Holocene glacier and climate variations in Vestfirðir, Iceland, from the modeling of Drangajökull ice cap

NASA Astrophysics Data System (ADS)

Anderson, Leif S.; Flowers, Gwenn E.; Jarosch, Alexander H.; Aðalgeirsdóttir, Guðfinna Th; Geirsdóttir, Áslaug; Miller, Gifford H.; Harning, David J.; Thorsteinsson, Thorsteinn; Magnússon, Eyjólfur; Pálsson, Finnur

2018-06-01

Drangajökull is a maritime ice cap located in northwest (Vestfirðir) Iceland. Drangajökull's evolution is therefore closely linked to atmospheric and ocean variability. In order to better constrain the Holocene climate and glacier history of Vestfirðir we model the past evolution of Drangajökull ice cap. Simulations from 10 ka to present are forced by general circulation model output, ice-core-based temperature reconstructions, and sea-surface temperature reconstructions. Based on these 10-thousand year simulations, Drangajökull did not persist through the Holocene. We estimate that air temperatures were 2.5-3.0 °C higher during the Holocene Thermal Maximum than the local 1960-1990 average. Simulations support Drangajökull's late Holocene inception between 2 and 1 ka, though intermittent ice likely occupied cirques as early as 2.6 ka. Drangajökull is primarily a Little Ice Age ice cap: it expanded between 1300 and 1750 CE, with the most rapid growth occurring between 1600 and 1750 CE. The maximum Holocene extent of Drangajökull occurred between 1700 and 1925 CE, despite the lowest late Holocene temperatures, occurring between 1650 and 1720 CE. Between 1700 and 1925 CE temperatures were likely 0.6-0.8 °C lower than the 1950-2015 reference temperature. The modern equilibrium line altitude (ELA) is bracketed by topographic thresholds: a 1 °C temperature increase from the modern ELA would eliminate the ice cap's accumulation area, while a reduction of 0.5 °C would lead to the rapid expansion of the ice cap across Vestfirðir. The proximity of Drangajökull to topographic thresholds may explain its late inception and rapid expansion during the Little Ice Age.

The geomorphology and ground penetrating radar survey results of the Múlajökull and Þjórsárjökull surge-type glaciers, central Iceland

NASA Astrophysics Data System (ADS)

Karušs, Jānis; Lamsters, Kristaps; Běrziņš, Dāvids

2015-04-01

Múlajökull and Þjórsárjökull are surge-type outlet glaciers of the Hofsjökull ice cap, central Iceland (Björnsson et al., 2003). The forefield of Múlajökull comprises the active drumlin field of more than 110 drumlins (Johnson et al., 2010; Jónsson et al., 2014) and therefore is an excellent area for studies of glacial geomorphology, subglacial topography and ice structures. This work describes preliminary results obtained during the expedition to Múlajökull and Þjórsárjökull glaciers in August, 2014. In the research ground penetrating radar (GPR) Zond 12-e was used. GPR measurements were performed on both outlet glaciers using 38 MHz and 75 MHz antenna systems. During data acquisition 2000 ns time window was used, while length of profiles was determined using GPS device Garmin GPS-76. In total approximately 3 km of GPR profiles were recorded. GPR signals propagation speed in glacier ice was determined using reflections from internal meltwater channels of glacier. In obtained radarogramms it was possible to trace reflections from the glacier bed till depth of approximately 144 m as well as numerous prominent reflections from internal meltwater channels of glacier. In one of the obtained radarogramms possible subglacial channel below Múlajökull glacier was identified. Also feature of subglacial topography that resembles drumlin was identified. The area of abundant infiltrated water was distinguished close to the ice margin in the radarogramm obtained on Þjórsárjökull suggesting successive supraglacial meltwater infiltration towards glacier margin. During the field work numerous radial crevasses, supraglacial channels and moulins were observed in the marginal zone of Múlajökull. The forefield of Múlajökull mainly consist of subglacial landforms (drumlins, flutes and crevasse-fill ridges), end moraines and sandur plains. Flutes and crevasse-fill ridges were found superimposed on drumlins in places. Till macrofabric was measured close to the surface of two drumlins and at one section on the slope of drumlin. The fabrics possess strong orientations parallel to the axis of drumlins, as well as glacial striations on the boulders exposed at the drumlin surface. These striations indicate glacier sliding over its bed during the termination of the last surge. References Björnsson, H., Pálsson, F., Sigurđsson, O., Flowers, G.E. 2003. Surges of glaciers in Iceland. Annals of Glaciology, 36, 82-90. Johnson, M.D., Schomacker, A., Benediktsson, Í.Ö., Geiger, A.J., Ferguson, A. 2010. Active drumlin field revealed at the margin of Múlajökull, Iceland: a surge-type glacier. Geology, 38, 943-946. Jónsson, S.A., Schomacker, A., Benediktsson, I.Ó., Ingólfsson, Ó., Johnson, M.D. 2014. The drumlin field and the geomorphology of the Múlajökull surge-type glacier, central Iceland. Geomorphology, 207, 213-220.

Buried glacier ice in southern Iceland and its wider significance

NASA Astrophysics Data System (ADS)

Everest, Jeremy; Bradwell, Tom

2003-06-01

Geo-electrical resistivity surveys have been carried out at recently deglaciated sites in front of three glaciers in southern Iceland: Skeiðarájökull, Hrútárjökull, and Virkisjökull. The results show the presence of old glacier ice beneath debris mantles of various thickness. We conclude that buried glacier ice has survived for at least 50 years at Virkisjökull and Hrútárjökull, and probably for over 200 years at Skeiðarájökull. Additional data from a further site have identified a discontinuous ice core within 18th-century jökulhlaup deposits. Photographic and lichenometric evidence show that the overlying debris has been relatively stable, and hence melting of the ice at all four sites is proceeding slowly due to the heat-shielding properties of the overburden. The geomorphic implications are pertinent when considering the potential longevity of buried ice. The possible implications for dating techniques, such as lichenometry, radiocarbon dating and cosmogenic surface-exposure dating are also important, as long-term readjustments of surface forms may lead to dating inaccuracy. Finally, it is recognised that landscape development in areas of stagnant ice topography may post-date initial deglaciation by a considerable degree.

Early Deglaciation of Drangajökull, Vestfirðir, Iceland: Smaller than Present by 9.2 ka

NASA Astrophysics Data System (ADS)

Harning, D.; Geirsdottir, A.; Miller, G. H.; Zalzal, K.

2016-12-01

The Holocene histories of Iceland's largest ice caps suggest rapid early Holocene deglaciation and disappearance by 9 ka, other than possible small remnants of Vatnajökull. The least documented is Drangajökull, Vestfirðir, NW Iceland, where our team has been working since 2010. A recent study claims Drangajökull behaved differently than the other Iceland ice caps, deglaciating much later, and persisting through the Holocene Thermal Maximum (HTM). We test this postulate through a suite of sediment cores from threshold lakes both proximal and distal to the ice cap's contemporary margin. Distal lakes document rapid early Holocene deglaciation across the southern highland plateau, with the northern margin of the ice cap reaching a size comparable to Drangajökull's contemporary limit by 10.3 ka. A proximal lake to the north records a transient readvance at 9.6 ka, likely in association with meltwater pulses from the disintegrating Laurentide Ice Sheet (LIS). Two other southeastern proximal lakes, whose catchments extend well beneath the modern ice cap, demonstrate that Drangajökull was already smaller than present before 9.2 ka. Supporting evidence for local early Holocene warmth is derived from biological summer temperature proxies in a lake record, with age control (tephra/14C) demonstrating continuous sediment accumulation from 10.3 ka to present. Peak warmth (HTM) inferred from elevated algal productivity occurred between 8.9 and 7.2 ka. The record of terrestrial warmth closely aligns with regional SST and precipitation records that together with lake sediment characteristics provide firm evidence that Drangajökull responded similarly to Iceland's other large ice caps. Drangajökull was smaller than its contemporary margin before 9.2 ka, and likely disappeared entirely during the warmer and drier summers between 9 and 7 ka, reforming in the Late Holocene.

Influence of Gígjökull on the Emplacement of the Lava Flow Produced by the 2010 Eruption of Eyjafjallajökull, Iceland, and the Flow's Effects on the Glacier's Resilience to Climate Change

NASA Astrophysics Data System (ADS)

Dougherty, W.; Edwards, B. R.; Kochtitzky, W. H.; Oddsson, B.; Gudmundsson, M. T.

2017-12-01

While more than 180 volcanoes on Earth are presently glaciated (Edwards and Kochtitzky, 2014), few studies have examined the long-term impact of a specific eruption on the affected glacier. The 2010 eruption of Eyjafjallajökull in south-central Iceland significantly damaged the small summit ice cap as well as Gígjökull, a valley glacier on the north side of the volcano. Up until the eruption in April 2010, the terminus of Gígjökull was a glacial lagoon confined by a terminal moraine. During the eruption, melting of the ice cap and valley glacier produced floods that flushed out the lagoon and infilled it with sediment. Currently, several very small lakes exist in the former lagoon, which is drained by a small stream. We documented the damage to the ice cap and Gígjökull in July 2010 on aerial overflights and the glaciers' reaction to the eruption. We again made aerial observations of the glaciers in 2011 and 2012, and have continued to monitor their changes from ground-based images. Immediately after the eruption a hole was present in the summit ice cap, containing a small lake. A complete passage from the summit ice cap to within 1 km of the glacier terminus had been melted, and was filled with volcanic debris. The damaged parts of Gígjökull included a wide opening near the head of the glacier, from which a lava flow traveled during the eruption. A canyon was melted in the ice below the vent. By summer 2011 an ice tongue was migrating into the crater from the south side of the crater rim. As of June 2017, Gígjökull had advanced to cover most of the 2010 lava flow, suggesting some glacial recovery, but no more than an isolated ice tongue, no longer fed by the main glacier, reached the lower part of the valley where the lagoon previously existed, and the glacier terminated before the 2010 eruption. Studies of Gígjökull provide insight on glaciers' influences on lava flow emplacement as well as the ability of a glacier to recover after major volcanic disturbances.

Iceland Volcano

Atmospheric Science Data Center

2013-04-23

article title:  Eyjafjallajökull, Iceland, Volcano Ash Cloud     View larger ... Europe and captured this image of the Eyjafjallajökull Volcano ash cloud as it continued to drift over the continent. Unlike other ...

Eyjafjallajökull Ash Plume Particle Properties

NASA Image and Video Library

2010-04-21

As NASA Terra satellite flew over Iceland erupting Eyjafjallajökull volcano, its Multi-angle Imaging SpectroRadiometer instrument acquired 36 near-simultaneous images of the ash plume, covering nine view angles in each of four wavelengths.

Recent unrest and magma movements at Eyjafjallajökull and Katla volcanoes, Iceland

NASA Astrophysics Data System (ADS)

Sturkell, Erik; Sigmundsson, Freysteinn; Einarsson, PáLl

2003-08-01

Katla and Eyjafjallajökull volcanoes are situated 25 km apart at the southern tip of the Eastern Volcanic Zone in Iceland. Both have been active in historic time (last 1100 years) and have a history of simultaneous activity. The much more active Katla volcano has erupted at least 20 times, and Eyjafjallajökull's two eruptions were contemporaneous with Katla eruptions. Following a quiet period of several decades, the seismicity beneath Eyjafjallajökull was high in 1994 and again in 1999. The activity culminated in July 1999 when a flash flood occurred from the Mýrdalsjökull ice cap covering Katla, associated with changes in seismicity, bursts of volcanic tremor, and the formation and deepening of ice cauldrons. We report here results of deformation observations of these events, both by GPS geodesy and tilt measurements. The 1999 increase in seismicity at Eyjafjallajökull was associated with significant inflation of the volcano. The deformation data are modeled by a point pressure source at 3.5 km depth beneath the flank of the volcano, about 4 km south of the summit crater. Maximum uplift of the model is 0.35 m. A similar model also explains deformation associated with the 1994 seismic crisis. The deformation field of the Katla volcano is more difficult to ascertain due to the extensive glacier coverage. Movements of points on nunataks on and near the caldera rim indicate inflation and magma movements at shallow level beneath the caldera in connection with the events of July 1999.

Ash from Eyjafjallajökull Volcano, Iceland Stretches over the North Atlantic

NASA Image and Video Library

2010-04-18

This image from NASA Terra spacecraft shows ash plumes from Eyjafjallajökull Volcano, Iceland stretching over the North Atlantic; the volcano erupted on April 14, 2010 bringing closure to major airports in Europe.

Synergistic Interactions of Vancomycin with Different Antibiotics against Escherichia coli: Trimethoprim and Nitrofurantoin Display Strong Synergies with Vancomycin against Wild-Type E. coli

PubMed Central

Zhou, Alice; Kang, Tina Manzhu; Yuan, Jessica; Beppler, Casey; Nguyen, Caroline; Mao, Zhiyuan; Nguyen, Minh Quan

2014-01-01

Gram-negative bacteria are normally resistant to the antibiotic vancomycin (VAN), which cannot significantly penetrate the outer membrane. We used Escherichia coli mutants that are partially sensitive to VAN to study synergies between VAN and 10 other antibiotics representing six different functional categories. We detected strong synergies with VAN and nitrofurantoin (NTR) and with VAN and trimethoprim (TMP) and moderate synergies with other drugs, such as aminoglycosides. These synergies are powerful enough to show the activity of VAN against wild-type E. coli at concentrations of VAN as low as 6.25 μg/ml. This suggests that a very small percentage of exogenous VAN does enter E. coli but normally has insignificant effects on growth inhibition or cell killing. We used the results of pairwise interactions with VAN and the other 10 antibiotics tested to place VAN into a functional category of its own, as previously defined by Yeh et al. (P. Yeh, A. I. Tschumi, and R. Kishony, Nat Genet 28:489–494, 2006, http://dx.doi.org/10.1038/ng1755). PMID:25348521

Early Holocene deglaciation of Drangajökull, Vestfirðir, Iceland

NASA Astrophysics Data System (ADS)

Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.; Zalzal, Kate

2016-12-01

The status of Icelandic ice caps during the early Holocene provides important constraints on North Atlantic climate and the mechanisms behind natural climate variability. A recent study postulates that Drangajökull on Vestfirðir, Iceland, persisted through the Holocene Thermal Maximum (HTM, 7.9-5.5 ka) and may be a relic from the last glacial period. We test this hypothesis with a suite of sediment cores from threshold lakes both proximal and distal to the ice cap's modern margin. Distal lakes document rapid early Holocene deglaciation from the coast and across the highlands south of the glacier. Sediment from Skorarvatn, a lake to the north of Drangajökull, shows that the northern margin of the ice cap reached a size comparable to its contemporary limit by ∼10.3 ka. Two southeastern lakes with catchments extending well beneath modern Drangajökull confirm that by ∼9.2 ka, the ice cap was reduced to ∼20% of its current area. A continuous 10.3ka record of biological productivity from Skorarvatn's sediment indicates local peak warmth occurred between 9 and 6.9 ka. The combination of warm and dry summers on Vestfirðir suggests that Drangajökull very likely melted completely shortly after 9.2 ka, similar to most other Icelandic ice caps.

Episodic expansion of Drangajökull, Vestfirðir, Iceland, over the last 3 ka culminating in its maximum dimension during the Little Ice Age

NASA Astrophysics Data System (ADS)

Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.; Anderson, Leif

2016-11-01

Non-linear climate change is often linked to rapid changes in ocean circulation, especially around the North Atlantic. As the Polar Front fluctuated its latitudinal position during the Holocene, Iceland's climate was influenced by both the warm Atlantic currents and cool, sea ice-bearing Arctic currents. Drangajökull is Iceland's fifth largest ice cap. Climate proxies in lake sediment cores, dead vegetation emerging from beneath the ice cap, and moraine segments identified in a new DEM constrain the episodic expansion of the ice cap over the past 3 ka. Collectively, our data show that Drangajökull was advancing at ∼320 BCE, 180 CE, 560 CE, 950 CE and 1400 CE and in a state of recession at ∼450 CE, 1250 CE and after 1850 CE. The Late Holocene maximum extent of Drangajökull occurred during the Little Ice Age (LIA), occupying 262 km2, almost twice its area in 2011 CE and ∼20% larger than recent estimates of its LIA dimensions. Biological proxies from the sediment fill in a high- and low-elevation lake suggest limited vegetation and soil cover at high elevations proximal to the ice cap, whereas thick soil cover persisted until ∼750 CE at lower elevations near the coast. As Drangajökull expanded into the catchment of the high-elevation lake beginning at ∼950 CE, aquatic productivity diminished, following a trend of regional cooling supported by proxy records elsewhere in Iceland. Correlations between episodes of Drangajökull's advance and the documented occurrence of drift ice on the North Icelandic Shelf suggest export and local production of sea ice influenced the evolution of NW Iceland's Late Holocene climate.

Traffic safety facts 1996 : occupant protection

DOT National Transportation Integrated Search

1997-01-01

In 1996, 32,317 occupants of passenger vehicles (cars, light trucks, vans, and utility vehicles) were killed in motor vehicle traffic crashes, 77 percent of the 41,907 traffic fatalities reported for the year. Among passenger vehicle occupants over 4...

Traffic safety facts 1994 : occupant protection

DOT National Transportation Integrated Search

1995-01-01

In 1994, 30,780 occupants of passenger vehicles (cars, light trucks, vans, and utility vehicles) were killed in motor vehicle traffic crashes, 76 percent of the 40,676 traffic fatalities reported for the year. Among passenger vehicle occupants over 4...

Traffic safety facts 1995 : occupant protection

DOT National Transportation Integrated Search

1996-01-01

In 1995, 31,897 occupants of passenger vehicles (cars, light trucks, vans, and utility vehicles) were killed in motor vehicle traffic crashes, 76 percent of the 41,798 traffic fatalities reported for the year. Among passenger vehicle occupants over 4...

Traffic safety facts 1993 : occupant protection

DOT National Transportation Integrated Search

1994-01-01

In 1993, 26,873 front-seat occupants of passenger vehicles (cars, light trucks, vans, and utility vehicles) were killed in motor vehicle traffic crashes, 67 percent of the 40,115 traffic fatalities reported for the year. Among front-seat passenger ve...

Eruption of Eyjafjallajökull Volcano, Iceland

NASA Image and Video Library

2017-12-08

March 31, 2010..The volcanic eruption near Eyjafjallajökull persists into its second week, with continued lava fountaining and lava flows spilling into nearby canyons. The eruption is located at the Fimmvörduháls Pass between the Eyjafjallajökull ice field to the west (left) and the Mýrdalsjökull ice field to the east (right). This natural-color satellite image was acquired on March 26, 2010, by the MODIS aboard NASA’s Terra satellite. Dark ash and scoria cover the northern half of the Fimmvörduháls Pass. White snow covers the rest of the pass, sandwiched between white glaciers. Snow-free land is tan, brown, or dark gray, devoid of vegetation in early spring. To download a high res version of this image go to: modis.gsfc.nasa.gov/gallery/individual.php?db_date=2010-0... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Holocene surge-history of the Eyjabakkajökull glacier inferred from varved lake sediments on eastern Iceland

NASA Astrophysics Data System (ADS)

Striberger, J.; Bjorck, S.; Ingolfsson, O.; Kjaer, K.; Snowball, I.; Uvo, C. B.

2009-12-01

Properties of varved lake sediments from Lake Lögurinn on eastern Iceland and their link to glacial processes of Eyjabakkajökull, a surging outlet glacier of the Vatnajökull ice cap, is examined. An 18 m long sediment sequence obtained from the lake, covering at least the past ~ 9 200 years, displays a distinct recurring pattern of light-coloured clay dominated laminae sections. The thickness of the light-coloured laminae is mainly controlled by the amount of glacial rock flour transported from Eyjabakkajökull. These light laminae are interlaid by coarser dark-coloured laminae mainly formed by suspended matter transported to the lake by the large non-glacial river Grímsá. During the recent surge of Eyjabakkajökull in 1972, the amount of suspended matter transported to the lake increased significantly. The surge was followed by years of recurring drainages of Lake Háöldulón, an ice-dammed lake that was formed shortly after the surge. As a result, the amount of glacial rock flour transported to Lake Lögurinn was higher than usual as long as Lake Háöldulón continued to drain (i.e. as long as the ice front was in an advanced position enough to dam the lake). This increase in glacially derived rock flour is reflected in the sediments, as the varve that was formed in 1972 constitutes the thickest light-coloured laminae deposited during the 20th century, which is followed by the second thickest light-coloured laminae, deposited in 1973. From there on, the thicknesses of the light-coloured laminae gradually fade out. Based on these modern observations, we suggest that the recurring cyclic pattern of light-coloured clay dominated laminae sections in the sediment sequence is related to past surges of Eyjabakkajökull, followed by drainages of Lake Háöldulón. Recurring cycles of light-coloured clay dominated laminae began to develop close to the Hekla-3 and Hekla-4 tephras (ca. 3000-4000 years BP), which also coincides with the time when the varves became more distinct. Further down in the sequence, the recurring cycles of light-coloured laminae are not found and any varves are in general diffuse or missing. Hypothetically, the reason for this might be that the suspended matter delivered from the glacier was transported elsewhere at this time. However, based on the large-scale morphology of the area, we find it more likely that Eyjabakkajökull, and thus parts of, or the whole Vatnajökull ice cap, was smaller or perhaps not present during the mid-Holocene and thus had little or no influence on the sedimentation in Lake Lögurinn.

Effectiveness and efficiency of safety belt and child restraint usage programs

DOT National Transportation Integrated Search

1982-03-01

Problem: Each year, approximately 34,000 persons are killed and 520,000 receive moderate to severe injuries as occupants of passenger cars, light trucks and vans. Approximately half ofthese deaths and injuries could be avoided if all such occupants w...

Residents' attitudes and behaviour before and after the 2010 Eyjafjallajökull eruptions—a case study from southern Iceland

NASA Astrophysics Data System (ADS)

Bird, Deanne K.; Gísladóttir, Guðrún

2012-08-01

While the disruption to international air travel caused by the eruption of Iceland's Eyjafjallajökull volcano in 2010 has been well documented, the significant social impacts on local residents from ash fall to the south and east of the crater are less well-known. These impacts and attitudes of impacted residents and emergency managers are the foci of our present study. Prior to and during the eruption, officials worked to protect the local population from the glacial outburst floods (jökulhlaup) that were of primary concern. The success of these endeavours can in part be attributed to a regional evacuation exercise held in March 2006, an exercise that was carried out with respect to a possible eruption at another volcano, Katla, that is located 25 km to the east of Eyjafjallajökull. Eruptions at either volcano will impact the same communities. Our study here concentrates on Álftaver, a small farming community, located approximately 60 km east-southeast of Eyjafjallajökull and 30 km southeast of Katla. Álftaver has been the subject of longitudinal studies carried out in 2004, 2006, and 2008; these studies highlighted the difficulties that emergency managers face in developing appropriate response strategies acceptable to vulnerable communities. The 2010 Eyjafjallajökull eruptions presented an opportunity to re-assess residents' attitudes and behaviour in relation to volcanic risk management in the wake of their first-hand experiences with volcanic hazards. To achieve this, interviews were conducted with residents and emergency management officials and a questionnaire was distributed to residents. This paper presents the results of this survey and examines changes in attitudes towards volcanic risk management. It was apparent that the experience of ash fall from Eyjafjallajökull provided a better perspective of what could be expected from a Katla eruption and that attitudes towards emergency management had evolved accordingly. Importantly, officials' perceptions of risk are now more aligned with those of residents and both recognise the need for more detailed and concise information regarding the impacts of ash fall during and following volcanic eruptions.

Data on the surface morphology of additively manufactured Ti-6Al-4V implants during processing by plasma electrolytic oxidation.

PubMed

van Hengel, Ingmar A J; Riool, Martijn; Fratila-Apachitei, Lidy E; Witte-Bouma, Janneke; Farrell, Eric; Zadpoor, Amir A; Zaat, Sebastian A J; Apachitei, Iulian

2017-08-01

Additively manufactured Ti-6Al-4V implants were biofunctionalized using plasma electrolytic oxidation. At various time points during this process scanning electron microscopy imaging was performed to analyze the surface morphology (van Hengel et al., 2017) [1]. This data shows the changes in surface morphology during plasma electrolytic oxidation. Data presented in this article are related to the research article "Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus" (van Hengel et al., 2017) [1].

An analysis of options available for developing a common laser ray tracing package for Ares and Kull code frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weeratunga, S K

Ares and Kull are mature code frameworks that support ALE hydrodynamics for a variety of HEDP applications at LLNL, using two widely different meshing approaches. While Ares is based on a 2-D/3-D block-structured mesh data base, Kull is designed to support unstructured, arbitrary polygonal/polyhedral meshes. In addition, both frameworks are capable of running applications on large, distributed-memory parallel machines. Currently, both these frameworks separately support assorted collections of physics packages related to HEDP, including one for the energy deposition by laser/ion-beam ray tracing. This study analyzes the options available for developing a common laser/ion-beam ray tracing package that can bemore » easily shared between these two code frameworks and concludes with a set of recommendations for its development.« less

The evaluation of damage mechanism of unreinforced masonry buildings after Van (2011) and Elazig (2010) Earthquakes

NASA Astrophysics Data System (ADS)

Güney, D.; Aydin, E.; Öztürk, B.

2015-07-01

On March 8th, 2010 Karakocan-Elazig earthquake of magnitude 6.0 occurred at a region where masonry and adobe construction is very common. Karakocan-Elazig is located in a high seismicity region on Eastern Anatolian Fault System (EAFS). Due to the earthquake, 42 people were killed and 14’113 buildings were damaged. Another city, Van located at South east of Turkey is hit by earthquakes with M = 7.2 occurred on October 23rd, 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanli village) and M = 5.6 on November 9th, 2011 with an epicenter near the town of Edremit, south of Van and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 10’000 buildings were seriously damaged. There are many traditional types of structures existing in the region hit by earthquakes (both Van and Elazig). These buildings were built as adobe, unreinforced masonry or mixed type. These types of buildings are very common in rural areas (especially south and east) of Turkey because of easy workmanship and cheap construction cost. Many of those traditional type structures experienced serious damages. The use of masonry is very common in some of the world's most hazard-prone regions, such as in Latin America, Africa, the Indian subcontinent and other parts of Asia, the Middle East, and southern Europe. Based on damage and failure mechanism of those buildings, the parameters affecting the seismic performance of those traditional buildings are analyzed in this paper. The foundation type, soil conditions, production method of the masonry blocks, construction method, the geometry of the masonry walls, workmanship quality, existence of wooden beams, type of roof, mortar between adobe blocks are studied in order to understand the reason of damage for these types of buildings.

Comparative activity of tedizolid and glycopeptide combination therapies for the treatment of Staphylococcus aureus infections: an in vitro and in vivo evaluation against strains with reduced susceptibility to glycopeptides.

PubMed

Betts, J W; Abdul Momin, H F; Phee, L M; Wareham, D W

2018-02-01

Glycopeptides are widely used for the treatment of meticillin-resistant Staphylococcus aureus (MRSA) infections. Although difficult to detect, isolates with reduced (GISA), hetero (hGISA) or complete (GRSA) resistance to glycopeptides are increasingly reported. Optimal therapy for such strains is unknown. We compared the in vitro and in vivo activity of tedizolid (TED), a recently licensed oxazolidonone, with vancomycin (VAN) and teicoplanin (TEIC) combined with fusidic acid (FD) or rifampicin (RIF) against S. aureus (SA) with reduced susceptibility to glycopeptides. Susceptibility was determined for six (GISA, hGISA and GRSA) reference strains and 72 clinical MRSA isolates screened for hGISA/GISA-like phenotypes. Synergy and bactericidal activity were assessed using chequerboard and time-kill assays. The G. mellonella wax moth caterpillar model was used to measure the activity of TED and the combinations in vivo. Glycopeptide MICs (VAN/TEIC) ranged from 0.5-8/4 and 0.125-1 for TED. No significant synergy was noted when VAN/TEIC were combined with either RIF or FD. Time-kill assays confirmed that TED was bacteriostatic but superior to VAN and TEIC against GISA strains. In G. mellonella TED was more effective than TEIC monotherapy versus GISA strains. The combination of TEIC with RIF was the most effective combination overall, both in vitro and in vivo. TED had good in vitro activity versus MRSA including those with reduced susceptibility to glycopeptides. Although bacteriostatic, it was effective in the G. mellonella model and superior to TEIC in the treatment of GISA. Although this supports the use of TED for MRSA and GISA, the TEIC/RIF combination also warrants further study.

The impacts of the Öræfajökull eruption in AD 1362 and climate change on cultural landscape dynamics in the province of Öræfi south of Vatnajökull glacier, Iceland

NASA Astrophysics Data System (ADS)

Sigurmundsson, F.; Gísladóttir, G.; Erlendsson, E.

2013-12-01

Environmental changes can be attributed to both natural processes and human influences. The aim of this study is to examine the effects of volcanism and climate change on the development of land quality and cultural landscapes in the province of Öræfi in the Austur-Skaftafellssýsla district, south of Vatnajökull glacier, over the last 1100 years. Few areas in Iceland are as vulnerable to climate changes and volcanic eruptions as the region south of Vatnajökull glacier. The region has been repeatedly affected by tephra fallout from explosive eruptions, most notably the Öræfajökull eruption in AD 1362. This research employs historical written sources to investigate changes in the cultural and natural landscape. Historical and palaeoenvironmental data will be accumulated and stored in a database designed for the research, allowing data to be analyzed and presented on maps. Preliminary results show that from the onset of the settlement in the late 9th century until AD 1362 Öræfi was a wealthy, densely populated farming society, with many large farm estates and large number of livestock (cattle and sheep) sustained by the natural vegetation. The farm estates were 40 by the mid 14th century and the churches were four. The first records of land ownership show that the Church had accumulated the most valuable holdings in Öræfi shortly before the Öræfajökull volcanic eruption in AD 1362. Out of the 40 farm estates 12 belonged to the Church and on a national scale the churches in Öræfi were richer in livestock, sacramentals and missals compared to churches in other parts of Iceland. The Öræfajökull volcanic eruption in AD 1362 had devastating long term impact on the settlement and terrestrial ecosystem in Öræfi. The area was abandoned following the eruption and in the early 15th century only eight out of the 40 farm estates prior to the eruption were settled. The values of the estates shrunk dramatically as did the arable land. The number of churches diminished by 3 and despite economic loss, still 2 farm estates belonged to the Church. Thus, the ownership pattern did not change but the area eligible for farming was severely reduced. The land quality and cultural landscapes in Öræfi province further suffered from changing river systems, outburst floods and advancing glaciers during the Little Ice Age.

Comparison of Six Generic Vancomycin Products for Treatment of Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis in Rabbits

PubMed Central

Tattevin, P.; Saleh-Mghir, A.; Davido, B.; Ghout, I.; Massias, L.; Garcia de la Maria, C.; Miró, J. M.; Perronne, C.; Laurent, F.

2013-01-01

Concerns have recently emerged about the potency and the quality of generic vancomycin (VAN) products approved for use in humans, based on experiments in a neutropenic mouse thigh infection model. However, other animal models may be more appropriate to decipher the bactericidal activities of VAN generics in vivo and to predict their efficacy in humans. We aimed to compare the bactericidal activities of six generic VAN products currently used in France (Mylan and Sandoz), Spain (Hospira), Switzerland (Teva), and the United States (Akorn-Strides and American Pharmaceutical Products [APP]) in a rabbit model of aortic valve endocarditis induced by 8 × 107 CFU of methicillin-resistant Staphylococcus aureus (MRSA) strain COL (VAN MIC, 1.5 μg/ml). In vitro, there were no significant differences in the time-kill curve studies performed with the six generic VAN products. Ten rabbits in each group were treated with intravenous (i.v.) VAN, 60 mg/kg of body weight twice a day (b.i.d.) for 4 days. Mean peak serum VAN levels, measured 45 min after the last injection, ranged from 35.5 (APP) to 45.9 μg/ml (Teva). Mean trough serum VAN levels, measured 12 h after the last injection, ranged from 2.3 (Hospira) to 9.2 (APP) μg/ml. All generic VAN products were superior to controls (no treatment) in terms of residual organisms in vegetations (P < 0.02 for each comparison) and in the spleen (P < 0.005 for each comparison). Pairwise comparisons of generic VAN products found no significant differences. In conclusion, a stringent MRSA endocarditis model found no significant differences in the bactericidal activities of six generic VAN products currently used in Europe and America. PMID:23254435

A preliminary geomorphological map from the Múlajökull drumlin field, Iceland

NASA Astrophysics Data System (ADS)

Jonsson, S. A.; Schomacker, A.; Benediktsson; Johnson, M.; Ingolfsson, O.

2012-12-01

The drumlin field in front of Múlajökull, a surge-type, outlet glacier from Hofsjökull in Iceland, is the only known active drumlin field (Johnson et al., 2010). The aim of this study is to further explore the distribution and formation of drumlins and drumlin fields in a modern glacial environment. We use data from Digital Elevation Models (DEMs), aerial imagery and field mapping. Here we present a preliminary geomorphological map based on remote sensing and fieldwork in 2010 and 2011. Geomorphological mapping of the drumlin field both with DEMs and ground proofing has revealed over 100 drumlins and a number of drumlinized ridges. The drumlins furthest from the present ice margin are broader and have lower relief than those closer to the ice. We suggest that this reflects an evolution of the drumlin form during recurrent surging. The drumlins farther away from the ice have experienced fewer surges than those that have just been uncovered due to present retreat of the ice margin. During successive surges, the drumlins become narrower and develop a higher relief. Reference: Johnson, M.D., Schomacker, A., Benediktsson, Í. Ö., Geiger, A. J., Ferguson, A. and Ingólfsson, Ó. 2010, Active drumlin field revealed at the margin of Múlajökull, Iceland: A surge-type glacier: Geology v. 38, p. 943-946.

Five 'Supercool' Icelandic Glaciers

NASA Astrophysics Data System (ADS)

Knudsen, O.; Roberts, M. J.; Roberts, M. J.; Tweed, F. S.; Russell, A. J.; Lawson, D. E.; Larson, G. J.; Evenson, E. B.; Bjornsson, H.

2001-12-01

Sediment entrainment by glaciohydraulic supercooling has recently been demonstrated as an effective process at Matanuska glacier, Alaska. Although subfreezing meltwater temperatures have been recorded at several Alaskan glaciers, the link between supercooling and sediment accretion remains confined to Matanuska. This study presents evidence of glaciohydraulic supercooling and associated basal ice formation from five Icelandic glaciers: Skeidarárjökull, Skaftafellsjökull, Kvíárjökull, Flaájökull, and Hoffellsjökull. These observations provide the best example to-date of glaciohydraulic supercooling and related sediment accretion outside Alaska. Fieldwork undertaken in March, July and August 2001 confirmed that giant terraces of frazil ice, diagnostic of the presence of supercooled water, are forming around subglacial artesian vents. Frazil flocs retrieved from these vents contained localised sandy nodules at ice crystal boundaries. During periods of high discharge, sediment-laden frazil flocs adhere to the inner walls of vents, and continue to trap suspended sediment. Bands of debris-rich frazil ice, representing former vents, are texturally similar to basal ice exposures at the glacier margins, implying a process-form relationship between glaciohydraulic freeze-on and basal ice formation. It is hypothesised that glaciohydraulic supercooling is generating thick sequences of basal ice. Observations also confirm that in situ melting of basal ice creates thick sedimentary sequences, as sediment structures present in the basal ice can be clearly traced into ice-marginal ridges. Glaciohydraulic supercooling is an effective sediment entrainment mechanism at Icelandic glaciers. Supercooling has the capacity to generate thick sequences of basal ice and the sediments present in basal ice can be preserved. These findings are incompatible with established theories of intraglacial sediment entrainment and basal ice formation; instead, they concur with, and extend, the current model of Matanuska-type glaciohydraulic supercooling. This work adds a new dimension to the understanding of debris entrainment in temperate glaciers.

Element variations in rhyolitic magma resulting from gas transport

NASA Astrophysics Data System (ADS)

Berlo, K.; Tuffen, H.; Smith, V. C.; Castro, J. M.; Pyle, D. M.; Mather, T. A.; Geraki, K.

2013-11-01

Tuffisite veins are glass-filled fractures formed when magma fragments during degassing within the conduit. These veins form transient channels through which exsolved gases can escape from magma. The purpose of this study is to determine the extent to which chemical heterogeneity within the melt results from gas transport, and assess how this can be used to study magma degassing. Two tuffisite veins from contrasting rhyolitic eruptions at Torfajökull (Iceland) and Chaitén (Chile) were studied in detail. The tuffisite vein from Torfajökull is from a shallow dissected conduit (∼70 ka) that fed a degassed lava flow, while the sample from Chaitén was a bomb ejected during the waning phases of Plinian activity in May 2008. The results of detailed in situ chemical analyses (synchrotron XRF, FTIR, LA-ICP-MS) show that in both veins larger vesiculated fragments are enriched in volatile elements (Torfajökull: H, Li, Cl; Chaitén: Li, Cl, Cu, Zn, As, Sn, Sb) compared to the host, while the surrounding smaller particles are depleted in the Torfajökull vein (Li, Cl, Zn, Br, Rb, Pb), but enriched in the Chaitén vein (K, Cu, Zn, As, Mo, Sb, Pb). The lifespans of both veins and the fluxes of gas and particles through them can be estimated using diffusion profiles and enrichment factors. The Torfajökull vein had a longer lifespan (∼a day) and low particle velocities (∼cm/s), while the Chaitén vein was shorter lived (<1 h) with a high gas velocity (∼m/s). These differences are consistent with the contrasting eruption mechanisms (effusive vs. explosive). The amount of magma that degassed through the Chaitén vein is more than ten times the volume of the vein itself, requiring the vein to tap into pre-exsolved gas pockets. This study highlights that tuffisite veins are highly efficient gas pathways and thereby impart chemical diversity in volatile elements on the melt.

Analyzing Relationships between Geochemical Composition, Spectral Reflectance, Broad-band Albedo and Thickness of Supra-glacial Tephra Deposits from the Eruptions of Eyafjallajökull and Grímsvötn Volcanoes in 2010 and 2011.

NASA Astrophysics Data System (ADS)

Möller, R.; Möller, M.; Kukla, P. A.; Schneider, C.; Römer, W.; Lehmkuhl, F.; Gudmundsson, M. T.

2016-12-01

On Iceland, explosive subglacial eruptions are common. The two latest eruptions were at Eyjafjallajökull 2010 and at Grímsvötn 2011. Both eruptions produced considerable amounts of tephra fallout that were deposited over large parts of major Icelandic ice caps. These extensive supraglacial tephra deposits are known to considerably alter the energy and mass balance of the ice caps at a strong spatial and temporal variability. We present a statistical evaluation of relationships and links between geochemistry, thermal conductivity, spectral reflectance characteristics, albedo and deposition thickness of the tephra covers and their variability in space and time. Samples of the tephra deposits were gathered in the field and analyzed in the laboratory regarding their chemical and mineralogical composition using X-ray fluorescence and diffraction analyses. Spatial patterns of spectral reflectance over the tephra-covered areas of the three major ice caps Eyjafjallajökull, Myrdalsjökull and Vatnajökull were obtained from multispectral ASTER and MODIS satellite datasets. Spatial patterns of broad-band albedo across the tephra-covered areas and differences to the albedo of unaffected surfaces were obtained from remotely-sensed data and geostatistical modeling. Changes in tephra-cover thickness with time were assessed using a modeling approach that includes thermal conductivity of the tephra cover and surface temperature. The former is derived from laboratory analysis while the latter is based on MODIS observations. We found that there are characteristic patterns of spectral reflectance that could be linked to deposition thickness and geochemical composition of the respective tephra. The temporal variability of the albedo patterns across the ice caps is strongly linked to the evolution of the deposition thicknesses over time.

47 CFR 90.303 - Availability of frequencies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... table lists frequency bands that are available for assignment in specific urban areas. The available... available for use by eligibles in the Public Safety Radio Pool in the following areas: New York City; Nassau...)” curve in Figure B in 47 CFR 90.309(b). (ii) For base stations located west of the Hudson River, Kill Van...

Tests with DDT foliar sprays to control the California flatheaded borer

Treesearch

Robert L. Lyon

1959-01-01

The California flatheaded borer (Melanophila californica Van Dyke) kills an estimated 30 million board-feet of pine timber in California each year. The insect is especially troublesome on ponderosa and Jeffrey pines growing on dry sites, and it has caused serious losses in Jeffrey pine stands on valuable , watershed and recreational lands of...

Targeting intracellular Staphylococcus aureus to lower recurrence of orthopaedic infection.

PubMed

Dusane, Devendra H; Kyrouac, Douglas; Petersen, Iris; Bushrow, Luke; Calhoun, Jason H; Granger, Jeffrey F; Phieffer, Laura S; Stoodley, Paul

2018-04-01

Staphylococcus aureus is often found in orthopaedic infections and may be protected from commonly prescribed antibiotics by forming biofilms or growing intracellularly within osteoblasts. To investigate the effect of non-antibiotic compounds in conjunction with antibiotics to clear intracellular and biofilm forming S. aureus causing osteomyelitis. SAOS-2 osteoblast-like cell lines were infected with S. aureus BB1279. Antibiotics (vancomycin, VAN; and dicloxacillin, DICLOX), bacterial efflux pump inhibitors (piperine, PIP; carbonyl cyanide m-chlorophenyl hydrazone, CCCP), and bone morphogenetic protein (BMP-2) were evaluated individually and in combination to kill intracellular bacteria. We present direct evidence that after gentamicin killed extracellular planktonic bacteria and antibiotics had been stopped, seeding from the infected osteoblasts grew as biofilms. VAN was ineffective in treating the intracellular bacteria even at 10× MIC; however in presence of PIP or CCCP the intracellular S. aureus was significantly reduced. Bacterial efflux pump inhibitors (PIP and CCCP) were effective in enhancing permeability of antibiotics within the osteoblasts and facilitated killing of intracellular S. aureus. Confocal laser scanning microscopy (CLSM) showed increased uptake of propidium iodide within osteoblasts in presence of PIP and CCCP. BMP-2 had no effect on growth of S. aureus either alone or in combination with antibiotics. Combined application of antibiotics and natural agents could help in the treatment of osteoblast infected intracellular bacteria and biofilms associated with osteomyelitis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1086-1092, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash

PubMed Central

Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

2013-01-01

Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s−1 in each storm with gusts up to 38.7 m s−1. Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m−1 during the most intense storm event with a rate of 1,440 kg m−1 hr−1 for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions. PMID:23409248

An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash.

PubMed

Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

2013-01-01

Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s(-1) in each storm with gusts up to 38.7 m s(-1). Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m(-1) during the most intense storm event with a rate of 1,440 kg m(-1) hr(-1) for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions.

Curved manifolds with conserved Runge-Lenz vectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngome, J.-P.

2009-12-15

van Holten's algorithm is used to construct Runge-Lenz-type conserved quantities, induced by Killing tensors, on curved manifolds. For the generalized Taub-Newman-Unti-Tamburino metric, the most general external potential such that the combined system admits a conserved Runge-Lenz-type vector is found. In the multicenter case, the subclass of two-center metric exhibits a conserved Runge-Lenz-type scalar.

Curved manifolds with conserved Runge-Lenz vectors

NASA Astrophysics Data System (ADS)

Ngome, J.-P.

2009-12-01

van Holten's algorithm is used to construct Runge-Lenz-type conserved quantities, induced by Killing tensors, on curved manifolds. For the generalized Taub-Newman-Unti-Tamburino metric, the most general external potential such that the combined system admits a conserved Runge-Lenz-type vector is found. In the multicenter case, the subclass of two-center metric exhibits a conserved Runge-Lenz-type scalar.

What makes a primary tephra fall?

NASA Astrophysics Data System (ADS)

Hoskuldsson, A.; Gudmundsson, M.; Thordarsson, T.; Öladottir, B.; Sigmarsson, O.; Larsen, G.

2012-04-01

Two recent explosive eruptions in Iceland have raised the thought about what makes a primary tephra fall and how will that be presented in the geological record? Eyjafjallajökull erupted in 2010, an eruption lasting for about 2 months. Fall of tephra fell more or less around the volcano during that time. Grimsvötn erupted in 2011, an powerful eruption lasting for about 7 days, with a main tephra producing phase during the first 3 days. Not only where the two eruptions different in intensity, Eyjafjallajökull being much lower producing about half the volume of Grimsvötn in about 2 months time and a plume not reaching higher than about 10-12 km, Grimsvotn on the other hand needed only 3 days to double the production of Eyjafjallajökull, and sending the ash plume up to about 20 km in the atmosphere. During Eyjafjallajökull atmospheric winds where gentle, leading to tephra precipitation under ideal conditions, tephra blanketed the surrounding land and mountain slopes. During the spring 2011 on the other hand lower atmospheric winds where strong from north, while stratospheric winds where westerly carrying ash in two directions. During the Grímsvötn explosive phase, winds where strong, leading to a peculiar deposition of the tephra. While the Eyjafjallajökull tephra shows typical characteristics of volcanic material falling from the sky in gentle weather, like dogs-paw snow, leading to wide area equal layering, the Grimsvötn tephra came to a rest under high wind showing primary cross bedding, primary erosion surfaces and a complied depletion of fines. Further differences observed are that despite the difference in preservation potential of the tephra from the two eruptions, both have high preservation potential in the near vent field while the smaller eruption has higher preservation potential in the far field of the volcano, due to more favourable weather conditions. In this talk we shall also address the preservation potential of explosive eruption in the geological record and address possible indicators for a major explosive eruption when in a volcanic area.

The Morsárjökull rock avalanche in the southern part of the Vatnajökull glacier, south Iceland

NASA Astrophysics Data System (ADS)

Sæmundsson, Şorsteinn; Sigurősson, Ingvar A.; Pétursson, Halldór G.; Decaulne, Armelle; Jónsson, Helgi P.

2010-05-01

On the 20th of March 2007 a large rock avalanche fell on Morsárjökull, one of the outlet glaciers from the southern part of the Vatnajökull ice cap, in south Iceland. This is considered to be one of the largest rock avalanches which have occurred in Iceland during the last decades. It is believed that it fell in two separate stages, the main part fell on the 20th of March and the second and smaller one, on the 17th of April 2007. The Morsárjökull outlet glacier is about 4 km long and surrounded by up to 1000 m high valley slopes. The outlet glacier is fed by two ice falls which are partly disconnected to the main ice cap of Vatnajökull, which indicates that the glacier is mainly fed by ice avalanches. The rock avalanche fell on the eastern side of the uppermost part of the Morsárjökull outlet glacier and covered about 1/5 of the glacier surface, an area of about 720,000 m2. The scar of the rock avalanche is located on the north face of the headwall above the uppermost part of the glacier. It is around 330 m high, reaching from about 620 m up to 950 m, showing that the main part of the slope collapsed. It is estimated that about 4 million m3 of rock debris fell on the glacier, or about 10 million tons. The accumulation lobe is up to 1.6 km long, reaching from 520 m a.s.l., to about 350 m a.s.l. Its width is from 125 m to 650 m, or on average 480 m. The total area which the lobe covers is around 720.000 m2 and its mean thickness 5.5 m. The surface of the lobe shows longitudinal ridges and grooves and narrow flow-like lobes, indicating that the debris mass evolved down glacier as a mixture of a slide and debris flow. The debris mass is coarse grained and boulder rich. Blocks over 5 to 8 m in diameter are common on the edges of the lobe up to 1.6 km from the source. No indication was observed of any deformation of the glacier surface under the debris mass. The first glaciological measurements of Morsárjökull outlet glacier were carried out in the year 1896 and it is evident that since that time the glacier has retreated considerably and during the last decade the melting has been very rapid. It is thought that undercutting of the mountain slope by glacial erosion and the retreat of the glacier are the main contributing factors leading to the rock avalanche. The glacial erosion has destabilized the slope, which is mainly composed of palagonite and dolerite rocks, affected by geothermal alteration. Hence a subsequent fracture formation has weakened the strength of the bedrock. However the exact triggering factor is not known. No seismic activity or meteorological signal such as heavy rainfall or intensive snowmelt recorded prior to the rock avalanche which could be interpreted as triggering factors. From 2007 considerable changes have been observed on the glacier. The ice-front has retreated considerably and the debris lobe of the rock avalanche has moved downward along with the glacier ice about 90-100 m per year. The rocky material, by insulating the ice, has reduced its melting, leading to a relative "thickening" of the ice beneath the rock avalanche debris up to 11-15 m per year. After three melting seasons the debris mass was about 29 m above the surrounding ice surface.

GPR-derived architecture of jökulhlaup sediments, Gígjökull, Iceland

NASA Astrophysics Data System (ADS)

Harrison, Devin; Ross, Neil; Russell, Andrew; Dunning, Stuart

2017-04-01

A warming global climate has implications for glacial retreat and meltwater generation. In Iceland, the potential frequency and magnitude of jökulhlaup (glacial outburst flood) hazards from ice-dammed and moraine-dammed lakes may be increased by: (i) increased glacial meltwater production; and (ii) the glacio-isostatic response of the mantle driven by deglaciation, which is hypothesised to increase volcanic activity. The high peak-discharges of volcanically-induced jökulhlaups in Iceland have the ability to deposit significant volumes of sediment, causing major geomorphic change and societal impacts. Understanding geomorphological process associated with jökulhlaups can assist in predicting and evaluating future jökulhlaup behaviour and impacts. The 2010 Eyjafjallajökull eruption produced multiple jökulhlaups resulting in major sediment deposition and proglacial aggradation. Observations of the timing, scale and hydraulic properties of these jökulhlaups during the eruption have provided a unique opportunity to investigate the impact of ice-rich meltwater flows on the proglacial environment. Using low-frequency (40 MHz) ground penetrating radar (GPR) and differential GPS (dGPS) surveys of the Gígjökull basin, this study has: (1) geophysically characterised the thick sequence of sedimentary deposits associated with the Eyjafjallajökull eruption, to test conceptual models of jökulhlaup deposition; and (2) quantified post-depositional (2010-2016) elevation change, to evaluate the role of buried ice on post-jökulhlaup landscape response and recovery. The jökulhlaup deposits are characterised by three prominent sediment sub-units, delimited by strong continuous reflectors, and displaying discontinuous undulating reflections (indicating the presence of dunes or anti-dunes). The structures within these sub-units provide insight into the fluvial processes associated with multiple high-magnitude flood events and their relation to the hydraulic properties and rheology. Our geodetic observations demonstrate significant lowering of the surface of the jökulhlaup sediments over six years since deposition (i.e. 0.456 ma-1 between 2010 and 2015; increasing to 1.926 ma-1 between 2015 and 2016), which we interpret to be the result of the meltout of buried ice within these sediments. Our findings will quantify the hazard potential of ice-rich jökulhlaup flows, by constraining sub-surface properties and their spatial relation to the highest rates of elevation change. The association of geomorphological processes of the Eyjafjallajökull jökulhlaups in relation to hydrograph shape will provide useful information for future mitigation and constraints for jökulhlaup propagation modelling. The integration of hydraulic observation and sedimentary products of the Eyjafjallajökull jökulhlaups can also provide process-insight into Quaternary megafloods (e.g. outburst floods from the Laurentide ice-sheet) and megafloods on other planets (e.g. Mars).

Tropospheric impacts of volcanic halogen emissions: first simulations of reactive halogen chemistry in the Eyjafjallajökull eruption plume

NASA Astrophysics Data System (ADS)

Roberts, Tjarda

2013-04-01

Volcanic plumes are regions of high chemical reactivity. Instrumented research aircraft that probed the 2010 Icelandic Eyjafjallajökull eruption plume identified in-plume ozone depletion and reactive halogens (Cl, BrO), the latter also detected by satellite. These measurements add to growing evidence that volcanic plumes support rapid reactive halogen chemistry, with predicted impacts including depletion of atmospheric oxidants and mercury deposition. However, attempts to simulate volcanic plume halogen chemistry and predict impacts are subject to considerable uncertainties. e.g. in rate constants for HOBr reactive uptake (see this session: EGU2013-6076), or in the high-temperature initialisation. Model studies attempting to replicate volcanic plume halogen chemistry are restricted by a paucity of field data that is required both for model tuning and verification, hence reported model 'solutions' are not necessarily unique. To this end, the aircraft, ground-based and satellite studies of the Eyjafjallajökull eruption provide a valuable combination of datasets for improving our understanding of plume chemistry and impacts. Here, PlumeChem simulations of Eyjafjallajökull plume reactive halogen chemistry and impacts are presented and verified by observations for the first time. Observed ozone loss, a function of plume strength and age, is quantitatively reproduced by the model. Magnitudinal agreement to reported downwind BrO and Cl is also shown. The model predicts multi-day impacts, with reactive bromine mainly as BrO, HOBr and BrONO2 during daytime, and Br2 and BrCl at night. BrO/SO2 is reduced in more dispersed plumes due to enhanced partitioning to HOBr, of potential interest to satellite studies of BrO downwind of volcanoes. Additional predicted impacts of Eyjafjallajökull volcanic plume halogen chemistry include BrO-mediated depletion of HOx that reduces the rate of SO2 oxidation to H2SO4, hence the formation of sulphate aerosol. The model predicts NOx is rapidly converted into nitric acid (via BrONO2). Such HNO3-formation might contribute towards new particle formation, noting reported very high in-plume particle nucleation rates in Eyjafjallajökull plume. Thus, plume halogen chemistry influences on aerosol formation and growth are emphasized regarding studies of climatic and health impacts of volcanic aerosol. As the plume disperses, in-plume ozone concentrations partially recover due to entrainment of O3-rich background air. However, the cumulative net impact on ozone depletion continues. Whilst the global tropospheric impact of Eyjafjallajokull is small, up-scaling of the model findings in the context of present day global volcanic degassing and recent historic eruptions indicates potential for significant impacts of global volcanic halogen emissions on tropospheric ozone, particularly during periods of enhanced volcanic activity. Notably, this model-observation study of Eyjafjallajökull plume exhibits contrasts to a related model-observation study that quantified ozone loss in Redoubt volcano eruption plume (Kelly et al., JVGR in press). Meteorological and volcanological causes for these differences in plume halogen evolution (hence impacts) are discussed. This has implications for wider atmospheric modelling efforts to quantify global impacts from volcanic halogen emissions and highlights the useful role of fully-flexible and computationally inexpensive models such as PlumeChem to inform larger (regional or global) model studies regarding model initialisation and particularly near-source plume chemistry.

Field Observations of Hydrodynamics, Sediment Transport, and Water and Sediment Quality in the Hudson-Raritan Estuary

NASA Astrophysics Data System (ADS)

Bruno, M. S.; Glenn, S.; Chant, R.; Rankin, K.; Korfiatis, G.; Dimou, N.; Creed, E.; Fullerton, B.; Pence, A.; Burke, P.; Haldeman, C.; Hires, R.; Hunter, E.

2002-12-01

The New York-New Jersey Harbor estuary system is of enormous ecological and economic importance to the region. The presence of toxic chemicals in the water and sediments results in reduced water quality, fisheries restrictions/advisories, and general adverse impacts to the estuarine ecosystem. The Port of New York and New Jersey is central to the economy of the region. However, in recent years, problems associated with the management of contaminated dredged material, including high costs and the lack of suitable disposal/use alternatives, have threatened to impact the volume of shipping in the Harbor. Sources of contaminants include atmospheric deposition, municipal and industrial wastewater treatment facilities, combined sewer and stormwater outfalls, and rainfall-induced runoff (non-point sources). In addition, Harbor sediments can act as a continuing source as they are re-suspended and moved throughout the system by both natural and man-made means. As part of the New Jersey Toxics Reduction Workplan, Stevens Institute of Technology and Rutgers University are conducting hydrodynamic, sediment transport, and water and suspended sediment quality measurements in Newark Bay, the Arthur Kill and the Kill van Kull. The goals of the project include: (1) collection of high resolution (event-driven and long-term) hydrodynamic, sediment transport and water and suspended sediment quality measurements for use in the assessment of the dominant physics of the system and in the development of a combined hydrodynamic-sediment transport-water/sediment quality model for the region. (2) identification of those tributaries to NY-NJ Harbor that are significant sources of the chemicals of concern, and evaluation of the importance of non-point sources and existing contaminated bottom sediments as sources of the chemicals of concern. (3) identification of point discharges that represent significant sources of the chemicals of concern. Observations were obtained over a two-year period, during 21 tributary flow "events", each having an approximate duration of 1 week. The measurement program included 3 fixed mooring stations and 5 shipboard locations. Each mooring consisted of an acoustic Doppler current profiler; a high-resolution pressure sensor; an OBS; a CTD; and a laser-based scatterometer. The ship-board measurements included vertical current profiles using a towed acoustic Doppler current profiler; CTD measurements; OBS measurements; suspended sediment concentration and particle size spectrum using a laser-based scatterometer; and chemical characterization of water and suspended sediment samples. The water and sediment quality measurements were obtained using a specially designed Trace Organics Platform Sampler. This sampler allowed for the measurement of low-level concentrations of PCBs (108 congeners), dioxins/furans, Pesticides, PAHs and metals (Hg, Cd, Pb). Preliminary analysis of the data has improved our understanding of the circulation and sediment transport patterns in this region of the estuary, including the influence of extreme tributary flow events, local winds, and anthropogenic effects such as port structures, vessels, and the navigation channels, and has identified the most highly contaminated reaches of the tributaries.

Integrating Terrestrial Time-Lapse Photography with Laser Scanning to Distinguish the Drivers of Movement at Sólheimajökull, Iceland

NASA Astrophysics Data System (ADS)

How, P.; James, M. R.; Wynn, P.

2014-12-01

Glacier movement is attributed to a sensitive configuration of driving forces. Here, we present an approach designed to evaluate the drivers of movement at Sólheimajökull, an outlet glacier from the Myrdalsjökull ice cap, Iceland, through combining terrestrial time-lapse photography and laser scanning (TLS). A time-lapse camera (a dSLR with intervalometer and solar-recharged battery power supply) collected hourly data over the summer of 2013. The data are subject to all the difficulties that are usually present in long time-lapse sequences, such as highly variable illumination and visibility conditions, evolving surfaces, and camera instabilities. Feature-tracking software [1] was used to: 1) track regions of static topography (e.g. the skyline) from which camera alignment could be continuously updated throughout the sequence; and 2) track glacial surface features for velocity estimation. Absolute georeferencing of the image sequence was carried out by registering the camera to a TLS survey acquired at the beginning of the monitoring period. A second TLS survey (July 2013) provided an additional 3D surface. By assuming glacial features moved in approximately planimetrically straight lines between the two survey dates, combining the two TLS surfaces with the monoscopic feature tracking allows 3D feature tracks to be derived. Such tracks will enable contributions from different drivers (e.g. surface melting) to be extracted, even in imagery that is acquired not perpendicular to glacier motion. At Sólheimajökull, our aim is to elucidate any volcanic contribution to the observed movement.[1] http://www.lancaster.ac.uk/staff/jamesm/software/pointcatcher.htm

Prevalence of alcohol and drugs among car and van drivers killed in road accidents in Norway: an overview from 2001 to 2010.

PubMed

Christophersen, Asbjørg S; Gjerde, Hallvard

2014-01-01

To examine the prevalence of alcohol and drugs in blood samples collected from car and van drivers killed in traffic accidents in Norway during the time period from 2001 to 2010. Blood samples (n = 676, 63% of all killed drivers) were analyzed for alcohol, psychoactive medications, and illicit drugs. The cutoff limits for positive results were set according to the new legislative limits under the Norwegian Road Traffic Act. The results were assessed in relation to sex and age, time of day and day of week, and single- versus multiple-vehicle and all investigated vehicle accidents. Alcohol or one or more drugs was detected in samples from 40.2 percent of all investigated drivers, with 28.7 percent showing blood concentrations of at least 5 times the legislative limits. For the investigated female drivers, the total prevalence was 24.0 percent. Among the single-vehicle accidents, alcohol or drugs was found in 63.8 percent of the cases, with 49.1 percent showing blood concentrations of at least 5 times the legislative limits. Alcohol was detected in 25.3 and 49.1 percent of samples from all investigated drivers and among drivers killed in single-vehicle accidents, respectively. Psychoactive medications were found in 14.4 and 17.7 percent and illicit drugs in 14.1 and 19.2 percent, respectively. The most commonly detected group of medications was benzodiazepines, and amphetamines and tetrahydrocannabinol were the most commonly detected illicit drugs. The prevalence of alcohol alone was highest among drivers under the age of 25, and the combination of alcohol with other drugs was highest among drivers under the age of 35. Drivers between the ages of 25 and 54 showed the highest prevalence of medications and/or illicit drugs without the presence of alcohol. The highest prevalence of alcohol or drugs was found among drivers killed in single-vehicle accidents on weeknights (83.8%) and on weekend nights (89.3%). The findings confirm that a large number of fatally injured drivers, in particular among drivers involved in single-vehicle accidents, had concentrations of alcohol or drugs above the new legislative limits introduced in 2012. In many cases, concentrations of at least 5 times the limits were found. The proportion of drivers killed who tested positive for alcohol or other drugs did not change during the study period; however, the total number of drivers killed per year decreased by about 20 percent. Some changes were also observed with regard to the types of benzodiazepines and amphetamines detected during the 10-year period.

Impact of dust deposition on the albedo of Vatnajökull ice cap, Iceland

NASA Astrophysics Data System (ADS)

Wittmann, Monika; Dorothea Groot Zwaaftink, Christine; Steffensen Schmidt, Louise; Guðmundsson, Sverrir; Pálsson, Finnur; Arnalds, Olafur; Björnsson, Helgi; Thorsteinsson, Throstur; Stohl, Andreas

2017-03-01

Deposition of small amounts of airborne dust on glaciers causes positive radiative forcing and enhanced melting due to the reduction of surface albedo. To study the effects of dust deposition on the mass balance of Brúarjökull, an outlet glacier of the largest ice cap in Iceland, Vatnajökull, a study of dust deposition events in the year 2012 was carried out. The dust-mobilisation module FLEXDUST was used to calculate spatio-temporally resolved dust emissions from Iceland and the dispersion model FLEXPART was used to simulate atmospheric dust dispersion and deposition. We used albedo measurements at two automatic weather stations on Brúarjökull to evaluate the dust impacts. Both stations are situated in the accumulation area of the glacier, but the lower station is close to the equilibrium line. For this site ( ˜ 1210 m a.s.l.), the dispersion model produced 10 major dust deposition events and a total annual deposition of 20.5 g m-2. At the station located higher on the glacier ( ˜ 1525 m a.s.l.), the model produced nine dust events, with one single event causing ˜ 5 g m-2 of dust deposition and a total deposition of ˜ 10 g m-2 yr-1. The main dust source was found to be the Dyngjusandur floodplain north of Vatnajökull; northerly winds prevailed 80 % of the time at the lower station when dust events occurred. In all of the simulated dust events, a corresponding albedo drop was observed at the weather stations. The influence of the dust on the albedo was estimated using the regional climate model HIRHAM5 to simulate the albedo of a clean glacier surface without dust. By comparing the measured albedo to the modelled albedo, we determine the influence of dust events on the snow albedo and the surface energy balance. We estimate that the dust deposition caused an additional 1.1 m w.e. (water equivalent) of snowmelt (or 42 % of the 2.8 m w.e. total melt) compared to a hypothetical clean glacier surface at the lower station, and 0.6 m w.e. more melt (or 38 % of the 1.6 m w.e. melt in total) at the station located further upglacier. Our findings show that dust has a strong influence on the mass balance of glaciers in Iceland.

Association genetics of oleoresin flow in loblolly pine: discovering genes and predicting phenotype for improved resistance to bark beetles and bioenergy potential

Treesearch

Jared W. Westbrook; Marcio F. R. Resende Jr.; Patricio Munoz; Alejandro R. Walker; Jill L. Wegrzyn; C. Dana Nelson; David B. Neale; Matias Kirst; Salvador A. Gezan; Gary F. Peter; John M. Davis

2013-01-01

In the last decade, outbreaks of bark beetles in coniferous forests of North America have caused unprecedented tree mortality and economic losses (Nowak et al., 2008; van Mantgem et al., 2009; Waring et al., 2009), converting forests that were previously atmospheric carbon sinks into carbon sources (Kurz et al., 2008). Native species of bark beetle rapidly kill healthy...

Iceland's Grímsvötn volcano erupts

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-05-01

About 13 months after Iceland's Eyjafjallajökull volcano began erupting on 14 April 2010, which led to extensive air traffic closures over Europe, Grímsvötn volcano in southeastern took its turn. Iceland's most active volcano, which last erupted in 2004 and lies largely beneath the Vatnajökull ice cap, began its eruption activity on 21 May, with the ash plume initially reaching about 20 kilometers in altitude, according to the Icelandic Meteorological Office. Volcanic ash from Grímsvötn has cancelled hundreds of airplane flights and prompted U.S. president Barack Obama to cut short his visit to Ireland. As Eos went to press, activity at the volcano was beginning to subside.

Colonization of maritime glacier ice by bdelloid Rotifera.

PubMed

Shain, Daniel H; Halldórsdóttir, Katrín; Pálsson, Finnur; Aðalgeirsdóttir, Guðfinna; Gunnarsson, Andri; Jónsson, Þorsteinn; Lang, Shirley A; Pálsson, Hlynur Skagfjörð; Steinþórssson, Sveinbjörn; Arnason, Einar

2016-05-01

Very few animal taxa are known to reside permanently in glacier ice/snow. Here we report the widespread colonization of Icelandic glaciers and ice fields by species of bdelloid Rotifera. Specimens were collected within the accumulation zones of Langjökull and Vatnajökull ice caps, among the largest European ice masses. Rotifers reached densities up to ∼100 individuals per liter-equivalent of glacier ice/snow, and were freeze-tolerant. Phylogenetic analyses indicate that glacier rotifers are polyphyletic, with independent ancestries occurring within the Pleistocene. Collectively, these data identify a previously undescribed environmental niche for bdelloid rotifers and suggest their presence in comparable habitats worldwide. Copyright © 2016 Elsevier Inc. All rights reserved.

The Benjamin Shock Tube Problem in KULL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulitsky, M

2005-08-26

The goal of the EZturb mix model in KULL is to predict the turbulent mixing process as it evolves from Rayleigh-Taylor, Richtmyer-Meshkov, or Kelvin-Helmholtz instabilities. In this report we focus on a simple example of the Richtmyer-Meshkov instability (which occurs when a shock hits an interface between fluids of different densities) without the complication of reshock. The experiment by Benjamin et al. involving a Mach 1.21 incident shock striking an air / SF6 interface, is a good one to model and understand before moving onto shock tubes that follow the growth of the turbulent mixing zone from first shock throughmore » well after reshock.« less

Glacier retreat and projected river regime changes in the hydrologically highly-coupled Virkisjökull catchment, Iceland

NASA Astrophysics Data System (ADS)

Flett, Verity; Kirkbride, Martin; Black, Andrew; Everest, Jez; MacDonald, Alan

2016-04-01

Virkisjökull, an outlet glacier of the Oræfajökull icecap in SE Iceland, currently has 60% glacier cover, though this is reducing due to glacier retreat. Intensive monitoring over the last 4 years includes measurement of measuring ice ablation, proglacial discharge, dye-tracing of flow pathways, and deployment of three automatic weather stations at altitudes up to 880 m. These data calibrate a distributed hydrological model (WaSIM) to project potential river regime during stages of glacier retreat. Results show: (1) glacier hypsometry sensitises the catchment to a disproportionately rapid increase in runoff as the snowline rises onto a gentle ice cap resulting in in a potential annual increase in river discharge of up to 37% (2) a dominantly channelized glacial drainage system in all seasons with a rapid runoff response to melt: englacial flow of 0.58 m s-1 is comparable to the proglacial river velocity; and (3) longer-term, reduced glacier cover and snow storage will lead to a discharge regime dominated by short-term precipitation events in all seasons, and a reduced influence of the seasonal meltwater discharge peak. The study demonstrates the importance of glacier hypsometry above the present ELA as an influence on catchment hydrological response to potential climate warming.

Charge structure in volcanic plumes: a comparison of plume properties predicted by an integral plume model to observations of volcanic lightning during the 2010 eruption of Eyjafjallajökull, Iceland.

PubMed

Woodhouse, Mark J; Behnke, Sonja A

Observations of volcanic lightning made using a lightning mapping array during the 2010 eruption of Eyjafjallajökull allow the trajectory and growth of the volcanic plume to be determined. The lightning observations are compared with predictions of an integral model of volcanic plumes that includes descriptions of the interaction with wind and the effects of moisture. We show that the trajectory predicted by the integral model closely matches the observational data and the model well describes the growth of the plume downwind of the vent. Analysis of the lightning signals reveals information on the dominant charge structure within the volcanic plume. During the Eyjafjallajökull eruption both monopole and dipole charge structures were observed in the plume. By using the integral plume model, we propose the varying charge structure is connected to the availability of condensed water and low temperatures at high altitudes in the plume, suggesting ice formation may have contributed to the generation of a dipole charge structure via thunderstorm-style ice-based charging mechanisms, though overall this charging mechanism is believed to have had only a weak influence on the production of lightning.

Wind-blown volcanic ash off Iceland

NASA Image and Video Library

2017-12-08

On September 16, 2013 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Aqua satellite passed over the southern tip of Iceland and captured a remarkable image dust plumes blowing hundreds of kilometers over the Atlantic Ocean. The westernmost plume is dark tan in color and so thick that the blue ocean waters are obscured from view near Iceland's coast. The eastern plume appears broader, thinner and light gray in color. According to the Icelandic Met Office, near the Mýrdalsjökull and Vatnajökull ice-caps there are vast glacial outwash plains which stretch from the glacial margins to the sea. These plains, formed by melt water from glaciers, are known as sandur. Strong northerly winds frequently blow dust from the sandur plains far from the shore. This particular dust plume originates to the east of the Mýrdalsjökull ice cap. The Katla volcano, one of the largest in Iceland, lies under the Mýrdalsjökull glacier and in the general region of the westernmost plume. Katla has a history of large, violent eruptions occurring on an average of every 50-100 years. The volcano has been increasingly restless since 1999, with increased seismicity in recent years. In 2011 a very small eruption was reported, with minimal damage. Because of the increasing restlessness and the dangerous nature of historic eruptions, the volcano is currently carefully monitored. None of the monitoring agencies reported eruption at Katla in mid-September of this year. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Tephra Layer From the Plinian Eruption in ™r‘faj”kull 1362, Southeast Iceland

NASA Astrophysics Data System (ADS)

Selbekk, R. S.

2002-12-01

Pyroclastic fallout from the 1362 eruption of ™r‘faj”kull forms one of the volcanic marker horizons of the North Atlantic. This contribution reports the mineralogical and geochemical characteristics of the ™r‘faj”kull 1362 fallout and its grain-size distribution. A non-rifting 120 km long volcanic lineament some 50 km east of the Eastern Rift-Zone of Iceland is defined by transitional and alkalic volcanic rocks resting unconformably on late Tertiary strata. ™r‘faj”kull which forms the southern termination of this off-rift liniment is an ice-covered stratovolcano (2200 masl) composed mostly of subglacially formed hyaloclastite ranging from basalts to rhyolites. The two historical (1100 yrs) eruptions of ™r‘faj”kull include a small explosive eruption in 1727 and a large devastating Plinian eruption associated with major lahars and a caldera collapse in 1362. Between 1 and 2 km3 dense rock equivalent or 5-10 km3 of rhyolitic pumice was erupted and the fallout was mainly towards ESE. Tentative modelling of the PT-conditions of the magma formation, based on glass/mineral equilibria, indicates that the source was a near-eutectic melt in equilibrium with fayalite, hedenbergite, oligoclase and hematite at some 0.2 GPa pressure. A profile through the fallout was sampled at elevation of about 1100 masl on the SE flank of the volcano. A deposit of 1.8 m thickness was collected in 14 units for examination of composition, mineralogy and grain-size distribution during the eruption. In the profile the fallout is fine grained vesicular glass (1-3% minerals, 3% lithic fragments) with bubble wall thickness in the low micron range. The high and even vesiculation of the glass indicates fast magma ascent and explains the extreme mechanical fragmentation within the eruptive column, yielding between 50 and 80 wt% of less than 0.25 mm grain size. A reconstruction of the Plinian phase, based on grain-size analysis and abundance of lithic fragments, reveals that the eruption proceeded in three successive phases. An initial explosion produced phreatomagmatic debris associated with up to 35% of lithic fragments. In distal facies of the fallout, the initial phase is recognised as pale brownish base of the otherwise white glassy layer. The material ejection proceeded in two largely similar phases. These phases are separated only by a transition in grain size distribution indicating a temporary lowering in the effusion rate.

Eruption of Eyjafjallajökull Volcano, Iceland

NASA Image and Video Library

2010-03-27

NASA Image acquired March 24, 2010 To learn more and to download a high res version of this image go here: earthobservatory.nasa.gov/IOTD/view.php?id=43252 Iceland’s Eyjafjallajökull Volcano burst into life for the first time in 190 years on March 20, 2010. A 500-meter- (2,000-foot) long fissure opened in the Fimmvörduháls pass to the west of the ice-covered summit of Eyjafjallajökull. Lava fountains erupted fluid magma, which quickly built several hills of bubble-filled lava rocks (scoria) along the vent. A lava flow spread northeast, spilling into Hrunagil Gully. This natural-color satellite image shows lava fountains, lava flows, a volcanic plume, and steam from vaporized snow. The image was acquired on March 24, 2010, by the Advanced Land Imager (ALI) aboard NASA’s Earth Observing-1 (EO-1) satellite. The lava fountains are orange-red, barely visible at the 10-meter (33-foot) resolution of the satellite. The scoria cones surrounding the fissure are black, as is the lava flow extending to the northeast. White volcanic gases escape from the vent and erupting lava, while a steam plume rises where the hot lava meets snow. (The bright green color along the edge of the lava flow is an artifact of the sensor.) The eruption of Eyjafjallajökull was presaged by a series of earthquakes starting in early March. Over time, the earthquakes rose towards the surface, and land near the volcano rose at least 40 millimeters (2 inches)—both indications that magma was moving underneath the volcano. The eruption continued through at least March 26th, and may continue for several more months. Previous eruptions in the area have caused flooding due to the melting of glacial ice (a Jökulhlaup), but the current eruption is in an area covered by winter snow, not permanent ice. Although some past eruptions of Eyjafjallajökull were followed by larger, explosive eruptions at nearby Katla Volcano, there is currently no sign of activity at Katla. NASA image by Robert Simmon, using ALI data from the EO-1 team. Caption by Robert Simmon. Instrument: EO-1 - ALI NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

The Impacts of Advancing Glaciers and Jökulhlaups on the 19th Century Farming Community in the Suðursveit District South of Vatnajökull Glacier, Iceland.

NASA Astrophysics Data System (ADS)

Sigurmundsson, F. S.; Gísladóttir, G.; Erlendsson, E.

2014-12-01

Few areas in Iceland were as vulnerable to climate changes during the 19th century as the region south of Vatnajökull glacier. The region was repeatedly affected by glacier advance and jökulhlaups (glacier outburst floods) during the Little Ice Age AD 1300-1900 (LIA). The land area between the glacier and the coast was occupied by farming community. The aim of this research is to quantify and map the size of lost vegetated area in the 19th century during the glacial advance in the climax of the LIA and the impact these events had on the community, land-use, ownership, value of estates and livelihood. This research employs historical written sources to investigate changes in the cultural and natural landscape. Historical data and field observations will be collected and stored in a GIS database designed for the research, allowing data to be analyzed and presented on maps. The first recorded impact on the settlement is from 1794 when the Breiðármerkurjökull outlet glacier advanced and devastated pastures and crofts belonging in west of the district. Seventy five years later, in 1868, the largest estate was completely destroyed by a jökulhlaup. In 1829 a farm site in the middle of the district was moved due to repeated jökulhlaup. The outlet glacier Brókarjökull initiated annual jökulhlaups during 1820 -1870, devastating pastures and hayfields and woodlands of a total of 3 prominent estates in the area (by 1200 ha), causing devaluation of 33-66% on these estates. In the eastern part extensive jökulhlaups changed the glacial river channel causing the river to flow over vast area devastating 80 % of the eastern most estate causing its abandonment in 1892. The climate change and accompanied hazards during the 19th century changed the landscape of the Suðursveit district significantly. By the turn of the 20thcentury the vegetated land in the district had been reduced by 35% and areas of sediments increased by 25% and glaciated area increased by 10%. These changes had severe impact on the farming society, people's livelihood and the value of estates. The project is funded by the Vinir Vatnajökull fund, Rannís fund (no: 120211021), Landsvirkjun Power Energy fund, the Kvískerfund, and the doctoral grants of the University of Iceland Research Fund

Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol.

PubMed

Horwell, C J; Baxter, P J; Hillman, S E; Calkins, J A; Damby, D E; Delmelle, P; Donaldson, K; Dunster, C; Fubini, B; Kelly, F J; Le Blond, J S; Livi, K J T; Murphy, F; Nattrass, C; Sweeney, S; Tetley, T D; Thordarson, T; Tomatis, M

2013-11-01

The six week eruption of Eyjafjallajökull volcano in 2010 produced heavy ash fall in a sparsely populated area of southern and south eastern Iceland and disrupted European commercial flights for at least 6 days. We adopted a protocol for the rapid analysis of volcanic ash particles, for the purpose of informing respiratory health risk assessments. Ash collected from deposits underwent a multi-laboratory physicochemical and toxicological investigation of their mineralogical parameters associated with bio-reactivity, and selected in vitro toxicology assays related to pulmonary inflammatory responses. Ash from the eruption of Grímsvötn, Iceland, in 2011 was also studied. The results were benchmarked against ash from Soufrière Hills volcano, Montserrat, which has been extensively studied since the onset of eruptive activity in 1995. For Eyjafjallajökull, the grain size distributions were variable: 2-13 vol% of the bulk samples were <4 µm, with the most explosive phases of the eruption generating abundant respirable particulate matter. In contrast, the Grímsvötn ash was almost uniformly coarse (<3.5 vol%<4 µm material). Surface area ranged from 0.3 to 7.7 m2 g(-1) for Eyjafjallajökull but was very low for Grímsvötn (<0.6 m2 g(-1)). There were few fibre-like particles (which were unrelated to asbestos) and the crystalline silica content was negligible in both eruptions, whereas Soufrière Hills ash was cristobalite-rich with a known potential to cause silicosis. All samples displayed a low ability to deplete lung antioxidant defences, showed little haemolysis and low acute cytotoxicity in human alveolar type-1 like epithelial cells (TT1). However, cell-free tests showed substantial hydroxyl radical generation in the presence of hydrogen peroxide for Grímsvötn samples, as expected for basaltic, Fe-rich ash. Cellular mediators MCP-1, IL-6, and IL-8 showed chronic pro-inflammatory responses in Eyjafjallajökull, Grímsvötn and Soufrière Hills samples, despite substantial differences in the sample mineralogy and eruptive styles. The value of the pro-inflammatory profiles in differentiating the potential respiratory health hazard of volcanic ashes remains uncertain in a protocol designed to inform public health risk assessment, and further research on their role in volcanic crises is warranted. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

New land, new opportunitites. Vegetation succession and soil formation within the heterogenous moraines formed by the Skaftafellsjökull and Breiðamerkurjökull outlet glaciers in Southeast Iceland.

NASA Astrophysics Data System (ADS)

Vilmundardóttir, Olga K.; Gísladóttir, Guðrún; Lal, Rattan

2016-04-01

Retreating glaciers expose heterogenous landscapes where primary vegetation succession becomes active. These glacier forelands are excellent sites to study the effects of landscape on vegetation establishment and the commencing soil formation. Where the location of the glacier terminus is known in time, a chronosequence can be established, thus allowing for assessing the role of time on both vegetation succession and soil development. In Iceland, glaciers have been more or less retreating since the end of the Little Ice Age in ~1890, exposing thick moraines mostly composed of ground basaltic material of volcanic origin. In a research from southeast Iceland, soil formation was studied in front of two outlet glaciers, Skaftafellsjökull and Breiðamerkurjökull, and the developing soil properties analyzed with regards to the age of the surface, vegetation, avifauna and topography. At Skaftafellsjökull, soils were sampled along three moraines of known age. The vegetation was dominated by mosses but dwarf shrubs and shrubs (willows and birch) characterized the older moraines. Vegetation cover and plant group cover was affected by the profile position (summit, shoulder, backslope, footslope, toeslope) and the shape of the topographic features (ridge, slope, depression). The cover was significantly greater in toeslopes and footslopes when compared to the backslopes and featured significantly more shrub cover. The vegetation cover was significantly denser in depressions than on ridges and slopes, predominantly comprising mosses and shrubs. On the other hand, macro-lichens predominated on ridges. The vegetation cover and soil properties showed the strongest relation between total vegetation cover, cover of mosses, macro-lichens and dwarf shrubs. The concentration of SOC, N and ammonium oxalate extractable Al increased significantly with increase in vegetation cover and showed similar trends of increase in the cover by mosses, macro-lichens and dwarf shrubs. Profile position and the topographic shape were also significantly connected with several of the soil properties studied. At Breiðamerkurjökull, similar trends were observed between vegetation and the underlying soil properties. There, the presence of seabirds, mainly the great skua and the Arctic skua, has created stark differences between the regular moraine environment and the 'bird mounds' that have formed at sites where the birds regularly perch and defecate. These sites were commonly found on the top of moraine ridges although they featured also on more level ground. They were characterized by vigorous growth of grasses, thick soil that contained amounts of carbon and nitrogen up to 16 times higher than in the surrounding moraines. The study shows that depressional features in the moraines are sites of the most rapid vegetation succession and soil formation, a result from abiotic factors such as higher moisture content and sheltered locations. The rates however are succeeded at sites where avifauna adds nutrients into the developing soil, creating point centered effects and affecting the biogeomorphic characteristics of the moraines.

Elucidating pharmacodynamic interaction of silver nanoparticle - topical deliverable antibiotics.

PubMed

Thirumurugan, G; Seshagiri Rao, J V L N; Dhanaraju, M D

2016-07-18

In order to exploit the potential benefits of antimicrobial combination therapy, we need a better understanding of the circumstances under which pharmacodynamic interactions expected. In this study, Pharmacodynamic interactions between silver nanoparticle (SNP) and topical antibiotics such as Cefazolin (CEF), Mupirocin (MUP), Gentamycin (GEN), Neomycin (NEO), Tetracycline (TET), Vancomycin (VAN) were investigated using the MIC test, Combination assay followed by Fractional Inhibitory concentration Index and Agar well diffusion method. SNP + MUP, SNP + NEO, SNP + VAN combinations showed Synergism (SN) and SNP + CEF, SNP + GEN, SNP + TET showed Partial synergism (PS) against Staphylococcus aureus. Four combinations (SNP + CEF, SNP + MUP, SNP + GEN, SNP + VAN) showed SN, SNP + TET showed PS and Indifferent effect (ID) were observed for SNP + NEO against Pseudomonas aeruginosa. SN was observed for SNP + CEF, SNP + GEN, SNP + NEO, SNP + TET and SNP + MUP showed ID, SNP + VAN showed PS against Escherichia coli. In addition, we elucidated the possible mechanism involved in the pharmacodynamic interaction between SNP-topical antibiotics by increased ROS level, membrane damage following protein release, K(+) leakage and biofilm inhibition. Thus, our findings support that conjugation of the SNP with topical antibiotics have great potential in the topical formulation when treating complex resistant bacterial infections and where there is a need of more concentration to kill pathogenic bacteria.

Elucidating pharmacodynamic interaction of silver nanoparticle - topical deliverable antibiotics

NASA Astrophysics Data System (ADS)

Thirumurugan, G.; Seshagiri Rao, J. V. L. N.; Dhanaraju, M. D.

2016-07-01

In order to exploit the potential benefits of antimicrobial combination therapy, we need a better understanding of the circumstances under which pharmacodynamic interactions expected. In this study, Pharmacodynamic interactions between silver nanoparticle (SNP) and topical antibiotics such as Cefazolin (CEF), Mupirocin (MUP), Gentamycin (GEN), Neomycin (NEO), Tetracycline (TET), Vancomycin (VAN) were investigated using the MIC test, Combination assay followed by Fractional Inhibitory concentration Index and Agar well diffusion method. SNP + MUP, SNP + NEO, SNP + VAN combinations showed Synergism (SN) and SNP + CEF, SNP + GEN, SNP + TET showed Partial synergism (PS) against Staphylococcus aureus. Four combinations (SNP + CEF, SNP + MUP, SNP + GEN, SNP + VAN) showed SN, SNP + TET showed PS and Indifferent effect (ID) were observed for SNP + NEO against Pseudomonas aeruginosa. SN was observed for SNP + CEF, SNP + GEN, SNP + NEO, SNP + TET and SNP + MUP showed ID, SNP + VAN showed PS against Escherichia coli. In addition, we elucidated the possible mechanism involved in the pharmacodynamic interaction between SNP-topical antibiotics by increased ROS level, membrane damage following protein release, K+ leakage and biofilm inhibition. Thus, our findings support that conjugation of the SNP with topical antibiotics have great potential in the topical formulation when treating complex resistant bacterial infections and where there is a need of more concentration to kill pathogenic bacteria.

Using the Schur Complement to Reduce Runtime in KULL's Magnetic Diffusion Package

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunner, T A; Kolev, T V

2010-12-15

Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the fullmore » system. Significant improvements in the solution time are observed for several test problems.« less

Using a two-step matrix solution to reduce the run time in KULL's magnetic diffusion package

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brunner, T A; Kolev, T V

2010-12-17

Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the fullmore » system. Significant improvements in the solution time are observed for several test problems.« less

Blood and Oil: Vehicle Characteristics in Relation to Fatality Risk and Fuel Economy

PubMed Central

Robertson, Leon S.

2006-01-01

I examined the potential for a lower risk of death compatible with increased fuel economy among 67 models of 1999–2002 model year cars, vans, and sport-utility vehicles (SUVs) during the calendar years 2000 to 2004. The odds of death for drivers and all persons killed in vehicle collisions were related to vehicle weight, size, stability, and crashworthiness. I calculated that fatality rates would have been 28% lower and fuel use would have been reduced by 16% if vehicle weights had been reduced to the weight of vehicles with the lowest weight per size, where size is measured by the lateral distance needed to perform a 180-degree turn. If, in addition, all vehicles had crashworthiness and stability equal to those of the top-rated vehicles, more than half the deaths involving passenger cars, vans, and SUVs could have been prevented by vehicle modifications. PMID:17018814

Winter mass balance of Drangajökull ice cap (NW Iceland) derived from satellite sub-meter stereo images

NASA Astrophysics Data System (ADS)

Belart, Joaquín M. C.; Berthier, Etienne; Magnússon, Eyjólfur; Anderson, Leif S.; Pálsson, Finnur; Thorsteinsson, Thorsteinn; Howat, Ian M.; Aðalgeirsdóttir, Guðfinna; Jóhannesson, Tómas; Jarosch, Alexander H.

2017-06-01

Sub-meter resolution, stereoscopic satellite images allow for the generation of accurate and high-resolution digital elevation models (DEMs) over glaciers and ice caps. Here, repeated stereo images of Drangajökull ice cap (NW Iceland) from Pléiades and WorldView2 (WV2) are combined with in situ estimates of snow density and densification of firn and fresh snow to provide the first estimates of the glacier-wide geodetic winter mass balance obtained from satellite imagery. Statistics in snow- and ice-free areas reveal similar vertical relative accuracy (< 0.5 m) with and without ground control points (GCPs), demonstrating the capability for measuring seasonal snow accumulation. The calculated winter (14 October 2014 to 22 May 2015) mass balance of Drangajökull was 3.33 ± 0.23 m w.e. (meter water equivalent), with ∼ 60 % of the accumulation occurring by February, which is in good agreement with nearby ground observations. On average, the repeated DEMs yield 22 % less elevation change than the length of eight winter snow cores due to (1) the time difference between in situ and satellite observations, (2) firn densification and (3) elevation changes due to ice dynamics. The contributions of these three factors were of similar magnitude. This study demonstrates that seasonal geodetic mass balance can, in many areas, be estimated from sub-meter resolution satellite stereo images.

Reconstruction of the geometry of volcanic vents by trajectory tracking of fast ejecta - the case of the Eyjafjallajökull 2010 eruption (Iceland)

NASA Astrophysics Data System (ADS)

Dürig, Tobias; Gudmundsson, Magnus T.; Dellino, Pierfrancesco

2015-05-01

Two methods are introduced to estimate the depth of origin of ejecta trajectories (depth to magma level in conduit) and the diameter of a conduit in an erupting crater, using analysis of videos from the Eyjafjallajökull 2010 eruption to evaluate their applicability. Both methods rely on the identification of straight, initial trajectories of fast ejecta, observed near the crater rims before they are appreciably bent by air drag and gravity. In the first method, through tracking these straight trajectories and identifying a cut-off angle, the inner diameter and the depth level of the vent can be constrained. In the second method, the intersection point of straight trajectories from individual pulses is used to determine the maximum possible depth from which the tracked ejecta originated and the width of the region from which the pulses emanated. The two methods give nearly identical results on the depth to magma level in the crater of Eyjafjallajökull on 8 to 10 May of 51 ± 7 m. The inner vent diameter, at the level of origin of the pulses and ejecta, is found to have been 8 to 15 m. These methods open up the possibility to feed (near) real-time monitoring systems with otherwise inaccessible information about vent geometry during an ongoing eruption and help defining important eruption source parameters.

Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland

NASA Astrophysics Data System (ADS)

Smellie, J. L.; Walker, A. J.; McGarvie, D. W.; Burgess, R.

2016-08-01

Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations.

Vatnajökull meltwater discharge variability: a Holocene climate sensor in the Nordic Seas

NASA Astrophysics Data System (ADS)

Striberger, J.; Björck, S.; Ingólfsson, Ó.; Kjær, K.; Sandgren, P.; Snowball, I.

2009-04-01

The Holocene glacial history of Vatnajökull and its many outlet glaciers is rather poorly known, even though it is one of the largest ice caps outside Antarctica and Greenland. Vatnajökull is positioned in the centre of the Nordic Seas, the region for North Atlantic Deep Water formation and it is influenced by humid-bearing cyclone systems from the southwest. Thus, it can be regarded as a sensor for a combination of different climatic driven processes. Lake Lögurinn (53 km2, 20 m a.s.l), situated northeast of Vatnajökull, is part of the drainage system of Eyjabakkajökull, one of the most conspicuous surging outlet glaciers of the ice cap. In addition to glacial meltwater, the lake also receives discharge from rivers that drain non-glaciated catchments. The mix of glacial and non-glacial suspension makes the sediments suitable for analyses of how the fluvial regime has varied over time and how this relates to meltwater discharge, fluvial discharge and general changes in climate and hydrology. A total of 17.8 m of sediment was obtained from the central part of the northernmost sub-basin in Lake Lögurinn at water depths of 38 and 16 m, respectively. The sediments are laminated in most parts of the sequence. 137Cs analyses of the surface core have confirmed that the laminated couplets are varves. Tephra horizons have been used as time markers throughout the sediments, and X-ray fluorescence and X-ray analyses as well as visual observations have been used in order to identify varves in the uppermost 3.8 m of the sequence. This section covers the time period AD 1262-2005. The sediment contains 610 varves for the periods AD 1262-1476 and AD 1603-2005 (a total of 618 years). A significant change in sedimentation rate is observed between AD 1477-1602 (from 5.9 mm/yr to 1.2 mm/yr). For this period only 18 varves are found. This abrupt change is likely related to a lower discharge rate, or to more turbulent conditions in the lake. The sedimentation rate of the suspension delivered by the glacier-fed river correlates well to changes in Fe intensity, to changes in magnetic susceptibility and to changes in biogenic silica. The proxies show a cyclic pattern for the time period AD 1262-2005, each cycle spanning about 30-40 years, which could be related to a cyclic behaviour of the Eyjabakkajökull glacier. Possible explanations could be repeated surges, or recurring drainages of Háöldulón, an ice-dammed, lateral, partly supraglacial lake. Since AD 1890 surges have occurred about every 30-40 years, while the history of the ice-dammed lake is less known. The laminations and the cyclic pattern in the sediment parameters disappear gradually close to the H3 and H4 tephras and are not found below the H4 tephra. This implies that the current drainage system has been more or less stable for the past ca. 3000-4000 years, and that the sedimentation in Lake Lögurinn was less influenced by glacial meltwater during the early to mid-Holocene.

Seismic unrest at Katla Volcano- southern Iceland

NASA Astrophysics Data System (ADS)

jeddi, zeinab; Tryggvason, Ari; Gudmundsson, Olafur; Bödvarsson, Reynir; SIL Seismology Group

2014-05-01

Katla volcano is located on the propagating Eastern Volcanic Zone (EVZ) in South Iceland. It is located beneath Mýrdalsjökull ice-cap which covers an area of almost 600 km2, comprising the summit caldera and the eruption vents. 20 eruptions between 930 and 1918 with intervals of 13-95 years are documented at Katla which is one of the most active subglacial volcanoes in Iceland. Eruptions at Katla are mainly explosive due to the subglacial mode of extrusion and produce high eruption columns and catastrophic melt water floods (jökulhlaups). The present long Volcanic repose (almost 96 years) at Katla, the general unrest since 1955, and the 2010 eruption of the neighbouring Eyjafjallajökull volcano has prompted concerns among geoscientists about an imminent eruption. Thus, the volcano has been densely monitored by seismologists and volcanologists. The seismology group of Uppsala University as a partner in the Volcano Anatomy (VA) project in collaboration with the University of Iceland and the Icelandic Meteorological Office (IMO) installed 9 temporary seismic stations on and around the Mýrdalsjökull glacier in 2011. Another 10 permanent seismic stations are operated by IMO around Katla. The project's data collection is now finished and temporary stations were pulled down in August 2013. According to seismicity maps of the whole recording period, thousands of microearthquakes have occurred within the caldera region. At least three different source areas are active in Katla: the caldera region, the western Godaland region and a small cluster at the southern rim of Mýrdalsjökull near the glacial stream of Hafursarjökull. Seismicity in the southern flank has basically started after June 2011. The caldera events are mainly volcano-tectonic, while western and southern events are mostly long period (lp) and can be related to glacial or magmatic movement. One motivation of the VA Katla project is to better understand the physical mechanism of these lp events. Changes in seismicity arising from magma movement in the crust are characteristic properties of almost all active volcanoes. Meanwhile the study of the seismicity and propagation of elastic waves through the earth have the potential to give us important information about the internal structure of volcanoes. As very little is known of the 3D structure of Katla volcano and in order to define the 3D velocity structure and the geometry of the possible magma chamber, both P and S-wave travel time data from the most active period of seismicity (July-November 2011) are inverted simultaneously for both hypocenter locations and 3D velocity structure by using Local Earthquake Tomography (LET).

InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

NASA Astrophysics Data System (ADS)

Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

2014-12-01

Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and Síðujökull (Sí.) outlet glaciers. The black and grey arrows show the azimuth of the satellite and the look direction, respectively. (a) Wrapped interferogram showing the surge deformation (2π = 28.3 mm deformation). (b) Unwrapped interferogram with the black star as the reference area and negative values indicating line of sight lengthening (Auriac et al., 2014, doi:10.1093/gji/ggu205).

Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

NASA Astrophysics Data System (ADS)

Pappalardo, G.; Mona, L.; D'Amico, G.; Wandinger, U.; Adam, M.; Amodeo, A.; Ansmann, A.; Apituley, A.; Alados Arboledas, L.; Balis, D.; Boselli, A.; Bravo-Aranda, J. A.; Chaikovsky, A.; Comeron, A.; Cuesta, J.; De Tomasi, F.; Freudenthaler, V.; Gausa, M.; Giannakaki, E.; Giehl, H.; Giunta, A.; Grigorov, I.; Groß, S.; Haeffelin, M.; Hiebsch, A.; Iarlori, M.; Lange, D.; Linné, H.; Madonna, F.; Mattis, I.; Mamouri, R.-E.; McAuliffe, M. A. P.; Mitev, V.; Molero, F.; Navas-Guzman, F.; Nicolae, D.; Papayannis, A.; Perrone, M. R.; Pietras, C.; Pietruczuk, A.; Pisani, G.; Preißler, J.; Pujadas, M.; Rizi, V.; Ruth, A. A.; Schmidt, J.; Schnell, F.; Seifert, P.; Serikov, I.; Sicard, M.; Simeonov, V.; Spinelli, N.; Stebel, K.; Tesche, M.; Trickl, T.; Wang, X.; Wagner, F.; Wiegner, M.; Wilson, K. M.

2013-04-01

The eruption of the Icelandic volcano Eyjafjallajökull in April-May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET). Based on multi-wavelength Raman lidar systems, EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude. In this work we show the four-dimensional (4-D) distribution of the Eyjafjallajökull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April-26 May 2010). All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio) are stored in the EARLINET database available at http://www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org. During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the upper troposphere down to the local planetary boundary layer (PBL). After 19 April 2010, volcanic particles were detected over southern and south-eastern Europe. During the first half of May (5-15 May), material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. The last observations of the event were recorded until 25 May in Central Europe and in the Eastern Mediterranean area. The 4-D distribution of volcanic aerosol layering and optical properties on European scale reported here provides an unprecedented data set for evaluating satellite data and aerosol dispersion models for this kind of volcanic events.

Effects of Accelerated Deglaciation on Chemical Characteristics of Sub-arctic Lakes and Rivers in South and West Iceland

NASA Astrophysics Data System (ADS)

Ritter, M.; Strock, K.; Edwards, B. R.

2017-12-01

Glaciers and their associated paraglacial landscapes have changed rapidly over the past century, and may see increased rates of melt as temperatures increase in high latitude environments. As glaciers recede, glacial meltwater subsidies increase to inland freshwater systems, influencing their structure and function. Evidence suggests melting ice influences the chemical characteristics of systems by providing nutrient subsidies, while inputs of glacial flour influence their physical structure by affecting temperature, reducing water clarity and increasing turbidity. Together, changes in physical and chemical structure of these systems have subsequent effects on biota, with the potential to lower taxonomic richness. This study characterized the chemistry of rivers and lakes fed by glacial meltwater in sub-arctic environments of Iceland, where there is limited limnological data. The survey characterized nutrient chemistry, dissolved organic carbon, and ion chemistry. We surveyed glacial meltwater from six glaciers in south and west Iceland, using the drainage basin of Gigjökull glacier along the southern coast as a detailed study area to examine the interactions between groundwater and surface runoff. The southern systems, within the Eastern Volcanic Zone, have minimal soil development and active volcanoes produce ash input to lakes. Lakes in the Western Volcanic Zone were more diverse, located in older bedrock with more extensively weathered soil. Key differences were observed between aquatic environments subsidized with glacial meltwater and those without. This included physical effects, such as lower temperatures and chemical effects such as lower conductivity and higher pH in glacially fed systems. In the drainage basin of Gigjökull glacier, lakes formed after the former lagoon was emptied and then partly refilled with debris from jokulhlaups during the 2010 Eyjafjallajökull eruption. These newly formed lakes resembled non-glacial melt systems despite receiving glacial melt via indirect pathways. The effects of changing glacial inputs to inland freshwater systems are complex, and will be felt over a wide range of time scales. The systems in Gigjökull basin suggest once systems no longer receive glacial surface water melt, they will experience rapid shifts in physical and chemical structure.

Frequency, triggering factors and possible consequences of mass movements on outlet glaciers in Iceland.

NASA Astrophysics Data System (ADS)

Saemundsson, Thorsteinn; Margeirsson, Guðbjörn

2016-04-01

During the last 15 years several mass movements of various size and origin, e.g. rock avalanches, rock slides and debris slides have been observed to have fall on outlet glaciers in Iceland. This should not come as a surprise in this type of glacial environment, but in a way it does. When looking at the history only few mass movements are recorded to have fall on outlet glaciers in Iceland, during the decades before the year 2000 or since 1960. This "lack of mass movements" can be explained by the fact that fewer observations and monitoring were done in the past, but is it so or are we seeing increasing activity? Looking at the distribution of the known mass movements, two activity periods cam be identified. The former one around 1970 and the second one starting around 2000 and is still ongoing. Both of these periods are characterized by warmer climate leading to retreating phases of glaciers. Two larger mass movements are known from these two retreating periods. The former one occurred in January 1967. Then a large rockslide fell on the snout and into the glacial lake of the Steinholtsjökull outlet glacier in the northern side of the Eyjafjallajökull ice cap. The rockslide broke up the snout of the glacier and caused large floodwave bursting down the Steinholtsdalur valley transporting large volume of sediments down its path. The later one occurred in 2007, when a large rockavalanche fell on the Morsárjökull outlet glacier, in the southern side of the Vatnajökull ice cap. The avalanche debris covered around 1/5 of the glacier surface. Today the retreat and thinning of glaciers in Iceland are extremely rapid. The consequences of such a rapid retreat are e.g. unstable valley slopes surrounding the outlet glaciers, both in loose sediments and bedrock, thawing of mountain permafrost and not least formation of glacial lakes in front of the rapid retreating ice margins. Such conditions can become extremely hazardous, as seen by the above mentioned examples, both for all infrastructure but not least for the rapidly increasing tourism in Iceland.

Laboratory tests for diagnosis of food allergy: advantages, disadvantages and future perspectives.

PubMed

Moneret-Vautrin, D A; Kanny, G; Frémont, S

2003-04-01

Numerous biological tests point to the diagnosis of food sensitization: detection of specific IgEs by Rast techniques, multi-detection assays, immunoblotting, screening of basophil activation (BAT or FAST), assays for leukotriene LTC4 release (CAST), measurement of plasma histamine, serum tryptase, serum ECP, urinary EDN, completed by mannitol-lactulose test evaluating intestinal permeability, assay of fecal IgEs, Rast for specific IgG4. Primary screening for anti-food IgEs by multi-detection assays seeks justification from insufficient clinical data and false positive tests are common in patients sensitized to pollens or latex, on account of in vitro cross reactivities (CR). Multiple CR explain positive Rast to vegetal food allergens in such patients. Biological tests should not be performed as the first line of diagnosis. In vivo sensitisation is assessed by positive prick-tests, demonstrating the bivalence of allergens, as well as the affinity of specific IgEs, two conditions necessary to bridge membrane bound specific IgEs, leading to the release of mediators. Prick-tests are closer to clinical symptoms than biological tests. However, the diagnosis of food allergy is based on standardised oral challenges. Exceptions are high levels of specific IgEs to egg (> 6 kUl/l), peanut (> 15 kUl/l), fish (> 20 kUl/l) and milk (> 32 kUl/l), reaching a 95% predictive positive value. Rast inhibition tests are useful to identify masked allergens in foods. Research developments will have impact on the development of new diagnostic tools: allergen mixes reinforcing a food extract by associated recombinant major allergens, multiple combination of recombinant allergens (chips) or tests with synthetic epitopes aimed a the prediction of recovery. Laboratory tests take place in the decision free for the diagnosis for the food allergy and the follow-up of the levels specific IgEs is a tool to assess outcome and contributes to predict recovery or persistent allergy. Up to now the significance of positive laboratory tests showing the implication of IgEs is at the crossroads of the allergist's and biologist's expertise.

Persistence of Animal and Human Glycopeptide-Resistant Enterococci on Two Norwegian Poultry Farms Formerly Exposed to Avoparcin Is Associated with a Widespread Plasmid-Mediated vanA Element within a Polyclonal Enterococcus faecium Population

PubMed Central

Johnsen, P. J.; Østerhus, J. I.; Sletvold, H.; Sørum, M.; Kruse, H.; Nielsen, K.; Simonsen, G. S.; Sundsfjord, A.

2005-01-01

The evolutionary processes responsible for the long-term persistence of glycopeptide-resistant Enterococcus faecium (GREF) in nonselective environments were addressed by genetic analyses of E. faecium populations in animals and humans on two Norwegian poultry farms that were previously exposed to avoparcin. A total of 222 fecal GREF (n = 136) and glycopeptide-susceptible (n = 86) E. faecium (GSEF) isolates were obtained from farmers and poultry on three separate occasions in 1998 and 1999. Pulsed-field gel electrophoresis (PFGE) and plasmid DNA analyses discerned 22 GREF and 32 GSEF PFGE types within shifting polyclonal animal and human E. faecium populations and indicated the presence of transferable plasmid-mediated vanA resistance, respectively. Examples of dominant, persistent GREF PFGE types supported the notion that environmentally well-adapted GREF types may counteract the reversal of resistance. PFGE analyses, sequencing of the purK housekeeping gene, and partial typing of vanA-containing Tn1546 suggested a common animal and human reservoir of glycopeptide resistance. Inverse PCR amplification and sequence analyses targeting the right end of the Tn1546-plasmid junction fragment strongly indicated the presence of a common single Tn1546-plasmid-mediated element in 20 of 22 GREF PFGE types. This observation was further strengthened by vanY-vanZ hybridization analyses of plasmid DNAs as well as the finding of a physical linkage between Tn1546 and a putative postsegregation killing system for seven GREF PFGE types. In conclusion, our observations suggest that the molecular unit of persistence of glycopeptide resistance is a common mobile plasmid-mediated vanA-containing element within a polyclonal GREF population that changes over time. In addition, we propose that “plasmid addiction systems” may contribute to the persistence of GREF in nonselective environments. PMID:15640183

Impact of the Eyjafjallajökull ash cloud: A newspaper perspective

NASA Astrophysics Data System (ADS)

Harris, Andrew J. L.; Gurioli, Lucia; Hughes, Elizabeth E.; Lagreulet, Sandra

2012-09-01

We carried out a content analysis of eight national newspapers published during a 10-day period spanning Eyjafjallajökull's 2010 air space closure. Our intent was to understand the amount and type of material published, and the contribution of volcanologists and emergency responders to this material. We selected the best selling broadsheets and tabloids from the UK, France, Italy and USA. A total area of 135,000 cm2 was devoted to Eyjafjallajökull. Of this, 33% dealt with social themes, followed by volcanological (24%), economic (17%), response (13%) and airline (8%) issues. If, however, we examine the sources providing information we find a very different situation. Altogether, 669 sources were cited as giving quotes, of which 33% were credited to the air industry, followed by public (22%), politicians (12%), volcanologists (9%), responders (8%) and economists (2%). We also recorded all word descriptors for the ash cloud and its effects, with a total of 5380 words being logged. Negative words were the most common, with stranded having the highest frequency (180); chaos appearing 57 times. Coverage, thus, tended to feature quotes from the air industry, and carry a negative air; at times being confusing and contradictory. This, coupled with the fact that volcanological pieces tended to be placed well down the reporting order, meant that the message was of a chaotic situation and response, the performance of those who could be ascribed blame, i.e., responsible government agencies, thus likely being perceived in a negative light.

Microbial communities in the subglacial waters of the Vatnajökull ice cap, Iceland

PubMed Central

Thór Marteinsson, Viggó; Rúnarsson, Árni; Stefánsson, Andri; Thorsteinsson, Thorsteinn; Jóhannesson, Tómas; Magnússon, Sveinn H; Reynisson, Eyjólfur; Einarsson, Bergur; Wade, Nicole; Morrison, Hilary G; Gaidos, Eric

2013-01-01

Subglacial lakes beneath the Vatnajökull ice cap in Iceland host endemic communities of microorganisms adapted to cold, dark and nutrient-poor waters, but the mechanisms by which these microbes disseminate under the ice and colonize these lakes are unknown. We present new data on this subglacial microbiome generated from samples of two subglacial lakes, a subglacial flood and a lake that was formerly subglacial but now partly exposed to the atmosphere. These data include parallel 16S rRNA gene amplicon libraries constructed using novel primers that span the v3–v5 and v4–v6 hypervariable regions. Archaea were not detected in either subglacial lake, and the communities are dominated by only five bacterial taxa. Our paired libraries are highly concordant for the most abundant taxa, but estimates of diversity (abundance-based coverage estimator) in the v4–v6 libraries are 3–8 times higher than in corresponding v3–v5 libraries. The dominant taxa are closely related to cultivated anaerobes and microaerobes, and may occupy unique metabolic niches in a chemoautolithotrophic ecosystem. The populations of the major taxa in the subglacial lakes are indistinguishable (>99% sequence identity), despite separation by 6 km and an ice divide; one taxon is ubiquitous in our Vatnajökull samples. We propose that the glacial bed is connected through an aquifer in the underlying permeable basalt, and these subglacial lakes are colonized from a deeper, subterranean microbiome. PMID:22975882

Interactions between mafic eruptions and glacial ice or snow: implications of the 2010 Eyjafjallajökull, Iceland, eruption for hazard assessments in the central Oregon Cascades

NASA Astrophysics Data System (ADS)

McKay, D.; Cashman, K. V.

2010-12-01

The 2010 eruption of Eyjafjallajökull, Iceland, demonstrated the importance of addressing hazards specific to mafic eruptions in regions where interactions with glacial ice or snow are likely. One such region is the central Oregon Cascades, where there are hundreds of mafic vents, many of which are Holocene in age. Here we present field observations and quantitative analyses of tephra deposits from recent eruptions at Sand Mountain, Yapoah Cone, and Collier Cone (all <4 ka). These deposits differ from typical Cascade cinder cone deposits in several ways. Most significantly, the Sand Mountain eruption produced a relatively large tephra blanket (~1 km3) that is unusually fine-grained: average clast size is 0.063 - 0.5 mm, in contrast to tephra from typical Cascade cinder cones, which are dominated by small lapilli-sized clasts rather than ash. The eruption of Eyjafjallajökull earlier this year prompted us to investigate the role that ice or snow may have played in the production of unusually fine-grained tephra during the Sand Mountain eruption. The eruption date of Sand Mountain is not well constrained, but it likely occurred during the Neoglacial phase of ice advance, which lasted from ~2 to 8 ka in the central Oregon Cascades (Marcott et al., 2009). During the Neoglacial, winter snowfall was likely ~23% greater and summer temperatures ~1.4°C cooler than present (Marcott, 2009). Although ice did not advance to the elevation of the Sand Mountain vents during this time, the eruption could have occurred through several meters of snow. We have also seen very fine-grained tephra at Yapoah Cone, which is located at a higher elevation and may have interacted with glacial ice. In addition to being characterized by unusually fine grainsize, the Yapoah tephra blanket is deposited directly on top of hyaloclastite in several locations. Tephra from Collier Cone is not characterized by unusually fine grainsize, but several sections of the deposit exhibit features that suggest deposition on top of, or interbedding with, snow that later melted away. Identification of features in mafic tephra that suggest interactions with glacial ice or snow has significant implications for regional volcanic hazard assessments. Specifically, the unique hazards posed by Eyjafjallajökull, especially hazards to air travel caused by unusually fine-grained tephra, could be repeated in the Cascades. Although glacial ice is presently limited to elevations above ~2300 m in the central Oregon Cascades, winter snowpack can exceed 5 m at elevations of ~1800 m and above. If a cinder cone eruption were to occur during winter months, interaction with snow could generate phreatomagmatic activity and outburst flooding similar to the 2010 eruption of Eyjafjallajökull, along with similar hazards to regional air travel and nearby infrastructure. For this reason, we suggest that seasonality should be an important consideration in volcanic hazard assessments for the central Oregon Cascades.

Changes in shear-wave splitting before volcanic eruptions

NASA Astrophysics Data System (ADS)

Liu, Sha; Crampin, Stuart

2015-04-01

We have shown that observations of shear-wave splitting (SWS) monitor stress-accumulation and stress-relaxation before earthquakes which allows the time, magnitude, and in some circumstances fault-plane of impending earthquakes to be stress-forecast. (We call this procedure stress-forecasting rather than predicting or forecasting to emphasise the different formalism.) We have stress-forecast these parameters successfully three-days before a 1988 M5 earthquake in SW Iceland, and identified characteristic anomalies retrospectively before ~16 other earthquakes in Iceland and elsewhere. SWS monitors microcrack geometry and shows that microcracks are so closely spaced that they verge on fracturing and earthquakes. Phenomena verging on failure in this way are critical-systems with 'butterfly wings' sensitivity. Such critical-systems are very common. The Earth is an archetypal complex heterogeneous interactive phenomenon and must be expected to be a critical-system. We claim this critical system as a New Geophysics of a critically-microcracked rock mass. Such critical systems impose a range of fundamentally-new properties on conventional sub-critical physics/geophysics, one of which is universality. Consequently it is expected that we observe similar stress-accumulation and stress-relaxation before volcanic eruptions to those before earthquakes. There are three eruptions where appropriate changes in SWS have been observed similar to those observed before earthquakes. These are: the 1996 Gjálp fissure eruption, Vatnajökull, Iceland; a 2001 flank eruption on Mount Etna, Sicily (reported by Francesca Bianco, INGV, Naples); and the 2010 Eyjafjajökull ash-cloud eruption, SW Iceland. These will be presented in the same normalised format as is used before earthquakes. The 1996 Gjálp eruption showed a 2½-month stress-accumulation, and a ~1-year stress-relaxation (attributed to the North Atlantic Ridge adjusting to the magma injection beneath the Vatnajökull Ice Cap). The 2001 flank eruption of Etna showed stress-accumulation and stress-relaxation typical of a small earthquake. However, the changes in SWS before the 2010 Eyjafjajökull Eruption, SW Iceland, showed the most distinctive correlations with earthquakes, as it was only ~90km-west of the 1988 M5 in SW Iceland, which was successfully stress-forecast. The behaviour of SWS before the M5 earthquake and the Eyjafjajökull flank (ash-cloud) eruption is almost identical both showing linear stress-accumulation increases, and linear stress-relaxation decreases to the earthquake and the onset of the flank eruption, respectively. There are comparable slopes and durations. We consider this strong confirmation of the universality property of the New Geophysics of a critically-microcracked Earth. Papers referring to these developments can be found in geos.ed.ac.uk/home/scrampin/opinion. Also see abstracts in EGU2015 Sessions: Crampin & Gao (SM1.1), Gao & Crampin (SM3.1), and Crampin & Gao (GD.1).

NASA Satellite Eyes Iceland Volcano Cauldron

NASA Image and Video Library

2010-04-18

On Saturday, April 17, 2010, NASA Earth Observing-1 EO-1 spacecraft obtained this pair of images of the continuing eruption of Iceland Eyjafjallajökull volcano. On the left, new black ash deposits are visible on the ground.

Zircon from historic eruptions in Iceland: reconstructing storage and evolution of silicic magmas

NASA Astrophysics Data System (ADS)

Carley, Tamara L.; Miller, Calvin F.; Wooden, Joseph L.; Bindeman, Ilya N.; Barth, Andrew P.

2011-10-01

Zoning patterns, U-Th disequilibria ages, and elemental compositions of zircon from eruptions of Askja (1875 AD), Hekla (1158 AD), Öræfajökull (1362 AD) and Torfajökull (1477 AD, 871 AD, 3100 BP, 7500 BP) provide insights into the complex, extended, histories of silicic magmatic systems in Iceland. Zircon compositions, which are correlated with proximity to the main axial rift, are distinct from those of mid-ocean ridge environments and fall at the low-Hf edge of the range of continental zircon. Morphology, zoning patterns, compositions, and U-Th ages all indicate growth and storage in subvolcanic silicic mushes or recently solidified rock at temperatures above the solidus but lower than that of the erupting magma. The eruptive products were likely ascending magmas that entrained a zircon "cargo" that formed thousands to tens of thousands of years prior to the eruptions.

Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

PubMed

Karbowska, Bozena; Zembrzuski, Wlodzimierz

2016-07-01

Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase.

Simulation of the dispersion of the Eyjafjallajökull plume over Europe with COSMO-ART in the operational mode

NASA Astrophysics Data System (ADS)

Vogel, H.; Förstner, J.; Vogel, B.; Hanisch, T.; Mühr, B.; Schättler, U.; Schad, T.

2013-05-01

An extended version of the German operational weather forecast model was used to simulate the ash dispersion during the eruption of the Eyjafjallajökull. Sensitivity runs show the ability of the model to simulate thin ash layers when an increased vertical resolution is used. Calibration of the model results with measured data allows for a quantitative forecast of the ash concentration. An independent comparison of the simulated number concentration of 3 μm particles and observations reveals nearly perfect agreement. However, this perfect agreement could only be reached after modification of the emissions. As an operational forecast was launched every six hours, a time-lagged ensemble was obtained. Hence, the probability of violation of a certain threshold can be calculated. This is valuable information for the forecasters advising the organizations responsible for the closing of the airspace.

A nanovehicle developed for treating deep-seated bacteria using low-dose X-ray.

PubMed

Pan, Chien-Lin; Chen, Ming-Hong; Tung, Fu-I; Liu, Tse-Ying

2017-01-01

Many non-antibiotic strategies, such as photocatalysis and photodynamic therapy, have been proposed to inhibit and/or kill bacteria. However, these approaches still have drawbacks such as insufficient bacterial specificity and the limited penetration depth of ultraviolet and near-infrared light. To overcome these limitations, we developed a bacteria-specific anti-bacterial technique via using low-dose X-ray. Graphene oxide quantum dots (GQDs, a multifunctional vehicle) conjugated with vancomycin (Van, a bacteria-targeting ligand) were assembled with Protoporphyrin IX (PpIX, a photo/radiation sensitizer) to yield a novel Van-GQDs/PpIX complex that specifically attached to Escherichia coli and efficiently generated intracellular reactive oxygen species following X-ray activation. Delivery using GQDs increased the PpIX/Van ratio in the target bacterial cell, damaged bacterial cell wall, and enhanced X-ray-induced PpIX activation. Hence, this approach allowed for the use of a low-dose X-ray to efficiently activate the Van-GQDs/PpIX complex to exert its bactericidal effects on Escherichia coli without damaging normal cells. Furthermore, the E. coli did not develop resistance to the proposed approach for at least 7 rounds of repeated administration during one week. Thus, this proposed vehicle exhibiting bacteria-specific X-ray-triggered toxicity is a promising alternative to antibiotics for treating serious bacterial infections occurring in deep-seated tissues/organs (e.g., osteomyelitis and peritonitis). Administration of antibiotics is the most common treatment modality for bacterial infections. However, in some cases, patient attributes such as age, health, tolerance to antibiotics do not allow for the use of high-dose antibiotics. In addition, some bacteria develop resistance to antibiotics because of improper and long-term use of these agents. Therefore, non-antibiotic strategies to treat deeply situated bacterial infections, such as osteomyelitis, are urgently needed for avoiding amputation. To date, several non-antibiotic approaches, such as Ag nanoparticles, graphene-based materials, photocatalysis, and photodynamic therapy have been proposed to inhibit and/or kill bacteria. However, the major challenges of photochemical strategies, specificity and limited penetration depth of light source, still remain for treating the deep-seated bacteria. To overcome these problems, we developed a novel nanovehicle that exerted toxic effects specifically on bacteria following activation by a deeply penetrative low-dose X-ray, without damaging normal cells. As such, it realizes a deeply photochemical route for treating the deep-seated bacteria. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

STUDY OF LAND USE ISSUES CHARACTERIZING THE AMBALAVAO-ANDRINGITRA REGION OF MADAGASCAR

EPA Science Inventory

EPA Identifier: GF9500572
Title: Study of Land Use Issues Characterizing the Ambalavao-Andringitra Region of Madagascar
Fellow (Principal Investigator): Christian Arthur Kull
Institution: University of Colorado
EPA Grant Representati...

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

... erroneous impression that they are below the land surface. A quantitative computer analysis is necessary to separate out wind and height. ... MD. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center in Hampton, VA. Image ...

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

... causes motion of the plume features between camera views. A quantitative computer analysis is necessary to separate out wind and height ... MD. The MISR data were obtained from the NASA Langley Research Center Atmospheric Science Data Center in Hampton, VA. Image ...

The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations

NASA Astrophysics Data System (ADS)

Steffensen Schmidt, Louise; Aðalgeirsdóttir, Guðfinna; Guðmundsson, Sverrir; Langen, Peter L.; Pálsson, Finnur; Mottram, Ruth; Gascoin, Simon; Björnsson, Helgi

2017-07-01

A simulation of the surface climate of Vatnajökull ice cap, Iceland, carried out with the regional climate model HIRHAM5 for the period 1980-2014, is used to estimate the evolution of the glacier surface mass balance (SMB). This simulation uses a new snow albedo parameterization that allows albedo to exponentially decay with time and is surface temperature dependent. The albedo scheme utilizes a new background map of the ice albedo created from observed MODIS data. The simulation is evaluated against observed daily values of weather parameters from five automatic weather stations (AWSs) from the period 2001-2014, as well as in situ SMB measurements from the period 1995-2014. The model agrees well with observations at the AWS sites, albeit with a general underestimation of the net radiation. This is due to an underestimation of the incoming radiation and a general overestimation of the albedo. The average modelled albedo is overestimated in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and not taking the surface darkening from dirt and volcanic ash deposition during dust storms and volcanic eruptions into account. A comparison with the specific summer, winter, and net mass balance for the whole of Vatnajökull (1995-2014) shows a good overall fit during the summer, with a small mass balance underestimation of 0.04 m w.e. on average, whereas the winter mass balance is overestimated by on average 0.5 m w.e. due to too large precipitation at the highest areas of the ice cap. A simple correction of the accumulation at the highest points of the glacier reduces this to 0.15 m w.e. Here, we use HIRHAM5 to simulate the evolution of the SMB of Vatnajökull for the period 1981-2014 and show that the model provides a reasonable representation of the SMB for this period. However, a major source of uncertainty in the representation of the SMB is the representation of the albedo, and processes currently not accounted for in RCMs, such as dust storms, are an important source of uncertainty in estimates of snow melt rate.

Ice cauldron formation during the initial phase of the Eyjafjallajökull eruption observed with an airborne SAR

NASA Astrophysics Data System (ADS)

Magnusson, E.; Gudmundsson, M. T.; Hognadottir, T.; Hoskuldsson, F.; Oddsson, B.

2010-12-01

We present images obtained by the Icelandic Coast Guard with an airborne Synthetic Aperture Radar (SAR) during the first hours and days of the subglacial eruption in Eyjafjallajökull. Cloud cover obscured the summit from view in the first three days of the eruption. Under these circumstances the SAR, being weather independent and able to see through ash plumes, was a particularly valuable tool. It provided a record of temporal development of ice cauldrons formed in the 200 m thick ice cover in the caldera, the 50-100 m thick ice on the southern slopes and disruption due to flooding in the northward facing outlet glacier Gígjökull. The eruption started 14 April, 2010, at 1:30 AM. The eruption apparently remained subglacial for some hours but a small plume was observed by aircraft around 6 AM. The first SAR radar images were obtained at 8:55 and a record of images obtained until 10:42 reveal the early development of ice cauldrons providing unique detail in how the eruption breaks new holes in the ice surface, allowing accurate estimates of ice melting rates in an explosive eruption. Widening of the cauldron around the most active crater on the first day of the eruption was 20-25 m/hour, indicating that heat transfer from magma to the ice walls of the cauldron was of order 2 x 106 W m-2. This heat transfer rate reduced fast as the cauldrons reached a width of 300-400 m. The eruption site was repeatedly surveyed with the same SAR during the next days. The images demonstrate how the surface cauldrons evolved and how the center of the eruption activity moved during the second day of the eruption. During the first days of the eruption holes formed in the surface of the Gígjökull glacier outlet, where the roof of flood water channels collapsed. The SAR images allows further understanding on the flood water mechanism by revealing that many of these holes were formed by an intensive flash flood on the second day of the eruption, presumably by hydraulic fracturing when basal water pressures significantly exceeded the ice load.

Assessing hazards to aviation from sulfur dioxide emitted by explosive Icelandic eruptions

NASA Astrophysics Data System (ADS)

Schmidt, Anja; Witham, Claire S.; Theys, Nicolas; Richards, Nigel A. D.; Thordarson, Thorvaldur; Szpek, Kate; Feng, Wuhu; Hort, Matthew C.; Woolley, Alan M.; Jones, Andrew R.; Redington, Alison L.; Johnson, Ben T.; Hayward, Chris L.; Carslaw, Kenneth S.

2014-12-01

Volcanic eruptions take place in Iceland about once every 3 to 5 years. Ash emissions from these eruptions can cause significant disruption to air traffic over Europe and the North Atlantic as is evident from the 2010 eruption of Eyjafjallajökull. Sulfur dioxide (SO2) is also emitted by volcanoes, but there are no criteria to define when airspace is considered hazardous or nonhazardous. However, SO2 is a well-known ground-level pollutant that can have detrimental effects on human health. We have used the United Kingdom Met Office's NAME (Numerical Atmospheric-dispersion Modelling Environment) model to simulate SO2 mass concentrations that could occur in European and North Atlantic airspace for a range of hypothetical explosive eruptions in Iceland with a probability to occur about once every 3 to 5 years. Model performance was evaluated for the 2010 Eyjafjallajökull summit eruption against SO2 vertical column density retrievals from the Ozone Monitoring Instrument and in situ measurements from the United Kingdom Facility for Airborne Atmospheric Measurements research aircraft. We show that at no time during the 2010 Eyjafjallajökull eruption did SO2 mass concentrations at flight altitudes violate European air quality standards. In contrast, during a hypothetical short-duration explosive eruption similar to Hekla in 2000 (emitting 0.2 Tg of SO2 within 2 h, or an average SO2 release rate 250 times that of Eyjafjallajökull 2010), simulated SO2 concentrations are greater than 1063 µg/m3 for about 48 h in a small area of European and North Atlantic airspace. By calculating the occurrence of aircraft encounters with the volcanic plume of a short-duration eruption, we show that a 15 min or longer exposure of aircraft and passengers to concentrations ≥500 µg/m3 has a probability of about 0.1%. Although exposure of humans to such concentrations may lead to irritations to the eyes, nose and, throat and cause increased airway resistance even in healthy individuals, the risk is very low. However, the fact that volcanic ash and sulfur species are not always collocated and that passenger comfort could be compromised might be incentives to provide real-time information on the presence or absence of volcanic SO2. Such information could aid aviation risk management during and after volcanic eruptions.

Production of mildly alkaline basalts at complex ocean ridge settings: Perspectives from basalts emitted during the 2010 eruption at the Eyjafjallajökull volcano, Iceland

NASA Astrophysics Data System (ADS)

Viccaro, Marco; Nicotra, Eugenio; Urso, Salvatore

2015-11-01

The early phase of the 2010 eruption at the Eyjafjallajökull volcano (Iceland) produced poorly evolved mildly alkaline basalts that have a signature more enriched with respect to the typically depleted basalts emitted at ocean ridges. The whole rock geochemistry of these basaltic magmas offers a great opportunity to investigate the mantle source characteristics and reasons leading to this enriched fingerprint in proximity of the ocean ridge system. Some basaltic products of Katla volcano, ∼25 km east of Eyjafjallajökull, have been chosen from the literature, as they display a similar mildly alkaline signature and can be therefore useful to explore the same target. Major and trace element variations of the whole rock suggest a very limited evolutionary degree for the 2010 Eyjafjallajökull products and the selected Katla magmas, highlighting the minor role played by differentiation processes such as fractional crystallization. Nevertheless, effects of the limited fractionation have been erased through re-equilibration of the major and trace element abundances at primary conditions. Concentrations of Th after re-equilibration have been assumed as indexes of the partial melting degree, given the high incompatibility of the element, and enrichment ratios calculated for each trace element. Especially for LILE (Rb, Ba, K, Sr), the pattern of resulting enrichment ratios well matches that obtained from fractional melting of peridotite bearing hydrous phases (amphibole/phlogopite). This put forward the idea that magmas have been generated through partial melting of enriched mantle domains where hydrous minerals have been stabilized as a consequence of metasomatic processes. Refertilization of the mantle has been attributed to intrusion of hydrous silicate melts and fractional crystallization of hydrous cumulates. These refertilizing melts, inherited from an ancient subducted oceanic crust, intruded into a depleted oceanic lithosphere that remained stored for a long time (hundreds of Ma or Ga) before being re-entrained in partial melting. This means that magmas could have acquired their main geochemical differences in response of the variable depletion/enrichment degree of the heterogeneous mantle portion tapped at rather shallow depth (≤100 km). Our finding is another tessera in the open debate on the plume-related vs. non plume-related origin of Icelandic magmatism.

Dissolved and particulate organic carbon in the melt water of Icelandic glaciers

NASA Astrophysics Data System (ADS)

Chifflard, Peter; Reiss, Martin

2017-04-01

Recently, glaciers have been recognized as unique ecosystems with potential effects on the global carbon cycle. Among other transport processes organic carbon stored in glacier ecosystems is released from the glaciers through melt at the glaciers surface that discharges into proglacial streams and finally into the ocean. Nevertheless, the potential role of glaciers in the carbon cycle remains poorly understood (Hood et al. 2015). One particular problem in this respect is that there is a lack in regional and global analysis of the total amount of organic carbon released from glaciers. Although, the release of organic carbon has been investigated in proglacial streams in Alaska, the European Alps and Greenland, to our knowledge, there is no information available for Icelandic proglacial streams. Thus, the aims of this study are: 1) to develop a first base information about the concentration of dissolved and particulate organic carbon (DOC and POC) in several Icelandic proglacial streams and 2) to detect the variability of DOC and POC along a proglacial stream from the glacier source to the mouth into the Atlantic Ocean. Therefore, a field trip was conducted between 23 and 31 July 2016, whereby, 25 water samples were taken. The sampling points cover melt water from the following Icelandic glaciers Vatnajökull, Langjökull, Hofsjökull, Myrdalsjökull and Tungnafellsjökull. Further water samples were taken along the river Hvitá starting at the glacier Langjökull and ending at the mouth into the Atlantic ocean in the southwest of Iceland. At every sample point electrical conductivity, water temperate and the pH-value were measured in situ using a calibrated portable water quality meter (Hanna Combo HI98129). The water samples (130 ml) were filtered using pre-combusted GF/F filters (Whatman, pore sizes 0.7 µm) and stored in a cooling box until the shipment to the laboratory of the Department for Geography, Philipps-University of Marburg. The DOC concentrations in the filtered water samples were measured using a TOC analyzer using high-temperature combustion of organic matter (OM) followed by thermal detection of CO2 (TOC-L, Shimadzu, Japan). POC was measured by determining mass lost upon combustion of the samples. Therefore all glass fiber membranes were dried after sampling at 65°C to a constant weight, reweighed to calculate the total suspended solids (TSS), combusted via heating the filter to 550° C and finally reweighed to calculate the amount of particulate organic matter. Spectroscopic characteristics were detected by using a spectrophotometer (ThermoFisher, Genesys 10S) for UV-VIS analysis and a fluorescence spectrometer (Shimadzu RF-6000) for fluorescence analysis. Spectroscopic indices will be calculated based on these UV-VIS and fluorescence data. First results show that the DOC-concentrations are very low and range from 0.113 mg/l to 0.937 mg/l. These concentrations are comparable with values measured in the melt water in other regions (Alaska, Greenland and European Alps) (Hood et al. 2015). POC concentrations range from 0.667 mg/l to 173.333 mg/l and exceed the DOC-concentration at every sampling location. This differences can be compared with results of the Greenland Ice Sheet, but not with some small glaciers in the European Alps, where the concentrations of DOC and POC more or less equal (Hood et al. 2015). Nevertheless, the export of POC plays a very important factor within the organic carbon export budget of glaciers in Iceland and further measurements are required. Hood, E., Battin, T. J., Fellman, J., O'Neel, S., & Spencer, R. G. (2015). Storage and release of organic carbon from glaciers and ice sheets. Nature Geoscience, 8(2), 91-96.

Iceland

Atmospheric Science Data Center

2013-04-17

... (visible in the lower right), and to several other lakes and geothermal areas. Hofsjökull (the Temple Glacier; 1760 meters) is the third ... the city, the "Bay of Smokes", is testimony to the region's geothermal activity. MISR was built and is managed by NASA's Jet Propulsion ...

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

... background maritime particles are typically tiny spherical liquid droplets. In the last panel, the plume stands out relative to the ... D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. The MISR data were obtained from the NASA ...

Applying 3D Dynamic Visualisation to (Palaeo) Geomorphic Reconstruction: Modelling a Tenth Century Jökulhlaup at Sólheimajökull Glacier, South Iceland.

NASA Astrophysics Data System (ADS)

Booth, Laura; Isaacs, John

2014-05-01

Jökulhlaup (glacial outburst floods) are caused by subglacial geothermal activity melting overlying ice, or by draining of ice-dammed lakes. They pose a recurring hazard along Iceland's south coast where volcano-glacial interactions create often unpredictable, high-magnitude floods. Gathering information about past floods is crucial for projecting findings to present day scenarios and developing future predictions for contemporary flood routes. Understanding the physical setting or surrounding environment is essential in palaeo-flood reconstruction as drainage routes are ultimately defined by local topography and changing ice cover. At Sólheimajökull glacier, which drains the southern portion of Mýrdalsjökull ice cap, field evidence has been collected of a Tenth Century flood, recorded in the Icelander's Landnámabók (Book of Settlements). It was an exceptional event in terms of generation, magnitude and geomorphic impact. Although now fragmented and piecemeal, many of its direct (and indirect) geomorphological and sedimentary markers are still relatively well preserved and have been identified, mapped and dated to unravel the sequence of events played out during this significant episode in the glacial history and complex regional flood chronology. VolcVis, an innovative, bespoke visualisation platform, is developed and applied for the first time in visualising volcanic jökulhlaup. The platform is created using the Microsoft XNA game development framework, which facilitates rapid game engine production by providing a set of tools utilising a managed runtime environment. VolcVis can render large amounts of data efficiently and still provide an extremely high level of interaction with the data being presented, including full freedom of motion. This enables synthesis and presentation of field results from Sólheimajökull in a novel way, creating an interactive, multi-perspective, three-dimensional (3D) prototype model. The platform combines Digital Elevation Models of the area with aerial photography to create a 3D virtual environment, which provides the basis for entering field data to the geomorphic reconstruction. The result is a visual simulation of Sólheimajökull's Tenth Century physical environment which places the flood into geomorphic and topographic context. The wider implications of developing this tool are many when considering its ease of use and first-person navigational controls. The animations allow immediate exposure to environments that are otherwise lost in reality. VolcVis is a powerful tool in bringing reconstructed palaeo-environments back to life, albeit in the virtual sphere. It allows a uniquely contemporary appreciation of an elapsed event; yet which was a critical episode in the geomorphic evolution of this dynamic region. When field data are pieced together into a simulation, they hold a greater cohesive strength, giving the results wider applicability and relevance to a range of users and decision-makers, serving both technical and nontechnical perspectives. VolcVis' ability to dynamically display field data presents new possibilities for generating hypotheses, and for data sharing with Icelandic hazard mitigation authorities and the general public.

Iceland: Eyjafjallajökull Volcano

Atmospheric Science Data Center

2013-04-17

... plume height map, which is retrieved at 1.1 kilometer (0.68 mile) horizontal resolution, and with vertical accuracy of about half a ... the plume reaches altitudes exceeding 8 kilometers (26,247 feet), descending to about 6 kilometers (19,685 feet) about 250 kilometers (155 ...

Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards: Part II. Validation of satellite-derived Volcanic Sulphur Dioxide Levels.

NASA Astrophysics Data System (ADS)

Koukouli, MariLiza; Balis, Dimitris; Dimopoulos, Spiros; Clarisse, Lieven; Carboni, Elisa; Hedelt, Pascal; Spinetti, Claudia; Theys, Nicolas; Tampellini, Lucia; Zehner, Claus

2014-05-01

The eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 turned the attention of both the public and the scientific community to the susceptibility of the European airspace to the outflows of large volcanic eruptions. The ash-rich plume from Eyjafjallajökull drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people and with a strong economic impact. This unparalleled situation revealed limitations in the decision making process due to the lack of information on the tolerance to ash of commercial aircraft engines as well as limitations in the ash monitoring and prediction capabilities. The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, was introduced to facilitate the development of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on comprehensive satellite-derived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and ground-based measurements. The validation of volcanic SO2 levels extracted from the sensors GOME-2/MetopA and IASI/MetopA are shown here with emphasis on the total column observed right before, during and after the Eyjafjallajökull 2010 eruptions. Co-located ground-based Brewer Spectrophotometer data extracted from the World Ozone and Ultraviolet Radiation Data Centre, WOUDC, were compared to the different satellite estimates. The findings are presented at length, alongside a comprehensive discussion of future scenarios.

Modulation of glacier ablation by tephra coverage from Eyjafjallajökull and Grímsvötn volcanoes, Iceland: an automated field experiment

NASA Astrophysics Data System (ADS)

Möller, Rebecca; Möller, Marco; Kukla, Peter A.; Schneider, Christoph

2018-01-01

We report results from a field experiment investigating the influence of volcanic tephra coverage on glacier ablation. These influences are known to be significantly different from those of moraine debris on glaciers due to the contrasting grain size distribution and thermal conductivity. Thus far, the influences of tephra deposits on glacier ablation have rarely been studied. For the experiment, artificial plots of two different tephra types from Eyjafjallajökull and Grímsvötn volcanoes were installed on a snow-covered glacier surface of Vatnajökull ice cap, Iceland. Snow-surface lowering and atmospheric conditions were monitored in summer 2015 and compared to a tephra-free reference site. For each of the two volcanic tephra types, three plots of variable thickness ( ˜ 1.5, ˜ 8.5 and ˜ 80 mm) were monitored. After limiting the records to a period of reliable measurements, a 50-day data set of hourly records was obtained, which can be downloaded from the Pangaea data repository (https://www.pangaea.de; doi:10.1594/PANGAEA.876656). The experiment shows a substantial increase in snow-surface lowering rates under the ˜ 1.5 and ˜ 8.5 mm tephra plots when compared to uncovered conditions. Under the thick tephra cover some insulating effects could be observed. These results are in contrast to other studies which depicted insulating effects for much thinner tephra coverage on bare-ice glacier surfaces. Differences between the influences of the two different petrological types of tephra exist but are negligible compared to the effect of tephra coverage overall.

The impact of volcanic tephra on weathering and soil development of Icelandic Histosols, SE Iceland

NASA Astrophysics Data System (ADS)

Bonatotzky, Theresa; Ottner, Franz; Gísladóttir, Guðrún

2017-04-01

A mixture of poorly decomposed plant remains, crystalline volcanic material and intense aeolian deposition sets Icelandic Histosols apart from other Histosols in the northern hemisphere. They exhibit a unique combination of histic (organic) and andic soil characteristics. Allophane, imogolite and ferrihydrite are common minerals in Icelandic soils while layer silicates are rare. The volcanically active area south of Vatnajökull has received numerous tephra deposits of varying thickness during Holocene. Two distinct tephra layers, the light coloured rhyolitic tephra from the Öræfajökull eruption in AD 1362 and a black basaltic tephra from a Veiðivötn fissure eruption within the Bárðarbunga volcanic system in AD 1477, are well preserved in the soils. This provides a unique opportunity to study weathering behaviour of tephra deposits of different composition and to examine their contrasting mineralogy and impact on soils south of Vatnajökull glacier. The investigated soils can be classified as Histosols with plant residues as parent material and influenced by volcanic ejecta (tephra) and aeolian material. Low pH (H2O) and high organic matter (OM) content are the two dominating factors influencing their weathering behaviour. The soil organic carbon (SOC) content was found to between 16 - 31%. As OM inhibits the formation of amorphous secondary minerals, the clay content in Icelandic soils is generally low while Al-humus complexes are predominant. The soil horizons developed from rhyolitic and basaltic tephra both show differences. Investigations of the mineralogy show small evidence of weathering in the basaltic V1477 tephra, whereas the rhyolitic volcanic ejecta has hardly altered since its formation.

Mental health effects following the eruption in Eyjafjallajökull volcano in Iceland: A population-based study.

PubMed

Gissurardóttir, Ólöf Sunna; Hlodversdóttir, Heidrun; Thordardóttir, Edda Bjork; Pétursdóttir, Gudrún; Hauksdóttir, Arna

2018-01-01

Volcanic eruptions and other natural disasters may affect survivor's physical and mental health. The aim of this study was to examine the mental health effects of the 2010 Eyjafjallajökull volcanic eruption in Iceland on nearby residents, by exposure level and experience. This population-based study included 1615 residents living in an area close to the Eyjafjallajökull volcano at the time of the eruption and a sample of 697 residents from a non-exposed area. All participants received a questionnaire 6-9 months after the eruption assessing mental health (GHQ-12, PSS-4 and PC-PTSD). The exposed group also received questions related to the experience of the eruption. Replies were received from 1146 participants in the exposed group (71%) and 510 participants in the non-exposed group (73%). Compared to the non-exposed group, participants living in the high-exposed area were at increased risk of experiencing mental distress (GHQ) 6-9 months following the eruption (odds ratio (OR) 1.45%; 95% confidence interval (CI) 1.11-1.90). High-exposed participants were furthermore at increased risk of experiencing symptoms of post-traumatic stress disorder (PTSD) compared to those living in the low-exposed area (OR 3.71; 95% CI 1.34-15.41). We further found that those who had direct experience of the eruption were more likely to suffer from symptoms of mental distress, PTSD symptoms and perceived stress, compared to those less exposed. The findings indicate that screening for these factors (e.g. experience of the event) could potentially aid in identifying those most vulnerable to developing psychological morbidity after this unique type of disaster.

Spatial distribution of erosion and deposition during a glacier surge: Brúarjökull, Iceland

NASA Astrophysics Data System (ADS)

Korsgaard, Niels J.; Schomacker, Anders; Benediktsson, Ívar Örn; Larsen, Nicolaj K.; Ingólfsson, Ólafur; Kjær, Kurt H.

2015-12-01

Time-series of digital elevation models (DEMs) of the forefield of the Brúarjökull surge-type glacier in Iceland were used to quantify the volume of material that was mobilized by the 1963-1964 surge. The DEMs were produced by stereophotogrammetry on aerial photographs from before the surge (1961) and after (1988 and 2003). The analysis was performed on two DEMs of Difference (DoDs), i.e., a 1961-2003 DoD documenting the impact of the surge and a 1988-2003 DoD documenting the post-surge modification of the juvenile surging glacier landsystem. Combined with a digital geomorphological map, the DoDs allow us to quantify the impact of the surge on a landsystem scale down to individual landforms. A total of 34.2 ± 11.3 × 106 m3 of material was mobilized in the 30.7-km2 study area as a result of the most recent surge event. Of these, 17.4 ± 6.6 × 106 m3 of the material were eroded and 16.8 ± 4.7 × 106 m3 were deposited. More than half of the deposited volume was ice-cored landforms. This study demonstrates that although the total mobilized mass volume is high, the net volume gain of ice and sediment deposited as landforms in the forefield caused by the surge is low. Furthermore, deposition of new dead-ice from the 1963-1964 surge constitutes as much as 64% of the volume gain in the forefield. The 1988-2003 DoD is used to quantify the melt-out of this dead-ice and other paraglacial modification of the recently deglaciated forefield of Brúarjökull.

Long-range acoustic observations of the Eyjafjallajökull eruption, Iceland, April-May 2010

NASA Astrophysics Data System (ADS)

Matoza, Robin S.; Vergoz, Julien; Le Pichon, Alexis; Ceranna, Lars; Green, David N.; Evers, Läslo G.; Ripepe, Maurizio; Campus, Paola; Liszka, Ludwik; Kvaerna, Tormod; Kjartansson, Einar; Höskuldsson, Ármann

2011-03-01

The April-May 2010 summit eruption of Eyjafjallajökull, Iceland, was recorded by 14 atmospheric infrasound sensor arrays at ranges between 1,700 and 3,700 km, indicating that infrasound from modest-size eruptions can propagate for thousands of kilometers in atmospheric waveguides. Although variations in both atmospheric propagation conditions and background noise levels at the sensors generate fluctuations in signal-to-noise ratios and signal detectability, array processing techniques successfully discriminate between volcanic infrasound and ambient coherent and incoherent noise. The current global infrasound network is significantly more dense and sensitive than any previously operated network and signals from large volcanic explosions are routinely recorded. Because volcanic infrasound is generated during the explosive release of fluid into the atmosphere, it is a strong indicator that an eruption has occurred. Therefore, long-range infrasonic monitoring may aid volcanic explosion detection by complementing other monitoring technologies, especially in remote regions with sparse ground-based instrument networks.

Volcanic ash as an oceanic iron source and sink

NASA Astrophysics Data System (ADS)

Rogan, Nicholas; Achterberg, Eric P.; Le Moigne, Frédéric A. C.; Marsay, Chris M.; Tagliabue, Alessandro; Williams, Richard G.

2016-03-01

Volcanic ash deposition to the ocean forms a natural source of iron (Fe) to surface water microbial communities. Inputs of lithogenic material may also facilitate Fe removal through scavenging. Combining dissolved Fe (dFe) and thorium-234 observations alongside modeling, we investigate scavenging of Fe in the North Atlantic following the Eyjafjallajökull volcanic eruption. Under typical conditions biogenic particles dominate scavenging, whereas ash particles dominate during the eruption. The size of particles is important as smaller scavenging particles can become saturated with surface-associated ions. Model simulations indicate that ash deposition associated with Eyjafjallajökull likely led to net Fe removal. Our model suggests a threefold greater stimulation of biological activity if ash deposition had occurred later in the growing season when the region was Fe limited. The implications of ash particle scavenging, eruption timing, and particle saturation need to be considered when assessing the impact of ash deposition on the ocean Fe cycle and productivity.

Time-lagged ensemble simulations of the dispersion of the Eyjafjallajökull plume over Europe with COSMO-ART

NASA Astrophysics Data System (ADS)

Vogel, H.; Förstner, J.; Vogel, B.; Hanisch, T.; Mühr, B.; Schättler, U.; Schad, T.

2014-08-01

An extended version of the German operational weather forecast model was used to simulate the ash dispersion during the eruption of the Eyjafjallajökull. As an operational forecast was launched every 6 hours, a time-lagged ensemble was obtained. Sensitivity runs show the ability of the model to simulate thin ash layers when an increased vertical resolution is used. Calibration of the model results with measured data allows for a quantitative forecast of the ash concentration. After this calibration an independent comparison of the simulated number concentration of 3 μm particles and observations at Hohenpeißenberg gives a correlation coefficient of 0.79. However, this agreement could only be reached after additional modifications of the emissions. Based on the time lagged ensemble the conditional probability of violation of a certain threshold is calculated. Improving the ensemble technique used in our study such probabilities could become valuable information for the forecasters advising the organizations responsible for the closing of the airspace.

Inoculum Effects of Ceftobiprole, Daptomycin, Linezolid, and Vancomycin with Staphylococcus aureus and Streptococcus pneumoniae at Inocula of 105 and 107 CFU Injected into Opposite Thighs of Neutropenic Mice

PubMed Central

Lee, Dong-Gun; Murakami, Yoichi; Andes, David R.

2013-01-01

Reduced bactericidal efficacy at a high inoculum is known as the inoculum effect (IE). We used neutropenic mice to compare the IEs of ceftobiprole (CFB), daptomycin (DAP), linezolid (LZD), and vancomycin (VAN) against 6 to 9 strains of Staphylococcus aureus and 4 strains of Streptococcus pneumoniae at 2 inocula in opposite thighs of the same mice. Neutropenic mice had 104.5 to 105.7 CFU/thigh (low inoculum [LI]) in one thigh and 106.4 to 107.2 CFU/thigh (high inoculum [HI]) in the opposite thigh when treated for 24 h with subcutaneous (s.c.) doses every 12 h of DAP at 0.024 to 100 mg/kg of body weight and LZD at 0.313 to 320 mg/kg and s.c. doses every 6 h of CFB at 0.003 to 160 mg/kg and VAN at 0.049 to 800 mg/kg. Dose-response data were analyzed by a maximum effect (Emax) model using nonlinear regression. Static doses for each drug and at each inoculum were calculated, and the difference between HI and LI (IE index) gave the magnitude of IE for each drug-organism combination. Mean (range) IE indexes of S. aureus were 2.9 (1.7 to 4.6) for CFB, 4.1 (2.6 to 9.3) for DAP, 4.6 (1.7 to 7.1) for LZD, and 10.1 (6.3 to 20.3) for VAN. In S. pneumoniae, the IE indexes were 2.5 (1.3 to 3.3) for CFB, 2.0 (1.6 to 2.8) for DAP, 1.9 (1.7 to 2.2) for LZD, and 1.5 (0.8 to 3.2) for VAN; these values were similar for all drugs. In S. aureus, the IE was much larger with VAN than with CFB, DAM, and LZD (P < 0.05). An in vivo time course of vancomycin activity showed initiation of killing at 4- to 16-fold-higher doses at HI than at LI despite similar initial growth of controls. PMID:23295932

Predicting fire activity in the US over the next 50 years using new IPCC climate projections

NASA Astrophysics Data System (ADS)

Wang, D.; Morton, D. C.; Collatz, G. J.

2012-12-01

Fire is an integral part of the Earth system with both direct and indirect effects on terrestrial ecosystems, the atmosphere, and human societies (Bowman et al. 2009). Climate conditions regulate fire activities through a variety of ways, e.g., influencing the conditions for ignition and fire spread, changing vegetation growth and decay and thus the accumulation of fuels for combustion (Arora and Boer 2005). Our recent study disclosed the burned area (BA) in US is strongly correlated with potential evaporation (PE), a measurement of climatic dryness derived from National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR) climate data (Morton et al. 2012). The correlation varies spatially and temporally. With regard to fire of peak fire seasons, Northwestern US, Great Plains and Alaska have the strongest BA/PE relationship. Using the recently released the Global Fire Emissions Database (GFED) Version 3 (van der Werf et al. 2010), we showed increasing BA in the last decade in most of NCA regions. Longer time series of Monitoring Trends in Burn Severity (MTBS) (Eidenshink et al. 2007) data showed the increasing trends occurred in all NCA regions from 1984 to 2010. This relationship between BA and PE provides us the basis to predict the future fire activities in the projected climate conditions. In this study, we build spatially explicit predictors using the historic PE/BA relationship. PE from 2011 to 2060 is calculated from the Coupled Model Intercomparison Project Phase 5 (CMIP5) data and the historic PE/BA relationship is then used to estimate BA. This study examines the spatial pattern and temporal dynamics of the future US fires driven by new climate predictions for the next 50 years. Reference: Arora, V.K., & Boer, G.J. (2005). Fire as an interactive component of dynamic vegetation models. Journal of Geophysical Research-Biogeosciences, 110 Bowman, D.M.J.S., Balch, J.K., Artaxo, P., Bond, W.J., Carlson, J.M., Cochrane, M.A., D'Antonio, C.M., DeFries, R.S., Doyle, J.C., Harrison, S.P., Johnston, F.H., Keeley, J.E., Krawchuk, M.A., Kull, C.A., Marston, J.B., Moritz, M.A., Prentice, I.C., Roos, C.I., Scott, A.C., Swetnam, T.W., van der Werf, G.R., & Pyne, S.J. (2009). Fire in the Earth System. Science, 324, 481-484 Eidenshink, J., Schwind, B., Brewer, K., Zhu, Z.-L., Quayle, B., & Howard, S. (2007). A project for monitoring trends in burn severity. Fire Ecology Special Issue, 3 Morton, D.C., Collatz, G.J., Wang, D., Randerson, J.T., Giglio, L., & Chen, Y. (2012). Satellite-based assessment of climate controls on US burned area. Biogeosciences Discussion, 9, 7853-7892 van der Werf, G.R., Randerson, J.T., Giglio, L., Collatz, G.J., Mu, M., Kasibhatla, P.S., Morton, D.C., DeFries, R.S., Jin, Y., & van Leeuwen, T.T. (2010). Global fire emissions and the contribution of deforestation, savanna, forest, agricultural, and peat fires (1997-2009). Atmospheric Chemistry and Physics, 10, 11707-11735

The Vetter-Sturtevant Shock Tube Problem in KULL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulitsky, M S

2005-10-06

The goal of the EZturb mix model in KULL is to predict the turbulent mixing process as it evolves from Rayleigh-Taylor, Richtmyer-Meshkov, or Kelvin-Helmholtz instabilities. In this report we focus on an example of the Richtmyer-Meshkov instability (which occurs when a shock hits an interface between fluids of different densities) with the additional complication of reshock. The experiment by Vetter & Sturtevant (VS) [1], involving a Mach 1.50 incident shock striking an air/SF{sub 6} interface, is a good one to model, now that we understand how the model performs for the Benjamin shock tube [2] and a prototypical incompressible Rayleigh-Taylormore » problem [3]. The x-t diagram for the VS shock tube is quite complicated, since the transmitted shock hits the far wall at {approx}2 millisec, reshocks the mixing zone slightly after 3 millisec (which sets up a release wave that hits the wall at {approx}4 millisec), and then the interface is hit with this expansion wave around 5 millisec. Needless to say, this problem is much more difficult to model than the Bejamin shock tube.« less

Comparing Two Independent Satellite-Based Algorithms for Detecting and Tracking Ash Clouds by Using SEVIRI Sensor.

PubMed

Falconieri, Alfredo; Cooke, Michael C; Filizzola, Carolina; Marchese, Francesco; Pergola, Nicola; Tramutoli, Valerio

2018-01-27

The Eyjafjallajökull (Iceland) volcanic eruption of April-May 2010 caused unprecedented air-traffic disruption in Northern Europe, revealing some important weaknesses of current operational ash-monitoring and forecasting systems and encouraging the improvement of methods and procedures for supporting the activities of Volcanic Ash Advisory Centers (VAACs) better. In this work, we compare two established satellite-based algorithms for ash detection, namely RST ASH and the operational London VAAC method, both exploiting sensor data of the spinning enhanced visible and infrared imager (SEVIRI). We analyze similarities and differences in the identification of ash clouds during the different phases of the Eyjafjallajökull eruption. The work reveals, in some cases, a certain complementary behavior of the two techniques, whose combination might improve the identification of ash-affected areas in specific conditions. This is indicated by the quantitative comparison of the merged SEVIRI ash product, achieved integrating outputs of the RST ASH and London VAAC methods, with independent atmospheric infrared sounder (AIRS) DDA (dust-detection algorithm) observations.

Comparing Two Independent Satellite-Based Algorithms for Detecting and Tracking Ash Clouds by Using SEVIRI Sensor

PubMed Central

Cooke, Michael C.; Filizzola, Carolina

2018-01-01

The Eyjafjallajökull (Iceland) volcanic eruption of April–May 2010 caused unprecedented air-traffic disruption in Northern Europe, revealing some important weaknesses of current operational ash-monitoring and forecasting systems and encouraging the improvement of methods and procedures for supporting the activities of Volcanic Ash Advisory Centers (VAACs) better. In this work, we compare two established satellite-based algorithms for ash detection, namely RSTASH and the operational London VAAC method, both exploiting sensor data of the spinning enhanced visible and infrared imager (SEVIRI). We analyze similarities and differences in the identification of ash clouds during the different phases of the Eyjafjallajökull eruption. The work reveals, in some cases, a certain complementary behavior of the two techniques, whose combination might improve the identification of ash-affected areas in specific conditions. This is indicated by the quantitative comparison of the merged SEVIRI ash product, achieved integrating outputs of the RSTASH and London VAAC methods, with independent atmospheric infrared sounder (AIRS) DDA (dust-detection algorithm) observations. PMID:29382058

Eruption at Bardarbunga, Iceland

NASA Image and Video Library

2015-01-27

The main caldera of Bardarbunga volcano is tucked beneath Iceland’s largest glacier, Vatnajökull. Beginning in August, 2014, red-hot basaltic lava originating from Bardarbunga has been pouring from fissures just north of Vatnajökull, creating the massive Holuhraun lava field. As of January 6, 2015, the Holuhraun lava field had spread across more than 84 square kilometers (32 square miles), making it larger than the island of Manhattan. Holuhraun is Iceland’s largest basaltic lava flow since the Laki eruption in 1783–84, an event that killed 20 percent of the island’s population. Scientists from the University of Iceland’s Institute of Earth Sciences have estimated the thickness of the lava field based on data from surveillance flights. On average, the eastern part was about 10 meters (33 feet) thick, the center was 12 meters, and the western part was 14 meters. Their preliminary analysis put the volume of lava at 1.1 cubic kilometers, enough for the eruption to be considered a flood basalt. While Holuhraun continues to spew copious amounts of lava and sulfur dioxide, some observations suggest the eruption may be slowing down. As Edinburgh University volcanologist John Stevenson noted on his blog, Icelandic scientists have shown that the sinking (subsidence) of the caldera has declined from 80 centimeters (31 inches) to 25 centimeters per day—a sign that less magma is moving toward the surface. In addition, magnitude 5 or higher earthquakes that used to occur daily are now happening about once a week. Meanwhile, satellite observations of heat flux show a decline from more than 20 gigawatts in early September to fewer than 5 gigawatts by the end of November. As reported by Volcano Discovery, one bold scientist has even suggested that it is reasonable to forecast that the eruption may be over by March, 2015. The Moderate Resolution Imaging Spectrometer (MODIS) aboard NASA’s Aqua satellite flew over Iceland on January 18, 2015 and captured a false-color image of the lava field. In this image, clouds are bright white, cold snow is electric blue, and the North Atlantic Ocean is inky blue-black. Fresh lava appears bright red, while newly formed basaltic rock in the lava field, cooler than the fresh lava, appears black. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Intrusion triggering of the 2010 Eyjafjallajökull explosive eruption.

PubMed

Sigmundsson, Freysteinn; Hreinsdóttir, Sigrún; Hooper, Andrew; Arnadóttir, Thóra; Pedersen, Rikke; Roberts, Matthew J; Oskarsson, Níels; Auriac, Amandine; Decriem, Judicael; Einarsson, Páll; Geirsson, Halldór; Hensch, Martin; Ofeigsson, Benedikt G; Sturkell, Erik; Sveinbjörnsson, Hjörleifur; Feigl, Kurt L

2010-11-18

Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During such eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic, closing airspace over much of Europe for days. This eruption was preceded by an effusive flank eruption of basalt from 20 March to 12 April 2010. The 2010 eruptions are the culmination of 18 years of intermittent volcanic unrest. Here we show that deformation associated with the eruptions was unusual because it did not relate to pressure changes within a single magma chamber. Deformation was rapid before the first eruption (>5 mm per day after 4 March), but negligible during it. Lack of distinct co-eruptive deflation indicates that the net volume of magma drained from shallow depth during this eruption was small; rather, magma flowed from considerable depth. Before the eruption, a ∼0.05 km(3) magmatic intrusion grew over a period of three months, in a temporally and spatially complex manner, as revealed by GPS (Global Positioning System) geodetic measurements and interferometric analysis of satellite radar images. The second eruption occurred within the ice-capped caldera of the volcano, with explosivity amplified by magma-ice interaction. Gradual contraction of a source, distinct from the pre-eruptive inflation sources, is evident from geodetic data. Eyjafjallajökull's behaviour can be attributed to its off-rift setting with a 'cold' subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes, whereas immediate short-term eruption precursors may be subtle and difficult to detect.

Chemical conversion of sulphur dioxide on Eyjafjallajökull's volcanic ash from the 2010 eruption

NASA Astrophysics Data System (ADS)

Dupart, Yoan; Burel, Laurence; Delichere, Pierre; George, Christian; D'Anna, Barbara

2013-04-01

Volcanic eruptions induce important climatic and weather modifications. When volcanic ashes are emitted into the atmosphere they can travel for several weeks according to their size distribution and altitude of the emission. Eyjafjallajökull eruption, between April 14th and May 23th, is considered as a medium-size eruption. The upper level winds advected ashes over the UK and continental Europe. During volcanic eruptions high amounts of SO2 were injected into the atmosphere (from 50 to 200 ppbv)[1]. Previous works showed that SO2 could be convert into sulfate on mineral dust surfaces under dark conditions[2]. However, no conversion has been studied with real volcanic ashes and under day conditions (light exposure). For this study, real Eyjafjallajökull's ashes samples, collected on the 2010.04.18 at Seljavellir, were used. The ashes were deposited on a horizontal cylindrical coated-wall flow tube reactor surrounded by 5 fluorescent lamps (340-420 nm). The kinetic studies revealed that the presence of UV-A irradiation enhanced the conversion of SO2 on ashes samples. Moreover chemical analyses as XPS, Ion Chromatography and SEM were performed on volcanic ashes before and after exposition to SO2. XPS and ion chromatography analyzes showed that the presence of light increase the SO2 uptake on ashes surfaces and convert it into ions sulphate. Beside SEM analyses disclosed that the conversion takes place systematically on an iron oxide site . By combining kinetics and chemical analysis we are able to propose a new mechanism for the SO2 conversion on mineral surfaces under light conditions. 1. Self, S., et al., Volatile fluxes during flood basalt eruptions and potential effects on the global environment: A Deccan perspective. Earth and Planetary Science Letters, 2006. 248(1-2): p. 518-532. 2. Zhang et al., Heterogeneous Reactions of Sulfur Dioxide on Typical Mineral Particles, J. Phys. Chem. B, 2006

The 2010 Eyjafjallajökull and 2011 Grimsvötn ash plumes as seen by GPS

NASA Astrophysics Data System (ADS)

Grapenthin, R.; Hreinsdottir, S.; Gudmundsson, M. T.

2015-12-01

The injection of a volcanic plume introduces a dynamic, localized, short-term heterogeneity in the atmosphere. Satellite-imagery based remote sensing techniques provide good spatial coverage for the detection of such plumes, but slow satellite repeat times (>30 minutes) and cloud cover can delay, if not entirely prevent, the detection. GPS, in turn, provides excellent temporal coverage, but requires favorable satellite-station-geometry such that the signal propagates through the plume if it is to be used for plume detection and analysis. Two methods exist to detect / analyze ash plumes with GPS: (a) Ash-heavy plumes result in signal dispersion and hence a lowered signal-to-noise ratio (SNR). A lowered SNR, recorded by some receivers, can provide useful information about the plume, such as location and velocity of ascent. These data can be evaluated directly as they are recorded by the receiver; without the need of solving for a receiver's position. (b) Wet plumes refract the GPS signals piercing the plume and hence induce a propagation delay. When solving for a receiver position GPS analysis tools do not model this localized phase delay effect and solutions for plume-piercing satellites do not fit the data well. This can be exploited for plume analysis such as the estimation of changes to the atmospheric refractivity index. We analyze GPS data of the ~2 month 2010 Eyafjallajökull erption and the week-long 2011 Grímsvötn eruption to infer a first order estimate of plume geometry and its progression. Using SNR and phase delay information, we evaluate the evolution of the partitioning of wet versus dry parts of the plume. During the GPS processing we iteratively solve for phase-delay and position and fix other parameters, hence reducing the mapping of least-squares misfit into position estimates and other parameters. Nearly continuous webcam imagery provides independent observations of first-order plume characteristics for the Eyafjallajökull event.

The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: Evaluating the surface energy budget in a Regional Climate Model with automatic weather station observations

NASA Astrophysics Data System (ADS)

Steffensen Schmidt, Louise; Aðalgeirsdóttir, Guðfinna; Guðmundsson, Sverrir; Langen, Peter L.; Pálsson, Finnur; Mottram, Ruth; Gascoin, Simon; Björnsson, Helgi

2017-04-01

The evolution of the surface mass balance of Vatnajökull ice cap, Iceland, from 1981 to the present day is estimated by using the Regional Climate Model HIRHAM5 to simulate the surface climate. A new albedo parametrization is used for the simulation, which describes the albedo with an exponential decay with time. In addition, it utilizes a new background map of the ice albedo created from MODIS data. The simulation is validated against observed daily values of weather parameters from five Automatic Weather Stations (AWSs) from 2001-2014, as well as mass balance measurements from 1995-2014. The modelled albedo is overestimated at the AWS sites in the ablation zone, which we attribute to an overestimation of the thickness of the snow layer and the model not accounting for dust and ash deposition during dust storms and volcanic eruptions. A comparison with the specific summer, winter, and annual mass balance for all Vatnajökull from 1995-2014 shows a good overall fit during the summer, with the model underestimating the balance by only 0.04 m w. eq. on average. The winter balance, on the other hand, is overestimated by 0.5 m w. eq. on average, mostly due to an overestimation of the precipitation at the highest areas of the ice cap. A simple correction of the accumulation at these points reduced the error to 0.15 m w. eq. The model captures the evolution of the specific mass balance well, for example it captures an observed shift in the balance in the mid-1990s, which gives us confidence in the results for the entire model run. Our results show the importance of bare ice albedo for modelled mass balance and that processes not currently accounted for in RCMs, such as dust storms, are an important source of uncertainty in estimates of the snow melt rate.

Real time retrieval of volcanic cloud particles and SO2 by satellite using an improved simplified approach

NASA Astrophysics Data System (ADS)

Pugnaghi, Sergio; Guerrieri, Lorenzo; Corradini, Stefano; Merucci, Luca

2016-07-01

Volcanic plume removal (VPR) is a procedure developed to retrieve the ash optical depth, effective radius and mass, and sulfur dioxide mass contained in a volcanic cloud from the thermal radiance at 8.7, 11, and 12 µm. It is based on an estimation of a virtual image representing what the sensor would have seen in a multispectral thermal image if the volcanic cloud were not present. Ash and sulfur dioxide were retrieved by the first version of the VPR using a very simple atmospheric model that ignored the layer above the volcanic cloud. This new version takes into account the layer of atmosphere above the cloud as well as thermal radiance scattering along the line of sight of the sensor. In addition to improved results, the new version also offers an easier and faster preliminary preparation and includes other types of volcanic particles (andesite, obsidian, pumice, ice crystals, and water droplets). As in the previous version, a set of parameters regarding the volcanic area, particle types, and sensor is required to run the procedure. However, in the new version, only the mean plume temperature is required as input data. In this work, a set of parameters to compute the volcanic cloud transmittance in the three quoted bands, for all the aforementioned particles, for both Mt. Etna (Italy) and Eyjafjallajökull (Iceland) volcanoes, and for the Terra and Aqua MODIS instruments is presented. Three types of tests are carried out to verify the results of the improved VPR. The first uses all the radiative transfer simulations performed to estimate the above mentioned parameters. The second one makes use of two synthetic images, one for Mt. Etna and one for Eyjafjallajökull volcanoes. The third one compares VPR and Look-Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull volcano acquired by MODIS aboard the Aqua satellite on 11 May 2010 at 14:05 GMT.

Iceland

NASA Image and Video Library

2017-12-08

On August 22, 2014 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured a true-color image of a sunny summer day in Iceland. While most of the winter snow has melted to reveal green vegetation, the rugged northern peaks retain a snow cap. Further south bright white marks the location of glaciers. Situated in the southeast is Vatnajökull – the largest glacier in Europe and the site of Iceland’s highest mountain, Hvannadalshnjúkur. On August 20, scientists from the Icelandic Met Office closed all roads into the north of Vatnajökull Glacier due to increase seismic activity from the Bardarbunga volcano which lies under the ice cap in this area. On August 23, a small eruption was detected in Bardarbunga and the airspace near the activity was closed as a precautionary measure. Further study of the data suggested that no eruption had in fact occurred and airspace was opened under a code orange alert. Seismic activity remained high. On August 29, an eruption occurred north of Vatnajökull Glacier when a fissure, close to 1 km in length, opened up, and emitted lava at a slow pace. The eruption was short-lived, but on August 31 an eruption was confirmed in the same remote, uninhabited area. The Icelandic Meteorological Office reported that as of September 11 that eruption continued unabated. There has been no significant explosive activity, but lava flow has been the primary feature. High concentrations of sulfuric gases from the volcanic activity accompany the eruption, and are the primary health concern. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Ambient Noise Surface Wave Tomography of the volcanic systems of eastern Iceland

NASA Astrophysics Data System (ADS)

Green, R. G.; Priestley, K. F.; White, R. S.

2015-12-01

The Vatnajökull region of central-east Iceland lies above the head of the Iceland mantle plume where the crust is thickest due to enhanced melt supply. As a result the region contains a high density of volcanic rift systems, with six large subglacial central volcanoes. Due to the ice cover, the geological structure of the area and the location of past eruptions are poorly known. Imaging of the crustal velocity heterogeneities beneath the ice sheet aims to reveal much in terms of the structure of these volcanic plumbing systems. Mapping of significant velocity changes through time may also be indicative of movement of melt around the central volcanoes; one of which (Bárðarbunga) experienced a major rifting event in August 2014 (Sigmundsson et al. Nature 2015, Green et al. Nature Geosci. 2015). We present results from tomographic imaging of the volcanic systems in the region, using continuous data from a local broadband seismic network in central-east Iceland which provides excellent ray path coverage of the volcanic systems. This is supplemented by data from the HOTSPOT and ICEMELT experiments and the permanent monitoring stations of the Icelandic Meteorological Office. We process the continuous data following Benson et al. 2007 and automatic frequency-time analysis (FTAN) routines are used to extract more than 9000 dispersion measurements. We then generate Rayleigh wave group velocity maps which we present here. We find low velocity regions beneath the Vatnajökull icecap which are bounded by the surface expression of the volcanic rift systems. The lower velocities also extend north-west to the volcanic system under the Hofsjökull ice cap, and northwards towards Askja and the volcanic systems of the northern volcanic zone. We also produce locations and focal mechanisms of earthquakes caused by magmatic and hydrothermal activity to correlate structure with the activity of the volcanic systems.

Eruption of Eyjafjallajökull Volcano, Iceland May 2nd View

NASA Image and Video Library

2017-12-08

NASA satellite image acquired May 2, 2010 To view a detail of this image go to: www.flickr.com/photos/gsfc/4584266734/ Ash and steam continued billowing from Eyjafjallajökull Volcano in early May 2010. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image on May 2, 2010. The volcano’s summit is near the left edge of this image, capped by a dark plume. The plume is dull gray-brown, indicating that its principal visible component is volcanic ash. Ash from the plume blows toward the east-southeast, passing over a charcoal-colored ash field on the land surface. Just to the north of Eyjafjallajökull’s summit are white puffs of steam, likely from surface lava flows vaporizing snow and glacial ice. On May 4, 2010, the Icelandic Meteorological Office warned that Eyjafjallajökull showed no signs of ending its eruptive activity in the near future. The Met Office reported that ash from the volcano had reached a height of 5.8 to 6.0 kilometers (19,000 to 20,000 feet) above sea level, and had spread 65 to 80 kilometers (40 to 50 miles) east-southeast of the volcano, where it impeded visibility for local residents. The Met Office also reported that lava continued flowing down a steep hill north of the crater. NASA image by Robert Simmon, using ALI data from the EO-1 team. Caption by Michon Scott. Instrument: EO-1 – ALI To view other images from the Earth Observatory go to: earthobservatory.nasa.gov/ NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Eruption of Eyjafjallajökull Volcano, Iceland May 2nd View [Detail

NASA Image and Video Library

2017-12-08

NASA satellite image acquired May 2, 2010 To see the full view of this image go to: www.flickr.com/photos/gsfc/4584266582/ Ash and steam continued billowing from Eyjafjallajökull Volcano in early May 2010. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image on May 2, 2010. The volcano’s summit is near the left edge of this image, capped by a dark plume. The plume is dull gray-brown, indicating that its principal visible component is volcanic ash. Ash from the plume blows toward the east-southeast, passing over a charcoal-colored ash field on the land surface. Just to the north of Eyjafjallajökull’s summit are white puffs of steam, likely from surface lava flows vaporizing snow and glacial ice. On May 4, 2010, the Icelandic Meteorological Office warned that Eyjafjallajökull showed no signs of ending its eruptive activity in the near future. The Met Office reported that ash from the volcano had reached a height of 5.8 to 6.0 kilometers (19,000 to 20,000 feet) above sea level, and had spread 65 to 80 kilometers (40 to 50 miles) east-southeast of the volcano, where it impeded visibility for local residents. The Met Office also reported that lava continued flowing down a steep hill north of the crater. NASA image by Robert Simmon, using ALI data from the EO-1 team. Caption by Michon Scott. Instrument: EO-1 – ALI To view other images from the Earth Observatory go to: earthobservatory.nasa.gov/ NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

A survey of early health effects of the Eyjafjallajökull 2010 eruption in Iceland: a population-based study

PubMed Central

Carlsen, Hanne Krage; Gislason, Thorarinn; Benediktsdottir, Bryndis; Kolbeinsson, Thorir Bjorn; Hauksdottir, Arna; Thorsteinsson, Throstur

2012-01-01

Objective To estimate physical and mental health effects of the Eyjafjallajökull volcanic eruption on nearby residents. Design Cross-sectional study. Setting The Icelandic volcano Eyjafjallajökull erupted on 14 April 2010. The eruption lasted for about 6 weeks and was explosive, ejecting some 8 million tons of fine particles into the atmosphere. Due to prevailing winds, the ash spread mostly to the south and south-east, first over the rural region to the south, later over the Atlantic Ocean and Europe, closing European air space for several days. Participants Residents (n=207) of the most ash-exposed rural area south and east of the volcano. Methods The study period was from 31 May to 11 June 2010. Participants were examined by a physician. To ascertain respiratory health, standardised spirometry was performed before and after the use of a bronchodilator. All adult participants answered questionnaires about mental and physical health, their children's health and the use of protective equipment. Results Every other adult participant reported irritation in eyes and upper airway when exposed to volcanic ash. Adults (n=26) and children (n=5) with pre-existing asthma frequently reported worsening of their symptoms. No serious health problems requiring hospitalisation could be attributed to the eruption. The majority of the participants reported no abnormal physical or mental symptoms to the examining physician. Compared to an age- and gender-matched reference group, the ash-exposed participants reported lower smoking rates and were less likely to have ventilation impairment. Less than 10% of the participants reported symptoms of stress, anxiety or depression. Conclusions Short-term ash exposure was associated with upper airway irritation symptoms and exacerbation of pre-existing asthma but did not contribute to serious health problems. The exposure did not impair respiratory function compared to controls. Outdoor use of protective glasses and face masks was considered protective against irritation in eyes and upper airway. PMID:22403340

Numerical modeling of Drangajökull Ice Cap, NW Iceland

NASA Astrophysics Data System (ADS)

Anderson, Leif S.; Jarosch, Alexander H.; Flowers, Gwenn E.; Aðalgeirsdóttir, Guðfinna; Magnússon, Eyjólfur; Pálsson, Finnur; Muñoz-Cobo Belart, Joaquín; Þorsteinsson, Þorsteinn; Jóhannesson, Tómas; Sigurðsson, Oddur; Harning, David; Miller, Gifford H.; Geirsdóttir, Áslaug

2016-04-01

Over the past century the Arctic has warmed twice as fast as the global average. This discrepancy is likely due to feedbacks inherent to the Arctic climate system. These Arctic climate feedbacks are currently poorly quantified, but are essential to future climate predictions based on global circulation modeling. Constraining the magnitude and timing of past Arctic climate changes allows us to test climate feedback parameterizations at different times with different boundary conditions. Because Holocene Arctic summer temperature changes have been largest in the North Atlantic (Kaufman et al., 2004) we focus on constraining the paleoclimate of Iceland. Glaciers are highly sensitive to changes in temperature and precipitation amount. This sensitivity allows for the estimation of paleoclimate using glacier models, modern glacier mass balance data, and past glacier extents. We apply our model to the Drangajökull ice cap (~150 sq. km) in NW Iceland. Our numerical model is resolved in two-dimensions, conserves mass, and applies the shallow-ice-approximation. The bed DEM used in the model runs was constructed from radio echo data surveyed in spring 2014. We constrain the modern surface mass balance of Drangajökull using: 1) ablation and accumulation stakes; 2) ice surface digital elevation models (DEMs) from satellite, airborne LiDAR, and aerial photographs; and 3) full-stokes model-derived vertical ice velocities. The modeled vertical ice velocities and ice surface DEMs are combined to estimate past surface mass balance. We constrain Holocene glacier geometries using moraines and trimlines (e.g., Brynjolfsson, etal, 2014), proglacial-lake cores, and radiocarbon-dated dead vegetation emerging from under the modern glacier. We present a sensitivity analysis of the model to changes in parameters and show the effect of step changes of temperature and precipitation on glacier extent. Our results are placed in context with local lacustrine and marine climate proxies as well as with glacier extent and volume changes across the North Atlantic.

75 FR 32987 - Orders Limiting Scheduled Operations at John F. Kennedy International Airport and Newark Liberty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-10

... points in Europe canceled due to volcanic ash from April 27 through October 30, 2010. This policy is...- 7143; e-mail: [email protected] . SUPPLEMENTARY INFORMATION: Background On April 14, 2010, an eruption of the Eyjafjallaj[ouml]kull volcano in Iceland began releasing large quantities of volcanic ash into...

[Detection of pathogenic leptospira in the waste water and sewage sludge of large pig breeding sites].

PubMed

Mînzat, R M; Tomescu, V

1975-01-01

Sewage effluent and sludge from the purification plant of 8 large piggeries was examined for the presence of pathogenic leptospires. By using the methods of Appelman and Van Thiel it was found that 43.1% of samples of effluent were contaminated with L. pomona and O. tarassovi. Altogether 33 strains of pomona and three mixed cultures of pomona and tarassovi were obtained. The isolated strains were shown to be pathogenic by experimental infection of guinea-pigs, rabbits and pregnant and non-pregnant sows. The average period of survival of pathogenic leptospires in sewage effluent was 24 to 48 hours, with a maximum of 96 hours. Leptospires were killed within 24 hours in decanted sludge, owing to its strong acidity.

New START, Eyjafjallajökull, and Nuclear Winter

NASA Astrophysics Data System (ADS)

Robock, Alan

2010-11-01

On 8 April 2010, U.S. president Barack Obama and Russian president Dmitry Medvedev signed the Treaty Between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms, committing the United States and Russia to reducing their nuclear arsenals to levels less than 5% of the maximum during the height of the cold war in the 1980s. This treaty is called “New START,” as it is a follow-on to the 1991 Strategic Arms Reductions Treaty (START). On 14 April 2010 the Eyjafjallajökull volcano in Iceland began an explosive eruption phase that shut down air traffic in Europe for 6 days and continued to disrupt it for another month. What do these two events have in common? Nuclear weapons, when targeted at cities and industrial areas, would start fires, producing clouds of sooty smoke. Volcanic eruptions emit ash particles and sulfur dioxide (SO2), which forms sulfate aerosols in the atmosphere. Thus, both the use of nuclear weapons and volcanic eruptions produce particles that can be transported large distances from the source and can affect weather and climate.

Visualization Case Study: Eyjafjallajökull Ash (Invited)

NASA Astrophysics Data System (ADS)

Simmon, R.

2010-12-01

Although data visualization is a powerful tool in Earth science, the resulting imagery is often complex and difficult to interpret for non-experts. Students, journalists, web site visitors, or museum attendees often have difficulty understanding some of the imagery scientists create, particularly false-color imagery and data-driven maps. Many visualizations are designed for data exploration or peer communication, and often follow discipline conventions or are constrained by software defaults. Different techniques are necessary for communication with a broad audience. Data visualization combines ideas from cognitive science, graphic design, and cartography, and applies them to the challenge of presenting data clearly. Visualizers at NASA's Earth Observatory web site (earthobservatory.nasa.gov) use these techniques to craft remote sensing imagery for interested but non-expert readers. Images range from natural-color satellite images and multivariate maps to illustrations of abstract concepts. I will use imagery of the eruption of Iceland's Eyjafjallajökull volcano as a case study, showing specific applications of general design techniques. By using color carefully (including contextual data), precisely aligning disparate data sets, and highlighting important features, we crafted an image that clearly conveys the complex vertical and horizontal distribution of airborne ash.

Ash generation and distribution from the April-May 2010 eruption of Eyjafjallajökull, Iceland

PubMed Central

Gudmundsson, Magnús T.; Thordarson, Thorvaldur; Höskuldsson, Ármann; Larsen, Gudrún; Björnsson, Halldór; Prata, Fred J.; Oddsson, Björn; Magnússon, Eyjólfur; Högnadóttir, Thórdís; Petersen, Guðrún Nína; Hayward, Chris L.; Stevenson, John A.; Jónsdóttir, Ingibjörg

2012-01-01

The 39-day long eruption at the summit of Eyjafjallajökull volcano in April–May 2010 was of modest size but ash was widely dispersed. By combining data from ground surveys and remote sensing we show that the erupted material was 4.8±1.2·1011 kg (benmoreite and trachyte, dense rock equivalent volume 0.18±0.05 km3). About 20% was lava and water-transported tephra, 80% was airborne tephra (bulk volume 0.27 km3) transported by 3–10 km high plumes. The airborne tephra was mostly fine ash (diameter <1000 µm). At least 7·1010 kg (70 Tg) was very fine ash (<28 µm), several times more than previously estimated via satellite retrievals. About 50% of the tephra fell in Iceland with the remainder carried towards south and east, detected over ~7 million km2 in Europe and the North Atlantic. Of order 1010 kg (2%) are considered to have been transported longer than 600–700 km with <108 kg (<0.02%) reaching mainland Europe. PMID:22893851

Crash fatality and vehicle incompatibility in collisions between cars and light trucks or vans.

PubMed

Ossiander, Eric M; Koepsell, Thomas D; McKnight, Barbara

2014-12-01

In crashes between a car and a light truck or van (LTV), car occupants are more likely to be killed than LTV occupants. The extent this is due to the greater harm imposed by LTVs on cars or the greater protection they offer their own occupants is not known. We conducted a case-control study of collisions between two passenger vehicles in the USA during 1990-2008. Cases were all decedents in fatal crashes (N=157,684); one control was selected from each crash in a national probability sample of crashes (N=379,458). Adjusted for the type of vehicle they were riding in and other confounders, occupants of vehicles colliding with any type of LTVs (categorised as compact sport utility vehicles (SUV), full-size SUVs, minivans, full-size vans, compact pickups and full-size pickups) were at higher risk of death compared with occupants colliding with cars. Adjusted for the type of vehicle they crashed with and other confounders, occupants of LTVs in a collision with any vehicle were at lower risk of death compared with car occupants. Compared with a crash between two cars, the overall RR of death in a crash between any of the other 27 different combinations of vehicle types was 1.0 or greater, except for crashes between two full-size pickups, where the RR of death was 0.9. Although LTVs protect their own occupants better than cars do, LTVs are associated with an excess total risk of death in crashes with cars or other LTVs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Dynamics and Stability of Acoustic Wavefronts in the Ocean

DTIC Science & Technology

2014-09-30

processes on underwater acoustic fields. The 3-D HWT algorithm was also applied to investigate long- range propagation of infrasound in the atmosphere...oceanographic processes on underwater sound propagation and also has been demonstrated to be an efficient and robust technique for modeling infrasound ...algorithm by modeling propagation of infrasound generated by Eyjafjallajökull volcano in southern Iceland. Eruptions of this volcano were recorded by

Insights into the development of drumlin formation using ground-penetrating radar

NASA Astrophysics Data System (ADS)

Woodard, J.; Zoet, L.; Iverson, N. R.; Benediktsson, Í. Ö.; Schomacker, A.; Finlayson, A.

2016-12-01

Drumlins form as the result of subglacial slip, but the exact mechanisms responsible for their formation remain enigmatic. Resolution of drumlin internal stratigraphy provides a means for constraining the formation processes of drumlins, and thus the basal mechanics that result in their formation. Traditional litho-stratigraphic techniques have provided great insight into the internal stratigraphy of drumlins but are inherently limited to areas of natural exposure. We report on the application of geophysical methods used to image the internal stratigraphy of drumlins over a much larger area than is possible through litho-stratigraphic logging. Using ground penetrating radar we investigated the internal stratigraphy of seven drumlins from a recently exposed active drumlin field in the forefield of Múlajökull, Iceland. Data were collected using 100 and 200 MHz antennas that had maximum penetration depths of 15 m and 7 m with 0.4 m and 0.2 m resolution, respectively. Echograms demonstrated distinct layering of the diamictites. From the surface to ca. 2 m depth, till layers generally conformed to the longitudinal surface topography of the drumlins. Upper till layers exhibit unconformities on the flanks of the drumlins, except on their distal lee sides where layers were conformable. Till layers at approximately 2 m depth paralleled the drumlin surface and truncated lower layers. Below ca. 2 m depth distinct till layers dipped obliquely to the surface in the down-ice direction. These stratigraphic patterns were apparent in all drumlins measured at Múlajökull. The stratigraphic pattern observed in the drumlins of the Múlajökull forefield indicate a combination of deposition and erosion. Deposition occurred predominantly on the lee side and near the central axis of the drumlin, whereas erosion occurred along the flanks and stoss side. These observations support results from traditional litho-stratigraphic logs recorded on the same drumlins. Our observations suggest that drumlins migrated down ice and were initiated by a heterogeneous relief pattern in the drumlin forefield prior to the initial ice advance. This conceptual model supports observations that drumlins gained relief and became more elongated with time under the ice.

Validation of the FALL3D ash dispersion model using observations of the 2010 Eyjafjallajökull volcanic ash clouds

NASA Astrophysics Data System (ADS)

Folch, A.; Costa, A.; Basart, S.

2012-03-01

During April-May 2010 volcanic ash clouds from the Icelandic Eyjafjallajökull volcano reached Europe causing an unprecedented disruption of the EUR/NAT region airspace. Civil aviation authorities banned all flight operations because of the threat posed by volcanic ash to modern turbine aircraft. New quantitative airborne ash mass concentration thresholds, still under discussion, were adopted for discerning regions contaminated by ash. This has implications for ash dispersal models routinely used to forecast the evolution of ash clouds. In this new context, quantitative model validation and assessment of the accuracies of current state-of-the-art models is of paramount importance. The passage of volcanic ash clouds over central Europe, a territory hosting a dense network of meteorological and air quality observatories, generated a quantity of observations unusual for volcanic clouds. From the ground, the cloud was observed by aerosol lidars, lidar ceilometers, sun photometers, other remote-sensing instruments and in-situ collectors. From the air, sondes and multiple aircraft measurements also took extremely valuable in-situ and remote-sensing measurements. These measurements constitute an excellent database for model validation. Here we validate the FALL3D ash dispersal model by comparing model results with ground and airplane-based measurements obtained during the initial 14-23 April 2010 Eyjafjallajökull explosive phase. We run the model at high spatial resolution using as input hourly-averaged observed heights of the eruption column and the total grain size distribution reconstructed from field observations. Model results are then compared against remote ground-based and in-situ aircraft-based measurements, including lidar ceilometers from the German Meteorological Service, aerosol lidars and sun photometers from EARLINET and AERONET networks, and flight missions of the German DLR Falcon aircraft. We find good quantitative agreement, with an error similar to the spread in the observations (however depending on the method used to estimate mass eruption rate) for both airborne and ground mass concentration. Such verification results help us understand and constrain the accuracy and reliability of ash transport models and it is of enormous relevance for designing future operational mitigation strategies at Volcanic Ash Advisory Centers.

Long-term health of children following the Eyjafjallajökull volcanic eruption: a prospective cohort study.

PubMed

Hlodversdottir, Heidrun; Thorsteinsdottir, Harpa; Thordardottir, Edda Bjork; Njardvik, Urdur; Petursdottir, Gudrun; Hauksdottir, Arna

2018-01-01

Background : More than 500 million people worldwide live within exposure range of an active volcano and children are a vulnerable subgroup of such exposed populations. However, studies on the effects of volcanic eruptions on children's health beyond the first year are sparse. Objective : To examine the effect of the 2010 Eyjafjallajökull eruption on physical and mental health symptoms among exposed children in 2010 and 2013 and to identify potential predictive factors for symptoms. Method : In a population-based prospective cohort study, data was collected on the adult population ( N  = 1615) exposed to the 2010 Eyjafjallajökull eruption and a non-exposed group ( N  = 697). The exposed group was further divided according to exposure level. All participants answered questionnaires assessing their children´s and their own perceived health status in 2010 and 2013. Results : In 2010, exposed children were more likely than non-exposed children to experience respiratory symptoms (medium exposed OR 1.47; 95% CI 1.07-2.03; high exposed OR 1.52; 95% CI 1.03-2.24) and anxiety/worries (medium exposed OR 2.39; 95% CI 1.67-3.45; high exposed OR 2.77; 95% CI 1.81-4.27). Both genders had an increased risk of symptoms of anxiety/worries but only exposed boys were at increased risk of experiencing headaches and sleep disturbances compared to non-exposed boys. Within the exposed group, children whose homes were damaged were at increased risk of experiencing anxiety/worries (OR 1.62; 95% CI 1.13-2.32) and depressed mood (OR 1.55; 95% CI 1.07-2.24) than children whose homes were not damaged. Among exposed children, no significant decrease of symptoms was detected between 2010 and 2013. Conclusions : Adverse physical and mental health problems experienced by the children exposed to the eruption seem to persist for up to a three-year period post-disaster. These results underline the importance of appropriate follow-up for children after a natural disaster.

Continental crust beneath southeast Iceland.

PubMed

Torsvik, Trond H; Amundsen, Hans E F; Trønnes, Reidar G; Doubrovine, Pavel V; Gaina, Carmen; Kusznir, Nick J; Steinberger, Bernhard; Corfu, Fernando; Ashwal, Lewis D; Griffin, William L; Werner, Stephanie C; Jamtveit, Bjørn

2015-04-14

The magmatic activity (0-16 Ma) in Iceland is linked to a deep mantle plume that has been active for the past 62 My. Icelandic and northeast Atlantic basalts contain variable proportions of two enriched components, interpreted as recycled oceanic crust supplied by the plume, and subcontinental lithospheric mantle derived from the nearby continental margins. A restricted area in southeast Iceland--and especially the Öræfajökull volcano--is characterized by a unique enriched-mantle component (EM2-like) with elevated (87)Sr/(86)Sr and (207)Pb/(204)Pb. Here, we demonstrate through modeling of Sr-Nd-Pb abundances and isotope ratios that the primitive Öræfajökull melts could have assimilated 2-6% of underlying continental crust before differentiating to more evolved melts. From inversion of gravity anomaly data (crustal thickness), analysis of regional magnetic data, and plate reconstructions, we propose that continental crust beneath southeast Iceland is part of ∼350-km-long and 70-km-wide extension of the Jan Mayen Microcontinent (JMM). The extended JMM was marginal to East Greenland but detached in the Early Eocene (between 52 and 47 Mya); by the Oligocene (27 Mya), all parts of the JMM permanently became part of the Eurasian plate following a westward ridge jump in the direction of the Iceland plume.

Continental crust beneath southeast Iceland

PubMed Central

Torsvik, Trond H.; Amundsen, Hans E. F.; Trønnes, Reidar G.; Doubrovine, Pavel V.; Gaina, Carmen; Kusznir, Nick J.; Steinberger, Bernhard; Corfu, Fernando; Ashwal, Lewis D.; Griffin, William L.; Werner, Stephanie C.; Jamtveit, Bjørn

2015-01-01

The magmatic activity (0–16 Ma) in Iceland is linked to a deep mantle plume that has been active for the past 62 My. Icelandic and northeast Atlantic basalts contain variable proportions of two enriched components, interpreted as recycled oceanic crust supplied by the plume, and subcontinental lithospheric mantle derived from the nearby continental margins. A restricted area in southeast Iceland—and especially the Öræfajökull volcano—is characterized by a unique enriched-mantle component (EM2-like) with elevated 87Sr/86Sr and 207Pb/204Pb. Here, we demonstrate through modeling of Sr–Nd–Pb abundances and isotope ratios that the primitive Öræfajökull melts could have assimilated 2–6% of underlying continental crust before differentiating to more evolved melts. From inversion of gravity anomaly data (crustal thickness), analysis of regional magnetic data, and plate reconstructions, we propose that continental crust beneath southeast Iceland is part of ∼350-km-long and 70-km-wide extension of the Jan Mayen Microcontinent (JMM). The extended JMM was marginal to East Greenland but detached in the Early Eocene (between 52 and 47 Mya); by the Oligocene (27 Mya), all parts of the JMM permanently became part of the Eurasian plate following a westward ridge jump in the direction of the Iceland plume. PMID:25825769

The onset of an eruption: selective assimilation of hydrothermal minerals during pre-eruptive magma ascent of the 2010 summit eruption of Eyjafjallajökull volcano, Iceland

NASA Astrophysics Data System (ADS)

Pistolesi, M.; Cioni, R.; Francalanci, L.; Bertagnini, A.; D'Oriano, C.; Braschi, E.; Höskuldsson, A.

2016-11-01

The complex processes occurring in the initial phases of an eruption are often recorded in the products of its opening stage, which are usually characterized by small volume and limited dispersal, and thus generally poorly studied. The 2010 eruption of Eyjafjallajökull (Iceland) represents a unique opportunity for these investigations thanks to the good preservation of tephra deposits within the ice/snow pack. A detailed geochemical investigation on the glassy groundmass of single ash clasts disclosed a population of fragments with unusual high 87Sr/86Sr (up to 0.70668) for Icelandic magmatism, and anomalous elemental composition with respect to most of the juvenile material of the eruption. This suggests that during its rise, before intruding into the ice cover, magma at a dyke tip selectively assimilated hydrothermal minerals with seawater-related, high-Sr isotopic ratios (zeolites, silica phases, anhydrite) hosted in altered volcanic/epiclastic rocks. According to the observed precursory seismicity, only restricted to few hours before the onset of the eruption, this process could have accompanied subcritical aseismic fracture opening during the days before the eruption, possibly related to stress corrosion-cracking processes, which enhanced the partial dissolution/melting and subsequent selective assimilation of the host rocks.

A-Train Satellite Observations of Recent Explosive Eruptions in Iceland and Chile

NASA Astrophysics Data System (ADS)

Carn, S. A.; Yang, K.; Prata, A. J.

2012-04-01

The past few years have seen remarkable levels of explosive volcanic activity in Iceland and Chile, with four significant eruptions at Chaitén (May 2008), Eyjafjallajökull (April 2010), Grimsvötn (May 2011) and Cordón Caulle (June 2011 - ongoing). The tremendous disruption and economic impact of the Eyjafjallajökull eruption is well known, but each of these events had a significant impact on aviation, sometimes at great distances from the volcano. As of late 2011, volcanic ash from Cordón Caulle was still affecting airports in southern South America, highlighting the potential for extended disruption during long-lived eruptions. Serendipitously, this period of elevated volcanic activity has coincided with an era of unprecedented availability of satellite remote sensing data pertinent to volcanic cloud studies. In particular, NASA's A-Train satellite constellation (including the Aqua, CloudSat, CALIPSO, and Aura satellites) has been flying in formation since 2006, providing synergistic, multi- and hyper-spectral, passive and active observations. Measurements made by A-Train sensors include total column sulfur dioxide (SO2) by the Ozone Monitoring Instrument (OMI) on Aura, upper tropospheric and stratospheric (UTLS) SO2 column by the Atmospheric Infrared Sounder (AIRS) on Aqua and Microwave Limb Sounder (MLS) on Aura, ash mass loading from AIRS and the Moderate resolution Imaging Spectroradiometer (MODIS) on Aqua, UTLS HCl columns and ice water content (IWC) from MLS, aerosol vertical profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard CALIPSO, and hydrometeor profiles from the Cloud Profiling Radar (CPR) on CloudSat. The active vertical profiling capability of CALIPSO, CloudSat and MLS sychronized with synoptic passive sensing of trace gases and aerosols by OMI, AIRS and MODIS provides a unique perspective on the structure and composition of volcanic clouds. A-Train observations during the first hours of atmospheric residence are particularly valuable, as the fallout, segregation and stratification of material in this period determines the concentration and altitude of constituents that remain to be advected downwind. This represents the eruption 'source term' essential for ash dispersion modeling, and hence for aviation hazard mitigation. In this presentation we show how A-Train data have improved our understanding of the composition, structure and dynamics of volcanic eruption clouds, using examples from the recent Icelandic and Chilean eruptions. These events span a range of compositions and eruptive styles, including highly silicic, SO2-poor eruptions (Chaitén and Cordón Caulle), magma-ice interaction (Eyjafjallajökull and Grimsvötn), stratospheric eruption columns (Chaitén, Grimsvötn), and persistent, weak tropospheric plumes (Eyjafjallajökull). In each case, satellite remote sensing played a crucial role in characterizing the eruption, monitoring variations in intensity and tracking the dispersion of volcanic cloud constituents. We also describe plans for advanced SO2 and ash retrieval algorithms that will exploit the synergy between UV and IR sensors in the A-Train for improved quantification of ash and SO2 loading by volcanic eruptions.

Spain as an emergency air traffic hub during volcanic air fall events? Evidence of past volcanic ash air fall over Europe during the late Pleistocene

NASA Astrophysics Data System (ADS)

Hardiman, Mark; Lane, Christine; Blockley, Simon P. E.; Moreno, Ana; Valero-Garcés, Blas; Ortiz, José E.; Torres, Trino; Lowe, John J.; Menzies, Martin A.

2010-05-01

Past volcanic eruptions often leave visible ash layers in the geological record, for example in marine or lake sedimentary sequences. Recent developments, however, have shown that non-visible volcanic ash layers are also commonly preserved in sedimentary deposits. These augment the record of past volcanic events by demonstrating that past ash dispersals have been more numerous and widely disseminated in Europe than previously appreciated. The dispersal ‘footprints' of some large late Pleistocene European eruptions are examined here in the light of the recent Eyjafjallajökull eruption. For example, the Vedde Ash which was erupted from Iceland around 12 thousand years ago, delivered distal (and non-visible) glass deposits as far south as Switzerland and as far east as the Ural Mountains in Russia, with an overall European distribution remarkably similar to the dominant tracks of the recent Eyjafjallajökull plumes. The Eyjafjallajökull eruption has demonstrated that relatively small amounts of distal volcanic ash in the atmosphere can seriously disrupt aviation activity, with attendant economic and other consequences. It has raised fundamental questions about the likelihood of larger or more prolonged volcanic activity in the near future, and the possibility of even more serious consequences than those experienced recently. Given that there are several other volcanic centres that could cause such disruption in Europe (e.g. Campania and other volcanic centres in Italy; Aegean volcanoes), a key question is whether there are parts of Europe less prone to ash plumes and which could therefore operate as emergency air traffic hubs during times of ash dispersal. Although not generated to answer this question, the recent geological record might provide a basis for seeking the answer. For example, four palaeo-records covering the time frame of 8 - 40 Ka BP that are geographically distributed across Spain have been examined for non-visible distal ash content. All four have proved to be almost devoid of volcanic ash, which contrasts with results obtained from sites throughout central and northern Europe. This suggests that Spain has remained free of ashfall events throughout the late Pleistocene, or that any ash dispersal over Spain has been short-lived and/or infrequent. This appears to accord with the pattern of dispersal of Eyjafjallajökull ash clouds over April to May 2010. Most of the active period was characterised by low eruptive columns and the tropospheric dispersal of ash. Under these conditions, ash dispersal was multi-directional from eastern Europe to Greenland and beyond, but did not encroach on to the Iberian peninsula. In contrast, when the eruptive columns became more elevated and entrained in the jet stream, the dispersal directions were more uni-directional and passed over Iberia and North Africa. Thus the apparent lack of volcanic ash in Iberia (10 - 40ka) may have as much to do with eruptive column height and volcano location as with circulation patterns (tropospheric v. stratospheric). A more comprehensive assessment of geological records of non-visible ash layers in selected sites may hold the key to examining this matter more robustly.

Quantifying landscape change following the 1999 jökulhlaup at Sólheimajökull, southern Iceland

NASA Astrophysics Data System (ADS)

Staines, Kate E. H.

2010-05-01

Glacial outburst floods (jökulhlaups) occur periodically in glaciated areas worldwide as the result of subglacial volcanism, geothermal activity, natural dam-failures, high rainfall events and the release of stored meltwater. Despite their relative low frequency, the high discharge magnitudes and flow velocities can lead to widespread, intensive and long-lasting landscape change. Indeed, in the jökulhlaup-prone regions of southern Iceland, outburst floods are hypothesised to largely control long-term proglacial landscape evolution, with low-magnitude/high-frequency ablation-controlled meltwater flow having a minimal impact. Jökulhlaups also pose a major threat to populations, infrastructures and property. It is predicted with climate change that the frequency and potentially the magnitude of jökulhlaups will increase. It is therefore important to study jökulhlaup flow processes and understand how landscapes are impacted by and recover from these floods. Ultimately, this will better inform policy, flood prediction and hazard management in populated regions at risk from jökulhlaups. Currently, our understanding of jökulhlaup flow processes and the links between these processes and resulting landforms is limited. This is in parts due to the difficulty in directly measuring these high-magnitude, high-velocity floods. Research into jökulhlaup flow characteristics has consequently focussed on reconstructing flow parameters through a variety of palaeohydraulic techniques. However, these often produce conflicting and inaccurate reconstructions of flow inundation, peak discharge and flow rheology as key characteristics of jökulhlaups are frequently neglected (e.g. sediment transport, flow attenuation, sediment bulking and de-bulking). Furthermore, there has been little research into quantifying landscape change, response and recovery following jökulhlaups. The degree of preservation of flood deposits is determined in large parts by the pre-flood sensitivity of the landscape and its recovery potential. Factors controlling these include the recurrence interval and magnitude of past jökulhlaups, glacier surging, glacial advance and retreat cycles and fluctuations in glacier discharge. This study aims to quantify the immediate landscape change associated with a jökulhlaup and examine the response of the landscape in the years following the flood. The study site is the outwash plain (sandur) of Sólheimajökull, an outlet glacier of the Mýrdalsjökull ice cap in southern Iceland. The most recent jökulhlaup, triggered by the eruption of the subglacial volcano Katla, was in July 1999. Field surveys of a boulder fan deposited during the flood at the snout of Sólheimajökull will be used to reconstruct flow palaeocompetence, with cross-sections of the river channel used to calculate peak discharge. From orthorectified pre- and immediate post-flood aerial imagery, digital elevation models will be generated and used to quantify net elevation change (i.e. sediment loss or gain) across the flooded area. Geomorphological maps of the proglacial area from before and in the decade following the flood have been produced and will be used to quantify changes in the main river channel, in terms of braiding and sinuosity parameters.

Climatic implications of glacial evolution in the Tröllaskagi peninsula (northern Iceland) since the Little Ice Age maximum. The cases of the Gljúfurárjökull and Tungnahryggsjökull glaciers

NASA Astrophysics Data System (ADS)

Fernández-Fernández, José M.; Andrés, Nuria; Brynjólfsson, Skafti; Sæmundsson, Þorsteinn; Palacios, David

2017-04-01

The Tröllaskagi peninsula is located in northern Iceland, between meridians 19°30'W and 18°10'W, jutting out into the North Atlantic to latitude 66°12'N and joining the central highlands to the south. About 150 glaciers located on the Tröllaskagi peninsula reached their Holocene maximum extent during the Little Ice Age (LIA) maximum at the end of the 19th century. The sudden warming at the turn of the 20th century triggered a continuous retreat from the LIA maximum positions, interrupted by a reversal trend during the mid-seventies and eighties in response to a brief period of climate cooling. The aim of this paper is to analyze the relationships between glacial and climatic evolution since the LIA maximum. For this reason, we selected three small debris-free glaciers: Gljúfurárjökull, and western and eastern Tungnahryggsjökull, at the headwalls of Skíðadalur and Kolbeinsdalur, as their absence of debris cover makes them sensitive to climatic fluctuations. To achieve this purpose, we used ArcGIS to map the glacier extent during the LIA maximum and several dates over four georeferenced aerial photos (1946, 1985, 1994 and 2000), as well as a 2005 SPOT satellite image. Then, the Equilibrium-Line Altitude (ELA) was calculated by applying the Accumulation Area Ratio (AAR) and Area Altitude Balance Ratio (AABR) approaches. Climatological data series from the nearby weather stations were used in order to analyze climate development and to estimate precipitation at the ELA with different numerical models. Our results show considerable changes of the three debris-free glaciers and demonstrates their sensitivity to climatic fluctuations. As a result of the abrupt climatic transition of the 20th century, the following warm 25-year period and the warming started in the late eighties, the three glaciers retreated by ca. 990-1330 m from the LIA maximum to 2005, supported by a 40-metre ELA rise and a reduction of their area and volume of 25% and 33% on average, respectively. The 1.5 °C warming recorded at the city of Akureyri from late 19th century to 2005 does not agree with the 0.3 °C value obtained from the ELA rise and lapse rate. On the contrary it demonstrates that other factors - for example, precipitation and wind - have been decisive in the evolution of the glaciers. All the models applied suggest a precipitation increase of 700 mm water equivalent at the mean ELA since the LIA maximum, and higher and lower values depending on warm and cold periods respectively. The overall increase in precipitation is compatible with the increase in the surface temperature of the North Atlantic and a possible negative-to-positive shift in North Atlantic Oscillation (NAO) mode. However, the link between winter accumulation and prevailing wind directions recorded at nearby weather stations remains unclear. Research funded by Deglaciation project (CGL2015-65813-R), Government of Spain.

Using the 2010 Eyjafjallajökull eruption as an example of citizen involvement in scientific research

NASA Astrophysics Data System (ADS)

Klemetti, E. W.

2010-12-01

With the dramatic increase in realtime data for volcano monitoring (and many other earth science data) available on the internet, the interest in data analysis and observation by untrained citizens is increasing rapidly. These volcanologic data sources include, but are not limited to, seismic information, webicorders, webcams, GPS, water and gas fluxes. The easy access to these data has allowed not only for the public to see the raw data that volcanologists use to assess and predict activity of a volcanic system, but also to actively participate in the process of volcano monitoring. This can be manifested in activities such observation of the changes in volcanic behavior via webcams to manipulation of seismic data to analyze for changes in the character of the seismicity. However, the biggest challenge for citizen analysis and participation in volcano monitoring is providing guidance and structure for these data as they are presented on the internet. The 2010 eruption of Eyjafjallajökull in Iceland provided an opportunity to observe and develop a community of “citizen scientists” interested in volcano monitoring on the internet. The readers of the volcano blog Eruptions followed the pre-, during and post-eruptive activity at Eyjafjallajökull while providing observations and data interpretations as time-stamped comments. During the eruption, the blog was viewed over 1,000,000 times and over 3,000 comments were left by readers. Many of these comments contained: (1) detailed descriptions of the current activity of the volcano as observed on the webcams; (2) observations on changes in seismicity as seen in realtime data provided by the Icelandic Meteorological Office and (3); reader-created compilations of various data in the form of images, tables of movies. By moderating the blog comments and providing corrections and insight to their observations, the readers felt that they were participating in an important way to the monitoring and recording of this historic eruption. A sampling of the readers of the blog suggests that they represent a wide diversity of backgrounds, ranging from no college education to doctorates. A majority of readers held degrees in a science, however more than 60% had no to little formal geologic training. This suggests that there is a substantial desire for people to take part in geoscience research although they are not formally trained in the discipline. A parallel can be drawn between the use of realtime data and webcams during the Eyjafjallajökull eruption to the role of amateur astronomers in the observation and discovery of astronomical phenomena. However, this role for citizens is new in geosciences, where many times amateur enthusiasts are seen as merely "rock hounds" rather than potential sources of important scientific observation and information. By using geoscience blogging as a framework for drawing citizen participation in observation and interpretation of realtime data available on the internet, real contributions to the discipline can be made by non-specialists. However, trained geoscientists need to engage with the public to help guide and support their endeavors, monitoring for misuse of the data sets and provide the needed context to allow their contributions to be legitimate.

Volcanic-Ash Hazards to Aviation—Changes and Challenges since the 2010 Eruption of Eyjafjallajökull, Iceland

NASA Astrophysics Data System (ADS)

Guffanti, M.; Tupper, A.; Mastin, L. G.; Lechner, P.

2012-12-01

In response to the severe disruptions to civil aviation that resulted from atmospheric transport of ash from the eruption of Eyjafjallajökull volcano in Iceland in April and May 2010, the International Civil Aviation Organization (ICAO) quickly formed the International Volcanic Ash Task Force (IVATF), charging it to support the accelerated development of a global risk-management framework for volcanic-ash hazards to aviation. Recognizing the need for scientifically based advice on best methods to detect ash in the atmosphere and depict zones of hazardous airspace, the IVATF sought input from the global scientific community, primarily by means of the Volcanic Ash Scientific Advisory Group which was established in May 2010 by the World Meteorological Organization (WMO) and International Union of Geodesy and Geophysics to serve as a scientific resource for ICAO. The IVATF finished its work in June 2012 (see http://www.icao.int/safety/meteorology/ivatf/Pages/default.aspx for a record of its results). A major science-based outcome is that production of charts depicting areas of airspace expected to have specific ash-concentration values (e.g. <0.2, 0.2-2, 2-4, >4 mg/cu. m) will not be required of the world's nine Volcanic Ash Advisory Centers (VAACs). The VAACs are responsible for issuing warning information to the aviation sector regarding ash-cloud position and expected movement. Forecast concentrations in these charts are based primarily on dispersion models that have at least an order of magnitude in uncertainty in their output and therefore do not delineate hazardous airspace with the level of confidence needed by the aviation sector. The recommended approach to improving model-forecast accuracy is to assimilate diverse observations (e.g., satellite thermal-infrared measurements, lidar, radar, direct airborne sampling, visual sightings, etc.) into model simulations; doing that during an eruption in the demanding environment of aviation operations is a substantial challenge. A significant post-Eyjafjallajökull change has been renewed interest of the airline sector in the issue of ash hazards to aviation. Whereas it is accepted that flight into young, dense ash clouds is dangerous, many equipment manufacturers and airline operators view that dilute ash clouds (ash concentrations < ~2 mg/cu. m) can be transited without immediate safety impacts. This calls into question the long-standing mitigation strategy of complete ash avoidance. Consequently, entities under the ICAO and WMO banners, including the VAACs, are being challenged to provide more than qualitative "ash/no ash" depictions of affected airspace, while the aviation industry is being challenged to more fully specify what ash exposures cause economic as well as safety-related damage to aircraft. In the aftermath of the Eyjafjallajökull eruption, ICAO's global aviation-warning system of eruption reporting, ash cloud detecting and forecasting, and specialized messaging, implemented after highly damaging encounters of aircraft with ash clouds in the 1980's and 1990's, is still in place, but with renewed focus among all stakeholders on improving how hazardous airspace is defined and communicated.

Integrated Office Information System (IOIS) Summary Report. Automated Session Manager Analysis, Design and Implementation

DTIC Science & Technology

1990-05-01

1984, Keen and Scott Morton 1978, Richman 1987, Straub and Beauclair 19881. Previous research has shown the benefits of information technology in...been shown to foster collaboration, communication, deliberation, and negotiation [Apple et al 1986, Beauclair 1987, Easton 1988, Gray 1981, Kull 19821...Illinois. 7. Beauclair , R. A., 1987, "An Experimental Study of the Effects of GDSS Process Support Applica- tions on Small Group Decision Making

The Decline in America’s Reputation: Why

DTIC Science & Technology

2008-06-11

The Administration’s rhetoric about and unilateral military action against al- Qaeda and Saddam Hussein (and threats against Iran) have been...countries include Turkey, a long-standing U.S. ally, and Kuwait, the country that the United States liberated from Saddam Hussein’s rule as part of a...that it would not be bound by other nations’ opinions on the matter. According to Dr. Kull: [T]he complaint is not really that Saddam Hussein

An Exploratory Study of Ram Accelerator Principles

DTIC Science & Technology

1988-10-01

deeply indebted to their students, Carl Knowlen, Alan Kull, Ed Burnham, Kelley Ann Scott, Alfred Alvarez, Dai Murakami, Ivan Stonich, Dean Brackett, Dale...Conference, Honolulu, HI, June 8-10, 1987. 15. D.R. Stull and M. Prophet, project directors, JANAF Thermochemical Tables, U.S. Government Printing...Propulsion, Pergamon Press, New York, 1957. A-2. W.G. Vincenti and C.H. Kruger, Introduction to Physical Gas Dynamics, Wiley, New York, 1965. A-3. D.R. Stull

Long-term health effects of the Eyjafjallajökull volcanic eruption: a prospective cohort study in 2010 and 2013

PubMed Central

Hlodversdottir, Heidrun; Petursdottir, Gudrun; Gislason, Thorarinn; Hauksdottir, Arna

2016-01-01

Objectives To examine the long-term development of physical and mental health following exposure to a volcanic eruption. Design Population-based prospective cohort study. Setting In spring 2010, the Icelandic volcano Eyjafjallajökull erupted. Data were collected at 2 time points: in 2010 and 2013. Participants Adult residents in areas close to the Eyjafjallajökull volcano (N=1096), divided according to exposure levels, and a non-exposed sample (n=475), with 80% participation rate in 2013. Main outcome measures Physical symptoms in the previous year (chronic) and previous month (recent), and psychological distress (General Health Questionnaire-12-item version, GHQ-12), perceived stress (Perceived Stress Scale, PSS-4) and post traumatic stress disorder (PTSD) symptoms (Primary Care PTSD, PC-PTSD). Results In the exposed group, certain symptoms were higher in 2013 than in 2010, for example, morning phlegm during winter (OR 2.14; 95% CI 1.49 to 3.06), skin rash/eczema (OR 2.86; 95% CI 1.76 to 4.65), back pain (OR 1.45; 95% CI 1.03 to 2.05) and insomnia (OR 1.53; 95% CI 1.01 to 2.30), in addition to a higher prevalence of regular use of certain medications (eg, for asthma (OR 2.80; 95% CI 1.01 to 7.77)). PTSD symptoms decreased between 2010 and 2013 (OR 0.33; 95% CI 0.17 to 0.61), while the prevalence of psychological distress and perceived stress remained similar. In 2013, the exposed group showed a higher prevalence of various respiratory symptoms than did the non-exposed group, such as wheezing without a cold (high exposure OR 2.35; 95% CI 1.27 to 4.47) and phlegm (high exposure OR 2.81; 95% CI 1.48 to 5.55), some symptoms reflecting the degree of exposure (eg, nocturnal chest tightness (medium exposed OR 3.09; 95% CI 1.21 to 10.46; high exposed OR 3.42; 95% CI 1.30 to 11.79)). Conclusions The findings indicate that people exposed to a volcanic eruption, especially those most exposed, exhibit increased risk of certain symptoms 3–4 years after the eruption. PMID:27609845

Long-term health effects of the Eyjafjallajökull volcanic eruption: a prospective cohort study in 2010 and 2013.

PubMed

Hlodversdottir, Heidrun; Petursdottir, Gudrun; Carlsen, Hanne Krage; Gislason, Thorarinn; Hauksdottir, Arna

2016-09-08

To examine the long-term development of physical and mental health following exposure to a volcanic eruption. Population-based prospective cohort study. In spring 2010, the Icelandic volcano Eyjafjallajökull erupted. Data were collected at 2 time points: in 2010 and 2013. Adult residents in areas close to the Eyjafjallajökull volcano (N=1096), divided according to exposure levels, and a non-exposed sample (n=475), with 80% participation rate in 2013. Physical symptoms in the previous year (chronic) and previous month (recent), and psychological distress (General Health Questionnaire-12-item version, GHQ-12), perceived stress (Perceived Stress Scale, PSS-4) and post traumatic stress disorder (PTSD) symptoms (Primary Care PTSD, PC-PTSD). In the exposed group, certain symptoms were higher in 2013 than in 2010, for example, morning phlegm during winter (OR 2.14; 95% CI 1.49 to 3.06), skin rash/eczema (OR 2.86; 95% CI 1.76 to 4.65), back pain (OR 1.45; 95% CI 1.03 to 2.05) and insomnia (OR 1.53; 95% CI 1.01 to 2.30), in addition to a higher prevalence of regular use of certain medications (eg, for asthma (OR 2.80; 95% CI 1.01 to 7.77)). PTSD symptoms decreased between 2010 and 2013 (OR 0.33; 95% CI 0.17 to 0.61), while the prevalence of psychological distress and perceived stress remained similar. In 2013, the exposed group showed a higher prevalence of various respiratory symptoms than did the non-exposed group, such as wheezing without a cold (high exposure OR 2.35; 95% CI 1.27 to 4.47) and phlegm (high exposure OR 2.81; 95% CI 1.48 to 5.55), some symptoms reflecting the degree of exposure (eg, nocturnal chest tightness (medium exposed OR 3.09; 95% CI 1.21 to 10.46; high exposed OR 3.42; 95% CI 1.30 to 11.79)). The findings indicate that people exposed to a volcanic eruption, especially those most exposed, exhibit increased risk of certain symptoms 3-4 years after the eruption. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

The impact of the characteristics of volcanic ash on forecasting.

NASA Astrophysics Data System (ADS)

Beckett, Frances; Hort, Matthew; Millington, Sarah; Stevenson, John; Witham, Claire

2013-04-01

The eruption of Eyjafjallajökull during April - May 2010 and Grímsvötn in May 2011, Iceland, caused the widespread dispersion of volcanic ash across the NE Atlantic, and ultimately into UK and European airspace. This resulted in thousands of flights to and from affected countries across Europe to be cancelled. The Met Office, UK, is the home of the London VAAC, a Volcanic Ash Advisory Centre, and as such is responsible for providing reports and forecasts for the movement of volcanic ash clouds covering the UK, Iceland and the north-eastern part of the North Atlantic ocean. To forecast the dispersion of volcanic ash requires that the sedimentation of ash particles through the atmosphere is effectively modelled. The settling velocity of an ash particle is a function of its size, shape and density, plus the density and viscosity of the air through which it is falling. We consider the importance of characterising the physical properties of ash when modelling the long range dispersion of ash particles through the atmosphere. Using the Reynolds number dependent scheme employed by NAME, the Lagrangian particle model used operationally by the Met Office, we calculate the settling velocity and thus the maximum travel distance of an ash particle through an idealised atmosphere as a function of its size, shape and density. The results are compared to measured particle sizes from deposits across Europe following the eruption of Eyjafjallajökull in 2010. Further, the particle size distribution (PSD) of ash in a volcanic cloud with time is modelled using NAME: the particle density distribution and particle shape factor are varied and the modelled PSD compared to the PSD measured in the ash cloud during the eruption of Eyjafjallajökull in 2010 by the FAAM research aircraft. The influence of the weather on PSD is also considered by comparing model output using an idealised atmosphere to output using NWP driven meteorological fields. We discuss the sensitivity of forecasts of the dispersion of volcanic ash to the representation of particle characteristics in NAME, the importance of representing the weather in ash fall models, and the implications of these results for the operational forecasting of volcanic ash dispersion at the London VAAC.

Field Exploration and Life Detection Sampling for Planetary Analogue Research (FELDSPAR)

NASA Astrophysics Data System (ADS)

Gentry, D.; Stockton, A. M.; Amador, E. S.; Cable, M. L.; Cantrell, T.; Chaudry, N.; Cullen, T.; Duca, Z. A.; Jacobsen, M. B.; Kirby, J.; McCaig, H. C.; Murukesan, G.; Rennie, V.; Rader, E.; Schwieterman, E. W.; Stevens, A. H.; Sutton, S. A.; Tan, G.; Yin, C.; Cullen, D.; Geppert, W.

2017-12-01

Extraterrestrial studies are typically conducted on mg samples from cm-scale features, while landing sites are selected based on m to km-scale features. It is therefore critical to understand spatial distribution of organic molecules over scales from cm to the km, particularly in geological features that appear homogenous at m to km scales. This is addressed by FELDSPAR, a NASA-funded project that conducts field operations analogous to Mars sample return in its science, operations, and technology [1]. Here, we present recent findings from a 2016 and a 2017 campaign to multiple Martian analogue sites in Iceland. Icelandic volcanic regions are Mars analogues due to desiccation, low nutrient availability, temperature extremes [2], and are relatively young and isolated from anthropogenic contamination [3]. Operationally, many Icelandic analogue sites are remote enough to require that field expeditions address several sampling constraints that are also faced by robotic exploration [1, 2]. Four field sites were evaluated in this study. The Fimmvörðuháls lava field was formed by a basaltic effusive eruption associated with the 2010 Eyjafjallajökull eruption. Mælifellssandur is a recently deglaciated plain to the north of the Myrdalsjökull glacier. Holuhraun is a basaltic spatter and cinder cone formed by 2014 fissure eruptions just north of the Vatnajökull glacier. Dyngjusandur is a plain kept barren by repeated aeolian mechanical weathering. Samples were collected in nested triangular grids from 10 cm to the 1 km scale. We obtained overhead imagery at 1 m to 200 m elevation to create digital elevation models. In-field reflectance spectroscopy was obtained with an ASD spectrometer and chemical composition was measured by a Bruker handheld XRF. All sites chosen were homogeneous in apparent color, morphology, moisture, grain size, and reflectance spectra at all scales greater than 10 cm. Field lab ATP assays were conducted to monitor microbial habitation, and home laboratory analyses include qPCR, Raman spectroscopy and community sequencing. For more information, find us on Facebook @FELDSPAResearch. [1] Amador, E. S. et al. (2015) Planet. Space Sci., 106 1-10. [2] Cockell, C. S. et al., (2011) Astrobio., 11 679-694; Gentry, et al., (2017) Astrobio., in press. [3] Bagshaw, E. A. et al., (2011) Astrobio., 11 651-664.

Unstructured Polyhedral Mesh Thermal Radiation Diffusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmer, T.S.; Zika, M.R.; Madsen, N.K.

2000-07-27

Unstructured mesh particle transport and diffusion methods are gaining wider acceptance as mesh generation, scientific visualization and linear solvers improve. This paper describes an algorithm that is currently being used in the KULL code at Lawrence Livermore National Laboratory to solve the radiative transfer equations. The algorithm employs a point-centered diffusion discretization on arbitrary polyhedral meshes in 3D. We present the results of a few test problems to illustrate the capabilities of the radiation diffusion module.

Iceland

NASA Image and Video Library

2015-03-09

Iceland, dressed in winter white, peaked through a hole in a complex system of clouds in late February, 2015. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured this true-color image on February 21 as it passed over the region. Ice and snow covers Iceland almost entirely, except for coastal regions in the southwest and southeast. The extensive, roughly H-shaped area in the southeast section of the island is Vatnajökull, Iceland’s largest glacier. Hidden underneath the ice lies Bardarbunga, a large subglacial stratovolcano. On August 31, 2014 the volcano began an eruption at two fissures to the north of the glacier and deposited a lava field that measured about 131 feet (40 meters) at its thickest points, and covered an area about 33 sq. mi (85 sq. km) by the time the eruption ended on February 27, 2015. The massive lava flow left its mark on Iceland – the cooled lava can be seen as the roughly oval black area to the north of the Vatnajökull glacier. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Geophysical Tracking of a Subglacial Flood in Near Real-Time

NASA Astrophysics Data System (ADS)

Eibl, Eva P. S.; Jóhannesson, Tómas; Ofeigsson, Benedikt G.; Roberts, Matthew J.; Bean, Christopher J.; Vogfjörd, Kristin S.; Jones, Morgan T.; Pfeffer, Melissa A.; Bergsson, Baldur; Pálsson, Finnur

2017-04-01

Subglacial lakes and volcanoes in Iceland pose a risk to people, livestock and infrastructure when water drains in subglacial floods. Many of these floods occur every year and efforts are made to forecast them and evacuate in time. The two Skaftá cauldrons are located at the southwestern part of Vatnajökull glacier and usually drain once every two years. However, following drainage in 2010, the eastern cauldron did not drain before October 2015. While water accumulated over these five years, scientists - within the EU-funded project FutureVolc - improved the monitoring network around southwest Vatnajökull in order to record the flood in great detail. The network finally comprised two seismic arrays, a GPS instrument on top of the cauldron, two GPS instruments above the flood path, gas measurements at the glaciers' edge, hydrological measurements at river gauges and osmotic sampler data. We present how the GPS, gas and hydrological instruments allow us to detect the start of and subglacial propagation of the flood. The derived timing is consistent with the approximate time of rupturing of the ice close to the glacier edge and the source movement observed in the seismic signals. The subglacial flow of water is accompanied by seismic tremor, whose source location moves downslope with the flood front. This tremor is followed by about 24 hours of stronger tremor bursts from the direction of the empty cauldron.

In-situ observations of Eyjafjallajökull ash particles by hot-air balloon

NASA Astrophysics Data System (ADS)

Petäjä, T.; Laakso, L.; Grönholm, T.; Launiainen, S.; Evele-Peltoniemi, I.; Virkkula, A.; Leskinen, A.; Backman, J.; Manninen, H. E.; Sipilä, M.; Haapanala, S.; Hämeri, K.; Vanhala, E.; Tuomi, T.; Paatero, J.; Aurela, M.; Hakola, H.; Makkonen, U.; Hellén, H.; Hillamo, R.; Vira, J.; Prank, M.; Sofiev, M.; Siitari-Kauppi, M.; Laaksonen, A.; lehtinen, K. E. J.; Kulmala, M.; Viisanen, Y.; Kerminen, V.-M.

2012-03-01

The volcanic ash cloud from Eyjafjallajökull volcanic eruption seriously distracted aviation in Europe. Due to the flight ban, there were only few in-situ measurements of the properties and dispersion of the ash cloud. In this study we show in-situ observations onboard a hot air balloon conducted in Central Finland together with regional dispersion modelling with SILAM-model during the eruption. The modeled and measured mass concentrations were in a qualitative agreement but the exact elevation of the layer was slightly distorted. Some of this discrepancy can be attributed to the uncertainty in the initial emission height and strength. The observed maximum mass concentration varied between 12 and 18 μg m -3 assuming a density of 2 g m -3, whereas the gravimetric analysis of the integrated column showed a maximum of 45 μg m -3 during the first two descents through the ash plume. Ion chromatography data indicated that a large fraction of the mass was insoluble to water, which is in qualitative agreement with single particle X-ray analysis. A majority of the super-micron particles contained Si, Al, Fe, K, Na, Ca, Ti, S, Zn and Cr, which are indicative for basalt-type rock material. The number concentration profiles indicated that there was secondary production of particles possibly from volcano-emitted sulfur dioxide oxidized to sulfuric acid during the transport.

EARLINET observations of the Eyjafjallajökull ash plume over Europe

NASA Astrophysics Data System (ADS)

Pappalardo, Gelsomina; Amodeo, Aldo; Ansmann, Albert; Apituley, Arnoud; Alados Arboledas, Lucas; Balis, Dimitris; Böckmann, Christine; Chaikovsky, Anatoli; Comeron, Adolfo; D'Amico, Giuseppe; De Tomasi, Ferdinando; Freudenthaler, Volker; Giannakaki, Elina; Giunta, Aldo; Grigorov, Ivan; Gustafsson, Ove; Gross, Silke; Haeffelin, Martial; Iarlori, Marco; Kinne, Stefan; Linné, Holger; Madonna, Fabio; Mamouri, Rodanthi; Mattis, Ina; McAuliffe, Michael; Molero, Francisco; Mona, Lucia; Müller, Detlef; Mitev, Valentin; Nicolae, Doina; Papayannis, Alexandros; Perrone, Maria Rita; Pietruczuk, Aleksander; Pujadas, Manuel; Putaud, Jean-Philippe; Ravetta, Francois; Rizi, Vincenzo; Serikov, Ilya; Sicard, Michael; Simeonov, Valentin; Spinelli, Nicola; Stebel, Kerstin; Trickl, Thomas; Wandinger, Ulla; Wang, Xuan; Wagner, Frank; Wiegner, Matthias

2010-10-01

EARLINET, the European Aerosol Research Lidar NETwork, established in 2000, is the first coordinated lidar network for tropospheric aerosol study on the continental scale. The network activity is based on scheduled measurements, a rigorous quality assurance program addressing both instruments and evaluation algorithms, and a standardised data exchange format. At present, the network includes 27 lidar stations distributed over Europe. EARLINET performed almost continuous measurements since 15 April 2010 in order to follow the evolution of the volcanic plume generated from the eruption of the Eyjafjallajökull volcano, providing the 4-dimensional distribution of the volcanic ash plume over Europe. During the 15-30 April period, volcanic particles were detected over Central Europe over a wide range of altitudes, from 10 km down to the local planetary boundary layer (PBL). Until 19 April, the volcanic plume transport toward South Europe was nearly completely blocked by the Alps. After 19 April volcanic particles were transported to the south and the southeast of Europe. Descending aerosol layers were typically observed all over Europe and intrusion of particles into the PBL was observed at almost each lidar site that was affected by the volcanic plume. A second event was observed over Portugal and Spain (6 May) and then over Italy on 9 May 2010. The volcanic plume was then observed again over Southern Germany on 11 May 2010.

Evaluation of remote-sensing techniques to measure decadal-scale changes of Hofsjokull ice cap, Iceland

USGS Publications Warehouse

Hall, D.K.; Williams, R.S.; Barton, J.S.; Sigurdsson, O.; Smith, L.C.; Garvin, J.B.

2000-01-01

Dynamic surficial changes and changes in the position of the firn line and the areal extent of Hofsjökull ice cap, Iceland, were studied through analysis of a time series (1973–98) of synthetic-aperture radar (SAR) and Landsat data. A digital elevation model of Hofsjökull, which was constructed using SAR interferometry, was used to plot the SAR backscatter coefficient (σ°) vs elevation and air temperature along transects across the ice cap. Seasonal and daily σ° patterns are caused by freezing or thawing of the ice-cap surface, and abrupt changes in σ° are noted when the air temperature ranges from ∼−5° to 0°C. Late-summer 1997 σ° (SAR) and reflectance (Landsat) boundaries agree and appear to be coincident with the firn line and a SAR σ° boundary that can be seen in the January 1998 SAR image. In January 1994 through 1998, the elevation of this σ° boundary on the ice capwas quite stable, ranging from 1000 to 1300 m, while the equilibrium-line altitude, as measured on the ground, varied considerably. Thus the equilibrium line may be obscured by firn from previous years. Techniques are established to measure long-term changes in the elevation of the firn line and changes in the position of the ice margin.

Chemistry and fluxes of magmatic gases powering the explosive trachyandesitic phase of Eyjafjallajokull 2010 eruption: constraints on degassing magma volumes and processes

NASA Astrophysics Data System (ADS)

Allard, P.; Burton, M. R.; Oskarsson, N.; Michel, A.; Polacci, M.

2010-12-01

The 2010 Eyjafjallajökull eruption developed in two distinct phases, with initial lateral effusion of alkali basalt since March 20, followed by highly explosive extrusion of a quite homogenous and crystal-poor trachyandesitic magma [1] through the central volcano ice cap between April 14 and May 24. As usual, magmatic volatiles played a key role in the eruption dynamics. Here we report on the chemical composition and the mass output of magmatic gases powering intense explosive activity during the second eruptive phase in early May. On May 8 we could measure the composition of magmatic gases directly issuing from the eruptive vents, by using OP-FTIR spectroscopy from the crater rim (~900 m distance) and molten lava blocks as IR radiation source. FTIR spectra reveal a variable mixture between two gas components equally rich in H2O (91.3 mol%) and CO2 (8%) but differing in their SO2/HCl ratio (up to 3.5 for the main one and 0.5 for the Cl-richer second one). Analysis of S-Cl-F in ash leachates and in ash and lava bomb samples (pyrohydrolysis) show that this second component was generated by greater chlorine loss during extensive magma fragmentation into fine ash. S/Cl and Cl/F ratios from both these analyses and solar occultation FTIR plume sensing indicate a modest fluorine content in emitted gas and its preferential adsorption onto solid particles during plume transport. DOAS traverses under the volcanic plume (4-6 km height), though hampered by dense ash load, gave most reliable SO2 fluxes of 4500-6600 tons d-1 on May 9, consistent with OMI satellite data [2]. These imply the daily co-emission of 7.2x105 tons of H2O, 1.5x105 tons of CO2, 2000 tons of HCl and ≤200 tons of HF. Eyjafjallajökull thus produced more hydrous and relatively CO2-poorer gas, in much greater quantities, during that stage than during its first basaltic phase [3]. Linear variations of dissolved S with TiO2/FeO ratio in nearby Katla alkali magmas [4] suggest possible pre-eruptive S contents of 0.17-0.19 and 0.14-0.16 wt% in Eyjafjallajökull alkali basalt and trachyandesite, respectively. With 0.03 wt% of residual S measured in erupted lavas, we compute the degassing of ~106 m3 d-1 of trachyandesite in early May, compared to only ~3.5x105 m3 d-1 of basalt in early April. The alkali basalt was petrologically equilibrated at ≤2 kbar and 1150°C [1] but, given the CO2/S ratio of basaltic gases from the first phase [3], might have initially contained ≥1 wt% of carbon dioxide at greater depth. Early CO2 exsolution from this uprising basalt and its interaction with more evolved magma in a shallower reservoir beneath Eyjafjallajökull could have generated enough overpressure for triggering the eruption. [1] N. Oskarsson, 2010, http://www.earthice.hi.is/; [2] P. Labazuy et al., OPGC-LMV, Clermont-Ferrand, France, April 2010, http://wwwobs.univ-bpclermont.fr/; [3] Burton et al., Gas composition and flux report, March 2010, http://www.earthice.hi.is/; [4] Thordarson et al., In: Volcanic Degassing, Geol. Soc. London, special public. 213, 2006.

Discovery of the Largest Historic Silicic Submarine Eruption

NASA Astrophysics Data System (ADS)

Carey, Rebecca J.; Wysoczanski, Richard; Wunderman, Richard; Jutzeler, Martin

2014-05-01

It was likely twice the size of the renowned Mount St. Helens eruption of 1980 and perhaps more than 10 times bigger than the more recent 2010 Eyjafjallajökull eruption in Iceland. However, unlike those two events, which dominated world news headlines, in 2012 the daylong submarine silicic eruption at Havre volcano in the Kermadec Arc, New Zealand (Figure 1a; ~800 kilometers north of Auckland, New Zealand), passed without fanfare. In fact, for a while no one even knew it had occurred.

Identification and characterization of individual airborne volcanic ash particles by Raman microspectroscopy.

PubMed

Ivleva, Natalia P; Huckele, Susanne; Weinzierl, Bernadett; Niessner, Reinhard; Haisch, Christoph; Baumann, Thomas

2013-11-01

We present for the first time the Raman microspectroscopic identification and characterization of individual airborne volcanic ash (VA) particles. The particles were collected in April/May 2010 during research aircraft flights, which were performed by Deutsches Zentrum für Luft- und Raumfahrt in the airspace near the Eyjafjallajökull volcano eruption and over Europe (between Iceland and Southern Germany). In addition, aerosol particles were sampled by an Electrical Low Pressure Impactor in Munich, Germany. As references for the Raman analysis, we used the spectra of VA collected at the ground near the place of eruption, of mineral basaltic rock, and of different minerals from a database. We found significant differences in the spectra of VA and other aerosol particles (e.g., soot, nitrates, sulfates, and clay minerals), which allowed us to identify VA among other atmospheric particulate matter. Furthermore, while the airborne VA shows a characteristic Raman pattern (with broad band from ca. 200 to ca. 700 cm(-1) typical for SiO₂ glasses and additional bands of ferric minerals), the differences between the spectra of aged and fresh particles were observed, suggesting differences in their chemical composition and/or structure. We also analyzed similarities between Eyjafjallajökull VA particles collected at different sampling sites and compared the particles with a large variety of glassy and crystalline minerals. This was done by applying cluster analysis, in order to get information on the composition and structure of volcanic ash.

Eyjafjallajökull and 9/11: The Impact of Large-Scale Disasters on Worldwide Mobility

PubMed Central

Woolley-Meza, Olivia; Grady, Daniel; Thiemann, Christian; Bagrow, James P.; Brockmann, Dirk

2013-01-01

Large-scale disasters that interfere with globalized socio-technical infrastructure, such as mobility and transportation networks, trigger high socio-economic costs. Although the origin of such events is often geographically confined, their impact reverberates through entire networks in ways that are poorly understood, difficult to assess, and even more difficult to predict. We investigate how the eruption of volcano Eyjafjallajökull, the September 11th terrorist attacks, and geographical disruptions in general interfere with worldwide mobility. To do this we track changes in effective distance in the worldwide air transportation network from the perspective of individual airports. We find that universal features exist across these events: airport susceptibilities to regional disruptions follow similar, strongly heterogeneous distributions that lack a scale. On the other hand, airports are more uniformly susceptible to attacks that target the most important hubs in the network, exhibiting a well-defined scale. The statistical behavior of susceptibility can be characterized by a single scaling exponent. Using scaling arguments that capture the interplay between individual airport characteristics and the structural properties of routes we can recover the exponent for all types of disruption. We find that the same mechanisms responsible for efficient passenger flow may also keep the system in a vulnerable state. Our approach can be applied to understand the impact of large, correlated disruptions in financial systems, ecosystems and other systems with a complex interaction structure between heterogeneous components. PMID:23950904

Intrusion Triggering of Explosive Eruptions: Lessons Learned from EYJAFJALLAJÖKULL 2010 Eruptions and Crustal Deformation Studies

NASA Astrophysics Data System (ADS)

Sigmundsson, F.; Hreinsdottir, S.; Hooper, A. J.; Arnadottir, T.; Pedersen, R.; Roberts, M. J.; Oskarsson, N.; Auriac, A.; Decriem, J.; Einarsson, P.; Geirsson, H.; Hensch, M.; Ofeigsson, B. G.; Sturkell, E. C.; Sveinbjornsson, H.; Feigl, K.

2010-12-01

Gradual inflation of magma chambers often precedes eruptions at highly active volcanoes. During eruptions, rapid deflation occurs as magma flows out and pressure is reduced. Less is known about the deformation style at moderately active volcanoes, such as Eyjafjallajökull, Iceland, where an explosive summit eruption of trachyandesite beginning on 14 April 2010 caused exceptional disruption to air traffic. This eruption was preceded by an effusive flank eruption of olivine basalt from 20 March - 12 April 2010. Geodetic and seismic observations revealed the growth of an intrusive complex in the roots of the volcano during three months prior to eruptions. After initial horizontal growth, modelling indicates both horizontal and sub-vertical growth in three weeks prior the first eruption. The behaviour is attributed to subsurface variations in crustal stress and strength originating from complicated volcano foundations. A low-density layer may capture magma allowing pressure to build before an intrusion can ascend towards higher levels. The intrusive complex was formed by olivine basalt as erupted on the volcano flank 20 March - 12 April; the intrusive growth halted at the onset of this eruption. Deformation associated with the eruption onset was minor as the dike had reached close to the surface in the days before. Isolated eruptive vents opening on long-dormant volcanoes may represent magma leaking upwards from extensive pre-eruptive intrusions formed at depth. A deflation source activated during the summit eruption of trachyandesite is distinct from, and adjacent to, all documented sources of inflation in the volcano roots. Olivine basalt magma which recharged the volcano appears to have triggered the summit eruption, although the exact mode of triggering is uncertain. Scenarios include stress triggering or propagation of olivine basalt into more evolved magma. The trachyandesite includes crystals that can be remnants of minor recent intrusion of olivine basalt. Alternatively, mixing of larger portion of olivine basalt with more evolved magma may have occurred. Intrusions may lead to eruptions not only when they find their way to the surface; at Eyjafjallajökull our observation show how primitive melts in an intrusive complex active since 1992 catalyzed an explosive eruption of trachyandesite. Eyjafjallajökull’s behaviour can be attributed to its off-rift setting with a relatively cold subsurface structure and limited magma at shallow depth, as may be typical for moderately active volcanoes. Clear signs of volcanic unrest signals over years to weeks may indicate reawakening of such volcanoes whereas immediate short-term precursors may be subtle and difficult to detect.

Iceland Volcano Puffs Ash as Lava Flow Cuts Through Eyjafjallajökull Icecap

NASA Image and Video Library

2010-05-05

Dramatic changes have been observed at the Eyjafjallajökull volcano in Iceland by NASA's Earth Observing 1 (EO-1) spacecraft. On May 2, 2010, the Hyperion hyperspectral imager on EO-1 imaged Eyjafjallajökull and identified the extent of a lava flow extending northwards from the main eruption vent. This lava flow had been previously reported by volcanologists in Iceland, and is slowly carving its way north through the ice cap. The image on the left (Figure 1) is at visible wavelengths, and shows the persistent dark volcanic plume emanating from the main vent. This plume is still rich in ash, hence its brown coloration. This ash is still causing problems, threatening new airspace closures over parts of Europe. Large cracks at the edge of the crater are an indication of the extent of ice removal from the icecap during the eruption. To the north of this vent is another plume that is very white. This second plume is the result of ice being boiled off, generally non-explosively, by the heat from the silicate lava flow. As a result this plume is probably comprised mostly of water vapour. The black lava shows up clearly against the ice in the left-hand image. The image in the center (Figure 2) is a false-color image in the short-wavelength infrared. In this image, ice appears as blue and hot pixels appear as red. Very hot pixels appear as yellow and white. Red pixels, visible though the plume chart the extent of the lava flow, which has extended some 1.8 kilometers (1.1 miles) northwards from the area of the vent that is emitting the most energy. Total heat loss on May 2 was estimated to be at least 300 megawatts. The image on the right (Figure 3) shows the lava flow on May 4, 2010. The entire lava channel is now exposed, most of the overlying ice having been removed and the white plume has mostly disappeared. Without the plume obscuring heat loss from the lava flow, a better estimate of heat loss can be made. On May 4, the volcano was emitting at least 1,600 megawatts of energy. Each image covers an area measuring 7.7 kilometers (4.8 miles) wide, and has a resolution of 30 meters (98 feet) per pixel. The vertical direction is north-northeast. http://photojournal.jpl.nasa.gov/catalog/PIA13098

vanC Cluster of Vancomycin-Resistant Enterococcus gallinarum BM4174

PubMed Central

Arias, Cesar A.; Courvalin, Patrice; Reynolds, Peter E.

2000-01-01

Glycopeptide-resistant enterococci of the VanC type synthesize UDP-muramyl-pentapeptide[d-Ser] for cell wall assembly and prevent synthesis of peptidoglycan precursors ending in d-Ala. The vanC cluster of Enterococcus gallinarum BM4174 consists of five genes: vanC-1, vanXYC, vanT, vanRC, and vanSC. Three genes are sufficient for resistance: vanC-1 encodes a ligase that synthesizes the dipeptide d-Ala-d-Ser for addition to UDP-MurNAc-tripeptide, vanXYC encodes a d,d-dipeptidase–carboxypeptidase that hydrolyzes d-Ala-d-Ala and removes d-Ala from UDP-MurNAc-pentapeptide[d-Ala], and vanT encodes a membrane-bound serine racemase that provides d-Ser for the synthetic pathway. The three genes are clustered: the start codons of vanXYC and vanT overlap the termination codons of vanC-1 and vanXYC, respectively. Two genes which encode proteins with homology to the VanS-VanR two-component regulatory system were present downstream from the resistance genes. The predicted amino acid sequence of VanRC exhibited 50% identity to VanR and 33% identity to VanRB. VanSC had 40% identity to VanS over a region of 308 amino acids and 24% identity to VanSB over a region of 285 amino acids. All residues with important functions in response regulators and histidine kinases were conserved in VanRC and VanSC, respectively. Induction experiments based on the determination of d,d-carboxypeptidase activity in cytoplasmic extracts confirmed that the genes were expressed constitutively. Using a promoter-probing vector, regions upstream from the resistance and regulatory genes were identified that have promoter activity. PMID:10817725

Subglacial volcanic activity above a lateral dyke path during the 2014-2015 Bárdarbunga-Holuhraun rifting episode, Iceland

NASA Astrophysics Data System (ADS)

Reynolds, Hannah I.; Gudmundsson, Magnús T.; Högnadóttir, Thórdís; Magnússon, Eyjólfur; Pálsson, Finnur

2017-06-01

The rifting episode associated with the Bárdarbunga-Holuhraun eruption in 2014-2015 included the first observations of major dyke propagation under ice. Three shallow ice depressions (ice cauldrons) with volumes ranging from 1 to 18 million m3 formed in Dyngjujökull glacier above the 48-km-long lateral path of the magma, at 4, 7 and 12 km from the northern glacier edge. Aircraft-based radar altimetry profiling was used to map the evolution of the cauldrons and construct a time series of the heat transfer rates. Out of the three scenarios explored: (1) onset or increase of hydrothermal activity, (2) convection within vertical fissures filled with water overlying intruded magma and (3) subglacial eruptions, the last option emerges as the only plausible mechanism to explain the rapid heat transfer observed in a location far from known geothermal areas. The thermal signals at two of the cauldrons are consistent with effusive subglacial eruptions. The formation of the northernmost cauldron was more rapid, indicating faster heat transfer rates. Radio-echo sounding data indicate that in contrast to the other two cauldrons, an intrusion of eruptive products occurred into the glacier, reaching 50-60 m above bedrock with the increased magma-ice contact explaining the more rapid heat transfer. We propose that the 2-m widening associated with graben formation increased the groundwater storage capacity of the bedrock, creating space for the meltwater to be stored, explaining the absence of meltwater pulses draining from Dyngjujökull.

A Theoretical Model of Drumlin Formation Based on Observations at Múlajökull, Iceland

NASA Astrophysics Data System (ADS)

Iverson, N. R.; McCracken, R. G.; Zoet, L. K.; Benediktsson, Í. Ö.; Schomacker, A.; Johnson, M. D.; Woodard, J.

2017-12-01

The drumlin field at the surge-type glacier, Múlajökull, provides an unusual opportunity to build a model of drumlin formation based on field observations in a modern drumlin-forming environment. These observations indicate that surges deposit till layers that drape the glacier forefield, conform to drumlin surfaces, and are deposited in shear. Observations also indicate that erosion helps create drumlin relief, effective stresses in subglacial till are highest between drumlins, and during quiescent flow, crevasses on the glacier surface overlie drumlins while subglacial channels occupy intervening swales. In the model, we consider gentle undulations on the bed bounded by subglacial channels at low water pressure. During quiescent flow, slip of temperate ice across these undulations and basal water flow toward bounding channels create an effective stress distribution that maximizes till entrainment in ice on the heads and flanks of drumlins. Crevasses amplify this effect but are not necessary for it. During surges, effective stresses are uniformly low, and the bed shears pervasively. Vigorous basal melting during surges releases debris from ice and deposits it on the bed, with deposition augmented by transport in the deforming bed. As surge cycles progress, drumlins migrate downglacier and grow at increasing rates, due to positive feedbacks that depend on drumlin height. Drumlin growth can be accompanied by either net aggradation or erosion of the bed, and drumlin heights and stratigraphy generally correspond with observations. This model highlights that drumlin growth can reflect instabilities other than those of bed shear instability models, which require heuristic till transport assumptions.

Characterization of Eyjafjallajökull volcanic ash particles and a protocol for rapid risk assessment

PubMed Central

Gislason, S. R.; Hassenkam, T.; Nedel, S.; Bovet, N.; Eiriksdottir, E. S.; Alfredsson, H. A.; Hem, C. P.; Balogh, Z. I.; Dideriksen, K.; Oskarsson, N.; Sigfusson, B.; Larsen, G.; Stipp, S. L. S.

2011-01-01

On April 14, 2010, when meltwaters from the Eyjafjallajökull glacier mixed with hot magma, an explosive eruption sent unusually fine-grained ash into the jet stream. It quickly dispersed over Europe. Previous airplane encounters with ash resulted in sandblasted windows and particles melted inside jet engines, causing them to fail. Therefore, air traffic was grounded for several days. Concerns also arose about health risks from fallout, because ash can transport acids as well as toxic compounds, such as fluoride, aluminum, and arsenic. Studies on ash are usually made on material collected far from the source, where it could have mixed with other atmospheric particles, or after exposure to water as rain or fog, which would alter surface composition. For this study, a unique set of dry ash samples was collected immediately after the explosive event and compared with fresh ash from a later, more typical eruption. Using nanotechniques, custom-designed for studying natural materials, we explored the physical and chemical nature of the ash to determine if fears about health and safety were justified and we developed a protocol that will serve for assessing risks during a future event. On single particles, we identified the composition of nanometer scale salt coatings and measured the mass of adsorbed salts with picogram resolution. The particles of explosive ash that reached Europe in the jet stream were especially sharp and abrasive over their entire size range, from submillimeter to tens of nanometers. Edges remained sharp even after a couple of weeks of abrasion in stirred water suspensions. PMID:21518890

Genetics Home Reference: achromatopsia

MedlinePlus

... NW, Roosing S, van Schooneveld MJ, van Lith-Verhoeven JJ, van Moll-Ramirez N, van den Born LI, ... van Schooneveld MJ, Strom TM, van Lith-Verhoeven JJ, Lotery AJ, van Moll-Ramirez N, Leroy BP, ...

Glycopeptide Resistance vanA Operons in Paenibacillus Strains Isolated from Soil

PubMed Central

Guardabassi, Luca; Perichon, Bruno; van Heijenoort, Jean; Blanot, Didier; Courvalin, Patrice

2005-01-01

The sequence and gene organization of the van operons in vancomycin (MIC of >256 μg/ml)- and teicoplanin (MIC of ≥32 μg/ml)-resistant Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B isolated from soil were determined. Both operons had regulatory (vanR and vanS), resistance (vanH, vanA, and vanX), and accessory (vanY, vanZ, and vanW) genes homologous to the corresponding genes in enterococcal vanA and vanB operons. The vanAPT operon in P. thiaminolyticus PT-2B1 had the same gene organization as that of vanA operons whereas vanAPA in P. apiarius PA-B2B resembled vanB operons due to the presence of vanW upstream from the vanHAX cluster but was closer to vanA operons in sequence. Reference P. apiarius strains NRRL B-4299 and NRRL B-4188 were found to harbor operons indistinguishable from vanAPA by PCR mapping, restriction fragment length polymorphism, and partial sequencing, suggesting that this operon was species specific. As in enterococci, resistance was inducible by glycopeptides and associated with the synthesis of pentadepsipeptide peptidoglycan precursors ending in d-Ala-d-Lac, as demonstrated by d,d-dipeptidase activities, high-pressure liquid chromatography, and mass spectrometry. The precursors differed from those in enterococci by the presence of diaminopimelic acid instead of lysine in the peptide chain. Altogether, the results are compatible with the notion that van operons in soil Paenibacillus strains and in enterococci have evolved from a common ancestor. PMID:16189102

Glycopeptide resistance vanA operons in Paenibacillus strains isolated from soil.

PubMed

Guardabassi, Luca; Perichon, Bruno; van Heijenoort, Jean; Blanot, Didier; Courvalin, Patrice

2005-10-01

The sequence and gene organization of the van operons in vancomycin (MIC of >256 microg/ml)- and teicoplanin (MIC of > or =32 microg/ml)-resistant Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B isolated from soil were determined. Both operons had regulatory (vanR and vanS), resistance (vanH, vanA, and vanX), and accessory (vanY, vanZ, and vanW) genes homologous to the corresponding genes in enterococcal vanA and vanB operons. The vanA(PT) operon in P. thiaminolyticus PT-2B1 had the same gene organization as that of vanA operons whereas vanA(PA) in P. apiarius PA-B2B resembled vanB operons due to the presence of vanW upstream from the vanHAX cluster but was closer to vanA operons in sequence. Reference P. apiarius strains NRRL B-4299 and NRRL B-4188 were found to harbor operons indistinguishable from vanA(PA) by PCR mapping, restriction fragment length polymorphism, and partial sequencing, suggesting that this operon was species specific. As in enterococci, resistance was inducible by glycopeptides and associated with the synthesis of pentadepsipeptide peptidoglycan precursors ending in D-Ala-D-Lac, as demonstrated by D,D-dipeptidase activities, high-pressure liquid chromatography, and mass spectrometry. The precursors differed from those in enterococci by the presence of diaminopimelic acid instead of lysine in the peptide chain. Altogether, the results are compatible with the notion that van operons in soil Paenibacillus strains and in enterococci have evolved from a common ancestor.

Soot on snow in Iceland: First results on black carbon and organic carbon in Iceland 2016 snow and ice samples, including the glacier Solheimajökull

NASA Astrophysics Data System (ADS)

Meinander, Outi; Dagsson-Waldhauserova, Pavla; Gritsevich, Maria; Aurela, Minna; Arnalds, Olafur; Dragosics, Monika; Virkkula, Aki; Svensson, Jonas; Peltoniemi, Jouni; Kontu, Anna; Kivekäs, Niku; Leppäranta, Matti; de Leeuw, Gerrit; Laaksonen, Ari; Lihavainen, Heikki; Arslan, Ali N.; Paatero, Jussi

2017-04-01

New results on black carbon (BC) and organic carbon (OC) on snow and ice in Iceland in 2016 will be presented in connection to our earlier results on BC and OC on Arctic seasonal snow surface, and in connection to our 2013 and 2016 experiments on effects of light absorbing impurities, including Icelandic dust, on snow albedo, melt and density. Our sampling included the glacier Solheimajökull in Iceland. The mass balance of this glacier is negative and it has been shrinking during the last 20 years by 900 meters from its southwestern corner. Icelandic snow and ice samples were not expected to contain high concentrations of BC, as power generation with domestic renewable water and geothermal power energy sources cover 80 % of the total energy consumption in Iceland. Our BC results on filters analyzed with a Thermal/Optical Carbon Aerosol Analyzer (OC/EC) confirm this assumption. Other potential soot sources in Iceland include agricultural burning, industry (aluminum and ferroalloy production and fishing industry), open burning, residential heating and transport (shipping, road traffic, aviation). On the contrary to low BC, we have found high concentrations of organic carbon in our Iceland 2016 samples. Some of the possible reasons for those will be discussed in this presentation. Earlier, we have measured and reported unexpectedly low snow albedo values of Arctic seasonally melting snow in Sodankylä, north of Arctic Circle. Our low albedo results of melting snow have been confirmed by three independent data sets. We have explained these low values to be due to: (i) large snow grain sizes up to 3 mm in diameter (seasonally melting snow); (ii) meltwater surrounding the grains and increasing the effective grain size; (iii) absorption caused by impurities in the snow, with concentration of elemental carbon (black carbon) in snow of 87 ppb, and organic carbon 2894 ppb. The high concentrations of carbon were due to air masses originating from the Kola Peninsula, Russia, where mining and refining industries are located. SNICAR-model showed that the impurities absorb irradiance the more the shorter the wavelength. We have also presented a hypothesis that soot can decrease the liquid-water retention capacity of melting snow. There we also presented data, where both the snow density and elemental carbon content were measured. In our snow density related experiments, artificially added light-absorbing impurities decreased the density of seasonally melting natural snow. No relationship was found in case of natural non-melting snow. Our experimental results on Icelandic volcanic ash have showed that Eyjafjällajökull ash with grain size smaller than 500 μm insulated the ice below at a thickness of 9-15 mm (called as 'critical thickness'). For the 90 μm grain size, the insulation thickness was 13 mm. The maximum melt occurred at thickness of 1mm for the larger particles, and at the thickness of < 1-2 mm for the smaller particles (called as 'effective thickness'). Earlier, similar threshold dust layer thickness values have been given for Mt St Helens (1980) ash, and Hekla (1947) tephra, but our results were the first ones reported for the Eyjafjällajökull ash. In Iceland, the dust layers in the nature can be from mm scale up to tens of meters. Our results clearly demonstrate how important it is in the Arctic to perform measurements of BC, OC, and dust in the snow to fully understand the effects of light absorbing impurities on the cryosphere.

Diversity of Tn1546 in vanA-positive Enterococcus faecium clinical isolates with VanA, VanB, and VanD phenotypes and susceptibility to vancomycin.

PubMed

Cha, J O; Yoo, J I; Kim, H K; Kim, H S; Yoo, J S; Lee, Y S; Jung, Y H

2013-10-01

To investigate diversity in the vanA cluster in Enterococcus faecium isolates from nontertiary hospitals. We identified 43 vanA-positive Ent. faecium isolates, including two vancomycin-susceptible isolates, from hospitals between 2003 and 2006. Of these isolates, >85% were resistant to ampicillin, erythromycin and ciprofloxacin. The vanA cluster was classified into six types using overlapping PCR, but the prototype transposon Tn1546 was not found. Most vanA-positive vancomycin-resistant Enterococcus (VRE) carried IS1216V and belonged to Type III (58·1%) or Type II (20·9%). vanY, vanZ and IS1216V were observed in the left and right ends of Type III with long-range PCR. IS1216V was also observed within vanS and vanX in the two vancomycin-susceptible isolates and in two vancomycin-resistant isolates. No VRE isolates with VanB and VanD phenotypes contained point mutations in vanS, unlike in previous reports. Sequence types (STs) of all isolates belonged to clonal complex 17, and ST78 was predominant. Insertion sequences, especially IS1216V, cause structural variation in the vanA cluster. We report the first observation of vanY and vanZ at the left end of Tn1546 in clinical isolates. This is the first report of the frequency of vancomycin resistance and diversity of Tn1546 in vanA-positive Ent. faecium isolates from nontertiary hospitals. © 2013 The Society for Applied Microbiology.

OMEGACAM and Gravitational Lensing

NASA Astrophysics Data System (ADS)

Christen, Fabrice Frédéric Thiébaut

2007-04-01

Het proefschrift van Fabrice Christen gaat over de ontwikkeling van nieuwe methoden voor het corrigeren van (digitale) foto's van melkwegstelsels. Met deze methoden kunnen de beelden uit het heelal beter worden geanalyseerd. Het eerste gedeelte is gewijd aan het werk dat bij ESO is uitgevoerd aan de CCD's van de OmegaCAM camera, het enige instrument van de VST. OmegaCAM is een optische groothoekcamera met een beeldveld van een vierkante graad, opgebouwd uit een mozaiek van 8 bij 4 CCD's. Van elk onderdeel moeten alle kenmerken volledig bekend zijn voordat het in het CCD mozaiek geplaatst kan worden. In het tweede deel van dit proefschrift wordt de ontwikkeling van een nieuwe methode voor het corrigeren van de ``point-spread function'' (PSF) en schatten van de ellipticiteit van de melkwegstelsels besproken. De nieuwe techniek wordt getest en vergeleken met een door sterrenkundigen algemeen gebruikte methode in het veld van zwaartekrachtslenzen, de Kaiser, Squire en Broadhurst (KSB) methode. De nieuwe methode, gebaseerd op shapelet ontleding (vergelijkbaar met wavelet ontleding), gaat verder, en is sneller en theoretisch preciezer dan de KSB methode. Door gebruik te maken van de gecorrigeerde ellipticiteit, kunnen we een statistische analyse uitvoeren om er een kosmisch vervormingssignaal uit te halen. De licht vervormde beelden van de melkwegstelsels bewij zen dat de niet-homogene massaverdeling op megaparsec-schaal voornamelijk bestaat uit grote hoeveelheden donkere materie. Verder vergelijken we de schattingen van de ellipticiteit van de shapelet en KSB methode. Bovendien voeren we ook nog een melkwegstelsel-melkwegstelsel lens analyse uit op de 50 VLT Fors1 afbeeldingen en slagen we erin de belangrijkste eigenschappen van de halo's van de stelsels, die zich op een afstand van een- tot tweeduizend megaparsec (1 parsec = 3,26 lichtjaar = 3,085 x 10^16 meter) bevinden, te bepalen door gebruik te maken van twee modellen van melkwegstelselhalo's. Vergeleken met andere overzichtsmetingen vinden we vergelijkbare resultaten.

Beslisbevoegdheden en Verantwoordelijkheden van de Uitgestegen Soldaat. Deel A: Verplaatsen van Beslisbevoegdheden (Authority and Responsibility of the Dismounted Soldier. Part A. Empowering the Dismounted Soldier)

DTIC Science & Technology

2007-04-01

en verantwoordelijkheden van de uitgestegen soldaat Deel A: verplaatsen van beslisbevoegdheden Datumn april 2007 Auteur (s) R. de Bruin ITE. van Bernmel...Admiraal, Bureau SMP Auteur (s) R. de Bruin Program maleider Projectleider I.E. van Bemnmel dr. W.A. Lotens, A.J. van Vliet, A.J. van Vijet TNO Defensie en...Leadership Theory en wordt relevant geacht voor de ontvangers van aanvullende beslisbevoegdheden. 2.1.3 Het oogmerk van de hogere commandant Een ander

Investigating La Réunion Hot Spot From Crust to Core

NASA Astrophysics Data System (ADS)

Barruol, Guilhem; Sigloch, Karin

2013-06-01

Whether volcanic intraplate hot spots are underlain by deep mantle plumes continues to be debated 40 years after the hypothesis was proposed by Morgan [1972]. Arrivals of buoyant plume heads may have been among the most disruptive agents in Earth's history, initiating continental breakup, altering global climate, and triggering mass extinctions. Further, with the temporary shutdown of European air traffic in 2010 caused by the eruption of Eyjafjallajökull, a geologically routine eruption in the tail end of the presumed Iceland plume, the world witnessed an intrusion of hot spot activity into modern-day life.

A distinctive dual-channel quorum-sensing system operates in Vibrio anguillarum.

PubMed

Croxatto, Antony; Pride, John; Hardman, Andrea; Williams, Paul; Cámara, Miguel; Milton, Debra L

2004-06-01

Many bacterial cells communicate using diffusible signal molecules to monitor cell population density via a process termed quorum sensing. In marine Vibrio species, the Vibrio harveyi-type LuxR protein is a key player in a quorum-sensing phosphorelay cascade, which controls the expression of virulence, symbiotic and survival genes. Previously, we characterized Vibrio anguillarum homologues of LuxR (VanT) and LuxMN (VanMN) and, in this study, we have identified homologues of LuxPQ (VanPQ) and LuxOU (VanOU). In contrast to other Vibrio species, vanT was expressed at low cell density and showed no significant induction as the cell number increased. In addition, although the loss of VanO increased vanT expression, the loss of VanU, unexpectedly, decreased it. Both VanN and VanQ were required for repression of vanT even in a vanU mutant, suggesting an alternative route for VanNQ signal transduction other than via VanU. VanT negatively regulated its own expression by binding and repressing the vanT promoter and by binding and activating the vanOU promoter. The signal relay results in a cellular response as expression of the metalloprotease, empA, was altered similar to that of vanT in all the mutants. Consequently, the V. anguillarum quorum-sensing phosphorelay systems work differently from those of V. harveyi and may be used to limit rather than induce vanT expression.

Dutch Anthropometry for Vehicle Design and Evaluation

DTIC Science & Technology

2008-10-01

middelen Beschrijving van de werkzaamheden Uitgaande van afmetingen van Nederlanders zijn grenswaarden voor negen paspoppen. met vanSrende...vastgesteld voor het jaar 2015 Hierbij is uitgegaan van een Nederlands antropometrisch bestand (NedScan) Resultaten en conclusies Het resultaat is een kort... Nederlands antropometrisch bestand (NedScan) en van lichaamsafmetingen van goedgekeurde K.L rekruten. De grenswaarden omvatten 95% van dat Nederlandse

19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international traffic; repair components. (a)(1) Lift vans, cargo vans, shipping tanks, skids, pallets, caul...

19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international traffic; repair components. (a)(1) Lift vans, cargo vans, shipping tanks, skids, pallets, caul...

Fast Determination of the Element Excitation of an Active Phased Array Antenna

DTIC Science & Technology

1991-03-01

elementenexcitatie te, bepalen: de amplitude en fase van het elektrische ven-e veld moeten gemeten warden in slechts I richting in het verre veld van de ...Page 3 rapport no FEL-91-BO38 titel Een snelle bepaling van de excitatie van de elenienten van cen actieve phased array antenne auteur(s) I. J.G. van...van der Spek Onderzoek uItgevoerd door Ir. J.G. van Hezewijk SAMENVATIING (ONGERUBRICEERD) Het verre veld stralingsdiagram van een actieve phased array

Amino acid substitutions in the VanS sensor of the VanA-type vancomycin-resistant Enterococcus strains result in high-level vancomycin resistance and low-level teicoplanin resistance.

PubMed

Hashimoto, Y; Tanimoto, K; Ozawa, Y; Murata, T; Ike, Y

2000-04-15

The vancomycin-resistant enterococci GV1, GV2 and GV3, which were isolated from droppings from broiler farms in Japan have been characterized as VanA-type VRE, which express high-level vancomycin resistance (256 or 512 microg ml(-1), MIC) and low-level teicoplanin resistance (1 or 2 microg ml(-1), MIC). The vancomycin resistances were encoded on plasmids. The vancomycin resistance conjugative plasmid pMG2 was isolated from the GV2 strain. The VanA determinant of pMG2 showed the same genetic organization as that of the VanA genes encoded on the representative transposon Tn1546, which comprises vanRSHAXYZ. The nucleotide sequences of all the genes, except the gene related to the vanS gene on Tn1546, were completely identical to the genes encoded on Tn1546. Three amino acid substitutions in the N-terminal region of the deduced VanS were detected in the nucleotide sequence of vanS encoded on pMG2. There were also three amino acid substitutions in the vanS gene of the GV1 and GV3 strains in the same positions as in the vanS gene of pMG2. Vancomycin induced the increased teicoplanin resistance in these strains.

Presence of the vancomycin resistance gene cluster vanC1, vanXYc, and vanT in Enterococcus casseliflavus.

PubMed

Hölzel, Christina; Bauer, Johann; Stegherr, Eva-Maria; Schwaiger, Karin

2014-04-01

The three chromosomally located clustered genes vanC1, vanXYc, and vanT confer intrinsic resistance to vancomycin and are used for species identification of Enterococcus gallinarum. In this study, 28 strains belonging to the E. gallinarum/casseliflavus group isolated from cloacal swabs from laying hens were screened for the presence of vanC1. As confirmed by species-specific multiplex PCR, 11 vanC1-positive strains were identified as E. gallinarum. Surprisingly, one yellow pigmented strain, verified as E. casseliflavus by species-specific multiplex PCR, was also vanC1 positive; vanXYc and vanT were additionally detectable in this strain. To our knowledge, this is the first report of vanC1, vanXYc, and vanT in E. casseliflavus. The minimum inhibitory concentration of vancomycin was 4 mg/L. Real-time reverse transcription-PCR revealed that none of the clustered genes was expressed in this strain. Even if the genes seem not to be active, there is a certain risk that they will be transferred to other bacteria where they might be functionally expressed. Therefore, it may be advisable to expand the search for vanC1, vanXYc, and vanT from E. gallinarum to other (enterococcal) species. This study confirms that enterococci live up to their name as being reservoir bacteria and should therefore always be closely monitored.

The Local Group in LCDM - Shapes and masses of dark halos

NASA Astrophysics Data System (ADS)

Vera-Ciro, Carlos Andrés

2013-01-01

In dit proefschrift bestuderen we de eigenschappen van donkere materie halo's in het LCDM paradigma. Het eerste deel richt zich op de vorm van de massadistributie van dergelijke objecten. We hebben gevonden dat de vorm van ge"isoleerde Melkweg-achtige donkere materie halo's significant afwijkt van bolsymmetrie. De lokale omgeving heeft invloed op de halo's en deze worden daarbij sterk be"invloed door de manier waarop massa aangroeit. We hebben ook de structuur en de baanstructuur van de satellieten van dergelijke halo's in detail onderzocht. In het algemeen zijn deze objecten sferischer dan de halo's zelf. Ze vertonen ook duidelijke afdrukken van getijdenwerking in zowel hun geometrische vorm als in de baanstructuur. Daarna gebruiken we het aantal massieve objecten rond de Melkweg om limieten te zetten op de totale massa van de donkere materie halo van de Melkweg. De eigenschappen van de massaverdeling van de Melkweg worden verder onderzocht in het laatste hoofdstuk. Daar maken we gebruik van de Sagittarius sterstroom om de vorm van de galactische potentiaal beter te bepalen. We komen met een nieuw model dat rekening houdt met de galactische schijf en de invloed van satellietstelsels en die bovendien consistent is met het LCDM paradigma.

Co-colonization of vanA and vanB Enterococcus faecium of clonal complex 17 in a patient with bacteremia due to vanA E. faecium.

PubMed

Seol, Chang Ahn; Park, Jeong Su; Sung, Heungsup; Kim, Mi-Na

2014-06-01

A 53-year-old Vietnamese man with liver cirrhosis was transferred from a Vietnamese hospital to our tertiary care hospital in Korea in order to undergo a liver transplantation. Bacteremia due to vanA Enterococcus faecium was diagnosed, and stool surveillance cultures for vancomycin-resistant enterococci (VRE) were positive for both vanA and vanB E. faecium. Pulsed-field gel electrophoresis analysis revealed that the 2 vanA VRE isolates from the blood and stool were clonal, but the vanB VRE was unrelated to the vanA VRE. vanA and vanB VRE were ST64 and ST18, single-allele variations of clonal complex 17, respectively. This is the first case report of vanA VRE bacteremia in a Vietnamese patient and demonstrates the reemergence of vanB VRE since a single outbreak occurred 15years ago in Korea. The reemergence of vanB VRE emphasizes the importance of VRE genotyping to prevent the spread of new VRE strains. Copyright © 2014 Elsevier Inc. All rights reserved.

Biochemical and Genetic Characterization of the vanC-2 Vancomycin Resistance Gene Cluster of Enterococcus casseliflavus ATCC 25788

PubMed Central

Dutta, Ireena; Reynolds, Peter E.

2002-01-01

The vanC-2 cluster of Enterococcus casseliflavus ATCC 25788 consisted of five genes (vanC-2, vanXYC-2, vanTC-2, vanRC-2, and vanSC-2) and shared the same organization as the vanC cluster of E. gallinarum BM4174. The proteins encoded by these genes displayed a high degree of amino acid identity to the proteins encoded within the vanC gene cluster. The putative d,d-dipeptidase-d,d-carboxypeptidase, VanXYC-2, exhibited 81% amino acid identity to VanXYC, and VanTC-2 displayed 65% amino acid identity to the serine racemase, VanT. VanRC-2 and VanSC-2 displayed high degrees of identity to VanRC and VanSC, respectively, and contained the conserved residues identified as important to their function as a response regulator and histidine kinase, respectively. Resistance to vancomycin was expressed inducibly in E. casseliflavus ATCC 25788 and required an extended period of induction. Analysis of peptidoglycan precursors revealed that UDP-N-acetylmuramyl-l-Ala-δ-d-Glu-l-Lys-d-Ala-d-Ser could not be detected until several hours after the addition of vancomycin, and its appearance coincided with the resumption of growth. The introduction of additional copies of the vanTC-2 gene, encoding a putative serine racemase, and the presence of supplementary d-serine in the growth medium both significantly reduced the period before growth resumed after addition of vancomycin. This suggested that the availability of d-serine plays an important role in the induction process. PMID:12234834

Characterisation of the selective binding of antibiotics vancomycin and teicoplanin by the VanS receptor regulating type A vancomycin resistance in the enterococci.

PubMed

Hughes, C S; Longo, E; Phillips-Jones, M K; Hussain, R

2017-08-01

A-type resistance towards "last-line" glycopeptide antibiotic vancomycin in the leading hospital acquired infectious agent, the enterococci, is the most common in the UK. Resistance is regulated by the VanR A S A two-component system, comprising the histidine sensor kinase VanS A and the partner response regulator VanR A . The nature of the activating ligand for VanS A has not been identified, therefore this work sought to identify and characterise ligand(s) for VanS A . In vitro approaches were used to screen the structural and activity effects of a range of potential ligands with purified VanS A protein. Of the screened ligands (glycopeptide antibiotics vancomycin and teicoplanin, and peptidoglycan components N-acetylmuramic acid, D-Ala-D-Ala and Ala-D-y-Glu-Lys-D-Ala-D-Ala) only glycopeptide antibiotics vancomycin and teicoplanin were found to bind VanS A with different affinities (vancomycin 70μM; teicoplanin 30 and 170μM), and were proposed to bind via exposed aromatic residues tryptophan and tyrosine. Furthermore, binding of the antibiotics induced quicker, longer-lived phosphorylation states for VanS A , proposing them as activators of type A vancomycin resistance in the enterococci. Copyright © 2017 Diamond Light Source Ltd. Published by Elsevier B.V. All rights reserved.

SEVIRI 4D-var assimilation analysing the April 2010 Eyjafjallajökull ash dispersion

NASA Astrophysics Data System (ADS)

Lange, Anne Caroline; Elbern, Hendrik

2016-04-01

We present first results of four dimensional variational (4D-var) data assimilation analysis applying SEVIRI observations to the Eulerian regional chemistry and aerosol transport model EURAD-IM (European Air Pollution Dispersion - Inverse Model). Optimising atmospheric dispersion models in terms of volcanic ash transport predictions by observations is especially essential for the aviation industry and associated interests. Remote sensing satellite observations are instrumental for ash detection and monitoring. We choose volcanic ash column retrievals of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) because as infrared instrument on the geostationary satellite Meteosat Second Generation it delivers measurements with high temporal resolution during day and night. The retrieval method relies on the reverse absorption effect. In the framework of the national initiative ESKP (Earth System Knowledge Platform) and the European ACTRIS-2 (Aerosol, Clouds, and Trace gases Research InfraStructure) project, we developed new modules (forward and adjoint) within the EURAD-IM, which are able to process SEVIRI ash column data as observational input to the 4D-var system. The focus of the 4D-var analysis is on initial value optimisation of the volcanic ash clouds that were emitted during the explosive Eyjafjallajökull eruption in April 2010. This eruption caused high public interest because of air traffic closures and it was particularly well observed from many different observation systems all over Europe. Considering multiple observation periods simultaneously in one assimilation window generates a continuous trajectory in the phase space and ensures that past observations are considered within their uncertainties. Results are validated mainly by lidar (LIght Detection And Ranging) observations, both ground and satellite based.

Ash dispersal dynamics: state of the art and perspectives

NASA Astrophysics Data System (ADS)

Sulpizio, R.

2013-05-01

Volcanic ash, during dispersal and deposition, is among the major hazards from explosive eruptions. Volcanic ash fallout can disrupt communities downwind, interrupt surface transportation networks and lead to closure of airports. Airborne ash seriously threatens modern jet aircraft in flight. In several documented cases, encounters between aircraft and volcanic clouds have resulted in engine flameout and near crashes, so there is a need to accurately predict the trajectory of volcanic ash clouds in order to improve aviation safety and reduce economic losses. The ash clouds affect aviation even in distal regions, as demonstrated by several eruptions with far-range dispersal. Recent examples include Crater Peak 1992, Tungurahua 1999-2001, Mount Cleveland 2001, Chaitén 2008, Eyjafjallajökull 2010, Grimsvötn 2011, and Cordón-Caulle 2011. Amongst these, the April-May 2010 eruption of Eyjafjallajökull in Iceland provoked the largest civil aviation breakdown. Accumulation of tephra can produce roof collapse, interruption of lifelines (roads, railways, etc.), disruption to airport operations, and damage to communications and electrical power lines. Deposition of ash decreases soil permeability, increases surface runoff, and promotes floods. Ash leaching can result in the pollution of water resources, damage to agriculture, pastures, and livestock, impinge on aquatic ecosystems, and alteration of the geochemical environment on the seafloor. Despite the potential big impact, the dispersal dynamics of volcanic ash is still an unsolved problem for volcanologists, which claims for fiture high level research. Here, a critical overview about models (field, experimental and numerical) for inversion of field data to gain insights on physics of dispersal of volcanic ash is proposed. A special focus is devoted to some physical parameters that are far from a satisfactory inversion (e.g. reconstruction of total grain size distribution), and clues for future research are suggested.

Ash-plume dynamics and eruption source parameters by infrasound and thermal imagery: The 2010 Eyjafjallajökull eruption

NASA Astrophysics Data System (ADS)

Ripepe, M.; Bonadonna, C.; Folch, A.; Delle Donne, D.; Lacanna, G.; Marchetti, E.; Höskuldsson, A.

2013-03-01

During operational ash-cloud forecasting, prediction of ash concentration and total erupted mass directly depends on the determination of mass eruption rate (MER), which is typically inferred from plume height. Uncertainties for plume heights are large, especially for bent-over plumes in which the ascent dynamics are strongly affected by the surrounding wind field. Here we show how uncertainties can be reduced if MER is derived directly from geophysical observations of source dynamics. The combination of infrasound measurements and thermal camera imagery allows for the infrasonic type of source to be constrained (a dipole in this case) and for the plume exit velocity to be calculated (54-142 m/s) based on the acoustic signal recorded during the 2010 Eyjafjallajökull eruption from 4 to 21 May. Exit velocities are converted into MER using additional information on vent diameter (50±10 m) and mixture density (5.4±1.1 kg/m3), resulting in an average ∼9×105 kg/s MER during the considered period of the eruption. We validate our acoustic-derived MER by using independent measurements of plume heights (Icelandic Meteorological Office radar observations). Acoustically derived MER are converted into plume heights using field-based relationships and a 1D radially averaged buoyant plume theory model using a reconstructed total grain size distribution. We conclude that the use of infrasonic monitoring may lead to important understanding of the plume dynamics and allows for real-time determination of eruption source parameters. This could improve substantially the forecasting of volcano-related hazards, with important implications for civil aviation safety.

Present day geodynamics in Iceland monitored by a permanent network of continuous GPS stations

NASA Astrophysics Data System (ADS)

Völksen, Christof; Árnadóttir, Thóra; Geirsson, Halldór; Valsson, Guðmundur

2009-12-01

Iceland is located on the Mid-Atlantic Ridge and thereby offers a rare opportunity to study crustal movements at a divergent plate boundary. Iceland is not only characterized by the divergence of the Eurasian and North American Plates, as several active volcanoes are located on the island. Moderate size earthquakes occur in the transform zones, causing measurable crustal deformation. In 1999 the installation of a permanent network of continuous GPS stations (ISGPS) was initiated in order to observe deformation due to unrest in the Hengill volcanic system and at the Katla volcano. The ISGPS network has been enlarged over the years and consists today of more than 25 CGPS stations. Most of the stations are located along the plate boundary, where most of the active deformation takes place. Uplift due to post-glacial rebound due to the melting of the largest glacier in Europe, Vatnajökull, is also detected by the ISGPS network. This study presents results from analysis of 9 years of data from the ISGPS network, in the global reference frame PDR05, which has been evaluated by the Potsdam-Dresden-Reprocessing group with reprocessed GPS data only. We thus determine subsidence or land uplift in a global frame. The horizontal station velocities clearly show spreading across the plate boundary of about 20 mm/a. Stations in the vicinity of the glacier Vatnajökull indicate uplift in the range of 12 mm/a, while a station in the central part of Iceland shows uplift rates of about 25 mm/a. Tide gauge readings in Reykjavik and current subsidence rates observed with CGPS agree also quite well.

Punctuated Holocene climate of Vestfirðir, Iceland, linked to internal/external variables and oceanographic conditions

NASA Astrophysics Data System (ADS)

Harning, David J.; Geirsdóttir, Áslaug; Miller, Gifford H.

2018-06-01

Emerging Holocene paleoclimate datasets point to a non-linear response of Icelandic climate against a background of steady orbital cooling. The Vestfirðir peninsula (NW Iceland) is an ideal target for continued climate reconstructions due to the presence of a small ice cap (Drangajökull) and numerous lakes, which provide two independent means to evaluate existing Icelandic climate records and to constrain the forcing mechanisms behind centennial-scale cold anomalies. Here, we present new evidence for Holocene expansions of Drangajökull based on 14C dates from entombed dead vegetation as well as two continuous Holocene lake sediment records. Lake sediments were analyzed for both bulk physical (MS) and biological (%TOC, δ13C, C/N, and BSi) parameters. Composite BSi and C/N records from the two lakes yield a sub-centennial qualitative perspective on algal (diatom) productivity and terrestrial landscape stability, respectively. The Vestfirðir lake proxies suggest initiation of the Holocene Thermal Maximum by ∼8.8 ka with subsequent and pronounced cooling not apparent until ∼3 ka. Synchronous periods of reduced algal productivity and accelerated landscape instability point to cold anomalies centered at ∼8.2, 6.6, 4.2, 3.3, 2.3, 1.8, 1, and 0.25 ka. Triggers for cold anomalies are linked to variable combinations of freshwater pulses, low total solar irradiance, explosive and effusive volcanism, and internal modes of climate variability, with cooling likely sustained by ocean/sea-ice feedbacks. The climate evolution reflected by our glacial and organic proxy records corresponds closely to marine records from the North Iceland Shelf.

Artificial cloud test confirms volcanic ash detection using infrared spectral imaging

PubMed Central

Prata, A. J.; Dezitter, F.; Davies, I.; Weber, K.; Birnfeld, M.; Moriano, D.; Bernardo, C.; Vogel, A.; Prata, G. S.; Mather, T. A.; Thomas, H. E.; Cammas, J.; Weber, M.

2016-01-01

Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m−3 were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft. PMID:27156701

Artificial cloud test confirms volcanic ash detection using infrared spectral imaging.

PubMed

Prata, A J; Dezitter, F; Davies, I; Weber, K; Birnfeld, M; Moriano, D; Bernardo, C; Vogel, A; Prata, G S; Mather, T A; Thomas, H E; Cammas, J; Weber, M

2016-05-09

Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m(-3) were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft.

Members of the Genera Paenibacillus and Rhodococcus Harbor Genes Homologous to Enterococcal Glycopeptide Resistance Genes vanA and vanB

PubMed Central

Guardabassi, L.; Christensen, H.; Hasman, H.; Dalsgaard, A.

2004-01-01

Genes homologous to enterococcal glycopeptide resistance genes vanA and vanB were found in glycopeptide-resistant Paenibacillus and Rhodococcus strains from soil. The putative d-Ala:d-Lac ligase genes in Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B were closely related to vanA (92 and 87%) and flanked by genes homologous to vanH and vanX in vanA operons. PMID:15561881

Members of the genera Paenibacillus and Rhodococcus harbor genes homologous to enterococcal glycopeptide resistance genes vanA and vanB.

PubMed

Guardabassi, L; Christensen, H; Hasman, H; Dalsgaard, A

2004-12-01

Genes homologous to enterococcal glycopeptide resistance genes vanA and vanB were found in glycopeptide-resistant Paenibacillus and Rhodococcus strains from soil. The putative D-Ala:D-Lac ligase genes in Paenibacillus thiaminolyticus PT-2B1 and Paenibacillus apiarius PA-B2B were closely related to vanA (92 and 87%) and flanked by genes homologous to vanH and vanX in vanA operons.

Biochemical and genetic characterization of the vanC-2 vancomycin resistance gene cluster of Enterococcus casseliflavus ATCC 25788.

PubMed

Dutta, Ireena; Reynolds, Peter E

2002-10-01

The vanC-2 cluster of Enterococcus casseliflavus ATCC 25788 consisted of five genes (vanC-2, vanXY(C-2), vanT(C-2), vanR(C-2), and vanS(C-2)) and shared the same organization as the vanC cluster of E. gallinarum BM4174. The proteins encoded by these genes displayed a high degree of amino acid identity to the proteins encoded within the vanC gene cluster. The putative D,D-dipeptidase-D,D-carboxypeptidase, VanXY(C-2), exhibited 81% amino acid identity to VanXY(C), and VanT(C-2) displayed 65% amino acid identity to the serine racemase, VanT. VanR(C-2) and VanS(C-2) displayed high degrees of identity to VanR(C) and VanS(C), respectively, and contained the conserved residues identified as important to their function as a response regulator and histidine kinase, respectively. Resistance to vancomycin was expressed inducibly in E. casseliflavus ATCC 25788 and required an extended period of induction. Analysis of peptidoglycan precursors revealed that UDP-N-acetylmuramyl-L-Ala-delta-D-Glu-L-Lys-D-Ala-D-Ser could not be detected until several hours after the addition of vancomycin, and its appearance coincided with the resumption of growth. The introduction of additional copies of the vanT(C-2) gene, encoding a putative serine racemase, and the presence of supplementary D-serine in the growth medium both significantly reduced the period before growth resumed after addition of vancomycin. This suggested that the availability of D-serine plays an important role in the induction process.

Incidence of Acute Kidney Injury among Patients Treated with Piperacillin-Tazobactam or Meropenem in Combination with Vancomycin.

PubMed

Rutter, W Cliff; Burgess, David S

2018-07-01

Acute kidney injury (AKI) increases during empirical antimicrobial therapy with the combination of piperacillin-tazobactam (TZP) and vancomycin (VAN) compared to the number of incidences with monotherapy or the combination of cefepime and VAN. Limited data regarding the impact of meropenem (MEM) combined with VAN exist. This study examined the AKI incidence among patients treated with MEM plus VAN (MEM+VAN) or TZP+VAN. Data were collected from the University of Kentucky Center for Clinical and Translational Science Enterprise Data Trust from September 2007 through October 2015. Adults without previous renal disease who received MEM+VAN or TZP+VAN for at least 2 days were included. AKI was assessed using risk, injury, failure, loss, and end-stage (RIFLE) criteria. Inverse probability of treatment weighting was utilized to control for differences between groups. In total, 10,236 patients met inclusion criteria, with 9,898 receiving TZP+VAN and 338 receiving MEM+VAN. AKI occurred in 15.4% of MEM+VAN patients and in 27.4% of TZP+VAN patients ( P < 0.001). TZP+VAN was associated with increased AKI compared to the level with MEM+VAN (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.82 to 3.52), after controlling for confounders. Use of MEM+VAN should be considered an appropriate alternative therapy to TZP+VAN if nephrotoxicity is a major concern. The results of this study demonstrate that judicial use of TZP+VAN for empirical coverage of infection is needed. Copyright © 2018 American Society for Microbiology.

Revision of the subfamily Opiinae (Hymenoptera, Braconidae) from Hunan (China), including thirty-six new species and two new genera

PubMed Central

Li, Xi-Ying; van Achterberg, Cornelis; Tan, Ji-Cai

2013-01-01

Abstract The species of the subfamily Opiinae (Hymenoptera: Braconidae) from Hunan (Oriental China) are revised and illustrated. Thirty-six new species are described: Apodesmia bruniclypealis Li & van Achterberg, sp. n., Apodesmia melliclypealis Li & van Achterberg, sp. n., Areotetes albiferus Li & van Achterberg, sp. n., Areotetes carinuliferus Li & van Achterberg, sp. n., Areotetes striatiferus Li & van Achterberg, sp. n., Coleopioides diversinotum Li & van Achterberg, sp. n., Coleopioides postpectalis Li & van Achterberg, sp. n., Fopius dorsopiferus Li, van Achterberg & Tan, sp. n., Indiopius chenae Li & van Achterberg, sp. n., Opiognathus aulaciferus Li & van Achterberg, sp. n., Opiognathus brevibasalis Li & van Achterberg, sp. n., Opius crenuliferus Li & van Achterberg, sp. n., Opius malarator Li, van Achterberg & Tan, sp. n., Opius monilipalpis Li & van Achterberg, sp. n., Opius pachymerus Li & van Achterberg, sp. n., Opius songi Li & van Achterberg, sp. n., Opius youi Li & van Achterberg, sp. n., Opius zengi Li & van Achterberg, sp. n., Phaedrotoma acuticlypeata Li & van Achterberg, sp. n., Phaedrotoma angiclypeata Li & van Achterberg, sp. n., Phaedrotoma antenervalis Li & van Achterberg, sp. n., Phaedrotoma depressiclypealis Li & van Achterberg, sp. n., Phaedrotoma flavisoma Li & van Achterberg, sp. n., Phaedrotoma nigrisoma Li & van Achterberg, sp. n., Phaedrotoma protuberator Li & van Achterberg, sp. n., Phaedrotoma rugulifera Li & van Achterberg, sp. n., Li & van Achterberg,Phaedrotoma striatinota Li & van Achterberg, sp. n., Phaedrotoma vermiculifera Li & van Achterberg, sp. n., Rhogadopsis latipennis Li & van Achterberg, sp. n., Rhogadopsis longicaudifera Li & van Achterberg, sp. n., Rhogadopsis maculosa Li, van Achterberg & Tan, sp. n., Rhogadopsis obliqua Li & van Achterberg, sp. n., Rhogadopsis sculpturator Li & van Achterberg, sp. n., Utetes longicarinatus Li & van Achterberg, sp. n. and Xynobius notauliferus Li & van Achterberg, sp. n. Areotetes van Achterberg & Li, gen. n. (type species: Areotetes carinuliferus sp. n.) and Coleopioides van Achterberg & Li, gen. n. (type species: Coleopioides postpectalis sp. n. are described. All species are illustrated and keyed. In total 30 species of Opiinae are sequenced and the cladograms are presented. Neopius Gahan, 1917, Opiognathus Fischer, 1972, Opiostomus Fischer, 1972, and Rhogadopsis Brèthes, 1913, are treated as a valid genera based on molecular and morphological differences. Opius vittata Chen & Weng, 2005 (not Opius vittatus Ruschka, 1915), Opius ambiguus Weng & Chen, 2005 (not Wesmael, 1835) and Opius mitis Chen & Weng, 2005 (not Fischer, 1963) are primary homonymsandarerenamed into Phaedrotoma depressa Li & van Achterberg, nom. n., Opius cheni Li & van Achterberg, nom. n. andOpius wengi Li & van Achterberg, nom. n., respectively. Phaedrotoma terga (Chen & Weng, 2005) comb. n.,Diachasmimorpha longicaudata (Ashmead, 1905) and Biosteres pavitita Chen & Weng, 2005, are reported new for Hunan, Opiostomus aureliae (Fischer, 1957) comb. n. is new for China and Hunan; Xynobius maculipennis(Enderlein, 1912) comb. n. is new for Hunan and continental China and Rhogadopsis longuria (Chen & Weng, 2005) comb. n. is new for Hunan. The following new combinations are given: Apodesmia puncta (Weng & Chen, 2005) comb. n., Apodesmia tracta (Weng & Chen, 2005) comb. n., Areotetes laevigatus (Weng & Chen, 2005) comb. n., Phaedrotoma dimidia (Chen & Weng, 2005) comb. n., Phaedrotoma improcera (Weng & Chen, 2005) comb. n., Phaedrotoma amputata (Weng & Chen, 2005) comb. n., Phaedrotoma larga (Weng & Chen, 2005) comb. n., Phaedrotoma osculas (Weng & Chen, 2005) comb. n., Phaedrotoma postuma (Chen & Weng, 2005) comb. n., Phaedrotoma rugulosa (Chen & Weng, 2005) comb. n., Phaedrotoma tabularis (Weng & Chen, 2005) comb. n., Rhogadopsis apii (Chen & Weng, 2005) comb. n., Rhogadopsis dimidia (Chen & Weng, 2005) comb. n., Rhogadopsis diutia (Chen & Weng, 2005) comb. n., Rhogadopsis longuria (Chen & Weng, 2005) comb. n., Rhogadopsis pratellae(Weng & Chen, 2005) comb. n., Rhogadopsis pratensis (Weng & Chen, 2005) comb. n., Rhogadopsis sculpta (Chen & Weng, 2005) comb. n., Rhogadopsis sulcifer (Fischer, 1975) comb. n., Rhogadopsis tabidula(Weng & Chen, 2005) comb. n., Xynobius complexus (Weng & Chen, 2005) comb. n., Xynobius indagatrix (Weng & Chen, 2005) comb. n., Xynobius multiarculatus (Chen & Weng, 2005) comb. n. The following (sub)genera are synonymised: Snoflakopius Fischer, 1972, Jucundopius Fischer, 1984, Opiotenes Fischer, 1998, and Oetztalotenes Fischer, 1998, with Opiostomus Fischer, 1971; Xynobiotenes Fischer, 1998, with Xynobius Foerster, 1862; Allotypus Foerster, 1862, Lemnaphilopius Fischer, 1972, Agnopius Fischer, 1982, and Cryptognathopius Fischer, 1984, with Apodesmia Foerster, 1862; Nosopoea Foerster, 1862, Tolbia Cameron, 1907, Brachycentrus Szépligeti, 1907, Baeocentrum Schulz, 1911, Hexaulax Cameron, 1910, Coeloreuteus Roman, 1910, Neodiospilus Szépligeti, 1911, Euopius Fischer, 1967, Gerius Fischer, 1972, Grimnirus Fischer, 1972, Hoenirus Fischer, 1972, Mimirus Fischer, 1972, Gastrosema Fischer, 1972, Merotrachys Fischer, 1972, Phlebosema Fischer, 1972, Neoephedrus Samanta, Tamili, Saha & Raychaudhuri, 1983, Adontopius Fischer, 1984, Kainopaeopius Fischer, 1986, Millenniopius Fischer, 1996, and Neotropopius Fischer, 1999, with Phaedrotoma Foerster, 1862. PMID:23653521

Scatterometry

NASA Astrophysics Data System (ADS)

Stoffelen, Adrianus Cornelis Maria

1996-10-01

Een veelheid aan meteorologische metingen is dagelijks beschikbaar. De meeste van deze waarnemingen bevinden zich echter boven land, en met name windwaarnemingen boven de (Noord Atlantische) oceaan zijn schaars. Bij een westelijke luchtstroming is dit een duidelijke beperking voor de weers- en golfverwachtingen ten behoeve van Nederland. Juist dan is het gevaar voor bijvoorbeeld storm of overstroming het grootst. Ook in het aardse klimaatsysteem speelt de wind aan het oppervlak een grote rol en is de belangrijkste factor voor de aandrijving van de oceaancirculatie. De oceaancirculatie op zijn beurt is cruciaal voor de verschijnselen die samenhangen met bijvoorbeeld El Niño. Dit proefschift gaat over het scatterometer instrument dat vanuit de ruimte, zelfs onder een wolkendek, nauwkeurige en betrouwbare informatie geeft over de wind aan het oceaanoppervlak met een hoge mate van ruimtelijke consistentie. Tijdens de tweede wereldoorlog werden radars aan boord van schepen veelvuldig gebruikt voor de opsporing van vijandige vaartuigen. Hierbij werd vastgesteld dat de detectie slechter werd naarmate de wind aan het zeeoppervlak groter was. Proefondervindelijk was hiermee het principe van een wind scatterometer aangetoond. Al snel ontwikkelde zich dan ook de idee de wind aan het zeeoppervlak te meten met behulp van radar. Vanuit een vliegtuig of een satelliet word dan een microgolfbundel onder een schuine hoek naar het zeeoppervlak gestuurd. De microgolfstraling, met gewoonlijk een golflengte van enkele centimeters, wordt verstrooid aan het ruwe oppervlak, en een klein gedeelte van de uitgezonden puls keert terug naar het detectorgedeelte van de scatterometer. Het fysische fenomeen van belang voor de werking van de scatterometer is de aanwezigheid van zogeheten capillaire gavitatiegolven op het zeeoppervlak. Deze golven hebben een golflengte van enkele centimeters en reageren vrijwel instantaan op de sterkte van de wind. De verstrooiing van microgolven is op zijn beurt weer sterk afhankelijk van de amplitude van de capillaire golven. Bovendien blijken de capillaire golfjes over het algemeen gericht in lijn met de windrichting. Aldus bestaat er een verband tussen de hoeveelheid teruggestrooide energie en de windsterkte en -richting op enige hoogte. Een scatterometer instrument wordt zo ontworpen dat uit diverse metingen van het teruggestrooide vermogen, windsterkte en -richting afgeleid kunnen worden. Deze metingen kunnen dan eenvoudig vergeleken worden met bestaande windgegevens van boeien, schepen en weermodellen ter calibratie en validatie.?SAMENVATTING viii Overzicht In de loop der jaren zijn scatterometer instrumenten aan boord van verscheidene satellieten gelanceerd. De scatterometers op de ERS-1 en ERS-2 ("European Remote-sensing Satellite") hebben de langste staat van dienst en zijn sinds 1991 operationeel. Deze scatterometers (die identiek zijn) hebben ieder drie antennes, waarmee het oceaanoppervlak in drie verschillende richtingen bemeten wordt. Een punt op het aardoppervlak wordt eerst door de naar voren gerichte bundel belicht, dan door de naar opzij gerichte bundel, en als laatste door de naar achteren gerichte bundel. De drie metingen, verder kortweg aangeduid als trits, kunnen tegen elkaar worden uitgezet, hetgeen resulteert in een ruimtelijk (3D) plaatje. Door uitgekiende doorsneden te maken van deze ruimte kan de samenhang van de drie metingen kwalitatief worden bestudeerd. De drie metingen blijken dan inderdaad een sterke samenhang te vertonen die verklaard kan worden uit twee geofysische parameters. De drie metingen liggen namelijk in het algemeen dichtbij een hoornvormig (2D) oppervlak. De lengterichting van de hoorn blijkt voornamelijk te corresponderen met een variërende windsterkte (of ruwheid van de zee), en de kortste omtrek van de hoorn met een variërende windrichting (ofwel oriëntatie van de capillaire golfjes). De karakterisatie en modellering van dit oppervlak heeft geleid tot een aanzienlijke verbetering in de interpretatie van de scatterometer, zoals beschreven is in dit proefschrift. Hierboven is een uiterst simplistisch beeld gegeven van de fysica die van belang is bij de interpretatie van de scatterometer. Het eerste hoofdstuk van dit proefschrift beschrijft in meer detail de fysische modellering van belang bij de interpretatie van de scatterometer metingen. Ten eerste, de topografie van het zeeoppervlak is uitermate gecompliceerd en niet nauwkeurig te beschrijven met eenvoudige mathematische vergelijkingen. De capillaire golven hebben een andere fasesnelheid dan de langere golven en beide hebben hiermee een ingewikkelde dynamische interactie. Bij hogere windsnelheid breken de golven en ontstaan er schuimkoppen, hetgeen de fysische beschrijving verder compliceert. Ten tweede, de interactie van een schuin invallende microgolfbundel met dit gecompliceerde oppervlak is evenmin nauwkeurig te beschrijven. Zowel verstrooiing als reflectie kunnen een rol spelen. Ten derde, over de relatie tussen de amplitude van de capillaire golven en de wind op enige hoogte, laten we veronderstellen 10 m, is in de literatuur niet de overeenstemming tot in het gewenste detail. Bij lage windsnelheid zouden de oppervlaktespanning of variaties in de wind variabiliteit een rol kunnen spelen. Gezien de fysische complexiteit, is het niet verwonderlijk dat voor de interpretatie van scatterometer metingen statistische methoden hun opgang gevonden hebben. Dit proefschrift gaat met name in op deze methoden, en geeft, aan de hand van vijf wetenschappelijke publicaties, een tamelijk volledig beeld van de "state-of-the-art", zoals die bereikt is met de?SAMENVATTING ix ERS scatterometers (ERS-1 vanaf 17 juli 1991 en later ERS-2 vanaf 22 november 1995). Het derde hoofdstuk behandelt de visualisatie van de gemeten tritsen in de 3D meetruimte, de bepaling van de spreiding van de metingen rond het hoornvormige oppervlak, en de schatting van de meest waarschijnlijke "werkelijke" (of ruisvrije) trits bij het hoornvormige oppervlak gegeven de metingen en hun nauwkeurigheid (inversie). De perceptie dat de metingen met grote waarschijnlijkheid dichtbij een hoornvormig oppervlak liggen, vormt essentiële a priori informatie van belang voor de inversie. Een inversieprocedure gestoeld op waarschijnlijkheidstheorie is afgeleid. Verder worden aan de hand van de structuur van het hoornvormige oppervlak indicatoren bepaald, van belang voor de kwaliteitscontrole, instrumentbewaking, en de verdere verwerking van de gegevens. In de appendix wordt een methode besproken die beschrijft hoe, aan de hand van geselecteerde windgegevens en een goed wind-microgolf verband, ofwel transfer functie, de scatterometer verstrooiingsmetingen gecalibreerd kunnen worden boven de oceaan. Het blijkt dat deze calibratie, die per antenne wordt uitgevoerd, uiterst nauwkeurig is, en, wanneer toegepast, in de 3D meetruimte de verdeling van gemeten tritsen gemiddeld dichterbij de door de transfer functie gemodelleerde hoorn brengt. Dit levert een verbetert scatterometer wind product op. De methode was met name van groot belang voor de validatie en calibratie van de ERS-2 scatterometer, voordat de instrumentele calibratie was voltooid. Met behulp van een set windgegevens uit een weermodel en hun geschatte nauwkeurigheden, passend in locatie en tijd bij een set van scatterometer metingen en hun geschatte nauwkeurigheden, kan met quasi-lineaire schattingstheorie ("Maximum Likelihood Estimation") de meest waarschijnlijke wind-microgolf transfer functie worden afgeleid. De niet-lineariteit en onnauwkeurige formulering van de transfer functie, een niet-uniforme verdeling van invoergegevens, en een inaccurate formulering van de geschatte nauwkeurigheid kunnen hier een goed resultaat in de weg staan. Een nieuwe functie, genoemd CMOD4, wordt afgeleid in hoofdstuk IV. Een eerste eis die gesteld wordt aan een transfer functie, is dat het in de 3D meetruimte nauwkeurig bij de gemeten tritsen past. Wanneer de "fit" optimaal is zal het gecombineerde effect van meetonnauwkeurigheid en inversiefout kleiner zijn dan 0.5 m s -1 in de wind vector. CMOD4 blijkt binnen deze fout bij de metingen te passen. Een tweede eis is, dat voor een onafhankelijke gegevensset, het verschil tussen de geïnverteerde scatterometer wind en de bijpassende wind van bijvoorbeeld een weermodel zo klein mogelijk is. In de praktijk blijkt dat deze tweede eis impliciet volgt uit de eerste, maar ook dat de onnauwkeurigheid van de scatterometer wind met name wordt bepaald door de associatie van een locatie op de hoorn met een wind vector. De onnauwkeurigheid in de scatterometer wind kan dan ook goed beschreven worden in het wind domein.?SAMENVATTING x In hoofdstuk V wordt dit laatste verder uitgewerkt, en wordt gestreefd naar een gedetailleerde wind calibratie met behulp van in situ gegevens. Windgegevens bevatten doorgaans een relatief grote onnauwkeurigheid. Het wordt aangetoond dat ijking of regressie van zulke gegevens niet mogelijk is in een vergelijking van twee meetsystemen, tenzij de nauwkeurigheid van één van de twee meetsystemen bekend is. In de praktijk is dit meestal niet zo. Voor deze gevallen wordt een methode voorgesteld die uitgaat van de simultane vergelijking van drie meetsystemen. In dit geval kan zowel de ijking als een foutenmodel voor de drie meetsystemen worden opgelost. Toepassing van de methode laat zien dat de scatterometer wind afgeleid met behulp van CMOD4 ruwweg 5 % te laag is, en de oppervlaktewind van het gebruikte weermodel ongeveer 5 % te hoog. Het hoornvormige oppervlak blijkt te bestaan uit twee nauw samenvallende laagjes. Wanneer de wind een component heeft in de kijkrichting van de middelste microgolfbundel wordt de ene hoorn beschreven, en wanneer de wind een component heeft tegengesteld hieraan, de andere. Uit een trits metingen (met ruis) kan dus in het algemeen niet een unieke windvector worden bepaald. Twee ongeveer tegengestelde oplossingen resulteren. Deze dubbelzinnigheid in de windrichting kan in de praktijk worden opgelost door die oplossing te kiezen die het dichtst bij een korte termijn weervoorspelling ligt. Daarna kunnen eisen worden gesteld aan de ruimtelijke consistentie van het gevonden windvector veld. Zoals beschreven in hoofdstuk V levert zo'n methode de goede oplossing in meer dan 99 % van de gevallen. Zo kan een in het algemeen kwalitatief goed windproduct worden afgeleid uit de ERS scatterometermetingen. In het tweede gedeelte van hoofdstuk V wordt ingegaan op de assimilatie van scatterometergegevens in weermodellen. Voor variationele gegevensassimilatie wordt een methode voorgesteld, waarbij de dubbelzinnige scatterometerwinden worden geassimileerd, en niet direct de terugstrooiingsmetingen. Dit vanwege het feit dat de onzekerheid in de interpretatie van de scatterometer, het best is uit te drukken als een fout in de wind. De projectie van deze fout op de microgolfmetingen is niet-lineair, en daarmee tamelijk moeilijk te verwerken binnen de context van meteorologische variationele gegevensassimilatie. Assimilatie van de dubbelzinnige wind daarentegen is tamelijk recht toe recht aan. De scatterometermetingen leiden tot een duidelijk betere analyse en korte-termijn voorspelling van het windveld boven zee. De bedekking is echter zodanig dat andere windwaarnemingen nog lang een zeer welkome aanvulling zullen zijn. Nieuwe Amerikaanse scatterometers met een grotere bedekking zijn in ontwikkeling (met name QuikSCAT en SeaWinds). Vanwege hun andere geometrie en golflengte is echter eerst ontwikkelwerk nodig om tot een gedegen interpretatie te komen. De in dit proefschrift beschreven methodologie kan een belangrijke rol spelen in de interpretatie van de gegevens van deze scatterometers. De volgende generatie Europese scatterometers (ASCAT genoemd) heeft een?SAMENVATTING xi grote bedekking en de microgolflengte en meetgeometrie van de ERS scatterometers. Hiermee zijn we op termijn verzekerd van een goed scatterometer wind product.?SAMENVATTING xii

A revision of the tribe Planitorini van Achterberg (Hymenoptera, Braconidae, Euphorinae), with description of a new genus from Australia.

PubMed

van Achterberg, Cornelis; Quicke, Donald L J; Boring, C Andrew

2017-01-01

The tribe Planitorini van Achterberg (Hymenoptera: Braconidae: Euphorinae) is revised. One new genus Paramannokeraia gen. n. (type species: P. gibsoni sp. n. ) and five new species from Australia are described and illustrated: Mannokeraia albipalpis van Achterberg, sp. n. , M. nigrita van Achterberg, sp. n. , M. punctata van Achterberg, sp. n. , Paramannokeraia gibsoni van Achterberg & Quicke, sp. n. and P. juliae van Achterberg, sp. n. The tribe Mannokeraiini van Achterberg, 1995, is synonymized with the tribe Planitorini ( syn. n. ).

A revision of the tribe Planitorini van Achterberg (Hymenoptera, Braconidae, Euphorinae), with description of a new genus from Australia

PubMed Central

van Achterberg, Cornelis; Quicke, Donald L.J.; Boring, C. Andrew

2017-01-01

Abstract The tribe Planitorini van Achterberg (Hymenoptera: Braconidae: Euphorinae) is revised. One new genus Paramannokeraia gen. n. (type species: P. gibsoni sp. n.) and five new species from Australia are described and illustrated: Mannokeraia albipalpis van Achterberg, sp. n., M. nigrita van Achterberg, sp. n., M. punctata van Achterberg, sp. n., Paramannokeraia gibsoni van Achterberg & Quicke, sp. n. and P. juliae van Achterberg, sp. n. The tribe Mannokeraiini van Achterberg, 1995, is synonymized with the tribe Planitorini (syn. n.). PMID:29290713

Consequences of the Introduction of Insensitive Munitions on Safety, Collateral Damage and Operations (consequenties van de invoering van mkm-munitie op veiligheid, gevolgschade en (internationaal) opereren

DTIC Science & Technology

2006-06-01

van de werkzaamheden In dit rapport worden de gevolgen van initiatie van munitie door een ongewilde externe stimulus beschouwd aan de hand van reele...operationele scenario’s. Dit wordt vergeleken met de gevolgen in dezelfde scenario’s, waarin gebruik is gemaakt van Minder Kwetsbare Munitie (MKM). Naast...de historie van MKM wordt uitgelegd wat Inleiding of terroristische activiteiten, maar ook door MKM is. Vervolgens worden de gevolgen Munitie en de

Genomic and expression analysis of the vanG-like gene cluster of Clostridium difficile.

PubMed

Peltier, Johann; Courtin, Pascal; El Meouche, Imane; Catel-Ferreira, Manuella; Chapot-Chartier, Marie-Pierre; Lemée, Ludovic; Pons, Jean-Louis

2013-07-01

Primary antibiotic treatment of Clostridium difficile intestinal diseases requires metronidazole or vancomycin therapy. A cluster of genes homologous to enterococcal glycopeptides resistance vanG genes was found in the genome of C. difficile 630, although this strain remains sensitive to vancomycin. This vanG-like gene cluster was found to consist of five ORFs: the regulatory region consisting of vanR and vanS and the effector region consisting of vanG, vanXY and vanT. We found that 57 out of 83 C. difficile strains, representative of the main lineages of the species, harbour this vanG-like cluster. The cluster is expressed as an operon and, when present, is found at the same genomic location in all strains. The vanG, vanXY and vanT homologues in C. difficile 630 are co-transcribed and expressed to a low level throughout the growth phases in the absence of vancomycin. Conversely, the expression of these genes is strongly induced in the presence of subinhibitory concentrations of vancomycin, indicating that the vanG-like operon is functional at the transcriptional level in C. difficile. Hydrophilic interaction liquid chromatography (HILIC-HPLC) and MS analysis of cytoplasmic peptidoglycan precursors of C. difficile 630 grown without vancomycin revealed the exclusive presence of a UDP-MurNAc-pentapeptide with an alanine at the C terminus. UDP-MurNAc-pentapeptide [d-Ala] was also the only peptidoglycan precursor detected in C. difficile grown in the presence of vancomycin, corroborating the lack of vancomycin resistance. Peptidoglycan structures of a vanG-like mutant strain and of a strain lacking the vanG-like cluster did not differ from the C. difficile 630 strain, indicating that the vanG-like cluster also has no impact on cell-wall composition.

Inelastic processes in atomic collisions involving ground state and laser-prepared atoms

NASA Astrophysics Data System (ADS)

Planje, Willem Gilles

1999-11-01

In dit proefschrift worden experimenten beschreven waarbij ionen of atomen met een bepaalde snelheid op een ensemble van doelwitatomen worden gericht. Wanneer twee deeltjes elkaar voldoende genaderd hebben, vindt er wissel- werking plaats waarbij allerlei processen kunnen optreden. Deze processen resulteren in specieke eindproducten. Kennis over de interactie tussen twee botsingspartners wordt verkregen door te bekijken welke eindproducten ontstaan, en in welke mate. Een belangrijke grootheid die van invloed is op mogelijke processen is de onderlinge snelheid van de twee kernen, oftewel de botsingssnelheid. Wanneer de botsingssnelheid voldoende klein is dan kunnen de verschillende reactiemechanismen zowel kwalitatief als kwanti- tatief vaak goed voorspeld worden door het systeem te beschouwen als een kort-stondig molecuul, opgebouwd uit de twee botsende deeltjes. De ver- schillende processen die kunnen optreden worden gekwaliceerd afhankelijk van de vorming van bepaalde eindproducten. Ruwweg de volgende indeling kan gemaakt worden: 1. de interne structuur van de eindproducten zijn identiek aan die van de beginproducten. We spreken dan van een elastische botsing. 2. e en van de deeltjes of beiden worden in een aangeslagen toestand ge- bracht (of ge¨oniseerd). Dit zijn processen waarbij de herschikte elek- tronen zich bij de oorspronkelijke kern bevinden. We spreken dan van excitatie of ionisatie. 3. e en of meerdere elektronen bevinden zich bij de andere kern na de botsing (eventueel in aangeslagen toestand). We spreken dan van elek- tronenoverdracht. In het eerste deel van deze dissertatie worden botsingsexperimenten tussen heliumionen en natriumatomen beschreven waarbij het proces van elek- tronenoverdracht wordt onderzocht. Bij dit mechanisme is het buitenste 117?Samenvatting natriumelektron betrokken. Deze kan relatief gemakkelijk `overspringen' naar het heliumion wanneer deze zich dicht in de buurt van het natrium- atoom bevindt. Het elektron kan hierbij een bepaalde (aangeslagen) toe- stand bezetten. Wij meten de bezetting van de heliumtoestanden die onder uitzending van XUV licht ( ? 58 nm) vervallen naar de heliumgrondtoe- stand. Door de lichtintensiteit te meten onderzoeken we de mate van elek- tronenoverdracht naar een selecte groep van singlet helium`eind'toestanden, namelijk He(1s2p), He(1s3s), He(1s3p) en He(1s3d). In een reactie- vergelijking ziet het mechanisme er als volgt uit: He + (1s) + ( Na(3s) Na(3p) e- -! He + Na + -! He(1s 2 ) +h(58 nm) + Na + Het experiment kent een extra dimensie door het feit dat het, in beginsel bol- symmetrische, natriumatoom een bepaalde ruimtelijk uitlijning kan worden meegegeven. Met behulp van laserlicht van een specieke frequentie en po- larisatie, wordt het buitenste natriumelektron in een aangeslagen p toestand gebracht. Het aanslaan naar deze toestand heeft als gevolg dat het valentie- elektron zich op grotere afstand van zijn kern bevindt dan voorheen. Daar- naast kan, afhankelijk van de gebruikte laserpolarisatie, het buitenste elek- tron zich nu rond de natriumkern bewegen volgens een bepaalde anisotrope verdeling, de bolsymmetrie is doorbroken. De eecten van de excitatie en ruimtelijk verdeling van dit natriumelektron op het proces van elektronen- overdracht zijn onderzocht voor botsingsenergie¨en vari¨erend van 0.5 keV tot 6.0 keV. De metingen laten zien dat het eect van laserexcitatie een bezettingstoe- name van de beschouwde singlet heliumtoestanden betekent, ongeacht de uitlijning van het natrium 3p elektron. Dit is simpelweg te begrijpen uit het feit dat het 3p natrium elektron minder sterk gebonden is en elektro- nenoverdracht makkelijker gaat. Daarnaast is de uitlijning van het aanges- lagen elektron van invloed op de elektronenoverdracht. De resultaten zijn vergeleken met berekeningen van S.E. Nielsen en T.H. Rod [13], die de elek- tronoverdracht beschrijven in een model waarbij het betrokken elektron zich beweegt in bepaalde eectieve potentiaalvelden. De goede overeenkomsten van onze metingen met de berekeningen rechtvaardigen de theoretische be- nadering van Nielsen en Rod. 118?Samenvatting In het tweede gedeelte van het proefschrift worden botsingen beschouwd tussen helium- en neonatomen. Hierbij wordt nu niet gekeken naar bots- ingsproducten die zich manifesteren door bepaald licht uit te zenden, maar een elektron emitteren met een bepaalde energie. Verschillende soorten `eind'producten kunnen elektronen uitzenden, waaronder de negatieve ion- toestanden. Het elektronenspectrum, gemeten voor dit botsingssysteem, vertoont twee pieken die het spectrum domineren bij 16.2 eV en 19.4 eV voor verschillende botsingsenergie¨en tussen de 0.35 keV en 6.0 keV. Deze piekstructuren wijzen op de vorming van de kort-levende, negatieve iontoe- standen Ne-(2p 5 3s 2 ) en He-(1s2s 2 ) ten gevolge van de overdracht van e en elektron: He 0 + Ne 0 -! He-(1s2s 2 ) +Ne + (2p 5 ) 3 10- 14 s -! He 0 (1s 2 ) +Ne + + e- (19.37 eV) He 0 + Ne 0 -! He + (1s) +Ne-(2p 5 3s 2 ) 2:5 10- 13 s -! He + (1s) +Ne 0 (2p 6 ) +e- (16.15 eV) De meetresultaten vertonen een fenomeen waarbij de bezettingen van de negatieve iontoestanden een oscillerend gedrag vertonen als functie van de botsingssnelheid. Dit duidt op interferentie tussen de twee bijna-ontaarde moleculaire toestanden [He- + Ne + ] en[He + + Ne-]. Het is echter zeer op- merkelijk dat deze oscillatie wordt waargenomen in een experiment als deze, waarin de uitgezonden elektronen worden gemeten ongeacht de afbuighoek van het heliumatoom. Dit impliceert een speciek aanslagmechanisme van de moleculaire negatieve iontoestanden. Nader beschouwing van het bots- ingssysteem laat zien dat het instantane molecuul twee overgangen moet ondergaan voordat de negatieve iontoestanden gevormd worden. Als gevolg hiervan is de snelheid waarmee het negatieve en positieve ion uit elkaar be- wegen nagenoeg onafhankelijk van de afbuighoek van het helium projectiel en is oscillatie mogelijk waarneembaar. De wisselwerking tussen de twee beschouwde moleculaire toestanden impliceert gecorreleerde overdracht van twee elektronen: He- + Ne + 2e- ! He + + Ne- Door het quasi-resonante systeem als resonant te beschouwen kan het fenomeen kwalitatief goed verklaard worden. 119?Samenvatting Inhet laatstedeelwordt de bevolkingvanauto¨oniserende natriumtoestanden bekeken in He +=0 + Na botsingen. In tegenstelling tot de voorgaande exper- imenten waarin elektronenoverdracht beschouwd werd, betreft het hier een excitatiemechanisme. De beschouwde `eind'producten, i.e. de auto¨oniserende natriumtoestanden, bestaan in het algemeen kort en gaan over naar een stabiele iontoestand onder uitzending van een elektron met een toestands- karakteristieke kinetische energie. Door de elektronenspectra te meten bij verschillende botsingsenergie¨en, wordt de bezetting van de auto¨oniserende toestanden onderzocht. Ook hier wordt het eect van laserexcitatie en laser- polarisatie van het natriumatoom op de vorming van deze toestanden, en de mate waarin, bekeken. De metingen laten zien dat zowel in He + -Na als in He 0 -Na botsingen de invloed van de ruimtelijk uitlijning van het buitenste natriumelektron op de elektronenspectra nihil is. Dit impliceert dat het betrokken 3p elektron hoofdzakelijk een passieve rol speelt in de vorming van auto¨oniserende toe- standen: het blijft hoofdzakelijk de 3p toestand bezetten als een `toeschouwer' zonder een overgang te maken naar een andere toestand. Dit wordt boven- dien bevestigd door het feit dat wanneer een fractie natriumatomen aange- slagen wordt naar de p toestand dit een even grote reductie betekent van onder meer de populatie van de auto¨oniserende toestand Na(2p 5 3s 2 ). De verwachte grote toename van Na(2p 5 3p 2 ) toestanden, in geval van Na(3p) doelwitten, is niet waargenomen. 120?121?122

The first report of the vanC₁ gene in Enterococcus faecium isolated from a human clinical specimen.

PubMed

Sun, Mingyue; Wang, Yue; Chen, Zhongju; Zhu, Xuhui; Tian, Lei; Sun, Ziyong

2014-09-01

The vanC₁ gene, which is chromosomally located, confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Enterococcus faecium TJ4031 was isolated from a blood culture and harbours the vanC₁gene. Polymerase chain reaction (PCR) assays were performed to detect vanXYc and vanTc genes. Only the vanXYc gene was found in the E. faecium TJ4031 isolate. The minimum inhibitory concentrations of vancomycin and teicoplanin were 2 µg/mL and 1 µg/mL, respectively. Real-time reverse transcription-PCR results revealed that the vanC₁ and vanXYc genes were not expressed. Pulsed-field gel electrophoresis and southern hybridisation results showed that the vanC₁ gene was encoded in the chromosome. E. faecalis isolated from animals has been reported to harbour vanC₁gene. However, this study is the first to report the presence of the vanC₁gene in E. faecium of human origin. Additionally, our research showed the vanC₁gene cannot serve as a species-specific gene of E. gallinarum and that it is able to be transferred between bacteria. Although the resistance marker is not expressed in the strain, our results showed that E. faecium could acquire the vanC₁gene from different species.

Tweede Serie Ergonomietests Lichtgewicht Bommenpakken (Second Series of Ergonomic Tests on Lightweight Bomb Disposal Suits)

DTIC Science & Technology

2007-12-01

warmtebelastingtests vast te stellen en (sit-and-reach, stand-and-reach. abductie referentiewaarden te bepalen door het van de arnen, anteflexie van de armen ...volgende, bewegingbeperkingtests: sit-and-reach, stand-and-reach. abductie van de armen , anteflexie van de armen en beperking van zicht. Bij de sit-and...gebogen op de rand van een tafel en houdt de armen zo ver mogeijk gestrekt naar voren op tafel. Daarbij wordt de afstand vanaf de rand van de tafel tot

Molecular Characterization of Enterococcus faecalis N06-0364 with Low-Level Vancomycin Resistance Harboring a Novel d-Ala-d-Ser Gene Cluster, vanL▿

PubMed Central

Boyd, David A.; Willey, Barbara M.; Fawcett, Darlene; Gillani, Nazira; Mulvey, Michael R.

2008-01-01

Enterococcus faecalis N06-0364, exhibiting a vancomycin MIC of 8 μg/ml, was found to harbor a novel d-Ala-d-Ser gene cluster, designated vanL. The vanL gene cluster was similar in organization to the vanC operon, but the VanT serine racemase was encoded by two separate genes, vanTmL (membrane binding) and vanTrL (racemase). PMID:18458129

19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

Code of Federal Regulations, 2014 CFR

2014-04-01

... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2014-04-01 2014-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

Code of Federal Regulations, 2012 CFR

2012-04-01

... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2012-04-01 2012-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

19 CFR 10.41a - Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of international...

Code of Federal Regulations, 2013 CFR

2013-04-01

... for inspection by Customs officials upon reasonable notice. (3) If the container does not exit the U.S... 19 Customs Duties 1 2013-04-01 2013-04-01 false Lift vans, cargo vans, shipping tanks, skids... Traffic § 10.41a Lift vans, cargo vans, shipping tanks, skids, pallets, and similar instruments of...

First and Second Order Stokes Generation by SRS in Methane: Influence of Rep-Rate, Beam Quality and Astigmatism (Opwekking van Eerste en Tweede Orde Stokes d.m.v. SRS in Methaan: Invloed van de Pulsfrequentie, de Bundelkwaliteit en Astigmatisme)

DTIC Science & Technology

1992-09-01

omzettings rendementen van circa 75% gehaad bij een ingangs- energie van 280 mJ. De mogelijkheden tot bet halen van een hoger rendement lijken...of rep-rate, beam quality and astigmatism DImi-Thu-B~mO ITA1EiM-tT-h lF I~~ ~~’ IAPR2 8 1993~ I ~Xtbai Uiitdw FJ.M. van Putten J.C. van den Heuvel RJ.L...Influence of rep-rate. beam quality and astigmatism author(s) : F.J.M. van Putten, I.C. van den Heuvel, R.J.L. Lerou institute : TNO Physics and

Detailed geomorphological mapping of debris-covered and rock glaciers in the Hólar area, Tröllaskagi Peninsula (northern Iceland).

NASA Astrophysics Data System (ADS)

Tanarro, Luis M.; Palacios, David; Zamorano, Jose J.; Andres, Nuria

2017-04-01

Most studies conducted on rock and debris-covered glaciers only include simplified geomorphological maps representing main units (ridges, furrows, front, and thermokarst depressions). The aim of this study is to develop a detailed geomorphological mapping of the Hóladalsjökull debris-covered glacier (65°42' N; 18°57' W) and the Fremri-Grjótárdalur rock glacier (65°43' N 19° W), located near Hólar, a village in the central area of the Trolläskagi peninsula (northern Iceland). The mapping process has been conducted using standard stereo-photointerpretation of aerial photographs and stereo-plotting of a topographic map at 1:2000 scale. Also, landforms have been represented in different transects. Lastly, the geomorphological map has been designed using the elevation digital model, and a 3D pdf file has been generated, allowing for better viewing and understanding the different units and their modelling. The geomorphological mapping of the Hóladalsjökull debris-covered glacier and the Fremri-Grjótárdalur rock glacier represents the prominent walls of their valley heads and their summits, which form a flat highland at 1,200-1,330 metres above sea level, covered by blockfield and patterned ground features. Rockfall and slide landforms are common processes at the foot of these 100-170 metre-high cirque-walls. Debris-covered glaciers and rock glaciers are born right under these walls, building up a spoon-shaped hollow around glacial ice, surrounded by young moraine ridges at their fronts. The dominant features in the Hóladalsjökull debris-covered glacier are large longitudinal ridges and furrows, stretching over 1.5 km in length in the central and western areas. Medium-sized thermokarst depressions (between 15-40 metres in diameter), often running parallel to the furrows, dot the surface of the debris-covered glacier. Parallel alternate ridges and furrows can be seen near the snout. Ridges are rugged and fall around 30-40 metres, with over 30 degree slopes, whereas furrows have smoother hillsides. The snout of the debris-covered glacier is around 900 m high. Several units of rock glaciers from different overlapping ages can be distinguished in the Fremri-Grjótárdalur cirque. Deep and meandering furrows have developed in the contact areas between the main lobes. The lobes of the youngest rock glaciers, located at the cirque head, reach a length of between 0.5 km and 1 km. Their morphology changes from their rooting zone, with alternate smooth furrows and ridges extending towards their front, where steep ridges and furrows appear, and ends in a steep front between 896 and 922 m high. These rock glaciers overlap one another on a fossil rock glacier, rising another 400 m until they reach a height of 850 m. Research funded by Deglaciation project (CGL2015-65813-R), Government of Spain

Pollution from the 2014-15 Bárðarbunga eruption monitored by snow cores from the Vatnajökull glacier, Iceland

NASA Astrophysics Data System (ADS)

Galeczka, Iwona; Eiriksdottir, Eydis Salome; Pálsson, Finnur; Oelkers, Eric; Lutz, Stefanie; Benning, Liane G.; Stefánsson, Andri; Kjartansdóttir, Ríkey; Gunnarsson-Robin, Jóhann; Ono, Shuhei; Ólafsdóttir, Rósa; Jónasdóttir, Elín Björk; Gislason, Sigurdur R.

2017-11-01

The chemical composition of Icelandic rain and snow is dominated by marine aerosols, however human and volcanic activity can also affect these compositions. The six month long 2014-15 Bárðarbunga volcanic eruption was the largest in Iceland for more than 200 years and it released into the atmosphere an average of 60 kt/day SO2, 30 kt/day CO2, 500 t/day HCl and 280 t/day HF. To study the effect of this eruption on the winter precipitation, snow cores were collected from the Vatnajökull glacier and the highlands northeast of the glacier. In addition to 29 bulk snow cores from that precipitated from September 2014 until March 2015, two cores were sampled in 21 and 44 increments to quantify the spatial and time evolution of the chemical composition of the snow. The pH and chemical compositions of melted snow samples indicate that snow has been affected by the volcanic gases emitted during the Bárðarbunga eruption. The pH of the melted bulk snow cores ranged from 4.41 to 5.64 with an average value of 5.01. This is four times greater H+ activity than pure water saturated with the atmospheric CO2. The highest concentrations of volatiles in the snow cores were found close to the eruption site as predicted from CALPUFF SO2 gas dispersion quality model. The anion concentrations (SO4, Cl, and F) were higher and the pH was lower compared to equivalent snow samples collected during 1997-2006 from the unpolluted Icelandic Langjökull glacier. Higher SO4 and Cl concentrations in the snow compared with the unpolluted rainwater of marine origin confirm the addition of a non-seawater SO4 and Cl. The δ34S isotopic composition confirms that the sulphur addition is of volcanic aerosol origin. The chemical evolution of the snow with depth reflects changes in the lava effusion and gas emission rates. Those rates were the highest at the early stage of the eruption. Snow that fell during that time, represented by samples from the deepest part of the snow cores, had the lowest pH and highest concentrations of SO4, F, Cl and metals, compared with snow that fell later in the winter. Also the Al concentration, did exceed World Health Organisation drinking water standard of 3.7 μmol/kg in the lower part of the snow core closest to the eruption site. Collected snow represents the precipitation that fell during the eruption period. Nevertheless, only minor environmental impacts are evident in the snow due to its interaction with the volcanic aerosol gases. In addition, the microbial communities identified in the snow that fell during the eruption were similar to those found in snow from other parts of the Arctic, confirming an insignificant impact of this eruption on the snow microecology.

Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin

PubMed Central

Phillips-Jones, Mary K.; Channell, Guy; Kelsall, Claire J.; Hughes, Charlotte S.; Ashcroft, Alison E.; Patching, Simon G.; Dinu, Vlad; Gillis, Richard B.; Adams, Gary G.; Harding, Stephen E.

2017-01-01

VanA-type resistance to glycopeptide antibiotics in clinical enterococci is regulated by the VanSARA two-component signal transduction system. The nature of the molecular ligand that is recognised by the VanSA sensory component has not hitherto been identified. Here we employ purified, intact and active VanSA membrane protein (henceforth referred to as VanS) in analytical ultracentrifugation experiments to study VanS oligomeric state and conformation in the absence and presence of vancomycin. A combination of sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge (SEDFIT, SEDFIT-MSTAR and MULTISIG analysis) showed that VanS in the absence of the ligand is almost entirely monomeric (molar mass M = 45.7 kDa) in dilute aqueous solution with a trace amount of high molar mass material (M ~ 200 kDa). The sedimentation coefficient s suggests the monomer adopts an extended conformation in aqueous solution with an equivalent aspect ratio of ~(12 ± 2). In the presence of vancomycin over a 33% increase in the sedimentation coefficient is observed with the appearance of additional higher s components, demonstrating an interaction, an observation consistent with our circular dichroism measurements. The two possible causes of this increase in s – either a ligand induced dimerization and/or compaction of the monomer are considered. PMID:28397853

In Vivo Fluorescence Confocal Microscopy to Investigate the Role of RhoC in Inflammatory Breast Cancer

DTIC Science & Technology

2005-04-01

5084. 6. Colpaert CG, Vermeulen PB, Benoy I, Soubry A, van Roy F, van Beest P, Goovaerts G, Dirix LY, van Dam P, Fox SB, Harris AL, van MarckEA...cancer. Cancer Res 1999, 59: 5079-5084. 17 14. Colpaert CG, Vermeulen PB, Benoy I, Soubry A, van Roy F, van Beest P, Goovaerts G, Dirix LY, van Dam P...Ohira S, Feng Y, Nikaido T, Konishi I: Up- regulation of small GTPases, RhoA and RhoC, is associated with tumor progression in ovarian carcinoma. Lab

Mentale Inzetbaarheid van Teams: Ontwikkeling van een Moden van Teamfunctioneren als Module voor SCOPE (Mental Readiness of Teams - Development of a Team Model as Module for SCOPE)

DTIC Science & Technology

2007-04-01

inzetbaarheid van teams: ontwikkeling van een model van teamfunctioneren als module voor SCOPE Datumn april 2007 Auteur (s) R. de B~ruin C’. Vervvijs A.J...Datum april 2007 Programmaleider Projectleider Auteur (s) dr. W.A. Lotens, TNO Defensie en A.]. van Vijet, TNO Defensie en R. de Bruin Veiligheid...Deelnemers verwachten wel, in lijn met de theorie , dat een lage cohesie samenhangt met een lage effectiviteit. Een hoge cohesie, daarentegen, zou

User Manual PIRATE Model, Release Beta 1.0. (Handleiding PIRATE model, versie Beta 1.0)

DTIC Science & Technology

1998-01-01

Beperkingen van PIRATE 40 9 . Conclusies en aanbevelingen 41 10. Referenties 42 11 . Ondertekening 43 TNO-rapport FEL-97-A285 Inleiding Bij maritieme...Inhoud Inleiding 7 1.1 Doel van PIRATE 7 1.2 Werking van PIRATE 8 1.3 Opbouw van de handleiding 8 2. Bediening van PIRATE 9 2.1 Systeemvereisten 10...2.2 Installatie 10 2.3 Bediening van de gebruikersinterface 11 2.4 Gebruiken van de figuren in andere programmes 15 3. Radars, radars in PIRATE

Symmetry operators of Killing spinors and superalgebras in AdS5

NASA Astrophysics Data System (ADS)

Ertem, Ümit

2016-04-01

We construct the first-order symmetry operators of Killing spinor equation in terms of odd Killing-Yano forms. By modifying the Schouten-Nijenhuis bracket of Killing-Yano forms, we show that the symmetry operators of Killing spinors close into an algebra in AdS5 spacetime. Since the symmetry operator algebra of Killing spinors corresponds to a Jacobi identity in extended Killing superalgebras, we investigate the possible extensions of Killing superalgebras to include higher-degree Killing-Yano forms. We found that there is a superalgebra extension but no Lie superalgebra extension of the Killing superalgebra constructed out of Killing spinors and odd Killing-Yano forms in AdS5 background.

Molecular epidemiology of vancomycin resistant enterococci in a tertiary care hospital in Saudi Arabia.

PubMed

Somily, Ali M; Al-Mohizea, Maha M; Absar, Muhammed M; Fatani, Amal J; Ridha, Afaaf M; Al-Ahdal, Mohammed N; Senok, Abiola C; Al-Qahtani, Ahmed A

2016-08-01

Vancomycin-resistant enterococci (VRE) are a major cause of nosocomial infections with high mortality and morbidity. There is limited data on the molecular characterization of VRE in Saudi Arabia. This study was carried out to investigate the premise that a shift in VRE epidemiology is occurring in our setting. Enterococcus species identification and susceptibility testing plus VRE phenotypic confirmation by vancomycin and teicoplanin E-test were carried out. Vancomycin resistance genes were detected by PCR. Strain typing was conducted using PFGE. Among the strains of Enterococcus spp. investigated in this study, 17 (4.5%) were VRE. With the exception of one isolate from rectal swab, all others were clinical specimens with blood being the commonest source (n = 11; 64.7%), followed by urine (n = 3; 17.6%). The 17 VRE isolates were Enterococcus faecium (n/N = 13/17) and Enterococcus gallinarum (n/N = 4/17). Among E. faecium isolates, vanA(+)/vanB(+) (n/N = 8/13; 62%) exhibiting VanB phenotype were predominant. One of the five vanA(+)E. faecium isolates exhibited a VanB phenotype indicative of vanA genotype-VanB phenotype incongruence. E. gallinarum isolates exhibited a Van C phenotype although two were vanA(+)/vanC1(+). PFGE revealed a polyclonal distribution with eight pulsotypes. These findings indicate an evolving VRE epidemiology with vanA(+)/vanB(+) isolates and vanA genotype-VanB phenotype incongruence isolates, which were previously described as colonizers, are now causing clinical infection. Copyright © 2016 Elsevier Ltd. All rights reserved.

RpoS induces expression of the Vibrio anguillarum quorum-sensing regulator VanT.

PubMed

Weber, Barbara; Croxatto, Antony; Chen, Chang; Milton, Debra L

2008-03-01

In vibrios, regulation of the Vibrio harveyi-like LuxR transcriptional activators occurs post-transcriptionally via small regulatory RNAs (sRNAs) that destabilize the luxR mRNA at a low cell population, eliminating expression of LuxR. Expression of the sRNAs is modulated by the vibrio quorum-sensing phosphorelay systems. However, vanT mRNA, which encodes a LuxR homologue in Vibrio anguillarum, is abundant at low and high cell density, indicating that VanT expression may be regulated via additional mechanisms. In this study, Western analyses showed that VanT was expressed throughout growth with a peak of expression during late exponential growth. VanO induced partial destabilization of vanT mRNA via activation of at least one Qrr sRNA. Interestingly, the sigma factor RpoS significantly stabilized vanT mRNA and induced VanT expression during late exponential growth. This induction was in part due to RpoS repressing expression of Hfq, an RNA chaperone. RpoS is not part of the quorum-sensing regulatory cascade since RpoS did not regulate expression or activity of VanO, and RpoS was not regulated by VanO or VanT. VanT and RpoS were needed for survival following UV irradiation and for pigment and metalloprotease production, suggesting that RpoS works with the quorum-sensing systems to modulate expression of VanT, which regulates survival and stress responses.

Chlorhexidine Induces VanA-Type Vancomycin Resistance Genes in Enterococci

PubMed Central

Bhardwaj, Pooja; Ziegler, Elizabeth

2016-01-01

Chlorhexidine is a bisbiguanide antiseptic used for infection control. Vancomycin-resistant E. faecium (VREfm) is among the leading causes of hospital-acquired infections. VREfm may be exposed to chlorhexidine at supra- and subinhibitory concentrations as a result of chlorhexidine bathing and chlorhexidine-impregnated central venous catheter use. We used RNA sequencing to investigate how VREfm responds to chlorhexidine gluconate exposure. Among the 35 genes upregulated ≥10-fold after 15 min of exposure to the MIC of chlorhexidine gluconate were those encoding VanA-type vancomycin resistance (vanHAX) and those associated with reduced daptomycin susceptibility (liaXYZ). We confirmed that vanA upregulation was not strain or species specific by querying other VanA-type VRE. VanB-type genes were not induced. The vanH promoter was found to be responsive to subinhibitory chlorhexidine gluconate in VREfm, as was production of the VanX protein. Using vanH reporter experiments with Bacillus subtilis and deletion analysis in VREfm, we found that this phenomenon is VanR dependent. Deletion of vanR did not result in increased chlorhexidine susceptibility, demonstrating that vanHAX induction is not protective against chlorhexidine. As expected, VanA-type VRE is more susceptible to ceftriaxone in the presence of sub-MIC chlorhexidine. Unexpectedly, VREfm is also more susceptible to vancomycin in the presence of subinhibitory chlorhexidine, suggesting that chlorhexidine-induced gene expression changes lead to additional alterations in cell wall synthesis. We conclude that chlorhexidine induces expression of VanA-type vancomycin resistance genes and genes associated with daptomycin nonsusceptibility. Overall, our results indicate that the impacts of subinhibitory chlorhexidine exposure on hospital-associated pathogens should be further investigated in laboratory studies. PMID:26810654

Tussenrapportage Validatie Onderwijsvernieuwingen (Validation Assistant in Instructional Design)

DTIC Science & Technology

2007-05-01

validatie onderwij svemieuwingen D)atum mei 2007 Auteur (s) drs. J.P. van Meer drs. G,J. Veldhuis dr. M.L. van Ernmerik M.G. van Schaik Rubricering...als doel om nog beter is het van belang dat het maken van keuzes Auteur (s) passende adviezen te kunnen genereren. binnen een moeilijk grijpbaar...benaderd door de theorie achter de onderwijsconcepten te toetsen aan het oordeel van de expert. Er zijn echter beperkingen in deze opzet denkbaar die

Emergence of vanA Enterococcus faecium in Denmark, 2005-15.

PubMed

Hammerum, Anette M; Baig, Sharmin; Kamel, Yasmin; Roer, Louise; Pinholt, Mette; Gumpert, Heidi; Holzknecht, Barbara; Røder, Bent; Justesen, Ulrik S; Samulioniené, Jurgita; Kjærsgaard, Mona; Østergaard, Claus; Holm, Anette; Dzajic, Esad; Søndergaard, Turid Snekloth; Gaini, Shahin; Edquist, Petra; Alm, Erik; Lilje, Berit; Westh, Henrik; Stegger, Marc; Hasman, Henrik

2017-08-01

To describe the changing epidemiology of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis in clinical samples in Denmark 2005-15 according to species and van type, and, furthermore, to investigate the genetic relatedness of the clinical E. faecium isolates from 2015. During 2005-14, all clinical VRE isolates were tested for the presence of vanA/B/C genes by PCR. In 2015, all clinical VRE isolates were whole-genome sequenced. From the WGS data, the presence of van genes and MLST STs were extracted in silico . Core-genome MLST (cgMLST) analysis was performed for the vancomycin-resistant E. faecium isolates. During 2005-15, 1043 vanA E. faecium , 25 vanB E. faecium , 4 vanA E. faecalis and 28 vanB E. faecalis were detected. The number of VRE was <50 isolates/year until 2012 to > 200 isolates/year in 2013-15. In 2015, 368 vanA E. faecium and 1 vanB E. faecium were detected along with 1 vanA E. faecalis and 1 vanB E. faecalis . cgMLST subdivided the 368 vanA E. faecium isolates into 33 cluster types (CTs), whereas the vanB E. faecium isolate belonged to a different CT. ST203-CT859 was most prevalent (51%), followed by ST80-CT14 (22%), ST117-CT24 (6%), ST80-CT866 (4%) and ST80-CT860 (2%). Comparison with the cgMLST.org database, previous studies and personal communications with neighbouring countries revealed that the novel cluster ST203-CT859 emerged in December 2014 and spread to the south of Sweden and the Faroe Islands during 2015. VRE increased in Denmark during 2005-15 due to the emergence of several vanA E. faecium clones. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Vancomycin-resistance phenotypes, vancomycin-resistance genes, and resistance to antibiotics of enterococci isolated from food of animal origin.

PubMed

Gousia, Panagiota; Economou, Vangelis; Bozidis, Petros; Papadopoulou, Chrissanthy

2015-03-01

In the present study, 500 raw beef, pork, and chicken meat samples and 100 pooled egg samples were analyzed for the presence of vancomycin-resistant enterococci, vancomycin-resistance phenotypes, and resistance genes. Of 141 isolates of enterococci, 88 strains of Enterococcus faecium and 53 strains of E. faecalis were identified. The most prevalent species was E. faecium. Resistance to ampicillin (n = 93, 66%), ciprofloxacin (n = 74, 52.5%), erythromycin (n = 73, 51.8%), penicillin (n = 59, 41.8%) and tetracycline (n = 52, 36.9%) was observed, while 53.2% (n = 75) of the isolates were multiresistant and 15.6% (n = 22) were susceptible to all antibiotics. Resistance to vancomycin was exhibited in 34.1% (n = 30) of the E. faecium isolates (n = 88) and 1.9% (n = 1) of the E. faecalis isolates (n = 53) using the disc-diffusion test and the E-test. All isolates were tested for vanA and vanB using real-time polymerase chain reaction (PCR) and multiplex PCR, and for vanC, vanD, vanE, vanG genes using multiplex PCR only. Among E. faecalis isolates, no resistance genes were identified. Among the E. faecium isolates, 28 carried the vanA gene when tested by multiplex PCR and 29 when tested with real-time PCR. No isolate carrying the vanC, vanD, vanE, or vanG genes was identified. Melting-curve analysis of the positive real-time PCR E. faecium isolates showed that 22 isolates carried the vanA gene only, 2 isolates the vanB2,3 genes only, and seven isolates carried both the vanA and vanB2,3 genes. Enterococci should be considered a significant zoonotic pathogen and a possible reservoir of genes encoding resistance potentially transferred to other bacterial species.

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements apply to all bridges across Newtown Creek, Dutch Kills, English Kills, and their tributaries: (1) The...

Wind and Current Forces Acting on Canadian Forces Ships During Tug Operations

DTIC Science & Technology

2002-11-01

McTaggart and Sav- age [1] describe model tests conducted on a generic frigate model to determine wind forces influencing ship capsize. Van Manen and van ...Fn will be 0.06. Based on data presented by van Manen and van Oossanen [2], the fric- tional resistance coefficient will be approximately 0.002 and...Conference on Stability of Ships and Ocean Vehicles (Melbourne, Florida, 1994). 2. J.D. van Manen and P. van Oossanen, Principles of Naval Architecture, Volume

Softwaremodule voor het Simuleren van de Gevolgen van Raketonderschepping (The Dutch Program for the Simulation of Missile Intercept Effects)

DTIC Science & Technology

2007-07-01

effects (Softwaremodule voor het simuleren van de gevolgen van raketonderschepping) 11 . AUTHOR(S) Dr E. Abadjieva, MSc R.P. Sterkenburg, MSc F. Bouquet...Softwaremnodule voor het simuleren van de gevolgen van raketonderschepping D)attini Juli 2007 Auteur(s) dr. F. Abadjicva ir. R.P Sterkenburg ir. F. Bouquet ir...P.W. D)ouip Rubricering rapport O)ngerubri ceerd Vastgesteld door Maj R. 11 . Jongkinid Vastgesteld d.d. 12 juni 2007 (Deze nitining mizil-4 sict

Killing-Yano tensors in spaces admitting a hypersurface orthogonal Killing vector

NASA Astrophysics Data System (ADS)

Garfinkle, David; Glass, E. N.

2013-03-01

Methods are presented for finding Killing-Yano tensors, conformal Killing-Yano tensors, and conformal Killing vectors in spacetimes with a hypersurface orthogonal Killing vector. These methods are similar to a method developed by the authors for finding Killing tensors. In all cases one decomposes both the tensor and the equation it satisfies into pieces along the Killing vector and pieces orthogonal to the Killing vector. Solving the separate equations that result from this decomposition requires less computing than integrating the original equation. In each case, examples are given to illustrate the method.

Integrability conditions for Killing-Yano tensors and conformal Killing-Yano tensors

NASA Astrophysics Data System (ADS)

Batista, Carlos

2015-01-01

The integrability conditions for the existence of a conformal Killing-Yano tensor of arbitrary order are worked out in all dimensions and expressed in terms of the Weyl tensor. As a consequence, the integrability conditions for the existence of a Killing-Yano tensor are also obtained. By means of such conditions, it is shown that in certain Einstein spaces one can use a conformal Killing-Yano tensor of order p to generate a Killing-Yano tensor of order (p -1 ) . Finally, it is proved that in maximally symmetric spaces the covariant derivative of a Killing-Yano tensor is a closed conformal Killing-Yano tensor and that every conformal Killing-Yano tensor is uniquely decomposed as the sum of a Killing-Yano tensor and a closed conformal Killing-Yano tensor.

Glucagon-like peptide-1 regulates brown adipose tissue thermogenesis via the gut-brain axis in rats.

PubMed

Krieger, Jean-Philippe; Santos da Conceição, Ellen Paula; Sanchez-Watts, Graciela; Arnold, Myrtha; Pettersen, Klaus G; Mohammed, Mazher; Modica, Salvatore; Lossel, Pius; Morrison, Shaun F; Madden, Christopher J; Watts, Alan G; Langhans, Wolfgang; Lee, Shin J

2018-05-30

Endogenous intestinal glucagon-like peptide-1 (GLP-1) controls satiation and glucose metabolism via vagal afferent neurons (VAN). Recently, VAN have received increasing attention for their role in brown adipose tissue (BAT) thermogenesis. It is however unclear whether VAN GLP-1 receptor (GLP-1R) signaling affects BAT thermogenesis and energy expenditure (EE), and whether this VAN mechanism contributes to energy balance. First, we tested the effect of the GLP-1R agonist Exendin-4 (Ex4, 0.3 μg/kg IP) on EE and BAT thermogenesis, and whether these effects require VAN GLP-1R signaling, using a rat model with a selective Glp1r knockdown (kd) in VAN. Second, we examined the role of VAN GLP-1R in energy balance during chronic high-fat diet (HFD) feeding in VAN Glp1r kd rats. Lastly, we used viral transsynaptic tracers to identify the possible neuronal substrates of such a gut-BAT interaction. VAN Glp1r kd attenuated the acute suppressive effects of Ex4 on EE and BAT thermogenesis. Consistent with this finding, the VAN Glp1r kd increased EE and BAT activity, diminished body weight gain, and improved insulin sensitivity compared to HFD-fed controls. Anterograde transsynaptic viral tracing of VAN infected major hypothalamic and hindbrain areas involved in BAT sympathetic regulation. Moreover, retrograde tracing from BAT combined with laser capture microdissection revealed that a population of VAN expressing Glp1r is synaptically connected to the BAT. Our findings reveal a novel role of VAN GLP-1R signaling in the regulation of EE and BAT thermogenesis, and imply that through this gut-brain-BAT connection intestinal GLP-1 plays a role in HFD-induced metabolic syndrome.

Evaluatie Kennistechnologische Ondersteuning bij Diagnose van SEWACO systemen (Projectmanagementplan) (Evaluation of Knowledge Technological Support for Diagnosis of SEWACO Systems (Project Management Plan)

DTIC Science & Technology

1991-08-01

diagnos van SE WACO systmnen/ AD-A245 424111 1fl1,l Niets uit deze uitgave mag warden vermenigvuldligd en/of oPenbaar gemaakt door middel van druk...fotakopie. microfilm of op welks andere whlze dan ook, zonder voorafgaande toeslemming van TNO. Hot ter inzage geven van het TNO-rapport aan direct...belanghebbenden is tegestaan. HYP. vanl OC dt Indian dit rapport in opdracht ward uitgebracht, wordt voor de, rechten en verpiichtingen van opdrachtgever en

Lie algebra of conformal Killing-Yano forms

NASA Astrophysics Data System (ADS)

Ertem, Ümit

2016-06-01

We provide a generalization of the Lie algebra of conformal Killing vector fields to conformal Killing-Yano forms. A new Lie bracket for conformal Killing-Yano forms that corresponds to slightly modified Schouten-Nijenhuis bracket of differential forms is proposed. We show that conformal Killing-Yano forms satisfy a graded Lie algebra in constant curvature manifolds. It is also proven that normal conformal Killing-Yano forms in Einstein manifolds also satisfy a graded Lie algebra. The constructed graded Lie algebras reduce to the graded Lie algebra of Killing-Yano forms and the Lie algebras of conformal Killing and Killing vector fields in special cases.

The phosphotransferase VanU represses expression of four qrr genes antagonizing VanO-mediated quorum-sensing regulation in Vibrio anguillarum

PubMed Central

Weber, Barbara; Lindell, Kristoffer; El Qaidi, Samir; Hjerde, Erik; Willassen, Nils-Peder

2011-01-01

Vibrio anguillarum utilizes quorum sensing to regulate stress responses required for survival in the aquatic environment. Like other Vibrio species, V. anguillarum contains the gene qrr1, which encodes the ancestral quorum regulatory RNA Qrr1, and phosphorelay quorum-sensing systems that modulate the expression of small regulatory RNAs (sRNAs) that destabilize mRNA encoding the transcriptional regulator VanT. In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by σ54 and the σ54-dependent response regulator VanO, and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilized vanT mRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all four qrr genes peaked at high cell density, and exogenously added N-acylhomoserine lactone molecules induced expression of the qrr genes at low cell density. The phosphotransferase VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilized vanT mRNA. A model is presented proposing that VanU acts as a branch point, aiding cross-regulation between two independent phosphorelay systems that activate or repress expression of the Qrr sRNAs, giving flexibility and precision in modulating VanT expression and inducing a quorum-sensing response to stresses found in a constantly changing aquatic environment. PMID:21948044

The phosphotransferase VanU represses expression of four qrr genes antagonizing VanO-mediated quorum-sensing regulation in Vibrio anguillarum.

PubMed

Weber, Barbara; Lindell, Kristoffer; El Qaidi, Samir; Hjerde, Erik; Willassen, Nils-Peder; Milton, Debra L

2011-12-01

Vibrio anguillarum utilizes quorum sensing to regulate stress responses required for survival in the aquatic environment. Like other Vibrio species, V. anguillarum contains the gene qrr1, which encodes the ancestral quorum regulatory RNA Qrr1, and phosphorelay quorum-sensing systems that modulate the expression of small regulatory RNAs (sRNAs) that destabilize mRNA encoding the transcriptional regulator VanT. In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by σ(54) and the σ(54)-dependent response regulator VanO, and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilized vanT mRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all four qrr genes peaked at high cell density, and exogenously added N-acylhomoserine lactone molecules induced expression of the qrr genes at low cell density. The phosphotransferase VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilized vanT mRNA. A model is presented proposing that VanU acts as a branch point, aiding cross-regulation between two independent phosphorelay systems that activate or repress expression of the Qrr sRNAs, giving flexibility and precision in modulating VanT expression and inducing a quorum-sensing response to stresses found in a constantly changing aquatic environment.

Review of Stantonia Ashmead (Hymenoptera, Braconidae, Orgilinae) from Vietnam, China, Japan, and Russia, with descriptions of six new species

PubMed Central

van Achterberg, Cornelis; Long, Khuat Dang; Chen, Xue-xin

2017-01-01

Abstract The genus Stantonia Ashmead, 1904 (Hymenoptera, Braconidae, Orgilinae) is reviewed for Vietnam, China, Japan, and Russia. Six new species of the genus Stantonia are described and illustrated: Stantonia brevicaudata van Achterberg, sp. n., S. dickyyui van Achterberg & Long, sp. n., S. granulata Long & van Achterberg, sp. n., S. robustifemur van Achterberg & Long, sp. n., S. stilpnosoma Long & van Achterberg, sp. n., and S. vietnamica van Achterberg, sp. n. A new subgenus (Planitonia subg. n.: type species Stantonia robustifemur van Achterberg & Long, sp. n.) is proposed for the species with a flat clypeus and face, and reduced vein r-m of the fore wing. Three species are newly recorded from Vietnam: Stantonia gracilis van Achterberg, 1987, S. sumatrana Enderlein, 1908, and S. tianmushana Chen, He & Ma, 2004. A key to species of Stantonia from Vietnam, China, Russia, and Japan is provided. PMID:29362527

Quantitative Characterization of Molecular Similarity Spaces: Tools for Computational Toxicology

DTIC Science & Technology

2000-01-20

numbers for hydrogen-filled molecular structure, hydrogen-suppressed molecular structure, and van der Waals volume. Van der Waals...relative covalent radii Geometrical Vw van der Waals volume 3DW 3-D Wiener number for the hydrogen-suppressed geometric distance matrix...molecular structure, and van der Waals volume. Van der Waals volume, Vw (Bondi 1964). was calculated using Sybyl 6.1 from Tripos As- sociates. Inc

Physical Protection: the State of the Art

DTIC Science & Technology

2005-02-01

fundamentele mechanisme van adsorptie van water beschrijft; dit is ingewikkeld en kost veel tijd ; een tweede benadering is het opstellen van een eenvoudig...gasscheidingsmethoden, bij voorkeur regeneratief, zijn zeer wenselijk vanwege de logistieke voordelen en de gegarandeerde langere operatie tijd . P(T)SA is meer...in de loop van de tijd ) met vrij simpele middelen en technieken sterk worden verbeterd. Deze technieken, zoals micro-encapsulatie en toevoeging van

Thickened boundary layer theory for air film drag reduction on a van body surface

NASA Astrophysics Data System (ADS)

Xie, Xiaopeng; Cao, Lifeng; Huang, Heng

2018-05-01

To elucidate drag reduction mechanism on a van body surface under air film condition, a thickened boundary layer theory was proposed and a frictional resistance calculation model of the van body surface was established. The frictional resistance on the van body surface was calculated with different parameters of air film thickness. In addition, the frictional resistance of the van body surface under the air film condition was analyzed by computational fluid dynamics (CFD) simulation and different air film states that influenced the friction resistance on the van body surface were discussed. As supported by the CFD simulation results, the thickened boundary layer theory may provide reference for practical application of air film drag reduction on a van body surface.

AUC/MIC Pharmacodynamic Target Is Not a Good Predictor of Vancomycin Efficacy in Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis

PubMed Central

Castañeda, Ximena; García-de-la-Mària, Cristina; Gasch, Oriol; Pericas, Juan M.; Armero, Yolanda; Soy, Dolors; García-González, Javier; Falces, Carlos; Ninot, Salvador; Almela, Manel; Ambrosioni, Juan; Quintana, Eduardo; Vidal, Barbara; Fuster, David; Llopis, Jaume; Soto, Sara; Moreno, Asuncion; Marco, Francesc

2017-01-01

ABSTRACT The aim of this in vivo study was to compare the efficacy of vancomycin at standard doses (VAN-SD) to that of VAN at adjusted doses (VAN-AD) in achieving a VAN area under the curve/MIC ratio (AUC/MIC) of ≥400 against three methicillin-resistant Staphylococcus aureus (MRSA) strains with different microdilution VAN MICs in an experimental endocarditis model. The valve vegetation bacterial counts after 48 h of VAN therapy were compared, and no differences were observed between the two treatment groups for any of the three strains tested. Overall, for VAN-SD and VAN-AD, the rates of sterile vegetations were 15/45 (33.3%) and 21/49 (42.8%) (P = 0.343), while the medians (interquartile ranges [IQRs]) for log10 CFU/g of vegetation were 2 (0 to 6.9) and 2 (0 to 4.5) (P = 0.384), respectively. In conclusion, this VAN AUC/MIC pharmacodynamic target was not a good predictor of vancomycin efficacy in MRSA experimental endocarditis. PMID:28373187

AUC/MIC Pharmacodynamic Target Is Not a Good Predictor of Vancomycin Efficacy in Methicillin-Resistant Staphylococcus aureus Experimental Endocarditis.

PubMed

Castañeda, Ximena; García-de-la-Mària, Cristina; Gasch, Oriol; Pericas, Juan M; Armero, Yolanda; Soy, Dolors; García-González, Javier; Falces, Carlos; Ninot, Salvador; Almela, Manel; Ambrosioni, Juan; Quintana, Eduardo; Vidal, Barbara; Fuster, David; Llopis, Jaume; Soto, Sara; Moreno, Asuncion; Marco, Francesc; Miró, Jose M

2017-06-01

The aim of this in vivo study was to compare the efficacy of vancomycin at standard doses (VAN-SD) to that of VAN at adjusted doses (VAN-AD) in achieving a VAN area under the curve/MIC ratio (AUC/MIC) of ≥400 against three methicillin-resistant Staphylococcus aureus (MRSA) strains with different microdilution VAN MICs in an experimental endocarditis model. The valve vegetation bacterial counts after 48 h of VAN therapy were compared, and no differences were observed between the two treatment groups for any of the three strains tested. Overall, for VAN-SD and VAN-AD, the rates of sterile vegetations were 15/45 (33.3%) and 21/49 (42.8%) ( P = 0.343), while the medians (interquartile ranges [IQRs]) for log 10 CFU/g of vegetation were 2 (0 to 6.9) and 2 (0 to 4.5) ( P = 0.384), respectively. In conclusion, this VAN AUC/MIC pharmacodynamic target was not a good predictor of vancomycin efficacy in MRSA experimental endocarditis. Copyright © 2017 American Society for Microbiology.

Transient aerodynamic characteristics of vans during the accelerated overtaking process

NASA Astrophysics Data System (ADS)

Liu, Li-ning; Wang, Xing-shen; Du, Guang-sheng; Liu, Zheng-gang; Lei, Li

2018-04-01

This paper studies the influence of the accelerated overtaking process on the vehicles' transient aerodynamic characteristics, through 3-D numerical simulations with dynamic meshes and sliding interface technique. Numerical accuracy is verified by experimental results. The aerodynamic characteristics of vehicles in the uniform overtaking process and the accelerated overtaking process are compared. It is shown that the speed variation of the overtaking van would influence the aerodynamic characteristics of the two vans, with greater influence on the overtaken van than on the overtaking van. The simulations of three different accelerated overtaking processes show that the greater the acceleration of the overtaking van, the larger the aerodynamic coefficients of the overtaken van. When the acceleration of the overtaking van increases by 1 m/s2, the maximum drag force, side force and yawing moment coefficients of the overtaken van all increase by more than 6%, to seriously affect the power performance and the stability of the vehicles. The analysis of the pressure fields under different accelerated conditions reveals the cause of variations of the aerodynamic characteristics of vehicles.

Socialization Practices, Job Satisfaction and Commitment,

DTIC Science & Technology

1983-01-01

organizational entry practice? Neither researchers nor practitioners have directly addressed this issue. Van Manen ( Van Hasnen, 1978) identified seven dimensions...TR-2 John Van Maanen, "Some Thoughts (and Afterthoughts) on Context, Interpretation, and Organization Theory" February, 1982. TR1-3 John Van Maanen...Contradictions in Technical Careers" March, 1982; Working Paper 1281-82. TR-5 John Van Maanen & Deborah Kolb. "The Professional Apprentice: Observations on Fie1

Inventarisatie telematica-ontwikkelingen Natco (Inventory Telematics Developments Natco)

DTIC Science & Technology

1998-05-01

telefonie, die binnen afzienbare tijd een bereikbaarheid over nagenoeg de gehele wereldbol kan garanderen. Ook hier is de koppeling van netwerken van...PCS is ’de mogelijkheid voor een gebruiker te communiceren in elke gewenste vorm, op elke tijd , op elke plaats en in verschillende rollen...wat betreft plaats, tijd en tempo van het leren, kan worden gerealiseerd. De toepassing van teleleren kan leiden tot een verbetering van de interne

Evaporation from Sand

DTIC Science & Technology

1992-04-01

Instituuts Advies R2ad PML Prof. dr. U.A.Th. Brinkanl~ 36. Direactur van het Medisch Biologisch Laboratorium TNO Prof.Dr. W.R.F. Notten 37. Directeur...Grootsdialige Rampenbestrijdcing Ministerie van Binnenlandsc Zaken Drs. H. Evers 9. Adviseur van het Prins Maurits Laboratorium TWO Prot. Dr. J.M. van...Rossum, 10. Adyisew, van het Prins Maurits Laboratorium TWO Chernisdie Research Prof.Dr. G. Dijkstra 11. H~ur. NBC DMKIJOMAT/KIO Ir. AAM. Slagveer 12

Mobile Telemetry Van Remote Control Upgrade

DTIC Science & Technology

2012-05-17

Advantages of Remote Control System Upgrade • Summary Overview • Remote control of Telemetry Mobile Ground Support ( TMGS ) Van proposed to allow...NWC) personnel provided valuable data for full-function remote control of telemetry tracking vans Background • TMGS Vans support Flight Test...control capability from main TM site at Building 5790 currently allows support via TMGS Van at nearby C- 15 Site, Plant 42 in Palmdale, and as far

Spiroplasma infection causes either early or late male killing in Drosophila, depending on maternal host age

NASA Astrophysics Data System (ADS)

Kageyama, Daisuke; Anbutsu, Hisashi; Shimada, Masakazu; Fukatsu, Takema

2007-04-01

Symbiont-induced male-killing phenotypes have been found in a variety of insects. Conventionally, these phenotypes have been divided into two categories according to the timing of action: early male killing at embryonic stages and late male killing at late larval stages. In Drosophila species, endosymbiotic bacteria of the genus Spiroplasma have been known to cause early male killing. Here, we report that a spiroplasma strain normally causing early male killing also induces late male killing depending on the maternal host age: male-specific mortality of larvae and pupae was more frequently observed in the offspring of young females. As the lowest spiroplasma density and occasional male production were also associated with newly emerged females, we proposed the density-dependent hypothesis for the expression of early and late male-killing phenotypes. Our finding suggested that (1) early and late male-killing phenotypes can be caused by the same symbiont and probably by the same mechanism; (2) late male killing may occur as an attenuated expression of early male killing; (3) expression of early and late male-killing phenotypes may be dependent on the symbiont density, and thus, could potentially be affected by the host immunity and regulation; and (4) early male killing and late male killing could be alternative strategies adopted by microbial reproductive manipulators.

Geodetic investigation of plate spreading along a propagating ridge: the Eastern Volcanic Zone, Iceland

NASA Astrophysics Data System (ADS)

Scheiber-Enslin, Stephanie E.; Lafemina, Peter C.; Sturkell, Erik; Hooper, Andrew J.; Webb, Susan J.

2011-12-01

Hotspot-ridge interactions lead to the dynamic evolution of divergent plate boundaries, including propagating and overlapping ridge segments. In southern Iceland, the Eastern Volcanic Zone (EVZ) formed approximately 2-3 Ma ago during the last eastward ridge jump from the Western Volcanic Zone (WVZ), and is propagating to the southwest into the Tertiary lithosphere of the Eastern Volcanic Flank Zone. North America-Eurasia relative plate motion is partitioned between the Eastern and WVZs. We utilize new terrestrial (dry-tilt) and space (GPS and InSAR) geodetic data to investigate the nature of plate spreading and magma-tectonic interaction at the southern terminus of this propagating ridge system. We present a new GPS derived horizontal velocity field covering the period 1994-2006, new InSAR analyses for the periods 1993-2000 and 2003-2007, and models of plate spreading across this region. The velocity field indicates horizontal surface deformation consistent with plate spreading across and the propagation of the EVZ. The dry-tilt and InSAR data show transient deformation signals associated with magmatic processes. The velocity field is corrected for these transient deformation sources in order to investigate the nature of secular plate motion. Our model results indicate a decrease in spreading rate from northeast (15 mm yr-1) to southwest (9 mm yr-1) across the Torfajökull caldera and the intersection of the South Iceland Seismic Zone and EVZ, consistent with the propagating ridge model. Plate spreading south of the intersection demonstrates that spreading must be partitioned with the Reykjanes Peninsula to the west at this latitude. Our results also constrain the minimum flux (0.05 km3 km-1 kyr-1) of magma to this segment of the Mid-Atlantic Ridge and indicate that the Hekla magmatic system strains the Torfajökull caldera during pre- and co-eruptive periods.

Long-period seismic events with strikingly regular temporal patterns on Katla volcano's south flank (Iceland)

NASA Astrophysics Data System (ADS)

Sgattoni, Giulia; Jeddi, Zeinab; Gudmundsson, Ólafur; Einarsson, Páll; Tryggvason, Ari; Lund, Björn; Lucchi, Federico

2016-09-01

Katla is a threatening volcano in Iceland, partly covered by the Mýrdalsjökull ice cap. The volcano has a large caldera with several active geothermal areas. A peculiar cluster of long-period seismic events started on Katla's south flank in July 2011, during an unrest episode in the caldera that culminated in a glacier outburst. The seismic events were tightly clustered at shallow depth in the Gvendarfell area, 4 km south of the caldera, under a small glacier stream at the southern margin of Mýrdalsjökull. No seismic events were known to have occurred in this area before. The most striking feature of this seismic cluster is its temporal pattern, characterized by regular intervals between repeating seismic events, modulated by a seasonal variation. Remarkable is also the stability of both the time and waveform features over a long time period, around 3.5 years. We have not found any comparable examples in the literature. Both volcanic and glacial processes can produce similar waveforms and therefore have to be considered as potential seismic sources. Discerning between these two causes is critical for monitoring glacier-clad volcanoes and has been controversial at Katla. For this new seismic cluster on the south flank, we regard volcano-related processes as more likely than glacial ones for the following reasons: 1) the seismic activity started during an unrest episode involving sudden melting of the glacier and a jökulhlaup; 2) the glacier stream is small and stagnant; 3) the seismicity remains regular and stable for years; 4) there is no apparent correlation with short-term weather changes, such as rainstorms. We suggest that a small, shallow hydrothermal system was activated on Katla's south flank in 2011, either by a minor magmatic injection or by changes of permeability in a local crack system.

Evaluation of the Physical and Chemical Properties of Eyjafjallajökull Volcanic Plume Using a Cloud-Resolving Model

NASA Astrophysics Data System (ADS)

Spiridonov, Vlado; Curic, Mladjen

2013-11-01

The Eyjafjallajökull volcanic eruption, which occurred on April 14, 2010, caused many environmental, air traffic and health problems. An attempt has been made to demonstrate for the first time that certain improvements could be made in the quantitative prediction of the volcanic ash parameters, and in the accounting of the processes in the immediate vicinity of the volcano, using a cloud-resolving model. This type of explicit modeling by treatment of volcanic ash and sulfate chemistry parameterization, with input of a number parameters describing the volcanic source, is the way forward for understanding the complex processes in plumes and in the future plume dispersion modeling. Results imply that the most significant microphysical processes are those related to accretion of cloud water, cloud ice and rainwater by snow, and accretion of rain and snow by hail. The dominant chemical conversion rates that give a great contribution to the sulfate budget are nucleation and dynamic scavenging and oxidation processes. A three-dimensional numerical experiment has shown a very realistic simulation of volcanic ash and other chemical compounds evolution, with a sloping structure strongly influenced by the meteorological conditions. In-cloud oxidation by H2O2 is the dominant pathway for SO2 oxidation and allows sulfate to be produced within the SO2 source region. The averaged cloud water pH of about 5.8 and rainwater pH of 4.5 over simulation time show quantitatively how the oxidation may strongly influence the sulfate budget and acidity of volcanic cloud. Compared to observations, model results are close in many aspects. Information on the near field volcanic plume behavior is essential for early preparedness and evacuation. This approach demonstrates a potential improvement in quantitative predictions regarding the volcanic plume distribution at different altitudes. It could be a useful tool for modeling volcanic plumes for better emergency measures planning.

Near-field monitoring of the Eyjafjallajökull eruption cloud

NASA Astrophysics Data System (ADS)

Bjornsson, H.; Pedersen, G. N.; Arason, P.; Karlsdottir, S.; Vogfjord, K. S.; Thorsteinsson, H.; Palmason, B.; Sigurdsson, A.

2010-12-01

When the ice capped Eyjafjallajökull volcano erupted in April 2010 the Icelandic Meteorological Office (IMO) employed range of observation systems to monitor the eruption cloud and the progress of the eruption. The main tool for monitoring the volcanic cloud was a C-band weather radar located at Keflavik international airport, about 150 km from the volcano. Radar monitoring was supported by visual observations, on-site and from a network of web-cameras. Airborne observations allowed for detailed examination of the plume, and pilot reports proved to be an extremely useful aid in verifying the radar data. Furthermore, data from lightning sensors and radiosondes was used to supplement information on plume height. Satellite images, from several frequency bands and both polar as well as geostationary satellites were used to track the orientation of the eruption cloud, and brightness temperature difference was used to estimate far field ash dispersal. Ash fall monitoring and meteorological observations supplemented with atmospheric reanalysis and wind forecasts were used to track local ash dispersal. Information from these data sources was combined with geophysical and hydrological measurements (seismic, GPS, strain and river flow gauges) made by the IMO, the Earth Institute of the University of Iceland and other institutions. The data generated by these different observation types gives a consistent picture of the progression of the eruption and reveals interesting connections. For example, volcanic tremors tended to be inversly related to the eruption cloud height, increasing tremors were associated lower plume height and reduced eruption strength. Furthermore, the occurrence of lighting seems to be explained by both sufficiently strong plume and cold ambient air. Wind also had a clear effect on the eruption cloud height. In general, simple scaling laws for the relationship between the emission rate of the volcano, and the height of the eruption do not seem to explain all the height variations in the eruption cloud.

Geomorphic change detection in proglacial areas using repetitive unmanned aerial vehicle (UAV) surveys

NASA Astrophysics Data System (ADS)

Ewertowski, Marek; Evans, David; Roberts, David; Tomczyk, Aleksandra; Ewertowski, Wojciech

2017-04-01

Glacial forelands exposed due to the glacier recession are one of the most dynamically transformed landscapes in Polar and mountainous areas. These areas are supposed to be intensively changed by various geomorphological processes related to the glacial retreat and meltwater activity, as well as paraglacial adjustment of topography. This study deals with landscape transformation in an annual time-scale in the foreland of Hørbyebreen and Rieperbreen (Svalbard) and Fjallsjökull and Kviárjökull (Iceland) to assess landscape changes in 2014-2016 period. The main aim of this study is to map and quantify landforms development in detailed spatial scale to provide an insight into geomorphological processes which occurred shortly after the retreat of the ice margin. Low-altitude aerial photographs were taken using small quadcopter equipped with 12 MP camera. Images were acquired at an elevation between 40 and 60 m above the ground level. The images were subsequently processed using structure-from-motion approach to produce orthomosaics ( 3 cm cell size) and digital elevation models (DEMs) with 5-10 cm cell size. Subtracting DEMs from subsequent time periods created DEMs of Differences — which enabled us to calculate the amount of material loss or deposition. Accuracy of the orthophotos and DEMs was improved using ground control points measured with dGPS. Over the 2014-2016 period repetitive UAV-based surveys revealed and quantify changes in landscape including: (1) glacier thinning; (2) ice-cored moraines degradation; (3) development of terminoglacial and supraglacial lakes; (4) debris flow activity. Short-time dynamics of different components showed very high variability over time and space illustrating relative importance of ice backwasting and downwasting as well as glacifluvial processes for studied forelands The research was founded by Polish National Science Centre (project granted by decision number DEC-2011/01/D/ST10/06494).

Glacier discharge and climate variations

NASA Astrophysics Data System (ADS)

Dominguez, M. Carmen; Rodriguez-Puebla, Concepcion; Encinas, Ascension H.; Visus, Isabel; Eraso, Adolfo

2010-05-01

Different studies account for the warming in the polar regions that consequently would affect Glacier Discharge (GD). Since changes in GD may cause large changes in sensible and latent heat fluxes, we ask about the relationships between GD and climate anomalies, which have not been quantified yet. In this study we apply different statistical methods such as correlation, Singular Spectral Analysis and Wavelet to compare the behaviour of GD data in two Experimental Pilot Catchments (CPE), one (CPE-KG-62°S) in the Antarctica and the other (CPE-KVIA-64°N) in the Arctic regions. Both CPE's are measuring sub- and endo-glacier drainage for recording of glacier melt water run-off. The CPE-KG-62°S is providing hourly GD time series since January 2002 in Collins glacier of the Maxwell Bay in King George Island (62°S, 58°W). The second one, CPE-KVIA-64°N, is providing hourly GD time series since September 2003 in the Kviarjökull glacier of the Vatnajökull ice cap in Iceland (64°N, 16°W). The soundings for these measurements are pressure sensors installed in the river of the selected catchments for the ice cap (CPE-KG-62°S) and in the river of the glacier for (CPE-KVIA-64°N). In each CPE, the calibration function between level and discharge has been adjusted, getting a very high correlation coefficient (0.99 for the first one and 0.95 for the second one), which let us devise a precise discharge law for the glacier. We obtained relationships between GD with atmospheric variables such as radiation, temperature, relative humidity, atmospheric pressure and precipitation. We also found a negative response of GD to El Niño teleconnection index. The results are of great interest due to the GD impact on the climate system and in particular for sea level rise.

Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards: Part I. Validation of satellite-derived Volcanic Ash Levels.

NASA Astrophysics Data System (ADS)

Koukouli, MariLiza; Balis, Dimitris; Simopoulos, Spiros; Siomos, Nikos; Clarisse, Lieven; Carboni, Elisa; Wang, Ping; Siddans, Richard; Marenco, Franco; Mona, Lucia; Pappalardo, Gelsomina; Spinetti, Claudia; Theys, Nicolas; Tampellini, Lucia; Zehner, Claus

2014-05-01

The 2010 eruption of the Icelandic volcano Eyjafjallajökull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. Major disruptions in European air traffic were observed for several weeks surrounding the two eruptive episodes, which had a strong impact on the everyday life of many Europeans as well as a noticable economic loss of around 2-3 billion Euros in total. The eruptions made obvious that the decision-making bodies were not informed properly and timely about the commercial aircraft capabilities to ash-leaden air, and that the ash monitoring and prediction potential is rather limited. After the Eyjafjallajökull eruptions new guidelines for aviation, changing from zero tolerance to newly established ash threshold values, were introduced. Within this spirit, the European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction . This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation using auxiliary satellite, aircraft and ground-based measurements. The validation of volcanic ash levels extracted from the sensors GOME-2/MetopA, IASI/MetopA and MODIS/Terra and MODIS/Aqua is presented in this work with emphasis on the ash plume height and ash optical depth levels. Co-located aircraft flights, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation [CALIPSO] soundings and well as European Aerosol Research Lidar Network [EARLINET] measurements were compared to the different satellite estimates for the those two eruptive episodes. The validation results are extremely promising with most satellite sensors performing quite well and within the estimated uncertainties compared to the comparative datasets. The findings are extensively presented here and future directions discussed in length.

Synthetic Minor NSR Permit: Van Hook Crude Terminal, LLC - Van Hook Crude Terminal/Rail Loading Facility

EPA Pesticide Factsheets

This page contains the current effective synthetic minor NSR permit for the Van Hook Crude Terminal, LLC, Van Hook Crude Terminal/Rail Loading Facility, located on the Fort Berthold Indian Reservation in Mountrail County, ND.

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

Hidden symmetries and Lie algebra structures from geometric and supergravity Killing spinors

NASA Astrophysics Data System (ADS)

Açık, Özgür; Ertem, Ümit

2016-08-01

We consider geometric and supergravity Killing spinors and the spinor bilinears constructed out of them. The spinor bilinears of geometric Killing spinors correspond to the antisymmetric generalizations of Killing vector fields which are called Killing-Yano forms. They constitute a Lie superalgebra structure in constant curvature spacetimes. We show that the Dirac currents of geometric Killing spinors satisfy a Lie algebra structure up to a condition on 2-form spinor bilinears. We propose that the spinor bilinears of supergravity Killing spinors give way to different generalizations of Killing vector fields to higher degree forms. It is also shown that those supergravity Killing forms constitute a Lie algebra structure in six- and ten-dimensional cases. For five- and eleven-dimensional cases, the Lie algebra structure depends on an extra condition on supergravity Killing forms.

Presence of the resistance genes vanC1 and pbp5 in phenotypically vancomycin and ampicillin susceptible Enterococcus faecalis.

PubMed

Schwaiger, Karin; Bauer, Johann; Hörmansdorfer, Stefan; Mölle, Gabriele; Preikschat, Petra; Kämpf, Peter; Bauer-Unkauf, Ilse; Bischoff, Meike; Hölzel, Christina

2012-08-01

Ampicillin and vancomycin are important antibiotics for the therapy of Enterococcus faecalis infections. The ampicillin resistance gene pbp5 is intrinsic in Enterococcus faecium. The vanC1 gene confers resistance to vancomycin and serves as a species marker for Enterococcus gallinarum. Both genes are chromosomally located. Resistance to ampicillin and vancomycin was determined in 484 E. faecalis of human and porcine origin by microdilution. Since E. faecalis are highly skilled to acquire resistance genes, all strains were investigated for the presence of pbp5 (and, in positive strains, for the penicillin-binding protein synthesis repressor gene psr) and vanC1 (and, in positive strains, for vanXYc and vanT) by using polymerase chain reaction (PCR). One porcine and one human isolate were phenotypically resistant to ampicillin; no strain was vancomycin resistant. Four E. faecalis (3/1 of porcine/human origin) carried pbp5 (MIC=1 mg/L), and four porcine strains were vanC1 positive (minimum inhibitory concentration [MIC]=1 mg/L). Real-time reverse transcriptase (RT)-PCR revealed that the genes were not expressed. The psr gene was absent in the four pbp5-positive strains; the vanXYc gene was absent in the four vanC1-positive strains. However, vanT of the vanC gene cluster was detected in two vanC1-positive strains. To our knowledge, this is the first report on the presence of pbp5, identical with the "E. faecium pbp5 gene," and of vanC1/vanT in E. faecalis. Even if resistance is not expressed in these strains, this study shows that E. faecalis have a strong ability to acquire resistance genes-and potentially to spread them to other bacteria. Therefore, close monitoring of this species should be continued.

Thermal Stability of Volcanic Ash versus Turbine Ingestion Test Sands: an Experimental Investigation

NASA Astrophysics Data System (ADS)

Cimarelli, C.; Kueppers, U.; Hess, K.; Dingwell, D. B.; Rickerby, D. S.; Madden, P. C.

2010-12-01

Volcanic eruptions are an inevitable natural threat. The range of eruptive styles is large and short term fluctuations of explosivity or vent position pose a large risk not necessarily confined to the immediate vicinity of a volcano. Explosive eruptions rather may also affect aviation, infrastructure and climate, regionally as well as globally. The recent eruption of Eyjafjallajökull drastically brought into common awareness how volcanic activity can affect every day’s life and disrupt air traffic. The presence of solid particles in the air ingested in jet turbines may cause harm as it 1) may deposit on surfaces upon being heated up and 2) abrade upon impact. Particles suspended in the atmosphere may have different origins, including volcanic ash, aeolian sand, or incineration residues, each of them having different chemical and physical characteristics. To date, aircraft turbine operability has been investigated - amongst other tests - through the ingestion of sands whose grains have different mineralogical nature. Due to high cooling rates, volcanic ash is usually made up of glass, i.e. an amorphous phase lacking crystallographic order. Glass and crystal behave very differently to heating up. Glass will soften - and accordingly change shape or stick to surfaces - at temperatures as low as 700 °C, depending on the chemical composition. Crystals however need higher melting temperatures; quartz for example has a melting point at around 1700 °C. Accordingly, the effect of ash on the operational reliability of aircraft turbines may not be judged solely based on knowledge commonly derived from mineral sand ingestion testing. In order to investigate the behaviour upon heating, we performed a series of experiments at ten temperature steps between 700 and 1600 °C. We used three different samples: 1) Ash from the explosive phase of Eyjafjallajökull; 2) MIL E-5007C test sand (MTS), and 3) Arizona Test Dust (ATD). MTS and ATD are commonly used for aircraft turbine testing. Experiments have been performed on two different grain sizes, < 63 and 90

77 FR 14583 - Notice to Manufacturers of Alternative Fuel Vans

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-12

... Alternative Fuel Vans AGENCY: Federal Aviation Administration (FAA), U.S. DOT. ACTION: Notice to Manufacturers of Alternative Fuel Vans. SUMMARY: Projects funded under the Airport Improvement Program (AIP) must... (FAA) is considering issuing waivers to foreign manufacturers of alternative fuel vans. This notice...

Dynamical importance of van der Waals saddle and excited potential surface in C(1D)+D2 complex-forming reaction

PubMed Central

Shen, Zhitao; Ma, Haitao; Zhang, Chunfang; Fu, Mingkai; Wu, Yanan; Bian, Wensheng; Cao, Jianwei

2017-01-01

Encouraged by recent advances in revealing significant effects of van der Waals wells on reaction dynamics, many people assume that van der Waals wells are inevitable in chemical reactions. Here we find that the weak long-range forces cause van der Waals saddles in the prototypical C(1D)+D2 complex-forming reaction that have very different dynamical effects from van der Waals wells at low collision energies. Accurate quantum dynamics calculations on our highly accurate ab initio potential energy surfaces with van der Waals saddles yield cross-sections in close agreement with crossed-beam experiments, whereas the same calculations on an earlier surface with van der Waals wells produce much smaller cross-sections at low energies. Further trajectory calculations reveal that the van der Waals saddle leads to a torsion then sideways insertion reaction mechanism, whereas the well suppresses reactivity. Quantum diffraction oscillations and sharp resonances are also predicted based on our ground- and excited-state potential energy surfaces. PMID:28094253

International Hydrogenase Conference (7th) Held at the University of Reading on August 24th to 29th 2004.

DTIC Science & Technology

2004-08-19

Johannes Hackstein [ PB GIO rNovel Fe-hydrogenases from the rumen ciliate metagenome . :12.50 :114.00 -1 Lunch [ 114.00 1 7.00 1 Poster Session 2...d.r.o’ g’.e n-.a-.s.e..s from the rumnen ciliate metagenome . p36 Severing, E., Boxma, B., van Alen, T.A., Ricard, G., van Hoek, A.H.A.M., Moon-van...hydrogenases from the rumen ciliate metagenome . Severing, E.’, Boxma, B.1, van Alen, T.A.’, Ricard, G.z, van Hoek, A.H.A.M.’, Moon-van der Staay, S.Y

Genetics Home Reference: bare lymphocyte syndrome type II

MedlinePlus

... 6. Citation on PubMed Gobin SJ, Peijnenburg A, van Eggermond M, van Zutphen M, van den Berg R, van den Elsen PJ. The RFX complex is crucial ... D, Szöllosi J, Jenei A. Bare lymphocyte syndrome: an opportunity to discover our immune system. Immunol Lett. ...

Measurements of Propeller-Induced Unsteady Surface Force and Pressures

DTIC Science & Technology

1986-12-01

investigations using foreshortened hull models in the determination of cavitating propeller-induced pressure pulses include van Manen , 46 Huse,47 van Oossanen...Nov 1974). 46. van Manen , J.D., "The Effect of Cavitation on the Interaction Between Propeller and Ship’s Hull, "International Shipbuilding Progress...and van der Kooij,48 and van der Kooij and Jonk. 49 Examples of more recent publications that have either made use of results from dummy model tests or

Job Oriented Training: Onderwijskundige Grondslag en Onderbouwing (Job Oriented Training: Foundation and Empirical Support)

DTIC Science & Technology

2008-07-01

die binmen defensie tot aanzien van de effecten van JOT onderwijs met het nieuwe leren terug te dan toe in gebruik waren bij het theorie - voeren is op...problemen in de uitvoerings- onderwijs; toepassing van JOT impliceerde Grondslag praktijk van datzeltde regulier onderwijs. dat er geen theorie meer...het rechte eind Opdrachtnummer Datum PROGRAMMA PROJECT juli 2008 Program mabegeleider Projectbegeleider Auteur (s) IkolP.M.. Bonen,dr. A.H. van der

Combination Vancomycin/Cefazolin (VAN/CFZ) for Methicillin-Resistant Staphylococcus aureus (MRSA) Bloodstream Infections (BSI)

PubMed Central

Trinh, Trang D; Zasowski, Evan J; Lagnf, Abdalhamid M; Bhatia, Sahil; Dhar, Sorabh; Mynatt, Ryan; Pogue, Jason M; Rybak, Michael J

2017-01-01

Abstract Background VAN remains the standard for MRSA BSI but has been associated with treatment failures and resulted in prolonged BSI durations and recurrences. In vitro studies of VAN/CFZ against MRSA demonstrated synergy and prevention of VAN resistance. However, clinical use of VAN/CFZ has not been reported. The objective of this study was to compare patient outcomes treated with VAN/CFZ vs. VAN for MRSA BSI. Methods This was a retrospective, cohort, comparative-effectiveness study of hospitalized adults ≥18y with ≥1 MRSA blood culture and received VAN/CFZ combination for ≥24h or VAN alone initiated within 72h of index infection between 1/1/08 and 5/1/17. Patients who received >24h β-lactams other than CFZ, MRSA-active antibiotics other than VAN, with polymicrobial BSI, or had a second MRSA BSI episode during the study period were excluded. The primary composite failure outcome included: 30d mortality, MRSA BSI ≥7d, and 60d recurrence. Demographics were compared by Χ2, Fisher’s exact, Student’s t, or Mann–Whitney U tests. Multivariable regression models compared outcomes between the two treatment groups. Covariates with p-values ≤0.2 in bivariate analyses were included in the model. Results A total of 101 patients were included (CFZ/VAN = 41, VAN = 60). Demographics were similar except VAN patients were older (mean (±SD) age 58 (±14) v. 51 (±18) y, P = 0.04), had higher median (IQR) Charlson Comorbidity Index (3 (2-5) v. 1 (0–4), P < 0.01), APACHE II scores (13 (8-18) v. 11 (8-18), P = 0.2), and more endocarditis BSI source (37% v. 20%, P = 0.06). After accounting for BSI source, VAN/CFZ (adjusted odds ratio [aOR], 95% confidence intervals [CI], 0.33, 0.13-0.83) and low APACHE II scores (aOR 1.07, 95% CI 1–1.15) were independently associated with fewer failures. Bivariate outcomes are in table below: Variable, n (%) VAN/CFZ VAN P value Composite failure 10 (24) 31 (52) 0.006 30d mortality 3 (7.3) 5 (8.3) 1 BSI ≥7d 6 (15) 21 (35) 0.023 60d recurrence 3 (7.3) 9 (15) 0.351 Failure switch 1 (2.4) 10 (17) 0.026 Conclusion In this cohort of MRSA BSI, patients treated with VAN/CFZ experienced fewer failures than with VAN alone, with shorter BSI durations. Additional studies are needed to confirm the role of VAN/CFZ combination treatment for MRSA BSI. Disclosures J. M. Pogue, Achaogen, Inc.: Consultant, Consulting fee. M. J. Rybak, Allergen: Scientific Advisor, Consulting fee.

Learning from Profiles of the Special Needs Gifted

ERIC Educational Resources Information Center

Swanson, Julie Dingle; Van Tassel-Baska, Joyce; Feng, Annie; Chandler, Kimberley

2007-01-01

Through a longitudinal study focused on identification policy that is inclusive of underrepresented gifted students (Van Tassel-Baska & Feng, 2003; Van Tassel-Baska, Feng, & deBrux, under review; Van Tassel-Baska, Feng, & Evans, in press; Van Tassel-Baska, Johnson, & Avery, 2002), a team of researchers developed case studies of special needs…

78 FR 47487 - Notice of Proposed Buy America Waiver

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-05

... (NFRMPO). NFRMPO is in the process of procuring vehicles for its vanpool program, ``VanGo.'' In accordance... Organization (NFRMPO). NFRMPO operates a vanpool (``VanGo'') program, which has 75 vans with routes connecting, among others, Fort Collins, Loveland, Greeley, Denver, and Boulder, Colorado. The VanGo program carries...

Representation of Research Paradigms as a Function of Familiarity with Research Domains

DTIC Science & Technology

1992-07-01

van de paradigma’s te kunnen vaststellen. Keuze van het Juiste paradigma werd bepaald door proefpersonen te vragen de betreffende zin te classificeren...als afkomstig van een bepaaid type onderzoek. De innoud van het paradigma werd bepaald door proefpersonen te, vragen zoveel kenmerken voor bet

Additional Value from Road Mapping in Defense Policy Making (meerwaarde van roadmapping bij beleidsontwikkeling van de koninklijke landmacht)

DTIC Science & Technology

2006-05-01

van zogonaamde strategische reserves tot bijvaarbeeld lakaal boschikbare gevechtscapacitoit. 9 11 Joint. Do Nederlandse krijgsmacht ontwikkelt zich tot...8 2 W erkwijze van de KL tot nu toe ............................................................................... 9 2.1 O...ntwikkeling visiedocurnent ....................................................................................... 9 2.2 Opzet beleid- en deelstudies

Structuring of the Renewed Decision Making Process in the Royal Netherlands Army (Structurering van het vernieuwde besluitvormingsproces binnen de KL).

DTIC Science & Technology

1996-10-10

time informatie wordt door Eisenhardt (1989) gedefinieerd als " information about a firm’s operations or environment for which there is little or no...op het invoeren van (getypte) tekst . Conclusie Elektronisch Brainstormen: * in principe geschikt om Eigen Mogelijkheden te genereren, vooral als de...Capaieairt ca •acitenit ca a• C ie•lit Fig. 1 Mogelijke wijzen van besluitvorming (zie tekst ) als functie van beschik- bare tijd, capaciteit en ervaring van

The Design of a Propeller for a U.S. Coast Guard Icebreaker Tugboat

DTIC Science & Technology

1975-10-01

series as investigated by Van Lammeren, Van Manen , and Oosterveld . This propeller series, commonly referred to as the K’jgeningen B-screw series...RtFEKENCES Van Lammeren, W.P.A., Van Manen , J.D., and Oosterveld, M.W.C., "The Wageningen B-Screw Series," Transactions of the Society of Naval Architects...forces has been reported by Van Gunsteren and Pronk . They investigated both single and twin screw ships of various types and the results are

The Role of b-Catenin in Mammary Gland Carcinogenesis

DTIC Science & Technology

2002-03-01

Wetering, M., Cavallo, R., Dooijes, D., van Beest , M., van Es, J., Loureiro, J., Ypma, A., hursh, D., Jones, T., Bejsovec, A., Peifer, M., Mortin, M...Transduction Lab - domain of /3-catenin. oratories) and anti-KT3 (Babco) were used as primary Elevated levels of fl-catenin were recently observed in antibodies...1988). Cell, 55, 619 -625. Kolligs FT, Hu G, Dang CV and Fearon ER. (1999). Mol. van de Wetering M, Cavallo R, Dooijes D, van Beest M, van Cell. Biol

MATE (Mentale Aspecten van Team Effectiviteit) (MATE (Mental Aspects of Team Effectiveness))

DTIC Science & Technology

2008-05-01

0 Auteur (s) drs. J.P. van Meer drs. MI. 1 ’ IIart0 drs. 1. van der 16. Rubricering rapport Ongerubriceerd Vastgesteld door Ikol drs. L.A. de Vos...team Auteur (s) Teamntraining drs. J.P. van Meer drs. M.H.E. I Hart Programmanummer Projectnummer drs. 1. van der Beijl V406 015.34095 Rubricering...Murphy & Cleveland (1995) geven inzicht in de tearngedragingen die meetbaar zijn en de theorie over Shared Mental Models (Espevik et al, 2006) laat zien

De Ontwikkeling van een PBPK Model voor VX; Stand van Zaken V013-813 en 207C (The Development of a PBPK Model for VX: Status Report)

DTIC Science & Technology

2006-02-01

ing. H.C. Trap, dr. ir. M.J. van der werd zes maal gesproken over de Schans, ing. L.F. Chau, B.). Lander, invulling en de voortgang van het I.A. Cordia ...dr. ir. M.J. van der Schans, ing. L.F. Chau, J.P. Oostdijk, B.J. Lander, l.A. Cordia 25 TNO Defensie en Veiligheid, vestiging Rijswijk, Marketing en

Speed Measuring System (Detectoren en Signaalbewerking Voor Het Snelheidsmeetsysteem 4-01)

DTIC Science & Technology

1989-03-01

een hogere nauwkeurigheid te halen dan san de voet van bet signasi mogelijk is bij een grote signaalaniplitude, Wanneer de S/L < 6 is wordt de drempel...snelheidsmeetsysteem 4-01 Niets Uilf deze ultgave mag worden vermenigvuldigd en of openbaar gemaakt door mlddel van druk fotokope microfilm autour~s): of op welke...andere wijze dan 006 zonder voorafgaarode toestemming van TNO J. van der Haven Hetlter I zage geven van net TNO-rappoit aan direct belanghebbenoen is

Eisen voor Buitenbeelden van Voertuigsimulatoren: Een Literatuurstudie (Use of Exterior Pictures in Vehicle Simulators: A Literature Survey)

DTIC Science & Technology

1991-06-01

1.3 Opleiding en onderzoek met voertuigsimulatoren 9 1.4 Opbouw van simulatoren 11 1.5 Totstandkomning van beelden in CGI-systemen 13 1.6 Bepalen van...pictures in vehicle simulators. A literature survey s 029 9 20 Aantal bladzijden: 102 .JISTRIBIYI±WN- STATEMEN9 -2 39 Approved for public release; 2 28 9 ...Achteruitkijkspiegels en verrekijkers 79 8.2 Helderheidsversterkers en warmtebeelden 80 8.3 Middelen om afstand te bepalen 80 9 INTERACTIES VAN HET

Imaging burst kinetics and spatial coordination during serial killing by single natural killer cells

PubMed Central

Choi, Paul J.; Mitchison, Timothy J.

2013-01-01

Cytotoxic lymphocytes eliminate virus-infected and cancerous cells by immune recognition and killing through the perforin-granzyme pathway. Traditional killing assays measure average target cell lysis at fixed times and high effector:target ratios. Such assays obscure kinetic details that might reveal novel physiology. We engineered target cells to report on granzyme activity, used very low effector:target ratios to observe potential serial killing, and performed low magnification time-lapse imaging to reveal time-dependent statistics of natural killer (NK) killing at the single-cell level. Most kills occurred during serial killing, and a single NK cell killed up to 10 targets over a 6-h assay. The first kill was slower than subsequent kills, especially on poor targets, or when NK signaling pathways were partially inhibited. Spatial analysis showed that sequential kills were usually adjacent. We propose that NK cells integrate signals from the previous and current target, possibly by simultaneous contact. The resulting burst kinetics and spatial coordination may control the activity of NK cells in tissues. PMID:23576740

Fluorescent vancomycin and terephthalate comodified europium-doped layered double hydroxides nanoparticles: synthesis and application for bacteria labelling

NASA Astrophysics Data System (ADS)

Sun, Jianchao; Fan, Hai; Wang, Nan; Ai, Shiyun

2014-09-01

Vancomycin (Van)- and terephthalate (TA)-comodified europium-doped layered double hydroxides (Van-TA-Eu-LDHs) nanoparticles were successfully prepared by a two-step method, in which, TA acted as a sensitizer to enhance the fluorescent property and Van was modified on the surface of LDH to act as an affinity reagent to bacteria. The obtained products were characterized by X-ray diffraction, transmission electron microscope and fluorescent spectroscopy. The results demonstrated that the prepared Van- and TA-comodified europium-doped layered double hydroxides (Van-TA-Eu-LDHs) nanoparticles with diameter of 50 nm in size showed highly efficient fluorescent property. Furthermore, due to the high affinity of Van to bacteria, the prepared Van-TA-Eu-LDHs nanoparticles showed efficient bacteria labelling by fluorescent property. The prepared nanoparticles may have wide applications in the biological fields, such as biomolecular labelling and cell imaging.

It's not just conflict that motivates killing of orangutans.

PubMed

Davis, Jacqueline T; Mengersen, Kerrie; Abram, Nicola K; Ancrenaz, Marc; Wells, Jessie A; Meijaard, Erik

2013-01-01

We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents' active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed.

It’s Not Just Conflict That Motivates Killing of Orangutans

PubMed Central

Davis, Jacqueline T.; Mengersen, Kerrie; Abram, Nicola K.; Ancrenaz, Marc; Wells, Jessie A.; Meijaard, Erik

2013-01-01

We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents’ active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed. PMID:24130707

Defending commercial surrogate motherhood against Van Niekerk and Van Zyl.

PubMed Central

McLachlan, H V

1997-01-01

The arguments of Van Niekerk and Van Zyl that, on the grounds that it involves an inappropriate commodification and alienation of women's labour, commercial surrogate motherhood (CSM) is morally suspect are discussed and considered to be defective. In addition, doubt is cast on the notion that CSM should be illegal. PMID:9451602

Alternative Fuels Data Center: Renzenberger Inc Saves Money With Propane

Science.gov Websites

Vans Renzenberger Inc Saves Money With Propane Vans to someone by E-mail Share Alternative Fuels Data Center: Renzenberger Inc Saves Money With Propane Vans on Facebook Tweet about Alternative Fuels Data Center: Renzenberger Inc Saves Money With Propane Vans on Twitter Bookmark Alternative Fuels

77 FR 44683 - Phillips-Van Heusen Corporation, IZOD Dress Furnishings Division, New York, NY; Notice of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-30

... for Reconsideration for the workers and former workers of Phillips-Van Heusen Corporation, IZOD Women... Phillips-Van Heusen Corporation, IZOD Women's Wholesale Division, New York, New York has not increased. In... Phillips-Van Heusen Corporation, IZOD Women's Wholesale Division, New York, New York) was incorrect, that...

15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

15 CFR 30.26 - Reporting of vessels, aircraft, cargo vans, and other carriers and containers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... vehicles, trailers, pallets, cargo vans, lift vans, or similar shipping containers are not considered... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Reporting of vessels, aircraft, cargo vans, and other carriers and containers. 30.26 Section 30.26 Commerce and Foreign Trade Regulations...

UPS Hybrid Electric Delivery Van Testing | Transportation Research | NREL

Science.gov Websites

conventional diesel vans. Publications The following documents provide detailed information about the study the conventional vans during the on-road portion of the study. The two vehicle groups switched route assignments during the study period to provide a balanced review of the vans on the same routes. During

Probing the binding of phenolic aldehyde vanillin with bovine serum albumin: Evidence from spectroscopic and docking approach.

PubMed

Siddiqui, Gufran Ahmed; Siddiqi, Mohammad Khursheed; Khan, Rizwan Hasan; Naeem, Aabgeena

2018-05-08

The interactions of bovine serum albumin (BSA) with vanillin (VAN) were studied using UV-vis absorption, fluorescence, synchronous fluorescence, three dimensional fluorescence spectroscopy (3D), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and molecular docking techniques. The results revealed that VAN causes the static quenching of BSA by forming BSA-VAN complex. The thermodynamic parameters obtained using isothermal titration calorimetry (ITC) showed that the interaction between BSA and VAN is spontaneous and hydrogen bonding, van der Waals forces are mainly involved in stabilizing the complex. The distance between the donor and the acceptor was analyzed using fluorescence resonance energy transfer (FRET) which showed Forster distance of 2.58 nm. Molecular docking technique was applied to study the modes of interaction between BSA-VAN system and it was found that VAN bound to the sub-domain IIA of BSA. Structural analysis using 3D, synchronous fluorescence FTIR, and CD showed that upon binding of VAN, BSA exhibits small micro-environmental changes around tryptophan amino acid residue. Copyright © 2018. Published by Elsevier B.V.

Relationship of the Van Herick Grading System with Peripheral Iris Configuration and Level of Iris Insertion.

PubMed

Khan, Faisal Aziz; Niazi, Shafaq Pervez Khan; Khan, Assad Zaman

2017-09-01

To determine the relationship of the van Herick angle grading system with the level of iris insertion and peripheral iris configuration. Observational study. Eye department, Combined Military Hospital, Malir Cantt., Karachi, from May to October 2015. Sixty-five eyes of 65 patients were recruited. Anterior chamber depth at the temporal limbus was measured as a fraction of corneal section thickness using van Herick technique and graded on the standard 4-point scale of the van Herick grading system. Gonioscopy of the temporal quadrant was performed with a Posner 4 mirror goniolens and both the true level of iris insertion and peripheral iris configuration were recorded on a 4-point scale so as to equate with the van Herick 4-point grading system. Spearman's rho test was applied to determine the relationship of the van Herick grading system with level of iris root insertion and peripheral iris configuration. Amoderate positive correlation between van Herick grade and peripheral iris configuration was found which was statistically significant (rs=0.42, p < 0.001). Astatistically significant and moderate positive correlation was also detected between van Herick grade and the level of iris insertion (rs=0.45, p < 0.001). The van Herick grade has a moderately positive relationship with the peripheral iris configuration and true level of iris insertion.

Transcriptional Analysis of the vanC Cluster from Enterococcus gallinarum Strains with Constitutive and Inducible Vancomycin Resistance

PubMed Central

Panesso, Diana; Abadía-Patiño, Lorena; Vanegas, Natasha; Reynolds, Peter E.; Courvalin, Patrice; Arias, Cesar A.

2005-01-01

The vanC glycopeptide resistance gene cluster encodes enzymes required for synthesis of peptidoglycan precursors ending in d-Ala-d-Ser. Enterococcus gallinarum BM4174 and SC1 are constitutively and inducibly resistant to vancomycin, respectively. Analysis of peptidoglycan precursors in both strains indicated that UDP-MurNAc-tetrapeptide and UDP-MurNAc-pentapeptide[d-Ser] were synthesized in E. gallinarum SC1 only in the presence of vancomycin (4 μg/ml), whereas the “resistance” precursors accumulated in the cytoplasm of BM4174 cells under both inducing and noninducing conditions. Northern hybridization and reverse transcription-PCR experiments revealed that all the genes from the cluster, vanC-1, vanXYC, vanT, vanRC, and vanSC, were transcribed from a single promoter. In the inducible SC1 isolate, transcriptional regulation appeared to be responsible for inducible expression of resistance. Promoter mapping in E. gallinarum BM4174 revealed that the transcriptional start site was located 30 nucleotides upstream from vanC-1 and that the −10 promoter consensus sequence had high identity with that of the vanA cluster. Comparison of the deduced sequence of the vanSC genes from isolates with constitutive and inducible resistance revealed several amino acid substitutions located in the X box (R200L) and in the region between the F and G2 boxes (D312N, D312A, and G320S) of the putative sensor kinase proteins from isolates with constitutive resistance. PMID:15728903

Heterologous expression of glycopeptide resistance vanHAX gene clusters from soil bacteria in Enterococcus faecalis.

PubMed

Hasman, Henrik; Aarestrup, Frank M; Dalsgaard, Anders; Guardabassi, Luca

2006-04-01

The aim of the study was to determine whether glycopeptide resistance gene clusters from soil bacteria could be heterologously expressed in Enterococcus faecalis and adapt to the new host following exposure to vancomycin. The vanHAX clusters from Paenibacillus thiaminolyticus PT-2B1, Paenibacillus apiarius PA-B2B and Amycolatopsis coloradensis DSM 44225 were separately cloned in an appropriately constructed shuttle vector containing the two-component regulatory system (vanRS) of Tn1546. The complete vanA(PT) operon (vanRSHAXY) from P. thiaminolyticus PT-2B1 was cloned in the same shuttle vector lacking enterococcal vanRS. All plasmid constructs were electroporated into E. faecalis JH2-2 and the MICs of vancomycin and teicoplanin were determined for each recombinant strain before and following exposure to sublethal concentrations of vancomycin. The vanHAX clusters from P. thiaminolyticus and P. apiarius conferred high-level vancomycin resistance (MIC > or = 125 mg/L) in E. faecalis JH2-2. In contrast, cloning of the vanHAX cluster from A. coloradensis did not result in a significant increase of vancomycin resistance (MIC = 0.7 mg/L). Resistance to vancomycin was not observed after cloning the complete vanA(PT) operon from P. thiaminolyticus (MIC = 2 mg/L), but this recombinant rapidly adapted to high concentrations of vancomycin (MIC = 500 mg/L) following exposure to sub-lethal concentrations of this antibiotic. The results showed that vanA(PT) in P. thiaminolyticus is a possible ancestor of vanA-mediated glycopeptide resistance in enterococci. Experimental evidence supported the hypothesis that enterococci did not acquire glycopeptide resistance directly from glycopeptide-producing organisms such as A. coloradensis.

From Attitudes to Actions: Predictors of Lion Killing by Maasai Warriors.

PubMed

Hazzah, Leela; Bath, Alistair; Dolrenry, Stephanie; Dickman, Amy; Frank, Laurence

2017-01-01

Despite legal protection, deliberate killing by local people is one of the major threats to the conservation of lions and other large carnivores in Africa. Addressing this problem poses particular challenges, mainly because it is difficult to uncover illicit behavior. This article examined two groups of Maasai warriors: individuals who have killed African lions (Panthera leo) and those who have not. We conducted interviews to explore the relationship between attitudes, intentions and known lion killing behavior. Factor analysis and logistic regression revealed that lion killing was mainly determined by: (a) general attitudes toward lions, (b) engagement in traditional customs, (c) lion killing intentions to defend property, and (d) socio-cultural killing intentions. Our results indicated that general attitudes toward lions were the strongest predictor of lion killing behavior. Influencing attitudes to encourage pro-conservation behavior may help reduce killing.

New taxa, including three new genera show uniqueness of Neotropical Nepticulidae (Lepidoptera)

PubMed Central

van Nieukerken, Erik J.; Doorenweerd, Camiel; Nishida, Kenji; Snyers, Chris

2016-01-01

Abstract After finding distinct clades in a molecular phylogeny for Nepticulidae that could not be placed in any known genera and discovering clear apomorphic characters that define these clades, as well as a number of Neotropical species that could be placed in known genera but were undescribed, three new genera and nine new species are here described from the Neotropics: Stigmella gallicola van Nieukerken & Nishida, sp. n. reared from galls on Hampea appendiculata (Malvaceae) in Costa Rica, representing the first example of a gall making Stigmella; Stigmella schinivora van Nieukerken, sp. n. reared from leafmines on Schinus terebinthifolia (Anacardiaceae) in Argentina, Misiones; Stigmella costaricensis van Nieukerken & Nishida, sp. n. and Stigmella intronia van Nieukerken & Nishida, sp. n. each from a single specimen collected the same night in Costa Rica, Parque Nacional Chirripó; Stigmella molinensis van Nieukerken & Snyers, sp. n. reared from leafmines on Salix humboldtiana, Peru, Lima, the first Neotropical species of the Stigmella salicis group sensu stricto; Ozadelpha van Nieukerken, gen. n. with type species Ozadelpha conostegiae van Nieukerken & Nishida, sp. n., reared from leafmines on Conostegia oerstediana (Melastomataceae) from Costa Rica; Neotrifurcula van Nieukerken, gen. n. with type species Neotrifurcula gielisorum van Nieukerken, sp. n. from Chile; Hesperolyra van Nieukerken, gen. n.. with type species Fomoria diskusi Puplesis & Robinson, 2000; Hesperolyra saopaulensis van Nieukerken, sp. n., reared from an unidentified Myrtaceae, Sao Paulo, Brasil; and Acalyptris janzeni van Nieukerken & Nishida, sp. n. from Costa Rica, Guanacaste. Five new combinations are made: Ozadelpha ovata (Puplesis & Robinson, 2000), comb. n. and Ozadelpha guajavae (Puplesis & Diškus, 2002), comb. n., Hesperolyra diskusi (Puplesis & Robinson, 2000), comb. n., Hesperolyra molybditis (Zeller, 1877), comb. n. and Hesperolyra repanda (Puplesis & Diškus, 2002), comb. n. Three specimens are briefly described, but left unnamed: Ozadelpha specimen EvN4680, Neotrifurcula specimen EvN4504 and Neotrifurcula specimen RH2. PMID:27917037

Do apolipoprotein E genotype and educational attainment predict the rate of cognitive decline in normal aging? A 12-year follow-up of the Maastricht Aging Study.

PubMed

Van Gerven, Pascal W M; Van Boxtel, Martin P J; Ausems, Eleonora E B; Bekers, Otto; Jolles, Jelle

2012-07-01

We investigated suspected longitudinal interaction effects of apolipoprotein E (APOE) genotype and educational attainment on cognitive decline in normal aging. Our sample consisted of 571 healthy, nondemented adults aged between 49 and 82 years. Linear mixed-models analyses were performed with four measurement time points: baseline, 3-year, 6-year, and 12-year follow-up. Covariates included age at baseline, sex, and self-perceived physical and mental health. Dependent measures were global cognitive functioning (Mini-Mental State Examination; Folstein, Folstein, & McHugh, 1975), Stroop performance (Stroop Color-Word Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006a), set-shifting performance (Concept Shifting Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006b), cognitive speed (Letter-Digit Substitution Test; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2006c), verbal learning (Verbal Learning Test: Sum of five trials; Van der Elst, Van Boxtel, Van Breukelen, & Jolles, 2005), and long-term memory (Verbal Learning Test: Delayed recall). We found only faint evidence that older, high-educated carriers of the APOE-ε4 allele (irrespective of zygosity) show a more pronounced decline than younger, low-educated carriers and noncarriers (irrespective of educational attainment). Moreover, this outcome was confined to concept-shifting performance and was especially observable between 6- and 12-year follow-ups. No protective effects of higher education were found on any of the six cognitive measures. We conclude that the combination of APOE-ε4 allele and high educational attainment may be a risk factor for accelerated cognitive decline in older age, as has been reported before, but only to a very limited extent. Moreover, we conclude that, within the cognitive reserve framework, education does not have significant protective power against age-related cognitive decline.

Vancomycin resistant Enterococcus spp. from crows and their environment in metropolitan Washington State, USA: Is there a correlation between VRE positive crows and the environment?

PubMed

Roberts, Marilyn C; No, David B; Marzluff, John M; Delap, Jack H; Turner, Robert

2016-10-15

Vancomycin-resistant enterococci [VRE] have been isolated from municipal, hospital and agricultural wastewater, recreational beaches, wild animals, birds and food animals around the world. In this study, American crows (Corvus brachyrhynchos) from sewage treatment plants (WWTP), dairy farms, and a large roost in a restored wetland with corresponding environmental samples were cultured for VRE. A total of 245 samples [156 crows, 89 environmental] were collected and screened for acquired vanA, vanB and/or intrinsic vanC1 genes. Samples were enriched overnight in BHI supplemented with 20μg/mL aztreonam, 4μg/mL vancomycin and plated on m-Enterococcus agar media supplemented with 6μg/mL vancomycin. Selected colonies were grown on BHI media supplemented with 18μg/mL vancomycin. Of these, 24.5% of the crow and 55% the environmental/cow samples were VRE positive as defined by Enterococcus spp. able to grow on media supplemented with 18μg/mL vancomycin. A total of 122 VRE isolates, 43 crow and 79 environmental isolates were screened, identified to species level using 16S sequencing and further characterized. Four vanA E. faecium and multiple vanC1 E. gallinarum were identified from crows isolated from three sites. E. faecium vanA and E. gallinarum vanC1 along with other Enterococcus spp. carrying vanA, vanB, vanC1 were isolated from three environments. All enterococci were multidrug resistant. Crows were more likely to carry vanA E. faecium than either the cow feces or wetland waters/soils. Comparing E. gallinarum vanC1 from crows and their environment would be useful in determining whether crows share VRE strains with their environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Wolf-bison interactions in Yellowstone National Park

USGS Publications Warehouse

Smith, Douglas W.; Mech, L. David; Meagher, Mary; Clark, Wendy E.; Jaffe, Rosemary; Phillips, Michael K.; Mack, John A.

2000-01-01

We studied interactions of reintroduced wolves (Canis lupus) with bison (Bison bison) in Yellowstone National Park. Only 2 of 41 wolves in this study had been exposed to bison before their translocation. Wolves were more successful killing elk (Cervus elaphus) than bison, and elk were more abundant than bison, so elk were the primary prey of wolves. Except for a lone emaciated bison calf killed by 8 1-year-old wolves 21 days after their release, the 1st documented kill occurred 25 months after wolves were released. Fourteen bison kills were documented from April 1995 through March 1999. All kills were made in late winter when bison were vulnerable because of poor condition or of bison that were injured or young. Wolves learned to kill bison and killed more bison where elk were absent or scarce. We predict that wolves that have learned to kill bison will kill them more regularly, at least in spring. The results of this study indicate how adaptable wolves are at killing prey species new to them.

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

Computer Simulation of the Effect of Pretreatment with Reversible Acetylcholinesterase Inhibitors on the Protection Against Soman Poisoning

DTIC Science & Technology

1993-12-01

dr. U.A. Th. Brinkmnan 31* Directeur van het Medisch Biologisch Laboratorium TNO Prof. dr. W.R.F. Notten 32 PML-TNO, Directeur; daarna reserve 33 PML...Generaal Personeel Ministerie van Defensie 8* Adviseur van het Prins Maurits Laboratorium TNO Chemnische Research Prof. dr. G. Dijkstra 9* lid van de

Alternative Fuels Data Center: Natural Gas Delivery Vans Support McShan

Science.gov Websites

FloristA> Natural Gas Delivery Vans Support McShan Florist to someone by E-mail Share Alternative Natural Gas Delivery Vans Support McShan Florist Watch how a Dallas, Texas, florist reduces emissions and saves money fueling delivery vans with compressed natural gas. For information about this project

Ex ante Implementatietoetsing van Beleid, Een Methodiek Gebaseerd op Synergie Tussen Risicomanagement en Verandermanagement (Ex Ante Test for Policy Implementation - A Method Based Upon Synergy Between Risk Management an Change Management)

DTIC Science & Technology

2006-12-01

ante implementatietoetsing van beleid Een methodiek gebaseerd op synergie tussen risicomnanagemnent en verandermanagemnent Datuni december 2006 Auteur (s...te analyseren. Het de resultaten van de interviews gebruikct bij de theorie van risicomanagement en project Verandermanagernent bij de de ontwikkehing...Opdrachtnummer Hoewel expliciet is gekeken naar voorbeelden van risico’s bij Datum december 2006 Auteur (s) PROGRAMMA PR03ECT drs. R.C.T. de Haas drs

Waardering en Analyse van Simulatieresultaten (Valuation and Analysis of Simulation Results)

DTIC Science & Technology

1991-12-01

is uit de tabel van de Students T-verdeling te halen . Deze wordt aangeduid met t,(v), waarin a de overschrijdingskans en v bet aantal vrijheidsgraden...2 vrijheidsgraden. Uit de tabol van de Student’s t-verdeling zija nu de kritieke waardon R, on R2 to halen zodanig dat P(t >R2 ) = i Wordt or eon...analyse van simnulatieresultaten - TDCnaK RAPPORTE1CENTRALE Frederikkazerne, Geb. 140 AD-A25 470van den Burchlaan 31AD-A25 470Telefoon: 070-3166394

Novel type of VanB2 teicoplanin-resistant hospital-associated Enterococcus faecium.

PubMed

Santona, Antonella; Paglietti, Bianca; Al-Qahtani, Ahmed A; Bohol, Marie Fe F; Senok, Abiola; Deligios, Massimo; Rubino, Salvatore; Al-Ahdal, Mohammed N

2014-08-01

Seven high-risk clones of vancomycin-resistant Enterococcus faecium (VREF) belonging to clonal complex 17 were identified using multilocus sequence typing (MLST) among clinical isolates from Saudi Arabia. Among these isolates, a new hospital-associated sequence type (ST795), VanB(2)-type teicoplanin-resistant strain was detected. Its unusual phenotype resulted from a new combination of mutations in the ddl, vanS and vanW genes, which confirmed the trend of evolution in VanB-type resistance. Furthermore, characteristics of adaptation and persistence in the hospital environment of ST795 were emphasised by the presence of genes and clusters recognised to be specific for hospital-associated VREF. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.209 - Rabies Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Rabies Vaccine, Killed Virus. 113.209... Killed Virus Vaccines § 113.209 Rabies Vaccine, Killed Virus. Rabies Vaccine (Killed Virus) shall be..., safe, and immunogenic shall be used for preparing the production seed virus for vaccine production. All...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.209 - Rabies Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Rabies Vaccine, Killed Virus. 113.209... Killed Virus Vaccines § 113.209 Rabies Vaccine, Killed Virus. Rabies Vaccine (Killed Virus) shall be..., safe, and immunogenic shall be used for preparing the production seed virus for vaccine production. All...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.209 - Rabies Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Rabies Vaccine, Killed Virus. 113.209... Killed Virus Vaccines § 113.209 Rabies Vaccine, Killed Virus. Rabies Vaccine (Killed Virus) shall be..., safe, and immunogenic shall be used for preparing the production seed virus for vaccine production. All...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.209 - Rabies Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Rabies Vaccine, Killed Virus. 113.209... Killed Virus Vaccines § 113.209 Rabies Vaccine, Killed Virus. Rabies Vaccine (Killed Virus) shall be..., safe, and immunogenic shall be used for preparing the production seed virus for vaccine production. All...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

78 FR 43063 - Drawbridge Operation Regulations; Arthur Kill, NY

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-19

... Regulations; Arthur Kill, NY AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from regulations... governing the operation of the Arthur Kill AK Railroad Bridge across Arthur Kill, mile 11.6, between Staten...) 366-9826. SUPPLEMENTARY INFORMATION: The AK Railroad Bridge, across Arthur Kill, mile 11.6, between...

From Attitudes to Actions: Predictors of Lion Killing by Maasai Warriors

PubMed Central

Dickman, Amy; Frank, Laurence

2017-01-01

Despite legal protection, deliberate killing by local people is one of the major threats to the conservation of lions and other large carnivores in Africa. Addressing this problem poses particular challenges, mainly because it is difficult to uncover illicit behavior. This article examined two groups of Maasai warriors: individuals who have killed African lions (Panthera leo) and those who have not. We conducted interviews to explore the relationship between attitudes, intentions and known lion killing behavior. Factor analysis and logistic regression revealed that lion killing was mainly determined by: (a) general attitudes toward lions, (b) engagement in traditional customs, (c) lion killing intentions to defend property, and (d) socio-cultural killing intentions. Our results indicated that general attitudes toward lions were the strongest predictor of lion killing behavior. Influencing attitudes to encourage pro-conservation behavior may help reduce killing. PMID:28135338

Competition between apex predators? Brown bears decrease wolf kill rate on two continents

PubMed Central

Ordiz, Andrés; Metz, Matthew C.; Milleret, Cyril; Wikenros, Camilla; Smith, Douglas W.; Stahler, Daniel R.; Kindberg, Jonas; MacNulty, Daniel R.; Wabakken, Petter; Swenson, Jon E.; Sand, Håkan

2017-01-01

Trophic interactions are a fundamental topic in ecology, but we know little about how competition between apex predators affects predation, the mechanism driving top-down forcing in ecosystems. We used long-term datasets from Scandinavia (Europe) and Yellowstone National Park (North America) to evaluate how grey wolf (Canis lupus) kill rate was affected by a sympatric apex predator, the brown bear (Ursus arctos). We used kill interval (i.e. the number of days between consecutive ungulate kills) as a proxy of kill rate. Although brown bears can monopolize wolf kills, we found no support in either study system for the common assumption that they cause wolves to kill more often. On the contrary, our results showed the opposite effect. In Scandinavia, wolf packs sympatric with brown bears killed less often than allopatric packs during both spring (after bear den emergence) and summer. Similarly, the presence of bears at wolf-killed ungulates was associated with wolves killing less often during summer in Yellowstone. The consistency in results between the two systems suggests that brown bear presence actually reduces wolf kill rate. Our results suggest that the influence of predation on lower trophic levels may depend on the composition of predator communities. PMID:28179516

In Vivo Fluorescence Confocal Microscopy to Investigate the Role of RhoC in Inflammatory Breast Cancer

DTIC Science & Technology

2005-11-01

5084. 6. Colpaert CG, Vermeulen PB, Benoy I, Soubry A, van Roy F, van Beest P, Goovaerts G, Dirix LY, van Dam P, Fox SB, Harris AL, van MarckEA...small GTPases, RhoA and RhoC, is associ- inflammatory breast cancer. Clin Exp Metastasis 2002, ated with tumor progression in ovarian carcinoma. Lab

Design and mechanistic study of a novel gold nanocluster-based drug delivery system.

PubMed

Li, Qinzhen; Pan, Yiting; Chen, Tiankai; Du, Yuanxin; Ge, Honghua; Zhang, Buchang; Xie, Jianping; Yu, Haizhu; Zhu, Manzhou

2018-05-22

Chemically-triggered drug delivery systems (DDSs) have been extensively studied as they do not require specialized equipment to deliver the drug and can deeply penetrate human tissue. However, their syntheses are complicated and they tend to be cytotoxic, which restricts their clinical utility. In this work, the self-regulated drug loading and release capabilities of peptide-protected gold nanoclusters (Pep-Au NCs) are investigated using vancomycin (Van) as the model drug. Gold nanoclusters (Au NCs) coated with a custom-designed pentapeptide are synthesized as drug delivery nanocarriers and loaded with Van - a spontaneous process reliant on the specific binding between Van and the custom-designed peptide. The Van-loaded Au NCs show comparable antimicrobial activity with Van on its own, and the number of Van released by the Pep-Au NCs is found to be proportional to the amount of bacteria present. The controlled nature of the Van release is very encouraging, and predominantly due to the stronger binding affinity of Van with bacteria than that with Au NCs. In addition, these fluorescent Au NCs could also be used to construct temperature sensors, which enable the in vitro and in vivo bioimaging.

Vanilla mosaic virus isolates from French Polynesia and the Cook Islands are Dasheen mosaic virus strains that exclusively infect vanilla.

PubMed

Farreyrol, K; Pearson, M N; Grisoni, M; Cohen, D; Beck, D

2006-05-01

Sequence was determined for the coat protein (CP) gene and 3' non-translated region (3'NTR) of two vanilla mosaic virus (VanMV) isolates from Vanilla tahitensis, respectively from the Cook Islands (VanMV-CI) and French Polynesia (VanMV-FP). Both viruses displayed distinctive features in the N-terminal region of their CPs; for VanMV-CI, a 16-amino-acid deletion including the aphid transmission-related DAG motif, and for VanMV-FP, a stretch of GTN repeats that putatively belongs to the class of natively unfolded proteins. VanMV-FP CP also has a novel DVG motif in place of the DAG motif, and an uncommon Q//V protease cleavage site. The sequences were compared to a range of Dasheen mosaic virus (DsMV) strains and to potyviruses infecting orchids. Identity was low to DsMV strains across the entire CP coding region and across the 3'NTR, but high across the CP core and the CI-6K2-NIa region. In accordance with current ICTV criteria for species demarcation within the family Potyviridae, VanMV-CI and VanMV-FP are strains of DsMV that exclusively infect vanilla.

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.206 - Wart Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Wart Vaccine, Killed Virus. 113.206... Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be prepared... content as prescribed in § 113.200(f). (d) Potency and efficacy. The efficacy of wart vaccine has been...

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bovine Virus Diarrhea Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.215 Bovine Virus Diarrhea Vaccine, Killed Virus. Bovine Virus Diarrhea Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Bovine Virus Diarrhea Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.215 Bovine Virus Diarrhea Vaccine, Killed Virus. Bovine Virus Diarrhea Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.206 - Wart Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Wart Vaccine, Killed Virus. 113.206... Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be prepared... content as prescribed in § 113.200(f). (d) Potency and efficacy. The efficacy of wart vaccine has been...

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Bovine Virus Diarrhea Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.215 Bovine Virus Diarrhea Vaccine, Killed Virus. Bovine Virus Diarrhea Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed virus...

9 CFR 113.206 - Wart Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Wart Vaccine, Killed Virus. 113.206... Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be prepared... content as prescribed in § 113.200(f). (d) Potency and efficacy. The efficacy of wart vaccine has been...

9 CFR 113.206 - Wart Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Wart Vaccine, Killed Virus. 113.206... Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be prepared... content as prescribed in § 113.200(f). (d) Potency and efficacy. The efficacy of wart vaccine has been...

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Bovine Virus Diarrhea Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.215 Bovine Virus Diarrhea Vaccine, Killed Virus. Bovine Virus Diarrhea Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed virus...

9 CFR 113.206 - Wart Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Wart Vaccine, Killed Virus. 113.206... Killed Virus Vaccines § 113.206 Wart Vaccine, Killed Virus. Wart Vaccine, Killed Virus, shall be prepared... content as prescribed in § 113.200(f). (d) Potency and efficacy. The efficacy of wart vaccine has been...

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Bovine Virus Diarrhea Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.215 Bovine Virus Diarrhea Vaccine, Killed Virus. Bovine Virus Diarrhea Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed virus...

Kill operation requires thorough analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abel, L.W.

1995-05-15

Full control of a blowout well requires a properly designed post-capping kill operation because failures in regaining well control usually occur during the kill operation, not during capping. Capping (the installation of pressure control or diverter equipment on the wellhead) is generally very reliable in gaining control of a blowout well. The following techniques are some of the viable means of killing blowout wells once the capping assemblies are in place: direct shut in of the flow; bullheading; momentum kill; volumetric control for migration of fluids or lubrication after migration ceases; and dynamic kills (friction-based dynamic kills or mass flowmore » rate kills) The objective of most post-capping operations is to stop the flow and put the well under hydrostatic control. The means of killing a blowout once capping assemblies are in place should be chosen with care to avoid problems such as cratering, equipment failure, and underground blowouts. The particular circumstances and well integrity will dictate which kill method will be the most viable. Each of these five methods are explained.« less

Van der waals forces on thin liquid films in capillary tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herdt, G.C.; Swanson, L.W.

1993-10-01

A theory of the van der Waals attraction between a thin liquid films and a capillary tube is presented assuming the presence of a vapor-liquid interface. The model is based on the surface mode analysis method of van Kampen et al. Values for the van der Waals interaction energy per unit area were calculated for liquid films of pentane on a gold substrate assuming a thin liquid film. Results indicate that the effect of capillary curvature on the van der Waals interaction increases as the ratio of the liquid film thickness to the capillary radius is increased. This trend ismore » consistent with predictions based on the Hamaker theory. Deviations from results based on the Hamaker theory are easily explained in terms of retardation of the van der Waals interaction. Because the effect of capillary curvature increases in the regime where retardation effects become important, curvature effects constitute a small correction to the van der Waals forces in a capillary tube.« less

Activity of telithromycin (HMR 3647) against anaerobic bacteria compared to those of eight other agents by time-kill methodology.

PubMed

Credito, K L; Ednie, L M; Jacobs, M R; Appelbaum, P C

1999-08-01

Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO(2). Macrolide-azalide-ketolide MICs were 0.004 to 32.0 microg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC /=99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred.

Accuracy of the VITEK 2 System To Detect Glycopeptide Resistance in Enterococci

PubMed Central

van den Braak, Nicole; Goessens, Wil; van Belkum, Alex; Verbrugh, Henri A.; Endtz, Hubert P.

2001-01-01

We evaluated the accuracy of the VITEK 2 fully automated system to detect and identify glycopeptide-resistant enterococci (GRE) compared to a reference agar dilution method. The sensitivity of vancomycin susceptibility testing with VITEK 2 for the detection of vanA, vanB, and vanC1 strains was 100%. The sensitivity of vancomycin susceptibility testing of vanC2 strains was 77%. The sensitivity of teicoplanin susceptibility testing of vanA strains was 90%. Of 80 vanC enterococci, 78 (98%) were correctly identified by VITEK 2 as Enterococcus gallinarum/Enterococcus casseliflavus. Since the identification and susceptibility data are produced within 3 and 8 h, respectively, VITEK 2 appears a fast and reliable method for detection of GRE in microbiology laboratories. PMID:11136798

First complete genome sequence of vanilla mosaic strain of Dasheen mosaic virus isolated from the Cook Islands.

PubMed

Puli'uvea, Christopher; Khan, Subuhi; Chang, Wee-Leong; Valmonte, Gardette; Pearson, Michael N; Higgins, Colleen M

2017-02-01

We present the first complete genome of vanilla mosaic virus (VanMV). The VanMV genomic structure is consistent with that of a potyvirus, containing a single open reading frame (ORF) encoding a polyprotein of 3139 amino acids. Motif analyses indicate the polyprotein can be cleaved into the expected ten individual proteins; other recognised potyvirus motifs are also present. As expected, the VanMV genome shows high sequence similarity to the published Dasheen mosaic virus (DsMV) genome sequences; comparisons with DsMV continue to support VanMV as a vanilla infecting strain of DsMV. Phylogenetic analyses indicate that VanMV and DsMV share a common ancestor, with VanMV having the closest relationship with DsMV strains from the South Pacific.

Killing spinors and related symmetries in six dimensions

NASA Astrophysics Data System (ADS)

Batista, Carlos

2016-03-01

Benefiting from the index spinorial formalism, the Killing spinor equation is integrated in six-dimensional spacetimes. The integrability conditions for the existence of a Killing spinor are worked out and the Killing spinors are classified into two algebraic types; in the first type the scalar curvature of the spacetime must be negative, while in the second type the spacetime must be an Einstein manifold. In addition, the equations that define Killing-Yano (KY) and closed conformal Killing-Yano (CCKY) tensors are expressed in the index notation and, as consequence, all nonvanishing KY and CCKY tensors that can be generated from a Killing spinor are made explicit.

Identification of VanN-type vancomycin resistance in an Enterococcus faecium isolate from chicken meat in Japan.

PubMed

Nomura, Takahiro; Tanimoto, Koichi; Shibayama, Keigo; Arakawa, Yoshichika; Fujimoto, Shuhei; Ike, Yasuyoshi; Tomita, Haruyoshi

2012-12-01

Five VanN-type vancomycin-resistant Enterococcus faecium strains were isolated from a sample of domestic chicken meat in Japan. All isolates showed low-level resistance to vancomycin (MIC, 12 mg/liter) and had the same pulsed-field gel electrophoresis profile. The vancomycin resistance was encoded on a large plasmid (160 kbp) and was expressed constitutively. The VanN-type resistance operon was identical to the first resistance operon to be reported, with the exception of a 1-bp deletion in vanT(N) and a 1-bp substitution in vanS(N).

Review of Gasteruption Latreille (Hymenoptera, Gasteruptiidae) from Iran and Turkey, with the description of 15 new species

PubMed Central

van Achterberg, Cornelis; Talebi, Ali Asghar

2014-01-01

Abstract The genus Gasteruption Latreille, 1796 (Hymenoptera: Evanioidea: Gasteruptiidae: Gasteruptiinae) from North Iran and Turkey is revised, keyed and fully illustrated for the first time. In total 36 species are treated of which 33 are recorded from Turkey and 23 from Iran. Fifteen species are new for science: Gasteruption aciculatum van Achterberg, sp. n., Gasteruption agrenum van Achterberg, sp. n., Gasteruption brevibasale van Achterberg & Saure, sp. n., Gasteruption coriacoxale van Achterberg, sp. n., Gasteruption flavimarginatum van Achterberg, sp. n., Gasteruption heminitidum van Achterberg, sp. n., Gasteruption henseni van Achterberg, sp. n., Gasteruption ischnolaimum van Achterberg, sp. n., Gasteruption nigrapiculatum van Achterberg, sp. n., Gasteruption paglianoi van Achterberg & Saure, sp. n., Gasteruption pseudolaticeps van Achterberg, sp. n., Gasteruption punctifrons van Achterberg, sp. n., Gasteruption schmideggeri van Achterberg & Saure, sp. n., Gasteruption scorteum van Achterberg, sp. n. and Gasteruption smitorum van Achterberg, sp. n. Twenty-one species are reported new for Turkey and 16 species new for Iran. Fifteen new synonyms are proposed: Foenus terrestris Tournier, 1877, Gasteruption trifossulatum Kieffer, 1904, and Gasteruption ignoratum Kieffer, 1912, of Gasteruption caucasicum (Guérin-Méneville, 1844); Gasteruption daisyi Alekseev, 1993, of Gasteruption dolichoderum Schletterer, 1889; Gasteruption assectator var. nitidulum Schletterer, 1885, of Gasteruption freyi (Tournier, 1877); Gasteruption schossmannae Madl, 1987, of Gasteruption hastator (Fabricius, 1804); Gasteryption fallaciosum Semenov, 1892, Gasteruption dubiosum Semenov, 1892 and Gasteruption obsoletum Semenov, 1892, of Gasteruption insidiosum Semenov, 1892; Gasteryption schewyrewi Semenov, 1892, of Gasteruption jaculator (Linnaeus, 1758); Gasteruption floreum Szépligeti, 1903, of Gasteruption lugubre Schletterer, 1889; Gasteruption trichotomma Kieffer, 1904, and Gasteruption palaestinum Pic, 1916, of Gasteruption merceti Kieffer, 1904; Gasteryption foveiceps Semenov, 1892, of Gasteruption nigrescens Schletterer, 1885, and Gasteruption libanense Pic, 1916, of Gasteruption syriacum Szépligeti, 1903. Gasteruption lugubre Schletterer, 1889, is recognised as a valid species. Lectotypes are designated for Ichneumon assectator Linnaeus, 1758; Ichneumon jaculator Linnaeus, 1758; Foenus terrestris Tournier, 1877; Foenus freyi Tournier, 1877; Foenus nigripes Tournier, 1877; Foenus goberti Tournier, 1877; Foenus granulithorax Tournier, 1877; Foenus minutus Tournier, 1877; Foenus borealis Thomson, 1883; Faenus diversipes Abeille de Perrin, 1879; Foenus rugulosus Abeille de Perrin, 1879; Faenus obliteratus Abeille de Perrin, 1879; Faenus undulatum Abeille de Perrin, 1879; Faenus variolosus Abeille de Perrin, 1879; Gasteruption distinguendum Schletterer, 1885; Gasteruption laeviceps Schletterer, 1885; Gasteruption thomsonii Schletterer, 1885; Gasteruption foveolatum Schletterer, 1889; Gasteruption sowae Schletterer, 1901; Gasteruption foveolum Szépligeti, 1903; Gasteruption floreum Szépligeti, 1903; Gasteruption caudatum Szépligeti, 1903; Gasteruption syriacum Szépligeti, 1903; Gasteruption merceti Kieffer, 1904 and Gasteruption ignoratum Kieffer, 1912. A neotype is designated for Gasteruption tournieri Schletterer, 1885. PMID:25561849

Competition between apex predators? Brown bears decrease wolf kill rate on two continents.

PubMed

Tallian, Aimee; Ordiz, Andrés; Metz, Matthew C; Milleret, Cyril; Wikenros, Camilla; Smith, Douglas W; Stahler, Daniel R; Kindberg, Jonas; MacNulty, Daniel R; Wabakken, Petter; Swenson, Jon E; Sand, Håkan

2017-02-08

Trophic interactions are a fundamental topic in ecology, but we know little about how competition between apex predators affects predation, the mechanism driving top-down forcing in ecosystems. We used long-term datasets from Scandinavia (Europe) and Yellowstone National Park (North America) to evaluate how grey wolf ( Canis lupus ) kill rate was affected by a sympatric apex predator, the brown bear ( Ursus arctos ). We used kill interval (i.e. the number of days between consecutive ungulate kills) as a proxy of kill rate. Although brown bears can monopolize wolf kills, we found no support in either study system for the common assumption that they cause wolves to kill more often. On the contrary, our results showed the opposite effect. In Scandinavia, wolf packs sympatric with brown bears killed less often than allopatric packs during both spring (after bear den emergence) and summer. Similarly, the presence of bears at wolf-killed ungulates was associated with wolves killing less often during summer in Yellowstone. The consistency in results between the two systems suggests that brown bear presence actually reduces wolf kill rate. Our results suggest that the influence of predation on lower trophic levels may depend on the composition of predator communities. © 2017 The Authors.

Where and How Wolves (Canis lupus) Kill Beavers (Castor canadensis).

PubMed

Gable, Thomas D; Windels, Steve K; Bruggink, John G; Homkes, Austin T

2016-01-01

Beavers (Castor canadensis) can be a significant prey item for wolves (Canis lupus) in boreal ecosystems due to their abundance and vulnerability on land. How wolves hunt beavers in these systems is largely unknown, however, because observing predation is challenging. We inferred how wolves hunt beavers by identifying kill sites using clusters of locations from GPS-collared wolves in Voyageurs National Park, Minnesota. We identified 22 sites where wolves from 4 different packs killed beavers. We classified these kill sites into 8 categories based on the beaver-habitat type near which each kill occurred. Seasonal variation existed in types of kill sites as 7 of 12 (58%) kills in the spring occurred at sites below dams and on shorelines, and 8 of 10 (80%) kills in the fall occurred near feeding trails and canals. From these kill sites we deduced that the typical hunting strategy has 3 components: 1) waiting near areas of high beaver use (e.g., feeding trails) until a beaver comes near shore or ashore, 2) using vegetation, the dam, or other habitat features for concealment, and 3) immediately attacking the beaver, or ambushing the beaver by cutting off access to water. By identifying kill sites and inferring hunting behavior we have provided the most complete description available of how and where wolves hunt and kill beavers.

Building a mechanistic understanding of predation with GPS-based movement data.

PubMed

Merrill, Evelyn; Sand, Håkan; Zimmermann, Barbara; McPhee, Heather; Webb, Nathan; Hebblewhite, Mark; Wabakken, Petter; Frair, Jacqueline L

2010-07-27

Quantifying kill rates and sources of variation in kill rates remains an important challenge in linking predators to their prey. We address current approaches to using global positioning system (GPS)-based movement data for quantifying key predation components of large carnivores. We review approaches to identify kill sites from GPS movement data as a means to estimate kill rates and address advantages of using GPS-based data over past approaches. Despite considerable progress, modelling the probability that a cluster of GPS points is a kill site is no substitute for field visits, but can guide our field efforts. Once kill sites are identified, time spent at a kill site (handling time) and time between kills (killing time) can be determined. We show how statistical models can be used to investigate the influence of factors such as animal characteristics (e.g. age, sex, group size) and landscape features on either handling time or killing efficiency. If we know the prey densities along paths to a kill, we can quantify the 'attack success' parameter in functional response models directly. Problems remain in incorporating the behavioural complexity derived from GPS movement paths into functional response models, particularly in multi-prey systems, but we believe that exploring the details of GPS movement data has put us on the right path.

Revision of the family Chalcididae (Hymenoptera, Chalcidoidea) from Vietnam, with the description of 13 new species

PubMed Central

Narendran, T. C.; van Achterberg, Cornelis

2016-01-01

Abstract A total of 16 genera and 68 species of Chalcididae of Vietnam are taxonomically treated. Thirteen new species are described; the remaining 55 species are keyed, redescribed or provided with a diagnosis. Among these 37 species and eleven genera are recorded for the first time from Vietnam. The thirteen new species are: Antrocephalus neogalleriae Narendran & van Achterberg, sp. n.; Brachymeria neowiebesina Narendran & van Achterberg, sp. n., Brachymeria semirusula Narendran & van Achterberg, sp. n., Dirhinus neoclaviger Narendran & van Achterberg, sp. n., Epitranus narendrani van Achterberg, sp. n., Epitranus neonigriceps Narendran & van Achterberg, sp. n., Heydoniella vietnamensis Narendran & van Achterberg, sp. n., Megachalcis vietnamicus Narendran & van Achterberg, sp. n., Notaspidium vietnamicum Narendran & van Achterberg, sp. n., Oxycoryphe neotenax Narendran & van Achterberg, sp. n., Sthulapada neopadata Narendran & van Achterberg, sp. n., Sthulapada vietnamensis Narendran & van Achterberg, sp. n., and Tanycoryphus masii Narendran & van Achterberg, sp. n. The newly recorded genera are: Antrocephalus Kirby, 1883; Haltichella Spinola, 1811; Heydoniella Narendran, 2003; Hockeria Walker, 1834; Kriechbaumerella Dalla Torre, 1894; Notaspidium Dalla Torre, 1897; Oxycoryphe Kriechbaumer, 1894; Psilochalcis Kieffer, 1904; Sthulapada Narendran, 1989; Tanycorphus Cameron, 1905, and Trigonura Sichel, 1865. The following known species are recorded for the first time from Vietnam: Antrocephalus decipiens (Masi, 1929); Antrocephalus lugubris (Masi, 1932); Antrocephalus maculipennis (Cameron, 1905); Antrocephalus nasutus (Holmgren, 1869); Antrocephalus sepyra (Walker, 1846); Antrocephalus validicornis (Holmgren, 1868); Brachymeria alternipes (Walker, 1871); Brachymeria aurea (Girault, 1915); Brachymeria coxodentata Joseph, Narendran & Joy, 1972; Brachymeria euploeae (Westwood, 1837); Brachymeria hime Habu, 1960; Brachymeria jambolana Gahan, 1942; Brachymeria kamijoi Habu, 1960; Brachymeria lugubris (Walker, 1871); Brachymeria marmonti (Girault, 1924); Brachymeria minuta (Linnaeus, 1767); Brachymeria scutellocarinata Joseph, Narendran & Joy, 1972; Brachymeria shansiensis Habu, 1961; Brachymeria taiwana (Matsumura, 1910); Dirhinus anthracia Walker, 1846; Dirhinus claviger Bouček & Narendran, 1981; Epitranus albipennis Walker, 1874; Epitranus ater Bouček, 1982; Epitranus gauldi Bouček, 1982; Epitranus oxytelus Bouček, 1982; Epitranus ramnathi (Mani & Dubey, 1973); Haltichella delhensis Roy & Farooqi, 1984; Haltichella nipponensis Habu, 1960; Hockeria bangalorica Narendran, 1989; Hockeria guptai Narendran, 1989; Kriechbaumerella ayyari (Gahan, 1919); Kriechbaumerella cordigaster Roy & Farooqi, 1984; Kriechbaumerella destructor (Waterston, 1922); Kriechbaumerella nepalensis Narendran, 1989; Oxycoryphe scutellatus Narendran, 1989; Psilochalcis carinigena (Cameron, 1907), and Trigonura luzonensis Narendran, 1987. Brachymeria calopeplae Joseph, Narendran & Joy, 1972, is treated as a valid species. PMID:27110185

Investigating the Effect of van Hiele Phase-Based Instruction on Pre-Service Teachers' Geometric Thinking

ERIC Educational Resources Information Center

Armah, Robert Benjamin; Cofie, Primrose Otokonor; Okpoti, Christopher Adjei

2018-01-01

This study investigated the effect of van Hiele Phase-based Instruction (VHPI) on Ghanaian Pre-service Teachers' (PTs') geometric thinking in terms of the van Hiele Levels. A pre-test post-test quasi-experimental design was employed. There were 75 PTs each in the experimental group and the control group. Van Hiele Geometry Test (VHGT) was…

Experimental Testing of a Van De Graaff Generator as an Electromagnetic Pulse Generator

DTIC Science & Technology

2016-07-01

EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR THESIS...protection in the United States AFIT-ENP-MS-16-S-075 EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR...RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-16-S-075 EXPERIMENTAL TESTING OF A VAN DE GRAAFF GENERATOR AS AN ELECTROMAGNETIC PULSE GENERATOR

78 FR 47817 - Parts and Accessories Necessary for Safe Operation; Application for an Exemption From Van Hool N...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-06

....V. and Coach USA AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT. ACTION: Notice of... exemption from Van Hool N.V. and Coach USA (Van Hool/Coach USA) to allow the use of double deck motorcoaches..., Van Hool/Coach USA is requesting an exemption that would allow the use of sleeper berths that comply...

Alternating current impedance spectroscopic analysis of biofunctionalized vertically-aligned silica nanospring surface for biosensor applications

NASA Astrophysics Data System (ADS)

Timalsina, Yukta P.

In this dissertation, a process of vertically-aligned (silica) nanosprings (VANS) based biosensor development is presented. Alternating current (AC) impedance spectroscopy has been used to analyze sensor response as a function of saline phosphate (SP) buffer and biological solutions. The sensor is a parallel plate capacitor consisting of two glass substrates coated with indium tin oxide (ITO), where the VANS [or randomly-aligned nanosprings (RANS)] grown on one substrate serve as the dielectric spacer layer. The response of a VANS device as a function of ionic concentration in SP buffer was examined and an equivalent circuit model was developed. The results demonstrated that VANS sensors exhibited greater sensitivity to the changes in SP concentration relative to the ITO sensors, which serve as controls. The biofunctionalized VANS surface via physisorption and the cross-linker method demonstrates the repeatability, specificity, and selectivity of the binding. The physisorption of biotinylated immunoglobulin G (B-IgG) onto the VANS surface simplifies the whole sensing procedure for the detection of glucose oxidase, since the avidin-conjugated glucose oxidase (Av-GOx) can directly be immobilized on the B-IgG. The cross linker method involves the covalent attachment of antibodies onto the functionalized VANS surface via imine bond. The experiments revealed that the VANS sensor response is solely the result of the interaction of target molecule i.e. mouse IgG with the probe layer, i.e. goat antimouse IgG (GalphaM IgG). It was determined that VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls above 100 Hz, which indicates that the addition of biomolecules inhibits the diffusion of ions and changes the effective dielectric response of the VANS via biomolecular polarization. The study of ionic transport in nanosprings suggested that conductance follows a scaling law. It was demonstrated that a VANS-based device exhibits a greater magnitude of change relative to the RANS device below 10 kHz, which has equivalent property of the ITO controls. This dissertation demonstrates the potential for VANS as a novel nanomaterial platform for the development of highly sensitive, selective, low cost, and label free biosensors.

Mathematical foundations of the dendritic growth models.

PubMed

Villacorta, José A; Castro, Jorge; Negredo, Pilar; Avendaño, Carlos

2007-11-01

At present two growth models describe successfully the distribution of size and topological complexity in populations of dendritic trees with considerable accuracy and simplicity, the BE model (Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997) and the S model (Van Pelt and Verwer in Bull. Math. Biol. 48:197-211, 1986). This paper discusses the mathematical basis of these models and analyzes quantitatively the relationship between the BE model and the S model assumed in the literature by developing a new explicit equation describing the BES model (a dendritic growth model integrating the features of both preceding models; Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997). In numerous studies it is implicitly presupposed that the S model is conditionally linked to the BE model (Granato and Van Pelt in Brain Res. Dev. Brain Res. 142:223-227, 2003; Uylings and Van Pelt in Network 13:397-414, 2002; Van Pelt, Dityatev and Uylings in J. Comp. Neurol. 387:325-340, 1997; Van Pelt and Schierwagen in Math. Biosci. 188:147-155, 2004; Van Pelt and Uylings in Network. 13:261-281, 2002; Van Pelt, Van Ooyen and Uylings in Modeling Dendritic Geometry and the Development of Nerve Connections, pp 179, 2000). In this paper we prove the non-exactness of this assumption, quantify involved errors and determine the conditions under which the BE and S models can be separately used instead of the BES model, which is more exact but considerably more difficult to apply. This study leads to a novel expression describing the BE model in an analytical closed form, much more efficient than the traditional iterative equation (Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997) in many neuronal classes. Finally we propose a new algorithm in order to obtain the values of the parameters of the BE model when this growth model is matched to experimental data, and discuss its advantages and improvements over the more commonly used procedures.

Evaluation of risk factors for vancomycin-induced nephrotoxicity.

PubMed

Park, So Jin; Lim, Na Ri; Park, Hyo Jung; Yang, Jae Wook; Kim, Min-Ji; Kim, Kyunga; In, Yong Won; Lee, Young Mee

2018-05-09

Background Vancomycin is a glycopeptide antibiotic of choice for the treatment of serious infections caused by multi-resistant Gram-positive bacteria. However, vancomycin-associated nephrotoxicity (VAN) often limits its use. Previous data suggested a few risk factors of VAN, including higher mean vancomycin trough level, higher daily doses, old age, long duration of vancomycin therapy, and concomitant nephrotoxins. Objective To evaluate the incidence and risk factors of VAN and determine whether higher vancomycin trough concentrations were associated with a greater risk for VAN. Settings A retrospective, observational, single-center study at the 1960-bed university-affiliated tertiary care hospital (Samsung Medical Center), Seoul, Korea. Method A retrospective analysis of adult patients who received vancomycin parenterally in a tertiary care medical center from March 1, 2013 to June 30, 2013 was performed. We excluded patients with a baseline serum creatinine level > 2 mg/dL and those who had a history of end-stage renal disease and dialysis at baseline. The clinical characteristics were compared between patients with nephrotoxicity and those without nephrotoxicity to identify the risk factors associated with VAN. Main outcome measure Incidence of VAN and VAN-associated risk factors were analyzed. Results Of the 315 vancomycin-treated patients, nephrotoxicity occurred in 15.2% of the patients. In multivariate analysis, higher vancomycin trough concentrations of > 20 mg∕L (OR 9.57, 95% CI 2.49-36.83, p < 0.01) and intensive care unit (ICU) residence (OR 2.86, 95% CI 1.41-5.82, p < 0.01) were independently associated with VAN. Conclusion Our findings suggest that higher vancomycin trough levels and ICU residence might be associated with a greater risk for VAN. More careful monitoring of vancomycin serum trough levels and patient status might facilitate the timely prevention of VAN.

Genetics Home Reference: dihydropyrimidine dehydrogenase deficiency

MedlinePlus

... NG, Bakker HD, Meinsma R, Van Lenthe H, De Abreu RA, Smeitink JA, Kayserili H, Apak MY, ... 9. Review. Citation on PubMed van Kuilenburg AB, De Abreu RA, van Gennip AH. Pharmacogenetic and clinical ...

Projective mappings and dimensions of vector spaces of three types of Killing-Yano tensors on pseudo Riemannian manifolds of constant curvature

NASA Astrophysics Data System (ADS)

Mikeš, Josef; Stepanov, Sergey; Hinterleitner, Irena

2012-07-01

In our paper we have determined the dimension of the space of conformal Killing-Yano tensors and the dimensions of its two subspaces of closed conformal Killing-Yano and Killing-Yano tensors on pseudo Riemannian manifolds of constant curvature. This result is a generalization of well known results on sharp upper bounds of the dimensions of the vector spaces of conformal Killing-Yano, Killing-Yano and concircular vector fields on pseudo Riemannian manifolds of constant curvature.

Building Cultural Capability for Full-Spectrum Operations

DTIC Science & Technology

2008-01-01

Mol, Born, Willemsen, & Van der Molen , 2005; Caligiuri & Day, 2000). In addition to these broad traits, antecedents to cross-cultural competence...510-517. 18 Mol, S. T., Born, M. P., Willemsen, M. E., & Van Der Molen , H. T. (2005). Predicting expatriate job performance for selection purposes: A...et al., 2003). In addition, self-regulation has been shown to be critical for adjustment (Matsumoto et al., 2003; van Oudenhoven, Mol, & Van der Zee

Selective Perception for Robot Driving

DTIC Science & Technology

1992-05-01

models are theories of human cognitive activity during driving. Van der Molen and Botticher recently reviewed several of these models [ van der Molen 871...how to represent driving knowledge, how to perceive traffic situations, or how to process information to obtain actions. Van der Molen and Botticher...attempted to compare the operations of various models objectively on the same task [Rothengatter 88, van der Molen 87], but the models could be

Quality of Life for Adults with Asthma in a Military Setting

DTIC Science & Technology

1998-05-01

Tilley, Havstead, & Zoratti, 1997). More recently, van der Molen , et al. (1997) conducted a study comparing discriminative aspects of two generic...Symptom Management Faculty Group, UCSF. (1994). IMAGE: Journal of Nursing Scholarship, 26(4), 272-276. van der Molen , T., Postma, D., Schreuers, A...the most important (Earwood, 1996, Rutten- Van Molken, Van Doorslaer, & Rutten, 1992). Purpose of the Study When patients clarify their perceptions of

Rater Biases in Genetically Informative Research Designs: Comment on Bartels, Boomsma, Hudziak, van Beijsterveldt, and van den Oord (2007)

ERIC Educational Resources Information Center

Hoyt, William T.

2007-01-01

Rater biases are of interest to behavior genetic researchers, who often use ratings data as a basis for studying heritability. Inclusion of multiple raters for each sibling pair (M. Bartels, D. I. Boomsma, J. J. Hudziak, T. C. E. M. van Beijsterveldt, & E. J. C. G. van den Oord, 2007) is a promising strategy for controlling bias variance and may…

Application of Diffusion Monte Carlo to Materials Dominated by van der Waals Interactions

DOE PAGES

Benali, Anouar; Shulenburger, Luke; Romero, Nichols A.; ...

2014-06-12

Van der Waals forces are notoriously difficult to account for from first principles. We perform extensive calculation to assess the usefulness and validity of diffusion quantum Monte Carlo when applied to van der Waals forces. We present results for noble gas solids and clusters - archetypical van der Waals dominated assemblies, as well as a relevant pi-pi stacking supramolecular complex: DNA + intercalating anti-cancer drug Ellipticine.

Psychological traits underlying different killing methods among Malaysian male murderers.

PubMed

Kamaluddin, Mohammad Rahim; Shariff, Nadiah Syariani; Nurfarliza, Siti; Othman, Azizah; Ismail, Khaidzir H; Mat Saat, Geshina Ayu

2014-04-01

Murder is the most notorious crime that violates religious, social and cultural norms. Examining the types and number of different killing methods that used are pivotal in a murder case. However, the psychological traits underlying specific and multiple killing methods are still understudied. The present study attempts to fill this gap in knowledge by identifying the underlying psychological traits of different killing methods among Malaysian murderers. The study adapted an observational cross-sectional methodology using a guided self-administered questionnaire for data collection. The sampling frame consisted of 71 Malaysian male murderers from 11 Malaysian prisons who were selected using purposive sampling method. The participants were also asked to provide the types and number of different killing methods used to kill their respective victims. An independent sample t-test was performed to establish the mean score difference of psychological traits between the murderers who used single and multiple types of killing methods. Kruskal-Wallis tests were carried out to ascertain the psychological trait differences between specific types of killing methods. The results suggest that specific psychological traits underlie the type and number of different killing methods used during murder. The majority (88.7%) of murderers used a single method of killing. Multiple methods of killing was evident in 'premeditated' murder compared to 'passion' murder, and revenge was a common motive. Examples of multiple methods are combinations of stabbing and strangulation or slashing and physical force. An exception was premeditated murder committed with shooting, when it was usually a single method, attributed to the high lethality of firearms. Shooting was also notable when the motive was financial gain or related to drug dealing. Murderers who used multiple killing methods were more aggressive and sadistic than those who used a single killing method. Those who used multiple methods or slashing also displayed a higher level of minimisation traits. Despite its limitations, this study has provided some light on the underlying psychological traits of different killing methods which is useful in the field of criminology.

Present self-represented futures of value are a reason for the wrongness of killing.

PubMed

Parsons, S J

2002-06-01

In Marquis's recent paper he has not satisfactorily shown that killing does not adversely affect the victim's present self-represented desires for their future. Marquis is correct in believing life and death are distinct, but living and dying are not. In fact, to use a well-known saying, "the second we are born we start to die". During the process of dying, whether it be long as in over our lifetime or short as in as we are being killed, there comes a point when the present realistic desires we have we know will never be satisfied. This is why killing can be wrong. This would imply killing an unconscious person, infant, or fetus cannot be wrong. But such killing can be wrong, despite the person killed not experiencing the desire not to be killed as he was dying. Killing can be wrong because others can have a present self-represented desire for that person not to be killed to have been killed. If this line of reasoning is correct, then the "best interests" principle often applied to life and death considerations regarding unconscious persons, infants, and fetuses, is invalid, as such human beings do not have present desires. All that matters is what relevant others rationally desire, after being informed of the facts and the consequences, for that unconscious person, infant or fetus.

Where and How Wolves (Canis lupus) Kill Beavers (Castor canadensis)

PubMed Central

Gable, Thomas D.; Windels, Steve K.; Bruggink, John G.; Homkes, Austin T.

2016-01-01

Beavers (Castor canadensis) can be a significant prey item for wolves (Canis lupus) in boreal ecosystems due to their abundance and vulnerability on land. How wolves hunt beavers in these systems is largely unknown, however, because observing predation is challenging. We inferred how wolves hunt beavers by identifying kill sites using clusters of locations from GPS-collared wolves in Voyageurs National Park, Minnesota. We identified 22 sites where wolves from 4 different packs killed beavers. We classified these kill sites into 8 categories based on the beaver-habitat type near which each kill occurred. Seasonal variation existed in types of kill sites as 7 of 12 (58%) kills in the spring occurred at sites below dams and on shorelines, and 8 of 10 (80%) kills in the fall occurred near feeding trails and canals. From these kill sites we deduced that the typical hunting strategy has 3 components: 1) waiting near areas of high beaver use (e.g., feeding trails) until a beaver comes near shore or ashore, 2) using vegetation, the dam, or other habitat features for concealment, and 3) immediately attacking the beaver, or ambushing the beaver by cutting off access to water. By identifying kill sites and inferring hunting behavior we have provided the most complete description available of how and where wolves hunt and kill beavers. PMID:27992441

Broadening the future of value account of the wrongness of killing.

PubMed

Di Nucci, Ezio

2015-11-01

On Don Marquis's future of value account of the wrongness of killing, 'what makes it wrong to kill those individuals we all believe it is wrong to kill, is that killing them deprives them of their future of value'. Marquis has recently argued for a narrow interpretation of his future of value account of the wrongness of killing and against the broad interpretation that I had put forward in response to Carson Strong. In this article I argue that the narrow view is problematic because it violates some basic principles of equality and because it allows for some of the very killing that Marquis sets out to condemn; further, I argue that the chief reason why Marquis chooses the narrow view over the broad view-namely that the broad view would take the killing of some non-human animals to be also wrong-should rather be considered a welcome upshot of the broad view.

Killing(-Yano) tensors in string theory

NASA Astrophysics Data System (ADS)

Chervonyi, Yuri; Lunin, Oleg

2015-09-01

We construct the Killing(-Yano) tensors for a large class of charged black holes in higher dimensions and study general properties of such tensors, in particular, their behavior under string dualities. Killing(-Yano) tensors encode the symmetries beyond isometries, which lead to insights into dynamics of particles and fields on a given geometry by providing a set of conserved quantities. By analyzing the eigenvalues of the Killing tensor, we provide a prescription for constructing several conserved quantities starting from a single object, and we demonstrate that Killing tensors in higher dimensions are always associated with ellipsoidal coordinates. We also determine the transformations of the Killing(-Yano) tensors under string dualities, and find the unique modification of the Killing-Yano equation consistent with these symmetries. These results are used to construct the explicit form of the Killing(-Yano) tensors for the Myers-Perry black hole in arbitrary number of dimensions and for its charged version.

Multiresolution texture models for brain tumor segmentation in MRI.

PubMed

Iftekharuddin, Khan M; Ahmed, Shaheen; Hossen, Jakir

2011-01-01

In this study we discuss different types of texture features such as Fractal Dimension (FD) and Multifractional Brownian Motion (mBm) for estimating random structures and varying appearance of brain tissues and tumors in magnetic resonance images (MRI). We use different selection techniques including KullBack - Leibler Divergence (KLD) for ranking different texture and intensity features. We then exploit graph cut, self organizing maps (SOM) and expectation maximization (EM) techniques to fuse selected features for brain tumors segmentation in multimodality T1, T2, and FLAIR MRI. We use different similarity metrics to evaluate quality and robustness of these selected features for tumor segmentation in MRI for real pediatric patients. We also demonstrate a non-patient-specific automated tumor prediction scheme by using improved AdaBoost classification based on these image features.

50th Annual Scientific Meeting of the British Society for Haematology.

PubMed

Thomas, Angela E

2010-08-01

The 50th Annual Scientific Meeting of the British Society for Haematology was notable, not only for its golden anniversary, but also because it coincided with the eruption of the Icelandic volcano, Eyjafjallajökull, and the ensuing travel chaos. In total, 28 speakers from overseas were unable to reach Edinburgh, including a significant number of British speakers who were stranded. However, owing to the superb efforts of the conference organisers and Edinburgh International Conference Centre staff, teleconferencing equipment was installed and all speakers were contacted and able to give their talks on time. The program, consisting of simultaneous sessions and plenary lectures, covered not only recent advances in clinical and laboratory hematology, but also reflected on the contribution of British hematology to the international arena over the past 50 years.

Observations of Eyjafjallajökull eruption's plume at Potenza EARLINET station

NASA Astrophysics Data System (ADS)

Mona, Lucia; Amodeo, Aldo; Boselli, Antonella; Cornacchia, Carmela; D'Amico, Guiseppe; Giunta, Aldo; Madonna, Fabio; Pappalardo, Gelsomina

2010-05-01

Eyjafjallajökull is one of the smallest glacier in Iceland. After seismic activity recorded during December 2009, a first eruption started on 20 March, between 22:30 and 23:30 UT. After a brief stop, a new phase of the Eyjafjallajökull eruption started around midnight on April 14, where melt penetrated its way to the central crater beneath the glacier. An eruption plume was observed in the early morning on 14 April. Ash loaded eruption plume rose to more than 8 km height, deflected to the East by westerly winds. Eruptive activity continued in the following days until 23 April with variable maximum height (between 8 and 2 km a.s.l.). Until 27 April, a plume is always visible in proximity of the volcano. On 15 April, the eruption plume reaches continental Europe with closure of airspace over large part of Northern Europe. In the following days, airspace was closed also in some regions of Southern Europe. On 15 April, 10:00 UT CNR-IMAA, Potenza distributed an alert to EARLINET stations informing about a large amount of ash is directing towards North-West of Europe. Even if EARLINET is not an operational, but research oriented, network, almost all the EARLINET stations followed the event performing measurements whenever weather conditions allow it. Because of their proximity to the source, England and Scandinavian countries are of course the most involved in the transported ash arrival. Accordingly to the MetOffice forecasts, the ash plume would have to reach Central Europe on 16 April. The transport toward South was almost blocked by the Alps. A different scenario is forecasted by MetOffice for 20-21 April when the arrival of the volcanic plume is forecasted down to the Southern Italy. At CNR-IMAA, the atmospheric observatory (CIAO) followed the event by means of all available instruments, including EARLINET multi-wavelength lidars, cloud-radar, microwave profiler and AERONET sun-photometer. Low clouds and rain did not permit measurements over Potenza for the period starting from the distributed alert on 15 April until the evening of 19 April. Since 19 April, measurements were performed almost continuously, with breaks only for light rain and low clouds, until 22 April evening when intense rain started again. During the whole observation period aerosol content is not negligible in the free troposphere with sparse aerosols distributed between 3 and 8 km a.s.l. In addition thin layers are distinguishable in the reported temporal evolution at different times and altitudes (e.g. descending layer between 10 and 5 km on 21 April, 00:00 UT -14:00 UT). The most intense aerosol return above the PBL is observed on 20 April around 22:20 UT at about 4 km a.s.l. Ancillary information confirm the volcanic origin of the selected layer. Accordingly to DREAM forecast, no dust should be present over Italy for this day. HYSPLIT backtrajectories show that the observed layer comes from Northern Europe, probably from Iceland. In the following hours, the volcanic layer went down in altitude, mixing with the underlying local aerosol layer. ACKNOWLEDGMENTS The financial support for EARLINET by the European Commission under grant RICA-025991 is gratefully acknowledged. The authors thank NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT backtrajectory analysis, the Barcelona Supercomputing Center for DREAM forecasts, NASA for MODIS image and MetOffice for forecast of volcano plume dispersion.

[Mobile hospital -real time mobile telehealthcare system with ultrasound and CT van using high-speed satellite communication-].

PubMed

Takizawa, Masaomi; Miyashita, Toyohisa; Murase, Sumio; Kanda, Hirohito; Karaki, Yoshiaki; Yagi, Kazuo; Ohue, Toru

2003-01-01

A real-time telescreening system is developed to detect early diseases for rural area residents using two types of mobile vans with a portable satellite station. The system consists of a satellite communication system with 1.5Mbps of the JCSAT-1B satellite, a spiral CT van, an ultrasound imaging van with two video conference system, a DICOM server and a multicast communication unit. The video image and examination image data are transmitted from the van to hospitals and the university simultaneously. Physician in the hospital observes and interprets exam images from the van and watches the video images of the position of ultrasound transducer on screenee in the van. After the observation images, physician explains a results of the examination by the video conference system. Seventy lung CT screening and 203 ultrasound screening were done from March to June 2002. The trial of this real time screening suggested that rural residents are given better healthcare without visit to the hospital. And it will open the gateway to reduce the medical cost and medical divide between city area and rural area.

DdlN from Vancomycin-Producing Amycolatopsis orientalis C329.2 Is a VanA Homologue with d-Alanyl-d-Lactate Ligase Activity

PubMed Central

Marshall, C. Gary; Wright, Gerard D.

1998-01-01

Vancomycin-resistant enterococci acquire high-level resistance to glycopeptide antibiotics through the synthesis of peptidoglycan terminating in d-alanyl-d-lactate. A key enzyme in this process is a d-alanyl-d-alanine ligase homologue, VanA or VanB, which preferentially catalyzes the synthesis of the depsipeptide d-alanyl-d-lactate. We report the overexpression, purification, and enzymatic characterization of DdlN, a VanA and VanB homologue encoded by a gene of the vancomycin-producing organism Amycolatopsis orientalis C329.2. Evaluation of kinetic parameters for the synthesis of peptides and depsipeptides revealed a close relationship between VanA and DdlN in that depsipeptide formation was kinetically preferred at physiologic pH; however, the DdlN enzyme demonstrated a narrower substrate specificity and commensurately increased affinity for d-lactate in the C-terminal position over VanA. The results of these functional experiments also reinforce the results of previous studies that demonstrated that glycopeptide resistance enzymes from glycopeptide-producing bacteria are potential sources of resistance enzymes in clinically relevant bacteria. PMID:9791137

d-Ala-d-Ser VanN-Type Transferable Vancomycin Resistance in Enterococcus faecium▿

PubMed Central

Lebreton, François; Depardieu, Florence; Bourdon, Nancy; Fines-Guyon, Marguerite; Berger, Pierre; Camiade, Sabine; Leclercq, Roland; Courvalin, Patrice; Cattoir, Vincent

2011-01-01

Enterococcus faecium UCN71, isolated from a blood culture, was resistant to low levels of vancomycin (MIC, 16 μg/ml) but susceptible to teicoplanin (MIC, 0.5 μg/ml). No amplification was observed with primers specific for the previously described glycopeptide resistance ligase genes, but a PCR product corresponding to a gene called vanN was obtained using degenerate primers and was sequenced. The deduced VanN protein was related (65% identity) to the d-alanine:d-serine VanL ligase. The organization of the vanN gene cluster, determined using degenerate primers and by thermal asymmetric interlaced (TAIL)-PCR, was similar to that of the vanC operons. A single promoter upstream from the resistance operon was identified by rapid amplification of cDNA ends (RACE)-PCR. The presence of peptidoglycan precursors ending in d-serine and d,d-peptidase activities in the absence of vancomycin indicated constitutive expression of the resistance operon. VanN-type resistance was transferable by conjugation to E. faecium. This is the first report of transferable d-Ala-d-Ser-type resistance in E. faecium. PMID:21807981

Killing-Yano Symmetry in Supergravity Theories

NASA Astrophysics Data System (ADS)

Houri, Tsuyoshi

Killing-Yano symmetry has played an important role in the study of black hole physics. In supergravity theories, Killing-Yano symmetry is deformed by the presence of the fluxes which can be identified with skew-symmetric torsion. Therefore, we attempt to classify spacetimes admitting Killing-Yano symmetry with torsion. In particular, the classification problem of metrics admitting a principal Killing-Yano tensor with torsion is discussed.

Activity of Telithromycin (HMR 3647) against Anaerobic Bacteria Compared to Those of Eight Other Agents by Time-Kill Methodology†

PubMed Central

Credito, Kim L.; Ednie, Lois M.; Jacobs, Michael R.; Appelbaum, Peter C.

1999-01-01

Time-kill studies examined the activities of telithromycin (HMR 3647), erythromycin A, azithromycin, clarithromycin, roxithromycin, clindamycin, pristinamycin, amoxicillin-clavulanate, and metronidazole against 11 gram-positive and gram-negative anaerobic bacteria. Time-kill studies were carried out with the addition of Oxyrase in order to prevent the introduction of CO2. Macrolide-azalide-ketolide MICs were 0.004 to 32.0 μg/ml. Of the latter group, telithromycin had the lowest MICs, especially against non-Bacteroides fragilis group strains, followed by azithromycin, clarithromycin, erythromycin A, and roxithromycin. Clindamycin was active (MIC ≤ 2.0 μg/ml) against all anaerobes except Peptostreptococcus magnus and Bacteroides thetaiotaomicron, while pristinamycin MICs were 0.06 to 4.0 μg/ml. Amoxicillin-clavulanate had MICs of ≤1.0 μg/ml, while metronidazole was active (MICs, 0.03 to 2.0 μg/ml) against all except Propionibacterium acnes. After 48 h at twice the MIC, telithromycin was bactericidal (≥99.9% killing) against 6 strains, with 99% killing of 9 strains and 90% killing of 10 strains. After 24 h at twice the MIC, 90, 99, and 99.9% killing of nine, six, and three strains, respectively, occurred. Lower rates of killing were seen at earlier times. Similar kill kinetics relative to the MIC were seen with other macrolides. After 48 h at the MIC, clindamycin was bactericidal against 8 strains, with 99 and 90% killing of 9 and 10 strains, respectively. After 24 h, 90% killing of 10 strains occurred at the MIC. The kinetics of clindamycin were similar to those of pristinamycin. After 48 h at the MIC, amoxicillin-clavulanate showed 99.9% killing of seven strains, with 99% killing of eight strains and 90% killing of nine strains. At four times the MIC, metronidazole was bactericidal against 8 of 10 strains tested after 48 h and against all 10 strains after 24 h; after 12 h, 99% killing of all 10 strains occurred. PMID:10428930

Carbon stocks of trees killed by bark beetles and wildfire in the western United States

USGS Publications Warehouse

Hicke, Jeffrey A.; Meddens, Arjan J.H.; Allen, Craig D.; Kolden, Crystal A.

2013-01-01

Forests are major components of the carbon cycle, and disturbances are important influences of forest carbon. Our objective was to contribute to the understanding of forest carbon cycling by quantifying the amount of carbon in trees killed by two disturbance types, fires and bark beetles, in the western United States in recent decades. We combined existing spatial data sets of forest biomass, burn severity, and beetle-caused tree mortality to estimate the amount of aboveground and belowground carbon in killed trees across the region. We found that during 1984-2010, fires killed trees that contained 5-11 Tg C year-1 and during 1997-2010, beetles killed trees that contained 2-24 Tg C year-1, with more trees killed since 2000 than in earlier periods. Over their periods of record, amounts of carbon in trees killed by fires and by beetle outbreaks were similar, and together these disturbances killed trees representing 9% of the total tree carbon in western forests, a similar amount to harvesting. Fires killed more trees in lower-elevation forest types such as Douglas-fir than higher-elevation forest types, whereas bark beetle outbreaks also killed trees in higher-elevation forest types such as lodgepole pine and Engelmann spruce. Over 15% of the carbon in lodgepole pine and spruce/fir forest types was in trees killed by beetle outbreaks; other forest types had 5-10% of the carbon in killed trees. Our results document the importance of these natural disturbances in the carbon budget of the western United States.

Effects of Vegetation Structure on the Location of Lion Kill Sites in African Thicket.

PubMed

Davies, Andrew B; Tambling, Craig J; Kerley, Graham I H; Asner, Gregory P

2016-01-01

Predator-prey relationships are integral to ecosystem stability and functioning. These relationships are, however, difficult to maintain in protected areas where large predators are increasingly being reintroduced and confined. Where predators make kills has a profound influence on their role in ecosystems, but the relative importance of environmental variables in determining kill sites, and how these might vary across ecosystems is poorly known. We investigated kill sites for lions in South Africa's thicket biome, testing the importance of vegetation structure for kill site locations compared to other environmental variables. Kill sites were located over four years using GPS telemetry and compared to non-kill sites that had been occupied by lions, as well as to random sites within lion ranges. Measurements of 3D vegetation structure obtained from Light Detection and Ranging (LiDAR) were used to calculate the visible area (viewshed) around each site and, along with wind and moonlight data, used to compare kill sites between lion sexes, prey species and prey sexes. Viewshed area was the most important predictor of kill sites (sites in dense vegetation were twice as likely to be kill sites compared to open areas), followed by wind speed and, less so, moonlight. Kill sites for different prey species varied with vegetation structure, and male prey were killed when wind speeds were higher compared to female prey of the same species. Our results demonstrate that vegetation structure is an important component of predator-prey interactions, with varying effects across ecosystems. Such differences require consideration in terms of the ecological roles performed by predators, and in predator and prey conservation.

Patterns and Composition of Road-Killed Wildlife in Northwest Argentina.

PubMed

Cuyckens, Griet An Erica; Mochi, Lucía Sol; Vallejos, María; Perovic, Pablo Gastón; Biganzoli, Fernando

2016-11-01

Roads have important effects on wildlife, such as natural habitat fragmentation and degradation and direct killing of fauna, which leads to reductions in wildlife population size. We focused on a principal road in Northwest Argentina to test for the effect of seasonality and landscape features on the composition of road-killed wildlife. We conducted regularly scheduled road trips during the dry and wet seasons. We recorded the presence or absence of a vegetation curtain or hedge along the road. We measured land use by remote sensing in a 500 m buffer along the road. We compared the abundance of animals killed between seasons (dry and wet) for different taxonomic groups (mammals, birds and reptiles) and for different origins (domestic and native). We built linear mixed models to test the effect of landscape features on the abundance of killed animals. Two hundred and ninety-three individuals were killed, belonging to 35 species; 75.8 % were native and 24.2 % domestic species. The majority of animals killed were mid-sized mammals. More animals were killed during the dry season. The most important factors to explain the wildlife road-killing were the season and the proportion of agricultural landscape. The composition of the killed animals changed with the season. The proportion of agricultural landscape incremented the number of killed birds and mammals during both seasons, without affecting reptiles. The ratio of wild to domestic animals killed was dependent on the season. This study sets a precedent as the first in road ecology in Northwest Argentina and should be taken into account for road planning and regulation.

Firing a Weapon and Killing In Combat Are Associated with Suicidal Ideation in OEF/OIF Veterans

PubMed Central

Tripp, Jessica C.; McDevitt-Murphy, Meghan E.; Henschel, Aisling V.

2016-01-01

Objective Combat veterans are at risk for several adverse outcomes such as posttraumatic stress disorder (PTSD), depression, hazardous alcohol use, and most critically, suicidal behaviors. The high rate of suicide in veterans has been understood as a correlate of PTSD and depression, but it is possible that certain specific types of combat experiences may lead to suicidal behaviors. Acts committed by the veteran in the context of war such as killing may evoke a “moral injury,” which leads to thoughts of ending one’s life. Method The present exploratory research examined relationships between combat experiences and suicidal ideation (SI) and PTSD in a sample of 68 OEF/OIF veterans (91% male, mean age = 32.31 years) who had screened positive for alcohol misuse. We examined firing a weapon/killing in combat (Firing/Killing) and killing in combat (Killing) alone as predictors of (SI) and PTSD severity in both the full sample, and in analyses that examined men only. Results Firing/Killing were associated with SI for the full sample and men only, and Killing showed a trend towards significance in predicting SI. Hierarchical regression analyses suggested that Firing/Killing did not predict PTSD for the full sample or men only, but Killing was predictive of PTSD for both samples. Conclusions These results indicate that there may be differences in Firing/Killing and Killing alone in OEF/OIF veterans who screened positive for alcohol misuse. Thorough screening of combat experiences and addressing moral injury in returning combat veterans may help reduce high rates of suicide and PTSD. PMID:26460495

Patterns and Composition of Road-Killed Wildlife in Northwest Argentina

NASA Astrophysics Data System (ADS)

Cuyckens, Griet An Erica; Mochi, Lucía Sol; Vallejos, María; Perovic, Pablo Gastón; Biganzoli, Fernando

2016-11-01

Roads have important effects on wildlife, such as natural habitat fragmentation and degradation and direct killing of fauna, which leads to reductions in wildlife population size. We focused on a principal road in Northwest Argentina to test for the effect of seasonality and landscape features on the composition of road-killed wildlife. We conducted regularly scheduled road trips during the dry and wet seasons. We recorded the presence or absence of a vegetation curtain or hedge along the road. We measured land use by remote sensing in a 500 m buffer along the road. We compared the abundance of animals killed between seasons (dry and wet) for different taxonomic groups (mammals, birds and reptiles) and for different origins (domestic and native). We built linear mixed models to test the effect of landscape features on the abundance of killed animals. Two hundred and ninety-three individuals were killed, belonging to 35 species; 75.8 % were native and 24.2 % domestic species. The majority of animals killed were mid-sized mammals. More animals were killed during the dry season. The most important factors to explain the wildlife road-killing were the season and the proportion of agricultural landscape. The composition of the killed animals changed with the season. The proportion of agricultural landscape incremented the number of killed birds and mammals during both seasons, without affecting reptiles. The ratio of wild to domestic animals killed was dependent on the season. This study sets a precedent as the first in road ecology in Northwest Argentina and should be taken into account for road planning and regulation.

Winter wolf predation in a multiple ungulate prey system, Gates of the Arctic National Park, Alaska

USGS Publications Warehouse

Dale, Bruce W.; Adams, Layne G.; Bowyer, R. Terry; Carbyn, Ludwig N.; Fritts, Steven H.; Seip, Dale R.

1995-01-01

We investigated patterns of winter wolf predation, including prey selection, prey switching, kill rates, carcass utilization, and consumption rates for four wolf packs during three different study periods (March 1989, March 1990, and November 1990) in Gates of the Arctic National Park and Preserve, Alaska. Wolves killed predominantly caribou (165 caribou, seven moose, and five Dall sheep) even when moose and sheep were more abundant. Prey selection varied between study periods. More moose were killed in march 1989, a particularly deep snow year, and more sheep were killed in November 1990 than during other periods. Overall kill rates ranged from 0-8 days/ungulate killed (x̅ = 2.0, SD = 1.6) and did not vary between study periods.  Pack size and species killed explained significant variation in the length of time intervals between kills. Although caribou density varied nearly 40-fold between pack territories, it had little influence on predation characteristics except at low densities, when kill rates may have declined. Caribou distribution had marked effects on wolf predation rate.

Resonance oscillations of nonreciprocal long-range van der Waals forces between atoms in electromagnetic fields

NASA Astrophysics Data System (ADS)

Sherkunov, Yury

2018-03-01

We study theoretically the van der Waals interaction between two atoms out of equilibrium with an isotropic electromagnetic field. We demonstrate that at large interatomic separations, the van der Waals forces are resonant, spatially oscillating, and nonreciprocal due to resonance absorption and emission of virtual photons. We suggest that the van der Waals forces can be controlled and manipulated by tuning the spectrum of artificially created random light.

Storings analyse Ten Behoeve van het Materieelverzorgingsplan (Failure Analysis for the Maintenance Plan)

DTIC Science & Technology

1990-05-01

oporachtnemer verwezen naar de ’Algemone Voorwaarden voor Onderzoeks- opdrachten TNO’. dan wet de betreflende terzake fijasen partlijen gesloten * 11 ...ixvulling van het onderhoudsschema 9 2.4 Invulling van het onderhoudsschema in de praktijk 14 2.5 Gonclusies 16 3 STORINGSANALYSES 18 3.1 ’Failure mode...nnfd- en subgroep (dit is een opdeling van bet systeem naar functioneel sanienhangende delen). Pa gina 9 - Het onderhoudsniveau waar jedere

Implication of Two-Coupled Differential Van der Pol Duffing Oscillator in Weak Signal Detection

NASA Astrophysics Data System (ADS)

Peng, Hang-hang; Xu, Xue-mei; Yang, Bing-chu; Yin, Lin-zi

2016-04-01

The principle of the Van der Pol Duffing oscillator for state transition and for determining critical value is described, which has been studied to indicate that the application of the Van der Pol Duffing oscillator in weak signal detection is feasible. On the basis of this principle, an improved two-coupled differential Van der Pol Duffing oscillator is proposed which can identify signals under any frequency and ameliorate signal-to-noise ratio (SNR). The analytical methods of the proposed model and the construction of the proposed oscillator are introduced in detail. Numerical experiments on the properties of the proposed oscillator compared with those of the Van der Pol Duffing oscillator are carried out. Our numerical simulations have confirmed the analytical treatment. The results demonstrate that this novel oscillator has better detection performance than the Van der Pol Duffing oscillator.

van Manen's method and reduction in a phenomenological hermeneutic study.

PubMed

Heinonen, Kristiina

2015-03-01

To describe van Manen's method and concept of reduction in a study that used a phenomenological hermeneutic approach. Nurse researchers have used van Manen's method in different ways. Participants' lifeworlds are described in depth, but descriptions of reduction have been brief. The literature and knowledge review and manual search of research articles. Databases Web Science, PubMed, CINAHL and PsycINFO, without applying a time period, to identify uses of van Manen's method. This paper shows how van Manen's method has been used in nursing research and gives some examples of van Manen's reduction. Reduction enables us to conduct in-depth phenomenological hermeneutic research and understand people's lifeworlds. As there are many variations in adapting reduction, it is complex and confusing. This paper contributes to the discussion of phenomenology, hermeneutic study and reduction. It opens up reduction as a method for researchers to exploit.

Scaling laws for van der Waals interactions in nanostructured materials.

PubMed

Gobre, Vivekanand V; Tkatchenko, Alexandre

2013-01-01

Van der Waals interactions have a fundamental role in biology, physics and chemistry, in particular in the self-assembly and the ensuing function of nanostructured materials. Here we utilize an efficient microscopic method to demonstrate that van der Waals interactions in nanomaterials act at distances greater than typically assumed, and can be characterized by different scaling laws depending on the dimensionality and size of the system. Specifically, we study the behaviour of van der Waals interactions in single-layer and multilayer graphene, fullerenes of varying size, single-wall carbon nanotubes and graphene nanoribbons. As a function of nanostructure size, the van der Waals coefficients follow unusual trends for all of the considered systems, and deviate significantly from the conventionally employed pairwise-additive picture. We propose that the peculiar van der Waals interactions in nanostructured materials could be exploited to control their self-assembly.

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

NASA Astrophysics Data System (ADS)

Lee, Shinbuhm; MacManus-Driscoll, Judith L.

2017-04-01

This review provides the design principles to develop new nanoionic applications using vertically aligned nanostructured (VAN) thin films, incorporating two phases which self-assemble in one film. Tunable nanoionics has attracted great attention for energy and device applications, such as ion batteries, solid oxide fuel cells, catalysts, memories, and neuromorphic devices. Among many proposed device architectures, VAN films have strong potential for nanoionic applications since they show enhanced ionic conductivity and tunability. Here, we will review the recent progress on state-of-the-art nanoionic applications, which have been realized by using VAN films. In many VAN systems made by the inclusion of an oxygen ionic insulator, it is found that ions flow through the vertical heterointerfaces. The observation is consistent with structural incompatibility at the vertical heteroepitaxial interfaces resulting in oxygen deficiency in one of the phases and hence to oxygen ion conducting pathways. In other VAN systems where one of the phases is an ionic conductor, ions flow much faster within the ionic conducting phase than within the corresponding plain film. The improved ionic conduction coincides with much improved crystallinity in the ionically conducting nanocolumnar phase, induced by use of the VAN structure. Furthermore, for both cases Joule heating effects induced by localized ionic current flow also play a role for enhanced ionic conductivity. Nanocolumn stoichiometry and strain are other important parameters for tuning ionic conductivity in VAN films. Finally, double-layered VAN film architectures are discussed from the perspective of stabilizing VAN structures which would be less stable and hence less perfect when grown on standard substrates.

Martin Van Buren National Historic Site transportation analysis report

DOT National Transportation Integrated Search

2010-10-01

The Volpe Transportation Systems Center (Volpe Center) is providing transportation support to Martin Van Buren National Historic Site's (NHS) first General Management Plan (GMP), which will be complete in 2010 or 2011. Currently, Martin Van Buren NHS...

The Dramatic Methods of Hans van Dam.

ERIC Educational Resources Information Center

van de Water, Manon

1994-01-01

Interprets for the American reader the untranslated dramatic methods of Hans van Dam, a leading drama theorist in the Netherlands. Discusses the functions of drama as a method, closed dramatic methods, open dramatic methods, and applying van Dam's methods. (SR)

78 FR 37270 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-20

... (IA) Thomas M. Harris (MI) Paul M. Hinkson (TN) Ellie L. Murphree (AL) Michael P. Passmore (FL) Wendell S. Sehen (OH) Gary E. Valentine (OH) Kevin W. Van Arsdol (CO) Charles Van Dyke (WI) Harlon C. Van...

Serum killing of Ureaplasma parvum shows serovar-determined susceptibility for normal individuals and common variable immuno-deficiency patients.

PubMed

Beeton, Michael L; Daha, Mohamed R; El-Shanawany, Tariq; Jolles, Stephen R; Kotecha, Sailesh; Spiller, O Brad

2012-02-01

Many Gram-negative bacteria, unlike Gram-positive, are directly lysed by complement. Ureaplasma can cause septic arthritis and meningitis in immunocompromised individuals and induce premature birth. Ureaplasma has no cell wall, cannot be Gram-stain classified and its serum susceptibility is unknown. Survival of Ureaplasma serovars (SV) 1, 3, 6 and 14 (collectively Ureaplasma parvum) were measured following incubation with normal or immunoglobulin-deficient patient serum (relative to heat-inactivated controls). Blocking monoclonal anti-C1q antibody and depletion of calcium, immunoglobulins, or lectins were used to determine the complement pathway responsible for killing. Eighty-three percent of normal sera killed SV1, 67% killed SV6 and 25% killed SV14; greater killing correlating to strong immunoblot identification of anti-Ureaplasma antibodies; killing was abrogated following ProteinA removal of IgG1. All normal sera killed SV3 in a C1q-dependent fashion, irrespective of immunoblot identification of anti-Ureaplasma antibodies; SV3 killing was unaffected by total IgG removal by ProteinG, where complement activity was retained. Only one of four common variable immunodeficient (CVID) patient sera failed to kill SV3, despite profound IgM and IgG deficiency for all; however, killing of SV3 and SV1 was restored with therapeutic intravenous immunoglobulin therapy. Only the classical complement pathway mediated Ureaplasma-cidal activity, sometimes in the absence of observable immunoblot reactive bands. Copyright © 2011 Elsevier GmbH. All rights reserved.

High vancomycin MICs within the susceptible range in Staphylococcus aureus bacteraemia isolates are associated with increased cell wall thickness and reduced intracellular killing by human phagocytes.

PubMed

Falcón, Rocío; Martínez, Alba; Albert, Eliseo; Madrid, Silvia; Oltra, Rosa; Giménez, Estela; Soriano, Mario; Vinuesa, Víctor; Gozalbo, Daniel; Gil, María Luisa; Navarro, David

2016-05-01

Vancomycin minimum inhibitory concentrations (MICs) at the upper end of the susceptible range for Staphylococcus aureus have been associated with poor clinical outcomes of bloodstream infections. We tested the hypothesis that high vancomycin MICs in S. aureus bacteraemia isolates are associated with increased cell wall thickness and suboptimal bacterial internalisation or lysis by human phagocytes. In total, 95 isolates were evaluated. Original vancomycin MICs were determined by Etest. The susceptibility of S. aureus isolates to killing by phagocytes was assessed in a human whole blood assay. Internalisation of bacterial cells by phagocytes was investigated by flow cytometry. Cell wall thickness was evaluated by transmission electron microscopy. Genotypic analysis of S. aureus isolates was performed using a DNA microarray system. Vancomycin MICs were significantly higher (P=0.006) in isolates that were killed suboptimally (killing index <60%) compared with those killed efficiently (killing index >70%) and tended to correlate inversely (P=0.08) with the killing indices. Isolates in both killing groups were internalised by human neutrophils and monocytes with comparable efficiency. The cell wall was significantly thicker (P=0.03) in isolates in the low killing group. No genotypic differences were found between the isolates in both killing groups. In summary, high vancomycin MICs in S. aureus bacteraemia isolates were associated with increased cell wall thickness and reduced intracellular killing by phagocytes. Copyright © 2016 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Toward an Operational Definition of Cross-Cultural Competence from the Literature

DTIC Science & Technology

2008-01-01

Journal of Applied Psychology, 73, 410-420. Mol, S. T., Born, M. P., Willemsen, M. E., & Van Der Molen , H. T. (2005). Predicting expatriate job...decision-making processes (Ang, Van Dyne, Koh, & Ng, 2004; Ang, Van Dyne, & Koh, 2007). Because the CQ has demonstrated validity and covers the...empirical foundation. U.S. Army Research Institute for the Behavioral and Social Sciences, Study Report 2008-1. Arlington, VA: ARI. Ang, S., Van Dyne, L

A Design Procedure for Minimizing Propeller-Induced Vibration in Hull Structural Elements.

DTIC Science & Technology

1979-09-01

Propeller," 12th International Towing Tank Conference, Rome, 1969. 46. Van Manen , J. D., "The Effect of Cavitation on the Interaction Be- tween Propeller...The wake, when determined in absence of the propeller, is called the nominal wake field. Van Oossanen [8) points out that it is becoming...wire anemometer and the laser-Doppler anomometer. These are discussed briefly in a paper by van Gent and van Oossanen [11. 4. Estimate Longitudinal

Who Do We Deploy for Psychological Operations: A Function Profile for TPT Members

DTIC Science & Technology

2008-01-01

doet onderzoek om de ontwikkeling v’an PSYOPS in Nederland te ondersteunen. Een eerste stap, in het goed voorbereiden en uitvoeren van PSYOPS is het...bezit. De focus van het huidige project ligt op de selectiemethode van mensen die PSYOPS functies gaan vervullen. Naast Nederland zijn er ook andere NAVO...deze interviews kwam naar voren dat verschillende landen kampen met dezelfde problemen als Nederland wat betreft de selectie van het PSYOPS personeel

Beslisbevoegdheden van de Uitgestegen Soldaat. Deel B: Verbetering van Situational Awareness Met Behulp van de Soldier Digital Assistant in een Gesimuleerde Omgeving (Authority and Responsbility of the Dismounted Soldier. Part B. Improving the Situational Awareness using the Soldier Digital Assistant in a Simulated Environment)

DTIC Science & Technology

2007-04-01

Dergelijke omngevingen zijn tot op heden vrijwel uitsluitend gebruikt voor training en onderwijs , maar slechts zeer sporadisch voor wetenschappelijk...Onderstaande instanties/personen ontvangen een volledig exemplaar van het rapport. 1 DMO/SC-DR&D standaard inclusief digitale versie bijgeleverd op cd

Militaire Toepassingen Van Adaptieve Optiek (Military Applications of Adaptive Optics)

DTIC Science & Technology

2006-09-01

dat op dit moment met de beschikbare theorie mogelijk is. Een ander interessant aspect is de mate waarin de turbulentie effecten het jam patroon...systemen In WEAG studie JP8. 11 is aangetoond dat in theorie adaptieve technieken een verbetering van de prestaties van een DIRCM systeem kunnen...Molenaar; Theorie van de laserscintillometer; TNO repot PHL 1978-16 (1978). TNO-rapport I TNO-DV 2006 A336 35/35 6 Ondertekening Den Haag, september 2006

Kwalificate/Classificatie van Explosieve Stoffen en Munitie. Rapport 2. Testontwikkeling (Qualification/Classification Explosive Materials and Munition. 2. Test Development)

DTIC Science & Technology

1992-11-01

beschermkap van het apparaat af te halen , waardoor bij een eventuele ontsteking het energetisch materiaal (al dan niet brandend) weg kan springen. Tevens...TNO-DefensieonderzoekPr TN TNO-rapport Kwalificatielclassificatie van explosieve stoffen ~ PML 1992-68 en munitief Rapport ]I: Testontwikkeling...rapport Kwalificatielclassificatie van explosieve stoffen PML 1992-68 en munitie Rapport f1: Testontwikkeling november 1992 ~~- ExorrIaar no:- 1ýMI

In vitro cytotoxicity of galvanically coupled magnesium-titanium particles on human osteosarcoma SAOS2 cells: A potential cancer therapy.

PubMed

Kim, Jua; Gilbert, Jeremy L

2018-04-10

Osteosarcoma is a malignant bone cancer that occurs mostly in children and young adults. This study investigated the cytotoxicity of Mg and Mg-Ti microparticles to human osteosarcoma cells. Osteosarcoma cells were killed in a dosage-dependent manner when cells, with a cell seeding density of 30,000 cells/cm 2 , were cultured with 0 to 2500 µg/mL of Mg or Mg-Ti in cell culture media for 24-72 h. Mg-Ti killed cells more effectively, where 1250 µg/mL of Mg-Ti killed cells completely by 24 h, while 2500 µg/mL of Mg killed nearly all cells, but not all. Killing due to particle corrosion occurred mostly during the first 24 h, and so the percent cell viability between 24 and 72 h showed not much variability. However, the measurement of live and dead cell numbers, over the timeframe of 24-72 h, showed more insight, such as cell recovery. If particle concentrations were low, the number of live cells increased after 24 h, indicating cell proliferation. If particle concentrations were high, the number of live cells either remained steady or decreased, indicating cell quiescence or continued killing, respectively. Increase in the number of dead cells also indicated killing, while plateau meant discontinued killing. In addition, repeated killing of recovered cells exhibited the same dose-dependent killing profile as the initial experiment, implying little development of cell resistance to treatment. These results, together, show that osteosarcoma cells are susceptible to killing by way of exposure to corroding particles, showing highly effective killing using the galvanic couple of Mg-Ti. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 Wiley Periodicals, Inc.

Effects of Vegetation Structure on the Location of Lion Kill Sites in African Thicket

PubMed Central

Davies, Andrew B.; Tambling, Craig J.; Kerley, Graham I. H.; Asner, Gregory P.

2016-01-01

Predator-prey relationships are integral to ecosystem stability and functioning. These relationships are, however, difficult to maintain in protected areas where large predators are increasingly being reintroduced and confined. Where predators make kills has a profound influence on their role in ecosystems, but the relative importance of environmental variables in determining kill sites, and how these might vary across ecosystems is poorly known. We investigated kill sites for lions in South Africa’s thicket biome, testing the importance of vegetation structure for kill site locations compared to other environmental variables. Kill sites were located over four years using GPS telemetry and compared to non-kill sites that had been occupied by lions, as well as to random sites within lion ranges. Measurements of 3D vegetation structure obtained from Light Detection and Ranging (LiDAR) were used to calculate the visible area (viewshed) around each site and, along with wind and moonlight data, used to compare kill sites between lion sexes, prey species and prey sexes. Viewshed area was the most important predictor of kill sites (sites in dense vegetation were twice as likely to be kill sites compared to open areas), followed by wind speed and, less so, moonlight. Kill sites for different prey species varied with vegetation structure, and male prey were killed when wind speeds were higher compared to female prey of the same species. Our results demonstrate that vegetation structure is an important component of predator-prey interactions, with varying effects across ecosystems. Such differences require consideration in terms of the ecological roles performed by predators, and in predator and prey conservation. PMID:26910832

Grizzly bear predation rates on caribou calves in northeastern Alaska

USGS Publications Warehouse

Young, Donald D.; McCabe, Thomas R.

1997-01-01

During June 1993 and 1994, 11 radiocollared and 7 unmarked grizzly bears (Ursus arctos) were monitored visually (observation) from fixed-wing aircraft to document predation on calves of the Porcupine Caribou (Rangifer tarandus) Herd (PCH) in northeastern Alaska. Twenty-six (72%) grizzly bear observations were completed (???60 min) successfully (median duration = 180 min; ??95% CI = 136-181 min; range = 67-189 min) and 10 were discontinued (duration ???24 min) due to disturbance to the bear, or unfavorable weather conditions. Of the 26 successfully completed observations, 15 (58%) included predatory activity (encounter) directed at caribou calves and 8 (31%) included kills. Of 32 encounters, 9 resulted in kills, for a success rate of 28%. The median duration of encounters was 1 minute (??95% CI = 1-2 min; range = 1-6 min; n = 32;), and the median time spent at a kill was 14 minutes (??95% CI = 9-23 min; range = 6-56 min; n = 9). Sows with young (n = 4) killed more frequently (75%; P = 0.0178) than barren sows, boars, and consorting pairs combined (17%; n = 18). Estimated kill rate was highest for sows with young (6.3 kills/bear/day; n = 4), followed by barren sows (4.6 kills/bear/day; n = 5), boars (1.9 kills/bear/day; n = 5), and, finally, consorting pairs (1.0 kills/bear/day; n = 8). Estimated kill rate obtained via conventional radiotracking point surveys (4.8 kills/bear/day) was higher than that obtained via concurrent bear observations (3.1 kills/bear/day). Our research provides baseline estimates of predation rates by grizzly bears on caribou calves that will enhance the capability of wildlife professionals in managing populations of both predators and their prey.

Serine and alanine racemase activities of VanT: a protein necessary for vancomycin resistance in Enterococcus gallinarum BM4174.

PubMed

Arias, C A; Weisner, J; Blackburn, J M; Reynolds, P E

2000-07-01

Vancomycin resistance in Enterococcus gallinarum results from the production of UDP-MurNAc-pentapeptide[D-Ser]. VanT, a membrane-bound serine racemase, is one of three proteins essential for this resistance. To investigate the selectivity of racemization of L-Ser or L-Ala by VanT, a strain of Escherichia coli TKL-10 that requires D-Ala for growth at 42 degrees C was used as host for transformation experiments using plasmids containing the full-length vanT from Ent. gallinarum or the alanine racemase gene (alr) of Bacillus stearothermophilus: both plasmids were able to complement E. coli TKL-10 at 42 degrees C. No alanine or serine racemase activities were detected in the host strain E. coli TKL-10 grown at 30, 34 or 37 degrees C. Serine and alanine racemase activities were found almost exclusively (96%) in the membrane fraction of E. coli TKL-10/pCA4(vanT): the alanine racemase activity of VanT was 14% of the serine racemase activity in both E. coli TKL-10/pCA4(vanT) and E. coli XL-1 Blue/pCA4(vanT). Alanine racemase activity was present mainly (95%) in the cytoplasmic fraction of E. coli TKL-10/pJW40(alr), with a trace (1.6%) of serine racemase activity. Additionally, DNA encoding the soluble domain of VanT was cloned and expressed in E. coli M15 as a His-tagged polypeptide and purified: this polypeptide also exhibited both serine and alanine racemase activities; the latter was approximately 18% of the serine racemase activity, similar to that of the full-length, membrane-bound enzyme. N-terminal sequencing of the purified His-tagged polypeptide revealed a single amino acid sequence, indicating that the formation of heterodimers between subunits of His-tagged C-VanT and endogenous alanine racemases from E. coli was unlikely. The authors conclude that the membrane-bound serine racemase VanT also has alanine racemase activity but is able to racemize serine more efficiently than alanine, and that the cytoplasmic domain is responsible for the racemase activity.

Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

PubMed

Pilfold, Nicholas W; Derocher, Andrew E; Stirling, Ian; Richardson, Evan; Andriashek, Dennis

2012-01-01

Polar bears (Ursus maritimus) of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650) and hunting attempts on ringed seal (Pusa hispida) lairs (n=1396) observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. Polar bears primarily preyed on ringed seals (90.2%) while bearded seals (Erignathus barbatus) only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344) of the ringed seals killed, while their pups comprised 38.4% (132/344). Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344) of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121), and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78). The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2) =0.30, P=0.04), but was not correlated with the number of adult kills (P=0.37). Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

Multiple factors and processes involved in host cell killing by bacteriophage Mu: characterization and mapping.

PubMed

Waggoner, B T; Marrs, C F; Howe, M M; Pato, M L

1984-07-15

The regions of bacteriophage Mu involved in host cell killing were determined by infection of a lambda-immune host with 12 lambda pMu-transducing phages carrying different amounts of Mu DNA beginning at the left end. Infecting lambda pMu phages containing 5.0 (+/- 0.2) kb or less of the left end of Mu DNA did not kill the lambda-immune host, whereas lambda pMu containing 5.1 kb did kill, thus locating the right end of the kil gene between approximately 5.0 and 5.1 kb. For the Kil+ phages the extent of killing increased as the multiplicity of infection (m.o.i.) increased. In addition, killing was also affected by the presence of at least two other regions of Mu DNA: one, located between 5.1 and 5.8 kb, decreased the extent of killing; the other, located between 6.3 and 7.9 kb, greatly increased host cell killing. Killing was also assayed after lambda pMu infection of a lambda-immune host carrying a mini-Mu deleted for most of the B gene and the middle region of Mu DNA. Complementation of mini-Mu replication by infecting B+ lambda pMu phages resulted in killing of the lambda-immune, mini-Mu-containing host, regardless of the presence or absence of the Mu kil gene. The extent of host cell killing increased as the m.o.i. of the infecting lambda pMu increased, and was further enhanced by both the presence of the kil gene and the region located between 6.3 and 7.9 kb. These distinct processes of kil-mediated killing in the absence of replication and non-kil-mediated killing in the presence of replication were also observed after induction of replication-deficient and kil mutant prophages, respectively.

77 FR 62533 - Agency Information Collection Activities; Proposed Collection, Comments Requested; Revision of a...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-15

... DEPARTMENT OF JUSTICE Federal Bureau of Investigation [OMB Number 1110-0009] Agency Information...: Law Enforcement Officers Killed and Assaulted Program; Analysis of Officer Feloniously Killed and Assaulted Law Enforcement Officers Killed and Assaulted Program; Analysis of Officers Accidentally Killed...

Copper Reduction and Contact Killing of Bacteria by Iron Surfaces

PubMed Central

Mathews, Salima; Kumar, Ranjeet

2015-01-01

The well-established killing of bacteria by copper surfaces, also called contact killing, is currently believed to be a combined effect of bacterial contact with the copper surface and the dissolution of copper, resulting in lethal bacterial damage. Iron can similarly be released in ionic form from iron surfaces and would thus be expected to also exhibit contact killing, although essentially no contact killing is observed by iron surfaces. However, we show here that the exposure of bacteria to iron surfaces in the presence of copper ions results in efficient contact killing. The process involves reduction of Cu2+ to Cu+ by iron; Cu+ has been shown to be considerably more toxic to cells than Cu2+. The specific Cu+ chelator, bicinchoninic acid, suppresses contact killing by chelating the Cu+ ions. These findings underline the importance of Cu+ ions in the contact killing process and infer that iron-based alloys containing copper could provide novel antimicrobial materials. PMID:26150470

Acute kidney injury associated with concomitant vancomycin and piperacillin/tazobactam administration: a systematic review and meta-analysis.

PubMed

Chen, Xiao-Yu; Xu, Ri-Xiang; Zhou, Xin; Liu, Yang; Hu, Cheng-Yang; Xie, Xue-Feng

2018-05-11

As a tricyclic glycopeptide antibiotic used to treat acute infections, Vancomycin (VAN) is often administered with piperacillin/tazobactam (PT) to treat various infections in clinical practice. However, whether the combination of these two drugs, compared to VAN alone, can cause an increased risk of acute kidney injury (AKI) remains controversial. This study aims to identify the correlation between the development of AKI and the combined use of VAN and PT. We conducted a meta-analysis of eight observational cohort studies (a total of 10727 participants received VAN and PT versus VAN and other β-lactams). PubMed, Chinese Biological Medicine Database (CBM), China National Knowledge Infrastructure (CNKI) Database, Wan Fang Digital Periodicals Database (WFDP), and China Science Citation Database (CSCD) were searched through April 2017 using "vancomycin" and "piperacillin" and "tazobactam" as well as "acute kidney injury" or "acute renal failure" or "AKI" or "ARF" or "nephrotoxicity." Two reviewers extracted the data and assessed the risk of bias. A correlation was found between the development of AKI and concurrent use of VAN and PT compared with concomitant VAN and β-lactams (OR 1.57; 95% CI, 1.13-2.01; I 2  = 76.4%, p < 0.001). Similar findings were obtained in an analysis of studies comparing concurrent VAN and PT use with concurrent VAN and β-lactam (cefepime) use (OR 1.50; 95% CI, 1.07-1.93; I 2  = 80.5%, p < 0.001). Exclusion of fair-quality and low-quality articles did not change the results (OR 1.49; 95% CI, 1.06-1.92; I 2  = 84.1%, p < 0.001). Regarding β-lactam therapy in clinical practice, an elevated risk of AKI due to the combined use of VAN and PT should be considered.

Characterization and modelling of VanT: a novel, membrane-bound, serine racemase from vancomycin-resistant Enterococcus gallinarum BM4174.

PubMed

Arias, C A; Martín-Martinez, M; Blundell, T L; Arthur, M; Courvalin, P; Reynolds, P E

1999-03-01

Sequence determination of a region downstream from the vanXYc gene in Enterococcus gallinarum BM4174 revealed an open reading frame, designated vanT, that encodes a 698-amino-acid polypeptide with an amino-terminal domain containing 10 predicted transmembrane segments. The protein contained a highly conserved pyridoxal phosphate attachment site in the C-terminal domain, typical of alanine racemases. The protein was overexpressed in Escherichia coli, and serine racemase activity was detected in the membrane but not in the cytoplasmic fraction after centrifugation of sonicated cells, whereas alanine racemase activity was located almost exclusively in the cytoplasm. When the protein was overexpressed as a polypeptide lacking the predicted transmembrane domain, serine racemase activity was detected in the cytoplasm. The serine racemase activity was partially (64%) inhibited by D-cycloserine, whereas host alanine racemase activity was almost totally inhibited (97%). Serine racemase activity was also detected in membrane preparations of constitutively vancomycin-resistant E. gallinarum BM4174 but not in BM4175, in which insertional inactivation of the vanC-1 D-Ala:D-Ser ligase gene probably had a polar effect on expression of the vanXYc and vanT genes. Comparative modelling of the deduced C-terminal domain was based on the alignment of VanT with the Air alanine racemase from Bacillus stearothermophilus. The model revealed that almost all critical amino acids in the active site of Air were conserved in VanT, indicating that the C-terminal domain of VanT is likely to adopt a three-dimensional structure similar to that of Air and that the protein could exist as a dimer. These results indicate that the source of D-serine for peptidoglycan synthesis in vancomycin-resistant enterococci expressing the VanC phenotype involves racemization of L- to D-serine by a membrane-bound serine racemase.

Communicating the promise, risks, and ethics of large-scale, open space microbiome and metagenome research.

PubMed

Shamarina, Daria; Stoyantcheva, Iana; Mason, Christopher E; Bibby, Kyle; Elhaik, Eran

2017-10-04

The public commonly associates microorganisms with pathogens. This suspicion of microorganisms is understandable, as historically microorganisms have killed more humans than any other agent while remaining largely unknown until the late seventeenth century with the works of van Leeuwenhoek and Kircher. Despite our improved understanding regarding microorganisms, the general public are apt to think of diseases rather than of the majority of harmless or beneficial species that inhabit our bodies and the built and natural environment. As long as microbiome research was confined to labs, the public's exposure to microbiology was limited. The recent launch of global microbiome surveys, such as the Earth Microbiome Project and MetaSUB (Metagenomics and Metadesign of Subways and Urban Biomes) project, has raised ethical, financial, feasibility, and sustainability concerns as to the public's level of understanding and potential reaction to the findings, which, done improperly, risk negative implications for ongoing and future investigations, but done correctly, can facilitate a new vision of "smart cities." To facilitate improved future research, we describe here the major concerns that our discussions with ethics committees, community leaders, and government officials have raised, and we expound on how to address them. We further discuss ethical considerations of microbiome surveys and provide practical recommendations for public engagement.

The Physics and Materials Science of Superheroes

NASA Astrophysics Data System (ADS)

Kakalios, James

While physicists, engineers and materials scientists don't typically consult comic books when selecting research topics; innovations first introduced in superhero adventures as fiction can sometimes find their way off the comic book page and into reality. As amazing as the Fantastic Four's powers is the fact that their costumes are undamaged when the Human Torch flames on or Mr. Fantastic stretches his elastic body. In shape memory materials, an external force or torque induces a structural change that is reversed upon warming, a feature appreciated by Mr. Fantastic. Spider-Man's wall crawling ability has been ascribed to the same van der Waals attractive force that gecko lizards employ through the millions of microscopic hairs on their toes. Scientists have developed ``gecko tape, consisting of arrays of fibers that provide a strong enough attraction to support a modest weight (if this product ever becomes commercially available, I for one will never wait for the elevator again!). All this, and important topics such as: was it ``the fall or the webbing that killed Gwen Stacy, Spider-Man's girlfriend in the classic Amazing Spider-Man # 121, and the chemical composition of Captain America's shield, will be discussed. Superhero comic books often get their science right more often than one would expect!

Building and design defects observed in the residential sector and the types of damage observed in recent earthquakes in Turkey

NASA Astrophysics Data System (ADS)

Tolga Çöğürcü, M.

2015-01-01

Turkey is situated in a very active earthquake region. In the last century, several earthquakes resulted in thousands of deaths and enormous economic losses. In 1999, the Marmara earthquake had an approximate death toll of more than 20 000, and in 2011, the Van earthquake killed 604 people. In general, Turkish residential buildings have reinforced concrete structural systems. These reinforced concrete structures have several deficiencies, such as low concrete quality, non-seismic steel detailing, and inappropriate structural systems including several architectural irregularities. In this study, the general characteristics of Turkish building stock and the deficiencies observed in structural systems are explained, and illustrative figures are given with reference to Turkish Earthquake Code 2007 (TEC, 2007). The poor concrete quality, lack of lateral or transverse reinforcement in beam-column joints and column confinement zones, high stirrup spacings, under-reinforced columns and over-reinforced beams are the primary causes of failures. Other deficiencies include weak column-stronger beam formations, insufficient seismic joint separations, soft story or weak story irregularities and short columns. Similar construction and design mistakes are also observed in other countries situated on active earthquake belts. Existing buildings still have these undesirable characteristics, so to prepare for future earthquakes, they must be rehabilitated.

Construction and design defects in the residential buildings and observed earthquake damage types in Turkey

NASA Astrophysics Data System (ADS)

Cogurcu, M. T.

2015-04-01

Turkey is situated in a very active earthquake region. In the last century, several earthquakes resulted in thousands of deaths and enormous economic losses. In 1999, the Kocaeli earthquake had an approximate death toll of more than 20 000, and in 2011 the Van earthquake killed 604 people. In general, Turkish residential buildings have reinforced concrete structural systems. These reinforced concrete structures have several deficiencies, such as low concrete quality, non-seismic steel detailing and inappropriate structural systems including several architectural irregularities. In this study, the general characteristics of Turkish building stock and the deficiencies observed in structural systems are explained, and illustrative figures are given with reference to the Turkish Earthquake Code 2007. The poor concrete quality, lack of lateral or transverse reinforcement in beam-column joints and column confinement zones, high stirrup spacings, under-reinforced columns and over-reinforced beams are the primary causes of failures. Other deficiencies include weak-column-stronger-beam formations, insufficient seismic joint separations, soft-story or weak-story irregularities and short columns. Similar construction and design mistakes are also observed in other countries situated on active earthquake belts. Existing buildings still have these undesirable characteristics, and so to prepare for future earthquakes they must be rehabilitated.

Space Van system update

NASA Astrophysics Data System (ADS)

Cormier, Len

1992-07-01

The Space Van is a proposed commercial launch vehicle that is designed to carry 1150 kg to a space-station orbit for a price of $1,900,000 per flight in 1992 dollars. This price includes return on preoperational investment. Recurring costs are expected to be about $840,000 per flight. The Space Van is a fully reusable, assisted-single-stage-to orbit system. The most innovative new feature of the Space Van system is the assist-stage concept. The assist stage uses only airbreathing engines for vertical takeoff and vertical landing in the horizontal attitude and for launching the rocket-powered orbiter stage at mach 0.8 and an altitude of about 12 km. The primary version of the orbiter is designed for cargo-only without a crew. However, a passenger version of the Space Van should be able to carry a crew of two plus six passengers to a space-station orbit. Since the Space Van is nearly single-stage, performance to polar orbit drops off significantly. The cargo version should be capable of carrying 350 kg to a 400-km polar orbit. In the passenger version, the Space Van should be able to carry two crew members - or one crew member plus a passenger.

Critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point using the combination of the Tompa model and the van der Waals equation.

PubMed

Gençaslan, Mustafa; Keskin, Mustafa

2012-02-14

We combine the modified Tompa model with the van der Waals equation to study critical lines for an unequal size of molecules in a binary gas-liquid mixture around the van Laar point. The van Laar point is coined by Meijer and it is the only point at which the mathematical double point curve is stable. It is the intersection of the tricritical point and the double critical end point. We calculate the critical lines as a function of χ(1) and χ(2), the density of type I molecules and the density of type II molecules for various values of the system parameters; hence the global phase diagrams are presented and discussed in the density-density plane. We also investigate the connectivity of critical lines at the van Laar point and its vicinity and discuss these connections according to the Scott and van Konynenburg classifications. It is also found that the critical lines and phase behavior are extremely sensitive to small modifications in the system parameters. © 2012 American Institute of Physics

The Evil Animal: A Terror Management Theory Perspective on the Human Tendency to Kill Animals.

PubMed

Lifshin, Uri; Greenberg, Jeff; Zestcott, Colin A; Sullivan, Daniel

2017-06-01

This research tested whether support for the killing of animals serves a terror management function. In five studies, death primes caused participants to support the killing of animals more than control primes, unless the participants' self-esteem had been elevated (Study 4). This effect was not moderated by gender, preexisting attitudes toward killing animals or animal rights, perceived human-animal similarity, religiosity, political orientation, or by the degree to which the killing was justified. Support for killing animals after subliminal death primes was also associated with an increased sense of power and invulnerability (Study 5). Implications and future directions are discussed.

Bull heading to kill live gas wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oudeman, P.; Avest, D. ter; Grodal, E.O.

1994-12-31

To kill a live closed-in gas well by bull heading down the tubing, the selected pump rate should be high enough to ensure efficient displacement of the gas into the formation (i.e., to avoid the kill fluid bypassing the gas). On the other hand, the pressures that develop during bull heading at high rate must not exceed wellhead pressure rating, tubing or casing burst pressures or the formation breakdown gradient, since this will lead, at best, to a very inefficient kill job. Given these constraints, the optimum kill rate, requited hydraulic horsepower, density and type of kill fluids have tomore » be selected. For this purpose a numerical simulator has been developed, which predicts the sequence of events during bull heading. Pressures and flow rates in the well during the kill job are calculated, taking to account slip between the gas and kill fluid, hydrostatic and friction pressure drop, wellbore gas compression and leak-off to the formation. Comparison with the results of a dedicated field test demonstrates that these parameters can be estimated accurately. Example calculations will be presented to show how the simulator can be used to identify an optimum kill scenario.« less

30-year lidar observations of the stratospheric aerosol layer state over Tomsk (Western Siberia, Russia)

NASA Astrophysics Data System (ADS)

Zuev, Vladimir V.; Burlakov, Vladimir D.; Nevzorov, Aleksei V.; Pravdin, Vladimir L.; Savelieva, Ekaterina S.; Gerasimov, Vladislav V.

2017-02-01

There are only four lidar stations in the world which have almost continuously performed observations of the stratospheric aerosol layer (SAL) state over the last 30 years. The longest time series of the SAL lidar measurements have been accumulated at the Mauna Loa Observatory (Hawaii) since 1973, the NASA Langley Research Center (Hampton, Virginia) since 1974, and Garmisch-Partenkirchen (Germany) since 1976. The fourth lidar station we present started to perform routine observations of the SAL parameters in Tomsk (56.48° N, 85.05° E, Western Siberia, Russia) in 1986. In this paper, we mainly focus on and discuss the stratospheric background period from 2000 to 2005 and the causes of the SAL perturbations over Tomsk in the 2006-2015 period. During the last decade, volcanic aerosol plumes from tropical Mt. Manam, Soufrière Hills, Rabaul, Merapi, Nabro, and Kelut and extratropical (northern) Mt. Okmok, Kasatochi, Redoubt, Sarychev Peak, Eyjafjallajökull, and Grímsvötn were detected in the stratosphere over Tomsk. When it was possible, we used the NOAA HYSPLIT trajectory model to assign aerosol layers observed over Tomsk to the corresponding volcanic eruptions. The trajectory analysis highlighted some surprising results. For example, in the cases of the Okmok, Kasatochi, and Eyjafjallajökull eruptions, the HYSPLIT air mass backward trajectories, started from altitudes of aerosol layers detected over Tomsk with a lidar, passed over these volcanoes on their eruption days at altitudes higher than the maximum plume altitudes given by the Smithsonian Institution Global Volcanism Program. An explanation of these facts is suggested. The role of both tropical and northern volcanic eruptions in volcanogenic aerosol loading of the midlatitude stratosphere is also discussed. In addition to volcanoes, we considered other possible causes of the SAL perturbations over Tomsk, i.e., the polar stratospheric cloud (PSC) events and smoke plumes from strong forest fires. At least two PSC events were detected in 1995 and 2007. We also make an assumption that the Kelut volcanic eruption (Indonesia, February 2014) could be the cause of the SAL perturbations over Tomsk during the first quarter of 2015.

Photogrammetric Retrieval of Etna's Plume Height from SEVIRI and MODIS

NASA Astrophysics Data System (ADS)

Zaksek, K.; Ganci, G.; Hort, M. K.

2013-12-01

Even remote volcanoes can impact the modern society due to volcanic ash dispersion in the atmosphere. A lot of research is currently dedicated to minimizing the impact of volcanic ash on air traffic. But the ash transport in the atmosphere and its deposition on land and in the oceans may also significantly influence the climate through modifications of atmospheric CO2. The emphasis of this contribution is the retrieval of volcanic ash plume height. This is important information for air traffic, to predict ash transport and to estimate the mass flux of the ejected material. The best way to monitor volcanic ash cloud top height (ACTH) on the global level is using satellite remote sensing. The most commonly used method for satellite ACTH compares brightness temperature of the cloud with the atmospheric temperature profile. Because of well-known uncertainties of this method we propose photogrammetric methods based on the parallax between data retrieved from geostationary (SEVIRI, HRV band; 1000 m spatial resolution) and polar orbiting satellites (MODIS, band 1; 250 m spatial resolution). The procedure works well if the data from both satellites are retrieved nearly simultaneously butMODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection in the atmosphere we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. ACTH is then estimated by intersection of corresponding lines-of-view from MODIS and interpolated SEVIRI data. The proposed method has already been tested for the case of the Eyjafjallajökull eruption in April 2010. This case study had almost perfect conditions as the plume was vast and stretching over a homogeneous background - ocean. Here we show results of ACTH estimation during lava fountaining activity of Mount Etna in years 2011-2013. This activity resulted in volcanic ash plumes that are much smaller than the plume observed at Eyjafjallajökull eruption. Challenges and problems occurring while applying the photogrammetric method to small and medium sized plumes will be discussed and solutions to those challenges will be shown.

Modelling of Subglacial Volcanic and Geothermal Activity, during the 2014-15 Bárdarbunga-Holuhraun Eruption and Caldera Collapse

NASA Astrophysics Data System (ADS)

Reynolds, H. I.; Gudmundsson, M. T.; Hognadottir, T.

2015-12-01

Seismic unrest was observed within the subglacial caldera of Bárdarbunga on 16 August 2014, followed by seismicity tracing the path of a lateral dyke extending underneath the Vatnajökull glacier out to 45 km to the north east of the volcano. A short subaerial fissure eruption occurred at the site of the Holuhraun lavas, just north of the glacier edge on 29 August, before recommencing in earnest on 31 August with a large effusive eruption and accompanying slow caldera collapse, which lasted for approximately 6 months. The glacier surface around Bárdarbunga was monitored using aerial altimeter profiling. Several shallow depressions, known as ice cauldrons, formed around the caldera rim and on Dyngjujökull glacier above the dyke propagation path. The cauldrons range in volume from approximately 0.0003 km3 to 0.02 km3. Two types of melting were observed: high initial heat flux over a period of days which gradually disappears; and slower but more sustained melting rates. We present time series data of the development and evolution of these cauldrons, with estimates of the heat flux magnitudes involved.The nature of the heat source required to generate these cauldrons is not obvious. Two scenarios are explored: 1) small subglacial eruptions; or 2) increased geothermal activity induced by the dyke intrusion. We investigate these scenarios using numerical modelling, considering the surface heat flux produced, and timescales and spatial extent of associated surface anomalies. It is found that a magmatic intrusion into rocks where the groundwater is near the boiling point curve can cause rapid increase in geothermal activity, but even a shallow intrusion into a cold groundwater reservoir will have a muted thermal response. Thus, our results indicate that minor subglacial eruptions are the most plausible explanation for the observed rapid melting far from known geothermal areas. These results have implications for the interpretation of thermal signals observed at ice-covered volcanoes, highlighting the importance of reservoir/bedrock thermal state prior to intrusion.

Preservation potential of subtle glacial landforms based on detailed mapping of recently exposed proglacial areas: application of unmanned aerial vehicle (UAV) and structure-from-motion (SfM)

NASA Astrophysics Data System (ADS)

Ewertowski, Marek; Evans, David; Roberts, David; Tomczyk, Aleksandra; Ewertowski, Wojciech

2016-04-01

Ongoing glacier retreat results in the continuous exposure of proglacial areas. Such areas contain invaluable information about glacial process-form relationships manifest in specific landform assemblages. However, preservation potential of freshly exposed glacial landforms is very low, as proglacial terrains are one of the most dynamic parts of the landscape. Therefore, rapid mapping and geomorphological characterisation of such areas is important from a glaciological and geomorphological point of view for proper understanding and reconstruction of glacier-landform dynamics and chronology of glacial events. Annual patterns of recession and relatively small areas exposed every year, mean that the performing of regular aerial or satellite survey is expensive and therefore impractical. Recent advances in technology enables the development of low-cost alternatives for traditional aerial surveys. Small unmanned aerial vehicles (UAV) can be used to acquire high-resolution (several cm) low-altitude photographs. The UAV-based photographs can be subsequently processed through the structure-from-motion process to generate detailed orthophotomaps and digital elevation models. In this study we present case studies from the forelands of various glaciers on Iceland and Svalbard representing different types of proglacial landscapes: Fláajökull (annual push moraines); Hofellsjökul (bedrock bedforms and push moraines); Fjallsjökull (marginal drainage network); Rieperbreen (crevasse squeeze ridges and longitudinal debris stripes); Ayerbreen (transverse debris ridges); Foxfonna (longitudinal debris stripes);Hørbyebreen (geometric ridge network); Nordenskiöldbreen (fluted till surface); Ebbabreen (controlled moraine complex). UAV campaigns were conducted using a low-cost quadcopter platform. Resultant orthophotos and DEMs enabled mapping and assessment of recent glacial landscape development in different types of glacial landsystems. Results of our study indicate that preservation potential of geometric ridge networks and debris stripes produced by polythermal glaciers on Svalbard is very low (< 5 years), whereas subtle landforms indicative for temperate conditions: annual push moraines (Iceland)and flutings (Iceland and Svalbard) - can survive decades without being seriously modified.

Importance of nanoparticles and colloids from volcanic ash for riverine transport of trace elements to the ocean: evidence from glacial-fed rivers after the 2010 eruption of Eyjafjallajökull Volcano, Iceland.

PubMed

Tepe, Nathalie; Bau, Michael

2014-08-01

Volcanic ashes are often referenced as examples for natural nanoparticles, yet the particle size distribution <1000 nm is only rarely documented. We here report results of a geochemical study of glacial-fed rivers, glacial surface runoff, glacial base flow, and pure glacial meltwater from southern Iceland, that had been sampled 25 days after the explosive eruptions at Eyjafjallajökull in 2010. In addition to the dissolved concentrations of rare earth elements (REE), Zr, Hf, Nb, and Th in the 450 nm-filtered waters, we also studied the respective filter residues (river particulates >450 nm) and volcanic ash. In spite of the low solubilities and high particle-reactivities of the elements studied, most water samples show high dissolved concentrations, such as up to 971 ng/kg of Ce and 501 ng/kg of Zr. Except for the pure glacial meltwater and glacial base flow, all waters display the same shale-normalized REE patterns with pronounced light and heavy REE depletion and positive Eu anomalies. While such patterns are unusual for river waters, they are similar to those of the respective river particulates and the volcanic ash, though at different concentration levels. The distribution of dissolved Zr, Hf, Nb, and Th in the waters also matches that of filter residues and ash. This strongly suggests that in all 450 nm-filtered river waters, the elements studied are associated with solid ash particles smaller than 450 nm. This reveals that volcanic ash-derived nanoparticles and colloids are present in these glacial-fed rivers and that such ultrafine particles control the trace element distribution in the surface runoff. Subsequent to explosive volcanic eruptions, these waters provide terrigenous input from landmasses to estuaries, that is characterized by a unique trace element signature and that subsequent to modification by estuarine processes delivers a pulse of nutrients to coastal seawater in regions not affected by plume fall-out. Copyright © 2014 Elsevier B.V. All rights reserved.

Eyjafjallajökull2010 - The activity of the eruption plume during the first 2 weeks

NASA Astrophysics Data System (ADS)

Sigurősson, Árni; Pálmason, Bolli; Hlíőar Jensen, Esther; Petersen, Gudrun Nina; Björnsson, Halldór; Şorsteinsson, Hróbjartur; Arason, Şórőur

2010-05-01

On 14 April 2010 an eruption started in Eyjafjallajökull, in southern Iceland. This was an explosive eruption in the caldera, beneath the glacier. During the first two weeks the eruption went through two phases, an explosive phase with much tephra and ash production and a calmer phase with less productivity and some lava production. During the explosive phase 14-17 April, the plume altititude was about 5-7 km but occasionally increased up to 8 km height, there was lightning activity in the plume and the material produced was mainly ash and tephra. It is estimated that the production was peaked at about 750 tons/s. The local ash fall on 17 April was the worst by far for the local community to the south of the volcano as about a 1 km thick ash cloud flowed almost continuously from the volcano and over the region. During this phase the upper level winds over Iceland were strong, northwesterly 40-50 m/s, and the emitted ash was advected southeastward toward northwestern Europe. This caused major disruption in air traffic. During the second phase 18-29 April there was a reduced net output form the volcano, lava production was estimated as 10-30 tons/s and tephra and ash production of less than 10 tons/s. The height of the plume was estimated as 3-5 km. Local ash fall predictions were made for the areas within a 500 km radius from the eruption site and prediction maps published on the website of the Icelandic Met Office. Information on local ash fall were collected from synoptic weather stations but also from the general public and the media. An internet web registration form was made public and advertised. In 6 days 95 reports of ash fall were made. This information together with other ground observations and remote sense observations are important for validations of ash fall prediction, near field and far field, as well as ensuring that the impact of the volcanic eruption is well understood, in a geological, geophysical and biological sense but also the societal impact on the communities affected.

Geomicrobiology of basal ice in a temperate glacier: implications for primary microbial production and export, elemental cycling and soil formation

NASA Astrophysics Data System (ADS)

Toubes-Rodrigo, Mario; Potgieter-Vermaak, Sanja; Sen, Robin; Elliott, David R.; Cook, Simon J.

2017-04-01

Basal ice is a significant sub-glacial component of glaciers and ice sheets that arises from ice-bedrock/substrate interaction. As a result, basal ice of a glacier retains a distinctive physical and chemical signature characterised by a high sediment- and low bubble-content and selective ionic enrichment. Previous research concluded that sediment entrapped in the basal ice matrix originates from the bedrock/substrate, and harbours an active microbial community. However, the nature and significance of the microbial community inhabiting basal ice facies remains poorly characterised. This paper reports on an integrated chemical, mineralogical, and microbial community analysis of basal ice in the subglacial environment at Svínafellsjökull, in south-east Iceland. Basal ice sediment supported 10E7 cells g^-1 and, based on glacier velocity and sediment flux, an estimated 10E17 cells a^-1 are exported to the glacier foreland. Furthermore, 16S rRNA gene analysis highlighted a glacier basal ice bacterial community dominated by Proteobacteria, Acidobacteria, Actinobacteria, and Chloroflexi. Sequences ascribed to chemolithotrophic-related species (Thiobacillus, Syderoxidans) were highly abundant. Minerological analyses of basal ice sediment confirmed dominant silicates and iron-containing minerals that represent susceptible substrates open to oxidation by the aforementioned chemolithotrophs. Previous studies have suggested that basal ice could constitute a good analogue for astrobiology. Svínafellsjökull and Mars geology are similar - volcanically derived rocks with a high abundance of silicates and iron-rich minerals, reinforcing this idea. Understanding where the limits of life in extreme environments, such as debris-rich basal ice, could help to unravel how life on other planets could succeed, and could help to identify which markers to use in order to find it. In dark and isolated basal ice niches, the dominating chemolithotrophic bacterial community are likely to act as primary producers, fixing carbon while weathering minerals and thus providing a plausible mechanism to explain how a basal ice microbial ecosystem can be sustained.

9 CFR 113.208 - Avian Encephalomyelitis Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Avian Encephalomyelitis Vaccine... STANDARD REQUIREMENTS Killed Virus Vaccines § 113.208 Avian Encephalomyelitis Vaccine, Killed Virus. Avian Encephalomyelitis Vaccine (Killed Virus) shall be prepared from virus-bearing tissues or fluids obtained from...

9 CFR 113.208 - Avian Encephalomyelitis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Avian Encephalomyelitis Vaccine... STANDARD REQUIREMENTS Killed Virus Vaccines § 113.208 Avian Encephalomyelitis Vaccine, Killed Virus. Avian Encephalomyelitis Vaccine (Killed Virus) shall be prepared from virus-bearing tissues or fluids obtained from...

Nanotechnology-Enabled Optical Molecular Imaging of Breast Cancer

DTIC Science & Technology

2013-09-01

Jacobus J M van Der Hoeven, Elsken van Der Wall, Petra van Der Groep, Paul J van Diest, Emile F I Comans, Urvi Joshi, et al. 2002. “Biologic...Leigh G Seamon, William B Farrar, and Edward W Martin . 2008. “Novel perioperative imaging with 18F-FDG PET/CT and intraoperative 18F-FDG detection...www.springerlink.com/content/n752170246r84660/. Hall, Nathan C, Stephen P Povoski, Douglas A Murrey, Michael V Knopp, and Edward W Martin . 2007. “Combined

Submaximal Exercise Testing Treadmill and Floor Walking.

DTIC Science & Technology

1978-05-01

Amputations," Archives of Physical Medicine and Rehabilitation, 56:67-71, 1975. 36. van der Walt, W. H., and Wyndham, C. H,, "An Equation for...C. H., van Renaburg, A. J., Rogr, G. G., Greyson, J. S.. and van der Walt, V. H., "Walk or Jog for Health: I, The Energy Cost of Walking or Running at...G., Greyson, J. S., and van der Walt, V. H., "Walk or Jog for Health: II, Iatimating the Maximi Aerobic Capacity for Exercise,* South &frIca Kedical

A Representational Approach to Knowledge and Multiple Skill Levels for Broad Classes of Computer Generated Forces

DTIC Science & Technology

1997-12-01

that I’ll turn my attention to that computer game we’ve talked so much about... Dave Van Veldhuizen and Scott Brown (soon-to-be Drs. Van Veldhuizen and...Industry Training Systems Conference. 1988. 37. Van Veldhuizen , D. A. and L. J Hutson. "A Design Methodology for Domain Inde- pendent Computer...proposed by Van Veld- huizen and Hutson (37), extends the general architecture to support both a domain- independent approach to implementing CGFs and

REMOTE LAND MINE(FIELD) DETECTION. An Overview of Techniques (DETECTIE VAN LANDMIJNEN EN MIJNENVELDEN OP AFSTAND. Een Overzicht van de technieken),

DTIC Science & Technology

1994-09-01

titel DETECTIE VAN LANDMIJNEN EN MIJNENVELDEN OP AFSTAND, een overzicht van de technieken auteur (s) Drs. J.S. Groot, Ir. Y.H.L. Janssen datum september...functions based on set theory . The fundamental theory is developed in the sixties. This theory was applicable to binary images (black-and-white images...held at TNO-FEL. Various subjects related to fusion techniques: Dempster Shafer theory , Bayesian inference, Kalman filtering, fuzzy logic. [A15], [B4

Beta-catenin: A Potential Survival Marker of Breast Cancer Stem Cells

DTIC Science & Technology

2006-09-01

T. C., Alexander, C. M., Georges-Labouesse, E., Van der Neut , R., Kreidberg, J. A., Jones, C. J., Sonnenberg, A. and Streuli, C. H. (2001...de Lau, W., Oving, I., Hurlstone, A., van der Horn, K., Batlle, E., Coudreuse, D., Haramis, A. P., Tjon-Pon-Fong, M., Moerer, P., van den Born, M...Scherer, D. C., Willert, K., Hintz, L., Nusse, R. & Weissman, I. L. (2003) Nature 423, 409-14. 36. van de Wetering, M., Sancho, E., Verweij, C

DoD Electronic Data Interchange (EDI) Convention: ASC X12 Transaction Set 836 Contract Award (Version 003010)

DTIC Science & Technology

1993-01-01

upon designation of DoD Activity Address Code (DoDAAC) or other code coordinated with the value-added network (VAN). Mandatory ISA06 106 Interc.ange...coordinated with the value-added network (VAN). Non-DoD activities use identification code qualified by ISA05 and coordinated with the VAN. Mandatory...designation of DoD Activity Address Code (DoDAAC) or other code coordinated with the value-added network (VAN). Mandatory ISA08 107 Interchange Receiver

Definitie Rapport Taktisch LAN Demonstratie (Definition Report Tactical LAN Demonstration)

DTIC Science & Technology

1990-06-01

am deze sneiheid te halen . Hierover kan eon uitspraak warden gedaan, enerzijds na de ontwikkeling van het S-4 interface en anderzijds na berokeningen...90-A02 *2ma~D. Definitie rapport taktisch LAN Niels Ult deze urgave reai erorden verrnengvldigd er of openbaar genakt door MiddeI van druk. folokopre...microfrilm Of OP wetke arroere 00lze 000 00k. zonoe, O~u S vdorafgaanoe loestermeng van TNOHet ter inzage gen van het TNO-rapport Ing. R. J . C.14

Testbed Environment for Distributed Observation (testbed omgeving voor gedistribueerde waarneming)

DTIC Science & Technology

2006-05-01

het IP-adres en portnumnmer van de MID halen . Ook de naamn van de XML-file om de NID te beschrijven staat hierin vermeld (in dit geval ’CSD.xmId’) in...DeviceML beschrijving van de NID op te halen . Dit wordt gedaan door een TCP/IP verbinding op te zetten tussen de LUS en de NID (via de DeviceML port...vernisenigvuidigd! enlof openbaar gensaaki door middel van druk, fotokopie, microftinm of op welke andere wijze dan ook, zonder voorafgaande schrifielijke

Spacetimes with Killing tensors. [for Einstein-Maxwell fields with certain spinor indices

NASA Technical Reports Server (NTRS)

Hughston, L. P.; Sommers, P.

1973-01-01

The characteristics of the Killing equation and the Killing tensor are discussed. A conformal Killing tensor is of interest inasmuch as it gives rise to a quadratic first integral for null geodesic orbits. The Einstein-Maxwell equations are considered together with the Bianchi identity and the conformal Killing tensor. Two examples for the application of the considered relations are presented, giving attention to the charged Kerr solution and the charged C-metric.

Structural and Functional Adaptation of Vancomycin Resistance VanT Serine Racemases

PubMed Central

Meziane-Cherif, Djalal; Stogios, Peter J.; Evdokimova, Elena; Egorova, Olga

2015-01-01

ABSTRACT Vancomycin resistance in Gram-positive bacteria results from the replacement of the d-alanyl–d-alanine target of peptidoglycan precursors with d-alanyl–d-lactate or d-alanyl–d-serine (d-Ala-d-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of d-Ala-d-Ser-terminating precursors by converting l-Ser to d-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in l-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanTG from VanG-type resistant Enterococcus faecalis BM4518 was determined. The structure showed significant similarity to type III pyridoxal 5′-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanTG and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn696 which are responsible for the l-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanTG against l-Ser versus l-Ala implied that this enzyme relies on its membrane-bound domain for l-Ser transport to increase the overall rate of d-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria. PMID:26265719

Structural and functional adaptation of vancomycin resistance VanT serine racemases

DOE PAGES

Meziane-Cherif, Djalal; Stogios, Peter J.; Evdokimova, Elena; ...

2015-08-11

Vancomycin resistance in Gram-positive bacteria results from the replacement of the D-alanyl–D-alanine target of peptidoglycan precursors with D-alanyl–D-lactate or D-alanyl–D-serine (D-Ala-D-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of D-Ala-D-Ser-terminating precursors by converting L-Ser to D-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in L-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanT G from VanG-type resistant Enterococcus faecalis BM4518more » was determined. The structure showed significant similarity to type III pyridoxal 5'-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanT G and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn 696 which are responsible for theL-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanT G against L-Ser versus L-Ala implied that this enzyme relies on its membrane-bound domain for L-Ser transport to increase the overall rate of D-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria.« less

Incidence of Male-Killing Rickettsia spp. (α-Proteobacteria) in the Ten-Spot Ladybird Beetle Adalia decempunctata L. (Coleoptera: Coccinellidae)

PubMed Central

von der Schulenburg, J. Hinrich Graf; Habig, Michael; Sloggett, John J.; Webberley, K. Mary; Bertrand, Dominique; Hurst, Gregory D. D.; Majerus, Michael E. N.

2001-01-01

The diversity of endosymbiotic bacteria that kill male host offspring during embryogenesis and their frequencies in certain groups of host taxa suggest that the evolution of male killing and the subsequent spread of male-killing symbionts are primarily determined by host life history characteristics. We studied the 10-spot ladybird beetle, Adalia decempunctata L. (Coleoptera: Coccinellidae), in which male killing has not been recorded previously, to test this hypothesis, and we also assessed the evolution of the male killer identified by DNA sequence analysis. Our results show that A. decempunctata harbors male-killing Rickettsia (α-proteobacteria). Male-killing bacteria belonging to the genus Rickettsia have previously been reported only for the congeneric two-spot ladybird beetle, Adalia bipunctata L. Phylogenetic analysis of Rickettsia DNA sequences isolated from different populations of the two host species revealed a single origin of male killing in the genus Rickettsia. The data also indicated possible horizontal transfer of symbionts between host species. In addition, A. bipunctata is known to bear at least four different male-killing symbionts in its geographic range two of which coexist in the two locations from which A. decempunctata specimens were obtained for the present study. Since only a single male-killing taxon was found in A. decempunctata, we assume that the two closely related ladybird beetle species must differ in the number and/or geographic distribution of male killers. We discuss the importance of these findings to our understanding of the evolution and dynamics of symbiotic associations between male-killing bacteria and their insect hosts. PMID:11133455

Comparisons of boll weevil (Coleoptera: Curculionidae) pheromone traps with and without kill strips.

PubMed

Suh, C P C; Armstrong, J S; Spurgeon, D W; Duke, S

2009-02-01

Boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), eradication programs typically equip pheromone traps with an insecticide-impregnated kill strip. These strips are intended to kill captured insects, thereby simplifying trap servicing and reducing the loss of weevils from predation and escape. However, the effectiveness of kill strips has not been extensively evaluated. We examined the influences of kill strips on weevil captures, trap servicing, and the incidences of weevil predation and trap obstruction (e.g., by spider webs). Evaluations were conducted weekly during three different production periods (pre- to early-, late-, and postseason) of cotton, Gossypium hirsutum L., to represent different environmental conditions and weevil population levels. Within each period, mean weekly captures of weevils in traps with and without kill strips were statistically similar. On average, traps with kill strips took 9 s longer to service than traps without kill strips, but statistical differences were only detected during the late-season period. Overall, the mean weekly proportion of traps with evidence of weevil predation or trap obstruction was significantly lower for traps with kill strips (0.25) than for traps without kill strips (0.37). However, this reduction in the frequency of weevil predation or trap obstruction was too small to produce a corresponding increase in the numbers of weevils captured. In light of these findings, the use of kill strips is likely unnecessary in eradication programs, but may be a consideration in situations when the numbers of deployed traps are reduced and chronic problems with weevil predation or trap obstruction exist.

Individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain Lactobacillus johnsonii NCC933 and vaginal strain Lactobacillus gasseri KS120.1 against enteric, uropathogenic and vaginosis-associated pathogens.

PubMed

Atassi, Fabrice; Servin, Alain L

2010-03-01

The mechanism underlying the killing activity of Lactobacillus strains against bacterial pathogens appears to be multifactorial. Here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. In co-culture, the human intestinal strain Lactobacillus johnsonii NCC933 and human vaginal strain Lactobacillus gasseri KS120.1 strains killed enteric Salmonella enterica serovar Typhimurium SL1344, vaginal Gardnerella vaginalis DSM 4944 and urinary tract Escherichia coli CFT073 pathogens. The cell-free culture supernatants (CFCSs) produced the same reduction in SL1344, DSM 4944 and CFT073 viability, whereas isolated bacteria had no effect. The killing activity of CFCSs was heat-stable. In the presence of Dulbecco's modified Eagle's minimum essential medium inhibiting the lactic acid-dependent killing activity, CFCSs were less effective at killing of the pathogens. Catalase-treated CFCSs displayed a strong decreased activity. Tested alone, hydrogen peroxide triggered a concentration-dependent killing activity against all three pathogens. Lactic acid alone developed a killing activity only at concentrations higher than that present in CFCSs. In the presence of lactic acid at a concentration present in Lactobacillus CFCSs, hydrogen peroxide displayed enhanced killing activity. Collectively, these results demonstrate that for hydrogen peroxide-producing Lactobacillus strains, the main metabolites of Lactobacillus, lactic acid and hydrogen peroxide, act co-operatively to kill enteric, vaginosis-associated and uropathogenic pathogens.

Stirling Powered Van Progam overview

NASA Technical Reports Server (NTRS)

Shaltens, R. K.

1986-01-01

The Stirling Powered Van Program (SPVP) is a multiyear, multiphase program to evaluate the automotive Stirling engine (ASE) in Air Force vans under realistic conditions. The objective of the SPVP is to transfer to manufacturer and end user(s) (i.e., on the path to commercialization) the second-generation Mod 2 ASE upon completion of the Automotive Stirling Engine Program in 1987. In order to meet this objective, the SPVP must establish Stirling performance, integrity, reliability, durability and maintainability. The ASE program background leading to the van program is reviewed and plans for evaluating the kinematic Stirling engine in Air Force vans examined. Also discussed are the NASA technology transfers to industry that have been accomplished and those which are currently being developed.

Ecological studies of the timber wolf in Northeastern Minnesota.

Treesearch

L. David Mech; L.D. Jr. Frenzel

1971-01-01

Aerial observations and radio tracking showed that wolves had ranges of 43 to 1,000 square miles. Kill rate during usual winters was one deer per wolf per 18 days, but harsher winters allowed increased kill. Wolf-killed deer generally were older and had more abnormalities than hunter-killed deer.

Planning a dynamic kill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abel, L.W.

1996-05-01

This article discusses the methodology, design philosophy, and guidelines for planning a dynamic-kill operation for a wild well. The topics covered are two methods of computer analysis for designing dynamic-kill requirements, the design process, determining the pumping spread, and the pitfalls that a designer faces in planning a dynamic kill.

75 FR 30299 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0355] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from regulations. SUMMARY: The Commander...

75 FR 62469 - Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0907] Drawbridge Operation Regulations; Newtown Creek, Dutch Kills, English Kills, and Their Tributaries, NY, Maintenance AGENCY: Coast Guard, DHS. ACTION: Notice of temporary deviation from regulations. SUMMARY: The Commander...

9 CFR 113.204 - Mink Enteritis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Mink Enteritis Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.204 Mink Enteritis Vaccine, Killed Virus. Mink Enteritis Vaccine... prior to challenge. If unfavorable reactions attributable to the vaccine occur, the serial is...

9 CFR 113.201 - Canine Distemper Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Canine Distemper Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.201 Canine Distemper Vaccine, Killed Virus. Canine Distemper Vaccine... been established as pure, safe, and immunogenic shall be used for vaccine production. All serials of...

9 CFR 113.205 - Newcastle Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Newcastle Disease Vaccine, Killed Virus. 113.205 Section 113.205 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.205 Newcastle Disease Vaccine, Killed Virus. Newcastle Disease Vaccine...

9 CFR 113.205 - Newcastle Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Newcastle Disease Vaccine, Killed Virus. 113.205 Section 113.205 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.205 Newcastle Disease Vaccine, Killed Virus. Newcastle Disease Vaccine...

9 CFR 113.204 - Mink Enteritis Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Mink Enteritis Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.204 Mink Enteritis Vaccine, Killed Virus. Mink Enteritis Vaccine... prior to challenge. If unfavorable reactions attributable to the vaccine occur, the serial is...

9 CFR 113.201 - Canine Distemper Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Canine Distemper Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.201 Canine Distemper Vaccine, Killed Virus. Canine Distemper Vaccine... been established as pure, safe, and immunogenic shall be used for vaccine production. All serials of...

9 CFR 113.200 - General requirements for killed virus vaccines.

Code of Federal Regulations, 2014 CFR

2014-01-01

... vaccines. 113.200 Section 113.200 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.200 General requirements for killed virus vaccines. When prescribed in an applicable Standard Requirement or in the filed Outline of Production, a killed virus vaccine...

9 CFR 113.200 - General requirements for killed virus vaccines.

Code of Federal Regulations, 2013 CFR

2013-01-01

... vaccines. 113.200 Section 113.200 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.200 General requirements for killed virus vaccines. When prescribed in an applicable Standard Requirement or in the filed Outline of Production, a killed virus vaccine...

9 CFR 113.212 - Bursal Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Bursal Disease Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.212 Bursal Disease Vaccine, Killed Virus. Bursal Disease Vaccine... for vaccine production. All serials shall be prepared from the first through the fifth passage from...

9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... Master Seed which has been established as pure, safe, and immunogenic shall be used for vaccine...

9 CFR 113.212 - Bursal Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bursal Disease Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.212 Bursal Disease Vaccine, Killed Virus. Bursal Disease Vaccine... for vaccine production. All serials shall be prepared from the first through the fifth passage from...

9 CFR 113.201 - Canine Distemper Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Canine Distemper Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.201 Canine Distemper Vaccine, Killed Virus. Canine Distemper Vaccine... been established as pure, safe, and immunogenic shall be used for vaccine production. All serials of...

9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... Master Seed which has been established as pure, safe, and immunogenic shall be used for vaccine...

9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... Master Seed which has been established as pure, safe, and immunogenic shall be used for vaccine...

9 CFR 113.212 - Bursal Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Bursal Disease Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.212 Bursal Disease Vaccine, Killed Virus. Bursal Disease Vaccine... for vaccine production. All serials shall be prepared from the first through the fifth passage from...

9 CFR 113.201 - Canine Distemper Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Canine Distemper Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.201 Canine Distemper Vaccine, Killed Virus. Canine Distemper Vaccine... been established as pure, safe, and immunogenic shall be used for vaccine production. All serials of...

9 CFR 113.204 - Mink Enteritis Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Mink Enteritis Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.204 Mink Enteritis Vaccine, Killed Virus. Mink Enteritis Vaccine... prior to challenge. If unfavorable reactions attributable to the vaccine occur, the serial is...

9 CFR 113.205 - Newcastle Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Newcastle Disease Vaccine, Killed Virus. 113.205 Section 113.205 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.205 Newcastle Disease Vaccine, Killed Virus. Newcastle Disease Vaccine...

9 CFR 113.204 - Mink Enteritis Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Mink Enteritis Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.204 Mink Enteritis Vaccine, Killed Virus. Mink Enteritis Vaccine... prior to challenge. If unfavorable reactions attributable to the vaccine occur, the serial is...

9 CFR 113.205 - Newcastle Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Newcastle Disease Vaccine, Killed Virus. 113.205 Section 113.205 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.205 Newcastle Disease Vaccine, Killed Virus. Newcastle Disease Vaccine...

9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... Master Seed which has been established as pure, safe, and immunogenic shall be used for vaccine...

9 CFR 113.200 - General requirements for killed virus vaccines.

Code of Federal Regulations, 2011 CFR

2011-01-01

... vaccines. 113.200 Section 113.200 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE... REQUIREMENTS Killed Virus Vaccines § 113.200 General requirements for killed virus vaccines. When prescribed in an applicable Standard Requirement or in the filed Outline of Production, a killed virus vaccine...

9 CFR 113.214 - Parvovirus Vaccine, Killed Virus (Canine).

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Parvovirus Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.214 Parvovirus Vaccine, Killed Virus (Canine). Parvovirus Vaccine... Master Seed which has been established as pure, safe, and immunogenic shall be used for vaccine...

9 CFR 113.212 - Bursal Disease Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Bursal Disease Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.212 Bursal Disease Vaccine, Killed Virus. Bursal Disease Vaccine... for vaccine production. All serials shall be prepared from the first through the fifth passage from...