associated with pumice, micro nodules and palagonite like lithic fragments were recovered from a volcanic terrain in a fracture zone defined as Rodriguez Triple Junction trace in the Central Indian Basin. Morphologically, the tephra...

  13. Isotopic Ages of the Carbonatitic Volcanic Rocks in the Kunyang Rift Zone in Central Yunnan,China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongbei; WANG Guilan; NIE Jianfeng; ZHAO Chongshun; XU Chengyan; QIU Jiaxiang; Wang Hao

    2003-01-01

    The Mesoproterozoic Kunyang rift, which is located on the western margin of the Yangtze platform and the southern section of the Kangdian axis, is a rare massive Precambrian iron-copper polymetallic mineralization zone in China. The Mesoproterozoic Wulu (Wuding(Lufeng) basin in the middle of the rift is an elliptic basin controlled by a ring fracture system. Moreover, volcanic activities in the basin display zonation of an outer ring, a middle ring and an inner ring with carbonatitic volcanic rocks and sub-volcanic dykes discovered in the outer and middle rings. The Sm-Nd isochron ages have been determined for the outer-ring carbonatitic lavas (1685 Ma) and basaltic porphyrite of the radiating dyke swarm (1645 Ma) and the Rb-Sr isochron ages for the out-ring carbonatitic lavas (893 Ma) and the middle-ring dykes (1048 Ma). In combination of the U-Pb concordant ages of zircon (1743 Ma) in trachy-andesite of the corresponding period and stratum (1569 Ma) of the Etouchang Formation, as well as the Rb-Sr isochron age (1024 Ma) and K-Ar age (1186 Ma) of the dykes in the middle ring, the age of carbonatites in the basin is preliminarily determined. It is ensured that all of these carbonatites were formed in the Mesoproterozoic period, whereby two stages could be identified as follows: in the first stage, carbonatitic volcanic groups, such as lavas, pyroclastic rocks and volcaniclastic sedimentary rocks, were formed in the outer ring; in the second stage, carbonatitic breccias and dykes appeared in the middle ring. The metamorphic age of the carbonatitic lavas in the outer ring was determined to be concurrent with the end of the first stage of the Neoproterozoic period, corresponding to the Jinning movement in central Yunnan.

  14. The Physics of a Volcanic System: What is the Actual Role Played by Tectonic Setting in Controlling Volcanic Activity?

    Science.gov (United States)

    Canon-Tapia, E.

    2005-12-01

    Modern text-books commonly explain volcanic activity as a direct consequence of plate tectonics, overlooking the different scales characteristic of both types of processes. By acknowledging such differences, however, it is possible to envisage a model of a volcanic system that is based in the same principles of hydrostatics established by Blaise Pascal over 300 yrs ago. Such principles allow us to estimate the local conditions required for the occurrence of volcanism at a given location highlighting the importance of the rock strength and the density difference between melt and its surroundings. This model shows that the minimum thickness of the zone of partial melting in the mantle (or seismically defined Low Velocity Zone) that is required to feed volcanic activity might range from 5 to over 100 km, but also that under certain circumstances a rock strength 600 MPa will not suffice to stop magma ascent resulting in volcanic activity at the surface. Consequently, the model of volcanism developed here explains why is that a given LVZ may lead to volcanic activity in some places whereas a completely identical LVZ may not result in volcanic activity in a different location. Consequently, this model provides a general framework that allows us to better understand the actual role played by tectonic setting in controlling volcanism at a planetary scale.

  15. Geothermal systems in volcanic arcs: Volcanic characteristics and surface manifestations as indicators of geothermal potential and favorability worldwide

    Science.gov (United States)

    Stelling, P.; Shevenell, L.; Hinz, N.; Coolbaugh, M.; Melosh, G.; Cumming, W.

    2016-09-01

    This paper brings a global perspective to volcanic arc geothermal assessments by evaluating trends and correlations of volcanic characteristic and surface manifestation data from world power production sites in subduction zone volcanic settings. The focus of the work was to evaluate volcanic centers individually and as a group in these arcs by correlating various geologic characteristics with known potential to host electricity grade geothermal systems at the volcanic centers. A database was developed that describes key geologic factors expected to be indicative of productive geothermal systems in a global training set, which includes all 74 subduction zone volcanic centers world-wide with current or proven power production capability. Importantly, this data set only contains data from subduction zone volcanoes and contains no negative cases, limiting the populations of any statistical groups. Regardless, this is the most robust geothermal benchmark training set for magmatic-heated systems to date that has been made public. The work reported here is part of a larger project that included data collection, evaluation, correlations and weightings, fairway and favorability modeling and mapping, prediction of blind systems, and uncertainty analysis to estimate errors associated with model predictions. This first paper describes volcano characteristics, compositions and eruption ages and trends along with surface manifestation observations and temperatures as they relate to known power producing systems. Our findings show a strong correlation between the presence and size of active flank fumarole areas and installed power production. Additionally, the majority of volcanic characteristics, including long-held anecdotal correlations related to magmatic composition or size, have limited to no correlation with power production potential. Notable exceptions are correlations between greater power yield from geothermal systems associated with older (Pleistocene) caldera systems

  16. Paleoenvironmental and paleoclimatic changes associated with the Deccan Volcanism, examples from terrestrial deposits from Central India

    Science.gov (United States)

    Fantasia, Alicia; Adatte, Thierry; Spangenberg, Jorge E.; Font, Eric; Samant, Bandana; Mohabey, Dhananjay; Thakre, Deepali; Keller, Gerta

    2015-04-01

    Since the 80's, numerous authors have established the connection between Deccan volcanism in India and the KT events. Chenet et al (2008) showed that Deccan Traps erupted in three main phases with 6% total Deccan volume in phase-1 (base C30n), 80% in phase-2 (C29r) and 14% in phase-3 (C29n). Recent works indicate that the main phase-2 (80%) occurred over a relatively short time interval in magnetic polarity C29r, which coincides with the KTB events (Blair et al., in press, Keller et al, 2012). The biotic evolution is well understood in marine environments, but only few data are available concerning the terrestrial environmental changes. In central India, sedimentary beds associated with the Deccan Traps are represented by infratrappean (Lameta Formation) and intertrappean sediments, which were deposited during periods of volcanic quiescence. These deposits are located at different stratigraphic levels within the basaltic pile and are therefore crucial to evaluate the changes on land induced by the onset of the volcanism. The sedimentary beds exposed in the central part of India in the Jabalpur-Mandla-Chhindwara sector (Madyha Pradesh) and in the Nand-Dongargaon basin (Maharashtra) were studied using a sedimentological, geophysical, geochemical and mineralogical approach. Our results indicate that the intertrappean sediments deposited during the Deccan volcanism do not reflect the same characteristics than the infratrappean sediments preceding the volcanic eruptions. Indeed, palynological studies of the Lameta Formation indicate a dominance of angiosperms and a rich canopy of gymnosperms (Conifers and Podocarpaceae) and an understory of palms and herbs. Moreover, sedimentological and mineralogical observations indicate alluvial-limnic environment under arid climate. The eruption of Deccan volcanic flows severely affected the environmental conditions. Intertrappean sediments associated with the three Deccan phases were deposited in terrestrial to lacustrine

  17. Classification of the ecological status of volcanic lakes in Central Italy

    Directory of Open Access Journals (Sweden)

    Daria VAGAGGINI

    2003-09-01

    Full Text Available A synthesis is made of biological data collected in the last three decades on five volcanic lakes in Central Italy with the aim of evaluating their environmental status by means of biological parameters related to zooplankton, littoral and profundal zoobenthos frequently used to detect water quality changes in lakes. A number of bioindicators and bioindices were selected for this purpose, as far as possible following an integrated approach using information drawn from physical and chemical variables. Our results allowed the lakes to be classified according to their biological quality level, which proved to be in good agreement with physical and chemical diagnoses. Lake Bracciano exhibited the best environmental quality, due to the presence of a ring waste water collecting system, to its large size and depth, and to its strong hydrodynamism. Lake Martignano followed, with some symptoms of stress in the hypolimnion due to a marked summer deoxygenation. Oxygen depletion in the profundal characterized also Lake Vico, which showed a mesotrophic condition in the sixties, and 20 years later now shows clear signs of increased trophy (meso-eutrophy. Lake Albano seemed meso-eutrophic with total absence of fauna below a depth of 120 m due to a meromictic status. Finally Lake Nemi, exposed to domestic wastes in the 70s, suffered a heavy eutrophication with dramatic algal blooms and fish kills. Following the diversion of discharges that occurred in the early 90s, today this lake is characterized by the partial improvement of many ecological features. The need for integration between physical and chemical analyses and biological data in order to obtain a reliable evaluation of lake environmental quality is stressed, especially as far as routine implementation in managing and recovery procedures is concerned.

  18. Chemical Variation and Origin of Pleistocene Silicic Pyroclastic Flows from Central American Volcanic Arc

    Science.gov (United States)

    Patino, L. C.; Vogel, T. A.; Alvarado, G. E.; Rose, W. I.; Viray, E. L.

    2003-12-01

    Silicic pyroclastic flows have occurred along the Central American volcanic arc during the Pleistocene. The volcanic products from these eruptions range in composition have SiO{2} mode of 70 wt.%. In the latest part of the Pleistocene (Costa Rica. Phenocryst phases of the silicic pyroclastic flows along Central America are generally very similar. Plagioclase dominates as phenocryst and in the groundmass. Sub-calcic augite, hypersthene are common in dacites. Amphibole as well as biotite are common in the rhyolites and rhyodacites in Guatemala and El Salvador, but these minerals are absent from all units in Nicaragua, and from the youngest unit in Costa Rica. In addition, Ti-oxides, apatite, quartz, are common. It is worth noting that the silicic rocks from Central America contain very little alkali feldspar. There are some chemical variations in the composition of ash-flow tuffs along the arc. The most primitive materials in ignimbrites from Guatemala and Costa Rica are basaltic andesites and andesites; but in Nicaragua and El Salvador, basaltic scorias are present. The ignimbrites from Central Costa Rica have higher alkali content, than the rest of the Pleistocene ash-flow tuffs from Central America, a pattern similar to that observed in lavas. Furthermore, some trace element and trace element ratios also vary along the arc in a pattern similar to that observed in the lavas. The ignimbrites from Nicaragua tend to have the lowest concentrations of Zr (200 ppm); Ba/Th, U/Th are highest and La/Yb is the lowest in Nicaragua.Fractional crystallization has played a role in the evolution of ash-flow sheets in the Central American volcanic arc. Some samples from Guatemala and El Salvador have Eu/Eu*Caribbean large igneous province in the south, are not possible sources for the Pleistocene silicic pyroclastic flows. Based on the similar key trace-element ratios of the ignimbrites and the arc lavas, we concluded that remelting of the calc-alkaline plutons, emplaced at depth

  19. Toward an integrated Volcanic Ash Observing System in Europe

    Science.gov (United States)

    Lee, Deborah; Lisk, Ian

    2014-05-01

    Volcanic ash from the Icelandic eruption of Eyjafjallajökull in April and May of 2010 resulted in the decision by many northern European countries to impose significant restrictions on the use of their airspace. The eruption, extent and persistence of the ash revealed how reliant society now is on a safe and efficient air transport system and the fragility of that system when affected by the impact of complex natural hazards. As part of an EC framework programme, the 2011-2013 WEZARD (WEather HaZARD for aeronautics) consortium conducted a cross-industry volcanic ash capability and gap analyses, with the EUMETNET (network of 29 National Meteorological Services) led Work Package 3 focussing on a review of observational and monitoring capabilities, atmospheric dispersion modelling and data exchange. The review has revealed a patchwork of independent observing capabilities for volcanic ash, with some countries investing and others not at all, and most existing networks focus on space-based products. Existing capabilities do not provide the necessary detail on the geographical and vertical extent of volcanic ash and associated levels of contamination, which decision makers in the aviation industry require in order to decide where it is safe to fly. A resultant high priority was identified by WEZARD Work Package 3 for an enhanced observational network of complementary monitoring systems needed to initialise, validate and verify volcanic ash dispersion model output and forecasts. Thus a key recommendation is to invest in a major pre-operational demonstrator "European volcanic ash observing network", focussing on distal monitoring, and aiming to a) fill R&D gaps identified in instrumentation and algorithms and b) integrate data, where possible in near-real-time, from a range of ground-based, airborne and space-based techniques. Here we present a key WEZARD recommendation toward an integrated volcanic ash observing system in Europe, in context with other related projects

  20. Volcanic Gas Emissions Mapping Using a Mass Spectrometer System

    Science.gov (United States)

    Griffin, Timothy P.; Diaz, J. Andres

    2008-01-01

    The visualization of hazardous gaseous emissions at volcanoes using in-situ mass spectrometry (MS) is a key step towards a better comprehension of the geophysical phenomena surrounding eruptive activity. In-Situ gas data consisting of helium, carbon dioxide, sulfur dioxide, and other gas species, were acquired with an MS system. MS and global position system (GPS) data were plotted on ground imagery, topography, and remote sensing data collected by a host of instruments during the second Costa Rica Airborne Research and Technology Applications (CARTA) mission This combination of gas and imaging data allowed 3-dimensional (3-D) visualization of the volcanic plume end the mapping of gas concentration at several volcanic structures and urban areas This combined set of data has demonstrated a better tool to assess hazardous conditions by visualizing and modeling of possible scenarios of volcanic activity. The MS system is used for in-situ measurement of three-dimensional gas concentrations at different volcanic locations with three different transportation platforms, aircraft, auto, and hand carried. The demonstration for urban contamination mapping is also presented as another possible use for the MS system.

  1. Shallow crustal structure of eastern-central Trans-Mexican Volcanic Belt.

    Science.gov (United States)

    Campos-Enriquez, J. O.; Ramón, V. M.; Lermo-Samaniego, J.

    2015-12-01

    Central-eastern Trans-Mexican Volcanic Belt (TMVB) is featured by large basins (i.e., Toluca, Mexico, Puebla-Tlaxcala, Libres-Oriental). It has been supposed that major crustal faults limit these basins. Sierra de Las Cruces range separates the Toluca and Mexico basins. The Sierra Nevada range separates Mexico basin from the Puebla-Tlaxcala basin. Based in gravity and seismic data we inferred the Toluca basin is constituted by the Ixtlahuaca sub-basin, to the north, and the Toluca sub-basin to the south, which are separated by a relative structural high. The Toluca depression is more symmetric and bounded by sub-vertical faults. In particular its eastern master fault controlled the emplacement of Sierra de Las Cruces range. Easternmost Acambay graben constitutes the northern and deepest part of the Ixtlahuaca depression. The Toluca-Ixtlahuaca basin is inside the Taxco-San Miguel de Allende fault system, and limited to the west by the Guerrero terrane which continues beneath the TMVB up to the Acambay graben. Mexico basin basement occupies an intermediate position and featured by a relative structural high to the north-east, as established by previous studies. This relative structural high is limited to the west by the north-south Mixhuca trough, while to the south it is bounded by the east-west Copilco-Xochimilco-Chalco sub-basin. The Puebla-Tlaxcala basin basement is the shallowest of these 3 tectonic depressions. In general, features (i.e., depth) and relationship between these basins, from west to east, are controlled by the regional behavior of the Sierra Madre Oriental fold and thrust belt basement (i.e., Oaxaca Complex?). This study indicates that an active east-west regional fault system limits to the south the TMVB (from the Nevado de Toluca volcano through the Popocatepetl volcano and eastward along southern Puebla-Tlaxcala basin). The Tenango and La Pera fault systems constituting the western part of this regional fault system coincide with northern

  2. Geodynamical evolution of Central Andes at 24°S as inferred by magma composition along the Calama-Olacapato-El Toro transversal volcanic belt

    Science.gov (United States)

    Matteini, M.; Mazzuoli, R.; Omarini, R.; Cas, R.; Maas, R.

    2002-11-01

    Miocene to Recent volcanism on the Puna plateau (Central Andes) developed in three geological settings: (a) volcanic arc in the Western Cordillera (Miocene-Recent); (b) trans-arc along the main NW-SE transverse fault systems (Miocene); and (c) back-arc, mainly monogenic volcanic centres (Pliocene-Quaternary). We have studied the evolution of the arc-trans-arc volcanism along one of the most extensive transverse structures of Central Andes, the Calama-Olacapato-El Toro, at 24°S. Compositional variations from arc to trans-arc volcanism provide insights into petrogenesis and magma source regions. Puntas Negras and Rincon volcanic centres are arc-type and have typical calc-alkaline geochemical and Sr-Nd-Pb isotopic characteristics. East of the arc, lavas of the Tul-Tul, Del Medio and Pocitos complexes (TUMEPO) are heavy rare earth element-depleted and could be derived from 20-30% of partial melting of a lower crustal garnet-bearing metabasite. These liquids could be variably mixed with arc magmas at the base of the crust (MASH). This suggests important contributions from lower crustal sources to TUMEPO centres. Products at the Quevar and Aguas Calientes volcanic complexes to the east of TUMEPO show a prominent upper crustal signature (high 86Sr/ 87Sr, low 143Nd/ 144Nd) and could represent mixtures of 20-30% TUMEPO-type liquids with up to 70-80% of upper crustal melts. We propose a geodynamic model to explain geochemical variations for the arc-trans-arc transverse volcanism from the Upper Miocene to Recent. In our model, arc volcanism is linked to dehydration of the subducting Nazca plate, which produces typical calc-alkaline compositions. During the Upper Miocene (10-5 Ma), lithospheric evolution in the Puna plateau was dominated by thickening of ductile lower crust and thinning of the lithosphere. Lower crustal melting was promoted by concomitant asthenospheric upwelling and water release from the amphibolite-eclogite transformation, yielding TUMEPO magmas with lower

  3. Late Cenozoic volcanism in central Myanmar: Geochemical characteristics and geodynamic significance

    Science.gov (United States)

    Lee, Hao-Yang; Chung, Sun-Lin; Yang, Hsiao-Ming

    2016-02-01

    Late Cenozoic volcanism occurred in the central Myanmar basin, a region that is marked by the existence of the dextral Sagaing fault linking the eastern Himalayan Syntaxis to the north and the Andaman Sea to the south. Here we report new geochemical data of volcanic rocks from Monywa, Mt. Popa and Singu areas erupting in two distinct stages, i.e., mid-Miocene and Quaternary, respectively. While calc-alkaline rocks showing arc-like geochemical features are abundant, an apparent change in magma composition is observed between these two stages. The mid-Miocene rocks are mainly dominated by intermediate compositions (SiO2 = 53-61 wt.%) and typical of high-K calc-alkaline nature. They exhibit uniform Sr and Nd isotopic ratios (ISr ≈ ~ 0.705; εNd(T) = + 2.7 to + 1.6), suggesting a juvenile mantle origin related to the subduction of Indian oceanic lithosphere beneath this part of Asia. The Quaternary rocks consist mainly of basalts that, however, show variations in geochemical features. Three suites in this stage are observed: (1) calc-alkaline suite (basalts and basaltic andesites from Monywa and Mt. Popa: SiO2 = 48-56 wt.%; ISr = 0.704 to 0.705; εNd(T) = + 3.1 to + 2.1), originating from partial melting of a "remnant" juvenile mantle wedge, (2) alkali basalt suite I (basanites from Monywa: SiO2 ≈ 45 wt.%; MgO = 10-12 wt.%; K2O ≈ 2.0 wt.%; ISr = 0.704 to 0.705; εNd(T) ≈ + 3.6), interpreted as the product of small-degree melting from an amphibole lherzolite in the lithospheric mantle, and (3) alkali basalt suite II (trachybasalts from Singu: SiO2 ≈ 51 wt.%; K2O = 2.6-3.5 wt.%; ISr ≈ 0.706; εNd(T) = + 1.6 to + 0.9), interpreted as the product of partial melting from the asthenosphere. All processes of magma generation were related to the India-Asia collision that caused regional plate reorganization, a transition from oblique subduction to dextral movement in the Miocene, and subsequent "rollback" of the subducted Indian oceanic lithosphere in the

  4. The 10 April 2014 Nicaraguan Crustal Earthquake: Evidence of Complex Deformation of the Central American Volcanic Arc

    Science.gov (United States)

    Suárez, Gerardo; Muñoz, Angélica; Farraz, Isaac A.; Talavera, Emilio; Tenorio, Virginia; Novelo-Casanova, David A.; Sánchez, Antonio

    2015-11-01

    northwest relative to the Caribbean plate at a rate of 14 mm/year. Part of the deformation is apparently accommodated by strain partitioning in the form of bookshelf faulting, on a system of orthogonal faults. The sinistral faults striking northeast-southwest rotate blocks of the Caribbean plate in a clockwise manner. The recent crustal earthquakes in central Nicaragua in 1931, 1972 and 2005 earthquakes took place on these left-lateral faults. The motion of the forearc sliver is also accommodated by a second set of right-lateral, strike-slip faults oriented parallel to the volcanic arc. Faults with this orientation and direction of motion are responsible for the 2014 and possibly the 1955 earthquakes. The presence of this geometry of orthogonal crustal faults highlights the seismic hazard posed by this complex faulting system, not only in the capital city of Managua, but also to the major Nicaraguan cities, which lie close to the volcanic arc.

  5. Bimodal volcanism in a tectonic transfer zone: Evidence for tectonically controlled magmatism in the southern Central Andes, NW Argentina

    Science.gov (United States)

    Petrinovic, I. A.; Riller, U.; Brod, J. A.; Alvarado, G.; Arnosio, M.

    2006-04-01

    This field-based and analytical laboratory study focuses on the genetic relationship between bimodal volcanic centres and fault types of an important tectonic transfer zone in the southern Central Andes, the NW-SE striking Calama-Olacapato-Toro (COT) volcanic belt. More specifically, tectono-magmatic relationships are examined for the 0.55 Ma Tocomar, the 0.78 Ma San Jerónimo and the 0.45 Ma Negro de Chorrillos volcanic centres in the Tocomar area (66°30 W-24°15 S). Structures of the COT volcanic belt, notably NW-SE striking strike-slip faults and NE-SW trending normal faults, accommodated differential shortening between major N-S striking thrust faults on the Puna Plateau. We present evidence that bimodal volcanism was contemporaneous with activity of these fault types in the COT volcanic belt, whereby eruption and composition of the volcanic rocks in the Tocomar and San Jerónimo-Negro de Chorrillos areas appear to have been controlled by the kinematics of individual faults. More specifically, rhyolitic centres such as the Tocomar are associated with normal faults, whereas shoshonitic-andesitic monogenetic volcanoes, e.g., the San Jerónimo and Negro de Chorrillos centres, formed at strike-slip dominated faults. Thus, the eruption of higher viscous rhyolite magmas appears to have been facilitated in tectonic settings characterized by horizontal dilation whereas ascent and effusive volcanic activity of less viscous and hot basaltic andesites to shoshonites were controlled by subvertical strike-slip faults. While the Tocomar rhyolites are interpreted to be derived from an anatectic crustal source, geochemical characteristics of the San Jerónimo and Negro de Chorrillos shoshonitic andesites are in agreement with a deeper source. This suggests that the composition of erupted volcanic rocks as well as their spatial distribution in the Tocomar area is controlled by the activity of specific fault types. Such volcano-tectonic relationships are also evident from older

  6. Results From NICLAKES Survey of Active Faulting Beneath Lake Nicaragua, Central American Volcanic Arc

    Science.gov (United States)

    Funk, J.; Mann, P.; McIntosh, K.; Wulf, S.; Dull, R.; Perez, P.; Strauch, W.

    2006-12-01

    In May of 2006 we used a chartered ferry boat to collect 520 km of seismic data, 886 km of 3.5 kHz subbottom profiler data, and 35 cores from Lake Nicaragua. The lake covers an area of 7700 km2 within the active Central American volcanic arc, forms the largest lake in Central America, ranks as the twentieth largest freshwater lake in the world, and has never been previously surveyed or cored in a systematic manner. Two large stratovolcanoes occupy the central part of the lake: Concepcion is presently active, Maderas was last active less than 2000 years ago. Four zones of active faulting and doming of the lake floor were mapped with seismic and 3.5 kHz subbottom profiling. Two of the zones consist of 3-5-km-wide, 20-30-km-long asymmetric rift structures that trend towards the inactive cone of Maderas Volcano in a radial manner. The northeastern rift forms a 20-27-m deep depression on the lake bottom that is controlled by a north-dipping normal fault. The southwestern rift forms a 25-35-m deep depression controlled by a northeast-dipping normal fault. Both depressions contain mound-like features inferred to be hydrothermal deposits. Two zones of active faulting are associated with the active Concepcion stratovolcano. A 600-m-wide and 6-km-long fault bounded horst block extends westward beneath the lake from a promontory on the west side of the volcano. Like the two radial rift features of Maderas, the horst points roughly towards the active caldera of Concepcion. A second north-south zone of active faulting, which also forms a high, extends off the north coast of Concepcion and corresponds to a localized zone of folding and faulting mapped by previous workers and inferred by them to have formed by gravitational spreading of the flank of the volcano. The close spatial relation of these faults to the two volcanic cones in the lake suggests that the mechanism for faulting is a result of either crustal movements related to magma intrusion or gravitational sliding and is

  7. Explosive properties of water in volcanic and hydrothermal systems

    OpenAIRE

    Thiery, Régis; Mercury, Lionel

    2009-01-01

    International audience This paper describes, from a thermodynamic point of view, the physicochemical conditions, under which water behaves as an explosive. This phenomenon occurs frequently in hydrothermal and volcanic systems when water is brutally shifted from its initial equilibrium state. Water (either liquid or gas) becomes metastable or unstable and reequilibrates by violent demixing of a liquid-gas mixture. In a first step, a phenomenological approach of metastability is given in a ...

  8. On-and offshore tephrostratigraphy and -chronology of the southern Central American Volcanic Arc (CAVA)

    Science.gov (United States)

    Schindlbeck, J. C.; Kutterolf, S.; Hemming, S. R.; Wang, K. L.

    2015-12-01

    Including the recently drilled CRISP sites (IODP Exp. 334&344) the deep sea drilling programs have produced 69 drill holes at 29 Sites during 9 Legs at the Central American convergent margin, where the Cocos plate subducts beneath the Caribbean plate. The CAVA produced numerous plinian eruptions in the past. Although abundant in the marine sediments, information and data regarding large late Cenozoic explosive eruptions from Costa Rica, Nicaragua, Honduras, El Salvador, and Guatemala remain very sparse and discontinuous on land. We have established a tephrostratigraphy from recent through Miocene times from the unique archive of ODP/IODP sites offshore Central America in which we identify tephra source regions by geochemical fingerprinting using major and trace element glass shard compositions. Here we present first order correlations of ­~500 tephra layers between multiple holes at a single site as well as between multiple sites. We identified ashes supporting Costa Rican (~130), Nicaraguan (17) and Guatemalan (27) sources as well as ~150 tephra layers from the Galápagos hotspot. Within our marine record we also identified well-known marker beds such as the Los Chocoyos tephra from Atitlán Caldera in Guatemala and the Tiribi Tuff from Costa Rica but also correlations to 15 distinct deposits from known Costa Rican and Nicaraguan eruptions within the last 4.1 Ma. These correlations, together with new radiometric age dates, provide the base for an improved tephrochronostratigraphy in this region. Finally, the new marine record of explosive volcanism offshore southern CAVA provides insights into the eruptive history of long-living volcanic complexes (e.g., Barva, Costa Rica) and into the distribution and frequency of large explosive eruptions from the Galápagos hotspot. The integrated approach of Ar/Ar age dating, correlations with on land deposits from CAVA, biostratigraphic ages and sediment accumulation rates improved the age models for the drilling sites.

  9. Reverse Faulting as a Crucial Mechanism for Magma Ascent in Compressional Volcanic Arcs: Field Examples from the Central Andes

    Science.gov (United States)

    Aron, F. A.; Gonzalez, G.; Cembrano, J. M.; Veloso, E. E.

    2010-12-01

    The nature of crustal deformation in active arcs and the feedback mechanisms between tectonics and magma transport constitute fundamental problems in the understanding of volcanic systems. Additionally, for geothermal energy exploration, a better understanding of how crustal architecture and stress field controls fluid ascent and heat transfer from deep levels to the surface is crucial. The Central Andes volcanic belt is an excellent, modern example of such systems but, the scarcity of good outcrops has limited our ability to define the relations between structure and volcanism. In the Salar de Atacama Basin of northern Chile, there are good exposures of folded and faulted Neogene units (continental sediments, volcanic rocks and ignimbrites) and reverse faults spatially and temporally related to volcanic edifices. The subsurface of the study area has been interpreted by previous authors as a thin-skinned, 6-8 km-deep, east-vergent compressional belt. We carried out structural mapping, Digital Elevation Models (DEMs) analyses, strain tensor analyses and fault-related fold kinematic modelling to assess the causal relationship between compressional deformation and magmatism in this region. Field observations indicate that the structures deformed progressively Oligocene-Miocene continental sedimentary units, the upper sedimentary infill of the Salar de Atacama basin (Pliocene-Present), and Pliocene-Pleistocene Ignimbrites. The topographic expression of the compressional belt corresponds to a set of subparallel, asymmetric, fault-related-folds, which can be seen in the field as prominent NS-trending ridges with heights ranging between 50 and 400 m. Furthermore, we found evidence of a ~100 km-long structure along the active magmatic arc, so-called Miscanti Fault. This fault represents the easternmost expression of the above mentioned compressional belt. Pleistocene-Holocene monogenetic cones and strato-volcanoes are located either at the hinge zone of fault

  10. Central nervous system tumors

    International Nuclear Information System (INIS)

    Central nervous system (CNS) tumors are relatively common in veterinary medicine, with most diagnoses occurring in the canine and feline species. Numerous tumor types from various cells or origins have been identified with the most common tumors being meningiomas and glial cell tumors. Radiation therapy is often used as an aid to control the clinical signs associated with these neoplasms. In general, these tumors have a very low metastatic potential, such that local control offers substantial benefit. Experience in veterinary radiation oncology would indicate that many patients benefit from radiation treatment. Current practice indicates the need for computed tomography or magnetic resonance imaging studies. These highly beneficial studies are used for diagnosis, treatment planning, and to monitor treatment response. Improvements in treatment planning and radiation delivered to the tumor, while sparing the normal tissues, should improve local control and decrease potential radiation related problems to the CNS. When possible, multiple fractions of 3 Gy or less should be used. The tolerance dose to the normal tissue with this fractionation schedule is 50 to 55 Gy. The most common and serious complications of radiation for CNS tumors is delayed radiation myelopathy and necrosis. Medical management of the patient during radiation therapy requires careful attention to anesthetic protocols, and medications to reduce intracranial pressure that is often elevated in these patients. Canine brain tumors have served as an experimental model to test numerous new treatments. Increased availability of advanced imaging modalities has spawned increased detection of these neoplasms. Early detection of these tumors with appropriate aggressive therapy should prove beneficial to many patients

  11. Sr-Nd isotope changes of late cretaceous to early miocene volcanic rocks in central Chile (33oS)

    International Nuclear Information System (INIS)

    A longitudinal depression, the Central Valley, separates the Coast Range from the Andean Cordillera in central Chile. It contains volcanic and volcaniclastic rocks of Late Cretaceous to Tertiary age deposited in a continental environment, and partly eroded Tertiary volcanic complexes. The age of the rocks at the northern end of the Central Valley and their grouping in formations have been a long-standing controversy in Chilean geology (Thomas, 1958; Aguirre, 1960; Drake et al., 1976; Vergara and Drake, 1979; Thiele, 1980; Moscoso et al., 1982; Gana and Wall, 1997; Lopez-Escobar and Vergara, 1997; Selles, 1999). Here, we report new 40Ar/39Ar data and Sr-Nd isotope ratios for lavas, pyroclastic flows and associated subvolcanic rocks from this part of central Chile (au)

  12. Occurrence of an unknown Atlantic eruption in the Chaîne des Puys volcanic field (Massif Central, France)

    Science.gov (United States)

    Jouannic, G.; Walter-Simonnet, A. V.; Bossuet, G.; Cubizolle, H.; Boivin, P.; Devidal, J. L.; Oberlin, C.

    2014-08-01

    A volcanic ash layer, called MF1, was recently identified in Holocene sediments from the Gourgon and Molhiac peat bogs (Monts du Forez, French Massif Central). This ash layer consists of colorless shards with a heterogeneous trachytic to rhyolitic composition. The trace elements analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) attest to a local origin. Radiocarbon dating of peat samples taken within and below the ash layer indicates the best age at 6339 ± 61 cal yr BP, i.e. an age contemporaneous with the volcanic activity of Montchal, Montcineyre and Pavin volcanoes from the Chaîne des Puys volcanic field. These volcanoes are characterized by basaltic and trachytic products, thus the rhyolitic composition of MF1 tephra suggests that it is likely originated from an unknown eruption. These results again confirm the interest of studying the distal volcanic ash fallouts in order to establish or specify records of past eruptions of volcanic fields. Identification of this new tephra layer also provides an additional tephrochronological marker for Eastern French Massif Central.

  13. Geothermal prospecting by geochemical methods in the Quaternary volcanic province of Dhamar (central Yemen)

    Science.gov (United States)

    Minissale, Angelo; Vaselli, Orlando; Mattash, Mohamed; Montegrossi, Giordano; Tassi, Franco; Ad-Dukhain, Abdulsalam; Kalberkamp, Ulrich; Al-Sabri, Ali; Al-Kohlani, Taha

    2013-01-01

    This paper deals with geothermal prospecting carried out in the Quaternary volcanic field of Dhamar, which is located almost in the centre of the main Oligo-Miocene basaltic trap plateau of Yemen. By applying geochemical and thermometric techniques in domestic wells producing water from the shallow unconfined aquifer in the area, which is prevalently hosted inside the Quaternary volcano-clastic material, a closed thermal anomaly associated with the Quaternary volcanic activity was well delineated. Although the aquifer(s) has a Ca-Na-HCO3 composition, that is typical of shallow groundwater, there are several chemical anomalies in the hotter central area compared to typical aquifers: i) the pH is lower and, consequently, the calculated partial pressure of CO2 in solution is higher, ii) the electrical conductivity is higher, iii) the total salinity is higher and iv) the fluoride ion concentration is higher. Such chemical anomalies in the hotter part of the aquifer do not seem to be generated by the rising and/or mixing of deep hydrothermal components rising into the shallow aquifer, but rather produced by enhanced water-rock interaction processes resulting from the higher temperature of the aquifer and its greater acidity. By applying some speculative calculations, based on the likely temperature of rainfall in the area and the depth and temperature of individual wells, the local thermal gradients in the area have been calculated. The thermal gradient varies from less than the average Earth gradient at the periphery of the delimitated thermal anomaly, to more than 250 °C/km, within an extensive area (exceeding 200 km2) where the gradient is greater than 100/120 °C/km.

  14. Identifying the volcanic eruption depicted in a neolithic painting at Catalhoyuk, Central Anatolia, Turkey.

    Directory of Open Access Journals (Sweden)

    Axel K Schmitt

    Full Text Available A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th/He zircon geochronology. The (U-Th/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ overlaps closely with (14C ages for cultural strata at Çatalhöyük, including level VII containing the "map" mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka. Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard.

  15. Results from NICLAKES Survey of Active Faulting Beneath Lake Managua,Central American Volcanic arc

    Science.gov (United States)

    McIntosh, K.; Funk, J.; Mann, P.; Perez, P.; Strauch, W.

    2006-12-01

    Lake Managua covers an area of 1,035 km2 of the Central American volcanic arc and is enclosed by three major stratovolcanoes: Momotombo to the northwest was last active in AD 1905, Apoyeque in the center on the Chiltepe Peninsula was last active ca. 4600 years BP, and Masaya to the southeast was last active in AD 2003. A much smaller volcano in the lake (Momotombito) is thought to have been active <4500 yrs B.P. In May of 2006, we used a chartered barge to collect 330 km of 3.5 kHz profiler data along with coincident 274 km of sidescan sonar and 27 km of seismic reflection data. These data identify three zones of faulting on the lake floor: 1) A zone of north-northeast-striking faults in the shallow (2.5-7.5 m deep) eastern part of the lake that extends from the capital city of Managua, which was severely damaged by shallow, left-lateral strike-slip displacements on two of these faults in 1931 (M 5.6) and 1972 (M 6.2): these faults exhibit a horst and graben character and include possible offsets on drowned river valleys 2) a semicircular rift zone that is 1 km wide and can be traced over a distance of 30 km in the central part of the lake; the rift structure defines the deepest parts of the lake ranging from 12 to 18 m deep and is concentric about the Apoyeque stratocone/Chiltepe Peninsula; and 3) a zone of fault scarps defining the northwestern lake shore that may correlate to the northwestern extension of the Mateare fault zone, a major scarp-forming fault that separates the Managua lowlands from the highlands south and west of the city. Following previous workers, we interpret the northeast- trending group of faults in the eastern part of the lake as part of a 15-km-long discontinuity where the trend of the volcanic arc is offset in a right-lateral sense. The semi-circular pattern of the rift zone that is centered on Chiltepe Peninsula appears to have formed as a distal effect of either magma intrusion or withdrawal from beneath this volcanic complex. The

  16. Bromine and chlorine emissions from Plinian eruptions along the Central American Volcanic Arc: From source to atmosphere

    Science.gov (United States)

    Kutterolf, Steffen; Hansteen, Thor H.; Freundt, Armin; Wehrmann, Heidi; Appel, Karen; Krüger, Kirstin; Pérez, Wendy

    2015-11-01

    Large explosive volcanic eruptions inject gases, aerosols, and fine ashes into the stratosphere, potentially influencing climate and atmosphere composition on a global scale. Although the potential climate effect of chlorine (Cl) and bromine (Br) injections into the stratosphere is known, the global mass fluxes are poorly constrained. In this study we focus on the magmatic degassing systematics and budgets of Br and Cl, and on constraining the major sources of Br in a subduction setting. We therefore present a regional time series of Br and Cl emissions from 29 highly explosive eruptions throughout the Central American Volcanic Arc (CAVA), covering the last 200 ka, and a range of magmatic compositions and eruption magnitudes. We have measured Br and Cl in matrix glasses and melt inclusions using synchrotron radiation micro X-ray fluorescence spectrometry (SR micro-XRF) and electron microprobe, respectively. Melt inclusions of the CAVA tephras generally have higher Br (0.9 to 17.9 ppm) and Cl (770 to 3800 ppm) contents than the matrix glasses (0.39 to 1.5 ppm Br, 600 to 2800 ppm Cl). Moreover, the difference between maximum and minimum concentrations observed in melt inclusions of a given sample ranges between 9 and 90% of the maximum observed concentration for Br, and between 2 and 40% for Cl. Such intra-sample variations arise from variable pre-eruptive degassing of these halogens into a magmatic fluid phase. The relative loss of Br from the melt is 4 to 68 times higher than that of Cl. The masses of Br (2-1100 kt) and Cl (0.1 to 800 Mt) emitted by the eruptions generate instantaneous additions to the stratosphere potentially amounting to ∼6-5600% of the present-day stratospheric annual global loading of Equivalent Effective Stratospheric Chlorine. As the size of the stratospheric impact is primarily a function of eruption magnitude, we use magnitude-frequency relationships to estimate that eruptions adding ∼10% to resident EESC loading would occur every

  17. Central Verification System

    Data.gov (United States)

    US Agency for International Development — CVS is a system managed by OPM that is designed to be the primary tool for verifying whether or not there is an existing investigation on a person seeking security...

  18. A petrologic study of the Teanaway Basalt: Eocene slab window volcanism in central WA

    Science.gov (United States)

    Roepke, E.; Tepper, J. H.; Ivener, D.

    2013-12-01

    The Teanaway Basalt (TB) includes subaerial basalt to andesite flows, mafic to felsic tuffs, and rhyolite domes in the Central Cascades of Washington State. These volcanics overlie the extensive ~47 Ma Teanaway Dike Swarm (TDS) that cuts the underlying Swauk Formation. This study focuses on the tectonic setting of eruption and geochemical variations relating to geography and stratigraphy within the TB. The western-most area of the TB, Easton Ridge (ER), is compared with the eastern-most area of the TB, Liberty Ridge (LR) - 40 km to the east of ER. The bimodal TB consists predominantly of basaltic andesite and andesite (45.3-63.1 wt% SiO2) with subordinate rhyolite (75.9-79.4 wt% SiO2). The mafic rocks classify as primarily medium-K tholeiites (0.1-3.0 wt% K2O), but a few samples classify as alkaline. Enrichment in LILE and depletion in HFSE on spidergrams are indicative of an arc setting. However, compared with the modern Cascade Arc, the TB is distinctly higher in Fe2O3T (8.8-17.1 wt%) and TiO2 (1.1-2.7 wt%), and distinctly lower in Al2O3 (11.2-14.6) and K2O, with a similar range of Mg #s (0.15-0.48). Most tectonic discrimination plots characterize the TB as MORB, but some indicate an arc or within-plate setting. Preliminary Pb isotopic data (206Pb/204Pb = 19.13-19.19, 207Pb/204Pb = 15.62-15.64, and 208Pb/204Pb = 38.78-38.90) indicate the TB and TDS are more enriched than Cascade Arc rocks in 206Pb/204Pb and 208Pb/204Pb. Overall, these geochemical data are consistent with a model in which asthenospheric mantle ascending through a slab window interacts with mantle wedge that has previously acquired arc chemical traits. The existence of a slab window in this region during the mid-Eocene is compatible with plate reconstructions and evidence of extension that have been attributed to subduction of the Resurrection-Kula ridge (Haeussler et al., 2003). Harker plots show lavas at LR are generally more enriched than those at ER in Fe2O3T (11.9-17.1 wt% vs 8.8-15.7 wt%) Mn

  19. Centralized versus Decentralized Information Systems

    Science.gov (United States)

    Hugoson, Mats-Åke

    This paper brings into question whether information systems should be centralized or decentralized in order to provide greater support for different business processes. During the last century companies and organizations have used different approaches for centralization and decentralization; a simple answer to the question does not exist. This paper provides a survey of the evolution of centralized and decentralized approaches, mainly in a Nordic perspective. Based on critical reflections on the situation in the end of the century we can discuss what we can learn from history to achieve alignment between centralized and decentralized systems and the business structure. The conclusion is that theories, management and practice for decisions on centralization or decentralization of information systems must be improved. A conscious management and control of centralization /decentralization of IT support is a vital question in the company or the organization, and this is not a task that can be handled only by IT-specialists. There is a need for business oriented IT management of centralization/decentralization.

  20. Novel central nervous system drug delivery systems.

    Science.gov (United States)

    Stockwell, Jocelyn; Abdi, Nabiha; Lu, Xiaofan; Maheshwari, Oshin; Taghibiglou, Changiz

    2014-05-01

    For decades, biomedical and pharmaceutical researchers have worked to devise new and more effective therapeutics to treat diseases affecting the central nervous system. The blood-brain barrier effectively protects the brain, but poses a profound challenge to drug delivery across this barrier. Many traditional drugs cannot cross the blood-brain barrier in appreciable concentrations, with less than 1% of most drugs reaching the central nervous system, leading to a lack of available treatments for many central nervous system diseases, such as stroke, neurodegenerative disorders, and brain tumors. Due to the ineffective nature of most treatments for central nervous system disorders, the development of novel drug delivery systems is an area of great interest and active research. Multiple novel strategies show promise for effective central nervous system drug delivery, giving potential for more effective and safer therapies in the future. This review outlines several novel drug delivery techniques, including intranasal drug delivery, nanoparticles, drug modifications, convection-enhanced infusion, and ultrasound-mediated drug delivery. It also assesses possible clinical applications, limitations, and examples of current clinical and preclinical research for each of these drug delivery approaches. Improved central nervous system drug delivery is extremely important and will allow for improved treatment of central nervous system diseases, causing improved therapies for those who are affected by central nervous system diseases.

  1. Fluid escape structures in the Graham Bank region (Sicily Channel, Central Mediterranean) revealing volcanic and neotectonic activity.

    Science.gov (United States)

    Spatola, Daniele; Pennino, Valentina; Basilone, Luca; Interbartolo, Francesco; Micallef, Aaron; Sulli, Attilio; Basilone, Walter

    2016-04-01

    In the Sicily Channel, (Central Mediterranean), two geodynamic processes overlap each other, the Maghrebides-Apennines accretionary prism and the Sicily Channel rift. Moreover, the northwestern sector (Banks sector) is characterised by an irregular seafloor morphology linked to the recent volcanic and tectonic activity.In order to discriminate the role exerted by both the processes in the morphostructural setting of the area we used a dataset of both high and very high resolution single-channel and multi-channel profiles, acquired in the frame of the RITMARE project respectively with CHIRP and sparker, and airgun sources, and high resolution (5 m cell) morpho-bathymetric data. The data allowed us to identify and characterise two areas where different geological features (sedimentary and volcanic) are prevailing. They present fluid escaping evidence, which often appears to be active and generating different types of morphologies (both positive and negative). In the western sector we recognised pockmarks at water depths of 195 to 317 m, with diameters from 25 to 580 m, depths from 1.3 to 15 m, and slope up to 23°. They show sub-circular shape in plan-view and reflectors with upward concavity in cross section, and are oriented along a NW-SE trend.The CHIRP and multichannel profiles highlight fluids that affect the Plio-Quaternary succession, especially in areas where the top surface of the Messinian succession is shallower. Conversely, wipe-out acoustic facies were recognised in proximity of: i) extensional faults of Mesozoic age with NW-SE trend; ii) dip/strike slip faults of Cenozoic age with NW-SE, N-S and about NNE-SSW trends, and iii) extensional neo-tectonic faults with NW-SE and NNW-SSE trends. We cannot exclude that they could feed the shallower reservoir producing a mixing between the two. In the eastern sector we recognised a cluster of volcanoes composed of seven cone-shaped structures (SCV1-7), pertaining to a wide area known as Graham Bank. A detailed

  2. Network centrality of metro systems.

    Directory of Open Access Journals (Sweden)

    Sybil Derrible

    Full Text Available Whilst being hailed as the remedy to the world's ills, cities will need to adapt in the 21(st century. In particular, the role of public transport is likely to increase significantly, and new methods and technics to better plan transit systems are in dire need. This paper examines one fundamental aspect of transit: network centrality. By applying the notion of betweenness centrality to 28 worldwide metro systems, the main goal of this paper is to study the emergence of global trends in the evolution of centrality with network size and examine several individual systems in more detail. Betweenness was notably found to consistently become more evenly distributed with size (i.e. no "winner takes all" unlike other complex network properties. Two distinct regimes were also observed that are representative of their structure. Moreover, the share of betweenness was found to decrease in a power law with size (with exponent 1 for the average node, but the share of most central nodes decreases much slower than least central nodes (0.87 vs. 2.48. Finally the betweenness of individual stations in several systems were examined, which can be useful to locate stations where passengers can be redistributed to relieve pressure from overcrowded stations. Overall, this study offers significant insights that can help planners in their task to design the systems of tomorrow, and similar undertakings can easily be imagined to other urban infrastructure systems (e.g., electricity grid, water/wastewater system, etc. to develop more sustainable cities.

  3. Network centrality of metro systems.

    Science.gov (United States)

    Derrible, Sybil

    2012-01-01

    Whilst being hailed as the remedy to the world's ills, cities will need to adapt in the 21(st) century. In particular, the role of public transport is likely to increase significantly, and new methods and technics to better plan transit systems are in dire need. This paper examines one fundamental aspect of transit: network centrality. By applying the notion of betweenness centrality to 28 worldwide metro systems, the main goal of this paper is to study the emergence of global trends in the evolution of centrality with network size and examine several individual systems in more detail. Betweenness was notably found to consistently become more evenly distributed with size (i.e. no "winner takes all") unlike other complex network properties. Two distinct regimes were also observed that are representative of their structure. Moreover, the share of betweenness was found to decrease in a power law with size (with exponent 1 for the average node), but the share of most central nodes decreases much slower than least central nodes (0.87 vs. 2.48). Finally the betweenness of individual stations in several systems were examined, which can be useful to locate stations where passengers can be redistributed to relieve pressure from overcrowded stations. Overall, this study offers significant insights that can help planners in their task to design the systems of tomorrow, and similar undertakings can easily be imagined to other urban infrastructure systems (e.g., electricity grid, water/wastewater system, etc.) to develop more sustainable cities. PMID:22792373

  4. Dynamics of natural contamination by aluminium and iron rich colloids in the volcanic aquifers of Central Italy.

    Science.gov (United States)

    Viaroli, Stefano; Cuoco, Emilio; Mazza, Roberto; Tedesco, Dario

    2016-10-01

    The dynamics of natural contamination by Al and Fe colloids in volcanic aquifers of central-southern Italy were investigated. Localized perched aquifers, and their relative discharges, are strongly affected by the presence of massive suspended solids, which confer a white-lacteous coloration to the water. This phenomenon occasionally caused the interruption of water distribution due to the exceeding of Al and Fe concentrations in aquifers exploited for human supply. The cause was ascribed to water seepage from perched aquifers. Water discharges affected by such contamination was investigated for the Rocca Ripesena area (north-eastern sector of Vulsini Volcanic District) and for the Rianale Stream Valley (Roccamonfina Volcanic Complex). Hydrogeological survey of both areas confirmed the presence of perched aquifers not previously considered due to their low productivity. Pluviometric data and chemical parameters were periodically monitored. Water mineralization decreased with increasing rainfall, conversely Al and Fe concentrations increased. Statistical analysis confirmed the dependence of all the chemical variables on rock leaching, with the sole exception of Al and Fe which were imputed to colloids mobilization from local, strongly pedogenized pyroclastic material. The similarities in hydrogeological settings and mobilization dynamics in both areas suggest that the Al and Fe colloidal contamination should be more abundant than currently known in quaternary volcanic areas.

  5. Bromine release during Plinian eruptions along the Central American Volcanic Arc

    Science.gov (United States)

    Hansteen, T. H.; Kutterolf, S.; Appel, K.; Freundt, A.; Perez-Fernandez, W.; Wehrmann, H.

    2010-12-01

    Volcanoes of the Central American Volcanic Arc (CAVA) have produced at least 72 highly explosive eruptions within the last 200 ka. The eruption columns of all these “Plinian” eruptions reached well into the stratosphere such that their released volatiles may have influenced atmospheric chemistry and climate. While previous research has focussed on the sulfur and chlorine emissions during such large eruptions, we here present measurements of the heavy halogen bromine by means of synchrotron radiation induced micro-XRF microanalysis (SR-XRF) with typical detection limits at 0.3 ppm (in Fe rich standard basalt ML3B glass). Spot analyses of pre-eruptive glass inclusions trapped in minerals formed in magma reservoirs were compared with those in matrix glasses of the tephras, which represent the post-eruptive, degassed concentrations. The concentration difference between inclusions and matrix glasses, multiplied by erupted magma mass determined by extensive field mapping, yields estimates of the degassed mass of bromine. Br is probably hundreds of times more effective in destroying ozone than Cl, and can accumulate in the stratosphere over significant time scales. Melt inclusions representing deposits of 22 large eruptions along the CAVA have Br contents between 0.5 and 13 ppm. Br concentrations in matrix glasses are nearly constant at 0.4 to 1.5 ppm. However, Br concentrations and Cl/Br ratios vary along the CAVA. The highest values of Br contents (>8 ppm) and lowest Cl/Br ratios (170 to 600) in melt inclusions occur across central Nicaragua and southern El Salvador, and correlate with bulk-rock compositions of high Ba/La > 85 as well as low La/Yb discharged 700 kilotons of Br. On average, each of the remaining 21 CAVA eruptions studied have discharged c.100 kilotons of bromine. During the past 200 ka, CAVA volcanoes have emitted a cumulative mass of 3.2 Mt of Br through highly explosive eruptions. There are six periods in the past (c. 2ka, 6ka, 25ka, 40ka, 60ka, 75

  6. Crustal recycling by subduction erosion in the central Mexican Volcanic Belt

    Science.gov (United States)

    Straub, Susanne M.; Gómez-Tuena, Arturo; Bindeman, Ilya N.; Bolge, Louise L.; Brandl, Philipp A.; Espinasa-Perena, Ramón; Solari, Luigi; Stuart, Finlay M.; Vannucchi, Paola; Zellmer, Georg F.

    2015-10-01

    Recycling of upper plate crust in subduction zones, or 'subduction erosion', is a major mechanism of crustal destruction at convergent margins. However, assessing the impact of eroded crust on arc magmas is difficult owing to the compositional similarity between the eroded crust, trench sediment and arc crustal basement that may all contribute to arc magma formation. Here we compare Sr-Nd-Pb-Hf and trace element data of crustal input material to Sr-Nd-Pb-Hf-He-O isotope chemistry of a well-characterized series of olivine-phyric, high-Mg# basalts to dacites in the central Mexican Volcanic Belt (MVB). Basaltic to andesitic magmas crystallize high-Ni olivines that have high mantle-like 3He/4He = 7-8 Ra and high crustal δ18Omelt = +6.3-8.5‰ implying their host magmas to be near-primary melts from a mantle infiltrated by slab-derived crustal components. Remarkably, their Hf-Nd isotope and Nd/Hf trace element systematics rule out the trench sediment as the recycled crust end member, and imply that the coastal and offshore granodiorites are the dominant recycled crust component. Sr-Nd-Pb-Hf isotope modeling shows that the granodiorites control the highly to moderately incompatible elements in the calc-alkaline arc magmas, together with lesser additions of Pb- and Sr-rich fluids from subducted mid-oceanic ridge basalt (MORB)-type altered oceanic crust (AOC). Nd-Hf mass balance suggests that the granodiorite exceeds the flux of the trench sediment by at least 9-10 times, corresponding to a flux of ⩾79-88 km3/km/Myr into the subduction zone. At an estimated thickness of 1500-1700 m, the granodiorite may buoyantly rise as bulk 'slab diapirs' into the mantle melt region and impose its trace element signature (e.g., Th/La, Nb/Ta) on the prevalent calc-alkaline arc magmas. Deep slab melting and local recycling of other slab components such as oceanic seamounts further diversify the MVB magmas by producing rare, strongly fractionated high-La magmas and a minor population of

  7. Late Neoproterozoic Nuqara Dokhan Volcanics, Central Eastern Desert, Egypt: Geochemistery and petrogenesis

    Science.gov (United States)

    Hassan, Tharwat; Asran, Asran; Amron, Taha; Natflos, Theo

    2014-05-01

    The Nuqara volcanic is one of the northernmost outcrops of the Arabian-Nubian Shield Dokhan volcanics. The origin and tectonic setting of the late Neoproterozoic Dokhan volcanics (ca. 610-560 Ma) in the Egyptian Eastern Desert is highly debated. The debate concerns the tectonic setting where they formed during transition between convergent to extensional regime or after the East- and the West-Gondwana collision (~600Ma). In order to solve this problem, lavas from Nuqara area were studied geologically and geochemically. Nuqara Dokhan volcanics comprises two main rock suites: (a) an intermediate volcanic suite, consisting of basaltic andesite, andesite and their associated pyroclastics rocks; and (b) a felsic volcanic suite composed of dacite, rhyolite and ignimbrites. The two suites display well-defined major and trace element trends and continuum in composition with wide ranges in SiO2 (52-75.73%), CaO (9.19-0.22%), MgO (5.29-0.05%), Sr (1367-7.4 ppm), Zr (688.5-172.7 ppm), Cr (207-0.4 ppm), and Ni (94.3-0.2 ppm). The Nuqara Dokhan volcanics are characterized by strong enrichment in LILE relative to HFSE and affiliated to the calc-alkaline subducted - related magmatism. Geochemical Modeling displays that the evolution of these rocks was governed by fractional crystallization of plagioclase, amphiboles, pyroxene, magnetite and apatite in the intermediate varieties and plagioclase, amphibole, magnetite, apatite and zircon in the felsic varieties. The obtained mineral chemistry of these volcanics reveals: (a) Plagioclase range in composition from An55 to An40 in basaltic andesite and from An39 to An24 in andesite. (b) Alkali feldspars have sanidine composition. (c) Clinopyroxenes have augite composition. The low Al2O3 contents (1.94-5.588 wt %) indicate that clinopyroxene crystallized at low - pressure conditions. (d) Amphiboles have magnesio- hornblende composition.

  8. Network Centrality of Metro Systems

    OpenAIRE

    Sybil Derrible

    2012-01-01

    Whilst being hailed as the remedy to the world's ills, cities will need to adapt in the 21(st) century. In particular, the role of public transport is likely to increase significantly, and new methods and technics to better plan transit systems are in dire need. This paper examines one fundamental aspect of transit: network centrality. By applying the notion of betweenness centrality to 28 worldwide metro systems, the main goal of this paper is to study the emergence of global trends in the e...

  9. Seismic velocity structure of the central Taupo Volcanic Zone, New Zealand, from local earthquake tomography

    Science.gov (United States)

    Sherburn, Steven; Bannister, Stephen; Bibby, Hugh

    2003-03-01

    The 3-D distribution of P-wave velocity (Vp) and the P-wave/S-wave velocity ratio (Vp/Vs) are derived for the crust in the central Taupo Volcanic Zone (TVZ), New Zealand, by tomographic inversion of P- and S-wave arrival time data from local earthquakes. Resolution in the seismogenic mid-crust (4-6 km) is good, but poorer above and below these depths. The 3-D velocity model has several Vp anomalies as large as ±5% in the mid-lower crust (4-10 km) and more than ±10% in the upper crust (0-4 km). The model achieves a 55% reduction in data variance from an initial 1-D model. Young caldera structures, Okataina, Rotorua, and Reporoa, are characterised by low Vp anomalies at a depth of about 4 km and these coincide with large negative residual gravity anomalies. We attribute these anomalies to large volumes of low Vp, low-density, volcaniclastic sediments that have filled these caldera collapse structures. Although there are no Vp anomalies which suggest the presence of molten or semi-molten magma beneath the TVZ, a large, high Vp anomaly of more than +15% and a high Vp/Vs anomaly are observed coincident with a diorite pluton beneath the Ngatamariki geothermal field. However, Vp anomalies cannot be seen beneath the largest geothermal fields, Waimangu, Waiotapu, and Reporoa, and, consequently, if such anomalies exist, they must be below the resolution of our data. A prominent Vp contrast of 5-10% occurs at a depth of about 6 km beneath the boundary between the Taupo-Reporoa Depression and the Taupo Fault Belt (TFB), coincident with the eastern limit of the seismic activity beneath the TFB. We interpret this velocity contrast as being caused by the presence of extensive, non-molten, intrusives beneath the Taupo-Reporoa Depression. We suggest that the high-velocity material beneath the Taupo-Reporoa Depression is isolated from regional extension in the TVZ, and from the resulting faulting and seismicity, which occurs preferentially within the weaker material of the TFB. We

  10. Various origins of clinopyroxene megacrysts from basanites from the eastern part of Central European Volcanic Province

    Science.gov (United States)

    Lipa, Danuta; Puziewicz, Jacek; Ntaflos, Theodoros; Matusiak-Małek, Magdalena; Kukuła, Anna

    2014-05-01

    Clinopyroxene megacrysts up to few centimetres in size occur in Cenozoic alkaline lavas forming the north-eastern part of Central European Volcanic Province in Lower Silesia (SW Poland). The megacrysts occur, among other, in the Miocene basanite from Ostrzyca Proboszczowicka (bulk rock mg# 0.65-0.66) and in that from Lutynia (Pliocene, K-Ar age: 4.56 +/- 0.2 Ma; Birkenmajer et al. 2002; bulk rock mg# 0.64). The megacrysts typically consist of homogeneous core surrounded by patchy and spongy mantle, which is covered by a thin outermost rim of composition similar to that of the groundmass clinopyroxene occurring in the host basanite. The mantles of the megacrysts have been affected by melting, whereas the cores preserve their primary composition. We compare the core parts of megacrysts in the following. The Ostrzyca clinopyroxene megacrysts contain euhedral apatite intergrowths. The clinopyroxene has the composition of Fe-rich diopside (mg# = 0.61 - 0.70), contain significant sodium (to 0.12 a pfu) and are calcium rich (0.89-0.92 a pfu). The Lutynia megacrysts have the composition of augite and diopside (mg# 0.80-0.83). The sodium content is also high (to 0.12 a pfu), but calcium varies from 0.68 to 0.77 a pfu. The REE concentrations for Lutynia (1-10 x PM) are lower relative to Ostrzyca, enriched 10-100 times relative to PM. In both sites the megacrysts are strongly enriched in LREE relative to HREE and TE are characterized by positive Th, La and Ce anomalies, slight negative Sr and Y anomalies and strong Pb anomaly in the PM normalised patterns. The megacrysts from Ostrzyca reveal slight negative Ti and strong positive Zr and Hf anomalies, whereas those Lutynia have negative Zr anomaly and Ti anomaly is absent. Major and trace element composition shows that the megacrysts from Ostrzyca formed as coarse-grained cumulate at significant depth (lower crust?) from the LREE enriched alkaline melt. That melt was very rich in phosphorous which enabled its saturation in

  11. G-EVER Activities and the Next-generation Volcanic Hazard Assessment System

    Science.gov (United States)

    Takarada, S.

    2013-12-01

    The Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) is a consortium of Asia-Pacific geohazard research institutes that was established in 2012. G-EVER aims to formulate strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis and volcanic eruptions. G-EVER is working on enhancing collaboration, sharing of resources, and making information on the risks of earthquakes and volcanic eruptions freely available and understandable. The 1st G-EVER International Symposium was held in Tsukuba, Japan in March 11, 2013. The 2nd Symposium is scheduled in Sendai, Tohoku Japan, in Oct. 19-20, 2013. Currently, 4 working groups were proposed in the G-EVER Consortium. The next-generation volcano hazard assessment WG is developing a useful system for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is based on volcanic eruption history datasets, volcanic eruption database, and numerical simulations. Volcanic eruption histories including precursor phenomena leading to major eruptions of active volcanoes are very important for future prediction of volcanic eruptions. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and types, is important for the next-generation volcano hazard assessment system. Proposing international standards on how to estimate the volume of volcanic products is important to make a high quality volcanic eruption database. Spatial distribution database of volcanic products (e.g. tephra and pyroclastic flow distributions), encoded into a GIS based database is necessary for more precise area and volume estimation and risk assessments. The volcanic eruption database is developed based on past eruption results, which only represents a subset of possible future scenarios. Therefore, numerical simulations with controlled parameters are needed for more precise volcanic eruption

  12. Does Students' Source of Knowledge Affect Their Understanding of Volcanic Systems?

    Science.gov (United States)

    Parham, Thomas L.; Cervato, Cinzia; Gallus, William; Larsen, Michael; Hobbs, Jon; Greenbowe, Thomas

    2011-01-01

    A recent survey of undergraduates at five schools across the United States indicates that many undergraduates feel that they have learned more about volcanic systems from Hollywood films and the popular media than they learned in the course of their precollegiate formal education. Scores on the Volcanic Concept Survey, an instrument designed to…

  13. Fluorine in the rocks and sediments of volcanic areas in central Italy: total content, enrichment and leaching processes and a hypothesis on the vulnerability of the related aquifers.

    Science.gov (United States)

    De Rita, Donatella; Cremisini, Carlo; Cinnirella, Alessandro; Spaziani, Fabio

    2012-09-01

    Rock, sediment and water samples from areas characterised by hydrothermal alterations in the Sabatini and Vico Volcanic Districts, near Rome and the large city of Viterbo, respectively, were collected and analysed to determine the total fluorine (F) content and to understand the F geochemical background level in the volcanic districts of central Italy. Leaching and alteration processes controlling the high concentration of F in water were also investigated. Fluorine concentrations were directly determined (potentiometrically) by an F selective electrode in water samples, while the procedure for rock samples included preliminary F dissolution through alkaline fusion. F concentrations higher than 800 mg kg(-1) were commonly found in the analysed rocks and sediments; the concentration depended on the lithology and on the distance from the alteration areas. A specific successive sampling campaign was conducted in three areas where the F content in sediments was particularly high; in the same areas, measurements of CO(2) flux were also performed to investigate the possible deep origin of F. To verify the relationships among the high F contents in rocks and sediments, the leaching processes involved and the presence of F in the aquifer, we also collected water samples in the western sector of the Sabatini Volcanic District, where hydrothermal manifestations and mineral springs are common. The data were processed using a GIS system in which the F distribution was combined with morphological and geological observations. The main results of our study are that (1) F concentrations are higher in volcanic and recently formed travertine (especially in hydrothermally altered sediments) than in sedimentary rocks and decrease with distance from hydrothermal alteration areas, (2) F is more easily leached from hydrothermally altered rocks and from travertine and (3) sediments enriched with F may indicate the presence of deep regional fractures that represent direct pathways of

  14. Eruptive history, petrology, and petrogenesis of the Joe Lott Tuff Member of the Mount Belknap Volcanics, Marysvale volcanic field, west-central Utah

    Science.gov (United States)

    Budding, Karin E.

    1982-01-01

    The Joe Lott Tuff Member of the Mount Belknap Volcanics is the largest rhyolitic ash-flow tuff sheet in the Marysvale volcanic field. It was erupted 19 m.y. ago, shortly after the changeover from intermediate-composition calc-alkalic volcanism to bimodal basalt-rhyolite volcanism. Eruption of the tuff resulted in the formation of the Mount Belknap Caldera whose pyroclastic intracaldera stratigraphy parallels that in the outflow facies. The Joe Loft Tuff Member is a composite ash-flow sheet that changes laterally from a simple cooling unit near the source to four distinct cooling units toward the distal end. The lowest of these units is the largest and most widespread; it is 64 m thick and contains a basal vitrophyre. Eruption of the lower unit led to the initial collapse of the caldera. The lower unit is followed upward by a 43 m middle unit, a 26 m pink-colored unit which is separated by a prominent air- fall layer, and a 31 m upper unit. The Joe Loft Tuff Member is an alkali rhyolite with 75.85-77.31 wt. % silica and 8.06-9.32 wt. % K2O+Na2O; the agpaitic index (Na2O+ K2O/Al2O3) is .77-.98. The tuff contains about I% phenocrysts of quartz, sanidine, oligoclase, augite, apatite, zircon, sphene, biotite, and oxidized Fe-Ti oxides. The basal vitrophyre contains accessory allanite, chevkinite, and magnesiohastingsite. The main cooling units are chemically and mineralogically zoned indicating that the magma chamber restratified prior to each major eruption. Within each of the two thickest cooling units, the mineralogy changes systematically upwards; the Or content and relative volume of sanidine decreases and An content of plagioclase increases. The basal vitrophyre of the lower unit has a bulk composition that lies in the thermal trough near the minima of Or-Ab-Q at 1 kb PH2O. Microprobe analyses of feldspar and chemical modeling on experimental systems indicate that pre-eruption temperatures were near 750?C and that the temperature increased during the eruption of

  15. PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA

    Directory of Open Access Journals (Sweden)

    S.S. Anvari

    2009-08-01

    Full Text Available ObjectivePrimary central nervous system lymphoma (PCNSL is an extremely rare condition in childhood. We report the first case of PCNSL in a child in Iran.Clinical presentationA nine-year-old boy was referred to Mofid Hospital with the history of headache of four months and seizure of 2 months duration. Magnetic resonance imaging of the brain revealed a hyper-intense lesion in left fronto-parietal area with secondary satellite lesions. Biopsy of the brain mass was performed. Pathologic findings showed brain lymphoma and immunohistochemistry confirmed this diagnosis. The treatment started with intrathecal and systemic chemotherapy in combination with radiotherapy.Keywords:Lymphoma, Primary central nervous system lymphoma (PCNSL, Children

  16. Volcano-tectonics of the Al Haruj Volcanic Province, Central Libya

    Science.gov (United States)

    Elshaafi, Abdelsalam; Gudmundsson, Agust

    2016-10-01

    The Al Haruj intra-continental Volcanic Province (AHVP), located at the south-western margin of the Sirt Basin, hosts the most extensive and recent volcanic activity in Libya - which is considered typical for plate interiors. From north to south the AHVP is divided into two subprovinces, namely Al Haruj al Aswad and Al Haruj al Abiyad. The total area of the AHVP is around 42,000 km2. Despite the great size of the AHVP, its volcano-tectonic evolution and activity have received very little attention and are poorly documented and understood. Here we present new field data, and analytical and numerical results, on the volcano-tectonics of the AHVP. The length/thickness ratio of 47 dykes and volcanic fissures were measured to estimate magmatic overpressure at the time of eruption. The average dyke (length/thickness) ratio of 421 indicates magmatic overpressures during the associate fissure eruptions of 8-19 MPa (depending on host-rock elastic properties). Spatial distributions of 432 monogenetic eruptions sites/points (lava shields, pyroclastic cones) in the AHVP reveal two main clusters, one in the south and another in the north. Aligned eruptive vents show the dominating strike of volcanic fissures/feeder-dykes as WNW-ESE to NW-SE, coinciding with the orientation of one of main fracture/fault zones. Numerical modelling and field observations suggest that some feeder-dykes may have used steeply dipping normal-fault zones as part of their paths to the surface.

  17. Middle Triassic volcanic rocks in the Northern Qiangtang (Central Tibet): Geochronology, petrogenesis, and tectonic implications

    Science.gov (United States)

    Chen, Sheng-Sheng; Shi, Ren-Deng; Yi, Guo-Ding; Zou, Hai-Bo

    2016-01-01

    Although voluminous magmatism occurred during the Triassic in the Qiangtang terrane, the petrogenesis of the volcanic rocks and the associated tectonic scenarios remain mysterious. This study focuses on new identified primitive volcanic rocks from the Yanshiping area, Northern Qiangtang subterrane. The whole-rock major-trace elemental, Sr-Nd isotopic data, and zircon U-Pb age of volcanic rocks are reported in this paper in order to understand their petrogenesis and tectonic setting. The studied volcanic rocks can be grouped into two types, i.e., Nb-enriched basalts and basaltic andesites (NEBs) in the low sequence and arc basalts in the upper sequence. Zircon U-Pb dating using LA-ICP-MS techniques yields the concordant age with a weighted mean 206Pb/238U age of ca. 242-241 Ma for the NEBs and ca. 240 Ma for the arc basalts. The distinct geochemical and isotopic characteristics of whole-rock and varying Th-U-REE components of zircon grains from the volcanic rocks suggest that the NEBs were derived from partial melting of relatively enriched mantle wedge that have been metasomatised by slab-related melts and that the arc basalts originated from partial melting of mixing of mantle wedge and depleted asthenospheric mantle in response to the slab breakoff. Our new geochemical and geochronological results, in combination with regional studies, imply that the Middle Triassic magmatism was generated in the tectonic setting of northward subduction of the Paleo-Tethys or Bangong-Nujiang Ocean. Subduction-related processes that include melting of the slab and the slab breakoff during the Permian-Middle Triassic made an important contribution to crustal growth in the Qiangtang terrane, whereas vertical crustal growth associated with collision-related setting during the Late Triassic is nonsignificant.

  18. Geochronology and magmatic evolution of the Dieng Volcanic Complex, Central Java, Indonesia and their relationships to geothermal resources

    Science.gov (United States)

    Harijoko, Agung; Uruma, Ryusuke; Wibowo, Haryo Edi; Setijadji, Lucas Doni; Imai, Akira; Yonezu, Kotaro; Watanabe, Koichiro

    2016-01-01

    We analyzed new radiometric dating and petrological data of DVC in an attempt to reconstruct volcanic history as groundwork to understand magmatic temporal and spatial evolution. The magma of DVC can be divided on the basis of mineral composition into three types: olivine bearing basalt-basaltic andesite, pyroxene basaltic andesite-andesite, and biotite andesite-dacite, which coincide with three volcanic episodes of DVC: pre-caldera, second, and youngest episode, respectively. The pre-caldera episode was active no later than 1 Ma, the second episode occurred between 0.3 and 0.4 Ma, and the youngest occurred after 0.27 Ma. Plots of CaO, K2O, Al2O3, and Rb/Sr against FeO*/MgO and/or MgO suggest that each volcanic episode has distinct differentiation trends, indicating the presence of multiple shallow magma chambers. The close spatial relationship between the geothermal manifestation, geophysical anomalies, geothermal production zones and volcanic edifices supports the presence of multiple shallow magma chambers beneath DVC, which act as a heat source for the existing geothermal system.

  19. Tectonics Along Western-Central Part of the Trans Mexican Volcanic Belt as Inferred From Palaeomagnetic Data: A Summary

    Science.gov (United States)

    Rosas-Elguera, J.; Goguichaisvilli, A.; Alva-Valdivia, L.; Urrutia-Fucugauchi, J.

    2007-05-01

    The Trans-Mexican Volcanic Belt (TMVB), one of the largest continental volcanic arcs built on the North America plate, spans about 1000 km and crosses central Mexico from the Pacific Ocean to the Gulf of Mexico. The initial stage of the TMVB is marked by widespread Miocene basaltic volcanism, emplaced from the Nayarit state, in the west, to the longitude of Mexico City. This volcanism is characterized by plateau-like structures resulting from the shield volcanoes and fissure lava flows, which have an estimated aggregate volume ranging between 3200 and 6800 km3. The western-central Mexico has been affected by right-lateral transtension within the western TMVB but previous paleomagnetic studies indicate some 15-20° anticlockwise tectonic rotations for the Rio Grande de Santiago canyon and surrounding areas, in accordance with a Miocene left-lateral transtensional tectonic regime. We present a summary of paleomagnetic and rock-magnetic studies of that Miocene volcanic succession from the TMVB. A total of 114 consecutive basaltic lava flows (more than 550 oriented samples) were collected from four localities: Tepic, Guadalajara, Los Altos, and Queretaro which span from 11 to 7.5 Ma. The mean paleodirection obtained for Tepic area is I = 33.7°, D = 358.4°, k = 140, á95 = 3.0°, N = 17. These directions are in perfect agreement with the expected paleodirections for late Miocene time, as derived from reference poles given by Besse and Courtillot (1991) for North America.. The mean paleodirection obtained for Guadalajara is I = 31.1°, D = 354.6°, k = 124, 95 = 2.1°, which corresponds to the mean paleomagnetic pole position Plat = 84°, Plong = 129.8°, k = 29, 95 = 4.4°. These directions are in reasonably good agreement with the expected paleodirections for middle Miocene time. The mean paleomagnetic direction calculated for Los Altos and Queretaro is I = 32.46°, D = 341.2°, k = 7.2 and 95 = 11.6°. Thus, our results suggest that no major block rotation has

  20. The ~ 2000 yr BP Jumento volcano, one of the youngest edifices of the Chichinautzin Volcanic Field, Central Mexico

    Science.gov (United States)

    Arce, J. L.; Muñoz-Salinas, E.; Castillo, M.; Salinas, I.

    2015-12-01

    The Chichinautzin Volcanic Field is situated at the southern limit of the Basin of Mexico and the Metropolitan area of Mexico City, the third most populated city around the world. The Chichinautzin Volcanic field holds more than 220 monogenetic volcanoes. Xitle is the youngest of these with an estimated age of 1.6 ky BP. Xitle's eruptive activity took place during the Mesoamerican Mexican Pre-classic period and is related to the destruction of Cuicuilco Archaeological Site, the oldest civilization known in Central Mexico. However, there are still several regional cones that have not been dated. Based on 14C ages, stratigraphic and geomorphologic criteria, we conclude that the Jumento volcano, located to the west of Xitle, is one of the youngest cones of the Chichinautzin Volcanic Field. The Jumento volcano has a basaltic andesite composition, and its eruptive activity was initially hydromagmatic, followed by Strombolian and finally effusive events occurred recorded through: (1) a sequence of hydromagmatic pyroclastic surges and ashfall layers emplaced at a radius of > 5 km from the crater with charcoal fragments at its base; this activity built the Jumento's cone with slopes of 32°; and (2) lava flows that breached the southern part of the cone and flowed for up to 2.5 km from the vent. The resulting 14C ages for this volcano yielded a maximum age of ~ 2 ky BP. Morphometric analysis indicates that the state of degradation of Jumento cone is similar to the Xitle, suggesting that the Jumento could be in the state of degradation of a volcanic structure of similar age or younger adding credence to the probable radiocarbon age of ~ 2 ky BP for the Jumento edifice.

  1. The hydrothermal system of Volcan Puracé, Colombia

    Science.gov (United States)

    Sturchio, Neil C.; Williams, Stanley N.; Sano, Yuji

    1993-05-01

    This paper presents chemical and isotopic data for thermal waters, gases and S deposits from Volcan Puracé (summit elevation ˜4600 m) in SW Colombia. Hot gas discharges from fumaroles in and around the summit crater, and thermal waters discharge from three areas on its flanks. The waters from all areas have δD values of-75±1, indicating a single recharge area at high elevation on the volcano. Aircorrected values of3He/4He in thermal waters range from 3.8 to 6.7 RA, and approach those for crater fumarole gas (6.1 7.1 RA), indicating widespread addition of magmatic volatiles. An economic S deposit (El Vinagre) is being mined in the Rio Vinagre fault zone at 3600 m elevation. Sulfur isotopic data are consistent with a magmatic origin for S species in thermal waters and gases, and for the S ore deposit. Isotopic equilibration between S species may have occurred at 220±40°C, which overlaps possible equilibration temperatures (170±40°C) determined by a variety of other geothermometers for neutral thermal waters. Apparent CH4-CO2 equilibration temperatures for gases from thermal springs (400±50°C) and crater fumaroles (520±60°C) reflect higher temperatures deeper in the system. Hot magmatic gas ascending through the Rio Vinagre fault zone is though to have precipitated S and generated thermal waters by interaction with descending meteoric waters.

  2. Petrology and petrogenesis of the Eocene Volcanic rocks in Yildizeli area (Sivas), Central Anatolia, Turkey

    Science.gov (United States)

    Doğa Topbay, C.; Karacık, Zekiye; Genç, S. Can; Göçmengil, Gönenç

    2015-04-01

    Yıldızeli region to the south of İzmir Ankara Erzincan suture zone is situated on the large Sivas Tertiary sedimentary basin. After the northern branch of the Neotethyan Ocean was northerly consumed beneath the Sakarya Continent, a continent - continent collision occurred between the Anatolide- Tauride platform and Pontides and followed a severe intermediate magmatism during the Late Cretaceous- Tertiary period. This created an east-west trending volcanic belt along the whole Pontide range. In the previous studies different models are suggested for the Eocene volcanic succession such as post-collisional, delamination and slab-breakoff models as well as the arc model for its westernmost parts. We will present our field and geochemical data obtained from the Yıldızeli and its surroundings for its petrogenesis, and will discuss the tectonic model(s) on the basis of their geochemical/petrological aspects. Cenozoic volcanic sequences of Yıldızeli region which is the main subject of this study, overlie Pre-Mesozoic crustal meta-sedimentary group of Kırşehir Massif, Ophiolitic mélange and Cretaceous- Paleocene? flysch-like sequences. In the northern part of Yıldızeli region, north vergent thrust fault trending E-W seperates the ophiolitic mélange complex from the Upper Cretaceous-Paleocene and Tertiary formations. Volcano-sedimentary units, Eocene in age, of the Yıldızeli (Sivas-Turkey) which are intercalated with sedimentary deposits related to the collision of Anatolide-Tauride and a simultaneous volcanic activity (i.e. the Yıldızeli volcanics), exposed throughout a wide zone along E-W orientation. Yıldızeli volcanics consist of basalts, basaltic-andesites and andesitic lavas intercalated flow breccias and epiclastic, pyroclastic deposits. Basaltic andesite lavas contain Ca-rich plagioclase + clinopyroxene ± olivine with minor amounts of opaque minerals in a matrix comprised of microlites and glass; andesitic lavas are generally contain Ca

  3. The lower cretaceous volcanism in the coastal range of Central Chile: Geochronology and isotopic geochemistry

    International Nuclear Information System (INIS)

    Major factors involved in subduction zone magmatism are related to the melting of the underlying mantle, which can contain a component of aqueous fluid and/or melts derived from the subducting plate (e.g. Peate et al., 1997). The Chilean Pacific margin is a subduction zone, active from Early Mesozoic to now, in which the magmatic arc emplaced on the Paleozoic basement progressively migrate to the east. The western part of this arc constitutes the Coastal Range. In this work, isotopic and radiometric data from four E-W profiles along c. 500 km of the Lower Cretaceous volcanic rocks in the Coastal Range of Chile are presented. The aim of this research is to obtain a model for the genesis of this Cretaceous volcanic arc based on their isotopic signature (au)

  4. Chemistry of ash-leachates to monitor volcanic activity: An application to Popocatepetl volcano, central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Armienta, M.A., E-mail: victoria@geofisica.unam.mx [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico); De la Cruz-Reyna, S. [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico); Soler, A. [Grup de Mineralogia Aplicada i Medi Ambient, Dep. Cristal.lografia, Mineralogia i Diposits Minerals, Fac. Geologia, Universidad de Barcelona (Spain); Cruz, O.; Ceniceros, N.; Aguayo, A. [Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Circuito Exterior, C.U., Mexico 04510 D.F. (Mexico)

    2010-08-15

    Monitoring volcanic activity and assessing volcanic risk in an on-going eruption is a problem that requires the maximum possible independent data to reduce uncertainty. A quick, relatively simple and inexpensive method to follow the development of an eruption and to complement other monitoring parameters is the chemical analysis of ash leachates, particularly in the case of eruptions related to dome emplacement. Here, the systematic analysis of SO{sub 4}{sup 2-}, Cl{sup -} and F{sup -} concentrations in ash leachates is proposed as a valuable tool for volcanic activity monitoring. However, some results must be carefully assessed, as is the case for S/Cl ratios, since eruption of hydrothermally altered material may be confused with degassing of incoming magma. Sulfur isotopes help to identify SO{sub 4} produced by hydrothermal processes from magmatic SO{sub 2}. Lower S isotopic values correlated with higher F{sup -} percentages represent a better indicator of fresh magmatic influence that may lead to stronger eruptions and emplacement of new lava domes. Additionally, multivariate statistical analysis helps to identify different eruption characteristics, provided that the analyses are made over a long enough time to sample different stages of an eruption.

  5. Tracking changes in volcanic systems with seismic Interferometry

    Science.gov (United States)

    Haney, Matt; Alicia J. Hotovec-Ellis,; Ninfa L. Bennington,; Silvio De Angelis,; Clifford Thurber,

    2014-01-01

    The detection and evaluation of time-dependent changes at volcanoes form the foundation upon which successful volcano monitoring is built. Temporal changes at volcanoes occur over all time scales and may be obvious (e.g., earthquake swarms) or subtle (e.g., a slow, steady increase in the level of tremor). Some of the most challenging types of time-dependent change to detect are subtle variations in material properties beneath active volcanoes. Although difficult to measure, such changes carry important information about stresses and fluids present within hydrothermal and magmatic systems. These changes are imprinted on seismic waves that propagate through volcanoes. In recent years, there has been a quantum leap in the ability to detect subtle structural changes systematically at volcanoes with seismic waves. The new methodology is based on the idea that useful seismic signals can be generated “at will” from seismic noise. This means signals can be measured any time, in contrast to the often irregular and unpredictable times of earthquakes. With seismic noise in the frequency band 0.1–1 Hz arising from the interaction of the ocean with the solid Earth known as microseisms, researchers have demonstrated that cross-correlations of passive seismic recordings between pairs of seismometers yield coherent signals (Campillo and Paul 2003; Shapiro and Campillo 2004). Based on this principle, coherent signals have been reconstructed from noise recordings in such diverse fields as helioseismology (Rickett and Claerbout 2000), ultrasound (Weaver and Lobkis 2001), ocean acoustic waves (Roux and Kuperman 2004), regional (Shapiro et al. 2005; Sabra et al. 2005; Bensen et al. 2007) and exploration (Draganov et al. 2007) seismology, atmospheric infrasound (Haney 2009), and studies of the cryosphere (Marsan et al. 2012). Initial applications of ambient seismic noise were to regional surface wave tomography (Shapiro et al. 2005). Brenguier et al. (2007) were the first to

  6. Late Paleogene topography of the Central Rocky Mountains and western Great Plains region using hydrogen isotope ratios in volcanic glass

    Science.gov (United States)

    Rossetto, G.; Fricke, H. C.; Cassel, E. J.; Evanoff, E.

    2015-12-01

    The Central Rocky Mountains (CRM), located in southern Wyoming, Colorado, and northern New Mexico, are characterized by the highest elevation basins (up to 2500 m) and mountains (over 4000 m) in the North American Cordillera. The timing and drivers for surface uplift of the CRM have not been conclusively determined. The goal of this study is to constrain the timing of surface uplift of the CRM by comparing hydrogen isotope ratios of hydration waters (δDglass) in late Paleogene volcanic glasses preserved in felsic tuffs deposited in CRM basins to δDglass values from glasses of similar age (34.9 to 32.2 Ma) preserved in tuffs from the surrounding Great Plains. The tuffs deposited in the Great Plains, to the north and east of the CRM, are currently at elevations of 1100-1600 m. Volcanic glass hydrates shortly after deposition, preserving the δD of ancient meteoric water on geologic timescales, and can thus be used as a proxy for ancient precipitation δD values. Volcanic glasses from the CRM have δDglass values that are an average of ~31‰ higher than δDglass values from the Great Plains, while modern day precipitation δD values in the CRM are ~25‰ lower than δD values in the Great Plains. These results suggest that the uplift of the CRM relative to the surrounding Great Plains occurred after ~32 Ma. This requires a mechanism such as mantle upwelling or differential crustal hydration, not solely Laramide tectonism, to uplift the CRM to current elevations. Elevation, however, may not have been the only control on the spatial distribution of precipitation δD values across the western US. Similar to the modern, mixing of Pacific and Gulf coast air masses likely occurred during the latest Paleogene, driving regional variability in δD values of precipitation.

  7. Geology, thermal maturation, and source rock geochemistry in a volcanic covered basin: San Juan sag, south-central Colorado

    Science.gov (United States)

    Gries, R.R.; Clayton, J.L.; Leonard, C.

    1997-01-01

    The San Juan sag, concealed by the vast San Juan volcanic field of south-central Colorado, has only recently benefited from oil and gas wildcat drilling and evaluations. Sound geochemical analyses and maturation modeling are essential elements for successful exploration and development. Oil has been produced in minor quantities from an Oligocene sill in the Mancos Shale within the sag, and major oil and gas production occurs from stratigraphically equivalent rocks in the San Juan basin to the south-west and in the Denver basin to the northeast. The objectives of this study were to identify potential source rocks, assess thermal maturity, and determine hydrocarbon-source bed relationships. Source rocks are present in the San Juan sag in the upper and lower Mancos Shale (including the Niobrara Member), which consists of about 666 m (2184 ft) of marine shale with from 0.5 to 3.1 wt. % organic carbon. Pyrolysis yields (S1 + S2 = 2000-6000 ppm) and solvent extraction yields (1000-4000 ppm) indicate that some intervals within the Mancos Shale are good potential source rocks for oil, containing type II organic matter, according to Rock-Eval pyrolysis assay. Oils produced from the San Juan sag and adjacent part of the San Juan basin are geochemically similar to rock extracts obtained from these potential source rock intervals. Based on reconstruction of the geologic history of the basin integrated with models of organic maturation, we conclude that most of the source rock maturation occurred in the Oligocene and Miocene. Little to no maturation took place during Laramide subsidence of the basin, when the Animas and Blanco Basin formations were deposited. The timing of maturation is unlike that of most Laramide basins in the Rocky Mountain region, where maturation occurred as a result of Paleocene and Eocene basin fill. The present geothermal gradient in the San Juan sag is slightly higher (average 3.5??C/100 m; 1.9??F/100 ft) than the regional average for southern Rocky

  8. Late Cenozoic calc-alkaline volcanism over the Payenia shallow subduction zone, South-Central Andean back-arc (34°30‧-37°S), Argentina

    Science.gov (United States)

    Litvak, Vanesa D.; Spagnuolo, Mauro G.; Folguera, Andrés; Poma, Stella; Jones, Rosemary E.; Ramos, Víctor A.

    2015-12-01

    A series of mesosilicic volcanic centers have been studied on the San Rafael Block (SRB), 300 km to the east of the present-day volcanic arc. K-Ar ages indicate that this magmatic activity was developed in at least two stages: the older volcanic centers (˜15-10 Ma) are located in the central and westernmost part of the SRB (around 36°S and 69°W) and the younger centers (8-3.5 Ma) are located in an eastern position (around 36°S and 69°30‧W) with respect to the older group. These volcanic rocks have andesitic to dacitic compositions and correspond to a high-K calc-alkaline sequence as shown by their SiO2, K2O and FeO/MgO contents. Elevated Ba/La, Ba/Ta and La/Ta ratios show an arc-like signature, and primitive mantle normalized trace element diagrams show typical depletions of high field strength elements (HFSE) relative to large ion lithophile elements (LILE). Rare earth element (REE) patterns suggest pyroxene and amphibole crystallization. Geochemical data obtained for SRB volcanic rocks support the proposal for a shallow subduction zone for the latest Miocene between 34°30″-37°S. Regionally, SRB volcanism is associated with a mid-Miocene to early Pliocene eastward arc migration caused by the shallowing of the subducting slab in the South-Central Andes at these latitudes, which represents the evolution of the Payenia shallow subduction segment. Overall, middle Miocene to early Pliocene volcanism located in the Payenia back-arc shows evidence for the influence of slab-related components. The younger (8-3.5 Ma) San Rafael volcanic rocks indicate the maximum slab shallowing and the easternmost extent of slab influence in the back-arc.

  9. Group II Xenoliths from Lunar Crater Volcanic Field, Central Nevada: Evidence for a Kinked Geotherm

    Science.gov (United States)

    Roden, M.; Mosely, J.; Norris, J.

    2015-12-01

    Group II xenoliths associated with the 140 Ka Easy Chair Crater, Lunar Crater volcanic field, NV, consist of amphibole rich-inclusions including amphibolites, pyroxenites, and gabbros. Abundant minerals in these inclusions are kaersutite, aluminous (7.3-9.7 wt% Al2O3), calcic clinopyroxene, primarily diopside, and olivine (Mg# 69-73) with accessory spinel, sulfide and apatite. Although most apatites are fluor-hydroxyapatite solid solutions, one xenolith contains Cl- and OH-rich apatite suggesting that Cl may have been an important constituent in the parent magma(s) . The xenoliths show abundant evidence for equilibration at relatively low temperatures including amphibole and orthopyroxene exsolution in clinopyroxene, and granules of magnetite in hercynite hosts. If latter texture is due to exsolution, then this particular Group II xenolith equilibrated at temperatures near or below 500oC or at a depth of about 15 km along a conductive geotherm. It may be that all the Group II xenoliths equilibrated at low temperatures given the abundant exsolution textures although Fe-Mg exchange relations suggest equilibration at temperatures in excess of 800oC. Low equilibration temperatures are in conflict with the unusually high equilibration temperatures, >1200oC (Smith, 2000) displayed by Group I xenoliths from this same volcanic field. Taken at face value, the geothermometric results indicate unusually high temperatures in the upper mantle, normal temperatures in the crust and the possibility of a kinked geotherm in the region. Curiously the LCVF lies in an area of "normal" heat flow, south of the Battle Mountain area of high heat flow but the number of heat flow measurements in the Lunar Crater area is very low (Humphreys et al., 2003; Sass, 2005). References: Humphreys et al., 2003, Int. Geol. Rev. 45: 575; Sass et al., 2005, http://pubs.usgs.gov/of/2005/1207/; Smith, 2000, JGR 105: 16769.

  10. Use of Low-Cost Acquisition Systems with an Embedded Linux Device for Volcanic Monitoring.

    Science.gov (United States)

    Moure, David; Torres, Pedro; Casas, Benito; Toma, Daniel; Blanco, María José; Del Río, Joaquín; Manuel, Antoni

    2015-08-19

    This paper describes the development of a low-cost multiparameter acquisition system for volcanic monitoring that is applicable to gravimetry and geodesy, as well as to the visual monitoring of volcanic activity. The acquisition system was developed using a System on a Chip (SoC) Broadcom BCM2835 Linux operating system (based on DebianTM) that allows for the construction of a complete monitoring system offering multiple possibilities for storage, data-processing, configuration, and the real-time monitoring of volcanic activity. This multiparametric acquisition system was developed with a software environment, as well as with different hardware modules designed for each parameter to be monitored. The device presented here has been used and validated under different scenarios for monitoring ocean tides, ground deformation, and gravity, as well as for monitoring with images the island of Tenerife and ground deformation on the island of El Hierro.

  11. Use of Low-Cost Acquisition Systems with an Embedded Linux Device for Volcanic Monitoring

    Directory of Open Access Journals (Sweden)

    David Moure

    2015-08-01

    Full Text Available This paper describes the development of a low-cost multiparameter acquisition system for volcanic monitoring that is applicable to gravimetry and geodesy, as well as to the visual monitoring of volcanic activity. The acquisition system was developed using a System on a Chip (SoC Broadcom BCM2835 Linux operating system (based on DebianTM that allows for the construction of a complete monitoring system offering multiple possibilities for storage, data-processing, configuration, and the real-time monitoring of volcanic activity. This multiparametric acquisition system was developed with a software environment, as well as with different hardware modules designed for each parameter to be monitored. The device presented here has been used and validated under different scenarios for monitoring ocean tides, ground deformation, and gravity, as well as for monitoring with images the island of Tenerife and ground deformation on the island of El Hierro.

  12. Late Mesozoic-Cenozoic intraplate magmatism in Central Asia and its relation with mantle diapirism: Evidence from the South Khangai volcanic region, Mongolia

    Science.gov (United States)

    Yarmolyuk, Vladimir V.; Kudryashova, Ekaterina A.; Kozlovsky, Alexander M.; Lebedev, Vladimir A.; Savatenkov, Valery M.

    2015-11-01

    The South Khangai volcanic region (SKVR) comprises fields of Late Mesozoic-Cenozoic volcanic rocks scattered over southern and central Mongolia. Evolution of the region from the Late Jurassic to the Late Cenozoic includes 13 successive igneous episodes that are more or less evenly distributed in time. Major patterns in the distribution of different-aged volcanic complexes were controlled by a systematic temporal migration of volcanic centers over the region. The total length of their trajectory exceeds 1600 km. Principle characteristics of local magmatism are determined. The composition of igneous rocks varies from basanites to rhyolites (predominantly, high-K rocks), with geochemistry close to that of OIB. The rock composition, however, underwent transformations in the Mesozoic-Cenozoic. Rejuvenation of mafic rocks is accompanied by decrease in the contents of HREE and increase of Nb and Ta. According to isotope data, the SKVR magmatic melts were derived from three isotope sources that differed in the Sr, Nd, and Pb isotopic compositions and successively alternated in time. In the Early Cretaceous, the predominant source composition was controlled by interaction of the EMII- and PREMA-type mantle materials. The PREMA-type mantle material dominated quantitatively in the Late Cretaceous and initial Early Cenozoic. From the latest Early Cenozoic to Late Cenozoic, the magma source also contained the EMI-type material along with the PREMA-type. The structural fabric, rock composition, major evolutionary pattern, and inner structure of SKVR generally comply with the criteria used to distinguish the mantle plume-related regions. Analogous features can be seen in other regions of recent volcanism in Central Asia (South Baikal, Udokan, Vitim, and Tok Stanovik). The structural autonomy of these regions suggests that distribution of the Late Mesozoic-Cenozoic volcanism in Central Asia was controlled by a group of relatively small hot finger-type mantle plumes associated with

  13. Magma types and mantle sources of the Bárðarbunga volcanic system, Iceland

    Science.gov (United States)

    Halldórsson, Sæmundur; Rubin, Ken; Sverrisdóttir, Guðrún; Sigurðsson, Gylfi

    2015-04-01

    The Bárðarbunga volcanic system (BVS) represents one of the largest volcanic systems in Iceland, extending ~190 km from the northern boundary of Torfajökull in the south to Dyngjufjöll Ytri in the north, and intersecting the largely ice-covered Bárðarbunga volcano. The extensive length of the BVS thus allows sampling of an unusually large section of the mantle underlying Iceland's Eastern rift zone. Perhaps surprisingly, the degree of mantle source heterogeneity beneath the BVS remains poorly known. We have recently undertaken a detailed study of the BVS because such data are fundamental for understanding the magmatic history and magma delivery system beneath of the BVS, including those that led to recent volcanism north of Dyngjujökull. Here, we present major and trace element analyses, as well as high-precision Pb isotope analyses, of several Holocene lava flows from the Dyngjuháls area and from rocks representing the basement, flanks and nunataks of the ice-free part of the Bárðarbunga volcano. We compare these data to those on a suite of recently collected fissure basalts from the Veiðivötn fissure swarm in the south and the new lava north of Dyngjujökull in order to study the geochemical characteristics of the BVS as a whole. The BVS has generated fairly primitive tholeiites (MgO ~6-9 wt.%) throughout the Holocene. Evolved basaltic compositions (MgO ≤6 wt.%) that are often associated with large and mature caldera systems in Iceland (e.g., Krafla and Askja), appear to be notably absent in the BVS within our current sample set (although might still exist in the largely ice-covered Bárðarbunga volcano). Significantly, no highly evolved rocks (dacite, rhyolite) have been associated with the BVS. It is therefore unlikely that a long-lived and relatively shallow (18.40. In contrast, subglacial formations in the Dyngjuháls region, form a single trend with 206Pb/204Pb always melts to the BVS, in different proportions in space and time. However

  14. Small-scale volcanic landforms indicative of distributary tube systems

    Science.gov (United States)

    Theilig, E.

    1988-01-01

    Surface features tens to hundreds of meters in size on Martian lava flows are revealed in high resolution Viking Orbiter images. Many of these morphological features form in response to certain flow emplacement mechanisms, eruptive styles, or rheological properties of the lava. Insight into the relationships between lava flow morphology and the emplacement and characteristics of magma is an ongoing areas of research and allows constraints to be placed on interpretation of Martian volcanism. This report focuses on pressure ridges, tumuli, and pressure plateaus which comprise a suite fo features characteristics of compound pahoehoe lava flows. Similar ridges and mounds were identified in the Tharsis region of Mars.

  15. Las comunidades vegetales del Zacatonal Alpino de los volcanes Popocatépetl y Nevado de Toluca, Región Central de México.

    NARCIS (Netherlands)

    Almeida-Lenero, L.; Gimenez de Azcarate, J.; Cleef, A.M.; Gonzales Trapaga, A.

    2004-01-01

    This study of the zacatonal alpino zone of the volcanoes Popocatepetl (5452 in) and Nevado de Toluca (4690 m) in the central region of the Transmexican Volcanic Belt, is a follow-up of the study of ALMEIDA et al. (1994). This tropical alpine zacatonal represents the potential vegetation of the altit

  16. Early Cretaceous arc volcanic suite in Cebu Island, Central Philippines and its implications on paleo-Pacific plate subduction: Constraints from geochemistry, zircon U-Pb geochronology and Lu-Hf isotopes

    Science.gov (United States)

    Deng, Jianghong; Yang, Xiaoyong; Zhang, Zhao-Feng; Santosh, M.

    2015-08-01

    The Philippine island arc system is a collage of amalgamated terranes of oceanic, continental and island arc affinities. Here we investigate a volcanic suite in Cebu Island of central Philippines, including basalt, diabase dike, basaltic pyroclastic rock and porphyritic andesite. LA-ICP-MS U-Pb geochronology of zircon grains from the porphyritic andesite and pyroclastic rock yielded ages of 126 ± 3 Ma and 119 ± 2 Ma, respectively, indicating an Early Cretaceous age. The age distribution of the detrital zircons from river sand in the area displays a peak at ca. 118 Ma, close to the age of the pyroclastic rock. The early Cretaceous volcanic rocks in the central Philippines were previously regarded as parts of ophiolite complexes by most investigators, whereas the Cebu volcanics are distinct from these, and display calc-alkaline affinity and island arc setting, characterized by high LREE/HREE ratios and low HFSE contents. These features are similar to the Early Cretaceous arc basalts in the Amami Plateau and east Halmahera in the northernmost and southernmost West Philippine Basin respectively. Zircon Hf isotopes of the pyroclastic rocks show depleted nature similar to those of the Amami Plateau basalts, implying the subducted Pacific-type MORB as probable source. Zircon Hf isotopes of the porphyritic andesite show slight enrichment relative to that of the pyroclastic rocks and MORB, indicating subducted sediments as a minor end-member in the source. The Hf isotopic compositions of the volcanic rocks are also reflected in the detrital zircons from the river sands. We propose that the volcanic rocks of Cebu Island were derived from partial melting of sub-arc mantle wedge which was metasomatized by dehydration of subducted oceanic crust together with minor pelagic sediments. Within the tectonic environment of Southeast Asia during Early Cretaceous, the volcanic rocks in Cebu Island can be correlated to the subduction of paleo-Pacific plate. The Early Cretaceous

  17. Paleoproterozoic felsic volcanism of Iricoumé group, Erepecuru-Trombetas domain, Amazonian central province: Field and petrographic characterization and Pb-Pb zircon geochronology

    Directory of Open Access Journals (Sweden)

    Lúcia Travassos da Rosa Costa

    2013-03-01

    Full Text Available The Iricoumé group consists of very well preserved pyroclastic and effusive volcanic rocks as a part of an extensive volcano-plutonic event, which marked the central part of the Amazonian craton during the Orosirian. Such rocks occur in the southern part of the southwestern of Erepecuru-Trombetas Domain (NW of the Pará state, south of the Guyana Shield. Petrographic study allows distinction of two volcanic types. A dominant explosive volcanism is characterized by pyroclastic rocks (ignimbrites, rheoignimbrites, lapilli-tuff related to surge deposit, and co-ignimbrite fall tuff while a subordinated effusive volcanism is represented by coherent lavas flows and hypabissal rocks (andesites, lamprophyres and latites. Most of the pyroclastic rocks exhibit features of deposition under high temperature suggesting formation in a caldera-related environment. Pb-Pb zircon ages of 1888 +-2.5 and 1889 +-2 Ma have been obtained for the formation of trachydacitic ignimbrites and confirm that the dominant volcanism is part of the Iricoumé group. The Pb-Pb zircon age of 1992 +-3 Ma yielded by an andesite points to the occurrence in the area of an older Orosirian magmatic episode, which has been previously recognized locally southward in the Tapajós domain. These new results constitute a further evidence of the wide extent of the Iricoum group and correlated volcanic rocks in the central part of the Amazonian craton, and reinforce the assumption that this volcanic episode and correlated magmatism may be considered as a silicic large igneous province (SLIP, as previously proposed by some authors.

  18. Central nervous system tuberculosis: MRI

    International Nuclear Information System (INIS)

    The MRI findings of 18 proven cases of central nervous system (CNS) tuberculosis were reviewed; 10 patients were seropositive for HIV. All had medical, laboratory, or surgical proof of CNS tuberculosis. Eleven patients had meningitis, of whom two also had arachnoiditis. Five patients had focal intra-axial tuberculomas: four brain masses and one an intramedullary spinal lesion. Two patients had focal extra-axial tuberculomas: one in the pontine cistern, and one in the spine. In all 11 patients with meningitis MRI showed diffuse, thick, meningeal enhancement. All intraparenchymal tuberculomas showed low signal intensity on T2-weighted images and ring or nodular enhancement. The extra-axial tuberculomas had areas isointense or hypointense relative to normal brain and spinal cord on T2-weighted images. Although tuberculous meningitis cannot be differentiated from other meningitides on the basis of MR findings, intraparenchymal tuberculomas show characteristic T2 shortening, not found in most other space-occupying lesions. In the appropriate clinical setting, tuberculoma should be considered. (orig.)

  19. Monitoring volcanic systems through cross-correlation of coincident A-Train satellite data.

    Science.gov (United States)

    Flower, V. J. B.; Carn, S. A.; Wright, R.

    2014-12-01

    The remote location and inaccessibility of many active volcanic systems around the world hinders detailed investigation of their eruptive dynamics. One methodology for monitoring such locations is through the utilisation of multiple satellite datasets to elucidate underlying eruption dynamics and aid volcanic hazard mitigation. Whilst satellite datasets are often analysed individually, here we exploit the multi-platform NASA A-Train satellite constellation, including the Ozone Monitoring Instrument (OMI) on Aura and Moderate Resolution Imaging Spectroradiometer (MODIS) on Aqua. OMI measures volcanic emissions (e.g. sulphur dioxide, ash) whilst MODIS enables monitoring of thermal anomalies (e.g. lava flows, lava lakes, pyroclastic deposits), allowing analysis of a more diverse range of volcanic unrest than is possible using a single measurement technique alone, and permitting cross-correlation between datasets for specific locations to assess cyclic activity. A Multi-taper (MTM) Fast Fourier Transform (FFT) analysis was implemented at an initial sample site (Soufriere Hills volcano [SHV], Montserrat) facilitating cycle identification and subsequent comparison with existing ground-based data. Corresponding cycles at intervals of 8, 12 and ~50 days were identified in both the satellite-based SO2 and thermal infrared signals and ground-based SO2 measurements (Nicholson et al. 2013), validating the methodology. Our analysis confirms the potential for identification of cyclical volcanic activity through synergistic analysis of satellite data, which would be of particular value at poorly monitored volcanic systems. Following our initial test at SHV, further sample sites have been selected in locations with varied eruption dynamics and monitoring capabilities including Ambrym (Vanuatu), Kilauea (Hawaii), Nyiragongo (DR Congo) and Etna (Italy) with the intention of identifying not only cyclic signals that can be attributed to volcanic systems but also those which are

  20. Identifying the volcanic eruption depicted in a neolithic painting at Çatalhöyük, Central Anatolia, Turkey.

    Science.gov (United States)

    Schmitt, Axel K; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M

    2014-01-01

    A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with (14)C ages for cultural strata at Çatalhöyük, including level VII containing the "map" mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard. PMID:24416270

  1. Linking hydropedology and ecosystem services: differential controls of surface field saturated hydraulic conductivity in a volcanic setting in central Mexico

    Directory of Open Access Journals (Sweden)

    A. Gómez-Tagle

    2009-03-01

    Full Text Available In this study the variation of field saturated soil hydraulic conductivity (Kfs as key control variable and descriptor of infiltration was examined by means of a constant head single ring infiltrometer. The study took place in five coverage types and land uses in a volcanic setting in central Mexico. The tested hypothesis was that there exist a positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible controls of Kfs, for this volcanic setting. Land use history driven erosion plays a decisive role in subsurface horizon presence at the surface and soil matrix characteristic determination, while plant succession patterns seem to be strongly linked to soil bioturbation and

  2. Depositional conditions of the coal-bearing Hirka Formation beneath Late Miocene explosive volcanic products in NW central Anatolia, Turkey

    Indian Academy of Sciences (India)

    Mehmet Şener

    2007-04-01

    This work focuses on the relationship between the coal deposition and explosive volcanism of the Miocene basin, NW central Anatolia, Turkey. The coal-bearing Hirka Formation was deposited over the Galatian Andesitic Complex and/or massive lagoonal environments during the Miocene. The investigated lignite is a high ash (from 32 to 58%) and sulphur (from 1.43 to 3.03%) lignite which is petrographically characterised by a high humunite content. The mineral matter of the studied lignite samples is made up of mainly clay minerals (illite–smectite and kaolinite), plagioclase and quartz in Bolu coal field, clay minerals (illite–smectite, smectite and illite), quartz, calcite, plagioclase and gypsum in Seben coal field, quartz, K-feldspar, plagioclase and clay minerals (kaolinite and illite) in Kıbrıscık, and dolomite, quartz, clinoptilolite, opal CT and gypsum in C¸ amlıdere coal field. The differences in these four types of lignite with specific mineralogical patterns may be due to the explosive volcanic events and depositional conditions which changed from one coal field to the others. There is a zonation from SW to SE in the studied area for zeolites such as Opal CT+smectite-clinoptilolite-analcime-K-feldspar. Carbonate minerals are commonly calcite in Seben and Kıbrıscık coal fields. In Bolu, coal samples are devoid of calcite and dolomite. These analyses show that there is an increase in the amount of Mg and a decrease in the amount of Na from the northwestern part to the southern part in the study area.

  3. Subduction, volcanism, collision, orogenesis and faults: How do they shape the central Mediterranean region?

    OpenAIRE

    Baccheschi, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D’Amico, S.; University of Malta

    2014-01-01

    From a geological and geodynamical point of view, the central Mediterranean area represents one of the most intriguing and enigmatic regions in the world and it still continues to capture Earth scientists’ attention. The region is characterized by spectacular surface geological features due to the complex mechanisms in the lithosphere and mantle of this fascinating region. Long-term geodynamical processes as well as active tectonics are testified by high mountain belts (up to 4000 m) thous...

  4. About the use of radon in the surveillance of volcanoes from Central America; De l`utilisation du radon dans la surveillance des volcans d`amerique centrale

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, E. [Obviscori, Heridia (Costa Rica); Garcia Vindas, R.; Monnin, M.; Seidel, J.L. [Centre National de la Recherche Scientifique (CNRS), 34 -Montpellier (France). Centre d`Etudes Phytosociologiques et Ecologiques Louis-Emberger; Segovia, N. [ININ, Mexico (Mexico)

    1996-12-31

    Anomalous fluctuations of radon content in soil gases, fumaroles or thermal sources associated with volcanic systems are considered as precursors of deep degassing phenomena. Radon measurements in soil gases were performed for several years on three active volcanoes of Costa-Rica (Arenal, Irazu, Poas), also on El Chichon and Colima volcanoes in Mexico and more recently on the Popocatepetl since its reactivation in December 1994. Data acquisition was initially performed using plastic detectors with a 15 days integration. Since 1993, autonomous automatic probes are used and give hourly measurements. A nine stations network for ground measurements is installed on the Poas since 1982. Radon and Cl{sup -}, F{sup -} and SO{sub 4}{sup 2-} variations of the main crater lake are examined and correlated with the volcanic activity which led to the decay and disappearing of the lake in April 1989. On the Irazu, five stations were installed in 1982 and 3 automatic ones were added in November 1993. Results obtained so far are discussed according to the phreatic eruption of December 1994. The Popocatepetl measurements obtained since December 1994 are presented too. Abstract only. (J.S.).

  5. Pattern of geochemical variations within the volcanic system of Mt Etna, Italy, from 1995 to 2013

    Science.gov (United States)

    Corsaro, Rosa Anna; Falsaperla, Susanna; Langer, Horst

    2016-04-01

    Dynamic and evolution of magma in the plumbing system are key aspects in the evaluation of volcanic hazard. Eruptive phenomena involve indeed processes of magma upraise and storage, which may change in time and space, and mirror in the composition of volcanic products. In this study, we analyze the pattern of geochemical variations at Etna, Italy, from 1995 to 2013. In this time span, volcanic activity affected all the four craters close to the summit of the volcano (located at about 3300 m above the sea level), and fed eruptive fissures along its upper flanks. In addition, a new crater formed and rapidly built up, giving rise to spectacular lava fountains from 2011 on. Based on a dataset containing the geochemical composition of volcanic products collected over 18 years, we explored the application of data mining methods in the framework of the European MEDiterrranean Supersite Volcanoes (MED­-SUV) project. In the present application, we discuss the relationships among the composition of volcanic products sampled from all the afore-mentioned eruptive centers. Our results highlight differences in magma evolution, dynamic and eruptive style even within a single eruptive center.

  6. Geochemical signatures of the diffuse CO2 emission from Brava volcanic system, Cape Verde

    Science.gov (United States)

    Rodriguez, F.; Bandomo, Z.; Barros, I.; Dias Fonseca, J.; Fernandes, P.; Rodrigues, J.; Melian Rodriguez, G.; Padron, E.; Dionis, S.; Sonia, S.; Gonçalves, A.; Fernandes, A.; Hernandez Perez, P. A.; Perez, N.

    2010-12-01

    Brava (67 km2) the smallest of the populated Cape Verde islands, lies at the southwestern end of the archipelagic crescent. Brava volcanic system has no documented historical eruptions, but its youthful volcanic morphology and the fact that earthquake swarms still occur indicate the potential for future eruptions. A geochemical survey of diffuse gas emissions was carried out in Brava island during February and March 2010. For this survey 228 sampling sites were selected all over the island to perform soil CO2 efflux measurements, using a portable accumulation chamber and an IR sensor, and soil temperature measurements at a depth of 30-50 cm. Soil gas samples were collected at 40 cm depth for chemical (He, H2, N2, CO2, CH4, Ar and O2) and isotopic (δ13C-CO2) analysis in 32 selected sampling sites. CO2 efflux values ranged from non-detectable up to 1.343 g m-2 d-1. To quantify the total diffuse CO2 emission from Brava volcanic system, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (˜2 g m-2 d-1), while peak levels (>1300 g m-2 d-1) were mainly identified at Vinagre and Baleia areas. The total diffuse CO2 output from Brava volcanic system was estimated about 41.6 t d-1. The analysis of the carbon isotopic signature of the CO2 in the soil atmosphere provides an insight for evaluating the origin of the diffuse CO2 emission. Observed δ13C-CO2 values ranged from -20.86 to -1.26 ‰. A binary plot of CO2 concentrations versus δ13C-CO2 values allows us to represent three major geochemical reservoirs (atmospheric air, volcanic gas, and biogenic gas) and their related mixing lines. The chemical and isotopic analysis of Brava soil gas samples suggest a mixing with deep-seated CO2 and biogenic gas for the diffuse CO2 emission from Brava volcanic system. The lack of visible volcanic gas emission in Brava highlights the importance of monitoring diffuse CO2 emission to improve its

  7. Melt extraction in mush zones: The case of crystal-rich enclaves at the Sabatini Volcanic District (central Italy)

    Science.gov (United States)

    Masotta, M.; Mollo, S.; Gaeta, M.; Freda, C.

    2016-04-01

    A peculiar feature of the Sabatini Volcanic District (SVD, central Italy) is the occurrence of crystal-poor pumices and crystal-rich enclaves within the same eruptive host-deposit. The stratigraphic sequence of pumices and enclaves indicates the tapping of a stratified magma chamber, where a crystal-poor phonolitic magma lay on top of a more primitive crystal-rich magma. The crystal-rich enclaves are genetically related to the pumices and record the evolution of a solidification front, in which a more differentiated melt was produced, extracted and eventually erupted. We collected and analyzed crystal-rich enclaves from one of the largest phonolitic eruptions at the SVD and used their petrological and geochemical features to reconstruct magma differentiation and crystal-melt separation in the solidification front. On this basis, three groups of enclaves have been identified: porphyritic enclaves, holocrystalline enclaves and sanidinites. The mineralogical variability faithfully reproduces the spatial and temporal evolution expected of a solidification front, from early-to-intermediate crystallization conditions (porphyritic and holocrystalline type) to the late stage of solidification (sanidinites), in which the percolation of a more differentiated melt through the crystal mush triggered the instability of the solidification front. Results from numerical models indicate that gravitational instability is the most efficient mechanism to explain melt extraction in mush zones of medium-sized (~ 10 km3), short-lived (~ 104 years) magma chambers.

  8. The influence of volcanic activity in the Campi Flegrei coastal depositional system

    Science.gov (United States)

    Violante, Crescenzo; Esposito, Eliana; Molisso, Flavia; Porfido, Sabina; Sacchi, Marco

    2010-05-01

    The Campi Flegrei coastal area includes the bay of Pozzuoli, Procida and Ischia islands, characterized by active tectonics and volcanism since the Pleistocene. Numerous monogenic volcanoes occur close to the shoreline and volcanic debris interpreted as submarine counterpart of subaerial flows and surges, have been detected offshore. In the Pozzuoli area the most recent eruptive volcanic activity occurred from 10.0 to 8.0 ky B.P and 4.5 to 3.7 ky B.P. followed by the September 1538 Monte Nuovo eruption. Here magma-related activity is testified by extensive hydrothermalism, and recent episodes (1970-71 and 1982-84 on Pozzuoli coast) of shallow seismicity and ground deformation, exceeding rates of 100 cm/year in the years 1983-1984. The most recent volcanic activity on Ischia island starts around 10.0 ky B.P. to which associates several eruptive centres mostly located in the western sector. The last eruption dates back to Arso flow in 1302. Nevertheless the landscape of Ischia is dominated by Mount Epomeo in the central part of the island, which is the highest peak (788 m). It is a volcano-tectonic structure that raised above sea level between 33 and 28 ka BP, due to the intrusion of magma at shallow depth. Procida island is composed of five monogenic Volcanoes (Vivara, Terra Murata, Pozzo Vecchio, Fiumicello and Solchiaro) that have been active over the last 80 ky producing pyroclastic deposits and a lava dome. A sixth volcanic structure has been reported recently off P.ta Serra by marine investigations and confirmed by airborne magnetic surveys. The emplacement of large amount of volcanoclastic material from volcanic and volcano-tectonic activity in the Campi Flegrei coastal area produced extensive avalanche deposits off Ischia island, seafloor instabilities in the form of creep/slump, channelled sediment flow and deep sedimentary fans, and is largely responsible for aggradation/progradation of the coastal area during the Quaternary. Moreover, numerous volcanic bank

  9. Directed Volcanic Blast as a Tragedy of October 26Th, 2010 at Merapi Volcano, Central Java

    Directory of Open Access Journals (Sweden)

    Igan S. Sutawidjaja

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i3.163Merapi is an active strato volcano located in Central Java. This volcano is regarded as the most active and most dangerous volcano in Indonesia. Since the twentieth century, the activities have comprised mainly the effusive growth of viscous lava domes and lava tongues, with occasional gravitational collapses of parts of over-steepened domes producing pyroclastic flows, commonly defined as “Merapi-Type”. Since October 2010, however, explosive eruptions of a relatively large size have occurred to VEI 4, and some associated pyroclastic flows were larger and had farther reach than any produced on July 2006. These events may also be regarded as another type of eruptions for Merapi. On October26th, 2010 such event happened, even though it was not caused by pyroclastic flows of the dome collapses, about thirty people were killed including Mbah Marijan, known as the Merapi volcano's spiritual gatekeeper, who was found dead at his home approximately 4 km from the crater. The Yogyakarta Palace subsequently confirmed his death. This time the disaster was caused by a sudden directed blast that took place at 17:02 pm throughout Cangkringan, Kinahrejo Village, at the south flank of Merapi Volcano. The victims were the local people who did not predict the blast threatened their areas, because they believed that the pyroclastic flows from the dome collapses as long as they knew, did not threaten their areas, and pyroclastic flows would flow down following the Boyong River as the closest valley to their village. The blast swept an area about 8 km2, reaching about 5 km in distance, deposited thin ash, and toppled all trees to the south around the Kinahrejo and Pakem areas. The blast that reached Kinahrejo Village seemed to have moderate temperatures, because all trees facing the crater were not burnt. However, the victims were affected by dehydration and blanketed by fine ash.

  10. Chemistry of surface water at a volcanic summit area, Norikura, central Japan: multivariate statistical approach.

    Science.gov (United States)

    Anazaw, K; Ohmori, L H

    2001-11-01

    Many hydrochemical studies on chemical formation of shallow ground water have been reported as results of water-rock interaction, and contamination of paleo-brine or human activities, whereas the preliminary formation of precipitation source in the recharged region has not been established yet. The purpose of this research work is to clarify the geochemical process of water formation from a water source unpolluted by seawater or human activity. Norikura volcano, located in western part of central Japan provided a suitable source for this research purpose, and hence chemical compositions of water samples from the summit and the mountainside area of Norikura volcano were determined. Most samples in the summit area showed very low electrical conductivity, and lower than 12 microS/cm. On the basis of the chemical compositions, principal component analysis (PCA) and factor analysis (FA), such as kinds of multivariate statistical techniques were used to extract geochemical factors affecting hydrochemical process. As a result, three factors were extracted. The first factor showed high loading on K+, Ca2+, SO2 and SiO2, and this factor was interpreted due to influence of the chemical interaction between acidic precipitated water and rocks. The second factor showed high loading on Na+ and Cl-, and it was assumed to be an influence of seawater salt. The third factor showed loading on NO3-, and it was interpreted to be caused by biochemical effect of vegetation. The proportionate contributions of these factors to the evolution of water chemical composition were found to be 45%, 20%, and 10% for factors 1, 2 and 3, respectively. The same exploration at the mountainside of Norikura volcano revealed that the chemical variances of the non-geothermal water samples were highly influenced by water-rock interactions. The silicate dissolution showed 45% contribution for all chemical variances, while the adsorption of Ca2+ and Mg2+ by precipitation or ion exchange showed 20

  11. Estimation of the geothermal potential of the Caldara di Manziana sitein the Sabatini Volcanic District (central Italy) by integratinggeochemical data and 3D-GIS modelling

    OpenAIRE

    Ranaldi, M.; Università Roma Tre; Lelli, M.; CNR-IGG; Tarchini, L.; Università Roma Tre; Carapezza, M. L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Patera, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia

    2016-01-01

    This study evaluated the geothermal potential of Caldara di Manziana in central Italy. The chemical com-position of gas emissions was used for geothermometric-geobarometric estimations and the total amountof CO2released was assessed. The subsurface geology was reconstructed using data from deep exploratoryand shallow temperature-gradient wells. The bottom of the superficial volcanic deposits, the thickness ofthe impervious flysch cover and the top of the geothermal reservoir hosted in fractur...

  12. New Evidence of Holocene Mass Wasting Events in Recent Volcanic Lakes from the French Massif Central (Lakes Pavin, Montcineyre and Chauvet) and Implications for Natural Hazards

    OpenAIRE

    Chapron, Emmanuel; Ledoux, Grégoire; SIMONNEAU, Anaëlle; Albéric, Patrick; St-Onge, Guillaume; Lajeunesse, Patrick; Boivin, Pierre

    2011-01-01

    High-resolution seismic profiling (12 kHz) surveys combined with sediment cores, radiocarbon dating, tephrochronology and multibeam bathymetry (when available) allow documentation of a range of Holocene mass wasting events in nearby contrasting lakes of volcanic origin in the French Massif Central (45°N, 2°E): two deep maar lakes (Pavin and Chauvet) and a shallow lake (Montcineyre) dammed by the growth of a volcano. In these lacustrine environments dominated by authigenic sedimentation, recen...

  13. [Functional anatomy of the central nervous system].

    Science.gov (United States)

    Krainik, A; Feydy, A; Colombani, J M; Hélias, A; Menu, Y

    2003-03-01

    The central nervous system (CNS) has a particular regional functional anatomy. The morphological support of cognitive functions can now be depicted using functional imaging. Lesions of the central nervous system may be responsible of specific symptoms based on their location. Current neuroimaging techniques are able to show and locate precisely macroscopic lesions. Therefore, the knowledge of functional anatomy of the central nervous system is useful to link clinical disorders to symptomatic lesions. Using radio-clinical cases, we present the functional neuro-anatomy related to common cognitive impairments.

  14. Ecological characteristics and management of geothermal systems of the Taupo Volcanic Zone, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Boothroyd, Ian K.G. [Golder Associates Ltd., P.O. Box 33849, Takapuna, and School of Geography, Geology and Environmental Science, University of Auckland, Private Bag 92019, Auckland (New Zealand)

    2009-03-15

    New Zealand has an array of geothermal systems with distinctive ecological features, with many occurring in the Taupo Volcanic Zone in the Central North Island. Associated with these geothermal features are characteristic geophysical and geochemical components, and distinctive terrestrial and aquatic ecosystems with many attributes that are common across a range of the biotic groups. Zonation amongst vegetation communities is closely related to soil temperature and these associations generally occur in a predictable sequence along the soil temperature gradient. Similarly, clear distinctions in aquatic flora and fauna occur longitudinally downstream from the source of thermal springs and vertically on geyser mounds. The characteristic vegetation communities associated with geothermal fields and the invertebrate and algal communities found in geothermally influenced springs and streams are described, in particular the features of the Wairakei geothermal field. At this field four plant associations are recognized (non-vegetated soilfield, prostrate kanuka shrubland, prostrate kanuka scrub, mixed fernland), but all the major aquatic macroinvertebrate groups are represented and commonly found in natural freshwaters throughout New Zealand. The current management of geothermal ecosystems is reviewed with particular reference to the Waikato region of New Zealand. Management of geothermal resources in New Zealand aims to balance development with the protection of highly valued surface features via a series of regional policies, rules and regulations. Geothermal habitats, ecological gradients, and at-risk geothermal plants are included in the definition of geothermal systems for management purposes. With the recognition of the unique ecological diversity and function of geothermal ecosystems, knowledge and understanding of their ecological characteristics will be critical to the ability to utilize and sustain geothermal resources into the future. (author)

  15. Age and petrology of the Usun Apau and Linau Balui volcanics : windows to central Borneo’s interior.

    OpenAIRE

    Cullena, A.; Macpherson, C.; Taib, N. I.; Burton-Johnson, A.; Dennis Geist, D.; Spell, T.; Banda, R.M.

    2013-01-01

    The Usun Apau plateau lies in a remote area of Sarawak along the Tinjar Line, which defines the onshore part of a suture between the Luconia and Dangerous Grounds blocks. Reconnaissance studies in late 1950s established that the plateau is composed of a bimodal suite of young volcanic rocks, but no further work exists to constrain the age and petrogenesis of the Usun Apau volcanics. We present and discuss new data from a suite of volcanic rocks recently collected from the Usun Apau region. Th...

  16. Topaz magmatic crystallization in rhyolites of the Central Andes (Chivinar volcanic complex, NW Argentina): Constraints from texture, mineralogy and rock chemistry

    Science.gov (United States)

    Gioncada, Anna; Orlandi, Paolo; Vezzoli, Luigina; Omarini, Ricardo H.; Mazzuoli, Roberto; Lopez-Azarevich, Vanina; Sureda, Ricardo; Azarevich, Miguel; Acocella, Valerio; Ruch, Joel

    2014-01-01

    Topaz-bearing rhyolite lavas were erupted as domes and cryptodomes during the early history of the Late Miocene Chivinar volcano, in Central Andes. These are the only topaz rhyolite lavas recognized in Central Andes. Textural, mineralogical and geochemical data on the Chivinar rhyolites suggest that topaz crystallized from strongly residual, fluorine-rich, peraluminous silicate melts of topazite composition before the complete solidification of the lava domes. Crystallization of the rhyolitic magma began with sodic plagioclase and alkali feldspar phenocrysts in the magma chamber, followed by groundmass quartz + alkali feldspar + minor sodic plagioclase during dome emplacement, and terminated with quartz + topaz + vapour bubbles forming small scattered miaroles. Fluorine partitioning into the fluid phase occurred only in the final stage of groundmass crystallization. The magmatic origin of topaz indicates the presence of a fluorine-rich highly differentiated magma in the early history of the Chivinar volcano and suggests the possibility of rare metals mineralizations related to the cooling and solidification of a silicic magma chamber. A late fluid circulation phase, pre-dating the andesitic phase of the Chivinar volcano, affected part of the topaz rhyolite lavas. The presence of Nb, Ta and Mn minerals as primary accessories in the rhyolites and as secondary minerals in veins suggests a connection of the fluid circulation phase with the silicic magmatic system. Although at the edge of the active volcanic arc, the Chivinar topaz rhyolites are in correspondence of the transtensive Calama-Olacapato-El Toro fault system, suggesting preferred extensional conditions for the formation of magmatic topaz in convergent settings, consistently with evidence from other known cases worldwide.

  17. Database compilation for the geologic map of the San Francisco volcanic field, north-central Arizona

    Science.gov (United States)

    Bard, Joseph A.; Ramsey, David W.; Wolfe, Edward W.; Ulrich, George E.; Newhall, Christopher G.; Moore, Richard B.; Bailey, Norman G.; Holm, Richard F.

    2016-01-08

    The main component of this publication is a geologic map database prepared using geographic information system (GIS) applications. The geodatabase of geologic points, lines, and polygons was produced as a compilation from five adjoining map sections originally published as printed maps in 1987 (see references in metadata). Four of the sections (U.S. Geological Survey Miscellaneous Field Studies Maps MF–1957, MF–1958, MF–1959, MF–1960) were created by scanning and geo-referencing stable base map material consisting of mylar positives. The final section (MF–1956) was compiled by hand tracing an enlargement of the available printed paper base map onto mylar using a #00 rapidograph pen, the mylar positive was then digitally scanned and geo-referenced. This method was chosen because the original basemap materials (mylar positives) for the MF–1956 section were unavailable at the time of this publication. Due to the condition of the available MF–1956 map section used as the base (which had previously been folded) the accuracy within the boundary of the MF–1956 section is presumed to be degraded in certain areas. The locations of the degraded areas and the degree of degradation within these areas is unclear. Final compilation of the database was completed using the ArcScan toolset, and the Editor toolset in ESRI ArcMap 10.1. Polygon topology was created from the lines and labels were added to the resultant geological polygons, lines, and points. Joseph A. Bard and David W. Ramsey updated and corrected the geodatabase, created the metadata and web presence, and provided the GIS-expertise to bring the geodatabase and metadata to completion. Included are links to files to view or print the original map sheets and the accompanying pamphlets.

  18. Miniaturized Airborne Imaging Central Server System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation is a miniaturized airborne imaging central server system (MAICSS). MAICSS is designed as a high-performance computer-based electronic backend that...

  19. Miniaturized Airborne Imaging Central Server System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation is a miniaturized airborne imaging central server system (MAICSS). MAICSS is designed as a high-performance-computer-based electronic backend that...

  20. NCPC Central Files Information System (CFIS)

    Data.gov (United States)

    National Capital Planning Commission — This dataset contains records from NCPC's Central Files Information System (CFIS), which is a comprehensive database of projects submitted to NCPC for design review...

  1. Staging Childhood Central Nervous System Embryonal Tumors

    Science.gov (United States)

    ... children. See the PDQ summary on Adult Central Nervous System Tumors Treatment for more information on the treatment of adults. There are different types of CNS embryonal tumors. Enlarge Anatomy of the inside of the brain, showing the ...

  2. Focal lesions in the central nervous system

    International Nuclear Information System (INIS)

    This report reviews the animal and human studies currently in progress at LBL with heavy-ion beams to induce focal lesions in the central nervous system, and discusses the potential future prospects of fundamental and applied brain research with heavy-ion beams. Methods are being developed for producing discrete focal lesions in the central nervous system using the Bragg ionization peak to investigate nerve pathways and neuroendocrine responses, and for treating pathological disorders of the brain

  3. SIMULATION OF THE ICELAND VOLCANIC ERUPTION OF APRIL 2010 USING THE ENSEMBLE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.

    2011-05-10

    The Eyjafjallajokull volcanic eruption in Iceland in April 2010 disrupted transportation in Europe which ultimately affected travel plans for many on a global basis. The Volcanic Ash Advisory Centre (VAAC) is responsible for providing guidance to the aviation industry of the transport of volcanic ash clouds. There are nine such centers located globally, and the London branch (headed by the United Kingdom Meteorological Office, or UKMet) was responsible for modeling the Iceland volcano. The guidance provided by the VAAC created some controversy due to the burdensome travel restrictions and uncertainty involved in the prediction of ash transport. The Iceland volcanic eruption provides a useful exercise of the European ENSEMBLE program, coordinated by the Joint Research Centre (JRC) in Ispra, Italy. ENSEMBLE, a decision support system for emergency response, uses transport model results from a variety of countries in an effort to better understand the uncertainty involved with a given accident scenario. Model results in the form of airborne concentration and surface deposition are required from each member of the ensemble in a prescribed format that may then be uploaded to a website for manipulation. The Savannah River National Laboratory (SRNL) is the lone regular United States participant throughout the 10-year existence of ENSEMBLE. For the Iceland volcano, four separate source term estimates have been provided to ENSEMBLE participants. This paper focuses only on one of those source terms. The SRNL results in relation to other modeling agency results along with useful information obtained using an ensemble of transport results will be discussed.

  4. The origin of groundwater arsenic and fluorine in a volcanic sedimentary basin in central Mexico: a hydrochemistry hypothesis

    Science.gov (United States)

    Morales-Arredondo, Iván; Rodríguez, Ramiro; Armienta, Maria Aurora; Villanueva-Estrada, Ruth Esther

    2016-06-01

    A groundwater sampling campaign was carried out in the summer of 2013 in a low-temperature geothermal system located in Juventino Rosas (JR) municipality, Guanajuato State, Mexico. This groundwater presents high concentrations of As and F- and high Rn counts, mainly in wells with relatively higher temperature. The chemistry of major elements was interpreted with different methods, like Piper and D'Amore diagrams. These diagrams allowed for classification of four groundwater types located in three hydrogeological environments. The aquifers are hosted mainly in alluvial-lacustrine sediments and volcanic rocks in interaction with fault and fracture systems. The subsidence, faults and fractures observed in the study area can act as preferential channels for recharge and also for the transport of deep fluids to the surface, especially in the basin plain. The formation of a piezometric dome and the observed hydrochemical behavior of groundwater suggest a possible origin of the As and F-. Geochemical processes occurring during water-rock interaction are related to high concentrations of As and F-. High temperatures and alteration processes (like rock weathering) induce dissolution of As and F--bearing minerals, increasing the content of these elements in groundwater.

  5. Computerized Systems: Centralized or Decentralized?

    Science.gov (United States)

    Seitz, Linda Ludington

    1985-01-01

    Computerized management information systems have long been used in business, and data integration and sophisticated programing now enable many businesses to decentralize their information operations. This approach has advantages and disadvantages that colleges and universities must weigh and plan for carefully. (MSE)

  6. USGS Volcanic Activity Alert-Notification System Description

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Website provides plain-English description of the alert notification system that the USGS has adopted nationwide for characterizing the level of unrest and eruptive...

  7. Central histaminergic system and cognition.

    Science.gov (United States)

    Passani, M B; Bacciottini, L; Mannaioni, P F; Blandina, P

    2000-01-01

    The neurotransmitter histamine is contained within neurons clustered in the tuberomammillary nuclei of the hypothalamus. These cells give rise to widespread projections extending through the basal forebrain to the cerebral cortex, as well as to the thalamus and pontomesencephalic tegmentum. These morphological features suggest that the histaminergic system acts as a regulatory center for whole-brain activity. Indeed, this amine is involved in the regulation of numerous physiological functions and behaviors, including learning and memory, as indicated by extensive research reviewed in this paper. Histamine effects on cognition might be explained by the modulation of the cholinergic system. However, interactions of histamine with any transmitter system, and/or a putative intrinsic procognitive role cannot be excluded. Furthermore, although experimental evidence indicates that attention-deficit hyperactivity disorder symptoms arise from impaired dopaminergic and noradrenergic transmission, recent research suggests that histamine is also involved. The possible relevance of histamine in disorders such as age-related memory deficits, Alzheimer's disease and attention-deficit hyperactivity disorder is worth of consideration, and awaits validation with clinical trials that will prove the beneficial effects of histaminergic drugs in the treatment of these diseases.

  8. Petrogenesis of Volcanic Rocks in the Khabr-Marvast Tectonized Ophiolite: Evidence for Subduction Processes in the South-Western Margin of Central Iranian Microcontinent

    Institute of Scientific and Technical Information of China (English)

    Azam SOLTANMOHAMMADI; Mohammad RAHGOSHAY; Morteza KHALATBARI-JAFARI

    2009-01-01

    The Late Cretaceous Khabr-Marvast tectonized ophiolite is located in the middle part of the Nain-Baft ophiolite belt, at the south-western edge of the central Iranian microcontinent. Although all the volcanic rocks in the study area indicate subduction-related magmatism (e.g. high LILE (large ion lithophile elements)/ HFSE (high field strenght elements) ratios and negative anomalies in Nb and Ta), geological and geochemical data clearly distinguish two distinct groups of volcanic rocks in the tectonized association: (1) group 1 is comprised of hyaloclustic breccias, basaltic pillow iavas, and andesite sheet flows. These rocks represent the Nain-Baft oceanic crust; and (2) group 2 is alkaline iavas from the top section of the ophiolite suite. These lavas show shoshonite affinity, but do not support the propensity of ophiolite.

  9. Probabilities of future VEI ≥ 2 eruptions at the Central American Volcanic Arc: a statistical perspective based on the past centuries' eruption record

    Science.gov (United States)

    Dzierma, Yvonne; Wehrmann, Heidi

    2014-10-01

    A probabilistic eruption forecast is provided for seven historically active volcanoes along the Central American Volcanic Arc (CAVA), as a pivotal empirical contribution to multi-disciplinary volcanic hazards assessment. The eruption probabilities are determined with a Kaplan-Meier estimator of survival functions, and parametric time series models are applied to describe the historical eruption records. Aside from the volcanoes that are currently in a state of eruptive activity (Santa María, Fuego, and Arenal), the highest probabilities for eruptions of VEI ≥ 2 occur at Concepción and Cerro Negro in Nicaragua, which are likely to erupt to 70-85 % within the next 10 years. Poás and Irazú in Costa Rica show a medium to high eruption probability, followed by San Miguel (El Salvador), Rincón de la Vieja (Costa Rica), and Izalco (El Salvador; 24 % within the next 10 years).

  10. MRI of central nervous system anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Izawa, M.; Oikawa, A.; Matoba, A.

    1987-05-01

    MRI was very useful in the evaluation of congenital anomalies of central nervous system as well as other nervous system disease with three-dimensional spatial resolution. We had experienced MRI of central nervous system anomalies, demonstrated characterisitic findings in each anomaly. MRI is useful to observe the coronal, horizontal and sagittal images of the brain and spinal cord in order to discuss the etiological mechanisms of spinal dysraphysm and its associated anomalies. In case of spina bifida cystica MRI was available to decide operative indication for radical operation and tetherd cord developed from postoperative scar or accompanied intraspinal lesions.

  11. MRI of central nervous system anomalies

    International Nuclear Information System (INIS)

    MRI was very useful in the evaluation of congenital anomalies of central nervous system as well as other nervous system disease with three-dimensional spatial resolution. We had experienced MRI of central nervous system anomalies, demonstrated characterisitic findings in each anomaly. MRI is useful to observe the coronal, horizontal and sagittal images of the brain and spinal cord in order to discuss the etiological mechanisms of spinal dysraphysm and its associated anomalies. In case of spina bifida cystica MRI was available to decide operative indication for radical operation and tetherd cord developed from postoperative scar or accompanied intraspinal lesions. (author)

  12. Neotectonic development of the El Salvador Fault Zone and implications for deformation in the Central America Volcanic Arc: Insights from 4-D analog modeling experiments

    Science.gov (United States)

    Alonso-Henar, Jorge; Schreurs, Guido; Martinez-Díaz, José Jesús; Álvarez-Gómez, José Antonio; Villamor, Pilar

    2015-01-01

    The El Salvador Fault Zone (ESFZ) is an active, approximately 150 km long and 20 km wide, segmented, dextral strike-slip fault zone within the Central American Volcanic Arc striking N100°E. Although several studies have investigated the surface expression of the ESFZ, little is known about its structure at depth and its kinematic evolution. Structural field data and mapping suggest a phase of extension, at some stage during the evolution of the ESFZ. This phase would explain dip-slip movements on structures that are currently associated with the active, dominantly strike slip and that do not fit with the current tectonic regime. Field observations suggest trenchward migration of the arc. Such an extension and trenchward migration of the volcanic arc could be related to slab rollback of the Cocos plate beneath the Chortis Block during the Miocene/Pliocene. We carried out 4-D analog model experiments to test whether an early phase of extension is required to form the present-day fault pattern in the ESFZ. Our experiments suggest that a two-phase tectonic evolution best explains the ESFZ: an early pure extensional phase linked to a segmented volcanic arc is necessary to form the main structures. This extensional phase is followed by a strike-slip dominated regime, which results in intersegment areas with local transtension and segments with almost pure strike-slip motion. The results of our experiments combined with field data along the Central American Volcanic Arc indicate that the slab rollback intensity beneath the Chortis Block is greater in Nicaragua and decreases westward to Guatemala.

  13. Central nervous system complications after liver transplantation.

    Science.gov (United States)

    Kim, Jeong-Min; Jung, Keun-Hwa; Lee, Soon-Tae; Chu, Kon; Roh, Jae-Kyu

    2015-08-01

    We investigated the diversity of central nervous system complications after liver transplantation in terms of clinical manifestations and temporal course. Liver transplantation is a lifesaving option for end stage liver disease patients but post-transplantation neurologic complications can hamper recovery. Between 1 January 2001 and 31 December 2010, patients who had undergone liver transplantation at a single tertiary university hospital were included. We reviewed their medical records and brain imaging data and classified central nervous system complications into four categories including vascular, metabolic, infectious and neoplastic. The onset of central nervous system complications was grouped into five post-transplantation intervals including acute (within 1 month), early subacute (1-3 months), late subacute (3-12 months), chronic (1-3 years), and long-term (after 3 years). During follow-up, 65 of 791 patients (8.2%) experienced central nervous system complications, with 30 occurring within 1 month after transplantation. Vascular etiology was the most common (27 patients; 41.5%), followed by metabolic (23; 35.4%), infectious (nine patients; 13.8%), and neoplastic (six patients). Metabolic encephalopathy with altered consciousness was the most common etiology during the acute period, followed by vascular disorders. An initial focal neurologic deficit was detected in vascular and neoplastic complications, whereas metabolic and infectious etiologies presented with non-focal symptoms. Our study shows that the etiology of central nervous system complications after liver transplantation changes over time, and initial symptoms can help to predict etiology.

  14. Stochastic modelling of central heating systems

    DEFF Research Database (Denmark)

    Hansen, Lars Henrik

    1997-01-01

    and the degree Erhvervsforsker (a special Danish degree, equivalent to ``Industrial Ph.D.''). The thesis is mainly concerned with experimental design and system identification for individual components in water based central heating systems. The main contribution to this field is on the nonlinear dynamic...

  15. Interferons in the central nervous system

    DEFF Research Database (Denmark)

    Owens, Trevor; Khorooshi, Reza M. H.; Wlodarczyk, Agnieszka;

    2014-01-01

    Interferons (IFNs) are implicated as an important component of the innate immune system influencing viral infections, inflammation, and immune surveillance. We review here the complex biological activity of IFNs in the central nervous system (CNS) and associated glial–immune interactions...

  16. Cyanobacteria biennal dynamic in a volcanic mesotrophic lake in central Italy: Strategies to prevent dangerous human exposures to cyanotoxins.

    Science.gov (United States)

    Manganelli, Maura; Stefanelli, Mara; Vichi, Susanna; Andreani, Paolo; Nascetti, Giuseppe; Scialanca, Fabrizio; Scardala, Simona; Testai, Emanuela; Funari, Enzo

    2016-06-01

    Vico Lake, a volcanic meso-eutrophic lake in Central Italy, whose water is used for drinking and recreational activities, experienced the presence of the microcystins (MC) producing cyanobacterium Planktothrix rubescens. In order to assess the human health risks and to provide the local health authorities with a scientific basis for planning tailored monitoring activities, we studied P. rubescens ecology and toxicity for two years. P. rubescens generally dominated the phytoplankton community, alternating with Limnothrix redekei, potentially toxic. P. rubescens was distributed throughout the water column during winter; in summer it produced intense blooms where drinking water is collected (-20 m); here MC were detected all year round (0.5-5 μg/L), with implications for drinking water quality. In surface waters, MC posed no risk for recreational activities in summer, while in winter surface blooms and foams (containing up to 56 μg MC/L) can represent a risk for people and children practicing water sports and for animals consuming raw water. Total phosphorus, phosphate and inorganic nitrogen were not relevant to predict densities nor toxicity; however, a strong correlation between P. rubescens density and aminopeptidase ectoenzymatic activity, an enzyme involved in protein degradation, suggested a role of organic nitrogen for this species. The fraction of potentially toxic population, determined both as mcyB(+)/16SrDNA (10-100%) and as the MC/mcyB(+) cells (0.03-0.79 pg MC/cell), was much more variable than usually observed for P. rubescens. Differently from other Italian and European lakes, the correlation between cell density or the mcyB(+) cells and MC explained only ∼50 and 30% of MC variability, respectively: for Vico Lake, monitoring only cell or the mcyB(+) cell density is not sufficient to predict MC concentrations, and consequently to protect population health. Finally, during a winter bloom one site has been sampled weekly, showing that

  17. Tracking a closing volcanic system using repeating earthquakes

    Science.gov (United States)

    Buurman, H.; West, M. E.; Grapenthin, R.

    2011-12-01

    Repeating, volcano-tectonic (VT) earthquakes were recorded at the end of the explosive phase of the 2009 eruption of Redoubt Volcano, Alaska. The events cluster into several families which exhibit cross-correlation values greater than 0.8 and are distributed between 0-10 km below the edifice. The earthquake magnitudes decline gradually with time, and the events also appear to shallow as the sequence progresses. This activity continued for over 2 months and accompanied steady dome growth, which halted around the same time that the last of the repeating VTs were recorded. The repetitive nature of these earthquakes, their relatively deep locations and their occurrence following 3 weeks of major explosive eruptions suggest that they are related to changes around the conduit system and/or the magma storage area as the last of the magma was removed from the mid-crustal storage area. Geodetic data indicate that the deflation of the edifice, which had been continuous throughout the explosive activity, ceased coincident with the onset of the repeating VT earthquakes. We use evidence from earthquake relocations and earthquake focal mechanisms to investigate the source for the repeating VT earthquakes. We propose a model in which the repeating earthquakes are closely related to the adjustment of the conduit system and mid crustal storage area in response to the last of the ascending magma.

  18. Shallow structure of the Chichinautzin Range, southern Mexico basin, central Trans-Mexican Volcanic Belt. A gravity and seismic study

    Science.gov (United States)

    Campos-Enriquez, J. O.; Lermo-Samaniego, J. F.; Antahyua-Vera, Y. T.; Chavacan, M.; Ramón, V. M.; Hernández-García; Pita, C.

    2013-12-01

    Chichinautzin Range (ChR) closes to the S the Mexico Basin (MB). Initially based on height differences between MB and the to-he S-located Morelos Plataform (MP) , a major S-dipping fault was proposed. Depths differences to the limestone basement beneath MB and MP respectively supported its existence. This assumed fault was named La Pera. Earlier studies reported the existence of several faults affecting the ChR. New studies were focused to analyze the cinematic and dynamic character of faults to the W of ChR (Tenango Fault System) and of southern Sierra de la Cruces Range. Also based on a gravity study (Campos-Enríquez et al., 2000), the existence of a major N-dipping fault was inferred to delimit the MB to the S (i.e., delimiting the ChR to the N). Our study is based on gravity modelling, and local seismicity analysis. Accordingly, Mezosoic sandstones above metamorphic rocks constitute the basement underlying ChR. This structural high is faulted to the N and S. To the N, fault blocks displace the basement to larger depths (2-4 km). To the S the basement is shallower. The faults of the gravity model correlate with all reported faults, which collectively are refferred to as Aztlan Fault System. Two N-S MT profiles confirm the model. Several of these faults are associated with seismic activity with a N-S extension and a left-lateral component. The seismic event were located at depths of 7-15 km (i.e. the brittle crust). The system can be traced from the Nevado de Tolca volcano up to the Popocatépetl volcano and even further eastwards. The system is about 200 km long, 30-40 km wide, tectonically active. It enabled the fast emplacement of the ChR volcanic rocs. A flower-type structure was inferred to the S of ChR, further south, the profile is cut by faults belonging either to the Taxco-San Miguel de Allende Fault System or to the Chapala-Oaxaca Fault System. This profile shows how the transpressive tectonics, to the S, accomodates, with the N-S extension affecting

  19. Central functions of the orexinergic system

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yang Zhang; Lei Yu; Qian-Xing Zhuang; Jing-Ning Zhu; Jian-Jun Wang

    2013-01-01

    The neuropeptide orexin is synthesized by neurons exclusively located in the hypothalamus.However,these neurons send axons over virtually the entire brain and spinal cord and therefore constitute a unique central orexinergic system.It is well known that central orexin plays a crucial role in the regulation of various basic non-somatic and somatic physiological functions,including feeding,energy homeostasis,the sleep/wake cycle,reward,addiction,and neuroendocrine,as well as motor control.Moreover,the absence of orexin results in narcolepsy-cataplexy,a simultaneous somatic and non-somatic dysfunction.In this review,we summarize these central functions of the orexinergic system and associated diseases,and suggest that this system may hold a key position in somatic-non-somatic integration.

  20. Hydrogels for central nervous system therapeutic strategies.

    Science.gov (United States)

    Russo, Teresa; Tunesi, Marta; Giordano, Carmen; Gloria, Antonio; Ambrosio, Luigi

    2015-12-01

    The central nervous system shows a limited regenerative capacity, and injuries or diseases, such as those in the spinal, brain and retina, are a great problem since current therapies seem to be unable to achieve good results in terms of significant functional recovery. Different promising therapies have been suggested, the aim being to restore at least some of the lost functions. The current review deals with the use of hydrogels in developing advanced devices for central nervous system therapeutic strategies. Several approaches, involving cell-based therapy, delivery of bioactive molecules and nanoparticle-based drug delivery, will be first reviewed. Finally, some examples of injectable hydrogels for the delivery of bioactive molecules in central nervous system will be reported, and the key features as well as the basic principles in designing multifunctional devices will be described.

  1. Correlating the end-Triassic mass extinction and basalt volcanism of the Central Atlantic Magmatic Province at the 100,000-year level by high-precision U-Pb age determinations

    Science.gov (United States)

    Schoene, Blair; Guex, Jean; Bartolini, Annachiara; Schaltegger, Urs; Blackburn, Terrence J.

    2010-05-01

    The end-Triassic mass extinction is one of the five largest extinctions in Earth history, though considerable uncertainty remains in terms of its duration, causes and effects. Many workers suggest that the extinction was related directly or indirectly to adverse climate following the onset of the Central Atlantic Magmatic Province (CAMP), which erupted > 2.5x106 km3 of basalt in less than 1 Ma. However, there remains a need for precise and accurate geochronology to correlate the onset of CAMP volcanism, recorded uniquely in terrestrial sections, with the well-documented marine extinction event. We provide new chemical abrasion ID-TIMS U-Pb age determinations on ash bed and basaltic zircons using the well-calibrated EARTHTIME 202Pb-205Pb-233U-235U tracer solution, yielding data that are up to 70% more precise compared to single-Pb/single-U tracers. We show that the Triassic-Jurassic boundary (TJB) and end-Triassic biological crisis from two independent marine stratigraphic sections in northern Peru and in Nevada (USA) correlate with the onset of terrestrial flood volcanism in the Central Atlantic Magmatic Province (CAMP) to <150 ka. Ash bed samples reveal complicated U-Pb systematics, showing ranges in 206Pb/238U zircon dates of up to 2 Ma, representing a range of growth histories prior to eruption. Therefore, we use the youngest single closed-system zircon to approximate the eruption date. Three volcanic ash beds from the Pucara basin, northern Peru, bracket the TJB to a 206Pb/238U age of 201.31 ± 0.18/0.31/0.43 Ma (internal uncertainties/ with tracer calibration uncertainty/ with decay constant uncertainties). The first discovered ash bed from the New York canyon, Nevada, 1.5 m above TJB requires a boundary age of less than 201.33 ± 0.13 Ma. We also provide data from two laboratories which yield a new 206Pb/238U zircon age of 201.28 ± 0.02/0.22/0.31 Ma for the North Mtn. basalt, the lowest CAMP basalt from the Fundy basin, Nova Scotia. This narrows the

  2. Shallow sub-surface structure of the central volcanic complex of Tenerife, Canary Islands: implications for the evolution and the recent reactivation of the Las Canadas caldera

    Energy Technology Data Exchange (ETDEWEB)

    Gottsmann, J [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ (United Kingdom); Camacho, A G; Fernandez, J [Instituto de Astronomia y Geodesia (CSIC-UCM), Ciudad Universitaria, Pza. de Ciencias, 3, 28040 Madrid (Spain); MartI, J [Institute of Earth Sciences ' Jaume Almera' , CSIC, Lluis Sole SabarIs s/n, Barcelona 08028 (Spain); Wooller, L; Rymer, H [Department of Earth and Environmental Sciences, Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); GarcIa, A [Department of Volcanology, Museo Nacional de Ciencias Naturales, CSIC, C/ Jose Gutierrez Abascal, 2, 28006 Madrid (Spain)], E-mail: j.gottsmann@bristol.ac.uk

    2008-10-01

    We present a new local Bouguer anomaly map of the Central Volcanic Complex (CVC) of Tenerife, Spain. The high-density core of the CVC and the pronounced gravity low centred in the Las Canadas caldera (LCC) in greater detail than previously available. Mathematical construction of a subsurface model from the local anomaly data, employing a 3-D inversion enables mapping of the shallow structure beneath the complex, giving unprecedented insights into the sub-surface architecture of the complex, and shedding light on its evolution.

  3. The calc-alkaline and adakitic volcanism of the Sabzevar structural zone (NE Iran): Implications for the Eocene magmatic flare-up in Central Iran

    Science.gov (United States)

    Moghadam, Hadi Shafaii; Rossetti, Federico; Lucci, Federico; Chiaradia, Massimo; Gerdes, Axel; Martinez, Margarita Lopez; Ghorbani, Ghasem; Nasrabady, Mohsen

    2016-04-01

    A major magmatic flare-up is documented along the Bitlis-Zagros suture zone in Eocene-Oligocene times. The Cenozoic magmatism of intraplate Central Iran is an integrant part of this tectono-magmatic scenario. The Cenozoic magmatism of the Sabzevar structural zone consists of mostly intermediate to felsic intrusions and volcanic products. These igneous rocks have calc-alkaline and adakitic geochemical signatures, with nearly coincident zircon U-Pb and mica Ar-Ar ages of ca. 45 Ma. Adakitic rocks have quite low HREE and high Sr/Y ratio, but share most of their geochemical features with the calc-alkaline rocks. The Sabzevar volcanic rocks have similar initial Sr, Nd and Pb isotope ratios, showing their cogenetic nature. Nd model ages cluster tightly around ~ 0.2-0.3 Ga. The geochemistry of the Sabzevar volcanic rocks, along with their isotopic signatures, might strangle that an upper mantle source, metasomatized by slab-derived melts was involved in generating the Sabzevar calc-alkaline rocks. A bulk rock trace element modeling suggests that amphibole-plagioclase-titanite-dominated replenishment-fractional crystallization (RFC) is further responsible for the formation of the middle Eocene Sabzevar adakitic rocks. Extensional tectonics accompanied by lithospheric delamination, possibly assisted by slab break-off and melting at depth was responsible for the Eocene formation of the Sabzevar magmatic rocks and, more in general, for the magmatic "flare-up" in Iran.

  4. Relationship between volcanism and marine sedimentation in northern Austral (Aisén) Basin, central Patagonia: Stratigraphic, U-Pb SHRIMP and paleontologic evidence

    Science.gov (United States)

    Suárez, M.; De La Cruz, R.; Aguirre-Urreta, B.; Fanning, M.

    2009-04-01

    The northernmost part of the oil-producing Austral Basin, known as Aisén Basin or Río Mayo Embayment (in central Patagonian Cordillera; 43-46°S), is a special area within the basin where the interplay between volcanism and the initial stages of its development can be established. Stratigraphic, paleontologic and five new U-Pb SHRIMP age determinations presented here indicate that the Aisén Basin was synchronous with the later phases of volcanism of the Ibáñez Formation for at least 11 m.yr. during the Tithonian to early Hauterivian. In this basin marine sedimentary rocks of the basal units of the Coihaique Group accumulated overlying and interfingering with the Ibáñez Formation, which represents the youngest episode of volcanism of a mainly Jurassic acid large igneous province (Chon Aike Province). Five new U-Pb SHRIMP magmatic ages ranging between 140.3 ± 1.0 and 136.1 ± 1.6 Ma (early Valanginian to early Hauterivian) were obtained from the Ibáñez Formation whilst ammonites from the overlying and interfingering Toqui Formation, the basal unit of the Coihaique Group, indicate Tithonian, early Berriasian and late Berriasian ages. The latter was a synvolcanic shallow marine facies accumulated in an intra-arc setting, subsequently developed into a retro-arc basin.

  5. Petrographic characterization and preliminary geochronologic data from volcanic rocks of the Iriri formation, southern-central portion of the Amazon Craton, Aripuana - Mato Grosso

    International Nuclear Information System (INIS)

    The Moriru area is located in the south-central portion of the Amazon Craton, near the border of Mato Grosso and Amazonas states. The research was carried out using eight drill cores, 200 meters deep in average. The description of these drill cores allowed the identification of felsic lavas and pyroclastics inter layered with mafic flows volcanoclastic and sedimentary rocks. Granitic intrusions are completely altered by hydrothermal metamorphism. Later stage dikes were identified. The pyroclastic successions is characterized by ignimbritic rocks generated by pumice flows. The ignimbrites are enriched in pumice and phenocrysts and are classified as crystal enriched ignimbrite. The content of fine particles is low and the welding grade ranges from good to medium. The composition of ignimbrites is rhyodacite to dacite. U-Pb zircon ages are 1801+- 11 Ma for ignimbrites and 1848+-9 Ma for mafic volcanics. However, for the mafic rocks age may represent some inherited zircon. More data from these rocks are necessary before we can make a definitive conclusion. The air fall deposits are represented by ash tuff enriched in vitroclasts. The volcanogenic sedimentary deposits occur inter layered with pyroclastic deposits and are represented by volcanoclastic conglomerates and immature tuffaceous sandstones. The volcanic particles in this sequence, partially maintain igneous characteristics, which suggests small amount of reworking and a possible proximity to the source. Sulfides occur disseminated in sub-volcanic and in late-stage quartz-carbonate-chlorite veins. (author)

  6. Imaging of the fetal central nervous system

    NARCIS (Netherlands)

    Pistorius, L.R.

    2008-01-01

    Introduction : Ultrasound and MR imaging of the fetal central nervous system (CNS) develop at an ever-increasing rate. Theoretically, the two modalities should be synergistic, but a literature review revealed the difficulties of determining the merit of either technique and revealed gaps in our know

  7. Exercise, Stress Resistance, and Central Serotonergic Systems

    OpenAIRE

    Greenwood, Benjamin N.; Fleshner, Monika

    2011-01-01

    Voluntary exercise reduces the incidence of stress-related psychiatric disorders in humans and prevents serotonin-dependent behavioral consequences of stress in rodents. Evidence reviewed herein is consistent with the hypothesis that exercise increases stress resistance by producing neuroplasticity at multiple sites of the central serotonergic system, which all help to limit the behavioral impact of acute increases in serotonin during stressor exposure.

  8. Hypersensitivity Responses in the Central Nervous System

    DEFF Research Database (Denmark)

    Khorooshi, Reza; Asgari, Nasrin; Mørch, Marlene Thorsen;

    2015-01-01

    of pathology in neuromyelitis optica (NMO), a central nervous system (CNS) demyelinating disease where activated neutrophils infiltrate, unlike in MS. The most widely used model for MS, experimental autoimmune encephalomyelitis, is an autoantigen-immunized disease that can be transferred to naive animals...

  9. Azole-Resistant Central Nervous System Aspergillosis

    NARCIS (Netherlands)

    J.W.M. van der Linden; R.R. Jansen; D. Bresters; C.E. Visser; S.E. Geerlings; E.J. Kuijper; W.J.G. Melchers; P.E. Verweij

    2009-01-01

    Three patients with central nervous system aspergillosis due to azole-resistant Aspergillus fumigatus (associated with a leucine substitution for histidine at codon 98 [L98H] and a 34-base pair repeat in tandem in the promoter region) are described. The patients were treated with combination therapy

  10. Azole-resistant central nervous system aspergillosis.

    NARCIS (Netherlands)

    Linden, J.W.M. van der; Jansen, R.R.; Bresters, D.; Visser, C.E.; Geerlings, S.E.; Kuijper, E.J.; Melchers, W.J.G.; Verweij, P.E.

    2009-01-01

    Three patients with central nervous system aspergillosis due to azole-resistant Aspergillus fumigatus (associated with a leucine substitution for histidine at codon 98 [L98H] and a 34-base pair repeat in tandem in the promoter region) are described. The patients were treated with combination therapy

  11. Transition from alkaline to calc-alkaline volcanism during evolution of the Paleoproterozoic Francevillian basin of eastern Gabon (Western Central Africa)

    Science.gov (United States)

    Thiéblemont, Denis; Bouton, Pascal; Préat, Alain; Goujou, Jean-Christian; Tegyey, Monique; Weber, Francis; Ebang Obiang, Michel; Joron, Jean Louis; Treuil, Michel

    2014-11-01

    We report new geochemical data for the volcanic and subvolcanic rocks associated with the evolution of the Francevillian basin of eastern Gabon during Paleoproterozoic times (c. 2.1-2 Ga). Filling of this basin has proceeded through four main sedimentary or volcano-sedimentary episodes, namely FA, FB, FC and FD. Volcanism started during the FB episode being present only in the northern part of the basin (Okondja sub-basin). This volcanism is ultramafic to trachytic in composition and displays a rather constant alkaline geochemical signature. This signature is typical of a within-plate environment, consistent with the rift-setting generally postulated for the Francevillian basin during the FB period. Following FB, the FC unit is 10-20 m-thick silicic horizon (jasper) attesting for a massive input of silica in the basin. Following FC, the FD unit is a c. 200-400 m-thick volcano-sedimentary sequence including felsic tuffs and epiclastic rocks. The geochemical signatures of these rocks are totally distinct from those of the FB alkaline lavas. High Th/Ta and La/Ta ratios attest for a calc-alkaline signature and slight fractionation between heavy rare-earth suggests melting at a rather low pressure. Such characteristics are comparable to those of felsic lavas associated with the Taupo zone of New Zealand, a modern ensialic back-arc basin. Following FD, the FE detrital unit is defined only in the Okondja region, probably associated with a late-stage collapse of the northern part of the basin. It is suggested that the alkaline to calc-alkaline volcanic transition reflects the evolution of the Francevillian basin from a diverging to a converging setting, in response to the onset of converging movements in the Eburnean Belt of Central Africa.

  12. Geochemical variability of hydrothermal emissions between three Pacific volcanic arc systems: Alaskan-Aleutian and Cascadian, North America and Taupo Volcanic Zone, New Zealand

    Science.gov (United States)

    Blackstock, J. M.; Horton, T. W.; Gravley, D. M.; Deering, C. D.

    2013-12-01

    Knowledge of the source, transport, and fate of hydrothermal fluids in the upper crust informs our understanding and interpretation of ore-forming processes, volcanogenic hazards, geothermal resources, and volatile cycling. Co-variation between fluid inclusion CO2/CH4 and N2/Ar ratios is an established tracer of magmatic, meteoric, and crustal fluid end-members. Yet, this tracer has had limited application to macroscopic fluid reservoirs accessible via geothermal wells and hydrothermal features (e.g. pools). In this study, we compared the covariance CO2/CH4 and N2/Ar ratios of gases collected throughout the Taupo Volcanic Zone, New Zealand (TVZ), the Alaska-Aleutian Volcanic Arc, USA (AAVA), and the Cascadian Volcanic Arc, USA (CVA) with corresponding δ13C and 3He/4He values. Our findings show that there is good agreement between these proxies for different end-member contributions at coarse scales. However, some samples classified as meteoric water according to the CO2/CH4 and N2/Ar ratios also show more positive δ13C values (~ -7.0 per mil) and relatively higher 3He/4He ratios indicative of magmatic input from primarily mantle sources. This unexpected result may be related to magmatic fluids, CO2 in particular, mixing with predominantly meteoric derived waters. The potential to identify magmatic CO2 in groundwater samples overlying geothermal systems in differing volcanic arc settings using simple and cost-effective gas ratios is a promising step forward in the search for ';surface blind' but developable geothermal systems and volcanic monitoring. 3He/4He anomalies also support this inference and underscore the potential decoupling of thermal anomalies and magmatic-derived fluids in the Earth's crust. The general agreement between the co-variation of CO2/CH4 and N2/Ar ratios with other isotope and geochemical proxies for magmatic, meteoric, and crustal end-members is encouraging to employ expanded use of these ratios for both the exploration and monitoring of

  13. FINANCIAL CRISIS AND THE CENTRAL BANK SYSTEM

    Directory of Open Access Journals (Sweden)

    Richard POSPISIL

    2015-07-01

    Full Text Available The financial crisis that began in 2008 gradually developed into a global economic crisis and continues to this day. There is a lot of causes standing behind the creation, depth and process of the crisis, which is the deepest since the thirties of last centrury. One of the reasons can be found in the risky behavior of commercial banks, especially in the excessive lending of credits and mortgages. Its share on the financial crisis have central banks and their failure as the financial supervisory authority. But there is a lot of another causes of failures in the commercial banking system. And some of the causes lies outside the banking system and monetary policy. Its share of the blame has also become from state and its expenditure on the social policy.This article analyzes the role of the commercial banking system and the central banks on the financial crisis including prevention options and measures.

  14. Financial Crisis and the Central Bank System

    Directory of Open Access Journals (Sweden)

    RICHARD POSPISIL

    2015-05-01

    Full Text Available The financial crisis that began in 2008 gradually developed into a global economic crisis and continues to this day. There is a lot of causes standing behind the creation, depth and process of the crisis, which is the deepest since the thirties of last centrury. One of the reasons can be found in the risky behavior of commercial banks, especially in the excessive lending of credits and mortgages. Its share on the financial crisis have central banks and their failure as the financial supervisory authority. But there is a lot of another causes of failures in the commercial banking system. And some of the causes lies outside the banking system and monetary policy. Its share of the blame has also become from state and its expenditure on the social policy.This article analyzes the role of the commercial banking system and the central banks on the financial crisis including prevention options and measures.

  15. A first Event-tree for the Bárðarbunga volcanic system (Iceland): from the volcanic crisis in 2014 towards a tool for hazard assessment

    Science.gov (United States)

    Barsotti, Sara; Tumi Gudmundsson, Magnús; Jónsdottir, Kristín; Vogfjörd, Kristín; Larsen, Gudrun; Oddsson, Björn

    2015-04-01

    Bárdarbunga volcano is part of a large volcanic system that had its last confirmed eruption before the present unrest in 1910. This system is partially covered by ice within the Vatnajökull glacier and it extends further to the NNE as well as to SW. Based on historical data, its eruptive activity has been predominantly characterized by explosive eruptions, originating beneath the glacier, and important effusive eruptions in the ice-free part of the system itself. The largest explosive eruptions took place on the southern side of the fissure system in AD 1477 producing about 10 km3 of tephra. Due to the extension and location of this volcanic system, the range of potential eruptive scenarios and associated hazards is quite wide. Indeed, it includes: inundation, due to glacial outburst; tephra fallout, due to ash-rich plume generated by magma-water interaction; abundant volcanic gas release; and lava flows. Most importantly these phenomena are not mutually exclusive and might happen simultaneously, creating the premise for a wide spatial and temporal impact. During the ongoing volcanic crisis at Bárdarbunga, which started on 16 August, 2014, the Icelandic Meteorological Office, together with the University of Iceland and Icelandic Civil Protection started a common effort of drawing, day-by-day, the potential evolution of the ongoing rifting event and, based on the newest data from the monitoring networks, updated and more refined scenarios have been identified. Indeed, this volcanic crisis created the occasion for pushing forward the creation of the first Event-tree for the Bárðarbunga volcanic system. We adopted the approach suggested by Newhall and Pallister (2014) and a preliminary ET made of nine nodes has been constructed. After the two initial nodes (restless and genesis) the ET continues with the identification of the location of aperture of future eruptive vents. Due to the complex structure of the system and historical eruptions, this third node

  16. [Central nervous system tumors in pregnancy].

    Science.gov (United States)

    Podciechowski, Lech; Nowakowska, Dorota; Bielak, Adam; Nowosławska, Emilia; Szymański, Wojciech; Polis, Lech; Krasomski, Grzechorz; Fiks, Tomasz; Wilczyński, Jan

    2003-12-01

    Central nervous system tumour in pregnancy constitutes a serious complication. Considering frequent difficulties in diagnostics and therapy, the aim of the study was to present our experience in management with pregnant women with brain and spinal cord tumours. Between 1988-2000, in The Research Institute Polish Mother's Memorial Hospital in Lodzi, 4 pregnant women had been diagnosed with brain and spinal cord tumours. The incidence of tumours complicating pregnancy was 1/11460. Two patients diagnosed at 29 weeks' gestation, underwent craniotomy and tumour resection during pregnancy. Two other women with central nervous system tumours diagnosed at 39 weeks' gestation, were operated in the postpartum period. The analysis of the postoperative period, gestation and/or postpartum period in all women and well-being of their new-borns confirm undertaken medical decisions. PMID:15029742

  17. [Central nervous system malformations: neurosurgery correlates].

    Science.gov (United States)

    Jiménez-León, Juan C; Betancourt-Fursow, Yaline M; Jiménez-Betancourt, Cristina S

    2013-09-01

    Congenital malformations of the central nervous system are related to alterations in neural tube formation, including most of the neurosurgical management entities, dysraphism and craniosynostosis; alterations of neuronal proliferation; megalencefaly and microcephaly; abnormal neuronal migration, lissencephaly, pachygyria, schizencephaly, agenesis of the corpus callosum, heterotopia and cortical dysplasia, spinal malformations and spinal dysraphism. We expose the classification of different central nervous system malformations that can be corrected by surgery in the shortest possible time and involving genesis mechanisms of these injuries getting better studied from neurogenic and neuroembryological fields, this involves connecting innovative knowledge areas where alteration mechanisms in dorsal induction (neural tube) and ventral induction (telencephalization) with the current way of correction, as well as the anomalies of cell proliferation and differentiation of neuronal migration and finally the complex malformations affecting the posterior fossa and current possibilities of correcting them.

  18. Time perception mechanisms at central nervous system

    OpenAIRE

    Rhailana Fontes; Jéssica Ribeiro; Gupta, Daya S.; Dionis Machado; Fernando Lopes-Júnior; Francisco Magalhães; Victor Hugo Bastos; Kaline Rocha; Victor Marinho; Gildário Lima; Bruna Velasques; Pedro Ribeiro; Marco Orsini; Bruno Pessoa; Marco Antonio Araujo Leite

    2016-01-01

    The five senses have specific ways to receive environmental information and lead to central nervous system. The perception of time is the sum of stimuli associated with cognitive processes and environmental changes. Thus, the perception of time requires a complex neural mechanism and may be changed by emotional state, level of attention, memory and diseases. Despite this knowledge, the neural mechanisms of time perception are not yet fully understood. The objective is to relate the mechanisms...

  19. Tuberculoma of the central nervous system.

    Science.gov (United States)

    DeLance, Arthur R; Safaee, Michael; Oh, Michael C; Clark, Aaron J; Kaur, Gurvinder; Sun, Matthew Z; Bollen, Andrew W; Phillips, Joanna J; Parsa, Andrew T

    2013-10-01

    Tuberculosis is among the oldest and most devastating infectious diseases worldwide. Nearly one third of the world's population has active or latent disease, resulting in 1.5 million deaths annually. Central nervous system involvement, while rare, is the most severe form of tuberculosis. Manifestations include tuberculoma and tuberculous meningitis, with the majority of cases occurring in children and immunocompromised patients. Despite advancements in imaging and laboratory diagnostics, tuberculomas of the central nervous system remain a diagnostic challenge due to their insidious nature and nonspecific findings. On imaging studies tuberculous meningitis is characterized by diffuse basal enhancement, but tuberculomas may be indistinguishable from neoplasms. Early diagnosis is imperative, since clinical outcomes are largely dependent on timely treatment. Stereotactic biopsy with histopathological analysis can provide a definitive diagnosis, but is only recommended when non-invasive methods are inconclusive. Standard medical treatment includes rifampicin, isoniazid, pyrazinamide, and streptomycin or ethambutol. In cases of drug resistance, revision of the treatment regimen with second-line agents is recommended over the addition of a single drug to the first-line regimen. Advances in genomics have identified virulent strains of tuberculosis and are improving our understanding of host susceptibility. Neurosurgical referral is advised for patients with elevated intracranial pressure, seizures, or brain or spinal cord compression. This review synthesizes pertinent findings in the literature surrounding central nervous system tuberculoma in an effort to highlight recent advances in pathophysiology, diagnosis, and treatment.

  20. [Parasitic diseases of the central nervous system].

    Science.gov (United States)

    Schmutzhard, E

    2010-02-01

    Central nervous system infections and infestations by protozoa and helminths constitute a problem of increasing importance throughout all of central European and northern/western countries. This is partially due to the globalisation of our society, tourists and business people being more frequently exposed to parasitic infection/infestation in tropical countries than in moderate climate countries. On top of that, migrants may import chronic infestations and infections with parasitic pathogens, eventually also--sometimes exclusively--involving the nervous system. Knowledge of epidemiology, initial clinical signs and symptoms, diagnostic procedures as well as specific chemotherapeutic therapies and adjunctive therapeutic strategies is of utmost important in all of these infections and infestations of the nervous systems, be it by protozoa or helminths. This review lists, mainly in the form of tables, all possible infections and infestations of the nervous systems by protozoa and by helminths. Besides differentiating parasitic diseases of the nervous system seen in migrants, tourists etc., it is very important to have in mind that disease-related (e.g. HIV) or iatrogenic immunosuppression has led to the increased occurrence of a wide variety of parasitic infections and infestations of the nervous system (e. g. babesiosis, Chagas disease, Strongyloides stercoralis infestation, toxoplasmosis, etc.). PMID:20111855

  1. GPS-derived coupling estimates for the Central America subduction zone and volcanic arc faults: El Salvador, Honduras and Nicaragua

    Science.gov (United States)

    Correa-Mora, F.; DeMets, C.; Alvarado, D.; Turner, H. L.; Mattioli, G.; Hernandez, D.; Pullinger, C.; Rodriguez, M.; Tenorio, C.

    2009-12-01

    We invert GPS velocities from 32 sites in El Salvador, Honduras and Nicaragua to estimate the rate of long-term forearc motion and distributions of interseismic coupling across the Middle America subduction zone offshore from these countries and faults in the Salvadoran and Nicaraguan volcanic arcs. A 3-D finite element model is used to approximate the geometries of the subduction interface and strike-slip faults in the volcanic arc and determine the elastic response to coupling across these faults. The GPS velocities are best fit by a model in which the forearc moves 14-16 mmyr-1 and has coupling of 85-100 per cent across faults in the volcanic arc, in agreement with the high level of historic and recent earthquake activity in the volcanic arc. Our velocity inversion indicates that coupling across the potentially seismogenic areas of the subduction interface is remarkably weak, averaging no more than 3 per cent of the plate convergence rate and with only two poorly resolved patches where coupling might be higher along the 550-km-long segment we modelled. Our geodetic evidence for weak subduction coupling disagrees with a seismically derived coupling estimate of 60 +/- 10 per cent from a published analysis of earthquake damage back to 1690, but agrees with three other seismologic studies that infer weak subduction coupling from 20th century earthquakes. Most large historical earthquakes offshore from El Salvador and western Nicaragua may therefore have been intraslab normal faulting events similar to the Mw 7.3 1982 and Mw 7.7 2001 earthquakes offshore from El Salvador. Alternatively, the degree of coupling might vary with time. The evidence for weak coupling indirectly supports a recently published hypothesis that much of the Middle American forearc is escaping to the west or northwest away from the Cocos Ridge collision zone in Costa Rica. Such a hypothesis is particularly attractive for El Salvador, where there is little or no convergence obliquity to drive the

  2. The Central Nervous System of Box Jellyfish

    DEFF Research Database (Denmark)

    Garm, Anders Lydik; Ekström, Peter

    2008-01-01

    of behaviors in the box jellyfish such as obstacle avoidance and navigation. The need to process the visual information and turn it into the appropriate behavior puts strong demands on the nervous system of box jellyfish, which appears more elaborate than in other cnidarians. Here, the central part...... of this nervous system is described. Each rhopalium holds a separate part of the CNS with 1,000 nerve cells and a large amount of neuropil. The rhopalial nervous system has several subsystems defined by the anatomy, location, and immunocytochemistry of the cells. Most of the subsystems connect to one or more...... of the eye types, and it is likely that the rhopalial nervous system accounts for most of the visual processing. The major part of the CNS is made up of a ring nerve encircling the bell shaped body. The ring nerve holds around 10,000 cells and is directly connected to all four rhopalial nervous systems...

  3. Biogeochemical processes involving dissolved CO2 and CH4 at Albano, Averno, and Monticchio meromictic volcanic lakes (Central-Southern Italy)

    Science.gov (United States)

    Cabassi, Jacopo; Tassi, Franco; Vaselli, Orlando; Fiebig, Jens; Nocentini, Matteo; Capecchiacci, Francesco; Rouwet, Dmitri; Bicocchi, Gabriele

    2013-01-01

    This paper focuses on the chemical and isotopic features of dissolved gases (CH4 and CO2) from four meromictic lakes hosted in volcanic systems of Central-Southern Italy: Lake Albano (Alban Hills), Lake Averno (Phlegrean Fields), and Monticchio Grande and Piccolo lakes (Mt. Vulture). Deep waters in these lakes are characterized by the presence of a significant reservoir of extra-atmospheric dissolved gases mainly consisting of CH4 and CO2. The δ13C-CH4 and δD-CH4 values of dissolved gas samples from the maximum depths of the investigated lakes (from -66.8 to -55.6 ‰ V-PDB and from -279 to -195 ‰ V-SMOW, respectively) suggest that CH4 is mainly produced by microbial activity. The δ13C-CO2 values of Lake Grande, Lake Piccolo, and Lake Albano (ranging from -5.8 to -0.4 ‰ V-PDB) indicate a significant CO2 contribution from sublacustrine vents originating from (1) mantle degassing and (2) thermometamorphic reactions involving limestone, i.e., the same CO2 source feeding the regional thermal and cold CO2-rich fluid emissions. In contrast, the relatively low δ13C-CO2 values (from -13.4 to -8.2 ‰ V-PDB) of Lake Averno indicate a prevalent organic CO2. Chemical and isotopic compositions of dissolved CO2 and CH4 at different depths are mainly depending on (1) CO2 inputs from external sources (hydrothermal and/or anthropogenic); (2) CO2-CH4 isotopic exchange; and (3) methanogenic and methanotrophic activity. In the epilimnion, vertical water mixing, free oxygen availability, and photosynthesis cause the dramatic decrease of both CO2 and CH4 concentrations. In the hypolimnion, where the δ13C-CO2 values progressively increase with depth and the δ13C-CH4 values show an opposite trend, biogenic CO2 production from CH4 using different electron donor species, such as sulfate, tend to counteract the methanogenesis process whose efficiency achieves its climax at the water-bottom sediment interface. Theoretical values, calculated on the basis of δ13C-CO2 values, and

  4. An InSAR survey of the central Andes: Constraints on magma chamber geometry and mass balance in a volcanic arc

    Science.gov (United States)

    Pritchard, M. E.; Simons, M.

    2002-12-01

    The central Andes (14-28o S) has a high density of volcanoes, but a sparse human population, such that the activity of most volcanoes is poorly constrained. We use InSAR to conduct the first systematic observations of deformation at nearly 900 volcanoes (about 50 of which are classified ``potentially active'') during the 1992-2002 time interval. We find volcanic deformation in four locations. Subsidence is seen at Robledo (or Cerro Blanco) caldera, Argentina. We observe inflation at the stratovolcano Uturuncu, Bolivia, near stratovolcano Hualca Hualca, Peru, and in a region not associated with any known edifice on the border between Chile and Argentina that we call ``Lazufre'' because it lies between volcanoes Lastarria and Cordon del Azufre. The deformation pattern can be well explained by a uniform point-source source of inflation or deflation, but we compare these model results with those from a tri-axial point-source ellipsoid to test the robustness of estimated source depth and source strength (inferred here to be volume change). We further explore the sensitivity of these parameters to elastic half-space and layered-space models of crustal structure, and the influence of local topography. Because only one satellite look direction is available for most time periods, a variety of models are consistent with our observations. If we assume that inflation is due solely to magmatic intrusion, we can compare the rate of magma intrusion to volcanic extrusion during the decade for which data is available and the longer-term geologic rate. For the last decade, the ratio of volume intruded to extruded is between about 1-10, which agrees with previous geologic estimates in this and other volcanic arcs. The combined rate of intrusion and extrusion is within an order of magnitude of the inferred geologic rate.

  5. 40Ar/39Ar geochronology and geochemical reconnaissance of the Eocene Lowland Creek volcanic field, west-central Montana

    Science.gov (United States)

    Dudas, F.O.; Ispolatov, V.O.; Harlan, S.S.; Snee, L.W.

    2010-01-01

    We report geochronological and geochemical data for the calc-alkalic Lowland Creek volcanic field (LCVF) in westcentral Montana. 40Ar/ 39Ar age determinations show that the LCVF was active from 52.9 to 48.6 Ma, with tuff-forming eruptions at 52.9 ?? 0.14 and 51.8 ?? 0.14 Ma. These dates span the age range of vigorous Eocene igneous activity in the Kamloops-Absaroka-Challis belt. The LCVF evolved upward from basal rhyolites (SiO 2>71 wt%) to dacites and andesites (SiO 2 > 62 wt%). Compositional change parallels a transition from early explosive volcanism to late effusive activity. Four geochemical components can be detected in the rocks. A component with 206Pb/204Pb 18.3 and epsilon;Nd>-9 contain a third component; and an andesite with low Nd content and epsilon;Nd near-9 probably contains a fourth component. The first three components probably derive from the lower and middle crust, whereas the fourth is probably from the lithospheric mantle. ?? 2010 by The University of Chicago.

  6. Tephrochronology of the Mont-Dore volcanic Massif (Massif Central, France): new 40Ar/39Ar constraints on the Late Pliocene and Early Pleistocene activity

    Science.gov (United States)

    Nomade, Sébastien; Pastre, Jean-François; Nehlig, Pierre; Guillou, Hervé; Scao, Vincent; Scaillet, Stéphane

    2014-03-01

    The Mont-Dore Massif (500 km2), the youngest stratovolcano of the French Massif Central, consists of two volcanic edifices: the Guéry and the Sancy. To improve our knowledge of the oldest explosive stages of the Mont-Dore Massif, we studied 40Ar/39Ar-dated (through single-grain laser and step-heating experiments) 11 pyroclastic units from the Guéry stratovolcano. We demonstrate that the explosive history of the Guéry can be divided into four cycles of explosive eruption activity between 3.09 and 1.46 Ma (G.I to G.IV). We have also ascertained that deposits associated with the 3.1-3.0-Ma rhyolitic activity, which includes the 5-km3 "Grande Nappe" ignimbrite, are not recorded in the central part of the Mont-Dore Massif. All the pyroclastites found in the left bank of the Dordogne River belong to a later explosive phase (2.86-2.58 Ma, G.II) and were channelled down into valleys or topographic lows where they are currently nested. This later activity also gave rise to most of the volcanic products in the Perrier Plateau (30 km east of the Mont-Dore Massif); three quarters of the volcano-sedimentary sequence (up to 100 m thick) was emplaced within less than 20 ky, associated with several flank collapses in the northeastern part of the Guéry. The age of the "Fournet flora" (2.69 ± 0.01 Ma) found within an ash bed belonging to G.II suggests that temperate forests already existed in the French Massif Central before the Pliocene/Pleistocene boundary. The Guéry's third explosive eruption activity cycle (G.III) lasted between 2.36 and 1.91 Ma. It encompassed the Guéry Lake and Morangie pumice and ash deposits, as well as seven other important events recorded as centimetric ash beds some 60 to 100 km southeast of the Massif in the Velay region. We propose a general tephrochronology for the Mont-Dore stratovolcano covering the last 3.1 My. This chronology is based on 44 40Ar/39Ar-dated events belonging to eight explosive eruption cycles each lasting between 100 and 200

  7. Experimental Observations of Multiscale Dynamics of Viscous Fluid Behavior: Implications in Volcanic Systems

    Science.gov (United States)

    Arciniega-Ceballos, A.; Spina, L.; Scheu, B.; Dingwell, D. B.

    2015-12-01

    We have investigated the dynamics of Newtonian fluids with viscosities (10-1000 Pa s; corresponding to mafic to intermediate silicate melts) during slow decompression, in a Plexiglas shock tube. As an analogue fluid we used silicon oil saturated with Argon gas for 72 hours. Slow decompression, dropping from 10 MPa to ambient pressure, acts as the excitation mechanism, initiating several processes with their own distinct timescales. The evolution of this multi-timescale phenomenon generates complex non-stationary microseismic signals, which have been recorded with 7 high-dynamic piezoelectric sensors located along the conduit. Correlation analysis of these time series with the associated high-speed imaging enables characterization of distinct phases of the dynamics of these viscous fluids and the extraction of the time and the frequency characteristics of the individual processes. We have identified fluid-solid elastic interaction, degassing, fluid mass expansion and flow, bubble nucleation, growth, coalescence and collapse, foam building and vertical wagging. All these processes (in fine and coarse scales) are sequentially coupled in time, occur within specific pressure intervals, and exhibit a localized distribution in space. Their coexistence and interactions constitute the stress field and driving forces that determine the dynamics of the system. Our observations point to the great potential of this experimental approach in the understanding of volcanic processes and volcanic seismicity.

  8. Primary volcanic structures from a type section of Deccan Trap flows around Narsingpur–Harrai–Amarwara, central India: Implications for cooling history

    Indian Academy of Sciences (India)

    Piyali Sengupta; Arijit Ray

    2006-12-01

    Field investigations of the Deccan Trap lava sequence along a 70 km traverse in the Narsingpur–Harrai–Amarwara area of central India indicate twenty lava flows comprising a total thickness of around 480m. Primary volcanic structures like vesicles and cooling joints are conspicuous in this volcanic succession and are used to divide individual flows into three well-defined zones namely the lower colonnade zone, entablature zone, and the upper colonnade zone. The variable nature of these structural zones is used for identification and correlation of lava flows in the field. For twenty lava flows, the thicknesses of upper colonnade zones of eight flows are ∼5m while those of eight other flows are ∼8m each. The thicknesses of upper colonnade zones of remaining four flows could not be measured in the field. Using the thicknesses of these upper colonnade zones and standard temperature-flow thickness-cooling time profiles for lava pile, the total cooling time of these sixteen Deccan Trap lava flows has been estimated at 12 to 15 years.

  9. Plants and the central nervous system.

    Science.gov (United States)

    Carlini, E A

    2003-06-01

    This review article draws the attention to the many species of plants possessing activity on the central nervous system (CNS). In fact, they cover the whole spectrum of central activity such as psychoanaleptic, psycholeptic and psychodysleptic effects, and several of these plants are currently used in therapeutics to treat human ailments. Among the psychoanaleptic (stimulant) plants, those utilized by human beings to reduce body weight [Ephedra spp. (Ma Huang), Paullinia spp. (guaraná), Catha edulis Forssk. (khat)] and plants used to improve general health conditions (plant adaptogens) were scrutinized. Many species of hallucinogenic (psychodysleptic) plants are used by humans throughout the world to achieve states of mind distortions; among those, a few have been used for therapeutic purposes, such as Cannabis sativa L., Tabernanthe iboga Baill. and the mixture of Psychotria viridis Ruiz and Pav. and Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton. Plants showing central psycholeptic activities, such as analgesic or anxiolytic actions (Passiflora incarnata L., Valeriana spp. and Piper methysticum G. Forst.), were also analysed.Finally, the use of crude or semipurified extracts of such plants instead of the active substances seemingly responsible for their therapeutic effect is discussed. PMID:12895668

  10. Metastatic neoplasms of the central nervous system

    International Nuclear Information System (INIS)

    Metastatic neoplasms to the central nervous system are often encountered in the practice of surgical neuropathology. It is not uncommon for patients with systemic malignancies to present to medical attention because of symptoms from a brain metastasis and for the tissue samples procured from these lesions to represent the first tissue available to study a malignancy from an unknown primary. In general surgical pathology, the evaluation of a metastatic neoplasm of unknown primary is a very complicated process, requiring knowledge of numerous different tumor types, reagents, and staining patterns. The past few years, however, have seen a remarkable refinement in the immunohistochemical tools at our disposal that now empower neuropathologists to take an active role in defining the relatively limited subset of neoplasms that commonly metastasize to the central nervous system. This information can direct imaging studies to find the primary tumor in a patient with an unknown primary, clarify the likely primary site of origin in patients who have small tumors in multiple sites without an obvious primary lesion, or establish lesions as late metastases of remote malignancies. Furthermore, specific treatments can begin and additional invasive procedures may be prevented if the neuropathologic evaluation of metastatic neoplasms provides information beyond the traditional diagnosis of ''metastatic neoplasm.'' In this review, differential cytokeratins, adjuvant markers, and organ-specific antibodies are described and the immunohistochemical signatures of metastatic neoplasms that are commonly seen by neuropathologists are discussed

  11. Central configurations, periodic orbits, and Hamiltonian systems

    CERN Document Server

    Llibre, Jaume; Simó, Carles

    2015-01-01

    The notes of this book originate from three series of lectures given at the Centre de Recerca Matemàtica (CRM) in Barcelona. The first one is dedicated to the study of periodic solutions of autonomous differential systems in Rn via the Averaging Theory and was delivered by Jaume Llibre. The second one, given by Richard Moeckel, focusses on methods for studying Central Configurations. The last one, by Carles Simó, describes the main mechanisms leading to a fairly global description of the dynamics in conservative systems. The book is directed towards graduate students and researchers interested in dynamical systems, in particular in the conservative case, and aims at facilitating the understanding of dynamics of specific models. The results presented and the tools introduced in this book include a large range of applications.

  12. Central Nervous System Involvement by Multiple Myeloma

    DEFF Research Database (Denmark)

    Jurczyszyn, A.; Gozzetti, A.; Cerase, A.;

    2015-01-01

    Introduction: Central nervous system (CNS) involvement by multiple myeloma (MM) is a rare occurrence and is found in approximately 1% of MM patients at some time during the course of their disease. At the time of diagnosis, extramedullary MM is found in 7% of patients, and another 6% may develop....... Results: The median time from MM diagnosis to CNS MM diagnosis was 3 years. Upon diagnosis, 97% patients with CNS MM received frontline therapy, of which 76% received systemic therapy, 36% radiotherapy and 32% intrathecal therapy. The most common symptoms at presentation were visual changes (36...... history of chemotherapy and unfavorable cytogenetic profile, survival of individuals free from these negative prognostic factors can be prolonged due to administration of systemic treatment and/or radiotherapy. Prospective multi-institutional studies are warranted to improve the outcome of patients...

  13. Central nervous system involvement by multiple myeloma

    DEFF Research Database (Denmark)

    Jurczyszyn, Artur; Grzasko, Norbert; Gozzetti, Alessandro;

    2016-01-01

    The multicenter retrospective study conducted in 38 centers from 20 countries including 172 adult patients with CNS MM aimed to describe the clinical and pathological characteristics and outcomes of patients with multiple myeloma (MM) involving the central nervous system (CNS). Univariate......, 97% patients received initial therapy for CNS disease, of which 76% received systemic therapy, 36% radiotherapy and 32% intrathecal therapy. After a median follow-up of 3.5 years, the median overall survival (OS) from the onset of CNS involvement for the entire group was 7 months. Untreated...... untreated patients and patients with favorable cytogenetic profile might be prolonged due to systemic treatment and/or radiotherapy. This article is protected by copyright. All rights reserved....

  14. Central Nervous System Complications of Oncologic Therapy.

    Science.gov (United States)

    Hoeffner, Ellen G

    2016-08-01

    Traditional and newer agents used to treat cancer can cause significant toxicity to the central nervous system. MRI of the brain and spine is the imaging modality of choice for patients with cancer who develop neurologic symptoms. It is important to be aware of the agents that can cause neurotoxicity and their associated imaging findings so that patients are properly diagnosed and treated. In some instances conventional MRI may not be able to differentiate posttreatment effects from disease progression. In these instances advanced imaging techniques may be helpful, although further research is still needed. PMID:27444003

  15. Geochemical and visual indicators of hydrothermal fluid flow through a sediment-hosted volcanic ridge in the Central Bransfield Basin (Antarctica.

    Directory of Open Access Journals (Sweden)

    Alfred Aquilina

    Full Text Available In the austral summer of 2011 we undertook an investigation of three volcanic highs in the Central Bransfield Basin, Antarctica, in search of hydrothermal activity and associated fauna to assess changes since previous surveys and to evaluate the extent of hydrothermalism in this basin. At Hook Ridge, a submarine volcanic edifice at the eastern end of the basin, anomalies in water column redox potential (E(h were detected close to the seafloor, unaccompanied by temperature or turbidity anomalies, indicating low-temperature hydrothermal discharge. Seepage was manifested as shimmering water emanating from the sediment and from mineralised structures on the seafloor; recognisable vent endemic fauna were not observed. Pore fluids extracted from Hook Ridge sediment were depleted in chloride, sulfate and magnesium by up to 8% relative to seawater, enriched in lithium, boron and calcium, and had a distinct strontium isotope composition ((87Sr/(86Sr = 0.708776 at core base compared with modern seawater ((87Sr/(86Sr ≈ 0.70918, indicating advection of hydrothermal fluid through sediment at this site. Biogeochemical zonation of redox active species implies significant moderation of the hydrothermal fluid with in situ diagenetic processes. At Middle Sister, the central ridge of the Three Sisters complex located about 100 km southwest of Hook Ridge, small water column E(h anomalies were detected but visual observations of the seafloor and pore fluid profiles provided no evidence of active hydrothermal circulation. At The Axe, located about 50 km southwest of Three Sisters, no water column anomalies in E(h, temperature or turbidity were detected. These observations demonstrate that the temperature anomalies observed in previous surveys are episodic features, and suggest that hydrothermal circulation in the Bransfield Strait is ephemeral in nature and therefore may not support vent biota.

  16. Intercomparison of SO2 camera systems for imaging volcanic gas plumes

    Science.gov (United States)

    Kern, Christoph; Lübcke, Peter; Bobrowski, Nicole; Campion, Robin; Mori, Toshiya; Smekens, Jean-François; Stebel, Kerstin; Tamburello, Giancarlo; Burton, Mike; Platt, Ulrich; Prata, Fred

    2015-07-01

    SO2 camera systems are increasingly being used to image volcanic gas plumes. The ability to derive SO2 emission rates directly from the acquired imagery at high time resolution allows volcanic process studies that incorporate other high time-resolution datasets. Though the general principles behind the SO2 camera have remained the same for a number of years, recent advances in CCD technology and an improved understanding of the physics behind the measurements have driven a continuous evolution of the camera systems. Here we present an intercomparison of seven different SO2 cameras. In the first part of the experiment, the various technical designs are compared and the advantages and drawbacks of individual design options are considered. Though the ideal design was found to be dependent on the specific application, a number of general recommendations are made. Next, a time series of images recorded by all instruments at Stromboli Volcano (Italy) is compared. All instruments were easily able to capture SO2 clouds emitted from the summit vents. Quantitative comparison of the SO2 load in an individual cloud yielded an intra-instrument precision of about 12%. From the imagery, emission rates were then derived according to each group's standard retrieval process. A daily average SO2 emission rate of 61 ± 10 t/d was calculated. Due to differences in spatial integration methods and plume velocity determination, the time-dependent progression of SO2 emissions varied significantly among the individual systems. However, integration over distinct degassing events yielded comparable SO2 masses. Based on the intercomparison data, we find an approximate 1-sigma precision of 20% for the emission rates derived from the various SO2 cameras. Though it may still be improved in the future, this is currently within the typical accuracy of the measurement and is considered sufficient for most applications.

  17. Intercomparison of SO2 camera systems for imaging volcanic gas plumes

    Science.gov (United States)

    Kern, Christoph; Lübcke, Peter; Bobrowski, Nicole; Campion, Robin; Mori, Toshiya; Smekens, Jean-Francois; Stebel, Kerstin; Tamburello, Giancarlo; Burton, Mike; Platt, Ulrich; Prata, Fred

    2015-01-01

    SO2 camera systems are increasingly being used to image volcanic gas plumes. The ability to derive SO2 emission rates directly from the acquired imagery at high time resolution allows volcanic process studies that incorporate other high time-resolution datasets. Though the general principles behind the SO2 camera have remained the same for a number of years, recent advances in CCD technology and an improved understanding of the physics behind the measurements have driven a continuous evolution of the camera systems. Here we present an intercomparison of seven different SO2 cameras. In the first part of the experiment, the various technical designs are compared and the advantages and drawbacks of individual design options are considered. Though the ideal design was found to be dependent on the specific application, a number of general recommendations are made. Next, a time series of images recorded by all instruments at Stromboli Volcano (Italy) is compared. All instruments were easily able to capture SO2 clouds emitted from the summit vents. Quantitative comparison of the SO2 load in an individual cloud yielded an intra-instrument precision of about 12%. From the imagery, emission rates were then derived according to each group's standard retrieval process. A daily average SO2 emission rate of 61 ± 10 t/d was calculated. Due to differences in spatial integration methods and plume velocity determination, the time-dependent progression of SO2 emissions varied significantly among the individual systems. However, integration over distinct degassing events yielded comparable SO2 masses. Based on the intercomparison data, we find an approximate 1-sigma precision of 20% for the emission rates derived from the various SO2 cameras. Though it may still be improved in the future, this is currently within the typical accuracy of the measurement and is considered sufficient for most applications.

  18. Drilling of Submarine Shallow-water Hydrothermal Systems in Volcanic Arcs of the Tyrrhenian Sea, Italy

    Science.gov (United States)

    Petersen, S.; Augustin, N.; de Benedetti, A.; Esposito, A.; Gaertner, A.; Gemmell, B.; Gibson, H.; He, G.; Huegler, M.; Kleeberg, R.; Kuever, J.; Kummer, N. A.; Lackschewitz, K.; Lappe, F.; Monecke, T.; Perrin, K.; Peters, M.; Sharpe, R.; Simpson, K.; Smith, D.; Wan, B.

    2007-12-01

    Seafloor hydrothermal systems related to volcanic arcs are known from several localities in the Tyrrhenian Sea in water depths ranging from 650 m (Palinuro Seamount) to less than 50 m (Panarea). At Palinuro Seamount 13 holes (holes ended in mineralization. Metal enrichment at the top of the deposit is evident in some cores with polymetallic (Zn, Pb, Ag) sulfides overlying more massive and dense pyritic ore. The massive sulfide mineralization at Palinuro Seamount contains a number of unusual minerals, including enargite, tennantite, luzonite, and Ag-sulfosalts, that are not commonly encountered in mid-ocean ridge massive sulfides. In analogy to epithermal deposits forming on land, the occurrence of these minerals suggests a high sulfidation state of the hydrothermal fluids during deposition implying that the mineralizing fluids were acidic and oxidizing rather than near-neutral and reducing as those forming typical base metal rich massive sulfides along mid-ocean ridges. Oxidizing conditions during sulfide deposition can probably be related to the presence of magmatic volatiles in the mineralizing fluids that may be derived from a degassing magma chamber. Elevated temperatures within sediment cores and TV-grab stations (up to 60°C) indicate present day hydrothermal fluid flow. This is also indicated by the presence of small tube-worm bushes present on top the sediment. A number of drill holes were placed around the known phreatic gas-rich vents of Panarea and recovered intense clay-alteration in some holes as well as abundant massive anhydrite/gypsum with only trace sulfides along a structural depression suggesting the presence of an anhydrite seal to a larger hydrothermal system at depth. The aim of this study is to understand the role that magmatic volatiles and phase separation play in the formation of these precious and trace element-rich shallow water (<750m) hydrothermal systems in the volcanic arcs of the Tyrrhenian Sea.

  19. Distributed generation and centralized power system in Thailand

    DEFF Research Database (Denmark)

    Sukkumnoed, Decharut

    The paper examines and discusses conflicts between the development of distributed power and centralized power system in Thailand.......The paper examines and discusses conflicts between the development of distributed power and centralized power system in Thailand....

  20. Vasculitis Syndromes of the Central and Peripheral Nervous Systems

    Science.gov (United States)

    ... About NINDS Vasculitis Syndromes of the Central and Peripheral Nervous Systems Fact Sheet See a list of all NINDS ... 496-5717 "Vasculitis Syndromes of the Central and Peripheral Nervous Systems Fact Sheet", NINDS, Publication date July 2011. NIH ...

  1. Resources Centralization System for Grid Resources

    Directory of Open Access Journals (Sweden)

    Zahraa F. Muhsem

    2013-09-01

    Full Text Available The increasing expansion of communications that is characterized by quality and availability led to interest on grid computing paradigm. The grid computing solves large-scale scientific problems, by providing the feature of sharing and selecting of various resources accessibility and utility. These resources solve intensive problems by increasing the computation and storage power. This study focuses on system with centralized resources for managing the grid resources. The proposed idea will create a resource list, which includes the resource history that will help the user to search for resources. The proposal resources list system will improve the resource serving by showing the most resources used and will save the time search time for the job request, by these points we will improve the quality of the user jobs execution and the quality type of the used resources.

  2. Central nervous system lupus erythematosus in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Shumpei; Kimura, Kazue; Yoshida, Naotaka; Mitsuda, Toshihiro; Ibe, Masa-aki; Shimizu, Hiroko (Yokohama City Univ. (Japan). Faculty of Medicine)

    1989-12-01

    Clinical features of central nervous system (CNS) invlvement in childhood systemic lupus erythematosus (SLE) was investigated. Neuropsychiatric manifestations including seizures, chorea, headache, overt psychosis, tremor, increase of muscle spastisity, and disturbed memory were found in 47% of 15 patients with SLE. There was a well correlatin between CNS abnormalities and SLE disease activity judged by serum complement levels and anti-nuclear antibody and anti-DNA antibody titers. The administration of Prednisolon was effective for the treatment of these CNS abnormalities and steroid psychosis was rare in the present study. EEG abnormalities involving diffuse slowing and slowing bursts were found in 73% of the patients. Cranial CT scan revealed basel ganglia calcifications in 2 patients, and marked brain atrophy in 3 patients. This study indicated that in the long term following of SLE children CNS abnormalities need to be serially checked by EEG and cranial CT scans as well as serological investigations. (author).

  3. Catastrophic volcanism

    Science.gov (United States)

    Lipman, Peter W.

    1988-01-01

    Since primitive times, catastrophes due to volcanic activity have been vivid in the mind of man, who knew that his activities in many parts of the world were threatened by lava flows, mudflows, and ash falls. Within the present century, increasingly complex interactions between volcanism and the environment, on scales not previously experienced historically, have been detected or suspected from geologic observations. These include enormous hot pyroclastic flows associated with collapse at source calderas and fed by eruption columns that reached the stratosphere, relations between huge flood basalt eruptions at hotspots and the rifting of continents, devastating laterally-directed volcanic blasts and pyroclastic surges, great volcanic-generated tsunamis, climate modification from volcanic release of ash and sulfur aerosols into the upper atmosphere, modification of ocean circulation by volcanic constructs and attendent climatic implications, global pulsations in intensity of volcanic activity, and perhaps triggering of some intense terrestrial volcanism by planetary impacts. Complex feedback between volcanic activity and additional seemingly unrelated terrestrial processes likely remains unrecognized. Only recently has it become possible to begin to evaluate the degree to which such large-scale volcanic processes may have been important in triggering or modulating the tempo of faunal extinctions and other evolutionary events. In this overview, such processes are examined from the viewpoint of a field volcanologist, rather than as a previous participant in controversies concerning the interrelations between extinctions, impacts, and volcanism.

  4. Hydrothermal fluids vented at shallow depths at the Aeolian islands: relationships with volcanic and geothermal systems.

    Science.gov (United States)

    Italiano, Francesco; Caracausi, Antonio; Longo, Manfredi; Maugeri, Roberto; Paonita, Antonio

    2010-05-01

    volcanoes (e.g. Vulcano and Panarea). The explanation of such a difference is not related to the volcanic activity at all, but to the parent mantle that in the western side looks to be less contaminated compared to the eastern side. Crustal contamination has been invoked by several authors as the main factor that caused the dramatic 3He/4He decrease. Although the parent mantle produced magmas with different isotopic signature, the gas phase looks similar. To explain the results of the chemical analyses it is proposed that similar deep boundary conditions (pressure, temperature, oxidation level) act as buffers for the chemical composition of the venting gases. With the aim of investigating their origin, estimations of the deep equilibration conditions have been carried out. The reactive compounds detected in the sampled gases, largely used for geothermometric and geobarometric considerations of hydrothermal fluids were used in a system based on the CH4-CO-CO2 contents assuming the presence of a boiling aqueous solution. The equilibrium constants of the adopted reactions are a function of temperature and oxygen fugacity, being the latter buffered by the mineral assemblage of the host rocks. Due to the similarity in the chemical composition of the gases vented at all the islands, a theoretical model developed to interpret the chemical composition of the gases released at Panarea during the last volcanic crisis is here applied. The results have shown that geothermal boiling systems are detectable at all the islands with temperatures up to 350°C. The adopted geo-thermobarometric system is more sensitive to the contents of CO and CH4 than that of CO2, implying that although GWI induce modifications in the chemical composition, the estimated equilibrium temperatures do not change very much for variations of the CO2 content in the range of several volume percent, thus, whether or not the gaseous mixture underwent GWI. Moreover, the slow reaction kinetics of CO and CH4 allow them

  5. A dynamical systems view of network centrality.

    Science.gov (United States)

    Grindrod, Peter; Higham, Desmond J

    2014-05-01

    To gain insights about dynamic networks, the dominant paradigm is to study discrete snapshots, or timeslices, as the interactions evolve. Here, we develop and test a new mathematical framework where network evolution is handled over continuous time, giving an elegant dynamical systems representation for the important concept of node centrality. The resulting system allows us to track the relative influence of each individual. This new setting is natural in many digital applications, offering both conceptual and computational advantages. The novel differential equations approach is convenient for modelling and analysis of network evolution and gives rise to an interesting application of the matrix logarithm function. From a computational perspective, it avoids the awkward up-front compromises between accuracy, efficiency and redundancy required in the prevalent discrete-time setting. Instead, we can rely on state-of-the-art ODE software, where discretization takes place adaptively in response to the prevailing system dynamics. The new centrality system generalizes the widely used Katz measure, and allows us to identify and track, at any resolution, the most influential nodes in terms of broadcasting and receiving information through time-dependent links. In addition to the classical static network notion of attenuation across edges, the new ODE also allows for attenuation over time, as information becomes stale. This allows 'running measures' to be computed, so that networks can be monitored in real time over arbitrarily long intervals. With regard to computational efficiency, we explain why it is cheaper to track good receivers of information than good broadcasters. An important consequence is that the overall broadcast activity in the network can also be monitored efficiently. We use two synthetic examples to validate the relevance of the new measures. We then illustrate the ideas on a large-scale voice call network, where key features are discovered that are not

  6. The Role of Boron Chloride and noble gas isotope ratios in Taupo Volcanic Zone geothermal systems

    International Nuclear Information System (INIS)

    The model of the geothermal system in which deep circulating groundwater con noble gases, at air saturated water concentrations, mixes with hot fluids of man origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks 'en route' the surface. It is demonstrated that this interaction is responsible for most of CO/sub 2/ in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed th the modelling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks like to be encountered in the geothermal system, but further information on the behaviour of B may be needed. If these problems can be overcome this modelling technique has promise for the estimation of the recharge of geothermal systems a hence the sustainability of these systems. (author). 17 refs., 4 figs

  7. Volcanic pulses determined by local re-melting throughout plumbing systems

    Science.gov (United States)

    Di Renzo, V.; Moretti, R.; neuville, D. R.; Le Losq, C.; Allard, P.; Arienzo, I.; Civetta, L.; D'Antonio, M.; Flank, A.; Lagarde, P.; Metrich, N.; Orsi, G.; Papale, P.

    2012-12-01

    We present results from a thorough surveys of magma features from active southern Italy Volcanoes (Vesuvius, Campi Flegrei, Ischia, Stromboli) which are clearly related to a common subduction setting. In fact, the geochemical signatures of volcanic products from these sites show that their source regions are invested by melt/fluids released from the de-volatilizing slab. Volcanism at these volcanic sites is commonly seen as due to magmas ascending and differentiating from the parental melts originated in the mantle source. However, these volcanoes and their products, melt inclusions (MIs) particularly, show common features, such as: 1) a relatively modest magma production in recent times; 2) high total volatile contents and abundant gas emission at surface; 3) abundant CO2 in the gas phase coexisting with the melts at large depths, prior to any interaction with the carbonatic basement, if present; 4) CO2 fluxing of magmas; 5) vapor buffered trends bounding MIs on H2O-CO2 saturation diagrams; 6) evidences of isotopic disequilibria between minerals and melts; 7) high oxidation states also in deep mafic parental magmas, essentially governed by Fe2+/Fe3+ around 1; 8) relatively low-MgO contents of mafic parental magmas. All these features can be ascribed to multiple paths of magma mixing/mingling + degassing + fractional crystallization. Here we present a complementary hypothesis and suggest that the ascending slab-derived supercritical fluids may (re)melt pre-existing crystal mushes (e.g., Gaetani and Grove, 2003) at great crustal depths and then mobilize small batches of fluid-rich magmas, contributing to the above features. In this view, mafic magmas emitted at studied volcanoes during the last 10 ka could represent molten patches, formed under hydrous and oxidized conditions, of mush compositionally akin to mafic trachybasaltic rocks. Iron is in fact the most abundant multiple valence element within the mushy system, and during the fluid-driven melting at depth it

  8. Controlling Groudwater System by Pattern Fracture Approach in Subsurface Volcanic Deposit: Mt.Salak- Mt.Pangranggo, West Java, Indonesia

    Science.gov (United States)

    Endyana, Cipta; Hendarmawan; Sukiyah, Emmy; Ary Dharmawan, Irwan

    2016-01-01

    In general, the volcanic region has high potential of water resources. However, volcanic field are very complex in structure and texture of rock compared with sedimentary rocks. They also have different porosity in type and distribution, with the spread of the highly different within a short distance. Consequently, groundwater in this volcanic area is quite difficult to predict groundwater flow. Those rocks should be identified as vertical and lateral spreading. In fact, the groundwater a is not flowing in the volcanic rock pores only, but also flow in fractures that developed by the volcanic and tectonic processes. Ciherang area which is located between Mount Salak and Mount Gede-Pangrango and bypassed by tectonic faults, has a complex fracture pattern. The result of this fracture pattern research indicated that at least four pattern of fracture systems were developed. All fracture patterns were suggested in relation with the imposition of volcanic rocks. Groundwater in these fractures have to consider for water resources calculation. Therefore fracture media has become one of the important parameters in the calculation of water resources. The modelling of subsurface volcanic deposit was developed by resistivity value of rock deposits. They can describe the distribution of volcanic deposits until 150 meters below surface. The fracture that constantly developed up to certain depth will be exposed by contrast enhancement of resistivity model of rock deposits. Delineation of fracture pattern will be known which each fracture pattern is associated with the flow of groundwater. Furthermore, there are also fractures are influenced by tectonic faults, and fractures caused by both of the processes. Fractures with high intensity indicated direction of porous media have a trend with relatively north-south direction and the fracture which is constantly up to certain depth is indicated as a pathway of groundwater flow, but several fractures which are affected by tectonic

  9. On the behavior of site effects in Central Mexico (the Mexican Volcanic Belt – MVB), based on records of shallow earthquakes that occurred in the zone between 1998 and 2011

    OpenAIRE

    Clemente-Chavez, A.; Zúñiga, F. R.; Lermo, J.; A. Figueroa-Soto; Valdés, C.; M. Montiel; O. Chavez; Arroyo, M.

    2013-01-01

    The Mexican Volcanic Belt (MVB) is a seismogenic zone that transects the central part of Mexico with an east–west orientation. The risk and hazard seismic of this seismogenic zone has not been studied at detail due to the scarcity of instrumental data as well as because seismicity in the continental regimen of Central Mexico is not too frequent, however, it is known that there are precedents of large earthquakes (Mw > 6.0) that have taken place in this zone...

  10. Exupéry - a mobile fast response system for managing a volcanic crisis

    Science.gov (United States)

    Hort, M. K.

    2009-12-01

    Despite ever increasing efforts to monitor historically active volcanoes many of those are still very poorly or unmonitored, even in highly populated areas. In case of volcanic unrest or even a volcanic crisis evaluating the situation is therefore often very difficult due to the little information that is available for that specific volcano. Over the past decades several different programs have supported volcanic crisis management efforts in third world countries from sending experts all the way to improving or even installing new networks around the volcano. One of the main problems especially when quickly upgrading networks during a crisis is that each system usually comes with its own acquisition and processing system which makes it very difficult to manage the observational network and provide an interdisciplinary interpretation of the data with respect to the activity status of the volcano. Here we present a newly developed volcano fast response system which overcomes several of these shortcomings. The core of the system is a novel database (SEISHUB) that allows for the collection of data of various kinds, i.e. simple time series data like seismic data, gas measurements, GPS measurements, as well as satellite data (SO2 flux, thermal anomaly, ground deformation). Part of the collected data may also come from an already existing network. Data from new field instruments are transmitted through a wireless network that has been specifically designed for the volcano fast response system. One of the main difficulties with such a multidisciplinary data set is an easy access to the data. This is provided through a common Web based GIS interface which allows various datalayers being simultaneously accessed through a Web Browser. The underlying software is designed in such a way that it only uses open source software, so it can be easily installed on other systems not having to deal with purchasing proprietary software. Aside from this the system provides tools to

  11. An Early-Warning System for Volcanic Ash Dispersal: The MAFALDA Procedure

    Science.gov (United States)

    Barsotti, S.; Nannipieri, L.; Neri, A.

    2006-12-01

    Forecasts of the dispersal of volcanic ash is a fundamental goal in order to mitigate its potential impact on urbanized areas and transport routes surrounding explosive volcanoes. To this aim we developed an early- warning procedure named MAFALDA (Modeling And Forecasting Ash Loading and Dispersal in the Atmosphere). Such tool is able to quantitatively forecast the atmospheric concentration of ash as well as the ground deposition as a function of time over a 3D spatial domain.\\The main features of MAFALDA are: (1) the use of the hybrid Lagrangian-Eulerian code VOL-CALPUFF able to describe both the rising column phase and the atmospheric dispersal as a function of weather conditions, (2) the use of high-resolution weather forecasting data, (3) the short execution time that allows to analyse a set of scenarios and (4) the web-based CGI software application (written in Perl programming language) that shows the results in a standard graphical web interface and makes it suitable as an early-warning system during volcanic crises.\\MAFALDA is composed by a computational part that simulates the ash cloud dynamics and a graphical interface for visualizing the modelling results. The computational part includes the codes for elaborating the meteorological data, the dispersal code and the post-processing programs. These produces hourly 2D maps of aerial ash concentration at several vertical levels, extension of "threat" area on air and 2D maps of ash deposit on the ground, in addition to graphs of hourly variations of column height.\\The processed results are available on the web by the graphical interface and the users can choose, by drop-down menu, which data to visualize. \\A first partial application of the procedure has been carried out for Mt. Etna (Italy). In this case, the procedure simulates four volcanological scenarios characterized by different plume intensities and uses 48-hrs weather forecasting data with a resolution of 7 km provided by the Italian Air Force.

  12. Pediatric central nervous system vascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Burch, Ezra A. [Brigham and Women' s Hospital, Department of Radiology, Boston, MA (United States); Orbach, Darren B. [Boston Children' s Hospital, Neurointerventional Radiology, Boston, MA (United States)

    2015-09-15

    Pediatric central nervous system (CNS) vascular anomalies include lesions found only in the pediatric population and also the full gamut of vascular lesions found in adults. Pediatric-specific lesions discussed here include infantile hemangioma, vein of Galen malformation and dural sinus malformation. Some CNS vascular lesions that occur in adults, such as arteriovenous malformation, have somewhat distinct manifestations in children, and those are also discussed. Additionally, children with CNS vascular malformations often have associated broader vascular conditions, e.g., PHACES (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac anomalies, eye anomalies and sternal anomalies), hereditary hemorrhagic telangiectasia, and capillary malformation-arteriovenous malformation syndrome (related to the RASA1 mutation). The treatment of pediatric CNS vascular malformations has greatly benefited from advances in endovascular therapy, including technical advances in adult interventional neuroradiology. Dramatic advances in therapy are expected to stem from increased understanding of the genetics and vascular biology that underlie pediatric CNS vascular malformations. (orig.)

  13. Corticosteroids In Infections Of Central Nervous System

    Directory of Open Access Journals (Sweden)

    Meena AK

    2003-01-01

    Full Text Available Infections of central nervous system are still a major problem. Despite the introduction of newer antimicrobial agents, mortality and long-term sequelace associated with these infections is unacceptably high. Based on the evidence that proinflammtory cytokines have a role in pathophysiology of bacterial and tuberculous meningitis, corticosteroids with a potent anti-inflammatory and immunomodulating effect have been tested and found to be of use in experimental and clinical studies, Review of the available literature suggests steroid administration just prior to antimicrobial therapy is effective in decreasing audiologic and neurologic sequelae in childern with H. influenzae nenigitis. Steroid use for bacterial meningitis in adults is found to be beneficial in case of S. pneumoniae. The value of adjunctive steroid therapy for other bacterial causes of meningitis remains unproven. Corticocorticoids are found to be of no benefit in viral meningitis, Role of steroids in HIV positive patients needs to be studied.

  14. Scaffolds for central nervous system tissue engineering

    Science.gov (United States)

    He, Jin; Wang, Xiu-Mei; Spector, Myron; Cui, Fu-Zhai

    2012-03-01

    Traumatic injuries to the brain and spinal cord of the central nervous system (CNS) lead to severe and permanent neurological deficits and to date there is no universally accepted treatment. Owing to the profound impact, extensive studies have been carried out aiming at reducing inflammatory responses and overcoming the inhibitory environment in the CNS after injury so as to enhance regeneration. Artificial scaffolds may provide a suitable environment for axonal regeneration and functional recovery, and are of particular importance in cases in which the injury has resulted in a cavitary defect. In this review we discuss development of scaffolds for CNS tissue engineering, focusing on mechanism of CNS injuries, various biomaterials that have been used in studies, and current strategies for designing and fabricating scaffolds.

  15. Emerging infections of the central nervous system.

    Science.gov (United States)

    Lyons, Jennifer; McArthur, Justin

    2013-12-01

    Emerging infections affecting the central nervous system often present as encephalitis and can cause substantial morbidity and mortality. Diagnosis requires not only careful history taking, but also the application of newly developed diagnostic tests. These diseases frequently occur in outbreaks stemming from viruses that have mutated from an animal host and gained the ability to infect humans. With globalization, this can translate to the rapid emergence of infectious clusters or the establishment of endemicity in previously naïve locations. Since these infections are often vector borne and effective treatments are almost uniformly lacking, prevention is at least as important as prompt diagnosis and institution of supportive care. In this review, we focus on some of the recent literature addressing emerging and resurging viral encephalitides in the United States and around the world-specifically, West Nile virus, dengue, polio, and cycloviruses. We also discuss new, or "emerging," techniques for the precise and rapid diagnosis of encephalitides. PMID:24136412

  16. VIIP: Central Nervous System (CNS) Modeling

    Science.gov (United States)

    Vera, Jerry; Mulugeta, Lealem; Nelson, Emily; Raykin, Julia; Feola, Andrew; Gleason, Rudy; Samuels, Brian; Ethier, C. Ross; Myers, Jerry

    2015-01-01

    Current long-duration missions to the International Space Station and future exploration-class missions beyond low-Earth orbit expose astronauts to increased risk of Visual Impairment and Intracranial Pressure (VIIP) syndrome. It has been hypothesized that the headward shift of cerebrospinal fluid (CSF) and blood in microgravity may cause significant elevation of intracranial pressure (ICP), which in turn may then induce VIIP syndrome through interaction with various biomechanical pathways. However, there is insufficient evidence to confirm this hypothesis. In this light, we are developing lumped-parameter models of fluid transport in the central nervous system (CNS) as a means to simulate the influence of microgravity on ICP. The CNS models will also be used in concert with the lumped parameter and finite element models of the eye described in the related IWS works submitted by Nelson et al., Feola et al. and Ethier et al.

  17. Advances in Primary Central Nervous System Lymphoma.

    Science.gov (United States)

    Patrick, Lauren B; Mohile, Nimish A

    2015-12-01

    Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma that is limited to the CNS. Although novel imaging techniques aid in discriminating lymphoma from other brain tumors, definitive diagnosis requires brain biopsy, vitreoretinal biopsy, or cerebrospinal fluid analysis. Survival rates in clinical studies have improved over the past 20 years due to the addition of high-dose methotrexate-based chemotherapy regimens to whole-brain radiotherapy. Long-term survival, however, is complicated by clinically devastating delayed neurotoxicity. Newer regimens are attempting to reduce or eliminate radiotherapy from first-line treatment with chemotherapy dose intensification. Significant advances have also been made in the fields of pathobiology and treatment, with more targeted treatments on the horizon. The rarity of the disease makes conducting of prospective clinical trials challenging, requiring collaborative efforts between institutions. This review highlights recent advances in the biology, detection, and treatment of PCNSL in immunocompetent patients.

  18. The Olig family affects central nervous system development and disease

    Institute of Scientific and Technical Information of China (English)

    Botao Tan; Jing Yu; Ying Yin; Gongwei Jia; Wei Jiang; Lehua Yu

    2014-01-01

    Neural cell differentiation and maturation is a critical step during central nervous system devel-opment. The oligodendrocyte transcription family (Olig family) is known to be an important factor in regulating neural cell differentiation. Because of this, the Olig family also affects acute and chronic central nervous system diseases, including brain injury, multiple sclerosis, and even gliomas. Improved understanding about the functions of the Olig family in central nervous system development and disease will greatly aid novel breakthroughs in central nervous system diseases. This review investigates the role of the Olig family in central nervous system develop-ment and related diseases.

  19. GeoNetGIS: a Geodetic Network Geographical Information System to manage GPS networks in seismic and volcanic areas

    Science.gov (United States)

    Cristofoletti, P.; Esposito, A.; Anzidei, M.

    2003-04-01

    This paper presents the methodologies and issues involved in the use of GIS techniques to manage geodetic information derived from networks in seismic and volcanic areas. Organization and manipulation of different geodetical, geological and seismic database, give us a new challenge in interpretation of information that has several dimensions, including spatial and temporal variations, also the flexibility and brand range of tools available in GeoNetGIS, make it an attractive platform for earthquake risk assessment. During the last decade the use of geodetic networks based on the Global Positioning System, devoted to geophysical applications, especially for crustal deformation monitoring in seismic and volcanic areas, increased dramatically. The large amount of data provided by these networks, combined with different and independent observations, such as epicentre distribution of recent and historical earthquakes, geological and structural data, photo interpretation of aerial and satellite images, can aid for the detection and parameterization of seismogenic sources. In particular we applied our geodetic oriented GIS to a new GPS network recently set up and surveyed in the Central Apennine region: the CA-GeoNet. GeoNetGIS is designed to analyze in three and four dimensions GPS sources and to improve crustal deformation analysis and interpretation related with tectonic structures and seismicity. It manages many database (DBMS) consisting of different classes, such as Geodesy, Topography, Seismicity, Geology, Geography and Raster Images, administrated according to Thematic Layers. GeoNetGIS represents a powerful research tool allowing to join the analysis of all data layers to integrate the different data base which aid for the identification of the activity of known faults or structures and suggesting the new evidences of active tectonics. A new approach to data integration given by GeoNetGIS capabilities, allow us to create and deliver a wide range of maps, digital

  20. Inorganic particles in the skin of inhabitants of volcanic areas of Central America: their possible immunomodulatory influence in leishmaniasis and leprosy.

    Science.gov (United States)

    Convit, J; Ulrich, M; Castillo, J; De Lima, H; Pérez, M; Caballero, N; Hung, J; Arana, B; Pérez, P

    2006-08-01

    We have evaluated biopsies from patients with atypical nodular and typical ulcerated lesions of cutaneous leishmaniasis, from leishmanin reactions and skin from normal individuals from Nicaragua, Honduras and Guatemala for the presence of inorganic particles using confocal microscopy with a polarised light source and conventional histopathological techniques. Analysis by semiquantitative confocal microscopy permitted the demonstration of significantly larger numbers of particles in atypical lesions. Silica and aluminium, important components of these particles, were less abundant in particles from normal skin. The histology of these atypical lesions, characterised by 'naked' sarcoidal granulomas with epithelioid differentiation but very few lymphocytes, was very similar to the histological reaction observed after 14 days in persisting inflammation at leishmanin skin test sites. The presence of these unusual lesions in areas of Central American countries characterised by the presence of large amounts of volcanic ash, as well the unexpectedly low prevalence of leprosy in Central America, suggest that environmental factors may contribute significantly to the frequency and clinical manifestations of these infections. Among possible environmental features, the presence of inorganic particles with immunomodulatory properties in the skin may be a significant factor.

  1. Central nervous system toxicity of metallic nanoparticles

    Directory of Open Access Journals (Sweden)

    Feng XL

    2015-07-01

    Full Text Available Xiaoli Feng,1 Aijie Chen,1 Yanli Zhang,1 Jianfeng Wang,2 Longquan Shao,1 Limin Wei2 1Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China; 2School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, People’s Republic of China Abstract: Nanomaterials (NMs are increasingly used for the therapy, diagnosis, and monitoring of disease- or drug-induced mechanisms in the human biological system. In view of their small size, after certain modifications, NMs have the capacity to bypass or cross the blood–brain barrier. Nanotechnology is particularly advantageous in the field of neurology. Examples may include the utilization of nanoparticle (NP-based drug carriers to readily cross the blood–brain barrier to treat central nervous system (CNS diseases, nanoscaffolds for axonal regeneration, nanoelectromechanical systems in neurological operations, and NPs in molecular imaging and CNS imaging. However, NPs can also be potentially hazardous to the CNS in terms of nano­neurotoxicity via several possible mechanisms, such as oxidative stress, autophagy, and lysosome dysfunction, and the activation of certain signaling pathways. In this review, we discuss the dual effect of NMs on the CNS and the mechanisms involved. The limitations of the current research are also discussed. Keywords: nanomaterials, neurotoxicity, blood–brain barrier, autophagy, ROS

  2. Possible lava tube system in a hummocky lava flow at Daund, western Deccan Volcanic Province, India

    Indian Academy of Sciences (India)

    Raymond A Duraiswami; Ninad R Bondre; Gauri Dole

    2004-12-01

    A hummocky flow characterised by the presence of toes, lobes, tumuli and possible lava tube system is exposed near Daund, western Deccan Volcanic Province, India. The lava tube system is exposed as several exhumed outcrops and is composed of complex branching and discontinuous segments. The roof of the lava tube has collapsed but original lava tube walls and fragments of the tube roof are seen at numerous places along the tube. At some places the tube walls exhibit a single layer of lava lining, whereas, at other places it shows an additional layer characterised by smooth surface and polygonal cracks. The presence of a branching and meandering lava tube system in the Daund flow, which represents the terminal parts of Thakurwadi Formation, shows that the hummocky flow developed at a low local volumetric flow rate. This tube system developed in the thinner parts of the flow sequence; and tumuli developed in areas where the tube clogged temporarily in the sluggish flow.

  3. The Pliocene-Quaternary Buffalo Valley volcanic field, Nevada: Post-extension, intraplate magmatism in the north-central Great Basin, USA

    Science.gov (United States)

    Cousens, Brian; Wetmore, Stacey; Henry, Christopher D.

    2013-12-01

    The Buffalo Valley volcanic field consists of Pliocene through Quaternary lava flows and spatter cones located south of Battle Mountain and adjacent to the Fish Creek Mountains, north-central Nevada. The volcanic rocks are split into two groups by age and geochemistry. The Pliocene sequence (4.02 to 2.75 Ma) consists of olivine- and plagioclase-bearing alkali basaltic lava flows with minor pyroclastic deposits, found primarily along the south flank of Battle Mountain and also at the north end of the Fish Creek Mountains and within the Fish Creek Mountains caldera. The Quaternary series (1.99 to 1.14 Ma) includes nearly a dozen trachybasaltic spatter cones with short lava flows erupted along the northwest flank of the Fish Creek Mountains. Normalized rare earth element and incompatible element plots for both groups are light rare earth and Nb-Ta enriched, resembling alkali basalts from ocean islands, but the Quaternary lavas are more light rare earth element-enriched and cross the Pliocene basalt patterns at Eu. Radiogenic and stable isotope ratios are consistent with an asthenospheric mantle source, and the rare earth element patterns indicate a shift from melting in the spinel to garnet peridotite field with time. Basaltic rocks from other intraplate fields in the Great Basin, including the Lunar Crater and Cima fields, only include lavas that originated at depth in the garnet peridotite field. Buffalo Valley is located at the margin of a proposed lithospheric drip (delamination) and within a zone of lithospheric thinning that extends across northern Nevada, both of which may control where melting in the asthenosphere may occur. The proximity to the edge of Precambrian-Phanerozoic lithosphere boundary may also be a factor in melt generation.

  4. De-centralized and centralized control for realistic EMS Maglev systems

    Science.gov (United States)

    Moawad, Mohamed M. Aly M.

    A comparative study of de-centralized and centralized controllers when used with real EMS Maglev Systems is introduced. This comparison is divided into two parts. Part I is concerned with numerical simulation and experimental testing on a two ton six-magnet EMS Maglev vehicle. Levitation and lateral control with these controllers individually and when including flux feedback control in combination with these controllers to enhance stability are introduced. The centralized controller is better than the de-centralized one when the system is exposed to a lateral disturbing force such as wind gusts. The flux feedback control when combined with de-centralized or centralized controllers does improve the stability and is more resistant and robust with respect to the air gap variations. Part II is concerned with the study of Maglev vehicle-girder dynamic interaction system and the comparison between these two controllers on this typical system based on performance and ride quality achieved. Numerical simulations of the ODU EMS Maglev vehicle interacting with girder are conducted with these two different controllers. The de-centralized and centralized control for EMS Maglev systems that interact with a flexible girder provides similar ride quality. Centralized control with flux feedback could be the best controller for the ODU Maglev system when operating on girder. The centralized control will guarantee the suppression of the undesired lateral displacements; hence it will provide smoother ride quality. Flux feedback will suppress air gap variations due to the track discontinuities.

  5. Characterization of open and closed volcanic systems in Indonesia and Mexico using InSAR time series

    Science.gov (United States)

    Chaussard, E.; Amelung, F.; Aoki, Y.

    2013-08-01

    use 2007-2011 Advanced Land Observing Satellite (ALOS) data to perform an arc-wide interferometric synthetic aperture radar (InSAR) time series survey of the Trans-Mexican Volcanic Belt (TMVB) and to study time-dependent ground deformation of four Indonesian volcanoes selected following the 2007-2009 study of Chaussard and Amelung (2012). Our objectives are to examine whether arc volcanoes exhibit long-term edifice-wide cyclic deformation patterns that can be used to characterize open and closed volcanic systems and to better constrain in which cases precursory inflation is expected. We reveal deformation cycles at both regularly active and previously inactive Indonesian volcanoes, but we do not detect deformation in the TMVB, reflecting a lower activity level. We identify three types of relationships between deformation and activity: inflation prior to eruption and associated with or followed by deflation (Kerinci and Sinabung), inflation without eruption and followed by slow deflation (Agung), and eruption without precursory deformation (Merapi, Colima, and Popocatépetl; at Merapi, no significant deformation is detected even during eruption). The first two cases correspond to closed volcanic systems and suggest that the traditional model of magmatic systems and eruptive cycles do apply to andesitic volcanoes (i.e., inflation and deflation episodes associated with magma accumulation or volatile exsolution in a crustal reservoir followed by eruptions or in situ cooling). In contrast, the last case corresponds to open volcanic systems where no significant pressurization of the magmatic reservoirs is taking place prior to eruptions and thus no long-term edifice-wide ground deformation can be detected. We discuss these results in terms of InSAR's potential for forecasting volcanic unrest.

  6. Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland.

    Science.gov (United States)

    Sigmundsson, Freysteinn; Hooper, Andrew; Hreinsdóttir, Sigrún; Vogfjörd, Kristín S; Ófeigsson, Benedikt G; Heimisson, Elías Rafn; Dumont, Stéphanie; Parks, Michelle; Spaans, Karsten; Gudmundsson, Gunnar B; Drouin, Vincent; Árnadóttir, Thóra; Jónsdóttir, Kristín; Gudmundsson, Magnús T; Högnadóttir, Thórdís; Fridriksdóttir, Hildur María; Hensch, Martin; Einarsson, Páll; Magnússon, Eyjólfur; Samsonov, Sergey; Brandsdóttir, Bryndís; White, Robert S; Ágústsdóttir, Thorbjörg; Greenfield, Tim; Green, Robert G; Hjartardóttir, Ásta Rut; Pedersen, Rikke; Bennett, Richard A; Geirsson, Halldór; La Femina, Peter C; Björnsson, Helgi; Pálsson, Finnur; Sturkell, Erik; Bean, Christopher J; Möllhoff, Martin; Braiden, Aoife K; Eibl, Eva P S

    2015-01-01

    Crust at many divergent plate boundaries forms primarily by the injection of vertical sheet-like dykes, some tens of kilometres long. Previous models of rifting events indicate either lateral dyke growth away from a feeding source, with propagation rates decreasing as the dyke lengthens, or magma flowing vertically into dykes from an underlying source, with the role of topography on the evolution of lateral dykes not clear. Here we show how a recent segmented dyke intrusion in the Bárðarbunga volcanic system grew laterally for more than 45 kilometres at a variable rate, with topography influencing the direction of propagation. Barriers at the ends of each segment were overcome by the build-up of pressure in the dyke end; then a new segment formed and dyke lengthening temporarily peaked. The dyke evolution, which occurred primarily over 14 days, was revealed by propagating seismicity, ground deformation mapped by Global Positioning System (GPS), interferometric analysis of satellite radar images (InSAR), and graben formation. The strike of the dyke segments varies from an initially radial direction away from the Bárðarbunga caldera, towards alignment with that expected from regional stress at the distal end. A model minimizing the combined strain and gravitational potential energy explains the propagation path. Dyke opening and seismicity focused at the most distal segment at any given time, and were simultaneous with magma source deflation and slow collapse at the Bárðarbunga caldera, accompanied by a series of magnitude M > 5 earthquakes. Dyke growth was slowed down by an effusive fissure eruption near the end of the dyke. Lateral dyke growth with segment barrier breaking by pressure build-up in the dyke distal end explains how focused upwelling of magma under central volcanoes is effectively redistributed over long distances to create new upper crust at divergent plate boundaries. PMID:25517098

  7. Centralized Goal Formation and Systemic Reform

    Directory of Open Access Journals (Sweden)

    Kenneth A. Strike

    1997-04-01

    Full Text Available This paper asks whether there are reasonable concerns about liberty raised by standards driven systemic reform. Part I explores three kinds of concerns, students' interests in autonomy and authenticity, academic freedom, and pluralism. Part II explores two ways of conceptualizing the balance between liberty and various public interests, neo-classical economics and contemporary conservative thought. The paper draws two major conclusions about standards driven systemic reform: (1 This picture of reform raises serious questions about liberty. It may be inconsistent with some liberty interests of students. It is likely to pose serious questions about academic freedom and about pluralism. These concerns should make us cautious about systemic reform and should motivate us to a broader discussion of its assumptions and consequences. (2 The best defense of public sector reform efforts against their market oriented competition is one that emphasizes the importance of political goods such as citizenship. However, standards driven reform needs to avoid linkage with any nationalistic form of communitarianism. In order to do this it needs to seek ways to balance the demands for centralized goals and an educational system with an equal concern for local democracy, pluralism and community. A view of standards and accountability that is narrowly focused on clear public interests is crucial. The paper concludes with an argument that we need to focus attention on the question of what makes for good educational communities, a discussion that is not abetted by debating issues of reform in a framework that poses choices between public sector and market approaches.

  8. Alkanes and alkenes in Mediterranean volcanic-hydrothermal systems: origins and geothermometry

    Science.gov (United States)

    Fiebig, Jens; D'Alessandro, Walter; Tassi, Franco; Woodland, Alan

    2010-05-01

    It is still a matter of debate if nature provides conditions for abiogenic production of hydrocarbons. Methane (C1) and the C2+ alkanes emanating from ultramafic hydrothermal systems such as Lost City have been considered to be abiogenic in origin, mainly because of the occurrence of an isotopic reversal between methane and the C2+hydrocarbons and C1/C2+ ratios >1000 [1]. Abiogenic production of methane has been postulated to occur under the relatively oxidizing redox conditions of continental-hydrothermal systems, too. It was observed that temperatures received from the H2-H2O-CO-CO2-CH4 geoindicator were coincident with temperatures derived from carbon isotope partitioning between CO2 and CH4in gases released from the Mediterranean volcanic-hydrothermal systems of Nisyros (Greece), Vesuvio and Ischia (both Italy) [2]. Such equilibrium pattern, if not fortuitous, can only be obtained if mantle- and marine limestone-derived CO2 is reduced to CH4. At Nisyros, observed C1/C2+ ratios from 300-4000 are in agreement with an abiogenic origin of the methane. Ethane and propane, however, were shown to be non-genetic with CO2 and methane. C1/C2 and C2/C3 distribution ratios may point to the admixture of small amounts of hydrocarbons deriving from the thermal decomposition of organic matter along with abiogenically equilibrated methane essentially devoid of the higher hydrocarbons [3]. Here, we provide new isotopic and hydrocarbon concentration data on several Mediterranean volcanic-hydrothermal systems, including Nisyros, Vesuvio, Ischia, Vulcano, Solfatara and Pantelleria. Wherever possible, we have extended our data set for the hydrogen isotope composition of CH4 and H2, n-alkane- and alkene/alkane-distribution ratios. At Nisyros, measured alkene/alkane- and H2/H2O concentration ratios confirm the attainment of equilibrium between CO2 and CH4. CO2 and CH4 appear to have equilibrated in the liquid phase at temperatures of ~360° C and redox conditions closely corresponding

  9. The central nervous system of ascidian larvae.

    Science.gov (United States)

    Hudson, Clare

    2016-09-01

    Ascidians are marine invertebrate chordates. Their tadpole larvae contain a dorsal tubular nervous system, resulting from the rolling up of a neural plate. Along the anterior-posterior (A-P) axis, the central nervous system (CNS) is organized into a sensory vesicle, neck, trunk ganglion, and tail nerve cord and consists of approximately only 330 cells, of which around 100 are thought to be neurons. The organization of distinct neuronal cell types and neurotransmitter gene expression within the CNS has been described. The unique developmental mode of ascidians, with a small number of cells and a fixed cell division pattern, allows individual cells to be traced throughout development. This feature has led to the complete documentation of the cell lineages of certain cell types in the CNS. Thus, a step-by-step understanding of nervous system development from the initial stages of neural induction to the neurogenesis of individual neurons is a feasible goal. The genetic control of neural fate induction and early neural plate patterning are now well understood. The molecular mechanisms specifying the cholinergic neurons of the trunk ganglion as well as the pigment cells of the sensory organs are also well elucidated. In addition, studies have begun on the morphogenetic processes of neurulation. Remaining challenges include building an embryonic atlas integrating gene expression patterns, cell lineage, and neuronal cell types as well as developing the gene regulatory networks of cell fate specification and integrating them with the genetic control of morphogenesis. WIREs Dev Biol 2016, 5:538-561. doi: 10.1002/wdev.239 For further resources related to this article, please visit the WIREs website. PMID:27328318

  10. Systemic juvenile xanthogranuloma with multiple central nervous system lesions

    Directory of Open Access Journals (Sweden)

    Ali Meshkini

    2012-01-01

    Full Text Available Juvenile xanthogranulomatosis (JXG is an uncommon histiocytic disorder that is usually benign and limited to the skin. The systemic form of JXG is rare and may be associated with severe morbidity and mortality especially in central nervous system (CNS involvement. Here, we describe a six-year-old boy with disseminated skin lesions and neurological signs and symptoms. Diagnostic work up revealed multiple brain lesions. A skin biopsy and a stereotactic brain biopsy considered suggestive of systemic JXG. Treatment with prednisolone, vinblastine and methotrexate was successful with regression of skin and CNS lesions. The patient has been in remission for almost three years.

  11. Time perception mechanisms at central nervous system

    Directory of Open Access Journals (Sweden)

    Rhailana Fontes

    2016-04-01

    Full Text Available The five senses have specific ways to receive environmental information and lead to central nervous system. The perception of time is the sum of stimuli associated with cognitive processes and environmental changes. Thus, the perception of time requires a complex neural mechanism and may be changed by emotional state, level of attention, memory and diseases. Despite this knowledge, the neural mechanisms of time perception are not yet fully understood. The objective is to relate the mechanisms involved the neurofunctional aspects, theories, executive functions and pathologies that contribute the understanding of temporal perception. Articles form 1980 to 2015 were searched by using the key themes: neuroanatomy, neurophysiology, theories, time cells, memory, schizophrenia, depression, attention-deficit hyperactivity disorder and Parkinson’s disease combined with the term perception of time. We evaluated 158 articles within the inclusion criteria for the purpose of the study. We conclude that research about the holdings of the frontal cortex, parietal, basal ganglia, cerebellum and hippocampus have provided advances in the understanding of the regions related to the perception of time. In neurological and psychiatric disorders, the understanding of time depends on the severity of the diseases and the type of tasks.

  12. Geodetic observations and modeling of magmatic inflation at the Three Sisters volcanic center, central Oregon Cascade Range, USA

    Science.gov (United States)

    Dzurisin, Daniel; Lisowski, Michael; Wicks, Charles W.; Poland, Michael P.; Endo, Elliot T.

    2006-01-01

    Tumescence at the Three Sisters volcanic center began sometime between summer 1996 and summer 1998 and was discovered in April 2001 using interferometric synthetic aperture radar (InSAR). Swelling is centered about 5 km west of the summit of South Sister, a composite basaltic-andesite to rhyolite volcano that last erupted between 2200 and 2000 yr ago, and it affects an area ∼20 km in diameter within the Three Sisters Wilderness. Yearly InSAR observations show that the average maximum displacement rate was 3–5 cm/yr through summer 2001, and the velocity of a continuous GPS station within the deforming area was essentially constant from June 2001 to June 2004. The background level of seismic activity has been low, suggesting that temperatures in the source region are high enough or the strain rate has been low enough to favor plastic deformation over brittle failure. A swarm of about 300 small earthquakes (Mmax = 1.9) in the northeast quadrant of the deforming area on March 23–26, 2004, was the first notable seismicity in the area for at least two decades. The U.S. Geological Survey (USGS) established tilt-leveling and EDM networks at South Sister in 1985–1986, resurveyed them in 2001, the latter with GPS, and extended them to cover more of the deforming area. The 2001 tilt-leveling results are consistent with the inference drawn from InSAR that the current deformation episode did not start before 1996, i.e., the amount of deformation during 1995–2001 from InSAR fully accounts for the net tilt at South Sister during 1985–2001 from tilt-leveling. Subsequent InSAR, GPS, and leveling observations constrain the source location, geometry, and inflation rate as a function of time. A best-fit source model derived from simultaneous inversion of all three datasets is a dipping sill located 6.5 ± 2.5 km below the surface with a volume increase of 5.0 × 106 ± 1.5 × 106m3/yr (95% confidence limits). The most likely cause of tumescence is a pulse of

  13. Deep seismic sounding investigation into the deep structure of the magma system in Changbaishan-Tianchi volcanic region

    Institute of Scientific and Technical Information of China (English)

    张先康; 张成科; 赵金仁; 杨卓欣; 李松林; 张建狮; 刘宝峰; 成双喜; 孙国伟; 潘素珍

    2002-01-01

    The magma system of Changbaishan-Tianchi Volcanic region is studied with three-dimensional deep seismic sounding (DSS) technique. The results show that the magma system of Changbaishan-Tianchi volcanic region, mainly characterized by low velocity of P wave, can be divided into three parts in terms of depth. At the depth range of 9(15 km, the distribution of the magma system is characterized by extensiveness, large scale and near-SN orientation. This layer is the major place for magma storage. From the depth of 15 km down to the lower crust, it is characterized by small lateral scale, which indicates the (trace( of magma intrusion from the upper mantle into the crust and also implies that the magma system most probably extends to the upper mantle, or even deeper.(less than 8(9 km deep), the range of magma distribution is even smaller, centering on an SN-oriented area just north of the Tianchi crater. If low velocity of P wave is related to the magma system, it then reflects that the magma here is still in a state of relatively high temperature. In this sense, the magma system of Changbaishan-Tianchi volcanic region is at least not (remains(, in other words, it is in an (active( state.

  14. Conceptual design for the NSTX Central Instrumentation and Control System

    International Nuclear Information System (INIS)

    The design and construction phase for the National Spherical Torus Experiment (NSTX) is under way at the Princeton Plasma Physics Laboratory (PPPL). Operation is scheduled to begin on April 30, 1999. This paper describes the conceptual design for the NSTX Central Instrumentation and Control (I and C) System. Major elements of the Central I and C System include the Process Control System, Plasma Control System, Network System, Data Acquisition System, and Synchronization System to support the NSTX experimental device

  15. The influence of cooling, crystallisation and re-melting on the interpretation of geodetic signals in volcanic systems

    Science.gov (United States)

    Caricchi, Luca; Biggs, Juliet; Annen, Catherine; Ebmeier, Susanna

    2014-02-01

    Deformation of volcanic edifices is typically attributed to the movement of magma within the volcanic plumbing system, but a wide range of magmatic processes are capable of producing significant volume variations and may also produce deformation. In order to understand the evolution of magmatic systems prior to eruption and correctly interpret monitoring signals, it is necessary to quantify the patterns and timescales of surface deformation that processes such as crystallisation, degassing and expansion of the hydrothermal system can produce. We show how the combination of petrology and thermal modelling can be applied to geodetic observations to identify the processes occurring in a magmatic reservoir during volcanic unrest. Thermal modelling and petrology were used to determine the timescales and volumetric variations associated with cooling, crystallisation and gas exsolution. These calculations can be performed rapidly and highlight the most likely processes responsible for the variation of a set of monitoring parameters. We then consider the magnitude and timescales of deformation produced by other processes occurring within the vicinity of an active magma system. We apply these models to a time series of geodetic data spanning the period between the 1997 and 2008 eruptions of Okmok volcano, Aleutians, examining scenarios involving crystallisation, degassing and remelting of the crystallising shallow magmatic body and including a viscoelastic shell or hydrothermal system. The geodetic observations are consistent with the injection of a water-saturated basalt, followed by minor crystallisation and degassing. Other scenarios are not compatible either with the magnitude or rate of the deformation signals.

  16. Miniaturized Airborne Imaging Central Server System

    Science.gov (United States)

    Sun, Xiuhong

    2011-01-01

    In recent years, some remote-sensing applications require advanced airborne multi-sensor systems to provide high performance reflective and emissive spectral imaging measurement rapidly over large areas. The key or unique problem of characteristics is associated with a black box back-end system that operates a suite of cutting-edge imaging sensors to collect simultaneously the high throughput reflective and emissive spectral imaging data with precision georeference. This back-end system needs to be portable, easy-to-use, and reliable with advanced onboard processing. The innovation of the black box backend is a miniaturized airborne imaging central server system (MAICSS). MAICSS integrates a complex embedded system of systems with dedicated power and signal electronic circuits inside to serve a suite of configurable cutting-edge electro- optical (EO), long-wave infrared (LWIR), and medium-wave infrared (MWIR) cameras, a hyperspectral imaging scanner, and a GPS and inertial measurement unit (IMU) for atmospheric and surface remote sensing. Its compatible sensor packages include NASA s 1,024 1,024 pixel LWIR quantum well infrared photodetector (QWIP) imager; a 60.5 megapixel BuckEye EO camera; and a fast (e.g. 200+ scanlines/s) and wide swath-width (e.g., 1,920+ pixels) CCD/InGaAs imager-based visible/near infrared reflectance (VNIR) and shortwave infrared (SWIR) imaging spectrometer. MAICSS records continuous precision georeferenced and time-tagged multisensor throughputs to mass storage devices at a high aggregate rate, typically 60 MB/s for its LWIR/EO payload. MAICSS is a complete stand-alone imaging server instrument with an easy-to-use software package for either autonomous data collection or interactive airborne operation. Advanced multisensor data acquisition and onboard processing software features have been implemented for MAICSS. With the onboard processing for real time image development, correction, histogram-equalization, compression, georeference, and

  17. Central nervous system manifestations of neonatal lupus: a systematic review.

    Science.gov (United States)

    Chen, C C; Lin, K-L; Chen, C-L; Wong, A May-Kuen; Huang, J-L

    2013-12-01

    Neonatal lupus is a rare and acquired autoimmune disease. Central nervous system abnormalities are potential manifestations in neonatal lupus. Through a systematic literature review, we analyzed the clinical features of previously reported neonatal lupus cases where central nervous system abnormalities had been identified. Most reported neonatal lupus patients with central nervous system involvement were neuroimaging-determined and asymptomatic. Only seven neonatal lupus cases were identified as having a symptomatic central nervous system abnormality which caused physical disability or required neurosurgery. A high percentage of these neurosymptomatic neonatal lupus patients had experienced a transient cutaneous skin rash and had no maternal history of autoimmune disease before pregnancy.

  18. U-Pb SHRIMP and Sm-Nd geochronology of the Silvania Volcanics and Jurubatuba Granite: juvenile paleoproterozoic crust in the basement of the Neo proterozoic Brasilia Belt, Goias, central Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fischel, Danielle P.; Pimentel, Marcio M.; Fuck, Reinhardt A. [Brasilia Univ., DF (Brazil). Inst. de Geociencias; Armstrong, Richard [Australian National Univ., Canberra (Australia). Research School of Earth Sciences

    2001-09-15

    U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic meta volcanic rocks from the Silvania Sequence and Jurubatuba Granite in the central part of the Brasilia Belt. Zircon grains from a meta volcanic sample yielded 2115 {+-} 23 Ma and from the granite yielded 2089 {+-}14 Ma, interpreted as crystallization ages of these rocks. Six meta volcanic samples of the Silvania Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 {+-}110 Ma and positive {epsilon}{sub Nd} (T) = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T{sub DM} model ages between 2.30 and 2.42 Ga and {epsilon}{sub Nd} (T) values vary between -0.22 and -0.58. The oldest T{sub DM} value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvania volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasilia Belt that implies the presence of arc/suture hidden in reworked basement of the Brasilia Belt. (author)

  19. Congenital tumors of the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Severino, Mariasavina [G. Gaslini Children' s Hospital, Department of Neuroradiology, Genoa (Italy); Schwartz, Erin S. [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Thurnher, Majda M. [Medical University of Vienna, Department of Radiology, Vienna (Austria); Rydland, Jana [MR Center, St. Olav' s Hospital HF, Trondheim (Norway); Nikas, Ioannis [Agia Sophia Children' s Hospital, Imaging Department, Athens (Greece); Rossi, Andrea [G. Gaslini Children' s Hospital, Department of Neuroradiology, Genoa (Italy); G. Gaslini Children' s Hospital, Department of Pediatric Neuroradiology, Genoa (Italy)

    2010-06-15

    Congenital tumors of the central nervous system (CNS) are often arbitrarily divided into ''definitely congenital'' (present or producing symptoms at birth), ''probably congenital'' (present or producing symptoms within the first week of life), and ''possibly congenital'' (present or producing symptoms within the first 6 months of life). They represent less than 2% of all childhood brain tumors. The clinical features of newborns include an enlarged head circumference, associated hydrocephalus, and asymmetric skull growth. At birth, a large head or a tense fontanel is the presenting sign in up to 85% of patients. Neurological symptoms as initial symptoms are comparatively rare. The prenatal diagnosis of congenital CNS tumors, while based on ultrasonography, has significantly benefited from the introduction of prenatal magnetic resonance imaging studies. Teratomas constitute about one third to one half of these tumors and are the most common neonatal brain tumor. They are often immature because of primitive neural elements and, rarely, a component of mixed malignant germ cell tumors. Other tumors include astrocytomas, choroid plexus papilloma, primitive neuroectodermal tumors, atypical teratoid/rhabdoid tumors, and medulloblastomas. Less common histologies include craniopharyngiomas and ependymomas. There is a strong predilection for supratentorial locations, different from tumors of infants and children. Differential diagnoses include spontaneous intracranial hemorrhage that can occur in the presence of coagulation factor deficiency or underlying vascular malformations, and congenital brain malformations, especially giant heterotopia. The prognosis for patients with congenital tumors is generally poor, usually because of the massive size of the tumor. However, tumors can be resected successfully if they are small and favorably located. The most favorable outcomes are achieved with choroid plexus tumors

  20. Volcanic sanidinites: an example for the mobilization of high field strength elements (HFSE) in magmatic systems

    Science.gov (United States)

    Aßbichler, Donjá; Heuss-Aßbichler, Soraya; Müller, Dirk; Kunzmann, Thomas

    2016-04-01

    In earth science the mobility of high field strength elements (HFSE) is generally discussed in context of hydrothermal processes. Recent investigations mainly address processes in (late) magmatic-, metamorphic- and submarine hydrothermal systems. They have all in common that H2O is main solvent. The transport of HFSE is suggested to be favored by volatiles, like boron, fluorine, phosphate and sulfate (Jiang et al., 2005). In this study processes in magmatic system are investigated. Sanidinites are rare rocks of igneous origin and are found as volcanic ejecta of explosive volcanoes. They consist mainly of sanidine and minerals of the sodalite group. The very porous fabric of these rocks is an indication of their aggregation from a gaseous magmatic phase. The large sanidine crystals (up to several centimeters) are mostly interlocking, creating large cavities between some crystals. In these pores Zr crystallizes as oxide (baddeleyite, ZrO2) or silicate (zircon, ZrSiO4). The euhedral shape of these minerals is a further indication of their formation out of the gas phase. Furthermore, bubbles in glass observed in some samples are evidence for gas-rich reaction conditions during the formation of the sanidinites. The formation of sanidinites is suggested to be an example for solvothermal processes in natural systems. Solvothermal processes imply the solvation, transport and recrystallization of elements in a gas phase. Results obtained from whole rock analysis from sanidinites from Laacher See (Germany) show a positive correlation between LOI, sulfate, Cl, and Na with the HFSE like Zr. Na-rich conditions seem to ameliorate the solvothermal transport of Zr. All these features point to the formation of sanidinites in the upper part of a magma chamber, where fluid consisting of SO3 and Cl compounds in addition to H2O, CO2 and HFSE (high field strength elements) like Zr accumulate.

  1. Tephra layers from Holocene lake sediments of the Sulmona Basin, central Italy: implications for volcanic activity in Peninsular Italy and tephrostratigraphy in the central Mediterranean area

    Science.gov (United States)

    Giaccio, B.; Messina, P.; Sposato, A.; Voltaggio, M.; Zanchetta, G.; Galadini, F.; Gori, S.; Santacroce, R.

    2009-12-01

    We present a new tephrostratigraphic record from the Holocene lake sediments of the Sulmona basin, central Italy. The Holocene succession is represented by whitish calcareous mud that is divided into two units, SUL2 (ca 32 m thick) and SUL1 (ca 8 m thick), for a total thickness of ca 40 m. These units correspond to the youngest two out of six sedimentary cycles recognised in the Sulmona basin that are related to the lake sedimentation since the Middle Pleistocene. Height concordant U series age determinations and additional chronological data constrain the whole Holocene succession to between ca 8000 and 1000 yrs BP. This includes a sedimentary hiatus that separates the SUL2 and SUL1 units, which is roughly dated between Ischia Island eruption of the Cannavale tephra (2920 ± 450 cal yrs BP). The 27 ash layers compatible with Mt. Somma-Vesuvius activity are clustered in three different time intervals: from ca 2000 to >1000; from 3600 to 3100; and from 7600 to 4700 yrs BP. The first, youngest cluster, comprises six layers and correlates with the intense explosive activity of Mt. Somma-Vesuvius that occurred after the prominent AD 79 Pompeii eruption, but only the near-Plinian event of AD 472 has been tentatively recognised. The intermediate cluster (3600-3100 yrs BP) starts with tephra that chemically and chronologically matches the products from the "Pomici di Avellino" eruption (ca 3800 ± 200 yrs BP). This is followed by eight further layers, where the glasses exhibit chemical features that are similar in composition to the products from the so-called "Protohistoric" or AP eruptions; however, only the distal equivalents of three AP events (AP3, AP4 and AP6) are tentatively designated. Finally, the early cluster (7600-4700 yrs BP) comprises 12 layers that contain evidence of a surprising, previously unrecognised, activity of the Mt. Somma-Vesuvius volcano during its supposed period of quiescence, between the major Plinian "Pomici di Mercato" (ca 9000 yrs BP) and

  2. Relative contributions of crust and mantle to the origin of the Bijli Rhyolite in a palaeoproterozoic bimodal volcanic sequence (Dongargarh Group), central India

    Indian Academy of Sciences (India)

    Sarajit Sensarma; S Hoernes; Dhruba Mukhopadhyay

    2004-12-01

    New mineralogical, bulk chemical and oxygen isotope data on the Palaeoproterozoic Bijli Rhyolite, the basal unit of a bimodal volcanic sequence (Dongargarh Group) in central India, and one of the most voluminous silicic volcanic expressions in the Indian Shield, are presented. The Bijli Rhyolite can be recognized as a poorly sorted pyroclastic deposit, and comprises of phenocrystic K-feldspar + albite ± anorthoclase set in fine-grained micro-fragmental matrix of quartz-feldsparsericite- chlorite-iron-oxide ± calcite. The rocks are largely metaluminous with high SiO2, Na2O+ KO, Fe/Mg, Ga/Al, Zr, Ta, Sn, Y, REE and low CaO, Ba, Sr contents; the composition points to an ‘A-type granite’ melt. The rocks show negative Cs-, Sr-, Eu- and Ti- anomalies with incompatible element concentrations 2–3 times more than the upper continental crust (UCC). LREE is high (La/Yb ∼20) and HREE 20-30 times chondritic. 18 Owhole-rock varies between 4.4 and 7.8‰(mean 5.87 ± 1.26‰). The Bijli melt is neither formed by fractionation of a basaltic magma, nor does it represent a fractionated crustal melt. It is shown that the mantle-derived high temperature basaltic komatiitic melts/high Mg basalts triggered crustal melting, and interacted predominantly with deep crust compositionally similar to the Average Archaean Granulite (AAG), and a shallower crustal component with low CaO and Al2O3 to give rise to the hybrid Bijli melts. Geochemical mass balance suggests that ∼30% partial melting of AAG under anhydrous condition, instead of the upper continental crust (UCC) including the Amgaon granitoid gneiss reported from the area, better matches the trace element concentrations in the rocks. The similar Ta/Th of the rhyolites (0.060) and average granulite (0.065) vs. UCC (0.13) also support a deep crustal protolith. Variable contributions of crust and mantle, and action of hydrothermal fluid are attributed for the spread in 18Owhole-rock values. The fast eruption of high

  3. Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) project and a next-generation real-time volcano hazard assessment system

    Science.gov (United States)

    Takarada, S.

    2012-12-01

    The first Workshop of Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER1) was held in Tsukuba, Ibaraki Prefecture, Japan from February 23 to 24, 2012. The workshop focused on the formulation of strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis, and volcanic eruptions. More than 150 participants attended the workshop. During the workshop, the G-EVER1 accord was approved by the participants. The Accord consists of 10 recommendations like enhancing collaboration, sharing of resources, and making information about the risks of earthquakes and volcanic eruptions freely available and understandable. The G-EVER Hub website (http://g-ever.org) was established to promote the exchange of information and knowledge among the Asia-Pacific countries. Several G-EVER Working Groups and Task Forces were proposed. One of the working groups was tasked to make the next-generation real-time volcano hazard assessment system. The next-generation volcano hazard assessment system is useful for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is planned to be developed based on volcanic eruption scenario datasets, volcanic eruption database, and numerical simulations. Defining volcanic eruption scenarios based on precursor phenomena leading up to major eruptions of active volcanoes is quite important for the future prediction of volcanic eruptions. Compiling volcanic eruption scenarios after a major eruption is also important. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and styles, is important for the next-generation volcano hazard assessment system. The volcanic eruption database is developed based on past eruption results, which only represent a subset of possible future scenarios. Hence, different distributions from the previous deposits are mainly observed due to the differences in

  4. First Steps Towards the Paleoseismological History of the Pastores and Venta de Bravo Faults, Acambay Graben, Trans-Mexican Volcanic Belt, Central Mexico

    Science.gov (United States)

    Persaud, M.; Zúñiga, F. R.; Aguirre-Díaz, G.; Villamor, P.; Langridge, R.

    2006-12-01

    The Acambay graben is part of the Trans-Mexican Volcanic Belt (TMVB) which strikes ESE-WNW across central Mexico. The belt is an active, calc-alkaline volcanic arc that is related to the subduction of the Rivera and Cocos plates underneath the North American plate (e.g. Suter et al. 1995). The TMVB comprises a series of intra-arc basins that form the Chapala-Tula fault zone (450 km long, 50 km wide, Suter et al. 1995). The Acambay graben is c. 80 km long, 15 to 35 km wide and limited by four large E-W striking normal faults that are from west to east, the Epitacio-Huerta (EHF) and the Acambay-Tixmadejé faults (ATF) in the north and the Venta de Bravo (VBF) and the Pastores faults (PF) in the south. In the region, there is a low current seismicity but two known historic earthquakes occurred in the graben, the November 19, 1912, ms = 7.0 Acambay event and the February 22, 1979, ms = 4.9 Maravatío earthquake (Astíz-Delgado 1980). The paleoseismic history of the ATF has been previously studied by Langridge et al. (2000). Our focus lies on the paleoseismicity of the southern faults. The rupture history is assessed by tectonic geomorphology and paleoseismic trenches. To study the recent paleoseismic history of the two southern faults, we excavated two trenches on the PF. These trenches lie on young alluvial fans protruding from the Pastores fault scarp. Their location was chosen because of ' steps'\\ in the surface of the alluvial fan that might indicate the position of the most recent fault scarps, in combination with georadar profiles that confirmed vertical displacements in reflectors underneath those steps. The strata in the trenches consist of lake sediments at the base of one trench overlain by interbedded volcanic pyroclastic flows and ash falls which are found in both trenches. In both trenches we found evidence for one paleoearthquake respectively. We are in the process of dating these events by means abundant charcoal which we found in the pyroclastic

  5. Three thousand years of flank and central vent eruptions of the San Salvador volcanic complex (El Salvador) and their effects on El Cambio archeological site: a review based on tephrostratigraphy

    Science.gov (United States)

    Ferrés, D.; Delgado Granados, H.; Hernández, W.; Pullinger, C.; Chávez, H.; Castillo Taracena, C. R.; Cañas-Dinarte, C.

    2011-09-01

    The volcanic events of the last 3,000 years at San Salvador volcanic complex are reviewed using detailed stratigraphic records exposed in new excavations between 2005 and 2007, at El Cambio archeological site (Zapotitán Valley, El Salvador), and in other outcrops on the northern and northwestern sectors of the complex. The sequences that overlie Tierra Blanca Joven (cal. 429 ± 107 ad), from the Ilopango caldera, comprise the Loma Caldera (cal. 590 ± 90 ad) and El Playón (1658-1671) deposits and the San Andrés Tuff (cal. 1031 ± 29 ad), related to El Boquerón Volcano. The surge deposits within the El Playón, San Andrés Tuff and overlying Talpetate II sequences indicate the significance of phreatomagmatic phases in both central vent and flank eruptions during the last 1,600 years. Newly identified volcanic deposits underlying Tierra Blanca Joven at El Cambio extend the stratigraphic record of the area to 3,000 years bp. Paleosols interstratified with those deposits contain cultural artifacts which could be associated with the Middle Preclassic period (900-400 bc). If correct, human occupation of the site during the Preclassic period was more intense than previously known and volcanic eruptions must have affected prehistoric settlements. The archeological findings provide information on how prehistoric populations dealt with volcanic hazards, thousands of years ago in the eastern Zapotitán Valley, where several housing projects are currently being developed. The new stratigraphic and volcanological data can be used as a basis for local and regional hazard assessment related to future secondary vent activity in the San Salvador Volcanic Complex.

  6. High-latitude volcanic eruptions in the Norwegian Earth System Model: the effect of different initial conditions and of the ensemble size

    Directory of Open Access Journals (Sweden)

    Francesco S. R. Pausata

    2015-06-01

    Full Text Available Large volcanic eruptions have strong impacts on both atmospheric and ocean dynamics that can last for decades. Numerical models have attempted to reproduce the effects of major volcanic eruptions on climate; however, there are remarkable inter-model disagreements related to both short-term dynamical response to volcanic forcing and long-term oceanic evolution. The lack of robust simulated behaviour is related to various aspects from model formulation to simulated background internal variability to the eruption details. Here, we use the Norwegian Earth System Model version 1 to calculate interactively the volcanic aerosol loading resulting from SO2 emissions of the second largest high-latitude volcanic eruption in historical time (the Laki eruption of 1783. We use two different approaches commonly used interchangeably in the literature to generate ensembles. The ensembles start from different background initial states, and we show that the two approaches are not identical on short-time scales (<1 yr in discerning the volcanic effects on climate, depending on the background initial state in which the simulated eruption occurred. Our results also show that volcanic eruptions alter surface climate variability (in general increasing it when aerosols are allowed to realistically interact with circulation: Simulations with fixed volcanic aerosol show no significant change in surface climate variability. Our simulations also highlight that the change in climate variability is not a linear function of the amount of the volcanic aerosol injected. We then provide a tentative estimation of the ensemble size needed to discern a given volcanic signal on surface temperature from the natural internal variability on regional scale: At least 20–25 members are necessary to significantly detect seasonally averaged anomalies of 0.5°C; however, when focusing on North America and in winter, a higher number of ensemble members (35–40 is necessary.

  7. Groundwater flow processes and mixing in active volcanic systems: the case of Guadalajara (Mexico)

    Science.gov (United States)

    Hernández-Antonio, A.; Mahlknecht, J.; Tamez-Meléndez, C.; Ramos-Leal, J.; Ramírez-Orozco, A.; Parra, R.; Ornelas-Soto, N.; Eastoe, C. J.

    2015-09-01

    other active volcanic systems on Earth.

  8. Geochemistry of the late Holocene rocks from the Tolbachik volcanic field, Kamchatka: Quantitative modelling of subduction-related open magmatic systems

    Science.gov (United States)

    Portnyagin, Maxim; Duggen, Svend; Hauff, Folkmar; Mironov, Nikita; Bindeman, Ilya; Thirlwall, Matthew; Hoernle, Kaj

    2015-12-01

    We present new major and trace element, high-precision Sr-Nd-Pb (double spike), and O-isotope data for the whole range of rocks from the Holocene Tolbachik volcanic field in the Central Kamchatka Depression (CKD). The Tolbachik rocks range from high-Mg basalts to low-Mg basaltic trachyandesites. The rocks considered in this paper represent mostly Late Holocene eruptions (using tephrochronological dating), including historic ones in 1941, 1975-1976 and 2012-2013. Major compositional features of the Tolbachik volcanic rocks include the prolonged predominance of one erupted magma type, close association of middle-K primitive and high-K evolved rocks, large variations in incompatible element abundances and ratios but narrow range in isotopic composition. We quantify the conditions of the Tolbachik magma origin and evolution and revise previously proposed models. We conclude that all Tolbachik rocks are genetically related by crystal fractionation of medium-K primary magmas with only a small range in trace element and isotope composition. The primary Tolbachik magmas contain ~ 14 wt.% of MgO and ~ 4% wt.% of H2O and originated by partial melting (~ 6%) of moderately depleted mantle peridotite with Indian-MORB-type isotopic composition at temperature of ~ 1250 °C and pressure of ~ 2 GPa. The melting of the mantle wedge was triggered by slab-derived hydrous melts formed at ~ 2.8 GPa and ~ 725 °C from a mixture of sediments and MORB- and Meiji-type altered oceanic crust. The primary magmas experienced a complex open-system evolution termed Recharge-Evacuation-Fractional Crystallization (REFC). First the original primary magmas underwent open-system crystal fractionation combined with periodic recharge of the magma chamber with more primitive magma, followed by mixing of both magma types, further fractionation and finally eruption. Evolved high-K basalts, which predominate in the Tolbachik field, and basaltic trachyandesites erupted in 2012-2013 approach steady-state REFC

  9. Development of a portable active long-path differential optical absorption spectroscopy system for volcanic gas measurements

    Science.gov (United States)

    Vita, Fabio; Kern, Christoph; Inguaggiato, Salvatore

    2014-01-01

    Active long-path differential optical absorption spectroscopy (LP-DOAS) has been an effective tool for measuring atmospheric trace gases for several decades. However, instruments were large, heavy and power-inefficient, making their application to remote environments extremely challenging. Recent developments in fibre-coupling telescope technology and the availability of ultraviolet light emitting diodes (UV-LEDS) have now allowed us to design and construct a lightweight, portable, low-power LP-DOAS instrument for use at remote locations and specifically for measuring degassing from active volcanic systems. The LP-DOAS was used to measure sulfur dioxide (SO2) emissions from La Fossa crater, Vulcano, Italy, where column densities of up to 1.2 × 1018 molec cm−2 (~ 500 ppmm) were detected along open paths of up to 400 m in total length. The instrument's SO2 detection limit was determined to be 2 × 1016 molec cm−2 (~ 8 ppmm), thereby making quantitative detection of even trace amounts of SO2 possible. The instrument is capable of measuring other volcanic volatile species as well. Though the spectral evaluation of the recorded data showed that chlorine monoxide (ClO) and carbon disulfide (CS2) were both below the instrument's detection limits during the experiment, the upper limits for the X / SO2 ratio (X = ClO, CS2) could be derived, and yielded 2 × 10−3 and 0.1, respectively. The robust design and versatility of the instrument make it a promising tool for monitoring of volcanic degassing and understanding processes in a range of volcanic systems.

  10. Bromo volcano area as human-environment system: interaction of volcanic eruption, local knowledge, risk perception and adaptation strategy

    Science.gov (United States)

    Bachri, Syamsul; Stötter, Johann; Sartohadi, Junun

    2013-04-01

    People in the Bromo area (located within Tengger Caldera) have learn to live with the threat of volcanic hazard since this volcano is categorized as an active volcano in Indonesia. During 2010, the eruption intensity increased yielding heavy ash fall and glowing rock fragments. A significant risk is also presented by mass movement which reaches areas up to 25 km from the crater. As a result of the 2010 eruption, 12 houses were destroyed, 25 houses collapsed and there were severe also effects on agriculture and the livestock sector. This paper focuses on understanding the interaction of Bromo volcanic eruption processes and their social responses. The specific aims are to 1) identify the 2010 eruption of Bromo 2) examine the human-volcano relationship within Bromo area in general, and 3) investigate the local knowledge related to hazard, risk perception and their adaptation strategies in specific. In-depth interviews with 33 informants from four districts nearest to the crater included local people and authorities were carried out. The survey focused on farmers, key persons (dukun), students and teachers in order to understand how people respond to Bromo eruption. The results show that the eruption in 2010 was unusual as it took continued for nine months, the longest period in Bromo history. The type of eruption was phreatomagmatic producing material dominated by ash to fine sand. This kind of sediment typically belongs to Tengger mountain eruptions which had produced vast explosions in the past. Furthermore, two years after the eruption, the interviewed people explained that local knowledge and their experiences with volcanic activity do not influence their risk perception. Dealing with this eruption, people in the Bromo area applied 'lumbung desa' (traditional saving systems) and mutual aid activity for surviving the volcanic eruption. Keywords: Human-environment system, local knowledge, risk perception, adaptation strategies, Bromo Volcano Indonesia

  11. Testing a model-driven Geographical Information System for risk assessment during an effusive volcanic crisis

    Science.gov (United States)

    Harris, Andrew; Latutrie, Benjamin; Andredakis, Ioannis; De Groeve, Tom; Langlois, Eric; van Wyk de Vries, Benjamin; Del Negro, Ciro; Favalli, Massimiliano; Fujita, Eisuke; Kelfoun, Karim; Rongo, Rocco

    2016-04-01

    RED-SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modeling and response communities with experience in tracking volcanic effusive events. It is an informal working group that has evolved around the philosophy of combining global scientific resources, in the realm of physical volcanology, remote sensing and modeling, to better define and limit uncertainty. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 2013. The main recommendation of the workshop in terms of modeling was that there is a pressing need for "real-time input of reliable Time-Averaged Discharge Rate (TADR) data with regular up-dates of Digital Elevation Models (DEMs) if modeling is to be effective; the DEMs can be provided by the radar/photogrammetry community." We thus set up a test to explore (i) which model source terms are needed, (ii) how they can be provided and updated, and (iii) how can models be run and applied in an ensemble approach. The test used two hypothetical effusive events in the Chaîne des Puys (Auvergne, France), for which a prototype Geographical Information System (GIS) was set up to allow loss assessment during an effusive crisis. This system drew on all immediately available data for population, land use, communications, utility and building-type. After defining lava flow model source terms (vent location, effusion rate, lava chemistry, temperature, crystallinity and vesicularity), five operational lava flow emplacement models were run (DOWNFLOW, FLOWGO, LAVASIM, MAGFLOW and VOLCFLOW) to produce a projection for likelihood of impact for all pixels within the area covered by the GIS, based on agreement between models. The test thus aimed not to assess the model output, but instead to examine overlapping output. Next, inundation maps and damage reports for impacted zones were produced. The exercise identified several

  12. Central nervous system adaptation to exercise training

    Science.gov (United States)

    Kaminski, Lois Anne

    Exercise training causes physiological changes in skeletal muscle that results in enhanced performance in humans and animals. Despite numerous studies on exercise effects on skeletal muscle, relatively little is known about adaptive changes in the central nervous system. This study investigated whether spinal pathways that mediate locomotor activity undergo functional adaptation after 28 days of exercise training. Ventral horn spinal cord expression of calcitonin gene-related peptide (CGRP), a trophic factor at the neuromuscular junction, choline acetyltransferase (Chat), the synthetic enzyme for acetylcholine, vesicular acetylcholine transporter (Vacht), a transporter of ACh into synaptic vesicles and calcineurin (CaN), a protein phosphatase that phosphorylates ion channels and exocytosis machinery were measured to determine if changes in expression occurred in response to physical activity. Expression of these proteins was determined by western blot and immunohistochemistry (IHC). Comparisons between sedentary controls and animals that underwent either endurance training or resistance training were made. Control rats received no exercise other than normal cage activity. Endurance-trained rats were exercised 6 days/wk at 31m/min on a treadmill (8% incline) for 100 minutes. Resistance-trained rats supported their weight plus an additional load (70--80% body weight) on a 60° incline (3 x 3 min, 5 days/wk). CGRP expression was measured by radioimmunoassay (RIA). CGRP expression in the spinal dorsal and ventral horn of exercise-trained animals was not significantly different than controls. Chat expression measured by Western blot and IHC was not significantly different between runners and controls but expression in resistance-trained animals assayed by IHC was significantly less than controls and runners. Vacht and CaN immunoreactivity in motor neurons of endurance-trained rats was significantly elevated relative to control and resistance-trained animals. Ventral

  13. On the behavior of site effects in central Mexico (the Mexican volcanic belt – MVB), based on records of shallow earthquakes that occurred in the zone between 1998 and 2011

    OpenAIRE

    Clemente-Chavez, A.; Zúñiga, F. R.; Lermo, J.; A. Figueroa-Soto; Valdés, C.; M. Montiel; O. Chavez; Arroyo, M.

    2014-01-01

    The Mexican volcanic belt (MVB) is a seismogenic zone that transects the central part of Mexico with an east–west orientation. The seismic risk and hazard of this seismogenic zone has not been studied in detail due to the scarcity of instrumental data as well as because seismicity in the continental regime of central Mexico is not too frequent. However, it is known that there are precedents of large earthquakes (Mw > 6.0) that have taken place in this zone. The valley of Mex...

  14. Statin therapy inhibits remyelination in the central nervous system

    DEFF Research Database (Denmark)

    Miron, Veronique E; Zehntner, Simone P; Kuhlmann, Tanja;

    2009-01-01

    Remyelination of lesions in the central nervous system contributes to neural repair following clinical relapses in multiple sclerosis. Remyelination is initiated by recruitment and differentiation of oligodendrocyte progenitor cells (OPCs) into myelinating oligodendrocytes. Simvastatin, a blood...... that OPCs were maintained in an immature state (Olig2(strong)/Nkx2.2(weak)). NogoA+ oligodendrocyte numbers were decreased during all simvastatin treatment regimens. Our findings suggest that simvastatin inhibits central nervous system remyelination by blocking progenitor differentiation, indicating...... the need to monitor effects of systemic immunotherapies that can access the central nervous system on brain tissue-repair processes....

  15. Calibration method for a central catadioptric-perspective camera system.

    Science.gov (United States)

    He, Bingwei; Chen, Zhipeng; Li, Youfu

    2012-11-01

    A central catadioptric-perspective camera system is widely used nowadays. A critical problem is that current calibration methods cannot determine the extrinsic parameters between the central catadioptric camera and a perspective camera effectively. We present a novel calibration method for a central catadioptric-perspective camera system, in which the central catadioptric camera has a hyperbolic mirror. Two cameras are used to capture images of one calibration pattern at different spatial positions. A virtual camera is constructed at the origin of the central catadioptric camera and faced toward the calibration pattern. The transformation between the virtual camera and the calibration pattern could be computed first and the extrinsic parameters between the central catadioptric camera and the calibration pattern could be obtained. Three-dimensional reconstruction results of the calibration pattern show a high accuracy and validate the feasibility of our method.

  16. Provenance and drainage system of the Early Cretaceous volcanic detritus in the Himalaya as constrained by detrital zircon geochronology

    Institute of Scientific and Technical Information of China (English)

    Xiu-Mian Hu; Eduardo Garzanti; Wei An

    2015-01-01

    The age range of the major intra-plate volcanic event that affected the northern Indian margin in the Early Cretaceous is here deifned precisely by detrital zircon geochronol-ogy. U–Pb ages of Early Cretaceous detrital zircons found in the Cretaceous to the Paleocene sandstones cluster mainly between 142 Ma and 123 Ma in the northern Tethys Himalayan unit, and between 140 Ma and 116 Ma in the southern Tethys Himalayan unit. The youngest and oldest detrital zircons within this group indicate that volcanism in the source areas started in the latest Jurassic and ended by the early Albian. Stratigraphic data indicate that volcaniclastic sedimentation began signiifcantly earlier in southern Tibet (Tithonian) than in Nepal (Valangin-ian), and considerably later in Spiti and Zanskar (Aptian/Albian) to the west. This apparent westward migration of magmatism was explained with progressive westward propagation of extensional/transtensional tectonic activity and development of fractures cutting deeply across the Indian continental margin crust. However, detrital zircon geochronology provides no indi-cation of heterochroneity in magmatic activity in the source areas from east to west, and thus lends little support to such a scenario. Westward migration of volcaniclastic sedimentation may thus relfect instead the westward progradation of major drainage systems supplying vol-canic detritus sourced from the same volcanic centers in the east. Development of multiple radial drainage away from the domal surface uplift associated with magmatic upwelling, as observed for most large igneous provinces around the world, may also explain why U–Pb ages of detrital zircons tend to cluster around 133–132 Ma (the age of the Comei igneous province) in Tethys Himalayan units, but around 118–117 Ma (the age of the Rajmahal igneous province) in Lesser Himalayan units.

  17. Central system of Interlock of ITER, high integrity architecture

    International Nuclear Information System (INIS)

    The CIS (Central Interlock System), along with the CODAC system and CSS (Central Safety System), form the central I and C systems of ITER. The CIS is responsible for implementing the core functions of protection (Central Interlock Functions) through different systems of plant (Plant Systems) within the overall strategy of investment protection for ITER. IBERDROLA supports engineering to define and develop the control architecture of CIS according to the stringent requirements of integrity, availability and response time. For functions with response times of the order of half a second is selected PLC High availability of industrial range. However, due to the nature of the machine itself, certain functions must be able to act under the millisecond, so it has had to develop a solution based on FPGA (Field Programmable Gate Array) capable of meeting the requirements architecture. In this article CIS architecture is described, as well as the process for the development and validation of the selected platforms. (Author)

  18. Geochemistry of arsenic and other trace elements in a volcanic aquifer system of Kumamoto Area, Japan

    Science.gov (United States)

    Hossain, Shahadat; Hosono, Takahiro; Shimada, Jun

    2015-04-01

    Total arsenic (As), As(III) species, dissolved organic carbon (DOC), methane (CH4), sulfur isotope ratios of sulfate (δ34SSO4), major ions and trace elements were measured in groundwater collected from boreholes and wells along the flow lines of western margins of Kumamoto basin, at central part of Kyushu island in southern Japan. Kumamoto city is considered as the largest groundwater city in Japan. 100% people of this city depends on groundwater for their drinking purpose. In this study, we used trace elements data and δ34SSO4 values to better understand the processes that are likely controlling mobilization of As in this area. Arsenic concentrations ranges from 1 to 60.6 μg/L. High concentrations were found in both shallow and deep aquifers. The aquifers are composed of Quaternary volcanic (pyroclastic) flow deposits. In both aquifers, groundwaters evolve along the down flow gradient from oxidizing conditions of recharge area to the reducing conditions of stagnant area of Kumamoto plain. 40% samples from the Kumamoto plain area excced the maximum permissible limit of Japan drinking water quality standard (10 μg/L). In the reducing groundwater, As(III) constitutes typically more, however; 50% samples dominated with As(III) and 50% samples dominated with As(V) species. High As concentrations occur in anaerobic stagnant groundwaters from this plain area with high dissolved Fe, Mn, moderately dissolved HCO3, PO4, DOC and with very low concentrations of NO3 and SO4 suggesting the reducing condition of subsurface aquifer. Moderately positive correlation between As and dissolved Fe, Mn and strong negative correlation between As(III)/As(V) ratio and V, Cr and U reflect the dependence of As concentration on the reductive process. The wide range of δ34SSO4 values (6.8 to 36.1‰) indicate that sulfur is undergoing redox cycling. Highly enriched values suggesting the process was probably mediated by microbial activity. It also be noted from positive values of sulfur

  19. Disseminated encephalomyelitis-like central nervous system neoplasm in childhood.

    Science.gov (United States)

    Zhao, Jianhui; Bao, Xinhua; Fu, Na; Ye, Jintang; Li, Ting; Yuan, Yun; Zhang, Chunyu; Zhang, Yao; Zhang, Yuehua; Qin, Jiong; Wu, Xiru

    2014-08-01

    A malignant neoplasm in the central nervous system with diffuse white matter changes on magnetic resonance imaging (MRI) is rare in children. It could be misdiagnosed as acute disseminated encephalomyelitis. This report presents our experience based on 4 patients (3 male, 1 female; aged 7-13 years) whose MRI showed diffuse lesions in white matter and who were initially diagnosed with acute disseminated encephalomyelitis. All of the patients received corticosteroid therapy. After brain biopsy, the patients were diagnosed with gliomatosis cerebri, primitive neuroectodermal tumor and central nervous system lymphoma. We also provide literature reviews and discuss the differentiation of central nervous system neoplasm from acute disseminated encephalomyelitis.

  20. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    Science.gov (United States)

    Hao, Zhixin; Sun, Di

    2016-04-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after tropical volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport,therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  1. The renin-angiotensin system and the central nervous system.

    Science.gov (United States)

    Ganong, W F

    1977-04-01

    One of several factors affecting the secretion of renin by the kidneys is the sympathetic nervous system. The sympathetic input is excitatory and is mediated by beta-adrenergic receptors, which are probably located on the membranes of the juxtaglomerular cells. Stimulation of sympathetic areas in the medulla, midbrain and hypothalamus raises blood pressure and increases renin secretion, whereas stimulation of other parts of the hypothalamus decreases blood pressure and renin output. The centrally active alpha-adrenergic agonist clonidine decreases renin secretion, lowers blood pressure, inhibits ACTH and vasopressin secretion, and increases growth hormone secretion in dogs. The effects on ACTH and growth hormone are abolished by administration of phenoxybenzamine into the third ventricle, whereas the effect on blood pressure is abolished by administration of phenoxybenzamine in the fourth ventricle without any effect on the ACTH and growth hormone responses. Fourth ventricular phenoxybenzamine decreases but does not abolish the inhibitory effect of clonidine on renin secretion. Circulating angiotensin II acts on the brain via the area postrema to raise blood pressure and via the subfornical organ to increase water intake. Its effect on vasopressin secretion is debated. The brain contains a renin-like enzyme, converting enzyme, renin substrate, and angiotensin. There is debate about the nature and physiological significance of the angiotensin II-generating enzyme in the brain, and about the nature of the angiotensin I and angiotensin II that have been reported to be present in the central nervous system. However, injection of angiotensin II into the cerebral ventricles produces drinking, increased secretion of vasopressin and ACTH, and increased blood pressure. The same responses are produced by intraventricular renin. Angiotensin II also facilitates sympathetic discharge in the periphery, and the possibility that it exerts a similar action on the adrenergic neurons

  2. Origin of Miocene andesite and dacite in the Goldfield-Superstition volcanic province, central Arizona: Hybrids of mafic and silicic magma mixing

    Science.gov (United States)

    Fodor, R. V.; Johnson, Kelly G.

    2016-07-01

    The Miocene Goldfield-Superstition volcanic province (G-SVP), ∼8000 km2 in central Arizona, is composed largely of silicic pyroclastic rocks and lavas, and smaller volumes of alkalic basalt and intermediate-composition lavas. Volcanism began ∼20.5 Ma as sparse rhyolitic and mainly basaltic lavas followed by intermediate lavas, lasting until ∼19 Ma. At that time, ∼1 m.y. of silicic eruptions began, creating most of the G-SVP. Petrologic studies are available for basalts and some for silicic rocks, but petrologic/geochemical information is sparse for intermediate-composition lavas. These latter, andesites and dacites, are the focus of this study, in which we present the processes and sources responsible for their origins. Goldfield-Superstition andesites and dacites have SiO2 ∼56-70 wt.% and Na2O + K2O that qualifies some as trachy-andesite and -dacite. A prominent petrographic feature is plagioclase-phyric texture (∼11-30 vol% plagioclase), where oligoclase-andesine phenocrysts have cores surrounded by corroded, or reacted, zones, mantled by higher An% plagioclase. Where corroded zones are absent, margins are etched, curved, or embayed. Groundmass plagioclase is labradorite, also more calcic than the phenocrysts. Other minerals are quartz (subrounded; embayed), clinopyroxene, amphibole, biotite, and rare titanite and zircon. A salient compositional characteristic that provides insight to andesite-dacite origins with respect to other G-SVP rocks is revealed when using SiO2 as an index. Namely, abundances of many incompatible elements, mainly HFSE and REE, decrease over the low to high SiO2 range (i.e., abundances are lower in dacites than in co-eruptive andesites and underlying alkalic basalts). As examples: G-SVP basalts have ∼50-70 ppm La, and andesites-dacites have ∼59-22 ppm La; for Zr, basalts have ∼225-170 ppm, but most andesites-dacites have ∼180-50; for Y, basalts >20 ppm, andesites-dacites ∼18-9 ppm. To understand these trends of lower

  3. Comment on "New radiometric dating of volcanic ash layers in Periadriatic foredeep basin system, Italy"

    OpenAIRE

    Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Marra, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Sagnotti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia

    2001-01-01

    Bigazzi et al. (2000) report new geochronological data (fission-track dating) from two volcanic ash marker layers interbedded in Upper Miocene (Messinian) -Early Pleistocene sedimentary sequences in three sites from the Adriatic side of the Italian peninsula. As Bigazzi and co-authors correctly state, these data have the potential for the establishment of sound regional chronostratigraphic markers. Unfortunately, the entire stratigraphic framework in which the new fission-track an...

  4. "Suicide" Gen Therapy for Malignant Central Nervous System Tumors

    NARCIS (Netherlands)

    A.J.P.E. Vincent (Arnoud)

    1998-01-01

    textabstractDespite development in surgical techniques, chemotherapy and radiotherapy, most malignancies of the central nervous system are still devastating tumors with a poor prognosis. For example, median survival of patients with malignant gliomas (astrocytoma, oligodendroglioma or mixed rype) is

  5. [Microglial cells and development of the embryonic central nervous system].

    Science.gov (United States)

    Legendre, Pascal; Le Corronc, Hervé

    2014-02-01

    Microglia cells are the macrophages of the central nervous system with a crucial function in the homeostasis of the adult brain. However, recent studies showed that microglial cells may also have important functions during early embryonic central nervous system development. In this review we summarize recent works on the extra embryonic origin of microglia, their progenitor niche, the pattern of their invasion of the embryonic central nervous system and on interactions between embryonic microglia and their local environment during invasion. We describe microglial functions during development of embryonic neuronal networks, including their roles in neurogenesis, in angiogenesis and developmental cell death. These recent discoveries open a new field of research on the functions of neural-microglial interactions during the development of the embryonic central nervous system.

  6. Childhood Central Nervous System Germ Cell Tumors Treatment

    Science.gov (United States)

    ... the tumor responds to treatment. Newly Diagnosed CNS Teratomas Treatment of newly diagnosed mature and immature central nervous system (CNS) teratomas may include the following: Surgery to remove as ...

  7. Treatment Option Overview (Childhood Central Nervous System Embryonal Tumors)

    Science.gov (United States)

    ... children. See the PDQ summary on Adult Central Nervous System Tumors Treatment for more information on the treatment of adults. There are different types of CNS embryonal tumors. Enlarge Anatomy of the inside of the brain, showing the ...

  8. General Information about Childhood Central Nervous System Embryonal Tumors

    Science.gov (United States)

    ... children. See the PDQ summary on Adult Central Nervous System Tumors Treatment for more information on the treatment of adults. There are different types of CNS embryonal tumors. Enlarge Anatomy of the inside of the brain, showing the ...

  9. A Rare Case of Central Nervous System Tuberculosis

    OpenAIRE

    Ravish Parekh; Alexis Haftka; Ashleigh Porter

    2014-01-01

    Intracranial abscess is an extremely rare form of central nervous system (CNS) tuberculosis (TB). We describe a case of central nervous system tuberculous abscess in absence of human immunodeficiency virus (HIV) infection. A 82-year-old Middle Eastern male from Yemen was initially brought to the emergency room due to altered mental status and acute renal failure. Cross-sectional imaging revealed multiple ring enhancing lesions located in the left cerebellum and in bilateral frontal lobe as we...

  10. Radiation therapy of tumours of the central nervous system

    International Nuclear Information System (INIS)

    The aim of this work is to present the principles of radiation therapy of tumours of the central nervous system, according to the experience of the Institute of Oncology in Krakow. The text was designed primarily for the radiotherapists involved in the treatment of tumours of the central nervous system, and may be used as an auxiliary textbook for those preparing for the examination in radiotherapy. (author)

  11. Role of metallothionein-III following central nervous system damage

    DEFF Research Database (Denmark)

    Carrasco, Javier; Penkowa, Milena; Giralt, Mercedes;

    2003-01-01

    We evaluated the physiological relevance of metallothionein-III (MT-III) in the central nervous system following damage caused by a focal cryolesion onto the cortex by studying Mt3-null mice. In normal mice, dramatic astrogliosis and microgliosis and T-cell infiltration were observed in the area...... the inflammatory response elicited in the central nervous system by a cryoinjury, nor does it serve an important antioxidant role, but it may influence neuronal regeneration during the recovery process....

  12. Comprehensive study of the seismotectonics of the easter Aleutian arc and associated volcanic systems. Annual progress report, March 1, 1978--February 28, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, K.H.; Davies, J.N.; Beavan, J.; Johnson, D.; House, L.; Krause, J.; Hickman, S.; Winslow, M.; Hauptman, J.; Mori, J.; Sykes, L.R.

    1979-01-01

    Based on the historic seismic record and accurate hypocenter data obtained from the eastern Aleutian seismic network, a relationship between the subduction-zone seismicity, volcano-trench separation, and the occurrence of great thrust earthquakes has been established for the Aleutian arc. On the basis of strong-motion accelerometer data it was found that high stress drops (540 t 650 bars) were associated with two moderate-size earthquakes (m/sub b/ = 6.0 and 5.8) within the Shumagin Islands seismic gap. This indicates that near the down-dip end of the major thrust zone, at depths of about 40 km, high tectonic stresses have accumulated within the gap segment of the arc. That such accumulation of stress is presently an ongoing process is corroborated by results from geodetic precision leveling on Unga Island. The leveling data indicate tilt rates of about 1 microradian/year. The tilting is directed down towards the trench and up towards the volcanic arc. Whether the recent activity of Pavlof, Shishaldin and Westdahl volcanoes indicates transmission of high tectonic stresses from the major thrust zone to the volcanic arc is unresolved. The search for a shallow magma chamber beneath the seismically monitored Pavlof volcano is still inconclusive although large amounts of recently acquired data remain to be analyzed. A geologic reconnaissance of the Shumagin Islands and the Adjacent Alaska Peninsula revealed Quaternary uplifted marine terraces and evidence for Holocene faulting. Both findings have severe implications for long-term tectonic activity and seismic hazards in the region of this seismic gap, portions of which are presently considered for off-shore hydrocarbon exploration and development. A critical analysis of th presently operating seimic data acquisition system reveals that a major change in remote sensing and central recording equipment is urgently needed for the Pavlof, Cold Bay, and Shumagin sections of the seismic array.

  13. Centralized Goal Formation and Systemic Reform

    OpenAIRE

    Kenneth A. Strike

    1997-01-01

    This paper asks whether there are reasonable concerns about liberty raised by standards driven systemic reform. Part I explores three kinds of concerns, students' interests in autonomy and authenticity, academic freedom, and pluralism. Part II explores two ways of conceptualizing the balance between liberty and various public interests, neo-classical economics and contemporary conservative thought. The paper draws two major conclusions about standards driven systemic reform: (1) This picture ...

  14. Paleomagnetic study of Siluro-Devonian volcanic rocks from the central Lachlan Orogen: Implications for the apparent pole wander path of Gondwana

    Science.gov (United States)

    VéRard, Christian; Tait, Jennifer; Glen, Richard

    2005-06-01

    The apparent pole wander (APW) path for Gondwana is still not clearly established, in particular, for Silurian-Devonian times. A controversial debate places authors who argue for an "X path," running directly through Africa on a reconstruction of Gondwana against those who advocate a large loop passing by southern South America, the "Y path." Most of the paleomagnetic data used to draw this loop come from the Lachlan Orogen (Australia). A paleomagnetic study was carried out in the well-dated Ambone and Ural volcanics in the central subprovince of Lachlan Orogen, New South Wales. Anisotropy of magnetic susceptibility measurements confirms detailed mapping of the region and shows that these massive dacitic sills and/or lava flows are flat lying. Among the different localities studied, only one yields interpretable paleomagnetic results. Two components of magnetization can be identified: a midtemperature direction yielding a corresponding pole in Australian coordinates λ = 67.9°S/ϕ = 084.4°E (B = 5; n = 21; dp = 17.5°/dm = 23.1°) and a high-temperature direction with a corresponding VGP λ = 24.4°S/ϕ = 060.6°E (B = 5; n = 25; dp = 1.4°/dm = 2.5°). The first is interpreted as corresponding to an Early Carboniferous pole position and can be regarded as an overprint probably related to the Early Carboniferous Kanimblan orogenic event. The second does not correspond to any expected Silurian-Devonian or younger pole position. This magnetization is thought to be primary in origin; however, secular variation has apparently not been averaged out in the single lava flow sampled. Therefore the earliest Devonian paleopole position probably lies in a 30° cone around the obtained VGP, and this position can only match the X-type APW path for Gondwana. It is in particular very different from coeval poles obtained in the eastern subprovince of the Lachlan Orogen, and it is mostly used as key poles supporting the Silurian-Devonian loop for the APW path of Gondwana

  15. Wendo Koshe Pumice: The latest Holocene silicic explosive eruption product of the Corbetti Volcanic System (Southern Ethiopia)

    Science.gov (United States)

    Rapprich, Vladislav; Žáček, Vladimír; Verner, Kryštof; Erban, Vojtěch; Goslar, Tomasz; Bekele, Yewubinesh; Legesa, Firdawok; Hroch, Tomáš; Hejtmánková, Petra

    2016-01-01

    The Plinian eruption of the Wendo Koshe crater within the Corbetti Caldera occurred around 396 BC. The pumice lapilli deposit, with a thickness exceeding 10 cm, dispersed over an area of over 1000 km2 around the towns of Hawasa and Shashemene. Most of the pumice was deposited by fall-out; however, minor local pyroclastic density currents also occurred. The calculated volume of preserved pumice fall deposit (approximately 1.2 km3), combined with the estimated volume of dispersed fine ash distributed further from the volcano, corresponds to an estimated volume of 0.4 km3 (dense rock equivalent) of erupted magma. The age of the pumice eruption (396 ± 38 BC) was determined by 14C radiometric dating of a paleosoil that developed on previous pyroclastic deposits buried by the pumice. The majority of the post-caldera volcanic products are characterized by a relatively uniform chemical composition (TiO2 = 0.24-0.27 wt.%, Zr = 1300-1600 ppm, ƩREE = 920-1150 ppm) without any significant development in composition. Despite the negligible variations in composition of the magmas that erupted during the last 2500 years within the Corbetti Volcanic System, a significant change in composition was documented prior to the 396 BC Wendo Koshe younger pumice eruption. The caldera stage ignimbrite of Corbetti (TiO2 = 0.34 wt.%, Zr = 500 ppm, ƩREE = 370 ppm) and the early post-caldera obsidians are (TiO2 = 0.34 wt.%, Zr = 800 ppm, ƩREE = 410 ppm) characterized by a commenditic composition, and the character of the rhyolitic magmas shifted towards pantellerites in the post-caldera stage. The compositional contrast is confirmed also by Sr isotope ratios. The Corbetti ignimbrite is characterized by being more radiogenic (87Sr/86Sr = 0.70678) than the post-caldera obsidians (87Sr/86Sr = 0.7046-0.7047). In contrast to the trace-element concentrations, the early Chabi obsidian does not differ from younger obsidians in isotope composition. Similarly to other silicic volcanic systems of the

  16. Deformation monitoring of the 2014 dyke intrusion and eruption within the Bárðarbunga volcanic system, and associated stress triggering at neighbouring volcanoes

    Science.gov (United States)

    Parks, Michelle; Árnadóttir, Thóra; Dumont, Stéphanie; Sigmundsson, Freysteinn; Hooper, Andrew; Drouin, Vincent; Ófeigsson, Benedikt; María Friðriksdóttir, Hildur; Hreinsdóttir, Sigrún; Rafn Heimisson, Elías; Vogfjörd, Kristín; Jónsdóttir, Kristín; Hensch, Martin; Guðmundsson, Gunnar; Magnússon, Eyjólfur; Einarsson, Páll; Rut Hjartardóttir, Ásta; Pedersen, Rikke

    2015-04-01

    The recent unrest and activity within the Bárðarbunga volcanic system, Iceland was initially identified by the onset of an intense earthquake swarm on the 16th August 2014 and concurrent movement registered at several nearby continuous GPS (cGPS) sites. Over the following weeks additional cGPS stations were installed, campaign sites were reoccupied and interferograms formed using X-band satellite images. Data were analysed in near real-time and used to map ground displacements associated with the initial dyke emplacement and propagation (NE of Bárðarbunga), responsible for the sudden unrest. On the 29th August 2014, a small fissure opened up just a few kilometers to the north of the Vatnajökull ice cap, at Holuhraun. The eruption lasted only a few hours, but was followed on 31st August by the onset of a fissure eruption, characterised by lava fountaining and the extrusion of extensive lava flows. The eruption continues at the time of writing (January 2015). We demonstrate how Interferometric Synthetic Aperture Radar (InSAR) analysis, in conjunction with GPS measurements and earthquake seismicity, has been instrumental in the continued monitoring of Bárðarbunga volcanic system since the onset of unrest. We also investigate how changes in the local stress field induced by the dyke intrusion and concurrent magma withdrawal may trigger seismicity and potentially renewed activity at neighbouring volcanoes. InSAR analysis has systematically been used throughout the eruption to monitor co-eruptive displacement in the vicinity of both the dyke and the eruption site, along with major co-eruptive subsidence occurring beneath the Bárðarbunga caldera - the latter is believed to have commenced shortly after the onset of the unrest and is associated with magma withdrawal beneath the central volcano, feeding the dyke and the ongoing eruption. We use Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) techniques to generate a time series of

  17. Central Energy System Modernization at Fort Jackson, South Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Daryl R.; Chvala, William D.; Dirks, James A.

    2006-11-29

    An evaluation of technology options was conducted for the central energy systems at Fort Jackson, South Carolina. There were two objectives in conducting this study. From a broader viewpoint, the Army would like to develop a systematic approach to management of its central energy systems and selected Fort Jackson for this ''pilot'' study for a prospective Central Energy System Modernization Program. From a site-specific perspective, the objective was to identify the lowest life-cycle cost energy supply option(s) at Fort Jackson for buildings currently served by central boilers and chillers. This study was co-funded by the Army's Southeast Region and the U.S. Department of Energy's Federal Energy Management Program.

  18. Relating binary-star planetary systems to central configurations

    CERN Document Server

    Veras, Dimitri

    2016-01-01

    Binary-star exoplanetary systems are now known to be common, for both wide and close binaries. However, their orbital evolution is generally unsolvable. Special cases of the N-body problem which are in fact completely solvable include dynamical architectures known as central configurations. Here, I utilize recent advances in our knowledge of central configurations to assess the plausibility of linking them to coplanar exoplanetary binary systems. By simply restricting constituent masses to be within stellar or substellar ranges characteristic of planetary systems, I find that (i) this constraint reduces by over 90 per cent the phase space in which central configurations may occur, (ii) both equal-mass and unequal-mass binary stars admit central configurations, (iii) these configurations effectively represent different geometrical extensions of the Sun-Jupiter-Trojan-like architecture, (iv) deviations from these geometries are no greater than ten degrees, and (v) the deviation increases as the substellar masse...

  19. Response of hydrothermal system to stress transients at Lassen Volcanic Center, California, inferred from seismic interferometry with ambient noise

    Science.gov (United States)

    Taira, Taka'aki; Brenguier, Florent

    2016-10-01

    Time-lapse monitoring of seismic velocity at volcanic areas can provide unique insight into the property of hydrothermal and magmatic fluids and their temporal variability. We established a quasi real-time velocity monitoring system by using seismic interferometry with ambient noise to explore the temporal evolution of velocity in the Lassen Volcanic Center, Northern California. Our monitoring system finds temporal variability of seismic velocity in response to stress changes imparted by an earthquake and by seasonal environmental changes. Dynamic stress changes from a magnitude 5.7 local earthquake induced a 0.1 % velocity reduction at a depth of about 1 km. The seismic velocity susceptibility defined as ratio of seismic velocity change to dynamic stress change is estimated to be about 0.006 MPa-1, which suggests the Lassen hydrothermal system is marked by high-pressurized hydrothermal fluid. By combining geodetic measurements, our observation shows that the long-term seismic velocity fluctuation closely tracks snow-induced vertical deformation without time delay, which is most consistent with an hydrological load model (either elastic or poroelastic response) in which surface loading drives hydrothermal fluid diffusion that leads to an increase of opening of cracks and subsequently reductions of seismic velocity. We infer that heated-hydrothermal fluid in a vapor-dominated zone at a depth of 2-4 km range is responsible for the long-term variation in seismic velocity[Figure not available: see fulltext.

  20. Gravity study of the Central African Rift system: A model of continental disruption 1. The Ngaoundere and Abu Gabra Rifts

    Science.gov (United States)

    Browne, S. E.; Fairhead, J. D.

    1983-05-01

    A regional compilation of published and unpublished gravity data for Central Africa is presented and reveals the presence of a major rift system, called here, the Central African Rift System. It is proposed that the junction area between the Ngaoundere and Abu Gabra rift arms in Western Sudan forms an incipient intraplate, triple-junction with the as yet unfractured, but domally uplifted and volcanically active, Darfur swell. It is only the Darfur swell that shows any similarities to the uplift and rift history of East Africa. The other two rifts arms are considered to be structurally similar to the early stages of passive margin development and thus reflect more closely the initial processes of continental fragmentation than the structures associated with rifting in East Africa.

  1. Structural and functional features of central nervous system lymphatic vessels.

    Science.gov (United States)

    Louveau, Antoine; Smirnov, Igor; Keyes, Timothy J; Eccles, Jacob D; Rouhani, Sherin J; Peske, J David; Derecki, Noel C; Castle, David; Mandell, James W; Lee, Kevin S; Harris, Tajie H; Kipnis, Jonathan

    2015-07-16

    One of the characteristics of the central nervous system is the lack of a classical lymphatic drainage system. Although it is now accepted that the central nervous system undergoes constant immune surveillance that takes place within the meningeal compartment, the mechanisms governing the entrance and exit of immune cells from the central nervous system remain poorly understood. In searching for T-cell gateways into and out of the meninges, we discovered functional lymphatic vessels lining the dural sinuses. These structures express all of the molecular hallmarks of lymphatic endothelial cells, are able to carry both fluid and immune cells from the cerebrospinal fluid, and are connected to the deep cervical lymph nodes. The unique location of these vessels may have impeded their discovery to date, thereby contributing to the long-held concept of the absence of lymphatic vasculature in the central nervous system. The discovery of the central nervous system lymphatic system may call for a reassessment of basic assumptions in neuroimmunology and sheds new light on the aetiology of neuroinflammatory and neurodegenerative diseases associated with immune system dysfunction.

  2. Volcanic hazard assessment in monogenetic volcanic fields

    OpenAIRE

    Bartolini, Stefania

    2014-01-01

    Tesi realitzada a l'Institut de Ciències de la Terra “Jaume Almera” (ICTJA-CSIC) One of the most important tasks of modern volcanology, which represents a significant socio-economic implication, is to conduct hazard assessment in active volcanic systems. These volcanological studies are aimed at hazard that allows to constructing hazard maps and simulating different eruptive scenarios, and are mainly addressed to contribute to territorial planning, definition of emergency plans or managing...

  3. Geomorphological impact on agroforestry systems in the interior highlands of Nicaragua, Central America

    Science.gov (United States)

    Mentler, Axel; Wriessnig, Karin; Ottner, Franz; Schomakers, Jasmin; Benavides González, Álvaro; Cisne Contreras, José Dolores; Querol Lipcovich, Daniel

    2013-04-01

    Cerro el Castillo is located in the NW of Nicaragua, Central America, close to the border of Honduras (Provincia Central de las Cordilleras) at 1000-1200m above sea level. In this region, small and medium-sized farms are agroforestry systems with mangos, avocados, coffee, papayas, bananas, strawberries, maize, pumpkins, beans and other vegetables. The production systems are strongly linked to facilities for raising small domestic animals and cows. Main regional agricultural production problems are steep slopes, soil erosion, varying precipitation and distribution, water management and the unstable family income. An investigation of topsoil properties with comparable management systems showed on small scales significant differences in key values of soil chemistry and mineralogy. The outline of the analytical parameters included determination of pH, electrical conductivity (EC), cation exchange capacity (CEC), organic carbon (TOC), dissolved organic carbon (DOC), total nitrogen (TN) and dissolved nitrogen (DN) in soil solution, and plant available nutrients (P and K). The soil's mineralogical composition was determined by X-ray diffraction analysis. The area is a highly weathered karst landscape within a tropical limestone region displaying different amounts of volcanic pyroclastic parent material. The dominant Nitisoils and Andosols show degraded argic and andic horizons along the upper half of the mountainside. The pH values in the topsoil are moderate from pH 5.0 to 5.6. The upland topsoil is decalcified and the amount of plant available phosphorous is very low with significant low Ca concentration at the sorption complex. The mineralogical composition points to the high weathering intensity of this area (high content of kaolinite and a lower concentration of potassium and plagioclase feldspars and andesite). Along the upper half of the mountain, the soil profiles show wider C:N ratios and lower amounts of organic matter. Topsoil at lower altitude and with a lower

  4. Development and relationship of monogenetic and polygenetic volcanic fields in time and space.

    Science.gov (United States)

    Germa, Aurelie; Connor, Chuck; Connor, Laura; Malservisi, Rocco

    2013-04-01

    The classification of volcanic systems, developed by G. P. L. Walker and colleagues, relates volcano morphology to magma transport and eruption processes. In general, distributed monogenetic volcanic fields are characterized by infrequent eruptions, low average output rate, and a low spatial intensity of the eruptive vents. In contrast, central-vent-dominated systems, such as stratovolcanoes, central volcanoes and lava shields are characterized by frequent eruptions, higher average flux rates, and higher spatial intensity of eruptive vents. However, it has been observed that a stratovolcano is often associated to parasitic monogenetic vents on its flanks, related to the central silicic systems, and surrounded by an apron of monogenetic edifices that are part of the volcanic field but independent from the principal central system. It appears from spatial distribution and time-volume relationships that surface area of monogenetic fields reflects the lateral extent of the magma source region and the lack of magma focusing mechanisms. In contrast, magma is focused through a unique conduit system for polygenetic volcanoes, provided by a thermally and mechanically favorable pathway toward the surface that is maintained by frequent and favorable stress conditions. We plan to relate surface observations of spatio-temporal location of eruptive vents and evolution of the field area through time to processes that control magma focusing during ascent and storage in the crust. We choose to study fields that range from dispersed to central-vent dominated, through transitional fields (central felsic system with peripheral field of monogenetic vents independent from the rhyolitic system). We investigate different well-studied volcanic fields in the Western US and Western Europe in order to assess influence of the geodynamic setting and tectonic stress on the spatial distribution of magmatism. In summary, incremental spatial intensity maps should reveal how fast a central conduit

  5. Aerosols Monitoring Network to Create a Volcanic ASH Risk Management System in Argentina and Chile

    Science.gov (United States)

    Quel, Eduardo; Sugimoto, Nobuo; Otero, Lidia; Jin, Yoshitaka; Ristori, Pablo; Nishizawa, Tomoaki; González, Francisco; Papandrea, Sebastián; Shimizu, Atsushi; Mizuno, Akira

    2016-06-01

    Two main decisions were made in Argentina to mitigate the impact of the recent volcanic activity in de country basically affected by the presence of volcanic ash in the air and deposited over the Argentinean territory. The first one was to create a risk management commission were this risk between others were studied, and second to develop new ground based remote sensing technologies to be able to identify and inform the risk close to the airports. In addition the Japanese government program for Science and Technology joint Research Partnership between Argentina, Chile and Japan for Sustainable Development (SATREPS) accepted to fund this cooperation due to the potential future utilization of the research outcomes to the benefit of the society. This work present the actual achievements and expected advance of these projects that try to joint efforts between national and international agencies as well as countries on behalf of a better understanding of the risks and a joint collaboration on the mitigation of suspended ashes impact over the aerial navigation.

  6. Modelling profitable and sustainable farming systems in Central Queensland

    OpenAIRE

    Chudleigh, Fred; Cox, Howard W.; Chapman, Veronica J.

    2002-01-01

    Central Queensland’s dryland farming systems are subject to high levels of climatic variability, are seen as being relatively risky and also suffering falling profitability due (in part) to the rapid decline of nutrient content and physical structure of soils. This suggests that many farming practices in Central Queensland are not sustainable. A multi agency project that uses participatory on-farm research and development processes has been addressing the core issues that contribute to more s...

  7. Demand modelling for central heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Heller, A.

    2000-07-01

    Most researchers in the field of heat demand estimation have focussed on explaning the load for a given plant based on rather few measurements. This approach is simply the only one adaptable with the very limited data material and limited computer power. This way of dealing with the subject is here called the top-down approach, due to the fact that one tries to explain the load from the overall data. The results of such efforts are discussed in the report, leading to inspiration for own work. Also the significance of the findings to the causes for given heat loads are discussed and summarised. Contrary to the top-down approach applied in literature, a here-called bottom-up approach is applied in this work, describing the causes of a given partial load in detail and combining them to explain the total load for the system. Three partial load 'components' are discussed: 1) Space heating. 2) Hot-Water Consumption. 3) Heat losses in pipe networks. The report is aimed at giving an introduction to these subjects, but at the same time at collecting the previous work done by the author. Space heating is shortly discussed and loads are generated by an advanced simulation model. A hot water consumption model is presented and heat loads, generated by this model, utilised in the overall work. Heat loads due to heat losses in district heating a given a high priority in the current work. Hence a detailed presentation and overview of the subject is given to solar heating experts normally not dealing with district heating. Based on the 'partial' loads generated by the above-mentioned method, an overall load model is built in the computer simulation environment TRNSYS. The final tool is then employed for the generation of time series for heat demand, representing a district heating area. The results are compared to alternative methods for the generation of heat demand profiles. Results form this comparison will be presented. Computerised modelling of systems

  8. Diverse roles of neurotensin agonists in the central nervous system

    Directory of Open Access Journals (Sweden)

    Mona eBoules

    2013-03-01

    Full Text Available NT is a tridecapeptide that is found in the central nervous system and the gastrointestinal tract. NT behaves as a neurotransmitter in the brain and as a hormone in the gut. Additionally, NT acts as a neuromodulator to several neurotransmitter systems including dopaminergic, sertonergic, GABAergic, glutamatergic and cholinergic systems. Due to its association with such a wide variety of neurotransmitters, NT has been implicated in the pathophysiology of several central nervous system (CNS disorders such as schizophrenia, drug abuse, Parkinson’s disease, pain, central control of blood pressure, eating disorders, as well as, cancer and inflammation. The present review will focus on the role that NT and its analogs play in schizophrenia, endocrine function, pain, psychostimulant abuse, and Parkinson’s disease.

  9. A 200kW central receiver CPV system

    Energy Technology Data Exchange (ETDEWEB)

    Lasich, John, E-mail: jbl@raygen.com; Thomas, Ian, E-mail: ithomas@raygen.com; Hertaeg, Wolfgang; Shirley, David; Faragher, Neil; Erenstrom, Neil; Carter, Sam; Cox, Brian; Zuo, Xinyi [Raygen Resources Pty. Ltd., 15 King Street, Blackburn, Victoria, 3130 (Australia)

    2015-09-28

    Raygen Resources has recently completed a Central Receiver CPV (CSPV) pilot plant in Central Victoria, Australia. The system is under final commissioning and initial operation is expected in late April 2015. The pilot demonstrates a full scale CSPV repeatable unit in a form that is representative of a commercial product and provides a test bed to prove out performance and reliability of the CSPV technology. Extensive testing of the system key components: dense array module, wireless solar powered heliostat and control system has been performed in the laboratory and on sun. Results from this key component testing are presented herein.

  10. A 200kW central receiver CPV system

    Science.gov (United States)

    Lasich, John; Thomas, Ian; Hertaeg, Wolfgang; Shirley, David; Faragher, Neil; Erenstrom, Neil; Carter, Sam; Cox, Brian; Zuo, Xinyi

    2015-09-01

    Raygen Resources has recently completed a Central Receiver CPV (CSPV) pilot plant in Central Victoria, Australia. The system is under final commissioning and initial operation is expected in late April 2015. The pilot demonstrates a full scale CSPV repeatable unit in a form that is representative of a commercial product and provides a test bed to prove out performance and reliability of the CSPV technology. Extensive testing of the system key components: dense array module, wireless solar powered heliostat and control system has been performed in the laboratory and on sun. Results from this key component testing are presented herein.

  11. A magma-hydrothermal system beneath Hakone volcano, central Japan, revealed by highly resolved velocity structures

    Science.gov (United States)

    Yukutake, Yohei; Honda, Ryou; Harada, Masatake; Arai, Ryuta; Matsubara, Makoto

    2015-05-01

    High-resolution images of subsurface structures are necessary to understand the transport processes of crustal fluids from deep magma sources and their relationship to earthquake swarms in active volcanic regions. Based on a seismic tomography approach, we have developed a new model for the magma-hydrothermal system beneath Hakone volcano, central Japan, where shallow earthquake swarms and crustal deformation associated with inflation of an open-crack source are often observed. By applying travel-time data for local earthquakes to a tomographic inversion, we obtained highly resolved seismic velocity structures that show a region of low P-wave velocity (Vp), low S-wave velocity (Vs), and high Vp/Vs ratios at depths of 10-20 km beneath the volcano, corresponding to the location of the open-crack source. We suggest that the high Vp/Vs ratios represent a deep magma chamber with a high concentration of melt and/or fluids. Deep low-frequency earthquakes, located just beneath this high Vp/Vs zone, may indicate that magmatic fluids are supplied from below. Above the high Vp/Vs zone, a region of low Vp, low Vs, and low Vp/Vs ratios exists at depths of 3-10 km, suggesting the presence of crack-filled water or CO2 supplied from the inferred deep magma chamber. Many earthquake swarms occur in this low Vp/Vs zone, indicating that crustal fluids play an important role in generating the swarms. Similar relationships between magma reservoirs, overlying hydrothermal systems, and swarm activity have been reported from other volcanic areas and thus may be a ubiquitous feature beneath active volcanoes.

  12. Influence of explosive volcanic events on the activation versus de-activation of a modern turbidite system: the example of the Dohrn canyon-fan in the continental slope of the Campania volcanic district (Naples Bay, Italy - Western Mediterranean)

    Science.gov (United States)

    Roca, M.; Budillon, F.; Pappone, G.; Insinga, D.

    2015-12-01

    The interplay between volcanic activity, volcano-clastic yield and activation/deactivation of a turbidite system can be evaluated along the continental margin of Campania region (Tyrrhenian Sea - Italy), an active volcanic area, where three wide canyon-fans occur at short distances one to another. Actually, the Dohrn, Magnaghi and Cuma canyons cut the continental slope and shelf off Ischia and Procida volcanic islands and off the Campania Plain where Phlegraean Field and Mt. Vesuvius active vents are located. This research, partly supported by the Italian Flagship Project Ritmare, is based on single-channel, high-resolution seismic profiles (Sparker-One 16 kJ, 0.5 s twtt), swath-bathymetry and litho- and tephra-stratigraphy of gravity cores. We focused on the stratigraphic constraint of paleo-thalweg features and channel/levees deposits in seismics, debris flow, turbidites and hemipelagites in cores, to learn more on the activation/deactivation stages of the canyon Dohrn, in the frame of relative eustatic sea level variations over the Middle Pleistocene-Holocene time span.Preliminary outcomes suggest that even major volcanic events occurred in the last 300 ky, such as ignimbrite eruptions or large fallouts, have caused the infilling of the canyon head and the cover of pre-existing seabed morphology. As a consequence, the temporary deactivation of the turbidite system has occurred, despite the volcano-clastic overload in the coastal environment. Phases of renewed activities of the thalweg are observed to be in step with falling stages of sea level, which have driven the re-incision of canyon valleys through continuous volcano-clastic debris and turbidites down-flows. Since Holocene, the quiescence of the Dohrn Canyon has been documented, despite the intense volcano-tectonic activity in the area.

  13. Thermal Environment for Classrooms. Central System Approach to Air Conditioning.

    Science.gov (United States)

    Triechler, Walter W.

    This speech compares the air conditioning requirements of high-rise office buildings with those of large centralized school complexes. A description of one particular air conditioning system provides information about the system's arrangement, functions, performance efficiency, and cost effectiveness. (MLF)

  14. Chemical and isotopic compositions of minerals and waters from the Campi Flegrei volcanic system, Naples, Italy

    Science.gov (United States)

    Valentino, G. M.; Cortecci, G.; Franco, E.; Stanzione, D.

    1999-08-01

    Based on their δ 34S signature, sulfate minerals and native sulfur around fumaroles and hot water pools from the Campi Flegrei volcanic area derive from supergenic oxidation of volcanic H 2S. Their mean δ 34S value (-0.2±1.7‰) matches with that of fumarolic H 2S at Solfatara (-0.3±0.3‰), as well as with the δ 34S of +1.4‰ obtained for total sulfur in fresh trachyte from the area. All δ 34S values indicate a mostly deep-seated origin for sulfur. Thermal waters were analysed for major and minor chemistry and for oxygen, hydrogen and sulfur isotope compositions. Pools at Pisciarelli are filled with evaporated meteoric water heated by rising (magmatic) gases. The water δ 18O (+3.8±1.3‰) and δ 2H (+6.5±2.2‰) values in these steam-heated waters are controlled by mixing and evaporation effects, and the δ 34S value of dissolved sulfate (-1.3±0.3‰) basically agrees with supergenic oxidation of deep-seated H 2S as the major source of sulfur. Instead, water from thermal springs and wells elsewhere in the Campi Flegrei appears to be a mixture between dilute meteoric and saline marine components. The latter may be local seawater from the bay of Pozzuoli. The δ 18O and δ 2H values of waters sampled during 1993-1994 range from -5.6 to +0.3‰ and from -33 to -3.4‰, respectively. The δ 34S values of dissolved sulfate range between -0.1 and +19.5‰. In general, sulfate is probably derived essentially from two sources, both within the volcanic cover, i.e., oxidation/dissolution of pyrite and anhydrite, and marine water. An occasional source of water and sulfate is represented by (magmatic) gases, which directly interact with shallow meteoric water as in the case of the Hotel Tennis well yielding steam-heated water with δ 18O=-1.5±0.2‰, δ 2H=-17±1‰ and δ 34S=-0.1‰.

  15. Climate effects on volcanism: influence on magmatic systems of loading and unloading from ice mass variations, with examples from Iceland.

    Science.gov (United States)

    Sigmundsson, Freysteinn; Pinel, Virginie; Lund, Björn; Albino, Fabien; Pagli, Carolina; Geirsson, Halldór; Sturkell, Erik

    2010-05-28

    Pressure influences both magma production and the failure of magma chambers. Changes in pressure interact with the local tectonic settings and can affect magmatic activity. Present-day reduction in ice load on subglacial volcanoes due to global warming is modifying pressure conditions in magmatic systems. The large pulse in volcanic production at the end of the last glaciation in Iceland suggests a link between unloading and volcanism, and models of that process can help to evaluate future scenarios. A viscoelastic model of glacio-isostatic adjustment that considers melt generation demonstrates how surface unloading may lead to a pulse in magmatic activity. Iceland's ice caps have been thinning since 1890 and glacial rebound at rates exceeding 20 mm yr(-1) is ongoing. Modelling predicts a significant amount of 'additional' magma generation under Iceland due to ice retreat. The unloading also influences stress conditions in shallow magma chambers, modifying their failure conditions in a manner that depends critically on ice retreat, the shape and depth of magma chambers as well as the compressibility of the magma. An annual cycle of land elevation in Iceland, due to seasonal variation of ice mass, indicates an annual modulation of failure conditions in subglacial magma chambers.

  16. Fermi Problem: Power developed at the eruption of the Puyehue-Cord\\'on Caulle volcanic system in June 2011

    CERN Document Server

    Asorey, Hernan

    2011-01-01

    On June 4 2011 the Puyehue-Cord\\'on Caulle volcanic system produced a pyroclastic subplinian eruption reaching level 3 in the volcanic explosivity index. The first stage of the eruption released sand and ashes that affected small towns and cities in the surrounding areas, including San Carlos de Bariloche, in Argentina, one of the largest cities in the North Patagonian andean region. By treating the eruption as a Fermi problem, we estimated the volume and mass of sand ejected as well as the energy and power released during the eruptive phase. We then put the results in context by comparing the obtained values with everyday quantities, like the load of a cargo truck or the electric power produced in Argentina. These calculations have been done as a pedagogic exercise, and after evaluation of the hypothesis was done in the classroom, the calculations have been performed by the students. These are students of the first physics course at the Physics and Chemistry Teacher Programs of the Universidad Nacional de R\\...

  17. A Linearized Model for Wave Propagation through Coupled Volcanic Conduit-crack Systems Filled with Multiphase Magma

    Science.gov (United States)

    Liang, C.; Dunham, E. M.; OReilly, O. J.; Karlstrom, L.

    2015-12-01

    Both the oscillation of magma in volcanic conduits and resonance of fluid-filled cracks (dikes and sills) are appealing explanations for very long period signals recorded at many active volcanoes. While these processes have been studied in isolation, real volcanic systems involve interconnected networks of conduits and cracks. The overall objective of our work is to develop a model of wave propagation and ultimately eruptive fluid dynamics through this coupled system. Here, we present a linearized model for wave propagation through a conduit with multiple cracks branching off of it. The fluid is compressible and viscous, and is comprised of a mixture of liquid melt and gas bubbles. Nonequilibrium bubble growth and resorption (BGR) is quantified by introducing a time scale for mass exchange between phases, following the treatment in Karlstrom and Dunham (2015). We start by deriving the dispersion relation for crack waves travelling along the multiphase-magma-filled crack embedded in an elastic solid. Dissipation arises from magma viscosity, nonequilibrium BGR, and radiation of seismic waves into the solid. We next introduce coupling conditions between the conduit and crack, expressing conservation of mass and the balance of forces across the junction. Waves in the conduit, like those in the crack, are influenced by nonequilibrium BGR, but the deformability of the surrounding solid is far less important than for cracks. Solution of the coupled system of equations provides the evolution of pressure and fluid velocity within the conduit-crack system. The system has various resonant modes that are sensitive to fluid properties and to the geometry of the conduit and cracks. Numerical modeling of seismic waves in the solid allows us to generate synthetic seismograms.

  18. Gait Rehabilitation Device in Central Nervous System Disease: A Review

    Directory of Open Access Journals (Sweden)

    Kazuya Kubo

    2011-01-01

    Full Text Available Central nervous system diseases cause the gait disorder. Early rehabilitation of a patient with central nervous system disease is shown to be benefit. However, early gait training is difficult because of muscular weakness and those elderly patients who lose of leg muscular power. In the patient's walking training, therapists assist the movement of patient's lower limbs and control the movement of patient's lower limbs. However the assistance for the movement of the lower limbs is a serious hard labor for therapists. Therefore, research into and development of various gait rehabilitation devices is currently underway to identify methods to alleviate the physical burden on therapists. In this paper, we introduced the about gait rehabilitation devices in central nervous system disease.

  19. Histologic examination of the rat central nervous system after intrathecal administration of human beta-endorphin

    DEFF Research Database (Denmark)

    Hée, P.; Klinken, Leif; Ballegaard, Martin

    1992-01-01

    Neuropathology, analgesics - intrathecal, central nervous system, histology, human beta-endorphin, toxicity......Neuropathology, analgesics - intrathecal, central nervous system, histology, human beta-endorphin, toxicity...

  20. Diagnosis of Fetal Central Nervous System Anomalies by Ultrasonography

    Directory of Open Access Journals (Sweden)

    F. Tuncay Ozgunen

    2003-04-01

    Full Text Available During the last 30 years, one of the most important instruments in diagnosis is ultrasonograph. It has an indispensible place in obstetrics. Its it possible to evaluate normal fetal anatomy, to follow-up fetal growth and to diagnose fetal congenital anomalies by ultrasonography. Central nervous system anomalies is the one of the most commonly seen and the best time for screening is between 18- and 22-week of pregnancy. In this paper, it is presented the sonographic features of some outstanding Central Nervous System anomalies. [Archives Medical Review Journal 2003; 12(2.000: 77-89

  1. SUPERSYMMETRIC INVARIANCE AND UNIVERSAL CENTRAL EXTENSIONS OF LIE SUPERTRIPLE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    张庆成; 魏竹; 禇颖娜; 张永平

    2014-01-01

    In this article, we discuss some properties of a supersymmetric invariant bilinear form on Lie supertriple systems. In particular, a supersymmetric invariant bilinear form on Lie supertriple systems can be extended to its standard imbedding Lie superalgebras. Furthermore, we generalize Garland’s theory of universal central extensions for Lie supertriple systems following the classical one for Lie superalgebras. We solve the problems of lifting automorphisms and lifting derivations.

  2. Blind Geothermal System Exploration in Active Volcanic Environments; Multi-phase Geophysical and Geochemical Surveys in Overt and Subtle Volcanic Systems, Hawai’i and Maui

    Energy Technology Data Exchange (ETDEWEB)

    Fercho, Steven [Ormat Nevada, Inc., Reno, NV (United States); Owens, Lara [Ormat Nevada, Inc., Reno, NV (United States); Walsh, Patrick [Ormat Nevada, Inc., Reno, NV (United States); Drakos, Peter [Ormat Nevada, Inc., Reno, NV (United States); Martini, Brigette [Corescan Inc., Ascot (Australia); Lewicki, Jennifer L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kennedy, Burton M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-08-01

    Suites of new geophysical and geochemical exploration surveys were conducted to provide evidence for geothermal resource at the Haleakala Southwest Rift Zone (HSWRZ) on Maui Island, Hawai’i. Ground-based gravity (~400 stations) coupled with heli-bourne magnetics (~1500 line kilometers) define both deep and shallow fractures/faults, while also delineating potentially widespread subsurface hydrothermal alteration on the lower flanks (below approximately 1800 feet a.s.l.). Multi-level, upward continuation calculations and 2-D gravity and magnetic modeling provide information on source depths, but lack of lithologic information leaves ambiguity in the estimates. Additionally, several well-defined gravity lows (possibly vent zones) lie coincident with magnetic highs suggesting the presence of dike intrusions at depth which may represent a potentially young source of heat. Soil CO2 fluxes were measured along transects across geophysically-defined faults and fractures as well as young cinder cones along the HSWRZ. This survey generally did not detect CO2 levels above background, with the exception of a weak anomalous flux signal over one young cinder cone. The general lack of observed CO2 flux signals on the HSWRZ is likely due to a combination of lower magmatic CO2 fluxes and relatively high biogenic surface CO2 fluxes which mix with the magmatic signal. Similar surveys at the Puna geothermal field on the Kilauea Lower East Rift Zone (KLERZ) also showed a lack of surface CO2 flux signals, however aqueous geochemistry indicated contribution of magmatic CO2 and He to shallow groundwater here. As magma has been intercepted in geothermal drilling at the Puna field, the lack of measured surface CO2 flux indicative of upflow of magmatic fluids here is likely due to effective “scrubbing” by high groundwater and a mature hydrothermal system. Dissolved inorganic carbon (DIC) concentrations, δ13C compositions and 3He/4He values were sampled at Maui from several shallow

  3. Central retinal vein occlusion: A patient with systemic sclerosis

    Directory of Open Access Journals (Sweden)

    Karadžić Jelena

    2016-01-01

    Full Text Available Introduction. Scleroderma (systemic sclerosis is a severe chronic connective tissue disease, which results in involvement of numerous internal organs. Changes in the eye are the consequences of organ-specific manifestations of scleroderma or adverse effects of immunosuppressive treatment applied. Case report. We reported a 42-year-old woman with systemic sclerosis and acute deterioration of vision in the left eye, with visual acuity 0.9. After thorough clinical examination, including fluorescein angiography and optical coherence tomography, the diagnosis of nonischemic central retinal vein occlusion was made. Further biochemical, rheumatological and immunological investigation, apart from inactive systemic sclerosis, showed normal findings. Therefore, the cause of central retinal vein occlusion could only be attributed to the microvascular changes in systemic sclerosis. After three months, visual acuity deteriorated to 0.6 due to the development of cystoid macular edema. The patient received intravitreal injection of bevacizumab and after a single dose visual acuity improved to 0.9. After a 6- month follow-up, macular edema resolved and visual acuity stabilized. Conclusion. According to our knowledge and current data from the literature, central retinal vein occlusion is a rare vision threatening manifestation of scleroderma. There are only few published case reports on central vein occlusion in scleroderma patients. Examination of the ocular fundus is recommended for evaluation of vascular disease in patients with systemic sclerosis.

  4. Relating binary-star planetary systems to central configurations

    Science.gov (United States)

    Veras, Dimitri

    2016-11-01

    Binary-star exoplanetary systems are now known to be common, for both wide and close binaries. However, their orbital evolution is generally unsolvable. Special cases of the N-body problem which are in fact completely solvable include dynamical architectures known as central configurations. Here, I utilize recent advances in our knowledge of central configurations to assess the plausibility of linking them to coplanar exoplanetary binary systems. By simply restricting constituent masses to be within stellar or substellar ranges characteristic of planetary systems, I find that (i) this constraint reduces by over 90 per cent the phase space in which central configurations may occur, (ii) both equal-mass and unequal-mass binary stars admit central configurations, (iii) these configurations effectively represent different geometrical extensions of the Sun-Jupiter-Trojan-like architecture, (iv) deviations from these geometries are no greater than 10°, and (v) the deviation increases as the substellar masses increase. This study may help restrict future stability analyses to architectures which resemble exoplanetary systems, and might hint at where observers may discover dust, asteroids and/or planets in binary-star systems.

  5. Reconciling Himalayan midcrustal discontinuities: The Main Central thrust system

    Science.gov (United States)

    Larson, Kyle P.; Ambrose, Tyler K.; Webb, A. Alexander G.; Cottle, John M.; Shrestha, Sudip

    2015-11-01

    The occurrence of thrust-sense tectonometamorphic discontinuities within the exhumed Himalayan metamorphic core can be explained as part of the Main Central thrust system. This imbricate thrust structure, which significantly thickened the orogenic midcrustal core, comprises a series of thrust-sense faults that all merge into a single detachment. The existence of these various structures, and their potential for complex overprinting along the main detachment, may help explain the contention surrounding the definition, mapping, and interpretation of the Main Central thrust. The unique evolution of specific segments of the Main Central thrust system along the orogen is interpreted to be a reflection of the inherent basement structure and ramp position, and structural level of exposure of the mid-crust. This helps explain the variation in the timing and structural position of tectonometamorphic discontinuities along the length of the mountain belt.

  6. Aren't technological choices central to designing health systems?

    Science.gov (United States)

    Priya, Ritu

    2013-01-01

    This paper argues that delivery of technology-based preventive, promotive and curative care is one of the central tasks of any health-care system and therefore it forms one of the central pivots for rational structuring/re-structuring of a health-care system. The development of our public health system has, historically, adopted health technologies (HT) uncritically and thereby not explicitly developed institutional mechanisms to assess them for rational choice. Determinants of HT policy choices and structuring of a service delivery system based on that are discussed with examples of modern low cost HT, technologies of codified health knowledge systems other than the modern and local health traditions. Various forms of institutional structures for HT assessment and R and D using a comprehensive primary health-care approach are suggested. PMID:24351381

  7. Aren′t technological choices central to designing health systems?

    Directory of Open Access Journals (Sweden)

    Ritu Priya

    2013-01-01

    Full Text Available This paper argues that delivery of technology-based preventive, promotive and curative care is one of the central tasks of any health-care system and therefore it forms one of the central pivots for rational structuring/re-structuring of a health-care system. The development of our public health system has, historically, adopted health technologies (HT uncritically and thereby not explicitly developed institutional mechanisms to assess them for rational choice. Determinants of HT policy choices and structuring of a service delivery system based on that are discussed with examples of modern low cost HT, technologies of codified health knowledge systems other than the modern and local health traditions. Various forms of institutional structures for HT assessment and R and D using a comprehensive primary health-care approach are suggested.

  8. Comparative Performance Assessment For Central Receiver CPV Systems

    Science.gov (United States)

    Lasich, John B.; Thomas, Ian; Verlinden, Pierre J.; Lewandowski, Allan; Heartag, Wolfgang; Wright, Mark

    2011-12-01

    A Central receiver Concentrating PV (C2PV) system has the potential to be the optimum solar energy generation system for utility scale because it combines the high efficiency of CPV with the low cost of a heliostat collector. Due to the off axis nature of a heliostat central receiver concentrator a cosine efficiency loss is incurred and, unlike `normal' tracking CPV lens and dish systems, the optical performance varies with time and site latitude. To investigate the optical performance of a C2PV system a ray trace model has been developed and the performance of a representative C2PV system is modelled throughout the year and at different site latitudes. The cosine loss and latitude dependence are put into perspective by calculating the annual average optical efficiency and testing its sensitivity to variations in site latitude. These values are then used to estimate a system performance by applying efficiencies for solar cell, balance of system and operational factors. This system efficiency is finally compared to published data for `normal' tracking CPV dish and lens systems. Modelled annual average AC system efficiency for the C2PV system was calculated to be 21% at 40° latitude and 19% at 15° latitude. These annual average AC system efficiencies are shown to be similar to those reported for typical dish and lens CPV systems when they are adjusted to use a total collector area baseline.

  9. Extreme Cost Reductions with Multi-Megawatt Centralized Inverter Systems

    Energy Technology Data Exchange (ETDEWEB)

    Schwabe, Ulrich [Alencon LLC; Fishman, Oleg [Alencon LLC

    2015-03-20

    The objective of this project was to fully develop, demonstrate, and commercialize a new type of utility scale PV system. Based on patented technology, this includes the development of a truly centralized inverter system with capacities up to 100MW, and a high voltage, distributed harvesting approach. This system promises to greatly impact both the energy yield from large scale PV systems by reducing losses and increasing yield from mismatched arrays, as well as reduce overall system costs through very cost effective conversion and BOS cost reductions enabled by higher voltage operation.

  10. Imaging in the infectious diseases of the central nervous system

    International Nuclear Information System (INIS)

    The basic signs of the major bacterial, viral, parasitic or mycotic infections of the central nervous system with CT and MRI are described. The problems arising from the presence of the HIV virus are emphasized and the attitude required according to the findings of imaging, is defined

  11. Tuberculosis of the central nervous system : overview of neuroradiological findings

    NARCIS (Netherlands)

    Bernaerts, A; Vanhoenacker, FM; Parizel, PM; van Altena, R; Laridon, A; De Roeck, J; Coeman, [No Value; De Schepper, AM; Goethem, J.W.M.

    2003-01-01

    This article presents the range of manifestations of tuberculosis (TB) of the craniospinal axis. Central nervous system (CNS) infection with Mycobacterium tuberculosis occurs either in a diffuse form as basal exudative leptomeningitis or in a localized form as tuberculoma, abscess, or cerebritis. In

  12. Neuronal chemokines : Versatile messengers in central nervous system cell interaction

    NARCIS (Netherlands)

    de Haas, A. H.; van Weering, H. R. J.; de Jong, E. K.; Boddeke, H. W. G. M.; Biber, K. P. H.

    2007-01-01

    Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS), chemoki

  13. 77 FR 33215 - Changes to the Central Data Exchange System

    Science.gov (United States)

    2012-06-05

    ... announces EPA's plans to take advantage of opportunities offered by evolving technologies to improve CDX...: Notice. SUMMARY: In compliance with the Cross-Media Electronic Reporting Regulation (CROMERR), this notice announces EPA's plan to change its Central Data Exchange (CDX) system, as described in this...

  14. A centralized dose calculation system for radiation therapy.

    Science.gov (United States)

    Xiao, Y; Galvin, J

    2000-05-01

    Centralization of treatment planning in a radiation therapy department is a realistic strategy to achieve an integrated and quality-controlled planning system, especially for institutions with numerous affiliations. The rapid evolution of computer hardware and software technology makes this a distinct possibility. However, the procedure of three-dimensional treatment planning involves a number of steps, such as: (1) input of patient computed tomography (CT) images and contour information; (2) interactions with local devices such as a film digitizer; and (3) output of beam information to be integrated with the record and verify the system. A full-fledged realization of the web-based centralized three-dimensional treatment planning system will require an extensive commercial development effort. We have developed and incorporated a web-based Timer/Monitor Unit (MU) program as a first step towards the full implementation of a centralized treatment planning system. The software application was developed in JAVA language. It uses the internet server and client technology. With one server that can handle multiple threads, it is a simple process to access the application anywhere on the network with an internet browser. Both the essential data needed for the calculation and the results are stored on the server, which centralizes the maintenance of the software and the storage of patient information.

  15. School Reentry for Children with Acquired Central Nervous Systems Injuries

    Science.gov (United States)

    Carney, Joan; Porter, Patricia

    2009-01-01

    Onset of acquired central nervous system (CNS) injury during the normal developmental process of childhood can have impact on cognitive, behavioral, and motor function. This alteration of function often necessitates special education programming, modifications, and accommodations in the education setting for successful school reentry. Special…

  16. Innate immune responses in central nervous system inflammation

    DEFF Research Database (Denmark)

    Finsen, Bente; Owens, Trevor

    2011-01-01

    In autoimmune diseases of the central nervous system (CNS), innate glial cell responses play a key role in determining the outcome of leukocyte infiltration. Access of leukocytes is controlled via complex interactions with glial components of the blood-brain barrier that include angiotensin II...

  17. The Role of Central Nervous System Plasticity in Tinnitus

    Science.gov (United States)

    Saunders, James C.

    2007-01-01

    Tinnitus is a vexing disorder of hearing characterized by sound sensations originating in the head without any external stimulation. The specific etiology of these sensations is uncertain but frequently associated with hearing loss. The "neurophysiogical" model of tinnitus has enhanced appreciation of central nervous system (CNS) contributions.…

  18. Fissure swarms and fracture systems within the Western Volcanic Zone, Iceland - Effects of spreading rates

    Science.gov (United States)

    Hjartardóttir, Ásta Rut; Einarsson, Páll; Björgvinsdóttir, Sigríður G.

    2016-10-01

    The Western Volcanic Zone (WVZ) in Iceland is ∼120 km long and 40 km wide. It offers an opportunity to study rift zones in a local ultra-slow spreading area close to a hotspot. Fractures were mapped from aerial photographs and digital elevation models. Most surface fractures are located in the southern part of the WVZ. The majority of the fractures have a north-northeasterly orientation, some deviations occur from this, especially in the north part of the WVZ. Fracture orientations are therefore quite uniform in the southern, faster spreading part of the WVZ, but more irregular in the slower-spreading northern part. This suggests different stress fields in the north part, which could be due to the influence of the Hreppar microplate and possibly also due to stress fields induced by crustal deformation because of changes in glacial load in the area. Such glacially-induced stress fields may have similar or even more influence than crustal spreading in the slower spreading northern part of the WVZ. Lower fracture density towards the north within the WVZ suggests lower frequency of rifting events in the north part, in accordance with less spreading in the north as measured by GPS geodetic measurements.

  19. [Spontaneous recovery of function in central nervous system lesions].

    Science.gov (United States)

    Anghinah, A

    1975-12-01

    A rewiev of the mechanisms responsible for the spontaneous recuperation of function in patients with lesions of the central nervous sistem is made. The spontaneous reorganization theories of the nervous structures and the vicarious function are also referred to. In the last two decades experimental contributions have been accentuated, specially the one conducted by the group of researchers directed by Windle and Guth, who had shown the possibility of regeneration in the central nervous system, as well Lawrende and Kuypers, Brodal, Goldberger and others, which defended the vircarious function as the probable mechanisms of recuperation. PMID:1191098

  20. Evolution of bilaterian central nervous systems: a single origin?

    OpenAIRE

    Carvalho, Joao E.; Escriva, Hector; Laudet, Vincent; Schubert, Michael; Shimeld, Sebastian M; Yu, Jr-Kai

    2013-01-01

    Abstract The question of whether the ancestral bilaterian had a central nervous system (CNS) or a diffuse ectodermal nervous system has been hotly debated. Considerable evidence supports the theory that a CNS evolved just once. However, an alternative view proposes that the chordate CNS evolved from the ectodermal nerve net of a hemichordate-like ancestral deuterostome, implying independent evolution of the CNS in chordates and protostomes. To specify morphological divisions along the ...

  1. [VARICELLA ZOSTER VIRUS AND DISEASES OF CENTRAL NERVOUS SYSTEM VESSELS].

    Science.gov (United States)

    Kazanova, A S; Lavrov, V F; Zverev, V V

    2015-01-01

    Systemized data on epidemiology, pathogenesis, clinical manifestation, diagnostics and therapy of VZV-vasculopathy--a disease, occurring due to damage of arteries of the central nervous system by Varicella Zoster virus, are presented in the review. A special attention in the paper is given to the effect of vaccine prophylaxis of chicken pox and herpes zoster on the frequency of development and course of VZV-vasculopathy. PMID:26259280

  2. Paracoccidioidomycosis case series with and without central nervous system involvement

    OpenAIRE

    Vinicius Sousa Pietra Pedroso; Ana Claudia Lyon; Stanley de Almeida Araújo; Juliana Márcia Ribeiro Veloso; Enio Roberto Pietra Pedroso; Antônio Lucio Teixeira

    2012-01-01

    INTRODUCTION: Paracoccidioidomycosis (PCM) is the most important systemic mycosis in South America. Central nervous system involvement is potentially fatal and can occur in 12.5% of cases. This paper aims to contribute to the literature describing eight cases of neuroparacoccidioidomycosis (NPMC) and compare their characteristics with patients without neurological involvement, to identify unique characteristics of NPCM. METHODS: A cohort of 213 PCM cases was evaluated at the Infectious Diseas...

  3. Axon Regeneration in the Peripheral and Central Nervous Systems

    OpenAIRE

    Huebner, Eric A.; Strittmatter, Stephen M

    2009-01-01

    Axon regeneration in the mature mammalian central nervous system (CNS) is extremely limited after injury. Consequently, functional deficits persist after spinal cord injury (SCI), traumatic brain injury, stroke, and related conditions that involve axonal disconnection. This situation differs from that in the mammalian peripheral nervous system (PNS), where long- distance axon regeneration and substantial functional recovery can occur in the adult. Both extracellular molecules and the intrinsi...

  4. The Glutamatergic Neurotransmission in the Central Nervous System

    OpenAIRE

    Marmiroli, PL; Cavaletti, GA

    2012-01-01

    Glutamate is one of the major neurotrasmitters in mammalian brain and changes in its concentration have been associated with a number of neurological disorders, including neurodegenerative, cerebrovascular diseases and epilepsy. Moreover, recently a possible role for glutamatergic system dysfunction has been suggested also in the peripheral nervous system. This chapter will revise the current knowledge in the distribution of glutamate and of its receptors and transporters in the central nervo...

  5. Geologic characterization of Cuvette Centrale petroleum systems Congo-DRC

    Energy Technology Data Exchange (ETDEWEB)

    Vicentelli, Maria Gabriela C.; Barbosa, Mauro; Rezende, Nelio G.A.M. [HRT Petroleum, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The Cuvette Centrale is an almost unexplored basin, which contains some petroleum system elements that indicate the presence of hydrocarbons. In this sense; this paper presents an exploratory alternative for this intracratonic basin. The interpretation of the limited gravimetric, magnetometric, geochemical and seismic available data allowed the identification of many huge structural features and also some areas with hydrocarbon potential for stratigraphic traps. The presence of several oil and gas seeps widespread around the Busira and Lokoro sub-basins indicate that at least one active petroleum system exist in the basin. Despite only four wells have been drilled in the basin, one of them presented oil shows during drilling. Geological correlations between Brazilian Paleozoic basins and Cuvette Centrale sedimentary sequences permitted to conclude that Cambro-Ordovician and Siluro-Devonian source rocks must be present and active in the Cuvette Centrale basin. The tectono-stratigraphic evolution history of the Cuvette Centrale from Neo proterozoic to Recent times shows extensional and compressional/transpressional alternating phases along the geological time. The most confident petroleum system expected in the Cuvette Centrale is characterized by the Cambrian Mamungi shale - source rock - and the Cambro-Ordovician. Upper Arenaceous Sequence - reservoirs, as observed in the MBandaka and Gilson wells and confirmed by surface geology in outcrops. Besides, other potential petroleum systems are expected to occur in the basin. One is characterized by the Neo proterozoic Itury Group source rock and reservoirs in the mature/over mature stage, the others are the Siluro-Devonian and Cretaceous source rocks and reservoirs, expected to occur with better maturity conditions only in the deeper parts of the basin. (author)

  6. 21 CFR 882.5550 - Central nervous system fluid shunt and components.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Central nervous system fluid shunt and components... Central nervous system fluid shunt and components. (a) Identification. A central nervous system fluid... central nervous system to an internal delivery site or an external receptacle for the purpose of......

  7. Imaging the central serotonergic system in neuropsychiatric disorders

    International Nuclear Information System (INIS)

    The central serotonergic system has an important impact on numerous functions of the central nervous system. Alterations of brain serotonergic activity have been suggested as pathophysiologically and pathogenetically relevant, especially in neuropsychiatric disorders. Therefore serotonergic imaging might be of particular scientific (and clinical) interest. Reliable PET- or SPECT imaging of serotonergic structures (receptors, transporters) is so far impaired by the complex neuroanatomical situation and several methodological limitations. Selected clinical PET- and SPECT-studies with 5HT1A/2A-receptor and serotonintransporter ligands in neuropsychiatric patients will be presented and critically discussed. To date the clinical relevance of these techniques remains to be established, however, imaging of the serotonergic system might contribute to our further knowledge of brain pathophysiology. (orig.)

  8. System Size, Energy, Pseudorapidity, and Centrality Dependence of Elliptic Flow

    Science.gov (United States)

    Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Harnarine, I.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Richardson, E.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wyngaardt, S.; Wysłouch, B.

    2007-06-01

    This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

  9. Sjogrens Syndrome Presenting with Central Nervous System Involvement

    Directory of Open Access Journals (Sweden)

    Tülay Terzi

    2012-01-01

    Full Text Available Sjogren’s syndrome is a slowly progressive autoimmune disease. Neurological involvement occurs in approximately 20-25% cases in Sjogren’s syndrome. 87% of the neurological involvement is peripheral nervous system, almost 13% in the form of central nervous system involvement. Affected central nervous system may show similar clinical and radiological findings as in multiple sclerosis (MS. In this paper, a 43-year-old patient is discussed who was referred with the complaint of dizziness, there was MS- like lesions in brain imaging studies and was diagnosed with Sjogren’s syndrome. MS- like clinical and radiologic tables can be seen, albeit rarely in Sjogren’s syndrome. In these cases, early diagnosis and early treatment for the sjögren has a great importance for the prognosis of the disease.

  10. Middle Miocene near trench volcanism in northern Colombia: A record of slab tearing due to the simultaneous subduction of the Caribbean Plate under South and Central America?

    Science.gov (United States)

    Lara, M.; Cardona, A.; Monsalve, G.; Yarce, J.; Montes, C.; Valencia, V.; Weber, M.; De La Parra, F.; Espitia, D.; López-Martínez, M.

    2013-08-01

    Field, geochemical, geochronological, biostratigraphical and sedimentary provenance results of basaltic and associated sediments northern Colombia reveal the existence of Middle Miocene (13-14 Ma) mafic volcanism within a continental margin setting usually considered as amagmatic. This basaltic volcanism is characterized by relatively high Al2O3 and Na2O values (>15%), a High-K calc-alkaline affinity, large ion lithophile enrichment and associated Nb, Ta and Ti negative anomalies which resemble High Al basalts formed by low degree of asthenospheric melting at shallow depths mixed with some additional slab input. The presence of pre-Cretaceous detrital zircons, tourmaline and rutile as well as biostratigraphic results suggest that the host sedimentary rocks were deposited in a platform setting within the South American margin. New results of P-wave residuals from northern Colombia reinforce the view of a Caribbean slab subducting under the South American margin. The absence of a mantle wedge, the upper plate setting, and proximity of this magmatism to the trench, together with geodynamic constraints suggest that the subducted Caribbean oceanic plate was fractured and a slab tear was formed within the oceanic plate. Oceanic plate fracturing is related to the splitting of the subducting Caribbean Plate due to simultaneous subduction under the Panama-Choco block and northwestern South America, and the fast overthrusting of the later onto the Caribbean oceanic plate.

  11. Classifications of central solar domestic hot water systems

    Science.gov (United States)

    Guo, J. Y.; Hao, B.; Peng, C.; Wang, S. S.

    2016-08-01

    Currently, there are many means by which to classify solar domestic hot water systems, which are often categorized according to their scope of supply, solar collector positions, and type of heat storage tank. However, the lack of systematic and scientific classification as well as the general disregard of the thermal performance of the auxiliary heat source is important to DHW systems. Thus, the primary focus of this paper is to determine a classification system for solar domestic hot water systems based on the positions of the solar collector and auxiliary heating device, both respectively and in combination. Field-testing data regarding many central solar DHW systems demonstrates that the position of the auxiliary heat source clearly reflects the operational energy consumption. The consumption of collective auxiliary heating hot water system is much higher than individual auxiliary heating hot water system. In addition, costs are significantly reduced by the separation of the heat storage tank and the auxiliary heating device.

  12. Immune response induction in the central nervous system

    DEFF Research Database (Denmark)

    Owens, Trevor; Babcock, Alicia

    2002-01-01

    The primary function of the immune response is protection of the host against infection with pathogens, including viruses. Since viruses can infect any tissue of the body, including the central nervous system (CNS), it is logical that cells of the immune system should equally have access to all...... tissues. Nevertheless, the brain and spinal cord are noted for their lack of immune presence. Relative to other organ systems, the CNS appears immunologically privileged. Furthermore, when immune responses do occur in the CNS, they are frequently associated with deleterious effects such as inflammatory...

  13. Ca-rich carbonates associated with ultrabasic-ultramafic melts: Carbonatite or limestone xenoliths? A case study from the late Miocene Morron de Villamayor volcano (Calatrava Volcanic Field, central Spain)

    Science.gov (United States)

    Lustrino, Michele; Prelević, Dejan; Agostini, Samuele; Gaeta, Mario; Di Rocco, Tommaso; Stagno, Vincenzo; Capizzi, Luca Samuele

    2016-07-01

    The volcanic products of the late Miocene Morron de Villamayor volcano (Calatrava Volcanic Field, central Spain) are known for being one of the few outcrops of leucitites in the entire circum-Mediterranean area. These rocks are important because aragonite of mantle origin has been reported as inclusion in olivine macrocrysts. We use petrographic observations, mineral compositions, as well as oxygen and carbon isotope ratios coupled with experimental petrology to understand the origin of carbonate phase in these olivine-phyric rocks. Groundmass and macrocryst olivines range from δ18OVSMOW of +4.8‰, typical of mantle olivine values, to +7.4‰, indicating contamination by sedimentary carbonate. Carbonates are characterized by heavy oxygen isotope compositions (δ18OVSMOW >+24‰), and relatively light carbon isotopes (δ13CPDB <-11‰), resembling skarn values, and distinct from typical mantle carbonatite compositions. Petrography, mineral compositions such as low Mg# of clinopyroxene and biotite, low Ca# and low incompatible element abundance of the carbonate, and isotopic ratios of O and C, do not support a mantle origin for the carbonate. Rather, the carbonate inclusions found in the olivine macrocrysts are interpreted as basement limestone fragments entrapped by the rising crystallizing magma. Comparison with experimental carbonatitic and silicate-carbonatitic melts indicates that low-degree partial melts of a carbonated peridotite must have a dolomitic rather than the aragonitic/calcitic composition as those found trapped in the Morron de Villamayor olivine macrocrysts.

  14. Managing Atypical and Typical herpetic central nervous system infections

    DEFF Research Database (Denmark)

    Cag, Yasemin; Erdem, Hakan; Leib, Stephen;

    2016-01-01

    There have been many studies pertaining to the management of herpetic meningoencephalitis (HME), but the majority of them have focused on virologically unconfirmed cases or included only small sample sizes. We have conducted a multicentre study aimed at providing management strategies for HME. Ov...... HSV-PCR, EEG and MRI data should be collected for all patients with a central nervous system infection considering the subtle nature of HME....

  15. The central nervous system in childhood chronic kidney disease.

    Science.gov (United States)

    Gipson, Debbie S; Duquette, Peter J; Icard, Phil F; Hooper, Stephen R

    2007-10-01

    Neurodevelopmental deficits in pediatric and adult survivors of childhood onset chronic kidney disease (CKD) have been documented for many years. This paper reviews the available literature on central nervous system involvement incurred in childhood CKD. The studies reviewed include recent work in neuroimaging, electrophysiology, and neuropsychology, along with commentary on school functioning and long-term outcomes. The paper concludes with suggestions for monitoring the neurodevelopmental status and pursuing appropriate early interventions for children with CKD. PMID:17072652

  16. Central nervous system infection caused by Morganella morganii.

    Science.gov (United States)

    Abdalla, Jehad; Saad, Mustafa; Samnani, Imran; Lee, Prescott; Moorman, Jonathan

    2006-01-01

    Central nervous system (CNS) infection with Morganella morganii is very rare. We describe a 38-year-old female patient with frontal brain abscess caused by M morganii who was unsuccessfully treated. We also review all reported cases of Morganella CNS infections with an emphasis on treatment modalities and outcomes. Aggressive surgical management and appropriate antimicrobial therapy can lead to cure, but the mortality rate for these infections remains high.

  17. Neuronal Chemokines: Versatile Messengers In Central Nervous System Cell Interaction

    OpenAIRE

    de Haas, A. H.; van Weering, H. R. J.; Jong, E.K.; Boddeke, H. W. G. M.; Biber, K.P.H.

    2007-01-01

    Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS), chemokines are generally found under both physiological and pathological conditions. Whereas many reports describe chemokine expression in astrocytes and microglia and their role in the migration of leuko...

  18. "Suicide" Gen Therapy for Malignant Central Nervous System Tumors

    OpenAIRE

    Vincent, Arnoud

    1998-01-01

    textabstractDespite development in surgical techniques, chemotherapy and radiotherapy, most malignancies of the central nervous system are still devastating tumors with a poor prognosis. For example, median survival of patients with malignant gliomas (astrocytoma, oligodendroglioma or mixed rype) is roughly 12 months and only 5 % of the patients survive more than 5 years after diagnosis. Fifty % of astrocytomas are ryped as glioblastoma multiforme, the most malignant form of glioma. Glioblast...

  19. Echography of congenital malformations of the central nervous system

    International Nuclear Information System (INIS)

    A descriptive and prospective study was conducted in 173 pregnant women attended at the Provincial Department of Clinical Genetics of Santiago de Cuba, from January, 2000 to December, 2004, to identify congenital malformations of the central nervous system detected by means of echography. The most frequent malformation was the hydrocephaly, followed by the fusion defects of the spine, associated with the hydrocephaly and the absence of cranial cavity. There was a prevalence of altered alpha fetoprotein and of elevated amniotic fluid

  20. Chronic Viral Infection and Primary Central Nervous System Malignancy

    OpenAIRE

    Saddawi-Konefka, Robert; Crawford, John R.

    2010-01-01

    Primary central nervous system (CNS) tumors cause significant morbidity and mortality in both adults and children. While some of the genetic and molecular mechanisms of neuro-oncogenesis are known, much less is known about possible epigenetic contributions to disease pathophysiology. Over the last several decades, chronic viral infections have been associated with a number of human malignancies. In primary CNS malignancies, two families of viruses, namely polyomavirus and herpesvirus, have be...

  1. Neurotrophic effects of neudesin in the central nervous system

    OpenAIRE

    Kimura, Ikuo; Nakayama, Yoshiaki; Zhao, Ying; Konishi, Morichika; Itoh, Nobuyuki

    2013-01-01

    Neudesin (neuron-derived neurotrophic factor; NENF) was identified as a neurotrophic factor that is involved in neuronal differentiation and survival. It is abundantly expressed in the central nervous system, and its neurotrophic activity is exerted via the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. Neudesin is also an anorexigenic factor that suppresses food intake in the hypothalamus. It is a member of the membrane-associated progesterone rece...

  2. Investigation of bubble behaviours in wet central heating systems

    OpenAIRE

    Shefik Ali; Ge Yunting

    2014-01-01

    A series of experimental measurements has been conducted in order to investigate the bubble behaviours through the horizontal pipe line of the domestic wet central heating systems. Obtained results exposed the effect of 90 degree bend, buoyancy forces on bubbly two phase flow patterns and effect of velocity on void fractions and bubble diameters. Distance chosen for the first sight glass (HSG0) was sufficient enough to note the effect of 90 degree bend on void fraction patterns. Due to the ef...

  3. Simultaneous central nervous system complications of C. neoformans infection

    Science.gov (United States)

    González-Duarte, Alejandra; Higera Calleja, Jesus; Mitre, Vicente Gijón; Ramos, Guillermo Garcia

    2009-01-01

    The most common neurological manifestation of Cryptococcus neoformans infection is meningitis. Other less common manifestations include parenchymal central nervous system (CNS) granulomatous disease, hydrocephalus and stroke. C. neoformans is often suspected in immunodepressed patients, but it can be easily overlooked in otherwise healthy patients. This paper provides a detailed clinical description of a patient without immunosupression who developed multiple simultaneous neurological manifestations after the infection with C. neoformans. PMID:21577360

  4. Central nervous system manifestations of HIV infection in children

    Energy Technology Data Exchange (ETDEWEB)

    George, Reena; Andronikou, Savvas; Plessis, Jaco du; Plessis, Anne-Marie du; Maydell, Arthur [University of Stellenbosch, Department of Radiology, Tygerberg Academic Hospital, Cape Town (South Africa); Toorn, Ronald van [University of Stellenbosch, Department of Paediatrics and Child Health, Tygerberg Academic Hospital, Cape Town (South Africa)

    2009-06-15

    Vertically transmitted HIV infection is a major problem in the developing world due to the poor availability of antiretroviral agents to pregnant women. HIV is a neurotrophic virus and causes devastating neurological insults to the immature brain. The effects of the virus are further compounded by the opportunistic infections and neoplasms that occur as a result of the associated immune suppression. This review focuses on the imaging features of HIV infection and its complications in the central nervous system. (orig.)

  5. Spontaneous electrical activity recorded from the aphid central nervous system

    OpenAIRE

    Nguyen, Dan-Thanh T.; Blacker, Melissa J.; Goodchild, James A.

    2012-01-01

    Whilst many classes of insecticides target the insect central nervous system (CNS), their effects in the CNS of pest aphids have not been demonstrated. In this report, we describe an electrophysiological method for recording spontaneous neuronal activity from the giant willow aphid (Tuberolachnus salignus). Using extracellular recording electrodes and two analysis methods (threshold and template search), spontaneous spike activity was shown to exhibit sensitivity to the neuroexcitatory insect...

  6. Synopsis of volcanic stratigraphy

    Science.gov (United States)

    Hammond, P. E.

    1974-01-01

    Volcanic stratigraphic units are mappable layered units composed of volcanic rocks that are formed on land (subaerially) or under water (subaqueously) by volcanic processes. At least ten different types of volcanic stratigraphic units are recognized. The characteristics for each are discussed briefly and some typical examples are illustrated by diagrams to show their salient features.

  7. Central neural control of the cardiovascular system: current perspectives.

    Science.gov (United States)

    Dampney, Roger A L

    2016-09-01

    This brief review, which is based on a lecture presented at the American Physiological Society Teaching Refresher Course on the Brain and Systems Control as part of the Experimental Biology meeting in 2015, aims to summarize current concepts of the principal mechanisms in the brain that regulate the autonomic outflow to the cardiovascular system. Such cardiovascular regulatory mechanisms do not operate in isolation but are closely coordinated with respiratory and other regulatory mechanisms to maintain homeostasis. The brain regulates the cardiovascular system by two general means: 1) feedforward regulation, often referred to as "central command," and 2) feedback or reflex regulation. In most situations (e.g., during exercise, defensive behavior, sleep, etc.), both of these general mechanisms contribute to overall cardiovascular homeostasis. The review first describes the mechanisms and central circuitry subserving the baroreceptor, chemoreceptor, and other reflexes that work together to regulate an appropriate level of blood pressure and blood oxygenation and then considers the brain mechanisms that defend the body against more complex environmental challenges, using dehydration and cold and heat stress as examples. The last section of the review considers the central mechanisms regulating cardiovascular function associated with different behaviors, with a specific focus on defensive behavior and exercise. PMID:27445275

  8. Radiation induced effects in the developing central nervous system

    International Nuclear Information System (INIS)

    The embryo and the human foetus are particularly sensitive to ionizing radiation and this sensitivity presents various qualitative and quantitative functional changes during intra-uterine development. Apart from radiation induced carcinogenesis, the most serious consequence of prenatal exposure in human beings is severe mental retardation. The principal data on radiation effects on human beings in the development of the central nervous system come form epidemiological studies carried out in individuals exposed in utero during the atomic explosion at Hiroshima and Nagasaki. These observations demonstrate the existence of a time of maximum radiosensitivity between the weeks 8 and 15 of the gestational period, a period in which the proliferation and neuronal migration takes place. Determination of the characteristics of dose-response relationship and the possible existence of a threshold dose of radiation effects on the development of the central nervous system is relevant to radiation protection against low dose radiation and the establishment of dose limits for occupational exposure and the public. Studies were conducted on the generation of nitrous-oxide and its relation with the production of active species of oxygen in brains of exposed rats in utero exposed to doses of up to 1 Gy during their maximum radiosensitivity. The possible role of the mechanism of radiation induced damage in the development of the central nervous system is discussed

  9. The ATLAS Level-1 Central Trigger System 012

    CERN Document Server

    Borrego-Amaral, P; Farthouat, Philippe; Gällnö, P; Haller, J; Maeno, T; Pauly, T; Schuler, G; Spiwoks, R; Torga-Teixeira, R; Wengler, T; Pessoa-Lima, H; De Seixas, J M

    2004-01-01

    The central part of the ATLAS Level-1 trigger system consists of the Central Trigger Processor (CTP), the Local Trigger Processors (LTPs), the Timing, Trigger and Control (TTC) system, and the Read-out Driver Busy (ROD_BUSY) modules. The CTP combines information from calorimeter and muon trigger processors, as well as from other sources and makes the final Level-1 Accept decision (L1A) on the basis of lists of selection criteria, implemented as a trigger menu. Timing and trigger signals are fanned out to about 40 LTPs which inject them into the sub-detector TTC partitions. The LTPs also support stand-alone running and can generate all necessary signals from memory. The TTC partitions fan out the timing and trigger signals to the sub-detector front-end electronics. The ROD_BUSY modules receive busy signals from the front-end electronics and send them to the CTP (via an LTP) to throttle the generation of L1As. An overview of the ATLAS Level-1 Central trigger system will be presented, with emphasis on the design...

  10. Operation of the Upgraded ATLAS Level-1 Central Trigger System

    Science.gov (United States)

    Glatzer, Julian

    2015-12-01

    The ATLAS Level-1 Central Trigger (L1CT) system is a central part of ATLAS data-taking and has undergone a major upgrade for Run 2 of the LHC, in order to cope with the expected increase of instantaneous luminosity of a factor of two with respect to Run 1. The upgraded hardware offers more flexibility in the trigger decisions due to the factor of two increase in the number of trigger inputs and usable trigger channels. It also provides an interface to the new topological trigger system. Operationally - particularly useful for commissioning, calibration and test runs - it allows concurrent running of up to three different subdetector combinations. An overview of the operational software framework of the L1CT system with particular emphasis on the configuration, controls and monitoring aspects is given. The software framework allows a consistent configuration with respect to the ATLAS experiment and the LHC machine, upstream and downstream trigger processors, and the data acquisition system. Trigger and dead-time rates are monitored coherently at all stages of processing and are logged by the online computing system for physics analysis, data quality assurance and operational debugging. In addition, the synchronisation of trigger inputs is watched based on bunch-by-bunch trigger information. Several software tools allow for efficient display of the relevant information in the control room in a way useful for shifters and experts. The design of the framework aims at reliability, flexibility, and robustness of the system and takes into account the operational experience gained during Run 1. The Level-1 Central Trigger was successfully operated with high efficiency during the cosmic-ray, beam-splash and first Run 2 data taking with the full ATLAS detector.

  11. A volcanic activity alert-level system for aviation: review of its development and application in Alaska

    Science.gov (United States)

    2013-01-01

    An alert-level system for communicating volcano hazard information to the aviation industry was devised by the Alaska Volcano Observatory (AVO) during the 1989–1990 eruption of Redoubt Volcano. The system uses a simple, color-coded ranking that focuses on volcanic ash emissions: Green—normal background; Yellow—signs of unrest; Orange—precursory unrest or minor ash eruption; Red—major ash eruption imminent or underway. The color code has been successfully applied on a regional scale in Alaska for a sustained period. During 2002–2011, elevated color codes were assigned by AVO to 13 volcanoes, eight of which erupted; for that decade, one or more Alaskan volcanoes were at Yellow on 67 % of days and at Orange or Red on 12 % of days. As evidence of its utility, the color code system is integrated into procedures of agencies responsible for air-traffic management and aviation meteorology in Alaska. Furthermore, it is endorsed as a key part of globally coordinated protocols established by the International Civil Aviation Organization to provide warnings of ash hazards to aviation worldwide. The color code and accompanying structured message (called a Volcano Observatory Notice for Aviation) comprise an effective early-warning message system according to the United Nations International Strategy for Disaster Reduction. The aviation color code system currently is used in the United States, Russia, New Zealand, Iceland, and partially in the Philippines, Papua New Guinea, and Indonesia. Although there are some barriers to implementation, with continued education and outreach to Volcano Observatories worldwide, greater use of the aviation color code system is achievable.

  12. Central nervous system involvement in systemic lupus erythematosus.

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    This paper deals with the clinical, immunological and pathological data of 5 eases of systemic lupus erythematosus (SLE). Each of the five cases has typical SLE damages on the skin and multiple organs. Among

  13. Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue-Caviahue Volcanic Complex (Argentina)

    Science.gov (United States)

    Chiodini, Giovanni; Cardellini, Carlo; Lamberti, María Clara; Agusto, Mariano; Caselli, Alberto; Liccioli, Caterina; Tamburello, Giancarlo; Tassi, Franco; Vaselli, Orlando; Caliro, Stefano

    2015-10-01

    The north-western sector of Caviahue caldera (Argentina), close to the active volcanic system of Copahue, is characterized by the presence of several hydrothermal sites that host numerous fumarolic emissions, anomalous soil diffuse degassing of CO2 and hot soils. In March 2014, measurements of soil CO2 fluxes in 5 of these sites (namely, Las Máquinas, Las Maquinitas I, Las Maquinitas II, Anfiteatro, and Termas de Copahue) allowed an estimation that ~ 165 t of deeply derived CO2 is daily released. The gas source is likely related to a relatively shallow geothermal reservoir containing a single vapor phase as also suggested by both the geochemical data from the 3 deep wells drilled in the 1980s and gas geoindicators applied to the fumarolic discharges. Gas equilibria within the H-C-O gas system indicate the presence of a large, probably unique, single phase vapor zone at 200-210 °C feeding the hydrothermal manifestations of Las Máquinas, Las Maquinitas I and II and Termas de Copahue. A natural thermal release of 107 MW was computed by using CO2 as a tracer of the original vapor phase. The magmatic signature of the incondensable fumarolic gases, the wide expanse of the hydrothermal areas and the remarkable high amount of gas and heat released by fluid expulsion seem to be compatible with an active magmatic intrusion beneath this portion of the Caviahue caldera.

  14. Gemella morbillorum: an underestimated aetiology of central nervous system infection?

    Science.gov (United States)

    Benedetti, Paolo; Rassu, Mario; Branscombe, Michele; Sefton, Armine; Pellizzer, Giampietro

    2009-12-01

    A case is reported of cerebellar abscess and diffuse cerebritis due to Gemella morbillorum. The clinical course was 'biphasic', developing with an acute meningeal infection followed shortly afterwards by suppuration in the cerebellar and cerebral parenchyma; this pattern seemed to suggest a latent survival of the aetiological agent, probably within the central nervous system (CNS), despite systemic antibiotic therapy. Based upon a review of cases so far described, infections of the CNS caused by G. morbillorum appear to be an emerging reality. PMID:19713361

  15. Centralized database for interconnection system design. [for spacecraft

    Science.gov (United States)

    Billitti, Joseph W.

    1989-01-01

    A database application called DFACS (Database, Forms and Applications for Cabling and Systems) is described. The objective of DFACS is to improve the speed and accuracy of interconnection system information flow during the design and fabrication stages of a project, while simultaneously supporting both the horizontal (end-to-end wiring) and the vertical (wiring by connector) design stratagems used by the Jet Propulsion Laboratory (JPL) project engineering community. The DFACS architecture is centered around a centralized database and program methodology which emulates the manual design process hitherto used at JPL. DFACS has been tested and successfully applied to existing JPL hardware tasks with a resulting reduction in schedule time and costs.

  16. Water System Operator Training for the Central Arizona Project

    OpenAIRE

    Wahlin, Brian; Clemmens, Bert

    2016-01-01

    The Central Arizona Project (CAP) is designed to bring about 1.85 billion cubic meters (1.5 million acre-feet) of Colorado River water per year to Maricopa, Pima, and Pinal counties in Arizona. The CAP canal system is a 540-km (336-mile) long system of conveyance aqueducts, tunnels, pumping plants, and pipelines that is monitored and remotely controlled using Supervisory Control and Data Acquisition (SCADA) software from CAP headquarters in Phoenix, AZ. Because the CAP is crucial to the renew...

  17. Conceptual design of advanced central receiver power system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tracey, T. R.

    1978-09-01

    The design of a 300 MWe tower focus power plant which uses molten salt heat transfer fluids and sensible heat storage is described in detail. The system consists of nine heliostat fields with 7711 heliostats in each. Four cavity receivers are located at the top of a 155-meter tower. Tasks include: (1) review and analysis of preliminary specification; (2) parametric analysis; (3) selection of preferred configuration; (4) commercial plant conceptual design; (5) assessment of commercial-sized advanced central power system; (6) development plan; (7) program plan; (8) reports and data; (9) program management; (10) safety analysis; and (11) material study and test program. (WHK)

  18. Central nervous system frontiers for the use of erythropoietin

    DEFF Research Database (Denmark)

    Olsen, Niels Vidiendal

    2003-01-01

    Recombinant human erythropoietin (r-HuEPO; epoetin alfa) is well established as safe and effective for the treatment of anemia. In addition to the erythropoietic effects of endogenous erythropoietin (EPO), recent evidence suggests that it may elicit a neuroprotective effect in the central nervous...... system (CNS). Preclinical studies have demonstrated the presence of EPO receptors in the brain that are up-regulated under hypoxic or ischemic conditions. Intracerebral and systemic administration of epoetin alfa have been demonstrated to elicit marked neuroprotective effects in multiple preclinical...

  19. Multitasking in academia: Effective combinations of research, education and public outreach illustrated by a volcanic ash warning system

    Science.gov (United States)

    Bye, B. L.; Plag, H.

    2011-12-01

    Science permeates our society. Its role and its perceived importance evolves with time. Scientists today are highly specialized, yet society demands they master a variety of skills requiring not only a number of different competencies but also a broad mindset. Scientists are subjected to a meritocracy in terms of having to produce scientific papers. Peer-reviewed scientific publications used to be sufficient to meet the various laws and regulations with respect to dissemination of scientific results. This has dramatically changed; both expressed directly through public voices (such as in the climate change discourses), but also by politicians and policy makers. In some countries research funding now comes with specific requirements concerning public outreach that go way beyond peer-reviewed publications and presentation at scientific conferences. Science policies encourage multidisciplinary cooperation and scientific questions themselves often cannot be answered without knowledge and information from several scientific areas. Scientists increasingly need to communicate knowledge and results in more general terms as well as educating future generations. A huge challenge lies in developing the knowledge, human capacity and mindset that will allow an individual academician to contribute to education, communicate across scientific fields and sectors in multidisciplinary cross sectoral cooperations and also reach out to the general public while succeeding within the scientific meritocracy. We demonstrate how research, education and communication within and outside academia can effectively be combined through a presentation of the International Airways Volcano Watch that encompasses an operational volcanic ash warning system for the aviation industry. This presentation will show the role of science throughout the information flow, from basic science to the pilots' decision-making. Furthermore, it will illustrate how one can connect specific scientific topics to societal

  20. Diffuse H_{2} emission: a useful geochemical tool to monitor the volcanic activity at El Hierro volcano system

    Science.gov (United States)

    Pérez, Nemesio M.; Melián, Gladys; González-Santana, Judit; Barrancos, José; Padilla, Germán; Rodríguez, Fátima; Padrón, Eleazar; Hernández, Pedro A.

    2016-04-01

    The occurrence of interfering processes affecting reactive gases as CO2 during its ascent from magmatic bodies or hydrothermal systems toward the surface environment hinders the interpretation of their enrichments in the soil atmosphere and fluxes for volcano monitoring purposes (Marini and Gambardella, 2005). These processes include gas scrubbing by ground-waters and interaction with rocks, decarbonatation processes, biogenic production, etc. Within the rest of the soil gases, particularly interest has been addressed to light and highly mobile gases. They offer important advantages for the detection of vertical permeability structures, because their interaction with the surrounding rocks or fluids during the ascent toward the surface is minimum. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas (Giggenbach, 1987). Although H2 can be produced in soils by N2-fixing and fertilizing bacteria, soils are considered nowadays as sinks of molecular hydrogen (Smith-Downey et al., 2006). Because of its chemical and physical characteristics, H2 generated within the crust moves rapidly and escapes to the atmosphere. These characteristics make H2 one of the best geochemical indicators of magmatic and geothermal activity at depth. El Hierro is the youngest and the SW-most of the Canary Islands and the scenario of the last volcanic eruption of the archipelago, a submarine eruption that took place 2 km off the southern coast of the island from October 2011 to March 2012. Since at El Hierro Island there are not any surface geothermal manifestations (fumaroles, etc), we have focused our studies on soil degassing surveys. Here we show the results of soil H2 emission surveys that have been carried out regularly since mid-2012. Soil gas samples were collected in ˜600 sites selected based on their accessibility and geological criteria. Soil gases were sampled at ˜40

  1. The Geothermal Systems along the Watukosek fault system (East Java, Indonesia):The Arjuno-Welirang Volcanic Complex and the Lusi Mud-Eruption

    Science.gov (United States)

    Inguaggiato, Salvatore; Mazzini, Adriano; Vita, Fabio; Sciarra, Alessandra

    2016-04-01

    The Java Island is characterized by an intense volcanic activity with more then 100 active volcanoes. Moreover, this island is also known by the presence of many mud volcanoes and hydrothermal springs. In particular, in the 2006 several sudden hot mud eruptions, with fluids around 100° C, occurred in the NE side of the island resulting in a prominent eruption named Lusi (contraction of Lumpur Sidoarjo) located along the major Watukosek strike-slip fault zone. The Watukosek fault system, strikes from the Arjuno-Welirang volcanic complex, intersects Lusi and extends towards the NE of the Java island. Conversely of the normal mud eruptions (cold fluids emitted in a short time period of few days), the Lusi eruption was characterized by a persistent effusive hot fluids emissions for a long-time period of, so far, nearly a decade. Moreover, the isotopic composition of emitted gases like Helium showed a clear magmatic origin. For this reasons we decided to investigate the near Arjuno-Welirang complex located on the same strike-slip fault. Arjuno-Welirang is a twin strato-volcano system located in the East of Java along the Watukosek fault, at about 25 km SW respect to the Lusi volcano system. It features two main peaks: Arjuno (3339 masl) and Welirang (3156 masl). The last recorded eruptive activity took place in August 1950 from the flanks of Kawah Plupuh and in October 1950 from the NW part of the Gunung Welirang. This strato-volcano is characterized by a S-rich area, with high T-vent fumarole at least up to 220° C (and likely higher), located mainly in the Welirang crater. In addition, several hot springs vent from the flanks of the volcano, indicate the presence of a large hydrothermal system. During July 2015, in the framework of the Lusi Lab project (ERC grant n° 308126), we carried out a geochemical field campaign on the Arjuno-Welirang volcano hydrothermal system area, sampling water and dissolved gases from the thermal and cold springs located on the flanks of

  2. High level extensions to the TRIUMF central control system

    Energy Technology Data Exchange (ETDEWEB)

    Dohan, D.A.; Mouat, M.M.

    1986-10-01

    The TRIUMF central control system ''CCS'' consists of a system of 16-bit minicomputers connected to cyclotron equipment by means of a multi-branch parallel highway CAMAC system. Because these computer ''sources'' are programmed primarily in assembler language, there are difficulties in carrying out complex or precise numerical algorithms. Recently, a limit to the maximum number of sources with access to the CAMAC hardware has been removed and several VAX computers have been added. The configuration has very conveniently allowed independent development of data acquisition and analysis software, and has permitted the implementation of mature accelerator physics software developed elsewhere. The new VAX sources incorporate the use of sophisticated system software, multiple high-level languages, graphics, networking and an independent CAMAC highway. A separate serial CAMAC highway supports cyclotron development without compromising the on-line duties of the existing central control system. This paper describes the new configuration and the implementation of the data acquisition and analysis software.

  3. Salt movements within the Central European basin system

    Energy Technology Data Exchange (ETDEWEB)

    Maystrenko, Yuriy; Bayer, Ulf; Scheck-Wenderoth [GeoForschungsZentrum (GFZ), Potsdam (Germany); Littke, Ralf [RWTH Aachen (Germany). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle

    2010-04-15

    Evolution of salt structures in relation to tectonic events within central part of the Central European Basin System is described by summarizing results which have been obtained and published in frame of the research project DFG-SPP 1135. These results illustrate main phases of salt tectonics within the basin system from the Triassic to present day. During the Buntsandstein and Muschelkalk, extension triggered raft tectonics and salt movements within the Ems Trough, the Glueckstadt and the Horn Grabens. The next phase of salt movements occurred in response to a Middle-Late Keuper regional extensional event which was strongest within the Triassic depocenters of the Central European Basin System, such as the Horn Graben, the Glueckstadt Graben, the Ems and the Rheinsberg Troughs. Regional erosion truncated the study area during the Late Jurassic-Early Cretaceous time. The magnitude of Late Jurassic-Early Cretaceous erosion is declining towards southern margin of the basin system where a dextral transtensional regime was established in the Lower Saxony Basin and neighboring areas during the Late Jurassic-Early Cretaceous. The late Early Cretaceous-early Late Cretaceous is characterized by a relative tectonic quiescence without strong salt movements. The Late Cretaceous-Early Cenozoic inversion provocated renewed salt movements, causing the thick-skinned salt tectonics along the Elbe Fault System and the thin-skinned character of salt movements towards the north from the area of strain localisation. Post-inversion Cenozoic subsidence was accompanied by salt movements, related either to diapiric rise due to regional shortening and/or to local almost E-W directed extension. (orig.)

  4. Geology and petrology of the Vulsinian volcanic area (Latium, Italy)

    NARCIS (Netherlands)

    Varekamp, J.C.

    1979-01-01

    The Vulsinian volcanic area is situated in Latium, west central Italy. This quarternary volcanic complex consists of a series of layered tuffs, lava flows, ignimbrites, and many small cinder and ash cones. A steep central edifice is lacking due to the relatively large amount of pyroclastic deposits.

  5. Dynamics and control of multibody systems in central gravity

    Science.gov (United States)

    Sanyal, Amit K.

    This dissertation studies the dynamics and control of multibody systems, and their numerical simulation, in a central gravitational field. Initially, the dynamics of multibody systems moving in a plane in a central gravity is studied. There is a cyclic orbital coordinate, and the corresponding conjugate momentum is conserved. The dynamics is reduced to eliminate this cyclic variable. A general development for analyzing stability of relative equilibria of the full dynamics, corresponding to equilibria of the reduced dynamics, is obtained. This is applied to some examples of multibody spacecraft in planar motion. A control scheme, based on averaging theory, is developed for orbit transfer from one relative equilibrium to another. This scheme is applied to a planar dumbbell-shaped rigid body in central gravity. The dynamics of such systems in three-dimensional motion also has a cyclic coordinate, and the associated conjugate momentum is conserved. The dynamics is reduced to eliminate this degree of freedom. Stability analysis of the relative equilibria of a rigid dumbbell-shaped body is carried out. Potential shaping with attitude feedback is used to stabilize the unstable relative equilibria of the dumbbell body. For numerical simulations of the dynamics of free and controlled multibody systems in central gravity, numerical integration algorithms obtained from discrete variational mechanics are used. These algorithms exactly preserve the symplectic form and conserved momenta of such systems. They also nearly preserve the total energy of conservative systems over long simulation times. These properties are usually not present in other numerical integration algorithms. Variational integration algorithms for the full and reduced dynamics of multibody systems in a potential field are obtained, and applied to the specific examples treated in this dissertation. Comparison with a standard Runge-Kutta fourth order integrator, for an example problem, shows the better

  6. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2016-01-01

    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  7. Refining the Ciona intestinalis model of central nervous system regeneration.

    Directory of Open Access Journals (Sweden)

    Carl Dahlberg

    Full Text Available BACKGROUND: New, practical models of central nervous system regeneration are required and should provide molecular tools and resources. We focus here on the tunicate Ciona intestinalis, which has the capacity to regenerate nerves and a complete adult central nervous system, a capacity unusual in the chordate phylum. We investigated the timing and sequence of events during nervous system regeneration in this organism. METHODOLOGY/PRINCIPAL FINDINGS: We developed techniques for reproducible ablations and for imaging live cellular events in tissue explants. Based on live observations of more than 100 regenerating animals, we subdivided the regeneration process into four stages. Regeneration was functional, as shown by the sequential recovery of reflexes that established new criteria for defining regeneration rates. We used transgenic animals and labeled nucleotide analogs to describe in detail the early cellular events at the tip of the regenerating nerves and the first appearance of the new adult ganglion anlage. CONCLUSIONS/SIGNIFICANCE: The rate of regeneration was found to be negatively correlated with adult size. New neural structures were derived from the anterior and posterior nerve endings. A blastemal structure was implicated in the formation of new neural cells. This work demonstrates that Ciona intestinalis is as a useful system for studies on regeneration of the brain, brain-associated organs and nerves.

  8. Genesis and Eruptive Dynamics of the Garnet-Bearing Rhyolites from the Ramadas Volcanic Centre (Altiplano-Puna Plateau, Central Andes, Argentina).

    Science.gov (United States)

    De Astis, G.; Baez, W.; Bardelli, L.; Becchio, R.; Giordano, G.; Lucci, F.; Rossetti, F.; Viramonte, J. G.

    2015-12-01

    Ramadas volcanic centre (6.6 Ma) is a monogenetic calderic depression, now largely obliterated, almost coeval with the Late Miocene outbreak of highly explosive silicic activity in the Altiplano-Puna plateau. Ramadas erupted a rather complex suite of garnet-bearing, rhyolitic pyroclastic rocks, dominated by a >35 km3 fall deposit and preceded by the emplacement of a lag breccia containing abundant metasedimentary lithics and garnet-tourmaline leucogranites. During the waning stage of the eruption, small volume phreatomagmatic deposits formed a small tuff-ring, followed by a lava coulée emplacement. Volcanological data together with textural features of typical tube pumice evidence a volatiles-rich, plinian eruption. Petrographic and textural studies on juveniles confirm the presence of euhedral garnet as dominant phase and identify micrometric metaigneous fragments (Qtz+Bt+Kfs+Mt+Tur). BSE imaging and microprobe analyses on glasses, garnets and accessory mineral phases (zircon and monazite) provide further data to understand the genesis and eruptive conditions of these atypical rhyolites, geochemically different from those outcropping in the same region. Garnets display a homogeneous, unzoned almandine-spessartine composition (Alm72-71Sps24-23Pyr0-1Grs4-3) and are contained in a glassy rhyolitic magma with peraluminous character, HREE depleted and relative LREE enriched. It's known that primary igneous garnets are rare and can only develop under restricted conditions. Additionally, the presence of Zr and Mnz is associated with both magmatic and high-T metamorphic processes. Although more data need to be collected, our study and preliminary modelling point to the occurrence of thermal metamorphism shifting to partial melting of Fe-MnO-rich metapelitic rocks (or even re-melting of older acid volcanics), with final extraction of volatiles-rich rhyolitic melts, able to produce a plinian eruption. Here, Alm-Sps garnet could represent the peritectic product of the

  9. On water in volcanic clouds

    Science.gov (United States)

    Durant, Adam J.

    2007-12-01

    Volcanic clouds and tephra fallout present a hazard to aviation, human and animal health (direct inhalation or ingestion, contamination of water supplies), and infrastructure (building collapse, burial of roads and railways, agriculture, abrasive and chemical effects on machinery). Understanding sedimentation processes is a fundamental component in the prediction of volcanic cloud lifetime and fallout at the ground, essential in the mitigation of these hazards. The majority of classical volcanic ash transport and dispersion models (VATDM) are based solely on fluid dynamics. The non-agreement between VATDM and observed regional-scale tephra deposit characteristics is especially obvious at large distances from the source volcano. In meteorology, the processes of hydrometeor nucleation, growth and collection have been long-established as playing a central role in sedimentation and precipitation. Taking this as motivation, the hypothesis that hydrometeor formation drives sedimentation from volcanic clouds was tested. The research objectives of this dissertation are: (1) To determine the effectiveness of tephra particles in the catalysis of the liquid water to ice phase transformation, with application to ice hydrometeor formation in volcanic clouds. (2) To determine the sedimentological characteristics of distal (100s km) tephra fallout from recent volcanic clouds. (3) To assess particle fallout rates from recent volcanic clouds in the context of observed deposit characteristics. (4) To assess the implications of hydrometeor formation on the enhancement of volcanic sedimentation and the potential for cloud destabilization from volcanic hydrometeor sublimation. Dissertation Overview. The following chapters present the analysis, results and conclusions of heterogeneous ice nucleation experiments and sedimentological characterization of several recent tephra deposits. The dissertation is organized in three chapters, each prepared in journal article format. In Chapter 1

  10. Open system degassing, bubble rise and flow dynamics within volcanic conduits- an experimental approach

    Science.gov (United States)

    Pioli, L.; Azzopardi, B. J.; Bonadonna, C.; Marchetti, E.; Ripepe, M.

    2009-12-01

    Open conduit basaltic volcanoes are characterized by frequent eruptions, usually consisting in mild Strombolian and Hawaiian explosions, alternating years to months of quiescence periods, with degassing activity from the central conduit. Recent improvements of thermal, video, radar and acoustic monitoring techniques have provided new powerful tools for the study of degassing processes and made available geophysical and geochemical datasets for many central volcanoes, such as Stromboli, Etna (Italy), Kilauea (Hawaii), Villarrica (Chile). These studies revealed that degassing is an unsteady, often pulsatory process, characterized by fluctuations in both intensity and composition of the emitted gases. Unambiguous interpretation of monitoring data of surface activity in terms of conduit dynamics and flow processes is, however, not possible, due to partial knowledge of the physical processes controlling the dynamics of two-phase flows in magmas. We performed a series of experiments to gain further insights on the dynamics of the gas-bubble rise in magmas within a cylindrical conduit, their ability to segregate and coalesce and the effect of these processes on the degassing dynamics. The experiments consisted in generating fluxes at variable intensities of air through stagnant water or glucose syrup in a bubble column apparatus 6.5 m high and with a diameter of 24 cm diameter. Glucose syrup and water are Newtonian liquids with viscosity ranging from 2.4 to 204.0 Pa*s and from 1.7 to 0.2 10 -3 Pa*s respectively, depending on temperature. Air was inserted at the base of the column through a variable number (1 to 25) of 5mm-diameter nozzles reaching surficial gas velocities of up to 0.5 m/s. The activity of the bubble column was monitored through temperature, pressure, void fraction and acoustic measurements and filmed by a high-speed camera with maximum resolution of 800x600 pixels. Pressure fluctuations, vesicularity and acoustic signal were then analyzed and correlated

  11. Records of climatic changes and volcanic events in an ice core from Central Dronning Maud Land (East Antarctica) during the past century

    Indian Academy of Sciences (India)

    V N Nijampurkar; D K Rao; H B Clausen; M K Kaul; A Chaturvedi

    2002-03-01

    The depth profiles of electrical conductance, 18O, 210Pb and cosmogenic radio isotopes 10Be and 36Cl have been measured in a 30 m ice core from east Antarctica near the Indian station, Dakshin Gangotri. Using 210Pb and 18O, the mean annual accumulation rates have been calculated to be 20 and 21 cm of ice equivalent per year during the past ∼150 years. Using these acumulation rates, the volcanic event that occurred in 1815 AD, has been identified based on electrical conductance measurements. Based on 18O measurements, the mean annual surface air temperatures (MASAT) data observed during the last 150 years indicates that the beginning of the 19th century was cooler by about 2°C than the recent past and the middle of 18th century. The fallout of cosmogenic radio isotope 10Be compares reasonably well with those obtained on other stations (73° S to 90°S) from Antarctica and higher latitudes beyond 77°N. The fallout of 36Cl calculated based on the present work agrees well with the mean global production rate estimated earlier by Lal and Peters (1967) The bomb pulse of 36Cl observed in Greenland is not observed in the present studies a result which is puzzling and needs to be studied on neighbouring ice cores from the same region.

  12. Volcano-Hydrothermal Systems of the Central and Northern Kuril Island Arc - a Review

    Science.gov (United States)

    Kalacheva, E.; Taran, Y.; Voloshina, E.; Ptashinsky, L.

    2015-12-01

    More than 20 active volcanoes with historical eruptions are known on 17 islands composing the Central and Northern part of the Kurilian Arc. Six islands - Paramushir, Shiashkotan, Rasshua, Ushishir, Ketoy and Simushir - are characterized by hydrothermal activity, complementary to the fumarolic activity in their craters. There are several types of volcano-hydrothermal systems on the islands. At Paramushir, Shiashkotan and Ketoy the thermal manifestations are acidic to ultra-acidic water discharges associated with hydrothermal aquifers inside volcano edifices and formed as the result of the absorption of magmatic gases by ground waters. A closest known analogue of such activity is Satsuma-Iwojima volcano-island at the Ryukyu Arc. Another type of hydrothermal activity are wide spread coastal hot springs (Shiashkotan, Rasshua), situated as a rule within tide zones and formed by mixing of the heated seawater with cold groundwater or, in opposite, by mixing of the steam- or conductively heated groundwater with seawater. This type of thermal manifestation is similar to that reported for other volcanic islands of the world (Satsuma Iwojima, Monserrat, Ischia, Socorro). Ushishir volcano-hydrothermal system is formed by the absorption of magmatic gases by seawater. Only Ketoy Island hosts a permanent acidic crater lake. At Ebeko volcano (Paramushir) rapidly disappearing small acidic lakes (formed after phreatic eruptions) have been reported. The main hydrothermal manifestation of Simushir is the Zavaritsky caldera lake with numerous coastal thermal springs and weak steam vents. The last time measured temperatures of fumaroles at the islands are: >500ºC at Pallas Peak (Ketoy), 480ºC at Kuntamintar volcano (Shiashkotan), variable and fast changing temperatures from 120º C to 500ºC at Ebeko volcano (Paramushir), 150ºC in the Rasshua crater, and > 300ºC in the Chirpoy crater (Black Brothers islands). The magmatic and rock-forming solute output by the Kurilian volcano

  13. Operation of the Upgraded ATLAS Level-1 Central Trigger System

    CERN Document Server

    Glatzer, Julian Maximilian Volker; The ATLAS collaboration

    2015-01-01

    The ATLAS Level-1 Central Trigger (L1CT) system is a central part of ATLAS data-taking and has undergone a major upgrade for Run 2 of the LHC, in order to cope with the expected increase of instantaneous luminosity of a factor of 2 with respect to Run 1. The upgraded hardware offers more flexibility in the trigger decisions due to the double amount of trigger inputs and usable trigger channels. It also provides an interface to the new topological trigger system. Operationally - particularly useful for commissioning, calibration and test runs - it allows concurrent running of up to 3 different subdetector combinations. An overview of the operational software framework of the L1CT system with particular emphasis of the configuration, controls and monitoring aspects is given. The software framework allows a consistent configuration with respect to the ATLAS experiment and the LHC machine, upstream and downstream trigger processors, and the data acquisition. Trigger and dead-time rates are monitored coherently at...

  14. Functional roles of neuropeptides in the insect central nervous system

    Science.gov (United States)

    Nässel, D. R.

    With the completion of the Drosophila genome sequencing project we can begin to appreciate the extent of the complexity in the components involved in signal transfer and modulation in the nervous system of an animal with reasonably complex behavior. Of all the different classes of signaling substances utilized by the nervous system, the neuropeptides are the most diverse structurally and functionally. Thus peptidergic mechanisms of action in the central nervous system need to be analyzed in the context of the neuronal circuits in which they act and generalized traits cannot be established. By taking advantage of Drosophila molecular genetics and the presence of identifiable neurons, it has been possible to interfere with peptidergic signaling in small populations of central neurons and monitor the consequences on behavior. These studies and experiments on other insects with large identifiable neurons, permitting cellular analysis of signaling mechanisms, have outlined important principles for temporal and spatial action of neuropeptides in outputs of the circadian clock and in orchestrating molting behavior. Considering the large number of neuropeptides available in each insect species and their diverse distribution patterns, it is to be expected that different neuropeptides play roles in most aspects of insect physiology and behavior.

  15. Operation of the Upgraded ATLAS Level-1 Central Trigger System

    CERN Document Server

    Glatzer, Julian Maximilian Volker; The ATLAS collaboration

    2015-01-01

    The ATLAS Level-1 Central Trigger (L1CT) system is a central part of ATLAS data-taking and has undergone a major upgrade for Run 2 of the LHC, in order to cope with the expected increase of instantaneous luminosity of a factor of 2 with respect to Run 1. The upgraded hardware offers more flexibility in the trigger decisions due to the double amount of trigger inputs and usable trigger channels. It also provides an interface to the new topological trigger system. Operationally - particularly useful for commissioning, calibration and test runs - it allows concurrent running of up to 3 different sub-detector combinations. In this contribution, we give an overview of the operational software framework of the L1CT system with particular emphasis of the configuration, controls and monitoring aspects. The software framework allows a consistent configuration with respect to the ATLAS experiment and the LHC machine, upstream and downstream trigger processors, and the data acquisition. Trigger and dead-time rates are m...

  16. Model adaptation in a central controller for a sewer system

    Science.gov (United States)

    van Nooijen, Ronald; Kolechkina, Alla; Mol, Bart

    2013-04-01

    For small sewer systems that combine foul water and storm water sewer functions in flat terrain, central control of the sewer system may have problems during dry weather. These systems are a combination of local gravity flow networks connected by pumps. Under those conditions the level in the wet well (local storage at the pumping station) should be kept below the entrance pipe but above the top of the intake of the pump. The pumps are dimensioned to cope with the combined flow of foul water and precipitation run off so their capacity is relatively large when compared wityh the volume available in the wet well. Under local control this is not a major problem because the effective controller time step is very short. For central control the control time step can become a problem. Especially when there is uncertainty about the relation between level and volume in the wet well. In this paper we describe a way to dynamically adapt the level to volume relation based on dry weather behaviour. This is important because a better estimate of this volume will reduce the number of on/off cycles for the pumps. It will also allow detection and correction for changes in pump performance due to aging.

  17. Breast cancer metastasis to the central nervous system.

    Science.gov (United States)

    Weil, Robert J; Palmieri, Diane C; Bronder, Julie L; Stark, Andreas M; Steeg, Patricia S

    2005-10-01

    Clinically symptomatic metastases to the central nervous system (CNS) occur in approximately 10 to 15% of patients with metastatic beast cancer. CNS metastases are traditionally viewed as a late complication of systemic disease, for which few effective treatment options exist. Recently, patients with Her-2-positive breast tumors who were treated with trastuzumab have been reported to develop CNS metastases at higher rates, often while responding favorably to treatment. The blood:brain barrier and the unique brain microenvironment are hypothesized to promote distinct molecular features in CNS metastases that may require tailored therapeutic approaches. New research approaches using cell lines that reliably and preferentially metastasize in vivo to the brain have been reported. Using such model systems, as well as in vitro analogs of blood-brain barrier penetration and tissue-based studies, new molecular leads into this disease are unfolding. PMID:16192626

  18. Multifaceted interactions between adaptive immunity and the central nervous system.

    Science.gov (United States)

    Kipnis, Jonathan

    2016-08-19

    Neuroimmunologists seek to understand the interactions between the central nervous system (CNS) and the immune system, both under homeostatic conditions and in diseases. Unanswered questions include those relating to the diversity and specificity of the meningeal T cell repertoire; the routes taken by immune cells that patrol the meninges under healthy conditions and invade the parenchyma during pathology; the opposing effects (beneficial or detrimental) of these cells on CNS function; the role of immune cells after CNS injury; and the evolutionary link between the two systems, resulting in their tight interaction and interdependence. This Review summarizes the current standing of and challenging questions related to interactions between adaptive immunity and the CNS and considers the possible directions in which these aspects of neuroimmunology will be heading over the next decade. PMID:27540163

  19. Tuberculosis of the central nervous system: overview of neuroradiological findings

    Energy Technology Data Exchange (ETDEWEB)

    Bernaerts, A.; Vanhoenacker, F.M. [Department of Radiology, University of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium); Department of Radiology, AZ St-Maarten, Campus Duffel, Rooienberg 25, 2750 Duffel (Belgium); Parizel, P.M.; Goethem, J.W.M. van; De Roeck, J.; De Schepper, A.M. [Department of Radiology, University of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium); Altena, R. van [Tuberculosecentrum Beatrixoord, Dilgtweg 5, 9751 ND Haren (Netherlands); Laridon, A. [Department of Pediatrics, University of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium); Coeman, V. [Department of Radiology, AZ St-Jan, Ruddershove 10, 8000 Brugge (Belgium)

    2003-08-01

    This article presents the range of manifestations of tuberculosis (TB) of the craniospinal axis. Central nervous system (CNS) infection with Mycobacterium tuberculosis occurs either in a diffuse form as basal exudative leptomeningitis or in a localized form as tuberculoma, abscess, or cerebritis. In addition to an extensive review of computed tomography and magnetic resonance features, the pathogenesis and the relevant clinical setting are discussed. Modern imaging is a cornerstone in the early diagnosis of CNS tuberculosis and may prevent unnecessary morbidity and mortality. Contrast-enhanced MR imaging is generally considered as the modality of choice in the detection and assessment of CNS tuberculosis. (orig.)

  20. Tuberculosis of the central nervous system: overview of neuroradiological findings

    International Nuclear Information System (INIS)

    This article presents the range of manifestations of tuberculosis (TB) of the craniospinal axis. Central nervous system (CNS) infection with Mycobacterium tuberculosis occurs either in a diffuse form as basal exudative leptomeningitis or in a localized form as tuberculoma, abscess, or cerebritis. In addition to an extensive review of computed tomography and magnetic resonance features, the pathogenesis and the relevant clinical setting are discussed. Modern imaging is a cornerstone in the early diagnosis of CNS tuberculosis and may prevent unnecessary morbidity and mortality. Contrast-enhanced MR imaging is generally considered as the modality of choice in the detection and assessment of CNS tuberculosis. (orig.)

  1. Fulminant Demyelinating Diseases of the Central Nervous System.

    Science.gov (United States)

    Bevan, Carolyn J; Cree, Bruce A

    2015-12-01

    Fulminant demyelinating diseases of the central nervous system include acute disseminated encephalomyelitis, the related acute hemorrhagic leukoencephalitis, multiple sclerosis variants, neuromyelitis optica spectrum disorders, and idiopathic transverse myelitis. These syndromes are often managed with similar acute treatments including high-dose corticosteroids and plasmapheresis; however, long-term management varies. Although the prognosis of fulminant demyelinating disease was historically poor, outcomes today may be improved due to earlier diagnosis, rapid implementation of anti-inflammatory therapies such as high-dose corticosteroids and plasmapheresis, and improved supportive care. PMID:26595866

  2. Hypopituitarism as unusual sequelae to central nervous system tuberculosis

    Directory of Open Access Journals (Sweden)

    S Mageshkumar

    2011-01-01

    Full Text Available Neurological tuberculosis can very rarely involve the hypophysis cerebri. We report a case of an eighteen year old female who presented with five months duration of generalised apathy, secondary amenorrhea and weight gain. She was on irregular treatment for tuberculosis of the central nervous system for the last five months. Neuroimaging revealed sellar and suprasellar tuberculomas and communicating hydrocephalus requiring emergency decompression. Endocrinological investigation showed hypopituitarism manifesting as pituitary hypothyroidism, hypocortisolism, hypogonadotropic hypogonadism, and hyperprolactinemia. Restarting anti-tuberculosis treatment, hormone replacement therapy, and a ventriculo-peritoneal shunt surgery led to remarkable improvement in the general condition of the patient.

  3. Masquerade Syndrome of Multicentre Primary Central Nervous System Lymphoma

    Directory of Open Access Journals (Sweden)

    Silvana Guerriero

    2011-01-01

    Full Text Available Purpose. In Italy we say that the most unlucky things can happen to physicians when they get sick, despite the attention of colleagues. To confirm this rumor, we report the sad story of a surgeon with bilateral vitreitis and glaucoma unresponsive to traditional therapies. Methods/Design. Case report. Results. After one year of steroidal and immunosuppressive therapy, a vitrectomy, and a trabeculectomy for unresponsive bilateral vitreitis and glaucoma, MRI showed a multicentre primary central nervous system lymphoma, which was the underlying cause of the masquerade syndrome. Conclusions. All ophthalmologists and clinicians must be aware of masquerade syndromes, in order to avoid delays in diagnosis.

  4. On the Role of Climate Forcing by Volcanic Sulphate and Volcanic Ash

    OpenAIRE

    Baerbel Langmann

    2014-01-01

    There is overall agreement that volcanic sulphate aerosols in the stratosphere can reduce solar radiation reaching the earth’s surface for years, thereby reducing surface temperatures, affecting global circulation patterns and generally the global climate system. However, the response of the climate system after large volcanic eruptions is not fully understood and global climate models have difficulties to reproduce the observed variability of the earth system after large volcanic eruptions u...

  5. Central nervous system involvement in systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Cranial computed tomography scans were performed on 47 patients with systemic lupus erythematosus (SLE). Abnormal findings in the computed tomograms (CT) were observed in 17 patients (36.2%). Cerebral atrophy was the most common feature (eight cases), followed by abnormal high density areas (five cases), abnormal low density areas (three cases), sulcal enlargement (two cases), intracranial hemorrhage (one case) and others (two cases). The abnormal cranial CT group of SLE was associated with a significantly higher incidence of urinary casts and of thrombocytopenia. In particular, the frequency of urinary casts was greater in the group with cerebral atrophy than in the group with normal CT findings, and there was a higher incidence of alopecia, leukopenia and thrombocytopenia in the group with intracranial calcifications. Neuropsychiatric involvements were noted in 70.6% of patients with CT abnormalities, but neuropsychiatric features (20.7%) and electroencephalographic abnormalities (44.8%) were also observed in patients with normal CT findings. The age at onset of SLE, the mean duration of the disease and the survival rate were not significantly different between the groups with and without CT abnormalities, but the mortality rate was significantly greater in the group with CT abnormalities, especially among those with brain atrophy. Concerning the relationship between the findings of cranial CT and corticosteroid treatment, there was no significant difference in either the total dose or the mean duration of prednisolone therapy. Although SLE patients with cerebral atrophy were taking a larger maintenance dose of corticosteroids, the differences were not statistically significant. (J.P.N.)

  6. [Malignant lymphoma in the central nervous system: overview].

    Science.gov (United States)

    Namekawa, Michito

    2014-08-01

    Malignant lymphoma can affect the central nervous system (CNS) in three different ways: as a consequence (relapse or invasion) of systemic lymphoma, as a primary CNS lymphoma (PCNSL) without systemic involvement, and through intravascular lymphomatosis (IVL). It is essential to distinguish PCNSL from the others, since the therapeutic strategy for treating this disease differs. FDG-PET/CT fusion imagery is a powerful tool for detecting systemic lesions. If a marked elevation of lactate dehydrogenase and the soluble IL-2 receptor suggests IVL, a random skin biopsy can permit a differential diagnosis. It is not certain why PCNSL occurs solely in the CNS, where there is no lymphatic system. The special environment, so-called "sanctuary site", where is free from attack of the immune system and penetration of chemotherapeutic agents by blood-brain barrier is deeply related to malignant transformation. The prognoses for patients with CNS invasion of systemic lymphoma and those with PCNSL remain bleak in the post-rituximab era. Over half of the patients who received high-dose methotrexate will subsequently relapse. Therefore, novel therapeutic strategies are earnestly sought. PMID:25082313

  7. Operating The Central Process Systems At Glenn Research Center

    Science.gov (United States)

    Weiler, Carly P.

    2004-01-01

    As a research facility, the Glenn Research Center (GRC) trusts and expects all the systems, controlling their facilities to run properly and efficiently in order for their research and operations to occur proficiently and on time. While there are many systems necessary for the operations at GRC, one of those most vital systems is the Central Process Systems (CPS). The CPS controls operations used by GRC's wind tunnels, propulsion systems lab, engine components research lab, and compressor, turbine and combustor test cells. Used widely throughout the lab, it operates equipment such as exhausters, chillers, cooling towers, compressors, dehydrators, and other such equipment. Through parameters such as pressure, temperature, speed, flow, etc., it performs its primary operations on the major systems of Electrical Dispatch (ED), Central Air Dispatch (CAD), Central Air Equipment Building (CAEB), and Engine Research Building (ERB). In order for the CPS to continue its operations at Glenn, a new contract must be awarded. Consequently, one of my primary responsibilities was assisting the Source Evaluation Board (SEB) with the process of awarding the recertification contract of the CPS. The job of the SEB was to evaluate the proposals of the contract bidders and then to present their findings to the Source Selecting Official (SSO). Before the evaluations began, the Center Director established the level of the competition. For this contract, the competition was limited to those companies classified as a small, disadvantaged business. After an industry briefing that explained to qualified companies the CPS and type of work required, each of the interested companies then submitted proposals addressing three components: Mission Suitability, Cost, and Past Performance. These proposals were based off the Statement of Work (SOW) written by the SEB. After companies submitted their proposals, the SEB reviewed all three components and then presented their results to the SSO. While the

  8. Multistation alarm system for eruptive activity based on the automatic classification of volcanic tremor: specifications and performance

    Science.gov (United States)

    Langer, Horst; Falsaperla, Susanna; Messina, Alfio; Spampinato, Salvatore

    2015-04-01

    With over fifty eruptive episodes (Strombolian activity, lava fountains, and lava flows) between 2006 and 2013, Mt Etna, Italy, underscored its role as the most active volcano in Europe. Seven paroxysmal lava fountains at the South East Crater occurred in 2007-2008 and 46 at the New South East Crater between 2011 and 2013. Month-lasting lava emissions affected the upper eastern flank of the volcano in 2006 and 2008-2009. On this background, effective monitoring and forecast of volcanic phenomena are a first order issue for their potential socio-economic impact in a densely populated region like the town of Catania and its surroundings. For example, explosive activity has often formed thick ash clouds with widespread tephra fall able to disrupt the air traffic, as well as to cause severe problems at infrastructures, such as highways and roads. For timely information on changes in the state of the volcano and possible onset of dangerous eruptive phenomena, the analysis of the continuous background seismic signal, the so-called volcanic tremor, turned out of paramount importance. Changes in the state of the volcano as well as in its eruptive style are usually concurrent with variations of the spectral characteristics (amplitude and frequency content) of tremor. The huge amount of digital data continuously acquired by INGV's broadband seismic stations every day makes a manual analysis difficult, and techniques of automatic classification of the tremor signal are therefore applied. The application of unsupervised classification techniques to the tremor data revealed significant changes well before the onset of the eruptive episodes. This evidence led to the development of specific software packages related to real-time processing of the tremor data. The operational characteristics of these tools - fail-safe, robustness with respect to noise and data outages, as well as computational efficiency - allowed the identification of criteria for automatic alarm flagging. The

  9. U-Pb SHRIMP and Sm-Nd geochronology of the Silvânia Volcanics and Jurubatuba Granite: juvenile Paleoproterozoic crust in the basement of the Neoproterozoic Brasília Belt, Goiás, central Brazil

    Directory of Open Access Journals (Sweden)

    FISCHEL DANIELLE P.

    2001-01-01

    Full Text Available U-Pb SHRIMP and Sm-Nd isotopic ages were determined for felsic metavolcanic rocks from the Silvânia Sequence and Jurubatuba Granite in the central part of the Brasília Belt. Zircon grains from a metavolcanic sample yielded 2115 ± 23 Ma and from the granite yielded 2089 ± 14 Ma, interpreted as crystallization ages of these rocks. Six metavolcanic samples of the Silvânia Sequence yielded a six-point whole-rock Sm-Nd isochron indicating a crystallization age of 2262 ± 110 Ma and positive epsilonNd(T = +3.0 interpreted as a juvenile magmatic event. Nd isotopic analyses on samples from the Jurubatuba Granite have Paleoproterozoic T DM model ages between 2.30 and 2.42 Ga and epsilonNd(T values vary between -0.22 and -0.58. The oldest T DM value refers to a sedimentary xenolith in the granite. These results suggest crystallization ages of Silvânia volcanics and Jurubatuba Granite are the first evidence of a ca. 2.14-2.08 juvenile magmatic event in the basement of the central part of the Brasília Belt that implies the presence of arc/suture hidden in reworked basement of the Brasília Belt.

  10. Longitudinal analysis of hearing loss in a case of hemosiderosis of the central nervous system.

    NARCIS (Netherlands)

    Weekamp, H.; Huygen, P.L.M.; Merx, J.L.; Kremer, H.P.H.; Cremers, C.W.R.J.; Longridge, N.S.

    2003-01-01

    OBJECTIVE: To describe cochleovestibular aspects of superficial hemosiderosis of the central nervous system. BACKGROUND: Superficial hemosiderosis of the central nervous system is a rare disease in which cochleovestibular impairment, cerebellar ataxia, and myelopathy are the most frequent signs. Chr

  11. Volcano deformation in central Main Ethiopian Rift system (Aluto Volcano) inferred from continuous GPS and dynamic gravity observations

    Science.gov (United States)

    Birhanu, Yelebe; Biggs, Juliet; Gottsmann, Joachim; Lewi, Elias; Lloyd, Ryan; Bekele, Berhanu

    2016-04-01

    Silicic volcanic centres in the rift systems frequently experience unrest indicating long-term activity in the underlying magmatic system, but it is difficult to distinguish the contributions of hydrothermal fluids, magma or gasses. Aluto volcano which is located in the central MER system is situated between the Lakes Ziway and Langano in the north and south respectively. Continuous GPS installed from April 2013 to October 2015 shows subsidence initially, with the largest subsidence observed in the eastern part of the caldera (2 cm/yr). InSAR observations from TerraSAR-X show a radially-symmetric pattern of long-term subsidence. Dynamic gravity surveys carried out in October 2014 and 2015 showed that there is a net mass loss in the western and central part of the caldera and mass gain in the eastern and southern part of the caldera, with a sharp gradient between the two. This complex spatial pattern of gravity change is significantly different to the simple pattern of deformation indicating multiple sources of pressure and mass change exist within the caldera. We explain the ratio of gravity to height change (dg/dh) throughout the volcano by considering cooling and crystallisation of magma body, draining and precipitation of hydrothermal fluids and changes in the water table and lake levels. Keywords: volcano deformation, dynamic gravity, continental rift

  12. Chemistry and origin of the Mayo Kila sapphires, NW region Cameroon (Central Africa): Their possible relationship with the Cameroon volcanic line

    Science.gov (United States)

    Paul Mbih, Kemeng; Meffre, Sebastien; Yongue, Rose Fouateu; Kanouo, Nguo Sylvestre; Jay, Thomson

    2016-06-01

    Mineralogical, chemical and geochronological studies constrained the origin of sapphires from Mayo Kila, Northwest Cameroon. The sapphires are mostly blue, with sizes ranging from 2 to 5 mm. The pale blue grains are transparent, whereas, other corundums are transparent to translucent and/or opaque. The sapphires are dominantly euhedral to sub-hedral with few polished lustrous grains, acquired features during moderate to short distance transport from a proximal source rock. Solid inclusions are limited to rutile and zircon. Trace element analysis of sapphires shows significant concentration (in ppm) in some elements: Fe (2208-14,473), Ti (82-1783), Ga (77-512), Mg (0.9-264.9), Cr (b.d.l -168) and V (1.3-82). The other elements (e.g. Sn, Nb, Ta, Th, Zr, Ni, Ce) are generally below 10 ppm. The calculated ratios for some of the selected elements show an extreme variation: Fe/Mg (43-3043), Fe/Ti (2-76), Ti/Mg (1-328), and Ga/Mg (0.4-363). They are dominantly corundum crystallized in alkaline magma (s) with few from metamorphic source (s). Trace elemental features with Hf (13,354-26,238 ppm), Th (4018-45,584 ppm) and U (7825-17,175 ppm), and Th/U (0.39-2.65) found in zircon inclusions are compatible with quantified values in magmatic crystallized zircons. The Cenozoic age (mean of 30.78 ± 0.28 Ma) obtained for zircon inclusions is close to the age of some igneous rocks found within the Cameroon Volcanic Line (e.g. rocks of the Mount Oku: 31-22 Ma), showing the same period of formation. The most probable source of the zircon host sapphires is the Oku Mountain located SW of Mayo Kila.

  13. Central nervous system recurrence of systemic lymphoma in the era of stem cell transplantation - An international primary central nervous system lymphoma study group project

    NARCIS (Netherlands)

    J.E.C. Bromberg (Jacolien); J.K. Doorduijn (Jeanette); G. Illerhaus (Gerald); K. Jahnke (Kristoph); A. Korfe (Agniezka); L. Fischer (Lutz); K. Fritsch (Kristina); O. Kuittinen (Outi); S. Issa (Samar); C.A.G.M. Montfort (Kees); M.J. van den Bent (Martin)

    2013-01-01

    textabstractAutologous stem cell transplantation has greatly improved the prognosis of systemic recurrent non-Hodgkin's lymphoma. However, no prospective data are available concerning the feasibility and efficacy of this strategy for systemic lymphoma relapsing in the central nervous system. We, the

  14. Estimation of the geothermal potential of the Caldara di Manziana site in the Mts Sabatini Volcanic District (Central Italy) by integrating geochemical data and 3D-GIS modelling.

    Science.gov (United States)

    Ranaldi, Massimo; Lelli, Matteo; Tarchini, Luca; Carapezza, Maria Luisa; Patera, Antonio

    2016-04-01

    High-enthalpy geothermal fields of Central Italy are hosted in deeply fractured carbonate reservoirs occurring in thermally anomalous and seismically active zones. However, the Mts. Sabatini volcanic district, located north of Rome, has an interesting deep temperatures (T), but it is characterized by low to very low seismicity and permeability in the reservoir rocks (mostly because of hydrothermal self-sealing processes). Low PCO2 facilitates the complete sealing of the reservoir fractures, preventing hot fluids rising and, determining a low CO2 flux at the surface. Conversely, high CO2 flux generally reflects a high pressure of CO2, suggesting that an active geothermal reservoir is present at depth. In Mts. Sabatini district, the Caldara of Manziana (CM) is the only zone characterized by a very high CO2 flux (188 tons/day) from a surface of 0.15 km2) considering both the diffuse and viscous CO2 emission. This suggests the likely presence of an actively degassing geothermal reservoir at depth. Emitted gas is dominated by CO2 (>97 vol.%). Triangular irregular networks (TINs) have been used to represent the morphology of the bottom of the surficial volcanic deposits, the thickness of the impervious formation and the top of the geothermal reservoir. The TINs, integrated by T-gradient and deep well data, allowed to estimate the depth and the temperature of the top of the geothermal reservoir, respectively to ~-1000 m from the surface and to ~130°C. These estimations are fairly in agreement with those obtained by gas chemistry (818lake is the most thermally anomalous zone of the area. Geothermometers and the GIS model indicated a temperature range between 120 and 150°C, confirming the presence of a medium-enthalpy geothermal resource in the Mts. Sabatini, but only at CM the low depth of the geothermal reservoir (~-1000m) makes this resource economically attractive.

  15. Engineering Biomaterial Properties for Central Nervous System Applications

    Science.gov (United States)

    Rivet, Christopher John

    Biomaterials offer unique properties that are intrinsic to the chemistry of the material itself or occur as a result of the fabrication process; iron oxide nanoparticles are superparamagnetic, which enables controlled heating in the presence of an alternating magnetic field, and a hydrogel and electrospun fiber hybrid material provides minimally invasive placement of a fibrous, artificial extracellular matrix for tissue regeneration. Utilization of these unique properties towards central nervous system disease and dysfunction requires a thorough definition of the properties in concert with full biological assessment. This enables development of material-specific features to elicit unique cellular responses. Iron oxide nanoparticles are first investigated for material-dependent, cortical neuron cytotoxicity in vitro and subsequently evaluated for alternating magnetic field stimulation induced hyperthermia, emulating the clinical application for enhanced chemotherapy efficacy in glioblastoma treatment. A hydrogel and electrospun fiber hybrid material is first applied to a rat brain to evaluate biomaterial interface astrocyte accumulation as a function of hybrid material composition. The hybrid material is then utilized towards increasing functional engraftment of dopaminergic progenitor neural stem cells in a mouse model of Parkinson's disease. Taken together, these two scenarios display the role of material property characterization in development of biomaterial strategies for central nervous system repair and regeneration.

  16. Clinical application of MRI to fetal central nervous system

    International Nuclear Information System (INIS)

    Objective: To explore the value of MRI on fetal central nervous system. Methods: Twenty-four women with complicated pregnancies, aged from 22 to 32 years (average 27 years) and with gestation from 23-39 weeks (average 30 weeks) were studied with a 1.5T superconductive MR unit within 24 hours after ultrasound studies. T2-weighted MR imaging was performed using HASTE and T1-weighted MR imaging was using FLASH. Comparison of the diagnosis of MRI and ultrasound were done with autopsy or postnatal follow-up MRI. Results: Of the 24 cases, 24 fetus were found. The fetal brain, gyrus, sulcus, corpus callosum, thalamus, cerebellum, brain stem, and spinal cord were shown more clearly on MR T2-weighted images. T1-weighted images were not as good as T2-weighted images. Twenty-seven lesions were visualized by ultrasound and thirty-one by MRI in these twenty-four fetuses. By MRI study, two cases were conformed their ultrasound diagnosis, ten cases were completed their ultrasound diagnosis, and twelve cases were made the same diagnosis as ultrasound. Conclusion: MR has advantages in displaying fetal central nervous system anatomy over ultrasound, the quality of MR images is not affected by maternal somatotype, volume of amniotic fluid, fetal skull and the pelvic skeleton of pregnant women. Based on ultrasound, MR imaging is a valuable complement to sonography in difficult cases, it can conforming, completing, even more correcting the diagnosis made by ultrasound. (authors)

  17. Prolactin gene expression in primary central nervous system tumors

    Directory of Open Access Journals (Sweden)

    Mendes Graziella Alebrant

    2013-01-01

    Full Text Available Abstract Background Prolactin (PRL is a hormone synthesized in both the pituitary gland and extrapituitary sites. It has been associated with the occurrence of neoplasms and, more recently, with central nervous system (CNS neoplasms. The aim of this study was to evaluate prolactin expression in primary central nervous system tumors through quantitative real-time PCR and immunohistochemistry (IH. Results Patient mean age was 49.1 years (SD 15.43, and females accounted for 70% of the sample. The most frequent subtype of histological tumor was meningioma (61.5%, followed by glioblastoma (22.9%. Twenty cases (28.6% showed prolactin expression by immunohistochemistry, most of them females (18 cases, 90%. Quantitative real-time PCR did not show any prolactin expression. Conclusions Despite the presence of prolactin expression by IH, the lack of its expression by quantitative real-time PCR indicates that its presence in primary tumors in CNS is not a reflex of local production.

  18. A Rare Case of Central Nervous System Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ravish Parekh

    2014-01-01

    Full Text Available Intracranial abscess is an extremely rare form of central nervous system (CNS tuberculosis (TB. We describe a case of central nervous system tuberculous abscess in absence of human immunodeficiency virus (HIV infection. A 82-year-old Middle Eastern male from Yemen was initially brought to the emergency room due to altered mental status and acute renal failure. Cross-sectional imaging revealed multiple ring enhancing lesions located in the left cerebellum and in bilateral frontal lobe as well as in the inferior parietal lobe on the left. The patient was placed on an empiric antibiotic regimen. Preliminary testing for infectious causes was negative. Chest radiography and CT of chest showed no positive findings. He was not on any immunosuppressive medications and human immunodeficiency virus (HIV enzyme immunoassay (EIA test was negative. A subsequent MRI one month later showed profound worsening of the lesions with increasing vasogenic edema and newly found mass effect impinging on the fourth ventricle. Brain biopsy showed focal exudative cerebellitis and inflamed granulation tissue consistent with formation of abscesses. The diagnosis of CNS TB was finally confirmed by positive acid-fast bacilli (AFB cultures. The patient was started on standard tuberculosis therapy but expired due to renal failure and cardiac arrest.

  19. Genetic perspectives on the ascidian central nervous system

    Directory of Open Access Journals (Sweden)

    A Locascio

    2009-03-01

    Full Text Available In 2002, date of publication of the Ciona intestinalis genome, ascidians entered the post-genomic era. This tool had a fundamental role and has become the starting point for a series of new functional and genomic studies. Recently, great efforts have been done to characterize the genetic cascades of genes having a key role in early embryonic development and to draw the regulatory networks in which they are involved. In this review, we focused our attention on the last advances obtained in the attempt to clarify the complex molecular events governing ascidian central nervous system development with a special interest for anterior neural and sensory structures. We discussed the more recent theories on its early induction and late regionalization. In particular, we used some conserved genes fully or partially characterized as examples to compare ascidian and vertebrate central nervous system (CNS.By integrating the various results obtained with microarray, morpholino loss of function and promoter analyses, we showed that many progresses have been done to unravel the gene networks controlling early CNS induction and formation. Unfortunately, fewer advances have been done in the identification of the regulatory cascades controlling late CNS regionalization and sensory organs differentiation. Some results are discussed to point out the importance of fully characterizing also these specific regulatory cascades.

  20. Focal lesions in the central nervous system: stereotaxic radioneurosurgery

    International Nuclear Information System (INIS)

    The application of heavy-ion beams for fundamental and applied brain research has unusual potential. Methods are being developed in our laboratory for producing focal lesions in the central nervous system (e.g., the hypothalamus, thalamus, pituitary gland) to investigate nerve pathways and neuroendocrine responses, and for treating certain pathological disorders of the brain with stereotaxic Bragg peak heavy-ion radiosurgery. Studies in animals are demonstrating the value of this neuroscience tool for investigating mammalian brain response to induction of discrete focal lesions in the hypothalamus or in the cerebral cortex. These studies are also elucidating the neuroendocrinological response follwing ablation of various portions of the midbrain, without requiring complex neurosurgical preparations. Clinical studies are demonstrating the feasibility of stereotaxic neurological radiosurgery for treating certain inoperable vascular disorders of the brain [e.g., arteriovenous malformations (AVM), internal carotid artery-cavernous sinus fistulas and other cerebrovascular disorders] in patients who are already demonstrating progressive neurological deficit. Further applications of focal lesion production with the Bragg ionization peak can be extended to include localized radiation to centers of the brain and spinal cord for treatment of such disorders as Parkinson's disease, pituitary microadenomas, acoustic neuromas, and the control of pain. The eventual application of radioactive beams will provide accurate localization of the stopping points of the beam, thereby making it feasible to stop the beam accurately at a defined depth within the central nervous system

  1. Radiobiology of Radiosurgery for the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Antonio Santacroce

    2013-01-01

    Full Text Available According to Leksell radiosurgery is defined as “the delivery of a single, high dose of irradiation to a small and critically located intracranial volume through the intact skull.” Before its birth in the early 60s and its introduction in clinical therapeutic protocols in late the 80s dose application in radiation therapy of the brain for benign and malignant lesions was based on the administration of cumulative dose into a variable number of fractions. The rationale of dose fractionation is to lessen the risk of injury of normal tissue surrounding the target volume. Radiobiological studies of cell culture lines of malignant tumors and clinical experience with patients treated with conventional fractionated radiotherapy helped establishing this radiobiological principle. Radiosurgery provides a single high dose of radiation which translates into a specific toxic radiobiological response. Radiobiological investigations to study the effect of high dose focused radiation on the central nervous system began in late the 50s. It is well known currently that radiobiological principles applied for dose fractionation are not reproducible when single high dose of ionizing radiation is delivered. A review of the literature about radiobiology of radiosurgery for the central nervous system is presented.

  2. Accelerator system for the Central Japan Synchrotron Radiation Facility

    International Nuclear Information System (INIS)

    Accelerator system for Central Japan Synchrotron Radiation Research Facility that consists of 50MeV electron S-band linac, 1.2GeV full energy booster synchrotron and 1.2GeV storage ring, has been constructed. Eight 1.4T bending magnets and four 5T superconducting magnet with compact refrigerator system provide beam lines. For top-up operation, the 1ns single bunch electron beam from 50MeV injector linac is injected by on-axis injection scheme and accelerated up to 1.2GeV at booster synchrotron. The timing system is designed for injection from booster ring is possible for any bunch position of storage ring. To improve efficiency of booster injection, the electron gun trigger and RF frequency of 2856MHz is synchronized with storage ring frequency of 499.654MHz. The EPICS control system is used with timing control system for linac, pulse magnet and also for booster pattern memory system. The beam commissioning for 1.2GeV storage ring has been progressing. (author)

  3. The CMS central hadron calorimeter DAQ system upgrade

    Science.gov (United States)

    Whitbeck, A.; Hirschauer, J.

    2015-05-01

    The CMS central hadron calorimeters will undergo a complete replacement of their data acquisition system electronics. The replacement is phased, with portions of the replacement starting in 2014 and continuing through LHC Long Shutdown 2 in 2018. The existing VME electronics will be replaced with a μTCA-based system. New on-detector QIE electronics cards will transmit data at 4.8 GHz to the new μHTR cards residing in μTCA crates in the CMS electronics cavern. The μTCA crates are controlled by the AMC13, which accepts system clock and trigger throttling control from the CMS global DAQ system. The AMC13 distributes the clock to the μHTR and reads out data buffers from the μHTR into the CMS data acquisition system. The AMC 13 also provides the clock for in-crate GLIBs which in turn distribute the clock to the on-detector front end electronics. We report on the design, development status, and schedule of the DAQ system upgrades.

  4. A centralized information management system for environmental science and technology

    Energy Technology Data Exchange (ETDEWEB)

    Namboodiri, K. [Martin Marietta Technical Services, Inc., Bay City, MI (United States)

    1995-12-31

    During the past few decades there have been several serious initiatives focusing on the applications of computational technology towards understanding the diverse fields of environmental research such as environmental monitoring, pollution prevention, and hazardous chemical mitigation. Recently, due to the widespread application of high performance computer technology and the renewed interest of the industrial community in environmental protection, we are witnessing an era of environmental information explosion. In light of these large-scale computer-driven developments, the author identifies a highly desirable initiative for this field, which is solely devoted to a centralized environmental database and information management system. This talk will focus on some design aspects of such an information management system.

  5. Radiation therapy for primary central nervous system lymphoma

    Directory of Open Access Journals (Sweden)

    Yuta Shibamoto

    2013-09-01

    Full Text Available Up until the late 1970s, radiation therapy played an important role in the treatment of primary central nervous system lymphoma (PCNSL but more recently its role has changed due to the increased use of systemic chemotherapy. In this article, the current status of radiotherapy for PCNSL and optimal forms of radiotherapy, including the treatment volume and radiation dose, are discussed. Data from nationwide Japanese surveys of PCNSL patients treated with radiation therapy suggest that the prognosis of PCNSL patients improved during the 1990s, in part due to the use of high-dose methotrexate-containing chemotherapy. The prognosis of patients treated with radiation alone also improved. Radiotherapy still seems to play an important role in the attempt to cure this disease.

  6. MyOcean Central Information System - Achievements and Perspectives

    Science.gov (United States)

    Claverie, Vincent; Loubrieu, Thomas; Jolibois, Tony; de Dianous, Rémi; Blower, Jon; Romero, Laia; Griffiths, Guy

    2013-04-01

    Since 2009, MyOcean (http://www.myocean.eu) is providing an operational service, for forecasts, analysis and expertise on ocean currents, temperature, salinity, sea level, primary ecosystems and ice coverage. The production of observation and forecasting data is done by 42 Production Units (PU). Product download and visualisation are hosted by 25 Dissemination Units (DU). All these products and associated services are gathered in a single catalogue hiding the intricate distributed organization of PUs and DUs. Besides applying INSPIRE directive and OGC recommendations, MyOcean overcomes technical choices and challenges. This presentation focuses on 3 specific issues met by MyOcean and relevant for many Spatial Data Infrastructures: user's transaction accounting, large volume download and stream line the catalogue maintenance. Transaction Accounting: Set up powerful means to get detailed knowledge of system usage in order to subsequently improve the products (ocean observations, analysis and forecast dataset) and services (view, download) offer. This subject drives the following ones: Central authentication management for the distributed web services implementations: add-on to THREDDS Data Server for WMS and NETCDF sub-setting service, specific FTP. Share user management with co-funding projects. In addition to MyOcean, alternate projects also need consolidated information about the use of the cofunded products. Provide a central facility for the user management. This central facility provides users' rights to geographically distributed services and gathers transaction accounting history from these distributed services. Propose a user-friendly web interface to download large volume of data (several GigaBytes) as robust as basic FTP but intuitive and file/directory independent. This should rely on a web service drafting the INSPIRE to-be specification and OGC recommendations for download taking into account that FTP server is not enough friendly (need to know

  7. Groundwater flow system and Nitrogen cycle in volcanic aquifer of pyroclastic flow uplands, Japan

    Science.gov (United States)

    Mikami, K.; Shimada, J.; Tashiro, S.; Niimi, H.

    2007-12-01

    Study area is well-known agriculture area in Southern Kyushu, Japan and highly depends on groundwater resources for their everyday use. Local unconfined groundwater aquifer is widely polluted by Nitrate-Nitrogen originated from agriculture and cattle farming. It will become serious problem if this unconfined Nitrate pollution enlarges into the confined aquifer system which is used for local city water source. The detailed three dimensional groundwater flow system study has been done by using existing wells in the basin to understand the three dimensional distribution pattern of Nitrate-Nitrogen in the aquifer. However, the detailed groundwater age analysis by using Tritium for unconfined and confined groundwater has not been succeeded because of present low atmosphere tritium concentration. Thus we applied to challenge the CFCs dating method. Although the CFCs method has been widely used for dating the young groundwater instead of tritium in many countries, in Japan CFCs has been used only by Oceanographic study and has not been used in the field of Hydrology. The history and fate of Nitrate contamination have been shown in multidisciplinary local transect studies in areas with agricultural sources (Bohlke and Denver 1995). However, identification of Nitrogen sources can be difficult in larger regional studies because of co-occurrence of multiple anthropogenic Nitrogen sources and uncertainty in Nitrogen transformation pathways. Thus, the characterization of N geochemistry remains challenging, particularly in aquifer-scale assessments (Stephen 2006). In this study, the evidence of the shallow groundwater flowing towards deep aquifer was verified by the groundwater dating and the detailed Nitrogen reduction process was confirmed along the groundwater flow.

  8. Permeability Reduction in Passively Degassing Seawater-dominated Volcanic-hydrothermal systems: Processes and Perils on Raoul Island, Kermadecs (NZ)

    Science.gov (United States)

    Christenson, B. W.; Reyes, A. G.

    2014-12-01

    The 2006 eruption from Raoul Island occurred apparently in response to local tectonic swarm activity, but without any precursory indication of volcanic unrest within the hydrothermal system on the island. The eruption released some 200 T of SO2, implicating the involvement of a deep magmatic vapor input into the system during/prior to the event. In the absence of any recognized juvenile material in the eruption products, previous explanations for this eruptive event focused on this vapor being a driving force for the eruption. In 2004, at least 80 T/d of CO2 was escaping from the hydrothermal system, but mainly through areas that did not correspond to the 2006 eruption vents. The lack of a pre-eruptive hydrothermal system response related to the seismic event in 2006 can be explained by the presence of a hydrothermal mineralogic seal in the vent area of the volcano. Evidence for the existence of such a seal was found in eruption deposits in the form of massive fracture fillings of aragonite, calcite and anhydrite. Fluid inclusion homogenization temperatures in these phases range from ca. 140 °C to 220 °C which, for pure water indicate boiling point depths of between 40 and 230 m assuming a cold hydrostatic pressure constraint. Elevated pressures behind this seal are consistent with the occurrence of CO2 clathrates in some inclusion fluids, indicating CO2 concentrations approaching 1 molal in the parent fluids. Reactive transport modeling of magmatic volatile inputs into what is effectively a seawater-dominated hydrothermal system provide valuable insights into seal formation. Carbonate mineral phases ultimately come to saturation along this flow path, but we suggest that focused deposition of the observed massive carbonate seal is facilitated by near-surface boiling of these CO2-enriched altered seawaters, leading to large degrees of supersaturation which are required for the formation of aragonite. As the seal grew and permeability declined, pore pressures

  9. Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity

    Directory of Open Access Journals (Sweden)

    María Sofía Urbieta

    2015-07-01

    Full Text Available The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.

  10. Volcanic Eruptions and Climate

    Science.gov (United States)

    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. Scientific and public responses to the ongoing volcanic crisis at Popocatépetl Volcano, Mexico: Importance of an effective hazards-warning system

    Science.gov (United States)

    De la Cruz-Reyna, Servando; Tilling, Robert I.

    2008-02-01

    Volcanic eruptions and other potentially hazardous natural phenomena occur independently of any human actions. However, such phenomena can cause disasters when a society fails to foresee the hazardous manifestations and adopt adequate measures to reduce its vulnerability. One of the causes of such a failure is the lack of a consistent perception of the changing hazards posed by an ongoing eruption, i.e., with members of the scientific community, the Civil Protection authorities and the general public having diverging notions about what is occurring and what may happen. The problem of attaining a perception of risk as uniform as possible in a population measured in millions during an evolving eruption requires searching for communication tools that can describe—as simply as possible—the relations between the level of threat posed by the volcano, and the level of response of the authorities and the public. The hazards-warning system adopted at Popocatépetl Volcano, called the Volcanic Traffic Light Alert System (VTLAS), is a basic communications protocol that translates volcano threat into seven levels of preparedness for the emergency-management authorities, but only three levels of alert for the public (color coded green-yellow-red). The changing status of the volcano threat is represented as the most likely scenarios according to the opinions of an official scientific committee analyzing all available data. The implementation of the VTLAS was intended to reduce the possibility of ambiguous interpretations of intermediate levels by the endangered population. Although the VTLAS is imperfect and has not solved all problems involved in mass communication and decision-making during a volcanic crisis, it marks a significant advance in the management of volcanic crises in Mexico.

  12. Scientific and public responses to the ongoing volcanic crisis at Popocatépetl Volcano, Mexico: Importance of an effective hazards-warning system

    Science.gov (United States)

    de la Cruz-Reyna, Servando; Tilling, Robert I.

    2008-01-01

    Volcanic eruptions and other potentially hazardous natural phenomena occur independently of any human actions. However, such phenomena can cause disasters when a society fails to foresee the hazardous manifestations and adopt adequate measures to reduce its vulnerability. One of the causes of such a failure is the lack of a consistent perception of the changing hazards posed by an ongoing eruption, i.e., with members of the scientific community, the Civil Protection authorities and the general public having diverging notions about what is occurring and what may happen. The problem of attaining a perception of risk as uniform as possible in a population measured in millions during an evolving eruption requires searching for communication tools that can describe—as simply as possible—the relations between the level of threat posed by the volcano, and the level of response of the authorities and the public. The hazards-warning system adopted at Popocatépetl Volcano, called the Volcanic Traffic Light Alert System(VTLAS), is a basic communications protocol that translates volcano threat into seven levels of preparedness for the emergency-management authorities, but only three levels of alert for the public (color coded green–yellow–red). The changing status of the volcano threat is represented as the most likely scenarios according to the opinions of an official scientific committee analyzing all available data. The implementation of the VTLAS was intended to reduce the possibility of ambiguous interpretations of intermediate levels by the endangered population. Although the VTLAS is imperfect and has not solved all problems involved in mass communication and decision-making during a volcanic crisis, it marks a significant advance in the management of volcanic crises in Mexico.

  13. Volcanic Eruptions and Climate

    Science.gov (United States)

    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. The role of microbiome in central nervous system disorders.

    Science.gov (United States)

    Wang, Yan; Kasper, Lloyd H

    2014-05-01

    Mammals live in a co-evolutionary association with the plethora of microorganisms that reside at a variety of tissue microenvironments. The microbiome represents the collective genomes of these co-existing microorganisms, which is shaped by host factors such as genetics and nutrients but in turn is able to influence host biology in health and disease. Niche-specific microbiome, prominently the gut microbiome, has the capacity to effect both local and distal sites within the host. The gut microbiome has played a crucial role in the bidirectional gut-brain axis that integrates the gut and central nervous system (CNS) activities, and thus the concept of microbiome-gut-brain axis is emerging. Studies are revealing how diverse forms of neuro-immune and neuro-psychiatric disorders are correlated with or modulated by variations of microbiome, microbiota-derived products and exogenous antibiotics and probiotics. The microbiome poises the peripheral immune homeostasis and predisposes host susceptibility to CNS autoimmune diseases such as multiple sclerosis. Neural, endocrine and metabolic mechanisms are also critical mediators of the microbiome-CNS signaling, which are more involved in neuro-psychiatric disorders such as autism, depression, anxiety, stress. Research on the role of microbiome in CNS disorders deepens our academic knowledge about host-microbiome commensalism in central regulation and in practicality, holds conceivable promise for developing novel prognostic and therapeutic avenues for CNS disorders.

  15. Low-level microwave irradiation and central cholinergic systems

    Energy Technology Data Exchange (ETDEWEB)

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W. (Univ. of Washington School of Medicine, Seattle (USA))

    1989-05-01

    Our previous research showed that 45 min of exposure to low-level, pulsed microwaves (2450-MHz, 2-microseconds pulses, 500 pps, whole-body average specific absorption rate 0.6 W/kg) decreased sodium-dependent high-affinity choline uptake in the frontal cortex and hippocampus of the rat. The effects of microwaves on central cholinergic systems were further investigated in this study. Increases in choline uptake activity in the frontal cortex, hippocampus, and hypothalamus were observed after 20 min of acute microwave exposure, and tolerance to the effect of microwaves developed in the hypothalamus, but not in the frontal cortex and hippocampus, of rats subjected to ten daily 20-min exposure sessions. Furthermore, the effects of acute microwave irradiation on central choline uptake could be blocked by pretreating the animals before exposure with the narcotic antagonist naltrexone. In another series of experiments, rats were exposed to microwaves in ten daily sessions of either 20 or 45 min, and muscarinic cholinergic receptors in different regions of the brain were studied by 3H-QNB binding assay. Decreases in concentration of receptors occurred in the frontal cortex and hippocampus of rats subjected to ten 20-min microwave exposure sessions, whereas increase in receptor concentration occurred in the hippocampus of animals exposed to ten 45-min sessions. This study also investigated the effects of microwave exposure on learning in the radial-arm maze. Rats were trained in the maze to obtain food reinforcements immediately after 20 or 45 min of microwave exposure.

  16. Impact of an extremely large magnitude volcanic eruption on the global climate and carbon cycle estimated from ensemble Earth System Model simulations

    Directory of Open Access Journals (Sweden)

    J. Segschneider

    2012-07-01

    Full Text Available The response of the global climate-carbon cycle system to an extremely large Northern Hemisphere mid latitude volcanic eruption is investigated using ensemble integrations with the comprehensive Earth System Model MPI-ESM. The model includes dynamical compartments of the atmosphere and ocean and interactive modules of the terrestrial biosphere as well as ocean biogeochemistry. The MPI-ESM was forced with anomalies of aerosol optical depth and effective radius of aerosol particles corresponding to a super eruption of the Yellowstone volcanic system. The model experiment consists of an ensemble of fifteen model integrations that are started at different pre-ENSO states of a contol experiment and run for 200 yr after the volcanic eruption. The climate response to the volcanic eruption is a maximum global monthly mean surface air temperature cooling of 3.8 K for the ensemble mean and from 3.3 K to 4.3 K for individual ensemble members. Atmospheric pCO2 decreases by a maximum of 5 ppm for the ensemble mean and by 3 ppm to 7 ppm for individual ensemble members approximately 6 yr after the eruption. The atmospheric carbon content only very slowly returns to near pre-eruption level at year 200 after the eruption. The ocean takes up carbon shortly after the eruption in response to the cooling, changed wind fields, and ice cover. This physics driven uptake is weakly counteracted by a reduction of the biological export production mainly in the tropical Pacific. The land vegetation pool shows a distinct loss of carbon in the initial years after the eruption which has not been present in simulations of smaller scale eruptions. The gain of the soil carbon pool determines the amplitude of the CO2 perturbation and the long term behaviour of the overall system: an initial gain caused by reduced soil respiration is followed by a rather slow return towards pre-eruption levels. During this phase, the ocean compensates partly for the

  17. Impact of an extremely large magnitude volcanic eruption on the global climate and carbon cycle estimated from ensemble Earth System Model simulations

    Directory of Open Access Journals (Sweden)

    J. Segschneider

    2013-02-01

    Full Text Available The response of the global climate-carbon cycle system to an extremely large Northern Hemisphere mid-latitude volcanic eruption is investigated using ensemble integrations with the comprehensive Earth System Model MPI-ESM. The model includes dynamical compartments of the atmosphere and ocean and interactive modules of the terrestrial biosphere as well as ocean biogeochemistry. The MPI-ESM was forced with anomalies of aerosol optical depth and effective radius of aerosol particles corresponding to a super eruption of the Yellowstone volcanic system. The model experiment consists of an ensemble of fifteen model integrations that are started at different pre-ENSO states of a control experiment and run for 200 years after the volcanic eruption. The climate response to the volcanic eruption is a maximum global monthly mean surface air temperature cooling of 3.8 K for the ensemble mean and from 3.3 K to 4.3 K for individual ensemble members. Atmospheric pCO2 decreases by a maximum of 5 ppm for the ensemble mean and by 3 ppm to 7 ppm for individual ensemble members approximately 6 years after the eruption. The atmospheric carbon content only very slowly returns to near pre-eruption level at year 200 after the eruption. The ocean takes up carbon shortly after the eruption in response to the cooling, changed wind fields and ice cover. This physics-driven uptake is weakly counteracted by a reduction of the biological export production mainly in the tropical Pacific. The land vegetation pool shows a decrease by 4 GtC due to reduced short-wave radiation that has not been present in a smaller scale eruption. The gain of the soil carbon pool determines the amplitude of the CO2 perturbation and the long-term behaviour of the overall system: an initial gain caused by reduced soil respiration is followed by a rather slow return towards pre-eruption levels. During this phase, the ocean compensates partly for the reduced atmospheric

  18. Fungal Infections of the Central Nervous System: A Pictorial Review.

    Science.gov (United States)

    Gavito-Higuera, Jose; Mullins, Carola Birgit; Ramos-Duran, Luis; Olivas Chacon, Cristina Ivette; Hakim, Nawar; Palacios, Enrique

    2016-01-01

    Fungal infections of the central nervous system (CNS) pose a threat to especially immunocompromised patients and their development is primarily determined by the immune status of the host. With an increasing number of organ transplants, chemotherapy, and human immunodeficiency virus infections, the number of immunocompromised patients as susceptible hosts is growing and fungal infections of the CNS are more frequently encountered. They may result in meningitis, cerebritis, abscess formation, cryptococcoma, and meningeal vasculitis with rapid disease progression and often overlapping symptoms. Although radiological characteristics are often nonspecific, unique imaging patterns can be identified through computer tomography as a first imaging modality and further refined by magnetic resonance imaging. A rapid diagnosis and the institution of the appropriate therapy are crucial in helping prevent an often fatal outcome. PMID:27403402

  19. Studies on central nervous system serotonin receptors in mood disorders.

    Science.gov (United States)

    Young, A; Goodwin, G M

    1991-01-01

    The evidence from studies of central nervous system serotonin (5-HT) receptors is reviewed and the role of these in the pathogenesis of mood disorders is discussed. Clinical evidence indicates that 5-HT function is abnormal in mood disorders. 5-HT precursors and selective inhibitors of 5-HT uptake are effective antidepressives and inhibition of 5-HT synthesis can block the action of antidepressives. Studies of 5-HT in experimental animals after chronic administration of antidepressive treatments suggest that intact 5-HT neurons are necessary for the action of these treatments. Multiple 5-HT receptor subtypes have recently been identified and the effects of chronic antidepressive treatment on some receptor subtypes function in experimental animals have been established. The increasing availability of powerful new in vivo imaging techniques like single photon emission tomography (SPET), and positron emission tomography (PET) may make possible a more direct examination of 5-HT receptor function in patients suffering from mood disorders. PMID:2029163

  20. Primary central nervous system lymphoma a report of nine cases.

    Science.gov (United States)

    Lakshmaiah, K C; Lokanath, D; Ramesh, C; Babu, K G; Rao, C R; Swamy, K

    1996-06-01

    Primary Central Nervous System Lymphoma (PCNSL) is a rare neoplasm of B cell origin and constitute less than 1% of Non-Hodgkin's lymphoma (NHL). Histology is mainly of high grade and intermediate type. Although NHL is known to be highly sensitive to both irradiation and cytotoxic drugs, being a curable malignancy, the therapeutic results remain disappointing. Clinical observations on nine cases of PCNSL seen in one of the major cancer centres in India is presented in this paper. Radiotherapy combined with Chemotherapy although yielded encouraging initial response in these patients, the long term response was unsatisfactory with median survival for these patients being only 19 months. This warrants an alternative therapeutic approach to improve the dismal prognosis of PCNSL. PMID:8979473

  1. Neuroinvasion and Inflammation in Viral Central Nervous System Infections

    Science.gov (United States)

    Schroten, Horst

    2016-01-01

    Neurotropic viruses can cause devastating central nervous system (CNS) infections, especially in young children and the elderly. The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) have been described as relevant sites of entry for specific viruses as well as for leukocytes, which are recruited during the proinflammatory response in the course of CNS infection. In this review, we illustrate examples of established brain barrier models, in which the specific reaction patterns of different viral families can be analyzed. Furthermore, we highlight the pathogen specific array of cytokines and chemokines involved in immunological responses in viral CNS infections. We discuss in detail the link between specific cytokines and chemokines and leukocyte migration profiles. The thorough understanding of the complex and interrelated inflammatory mechanisms as well as identifying universal mediators promoting CNS inflammation is essential for the development of new diagnostic and treatment strategies. PMID:27313404

  2. Theory of cellwise optimization for solar central receiver system

    Science.gov (United States)

    Lipps, F. W.

    1985-05-01

    Cost effective optimization of the solar central receiver system is primarily concerned with the distribution of heliostats in the collector field, including the boundaries of the field. The cellwise optimization procedure determines the optimum cell usage and heliostat spacing parameters for each cell in the collector field. Spacing parameters determine the heliostat density and neighborhood structure uniformly in each cell. Consequently, the cellwise approach ignores heliostat mismatch at cell boundaries. Ignoring the cell boundary problem permits an easy solution for the optimum in terms of appropriately defined annual average data. Insolation, receiver interception, shading and blocking, cosine effects, and the cost parameters combine to control the optimum. Many trade offs are represented. Outputs include the receiver flux density distribution for design time, coefficients for an actual layout, the optimum boundary and various performance and cost estimates for the optimum field. It is also possible to optimize receiver size and tower height by a repeated application of the field optimization procedure.

  3. Are astrocytes executive cells within the central nervous system?

    Science.gov (United States)

    Sica, Roberto E; Caccuri, Roberto; Quarracino, Cecilia; Capani, Francisco

    2016-08-01

    Experimental evidence suggests that astrocytes play a crucial role in the physiology of the central nervous system (CNS) by modulating synaptic activity and plasticity. Based on what is currently known we postulate that astrocytes are fundamental, along with neurons, for the information processing that takes place within the CNS. On the other hand, experimental findings and human observations signal that some of the primary degenerative diseases of the CNS, like frontotemporal dementia, Parkinson's disease, Alzheimer's dementia, Huntington's dementia, primary cerebellar ataxias and amyotrophic lateral sclerosis, all of which affect the human species exclusively, may be due to astroglial dysfunction. This hypothesis is supported by observations that demonstrated that the killing of neurons by non-neural cells plays a major role in the pathogenesis of those diseases, at both their onset and their progression. Furthermore, recent findings suggest that astrocytes might be involved in the pathogenesis of some psychiatric disorders as well. PMID:27556379

  4. Central nervous system stimulants and drugs that suppress appetite

    DEFF Research Database (Denmark)

    Aagaard, Lise

    2014-01-01

    The Side Effects of Drugs Annuals form a series of volumes in which the adverse effects of drugs and adverse reactions to them are surveyed. The series supplements the contents of Meyler's Side Effects of Drugs: the International Encyclopedia of Adverse Drug Reactions and Interactions. This revie......, methylxanthines (caffeine and theophylline), drugs that suppress appetite (phentermine, rimonabant, and sibutramine) and drugs used in Alzheimer's disease (donepezil and rivastigmine).......The Side Effects of Drugs Annuals form a series of volumes in which the adverse effects of drugs and adverse reactions to them are surveyed. The series supplements the contents of Meyler's Side Effects of Drugs: the International Encyclopedia of Adverse Drug Reactions and Interactions. This review...... of the January 2012 to June 2013 publications on central nervous system stimulants and drugs that suppress appetite covers amphetamines (including metamfetamine, paramethoxyamfetamine and paramethoxymetamfetamine), fenfluramine and benfluorex, atomoxetine, methylphenidate, modafinil and armodafinil...

  5. Electrical stimuli in the central nervous system microenvironment.

    Science.gov (United States)

    Thompson, Deanna M; Koppes, Abigail N; Hardy, John G; Schmidt, Christine E

    2014-07-11

    Electrical stimulation to manipulate the central nervous system (CNS) has been applied as early as the 1750s to produce visual sensations of light. Deep brain stimulation (DBS), cochlear implants, visual prosthetics, and functional electrical stimulation (FES) are being applied in the clinic to treat a wide array of neurological diseases, disorders, and injuries. This review describes the history of electrical stimulation of the CNS microenvironment; recent advances in electrical stimulation of the CNS, including DBS to treat essential tremor, Parkinson's disease, and depression; FES for the treatment of spinal cord injuries; and alternative electrical devices to restore vision and hearing via neuroprosthetics (retinal and cochlear implants). It also discusses the role of electrical cues during development and following injury and, importantly, manipulation of these endogenous cues to support regeneration of neural tissue. PMID:25014787

  6. Cell fate control in the developing central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Guérout, Nicolas; Li, Xiaofei; Barnabé-Heider, Fanie, E-mail: Fanie.Barnabe-Heider@ki.se

    2014-02-01

    The principal neural cell types forming the mature central nervous system (CNS) are now understood to be diverse. This cellular subtype diversity originates to a large extent from the specification of the earlier proliferating progenitor populations during development. Here, we review the processes governing the differentiation of a common neuroepithelial cell progenitor pool into mature neurons, astrocytes, oligodendrocytes, ependymal cells and adult stem cells. We focus on studies performed in mice and involving two distinct CNS structures: the spinal cord and the cerebral cortex. Understanding the origin, specification and developmental regulators of neural cells will ultimately impact comprehension and treatments of neurological disorders and diseases. - Highlights: • Similar mechanisms regulate cell fate in different CNS cell types and structures. • Cell fate regulators operate in a spatial–temporal manner. • Different neural cell types rely on the generation of a diversity of progenitor cells. • Cell fate decision is dictated by the integration of intrinsic and extrinsic signals.

  7. Modulation of Tumor Tolerance in Primary Central Nervous System Malignancies

    Directory of Open Access Journals (Sweden)

    Theodore S. Johnson

    2012-01-01

    Full Text Available Central nervous system tumors take advantage of the unique immunology of the CNS and develop exquisitely complex stromal networks that promote growth despite the presence of antigen-presenting cells and tumor-infiltrating lymphocytes. It is precisely this immunological paradox that is essential to the survival of the tumor. We review the evidence for functional CNS immune privilege and the impact it has on tumor tolerance. In this paper, we place an emphasis on the role of tumor-infiltrating myeloid cells in maintaining stromal and vascular quiescence, and we underscore the importance of indoleamine 2,3-dioxygenase activity as a myeloid-driven tumor tolerance mechanism. Much remains to be discovered regarding the tolerogenic mechanisms by which CNS tumors avoid immune clearance. Thus, it is an open question whether tumor tolerance in the brain is fundamentally different from that of peripheral sites of tumorigenesis or whether it simply stands as a particularly strong example of such tolerance.

  8. MRT of the central nervous system; MRT des Zentralnervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Forsting, M.; Jansen, O. (eds.)

    2006-07-01

    The book presents the state of the art of MRT imaging of the central nervous system. Detailed information is presented in order to provide sufficient knowledge for the medical diagnostician to discuss any case encountered at eye level with the clinical physician. The book is an indispensable reference manual and a quick orientation already during examination in difficult cases. It contains images made with the most recent technology and with excellent representation of details. Even rare findings are described in detail. The imaging principle is illustrated by more than 1000 pictures and graphical representations as well as more than 100 complementary tables. Findings are classified by regions, i.e. 'brain' and 'spinal cord', including anatomical descriptions. (orig.)

  9. Magnetic resonance imaging in central nervous system tuberculosis

    International Nuclear Information System (INIS)

    Tuberculosis (TB) in any form is a devastating disease, which in its most severe form involves the central nervous system (CNS), with a high mortality and morbidity. Early diagnosis of CNS TB is necessary for appropriate treatment to reduce this morbidity and mortality. Routine diagnostic techniques involve culture and immunological tests of the tissue and biofluids, which are time-consuming and may delay definitive management. Noninvasive imaging modalities such as computed tomography (CT) scan and magnetic resonance imaging (MRI) are routinely used in the diagnosis of neurotuberculosis, with MRI offering greater inherent sensitivity and specificity than CT scan. In addition to conventional MRI imaging, magnetization transfer imaging, diffusion imaging, and proton magnetic resonance spectroscopy techniques are also being evaluated for better tissue characterization in CNS TB. The current article reviews the role of various MRI techniques in the diagnosis and management of CNS TB

  10. Primary angiitis of the central nervous system: a case report

    Institute of Scientific and Technical Information of China (English)

    YU Xiao-lin; LIU Ai-fen; MA Lin; YAN Chuan-zhu; ZHAO Yu-ying; SHAN Pei-yan

    2011-01-01

    Primary angiitis of the central nervous system is a rare and difficult entity.Here we represented the clinical and pathological features of a patient with little response to steroid before definite diagnosis.The 50-year-old male had a fluctuating disease course for more than 3 years.He presented visual disorders,seizure,cognitive impairment,hypersomnia,unsteady gait,dysphasia,dysphagia,and incontinence.Magnetic resonance imaging showed multiple,supratentorial and infratentorial abnormal signals,while cerebrospinal fluid and cerebral angiography were normal.Magnetic resonance spectrum showed a decrease of N-acetyl-aspartate.Brain biopsy revealed nongranulomatous lymphatic vasculitis with reactive gliosis,cicatrization,demyelination and focal hemorrhages.

  11. Tuberculous Panophthalmitis with Lymphadenitis and Central Nervous System Tuberculoma

    Directory of Open Access Journals (Sweden)

    Sirawat Srichatrapimuk

    2016-01-01

    Full Text Available Tuberculosis (TB is a serious infectious disease that spreads globally. The ocular manifestations of TB are uncommon and diverse. TB panophthalmitis has been rarely reported. Here, we described a 38-year-old Thai man presenting with panophthalmitis of the right eye. Further investigation showed that he had concurrent TB lymphadenitis and central nervous system (CNS tuberculoma, as well as HIV infection, with a CD4 cell count of 153 cells/mm3. Despite the initial response to antituberculous agents, the disease had subsequently progressed and enucleation was required. The pathological examination revealed acute suppurative granulomatous panophthalmitis with retinal detachment. Further staining demonstrated acid-fast bacilli in the tissue. Colonies of Mycobacterium tuberculosis were obtained from tissue culture. He was treated with antiretroviral agents for HIV infection and 12 months of antituberculous agents. Clinicians should be aware of the possibility of TB in the differential diagnosis of endophthalmitis and panophthalmitis, especially in regions where TB is endemic.

  12. Optimized optical clearing method for imaging central nervous system

    Science.gov (United States)

    Yu, Tingting; Qi, Yisong; Gong, Hui; Luo, Qingming; Zhu, Dan

    2015-03-01

    The development of various optical clearing methods provides a great potential for imaging entire central nervous system by combining with multiple-labelling and microscopic imaging techniques. These methods had made certain clearing contributions with respective weaknesses, including tissue deformation, fluorescence quenching, execution complexity and antibody penetration limitation that makes immunostaining of tissue blocks difficult. The passive clarity technique (PACT) bypasses those problems and clears the samples with simple implementation, excellent transparency with fine fluorescence retention, but the passive tissue clearing method needs too long time. In this study, we not only accelerate the clearing speed of brain blocks but also preserve GFP fluorescence well by screening an optimal clearing temperature. The selection of proper temperature will make PACT more applicable, which evidently broaden the application range of this method.

  13. Central nervous system syndromes in solid organ transplant recipients.

    Science.gov (United States)

    Wright, Alissa J; Fishman, Jay A

    2014-10-01

    Solid organ transplant recipients have a high incidence of central nervous system (CNS) complications, including both focal and diffuse neurologic deficits. In the immunocompromised host, the initial clinical evaluation must focus on both life-threatening CNS infections and vascular or anatomic lesions. The clinical signs and symptoms of CNS processes are modified by the immunosuppression required to prevent graft rejection. In this population, these etiologies often coexist with drug toxicities and metabolic abnormalities that complicate the development of a specific approach to clinical management. This review assesses the multiple risk factors for CNS processes in solid organ transplant recipients and establishes a timeline to assist in the evaluation and management of these complex patients.

  14. Fungal central nervous system infections: prevalence and diagnosis.

    Science.gov (United States)

    Kourbeti, Irene S; Mylonakis, Eleftherios

    2014-02-01

    Fungal infections of the central nervous system (CNS) are rare but they pose a significant challenge. Their prevalence spans a wide array of hosts including immunosuppressed and immunocompetent individuals, patients undergoing neurosurgical procedures and those carrying implantable CNS devices. Cryptococcus neoformans and Aspergillus spp. remain the most common pathogens. Magnetic resonance imaging can help localize the lesions, but diagnosis is challenging since invasive procedures may be needed for the retrieval of tissue, especially in cases of fungal abscesses. Antigen and antibody tests are available and approved for use in the cerebrospinal fluid (CSF). PCR-based techniques are promising but they are not validated for use in the CSF. This review provides an overview on the differential diagnosis of the fungal CNS disease based on the host and the clinical syndrome and suggests the optimal use of diagnostic techniques. It also summarizes the emergence of Cryptococcus gatti and an unanticipated outbreak caused by Exserohilum rostratum.

  15. Therapeutic approaches of magnetic nanoparticles for the central nervous system.

    Science.gov (United States)

    Dilnawaz, Fahima; Sahoo, Sanjeeb Kumar

    2015-10-01

    The diseases of the central nervous system (CNS) represent one of the fastest growing areas of concern requiring urgent medical attention. Treatment of CNS ailments is hindered owing to different physiological barriers including the blood-brain barrier (BBB), which limits the accessibility of potential drugs. With the assistance of a nanotechnology-based drug delivery strategy, the problems could be overcome. Recently, magnetic nanoparticles (MNPs) have proven immensely useful as drug carriers for site-specific delivery and as contrast agents owing to their magnetic susceptibility and biocompatibility. By utilizing MNPs, diagnosis and treatment of CNS diseases have progressed by overcoming the hurdles of the BBB. In this review, the therapeutic aspect and the future prospects related to the theranostic approach of MNPs are discussed.

  16. Adult neural stem cells in the mammalian central nervous system

    Institute of Scientific and Technical Information of China (English)

    Dengke K Ma; Michael A Bonaguidi; Guo-li Ming; Hongjun Song

    2009-01-01

    Neural stem cells (NSCs) are present not only during the embryonic development but also in the adult brain of all mammalian species, including humans. Stem cell niche architecture in vivo enables adult NSCs to continuously generate functional neurons in specific brain regions throughout life. The adult neurogenesis process is subject to dynamic regulation by various physiological, pathological and pharmacological stimuli. Multipotent adult NSCs also appear to be intrinsically plastic, amenable to genetic programing during normal differentiation, and to epigenetic reprograming during de-differentiation into pluripotency. Increasing evidence suggests that adult NSCs significantly contribute to specialized neural functions under physiological and pathological conditions. Fully understanding the biology of adult NSCs will provide crucial insights into both the etiology and potential therapeutic interventions of major brain disorders. Here, we review recent progress on adult NSCs of the mammalian central nervous system, in-cluding topics on their identity, niche, function, plasticity, and emerging roles in cancer and regenerative medicine.

  17. Radiologic findings of cysticercosis involving central nervous system

    International Nuclear Information System (INIS)

    The diagnosis of cysticercosis of central nervous system should be considered in patients with seizures, symptoms of increased I.C.P. or focal neurologic sign, with a history of having lived in an endemic area, particularly in Korea. Since these cysts usually continue to grew and medical treatment is very limited it is important to identify them and consider the feasibility of removing them surgically. 20 cases of surgically proven cysticercosis of the central nervous system were radiologically analyzed, experienced at Seoul National University Hospital. Radiologic studies include plain radiography of the skull, angiography, and CT scanning which is especially effective in diagnosis of diffuse parenchymal cysticercosis.The results are as follows: 1. Male to female ratio is 11 : 9 and mean age of the patients is 36 years. The cardinal symptoms and sign are seizures (50%), symptoms of increased I.C.P. (45%). mental change (20%) and focal neurologic sign (20%). 2. The distribution od cysts are cerebral parenchymal (40%), 4th ventricle (30%), 3rd ventricle (10%), leptomeningeal (30%), and intraspinal form (15%). 3. Simple skull film shows sign of increased I.C.P. (25%) but no case of calcification. In carotid angiography hydrocephalus is detected in all 13 cases. Displacement of adjacent vessels is seen n 2 cases of parenchymal form. Ventriculography shows dilated ventricles with free floating avoid filling defect in intraventricular form and 4th ventricle obstruction in leptomeningeal form. 4. Of spinal cysticercosis 2 cases are leptomeningeal and 1 case intramedullary form. 2 case are found in cervical portion and 1 case in cauda equina region. Myelography reveals filling defect not distinguishable from other tumorous condition.

  18. Radiologic findings of cysticercosis involving central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Hwan; Chang, Kee Hyun; Kang, Ik Won; Han, Man Chung; Choi, Kil Soo; Sim, Bo Sung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-12-15

    The diagnosis of cysticercosis of central nervous system should be considered in patients with seizures, symptoms of increased I.C.P. or focal neurologic sign, with a history of having lived in an endemic area, particularly in Korea. Since these cysts usually continue to grew and medical treatment is very limited it is important to identify them and consider the feasibility of removing them surgically. 20 cases of surgically proven cysticercosis of the central nervous system were radiologically analyzed, experienced at Seoul National University Hospital. Radiologic studies include plain radiography of the skull, angiography, and CT scanning which is especially effective in diagnosis of diffuse parenchymal cysticercosis.The results are as follows: 1. Male to female ratio is 11 : 9 and mean age of the patients is 36 years. The cardinal symptoms and sign are seizures (50%), symptoms of increased I.C.P. (45%). mental change (20%) and focal neurologic sign (20%). 2. The distribution od cysts are cerebral parenchymal (40%), 4th ventricle (30%), 3rd ventricle (10%), leptomeningeal (30%), and intraspinal form (15%). 3. Simple skull film shows sign of increased I.C.P. (25%) but no case of calcification. In carotid angiography hydrocephalus is detected in all 13 cases. Displacement of adjacent vessels is seen n 2 cases of parenchymal form. Ventriculography shows dilated ventricles with free floating avoid filling defect in intraventricular form and 4th ventricle obstruction in leptomeningeal form. 4. Of spinal cysticercosis 2 cases are leptomeningeal and 1 case intramedullary form. 2 case are found in cervical portion and 1 case in cauda equina region. Myelography reveals filling defect not distinguishable from other tumorous condition.

  19. Central nervous system recurrence of systemic lymphoma in the era of stem cell transplantation--an International Primary Central Nervous System Lymphoma Study Group project.

    Science.gov (United States)

    Bromberg, Jacoline E; Doorduijn, Jeanette K; Illerhaus, Gerald; Jahnke, Kristoph; Korfel, Agniezka; Fischer, Lars; Fritsch, Kristina; Kuittinen, Outti; Issa, Samar; van Montfort, Cees; van den Bent, Martin J

    2013-05-01

    Autologous stem cell transplantation has greatly improved the prognosis of systemic recurrent non-Hodgkin's lymphoma. However, no prospective data are available concerning the feasibility and efficacy of this strategy for systemic lymphoma relapsing in the central nervous system. We, therefore, we performed an international multicenter retrospective study of patients with a central nervous system recurrence of systemic lymphoma to assess the outcome of these patients in the era of stem cell transplantation. We collected clinical and treatment data on patients with a first central nervous system recurrence of systemic lymphoma treated between 2000 and 2010 in one of five centers in four countries. Patient- and treatment-related factors were analyzed and compared descriptively. Primary outcome measures were overall survival and percentage of patients transplanted. We identified 92 patients, with a median age of 59 years and a median Eastern Cooperative Oncology Group/World Health Organization performance status of 2, of whom 76% had diffuse large B-cell histology. The majority (79%) of these patients were treated with systemic chemotherapy with or without intravenous rituximab. Twenty-seven patients (29%) were transplanted; age and insufficient response to induction chemotherapy were the main reasons for not being transplanted in the remaining 65 patients. The median overall survival was 7 months (95% confidence interval 2.6-11.4), being 8 months (95% confidence interval 3.8-5.2) for patients ≤ 65 years old. The 1-year survival rate was 34.8%; of the 27 transplanted patients 62% survived more than 1 year. The Memorial Sloan Kettering Prognostic Index for primary central nervous system lymphoma was prognostic for both undergoing transplantation and survival. In conclusion, despite the availability of autologous stem cell transplantation for patients with central nervous system progression or relapse of systemic lymphoma, prognosis is still poor. Long-term survival

  20. Central nervous control of energy and glucose balance: focus on the central melanocortin system

    OpenAIRE

    Xu, Yong; Elmquist, Joel K.; Fukuda, Makoto

    2011-01-01

    Studies have suggested that manipulations of the central melanocortin circuitry by pharmacological agents produce robust effects on the regulation of body weight and glucose homeostasis. In this review, we discuss recent findings from genetic mouse models that have further established the physiological relevance of this circuitry in the context of glucose and energy balance. In addition, we will discuss distinct neuronal populations that respond to central melanocortins to regulate food intak...

  1. Economic sustainability of organic dairy sheep systems in Central Spain

    Directory of Open Access Journals (Sweden)

    Paula Toro-Mujica

    2015-05-01

    Full Text Available Sheep production systems in regions with a Mediterranean climate are important in social, economic and environmental terms. Modeling these systems allows, among others, evaluation of the costs efficiencies which in turn permits assessing the expected effects of changes in production variables. This paper presents a prototype analysis of the economic sustainability of ecological dairy sheep systems of Castilla-La Mancha, Central Spain evaluated through the estimation of costs efficiencies. Costs functions were developed using data from 31 farms. Rate of supplementary feeding, labour use, and flock size were used to measure the cost efficiency. On average, cost efficiency was 61.7±15.5%, with significant differences among typological groups. High efficiency was found in only 29% of the farms. The economic analyses performed suggest that the continued existence of economically unsustainably farms is explained by the available subsidies, lack of amortization of fixed assets leading to progressive decapitalization, and subsistence incomes by family groups (gross family income.

  2. GABA-ergic neurons in the leach central nervous system

    International Nuclear Information System (INIS)

    GABA is a candidate for an inhibitory neurotransmitter in the leech central nervous system because of the well-documented inhibitory action of GABA in other invertebrates. To demonstrate that GABA meets the criteria used to identify a substance as a neurotransmitter, the author examined GABA metabolism and synaptic interactions of inhibitory motor neurons in two leech species, Hirudo medicinalis and Haementeria ghilianii. Segmental ganglia of the leech ventral nerve cord and identified inhibitors have the capacity to synthesize GABA when incubated in the presence of the precursor glutamate. Application of GABA to cell bodies of excitatory motor neurons or muscle fibers innervated by the inhibitors hyperpolarizes the membrane potential of the target cell and activates a chloride ion conductance channel, similar to the inhibitory membrane response following intracellular stimulation of the inhibitor. Bicuculline methiodide (5 x 10-5M), GABA receptor antagonist, blocks reversibly the response to applied GABA and the inhibitory synaptic inputs onto the postsynaptic neurons or muscle fibers without interfering with their excitatory inputs. Furthermore, the inhibitors are included among approximately 25 neurons per segmental ganglion that take up GABA by a high affinity uptake system, as revealed by 3H-GABA-autoradiography. The development of the capacities to synthesize and to take up GABA were examined in leech embryos. The embryos are able to synthesize GABA at early stages of the development of the nervous system, before any neurons have extended neutrites

  3. The Carrán-Los Venados volcanic field and its relationship with coeval and nearby polygenetic volcanism in an intra-arc setting

    Science.gov (United States)

    Bucchi, Francisco; Lara, Luis E.; Gutiérrez, Francisco

    2015-12-01

    stable upper-crustal reservoirs. However, the CLV system seems to be at an inflection point, and could become polygenetic if magma flux increases. For PCC, high magma flux during some periods together with compressive deformation would have led to the construction of one or several stable upper-crustal magma reservoirs, with subsequent silicic volcanism and construction of central conduits for magma extrusion, resulting in polygenetic volcanism with evolved compositions. In this model, monogenetic volcanic systems can become polygenetic despite extensional regime if magma flux increases sufficiently to create and sustain a stable upper-crustal magma reservoir.

  4. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  5. System design package for the solar heating and cooling central data processing system

    Energy Technology Data Exchange (ETDEWEB)

    1978-03-01

    This system design package for the Central Data Processing System consists of the Software Performance Specification, Hardware Performance Specification, Software Verification Plan, CDPS Development Program, Qualification and Acceptance Test Procedures, Qualification Test and Analysis Report, and Qualification and Acceptance Test Review. The Central Data Processing System, located at IBM's Federal System Division facility in Huntsville, Alabama, provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications.

  6. Landslide hazards and systems analysis: A Central European perspective

    Science.gov (United States)

    Klose, Martin; Damm, Bodo; Kreuzer, Thomas

    2016-04-01

    Part of the problem with assessing landslide hazards is to understand the variable settings in which they occur. There is growing consensus that hazard assessments require integrated approaches that take account of the coupled human-environment system. Here we provide a synthesis of societal exposure and vulnerability to landslide hazards, review innovative approaches to hazard identification, and lay a focus on hazard assessment, while presenting the results of historical case studies and a landslide time series for Germany. The findings add to a growing body of literature that recognizes societal exposure and vulnerability as a complex system of hazard interactions that evolves over time as a function of social change and development. We therefore propose to expand hazard assessments by the framework and concepts of systems analysis (e.g., Liu et al., 2007) Results so far have been promising in ways that illustrate the importance of feedbacks, thresholds, surprises, and time lags in the evolution of landslide hazard and risk. In densely populated areas of Central Europe, landslides often occur in urbanized landscapes or on engineered slopes that had been transformed or created intentionally by human activity, sometimes even centuries ago. The example of Germany enables to correlate the causes and effects of recent landslides with the historical transition of urbanization to urban sprawl, ongoing demographic change, and some chronic problems of industrialized countries today, including ageing infrastructures or rising government debts. In large parts of rural Germany, the combination of ageing infrastructures, population loss, and increasing budget deficits starts to erode historical resilience gains, which brings especially small communities to a tipping point in their efforts to risk reduction. While struggling with budget deficits and demographic change, these communities are required to maintain ageing infrastructures that are particularly vulnerable to

  7. The Potential Temporal Variations in Crustal Seismic Velocity Correlated with the 2010 Jiasian Earthquake and Non-volcanic Tremors in Southern Central Range of Taiwan

    Science.gov (United States)

    Wu, S.; Hung, S.

    2013-12-01

    Different from those found in major plate boundary zones around the Pacific Rim, NVT and low-frequency earthquakes (LFEs) have been discovered in the lower crust beneath the southern segment of the CR, which comprises part of the fold-and-thrust orogenic belt in Taiwan as a product the collision between the Eurasian plate and Luzon arc. The Mw 6.0 Jiasian earthquake occurred at a focal depth of 23 km to the southwest of the identified LFEs on March 4, 2010 and ruptured upward toward the northwest, appearing accompanied by enhanced NVT activity. To investigate potential changes and causes in crustal strains and rock properties associated with the earthquake rupture and energy level of NVT after the Jiasian earthquake, we construct empirical Green's functions (EGFs) from auto- and cross-correlation functions of continuous ambient noise between available station pairs near the epicenter from the short-period Central Weather Bureau Seismic Network (CWBSN) and the Broadband Array in Taiwan for Seismology (BATS) during 2009-2011. The temporal variations in seismic velocity perturbations are estimated by measuring the relative time delay of late-arriving coda waves between short-term and long-term stacked EGFs. The resulting EGFs at 0.1-0.9 Hz show the statistically significant coseismic velocity reduction only at station pairs with the interstation paths traversing through the region exposed to the Jiasian aftershock zone, where the GPS and peak-ground acceleration (PGA) observations and finite-fault rupture model all indicate large slip and ground shaking during the main shock rupture propagation. The measured relative velocity variation is slightly temporally correlated with the daily energy calculated by squares of the velocity amplitudes in 2-7 Hz, the frequency band characteristic of main NVT energy from previously located tremor groups in southern Central Range and northeastern Taiwan. Compared with strain perturbations induced from coseismic slip distribution and

  8. Central Command Architecture for High Order Autonomous Unmanned Systems

    Science.gov (United States)

    Bieber, Chad Michael

    This dissertation describes a High-Order Central Command (HOCC) architecture and presents a flight demonstration where a single user coordinates 4 unmanned fixed-wing aircraft. HOCC decouples the user from control of individual vehicles, eliminating human limits on the size of the system, and uses a non-iterative sequence of algorithms that permit easy estimation of how computational complexity scales. The Hungarian algorithm used to solve a min-sum assignment with a one-task planning horizon becomes the limiting complexity, scaling at O(x3) where x is the larger number of vehicles or tasks in the assignment. This method is shown to have a unique property of creating non-intersecting routes which is used to drastically reduce the computational cost of deconflicting planned routes. Results from several demonstration flights are presented where a single user commands a system of 4 fixed-wing aircraft. The results confirm that autonomous flight of a large number of UAVs is a bona fide engineering sub-discipline, which is expected to be of interest to engineers who will find its utility in the aviation industry and in other emerging markets.

  9. Methanol intoxication: pathological changes of central nervous system (17 cases).

    Science.gov (United States)

    Karayel, Ferah; Turan, Arzu A; Sav, Aydin; Pakis, Isil; Akyildiz, Elif U; Ersoy, Gokhan

    2010-03-01

    The nervous system has increased susceptibility for methanol intoxication. The aim of this study is to investigate various central nervous system lesions of methanol intoxication in 17 cases autopsied in the mortuary department of the Council of Forensic Medicine in Istanbul, Turkey. The reasons of methanol intoxication in the cases was likely the unwitting ingestion of methanol while drinking illegal alcohol. Survival times ranged from several hours to days. In 8 cases (47%), cerebral edema and in 9 cases (53%) at occipital, temporal and parietal cortex, basal ganglia and pons, petechial bleeding was observed. In addition to these findings, hemorrhagic necrosis were observed in thalamus, putamen, and globus pallidus in 5 cases (29.4%) and, in cerebral cortex in another 3 cases (17.6%). In 3 of the cases (17.6%) in which cerebral edema was found, herniation findings accompanied to the situation and in 2 cases (11.7%), pons bleeding was observed. Around the basal ganglia, in 2 of the cases with hemorrhagic necrosis, the situation ended with a ventricular compression. In 7 cases (41%), the associated findings of chronic ischemic changes in cortical neurons, lacunae formation, degeneration of granular cell layer of the cerebellum, and reactive gliosis were considered as the results of chronic alcoholism.

  10. Glycosaminoglycans and Glycomimetics in the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Dáire Rowlands

    2015-02-01

    Full Text Available With recent advances in the construction of synthetic glycans, selective targeting of the extracellular matrix (ECM as a potential treatment for a wide range of diseases has become increasingly popular. The use of compounds that mimic the structure or bioactive function of carbohydrate structures has been termed glycomimetics. These compounds are mostly synthetic glycans or glycan-binding constructs which manipulate cellular interactions. Glycosaminoglycans (GAGs are major components of the ECM and exist as a diverse array of differentially sulphated disaccharide units. In the central nervous system (CNS, they are expressed by both neurons and glia and are crucial for brain development and brain homeostasis. The inherent diversity of GAGs make them an essential biological tool for regulating a complex range of cellular processes such as plasticity, cell interactions and inflammation. They are also involved in the pathologies of various neurological disorders, such as glial scar formation and psychiatric illnesses. It is this diversity of functions and potential for selective interventions which makes GAGs a tempting target. In this review, we shall describe the molecular make-up of GAGs and their incorporation into the ECM of the CNS. We shall highlight the different glycomimetic strategies that are currently being used in the nervous system. Finally, we shall discuss some possible targets in neurological disorders that may be addressed using glycomimetics.

  11. Investigation of bubble behaviours in wet central heating systems

    Directory of Open Access Journals (Sweden)

    Shefik Ali

    2014-03-01

    Full Text Available A series of experimental measurements has been conducted in order to investigate the bubble behaviours through the horizontal pipe line of the domestic wet central heating systems. Obtained results exposed the effect of 90 degree bend, buoyancy forces on bubbly two phase flow patterns and effect of velocity on void fractions and bubble diameters. Distance chosen for the first sight glass (HSG0 was sufficient enough to note the effect of 90 degree bend on void fraction patterns. Due to the effect of 90 degree bend, position of the peak void fractions across the pipe section lowers, with an increase in bulk fluid velocity. Bubbles tend to flow for longer distance at the bottom of the pipe section. Buoyancy force effect is demonstrated with figures for highest bulk fluid velocity at three different positions. Analysis of four different flow rates at two different saturation ratios show reduction for average bubble diameters and void fractions when bulk fluid velocity increases. An attempt to predict bubble dissolution rates across the horizontal pipeline of the system is made, however results show some uncertainties.

  12. Investigation of bubble behaviours in wet central heating systems

    Science.gov (United States)

    Shefik, Ali; Ge, Yunting

    2014-03-01

    A series of experimental measurements has been conducted in order to investigate the bubble behaviours through the horizontal pipe line of the domestic wet central heating systems. Obtained results exposed the effect of 90 degree bend, buoyancy forces on bubbly two phase flow patterns and effect of velocity on void fractions and bubble diameters. Distance chosen for the first sight glass (HSG0) was sufficient enough to note the effect of 90 degree bend on void fraction patterns. Due to the effect of 90 degree bend, position of the peak void fractions across the pipe section lowers, with an increase in bulk fluid velocity. Bubbles tend to flow for longer distance at the bottom of the pipe section. Buoyancy force effect is demonstrated with figures for highest bulk fluid velocity at three different positions. Analysis of four different flow rates at two different saturation ratios show reduction for average bubble diameters and void fractions when bulk fluid velocity increases. An attempt to predict bubble dissolution rates across the horizontal pipeline of the system is made, however results show some uncertainties.

  13. Signaling mechanisms regulating myelination in the central nervous system

    Institute of Scientific and Technical Information of China (English)

    Jared T.Ahrendsen; Wendy Macklin

    2013-01-01

    The precise and coordinated production of myelin is essential for proper development and function of the nervous system.Diseases that disrupt myelin,including multiple sclerosis,cause significant functional disability.Current treatment aims to reduce the inflammatory component of the disease,thereby preventing damage resulting from demyelination.However,therapies are not yet available to improve natural repair processes after damage has already occurred.A thorough understanding of the signaling mechanisms that regulate myelin generation will improve our ability to enhance repair.In this review,we summarize the positive and negative regulators of myelination,focusing primarily on central nervous system myelination.Axon-derived signals,extracellular signals from both diffusible factors and the extracellular matrix,and intracellular signaling pathways within myelinating oligodendrocytes are discussed.Much is known about the positive regulators that drive myelination,while less is known about the negative regulators that shift active myelination to myelin maintenance at the appropriate time.Therefore,we also provide new data on potential negative regulators of CNS myelination.

  14. The behaviour of REE and Zr-Hf fractionation in the volcanic waters of Nevado del Ruiz system (Colombia)

    Science.gov (United States)

    Inguaggiato, Claudio; Censi, Paolo; Zuddas, Pierpaolo; Makario Londoño, John; Chacón, Zoraida; Alzate, Diego; Brusca, Lorenzo; D'Alessandro, Walter

    2015-04-01

    The geochemical behaviour of Rare Earth Element (REE), Zr and Hf have been investigated in the thermal waters of Nevado del Ruiz volcanic system. These fluids are characterised by a wide range of pH ranging between 1.0 and 8.8. The acidic waters are sulphate dominated with different Cl/SO4 ratios. The Nevado del Ruiz waters allowed to investigate the behaviour of investigated elements in a wide spectrum of pH and chemical composition of water. The important role of the pH and the ionic complexes have been evidenced in the distribution of REE, Zr and Hf in the aqueous phase. The pH rules the precipitation of authigenic oxyhydroxides of Fe, Al producing changes in REE, Zr, Hf amount and strong anomalies of Cerium and Europium. Y-Ho and Zr-Hf (twin pairs) have different behaviour in strong acidic waters with respect to the water with higher pH. Yttrium and Ho have the same behaviour of Zr and Hf in waters with pH near neutral-to-neutral, showing super-chondritic ratios. The twin pairs showed to be sensitive to the co-precipitation and/or adsorption onto the surface of authigenic particulate suggesting an enhanced scavenging of Ho and Hf respect to Y and Zr, leading to super-chondritic ratios. In acidic waters a different behaviour of twin pairs occurs with chondritic Y/Ho ratios (reflecting the Y/Ho ratio of average local rock) and sub-chondritic Zr/Hf ratios. For the first time, Zr and Hf have been investigated in natural acidic fluids to understand the behaviour of these elements in extreme acidic conditions and different major anions chemistry. Zr/Hf molar ratio changes from 4.75 to 49.29 in water with pH<3.6. In strong acidic waters, a different fractionation of Zr and Hf have been recognised as function of major anion contents (Cl and SO4), suggesting the formation of complexes leading to sub-chondritic Zr/Hf molar ratios.

  15. System design package for the solar heating and cooling central data processing system

    Science.gov (United States)

    1978-01-01

    The central data processing system provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. Overall software system requirements were established for use in the central integration facility which transforms raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems.

  16. Hydrogeologic framework of the Wood River Valley aquifer system, south-central Idaho

    Science.gov (United States)

    Bartolino, James R.; Adkins, Candice B.

    2012-01-01

    The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Hailey, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system, which consists primarily of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on groundwater for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the groundwater resource. As part of an ongoing U.S. Geological Survey effort to characterize the groundwater resources of the Wood River Valley, this report describes the hydrogeologic framework of the Wood River Valley aquifer system. Although most of the Wood River Valley aquifer system is composed of Quaternary-age sediments and basalts of the Wood River Valley and its tributaries, older igneous, sedimentary, or metamorphic rocks that underlie these Quaternary deposits also are used for water supply. It is unclear to what extent these rocks are hydraulically connected to the main part of Wood River Valley aquifer system and thus whether they constitute separate aquifers. Paleozoic sedimentary rocks in and near the study area that produce water to wells and springs are the Phi Kappa and Trail Creek Formations (Ordovician and Silurian), the Milligen Formation (Devonian), and the Sun Valley Group including the Wood River Formation (Pennsylvanian-Permian) and the Dollarhide Formation (Permian). These sedimentary rocks are intruded by granitic rocks of the Late Cretaceous Idaho batholith. Eocene Challis Volcanic Group rocks overlie all of the older rocks (except where removed by erosion). Miocene Idavada Volcanics are found in the southern part of the study area. Most of these rocks have been folded, faulted, and

  17. Evolution of bilaterian central nervous systems: a single origin?

    Science.gov (United States)

    Holland, Linda Z; Carvalho, João E; Escriva, Hector; Laudet, Vincent; Schubert, Michael; Shimeld, Sebastian M; Yu, Jr-Kai

    2013-01-01

    The question of whether the ancestral bilaterian had a central nervous system (CNS) or a diffuse ectodermal nervous system has been hotly debated. Considerable evidence supports the theory that a CNS evolved just once. However, an alternative view proposes that the chordate CNS evolved from the ectodermal nerve net of a hemichordate-like ancestral deuterostome, implying independent evolution of the CNS in chordates and protostomes. To specify morphological divisions along the anterior/posterior axis, this ancestor used gene networks homologous to those patterning three organizing centers in the vertebrate brain: the anterior neural ridge, the zona limitans intrathalamica and the isthmic organizer, and subsequent evolution of the vertebrate brain involved elaboration of these ancestral signaling centers; however, all or part of these signaling centers were lost from the CNS of invertebrate chordates. The present review analyzes the evidence for and against these theories. The bulk of the evidence indicates that a CNS evolved just once - in the ancestral bilaterian. Importantly, in both protostomes and deuterostomes, the CNS represents a portion of a generally neurogenic ectoderm that is internalized and receives and integrates inputs from sensory cells in the remainder of the ectoderm. The expression patterns of genes involved in medio/lateral (dorso/ventral) patterning of the CNS are similar in protostomes and chordates; however, these genes are not similarly expressed in the ectoderm outside the CNS. Thus, their expression is a better criterion for CNS homologs than the expression of anterior/posterior patterning genes, many of which (for example, Hox genes) are similarly expressed both in the CNS and in the remainder of the ectoderm in many bilaterians. The evidence leaves hemichordates in an ambiguous position - either CNS centralization was lost to some extent at the base of the hemichordates, or even earlier, at the base of the hemichordates

  18. Kynurenines and Multiple Sclerosis: The Dialogue between the Immune System and the Central Nervous System

    OpenAIRE

    Cecilia Rajda; Zsófia Majláth; Dániel Pukoli; László Vécsei

    2015-01-01

    Multiple sclerosis is an inflammatory disease of the central nervous system, in which axonal transection takes place in parallel with acute inflammation to various, individual extents. The importance of the kynurenine pathway in the physiological functions and pathological processes of the nervous system has been extensively investigated, but it has additionally been implicated as having a regulatory function in the immune system. Alterations in the kynurenine pathway have been described in ...

  19. Applications of Nanotechnology to the Central Nervous System

    Science.gov (United States)

    Blumling, James P., II

    Nanotechnology and nanomaterials, in general, have become prominent areas of academic research. The ability to engineer at the nano scale is critical to the advancement of the physical and medical sciences. In the realm of physical sciences, the applications are clear: smaller circuitry, more powerful computers, higher resolution intruments. However, the potential impact in the fields of biology and medicine are perhaps even grander. The implementation of novel nanodevices is of paramount importance to the advancement of drug delivery, molecular detection, and cellular manipulation. The work presented in this thesis focuses on the development of nanotechnology for applications in neuroscience. The nervous system provides unique challenges and opportunities for nanoscale research. This thesis discusses some background in nanotechnological applications to the central nervous system and details: (1) The development of a novel calcium nanosenser for use in neurons and astrocytes. We implemented the calcium responsive component of Dr. Roger Tsien's Cameleon sensor, a calmodulin-M13 fusion, in the first quantum dot-based calcium sensor. (2) The exploration of cell-penetrating peptides as a delivery mechanism for nanoparticles to cells of the nervous system. We investigated the application of polyarginine sequences to rat primary cortical astrocytes in order to assess their efficacy in a terminally differentiated neural cell line. (3) The development of a cheap, biocompatible alternative to quantum dots for nanosensor and imaging applications. We utilized a positively charged co-matrix to promote the encapsulation of free sulforhodamine B in silica nanoparticles, a departure from conventional reactive dye coupling to silica matrices. While other methods have been invoked to trap dye not directly coupled to silica, they rely on positively charged dyes that typically have a low quantum yield and are not extensively tested biologically, or they implement reactive dyes bound

  20. RAMI analysis of the ITER Central Safety System

    International Nuclear Information System (INIS)

    Highlights: • We performed the functional analysis of the ITER CSS. • We performed a failure mode analysis of the ITER CSS. • We estimated the reliability and availability of the ITER CSS. • The ITER RAMI approach was applied to the ITER CSS for technical risk control in the design phase. - Abstract: ITER is the first worldwide international project aiming to design a facility to produce nuclear fusion energy. The technical requirements of its plant systems have been established in the ITER Project Baseline. In the project, the Reliability, Availability, Maintainability and Inspectability (RAMI) approach has been adopted for technical risk control to help aid the design of the components in preparation for operation and maintenance. A RAMI analysis was performed on the conceptual design of the ITER Central Safety System (CSS). A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 2 main functions and 20 sub-functions. These functions were described using the IDEF0 method. Reliability block diagrams were prepared to estimate the reliability and availability of each function under the stipulated operating conditions. Initial and expected scenarios were analyzed to define risk-mitigation actions. The inherent availability of the ITER CSS expected after implementation of mitigation actions was calculated to be 99.80% over 2 years, which is the typical interval of the scheduled maintenance cycles. This is consistent with the project required value of 99.9 ± 0.1%. A Failure Modes, Effects and Criticality Analysis was performed with criticality charts highlighting the risk level of the different failure modes with regard to their probability of occurrence and their effects on the availability of the plasma operation. This analysis defined when risk mitigation actions were required in terms of design, testing, operation procedures and/or maintenance to reduce the risk levels and increase the availability of the

  1. Central nervous control of energy and glucose balance: Focus on the central melanocortin system

    Science.gov (United States)

    Studies have suggested that manipulations of the central melanocortin circuitry by pharmacological agents produce robust effects on the regulation of body weight and glucose homeostasis. In this review, we discuss recent findings from genetic mouse models that have further established the physiologi...

  2. Sedimentary responses to sub-aerial felsic volcanism from the Late Devonian-Early Carboniferous northern Macalister Synclinorium, southeastern Australia

    Science.gov (United States)

    O'Halloran, G. J.; Gaul, A. J.

    1997-04-01

    Active sub-aerial volcanism has the capability to rapidly alter both the topographic and drainage characteristics of a landscape, and thus fundamentally influence resulting sedimentary facies. Relationships between sedimentation and volcanism are explored in this paper, via an investigation of the stratigraphy and early depositional history of the Upper Devonian volcano-sedimentary units of the northern Macalister Synclinorium, east-central Victoria. Complex interfingering relationships exist between sub-aerial felsic volcanic successions (Rose River Volcanics) and alluvial, fluvial and lacustrine sedimentary units (the Bindaree and Howitt Spur Formations). A depositional model is presented for these units, in which the Rose River Volcanics, an outflow (ignimbritic plateau) facies of the Tolmie caldera complex to the north, co-existed with a series of volcaniclastic alluvial fans and freshwater lakes. A dacitic volcanic centre (Refrigerator Gap Dacite) appears to have developed somewhat separately to the south, in the Jamieson River area. These lower successions of the northern Macalister Synclinorium record an episode of sedimentation in close proximity to an active felsic volcanic terrain, and in a landscape of significant topographic relief. The conglomerates of the Bindaree Formation, in particular, record the supply of abundant felsic volcanic detritus via high-gradient proximal alluvial stream systems. Comparisons can be made with sedimentological processes operating during deposition of overlying sedimentary successions, where influences by primary volcanic activity were less important. Well defined channel geometry successions and a diversification in clast and grain types within these younger units indicate ongoing headward erosion into metasedimentary basement rocks, and deposition within lower-gradient, higher-order stream systems.

  3. Role of crustal assimilation and basement compositions in the petrogenesis of differentiated intraplate volcanic rocks: a case study from the Siebengebirge Volcanic Field, Germany

    Science.gov (United States)

    Schneider, K. P.; Kirchenbaur, M.; Fonseca, R. O. C.; Kasper, H. U.; Münker, C.; Froitzheim, N.

    2016-06-01

    The Siebengebirge Volcanic Field (SVF) in western Germany is part of the Cenozoic Central European Volcanic Province. Amongst these volcanic fields, the relatively small SVF comprises the entire range from silica-undersaturated mafic lavas to both silica-undersaturated and silica-saturated differentiated lavas. Owing to this circumstance, the SVF represents a valuable study area representative of intraplate volcanism in Europe. Compositions of the felsic lavas can shed some new light on differentiation of intraplate magmas and on the extent and composition of potential crustal assimilation processes. In this study, we provide detailed petrographic and geochemical data for various differentiated SVF lavas, including major and trace element concentrations as well as Sr-Nd-Hf-Pb isotope compositions. Samples include tephriphonolites, latites, and trachytes with SiO2 contents ranging between 53 and 66 wt%. If compared to previously published compositions of mafic SVF lavas, relatively unradiogenic 143Nd/144Nd and 176Hf/177Hf coupled with radiogenic 87Sr/86Sr and 207Pb/204Pb lead to the interpretation that the differentiated volcanic rocks have assimilated significant amounts of lower crustal mafic granulites like the ones found as xenoliths in the nearby Eifel volcanic field. These crustal contaminants should possess unradiogenic 143Nd/144Nd and 176Hf/177Hf, radiogenic 87Sr/86Sr, and highly radiogenic 207Pb/204Pb compositions requiring the presence of ancient components in the central European lower crust that are not sampled on the surface. Using energy-constrained assimilation-fractional crystallisation (EC-AFC) model calculations, differentiation of the SVF lithologies can be modelled by approximately 39-47 % fractional crystallisation and 6-15 % crustal assimilation. Notably, the transition from silica-undersaturated to silica-saturated compositions of many felsic lavas in the SVF that is difficult to account for in closed-system models is also well explained by

  4. Boundary of the southwestern Nevada volcanic field from Laczniak and others (1996), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set defines the boundary of the southwestern Nevada volcanic field (SWNVF), an area of thick, regionally distributed volcanic rocks within the...

  5. Diffusion imaging in pediatric central nervous system infections

    International Nuclear Information System (INIS)

    Our purpose was to investigate the role of diffusion imaging (DI) in central nervous system (CNS) infections in pediatric patients. It was anticipated that DI would be more sensitive than conventional MRI in the detection of the infarctive complications of infection, and possibly, in the detection of the infectious process as well. Seventeen pediatric patients, eight having meningitis'' five with herpes encephalitis, three with brain abscess or cerebritis and one with sepsis, were evaluated at 1.5-T with DI. All herpes patients had positive DI at the site of herpetic involvement, and two had the addition of watershed infarctions. DI demonstrated more lesions in three of the four cases of herpetic encephalitis. Half the meningitis cases had watershed infarction where DI was better and half had vasculitic infarctions in which DI was equal to or better than conventional MRI. Diffusion imaging was more sensitive than conventional MRI alone in detection of changes due to infections and ischemic lesions, but did not differentiate between them by DI or apparent diffusion coefficient (ADC), although anatomic distribution of lesions proved useful. (orig.)

  6. Diffusion imaging in pediatric central nervous system infections

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, J. [Dept. de Imagiologia, Hospital Geral De Santo Antonio, Porto (Portugal); Zimmerman, R.A.; Haselgrove, J.C.; Bilaniuk, L.T.; Hunter, J.V. [Dept. of Radiology, Children' s Hospital of Philadelphia, PA (United States)

    2001-12-01

    Our purpose was to investigate the role of diffusion imaging (DI) in central nervous system (CNS) infections in pediatric patients. It was anticipated that DI would be more sensitive than conventional MRI in the detection of the infarctive complications of infection, and possibly, in the detection of the infectious process as well. Seventeen pediatric patients, eight having meningitis'' five with herpes encephalitis, three with brain abscess or cerebritis and one with sepsis, were evaluated at 1.5-T with DI. All herpes patients had positive DI at the site of herpetic involvement, and two had the addition of watershed infarctions. DI demonstrated more lesions in three of the four cases of herpetic encephalitis. Half the meningitis cases had watershed infarction where DI was better and half had vasculitic infarctions in which DI was equal to or better than conventional MRI. Diffusion imaging was more sensitive than conventional MRI alone in detection of changes due to infections and ischemic lesions, but did not differentiate between them by DI or apparent diffusion coefficient (ADC), although anatomic distribution of lesions proved useful. (orig.)

  7. Frequency of central nervous system tumors in delta region, Egypt

    Directory of Open Access Journals (Sweden)

    Khaled R Zalata

    2011-01-01

    Full Text Available Introduction and Aim of Work: Central nervous system (CNS tumors represent a major public health problem, and their epidemiological data in Egypt have been rather incomplete except for some regional reports. There are no available frequency-based data on CNS tumors in our locality. The objective of this study was to estimate the frequency of CNS tumors in east delta region, Egypt. Materials and Methods: The data were collected during the 8-year period from January 1999 to December 2007 from Pathology Department, Mansoura University, and other referred pathology labs. Examination of HandE stained sections from retrieved paraffin blocks were done in all cases for histopathologic categorization of C.N.S. tumors. Immunohistochemical studies were applied to confirm final histopathologic diagnosis in problematic cases. Results: Intracranial tumors represented 86.7% of cases in comparison to only 13.3% for spinal tumors. Gliomas were the CNS tumors of the highest frequency (35.2%, followed by meningioma (25.6%, pituitary adenoma (11.6% and nerve sheath tumors (6.6%. 10.25% of tumors were of children <15 years. Conclusion: This study provides the largest series of the relative frequency of CNS tumors in Delta region in Egypt till now and may help to give insight into the epidemiology of CNS tumors in our locality.

  8. BANJARESE GREETINGS SYSTEM IN DISTRICT KAPUAS OF CENTRAL KALIMANTAN

    Directory of Open Access Journals (Sweden)

    Indra Perdana

    2015-12-01

    Full Text Available Research on the study of the use of greeting in Banjarese which stay in Kapuas District of Central Borneo.This Research focused to describe the greeting word used by the people, particularly the greeting word in Banjarese used by the first generetion in Kapuas. The research method used is descriptive qualitative. Data collection by observation with a look at, involved notes. Sources of research data used is the preference of all speech that is displayed by 1 Aged over 30 years, 2 Native language studied. 3 Knowing its own culture, 4 The Banjarese are the first generation derived from Banjarmasin, 5 The Banjarese who had lived in Kapuas. Based on this research shows 1 Greetings kinship to greet our parents (father + mother → (+ Uma Abah; Greetings kinship parents to greet our father and mother (grandfather + grandmother → (kai + nini; Greetings kinship to greet parents our grandparents are corrected; Greetings kinship to greet both parents protested was waring; Greetings kinship to say hello (brother + sister → (kaka + ading. Greetings kinship to say hello if our children have children (grandchildren → (grandchildren; Greetings kinship to say hello if we have children and grandchildren is a great-grandfather. And 2 The system of daily greeting, to call people who may be called ikam lifetime, lives. I use the word, unda to appoint themselves. As for honor or call older used the word pian, and said ulun to appoint its own self.

  9. Eosinophilic vasculitis in an isolated central nervous system distribution

    Science.gov (United States)

    Sommerville, R Brian; Noble, James M; Vonsattel, Jean Paul; Delapaz, Robert; Wright, Clinton B

    2009-01-01

    Eosinophilic vasculitis has been described as part of the Churg–Strauss syndrome, but affects the central nervous system (CNS) in <10% of cases. A 39-year-old woman with a history of migraine without aura presented to an institution in an acute confusional state with concurrent headache and left-sided weakness. Laboratory evaluation showed an increased cerebrospinal fluid (CSF) protein level, but otherwise unremarkable serologies. Magnetic resonance imaging showed bifrontal polar gyral-enhancing brain lesions. Her symptoms resolved over two weeks without residual deficits. Eighteen months later the patient presented with similar symptoms and neuroradiological findings showed involvement of territories different from those in her first episode. Brain biopsy showed transmural, predominantly eosinophilic, inflammatory infiltrates and fibrinoid necrosis without granulomas. She improved when treated with corticosteroids. To our knowledge, this is the first case of non-granulomatous eosinophilic vasculitis isolated to the CNS. No aetiology for this patient’s primary CNS eosinophilic vasculitis has yet been identified. PMID:21686608

  10. Cell replacement therapy for central nervous system diseases

    Institute of Scientific and Technical Information of China (English)

    Danju Tso; Randall D. McKinnon

    2015-01-01

    The brain and spinal cord can not replace neurons or supporting glia that are lost through trau-matic injury or disease. In pre-clinical studies, however, neural stem and progenitor cell transplants can promote functional recovery. Thus the central nervous system is repair competent but lacks endogenous stem cell resources. To make transplants clinically feasible, this ifeld needs a source of histocompatible, ethically acceptable and non-tumorgenic cells. One strategy to generate pa-tient-speciifc replacement cells is to reprogram autologous cells such as ifbroblasts into pluripotent stem cells which can then be differentiated into the required cell grafts. However, the utility of pluripotent cell derived grafts is limited since they can retain founder cells with intrinsic neoplastic potential. A recent extension of this technology directly reprograms ifbroblasts into the ifnal graft-able cells without an induced pluripotent stem cell intermediate, avoiding the pluripotent caveat. For both types of reprogramming the conversion efficiency is very low resulting in the need to amplify the cells in culture which can lead to chromosomal instability and neoplasia. Thus to make reprogramming biology clinically feasible, we must improve the efifciency. The ultimate source of replacement cells may reside in directly reprogramming accessible cells within the brain.

  11. Microparticles: A New Perspective in Central Nervous System Disorders

    Directory of Open Access Journals (Sweden)

    Stephanie M. Schindler

    2014-01-01

    Full Text Available Microparticles (MPs are a heterogeneous population of small cell-derived vesicles, ranging in size from 0.1 to 1 μm. They contain a variety of bioactive molecules, including proteins, biolipids, and nucleic acids, which can be transferred between cells without direct cell-to-cell contact. Consequently, MPs represent a novel form of intercellular communication, which could play a role in both physiological and pathological processes. Growing evidence indicates that circulating MPs contribute to the development of cancer, inflammation, and autoimmune and cardiovascular diseases. Most cell types of the central nervous system (CNS have also been shown to release MPs, which could be important for neurodevelopment, CNS maintenance, and pathologies. In disease, levels of certain MPs appear elevated; therefore, they may serve as biomarkers allowing for the development of new diagnostic tools for detecting the early stages of CNS pathologies. Quantification and characterization of MPs could also provide useful information for making decisions on treatment options and for monitoring success of therapies, particularly for such difficult-to-treat diseases as cerebral malaria, multiple sclerosis, and Alzheimer’s disease. Overall, studies on MPs in the CNS represent a novel area of research, which promises to expand the knowledge on the mechanisms governing some of the physiological and pathophysiological processes of the CNS.

  12. Fractal Structure and Entropy Production within the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Andrew J. E. Seely

    2014-08-01

    Full Text Available Our goal is to explore the relationship between two traditionally unrelated concepts, fractal structure and entropy production, evaluating both within the central nervous system (CNS. Fractals are temporal or spatial structures with self-similarity across scales of measurement; whereas entropy production represents the necessary exportation of entropy to our environment that comes with metabolism and life. Fractals may be measured by their fractal dimension; and human entropy production may be estimated by oxygen and glucose metabolism. In this paper, we observe fractal structures ubiquitously present in the CNS, and explore a hypothetical and unexplored link between fractal structure and entropy production, as measured by oxygen and glucose metabolism. Rapid increase in both fractal structures and metabolism occur with childhood and adolescent growth, followed by slow decrease during aging. Concomitant increases and decreases in fractal structure and metabolism occur with cancer vs. Alzheimer’s and multiple sclerosis, respectively. In addition to fractals being related to entropy production, we hypothesize that the emergence of fractal structures spontaneously occurs because a fractal is more efficient at dissipating energy gradients, thus maximizing entropy production. Experimental evaluation and further understanding of limitations and necessary conditions are indicated to address broad scientific and clinical implications of this work.

  13. Corticosteroid-related central nervous system side effects

    Directory of Open Access Journals (Sweden)

    Miriam Ciriaco

    2013-01-01

    Full Text Available Corticosteroids have been used since the 50s as anti-inflammatory and immunosuppressive drugs for the treatment of several pathologies such as asthma, allergy, rheumatoid arthritis, and dermatological disorders. Corticosteroids have three principal mechanisms of action: 1 inhibit the synthesis of inflammatory proteins blocking NF-kB, 2 induce the expression of anti-inflammatory proteins by IkB and MAPK phosphatase I, and 3 inhibit 5-lipoxygenase and cyclooxygenase-2. The efficacy of glucocorticoids in alleviating inflammatory disorders results from the pleiotropic effects of the glucocorticoid receptors on multiple signaling pathways. However, they have adverse effects: Growth retardation in children, immunosuppression, hypertension, hyperglycemia, inhibition of wound repair, osteoporosis, metabolic disturbances, glaucoma, and cataracts. Less is known about psychiatric or side effects on central nervous system, as catatonia, decreased concentration, agitation, insomnia, and abnormal behaviors, which are also often underestimated in clinical practice. The aim of this review is to highlight the correlation between the administration of corticosteroids and CNS adverse effects, giving a useful guide for prescribers including a more careful assessment of risk factors and encourage the use of safer doses of this class of drugs.

  14. Fetal central nervous system anomalies: fast MRI vs ultrasonography

    International Nuclear Information System (INIS)

    Objective: To evaluate the ability of fast MRI to detect fetal central nervous system (CNS) anomalies and to compare its performance with that of prenatal ultrasonography (US). Methods Forty-eight pregnant women were detected by conventional prenatal US and MRI. Twenty-two fetuses with CNS anomalies were conformed by autopsy and follow-up. The MR and US appearances of fetal CNS structure were compared to each other and to that of autopsy. Results: A total of 26 CNS anomalies were identified by autopsy (n=17) and follow-up (n=9) including anencephaly (n=6), rachischisis (n=2), encephalocele (n=3), congenital hydrocephalus (n=7), alobar holoprosencephaly (n=1), porencephalia (n=3), arachnoid cyst (n=2) and choroids plexus cyst (n=2). US diagnosed 24 CNS anomalies, the correct diagnostic rate was 92.3%, the false-positive rate was 3.8%, the missed-diagnostic rate was 3.8%. MRI diagnosed 23 CNS anomalies, the correct-diagnostic rate was 88.5%, the false-positive rate was 3.8% ,the missed-diagnostic rate was 7.7%. There was no difference between US and MRI (P>0.05), but MRI have larger FOV, higher tissues resolution, and can demonstrate gray-white matter in detail. Conclusions: MR imaging has a similar sensitivity to that of US in the detection of fetal CNS anomalies. (authors)

  15. Comprehensive Craniospinal Radiation for Controlling Central Nervous System Leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Gary V.; Shihadeh, Ferial [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kantarjian, Hagop [Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Allen, Pamela [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rondon, Gabriela; Kebriaei, Partow [Department of Stem Cell Transplantation, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); O' Brien, Susan [Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kedir, Aziza; Said, Mustefa; Grant, Jonathan D. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Thomas, Deborah A. [Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gidley, Paul W. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Arzu, Isidora; Pinnix, Chelsea; Reed, Valerie [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dabaja, Bouthaina S., E-mail: bdabaja@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-12-01

    Purpose: To determine the benefit of radiation therapy (RT) in resolution of neurologic symptoms and deficits and whether the type of RT fields influences central nervous system (CNS) control in adults with CNS leukemia. Methods and Materials: A total of 163 adults from 1996 to 2012 were retrospectively analyzed. Potential associations between use of radiation and outcome were investigated by univariate and multivariate analysis. Results: The median survival time was 3.8 months after RT. Common presenting symptoms were headache in 79 patients (49%), cranial nerve VII deficit in 46 (28%), and cranial nerve II deficit in 44 (27%). RT was delivered to the base of skull in 48 patients (29%), to the whole brain (WB) in 67 (41%), and to the craniospinal axis (CS) in 48 (29%). Among 149 patients with a total of 233 deficits, resolution was observed in 34 deficits (15%), improvement in 126 deficits (54%), stability in 34 deficits (15%), and progression in 39 deficits (17%). The 12-month CNS progression-free survival was 77% among those receiving CS/WB and 51% among those receiving base of skull RT (P=.02). On multivariate analysis, patients who did not undergo stem cell transplantation after RT and base of skull RT were associated with worse CNS progression-free survival. Conclusions: Improvement or resolution of symptoms occurred in two thirds of deficits after RT. Comprehensive radiation to the WB or CS seems to offer a better outcome, especially in isolated CNS involvement.

  16. Cholesterol: Its Regulation and Role in Central Nervous System Disorders

    Directory of Open Access Journals (Sweden)

    Matthias Orth

    2012-01-01

    Full Text Available Cholesterol is a major constituent of the human brain, and the brain is the most cholesterol-rich organ. Numerous lipoprotein receptors and apolipoproteins are expressed in the brain. Cholesterol is tightly regulated between the major brain cells and is essential for normal brain development. The metabolism of brain cholesterol differs markedly from that of other tissues. Brain cholesterol is primarily derived by de novo synthesis and the blood brain barrier prevents the uptake of lipoprotein cholesterol from the circulation. Defects in cholesterol metabolism lead to structural and functional central nervous system diseases such as Smith-Lemli-Opitz syndrome, Niemann-Pick type C disease, and Alzheimer’s disease. These diseases affect different metabolic pathways (cholesterol biosynthesis, lipid transport and lipoprotein assembly, apolipoproteins, lipoprotein receptors, and signaling molecules. We review the metabolic pathways of cholesterol in the CNS and its cell-specific and microdomain-specific interaction with other pathways such as the amyloid precursor protein and discuss potential treatment strategies as well as the effects of the widespread use of LDL cholesterol-lowering drugs on brain functions.

  17. Drug/radiation interactions and central nervous system injury

    International Nuclear Information System (INIS)

    Central nervous system (CNS) injury caused by combined treatment with cranial radiation therapy (CRT) and chemotherapy is a complicated and difficult problem. Interactions between the two modalities at the cellular level, the effect of treatment sequencing, and chemotherapy and RT dosages are all poorly understood. While this is generally true and applicable to toxicities expressed in multiple organs and tissue types, it is particularly true for the brain. There are many clinical descriptions and situations that strongly implicate an enhanced neurotoxic potential for combined treatment compared to either therapy alone; there is a paucity of definitive experimental evidence, however, and few animal models that can be used to elucidate the nature and pathophysiology of this clinical association. This paper addresses the neurotoxic potential of a specific chemotherapeutic drug when combined with CRT; outlines whose drugs known to cause CNS injury when combined with CRT. Although many of the clinical situations are complicated because multiple cytotoxic agents have been used, usually only one is thought to contribute to the CNS injury. The authors discuss each drug separately

  18. Imaging features of central nervous system fungal infections

    Directory of Open Access Journals (Sweden)

    Jain Krishan

    2007-01-01

    Full Text Available Fungal infections of the central nervous system (CNS are rare in the general population and are invariably secondary to primary focus elsewhere, usually in the lung or intestine. Except for people with longstanding diabetes, they are most frequently encountered in immunocompromised patients such as those with acquired immunodeficiency syndrome or after organ transplantation. Due to the lack of inflammatory response, neuroradiological findings are often nonspecific and are frequently mistaken for tuberculous meningitis, pyogenic abscess or brain tumor. Intracranial fungal infections are being identified more frequently due to the increased incidence of AIDS patients, better radiological investigations, more sensitive microbiological techniques and better critical care of moribund patients. Although almost any fungus may cause encephalitis, cryptococcal meningoencephalitis is most frequently seen, followed by aspergillosis and candidiasis. The biology, epidemiology and imaging features of the common fungal infections of the CNS will be reviewed. The radiographic appearance alone is often not specific, but the combination of the appropriate clinical setting along with computed tomography or magnetic resonance may help to suggest the correct diagnosis.

  19. Low-profile heliostat design for solar central receiver systems

    Science.gov (United States)

    Fourakis, E.; Severson, A. M.

    1977-01-01

    Heliostat designs intended to reduce costs and the effect of adverse wind loads on the devices were developed. Included was the low-profile heliostat consisting of a stiff frame with sectional focusing reflectors coupled together to turn as a unit. The entire frame is arranged to turn angularly about a center point. The ability of the heliostat to rotate about both the vertical and horizontal axes permits a central computer control system to continuously aim the sun's reflection onto a selected target. An engineering model of the basic device was built and is being tested. Control and mirror parameters, such as roughness and need for fine aiming, are being studied. The fabrication of these prototypes is in process. The model was also designed to test mirror focusing techniques, heliostat geometry, mechanical functioning, and tracking control. The model can be easily relocated to test mirror imaging on a tower from various directions. In addition to steering and aiming studies, the tests include the effects of temperature changes, wind gusting and weathering. The results of economic studies on this heliostat are also presented.

  20. Nanotechnologies for the study of the central nervous system.

    LENUS (Irish Health Repository)

    Ajetunmobi, A

    2014-12-01

    The impact of central nervous system (CNS) disorders on the human population is significant, contributing almost €800 billion in annual European healthcare costs. These disorders not only have a disabling social impact but also a crippling economic drain on resources. Developing novel therapeutic strategies for these disorders requires a better understanding of events that underlie mechanisms of neural circuit physiology. Studying the relationship between genetic expression, synapse development and circuit physiology in CNS function is a challenging task, involving simultaneous analysis of multiple parameters and the convergence of several disciplines and technological approaches. However, current gold-standard techniques used to study the CNS have limitations that pose unique challenges to furthering our understanding of functional CNS development. The recent advancement in nanotechnologies for biomedical applications has seen the emergence of nanoscience as a key enabling technology for delivering a translational bridge between basic and clinical research. In particular, the development of neuroimaging and electrophysiology tools to identify the aetiology and progression of CNS disorders have led to new insights in our understanding of CNS physiology and the development of novel diagnostic modalities for therapeutic intervention. This review focuses on the latest applications of these nanotechnologies for investigating CNS function and the improved diagnosis of CNS disorders.

  1. Cytokines and Myelination in the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Thomas Schmitz

    2008-01-01

    Full Text Available Myelin abnormalities that reflect damage to developing and mature brains are often found in neurological diseases with evidence of inflammatory infiltration and microglial activation. Many cytokines are virtually undetectable in the uninflamed central nervous system (CNS, so that their rapid induction and sustained elevation in immune and glial cells contributes to dysregulation of the inflammatory response and neural cell homeostasis. This results in aberrant neural cell development, cytotoxicity, and loss of the primary myelin-producing cells of the CNS, the oligodendrocytes. This article provides an overview of cytokine and chemokine activity in the CNS with relevance to clinical conditions of neonatal and adult demyelinating disease, brain trauma, and mental disorders with observed white matter defects. Experimental models that mimic human disease have been developed in order to study pathogenic and therapeutic mechanisms, but have shown mixed success in clinical application. However, genetically altered animals, and models of CNS inflammation and demyelination, have offered great insight into the complexities of neuroimmune interactions that impact oligodendrocyte function. The intracellular signaling pathways of selected cytokines have also been highlighted to illustrate current knowledge of receptor-mediated events. By learning to interpret the actions of cytokines and by improving methods to target appropriate predictors of disease risk selectively, a more comprehensive understanding of altered immunoregulation will aid in the development of advanced treatment options for patients with inflammatory white matter disorders.

  2. Solitary Fibrous Tumor of Central Nervous System: A Case Report.

    Science.gov (United States)

    Kim, Jang Hoon; Yang, Kook Hee; Yoon, Pyeong Ho; Kie, Jeong Hae

    2015-10-01

    Solitary fibrous tumor (SFT) is a rare neoplasm of mesenchymal origin, especially in the central nervous system (CNS). Reported herein is a case of SFT of CNS in a 63-year-old female patient who had confused mentality, without other neurological deficit. The brain MRI showed an ovoid mass in the right frontal lobe. The tumor was surgically removed grossly and totally, and the pathologic diagnosis was SFT. At 55 months after the surgery, the tumor recurred at the primary site and at an adjacent area. A second operation was thus done, and the tumor was again surgically removed grossly and totally. The pathologic diagnosis was the same as the previous, but the Ki-67 index was elevated. Ten months later, two small recurring tumors in the right frontal skull base were found in the follow-up MRI. It was decided that radiation therapy be done, and MRI was done again 3 months later. In the follow-up MRI, the size of the recurring mass was found to have decreased, and the patient did not manifest any significant symptom. Follow-up will again be done 18 months after the second surgery. PMID:26605270

  3. Materials directed to implants for repairing Central Nervous System

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Moreno-Burriel, B.; Chinarro, E.

    2014-07-01

    Central Nervous System (CNS) can be damaged by a wide range of injuries and disorders which entail permanent disability in some cases. Moreover, CNS repairing process presents some complications. The natural repair mechanism, which consists on the glial scar formation, is triggered by the inflammatory process. Molecules delivered during these processes, inflammation and glial scar formation as well as oxygen and glucose deficiencies due to the injury, create an inhibitory environment for axon regeneration and remyelination which is known as secondary injury. Biomaterials are taking up an even more important role in repairing CNS. Physicochemical properties of some ceramic materials have inspired different applications to repair CNS as substrates, electrodes or molecule vehicles. Based on their biocompatibility, capability to neutralize reactive species involved in the inflammatory processes and their versatile processing to obtain scaffolds with different shapes and sizes, ceramics are a succulent offer in nervous tissue engineering. Furthermore, their possibilities have been increased with polymeric-ceramics composites development, which have given rise to new interesting horizon. (Author)

  4. Ventriculoperitoneal shunt for hydrocephalus caused by central nervous system metastasis.

    Science.gov (United States)

    Lee, Seung Hoon; Kong, Doo Sik; Seol, Ho Joon; Nam, Do-Hyun; Lee, Jung-Il

    2011-09-01

    The development of better diagnostic tools and therapeutic modalities has increased the incidence of central nervous system (CNS) metastasis in malignant tumor patients. Hydrocephalus can result from CNS metastasis and frustrate cancer treatment. The authors sought to investigate the outcomes and the roles of ventriculoperitoneal shunts (VPS) in patients with CNS metastasis. The medical records of 50 consecutive patients who underwent VPS for hydrocephalus related to CNS metastasis were analyzed retrospectively. Data included features of primary malignancies, CNS involvement, clinical course and surgical outcome. Median patient age was 55.0 years (range 25-77), and 30 female and 20 male patients were included in the study. At the time of VPS, 10 patients had parenchymal metastases only and 40 patients had leptomeningeal seeding (LMS). Symptom improvement was observed postoperatively in 40 patients (80%), mean Karnofsky performance status (KPS) scale change was from 37.8 to 46.0, and median survival from VPS was 3.0 months (2 days to 54 months). A ventricular opening pressure of >30 cmH(2)O (HR 6.44, 95% CI 1.26-32.9, P = 0.02) and further cancer treatment after VPS (HR 0.17, 95% CI 0.07-0.42, P Hydrocephalus in CNS metastasis requiring VPS is commonly associated with LMS. VPS is an effective palliative measure and an adequate cancer treatment after VPS may provide the best means of improving survival.

  5. Central nervous system infections in the intensive care unit

    Directory of Open Access Journals (Sweden)

    B. Vengamma

    2014-04-01

    Full Text Available Neurological infections constitute an uncommon, but important aetiological cause requiring admission to an intensive care unit (ICU. In addition, health-care associated neurological infections may develop in critically ill patients admitted to an ICU for other indications. Central nervous system infections can develop as complications in ICU patients including post-operative neurosurgical patients. While bacterial infections are the most common cause, mycobacterial and fungal infections are also frequently encountered. Delay in institution of specific treatment is considered to be the single most important poor prognostic factor. Empirical antibiotic therapy must be initiated while awaiting specific culture and sensitivity results. Choice of empirical antimicrobial therapy should take into consideration the most likely pathogens involved, locally prevalent drug-resistance patterns, underlying predisposing, co-morbid conditions, and other factors, such as age, immune status. Further, the antibiotic should adequately penetrate the blood-brain and blood- cerebrospinal fluid barriers. The presence of a focal collection of pus warrants immediate surgical drainage. Following strict aseptic precautions during surgery, hand-hygiene and care of catheters, devices constitute important preventive measures. A high index of clinical suspicion and aggressive efforts at identification of aetiological cause and early institution of specific treatment in patients with neurological infections can be life saving.

  6. Systematic review of central nervous system anomalies in incontinentia pigmenti

    Directory of Open Access Journals (Sweden)

    Minić Snežana

    2013-02-01

    Full Text Available Abstract The objective of this study was to present a systematic review of the central nervous system (CNS types of anomalies and to consider the possibility to include CNS anomalies in Incontinentia pigmenti (IP criteria. The analyzed literature data from 1,393 IP cases were from the period 1993–2012. CNS anomalies were diagnosed for 30.44% of the investigated IP patients. The total number of CNS types of anomalies per patient was 1.62. In the present study there was no significantly higher number of anomalies per patient in females than males. The most frequent CNS types of anomalies were seizures, motor impairment, mental retardation, and microcephaly. The most frequently registered CNS lesions found using brain imaging methods were brain infarcts or necrosis, brain atrophies, and corpus callosum lesions. IKBKG exon 4–10 deletion was present in 86.00% of genetically confirmed IP patients. The frequency of CNS anomalies, similar to the frequency of retinal anomalies in IP patients, concurrent with their severity, supports their recognition in the list of IP minor criteria.

  7. Intranasal treatment of central nervous system dysfunction in humans.

    Science.gov (United States)

    Chapman, Colin D; Frey, William H; Craft, Suzanne; Danielyan, Lusine; Hallschmid, Manfred; Schiöth, Helgi B; Benedict, Christian

    2013-10-01

    One of the most challenging problems facing modern medicine is how to deliver a given drug to a specific target at the exclusion of other regions. For example, a variety of compounds have beneficial effects within the central nervous system (CNS), but unwanted side effects in the periphery. For such compounds, traditional oral or intravenous drug delivery fails to provide benefit without cost. However, intranasal delivery is emerging as a noninvasive option for delivering drugs to the CNS with minimal peripheral exposure. Additionally, this method facilitates the delivery of large and/or charged therapeutics, which fail to effectively cross the blood-brain barrier (BBB). Thus, for a variety of growth factors, hormones, neuropeptides and therapeutics including insulin, oxytocin, orexin, and even stem cells, intranasal delivery is emerging as an efficient method of administration, and represents a promising therapeutic strategy for the treatment of diseases with CNS involvement, such as obesity, Alzheimer's disease, Parkinson's disease, Huntington's disease, depression, anxiety, autism spectrum disorders, seizures, drug addiction, eating disorders, and stroke. PMID:23135822

  8. [Dementia in Patients with Central Nervous System Mycosis].

    Science.gov (United States)

    Morita, Akihiko; Ishihara, Masaki; Konno, Michiko

    2016-04-01

    Central nervous system (CNS) mycosis is a potentially life-threatening but treatable neurological emergency. CNS mycoses progress slowly and are sometimes difficult to distinguish from dementia. Though most patients with CNS mycosis have an underlying disease, such as human immunodeficiency virus (HIV) infection, cancer, diabetes mellitus, and/or use of immunosuppressants, cryptococcosis can occur in non-immunosuppressed persons. One of the major difficulties in accurate diagnosis is to detect the pathogen in patients' cerebrospinal fluid (CSF) cultures. Thus, the clinical diagnosis is often made by combining circumstantial evidence, including mononuclear cell-dominant pleocytosis with low glucose and protein elevation in the CSF, as well as positive results from an antigen-based assay and a (1-3)-beta-D-glucan assay using plasma and/or CSF. Polymerase chain reaction (PCR)-based diagnostics, which are not performed as routine examinations and are mostly performed as part of academic research in Japan, are sensitive tools for the early diagnosis of CNS mycosis. Mognetic resonance imaging (MRI) is useful to assess the complications of fungal meningitis, such as abscess, infarction, and hydrocephalus. Clinicians should realize the advantages and disadvantages of these diagnostic tools. Early and accurate diagnosis, including identification of the particular fungal species, enables optimal antifungal treatment that produces good outcomes in patients with CNS mycosis. PMID:27056851

  9. Growth Cone Biomechanics in Peripheral and Central Nervous System Neurons

    Science.gov (United States)

    Urbach, Jeffrey; Koch, Daniel; Rosoff, Will; Geller, Herbert

    2012-02-01

    The growth cone, a highly motile structure at the tip of an axon, integrates information about the local environment and modulates outgrowth and guidance, but little is known about effects of external mechanical cues and internal mechanical forces on growth-cone mediated guidance. We have investigated neurite outgrowth, traction forces and cytoskeletal substrate coupling on soft elastic substrates for dorsal root ganglion (DRG) neurons (from the peripheral nervous system) and hippocampal neurons (from the central) to see how the mechanics of the microenvironment affect different populations. We find that the biomechanics of DRG neurons are dramatically different from hippocampal, with DRG neurons displaying relatively large, steady traction forces and maximal outgrowth and forces on substrates of intermediate stiffness, while hippocampal neurons display weak, intermittent forces and limited dependence of outgrowth and forces on substrate stiffness. DRG growth cones have slower rates of retrograde actin flow and higher density of localized paxillin (a protein associated with substrate adhesion complexes) compared to hippocampal neurons, suggesting that the difference in force generation is due to stronger adhesions and therefore stronger substrate coupling in DRG growth cones.

  10. Involvement of central nervous system in the schistosomiasis

    Directory of Open Access Journals (Sweden)

    Teresa Cristina de Abreu Ferrari

    2004-08-01

    Full Text Available The involvement of the central nervous system (CNS by schistosomes may or may not determine clinical manifestations. When symptomatic, neuroschistosomiasis (NS is one of the most severe presentations of schistosomal infection. Considering the symptomatic form, cerebral involvement is almost always due to Schistosoma japonicum and the spinal cord disease, caused by S. mansoni or S. haematobium. Available evidence suggests that NS depends basically on the presence of parasite eggs in the nervous tissue and on the host immune response. The patients with cerebral NS usually have the clinical manifestations of increased intracranial pressure associated with focal neurological signs; and those with schistosomal myeloradiculopathy (SMR present rapidly progressing symptoms of myelitis involving the lower cord, usually in association with the involvement of the cauda esquina roots. The diagnosis of cerebral NS is established by biopsy of the nervous tissue and SMR is usually diagnosed according to a clinical criterion. Antischistosomal drugs, corticosteroids and surgery are the resourses available for treating NS. The outcome is variable and is better in cerebral disease.

  11. [Dementia in Patients with Central Nervous System Mycosis].

    Science.gov (United States)

    Morita, Akihiko; Ishihara, Masaki; Konno, Michiko

    2016-04-01

    Central nervous system (CNS) mycosis is a potentially life-threatening but treatable neurological emergency. CNS mycoses progress slowly and are sometimes difficult to distinguish from dementia. Though most patients with CNS mycosis have an underlying disease, such as human immunodeficiency virus (HIV) infection, cancer, diabetes mellitus, and/or use of immunosuppressants, cryptococcosis can occur in non-immunosuppressed persons. One of the major difficulties in accurate diagnosis is to detect the pathogen in patients' cerebrospinal fluid (CSF) cultures. Thus, the clinical diagnosis is often made by combining circumstantial evidence, including mononuclear cell-dominant pleocytosis with low glucose and protein elevation in the CSF, as well as positive results from an antigen-based assay and a (1-3)-beta-D-glucan assay using plasma and/or CSF. Polymerase chain reaction (PCR)-based diagnostics, which are not performed as routine examinations and are mostly performed as part of academic research in Japan, are sensitive tools for the early diagnosis of CNS mycosis. Mognetic resonance imaging (MRI) is useful to assess the complications of fungal meningitis, such as abscess, infarction, and hydrocephalus. Clinicians should realize the advantages and disadvantages of these diagnostic tools. Early and accurate diagnosis, including identification of the particular fungal species, enables optimal antifungal treatment that produces good outcomes in patients with CNS mycosis.

  12. Pharmacokinetics and pharmacodynamics of antiretrovirals in the central nervous system.

    Science.gov (United States)

    Calcagno, Andrea; Di Perri, Giovanni; Bonora, Stefano

    2014-10-01

    HIV-positive patients may be effectively treated with highly active antiretroviral therapy and such a strategy is associated with striking immune recovery and viral load reduction to very low levels. Despite undeniable results, the central nervous system (CNS) is commonly affected during the course of HIV infection, with neurocognitive disorders being as prevalent as 20-50 % of treated subjects. This review discusses the pathophysiology of CNS infection by HIV and the barriers to efficacious control of such a mechanism, including the available data on compartmental drug penetration and on pharmacokinetic/pharmacodynamic relationships. In the reviewed articles, a high variability in drug transfer to the CNS is highlighted with several mechanisms as well as methodological issues potentially influencing the observed results. Nevirapine and zidovudine showed the highest cerebrospinal fluid (CSF) to plasma ratios, although target concentrations are currently unknown for the CNS. The use of the composite CSF concentration effectiveness score has been associated with better virological outcomes (lower HIV RNA) but has been inconsistently associated with neurocognitive outcomes. These findings support the CNS effectiveness of commonly used highly antiretroviral therapies. The use of antiretroviral drugs with increased CSF penetration and/or effectiveness in treating or preventing neurocognitive disorders however needs to be assessed in well-designed prospective studies.

  13. MRI in central nervous system infections: A simplified patterned approach

    Institute of Scientific and Technical Information of China (English)

    Krithika; Rangarajan; Chandan; J; Das; Atin; Kumar; Arun; Kumar; Gupta

    2014-01-01

    Recognition and characterization of central nervous system infections poses a formidable challenge to the neuro-radiologist.Imaging plays a vital role,the lesions typically being relatively inaccessible to tisue sampling.The results of an accurate diagnosis are endlessly re-warding,given the availability of excellent pharmaco-logical regimen.The availability of numerous magnetic resonance(MR)sequences which provide functional and molecular information is a powerful tool in the hands of the radiologist.However,the plethora of se-quences and the possibilities on each sequence is also intimidating,and often confusing as well as time con-suming.While a large number of reviews have already described in detail the possible imaging findings in each infection,we intend to classify infections based on their imaging characteristics.In this review we describe an algorithm for first classifying the imaging findings into patterns based on basic MR sequences(T1,T2 and enhancement pattern with Gadolinium),and then sub-classify them based on more advanced molecular and functional sequences(Diffusion,Perfusion,Susceptibili-ty imaging,MR Spectroscopy).This patterned approachis intended as a guide to radiologists in-training and in-practice for quickly narrowing their list of differentials when faced with a clinical challenge.The entire content of the article has also been summarised in the form of flow-charts for the purpose of quick reference.

  14. Consolidation and Centralization of Waste Operations Business Systems - 12319