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Sample records for tephra fall deposits

  1. The Disruption of Tephra Fall Deposits by Basaltic Lava Flows

    Science.gov (United States)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2010-12-01

    Complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents of the Roza Member in the Columbia River Basalt Province, (CRBP), USA, illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter tephra fall deposits. Thin pahoehoe lobes and sheet lobes occur intercalated with tephra deposits and provide evidence for synchronous effusive and explosive activity. Tephra that accumulated on the tops of inflating pahoehoe flows became disrupted by tumuli, which dissected the overlying sheet into a series of mounds. During inflation of subjacent tumuli tephra percolated down into the clefts and rubble at the top of the lava, and in some cases came into contact with lava hot enough to thermally alter it. Lava breakouts from the tumuli intruded up through the overlying tephra deposit and fed pahoehoe flows that spread across the surface of the aggrading tephra fall deposit. Non-welded scoria fall deposits were compacted and welded to a depth of ~50 cm underneath thick sheet lobes. These processes, deduced from the field relationships, have resulted in considerable stratigraphic complexity in proximal regions. We also demonstrate that, when the advance of lava and the fallout of tephra are synchronous, the contacts of some tephra sheets can be diachronous across their extent. The net effect is to reduce the usefulness of pyroclastic deposits in reconstructing eruption dynamics.

  2. Disruption of tephra fall deposits caused by lava flows during basaltic eruptions

    Science.gov (United States)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2015-10-01

    Observations in the USA, Iceland and Tenerife, Canary Islands reveal how processes occurring during basaltic eruptions can result in complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents. Observations illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter sheet-form fall deposits. Complexity arises through synchronous and alternating effusive and explosive activity that results in intercalated lavas and tephra deposits. Tephra deposits can become disrupted into mounds and ridges by lateral and vertical displacement caused by movement (including inflation) of underlying pāhoehoe lavas and clastogenic lavas. Mounds of tephra can be rafted away over distances of 100 s to 1,000 s m from proximal pyroclastic constructs on top of lava flows. Draping of irregular topography by fall deposits and subsequent partial burial of topographic depressions by later lavas can result in apparent complexity of tephra layers. These processes, deduced from field relationships, have resulted in considerable stratigraphic complexity in the studied proximal regions where fallout was synchronous or alternated with inflation of subjacent lava sheets. These mechanisms may lead to diachronous contact relationships between fall deposits and lava flows. Such complexities may remain cryptic due to textural and geochemical quasi-homogeneity within sequences of interbedded basaltic fall deposits and lavas. The net effect of these processes may be to reduce the usefulness of data collected from proximal fall deposits for reconstructing basaltic eruption dynamics.

  3. Holocene tephra-fall deposits of southern and austral Andes volcanic zones (33-54oS): eruption recurrence

    International Nuclear Information System (INIS)

    Naranjo, J.A.; Polanco, E.; Lara, L; Moreno, H; Stern, C.R

    2001-01-01

    Radiometric 14 C dating is a very useful tool to study the chronostratigraphy of pyroclastic deposits. In addition, 14 C ages are essential parameters for the estimation of the recurrence time of the explosive volcanic activity. The origin, distribution and relative age of mappable Holocene tephra-fall deposits of the Southern Andes Volcanic Zone (SVZ) and Austral Andes Volcanic Zone (AVZ) from 33 o S-54 o S, were studied and their recurrence period is analysed (au)

  4. Character, mass, distribution, and origin of tephra-fall deposits of the 1989-1990 eruption of redoubt volcano, south-central Alaska

    Science.gov (United States)

    Scott, W.E.; McGimsey, R.G.

    1994-01-01

    The 1989-1990 eruption of Redoubt Volcano spawned about 20 areally significant tephra-fall deposits between December 14, 1989 and April 26, 1990. Tephra plumes rose to altitudes of 7 to more than 10 km and were carried mainly northward and eastward by prevailing winds, where they substantially impacted air travel, commerce, and other activities. In comparison to notable eruptions of the recent past, the Redoubt events produced a modest amount of tephra-fall deposits - 6 ?? 107 to 5 ?? 1010 kg for individual events and a total volume (dense-rock equivalent) of about 3-5 ?? 107 m3 of andesite and dacite. Two contrasting tephra types were generated by these events. Pumiceous tephra-fall deposits of December 14 and 15 were followed on December 16 and all later events by fine-grained lithic-crystal tephra deposits, much of which fell as particle aggregates. The change in the character of the tephra-fall deposits reflects their fundamentally different modes of origin. The pumiceous deposits were produced by magmatically driven explosions. The finegrained lithic-crystal deposits were generated by two processes. Hydrovolcanic vent explosions generated tephrafall deposits of December 16 and 19. Such explosions continued as a tephra source, but apparently with diminishing importance, during events of January and February. Ash clouds of lithic pyroclastic flows generated by collapse of actively growing lava domes probably contributed to tephra-fall deposits of all events from January 2 to April 26, and were the sole source of tephra fall for at least the last 4 deposits. ?? 1994.

  5. Distribution and mass of tephra-fall deposits from volcanic eruptions of Sakurajima Volcano based on posteruption surveys

    Science.gov (United States)

    Oishi, Masayuki; Nishiki, Kuniaki; Geshi, Nobuo; Furukawa, Ryuta; Ishizuka, Yoshihiro; Oikawa, Teruki; Yamamoto, Takahiro; Nanayama, Futoshi; Tanaka, Akiko; Hirota, Akinari; Miwa, Takahiro; Miyabuchi, Yasuo

    2018-04-01

    We estimate the total mass of ash fall deposits for individual eruptions of Sakurajima Volcano, southwest Japan based on distribution maps of the tephra fallout. Five ash-sampling campaigns were performed between 2011 and 2015, during which time Sakurajima continued to emit ash from frequent Vulcanian explosions. During each survey, between 29 and 53 ash samplers were installed in a zone 2.2-43 km downwind of the source crater. Total masses of erupted tephra were estimated using several empirical methods based on the relationship between the area surrounded by a given isopleth and the thickness of ash fall within each isopleth. We obtained 70-40,520 t (4.7 × 10-8-2.7 × 10-5-km3 DRE) as the minimum estimated mass of erupted materials for each eruption period. The minimum erupted mass of tephra produced during the recorded events was calculated as being 890-5140 t (5.9 × 10-7-3.6 × 10-6-km3 DRE). This calculation was based on the total mass of tephra collected during any one eruptive period and the number of eruptions during that period. These values may thus also include the contribution of continuous weak ash emissions before and after prominent eruptions. We analyzed the meteorological effects on ash fall distribution patterns and concluded that the width of distribution area of an ash fall is strongly controlled by the near-ground wind speed. The direction of the isopleth axis for larger masses is affected by the local wind direction at ground level. Furthermore, the wind direction influences the direction of the isopleth axes more at higher altitude. While a second maximum of ash fall can appear, the influence of rain might only affect the finer particles in distal areas.

  6. Character, mass, distribution, and origin of tephra-fall deposits from the 2009 eruption of Redoubt Volcano, Alaska: highlighting the significance of particle aggregation

    Science.gov (United States)

    Wallace, Kristi; Coombs, Michelle L; Schaefer, Janet R.

    2013-01-01

    The 2009 eruption of Redoubt Volcano included 20 tephra-producing explosions between March 15, 2009 and April 4, 2009 (UTC). Next-Generation radar (NEXRAD) data show that plumes reached heights between 4.6 km and 19 km asl and were distributed downwind along nearly all azimuths of the volcano. Explosions lasted between 0.8 mm thick), including communities along the Kenai Peninsula (80–100 km) and the city of Anchorage (170 km). Trace ash (mass of tephra-fall deposits at 54.6 × 109 kg with a total DRE volume of 20.6 × 106 m3.

  7. physical volcanology of pyroclastic tephra deposit at batoke mt.

    African Journals Online (AJOL)

    Home

    2013-04-16

    Apr 16, 2013 ... In the deposit three facies types; which are the lava flow, the lapilli and ash ... flow flanked by the tephra pile, the lack of accidental clasts, and the ..... Origin of the Lethal gas ... eruption behaviour and petrochemistry of lava.

  8. Holocene tephra deposits in the northern Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mineralogical and geochemical characteristics of sediments of Core CSH1, which was collected from the northern Okinawa Trough, indicate that large amounts of volcanic materials have deposited in the northern Okinawa Trough during the Holocene. On the basis of down-core variations in mineral and element contents of sediments, two layers in the uppermost section of Core CSH1 characterized by high quartz, Na2O, MnO, K2O, uranium contents and low contents of clay minerals, volatiles, Fe2O3, MgO, CaO and strontium, have been identified as the tephra deposits. Systematic grain-size measurements also suggest that sediments from the northern Okinawa Trough are made up of terrigenous materials and volcanic ashes with different proportion during the Holocene. The sediments of tephra layers in Core CSH1 show bi-modal patterns in grain-size distribution with modal grain-sizes of 74.3 and 7.81 μm,respectively. According to the radiocarbon dating on shells of zooplankton foraminifera, two tephra layers in Core CSH1, formed at 7 250 and 10 870 a BP (cal), approximately correspond to the K-Ah tephra [7 300 a BP (cal)] and the eruption of Kuju Volcano (12~10 ka BP), respectively.

  9. Tephrochronology of the Brooks River Archaeological District, Katmai National Park and Preserve, Alaska: What can and cannot be done with tephra deposits

    Science.gov (United States)

    Riehle, J.R.; Dumond, D.E.; Meyer, C.E.; Schaaf, J.M.

    2000-01-01

    The Brooks River Archaeological District (BRAD) in Katmai National Park and Preserve is a classical site for the study of early humans in Alaska. Because of proximity to the active Aleutian volcanic arc, there are numerous tephra deposits in the BRAD, which are potentially useful for correlating among sites of archaeological investigations. Microprobe analyses of glass separates show, however, that most of these tephra deposits are heterogeneous mixtures of multiple glass populations. Some glasses are highly similar to pyroclasts of Aniakchak Crater (160 km to the south), others are similar to pyroclasts in the nearby Valley of Ten Thousand Smokes, and some are similar to no other tephra samples from the Alaska Peninsula. Moreover, tephra deposits in any one archaeological study site are not always similar to those from nearby sites, indicating inconsistent preservation of these mainly thin, fine-grained deposits. At least 15, late Holocene tephra deposits are inferred at the BRAD. Their heterogeneity is the result of either eruptions of mixed or heterogeneous magmas, like the 1912 Katmai eruption, or secondary mixing of closely succeeding tephra deposits. Because most cannot be reliably distinguished from one another on the basis of megascopic properties, their utility for correlations is limited. At least one deposit can be reliably identified because of its thickness (10 cm) and colour stratification. Early humans seem not to have been significantly affected by these tephra falls, which is not surprising in view of the resilience exhibited by both plants and animals following the 1912 Katmai eruption.

  10. Fate and agricultural consequences of leachable elements added to the environment from the 2011 Cordón Caulle tephra fall

    Science.gov (United States)

    Stewart, Carol; Craig, Heather M.; Gaw, Sally; Wilson, Thomas; Villarosa, Gustavo; Outes, Valeria; Cronin, Shane; Oze, Christopher

    2016-11-01

    The June 2011 eruption of Cordón Caulle volcano, Chile, dispersed tephra over 350,000 km2, including productive agricultural land. This resulted in the death of nearly one million livestock. Two distinct environments were affected: a proximal temperate Andean setting, and the semi-arid Argentine steppe farther from the volcano. The purpose of this study was to better understand the fate and agricultural consequences of leachable elements added to the environment by this large silicic tephra fall. Tephra, soil and surface water samples across the depositional area were collected both immediately after the eruption (tephra and water) and nine months afterwards (tephra, soil and water). Tephra samples were analysed following a new hazard assessment protocol developed by the International Volcanic Health Hazard Network (IVHHN). Water-extractable element concentrations in freshly-collected tephra were very low to low compared to other eruptions, and showed no trends with distance from the volcano. Surface water analyses suggested short-term changes to water composition due to the release of elements from tephra. No effect on the fertility of soils underlying tephra was apparent after nine months. Water-extractable fluorine (F) in freshly-collected tephra ranged from 12 to 167 mg/kg, with a median value of 67 mg/kg. Based on parallels with the 11-12 October 1995 eruption of Ruapehu volcano, New Zealand, we conclude that F toxicity was a possible contributing factor to the large-scale livestock deaths as well as to chronic fluorosis widely reported in wild deer populations across the Cordón Caulle tephra depositional area. Finally, we recommend that effective response to widespread tephra fall over agricultural areas should include: (1) rapid, statistically representative field sampling of tephra, soils, surface water supplies and forage crops; (2) analysis using appropriate and reliable laboratory methods; (3) modelling both short and long-term impacts on the ecosystem

  11. Classifying the Sizes of Explosive Eruptions using Tephra Deposits: The Advantages of a Numerical Inversion Approach

    Science.gov (United States)

    Connor, C.; Connor, L.; White, J.

    2015-12-01

    Explosive volcanic eruptions are often classified by deposit mass and eruption column height. How well are these eruption parameters determined in older deposits, and how well can we reduce uncertainty using robust numerical and statistical methods? We describe an efficient and effective inversion and uncertainty quantification approach for estimating eruption parameters given a dataset of tephra deposit thickness and granulometry. The inversion and uncertainty quantification is implemented using the open-source PEST++ code. Inversion with PEST++ can be used with a variety of forward models and here is applied using Tephra2, a code that simulates advective and dispersive tephra transport and deposition. The Levenburg-Marquardt algorithm is combined with formal Tikhonov and subspace regularization to invert eruption parameters; a linear equation for conditional uncertainty propagation is used to estimate posterior parameter uncertainty. Both the inversion and uncertainty analysis support simultaneous analysis of the full eruption and wind-field parameterization. The combined inversion/uncertainty-quantification approach is applied to the 1992 eruption of Cerro Negro (Nicaragua), the 2011 Kirishima-Shinmoedake (Japan), and the 1913 Colima (Mexico) eruptions. These examples show that although eruption mass uncertainty is reduced by inversion against tephra isomass data, considerable uncertainty remains for many eruption and wind-field parameters, such as eruption column height. Supplementing the inversion dataset with tephra granulometry data is shown to further reduce the uncertainty of most eruption and wind-field parameters. We think the use of such robust models provides a better understanding of uncertainty in eruption parameters, and hence eruption classification, than is possible with more qualitative methods that are widely used.

  12. Thermoluminescence dating of a tephra deposit of the ''Toya'' volcano (Hokkaido, Japan)

    International Nuclear Information System (INIS)

    Sanzelle, S.; Pilleyre, Th.; Miallier, D.; Fain, J.; Ganzawa, Y.

    2000-01-01

    Toya caldera which has a diameter of about 10 km and a hexagonal form is situated in the southern part of Hokkaido, northern Japan. The water level of the caldera lake is 84 m and the highest altitude of the central dome in the lake, Nakajima is 454 m. The volcanic activity is divided into 4 stages of the Toya Pyroclastic Flow Deposits 1 to 4. This tephra is composed of rhyolitic ash which is rich in glass and associated with hornblende, pyroxene and quartz. In a previous work, the age of eruption was estimated by utilising several dating methods and the stratigraphical correlation with other tephra. The ages which resulted from FT (Fission Tracks) dating and TL (Thermoluminescence) dating indicated 130±30 ka and 103-134 ka, respectively. The overall estimated age, received from other information such as the environmental change of mineral marine deposits, has been accepted as 100-120 ka by Quaternary Researchers. Because this tephra can be found widely in the Quaternary field, many researchers can use it as an appropriate age indicator of the 5c or 5d Isotope Stage, the middle age of the Last Internal Glacial Age. A new dating program was initiated, using the red TL of quartz grains extracted from the tephra. The samples studied in the present work came from the southern part of the deposits, around 15 km away from the centre of the caldera. The TL measurements, using the red signal of xenolithic quartz grains from the tephra, were made at Aubiere. Three distinct sets of samples were measured. The first two differ from each other by grain size, 250-350 μm (TOYA2, Aset2) and 150-250 μm (TOYA1,Bset3), and were irradiated in Japan and the third one, 250-350 μm (TOYA2, Cset2) was irradiated at Aubiere. The annual dose rate experienced by the samples during burial was estimated from a compilation of radionuclide contents evaluated in Japan using NAA and in France, using low level gamma spectroscopy (Aubiere) and ICPMS (CRPG, Nancy). In situ water content (as dug

  13. The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary

    Science.gov (United States)

    Riehle, J.R.; Mann, D.H.; Peteet, D.M.; Engstrom, D.R.; Brew, D.A.; Meyer, C.E.

    1992-01-01

    Late Pleistocene tephra deposits found from Sitka to Juneau and Lituya Bay are assigned to a source at the Mount Edgecumbe volcanic field, based on similarity of glass compositions to nearvent deposits and on thinning away from Kruzof Island. The sequence of near-vent layers is basaltic andesite and andesite at the base, rhyolite, and mixed dacite and rhyolite on top. The only breaks in the tephra sequence are two 1-mm-thick silt partings in a lake-sediment core, indicating a depositional interval from basaltic andesite to dacite of no more than about a millennium. Tephra deposits at sites >30 km from the vent are solely dacite and rhyolite and are 10,600 to 11,400 14C yr old based on interpretation of 18 radiocarbon ages, including 5 by accelerator mass spectrometry (AMS). Basaltic andesite and andesite deposits nearer the vent are as much as 12,000 yr old. Discrepancy among radiocarbon ages of upland tephra deposits provisionally correlated as the same grainfall is resolvable within ??2 ?? of analytical uncertainty. Comparison of bulk and AMS ages in one sediment core indicates a systematic bias of +600 to +1100 yr for the bulk ages; correlation of tephra deposits among upland and lacustrine sites implies an additional discrepancy of 200-400 yr between upland (relatively too young) and lacustrine ages. In any case, the Mount Edgecumbe tephra deposits are a widespread, latest Pleistocene stratigraphic marker that serves to emphasize the uncertainty in dating biogenic material from southeastern Alaska. ?? 1992.

  14. Connecting the records: exploiting tephra deposits to help understand abrupt climate change

    Science.gov (United States)

    Davies, S. M.; Abbott, P. M.; Bourne, A. J.; Chapman, M.; Pearce, N. J. G.; Griggs, A. J.; Cook, E.

    2016-12-01

    The causal mechanism of abrupt climate change during the last glacial period remains a key challenge. Although these events are well-documented in a wide range of proxy records, the triggers and drivers remain poorly understood, largely due to the dating uncertainties that prevent the integration of different archives. Unravelling the lead/lag responses (hence cause and effect) between the Earth's climate components is limited by the challenges of synchronising palaeoclimate records on a common timescale. Here we present the potential and the challenges of optimising the use of cryptotephra deposits to precisely correlate the Greenland ice-cores with North Atlantic marine records. A series of new cryptotephra deposits have been identified in Greenland, increasing the scope of identifying coeval isochrons in the marine environment. This new framework, however, brings new challenges in the search for unique and robust geochemical fingerprints for unequivocal tephra correlations. As such, some tephra deposits are proposed to be more valuable than others and underpin key snapshots in time during the last glacial period. The North Atlantic Ash Zone II, for instance, represents the most widespread isochron and constrains the cooling of GI-15. Some tephra deposits in the ice-core record originate from ultra-distal sources beyond the North Atlantic region and we also explore the potential for establishing North Pacific linkages.

  15. Tephra Fallout Hazard Assessment for VEI5 Plinian Eruption at Kuju Volcano, Japan, Using TEPHRA2

    Science.gov (United States)

    Tsuji, Tomohiro; Ikeda, Michiharu; Kishimoto, Hiroshi; Fujita, Koji; Nishizaka, Naoki; Onishi, Kozo

    2017-06-01

    Tephra fallout has a potential impact on engineered structures and systems at nuclear power plants. We provide the first report estimating potential accumulations of tephra fallout as big as VEI5 eruption from Kuju Volcano and calculated hazard curves at the Ikata Power Plant, using the TEPHRA2 computer program. We reconstructed the eruptive parameters of Kj-P1 tephra fallout deposit based on geological survey and literature review. A series of parameter studies were carried out to determine the best values of empirical parameters, such as diffusion coefficient and the fall time threshold. Based on such a reconstruction, we represent probabilistic analyses which assess the variation in meteorological condition, using wind profiles extracted from a 22 year long wind dataset. The obtained hazard curves and probability maps of tephra fallout associated to a Plinian eruption were used to discuss the exceeding probability at the site and the implications of such a severe eruption scenario.

  16. Adjusting particle-size distributions to account for aggregation in tephra-deposit model forecasts

    Science.gov (United States)

    Mastin, Larry G.; Van Eaton, Alexa; Durant, A.J.

    2016-01-01

    Volcanic ash transport and dispersion (VATD) models are used to forecast tephra deposition during volcanic eruptions. Model accuracy is limited by the fact that fine-ash aggregates (clumps into clusters), thus altering patterns of deposition. In most models this is accounted for by ad hoc changes to model input, representing fine ash as aggregates with density ρagg, and a log-normal size distribution with median μagg and standard deviation σagg. Optimal values may vary between eruptions. To test the variance, we used the Ash3d tephra model to simulate four deposits: 18 May 1980 Mount St. Helens; 16–17 September 1992 Crater Peak (Mount Spurr); 17 June 1996 Ruapehu; and 23 March 2009 Mount Redoubt. In 192 simulations, we systematically varied μagg and σagg, holding ρagg constant at 600 kg m−3. We evaluated the fit using three indices that compare modeled versus measured (1) mass load at sample locations; (2) mass load versus distance along the dispersal axis; and (3) isomass area. For all deposits, under these inputs, the best-fit value of μagg ranged narrowly between  ∼  2.3 and 2.7φ (0.20–0.15 mm), despite large variations in erupted mass (0.25–50 Tg), plume height (8.5–25 km), mass fraction of fine ( discrete process that is insensitive to eruptive style or magnitude. This result offers the potential for a simple, computationally efficient parameterization scheme for use in operational model forecasts. Further research may indicate whether this narrow range also reflects physical constraints on processes in the evolving cloud.

  17. Multiple Magma Batches Recorded in Tephra Deposits from the Toba Complex, Sumatra.

    Science.gov (United States)

    Pearce, N. J. G.; Westgate, J.; Gatti, E.

    2015-12-01

    The Toba Caldera Complex is the largest Quaternary caldera on Earth, and has generated three voluminous and compositionally similar rhyolitic tuffs, viz. the Oldest (OTT, 800 ka), Middle (MTT, ~500 ka) and Youngest Toba Tuffs (YTT, 75 ka). These tephra deposits are widespread across Indonesia, Malaysia, South China Sea, Sea of Bengal, India and Indian Ocean and provide useful stratigraphic markers in oceanic, lacustrine and terrestrial environments. Single shard trace element analysis of these deposits reveals the changing availability of different batches of magma through time, with Sr, Ba and Y contents defining 5 discrete magma populations in YTT, 4 populations in MTT and only a single, low Ba population in OTT. Within an individual eruption these populations are clearly distinct, but between eruptions (e.g. MTT and YTT) some of these populations overlap while others do not, indicating both the longevity (and/or continuous supply of fresh material) and evolution of these magma batches in the Toba Complex. Major element compositions of the different groups show equilibration at different pressures (based on Q'-Ab'-Or'), with the equilibration of low Ba populations at ~160 MPa, increasing to depths of ~210 MPa for the highest Ba population. The proportions of different populations of glass in distal YTT shows that relatively little of the high Ba population makes it into the distal record across India, and that this population appears to be over-represented in the proximal free glass and pumice from the caldera walls. This data may shed light on magma availability and tephra dispersal during the YTT eruption. Similarly, the glass composition of individual pumices from proximal deposits record regional, compositional and temporal differences in the erupted products. These show, for example, the apparent mingling of some of the magma batches and also that the high Ba population appears early (i.e. stratigraphically lower) in the northern caldera wall.

  18. ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA

    International Nuclear Information System (INIS)

    C. Harrington

    2004-01-01

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (Ashplume) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. These aspects of volcanism-related dose calculation are described in the context of the entire igneous disruptive events conceptual model in ''Characterize Framework for Igneous Activity'' (BSC 2004 [DIRS 169989], Section 6.1.1). The Ashplume conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The Ashplume mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report update the previous documentation of the Ashplume mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model. In this report, ''Ashplume'' is used when referring to the atmospheric dispersal model and ''ASHPLUME'' is used when referencing the code of that model. Two analysis and model reports provide direct inputs to this model report, namely ''Characterize Eruptive Processes at Yucca Mountain, Nevada and Number of Waste Packages Hit by Igneous Intrusion''. This model report provides direct inputs to

  19. ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    C. Harrington

    2004-10-25

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (Ashplume) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. These aspects of volcanism-related dose calculation are described in the context of the entire igneous disruptive events conceptual model in ''Characterize Framework for Igneous Activity'' (BSC 2004 [DIRS 169989], Section 6.1.1). The Ashplume conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The Ashplume mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report update the previous documentation of the Ashplume mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model. In this report, ''Ashplume'' is used when referring to the atmospheric dispersal model and ''ASHPLUME'' is used when referencing the code of that model. Two analysis and model reports provide direct inputs to this model report, namely ''Characterize Eruptive Processes at Yucca Mountain, Nevada and Number of Waste Packages Hit

  20. Modeled tephra ages from lake sediments, base of Redoubt Volcano, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Schiff, C J; Kaufman, D S; Wallace, K L; Werner, A; Ku, T L; Brown, T A

    2007-02-25

    A 5.6-m-long lake sediment core from Bear Lake, Alaska, located 22 km southeast of Redoubt Volcano, contains 67 tephra layers deposited over the last 8750 cal yr, comprising 15% of the total thickness of recovered sediment. Using 12 AMS {sup 14}C ages, along with the {sup 137}Cs and {sup 210}Pb activities of recent sediment, we evaluated different models to determine the age-depth relation of sediment, and to determine the age of each tephra deposit. The age model is based on a cubic smooth spline function that was passed through the adjusted tephra-free depth of each dated layer. The estimated age uncertainty of the 67 tephras averages {+-} 105 yr (1{sigma}). Tephra-fall frequency at Bear Lake was among the highest during the past 500 yr, with eight tephras deposited compared to an average of 3.7 per 500 yr over the last 8500 yr. Other periods of increased tephra fall occurred 2500-3500, 4500-5000, and 7000-7500 cal yr. Our record suggests that Bear Lake experienced extended periods (1000-2000 yr) of increased tephra fall separated by shorter periods (500-1000 yr) of apparent quiescence. The Bear Lake sediment core affords the most comprehensive tephrochronology from the base of the Redoubt Volcano to date, with an average tephra-fall frequency of once every 130 yr.

  1. Multi-criteria correlation of tephra deposits to source centres applied in the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Hopkins, Jenni L.; Wilson, Colin J. N.; Millet, Marc-Alban; Leonard, Graham S.; Timm, Christian; McGee, Lucy E.; Smith, Ian E. M.; Smith, Euan G. C.

    2017-07-01

    Linking tephras back to their source centre(s) in volcanic fields is crucial not only to reconstruct the eruptive history of the volcanic field but also to understand tephra dispersal patterns and thus the potential hazards posed by a future eruption. Here we present a multi-disciplinary approach to correlate distal basaltic tephra deposits from the Auckland Volcanic Field (AVF) to their source centres using proximal whole-rock geochemical signatures. In order to achieve these correlations, major and trace element tephra-derived glass compositions are compared with published and newly obtained whole-rock geochemical data for the entire field. The results show that incompatible trace element ratios (e.g. (Gd/Yb)N, (La/Yb)N, (Zr/Yb)N) vary widely across the AVF (e.g. (La/Yb)N = 5 to 40) but show a more restricted range within samples from a single volcanic centre (e.g. (La/Yb)N = 5 to 10). These ratios are also the least affected by fractional crystallisation and are therefore the most appropriate geochemical tools for correlation between tephra and whole-rock samples. However, findings for the AVF suggest that each volcanic centre does not have a unique geochemical signature in the field as a whole, thus preventing unambiguous correlation of tephras to source centre using geochemistry alone. A number of additional criteria are therefore combined to further constrain the source centres of the distal tephras including age, eruption scale, and location (of centres, and sites where tephra were sampled). The combination of tephrostratigraphy, 40Ar/39Ar dating and morphostratigraphic constraints allow, for the first time, the relative and absolute ordering of 48 of 53 volcanic centres of the Auckland Volcanic Field to be resolved. Eruption frequencies are shown to vary between 0.13 and 1.5 eruptions/kyr and repose periods between individual eruptions vary from <0.1 to 13 kyr, with 23 of the 48 centres shown to have pre-eruptive repose periods of <1000 years. No spatial

  2. Radiocarbon Ages and Environments of Deposition of the Wono and Trego Hot Springs Tephra Layers in the Pyramid Lake Subbasin, Nevada

    Science.gov (United States)

    Benson, L.V.; Smoot, J.P.; Kashgarian, Michaele; Sarna-Wojcicki, A.; Burdett, J.W.

    1997-01-01

    Uncalibrated radiocarbon data from core PLC92B taken from Wizards Cove in the Pyramid Lake subbasin indicate that the Trego Hot Springs and Wono tephra layers were deposited 23,200 ?? 300 and 27,300 ??300 14C yr B.P. (uncorrected for reservoir effect). Sedimentological data from sites in the Pyramid Lake and Smoke Creek-Black Rock Desert subbasins indicate that the Trego Hot Springs tephra layer was deposited during a relatively dry period when Pyramid Lake was at or below its spill point (1177 m) to the Winnemucca Lake subbasin. The Wono tephra layer was deposited when lake depth was controlled by spill across Emerson Pass sill (1207 m) to the Smoke Creek-Black Rock Desert subbasin. 18O data from core PLC92B also support the concept that the Trego Hot Springs tephra fell into a relatively shallow Pyramid Lake and that the Wono tephra fell into a deeper spilling lake. ?? 1997 University of Washington.

  3. A micromorphological study of pedogenic processes in an evolutionary soil sequence formed in late quaternary rhyolitic tephra deposits, North Island, New Zealand.

    NARCIS (Netherlands)

    Bakker, L.; Lowe, D.J.; Jongmans, A.G.

    1996-01-01

    The influence of time as a soil forming factor was studied on an evolutionary sequence of five soils (1850 radiocarbo years BP-ca. 120,000 BP) developed in rhyolitic tephra deposits in New Zealand. New micromorphological observations were combined with existing macromorphological, chemical,

  4. Geochemical characterization of mid-distal Nisyros tephra on Datça peninsula (southwestern Anatolia)

    Science.gov (United States)

    Gençalioğlu-Kuşcu, Gonca; Uslular, Göksu

    2018-04-01

    We present new distal records of tephra deposits that overly the Kos ignimbrite in seven locations of Datça peninsula. Tephra in one of these locations were previously associated with Nisyros Kyra sub-unit based only on the field characteristics. We use different proxies such as field observations, petrography, mineral, glass, and whole-rock chemistry in order to characterize and correlate the previously and recently identified pumice fall deposits on Datça. The total thickness of the fall deposit reaches to 3.5 m. The size of the pumice clasts is generally within the range of lapilli, and they have vitrophyric texture consisting mainly of plagioclase (andesine to labradorite) with scarce clinopyroxene (diopside to augite), olivine (Fo48-50), amphibole (magnesio-hastingsite), and biotite crystals. Amphibole is a ubiquitous phenocryst in all Datça tephra units and used as a criterion for the correlation. Glass major element analyses by EMPA reveal two different groups with andesitic and dacitic compositions. Difference in silica content (up to ca. 4 wt%) detected in the same specimen also designates the heterogeneity in pumice glass. This heterogeneity in glass composition is also supported by the frequent occurrence of banded pumice clasts in Datça tephra. Whole-rock composition of the pumice is mainly andesitic with calc-alkaline affinity. Multi-element patterns on primitive-mantle normalized diagram display typical arc-magmatism signature (i.e. depletion in Nb, Ta, Ti, and P). In order to check and eliminate the potential alternatives, we compared the distal deposits on Datça not only with Kyra, but also with other Nisyros tephra units. Yet, Kyra is the only unit that has comparable depositional characteristics, calcic amphibole crystals, andesitic-dacitic glass and whole-rock chemistry, and distal tephra deposits on neighboring islands (Tilos and Chalki). Therefore, we associate Datça tephra deposits with some proximal Kyra subunits of intermediate

  5. Tephra, tephrochronology and archaeology

    DEFF Research Database (Denmark)

    Riede, Felix; Thastrup, Mads

    2013-01-01

    increased areas, the overall potential of tephrochronology as a major dating tool for both palaeoenvironmental scientists and archaeologists is greatly expanded. The aim of this paper is not to be comprehensive, but to provide a brief and timely general review of tephra studies and their methodologies......Volcanic eruptions are often, although by no means always, associated with a profuse output of fine pyroclastic material, tephra. While residence time in the atmosphere of the very finest of these particles can be substantial, the deposition of the bulk of volcanic ejecta can be considered...... only act as a useful chronostratigraphic marker, but can also play a role in changing patterns of environmental and cultural change at the level of the site or the region. In order to move towards such integration, a series of methodological challenges have to be met. We outline some of these...

  6. Field-trip guide to Mount St. Helens, Washington - An overview of the eruptive history and petrology, tephra deposits, 1980 pyroclastic density current deposits, and the crater

    Science.gov (United States)

    Pallister, John S.; Clynne, Michael A.; Wright, Heather M.; Van Eaton, Alexa R.; Vallance, James W.; Sherrod, David R.; Kokelaar, B. Peter

    2017-08-02

    This field trip will provide an introduction to several fascinating features of Mount St. Helens. The trip begins with a rigorous hike of about 15 km from the Johnston Ridge Observatory (9 km north-northeast of the crater vent), across the 1980 Pumice Plain, to Windy Ridge (3.6 km northeast of the crater vent) to examine features that document the dynamics and progressive emplacement of pyroclastic flows. The next day, we examine classic tephra outcrops of the past 3,900 years and observe changes in thickness and character of these deposits as we traverse their respective lobes. We examine clasts in the deposits and discuss how the petrology and geochemistry of Mount St. Helens deposits reveal the evolution of the magmatic system through time. We also investigate the stratigraphy of the 1980 blast deposit and review the chronology of this iconic eruption as we travel through the remains of the blown-down forest. The third day is another rigorous hike, about 13 km round trip, climbing from the base of Windy Ridge (elevation 1,240 m) to the front of the Crater Glacier (elevation 1,700 m). En route we examine basaltic andesite and basalt lava flows emplaced between 1,800 and 1,700 years before present, a heterolithologic flow deposit produced as the 1980 blast and debris avalanche interacted, debris-avalanche hummocks that are stranded on the north flank and in the crater mouth, and shattered dacite lava domes that were emplaced between 3,900 and 2,600 years before present. These domes underlie the northern part of the volcano. In addition, within the crater we traverse well-preserved pyroclastic-flow deposits that were emplaced on the crater floor during the summer of 1980, and a beautiful natural section through the 1980 deposits in the upper canyon of the Loowit River.Before plunging into the field-trip log, we provide an overview of Mount St. Helens geology, geochemistry, petrology, and volcanology as background. The volcano has been referred to as a

  7. Rootless tephra stratigraphy and emplacement processes

    Science.gov (United States)

    Hamilton, Christopher W.; Fitch, Erin P.; Fagents, Sarah A.; Thordarson, Thorvaldur

    2017-01-01

    Volcanic rootless cones are the products of thermohydraulic explosions involving rapid heat transfer from active lava (fuel) to external sources of water (coolant). Rootless eruptions are attributed to molten fuel-coolant interactions (MFCIs), but previous studies have not performed systematic investigations of rootless tephrostratigraphy and grain-size distributions to establish a baseline for evaluating relationships between environmental factors, MFCI efficiency, fragmentation, and patterns of tephra dispersal. This study examines a 13.55-m-thick vertical section through an archetypal rootless tephra sequence, which includes a rhythmic succession of 28 bed pairs. Each bed pair is interpreted to be the result of a discrete explosion cycle, with fine-grained basal material emplaced dominantly as tephra fall during an energetic opening phase, followed by the deposition of coarser-grained material mainly as ballistic ejecta during a weaker coda phase. Nine additional layers are interleaved throughout the stratigraphy and are interpreted to be dilute pyroclastic density current (PDC) deposits. Overall, the stratigraphy divides into four units: unit 1 contains the largest number of sediment-rich PDC deposits, units 2 and 3 are dominated by a rhythmic succession of bed pairs, and unit 4 includes welded layers. This pattern is consistent with a general decrease in MFCI efficiency due to the depletion of locally available coolant (i.e., groundwater or wet sediments). Changing conduit/vent geometries, mixing conditions, coolant and melt temperatures, and/or coolant impurities may also have affected MFCI efficiency, but the rhythmic nature of the bed pairs implies a periodic explosion process, which can be explained by temporary increases in the water-to-lava mass ratio during cycles of groundwater recharge.

  8. Petrography and geochemistry of achnelithic tephra from Las Herrerías Volcano (Calatrava volcanic field, Spain): Formation of nephelinitic achneliths and post-depositional glass alteration

    Science.gov (United States)

    Carracedo-Sánchez, M.; Sarrionandia, F.; Arostegui, J.; Errandonea-Martin, J.; Gil-Ibarguchi, J. I.

    2016-11-01

    We present the results of a petrographic and geochemical study carried out on a layer of achnelithic tephra outcropping at the base of the volcanic cone of Las Herrerías (Miocene-Quaternary volcanic region of Campo de Calatrava, Spain). The tephra, with a composition of nephelinite and ash (Pele's tears), achnelith fragments and rare welded achneliths. The achneliths at Las Herrerías were generated in a gas-rich fire fountain that fragmented the magma into micro- to nanometre particles. The low viscosity of the nephelinitic blebs (< 1235 Pa.s) inside the hottest (ca. 900 °C), inner zone of the fountain allowed the development of the characteristic fluidal shapes of these pyroclasts and their welding above the glass transition temperature (533-669 °C). The sideromelane glass of the achneliths, also nephelinitic in composition, is variably altered to palagonite. The palagonitization was isovolumetric and took place in a near closed system at the achnelith scale. Palagonitization involved depletion in the concentration (g/cm3) of all major elements and notable increase in H2O content. The elements liberated by this process formed smectite with an average structural formula comprised between those of beidellite and nontronite end terms: (Na0.01K0.03Ca0.18) (Mg0.22Fe0.16)2 + (Fe0.48Al1.02)3 + (Ti0.18)4 + (Si3.58Al0.42) O10(OH)2. The degree of palagonitization in each achnelith was likely related to the amount of water incorporated by individual clasts at the moment of their deposition in a volcanic maar lake. Afterwards, there was no more water circulation through the achnelithic tephra, which was sealed from water by overlying hydrovolcanic tuff deposits. It was this isolation that made possible the preservation of glass to the present day.

  9. Tephra-Producing Eruptions of Holocene Age at Akutan Volcano, Alaska; Frequency, Magnitude, and Hazards

    Science.gov (United States)

    Waythomas, C. F.; Wallace, K. L.; Schwaiger, H.

    2012-12-01

    Akutan Volcano in the eastern Aleutian Islands of Alaska is one of the most historically active volcanoes in the Aleutian arc (43 eruptions in about the past 250 years). Explosive eruptions pose major hazards to aircraft flying north Pacific air routes and to local infrastructure on Akutan and neighboring Unalaska Island. Air travel, infrastructure, and population in the region have steadily increased during the past several decades, and thus it is important to better understand the frequency, magnitude, and characteristics of tephra-producing eruptions. The most recent eruption was a VEI 2 event on March 8-May 21, 1992 that resulted in minor ash emissions and trace amounts of proximal fallout. Nearly continuous low-level emission of ash and steam is typical of historical eruptions, and most of the historical events have been similar in magnitude to the 1992 event. The most recent major eruption occurred about 1600 yr. B.P. and likely produced the ca. 2-km diameter summit caldera and inundated valleys that head on the volcano with pyroclastic-flow and lahar deposits that are tens of meters thick. The 1600 yr. B.P. eruption covered most of Akutan Island with up to 2.5 m of coarse scoriaceous tephra fall, including deposits 0.5-1 m thick near the City of Akutan. Tephra-fall deposits associated with this eruption exhibit a continuous sequence of black, fine to coarse scoriaceous lapilli overlain by a lithic-rich facies and finally a muddy aggregate-rich facies indicating water involvement during the latter stages of the eruption. Other tephra deposits of Holocene age on Akutan Island include more than a dozen discrete fine to coarse ash beds and 3-6 beds of scoriaceous, coarse lapilli tephra indicating that there have been several additional major eruptions (>VEI 3) of Akutan Volcano during the Holocene. Radiocarbon dates on these events are pending. In addition to tephra falls from Akutan, other fine ash deposits are found on the island that originated from other

  10. New accelerator mass spectrometry radiocarbon ages for the Mazama tephra layer from Kootenay National Park, British Columbia, Canada

    International Nuclear Information System (INIS)

    Hallett, D.J.; Hills, L.V.; Clague, J.J.

    1997-01-01

    Charcoal fragments recovered from the Mazama air-fall tephra layer in cores from Dog and Cobb lakes, Kootenay National Park, British Columbia, yielded accelerator mass spectrometry ages of 6720 ± 70 and 6760 ± 70 14 C years BP, respectively. These two new ages, together with other previously published radiocarbon ages on charcoal and twig fragments from Mazama air-fall deposits, indicate that the climatic eruption of Mount Mazama occurred 6730 ± 40 14 C years BP. (author)

  11. Mass Flux of Tephra Sampled Frequently During the Ongoing Halema`uma`u Eruption (Invited)

    Science.gov (United States)

    Swanson, D.; Wooten, K.; Orr, T. R.

    2009-12-01

    The ongoing summit eruption of Kilauea provides an unparalleled opportunity to track, almost daily, the production of tephra. The eruption began on 19 March 2008, and tephra has been erupted every day since then to the end of August 2009. Most of the time, tephra is ejected quasi-continuously from the vent accompanied by a light gray to white gas plume, occasionally broken by a more vigorous pulse (“brown plume”) richer in ejecta. In early April 2008, an array of 10 plastic buckets was placed within 400 m of the new vent in Halema`uma`u down the prevailing NE wind direction. The configuration of the array, spanning an area of about 73,000 m2, has not changed since then. Buckets are emptied frequently, initially every day and, since summer 2008, on all weekdays. The contents are dried and weighed, and an “average network accumulation rate” is calculated in g/m2/hour. In addition, componentry analyses are made of the >0.5-mm size fraction from a bucket near the vent, in order to categorize the tephra into juvenile and lithic fractions. To estimate the total mass of tephra ejected from the vent for a given collection, we first drew isomass contours for several daily collections and plotted isomass versus square root of area to obtain the total mass of the deposit. From this, we developed an empirical multiplication factor that allows us to estimate, within ~25 percent, the total ejected mass per day in kilograms from the total collected mass in grams. The tephra is a mix of vitric and lithic pyroclasts, mostly ash in size. The vitric clasts, interpreted as juvenile, include Pele’s hair and tears, hollow spherules, dumbbells, pumice, and bits of coarsely vesicular glass. All these clasts were probably produced by weak spattering at the top of the lava column, which has rarely been seen. Especially since fall 2008, some vitric clasts are partly coated with secondary minerals or rock dust. We interpret such clasts as recycled, first erupted during spattering

  12. Probabilistic tephra hazard maps for the Neapolitan area: Quantitative volcanological study of Campi Flegrei eruptions

    Science.gov (United States)

    Mastrolorenzo, G.; Pappalardo, L.; Troise, C.; Panizza, A.; de Natale, G.

    2008-07-01

    Tephra fall is a relevant hazard of Campi Flegrei caldera (Southern Italy), due to the high vulnerability of Naples metropolitan area to such an event. Here, tephra derive from magmatic as well as phreatomagmatic activity. On the basis of both new and literature data on known, past eruptions (Volcanic Explosivity Index (VEI), grain size parameters, velocity at the vent, column heights and erupted mass), and factors controlling tephra dispersion (wind velocity and direction), 2D numerical simulations of fallout dispersion and deposition have been performed for a large number of case events. A bayesian inversion has been applied to retrieve the best values of critical parameters (e.g., vertical mass distribution, diffusion coefficients, velocity at the vent), not directly inferable by volcanological study. Simulations are run in parallel on multiple processors to allow a fully probabilistic analysis, on a very large catalogue preserving the statistical proprieties of past eruptive history. Using simulation results, hazard maps have been computed for different scenarios: upper limit scenario (worst-expected scenario), eruption-range scenario, and whole-eruption scenario. Results indicate that although high hazard characterizes the Campi Flegrei caldera, the territory to the east of the caldera center, including the whole district of Naples, is exposed to high hazard values due to the dominant westerly winds. Consistently with the stratigraphic evidence of nature of past eruptions, our numerical simulations reveal that even in the case of a subplinian eruption (VEI = 3), Naples is exposed to tephra fall thicknesses of some decimeters, thereby exceeding the critical limit for roof collapse. Because of the total number of people living in Campi Flegrei and the city of Naples (ca. two million of inhabitants), the tephra fallout risk related to a plinian eruption of Campi Flegrei largely matches or exceeds the risk related to a similar eruption at Vesuvius.

  13. Kulanaokuaiki Tephra (ca, A.D. 400-1000): Newly recognized evidence for highly explosive eruptions at Kilauea Volcano, Hawai'i

    Science.gov (United States)

    Fiske, R.S.; Rose, T.R.; Swanson, D.A.; Champion, D.E.; McGeehin, J.P.

    2009-01-01

    K??lauea may be one of the world's most intensively monitored volcanoes, but its eruptive history over the past several thousand years remains rather poorly known. Our study has revealed the vestiges of thin basaltic tephra deposits, overlooked by previous workers, that originally blanketed wide, near-summit areas and extended more than 17 km to the south coast of Hawai'i. These deposits, correlative with parts of tephra units at the summit and at sites farther north and northwest, show that K??lauea, commonly regarded as a gentle volcano, was the site of energetic pyroclastic eruptions and indicate the volcano is significantly more hazardous than previously realized. Seventeen new calibrated accelerator mass spectrometry (AMS) radiocarbon ages suggest these deposits, here named the Kulanaokuaiki Tephra, were emplaced ca. A.D. 400-1000, a time of no previously known pyroclastic activity at the volcano. Tephra correlations are based chiefly on a marker unit that contains unusually high values of TiO2 and K2O and on paleomagnetic signatures of associated lava flows, which show that the Kulanaokuaiki deposits are the time-stratigraphic equivalent of the upper part of a newly exhumed section of the Uw??kahuna Ash in the volcano's northwest caldera wall. This section, thought to have been permanently buried by rockfalls in 1983, is thicker and more complete than the previously accepted type Uw??kahuna at the base of the caldera wall. Collectively, these findings justify the elevation of the Uw??kahuna Ash to formation status; the newly recognized Kulanaokuaiki Tephra to the south, the chief focus of this study, is defined as a member of the Uw??kahuna Ash. The Kulanaokuaiki Tephra is the product of energetic pyroclastic falls; no surge- or pyroclastic-flow deposits were identified with certainty, despite recent interpretations that Uw??kahuna surges extended 10-20 km from K??lauea's summit. ?? 2009 Geological Society of America.

  14. Holocene eruption history in Iceland - Eruption frequency vs. Tephra layer frequency

    Science.gov (United States)

    Oladottir, B. A.; Larsen, G.

    2012-12-01

    Volcanic deposits of all kinds are used to reconstruct eruption history of volcanoes and volcanic zones. In Iceland tephra is the ideal volcanic deposit to study eruption history as two out of every three eruptions taking place there during the last 11 centuries have been explosive, leaving tephra as their only product. If eruptions producing both lava and tephra are included three out of every four eruptions have produced tephra. Tephra dispersal and deposition depends on factors such as eruption magnitude, eruption cloud height, duration of eruption and prevailing wind directions at the time of eruption. Several outcrops around a particular volcano must therefore be measured to obtain optimal information of its eruption history. Vegetation in the area of deposition is also of great importance for its preservation. Tephra deposited on un-vegetated land is rapidly eroded by wind and water, and deposits up to few tens of cm thickness may be lost from the record. Such tephra deposited on grassy or forested land is at least partly sheltered from the wind after deposition. Soon after tephra deposition (how soon depends on tephra thickness) the root system of the vegetation creates an even better shelter for the tephra and when this stage is reached the tephra is preserved in the soil for millennia, given that no soil erosion takes place. Vegetation is often boosted in the first years after tephra deposition which in turn helps tephra preservation. A setback of using soil sections for reconstructing Holocene eruption history is the lack of soil at the beginning of the era but for that time period tephra records in lake and marine sediments can be used. When tephra stratigraphy in soil sections is measured to study eruption history and eruption frequency of a volcano it must be kept in mind that what is seen is in fact the tephra layer frequency. One section only shows tephra layers deposited in that location and more importantly only the layers preserved there. The

  15. Analysis of volcanic tephra as a material of environment

    Science.gov (United States)

    Sitek, J.; Dekan, J.; Fang, X.; Xiaoli, P.; Chmielewská, E.

    2012-10-01

    Tephra is a fragmental material produced by volcanic eruption. Here, volcanic tephra deposit from the northeast of China was used for our study. Samples of unaltered tephra are usually composed of feldspar, glass, pyroxene, and olivine. Moreover, these volcanic alteration products also contain Fe oxides, phylosilicates, sulfates, and amorphous Al-Si-bearing material. Six different samples of tephra obtained were analyzed by Mössbauer spectroscopy. A typical Mössbauer spectrum of tephra consists of magnetic and non-magnetic components (magnetic component represents about 11% and non-magnetic component about 89% of spectral area). According to the structural composition, it may be supposed that the magnetic component can be assigned to titanomagnetite. Non-magnetic components contain two quadrupole doublets (Fe2+ species) and one doublet containing Fe3+. According to the measured values of Mössbauer spectra, the first two doublets are very similar with pyroxene, olivine and the third to phylosilicate, aluminosilicate or iron oxide of FeO type. Recently, volcanic tephra was applied as an ecological substance. Special solution was proposed for tephra utilization, especially for phosphate removal from contaminated water.

  16. Tephra from the 1979 soufriere explosive eruption.

    Science.gov (United States)

    Sigurdsson, H

    1982-06-04

    The explosive phase of the 1979 Soufriere eruption produced 37.5 x 10(6) cubic meters (dense-rock equivalent) of tephra, consisting of about 40 percent juvenile basaltic andesite and 60 percent of a nonjuvenile component derived from the fragmentation of the 1971-1972 lava island during phreatomagmatic explosions. The unusually fine grain size, poor sorting, and bimodality of the land deposit are attributed to particle aggregation and the formation of accretionary lapilli in a wet eruption column.

  17. Stratigraphy, age and correlation of middle Pleistocene silicic tephras in the Auckland region, New Zealand : a prolific distal record of Taupo Volcanic Zone volcanism

    International Nuclear Information System (INIS)

    Alloway, B.V.; Westgate, J.; Pillans, B.; Pearce, N.; Newnham, R.; Byrami, M.; Aarburg, S.

    2004-01-01

    Coastal sections in the Auckland region reveal highly carbonaceous and/or highly weathered clay-dominated cover-bed successions with numerous discrete distal volcanic ash (tephra) layers, fluvially reworked siliciclastic (tephric) deposits, and two widely distributed pyroclastic density current (PDC) deposits generated from explosive silicic volcanism within the Taupo Volcanic Zone (TVZ). The younger of the two PDC deposits (informally named Waiuku tephra) is glass-isothermal plateau fission-track (ITPFT) dated at 1.00 ± 0.03 Ma and occurs in a normal polarity interval interpreted as the Jaramillo Subchron. Waiuku tephra is correlated with Unit E sourced from the Mangakino Volcanic Centre of the TVZ. Waiuku tephra can be subdivided into two distinctive units enabling unequivocal field correlation: a lower stratified unit (dominantly pyroclastic surge with fall component) and an upper massive to weakly stratified unit (pyroclastic flow). At many sites in south Auckland, Waiuku tephra retains basal 'surge-like' beds (<1.4 m thickness). This provides clear evidence for primary emplacement and is an exceptional feature considering the c. 200 km this PDC has travelled from its TVZ source area. However, at many other Auckland sites, Waiuku tephra displays transitional sedimentary characteristics indicating lateral transformation from hot, gas-supported flow/surge into water-supported mass flow and hyperconcentrated flow (HCF) deposits. The older PDC deposit is dated at 1.21 ± 0.09 Ma, is enveloped by tephras that are ITPFT-dated at 1.14 ± 0.06 Ma (above) and 1.21 ± 0.06 Ma (below), respectively, and occurs below a short normal polarity interval (Cobb Mountain Subchron) at c. 1.19 Ma. This PDC deposit, correlated with Ongatiti Ignimbrite sourced from the Mangakino Volcanic Centre of TVZ, has laterally transformed from a gas-supported, fine-grained pyroclastic flow deposit at Oruarangi, Port Waikato, into a water-supported volcaniclastic mass flow deposit farther north

  18. Geochemical Characterization of Late Pleistocene and Holocene Tephra Layers from the Basin of Mexico, Central Mexico

    Science.gov (United States)

    Ortega-Guerrero, Beatriz; Newton, Anthony J.

    1998-07-01

    In order to aid palaeoenvironmental research of Late Pleistocene and Holocene deposits of central Mexico, tephra layers collected from the sediments of the Texcoco and Chalco sub-basins, in the southern part of the Basin of Mexico, are geochemically characterized and used as stratigraphic markers. The tephra layers range in composition from basaltic andesites to rhyolites and are calc-alkaline. The tephras range in age from >34,000 to ca. 2600 14C yr B.P. New names are used informally to designate correlated tephras. The Tlahuac tephra is present in Chalco, at a depth of 18 m; in the southeastern part of Texcoco, at a depth of around 10 m; and at the Tlapacoya archaeological site, where it had been mistakenly described as basaltic. This basalt-andesite tephra is dated to at least 34,000 14C yr B.P. The Tlapacoya 1 tephra is dated to between 15,020 ± 450 and 14,430 ± 190 yr B.P. and is present in all Chalco sections. The Tlapacoya 2 tephra corresponds to the previously described "pomez gruesa con fragmentos de andesita" (ca. 14,400 yr B.P.) and is present in all Chalco and Texcoco sections. The likely source of these three tephras is the volcano Popocatepetl. Tephra II at Chalco dates to 12,520 ± 135 yr B.P. and correlates with the Upper Toluca Pumice from Nevado de Toluca volcano. These represent the first geochemical glass-shard analysis of tephras from the Basin of Mexico, and so further research is necessary before a reliable tephrochronology can be established.

  19. Theory for Deducing Volcanic Activity From Size Distributions in Plinian Pyroclastic Fall Deposits

    Science.gov (United States)

    Iriyama, Yu; Toramaru, Atsushi; Yamamoto, Tetsuo

    2018-03-01

    Stratigraphic variation in the grain size distribution (GSD) of plinian pyroclastic fall deposits reflects volcanic activity. To extract information on volcanic activity from the analyses of deposits, we propose a one-dimensional theory that provides a formula connecting the sediment GSD to the source GSD. As the simplest case, we develop a constant-source model (CS model), in which the source GSD and the source height are constant during the duration of release of particles. We assume power laws of particle radii for the terminal fall velocity and the source GSD. The CS model can describe an overall (i.e., entire vertically variable) feature of the GSD structure of the sediment. It is shown that the GSD structure is characterized by three parameters, that is, the duration of supply of particles to the source scaled by the fall time of the largest particle, ts/tM, and the power indices of the terminal fall velocity p and of the source GSD q. We apply the CS model to samples of the Worzel D ash layer and compare the sediment GSD structure calculated by using the CS model to the observed structure. The results show that the CS model reproduces the overall structure of the observed GSD. We estimate the duration of the eruption and the q value of the source GSD. Furthermore, a careful comparison of the observed and calculated GSDs reveals new interpretation of the original sediment GSD structure of the Worzel D ash layer.

  20. FALL3D: A computational model for transport and deposition of volcanic ash

    Science.gov (United States)

    Folch, A.; Costa, A.; Macedonio, G.

    2009-06-01

    FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic ashes and lapilli. The model solves the advection-diffusion-sedimentation (ADS) equation on a structured terrain-following grid using a second-order finite differences (FD) explicit scheme. Different parameterizations for the eddy diffusivity tensor and for the particle terminal settling velocities can be used. The code, written in FORTRAN 90, is available in both serial and parallel versions for Windows and Unix/Linux/Mac X operating systems (OS). A series of pre- and post-process utility programs and OS-dependent scripts to launch them are also included in the FALL3D distribution package. Although the model has been designed to forecast volcanic ash concentration in the atmosphere and ash loading at ground, it can also be used to model the transport of any kind of airborne solid particles. The model inputs are meteorological data, topography, grain-size distribution, shape and density of particles, and mass rate of particle injected into the atmosphere. Optionally, FALL3D can be coupled with the output of the meteorological processor CALMET, a diagnostic model which generates 3-D time-dependent zero-divergence wind fields from mesoscale forecasts incorporating local terrain effects. The FALL3D model can be a tool for short-term ash deposition forecasting and for volcanic fallout hazard assessment. As an example, an application to the 22 July 1998 Etna eruption is also presented.

  1. Tephra and cryptotephra in a 60,000-year-old lacustrine sequence from the Fucino Basin: new insights into the major explosive events in Italy

    Science.gov (United States)

    Di Roberto, Alessio; Smedile, Alessandra; Del Carlo, Paola; De Martini, Paolo Marco; Iorio, Marina; Petrelli, Maurizio; Pantosti, Daniela; Pinzi, Stefania; Todrani, Alessandro

    2018-03-01

    Two cores were sampled in the Fucino Basin (central Apennines, Italy), which represents an extensional intramountain basin filled by Pliocene to Quaternary continental alluvial and lacustrine deposits. The cores were investigated for tephra content and five visible tephras with thickness ranging from 1 to 8 cm were identified. Six additional cryptotephra were identified during the inspection of significant peaks of the magnetic susceptibility curve. Texture and mineralogy of five tephra and six cryptotephra layers were analyzed by means of scanning electron microscope coupled with energy-dispersive X-ray spectrometry system (SEM-EDS) and geochemical measurements were performed by an electron microprobe (EPMA) equipped with five wavelength-dispersive spectrometers (WDS) and using a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) system on single glass shards. The results allowed us to assign tephra and cryptotephra to ten known volcanic eruptions that occurred over the last ca. 60 ka in the Campanian Province (Phlegrean Fields and Ischia Island), the Alban Hills volcanic complex, and Lipari island. In particular, we recognized the deposits of the Monte Epomeo Green Tuff and the Piroclastiti di Catavola eruptions of Ischia, the pre-Campanian Ignimbrite Tlc, the Campanian Ignimbrite and the Neapolitan Yellow Tuff eruptions of the Phlegrean Fields, the Gabellotto-Fiume Bianco eruption of Lipari, and all the four explosive events belonging to the last cycle of volcanic activity of Albano maar (Albano 4-7). Deposits from five of these identified events (i.e., Piroclastiti di Catavola, Gabellotto-Fiume Bianco, Albano 5 and 6 eruptions, and Campanian Ignimbrite) were previously un-reported in the Fucino basin. These findings add new tephra layers to the list of possible tephrochronologic markers in the region and highlight that a comprehensive tephra record may be constructed when the study of cryptotephra layers is included. Moreover, results

  2. Automated statistical matching of multiple tephra records exemplified using five long maar sequences younger than 75 ka, Auckland, New Zealand

    Science.gov (United States)

    Green, Rebecca M.; Bebbington, Mark S.; Cronin, Shane J.; Jones, Geoff

    2014-09-01

    Detailed tephrochronologies are built to underpin probabilistic volcanic hazard forecasting, and to understand the dynamics and history of diverse geomorphic, climatic, soil-forming and environmental processes. Complicating factors include highly variable tephra distribution over time; difficulty in correlating tephras from site to site based on physical and chemical properties; and uncertain age determinations. Multiple sites permit construction of more accurate composite tephra records, but correctly merging individual site records by recognizing common events and site-specific gaps is complex. We present an automated procedure for matching tephra sequences between multiple deposition sites using stochastic local optimization techniques. If individual tephra age determinations are not significantly different between sites, they are matched and a more precise age is assigned. Known stratigraphy and mineralogical or geochemical compositions are used to constrain tephra matches. We apply this method to match tephra records from five long sediment cores (≤ 75 cal ka BP) in Auckland, New Zealand. Sediments at these sites preserve basaltic tephras from local eruptions of the Auckland Volcanic Field as well as distal rhyolitic and andesitic tephras from Okataina, Taupo, Egmont, Tongariro, and Tuhua (Mayor Island) volcanic centers. The new correlated record compiled is statistically more likely than previously published arrangements from this area.

  3. Fall

    OpenAIRE

    Odundo, Magdalene

    2008-01-01

    The monoprint Fall, created in the artist-in-residence studio at Dartmouth College, Hanover, New England, represents a transient yet vivid memory of the season spent walking and re-walking a trail I took to the studio on a daily basis. The work arose spontaneously from a direct and instinctive wish to replicate the ghost imprints left on the trail by the wet and dry weather of that autumn. It also represented a sensationally hopeful political transition of what seemed to be the growth of hope...

  4. FALL3D: A Computational Model for Trans-port and Deposition of Volcanic Ash

    OpenAIRE

    Folch, A.; Costa, A.; Macedonio, G.

    2008-01-01

    FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of 8 volcanic ash. The model solves the advection-diffusion-sedimentation (ADS) equa- 9 tion on a structured terrain-following grid using a second-order Finite Differences 10 (FD) explicit scheme. Different parameterizations for the eddy diffusivity tensor 11 and for the particle terminal settling velocities can be used. The code, written 12 in FORTRAN 90, is available in both serial and parallel ver...

  5. Development of estimation method for tephra transport and dispersal characteristics with numerical simulation technique. Part 2. A method of selecting meteorological conditions and the effects on ash deposition and concentration in air for Kanto-area

    International Nuclear Information System (INIS)

    Hattori, Yasuo; Suto, Hitoshi; Toshida, Kiyoshi; Hirakuchi, Hiromaru

    2016-01-01

    In the present study, we examine the estimation of ground deposition for a real test case, a volcanic ash hazard in Kanto-area with various meteorological conditions by using an ash transport- and deposition-model, fall3d; we consider three eruptions, which correspond to the stage 1 and 3 of Hoei eruption at Mt. Fuji and Tenmei Eruption at Mt. Asama. The meteorological conditions are generated with the 53 years reanalysis meteorological dataset, CRIEPI-RCM-Era2, which has a temporal- and spatial-resolutions of 1 hr and 5 km. The typical and extreme conditions were sampled by using Gumbel plot and an artificial neural network technique. The ash deposition is invariably limited to the west area of the vent, even with the typical wind conditions on summer, while the isopach of ground deposition depicted various distributions, which strongly depends on meteorological conditions. This implies that the concentric circular distribution must not be realistic. Also, a long-term eruption, such as the Hoei eruption during stage 3, yields large deposition area due to the daily variations of wind direction, suggesting that the attention to the differences between daily variation and fluctuations of wind direction on evaluating of volcanic ash risk is vital. (author)

  6. Grain size and shape analysis of the AD 1226 tephra layer, Reykjanes volcanic system

    Science.gov (United States)

    Ösp Magnúsdóttir, Agnes; Höskuldsson, Ármann; Larsen, Guðrún; Tumi Guðmunsson, Magnús; Sigurgeirsson, Magnús Á.

    2014-05-01

    Recent explosive eruptions in Iceland have drawn attention to long range tephra transport in the atmosphere. In Iceland tephra forming explosion eruptions are frequent, due to abundance of water. However, the volcanism on the island is principally basaltic. Volcanism along the Reykjanes Peninsula is divided into five distinct volcanic systems. Volcano-tectonic activity within these systems is periodic, with recurrence intervals in the range of 1 ka. Last volcano-tectonic sequence began around AD 940, shortly after settlement of Iceland, and lasted through AD 1340. During this period activity was characterized by basaltic fissure eruptions. Furthermore, this activity period on the Reykjanes peninsula began within the eastern most volcanic system and gradually moved towards the west across the peninsula. The 1226 eruption was a basaltic fissure eruption with in the Reykjanes volcanic system. The eruption began on land and gradually progressed towards the SW until the volcanic fissure extended into the sea. Water-magma interaction changed the eruption from effusive into explosive forming the largest tephra layer on the peninsula. Due to its close proximity to the Keflavik international airport and that of the capital of Iceland it is important to get an insight into, the characteristics, generation and distribution of such tephra deposits. In this eruption the tephra produced had an approximate volume of 0.1 km3 and covered an area of some 3500 km2 within the 0.5 cm isopach. Total grain size distribution of this tephra layer will be presented along with analysis of principal grain shapes of the finer portion of the tephra layer as a function of distance from the source. The tephra grain size is dominated by particles finer than 1 millimeter with an almost complete absence of large grains independent of distance from the source. Comprehensive understanding of the characteristics of tephra generated in this eruption can help us to understand hazards posed by future

  7. Seasonality of the late Pleistocene Dawson tephra and exceptional preservation of a buried riparian surface in central Yukon Territory, Canada

    Science.gov (United States)

    Froese, Duane G.; Zazula, Grant D.; Reyes, Alberto V.

    2006-07-01

    The late Pleistocene Dawson tephra was deposited by one of the largest Quaternary eruptions in northwestern North America. Its distribution is known sparsely from sites near the source area in southwestern Alaska and central Yukon Territory, where more than 20 occurrences are documented in the Klondike region. Dawson tephra erupted about 25,300C yr BP, near the onset of the last glaciation, and provides a stratigraphic marker across Eastern Beringia. We report radiocarbon ages, paleobotanical data, and cryostratigraphic observations from a new Dawson tephra locale at Goldbottom Creek, in the Klondike region of Yukon Territory, which collectively indicate that the eruption occurred in the late winter or early spring. Multiple, fining-upward tephra-rich ice beds are interpreted as remnants of surface icings, which presently are common in the region during spring. A buried in situ riparian meadow, preserved below the icing and tephra, consists of abundant tufted hair grass ( Deschampsia caespitosa), with interspersed horsetails ( Equisetum cf. palustre) and mosses. Detrital plant remains and preserved in situ grass inflorescences entombed in the icing had expelled their fruits, consistent with a late season surface when the icing was active. The extraordinary thickness of Dawson tephra in central Yukon likely reflects reworking of a winter-deposited tephra by snow melt in the spring following the eruption, indicating that the primary thickness may be overestimated at valley-bottom sites. Winter deposition of the tephra may have, in part, minimized the terrestrial ecological impacts of the eruption on zonal "steppe-tundra" vegetation through the retransportation of tephra from hillslopes to the riparian areas, where the tephra became incorporated into local fluvial systems.

  8. Correlation and stratigraphic eruption age of the pyroclastic flow deposits and wide spread volcanic ashes intercalated in the Pliocene-Pleistocene strata, central Japan

    International Nuclear Information System (INIS)

    Nagahashi, Yoshitaka; Satoguchi, Yasufumi; Yoshikawa, Shusaku

    2000-01-01

    Three pyroclastic flow deposits in the Takayama and Omine area, central Honshu, are correlated to the distal widespread volcanic ashes intercalated in the Plio-Pleistocene boundary strata in central Japan. The correlation is based on these stratigraphic relationships, facies, magnetostratigraphy, petrographic properties such as mineral assemblage, refractive index and chemical composition of the volcanic glasses and orthopyroxene. As the result of these correlation, the eruption age of the proximal pyroclastic flow deposits have become clear. And precise correlation between proximal eruption units and distal depositional units is now possible. Ho-Kd 39 Tephra erupted at about 1.76 Ma, forming a co-ignimbrite ash, which deposited in the Kanto sedimentary basin. Eb-Fukuda Tephra erupted at about 1.75 Ma, and distal volcaniclastic deposit sedimented in the Kinki, Niigata and Kanto sedimentary basins. The eruptional and depositional phase are divided into the stage 1, stage 2 (early), stage 2 (late) and stage 3. Stage 1 is phreato-plinian type eruption phase, forming distal ash fall deposit. Stage 2 (early) is plinian pumice fall, intra-plinian pyroclastic flow and plinian pumice fall eruption phase, forming distal ash fall. Stage 2 (late) is final eruptional phase of the biggest pyroclastic flow of the Eb-Fukuda Tephra, forming a co-ignimbrite ash fall. Stage 3 is resedimented stage after the end of the explosive eruption. It is notable that resedimented volcaniclastic deposit reached Osaka sedimentary basin 300 km away from the eruption center. Om-SK110 Tephra erupted at about 1.65 Ma, divided into the stage 1, stage 2 and stage 3. Stage 1 is eruption phase of the plinian pumice fall and first pyroclastic flow. Stage 2 is pauses in eruption activity. Stage 3 is second pyroclastic flow phase, it is inferred that the pyroclastic flow of the stage 3 directly entered the Niigata sedimentary basin and simultaneously formed a co-ignimbrite ash. (author)

  9. ERUPTION TO DOSE: COUPLING A TEPHRA DISPERSAL MODEL WITHIN A PERFORMANCE ASSESSMENT FRAMEWORK

    International Nuclear Information System (INIS)

    G. N. Keating, J. Pelletier

    2005-01-01

    The tephra dispersal model used by the Yucca Mountain Project (YMP) to evaluate the potential consequences of a volcanic eruption through the waste repository must incorporate simplifications in order to function within a large Monte-Carlo style performance assessment framework. That is, the explicit physics of the conduit, vent, and eruption column processes are abstracted to a 2-D, steady-state advection-dispersion model (ASHPLUME) that can be run quickly over thousands of realizations of the overall system model. Given the continuous development of tephra dispersal modeling techniques in the last few years, we evaluated the adequacy of this simplified model for its intended purpose within the YMP total system performance assessment (TSPA) model. We evaluated uncertainties inherent in model simplifications including (1) instantaneous, steady-state vs. unsteady eruption, which affects column height, (2) constant wind conditions, and (3) power-law distribution of the tephra blanket; comparisons were made to other models and published ash distributions. Spatial statistics are useful for evaluating differences in these model output vs. results using more complex wind, column height, and tephra deposition patterns. However, in order to assess the adequacy of the model for its intended use in TSPA, we evaluated the propagation of these uncertainties through FAR, the YMP ash redistribution model, which utilizes ASHPLUME tephra deposition results to calculate the concentration of nuclear waste-contaminated tephra at a dose-receptor population as a result of sedimentary transport and mixing processes on the landscape. Questions we sought to answer include: (1) what conditions of unsteadiness, wind variability, or departure from simplified tephra distribution result in significant effects on waste concentration (related to dose calculated for the receptor population)? (2) What criteria can be established for the adequacy of a tephra dispersal model within the TSPA

  10. First identification and characterization of Borrobol-type tephra in the Greenland ice cores

    DEFF Research Database (Denmark)

    Cook, Eliza; Davies, Siwan M.; Guðmundsdóttir, Esther R.

    2018-01-01

    in the ice-cores or that it relates to just one of the ice-core events. A firm correlation cannot be established at present due to their strong geochemical similarities. The older tephra horizon, found within all three ice-cores and dated to 17326 ± 319 a b2k, can be correlated to a known layer within marine....... The older deposit is consistent with BT age estimates derived from Scottish sites, while the younger deposit overlaps with both BT and PT age estimates. We suggest that either the BT in Northern European terrestrial sequences represents an amalgamation of tephra from both of the GI-1e events identified...

  11. Stratigraphic and compositional complexities of the late Quaternary Lethe tephra in South-central Alaska

    Science.gov (United States)

    Riehle, J.R.; Ager, T.A.; Reger, R.D.; Pinney, D.S.; Kaufman, D.S.

    2008-01-01

    Recently discovered Lethe tephra has been proposed as a latest Pleistocene marker bed in Bristol Bay lowland NE to the Cook Inlet region, Alaska, on the basis of correlations involving a single "Lethe average" glass composition. Type deposits in the Valley of Ten Thousand Smokes, however, are chemically heterogeneous-individual lapilli as well as aggregate ash deposits have glass compositions that range from the average mode to much higher SiO2 and K2O. Moreover, a lake-sediment core from the Cook Inlet region contains one ash deposit similar to "Lethe average" and other, closely underlying deposits that resemble a mixture of the average mode and high-Si high-K mode of proximal deposits. Synthesis of previously published radiocarbon ages indicates a major eruption mainly of "Lethe average" mode about 13,000 14C yr BP. As many as six deposits in the Cook Inlet region-five chiefly "Lethe average" mode-range from about 13,000 to 15-16,000 14C yr BP, and an early Holocene deposit in the Bristol Bay lowland extends the minimum age range of Lethe tephra throughout this region to 8000 14C yr BP. Because of the appearance of "Lethe average" composition in multiple deposits spanning thousands of years, we urge caution when using a Lethe-like composition as a basis for inferring a latest Pleistocene age of a tephra deposit in south-central Alaska. Linear variation plots suggest that magma mixing caused the Lethe heterogeneity; multiple magmas were involved as well in other large pyroclastic eruptions such as Katmai (Alaska) and Rotorua (New Zealand). Lethe is an example of a heterogeneous tephra that may be better compared with other tephras by use of plots of individual analytical points rather than by calculating similarity coefficients based on edited data. ?? 2006 Elsevier Ltd and INQUA.

  12. Collaborative Cyber-infrastructures for the Management of the UNESCO-IGCP Research Project "Forecast of tephra fallout"

    Science.gov (United States)

    Folch, A.; Costa, A.; Cordoba, G.

    2009-04-01

    Tephra fallout following explosive volcanic eruptions produces several hazardous effects on inhabitants, infrastructure, and property and represents a serious threat for communities located around active volcanoes. In order to mitigate the effects on the surrounding areas, scientists and civil decision-making authorities need reliable short-term forecasts during episodes of eruptive crisis and long-term probabilistic maps to plan territorial policies and land use. Modelling, together with field studies and volcano monitoring, constitutes an indispensable tool to achieve these objectives. The UNESCO-IGCP research project proposal "Forecast of tephra fallout" has the aim to produce a series of tools capable to elaborate both short-term forecasts and long-term hazard assessments using the cutting-edge models for tephra transport and sedimentation. A special project website will be designed to supply a set of models, procedures and expertise to several Latino-American Institutes based in countries seriously threatened by this geo-hazard (Argentina, Chile, Colombia, Ecuador, Mexico, and Nicaragua). This will proportionate to the final users a tool to elaborate short-term forecasts of tephra deposition on the ground, and determine airborne ash concentrations (a quantity of special relevance for aerial navigation safety) during eruptions and emergencies. The project web-site will have a public section and a password-protected area to exchange information and data among participants and, eventually, to allow remote execution of high-resolution mesoscale meteorological forecasts at the BSC facilities. The public website section will be updated periodically and will include sections describing the project objectives and achievements as well as the hazard maps for the investigated volcanoes, and will be linked to other relevant websites such as IAVCEI, IGCP, IUGS and UNESCO homepages. A part of the public section of the website will be devoted to disseminate achieved

  13. Tephras in lacustrine sediments of the Sarliève marsh (French Massif Central): age and preservation

    Science.gov (United States)

    Fourmont, Agathe; Macaire, Jean-Jacques; Bréhéret, Jean-Gabriel; Argant, Jacqueline; Prat, Béatrice; Vernet, Gérard

    2006-12-01

    The Sarliève marsh sediments (Massif Central, France) contain two tephras. The first tephra [ 13.7±0.4ka(2δ), ca. 12 000 BP], regionally well known, enables to date the beginning of lacustrine infill to the Lateglacial. The second tephra, the 'tephra de Sarliève', the emitting volcano of which is unknown, would be dated to around the Early Subboreal from pollen data. This occurrence, after the discovery of the 'tephra de Beaunit', emphasizes that volcanic eruption(s) occurred in the 'Chaîne des Puys' or in the volcanic Cézallier more than 1000 years after the last known eruption (Pavin) in the 'Chaîne des Puys' at around 6.6/6.7 ka (5800/5900 BP). In the Sarliève piles, these tephras, well preserved in thick and more silicated deposits of deltas, were not observed in carbonated basin sediments where they were altered. The abundance of authigenic zeolites formed during the Lateglacial in restricted depocentre lacustrine waters allows us to detect initial CF1 tephra occurrence. To cite this article: A. Fourmont et al., C. R. Geoscience 338 (2006).

  14. Eruptive history and magmatic stability of Erebus volcano, Antarctica: Insights from englacial tephra

    Science.gov (United States)

    Iverson, N. A.; Kyle, P. R.; Dunbar, N. W.; Pearce, N. J.

    2012-12-01

    Erebus is the most active volcano in Antarctica and hosts a persistent convecting and degassing phonolite lava lake in its summit crater. Small Strombolian eruptions occasionally eject volcanic bombs onto the crater rim and floor. 40 years of observations, during the austral summer, show that ash eruptions are rare, but extensive records of small tephra (volcanic ash) layers are found embedded in ablating blue ice areas on the flanks of the volcano. Most tephra are deposited within 15km of the summit, although 3 Erebus phonolite tephra have been located over 200km away. The tephra provide a stratigraphic eruptive sequence of Erebus and gives insight into its explosive history. There is very little age control on the eruptions but based on their phonolitic composition they likely span the past 10-40ka. SEM images and Image Particle Analysis (IPA) of tephra were used to determine shard morphology and shape parameters, respectively. The tephra layers characterized by Pele's hair, glass spheres and budding ash are interpreted to be from Strombolian eruptions. In contrast, layers that are dominated by chemical pitting, quenched textures, mossy and adhering particles are mostly likely from phreatomagmatic eruptions. IPA parameters are characterized by rectangularity, compactness, elongation and circularity. Strombolian particles have larger elongation and circularity values exhibited by their stretched and irregular shape and lower rectangularity and compactness values. Phreatomagmatic tephra are more blocky and have higher rectangularity and compactness values and lower elongation and circularity values than Strombolian particles. Based on imagery, many Erebus tephra layers appear to contain a mixture of Strombolian and phreatomagmatic fragments. These mixed eruptions would likely start as phreatomagmatic and transition into magmatic Strombolian eruptions as the water source is exhausted. Major and trace element analyses of the glass shards were measured by electron

  15. Late Miocene marine tephra beds : recorders of rhyolitic volcanism in North Island, New Zealand

    International Nuclear Information System (INIS)

    Shane, P.; Black, T.; Eggins, S.; Westgate, J.

    1998-01-01

    A deep-sea sequence of 72 rhyolitic tephra beds, now exposed at Mahia Peninsula in the Hawke's Bay region of the east coast, North Island, New Zealand, provides a record of Late Miocene volcanism of the Coromandel Volcanic Zone (CVZ): the precursor to large-scale explosive volcanism of the Quaternary Taupo Volcanic Zone (TVZ). The geochemical signature of the glasses in the Miocene tephra has been protected from hydrothermal alteration and prolonged subaerial exposure that have affected proximal CVZ deposits. The tephra beds are primarily eruption-driven sediment gravity flows that have been emplaced into a trench-slope basin, some 300 km from active volcanoes. Their occurrence is consistent with long-distance fluvial transport followed by a point-source discharge into the deep-sea environment, and has no implications for the paleogeographic location of the basins relative to the volcanic arc. The tephra beds are calc-alkaline rhyolites with SiO 2 contents in the range 72-78 wt% (recalculated on a volatile-free basis), and are broadly similar to glassy rocks of the CVZ. Their major oxide, trace element, and REE compositions are indistinguishable from glasses of TVZ rhyolites. The trace element and REE compositional variability in the Late Miocene tephra beds, which were erupted over an estimated duration of c. 0.5-2.4 m.y. is no greater than that of large silicic eruptives of the last 350 ka, and is suggestive of a long-lived source and/or similar magmatic processes. However, the individual tephra beds are products of discrete homogeneous magma batches. New fission track ages of the Miocene tephra beds suggest the main period of volcaniclastic deposition occurred in the interval c. 9-7 Ma. This corresponds well with the initiation of rhyolitic volcanism in the CVZ at c. 10 Ma, and a major period of caldera formation that took place to c. 7 Ma. The ages suggest a sediment accumulation rate of between 0.23 and 1.2 m/ka (av. 0.4 m/ka), and a frequency of eruption of

  16. Improvements in the chronology, geochemistry and correlation techniques of tephra in Antarctic ice

    Science.gov (United States)

    Iverson, N. A.; Dunbar, N. W.; McIntosh, W. C.; Pearce, N. J.; Kyle, P. R.

    2013-12-01

    Visible and crypto tephra layers found in West Antarctic ice provide an excellent record of Antarctic volcanism over the past 100ka. Tephra layers are deposited almost instantaneously across wide areas creating horizons that, if found in several locations, provide 'pinning points' to adjust ice time scales that may otherwise be lacking detailed chronology. Individual tephra layers can have distinct chemical fingerprints allowing them to correlate over great distances. Advances in sample preparation, geochemical analyses (major and trace elements) of fine grained tephra and higher precision 40Ar/39Ar dating of young (typically too small to be directly dated by 40Ar/39Ar method, making it very important to geochemically correlate these layers to proximal deposits where more and larger feldspar can be sampled. The correlation of WDC06A-2767.117 to the coarse, proximal BIT-152 provides one such link. The New Mexico Geochronology Research Lab (NMGRL) has two new multi-collector ARGUS VI mass spectrometers that can provide single crystal laser fusion ages that are approximately an order of magnitude more precise than the previous determinations. With these advancements in analytical technology, we hope to improve precision on 'pinning points' in the deep ice cores where annual layer counting becomes less precise.

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

    Science.gov (United States)

    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 (pangaea.de" target="_blank">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.

  18. Best-practice checklists for tephra collection, analysis and reporting - a draft consensus from the Tephra 2014 workshop

    Science.gov (United States)

    Wallace, K.; Bursik, M. I.; Kuehn, S. C.

    2015-12-01

    The Tephra 2014 Workshop (3-7 August 2014) discussed major developments, best practices, future directions, and critical needs in tephra studies from both volcanological and tephrochronological perspectives. In a consensus-seeking session held at the end of the workshop, the international group of over 70 tephra scientists focused on two complementary themes: (A) the need for common best practices in tephra data collection and reporting among different scientific disciplines, and (B) the need to establish common, accessible mechanisms for tephra data archiving and retrieval. Tephra is the focus of a wide range of research in volcanology, petrology, tephrochronology and tephrostratigraphy (with applications in studies of environmental/climate change, surface processes, paleolimnology, etc.), ash dispersion and fallout modeling, and archaeology, paleoanthropology, and human origins. Researchers in each field have specific objectives that may or may not overlap. The focus on best practices is a first step towards standardized protocols for the collection, analysis and reporting of tephra data across and within disciplines. Such uniformity will facilitate the development and population of useful tephra databases. Current initiatives include the development of best practice checklists as a starting point for ensuring uniformity and completeness. The goals of the checklists are to: 1) ensure consistency among tephra scientists, regardless of research focus, 2) provide basic, comprehensible, metadata requirements, especially those who collect tephra as a peripheral part of their research, 3) help train students, and 4) help journal editors to know which essential metadata should be included in published works. Consistency in tephra sample collection, analysis, and reporting attained by use of these checklists should ultimately aid in improving correlation of tephras across geographically large areas, and facilitate collaborative tephra research. Current and future

  19. Using Spectroscopy to Infer the Eruption Style and Volatile History of Volcanic Tephras

    Science.gov (United States)

    McBride, M. J.; Horgan, B. H. N.; Rowe, M. C.; Wall, K. T.; Oxley, B. M.

    2017-12-01

    The interaction between volatiles and magma strongly influences volcanic eruption styles, and results in an increase in the glass component of volcanic tephra. On Earth, both phreatomagmatic and magmatic explosive eruptions create glassy tephras. Phreatomagmatic eruptions form abundant glass by quickly quenching lava through interaction with meteoric water while magmatic eruptions create less glass through slower cooling within larger pyroclasts or eruption columns. Wall et al. (2014) used X-ray diffraction (XRD) of diverse tephra samples to show that glass content correlates with eruption style, as magmatic samples contain less glass than phreatomagmatic samples. While use of XRD is limited to Earth and the Curiosity rover on Mars, orbital spectroscopy is much a more common technique in the exploration of terrestrial bodies. In this study, we evaluate whether or not spectroscopy can be used to infer eruption style and thus volatile history. Visible/near-infrared (VNIR) and thermal-infrared (TIR) spectra were collected of the Wall et al. (2014) tephra samples, and were analyzed for trends related to glass content and thus eruption style. VNIR spectra can detect glass at high abundances as well as hydrothermal alteration minerals produced during interactions with meteoric water. Using TIR, glass abundances can be derived by deconvolving the spectra with a standard spectral library; however, due to the non-unique spectral shape of glass, intermediate to high glass abundances in tephras are difficult to differentiate using TIR alone. Synthetic mixtures of glass and crystalline minerals verify these results. Therefore, the most effective method for determining glass abundance and thus eruption style from volcanic deposits is a combination of VNIR and TIR spectral analysis. Using standard planetary remote sensing instrumentation to infer eruption styles will provide a new window into the volcanic and volatile histories of terrestrial bodies.

  20. A volcanic event forecasting model for multiple tephra records, demonstrated on Mt. Taranaki, New Zealand

    Science.gov (United States)

    Damaschke, Magret; Cronin, Shane J.; Bebbington, Mark S.

    2018-01-01

    Robust time-varying volcanic hazard assessments are difficult to develop, because they depend upon having a complete and extensive eruptive activity record. Missing events in eruption records are endemic, due to poor preservation or erosion of tephra and other volcanic deposits. Even with many stratigraphic studies, underestimation or overestimation of eruption numbers is possible due to mis-matching tephras with similar chemical compositions or problematic age models. It is also common to have gaps in event coverage due to sedimentary records not being available in all directions from the volcano, especially downwind. Here, we examine the sensitivity of probabilistic hazard estimates using a suite of four new and two existing high-resolution tephra records located around Mt. Taranaki, New Zealand. Previous estimates were made using only single, or two correlated, tephra records. In this study, tephra data from six individual sites in lake and peat bogs covering an arc of 120° downwind of the volcano provided an excellent temporal high-resolution event record. The new data confirm a previously identified semi-regular pattern of variable eruption frequency at Mt. Taranaki. Eruption intervals exhibit a bimodal distribution, with eruptions being an average of 65 years apart, and in 2% of cases, centuries separate eruptions. The long intervals are less common than seen in earlier studies, but they have not disappeared with the inclusion of our comprehensive new dataset. Hence, the latest long interval of quiescence, since AD 1800, is unusual, but not out of character with the volcano. The new data also suggest that one of the tephra records (Lake Rotokare) used in earlier work had an old carbon effect on age determinations. This shifted ages of the affected tephras so that they were not correlated to other sites, leading to an artificially high eruption frequency in the previous combined record. New modelled time-varying frequency estimates suggest a 33

  1. Atmospheric Despersal and Disposition of Tephra From a Potential Volcanic Eruption at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    G. Keating; W.Statham

    2004-01-01

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (ASHPLUME) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. The ASHPLUME conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The ASHPLUME mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report will improve and clarify the previous documentation of the ASHPLUME mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model

  2. Atmospheric Dispersal and Dispostion of Tephra From a Potential Volcanic Eruption at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    G. Keating; W.Statham

    2004-02-12

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (ASHPLUME) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. The ASHPLUME conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The ASHPLUME mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report will improve and clarify the previous documentation of the ASHPLUME mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model.

  3. Stratigraphy and tephra of the Kibish Formation, southwestern Ethiopia.

    Science.gov (United States)

    Brown, Francis H; Fuller, Chad R

    2008-09-01

    The Kibish Formation in southwestern Ethiopia, with an aggregate thickness of approximately 105 m, consists of lacustrine, marginal lacustrine, and deltaic deposits. It is divided into four members numbered I to IV on the basis of erosion surfaces (disconformities) between the strata of each member. It overlies the Mursi and Nkalabong formations, the latter of which is here shown to correlate with the Shungura Formation. Tephra layers in each member allow for secure correlation between geographically separated sections on the basis of the composition of their volcanic glass. Members I, III, and IV of the Kibish Formation appear to have been deposited at the same times as sapropels S7 (197 ka), S4 (104 ka), and S1 (8 ka) in the eastern Mediterranean Sea, respectively. We correlate the KHS Tuff of the Kibish Formation with a >154-kyr-old unnamed tuff in the Konso Formation. Tephra in Member IV may derive from Mount Wenchi, a volcano situated on the divide between the Omo and Blue Nile drainage basins. Thin-bedded sedimentary layers probably represent annual deposition reflecting rapid sedimentation (approximately 30 m/kyr) of parts of the formation. This conclusion is supported by variation in paleomagnetic inclination through a sequence of these layers at KHS. Two fossils of early Homo sapiens (Omo I and Omo II) derive from Member I. Their stratigraphic placement is confirmed by analysis of the KHS Tuff in the lower part of Member II at both fossil sites. The KHS Tuff lies above a disconformity, which itself lies above the fossils at both sites. (40)Ar/(39)Ar dates provide an estimated age of approximately 195 kyr for these fossils. Omo III, a third fossil H. sapiens, probably also derives from Member I of the Kibish Formation and is of similar age. Hominin fossils from AHS, a new site, also derive from Member I. Hominin fossils from CHS can only be placed between 104 ka and 10 ka, the H. sapiens specimen from JHS is most likely 9-13 kyr in age, and a partial

  4. Detection of Lateglacial distal tephra layers in the Netherlands

    NARCIS (Netherlands)

    Davies, S.M.; Hoek, W.Z.; Bohncke, S.J.P.; Lowe, J.; Pyne O'Donnle, S.; Turney, C.S.M.

    2005-01-01

    Three distal tephra layers or cryptotephras have been detected within a sedimentary sequence from the Netherlands that spans the last glacial-interglacial transition. Geochemical analyses identify one as the Vedde Ash, which represents the southernmost discovery of this mid-Younger Dryas tephra so

  5. Correlating tephras and cryptotephras using glass compositional analyses and numerical and statistical methods: Review and evaluation

    Science.gov (United States)

    Lowe, David J.; Pearce, Nicholas J. G.; Jorgensen, Murray A.; Kuehn, Stephen C.; Tryon, Christian A.; Hayward, Chris L.

    2017-11-01

    We define tephras and cryptotephras and their components (mainly ash-sized particles of glass ± crystals in distal deposits) and summarize the basis of tephrochronology as a chronostratigraphic correlational and dating tool for palaeoenvironmental, geological, and archaeological research. We then document and appraise recent advances in analytical methods used to determine the major, minor, and trace elements of individual glass shards from tephra or cryptotephra deposits to aid their correlation and application. Protocols developed recently for the electron probe microanalysis of major elements in individual glass shards help to improve data quality and standardize reporting procedures. A narrow electron beam (diameter ∼3-5 μm) can now be used to analyze smaller glass shards than previously attainable. Reliable analyses of 'microshards' (defined here as glass shards T2 test). Randomization tests can be used where distributional assumptions such as multivariate normality underlying parametric tests are doubtful. Compositional data may be transformed and scaled before being subjected to multivariate statistical procedures including calculation of distance matrices, hierarchical cluster analysis, and PCA. Such transformations may make the assumption of multivariate normality more appropriate. A sequential procedure using Mahalanobis distance and the Hotelling two-sample T2 test is illustrated using glass major element data from trachytic to phonolitic Kenyan tephras. All these methods require a broad range of high-quality compositional data which can be used to compare 'unknowns' with reference (training) sets that are sufficiently complete to account for all possible correlatives, including tephras with heterogeneous glasses that contain multiple compositional groups. Currently, incomplete databases are tending to limit correlation efficacy. The development of an open, online global database to facilitate progress towards integrated, high

  6. New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

    Science.gov (United States)

    Coble, Matthew A.; Burgess, Seth D.; Klemetti, Erik W.

    2017-09-01

    Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate

  7. Testing Proposed Correlations Between Olduvai Gorge and Laetoli, Tanzania Using Tephra Composition

    Science.gov (United States)

    McHenry, L. J.

    2006-12-01

    Olduvai Gorge and Laetoli are well-known Plio-Pleistocene archaeological sites located 30 km apart in Tanzania. Both received volcanic input from the nearby Ngorongoro Volcanic Highlands (NVH), and together provide a sedimentary and volcanic record from about 4.3 Ma to the Holocene. Previous researchers have proposed likely temporal correlations between the two sites, using both faunal and volcanic evidence. Direct tephra correlation between these sites could create a regional stratigraphic framework for their fossil and paleoecological records. Here, one of the proposed correlations is tested using geochemical fingerprinting. The fossiliferous Laetolil and Ndolanya beds of Laetoli predate the deposition of the Olduvai Beds, however recent 39Ar/40Ar SCLF age dating has shown potential temporal overlap between the Naibadad (2.23-1.93 +/- 0.02; Mangea, 1993) and Olpiro Beds (2.06-2.01 +/- 0.03; Manega 1993) at Laetoli with the Naabi Ignimbrite (2.029 +/- 0.005 Ma, Walter et al. 1992) and lower Bed I at Olduvai. Both the Naibadad bed and lower Bed I also contain fresh quartz-bearing tephra, which can be used for geochemical correlation. Three Naibadad tuffs and five lower Bed I tuffs (Naabi Ignimbrite, coarse feldspar crystal tuff (CFCT), Tuff IA, and two ignimbrites near Ngorongoro) were analyzed by electron microprobe for phenocryst and glass composition and compared to test for possible correlations. Certain mineralogical features made such a correlation unlikely. None of the lower Bed I tuffs analyzed contain significant plagioclase, which is present in all of the Naibadad tuffs analyzed. One Naibadad tuff has a bimodal glass composition indistinguishable from the CFCT, however the CFCT is rich in hornblende, while this Naibadad tuff contains none. This mineralogical difference highlights the need for mineralogical in addition to glass geochemical data for tephra correlation. Ngorongoro crater is the likely source for the Naibadad and lower Bed I tuffs because it

  8. Does Thermal Granulation Drive Tephra Jets?

    Science.gov (United States)

    White, J. D.; Zimanowski, B.; Buettner, R.; Sonder, I.; Dellino, P.

    2011-12-01

    Surtseyan tephra jets, also called cypressoid or cock's tail plumes, comprise a characteristic mixture of ash with bombs travelling roughly ballistic paths that tip the individual fingers of the projecting jet. Jets of similar form but smaller scale are generated by littoral magma-water interactions, confirming the general inference that surtseyan tephra jets are a characteristic product of explosive magma-water interaction, and suggesting that magmatic volatiles play a subsidiary role, if any, in their formation. Surtseyan jets have been inferred to result from both intense fuel-coolant interactions, and from simple boiling of water entrained into rising magma, and little new information has become available to test these two positions since they were clearly developed in the 1980s. Recent experiments in which magma is poured into standing water have produced vigorous jetting of hot water as melt solidifies and undergoes extensive thermal granulation. We present high-resolution hi-speed video of these jets, which we see as having the following origin. As thermal granulation takes place, a fracture network advances into the melt/glass body, and water invading the cracks at the rate of propagation is heated nearly instantaneously. Vapor produced at the contact expands and drives outward through cooled cracks, condensing as it moves to the exterior of the magma body where it is emitted as a jet of hot water. In ocean ridge hydrothermal systems a diffuse crack network inducts cold water, which is heated and expelled in focused jets. Focusing of hot outflow in experiments is inferred to result, as suggested for ridge hydrothermal systems, from thermoelastic closure of cracks near the one(s) feeding the jet. From the cooled products of our experimental runs, we know that thermal contraction produces a network of curved cracks with modal spacing of 1-2 mm, which separate domains of unbroken glass. It is during growth of this crack network that cold water enters, is

  9. The 1845 Hekla eruption: Grain-size characteristics of a tephra layer

    Science.gov (United States)

    Gudnason, Jonas; Thordarson, Thor; Houghton, Bruce F.; Larsen, Gudrun

    2018-01-01

    The 1845 eruption is commonly viewed as a typical Hekla eruption. It is a key event in the eruptive history of the volcano, as it is one of the best documented Hekla eruptions, in terms of contemporary accounts and observations. The eruption started on 2 September 1845 with an intense, hour long explosive Plinian phase that passed into effusive activity, ending on the 16 March 1846. The amount of tephra produced in the opening phase was 0.13 km3/7.5 × 1010 kg. The total grain-size distribution of the deposit is bimodal with a dominant coarse mode at - 2.5 φ (5.6 mm) and a broad finer mode at 3 to 4.5 φ (0.125 to 0.045 mm). At individual sites, the grain-size distribution of the tephra from the Plinian opening phase is also commonly (not always) bimodal. Deconvolved grain-size distributions exhibit distinctly different sedimentation patterns of the coarse and fine subpopulations. The lapilli-dominated subpopulation fines rapidly with transport, while the ash-dominated subpopulation shows less changes with distance, indicating premature sedimentation of fines by aggregation from the 1845 volcanic plume. Tephra deposition was to the ESE of the volcano from a 19 km (a.s.l.) high eruption plume. The plume front travelled at speeds of 16-19 m s- 1. Reports of ash deposition onto ships near the Faroe and Shetland Islands, 700 to 1100 km away from Hekla, demonstrate that even moderate-sized Hekla eruptions can affect very large parts of European air-space.

  10. Geochemical signatures of tephras from Quaternary Antarctic Peninsula volcanoes

    OpenAIRE

    Kraus,Stefan; Kurbatov,Andrei; Yates,Martin

    2013-01-01

    In the northern Antarctic Peninsula area, at least 12 Late Plelstocene-Holocene volcanic centers could be potential sources of tephra layers in the region. We present unique geochemical fingerprints for ten of these volcanoes using major, trace, rare earth element, and isotope data from 95 samples of tephra and other eruption products. The volcanoes have predominantly basaltic and basaltic andesitic compositions. The Nb/Y ratio proves useful to distinguish between volcanic centers located on ...

  11. Revised tephra volumes for Cascade Range volcanoes

    Science.gov (United States)

    Nathenson, Manuel

    2017-01-01

    Isopach maps from tephra eruptions from Mount St. Helens were reported in Carey et al. (1995) and for tephra eruptions from Glacier Peak in Gardner et al. (1998). For exponential thinning, the isopach data only define a single slope on a log thickness versus square root of area plot. Carey et al. (1995) proposed a model that was used to estimate a second slope, and volumes were presented in both studies using this model. A study by Sulpizio (2005) for estimating the second slope and square root of area where the lines intersect involves a systematic analysis of many eruptions to provide correlation equations. The purpose of this paper is to recalculate the volumes of Cascades eruptions and compare results from the two methods. In order to gain some perspective on the methods for estimating the second slope, we use data for thickness versus distance beyond the last isopach that are available for some of the larger eruptions in the Cascades. The thickness versus square root of area method is extended to thickness versus distance by developing an approximate relation between the two assuming elliptical isopachs with the source at one of the foci. Based on the comparisons made between the Carey et al. (1995) and Sulpizio (2005) methods, it is felt that the later method provides a better estimate of the second slope. For Mount St. Helens, the estimates of total volume using the Sulpizio (2005) method are generally smaller than those using the Carey et al. (1995) method. For the volume estimates of Carey et al. (1995), the volume of the May 18, 1980, eruption of Mount St. Helens is smaller than six of the eight previous eruptions. With the new volumes using the Sulpizio (2005) method, the 1980 eruption is smaller in volume than the upper end of the range for only three of the layers (Wn, Ye, and Yn) and is the same size as layer We. Thus the 1980 eruption becomes representative of the mid-range of volumes rather than being in the lower range.

  12. Assessing the long-term probabilistic volcanic hazard for tephra fallout in Reykjavik, Iceland: a preliminary multi-source analysis

    Science.gov (United States)

    Tonini, Roberto; Barsotti, Sara; Sandri, Laura; Tumi Guðmundsson, Magnús

    2015-04-01

    Icelandic volcanism is largely dominated by basaltic magma. Nevertheless the presence of glaciers over many Icelandic volcanic systems results in frequent phreatomagmatic eruptions and associated tephra production, making explosive eruptions the most common type of volcanic activity. Jökulhlaups are commonly considered as major volcanic hazard in Iceland for their high frequency and potentially very devastating local impact. Tephra fallout is also frequent and can impact larger areas. It is driven by the wind direction that can change with both altitude and season, making impossible to predict a priori where the tephra will be deposited during the next eruptions. Most of the volcanic activity in Iceland occurs in the central eastern part, over 100 km to the east of the main population centre around the capital Reykjavík. Therefore, the hazard from tephra fallout in Reykjavík is expected to be smaller than for communities settled near the main volcanic systems. However, within the framework of quantitative hazard and risk analyses, less frequent and/or less intense phenomena should not be neglected, since their risk evaluation depends on the effects suffered by the selected target. This is particularly true if the target is highly vulnerable, as large urban areas or important infrastructures. In this work we present the preliminary analysis aiming to perform a Probabilistic Volcanic Hazard Assessment (PVHA) for tephra fallout focused on the target area which includes the municipality of Reykjavík and the Keflavík international airport. This approach reverts the more common perspective where the hazard analysis is focused on the source (the volcanic system) and it follows a multi-source approach: indeed, the idea is to quantify, homogeneously, the hazard due to the main hazardous volcanoes that could pose a tephra fallout threat for the municipality of Reykjavík and the Keflavík airport. PVHA for each volcanic system is calculated independently and the results

  13. Tools and techniques for developing tephra stratigraphies in lake cores: A case study from the basaltic Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Hopkins, Jenni L.; Millet, Marc-Alban; Timm, Christian; Wilson, Colin J. N.; Leonard, Graham S.; Palin, J. Michael; Neil, Helen

    2015-09-01

    Probabilistic hazard forecasting for a volcanic region relies on understanding and reconstructing the eruptive record (derived potentially from proximal as well as distal volcanoes). Tephrostratigraphy is commonly used as a reconstructive tool by cross-correlating tephra deposits to create a stratigraphic framework that can be used to assess magnitude-frequency relationships for eruptive histories. When applied to widespread rhyolitic deposits, tephra identifications and correlations have been successful; however, the identification and correlation of basaltic tephras are more problematic. Here, using tephras in drill cores from six maars in the Auckland Volcanic Field (AVF), New Zealand, we show how X-ray density scanning coupled with magnetic susceptibility analysis can be used to accurately and reliably identify basaltic glass shard-bearing horizons in lacustrine sediments and which, when combined with the major and trace element signatures of the tephras, can be used to distinguish primary from reworked layers. After reliably identifying primary vs. reworked basaltic horizons within the cores, we detail an improved method for cross-core correlation based on stratigraphy and geochemical fingerprinting. We present major and trace element data for individual glass shards from 57 separate basaltic horizons identified within the cores. Our results suggest that in cases where major element compositions (SiO2, CaO, Al2O3, FeO, MgO) do not provide unambiguous correlations, trace elements (e.g. La, Gd, Yb, Zr, Nb, Nd) and trace element ratios (e.g. [La/Yb]N, [Gd/Yb]N, [Zr/Yb]N) are successful in improving the compositional distinction between the AVF basaltic tephra horizons, thereby allowing an improved eruptive history of the AVF to be reconstructed.

  14. The role of tephra studies in African paleoanthropology as exemplified by the Sidi Hakoma Tuff

    Science.gov (United States)

    WoldeGabriel, Giday; Endale, Tamrat; White, Tim D.; Thouveny, Nicolas; Hart, William K.; Renne, Paul R.; Asfaw, Berhane

    2013-01-01

    Beginning in the 1960s, geological and paleoanthropological exploration of the Ethiopian rift system's basins have led to the discovery and assembly of the most comprehensive record of human biological and technological change during the last 6 million years. The hominid fossils, including partial skeletons, were primarily discovered in the Afar Rift, the Main Ethiopian Rift, and in the Omo Basin of the broadly rifted zone of SW Ethiopia. The paleoanthropological research areas within the SW Afar Rift that have yielded many diverse hominid species and the oldest stone tools are, from north to south, Woranso-Mille (aff. Ardipithecus and Au. afarensis), Hadar (Au. afarensis, Homo sp.), Dikika (Au. afarensis), Gona (Ar. kadabba, Ar. ramidus, H. erectus, and oldest stone tools), Middle Awash (Ar. kadabba, Ar. ramidus, Au. anamensis, Au. afarensis, Au. garhi, H. erectus, H. rhodesiensis, H. sapiens idaltu, and the oldest paleo-butchery locality), and Galili (Au. afarensis). Additional hominid remains were discovered at Melka Kunture on the banks of the Awash River near its source along the western margin of the central part of the Main Ethiopian Rift (H. erectus), at Konso (H. erectus and A. boisei), and at the southern end of the MER, and in the Omo Basin (Au. anamensis, Au. afarensis, Au. aethiopicus, Au. boisei, H. habilis, and H. erectus). Distal and sometimes proximal tephra units interbedded within fossilifeous sedimentary deposits have become key elements in this work by providing chronological and correlative control and depositional contexts. Several regional tephra markers have been identified within the northern half of the eastern African rift valley in Ethiopia and Kenya, and in marine sediments of the Gulf of Aden Rift and the NW Indian Ocean. Out of the many regional tephra stratigraphic markers that range in age from the early Pliocene (3.97 Ma) to the late Pleistocene (0.16 Ma), the Sidi Hakoma Tuff (SHT) has been more widely identified and thoroughly

  15. Correlation of Plio Pleistocene Tephra in Ethiopian and Kenyan rift basins: Temporal calibration of geological features and hominid fossil records

    Science.gov (United States)

    WoldeGabriel, Giday; Hart, William K.; Katoh, Shigehiro; Beyene, Yonas; Suwa, Gen

    2005-10-01

    The 200-m-thick fossiliferous Konso Formation and overlying terrace deposits, which crop out at the end of the southern sector of the Main Ethiopian Rift (MER), contain more than 30 distal tephra layers. Local and regional tephra correlations of more than 20 tephra units were established using major and trace element data of discrete and purified bulk glass samples within the Konso study area. Eleven correlative marker tuffs were recognized in stratigraphic sections of both the Konso Formation and the Omo-Turkana Basin sediments in southern Ethiopia and northern Kenya. The Turoha, Hope, Ivory, Bright White, and Boleshe Tuffs in the Konso Formation, and the Upper White Tuff in the overlying terrace deposits are securely correlated with the KBS, Akait, Lokapetamoi, Chari, Lower Nariokotome, and Silbo Tuffs of the Omo-Turkana Basin, using least mobile major elements (CaO, Fe 2O 3*, and TiO 2) and geochronology. Preliminary correlations are also suggested between the Konso Formation distal tephra and proximal units of the Quaternary caldera-forming silicic centers in the central sector of the MER. The strongly peralkaline tuffs of the Konso Formation are compositionally similar to proximal eruptions mostly located along the Quaternary axial rift zone of the southern, central, and northern sectors of the MER. The tephra correlation provides information about the temporal and spatial features of the volcanic and tectonic processes recorded in the evolving basins. Thickness and sedimentation rate were determined for both the Konso Formation and the Omo-Turkana Basin sections, measured between the Turoha (=KBS; 1.91 ± 0.03 Ma) and the Bright White (=Chari; 1.40 ± 0.02 Ma) Tuffs. Although the lithostratigraphic sequence at the Konso study area is younger, sedimentation rate within the Konso Formation was comparable to that of the Koobi Fora Formation, higher in the Nachukui Formation, and lower in the Shungura Formation. Local and regional differences in thickness and

  16. Connecting, synchronising, and dating with tephras : principles and applications of tephrochronology in Quaternary research

    International Nuclear Information System (INIS)

    Lowe, D.J.

    2016-01-01

    Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic or archaeological sequences or events. The method relies firstly and fundamentally on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or 'fingerprinting' tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g. Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e. comparing 'fingerprints' from each layer. Used this way, tephrochronology is an age-equivalent dating method. (author).

  17. Connecting with tephras : principles, functioning, and applications of tephrochronology in Quaternary science

    International Nuclear Information System (INIS)

    Lowe, D.J.

    2013-01-01

    Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic or archaeological sequences or events. The method relies firstly and fundamentally on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or 'fingerprinting' tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g. Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e. comparing 'fingerprints' from each layer. Used this way, tephrochronology is an age-equivalent dating method. (author). 150 refs., 13 figs., 5 tabs.

  18. Connecting with tephras: principles, functioning, and applications of tephrochronology in Quaternary science

    International Nuclear Information System (INIS)

    Lowe, D.J.

    2014-01-01

    Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic or archaeological sequences or events. The method relies firstly and fundamentally on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or 'fingerprinting' tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g. Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e. comparing 'fingerprints' from each layer. Used this way, tephrochronology is an age-equivalent dating method. (author)

  19. Connecting, synchronising, and dating with tephras : principles and applications of tephrochronology in Quaternary research

    International Nuclear Information System (INIS)

    Lowe, D.J.

    2017-01-01

    Tephrochronology is a unique method for linking and dating geological, palaeoecological, palaeoclimatic or archaeological sequences or events. The method relies firstly and fundamentally on stratigraphy and the law of superposition, which apply in any study that connects or correlates deposits from one place to another. Secondly, it relies on characterising and hence identifying or 'fingerprinting' tephra layers using either physical properties evident in the field or those obtained from laboratory analysis, including mineralogical examination by optical microscopy or geochemical analysis of glass shards or crystals (e.g. Fe-Ti oxides, ferromagnesian minerals) using the electron microprobe and other tools. Thirdly, the method is enhanced when a numerical age is obtained for a tephra layer by (1) radiometric methods such as radiocarbon, fission-track, U-series, or Ar/Ar dating, (2) incremental dating methods including dendrochronology or varved sediments or layering in ice cores, or (3) age-equivalent methods such as palaeomagnetism or correlation with marine oxygen isotope stages or palynostratigraphy. Once known, that age can be transferred from one site to the next using stratigraphic methods and by matching compositional characteristics, i.e. comparing 'fingerprints' from each layer. Used this way, tephrochronology is an age-equivalent dating method. (author).

  20. Tephra stratification of volcanic ash soils in Nothern Ecuador

    NARCIS (Netherlands)

    Tonneijck, F.H.; Hageman, J.A.; Sevink, J.; Verstraten, J.M.

    2008-01-01

    We combined proxies traditionally used in stratigraphic research (mineral assemblages, grain size distribution, and element ratios) with soil organic carbon contents and radiocarbon dating both at a high vertical resolution, to unravel the tephra stratigraphy in volcanic ash soils. Our results show

  1. Flood, Seismic or Volcanic Deposits? New Insights from X-Ray Computed Tomography

    Science.gov (United States)

    Van Daele, M. E.; Moernaut, J.; Vermassen, F.; Llurba, M.; Praet, N.; Strupler, M. M.; Anselmetti, F.; Cnudde, V.; Haeussler, P. J.; Pino, M.; Urrutia, R.; De Batist, M. A. O.

    2014-12-01

    Event deposits, such as e.g. turbidites incorporated in marine or lacustrine sediment sequences, may be caused by a wide range of possible triggering processes: failure of underwater slopes - either spontaneous or in response to earthquake shaking, hyperpycnal flows and floods, volcanic processes, etc. Determining the exact triggering process remains, however, a major challenge. Especially when studying the event deposits on sediment cores, which typically have diameters of only a few cm, only a small spatial window is available to analyze diagnostic textural and facies characteristics. We have performed X-ray CT scans on sediment cores from Chilean, Alaskan and Swiss lakes. Even when using relatively low-resolution CT scans (0.6 mm voxel size), many sedimentary structures and fabrics that are not visible by eye, are revealed. For example, the CT scans allow to distinguish tephra layers that are deposited by fall-out, from those that reached the basin by river transport or mud flows and from tephra layers that have been reworked and re-deposited by turbidity currents. The 3D data generated by the CT scans also allow to examine relative orientations of sedimentary structures (e.g. convolute lamination) and fabrics (e.g. imbricated mud clasts), which can be used to reconstruct flow directions. Such relative flow directions allow to determine whether a deposit (e.g. a turbidite) had one or several source areas, the latter being typical for seismically triggered turbidites. When the sediment core can be oriented (e.g. using geomagnetic properties), absolute flow directions can be reconstructed. X-ray CT scanning, at different resolution, is thus becoming an increasingly important tool for discriminating the exact origin of EDs, as it can help determining whether e.g. an ash layer was deposited as fall out from an ash cloud or fluvially washed into the lake, or whether a turbidite was triggered by an earthquake or a flood.

  2. A tephra lattice for Greenland and a reconstruction of volcanic events spanning 25-45 ka b2k

    Science.gov (United States)

    Bourne, A. J.; Cook, E.; Abbott, P. M.; Seierstad, I. K.; Steffensen, J. P.; Svensson, A.; Fischer, H.; Schüpbach, S.; Davies, S. M.

    2015-06-01

    Tephra layers preserved within the Greenland ice-cores are crucial for the independent synchronisation of these high-resolution records to other palaeoclimatic archives. Here we present a new and detailed tephrochronological framework for the time period 25,000-45,000 a b2k that brings together results from 4 deep Greenland ice-cores. In total, 99 tephra deposits, the majority of which are preserved as cryptotephra, are described from the NGRIP, NEEM, GRIP and DYE-3 records. The major element signatures of single glass shards within these deposits indicate that 93 are basaltic in composition all originating from Iceland. Specifically, 43 originate from Grimsvötn, 20 are thought to be sourced from the Katla volcanic system and 17 show affinity to the Kverkfjöll system. Robust geochemical characterisations, independent ages derived from the GICC05 ice-core chronology, and the stratigraphic positions of these deposits relative to the Dansgaard-Oeschger climate events represent a key framework that provides new information on the frequency and nature of volcanic events in the North Atlantic region between GS-3 and GI-12. Of particular importance are 19 tephra deposits that lie on the rapid climatic transitions that punctuate the last glacial period. This framework of well-constrained, time-synchronous tie-lines represents an important step towards the independent synchronisation of marine, terrestrial and ice-core records from the North Atlantic region, in order to assess the phasing of rapid climatic changes during the last glacial period.

  3. Trace Element Geochemistry of Basaltic Tephra in Maar Cores; Implications for Centre Correlation, Field Evolution, and Mantle Source Characteristics of the Auckland Volcanic Field, New Zealand

    Science.gov (United States)

    Hopkins, J. L.; Leonard, G.; Timm, C.; Wilson, C. J. N.; Neil, H.; Millet, M. A.

    2014-12-01

    Establishing volcanic hazard and risk management strategies hinges on a detailed understanding of the type, timing and tephra dispersal of past eruptions. In order to unravel the pyroclastic eruption history of a volcanic field, genetic links between the deposits and eruption source centre need to be established. The Auckland Volcanic Field (AVF; New Zealand) has been active for ca. 200 kyr and comprises ca. 53 individual centres covering an area of ca. 360km2. These centres show a range of sizes and eruptive styles from maar craters and tuff rings, to scoria cones and lava flows consistent with both phreatomagmatic and magmatic eruptions. Superimposition of the metropolitan area of Auckland (ca. 1.4 million inhabitants) on the volcanic field makes it critically important to assess the characteristics of the volcanic activity, on which to base assessment and management of the consequent hazards. Here we present a geochemical approach for correlating tephra deposits to their source centres. To acquire the most complete stratigraphic record of pyroclastic events, maar crater cores from different locations, covering various depths and thus ages across the field were selected. Magnetic susceptibility and x-ray density scanning of the cores was used to identify the basaltic tephra horizons, which were sampled and in-situ analysis of individual shards undertaken for major and trace elements using EPMA and LA-ICP-MS techniques, respectively. Our results show that tephra shard trace element ratios are comparable and complementary to the AVF whole rock database. The use of specific trace element ratios (e.g. Gd/Yb vs. Zr/Yb) allows us to fingerprint and cross correlate tephra horizons between cores and, when coupled with newly acquired 40Ar-39Ar age dating and eruption size estimates, correlate horizons to their source centres. This integrated style of study can provide valuable information to help volcanic hazard management and forecasting, and mitigation of related risks.

  4. Changes in Mass Flux of Tephra from the Lava Lake in Overlook Crater, Kīlauea Volcano, Hawai`i

    Science.gov (United States)

    Swanson, D. A.; Orr, T. R.; Patrick, M. R.

    2016-12-01

    The mass flux of tephra (mostly Pele's hair and tears, hollow spherules, and lithic clasts) from the lava lake in Overlook crater varies on short (seconds-minutes), intermediate (hours-days), and long (months) time scales. The tephra is collected almost daily from a network of 10 buckets within 400 m of, and 100-150 m above, the lava lake; bucket locations have not changed during the eruption. A mass accumulation rate (AR) is calculated for the network; since April 2008, the AR averages 0.17 g/m2/h ( 5×10-8 kg/m2/s). The tephra forms during almost constant spattering at the SE sink (the main downwelling site) and ephemeral sites along the crater wall, as well as from sporadic, rockfall-induced violent outgassing that can eject decimeter-size spatter clots onto the crater rim; the average AR excludes these violent events. The rockfalls, and nearly constant raveling from the crater wall, introduce lithic clasts into the tephra. The lithic content of the tephra has decreased with time, reflecting both greater wall stability and higher lake level, and was usually 7 m/s). At intermediate and long time scales, juvenile AR shows no correlation with measured SO2 output and only weak or no correlation with wind speed, but it often tracks the elevation of the lake surface—higher when lava is nearer the buckets. For example, both lava level and juvenile AR were unusually high in January-July 2016. Before 2016, however, 7-9 periods of heightened juvenile production (see figure below), each lasting several months, show no correlation with other monitored parameters—lake level, SO2, wind speed and direction, or downwelling location. Often AR gradually increased to a peak before falling off, sometimes to nearly zero. We speculate that such long-term variations result from changes in magma supply rate, gas concentration, or rise frequency of decoupled gas slugs. These changes may be too small or slow to detect by current geodetic and gas monitoring. They suggest a slowly

  5. The sky is falling III: The effect of deposition from static solid rocket motor tests on juvenile crops.

    Science.gov (United States)

    Doucette, William J; Curry, Eric; McNeill, Laurie S; Heavilin, Justin

    2017-12-01

    A mixture of combustion products (mainly hydrogen chloride, aluminum oxide, and water) and entrained soil, referred to as Test Fire Soil (TFS), can be deposited on crops during static solid rocket motor tests. The impact of a reported worst-case event was previously evaluated by exposing corn and alfalfa to 3200-gTFS/m 2 at 54days after emergence. Exposures via soil and leaves were evaluated separately. Reduced growth (soil exposure) and leaf "scorch" (leaf exposure) were attributed mainly to the high chloride concentrations in the TFS (56,000mg/kg). A follow-up study was conducted to evaluate the effect of a typical deposition event (70-gTFS/m 2 , estimated by radar during several tests) and exposure (soil and leaves simultaneously) on juvenile corn, alfalfa, and winter wheat. Younger crops were used to examine potential age sensitivity differences. Impact was evaluated by comparing the growth, elemental composition, and leaf chlorophyll content of treated and untreated plants. The relationship between deposition exposure and response was also addressed. Growth of corn, alfalfa, and winter wheat exposed to a typical TFS loading was not impacted, although slightly elevated concentrations of aluminum and iron were found in the leaves. At the highest loadings used for the exposure-response experiment, concentrations of chloride and calcium were higher in TFS-exposed corn leaves than in the untreated leaves. Overall results indicate that exposure to a typical deposition event does not adversely impact juvenile crops and that younger plants may be less vulnerable to TFS. However, higher TFS loadings can cause leaf scorch and increase the leaf concentrations of some elements. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. The ELSA tephra stack: Volcanic activity in the Eifel during the last 500,000 years

    Science.gov (United States)

    Förster, Michael W.; Sirocko, Frank

    2016-07-01

    Tephra layers of individual volcanic eruptions are traced in several cores from Eifel maar lakes, drilled between 1998 and 2014 by the Eifel Laminated Sediment Archive (ELSA). All sediment cores are dated by 14C and tuned to the Greenland interstadial succession. Tephra layers were characterized by the petrographic composition of basement rock fragments, glass shards and characteristic volcanic minerals. 10 marker tephra, including the well-established Laacher See Tephra and Dümpelmaar Tephra can be identified in the cores spanning the last glacial cycle. Older cores down to the beginning of the Elsterian, show numerous tephra sourced from Strombolian and phreatomagmatic eruptions, including the 40Ar/39Ar dated differentiated tephra from Glees and Hüttenberg. In total, at least 91 individual tephra can be identified since the onset of the Eifel volcanic activity at about 500,000 b2k, which marks the end of the ELSA tephra stack with 35 Strombolian, 48 phreatomagmatic and 8 tephra layers of evolved magma composition. Many eruptions cluster near timings of the global climate transitions at 140,000, 110,000 and 60,000 b2k. In total, the eruptions show a pattern, which resembles timing of phases of global sea level and continental ice sheet changes, indicating a relation between endogenic and exogenic processes.

  7. High-MgO Vitric Ash in Upper Kulanaokuaiki Tephra, Kilauea Volcano, Hawai`i: A Preliminary Description

    Science.gov (United States)

    Rose, T. R.; Fiske, R. S.; Swanson, D.

    2011-12-01

    Small, well-formed Pele's tears containing anomalously high values of MgO were recently discovered in outcrops of the upper Kulanaokuaiki Tephra at and near the base of Uwekahuna Bluff, the western wall of Kilauea Caldera. Electron microprobe analyses of more than 60 high-MgO tears, which are 1-3 mm in diameter, show that most contain 11 to 12 wt. % MgO with a few approaching 13 % MgO. Separate microprobe analyses for sulfur and chlorine of 20 grains revealed no appreciable amounts of either, indicating the magma was largely degassed. Polished-section studies employing an analytical scanning electron microscope show most tears are composed of pure microvesicular glass with scattered skeletal olivine crystals and rare chromite. The abundance of skeletal olivine appears to increase with decreasing MgO content of the glass. These tears contain among the highest known MgO values of any material erupted subaerially from Kilauea. The high-MgO tears occur in a 1-6 cm thick layer of medium-coarse lithic-crystal-vitric ash. The top of this layer consists of 2-3 mm of very fine lithic-crystal ash. The lithics and many of the olivine crystals in this layer are highly oxidized. This deposit is at the top of a sequence of several lithic beds that are interspersed with thinner vitric units totaling about 75 cm in thickness. It is overlain by 9-13 cm of medium pumice lapilli and coarse vitric ash at the top of the "Bluff base" and "mid-Bluff" tephra sections described by Fiske et al. (2009). This high-MgO glass layer has been found thus far in only one other locality, a 2 m-deep soils study pit within Kipuka Puaulu, 3.5 km northwest of the caldera. Based upon stratigraphic relationships and preliminary microprobe data, a few other likely exposures of the high-MgO deposit have been identified north and west of the caldera. The high-MgO vitric ash in the upper Kulanaokuaiki Tephra has a primitive composition that suggests little if any shallow level storage of magma. Instead, the

  8. Hazard assessment of long-range tephra dispersal for a Plinian eruptive scenario at Popocatépetl volcano (Mexico). Inplications on civil aviation

    Science.gov (United States)

    Bonasia, R.; Scaini, C.; Capra, L.; Nathenson, M.; Siebe, C.; Arana-Salinas, L.; Folch, A.

    2013-12-01

    Popocatépetl is one of the most active volcanoes in Mexico threatening a densely populated area that includes Mexico City with more than 20 million inhabitants. The destructive potential of this volcano is demonstrated by its Late Pleistocene-Holocene eruptive activity, which has been characterized by recurrent Plinian eruptions of large magnitude. The current volcanic hazards map, reconstructed after the crisis occurred in 1994, considers the potential occurrence of different volcanic phenomena, including pyroclastic density currents and lahars. However, no quantitative assessment of the tephra dispersal hazard, especially related to atmospheric dispersal, has been performed. Given the high number of important airports in the surroundings of Popocatépetl volcano and considering the potential threat posed to civil aviation in Mexico and adjacent regions in case of a Plinian eruption, a hazard assessment for tephra dispersal is strongly required. In this work we present the first probabilistic tephra dispersal hazard assessment for Popocatépetl volcano. We compute probabilistic hazard maps for critical thresholds of airborne ash concentrations at different flight levels. Tephra dispersal modelling is performed using the FALL3D numerical model. Probabilistic hazard maps are built for a Plinian eruptive scenario defined on the basis of geological field data for the 'Ochre Pumice' Plinian eruption (4965 14C yrBP). FALL3D model input eruptive parameters are constrained through an inversion method carried out with the semi-analytical HAZMAP model and are varied sampling them on the base of a Probability Density Function. We analyze the influence of seasonal variations on ash dispersal and estimate the average persistence of critical ash concentrations at relevant locations and airports. This study assesses the impact that a Plinian eruption similar to the Ochre Pumice eruption would have on the main airports of Mexico and adjacent areas. The hazard maps presented here

  9. TRACEing Last Glacial Period (25-80 ka b2k) tephra horizons within North Atlantic marine cores and exploring links to the Greenland ice-cores

    Science.gov (United States)

    Abbott, P. M.; Davies, S. M.; Griggs, A. J.; Bourne, A. J.; Cook, E.; Pearce, N. J. G.; Austin, W. E. N.; Chapman, M.; Hall, I. R.; Purcell, C. S.; Scourse, J. D.; Rasmussen, T. L.

    2015-12-01

    Tephrochronology is a powerful technique for the correlation and synchronisation of disparate palaeoclimatic records from different depositional environments and has considerable potential for testing climatic phasing. For example, the relative timing of atmospheric and marine changes caused by the abrupt climatic events that punctuated the last glacial period within the North Atlantic region. Here we report on efforts to establish a framework of tephra horizons within North Atlantic marine sequences that can correlate these records and if traced in the Greenland ice-cores can act as isochronous tie-lines. Investigations have been conducted on a network of marine cores from a number of sites across the North Atlantic. Tephra horizons have been identified using cryptotephra extraction techniques more commonly applied to the study of terrestrial sequences. There are two main challenges with assessing cryptotephras in the glacial North Atlantic; i) determining the transportation processes and ii) assessing the influence of secondary reworking processes and the stratigraphic integrity of the isochrons. These processes and their influence are investigated for each cryptotephra using shard size variations, major element heterogeneity and co-variance of IRD input for some cores. Numerous Icelandic cryptophras have been successfully identified in the marine records and we will discuss the integration of a number of these with an isochronous nature into a marine tephra framework and how potential correlations to the Greenland ice-core tephra framework are determined. Spatial patterns in the nature of tephra records that are emerging from the core network will be highlighted to outline some of the key areas that could be explored in the future. In addition, the synchronisation of multiple North Atlantic records to the Greenland ice-cores using the North Atlantic Ash Zone II to test the synchroneity of an abrupt cooling in the North Atlantic will be discussed.

  10. Volcanic Cyclicities in the Pacific Northwest: Insights from the Marine Tephra Record from IODP Expedition 350, Izu Bonin Arc

    Science.gov (United States)

    Straub, S. M.; Schindlbeck, J. C.; Jegen, M. D.; Corry-Saavedra, K.; Murayama, M.; Woodhead, J. D.; Kutterolf, S.; Vautravers, M. J.; Wang, K. L.

    2016-12-01

    While the influences of orbital cycles on the ocean-atmosphere system are well documented, it remains largely unknown whether Earth's interior processes are similarly connected to orbital cycles. Recent studies of cyclic deposition in ash fallout from arc volcanism suggest that global climate changes in the form of variable glacial and water load are inversely related to magma production and/or volcanic eruption rate. However, a rigorous test of this hypotheses requires a temporally precise record of past volcanism which spans multiple glacial cycles at high resolution. The marine ash record of explosive volcanism provides such records readily. Here we undertake a detailed chemical study of discrete and disperse tephra deposits in cores from IODP Holes U1437B and U1436A drilled near the Izu Bonin arc in the northwestern Pacific. These locations combine a high background sedimentation rate (>10 m/Ma) of biogenic carbonate and Asian-derived dust with frequent emplacement of tephra fallout from the nearby Izu Bonin and Japan arcs. δ18O analyses record thirteen climatic cycles in the carbonate mud of the uppermost 120 m of Hole U1437B and eleven cycles in the uppermost 70 m of Hole U1436C. Strikingly, the distribution of 134 primary ash layers in Hole U1437B seems to be synchronous with glacial cycles, with a distinct increase in eruption occurrences at either the transitions of glacial/interglacial or at the early interglacials. This is confirmed by first results of a frequency analysis of the ash-time series that indicate a dominance of a 100 ka cycle. The question, which remains to be answered, is whether deglaciation drives volcanism or volcanism drives deglaciation? We also investigate the distribution of `dispersed ash' in this sequence, which is not visible to the naked eye but is volumetrically significant and thus also critical in testing time-cause relationships between arc volcanism and glacial cycles. Major questions we address are: 1) do we see the same

  11. Total grain-size distribution of four subplinian-Plinian tephras from Hekla volcano, Iceland: Implications for sedimentation dynamics and eruption source parameters

    Science.gov (United States)

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

    2018-05-01

    The size distribution of the population of particles injected into the atmosphere during a volcanic explosive eruption, i.e., the total grain-size distribution (TGSD), can provide important insights into fragmentation efficiency and is a fundamental source parameter for models of tephra dispersal and sedimentation. Recent volcanic crisis (e.g. Eyjafjallajökull 2010, Iceland and Córdon Caulle 2011, Chile) and the ensuing economic losses, highlighted the need for a better constraint of eruption source parameters to be used in real-time forecasting of ash dispersal (e.g., mass eruption rate, plume height, particle features), with a special focus on the scarcity of published TGSD in the scientific literature. Here we present TGSD data associated with Hekla volcano, which has been very active in the last few thousands of years and is located on critical aviation routes. In particular, we have reconstructed the TGSD of the initial subplinian-Plinian phases of four historical eruptions, covering a range of magma composition (andesite to rhyolite), eruption intensity (VEI 4 to 5), and erupted volume (0.2 to 1 km3). All four eruptions have bimodal TGSDs with mass fraction of fine ash (primary fragmentation. Due to differences in plume height, this contrast is not seen in samples from individual sites, especially in the near field, where lapilli have a wider spatial coverage in the Plinian deposits. The distribution of pyroclast sizes in Plinian versus subplinian falls reflects competing influences of more efficient fragmentation (e.g., producing larger amounts of fine ash) versus more efficient particle transport related to higher and more vigorous plumes, displacing relatively coarse lapilli farther down the dispersal axis.

  12. A simple semi-empirical approach to model thickness of ash-deposits for different eruption scenarios

    Directory of Open Access Journals (Sweden)

    A. O. González-Mellado

    2010-11-01

    Full Text Available The impact of ash-fall on people, buildings, crops, water resources, and infrastructure depends on several factors such as the thickness of the deposits, grain size distribution and others. Preparedness against tephra falls over large regions around an active volcano requires an understanding of all processes controlling those factors, and a working model capable of predicting at least some of them. However, the complexity of tephra dispersion and sedimentation makes the search of an integral solution an almost unapproachable problem in the absence of highly efficient computing facilities due to the large number of equations and unknown parameters that control the process. An alternative attempt is made here to address the problem of modeling the thickness of ash deposits as a primary impact factor that can be easily communicated to the public and decision-makers. We develop a semi-empirical inversion model to estimate the thickness of non-compacted deposits produced by an explosive eruption around a volcano in the distance range 4–150 km from the eruptive source.

    The model was elaborated from the analysis of the geometric distribution of deposit thickness of 14 world-wide well-documented eruptions. The model was initially developed to depict deposits of potential eruptions of Popocatépetl and Colima volcanoes in México, but it can be applied to any volcano. It has been designed to provide planners and Civil Protection authorities of an accurate perception of the ash-fall deposit thickness that may be expected for different eruption scenarios. The model needs to be fed with a few easy-to-obtain parameters, namely, height of the eruptive column, duration of the explosive phase, and wind speed and direction, and its simplicity allows it to run in any platform, including a personal computers and even a notebook. The results may be represented as tables, two dimensional thickness-distance plots, or isopach maps using any available

  13. The 2008 phreatomagmatic eruption of Okmok volcano, Aleutian Islands, Alaska: Chronology, deposits, and landform changes

    Science.gov (United States)

    Jessica Larsen,; Neal, Christina; Schaefer, Janet R.; Kaufman, Max; Lu, Zhong

    2015-01-01

    Okmok volcano, Aleutian Islands, Alaska, explosively erupted over a five-week period between July 12 and August 23, 2008. The eruption was predominantly phreatomagmatic, producing fine-grained tephra that covered most of northeastern Umnak Island. The eruption had a maximum Volcanic Explosivity Index (VEI) of 4, with eruption column heights up to 16 km during the opening phase. Several craters and a master tuff cone formed in the caldera as a result of phreatomagmatic explosions and accumulated tephra-fall and surge deposits. Ascending magma continuously interacted with an extensive shallow groundwater table in the caldera, resulting in the phreatomagmatic character of the eruption. Syneruptive explosion and collapse processes enlarged a pre-existing lake, created a second, entirely new lake, and formed new, deep craters. A field of ephemeral collapse pits and collapse escarpments formed where rapid groundwater withdrawal removed material from beneath capping lava flows. This was the first significant phreatomagmatic event in the U.S. since the Ukinrek Maars eruption in 1977.

  14. Probabilistic short-term volcanic hazard in phases of unrest: A case study for tephra fallout

    Science.gov (United States)

    Selva, Jacopo; Costa, Antonio; Sandri, Laura; Macedonio, Giovanni; Marzocchi, Warner

    2014-12-01

    During volcanic crises, volcanologists estimate the impact of possible imminent eruptions usually through deterministic modeling of the effects of one or a few preestablished scenarios. Despite such an approach may bring an important information to the decision makers, the sole use of deterministic scenarios does not allow scientists to properly take into consideration all uncertainties, and it cannot be used to assess quantitatively the risk because the latter unavoidably requires a probabilistic approach. We present a model based on the concept of Bayesian event tree (hereinafter named BET_VH_ST, standing for Bayesian event tree for short-term volcanic hazard), for short-term near-real-time probabilistic volcanic hazard analysis formulated for any potential hazardous phenomenon accompanying an eruption. The specific goal of BET_VH_ST is to produce a quantitative assessment of the probability of exceedance of any potential level of intensity for a given volcanic hazard due to eruptions within restricted time windows (hours to days) in any area surrounding the volcano, accounting for all natural and epistemic uncertainties. BET_VH_ST properly assesses the conditional probability at each level of the event tree accounting for any relevant information derived from the monitoring system, theoretical models, and the past history of the volcano, propagating any relevant epistemic uncertainty underlying these assessments. As an application example of the model, we apply BET_VH_ST to assess short-term volcanic hazard related to tephra loading during Major Emergency Simulation Exercise, a major exercise at Mount Vesuvius that took place from 19 to 23 October 2006, consisting in a blind simulation of Vesuvius reactivation, from the early warning phase up to the final eruption, including the evacuation of a sample of about 2000 people from the area at risk. The results show that BET_VH_ST is able to produce short-term forecasts of the impact of tephra fall during a rapidly

  15. Tephra Sedimentation from a Short-term Wind-affected Volcanic Plume of the 8 October 2016 Aso Nakadake Eruption, Japan

    Science.gov (United States)

    Tsuji, T.; Nishizaka, N.; Onishi, K.

    2017-12-01

    Sedimentation processes during explosive volcanic eruptions can be constrained based on detailed analysis of grain-size variation of tephra deposits. Especially, an accurate description of the amount of fine particles has also significant implications for the assessment of specific tephra hazards. Grain size studies for single short-term eruption has advantage to contribute understanding the sedimentation processes because it is simple compared to long-lasting eruption. The 2016 Aso Nakadake eruption, Japan represents an ideal for the study of short-term eruptions thanks to an accurate investigation. Then, we investigate the grain size variation with distance from the vent and sedimentological features of the deposit to discuss the sedimentation processes of the tephra fragments. The eruption provided pyroclastic flow deposit and fallout tephra which distributed NE to ENE direction from the vent. The deposits between 4 and 20 km from vent consist of fine-coated lapilli to coarse ash, ash pellet and mud droplet in ascending degree. The samples are lapilli-bearing within 20 km from vent and those outside of 20 km mainly consist of ash particles. Detailed analyses of individual samples highlight a rapid decay of maximum and mean grain size for the deposit from proximal to distal. The decay trend of maximum grain-size is approximated by three segments of exponential curves with two breaks-in-slope at 10 and 40 km from vent. Most of the sampled deposits are characterized by bimodal grain-size distributions, with the modes of the coarse subpopulation decreasing with distance from vent and those of the fine subpopulation being mostly stable. The fine subpopulation has been interpreted as being mostly associated with size-selective sedimentation processes (e.g., particle aggregation) confirmed by the existence of fine-coated particles, ash pellet and mud droplet. As the fine-coated particles generally have a higher terminal velocity than the individual constituent

  16. Falling chains

    OpenAIRE

    Wong, Chun Wa; Yasui, Kosuke

    2005-01-01

    The one-dimensional fall of a folded chain with one end suspended from a rigid support and a chain falling from a resting heap on a table is studied. Because their Lagrangians contain no explicit time dependence, the falling chains are conservative systems. Their equations of motion are shown to contain a term that enforces energy conservation when masses are transferred between subchains. We show that Cayley's 1857 energy nonconserving solution for a chain falling from a resting heap is inco...

  17. Geochemical fingerprints by activation analysis of tephra layers in Lake Van sediments, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Landmann, Guenter [Technische Universitaet Darmstadt, Institut fuer Angewandte Geowissenschaften, Schnittspahnstr. 9, 64287 Darmstadt (Germany); Steinhauser, Georg; Sterba, Johannes H. [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria); Kempe, Stephan [Technische Universitaet Darmstadt, Institut fuer Angewandte Geowissenschaften, Schnittspahnstr. 9, 64287 Darmstadt (Germany); Bichler, Max, E-mail: bichler@ati.ac.a [Vienna University of Technology, Atominstitut, Stadionallee 2, 1020 Vienna (Austria)

    2011-07-15

    We discuss geochemical and sedimentological characteristics of 12 tephra layers, intercalated within the finely laminated sediments of Lake Van. Within the about 15 kyr long sediment record studied, volcanic activity concentrated in the periods 2.6-7.2 and 11.9-12.9 kyr B.P. Concentrations of 25 elements provide the geochemical fingerprint of each tephra layer and allow comparison to literature values of potential source volcanoes such as Mts. Nemrut and Suephan. The youngest two tephra layers (and probably also the other three ashes from the 2.6-7.2 kyr B.P. eruptions) originate from the Nemrut volcano. The source of the older tephra (11.9-12.9 kyr B.P.), however, remains unidentified.

  18. Tephra compositions from Late Quaternary volcanoes around the Antarctic Peninsula

    Science.gov (United States)

    Kraus, S.

    2009-12-01

    Crustal extension and rifting processes opened the Bransfield Strait between the South Shetland Islands and the Antarctic Peninsula during the last 4 Ma. Similar processes on the Peninsula's eastern side are responsible for volcanism along Larsen Rift. There are at least 11 volcanic centers with known or suspected Late Pleistocene / Holocene explosive activity (Fig. 1). Fieldwork was carried out on the islands Deception, Penguin, Bridgeman and Paulet, moreover at Melville Peak (King George Is.) and Rezen Peak (Livingston Is.). Of special importance is the second ever reported visit and sampling at Sail Rock, and the work on never before visited outcrops on the northern slopes and at the summit of Cape Purvis volcano (Fig. 1). The new bulk tephra ICP-MS geochemical data provide a reliable framework to distinguish the individual volcanic centers from each other. According to their Mg-number, Melville Peak and Penguin Island represent the most primitive magma source. Nb/Y ratios higher than 0.67 in combination with elevated Th/Yb and Ta/Yb ratios and strongly enriched LREE seem to be diagnostic to distinguish the volcanoes located along the Larsen Rift from those associated with Bransfield Rift. Sr/Y ratios discriminate between the individual Larsen Rift volcanoes, Paulet Island showing considerably higher values than Cape Purvis volcano. Along Bransfield Rift, Bridgeman Island and Melville Peak have notably lower Nb/Y and much higher Th/Nb than Deception Island, Penguin Island and Sail Rock. The latter displays almost double the Th/Yb ratio as compared to Deception Island, and also much higher LREE enrichment but extraordinarily low Ba/Th, discriminating it from Penguin Island. Such extremely low Ba/Th ratios are also typical for Melville Peak, but for none of the other volcanoes. Penguin Island has almost double the Ba/Th and Sr/Y ratios higher than any other investigated volcano. Whereas the volcanoes located in the northern part of Bransfield Strait have Zr

  19. Tephrostratigraphy and geochemical fingerprinting of the Mangaone Subgroup tephra beds, Okataina Volcanic Centre, New Zealand

    International Nuclear Information System (INIS)

    Smith, V.C.; Shane, P.; Smith, I.E.M.

    2002-01-01

    The Mangaone Subgroup is a sequence of 14 plinian tephra beds erupted from the Okataina Volcanic Centre in North Island, New Zealand, that are bracketed between the regional marker beds of Rotoehu Tephra (50-60 ka) and Oruanui Tephra (26 ka). The Mangaone Subgroup tephra beds are separated by thin paleosols in ascending stratigraphic order: unit A, unit B, unit C, Pupuwharau Tephra (new), Pongakawa Tephra (new), Maketu, Te Mahoe, Hauparu, unit G, unit H, Mangaone, Awakeri, Omataroa, and unit L. Geochemical fingerprinting of the glass and phenocryst phases allows clear subdivision of the Mangaone Subgroup into two stratigraphic intervals. Units A-G are rhyodacites and low-SiO 2 rhyolites (71-75.5 wt% SiO 2 glass; 68-71 wt% SiO 2 whole rock), clinopyroxene bearing, with calcic plagioclase (An 40-60 ) and magnesian orthopyroxene (En 60-70 ), and they display high eruption temperatures (870-940 degrees C) and oxygen fugacities (-log f O 2 11.66-10.40). Some of these units are compositionally heterogeneous in the glass phase (SiO 2 range up to 8 wt%), especially unit A, Ngamotu, Te Mahoe, and Hauparu tephra beds. Units A-G can easily be distinguished from other Taupo Volcanic Zone tephra erupted in the last c. 60 000 yr. Units H-L are high SiO 2 rhyolites (76-78 wt% SiO 2 glass; 71.5-75 wt% SiO 2 whole rock), which contain sodic plagioclase (An 30-40 ), low-Mg orthopyroxene (En 50-60 ), and display lower eruption temperatures (755-830 degrees C) and oxygen fugacities (-log f O 2 = 14.7-12.93). Compositional differences in titanomagnetite and ilmenite can also be used to distinguish them from older units. The two compositional groups also form distinct T-f O 2 trends. The shift in chemical affinity follows the large volume Hauparu eruption, and coincides with the likely geographic shift in vent location to the eastern margin of the caldera complex. Tephra beds that both predate and postdate the Mangaone Subgroup also reflect changes in magma type and vent location. The

  20. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes.

    Science.gov (United States)

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-04-12

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for.

  1. The eruption history of the quaternary Eifel volcanic fields: Implications from the ELSA - Tephra - Stack

    Science.gov (United States)

    Förster, Michael; Sirocko, Frank

    2015-04-01

    Numerous tephra layers occur in maar sediments in the quaternary Eifel volcanic fields. The sediments were systematically drilled and cored since 1998 by the Eifel Laminated Sediment Archive project (ELSA) (Sirocko et al. 2013). These maar sediments are laminated and the tephra is easily recognizeable by a coarser grain size. Additionaly, tephra layers appear dark grey to black in color. The ashes were sieved to a fraction of 250 - 100 µm and sorted into grains of: reddish and greyish sandstone, quartz, amphibole, pyroxene, scoria and pumice, sanidine, leucite and biotite. A minimum of 100 grains for each tephra layer were used for a sediment petrographic tephra characterisation (SPTC). The grain counts resemble the vol. -% of each grain species. Three types of tephra could be identified by their distinctive grain pattern: (1) phreatomagmatic tephra, rich in basement rocks like greyish/reddish sandstone and quartz. (2) Strombolian tephra, rich in scoria and mafic minerals like pyroxene. (3) evolved tephra, rich in sanidine and pumice. 16 drill-cores, covering the last 500 000 years have been examined. Younger cores were dated by 14C ages and older cores by optical stimulated luminescence. Independently from this datings, the drill-cores were cross-correlated by pollen and the occurences of specific marker-tephra layers, comprising characteristic grain-types. These marker-tephra layers are especially thick and of evolved composition with a significant abundance of sanidine and pumice. The most prominent tephra layers of this type are the Laacher See tephra, dated to 12 900 b2k by Zolitschka (1998), the 40Ar/39Ar dated tephra layers of Dümpelmaar, Glees and Hüttenberg, dated to 116 000 b2k, 151 000 b2k and 215 000 b2k by van den Bogaard & Schmincke (1990), van den Bogaard et al. (1989). These datings set the time-frame for the eruption-phases of the quaternary Eifel Volcanic Fields. Our study refines these findings and shows that phases of activity are very

  2. Leaching of lava and tephra from the Oldoinyo Lengai volcano (Tanzania): Remobilization of fluorine and other potentially toxic elements into surface waters of the Gregory Rift

    Science.gov (United States)

    Bosshard-Stadlin, Sonja A.; Mattsson, Hannes B.; Stewart, Carol; Reusser, Eric

    2017-02-01

    different F-bearing minerals. In the natrocarbonatites, fluorine exists predominantly in fluorite (CaF2), and in the early tephra as Na-Mg bearing salts such as neighborite (NaMgF3) and sellaite (MgF2). All these three minerals have very low solubility in water (16-130 mg/l). The later nephelinitic tephras contain surface coating of villiaumite (NaF), which is highly soluble (42,200 mg/l) in water and can thus release the fluoride more readily upon contact with water. Although there is still the need for further data and a more precise study on this topic in Tanzania, we can already draw a first conclusion that the intake of water during or directly following the deposition of the tephra is not advisable and should be avoided, whereas the release of fluoride from the lava flow has less influence on the river waters.

  3. Compositional Variations of Paleogene and Neogene Tephra From the Northern Izu-Bonin-Mariana Arc

    Science.gov (United States)

    Tepley, F. J., III; Barth, A. P.; Brandl, P. A.; Hickey-Vargas, R.; Jiang, F.; Kanayama, K.; Kusano, Y.; Li, H.; Marsaglia, K. M.; McCarthy, A.; Meffre, S.; Savov, I. P.; Yogodzinski, G. M.

    2014-12-01

    A primary objective of IODP Expedition 351 was to evaluate arc initiation processes of the Izu-Bonin-Mariana (IBM) volcanic arc and its compositional evolution through time. To this end, a single thick section of sediment overlying oceanic crust was cored in the Amami Sankaku Basin where a complete sediment record of arc inception and evolution is preserved. This sediment record includes ash and pyroclasts, deposited in fore-arc, arc, and back-arc settings, likely associated with both the ~49-25 Ma emergent IBM volcanic arc and the evolving Ryukyu-Kyushu volcanic arc. Our goal was to assess the major element evolution of the nascent and evolving IBM system using the temporally constrained record of the early and developing system. In all, more than 100 ash and tuff layers, and pyroclastic fragments were selected from temporally resolved portions of the core, and from representative fractions of the overall core ("core catcher"). The samples were prepared to determine major and minor element compositions via electron microprobe analyses. This ash and pyroclast record will allow us to 1) resolve the Paleogene evolutionary history of the northern IBM arc in greater detail; 2) determine compositional variations of this portion of the IBM arc through time; 3) compare the acquired data to an extensive whole rock and tephra dataset from other segments of the IBM arc; 4) test hypotheses of northern IBM arc evolution and the involvement of different source reservoirs; and 5) mark important stratigraphic markers associated with the Neogene volcanic history of the adjacent evolving Ryukyu-Kyushu arc.

  4. Electron microprobe analyses of glasses from Kīlauea tephra units, Kīlauea Volcano, Hawaii

    Science.gov (United States)

    Helz, Rosalind L.; Clague, David A.; Mastin, Larry G.; Rose, Timothy R.

    2014-01-01

    This report presents approximately 2,100 glass analyses from three tephra units of Kīlauea Volcano: the Keanakākoʻi Tephra, the Kulanaokuaiki Tephra, and the Pāhala Ash. It also includes some new analyses obtained as part of a re-evaluation of the MgO contents of glasses in two of the three original datasets; this re-evaluation was conducted to improve the consistency of glass MgO contents among the three datasets. The glass data are a principal focus of Helz and others (in press), which will appear in the AGU Monograph Hawaiian Volcanoes—From Source to Surface. The report is intended to support this publication, in addition to making the data available to the scientific community.

  5. Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i

    Science.gov (United States)

    Swanson, Don; Wooten, Kelly M.; Orr, Tim R.

    2009-01-01

    The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations.The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.

  6. Promise and pitfalls for characterizing and correlating the zeolitically altered tephra of the Pleistocene Peninj Group, Tanzania

    Science.gov (United States)

    McHenry, Lindsay J.; Luque, Luis; Gómez, José Ángel; Diez-Martín, Fernando

    2011-05-01

    The Pleistocene Humbu and Moinik formations of the Peninj Group in northern Tanzania preserve an important archaeological and paleontological record, in addition to a record of local volcanism in the form of tephra and lavas. Samples of the major Humbu and Moinik formations' basaltic and trachytic tephra were collected and characterized using phenocryst composition and both primary and authigenic mineral assemblage, since the volcanic glass was completely altered to zeolite. Some tephra are distinguishable solely using phenocrysts, but some are too similar in mineral composition or too poor in phenocrysts to definitively "fingerprint" without glass. Titanomagnetite phenocrysts were mostly altered; characterization was thus limited to feldspar, augite, and hornblende compositions for most tephra. Phenocryst compositions were compared to Olduvai tephra compositions to see if any regional tephra could be identified that could help correlate the sites. Augite or hornblende composition rules out potential correlations of Olduvai Bed I Tuff IF and the Bed II Bird Print Tuff or Tuff IID to otherwise similar Peninj Group tephra. Despite their overlap in age and locations at less than ~ 80 km from the Ngorongoro Volcanic Highlands, Peninj and Olduvai have different tephra records, which limits the possibilities for establishing a regional tephrostratigraphic framework.

  7. Resolving the age of Wilson Creek Formation tephras and the Mono Lake excursion using high-resolution SIMS dating of allanite and zircon rims

    Science.gov (United States)

    Vazquez, J. A.; Lidzbarski, M. I.

    2012-12-01

    Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and interbedded rhyolitic tephras yield discordant 14C and 40Ar/39Ar results due to open-system effects, carbon reservoir uncertainties, as well as abundant xenocrysts entrained during eruption. Ion microprobe (SIMS) 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yields ages that effectively date eruption of key tephra beds and resolve age uncertainties about the Wilson Creek stratigraphy. To date the final several micrometers of crystal growth, individual allanite and zircon crystals were embedded in soft indium to allow sampling of unpolished rims. Isochron ages derived from rims on coexisting allanite and zircon (± glass) from hand-selected pumiceous pyroclasts delimit the timing of Wilson Creek sedimentation between Ashes 7 and 19 (numbering of Lajoie, 1968) to the interval between ca. 27 to ca. 62 ka. The interiors of individual allanite and zircon crystals sectioned in standard SIMS mounts yield model 238U-230Th ages that are mostly hydrologic responses in the Sierra Nevada and Mono Basin to climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation. Moreover, the results demonstrate that high-spatial resolution SIMS dating of accessory mineral rims is an alternative and promising approach for resolving the depositional ages of silicic tephras containing minerals that crystallized over protracted intervals or that are plagued by incorporation of xenocrysts

  8. The sky is falling II: Impact of deposition produced during the static testing of solid rocket motors on corn and alfalfa.

    Science.gov (United States)

    Doucette, William J; Mendenhall, Scout; McNeill, Laurie S; Heavilin, Justin

    2014-06-01

    Tests of horizontally restrained rocket motors at the ATK facility in Promontory, Utah, USA result in the deposition of an estimated 1.5million kg of entrained soil and combustion products (mainly aluminum oxide, gaseous hydrogen chloride and water) on the surrounding area. The deposition is referred to as test fire soil (TFS). Farmers observing TFS deposited on their crops expressed concerns regarding the impact of this material. To address these concerns, we exposed corn and alfalfa to TFS collected during a September 2009 test. The impact was evaluated by comparing the growth and tissue composition of controls relative to the treatments. Exposure to TFS, containing elevated levels of chloride (1000 times) and aluminum (2 times) relative to native soils, affected the germination, growth and tissue concentrations of various elements, depending on the type and level of exposure. Germination was inhibited by high concentrations of TFS in soil, but the impact was reduced if the TFS was pre-leached with water. Biomass production was reduced in the TFS amended soils and corn grown in TFS amended soils did not develop kernels. Chloride concentrations in corn and alfalfa grown in TFS amended soils were two orders of magnitude greater than controls. TFS exposed plants contained higher concentrations of several cations, although the concentrations were well below livestock feed recommendations. Foliar applications of TFS had no impact on biomass, but some differences in the elemental composition of leaves relative to controls were observed. Washing the TFS off the leaves lessened the impact. Results indicate that the TFS deposition could have an effect, depending on the amount and growth stage of the crops, but the impact could be mitigated with rainfall or the application of additional irrigation water. The high level of chloride associated with the TFS is the main cause of the observed impacts. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Diagenesis in tephra-rich sediments from the Lesser Antilles Volcanic Arc: Pore fluid constraints

    Science.gov (United States)

    Murray, Natalie A.; McManus, James; Palmer, Martin R.; Haley, Brian; Manners, Hayley

    2018-05-01

    We present sediment pore fluid and sediment solid phase results obtained during IODP Expedition 340 from seven sites located within the Grenada Basin of the southern Lesser Antilles Volcanic Arc region. These sites are generally characterized as being low in organic carbon content and rich in calcium carbonate and volcanogenic material. In addition to the typical reactions related to organic matter diagenesis, pore fluid chemistry indicates that the diagenetic reactions fall within two broad categories; (1) reactions related to chemical exchange with volcanogenic material and (2) reactions related to carbonate dissolution, precipitation, or recrystallization. For locations dominated by reaction with volcanogenic material, these sites exhibit increases in dissolved Ca with coeval decreases in Mg. We interpret this behavior as being driven by sediment-water exchange reactions from the alteration of volcanic material that is dispersed throughout the sediment package, which likely result in formation of Mg-rich secondary authigenic clays. In contrast to this behavior, sediment sequences that exhibit decreases in Ca, Mg, Mn, and Sr with depth suggest that carbonate precipitation is an active diagenetic process affecting solute distributions. The distributions of pore fluid 87Sr/86Sr reflect these competitive diagenetic reactions between volcanic material and carbonate, which are inferred by the major cation distributions. From one site where we have solid phase 87Sr/86Sr (site U1396), the carbonate fraction is found to be generally consistent with the contemporaneous seawater isotope values. However, the 87Sr/86Sr of the non-carbonate fraction ranges from 0.7074 to 0.7052, and these values likely represent a mixture of local arc volcanic sources and trans-Atlantic eolian sources. Even at this site where there is clear evidence for diagenesis of volcanogenic material, carbonate diagenesis appears to buffer pore fluid 87Sr/86Sr from the larger changes that might be

  10. Students fall for Fall Meeting

    Science.gov (United States)

    Smedley, Kara

    2012-02-01

    From Boston to Beijing, thousands of students traveled to San Francisco for the 2011 AGU Fall Meeting. Of those who participated, 183 students were able to attend thanks to AGU's student travel grant program, which assists students with travel costs and seeks to enrich the meeting through ethnic and gender diversity. Students at Fall Meeting enjoyed a variety of programs and activities designed to help them better network with their peers, learn about new fields, and disseminate their research to the interested public. More than 800 students attended AGU's first annual student mixer, sharing drinks and ideas with fellow student members and future colleagues as well as forging new friendships and intellectual relationships.

  11. Operational short-term Probabilistic Volcanic Hazard Assessment of tephra fallout: an example from the 1982-1984 unrest at Campi Flegrei

    Science.gov (United States)

    Sandri, Laura; Selva, Jacopo; Costa, Antonio; Macedonio, Giovanni; Marzocchi, Warner

    2014-05-01

    Probabilistic Volcanic Hazard Assessment (PVHA) represents the most complete scientific contribution for planning rational strategies aimed at mitigating the risk posed by volcanic activity at different time scales. The definition of the space-time window for PVHA is related to the kind of risk mitigation actions that are under consideration. Short intervals (days to weeks) are important for short-term risk mitigation actions like the evacuation of a volcanic area. During volcanic unrest episodes or eruptions, it is of primary importance to produce short-term tephra fallout forecast, and frequently update it to account for the rapidly evolving situation. This information is obviously crucial for crisis management, since tephra may heavily affect building stability, public health, transportations and evacuation routes (airports, trains, road traffic) and lifelines (electric power supply). In this study, we propose a methodology for the short-term PVHA and its operational implementation, based on the model BET_EF, in which measures from the monitoring system are used to routinely update the forecast of some parameters related to the eruption dynamics, that is, the probabilities of eruption, of every possible vent position and every possible eruption size. Then, considering all possible vent positions and eruptive sizes, tephra dispersal models are coupled with frequently updated meteorological forecasts. Finally, these results are merged through a Bayesian procedure, accounting for epistemic uncertainties at all the considered steps. As case study we retrospectively study some stages of the volcanic unrest that took place in Campi Flegrei (CF) in 1982-1984. In particular, we aim at presenting a practical example of possible operational tephra fall PVHA on a daily basis, in the surroundings of CF at different stages of the 1982-84 unrest. Tephra dispersal is simulated using the analytical HAZMAP code. We consider three possible eruptive sizes (a low, a medium and a

  12. Historical tephra-stratigraphy of the Cosiguina Volcano (Western Nicaragua)

    International Nuclear Information System (INIS)

    Hradecky, Petr; Rapprich, Vladislav

    2008-01-01

    New detailed geological field studies and 14 C dating of the Cosiguina Volcano (westernmost Nicaragua) have allowed to reconstruct a geological map of the volcano and to establish a recent stratigraphy, including three historical eruptions. Five major sequences are represented. I: pyroclastic flows around 1500 AD, II: pyroclastic flows, scoria and pumice flows and surges, III: pyroclastic deposits related to a littoral crater, IV: pyroclastic flows related to 1709 AD eruption, and finally, V: pyroclastic deposits corresponding to the cataclysmic 1835 AD phreatic, phreatomagmatic and subplinian eruption, which seems to be relatively small-scale in comparison with the preceding historical eruptions. The pulsating geochemical character of the pyroclastic rocks in the last five centuries has been documented. The beginning of every eruption is marked by increasing contents of silica and Zr. Based on that, regardless of present-day volcanic repose, the entire Cosiguina Peninsula should be considered as a very hazardous volcanic area. (author)

  13. Thermoluminescence dating of a tephra level from Baume Moula-Guercy (Soyons, Ardeche, France)

    International Nuclear Information System (INIS)

    Sanzelle, S.; Montret, M.; Pilleyre, T.; Miallier, D.; Fain, J.

    1998-01-01

    The Baume Moula-Guercy site (Ardeche, France) is a cave that overhangs the Rhone river valley at a hundred meters height. Since its discovery, it has been assimilated as a shelter with an upper part opened towards the sky. It contains an upper Pleistocene sequence inside which a 2-3 cm localized volcanic layer has been identified. This layer is attributed to an important phreato-magmatic emission from the Vivarais region located at about 50 km SW of the site. The filling of this cave contains neanderthalian remains in a lower level and middle Paleolithic lithic industries in a upper level. Thus, the dating of the tephra level would be of great archaeological importance as it could be used as a chronostratigraphic reference. An estimation of the age obtained by thermoluminescence dating has been requested. This report presents the dating procedure performed on quartz samples extracted from the tephra level and the estimation of the site dosimetry. (J.S.)

  14. Holocene vegetation, environment, and tephra recorded from Lake Pupuke, Auckland, New Zealand

    International Nuclear Information System (INIS)

    Horrocks, M.; Augustinus, P.; Deng, Y.; Shane, P.; Andersson, S.

    2005-01-01

    Lake Pupuke provides a near-complete, high-resolution environmental record of the Holocene from northern New Zealand. Tephra beds constrain the timing of a range of proxy indicators of environmental change, and demonstrate errors in a radiocarbon chronology. Agathis australis forest progressively increases from c. 7000 yr BP and, in conjunction with indicators of reduced biomass productivity, support a model of long-term climate change to drier conditions over the Holocene. However, except for Agathis, conifer-hardwood forest dominated mainly by Dacrydium cupressinum shows little change throughout the pre-human Holocene, suggesting environmental stability. Dramatic vegetation change occurred only within the last millennium as a result of large-scale Polynesian deforestation by fire. This happened a short time before the local eruption of c. 638 cal. yr BP Rangitoto Tephra. The identification of two eruptions of tephra from Rangitoto volcano has implications for future hazard planning in the Auckland region, because the volcanoes were previously considered single event centres. Changes in atmospheric circulation since the Late Glacial, possibly causing lower frequency of distal ashfall in Auckland during the Holocene, complicates the use of long-term records in hazard frequency assessment. (author). 39 refs., 7 figs., 2 tabs

  15. Geochemistry of tephra from Bed I, Olduvai Gorge, Tanzania: Stratigraphic correlations and implications for magmatic evolution

    Science.gov (United States)

    McHenry, L.

    2003-04-01

    At least 10 predominantly trachytic and rhyolitic tuffs are preserved interbedded in volcaniclastic sediments of Plio-Pleistocene Bed I, Olduvai Gorge, Tanzania. Physical correlation of the tuffs is complicated by faulting and variation in preservation and lithofacies. Differences in the degree and type of tephra alteration (clay, zeolitic, none) and preservation of glass shards within the various depositional environments (saline-alkaline lake, lake margin, wetlands, alluvial fan) make correlation by conventional glass chemistry methods impossible. However, variations in overall mineralogy and chemical compositions of co-magmatic phenocrysts (feldspar, augite, titanomagnetite, amphibole) have proven useful to uniquely characterize the tuffs for correlation purposes. Samples of 10 major tuffs in the Olduvai Bed I sequence were collected from various depostional and preservational environments situated up to 15 km apart. Thin sections and mineral separates (10-60 grains of each type of phenocryst/ sample, 2-3 samples/ tuff) were analyzed by electron microprobe for major and minor elements. The lower Bed I tuffs are rhyolitic and easily distinguished from the upper tuffs by the presence of quartz and high-Fe augite. Feldspar composition has been previously found to separate all of the upper tuffs (1B-1F) except the two trachyandesitic tuffs (1D and the "unnamed" tuff between 1E and 1F). Mn and Ti concentrations in the titanomagnetites separate the upper tuffs (MnO%: 1B=1.5-2, 1C=1.3-1.6, 1D=1.1-1.4, 1E=1.5-1.7, unnamed= 0.9-1.2, 1F=1.6-2; TiO2%: 1B, 1E=23-26, 1C=18-22, 1D=25-27, unnamed=20-21, 1F= 12-20). Tuffs 1B, unnamed, and 1F contain abundant amphibole, 1D contains none. Mn and Fe concentrations in the augites also separate the tuffs (MnO%: 1B=1.2-1.5, 1C=0.9-1.2, 1D=0.6-0.9, 1E=0.9-1.1, unnamed=0.5-0.7, 1F=variable; FeO%: 1B=19-21, 1C=15-19, 1D=12-16, 1E=13-16, unnamed=11-14, 1F=variable). Results of these findings provide new widespread markers in the Olduvai

  16. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    Science.gov (United States)

    Pearce, Christof; Varhelyi, Aron; Wastegård, Stefan; Muschitiello, Francesco; Barrientos, Natalia; O'Regan, Matt; Cronin, Thomas M.; Gemery, Laura; Semiletov, Igor; Backman, Jan; Jakobsson, Martin

    2017-04-01

    The caldera-forming eruption of the Aniakchak volcano in the Aleutian Range on the Alaskan Peninsula at 3.6 cal kyr BP was one of the largest Holocene eruptions worldwide. The resulting ash is found as a visible sediment layer in several Alaskan sites and as a cryptotephra on Newfoundland and Greenland. This large geographic distribution, combined with the fact that the eruption is relatively well constrained in time using radiocarbon dating of lake sediments and annual layer counts in ice cores, makes it an excellent stratigraphic marker for dating and correlating mid-late Holocene sediment and paleoclimate records. This study presents the outcome of a targeted search for the Aniakchak tephra in a marine sediment core from the Arctic Ocean, namely Core SWERUS-L2-2-PC1 (2PC), raised from 57 m water depth in Herald Canyon, western Chukchi Sea. High concentrations of tephra shards, with a geochemical signature matching that of Aniakchak ash, were observed across a more than 1.5 m long sediment sequence. Since the primary input of volcanic ash is through atmospheric transport, and assuming that bioturbation can account for mixing up to ca. 10 cm of the marine sediment deposited at the coring site, the broad signal is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points to ice rafting as an important secondary transport mechanism of volcanic ash. Combined with radiocarbon dates on mollusks in the same sediment core, the volcanic marker is used to calculate a marine radiocarbon reservoir age offset ΔR = 477 ± 60 years. This relatively high value may be explained by the major influence of typically carbon-old Pacific waters, and it agrees well with recent estimates of ΔR along the northwest Alaskan coast, possibly

  17. Fall Protection Introduction, #33462

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-23

    The proper use of fall prevention and fall protection controls can reduce the risk of deaths and injuries caused by falls. This course, Fall Protection Introduction (#33462), is designed as an introduction to various types of recognized fall prevention and fall protection systems at Los Alamos National Laboratory (LANL), including guardrail systems, safety net systems, fall restraint systems, and fall arrest systems. Special emphasis is given to the components, inspection, care, and storage of personal fall arrest systems (PFASs). This course also presents controls for falling object hazards and emergency planning considerations for persons who have fallen.

  18. Reconstruction of Ancestral Hydrothermal Systems on Mount Rainier Using Hydrothermally Altered Rocks in Holocene Debris Flows and Tephras

    Science.gov (United States)

    John, D. A.; Breit, G. N.; Sisson, T. W.; Vallance, J. W.; Rye, R. O.

    2005-12-01

    Mount Rainier is the result of episodic stages of edifice growth during periods of high eruptive activity and edifice destruction during periods of relative magmatic quiescence over the past 500 kyr. Edifice destruction occurred both by slow erosion and by catastrophic collapses, some of which were strongly influenced by hydrothermal alteration. Several large-volume Holocene debris-flow deposits contain abundant clasts of hydrothermally altered rocks, most notably the 4-km3 clay-rich Osceola Mudflow which formed by collapse of the northeast side and upper 1000+ m of the edifice about 5600 ya and flowed >120 km downstream into Puget Sound. Mineral assemblages and stable isotope data of hydrothermal alteration products in Holocene debris-flow deposits indicate formation in distinct hydrothermal environments, including magmatic-hydrothermal, steam-heated (including a large fumarolic component), magmatic steam (including a possible fumarolic component), and supergene. The Osceola Mudflow and phreatic components of coeval tephras contain the highest-temperature and inferred most deeply formed alteration minerals; assemblages include magmatic-hydrothermal quartz-alunite, quartz-topaz, quartz-pyrophyllite and quartz-illite (all +pyrite), in addition to steam-heated opal-alunite-kaolinite and abundant smectite-pyrite. In contrast, the Paradise lahar, which formed by a collapse of the surficial upper south side of the edifice, contains only steam-heated assemblages including those formed largely above the water table from condensation of fumarolic vapor (opal-alunite-jarosite). Younger debris-flow deposits on the west side of the volcano (Round Pass lahar and Electron Mudflow) contain only smectite-pyrite alteration, whereas an early 20th century rock avalanche on Tahoma Glacier also contains magmatic-hydrothermal alteration that is exposed in the avalanche headwall of Sunset Amphitheater. Mineralogy and isotopic composition of the alteration phases, geologic and

  19. The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka

    Czech Academy of Sciences Publication Activity Database

    Lowe, J. J.; Ramsey, C. B.; Housley, R. A.; Lane, C. S.; Tomlinson, E. L.; Stringer, C.; Davies, W.; Barton, N.; Pollard, M.; Gamble, C.; Menzies, M.; Rohling, E.; Roberts, A.; Blockley, S.; Cullen, V.; Grant, K.; Lewis, M.; MacLeod, A.; White, D.; Albert, P.; Hardiman, M.; Lee, S.; Oh, A.; Satow, C.; Cross, J. K.; Bramham Law, C.; Todman, A.; Bourne, A.; Matthews, I.; Müller, W.; Smith, V.; Wulf, S.; Anghelinu, M.; Antl-Weiser, W.; Bar-Yosef, O.; Borić, D.; Boscato, P.; Ronchitelli, A.; Chabai, V.; Veselsky, A.; Uthmeier, T.; Farrand, W.; Gjipali, I.; Ruka, R.; Güleç, E.; Karavanić, I.; Karkanas, P.; King, T.; Komšo, D.; Koumouzelis, M.; Kyparissi, N.; Lengyel, G.; Mester, Z.; Neruda, P.; Nigst, P.; Haesaerts, P.; Panagopoulou, E.; Shalamanov-Korobar, L.; Tolevski, I.; Sinitsyn, A.; Sirakov, N.; Guadelli, A.; Guadelli, J.-L.; Ferrier, C.; Škrdla, Petr; Slimak, L.; Soler, N.; Soller, J.; Soressi, M.; Tushabramishvilii, N.; Zilhão, J.; Angelucci, D.; Cullen, V. L.; Lincoln, P.; Staff, R.; Flower, K.; Aouadi-Abdeljaouad, N.; Belhouchet, L.; Barker, G.; Bouzouggar, A.; Van Peer, P.; Kindermann, K.; Gerken, K.; Niemann, H.; Tipping, R.; Saville, A.; Ward, T.; Clausen, I.; Weber, M.-J.; Kaiser, K.; Torksdorf, J. F.; Turner, F.; Veil, S.; Nygaard, N.; Pyne-O'Donnel, S. D. F.; Masojć, M.; Nalepka, D.; Jurochnik, A.; Kabaciński, J.; Antoine, P.; Olive, M.; Christensen, M.; Bodu, P.; Debout, G.; Orliac, M.; De Bie, M.; Van Gils, M.; Paulissen, E.; Brou, L.; Leesch, D.; Hadorn, P.; Thew, N.; Riede, F.; Heinen, M.; Joris, O.; Richter, J.; Knipping, M.; Stika, H.-P.; Friedrich, M.; Conard, N. J.; Malina, M.; Kind, C.-J.; Beutelspacher, T.; Mortensen, M. F.; Burdukiewicz, J. M.; Szynkiewicz, A.; Połtowicz-Bobak, M.; Bobak, D.; Wiśniewski, A.; Przeździecki, M.; Valde-Nowak, P.; Muzyczuk, A.; Davies, L.; Morgan, P.; Aydar, E.; Çubukçu, E.; Brown, R.; Coltelli, M.; Lo Castro, D.; Cioni, R.; DeRosa, R.; Donato, P.; Di Roberto, A.; Gertisser, R.; Giordano, G.; Branney, M.; Jordan, N.; Keller, J.; Kinvig, H.; Gottsman, J.; Blundy, J.; Marani, M.; Orsi, G.; Civetta, L.; Arienzo, I.; Carandente, A.; Rosi, M.; Zanchetta, G.; Seghedi, I.; Szakacs, A.; Sulpizio, R.; Thordarson, T.; Trincardi, F.; Vigliotti, L.; Asioli, A.; Piva, A.; Andrič, M.; Brauer, A.; de Klerk, P.; Filippi, M.-L.; Finsinger, W.; Galović, L.; Jones, T.; Lotter, A.; Müller, U.; Pross, J.; Mangerud, J.; Lohne, Ø.; Pyne-O'Donnell, S.; Markovic, S.; Pini, R.; Ravazzi, C.; Theuerkauf, M.; Tzedakis, C.; Margari, V.; Veres, D.; Wastegård, S.; Ortiz, J. E.; Torres, T.; Díaz-Bautista, A.; Moreno, A.; Valero-Garcés, B.; Lowick, S.; Ottolini, L.

    2015-01-01

    Roč. 118, 15 June 2015 (2015), s. 1-17 ISSN 0277-3791 Institutional support: RVO:68081758 Keywords : Last Glacial stage * Dansgaard-Oeschger and Heinrich events * Abrupt environmental transitions (AETs) * Middle to Upper Palaeolithic * Volcanic ash isochrons * Tephra geochemistry * Tephra database Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 4.521, year: 2015

  20. Fall Enrollment Report. 2014

    Science.gov (United States)

    Iowa Department of Education, 2014

    2014-01-01

    This report summarizes and analyzes fall enrollment in Iowa's community colleges. Each year, Iowa's 15 community colleges submit data on enrollment on the 10th business day of the fall semester. Some highlights from this report include: (1) Fall 2014 enrollment was 93,772 students--a decline of 0.49 percent from last fall; (2) Enrollment continues…

  1. Introducing Geoscience Students to Numerical Modeling of Volcanic Hazards: The example of Tephra2 on VHub.org

    Directory of Open Access Journals (Sweden)

    Leah M. Courtland

    2012-07-01

    Full Text Available The Tephra2 numerical model for tephra fallout from explosive volcanic eruptions is specifically designed to enable students to probe ideas in model literacy, including code validation and verification, the role of simplifying assumptions, and the concepts of uncertainty and forecasting. This numerical model is implemented on the VHub.org website, a venture in cyberinfrastructure that brings together volcanological models and educational materials. The VHub.org resource provides students with the ability to explore and execute sophisticated numerical models like Tephra2. We present a strategy for using this model to introduce university students to key concepts in the use and evaluation of Tephra2 for probabilistic forecasting of volcanic hazards. Through this critical examination students are encouraged to develop a deeper understanding of the applicability and limitations of hazard models. Although the model and applications are intended for use in both introductory and advanced geoscience courses, they could easily be adapted to work in other disciplines, such as astronomy, physics, computational methods, data analysis, or computer science.

  2. Preventing falls and fractures.

    Science.gov (United States)

    Ulfarsson, J; Robinson, B E

    1994-11-01

    One of four persons over age 65 in the community falls; those over age 75 in institutions fall more frequently. Falls, a complex phenomena suggesting present disease and predicting future disability, are caused by interactions between the environment and dynamic balance which is determined by the quality of sensory input, central processing, and motor responses. Clinical factors which predispose to falling often produce observable disturbances in gait and balance, making observation critical in assessment. Acute illness and drug therapy produce particularly preventable falls. Therapeutic exercise and environmental modification for safety are the clinical interventions most likely to successfully prevent fall-related injury.

  3. Luminescence property of volcanic quartz and the use of red isothermal TL for dating tephras

    International Nuclear Information System (INIS)

    Tsukamoto, S.; Murray, A.S.; Huot, S.; Watanuki, T.; Denby, P.M.; Botter-Jensen, L.

    2007-01-01

    An optically stimulated luminescence (OSL) age obtained from a Japanese tephra using quartz phenocrysts severely underestimated the known age. The characteristics of the OSL signals were investigated in order to understand the cause of the underestimation; the main OSL component of volcanic quartz has a thermodynamic lifetime of about 1700 years at room temperature, and it also seems to fade anomalously (i.e. athermally). Measurement of conventional red thermoluminescence (RTL) using a Ga-As photomultiplier tube was difficult due to the presence of a strong thermal background, although RTL gave an age consistent with the independent age. Furthermore, red isothermal TL (RITL) at 380 deg. C allowed the RTL signal to be separated from to the thermal background, and RITL ages of three volcanic quartz samples show good agreement with independent ages

  4. A quantitative X-ray diffraction inventory of the tephra and volcanic glass inputs into the Holocene marine sediment archives off Iceland: A contribution to V.A.S.T.

    Science.gov (United States)

    Andrews, John T.; Kristjansdottir, Greta B.; Eberl, Dennis D.; Jennings, Anne E.

    2013-01-01

    This paper re-evaluates how well quantitative x-ray diffraction (qXRD) can be used as an exploratory method of the weight percentage (wt%) of volcaniclastic sediment, and to identify tephra events in marine cores. In the widely used RockJock v6 software programme, qXRD tephra and glass standards include the rhyodacite White River tephra (Alaska), a rhyolitic tephra (Hekla-4) and the basaltic Saksunarvatn tephra. Experiments of adding known wt% of tephra to felsic bedrock samples indicated that additions ≥10 wt% are accurately detected, but reliable estimates of lesser amounts are masked by amorphous material produced by milling. Volcaniclastic inputs range between 20 and 50 wt%. Primary tephra events are identified as peaks in residual qXRD glass wt% from fourth-order polynomial fits. In cores where tephras have been identified by shard counts in the > 150 µm fraction, there is a positive correlation (validation) with peaks in the wt% glass estimated by qXRD. Geochemistry of tephra shards confirms the presence of several Hekla-sourced tephras in cores B997-317PC1 and -319PC2 on the northern Iceland shelf. In core B997-338 (north-west Iceland), there are two rhyolitic tephras separated by ca. 100 cm with uncorrected radiocarbon dates on articulated shells of around 13 000 yr B.P. These tephras may be correlatives of the Borrobol and Penifiler tephras found in Scotland. The number of Holocene tephra events per 1000 yr was estimated from qXRD on 16 cores and showed a bimodal distribution with an increased number of events in both the late and early Holocene.

  5. Ages of 24 widespread tephras erupted since 30,000 years ago in New Zealand, with re-evaluation of the timing and palaeoclimatic implications of the Lateglacial cool episode recorded at Kaipo bog

    Science.gov (United States)

    Lowe, David J.; Blaauw, Maarten; Hogg, Alan G.; Newnham, Rewi M.

    2013-08-01

    Tephras are important for the NZ-INTIMATE project because they link all three records comprising the composite inter-regional stratotype developed for the New Zealand climate event stratigraphy (NZ-CES). Here we firstly report new calendar ages for 24 widespread marker tephras erupted since 30,000 calendar (cal.) years ago in New Zealand to help facilitate their use as chronostratigraphic dating tools for the NZ-CES and for other palaeoenvironmental and geological applications. The selected tephras comprise 12 rhyolitic tephras from Taupo, nine rhyolitic tephras from Okataina, one peralkaline rhyolitic tephra from Tuhua, and one andesitic tephra each from Tongariro and Egmont/Taranaki volcanic centres. Age models for the tephras were obtained using three methods: (i) 14C-based wiggle-match dating of wood from trees killed by volcanic eruptions (these dates published previously); (ii) flexible depositional modelling of a high-resolution 14C-dated age-depth sequence at Kaipo bog using two Bayesian-based modelling programs, Bacon and OxCal's P_Sequence function, and the IntCal09 data set (with SH offset correction -44 ± 17 yr); and (iii) calibration of 14C ages using OxCal's Tau_Boundary function and the SHCal04 and IntCal09 data sets. Our preferred dates or calibrated ages for the 24 tephras are as follows (youngest to oldest, all mid-point or mean ages of 95% probability ranges): Kaharoa AD 1314 ± 12; Taupo (Unit Y) AD 232 ± 10; Mapara (Unit X) 2059 ± 118 cal. yr BP; Whakaipo (Unit V) 2800 ± 60 cal. yr BP; Waimihia (Unit S) 3401 ± 108 cal. yr BP; Stent (Unit Q) 4322 ± 112 cal. yr BP; Unit K 5111 ± 210 cal. yr BP; Whakatane 5526 ± 145 cal. yr BP; Tuhua 6577 ± 547 cal. yr BP; Mamaku 7940 ± 257 cal. yr BP; Rotoma 9423 ± 120 cal. yr BP; Opepe (Unit E) 9991 ± 160 cal. yr BP; Poronui (Unit C) 11,170 ± 115 cal. yr BP; Karapiti (Unit B) 11,460 ± 172 cal. yr BP; Okupata 11,767 ± 192 cal. yr BP; Konini (bed b) 11,880 ± 183 cal. yr BP; Waiohau 14,009 ± 155

  6. Falls in multiple sclerosis.

    Science.gov (United States)

    Matsuda, Patricia N; Shumway-Cook, Anne; Bamer, Alyssa M; Johnson, Shana L; Amtmann, Dagmar; Kraft, George H

    2011-07-01

    To examine incidence, associated factors, and health care provider (HCP) response to falls in persons with multiple sclerosis (MS). Cross-sectional retrospective design. Community setting. Four hundred seventy-four persons with MS. Mailed survey questionnaire examined incidence, risk factors, and HCP response to falls in persons with MS who were dwelling in the community. Univariate and multiple ordinal regression analysis identified variables associated with single and multiple falls. Falls, causes and perceived reasons for falls, and HCP response. A total of 265 participants (58.2%) reported one or more falls in the previous 6 months, and 58.5% of falls were medically injurious. Trips/slips while walking accounted for 48% of falls. Factors associated with falls included use of a cane or walker (odds ratio [OR] 2.62; 95% confidence interval [CI] 1.66-4.14), income falls; recommended strategies included safety strategies (53.2%), use of gait assistive devices (42.1%), exercise/balance training (22.2%), and home modifications (16.6%). Factors associated with falls in persons with MS are similar to those in other populations with neurologic diseases. Despite the high incidence of falls, fewer than 50% of people with MS receive information about prevention of falls from an HCP. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  7. Home Improvements Prevent Falls

    Science.gov (United States)

    ... turn JavaScript on. Feature: Falls and Older Adults Home Improvements Prevent Falls Past Issues / Winter 2014 Table ... and ensure your safety. "Safe-ty-fy" Your Home Some Questions for Your Provider Will my medicines ...

  8. The effect of the sea on hazard assessment for tephra fallout at Campi Flegrei: a preliminary approach through the use of pyPHaz, an open tool to analyze and visualize probabilistic hazards

    Science.gov (United States)

    Tonini, Roberto; Sandri, Laura; Costa, Antonio; Selva, Jacopo

    2014-05-01

    Campi Flegrei (CF) is a large volcanic field located west of the Gulf of Naples, characterized by a wide and almost circular caldera which is partially submerged beneath the Gulf of Pozzuoli. It is known that the magma-water interaction is a key element to determine the character of submarine eruptions and their impact on the surrounding areas, but this phenomenon is still not well understood and it is rarely considered in hazard assessment. The aim of the present work is to present a preliminary study of the effect of the sea on the tephra fall hazard from CF on the municipality of Naples, by introducing a variability in the probability of tephra production according to the eruptive scale (defined on the basis of the erupted volume) and the depth of the opening submerged vents. Four different Probabilistic Volcanic Hazard Assessment (PVHA) models have been defined through the application of the model BET_VH at CF, by accounting for different modeling procedures and assumptions for the submerged part of the caldera. In particular, we take into account: 1) the effect of the sea as null, i.e. as if the water were not present; 2) the effect of the sea as a cap that totally blocks the explosivity of eruptions and consequently the tephra production; 3) an ensemble model between the two models described at the previous points 1) and 2); 4) a variable probability of tephra production depending on the depth of the submerged vent. The PVHA models are then input to pyPHaz, a tool developed and designed at INGV to visualize, analyze and merge into ensemble models PVHA's results and, potentially, any other kind of probabilistic hazard assessment, both natural and anthropic, in order to evaluate the importance of considering a variability among subaerial and submerged vents on tephra fallout hazard from CF in Naples. The analysis is preliminary and does not pretend to be exhaustive, but on one hand it represents a starting point for future works; on the other hand, it is a good

  9. Falls in older people

    NARCIS (Netherlands)

    van Dieën, Jaap H.; Pijnappels, Mirjam

    Falls are common incidents, which can have major con-sequences. For example, falls and the interrelated category of accidents being struck by or against objects account for more than 40% of injuries and 30% of injury costs in the USA (Corso et al., 2006). Especially among older adults, falls occur

  10. Falls in Parkinson's disease.

    NARCIS (Netherlands)

    Grimbergen, Y.A.M.; Munneke, M.; Bloem, B.R.

    2004-01-01

    PURPOSE OF REVIEW: To summarize the latest insights into the clinical significance, assessment, pathophysiology and treatment of falls in Parkinson's disease. RECENT FINDINGS: Recent studies have shown that falls are common in Parkinson's disease, even when compared with other fall-prone

  11. Fall Prevention: Simple Tips to Prevent Falls

    Science.gov (United States)

    ... a gentle exercise that involves slow and graceful dance-like movements. Such activities reduce the risk of ... healthy-lifestyle/healthy-aging/in-depth/fall-prevention/art-20047358 . Mayo Clinic Footer Legal Conditions and Terms ...

  12. Tephrostratigraphy and Provenance From IODP Expedition 352, Izu-Bonin Arc: Tracing Tephra Sources and Volumes From the Oligocene to Recent

    Science.gov (United States)

    Kutterolf, S.; Schindlbeck, J. C.; Robertson, A. H. F.; Avery, A.; Baxter, A. T.; Petronotis, K.; Wang, K.-L.

    2018-01-01

    Provenance studies of widely distributed tephras, integrated within a well-defined temporal framework, are important to deduce systematic changes in the source, scale, distribution, and changes in regional explosive volcanism. Here, we establish a robust tephrochronostratigraphy for a total of 157 marine tephra layers collected during IODP Expedition 352. We infer at least three major phases of highly explosive volcanism during Oligocene to Pleistocene time. Provenance analysis based on glass composition assigns 56 of the tephras to a Japan source, including correlations with 12 major and widespread tephra layers resulting from individual eruptions in Kyushu, Central Japan, and North Japan between 115 ka and 3.5 Ma. The remaining 101 tephras are assigned to four source regions along the Izu-Bonin arc. One, exclusively assigned to the Oligocene age, is proximal to the Bonin Ridge islands; two reflect eruptions within the volcanic front and back-arc of the central Izu-Bonin arc, and a fourth region corresponds to the Northern Izu-Bonin arc source. First-order volume estimates imply eruptive magnitudes ranging from 6.3 to 7.6 for Japan-related eruptions and between 5.5 and 6.5 for IBM eruptions. Our results suggest tephras between 30 and 22 Ma reflect a subtly different Izu-Bonin chemical signature compared to the recent arc. After a ˜9 Ma gap in eruption, tephra supply from the Izu-Bonin arc predominated from 15 to 5 Ma, and finally a subequal mixture of tephra sources from the (palaeo)Honshu and Izu-Bonin arcs occured within the last ˜5 Ma.

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

    Science.gov (United States)

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

    1984-01-01

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

  14. Geothermal flux through palagonitized tephra, Surtsey, Iceland - The Surtsey temperature-data-relay experiment via Landsat-1

    Science.gov (United States)

    Friedman, J. D.; Preble, D. M.; Jakobsson, S.

    1976-01-01

    The net geothermal flux through palagonitized basaltic tephra rims of the Surtur I and Surtur II craters at Surtsey, Iceland, in 1972, is estimated at 780 plus or minus 325 microcal/sq cm/s, indicating a decline since 1969 when a flux of 1500 microcal/sq cm/s was estimated. Heat flux in this range characterizes the postvolcanic environment on Surtsey in which the subaerial polagonitization of basaltic tephra is associated with mass transfer of hydrothermal vapor, either of meteoric or sea-water origin, only a few years after cessation of eruptive activity. The flux estimation is the result of the Surtsey data-relay experiment via Landsat-1 which was carried out in several phases. Temperature data were transmitted for a 38-day period in November and December 1972. A near-surface vertical gradient of 69.4 C/m was obtained, suggesting a mixed mechanism of heat transfer, partitioned between conduction and convection.

  15. Spores of coprophilous fungi from under the Dawson tephra (25,300 14C years BP), Yukon Territory, northwestern Canada

    NARCIS (Netherlands)

    van Geel, B.; Zazula, G.D.; Schweger, C.E.

    2007-01-01

    Based on the analysis of pollen and macrofossils Zazula et al. [Zazula, G.D., Froesne, D.G., Elias, S.A., Kuzmina, S., la Farge, C., Reyes, A.V., Sanborn, P.T., Schweger, C.E., Smith, C.A.S., Mathewes, R.W., 2006. Vegetation buried under Dawson tephra (25,300 14C yr BP) and locally diverse late

  16. A Tephra Database With an Intelligent Correlation System, Mono-Inyo Volcanic Chain, CA

    Science.gov (United States)

    Bursik, M.; Rogova, G.

    2004-12-01

    We are assembling a web-accessible, relational database of information on past eruptions of the Mono-Inyo volcanic chain, eastern California. The PostgreSQL database structure follows the North American Data Model and CordLink. The database allows us to extract the features diagnostic of particular pyroclastic layers, as well as lava domes and flows. The features include depth in the section, layer thickness and internal stratigraphy, mineral assemblage, major and trace element composition, tephra componentry and granulometry, and radiocarbon age. Our working hypotheses are that 1) the database will prove useful for unraveling the complex recent volcanic history of the Mono-Inyo chain 2) aided by the use of an intelligent correlation system integrated into the database system. The Mono-Inyo chain consists of domes, craters and flows that stretch for 50 km north-south, subparallel to the Sierran range front fault system. Almost all eruptions within the chain probably occurred less than 50,000 years ago. Because of the variety of magma and eruption types, and the migration of source regions in time and space, it is nontrivial to discern patterns of behaviour. We have explored the use of multiple artificial neural networks combined within the framework of the Dempster-Shafer theory of evidence to construct a hybrid information processing system as an aid in the correlation of Mono-Inyo pyroclastic layers. It is hoped that such a system could provide information useful to discerning eruptive patterns that would otherwise be difficult to sort and categorize. In a test case on tephra layers at known sites, the intelligent correlation system was able to categorize observations correctly 96% of the time. In a test case with layers at one unknown site, and using a pairwise comparison of the unknown site with the known sites, a one-to-one correlation between the unknown site and the known sites was found to sometimes be poor. Such a result could be used to aid a

  17. Acid Deposition Phenomena

    International Nuclear Information System (INIS)

    Ramadan, A.E.K.

    2004-01-01

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H 2 SO 4 ) and nitric acids (HNO 3 ), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  18. The effect of wind and eruption source parameter variations on tephra fallout hazard assessment: an example from Vesuvio (Italy)

    Science.gov (United States)

    Macedonio, Giovanni; Costa, Antonio; Scollo, Simona; Neri, Augusto

    2015-04-01

    Uncertainty in the tephra fallout hazard assessment may depend on different meteorological datasets and eruptive source parameters used in the modelling. We present a statistical study to analyze this uncertainty in the case of a sub-Plinian eruption of Vesuvius of VEI = 4, column height of 18 km and total erupted mass of 5 × 1011 kg. The hazard assessment for tephra fallout is performed using the advection-diffusion model Hazmap. Firstly, we analyze statistically different meteorological datasets: i) from the daily atmospheric soundings of the stations located in Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012, and in Pratica di Mare (Rome, Italy) between 1996 and 2012; ii) from numerical weather prediction models of the National Oceanic and Atmospheric Administration and of the European Centre for Medium-Range Weather Forecasts. Furthermore, we modify the total mass, the total grain-size distribution, the eruption column height, and the diffusion coefficient. Then, we quantify the impact that different datasets and model input parameters have on the probability maps. Results shows that the parameter that mostly affects the tephra fallout probability maps, keeping constant the total mass, is the particle terminal settling velocity, which is a function of the total grain-size distribution, particle density and shape. Differently, the evaluation of the hazard assessment weakly depends on the use of different meteorological datasets, column height and diffusion coefficient.

  19. Meteorite falls in Africa

    Science.gov (United States)

    Khiri, Fouad; Ibhi, Abderrahmane; Saint-Gerant, Thierry; Medjkane, Mohand; Ouknine, Lahcen

    2017-10-01

    The study of meteorites provides insight into the earliest history of our solar system. From 1800, about the year meteorites were first recognized as objects falling from the sky, until December 2014, 158 observed meteorite falls were recorded in Africa. Their collected mass ranges from 1.4 g to 175 kg with the 1-10 kg cases predominant. The average rate of African falls is low with only one fall recovery per 1.35-year time interval (or 0.023 per year per million km2). This African collection is dominated by ordinary chondrites (78%) just like in the worldwide falls. The seventeen achondrites include three Martian meteorite falls (Nakhla of Egypt, Tissint of Morocco and Zagami of Nigeria). Observed Iron meteorite falls are relatively rare and represent only 5%. The falls' rate in Africa is variable in time and in space. The number of falls continues to grow since 1860, 80% of which were recovered during the period between 1910 and 2014. Most of these documented meteorite falls have been recovered from North-Western Africa, Eastern Africa and Southern Africa. They are concentrated in countries which have a large surface area and a large population with a uniform distribution. Other factors are also favorable for observing and collecting meteorite falls across the African territory, such as: a genuine meteorite education, a semi-arid to arid climate (clear sky throughout the year most of the time), croplands or sparse grasslands and possible access to the fall location with a low percentage of forest cover and dense road network.

  20. Preventing falls in hospital.

    Science.gov (United States)

    Pearce, Lynne

    2017-02-27

    Essential facts Falls are the most frequent adverse event reported in hospitals, usually affecting older patients. Every year, more than 240,000 falls are reported in acute hospitals and mental health trusts in England and Wales, equivalent to more than 600 a day, according to the Royal College of Physicians (RCP). But research shows that when nurses, doctors and therapists work together, falls can be reduced by 20-30%.

  1. Insights into the Toba Super-Eruption using SEM Analysis of Ash Deposits

    Science.gov (United States)

    Gatti, E.; Achyuthan, H.; Durant, A. J.; Gibbard, P.; Mokhtar, S.; Oppenheimer, C.; Raj, R.; Shridar, A.

    2010-12-01

    The ~74 ka Youngest Toba Tuff (YTT) super-eruption of Toba volcano, Northern Sumatra, was the largest eruption of the Quaternary (magnitude M= 8.8) and injected massive quantities of volcanic gases and ash into the stratosphere. YTT deposits covered at least 40,000,000 km2 of Southeast Asia and are preserved in river valleys across peninsular India and Malaysia, and in deep-sea tephra layers in the Indian Ocean, Bay of Bengal and South China Sea. Initial studies hypothesized the eruption caused immediate and substantial global cooling during the ~ 1 kyr between Dansgaard-Oeschger events 19 and 20 which devastated ecosystems and hominid populations. A more recent review argues against severe post-YTT climatic deterioration and cannot find clear evidence for considerable impacts on ecosystems or bio-diversity. The determination of the eruptive parameters is crucial in this issue to document the eruption and understand the potential impacts from future super-volcanic eruptions. Volcanic ash deposits can offer dramatic insights into key eruptive parameters, including magnitude, duration and plume height. The composition and shape of volcanic ashes can be used to interpret physical properties of an erupting magma and tephra transport, while textural characteristics such as grain roughness and surface vescicularity can provide insights into degassing history, volatile content and explosive activity of the volcano. We present a stratigraphic and sedimentological analysis of YTT deposits in stratified contexts at three localities in India, at two sites in Peninsular Malaysia, and at several localities around Lake Toba and on Samosir Island, Sumatra. These sites offer excellent constraints on the spatial distribution of YTT deposits which can be used to infer dispersal directions of the cloud, and provide insights into environmental controls on preservation of tephra beds. The research aims at a systematic interpretation of the Toba tephra to understand the volcanic

  2. Remarkably preserved tephra from the 3430 Ma Strelley Pool Formation, Western Australia: Implications for the interpretation of Precambrian microfossils

    Science.gov (United States)

    Wacey, David; Saunders, Martin; Kong, Charlie

    2018-04-01

    The ∼3430 Ma Strelley Pool Formation (SPF), Pilbara, Western Australia contains some of the most diverse microfossil evidence for early life on Earth. Here we report an assemblage of tephra (scoria, tubular pumice, plus vesicular and non-vesicular volcanic glass shards) from two stratigraphic levels in the SPF, including morphotypes that closely resemble previously described microfossils from this unit and elsewhere. Clasts of scoria are characterised by numerous spheroidal vesicles, with subordinate eye- and lens-shaped morphotypes, commonly lined with anatase (TiO2) and small amounts of organic material. Their diameters range from 5-180 μm with 80% in the 10-50 μm range. Fragments of tubular pumice are also lined with anatase + / - carbon and have tube diameters of 5-15 μm. Other volcanic ejecta particles include a multitude of sub-angular shard particles with or without vesicles, plus more rounded vase-shaped, eye-shaped, and hair-like morphologies; once again, most of these are coated by anatase + / - carbon and are several tens of micrometres in size. Many of the tephra fragments are now entirely silicified with no compositional difference between the former volcanic glass, the vesicle infill and the clast matrix. However, some examples retain a partial aluminosilicate composition, either as a vesicle infilling phase or as isolated lath-like grains within the formerly glassy groundmass. Isolated occurrences of some of these tephra morphotypes strongly resemble simple microbial morphologies including pairs and clusters of cells (cf. scoria), filamentous microbes (cf. tubular pumice) and larger sheaths/cysts (cf. sub-rounded glass shards). Furthermore, some tephra-containing clasts occur in a SPF sandstone unit that hosts previously described microfossils, while others are interbedded with chert layers from which microfossils have also been described. In light of our new volcanogenic data, we evaluate the robustness of previous microfossil evidence from the

  3. Falls and comorbidity

    DEFF Research Database (Denmark)

    Jørgensen, Terese Sara Høj; Hansen, Annette Højmann; Sahlberg, Marie

    2014-01-01

    AIMS: To compare nationwide time trends and mortality in hip and proximal humeral fractures; to explore associations between incidences of falls risk related comorbidities (FRICs) and incidence of fractures. METHODS: The study is a retrospective cohort study using nationwide Danish administrative....... CONCLUSIONS: The results suggest that the overall reduction in fractures can be explained by reduction in falls related comorbidity....

  4. An update on falls

    NARCIS (Netherlands)

    Bloem, B.R.; Steijns, J.A.G.; Smits-Engelsman, B.C.M.

    2003-01-01

    Purpose of review: Falls among elderly persons create immense social problems because of their association with physical decline, serious psychosocial consequences, negative impact on the quality of life, and markedly reduced survival. In addition, falls pose high costs to the public health service.

  5. An update on falls.

    NARCIS (Netherlands)

    Bloem, B.R.; Steijns, J.A.G.; Smits-Engelsman, B.C.M.

    2003-01-01

    PURPOSE OF REVIEW: Falls among elderly persons create immense social problems because of their association with physical decline, serious psychosocial consequences, negative impact on the quality of life, and markedly reduced survival. In addition, falls pose high costs to the public health service.

  6. First Aid: Falls

    Science.gov (United States)

    ... Folleto de instructiones: Caídas (Falls) With all the running, climbing, and exploring kids do, it's no surprise that falls are common. Although many result in mild bumps, cuts, and bruises, some can cause serious injuries that need immediate medical attention. What to Do ...

  7. Dry deposition on urban surfaces

    International Nuclear Information System (INIS)

    Roed, J.

    1985-01-01

    In order to facilitate developing a model for deposition in urban areas, beryllium-7, created by cosmic radiation and fall-out cesium-137, have been used as tracers in measurements designed to find the dry deposition velocity on building surfaces. A literature review has revealed that very little work has been done on deposition in urban areas; therefore, a major effort on meausring the deposition parameter is needed to construct reliable models in this field. Deposition velocities in the range from 0.001-0.04 cm/s have been found. (author)

  8. Investigation and hazard assessment of the 2003 and 2007 Staircase Falls rock falls, Yosemite National Park, California, USA

    Directory of Open Access Journals (Sweden)

    G. F. Wieczorek

    2008-05-01

    Full Text Available Since 1857 more than 600 rock falls, rock slides, debris slides, and debris flows have been documented in Yosemite National Park, with rock falls in Yosemite Valley representing the majority of the events. On 26 December 2003, a rock fall originating from west of Glacier Point sent approximately 200 m3 of rock debris down a series of joint-controlled ledges to the floor of Yosemite Valley. The debris impacted talus near the base of Staircase Falls, producing fragments of flying rock that struck occupied cabins in Curry Village. Several years later on 9 June 2007, and again on 26 July 2007, smaller rock falls originated from the same source area. The 26 December 2003 event coincided with a severe winter storm and was likely triggered by precipitation and/or frost wedging, but the 9 June and 26 July 2007 events lack recognizable triggering mechanisms. We investigated the geologic and hydrologic factors contributing to the Staircase Falls rock falls, including bedrock lithology, weathering, joint spacing and orientations, and hydrologic processes affecting slope stability. We improved upon previous geomorphic assessment of rock-fall hazards, based on a shadow angle approach, by using STONE, a three-dimensional rock-fall simulation computer program. STONE produced simulated rock-fall runout patterns similar to the mapped extent of the 2003 and 2007 events, allowing us to simulate potential future rock falls from the Staircase Falls detachment area. Observations of recent rock falls, mapping of rock debris, and simulations of rock fall runouts beneath the Staircase Falls detachment area suggest that rock-fall hazard zones extend farther downslope than the extent previously defined by mapped surface talus deposits.

  9. Investigation and hazard assessment of the 2003 and 2007 Staircase Falls rock falls, Yosemite National Park, California, USA

    Science.gov (United States)

    Wieczorek, G. F.; Stock, G. M.; Reichenbach, P.; Snyder, J. B.; Borchers, J. W.; Godt, J. W.

    2008-05-01

    Since 1857 more than 600 rock falls, rock slides, debris slides, and debris flows have been documented in Yosemite National Park, with rock falls in Yosemite Valley representing the majority of the events. On 26 December 2003, a rock fall originating from west of Glacier Point sent approximately 200 m3 of rock debris down a series of joint-controlled ledges to the floor of Yosemite Valley. The debris impacted talus near the base of Staircase Falls, producing fragments of flying rock that struck occupied cabins in Curry Village. Several years later on 9 June 2007, and again on 26 July 2007, smaller rock falls originated from the same source area. The 26 December 2003 event coincided with a severe winter storm and was likely triggered by precipitation and/or frost wedging, but the 9 June and 26 July 2007 events lack recognizable triggering mechanisms. We investigated the geologic and hydrologic factors contributing to the Staircase Falls rock falls, including bedrock lithology, weathering, joint spacing and orientations, and hydrologic processes affecting slope stability. We improved upon previous geomorphic assessment of rock-fall hazards, based on a shadow angle approach, by using STONE, a three-dimensional rock-fall simulation computer program. STONE produced simulated rock-fall runout patterns similar to the mapped extent of the 2003 and 2007 events, allowing us to simulate potential future rock falls from the Staircase Falls detachment area. Observations of recent rock falls, mapping of rock debris, and simulations of rock fall runouts beneath the Staircase Falls detachment area suggest that rock-fall hazard zones extend farther downslope than the extent previously defined by mapped surface talus deposits.

  10. Acoustic and tephra records of explosive eruptions at West Mata submarine volcano, NE Lau Basin

    Science.gov (United States)

    Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Mack, C. J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T. A.

    2013-12-01

    West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were directly observed in May 2009. Here we present long-term acoustic and tephra records of West Mata explosion activity from three deployments of hydrophone and particle sensor moorings beginning on 8 January 2009. These records provide insights into the character of explosive magma degassing occurring at the volcano's summit vent until the decline and eventual cessation of the eruption during late 2010 and early 2011. The detailed acoustic records show three types of volcanic signals, 1) discrete explosions, 2) diffuse explosions, and 3) volcanic tremor. Discrete explosions are short duration, high amplitude broad-band signals caused by rapid gas bubble release. Diffuse signals are likely a result of 'trap-door' explosions where a quench cap of cooled lava forms over the magmatic vent but gas pressure builds underneath the cap. This pressure eventually causes the cap to breach and gas is explosively released until pressure reduces and the cap once again forms. Volcanic tremor is typified by narrow-band, long-duration signals with overtones, as well as narrow-band tones that vary frequency over time between 60-100 Hz. The harmonic tremor is thought to be caused by modulation of rapid, short duration gas explosion pulses and not a magma resonance phenomenon. The variable frequency tones may be caused by focused degassing or hydrothermal fluid flow from a narrow volcanic vent or conduit. High frequency (>30 Hz) tremor-like bands of energy are a result of interference caused by multipath wide-band signals, including sea-surface reflected acoustic phases, that arrive at the hydrophone with small time delays. Acoustic data suggest that eruption velocities for a single explosion range from 4-50 m s-1, although synchronous arrival of explosion signals has complicated our efforts to estimate long-term gas flux. Single explosions exhibit ~4-40 m3 s-1 of total volume flux (gas and rock) but

  11. Stratigraphy and chronology of a 15 ka sequence of multi-sourced silicic tephras in a montane peat bog, eastern North Island, New Zealand

    International Nuclear Information System (INIS)

    Lowe, D.J.; Newnham, R.M.; Ward, C.M.

    1999-01-01

    We document the stratigraphy, composition, and chronology of a succession of 16 distal, silicic tephra layers interbedded with lateglacial and Holocene peats and muds up to c. 15 000 radiocarbon years (c. 18 000 calendar years) old at a montane site (Kaipo Bog) in eastern North Island, New Zealand. Aged from 665 + or - 15 to 14 700 + or - 95 14 C yr BP, the tephras are derived from six volcanic centres in North Island, three of which are rhyolitic (Okataina, Taupo, Maroa), one peralkaline (Tuhua), and two andesitic (Tongariro, Egmont). Correlations are based on multiple criteria: field properties and stratigraphic interrelationships, ferromagnesian silicate mineral assemblages, glass-shard major element composition (from electron microprobe analysis), and radiocarbon dating. We extend the known distribution of tephras in eastern North Island and provide compositional data that add to their potential usefulness as isochronous markers. The chronostratigraphic framework established for the Kaipo sequence, based on both site-specific and independently derived tephra-based radiocarbon ages, provides the basis for fine-resolution paleoenvironmental studies at a climatically sensitive terrestrial site from the mid latitudes of the Southern Hemisphere. Tephras identified as especially useful paleoenvironmental markers include Rerewhakaaitu and Waiohau (lateglacial), Konini (late-glacial-early Holocene), Tuhua (middle Holocene), and Taupo and Kaharoa (late Holocene). (author). 102 refs., 3 tabs., 3 figs

  12. Implications of S1 tephra findings in Dead Sea and Tayma palaeolake sediments for marine reservoir age estimation and palaeoclimate synchronisation

    Science.gov (United States)

    Neugebauer, Ina; Wulf, Sabine; Schwab, Markus J.; Serb, Johanna; Plessen, Birgit; Appelt, Oona; Brauer, Achim

    2017-08-01

    Here we report on the first findings of a cryptotephra in the Holocene lacustrine sediment records of the Dead Sea and Tayma palaeolake (NW Arabian Peninsula). The major element glass composition of this rhyolitic tephra is identical to the distal 'S1' tephra layer identified in the Yammoûneh palaeolake (Lebanon), in a marine sediment record from the SE Levantine basin and in the Sodmein Cave archaeological site in Egypt. The S1 tephra corresponds to the early Holocene 'Dikkartın' dome eruption of the Erciyes Dağ volcano in central Anatolia (Turkey) and has been dated in the marine record at 8830 ± 140 cal yr BP. We present new age estimates of the S1 tephra based on radiocarbon dating of terrestrial plant remains and pollen concentrates revealing ages of 8939 ± 83 cal yr BP in the Dead Sea sediments and 9041 ± 254 cal yr BP in Tayma. The precise date from the Dead Sea allows refining the early Holocene marine reservoir age in the SE Levantine Sea to ca. 320 ± 50 years. Synchronisation of marine and terrestrial palaeoclimate records in the eastern Mediterranean region using the S1 tephra further suggests a time-transgressive expansion of the early Holocene humid period.

  13. Geriatric fall-related injuries.

    African Journals Online (AJOL)

    Conclusion: The majority of geriatric fall-related injuries were due to fall from the same level at home. Assessment of risk fac- tors for falls including home hazards is essential for prevention of geriatric fall-related injuries. Keywords: Accidental fall, geriatrics, injury, trauma registry. DOI: http://dx.doi.org/10.4314/ahs.v16i2.24.

  14. Historical and paleo-tsunami deposits on Kamchatka, Russia: long-term chronologies and long-distance correlations

    Directory of Open Access Journals (Sweden)

    T. K. Pinegina

    2001-01-01

    Full Text Available Along the eastern coast of Kamchatka, at a number of localities, we have identified and attempted to assign ages to deposits of both historic and prehistoric (paleo- tsunamis. These deposits are dated and correlated using tephrochronology from Holocene marker tephra and local volcanic ash layers. Because the historical record of earthquakes and tsunamis on Kamchatka is so short, these investigations can make important contributions to evaluating tsunami hazards. Moreover, because even the historical record is spotty, our work helps add to and evaluate tsunami catalogues for Kamchatka. Furthermore, tsunami deposits provide a proxy record for large earthquakes and thus are important paleoseismological tools. The combined, preserved record of tsunami deposits and of numerous marker tephra on Kamchatka offers an unprecedented opportunity to study tsunami frequency. Using combined stratigraphic sections, we can examine both the average frequency of events for each locality, and also changes in frequency through time. Moreover, using key marker tephra as time lines, we can compare tsunami frequency and intensity records along the Kamchatka subduction zone. Preliminary results suggest real variations in frequency on a millennial time scale, with the period from about 0 to 1000 A.D. being particularly active at some localities.

  15. Fall Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years,...

  16. Catapults fall short

    Science.gov (United States)

    Gibson, Marcus

    2018-01-01

    In reply to the news story "UK Catapults fall short, claims review of technology centres", which describes an independent review that criticized the management of the UK's network of technology innovation centres.

  17. Survival of falling robots

    Science.gov (United States)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-01-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  18. Survival of falling robots

    Science.gov (United States)

    Cameron, Jonathan M.; Arkin, Ronald C.

    1992-02-01

    As mobile robots are used in more uncertain and dangerous environments, it will become important to design them so that they can survive falls. In this paper, we examine a number of mechanisms and strategies that animals use to withstand these potentially catastrophic events and extend them to the design of robots. A brief survey of several aspects of how common cats survive falls provides an understanding of the issues involved in preventing traumatic injury during a falling event. After outlining situations in which robots might fall, a number of factors affecting their survival are described. From this background, several robot design guidelines are derived. These include recommendations for the physical structure of the robot as well as requirements for the robot control architecture. A control architecture is proposed based on reactive control techniques and action-oriented perception that is geared to support this form of survival behavior.

  19. Historical volcanic eruptions in the Canary Islands, tephra composition, and insights into the crystal cargo of basaltic magmas

    Science.gov (United States)

    Longpre, M. A.; Muller, J.; Beaudry, P.; Andronikides, A.; Felpeto, A.

    2017-12-01

    Since the 16th century, at least 13 volcanic eruptions have occurred in the Canary Islands that formed monogenetic cinder cones and lava flow fields: 2 on Lanzarote, 4 on Tenerife, 6 on La Palma, and 1 on the submarine flank of El Hierro. Here we present a comprehensive new dataset of tephra composition for all 13 eruptions, comprising major and trace element data for bulk rocks and matrix glasses, as well as vesicularity and crystallinity measurements. In addition, we compile available volcanological and petrological information for specific eruptions, including estimates of lava flow area and volume. All lapilli samples show a vesicularity of 40-50 vol% and a vesicle-free crystallinity (crystals ≥ 250 µm) of 5-15 vol%. Modal mineralogy varies significantly between samples, typically consisting of olivine ± clinopyroxene ± Fe-Ti oxide ± plagioclase ± amphibole in different proportions. All but 2 tephras have basanite-tephrite bulk rock compositions. Lapilli from vents of the AD 1730-1736 Timanfaya eruption, Lanzarote, largely are basaltic, whereas the AD 1798 Chahorra eruption, Tenerife, produced phonotephrite tephra. These results are in agreement with published bulk lava flow data. Unsurprisingly, glass compositions are more evolved than bulk rocks and MgOglass is weakly positively correlated to MgObulk (MgOglass = 0.30*MgObulk + 2.11, R2 = 0.54). Both bulk rocks and glasses show strikingly similar multi-element diagram patterns, with strong enrichment relative to the bulk-silicate Earth and marked positive Nb and Ta and negative Pb anomalies — typical for ocean island basalts. Glass/bulk rock elemental ratios reveal systematic differences between samples that relate to their mineralogy; for example, Lanzarote tephras that lack significant clinopyroxene and Fe-Ti oxide crystals have higher Scglass/Scbulk and Vglass/Vbulk than Tenerife, La Palma and El Hierro samples that typically contain these minerals. Among all elements, K and P display the greatest

  20. Spatial variation in pollen and charcoal records in relation to the 665 yr BP Kaharoa tephra at Harataonga Bay, Great Barrier Island, northern New Zealand : preliminary results

    International Nuclear Information System (INIS)

    Horrocks, M.; Nichol, S.L.; Jones, M.D.; Shane, P.A.; Sutton, D.G.

    2001-01-01

    We present preliminary results of a pollen study examining spatial variability using the 665 14 C yr BP Kaharoa tephra as the key stratigraphic marker. Our aim is to highlight potential differences in pollen and charcoal profiles from adjacent sites, and to point out the implications of these differences for the interpretation of pollen records. Three sediment cores were taken from swampy ground behind foredunes at Harataonga Bay, a small catchment on Great Barrier Island. Core 1 provides a c. 5000 14 C yr record of the swamp and is typical of northern New Zealand pollen profiles in that the deforestation signal appears immediately after Kaharoa tephra. Cores 2 and 3, however, show this signal at least 1 m below the tephra layer. Also, artefact pollen of gourd Lagenaria, an introduced Polynesian cultigen, was found 80 cm below the tephra layer in Core 2. This apparent difference in the timing of the human signal may be explained by the occurrence of small-scale, highly localised fires that are not recorded at adjacent sites. This has implications for inferring date of human presence in extensive areas, such as regions or large catchments, from a small number of pollen cores taken from within those areas. An alternative explanation is that sediments in cores 2 and 3 have been reworked to a much greater extent than those in Core 1. This has implications for the use of tephra as critical data for events, particularly when using recent tephra such as Kaharoa for dating human presence when the necessary resolution is to decades or centuries rather than millenia. (author). 18 refs., 6 figs., 2 tabs

  1. Stratigraphy and depositional environments of the upper Pleistocene Chemehuevi Formation along the lower Colorado River

    Science.gov (United States)

    Malmon, Daniel V.; Howard, Keith A.; House, P. Kyle; Lundstrom, Scott C.; Pearthree, Philip A.; Sarna-Wojcicki, Andrei M.; Wan, Elmira; Wahl, David B.

    2011-01-01

    overlies the mud facies where the two are found together, contacts between the two occur over a range in elevation, and as a consequence, the sand and mud facies are similarly distributed both horizontally and vertically throughout the valley. Collectively, the outcrops of the formation lie below a smooth elevation envelope that slopes 50 percent more steeply than the historic (pre-Hoover Dam) valley, from nearly 150 m above the historic flood plain near the mouth of the Grand Canyon to less than 30 m above the flood plain at the head of the flood plain near Yuma, Arizona. The steepness of the valley at the peak of aggradation probably represents a depositional slope. Layers of fine grained volcanic tephra have been found below and within the Chemehuevi Formation at five widely separated sites, one of which is now submerged beneath Lake Mead. Major element geochemistry of glass shards from the four accessible tephra sites were analyzed. Three of the sampled tephra layers are interbedded within the Chemehuevi Formation, and a fourth tephra conformably underlies the formation. The three interbedded tephra layers are similar enough to one another that they are probably from the same eruptive unit, hereafter referred to as the Monkey Rock tephra bed. The other sample, which locally underlies the formation, is similar enough to the Monkey Rock tephra bed to suggest it is from the same volcanic source area; however, it may not be from the same eruption, and thus may not be the same age. On the basis of the stratigraphic contexts of chemically similar tephra layers found elsewhere in the Basin and Range, we suspect that the source area is the Mammoth Mountain dome complex in Long Valley, east-central California. Two samples of proximal Mammoth Mountain pumice were analyzed and produced geochemical signatures similar to all four of the Chemehuevi Formation tephra, supporting Mammoth Mountain as a possible source area. The Mammoth Mountain volcanic center produced eruptions between

  2. Rock-fall potential in the Yosemite Valley, California

    Science.gov (United States)

    Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

    1999-01-01

    We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

  3. The neurobiology of falls.

    Science.gov (United States)

    Fasano, Alfonso; Plotnik, Meir; Bove, Francesco; Berardelli, Alfredo

    2012-12-01

    Falling is a major clinical problem; especially, in elderly population as it often leads to fractures, immobilization, poor quality of life and life-span reduction. Given the growing body of evidences on the physiopathology of balance disorders in humans, in recent years the approach of research on falls has completely changed and new instruments and new definitions have been formulated. Among them, the definition of "idiopathic faller" (i.e. no overt cause for falling in a given subject) represented a milestone in building the "science of falling". This review deals with the new determinants of the neurobiology of falling: (1) the role of motor impairment and particularly of those "mild parkinsonian signs" frequently detectable in elderly subjects, (2) the role of executive and attentive resources when coping with obstacles, (3) the role of vascular lesions in "highest level gait disorder" (a condition tightly connected with senile gait, cautious gait and frailty), (4) the role of the failure of automaticity or inter-limbs coordination/symmetry during walking and such approach would definitely help the development of screening instrument for subjects at risk (still lacking in present days). This translational approach will lead to the development of specific therapeutic interventions.

  4. Fall Prevention Hits Stumbling Blocks.

    Science.gov (United States)

    Huff, Charlotte

    2018-03-01

    Implementation of efforts to screen older people for fall risk-and to intervene before falls occur-have been scattershot at best. Ongoing studies of fall prevention called STRIDE (Strategies to Reduce Injuries and Develop Confidence in Elders) might change that. The studies look at whether clinicians can implement a fall-prevention program across rural, urban, and suburban treatment settings.

  5. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, Chile

    Science.gov (United States)

    Frederick J. Swanson; Julia A. Jones; Charles M. Crisafulli; Antonio. Lara

    2013-01-01

    The 2008-2009 eruption of Chaiten Volcano (Chile) involved a variety of volcanic and associated hydrologic processes that damaged nearby forests. These processes included coarse (gravel) and fine (silt to sand) tephra fall, a laterally directed blast, fluvial deposition of remobilized tephra, a variety of low-temperature mass-movement processes, and a pyroclastic flow...

  6. Fear of falling as seen in the Multidisciplinary falls consultation.

    Science.gov (United States)

    Gaxatte, C; Nguyen, T; Chourabi, F; Salleron, J; Pardessus, V; Delabrière, I; Thévenon, A; Puisieux, F

    2011-06-01

    Fear of falling may be as debilitating as the fall itself, leading to a restriction in activities and even a loss of autonomy. The main objective was to evaluate the prevalence of the fear of falling among elderly fallers. The secondary objectives were to determine the factors associated with the fear of falling and evaluate the impact of this fear on the activity "getting out of the house". Prospective study conducted between 1995 and 2006 in which fallers and patients at high risk for falling were seen at baseline by the multidisciplinary falls consultation team (including a geriatrician, a neurologist and a physical medicine and rehabilitation physician) and then, again 6 month later, by the same geriatrician. The fear of falling was evaluated with a yes/no question: "are you afraid of falling?". Out of 635 patients with a mean age of 80.6 years, 502 patients (78%) expressed a fear of falling. Patients with fear of falling were not older than those who did not report this fear, but the former were mostly women (Pfear of falling were not going out alone as much as the fearless group (31% vs 53%, Pfearful group admitted to avoiding going out because they were afraid of falling. The strong prevalence of the fear of falling observed in this population and its consequences in terms of restricted activities justifies systematically screening for it in fallers or patients at risk for falling. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  7. Women's perspectives on falls and fall prevention during pregnancy.

    Science.gov (United States)

    Brewin, Dorothy; Naninni, Angela

    2014-01-01

    Falls are the leading cause of unintentional injury in women. During pregnancy, even a minor fall can result in adverse consequences. Evidence to inform effective and developmentally appropriate pregnancy fall prevention programs is lacking. Early research on pregnancy fall prevention suggests that exercise may reduce falls. However, acceptability and effectiveness of pregnancy fall prevention programs are untested. To better understand postpartum women's perspective and preferences on fall prevention strategies during pregnancy to formulate an intervention. Focus groups and individual interviews were conducted with 31 postpartum women using descriptive qualitative methodology. Discussion of falls during pregnancy and fall prevention strategies was guided by a focus group protocol and enhanced by 1- to 3-minute videos on proposed interventions. Focus groups were audio recorded, transcribed, and analyzed using NVivo 10 software. Emerging themes were environmental circumstances and physical changes of pregnancy leading to a fall, prevention strategies, barriers, safety concerns, and marketing a fall prevention program. Wet surfaces and inappropriate footwear commonly contributed to falls. Women preferred direct provider counseling and programs including yoga and Pilates. Fall prevention strategies tailored to pregnant women are needed. Perspectives of postpartum women support fall prevention through provider counseling and individual or supervised exercise programs.

  8. Fall Back Equilibrium

    NARCIS (Netherlands)

    Kleppe, J.; Borm, P.E.M.; Hendrickx, R.L.P.

    2008-01-01

    Fall back equilibrium is a refinement of the Nash equilibrium concept. In the underly- ing thought experiment each player faces the possibility that, after all players decided on their action, his chosen action turns out to be blocked. Therefore, each player has to decide beforehand on a back-up

  9. The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea

    DEFF Research Database (Denmark)

    Pearce, C.; Varhelyi, A.; Wastegård, S.

    2016-01-01

    is interpreted as sustained reworking at the sediment source input. The isochron is therefore placed at the base of the sudden increase in tephra concentrations rather than at the maximum concentration. This interpretation of major reworking is strengthened by analysis of grain size distribution which points...

  10. Occurrence of tephra/volcanic tuff in the tertiary sediments of Himachal Himalaya from Tileli area, Mandi district, H.P.: implication for stratigraphy and uranium mineralization

    International Nuclear Information System (INIS)

    Pandey, Pradeep; Chabbra, Jyotsana; Joshi, G.B.; Parihar, P.S.

    2014-01-01

    Presence of Early Tertiary pyroclastic material (tephra) has been documented petrographically, for the first time, in the Mandi-Bilaspur Sector from Tileli area, Dharamsala basin of Himachal Pradesh. The tephra is reported from the red shale, identified as tuffaceous siltstone belonging to lower Dharamsala Formation that lies above the uraniferous sandstone body and occurs as thin layers of over 300m along the strike, close to the contact of lower and upper Dharamsala formations. The tuffaceous material shows crude but preferred orientation of minerals like biotite, muscovite, chlorite, clay, hematite and specularite. Various features indicating presence of tephra are, glass shards altered to clay but retaining 'U' shaped outline, spindle-shaped hematite with preferred orientation, spherical to sub-spherical clay and altered Fe oxide rich balls, clay groundmass with flow pattern, flaky minerals in association with clast depicting asymmetrical ramp structure. A zone of approximately 300 m length containing tuffaceous material has been established at Tileli overlying the uraniferous sandstone body. Identification of tephra at Tileli has significant implications as it enabled in demarcating the boundary between the upper and lower Dharamsala formations in central part of the basin in Bilaspur-Mandi Sector of HP Himalaya and also in guiding the uranium exploration programme in the lower Dharamsala Formation. (author)

  11. Impact of super-distal ash fallout on tropical hydrology and landscape: a case study from the YTT deposits of the Perak river, Malaysia

    Science.gov (United States)

    Gatti, E.; Saidin, M.; Gibbard, P.; Oppenheimer, C.

    2011-12-01

    The Younger Toba Tuff eruption, approximately 73 ka ago, is the largest known for the Quaternary and its climate, environmental and human consequences are keenly debated (Oppenheimer, 2011).While the distribution (Rose and Chesner, 1987; Rose and Chesner, 1990; Chesner et al., 1991; Schulz et al., 2002; Von Rad et al., 2002) , geochemical properties (Shane et al., 1995; Westgate et al., 1998) and volcanic significance (Rampino and Self, 1982; Rampino and Self, 1993; Rampino and Ambrose, 2000; Oppenheimer, 2002; Mason et al., 2004)of the YTT have been widely studied, few attention has been given to the significance of the distal volcanic ash deposits within their receiving basin context. Although several studies exist on the impact of pyroclastic flows on proximal rivers and lakes (Collins and Dunne, 1986; Thompson et al., 1986; Hayes et al., 2002; Németh and Cronin, 2007), only few address the issues of the dynamic of preservation of super-distal fine ash deposits in rivers (also due to the lack of direct data on super-eruptions). It has also been demonstrated that models of the styles and timing of distal volcanoclastic re-sedimentation are more complicated than those developed for proximal settings of stratovolcanoes (Kataoka et al., 2009). We present an analysis of the taphonomy (intended as accumulation and preservation) of distal volcanic ash in fluvial and lacustrian contexts in newly discovered Toungest Toba Tuff sites in the Lenggong valley, western Peninsular Malaysia. The paper aims to characterise the nature of distal tephras in fluvial environments towards a stratigraphic distinction between primary ash and secondary ash, characterisation of the pre-ash fall receiving environment in term of fluvial dynamic and landscape morphology, and assessment of the time of recovery.

  12. Falls following discharge after an in-hospital fall

    Directory of Open Access Journals (Sweden)

    Kessler Lori A

    2009-12-01

    Full Text Available Abstract Background Falls are among the most common adverse events reported in hospitalized patients. While there is a growing body of literature on fall prevention in the hospital, the data examining the fall rate and risk factors for falls in the immediate post-hospitalization period has not been well described. The objectives of the present study were to determine the fall rate of in-hospital fallers at home and to explore the risk factors for falls during the immediate post-hospitalization period. Methods We identified patients who sustained a fall on one of 16 medical/surgical nursing units during an inpatient admission to an urban community teaching hospital. After discharge, falls were ascertained using weekly telephone surveillance for 4 weeks post-discharge. Patients were followed until death, loss to follow up or end of study (four weeks. Time spent rehospitalized or institutionalized was censored in rate calculations. Results Of 95 hospitalized patients who fell during recruitment, 65 (68% met inclusion criteria and agreed to participate. These subjects contributed 1498 person-days to the study (mean duration of follow-up = 23 days. Seventy-five percent were African-American and 43% were women. Sixteen patients (25% had multiple falls during hospitalization and 23 patients (35% suffered a fall-related injury during hospitalization. Nineteen patients (29% experienced 38 falls at their homes, yielding a fall rate of 25.4/1,000 person-days (95% CI: 17.3-33.4. Twenty-three patients (35% were readmitted and 3(5% died. One patient experienced a hip fracture. In exploratory univariate analysis, persons who were likely to fall at home were those who sustained multiple falls in the hospital (p = 0.008. Conclusion Patients who fall during hospitalization, especially on more than one occasion, are at high risk for falling at home following hospital discharge. Interventions to reduce falls would be appropriate to test in this high-risk population.

  13. Automatized near-real-time short-term Probabilistic Volcanic Hazard Assessment of tephra dispersion before eruptions: BET_VHst for Vesuvius and Campi Flegrei during recent exercises

    Science.gov (United States)

    Selva, Jacopo; Costa, Antonio; Sandri, Laura; Rouwet, Dmtri; Tonini, Roberto; Macedonio, Giovanni; Marzocchi, Warner

    2015-04-01

    Probabilistic Volcanic Hazard Assessment (PVHA) represents the most complete scientific contribution for planning rational strategies aimed at mitigating the risk posed by volcanic activity at different time scales. The definition of the space-time window for PVHA is related to the kind of risk mitigation actions that are under consideration. Short temporal intervals (days to weeks) are important for short-term risk mitigation actions like the evacuation of a volcanic area. During volcanic unrest episodes or eruptions, it is of primary importance to produce short-term tephra fallout forecast, and frequently update it to account for the rapidly evolving situation. This information is obviously crucial for crisis management, since tephra may heavily affect building stability, public health, transportations and evacuation routes (airports, trains, road traffic) and lifelines (electric power supply). In this study, we propose a methodology named BET_VHst (Selva et al. 2014) for short-term PVHA of volcanic tephra dispersal based on automatic interpretation of measures from the monitoring system and physical models of tephra dispersal from all possible vent positions and eruptive sizes based on frequently updated meteorological forecasts. The large uncertainty at all the steps required for the analysis, both aleatory and epistemic, is treated by means of Bayesian inference and statistical mixing of long- and short-term analyses. The BET_VHst model is here presented through its implementation during two exercises organized for volcanoes in the Neapolitan area: MESIMEX for Mt. Vesuvius, and VUELCO for Campi Flegrei. References Selva J., Costa A., Sandri L., Macedonio G., Marzocchi W. (2014) Probabilistic short-term volcanic hazard in phases of unrest: a case study for tephra fallout, J. Geophys. Res., 119, doi: 10.1002/2014JB011252

  14. Diagnosis and Tests: Evaluating a Fall or Risk of Falling

    Science.gov (United States)

    ... as a physical therapist, who can evaluate your fall risk. If your healthcare provider concludes that you are ... to check for things that can impact your fall risk, such as electrolyte balance and the possibility of ...

  15. Falling and fall risk in adult patients with severe haemophilia.

    Science.gov (United States)

    Rehm, Hanna; Schmolders, Jan; Koob, Sebastian; Bornemann, Rahel; Goldmann, Georg; Oldenburg, Johannes; Pennekamp, Peter; Strauss, Andreas C

    2017-05-10

    The objective of this study was to define fall rates and to identify possible fall risk factors in adult patients with severe haemophilia. 147 patients with severe haemophilia A and B were evaluated using a standardized test battery consisting of demographic, medical and clinical variables and fall evaluation. 41 (27.9 %) patients reported a fall in the past 12 months, 22 (53.7 %) of them more than once. Young age, subjective gait insecurity and a higher number of artificial joints seem to be risk factors for falling. Falls seem to be a common phenomenon in patients with severe haemophilia. Fall risk screening and fall prevention should be implemented into daily practice.

  16. The clinical practice guideline for falls and fall risk

    OpenAIRE

    Vance, Jacqueline

    2011-01-01

    Falling is a significant cause of injury and death in frail older adults. Residents in long-term care (LTC) facilities fall for a variety of reasons and are more likely to endure injuries after a fall than those in the community The American Medical Directors Association (AMDA) Clinical Practice Guideline is written to give LTC staff an understanding of risk factors for falls and provide guidance for a systematic approach to patient assessment and selection of appropriate interventions. It is...

  17. American West Tephras – Geomagnetic polarity events redefined through calibration of radio-isotopic and astronomical time

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael

    calibration. Although this geomagnetic event is not part of the most recent geologic timescale, refined ages on short-lived excursions could hold importance to understanding time scales for the wavering nature of Earth’s magnetic field. We propose a new 40Ar/39Ar age for the Quaternary mineral dating standard......The foundation of the EARTHTIME/GTSnext initiative seeks to construct an internally consistent geologic timescale based on astronomical and radio-isotopic geochronology. American west tephras offer a prime opportunity to integrate these two independent timescales with the geomagnetic timescale....... Using an astronomically calibrated age for the monitor mineral Fish Canyon sanidine (FCs;28.201 ± 0.046 Ma, Kuiper, et al., 2008), ages of Pleistocene geomagnetic polarity events are reexamined. Of particular interest, the Quaternary mineral dating standard Alder Creek sandine (ACs) is the type locality...

  18. Urban fall traps

    Directory of Open Access Journals (Sweden)

    Vera Lucia de Almeida Valsecchi

    2007-06-01

    Full Text Available Objectives: To evaluate the repercussion of falls in the elderly peoplewho live in the city of São Paulo and address - though synthetically- some questions regarding the city and its relation to aging and thequality of life of the elderly. Methods: This is a qualitative study. As fordata collection, “in-depth individual interviews” were applied. Selectionof subjects was guided by a procedure named as “network”. Results:Ten interviews were performed, nine with elderly individuals who werevictims of falls and one with a public authority representative. Dataresulting from interviews confirmed that significant changes occurin live of the elderly, who are victims of what has been called “urbantraps”, and that, by extrapolating mobility and dependence contexts,invade feelings, emotions and desires. The inappropriate environmentprovided by the city of São Paulo is confirmed by absence of adequateurban planning and lack of commitment of public authorities. It alsorevealed that the particular way of being old and living an elderlylife, in addition to right to citizenship, is reflected by major or lesserdifficulties imposed to the elderly to fight for their rights and have theirpublic space respected. Conclusion: The city of São Paulo is not anideal locus for an older person to live in. To the traps that are found inpublic places one can add those that are found in private places andthat contribute to the hard experience of falls among the elderly, anexperience that is sometimes fatal. In Brazil, the attention is basicallyfocused on the consequences of falls and not on prevention, by meansof urban planning that should meet the needs of the most vulnerablegroups - the physically disabled and the elderly.

  19. Fall prevention in older persons

    African Journals Online (AJOL)

    weak muscles, poor vision, psychotropic medications ... with increased risk of falls.[3]. Building on the .... [8] First eye cataract surgery has ... of users of bifocals in which half the subjects .... falls of providing single lens distance vision glasses.

  20. Fall prevention walker during rehabilitation

    Science.gov (United States)

    Tee, Kian Sek; E, Chun Zhi; Saim, Hashim; Zakaria, Wan Nurshazwani Wan; Khialdin, Safinaz Binti Mohd; Isa, Hazlita; Awad, M. I.; Soon, Chin Fhong

    2017-09-01

    This paper proposes on the design of a walker for the prevention of falling among elderlies or patients during rehabilitation whenever they use a walker to assist them. Fall happens due to impaired balance or gait problem. The assistive device is designed by applying stability concept and an accelerometric fall detection system is included. The accelerometric fall detection system acts as an alerting device that acquires body accelerometric data and detect fall. Recorded accelerometric data could be useful for further assessment. Structural strength of the walker was verified via iterations of simulation using finite element analysis, before being fabricated. Experiments were conducted to identify the fall patterns using accelerometric data. The design process and detection of fall pattern demonstrates the design of a walker that could support the user without fail and alerts the helper, thus salvaging the users from injuries due to fall and unattended situation.

  1. Preventing Falls and Related Fractures

    Science.gov (United States)

    ... slowed reflexes. Drinking alcoholic beverages also increases the risk of falling. Alcohol slows reflexes and response time; causes dizziness, sleepiness, or lightheadedness; alters balance; and encourages risky behaviors that can lead to falls. The Force and Direction of a Fall The ...

  2. Childhood Falls With Occipital Impacts

    NARCIS (Netherlands)

    Atkinson, Norrell; van Rijn, Rick R.; Starling, Suzanne P.

    2017-01-01

    Falls are commonly reported in children who present with both accidental and inflicted brain injuries. Short falls rarely result in serious or life-threatening injuries. Our purpose is to describe a series of cases of short falls with occipital impact leading to subdural hemorrhage (SDH). We present

  3. The falls and the fear of falling among elderly institutionalized

    Directory of Open Access Journals (Sweden)

    Patrícia Almeida

    2013-06-01

    Full Text Available In the present study it is intended to characterize the history of falls and to evaluate the fear to fall in aged institutionalized. The sample is composed for 113 institutionalized aged people, 32 men and 81 women with a average 82,96 ± 7,03 age of years. The data had been collected by means of a questionnaire and statistical analyzed (descriptive statistics, parametric tests - Test T and Anova - Test U-Mann Whitney, and Test of Kruskal-Wallis – and the Test of Tukey. The results point in the direction of that the women present a bigger number of falls (24.8% and greater fear to fall (Med=55. The falls had occurred in its majority in the context of the room of the institutions. It was verified that people who had at least a fall experience present greater fear to fall comparatively (Med=55 with that they had not the same had no incident of fall in period of time (Med=77. Our results come to strengthen the hypothesis of the changeable sex to be able to be considered a factor of fall risk. Aged that they present a history of falls seems to be more vulnerable to develop the fear to fall.

  4. Mitigating fall risk: A community fall reduction program.

    Science.gov (United States)

    Reinoso, Humberto; McCaffrey, Ruth G; Taylor, David W M

    One fourth of all American's over 65 years of age fall each year. Falls are a common and often devastating event that can pose a serious health risk for older adults. Healthcare providers are often unable to spend the time required to assist older adults with fall risk issues. Without a team approach to fall prevention the system remains focused on fragmented levels of health promotion and risk prevention. The specific aim of this project was to engage older adults from the community in a fall risk assessment program, using the Stopping Elderly Accidents, Deaths & Injuries (STEADI) program, and provide feedback on individual participants' risks that participants could share with their primary care physician. Older adults who attended the risk screening were taking medications that are known to increase falls. They mentioned that their health care providers do not screen for falls and appreciated a community based screening. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. 1990 Fall Meeting Report

    Science.gov (United States)

    Chapman, David S.

    The AGU 1990 Fall Meeting, held in San Francisco December 3-7, continued the steady growth trend for the western meeting set over the last decade. About 5200 members registered for the meeting and 3836 papers were given. The scientific kickoff to the meeting was provided by a Union session on initial results of the current Magellan mission to Venus. The mission was also the focus of a public lecture and short film on highlights of the mission and an extensive Union poster session.

  6. Falls and cerebellar ataxia

    Directory of Open Access Journals (Sweden)

    I. V. Damulin

    2015-01-01

    Full Text Available The paper considers the main causes of falls. Whatever their cause is, falls may lead to severe maladjustment in everyday life. In nearly 1 out of 10 cases, they are accompanied by severe injuries, including fractures (most commonly those of the proximal femur and humerus, hands, pelvic bones, and vertebrae, subdural hematoma, and severe soft tissue and head injuries. This process is emphasized to be multifactorial. Particular emphasis is laid on the involvement of the cerebellum and its associations, which may be accompanied by falls. This is clinically manifested mainly by gait disorders. Walking is a result of an interaction of three related functions (locomotion, maintenance of balance and adaptive reactions. In addition to synergies related to locomotion and balance maintenance, standing at rest and walking are influenced bythe following factors: postural and environmental information (proprioceptive, vestibular, and visual, the capacity to interpret and integrate this information, the ability of the musculoskeletal system to make movements, and the capability to optimally modulate these movements in view of the specific situation and the ability to choose and adapt synergy in terms of external factors and the capacities and purposes of an individual. The clinical signs of damage to the cerebellum and its associations are considered in detail. These structures are emphasized to be involved not only in movements, but also in cognitive functions. The major symptoms that permit cerebellar dysfunction to be diagnosed are given. Symptoms in cerebellar injuries are generally most pronounced when suddenly changing the direction of movements or attempting to start walking immediately after a dramatic rise. The magnitude of ataxia also increases in a patient who tries to decrease the step size. Falling tendencies or bending to one side (in other symptoms characteristic of cerebellar diseases suggest injury of the corresponding

  7. Falling Liquid Films

    CERN Document Server

    Kalliadasis, S; Scheid, B

    2012-01-01

    This research monograph gives a detailed review of the state-of-the-art theoretical methodologies for the analysis of dissipative wave dynamics and pattern formation on the surface of a film falling down a planar, inclined substrate. This prototype is an open-flow hydrodynamic instability representing an excellent paradigm for the study of complexity in active nonlinear media with energy supply, dissipation and dispersion. Whenever possible, the link between theory and experiments is illustrated and the development of order-of-magnitude estimates and scaling arguments is used to facilitate the

  8. New horizons in fall prevention.

    Science.gov (United States)

    Lord, Stephen R; Close, Jacqueline C T

    2018-04-25

    Falls pose a major threat to the well-being and quality of life of older people. Falls can result in fractures and other injuries, disability and fear and can trigger a decline in physical function and loss of autonomy. This article synthesises recent published findings on fall risk and mobility assessments and fall prevention interventions and considers how this field of research may evolve in the future. Fall risk topics include the utility of remote monitoring using wearable sensors and recent work investigating brain activation and gait adaptability. New approaches for exercise for fall prevention including dual-task training, cognitive-motor training with exergames and reactive step training are discussed. Additional fall prevention strategies considered include the prevention of falls in older people with dementia and Parkinson's disease, drugs for fall prevention and safe flooring for preventing fall-related injuries. The review discusses how these new initiatives and technologies have potential for effective fall prevention and improved quality of life. It concludes by emphasising the need for a continued focus on translation of evidence into practice including robust effectiveness evaluations of so that resources can be appropriately targeted into the future.

  9. Phreatomagmatic eruptive and depositional processes during the 1949 eruption on La Palma (Canary Islands)

    Science.gov (United States)

    White, James D. L.; Schmincke, Hans-Ulrich

    1999-12-01

    In 1949, a 5-week-long magmatic and phreatomagmatic eruption took place along the active volcanic ridge of La Palma (Canary Islands). Two vents, Duraznero and Hoyo Negro, produced significant pyroclastic deposits. The eruption began from Duraznero vent, which produced a series of deposits with an upward decrease in accidental fragments and increase in fluidal ash and spatter, together inferred to indicate decreasing phreatomagmatic interaction. Hoyo Negro erupted over a 2-week period, producing a variety of pyroclastic density currents and ballistic blocks and bombs. Hoyo Negro erupted within and modified an older crater having high walls on the northern to southeastern edges. Southwestern to western margins of the crater lay 50 to 100 m lower. Strongly contrasting deposits in the different sectors (N-SE vs. SW-W) were formed as a result of interaction between topography, weak eruptive columns and stratified pyroclastic density currents. Tephra ring deposits are thicker and coarser-grained than upper rim deposits formed along the higher edges of the crater, and beyond the crater margin, valley-confined deposits are thicker than more thinly bedded mantling deposits on higher topography. These differences indicate that the impact zone for the bulk of the collapsing, tephra-laden column lay within the crater and that the high crater walls inhibited escape of pyroclastic density currents to the north and east. The impact zone lay outside the low SW-W rims, however, thus allowing stratified pyroclastic density currents to move freely away from the crater in those directions, depositing thin sections (<30 cm) of well-bedded ash (mantling deposits) on ridges and thicker sections (1-3 m) of structureless ash beds in valleys and small basins. Such segregation of dense pyroclastic currents from more dilute ones at the crater wall is likely to be common for small eruptions from pre-existing craters and is an important factor to be taken into account in volcanic hazards

  10. [Can falls be prevented?].

    Science.gov (United States)

    Dubousset, Jean

    2014-06-01

    Most recommendations and measures intended to prevent falls focus on the elderly (see HAS guideline of April 2009) but, in our opinion, this isfar too late: prevention must begin much earlier, not only by identifying persons at risk, but also by providing personalized lifestyle advice adapted to each individual's biomechanical, somatic, neurological and biological characteristics. The first preventive measure is to identify a possible deterioration of balance, starting with a physical examination at the age of 45 and repeated regularly throughout life. Extrinsic preventive measures focusing on the domestic and external environments are clearly necessary. But what is most important is to detect and, if necessary, correct any degradation of intrinsic (intracorporeal or somatic) factors starting at the age of 45 years; these include vision, vestibular function and balance, proprioception, and psychological and neurological status. Chronic illnesses and their treatments must also be taken into account: treatment must be limited to indispensable drugs; sedative psychotropics must be avoided if possible; and polymedication must be tightly controlled, as it is a major risk factor for falls. Prevention also requires a diet sufficiently rich in protein, calcium and vitamin D3 (to prevent osteoporosis), and regular daily exercise adapted to the individual, if possible associated with a simultaneous cognitive task. The last key point is the absolute need for thorough functional rehabilitation after any accidental or medical trauma, regardless of age, with the aim of restoring functional status to that existing prior to the accident.

  11. Issues in Geriatric Care: Falls.

    Science.gov (United States)

    Patel, Dipesh; Ackermann, Richard J

    2018-05-01

    One in three older adults falls each year. There are approximately 2.5 million falls among older adults treated in emergency departments. Falls account for 87% of all fractures in this age group. The biggest risk factor for falling is a history of falls. Other risk factors include frailty, sedative and anticholinergic drugs, polypharmacy, and a variety of medical conditions. Current recommendations are that all patients age 65 years and older should be asked about falls each year. Patients also can be screened for fall risk with a variety of approaches including questionnaires and the Timed Up & Go test. For patients who have fallen or are at risk, care should focus on correcting reversible home environmental factors that predispose to falls, minimizing the use of drugs with sedating properties, addressing vision conditions, recommending physical exercise (including balance, strength, and gait training), and managing postural hypotension as well as foot conditions and footwear. In addition, vitamin D and calcium supplementation should be considered. For patients needing anticoagulation for medical reasons, an assessment must balance fall risk (and thus bleeding from a fall) versus the risk of discontinuing anticoagulation (eg, sustaining an embolic stroke from atrial fibrillation). Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  12. Correlation of tephra layers by trace elements abundances in glass shards

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, Takaaki

    1988-10-01

    For identifying volcanic ash layer, a method was explained by analyzing minor elements contained in glassy material of volcanic ash. Based upon the understanding that glassy material in volcanic ash was formed by the quenching of magma and that composition of it reflected the composition of magma at the time of deposition, identification of volcanic ash layer was conducted by applying such consideration that minor elements were concentrated in the magma during the deposition process and that distribution coefficient was characteristic of every minor element. For the analysis, apparatus of irradiated neutron was applied. As the result of analysis, variation of the data was approximately 5% among the ashes belong to the same volcano. distribution map of volcanic ash in Japan was prepared by using the result. By this, it was understood that the ashes obtained from the volcanos in the middle part of Japan were different from other but those from Kyushu district were mostly identical among them. For further study of volcano, necessity of such analysis of volcanic ash in the sea bottom mud was explained. 3 references, 2 figures, 1 table.

  13. Tsunami deposits

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    The NSC (the Nuclear Safety Commission of Japan) demand to survey on tsunami deposits by use of various technical methods (Dec. 2011), because tsunami deposits have useful information on tsunami activity, tsunami source etc. However, there are no guidelines on tsunami deposit survey in JAPAN. In order to prepare the guideline of tsunami deposits survey and evaluation and to develop the method of tsunami source estimation on the basis of tsunami deposits, JNES carried out the following issues; (1) organizing information of paleoseismological record and tsunami deposit by literature research, (2) field survey on tsunami deposit, and (3) designing the analysis code of sediment transport due to tsunami. As to (1), we organize the information gained about tsunami deposits in the database. As to (2), we consolidate methods for surveying and identifying tsunami deposits in the lake based on results of the field survey in Fukui Pref., carried out by JNES. In addition, as to (3), we design the experimental instrument for hydraulic experiment on sediment transport and sedimentation due to tsunamis. These results are reflected in the guideline on the tsunami deposits survey and evaluation. (author)

  14. Tsunami deposits

    International Nuclear Information System (INIS)

    2013-01-01

    The NSC (the Nuclear Safety Commission of Japan) demand to survey on tsunami deposits by use of various technical methods (Dec. 2011), because tsunami deposits have useful information on tsunami activity, tsunami source etc. However, there are no guidelines on tsunami deposit survey in JAPAN. In order to prepare the guideline of tsunami deposits survey and evaluation and to develop the method of tsunami source estimation on the basis of tsunami deposits, JNES carried out the following issues; (1) organizing information of paleoseismological record and tsunami deposit by literature research, (2) field survey on tsunami deposit, and (3) designing the analysis code of sediment transport due to tsunami. As to (1), we organize the information gained about tsunami deposits in the database. As to (2), we consolidate methods for surveying and identifying tsunami deposits in the lake based on results of the field survey in Fukui Pref., carried out by JNES. In addition, as to (3), we design the experimental instrument for hydraulic experiment on sediment transport and sedimentation due to tsunamis. These results are reflected in the guideline on the tsunami deposits survey and evaluation. (author)

  15. Surface Ocean Radiocarbon Reservoir Ages From Land-Sea Tephra Correlation Constrains Deglacial Chronology and Ocean Circulation in the Southeast Bering Sea

    Science.gov (United States)

    Cook, M. S.; Miller, R.; White-Nockleby, C.; Chapman, A.; Mix, A. C.

    2017-12-01

    Radiocarbon estimates of the past ocean are valuable because unlike passive tracers, radiocarbon has the potential to trace both the distribution and rate of transport of water masses. Most studies using paired radiocarbon measurements on planktonic and benthic foraminifera assume that the surface reservoir age was constant at the preindustrial value, which if incorrect, can strongly bias radiocarbon reconstructions. The subarctic Pacific is ringed by volcanic arcs, and there is great potential to use tephrochronology as a stratigraphic tool in sediments from the last glacial and deglaciation, and assign calendar ages to the marine sediment without relying on calibrated planktonic radiocarbon ages. In this study, we use major and trace element analysis of volcanic glass to match tephras between radiocarbon-dated lake cores from Sanak Island in the eastern Aleutians to marine cores from Umnak Plateau in the southeast Bering Sea. There are numerous thin tephras preserved in laminated sediments from the Bolling-Allerod and early Holocene in marine cores from depths (1000-1500 m) within the modern oxygen minimum zone. We find that trace elements are crucial in distinguishing tephras from individual eruptions. Our preliminary radiocarbon measurements suggest that the benthic-atmosphere radiocarbon differences and marine surface reservoir ages in the Bolling-Allerod are similar to pre-industrial values, supporting previously published radiocarbon reconstructions from the region.

  16. Fall prevention in nursing homes

    DEFF Research Database (Denmark)

    Andresen, Mette; Hauge, Johnny

    2014-01-01

    that the number of hospitalization after a fall injury will become an even greater task for the Danish hospitals, The aim of the study was to show if there is a relationship between physically frail elderly nursing home resident’s subjective evaluation of fall-risk and an objective evaluation of their balance....... Further, to suggest tools for fall prevention in nursing home settings on the basis of the results of this study and the literature. A quantitative method inspired by the survey method was used to give an overview of fall patterns, subjective and objective evaluations of fallrisk. Participants were 16...... physically frail elderly nursing home residents from three different nursing homes. Measures: a small staff-questionnaire about incidences and places where the participants had falling-episodes during a 12 month period, The Falls Effi cacy Scale Swedish version (FES(S)) and Berg Balance Scale (BBS) Results...

  17. Investigation of surface deposition pertaining to the calculation of the deposition of aerosols released in core-meltdown accidents in power reactors

    International Nuclear Information System (INIS)

    Roed, J.

    1981-10-01

    Deposition of fall-out particles of cesium-137 on vertical building surfaces has been measured. The deposition is combined with the corresponding concentration in air of fall-out particles to give the dry deposition velocity. The dry deposition velocity on plane collectors like building surfaces, plane bare soil, roads, etc. is compared to the velocity on rough surfaces like grass, clover, etc. This is done on the basis of our own measurements and the relevant literature. (author)

  18. A piece of paper falling faster than free fall

    International Nuclear Information System (INIS)

    Vera, F; Rivera, R

    2011-01-01

    We report a simple experiment that clearly demonstrates a common error in the explanation of the classic experiment where a small piece of paper is put over a book and the system is let fall. This classic demonstration is used in introductory physics courses to show that after eliminating the friction force with the air, the piece of paper falls with acceleration g. To test if the paper falls behind the book in a nearly free fall motion or if it is dragged by the book, we designed a version of this experiment that includes a ball and a piece of paper over a book that is forced to fall using elastic cords. We recorded a video of our experiment using a high-speed video camera at 300 frames per second that shows that the book and the paper fall faster than the ball, which falls well behind the book with an acceleration approximately equal to g. Our experiment shows that the piece of paper is dragged behind the book and therefore the paper and book demonstration should not be used to show that all objects fall with acceleration g independently of their mass.

  19. A piece of paper falling faster than free fall

    Energy Technology Data Exchange (ETDEWEB)

    Vera, F; Rivera, R, E-mail: fvera@ucv.cl [Instituto de Fisica, Pontificia Universidad Catolica de ValparaIso, Av. Universidad 330, Curauma, ValparaIso (Chile)

    2011-09-15

    We report a simple experiment that clearly demonstrates a common error in the explanation of the classic experiment where a small piece of paper is put over a book and the system is let fall. This classic demonstration is used in introductory physics courses to show that after eliminating the friction force with the air, the piece of paper falls with acceleration g. To test if the paper falls behind the book in a nearly free fall motion or if it is dragged by the book, we designed a version of this experiment that includes a ball and a piece of paper over a book that is forced to fall using elastic cords. We recorded a video of our experiment using a high-speed video camera at 300 frames per second that shows that the book and the paper fall faster than the ball, which falls well behind the book with an acceleration approximately equal to g. Our experiment shows that the piece of paper is dragged behind the book and therefore the paper and book demonstration should not be used to show that all objects fall with acceleration g independently of their mass.

  20. Updates to concepts on phreatomagmatic maar-diatremes and their pyroclastic deposits

    Science.gov (United States)

    Valentine, Greg A.; White, James D. L.; Ross, Pierre-Simon; Graettinger, Alison H.; Sonder, Ingo

    2017-08-01

    Recent work is changing our understanding of phreatomagmatic maar-diatreme eruptions and resulting deposits. In previous models, explosions were often inferred to take place only at the base of a diatreme, with progressive downward migration due to a cone of depression in the host aquifer. However, diatremes themselves contain much water that is heterogeneously distributed, and field evidence supports the existence of explosion sites at many vertical and lateral locations within them. Crater sizes have been used to estimate explosion energies, but this only works for single-explosion craters where the depth of explosion is independently known, and has limited value for multi-explosion maar-diatremes. Deep-seated lithic clasts in tephra ring beds have been taken to indicate the depth of the explosion that produced that bed. However, only relatively shallow explosions actually vent to the surface, and deep-seated lithics are gradually brought to shallow depths through step-wise mixing of multiple subsurface explosions. Grain-size of tephra-ring deposits is often inferred to indicate fragmentation efficiency. However, other factors strongly influence deposit grain size, including the scaled depth of an explosion and the interaction of an erupting jet with topography around a vent (e.g., crater), along with long recognized effects of mechanical properties of host rocks and recycling within the vent/diatreme. These insights provide a foundation for future research into this important volcano type.

  1. Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE

    Science.gov (United States)

    Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.

    2012-01-01

    The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanak

  2. Keanakākoʻi Tephra produced by 300 years of explosive eruptions following collapse of Kīlauea's caldera in about 1500 CE

    Science.gov (United States)

    Swanson, Donald A.; Rose, Timothy R.; Fiske, Richard S.; McGeehin, John P.

    2012-01-01

    The Keanakākoʻi Tephra at Kīlauea Volcano has previously been interpreted by some as the product of a caldera-forming eruption in 1790 CE. Our study, however, finds stratigraphic and 14C evidence that the tephra instead results from numerous eruptions throughout a 300-year period between about 1500 and 1800. The stratigraphic evidence includes: (1) as many as six pure lithic ash beds interleaved in sand dunes made of earlier Keanakākoʻi vitric ash, (2) three lava flows from Kīlauea and Mauna Loa interbedded with the tephra, (3) buried syneruptive cultural structures, (4) numerous intraformational water-cut gullies, and (5) abundant organic layers rich in charcoal within the tephra section. Interpretation of 97 new accelerator mass spectrometry (AMS) 14C ages and 4 previous conventional ages suggests that explosive eruptions began in 1470–1510 CE, and that explosive activity continued episodically until the early 1800s, probably with two periods of quiescence lasting several decades. Kīlauea's caldera, rather than forming in 1790, predates the first eruption of the Keanakākoʻi and collapsed in 1470–1510, immediately following, and perhaps causing, the end of the 60-year-long, 4–6 km3 ʻAilāʻau eruption from the east side of Kīlauea's summit area. The caldera was several hundred meters deep when the Keanakākoʻi began erupting, consistent with oral tradition, and probably had a volume of 4–6 km3. The caldera formed by collapse, but no eruption of lava coincided with its formation. A large volume of magma may have quickly drained from the summit reservoir and intruded into the east rift zone, perhaps in response to a major south-flank slip event, leading to summit collapse. Alternatively, magma may have slowly drained from the reservoir during the prolonged ʻAilāʻau eruption, causing episodic collapses before the final, largest downdrop took place. Two prolonged periods of episodic explosive eruptions are known at Kīlauea, the Keanak

  3. Exogenous deposits

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Exogenous deposits forming as a result of complex exogenous processes, passed under the influence of outside forces on the Earth surface. To them relate physical and chemical weathering, decomposition and decay of mineral masses, redistribution and transportation of material, forming and deposit of new minerals and ores steady on the earth surface conditions

  4. Preventing Falls in Older Persons.

    Science.gov (United States)

    Moncada, Lainie Van Voast; Mire, L Glen

    2017-08-15

    The American Geriatrics Society and British Geriatrics Society recommend that all adults older than 65 years be screened annually for a history of falls or balance impairment. The U.S. Preventive Services Task Force and American Academy of Family Physicians recommend exercise or physical therapy and vitamin D supplementation to prevent falls in community-dwelling older adults who are at increased risk of falls. Although the U.S. Preventive Services Task Force and American Academy of Family Physicians do not recommend routine multifactorial intervention to prevent falls in all community-dwelling older adults, they state that it may be appropriate in individual cases. The Centers for Disease Control and Prevention developed an algorithm to aid in the implementation of the American Geriatrics Society/British Geriatrics Society guideline. The algorithm suggests assessment and multifactorial intervention for those who have had two or more falls or one fall-related injury. Multifactorial interventions should include exercise, particularly balance, strength, and gait training; vitamin D supplementation with or without calcium; management of medications, especially psychoactive medications; home environment modification; and management of postural hypotension, vision problems, foot problems, and footwear. These interventions effectively decrease falls in the community, hospital, and nursing home settings. Fall prevention is reimbursed as part of the Medicare Annual Wellness Visit.

  5. Fall prevention in the elderly.

    Science.gov (United States)

    Ungar, Andrea; Rafanelli, Martina; Iacomelli, Iacopo; Brunetti, Maria Angela; Ceccofiglio, Alice; Tesi, Francesca; Marchionni, Niccolò

    2013-05-01

    Falls are frequent in the elderly and affect mortality, morbidity, loss of functional capacity and institutionalization. In the older patient the incidence of falls can sometimes be underestimated, even in the absence of a clear cognitive impairment, because it is often difficult to reconstruct the dynamics. It is quite common that forms due to syncope are associated with retrograde amnesia and in 40 to 60% of the cases falls happen in the absence of witnesses. The pathogenesis of falls is often multifactorial, due to physiological age-related changes or more properly pathological factors, or due to the environment. The identification of risk factors is essential in the planning of preventive measures. Syncope is one of major causes of falls. About 20% of cardiovascular syncope in patients older than 70 appears as a fall and more than 20% of older people with Carotid Sinus Syndrome complain of falls as well as syncope. These data clearly state that older patients with history of falls should undergo a cardiovascular and neuroautonomic assessment besides the survey of other risk factors. Multifactorial assessment requires a synergy of various specialists. The geriatrician coordinates the multidisciplinary intervention in order to make the most effective evaluation of the risk of falling, searching for all predisposing factors, aiming towards a program of prevention. In clear pathological conditions it is possible to enact a specific treatment. Particular attention must indeed be paid to the re-evaluation of drug therapy, with dose adjustments or withdrawal especially for antihypertensive, diuretics and benzodiazepines. The Guidelines of the American Geriatrics Society recommend modification of environmental hazards, training paths, hip protectors and appropriate use of support tools (sticks, walkers), which can be effective elements of a multifactorial intervention program. Balance exercises are also recommended. In conclusion, an initial assessment, supported by a

  6. Geriatric fall-related injuries.

    Science.gov (United States)

    Hefny, Ashraf F; Abbas, Alaa K; Abu-Zidan, Fikri M

    2016-06-01

    Falls are the leading cause of geriatric injury. We aimed to study the anatomical distribution, severity, and outcome of geriatric fall-related injuries in order to give recommendations regarding their prevention. All injured patients with an age ≥ 60 years who were admitted to Al-Ain Hospital or died in the Emergency Department due to falls were prospectively studied over a four year period. We studied 92 patients. Fifty six of them (60.9%) were females. The mean (standard deviation) of age was 72.2 (9.6) years. Seventy three (89%) of all incidents occurred at home. Eighty three patients (90.2%) fell on the same level. The median (range) ISS was 4 (1-16) and the median GCS (range) was 15 (12-15). The lower limb was the most common injured body region (63%). There were no statistical significant differences between males and females regarding age, ISS, and hospital stay (p = 0.85, p = 0.57, and p = 0.35 respectively). The majority of geriatric fall-related injuries were due to fall from the same level at home. Assessment of risk factors for falls including home hazards is essential for prevention of geriatric fall-related injuries.

  7. Exploring Links Between Global Climate and Explosive Arc Volcanism in Tephra-Rich Quaternary Sediments: A Pilot Study from IODP Expedition 350 Site 1437B, Izu Bonin Rear-Arc Region

    Science.gov (United States)

    Corry-Saavedra, K.; Straub, S. M.; Bolge, L.; Schindlbeck, J. C.; Kutterolf, S.; Woodhead, J. D.

    2015-12-01

    Fallout tephra in marine sediment provide an excellent archive of explosive arc volcanism that can be directly related to the other parameters of climate change, such as ice volume data, IRD (ice-rafted debris) input, etc. Current studies are based on 'discrete' tephra beds, which are produced by major eruptions and visible with the naked eye. Yet the more common, but less explosive arc eruptions that are more continuous through time produce 'disperse' tephra, which is concealed by the non-volcanic host sediment and invisible to the eye. The proportion of disperse tephra in marine sediments is known to be significant and may be critical in elucidating potential synchronicity between arc volcanism and glacial cycles. We conducted a pilot study in young sediments of IODP Hole 1437B drilled at 31°47.3911'N and 139°01.5788'E at the rear-arc of the Izu Bonin volcanic arc. By means of δ18O (Vautravers, in revision), eleven climatic cycles are recorded in uppermost 120 meter of carbonate mud that is interspersed by cm-thick tephra fallout layers. We selected six tephra layers, ranging from 0.2 to 1.16 million years in age, and sampled those vertically, starting from carbonate mud below the basal contact throughout the typical gradational top into the carbonate mud above. From each tephra bed, volcanic particles (>125 micrometer) were handpicked. All other samples were powdered and leached in buffered acetic acid and hydroxylamine hydrochloride to remove the carbonate and authigenous fraction, respectively. Major and trace element abundances (except for SiO2) from all samples were determined by ICP-MS and ICP-OES methods. Strong binary mixing trends are revealed between the pure tephra end member, and detrital sediment component. The tephra is derived from the Izu Bonin volcanic front and rear-arc, while the sediment component is presumably transported by ocean surface currents from the East China Sea. Our data show that mixing proportions change systematically with

  8. Cowlitz Falls fish passage

    International Nuclear Information System (INIS)

    1995-09-01

    The upper Cowlitz was once home to native salmon and steelhead. But the combined impacts of overharvest, farming, logging and road building hammered fish runs. And in the 1960s, a pair of hydroelectric dams blocked the migration path of ocean-returning and ocean-going fish. The lower Cowlitz still supports hatchery runs of chinook, coho and steelhead. But some 200 river miles in the upper river basin--much of it prime spawning and rearing habitat--have been virtually cut off from the ocean for over 26 years. Now the idea is to trap-and-haul salmon and steelhead both ways and bypass previously impassable obstacles in the path of anadromous fish. The plan can be summarized, for the sake of explanation, in three steps: (1) trap and haul adult fish--collect ocean-returning adult fish at the lowermost Cowlitz dam, and truck them upstream; (2) reseed--release the ripe adults above the uppermost dam, and let them spawn naturally, at the same time, supplement these runs with hatchery born fry that are reared and imprinted in ponds and net pens in the watershed; (3) trap and haul smolts--collection the new generation of young fish as they arrive at the uppermost Cowlitz dam, truck them past the three dams, and release them to continue their downstream migration to the sea. The critical part of any fish-collection system is the method of fish attraction. Scientists have to find the best combination of attraction system and screens that will guide young fish to the right spot, away from the turbine intakes. In the spring of 1994 a test was made of a prototype system of baffles and slots on the upriver face of the Cowlitz Falls Dam. The prototype worked at 90% efficiency in early tests, and it worked without the kind of expensive screening devices that have been installed on other dams. Now that the success of the attraction system has been verified, Harza engineers and consultants will design and build the appropriate collection part of the system

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

    Science.gov (United States)

    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

  10. Community College Estimated Growth: Fall 2010

    Science.gov (United States)

    Phillippe, Kent; Mullin, Christopher M.

    2011-01-01

    A survey from the American Association of Community Colleges (AACC) found that enrollment growth in fall 2010 slowed its pace at community colleges, increasing 3.2% from the previous year. This contrasts with more dramatic increases in recent years: more than 11% between fall 2008 and fall 2009, and nearly 17% between fall 2007 and fall 2009,…

  11. Rehabilitation after falls and fractures.

    Science.gov (United States)

    Dionyssiotis, Y; Dontas, I A; Economopoulos, D; Lyritis, G P

    2008-01-01

    Falls are one of the most common geriatric problems threatening the independence of older persons. Elderly patients tend to fall more often and have a greater tendency to fracture their bones. Fractures occur particularly in osteoporotic people due to increased bone fragility, resulting in considerable reduction of quality of life, morbidity, and mortality. This article provides information for the rehabilitation of osteoporotic fractures pertaining to the rehabilitation of the fractured patient, based on personal experience and literature. It also outlines a suggested effective and efficient clinical strategy approach for preventing falls in individual patients.

  12. Toward a Last Interglacial Compilation Using a Tephra-based Chronology: a Future Reference For Model-data Comparison

    Science.gov (United States)

    Bazin, L.; Govin, A.; Capron, E.; Nomade, S.; Lemieux-Dudon, B.; Landais, A.

    2017-12-01

    The Last Interglacial (LIG, 129-116 ka) is a key period to decipher the interactions between the different components of the climate system under warmer-than-preindustrial conditions. Modelling the LIG climate is now part of the CMIP6/PMIP4 targeted simulations. As a result, recent efforts have been made to propose surface temperature compilations focusing on the spatio-temporal evolution of the LIG climate, and not only on its peak warmth as previously proposed. However, the major limitation of these compilations remains in the climatic alignment of records (e.g. temperature, foraminiferal δ18O) that is performed to define the sites' chronologies. Such methods prevent the proper discussion of phase relationship between the different sites. Thanks to recent developments of the Bayesian Datice dating tool, we are now able to build coherent multi-archive chronologies with a proper propagation of the associated uncertainties. We make the best use of common tephra layers identified in well-dated continental archives and marine sediment cores of the Mediterranean region to propose a coherent chronological framework for the LIG independent of any climatic assumption. We then extend this precise chronological context to the North Atlantic as a first step toward a global coherent compilation of surface temperature and stable isotope records. Based on this synthesis, we propose guidelines for the interpretation of different proxies measured from different archives that will be compared with climate model parameters. Finally, we present time-slices (e.g. 127 ka) of the preliminary regional synthesis of temperature reconstructions and stable isotopes to serve as reference for future model-data comparison of the up-coming CMIP6/PMIP4 LIG simulations.

  13. Falls: epidemiology, pathophysiology, and relationship to fracture.

    Science.gov (United States)

    Berry, Sarah D; Miller, Ram R

    2008-12-01

    Falls are common in the elderly, and frequently result in injury and disability. Most falls result from an interaction between individual characteristics that increase an individual's propensity to fall and acute mediating risk factors that provide the opportunity to fall. Predisposing risk factors include age-associated changes in strength and balance, comorbidities such as osteoarthritis, visual impairment and dementia, psychotropic medications, and certain types of footwear. Fewer studies have focused on acute precipitating factors, but environmental and situational factors are clearly important to fall risk. Approximately 30% of falls result in an injury that requires medical attention, with fractures occurring in approximately 10%. In addition to the risk factors for falls, the fall descent, fall impact, and bone strength are all important determinants of whether a fall will result in a fracture. In recent years, numerous studies have been directed toward the development of effective fall and fall-related fracture prevention interventions.

  14. Free Falling in Stratified Fluids

    Science.gov (United States)

    Lam, Try; Vincent, Lionel; Kanso, Eva

    2017-11-01

    Leaves falling in air and discs falling in water are examples of unsteady descents due to complex interaction between gravitational and aerodynamic forces. Understanding these descent modes is relevant to many branches of engineering and science such as estimating the behavior of re-entry space vehicles to studying biomechanics of seed dispersion. For regularly shaped objects falling in homogenous fluids, the motion is relatively well understood. However, less is known about how density stratification of the fluid medium affects the falling behavior. Here, we experimentally investigate the descent of discs in both pure water and in stable linearly stratified fluids for Froude numbers Fr 1 and Reynolds numbers Re between 1000 -2000. We found that stable stratification (1) enhances the radial dispersion of the disc at landing, (2) increases the descent time, (3) decreases the inclination (or nutation) angle, and (4) decreases the fluttering amplitude while falling. We conclude by commenting on how the corresponding information can be used as a predictive model for objects free falling in stratified fluids.

  15. Influences of volcanism on coal quality - Examples from the western United States

    International Nuclear Information System (INIS)

    Hildebrand, R.T.; Affolter, R.H.

    1986-01-01

    Several small Tertiary coal deposits in Idaho, Nevada, and Washington formed in fresh-water basins located near active continental (salic) volcanic centers. Metastable glassy material (tephra) ejected during volcanic eruptions was introduced into the coal-forming environment of these basins as ash falls. This tephra contributed to the high ash content of many of the coal beds, formed laterally persistent partings (''tonsteins'') in the coal, and constitutes a large part of the strata enclosing the deposits. In order to study the possible relationships between the presence of tephra and coal quality, chemical data for 65 coal samples from 12 of these deposits were compiled and statistically analyzed. The results indicate that, in addition to the high ash content, coal from Tertiary deposits containing appreciable amounts of tephra generally is enriched in many elements compared to 460 coal samples from 11 deposits of similar ages remote from volcanic activity

  16. Epidemiology of falls in older age.

    Science.gov (United States)

    Peel, Nancye May

    2011-03-01

    Worldwide, falls among older people are a public health concern because of their frequency and adverse consequences in terms of morbidity, mortality, and quality of life, as well as their impact on health system services and costs. This epidemiological review outlines the public health burden of falls and fall-related injuries and the impact of population aging. The magnitude of the problem is described in terms of the classification of falls and measurement of outcomes, including fall incidence rates across settings, sociodemographic determinants, international trends, and costs of falls and fall-related injuries. Finally, public health approaches to minimize falls risk and consequent demand on health care resources are suggested.

  17. Falls and patient safety for older adults.

    Science.gov (United States)

    Aronovitch, Sharon A

    2006-10-01

    The risk of falling increases with age. Falls in the elderly have been found to raise mortality and morbidity rates and are a leading cause of premature admission to long-term care facilities. Attention to known intrinsic and extrinsic factors that predispose to falling is important in community dwelling and institutionalized older adults. New government guidelines for long-term care facilities have helped focus attention on the safety aspect of fall risk and information about the physical and psychological impact of falling is increasing. Implementation of fall prevention protocols, including the use of fall risk assessment tools, may help reduce the incidence of falls and resultant complications.

  18. Fall prevention in the elderly

    Science.gov (United States)

    Ungar, Andrea; Rafanelli, Martina; Iacomelli, Iacopo; Brunetti, Maria Angela; Ceccofiglio, Alice; Tesi, Francesca; Marchionni, Niccolò

    2013-01-01

    Summary Falls are frequent in the elderly and affect mortality, morbidity, loss of functional capacity and institutionalization. In the older patient the incidence of falls can sometimes be underestimated, even in the absence of a clear cognitive impairment, because it is often difficult to reconstruct the dynamics. It is quite common that forms due to syncope are associated with retrograde amnesia and in 40 to 60% of the cases falls happen in the absence of witnesses. The pathogenesis of falls is often multifactorial, due to physiological age-related changes or more properly pathological factors, or due to the environment. The identification of risk factors is essential in the planning of preventive measures. Syncope is one of major causes of falls. About 20% of cardiovascular syncope in patients older than 70 appears as a fall and more than 20% of older people with Carotid Sinus Syndrome complain of falls as well as syncope. These data clearly state that older patients with history of falls should undergo a cardiovascular and neuroautonomic assessment besides the survey of other risk factors. Multifactorial assessment requires a synergy of various specialists. The geriatrician coordinates the multidisciplinary intervention in order to make the most effective evaluation of the risk of falling, searching for all predisposing factors, aiming towards a program of prevention. In clear pathological conditions it is possible to enact a specific treatment. Particular attention must indeed be paid to the re-evaluation of drug therapy, with dose adjustments or withdrawal especially for antihypertensive, diuretics and benzodiazepines. The Guidelines of the American Geriatrics Society recommend modification of environmental hazards, training paths, hip protectors and appropriate use of support tools (sticks, walkers), which can be effective elements of a multifactorial intervention program. Balance exercises are also recommended. In conclusion, an initial assessment

  19. Catching a Falling Star

    Science.gov (United States)

    2004-07-01

    . Comets are another important source of meteoroids and perhaps the most spectacular. After many visits near the Sun, a comet "dirty-snowball" nucleus of ice and dust decays and fragments, leaving a trail of meteoroids along its orbit. Some "meteoroid streams" cross the earth's orbit and when our planet passes through them, some of these particles will enter the atmosphere. The outcome is a meteor shower - the most famous being the "Perseids" in the month of August [2] and the "Leonids" in November. Thus, although meteors are referred to as "shooting" or "falling stars" in many languages, they are of a very different nature. More information The research presented in this paper is published in the journal Meteoritics and Planetary Science, Vol. 39, Nr. 4, p. 1, 2004 ("Spectroscopic anatomy of a meteor trail cross section with the ESO Very Large Telescope", by P. Jenniskens et al.). Notes [1] The team is composed of Peter Jenniskens (SETI Institute, USA), Emmanuël Jehin (ESO), Remi Cabanac (Pontificia Universidad Catolica de Chile), Christophe Laux (Ecole Centrale de Paris, France), and Iain Boyd (University of Michigan, USA). [2] The maximum of the Perseids is expected on August 12 after sunset and should be easily seen.

  20. Falls in Parkinson's disease and Huntington's disease

    NARCIS (Netherlands)

    Grimbergen, Yvette Anna Maria

    2012-01-01

    Falls in Parkinson’s (PD) and Huntington’s disease (HD) are common. 50 % of moderately affected PD patients sustained two or more falls during a prospective follow-up of 6 months. During a 3 month period 40 % of HD patients reported one or more fall. Many falls resulted in minor injuries and 42 % of

  1. A Piece of Paper Falling Faster than Free Fall

    Science.gov (United States)

    Vera, F.; Rivera, R.

    2011-01-01

    We report a simple experiment that clearly demonstrates a common error in the explanation of the classic experiment where a small piece of paper is put over a book and the system is let fall. This classic demonstration is used in introductory physics courses to show that after eliminating the friction force with the air, the piece of paper falls…

  2. Patient centered fall risk awareness perspectives: clinical correlates and fall risk

    Science.gov (United States)

    Verghese, Joe

    2016-01-01

    Background While objective measures to assess risk of falls in older adults have been established; the value of patient self-reports in the context of falls is not known. Objectives To identify clinical correlates of patient centered fall risk awareness, and their validity for predicting falls. Design Prospective cohort study. Setting and Participants 316 non-demented and ambulatory community-dwelling older adults (mean age 78 years, 55% women). Measurements Fall risk awareness was assessed with a two-item questionnaire, which asked participants about overall likelihood and personal risk of falling over the next 12 months. Incident falls were recorded over study follow-up. Results Fifty-three participants (16.8%) responded positively to the first fall risk awareness question about being likely to have a fall in the next 12 months, and 100 (31.6%) reported being at personal risk of falling over the next 12 months. There was only fair correlation (kappa 0.370) between responses on the two questions. Prior falls and depressive symptoms were associated with positive responses on both fall risk awareness questions. Age and other established fall risk factors were not associated with responses on both fall risk awareness questions. The fall risk awareness questionnaire did not predict incident falls or injurious falls. Conclusion Fall risk awareness is low in older adults. While patient centered fall risk awareness is not predictive of falls, subjective risk perceptions should be considered when designing fall preventive strategies as they may influence participation and behaviors. PMID:27801936

  3. Lateglacial and holocene tephrostratigraphy in Denmark

    DEFF Research Database (Denmark)

    Larsen, Jeppe Joel

    the Eyjafjallajökull 2010 eruption. The observations of the Hässeldalen Tephra and Fosen Tephra expand the previously known depositional extent of these two tephra horizons. At Hallegård on Bornholm a distinct horizon of Laacher See-like tephra is registered c. 60 cm below the Laacher See Tephra. The tephra, here...

  4. Falls prevention for the elderly

    Directory of Open Access Journals (Sweden)

    Dagmar Lühmann

    2012-04-01

    Full Text Available Background: An ageing population, a growing prevalence of chronic diseases and limited financial resources for health care underpin the importance of prevention of disabling health disorders and care dependency in the elderly. A wide variety of measures is generally available for the prevention of falls and fall-related injuries. The spectrum ranges from diagnostic procedures for identifying individuals at risk of falling to complex interventions for the removal or reduction of identified risk factors. However, the clinical and economic effectiveness of the majority of recommended strategies for fall prevention is unclear. Against this background, the literature analyses in this HTA report aim to support decision-making for effective and efficient fall prevention.Research questions: The pivotal research question addresses the effectiveness of single interventions and complex programmes for the prevention of falls and fall-related injuries. The target population are the elderly (> 60 years, living in their own housing or in long term care facilities. Further research questions refer to the cost-effectiveness of fall prevention measures, and their ethical, social and legal implications. Methods: Systematic literature searches were performed in 31 databases covering the publication period from January 2003 to January 2010. While the effectiveness of interventions is solely assessed on the basis of randomised controlled trials (RCT, the assessment of the effectiveness of diagnostic procedures also considers prospective accuracy studies. In order to clarify social, ethical and legal aspects all studies deemed relevant with regard to content were taken into consideration, irrespective of their study design. Study selection and critical appraisal were conducted by two independent assessors. Due to clinical heterogeneity of the studies no meta-analyses were performed.Results: Out of 12,000 references retrieved by literature searches, 184 meet the

  5. Falls: Epidemiology, Pathophysiology, and Relationship to Fracture

    OpenAIRE

    Berry, Sarah D.; Miller, Ram

    2008-01-01

    Falls are common in the elderly, and frequently result in injury, disability, and institutionalization. Although the causes of falls are complex, most falls result from an interaction between individual characteristics that increase an individual's propensity to fall and acute mediating risk factors that provide the opportunity to fall. Predisposing risk factors include age-associated changes in strength and balance, age-associated comorbidities such as osteoarthritis, visual impairment and d...

  6. Development and feasibility of falls prevention advice.

    Science.gov (United States)

    van Harten-Krouwel, Diny; Schuurmans, Marieke; Emmelot-Vonk, Mariëlle; Pel-Littel, Ruth

    2011-10-01

    This study examined the feasibility of nursing falls prevention advice and factors influencing feasibility. The frequency and seriousness of falls in hospitalised patients are underestimated, and such falls should be preventable because of the presence of professionals. A best practice-based falls prevention advice was developed to decrease the incidence of secondary falls and the incidence of primary falls in the long term and to increase the knowledge of nurses about falls prevention and the seriousness of falls. A descriptive, explorative study. Feasibility of the advice for 30 patients was assessed 82 times (theoretically, three times per patient) by observation and by interviewing nurses, patients and their families. The falls prevention advice was used in 48% of the assessments. There was a difference in use between interventions. Interventions that required more knowledge, communication and extra activities were implemented the least. The absence of materials and knowledge about falls prevention were important determinants of the non-implementation of certain interventions. Before falls prevention advice is implemented, it is important to educate nurses about falls, communication skills and implementation of the advice. The falls prevention advice might help nurses to prevent falls and increase their knowledge about falls prevention. © 2011 Blackwell Publishing Ltd.

  7. Conceptual design considerations and neutronics of lithium fall laser fusion target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  8. Conceptual design considerations and neutronics of lithium fall laser target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  9. NOVA Fall 2000 Teacher's Guide.

    Science.gov (United States)

    Ransick, Kristina; Rosene, Dale; Sammons, Fran Lyons; Sammons, James

    This teacher's guide complements six programs that aired on the Public Broadcasting System (PBS) in the fall of 2000. Programs include: (1) "Lincoln's Secret Weapon"; (2) "Hitler's Lost Sub"; (3) "Runaway Universe"; (4) "Garden of Eden"; (5) "Dying to Be Thin"; and (6) "Japan's Secret…

  10. Trapping fall armyworm in Africa

    Science.gov (United States)

    Fall armyworm, Spodoptera frugiperda, is a noctuid pest of row and vegetable crops throughout the Americas. It has recently invaded Africa and has been identified from almost all sub-Saharan countries. There is a strong expectation of significant damage to African maize crop yield and a high likel...

  11. Nuclear fall-out shelter

    International Nuclear Information System (INIS)

    Lowery, R.J.

    1981-01-01

    An underground nuclear fall-out shelter has a plastics shell which, apart from service and access openings, is waterproof and provided, if desired, with a concrete roof. The shelter has an access opening, an air system, lighting, water storage, sanitation and sewage facilities. (author)

  12. Falling-sphere radioactive viscometry

    International Nuclear Information System (INIS)

    Souza, R. de.

    1987-01-01

    In this work the falling sphere viscometric method was studies experimentally using a sphere tagged with 198 Au radiosotopo, the objective being the demosntration of the advantages of this technique in relation to the traditional method. The utilisation of the falling radioactive sphere permits the point-point monitoring of sphere position as a function of count rate. The fall tube wall and end effects were determined by this technique. Tests were performed with spheres of different diameters in four tubes. The application of this technique demosntrated the wall and end effects in sphere speed. The case of sphere fall in the steady slow regime allowed the determination of the terminal velocity, showing the increase of botton end effect as the sphere approaches the tube base. In the case the transient slow regime, the sphere was initially in a state of respose near the top surface. The data obtained show the influence of the free surface and wall on the sphere acceleration. These experimental data were applied to the Basset equation on order to verify the behaviour of the terms in this equation. (author) [pt

  13. Exercises to help prevent falls

    Science.gov (United States)

    ... help prevent falls because it can: Make your muscles stronger and more flexible Improve your balance Increase how ... To make your calves and ankle muscles stronger: Hold on to a solid ... of a chair. Stand with your back straight and slightly bend ...

  14. Finding Rising and Falling Words

    NARCIS (Netherlands)

    Tjong Kim Sang, E.

    2016-01-01

    We examine two different methods for finding rising words (among which neologisms) and falling words (among which archaisms) in decades of magazine texts (millions of words) and in years of tweets (billions of words): one based on correlation coefficients of relative frequencies and time, and one

  15. AAAI 1993 Fall Symposium Reports

    OpenAIRE

    Levinson, Robert; Epstein, Susan; Terveen, Loren; Bonasso, R. Peter; Miller, David P.; Bowyer, Kevin; Hall, Lawrence

    1994-01-01

    The Association for the Advancement of Artificial Intelligence held its 1993 Fall Symposium Series on October 22-24 in Raleigh, North Carolina. This article contains summaries of the six symposia that were conducted: Automated Deduction in Nonstandard Logics; Games: Planning and Learning; Human-Computer Collaboration: Reconciling Theory, Synthesizing Practice; Instantiating Intelligent Agents; and Machine Learning and Computer Vision: What, Why, and How?

  16. Satellite-Based Thermophysical Analysis of Volcaniclastic Deposits: A Terrestrial Analog for Mantled Lava Flows on Mars

    Directory of Open Access Journals (Sweden)

    Mark A. Price

    2016-02-01

    Full Text Available Orbital thermal infrared (TIR remote sensing is an important tool for characterizing geologic surfaces on Earth and Mars. However, deposition of material from volcanic or eolian activity results in bedrock surfaces becoming significantly mantled over time, hindering the accuracy of TIR compositional analysis. Moreover, interplay between particle size, albedo, composition and surface roughness add complexity to these interpretations. Apparent Thermal Inertia (ATI is the measure of the resistance to temperature change and has been used to determine parameters such as grain/block size, density/mantling, and the presence of subsurface soil moisture/ice. Our objective is to document the quantitative relationship between ATI derived from orbital visible/near infrared (VNIR and thermal infrared (TIR data and tephra fall mantling of the Mono Craters and Domes (MCD in California, which were chosen as an analog for partially mantled flows observed at Arsia Mons volcano on Mars. The ATI data were created from two images collected ~12 h apart by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER instrument. The results were validated with a quantitative framework developed using fieldwork that was conducted at 13 pre-chosen sites. These sites ranged in grain size from ash-sized to meter-scale blocks and were all rhyolitic in composition. Block size and mantling were directly correlated with ATI. Areas with ATI under 2.3 × 10−2 were well-mantled with average grain size below 4 cm; whereas values greater than 3.0 × 10−2 corresponded to mantle-free surfaces. Correlation was less accurate where checkerboard-style mixing between mantled and non-mantled surfaces occurred below the pixel scale as well as in locations where strong shadowing occurred. However, the results validate that the approach is viable for a large majority of mantled surfaces on Earth and Mars. This is relevant for determining the volcanic history of Mars, for

  17. Person-Centered Fall Risk Awareness Perspectives: Clinical Correlates and Fall Risk.

    Science.gov (United States)

    Verghese, Joe

    2016-12-01

    To identify clinical correlates of person-centered fall risk awareness and their validity for predicting falls. Prospective cohort study. Community. Ambulatory community-dwelling older adults without dementia (N = 316; mean age 78, 55% female). Fall risk awareness was assessed using a two-item questionnaire that asked participants about overall likelihood of someone in their age group having a fall and their own personal risk of falling over the next 12 months. Incident falls were recorded over study follow-up. Fifty-three participants (16.8%) responded positively to the first fall risk awareness question about being likely to have a fall in the next 12 months, and 100 (31.6%) reported being at personal risk of falling over the next 12 months. There was only fair correlation (κ = 0.370) between responses on the two questions. Prior falls and depressive symptoms were associated with positive responses on both fall risk awareness questions. Age and other established fall risk factors were not associated with responses on either fall risk awareness question. The fall risk awareness questionnaire did not predict incident falls or injurious falls. Fall risk awareness is low in older adults. Although person-centered fall risk awareness is not predictive of falls, subjective risk perceptions should be considered when designing fall preventive strategies because they may influence participation and behaviors. © 2016, Copyright the Author Journal compilation © 2016, The American Geriatrics Society.

  18. Fixed-premium deposit insurance and international credit crunches

    OpenAIRE

    Mark M. Spiegel

    1996-01-01

    This article introduces a monopolistically competitive model of foreign lending in which both explicit and implicit fixed-premium deposit insurance increase the degree to which bank participation in relending to problem debtors falls below its globally optimal level. This provides a channel for fixed-premium deposit insurance to inhibit credit extension in bad states, resulting in an increase in the expected default percentage and an increase in the expected burden on the deposit insurance in...

  19. Intrinsic factors associated with pregnancy falls.

    Science.gov (United States)

    Wu, Xuefang; Yeoh, Han T

    2014-10-01

    Approximately 25% to 27% of women sustain a fall during pregnancy, and falls are associated with serious injuries and can affect pregnancy outcomes. The objective of the current study was to identify intrinsic factors associated with pregnancy that may contribute to women's increased risk of falls. A literature search (Medline and Pubmed) identified articles published between January 1980 and June 2013 that measured associations between pregnancy and fall risks, using an existing fall accident investigation framework. The results indicated that physiological, biomechanical, and psychological changes associated with pregnancy may influence the initiation, detection, and recovery phases of falls and increase the risk of falls in this population. Considering the logistic difficulties and ethnic concerns in recruiting pregnant women to participate in this investigation of fall risk factors, identification of these factors could establish effective fall prevention and intervention programs for pregnant women and improve birth outcomes. [Workplace Health Saf 2014;62(10):403-408.]. Copyright 2014, SLACK Incorporated.

  20. Volatile-induced magma differentiation in the plumbing system of Mt. Etna volcano (Italy): evidence from glass in tephra of the 2001 eruption

    Science.gov (United States)

    Ferlito, Carmelo; Viccaro, Marco; Cristofolini, Renato

    2008-02-01

    Mount Etna volcano was shaken during the summer 2001 by one of the most singular eruptive episodes of the last centuries. For about 3 weeks, several eruptive fractures developed, emitting lava flows and tephra that significantly modified the landscape of the southern flank of the volcano. This event stimulated the attention of the scientific community especially for the simultaneous emission of petrologically distinct magmas, recognized as coming from different segments of the plumbing system. A stratigraphically controlled sampling of tephra layers was performed at the most active vents of the eruption, in particular at the 2,100 m (CAL) and at the 2,550 m (LAG) scoria cones. Detailed scanning electron microscope and energy dispersive x-ray spectrometer (SEM-EDS) analyses performed on glasses found in tephra and comparison with lava whole rock compositions indicate an anomalous increase in Ti, Fe, P, and particularly of K and Cl in the upper layers of the LAG sequence. Mass balance and thermodynamic calculations have shown that this enrichment cannot be accounted for by “classical” differentiation processes, such as crystal fractionation and magma mixing. The analysis of petrological features of the magmas involved in the event, integrated with the volcanological evolution, has evidenced the role played by volatiles in controlling the magmatic evolution within the crustal portion of the plumbing system. Volatiles, constituted of H2O, CO2, and Cl-complexes, originated from a deeply seated magma body (DBM). Their upward migration occurred through a fracture network possibly developed by the seismic swarms during the period preceding the event. In the upper portion of the plumbing system, a shallower residing magma body (ABT) had chemical and physical conditions to receive migrating volatiles, which hence dissolved the mobilized elements producing the observed selective enrichment. This volatile-induced differentiation involved exclusively the lowest erupted

  1. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, Chile

    OpenAIRE

    Swanson,Frederick J; Jones,Julia A; Crisafulli,Charles M; Lara,Antonio

    2013-01-01

    The 2008-2009 eruption of Chaitén Volcano (Chile) involved a variety of volcanic and associated hydro-logic processes that damaged nearby forests. These processes included coarse (gravel) and fine (silt to sand) tephra fall, a laterally directed blast, fluvial deposition of remobilized tephra, a variety of low-temperature mass-movement processes, and a pyroclastic flow. Each of these geophysical processes constitutes a type of ecosystem disturbance which involves a distinctive suite of distur...

  2. Fall-related activity avoidance in relation to a history of falls or near falls, fear of falling and disease severity in people with Parkinson's disease.

    Science.gov (United States)

    Kader, Manzur; Iwarsson, Susanne; Odin, Per; Nilsson, Maria H

    2016-06-02

    There is limited knowledge concerning fall-related activity avoidance in people with Parkinson's disease (PD); such knowledge would be of importance for the development of more efficient PD-care and rehabilitation. This study aimed to examine how fall-related activity avoidance relates to a history of self-reported falls/near falls and fear of falling (FOF) as well as to disease severity in people with PD. Data were collected from 251 (61 % men) participants with PD; their median (min-max) age and PD duration were 70 (45-93) and 8 (1-43) years, respectively. A self-administered postal survey preceded a home visit which included observations, clinical tests and interview-administered questionnaires. Fall-related activity avoidance was assessed using the modified Survey of Activities and Fear of Falling in the Elderly (mSAFFE) as well as by using a dichotomous (Yes/No) question. Further dichotomous questions concerned: the presence of FOF and the history (past 6 months) of falls or near falls, followed by stating the number of incidents. Disease severity was assessed according to the Hoehn and Yahr (HY) stages. In the total sample (n = 251), 41 % of the participants reported fall-related activity avoidance; the median mSAFFE score was 22. In relation to a history of fall, the proportions of participants (p fall-related activity avoidance were: non-fallers (30 %), single fallers (50 %) and recurrent fallers, i.e. ≥ 2 falls (57 %). Among those that reported near falls (but no falls), 51 % (26 out of 51) reported fall-related activity avoidance. Of those that reported FOF, 70 % reported fall-related activity avoidance. Fall-related activity avoidance ranged from 24 % in the early PD-stage (HY I) to 74 % in the most severe stages (HY IV-V). Results indicate that fall-related activity avoidance may be related to a history of self-reported falls/near falls, FOF and disease severity in people with PD. Importantly, fall-related activity avoidance is

  3. Geological aspects of acid deposition

    International Nuclear Information System (INIS)

    Bricker, O.P.

    1984-01-01

    The general pattern of rain falling on the earth and reacting with the materials of the lithosphere (the weathering reactions so familiar to every beginning geology student) began soon after the earth was formed and has continued to the present. Anthropogenic additions to the natural acidic components of the atmosphere have increased since the time of the industrial revolution until they now rival or exceed those of the natural system. The severity of the environmental perturbations caused by these anthropogenic additions to the atmosphere has become a hotly debated topic in scientific forums and in the political arena. The six chapters in this book address various aspects of the acid deposition phenomenon from a geological perspective. It is hoped that the geological approach will be useful in bringing the problem more clearly into focus and may shed light on the geochemical processes that modify the chemical composition of acid deposition after it encounters and reacts with the materials of the lithosphere

  4. Relationship between subjective fall risk assessment and falls and fall-related fractures in frail elderly people

    OpenAIRE

    Shimada, Hiroyuki; Suzukawa, Megumi; Ishizaki, Tatsuro; Kobayashi, Kumiko; Kim, Hunkyung; Suzuki, Takao

    2011-01-01

    Abstract Background Objective measurements can be used to identify people with risks of falls, but many frail elderly adults cannot complete physical performance tests. The study examined the relationship between a subjective risk rating of specific tasks (SRRST) to screen for fall risks and falls and fall-related fractures in frail elderly people. Methods The SRRST was investigated in 5,062 individuals aged 65 years or older who were utilized day-care services. The SRRST comprised 7 dichotom...

  5. Fall Prevention in a Primary Care Setting.

    Science.gov (United States)

    Siegrist, Monika; Freiberger, Ellen; Geilhof, Barbara; Salb, Johannes; Hentschke, Christian; Landendoerfer, Peter; Linde, Klause; Halle, Martin; Blank, Wolfgang A

    2016-05-27

    Falls and fall-related injuries are common in community-dwelling elderly people. Effective multifactorial fall prevention programs in the primary care setting may be a promising approach to reduce the incidence rate of falls. In a cluster randomized trial in 33 general practices 378 people living independently and at high risk of falling (65 to 94 years old; 285 women) were allocated to either a 16 week exercise-based fall prevention program including muscle strengthening and challenging balance training exercises, combined with a 12 week home-based exercise program (222 participants), or to usual care (156 participants). The main outcome was number of falls over a period of 12 months. Secondary outcomes were the number of fall-related injuries, physical function (Timed-Up-and-Go-Test, TUG, Chair-Stand-Test, CST, modified Romberg Test), and fear of falling. In the intervention group (n=222 patients in 17 general practices) 291 falls occurred, compared to 367 falls in the usual care group (n=156 patients in 16 general practices). We observed a lower incidence rate for falls in the intervention group (incidence rate ratio/IRR: 0.54; 95% confidence interval (CI): [0.35; 0.84], p=0.007) and for fall-related injuries (IRR: 0.66; [0.42; 0.94], p=0.033). Additionally, patients in the intervention group showed significant improvements in secondary endpoints (TUG: -2.39 s, [-3.91; -0.87], p=0.014; mRomberg: 1.70 s, [0.35; 3.04], p=0.037; fear of falling: -2.28 points, [-3.87; -0.69], p=0.022) compared to usual care. A complex falls prevention program in a primary care setting was effective in reducing falls and fall-related injuries in community dwelling older adults at risk.

  6. Associated Factors for Falls, Recurrent Falls, and Injurious Falls in Aged Men Living in Taiwan Veterans Homes

    Directory of Open Access Journals (Sweden)

    Yan-Chiou Ku

    2013-06-01

    Conclusion: This study demonstrated that the advanced age, depression status, stroke, gouty arthritis, and cataract are independent variables for predicting falls; depression is the only clinical factor capable of predicting the recurrent falls. These variables were potential targets for effective prevention of falls.

  7. Relationship between subjective fall risk assessment and falls and fall-related fractures in frail elderly people

    Directory of Open Access Journals (Sweden)

    Shimada Hiroyuki

    2011-08-01

    Full Text Available Abstract Background Objective measurements can be used to identify people with risks of falls, but many frail elderly adults cannot complete physical performance tests. The study examined the relationship between a subjective risk rating of specific tasks (SRRST to screen for fall risks and falls and fall-related fractures in frail elderly people. Methods The SRRST was investigated in 5,062 individuals aged 65 years or older who were utilized day-care services. The SRRST comprised 7 dichotomous questions to screen for fall risks during movements and behaviours such as walking, transferring, and wandering. The history of falls and fall-related fractures during the previous year was reported by participants or determined from an interview with the participant's family and care staff. Results All SRRST items showed significant differences between the participants with and without falls and fall-related fractures. In multiple logistic regression analysis adjusted for age, sex, diseases, and behavioural variables, the SRRST score was independently associated with history of falls and fractures. Odds ratios for those in the high-risk SRRST group (≥ 5 points compared with the no risk SRRST group (0 point were 6.15 (p Conclusion These results suggest that subjective ratings by care staff can be utilized to determine the risks of falls and fall-related fractures in the frail elderly, however, these preliminary results require confirmation in further prospective research.

  8. A simple strategy for fall events detection

    KAUST Repository

    Harrou, Fouzi

    2017-01-20

    The paper concerns the detection of fall events based on human silhouette shape variations. The detection of fall events is addressed from the statistical point of view as an anomaly detection problem. Specifically, the paper investigates the multivariate exponentially weighted moving average (MEWMA) control chart to detect fall events. Towards this end, a set of ratios for five partial occupancy areas of the human body for each frame are collected and used as the input data to MEWMA chart. The MEWMA fall detection scheme has been successfully applied to two publicly available fall detection databases, the UR fall detection dataset (URFD) and the fall detection dataset (FDD). The monitoring strategy developed was able to provide early alert mechanisms in the event of fall situations.

  9. Infraordinary Deposits

    DEFF Research Database (Denmark)

    2016-01-01

    The exhibition Infraordinary Deposits presents three works in progress by PhD Fellow Espen Lunde Nielsen from the on-going PhD project Architectural Probes of the Infraordinary: Social Coexistence through Everyday Spaces. The infraordinary is understood as the opposite of the extraordinary...... and as that which is ‘worn half-invisible’ by use. Nevertheless, these unregarded spaces play a vital role to the social dimension of the city. The selected projects (‘urban biopsies’) on display explore how people coexist through these spaces and within the city itself, either through events in real......, daily 8.45 – 15.00 Where: Aarhus School of Architecture, The Canteen, Nørreport 18, 8000 Aarhus C...

  10. Effects of volcanic deposit disaggregation on exposed water composition

    Science.gov (United States)

    Back, W. E.; Genareau, K. D.

    2016-12-01

    Explosive volcanic eruptions produce a variety of hazards. Pyroclastic material can be introduced to water through ash fallout, pyroclastic flows entering water bodies, and/or lahars. Remobilization of tephras can occur soon after eruption or centuries later, introducing additional pyroclastic material into the environment. Introduction of pyroclastic material may alter the dissolved element concentration and pH of exposed waters, potentially impacting drinking water supplies, agriculture, and ecology. This study focuses on the long-term impacts of volcanic deposits on water composition due to the mechanical breakup of volcanic deposits over time. Preliminary work has shown that mechanical milling of volcanic deposits will cause significant increases in dissolved element concentrations, conductivity, and pH of aqueous solutions. Pyroclastic material from seven eruptions sites was collected, mechanically milled to produce grain sizes Soufriere Hills, Ruapehu), mafic (Lathrop Wells) and ultramafic (mantle xenoliths) volcanic deposits. Lathrop Wells has an average bulk concentration of 49.15 wt.% SiO2, 6.11 wt. % MgO, and 8.39 wt. % CaO and produces leachate concentrations of 85.69 mg/kg for Ca and 37.22 mg/kg for Mg. Taupo and Valles Caldera samples have a bulk concentration of 72.9 wt.% SiO2, 0.59 wt. % MgO, and 1.48 wt. % CaO, and produces leachate concentrations of 4.08 mg/kg for Ca and 1.56 mg/kg for Mg. Similar testing will be conducted on the intermediate and ultramafic samples to test the hypothesis that bulk magma composition and mineralogy will directly relate to the increased dissolved element concentration of exposed waters. The measured effects on aqueous solutions will aid in evaluation of impacts to marine and freshwater systems exposed to volcanic deposits.

  11. Relationship between subjective fall risk assessment and falls and fall-related fractures in frail elderly people.

    Science.gov (United States)

    Shimada, Hiroyuki; Suzukawa, Megumi; Ishizaki, Tatsuro; Kobayashi, Kumiko; Kim, Hunkyung; Suzuki, Takao

    2011-08-12

    Objective measurements can be used to identify people with risks of falls, but many frail elderly adults cannot complete physical performance tests. The study examined the relationship between a subjective risk rating of specific tasks (SRRST) to screen for fall risks and falls and fall-related fractures in frail elderly people. The SRRST was investigated in 5,062 individuals aged 65 years or older who were utilized day-care services. The SRRST comprised 7 dichotomous questions to screen for fall risks during movements and behaviours such as walking, transferring, and wandering. The history of falls and fall-related fractures during the previous year was reported by participants or determined from an interview with the participant's family and care staff. All SRRST items showed significant differences between the participants with and without falls and fall-related fractures. In multiple logistic regression analysis adjusted for age, sex, diseases, and behavioural variables, the SRRST score was independently associated with history of falls and fractures. Odds ratios for those in the high-risk SRRST group (≥ 5 points) compared with the no risk SRRST group (0 point) were 6.15 (p fall, 15.04 (p falls, and 5.05 (p fall-related fractures. The results remained essentially unchanged in subgroup analysis accounting for locomotion status. These results suggest that subjective ratings by care staff can be utilized to determine the risks of falls and fall-related fractures in the frail elderly, however, these preliminary results require confirmation in further prospective research.

  12. Fall prevention in central coast community pharmacies.

    Science.gov (United States)

    Stuart, Gina M; Kale, Helen L

    2018-04-19

    Fall injuries among people aged 65 years and over (older people) cause substantial health decline and cost to the health system. In 2009 in New South Wales, 25.6% of older people fell in the previous year, and 10.7% (32 000) were hospitalised. Pharmacists are trusted professionals, who interact extensively with older people and have potential to augment fall prevention in pharmacies. This brief report describes how professional development improved pharmacist's knowledge and confidence in fall prevention, encouraged implementation of fall prevention plans and facilitated the provision of brief fall prevention interventions for older clients, after identification of fall risk. In 2014, pharmacists from all Central Coast pharmacies (n = 76) were invited to free, continuing professional development (CPD) in fall prevention. It provided education and resources to identify clients' fall risk, conduct brief fall prevention interventions and implement fall prevention health promotion plans (FPHPP). Pharmacists completed written: Baseline and post-workshop questionnaires to assess changes in pharmacist's knowledge and confidence, and existing fall prevention in pharmacies. Logs of client fall risk and brief fall prevention interventions offered to clients. Four-month follow-up questionnaires to assess implementation of FPHPPs and pharmacy practice changes. Pharmacists representing 36% of pharmacies participated. At four-month follow-up, 67% had implemented FPHPPs, and 62% delivered brief interventions determined by client fall risk. Fall prevention in pharmacies can be augmented through locally provided CPD tailored for pharmacists. SO WHAT?: This model could increase fall prevention reach. It is transferable to settings where health professionals provide services to older adults and require reregistration through professional development. © 2018 Australian Health Promotion Association.

  13. Fall prevention in high-risk patients.

    Science.gov (United States)

    Shuey, Kathleen M; Balch, Christine

    2014-12-01

    In the oncology population, disease process and treatment factors place patients at risk for falls. Fall bundles provide a framework for developing comprehensive fall programs in oncology. Small sample size of interventional studies and focus on ambulatory and geriatric populations limit the applicability of results. Additional research is needed. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Risk of Falling in Older Women

    OpenAIRE

    Laura Armas; Joan Lappe; Veronica J. Slavik; Kellan Slattery; Shih-Chuan Cheng; Davender S. Malik; John N. Mordeson

    2015-01-01

    We propose a weighted average approach to measure the risk of falling in older women. We consider four causal variables of falling, namely serum 25-OHD levels, medication use, fracture, and age. We use five methods to derive linear equations with these four factors as independent variables in the linear equations with risk of falling as the dependent variable.

  15. 29 CFR 1926.760 - Fall protection.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Fall protection. 1926.760 Section 1926.760 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.760 Fall protection. (a... protection from fall hazards in accordance with paragraph (a)(1) of this section. (c) Controlled Decking Zone...

  16. 29 CFR 1917.41 - House falls.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false House falls. 1917.41 Section 1917.41 Labor Regulations...) MARINE TERMINALS Cargo Handling Gear and Equipment § 1917.41 House falls. (a) Span beams shall be secured... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels...

  17. Aerial gamma ray and magnetic survey: Minnesota Project, Thief River Falls quadrangle of Minnesota/North Dakota. Final report

    International Nuclear Information System (INIS)

    1979-11-01

    The Thief River Falls 1:250,000 scale quadrangle of Minnesota and North Dakota is almost everywhere covered with Wisconsin age glacial deposits (drift, lake sediments, etc.) of variable thickness. Where exposed, bedrock is Late Cretaceous age marine deposits. There are no uranium deposits (or occurrences) known within the quadrangle. Sixty-six groups of uranium samples were defined as anomalies and are discussed briefly. None of them are considered significant

  18. The Ottaviano eruption of Somma-Vesuvio (8000 y B.P.): a magmatic alternating fall and flow-forming eruption

    Science.gov (United States)

    Rolandi, G.; Maraffi, S.; Petrosino, P.; Lirer, L.

    1993-11-01

    The Ottaviano eruption occurred in the late neolithic (8000 y B.P.). 2.40 km 3 of phonolitic pyroclastic material (0.61 km 3 DRE) were emplaced as pyroclastic flow, surge and fall deposits. The eruption began with a fall phase, with a model column height of 14 km, producing a pumice fall deposit (LA). This phase ended with short-lived weak explosive activity, giving rise to a fine-grained deposit (L1), passing to pumice fall deposits as the result of an increasing column height and mass discharge rate. The subsequent two fall phases (producing LB and LC deposits), had model column heights of 20 and 22 km with eruption rates of 2.5 × 10 7 and 2.81 × 10 7 kg/s, respectively. These phases ended with the deposition of ash layers (L2 and L3), related to a decreasing, pulsing explosive activity. The values of dynamic parameters calculated for the eruption classify it as a sub-plinian event. Each fall phase was characterized by variations in the eruptive intensity, and several pyroclastic flows were emplaced (F1 to F3). Alternating pumice and ash fall beds record the waning of the eruption. Finally, owing to the collapse of a eruptive column of low gas content, the last pyroclastic flow (F4) was emplaced.

  19. Quantitative rock-fall hazard and risk assessment for Yosemite Valley, California

    Science.gov (United States)

    Stock, G. M.; Luco, N.; Collins, B. D.; Harp, E.; Reichenbach, P.; Frankel, K. L.

    2011-12-01

    Rock falls are a considerable hazard in Yosemite Valley, California with more than 835 rock falls and other slope movements documented since 1857. Thus, rock falls pose potentially significant risk to the nearly four million annual visitors to Yosemite National Park. Building on earlier hazard assessment work by the U.S. Geological Survey, we performed a quantitative rock-fall hazard and risk assessment for Yosemite Valley. This work was aided by several new data sets, including precise Geographic Information System (GIS) maps of rock-fall deposits, airborne and terrestrial LiDAR-based point cloud data and digital elevation models, and numerical ages of talus deposits. Using Global Position Systems (GPS), we mapped the positions of over 500 boulders on the valley floor and measured their distance relative to the mapped base of talus. Statistical analyses of these data yielded an initial hazard zone that is based on the 90th percentile distance of rock-fall boulders beyond the talus edge. This distance was subsequently scaled (either inward or outward from the 90th percentile line) based on rock-fall frequency information derived from a combination of cosmogenic beryllium-10 exposure dating of boulders beyond the edge of the talus, and computer model simulations of rock-fall runout. The scaled distances provide the basis for a new hazard zone on the floor of Yosemite Valley. Once this zone was delineated, we assembled visitor, employee, and resident use data for each structure within the hazard zone to quantitatively assess risk exposure. Our results identify areas within the new hazard zone that may warrant more detailed study, for example rock-fall susceptibility, which can be assessed through examination of high-resolution photographs, structural measurements on the cliffs, and empirical calculations derived from LiDAR point cloud data. This hazard and risk information is used to inform placement of existing and potential future infrastructure in Yosemite Valley.

  20. Falling into a black hole

    OpenAIRE

    Mathur, Samir D.

    2007-01-01

    String theory tells us that quantum gravity has a dual description as a field theory (without gravity). We use the field theory dual to ask what happens to an object as it falls into the simplest black hole: the 2-charge extremal hole. In the field theory description the wavefunction of a particle is spread over a large number of `loops', and the particle has a well-defined position in space only if it has the same `position' on each loop. For the infalling particle we find one definition of ...

  1. The variability of meteoroid falling

    Science.gov (United States)

    Velasco Herrera, V. M.; Cordero, G.

    2016-10-01

    We analysed a historical catalogue of meteoroid falling during the last 400 years. We report here for the first time the synchronization between observed meteors and solar barycentric parameters in 19.6 and 13.2 years periodicities using a new multiple cross wavelet. The group of moderated number of meteors is distributed around the positive phase of the solar barycentric periodicity of 13.2 years. While the group of severe number of meteors are distributed on the positive phase of the solar barycentric periodicity of 19.6 years. These periodicities could be associated with Jupiter periodicities. So understanding the modulation of meteoroid falling is important for determining the falling patterns of these objects and for knowing when it is more likely to expect the entry of one of these objects into the Earth's atmosphere, because bodies falling onto the Earth can cause damage from minor impacts to mass-extinctions events. One of the most extreme events was the formation of the Chicxulub impact crater 65,000,000 years ago that caused one of the five major mass extinctions in the last 500,000,000 years. During the 20th and 21st centuries, a series of events demonstrated the importance of collisions between planets and small bodies (comets and asteroids), which included our own planet. In the case of the Earth, we can cite three examples: Tunguska, Curuça and Chelyabinsk. These events invite us to think that perhaps the occurrence of this phenomenon might be more common than we realize, but the lack of communication or people in the area where they happened prevents us from having a complete record. Modern man has not witnessed the impact of large asteroids or comets on our planet, but it has been observed on other planetary bodies. The most spectacular of these events was the collision of fragments of the comet Shoemaker-Levy 9 with Jupiter in 1994. The total energy of the 21 impacts on Jupiter's atmosphere was estimated as the equivalent of tens of millions of

  2. Risk of falls after withdrawal of fall-risk-increasing drugs: a prospective cohort study

    NARCIS (Netherlands)

    van der Velde, Nathalie; Stricker, Bruno H. Ch; Pols, Huib A. P.; van der Cammen, Tischa J. M.

    2007-01-01

    AIMS: Falling in older persons is a frequent and serious clinical problem. Several drugs have been associated with increased fall risk. The objective of this study was to identify differences in the incidence of falls after withdrawal (discontinuation or dose reduction) of fall-risk-increasing drugs

  3. Increasing fall risk awareness using wearables: A fall risk awareness protocol.

    Science.gov (United States)

    Danielsen, Asbjørn; Olofsen, Hans; Bremdal, Bernt Arild

    2016-10-01

    Each year about a third of elderly aged 65 or older experience a fall. Many of these falls may have been avoided if fall risk assessment and prevention tools where available in a daily living situation. We identify what kind of information is relevant for doing fall risk assessment and prevention using wearable sensors in a daily living environment by investigating current research, distinguishing between prospective and context-aware fall risk assessment and prevention. Based on our findings, we propose a fall risk awareness protocol as a fall prevention tool integrating both wearables and ambient sensing technology into a single platform. Copyright © 2016. Published by Elsevier Inc.

  4. Fall risk factors in Parkinson's disease.

    Science.gov (United States)

    Gray, P; Hildebrand, K

    2000-08-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by tremor, rigidity, bradykinesia, gait disturbance, and postural instability. Patients with PD suffer frequent falls, yet little research has been done to identify risks specific to PD patients. The objective of this study was to identify the risk factors associated with falls for PD patients through the collection of demographic, environmental, and medical information as well as fall diaries completed during a 3-month period. Patients with a diagnosis of idiopathic PD, with and without falls, were included in the study provided they could stand and walk and had no other condition that could predispose them to falls. Of the 118 participants, 59% reported one or more falls. A total of 237 falls were reported. Duration and severity of PD symptoms, particularly freezing, involuntary movements, and walking and postural difficulties, were significantly associated with an increased risk of falls. Other factors associated with falls were postural hypotension and daily intake of alcohol. Forty percent of falls resulted in injury, but serious injury was rare. The findings have implications for reducing the risk of falls through patient education.

  5. Intrinsic Risk Factors of Falls in Elderly

    Directory of Open Access Journals (Sweden)

    Yasmin Amatullah

    2016-09-01

    Full Text Available Background: Falls are common geriatric problems. The risk factors of falls are the intrinsic and extrinsic risk factors. Studies on falls are scarcely conducted in Indonesia, especially in Bandung. Therefore, this study was conducted to identify the intrinsic risk factors of falls among elderly. Methods: A descriptive study was carried out from August to October 2013 at the Geriatric Clinic of Dr. Hasan Sadikin General Hospital Bandung. Fifty three participants were selected according to the inclusion and exclusion criteria using consecutive sampling. The determined variables in this study were classification of the risk of falls, demographic profile, history of falls, disease, and medications. After the selection, the participants were tested by Timed up-and-go test (TUGT. Moreover, an interview and analysis of medical records were carried out to discover the risk factors of falls. The collected data were analyzed and presented in the form of percentages shown in tables. Results: From 53 patients, women (35.66% were considered to have higher risk of fall than men (18.34%. The majority of patients (66% with the risk of fall were from the age group 60–74 years. The major diseases suffered by patients were hypertension, osteoarthritis and diabetes mellitus. Drugs that were widely used were antihypertensive drugs; analgesic and antipyretic drugs and antidiabetic drugs. Conclusions: There are various intrinsic risk factors of falls in elderly and each of the elderly has more than one intrinsic risk factor of falls.

  6. Nurses' Perceptions of Implementing Fall Prevention Interventions to Mitigate Patient-Specific Fall Risk Factors.

    Science.gov (United States)

    Wilson, Deleise S; Montie, Mary; Conlon, Paul; Reynolds, Margaret; Ripley, Robert; Titler, Marita G

    2016-08-01

    Evidence-based (EB) fall prevention interventions to mitigate patient-specific fall risk factors are readily available but not routinely used in practice. Few studies have examined nurses' perceptions about both the use of these EB interventions and implementation strategies designed to promote their adoption. This article reports qualitative findings of nurses' perceptions about use of EB fall prevention interventions to mitigate patient-specific fall risks, and implementation strategies to promote use of these interventions. The findings revealed five major themes: before-study fall prevention practices, use of EB fall prevention interventions tailored to patient-specific fall risk factors, beneficial implementation strategies, overall impact on approach to fall prevention, and challenges These findings are useful to guide nurses' engagement and use of EB fall prevention practices tailored to patient-specific fall risk factors. © The Author(s) 2016.

  7. Disease state fingerprint for fall risk assessment.

    Science.gov (United States)

    Similä, Heidi; Immonen, Milla

    2014-01-01

    Fall prevention is an important and complex multifactorial challenge, since one third of people over 65 years old fall at least once every year. A novel application of Disease State Fingerprint (DSF) algorithm is presented for holistic visualization of fall risk factors and identifying persons with falls history or decreased level of physical functioning based on fall risk assessment data. The algorithm is tested with data from 42 older adults, that went through a comprehensive fall risk assessment. Within the study population the Activities-specific Balance Confidence (ABC) scale score, Berg Balance Scale (BBS) score and the number of drugs in use were the three most relevant variables, that differed between the fallers and non-fallers. This study showed that the DSF visualization is beneficial in inspection of an individual's significant fall risk factors, since people have problems in different areas and one single assessment scale is not enough to expose all the people at risk.

  8. Prevalence of falls in elderly women.

    Science.gov (United States)

    Vitor, Priscila Regina Rorato; de Oliveira, Ana Carolina Kovaleski; Kohler, Renan; Winter, Gabriele Regiane; Rodacki, Cintia; Krause, Maressa Priscila

    2015-01-01

    To verify prevalence of falls and fear of falling, and to compare functional fitness among elderly women fallers and non-fallers. Seventy-eight elderly women participated in this study. Cases of falls and the fear of falling were self-reported by the elderly women, while the functional fitness was measured by a set of functional tests. Mean and standard deviation were used to describe the sample. Independent t-test was used to compare functional fitness between groups. The prevalence of falls in this sample was 32.4%. Among women fallers, 40% self-reported a high fear of falling. It is recommended that functional and resistance exercises are included in the preventive strategies for reducing risk factors for falls and its determinants in elderly women. Level of Evidence II, Prognostic-Prospective Study.

  9. The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

    Science.gov (United States)

    Van Gosen, Bradley S.; Hall, Susan M.

    2017-12-18

    This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

  10. Falls and Fear of Falling After Stroke: A Case-Control Study.

    Science.gov (United States)

    Goh, Hui-Ting; Nadarajah, Mohanasuntharaam; Hamzah, Norhamizan Binti; Varadan, Parimalaganthi; Tan, Maw Pin

    2016-12-01

    Falls are common after stroke, with potentially serious consequences. Few investigations have included age-matched control participants to directly compare fall characteristics between older adults with and without stroke. Further, fear of falling, a significant psychological consequence of falls, has only been examined to a limited degree as a risk factor for future falls in a stroke population. To compare the fall history between older adults with and without a previous stroke and to identify the determinants of falls and fear of falling in older stroke survivors. Case-control observational study. Primary teaching hospital. Seventy-five patients with stroke (mean age ± standard deviation, 66 ± 7 years) and 50 age-matched control participants with no previous stroke were tested. Fall history, fear of falling, and physical, cognitive, and psychological function were assessed. A χ 2 test was performed to compare characteristics between groups, and logistic regression was performed to determine the risk factors for falls and fear of falling. Fall events in the past 12 months, Fall Efficacy Scale-International, Berg Balance Scale, Functional Ambulation Category, Fatigue Severity Scale, Montreal Cognitive Assessment, and Patient Healthy Questionnaire-9 were measured for all participants. Fugl-Meyer Motor Assessment was used to quantify severity of stroke motor impairments. Twenty-three patients and 13 control participants reported at least one fall in the past 12 months (P = .58). Nine participants with stroke had recurrent falls (≥2 falls) compared with none of the control participants (P falling than did nonstroke control participants (P falls in the nonstroke group, whereas falls in the stroke group were not significantly associated with any measured outcomes. Fear of falling in the stroke group was associated with functional ambulation level and balance. Functional ambulation level alone explained 22% of variance in fear of falling in the stroke group

  11. Mercury Wet Scavenging and Deposition Differences by Precipitation Type.

    Science.gov (United States)

    Kaulfus, Aaron S; Nair, Udaysankar; Holmes, Christopher D; Landing, William M

    2017-03-07

    We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.

  12. Prediction of falls and/or near falls in people with mild Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Beata Lindholm

    Full Text Available To determine factors associated with future falls and/or near falls in people with mild PD.The study included 141 participants with PD. Mean (SD age and PD-duration were 68 (9.7 and 4 years (3.9, respectively. Their median (q1-q3 UPDRS III score was 13 (8-18. Those >80 years of age, requiring support in standing or unable to understand instructions were excluded. Self-administered questionnaires targeted freezing of gait, turning hesitations, walking difficulties in daily life, fatigue, fear of falling, independence in activities of daily living, dyskinesia, demographics, falls/near falls history, balance problems while dual tasking and pain. Clinical assessments addressed functional balance performance, retropulsion, comfortable gait speed, motor symptoms and cognition. All falls and near falls were subsequently registered in a diary during a six-month period. Risk factors for prospective falls and/or near falls were determined using logistic regression.Sixty-three participants (45% experienced ≥ 1 fall and/or near fall. Three factors were independent predictors of falls and/or near falls: fear of falling (OR = 1.032, p<0.001 history of near falls (OR = 3.475, p = 0.009 and retropulsion (OR = 2.813, p = 0.035. The strongest contributing factor was fear of falling, followed by a history of near falls and retropulsion.Fear of falling seems to be an important issue to address already in mild PD as well as asking about prior near falls.

  13. Near-falls in people with Parkinson's disease: Circumstances, contributing factors and association with falling.

    Science.gov (United States)

    Gazibara, Tatjana; Kisic Tepavcevic, Darija; Svetel, Marina; Tomic, Aleksandra; Stankovic, Iva; Kostic, Vladimir S; Pekmezovic, Tatjana

    2017-10-01

    To describe circumstances of near-falls among persons with Parkinson's disease (PD), assess factors associated with near-falling and assess whether near-falls in the first 6 months are associated with falling in the latter 6 months over one year of follow-up. In the period August 2011-December 2012, 120 consecutive persons with PD, who denied having fallen in the past 6 months, were recruited at Clinical center of Serbia in Belgrade. Occurrence of falling and near-falls was followed for one year. A total of 31 persons with PD (25.8%) experienced near-falls, but did not fall. Of 42 fallers, 32 (76.2%) experienced near-falls. Tripping was the most common cause of near-falls among fallers, whereas postural instability was the most common in non-fallers. Regardless of falling experience, the most common manner to avoid fall was holding onto furniture or wall. After adjustment for multiple motor and non-motor PD features, more severe freezing of gait was associated with occurrence of near-falls over one year of follow-up (odds ratio [OR]=1.08, 95% confidence interval [CI] 1.01-1.16; p=0.043). Adjusted regression analysis did not show associations between near-falling in the first 6 months and falling in the latter 6 months of follow-up. Near-falls commonly occur in persons with PD. More severe freezing of gait appears to predispose near-falling. Fall prevention programs focusing on balance maintenance when experiencing freezing of gait could potentially be useful in reduction of near-falls. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. New methods for fall risk prediction.

    Science.gov (United States)

    Ejupi, Andreas; Lord, Stephen R; Delbaere, Kim

    2014-09-01

    Accidental falls are the leading cause of injury-related death and hospitalization in old age, with over one-third of the older adults experiencing at least one fall or more each year. Because of limited healthcare resources, regular objective fall risk assessments are not possible in the community on a large scale. New methods for fall prediction are necessary to identify and monitor those older people at high risk of falling who would benefit from participating in falls prevention programmes. Technological advances have enabled less expensive ways to quantify physical fall risk in clinical practice and in the homes of older people. Recently, several studies have demonstrated that sensor-based fall risk assessments of postural sway, functional mobility, stepping and walking can discriminate between fallers and nonfallers. Recent research has used low-cost, portable and objective measuring instruments to assess fall risk in older people. Future use of these technologies holds promise for assessing fall risk accurately in an unobtrusive manner in clinical and daily life settings.

  15. [Falls of older individuals: medical assessment].

    Science.gov (United States)

    De Breucker, S; Nkodo Mekongo, Y P; Ibebeke, B; Pepersack, T

    2007-01-01

    Falls are one of the most common problems that threaten the independence of older individuals. They usually occur when impairments in multiple domains compromise the compensatory ability of the individual, as is the case for many geriatric syndromes. A number of the physical conditions and environmental situations predispose to falls. The medical risk factors of falls are reviewed. Falls in older individuals are rarely due to a single cause. Mechanisms that maintain postural stability are altered with aging (balance, gait speed, cardiovascular function). Female gender, past history of a fall, cognitive impairment, lower extremity weakness, balance problems, psychotropic drug use, arthritis, history of stroke, orthostatic hypotension, dizziness, and anemia represent the most frequent causes of risk of falls. Physical examination should focus upon the above mentioned risk factors and also on the presence of orthostatic hypotension, visual acuity, hearing assessment, examination of the extremities for deformities or neuropathies, and carotid sinus hypersensitivity which contributes to falls in people with unexplained falls. In conclusion, assessment of older individual at risk of falls or who fall present medical specificities. However, these latter specificities should be included in a comprehensive assessment which focus on intrinsic and extrinsic factors. Interventional strategies including comprehensive and interdisciplinary assessment lead to effective prevention.

  16. Internship Progress Summary: Fall 2016

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ralph S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Valencia, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-13

    This fall I had the opportunity to work at Los Alamos National Laboratory for the Technology Applications engineering group. I assisted two main projects during my appointment, both related to the Lab’s mission statement: “To solve national security challenges through scientific excellence.” My first project, a thermal source transfer unit, involved skills such as mechanical design, heat transfer simulation, and design analysis. The goal was to create a container that could protect a heat source and regulate its temperature during transit. I generated several designs, performed heat transfer simulations, and chose a design for prototyping. The second project was a soil drying unit for use in post blast sample analysis. To ensure fast and accurate sample processing, agents in the field wanted a system that could process wet dirt and turn it into dry powder. We designed a system of commercially available parts, and we tested the systems to determine the best methods and processes.

  17. Voices Falling Through the Air

    Directory of Open Access Journals (Sweden)

    Paul Elliman

    2012-11-01

    Full Text Available Where am I? Or as the young boy in Jules Verne’s Journey to the Centre of the Earth calls back to his distant-voiced companions: ‘Lost… in the most intense darkness.’ ‘Then I understood it,’ says the boy, Axel, ‘To make them hear me, all I had to do was to speak with my mouth close to the wall, which would serve to conduct my voice, as the wire conducts the electric fluid’ (Verne 1864. By timing their calls, the group of explorers work out that Axel is separated from them by a distance of four miles, held in a cavernous vertical gallery of smooth rock. Feeling his way down towards the others, the boy ends up falling, along with his voice, through the space. Losing consciousness he seems to give himself up to the space...

  18. Falls and Fall Prevention in Older Adults With Early-Stage Dementia: An Integrative Review.

    Science.gov (United States)

    Lach, Helen W; Harrison, Barbara E; Phongphanngam, Sutthida

    2017-05-01

    Older adults with mild cognitive impairment (MCI) and early-stage dementia have an increased risk of falling, with risks to their health and quality of life. The purpose of the current integrative review was to evaluate evidence on fall risk and fall prevention in this population. Studies were included if they examined falls or fall risk factors in older adults with MCI or early-stage dementia, or reported interventions in this population; 40 studies met criteria. Evidence supports the increased risk of falls in individuals even in the early stages of dementia or MCI, and changes in gait, balance, and fear of falling that may be related to this increased fall risk. Interventions included exercise and multifactorial interventions that demonstrated some potential to reduce falls in this population. Few studies had strong designs to provide evidence for recommendations. Further study in this area is warranted. [Res Gerontol Nurs. 2017; 10(03):139-148.]. Copyright 2016, SLACK Incorporated.

  19. Meanings of Falls and Prevention of Falls According to Rehabilitation Nurses: A Qualitative Descriptive Study.

    Science.gov (United States)

    Bok, Amy; Pierce, Linda L; Gies, Cheryl; Steiner, Victoria

    2016-01-01

    Guided by Friedemann's theoretical framework, this survey explored the meaning of a fall of an institutionalized older adult or fall prevention to rehabilitation registered nurses and whether the experience changed the nurse's practice. Qualitative, descriptive survey. A convenience sample of 742 rehabilitation nurses was asked to describe these experiences and the impact on their practice. Themes discovered related to the meaning of a fall include negative feelings (incongruence) and positive feelings (congruence). Themes related to the meaning of preventing a fall include positive feelings (congruence). Practice change themes emerged from both the experience of a fall and fall prevention. Practice change themes were drawn to Friedemann's (1995) process dimensions. Nurses' experiences and meanings of falls uncovered negative and positive feelings about these falls. New findings of this study were the positive feelings expressed by nurses, when there was no injury or when a fall was prevented. © 2015 Association of Rehabilitation Nurses.

  20. Characteristics and fall experiences of older adults with and without fear of falling outdoors.

    Science.gov (United States)

    Chippendale, Tracy; Lee, Chang Dae

    2018-06-01

    Using a theoretical model that combines an ecological perspective and Bandura's theory of self-efficacy as a guide, we sought to compare experiences and characteristics of community dwelling older adults with and without concern about falling outdoors. A survey of randomly selected community dwelling older adults across NYC (N = 120) was conducted using the outdoor falls questionnaire. Descriptive quantitative analyses of participant characteristics were conducted for all participants and for those with and without concern about falling outside. Conventional content analysis using two coders was employed to examine outdoor fall experiences for each group. A mixed methods matrix was used to integrate qualitative and quantitative findings. Some participant characteristics were more common among those with a concern about falling outside such as decreased functional status, female gender, and number of prior outdoor falls. As per descriptions of outdoor fall experiences, participants with concern were more likely to report a fall while climbing stairs or stepping up a curb, describe an intrinsic factor as a cause of their fall, use an injury prevention strategy during the fall, sustain a moderate to severe injury, seek medical attention, have had an ambulance called, require help to get up, and describe implementation of a behavioral change after the fall. Differences exist in participant characteristics and outdoor fall experiences of those with and without concern about falling outside. The proposed model can be used to understand fear of falling outdoors and can help to inform the target population and content of intervention programs.

  1. Predicting Falls in People with Multiple Sclerosis: Fall History Is as Accurate as More Complex Measures

    Directory of Open Access Journals (Sweden)

    Michelle H. Cameron

    2013-01-01

    Full Text Available Background. Many people with MS fall, but the best method for identifying those at increased fall risk is not known. Objective. To compare how accurately fall history, questionnaires, and physical tests predict future falls and injurious falls in people with MS. Methods. 52 people with MS were asked if they had fallen in the past 2 months and the past year. Subjects were also assessed with the Activities-specific Balance Confidence, Falls Efficacy Scale-International, and Multiple Sclerosis Walking Scale-12 questionnaires, the Expanded Disability Status Scale, Timed 25-Foot Walk, and computerized dynamic posturography and recorded their falls daily for the following 6 months with calendars. The ability of baseline assessments to predict future falls was compared using receiver operator curves and logistic regression. Results. All tests individually provided similar fall prediction (area under the curve (AUC 0.60–0.75. A fall in the past year was the best predictor of falls (AUC 0.75, sensitivity 0.89, specificity 0.56 or injurious falls (AUC 0.69, sensitivity 0.96, specificity 0.41 in the following 6 months. Conclusion. Simply asking people with MS if they have fallen in the past year predicts future falls and injurious falls as well as more complex, expensive, or time-consuming approaches.

  2. Medication use and fall-risk assessment for falls in an acute care hospital.

    Science.gov (United States)

    Chiu, Ming-Huang; Lee, Hsin-Dai; Hwang, Hei-Fen; Wang, Shih-Chieh; Lin, Mau-Roung

    2015-07-01

    A nested case-control study was carried out to examine relationships of a fall-risk score and the use of single medications and polypharmacy with falls among hospitalized patients aged 50 years and older in Taiwan. There were 83 patients who experienced a fall during hospitalization in an acute-care hospital. Matched by age and sex, five control patients for each case were randomly selected from all other inpatients who had not experienced any fall at the time of the index fall. Patients who took tricyclic antidepressants, diuretics, and narcotics were 3.36-, 1.83- and 2.09-fold, respectively, more likely to experience a fall than their counterparts. Conversely, patients who took beta-blockers were 0.34-fold more likely than those who did not take them to experience a fall. Patients taking ≥6 medications were 3.08-fold more likely than those taking fewer medications to experience a fall, whereas those with anxiety were 4.72-fold more likely to experience a fall than those without. A high fall-risk score was not significantly associated with the occurrence of falls. Among older hospitalized patients, tricyclic antidepressants, diuretics, narcotics, and polypharmacy should be mindfully prescribed and reviewed on a regular basis. A fall-risk scale developed from community-dwelling older people might not accurately predict falls in hospitalized patients. Further research to validate the negative effect of beta-blocker use on falls is required. © 2014 Japan Geriatrics Society.

  3. A new ELSA time series of tephra layers and paleobotanical evidence from laminated Eifel maar sediments covering the entire last 120,000 years

    Science.gov (United States)

    Sirocko, Frank; Knapp, Hannes; Klee, Marlies; Rothacker, Leo; Kromer, Bernd

    2014-05-01

    The ELSA Project has drilled a total of 50 sediment cores (2000 m of laminated lake sediment) from Eifel maar lakes and dry maar structures during the last 15 years. These records have been dated using 7 different methods, including 370 14C dates. Ten records reveal the established palynological succession of trees during the Holocene down to the Laacher See Tephra, which is used for synchronization with seven more recently drilled laminated sediment cores, which all are 14C-dated too and analyzed for tephra, pollen and paleobotanical macroremains. The seven newly established records reveal a continuous MIS2 section with mosses, ostracods and characea oogonia. They show that the 28.000 - 40.000 BP has witnessed an open landscape dominated by grass, but with rhythmic spread of conifer trees following the Greenland interstadial/succession. Seeds of Ranunculae provide excellent material for 14C dating. Even deciduous trees are present in small amounts until 28.000 BP. The time from 48.000 to 40.000 BP is characterized by a pronounced transition from the open landscape to an early MIS3 spruce (Picea) dominated forest during Greenland Interstadial GI17-14. Modern man apparently arrived at the end of this principal vegetation change near 40,000 BP. Volcanic activity in the Eifel had a stable and pronounced recurrence from 55,000 - 30,000 BP every 4000 years, but commenced with the beginning of MIS2. This landscape evolution with a forested early MIS3 is quite different to peat and sediment records from Netherlands/ Northern Germany/Scandinavia/ Poland, but is similar to conditions in parts of Switzerland. We address the early MIS3 forest to the nearby continuously moist soils and warm conditions in the nearby Mosel valley, i.e. on those stands where wine is growing today, and which most likely had served as a local refugia even for deciduous trees during MIS4 and MIS3. The MIS5 sections of the presented ELSA records reach down at least to the beginning of MIS5d near 118

  4. Geochemical signatures of tephras from Quaternary Antarctic Peninsula volcanoes Geoquímica de tefras de volcanes Cuaternarios de la Península Antártica

    Directory of Open Access Journals (Sweden)

    Stefan Kraus

    2013-01-01

    Full Text Available In the northern Antarctic Peninsula area, at least 12 Late Plelstocene-Holocene volcanic centers could be potential sources of tephra layers in the region. We present unique geochemical fingerprints for ten of these volcanoes using major, trace, rare earth element, and isotope data from 95 samples of tephra and other eruption products. The volcanoes have predominantly basaltic and basaltic andesitic compositions. The Nb/Y ratio proves useful to distinguish between volcanic centers located on the eastern (Larsen Rift and those situated on the western side (Bransfield Rift of the Antarctic Peninsula. In addition, the Sr/Nb ratio (for samples with SiO2 En la parte norte de la Península Antártica existen, por lo menos, 12 centros volcánicos del Pleistoceno Tardío-Holoceno que podrían representar las fuentes de horizontes de tefra reconocidos en la región. Se reportan aquí análisis químicos de 10 de estos volcanes, que incluyen análisis de elementos mayores, trazas, tierras raras y composición isotópica de 95 muestras de tefra u otros productos eruptivos. Los volcanes tienen, en su mayoría, composición basáltica a basáltico-andesítica. Las razones Nb/Y resultan útiles para distinguir entre centros volcánicos ubicados al lado oriental (Larsen Rift de aquellos ubicados al lado occidental (Bransfield Rift de la Península Antártica. Adicionalmente, las razones Sr/Nb (para muestras con SiO2 <63 wt%, Sr/Y, Ba/La, Zr/Hf y Th/Nb sirven para caracterizar los productos generados por cada centro volcánico. Análisis de microsonda en vidrio muestran que las rocas estudiadas tienen bajos contenidos de K2O, y que vidrios de rocas provenientes de volcanes ubicados en el rift de Bransfield son ricos en SiO2, mientras que las de volcanes del rift de Larsen tienden hacía contenidos elevados de álcalis. Se propone un algoritmo para la identificación del volcán de origen de un horizonte de tefra cualquiera, basado en las distintivas

  5. Masculinity and preventing falls: insights from the fall experiences of men aged 70 years and over.

    Science.gov (United States)

    Liddle, J L M; Lovarini, Meryl; Clemson, Lindy M; Jang, Haeyoung; Lord, Stephen R; Sherrington, Catherine; Willis, Karen

    2018-01-11

    To explore men's fall experiences through the lens of masculine identities so as to assist health professionals better engage men in fall prevention programs. Twenty-five men, aged 70-93 years who had experienced a recent fall, participated in a qualitative semi-structured interview. Men's willingness to engage in fall prevention programs taking account of individual contexts and expressions of masculinity, were conceptualised using constant comparative methods. Men's willingness to engage in fall prevention programs was related to their perceptions of the preventability of falls; personal relevance of falls; and age, health, and capability as well as problem-solving styles to prevent falls. Fall prevention advice was rarely given when men accessed the health system at the time of a fall. Contrary to dominant expectations about masculine identity, many men acknowledged fall vulnerability indicating they would attend or consider attending, a fall prevention program. Health professionals can better engage men by providing consistent messages that falls can be prevented; tailoring advice, understanding men are at different stages in their awareness of fall risk and preferences for action; and by being aware of their own assumptions that can act as barriers to speaking with men about fall prevention. Implications for rehabilitation Men accessing the health system at the time of the fall, and during rehabilitation following a fall represent prime opportunities for health professionals to speak with men about preventing falls and make appropriate referrals to community programs. Tailored advice will take account of individual men's perceptions of preventability; personal relevance; perceptions of age, health and capability; and problem-solving styles.

  6. Geriatric falls: prevention strategies for the staff.

    Science.gov (United States)

    Brady, R; Chester, F R; Pierce, L L; Salter, J P; Schreck, S; Radziewicz, R

    1993-09-01

    1. Multiple falls and injuries are more prevalent among elderly over the age of 75 and are the second leading cause of accidental death in the elderly. The risk for falling is noted to be significantly greater in the hospitalized elderly. 2. Review of retrospective quality improvement chart audits revealed that peak fall times were associated with the patient's need for toileting, rest, and obtaining nutrition and hydration. 3. The MetroHealth Falls Prevention Program is based on simple proactive measures to prevent falls in the elderly. 4. An effective falls prevention program has several implications for gerontological nursing practice, including less restraint use, increased patient autonomy, and decreased loss of self-esteem. There is also a sense of increased nursing control over patient safety and time management, as well as implications for further nursing research.

  7. IDENTIFYING ROOF FALL PREDICTORS USING FUZZY CLASSIFICATION

    International Nuclear Information System (INIS)

    Bertoncini, C. A.; Hinders, M. K.

    2010-01-01

    Microseismic monitoring involves placing geophones on the rock surfaces of a mine to record seismic activity. Classification of microseismic mine data can be used to predict seismic events in a mine to mitigate mining hazards, such as roof falls, where properly bolting and bracing the roof is often an insufficient method of preventing weak roofs from destabilizing. In this study, six months of recorded acoustic waveforms from microseismic monitoring in a Pennsylvania limestone mine were analyzed using classification techniques to predict roof falls. Fuzzy classification using features selected for computational ease was applied on the mine data. Both large roof fall events could be predicted using a Roof Fall Index (RFI) metric calculated from the results of the fuzzy classification. RFI was successfully used to resolve the two significant roof fall events and predicted both events by at least 15 hours before visual signs of the roof falls were evident.

  8. Reply to Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on the 0.1 Ma Toya Tephra, Japan"

    Science.gov (United States)

    Ito, Hisatoshi

    2015-04-01

    Guillong et al. (2015) mentioned that corrections for abundance sensitivity for 232Th and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon for LA-ICP-MS analyses. There is no denying that more rigorous treatments are necessary to obtain more reliable ages than those in Ito (2014). However, as shown in Fig. 2 in Guillong et al. (2015), the uncorrected (230Th)/(238U) for reference zircons except for Mud Tank are only 5-20% higher than unity. Since U abundance of Toya Tephra zircons that have U-Pb ages Ito (2014) obtained U-Th ages of the Toya Tephra by comparison with Fish Canyon Tuff (FCT) data. Because both the FCT and the Toya Tephra have similar trends of overestimation of 230Th, the effect of overestimation of 230Th to cause overestimation of U-Th age should be cancelled out or negligible. Therefore the pivotal conclusion in Ito (2014) that simultaneous U-Pb and U-Th dating using LA-ICP-MS is possible and useful for Quaternary zircons holds true.

  9. Gait, mobility, and falls in older people

    OpenAIRE

    Gschwind, Yves Josef

    2012-01-01

    My doctoral thesis contributes to the understanding of gait, mobility, and falls in older people. All presented projects investigated the most prominent and sensitive markers for fall-related gait changes, that is gait velocity and gait variability. Based on the measurement of these spatio-temporal gait parameters, particularly when using a change-sensitive dual task paradigm, it is possible to make conclusions regarding walking, balance, activities of daily living, and falls in o...

  10. Falls and fear of falling predict future falls and related injuries in ambulatory individuals with spinal cord injury: a longitudinal observational study

    Directory of Open Access Journals (Sweden)

    Vivien Jørgensen

    2017-04-01

    Conclusion: Ambulatory individuals have a high risk of falling and of fall-related injuries. Fall history, fear of falling and walking speed could predict recurrent falls and injurious falls. Further studies with larger samples are needed to validate these findings. [Jørgensen V, Butler Forslund E, Opheim A, Franzén E, Wahman K, Hultling C, Seiger Å, Ståhle A, Stanghelle JK, Roaldsen KS (2017 Falls and fear of falling predict future falls and related injuries in ambulatory individuals with spinal cord injury: a longitudinal observational study. Journal of Physiotherapy 63: 108–113

  11. Prevalence of falls in elderly women

    OpenAIRE

    Vitor,Priscila Regina Rorato; Oliveira,Ana Carolina Kovaleski de; Kohler,Renan; Winter,Gabriele Regiane; Rodacki,Cintia; Krause,Maressa Priscila

    2015-01-01

    OBJECTIVE: To verify prevalence of falls and fear of falling, and to compare functional fitness among elderly women fallers and non-fallers. METHODS: Seventy-eight elderly women participated in this study. Cases of falls and the fear of falling were self-reported by the elderly women, while the functional fitness was measured by a set of functional tests. Mean and standard deviation were used to describe the sample. Independent t-test was used to compare functional fitness between groups. RES...

  12. Radar fall detection using principal component analysis

    Science.gov (United States)

    Jokanovic, Branka; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem

    2016-05-01

    Falls are a major cause of fatal and nonfatal injuries in people aged 65 years and older. Radar has the potential to become one of the leading technologies for fall detection, thereby enabling the elderly to live independently. Existing techniques for fall detection using radar are based on manual feature extraction and require significant parameter tuning in order to provide successful detections. In this paper, we employ principal component analysis for fall detection, wherein eigen images of observed motions are employed for classification. Using real data, we demonstrate that the PCA based technique provides performance improvement over the conventional feature extraction methods.

  13. Ageing vision and falls: a review.

    Science.gov (United States)

    Saftari, Liana Nafisa; Kwon, Oh-Sang

    2018-04-23

    Falls are the leading cause of accidental injury and death among older adults. One of three adults over the age of 65 years falls annually. As the size of elderly population increases, falls become a major concern for public health and there is a pressing need to understand the causes of falls thoroughly. While it is well documented that visual functions such as visual acuity, contrast sensitivity, and stereo acuity are correlated with fall risks, little attention has been paid to the relationship between falls and the ability of the visual system to perceive motion in the environment. The omission of visual motion perception in the literature is a critical gap because it is an essential function in maintaining balance. In the present article, we first review existing studies regarding visual risk factors for falls and the effect of ageing vision on falls. We then present a group of phenomena such as vection and sensory reweighting that provide information on how visual motion signals are used to maintain balance. We suggest that the current list of visual risk factors for falls should be elaborated by taking into account the relationship between visual motion perception and balance control.

  14. The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures

    Science.gov (United States)

    Suess, S. T.; Poletto, G.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    SOHO-Ulysses quadrature occurs when the SOHO-Sun-Ulysses included angle is 90 degrees. It is only at such times that the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO instruments and then later be sampled in situ by Ulysses instruments. The quadratures in December 2000 and 2001 are of special significance because Ulysses will be near the south and north heliographic poles, respectively, and the solar cycle will be near sunspot maximum. Quadrature geometry is sometimes confusing and observations are influenced by solar rotation. The Fall 2000 and 2001 quadratures are more complex than usual because Ulysses is not in a true polar orbit and the orbital speed of Ulysses about the Sun is becoming comparable to the speed of SOHO about the Sun. In 2000 Ulysses will always be slightly behind the pole but will appear to hang over the pole for over two months because it is moving around the Sun in the same direction as SOHO. In 2001 Ulysses will be slightly in front of the pole so that its footpoint will be directly observable. Detailed plots will be shown of the relative positions of SOHO and Ulysses will their relative positions. In neither case is true quadrature actually achieved, but this works to the observers advantage in 2001.

  15. Falls, a fear of falling and related factors in older adults with complex chronic disease.

    Science.gov (United States)

    Lee, JuHee; Choi, MoonKi; Kim, Chang Oh

    2017-12-01

    To identify factors influencing falls and the fear of falling among older adults with chronic diseases in Korea. The fear of falling and falls in older adults are significant health problems towards which healthcare providers should direct their attention. Further investigation is needed to improve nursing practice specifically decreasing risk of falls and the fear of falling in Korea. Descriptive, cross-sectional survey. A convenience sample of 108 patients was recruited at the geriatric outpatient department of a tertiary hospital in Seoul, Korea. Demographic characteristics, comorbidities, medication use, fall history, level of physical activity, activities of daily living, mobility, muscle strength, and a fear of falling were investigated. Student's t tests, chi-square tests and multiple linear regressions were used in statistical analysis. Thirty-six participants (33.3%) among 108 subjects reported experiencing ≥1 falls in the past year. Marital status and the use of antipsychotics were associated with falls, while other factors were not significantly related to falls. Only benign prostatic hypertrophy and polypharmacy were significantly related to the fear of falling in the analysis of the relationships between chronic disease, medication use and fear of falling. In the regression model, the number of comorbidities, level of physical activity, activities of daily living and mobility were predictors of a fear of falling. Medication use was marginally significant, in the model. Increasing physical activity, functional fitness and physical independence is important to decrease the fear of falling, and to encourage active and healthy lives in older adults. The findings from this study provide evidence for the development of nursing interventions for older adults. We recommend early screening for a fear of falling and nursing interventions to decrease the fear of falling through enhancing physical activity level and function. © 2017 John Wiley & Sons Ltd.

  16. Which Fall Ascertainment Method Captures Most Falls in Pre-Frail and Frail Seniors?

    Science.gov (United States)

    Teister, Corina J; Chocano-Bedoya, Patricia O; Orav, Endel J; Dawson-Hughes, Bess; Meyer, Ursina; Meyer, Otto W; Freystaetter, Gregor; Gagesch, Michael; Rizzoli, Rene; Egli, Andreas; Theiler, Robert; Kanis, John A; Bischoff-Ferrari, Heike A

    2018-06-15

    There is no consensus on most reliable falls ascertainment method. Therefore, we investigated which method captures most falls among pre-frail and frail seniors from two randomized controlled trials conducted in Zurich, Switzerland, a 18-month trial (2009-2010) including 200 community-dwelling pre-frail seniors with a prior fall and a 12-month trial (2005-2008) including 173 frail seniors with acute hip fracture. Both included the same fall ascertainment methods: monthly active-asking, daily self-report diary, and a call-in hotline. We compared number of falls reported and estimated overall and positive percent agreement between methods. Pre-frail seniors reported 499 falls (rate = 2.5/year) and frail seniors reported 205 falls (rate = 1.4/year). Most falls were reported by active-asking: 81% of falls in pre-frail, and 78% in frail seniors. Among pre-frail seniors, diaries captured additional 19% falls, while hotline added none. Among frail seniors, hotline added 16% falls, while diaries added 6%. The positive percent agreement between active-asking and diary was 100% among pre-frail and 88% among frail seniors. While monthly active-asking captures most falls in both groups, this method alone missed 19% of falls in pre-frail and 22% in frail seniors. Thus, a combination of active-asking and diaries for pre-frail, and active-asking and the hotline for frail seniors is warranted.

  17. Impact of Fall Prevention on Nurses and Care of Fall Risk Patients.

    Science.gov (United States)

    King, Barbara; Pecanac, Kristen; Krupp, Anna; Liebzeit, Daniel; Mahoney, Jane

    2018-03-19

    Falls are common events for hospitalized older adults, resulting in negative outcomes both for patients and hospitals. The Center for Medicare and Medicaid (CMS) has placed pressure on hospital administrators by identifying falls as a "never event", resulting in a zero falls goal for many hospitals. Staff nurses are responsible for providing direct care to patients and for meeting the hospital no falls goal. Little is known about the impact of "zero falls" on nurses, patients and the organization. A qualitative study, using Grounded Dimensional Analysis (GDA) was conducted to explore nurses' experiences with fall prevention in hospital settings and the impact of those experiences on how nurses provide care to fall risk patients. Twenty-seven registered nurses and certified nursing assistants participated in in-depth interviews. Open, axial and selective coding was used to analyze data. A conceptual model which illustrates the impact of intense messaging from nursing administration to prevent patient falls on nurses, actions nurses take to address the message and the consequences to nurses, older adult patients and to the organization was developed. Intense messaging from hospital administration to achieve zero falls resulted in nurses developing a fear of falls, protecting self and unit, and restricting fall risk patients as a way to stop messages and meet the hospital goal. Results of this study identify unintended consequences of fall prevention message on nurses and older adult patients. Further research is needed understand how nurse care for fall risk patients.

  18. How Do Community-Dwelling Persons with Alzheimer Disease Fall Falls in the FINALEX Study

    Directory of Open Access Journals (Sweden)

    Niko M. Perttila

    2017-06-01

    Full Text Available Background: People with dementia are at high risk for falls. However, little is known of the features causing falls in Alzheimer disease (AD. Our aim was to investigate how participants with AD fall. Methods: In the FINALEX (Finnish Alzheimer Disease Exercise Trial study, participants’ (n = 194 falls were followed up for 1 year by diaries kept by their spouses. Results: The most common reason for falls (n = 355 was stumbling (n = 61. Of the falls, 123 led to injuries, 50 to emergency department visits, and 13 to fractures. The participants without falls (n = 103 were younger and had milder dementia than those with 1 (n = 34 or ≥2 falls (n = 57. Participants with a Mini Mental State Examination score of around 10 points were most prone to fall. In adjusted regression models, good nutritional status, good physical functioning, and use of antihypertensive medication (incident rate ratio [IRR] 0.68, 95% confidence interval [CI] 0.54–0.85 protected against falls, whereas fall history (IRR 2.71, 95% CI 2.13–3.44, osteoarthritis, diabetes mellitus, chronic obstructive pulmonary disease, higher number of drugs, drugs with anticholinergic properties, psychotropics, and opioids (IRR 4.27, 95% CI 2.92–6.24 were risk factors for falls. Conclusions: Our study provides a detailed account on how and why people with AD fall, suggesting several risk and protective factors.

  19. Is a fall just a fall : correlates of falling in healthy older persons. The Health, Aging and Body Composition Study

    NARCIS (Netherlands)

    de Rekeneire, Nathalie; Visser, Marjolein; Peila, Rita; Nevitt, Michael C; Cauley, Jane A; Tylavsky, Frances A; Simonsick, Eleanor M; Harris, Tamara B

    OBJECTIVES: To identify factors associated with falling in well-functioning older people. DESIGN: Cross-sectional analyses of report of falls over the past 12 months using baseline data from the Health, Aging and Body Composition Study. SETTING: Clinic examinations in Pittsburgh, Pennsylvania, or

  20. Self-reported preclinical mobility limitation and fall history as predictors of future falls in older women: prospective cohort study

    DEFF Research Database (Denmark)

    Mänty, Minna Regina; Heinonen, A; Viljanen, A

    2010-01-01

    mobility limitation. Fall history was recalled for previous 12 months and dichotomized. The incidence of future falls over 12 months was followed up with fall calendars. RESULTS: During the fall follow-up, a total of 440 falls were reported by 201 participants. Among those with fall history, women...

  1. Inferring the effects of compositional boundary layers on crystal nucleation, growth textures, and mineral chemistry in natural volcanic tephras through submicron-resolution imaging

    Directory of Open Access Journals (Sweden)

    Georg F. Zellmer

    2016-09-01

    Full Text Available Crystal nucleation and growth are first order processes captured in volcanic rocks and record important information about the rates of magmatic processes and chemical evolution of magmas during their ascent and eruption. We have studied glass-rich andesitic tephras from the Central Plateau of the Southern Taupo Volcanic Zone by electron- and ion-microbeam imaging techniques to investigate down to sub-micrometre scale the potential effects of compositional boundary layers (CBLs of melt around crystals on the nucleation and growth of mineral phases and the chemistry of crystal growth zones. We find that CBLs may influence the types of mineral phases nucleating and growing, and growth textures such as the development of swallowtails. The chemistry of the CBLs also has the capacity to trigger intermittent overgrowths of nanometre-scale bands of different phases in rapidly growing crystals, resulting in what we refer to as cryptic phase zoning. The existence of cryptic phase zoning has implications for the interpretation of microprobe compositional data, and the resulting inferences made on the conditions of magmatic evolution. Identification of cryptic phase zoning may in future lead to more accurate thermobarometric estimates and thus geospeedometric constraints. In future, a more quantitative characterization of CBL formation and its effects on crystal nucleation and growth may contribute to a better understanding of melt rheology and magma ascent processes at the onset of explosive volcanic eruptions, and will likely be of benefit to hazard mitigation efforts.

  2. Approach to Fall in Elderly Population

    Directory of Open Access Journals (Sweden)

    Mehmet Ilkin Naharci

    2009-10-01

    Full Text Available Falls are one of the geriatric syndromes which occur commonly and significantly increase morbidity and mortality rates in elderly. The incidence of falls increases with age. Falls usually occur when impairments in cognitive, behavioral, and executive function begin. The incidence of fall is between 30 and 40 percent of community-dwelling people and approximately 50 percent of individuals in the long-term care setting over the age of 65 years. Fracture (hip, arm, wrist, pelvis, head trauma or major lacerations, as defined serious wounding, occur 10-25% of elderly cases. Fall is overlooked in clinical examination due to various reasons; the patient never mentions the event to a doctor; there is no injury at the time of the fall; the doctor fails to ask the patient about a history of falls; or either doctor or patient erroneously believes that falls are an inevitable part of the aging process. Elderly give not usually any self-information about fall, for this reason, all older patients should be asked at least once per year about falls and should be assessed in terms of balance and gait disorders. There are many distinct causes for falls in old people. Falls in older individuals occur when a threat to the normal homeostatic mechanisms that maintain postural stability is superimposed on underlying age-related declines in balance, ambulation, and cardiovascular function. This factor may be an acute illness (eg, fever, water loss, arrhythmia, a new medication, an environmental stress (eg, unfamiliar surrounding, or an unsafe walking surface. The elderly person can not cope with happened additional stress. To prevent and decrease the frequency of falls, effective approaches are medical interventions, environmental modifications, education-exercise programs, and assisted device. Detection and amelioration of risk factors can significantly reduce the rate of future falls. The assessment of fall, causing mobility restriction, use of nursing home, and

  3. Anxiety disorders and falls among older adults.

    Science.gov (United States)

    Holloway, K L; Williams, L J; Brennan-Olsen, S L; Morse, A G; Kotowicz, M A; Nicholson, G C; Pasco, J A

    2016-11-15

    Falls are common among older adults and can lead to serious injuries, including fractures. We aimed to determine associations between anxiety disorders and falls in older adults. Participants were 487 men and 376 women aged ≥60 years enrolled in the Geelong Osteoporosis Study, Australia. Using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Non-patient edition (SCID-I/NP), lifetime history of anxiety disorders was determined. Falls were determined by self-report. In men, a falls-risk score (Elderly Falls Screening Test (EFST)) was also calculated. Among fallers, 24 of 299 (8.0%) had a lifetime history of anxiety disorder compared to 36 of 634 (5.7%) non-fallers (p=0.014). Examination of the association between anxiety and falls suggested differential relationships for men and women. In men, following adjustment for psychotropic medications, mobility and blood pressure, lifetime anxiety disorder was associated with falling (OR 2.96; 95%CI 1.07-8.21) and with EFST score (OR 3.46; 95%CI 1.13-10.6). In women, an association between lifetime anxiety disorder and falls was explained by psychotropic medication use, poor mobility and socioeconomic status. Sub-group analyses involving types of anxiety and anxiety disorders over the past 12-months were not performed due to power limitations. Although anxiety disorders were independently associated with a 3-fold increase in likelihood of reported falls and high falls risk among men, an independent association was not detected among women. These results may aid in prevention of falls through specific interventions aimed at reducing anxiety, particularly in men. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Dance movement therapy and falls prevention.

    Science.gov (United States)

    Veronese, Nicola; Maggi, Stefania; Schofield, Patricia; Stubbs, Brendon

    2017-08-01

    Falls are a leading cause of morbidity, healthcare use and mortality. Dance is a popular form of physical activity among older people and previous research has suggested that it may improve various health outcomes in this population, including balance, gait and muscle performance. A systematic review of the potential benefits of dance on falls and fear of falling is lacking. Thus, we conducted a systematic review considering all randomized controls trials (RCTs) investigating if dance can reduce falls and improve fear of falling in older adults. Major databases were searched from inception until 1 March 2017 and a total of 10 RCTs were identified, which included a total of 680 people (n=356 dance, n=324 control). Overall, the mean age of the samples was 69.4 years, and 75.2% were female. Across four RCTs, dance therapy reduced falls versus usual care in only one study. Dance therapy improved fear of falling in two out of three included RCTs. There were no serious adverse events reported in the RCTs. In summary, we found a paucity of studies investigating the effect of dance on falls and fear of falling and the evidence base is preliminary and equivocal. Given the heterogeneity of the included samples and interventions, in addition to the short-term follow-up, no firm conclusions can be drawn. However, dance appears to be safe and, given its popularity and demonstrated benefits on other health/wellbeing outcomes in older adults, it is important that future research considers its potential benefits on falls/fear of falling in older age. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Quaternary allostratigraphy of surficial deposit map units at Yucca Mountain, Nevada: A progress report

    International Nuclear Information System (INIS)

    Lundstrom, S.C.; Wesling, J.R.; Swan, F.H.; Taylor, E.M.; Whitney, J.W.

    1993-01-01

    Surficial geologic mapping at Yucca Mountain, Nevada, is relevant to site characterization studies of paleoclimate, tectonics, erosion, flood hazards, and water infiltration. Alluvial, colluvial, and eolian allostratigraphic map units are defined on the basis of age-related surface characteristics and soil development, as well as lithology and sedimentology indicative of provenance and depositional mode. In gravelly alluvial units, which include interbedded debris flows, the authors observe a useful qualitative correlation between surface and soil properties. Map units of estimated middle Pleistocene age typically have a well-developed, varnished desert pavement, and minimal erosional and preserved depositional microrelief, associated with a soil with a reddened Bt horizon and stage 3 carbonate and silica morphology. Older units have greater erosional relief, an eroded argillic horizon and stage 4 carbonate morphology, whereas younger units have greater preservation of depositional morphology, but lack well-developed pavements, rock varnish, and Bt and Kqm soil horizons. Trench and gully-wall exposures show that alluvial, colluvial and eolian dominated surface units are underlain by multiple buried soils separating sedimentologically similar deposits; this stratigraphy increases the potential for understanding the long-term Quaternary paleoenvironmental history of Yucca Mountain. Age estimates for allostratigraphic units, presently based on uranium-trend dating and regional correlation using soil development, will be further constrained by ongoing dating studies that include tephra identification, uranium-series disequilibrium, and thermoluminescence methods

  6. Two coarse pyroclastic flow deposits, northern Mono-Inyo Craters, CA

    Science.gov (United States)

    Dennen, R. L.; Bursik, M. I.; Stokes, P. J.; Lagamba, M.; Fontanella, N.; Hintz, A. R.; Jayko, A. S.

    2010-12-01

    The ~1350 A.D., rhyolitic North Mono eruption, Mono-Inyo Craters, CA, included the extrusion and destruction of Panum Dome and associated clastic deposits. Overlying the tephras of the North Mono sequence, the Panum deposits include a block-and-ash flow (BAF) deposit, covering ~3.5 km2. Blocks within the deposit are typically lithic rhyolite and banded gray micro-vesicular glass, showing white, almost powdery marks ranging from circular to linear in shape. These marks are interpreted as friction marks resulting from collisions between clasts. The deposit also contains bread-crusted obsidians with pressed-in clasts as well as reticulite with a bread-crusted surface texture. Near the centerline of the deposit is a ridge-topping train of jigsaw fractured blocks, often with reddish-orange alteration. One house sized jigsaw block sits upstream of a long, thinning pile of reddish orange debris; this “flow shadow” indicates that the block remained relatively stationary while the block and ash flow continued to propagate around it. The bread-crusted reticulite is most common at proximal localities. It is proposed that the dome destruction included a debris avalanche emplacing the train of jigsaw fractured blocks and creating a topographic high, the block-and-ash flow (the farthest reaching deposit from this event) which flowed around the debris avalanche deposits, and a final “lateral expansion” of a magma foam, creating the reticulite seen concentrated at proximal locations. Another coarse pyroclastic flow (here termed the “lower blast deposit”) underlies the North Mono tephra. It is more obsidian rich and finer grained than the Panum BAF. The lower blast deposit may have originated from Pumice Pit vent, which is now capped with an older dome ~0.5 km southeast of Panum. The lower blast deposit extends farther from the Panum vent than does the Panum BAF deposit, and apparently was mistaken for the Panum BAF deposit by previous workers. Hence the run

  7. Falling films on flexible inclines

    Science.gov (United States)

    Matar, O. K.; Craster, R. V.; Kumar, S.

    2007-11-01

    The nonlinear stability and dynamic behavior of falling fluid films is studied for flow over a flexible substrate. We use asymptotic methods to deduce governing equations valid in various limits. Long-wave theory is used to derive Benney-like coupled equations for the film thickness and substrate deflection. Weakly nonlinear equations are then derived from these equations that, in the limit of large wall damping and/or large wall tension, reduce to the Kuramoto-Sivashinsky equation. These models break down when inertia becomes more significant, so we also use a long-wave approximation in conjunction with integral theory to derive three strongly coupled nonlinear evolution equations for the film thickness, substrate deflection, and film volumetric flow rate valid at higher Reynolds numbers. These equations, accounting for inertia, capillary, viscous, wall tension, and damping effects, are solved over a wide range of parameters. Our results suggest that decreasing wall damping and/or wall tension can promote the development of chaos in the weakly nonlinear regime and lead to severe substrate deformations in the strongly nonlinear regime; these can give rise to situations in which the free surface and underlying substrate come into contact in finite time.

  8. Falling into Salvation in Cioran

    Directory of Open Access Journals (Sweden)

    Joseph Acquisto

    2014-01-01

    Full Text Available While, at first glance, there seems to be very little room in the thought of E.M. Cioran for the notion of salvation, a closer look reveals that Cioran returns constantly to the vocabulary and the concept of redemption. This article teases out Cioran’s complex use of the topos of salvation throughout his works, with special emphasis on his middle period. I begin by tracing Cioran’s notion of humanity’s fall into time and language, from which he claims there can be no salvation in the traditional Christian sense. Nonetheless, he retains the concept, claiming at various points that there is a kind of salvation to be found in suicide, music, silence, and skepticism. Ultimately, however, each of these provides only false salvation, since the only permanent solution to the problem of existence for Cioran would be either to cease to exist or to lose our human nature in exchange for a plant-like life. Since this is impossible, we are left with our human means of seeking deliverance. While Cioran generally condemns human attempts at creation or procreation, he takes a different approach to the act of writing. In his reflections on writing we see that salvation for Cioran is always temporary, provisional, and threatened by our next bout of lucidity, but at the same time, eternally renewable with each new act of writing.

  9. Klamath Falls geothermal field, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.; Culver, G.; Lund, J.W.

    1989-09-01

    Klamath Falls, Oregon, is located in a Known Geothermal Resource Area which has been used by residents, principally to obtain geothermal fluids for space heating, at least since the turn of the century. Over 500 shallow-depth wells ranging from 90 to 2,000 ft (27 to 610 m) in depth are used to heat (35 MWt) over 600 structures. This utilization includes the heating of homes, apartments, schools, commercial buildings, hospital, county jail, YMCA, and swimming pools by individual wells and three district heating systems. Geothermal well temperatures range from 100 to 230{degree}F (38 to 110{degree}C) and the most common practice is to use downhole heat exchangers with city water as the circulating fluid. Larger facilities and district heating systems use lineshaft vertical turbine pumps and plate heat exchangers. Well water chemistry indicates approximately 800 ppM dissolved solids, with sodium sulfate having the highest concentration. Some scaling and corrosion does occur on the downhole heat exchangers (black iron pipe) and on heating systems where the geo-fluid is used directly. 73 refs., 49 figs., 6 tabs.

  10. Nuclear winter or nuclear fall?

    Science.gov (United States)

    Berger, André

    Climate is universal. If a major modern nuclear war (i.e., with a large number of small-yield weapons) were to happen, it is not even necessary to have a specific part of the world directly involved for there to be cause to worry about the consequences for its inhabitants and their future. Indeed, smoke from fires ignited by the nuclear explosions would be transported by winds all over the world, causing dark and cold. According to the first study, by Turco et al. [1983], air surface temperature over continental areas of the northern mid-latitudes (assumed to be the nuclear war theatre) would fall to winter levels even in summer (hence the term “nuclear winter”) and induce drastic climatic conditions for several months at least. The devastating effects of a nuclear war would thus last much longer than was assumed initially. Discussing to what extent these estimations of long-term impacts on climate are reliable is the purpose of this article.

  11. A Successful ED Fall Risk Program Using the KINDER 1 Fall RiskAssessment Tool.

    Science.gov (United States)

    Townsend, Ann B; Valle-Ortiz, Marisol; Sansweet, Tracy

    2016-11-01

    Emergency nurses did not perform falls risk assessments routinely on our ED patients; the instrument used was aimed at inpatients. We identified a need to revise fall assessment practices specific to our emergency department. The purpose of the performance improvement project was to reduce ED falls and evaluate the use of an ED-specific fall risk tool, the KINDER 1 Fall Risk Assessment. The plan was to establish fall risk assessment practices at point of ED entry and to decrease total falls. We retrospectively reviewed ED fall data for each quarter of 2013, which included risk assessments scores, the total number of falls, and the circumstances of each fall. Using Kotter's framework to guide a successful change process, we implemented the KINDER 1 to assess fall risk. During the first 4 weeks of the project, 937 patients (27%) were identified as high risk for falls using the KINDER 1. During the subsequent 3 quarters, the total number of falls decreased; reported falls without injuries dropped from 0.21 to 0.07 per 1000 patients, and falls with injuries were reduced from 0.21 to 0.0 per 1000 patients. The results of this project represented a valuable step toward achieving our goal to keep ED patients safe from injuries as a result of falls. The findings add to the body of nursing knowledge on the application of clinical-based performance improvement projects to improve patient outcomes and to provide data on the use of the KINDER 1 tool, which has not been extensively tested. Copyright © 2016 Emergency Nurses Association. Published by Elsevier Inc. All rights reserved.

  12. How Fast Does a Building Fall?

    Science.gov (United States)

    Denny, Mark

    2010-01-01

    In this paper, the time required for a tower block to collapse is calculated. The tower collapses progressively, with one floor falling onto the floor below, causing it to fall. The rate of collapse is found to be not much slower than freefall. The calculation is an engaging and relevant application of Newton's laws, suitable for undergraduate…

  13. Free Fall and the Equivalence Principle Revisited

    Science.gov (United States)

    Pendrill, Ann-Marie

    2017-01-01

    Free fall is commonly discussed as an example of the equivalence principle, in the context of a homogeneous gravitational field, which is a reasonable approximation for small test masses falling moderate distances. Newton's law of gravity provides a generalisation to larger distances, and also brings in an inhomogeneity in the gravitational field.…

  14. Falls from height: A retrospective analysis.

    Science.gov (United States)

    Turgut, Kasim; Sarihan, Mehmet Ediz; Colak, Cemil; Güven, Taner; Gür, Ali; Gürbüz, Sükrü

    2018-01-01

    Emergency services manage trauma patients frequently and falls from height comprise the main cause of emergency service admissions. In this study, we aimed to analyse the demographic characteristics of falls from height and their relationship to the mortality. A total of 460 patients, who admitted to the Emergency Department of Inonu University between November 2011 and November 2014 with a history of fall from height, were examined retrospectively. Demographic parameters, fall characteristics and their effect to mortality were evaluated statistically. The study comprised of 292 (63.5%) men and 168 (36.5%) women patients. The mean age of all patients was 27±24.99 years. Twenty-six (5.6%) patients died and the majority of them were in ≥62 years old group. The highest percentage of falls was at 0-5 years age group (28.3%). People fell mainly from 1.1-4 metres(m) level (46.1%). The causes of falls were ordered as unintentional (92.2%), workplace (8.1%) and suicidal (1.7%). Skin and soft tissue injuries (37.4%) were the main traumatic lesions. Age, fall height, fall place, lineer skull fracture, subarachnoidal hemorrhage, cervical fracture, thoracic vertebra fracture and trauma scores had statistically significant effect on mortality. The casualties died because of subarachnoid hemorrhage mostly.

  15. Fall prevention strategy in an emergency department.

    Science.gov (United States)

    Muray, Mwali; Bélanger, Charles H; Razmak, Jamil

    2018-02-12

    Purpose The purpose of this paper is to document the need for implementing a fall prevention strategy in an emergency department (ED). The paper also spells out the research process that led to approving an assessment tool for use in hospital outpatient services. Design/methodology/approach The fall risk assessment tool was based on the Morse Fall Scale. Gender mix and age above 65 and 80 years were assessed on six risk assessment variables using χ 2 analyses. A logistic regression analysis and model were used to test predictor strength and relationships among variables. Findings In total, 5,371 (56.5 percent) geriatric outpatients were deemed to be at fall risk during the study. Women have a higher falls incidence in young and old age categories. Being on medications for patients above 80 years exposed both genders to equal fall risks. Regression analysis explained 73-98 percent of the variance in the six-variable tool. Originality/value Canadian quality and safe healthcare accreditation standards require that hospital staff develop and adhere to fall prevention policies. Anticipated physiological falls can be prevented by healthcare interventions, particularly with older people known to bear higher risk factors. An aging population is increasing healthcare volumes and medical challenges. Precautionary measures for patients with a vulnerable cognitive and physical status are essential for quality care.

  16. Disproportion in the falling birth rate.

    Science.gov (United States)

    Gordon, R R

    1977-10-08

    Since 1962 there has been a disproportionately greater fall in the number of small (less than 1000 g) live births than total live births: this has applied to Sheffield and to England and Wales but more to the former. This may have affected falling neonatal mortality rates.

  17. Osteosarcopenic obesity and fall prevention strategies.

    Science.gov (United States)

    Hita-Contreras, Fidel; Martínez-Amat, Antonio; Cruz-Díaz, David; Pérez-López, Faustino R

    2015-02-01

    Sarcopenia, obesity, and osteoporosis are three interrelated entities which may share common pathophysiological factors. In the last decades, overall survival has drastically increased. Postmenopausal women, due to their estrogen depletion, are at higher risk of developing any of these three conditions or the three, which is termed osteosarcopenic obesity. One of the most common health problems among these patients is the elevated risk of falls and fractures. Falls and fall-related injuries are one of the major causes of mortality and morbidity in older adults, and have a significant impact on social, economical and health-related costs. Several extrinsic and intrinsic risk factors have been described that play a role in the etiology of falls. A therapeutic approach to osteosarcopenic obesity aimed at the prevention of falls must include several factors, and act on those risk elements which can be effectively modified. An adequate weight-loss diet and a good nutritional intake, with an appropriate amount of vitamin D and the right protein/carbohydrates ratio, may contribute to the prevention of falls. The recommendation of physical exercise, both traditional (resistance or aerobic training) and more recent varieties (Tai Chi, Pilates, body vibration), can improve balance and positively contribute to fall prevention, whether by itself or in combination with other therapeutic strategies. Finally, a pharmacological approach, especially one focused on hormone therapy, has shown to have a positive effect on postmenopausal women's balance, leading to a decreased risk of falls. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Nurses' Job Satisfaction and Patient Falls

    Directory of Open Access Journals (Sweden)

    Cecilia D. Alvarez, DNP, RN

    2007-09-01

    Results and Conclusion: No significant relationship was found between overall nurses' job satisfaction and patient fall rate. MD–RN interactions (r = .65 and decision-making (r = .57 were the job satisfaction subscales that showed a significant positive correlation with patient fall rate (p < .05. Recommendations for future research are provided.

  19. Risk factors for falls of older citizens

    NARCIS (Netherlands)

    Boelens, C.; Hekman, E. E. G.; Verkerke, G. J.

    2013-01-01

    OBJECTIVE: Fall prevention is a major issue in the ageing society. This study provides an overview of all risk factors for falls of older citizens. METHOD: A literature search was conducted to retrieve studies of the past 25 years. All participants from the studies lived in the community or

  20. On free fall of a relativistic particle

    International Nuclear Information System (INIS)

    Chernikov, N.A.; Paramonova, N.N.; Shavokhina, N.S.

    2005-01-01

    The free fall of a relativistic particle is considered: the well-known fact of the light velocity constancy is taken into account in the Galilean problem about the movement of a particle from nongravitational forces and its fall onto the ground. The velocity hodograph and the world line of the particle are found

  1. Exploring Older Adult ED Fall Patients' Understanding of Their Fall: A Qualitative Study.

    Science.gov (United States)

    Shankar, Kalpana N; Taylor, Devon; Rizzo, Caroline T; Liu, Shan W

    2017-12-01

    We sought to understand older patients' perspectives about their fall, fall risk factors, and attitude toward emergency department (ED) fall-prevention interventions. We conducted semistructured interviews between July 2015 and January 2016 of community-dwelling, nondemented patients in the ED, who presented with a fall to an urban, teaching hospital. Interviews were halted once we achieve thematic saturation with the data coded and categorized into themes. Of the 63 patients interviewed, patients blamed falls on the environment, accidents, a medical condition, or themselves. Three major themes were generated: (1) patients blamed falls on a multitude of things but never acknowledged a possible multifactorial rationale, (2) patients have variable level of concerns regarding their current fall and future fall risk, and (3) patients demonstrated a range of receptiveness to ED interventions aimed at preventing falls but provided little input as to what those interventions should be. Many older patients who fall do not understand their fall risk. However, based on the responses provided, older adults tend to be more receptive to intervention and more concerned about their future fall risk, making the ED an appropriate setting for intervention.

  2. Characteristics of daily life gait in fall and non fall-prone stroke survivors and controls

    NARCIS (Netherlands)

    Mirjam Pijnappels; Sjoerd M. Bruijn; Kimberley M. Schooten; Jaap H. van Dieën; Dr. H.M. Wittink; Michiel Punt

    2016-01-01

    Background: Falls in stroke survivors can lead to serious injuries and medical costs. Fall risk in older adults can be predicted based on gait characteristics measured in daily life. Given the different gait patterns that stroke survivors exhibit it is unclear whether a similar fall-prediction model

  3. [Fear of falling in a fall clinic for geriatric patients: a pilot study

    NARCIS (Netherlands)

    Dautzenberg, P.LJ.; Buurman, B.H.; Loonen, A.J.; Wouters, C.J.; Olde Rikkert, M.G.M.

    2005-01-01

    OBJECTIVE: In this pilot study we want to determine how often fear of falling occurs in geriatric patients visiting a fall clinic and to study the characteristics of fear of falling and its consequences. DESIGN: Retrospective study of patient's records. METHOD: A random sample of 100 medical records

  4. Prospective study of falls and risk factors for falls in adults with advanced cancer.

    LENUS (Irish Health Repository)

    Stone, Carol A

    2012-06-10

    Retrospective studies of inpatients with cancer suggest that a cancer diagnosis confers a high risk of falls. In adults with advanced cancer, we aimed to prospectively document the incidence of falls, identify the risk factors, and determine if falls in this population occur predominantly in older patients.

  5. Fall Detection Using Smartphone Audio Features.

    Science.gov (United States)

    Cheffena, Michael

    2016-07-01

    An automated fall detection system based on smartphone audio features is developed. The spectrogram, mel frequency cepstral coefficents (MFCCs), linear predictive coding (LPC), and matching pursuit (MP) features of different fall and no-fall sound events are extracted from experimental data. Based on the extracted audio features, four different machine learning classifiers: k-nearest neighbor classifier (k-NN), support vector machine (SVM), least squares method (LSM), and artificial neural network (ANN) are investigated for distinguishing between fall and no-fall events. For each audio feature, the performance of each classifier in terms of sensitivity, specificity, accuracy, and computational complexity is evaluated. The best performance is achieved using spectrogram features with ANN classifier with sensitivity, specificity, and accuracy all above 98%. The classifier also has acceptable computational requirement for training and testing. The system is applicable in home environments where the phone is placed in the vicinity of the user.

  6. Economical Atomic Layer Deposition

    Science.gov (United States)

    Wyman, Richard; Davis, Robert; Linford, Matthew

    2010-10-01

    Atomic Layer Deposition is a self limiting deposition process that can produce films at a user specified height. At BYU we have designed a low cost and automated atomic layer deposition system. We have used the system to deposit silicon dioxide at room temperature using silicon tetrachloride and tetramethyl orthosilicate. Basics of atomic layer deposition, the system set up, automation techniques and our system's characterization are discussed.

  7. Effect of a Multidisciplinary Fall Risk Assessment on Falls Among Neurology Inpatients

    Science.gov (United States)

    Hunderfund, Andrea N. Leep; Sweeney, Cynthia M.; Mandrekar, Jayawant N.; Johnson, LeAnn M.; Britton, Jeffrey W.

    2011-01-01

    OBJECTIVE: To evaluate whether the addition of a physician assessment of patient fall risk at admission would reduce inpatient falls on a tertiary hospital neurology inpatient unit. PATIENTS AND METHODS: A physician fall risk assessment was added to the existing risk assessment process (clinical nurse evaluation and Hendrich II Fall Risk Model score with specific fall prevention measures for patients at risk). An order to select either “Patient is” or “Patient is not at high risk of falls by physician assessment” was added to the physician electronic admission order set. Nurses and physicians were instructed to reach consensus when assessments differed. Full implementation occurred in second-quarter 2008. Preimplementation (January 1, 2006, to March 31, 2008) and postimplementation (April 1, 2008, to December 31, 2009) rates of falls were compared on the neurology inpatient unit and on 6 other medical units that did not receive intervention. RESULTS: The rate of falls during the 7 quarters after full implementation was significantly lower than that during the 9 preceding quarters (4.12 vs 5.69 falls per 1000 patient-days; P=.04), whereas the rate of falls on other medical units did not significantly change (2.99 vs 3.33 falls per 1000 patient-days; P=.24, Poisson test). The consensus risk assessment at admission correctly identified patients at risk for falls (14/325 at-risk patients fell vs 0/147 low-risk patients; P=.01, χ2 test), but the Hendrich II Fall Risk Model score, nurse, and physician assessments individually did not. CONCLUSION: A multidisciplinary approach to fall risk assessment is feasible, correctly identifies patients at risk, and was associated with a reduction in inpatient falls. PMID:21193651

  8. Falls and falls efficacy: the role of sustained attention in older adults

    LENUS (Irish Health Repository)

    O'Halloran, Aisling M

    2011-12-19

    Abstract Background Previous evidence indicates that older people allocate more of their attentional resources toward their gait and that the attention-related changes that occur during aging increase the risk of falls. The aim of this study was to investigate whether performance and variability in sustained attention is associated with falls and falls efficacy in older adults. Methods 458 community-dwelling adults aged ≥ 60 years underwent a comprehensive geriatric assessment. Mean and variability of reaction time (RT), commission errors and omission errors were recorded during a fixed version of the Sustained Attention to Response Task (SART). RT variability was decomposed using the Fast Fourier Transform (FFT) procedure, to help characterise variability associated with the arousal and vigilance aspects of sustained attention. The number of self-reported falls in the previous twelve months, and falls efficacy (Modified Falls Efficacy Scale) were also recorded. Results Significant increases in the mean and variability of reaction time on the SART were significantly associated with both falls (p < 0.01) and reduced falls efficacy (p < 0.05) in older adults. An increase in omission errors was also associated with falls (p < 0.01) and reduced falls efficacy (p < 0.05). Upon controlling for age and gender affects, logistic regression modelling revealed that increasing variability associated with the vigilance (top-down) aspect of sustained attention was a retrospective predictor of falling (p < 0.01, OR = 1.14, 95% CI: 1.03 - 1.26) in the previous year and was weakly correlated with reduced falls efficacy in non-fallers (p = 0.07). Conclusions Greater variability in sustained attention is strongly correlated with retrospective falls and to a lesser degree with reduced falls efficacy. This cognitive measure may provide a novel and valuable biomarker for falls in older adults, potentially allowing for early detection and the implementation of preventative intervention

  9. Falls efficacy, postural balance, and risk for falls in older adults with falls-related emergency department visits: prospective cohort study.

    Science.gov (United States)

    Pua, Yong-Hao; Ong, Peck-Hoon; Clark, Ross Allan; Matcher, David B; Lim, Edwin Choon-Wyn

    2017-12-21

    Risk for falls in older adults has been associated with falls efficacy (self-perceived confidence in performing daily physical activities) and postural balance, but available evidence is limited and mixed. We examined the interaction between falls efficacy and postural balance and its association with future falls. We also investigated the association between falls efficacy and gait decline. Falls efficacy, measured by the Modified Falls Efficacy Scale (MFES), and standing postural balance, measured using computerized posturography on a balance board, were obtained from 247 older adults with a falls-related emergency department visit. Six-month prospective fall rate and habitual gait speed at 6 months post baseline assessment were also measured. In multivariable proportional odds analyses adjusted for potential confounders, falls efficacy modified the association between postural balance and fall risk (interaction P = 0.014): increasing falls efficacy accentuated the increased fall risk related to poor postural balance. Low baseline falls efficacy was strongly predictive of worse gait speed (0.11 m/s [0.06 to 0.16] slower gait speed per IQR decrease in MFES; P falls efficacy but poor postural balance were at greater risk for falls than those with low falls efficacy; however, low baseline falls efficacy was strongly associated with worse gait function at follow-up. Further research into these subgroups of older adults is warranted. ClinicalTrials.gov identifier: NCT01713543 .

  10. Optimal fall indicators for slip induced falls on a cross-slope.

    Science.gov (United States)

    Domone, Sarah; Lawrence, Daniel; Heller, Ben; Hendra, Tim; Mawson, Sue; Wheat, Jonathan

    2016-08-01

    Slip-induced falls are among the most common cause of major occupational injuries in the UK as well as being a major public health concern in the elderly population. This study aimed to determine the optimal fall indicators for fall detection models which could be used to reduce the detrimental consequences of falls. A total of 264 kinematic variables covering three-dimensional full body model translation and rotational measures were analysed during normal walking, successful recovery from slips and falls on a cross-slope. Large effect sizes were found for three kinematic variables which were able to distinguish falls from normal walking and successful recovery. Further work should consider other types of daily living activities as results show that the optimal kinematic fall indicators can vary considerably between movement types. Practitioner Summary: Fall detection models are used to minimise the adverse consequences of slip-induced falls, a major public health concern. Optimal fall indicators were derived from a comprehensive set of kinematic variables for slips on a cross-slope. Results suggest robust detection of falls is possible on a cross-slope but may be more difficult than level walking.

  11. Falls and fear of falling in vertigo and balance disorders: A controlled cross-sectional study.

    Science.gov (United States)

    Schlick, Cornelia; Schniepp, Roman; Loidl, Verena; Wuehr, Max; Hesselbarth, Kristin; Jahn, Klaus

    2016-01-01

    Vertigo and dizziness are among the most prevalent symptoms in neurologic disorders. Although many of these patients suffer from postural instability and gait disturbances, there is only limited data on their risk of falling. We conducted a controlled cross-sectional study at the tertiary care outpatient clinic of the German Center for Vertigo and Balance Disorders using a self-administered questionnaire to assess falls, fall-related injuries, and fear of falling. The recruitment period was 6 months. A total of 569 patients (mean age 59.6 ± 17.1 years, 55% females) and 100 healthy participants were included (response rate > 90%). Dizzy patients with central balance disorders (Parkinsonian, cerebellar, and brainstem oculomotor syndromes) had the highest fall rates (> 50% recurrent fallers, odds ratio > 10). The rate of recurrent fallers was 30% in bilateral vestibular failure and peripheral neuropathy (odds ratio > 5). Patients with functional dizziness (somatoform or phobic vertigo) were concerned about falling but did not fall more often than healthy controls (odds ratio 0.87). Falls are common in patients presenting to a dizziness unit. Those with central syndromes are at risk of recurrent and injurious falling. Fall rates and fear of falling should be assessed in balance disorders and used to guide the regimen of rehabilitation therapy. The identification of risk factors would help provide protective measures to these groups of patients.

  12. Predictive value of stabilometry and fear of falling on falls in postmenopausal women.

    Science.gov (United States)

    Hita-Contreras, F; Martínez-Amat, A; Lomas-Vega, R; Álvarez, P; Aránega, A; Martínez-López, E; Mendoza, N

    2013-10-01

    Falls are one of the leading causes of fractures and impaired quality of life in the elderly, and they are related to balance deficit and to fear of falls. The purpose of our study is to evaluate predictors of falls in the 50-65-year-old postmenopausal population. A prospective cohort study was conducted on 96 postmenopausal women. Fear of falling and postural stability were assessed by using the FES-I (Falls Efficacy Scale-International) and a force platform, respectively. Fall frequency was determined in the 12-month follow-up study period. Multivariate logistic regression was used to identify predictive factors of falls. Fear of falls, the FES-I scale and four stabilometric parameters, specifically under eyes-closed condition, were significantly higher in the group of fallers. The root mean square amplitude in the medial-lateral direction with eyes closed (RMSXec) (odds ratio 5.1, 95% confidence interval (CI) 1.6-15.5, p = 0.004) and FES-I (odds ratio 3.4, 95% CI 1.1-10.5, p = 0.026) were the best independent predictive factors of the risk of falling. RMSXec > 0.133 was the best predictive factor for falls in our group of 50-65-year-old postmenopausal women studied, and a FES-I score > 20 could predict falls in this population.

  13. Constructing a reference tephrochronology for Augustine Volcano, Alaska

    Science.gov (United States)

    Wallace, Kristi; Coombs, Michelle L.

    2013-01-01

    Augustine Volcano is the most historically active volcano in Alaska's populous Cook Inlet region. Past on-island work on pre-historic tephra deposits mainly focused on using tephra layers as markers to help distinguish among prevalent debris-avalanche deposits on the island (Waitt and Beget, 2009, USGS Prof Paper 1762), or as source material for petrogenetic studies. No comprehensive reference study of tephra fall from Augustine Volcano previously existed. Numerous workers have identified Holocene-age tephra layers in the region surrounding Augustine Island, but without well-characterized reference deposits, correlation back to the source volcano is difficult. The purpose of this detailed tephra study is to provide a record of eruption frequency and magnitude, as well as to elucidate physical and chemical characteristics for use as reference standards for comparison with regionally distributed Augustine tephra layers. Whole rock major- and trace-element geochemistry, deposit componentry, and field context are used to correlate tephra units on the island where deposits are coarse grained. Major-element glass geochemistry was collected for use in correlating to unknown regional tephra. Due to the small size of the volcanic island (9 by 11 km in diameter) and frequent eruptive activity, on-island exposures of tephra deposits older than a couple thousand years are sparse, and the lettered Tephras B, M, C, H, I, and G of Waitt and Beget (2009) range in age from 370-2200 yrs B.P. There are, however, a few exposures on the south side of the volcano, within about 2 km of the vent, where stratigraphic sections that extend back to the late Pleistocene glaciation include coarse pumice-fall deposits. We have linked the letter-named tephras from the coast to these higher exposures on the south side using physical and chemical characteristics of the deposits. In addition, these exposures preserve at least 5 older major post-glacial eruptions of Augustine. These ultra

  14. Preclinical Alzheimer disease and risk of falls.

    Science.gov (United States)

    Stark, Susan L; Roe, Catherine M; Grant, Elizabeth A; Hollingsworth, Holly; Benzinger, Tammie L; Fagan, Anne M; Buckles, Virginia D; Morris, John C

    2013-07-30

    We determined the rate of falls among cognitively normal, community-dwelling older adults, some of whom had presumptive preclinical Alzheimer disease (AD) as detected by in vivo imaging of fibrillar amyloid plaques using Pittsburgh compound B (PiB) and PET and/or by assays of CSF to identify Aβ₄₂, tau, and phosphorylated tau. We conducted a 12-month prospective cohort study to examine the cumulative incidence of falls. Participants were evaluated clinically and underwent PiB PET imaging and lumbar puncture. Falls were reported monthly using an individualized calendar journal returned by mail. A Cox proportional hazards model was used to test whether time to first fall was associated with each biomarker and the ratio of CSF tau/Aβ₄₂ and CSF phosphorylated tau/Aβ₄₂, after adjustment for common fall risk factors. The sample (n = 125) was predominately female (62.4%) and white (96%) with a mean age of 74.4 years. When controlled for ability to perform activities of daily living, higher levels of PiB retention (hazard ratio = 2.95 [95% confidence interval 1.01-6.45], p = 0.05) and of CSF biomarker ratios (p risk factor for falls in older adults. This study suggests that subtle noncognitive changes that predispose older adults to falls are associated with AD and may precede detectable cognitive changes.

  15. Pathogenesis and treatment of falls in elderly

    Science.gov (United States)

    Pasquetti, Pietro; Apicella, Lorenzo; Mangone, Giuseppe

    2014-01-01

    Summary Falls in the elderly are a public health problem. Consequences of falls are increased risk of hospitalization, which results in an increase in health care costs. It is estimated that 33% of individuals older than 65 years undergoes falls. Causes of falls can be distinguished in intrinsic and extrinsic predisposing conditions. The intrinsic causes can be divided into age-related physiological changes and pathological predisposing conditions. The age-related physiological changes are sight disorders, hearing disorders, alterations in the Central Nervous System, balance deficits, musculoskeletal alterations. The pathological conditions can be Neurological, Cardiovascular, Endocrine, Psychiatric, Iatrogenic. Extrinsic causes of falling are environmental factors such as obstacles, inadequate footwear. The treatment of falls must be multidimensional and multidisciplinary. The best instrument in evaluating elderly at risk is Comprehensive Geriatric Assessment (CGA). CGA allows better management resulting in reduced costs. The treatment should be primarily preventive acting on extrinsic causes; then treatment of chronic and acute diseases. Rehabilitation is fundamental, in order to improve residual capacity, motor skills, postural control, recovery of strength. There are two main types of exercises: aerobic and muscular strength training. Education of patient is a key-point, in particular through the Back School. In conclusion falls in the elderly are presented as a “geriatric syndrome”; through a multidimensional assessment, an integrated treatment and a rehabilitation program is possible to improve quality of life in elderly. PMID:25568657

  16. Neuropsychological Mechanisms for Falls in Older Adults

    Directory of Open Access Journals (Sweden)

    Yu eLiu

    2014-04-01

    Full Text Available Falls, a common cause of injury among older adults, have become increasingly prevalent. As the world’s population ages, the increase in – and the prevalence of – falls among older people makes this a serious and compelling societal and healthcare issue. Physical weakness is a critical predictor in falling. While considerable research has examined this relationship, comprehensive reviews of neuropsychological predictors of falls have been lacking. In this paper, we examine and discuss current studies of the neuropsychological predictors of falls in older adults, as related to sporting and non-sporting contexts. By integrating the existing evidence, we propose that brain aging is an important precursor of the increased risk of falls in older adults. Brain aging disrupts the neural integrity of motor outputs and reduces neuropsychological abilities. Older adults may shift from unconscious movement control to more conscious or attentive motor control. Increased understanding of the causes of falls will afford opportunities to reduce their incidence, reduce consequent injuries, improve overall well-being and quality of life, and possibly to prolong life.

  17. History of falls, gait, balance, and fall risks in older cancer survivors living in the community.

    Science.gov (United States)

    Huang, Min H; Shilling, Tracy; Miller, Kara A; Smith, Kristin; LaVictoire, Kayle

    2015-01-01

    Older cancer survivors may be predisposed to falls because cancer-related sequelae affect virtually all body systems. The use of a history of falls, gait speed, and balance tests to assess fall risks remains to be investigated in this population. This study examined the relationship of previous falls, gait, and balance with falls in community-dwelling older cancer survivors. At the baseline, demographics, health information, and the history of falls in the past year were obtained through interviewing. Participants performed tests including gait speed, Balance Evaluation Systems Test, and short-version of Activities-specific Balance Confidence scale. Falls were tracked by mailing of monthly reports for 6 months. A "faller" was a person with ≥1 fall during follow-up. Univariate analyses, including independent sample t-tests and Fisher's exact tests, compared baseline demographics, gait speed, and balance between fallers and non-fallers. For univariate analyses, Bonferroni correction was applied for multiple comparisons. Baseline variables with Pfalls with age as covariate. Sensitivity and specificity of each predictor of falls in the model were calculated. Significance level for the regression analysis was Pfalls. Baseline demographics, health information, history of falls, gaits speed, and balance tests did not differ significantly between fallers and non-fallers. Forward logistic regression revealed that a history of falls was a significant predictor of falls in the final model (odds ratio =6.81; 95% confidence interval =1.594-29.074) (Pfalls were 74% and 69%, respectively. Current findings suggested that for community-dwelling older cancer survivors with mixed diagnoses, asking about the history of falls may help detect individuals at risk of falling.

  18. Falls and Fall-Related Injuries among Community-Dwelling Adults in the United States.

    Directory of Open Access Journals (Sweden)

    Santosh K Verma

    Full Text Available Falls are the leading cause of unintentional injuries in the U.S.; however, national estimates for all community-dwelling adults are lacking. This study estimated the national incidence of falls and fall-related injuries among community-dwelling U.S. adults by age and gender and the trends in fall-related injuries across the adult life span.Nationally representative data from the National Health Interview Survey (NHIS 2008 Balance and Dizziness supplement was used to develop national estimates of falls, and pooled data from the NHIS was used to calculate estimates of fall-related injuries in the U.S. and related trends from 2004-2013. Costs of unintentional fall-related injuries were extracted from the CDC's Web-based Injury Statistics Query and Reporting System.Twelve percent of community-dwelling U.S. adults reported falling in the previous year for a total estimate of 80 million falls at a rate of 37.2 falls per 100 person-years. On average, 9.9 million fall-related injuries occurred each year with a rate of 4.38 fall-related injuries per 100 person-years. In the previous three months, 2.0% of older adults (65+, 1.1% of middle-aged adults (45-64 and 0.7% of young adults (18-44 reported a fall-related injury. Of all fall-related injuries among community-dwelling adults, 32.3% occurred among older adults, 35.3% among middle-aged adults and 32.3% among younger adults. The age-adjusted rate of fall-related injuries increased 4% per year among older women (95% CI 1%-7% from 2004 to 2013. Among U.S. adults, the total lifetime cost of annual unintentional fall-related injuries that resulted in a fatality, hospitalization or treatment in an emergency department was 111 billion U.S. dollars in 2010.Falls and fall-related injuries represent a significant health and safety problem for adults of all ages. The findings suggest that adult fall prevention efforts should consider the entire adult lifespan to ensure a greater public health benefit.

  19. Falls and Fall-Related Injuries among Community-Dwelling Adults in the United States

    Science.gov (United States)

    Verma, Santosh K.; Willetts, Joanna L.; Corns, Helen L.; Marucci-Wellman, Helen R.; Lombardi, David A.; Courtney, Theodore K.

    2016-01-01

    Introduction Falls are the leading cause of unintentional injuries in the U.S.; however, national estimates for all community-dwelling adults are lacking. This study estimated the national incidence of falls and fall-related injuries among community-dwelling U.S. adults by age and gender and the trends in fall-related injuries across the adult life span. Methods Nationally representative data from the National Health Interview Survey (NHIS) 2008 Balance and Dizziness supplement was used to develop national estimates of falls, and pooled data from the NHIS was used to calculate estimates of fall-related injuries in the U.S. and related trends from 2004–2013. Costs of unintentional fall-related injuries were extracted from the CDC’s Web-based Injury Statistics Query and Reporting System. Results Twelve percent of community-dwelling U.S. adults reported falling in the previous year for a total estimate of 80 million falls at a rate of 37.2 falls per 100 person-years. On average, 9.9 million fall-related injuries occurred each year with a rate of 4.38 fall-related injuries per 100 person-years. In the previous three months, 2.0% of older adults (65+), 1.1% of middle-aged adults (45–64) and 0.7% of young adults (18–44) reported a fall-related injury. Of all fall-related injuries among community-dwelling adults, 32.3% occurred among older adults, 35.3% among middle-aged adults and 32.3% among younger adults. The age-adjusted rate of fall-related injuries increased 4% per year among older women (95% CI 1%–7%) from 2004 to 2013. Among U.S. adults, the total lifetime cost of annual unintentional fall-related injuries that resulted in a fatality, hospitalization or treatment in an emergency department was 111 billion U.S. dollars in 2010. Conclusions Falls and fall-related injuries represent a significant health and safety problem for adults of all ages. The findings suggest that adult fall prevention efforts should consider the entire adult lifespan to ensure a

  20. Fall from heights: does height really matter?

    Science.gov (United States)

    Alizo, G; Sciarretta, J D; Gibson, S; Muertos, K; Romano, A; Davis, J; Pepe, A

    2018-06-01

    Fall from heights is high energy injuries and constitutes a fraction of all fall-related trauma evaluations while bearing an increase in morbidity and mortality. We hypothesize that despite advancements in trauma care, the overall survivability has not improved in this subset of trauma patients. All adult trauma patients treated after sustaining a fall from heights during a 40-month period were retrospectively reviewed. Admission demographics, clinical data, fall height (ft), injury patterns, ISS, GCS, length of stay, and mortality were reviewed. 116 patients sustained a fall from heights, 90.4% accidental. A mean age of 37± 14.7 years, 86% male, and a fall height of 19 ± 10 ft were encountered. Admission GCS was 13 ± 2 with ISS 10 ± 11. Overall LOS was 6.6 ± 14.9 days and an ICU LOS of 2.8 ± 8.9 days. Falls ≥ 25 ft.(16%) had lower GCS 10.4 ± 5.8, increased ISS 22.6 ± 13.8, a fall height 37.9 ± 13.1 ft and associated increased mortality (p < 0.001). Mortality was 5.2%, a mean distance fallen of 39 ± 22 ft. and an ISS of 31.5 ±16.5. Brain injury was the leading cause of death, 50% with open skull fractures. Level of height fallen is a good predictor of overall outcome and survival. Despite advances in trauma care, death rates remain unchanged. Safety awareness and injury prevention programs are needed to reduce the risk of high-level falls.

  1. Collective Fall Protection for Construction Workers

    Directory of Open Access Journals (Sweden)

    Sulowski, A. C.

    2014-03-01

    Full Text Available Construction safety regulations require protection of workers against falls from elevations. The collective fall protection systems, in most cases, allow workers to move freely without wearing individual fall protection gear. The collective systems which prevent falls are preferred over the fall arrest systems. The latter are employed only if prevention of falls is not feasible. Arresting a fall always carries with it a residual risk of injury to the fall victim. The collective fall arrest systems are employed primarily during construction of electricity or telecomm towers. The aim of this paper has been a review of the collective FPS employed in the construction industry.Las normas de seguridad en la construcción requieren de protección para los trabajadores contra las caídas desde altura. Los Sistemas de Protección contra Caídas (FPS, por sus siglas en inglés colectivos, en la mayoría de los casos, permiten que los trabajadores se muevan libremente sin usar un equipo de protección contra caídas individual. Los sistemas colectivos de prevención de caídas son preferibles a los sistemas de detención de caídas, estos últimos se emplean sólo si la prevención de las caídas no es factible. La detención de una caída siempre lleva consigo un riesgo residual de lesiones en la víctima accidentada. Los sistemas colectivos de detención de caídas se emplean principalmente en la construcción de torres de electricidad o telecomunicaciones. El objetivo de este trabajo ha sido la revisión de los sistemas colectivos de protección contra caídas empleados en la industria de la construcción.

  2. Unexplained Falls Are Frequent in Patients with Fall-Related Injury Admitted to Orthopaedic Wards: The UFO Study (Unexplained Falls in Older Patients).

    Science.gov (United States)

    Chiara, Mussi; Gianluigi, Galizia; Pasquale, Abete; Alessandro, Morrione; Alice, Maraviglia; Gabriele, Noro; Paolo, Cavagnaro; Loredana, Ghirelli; Giovanni, Tava; Franco, Rengo; Giulio, Masotti; Gianfranco, Salvioli; Niccolò, Marchionni; Andrea, Ungar

    2013-01-01

    To evaluate the incidence of unexplained falls in elderly patients affected by fall-related fractures admitted to orthopaedic wards, we recruited 246 consecutive patients older than 65 (mean age 82 ± 7 years, range 65-101). Falls were defined "accidental" (fall explained by a definite accidental cause), "medical" (fall caused directly by a specific medical disease), "dementia-related" (fall in patients affected by moderate-severe dementia), and "unexplained" (nonaccidental falls, not related to a clear medical or drug-induced cause or with no apparent cause). According to the anamnestic features of the event, older patients had a lower tendency to remember the fall. Patients with accidental fall remember more often the event. Unexplained falls were frequent in both groups of age. Accidental falls were more frequent in younger patients, while dementia-related falls were more common in the older ones. Patients with unexplained falls showed a higher number of depressive symptoms. In a multivariate analysis a higher GDS and syncopal spells were independent predictors of unexplained falls. In conclusion, more than one third of all falls in patients hospitalized in orthopaedic wards were unexplained, particularly in patients with depressive symptoms and syncopal spells. The identification of fall causes must be evaluated in older patients with a fall-related injury.

  3. Unexplained Falls Are Frequent in Patients with Fall-Related Injury Admitted to Orthopaedic Wards: The UFO Study (Unexplained Falls in Older Patients

    Directory of Open Access Journals (Sweden)

    Mussi Chiara

    2013-01-01

    Full Text Available To evaluate the incidence of unexplained falls in elderly patients affected by fall-related fractures admitted to orthopaedic wards, we recruited 246 consecutive patients older than 65 (mean age 82±7 years, range 65–101. Falls were defined “accidental” (fall explained by a definite accidental cause, “medical” (fall caused directly by a specific medical disease, “dementia-related” (fall in patients affected by moderate-severe dementia, and “unexplained” (nonaccidental falls, not related to a clear medical or drug-induced cause or with no apparent cause. According to the anamnestic features of the event, older patients had a lower tendency to remember the fall. Patients with accidental fall remember more often the event. Unexplained falls were frequent in both groups of age. Accidental falls were more frequent in younger patients, while dementia-related falls were more common in the older ones. Patients with unexplained falls showed a higher number of depressive symptoms. In a multivariate analysis a higher GDS and syncopal spells were independent predictors of unexplained falls. In conclusion, more than one third of all falls in patients hospitalized in orthopaedic wards were unexplained, particularly in patients with depressive symptoms and syncopal spells. The identification of fall causes must be evaluated in older patients with a fall-related injury.

  4. Geothermal District Heating System City of Klamath Falls

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, Paul J; Rafferty, Kevin

    1991-12-01

    The city of Klamath Falls became interested in the possibility of a establishing geothermal district heating system for downtown government buildings in January 1977. Since that time, the project has undergone some controversial and interesting developments that may be of educational value to other communities contemplating such a project. The purpose and content of this article is to identify the historical development of the project; including the design of the system, well owner objections to the project, aquifer testing, piping failure, and future expansion and marketing incentives. The shallow geothermal reservoir in Klamath falls extends for at least 6.8 miles in a northwest-southeast direction, as shown on Figure 1, with a width of about 2 miles. More than 550 thermal wells ranging in depth from about 10 to 2,000 ft, and obtaining or contacting water from 70 to 230oF, have been drilled into the reservoir. The system is not geologically homogeneous. Great variations in horizontal permeability and many vertical discontinuities exist because of stratigraphy and structure of the area. Basalt flows, eruptive centers, fluvial and lacustrine deposits, diatomite and pyroclastic materials alternate in the rock column. Normal faults with large throw (estimated up to 1,700 ft) are spaced less than 3,300 ft apart and appear to be the main avenue of vertical movement of hot fluids. In order to more effectively utilize this resource, the city of Klamath Falls decided in 1978 to apply for a federal grant (Program Opportunity Notice to cost share field experiment projects) to construct a geothermal district heating system that would deliver geothermal fluids to areas not located on the resource. In 1977, several Geo-Heat Center staff members visited Reykjavik, Iceland, to study the design of their geothermal district heating systems. This was in part the basis for the conceptual design and feasibility study (Lund, 1979) of a downtown commercial district. The main difference

  5. The Association Between Fall Frequency, Injury Risk, and Characteristics of Falls in Older Residents of Long-Term Care: Do Recurrent Fallers Fall More Safely?

    Science.gov (United States)

    van Schooten, Kimberley S; Yang, Yijian; Feldman, Fabio; Leung, Ming; McKay, Heather; Sims-Gould, Joanie; Robinovitch, Stephen N

    2018-05-09

    Although a fall is a necessary prerequisite to a fall-related injury, previous studies suggest that frequent fallers are at lower injury risk for a given fall. We tested the hypotheses that differences in protective responses or the circumstances of falls underlie differences in injury risk with fall frequency. We analyzed video footage of 897 falls experienced by 220 long-term care residents (mean age 82 ± 9 years) to identify the cause of imbalance, activity leading to falling, direction of fall initiation, balance recovery and fall protective responses, and occurrence of impact to the head or hip. We further obtained injury information from the facilities' fall registration. We used generalized estimating equation models to examine the association between quartiles of fall frequency, injury risk, and fall characteristics. Residents with the highest fall frequency group (Q4; ≥5.6 falls/year) were less likely to sustain an injury per fall. They were less likely to fall during walking and more likely to fall during stand-to-sit transfers. Residents in the lowest fall frequency group (Q1; falls/year) were more likely to fall during walking, and walking was associated with an increased risk for injury. When compared to less frequent fallers, more frequent fallers had a lower risk for injury per fall. This appeared to be explained by differences in the circumstances of falls, and not by protective responses. Injury prevention strategies in long-term care should target both frequent and infrequent fallers, as the latter are more mobile and apt to sustain injury.

  6. Precisely locating the Klamath Falls, Oregon, earthquakes

    Science.gov (United States)

    Qamar, A.; Meagher, K.L.

    1993-01-01

    The Klamath Falls earthquakes on September 20, 1993, were the largest earthquakes centered in Oregon in more than 50 yrs. Only the magnitude 5.75 Milton-Freewater earthquake in 1936, which was centered near the Oregon-Washington border and felt in an area of about 190,000 sq km, compares in size with the recent Klamath Falls earthquakes. Although the 1993 earthquakes surprised many local residents, geologists have long recognized that strong earthquakes may occur along potentially active faults that pass through the Klamath Falls area. These faults are geologically related to similar faults in Oregon, Idaho, and Nevada that occasionally spawn strong earthquakes. 

  7. Prevalence and cost of imaging in inpatient falls: the rising cost of falling

    Directory of Open Access Journals (Sweden)

    Fields J

    2015-06-01

    Full Text Available Jessica Fields,1 Tahani Alturkistani,2 Neal Kumar,3 Arjun Kanuri,3 Deeb N Salem,1 Samson Munn,2 Deborah Blazey-Martin1 1Department of Medicine, Tufts Medical Center, Boston, MA, USA; 2Department of Radiology, Tufts Medical Center, Boston, MA, USA; 3Tufts University School of Medicine, Boston, MA, USA Objective: To quantify the type, prevalence, and cost of imaging following inpatient falls, identify factors associated with post-fall imaging, and determine correlates of positive versus negative imaging. Design: Single-center retrospective cohort study of inpatient falls. Data were collected from the hospital's adverse event reporting system, DrQuality. Age, sex, date, time, and location of fall, clinical service, Morse Fall Scale/fall protocol, admitting diagnosis, and fall-related imaging studies were reviewed. Cost included professional and facilities fees for each study. Setting: Four hundred and fifteen bed urban academic hospital over 3 years (2008–2010. Patients: All adult inpatient falls during the study period were included. Falls experienced by patients aged <18 years, outpatient and emergency patients, visitors to the hospital, and staff were excluded. Measurements and main results: Five hundred and thirty inpatient falls occurred during the study period, average patient age 60.7 years (range 20–98. More than half of falls were men (55% and patients considered at risk of falls (56%. Falls were evenly distributed across morning (33%, evening (34%, and night (33% shifts. Of 530 falls, 178 (34% patients were imaged with 262 studies. Twenty percent of patients imaged had at least one positive imaging study attributed to the fall and 82% of studies were negative. Total cost of imaging was $160,897, 63% ($100,700 from head computed tomography (CT. Conclusion: Inpatient falls affect patients of both sexes, all ages, occur at any time of day and lead to expensive imaging, mainly from head CTs. Further study should be targeted toward

  8. Falls in institutions for older adults: characterization of fall occurrences and associated risk factors

    Directory of Open Access Journals (Sweden)

    Cristina Rosa Soares Lavareda Baixinho

    2015-12-01

    Full Text Available Falls are the main accident for older adults, with consequences on functionality. Older adults impose restrictions or have restrictions imposed on their activities for fear of new falls. This prospective longitudinal study was conducted with 104 institutionalized older adults during six months with the following goals: to determine the prevalence of falls, to characterize the falls according to place, time, resulting injuries, supervision of the older adult, action performed at the time of the fall, and to relate the occurrence of the fall to the risk of falling, medical diagnoses, number of medications in use, type of medication, degree of dependency, age, and gender. The prevalence of falls was 37.5%, and they happened mostly in the bedroom, while walking after getting up from the bed. Those under risk in the Morse Fall Scale (p=0.034 and on sedatives (p=0.007 face a higher prevalence of falls. This study enables the possibility of making suggestions for practice, training and investigation.

  9. Virtual obstacle crossing: Reliability and differences in stroke survivors who prospectively experienced falls or no falls.

    Science.gov (United States)

    Punt, Michiel; Bruijn, Sjoerd M; Wittink, Harriet; van de Port, Ingrid G; Wubbels, Gijs; van Dieën, Jaap H

    2017-10-01

    Stroke survivors often fall during walking. To reduce fall risk, gait testing and training with avoidance of virtual obstacles is gaining popularity. However, it is unknown whether and how virtual obstacle crossing is associated with fall risk. The present study assessed whether obstacle crossing characteristics are reliable and assessed differences in stroke survivors who prospectively experienced falls or no falls. We recruited twenty-nine community dwelling chronic stroke survivors. Participants crossed five virtual obstacles with increasing lengths. After a break, the test was repeated to assess test-retest reliability. For each obstacle length and trial, we determined; success rate, leading limb preference, pre and post obstacle distance, margins of stability, toe clearance, and crossing step length and speed. Subsequently, fall incidence was monitored using a fall calendar and monthly phone calls over a six-month period. Test-retest reliability was poor, but improved with increasing obstacle-length. Twelve participants reported at least one fall. No association of fall incidence with any of the obstacle crossing characteristics was found. Given the absence of height of the virtual obstacles, obstacle avoidance may have been relatively easy, allowing participants to cross obstacles in multiple ways, increasing variability of crossing characteristics and reducing the association with fall risk. These finding cast some doubt on current protocols for testing and training of obstacle avoidance in stroke rehabilitation. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Validation of the Saskatoon Falls Prevention Consortium's Falls Screening and Referral Algorithm

    Science.gov (United States)

    Lawson, Sara Nicole; Zaluski, Neal; Petrie, Amanda; Arnold, Cathy; Basran, Jenny

    2013-01-01

    ABSTRACT Purpose: To investigate the concurrent validity of the Saskatoon Falls Prevention Consortium's Falls Screening and Referral Algorithm (FSRA). Method: A total of 29 older adults (mean age 77.7 [SD 4.0] y) residing in an independent-living senior's complex who met inclusion criteria completed a demographic questionnaire and the components of the FSRA and Berg Balance Scale (BBS). The FSRA consists of the Elderly Fall Screening Test (EFST) and the Multi-factor Falls Questionnaire (MFQ); it is designed to categorize individuals into low, moderate, or high fall-risk categories to determine appropriate management pathways. A predictive model for probability of fall risk, based on previous research, was used to determine concurrent validity of the FSRI. Results: The FSRA placed 79% of participants into the low-risk category, whereas the predictive model found the probability of fall risk to range from 0.04 to 0.74, with a mean of 0.35 (SD 0.25). No statistically significant correlation was found between the FSRA and the predictive model for probability of fall risk (Spearman's ρ=0.35, p=0.06). Conclusion: The FSRA lacks concurrent validity relative to to a previously established model of fall risk and appears to over-categorize individuals into the low-risk group. Further research on the FSRA as an adequate tool to screen community-dwelling older adults for fall risk is recommended. PMID:24381379

  11. Fall Risk, Supports and Services, and Falls Following a Nursing Home Discharge.

    Science.gov (United States)

    Noureldin, Marwa; Hass, Zachary; Abrahamson, Kathleen; Arling, Greg

    2017-09-04

    Falls are a major source of morbidity and mortality among older adults; however, little is known regarding fall occurrence during a nursing home (NH) to community transition. This study sought to examine whether the presence of supports and services impacts the relationship between fall-related risk factors and fall occurrence post NH discharge. Participants in the Minnesota Return to Community Initiative who were assisted in achieving a community discharge (N = 1459) comprised the study sample. The main outcome was fall occurrence within 30 days of discharge. Factor analyses were used to estimate latent models from variables of interest. A structural equation model (SEM) was estimated to determine the relationship between the emerging latent variables and falls. Fifteen percent of participants fell within 30 days of NH discharge. Factor analysis of fall-related risk factors produced three latent variables: fall concerns/history; activities of daily living impairments; and use of high-risk medications. A supports/services latent variable also emerged that included caregiver support frequency, medication management assistance, durable medical equipment use, discharge location, and receipt of home health or skilled nursing services. In the SEM model, high-risk medications use and fall concerns/history had direct positive effects on falling. Receiving supports/services did not affect falling directly; however, it reduced the effect of high-risk medication use on falling (p risk of falling post NH discharge. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Electro-Deposition Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

  13. Atmospheric Deposition Modeling Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...

  14. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  15. Falls incidence underestimates the risk of fall-related injuries in older age groups : a comparison with the FARE (Falls risk by Exposure)

    NARCIS (Netherlands)

    Etman, Astrid; Wijlhuizen, Gert Jan; van Heuvelen, Marieke J. G.; Chorus, Astrid; Hopman-Rock, Marijke

    Background: up till now, the risk of falls has been expressed as falls incidence (i.e. the number of falls or fallers per 100 person-years). However, the risk of an accident or injury is the probability of having an accident or injury per unit of exposure. The FARE ( Falls risk by Exposure) is a

  16. Falls incidence underestimates the risk of fall-related injuries in older age groups: a comparison with the FARE (Falls risk by Exposure)

    NARCIS (Netherlands)

    Etman, A.; Wijlhuizen, G.J.; van Heuvelen, M.J.G.; Chorus, A.M.J.; Hopman-Rock, M.

    2012-01-01

    Background: up till now, the risk of falls has been expressed as falls incidence (i.e. the number of falls or fallers per 100 person-years). However, the risk of an accident or injury is the probability of having an accident or injury per unit of exposure. The FARE (Falls risk by Exposure) is a

  17. Falls incidence underestimates the risk of fall-related injuries in older age groups: A comparison with the FARE (Falls risk by exposure)

    NARCIS (Netherlands)

    Etman, A.; Wijlhuizen, G.J.; Heuvelen, M.J.G. van; Chorus, A.; Hopman-Rock, M.

    2012-01-01

    Background: up till now, the risk of falls has been expressed as falls incidence (i.e. the number of falls or fallers per 100 person-years). However, the risk of an accident or injury is the probability of having an accident or injury per unit of exposure. The FARE (Falls risk by Exposure) is a

  18. Forensic Physics 101: Falls from a height

    Science.gov (United States)

    Cross, Rod

    2008-09-01

    The physics of falling from a height, a topic that could be included in a course on forensic physics or in an undergraduate class as an example of Newton's laws, is applied to a common forensic problem.

  19. Falls Among Older Adults: An Overview

    Science.gov (United States)

    ... out some of our online STEADI resources for older adults. These resources include: Stay Independent brochure What You Can Do to Prevent Falls brochure Check for Safety brochure Postural Hypotension brochure Chair Rise Exercise Related Pages Costs ...

  20. FEAR OF FALLING AMONG COMMUNITY DWELLING OLDER ADULTS

    Directory of Open Access Journals (Sweden)

    Michaela Dingová

    2017-03-01

    Full Text Available Aim: The aim of the study was to describe experience with falls, fear of falling, perceptions of the consequences of falls and how the fear of falling affects daily life in community-dwelling older adults. Design: The study used a qualitative design to describe the lived experiences of community-dwelling older adults with the fear of falling. Methods: Semi-structured interviews were conducted individually with six participants who reported the fear of falling. Results: Five main areas emerged from data analysis: development of the fear of falling, feared consequences of falling, activities curtailment, fall prevention behavior and meaning of social support in daily life. The fear of falling was described as a negative experience, directly linked to fall consequences such as physical injury, incapacitation, loss of autonomy, fear of dependence and experience of humiliating conditions. To maintain a certain level of independence in daily life, the participants chose to avoid falls by activity curtailment, organizing their lives more carefully and getting support from others. Conclusion: All participants identified that they had discovered their fear of falling after experiencing falls. The fear of falling was associated with feared consequences of a potential fall and had an impact on their daily life. The participant also mentioned other contributors to their fear of falling, including ill health and aging. Keywords: Fear of falling, older adults, perceived consequences of falls, daily life.

  1. Fall risk in an active elderly population

    DEFF Research Database (Denmark)

    Læssøe, Uffe; Hoeck, Hans C.; Simonsen, Ole

    2007-01-01

    risk can be assessed by testing balance performance. In this study a test battery of physiological parameters related to balance and falls was designed to address fall risk in a community dwelling elderly population. RESULTS: Ninety-four elderly males and females between 70 and 80 years of age were...... assessment in which the physiological performance is evaluated in relation to the activity profile of the individual. Udgivelsesdato: 2007-null...

  2. On the Motion of Falling Leaves

    OpenAIRE

    Razavi, Pedram

    2010-01-01

    This paper investigates the motion of falling leaves through modeling using papers and the corresponding data collected from more than four thousands experiments. Two series of experiments were designed in order to study the relationship between different parameters which can affect different paths of motion in leaves. In the first series of experiments, the shapes of the potential paths that falling papers can take were investigated as a whole. A new classification scheme was derived from th...

  3. Quantifying Temperature Effects on Fall Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Yetta [ORNL

    2011-11-01

    The motivation for this study was to recommend relationships for use in a model of San Joaquin fall Chinook salmon. This report reviews literature pertaining to relationships between water temperature and fall Chinook salmon. The report is organized into three sections that deal with temperature effects on development and timing of freshwater life stages, temperature effects on incubation survival for eggs and alevin, and temperature effects on juvenile survival. Recommendations are made for modeling temperature influences for all three life stages.

  4. Tephrostratigraphy of Changbaishan volcano, northeast China, since the mid-Holocene

    Science.gov (United States)

    Sun, Chunqing; Liu, Jiaqi; You, Haitao; Nemeth, Karoly

    2017-12-01

    A detailed tephrostratigraphy of an active volcano is essential for evaluating its eruptive history, forecasting future eruptions and correlation with distal tephra records. Changbaishan volcano is known for its Millennium eruption (ME, AD 940s; VEI 7) and the ME tephra has been detected in Greenland ice cores ∼9000 km from the vent. However, the pre-Millennium (pre-ME) and post-Millennium (post-ME) eruptions are still poorly characterized. In this study, we present a detailed late Holocene eruptive sequence of Changbaishan volcano based on single glass shard compositions from tephra samples collected from around the caldera rim and flanks. Tephra ages are constrained by optically stimulated luminescence (OSL) and AMS 14C dates. Tephra from the mid-Holocene pre-ME eruption can be divided into two pyroclastic fall subunits, and it cannot be correlated with any known Changbaishan-sourced tephra recorded in the Japan Sea based on major element composition of glass shards, such as the B-J (Baegdusan-Japan Basin) and B-V (Baegdusan-Vladivostok-oki) tephras. ME pyroclastic fall deposits from the caldera rims and volcanic flanks can be correlated to the juvenile pumice lapilli or blocks within the pyroclastic density current (PDC) deposits deposited in the valleys around the volcano based on glass shard compositions. Our results indicate that the glass shard compositions of proximal ME tephra are more varied than previously thought and can be correlated with distal ME tephra. In addition, widely-dispersed mafic scoria was ejected by the ME Plinian column and deposited on the western and southern summits and the eastern flank of the volcano. Data for glass from post-ME eruptions, such as the historically-documented AD 1403, AD 1668 and AD 1702 eruptions, are reported here for the first time. Except for the ME, other Holocene eruptions, including pre-ME and post-ME eruptions, had the potential to form widely-distributed tephra layers around northeast Asia, and our dataset

  5. Elderly outpatient profile and predictors of falls.

    Science.gov (United States)

    Gomes, Grace Angélica de Oliveira; Cintra, Fernanda Aparecida; Batista, Fernanda Sotelo; Neri, Anita Liberalesso; Guariento, Maria Elena; Sousa, Maria da Luz Rosario de; D'Elboux, Maria José

    2013-01-01

    CONTEXT AND OBJECTIVES Falls are a serious public health problem and are one of the biggest reasons for hospitalization, morbidity and mortality among elderly people. Moreover, few studies on predictors of falls have been conducted in low and middle income countries. The aim here was to identify elderly outpatient profiles according to sociodemographic, clinical, physical and functional variables and correlate them with occurrences of falls among these subjects. DESIGN AND SETTING Cross-sectional descriptive study forming part of the project "Quality of Life of Frail Elderly People", carried out in Campinas, Brazil. METHODS The subjects were 145 elderly individuals (76.3 ± 7.8 years old), of whom 65% were women, who were living in the city of Campinas or nearby and were attended at the geriatric outpatient clinic of a University Hospital. Sociodemographic, clinical, physical and functional data, as well as fall occurrence data, were gathered. Cluster analyses and comparisons between groups were carried out. RESULTS Cluster analysis identified two distinct groups related to the study variables, and the determinants for this distinction were: gender, marital status, physical performance, handgrip strength and functional independence. These groups were compared according to occurrences of falls over the last year, and significant differences between them were found. CONCLUSIONS The results showed that greater occurrences of falls were associated with a profile of elderly people comprising female gender, single status, lower muscle strength and physical performance regarding balance and gait, and lower independence in motor tasks for activities of daily living.

  6. Falls and depression in older people.

    Science.gov (United States)

    Turcu, Alin; Toubin, Sandrine; Mourey, France; D'Athis, Philippe; Manckoundia, Patrick; Pfitzenmeyer, Pierre

    2004-01-01

    Depression is one of the most common risk factors for falls, but links between falls and depression are still unclear. Few studies have examined the relationship between depression and gait alteration, which may increase the risk of fall. This study aims to assess a possible relationship between depression, postural and gait abnormalities, and falls. We conducted a 1-year prospective study on patients >/=70 years who were admitted to a geriatric unit for 'spontaneous' unexplained falls. Patients were tested for depression using the 30-item Geriatric Depression Scale (GDS). Their motor performances were assessed using the Mini Motor Test (MMT), which is an easy direct-observation test, validated in France, for assessment of frail old people who present with severe postural and gait impairment. This scale is composed of 4 categories of items: (1) abilities in bed; (2) quality of the sitting position; (3) abilities in the standing position, and (4) quality of gait. Sixty-nine patients were included. Depression was found in 46 patients (66.7%). The MMT score was higher in the non-depressed fallers (NDF) group (GDS 10; p predispose to falls. In clinical practice, more attention should be given to old fallers concerning diagnosis and treatment of associated depression. Copyright 2004 S. Karger AG, Basel

  7. Seasonal variability in 7Be depositional fluxes at Granada, Spain

    International Nuclear Information System (INIS)

    Gonzalez-Gomez, C.; Azahra, M.; Lopez-Penalver, J.J.; Camacho-Garcia, A.; Bardouni, T.El.; Boukhal, H.

    2006-01-01

    Measurement of 7 Be depositional fluxes at Granada, Spain (37 o 10'50''N-3 o 35'44''W, altitude 670 m) in the period 1995 through 1998 indicates substantial variations between the four seasons and also between corresponding seasons in different years, ranging from 23.6 to 242 Bq m -2 per season. A strongly positive correlation with precipitation is shown, which explains about 70% of the variations in the 7 Be depositional fluxes over the 16 seasons studied. The depositional 7 Be flux is on the average highest in the fall and lowest in the summer. The study shows that precipitation primarily controls the 7 Be depositional flux and plays a dominant role in the removal of 7 Be from the troposphere. The average annual 7 Be depositional flux at Granada amounts to 469+145 Bq m -2

  8. The interplay between gait, falls and cognition: can cognitive therapy reduce fall risk?

    Science.gov (United States)

    Segev-Jacubovski, Orit; Herman, Talia; Yogev-Seligmann, Galit; Mirelman, Anat; Giladi, Nir; Hausdorff, Jeffrey M

    2011-01-01

    In this article, we briefly summarize the incidence and significant consequences of falls among older adults, the insufficient effectiveness of commonly used multifactorial interventions and the evidence linking falls and cognitive function. Recent pharmacologic and nonpharmacologic studies that evaluated the effects of cognitive therapy on fall risk are reviewed. The results of this article illustrate the potential utility of multiple, diverse forms of cognitive therapy for reducing fall risk. The article also indicates that large-scale, randomized controlled trials are warranted and that additional research is needed to better understand the pathophysiologic mechanisms underlying the interplay between human mobility, fall risk and cognitive function. Nonetheless, we suggest that multimodality interventions that combine motor and cognitive therapy should, eventually, be incorporated into clinical practice to enable older adults and patients to move safer and with a reduced fall risk. PMID:21721921

  9. An outpatient multifactorial falls prevention intervention does not reduce falls in high-risk elderly Danes

    DEFF Research Database (Denmark)

    Vind, Ane B; Andersen, Hanne E; Pedersen, Kirsten D

    2009-01-01

    , mean age 74, 73.7%women, who had visited the emergency department or had been hospitalized due to a fall. INTERVENTION: Identification of general medical, cardiovascular, and physical risk factors for falls and individual intervention in the intervention group. Participants in the control group....... Followup exceeded 90.0%. A total of 422 falls were registered in the intervention group, 398 in the control group. Intention-to-treat analysis revealed no effect of the intervention on fall rates (relative risk=1.06, 95%confidence interval (CI)=0.75 -1.51), proportion with falls (odds ratio (OR)=1.20, 95......OBJECTIVES: To evaluate the effect of multifactorial fall prevention in community-dwelling people aged 65 and older in Denmark. DESIGN: Randomized, controlled clinical trial. SETTING: Geriatric outpatient clinic at Glostrup University Hospital. PARTICIPANTS: Three hundred ninety-two elderly people...

  10. Fall predictors in older cancer patients: a multicenter prospective study

    OpenAIRE

    Vande Walle, Nathalie; Kenis, Cindy; Heeren, Pieter; Van Puyvelde, Katrien; Decoster, Lore; Beyer, Ingo; Conings, Godelieve; Flamaing, Johan; Lobelle, Jean-Pierre; Wildiers, Hans; Milisen, Koen

    2014-01-01

    Background In the older population falls are a common problem and a major cause of morbidity, mortality and functional decline. The etiology is often multifactorial making the identification of fall predictors essential for preventive measures. Despite this knowledge, data on falls within the older cancer population are limited. The objective of this study was to evaluate the occurrence of falls within 2 to 3?months after cancer treatment decision and to identify predictors of falls (?1 fall)...

  11. FEAR OF FALLING AMONG COMMUNITY DWELLING OLDER ADULTS

    OpenAIRE

    Michaela Dingová; Eva Králová

    2017-01-01

    Aim: The aim of the study was to describe experience with falls, fear of falling, perceptions of the consequences of falls and how the fear of falling affects daily life in community-dwelling older adults. Design: The study used a qualitative design to describe the lived experiences of community-dwelling older adults with the fear of falling. Methods: Semi-structured interviews were conducted individually with six participants who reported the fear of falling. Results: Five main areas emerged...

  12. The recent pumice eruptions of Mt. Pelée volcano, Martinique. Part I: Depositional sequences, description of pumiceous deposits

    Science.gov (United States)

    Traineau, Hervé; Westercamp, Denis; Bardintzeff, Jacques-Marie; Miskovsky, Jean-Claude

    1989-08-01

    Mount Pelée is one of the most active volcanoes of the Lesser Antilles arc, with more than twenty eruptions over the last 5000 years. Both nuée ardente-type eruptions, which are well known, and pumice eruptions, although little known, are very common in the stratigraphic record. The four younger pumice eruptions, P4 (2440 y.B.P.), P3 (2010 y.B.P.), P2 (1670 y.B.P.) and P1 (650 y.B.P.) can be used to reconstruct the eruption sequences. The various pumiceous deposits can be described as fine lithic ash layer, Plinian fall deposits, pumice and ash flow deposits with associated ash cloud fall deposits, and pumice surge deposits. Three kinds of depositional sequences have been defined. The distinctions between them are based on the occurrence of an initial Plinian phase and the generation of intraflow pyroclastic surges. The pumice eruptions of Mt. Pelée are small in intensity and magnitude, as expressed by the dispersal of their products and by the total mass of erupted material which is estimated to be less than 1 km 3 in each case. The pumice fall deposits have dispersal characteristics of small Plinian eruptions, close to the sub-Plinian type. Nevertheless, the probability of an occurrence of a new pumice eruption at Mt. Pelée is high, and the widespread distribution of pumice deposits around the volcano suggests that such an eruption is a major volcanic risk during the present stage of activity.

  13. Fall speed measurement and high-resolution multi-angle photography of hydrometeors in free fall

    OpenAIRE

    T. J. Garrett; C. Fallgatter; K. Shkurko; D. Howlett

    2012-01-01

    We describe here a new instrument for imaging hydrometeors in free fall. The Multi-Angle Snowflake Camera (MASC) captures high-resolution photographs of hydrometeors from three angles while simultaneously measuring their fall speed. Based on the stereoscopic photographs captured over the two months of continuous measurements obtained at a high altitude location within the Wasatch Front in Utah, we derive statistics for fall speed, hydrometeor size, shape, orientation and asp...

  14. Falling and fall risk factors in adults with haemophilia: an exploratory study.

    Science.gov (United States)

    Sammels, M; Vandesande, J; Vlaeyen, E; Peerlinck, K; Milisen, K

    2014-11-01

    Falls are a particular risk in persons with haemophilia (PWH) because of damaged joints, high risk of bleeding, possible impact on the musculoskeletal system and functioning and costs associated with treatment for these fall-related injuries. In addition, fall risk increases with age and PWH are increasingly entering the over 65 age group. The aim of this study was to determine the occurrence of falls during the past year and to explore which fall risk factors are present in community-dwelling PWH. Dutch speaking community-dwelling adults were included from the age of 40 years with severe or moderate haemophilia A or B, independent in their mobility and registered at the University Hospitals Leuven. They were asked to come to the haemophilia centre; otherwise a telephone survey was conducted. Demographic and social variables, medical variables, fall evaluation and clinical variables were queried. From the 89 PWH, 74 (83.1%) participated in the study. Twenty-four (32.4%) fell in the past year, and 10 of them (41.7%) more than once with an average of four falls. Living conditions, physical activity, avoidance of winter sports due to fear of falling, orthopaedic status, urinary incontinence and mobility impairments are potential fall risk factors in adult PWH. This exploratory study indicates that PWH are attentive to falling since they are at higher risk for falls and because of the serious consequences it might have. Screening and fall prevention should be stimulated in the daily practice of haemophilia care. © 2014 John Wiley & Sons Ltd.

  15. Relationship Between Perceived Risk of Falling and Adoption of Precautions to Reduce Fall Risk.

    Science.gov (United States)

    Blalock, Susan J; Gildner, Paula L; Jones, Jennifer L; Bowling, James M; Casteel, Carri H

    2016-06-01

    To better understand the relationship between perceived risk of falling and awareness and adoption of four specific precautions that older adults have taken to reduce this risk. Cross-sectional. Data were collected in in-person interviews conducted in the homes of study participants. Interviews conducted between March 2011 and September 2013 and lasted an average of 60-90 minutes. A stratified sampling strategy designed to enroll an equal number of homebound and nonhomebound participants was used. All participants (N = 164) were recruited from central North Carolina. Participants were asked about 1-year fall history, perceived risk of falling, restriction of activities because of fear of falling, awareness of four recommended fall prevention behaviors (exercise, annual medication review, bathroom grab bars, safe footwear), and current practice of these behaviors. In bivariate analyses, individuals who were aware of two behaviors recommended to reduce the risk of falling (exercise, use of safe footwear) and had adopted these behaviors perceived their risk of falling as lower than individuals who were aware of the recommended behaviors but had not adopted them. Moreover, in multivariate analyses, individuals who did not know that exercise is recommended to reduce the risk of falling perceived their risk of falling as lower than those who were aware of this recommendation and had adopted it. Individuals were least likely to be aware that medication reviews and exercise are recommended to reduce fall risk. Awareness of behaviors recommended to reduce fall risk appears necessary for adoption of these behaviors to reduce perceived risk. Fall-prevention campaigns should emphasize behaviors where awareness is low. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  16. The Correlation Between Rates of Falling, Balance, Quality of Life and Fear of Falling in Patients With Chronic Stroke

    Directory of Open Access Journals (Sweden)

    Hamid Azadeh

    2018-04-01

    Conclusion The findings of the present study demonstrated the correlation between balance, physical dimensions of quality of life and fear of falling in patients with stroke; however, the rate of falling has no association with fear of falling.

  17. The Neighborhood Environment: Perceived Fall Risk, Resources, and Strategies for Fall Prevention.

    Science.gov (United States)

    Chippendale, Tracy; Boltz, Marie

    2015-08-01

    To explore the experience of older adults in their neighborhood in relation to perceived fall risk, fear of falling (FOF), and resources/strategies for fall prevention. Fourteen older adults, 65 years of age and older from 3 urban senior centers, participated in this qualitative study. The semistructured interview guidelines and background questionnaire were developed by the researchers based on the literature and an existing measure of walkability. Both tools were refined based on pilot interviews with seniors. Collaizzi's phenomenological method was used for data analysis. Five themes emerged from the data: (a) The built environment contributes to perceived fall risk and FOF, (b) personal strategies used to adapt to perceived neighborhood fall risks-behavioral approaches, (c) resources for physical activity and safety, (d) barriers to physical activity and exercise, and (e) neighborhood features as a motivator. Urban-dwelling seniors perceive that neighborhood features contribute to or mitigate fall risk and FOF. Behavioral strategies are used by seniors to prevent outdoor falls. The findings can help clinicians develop targeted fall prevention interventions for well elders and help urban planners to design and retrofit urban environments to reduce fall risk. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Fall risk assessment: retrospective analysis of Morse Fall Scale scores in Portuguese hospitalized adult patients.

    Science.gov (United States)

    Sardo, Pedro Miguel Garcez; Simões, Cláudia Sofia Oliveira; Alvarelhão, José Joaquim Marques; Simões, João Filipe Fernandes Lindo; Melo, Elsa Maria de Oliveira Pinheiro de

    2016-08-01

    The Morse Fall Scale is used in several care settings for fall risk assessment and supports the implementation of preventive nursing interventions. Our work aims to analyze the Morse Fall Scale scores of Portuguese hospitalized adult patients in association with their characteristics, diagnoses and length of stay. Retrospective cohort analysis of Morse Fall Scale scores of 8356 patients hospitalized during 2012. Data were associated to age, gender, type of admission, specialty units, length of stay, patient discharge, and ICD-9 diagnosis. Elderly patients, female, with emergency service admission, at medical units and/or with longer length of stays were more frequently included in the risk group for falls. ICD-9 diagnosis may also be an important risk factor. More than a half of hospitalized patients had "medium" to "high" risk of falling during the length of stay, which determines the implementation and maintenance of protocoled preventive nursing interventions throughout hospitalization. There are several fall risk factors not assessed by Morse Fall Scale. There were no statistical differences in Morse Fall Scale score between the first and the last assessment. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Classification of uraniferous vein deposits (1960)

    International Nuclear Information System (INIS)

    Geffroy, J.; Sarcia, J.A.

    1960-01-01

    On the basis of a study of French uraniferous seams and of information found in the literature from all parts of the world, especially since the first Geneva Conference (1955), the authors class these deposits according to two broad categories: - the first type, bound up with the differentiation of an acid rock, fall naturally into the conventional hydrothermal category; - the others come right outside it and seem to be connected to some age modifications, originally of tectonic origin, of the uranium dispersed amongst the rocks on a regional scale. (author) [fr

  20. Aerosol Deposition and Solar Panel Performance

    Science.gov (United States)

    Arnott, W. P.; Rollings, A.; Taylor, S. J.; Parks, J.; Barnard, J.; Holmes, H.

    2015-12-01

    Passive and active solar collector farms are often located in relatively dry desert regions where cloudiness impacts are minimized. These farms may be susceptible to reduced performance due to routine or episodic aerosol deposition on collector surfaces. Intense episodes of wind blown dust deposition may negatively impact farm performance, and trigger need to clean collector surfaces. Aerosol deposition rate depends on size, morphology, and local meteorological conditions. We have developed a system for solar panel performance testing under real world conditions. Two identical 0.74 square meter solar panels are deployed, with one kept clean while the other receives various doses of aerosol deposition or other treatments. A variable load is used with automation to record solar panel maximum output power every 10 minutes. A collocated sonic anemometer measures wind at 10 Hz, allowing for both steady and turbulent characterization to establish a link between wind patterns and particle distribution on the cells. Multispectral photoacoustic instruments measure aerosol light scattering and absorption. An MFRSR quantifies incoming solar radiation. Solar panel albedo is measured along with the transmission spectra of particles collected on the panel surface. Key questions are: At what concentration does aerosol deposition become a problem for solar panel performance? What are the meteorological conditions that most strongly favor aerosol deposition, and are these predictable from current models? Is it feasible to use the outflow from an unmanned aerial vehicle hovering over solar panels to adequately clean their surface? Does aerosol deposition from episodes of nearby forest fires impact performance? The outlook of this research is to build a model that describes environmental effects on solar panel performance. Measurements from summer and fall 2015 will be presented along with insights gleaned from them.

  1. Assessment of risk for falls in elderly

    Directory of Open Access Journals (Sweden)

    Stanetić Kosana

    2014-01-01

    Full Text Available Introduction: Elderly persons have higher risk for falls, compared to younger population. Although no single risk factor causes all falls, a great deal of risk factors to which an individual is exposed, i.e. osteoporosis, lack of physical activity, impaired vision, usage of drugs, living settings etc, can be treated. Objective: To investigate the risk for falls in elderly patients treated in Family medicine teaching center (ECPM, Primary Health Care Center Banja Luka. Method: This prospective study was conducted in June 2012. The study included 150 patients aged 65 years and older. Patients were chosen randomly. In study were included patients who have visited their family doctors on every of Mondays in June 2012. The Tinetti Gait and Balance Instrument was used to asses the risk for falls. Patients were examined to asses gait and balance according to Tinetti questionnaire, and supplementary questionnaire was created to record data about age, sex, chronic diseases and drugs that patients take. Results: The study included 91 (60.7% female and 59 (39.3% male patients. The average age of patients was 74.71 years. 77 (51.3% were aged 65 to 75 years and 73 (48.7% were more than 75 years old. Results of Tinetti Gait and Balance Instrument showed that the risk for falls was high in 55 (36.7%, moderate in 31 (20.7% and low in 64 (42.7% patients. Conclusion: Approximately, one third of investigated patients had high risk for falls, what indicates that family doctors should be more involved in fall prevention in elderly and in constant educating of older adults and their families.

  2. Risk of falling in a stroke unit after acute stroke: The Fall Study of Gothenburg (FallsGOT).

    Science.gov (United States)

    Persson, Carina U; Kjellberg, Sigvar; Lernfelt, Bodil; Westerlind, Ellen; Cruce, Malin; Hansson, Per-Olof

    2018-03-01

    This study aimed to investigate incidence of falls and different baseline variables and their association with falling during hospitalization in a stroke unit among patients with acute stroke. Prospective observational study. A stroke unit at a university hospital. A consecutive sample of stroke patients, out of which 504 were included, while 101 declined participation. The patients were assessed a mean of 1.7 days after admission and 3.8 days after stroke onset. The primary end-point was any fall, from admission to the stroke unit to discharge. Factors associated with falling were analysed using univariable and multivariable Cox hazard regression analyses. Independent variables were related to function, activity and participation, as well as personal and environmental factors. In total, 65 patients (13%) fell at least once. Factors statistically significantly associated with falling in the multivariable analysis were male sex (hazard ratio (HR): 1.88, 95% confidence interval (CI): 1.13-3.14, P = 0.015), use of a walking aid (HR: 2.11, 95% CI: 1.24-3.60, P = 0.006) and postural control as assessed with the modified version of the Postural Assessment Scale for Stroke Patients (SwePASS). No association was found with age, cognition or stroke severity, the HR for low SwePASS scores (⩽24) was 9.33 (95% CI: 2.19-39.78, P = 0.003) and for medium SwePASS scores (25-30) was 6.34 (95% CI: 1.46-27.51, P = 0.014), compared with high SwePASS scores (⩾31). Postural control, male sex and use of a walking aid are associated with falling during hospitalization after acute stroke.

  3. Dynamic loading of the structural wall in a lithium fall fusion reactor

    International Nuclear Information System (INIS)

    Glenn, L.A.

    1979-01-01

    In one version of an inertial confinement fusion (ICF) power reactor, the laser-imploded pellet is surrounded by a thick, annular 'waterfall' of liquid lithium. The fall has three functions: to breed tritium for pellet resupply, to act as an energy sink and heat exchange mdeium with an external power loop, and to protect the first wall of the reactor from excessive neutronic and hydrodynamic loading. Our primary concern here is with this last function. We formulated a simple model of a lithium-fall ICF reactor and calculated the fall disassembly and the subsequent fluid-wall interaction resulting from the energy deposition by the imploded pellet. Two potential mechanisms for wall damage were identified: surface erosion and hoop failure. For single fall designs, the erosion problem appears to be serious. Concentric annuli (multiple fall) or packed jet configurations may be feasible but experiments are needed to clarify the physical model, especially with reg (orig.)ard to /orig.the characteristics of the cavitated liquid lithium and of the two-phase liquid-vapor region.

  4. Electronic Out-fall Inspection Application - 12007

    Energy Technology Data Exchange (ETDEWEB)

    Weymouth, A Kent III; Pham, Minh; Messick, Chuck [Savannah River Nuclear Solutions, Aiken, South Carolina 29808 (United States)

    2012-07-01

    In early 2009 an exciting opportunity was presented to the Geographic Information Systems (GIS) team at the Savannah River Site (SRS). The SRS maintenance group was directed to maintain all Out-falls on Site, increasing their workload from 75 to 183 out-falls with no additional resources. The existing out-fall inspection system consisted of inspections performed manually and documented via paper trail. The inspections were closed out upon completion of activities and placed in file cabinets with no central location for tracking/trending maintenance activities. A platform for meeting new improvements required for documentation by the Department of Health and Environmental Control (DHEC) out-fall permits was needed to replace this current system that had been in place since the 1980's. This was accomplished by building a geographically aware electronic application that improved reliability of site out-fall maintenance and ensured consistent standards were maintained for environmental excellence and worker efficiency. Inspections are now performed via tablet and uploaded to a central point. Work orders are completed and closed either in the field using tablets (mobile application) or in their offices (via web portal) using PCs. And finally completed work orders are now stored in a central database allowing trending of maintenance activities. (authors)

  5. Stick balancing, falls and Dragon-Kings

    Science.gov (United States)

    Cabrera, J. L.; Milton, J. G.

    2012-05-01

    The extent to which the occurrence of falls, the dominant feature of human attempts to balance a stick at their fingertip, can be predicted is examined in the context of the "Dragon-King" hypothesis. For skilled stick balancers, fluctuations in the controlled variable, namely the vertical displacement angle θ, exhibit power law behaviors. When stick balancing is made less stable by either decreasing the length of the stick or by requiring the subject to balance the stick on the surface of a table tennis racket, systematic departures from the power law behaviors are observed in the range of large θ. This observation raises the possibility that the presence of departures from the power law in the large length scale region, possibly Dragon-Kings, may identify situations in which the occurrence of a fall is more imminent. However, whether or not Dragon-Kings are observed, there is a Weibull-type survival function for stick falling. The possibility that increased risk of falling can, at least to some extent, be predicted from fluctuations in the controlled variable before the event occurs has important implications for the development of preventative strategies for the management of phenomena ranging from earthquakes to epileptic seizures to falls in the elderly.

  6. Detection and Prevention of Seniors Falls

    Directory of Open Access Journals (Sweden)

    Lubomír MACKŮ

    2016-11-01

    Full Text Available The paper deals with the issue of seniors’ security and safety, namely the security problems related to falls of independently living elderly citizens. The number of elderly people is growing very fast worldwide and very often they live unattended in their house or flat. In case of accidently falling down, they are often unable help themselves and stay on the floor for hours or even longer. This may lead even to the death if no help comes. Various possibilities of their fall detection are studied. We analyze the historical development, current capabilities and efficiency of different approaches and methods. We address the willingness and ability of seniors to actively use technology, detection limits, privacy, personal data security and other important factors. In addition, we discuss the challenges, current shortcomings, issues and trends in fall detection or operation reliability in real-life conditions. The main future goal would be to maintain the personal privacy and security of irrelevant information in modern fall detection systems.

  7. Elderly outpatient profile and predictors of falls

    Directory of Open Access Journals (Sweden)

    Grace Angélica de Oliveira Gomes

    Full Text Available CONTEXT AND OBJECTIVESFalls are a serious public health problem and are one of the biggest reasons for hospitalization, morbidity and mortality among elderly people. Moreover, few studies on predictors of falls have been conducted in low and middle income countries. The aim here was to identify elderly outpatient profiles according to sociodemographic, clinical, physical and functional variables and correlate them with occurrences of falls among these subjects.DESIGN AND SETTINGCross-sectional descriptive study forming part of the project “Quality of Life of Frail Elderly People”, carried out in Campinas, Brazil.METHODSThe subjects were 145 elderly individuals (76.3 ± 7.8 years old, of whom 65% were women, who were living in the city of Campinas or nearby and were attended at the geriatric outpatient clinic of a University Hospital. Sociodemographic, clinical, physical and functional data, as well as fall occurrence data, were gathered. Cluster analyses and comparisons between groups were carried out.RESULTSCluster analysis identified two distinct groups related to the study variables, and the determinants for this distinction were: gender, marital status, physical performance, handgrip strength and functional independence. These groups were compared according to occurrences of falls over the last year, and significant differences between them were found.CONCLUSIONSThe results showed that greater occurrences of falls were associated with a profile of elderly people comprising female gender, single status, lower muscle strength and physical performance regarding balance and gait, and lower independence in motor tasks for activities of daily living.

  8. Accidents due to falls from roof slabs.

    Science.gov (United States)

    Rudelli, Bruno Alves; Silva, Marcelo Valerio Alabarce da; Akkari, Miguel; Santili, Claudio

    2013-01-01

    CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%). Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%), and flying a kite was the most prevalent game (37.9%). In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  9. Accidents due to falls from roof slabs

    Directory of Open Access Journals (Sweden)

    Bruno Alves Rudelli

    Full Text Available CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%. Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%, and flying a kite was the most prevalent game (37.9%. In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  10. Timescales of mixing and storage for Keanakāko`i Tephra magmas (1500-1820 C.E.), Kīlauea Volcano, Hawai`i

    Science.gov (United States)

    Lynn, Kendra J.; Garcia, Michael O.; Shea, Thomas; Costa, Fidel; Swanson, Donald A.

    2017-09-01

    The last 2500 years of activity at Kīlauea Volcano (Hawai`i) have been characterized by centuries-long periods dominated by either effusive or explosive eruptions. The most recent period of explosive activity produced the Keanakāko`i Tephra (KT; ca. 1500-1820 C.E.) and occurred after the collapse of the summit caldera (1470-1510 C.E.). Previous studies suggest that KT magmas may have ascended rapidly to the surface, bypassing storage in crustal reservoirs. The storage conditions and rapid ascent hypothesis are tested here using chemical zoning in olivine crystals and thermodynamic modeling. Forsterite contents (Fo; [Mg/(Mg + Fe) × 100]) of olivine core and rim populations are used to identify melt components in Kīlauea's prehistoric (i.e., pre-1823) plumbing system. Primitive (≥Fo88) cores occur throughout the 300+ years of the KT period; they originated from mantle-derived magmas that were first mixed and stored in a deep crustal reservoir. Bimodal olivine populations (≥Fo88 and Fo83-84) record repeated mixing of primitive magmas and more differentiated reservoir components shallower in the system, producing a hybrid composition (Fo85-87). Phase equilibria modeling using MELTS shows that liquidus olivine is not stable at depths >17 km. Thus, calculated timescales likely record mixing and storage within the crust. Modeling of Fe-Mg and Ni zoning patterns (normal, reverse, complex) reveal that KT magmas were mixed and stored for a few weeks to several years before eruption, illustrating a more complex storage history than direct and rapid ascent from the mantle as previously inferred for KT magmas. Complexly zoned crystals also have smoothed compositional reversals in the outer 5-20 µm rims that are out of Fe-Mg equilibrium with surrounding glasses. Diffusion models suggest that these rims formed within a few hours to a few days, indicating that at least one additional, late-stage mixing event may have occurred shortly prior to eruption. Our study

  11. Older people's perception of and coping with falling, and their motivation for fall-prevention programmes

    DEFF Research Database (Denmark)

    Høst, Dorte; Hendriksen, Carsten; Borup, Ina

    2011-01-01

    This study aims to investigate older people's perceptions of and coping with falls, and what motivates them to join such programmes.......This study aims to investigate older people's perceptions of and coping with falls, and what motivates them to join such programmes....

  12. Martial arts fall techniques decrease the impact forces at the hip during sideways falling.

    NARCIS (Netherlands)

    Groen, B.E.; Weerdesteijn, V.G.M.; Duysens, J.E.J.

    2007-01-01

    Falls to the side and those with impact on the hip are risky for hip fractures in the elderly. A previous study has indicated that martial arts (MA) fall techniques can reduce hip impact force, but the underlying mechanism is unknown. Furthermore, the high impact forces at the hand used to break the

  13. Spinal sagittal contour affecting falls: cut-off value of the lumbar spine for falls.

    Science.gov (United States)

    Ishikawa, Yoshinori; Miyakoshi, Naohisa; Kasukawa, Yuji; Hongo, Michio; Shimada, Yoichi

    2013-06-01

    Spinal deformities reportedly affect postural instability or falls. To prevent falls in clinical settings, the determination of a cut-off angle of spinal sagittal contour associated with increase risk for falls would be useful for screening for high-risk fallers. The purpose of this study was to calculate the spinal sagittal contour angle associated with increased risk for falls during medical checkups in community dwelling elders. The subjects comprised 213 patients (57 men, 156 women) with a mean age of 70.1 years (range, 55-85 years). The upright and flexion/extension thoracic kyphosis and lumbar lordosis angles, and the spinal inclination were evaluated with SpinalMouse(®). Postural instability was evaluated by stabilometry, using the total track length (LNG), enveloped areas (ENV), and track lengths in the lateral and anteroposterior directions (X LNG and Y LNG, respectively). The back extensor strength (BES) was measured using a strain-gauge dynamometer. The relationships among the parameters were analyzed statistically. Age, lumbar lordosis, spinal inclination, LNG, X LNG, Y LNG, and BES were significantly associated with falls (Pfalls about lumbar lordosis angles revealed that angles of 3° and less were significant for falls. The present findings suggest that increased age, spinal inclination, LNG, X LNG, Y LNG, and decreased BES and lumbar lordosis, are associated with falls. An angle of lumbar lordosis of 3° or less was associated with falls in these community-dwelling elders. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Older persons afraid of falling reduce physical activity to prevent outdoor falls

    NARCIS (Netherlands)

    Wijlhuizen, G.J.; Jong, R. de; Hopman-Rock, M.

    2007-01-01

    Objective.: The aim of this study was to test the assumption that the level of outdoor physical activity mediates the relationship between fear of falling and actual outdoor falls according to the Task Difficulty Homeostasis Theory. Method.: A prospective follow-up study of 10 months conducted in

  15. Seniors Falls Investigative Methodology (SFIM): A Systems Approach to the Study of Falls in Seniors

    Science.gov (United States)

    Zecevic, Aleksandra A.; Salmoni, Alan W.; Lewko, John H.; Vandervoort, Anthony A.

    2007-01-01

    An in-depth understanding of human factors and human error is lacking in current research on seniors' falls. Additional knowledge is needed to understand why seniors are falling. The purpose of this article is to describe the adapting of the Integrated Safety Investigation Methodology (ISIM) (used for investigating transportation and industrial…

  16. Holocene Tsunami Deposits From Large Tsunamis Along the Kuril Subduction Zone, Northeast Japan

    Science.gov (United States)

    Nanayama, F.; Furukawa, R.; Satake, K.; Soeda, Y.; Shigeno, K.

    2003-12-01

    Holocene tsunami deposits in eastern Hokkaido between Nemuro and Tokachi show that the Kuril subduction zone repeatedly produced earthquakes and tsunamis larger than those recorded in this region since AD 1804 (Nanayama et al., Nature, 424, 660-663, 2003). Twenty-two postulated tsunami sand layers from the past 9500 years are preserved on lake bottom near Kushiro City, and about ten postulated tsunami sand layers from the past 3000 years are preserved in peat layers on the coastal marsh of Kiritappu. We dated these ten tsunami deposits (named Ts1 to Ts10 from shallower to deeper) in peat layers by radiocarbon and tephrochronology, correlated them with historical earthquakes and tsunamis, and surveyed their spatial distribution to estimate the tsunamisO inland inundation limits. Ts10 and Ts9 are under regional tephra Ta-c2 (ca. 2.5 ka) and represent prehistorical events. Ts8 to Ts5 are between two regional tephra layers Ta-c2 and B-Tm (ca. 9th century). In particular, Ts5 is found just below B-Tm, so it is dated 9th century (Heian era). Ts4 is dated ca 13th century (Kamakura era), while Ts3, found just below Us-b and Ta-b (AD 1667-1663), is dated 17th century (Edo era). Ts2 is dated 19th century (Edo era) and may correspond to the AD 1843 Tempo Tokachi-oki earthquake (Mt 8.0) recorded in a historical document Nikkanki of Kokutai-ji temple at Akkeshi. Ts1 is inferred 20th century and may correspond to the tsunami from the AD 1960 Chilean earthquake (M 9.5) or the AD 1952 Tokachi-oki earthquake (Mt 8.2). Our detailed surveys indicate that Ts3 and Ts4 can be traced more than 3 km from the present coast line in Kirittapu marsh, much longer than the limits (< 1 km) of recent deposits Ts1 and Ts2 or documented inundation of the 19th and 20th century tsunamis. The recurrence intervals of great tsunami inundation are about 400 to 500 years, longer than that of typical interplate earthquakes along the Kuril subduction zone. The longer interval and the apparent large tsunami

  17. Volcanic ash deposition and long-term vegetation change on Subantarctic Marion Island

    NARCIS (Netherlands)

    Yeloff, D.; Mauquoy, D.S.; Barber, K.; Way, S.; van Geel, B.; Turney, C.S.M.

    2007-01-01

    A c. 5500 year record of peatland development and vegetation change was generated from a core recovered from an Agrostis magellanica peat bog on subantarctic Marion Island, using palynomorph, plant macrofossil, and tephra analyses. Two tephra horizons (both 17 cm thick) were identified and dated to

  18. Research on patient safety: falls and medications.

    Science.gov (United States)

    Boddice, Sandra Dawn; Kogan, Polina

    2009-10-01

    Below you will find summaries of published research describing investigations into patient safety issues related to falls and medications. The first summary provides details on the incidence of falls associated with the use of walkers and canes. This is followed by a summary of a fall-prevention intervention study that evaluated the effectiveness of widespread dissemination of evidence-based strategies in a community in Connecticut. The third write up provides information on three classes of medications that are associated with a significant number of emergency room visits. The last summary describes a pharmacist-managed medication reconciliation intervention pilot program. For additional details about the study findings and interventions, we encourage readers to review the original articles.

  19. Deposition Measurements in NSTX

    Science.gov (United States)

    Skinner, C. H.; Kugel, H. W.; Hogan, J. T.; Wampler, W. R.

    2004-11-01

    Two quartz microbalances have been used to record deposition on the National Spherical Torus Experiment. The experimental configuration mimics a typical diagnostic window or mirror. An RS232 link was used to acquire the quartz crystal frequency and the deposited thickness was recorded continuously with 0.01 nm resolution. Nuclear Reaction Analysis of the deposit was consistent with the measurement of the total deposited mass from the change in crystal frequency. We will present measurements of the variation of deposition with plasma conditions. The transport of carbon impurities in NSTX has been modelled with the BBQ code. Preliminary calculations indicated a negligible fraction of carbon generated at the divertor plates in quiescent discharges directly reaches the outer wall, and that transient events are responsible for the deposition.

  20. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome...... ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of biomass deposits give different characteristics as compared to coal ash deposits, i.e. different physical significance of the deposition mechanisms, lower melting temperatures, etc....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  1. Falls in the elderly. I. Identification of risk factors.

    NARCIS (Netherlands)

    Bloem, B.R.; Boers, I.M.; Cramer, M.; Westendorp, R.G.J.; Gerschlager, W.

    2001-01-01

    Falls severely threaten the health of elderly persons and pose high costs to the public health service. Unfortunately, falls are often regarded as unavoidable and untreatable features of aging. Therefore, many clinicians merely treat the physical injuries of a fall. However, falls and gait

  2. Association between obesity, risk of falls and fear of falling in older women

    Directory of Open Access Journals (Sweden)

    Silvia Gonçalves Ricci Neri

    2017-11-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n4p450   The aim of this cross-sectional study was to investigate the association between obesity, risk of falls and fear of falling in older women. Two hundred and twenty-six volunteers (68.05 ± 6.22 years, 68.06 ± 11.79 kg, 1.56 ± 0.06 m were classified as normal weight, overweight or obese, according to the body mass index. Risk of falls and fear of falling were evaluated using QuickScreen Clinical Falls Risk Assessment and Falls Efficiency Scale – International (FES-I, respectively. Comparisons between groups were conducted using Chi-square and ANOVA One-way tests. The significance level was set at p< 0.05. Obesity was associated with greater probability of falls (p< 0.001, which may be partly explained by decreased muscle strength (p< 0.001 and reaction time (p< 0.001. In addition, significant differences between groups was observed in FES-I score (p< 0.01, with obese women showing more pronounced fear of falling (30.10 ± 8.4 than normal weigh (25. 33 ± 7.11, p< 0.01 and overweight subjects (26.97 ± 7.05, p< 0.05. These findings corroborate previous evidence pointing obesity as a major risk factor for falls. Therefore, health professionals dealing with fall prevention should consider the effects of overweight.

  3. Uraniferous surficial deposits

    International Nuclear Information System (INIS)

    Toens, P.D.; Hambleton-Jones, B.B.

    1980-10-01

    As a result of the discovery of uranium in surficial deposits of Tertiary to Recent age, in Australia and Southern Africa, increasing attention is being paid to the location and understanding of the genesis of these deposits. The paper discusses the definitions and terminology currently in use and a classification of these deposits is presented. It is concluded that in order to obtain a measure of clarity, the terms calcrete, gypcrete and dolocrete should not be used to describe the uraniferous valley-fill deposits of Southern Africa and Australia [af

  4. Falls and fear of falling predict future falls and related injuries in ambulatory individuals with spinal cord injury: a longitudinal observational study.

    Science.gov (United States)

    Jørgensen, Vivien; Butler Forslund, Emelie; Opheim, Arve; Franzén, Erika; Wahman, Kerstin; Hultling, Claes; Seiger, Åke; Ståhle, Agneta; Stanghelle, Johan K; Roaldsen, Kirsti S

    2017-04-01

    What is the 1-year incidence of falls and injurious falls in a representative cohort of community-dwelling ambulatory individuals with chronic spinal cord injury? What are the predictors of recurrent falls (more than two/year) and injurious falls in this population? One-year longitudinal observational multi-centre study. A representative sample of 68 (of 73 included) community-dwelling ambulatory individuals with traumatic SCI attending regular follow-up programs at rehabilitation centres. Primary outcome measures were incidence and predictors of recurrent falls (more than two/year) and injurious falls reported every 2 weeks for 1year. A total of 48% of participants reported recurrent falls. Of the 272 reported falls, 41% were injurious. Serious injuries were experienced by 4% of participants, all of whom were women. Multivariate logistic regression analysis showed that recurrent falls in the previous year (OR=111, 95% CI=8.6 to 1425), fear of falling (OR=6.1, 95% CI=1.43 to 26) and longer time taken to walk 10m (OR=1.3, 95% CI=1.0 to 1.7) were predictors of recurrent falls. Fear of falling (OR=4.3, 95% CI=1.3 to 14) and recurrent falls in the previous year (OR=4.2, 95% CI=1.2 to 14) were predictors of injurious falls. Ambulatory individuals have a high risk of falling and of fall-related injuries. Fall history, fear of falling and walking speed could predict recurrent falls and injurious falls. Further studies with larger samples are needed to validate these findings. [Jørgensen V, Butler Forslund E, Opheim A, Franzén E, Wahman K, Hultling C, Seiger Å, Ståhle A, Stanghelle JK, Roaldsen KS (2017) Falls and fear of falling predict future falls and related injuries in ambulatory individuals with spinal cord injury: a longitudinal observational study. Journal of Physiotherapy 63: 108-113]. Copyright © 2017 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

  5. Jökulhlaup deposits in proglacial areas

    Science.gov (United States)

    Maizels, Judith

    This paper discusses the main causes and characteristics of jökulhlaup ('glacier burst') floods, and explores the extent to which they generate depositional landform and sediment assemblages that are distinct from those of 'normal', braided river outwash ('Type I' outwash). Two main jökulhlaup outwash environments are identified: Type II outwash, produced by sudden drainage of ice-dammed lakes; and Type III, associated with drainage during subglacial geothermal activity, and distinguished by deposits resulting from high sediment concentrations and hyperconcentrated flows. In fluid flows, especially ones yielding Type II outwash, the most common deposits are large-scale expansion bars (and locally, eddy and pendant bars), and 'mega-ripples' or dunes, both forms normally composed of large-scale gravel-cobble cross-bedding, often capped by an imbricated boulder lag (a 'Type B2' lithofacies sequence). The armour is absent only where runoff decreased too rapidly to allow surface winnowing. Other jökulhlaup facies include extensive boulder beds (Type C), inverse-normally graded cobble beds (Type DS), ice-proximal debris flow deposits and deformed bedding containing diamicton clasts (Types G and H), and slack-water sediments (Type A). Type III outwash is dominated by massive, homogeneous, flood surge granules, underlain by pre-surge gravels, and capped by post-surge fluid bedforms, reflecting deposition during both the rising and falling limbs of the flood hydrograph (Type E4). The paper demonstrates that jökulhlaups do generate distinctive assemblages of depositional landforms and sediments, and concludes with a model of the dominant lithofacies sequences and associated landforms in proglacial environments subject to jökulhlaup drainage.

  6. Fall Risk Assessment Predicts Fall-Related Injury, Hip Fracture, and Head Injury in Older Adults.

    Science.gov (United States)

    Nilsson, Martin; Eriksson, Joel; Larsson, Berit; Odén, Anders; Johansson, Helena; Lorentzon, Mattias

    2016-11-01

    To investigate the role of a fall risk assessment, using the Downton Fall Risk Index (DFRI), in predicting fall-related injury, fall-related head injury and hip fracture, and death, in a large cohort of older women and men residing in Sweden. Cross sectional observational study. Sweden. Older adults (mean age 82.4 ± 7.8) who had a fall risk assessment using the DFRI at baseline (N = 128,596). Information on all fall-related injuries, all fall-related head injuries and hip fractures, and all-cause mortality was collected from the Swedish Patient Register and Cause of Death Register. The predictive role of DFRI was calculated using Poisson regression models with age, sex, height, weight, and comorbidities as covariates, taking time to outcome or end of study into account. During a median follow-up of 253 days (interquartile range 90-402 days) (>80,000 patient-years), 15,299 participants had a fall-related injury, 2,864 a head injury, and 2,557 a hip fracture, and 23,307 died. High fall risk (DFRI ≥3) independently predicted fall-related injury (hazard ratio (HR) = 1.43, 95% confidence interval (CI) = 1.39-1.49), hip fracture (HR = 1.51, 95% CI =1.38-1.66), head injury (HR = 1.12, 95% CI = 1.03-1.22), and all-cause mortality (HR = 1.39, 95% CI = 1.35-1.43). DFRI more strongly predicted head injury (HR = 1.29, 95% CI = 1.21-1.36 vs HR = 1.08, 95% CI = 1.04-1.11) and hip fracture (HR = 1.41, 95% CI = 1.30-1.53 vs HR = 1.08, 95% CI = 1.05-1.11) in 70-year old men than in 90-year old women (P Fall risk assessment using DFRI independently predicts fall-related injury, fall-related head injury and hip fracture, and all-cause mortality in older men and women, indicating its clinical usefulness to identify individuals who would benefit from interventions. © 2016 The Authors. The Journal of the American Geriatrics Society published by Wiley Periodicals, Inc. on behalf of The American Geriatrics Society.

  7. [Risk factors for falls and survival after falling in elderly people in a community].

    Science.gov (United States)

    Kato, Ryuichi; Takagi, Chika; Sakurai, Naoko; Hoshi, Tanji

    2012-05-01

    The purpose of this study was to assess the risk factors associated with falls and to examine the effects of falls on survival of elderly people in a community. A questionnaire survey was conducted in 16,462 urban elderly dwellers aged 65 years or more in City A in September 2001. A follow-up survey was carried out in September 2004. We analyzed the data of 8,285 subjects who answered both questionnaires and had not relocated by August 2007. Baseline assessments of health and functioning were carried out in 2001. Falls experienced during the 1-year period before September 2004 were recorded, and the deaths were recorded until August 2007. Statistical analysis was performed using a logistic regression model and Cox's proportional hazards analysis. A total of 6,420 subjects (3,127 men and 3,293 women) who had provided complete answers about their falls were included in the analyses. Of these, 27.8% of women and 16.4% of men had experienced falls, while 6.2% of women and 2.1% of men had experienced falls that caused fractures. We found that the likelihood of fall, with or without fracture development, was greater in women than in men (P falls tended to increase with age in both women and men. Risk factors associated with falls, in addition to age and gender, were pain (odds ratio [OR], 1.75), lack of instrumental activities of daily living (IADL; OR, 1.45), poor self-rated health status (OR, 1.42), and presence of disease (OR, 1.35). Risk factors associated with falls that caused fracture were pain (OR, 1.85) and lack of IADL (OR, 1.61). Cox's proportional hazards analysis showed a significant increase in mortality in both men and women who had experienced falls than in those who had not (hazard ratio [HR], 1.94, 1.43). Aging, pain and disease, lack of IADL, and poor self-rated health status were all significant risk factors for falls in elderly people, and a fall was related to subsequent mortality.

  8. What are the Main Physical Functioning Factors Associated With Falls Among Older People With Different Perceived Fall Risk?

    Science.gov (United States)

    Moreira, Mirian N; Bilton, Tereza L; Dias, Rosangela C; Ferriolli, Eduardo; Perracini, Monica R

    2017-07-01

    Fall risk perceptions may influence the judgement over physical and functional competencies to avoid falls. However, few studies have explored the physical functioning characteristics associated with falls among older people with low perceived fall risk. This study aimed to identify the prevalence of falls and physical functioning factors associated with falling among community-dwelling older adults with low and high perceived fall risk. We conducted a cross-sectional population based study with 773 community-dwelling elders. Perceived fall risk was investigated using Falls Efficacy Scale International. We considered fallers those who reported at least one fall in the previous 12 months. Physical functioning measures used were grip strength, usual gait speed, sit-to-stand test, five step test, timed up and go test, one-legged stance test, anterior and lateral functional reach test. At least one fall was reported by 103 (30%) participants with low perceived fall risk and by 196 (46%) participants with high perceived fall risk. The odds of falling were lower among those with greater grip strength and with a greater stance time in one-legged test, and the odds of falling among elders with high perceived fall risk were higher among those who took more time in performing the five step test. We believe that our results highlight the need of not neglecting the risk of falls among active older adults with low perceived fall risk, particularly in those elders that show reduced stability in a small base of support and a lower leg strength. In addition, we suggest that elders with high perceived fall risk should be assessed using anticipatory postural adjustment tests. Particularly, our results may help physiotherapists to identify eligible elders with different perceptions of fall risk for tailored interventions aimed at reducing falls. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Impact of falls and fear of falling on health-related quality of life in patients with Parkinson's disease

    NARCIS (Netherlands)

    Grimbergen, Y.A.M.; Schrag, A.; Mazibrada, G.; Borm, G.F.; Bloem, B.R.

    2013-01-01

    Postural instability, recurrent falls and fear of falling are common in advanced Parkinson's disease (PD). We examined the impact of fall frequency, fear of falling, balance confidence and objectively measured balance impairment (using Tinetti's Mobility Index) on health-related quality of life

  10. Ichnological evidence of jökulhlaup deposit recolonization from the Touchet Beds, Mabton, WA, USA

    Science.gov (United States)

    MacEachern, James A.; Roberts, Michael C.

    2013-01-01

    The late Wisconsinan Touchet Beds section at Mabton, Washington reveals at least seven stacked jökulhlaup deposits, five showing evidence of post-flood recolonization by vertebrates. Tracemakers are attributed to voles or pocket mice (1-3 cm diameter burrows) and pocket gophers or ground squirrels (3-6 cm diameter burrows). The Mount St. Helens S tephra deposited between flood beds contains the invertebrate-generated burrows Naktodemasis and Macanopsis. Estimates of times between floods are based on natal dispersal distances of the likely vertebrate tracemakers (30-50 m median distances; 127-525 m maximum distances) from upland areas containing surviving populations to the Mabton area, a distance of about 7.9 km. Tetrapods would have required at least two to three decades to recolonize these flood beds, based on maximum dispersal distances. Invertebrate recolonization was limited by secondary succession and estimated at only a few years to a decade. These ichnological data support multiple floods from failure of the ice dam at glacial Lake Missoula, separated by hiatal surfaces on the order of decades in duration. Ichnological recolonization times are consistent with published estimates of refill times for glacial Lake Missoula, and complement the other field evidence that points to repeated, autogenically induced flood discharge.

  11. [Muscle and bone health as a risk factor of fall among the elderly. Kaigoyobou and prevention of falling].

    Science.gov (United States)

    Obuchi, Shuichi

    2008-06-01

    Kaigoyobou, prevention of long-term care use, is a comprehensive approach, including physical, nutritional, and social, to maintain independent living in the elderly. Prevention of falling is one useful method of Kaigoyobou. From literature review, post-fall syndrome should be primarily eliminated in the elderly since falling rate of the elderly with the falling history reported significantly greater falling rate than the other community dwelling elderly. The ability to avoid falling when they trip or slip during walking may be the most important physical function needed to be intervened. In order to train elderly person successfully, nutritional intervention need to be considered into fall prevention program.

  12. iFall: an Android application for fall monitoring and response.

    Science.gov (United States)

    Sposaro, Frank; Tyson, Gary

    2009-01-01

    Injuries due to falls are among the leading causes of hospitalization in elderly persons, often resulting in a rapid decline in quality of life or death. Rapid response can improve the patients outcome, but this is often lacking when the injured person lives alone and the nature of the injury complicates calling for help. This paper presents an alert system for fall detection using common commercially available electronic devices to both detect the fall and alert authorities. We use an Android-based smart phone with an integrated tri-axial accelerometer. Data from the accelerometer is evaluated with several threshold based algorithms and position data to determine a fall. The threshold is adaptive based on user provided parameters such as: height, weight, and level of activity. The algorithm adapts to unique movements that a phone experiences as opposed to similar systems which require users to mount accelerometers to their chest or trunk. If a fall is suspected a notification is raised requiring the user's response. If the user does not respond, the system alerts pre-specified social contacts with an informational message via SMS. If a contact responds the system commits an audible notification, automatically connects, and enables the speakerphone. If a social contact confirms a fall, an appropriate emergency service is alerted. Our system provides a realizable, cost effective solution to fall detection using a simple graphical interface while not overwhelming the user with uncomfortable sensors.

  13. The history of falls and the association of the timed up and go test to falls and near-falls in older adults with hip osteoarthritis

    Directory of Open Access Journals (Sweden)

    Faulkner Robert A

    2007-07-01

    Full Text Available Abstract Background Falling accounts for a significant number of hospital and long-term care admissions in older adults. Many adults with the combination of advancing age and functional decline associated with lower extremity osteoarthritis (OA, are at an even greater risk. The purpose of this study was to describe fall and near-fall history, location, circumstances and injuries from falls in a community-dwelling population of adults over aged 65 with hip OA and to determine the ability of the timed up and go test (TUG to classify fallers and near-fallers. Method A retrospective observational study of 106 older men and women with hip pain for six months or longer, meeting a clinical criteria for the presence of hip OA at one or both hips. An interview for fall and near-fall history and administration of the TUG were administered on one occasion. Results Forty-five percent of the sample had at least one fall in the past year, seventy-seven percent reported occasional or frequent near-falls. The majority of falls occurred during ambulation and ascending or descending steps. Forty percent experienced an injury from the fall. The TUG was not associated with history of falls, but was associated with near-falls. Higher TUG scores occurred for those who were older, less mobile, and with greater number of co-morbidities. Conclusion A high percentage of older adults with hip OA experience falls and near-falls which may be attributed to gait impairments related to hip OA. The TUG could be a useful screening instrument to predict those who have frequent near-falls, and thus might be useful in predicting risk of future falls in this population.

  14. Montana Advanced Biofuels Great Falls Approval

    Science.gov (United States)

    This November 20, 2015 letter from EPA approves the petition from Montana Advanced Biofuels, LLC, Great Falls facility, regarding ethanol produced through a dry mill process, qualifying under the Clean Air Act for advanced biofuel (D-code 5) and renewable

  15. Student Time Usage during Fall Reading Week

    Science.gov (United States)

    Cramer, Ken; Pschibul, Rebecca

    2017-01-01

    The present study investigated the time usage and levels of perceived stress, academic workload, and recreation time for 177 students at the University of Windsor before, during, and after Fall Reading Week (FRW). Over a three-week span (at various times of the day), students received a message to their smartphone to complete a 20-second survey…

  16. Falls Prevention: Unique to Older Adults

    Science.gov (United States)

    ... may lead to malnutrition, which is a risk factor for increased risk of falling. For example, as you age, you may: have illnesses that make it hard to shop for and prepare food (such as arthritis or Alzheimer’s disease ) be housebound have difficulty chewing because of ...

  17. Wireless Falling Detection System Based on Community.

    Science.gov (United States)

    Xia, Yun; Wu, Yanqi; Zhang, Bobo; Li, Zhiyang; He, Nongyue; Li, Song

    2015-06-01

    The elderly are more likely to suffer the aches or pains from the accidental falls, and both the physiology and psychology of patients would subject to a long-term disturbance, especially when the emergency treatment was not given timely and properly. Although many methods and devices have been developed creatively and shown their efficiency in experiments, few of them are suitable for commercial applications routinely. Here, we design a wearable falling detector as a mobile terminal, and utilize the wireless technology to transfer and monitor the activity data of the host in a relatively small community. With the help of the accelerometer sensor and the Google Mapping service, information of the location and the activity data will be send to the remote server for the downstream processing. The experimental result has shown that SA (Sum-vector of all axes) value of 2.5 g is the threshold value to distinguish the falling from other activities. A three-stage detection algorithm was adopted to increase the accuracy of the real alarm, and the accuracy rate of our system was more than 95%. With the further improvement, the falling detecting device which is low-cost, accurate and user-friendly would become more and more common in everyday life.

  18. A new view on falling aprons

    NARCIS (Netherlands)

    Verhagen, H.J.; Van der Hoeven, M.; Thiel, B.

    2003-01-01

    In a flume of BallastHam Dredging a falling apron model has been constructed and loaded by current. The tests have been done with different rock sizes, different layer thickness of the top storage of the apron and two different gradings. In summary it was found that for both the narrow graded rock

  19. Early Childhood: Fall Harvest and Science.

    Science.gov (United States)

    Science and Children, 1982

    1982-01-01

    Provides instructional strategies for using fall fruits/vegetables in science lessons, including activities related to melons, pumpkins, grapes, pears, squash, and yams. Suggests extending the activities over a month or more to allow children time to explore and investigate. (JN)

  20. Delayed Capillary Breakup of Falling Viscous Jets

    NARCIS (Netherlands)

    Javadi, A.; Eggers, J.; Bonn, D.; Habibi, M.; Ribe, N.M.

    2013-01-01

    Thin jets of viscous fluid like honey falling from capillary nozzles can attain lengths exceeding 10 m before breaking up into droplets via the Rayleigh-Plateau (surface tension) instability. Using a combination of laboratory experiments and WKB analysis of the growth of shape perturbations on a jet

  1. Risk of fall in patients with COPD.

    Science.gov (United States)

    Hakamy, Ali; Bolton, Charlotte E; Gibson, Jack E; McKeever, Tricia M

    2018-03-21

    A matched cohort study was conducted to determine the incidence of falls in patients following a diagnosis of COPD using a UK primary care database. 44 400 patients with COPD and 175 545 non-COPD subjects were identified. The incidence rate of fall per 1000 person-years in patients with COPD was higher (44.9; 95% CI 44.1 to 45.8) compared with non-COPD subjects (24.1; 95% CI 23.8 to 24.5) (P<0.0001). Patients with COPD were 55% more likely to have an incident record of fall than non-COPD subjects (adjusted HR, 1.55; 95% CI 1.50 to 1.59). The greater falls risk in patients with COPD needs consideration and modifiable factors addressed. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  2. AEGIS at CERN: Measuring Antihydrogen Fall

    CERN Document Server

    Giammarchi, Marco G.

    2011-01-01

    The main goal of the AEGIS experiment at the CERN Antiproton Decelerator is the test of fundamental laws such as the Weak Equivalence Principle (WEP) and CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be formed whose fall in the gravitational field is measured in a Moire' deflectometer; this will constitute the first test of the WEP with antimatter.

  3. Does Fall History Influence Residential Adjustments?

    Science.gov (United States)

    Leland, Natalie; Porell, Frank; Murphy, Susan L.

    2011-01-01

    Purpose of the study: To determine whether reported falls at baseline are associated with an older adult's decision to make a residential adjustment (RA) and the type of adjustment made in the subsequent 2 years. Design and Methods: Observations (n = 25,036) were from the Health and Retirement Study, a nationally representative sample of…

  4. Preventing Older Adult Falls and TBI

    Centers for Disease Control (CDC) Podcasts

    2008-03-05

    This podcast provides tips on how older adults can prevent falls and related injuries, such as traumatic brain injuries (TBI).  Created: 3/5/2008 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 3/7/2008.

  5. Falling balls and simple shearing strain

    International Nuclear Information System (INIS)

    Brun, J L; Pacheco, A F

    2006-01-01

    The problem of particles falling under gravity allows us to relate Hamiltonian mechanics to such different subjects as elasticity and fluid mechanics. It is with this in mind that mechanics gives us the opportunity of introducing, in a rather simple and unusual form, some concepts such as vorticity, the incompressibility condition or simple shear strain to physics students at the undergraduate level

  6. Water supply impacts of nuclear fall

    International Nuclear Information System (INIS)

    Hobbs, B.F.; Luo, Y.; Maciejowski, M.E.; Chester, C.V.

    1989-01-01

    “Nuclear winter,” more properly called “nuclear fall,” could be caused by injection of large amounts of dust into the atmosphere. Besides causing a decrease in temperature, it could be accompanied by “nuclear drought,” a catastrophic decrease in precipitation. Dry land agriculture would then be impossible, and municipal, industrial, and irrigation water supplies would be diminished. It has been argued that nuclear winter/fall poses a much greater threat to human survival than do fall out or the direct impacts of a conflict. However, this does not appear to be true, at least for the U.S. Even under the unprecedented drought that could result from nuclear fall, water supplies would be available for many essential activities. For the most part, ground water supplies would be relatively invulnerable to nuclear drought, and adequate surface supplies would be available for potable uses. This assumes that conveyance facilities and power supplies survive a conflict largely intact or can be repaired

  7. A simple strategy for fall events detection

    KAUST Repository

    Harrou, Fouzi; Zerrouki, Nabil; Sun, Ying; Houacine, Amrane

    2017-01-01

    the multivariate exponentially weighted moving average (MEWMA) control chart to detect fall events. Towards this end, a set of ratios for five partial occupancy areas of the human body for each frame are collected and used as the input data to MEWMA chart

  8. Anode Fall Formation in a Hall Thruster

    International Nuclear Information System (INIS)

    Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.

    2004-01-01

    As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed

  9. Protect the Ones You Love From Falls

    Centers for Disease Control (CDC) Podcasts

    2008-12-10

    This podcast, developed as part of the Protect the Ones You Love initiative, discusses steps parents can take to help protect their children from falls, one of the leading causes of child injury.  Created: 12/10/2008 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 12/10/2008.

  10. Things Come Together with "Things Fall Apart."

    Science.gov (United States)

    Puhr, Kathleen M.

    1987-01-01

    Recommends using C. Achebe's English language novel, "Things Fall Apart," in a unit on tragedy. Provides plot summary and topics for discussion of cultural values and socialization. Notes that besides illustrating character traits, themes and plot structure of the tragic genre, the novel provides an opportunity for learning Nigerian…

  11. Have a Safe and Healthy Fall

    Centers for Disease Control (CDC) Podcasts

    2010-10-14

    Fall is a great time to try new and healthy activities with your parents! Have a food tasting or a leaf raking contest! Whatever your plans, make sure to have fun and be safe!  Created: 10/14/2010 by CDC Office of Women’s Health.   Date Released: 10/14/2010.

  12. Atmospheric Deposition of Pb, Zn, Cu, and Cd in Amman, Jordan

    International Nuclear Information System (INIS)

    Momani, K.A.; Jiries, A.G.; Jaradat, Q.M.

    1999-01-01

    Atmospheric samples were collected by high-volume air sampler and dust fall containers during the summer of 1995 at different sites in Amman City, Jordan. Heavy metal contents in settle able (dust fall) as well as in air particulates (suspended) were analyzed by graphite furnace atomic absorption spectrophotometry. The atmospheric concentrations of Zn, Cu, Pb, and Cd were 344, 170, 291, and 3.8 ng/m 3 , respectively. On the other hand, the levels of these elements in dust fall deposition were 505, 94, 74, and 3.1 μg/g, respectively. The fluxes and dry deposition velocities of these heavy metals were determined and compared with the findings of other investigators worldwide. Significant enrichment coefficients of heavy metals in dust fall were observed. The enrichment coefficients were 12.1, 6.1, 11.7, and 1.1 for Zn, Cu, Pb, and Cd, respectively

  13. Prevention of falls in nursing homes: subgroup analyses of a randomized fall prevention trial.

    Science.gov (United States)

    Rapp, Kilian; Lamb, Sarah E; Büchele, Gisela; Lall, Ranjit; Lindemann, Ulrich; Becker, Clemens

    2008-06-01

    To evaluate the effectiveness of a multifactorial fall prevention program in prespecified subgroups of nursing home residents. Secondary analysis of a cluster-randomized, controlled trial. Six nursing homes in Germany. Seven hundred twenty-five long-stay residents; median age 86; 80% female. Staff and resident education on fall prevention, advice on environmental adaptations, recommendation to wear hip protectors, and progressive balance and resistance training. Time to first fall and the number of falls. Falls were assessed during the 12-month intervention period. Univariate regression analyses were performed, including a confirmatory test of interaction. The intervention was more effective in people with cognitive impairment (hazard ratio (HR)=0.49, 95% confidence interval (CI)=0.35-0.69) than in those who were cognitively intact (HR=0.91, 95% CI=0.68-1.22), in people with a prior history of falls (HR=0.47, 95% CI=0.33-0.67) than in those with no prior fall history (HR=0.77, 95% CI=0.58-1.01), in people with urinary incontinence (HR=0.59, 95% CI=0.45-0.77) than in those with no urinary incontinence (HR=0.98, 95% CI=0.68-1.42), and in people with no mood problems (incidence rate ratio (IRR)=0.41, 95% CI=0.27-0.61) than in those with mood problems (IRR=0.74, 95% CI=0.51-1.09). The effectiveness of a multifactorial fall prevention program differed between subgroups of nursing home residents. Cognitive impairment, a history of falls, urinary incontinence, and depressed mood were important in determining response.

  14. Fall-Prone Older People's Attitudes towards the Use of Virtual Reality Technology for Fall Prevention.

    Science.gov (United States)

    Dockx, Kim; Alcock, Lisa; Bekkers, Esther; Ginis, Pieter; Reelick, Miriam; Pelosin, Elisa; Lagravinese, Giovanna; Hausdorff, Jeffrey M; Mirelman, Anat; Rochester, Lynn; Nieuwboer, Alice

    2017-01-01

    Virtual reality (VR) technology is a relatively new rehabilitation tool that can deliver a combination of cognitive and motor training for fall prevention. The attitudes of older people to such training are currently unclear. This study aimed to investigate: (1) the attitudes of fall-prone older people towards fall prevention exercise with and without VR; (2) attitudinal changes after intervention with and without VR; and (3) user satisfaction following fall prevention exercise with and without VR. A total of 281 fall-prone older people were randomly assigned to an experimental group receiving treadmill training augmented by VR (TT+VR, n = 144) or a control group receiving treadmill training alone (TT, n = 137). Two questionnaires were used to measure (1) attitudes towards fall prevention exercise with and without VR (AQ); and (2) user satisfaction (USQ). AQ was evaluated at baseline and after intervention. USQ was measured after intervention only. The AQ revealed that most participants had positive attitudes towards fall prevention exercise at baseline (82.2%) and after intervention (80.6%; p = 0.144). In contrast, only 53.6% were enthusiastic about fall prevention exercise with VR at baseline. These attitudes positively changed after intervention (83.1%; p < 0.001), and 99.2% indicated that they enjoyed TT+VR. Correlation analyses showed that postintervention attitudes were strongly related to user satisfaction (USQ: r = 0.503; p < 0.001). Older people's attitudes towards fall prevention exercise with VR were positively influenced by their experience. From the perspective of the user, VR is an attractive training mode, and thus improving service provision for older people is important. © 2017 S. Karger AG, Basel.

  15. Multimorbidity predicts falls differentially according to the type of fall in postmenopausal women.

    Science.gov (United States)

    Afrin, Nadia; Honkanen, Risto; Koivumaa-Honkanen, Heli; Lukkala, Pyry; Rikkonen, Toni; Sirola, Joonas; Williams, Lana J; Kröger, Heikki

    2016-09-01

    To ascertain whether the risk of falls of different types is related to morbidity (number of chronic medical conditions) among postmenopausal women. This cohort study uses data from a population-based prospective cohort study (OSTPRE). The study population consisted of 10,594 women aged 47-56 years living in Kuopio Province, Eastern Finland, in 1989, who responded to postal enquiries at both baseline and 5-year follow-up, in 1994. Morbidity (i.e. number of diagnosed chronic medical conditions) was reported in 1989 and falls in 1994. Falls were categorized as slip or nonslip, and 'frequent falls' was defined as two or more in a 12-month period. The risk (odds ratio (OR) with 95% CI) of a fall increased with the number of chronic medical conditions. The OR was 1.28 (1.17-1.40) for those with 1-2 conditions and 1.41 (1.24-1.60) for those with multimorbidity (≥3 conditions) compared with healthy respondents. Multimorbidity was associated with a greater risk of the woman experiencing frequent nonslip falls (OR=2.57; 2.01-3.29) than frequent slip falls (OR=1.46; 1.17-1.80). Adjusting with logistic regression for age, number of medications and smoking did not affect the risk estimates. Multimorbidity has a much smaller effect on slip than on nonslip falls in postmenopausal women. This should be taken into account when investigating the effects of multimorbidity on fall risk in varying weather conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. MAPLE deposition of nanomaterials

    International Nuclear Information System (INIS)

    Caricato, A.P.; Arima, V.; Catalano, M.; Cesaria, M.; Cozzoli, P.D.; Martino, M.; Taurino, A.; Rella, R.; Scarfiello, R.; Tunno, T.; Zacheo, A.

    2014-01-01

    The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

  17. MAPLE deposition of nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Caricato, A.P., E-mail: annapaola.caricato@le.infn.it [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Arima, V.; Catalano, M. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Cesaria, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Cozzoli, P.D. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Martino, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Taurino, A.; Rella, R. [Institute for Microelectronics and Microsystems, IMM-CNR, Via Monteroni, I-73100 Lecce (Italy); Scarfiello, R. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Tunno, T. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Zacheo, A. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy)

    2014-05-01

    The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

  18. Aquatic chemistry of acid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Stumm, W; Sigg, L; Schnoor, J L

    1987-01-01

    The occurrence of acid precipitation in many regions of the Northern hemisphere is a consequnece of human interference in the cycles that unite land, water and atmosphere. The oxidation of carbon, sulfur and nitrogen, resulting mostly from fossil fuel burning, rivals oxidation processes induced by photosynthesis and respiration and disturbs redox conditions in the atmosphere. The paper discusses oxidation-reduction reactions, particularly those involving atmospheric pollutants that are important in the formation of acid precipitation. Topics covered are: a stoichiometric model of acid rain formation; sulfur dioxide and ammonia adsorption; acid neutralizing capacity. The paper concludes that explanations of simple chemical equilibria between gases and water aid our understanding of how acidifying gases become dissolved in cloud water, in droplets of falling rain, or in fog. Rigorous definitions of base- or acid-neutralizing capacities are prerequisites to measuring and interpreting residual acidity in dry and wet deposition and for assessing the disturbance caused by the transfer of acid to terrestrial and aquatic ecosystems. 20 references.

  19. Exploring the relationship between fall risk-increasing drugs and fall-related fractures.

    Science.gov (United States)

    De Winter, Sabrina; Vanwynsberghe, Sarah; Foulon, Veerle; Dejaeger, Eddy; Flamaing, Johan; Sermon, An; Van der Linden, Lorenz; Spriet, Isabel

    2016-04-01

    Hospital admissions due to fall-related fractures are a major problem in the aging population. Several risk factors have been identified, including drug use. Most studies often retrieved prescription-only drugs from national databases. These are associated with some limitations as they do not always reliably reproduce the complete patient's active drug list. To evaluate the association between the number of FRIDs intake identified by a standardised medication reconciliation process and a fall-related fracture leading to a hospital admission in older adults. The first cohort has been recruited from one traumatology ward of a tertiary teaching hospital in Belgium and the second cohort has been recruited from 11 community pharmacies in Belgium. A prospective study with two individually matched cohorts was performed. Adult patients (≥75 years) admitted with an injury due to a fall were included in the first cohort (faller group). The second cohort consisted of patients who did not suffer from a fall within the last 6 months (non-faller group). Matching was performed for age, gender, place of residence and use of a walking aid. In both groups, clinical pharmacists and undergraduate pharmacy students obtained the medication history, using a standardised approach. A list of drugs considered to increase the risk of falling was created. It included cardiovascular drugs and drugs acting on the nervous system. A linear mixed model was used to compare the number of fall risk-increasing drugs between fallers and non-fallers. The number of fall risk-increasing drugs in a faller versus a non-faller group. Sixty-one patients were matched with 121 non-fallers. Patients received on average 3.1 ± 2.1 and 3.2 ± 1.8 fall risk-increasing drugs in the faller and in the non-faller group, respectively. The mean number of fall risk-increasing drugs was comparable in both groups (p = 0.844), even after adjusting for alcohol consumption, fear of falling, vision and foot problems (p = 0

  20. The Effects of the A Matter of Balance Program on Falls and Physical Risk of Falls, Tampa, Florida, 2013

    OpenAIRE

    Chen, Tuo-Yu; Edwards, Jerri D.; Janke, Megan C.

    2015-01-01

    Introduction This study investigated the effects of the A Matter of Balance (MOB) program on falls and physical risk factors of falling among community-dwelling older adults living in Tampa, Florida, in 2013. Methods A total of 110 adults (52 MOB, 58 comparison) were enrolled in this prospective cohort study. Data on falls, physical risk of falling, and other known risk factors of falling were collected at baseline and at the end of the program. Multivariate analysis of covariance with repeat...

  1. Impact of fear of falling and fall history on disability incidence among older adults: Prospective cohort study.

    Science.gov (United States)

    Makino, Keitaro; Makizako, Hyuma; Doi, Takehiko; Tsutsumimoto, Kota; Hotta, Ryo; Nakakubo, Sho; Suzuki, Takao; Shimada, Hiroyuki

    2018-04-01

    Fear of falling (FOF) is a major health problem for older adults, present not just in fallers, but also nonfallers. This study examined the impact of FOF and fall history on disability incidence among community-dwelling older adults from a prospective cohort study. A total of 5104 older adults living in community settings participated in baseline assessment and were followed up for about 4 years (median 52 mo, range 49-55 mo). At baseline, participants were assessed the presence of FOF and their fall history, and divided into 4 groups: Fall (-) FOF (-), Fall (+) FOF (-), Fall (-) FOF (+), and Fall (+) FOF (+). Disability incidence was defined as national long-term care insurance certification for personal support or care. During the follow-up period, 429 participants (9.9%) were newly certified as having a disability and needing personal support for long-term care insurance. Fall (-) FOF (+) group and Fall (+) FOF (+) group showed a significantly higher risk of disability incidence than Fall (-) FOF (-) group even after adjusting for covariates (Fall (-) FOF (+): hazard ratio 1.28, 95% confidence interval, 1.01-1.62, Fall (+) FOF (+): hazard ratio 1.44, 95% confidence interval, 1.05-1.98). Fear of falling could be a simple and useful predictor of disability incidence in community-dwelling older adults. Identifying and decreasing fall risk factors may prevent fall-related injuries, but excessive FOF may be associated with increased risk of disability incidence. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Laser ablation deposition measurements from silver and nickel

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith; Ellegaard, Ole; Schou, Jørgen

    1996-01-01

    The deposition rate for laser ablated metals has been studied in a standard geometry for fluences up to 20 J/cm(2). The rate for silver and nickel is a few percent of a monolayer per pulse at the laser wavelengths 532 nm and 355 nm. The rate for nickel is significantly higher than that for silver...... at 532 nm, whereas the rate for the two metals is similar at 355 nm. This behaviour disagrees with calculations based on the thermal properties at low intensities as well as predictions based on formation of an absorbing plasma at high intensities. The deposition rate falls strongly with increasing...

  3. Reducing falls and improving mobility in multiple sclerosis.

    Science.gov (United States)

    Sosnoff, Jacob J; Sung, JongHun

    2015-06-01

    Falls are common in persons with multiple sclerosis (MS), and are related to physical injury and reduce the quality of life. Mobility impairments are a significant risk factor for falls in persons with MS. Although there is evidence that mobility in persons with MS can be improved with rehabilitation, much less is known about fall prevention. This review focuses on fall prevention in persons with MS. Ten fall prevention interventions consisting of 524 participants with a wide range of disability were systematically identified. Nine of the 10 investigations report a reduction in falls and/or proportion of fallers following treatment. The vast majority observed an improvement in balance that co-occurred with the reduction in falls. Methodological limitations preclude any firm conclusions. Numerous gaps in the understanding of fall prevention in persons with MS are discussed. Well-designed randomized control trials targeting mobility and falls are warranted.

  4. A Wavelet-Based Approach to Fall Detection

    Directory of Open Access Journals (Sweden)

    Luca Palmerini

    2015-05-01

    Full Text Available Falls among older people are a widely documented public health problem. Automatic fall detection has recently gained huge importance because it could allow for the immediate communication of falls to medical assistance. The aim of this work is to present a novel wavelet-based approach to fall detection, focusing on the impact phase and using a dataset of real-world falls. Since recorded falls result in a non-stationary signal, a wavelet transform was chosen to examine fall patterns. The idea is to consider the average fall pattern as the “prototype fall”.In order to detect falls, every acceleration signal can be compared to this prototype through wavelet analysis. The similarity of the recorded signal with the prototype fall is a feature that can be used in order to determine the difference between falls and daily activities. The discriminative ability of this feature is evaluated on real-world data. It outperforms other features that are commonly used in fall detection studies, with an Area Under the Curve of 0.918. This result suggests that the proposed wavelet-based feature is promising and future studies could use this feature (in combination with others considering different fall phases in order to improve the performance of fall detection algorithms.

  5. Assessment of risk of falls in elderly living at home

    Directory of Open Access Journals (Sweden)

    Adriana de Azevedo Smith

    Full Text Available ABSTRACT Objective: to assess the risk of falls in elderly, by comparing the sociodemographic and cognitive factors, history of falls and self-reported comorbidities. Method: cross-sectional and quantitative study with 240 elderly. Data were collected based on the social profile, through the instrument of risk of falls and assessment of falls, by univariate analysis, bivariate and multiple logistic regression. The Statistical Package for the Social Sciences (SPSS version 19 was used for statistical analysis. Results: there was a significant association of the risk of falls, as measured by the Fall Risk Score, with sex (<0.001, age (0.054, cognitive status (<0.001 and history of falls (<0.001. All variables were statistically significant and contributed to the occurrence of falls. In logistic regression, the variables that showed association with risk of falls were: fall, with whom they live, hypertension and visual impairment. Conclusion: female gender, older elderly (over 80 years old, with low cognitive status and occurrence of previous falls in the last six months are factors that increase the prevalence of falls. In logistic regression, the variables that were associated with risk of falls were: fall, with whom they live, visual impairment and rheumatologic diseases.

  6. Atmospheric Mercury Concentrations Near Salmon Falls Creek Reservoir - Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    M. L. Abbott

    2005-10-01

    Elemental and reactive gaseous mercury (EGM/RGM) were measured in ambient air concentrations over a two-week period in July/August 2005 near Salmon Falls Creek Reservoir, a popular fishery located 50 km southwest of Twin Falls, Idaho. A fish consumption advisory for mercury was posted at the reservoir in 2002 by the Idaho Department of Health and Welfare. The air measurements were part of a multi-media (water, sediment, precipitation, air) study initiated by the Idaho Department of Environmental Quality and the U.S. Environmental Protection Agency (EPA) Region 10 to identify potential sources of mercury contamination to the reservoir. The sampling site is located about 150 km northeast of large gold mining operations in Nevada, which are known to emit large amounts of mercury to the atmosphere (est. 2,200 kg/y from EPA 2003 Toxic Release Inventory). The work was co-funded by the Idaho National Laboratory’s Community Assistance Program and has a secondary objective to better understand mercury inputs to the environment near the INL, which lies approximately 230 km to the northeast. Sampling results showed that both EGM and RGM concentrations were significantly elevated (~ 30 – 70%, P<0.05) compared to known regional background concentrations. Elevated short-term RGM concentrations (the primary form that deposits) were likely due to atmospheric oxidation of high EGM concentrations, which suggests that EGM loading from upwind sources could increase Hg deposition in the area. Back-trajectory analyses indicated that elevated EGM and RGM occurred when air parcels came out of north-central and northeastern Nevada. One EGM peak occurred when the air parcels came out of northwestern Utah. Background concentrations occurred when the air was from upwind locations in Idaho (both northwest and northeast). Based on 2003 EPA Toxic Release Inventory data, it is likely that most of the observed peaks were from Nevada gold mine sources. Emissions from known large natural mercury

  7. Identifying nursing home residents at risk for falling.

    Science.gov (United States)

    Kiely, D K; Kiel, D P; Burrows, A B; Lipsitz, L A

    1998-05-01

    To develop a fall risk model that can be used to identify prospectively nursing home residents at risk for falling. The secondary objective was to determine whether the nursing home environment independently influenced the development of falls. A prospective study involving 1 year of follow-up. Two hundred seventy-two nursing homes in the state of Washington. A total of 18,855 residents who had a baseline assessment in 1991 and a follow-up assessment within the subsequent year. Baseline Minimum Data Set items that could be potential risk factors for falling were considered as independent variables. The dependent variable was whether the resident fell as reported at the follow-up assessment. We estimated the extrinsic risk attributable to particular nursing home environments by calculating the annual fall rate in each nursing home and grouping them into tertiles of fall risk according to these rates. Factors associated independently with falling were fall history, wandering behavior, use of a cane or walker, deterioration of activities of daily living performance, age greater than 87 years, unsteady gait, transfer independence, wheelchair independence, and male gender. Nursing home residents with a fall history were more than three times as likely to fall during the follow-up period than residents without a fall history. Residents in homes with the highest tertile of fall rates were more than twice as likely to fall compared with residents of homes in the lowest tertile, independent of resident-specific risk factors. Fall history was identified as the strongest risk factor associated with subsequent falls and accounted for the vast majority of the predictive strength of the model. We recommend that fall history be used as an initial screener for determining eligibility for fall intervention efforts. Studies are needed to determine the facility characteristics that contribute to fall risk, independent of resident-specific risk factors.

  8. Elderly fall risk prediction using static posturography

    Science.gov (United States)

    2017-01-01

    Maintaining and controlling postural balance is important for activities of daily living, with poor postural balance being predictive of future falls. This study investigated eyes open and eyes closed standing posturography with elderly adults to identify differences and determine appropriate outcome measure cut-off scores for prospective faller, single-faller, multi-faller, and non-faller classifications. 100 older adults (75.5 ± 6.7 years) stood quietly with eyes open and then eyes closed while Wii Balance Board data were collected. Range in anterior-posterior (AP) and medial-lateral (ML) center of pressure (CoP) motion; AP and ML CoP root mean square distance from mean (RMS); and AP, ML, and vector sum magnitude (VSM) CoP velocity were calculated. Romberg Quotients (RQ) were calculated for all parameters. Participants reported six-month fall history and six-month post-assessment fall occurrence. Groups were retrospective fallers (24), prospective all fallers (42), prospective fallers (22 single, 6 multiple), and prospective non-fallers (47). Non-faller RQ AP range and RQ AP RMS differed from prospective all fallers, fallers, and single fallers. Non-faller eyes closed AP velocity, eyes closed VSM velocity, RQ AP velocity, and RQ VSM velocity differed from multi-fallers. RQ calculations were particularly relevant for elderly fall risk assessments. Cut-off scores from Clinical Cut-off Score, ROC curves, and discriminant functions were clinically viable for multi-faller classification and provided better accuracy than single-faller classification. RQ AP range with cut-off score 1.64 could be used to screen for older people who may fall once. Prospective multi-faller classification with a discriminant function (-1.481 + 0.146 x Eyes Closed AP Velocity—0.114 x Eyes Closed Vector Sum Magnitude Velocity—2.027 x RQ AP Velocity + 2.877 x RQ Vector Sum Magnitude Velocity) and cut-off score 0.541 achieved an accuracy of 84.9% and is viable as a screening tool for older

  9. Elderly fall risk prediction using static posturography.

    Science.gov (United States)

    Howcroft, Jennifer; Lemaire, Edward D; Kofman, Jonathan; McIlroy, William E

    2017-01-01

    Maintaining and controlling postural balance is important for activities of daily living, with poor postural balance being predictive of future falls. This study investigated eyes open and eyes closed standing posturography with elderly adults to identify differences and determine appropriate outcome measure cut-off scores for prospective faller, single-faller, multi-faller, and non-faller classifications. 100 older adults (75.5 ± 6.7 years) stood quietly with eyes open and then eyes closed while Wii Balance Board data were collected. Range in anterior-posterior (AP) and medial-lateral (ML) center of pressure (CoP) motion; AP and ML CoP root mean square distance from mean (RMS); and AP, ML, and vector sum magnitude (VSM) CoP velocity were calculated. Romberg Quotients (RQ) were calculated for all parameters. Participants reported six-month fall history and six-month post-assessment fall occurrence. Groups were retrospective fallers (24), prospective all fallers (42), prospective fallers (22 single, 6 multiple), and prospective non-fallers (47). Non-faller RQ AP range and RQ AP RMS differed from prospective all fallers, fallers, and single fallers. Non-faller eyes closed AP velocity, eyes closed VSM velocity, RQ AP velocity, and RQ VSM velocity differed from multi-fallers. RQ calculations were particularly relevant for elderly fall risk assessments. Cut-off scores from Clinical Cut-off Score, ROC curves, and discriminant functions were clinically viable for multi-faller classification and provided better accuracy than single-faller classification. RQ AP range with cut-off score 1.64 could be used to screen for older people who may fall once. Prospective multi-faller classification with a discriminant function (-1.481 + 0.146 x Eyes Closed AP Velocity-0.114 x Eyes Closed Vector Sum Magnitude Velocity-2.027 x RQ AP Velocity + 2.877 x RQ Vector Sum Magnitude Velocity) and cut-off score 0.541 achieved an accuracy of 84.9% and is viable as a screening tool for older

  10. Elderly fall risk prediction using static posturography.

    Directory of Open Access Journals (Sweden)

    Jennifer Howcroft

    Full Text Available Maintaining and controlling postural balance is important for activities of daily living, with poor postural balance being predictive of future falls. This study investigated eyes open and eyes closed standing posturography with elderly adults to identify differences and determine appropriate outcome measure cut-off scores for prospective faller, single-faller, multi-faller, and non-faller classifications. 100 older adults (75.5 ± 6.7 years stood quietly with eyes open and then eyes closed while Wii Balance Board data were collected. Range in anterior-posterior (AP and medial-lateral (ML center of pressure (CoP motion; AP and ML CoP root mean square distance from mean (RMS; and AP, ML, and vector sum magnitude (VSM CoP velocity were calculated. Romberg Quotients (RQ were calculated for all parameters. Participants reported six-month fall history and six-month post-assessment fall occurrence. Groups were retrospective fallers (24, prospective all fallers (42, prospective fallers (22 single, 6 multiple, and prospective non-fallers (47. Non-faller RQ AP range and RQ AP RMS differed from prospective all fallers, fallers, and single fallers. Non-faller eyes closed AP velocity, eyes closed VSM velocity, RQ AP velocity, and RQ VSM velocity differed from multi-fallers. RQ calculations were particularly relevant for elderly fall risk assessments. Cut-off scores from Clinical Cut-off Score, ROC curves, and discriminant functions were clinically viable for multi-faller classification and provided better accuracy than single-faller classification. RQ AP range with cut-off score 1.64 could be used to screen for older people who may fall once. Prospective multi-faller classification with a discriminant function (-1.481 + 0.146 x Eyes Closed AP Velocity-0.114 x Eyes Closed Vector Sum Magnitude Velocity-2.027 x RQ AP Velocity + 2.877 x RQ Vector Sum Magnitude Velocity and cut-off score 0.541 achieved an accuracy of 84.9% and is viable as a screening tool for

  11. Rise and fall of the German nuclear industry; Aufstieg und Fall der deutschen Atomwirtschaft

    Energy Technology Data Exchange (ETDEWEB)

    Radkau, Joachim [Bielefeld Univ. (Germany). Neuere Geschichte; Hahn, Lothar

    2013-02-01

    The book on the rise and fall of the German nuclear industry includes five chapters: (1) From the atomic project of the second world war to the ''peaceful atom''. (2) The ''peaceful atom'' as vision: the phase of speculations. (3) Achieved facts: the unplanned triumph of the light water reactor. (4) The internally suppressed risk excites the public. (5) From the creeping to the open fall.

  12. Falls in ambulatory individuals with spinal cord injury : incidence, risk factors and perceptions of falls

    OpenAIRE

    Jørgensen, Vivien

    2016-01-01

    Background: Falls in ambulatory individuals with chronic spinal cord injury (SCI) are common and may have adverse consequences. Little and inconclusive research has been done in this population, and there is a need for more knowledge in order to develop prevention strategies appropriate for this population. Aim: The overall aim of this thesis was to study the incidence of and identify the risk factors for recurrent (>2) and injurious falls in ambulatory individuals with SCI...

  13. Urban acid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Conlan, D.E.; Longhurst, J.W.S.; Gee, D.R.; Hare, S.E.

    1991-07-01

    In this document results from the Greater Manchester Acid Deposition Survey (GMADS), an urban precipitation chemistry network, for 1990 are presented. Full analytical methods are described along with the precision and accuracy of the methods used. The spatial variability of precipitation chemistry and deposition over this urban region was investigated using a network of twenty collectors. Concentrations of non marine sulphate, ammonium, calcium and hydrogen, and nitrogen dioxide gas concentrations all show significant spatial variability. The spatial variability of the deposition rates of non marine sulphate, nitrate, ammonium, hydrogen and calcium were significant. (Author).

  14. Electroless atomic layer deposition

    Science.gov (United States)

    Robinson, David Bruce; Cappillino, Patrick J.; Sheridan, Leah B.; Stickney, John L.; Benson, David M.

    2017-10-31

    A method of electroless atomic layer deposition is described. The method electrolessly generates a layer of sacrificial material on a surface of a first material. The method adds doses of a solution of a second material to the substrate. The method performs a galvanic exchange reaction to oxidize away the layer of the sacrificial material and deposit a layer of the second material on the surface of the first material. The method can be repeated for a plurality of iterations in order to deposit a desired thickness of the second material on the surface of the first material.

  15. Falls and Use of Assistive Devices in Stroke Patients with Hemiparesis: Association with Balance Ability and Fall Efficacy.

    Science.gov (United States)

    Kim, Oksoo; Kim, Jung-Hee

    2015-01-01

    This study investigates balance ability and the fall efficacy with regard to the experiences of stroke patients with hemiparesis. The experience of falling, the use of assistive devices, and each disease-related characteristic were assessed using face-to-face interviews and a self-reported questionnaire. The Berg Balance Scale and Fall Efficacy Scale were used to measure balance ability and confidence. The fall efficacy was significantly lower in participants who had experienced falls than those who had not. The participants who used assistive devices exhibited low balance ability and fall efficacy compared to those who did not use assistive devices. Stroke patients with fall experience and walking aids might be considered at increased risk of falling. Preventive measures for individuals using walking aids may be beneficial in reducing the fall rate of community-dwelling stroke patients. © 2014 Association of Rehabilitation Nurses.

  16. The Association Between Body Adiposity Measures, Postural Balance, Fear of Falling, and Fall Risk in Older Community-Dwelling Women.

    Science.gov (United States)

    Neri, Silvia Gonçalves Ricci; Gadelha, André Bonadias; de David, Ana Cristina; Ferreira, Aparecido Pimentel; Safons, Marisete Peralta; Tiedemann, Anne; Lima, Ricardo M

    2017-12-07

    Recent investigations demonstrate an association between obesity and the propensity of older adults to fall. The aim of this study was to investigate the association between body adiposity measures, postural balance, fear of falling, and risk of falls in older women. One hundred forty-seven volunteers took part in this cross-sectional study. Participants underwent body composition assessment using dual-energy x-ray absorptiometry and had body mass index, waist circumference (WC), and body adiposity index measured. Postural balance was assessed using a force platform, while fear of falling and risk of falls were, respectively, evaluated by the Falls Efficacy Scale-International and the QuickScreen Clinical Falls Risk Assessment. All adiposity measures were correlated to at least 1 postural stability parameter and to fear of falling (ρ= 0.163, P risk of falls (ρ= 0.325; P falling (28.04 vs 24.59; P = .002) and had a higher proportion of individuals with increased fall risk (72% vs 35%; P risk of falls in older women, which might be mediated by reduced postural balance and increased fear of falling. Among these indices, WC, an easy and low-cost assessment, demonstrated the strongest association with falls-related outcomes.

  17. The grain size dependency of vesicular particle shapes strongly affects the drag of particles. First results from microtomography investigations of Campi Flegrei fallout deposits

    Science.gov (United States)

    Mele, Daniela; Dioguardi, Fabio

    2018-03-01

    Acknowledging the grain size dependency of shape is important in volcanology, in particular when dealing with tephra produced and emplaced during and after explosive volcanic eruptions. A systematic measurement of the tridimensional shape of vesicular pyroclasts of Campi Flegrei fallout deposits (Agnano-Monte Spina, Astroni 6 and Averno 2 eruptions) varying in size from 8.00 to 0.016 mm has been carried out by means of X-Ray Microtomography. Data show that particle shape changes with size, especially for juvenile vesicular clasts, since it is dependent on the distribution and size of vesicles that contour the external clast outline. Two drag laws that include sphericity in the formula were used for estimating the dependency of settling velocity on shape. Results demonstrate that it is not appropriate to assume a size-independent shape for vesicular particles, in contrast with the approach commonly employed when simulating the ash dispersion in the atmosphere.

  18. Cesium levels in foodstuffs fall slowly

    International Nuclear Information System (INIS)

    Rantavaara, A.

    1994-01-01

    Since spring 1986, radioactive decay has reduced the total amount of radioactive cesium 137 in the Finnish environment, originating in Chernobyl, by 17 per cent. The cesium content in fish keeps falling at a diminishing rate, depending on the species of fish and environmental factors. The use of fish from lakes need not be restricted anymore. The cesium contents of game, mushrooms and wild berries have remained steady for some years now. The same is true for agricultural produce. The contents in milk and meat still keep falling slowly. Most of the cesium ingested by finns comes from fish, then from game, reindeer and gathered foods; the lowest amounts are received from agricultural products. (orig.)

  19. FirstMile US Fall 2005 Conference

    Science.gov (United States)

    2005-12-01

    Moore, Virginia Tech 5. Broadband Delivery means Living Longer and Living Better a. The First Mile in Healthcare, Michael Ackerman, National Library of...deal with it and interact with it." The Internet will be delivered by a wide variety of means and go to places where people may not have access to...Fall 2005 Conference Proceedings First Regional Commnunity Network - OneCleveland Steven Brand, OneCleveland 4U -ýýeý L ECommunity Computing -Thin

  20. Geothermal Injection Monitoring in Klamath Falls, OR

    Energy Technology Data Exchange (ETDEWEB)

    Culver, G

    1990-01-01

    Klamath Falls has nearly a 150-year history of geothermal utilization. The geothermal aquifer has been the subject of many studies and is probably the most tested direct use reservoir in the world. This provides good background data for increased monitoring needed as new injection wells are drilled. Prior to July 1990, few injection wells existed. A city ordinance requires injection after July 1990. The city and major injectors have initiated a monitoring system.

  1. The 'Falling Box' method in general relativity

    International Nuclear Information System (INIS)

    Gladush, V.D.

    1998-01-01

    The problems of justification, generalization, and applicability of the 'falling box' method to obtained some exact solutions of the vacuum Einstein equations are investigated. The 'physical' inference of the Reissner-Nordstrom-de Sitter and Kerr metrics is shown. Explanation is given for the well-known relativistic phenomenon which consists in that gravity is created by the double density of the electrical field energy

  2. Effect of impact surface in equestrian falls

    OpenAIRE

    Clark, J. Michio; Post, Andrew; Connor, Thomas A.; Hoshizaki, Thomas Blaine; Gilchrist, M. D.

    2016-01-01

    This study examines the effect of impact surface on head kinematic response and maximum principal strain (MPS) for equestrian falls. A helmeted Hybrid III headform was dropped unrestrained onto three impact surfaces of different stiffness (steel, turf and sand) and three locations. Peak resultant linear acceleration, rotational acceleration and duration of the impact events were measured. A finite element brain model was used to calculate MPS. The results revealed that drops onto steel produc...

  3. An alternative model of free fall

    Science.gov (United States)

    Lattery, Mark

    2018-03-01

    In Two World Systems (Galileo 1632/1661 Dialogues Concerning Two New Sciences (New York: Prometheus)), Galileo attempted to unify terrestrial and celestial motions using the Aristotelian principle of circularity. The result was a model of free fall that correctly predicts the linear increase of the velocity of an object released from rest near the surface of the Earth. This historical episode provides an opportunity to communicate the nature of science to students.

  4. Airman Scholar Journal. Volume 17, Fall 2011

    Science.gov (United States)

    2011-01-01

    contends there must be a balance of the formal rea- soning of the social sciences and the informal reasoning of the humanities, which is one reason...USAFA’s founding, the “American Clausewitz,” Bernard Brodie ruminated : Economists …have a theoretical train- ing that in its fundamentals bears...kindled. - Plutarch 6 Airman Scholar • Fall 2011 16 Ibid., 5-1. Admiral Larson contended that concentrating like functions within

  5. Elderly fall risk prediction using static posturography

    OpenAIRE

    Howcroft, Jennifer; Lemaire, Edward D.; Kofman, Jonathan; McIlroy, William E.

    2017-01-01

    Maintaining and controlling postural balance is important for activities of daily living, with poor postural balance being predictive of future falls. This study investigated eyes open and eyes closed standing posturography with elderly adults to identify differences and determine appropriate outcome measure cut-off scores for prospective faller, single-faller, multi-faller, and non-faller classifications. 100 older adults (75.5 ± 6.7 years) stood quietly with eyes open and then eyes closed w...

  6. Modeling seasonal migration of fall armyworm moths

    Science.gov (United States)

    Westbrook, J. K.; Nagoshi, R. N.; Meagher, R. L.; Fleischer, S. J.; Jairam, S.

    2016-02-01

    Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a highly mobile insect pest of a wide range of host crops. However, this pest of tropical origin cannot survive extended periods of freezing temperature but must migrate northward each spring if it is to re-infest cropping areas in temperate regions. The northward limit of the winter-breeding region for North America extends to southern regions of Texas and Florida, but infestations are regularly reported as far north as Québec and Ontario provinces in Canada by the end of summer. Recent genetic analyses have characterized migratory pathways from these winter-breeding regions, but knowledge is lacking on the atmosphere's role in influencing the timing, distance, and direction of migratory flights. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to simulate migratory flight of fall armyworm moths from distinct winter-breeding source areas. Model simulations identified regions of dominant immigration from the Florida and Texas source areas and overlapping immigrant populations in the Alabama-Georgia and Pennsylvania-Mid-Atlantic regions. This simulated migratory pattern corroborates a previous migratory map based on the distribution of fall armyworm haplotype profiles. We found a significant regression between the simulated first week of moth immigration and first week of moth capture (for locations which captured ≥10 moths), which on average indicated that the model simulated first immigration 2 weeks before first captures in pheromone traps. The results contribute to knowledge of fall armyworm population ecology on a continental scale and will aid in the prediction and interpretation of inter-annual variability of insect migration patterns including those in response to climatic change and adoption rates of transgenic cultivars.

  7. Fear of Falling in Older Adults: Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Dukyoo Jung, PhD, RN

    2008-12-01

    Full Text Available Fear of falling has been reported in a high percentage of community-dwelling elderly who both do and don't have a history of falling. The aims of this review are to: (a elucidate the definition of fear of falling; (b clarify measurements of fear of falling based on its definition; and (c describe the risk factors for fear of falling. Despite the importance of the percentage and the consequences of fear of falling, its definition is still vague and warrants clarification. Based on a literature review, major fear of falling measurements involve the evaluation of fear of falling and use of a fall efficacy scale. Using a correct definition of fear of falling, nurses working close with older adults need to identify the different definitions of fear of falling and fall efficacy scale. In addition, nurses who work closely with older adults should encourage them to increase or maintain modifiable factors by maximizing their basic health status and enhancing their physical activity to decrease fear of falling.

  8. Falling through the black hole horizon

    International Nuclear Information System (INIS)

    Brustein, Ram; Medved, A.J.M.

    2015-01-01

    We consider the fate of a small classical object, a “stick”, as it falls through the horizon of a large black hole (BH). Classically, the equivalence principle dictates that the stick is affected by small tidal forces, and Hawking’s quantum-mechanical model of BH evaporation makes essentially the same prediction. If, on the other hand, the BH horizon is surrounded by a “firewall”, the stick will be consumed as it falls through. We have recently extended Hawking’s model by taking into account the quantum fluctuations of the geometry and the classical back-reaction of the emitted particles. Here, we calculate the strain exerted on the falling stick for our model. The strain depends on the near-horizon state of the Hawking pairs. We find that, after the Page time when the state of the pairs deviates significantly from maximal entanglement (as required by unitarity), the induced strain in our semiclassical model is still parametrically small. This is because the number of the disentangled pairs is parametrically smaller than the BH entropy. A firewall does, however, appear if the number of disentangled pairs near the horizon is of order of the BH entropy, as implicitly assumed in previous discussions in the literature.

  9. Relativistic theory of the falling retroreflector gravimeter

    Science.gov (United States)

    Ashby, Neil

    2018-02-01

    We develop a relativistic treatment of interference between light reflected from a falling cube retroreflector in the vertical arm of an interferometer, and light in a reference beam in the horizontal arm. Coordinates that are nearly Minkowskian, attached to the falling cube, are used to describe the propagation of light within the cube. Relativistic effects such as the dependence of the coordinate speed of light on gravitational potential, propagation of light along null geodesics, relativity of simultaneity, and Lorentz contraction of the moving cube, are accounted for. The calculation is carried to first order in the gradient of the acceleration of gravity. Analysis of data from a falling cube gravimeter shows that the propagation time of light within the cube itself causes a significant reduction in the value of the acceleration of gravity obtained from measurements, compared to assuming reflection occurs at the face. An expression for the correction to g is derived and found to agree with experiment. Depending on the instrument, the correction can be several microgals, comparable to commonly applied corrections such as those due to polar motion and earth tides. The controversial ‘speed of light’ correction is discussed. Work of the US government, not subject to copyright.

  10. Fall Down Detection Under Smart Home System.

    Science.gov (United States)

    Juang, Li-Hong; Wu, Ming-Ni

    2015-10-01

    Medical technology makes an inevitable trend for the elderly population, therefore the intelligent home care is an important direction for science and technology development, in particular, elderly in-home safety management issues become more and more important. In this research, a low of operation algorithm and using the triangular pattern rule are proposed, then can quickly detect fall-down movements of humanoid by the installation of a robot with camera vision at home that will be able to judge the fall-down movements of in-home elderly people in real time. In this paper, it will present a preliminary design and experimental results of fall-down movements from body posture that utilizes image pre-processing and three triangular-mass-central points to extract the characteristics. The result shows that the proposed method would adopt some characteristic value and the accuracy can reach up to 90 % for a single character posture. Furthermore the accuracy can be up to 100 % when a continuous-time sampling criterion and support vector machine (SVM) classifier are used.

  11. Hospitalisations due to falls in older persons.

    LENUS (Irish Health Repository)

    Carey, D

    2005-06-01

    This paper describes hospitalisations due to falls among people aged 65 years and over resident in the Eastern Region of Ireland. Of the 2,029 hospitalisations recorded for 2002, 78% were female and 68% were aged 75 years and over. Fractures accounted for 1,697 or 84% of cases with nearly half of them (841) sustained to the hip. Females were more likely to have a limb fracture whereas males were more likely to have a head injury. The total inpatient costs of the 2,029 hospitalisations were estimated at 10.6 million euros. Hip fractures were the costliest injuries as they accounted for 7.4 million euros (70%) of inpatient costs. There are also substantial additional costs implications for hip fractures as they constituted the majority (56%) of cases transferred to nursing\\/convalescent homes or long-stay health facilities. In keeping with an ageing population, the problem of injuries in older people is likely to increase over time and as falls are the dominant cause of those injuries, all acute and long-stay health facilities need to develop and implement fall prevention strategies for older people.

  12. Albeni Falls Wildlife Mitigation : Annual Report 2002.

    Energy Technology Data Exchange (ETDEWEB)

    Terra-Berns, Mary

    2003-01-01

    The Albeni Falls Interagency Work Group continued to actively engage in implementing wildlife mitigation actions in 2002. Regular Work Group meetings were held to discuss budget concerns affecting the Albeni Falls Wildlife Mitigation Program, to present potential acquisition projects, and to discuss and evaluate other issues affecting the Work Group and Project. Work Group members protected 1,386.29 acres of wildlife habitat in 2002. To date, the Albeni Falls project has protected approximately 5,914.31 acres of wildlife habitat. About 21% of the total wildlife habitat lost has been mitigated. Administrative activities have increased as more properties are purchased and continue to center on restoration, operation and maintenance, and monitoring. In 2001, Work Group members focused on development of a monitoring and evaluation program as well as completion of site-specific management plans. This year the Work Group began implementation of the monitoring and evaluation program performing population and plant surveys, data evaluation and storage, and map development as well as developing management plans. Assuming that the current BPA budget restrictions will be lifted in the near future, the Work Group expects to increase mitigation properties this coming year with several potential projects.

  13. Alluvial Deposits in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This coverage maps alluvial deposits throughout Iowa. This generally would include areas of alluvial soils associated with modern streams that are identified on...

  14. 75 FR 20041 - Deposits

    Science.gov (United States)

    2010-04-16

    ... transmission to (202) 906- 6518; or send an e-mail to [email protected] . OTS will post... DD implements the Truth in Savings Act, part of the Federal Deposit Insurance Corporation Improvement...

  15. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  16. Uranium deposit research, 1983

    International Nuclear Information System (INIS)

    Ruzicka, V.; LeCheminant, G.M.

    1984-01-01

    Research on uranium deposits in Canada, conducted as a prerequisite for assessment of the Estimated Additional Resources of uranium, revealed that (a) the uranium-gold association in rudites of the Huronian Supergroup preferably occurs in the carbon layers; (b) chloritized ore at the Panel mine, Elliot Lake, Ontario, occurs locally in tectonically disturbed areas in the vicinity of diabase dykes; (c) mineralization in the Black Sturgeon Lake area, Ontario, formed from solutions in structural and lithological traps; (d) the Cigar Lake deposit, Saskatchewan, has two phases of mineralization: monomineralic and polymetallic; (e) mineralization of the JEB (Canoxy Ltd.) deposit is similar to that at McClean Lake; (f) the uranium-carbon assemblage was identified in the Claude deposit, Carswell Structure; and (g) the Otish Mountains area, Quebec, should be considered as a significant uranium-polymetallic metallogenic province

  17. Automatic Payroll Deposit System.

    Science.gov (United States)

    Davidson, D. B.

    1979-01-01

    The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)

  18. Deposition of acidifying compounds

    International Nuclear Information System (INIS)

    Fowler, D.; Cape, J.N.; Sutton, M.A.; Mourne, R.; Hargreaves, K.J.; Duyzer, J.H.; Gallagher, M.W.

    1992-01-01

    Inputs of acidifying compounds to terrestrial ecosystems include deposition of the gases NO 2 , NO, HNO 2 , HNO 3 , NH 3 and SO 2 and the ions NO 3- , NH 4+ , SO 4 2- and H + in precipitation, cloud droplets and particles. Recent research has identified particular ecosystems and regions in which terrestrial effects are closely linked with specific deposition processes. This review paper identifies areas in which important developments have occurred during the last five years and attempts to show which aspects of the subject are most important for policy makers. Amongst the conclusions drawn, the authors advise that current uncertainties in estimates of S and N inputs by dry deposition should be incorporated in critical load calculations, and that, in regions dominated by wet deposition, spatial resolution of total inputs should be improved to match the current scales of information on landscape sensitivity to acidic inputs. 44 refs., 9 figs

  19. Speleothem (Cave Deposit) Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, and other aspects of climate derived from mineral deposits found in caves. Parameter keywords describe what was measured...

  20. Clinical and Community Strategies to Prevent Falls and Fall-Related Injuries Among Community-Dwelling Older Adults.

    Science.gov (United States)

    Taylor-Piliae, Ruth E; Peterson, Rachel; Mohler, Martha Jane

    2017-09-01

    Falls in older adults are the result of several risk factors across biological and behavioral aspects of the person, along with environmental factors. Falls can trigger a downward spiral in activities of daily living, independence, and overall health outcomes. Clinicians who care for older adults should screen them annually for falls. A multifactorial comprehensive clinical fall assessment coupled with tailored interventions can result in a dramatic public health impact, while improving older adult quality of life. For community-dwelling older adults, effective fall prevention has the potential to reduce serious fall-related injuries, emergency room visits, hospitalizations, institutionalization, and functional decline. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Atmospheric transport, diffusion, and deposition of radioactivity

    International Nuclear Information System (INIS)

    Crawford, T.V.

    1969-01-01

    From a meteorological standpoint there are two types of initial sources for atmospheric diffusion from Plowshare applications. One is the continuous point-source plume - a slow, small leak from an underground engineering application. The other is the large cloud produced almost instantaneously from a cratering application. For the purposes of this paper the effluent from neither type has significant fall speed. Both are carried by the prevailing wind, but the statistics of diffusion for each type are different. The use of constant altitude, isobaric and isentropic techniques for predicting the mean path of the effluent is briefly discussed. Limited data are used to assess the accuracy of current trajectory forecast techniques. Diffusion of continuous point-source plumes has been widely studied; only a brief review is given of the technique used and the variability of their results with wind speed and atmospheric stability. A numerical model is presented for computing the diffusion of the 'instantaneously-produced' large clouds. This model accounts for vertical and diurnal changes in atmospheric turbulence, wet and dry deposition, and radioactivity decay. Airborne concentrations, cloud size, and deposition on the ground are calculated. Pre- and post-shot calculations of cloud center, ground level concentration of gross radioactivity, and dry and wet deposition of iodine-131 are compared with measurements on Cabriolet and Buggy. (author)

  2. Atmospheric transport, diffusion, and deposition of radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, T V [Lawrence Radiation Laboratory, Livermore, CA (United States)

    1969-07-01

    From a meteorological standpoint there are two types of initial sources for atmospheric diffusion from Plowshare applications. One is the continuous point-source plume - a slow, small leak from an underground engineering application. The other is the large cloud produced almost instantaneously from a cratering application. For the purposes of this paper the effluent from neither type has significant fall speed. Both are carried by the prevailing wind, but the statistics of diffusion for each type are different. The use of constant altitude, isobaric and isentropic techniques for predicting the mean path of the effluent is briefly discussed. Limited data are used to assess the accuracy of current trajectory forecast techniques. Diffusion of continuous point-source plumes has been widely studied; only a brief review is given of the technique used and the variability of their results with wind speed and atmospheric stability. A numerical model is presented for computing the diffusion of the 'instantaneously-produced' large clouds. This model accounts for vertical and diurnal changes in atmospheric turbulence, wet and dry deposition, and radioactivity decay. Airborne concentrations, cloud size, and deposition on the ground are calculated. Pre- and post-shot calculations of cloud center, ground level concentration of gross radioactivity, and dry and wet deposition of iodine-131 are compared with measurements on Cabriolet and Buggy. (author)

  3. Gemstone deposits of Serbia

    Directory of Open Access Journals (Sweden)

    Miladinović Zoran

    2016-06-01

    Full Text Available Gemstone minerals in Serbia have never been regarded as an interesting and significant resource. Nevertheless, more than 150 deposits and occurrences have been recorded and some of them preliminarily explored in the last 50 years. The majority of deposits and occurrences are located within the Serbo-Macedonian metallogenic province and the most significant metallogenic units at the existing level of knowledge are the Fruska Gora ore district, Cer ore district, Sumadija metallogenic zone, Kopaonik metallogenic zone and Lece-Halkidiki metallogenic zone. The most important genetic type of deposits is hydrothermal, particularly in case of serpentinite/peridotite as host/parent rock. Placer deposits are also economically important. The dominant gemstones are silica minerals: chalcedony (Chrysoprase, carnelian, bluish chalcedony etc., jasper (picture, landscape, red etc., common opal (dendritic, green, milky white etc., silica masses (undivided, and quartz (rock crystal, amethyst etc.. Beside silica minerals significant gemstones in Serbia include also beryl (aquamarine, garnet (almandine and pyrope, tourmaline, fluorite, rhodochrosite, carbonate-silica breccia, carbonate-silica onyx, silicified wood, howlite, serpentinite, marble onyx, and kyanite. This paper aims to present an overview of Serbian gemstone deposits and occurrences and their position based on a simplified gemstone metallogenic map of Serbia, as well as genetic-industrial classification of gemstone deposits and gemstone varieties.

  4. Uranium deposits in Africa

    International Nuclear Information System (INIS)

    Wilpolt, R.H.; Simov, S.D.

    1979-01-01

    Africa is not only known for its spectacular diamond, gold, copper, chromium, platinum and phosphorus deposits but also for its uranium deposits. At least two uranium provinces can be distinguished - the southern, with the equatorial sub-province; and the south Saharan province. Uranium deposits are distributed either in cratons or in mobile belts, the first of sandstone and quartz-pebble conglomerate type, while those located in mobile belts are predominantly of vein and similar (disseminated) type. Uranium deposits occur within Precambrian rocks or in younger platform sediments, but close to the exposed Precambrian basement. The Proterozoic host rocks consist of sediments, metamorphics or granitoids. In contrast to Phanerozoic continental uranium-bearing sediments, those in the Precambrian are in marginal marine facies but they do contain organic material. The geology of Africa is briefly reviewed with the emphasis on those features which might control the distribution of uranium. The evolution of the African Platform is considered as a progressive reduction of its craton area which has been affected by three major Precambrian tectonic events. A short survey on the geology of known uranium deposits is made. However, some deposits and occurrences for which little published material is available are treated in more detail. (author)

  5. Gemstone deposits of Serbia

    Science.gov (United States)

    Miladinović, Zoran; Simić, Vladimir; Jelenković, Rade; Ilić, Miloje

    2016-06-01

    Gemstone minerals in Serbia have never been regarded as an interesting and significant resource. Nevertheless, more than 150 deposits and occurrences have been recorded and some of them preliminarily explored in the last 50 years. The majority of deposits and occurrences are located within the Serbo-Macedonian metallogenic province and the most significant metallogenic units at the existing level of knowledge are the Fruska Gora ore district, Cer ore district, Sumadija metallogenic zone, Kopaonik metallogenic zone and Lece-Halkidiki metallogenic zone. The most important genetic type of deposits is hydrothermal, particularly in case of serpentinite/peridotite as host/parent rock. Placer deposits are also economically important. The dominant gemstones are silica minerals: chalcedony (Chrysoprase, carnelian, bluish chalcedony etc.), jasper (picture, landscape, red etc.), common opal (dendritic, green, milky white etc.), silica masses (undivided), and quartz (rock crystal, amethyst etc.). Beside silica minerals significant gemstones in Serbia include also beryl (aquamarine), garnet (almandine and pyrope), tourmaline, fluorite, rhodochrosite, carbonate-silica breccia, carbonate-silica onyx, silicified wood, howlite, serpentinite, marble onyx, and kyanite. This paper aims to present an overview of Serbian gemstone deposits and occurrences and their position based on a simplified gemstone metallogenic map of Serbia, as well as genetic-industrial classification of gemstone deposits and gemstone varieties.

  6. Hematite Spherules in Basaltic Tephra Altered Under Aqueous, Acid-Sulfate Conditions on Mauna Kea Volcano, Hawaii: Possible Clues for the Occurrence of Hematite-Rich Spherules in the Burns Formation at Meridiani Planum, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Graff, T. G.; Arvidson, R. E.; Bell, J. F., III; Squyres, S. W.; Mertzman, S. A.; Gruener, J. E.; Golden, D. C.; Robinson, G. A.

    2005-01-01

    Iron-rich spherules (>90% Fe2O3 from electron microprobe analyses) approx.10-100 microns in diameter are found within sulfate-rich rocks formed by aqueous, acid-sulfate alteration of basaltic tephra on Mauna Kea volcano, Hawaii. Although some spherules are nearly pure Fe, most have two concentric compositional zones, with the core having a higher Fe/Al ratio than the rim. Oxide totals less than 100% (93-99%) suggest structural H2O and/or /OH. The transmission Moessbauer spectrum of a spherule-rich separate is dominated by a hematite (alpha-Fe2O3) sextet whose peaks are skewed toward zero velocity. Skewing is consistent with Al(3+) for Fe(3+) substitution and structural H2O and/or /OH. The grey color of the spherules implies specular hematite. Whole-rock powder X-ray diffraction spectra are dominated by peaks from smectite and the hydroxy sulfate mineral natroalunite as alteration products and plagioclase feldspar that was present in the precursor basaltic tephra. Whether spherule formation proceeded directly from basaltic material in one event (dissolution of basaltic material and precipitation of hematite spherules) or whether spherule formation required more than one event (formation of Fe-bearing sulfate rock and subsequent hydrolysis to hematite) is not currently constrained. By analogy, a formation pathway for the hematite spherules in sulfate-rich outcrops at Meridiani Planum on Mars (the Burns formation) is aqueous alteration of basaltic precursor material under acid-sulfate conditions. Although hydrothermal conditions are present on Mauna Kea, such conditions may not be required for spherule formation on Mars if the time interval for hydrolysis at lower temperatures is sufficiently long.

  7. Fear of falling and gait parameters in older adults with and without fall history.

    Science.gov (United States)

    Makino, Keitaro; Makizako, Hyuma; Doi, Takehiko; Tsutsumimoto, Kota; Hotta, Ryo; Nakakubo, Sho; Suzuki, Takao; Shimada, Hiroyuki

    2017-12-01

    Fear of falling (FOF) is associated with spatial and temporal gait parameters in older adults. FOF is prevalent among older adults, both those with and without fall history. It is still unclear whether the relationships between FOF and gait parameters are affected by fall history. The aim of the present study was to compare gait parameters by the presence of FOF and fall history. A total of 3575 older adults (mean age 71.7 years, 49.7% female) met the inclusion criteria for the present study. We assessed the presence of fall history and FOF by face-to-face interview, and gait parameters (gait speed, stride length, step rate, double support time and variation of stride length) at a comfortable speed using a computerized electronic walkway. Prevalences of fall history and FOF were as follows: non-fallers without FOF 52.6% (n = 1881); fallers without FOF 6.3% (n = 227); non-fallers with FOF 34.4% (n = 1229); and fallers with FOF 6.7% (n = 238). Analysis of covariance showed significant differences among the four groups in all gait variables even after adjusting for age, sex and number of medications used. It should be noted that non-fallers with FOF showed significantly slower gait speed, shorter stride length and longer double support time than did non-fallers without FOF (P fall history. The assessment of FOF might be helpful for better understanding of age-related changes in gait control. Geriatr Gerontol Int 2017; 17: 2455-2459. © 2017 Japan Geriatrics Society.

  8. Fall Risk Index predicts functional decline regardless of fall experiences among community-dwelling elderly.

    Science.gov (United States)

    Ishimoto, Yasuko; Wada, Taizo; Kasahara, Yoriko; Kimura, Yumi; Fukutomi, Eriko; Chen, Wenling; Hirosaki, Mayumi; Nakatsuka, Masahiro; Fujisawa, Michiko; Sakamoto, Ryota; Ishine, Masayuki; Okumiya, Kiyohito; Otsuka, Kuniaki; Matsubayashi, Kozo

    2012-10-01

    The 21-item Fall Risk Index (FRI-21) has been used to detect elderly persons at risk for falls. The aim of this longitudinal study was to evaluate the FRI-21 as a predictor of decline in basic activities of daily living (BADL) among Japanese community-dwelling elderly persons independent of fall risk. The study population consisted of 518 elderly participants aged 65 years and older who were BADL independent at baseline in Tosa, Japan. We examined risk factors for BADL decline from 2008 to 2009 by multiple logistic regression analysis on the FRI-21 and other functional status measures in all participants. We carried out the same analysis in selected participants who had no experience of falls to remove the effect of falls. A total of 45 of 518 participants showed decline in BADL within 1 year. Multivariate logistic regression analysis showed that age (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.05-1.20), FRI-21 ≥ 10 (OR 3.81, 95% CI 1.49-9.27), intellectual activity dependence (OR 3.25, 95% CI 1.42-7.44) and history of osteoarthropathy (OR 3.17, 95% CI 1.40-7.21) were significant independent risk factors for BADL decline within 1 year. FRI-21 ≥ 10 and intellectual activity dependence (≤ 3) remained significant predictors, even in selected non-fallers. FRI-21 ≥ 10 and intellectual activity dependence were significant predictive factors of BADL decline, regardless of fall experience, after adjustment for confounding variables. The FRI-21 is a brief, useful tool not only for predicting falls, but also future decline in functional ability in community-dwelling elderly persons. © 2012 Japan Geriatrics Society.

  9. Primary Care Fall Risk Assessment for Elderly West Virginians.

    Science.gov (United States)

    Minkemeyer, Vivian M; Meriweather, Matt; Shuler, Franklin D; Mehta, Saurabh P; Qazi, Zain N

    2015-01-01

    West Virginia is ranked second nationally for the percent of its population 65 years of age. The elderly are especially susceptible to falls with fall risk increasing as age increases. Because falls are the number one cause of injury-related morbidity and mortality in the West Virginia elderly, evaluation of fall risk is a critical component of the patient evaluation in the primary care setting. We therefore highlight fall risk assessments that require no specialized equipment or training and can easily be completed at an established office visit. High quality clinical practice guidelines supported by the American Geriatric Society recommend yearly fall risk evaluation in the elderly. Those seniors at greatest risk of falls will benefit from the standardized therapy protocols outlined and referral to a balance treatment center. Patients with low-to-moderate fall risk attributed to muscle weakness or fatigue should be prescribed lower extremity strengthening exercises, such as kitchen counter exercises, to improve strength and balance.

  10. P270: Factors associated with fall rate in psychogeriatric residents

    NARCIS (Netherlands)

    Kosse, N.M.; de Groot, Maartje H; Hortobágyi, T.; Lamoth, C.J.C.

    2014-01-01

    Introduction: Falls in psychogeriatric residents represent a costly but unresolved safety issue. Identifying fall risk factors and their inter-relationship may help to individualize prevention programs and increase the effectiveness. Therefore, we aimed to examine the relationship between patient

  11. Falls among pregnant women in Enugu, Southeast Nigeria

    African Journals Online (AJOL)

    2013-10-04

    Oct 4, 2013 ... Key words: Enugu, falls, Nigeria, pregnant women, prevalence, risk factors .... in which someone is paid some wages (salary) at specific intervals, for example .... initiated the process of filling the existing gap on falls during.

  12. Optimising a fall out dust monitoring sampling programme at a ...

    African Journals Online (AJOL)

    GREG

    Key words: Fall out dust monitoring, cement plant, optimising, air pollution sampling, fall out dust sampler locations. .... applied for those areas where controls are in place. Sampling ..... mass balance in the total cement manufacturing process.

  13. Fall with and without fracture in elderly: what's different?

    Science.gov (United States)

    Kantayaporn, Choochat

    2012-10-01

    Falling fracture was one of the health problems in elderly. This presentation aimed to identify the factors of fall that caused fractures. The retrospective case-control study was designed. Samples were all who experienced fall within 1 year in Lamphun. Factors included age, gender underlying diseases, chronic drugs used, history of parent fragility fracture, age of menopause, steroid used, body mass index, visual acuity and time up and go test were studied. Multivariate regression analysis was used. 336 cases of fractures in 1,244 cases of fall were found. Significant factors of falling fracture group that were differen