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Sample records for proxy tex86 show

  1. Distribution of lacustrine Crenarchaeota in Lake Superior: implications for the application of the TEX86 temperature proxy

    Science.gov (United States)

    Woltering, M. L.; Werne, J. P.; Hicks, R.; Kish, J.; Oster, R.; Schouten, S.; Sinninghe Damsté, J. S.

    2009-12-01

    The TEX86 is a proxy that can be applied on continental lake sediments to reconstruct past water temperatures. It is based on the lipids derived from aquatic Crenarchaeota, and although first applied in marine systems has already been successfully used in sediments from some of the continental lake drilling projects in Lake Malawi and Tanganyika. Recent studies have shown that the application of this proxy in lacustrine systems appears to be limited to mainly large to intermediate size lakes that are only marginally terrestrially influenced. Here TEX86 values from surface sediments appear to correlate strongly with both annual mean as mean winter surface water temperatures. Besides this observed empirical relationship between TEX86 values and lake surface temperatures, very little is known about the distribution and ecology of the organisms that produce the lipids that make up the TEX86 in lacustrine systems. Here we will present the results of our multiyear water column and sediment trap study in Lake Superior where we investigated where vertically and at what time of year the lipids are produced that make up the TEX86 proxy, which end up in the sediment record. We have combined both biogeochemical and molecular techniques to both water filter samples as sediment trap material, combined thermistor observations in the water column to create vertical profiles of Crenarchaeotal and lipid abundance to investigate the spatial distribution of the lacustrine Crenarchaeota in order to determine if or what kind of temperature is actually represented by the TEX86 proxy in Lake Superior. Our results show that the TEX86 measured in particulate organic matter does a good job reconstructing the actual thermal structure of the water column. However, the lipids that make up the TEX86 in Lake Superior are produced throughout the lake during isothermal conditions, but mainly below the thermocline when the lake is stratified suggesting that in Lake Superior the TEX86 largely

  2. Ecology of lacustrine Crenarchaeota in Lake Superior: Implications for the application of the TEX86 temperature proxy

    Science.gov (United States)

    Woltering, M.; Werne, J.; Hicks, R.; Kish, J.; Schouten, S.; Sinninghe Damsté, J.

    2008-12-01

    The TEX86 paleotemperature proxy, based on tetraether membrane lipids derived from aquatic Crenarchaeota has been applied in a variety of marine and lacustrine systems. A recent study analyzing a suite of 50 globally distributed lakes for TEX86 discovered that this proxy does not appear to work in all lake systems and that the TEX86 correlates well with both annual and winter lake surface water temperature in those systems where it does appear to work. Besides this observed empirical relationship between TEX86 values and lake surface temperatures, very little is known about the ecology of the crenarchaeota in lakes. We combined both biogeochemical and molecular techniques in a multiyear study of Lake Superior using both sediment trap collection of settling particulate matter over the annual cycle and filtration of suspended particulate matter from lake water to create vertical profiles of crenarchaeotal cell numbers and lipid concentrations to investigate the spatial and temporal ecology of the lacustrine Crenarchaeota. Initial results show that the flux of the tetraether lipids is highly seasonal and mainly occurs during two time periods in winter and spring. The flux-weighted TEX86-derived temperatures from the sediment trap material agrees with the TEX86 temperature from a sediment core top from the sampling site and mixed water temperatures during the two periods of highest flux within the error of the method. Spatially, lipids used in TEX86 are found throughout the water column when the Lake Superior is isothermal, but mainly in the hypolimnion when the lake is stratified. During stratification tetraether lipids in the eplimnion appear to reflect a surface water temperature, while the more abundant tetraether lipids in the hypolimnion reflect a deep water temperature. These data suggest that the TEX86 in sediments of Lake Superior mainly reflect the water temperatures of times of highest lipid flux, mixed with a smaller portion of lipids that are mainly

  3. Environmental and Physiological Influences on the TEX86 Proxy: Results from Continuous Culture Studies and Stable Carbon Isotope Analyses

    Science.gov (United States)

    Pearson, A.; Hurley, S.; Elling, F. J.; Koenneke, M.; Santoro, A. E.; Buchwald, C.; Wankel, S. D.; Hinrichs, K. U.; Zhang, Y.; Shah Walter, S. R.

    2015-12-01

    Membrane lipids of marine Archaea - known as GDGTs - are the basis of the TEX86 sea surface temperature (SST) paleoproxy. GDGTs are ubiquitous in marine sediments, and their broad distribution and high preservation potential have led to an ever-increasing use of TEX86. The planktonic Thaumarchaeota that are believed to be the major sources of GDGTs to marine sediments are autotrophic nitrifiers, assimilating carbon directly from dissolved CO2. Therefore the δ13C values of GDGTs additionally provide information about the DIC system and paleoproductivity. However, as for all biological proxies, understanding the physiology and biochemistry of the responsible organisms is essential to understanding how the proxies work. From this perspective, the TEX86-SST proxy is uniquely perplexing: How is it possible that multiple approaches to calibration show a good correlation between TEX86 and SSTs, when maximum activity of Thaumarchaeota is near and below the base of the photic zone? Here we show data from two studies that help address this question. Analyses of GDGT δ13C values show that the dominant GDGT flux to sediments is not from the sea surface. The data are measured on intact GDGTs purified by orthogonal dimensions of HPLC, followed by measurement of δ13C values on a Spooling Wire Microcombustion (SWiM)-IRMS with 1σ precision of ±0.2‰ and accuracy of ±0.3‰. Using this approach, we confirm that GDGTs, generally around -19.0‰ to -18.5‰, are isotopically "heavy" compared to other marine lipids, and that crenarchaeol in particular is a good tracer of water column GDGT export. In parallel, we investigated the mechanistic underpinning of the TEX86 proxy using isothermal culture studies of the ammonia-oxidizing thaumarchaeon Nitrosopumilus maritimus SCM1 to explore the relationship between TEX86 and growth conditions. Evidence suggests that growth rate and electron donor supply are important controls on GDGT ratios and that TEX86 scales with the in-situ rate of

  4. Spatial and temporal variability of Crenarchaeota in Lake Superior and implications for the application of the TEX86 temperature proxy

    Science.gov (United States)

    Woltering, M. L.; Werne, J. P.; Hicks, R. E.; Kish, J. L.; Schouten, S.; Sinninghe Damste, J. S.

    2010-12-01

    We present results of a study of Crenarchaeota in the water column of Lake Superior, in which their vertical distribution was examined through in situ filtration of suspended particulate matter (SPM) and temporal variability through a three-year time-series sediment trap deployment. We observed that Crenarchaeotal cells and membrane lipids are distributed throughout the water column during overturning conditions, but mainly reside in the hypolimnion when Lake Superior is thermally stratified. TEX86 derived temperatures in suspended particulate matter were in very good agreement with the actual water temperatures at times and depths that the SPM was sampled. Fluxes of isoprenoid crenarchaeotal membrane lipids towards the sediment mainly occur in winter and late spring/early summer and starts when the lake is overturning. We observed a strong covariance of all the fluxes analyzed in the sediment traps suggesting a role of resuspension and sediment focusing to the study site. A lack of seasonality in the trend of TEX86 derived temperatures in settling particles shows that the crenarchaeotal membrane lipid flux during the stratified period is likely dominated by lipids that have been produced in the hypolimnion. Both TEX86 derived temperatures from surface sediments and the flux weighted averaged temperatures from the sediment traps yield temperatures that are close the average hypolmnetic water temperature as well as the temperature observed during the start of overturning. These data suggest that the TEX86 from the sediments of Lake Superior largely reflects a subsurface water temperature and not an annual mean surface water temperature. The sensitivity of hypolimnetic water temperatures of Lake Superior to changes in atmospheric temperatures surrounding Lake Superior are small, even when large changes in atmospheric temperatures would occur over a century time scale. Therefore caution needs to be applied when interpreting trends of TEX86 temperatures from Lake

  5. Distributions of Core- and Polar- Archaeal Lipids in the Lower Pearl River and Estuary: Implications for TEX86 Proxies

    Science.gov (United States)

    Wang, J.; Zhang, C.; Zhu, C.; Wei, Y.; Dong, H.; Liu, W.

    2011-12-01

    Core isoprenoidal glycerol dibiphytanyl dlycerol tetraethers (C-iGDGTs) are the most widespread archaeal lipids in sediments and water, and have been used to construct a molecular proxy, TEX86, for studying past sea surface temperatures. However, recent analyses of intact polar (IP)-iGDGTs that are indicative of living archaea suggest that IP-iGDGTs produced in situ in marine sediments may subsequently convert IP-iGDGTs to C-iGDGTs after the cell death, thus compromising the validity of TEX86 for paleoclimate research. To help address this question, we investigated the distribution and abundance of IP- and C- iGDGTs in suspended particulates and surface sediments from the lower Pearl River and estuary. Our results show a strong positive correlation between the C- and P-iGDGTs pools, especially the iGDGT-0 (R2 = 0.786, pCrenarchaeota.

  6. Understanding controls on organic (Uk’37 and TEX86) and inorganic (Mg/Ca) SST proxies: insights from a long term Mozambique Channel sediment trap study

    Science.gov (United States)

    Castañeda, I. S.; Fallet, U.; Brummer, G. A.; Sinninghe Damsté, J. S.; Schouten, S.

    2009-12-01

    In 2003, an array of moorings equipped with instruments to measure temperature, salinity and water mass transport was placed across the Mozambique Channel as part of the Long-term Ocean Currents Observation (LOCO) Project. In addition, a sediment trap in the deep channel at 2011 m collected material at 21 day intervals from November 2003 until the present. These sediment trap samples, in combination with in situ and satellite-derived SST measurements, provide a unique opportunity to examine and directly compare organic and inorganic SST proxies. In this study we measured two organic SST proxies, the Uk’37 Index, which is based on the ratio of long-chain di- and triunsaturated ketones produced by haptophyte algae, and the more recently developed TEX86 proxy, which is based on glycerol dialkyl glycerol tetraethers (GDGTs) produced by Marine Group 1 Crenarchaeota. We also analyzed Mg/Ca ratios from two species of surface-dwelling foraminifera, G. ruber and G. trilobus, which provide an inorganic SST proxy. The results obtained up to now show that TEX86-based SST reconstructions capture the mean annual temperature of the study location accurately (mean annual SST is 28.1°C and TEX86 mean annual SST is 28.3°C); however, seasonal variability is not reflected by the TEX86 measurements. In contrast, the Mg/Ca records of G. ruber and G. trilobus, capture the seasonal variability in SST but display a slight offset relative to each other, with G. ruber typically 2 to 3°C warmer than G. trilobus. The Uk’37 Index was nearly always near unity due to the absence of the C37:3 alkenone, showing that this proxy is unable to capture SST at this tropical location. The differences between the organic and inorganic proxies might be due to the different sinking rates and lateral transport effects. To further investigate controls on the TEX86 proxy, we are currently examining intact polar lipids (IPLs) of GDGTs from the most recent year of sediment trap material. IPLs are more

  7. Distribution of tetraether lipids in surface sediments of the northern South China Sea: Implications for TEX86 proxies

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    Huangmin Ge

    2013-03-01

    Full Text Available Archaea have unique glycerol dialkyl glycerol tetraether (GDGT lipids that can be used to develop paleotemperature proxies such as TEX86. This research is to validate proposed GDGT-proxies for paleotemperature determination in the South China Sea (SCS. Samples were collected from core-top sediments (0–5 cm in the northern SCS. Total lipids were extracted to obtain core GDGTs, which were identified and quantified using liquid chromatography-mass spectrometry (LC-MS. The abundance of isoprenoidal GDGTs (iGDGTs ranged from 271.5 ng/g dry sediment to 1266.3 ng/g dry sediment, whereas the branched GDGTs (bGDGTs, supposedly derived from terrestrial sources, ranged from 22.2 ng/g dry sediment to 56.7 ng/g dry sediment. The TEX86-derived sea surface temperatures ranged from 20.9 °C in the coast (water depth  1000 m. TEX86-derived temperatures near shore (<160 m water depth averaged 23.1 ± 2.5 °C (n = 4, which were close to the satellite-derived winter mean sea surface temperature (average 22.6 ± 1.0 °C, n = 4; whereas the TEX86-derived temperatures offshore averaged 27.4 ± 0.3 °C (n = 7 and were consistent with the satellite mean annual sea surface temperature (average 26.8 ± 0.4 °C, n = 7. These results suggest that TEX86 may record the sea surface mean annual temperature in the open ocean, while it likely records winter sea surface temperature in the shallower water.

  8. Late Oligocene decoupling of temperature and pCO2: Insights from TEX86 paleothermometry

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    O'Brien, C. L.; Pagani, M.

    2016-12-01

    Current paleo-proxy reconstructions for the late Oligocene ( 28-23 Ma) indicate a decoupling of temperature and pCO2. Specifically, benthic oxygen isotope data suggest either stable conditions or warming/deglaciation, while alkenone-based pCO2 estimates indicate a decline from 700 to 400 ppm. Existing sea surface temperature (SST) proxy estimates for this interval are sparse and the appearance of decoupling could be fallacious. Using late Oligocene marine sediments from a range of oceanographic and latitudinal settings, in particular Atlantic Ocean sites ODP 929A (5°N), DSDP 608 (42°N) and DSDP 516F (30°S), we are applying the TEX86 paleothermometer to provide improved constraints on late Oligocene warmth. Thought to originate mainly from planktonic, ammonia-oxidizing Thaumarchaeota, the sedimentary TEX86 signal is complicated by potential influences from additional sources and non-thermal effects (e.g., water chemistry, nutrient dynamics, growth stage and ecology). Thus, we are simultaneously testing assumptions regarding the fidelity of the TEX86 paleo-SST proxy. Our new TEX86H-SST data from Atlantic site ODP 929A indicate stable SSTs in the tropics (often reflective of global conditions) during the late Oligocene, with no reduction in SST coincident with declining pCO2 during the period 28-24 Ma. Importantly, TEX86H-SST data show a lack of coherence with latitude exemplified by similar stable SSTs, 28°C, at tropical and southern mid-latitude Atlantic sites ODP 929 and DSDP 516F, respectively. This absence of a decrease in SST with increasing site latitude suggests that additional non-thermal factors may be influencing the TEX86 signal at certain locations and/or a need for regional-based TEX86-SST calibrations. Indeed, if our tropical TEX86-SST reconstructions ( 28°C) are valid then this would imply the late Oligocene tropical Atlantic was no warmer than the Pliocene, contradicting multiple lines of evidence that the world was warmer (e.g., higher pCO2

  9. Coherent millennial-scale patterns in U37k‧ and TEX86H temperature records during the penultimate interglacial-to-glacial cycle in the western Mediterranean

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    Huguet, Carme; Martrat, Belen; Grimalt, Joan O.; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2011-06-01

    The TEX86H temperature proxy is a relatively new proxy based on crenarchaeotal lipids and has rarely been applied together with other temperature proxies. In this study, we applied the TEX86H on a sediment core from the Alboran Sea (western Mediterranean, core ODP-977A) covering the penultimate climate cycle, that is, from 244 to 130 ka, and compared this with previously published sea surface temperatures derived from the U37k' of alkenones of haptophyta and Mg/Ca records of planktonic foraminifera. The TEX86H temperature record shows remarkably similar stadial-interstadial patterns and abrupt temperature changes to those observed with the U37k' palaeothermometer. Absolute TEX86H temperature estimates are generally higher than those of U37k', though this difference (crenarchaeota and haptophyta experienced similar temperature variations. During occasional events (<5% of the analyzed time span), however, the TEX86H exhibits considerably higher absolute temperature estimates than the U37k'. Comparison with Mg/Ca records of planktonic foraminifera as well as other Mediterranean TEX86 and U37k' records suggests that part of this divergence may be attributed to seasonal differences, that is, with TEX86H reflecting mainly the warm summer season while U37k' would show annual mean. Biases in the global calibration of both proxies or specific biases in the Mediterranean are an alternative, though less likely, explanation. Despite differences between absolute TEX86H and U37k' temperatures, the correlation between the two proxies (r2 = 0.59, 95% significance) provides support for the occurrence of abrupt temperature variations in the western Mediterranean during the penultimate interglacial-to-glacial cycle.

  10. GDGT and alkenone flux in the northern Gulf of Mexico: Implications for the TEX86 and UK'37 paleothermometers

    Science.gov (United States)

    Richey, Julie N.; Tierney, Jessica E.

    2016-12-01

    The TEX86 and U37K' molecular biomarker proxies have been broadly applied in downcore marine sediments to reconstruct past sea surface temperature (SST). Although both TEX86 and U37K' have been interpreted as proxies for mean annual SST throughout the global ocean, regional studies of glycerol dibiphytanyl glycerol tetraethers (GDGTs) and alkenones in sinking particles are required to understand the influence of seasonality, depth distribution, and diagenesis on downcore variability. We measure GDGT and alkenone flux, as well as the TEX86 and U37K' indices in a 4 year sediment trap time series (2010-2014) in the northern Gulf of Mexico (nGoM), and compare these data with core-top sediments at the same location. GDGT and alkenone fluxes do not show a consistent seasonal cycle; however, the largest flux peaks for both occurs in winter. U37K' covaries with SST over the 4 year sampling interval, but the U37K'-SST relationship in this data set implies a smaller slope or nonlinearity at high temperatures when compared with existing calibrations. Furthermore, the flux-weighted U37K' value from sinking particles is significantly lower than that of underlying core-top sediments, suggesting preferential diagenetic loss of the tri-unsaturated alkenone in sediments. TEX86 does not covary with SST, suggesting production in the subsurface upper water column. The flux-weighted mean TEX86 matches that of core-top sediments, confirming that TEX86 in the nGoM reflects local planktonic production rather than allochthonous or in situ sedimentary production. We explore potential sources of uncertainty in both proxies in the nGoM but demonstrate that they show nearly identical trends in twentieth century SST, despite these factors.

  11. Distribution of archaeal and bacterial glycerol dialkyl glycerol tetraethers in tropical sediments from Guadeloupe (French West Indies): implications for application of the MBT/CBT and TEX86 proxies

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    Huguet, A.; Belmahdi, I.; Fosse, C.; Grossi, V.; Derenne, S.

    2012-04-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are lipids of high molecular weight present in membranes of Archaea and some bacteria. Archaeal membranes are composed predominantly of isoprenoid GDGTs, with acyclic or ring-containg biphytanyl chains. The amount of isoprenoid GDGTs with cyclopentyl moieties was shown to increase with water temperature and variations in surface water temperature can be determined via the TEX86 proxy. Recently, another type of GDGTs, with branched instead of isoprenoid alkyl chains, has been discovered in peat and was observed to occur ubiquitously in soils and in aquatic environments. Branched GDGTs were suggested to be produced in soils by still unknown bacteria. The degree of methylation of branched GDGTs, expressed in the MBT, was shown to depend on air temperature and to a lesser extent on soil pH, whereas the relative abundance of cyclopentyl rings of branched GDGTs, expressed in the CBT, was related to soil pH. The MBT/CBT proxies are increasingly used as paleoclimate proxies. The aim of this study was to investigate the distribution of GDGTs in tropical sediments from Guadeloupe (French West Indies). Surficial sediment samples were collected in four coastal water ponds: two located in Grande-Terre and two in a smaller island named La Désirade, 10 km east from Grande-Terre. GDGTs either present as core lipids (CLs; presumed of fossil origin) or derived from intact polar lipids (IPLs; markers for living cells) were analysed. A large part of archaeal GDGTs was present as IPLs (40-50% of total extractable archaeal GDGTs) in all sites. The proportion of IPL GDGTs of bacterial origin with respect to the total pool (CLs +IPLs) was 25-30% in the sediments from La Désirade and ~ 50% in the upper sediment layers from Grande-Terre. Interestingly, the distribution of archaeal and bacterial GDGTs differed between the four sites, as shown by the higher values of the TEX86 and MBT in sediments from La Désirade (TEX86~0.80; MBT~0

  12. The Thermal History of the East African Rift Lakes Region Since the Last Glacial Maximum Using TEX86 Paleothermometry

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    Berke, M. A.; Johnson, T. C.; Werne, J. P.; Schouten, S.; Sinninghe Damsté, J. S.

    2008-12-01

    We present preliminary results from a study using the TEX86 temperature proxy from sediments of East African Rift Lakes (including Lakes Turkana, Albert, and Malawi) to reconstruct the thermal history of tropical Africa for the last ~ 20,000 years at a subcentennial to multicentennial resolution. The TEX86 proxy, based on tetraether membrane lipids produced by lacustrine Crenarchaeota, has been shown to be successful at recording lake surface temperatures of some large lakes, including Lakes Malawi and Tanganyika, while providing unreasonable surface temperatures for lakes that receive a large input of soil material. The East African Rift Lakes are climatically sensitive, with the majority of water loss due to evaporation rather than outflow. Thus, they are useful for paleoclimate studies, being sensitive to even small changes in aridity. Temperature records from the northern and central basins of Lake Malawi agree well and fall within modern surface lake temperatures. A 2.5°C cooling is evident during the Younger Dryas in the northern basin record, with no response seen in the central basin. We are currently investigating mechanisms to explain why both records show a gradual cooling of 3°C during the late Holocene. Lake Albert shows an intriguing two-step cooling during the Younger Dryas, reaching temperatures 2.5°C lower than temperatures preceding or following this interval. The temperature record of Lake Turkana shows an interesting ~ 500 year cyclicity of low temperatures punctuated by abrupt warming events. Lakes Turkana and Albert show TEX86 paleotemperatures considerably lower (8°C cooler in Lake Albert and ~ 4°C cooler in Lake Turkana) than modern surface water temperatures. Although these records appear to fall in the range of temporal variability, these temperature discrepancies may indicate varying Crenarcheotal populations between lakes or other influencing factors.

  13. Holocene TEX86 temperature reconstructions from Lake Turkana, East Africa

    Science.gov (United States)

    Berke, M. A.; Johnson, T. C.; Werne, J. P.; Schouten, S.; Sinninghe Damsté, J. S.

    2009-12-01

    We present new high resolution Holocene lake surface temperature records from Lake Turkana, East Africa. These two TEX86 reconstructions, from the northern and southern basins of the lake, capture ~90 year resolution of climate patterns seen in this closed-basin system, as well as the thermal water dynamics between the two basins. The modern lake experiences surface temperatures in the northern basin ~1-3 °C warmer than the southern basin, due to upwelling in the southern basin induced by the predominant southerly winds. The paleotemperature records show parallel trends to this modern basinal temperature gradient, averaging ~1.5 °C warmer in the northern basin than the southern during the ~2000 years of record overlap (~450-2500 ybp). Some temperature intervals with coverage in both basins show strong agreement (i.e. ~2600-2000 Cal ybp), whereas increased wind-generated upwelling events may be responsible for periods that appear strongly antiphased (i.e. 2000-1600 Cal ybp) between basins. There does not appear to be any evidence of warming into the Medieval Warm Period (MWP, ~800-1200AD) or cooling at the start of the Little Ice Age (LIA, ~600 ybp). The southern basin temperature record indicates a substantial ~5 °C warming culminating in a thermal maximum ~5ka, immediately followed by ~3 °C cooling. This supports previous observations of an anomalously warm interval ~5ka documented in lake surface temperature records from Lakes Malawi and Tanganyika. A similar Holocene thermal maximum ~5ka has also been described from the Indian Ocean off the coast of Somalia (3°11’N, 50°26’E) (Bard et al., 1997). The abundance of these records now point to this being the warmest or one of the warmest intervals in the Holocene in tropical East Africa and indicates this may be a widespread regional climate response. Although these temperature trends appear reasonable, overall TEX86 temperatures for Lake Turkana are considerably lower than modern surface water temperatures

  14. A "tropical" Early Eocene marine environment on the Antarctic margin: TEX86 results from IODP expedition 318

    Science.gov (United States)

    Bendle, J. A.; Bijl, P.; Toney, J. L.; Pross, J.; Contreras, L.; Schouten, S.; Roehl, U.; Tauxe, L.; Huber, M.; Brinkhuis, H.; Scientific Team of IODP Drilling Leg 318

    2011-12-01

    The early Eocene was characterised by high pCO2 (ca.1,000 to more than 2,000ppm) and mean global temperatures that reached a long-term maximum. Relative to the present day, meridional temperature gradients were unusually low, with warmer equatorial regions and much warmer subtropical Arctic and mid-latitude climates. Yet global climatic conditions during this pre-glacial interval have remained poorly constrained, as only a few temperature records are available portraying the Cenozoic climatic evolution of the high southern latitudes. Here we present dinoflagellate cyst assemblages and organic geochemical tetraether based sea-surface temperature estimates from IODP expedition 318, extracted from bio- and magnetostratigraphically dated, late early to early middle Eocene sediments recovered at Site U1356. For the first time, we reconstruct marine temperatures and ecological conditions from the Eocene Greenhouse world in direct proximity to the Antarctic continent. Early Eocene dinocyst assemblages are dominated by tropical dinocyst genus Apectodinium, whilst TEX86 results indicate persistent and remarkable warmth, with the magnitude of the reconstructed SSTs dependent on the applied calibration: TEX86-L = 20 - 26°C (Av. 23°C); TEX86-H = 27 - 33°C (Av. 32°C). Our marine based proxies are just several strands from multiple independent lines of evidence emerging from the Early Eocene of the Wilkes Land Antarctic margin, including: pollen, terrestrial biomarkers (e.g. MBT/CBT-MAT estimates of 22 - 27°C , Av. 26°C), compound specific plant wax D/H measurements and clay minerals. Taken together, this evidence of very high temperatures, thermophilic fauna, an invigorated hydrological cycle, chemically weathered soils and well developed wetlands gives a very compelling picture of environmental conditions comparable to the modern tropics. These results confirm that exceptionally warm polar-regions are a feature common to reconstructed Greenhouse periods. Such

  15. Fluxes and distribution of tetraether lipids in an equatorial African lake: Constraints on the application of the TEX 86 palaeothermometer and BIT index in lacustrine settings

    Science.gov (United States)

    Sinninghe Damsté, Jaap S.; Ossebaar, Jort; Abbas, Ben; Schouten, Stefan; Verschuren, Dirk

    2009-07-01

    The distribution of isoprenoid and branched glycerol dialkyl glycerol tetraether (GDGT) lipids was studied in material from various sources in and around Lake Challa, a crater lake on the southeastern slope of Mt. Kilimanjaro (Tanzania), to examine the provenance of GDGTs in lake sediments and their potential application as palaeoenvironmental and palaeoclimatic proxies. The study material included samples collected at monthly intervals in a sediment trap over one complete annual cycle, particles suspended in the stratified water column, profundal surface sediments, and soils surrounding the lake. The sediment trap time series revealed that crenarchaeol and related isoprenoid GDGTs were predominantly produced in January and February, following the locally prominent short rain season (November-December). The TEX 86-inferred temperature derived from sedimenting particles corresponded well with lake surface-water temperature at this time of largest crenarchaeol flux. Molecular ecological analysis showed that Group 1.1a and 1.1b crenarchaeota are the most likely source organisms of these GDGTs. GDGT-0 in the lake sediments does not only originate from lake surface-dwelling crenarchaeota but seems predominantly derived from archaea residing in the deeper, anoxic part of the water column. The main flux of branched GDGTs to the sediment was during the short rain season and is most probably derived from eroded catchment soils in surface run-off. However, a contribution from in-situ production of branched GDGTs in the lake sediment or water, or in groundwater cannot be fully excluded. We conclude that palaeoclimatic reconstruction based on branched GDGT distributions in lake sediments should only be performed when the origin of those branched GDGTs is well constrained.

  16. Proxy comparisons for Paleogene sea water temperature reconstructions

    Science.gov (United States)

    de Bar, Marijke; de Nooijer, Lennart; Schouten, Stefan; Ziegler, Martin; Sluijs, Appy; Reichart, Gert-Jan

    2017-04-01

    Several studies have reconstructed Paleogene seawater temperatures, using single- or multi-proxy approaches (e.g. Hollis et al., 2012 and references therein), particularly comparing TEX86 with foraminiferal δ18O and Mg/Ca. Whereas trends often agree relatively well, absolute temperatures can differ significantly between proxies, possibly because they are often applied to (extreme) climate events/transitions (e.g. Sluijs et al., 2011), where certain assumptions underlying the temperature proxies may not hold true. A more general long-term multi-proxy temperature reconstruction, is therefore necessary to validate the different proxies and underlying presumed boundary conditions. Here we apply a multi-proxy approach using foraminiferal calcite and organic proxies to generate a low-resolution, long term (80 Myr) paleotemperature record for the Bass River core (New Jersey, North Atlantic). Oxygen (δ18O), clumped isotopes (Δ47) and Mg/Ca of benthic foraminifera, as well as the organic proxies MBT'-CBT, TEX86H, U37K' index and the LDI were determined on the same sediments. The youngest samples of Miocene age are characterized by a high BIT index (>0.8) and fractional abundance of the C32 1,15-diol (>0.6; de Bar et al., 2016) and the absence of foraminifera, all suggesting high continental input and shallow depths. The older sediment layers (˜30 to 90 Ma) display BIT values and C32 1,15-diol fractional abundances global transition from the Cretaceous to Eocene greenhouse world into the icehouse climate. The TEX86H sea surface temperature (SST) record shows a gradual cooling over time of ˜35 to 20 ˚ C, whereas the δ18O-derived bottom water temperatures (BWTs) decrease from ˜20 to 10 ˚ C, and the Mg/Ca and Δ47-derived BWTs decrease from ˜25 to 15 ˚ C. The absolute temperature difference between the δ18O and Δ47, might be explained by local variations in seawater δ18O composition. Similarly, the difference in Mg/Ca- and δ18O-derived BWTs is likely caused by

  17. Cretaceous sea-surface temperature evolution: Constraints from TEX86 and planktonic foraminiferal oxygen isotopes

    OpenAIRE

    O'Brien, Charlotte L.; Robinson, Stuart A.; Pancost, Richard D.; Sinninghe Damsté, Jaap S.; Schouten, Stefan; Lunt, Daniel J.; Alsenz, Heiko; Bornemann, André; Bottini, Cinzia; Brassell, Simon C.; Farnsworth, Alexander; Forster, Astrid; Huber, Brian T.; Inglis, Gordon N.; Jenkyns, Hugh C.

    2017-01-01

    It is well established that greenhouse conditions prevailed during the Cretaceous Period (~ 145–66 Ma). Determining the exact nature of the greenhouse-gas forcing, climatic warming and climate sensitivity remains, however, an active topic of research. Quantitative and qualitative geochemical and palaeontological proxies provide valuable observational constraints on Cretaceous climate. In particular, reconstructions of Cretaceous sea-surface temperatures (SSTs) have been revolutionised firstly...

  18. Occurrence and distribution of tetraether membrane lipids in soils: implications for the use of the TEX86 proxy and the BIT index

    NARCIS (Netherlands)

    Weijers, J.W.H.; Schouten, S.; Spaargaren, O.C.; Sinnige Damsté, J.S.

    2006-01-01

    A diverse collection of globally distributed soil samples was analyzed for its glycerol dialkyl glycerol tetraether (GDGT) membrane lipid content. Branched GDGTs, derived from anaerobic soil bacteria, were the most dominant and were found in all soils. Isoprenoid GDGTs, membrane lipids of Archaea,

  19. Preliminary TEX86 temperatures and a lake level record of tropical climate extremes derived from sediment cores and seismic stratigraphy from Lake Turkana, East Africa

    Science.gov (United States)

    Morrissey, A. J.; Scholz, C. A.; Russell, J. M.

    2012-12-01

    Lake Turkana is the largest lake in the Eastern Branch of the East African Rift System and records hydrologic conditions of a region spanning nearly 2.5 degrees of latitude (~2.0 - 4.5 degrees N) in the African tropics. New data suggest the Turkana region likely experienced much wetter and cooler climate over several intervals since the latest Pleistocene. Lake level was extremely low twice during the latest Pleistocene, evidenced by depositional hiatuses in high-resolution CHIRP seismic reflection data that correlate with sediments that have low water-content, abundant sand, and low total organic carbon (TOC as low as Lake Turkana, like many lakes in northern tropical Africa, had a wetter climate during the African Humid Period. Intervals of high lake levels (up to ~440 m amsl) are indicated by flat-lying, laterally continuous, low-amplitude reflections that correlate in sediment cores to dark, fine-grained, laminated sediment with high TOC (up to ~6%). Calcium carbonate accumulation during this time period is nearly 0%, and combined with evidence of laminated, unbioturbated sediment suggests a fresh, stratified lake with anoxic bottom waters. During the early mid-Holocene, lake level began to fall to close to present levels (~365 m amsl). Sediments deposited during this time period have low but variable organic carbon content (~0.5 - ~2%) and are much higher in inorganic carbon (from fine-grained calcite precipitation). A moderate lowstand during the late Holocene is indicated by an erosional unconformity seen down to ~40 m below the current lake surface in several seismic profiles. This record of lake level extremes suggests highly variable rainfall patterns, forced by migration of the Intertropical Convergence Zone) across tropical East Africa over the last 20,000 years. More than 50 sediment samples from 3 piston cores represent a continuous record of TEX86 temperature from ~20,000 years ago to modern. The generally low (lake surface temperature. The range of

  20. Oligocene-Miocene paleoceanographic changes offshore the Wilkes Land Margin, Antarctica: dinoflagellate cyst and TEX86 analyses of DSDP Site 269

    Science.gov (United States)

    Bijl, Peter; Boterblom, Wilrieke H.; Sangiorgi, Francesca; Hartman, Julian D.; Peterse, Francien

    2017-04-01

    Although a lot of research has been conducted to characterize the onset of Antarctic glaciation at the Eocene-Oligocene transition, little is known about the subsequent evolution and fluctuations of the size of the Antarctic Ice Sheet (AIS). The discrepancy between the conclusions of Foster and Rohling (2013) (insensitive global cryosphere between 400-650 ppmv CO2) and variations in benthic foraminiferal δ18O records (0.5-1 ‰) illustrate the uncertainty in particularly the East AIS variability during the Oligocene and Miocene. Increasing awareness of the importance of oceanographic conditions on ice sheet melt emphasize the need to directly infer ice sheet volume fluctuations from sedimentary archives close to the Antarctic margin. In this study, dinoflagellate cyst (dinocyst) assemblages, dinocyst-based biostratigraphy and TEX86 from Deep Sea Drilling Project Site 269, offshore the Wilkes Land Margin (WLM), were used to reconstruct the paleoenvironment and paleoceanographic setting during the Oligocene and Miocene. Preliminary results are indicative of open ocean conditions, Southern Ocean fronts and high productivity waters. Furthermore, biomarker species were found, which are useful for stratigraphic dating. Research conducted at the continental rise of the WLM (Site U1356), by Bijl et al. (in prep.), has allowed for the calibration of dinocysts events of the Oligocene-Miocene Southern Ocean to the international time scale. Comparing the results of Site 269 to Site U1356 can thus provide an age constraint for this record. Correlating paleoceanographic changes between sites can provide insights into the variability of the EAIS during the Oligocene and Miocene, and will contribute to improving predictions of future changes in the Antarctic ice sheet.

  1. Molecular proxies for paleoclimatology

    Science.gov (United States)

    Eglinton, Timothy I.; Eglinton, Geoffrey

    2008-10-01

    We summarize the applications of molecular proxies in paleoclimatology. Marine molecular records especially are proving to be of value but certain environmentally persistent compounds can also be measured in lake sediments, loess deposits and ice cores. The fundamentals of this approach are the molecular parameters, the compound abundances and carbon, hydrogen, nitrogen and oxygen isotopic contents which can be derived by the analysis of sediment extracts. These afford proxy measures which can be interpreted in terms of the conditions which control climate and also reflect its operation. We discuss two types of proxy; those of terrigenous and those of aquatic origin, and exemplify their application in the study of marine sediments through the medium of ten case studies based in the Atlantic, Mediterranean and Pacific Oceans, and in Antarctica. The studies are mainly for periods in the present, the Holocene and particularly the last glacial/interglacial, but they also include one study from the Cretaceous. The terrigenous proxies, which are measures of continental vegetation, are based on higher plant leaf wax compounds, i.e. long-chain (circa C 30) hydrocarbons, alcohols and acids. They register the relative contributions of C 3 vs. C 4 type plants to the vegetation in the source areas. The two marine proxies are measures of sea surface temperatures (SST). The longer established one, (U 37K') is based on the relative abundances of C 37 alkenones photosynthesized by unicellular algae, members of the Haptophyta. The newest proxy (TEX 86) is based on C 86 glycerol tetraethers (GDGTs) synthesized in the water column by some of the archaeal microbiota, the Crenarchaeota.

  2. Unusual Red Sea-Type GDGT Distributions during the Early Paleogene: A Proxy for Enhanced Salinity?

    Science.gov (United States)

    Pancost, R. D.; Inglis, G.; Farnsworth, A.; Lunt, D. J.; Foster, G. L.; Hollis, C. J.; Jardine, P. E.

    2014-12-01

    TEX86, an organic palaeothermometer based upon the distribution of isoprenoidal glycerol dialkyl glycerol tetraethers (GDGTs) in marine Thaumarchaeota, is regularly used to reconstruct spatial and temporal sea surface temperature patterns, especially in older (Mesozoic and Palaeogene) settings. The TEX86 proxy assumes that Thaumarchaeota in modern oceans are representative of those living in ancient settings, but even in today's oceans Thaumarchaeotal phylogeny is diverse. In the Red Sea, phylogenetically distinct archaeal communities occur both above and below the thermocline and correspond to core-top sediments in which TEX86 values consistently overestimate satellite-derived sea surface temperature (SST) by 6-8°C [1]. These elevated SSTs are associated with an unusual GDGT distribution characterised by low GDGT-0 (10%). Here we propose the %GDGTRS index (= ([GDGT-4']/[GDGT-4']+[GDGT-0])*100) as a way to identify Red Sea-type GDGT distributions in ancient sediments. In a Paleogene (65-34Ma) compilation, Red Sea-type GDGT distributions are common and geographically widespread, and could lead to SST overestimates. The underlying ecological controls that govern the occurrence of these distributions remain unclear, but they are especially common during times of elevated warmth (i.e. EECO, PETM). During the EECO and the PETM, the occurrence of Red Sea-type GDGT distributions coincides with the presence of hypersaline and/or lagoonal dinocysts in at least four global localities. We suggest that the high %GDGTRS values during these very hot intervals reflect the presence of unique Thaumarchaeotal or Euryarchaeotal clusters responding to the development of more saline conditions, similar to or perhaps exceeding those observed in the Red Sea today. 1. Trommer, G. et al., 2009. Distribution of Crenarchaeota tetraether membrane lipids in surface sediments from the Red Sea. Organic Geochemistry, v. 40, p. 724-731

  3. Intact polar and core glycerol dibiphytanyl glycerol tetraether lipids in the Arabian Sea oxygen minimum zone: I. Selective preservation and degradation in the water column and its consequences for the TEX86

    NARCIS (Netherlands)

    Schouten, S.; Pitcher, A.; Hopmans, E.C.; Villaneuva, L.; Bleijswijk, J. van; Sinninghe Damsté, J.S.

    2012-01-01

    Glycerol dibiphytanyl glycerol tetraether lipids (GDGTs) have proven to be important biomarker lipids for specific archaeal lineages and their distribution is used as a paleotemperature proxy. In this study, we analyzed GDGTs in suspended particles in the water column of the Arabian Sea at

  4. Multi-proxy constraints on sapropel formation during the late Pliocene of central Mediterranean (southwest Sicily)

    Science.gov (United States)

    Plancq, Julien; Grossi, Vincent; Pittet, Bernard; Huguet, Carme; Rosell-Melé, Antoni; Mattioli, Emanuela

    2015-06-01

    The late Pliocene (Piacenzian) in the Mediterranean region was punctuated by short-lived episodes of widespread deposition of organic-rich sedimentary layers known as sapropels. The causes of their formation remain a long-standing debate in the science community, and require disentangling the roles of climatic/oceanographic processes that triggered higher primary productivity or enhanced organic matter preservation. The lack of data, especially of sea temperatures at sufficient temporal resolution, is one of the main challenges to solve this debate. Here, we present new organic geochemistry and micropaleontological data from the late Pliocene at Punta Grande/Punta Piccola sections (southwest Sicily) that allow untangling the mechanisms that favored the formation of two sapropel series (noted S and A) in the central Mediterranean area during this period. Sea surface (SSTs) and subsurface temperatures were estimated using three distinct organic geochemical proxies namely the alkenone unsaturation index (UK‧37), the long-chain diol index (LDI) and the tetraether index (TEX86). Reconstructed SSTs are relatively stable throughout the late Pliocene and ∼4 °C higher than modern Mediterranean SSTs, which is consistent with the climatic conditions inferred for this period from paleoclimate modeling. An increase in SST is, however, recorded by UK‧37 and LDI proxies across each sapropel horizon, supporting that the two sapropel series S and A were formed during warmer climate conditions. The comparison of SST data with variations in accumulation rates of total organic carbon and lipid-biomarkers (alkenones, long-chain alkyl diols, archaeal and bacterial tetraethers), and with changes in calcareous nannofossil assemblages, indicates that the studied sapropels might have formed under different environmental conditions. The first series of sapropels (S), deposited between 3.1 and 2.8 Ma, is likely due to a better preservation of organic matter, induced by the development

  5. Late Oligocene to Late Miocene Antarctic Climate Reconstructions Using Molecular and Isotopic Biomarker Proxies

    Science.gov (United States)

    Duncan, B.; Mckay, R. M.; Bendle, J. A.; Naish, T.; Levy, R. H.; Ventura, G. T.; Moossen, H. M.; Krishnan, S.; Pagani, M.

    2015-12-01

    Major climate and environmental changes occurred during late Oligocene to the late Miocene when atmospheric CO2 ranged between 500 and 300ppm, indicating threshold response of Antarctic ice sheets and climate to relatively modest CO2 variations. This implies that the southern high latitudes are highly sensitive to feedbacks associated with changes in global ice sheet and sea-ice extent, as well as terrestrial and marine ecosystems. This study focuses on two key intervals during the evolution of the Antarctic Ice Sheet: (1) The Late Oligocene and the Oligocene/Miocene boundary, when the East Antarctic Ice Sheet expanded close to present day volume following an extended period of inferred warmth. (2) The Mid-Miocene Climate Optimum (MMCO ~17-15 Ma), a period of global warmth and moderately elevated CO2 (350->500 ppm) which was subsequently followed by rapid cooling at 14-13.5 Ma. Reconstructions of climate and ice sheet variability, and thus an understanding of the various feedbacks that occurred during these intervals, are hampered by a lack of temperature and hydroclimate proxy data from the southern high latitudes. We present proxy climate reconstructions using terrestrial and marine organic biomarkers that provide new insights into Antarctica's climate evolution, using Antarctic drill cores and outcrop samples from a range of depositional settings. Bacterial ether-lipids have been analysed to determine terrestrial mean annual temperatures and soil pH (via the methylation and cyclisation indexes of branched tetraethers - MBT and CBT, respectively). Tetraether-lipids of crenarchaeota found in marine sediments sampled from continental shelves around Antarctica have been used to derive sea surface temperatures using the TEX86 index. Compound specific stable isotopes on n-alkanes sourced from terrestrial plants have been analysed to investigate changes in the hydrological and carbon cycles.

  6. Munchausen syndrome by proxy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001555.htm Munchausen syndrome by proxy To use the sharing features on this page, please enable JavaScript. Munchausen syndrome by proxy is a mental illness and ...

  7. Climate variability in the SW Indian Ocean from an 8000-yr long multi-proxy record in the Mauritian lowlands shows a middle to late Holocene shift from negative IOD-state to ENSO-state

    NARCIS (Netherlands)

    De Boer, Erik J.; Tjallingii, Rik; Vélez, Maria I.; Rijsdijk, Kenneth F.; Vlug, Anouk; Reichart, Gert-Jan; Prendergast, Amy L.; de Louw, Perry G B; Florens, F. B Vincent; Baider, Cláudia; Hooghiemstra, Henry

    2014-01-01

    A multi-proxy reconstruction of a sediment core from the Tatos basin in the Mauritian lowlands reveals a dynamic environmental history during the last 8000 years. Under influence of sea level rise, the basin progressed from a wetland to a shallow lake between 8000 and 2500cal yr BP and it slowly

  8. Here be web proxies

    DEFF Research Database (Denmark)

    Weaver, Nicholas; Kreibich, Christian; Dam, Martin

    2014-01-01

    HTTP proxies serve numerous roles, from performance enhancement to access control to network censorship, but often operate stealthily without explicitly indicating their presence to the communicating endpoints. In this paper we present an analysis of the evidence of proxying manifest in executions...... of the ICSI Netalyzr spanning 646,000 distinct IP addresses ("clients"). To identify proxies we employ a range of detectors at the transport and application layer, and report in detail on the extent to which they allow us to fingerprint and map proxies to their likely intended uses. We also analyze 17...

  9. Novel Quantum Proxy Signature without Entanglement

    Science.gov (United States)

    Xu, Guang-bao

    2015-08-01

    Proxy signature is an important research topic in classic cryptography since it has many application occasions in our real life. But only a few quantum proxy signature schemes have been proposed up to now. In this paper, we propose a quantum proxy signature scheme, which is designed based on quantum one-time pad. Our scheme can be realized easily since it only uses single-particle states. Security analysis shows that it is secure and meets all the properties of a proxy signature, such as verifiability, distinguishability, unforgeability and undeniability.

  10. Jemen - the Proxy War

    Directory of Open Access Journals (Sweden)

    Magdalena El Ghamari

    2015-12-01

    Full Text Available The military operation in Yemen is significant departure from Saudi Arabia's foreign policy tradition and customs. Riyadh has always relied on three strategies to pursue its interests abroad: wealth, establish a global network and muslim education and diplomacy and meadiation. The term "proxy war" has experienced a new popularity in stories on the Middle East. A proxy war is two opposing countries avoiding direct war, and instead supporting combatants that serve their interests. In some occasions, one country is a direct combatant whilst the other supporting its enemy. Various news sources began using the term to describe the conflict in Yemen immediately, as if on cue, after Saudi Arabia launched its bombing campaign against Houthi targets in Yemen on 25 March 2015. This is the reason, why author try to answer for following questions: Is the Yemen Conflict Devolves into Proxy War? and Who's fighting whom in Yemen's proxy war?" Research area includes the problem of proxy war in the Middle East. For sure, the real problem of proxy war must begin with the fact that the United States and its NATO allies opened the floodgates for regional proxy wars by the two major wars for regime change: in Iraq and Libya. Those two destabilising wars provided opportunities and motives for Sunni states across the Middle East to pursue their own sectarian and political power objectives through "proxy war".

  11. Ecological and isotopic insights to the origin of archaeal tetraethers in marine sediments

    Science.gov (United States)

    Pearson, A.; Hurley, S. J.

    2012-12-01

    Thaumarchaeota, formerly known as Marine Group I Crenarchaeota, are believed to be the primary source of the isoprenoidal glycerol dialkyl glycerol tetraether lipids (GDGTs) found in the environment. Enrichment mesocosms and empirical correlations for marine sediments (TEX86) show a positive relationship between environmental temperature and the number of cyclopentyl or cyclohexyl rings contained within the GDGT structure. The TEX86 paleotemperature proxy has been applied across a large temporal range of geologic events and to sediments of widely varying depositional and diagenetic history. TEX86 assumes a direct correlation between the preserved GDGT ratios and SST. A number of fundamental assumptions underlie this correlation, including that: (1) GDGTs transported to the sediments reflect biomass of surface origin, (2) GDGTs produced by Archaea deeper in the water column should reflect deep temperatures and are not exported, and (3) community variations - including the potential contribution of GDGTs by Group II Euryarchaeota - do not appreciably affect the overall TEX86-SST relationship. Here we discuss evidence that questions all three of these assumptions and propose strategies for further understanding how GDGTs record paleoenvironments. These new approaches include greater application of physiological and culture studies; concurrent measurements of δ13C, Δ14C and D/H ratios of GDGTs; and cross-correlations with other paleotemperature proxies.

  12. Jemen - the Proxy War

    OpenAIRE

    Magdalena El Ghamari

    2015-01-01

    The military operation in Yemen is significant departure from Saudi Arabia's foreign policy tradition and customs. Riyadh has always relied on three strategies to pursue its interests abroad: wealth, establish a global network and muslim education and diplomacy and meadiation. The term "proxy war" has experienced a new popularity in stories on the Middle East. A proxy war is two opposing countries avoiding direct war, and instead supporting combatants that serve their interests. In some occas...

  13. New proxy replacement algorithm for multimedia streaming

    Science.gov (United States)

    Wong, Hau Ling; Lo, Kwok-Tung

    2001-11-01

    Proxy servers play an important role in between servers and clients in various multimedia systems on the Internet. Since proxy servers do not have an infinite-capacity cache for keeping all the continuous media data, the challenge for the replacement policy is to determine which streams should be cached or removed from the proxy server. In this paper, a new proxy replacement algorithm, named the Least Popular Used (LPU) caching algorithm, is proposed for layered encoded multimedia streams in the Internet. The LPU method takes both the short-term and long-term popularity of the video into account in determining the replacement policy. Simulation evaluation shows that our proposed scheme achieves better results than some existing methods in term of the cache efficiency and replacement frequency under both static and dynamic access environments.

  14. Proxy Smart Card Systems

    OpenAIRE

    Cattaneo, Giuseppe; Faruolo, Pompeo; Palazzo, Vincenzo; Visconti, Ivan

    2010-01-01

    International audience; The established legal value of digital signatures and the growing availability of identity-based digital services are progressively extending the use of smart cards to all citizens, opening new challenging scenarios. Among them, motivated by concrete applications, secure and practical delegation of digital signatures is becoming more and more critical. Unfortunately, secure delegation systems proposed so far (e.g., proxy signatures) include various drawbacks for any pr...

  15. Cretaceous sea-surface temperature evolution : Constraints from TEX 86 and planktonic foraminiferal oxygen isotopes

    NARCIS (Netherlands)

    O'Brien, Charlotte L.; Robinson, Stuart A.; Pancost, Richard D.; Sinninghe Damsté, Jaap S.; Schouten, Stefan; Lunt, Daniel J.; Alsenz, Heiko; Bornemann, André; Bottini, Cinzia; Brassell, Simon C.; Farnsworth, Alexander; Forster, Astrid; Huber, Brian T.; Inglis, Gordon N.; Jenkyns, Hugh C.; Linnert, Christian; Littler, Kate; Markwick, Paul; Mcanena, Alison; Mutterlose, Jörg; Naafs, B. David A.; Püttmann, Wilhelm; Sluijs, Appy; van Helmond, Niels A.G.M.; Vellekoop, Johan; Wagner, Thomas; Wrobel, Neil E.

    2017-01-01

    It is well established that greenhouse conditions prevailed during the Cretaceous Period (~ 145–66 Ma). Determining the exact nature of the greenhouse-gas forcing, climatic warming and climate sensitivity remains, however, an active topic of research. Quantitative and qualitative geochemical and

  16. Ecology and membrane lipid distribution of marine Crenarchaeota: Implications for TEX86 paleothermometry

    NARCIS (Netherlands)

    Wuchter, Cornelia

    2006-01-01

    Archaea form one of the three domains of life on Earth and together with the bacteria form the prokaryotes. In the marine environment planktonic Archaea consist of two major groups, the Crenarchaeota and the Euryarchaeota of which the former appears to be the most abundant and may account for ca.

  17. Ecology and membrane lipid distribution of marine Crenarchaeota : Implications for TEX86 paleothermometry

    NARCIS (Netherlands)

    Wuchter, C.

    2006-01-01

    Archaea form one of the three domains of life on Earth and together with the bacteria form the prokaryotes. In the marine environment planktonic Archaea consist of two major groups, the Crenarchaeota and the Euryarchaeota of which the former appears to be the most abundant and may account for ca.

  18. Ecology and membrane lipid distribution of marine Crenarchaeota : Implications for TEX86 paleothermometry

    OpenAIRE

    Wuchter, Cornelia

    2006-01-01

    Archaea form one of the three domains of life on Earth and together with the bacteria form the prokaryotes. In the marine environment planktonic Archaea consist of two major groups, the Crenarchaeota and the Euryarchaeota of which the former appears to be the most abundant and may account for ca. 20% of all prokaryotic cells in the global ocean. Despite the fact that marine Crenarchaeota constitute a substantial fraction of the picoplankton in the world oceans, little is known about their bas...

  19. Munchausen syndrome by proxy

    Directory of Open Access Journals (Sweden)

    Jovanović Aleksandar A.

    2005-01-01

    Full Text Available This review deals with bibliography on Munchausen syndrome by proxy (MSbP. The name of this disorder was introduced by English psychiatrist Roy Meadow who pointed to diagnostic difficulties as well as to serious medical and legal connotations of MSbP. MSbP was classified in DSM-IV among criteria sets provided for further study as "factitious disorder by proxy", while in ICD-10, though not explicitly cited, MSbP might be classified as "factitious disorders" F68.1. MSbP is a special form of abuse where the perpetrator induces somatic or mental symptoms of illness in the victim under his/her care and then persistently presents the victims for medical examinations and care. The victim is usually a preschool child and the perpetrator is the child's mother. Motivation for such pathological behavior of perpetrator is considered to be unconscious need to assume sick role by proxy while external incentives such as economic gain are absent. Conceptualization of MSbP development is still in the domain of psychodynamic speculation, its course is chronic and the prognosis is poor considering lack of consistent, efficient and specific treatment. The authors also present the case report of thirty-three year-old mother who had been abusing her nine year-old son both emotionally and physically over the last several years forcing him to, together with her, report to the police, medical and educational institutions that he had been the victim of rape, poisoning and beating by various individuals, especially teaching and medical staff. Mother manifested psychosis and her child presented with impaired cognitive development, emotional problems and conduct disorder.

  20. [Munchausen by proxy syndrome].

    Science.gov (United States)

    Depauw, A; Loas, G; Delhaye, M

    2015-01-01

    The Munchausen syndrome by proxy (MSBP) was first described in 1977 by the English paediatrician Roy Meadow. The MSBP is an extremely complicated diagnosis because of the difficulty in finding the incriminating evidence of its existence and because of the ethical issue it raises for caregivers. Its implications from a medical, psychological and legal point of view raise difficult questions for any professional confronted to it. In this article we will first present the case of a 16-year-old teenager who had been bedridden in hospital for a year, before an atypical form of MSBP was finally diagnosed, after a stay in a child and adolescent psychiatry unit. We will then discuss this case in light of a literature review on the MSBP.

  1. Proxy consent: moral authority misconceived.

    Science.gov (United States)

    Wrigley, A

    2007-09-01

    The Mental Capacity Act 2005 has provided unified scope in the British medical system for proxy consent with regard to medical decisions, in the form of a lasting power of attorney. While the intentions are to increase the autonomous decision making powers of those unable to consent, the author of this paper argues that the whole notion of proxy consent collapses into a paternalistic judgement regarding the other person's best interests and that the new legislation introduces only an advisor, not a proxy with the moral authority to make treatment decisions on behalf of another. The criticism is threefold. First, there is good empirical evidence that people are poor proxy decision makers as regards accurately representing other people's desires and wishes, and this is therefore a pragmatically inadequate method of gaining consent. Second, philosophical theory explaining how we represent other people's thought processes indicates that we are unlikely ever to achieve accurate simulations of others' wishes in making a proxy decision. Third, even if we could accurately simulate other people's beliefs and wishes, the current construction of proxy consent in the Mental Capacity Act means that it has no significant ethical authority to match that of autonomous decision making. Instead, it is governed by a professional, paternalistic, best-interests judgement that undermines the intended role of a proxy decision maker. The author argues in favour of clearly adopting the paternalistic best-interests option and viewing the proxy as solely an advisor to the professional medical team in helping make best-interests judgements.

  2. Private Computing with Untrustworthy Proxies

    NARCIS (Netherlands)

    Gedrojc, B.

    2011-01-01

    The objective of this thesis is to preserve privacy for the user while untrustworthy proxies are involved in the communication and computation i.e. private computing. A basic example of private computing is an access control system (proxy) which grants access (or not) to users based on fingerprints.

  3. Robotic Vehicle Proxy Simulation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies proposes the development of a digital simulation that can replace robotic vehicles in field studies. This proxy simulation will model the...

  4. Reconstructing Holocene palaeo-environmental conditions in the Baltic: A multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

    Science.gov (United States)

    Kotthoff, Ulrich; Andrén, Elinor; Andrén, Thomas; Ash, Jeanine; Bauersachs, Thorsten; Fanget, Anne-Sophie; Granoszewski, Wojciech; Groeneveld, Jeroen; Krupinski, Nadine; Peyron, Odile; Slomp, Caroline; Stepanova, Anna; Warnock, Jonathan; van Helmond, Niels; Expedition 347 Science Party

    2016-04-01

    seasonality, but pollen-based reconstructions for Northern Europe may be hampered by plant migration effects. Palynomorph analyses are therefore complemented with analyses of lipid palaeothermometers, such as TEX86 and the long chain diol index (LDI), to reconstruct variations in Baltic Sea surface temperatures (SST). In addition, the MBT/CBT proxy is used to infer past changes in mean annual air temperatures (MAAT). Benthic foraminiferal δ18O and δ13C measurements (monospecific) and foraminifera and ostracod faunal assemblage analyses allow us to estimate bottom water salinity and environmental changes qualitatively and quantitatively. Low bottom water salinity (˜23 in bottom waters) and varying diagenesis in the Little Belt's organic-rich sediments complicates the application of benthic foraminiferal Mg/Ca as a palaeotemperature proxy. Reliable bottom water temperatures, however, are reconstructed using clumped isotope analyses of mollusc material. In addition, diatoms and the diol index (DI) are analysed to determine variation in salinity of the Baltic Sea's surface waters over the investigated time period. The results of this inter-proxy comparison study will be used to reconstruct gradients between different settings, e.g. how water column stratification developed, possibly if and how changes in seasonality occurred, and to identify the circumstances under which specific proxies may be affected by secondary impacts.

  5. Attacks on One Designated Verifier Proxy Signature Scheme

    Directory of Open Access Journals (Sweden)

    Baoyuan Kang

    2012-01-01

    Full Text Available In a designated verifier proxy signature scheme, there are three participants, namely, the original signer, the proxy signer, and the designated verifier. The original signer delegates his or her signing right to the proxy signer, then the proxy signer can generate valid signature on behalf of the original signer. But only the designated verifier can verify the proxy signature. Several designated verifier proxy signature schemes have been proposed. However, most of them were proven secure in the random oracle model, which has received a lot of criticism since the security proofs in the random oracle model are not sound with respect to the standard model. Recently, by employing Water's hashing technique, Yu et al. proposed a new construction of designated verifier proxy signature. They claimed that the new construction is the first designated verifier proxy signature, whose security does not rely on the random oracles. But, in this paper, we will show some attacks on Yu et al.'s scheme. So, their scheme is not secure.

  6. Sediment Trap Time Series of GDGT and alkenone flux in the Gulf of Mexico

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The tetraether index of C86 (TEX86) and alkenone unsaturation index (Uk37Õ) molecular biomarker proxies have been broadly applied in down-core marine sediments to...

  7. Cryptanalytic Performance Appraisal of Improved CCH2 Proxy Multisignature Scheme

    Directory of Open Access Journals (Sweden)

    Raman Kumar

    2014-01-01

    Full Text Available Many of the signature schemes are proposed in which the t out of n threshold schemes are deployed, but they still lack the property of security. In this paper, we have discussed implementation of improved CCH1 and improved CCH2 proxy multisignature scheme based on elliptic curve cryptosystem. We have represented time complexity, space complexity, and computational overhead of improved CCH1 and CCH2 proxy multisignature schemes. We have presented cryptanalysis of improved CCH2 proxy multisignature scheme and showed that improved CCH2 scheme suffered from various attacks, that is, forgery attack and framing attack.

  8. Qualitative and Quantitative Sentiment Proxies

    DEFF Research Database (Denmark)

    Zhao, Zeyan; Ahmad, Khurshid

    2015-01-01

    Sentiment analysis is a content-analytic investigative framework for researchers, traders and the general public involved in financial markets. This analysis is based on carefully sourced and elaborately constructed proxies for market sentiment and has emerged as a basis for analysing movements...... and trading volumes. The case study we use is a small market index (Danish Stock Exchange Index, OMXC 20, together with prevailing sentiment in Denmark, to evaluate the impact of sentiment on OMXC 20. Furthermore, we introduce a rather novel and quantitative sentiment proxy, that is the use of the index...

  9. Secure Mobile Agent from Leakage-Resilient Proxy Signatures

    Directory of Open Access Journals (Sweden)

    Fei Tang

    2015-01-01

    Full Text Available A mobile agent can sign a message in a remote server on behalf of a customer without exposing its secret key; it can be used not only to search for special products or services, but also to make a contract with a remote server. Hence a mobile agent system can be used for electronic commerce as an important key technology. In order to realize such a system, Lee et al. showed that a secure mobile agent can be constructed using proxy signatures. Intuitively, a proxy signature permits an entity (delegator to delegate its signing right to another entity (proxy to sign some specified messages on behalf of the delegator. However, the proxy signatures are often used in scenarios where the signing is done in an insecure environment, for example, the remote server of a mobile agent system. In such setting, an adversary could launch side-channel attacks to exploit some leakage information about the proxy key or even other secret states. The proxy signatures which are secure in the traditional security models obviously cannot provide such security. Based on this consideration, in this paper, we design a leakage-resilient proxy signature scheme for the secure mobile agent systems.

  10. Application and Network-Cognizant Proxies - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Antonio Ortega; Daniel C. Lee

    2003-03-24

    OAK B264 Application and Network-Cognizant Proxies - Final Report. Current networks show increasing heterogeneity both in terms of their bandwidths/delays and the applications they are required to support. This is a trend that is likely to intensify in the future, as real-time services, such as video, become more widely available and networking access over wireless links becomes more widespread. For this reason they propose that application-specific proxies, intermediate network nodes that broker the interactions between server and client, will become an increasingly important network element. These proxies will allow adaptation to changes in network characteristics without requiring a direct intervention of either server or client. Moreover, it will be possible to locate these proxies strategically at those points where a mismatch occurs between subdomains (for example, a proxy could be placed so as to act as a bridge between a reliable network domain and an unreliable one). This design philosophy favors scalability in the sense that the basic network infrastructure can remain unchanged while new functionality can be added to proxies, as required by the applications. While proxies can perform numerous generic functions, such as caching or security, they concentrate here on media-specific, and in particular video-specific, tasks. The goal of this project was to demonstrate that application- and network-specific knowledge at a proxy can improve overall performance especially under changing network conditions. They summarize below the work performed to address these issues. Particular effort was spent in studying caching techniques and on video classification to enable DiffServ delivery. other work included analysis of traffic characteristics, optimized media scheduling, coding techniques based on multiple description coding, and use of proxies to reduce computation costs. This work covered much of what was originally proposed but with a necessarily reduced scope.

  11. Munchausen syndrome by proxy: a case report.

    Science.gov (United States)

    Lieder, Holly S; Irving, Sharon Y; Mauricio, Rizalina; Graf, Jeanine M

    2005-01-01

    Munchausen syndrome by proxy is difficult to diagnose unless healthcare providers are astute to its clinical features and management. A case is presented to educate nurses and advanced practice nurses, of the nursing, medical, legal, and social complexities associated with Munchausen syndrome by proxy. This article also provides a brief review of the definition of Munchausen syndrome by proxy, its epidemiology, common features of the perpetrator, implications for healthcare personnel, and the legal and international ramifications of Munchausen syndrome by proxy.

  12. Shareholder Activism Through the Proxy Process

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Szilagyi, P.G.

    2009-01-01

    This paper provides evidence on the corporate governance role of shareholder-initiated proxy proposals. Previous studies debate over whether activists use proxy proposals to discipline firms or to simply advance their self-serving agendas, and whether proxy proposals are effective at all in

  13. Shareholder Activism through the Proxy Process

    NARCIS (Netherlands)

    Renneboog, L.D.R.; Szilagyi, P.G.

    2009-01-01

    This paper provides evidence on the corporate governance role of shareholderinitiated proxy proposals. Previous studies debate over whether activists use proxy proposals to discipline firms or to simply advance their self-serving agendas, and whether proxy proposals are effective at all in

  14. Proxy-produced ethnographic work: what are the problems, issues, and dilemmas arising from proxy ethnography?

    DEFF Research Database (Denmark)

    Martinussen, Marie Louise; Højbjerg, Karin; Tamborg, Andreas Lindenskov

    2018-01-01

    and positions arising from such a setup between the teacher/researcher and the proxy ethnographer/student are found to have implications for the ethnographies produced. This article’s main focus is to show how these relations and positions have not distorted the ethnographic work and the ethnographies but......This article addresses the implications of research-student cooperation in the production of empirical material. For the student to replace the experienced researcher and work under the researcher’s supervision, we call such work proxy-produced ethnographic work. The specific relations...... the research process. These ethnographic distortions will be generated and described within a framework drawn primarily on the work of sociologist Pierre Bourdieu....

  15. Measuring SIP proxy server performance

    CERN Document Server

    Subramanian, Sureshkumar V

    2013-01-01

    Internet Protocol (IP) telephony is an alternative to the traditional Public Switched Telephone Networks (PSTN), and the Session Initiation Protocol (SIP) is quickly becoming a popular signaling protocol for VoIP-based applications. SIP is a peer-to-peer multimedia signaling protocol standardized by the Internet Engineering Task Force (IETF), and it plays a vital role in providing IP telephony services through its use of the SIP Proxy Server (SPS), a software application that provides call routing services by parsing and forwarding all the incoming SIP packets in an IP telephony network.SIP Pr

  16. Munchausen Syndrome by Proxy: Identification and Intervention

    Science.gov (United States)

    Walk, Alexandra; Davies, Susan C.

    2010-01-01

    This article discusses the Munchausen syndrome by proxy (MSBP), also known as "factitious disorder by proxy" (FDBP) and fabricated and/or induced illness, which is a mental illness in which a person lies about the physical or mental well-being of a person he/she is responsible for. Most often the dynamic transpires between a mother and her child.…

  17. Proxy-assisted multicasting of video streams over mobile wireless networks

    Science.gov (United States)

    Nguyen, Maggie; Pezeshkmehr, Layla; Moh, Melody

    2005-03-01

    This work addresses the challenge of providing seamless multimedia services to mobile users by proposing a proxy-assisted multicast architecture for delivery of video streams. We propose a hybrid system of streaming proxies, interconnected by an application-layer multicast tree, where each proxy acts as a cluster head to stream out content to its stationary and mobile users. The architecture is based on our previously proposed Enhanced-NICE protocol, which uses an application-layer multicast tree to deliver layered video streams to multiple heterogeneous receivers. We targeted the study on placements of streaming proxies to enable efficient delivery of live and on-demand video, supporting both stationary and mobile users. The simulation results are evaluated and compared with two other baseline scenarios: one with a centralized proxy system serving the entire population and one with mini-proxies each to serve its local users. The simulations are implemented using the J-SIM simulator. The results show that even though proxies in the hybrid scenario experienced a slightly longer delay, they had the lowest drop rate of video content. This finding illustrates the significance of task sharing in multiple proxies. The resulted load balancing among proxies has provided a better video quality delivered to a larger audience.

  18. Slices: A shape-proxy based on planar sections

    KAUST Repository

    McCrae, James

    2011-12-01

    Minimalist object representations or shape-proxies that spark and inspire human perception of shape remain an incompletely understood, yet powerful aspect of visual communication. We explore the use of planar sections, i.e., the contours of intersection of planes with a 3D object, for creating shape abstractions, motivated by their popularity in art and engineering. We first perform a user study to show that humans do define consistent and similar planar section proxies for common objects. Interestingly, we observe a strong correlation between user-defined planes and geometric features of objects. Further we show that the problem of finding the minimum set of planes that capture a set of 3D geometric shape features is both NP-hard and not always the proxy a user would pick. Guided by the principles inferred from our user study, we present an algorithm that progressively selects planes to maximize feature coverage, which in turn influence the selection of subsequent planes. The algorithmic framework easily incorporates various shape features, while their relative importance values are computed and validated from the user study data. We use our algorithm to compute planar slices for various objects, validate their utility towards object abstraction using a second user study, and conclude showing the potential applications of the extracted planar slice shape proxies.

  19. On the use of human mobility proxies for modeling epidemics.

    Directory of Open Access Journals (Sweden)

    Michele Tizzoni

    2014-07-01

    Full Text Available Human mobility is a key component of large-scale spatial-transmission models of infectious diseases. Correctly modeling and quantifying human mobility is critical for improving epidemic control, but may be hindered by data incompleteness or unavailability. Here we explore the opportunity of using proxies for individual mobility to describe commuting flows and predict the diffusion of an influenza-like-illness epidemic. We consider three European countries and the corresponding commuting networks at different resolution scales, obtained from (i official census surveys, (ii proxy mobility data extracted from mobile phone call records, and (iii the radiation model calibrated with census data. Metapopulation models defined on these countries and integrating the different mobility layers are compared in terms of epidemic observables. We show that commuting networks from mobile phone data capture the empirical commuting patterns well, accounting for more than 87% of the total fluxes. The distributions of commuting fluxes per link from mobile phones and census sources are similar and highly correlated, however a systematic overestimation of commuting traffic in the mobile phone data is observed. This leads to epidemics that spread faster than on census commuting networks, once the mobile phone commuting network is considered in the epidemic model, however preserving to a high degree the order of infection of newly affected locations. Proxies' calibration affects the arrival times' agreement across different models, and the observed topological and traffic discrepancies among mobility sources alter the resulting epidemic invasion patterns. Results also suggest that proxies perform differently in approximating commuting patterns for disease spread at different resolution scales, with the radiation model showing higher accuracy than mobile phone data when the seed is central in the network, the opposite being observed for peripheral locations. Proxies

  20. On the use of human mobility proxies for modeling epidemics.

    Science.gov (United States)

    Tizzoni, Michele; Bajardi, Paolo; Decuyper, Adeline; Kon Kam King, Guillaume; Schneider, Christian M; Blondel, Vincent; Smoreda, Zbigniew; González, Marta C; Colizza, Vittoria

    2014-07-01

    Human mobility is a key component of large-scale spatial-transmission models of infectious diseases. Correctly modeling and quantifying human mobility is critical for improving epidemic control, but may be hindered by data incompleteness or unavailability. Here we explore the opportunity of using proxies for individual mobility to describe commuting flows and predict the diffusion of an influenza-like-illness epidemic. We consider three European countries and the corresponding commuting networks at different resolution scales, obtained from (i) official census surveys, (ii) proxy mobility data extracted from mobile phone call records, and (iii) the radiation model calibrated with census data. Metapopulation models defined on these countries and integrating the different mobility layers are compared in terms of epidemic observables. We show that commuting networks from mobile phone data capture the empirical commuting patterns well, accounting for more than 87% of the total fluxes. The distributions of commuting fluxes per link from mobile phones and census sources are similar and highly correlated, however a systematic overestimation of commuting traffic in the mobile phone data is observed. This leads to epidemics that spread faster than on census commuting networks, once the mobile phone commuting network is considered in the epidemic model, however preserving to a high degree the order of infection of newly affected locations. Proxies' calibration affects the arrival times' agreement across different models, and the observed topological and traffic discrepancies among mobility sources alter the resulting epidemic invasion patterns. Results also suggest that proxies perform differently in approximating commuting patterns for disease spread at different resolution scales, with the radiation model showing higher accuracy than mobile phone data when the seed is central in the network, the opposite being observed for peripheral locations. Proxies should therefore be

  1. 78 FR 70987 - Proxy Advisory Firm Roundtable

    Science.gov (United States)

    2013-11-27

    ... of proxy advisory firm use by investment advisers and institutional investors and potential changes... Special Counsel, Division of Investment Management, at 202-551-6700, or Raymond Be, Special Counsel...

  2. A serial Munchausen syndrome by proxy

    National Research Council Canada - National Science Library

    Esra Unal; Volkan Unal; Ali Gul; Mustafa Celtek; Behzat Diken; Ibrahim Balcioglu

    2017-01-01

    Munchausen syndrome by proxy (MSBP) is a form of child abuse that describes children whose parents or caregivers invent illness stories and substantiate the stories by fabricating false physical signs...

  3. Seizures and Munchausen Syndrome by Proxy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2002-05-01

    Full Text Available The prevalence, morbidity and mortality, diagnosis and management of cases of fabricated seizures and child abuse (Munchausen syndrome by proxy (MSbp are assessed by pediatricians at the University of Wales College of Medicine, Cardiff, UK.

  4. Munchausen Syndrome by Proxy: A Clinical Vignette

    Science.gov (United States)

    Zylstra, Robert G.; Miller, Karl E.; Stephens, Walter E.

    2000-01-01

    Munchausen syndrome by proxy is the act of one person fabricating or inducing an illness in another to meet his or her own emotional needs through the treatment process. The diagnosis is poorly understood and controversial. We report here the case of a 6-year-old boy who presented with possible pneumonia, nausea, vomiting, and diarrhea and whose mother was suspected of Munchausen syndrome by proxy. PMID:15014581

  5. PENGELOLAAN JARINGAN INTERNET DENGAN PROXY WINGATE

    Directory of Open Access Journals (Sweden)

    Titin Winarti

    2005-01-01

    Full Text Available Proxy adalah bagian dari protokol yang berfungsi sebagai link untuk host tunggal atau sebagai link untuk beberapa host antarajaringan dan jaringan lain. Proxy wingate adalah software yang digunakan untuk berbagi koneksi internet melalui satu alamat IPyang terintegrasi ke internet.

  6. Web proxy auto discovery for the WLCG

    CERN Document Server

    Dykstra, D; Blumenfeld, B; De Salvo, A; Dewhurst, A; Verguilov, V

    2017-01-01

    All four of the LHC experiments depend on web proxies (that is, squids) at each grid site to support software distribution by the CernVM FileSystem (CVMFS). CMS and ATLAS also use web proxies for conditions data distributed through the Frontier Distributed Database caching system. ATLAS & CMS each have their own methods for their grid jobs to find out which web proxies to use for Frontier at each site, and CVMFS has a third method. Those diverse methods limit usability and flexibility, particularly for opportunistic use cases, where an experiment’s jobs are run at sites that do not primarily support that experiment. This paper describes a new Worldwide LHC Computing Grid (WLCG) system for discovering the addresses of web proxies. The system is based on an internet standard called Web Proxy Auto Discovery (WPAD). WPAD is in turn based on another standard called Proxy Auto Configuration (PAC). Both the Frontier and CVMFS clients support this standard. The input into the WLCG system comes from squids regis...

  7. Health-related quality of life after stroke: reliability of proxy responses

    DEFF Research Database (Denmark)

    Muus, Ingrid; Petzold, Max; Ringsberg, Karin C

    2009-01-01

    A Danish version of the Stroke-Specific Quality of Life Scale (SSQOL-DK) has been developed for self-reporting; it contains 12 physical and psychosocial domains. The purpose of this study was (a) to assess the reliability of the proxy version of the SSQOL-DK and (b) to evaluate the influence...... of frequency of proxy contact on agreement. In all, 143 patients completed the SSQOL-DK 1 to 5 years post-stroke. A patient chosen proxy completed a proxy version of the same questionnaire. The proxy version showed satisfactory internal consistency (Cronbach's alpha = .85-.95). Agreement was generally high...... of the SSQOL-DK appears to be reliable for use with stroke patients up to a few years following a stroke....

  8. New indices and calibrations derived from the distribution of crenarchaeal isoprenoid tetraether lipids: Implications for past sea surface temperature reconstructions

    Science.gov (United States)

    Kim, Jung-Hyun; van der Meer, Jaap; Schouten, Stefan; Helmke, Peer; Willmott, Veronica; Sangiorgi, Francesca; Koç, Nalân; Hopmans, Ellen C.; Damsté, Jaap S. Sinninghe

    2010-08-01

    Several studies have shown that there is a strong relationship between the distribution of crenarchaeotal isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) and sea surface temperature (SST). Based on this, a ratio of certain GDGTs, called TEX 86 (TetraEther indeX of tetraethers consisting of 86 carbon atoms), was developed as a SST proxy. In this study, we determined the distribution of crenarchaeotal isoprenoid GDGTs in 116 core-top sediments mostly from (sub)polar oceans and combined these data with previously published core-top data. Using this extended global core-top dataset ( n = 426), we re-assessed the relationship of crenarchaeal isoprenoid GDGTs with SST. We excluded data from the Red Sea from the global core-top dataset to define new indices and calibration models, as the Red Sea with its elevated salinity appeared to behave differently compared to other parts of the oceans. We tested our new indices and calibration models on three different paleo datasets, representing different temperature ranges. Our results indicate that the crenarchaeol regio-isomer plays a more important role for temperature adaptation in (sub)tropical oceans than in (sub)polar oceans, suggesting that there may be differences in membrane adaptation of the resident crenarchaeotal communities at different temperatures. We, therefore, suggest to apply two different calibration models. For the whole calibration temperature range (-3 to 30 °C), a modified version of TEX 86 with a logarithmic function which does not include the crenarchaeol regio-isomer, called TEX86L, is shown to correlate best with SST: SST=67.5×TEX86L+46.9 ( r2 = 0.86, n=396, p <0.0001). Application of TEX86L on sediments from the subpolar Southern Ocean results in realistic absolute SST estimates and a similar SST trend compared to a diatom SST record from the same core. TEX86H, which is defined as the logarithmic function of TEX 86, yields the best correlation with SST, when the data from the (sub

  9. A 26 million year gap in the central Arctic record at the greenhouse-icehouse transition: Looking for clues

    Science.gov (United States)

    Sangiorgi, F.; Brumsack, H.-J.; Willard, D.A.; Schouten, S.; Stickley, C.E.; O'Regan, M.; Reichart, G.-J.; Sinninghe, Damste J.S.; Brinkhuis, H.

    2008-01-01

    The Cenozoic record of the Lomonosov Ridge (central Arctic Ocean) recovered during Integrated Ocean Drilling Program (IODP) Expedition 302 revealed an unexpected 26 Ma hiatus, separating middle Eocene (???44.4 Ma) from lower Miocene sediments (???18.2 Ma). To elucidate the nature of this unconformity, we performed a multiproxy palynological (dinoflagellate cysts, pollen, and spores), micropaleontological (siliceous microfossils), inorganic, and organic (Tetra Ether Index of lipids with 86 carbon atoms (TEX86) and Branched and Isoprenoid Tetraether (BIT)) geochemical analysis of the sediments from ???5 m below to ???7 m above the hiatus. Four main paleoenvironmental. phases (A-D) are recognized in the sediments encompassing the unconformity, two below (A-B) and two above (C-D): (A) Below the hiatus, proxies show relatively warm temperatures, with Sea Surface Temperatures (TEX86-derived SSTs) of about 8??C and high fresh to brackish water influence. (B) Approaching the hiatus, proxies indicate a cooling trend (TEX86-derived SSTs of ???5??C), increased freshwater influence, and progressive shoaling of the Lomonosov Ridge drilling site, located close to or at sea level. (C) The interval directly above the unconformity contains sparse reworked Cretaceous to Oligocene dinoflagellate cysts. Sediments were deposited in a relatively shallow, restricted marine environment. Proxies show the simultaneous influence of both fresh and marine waters, with alternating oxic and anoxic conditions. Pollen indicates a relatively cold climate. Intriguingly, TEX86-derived SSTs are unexpectedly high, ???15-19??C. Such warm surface waters may be partially explained by the ingression of warmer North Atlantic waters after the opening of the Fram Strait during the early Miocene. (D) Sediments of the uppermost interval indicate a phase of extreme oxic conditions, and a well-ventilated environment, which occurred after the complete opening of the Fram Strait. Importantly, and in contrast with

  10. Inferring climate variability from skewed proxy records

    Science.gov (United States)

    Emile-Geay, J.; Tingley, M.

    2013-12-01

    Many paleoclimate analyses assume a linear relationship between the proxy and the target climate variable, and that both the climate quantity and the errors follow normal distributions. An ever-increasing number of proxy records, however, are better modeled using distributions that are heavy-tailed, skewed, or otherwise non-normal, on account of the proxies reflecting non-normally distributed climate variables, or having non-linear relationships with a normally distributed climate variable. The analysis of such proxies requires a different set of tools, and this work serves as a cautionary tale on the danger of making conclusions about the underlying climate from applications of classic statistical procedures to heavily skewed proxy records. Inspired by runoff proxies, we consider an idealized proxy characterized by a nonlinear, thresholded relationship with climate, and describe three approaches to using such a record to infer past climate: (i) applying standard methods commonly used in the paleoclimate literature, without considering the non-linearities inherent to the proxy record; (ii) applying a power transform prior to using these standard methods; (iii) constructing a Bayesian model to invert the mechanistic relationship between the climate and the proxy. We find that neglecting the skewness in the proxy leads to erroneous conclusions and often exaggerates changes in climate variability between different time intervals. In contrast, an explicit treatment of the skewness, using either power transforms or a Bayesian inversion of the mechanistic model for the proxy, yields significantly better estimates of past climate variations. We apply these insights in two paleoclimate settings: (1) a classical sedimentary record from Laguna Pallcacocha, Ecuador (Moy et al., 2002). Our results agree with the qualitative aspects of previous analyses of this record, but quantitative departures are evident and hold implications for how such records are interpreted, and

  11. Law Enforcement Proxies Matter for the Law and Finance Nexus

    OpenAIRE

    Valentin Toci; Iraj Hashi

    2013-01-01

    The paper employs various measures of law enforcement to provide new evidence on the importance of legal institutions for different dimensions of financial development in transition economies. It offers a critical assessment of law enforcement measures employed in recent studies by showing that some proxies for law enforcement in the credit market may not be appropriate. Hence, care should be taken in how the quality of institutions is measured and the context which it represents. An original...

  12. Cooperative Proxy Caching for Wireless Base Stations

    Directory of Open Access Journals (Sweden)

    James Z. Wang

    2007-01-01

    Full Text Available This paper proposes a mobile cache model to facilitate the cooperative proxy caching in wireless base stations. This mobile cache model uses a network cache line to record the caching state information about a web document for effective data search and cache space management. Based on the proposed mobile cache model, a P2P cooperative proxy caching scheme is proposed to use a self-configured and self-managed virtual proxy graph (VPG, independent of the underlying wireless network structure and adaptive to the network and geographic environment changes, to achieve efficient data search, data cache and date replication. Based on demand, the aggregate effect of data caching, searching and replicating actions by individual proxy servers automatically migrates the cached web documents closer to the interested clients. In addition, a cache line migration (CLM strategy is proposed to flow and replicate the heads of network cache lines of web documents associated with a moving mobile host to the new base station during the mobile host handoff. These replicated cache line heads provide direct links to the cached web documents accessed by the moving mobile hosts in the previous base station, thus improving the mobile web caching performance. Performance studies have shown that the proposed P2P cooperative proxy caching schemes significantly outperform existing caching schemes.

  13. How different proxies record precipitation variability over southeastern South America

    Energy Technology Data Exchange (ETDEWEB)

    Chiessi, Cristiano M; Mulitza, Stefan; Paetzold, Juergen; Wefer, Gerold, E-mail: chiessi@uni-bremen.d [MARUM-Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, 28359 Bremen (Germany)

    2010-03-15

    Detrending natural and anthropogenic components of climate variability is arguably an issue of utmost importance to society. To accomplish this issue, one must rely on a comprehensive understanding of the natural variability of the climate system on a regional level. Here we explore how different proxies (e.g., stalagmite oxygen isotopic composition, pollen percentages, bulk sediment elemental ratios) record Holocene precipitation variability over southeastern South America. We found a general good agreement between the different records both on orbital and centennial time-scales. Dry mid Holocene, and wet late Holocene, Younger Dryas and a period between {approx}9.4 and 8.12 cal kyr BP seem to be pervasive features. Moreover, we show that proxy-specific sensitivity can greatly improve past precipitation reconstructions.

  14. A statistical proxy for sulphuric acid concentration

    Directory of Open Access Journals (Sweden)

    S. Mikkonen

    2011-11-01

    Full Text Available Gaseous sulphuric acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of sulphuric acid. This study evaluates a body of experimental gas phase sulphuric acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiälä, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies" for sulphuric acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the sulphuric acid concentration proxy uses global solar radiation, SO2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure (R of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO2 concentration alone. This could be attributed to SO2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of sulphuric acid.

  15. Marine proxy evidence linking decadal North Pacific and Atlantic climate

    Energy Technology Data Exchange (ETDEWEB)

    Hetzinger, S. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); Halfar, J. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Mecking, J.V.; Keenlyside, N.S. [Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research, Bergen (Norway); Kronz, A. [University of Goettingen, Geowissenschaftliches Zentrum, Goettingen (Germany); Steneck, R.S. [University of Maine, Darling Marine Center, Walpole, ME (United States); Adey, W.H. [Smithsonian Institution, Department of Botany, Washington, DC (United States); Lebednik, P.A. [ARCADIS U.S. Inc., Walnut Creek, CA (United States)

    2012-09-15

    Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818-1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. (orig.)

  16. Web Proxy Auto Discovery for the WLCG

    Science.gov (United States)

    Dykstra, D.; Blomer, J.; Blumenfeld, B.; De Salvo, A.; Dewhurst, A.; Verguilov, V.

    2017-10-01

    All four of the LHC experiments depend on web proxies (that is, squids) at each grid site to support software distribution by the CernVM FileSystem (CVMFS). CMS and ATLAS also use web proxies for conditions data distributed through the Frontier Distributed Database caching system. ATLAS & CMS each have their own methods for their grid jobs to find out which web proxies to use for Frontier at each site, and CVMFS has a third method. Those diverse methods limit usability and flexibility, particularly for opportunistic use cases, where an experiment’s jobs are run at sites that do not primarily support that experiment. This paper describes a new Worldwide LHC Computing Grid (WLCG) system for discovering the addresses of web proxies. The system is based on an internet standard called Web Proxy Auto Discovery (WPAD). WPAD is in turn based on another standard called Proxy Auto Configuration (PAC). Both the Frontier and CVMFS clients support this standard. The input into the WLCG system comes from squids registered in the ATLAS Grid Information System (AGIS) and CMS SITECONF files, cross-checked with squids registered by sites in the Grid Configuration Database (GOCDB) and the OSG Information Management (OIM) system, and combined with some exceptions manually configured by people from ATLAS and CMS who operate WLCG Squid monitoring. WPAD servers at CERN respond to http requests from grid nodes all over the world with a PAC file that lists available web proxies, based on IP addresses matched from a database that contains the IP address ranges registered to organizations. Large grid sites are encouraged to supply their own WPAD web servers for more flexibility, to avoid being affected by short term long distance network outages, and to offload the WLCG WPAD servers at CERN. The CERN WPAD servers additionally support requests from jobs running at non-grid sites (particularly for LHC@Home) which they direct to the nearest publicly accessible web proxy servers. The responses

  17. Holocene Temperature Record of the North Antarctic Peninsula

    Science.gov (United States)

    Willmott, V.; Kim, J.; Domack, E. W.; Sinninghe Damsté, J. S.; Schouten, S.

    2009-12-01

    Because sea temperature plays a critical role not only on the stability of ice shelves and sea ice formation, but as well on the marine ecology of polar areas, a lot of effort has been placed to reconstruct the past climate using proxies from ice, marine and terrestrial records. However, it has been difficult to apply traditional paleoenvironmental proxies in polar areas because of problems that include insufficient dating of recovered sequences, complexities introduced by glacial activity (i.e. glacial erosion), sea-ice cover and poor calcium carbonate preservation. Despite these difficulties, some paleoenvironmental records have been obtained so far although paleotemperature records are still very scarce. The TEX86 (TetraEther indeX of lipids with 86 carbon atoms), is an organic-based paleothermomether (Schouten et al., 2002) based on the relative distribution of archaeal lipids (GDGTs) biosynthesized by marine Crenarchaeota, one of the main prokaryotes of today’s oceans. Although the use of TEX86 in polar areas may be promising because it can be measured in carbonate poor sediments, its global correlation with sea surface temperature (SST) (Kim et al., 2008) revealed that the relationship between TEX86 values and SSTs over the entire temperature range was non-linear, mainly because below 5°C, i.e. in the polar oceans, changes in TEX86 were relatively minor with temperature. Recently, we obtained new insights on the relation between isoprenoid GDGTs and SST in polar oceans using an extended core-top sediment dataset which has lead to a new GDGT index which minimizes the scatter at low temperatures. We applied this new index to obtain a detailed Holocene SST record from well dated sediment cores from the north western Antarctic Peninsula. Temperature ranges show absolute temperature estimates (between -1 and 6 °C) in agreement with present day temperature range, reaching warmer temperatures between 6 to 8 ky. Cooler temperatures of about 2 °C dominates the

  18. Shell architecture: a novel proxy for paleotemperature reconstructions?

    Science.gov (United States)

    Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Witbaard, Rob; Schöne, Bernd R.

    2017-04-01

    Mollusk shells are unique high-resolution paleoenvironmental archives. Their geochemical properties, such as oxygen isotope composition (δ18Oshell) and element-to-calcium ratios, are routinely used to estimate past environmental conditions. However, the existing proxies have certain drawbacks that can affect paleoreconstruction robustness. For instance, the estimation of water temperature of brackish and near-shore environments can be biased by the interdependency of δ18Oshell from multiple environmental variables (water temperature and δ18Owater). Likely, the environmental signature can be masked by physiological processes responsible for the incorporation of trace elements into the shell. The present study evaluated the use of shell structural properties as alternative environmental proxies. The sensitivity of shell architecture at µm and nm-scale to the environment was tested. In particular, the relationship between water temperature and microstructure formation was investigated. To enable the detection of potential structural changes, the shells of the marine bivalves Cerastoderma edule and Arctica islandica were analyzed with Scanning Electron Microscopy (SEM), nanoindentation and Confocal Raman Microscopy (CRM). These techniques allow a quantitative approach to the microstructural analysis. Our results show that water temperature induces a clear response in shell microstructure. A significant alteration in the morphometric characteristics and crystallographic orientation of the structural units was observed. Our pilot study suggests that shell architecture records environmental information and it has potential to be used as novel temperature proxy in near-shore and open ocean habitats.

  19. Heinrich event 4 characterized by terrestrial proxies in southwestern Europe

    Directory of Open Access Journals (Sweden)

    J. M. López-García

    2013-05-01

    Full Text Available Heinrich event 4 (H4 is well documented in the North Atlantic Ocean as a cooling event that occurred between 39 and 40 Ka. Deep-sea cores around the Iberian Peninsula coastline have been analysed to characterize the H4 event, but there are no data on the terrestrial response to this event. Here we present for the first time an analysis of terrestrial proxies for characterizing the H4 event, using the small-vertebrate assemblage (comprising small mammals, squamates and amphibians from Terrassa Riera dels Canyars, an archaeo-palaeontological deposit located on the seaboard of the northeastern Iberian Peninsula. This assemblage shows that the H4 event is characterized in northeastern Iberia by harsher and drier terrestrial conditions than today. Our results were compared with other proxies such as pollen, charcoal, phytolith, avifauna and large-mammal data available for this site, as well as with the general H4 event fluctuations and with other sites where H4 and the previous and subsequent Heinrich events (H5 and H3 have been detected in the Mediterranean and Atlantic regions of the Iberian Peninsula. We conclude that the terrestrial proxies follow the same patterns as the climatic and environmental conditions detected by the deep-sea cores at the Iberian margins.

  20. Munchausen Syndrome by Proxy: Medical Diagnostic Criteria.

    Science.gov (United States)

    Rosenberg, Donna Andrea

    2003-01-01

    Medical diagnostic criteria for Munchausen Syndrome by Proxy (a persistent fabrication by one individual of illness in another) are presented. Since the strength of the known facts may vary from case to case, diagnostic criteria are given for a definitive diagnosis, a possible diagnosis, an inconclusive determination, and the definitely excluded…

  1. Munchausen Syndrome by Proxy: Evaluation and Treatment.

    Science.gov (United States)

    Parnell, Teresa F.; Day, Deborah O.

    Munchausen Syndrome by Proxy (MSBP) is characterized by a significant caretaker, usually a mother, deliberately inducing and/or falsely reporting illness in a child. The potentially fatal outcome of undetected MSBP makes the understanding of this syndrome gravely important. Early detection and effective intervention can be accomplished through the…

  2. Munchausen Syndrome by Proxy: Social Work's Role.

    Science.gov (United States)

    Mercer, Susan O.; Perdue, Jeanette D.

    1993-01-01

    Describes Munchausen syndrome by proxy, diagnosis used to describe variation of child abuse whereby parent or adult caregiver fabricates medical history or induces symptoms in child, or both, resulting in unnecessary examinations, treatments, hospitalizations, and even death. Reviews assessment procedures, provides case studies, and describes…

  3. Munchausen Syndrome by Proxy: A Family Affair.

    Science.gov (United States)

    Mehl, Albert L.; And Others

    1990-01-01

    The article reports on a case of Munchausen syndrome by proxy in which chronic illicit insulin was administered to a one-year-old child by her mother. Factitious illnesses continued despite psychiatric intervention. Retrospective review of medical records suggested 30 previous episodes of factitious illness within the family. (DB)

  4. The Syndrome of Munchausen by Proxy.

    Science.gov (United States)

    Jones, David P. H.

    1994-01-01

    This editorial introduces two articles on Munchausen by Proxy syndrome (the induction of an appearance or state of physical ill health in a child, by the caretaker, and the child's subsequent presentation to health professionals for diagnosis and/or treatment). The severity of the caretaker's psychological disturbance and the serious effects on…

  5. Improving Internet Archive Service through Proxy Cache.

    Science.gov (United States)

    Yu, Hsiang-Fu; Chen, Yi-Ming; Wang, Shih-Yong; Tseng, Li-Ming

    2003-01-01

    Discusses file transfer protocol (FTP) servers for downloading archives (files with particular file extensions), and the change to HTTP (Hypertext transfer protocol) with increased Web use. Topics include the Archie server; proxy cache servers; and how to improve the hit rate of archives by a combination of caching and better searching mechanisms.…

  6. Using Resin-Based 3D Printing to Build Geometrically Accurate Proxies of Porous Sedimentary Rocks.

    Science.gov (United States)

    Ishutov, Sergey; Hasiuk, Franciszek J; Jobe, Dawn; Agar, Susan

    2017-09-28

    Three-dimensional (3D) printing is capable of transforming intricate digital models into tangible objects, allowing geoscientists to replicate the geometry of 3D pore networks of sedimentary rocks. We provide a refined method for building scalable pore-network models ("proxies") using stereolithography 3D printing that can be used in repeated flow experiments (e.g., core flooding, permeametry, porosimetry). Typically, this workflow involves two steps, model design and 3D printing. In this study, we explore how the addition of post-processing and validation can reduce uncertainty in the 3D-printed proxy accuracy (difference of proxy geometry from the digital model). Post-processing is a multi-step cleaning of porous proxies involving pressurized ethanol flushing and oven drying. Proxies are validated by: (1) helium porosimetry and (2) digital measurements of porosity from thin-section images of 3D-printed proxies. 3D printer resolution was determined by measuring the smallest open channel in 3D-printed "gap test" wafers. This resolution (400 µm) was insufficient to build porosity of Fontainebleau sandstone (∼13%) from computed tomography data at the sample's natural scale, so proxies were printed at 15-, 23-, and 30-fold magnifications to validate the workflow. Helium porosities of the 3D-printed proxies differed from digital calculations by up to 7% points. Results improved after pressurized flushing with ethanol (e.g., porosity difference reduced to ∼1% point), though uncertainties remain regarding the nature of sub-micron "artifact" pores imparted by the 3D printing process. This study shows the benefits of including post-processing and validation in any workflow to produce porous rock proxies. © 2017, National Ground Water Association.

  7. A Quantum Proxy Blind Signature Scheme Based on Genuine Five-Qubit Entangled State

    Science.gov (United States)

    Zeng, Chuan; Zhang, Jian-Zhong; Xie, Shu-Cui

    2017-06-01

    In this paper, a quantum proxy blind signature scheme based on controlled quantum teleportation is proposed. This scheme uses a genuine five-qubit entangled state as quantum channel and adopts the classical Vernam algorithm to blind message. We use the physical characteristics of quantum mechanics to implement delegation, signature and verification. Security analysis shows that our scheme is valid and satisfy the properties of a proxy blind signature, such as blindness, verifiability, unforgeability, undeniability.

  8. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Science.gov (United States)

    Pyrina, Maria; Wagner, Sebastian; Zorita, Eduardo

    2017-10-01

    Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs) of the North Atlantic (NA) Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE) setup using state-of-the-art climate models (CMIP5 Earth system models) and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR) are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica islandica can

  9. Pseudo-proxy evaluation of climate field reconstruction methods of North Atlantic climate based on an annually resolved marine proxy network

    Directory of Open Access Journals (Sweden)

    M. Pyrina

    2017-10-01

    Full Text Available Two statistical methods are tested to reconstruct the interannual variations in past sea surface temperatures (SSTs of the North Atlantic (NA Ocean over the past millennium based on annually resolved and absolutely dated marine proxy records of the bivalve mollusk Arctica islandica. The methods are tested in a pseudo-proxy experiment (PPE setup using state-of-the-art climate models (CMIP5 Earth system models and reanalysis data from the COBE2 SST data set. The methods were applied in the virtual reality provided by global climate simulations and reanalysis data to reconstruct the past NA SSTs using pseudo-proxy records that mimic the statistical characteristics and network of Arctica islandica. The multivariate linear regression methods evaluated here are principal component regression and canonical correlation analysis. Differences in the skill of the climate field reconstruction (CFR are assessed according to different calibration periods and different proxy locations within the NA basin. The choice of the climate model used as a surrogate reality in the PPE has a more profound effect on the CFR skill than the calibration period and the statistical reconstruction method. The differences between the two methods are clearer for the MPI-ESM model due to its higher spatial resolution in the NA basin. The pseudo-proxy results of the CCSM4 model are closer to the pseudo-proxy results based on the reanalysis data set COBE2. Conducting PPEs using noise-contaminated pseudo-proxies instead of noise-free pseudo-proxies is important for the evaluation of the methods, as more spatial differences in the reconstruction skill are revealed. Both methods are appropriate for the reconstruction of the temporal evolution of the NA SSTs, even though they lead to a great loss of variance away from the proxy sites. Under reasonable assumptions about the characteristics of the non-climate noise in the proxy records, our results show that the marine network of Arctica

  10. A biomarker perspective on dust, productivity, and sea surface temperature in the Pacific sector of the Southern Ocean

    Science.gov (United States)

    Jaeschke, Andrea; Wengler, Marc; Hefter, Jens; Ronge, Thomas A.; Geibert, Walter; Mollenhauer, Gesine; Gersonde, Rainer; Lamy, Frank

    2017-05-01

    In this study, we present a new multiproxy data set of terrigenous input, marine productivity and sea surface temperature (SST) from 52 surface sediment samples collected along E-W transects in the Pacific sector of the Southern Ocean. Allochthonous terrigenous input was characterized by the distribution of plant wax n-alkanes and soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs). 230Th-normalized burial of both compound groups were highest close to the potential sources in Australia and New Zealand and are strongly related to lithogenic contents (232Th), indicating common sources and transport. Detection of both long-chain n-alkanes and brGDGTs at the most remote sites in the open ocean strongly suggests a primarily eolian transport mechanism to at least 110°W, i.e. by prevailing westerly winds. Two independent organic SST proxies were used, the U37K‧ based on alkenones, and the TEX86 based on isoprenoid GDGTs. Both, U37K‧ and TEX86 indices show robust relationships with temperature over a temperature range between 0.5 and 20 °C, likely implying different seasonal and regional imprints on the temperature signal. Alkenone-based temperature estimates best reflect modern summer SST in the study area when using the polar calibration of Sikes et al. (1997). In contrast, TEX86-derived temperatures may reflect a subsurface signal rather than surface. 230Th-normalized burial of alkenones is highest close to the Subtropical Front and is positively related to the deposition of lithogenic material throughout the study area. In contrast, highest isoGDGT burial south of the Antarctic Polar Front may be largely controlled by diatom blooms, and thus high opal fluxes during austral summer.

  11. Millennial-scale sea surface temperature changes in the eastern Mediterranean (Nile River Delta region) over the last 27,000 years

    Science.gov (United States)

    Castañeda, Isla S.; Schefuß, Enno; Pätzold, Jürgen; Sinninghe Damsté, Jaap S.; Weldeab, Syee; Schouten, Stefan

    2010-03-01

    In this study we utilize two organic geochemical proxies, the U37k‧ index and TEX86, to examine past sea surface temperatures (SST) from a site located near the Nile River Delta in the eastern Mediterranean (EM) Sea. The U37k‧ and TEX86 records generally are in agreement and indicate SST ranges of 14°C-26°C and 14°C-28°C, respectively, during the last 27 cal ka. During the Holocene, TEX86-based SST estimates are usually higher than U37k‧-based SST estimates, which is likely due to seasonal differences between the timing of the haptophyte and crenarchaeota blooms in the EM and is related to the onset of the modern flow regime of the Nile River. Both records show that SST varied on centennial to millennial timescales in response to global climate events, i.e., cooling during the Last Glacial Maximum (LGM), Heinrich event 1 (H1), and the Younger Dryas (YD) and warming during the Bølling-Allerød and in the early Holocene during deposition of sapropel S1. The H1 cooling was particularly severe and is marked by a drop in SST of ˜4.5°C in comparison to pre-H1 SST, with temperatures >1°C cooler than during the LGM. In contrast to high-latitude and western Mediterranean records, which indicate both an abrupt onset and termination of the YD event, the transition from the YD to the Holocene was much more gradual in the EM.

  12. Legal requirements governing proxy voting in Denmark

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2008-01-01

    The requirements in Danish company law concerning proxy voting in companies whose shares have been accepted for listing on a regulated market have been successively tightened in recent years, and corporate governance principles have also led to the introduction of several requirements concerning...... proxy holders. A thorough knowledge of these requirements is important not only for the listed companies but also for their advisers and investors in Denmark and abroad. This article considers these requirements as well as the additional requirements which will derive from Directive 2007....../36 on the exercise of shareholders' rights in listed companies, which must be implemented by 3 August 2009. It is pointed out that companies may provide with advantage in their articles of association for both the existing and the forthcoming requirements at this early stage....

  13. Observable Proxies For 26 Al Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Christopher L [Los Alamos National Laboratory; Young, Patrick A [Los Alamos National Laboratory; Ellinger, Carola I [ASU; Arnett, William D [UNIV ARIZONA

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  14. Non-destructive foraminiferal paleoclimatic proxies: A brief insight

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.

    Non-Destructive Foraminiferal Paleoclimatic Proxies: A Brief Insight The knowledge of past climate can help us to understand imminent climatic changes. Oceans are the vast archives of past climate. Various indirect techniques termed as proxies...

  15. Implementasi Proxy Server Dengan Linux Clear OS 5.2

    OpenAIRE

    Setiadi, Aprian

    2013-01-01

    Tugas Akhir ini membahas mengenai cara untuk membangun sebuah proxy server dalam jaringan LAN. Jaringan LAN yang dibangun menggunakan arsitektur topologi star dengan menjadikan komputer server sebagai Gateway Server dan Proxy Server, sehingga tidak membutuhkan perangkat tambahan Router yang berfungsi sebagai Gateway Server. Proxy Server yang yang dibangun menggunakan metode Transparent Mode, sehingga pada komputer klien tidak perlu mengkonfigurasi port proxy server pada Web Browser. Hasil ya...

  16. 12 CFR 7.2002 - Director or attorney as proxy.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Director or attorney as proxy. 7.2002 Section 7... OPERATIONS Corporate Practices § 7.2002 Director or attorney as proxy. Any person or group of persons, except the bank's officers, clerks, tellers, or bookkeepers, may be designated to act as proxy. The bank's...

  17. Physicians' Involvement with the New York State Health Care Proxy

    Science.gov (United States)

    Heyman, Janna C.; Sealy, Yvette M.

    2011-01-01

    This study examined physicians' attitude, involvement, and perceived barriers with the health care proxy. A cross sectional, correlational design was used to survey practicing physicians (N = 70). Physicians had positive attitudes toward the health care proxy and indicated that the most significant barriers to health care proxy completion were…

  18. A method of separating local and large scale climate signals in coral proxies

    Science.gov (United States)

    Timm, O.; Ruprecht, E.; Pfeiffer, M.; Dullo, W.

    2003-04-01

    Coral proxies in the tropical and subtropical Indian Ocean show markedly different imprints of local climate factors. The oxygen isotopic composition (d18o) reflects a combination of SST and seawater properties. Both are the response to local effects and large scale climate variations in the oceans and the atmosphere, mainly due to air-sea fluxes. Consequently, an important step to large scale climate reconstructions from coral proxies is the separation of the individual local signal and the teleconnection with large scale climate modes such as the El Nino/Southern Oscillation (ENSO). The aim of this study is to present a method capable of extracting the large scale climate signal recorded in corals. Using multiple linear regression (MLR) techniques we first analyse the partial effects of local SST and precipitation minus evaporation on the coral d18o proxies. In a second step multivariate statistics are applied to the proxies and climate variables in order to distinguish between local signals and large scale variability in the proxies. Three d18o records from the Indian Ocean (Chagos, La Reunion, Seychelles) and the ENSO signal are used as an example demonstration. The method is also applied to Carribean corals (Guadeloupe). Preliminary results for the variability of these proxies and their relation to the North Atlantic Oscillation are given.

  19. Technical Note: Probabilistically constraining proxy age–depth models within a Bayesian hierarchical reconstruction model

    Directory of Open Access Journals (Sweden)

    J. P. Werner

    2015-03-01

    Full Text Available Reconstructions of the late-Holocene climate rely heavily upon proxies that are assumed to be accurately dated by layer counting, such as measurements of tree rings, ice cores, and varved lake sediments. Considerable advances could be achieved if time-uncertain proxies were able to be included within these multiproxy reconstructions, and if time uncertainties were recognized and correctly modeled for proxies commonly treated as free of age model errors. Current approaches for accounting for time uncertainty are generally limited to repeating the reconstruction using each one of an ensemble of age models, thereby inflating the final estimated uncertainty – in effect, each possible age model is given equal weighting. Uncertainties can be reduced by exploiting the inferred space–time covariance structure of the climate to re-weight the possible age models. Here, we demonstrate how Bayesian hierarchical climate reconstruction models can be augmented to account for time-uncertain proxies. Critically, although a priori all age models are given equal probability of being correct, the probabilities associated with the age models are formally updated within the Bayesian framework, thereby reducing uncertainties. Numerical experiments show that updating the age model probabilities decreases uncertainty in the resulting reconstructions, as compared with the current de facto standard of sampling over all age models, provided there is sufficient information from other data sources in the spatial region of the time-uncertain proxy. This approach can readily be generalized to non-layer-counted proxies, such as those derived from marine sediments.

  20. Proxy Graph: Visual Quality Metrics of Big Graph Sampling.

    Science.gov (United States)

    Nguyen, Quan Hoang; Hong, Seok-Hee; Eades, Peter; Meidiana, Amyra

    2017-06-01

    Data sampling has been extensively studied for large scale graph mining. Many analyses and tasks become more efficient when performed on graph samples of much smaller size. The use of proxy objects is common in software engineering for analysis and interaction with heavy objects or systems. In this paper, we coin the term 'proxy graph' and empirically investigate how well a proxy graph visualization can represent a big graph. Our investigation focuses on proxy graphs obtained by sampling; this is one of the most common proxy approaches. Despite the plethora of data sampling studies, this is the first evaluation of sampling in the context of graph visualization. For an objective evaluation, we propose a new family of quality metrics for visual quality of proxy graphs. Our experiments cover popular sampling techniques. Our experimental results lead to guidelines for using sampling-based proxy graphs in visualization.

  1. Solar spectral irradiance datasets: analysis and comparison with proxies

    Science.gov (United States)

    Kretzschmar, M.; Schoell, M.; Dudok de Wit, T.

    2013-12-01

    Solar spectral irradiance (SSI) measurements have been acquired in space since the late 1960's. These data are of extreme importance to assess the variability of the Sun in the last decades as well as to understand how its magnetic activity affects its radiative output, and therefore to constrain the solar variability further in time. However, these data sometimes disagree between themselves or with our expectations deduced from well known observed proxies, and it is hard to disentangle instrumental effects from possible solar behavior. In the context of the european project SOLID (First European comprehensive SOlar Irradiance Data Exploitation) project, which aims at building an SSI composite with time dependent error-bars over the space age, we will show our first results towards the construction of a carefully assessed homogeneous solar spectral irradiance datasets, focussing on the ultraviolet wavelength range, for which more data are available. We will first present the data used, together with methods for gap-filling and outlier removal. Then we will show some results obtained by comparing a single dataset at different times of the mission, as well as results obtained from the comparison of simultaneous datasets and proxies. Finally, we will discuss how these analyses can help us to estimate errors on the solar variability at a particular wavelength.

  2. Adaptability in CORBA: The Mobile Proxy Approach

    DEFF Research Database (Denmark)

    Aziz, B.; Jensen, Christian D.

    2000-01-01

    are inherently open, heterogeneous, and dynamic environments integrating a wide range of platforms, operating systems and applications from a number of different sources. In this paper, we propose to use mobile proxies to provide adaptability in distributed applications integrated using the CORBA technology......Adaptability is one of the most important challenges in modern distributed systems. It may be defined as the ease with which a software application satisfies the different system constraints and the requirements of users and other applications. Adaptability is needed because distributed systems...

  3. Munchausen syndrome by proxy: ongoing clinical challenges.

    Science.gov (United States)

    Squires, Janet E; Squires, Robert H

    2010-09-01

    In 1977, Roy Meadow, a pediatric nephrologist, first described a condition he subsequently coined Munchausen syndrome by proxy. The classic form involves a parent or other caregiver who inflicts injury or induces illness in a child, deceive the treating physician with fictitious or exaggerated information, and perpetrate the trick for months or years. A related form of pathology is more insidious and more common but also damaging. It involves parents who fabricate or exaggerate symptoms of illness in children, causing overly aggressive medical evaluations and interventions. The common thread is that the treating physician plays a role in inflicting the abuse upon the child. Failure to recognize the problem is common because the condition is often not included in the differential diagnosis of challenging or confusing clinical problems. We believe that a heightened "self-awareness" of the physician's role in Munchausen syndrome by proxy will prevent or reduce the morbidity and mortality associated with this diagnosis. In addition, we believe contemporary developments within the modern health care system likely facilitate this condition.

  4. A biomarker record of temperature and phytoplankton community in Okinawa Trough since the last glacial maximum

    Science.gov (United States)

    Ruan, Jiaping

    2017-04-01

    A variety of biomarkers were examined from Ocean Drilling Program (ODP) core 1202B to reconstruct temperature and phytoplankton community structures in the southern Okinawa Trough for the past ca. 20000 years. Two molecular temperature proxies (Uk37 and TEX86) show 5-6 ℃ warming during the glacial/interglacial transition. Prior to the Holocene, the Uk37-derived temperature was generally 1-4 ℃ higher than TEX86-derived temperature. This difference, however, was reduced to phytoplankton biomarkers (e.g., C37:2 alkenone, brassicasterol, C30 1,15-diols and dinosterol) suggest a shift of planktonic community assemblages with coccolithophorids becoming more abundant in the Holocene at the expense of diatoms/dinoflagellates. Such a shift is related to the variability of nutrient, temperature and salinity in the Okinawa Trough, controlled by the sea level and the intensity of Kuroshio Current. The phytoplankton community change may have profound implications on atmospheric CO2 fluctuations during glacial/interglacial cycles since diatoms and dinoflagellates have a higher efficiency of biological pump than coccolithophorids.

  5. Care for Sick Children as a Proxy for Gender Equality in the Family

    Science.gov (United States)

    Eriksson, Rickard; Nermo, Magnus

    2010-01-01

    Swedish parents are entitled to government paid benefits to take care of sick children. In this paper we show that the gender distribution of paid care for sick children is a good proxy for the gender division of household work. Using two examples we show that registry data on care for sick children is a useful data source for studies on gender…

  6. Self and proxy rating of quality of life in adults with intellectual disabilities: results from the DISQOL study.

    Science.gov (United States)

    Schmidt, Silke; Power, Mick; Green, Ann; Lucas-Carrasco, Ramona; Eser, Erhan; Dragomirecka, Eva; Fleck, Marcello

    2010-01-01

    The aim of this study was to analyze the agreement between self and proxy reports of quality of life (QoL) in people with intellectual disabilities and to examine the factors which contribute to these differences. The study was conducted across six international centres in a sample of 614 adults with intellectual disabilities as well as two different samples of proxies (N=874) including both professional carers and relatives. QoL was assessed with the disability version of the WHOQOL-BREF. In both proxy samples results show a significant moderate association between the persons' QoL-assessment and the assessment of their proxies in all of the five QoL domains. There were significant mean differences in most items which varied in their direction. In general, people with disabilities rated their QoL higher than their proxies except for two items from the physical domain. The factors which most significantly contributed to these differences were proxy knowledge of the person as well as the WHODAS-disability score. Cross-cultural differences in the magnitude of concordance were observed. As a conclusion, the study shows a good agreement between the person-proxy QoL-assessments, and that the factors associated with disagreement are limited in this study. Future studies should elaborate the stability of concordance over time. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  7. Production and preservation of archaeal glycerol dibiphytanyl glycerol tetraethers as intact polar lipids in marine sediments: Implications for their use in microbial ecology and TEX86 paleothermometry

    NARCIS (Netherlands)

    Lengger, S.K.

    2013-01-01

    For climate modelling in order to predict climate change scenarios, it is important to consider past climate conditions and their impacts. The study of past climates, paleoclimatology, makes frequent use of molecular fossils, molecules that are preserved over geological time scales. Ratios of

  8. Workflows for intelligent monitoring using proxy services.

    Science.gov (United States)

    Rüping, Stefan; Wegener, Dennis; Sfakianakis, Stelios; Sengstag, Thierry

    2009-01-01

    Grid technologies have proven to be very successful in the area of eScience, and in particular in healthcare applications. But while the applicability of workflow enacting tools for biomedical research has long since been proven, the practical adoption into regular clinical research has some additional challenges in grid context. In this paper, we investigate the case of data monitoring, and how to seamlessly implement the step between a one-time proof-of-concept workflow and high-performance on-line monitoring of data streams, as exemplified by the case of long-running clinical trials. We will present an approach based on proxy services that allows executing single-run workflows repeatedly with little overhead.

  9. Salmon: Robust Proxy Distribution for Censorship Circumvention

    Directory of Open Access Journals (Sweden)

    Douglas Frederick

    2016-10-01

    Full Text Available Many governments block their citizens’ access to much of the Internet. Simple workarounds are unreliable; censors quickly discover and patch them. Previously proposed robust approaches either have non-trivial obstacles to deployment, or rely on low-performance covert channels that cannot support typical Internet usage such as streaming video. We present Salmon, an incrementally deployable system designed to resist a censor with the resources of the “Great Firewall” of China. Salmon relies on a network of volunteers in uncensored countries to run proxy servers. Although any member of the public can become a user, Salmon protects the bulk of its servers from being discovered and blocked by the censor via an algorithm for quickly identifying malicious users. The algorithm entails identifying some users as especially trustworthy or suspicious, based on their actions. We impede Sybil attacks by requiring either an unobtrusive check of a social network account, or a referral from a trustworthy user.

  10. Development of six PROMIS pediatrics proxy-report item banks

    Directory of Open Access Journals (Sweden)

    Irwin Debra E

    2012-02-01

    Full Text Available Abstract Background Pediatric self-report should be considered the standard for measuring patient reported outcomes (PRO among children. However, circumstances exist when the child is too young, cognitively impaired, or too ill to complete a PRO instrument and a proxy-report is needed. This paper describes the development process including the proxy cognitive interviews and large-field-test survey methods and sample characteristics employed to produce item parameters for the Patient Reported Outcomes Measurement Information System (PROMIS pediatric proxy-report item banks. Methods The PROMIS pediatric self-report items were converted into proxy-report items before undergoing cognitive interviews. These items covered six domains (physical function, emotional distress, social peer relationships, fatigue, pain interference, and asthma impact. Caregivers (n = 25 of children ages of 5 and 17 years provided qualitative feedback on proxy-report items to assess any major issues with these items. From May 2008 to March 2009, the large-scale survey enrolled children ages 8-17 years to complete the self-report version and caregivers to complete the proxy-report version of the survey (n = 1548 dyads. Caregivers of children ages 5 to 7 years completed the proxy report survey (n = 432. In addition, caregivers completed other proxy instruments, PedsQL™ 4.0 Generic Core Scales Parent Proxy-Report version, PedsQL™ Asthma Module Parent Proxy-Report version, and KIDSCREEN Parent-Proxy-52. Results Item content was well understood by proxies and did not require item revisions but some proxies clearly noted that determining an answer on behalf of their child was difficult for some items. Dyads and caregivers of children ages 5-17 years old were enrolled in the large-scale testing. The majority were female (85%, married (70%, Caucasian (64% and had at least a high school education (94%. Approximately 50% had children with a chronic health condition, primarily

  11. A Quantum Multi-Proxy Weak Blind Signature Scheme Based on Entanglement Swapping

    Science.gov (United States)

    Yan, LiLi; Chang, Yan; Zhang, ShiBin; Han, GuiHua; Sheng, ZhiWei

    2017-02-01

    In this paper, we present a multi-proxy weak blind signature scheme based on quantum entanglement swapping of Bell states. In the scheme, proxy signers can finish the signature instead of original singer with his/her authority. It can be applied to the electronic voting system, electronic paying system, etc. The scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. It could guarantee not only the unconditionally security but also the anonymity of the message owner. The security analysis shows the scheme satisfies the security features of multi-proxy weak signature, singers cannot disavowal his/her signature while the signature cannot be forged by others, and the message owner can be traced.

  12. Law Enforcement Proxies Matter for the Law and Finance Nexus

    Directory of Open Access Journals (Sweden)

    Valentin Toci

    2013-07-01

    Full Text Available The paper employs various measures of law enforcement to provide new evidence on the importance of legal institutions for different dimensions of financial development in transition economies. It offers a critical assessment of law enforcement measures employed in recent studies by showing that some proxies for law enforcement in the credit market may not be appropriate. Hence, care should be taken in how the quality of institutions is measured and the context which it represents. An original approach to measuring law enforcement in the credit market is developed by embodying the legal theory of dispute resolution and assessing this approach by collecting primary data for Kosovo. The findings suggest that Kosovo compares well with countries in the region and other transition economies in terms of the enforcement of creditor rights.

  13. Iron content of soils as a precipitation proxy

    Science.gov (United States)

    Dzombak, R.; Sheldon, N. D.

    2016-12-01

    Given that different iron phases form under different precipitation and drainage regimes, soil iron content could be used as a proxy for both volume and seasonality of precipitation. Constraining these factors is important for predicting future precipitation trends, especially for a warmer climate that will likely see more frequent extreme weather events. Specifically, using paleoprecipitation data from periods of higher temperatures and atmospheric CO2 concentrations helps inform models of future `greenhouse' climate. Forty-five modern samples from across the continental United States were analyzed, with MAP ranging from 200 to 1200 mm yr-1 and MAT ranging from 5 to 22°C. Soil types included Alfisols (N=15), Inceptisols (N=8), Mollisols (N=15), and Aridisols (N=7), and ranged from seasonally wet to well-drained. Analytical techniques included combustion-elemental analysis and organic carbon isotope analysis, a sequential iron extraction modified with a sodium hypochlorite step for the extraction of organic matter-bound iron, and the extraction of iron sulfides. The sequential extractions yield five different `pools' of iron found in sediment: crystalline iron oxides (e.g., goethite, hematite), magnetite, carbonate-bound, organic matter-bound, and labile/easily reducible iron minerals (e.g., ferrihydrite). Analysis by ICP-OES yielded a strong relationship between magnetite-bound iron and MAP, and fair relationships between the other iron pools and MAP. Individual soil orders tended to show stronger relationships to the iron pools than all soils analyzed together, potentially indicating the need for separate proxy relationships for each soil order. Pyrite concentrations were well below 1% by weight for these soils, suggesting that none of these soils has a long enough wet season to encourage its formation and that the presence vs. absence of pyrite in paleosols may be a useful proxy for soil moisture state. In contrast to some earlier work, no significant

  14. Carbohydrates and phenols as quantitative molecular vegetation proxies in peats

    Science.gov (United States)

    Kaiser, K.; Benner, R. H.

    2012-12-01

    Vegetation in peatlands is intricately linked to local environmental conditions and climate. Here we use chemical analyses of carbohydrates and phenols to reconstruct paleovegetation in peat cores collected from 56.8°N (SIB04), 58.4°N (SIB06), 63.8°N (G137) and 66.5°N (E113) in the Western Siberian Lowland. Lignin phenols (vanillyl and syringyl phenols) were sensitive biomarkers for vascular plant contributions and provided additional information on the relative contributions of angiosperm and gymnosperm plants. Specific neutral sugar compositions allowed identification of sphagnum mosses, sedges (Cyperaceae) and lichens. Hydroxyphenols released by CuO oxidation were useful tracers of sphagnum moss contributions. The three independent molecular proxies were calibrated with a diverse group of peat-forming plants to yield quantitative estimates (%C) of vascular plant, sphagnum moss and lichen contributions in peat core samples. Correlation analysis indicated the three molecular proxies produced fairly similar results for paleovegetation compositions, generally within the error interval of each approach (≤26%). The lignin-based method generally lead to higher estimates of vascular plant vegetation. Several significant deviations were also observed due to different reactivities of carbohydrate and phenolic polymers during peat decomposition. Rapid vegetation changes on timescales of 50-200 years were observed in the southern cores SIB04 and SIB06 over the last 2000 years. Vanillyl and syringyl phenol ratios indicated these vegetation changes were largely due to varying inputs of angiosperm and gymnosperm plants. The northern permafrost cores G137 and E113 showed a more stable development. Lichens briefly replaced sphagnum mosses and vascular plants in both of these cores. Shifts in vegetation did not correlate well with Northern hemisphere climate variability over the last 2000 years. This suggested that direct climate forcing of peatland dynamics was overridden

  15. Factitious Disorder by Proxy in Educational Settings: A Review

    Science.gov (United States)

    Frye, Ellen M.; Feldman, Marc D.

    2012-01-01

    Factitious disorder by proxy (FDP), historically known as Munchausen syndrome by proxy, is a diagnosis applied to parents and other caregivers who intentionally feign, exaggerate, and/or induce illness or injury in a child to get attention from health professionals and others. A review of the recent literature and our experience as consultants…

  16. Perbandingan proxy pada linux dan windows untuk mempercepat browsing website

    Directory of Open Access Journals (Sweden)

    Dafwen Toresa

    2017-05-01

    Full Text Available AbstrakPada saat ini sangat banyak organisasi, baik pendidikan, pemerintahan,  maupun perusahaan swasta berusaha membatasi akses para pengguna ke internet dengan alasan bandwidth yang dimiliki mulai terasa lambat ketika para penggunanya mulai banyak yang melakukan browsing ke internet. Mempercepat akses browsing menjadi perhatian utama dengan memanfaatkan teknologi Proxy server. Penggunaan proxy server perlu mempertimbangkan sistem operasi pada server dan tool yang digunakan belum diketahui performansi terbaiknya pada sistem operasi apa.  Untuk itu dirasa perlu untuk menganalisis performan Proxy server pada sistem operasi berbeda yaitu Sistem Operasi Linux dengan tools Squid  dan Sistem Operasi Windows dengan tool Winroute. Kajian ini dilakukan untuk mengetahui perbandingan kecepatan browsing dari komputer pengguna (client. Browser yang digunakan di komputer pengguna adalah Mozilla Firefox. Penelitian ini menggunakan 2 komputer klien dengan pengujian masing-masingnya 5 kali pengujian pengaksesan/browsing web yang dituju melalui proxy server. Dari hasil pengujian yang dilakukan, diperoleh kesimpulan bahwa penerapan proxy server di sistem operasi linux dengan tools squid lebih cepat browsing dari klien menggunakan web browser yang sama dan komputer klien yang berbeda dari pada proxy server sistem operasi windows dengan tools winroute.  Kata kunci: Proxy, Bandwidth, Browsing, Squid, Winroute AbstractAt this time very many organizations, both education, government, and private companies try to limit the access of users to the internet on the grounds that the bandwidth owned began to feel slow when the users began to do a lot of browsing to the internet. Speed up browsing access is a major concern by utilizing Proxy server technology. The use of proxy servers need to consider the operating system on the server and the tool used is not yet known the best performance on what operating system. For that it is necessary to analyze Performance Proxy

  17. Late Glacial to Holocene abrupt temperature changes recorded by Crenarchaeota in Lake Lucerne (Vierwaldstättersee, Switzerland)

    Science.gov (United States)

    Blaga, Cornelia I.; Reichart, Gert-Jan; Lotter, André F.; Anselmetti, Flavio; Sinninghe Damsté, Jaap S.

    2010-05-01

    In this study we applied the TEX86 (TetraEther Index of 86 carbon atoms) temperature proxy to a sediment core from Lake Lucerne (Vierwaldstättersee) to reconstruct, in almost decadal resolution, temperature changes during the Younger Dryas and the Early Holocene (ca. 14600 to 10600 cal. BP). The TEX86 proxy suggests a sequence of shifts during the late glacial period that strongly resemble the shifts in δ18O values from the Greenland ice core record. The TEX86-reconstructed lake temperature record indicates a step-wise pattern of climate changes across the studied interval with a shift from colder to warmer temperatures at the onset of the late-glacial interstadial, followed by an abrupt cooling at the onset of Younger Dryas and a rapid warming from 5.5 to 9°C at the Younger Dryas/Holocene transition in less than 200 years. The temperature change associated with the Interstadial-Younger Dryas alternation is ca. 4 °C and is in line with previous temperature reconstructions based on different proxies. The rapid changes in temperature associated with the last deglaciation are reflected in the highest possible detail in the TEX86 record. It is thus clear that our proxy, based on the isoprenoidal GDGTs (Glycerol Dialkyl Glycerol Tetraethers), is capable to reflect high resolution records of rapid (decadal to century scale oscillations) environmental fluctuations comparable with those obtained from ice cores.

  18. Fossilization and degradation of archaeal intact polar tetraether lipids in deeply buried marine sediments (Peru Margin)

    NARCIS (Netherlands)

    Lengger, S.K.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S.

    2014-01-01

    Glycerol dibiphytanyl glycerol tetraether (GDGT) lipids are part of the cellular membranes of Thaumarchaeota, an archaeal phylum composed of aerobic ammonia oxidizers, and are used in the paleotemperature proxy TEX86. GDGTs in live cells possess polar head groups and are called intact polar lipids

  19. Differential degradation of intact polar and core glycerol dialkyl glycerol tetraether lipids upon post-depositional oxidation

    NARCIS (Netherlands)

    Lengger, S.K.; Kraaij, M.; Tjallingii, R.; Baas, M.; Stuut, J.-B.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S.

    2013-01-01

    Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids (GDGTs) are used in various proxies, such as TEX86 and the BIT index. In living organism, they contain polar head groups (intact polar lipids – IPLs). IPL GDGTs have also been detected in ancient marine sediments and it is unclear

  20. Proxy SDN Controller for Wireless Networks

    Directory of Open Access Journals (Sweden)

    Won-Suk Kim

    2016-01-01

    Full Text Available Management of wireless networks as well as wired networks by using software-defined networking (SDN has been highlighted continually. However, control features of a wireless network differ from those of a wired network in several aspects. In this study, we identify the various inefficient points when controlling and managing wireless networks by using SDN and propose SDN-based control architecture called Proxcon to resolve these problems. Proxcon introduces the concept of a proxy SDN controller (PSC for the wireless network control, and the PSC entrusted with the role of a main controller performs control operations and provides the latest network state for a network administrator. To address the control inefficiency, Proxcon supports offloaded SDN operations for controlling wireless networks by utilizing the PSC, such as local control by each PSC, hybrid control utilizing the PSC and the main controller, and locally cooperative control utilizing the PSCs. The proposed architecture and the newly supported control operations can enhance scalability and response time when the logically centralized control plane responds to the various wireless network events. Through actual experiments, we verified that the proposed architecture could address the various control issues such as scalability, response time, and control overhead.

  1. Lithium in Brachiopods - proxy for seawater evolution?

    Science.gov (United States)

    Gaspers, Natalie; Magna, Tomas; Tomasovych, Adam; Henkel, Daniela

    2017-04-01

    Marine biogenic carbonates have the potential to serve as a proxy for evolution of seawater chemistry. In order to compile a record of the past and recent δ7Li in the oceans, foraminifera shells, scleractinian corals and belemnites have been used. However, only a foraminifera-based record appears to more accurately reflect the Li isotope composition of ocean water. At present, this record is available for the Cenozoic with implications for major events during this period of time, including K/T event [1]. A record for the entire Phanerozoic has not yet been obtained. In order to extend this record to the more distant past, Li elemental/isotope systematics of brachiopods were investigated because these marine animals were already present in Early Cambrian oceans and because they are less sensitive to diagenesis-induced modifications due to their shell mineralogy (low-Mg calcite). The preliminary data indicates a species-, temperature- and salinity-independent behavior of Li isotopes in brachiopod shells. Also, no vital effects have been observed for different shell parts. The consistent offset of -4‰ relative to modern seawater is in accordance with experimental data [2]. Further data are now being collected for Cenozoic specimens to more rigorously test brachiopods as possible archives of past seawater in comparison to the existing foraminiferal records. [1] Misra & Froelich (2012) Science 335, 818-823 [2] Marriott et al. (2004) Chem Geol 212, 5-15

  2. Deciphering dynamical proxy responses from lake sediments

    Science.gov (United States)

    Ramisch, Arne; Tjallingii, Rik; Hartmann, Kai; Brauer, Achim; Diekmann, Bernhard; Haberzettl, Torsten; Kasper, Thomas; Ahlborn, Marieke

    2017-04-01

    Lakes form a reliable archive of paleoenvironmental change in the terrestrial realm. Non-destructive XRF scans provide high-resolution records of element concentrations that are commonly related to past environmental change. However, XRF records of lake sediments enclose paleoenvironmental information that originates from multiple lake external and internal forcing. The variety of environmental forcing factors can complicate a direct identification of single mechanisms like climatic change from XRF or other proxy records. Here we present XRF records from several Asian lake archives, which indicate asynchronous variations of similar geochemical records since the late glacial/early Holocene. All XRF time series are characterized by damped harmonic oscillations of relative element concentrations through time. The asynchronous variations can be expressed by the frequency and the rate of damping of theses oscillations that differ between the lakes. We argue that the oscillatory behavior is a result of a feedback between the physical removal and dissolution of mineral phases in catchment soils and their subsequent enrichment and deposition within the lake. We present a numerical model, which accurately simulates major Holocene variations in the element concentration of lake records and discuss implications for the reconstruction of environmental signals from lake sediments.

  3. Assessing paleo-biodiversity using low proxy influx.

    Directory of Open Access Journals (Sweden)

    Olivier Blarquez

    Full Text Available We developed an algorithm to improve richness assessment based on paleoecological series, considering sample features such as their temporal resolutions or their volumes. Our new method can be applied to both high- and low-count size proxies, i.e. pollen and plant macroremain records, respectively. While pollen generally abounds in sediments, plant macroremains are generally rare, thus leading to difficulties to compute paleo-biodiversity indices. Our approach uses resampled macroremain influxes that enable the computation of the rarefaction index for the low influx records. The raw counts are resampled to a constant resolution and sample volume by interpolating initial sample ages at a constant time interval using the age∼depth model. Then, the contribution of initial counts and volume to each interpolated sample is determined by calculating a proportion matrix that is in turn used to obtain regularly spaced time series of pollen and macroremain influx. We applied this algorithm to sedimentary data from a subalpine lake situated in the European Alps. The reconstructed total floristic richness at the study site increased gradually when both pollen and macroremain records indicated a decrease in relative abundances of shrubs and an increase in trees from 11,000 to 7,000 cal BP. This points to an ecosystem change that favored trees against shrubs, whereas herb abundance remained stable. Since 6,000 cal BP, local richness decreased based on plant macroremains, while pollen-based richness was stable. The reconstructed richness and evenness are interrelated confirming the difficulty to distinguish these two aspects for the studies in paleo-biodiversity. The present study shows that low-influx bio-proxy records (here macroremains can be used to reconstruct stand diversity and address ecological issues. These developments on macroremain and pollen records may contribute to bridge the gap between paleoecology and biodiversity studies.

  4. Assessing paleo-biodiversity using low proxy influx.

    Science.gov (United States)

    Blarquez, Olivier; Finsinger, Walter; Carcaillet, Christopher

    2013-01-01

    We developed an algorithm to improve richness assessment based on paleoecological series, considering sample features such as their temporal resolutions or their volumes. Our new method can be applied to both high- and low-count size proxies, i.e. pollen and plant macroremain records, respectively. While pollen generally abounds in sediments, plant macroremains are generally rare, thus leading to difficulties to compute paleo-biodiversity indices. Our approach uses resampled macroremain influxes that enable the computation of the rarefaction index for the low influx records. The raw counts are resampled to a constant resolution and sample volume by interpolating initial sample ages at a constant time interval using the age∼depth model. Then, the contribution of initial counts and volume to each interpolated sample is determined by calculating a proportion matrix that is in turn used to obtain regularly spaced time series of pollen and macroremain influx. We applied this algorithm to sedimentary data from a subalpine lake situated in the European Alps. The reconstructed total floristic richness at the study site increased gradually when both pollen and macroremain records indicated a decrease in relative abundances of shrubs and an increase in trees from 11,000 to 7,000 cal BP. This points to an ecosystem change that favored trees against shrubs, whereas herb abundance remained stable. Since 6,000 cal BP, local richness decreased based on plant macroremains, while pollen-based richness was stable. The reconstructed richness and evenness are interrelated confirming the difficulty to distinguish these two aspects for the studies in paleo-biodiversity. The present study shows that low-influx bio-proxy records (here macroremains) can be used to reconstruct stand diversity and address ecological issues. These developments on macroremain and pollen records may contribute to bridge the gap between paleoecology and biodiversity studies.

  5. Reconstruction of late Quaternary marine and terrestrial environmental conditions of Northwest Africa and Southeast Australia : a multiple organic proxy study using marine sediments

    NARCIS (Netherlands)

    Alfama Lopes dos Santos, R.

    2012-01-01

    NW Africa and SE Australia are regions which are particularly vulnerable to climate change. In this thesis, organic proxies are used from marine sediment cores to reconstruct past environmental conditions from these areas. In sediments from NW Africa, the UK'37 showed an efficient proxy for sea

  6. A New Proxy Measurement Algorithm with Application to the Estimation of Vertical Ground Reaction Forces Using Wearable Sensors

    Directory of Open Access Journals (Sweden)

    Yuzhu Guo

    2017-09-01

    Full Text Available Measurement of the ground reaction forces (GRF during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0% using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra. Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.

  7. Proxies and consent discussions for dementia research.

    Science.gov (United States)

    Sugarman, Jeremy; Roter, Debra; Cain, Carole; Wallace, Roberta; Schmechel, Don; Welsh-Bohmer, Kathleen A

    2007-04-01

    To better understand the nature of informed consent encounters for research involving patients with dementia that requires proxy consent. Audiotaping of informed-consent encounters for a study of genetic markers for sporadic Alzheimer's disease. Outpatients at an Alzheimer's disease research center. Patients with dementia and their companions. Audiotapes were analyzed to characterize communication style and coverage of the standard elements of informed consent and, using the Roter Interaction Analysis System, to capture the dynamics of three-way interaction between the patient, their companion, and the physician investigator. Of 26 informed consent encounters, all involved a patient, a companion, and a physician. Patients had a mean Mini-Mental State Examination (MMSE) score of 21.8. For patients, 49% of their interactions involved agreement and approval (positive statements), 16% psychosocial information, 7% biomedical information, 7% asking questions, and 7% expressing emotion. Companion interactions involved 37% positive statements and 19% biomedical information. Physician interactions involved emotional expressiveness (30%) and positive statements (19%). Discussion length was positively related to MMSE score (Spearman rho=0.45; Pinformed consent was fairly comprehensive and had no relationship to patients' MMSE scores. These data should inform policies regarding the ethically appropriate ways of conducting research with cognitively impaired adults. For example, patients in this study were more silent than their companions and the physician, but when patients spoke, they primarily agreed with what was said. Although this might first seem to signal assent, such an interpretation should be made with caution for persons with dementia. In addition, previous work on informed consent has focused on its cognitive aspects, but these data reveal that the emotional and social dimensions warrant attention.

  8. The K-T Transition in Meghalaya, NE India

    Science.gov (United States)

    Gertsch, B.; Keller, G.; Adatte, T.; Garg, R.; Prasad, V.; Berner, Z.; Ateequzzaman, K.; Stueben, D.

    2008-12-01

    The TEX86 paleotemperature proxy, based on tetraether membrane lipids derived from aquatic Crenarchaeota has been applied in a variety of marine and lacustrine systems. A recent study analyzing a suite of 50 globally distributed lakes for TEX86 discovered that this proxy does not appear to work in all lake systems and that the TEX86 correlates well with both annual and winter lake surface water temperature in those systems where it does appear to work. Besides this observed empirical relationship between TEX86 values and lake surface temperatures, very little is known about the ecology of the crenarchaeota in lakes. We combined both biogeochemical and molecular techniques in a multiyear study of Lake Superior using both sediment trap collection of settling particulate matter over the annual cycle and filtration of suspended particulate matter from lake water to create vertical profiles of crenarchaeotal cell numbers and lipid concentrations to investigate the spatial and temporal ecology of the lacustrine Crenarchaeota. Initial results show that the flux of the tetraether lipids is highly seasonal and mainly occurs during two time periods in winter and spring. The flux-weighted TEX86-derived temperatures from the sediment trap material agrees with the TEX86 temperature from a sediment core top from the sampling site and mixed water temperatures during the two periods of highest flux within the error of the method. Spatially, lipids used in TEX86 are found throughout the water column when the Lake Superior is isothermal, but mainly in the hypolimnion when the lake is stratified. During stratification tetraether lipids in the eplimnion appear to reflect a surface water temperature, while the more abundant tetraether lipids in the hypolimnion reflect a deep water temperature. These data suggest that the TEX86 in sediments of Lake Superior mainly reflect the water temperatures of times of highest lipid flux, mixed with a smaller portion of lipids that are mainly

  9. Optimizing TCP Performance over UMTS with Split TCP Proxy

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    Abstract: The TCP performance over UMTS network is challenged by the large delay bandwidth product. Large delay bandwidth product is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer which are used to cope with radio transmission errors...... scenario (e.g.64 kbps). Besides, the split TCP proxy brings more performance gain for downloading large files than downloading small ones. To the end, for the configuration of the split proxy, an aggressive initial TCP congestion window size (e.g. 10 MSS) at proxy is particularly useful for radio links...

  10. Web proxy cache replacement strategies simulation, implementation, and performance evaluation

    CERN Document Server

    ElAarag, Hala; Cobb, Jake

    2013-01-01

    This work presents a study of cache replacement strategies designed for static web content. Proxy servers can improve performance by caching static web content such as cascading style sheets, java script source files, and large files such as images. This topic is particularly important in wireless ad hoc networks, in which mobile devices act as proxy servers for a group of other mobile devices. Opening chapters present an introduction to web requests and the characteristics of web objects, web proxy servers and Squid, and artificial neural networks. This is followed by a comprehensive review o

  11. The Brazos River (Texas) Sequence Shows Significant Cooling in the Waning Stages of the Tsunami Surges Caused by the Chicxulub Impact

    Science.gov (United States)

    Smit, J.; Vellekoop, J.

    2013-05-01

    silt and mudstone. TEX86 paleothermometry analyses of the top of the 10cm graded limestone and the subsequent mudstone shows a number of short seawater temperature drops from 30-31oC to 24-25oC, compatible with "nuclear winter" scenario temperature drops due to atmospheric sulphate aerosol and dust loads, directly following the weeks and month of the Chicxulub impact. The subsequent 1m thick continental shelf muds only contain rare, small reworked biota, and are correlatable to much thinner K-Pg boundary clay deposits elsewhere (El Kef, Zumaya, Caravaca). The first Paleocene indigenous form occurs 1m above the tsunami deposit, when temperatures are just above those of the latest Maastrichtian.

  12. The 30 cm radio flux as a solar proxy for thermosphere density modelling

    Directory of Open Access Journals (Sweden)

    Dudok de Wit Thierry

    2017-01-01

    Full Text Available The 10.7 cm radio flux (F10.7 is widely used as a proxy for solar UV forcing of the upper atmosphere. However, radio emissions at other centimetric wavelengths have been routinely monitored since the 1950 s, thereby offering prospects for building proxies that may be better tailored to space weather needs. Here we advocate the 30 cm flux (F30 as a proxy that is more sensitive than F10.7 to longer wavelengths in the UV and show that it improves the response of the thermospheric density to solar forcing, as modelled with DTM (Drag Temperature Model. In particular, the model bias drops on average by 0–20% when replacing F10.7 by F30; it is also more stable (the standard deviation of the bias is 15–40% smaller and the density variation at the the solar rotation period is reproduced with a 35–50% smaller error. We compare F30 to other solar proxies and discuss its assets and limitations.

  13. Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

    Science.gov (United States)

    Goslin, Jérôme; Clemmensen, Lars B.

    2017-10-01

    Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

  14. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    H.-J. Lüdecke; A. Hempelmann; Weiss, C. O.

    2012-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the 6 instrumental records for analysis by discrete Fourier transformation (DFT), wavelets, and the detrended fluctuati...

  15. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    OpenAIRE

    Lüdecke, H.-J.; A. Hempelmann; Weiss, C. O.

    2013-01-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detren...

  16. Munchausen syndrome by proxy presenting as hearing loss.

    Science.gov (United States)

    Ashraf, N; Thevasagayam, M S

    2014-06-01

    To review the diagnosis of Munchausen syndrome by proxy, a factitious disorder, in which symptoms are induced or feigned, usually in a child, by the caregiver. The involved caregiver seeks to gain attention or sympathy and often has a psychological need to maintain the sick role. We highlight the diagnostic difficulties and factors that may help with diagnosis in an otolaryngology setting. We present the case of Munchausen syndrome by proxy presenting with hearing loss in a five-year old boy, who was diagnosed eight years after his initial presentation. A literature review of Munchausen syndrome by proxy cases presenting with ENT symptoms is provided. Munchausen syndrome by proxy is a diagnosis that otolaryngologists should be aware of, particularly where recurrent or persistent illnesses in children, especially those involving otological symptoms, are refractory to the usual treatments.

  17. Munchausen Syndrome by Proxy: Unusual Manifestations and Disturbing Sequelae.

    Science.gov (United States)

    Porter, Gerald E.; And Others

    1994-01-01

    This study documents previously unreported findings in cases of Munchausen Syndrome by Proxy (in which a mother fabricates an illness in her child). In the reported case, esophageal perforation, retrograde intussusception, tooth loss, and bradycardia were found. (Author/DB)

  18. Applicability of a cognitive questionnaire in the elderly and proxy

    Directory of Open Access Journals (Sweden)

    Renata Areza Fegyveres

    Full Text Available Abstract The Informant Questionnaire on Cognitive Decline in the Elderly with the Proxy (IQCODE was developed as a screening tool for cognition alterations. Objectives: 1 To verify the applicability of IQCODE in the elderly with limited schooling, 2 To verify the reliability of the responses supplied by the aged and their proxies. Methods: Individuals of a Community Group were evaluated using the Mini-Mental State Examination (MMSE, IQCODE and Geriatric Depression Scale (GDS. The IQCODE was applied to informants and proxies. Results: We analyzed 44 individuals, aged between 58-82 years (M=66.8, SD=5.97 with mean elderly-schooling level of 3.75, SD=2.82 and 44 proxies aged 44.5 (SD=13.3, with mean schooling level of 8.25 (SD=4.3. The mean GDS was 8.22, SD=4.90 and 13 participants presented a score suggestive of depressive symptoms. The mean elderly IQCODE score was 3.26, SD=0.69 and 3.21, SD=0.65, for proxy responses. There was no statistical difference between these means. On the MMSE, the mean score was 24.20, SD=4.14 and 18 participants presented scores below the cut-off. The IQCODE answers by the elderly in this latter group were more congruent with MMSE than the answers of proxies. Conclusions: The applicability of the IQCODE in a population with little schooling was verified in that the proxy-report was similar to the elderly report. We can affirm that the elderly answers were more accurate than the proxies, as they were closer to MMSE score. The inclusion of a greater number of participants from community-dwelling settings is necessary to confirm the results obtained in this study.

  19. Proxy-rated quality of life in Alzheimer's disease

    DEFF Research Database (Denmark)

    Vogel, Asmus; Bhattacharya, Suvosree; Waldorff, Frans Boch

    2012-01-01

    The study investigated the change in proxy rated quality of life (QoL) of a large cohort of home living patients with Alzheimer's disease (AD) over a period of 36 months.......The study investigated the change in proxy rated quality of life (QoL) of a large cohort of home living patients with Alzheimer's disease (AD) over a period of 36 months....

  20. Millennial reconstructions: what can we learn from limited proxy data?

    Science.gov (United States)

    Annan, J. D.; Hargreaves, J. C.

    2011-12-01

    Reconstructions of the past millennium can help us to understand recent and future climate change, by placing the recent anthropogenically-forced changes in the context of natural variability. Proxy data prior to the instrumental era are, however, extremely limited, which raises the question of how well we can truly hope to understand the past. Until recently, temperature reconstructions over the past millennium have primarily used statistical regression-based methods, however approaches using data assimilation methodology (in which observational data are blended with dynamical climate models) have shown great potential and are being increasingly adopted. However, rigorous validation of these methods has been somewhat limited. Here we will present the results of some investigations into the performance, and the potential, of data assimilation approaches to estimate the climate state. We use a massive ensemble of the LOVECLIM model to generate precise results which (through being formally optimal) may be considered an upper bound on the performance of more realistic approaches. We show that the limited precision and volume of data places a severe constraint on our ability to reliably reconstruct past climate variability, especially prior to the middle of the last millennium.

  1. Munchausen syndrome by proxy mimicking as Gaucher disease.

    Science.gov (United States)

    Al-Owain, Mohammed; Al-Zaidan, Hamad; Al-Hashem, Amal; Kattan, Hoda; Al-Dowaish, Abdullah

    2010-08-01

    Although rare, Munchausen syndrome by proxy (MBP) is a potentially life-threatening form of child abuse. Here, we report a 19-month-old female infant who presented with hepatosplenomegaly, anemia, thrombocytopenia, and recurrent septicemia. She was initially thought to have myelodysplastic syndrome. Further hematological and immunological investigations revealed no cause. beta-Glucosylceramidase enzyme activity on dried blood spot was suggestive of Gaucher disease. However, the enzyme level on cultured skin fibroblast was not consistent with Gaucher disease. The first hint about MBP was the recurrent sepsis with numerous gram negative rods. Furthermore, the mother's behavior and health history raised our suspicion about MBP. The child showed significant improvement after she was separated from the mother for a week. Finally, the mother confessed that she was spitting in local herbs and injecting it into the central line. This is, to our knowledge, the first report of MBP resembling in its presentation Gaucher disease. This case should alert the general and specialized pediatricians about MBP, as it may mimic metabolic diseases like Gaucher disease.

  2. An Improved Quantum Proxy Blind Signature Scheme Based on Genuine Seven-Qubit Entangled State

    Science.gov (United States)

    Yang, Yuan-Yuan; Xie, Shu-Cui; Zhang, Jian-Zhong

    2017-07-01

    An improved quantum proxy blind signature scheme based on controlled teleportation is proposed in this paper. Genuine seven-qubit entangled state functions as quantum channel. We use the physical characteristics of quantum mechanics to implement delegation, signature and verification. Security analysis shows that our scheme is unforgeability, undeniability, blind and unconditionally secure. Meanwhile, we propose a trust party to provide higher security, the trust party is costless.

  3. Cryptanalysis of an inter-bank E-payment protocol based on quantum proxy blind signature

    Science.gov (United States)

    Cai, Xiao-Qiu; Wei, Chun-Yan

    2013-04-01

    We analyze the security of an inter-bank E-payment protocol based on quantum proxy blind signature, and find that there is a security leak in the quantum channels of this protocol, which gives a chance for an outside opponent to launch a special denial-of-service attack. Furthermore, we show that the dishonest merchant can succeed to change the purchase information of the customer in this protocol.

  4. Time-and-ID-Based Proxy Reencryption Scheme

    Directory of Open Access Journals (Sweden)

    Kambombo Mtonga

    2014-01-01

    Full Text Available Time- and ID-based proxy reencryption scheme is proposed in this paper in which a type-based proxy reencryption enables the delegator to implement fine-grained policies with one key pair without any additional trust on the proxy. However, in some applications, the time within which the data was sampled or collected is very critical. In such applications, for example, healthcare and criminal investigations, the delegatee may be interested in only some of the messages with some types sampled within some time bound instead of the entire subset. Hence, in order to carter for such situations, in this paper, we propose a time-and-identity-based proxy reencryption scheme that takes into account the time within which the data was collected as a factor to consider when categorizing data in addition to its type. Our scheme is based on Boneh and Boyen identity-based scheme (BB-IBE and Matsuo’s proxy reencryption scheme for identity-based encryption (IBE to IBE. We prove that our scheme is semantically secure in the standard model.

  5. Long Island Sound Water Temperatures During the Last Two Thousand Years

    Science.gov (United States)

    Warren, C. E.; Varekamp, J. C.; Thomas, E.

    2010-12-01

    influenced by the carbonate saturation state of the water. The tetraether index (TEX86) temperature proxy is based on the number of cyclopentane rings in the glycerol dialkyl glycerol tetraethers (GDGTs) from the membrane lipids of marine Crenarchaeota, which changes in response to temperature. Crenarcheota are one of the three major groups of non-thermophilic Archaea, a widely distributed, abundant and ecologically diverse group. This proxy can be used in organic-rich sediments deposited in many different settings. We analyzed samples for TEX86 in LIS cores in order to generate a 2,000 year temperature record. We compare the TEX86 paleotemperature record data (dominantly reflecting surface water temperatures) with a Mg/Ca record based on benthic foraminifera (reflecting bottom water temperatures), and an oxygen isotope record based on benthic foraminifera and corrected for salinity changes by using the Mg/Ca record. The Mg/Ca record appears to show evidence for the Little Ice Age and Medieval Warm Period. Preliminary TEX86 data indicate that temperatures of LIS waters, as averaged over the part of the year that the proxy organisms are biologically active, generally fluctuated between 12-14°C.

  6. A new way to proxy levels of infrastructure development

    Directory of Open Access Journals (Sweden)

    Steve Pickering

    2017-01-01

    Full Text Available Researchers in many fields have needed to develop a measure of infrastructure, and many proxies have been used toward this end, such as night light data and the Digital Chart of the World. Yet there are issues in using these methods. This paper presents a new way of proxying infrastructure: analysing the file sizes of map images on the Bing, Google, OpenStreetMap and Sina websites. The paper also demonstrates four ways in which this can be achieved. This approach is by no means perfect and does not solve all of the difficulties presented by other methods. Nevertheless, it does provide a simple and functional alternative proxy for level of infrastructure development.

  7. Munchausen Syndrome By Proxy Admitting with Bloody Urine and Stool

    Directory of Open Access Journals (Sweden)

    Tugba Koca

    2014-02-01

    Full Text Available Munchausen syndrome by Proxy is a severe form of child abuse. Disease symptoms and signs are fabricated or imitated by parents or caregivers The child is usually presented to doctors, persistently. A delay in diagnosis may cause severe negative impact on spiritual, physical, mental and social development of the cases and even death. Symptoms usually disappear in the absence of the perpetrators. The diagnosis is extremely difficult. A 21-month-old boy who had applied to many centers due to bleeding from various parts of the body for last six months, and whose symptoms could not be explained with any physical reason after tests were conducted. Finally he was admitted to our center with bloody urine and stools, and diagnosed Munchausen syndrome by proxy. In cases with recurrent hospital admission in whom no apparent disease is diagnosed, Munchausen syndrome by Proxy should be among the differential diagnosis.

  8. Research on implementation of proxy Arp in IP DSLAM

    Science.gov (United States)

    Cheng, Chuanqing; Wang, Li; Huang, Qiugen

    2005-02-01

    While the ethernet is applied more and more in public network environment and xdsl service become the most common access mode ,IP kenel DSLAM undertakes some functions such as service distribution and convergence ,security management and customer management.Facing the contradiction of the need of port isolation and the shortage of ip address,VLAN aggregation technology is applied in DSLAM.How to implement the communicatio between the two vlan but share the same ip subnet,proxy arp does this. This paper introduces how to implement proxy arp in the DSLAM. TCP/IP communication detail procedure betweent two host ,the relation of VLAN and network segment are discussed. The proxy arp model and its implementation in IP DSLAM is also expatiated in this paper and a conformance tesing is given.

  9. Proxy-Based IPv6 Neighbor Discovery Scheme for Wireless LAN Based Mesh Networks

    Science.gov (United States)

    Lee, Jihoon; Jeon, Seungwoo; Kim, Jaehoon

    Multi-hop Wireless LAN-based mesh network (WMN) provides high capacity and self-configuring capabilities. Due to data forwarding and path selection based on MAC address, WMN requires additional operations to achieve global connectivity using IPv6 address. The neighbor discovery operation over WLAN mesh networks requires repeated all-node broadcasting and this gives rise to a big burden in the entire mesh networks. In this letter, we propose the proxy neighbor discovery scheme for optimized IPv6 communication over WMN to reduce network overhead and communication latency. Using simulation experiments, we show that the control overhead and communication setup latency can be significantly reduced using the proxy-based neighbor discovery mechanism.

  10. The solar proxy κ1 Cet and the planetary habitability around the young Sun

    Science.gov (United States)

    do Nascimento, J.-D.; Vidotto, A. A.; Petit, P.; Folsom, C.; Porto de Mello, G. F.; Meibom, S.; Abrevaya, X. C.; Ribas, I.; Castro, M.; Marsden, S. C.; Morin, J.; Jeffers, S. V.; Guinan, E.; Bcool Collaboration

    2017-10-01

    Among the solar proxies, κ1 Cet, stands out as potentially having a mass very close to solar and a young age. We report magnetic field measurements and planetary habitability consequences around this star, a proxy of the young Sun when life arose on Earth. Magnetic strength was determined from spectropolarimetric observations and we reconstruct the large-scale surface magnetic field to derive the magnetic environment, stellar winds, and particle flux permeating the interplanetary medium around κ1 Cet. Our results show a closer magnetosphere and mass-loss rate 50 times larger than the current solar wind mass-loss rate when Life arose on Earth, resulting in a larger interaction via space weather disturbances between the stellar wind and a hypothetical young-Earth analogue, potentially affecting the habitability. Interaction of the wind from the young Sun with the planetary ancient magnetic field may have affected the young Earth and its life conditions.

  11. Solar forced Dansgaard-Oeschger events and their phase relation with solar proxies

    DEFF Research Database (Denmark)

    Ditlevsen, Peter; Braun, H.; Chialvo, D. R.

    2008-01-01

    of a highly nonlinear system to quasi-periodic solar forcing plus noise. This hypothesis was challenged as inconsistent with the observed variability in the phase relation between proxies of solar activity and Greenland climate. Here we reject the claim of inconsistency by showing that this phase variability...... is a robust, generic feature of the nonlinear dynamics of DO events, as described by a model. This variability is expected from the fact that the events are threshold crossing events, resulting from a cooperative process between the periodic forcing and the noise. This process produces a fluctuating phase...... relation with the periodic forcing, consistent with proxies of solar activity and Greenland climate. Udgivelsesdato: 25 March...

  12. Light is an active contributor to the vital effects of coral skeleton proxies

    Science.gov (United States)

    Juillet-Leclerc, Anne; Reynaud, Stéphanie; Dissard, Delphine; Tisserand, Guillaume; Ferrier-Pagès, Christine

    2014-09-01

    Symbiotic colonies of the coral Acropora sp. were cultured in a factorial design of three temperatures (21, 25 and 28 °C) and two light intensities (200 and 400 μmol photon m-2 s-1), under constant conditions. A temperature of 25 °C and a light intensity of 200 μmol photon m-2 s-1 was the starting culture condition. Metabolic (photosynthesis, respiration, calcification and surface expansion rate) and geochemical measurements (δ18O, δ13C, Sr/Ca and Mg/Ca) were conducted on 6 colonies for each experimental condition. Metabolic measurements confirmed that respiration, photosynthesis, calcification and surface expansion rate responded to the combined effect of temperature and light. Under each light intensity, mean calcification rate was linearly correlated with mean photosynthetic activity. Geochemical measurements were also influenced by temperature and, to a lesser degree, by light. All geochemical proxies measured on 6 nubbins showed a wide scattering of values, regardless of the environmental condition. Compared to the other proxies, δ18O exhibited a different behavior. It was the only proxy exhibiting temperature tracer behavior. However, while mean values of Sr/Ca, Mg/Ca and δ13C were well correlated, the correlation between the later and mean δ18O differed with light level. This suggests that both skeleton deposition and temperature oxygen fractionation differs according to light intensity. Overall, the effect of light on geochemical values seems to compromise the use of proxy calibrations solely based on temperature influence. Under high light conditions, the great amplitude shown by individual net photosynthesis is directly proportional to the highly variable zooxanthellae density. As light is affecting all of the proxies, we thus assume that the strong geochemical variability observed could be explained by various algae densities, each nubbin responding according to its zooxanthellae amount. Accordingly, we suggest that each symbiosome (the

  13. Health anxiety by proxy in women with severe health anxiety

    DEFF Research Database (Denmark)

    Thorgaard, Mette Viller; Frostholm, Lisbeth; Walker, Lynn

    2017-01-01

    Health anxiety (HA) refers to excessive worries and anxiety about harbouring serious illness based on misinterpretation of bodily sensations or changes as signs of serious illness. Severe HA is associated with disability and high health care costs. However, the impact of parental HA on excessive...... concern with their children's health (health anxiety by proxy) is scantly investigated. The aim of this study is to investigate HA by proxy in mothers with severe HA. Fifty mothers with severe HA and two control groups were included, i.e. mothers with rheumatoid arthritis (N = 49) and healthy mothers (N...

  14. From Antarctic ice cores to Australia's water resources: Investigating an alternative streamflow proxy

    Science.gov (United States)

    Tozer, Carly; Kiem, Anthony; Vance, Tessa; Roberts, Jason; Curran, Mark; Moy, Andrew

    2017-04-01

    Past research worldwide shows that streamflow reconstructions, developed from paleoclimate proxies, provide a broader view of the range of climate variability possible relative to the comparatively short instrumental flow records on which water resource management plans are currently based. Hence there is a clear need for the development of streamflow reconstructions to allow us to better manage our water resources into the future. In Australia, however, there is a dearth of local high resolution proxies, particularly in catchments of interest, from which to develop streamflow reconstructions. This has led researchers to look beyond catchment boundaries and also Australia's borders to explore the utility of remote proxies for reconstructing Australian streamflow. Here we investigate, for a case study catchment located on Australia's eastern seaboard, the development of a millennial-length, annual streamflow reconstruction based on 1013 years of summer sea salt deposition recorded in ice cores from East Antarctica. The streamflow reconstruction realistically captures interannual to decadal variability in the gauged streamflow over the 1929-2009 calibration period. For the pre-instrumental period (i.e. pre-1900), the streamflow reconstruction shows longer wet and dry epochs than those recorded in the instrumental period. Furthermore, the variation in the distribution of the duration of wet and dry epochs between centuries suggests that water resources management and planning based on the statistics of the last 100 years of data (or less) is problematic. This information can be utilised to generate more realistic flow scenarios that better capture the range of hydroclimatic variability that Australia has experienced. This work emphasises a novel combination of ice core science, paleoclimatology and catchment-scale hydrology that is now being used to develop more robust water resources planning and management. The continuing work to further develop ice core based

  15. A proxy analysis of urban air quality hazards in Bergen, Norway under a changing climate.

    Science.gov (United States)

    Wolf, Tobias; Esau, Igor; Reuder, Joachim

    2014-05-01

    allowing for high pollution events, showed only limited agreement with both the local proxy developed herein and the actual number of pollution events both on a monthly and on a seasonal basis. The NAO index showed an anti-correlation to the local proxy and the observations at least on a seasonal basis, the picture of the monthly basis was more unclear. Finally, the proxy was applied to NORESM CMIP 5 simulations to find the long term trend of the occurrence of adverse meteorological conditions for air quality in Bergen between 1950 and 2050. For this, the thresholds for the proxy had to be modified because the necessary NORESM data were only available as daily means. The prediction rates in ERA-Interim then changed to 77 % (detection rate), 61 % (false alarm rate) and 95 % (correct null prediction rate), respectively.

  16. Simulated airplane headache: a proxy towards identification of underlying mechanisms.

    Science.gov (United States)

    Bui, Sebastian Bao Dinh; Petersen, Torben; Poulsen, Jeppe Nørgaard; Gazerani, Parisa

    2017-12-01

    Airplane Headache (AH) occurs during flights and often appears as an intense, short lasting headache during take-off or landing. Reports are limited on pathological mechanisms underlying the occurrence of this headache. Proper diagnosis and treatments would benefit from identification of potential pathways involved in AH pathogenesis. This study aimed at providing a simulated airplane headache condition as a proxy towards identification of its underlying mechanisms. Fourteen participants including 7 volunteers suffering from AH and 7 healthy matched controls were recruited after meeting the diagnostic and safety criteria based on an approved study protocol. Simulation of AH was achieved by entering a pressure chamber with similar characteristics of an airplane flight. Selected potential biomarkers including salivary prostaglandin E2 (PGE2), cortisol, facial thermo-images, blood pressure, pulse, and saturation pulse oxygen (SPO) were defined and values were collected before, during and after flight simulation in the pressure chamber. Salivary samples were analyzed with ELISA techniques, while data analysis and statistical tests were handled with SPSS version 22.0. All participants in the AH-group experienced a headache attack similar to AH experience during flight. The non-AH-group did not experience any headaches. Our data showed that the values for PGE2, cortisol and SPO were significantly different in the AH-group in comparison with the non-AH-group during the flight simulation in the pressure chamber. The pressure chamber proved useful not only to provoke AH-like attack but also to study potential biomarkers for AH in this study. PGE2, and cortisol levels together with SPO presented dysregulation during the simulated AH-attack in affected individuals compared with healthy controls. Based on these findings we propose to use pressure chamber as a model to induce AH, and thus assess new potential biomarkers for AH in future studies.

  17. A Proxy Architecture to Enhance the Performance of WAP 2.0 by Data Compression

    Directory of Open Access Journals (Sweden)

    Yin Zhanping

    2005-01-01

    Full Text Available This paper presents a novel proxy architecture for wireless application protocol (WAP employing an advanced data compression scheme. Though optional in WAP , a proxy can isolate the wireless from the wired domain to prevent error propagations and to eliminate wireless session delays (WSD by enabling long-lived connections between the proxy and wireless terminals. The proposed data compression scheme combines content compression together with robust header compression (ROHC, which minimizes the air-interface traffic data, thus significantly reduces the wireless access time. By using the content compression at the transport layer, it also enables TLS tunneling, which overcomes the end-to-end security problem in WAP 1.x. Performance evaluations show that while WAP 1.x is optimized for narrowband wireless channels, WAP utilizing TCP/IP outperforms WAP 1.x over wideband wireless channels even without compression. The proposed data compression scheme reduces the wireless access time of WAP by over in CDMA2000 1XRTT channels, and in low-speed IS-95 channels, substantially reduces access time to give comparable performance to WAP 1.x. The performance enhancement is mainly contributed by the reply content compression, with ROHC offering further enhancements.

  18. A Proxy Architecture to Enhance the Performance of WAP 2.0 by Data Compression

    Directory of Open Access Journals (Sweden)

    Yin Zhanping

    2005-01-01

    Full Text Available This paper presents a novel proxy architecture for wireless application protocol (WAP 2.0 employing an advanced data compression scheme. Though optional in WAP 2.0 , a proxy can isolate the wireless from the wired domain to prevent error propagations and to eliminate wireless session delays (WSD by enabling long-lived connections between the proxy and wireless terminals. The proposed data compression scheme combines content compression together with robust header compression (ROHC, which minimizes the air-interface traffic data, thus significantly reduces the wireless access time. By using the content compression at the transport layer, it also enables TLS tunneling, which overcomes the end-to-end security problem in WAP 1.x. Performance evaluations show that while WAP 1.x is optimized for narrowband wireless channels, WAP 2.0 utilizing TCP/IP outperforms WAP 1.x over wideband wireless channels even without compression. The proposed data compression scheme reduces the wireless access time of WAP 2.0 by over 45% in CDMA2000 1XRTT channels, and in low-speed IS-95 channels, substantially reduces access time to give comparable performance to WAP 1.x. The performance enhancement is mainly contributed by the reply content compression, with ROHC offering further enhancements.

  19. Diffie-Hellman Key Based Authentication in Proxy Mobile IPv6

    Directory of Open Access Journals (Sweden)

    HyunGon Kim

    2010-01-01

    Full Text Available Wireless communication service providers have been showing strong interest in Proxy Mobile IPv6 for providing network-based IP mobility management. This could be a prominent way to support IP mobility to mobile nodes, because Proxy Mobile IPv6 requires minimal functionalities on the mobile node. While several extensions for Proxy Mobile IPv6 are being developed in the Internet Engineering Task Force, there has been little attentions paid to developing efficient authentication mechanisms. An authentication scheme for a mobility protocol must protect signaling messages against various security threats, e.g., session stealing attack, intercept attack by redirection, replay attack, and key exposure, while minimizing authentication latency. In this paper, we propose a Diffie-Hellman key based authentication scheme that utilizes the low layer signaling to exchange Diffie-Hellman variables and allows mobility service provisioning entities to exchange mobile node's profile and ongoing sessions securely. By utilizing the low layer signaling and context transfer between relevant nodes, the proposed authentication scheme minimizes authentication latency when the mobile node moves across different networks. In addition, thanks to the use of the Diffie-Hellman key agreement, pre-established security associations between mobility service provisioning entities are not required in the proposed authentication scheme so that network scalability in an operationally efficient manner is ensured. To ascertain its feasibility, security analysis and performance analysis are presented.

  20. Proxy indicators as measure of local economic dispositions in South ...

    African Journals Online (AJOL)

    Even though South Africa is in a more fortunate position with regard to the availability of such data, it also has data gaps, notably with regard to informal economic activities in the rural areas of the country. This exploratory article engages the use of proxy indicators to provide cues as to the state of a local economy.

  1. Proxy indicators as measure of local economic dispositions in South ...

    African Journals Online (AJOL)

    The growth of spare-part sales mirrors the behaviour of the national economy more accurately than used and new vehicles. BER: Retail Survey. (2005-2010). Used vehicles. 0.53. Spare Parts. 0.80. Banking-related proxy indicators. 13. House bonds. 0.43. Although some similarities exist between the national economy and ...

  2. Munchausen Syndrome by Proxy: A Study of Psychopathology.

    Science.gov (United States)

    Bools, Christopher; And Others

    1994-01-01

    This study evaluated 100 mothers with Munchausen Syndrome by Proxy (the fabrication of illness by a mother in her child). Approximately half of the mothers had either smothered or poisoned their child as part of their fabrications. Lifetime psychiatric histories were reported for 47 of the mothers. The most notable psychopathology was personality…

  3. Munchausen Syndrome by Proxy: Mother Fabricates Infant's Hearing Impairment.

    Science.gov (United States)

    Kahn, Gerri; Goldman, Ellen

    1991-01-01

    Case study reports a case of Munchausen Syndrome by Proxy, a form of child abuse in which the mother presents a child for treatment for a condition she herself has invented or created. This case study describes the ways in which a mother obtained a diagnosis of sensorineural hearing loss as well as amplification for her normally hearing infant.…

  4. Munchausen syndrome by adult proxy: a review of the literature.

    Science.gov (United States)

    Burton, M Caroline; Warren, Mark B; Lapid, Maria I; Bostwick, J Michael

    2015-01-01

    Munchausen syndrome by proxy (MSBP), more formally known as factitious disorder imposed on another, is a form of abuse in which a caregiver deliberately produces or feigns illness in a person under his or her care so that the proxy will receive medical care that gratifies the caregiver. Although well documented in the pediatric literature, few cases of MSBP with adult proxies (MSB-AP) have been reported. This study reviews existing literature on MSB-AP to provide a framework for clinicians to recognize this disorder. We searched Ovid MEDLINE, Ovid EMBASE, PubMed, Web of Knowledge, and PsychINFO, supplemented by bibliographic examination. We identified 13 cases of MSB-AP. Perpetrators were caregivers, most (62%) were women, and many worked in healthcare. The age range of the victims was 21 to 82 years. Most were unaware of the abuse, although in 2 cases the victim may have colluded with the perpetrator. Disease fabrication most often resulted from poisoning. MSB-AP should be included in the differential diagnosis of patients presenting with a complex constellation of symptoms without a unifying etiology and an overly involved caregiver with suspected psychological gain. Early identification is necessary so that healthcare providers do not unknowingly perpetuate harm through treatments that satisfy the perpetrator's psychological needs at the proxy's expense. © 2014 Society of Hospital Medicine.

  5. Identifying and Responding to Munchausen Syndrome by Proxy.

    Science.gov (United States)

    Pearl, Peggy T.

    1995-01-01

    Defines Munchausen Syndrome by Proxy in children up to eight years, in which the mother falsifies illness in her child by simulating or producing illness, bringing about frequent hospitalizations, painful tests, potentially harmful treatment, and in extreme cases, death. Describes symptoms and suggested professional actions. (DR)

  6. Munchausen by Proxy Victims in Adulthood: A First Look.

    Science.gov (United States)

    Libow, Judith A.

    1995-01-01

    Childhood experiences and long-term psychological outcomes were investigated with 10 adults, ages 33 through 71, who were self-identified victims of illness fabrication by a parent (Munchausen by Proxy). During childhood they felt unloved and unsafe and had emotional and physical problems. As adults, problems included insecurity, reality-testing…

  7. Munchausen Syndrome by Proxy (MSBP): An Intergenerational Perspective.

    Science.gov (United States)

    Rappaport, Sol R.; Hochstadt, Neil J.

    1993-01-01

    Presents new information about Munchausen Syndrome by Proxy (MSBP), factitious disorder in which caretaker may induce or exaggerate medical illness in his or her child that may lead to illness and even death. Provides psychosocial history of caregiver using intergenerational model. Presents case of MSBP involving three siblings and information…

  8. Shareholder Activism through Proxy Proposals : The European Perspective

    NARCIS (Netherlands)

    Cziraki, P.; Renneboog, L.D.R.; Szilagyi, P.G.

    2009-01-01

    This paper is the first to investigate the corporate governance role of shareholderinitiated proxy proposals in European firms. While proposals in the US are nonbinding even if they pass the shareholder vote, they are legally binding in the UK and most of Continental Europe. Nonetheless, submissions

  9. A comparison of Solar proxy-magnetometry diagnostics

    NARCIS (Netherlands)

    Leenaarts, J.|info:eu-repo/dai/nl/304837946; Rutten, R.J.|info:eu-repo/dai/nl/074143662; Carlsson, M.; Uitenbroek, H.

    2006-01-01

    Aims. We test various proxy-magnetometry diagnostics, i.e., brightness signatures of small-scale magnetic elements, for studying magnetic field structures in the solar photosphere. Methods. Images are numerically synthesized from a 3D solar magneto-convection simulation for, respectively, the G band

  10. Munchausen by Proxy (MBP) Maltreatment: An International Educational Challenge.

    Science.gov (United States)

    Lasher, Louisa J.

    2003-01-01

    This article is an introduction to a special section on Munchausen Syndrome by Proxy (MSBP) as a form of child maltreatment. In MSBP the perpetrator has deliberately induced, fabricated, or exaggerated a physical and/or psychological-behavioral-mental health problem in another. The article stresses the importance of obtaining an MSBP finding of…

  11. SINOMA - a better tool for proxy based reconstructions?

    Science.gov (United States)

    Buras, Allan; Thees, Barnim; Czymzik, Markus; Dräger, Nadine; Kienel, Ulrike; Neugebauer, Ina; Ott, Florian; Scharnweber, Tobias; Simard, Sonia; Slowinski, Michal; Slowinski, Sandra; Tecklenburg, Christina; Zawiska, Izabela; Wilmking, Martin

    2014-05-01

    Our knowledge on past environmental conditions largely relies on reconstructions that are based on linear regressions between proxy variables (e.g. tree-rings, lake sediments, ice cores) covering a comparably long period (centuries to millennia) and environmental parameters (e.g. climate data) of which only rather short measurement series exist (mostly decades). In general, the corresponding measurements are prone to errors. For instance, air temperature records that are to be prolonged by reconstruction from tree-rings are normally not measured in situ, i.e. where the trees used for reconstructions are growing. In contrast, the variation of tree-ring properties which are used as proxies does not only depend on temperature variations but also on other environmental variables and biological effects. However, if regressions are based on noisy data, knowledge on the noise intensity of both predictor and predictand is needed and model parameter estimates (slope and intercept) will be erroneous if information on the noise is not included in their estimation (Kutzbach et al., 2011). Here, we investigate the performance of the new Sequential Iterative Noise Matching Algorithm (SINOMA; Thees et al., 2009; and Thees et al., submitted) on a variety of typical proxy-data of differing temporal resolution (i.e. hourly (dendrometers, piezometers), seasonally (tree-rings), and annually (tree rings and varved lake sediments)). For each of the investigated proxies a number of pseudo-proxy datasets is generated. I.e. to each proxy variable two different noises are added, resulting in two noisy variables that originate from a common signal (the proxy) and of which the respective error noises and the true model parameters (slope and intercept) between both are known. SINOMA is applied to each of these pseudo-proxy datasets and its performance is evaluated against traditional regression techniques. The herewith submitted contribution thus focuses on the applicability of SINOMA rather

  12. Impact of spatial proxies on the representation of bottom-up emission inventories: A satellite-based analysis

    Science.gov (United States)

    Geng, Guannan; Zhang, Qiang; Martin, Randall V.; Lin, Jintai; Huo, Hong; Zheng, Bo; Wang, Siwen; He, Kebin

    2017-03-01

    Spatial proxies used in bottom-up emission inventories to derive the spatial distributions of emissions are usually empirical and involve additional levels of uncertainty. Although uncertainties in current emission inventories have been discussed extensively, uncertainties resulting from improper spatial proxies have rarely been evaluated. In this work, we investigate the impact of spatial proxies on the representation of gridded emissions by comparing six gridded NOx emission datasets over China developed from the same magnitude of emissions and different spatial proxies. GEOS-Chem-modeled tropospheric NO2 vertical columns simulated from different gridded emission inventories are compared with satellite-based columns. The results show that differences between modeled and satellite-based NO2 vertical columns are sensitive to the spatial proxies used in the gridded emission inventories. The total population density is less suitable for allocating NOx emissions than nighttime light data because population density tends to allocate more emissions to rural areas. Determining the exact locations of large emission sources could significantly strengthen the correlation between modeled and observed NO2 vertical columns. Using vehicle population and an updated road network for the on-road transport sector could substantially enhance urban emissions and improve the model performance. When further applying industrial gross domestic product (IGDP) values for the industrial sector, modeled NO2 vertical columns could better capture pollution hotspots in urban areas and exhibit the best performance of the six cases compared to satellite-based NO2 vertical columns (slope = 1.01 and R2 = 0. 85). This analysis provides a framework for information from satellite observations to inform bottom-up inventory development. In the future, more effort should be devoted to the representation of spatial proxies to improve spatial patterns in bottom-up emission inventories.

  13. Near coast sedimentary stratigraphy as a proxy for climatic instability

    Science.gov (United States)

    McLivenny, J.

    2009-04-01

    Several studies have indicated a link between climatic deterioration and dune stability (Wilson 2002, Issar 2003, Dawson et al 2004). The frequency and magnitude of storms have been cited as a key variable in the stability of large dune systems. For the stratigraphy of dune systems to act as a regional climatic proxy there must be a good regional relationship between known climatic events and regionally correlated stratigraphic changes. Dunnet Bay in Caithness, Northern Scotland was chosen as a study site to look at the relationship between dune stability and climatic change during the late Holocene in Northern Scotland. Dunnet Bay was chosen for its physical attributes which make it an excellent natural sediment trap. Tucked in between headlands which act as barriers to long-shore transport the predominant movement of sediment there is straight onshore, with only minor amounts being lost to the sea. The immediate back-dune stratigraphy, colloquially known as "links", provided evidence of peat formation and dune stability. Stratigraphy was mapped using traditional field techniques and ground penetrating radar. The cores consisted mostly of massive layers of sand interleaved with peat. Sand layers were dated with optically stimulated luminescence (OSL) and interpreted as reflecting high wind energy regimes transporting sand inland. Peat layers were C14 dated and taken as representing climatic stability. Stratigraphy was mapped using hand auguring, percussion coring, and open sections. Ground penetrating radar was also used to look at the continuity of key layers. OSL dating in two open sections showed dates obtained from the first section (1790 AD ±70, 53 BC ± 100, 300 BC ± 100, 400 BC ± 100) mapped to the top of the second section (1800 AD ± 100, 1500 BC ± 200, 2900 BC ± 300) which was consistent with stratigraphy increasing sediment thickness towards the centre of the bay. The results were consistent with acquired C14 dates from selected peat layers. Taken

  14. A new proxy of comet impacts?

    Science.gov (United States)

    Kasatkina, E.; Shumilov, O.; Lukina, N.

    exploded above the Chulym river, Siberia (57.7N; 85.1E) on 26 February, 1984. The TNT equivalent of Chulym explosion was 10 Kt, that is rather less than the TNT equivalent of the Tunguska explosion (10-40 Mt). The results of analysis showed that tree-rings can be used to detect impacts of Tunguska-sized and smaller bodies meters to tens of meters in size. The work was supported by a grant from the Russian Foundation for Basic Research (grant N 05-04-97528), by the Program 'Biodiversity and dynamics of gene pool' of the Russian Academy and by the Regional Scientific Program of the Murmansk region.

  15. Assessing 5 years of GOSAT Proxy XCH4 data and associated uncertainties

    Directory of Open Access Journals (Sweden)

    R. J. Parker

    2015-11-01

    Full Text Available We present 5 years of GOSAT XCH4 retrieved using the "proxy" approach. The Proxy XCH4 data are validated against ground-based TCCON observations and are found to be of high quality with a small bias of 4.8 ppb (∼ 0.27 % and a single-sounding precision of 13.4 ppb (∼ 0.74 %. The station-to-station bias (ameasure of the relative accuracy is found to be 4.2 ppb. For the first time the XCH4 / XCO2 ratio component of the Proxy retrieval is validated (bias of 0.014 ppb ppm−1 (∼ 0.30 %, single-sounding precision of 0.033 ppb ppm−1 (∼ 0.72 %. The uncertainty relating to the model XCO2 component of the Proxy XCH4 is assessed through the use of an ensemble of XCO2 models. While each individual XCO2 model is found to agree well with the TCCON validation data (r = 0.94–0.97, it is not possible to select one model as the best from our comparisons. The median XCO2 value of the ensemble has a smaller scatter against TCCON (a standard deviation of 0.92 ppm than any of the individual models whilst maintaining a small bias (0.15 ppm. This model median XCO2 is used to calculate the Proxy XCH4 with the maximum deviation of the ensemble from the median used as an estimate of the uncertainty. We compare this uncertainty to the a posteriori retrieval error (which is assumed to reduce with sqrt(N and find typically that the model XCO2 uncertainty becomes significant during summer months when the a posteriori error is at its lowest due to the increase in signal related to increased summertime reflected sunlight. We assess the significance of these model and retrieval uncertainties on flux inversion by comparing the GOSAT XCH4 against modelled XCH4 from TM5-4DVAR constrained by NOAA surface observations (MACC reanalysis scenario S1-NOAA. We find that for the majority of regions the differences are much larger than the estimated uncertainties. Our findings show that useful information will be provided to the inversions for the majority of regions in addition

  16. Assessing 5 years of GOSAT Proxy XCH4 data and associated uncertainties

    Science.gov (United States)

    Parker, R. J.; Boesch, H.; Byckling, K.; Webb, A. J.; Palmer, P. I.; Feng, L.; Bergamaschi, P.; Chevallier, F.; Notholt, J.; Deutscher, N.; Warneke, T.; Hase, F.; Sussmann, R.; Kawakami, S.; Kivi, R.; Griffith, D. W. T.; Velazco, V.

    2015-11-01

    We present 5 years of GOSAT XCH4 retrieved using the "proxy" approach. The Proxy XCH4 data are validated against ground-based TCCON observations and are found to be of high quality with a small bias of 4.8 ppb (∼ 0.27 %) and a single-sounding precision of 13.4 ppb (∼ 0.74 %). The station-to-station bias (ameasure of the relative accuracy) is found to be 4.2 ppb. For the first time the XCH4 / XCO2 ratio component of the Proxy retrieval is validated (bias of 0.014 ppb ppm-1 (∼ 0.30 %), single-sounding precision of 0.033 ppb ppm-1 (∼ 0.72 %)). The uncertainty relating to the model XCO2 component of the Proxy XCH4 is assessed through the use of an ensemble of XCO2 models. While each individual XCO2 model is found to agree well with the TCCON validation data (r = 0.94-0.97), it is not possible to select one model as the best from our comparisons. The median XCO2 value of the ensemble has a smaller scatter against TCCON (a standard deviation of 0.92 ppm) than any of the individual models whilst maintaining a small bias (0.15 ppm). This model median XCO2 is used to calculate the Proxy XCH4 with the maximum deviation of the ensemble from the median used as an estimate of the uncertainty. We compare this uncertainty to the a posteriori retrieval error (which is assumed to reduce with sqrt(N)) and find typically that the model XCO2 uncertainty becomes significant during summer months when the a posteriori error is at its lowest due to the increase in signal related to increased summertime reflected sunlight. We assess the significance of these model and retrieval uncertainties on flux inversion by comparing the GOSAT XCH4 against modelled XCH4 from TM5-4DVAR constrained by NOAA surface observations (MACC reanalysis scenario S1-NOAA). We find that for the majority of regions the differences are much larger than the estimated uncertainties. Our findings show that useful information will be provided to the inversions for the majority of regions in addition to that

  17. Quick, “Imputation-free” meta-analysis with proxy-SNPs

    Directory of Open Access Journals (Sweden)

    Meesters Christian

    2012-09-01

    Full Text Available Abstract Background Meta-analysis (MA is widely used to pool genome-wide association studies (GWASes in order to a increase the power to detect strong or weak genotype effects or b as a result verification method. As a consequence of differing SNP panels among genotyping chips, imputation is the method of choice within GWAS consortia to avoid losing too many SNPs in a MA. YAMAS (Yet Another Meta Analysis Software, however, enables cross-GWAS conclusions prior to finished and polished imputation runs, which eventually are time-consuming. Results Here we present a fast method to avoid forfeiting SNPs present in only a subset of studies, without relying on imputation. This is accomplished by using reference linkage disequilibrium data from 1,000 Genomes/HapMap projects to find proxy-SNPs together with in-phase alleles for SNPs missing in at least one study. MA is conducted by combining association effect estimates of a SNP and those of its proxy-SNPs. Our algorithm is implemented in the MA software YAMAS. Association results from GWAS analysis applications can be used as input files for MA, tremendously speeding up MA compared to the conventional imputation approach. We show that our proxy algorithm is well-powered and yields valuable ad hoc results, possibly providing an incentive for follow-up studies. We propose our method as a quick screening step prior to imputation-based MA, as well as an additional main approach for studies without available reference data matching the ethnicities of study participants. As a proof of principle, we analyzed six dbGaP Type II Diabetes GWAS and found that the proxy algorithm clearly outperforms naïve MA on the p-value level: for 17 out of 23 we observe an improvement on the p-value level by a factor of more than two, and a maximum improvement by a factor of 2127. Conclusions YAMAS is an efficient and fast meta-analysis program which offers various methods, including conventional MA as well as inserting proxy

  18. Quick, "imputation-free" meta-analysis with proxy-SNPs.

    Science.gov (United States)

    Meesters, Christian; Leber, Markus; Herold, Christine; Angisch, Marina; Mattheisen, Manuel; Drichel, Dmitriy; Lacour, André; Becker, Tim

    2012-09-12

    Meta-analysis (MA) is widely used to pool genome-wide association studies (GWASes) in order to a) increase the power to detect strong or weak genotype effects or b) as a result verification method. As a consequence of differing SNP panels among genotyping chips, imputation is the method of choice within GWAS consortia to avoid losing too many SNPs in a MA. YAMAS (Yet Another Meta Analysis Software), however, enables cross-GWAS conclusions prior to finished and polished imputation runs, which eventually are time-consuming. Here we present a fast method to avoid forfeiting SNPs present in only a subset of studies, without relying on imputation. This is accomplished by using reference linkage disequilibrium data from 1,000 Genomes/HapMap projects to find proxy-SNPs together with in-phase alleles for SNPs missing in at least one study. MA is conducted by combining association effect estimates of a SNP and those of its proxy-SNPs. Our algorithm is implemented in the MA software YAMAS. Association results from GWAS analysis applications can be used as input files for MA, tremendously speeding up MA compared to the conventional imputation approach. We show that our proxy algorithm is well-powered and yields valuable ad hoc results, possibly providing an incentive for follow-up studies. We propose our method as a quick screening step prior to imputation-based MA, as well as an additional main approach for studies without available reference data matching the ethnicities of study participants. As a proof of principle, we analyzed six dbGaP Type II Diabetes GWAS and found that the proxy algorithm clearly outperforms naïve MA on the p-value level: for 17 out of 23 we observe an improvement on the p-value level by a factor of more than two, and a maximum improvement by a factor of 2127. YAMAS is an efficient and fast meta-analysis program which offers various methods, including conventional MA as well as inserting proxy-SNPs for missing markers to avoid unnecessary power loss

  19. Mobile Multicast in Hierarchical Proxy Mobile IPV6

    Science.gov (United States)

    Hafizah Mohd Aman, Azana; Hashim, Aisha Hassan A.; Mustafa, Amin; Abdullah, Khaizuran

    2013-12-01

    Mobile Internet Protocol Version 6 (MIPv6) environments have been developing very rapidly. Many challenges arise with the fast progress of MIPv6 technologies and its environment. Therefore the importance of improving the existing architecture and operations increases. One of the many challenges which need to be addressed is the need for performance improvement to support mobile multicast. Numerous approaches have been proposed to improve mobile multicast performance. This includes Context Transfer Protocol (CXTP), Hierarchical Mobile IPv6 (HMIPv6), Fast Mobile IPv6 (FMIPv6) and Proxy Mobile IPv6 (PMIPv6). This document describes multicast context transfer in hierarchical proxy mobile IPv6 (H-PMIPv6) to provide better multicasting performance in PMIPv6 domain.

  20. A comparison of proxy performance in coral biodiversity monitoring

    Science.gov (United States)

    Richards, Zoe T.

    2013-03-01

    The productivity and health of coral reef habitat is diminishing worldwide; however, the effect that habitat declines have on coral reef biodiversity is not known. Logistical and financial constraints mean that surveys of hard coral communities rarely collect data at the species level; hence it is important to know if there are proxy metrics that can reliably predict biodiversity. Here, the performances of six proxy metrics are compared using regression analyses on survey data from a location in the northern Great Barrier Reef. Results suggest generic richness is a strong explanatory variable for spatial patterns in species richness (explaining 82 % of the variation when measured on a belt transect). The most commonly used metric of reef health, percentage live coral cover, is not positively or linearly related to hard coral species richness. This result raises doubt as to whether management actions based on such reefscape information will be effective for the conservation of coral biodiversity.

  1. False allegations of abuse and Munchausen syndrome by proxy.

    Science.gov (United States)

    Meadow, R

    1993-01-01

    Fourteen children from seven families are reported for whom false allegations of abuse were made by the mother. Twelve children were alleged to have incurred sexual abuse, one both sexual and physical abuse, and one physical abuse alone. Thirteen of the children had incurred, or were currently victims of, factitious illness abuse invented by the mother. The one child with no history of factitious illness abuse had a sibling who had incurred definite factitious illness abuse. The false allegations of abuse did not occur in the context of parental separation, divorce, or custody disputes concerning the children. They occurred in the context of Munchausen syndrome by proxy abuse. The age of the children, 3 to 9 years, was older than the usual age for Munchausen syndrome by proxy abuse. The mother was the source of the false allegations and was the person who encouraged or taught six of the children to substantiate allegations of sexual abuse. PMID:8503664

  2. Munchausen syndrome and Munchausen syndrome by proxy in dermatology.

    Science.gov (United States)

    Boyd, Alan S; Ritchie, Coleman; Likhari, Sunaina

    2014-08-01

    Patients with Munchausen syndrome purposefully injure themselves, often with the injection of foreign materials, to gain hospital admission and the attention associated with having a difficult-to-identify condition. Munchausen syndrome by proxy occurs when a child's caregiver, typically the mother, injures the child for the same reasons. Cases of Munchausen syndrome and Munchausen syndrome by proxy with primary cutaneous involvement appear to be rarely described in the literature suggesting either that diagnosis is not made readily or that it is, in fact, an uncommon disorder. At the center of both conditions is significant psychological pathology and treatment is difficult as many patients with Munchausen syndrome when confronted with these diagnostic possibilities simply leave the hospital. Little is known about the long-term outcome or prognosis of these patients. Copyright © 2014 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  3. A case report of Factitious Disorder (Munchausen Syndrome by proxy

    Directory of Open Access Journals (Sweden)

    Mehdi Shirzadifar

    2014-09-01

    Full Text Available Background: In Factitious Disorder by proxy, one person (perpetrator induces the disease in another person, thereby seeking emotional needs during the treatment process Diagnosis of this disorder is very difficult and there is not much consensus over it among experts. Lack of timely diagnosis of this disorder may lead to serious harms in patients. Case presentation: We will introduce a 19 year-old boy with mental retardation and history of multiple admissions to psychiatric, internal, urology and surgery wards. He has a 12 year-old sister and a 4 year-old brother, both with history of multiple admissions to pediatrics and internal wards. The father of family was 48 years old with chronic mental disorder, drug dependency and history of multiple admissions to medical, psychiatry and neurology wards. The mother of this family was diagnosed with munchausen syndrome by proxy.

  4. Munchausen syndrome by proxy: an alarming face of child abuse.

    Science.gov (United States)

    Gehlawat, Pratibha; Gehlawat, Virender Kumar; Singh, Priti; Gupta, Rajiv

    2015-01-01

    Munchausen syndrome by proxy (MSBP) is emerging as a serious form of child abuse. It is an intentional production of illness in another, usually children by mothers, to assume sick role by proxy. It is poorly understood and a controversial diagnosis. Treatment is very difficult. We present a case of 9-year-old boy brought to Pt. B. D. Sharma, PGIMS, Rohtak, a tertiary care hospital in northern India by his father and paternal uncle with complaints of hematemesis since July 2012. He underwent many invasive procedures until the diagnosis of MSBP was finally considered. The examination of the blood sample confirmed the diagnosis. The child was placed under custody of his mother. The case was reported to social services, which incorporated whole family in the management.

  5. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies...... are made from digital scans of the original dias slides located in the collection of the Museum of Contemporary Art in Roskilde. In front of the audience entering the space and placed on it’s own stand, is an original 60s style telephone with turning dial. Action begins when the audience lift the phone...... and dial a number. Any number will make the Dias change. All numbers are also assigned to specific sound documents: clips form rare interviews and the complete sound-re-enactment of the Show-Bix piece ‘Omringning’ (‘Surrounding’) in five channels (a quintophonie). This was originally produced...

  6. Show and Tell

    DEFF Research Database (Denmark)

    2013-01-01

    Fredag d. 1 november blev Kunsthal Charlottenborg indtaget af performanceprogrammet Show & Tell med et bredspektret program af danske og internationale kunstnere indenfor performance-, lyd- og installationskunst. Programmet præsenterer værker, der undersøger kroppens stadig mere symbiotiske forhold...... og studienævnet på Performance-design. Show & Tell - Performance program: kl. 16.30-19 Adresse: Kunsthal Charlottenborg, Nyhavn 2, 1051 København K...

  7. Proxy-SU(3) symmetry in heavy deformed nuclei

    Science.gov (United States)

    Bonatsos, Dennis; Assimakis, I. E.; Minkov, N.; Martinou, Andriana; Cakirli, R. B.; Casten, R. F.; Blaum, K.

    2017-06-01

    Background: Microscopic calculations of heavy nuclei face considerable difficulties due to the sizes of the matrices that need to be solved. Various approximation schemes have been invoked, for example by truncating the spaces, imposing seniority limits, or appealing to various symmetry schemes such as pseudo-SU(3). This paper proposes a new symmetry scheme also based on SU(3). This proxy-SU(3) can be applied to well-deformed nuclei, is simple to use, and can yield analytic predictions. Purpose: To present the new scheme and its microscopic motivation, and to test it using a Nilsson model calculation with the original shell model orbits and with the new proxy set. Method: We invoke an approximate, analytic, treatment of the Nilsson model, that allows the above vetting and yet is also transparent in understanding the approximations involved in the new proxy-SU(3). Results: It is found that the new scheme yields a Nilsson diagram for well-deformed nuclei that is very close to the original Nilsson diagram. The specific levels of approximation in the new scheme are also shown, for each major shell. Conclusions: The new proxy-SU(3) scheme is a good approximation to the full set of orbits in a major shell. Being able to replace a complex shell model calculation with a symmetry-based description now opens up the possibility to predict many properties of nuclei analytically and often in a parameter-free way. The new scheme works best for heavier nuclei, precisely where full microscopic calculations are most challenged. Some cases in which the new scheme can be used, often analytically, to make specific predictions, are shown in a subsequent paper.

  8. Fingerprinting Reverse Proxies Using Timing Analysis of TCP Flows

    Science.gov (United States)

    2013-09-01

    Address Translation NPS Naval Postgraduate School OTT One-way Transit Time PET Privacy Enhancing Technology PHP Hypertext Preprocessor P2P ] Peer-to...of timing information that can translate into usable intelligence for detecting the use of reverse proxies by a network domain. 1.1 Problem Statement...websites (i.e., Sky News Arabia, Kemalist Gazete, Detroit News), and entertainment industry sites (i.e., HBO GO, LeoVegas Online Casino , FreeRide Games

  9. MUNCHAUSEN SYNDROME BY PROXY IN PEDIATRIC DENTISTRY: MYTH OR REALITY?

    Directory of Open Access Journals (Sweden)

    Veronica PINTILICIUC-ŞERBAN

    2017-06-01

    Full Text Available Background and aims: Munchausen syndrome by proxy is a condition traditionally comprising physical and mental abuse and medical neglect as a form of psychogenic maltreatment of the child, secondary to fabrication of a pediatric illness by the parent or guardian. The aim of our paper is to assess whether such condition occurs in current pediatric dental practice and to evidence certain situations in which the pediatric dentist should suspect this form of child abuse. Problem statement: Munchausen syndrome by proxy in pediatric dentistry may lead to serious chronic disabilities of the abused or neglected child, being one of the causes of treatment failure. Discussion: Prompt detection of such condition should be regarded as one of the duties of the practitioner who should be trained to report the suspected cases to the governmental child protective agencies. This should be regarded as a form of child abuse and neglect, and the responsible caregiver could be held liable when such wrongful actions cause harm or endanger child’s welfare. Conclusion: Munchausen syndrome by proxy should be regarded as a reality in current pediatric dental practice and dental teams should be trained to properly recognize, assess and manage such complex situations.

  10. Short-term indicators. Intensities as a proxy for savings

    Energy Technology Data Exchange (ETDEWEB)

    Boonekamp, P.G.M.; Gerdes, J. [ECN Policy Studies, Petten (Netherlands); Faberi, S. [Institute of Studies for the Integration of Systems ISIS, Rome (Italy)

    2013-12-15

    The ODYSSEE database on energy efficiency indicators (www.odyssee-indicators.org) has been set up to enable the monitoring and evaluation of realised energy efficiency improvements and related energy savings. The database covers the 27 EU countries as well as Norway and Croatia and data are available from 1990 on. This work contributes to the growing need for quantitative monitoring and evaluation of the impacts of energy policies and measures, both at the EU and national level, e.g. due to the Energy Services Directive and the proposed Energy Efficiency Directive. Because the underlying data become available only after some time, the savings figures are not always timely available. This is especially true for the ODEX efficiency indices per sector that rely on a number of indicators. Therefore, there is a need for so-called short-term indicators that become available shortly after the year has passed for which data are needed. The short term indicators do not replace the savings indicators but function as a proxy for the savings in the most recent year. This proxy value is faster available, but will be less accurate than the saving indicators themselves. The short term indicators have to be checked regularly with the ODEX indicators in order to see whether they can function still as a proxy.

  11. A unified proxy for ENSO and PDO variability since 1650

    Directory of Open Access Journals (Sweden)

    S. McGregor

    2010-01-01

    Full Text Available In this manuscript we have attempted to consolidate the common signal in previously defined proxy reconstructions of the El Niño-Southern Oscillation into one individual proxy titled the Unified ENSO Proxy (UEP. While correlating well with the majority of input reconstructions, the UEP provides better representation of observed indices of ENSO, discrete ENSO events and documented historical chronologies of ENSO than any of these input ENSO reconstructions. Further to this, the UEP also provides a means to reconstruct the PDO/IPO multi-decadal variability of the Pacific Ocean as the low-pass filtered UEP displays multi-decadal variability that is consistent with the 20th century variability of the PDO and IPO. The UEP is then used to describe changes in ENSO variability which have occurred since 1650 focusing on changes in ENSOs variance, multi-year ENSO events, PDO-like multi-decadal variability and the effects of volcanic and solar forcing on ENSO. We find that multi-year El Niño events similar to the 1990–1995 event have occurred several times over the last 3 1/2 centuries. Consistent with earlier studies we find that volcanic forcing can induce a statistically significant change in the mean state of ENSO in the year of the eruption and a doubling of the probability of an El Niño (La Niña event occurring in the year of (three years after the eruption.

  12. Evaluating Ground-based Proxies for Solar Irradiance Variation

    Science.gov (United States)

    Oegerle, William (Technical Monitor); Jordan, Stuart

    2003-01-01

    In order to determine what ground-based proxies are best for evaluating solar irradiance variation before the advent of space observations, it is necessary to test these proxies against space observations. We have tested sunspot number, total sunspot area, and sunspot umbral area against the Nimbus-7 measurements of total solar irradiance variation cover the eleven year period 1980-1990. The umbral area yields the best correlation and the total sunspot area yields the poorest. Reasons for expecting the umbral area to yield the best correlation are given, the statistical procedure followed to obtain the results is described, and the value of determining the best proxy is discussed. The latter is based upon the availability of an excellent database from the Greenwich Observatory obtained over the period 1876-1976, which can be used to estimate the total solar irradiance variation before sensitive space observations were available. The ground-based observations used were obtained at the Coimbra Solar Observatory. The analysis was done at Goddard using these data and data from the Nimbus-7 satellite.

  13. Error characterization for asynchronous computations: Proxy equation approach

    Science.gov (United States)

    Sallai, Gabriella; Mittal, Ankita; Girimaji, Sharath

    2017-11-01

    Numerical techniques for asynchronous fluid flow simulations are currently under development to enable efficient utilization of massively parallel computers. These numerical approaches attempt to accurately solve time evolution of transport equations using spatial information at different time levels. The truncation error of asynchronous methods can be divided into two parts: delay dependent (EA) or asynchronous error and delay independent (ES) or synchronous error. The focus of this study is a specific asynchronous error mitigation technique called proxy-equation approach. The aim of this study is to examine these errors as a function of the characteristic wavelength of the solution. Mitigation of asynchronous effects requires that the asynchronous error be smaller than synchronous truncation error. For a simple convection-diffusion equation, proxy-equation error analysis identifies critical initial wave-number, λc. At smaller wave numbers, synchronous error are larger than asynchronous errors. We examine various approaches to increase the value of λc in order to improve the range of applicability of proxy-equation approach.

  14. High-resolution terrestrial GDGT data from the mid-Cretaceous: significant shifts in continental paleotemperatures (Invited)

    Science.gov (United States)

    Grocke, D. R.; Sinninghe Damsté, J. S.; Spicer, R. A.; Heimhofer, U.

    2010-12-01

    Understanding the terrestrial response to carbon cycle perturbations (i.e., oceanic anoxic events, OAEs) are critical for generating accurate, coupled ocean-atmosphere models. Oceanic geochemical data for the Cretaceous is becoming more prevalent and detailed, especially with organic geochemical proxies such as TEX86 (based on membrane lipids from marine Crenarchaeota). Previous research has identified OAE1d (Albian/Cenomanian boundary, ACB, Cretaceous) using carbon isotopes in terrestrial organic matter from Rose Creek Pit, Dakota Fm., Nebraska, USA [Gröcke et al. 2006]. A subsequent terrestrial carbon-isotope record has been produced from Moose River Basin, Ontario (Canada), which shows the complete OAE1d isotopic excursion in striking detail from an expanded lignite-mudstone facies (˜40m). A preliminary organic geochemical study of glycerol dialkyl glycerol tetraethers (GDGTs) from the Moose River Basin lignites has been conducted to test the validity of obtaining mean annual air temperature (MAAT), and suggests that it could prove to be a valuable method for extracting Cretaceous terrestrial temperatures. A detailed MAAT from Moose River Basin shows an increase of over 15°C over the ACB. Comparison with North Atlantic oceanic TEX86 and foraminifer oxygen-isotope records reveal a contradictory change in temperature over the ACB and a decrease in temperature of ˜2°C and ˜4°C respectively. However, these data all provide excellent correspondence to latitudinal GCM output for the Albian [Poulsen et al. 2007] for a simulated atmosphere with 8x pre-industrial pCO2 levels. Paleobotanical data suggest that these reconstructed continental paleotemperatures are supported. This preliminary data highlights the potential use of terrestrial GDGTs to generate palaeoclimatic data from the Cretaceous terrestrial system.

  15. Efficient Conditional Proxy Re-encryption with Chosen-Ciphertext Security

    NARCIS (Netherlands)

    Weng, Jiang; Yang, Yanjiang; Tang, Qiang; Deng, Robert H.; Bao, Feng

    Recently, a variant of proxy re-encryption, named conditional proxy re-encryption (C-PRE), has been introduced. Compared with traditional proxy re-encryption, C-PRE enables the delegator to implement fine-grained delegation of decryption rights, and thus is more useful in many applications. In this

  16. 17 CFR 240.14a-16 - Internet availability of proxy materials.

    Science.gov (United States)

    2010-04-01

    ... holder to access and review the proxy materials before voting; (3) The Internet Web site address where... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Internet availability of proxy... Under the Securities Exchange Act of 1934 Regulation 14a: Solicitation of Proxies § 240.14a-16 Internet...

  17. Remote Patron Validation: Posting a Proxy Server at the Digital Doorway.

    Science.gov (United States)

    Webster, Peter

    2002-01-01

    Discussion of remote access to library services focuses on proxy servers as a method for remote access, based on experiences at Saint Mary's University (Halifax). Topics include Internet protocol user validation; browser-directed proxies; server software proxies; vendor alternatives for validating remote users; and Internet security issues. (LRW)

  18. A novel salinity proxy based on Na incorporation into foraminiferal calcite

    NARCIS (Netherlands)

    Wit, J.C.; de Nooijer, L.J.; Wolthers, M.; Reichart, G.J.

    2013-01-01

    Salinity and temperature determine seawater density, and differences in both thereby control global thermohaline circulation. Whereas numerous proxies have been calibrated and applied to reconstruct temperature, a direct and independent proxy for salinity is still missing. Ideally, a new proxy for

  19. A Type-and-Identity-based Proxy Re-Encryption Scheme and its Application in Healthcare

    NARCIS (Netherlands)

    Ibraimi, L.; Tang, Qiang; Hartel, Pieter H.; Jonker, Willem

    2008-01-01

    Proxy re-encryption is a cryptographic primitive developed to delegate the decryption right from one party (the delegator) to another (the delegatee). In a proxy re-encryption scheme, the delegator assigns a key to a proxy to re-encrypt all messages encrypted with his public key such that the

  20. A procedure to correct proxy-reported weight in the National Health Interview Survey, 1976–2002

    Directory of Open Access Journals (Sweden)

    Utz Rebecca L

    2009-01-01

    Full Text Available Abstract Background Data from the National Health Interview Survey (NHIS show a larger-than-expected increase in mean BMI between 1996 and 1997. Proxy-reports of height and weight were discontinued as part of the 1997 NHIS redesign, suggesting that the sharp increase between 1996 and 1997 may be artifactual. Methods We merged NHIS data from 1976–2002 into a single database consisting of approximately 1.7 million adults aged 18 and over. The analysis consisted of two parts: First, we estimated the magnitude of BMI differences by reporting status (i.e., self-reported versus proxy-reported height and weight. Second, we developed a procedure to correct biases in BMI introduced by reporting status. Results Our analyses confirmed that proxy-reports of weight tended to be biased downward, with the degree of bias varying by race, sex, and other characteristics. We developed a correction procedure to minimize BMI underestimation associated with proxy-reporting, substantially reducing the larger-than-expected increase found in NHIS data between 1996 and 1997. Conclusion It is imperative that researchers who use reported estimates of height and weight think carefully about flaws in their data and how existing correction procedures might fail to account for them. The development of this particular correction procedure represents an important step toward improving the quality of BMI estimates in a widely used source of epidemiologic data.

  1. Impact of prehistoric cooking practices on paleoenvironmental proxies in shell midden constituents

    Science.gov (United States)

    Müller, Peter; Staudigel, Philip; Murray, Sean T.; Westphal, Hildegard; Swart, Peter K.

    2016-04-01

    Paleoenvironmental proxy records such as oxygen isotopes of calcareous skeletal structures like fish otoliths or mollusk shells provide highest-resolution information about environmental conditions experienced by the organism. Accumulations of such skeletal structures by ancient coastal populations in so called "shell midden" deposits provide us with sub-seasonally resolved paleoclimate records covering time spans up to several millennia. Given their high temporal resolution, these deposits are increasingly used for paleoclimate reconstructions and complement our understanding of ancient climate changes. However, gathered as comestibles, most of these skeletal remains were subject to prehistoric cooking methods prior to deposition. The associated alteration of the chemical proxy signatures as well as the subsequent error for paleoenvironmental reconstructions remained almost entirely neglected so far. Here, we present clumped isotope, conventional oxygen and carbon isotopes as well as element:Ca ratios measured in modern bivalve shells after exposing them to different prehistoric cooking methods. Our data show that most cooking methods considerably alter commonly used paleoclimate proxy systems which can lead to substantial misinterpretations of ancient climate conditions. Since the magnitude of chemical alteration is not distinguishable from natural temperature variability in most coastal settings, the alteration of shell midden constituents by prehistoric cooking remains likely unnoticed in most cases. Thus, depending on the cooking method, pre-depositional heating might have introduced considerable errors into previous paleoclimate studies. However, our data also show that clumped isotope thermometry represents a suitable diagnostic tool to detect such pre-depositional cooking events and also allows differentiating between the most commonly applied prehistoric cooking methods.

  2. Talking with TV shows

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Laursen, Ditte

    2014-01-01

    User interaction with radio and television programmes is not a new thing. However, with new cross-media production concepts such as X Factor and Voice, this is changing dramatically. The second-screen logic of these productions encourages viewers, along with TV’s traditional one-way communication...... mode, to communicate on interactive (dialogue-enabling) devices such as laptops, smartphones and tablets. Using the TV show Voice as our example, this article shows how the technological and situational set-up of the production invites viewers to engage in new ways of interaction and communication....... More specifically, the article demonstrates how online comments posted on the day of Voice’s 2012 season finale can be grouped into four basic action types: (1) Invitation to consume content, (2) Request for participation, (3) Request for collaboration and (4) Online commenting. These action types...

  3. Um show de cacau

    OpenAIRE

    Rezende, José Francisco; UNIGRANRIO / PPGA; Mello, Simone; UNIGRANRIO

    2016-01-01

    O caso de ensino apresenta a trajetória de Alexandre Tadeu da Costa e da chocolateria Cacau Show. Seu objetivo é levar os estudantes a identificar alternativas e tomar decisões sobre posicionamento para continuidade do desenvolvimento de vantagens competitivas, sustentação de competência logística e possíveis abordagens ao mercado externo. 

  4. Taking in a Show.

    Science.gov (United States)

    Boden, Timothy W

    2016-01-01

    Many medical practices have cut back on education and staff development expenses, especially those costs associated with conventions and conferences. But there are hard-to-value returns on your investment in these live events--beyond the obvious benefits of acquired knowledge and skills. Major vendors still exhibit their services and wares at many events, and the exhibit hall is a treasure-house of information and resources for the savvy physician or administrator. Make and stick to a purposeful plan to exploit the trade show. You can compare products, gain new insights and ideas, and even negotiate better deals with representatives anxious to realize returns on their exhibition investments.

  5. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  6. Rare earth elements in Holocene reefal microbialites: a new shallow seawater proxy

    Science.gov (United States)

    Webb, Gregory E.; Kamber, Balz S.

    2000-05-01

    The concentration of rare earth elements and yttrium (REE + Y) was determined in Holocene Mg-calcite microbialites from shallow reef framework cavities at Heron Reef, Great Barrier Reef. Shale-normalized REE + Y patterns of 52 microbialite samples show: (1) uniform heavy REE enrichment (Nd SN/Yb SN = 0.236, SD = 0.026); (2) consistent negative Ce and positive La anomalies; (3) marine Y/Ho ratios (56.17, SD = 2.66); and (4) slightly positive Gd anomalies. All of these features are consistent with the geochemistry of well-oxygenated, shallow ambient seawater. REE partition coefficients were calculated relative to shallow Coral Sea seawater. They are uniform (relative SD = 10.2%) across the entire mass range and almost two orders of magnitude higher than those between coral and seawater. Hence, terrigenous detritus-free, modern microbialites are a more reliable proxy for seawater REE chemistry than are skeletal carbonates. Ancient limestones have been considered largely problematic as sources for REE proxies owing to perceived problems with diagenesis, partly on the basis of relatively high REE concentrations in some limestones compared to modern skeletal carbonates. However, high REE concentrations in modern microbialites suggest that ancient limestones with relatively high REE concentrations, if not contaminated by terrigenous detritus, may reflect original seawater chemistry. Terrigenous contamination, if present, is readily detectable on the basis of co-occurring trace element concentrations (Sc, Hf, Th) and Y/Ho ratio. Hence, ancient, particularly reefal, limestones may provide reliable seawater REE proxies. The occurrence of microbialites in clean limestones as old as 3.5 Ga suggests the possibility of reconstructing shallow marine REE chemistry over most of Earth history with important implications for paleogeography and paleoredox studies.

  7. Towards a new proxy of continental atmospheric humidity: the triple oxygen isotopic composition of plant biosilica

    Science.gov (United States)

    Alexandre, A. E.; Pauchet, S.; Landais, A.; Piel, C.; Devidal, S.; Roy, J.; Vallet-Coulomb, C.; Sonzogni, C.; Pasturel, M.; Cornuault, P.; Xin, J.; Mazur, J. C.; Prie, F.; Bentaleb, I.

    2016-12-01

    There is a serious lack of proxy suitable for reconstructing, in a quantitative way, past changes of continental atmospheric humidity. This reduces the possibility to make model-data comparisons necessary for the implementation of climate models. Over the past 10 years, analytical developments have enabled a few laboratories to reach sufficient precision for measuring the triple oxygen isotopes, expressed by the 17O-excess, in water, water vapor, atmospheric oxygen, and minerals. The 17O-excess represents an alternative to d-excess for investigating relative humidity conditions that prevail during water evaporation. The 17O-excess of water results from the increase of kinetic isotopic fractionation at evaporative sites as a function of decreasing relative humidity. This mechanism occurs at large scales, i.e. during seawater evaporation or during plant canopies transpiration. Unlike deuterium-excess, 17O-excess is supposed to be insensitive to temperature and less sensitive than δD and δ18O to equilibrium fractionation during transport and precipitation. Additionally, the 17O-excess is recorded in biogenic minerals less prone to weathering than organic compounds. Here, we calibrate the 17O-excess of plant biosilica as a new air humidity proxy. First, we examined the behavior of the 17O-excess in soil water, leaf water and phytoliths in growth chambers in response to changes in relative humidity. Second, we measured the 17O-excess of soil phytolith assemblages from inter-tropical savannas and forests distributed along humidity transects. Both approaches show similar dependency of phytolith 17O-excess to relative humidity. The results allow to discuss future calibration directions aimed at estimating the precision of the obtained relationship and at quantifying the successive isotopic fractionations in play at the soil-plant-atmosphere interface, to provide a strong proxy of past atmospheric relative humidity.

  8. How to combine sparse proxy data and coupled climate models

    Science.gov (United States)

    Paul, André; Schäfer-Neth, Christian

    2005-04-01

    We address the problem of reconstructing a global field from proxy data with sparse spatial sampling such as the MARGO (multi-proxy approach for the reconstruction of the glacial ocean surface) SST (sea-surface temperature) and δ18O c (oxygen-18/oxygen-16 isotope ratio preserved in fossil carbonate shells of planktic foraminifera) data. To this end, we propose to `assimilate' these data into coupled climate models by adjusting some of their parameters and optimizing the fit. In particular, we suggest to combine a forward model and an objective function that quantifies the misfit to the data. Because of their computational efficiency, earth system models of intermediate complexity are particularly well-suited for this purpose. We used one such model (the University of Victoria Earth System Climate Model) and carried out a series of sensitivity experiments by varying a single model parameter through changing the atmospheric CO2 concentration. The unanalyzed World Ocean Atlas SST and the observed sea-ice concentration served as present-day targets. The sparse data coverage as implied by the locations of 756 ocean sediment cores from the MARGO SST database was indeed sufficient to determine the best fit. As anticipated, it turned out to be the 365 ppm experiment. We also found that the 200 ppm experiment came surprisingly close to what is commonly expected for the Last Glacial Maximum ocean circulation. Our strategy has a number of advantages over more traditional mapping methods, e.g., there is no need to force the results of different proxies into a single map, because they can be compared to the model output one at a time, properly taking into account the different seasons of plankton growth or varying depth habitats. It can be extended to more model parameters and even be automated.

  9. Patient-rated versus proxy-rated cognitive and functional measures in older adults

    Science.gov (United States)

    Howland, Molly; Allan, Kevin C; Carlton, Caitlin E; Tatsuoka, Curtis; Smyth, Kathleen A; Sajatovic, Martha

    2017-01-01

    Objectives Patients with cognitive impairment may have difficulty reporting their functional and cognitive abilities, which are important clinical outcomes. Health care proxies may be able to corroborate patient self-reports. Several studies reported discrepancy between patient and proxy ratings, though the literature is sparse on changes over time of these ratings. Our goals in this 12-month study were to compare patient and proxy reports on functioning, cognition, and everyday executive function, and to further elucidate correlates of patient–proxy discrepancy. Methods This was a prospective cohort study of individuals older than 70 years who ranged from having no cognitive impairment to having moderate dementia who had a proxy available to complete instruments at baseline (N=76). Measurements included Alzheimer’s Disease Cooperative Study–Activities of Daily Living Inventory (ADCS-ADLI), Neuro-QOL Executive Function, PROMIS Applied Cognition (PROMIS-Cog), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale. Results Patient- and proxy-rated ADCS-ADLI were correlated at baseline and at 1-year follow-up. Patient and proxy ratings were discrepant on Neuro-QOL Executive Function and PROMIS-Cog. Greater patient–proxy discrepancy on PROMIS-Cog was associated with younger age and less depression, and greater patient–proxy discrepancy on Neuro-QOL Executive Function was associated with less depression and worse cognitive impairment. Patient–proxy discrepancy increased over time for everyday executive function. Changes in proxy-rated but not patient-rated ADCS-ADLI correlated with MMSE changes. Conclusion Patients and proxies generally agree in reporting on activities of daily living. Patient and proxy reports differ in their respective evaluation of cognitive functioning and everyday executive function. Ratings from both sources may be preferred for these two domains, though studies using gold standard measures are necessary. It is important

  10. Red is not a proxy signal for female genitalia in humans.

    Directory of Open Access Journals (Sweden)

    Sarah E Johns

    Full Text Available Red is a colour that induces physiological and psychological effects in humans, affecting competitive and sporting success, signalling and enhancing male social dominance. The colour is also associated with increased sexual attractiveness, such that women associated with red objects or contexts are regarded as more desirable. It has been proposed that human males have a biological predisposition towards the colour red such that it is 'sexually salient'. This hypothesis argues that women use the colour red to announce impending ovulation and sexual proceptivity, with this functioning as a proxy signal for genital colour, and that men show increased attraction in consequence. In the first test of this hypothesis, we show that contrary to the hypothesis, heterosexual men did not prefer redder female genitalia and, by extension, that red is not a proxy signal for genital colour. We found a relative preference for pinker genital images with redder genitalia rated significantly less sexually attractive. This effect was independent of raters' prior sexual experience and variation in female genital morphology. Our results refute the hypothesis that men's attraction to red is linked to an implied relationship to genital colour and women's signalling of fertility and sexual proceptivity.

  11. Red is not a proxy signal for female genitalia in humans.

    Science.gov (United States)

    Johns, Sarah E; Hargrave, Lucy A; Newton-Fisher, Nicholas E

    2012-01-01

    Red is a colour that induces physiological and psychological effects in humans, affecting competitive and sporting success, signalling and enhancing male social dominance. The colour is also associated with increased sexual attractiveness, such that women associated with red objects or contexts are regarded as more desirable. It has been proposed that human males have a biological predisposition towards the colour red such that it is 'sexually salient'. This hypothesis argues that women use the colour red to announce impending ovulation and sexual proceptivity, with this functioning as a proxy signal for genital colour, and that men show increased attraction in consequence. In the first test of this hypothesis, we show that contrary to the hypothesis, heterosexual men did not prefer redder female genitalia and, by extension, that red is not a proxy signal for genital colour. We found a relative preference for pinker genital images with redder genitalia rated significantly less sexually attractive. This effect was independent of raters' prior sexual experience and variation in female genital morphology. Our results refute the hypothesis that men's attraction to red is linked to an implied relationship to genital colour and women's signalling of fertility and sexual proceptivity.

  12. Tycho 2: A Proxy Application for Kinetic Transport Sweeps

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, Charles Kristopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division; Warsa, James S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division

    2016-09-14

    Tycho 2 is a proxy application that implements discrete ordinates (SN) kinetic transport sweeps on unstructured, 3D, tetrahedral meshes. It has been designed to be small and require minimal dependencies to make collaboration and experimentation as easy as possible. Tycho 2 has been released as open source software. The software is currently in a beta release with plans for a stable release (version 1.0) before the end of the year. The code is parallelized via MPI across spatial cells and OpenMP across angles. Currently, several parallelization algorithms are implemented.

  13. Nursing interventions in Münchausen syndrome by proxy.

    Science.gov (United States)

    Volz, A G

    1995-09-01

    1. Münchausen syndrome by proxy is a rare but serious and potentially lethal form of child abuse in which a primary care giver induces or reports factitious symptoms in a child. 2. The child suffers from the caregiver's actions and health care providers unknowingly become accomplices when they provide unnecessary testing and therapies. 3. The child's physical and psychological welfare can be protected through the efforts of the forensic nurse specialist coordinating a multidisciplinary health care team's work to detect the syndrome and intervene early on.

  14. Compliance with treatment in asthma and Munchausen syndrome by proxy.

    Science.gov (United States)

    Godding, V; Kruth, M

    1991-01-01

    Among 1648 asthmatic patients, 17 families (1%) were identified as having Munchausen syndrome by proxy. Ten families did not treat their children's, attacks or refused medical care, and seven exaggerated the severity of symptoms to obtain invasive investigations and treatment. All the families had disturbed psychosocial backgrounds. The abuse consisted mainly of neglect, in that necessary treatment was not given. In some cases a more direct form of abuse was observed, when useless and sometimes harmful investigations and treatment were given. We conclude that medical control of the compliance of both parents and children is necessary in the management of childhood asthma. PMID:1929492

  15. Investigating genetic loci that encode plant-derived paleoclimate proxies

    Science.gov (United States)

    Bender, A. L. D.; Suess, M.; Chitwood, D. H.; Bradley, A. S.

    2016-12-01

    Long chain (>C25) n-alkanes in sediments predominantly derive from terrestrial plant waxes. Hydrogen isotope ratios (δD) of leaf wax hydrocarbons correlate with δDH2O of precipitation and are commonly used as paleoclimate proxies. However, biological variability in the isotopic fractionations between water and plant materials also affects the n-alkane δD values. Correct interpretation of this paleoclimate proxy requires that we resolve genetic and environmental effects. Genetic variability underlying differences in leaf wax structure and isotopic composition can be quantitatively determined through the use of model organisms. Interfertile Solanum sect. Lycopersicon (tomato) species provide an ideal model species complex for this approach. We used a set of 76 precisely defined near-isogenic lines (introgression lines [ILs]) in which small genomic regions from the wild tomato relative Solanum pennellii have been introduced into the genome of the domestic tomato, S. lycopersicum. By characterizing quantitative traits of these ILs (leaf wax structure and isotopic composition), we can resolve the degree to which each trait is regulated by genetic versus environmental factors. We present data from two growth experiments conducted with all 76 ILs. In this study, we quantify leaf wax traits, including δD values, δ13C values, and structural metrics including the methylation index (a variable that describes the ratio of iso­- and anteiso- to n-alkanes). Among ILs, δD values vary by up to 35‰ and 60‰ for C31 and C33 n-alkanes, respectively. Many ILs have methylation indices that are discernably different from the parent domesticated tomato (p < 0.001), which suggests that methylation is a highly polygenic trait. This pattern is similar to the genetics that control leaf shape, another trait commonly used as a paleoclimate proxy. Based on our preliminary analysis, we propose candidate genes that control aspects of plant physiology that affect these quantitative

  16. The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

    Science.gov (United States)

    Slotznick, Sarah P.; Eiler, John M.; Fischer, Woodward W.

    2018-03-01

    utilized. The presence of diagenetic iron carbonates in many samples severely affected the proxy even at low grade, engendering an interpretation of ferruginous conditions in all lithologies, but particularly in carbonate-bearing rocks. Increasing metamorphic grades transformed iron in carbonates into iron in silicate minerals, which when combined with a slight increase in the amount of pyrrhotite, drove the proxy toward more oxic and more euxinic conditions. Broad-classes of metamorphic reactions (e.g. decarbonation, silicate formation) occurred at distinct temperatures-pressures in carbonates versus siliciclastics, and could be either abrupt between metamorphic facies or more gradual in nature. Notably, these analyses highlighted the importance of trace iron in phases like calcite, which otherwise might not be included in iron-focused research i.e. ore-system petrogenesis, metamorphic evolution, or normative calculations of mineral abundance. The observations show that iron is mobile and reactive during diagenesis and metamorphism, and these post-depositional processes can readily overprint primary redox information held by iron speciation. However, in principle, additional mineralogical and petrographic approaches can be combined with iron speciation data to help untangle many of these post-depositional processes and arrive at more accurate estimates of paleoenvironmental redox conditions and processes, even for metamorphosed samples.

  17. Comfort with proxy consent to research involving decisionally impaired older adults: do type of proxy and risk-benefit profile matter?

    Science.gov (United States)

    Dubois, Marie-France; Bravo, Gina; Graham, Janice; Wildeman, Sheila; Cohen, Carole; Painter, Karen; Bellemare, Suzanne

    2011-11-01

    Dementia research often requires the participation of people with dementia. Obtaining informed consent is problematic when potential participants lack the capacity to provide it. We investigated comfort with proxy consent to research involving older adults deemed incapable of this decision, and examined if comfort varies with the type of proxy and the study's risk-benefit profile. We surveyed random samples of five relevant groups (older adults, informal caregivers, physicians, researchers in aging, and Research Ethics Board members) from four Canadian provinces. Respondents were presented with scenarios involving four types of proxies (non-assigned, designated in a healthcare advance directive with or without instructions specific to research participation, and court-appointed). Given a series of risk-benefit profiles, respondents indicated whether they were comfortable with proxy consent to research for each scenario. Two percent of the respondents felt proxy consent should never be allowed. In all groups, comfort depended far more on the risk-benefit profile associated with the research scenario than with type of proxy. For research involving little or no risk and potential personal benefits, over 90% of the respondents felt comfortable with substitute consent by a designated or court-appointed proxy while 80% were at ease with a non-assigned proxy. For studies involving serious risks with potentially greater personal benefits, older adults and informal caregivers were less comfortable with proxy consent. A large majority of Canadians are comfortable with proxy consent for low-risk research. Further work is needed to establish what kinds of research are considered to be low risk.

  18. Thermodynamic Proxies to Compensate for Biases in Drug Discovery Methods.

    Science.gov (United States)

    Ekins, Sean; Litterman, Nadia K; Lipinski, Christopher A; Bunin, Barry A

    2016-01-01

    We propose a framework with simple proxies to dissect the relative energy contributions responsible for standard drug discovery binding activity. We explore a rule of thumb using hydrogen-bond donors, hydrogen-bond acceptors and rotatable bonds as relative proxies for the thermodynamic terms. We apply this methodology to several datasets (e.g., multiple small molecules profiled against kinases, Mycobacterium tuberculosis (Mtb) high throughput screening (HTS) and structure based drug design (SBDD) derived compounds, and FDA approved drugs). We found that Mtb active compounds developed through SBDD methods had statistically significantly larger PEnthalpy values than HTS derived compounds, suggesting these compounds had relatively more hydrogen bond donor and hydrogen bond acceptors compared to rotatable bonds. In recent FDA approved medicines we found that compounds identified via target-based approaches had a more balanced enthalpic relationship between these descriptors compared to compounds identified via phenotypic screens As it is common to experimentally optimize directly for total binding energy, these computational methods provide alternative calculations and approaches useful for compound optimization alongside other common metrics in available software and databases.

  19. Simulation of Wake Vortex Radiometric Detection via Jet Exhaust Proxy

    Science.gov (United States)

    Daniels, Taumi S.

    2015-01-01

    This paper describes an analysis of the potential of an airborne hyperspectral imaging IR instrument to infer wake vortices via turbine jet exhaust as a proxy. The goal was to determine the requirements for an imaging spectrometer or radiometer to effectively detect the exhaust plume, and by inference, the location of the wake vortices. The effort examines the gas spectroscopy of the various major constituents of turbine jet exhaust and their contributions to the modeled detectable radiance. Initially, a theoretical analysis of wake vortex proxy detection by thermal radiation was realized in a series of simulations. The first stage used the SLAB plume model to simulate turbine jet exhaust plume characteristics, including exhaust gas transport dynamics and concentrations. The second stage used these plume characteristics as input to the Line By Line Radiative Transfer Model (LBLRTM) to simulate responses from both an imaging IR hyperspectral spectrometer or radiometer. These numerical simulations generated thermal imagery that was compared with previously reported wake vortex temperature data. This research is a continuation of an effort to specify the requirements for an imaging IR spectrometer or radiometer to make wake vortex measurements. Results of the two-stage simulation will be reported, including instrument specifications for wake vortex thermal detection. These results will be compared with previously reported results for IR imaging spectrometer performance.

  20. Attribute-based proxy re-encryption with keyword search.

    Directory of Open Access Journals (Sweden)

    Yanfeng Shi

    Full Text Available Keyword search on encrypted data allows one to issue the search token and conduct search operations on encrypted data while still preserving keyword privacy. In the present paper, we consider the keyword search problem further and introduce a novel notion called attribute-based proxy re-encryption with keyword search (ABRKS, which introduces a promising feature: In addition to supporting keyword search on encrypted data, it enables data owners to delegate the keyword search capability to some other data users complying with the specific access control policy. To be specific, ABRKS allows (i the data owner to outsource his encrypted data to the cloud and then ask the cloud to conduct keyword search on outsourced encrypted data with the given search token, and (ii the data owner to delegate other data users keyword search capability in the fine-grained access control manner through allowing the cloud to re-encrypted stored encrypted data with a re-encrypted data (embedding with some form of access control policy. We formalize the syntax and security definitions for ABRKS, and propose two concrete constructions for ABRKS: key-policy ABRKS and ciphertext-policy ABRKS. In the nutshell, our constructions can be treated as the integration of technologies in the fields of attribute-based cryptography and proxy re-encryption cryptography.

  1. A high-resolution multi-proxy record of late Cenozoic environment change from central Taklimakan Desert, China

    OpenAIRE

    X Wang; Sun, D. H.; Wang, F; Li, B F; Wu, S.; Guo, F.; Li, Z. J.; Zhang, Y. B.; F. H. Chen

    2013-01-01

    The Taklimakan Desert in the Tarim Basin is the largest desert in Central Asia, and is regarded as one of the main dust sources to the Northern Hemisphere. Late Cenozoic sedimentary sequences with intercalated in-situ aeolian dune sands in this area preserve direct evidence for the Asian desertification. Herein, we report a high-resolution multi-proxy climatic record from the precise magnetostratigraphic dated Hongbaishan section in the central Taklimakan Desert. Our results show that ...

  2. Territory occupancy and parental quality as proxies for spatial prioritization of conservation areas.

    Directory of Open Access Journals (Sweden)

    Matthias Tschumi

    Full Text Available In order to maximize their fitness, individuals aim at choosing territories offering the most appropriate combination of resources. As population size fluctuates in time, the frequency of breeding territory occupancy reflects territory quality. We investigated the relationships between the frequency of territory occupancy (2002-2009 vs. habitat characteristics, prey abundance, reproductive success and parental traits in hoopoes Upupa epops L., with the objective to define proxies for the delineation of conservation priority areas. We predicted that the distribution of phenotypes is despotic and sought for phenotypic characteristics expressing dominance. Our findings support the hypothesis of a despotic distribution. Territory selection was non-random: frequently occupied territories were settled earlier in the season and yielded higher annual reproductive success, but the frequency of territory occupancy could not be related to any habitat characteristics. Males found in frequently occupied territories showed traits expressing dominance (i.e. larger body size and mass, and older age. In contrast, morphological traits of females were not related to the frequency of territory occupancy, suggesting that territory selection and maintenance were essentially a male's task. Settlement time in spring, reproductive success achieved in a given territory, as well as phenotypic traits and age of male territory holders reflected territory quality, providing good proxies for assessing priority areas for conservation management.

  3. Is profitability a good proxy for efficiency? Evidence from the subsector of tour operators

    Directory of Open Access Journals (Sweden)

    Hedija Veronika

    2017-12-01

    Full Text Available The goal of the paper is to evaluate the economic efficiency of tour operators in the Czech Republic in the period 2007-2014 using data envelopment analysis (DEA models and prove the link between economic efficiency and profitability and to find out if profitability is a good proxy for economic efficiency. Data was exported from the database Albertina CZ Gold Edition. We calculated the efficiency score using CCR (Charnes, Cooper and Rhodes and BCC (Banker, Charnes and Cooper models based on 3 inputs and 1 output. In the years 2007 to 2010, the efficiency score of almost all the companies was higher than 0.5; however, in years since 2011, we revealed significant differences in the efficiency of individual firms and only about 40 percent of tour operators achieved an efficiency score higher than 0.5. Using Pearson and Spearman correlation coefficients, our findings show that, in the case of the Czech tour operator market, profitability ratios do not correspond with firm efficiency. Profitability ratios are not a good proxy for economic efficiency and should not be used as the only firm criterion of performance.

  4. Planktonic foraminiferal rare earth elements as a potential new aeolian dust proxy

    Science.gov (United States)

    Chou, C.; Liu, Y.; Lo, L.; Wei, K.; Shen, C.

    2012-12-01

    Characteristics of rare earth elements (REEs) have widely been used as important tracers in many fields of earth sciences, including lithosphere research, environmental change, ocean circulation and other natural carbonate materials. Foraminiferal test REE signatures have been suggested to reflect ambient seawater conditions and serve as valuable proxies in the fields of paleoceanography and paleoclimate. Here we present a 60-kyr planktonic foraminifera Globigerinoides ruber (white, 250-300 μm) REE record of a sediment core MD05-2925 (9°20.61'S, 151°27.61'E, water depth 1660 m) from the Solomon Sea. The REE diagram shows two dominant sources of local seawater and nearby terrestrial input. The variability of foraminiferal REE/Ca time series is different from Mg/Ca-inferred sea surface temperature and δ18O records during the past 60-kyr. This inconsistency suggests that planktonic foraminiferal REE content cannot result only from changes in ice volume and temperature. Synchroneity between high planktonic foraminiferal REE content and Antarctic ice core dust amount record implies the same dust sources, probably from Australia or mainland China. Our results suggest that foraminiferal REE can potentially be as a new dust proxy and record dry/humid conditions at the source area.

  5. Territory occupancy and parental quality as proxies for spatial prioritization of conservation areas.

    Science.gov (United States)

    Tschumi, Matthias; Schaub, Michael; Arlettaz, Raphaël

    2014-01-01

    In order to maximize their fitness, individuals aim at choosing territories offering the most appropriate combination of resources. As population size fluctuates in time, the frequency of breeding territory occupancy reflects territory quality. We investigated the relationships between the frequency of territory occupancy (2002-2009) vs. habitat characteristics, prey abundance, reproductive success and parental traits in hoopoes Upupa epops L., with the objective to define proxies for the delineation of conservation priority areas. We predicted that the distribution of phenotypes is despotic and sought for phenotypic characteristics expressing dominance. Our findings support the hypothesis of a despotic distribution. Territory selection was non-random: frequently occupied territories were settled earlier in the season and yielded higher annual reproductive success, but the frequency of territory occupancy could not be related to any habitat characteristics. Males found in frequently occupied territories showed traits expressing dominance (i.e. larger body size and mass, and older age). In contrast, morphological traits of females were not related to the frequency of territory occupancy, suggesting that territory selection and maintenance were essentially a male's task. Settlement time in spring, reproductive success achieved in a given territory, as well as phenotypic traits and age of male territory holders reflected territory quality, providing good proxies for assessing priority areas for conservation management.

  6. Design and Implementation of a Mobile Voting System Using a Novel Oblivious and Proxy Signature

    Directory of Open Access Journals (Sweden)

    Shin-Yan Chiou

    2017-01-01

    Full Text Available Electronic voting systems can make the voting process much more convenient. However, in such systems, if a server signs blank votes before users vote, it may cause undue multivoting. Furthermore, if users vote before the signing of the server, voting information will be leaked to the server and may be compromised. Blind signatures could be used to prevent leaking voting information from the server; however, malicious users could produce noncandidate signatures for illegal usage at that time or in the future. To overcome these problems, this paper proposes a novel oblivious signature scheme with a proxy signature function to satisfy security requirements such as information protection, personal privacy, and message verification and to ensure that no one can cheat other users (including the server. We propose an electronic voting system based on the proposed oblivious and proxy signature scheme and implement this scheme in a smartphone application to allow users to vote securely and conveniently. Security analyses and performance comparisons are provided to show the capability and efficiency of the proposed scheme.

  7. A case of Munchausen syndrome by proxy with subsequent suicide of the mother.

    Science.gov (United States)

    Vennemann, B; Perdekamp, M Grosse; Weinmann, W; Faller-Marquardt, M; Pollak, S; Brandis, M

    2006-05-10

    Munchausen syndrome by proxy is a subtle and difficult to diagnose form of child abuse in which the carer (usually the mother) simulates, manipulates or produces symptoms of illness in the victim. In most cases the detrimental effect is caused by applying foreign substances or by airway obstruction. In the presented case a 20-month-old girl developed a spreading soft-tissue infection resistant to treatment on the left upper arm after vaccination, which required a number of surgical interventions. Repeatedly, microorganisms from the intestinal flora were isolated from the wound secretion. After the girl suffered respiratory and circulatory arrest, which required resuscitation measures, chemical toxicological tests revealed not medically prescribed benzodiazepines in serum and urine. When the mother, a trained nurse, was confronted with the allegation to have manipulated the symptoms of the illness she committed suicide. The forensic autopsy of the suicide produced numerous hints suggesting chronic self-damaging behaviour described as Munchausen syndrome. This case shows a number of manipulation forms with the maintenance of a chronic skin and soft tissue infection belonging to the rarer forms of inflicting damage to the child. It also illustrates that confrontation with the allegation of Munchausen syndrome by proxy creates a very stressful emotional situation that may lead to a suicidal act.

  8. Prompt Proxy Mapping of Flood Damaged Rice Fields Using MODIS-Derived Indices

    Directory of Open Access Journals (Sweden)

    Youngjoo Kwak

    2015-11-01

    Full Text Available Flood mapping, particularly hazard and risk mapping, is an imperative process and a fundamental part of emergency response and risk management. This paper aims to produce a flood risk proxy map of damaged rice fields over the whole of Bangladesh, where monsoon river floods are dominant and frequent, affecting over 80% of the total population. This proxy risk map was developed to meet the request of the government on a national level. This study represents a rapid, straightforward methodology for estimating rice-crop damage in flood areas of Bangladesh during the large flood from July to September 2007, despite the lack of primary data. We improved a water detection algorithm to achieve a better discrimination capacity to discern flood areas by using a modified land surface water index (MLSWI. Then, rice fields were estimated utilizing a hybrid rice field map from land-cover classification and MODIS-derived indices, such as the normalized difference vegetation index (NDVI and enhanced vegetation index (EVI. The results showed that the developed method is capable of providing instant, comprehensive, nationwide mapping of flood risks, such as rice field damage. The detected flood areas and damaged rice fields during the 2007 flood were verified by comparing them with the Advanced Land Observing Satellite (ALOS AVNIR-2 images (a 10 m spatial resolution and in situ field survey data with moderate agreement (K = 0.57.

  9. Constraints in the application of the Branched and Isoprenoid Tetraether index as a terrestrial input proxy

    Science.gov (United States)

    Fietz, Susanne; MartíNez-Garcia, Alfredo; Huguet, Carme; Rueda, Gemma; Rosell-Melé, Antoni

    2011-10-01

    Determination of the relative inputs of aquatic autochthonous and terrestrial allochthonous organic matter into marine and lacustrine environments is essential to understanding the global carbon budget. A variety of proxies are used for this purpose, including the Branched and Isoprenoid Tetraether (BIT) index. This is calculated from the concentrations of branched glycerol dialkyl glycerol tetraethers (GDGTs), derived from unidentified terrestrial bacteria, and crenarchaeol, a marker for aquatic mesophile Thaumarchaeota (Crenarchaeota group I). As the index is a ratio, its value depends on both the crenarchaeol aquatic in situ production and the soil-derived branched GDGT input. Therefore, the BIT index reflects not only changes in the input of terrestrial or soil organic matter but also relative variations in aquatic Thaumarchaeota abundance in the water column. In fact, we show that in oceanic and lacustrine settings, the BIT index can be dominated by the aquatic end-member of the ratio. Consequently, the BIT index by itself can be an unreliable proxy to compare the input of terrestrial matter between sites and over time, and we propose that the quantification of branched GDGT fluxes or concentrations may instead be a better indicator of soil terrestrial inputs.

  10. Sulfur in foraminiferal calcite as a potential proxy for seawater carbonate ion concentration

    Science.gov (United States)

    van Dijk, I.; de Nooijer, L. J.; Boer, W.; Reichart, G.-J.

    2017-07-01

    Sulfur (S) incorporation in foraminiferal shells is hypothesized to change with carbonate ion concentration [CO32-], due to substitution of sulfate for carbonate ions in the calcite crystal lattice. Hence S/Ca values of foraminiferal carbonate shells are expected to reflect sea water carbonate chemistry. To generate a proxy calibration linking the incorporation of S into foraminiferal calcite to carbonate chemistry, we cultured juvenile clones of the larger benthic species Amphistegina gibbosa and Sorites marginalis over a 350-1200 ppm range of pCO2 values, corresponding to a range in [CO32-] of 93 to 211 μmol/kg. We also investigated the potential effect of salinity on S incorporation by culturing juvenile Amphistegina lessonii over a large salinity gradient (25-45). Results show S/CaCALCITE is not impacted by salinity, but increases with increasing pCO2 (and thus decreasing [CO32-] and pH), indicating S incorporation may be used as a proxy for [CO32-]. Higher S incorporation in high-Mg species S. marginalis suggests a superimposed biomineralization effect on the incorporation of S. Microprobe imaging reveals co-occurring banding of Mg and S in Amphistegina lessonii, which is in line with a strong biological control and might explain higher S incorporation in high Mg species. Provided a species-specific calibration is available, foraminiferal S/Ca values might add a valuable new tool for reconstructing past ocean carbonate chemistry.

  11. A multiproxy approach to reconstruct the climate and environmental changes during Holocene in Urmia Lake (NW-Iran)

    Science.gov (United States)

    Haghipour, Negar; McIntyre, Cameron; Darvish Khatooni, Javad; Hunziker, Daniela; Mohammadi, Ali; Eglinton, Timothy

    2017-04-01

    Lake Urmia, in northwest Iran, is the largest saline lake in the Middle East with surface area of 5000Km2. Despite its potential as an archive of paleo-climate and paleo-environmental information, to date there has been no molecular organic geochemical investigation or precise dating of these sediments, especially for the Holocene period. Several proxies in sediment cores from eastern and western parts of Urmia Lake have been used in this study to produce a more reliable picture of climate and environmental changes during the Holocene. We present data on both geochemical proxies and sediment lipid biomarkers on two cores from different parts of the Lake. The age model based on 60 calibrated radiocarbon dates shows variation of sedimentation rates between early and middle Holocene and a sudden increase in late Holocene. This is interpreted as a sudden event associated to mass movement. Results on bulk measurements (TOC, δ13C and C/N) give evidence for a warmer and wetter climate between 0.5 and 3 kyr BP. Phytoplankton biomarkers were most abundant in this period, indicating high phytoplankton productivity. This period was followed by a relatively cooler and drier episode between 3.5 and 7Kyr BP., decrease in phytoplankton productivity indicating cooler climate and showing terrestrial signal. The coolest and drier conditions occurred between 7-10.3 Kyr BP. This is in agreement with compound-specific leaf wax hydrogen isotopes and TEX86 proxy in GDGTs.

  12. Analysis of Forgery Attack on One-Time Proxy Signature and the Improvement

    Science.gov (United States)

    Wang, Tian-Yin; Wei, Zong-Li

    2016-02-01

    In a recent paper, Yang et al. (Quant. Inf. Process. 13(9), 2007-2016, 2014) analyzed the security of one-time proxy signature scheme Wang and Wei (Quant. Inf. Process. 11(2), 455-463, 2012) and pointed out that it cannot satisfy the security requirements of unforgeability and undeniability because an eavesdropper Eve can forge a valid proxy signature on a message chosen by herself. However, we find that the so-called proxy message-signature pair forged by Eve is issued by the proxy signer in fact, and anybody can obtain it as a requester, which means that the forgery attack is not considered as a successful attack. Therefore, the conclusion that this scheme cannot satisfy the security requirements of proxy signature against forging and denying is not appropriate in this sense. Finally, we study the reason for the misunderstanding and clarify the security requirements for proxy signatures.

  13. Munchausen Syndrome by proxy: Definition, context, and psychological factors involved

    Directory of Open Access Journals (Sweden)

    Thomas Gomes Gonçalves

    2014-07-01

    Full Text Available The Munchausen syndrome by proxy refers to a pathology characterized by physical and emotional abuse in which the simulation or production of symptoms is directed towards a child, which involves taking him or her to health treatments and unnecessary surgeries. The difficulties in the diagnosis of this form of abuse and the emotional aspects involved highlight the destructive effects in the infancy subjectivity due to the lack of loving capacity protecting and prioritizing the child demands. Psychoanalysis offers a differentiated view, comprehending that the mother attempts to elaborate her own psychic conflicts by the repetition of traumatic experience. There is a necessity of comprehension of the instinct destructivity presented in the maternal unconscious dynamics revealed in the modality of caring which is reflected in violence.

  14. Obesity as a Presentation of Munchausen Syndrome by Proxy.

    Science.gov (United States)

    Nogueira-de-Almeida, Carlos Alberto; de Almeida, Carla Cristina J N; Pereira, Natália Inocêncio; de Souza Filho, Nilton Antonio; de Oliveira, Valmir Aparecido

    2017-04-17

    To describe a case of an obese child whose weight gain was related to the Munchausen Syndrome by proxy (MSP). This is a case report including information regarding the child's clinical history and the mother's behavior. The common features of the syndrome are confronted with the description of the case, seeking to demonstrate the similarities. The description ratifies the diagnosis based on the signs and symptoms presented by the child (<5 years old, frequent contacts with health system, symptoms witnessed only by the mother, confusing findings, not helped by treatments, emotionally distant father) and the attitude of the mother (concerned, interested in procedures, comfortable in the medical setting, higher medical knowledge, hostile when thwarted). The case presented points to a new etiology, the MSP, to be considered within the set of factors currently known to cause and maintain obesity in childhood.

  15. Interactive images: Cuboid proxies for smart image manipulation

    KAUST Repository

    Zheng, Youyi

    2012-07-01

    Images are static and lack important depth information about the underlying 3D scenes. We introduce interactive images in the context of man-made environments wherein objects are simple and regular, share various non-local relations (e.g., coplanarity, parallelism, etc.), and are often repeated. Our interactive framework creates partial scene reconstructions based on cuboid-proxies with minimal user interaction. It subsequently allows a range of intuitive image edits mimicking real-world behavior, which are otherwise difficult to achieve. Effectively, the user simply provides high-level semantic hints, while our system ensures plausible operations by conforming to the extracted non-local relations. We demonstrate our system on a range of real-world images and validate the plausibility of the results using a user study. © 2012 ACM 0730-0301/2012/08-ART99.

  16. Reliability of proxy reports of parental smoking by elementary schoolchildren.

    Science.gov (United States)

    Barnett, T; O'Loughlin, J; Paradis, G; Renaud, L

    1997-08-01

    To investigate the reliability of reports of parental smoking by elementary schoolchildren aged 9-13 years, and to identify the correlates of disagreement between student proxy and parent self-reports. As part of the evaluation of a school-based heart health promotion program, data on parental smoking status were collected from 1240 student-mother pairs and 898 student-father pairs. Agreement for parental smoking status was 93.1% among student-mother pairs and 86.4% among student-father pairs. Among student-mother pairs, reports by students aged 9 years were more likely to disagree with mothers' self-reports than those of older children (odds ratio (OR) = 3.1). Among student-father pairs, the only significant correlate of disagreement was living in a single-parent family headed by the mother (OR = 2.6). Children 10-years or older can provide reliable reports of the smoking status of cohabiting parents.

  17. STRONTIUM DISTRIBUTION IN UPPER DEVONIAN CONODONT ELEMENTS: A PALAEOBIOLOGICAL PROXY

    Directory of Open Access Journals (Sweden)

    ANDREY V. ZHURAVLEV

    2017-04-01

    Full Text Available Conodonts are an extinct group of marine animals possessing debated affinities. The conodont elements are composed of calcium phosphate [apatite (CaF] and collagen-like proteins. Distribution of Sr in the bioapatite of albid, lamellar and paralamellar tissues of some Upper Devonian conodont element crowns from NW Russia was studied by microprobe. The calcium phosphate of the lamellar and paralamellar tissues demonstrates periodical oscillation of Sr contents across the lamellae (0.4-0.5 wt% in the outer part of lamella, and 0.2 wt% in the inner part. The albid tissue contains Sr of less than 0.4 wt%. It is suggested that oscillations of Sr concentrations reflect the periodic growth of the lamellae, and the average Ca/Sr ratio can be a proxy of the growth rate.

  18. Detecting the relationship between moisture changes in arid central Asia and East Asia during the Holocene by model-proxy comparison

    Science.gov (United States)

    Zhang, Xiaojian; Jin, Liya; Chen, Jie; Chen, Fahu; Park, Wonsun; Schneider, Birgit; Latif, Mojib

    2017-11-01

    Identifying the relationships between moisture changes in arid central Asia and those in East Asia may help us understand the interplay between the westerlies and the Asian summer monsoon. We combined proxy moisture records with the results from a transient simulation forced by changes in orbital parameters to analyse their relationships during the Holocene (9.5-0 ka BP). The proxy records and simulation results generally agree with a relatively dry early Holocene, the wettest period in the middle Holocene, and a dry late Holocene in East Asia. These periods were not solely controlled by precession-driven East Asian summer monsoon variability, but were significantly influenced by precipitation during the other seasons and by evaporation. However, different proxy records show contrasting results for moisture changes in arid central Asia during the Holocene. To study this, we analysed the climatic signals of the competing proxy records by comparing these proxy records with simulation results. We found that speleothem δ18O was significantly influenced by water vapour sources and evaporation rather than by the amount of precipitation. Thus, the model data reveals a persistent wetting trend throughout the Holocene that was out-of-phase with the trend in East Asia. The wetting trend in arid central Asia was caused by precipitation that increased faster than evaporation during the Holocene. The enhanced water vapour input from South Asia and the Middle East was the main cause of the increase in precipitation in arid central Asia, which in turn gave rise to the intensification of evaporation.

  19. One thousand years of fires: Integrating proxy and model data

    Directory of Open Access Journals (Sweden)

    Natalie Marie Kehrwald

    2016-04-01

    Full Text Available The current fires raging across Indonesia are emitting more carbon than the annual fossil fuel emissions of Germany or Japan, and the fires are still consuming vast tracts of rainforest and peatlands. The National Interagency Fire Center (www.nifc.gov notes that 2015 is one worst fire years on record in the U.S., where more than 9 million acres burned -- equivalent to the combined size of Massachusetts and New Jersey. The U.S. and Indonesian fires have already displaced tens of thousands of people, and their impacts on ecosystems are still unclear. In the case of Indonesia, the burning peat is destroying much of the existing soil, with unknown implications for the type of vegetation regrowth. Such large fires result from a combination of fire management practices, increasing anthropogenic land use, and a changing climate. The expected increase in fire activity in the upcoming decades has led to a surge in research trying to understand their causes, the factors that may have influenced similar times of fire activity in the past, and the implications of such fire activity in the future. Multiple types of complementary data provide information on the impacts of current fires and the extent of past fires. The wide array of data encompasses different spatial and temporal resolutions (Figure 1 and includes fire proxy information such as charcoal and tree ring fire scars, observational records, satellite products, modern emissions data, fire models within global land cover and vegetation models, and sociodemographic data for modeling past human land use and ignition frequency. Any single data type is more powerful when combined with another source of information. Merging model and proxy data enables analyses of how fire activity modifies vegetation distribution, air and water quality, and proximity to cities; these analyses in turn support land management decisions relating to conservation and development.

  20. Intensity modulated neutron radiotherapy optimization by photon proxy.

    Science.gov (United States)

    Snyder, Michael; Hammoud, Ahmad; Bossenberger, Todd; Spink, Robyn; Burmeister, Jay

    2012-08-01

    Introducing intensity modulation into neutron radiotherapy (IMNRT) planning has the potential to mitigate some normal tissue complications seen in past neutron trials. While the hardware to deliver IMNRT plans has been in use for several years, until recently the IMNRT planning process has been cumbersome and of lower fidelity than conventional photon plans. Our in-house planning system used to calculate neutron therapy plans allows beam weight optimization of forward planned segments, but does not provide inverse optimization capabilities. Commercial treatment planning systems provide inverse optimization capabilities, but currently cannot model our neutron beam. We have developed a methodology and software suite to make use of the robust optimization in our commercial planning system while still using our in-house planning system to calculate final neutron dose distributions. Optimized multileaf collimator (MLC) leaf positions for segments designed in the commercial system using a 4 MV photon proxy beam are translated into static neutron ports that can be represented within our in-house treatment planning system. The true neutron dose distribution is calculated in the in-house system and then exported back through the MATLAB software into the commercial treatment planning system for evaluation. The planning process produces optimized IMNRT plans that reduce dose to normal tissue structures as compared to 3D conformal plans using static MLC apertures. The process involves standard planning techniques using a commercially available treatment planning system, and is not significantly more complex than conventional IMRT planning. Using a photon proxy in a commercial optimization algorithm produces IMNRT plans that are more conformal than those previously designed at our center and take much less time to create. The planning process presented here allows for the optimization of IMNRT plans by a commercial treatment planning optimization algorithm, potentially allowing

  1. Sources and proxy potential of long chain alkyl diols in lacustrine environments

    Science.gov (United States)

    Rampen, Sebastiaan W.; Datema, Mariska; Rodrigo-Gámiz, Marta; Schouten, Stefan; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.

    2014-11-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD) composition of cultures of ten eustigmatophyte species, with three species from different families grown at various temperatures, to identify the effect of species composition and growth temperature on the LCD distribution. The results were compared with the LCD distribution of sixty-two lake surface sediments, and with previously reported LCD distributions from marine environments. The different families within the Eustigmatophyceae show distinct LCD patterns, with the freshwater family Eustigmataceae most closely resembling LCD distributions in both marine and lake environments. Unlike the other two eustigmatophyte families analyzed (Monodopsidaceae and Goniochloridaceae), C28 and C30 1,13-alkyl diols and C30 and C32 1,15-alkyl diols are all relatively abundant in the family Eustigmataceae, while the mono-unsaturated C32 1,15-alkyl diol was below detection limit. In contrast to the marine environment, LCD distributions in lakes did not show a clear relationship with temperature. The Long chain Diol Index (LDI), a proxy previously proposed for sea surface temperature reconstruction, showed a relatively weak correlation (R2 = 0.33) with mean annual air temperature used as an approximation for annual mean surface temperature of the lakes. A much-improved correlation (R2 = 0.74, p-value lipid distributions. The obtained regression model provides good estimates of temperatures for cultures of the family Eustigmataceae, suggesting that algae belonging to this family have an important role as a source for LCDs in lacustrine environments, or, alternatively, that the main sources of LCDs are similarly affected by temperature as the Eustigmataceae. The results suggest that LCDs may have

  2. Analisis Perbandingan Respons Time Squid Proxy Pada Windows Server dan Linux Server

    OpenAIRE

    Sirait, Parulian

    2016-01-01

    In the development of information technology, information is obtained quickly through technology computer network known as the Internet. The use bandwidth for Internet access can be maximized by using a proxy server. One of the proxy server is squid. The use squid as the proxy server need to consider the operating system on the server and have not known its best performance on any operating system yet. For that it is necessary to analyze the performance of squid proxy server on a different op...

  3. Development and Applications of Thallium isotopes: a new proxy tracking the extent of manganese oxide burial

    Science.gov (United States)

    Owens, J. D.; Nielsen, S.; Ostrander, C.; Peterson, L. C.; Anbar, A. D.

    2015-12-01

    Thallium (Tl) isotopes are a new and potential powerful paleoredox proxy with the possibility to track bottom water oxygen conditions based on the burial flux of manganese oxides. Thallium has a residence time of ~20 thousand years, which is long enough to render modern oxic seawater conservative with respect to concentration and isotopes. The isotopic signature of Tl in the global ocean is driven mainly by two outputs (1) adsorption onto manganese oxides and (2) low temperature oceanic crust alteration. Importantly, the isotopic inputs of Tl are all nearly the same value; thus, the isotopic composition and flux of the outputs almost exclusively set the seawater signature. For relatively short term redox events it is reasonable to assume that the dominant isotope fractionation process is associated with manganese oxide precipitation because low temperature alteration is controlled by long-term average ocean crust production rates. We present a broad range of modern samples that span several open ocean profiles combined with water column and sediment profiles from the permanently anoxic basins of the Black Sea and Cariaco Basins. The open ocean shows no variation in depth profiles that encompass most of the major water masses in the Atlantic and Southern Oceans. The anoxic basins, however, reveal Tl isotope signatures closer to their inputs, which is likely due to basinal restriction. The authigenic fraction of organic-rich sediments from the Black Sea and Cariaco Basin capture the Tl isotope value of the overlying water column, which shows that Tl isotopes could be applied as a faithful deep time redox proxy. For the first time, we will present new data showing that Tl isotopes is tracking bottom water ocean oxygenation. We are applying this isotope system to ancient samples, testing the spatial and temporal variability of ocean oxygenation coinciding with major biogeochemical events.

  4. Do proxies reflect patients' health concerns about urinary incontinence and gait problems?

    Science.gov (United States)

    Higashi, Takahiro; Hays, Ron D; Brown, Julie A; Kamberg, Caren J; Pham, Chau; Reuben, David B; Shekelle, Paul G; Solomon, David H; Young, Roy T; Roth, Carol P; Chang, John T; MacLean, Catherine H; Wenger, Neil S

    2005-01-01

    Background While falls and urinary incontinence are prevalent among older patients, who sometimes rely on proxies to provide their health information, the validity of proxy reports of concern about falls and urinary incontinence remains unknown. Methods Telephone interviews with 43 consecutive patients with falls or fear of falling and/or bothersome urinary incontinence and their proxies chosen by patients as most knowledgeable about their health. The questionnaire included items derived from the Medical Outcomes Study Short Form 12 (SF-12), a scale assessing concerns about urinary incontinence (UI), and a measure of fear of falling, the Falls Efficacy Scale (FES). Scores were estimated using items asking the proxy perspective (6 items from the SF-12, 10 items from a UI scale, and all 10 FES items). Proxy and patient scores were compared using intraclass correlation coefficients (ICC, one-way model). Variables associated with absolute agreement between patients and proxies were explored. Results Patients had a mean age of 81 years (range 75–93) and 67% were female while proxies had a mean age of 70 (range 42–87) and 49% were female. ICCs were 0.63 for the SF-12, 0.52 for the UI scale, and 0.29 for the FES. Proxies tended to understate patients' general health and incontinence concern, but overstate patients' concern about falling. Proxies who lived with patients and those who more often see patients more closely reflected patient FES scores compared to those who lived apart or those who saw patients less often. Internal consistency reliability of proxy responses was 0.62 for the SF-12, 0.86 for the I-QOL, and 0.93 for the FES. In addition, construct validity of the proxy FES scale was supported by greater proxy-perceived fear of falling for patients who received medical care after a fall during the past 12 months (p < .05). Conclusion Caution should be exercised when using proxies as a source of information about older patients' health perceptions. Questions

  5. Do proxies reflect patients' health concerns about urinary incontinence and gait problems?

    Directory of Open Access Journals (Sweden)

    Solomon David H

    2005-11-01

    Full Text Available Abstract Background While falls and urinary incontinence are prevalent among older patients, who sometimes rely on proxies to provide their health information, the validity of proxy reports of concern about falls and urinary incontinence remains unknown. Methods Telephone interviews with 43 consecutive patients with falls or fear of falling and/or bothersome urinary incontinence and their proxies chosen by patients as most knowledgeable about their health. The questionnaire included items derived from the Medical Outcomes Study Short Form 12 (SF-12, a scale assessing concerns about urinary incontinence (UI, and a measure of fear of falling, the Falls Efficacy Scale (FES. Scores were estimated using items asking the proxy perspective (6 items from the SF-12, 10 items from a UI scale, and all 10 FES items. Proxy and patient scores were compared using intraclass correlation coefficients (ICC, one-way model. Variables associated with absolute agreement between patients and proxies were explored. Results Patients had a mean age of 81 years (range 75–93 and 67% were female while proxies had a mean age of 70 (range 42–87 and 49% were female. ICCs were 0.63 for the SF-12, 0.52 for the UI scale, and 0.29 for the FES. Proxies tended to understate patients' general health and incontinence concern, but overstate patients' concern about falling. Proxies who lived with patients and those who more often see patients more closely reflected patient FES scores compared to those who lived apart or those who saw patients less often. Internal consistency reliability of proxy responses was 0.62 for the SF-12, 0.86 for the I-QOL, and 0.93 for the FES. In addition, construct validity of the proxy FES scale was supported by greater proxy-perceived fear of falling for patients who received medical care after a fall during the past 12 months (p Conclusion Caution should be exercised when using proxies as a source of information about older patients' health perceptions

  6. Stability Proxies for Water-in-Oil Emulsions and Implications in Aqueous-based Enhanced Oil Recovery

    Directory of Open Access Journals (Sweden)

    Mehrnoosh Moradi

    2011-07-01

    Full Text Available Several researchers have proposed that mobility control mechanisms can positively contribute to oil recovery in the case of emulsions generated in Enhanced-Oil Recovery (EOR operations. Chemical EOR techniques that use alkaline components or/and surfactants are known to produce undesirable emulsions that create operational problems and are difficult to break. Other water-based methods have been less studied in this sense. EOR processes such as polymer flooding and LoSalTM injection require adjustments of water chemistry, mainly by lowering the ionic strength of the solution or by decreasing hardness. The decreased ionic strength of EOR solutions can give rise to more stable water-in-oil emulsions, which are speculated to improve mobility ratio between the injectant and the displaced oil. The first step toward understanding the connection between the emulsions and EOR mechanisms is to show that EOR conditions, such as salinity and hardness requirements, among others, are conducive to stabilizing emulsions. In order to do this, adequate stability proxies are required. This paper reviews commonly used emulsion stability proxies and explains the advantages and disadvantage of methods reviewed. This paper also reviews aqueous-based EOR processes with focus on heavy oil to contextualize in-situ emulsion stabilization conditions. This context sets the basis for comparison of emulsion stability proxies.

  7. Design and Evaluation of a Proxy-Based Monitoring System for OpenFlow Networks.

    Science.gov (United States)

    Taniguchi, Yoshiaki; Tsutsumi, Hiroaki; Iguchi, Nobukazu; Watanabe, Kenzi

    2016-01-01

    Software-Defined Networking (SDN) has attracted attention along with the popularization of cloud environment and server virtualization. In SDN, the control plane and the data plane are decoupled so that the logical topology and routing control can be configured dynamically depending on network conditions. To obtain network conditions precisely, a network monitoring mechanism is necessary. In this paper, we focus on OpenFlow which is a core technology to realize SDN. We propose, design, implement, and evaluate a network monitoring system for OpenFlow networks. Our proposed system acts as a proxy between an OpenFlow controller and OpenFlow switches. Through experimental evaluations, we confirm that our proposed system can capture packets and monitor traffic information depending on administrator's configuration. In addition, we show that our proposed system does not influence significant performance degradation to overall network performance.

  8. Security analysis and enhanced user authentication in proxy mobile IPv6 networks.

    Directory of Open Access Journals (Sweden)

    Dongwoo Kang

    Full Text Available The Proxy Mobile IPv6 (PMIPv6 is a network-based mobility management protocol that allows a Mobile Node(MN connected to the PMIPv6 domain to move from one network to another without changing the assigned IPv6 address. The user authentication procedure in this protocol is not standardized, but many smartcard based authentication schemes have been proposed. Recently, Alizadeh et al. proposed an authentication scheme for the PMIPv6. However, it could allow an attacker to derive an encryption key that must be securely shared between MN and the Mobile Access Gate(MAG. As a result, outsider adversary can derive MN's identity, password and session key. In this paper, we analyze Alizadeh et al.'s scheme regarding security and propose an enhanced authentication scheme that uses a dynamic identity to satisfy anonymity. Furthermore, we use BAN logic to show that our scheme can successfully generate and communicate with the inter-entity session key.

  9. Design and Evaluation of a Proxy-Based Monitoring System for OpenFlow Networks

    Directory of Open Access Journals (Sweden)

    Yoshiaki Taniguchi

    2016-01-01

    Full Text Available Software-Defined Networking (SDN has attracted attention along with the popularization of cloud environment and server virtualization. In SDN, the control plane and the data plane are decoupled so that the logical topology and routing control can be configured dynamically depending on network conditions. To obtain network conditions precisely, a network monitoring mechanism is necessary. In this paper, we focus on OpenFlow which is a core technology to realize SDN. We propose, design, implement, and evaluate a network monitoring system for OpenFlow networks. Our proposed system acts as a proxy between an OpenFlow controller and OpenFlow switches. Through experimental evaluations, we confirm that our proposed system can capture packets and monitor traffic information depending on administrator’s configuration. In addition, we show that our proposed system does not influence significant performance degradation to overall network performance.

  10. Security analysis and enhanced user authentication in proxy mobile IPv6 networks.

    Science.gov (United States)

    Kang, Dongwoo; Jung, Jaewook; Lee, Donghoon; Kim, Hyoungshick; Won, Dongho

    2017-01-01

    The Proxy Mobile IPv6 (PMIPv6) is a network-based mobility management protocol that allows a Mobile Node(MN) connected to the PMIPv6 domain to move from one network to another without changing the assigned IPv6 address. The user authentication procedure in this protocol is not standardized, but many smartcard based authentication schemes have been proposed. Recently, Alizadeh et al. proposed an authentication scheme for the PMIPv6. However, it could allow an attacker to derive an encryption key that must be securely shared between MN and the Mobile Access Gate(MAG). As a result, outsider adversary can derive MN's identity, password and session key. In this paper, we analyze Alizadeh et al.'s scheme regarding security and propose an enhanced authentication scheme that uses a dynamic identity to satisfy anonymity. Furthermore, we use BAN logic to show that our scheme can successfully generate and communicate with the inter-entity session key.

  11. Appraising timing response of paleoenvironmental proxies to the Bond cycle in the western Mediterranean over the last 20 kyr

    Science.gov (United States)

    Rodrigo-Gámiz, Marta; Martínez-Ruiz, Francisca; Rodríguez-Tovar, Francisco J.; Pardo-Igúzquiza, Eulogio; Ortega-Huertas, Miguel

    2017-07-01

    The timing of climate responses to the Bond cycle is investigated in the western Mediterranean. Periodicities had been previously reported in a marine sediment record from this region spanning the last 20 kyr, and registered by diverse paleoenvironmental proxies, in particular those associated with terrigenous input, redox conditions, productivity, sea surface temperature (SST) and salinity. Further cross-spectral analyses on these time series reveal leads-lags in the 1400 year climate cycle. Considering as reference a terrigenous input proxy (the K/Al ratio), all the paleoenvironmental proxies displayed time shifts varying from ca. 700 year to ca. 350 year. SST and salinity variations show a first leaded response with the inflow of cold and less salty Atlantic waters. Followed by a time lead of 525 year, progresively arid conditions with an increase of eolian dust transport to the area, given by the Zr/Al signal, are observed. The intensification of dust transport could have triggered a latest biological response, lead by 350 year, with an increase of productivity, as suggested by the Ba/Al ratio. Lastly changes in the Mediterranean thermohaline circulation, indicated by a selected redox proxy (the U/Th ratio), are observed. These results support that the oceanic response triggered the atmospheric response to the Bond cycle in the western Mediterranean. Changes in the North Atlantic Oscillation mode and in the Inter-Tropical Convergence Zone migrations with variations in the monsoon activity or Saharan winds system, are considered as main forcing mechanisms, with a complex relationship of the involved phenomena.

  12. [Münchausen syndrome by proxy in a forensic psychiatric evaluation--the description of a case and ethical controversy].

    Science.gov (United States)

    Heitzman, Janusz; Opio, Małgorzata; Ruzikowska, Alfreda; Pilszyk, Anna

    2012-01-01

    Presentation of the difficulties in diagnosing Münchausen syndrome by proxy. Comparison of four different conclusions in forensic psychiatric opinions issued in one case, due to the need of answering to the questions of the court, in what periods and why was the deterioration of the child's health, in connection with an allegation that the mother has acted to his detriment. In the first medical-legal opinion the treating physician, while being the head of the ward and the person informing the police of the action against a child by the mother, recognised Münchausen syndrome by proxy. The second opinion was delivered by a psychologist, who stated that the mother distinguished the introspective attitude characterised by excessive, exaggerated accuracy, thoroughness, and did not give a unambiguous answer to the questions of the court. In the third opinion the experts accepted that the functioning of the subject does not create a threat to life and health of the child. The fourth opinion developed by the authors of this paper noted that in the analysed medical records of the childs' hospitalisation, no arguments were found to recognise Münchausen syndrome by proxy. RESULTS. In the conducted extended ambulant study of the subject and the analysis of the medical documentation of the 31 hospitalisations of the child showed that the improvement of the child's health was not associated in exclusion of pushing aside the mother from the child, but was the result of the consistency of the therapeutic treatment team, the continuation and the modification of the treatment. In appointing the expert, the art. 196 of the Code of Criminal Procedure should be considered, which states that the expert should not be the treating doctor, because his opinion loses value impartiality. Diagnosis of Münchausen Syndrome by proxy itself stirs up numerous controversies..

  13. A mid-Holocene thermal maximum at the end of the African Humid Period

    NARCIS (Netherlands)

    Berke, M.A.; Johnson, T.C.; Werne, J.P.; Schouten, S.; Sinninghe Damsté, J.S.

    2012-01-01

    The termination of the African Humid Period (AHP) about 5 thousand years ago (ka) was the most dramatic climate shift in northern and equatorial Africa since the end of the Pleistocene. Based on TEX86 paleotemperature data from lake Turkana, Kenya, we show that a temperature shift of 2-4 degrees C

  14. Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies

    Science.gov (United States)

    Jonkers, Lukas; Kučera, Michal

    2017-06-01

    The composition of planktonic foraminiferal (PF) calcite is routinely used to reconstruct climate variability. However, PF ecology leaves a large imprint on the proxy signal: seasonal and vertical habitats of PF species vary spatially, causing variable offsets from annual mean surface conditions recorded by sedimentary assemblages. PF seasonality changes with temperature in a way that minimises the environmental change that individual species experience and it is not unlikely that changes in depth habitat also result from such habitat tracking. While this behaviour could lead to an underestimation of spatial or temporal trends as well as of variability in proxy records, most palaeoceanographic studies are (implicitly) based on the assumption of a constant habitat. Up to now, the effect of habitat tracking on foraminifera proxy records has not yet been formally quantified on a global scale. Here we attempt to characterise this effect on the amplitude of environmental change recorded in sedimentary PF using core top δ18O data from six species. We find that the offset from mean annual near-surface δ18O values varies with temperature, with PF δ18O indicating warmer than mean conditions in colder waters (on average by -0.1 ‰ (equivalent to 0.4 °C) per °C), thus providing a first-order quantification of the degree of underestimation due to habitat tracking. We use an empirical model to estimate the contribution of seasonality to the observed difference between PF and annual mean δ18O and use the residual Δδ18O to assess trends in calcification depth. Our analysis indicates that given an observation-based model parametrisation calcification depth increases with temperature in all species and sensitivity analysis suggests that a temperature-related seasonal habitat adjustment is essential to explain the observed isotope signal. Habitat tracking can thus lead to a significant reduction in the amplitude of recorded environmental change. However, we show that this

  15. 75 FR 9073 - Amendments to Rules Requiring Internet Availability of Proxy Materials

    Science.gov (United States)

    2010-02-26

    ... an Internet Web site; it is not intended to serve as a stand-alone basis for making a voting decision... Exchange Commission 17 CFR Parts 230 and 240 Amendments to Rules Requiring Internet Availability of Proxy... Rules Requiring Internet Availability of Proxy Materials AGENCY: Securities and Exchange Commission...

  16. Improving age-depth models using sedimentary proxies for accumulation rates in fluvio-lacustrine deposits

    NARCIS (Netherlands)

    Minderhoud, P.S.J.; Cohen, K.M.|info:eu-repo/dai/nl/185633374; Toonen, W.H.J.|info:eu-repo/dai/nl/317725505; Erkens, G.|info:eu-repo/dai/nl/323349382; Hoek, W.Z.|info:eu-repo/dai/nl/163819394

    2017-01-01

    Lacustrine fills, including those of oxbow lakes in river floodplains, often hold valuable sedimentary and biological proxy records of palaeo-environmental change. Precise dating of accumulated sediments at levels throughout these records is crucial for interpretation and correlation of (proxy) data

  17. 47 CFR 51.513 - Proxies for forward-looking economic cost.

    Science.gov (United States)

    2010-10-01

    ... SERVICES (CONTINUED) INTERCONNECTION Pricing of Elements § 51.513 Proxies for forward-looking economic cost... a cost study that complies with the forward-looking economic cost based pricing methodology... rates that apply in separate geographic areas in a state. (c) Proxies for specific elements—(1) Local...

  18. Diagnostic, Explanatory, and Detection Models of Munchausen by Proxy: Extrapolations from Malingering and Deception

    Science.gov (United States)

    Rogers, Richard

    2004-01-01

    Objective: The overriding objective is a critical examination of Munchausen syndrome by proxy (MSBP) and its closely-related alternative, factitious disorder by proxy (FDBP). Beyond issues of diagnostic validity, assessment methods and potential detection strategies are explored. Methods: A painstaking analysis was conducted of the MSBP and FDBP…

  19. Anxiety and worry when coping with cancer treatment: agreement between patient and proxy responses.

    Science.gov (United States)

    Hermont, Ana Paula; Scarpelli, Ana Carolina; Paiva, Saul M; Auad, Sheyla M; Pordeus, Isabela A

    2015-06-01

    Assess agreement between proxy respondents (caregivers) and children/adolescents related to the impact of cancer on children's/adolescents' health-related quality of life, with respect to anxiety and worry issues. A cross-sectional study was conducted among 83 Brazilian children/adolescents, of both genders, diagnosed with cancer, aged 5-18 years and their proxy respondents. Anxiety and worry were assessed through items of the instrument Pediatric Quality of Life Inventory™ Cancer Module Scale. Participants were recruited from the pediatric hematology/oncology centers at two public hospitals. All individuals were receiving medical care. Descriptive statistics were performed as well as a weighted kappa coefficient, Spearman's correlation coefficient, Wilcoxon signed-rank test and Bland-Altman plots. The magnitude of the difference between the mean scores obtained from children/adolescents and that of their proxy respondents was evaluated through effect size. The proxy respondents underestimated the feelings of worry among children (8-12 years) (p anxiety (p children/adolescents to report increasing feelings of worry as they got older. In the 'treatment anxiety' subscale, there was a tendency for proxy respondents to present higher mean scores, revealing that proxy respondents believed the children's/adolescents' treatment anxiety decreased as they aged. Discrepancies between the reports of children/adolescents and their proxy respondents were observed. Children's/adolescents' reports should not be ignored nor replaced by proxy reports; both reports should be analyzed together.

  20. Patient-rated versus proxy-rated cognitive and functional measures in older adults

    Directory of Open Access Journals (Sweden)

    Howland M

    2017-03-01

    Full Text Available Molly Howland,1 Kevin C Allan,1 Caitlin E Carlton,1 Curtis Tatsuoka,2–4 Kathleen A Smyth,3 Martha Sajatovic1,2,4,5 1Case Western Reserve University School of Medicine, 2Neurological and Behavioral Outcomes Center, University Hospitals Case Medical Center, 3Department of Epidemiology and Biostatistics, 4Department of Neurology, 5Department of Psychiatry, Case Western Reserve University School of Medicine, Cleveland, OH, USA Objectives: Patients with cognitive impairment may have difficulty reporting their functional and cognitive abilities, which are important clinical outcomes. Health care proxies may be able to corroborate patient self-reports. Several studies reported discrepancy between patient and proxy ratings, though the literature is sparse on changes over time of these ratings. Our goals in this 12-month study were to compare patient and proxy reports on functioning, cognition, and everyday executive function, and to further elucidate correlates of patient–proxy discrepancy. Methods: This was a prospective cohort study of individuals older than 70 years who ranged from having no cognitive impairment to having moderate dementia who had a proxy available to complete instruments at baseline (N=76. Measurements included Alzheimer’s Disease Cooperative Study–Activities of Daily Living Inventory (ADCS-ADLI, Neuro-QOL Executive Function, PROMIS Applied Cognition (PROMIS-Cog, Mini-Mental State Examination (MMSE, and Geriatric Depression Scale. Results: Patient- and proxy-rated ADCS-ADLI were correlated at baseline and at 1-year follow-up. Patient and proxy ratings were discrepant on Neuro-QOL Executive Function and PROMIS-Cog. Greater patient–proxy discrepancy on PROMIS-Cog was associated with younger age and less depression, and greater patient–proxy discrepancy on Neuro-QOL Executive Function was associated with less depression and worse cognitive impairment. Patient–proxy discrepancy increased over time for everyday executive

  1. Constraining trace metal paleo-proxies for black shale deposition in upwelling systems: the Benguela upwelling system offshore Namibia

    Science.gov (United States)

    Cofrancesco, J.; Riedinger, N.; Owens, J. D.

    2016-12-01

    Geochemical trace metal paleo-proxies are powerful tools for reconstructing the depositional environment of black shales. However, not all relationships and environmental conditions have been well-studied as discrepancies remain between geochemical and sedimentological proxies. While there are numerous proxies for understanding endmember redox conditions there is still a significant gap in regards to constraining oxygen minimum zones (OMZ) in ancient settings, for instance Devonian epeiric sea black shale deposits. This study aims to explore the application of geochemical and sedimentological proxies on a modern marginal marine setting - the Benguela upwelling system, offshore Namibia. This region is a modern analogue to ancient black shale formation. In this upwelling system the lateral transport of the shelf mudbelt's organic-rich sediments, deposited under anoxic (sulfidic) bottom waters, are being re-deposited under the oxygen-rich water column of the upper slope, resulting in a secondary transported organic carbon depocenter. To assess the geochemical inventory of these two different areas of organic carbon preservation, we obtained a transect of sediment cores along the shelf and slope, via the R/V MIRABILIS as a part of the 2015 Regional Graduate Network in Oceanography (RGNO) program in Namibia. The core sites were strategically sited in areas of differing water depth and redox conditions to capture a range of trace metal enrichments and organic carbon inventory. Sediments were analyzed for major elements, iron phases, and grain-size distribution. Trace metals were analyzed in the bottom water, pore water, and surface sediments. Results showed a large enrichment variation for several redox sensitive trace metals. Overall, the trace metals follow the expected trend for redox proxies, with highest enrichment in the sediments below the anoxic bottom waters. Interestingly though, some redox sensitive metals show higher enrichment in the bioturbated, mildly

  2. Identification of climatic state with limited proxy data

    Directory of Open Access Journals (Sweden)

    J. D. Annan

    2012-07-01

    Full Text Available We investigate the identifiability of the climate by limited proxy data. We test a data assimilation approach through perfect model pseudoproxy experiments, using a simple likelihood-based weighting based on the particle filtering process. Our experimental set-up enables us to create a massive 10 000-member ensemble at modest computational cost, thus enabling us to generate statistically robust results. We find that the method works well when data are sparse and imprecise, but in this case the reconstruction has a rather low accuracy as indicated by residual RMS errors. Conversely, when data are relatively plentiful and accurate, the estimate tracks the target closely, at least when considering the hemispheric mean. However, in this case, our prior ensemble size of 10 000 appears to be inadequate to correctly represent the true posterior, and the regional performance is poor. Using correlations to assess performance gives a more encouraging picture, with significant correlations ranging from about 0.3 when data are sparse to values over 0.7 when data are plentiful, but the residual RMS errors are substantial in all cases. Our results imply that caution is required in interpreting climate reconstructions, especially when considering the regional scale, as skill on this basis is markedly lower than on the large scale of hemispheric mean temperature.

  3. Medieval horse stable; the results of multi proxy interdisciplinary research.

    Science.gov (United States)

    Dejmal, Miroslav; Lisá, Lenka; Fišáková Nývltová, Miriam; Bajer, Aleš; Petr, Libor; Kočár, Petr; Kočárová, Romana; Nejman, Ladislav; Rybníček, Michal; Sůvová, Zdenka; Culp, Randy; Vavrčík, Hanuš

    2014-01-01

    A multi proxy approach was applied in the reconstruction of the architecture of Medieval horse stable architecture, the maintenance practices associated with that structure as well as horse alimentation at the beginning of 13th century in Central Europe. Finally, an interpretation of the local vegetation structure along Morava River, Czech Republic is presented. The investigated stable experienced two construction phases. The infill was well preserved and its composition reflects maintenance practices. The uppermost part of the infill was composed of fresh stabling, which accumulated within a few months at the end of summer. Horses from different backgrounds were kept in the stable and this is reflected in the results of isotope analyses. Horses were fed meadow grasses as well as woody vegetation, millet, oat, and less commonly hemp, wheat and rye. Three possible explanations of stable usage are suggested. The stable was probably used on a temporary basis for horses of workers employed at the castle, courier horses and horses used in battle.

  4. Music Therapy by Proxy: Using Humanised Images in Song

    Directory of Open Access Journals (Sweden)

    Carol Chambers

    2013-07-01

    Full Text Available Developing awareness, exploration and expression of emotionally sensitive issues can be difficult for some clients in music therapy. They may find it hard to express emotion through improvised music and may turn instead to the perceived security of the repetition of known songs.This paper presents the results from a completed research PhD, a qualitative case study based on naturalistic clinical practice, which examined the song choices of one woman in a medium-secure forensic unit over the three-year course of her music therapy. A descriptive narrative account was subjected to analysis according to a modified form of therapeutic narrative analysis (Aldridge and Aldridge 2002, resulting in the abstraction of a series of generative metaphoric images, framed within a chronological series of events. Crucially, these images were found to be humanised figures, yet they were also emotionally decentred or depersonalised. When approached from the philosophical and methodological perspective of behaviourism, which views these as conditioned responses associating music with life experiences as part of a process of developing self-identity, such images can be seen to provide an unspoken voice for the client’s feelings to be expressed in a manner that is personally revealing, socially acceptable, culturally accessible and therapeutically constructive.I assert that using these third-person characters as a form of proxy facilitates mutual reference and experimentation, and places music firmly at the heart of a socially constructed process of music therapy.

  5. A Rare Reason of Hyperinsulinism: Munchausen Syndrome by Proxy.

    Science.gov (United States)

    Akın, Onur; Yeşilkaya, Ediz; Sari, Erkan; Akar, Çağdaş; Başbozkurt, Gökalp; Macit, Enis; Aydin, Ibrahim; Taşlipinar, Abdullah; Gül, Hüsamettin

    2016-01-01

    Hyperinsulinism, one of the most important causes of hypoglycaemia, can be congenital or acquired. Rarely, drug toxicity can be a reason for hyperinsulinism. In the context of Munchausen syndrome by proxy (MSP), toxicity usually occurs in children due to drug administration by a parent or caregiver. A 7-year-old girl was referred to our department due to a hyperglycaemic period and hypoglycaemic episodes. On admission, gliclazide was initiated due to her hyperglycaemia, which we attributed to maturity onset diabetes of the young. However, during follow-up, hypoglycaemic levels were detected. Despite cessation of gliclazide, hypoglycaemic seizures occurred. Even with the medications administered, hypoglycaemia could not be prevented. During follow-up, the mother's affect, characterized by anxiety and interest in her daughter's medical care, appeared discordant with the situation. Due to our suspicion of MSP, we discovered toxic levels of gliclazide in the blood and urine samples which had been sent to the toxicology laboratory to search for hypoglycaemic agents. The patient was isolated, and all medications were stopped. After isolation, her hypoglycaemia disappeared, and she became hyperglycaemic (250 mg/dl). Physicians should consider the possibility of MSP in hyperinsulinaemic patients with discordant laboratory results and clinical symptoms, even if the child's parents display great concern. © 2016 S. Karger AG, Basel.

  6. Severe hypernatremia in a hospitalized child: munchausen by proxy.

    Science.gov (United States)

    Su, Erik; Shoykhet, Michael; Bell, Michael J

    2010-10-01

    An 8-week-old infant presented to a referring institution with profuse diarrhea and infectious enteritis for 1 week. He was initially treated for suspected Salmonella spp. sepsis and meningitis, because the organism was found in the stool, but the child's illness progressed, manifested by paroxysmal profuse diarrhea and increased urine output. After several weeks, he suffered a sagittal venous thrombosis and intracranial hemorrhage. Subsequently the child was transferred to a tertiary center for intestinal evaluation. The patient's diarrhea and excessive diuresis resolved, and his sodium normalized soon after transfer. Four days later, however, after his mother arrived, he immediately developed severe hypernatremia (serum sodium concentration [Na(+)] = 214 mEq/L), with resumption of diarrhea and excessive diuresis. A gastric aspirate during the crisis demonstrated an extremely high sodium content, [Na(+)] = 1416 mEq/L, consistent with salt intoxication. Surveillance of the mother revealed that she manipulated the indwelling nasogastric tube; confronted, she admitted to salt administration. This case describes one of the ways that Munchausen syndrome by proxy can manifest with profound neurologic sequelae, and highlights the need for close observation and swift intervention when sufficient cause is present. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Cognitive-Behavioral Therapy for Body Dysmorphic Disorder by Proxy.

    Science.gov (United States)

    Greenberg, Jennifer L; Mothi, Suraj Sarvode; Wilhelm, Sabine

    2016-07-01

    Body dysmorphic disorder (BDD) is a distressing or impairing preoccupation with a perceived defect in physical appearance. BDD by proxy (BDDBP) is a significant but understudied variant of BDD in which the primary preoccupation involves perceived imperfections of another person. Like BDD, individuals with BDDBP engage in time-consuming rituals to "fix" the other person's appearance or alleviate distress. Avoidance is common and the impact of BDDBP on social functioning is profound. Cognitive-behavioral therapy (CBT) is the best-studied and most promising psychological treatment for BDD, but no studies have examined its generalizability to the BDDBP variant. We tested feasibility, acceptability, and treatment outcome of CBT modified for BDDBP in a sample of 6 adults with primary BDDBP. Treatment was delivered in weekly individual sessions over 12-20weeks. Mean symptom severity (BDDBP-YBOCS) dropped from the moderately severe range at pretreatment to the subclinical range at posttreatment, t(6)=10.7, p<.001, d=3.3. One hundred percent of treatment completers were responders (≥30% reduction in BDDBP-YBOCS). Insight also improved. Treatment gains were maintained at 3-month follow-up. To our knowledge, this represents the first treatment study for BDDBP. Copyright © 2016. Published by Elsevier Ltd.

  8. A brief intervention for preparing ICU families to be proxies: A phase I study.

    Science.gov (United States)

    Turnbull, Alison E; Chessare, Caroline M; Coffin, Rachel K; Needham, Dale M

    2017-01-01

    Family members of critically ill patients report high levels of conflict with clinicians, have poor understanding of prognosis, struggle to make decisions, and experience substantial symptoms of anxiety, depression, and post-traumatic stress regardless of patient survival status. Efficient interventions are needed to prepare these families to act as patient proxies. To assess a brief "patient activation" intervention designed to set expectations and prepare families of adult intensive care unit (ICU) patients to communicate effectively with the clinical team. Phase I study of acceptability and immediate side effects. 122 healthcare proxies of 111 consecutive patients with a stay of ≥24 hours in the Johns Hopkins Hospital Medical ICU (MICU), in Baltimore, Maryland. Reading aloud to proxies from a booklet (Flesch-Kincard reading grade level 3.8) designed with multidisciplinary input including from former MICU proxies. Enrolled proxies had a median age of 51 years old with 83 (68%) female, and 55 (45%) African-American. MICU mortality was 18%, and 37 patients (33%) died in hospital or were discharged to hospice. Among proxies 98% (95% CI: 94% - 100%) agreed or strongly agreed that the intervention was appropriate, 98% (95% CI: 92% - 99%) agreed or strongly agreed that it is important for families to know the information in the booklet, and 54 (44%, 95% CI 35%- 54%) agreed or strongly agreed that parts of the booklet are upsetting. Upset vs. non-upset proxies were not statistically or substantially different in terms of age, sex, education level, race, relation to the patient, or perceived decision-making authority. This patient activation intervention was acceptable and important to nearly all proxies. Frequently, the intervention was simultaneously rated as both acceptable/important and upsetting. Proxies who rated the intervention as upsetting were not identifiable based on readily available proxy or patient characteristics.

  9. A Multi-Component Proxy for OH Variability Measured from Space: Evaluation and Evolution

    Science.gov (United States)

    Murray, L. T.; Fiore, A. M.; Valin, L. C.

    2014-12-01

    Observed changes in the decay rate of methyl chloroform (MCF; CH3CCl3) have been the traditional top-down constraint for variability in tropospheric abundances of the hydroxyl radical (OH), and thereby the oxidative capacity of the atmosphere. However, as atmospheric MCF concentrations approach detection limits following its ban under the Montréal Protocol, it is necessary to identify new proxies for global OH and its variability. We present here a novel proxy for tropospheric OH using convolved observations of total and tropospheric columns of ozone, water vapor, NO2, and CO, available from the Aura and Aqua satellites in the NASA Earth Observing System constellation. Derived from photochemical steady-state assumptions, the satellite proxy generates spatiotemporally coherent monthly percent anomalies in column OH for Oct. 2004 through Sept. 2012. We demonstrate that the temporal evolution of the globally integrated signal is statistically consistent with changes inferred by the MCF decay rate during this period. The magnitude of interannual variability in the satellite OH proxy is smaller than that from MCF, more consistent with global chemical transport models (CTMs). We evaluate the proxy by comparing to 9-year hind-cast simulations of the GEOS-Chem global CTM driven by MERRA reanalysis meteorology at 2° x 2.5° horizontal resolution, and find that the satellite proxy correlates with the airmass-weighted tropospheric monthly mean OH anomalies (R = 0.6; n = 96 months). The satellite proxy and model simulations indicate regional-scale coherent OH anomalies for many regions and seasons; where discrepancies occur, we highlight possible causes. We present a source attribution of the spatial and temporal patterns in the satellite OH proxy, informed by the individual components of the satellite proxy, a series of zero-emission sensitivity simulations with GEOS-Chem, and independent proxies for major modes of climate variability.

  10. A brief intervention for preparing ICU families to be proxies: A phase I study.

    Directory of Open Access Journals (Sweden)

    Alison E Turnbull

    Full Text Available Family members of critically ill patients report high levels of conflict with clinicians, have poor understanding of prognosis, struggle to make decisions, and experience substantial symptoms of anxiety, depression, and post-traumatic stress regardless of patient survival status. Efficient interventions are needed to prepare these families to act as patient proxies.To assess a brief "patient activation" intervention designed to set expectations and prepare families of adult intensive care unit (ICU patients to communicate effectively with the clinical team.Phase I study of acceptability and immediate side effects.122 healthcare proxies of 111 consecutive patients with a stay of ≥24 hours in the Johns Hopkins Hospital Medical ICU (MICU, in Baltimore, Maryland.Reading aloud to proxies from a booklet (Flesch-Kincard reading grade level 3.8 designed with multidisciplinary input including from former MICU proxies.Enrolled proxies had a median age of 51 years old with 83 (68% female, and 55 (45% African-American. MICU mortality was 18%, and 37 patients (33% died in hospital or were discharged to hospice. Among proxies 98% (95% CI: 94% - 100% agreed or strongly agreed that the intervention was appropriate, 98% (95% CI: 92% - 99% agreed or strongly agreed that it is important for families to know the information in the booklet, and 54 (44%, 95% CI 35%- 54% agreed or strongly agreed that parts of the booklet are upsetting. Upset vs. non-upset proxies were not statistically or substantially different in terms of age, sex, education level, race, relation to the patient, or perceived decision-making authority.This patient activation intervention was acceptable and important to nearly all proxies. Frequently, the intervention was simultaneously rated as both acceptable/important and upsetting. Proxies who rated the intervention as upsetting were not identifiable based on readily available proxy or patient characteristics.

  11. Alimemazine poisoning as evidence of Munchausen syndrome by proxy: A pediatric case report.

    Science.gov (United States)

    Gomila, Isabel; López-Corominas, Victoria; Pellegrini, Manuela; Quesada, Loreto; Miravet, Elena; Pichini, Simona; Barceló, Bernardino

    2016-09-01

    Munchausen syndrome by proxy (MSBP), also known as fabricated or induced illness in a child by a caretaker, is a form of abuse where a caregiver deliberately produces or feigns illness in a person under his or her care, so that the proxy will receive medical care that gratifies the caregiver. The affected children are often hospitalized for long periods and endure repetitive, painful and expensive diagnostic attempts. We present an analytically confirmed case of MSBP by alimemazine. A 3-year-old boy was brought repetitively to a Pediatric Emergency Department by his mother because he presented limb tremors, dysarthria, obnubilation, and ataxia and generalized tonic-clonic seizures coinciding with intermittent fever. Neither the rest of the physical examination nor the complementary tests showed any significant alterations. MSBP was suspected and a routine systematic toxicological analysis in urine and blood was requested. Alimemazine was detected in all biological samples. The administration of this drug was never mentioned by the mother and the subsequent interview with her corroborated the suspicion of MSBP. Clinically, after separation from the mother, the child's neurological symptoms gradually improved until the complete disappearance of the cerebellar symptoms. Alimemazine was quantified in serum, urine, gastric content and cerebrospinal fluid samples by gas chromatography-mass spectrometry (maximum serum level was 0.42μg/ml). Hair quantification of alimemazine was performed by ultra-performance liquid chromatography-tandem mass spectrometry in different segments of hair. The results confirmed regular substance use during the at least eight last months (8.8, 14.7, 19.7 and 4.6ng/mg hair starting from most proximal segment). This patient represents the first case published with analytical data of alimemazine in blood, urine, gastric content, cerebrospinal fluid and hair, which allowed us to prove an acute and repetitive poisoning with alimemazine as evidence

  12. Are Quality-Adjusted Life Years a Good Proxy Measure of Individual Capabilities?

    Science.gov (United States)

    Mitchell, Paul Mark; Venkatapuram, Sridhar; Richardson, Jeff; Iezzi, Angelo; Coast, Joanna

    2017-06-01

    There is a debate in the health economics literature concerning the most appropriate way of applying Amartya Sen's capability approach in economic evaluation studies. Some suggest that quality-adjusted life years (QALYs) alone are adequate while others argue that this approach is too narrow and that direct measures of capability wellbeing provide a more extensive application of Sen's paradigm. This paper empirically explores whether QALYs provide a good proxy for individual capabilities. Data is taken from a multinational cross-sectional survey of individuals with seven health conditions (asthma, arthritis, cancer, depression, diabetes, hearing loss, heart disease) and a healthy population. Each individual completed the ICECAP-A measure of capability wellbeing for adults and six health utility instruments that are used to generate QALYs, including EQ-5D and SF-6D. Primary analysis examines how well health utility instruments can explain variation in the ICECAP-A using ordinary least squares regression. The findings show that all seven health conditions have a negative association on overall capability as measured by the ICECAP-A index. Inclusion of health utility instruments into separate regressions improves the predictive power of capability but on average, explains less than half of the variation in capability wellbeing. Individuals with arthritis appear to be less inhibited in terms of capability losses when accounting for health utility, yet those who have depression record significant reductions in capability relative to the healthy population even after accounting for the most commonly used health utility instruments. The study therefore casts doubt on the ability of QALYs to act as a reliable proxy measure of individuals' capability.

  13. Understanding north-western Mediterranean climate variability: a multi-proxy and multi-sequence approach based on wavelet analysis.

    Science.gov (United States)

    Azuara, Julien; Lebreton, Vincent; Jalali, Bassem; Sicre, Marie-Alexandrine; Sabatier, Pierre; Dezileau, Laurent; Peyron, Odile; Frigola, Jaime; Combourieu-Nebout, Nathalie

    2017-04-01

    Forcings and physical mechanisms underlying Holocene climate variability still remain poorly understood. Comparison of different paleoclimatic reconstructions using spectral analysis allows to investigate their common periodicities and helps to understand the causes of past climate changes. Wavelet analysis applied on several proxy time series from the Atlantic domain already revealed the first key-issues on the origin of Holocene climate variability. However the differences in duration, resolution and variance between the time-series are important issues for comparing paleoclimatic sequences in the frequency domain. This work compiles 7 paleoclimatic proxy records from 4 time-series from the north-western Mediterranean all ranging from 7000 to 1000 yrs cal BP: -pollen and clay mineral contents from the lagoonal sediment core PB06 recovered in southern France, -Sea Surface Temperatures (SST) derived from alkenones, concentration of terrestrial alkanes and their average chain length (ACL) from core KSGC-31_GolHo-1B recovered in the Gulf of Lion inner-shelf, - δ18O record from speleothems recovered in the Asiul Cave in north-western Spain, -grain size record from the deep basin sediment drift core MD99-2343 north of Minorca island. A comparison of their frequency content is proposed using wavelet analysis and cluster analysis of wavelet power spectra. Common cyclicities are assessed using cross-wavelet analysis. In addition, a new algorithm is used in order to propagate the age model errors within wavelet power spectra. Results are consistents with a non-stationnary Holocene climate variability. The Halstatt cycles (2000-2500 years) depicted in many proxies (ACL, errestrial alkanes and SSTs) demonstrate solar activity influence in the north-western Mediterranean climate. Cluster analysis shows that pollen and ACL proxies, both indicating changes in aridity, are clearly distinct from other proxies and share significant common periodicities around 1000 and 600 years

  14. Geochemical Proxies for Enhanced Process Control of Underground Coal Gasification

    Science.gov (United States)

    Kronimus, A.; Koenen, M.; David, P.; Veld, H.; van Dijk, A.; van Bergen, F.

    2009-04-01

    Underground coal gasification (UCG) represents a strategy targeting at syngas production for fuel or power generation from in-situ coal seams. It is a promising technique for exploiting coal deposits as an energy source at locations not allowing conventional mining under economic conditions. Although the underlying concept has already been suggested in 1868 and has been later on implemented in a number of field trials and even at a commercial scale, UCG is still facing technological barriers, impeding its widespread application. Field UCG operations rely on injection wells enabling the ignition of the target seam and the supply with oxidants (air, O2) inducing combustion (oxidative conditions). The combustion process delivers the enthalpy required for endothermic hydrogen production under reduction prone conditions in some distance to the injection point. The produced hydrogen - usually accompanied by organic and inorganic carbon species, e.g. CH4, CO, and CO2 - can then be retrieved through a production well. In contrast to gasification of mined coal in furnaces, it is difficult to measure the combustion temperature directly during UCG operations. It is already known that geochemical parameters such as the relative production gas composition as well as its stable isotope signature are related to the combustion temperature and, consequently, can be used as temperature proxies. However, so far the general applicability of such relations has not been proven. In order to get corresponding insights with respect to coals of significantly different rank and origin, four powdered coal samples covering maturities ranging from Ro= 0.43% (lignite) to Ro= 3.39% (anthracite) have been gasified in laboratory experiments. The combustion temperature has been varied between 350 and 900 ˚ C, respectively. During gasification, the generated gas has been captured in a cryo-trap, dried and the carbon containing gas components have been catalytically oxidized to CO2. Thereafter, the

  15. A Lattice-Based Identity-Based Proxy Blind Signature Scheme in the Standard Model

    Directory of Open Access Journals (Sweden)

    Lili Zhang

    2014-01-01

    Full Text Available A proxy blind signature scheme is a special form of blind signature which allowed a designated person called proxy signer to sign on behalf of original signers without knowing the content of the message. It combines the advantages of proxy signature and blind signature. Up to date, most proxy blind signature schemes rely on hard number theory problems, discrete logarithm, and bilinear pairings. Unfortunately, the above underlying number theory problems will be solvable in the postquantum era. Lattice-based cryptography is enjoying great interest these days, due to implementation simplicity and provable security reductions. Moreover, lattice-based cryptography is believed to be hard even for quantum computers. In this paper, we present a new identity-based proxy blind signature scheme from lattices without random oracles. The new scheme is proven to be strongly unforgeable under the standard hardness assumption of the short integer solution problem (SIS and the inhomogeneous small integer solution problem (ISIS. Furthermore, the secret key size and the signature length of our scheme are invariant and much shorter than those of the previous lattice-based proxy blind signature schemes. To the best of our knowledge, our construction is the first short lattice-based identity-based proxy blind signature scheme in the standard model.

  16. A Proxy Outcome Approach for Causal Effect in Observational Studies: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Wenbin Liang

    2014-01-01

    Full Text Available Background. Known and unknown/unmeasured risk factors are the main sources of confounding effects in observational studies and can lead to false observations of elevated protective or hazardous effects. In this study, we investigate an alternative approach of analysis that is operated on field-specific knowledge rather than pure statistical assumptions. Method. The proposed approach introduces a proxy outcome into the estimation system. A proxy outcome possesses the following characteristics: (i the exposure of interest is not a cause for the proxy outcome; (ii causes of the proxy outcome and the study outcome are subsets of a collection of correlated variables. Based on these two conditions, the confounding-effect-driven association between the exposure and proxy outcome can then be measured and used as a proxy estimate for the effects of unknown/unmeasured confounders on the outcome of interest. Performance of this approach is tested by a simulation study, whereby 500 different scenarios are generated, with the causal factors of a proxy outcome and a study outcome being partly overlapped under low-to-moderate correlations. Results. The simulation results demonstrate that the conventional approach only led to a correct conclusion in 21% of the 500 scenarios, as compared to 72.2% for the alternative approach. Conclusion. The proposed method can be applied in observational studies in social science and health research that evaluates the health impact of behaviour and mental health problems.

  17. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Science.gov (United States)

    Lüdecke, H.-J.; Hempelmann, A.; Weiss, C. O.

    2013-02-01

    The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detrended fluctuation analysis (DFA). For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar) and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  18. Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

    Directory of Open Access Journals (Sweden)

    H.-J. Lüdecke

    2013-02-01

    Full Text Available The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT, wavelets, and the detrended fluctuation analysis (DFA. For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

  19. Late Quaternary environmental change inferred from phytoliths and other soil-related proxies: Case studies from the central and southern Great Plains, USA

    Science.gov (United States)

    Cordova, C.E.; Johnson, W.C.; Mandel, R.D.; Palmer, M.W.

    2011-01-01

    This study investigates stable carbon isotopes (??13C), opal phytolith assemblages, burnt phytoliths, microscopic charcoal and Sporormiella spores from modern soils and paleosols in Kansas and Oklahoma. Grass and dicot phytoliths in combination with ??13C are used as proxies for reconstructing the structure of grasslands and woodlands. Burnt grass phytoliths and microscopic charcoal are evaluated as proxies for reconstructing paleofire incidence. Concentrations of the fungal spore Sporormiella are used as a proxy for assessing large herbivore activity. These proxies were tested on various modern grassland communities of the central and southern Great Plains, including areas with bison, cattle, and small herbivores, and areas under different fire frequencies.Opal phytolith assemblages and ??13C values show that before cal 11ka, C3 grasses and woody plants predominated in areas that today are dominated by C4 grasses. The origin of the shortgrass prairie dates back to about cal 10ka. The origin of the tallgrass prairie, however, is not clear as phytolith data show variable assemblages throughout the Holocene (mixed-grass, tallgrass, and tallgrass-woodland mosaic). Different proxies (burnt phytoliths vs. charcoal) reveal different fire frequencies, but it is apparent that microfossil evidence for fire incidence is closely related to the abundance of woody plants in the landscape.Before cal 12. ka, soils show somewhat elevated concentration of Sporormiella, but lower concentrations than the modern high-density bison and cattle grazing areas. Throughout the Holocene, Sporormiella frequencies are low, which suggests lower large ungulate densities and perhaps high mobility. ?? 2010 Elsevier B.V.

  20. An ethical analysis of proxy and waiver of consent in critical care research

    DEFF Research Database (Denmark)

    Berg, Ronan M G; Møller, Kirsten; Rossel, Peter J. Hancke

    2013-01-01

    a substituted judgement by a close relative or friend, based on knowledge of patient's values, preferences, and view of life. For the consent to be genuine, the proxy must be informed of and understand three fundamental aspects of research practice: (1) that participation is voluntary and the consent can......It is a central principle in medical ethics that vulnerable patients are entitled to a degree of protection that reflects their vulnerability. In critical care research, this protection is often established by means of so-called proxy consent. Proxy consent for research participation constitutes...

  1. High Resolution ITRAX Analysis of Les Echets (France) Sedimentary Sequence: Linking Geochemical, Biological and Physical Proxies

    Science.gov (United States)

    Wohlfarth, B.; Kylander, M. E.; Ampel, L.; Veres, D.

    2008-12-01

    We present a 30 m long, high-resolution, independently-dated multi-proxy lake sediment record from Les Echets in south-central France which covers the later part of Marine Isotope Stage (MIS) 3 and MIS 2 (40 and 16 ka BP). The sediments in the lower part of the studied sequence are composed of alternating organic rich and minerogenic layers, while the upper part consists predominantly of silt and clay. Organic geochemical, geophysical and biological environmental indicators (grain size, mineral magnetic parameters, TOC, TN, LOI, stable carbon isotopes, rock eval, biogenic silica, and diatom assemblages) show alternating phases of higher and low lake organic productivity which are interpreted as a response to DO climate variability. XRF is a well-established analytical tool that has recently taken a new direction with the introduction of core scanning systems. The ITRAX XRF core scanning system is non-destructive, acquires continuous data for a broad range of elements in situ as well as generates radiographic images. The Les Echets sequence was analysed using the ITRAX at 1 mm resolution. The radiographic images show significant changes that were not revealed by lithostratigraphic descriptions. Distinct, dense layers are associated with changes in elemental intensities which would have been missed using traditional sub-sampling techniques. The high resolution elemental profiles show associations between certain elements (Rb, Si, Ti and K; Sr and Ca) which can be linked to lake productivity and catchment erosion and by extension, paleoclimatic changes.

  2. The C32 alkane-1,15-diol as a proxy of late Quaternary riverine input in coastal margins

    Science.gov (United States)

    Lattaud, Julie; Dorhout, Denise; Schulz, Hartmut; Castañeda, Isla S.; Schefuß, Enno; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2017-08-01

    The study of past sedimentary records from coastal margins allows us to reconstruct variations in terrestrial input into the marine realm and to gain insight into continental climatic variability. There are numerous organic proxies for tracing terrestrial input into marine environments but none that strictly reflect the input of river-produced organic matter. Here, we test the fractional abundance of the C32 alkane 1,15-diol relative to all 1,13- and 1,15-long-chain diols (FC32 1, 15) as a tracer of input of river-produced organic matter in the marine realm in surface and Quaternary (0-45 ka) sediments on the shelf off the Zambezi and nearby smaller rivers in the Mozambique Channel (western Indian Ocean). A Quaternary (0-22 ka) sediment record off the Nile River mouth in the eastern Mediterranean was also studied for long-chain diols. For the Mozambique Channel, surface sediments of sites most proximal to Mozambique rivers showed the highest F1, 15 - C32 (up to 10 %). The sedimentary record shows high (15-35 %) pre-Holocene F1, 15 - C32 and low (soil and river-produced organic matter in the marine environment, which declines from 0.25 to 0.60 for the pre-Holocene to soil sources in the catchment area rather than a change in river influx. Like for the Mozambique Channel, a significant correlation between FC32 1, 15 and the BIT index (r2 = 0.38, p affected by riverine runoff but also by vegetation cover with increasing cover leading to lower soil erosion. Our results confirm that FC32 1, 15 is a complementary proxy for tracing riverine input of organic matter into marine shelf settings, and, in comparison with other proxies, it seems not to be affected by soil and vegetation changes in the catchment area.

  3. Improvements of palaeochemotaxonomy as a palaeofloristic proxy using artificial maturation of extant conifers

    Science.gov (United States)

    Lu, Y.; Hautevelle, Y.; Michels, R.

    2012-04-01

    Numerous studies of the molecular composition of terrestrial plants show that many organic compounds have a chemotaxonomic value. This means that these biomolecules are synthesized by a restricted number of taxa and can be used as specific biomarkers. Some of these biomolecules, like terpenoids, are poorly altered and preserved in sediments where they are then transformed into geomolecules. Thus, the distribution of vascular plant biomarkers preserved in sedimentary rocks could serve as proxy for terrestrial palaeoflora assessment. Furthermore, as flora association may reflect climatic conditions, vascular plant biomarkers may also serve as palaeoclimatic proxies. Botanical palaeochemotaxonomy presents some specific attributes compared to palaeobotany and palynology in the reconstruction of palaeofloristic and palaeoclimatic evolutions through geological time : 1) plant biomarkers are more widespread in the stratigraphic record than well preserved plant macrofossils, 2) on the contrary to palynomorphs they can be directly linked to specific plant taxa, 3) biomarkers are readily analyzed by usual organic geochemistry procedures. However, our knowledge in botanical palaeochemotaxonomy, allowing to link geomolecular markers to botanical taxa, is still incomplete. Difficulties are related to 1) extrapolation of information from extant plants to their fossil counterparts, 2) the scarcity of well preserved and identifiable fossils. In order to help fill these gaps, we use an experimental method based on artificial maturation of extant plants by confined pyrolysis (*Hautevelle et al. 2006). This technique allows to simulate conversion of biomolecules into diagenetized compounds. The objective of this study is to clarify the molecular signature of fossil conifer families. 69 species belonging to seven families of extant conifers (Araucariaceae, Cupressaceae, Pinaceae, Podocarpaceae, Sciadopityaceae, Taxaceae and Taxodiaceae) were pyrolyzed. Extractable organic matter is

  4. Enhanced Collaboration for Space Situational Awareness via Proxy Agents

    Science.gov (United States)

    Picciano, P.; Schurr, N.

    2012-09-01

    The call for dynamic partnerships demanded in the US. Space Policy confronts two formidable challenges. The first is evident in the lack of the adoption of technical innovations that could substantially enhance collaboration. The second category, and perhaps a greater impediment, involves organizational and social constraints that minimize information sharing. Compounding the technical challenges, the organizational barriers to collaboration present a different problem set. There is a culture in the space domain that predisposes most stakeholders to guard their information. Most owner/operators are reluctant to share asset data, whether experiencing an anomaly or just providing status updates. This is unfortunate, because the owner/operators generally have the most accurate and timely data pertaining to their satellite. Comprehensive Space Situational Awareness (SSA) requires the marshaling of disparate mission critical elements. The mission threads reliant on SSA are complex and often require analysis from a diverse team of experts with sophisticated systems and tools that may be dispersed across multiple entities including military, commercial, and public interests. Two significant trends are likely to further perpetuate this state of affairs: 1) the space environment continues to be more congested, contested, and competitive, and 2) further pressures to increase SSA Sharing with a greater number of stakeholders throughout the world. The challenge of delivering the right information to the right people, while protecting national security and privacy interests, is in need of an innovative solution. Our approach, entitled Space Collaboration via an Agent Network (SCAN), enables proxy software agents to represent stakeholders (as individuals and organizations) to enhance collaboration among various agency producers and consumers of space information The SCAN agent network will facilitate collaboration by identifying opportunities to collaborate, as well as optimize

  5. Apatite: a new redox proxy for silicic magmas?

    Science.gov (United States)

    Miles, Andrew; Graham, Colin; Hawkesworth, Chris; Gillespie, Martin; Bromiley, Geoff; Hinton, Richard

    2015-04-01

    Petrology, 89, 226-38. [2] Miles, A.J., Graham, C.M., Hawkesworth, C.J., Gillespie, M.R., Hinton, R.W., 2014, Mn in apatite: A new redox proxy for silicic magmas?: Geochimica et Cosmochimica Acta v. 132, p. 101-119.

  6. Hygroscopic growth and cloud droplet activation of xanthan gum as a proxy for marine hydrogels

    National Research Council Canada - National Science Library

    Dawson, K. W; Petters, M. D; Meskhidze, N; Petters, S. Suda; Kreidenweis, S. M

    2016-01-01

    .... Here we use xanthan gum (XG)—a bacterial biopolymer—as a proxy for marine hydrogels. Measurements were performed for pure XG particles and mixtures of XG with sodium chloride, calcium nitrate, and calcium carbonate...

  7. Middleware Proxy: A Request-Driven Messaging Broker For High Volume Data Distribution

    CERN Document Server

    Sliwinski, W; Dworak, A

    2014-01-01

    Nowadays, all major infrastructures and data centres (commercial and scientific) make an extensive use of the publish-subscribe messaging paradigm, which helps to decouple the message sender (publisher) from the message receiver (consumer). This paradigm is also heavily used in the CERN Accelerator Control system, in Proxy broker - critical part of the Controls Middleware (CMW) project. Proxy provides the aforementioned publish-subscribe facility and also supports execution of synchronous read and write operations. Moreover, it enables service scalability and dramatically reduces the network resources and overhead (CPU and memory) on publisher machine, required to serve all subscriptions. Proxy was developed in modern C++, using state of the art programming techniques (e.g. Boost) and following recommended software patterns for achieving low-latency and high concurrency. The outstanding performance of the Proxy infrastructure was confirmed during the last 3 years by delivering the high volume of LHC equipment...

  8. Youth proxy efficacy for fruit and vegetable availability varies by gender and socio-economic status.

    Science.gov (United States)

    Geller, Karly S; Dzewaltowski, David A

    2010-06-01

    The current study examined proxy efficacy, which was defined as youth's confidence to influence their parents to provide fruits and vegetables. The overall objective was to examine change in middle-school youth's proxy efficacy over time, and to determine if changes were moderated by gender and socio-economic status. Longitudinal cohort nested within schools. Eight middle schools located in urban, suburban and rural areas of a mid-western US state. Seven hundred and twelve youth followed across their 6th, 7th and 8th grade years. The sample was 51.8 % female, 30.5 % low socio-economic status and 89.5 % Caucasian, non-Hispanic. Males and lower socio-economic status youth were significantly lower in proxy efficacy at each assessment year compared with females and high socio-economic youth, respectively. Proxy efficacy to influence parents to provide fruits and vegetables may be an important construct to target in future interventions.

  9. Multiple water isotope proxy reconstruction of extremely low last glacial temperatures in Eastern Beringia (Western Arctic)

    NARCIS (Netherlands)

    Porter, Trevor J.; Froese, Duane G.; Feakins, Sarah J.; Bindeman, Ilya N.; Mahony, Matthew E.; Pautler, Brent G.; Reichart, Gert-Jan; Sanborn, Paul T.; Simpson, Myrna J.; Weijers, Johan W H

    2016-01-01

    Precipitation isotopes are commonly used for paleothermometry in high latitude regions. Here we present multiple water isotope proxies from the same sedimentary context - perennially frozen loess deposits in the Klondike Goldfields in central Yukon, Canada, representing parts of Marine Isotope

  10. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    Science.gov (United States)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2015-04-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  11. Human rights of children with intellectual disabilities: comparing self-ratings and proxy ratings.

    Science.gov (United States)

    Huus, K; Granlund, M; Bornman, J; Lygnegård, F

    2015-11-01

    A child rights-based approach to research articulates well with Article 12 of the United Nations Convention on the Rights of the Child (CRC) and highlights the importance and value of including children's own views about aspects that concern them. The aim of this study is to compare children with intellectual disability's own ratings (as self-raters) to those of their primary caregivers (as proxy raters) regarding human rights of children. The study also aims to establish whether there is an inter-rater agreement between the self-raters and proxy raters concerning Maslow's hierarchy of needs. This study is nested in a larger study examining the human rights of children with intellectual disability in South Africa. In total, 162 children with intellectual disability from 11 schools across three provinces and their primary caregivers participated by answering parts of a Children's Rights Questionnaire (CRQ) developed by the researchers based on the United Nation's CRC. We compared the answers for six questions in the questionnaire that were addressed to self-raters (children) and proxy raters (primary caregivers) in the same way. Questions regarding basic needs, such as access to clean water or whether the child had food to eat at home, were answered similarly by self-raters and proxy raters. Larger differences were found when self-raters and proxy raters were asked about whether the child had things or friends to play with at home. Socio-economic variables seemed to affect whether self-raters and proxy raters answered similarly. The results underscore the importance of promoting children's rights to express themselves by considering the opinions of both the children as self-raters and their primary caregivers as proxy raters - not only the latter. The results indicate that it is especially important to include children's own voices when more complex needs are surveyed. Agreement between self- and proxy ratings could be affected by socio-economic circumstances.

  12. Design and implementation of Ad-Hoc collaborative proxying scheme for reducing network energy waste

    OpenAIRE

    Rafiullah Khan; Sarmad Ullah Khan

    2017-01-01

    Network devices are equipped with low power states but they are rarely activated due to their inability of maintaining network connectivity. Recently, Network Connectivity Proxy (NCP) concept has been proposed in literature as an effective mechanism to exploit full potential of low power features on network devices by impersonating their virtual presence. However, the NCP concept faces several open issues and challenges especially related to proxying of TCP connections and majority of daily u...

  13. Similarity, agreement, and assumed similarity in proxy end-of-life decision making.

    Science.gov (United States)

    McDade-Montez, Elizabeth; Watson, David; Beer, Andrew

    2013-12-01

    Medical decisions near the end of life are often made by proxies who can be inaccurate in their judgments of patient preferences. Given that accuracy in surrogate decision making is an important goal in end-of-life decision making, and in light of that previously seen levels of accuracy reflect substantial disagreement, error, or both, this study examined both relationship and individual factors that potentially affect surrogate accuracy. Specifically, this study examined similarity, agreement, and assumed similarity-a process whereby raters use their own traits and preferences to rate another person-in spousal ratings of end-of-life treatment. This study expands on previous research by examining the potential influence of relationship factors and assumed similarity on end-of-life decision making among a sample of newlyweds. Newly married couples (n = 197) completed self and spouse measures of hypothetical end-of-life preferences and scales assessing marital satisfaction, personality, and attitudes. Results indicate a moderate level of similarity on husband and wife self-rated end-of-life treatment preferences (rs = .18-.29) and a moderate level of agreement between self and proxy ratings (rs = .17-.41). The largest correlations were seen between self ratings and proxy ratings (e.g., husband self ratings and husband proxy ratings of wife preferences, rs = .46-.69), reflecting strong assumed similarity in proxy ratings. For wives, similarity with husbands on a few attitudinal variables (i.e., spirituality, moral strictness, and conservatism) influenced proxy accuracy. Recognizing the potential impact of personal preferences on proxy ratings, as well as the potential influence of relationship factors, may help improve proxy accuracy and end-of-life care for patients and families.

  14. Contribution in Adaptating Web Interfaces to any Device on the Fly: The HCI Proxy

    Science.gov (United States)

    Lardon, Jérémy; Fayolle, Jacques; Gravier, Christophe; Ates, Mikaël

    2008-11-01

    Lot of work has been done on the adaptation of UIs. In the particular field of Web UI adaptation, many research projects aim at displaying web content designed for PCs on poorer supports. In this paper, we present previous work in the domain and then our proxy architecture, HCI proxy, to test solutions for the problem of adapting Web UIs for mobile phones, PDA and smartphones but also for TVs through browser-embedding STBs, and this on the fly.

  15. The suitability of Mytilus edulis as proxy archive and its response to ocean acidification

    OpenAIRE

    Heinemann, Agnes

    2011-01-01

    Past climate changes can be used as indicators of future scenarios, however past climatic changes can not be directly observed. Therefore, the reconstruction of past abiotic conditions can approximated using chemical or isotopic proxies. These proxies can be measured in natural archives (e.g. bivalve shells and coral skeletons). One aspect of current climate change is the acidification of the oceans, a phenomenon caused by the oceanic uptake of anthropogenic CO2 and a resulting shift in the m...

  16. Proxy-based Video Transmission: Error Resiliency, Resource Allocation, and Dynamic Caching

    OpenAIRE

    Tu, Wei

    2009-01-01

    In this dissertation, several approaches are proposed to improve the quality of video transmission over wired and wireless networks. To improve the robustness of video transmission over error-prone mobile networks, a proxy-based reference picture selection scheme is proposed. In the second part of the dissertation, rate-distortion optimized rate adaptation algorithms are proposed for video applications over congested network nodes. A segment-based proxy caching algorithm for video-on-demand a...

  17. Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy.

    Science.gov (United States)

    Clemence, Caulle; Meryem, Mojtahid; Karoliina, Koho; Andy, Gooday; Gert-Jan, Reichart; Gerhard, Schmiedl; Frans, Jorissen

    2014-05-01

    Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy. C. Caulle1, M. Mojtahid1, K. Koho2,3, A. Gooday4, G. J. Reichart2,3, G. Schmiedl5, F. Jorissen1 1UMR CNRS 6112 LPG-BIAF, University of Angers, 2 bd Lavoisier, 49045 Angers Cedex 2Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Budapestlaan 4, 3584 CD Utrecht, The Netherlands 3Royal Netherland Institute for Sea Research (Royal NIOZ), Landsdiep 4, 1797 SZ 't Horntje (Texel) 4Southampton Oceanography Centre, Empress Dock, European Way, Southampton SO14 3ZH, UK 5Department of Geosciences, University of Hamburg, Bundesstraße 55, 20146 Hamburg, Germany The thermohaline circulation oxygenates the deep ocean sediment and therefore enables aerobic life on the sea-floor. In the past, interruption of this deep water formation occurred several times causing hypoxic to anoxic conditions on the sea-floor leading to major ecological turnover. A better understanding of the interaction between climate and bottom water oxygenation is therefore essential in order to predict future oceanic responses. Presently, permanent (stable over decadal timescale) low-oxygen conditions occur naturally at mid-water depths in the northern Indian Ocean (Arabian Sea). Oxygen Minimum Zones (OMZ) are key areas to understand the hypoxic-anoxic events and their impact on the benthic ecosystem. In this context, a good knowledge of the ecology and life cycle adaptations of the benthic foraminiferal assemblages living in these low oxygen areas is essential. A series of multicores were recovered from three transects showing an oxygen gradient across the OMZ: the Murray Ridge, the Oman margin and the Indian margin. The stations located at the same depths showed slightly different oxygen concentrations and large differences in organic matter content. These differences are mainly related to the geographic location in the Arabian Sea. We investigated at these stations live and dead benthic

  18. Applying a family systems lens to proxy decision making in clinical practice and research.

    Science.gov (United States)

    Rolland, John S; Emanuel, Linda L; Torke, Alexia M

    2017-03-01

    When patients are incapacitated and face serious illness, family members must make medical decisions for the patient. Medical decision sciences give only modest attention to the relationships among patients and their family members, including impact that these relationships have on the decision-making process. A review of the literature reveals little effort to systematically apply a theoretical framework to the role of family interactions in proxy decision making. A family systems perspective can provide a useful lens through which to understand the dynamics of proxy decision making. This article considers the mutual impact of family systems on the processes and outcomes of proxy decision making. The article first reviews medical decision science's evolution and focus on proxy decision making and then reviews a family systems approach, giving particular attention to Rolland's Family Systems Illness Model. A case illustrates how clinical practice and how research would benefit from bringing family systems thinking to proxy decisions. We recommend including a family systems approach in medical decision science research and clinical practices around proxy decisions making. We propose that clinical decisions could be less conflicted and less emotionally troubling for families and clinicians if family systems approaches were included. This perspective opens new directions for research and novel approaches to clinical care. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Cryptanalysis and Performance Evaluation of Enhanced Threshold Proxy Signature Scheme Based on RSA for Known Signers

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    Raman Kumar

    2013-01-01

    Full Text Available In these days there are plenty of signature schemes such as the threshold proxy signature scheme (Kumar and Verma 2010. The network is a shared medium so that the weakness security attacks such as eavesdropping, replay attack, and modification attack. Thus, we have to establish a common key for encrypting/decrypting our communications over an insecure network. In this scheme, a threshold proxy signature scheme based on RSA, any or more proxy signers can cooperatively generate a proxy signature while or fewer of them cannot do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers (Rivest et al., 1978. Comparison is done on the basis of time complexity, space complexity, and communication overhead. We compare the performance of four schemes (Hwang et al. (2003, Kuo and Chen (2005, Yong-Jun et al. (2007, and Li et al. (2007, with the performance of a scheme that has been proposed earlier by the authors of this paper. In the proposed scheme, both the combiner and the secret share holder can verify the correctness of the information that they are receiving from each other. Therefore, the enhanced threshold proxy signature scheme is secure and efficient against notorious conspiracy attacks.

  20. CAN ACCOUNTING INFORMATION ACT AS A PROXY FOR EX ANTE UNCERTAINTY IN INITIAL PUBLIC OFFERINGS?

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    Tatang Ary Gumanti

    2003-06-01

    Full Text Available This paper reviews and summarizes previous works and the rationale for the proposition that accounting information is in fact value relevant in the determination of an initial public offering IPO.Theoretical and empirical evidence has indicated that certain accounting measures can he used as proxies for total firm risk, that is, they could determine the riskiness of a corporation. The literature also advocates that accounting information is relevant in determining the value and thus the riskiness of a corporation through the use of accounting analysis. Since most of the information available in the prospectus is accounting information, it is arguable that this information represents a potential source for assessing the issuing firm. Some scholars have also advocated the possibility of using accounting information in assessing the value of firm making an IPO. Numerous papers have provided analytical and empirical evidence of the association between accounting numbers and the value of IPOs. The conclusion generally comes to show that information in the prospectus is value relevant concerning the IPO. The paper shows that it is indeed an arguable to use accounting information in the valuation of an IPO. Accordingly, it is an empirical issue whether accounting information has the property in explaining the ex-ante uncertainty of an IPO.

  1. The “Serpentine Syndrome” (H. Jenny, 1980: A Proxy for Soil Remediation

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    Claudio Bini

    2014-12-01

    Full Text Available Serpentine soils have relatively high concentrations of PTEs (Co, Cr, Cu, Fe, Ni but generally low amounts of major nutrients. They often bear a distinctive vegetation, and a frequently-used approach to understanding serpentine ecology and related environmental hazard has been the chemical analysis of soils and plants. In this paper we report past and current studies on serpentine soils and serpentinophytes. The serpentine vegetation differs from the conterminous non-serpentine areas, being often endemic, and showing macroscopic physionomical characters. Similarly, at microscopic level cytomorphological characteristics of the roots and variations in biochemical parameters were recorded in serpentinophytes. Light microscopy observations showed depressed mitotic activity in the meristematic zone, and consequent reduced root growth. The different tolerance mechanisms responsible for plant adaption to high concentrations of PTEs in serpentine soils can be related to the capacity of plants to limit metal uptake and translocation. The majority of serpentinophytes tend to limit metal absorption to roots: the cell wall constitutes a barrier against metal penetration inside plant tissues. Only a few species are able to accumulate metals in their aerial parts, acting a tolerance mechanism to very high metal concentrations. Serpentinophytes, therefore, could represent proxies for plants  used in remediation of metal-contaminated soils and in phytomining as well.

  2. Sensor proxy mobile IPv6 (SPMIPv6)--a novel scheme for mobility supported IP-WSNs.

    Science.gov (United States)

    Islam, Md Motaharul; Huh, Eui-Nam

    2011-01-01

    IP based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health-care, home automation, environmental monitoring, industrial control, vehicle telematics and agricultural monitoring. In all these applications, mobility in the sensor network with special attention to energy efficiency is a major issue to be addressed. Host-based mobility management protocols are not suitable for IP-WSNs because of their energy inefficiency, so network based mobility management protocols can be an alternative for the mobility supported IP-WSNs. In this paper we propose a network based mobility supported IP-WSN protocol called Sensor Proxy Mobile IPv6 (SPMIPv6). We present its architecture, message formats and also evaluate its performance considering signaling cost, mobility cost and energy consumption. Our analysis shows that with respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 60% and 56%, as well as the mobility cost by 62% and 57%, compared to MIPv6 and PMIPv6, respectively. The simulation results also show that in terms of the number of hops, SPMIPv6 decreases the signaling cost by 56% and 53% as well as mobility cost by 60% and 67% as compared to MIPv6 and PMIPv6 respectively. It also indicates that proposed scheme reduces the level of energy consumption significantly.

  3. The dendroclimatic proxies from the northern Quebec taiga in the PAGES 2K network: recent advances and future developments.

    Science.gov (United States)

    Gennaretti, Fabio; Naulier, Maud; Arseneault, Dominique; Savard, Martine; Bégin, Christian; Boucher, Etienne; Bégin, Yves; Guiot, Joël

    2016-04-01

    Northeastern North America was historically underrepresented in the network of climate proxies used for climate reconstructions over the last two millennia. Indeed, in North America most high-resolution climate proxies are long tree-ring chronologies but, in Northeastern North America, these chronologies are highly challenging due to short tree longevity, high frequency and severity of wildfires and remoteness of many areas. Here, we will present the efforts accomplished during the last decade by our team in developing millennial-long tree-ring chronologies in the northern Quebec taiga. We sampled black spruce [Picea mariana (Mill.) B.S.P] subfossil tree remains naturally fallen in the littoral zone of six lakes to build six site-specific ring-width chronologies as well as two chronologies of stable isotope ratios (δ18O and δ13C in tree-ring cellulose). These chronologies, which are now included in the PAGES 2K network, were independently used to reconstruct summer temperature variations showing a well-expressed Medieval Climate Anomaly and the impact of volcanic and solar forcings at regional scale. We will also discuss non-climatic influences on these chronologies (i.e. wildfires and sampling height inconsistency), as well as the ongoing effort to extend the reconstructions in time to cover the last 2500 years. Finally, a new European funded project called MAIDEN-SPRUCE will be introduced. Within MAIDEN-SPRUCE, we will use a data-model approach to improve our understanding of the links between forests and climate over the last millennium. More specifically, we will adapt the process-based ecophysiological model MAIDENiso to investigate factors influencing the growth and underlying biogeochemical processes of black spruce. One of our objectives is to provide the first multi-proxy (ring widths and δ18O and δ13C in tree-ring cellulose) regional climate reconstruction in Eastern North America over the last millennium taking into account mechanistic rules

  4. Stable isotope and trace element proxy data from aragonite cements of stressed reef environments (early Messinian, Mediterranean Region)

    Science.gov (United States)

    Brachert, Thomas; Bosellini, Francesca R.; Reuter, Markus; Mertz-Kraus, Regina; Vescogni, Alessandro

    2010-05-01

    Early Messinian coral reefs of the Mediterranean area are among the classical examples of Neogene reefs in the world and, according to the ecology of their biota, do not exhibit compelling evidence for significant salinity stress prior to the Messinian Salinity Crisis (MSC). Because of excellent outcrop conditions and preservation, these reefs have become prototypes of Neogene reefs worldwide. Here we present stable oxygen isotope (IRMS) and trace element data (LA-ICP-MS) from marine aragonite cement in biogenic frameworks of some Mediterranean reefs. The reworking of the cements by intraformational breccias clearly supports petrographic evidence of "syndepositional" precipitation. Reported values of 18O/16O translate into peak sea surface salinity of 50 to 60 permil, which is a lethal value for most members of the reef community. Therefore, additional proxies have been evaluated to constrain the environment in which the cements formed. 13C/12C signatures are fully within the range of marine cement, however, systematic excursions exist on outcrop-scaple over the geological sections which may suggest episodic influx of terrestrial organic matter brought in by rivers or episodic upwelling of deep water masses with CO2 enriched in 12C. Intra-cement 13C/12C, Sr/Ca and Mg/Ca measured along transects exhibits co-variant changes which are incompatible with temperature effects and more plausibly document the mixing of different fluids, or the evolution of the pore fluids upon continuing precipitation. Although the final cause underlying the discrepant aspect of biological and various inorganic proxy data remains not yet fully understood, this study shows that evaluation of one single proxy may lead to more misleading than helpful concepts of palaeoenvironments and environment change.

  5. Multi-proxy reconstructions of May–September precipitation field in China over the past 500 years

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    F. Shi

    2017-12-01

    Full Text Available The dominant modes of variability of precipitation for the whole of China over the past millennium and the mechanism governing their spatial structure remain unclear. This is mainly due to insufficient high-resolution proxy records of precipitation in western China. Numerous tree-ring chronologies have recently been archived in publicly available databases through PAGES2k activities, and these provide an opportunity to refine precipitation field reconstructions for China. Based on 479 proxy records, including 371 tree-ring width chronologies, a tree-ring isotope chronology, and 107 drought/flood indices, we reconstruct the precipitation field for China for the past half millennium using the optimal information extraction method. A total of 3631 of 4189 grid points in the reconstruction field passed the cross-validation process, accounting for 86.68 % of the total number of grid points. The first leading mode of variability of the reconstruction shows coherent variations over most of China. The second mode is a north–south dipole in eastern China characterized by variations of the same sign in western China and northern China (except for Xinjiang province. It is likely controlled by the El Niño–Southern Oscillation (ENSO variability. The third mode is a sandwich triple mode in eastern China including variations of the same sign in western China and central China. The last two modes are reproduced by most of the six coupled climate models' last millennium simulations performed in the framework of the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3. In particular, the link of the second mode with ENSO is confirmed by the models. However, there is a mismatch between models and proxy reconstructions in the time development of different modes. This mismatch suggests the important role of internal variability in the reconstructed precipitation mode variations of the past 500 years.

  6. Secure Service Proxy: A CoAP(s) Intermediary for a Securer and Smarter Web of Things.

    Science.gov (United States)

    Van den Abeele, Floris; Moerman, Ingrid; Demeester, Piet; Hoebeke, Jeroen

    2017-07-11

    As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP): a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things.

  7. Secure Service Proxy: A CoAP(s Intermediary for a Securer and Smarter Web of Things

    Directory of Open Access Journals (Sweden)

    Floris Van den Abeele

    2017-07-01

    Full Text Available As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP: a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things.

  8. Secure Service Proxy: A CoAP(s) Intermediary for a Securer and Smarter Web of Things

    Science.gov (United States)

    Van den Abeele, Floris; Moerman, Ingrid; Demeester, Piet

    2017-01-01

    As the IoT continues to grow over the coming years, resource-constrained devices and networks will see an increase in traffic as everything is connected in an open Web of Things. The performance- and function-enhancing features are difficult to provide in resource-constrained environments, but will gain importance if the WoT is to be scaled up successfully. For example, scalable open standards-based authentication and authorization will be important to manage access to the limited resources of constrained devices and networks. Additionally, features such as caching and virtualization may help further reduce the load on these constrained systems. This work presents the Secure Service Proxy (SSP): a constrained-network edge proxy with the goal of improving the performance and functionality of constrained RESTful environments. Our evaluations show that the proposed design reaches its goal by reducing the load on constrained devices while implementing a wide range of features as different adapters. Specifically, the results show that the SSP leads to significant savings in processing, network traffic, network delay and packet loss rates for constrained devices. As a result, the SSP helps to guarantee the proper operation of constrained networks as these networks form an ever-expanding Web of Things. PMID:28696393

  9. Luminescence signal profiling: a new proxy for sedimentologically "invisible" marine Mass Transport Deposits (MTDs)

    Science.gov (United States)

    López, Gloria I.; Bialik, Or; Waldmann, Nicolas

    2017-04-01

    obtained on both, already split-opened cores. Both cores depicted the monotonous characteristics of homogeneousness down-core as per most of the results obtained from the non-destructive and destructive tests. One of the cores showed several small higher energy events, including a Mass Transport Deposit (MTD) within its first 10 cm, only fully visible on the CT scan imaging, the PPSL profile and particle size distribution plot. This initial investigation demonstrates the feasibility and usefulness of luminescence profiling as a new sedimentological and petrophysical proxy to better visualize homogeneous yet complex, fine-grained, underwater archives. Moreover, it helps to understand the continuity of the stratigraphy and linearity of deposition of the sediment, besides assisting on the estimation of relative ages provided that good OSL ages are obtained throughout the recovered archive.

  10. WOOD CELLULAR DENDROCLIMATOLOGY: TESTING NEW PROXIES IN GREAT BASIN BRISTLECONE PINE

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    Emanuele Ziaco

    2016-10-01

    Full Text Available Dendroclimatic proxies can be generated from the analysis of wood cellular structures, allowing for a more complete understanding of the physiological mechanisms that control the climatic response of tree species. Century-long (1870-2013 time series of anatomical parameters were developed for Great Basin bristlecone pine (Pinus longaeva D.K. Bailey by capturing strongly contrasted microscopic images through a Confocal Laser Scanning Microscope. Environmental information embedded in wood anatomical series was analyzed in comparison with ring-width series using measures of empirical signal strength. Response functions were calculated against monthly climatic variables to evaluate climate sensitivity of cellular features (e.g. lumen area; lumen diameter for the period 1950-2013. Calibration-verification tests were used to determine the potential to generate long climate reconstructions from these anatomical proxies. A total of eight tree-ring parameters (two ring-width and six chronologies of xylem anatomical parameters were analyzed. Synchronous variability among samples varied among tree-ring parameters, usually decreasing from ring width to anatomical features. Cellular parameters linked to plant hydraulic performance (e.g. tracheid lumen area and radial lumen diameter showed empirical signal strength similar to ring-width series, while noise was predominant in chronologies of lumen tangential width and cell-wall thickness. Climatic signals were different between anatomical and ring-width chronologies, revealing a positive and temporally stable correlation of tracheid size (i.e. lumen and cell diameter with monthly (i.e. March and seasonal precipitation. In particular, tracheid lumen diameter emerged as a reliable moisture indicator and was then used to reconstruct total March-August precipitation from 1870 to 2013. Wood anatomy holds great potential to refine and expand dendroclimatic records by allowing estimates of plant physiological

  11. On the uncertainties associated with using gridded rainfall data as a proxy for observed

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    C. R. Tozer

    2012-05-01

    Full Text Available Gridded rainfall datasets are used in many hydrological and climatological studies, in Australia and elsewhere, including for hydroclimatic forecasting, climate attribution studies and climate model performance assessments. The attraction of the spatial coverage provided by gridded data is clear, particularly in Australia where the spatial and temporal resolution of the rainfall gauge network is sparse. However, the question that must be asked is whether it is suitable to use gridded data as a proxy for observed point data, given that gridded data is inherently "smoothed" and may not necessarily capture the temporal and spatial variability of Australian rainfall which leads to hydroclimatic extremes (i.e. droughts, floods. This study investigates this question through a statistical analysis of three monthly gridded Australian rainfall datasets – the Bureau of Meteorology (BOM dataset, the Australian Water Availability Project (AWAP and the SILO dataset. The results of the monthly, seasonal and annual comparisons show that not only are the three gridded datasets different relative to each other, there are also marked differences between the gridded rainfall data and the rainfall observed at gauges within the corresponding grids – particularly for extremely wet or extremely dry conditions. Also important is that the differences observed appear to be non-systematic. To demonstrate the hydrological implications of using gridded data as a proxy for gauged data, a rainfall-runoff model is applied to one catchment in South Australia initially using gauged data as the source of rainfall input and then gridded rainfall data. The results indicate a markedly different runoff response associated with each of the different sources of rainfall data. It should be noted that this study does not seek to identify which gridded dataset is the "best" for Australia, as each gridded data source has its pros and cons, as does gauged data. Rather, the intention is

  12. Origin and applicability of tetraether membrane lipids as temperature proxies in French peri-urban lakes

    Science.gov (United States)

    Mainié, François; Huguet, Arnaud; Breban, Alice; Lacroix, Gérard; Anquetil, Christelle; Derenne, Sylvie

    2015-04-01

    The Ile-de-France region is the most populated area in France, with ca. 12 million inhabitants, i.e. about 20 % of French population. The peri-urban aquatic ecosystems of this region are impacted by a large variety of environmental stressors, and especially high anthropogenic pressures (agricultural, industrial and urban pollutants), leading to the increased eutrophication of these water systems. The Ile-de-France lakes are therefore highly vulnerable ecosystems. Over the last years, several environmental markers have been developed to better understand the functioning of aquatic ecosystems, including the so-called GDGTs (glycerol dialkyl glycerol tetraethers). GDGTs are membrane lipids produced by archaea and some unknown bacteria, which are increasingly used to reconstruct mean annual air and surface water temperature as well as pH. These compounds are ubiquitous in terrestrial and aquatic environments, but their origin and applicability as temperature and pH proxies in lakes, especially highly polluted ones, need further investigation. In this study, GDGTs were analysed in 33 lakes from the Ile-de-France region, representing the diversity of the regional landscape and characterised by different levels of eutrophication. The abundance and distribution of GDGTs in lacustrine sediments and surrounding soils were compared. Bacterial GDGTs were systematically much more abundant in sediments than in soils and displayed different distributions in the two types of environments, showing that they are mainly produced in situ in lakes, in the water column and/or sediment. Similarly, the concentration in archaeal GDGTs was much higher in sediments than in soils and the distribution of these compounds differed between soils and sediments, implying that the predominant archaeal communities are not the same in the two environments. When the lakes are distinguished by their eutrophication level, the latter was shown for the first time to have an impact on the microorganisms

  13. Variability in Bias of Gridded Sea Surface Temperature Data Products: Implications for Seasonally Resolved Marine Proxy Reconstructions

    Science.gov (United States)

    Ouellette, G., Jr.; DeLong, K. L.

    2016-12-01

    cautionary note against the wholesale use of a particular gridded data product for marine proxy calibration, whether for a single site or larger regional reconstruction, without considering the inherent heterogeneous bias present in each data product that we show varies among locations. Furthermore, this study has implications for comparing climate models and these SST data products.

  14. Lithium isotopes in foraminifera shells as a novel proxy for the ocean dissolved inorganic carbon (DIC)

    Science.gov (United States)

    Vigier, Nathalie; Rollion-Bard, Claire; Levenson, Yaël; Erez, Jonathan

    2015-01-01

    Past ocean pH and pCO2 are critical parameters for establishing relationships between Earth's climate and the carbon cycle. Previous pCO2 estimates are associated with large uncertainties and are debated. In this study, laboratory cultures of the foraminiferan genus Amphistegina were performed in order to examine the possible factors that control the Li isotope composition (δ7Li) of their shells. δ7Li is insensitive to temperature and pH variations but correlates positively with the Dissolved Inorganic Carbon (DIC) of seawater. Li/Ca ratio in the shells shows negative correlation with δ7Li, consistent with published data for planktonic foraminifera from core tops and from short periods during the Cenozoic. We propose that the sensitivity of δ7Li and Li/Ca ratio to DIC is a biological phenomenon and is related to biomineralization mechanisms in foraminifera. We used the published foraminiferal δ7Li records, and our experimental results, to determine the paleo-ocean DIC and pH for the last glacial-interglacial cycle. The results are consistent with published estimates of pH and pCO2 based on boron isotopes and ice cores. We suggest Li and its isotopes may serve as a new complementary proxy for the paleo-ocean carbonate chemistry.

  15. A millennial multi-proxy reconstruction of summer PDSI for Southern South America

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    É. Boucher

    2011-08-01

    Full Text Available We present the first spatially explicit field reconstruction of the summer (DJF Palmer Drought Severity Index (PDSI for the Southern Hemisphere. Our multi-proxy reconstruction focuses on Southern South America (SSA, south of 20° S and is based on a novel spectral analogue method that aims at reconstructing low PDSI frequencies independently from higher frequencies. The analysis of past regimes and trends in extreme wet spells and droughts reveals considerable geographical and temporal variations over the last millennium in SSA. Although recent changes are in some cases notorious, most were not exceptional at the scale of the last thousand years. Our reconstruction highlights that low frequency water availability fluctuations in Patagonia were generally in antiphase with the rest of the subcontinent. Providing the fact that modern patterns of changes are transferable to the past, we show that such antiphases within SSA's hydroclimate could be attributed to the spatially contrasted response of summer PDSI to the Antarctic Oscillation (AAO. However, El Niño Southern Oscillation (ENSO and Pacific Decadal Oscillation (PDO signals are also embedded within the PDSI series during the 20th century. All these ocean-atmospheric forcings acted synergically, but the dominant influence appeared highly compartmentalized through space, highlighting clear AAO- (e.g. South Patagonia and ENSO- (e.g. the Pampas dominated regions. Our results therefore emphasize the complexity of water-availability fluctuations in SSA and their important dependence on external ocean-atmospheric forcings.

  16. Penguin tissue as a proxy for relative krill abundance in East Antarctica during the Holocene.

    Science.gov (United States)

    Huang, Tao; Sun, Liguang; Long, Nanye; Wang, Yuhong; Huang, Wen

    2013-09-30

    Antarctic krill (Euphausia superba) is a key component of the Southern Ocean food web. It supports a large number of upper trophic-level predators, and is also a major fishery resource. Understanding changes in krill abundance has long been a priority for research and conservation in the Southern Ocean. In this study, we performed stable isotope analyses on ancient Adélie penguin tissues and inferred relative krill abundance during the Holocene epoch from paleodiets of Adélie penguin (Pygoscelis adeliae), using inverse of δ¹⁵N (ratio of ¹⁵N/¹⁴N) value as a proxy. We find that variations in krill abundance during the Holocene are in accord with episodes of regional climate changes, showing greater krill abundance in cold periods. Moreover, the low δ¹⁵N values found in modern Adélie penguins indicate relatively high krill availability, which supports the hypothesis of krill surplus in modern ages due to recent hunt for krill-eating seals and whales by humans.

  17. Night-time lights as a proxy of human pressure on freshwater resources

    Science.gov (United States)

    Ceola, Serena; Montanari, Alberto; Laio, Francesco

    2017-04-01

    The presence and availability of freshwater resources at the global scale control the dynamics and the biodiversity of river ecosystems, as well as the human development and the security of people and economies. The increasing human pressure on freshwater is known to potentially drive significant alterations on both ecohydrological and social dynamics. To date, a spatially-detailed snapshot (i.e. single in time) analysis of human water security and river biodiversity threats revealed that the majority of the world's population and river ecosystems are exposed to high levels of endangerment. However, the temporal evolution of these effects at the global scale is still unexplored. To this aim, moving from the recent progress on remote sensing techniques, we employed yearly averaged night-time light images available from 1992 to 2013 as a proxy of anthropogenic presence and activity and we investigated how threats to human water security and river biodiversity evolved in time in 405 major river basins. Our results show a consistent correlation between nightlights and ecohydrological and threats, providing innovative support for freshwater resources management.

  18. Proxy evidence from Chew Bahir (Ethiopia) that environmental change promoted human dispersal out of Northeast Africa

    Science.gov (United States)

    Viehberg, Finn; Just, Janna; Dean, Jonathan; Asrat, Asfawossen; Claussen, Martin; Franz, Sven-Oliver; Klasen, Nicole; Kleinen, Thomas; Lamb, Henry; Leng, Melanie J.; Ludwig, Patrick; Milodowski, Antoni E.; Rethemeyer, Janet; Schäbitz, Frank; Wagner, Bernd

    2017-04-01

    The Chew Bahir rift between the Main Ethiopian Rift (MER) and the Kenyan Rift and is filled with up to 5 km of sediment. It is a failed rift located within the Miocene-aged Broadly Rifted Zone of Southern Ethiopia marking the transition between the active MER to the north and the Turkana Basin to the south. The study site is in the prominent corridor from the source area of the anatomically modern humans to the Arabian peninsula and Levant. Proxy records from lake sediments drilled in the Chew Bahir basin (Ethiopia), close to the key hominin site of Omo-Kibish, show two distinct hydroclimatic phases. An initial period between 120 to 75 kyr, with highly variable conditions with rapid shifts from very wet to extreme aridity, is coincident with the east 'African megadroughts' period. This is followed by a more stable hydroclimate interval between 62 to 32 kyr, which is then followed by the onset of the Late Glacial maximum and later the North African Humid Period. In between these two distinct climatic periods is a gradual shift to drier conditions with an extreme drought at 62 kyr. We propose that this shift, from more to less variable hydroclimate, may help account for the anatomically modern human dispersal events out of Africa from <62 kyr.

  19. Daily mood ratings via text message as a proxy for clinic based depression assessment.

    Science.gov (United States)

    Aguilera, Adrian; Schueller, Stephen M; Leykin, Yan

    2015-04-01

    Mobile and automated technologies are increasingly becoming integrated into mental health care and assessment. The purpose of this study was to determine how automated daily mood ratings are related to the Patient Health Questionnaire-9 (PHQ-9), a standard measure in the screening and tracking of depressive symptoms. There was a significant relationship between daily mood scores and PHQ-9 scores, and between one-week average mood scores and PHQ-9 scores, controlling for linear change in depression scores. PHQ-9 scores were not related to the average of two week mood ratings. This study also constructed models using variance, maximum, and minimum values of mood ratings in the preceding week and two-week periods as predictors of PHQ-9. None of these variables significantly predicted PHQ-9 scores when controlling for daily mood ratings and the corresponding averages for each period. This study only assessed patients who were in treatment for depression, therefore findings might not generalize to the relationship between text message mood ratings for those who are not depressed. The sample was also predominantly Spanish speaking and low-income making generalizability to other populations uncertain. Our results show that automatic text message based mood ratings can be a clinically useful proxy for the PHQ-9. Importantly, this approach avoids the limitations of the PHQ-9 administration, which include length and a higher requirement for literacy. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Mobile phone call data as a regional socio-economic proxy indicator.

    Directory of Open Access Journals (Sweden)

    Sanja Šćepanović

    Full Text Available The advent of publishing anonymized call detail records opens the door for temporal and spatial human dynamics studies. Such studies, besides being useful for creating universal models for mobility patterns, could be also used for creating new socio-economic proxy indicators that will not rely only on the local or state institutions. In this paper, from the frequency of calls at different times of the day, in different small regional units (sub-prefectures in Côte d'Ivoire, we infer users' home and work sub-prefectures. This division of users enables us to analyze different mobility and calling patterns for the different regions. We then compare how those patterns correlate to the data from other sources, such as: news for particular events in the given period, census data, economic activity, poverty index, power plants and energy grid data. Our results show high correlation in many of the cases revealing the diversity of socio-economic insights that can be inferred using only mobile phone call data. The methods and the results may be particularly relevant to policy-makers engaged in poverty reduction initiatives as they can provide an affordable tool in the context of resource-constrained developing economies, such as Côte d'Ivoire's.

  1. Hey Teacher, Your Personality's Showing!

    Science.gov (United States)

    Paulsen, James R.

    1977-01-01

    A study of 30 fourth, fifth, and sixth grade teachers and 300 of their students showed that a teacher's age, sex, and years of experience did not relate to students' mathematics achievement, but that more effective teachers showed greater "freedom from defensive behavior" than did less effective teachers. (DT)

  2. Planning a Successful Tech Show

    Science.gov (United States)

    Nikirk, Martin

    2011-01-01

    Tech shows are a great way to introduce prospective students, parents, and local business and industry to a technology and engineering or career and technical education program. In addition to showcasing instructional programs, a tech show allows students to demonstrate their professionalism and skills, practice public presentations, and interact…

  3. Risk Aversion in Game Shows

    DEFF Research Database (Denmark)

    Andersen, Steffen; Harrison, Glenn W.; Lau, Morten I.

    2008-01-01

    We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games......, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  4. Measuring performance at trade shows

    DEFF Research Database (Denmark)

    Hansen, Kåre

    2004-01-01

    Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...... of the scale's reliability, factor structure, and validity on the basis of analyzing data from independent samples of exhibitors at the international trade shows SIAL (Paris) and ANUGA (Cologne); and it concludes with a discussion of potential managerial applications and implications for future research. New...

  5. Tokyo Motor Show 2003; Tokyo Motor Show 2003

    Energy Technology Data Exchange (ETDEWEB)

    Joly, E.

    2004-01-01

    The text which follows present the different techniques exposed during the 37. Tokyo Motor Show. The report points out the great tendencies of developments of the Japanese automobile industry. The hybrid electric-powered vehicles or those equipped with fuel cells have been highlighted by the Japanese manufacturers which allow considerable budgets in the research of less polluting vehicles. The exposed models, although being all different according to the manufacturer, use always a hybrid system: fuel cell/battery. The manufacturers have stressed too on the intelligent systems for navigation and safety as well as on the design and comfort. (O.M.)

  6. Statistical framework for evaluation of climate model simulations by use of climate proxy data from the last millennium – Part 2: A pseudo-proxy study addressing the amplitude of solar forcing

    Directory of Open Access Journals (Sweden)

    A. Hind

    2012-08-01

    Full Text Available The statistical framework of Part 1 (Sundberg et al., 2012, for comparing ensemble simulation surface temperature output with temperature proxy and instrumental records, is implemented in a pseudo-proxy experiment. A set of previously published millennial forced simulations (Max Planck Institute – COSMOS, including both "low" and "high" solar radiative forcing histories together with other important forcings, was used to define "true" target temperatures as well as pseudo-proxy and pseudo-instrumental series. In a global land-only experiment, using annual mean temperatures at a 30-yr time resolution with realistic proxy noise levels, it was found that the low and high solar full-forcing simulations could be distinguished. In an additional experiment, where pseudo-proxies were created to reflect a current set of proxy locations and noise levels, the low and high solar forcing simulations could only be distinguished when the latter served as targets. To improve detectability of the low solar simulations, increasing the signal-to-noise ratio in local temperature proxies was more efficient than increasing the spatial coverage of the proxy network. The experiences gained here will be of guidance when these methods are applied to real proxy and instrumental data, for example when the aim is to distinguish which of the alternative solar forcing histories is most compatible with the observed/reconstructed climate.

  7. Munchausen syndrome by proxy and pediatric nephrology.

    Science.gov (United States)

    Bertulli, Cristina; Cochat, Pierre

    2017-11-01

    Munchausen syndrome by proxy is a persistent fabrication of illness done by a person to another. Renal and urologic forms of this syndrome are not as uncommon as can be thought; a review of all the cases of Munchausen-by-proxy syndrome reveals that 25% of the children had renal or urologic issues. This syndrome can result in a serious diagnostic dilemma for the physicians; knowing this entity can allow early recognition of falsification and limit the physical and psychological damages caused in the victim. In this study, we reviewed the pediatric nephrology cases of Munchausen syndrome by proxy, grouping them through the principal signs of presentation. Copyright © 2017 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.

  8. Toxicological evaluation of two children diagnosed as Munchausen syndrome by proxy.

    Science.gov (United States)

    Türkmen, Zeynep; Ziyalar, Neylan; Tari, Itir; Mercan, Selda; Kayiran, Sinan Mahir; Sener, Dicle; Cengiz, Salih; Akçakaya, Necla

    2012-01-01

    Munchausen syndrome by proxy is a kind of child abuse in which affected children are often hospitalized for long periods and endure repetitive, painful and expensive diagnostic attempts. We present herein two toxicologically confirmed cases of Munchausen syndrome by proxy. Case 1 is a 16-month-old male who had fever, peripheral cyanosis, tremor, and reported cardiac arrest. Symptoms recurred in the hospital when the mother administered fluids. Toxicology detected 3.5 ng/ml mercury (Hg) in the fluid and 9.4 microg Hg/g creatinine in the urine. Case 2 is a 14-year-old female who had irregular blood findings and multiple hospitalizations. Serum analysis detected warfarin. Both mothers were transferred to psychiatric care. Munchausen syndrome by proxy should be suspected when clinical/laboratory findings are negative, illness descriptions are inconsistent, and frequent hospitalization yields no diagnosis. Psychiatric evaluation and toxicological analysis are recommended.

  9. A new proxy measure for state-level gun ownership in studies of firearm injury prevention.

    Science.gov (United States)

    Siegel, Michael; Ross, Craig S; King, Charles

    2014-06-01

    Since many states are considering gun control laws, researchers need reliable data on rates of gun ownership at the state level. Survey measures of gun ownership in all 50 states, however, are only available for 3 years, and no state-level data have been collected since 2004. Consequently, the National Research Council has declared the development of a valid proxy that can be constructed from accessible, annual, state-level data to be a priority. While such a proxy does exist (the proportion of suicides in a state committed using a gun (FS/S), its correlation with state estimates of gun ownership in recent years is only 0.80. Using state-level data for the years 2001, 2002 and 2004, we developed an improved proxy for state-level gun ownership that uses FS/S (firearm suicides divided by all suicides) and also the per capita number of hunting licenses. We validated this measure using data from surveys of gun ownership conducted in 48 states during 1996 and 1999, and in 21 states during 1995-1998. Adding per capita hunting licenses to the proxy increased its correlation with survey-measured gun ownership from 0.80 to 0.95. The correlations of the new proxy with gun ownership in the two validation studies were 0.95 and 0.97. We conclude that the combination of FS/S and per capita hunting licenses improves substantially upon FS/S alone. This new proxy is easily computed from data that are available annually by state and may be useful for investigating the effect of gun prevalence on firearm-related morbidity and mortality. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  10. Quantifying the magnitude of environmental exposure misclassification when using imprecise address proxies in public health research.

    Science.gov (United States)

    Healy, Martin A; Gilliland, Jason A

    2012-04-01

    In spatial epidemiologic and public health research it is common to use spatially aggregated units such as centroids of postal/zip codes, census tracts, dissemination areas, blocks or block groups as proxies for sample unit locations. Few studies, however, address the potential problems associated with using these units as address proxies. The purpose of this study is to quantify the magnitude of distance errors and accessibility misclassification that result from using several commonly-used address proxies in public health research. The impact of these positional discrepancies for spatial epidemiology is illustrated by examining misclassification of accessibility to several health-related facilities, including hospitals, public recreation spaces, schools, grocery stores, and junk food retailers throughout the City of London and Middlesex County, Ontario, Canada. Positional errors are quantified by multiple neighborhood types, revealing that address proxies are most problematic when used to represent residential locations in small towns and rural areas compared to suburban and urban areas. Findings indicate that the shorter the threshold distance used to measure accessibility between subject population and health-related facility, the greater the proportion of misclassified addresses. Using address proxies based on large aggregated units such as centroids of census tracts or dissemination areas can result in very large positional discrepancies (median errors up to 343 and 2088 m in urban and rural areas, respectively), and therefore should be avoided in spatial epidemiologic research. Even smaller, commonly-used, proxies for residential address such as postal code centroids can have large positional discrepancies (median errors up to 109 and 1363 m in urban and rural areas, respectively), and are prone to misrepresenting accessibility in small towns and rural Canada; therefore, postal codes should only be used with caution in spatial epidemiologic research

  11. Evaluating the skeletal chemistry of Mytilus californianus as a temperature proxy: Effects of microenvironment and ontogeny

    Science.gov (United States)

    Ford, Heather L.; Schellenberg, Stephen A.; Becker, Bonnie J.; Deutschman, Douglas L.; Dyck, Kelsey A.; Koch, Paul L.

    2010-01-01

    Molluscan shell chemistry may provide an important archive of mean annual temperature (MAT) and mean annual range in temperature (MART), but such direct temperature interpretations may be confounded by biologic, metabolic, or kinetic factors. To explore this potential archive, we outplanted variously sized specimens of the common mussel Mytilus californianus at relatively low and high intertidal positions in San Diego, California, for 382 days with in situ recording of ambient temperature and periodic sampling of water chemistry. The prismatic calcite layer of eight variously sized specimens from each intertidal position were then serially microsampled and geochemically analyzed. Average intraspecimen δ18O values significantly covaried only with temperature, whereas Mg/Ca values showed a strong and significant positive correlation with growth rate. To assess intra-annual variations in shell chemistry as proxy for MART, each specimen's δ18O record was ordinated in the time domain and compared to the predicted isotopic equilibrium δ18O values from environmental data. Observed specimen values were significantly correlated with predicted equilibrium values, but show 18O enrichments of 0.2 to 0.5‰. In contrast, Mg/Ca values were poorly correlated with temperature due to significant positive relationships with growth rate and intertidal position. Within the extrapallial fluid, pH, carbonate solution chemistry, Rayleigh fractionation and/or an undetermined source of disequilibrium may cause δ18O values to deviate from predicted equilibrium precipitation for ambient seawater. Despite this consistent 18O enrichment, intraskeletal variations in δ18O values readily characterize the instrumental MAT and 5-95% MART values, making M. californianus a valuable source of information for paleoceanographic reconstructions.

  12. Reality show: um paradoxo nietzschiano

    Directory of Open Access Journals (Sweden)

    Ilana Feldman

    2011-01-01

    Full Text Available

    O fenômeno dos reality shows - e a subseqüente relação entre imagem e verdade - assenta-se sobre uma série de paradoxos. Tais paradoxos podem ser compreendidos à luz do pensamento do filósofo alemão Friedrich Nietzsche, que, através dos usos de formulações paradoxais, concebia a realidade como um mundo de pura aparência e a verdade como um acréscimo ficcional, como um efeito. A ficção é então tomada, na filosofia de Nietzsche, não em seu aspecto falsificante e desrealizador - como sempre pleiteou nossa tradição metafísica -, mas como condição necessária para que certa espécie de invenção possa operar como verdade. Sendo assim, a própria expressão reality show, através de sua formulação paradoxal, engendra explicitamente um mundo de pura aparência, em que a verdade, a parte reality da proposição, é da ordem do suplemento, daquilo que se acrescenta ficcionalmente - como um adjetivo - a show. O ornamento, nesse caso, passa a ocupar o lugar central, apontando para o efeito produzido: o efeito-de-verdade. Seguindo, então, o pensamento nietzschiano e sua atualização na contemporaneidade, investigaremos de que forma os televisivos “shows de realidade” operam paradoxalmente, em consonância com nossas paradoxais práticas culturais.

  13. Source-specific diatom lipid biomarkers as proxies for Arctic and Antarctic sea ice

    Science.gov (United States)

    Belt, Simon

    2016-04-01

    Sea ice plays a key role in controlling global climate due its influence over heat and gas exchange between the oceans and the atmosphere. In addition, sea ice exerts a strong influence over the absorption of incoming radiation at the ocean surface as a result of its high reflectivity or albedo. Driven, in part, by the recent dramatic changes to sea ice cover in both the Arctic and the Antarctic, the development of proxies for sea ice has received growing attention over the last 10 years or so. Amongst these, some so-called highly branched isoprenoid (HBI) lipid biomarkers have attracted considerable interest, not least, because they are derived from certain diatoms that reside and bloom within the sea ice matrix itself, thus providing a more direct indication of sea ice presence compared with some other proxies. The signature HBI sea proxies are a mono-unsaturated HBI (IP25) for the Arctic and a di-unsaturated HBI (C25:2) for the Antarctic, with different source organisms for each. Although the variability in sedimentary abundances of IP25 and C25:2 in Arctic and Antarctic sediments generally reflect the corresponding changes in sea ice conditions, a more complete picture of reconstructing sea ice conditions likely requires a multi-proxy approach involving, for example, other lipid biomarkers that serve as proxy measures of nearby open water conditions or sea surface temperature. By adoption of such an approach, a research strategy aimed at improving estimates of sea ice concentrations or better definitions of sea ice conditions (e.g. marginal ice zone, polynyas, permanent ice cover) represents the next stage in lipid-based sea ice proxy development. This presentation will focus on recent developments and future plans that involve a multi-proxy approach to improving sea ice reconstruction. An understanding of sources, ecology and environmental fate of various HBIs and other diatom lipids will likely be key in shaping the future direction of lipid-based sea ice

  14. Comparing proxy and model estimates of hydroclimate variability and change over the Common Era

    Science.gov (United States)

    Hydro2k Consortium, Pages

    2017-12-01

    Water availability is fundamental to societies and ecosystems, but our understanding of variations in hydroclimate (including extreme events, flooding, and decadal periods of drought) is limited because of a paucity of modern instrumental observations that are distributed unevenly across the globe and only span parts of the 20th and 21st centuries. Such data coverage is insufficient for characterizing hydroclimate and its associated dynamics because of its multidecadal to centennial variability and highly regionalized spatial signature. High-resolution (seasonal to decadal) hydroclimatic proxies that span all or parts of the Common Era (CE) and paleoclimate simulations from climate models are therefore important tools for augmenting our understanding of hydroclimate variability. In particular, the comparison of the two sources of information is critical for addressing the uncertainties and limitations of both while enriching each of their interpretations. We review the principal proxy data available for hydroclimatic reconstructions over the CE and highlight the contemporary understanding of how these proxies are interpreted as hydroclimate indicators. We also review the available last-millennium simulations from fully coupled climate models and discuss several outstanding challenges associated with simulating hydroclimate variability and change over the CE. A specific review of simulated hydroclimatic changes forced by volcanic events is provided, as is a discussion of expected improvements in estimated radiative forcings, models, and their implementation in the future. Our review of hydroclimatic proxies and last-millennium model simulations is used as the basis for articulating a variety of considerations and best practices for how to perform proxy-model comparisons of CE hydroclimate. This discussion provides a framework for how best to evaluate hydroclimate variability and its associated dynamics using these comparisons and how they can better inform

  15. A Case Report of Munchausen Syndrome by Proxy Presenting as Acquired Symptomatic West Syndrome

    Directory of Open Access Journals (Sweden)

    Shridhar Jadhav

    2016-07-01

    Full Text Available Munchausen Syndrome By Proxy (MSBP is an extremely complicated diagnosis because of the difficulty in finding the incriminating evidence of its existence and because of the ethical issue it raises for caregivers. Its implications from a medical, psychological and legal point of view raise difficult questions for any professional confronted to it. We present a case of 8 month female infant who was diagnosed to have Hyperinsulinism causing hypoglycemic brain injury and later developing intractable convulsion with head drops, where EEG was suggestive of West Syndrome, was actually a case of Munchausen syndrome by proxy to start with.

  16. Method of Anti-Virus Protection Based on (n, t Threshold Proxy Signature with an Arbitrator

    Directory of Open Access Journals (Sweden)

    E. A. Tolyupa

    2014-01-01

    Full Text Available The article suggests the method of anti-virus protection of mobile devices based on the usage of proxy digital signatures and an (n;t-threshold proxy signature scheme with an arbitrator. The unique feature of the suggested method is in the absence of necessity to install anti-virus software in a mobile device. It will be enough only to have the software verifying digital signatures and the Internet. The method is used on the base of public keys infrastructure /PKI/, thus minimizing implementation expenses.

  17. Forgery attack on one-time proxy signature and the improvement

    Science.gov (United States)

    Yang, Chun-Wei; Luo, Yi-Ping; Hwang, Tzonelih

    2014-09-01

    This paper points out that in Wang and Wei's scheme (Quantum Inf Process 11:455-463, 2012), an eavesdropper, Eve, can replace the original message of a proxy signature with a forged one of her choice without being detected by the verifier. Accordingly, one of the security requirements of a quantum signature, i.e., unforgeability, may not be satisfied in their scheme. An improvement is given to avoid this attack, and the comparisons with the existing quantum proxy signature are also demonstrated.

  18. An inter-bank E-payment protocol based on quantum proxy blind signature

    Science.gov (United States)

    Wen, Xiaojun; Chen, Yongzhi; Fang, Junbin

    2013-01-01

    Security and anonymity are essential to E-payment systems. However, with the increasing computing power, existing E-payment systems will gradually become insecure. In this paper, we propose an inter-bank E-payment system which is based on quantum proxy blind signature. Adopting the techniques of quantum key distribution, one-time pad and quantum proxy blind signature, our quantum E-payment system could protect user's anonymity as the traditional E-payment systems do, and also have unconditional security which the classical E-payment systems cannot provide. Furthermore, compared with the existing quantum E-payment systems, the proposed system could support inter-bank transactions.

  19. An E-payment Protocol Based on Quantum Multi-proxy Blind Signature

    Science.gov (United States)

    Shao, Ai-Xia; Zhang, Jian-Zhong; Xie, Shu-Cui

    2017-04-01

    Based on quantum multi-proxy blind signature, a new E-payment protocol is proposed in this paper. Adopting the techniques of quantum key distribution, one-time pad and quantum proxy blind signature, our E-payment protocol could protect user's anonymity as the traditional E-payment systems do, and also have unconditional security which the classical E-payment systems cannot provide. Additionally, the quantum operation can be transmitted successfully with the probability 1, which can make the protocol reliable and practical.

  20. Plant-derived terpenoids as paleovegetation proxies: evaluation of the proxy with Paleocene and Eocene megafloras and plant biomarkers in the Bighorn Basin, USA

    Science.gov (United States)

    Diefendorf, A. F.; Freeman, K. H.; Wing, S. L.

    2012-12-01

    Plant terpenoids (defense compounds synthesized from the 5-carbon building block isoprene) have a long history of use as geochemical plant biomarkers, and potentially can be used to reconstruct changes in the abundances of major land plant groups in rocks and sediments that do not preserve plant megafossils or pollen. Pentacyclic triterpenoids are synthesized almost exclusively by angiosperms whereas conifers produce the tricyclic diterpenoids. Many previous studies have focused on the use of di- to triterpenoid ratios to reconstruct floral changes in the geologic past, however few studies have compared terpenoid-based paleoflora proxies to pollen or megafossils. Prior reconstructions also did not take into account differences in biomarker production between plant functional types, such as deciduous and evergreen plants, which can be quite large. To investigate the use of terpenoids as paleoflora proxies, we examined sediments from the Bighorn Basin (Wyoming, USA) where ancient megafloras have been studied in detail. We analyzed di- and triterpenoid abundances as well as plant leaf waxes (n-alkanes) and other biomarkers in a total of 75 samples from 15 stratigraphic horizons from the late Paleocene (62 Ma) to early Eocene (52.5 Ma). By comparing terpenoid ratios with abundances estimated from plant megafossils, we can evaluate the utility of terpenoids as paleovegetation proxies. In nearly all samples, angiosperm triterpenoids are significantly lower in abundance than conifer diterpenoids. This contrasts with leaf fossil data that indicate paleofloras were dominated by angiosperms in both abundance and diversity. Traditional use of terpenoid paleovegetation proxies would therefore significantly overestimate the abundance of conifers, even when accounting for plant production differences. To determine if this overestimate is related to the loss of angiosperm triterpenoids (rather than enhanced production of diterpenoids in the geologic past), we compared angiosperm

  1. Inferring the Presence of Reverse Proxies Through Timing Analysis

    Science.gov (United States)

    2015-06-01

    been devoted to source authentication in a variety of fields such as anthropology , law, retail, and computer science. While no single, foolproof...Algorithm 2 to help clarify the method used to test every permutation of our PlanetLab set. Figure 3.3 shows a visual representation and description of

  2. Temperature variations in the southern Great Lakes during the last deglaciation: Comparison between pollen and GDGT proxies

    Science.gov (United States)

    Watson, Benjamin I.; Williams, John W.; Russell, James M.; Jackson, Stephen T.; Shane, Linda; Lowell, Thomas V.

    2018-02-01

    Our understanding of deglacial climate history in the southern Great Lakes region of the United States is primarily based upon fossil pollen data, with few independent and multi-proxy climate reconstructions. Here we introduce a new, well-dated fossil pollen record from Stotzel-Leis, OH, and a new deglacial temperature record based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) at Silver Lake, OH. We compare these new data to previously published records and to a regional stack of pollen-based temperature reconstructions from Stotzel-Leis, Silver Lake, and three other well-dated sites. The new and previously published pollen records at Stotzel-Leis are similar, but our new age model brings vegetation events into closer alignment with known climatic events such as the Younger Dryas (YD). brGDGT-inferred temperatures correlate strongly with pollen-based regional temperature reconstructions, with the strongest correlation obtained for a global soil-based brGDGT calibration (r2 = 0.88), lending confidence to the deglacial reconstructions and the use of brGDGT and regional pollen stacks as paleotemperature proxies in eastern North America. However, individual pollen records show large differences in timing, rates, and amplitudes of inferred temperature change, indicating caution with paleoclimatic inferences based on single-site pollen records. From 16.0 to 10.0ka, both proxies indicate that regional temperatures rose by ∼10 °C, roughly double the ∼5 °C estimates for the Northern Hemisphere reported in prior syntheses. Change-point analysis of the pollen stack shows accelerated warming at 14.0 ± 1.2ka, cooling at 12.6 ± 0.4ka, and warming from 11.6 ± 0.5ka into the Holocene. The timing of Bølling-Allerød (B-A) warming and YD onset in our records lag by ∼300-500 years those reported in syntheses of temperature records from the northern mid-latitudes. This discrepancy is too large to be attributed to uncertainties in radiocarbon dating, and

  3. Molecular proxies for climate maladaptation in a long-lived tree (Pinus pinaster Aiton, Pinaceae).

    Science.gov (United States)

    Jaramillo-Correa, Juan-Pablo; Rodríguez-Quilón, Isabel; Grivet, Delphine; Lepoittevin, Camille; Sebastiani, Federico; Heuertz, Myriam; Garnier-Géré, Pauline H; Alía, Ricardo; Plomion, Christophe; Vendramin, Giovanni G; González-Martínez, Santiago C

    2015-03-01

    Understanding adaptive genetic responses to climate change is a main challenge for preserving biological diversity. Successful predictive models for climate-driven range shifts of species depend on the integration of information on adaptation, including that derived from genomic studies. Long-lived forest trees can experience substantial environmental change across generations, which results in a much more prominent adaptation lag than in annual species. Here, we show that candidate-gene SNPs (single nucleotide polymorphisms) can be used as predictors of maladaptation to climate in maritime pine (Pinus pinaster Aiton), an outcrossing long-lived keystone tree. A set of 18 SNPs potentially associated with climate, 5 of them involving amino acid-changing variants, were retained after performing logistic regression, latent factor mixed models, and Bayesian analyses of SNP-climate correlations. These relationships identified temperature as an important adaptive driver in maritime pine and highlighted that selective forces are operating differentially in geographically discrete gene pools. The frequency of the locally advantageous alleles at these selected loci was strongly correlated with survival in a common garden under extreme (hot and dry) climate conditions, which suggests that candidate-gene SNPs can be used to forecast the likely destiny of natural forest ecosystems under climate change scenarios. Differential levels of forest decline are anticipated for distinct maritime pine gene pools. Geographically defined molecular proxies for climate adaptation will thus critically enhance the predictive power of range-shift models and help establish mitigation measures for long-lived keystone forest trees in the face of impending climate change. Copyright © 2015 by the Genetics Society of America.

  4. Limitations of remotely sensed aerosol as a spatial proxy for fine particulate matter.

    Science.gov (United States)

    Paciorek, Christopher J; Liu, Yang

    2009-06-01

    Recent research highlights the promise of remotely sensed aerosol optical depth (AOD) as a proxy for ground-level particulate matter with aerodynamic diameter pollution exposure for public health purposes. Given the correlations reported between AOD and PM(2.5), it is tempting to interpret the spatial patterns in AOD as reflecting patterns in PM(2.5). We evaluated the degree to which AOD can help predict long-term average PM(2.5) concentrations for use in chronic health studies. We calculated correlations of AOD and PM(2.5) at various temporal aggregations in the eastern United States in 2004 and used statistical models to assess the relationship between AOD and PM(2.5) and the potential for improving predictions of PM(2.5) in a subregion, the mid-Atlantic. We found only limited spatial associations of AOD from three satellite retrievals with daily and yearly PM(2.5). The statistical modeling shows that monthly average AOD poorly reflects spatial patterns in PM(2.5) because of systematic, spatially correlated discrepancies between AOD and PM(2.5). Furthermore, when we included AOD as a predictor of monthly PM(2.5) in a statistical prediction model, AOD provided little additional information in a model that already accounts for land use, emission sources, meteorology, and regional variability. These results suggest caution in using spatial variation in currently available AOD to stand in for spatial variation in ground-level PM(2.5) in epidemiologic analyses and indicate that when PM(2.5) monitoring is available, careful statistical modeling outperforms the use of AOD.

  5. Medical Child Abuse (Munchausen Syndrome by Proxy): Multidisciplinary Approach from a Pediatric Gastroenterology Perspective.

    Science.gov (United States)

    Ali-Panzarella, Andrea Z; Bryant, Tamika J; Marcovitch, Hannah; Lewis, Jeffery D

    2017-04-01

    We highlight the need for a multidisciplinary approach to the diagnosis of medical child abuse, also known as factitious disorder imposed on another (FDIA) or Munchausen syndrome by proxy (MSP), and review our experience focusing on the variety of symptoms that often present to the pediatric gastroenterologist many months before the diagnosis is made. Recent literature on medical child abuse, mostly case reports, is markedly limited, highlighting a need for increased research on this topic. Articles agree on the value of a multidisciplinary approach to these cases and the importance of involving professionals outside the hospital setting. Given the technology-dependent nature of our current society, the use of social media to aid in making the diagnosis has emerged. Review of the literature shows that there are almost no data on long-term outcomes of the victims or perpetrators of MSP. Making the diagnosis of MSP involves a complicated process of piecing together inconsistencies among the history, examination, and clinical presentation. The diagnosis remains difficult and is not often considered during early presentation of symptoms. Once MSP is suspected, it is important that a multidisciplinary process is used, incorporating input from various sources: the outpatient care structure, the hospital, non-hospital agencies such as school and child protective services, and non-traditional sources such as social media. In our experience, a multidisciplinary approach augmented by thoughtful inpatient surveillance provides the greatest opportunity for confirming or excluding MSP. Pediatric gastroenterology is one of the most common services consulted prior to diagnosis and presents an opportunity for early intervention.

  6. Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and Other Meteorological Measurements

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawrence D.; Cecil, Daniel J.; Bateman, Monte

    2012-01-01

    The lightning jump algorithm has a robust history in correlating upward trends in lightning to severe and hazardous weather occurrence. The algorithm uses the correlation between the physical principles that govern an updraft's ability to produce microphysical and kinematic conditions conducive for electrification and its role in the development of severe weather conditions. Recent work has demonstrated that the lightning jump algorithm concept holds significant promise in the operational realm, aiding in the identification of thunderstorms that have potential to produce severe or hazardous weather. However, a large amount of work still needs to be completed in spite of these positive results. The total lightning jump algorithm is not a stand-alone concept that can be used independent of other meteorological measurements, parameters, and techniques. For example, the algorithm is highly dependent upon thunderstorm tracking to build lightning histories on convective cells. Current tracking methods show that thunderstorm cell tracking is most reliable and cell histories are most accurate when radar information is incorporated with lightning data. In the absence of radar data, the cell tracking is a bit less reliable but the value added by the lightning information is much greater. For optimal application, the algorithm should be integrated with other measurements that assess storm scale properties (e.g., satellite, radar). Therefore, the recent focus of this research effort has been assessing the lightning jump's relation to thunderstorm tracking, meteorological parameters, and its potential uses in operational meteorology. Furthermore, the algorithm must be tailored for the optically-based GOES-R Geostationary Lightning Mapper (GLM), as what has been observed using Very High Frequency Lightning Mapping Array (VHF LMA) measurements will not exactly translate to what will be observed by GLM due to resolution and other instrument differences. Herein, we present some of

  7. Magntic susceptibility as a proxy to heavy metal content in the sediments of Anzali wetland, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Vesali Naseh

    2012-12-01

    Full Text Available Heavy metal concentrations and magnetic susceptibility of sediment samples were analyzed as indicators of urban and industrial contamination in Anzali wetland in Gilan, Iran. The aim was to investigate the suitability of magnetic properties measurements for indicating heavy metal pollution. The concentration of six heavy metals (Ni, Cr, Cd, Zn,Fe, and Pb was determined in different depths of four sediment core samples within four different regions of thewetland (Abkenar, Hendekhaleh, Shijan and Siakeshim. Average concentration of heavy metals in the sediment cores was higher than the severe effect level (SEL for Ni, Cr and Fe (77.26, 113.63 ppm and 5.2%, respectively and lower than SEL for Cd, Zn and Pb (0.84, 137.7, 29.77 ppm, respectively. It was found that the trend of metalconcentrations with the depth is different in each core and is related to the pollution discharges into the rivers entering the wetland. Core magnetic susceptibility measurements also showed different magnetic properties in each core. Cluster analysis was applied using Pearson correlation coefficient between heavy metal concentrations and magnetic properties across each core. Significant relationship was found to exist between magnetic susceptibility and the concentration of Ni in Abkenar and the concentration of Fe in other regions. Whereas Abkenar is almost the isolated and uncontaminated region of the wetland, it revealed a difference in magnetic properties between contaminated and uncontaminated sediments. It was concluded that magnetic properties ofsamples from contaminated zone were mostly related to Fe content. The result of this study demonstrated that magnetic susceptibility measurements could be applied as a proxy method for heavy metal pollution determination in marine environments in Iran especially as a rapid and cost-effective introductory site assessments.

  8. Magntic susceptibility as a proxy to heavy metal content in the sediments of Anzali wetland, Iran

    Directory of Open Access Journals (Sweden)

    Naseh Mohammad Reza Vesali

    2012-12-01

    Full Text Available Abstract Heavy metal concentrations and magnetic susceptibility of sediment samples were analyzed as indicators of urban and industrial contamination in Anzali wetland in Gilan, Iran. The aim was to investigate the suitability of magnetic properties measurements for indicating heavy metal pollution. The concentration of six heavy metals (Ni, Cr, Cd, Zn, Fe, and Pb was determined in different depths of four sediment core samples within four different regions of the wetland (Abkenar, Hendekhaleh, Shijan and Siakeshim. Average concentration of heavy metals in the sediment cores was higher than the severe effect level (SEL for Ni, Cr and Fe (77.26, 113.63 ppm and 5.2%, respectively and lower than SEL for Cd, Zn and Pb (0.84, 137.7, 29.77 ppm, respectively. It was found that the trend of metal concentrations with the depth is different in each core and is related to the pollution discharges into the rivers entering the wetland. Core magnetic susceptibility measurements also showed different magnetic properties in each core. Cluster analysis was applied using Pearson correlation coefficient between heavy metal concentrations and magnetic properties across each core. Significant relationship was found to exist between magnetic susceptibility and the concentration of Ni in Abkenar and the concentration of Fe in other regions. Whereas Abkenar is almost the isolated and uncontaminated region of the wetland, it revealed a difference in magnetic properties between contaminated and uncontaminated sediments. It was concluded that magnetic properties of samples from contaminated zone were mostly related to Fe content. The result of this study demonstrated that magnetic susceptibility measurements could be applied as a proxy method for heavy metal pollution determination in marine environments in Iran especially as a rapid and cost-effective introductory site assessments.

  9. 'Doing good by proxy': human-animal kinship and the 'donation' of canine blood.

    Science.gov (United States)

    Ashall, Vanessa; Hobson-West, Pru

    2017-07-01

    This article demonstrates the relevance of animals to medical sociology by arguing that pet owners' accounts of veterinary decision-making can highlight key sociological themes which are important to both human and animal health. Based on semi-structured interviews, the article argues that interspecies 'kinship' allows for the extension of sociological claims regarding altruism, self-interest and mutuality from human blood donation to companion animal blood 'donation'. Furthermore, this study extends sociological understanding of the human-animal bond by showing how the dog's status as kin meant they were expected to donate blood, and that the act of donation itself represents an important opportunity for family 'display'. However, owners who do not or cannot donate blood themselves describe pet blood donation as an opportunity to lessen associated feelings of guilt or obligation through 'doing good by proxy'. These findings raise critical sociological and ethical questions concerning the risks and benefits of donation, and for how we understand third-party decision making. Finally, the article argues for the close entanglement of human and animal health, and concludes that sociologists of health and medicine should explore the radical possibility that decision-making in healthcare more generally might be influenced by experiences at the veterinary clinic, and vice versa. (A Virtual Abstract of this paper can be viewed at: https://www.youtube.com/channel/UC_979cmCmR9rLrKuD7z0ycA). © 2017 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for SHIL.

  10. Explosion swarms at Stromboli volcano: A proxy for nonequilibrium conditions in the shallow plumbing system

    Science.gov (United States)

    de Martino, S.; Errico, A.; Palo, M.; Cimini, G. B.

    2012-03-01

    In this paper we look at changes of the statistics of the stationary explosive process at a basaltic volcano as a proxy for departures from thermodynamic equilibrium conditions in the shallow plumbing system. Specifically, we investigate the explosion process of Stromboli volcano that occurred during 2002-2003, 2006-2007 and 2010-2011. The first two periods were characterized by eruptions with significant lava effusion and strong paroxysmal events, while the last one shows persistent explosive activity accompanied by minor episodes of lava flow. We use three-component seismic data recorded by broadband stations operating on the volcano and, for 2007 and 2010-2011 cases, strainmeter data from a Sacks-Evertson borehole dilatometer. For each time interval we study the explosive process by looking at the inter-occurrence times and at the amplitude distribution. Moreover, we analyze its waveforms, spectral content and polarization properties. In all three cases we find sharp increases of the explosion rate associated with swarms. Swarms are characterized by quasi-monochromatic seismic events with frequency peak close to about 3 Hz, higher amplitude than the usual explosions and variability coefficient of the inter-occurrence times close to 0.5. In correspondence to the swarms, we also observe negative variations in the strain signals, which indicate a depressurization in the shallow plumbing system. This depressurization emerges clearly from the data collected during 2010-2011, whereas it is less sharp for the 2007 episode, and has been estimated in about 105 Pa. From the polarization analysis we infer that this depressurization affects the upper 0.3-0.8 km of the plumbing system.

  11. Photodegradation mechanism of sulfonamides with excited triplet state dissolved organic matter: A case of sulfadiazine with 4-carboxybenzophenone as a proxy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingjie; Wei, Xiaoxuan; Chen, Jingwen, E-mail: jwchen@dlut.edu.cn; Xie, Hongbin; Zhang, Ya-nan

    2015-06-15

    Highlights: • Excited triplet state of dissolved organic matter ({sup 3}DOM{sup *}) is largely responsible for the enhanced photodegradation of sulfadiazine. • Electron followed by proton transfer is a major mechanism for the reactions of sulfadiazine with {sup 3}DOM{sup *} proxies. • Two reaction sites (amino- or sulfonyl-N) and sulfadiazine radicals were identified in the reactions of sulfadiazine with {sup 3}DOM{sup *} proxies. - Abstract: Excited triplet states of dissolved organic matter ({sup 3}DOM*) are important players for photodegradation sulfonamide antibiotics (SAs) in sunlit natural waters. However, the triplet-mediated reaction mechanism was poorly understood. In this study, we investigated the reaction adopting sulfadiazine as a representative SA and 4-carboxybenzophenone (CBBP)as a proxy of DOM. Results showed that the excited triplet state of CBBP ({sup 3}CBBP*) is responsible for the photodegradation of sulfadiazine. The reaction of {sup 3}CBBP* with substructure model compounds verified there are two reaction sites (amino-or sulfonyl-N atoms) of sulfadiazine. Density functional theory calculations were performed, which unveiled that electrons transfer from the N reaction sites to the carbonyl oxygen atom of {sup 3}CBBP* moiety, followed by proton transfers, leading to the formation of sulfadiazine radicals. Laser flash photolysis experiments were performed to confirm the mechanism. Thus, this study identified that the photodegradation mechanism of SAs initiated by {sup 3}DOM*, which is important for understanding the photochemical fate, predicting the photoproducts, and assessing the ecological risks of SAs in the aquatic environment.

  12. The level of agreement between child self-reports and parent proxy-reports of health-related quality of life in boys with Duchenne muscular dystrophy.

    Science.gov (United States)

    Lim, Yoonjeong; Velozo, Craig; Bendixen, Roxanna M

    2014-09-01

    To investigate the level of agreement between child self-reports and parent proxy-reports of the health-related quality of life (HRQoL) in boys with Duchenne muscular dystrophy (DMD) using both classical test theory (CTT) and Rasch analysis. A total of 63 boys with DMD and their parents completed the pediatric quality of life inventory version 4.0 child self-report and parent proxy-report of HRQoL, respectively. The data were analyzed using both the CTT (scale-score level) and Rasch analysis (item-level). The intraclass correlation coefficient (ICC, scale-score level) between children and parents showed good to moderate agreement, although parents consistently underestimated their child HRQoL. In Rasch analysis (item-level), 1 out of 8 items was significantly different between children and parents in the physical health scale. Also, 3 out of 15 items were significantly different between those two groups in the psychosocial health scale. By applying both scale-score and item-level analyses, our study seeks to broaden the understanding of the discrepancy of the ratings between child self-reports and parent proxy-reports. The findings could provide further information about the decision-making process when selecting therapy and care programs.

  13. Testing the potential of bacterial branched tetraether membrane lipids as temperature proxy in peat and immature coal deposits

    Science.gov (United States)

    Weijers, J. W. H.; Steinmann, P.; Hopmans, E. C.; Basiliko, N.; Finkelstein, S. A.; Johnson, K. R.; Schouten, S.; Sinninghe Damsté, J. S.

    2012-04-01

    Branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids occur ubiquitously in peat and soil. In soil, the degree of methylation and cyclisation of branched tetraethers (MBT index and CBT ratio, respectively) has shown to relate to both soil pH and annual mean air temperature (MAT). Using this relation, past annual MATs can be reconstructed by analysing brGDGTs in marine sediment records near large river outflows. More recently, the potential of this MBT/CBT proxy is also being explored in lakes. Despite being more abundant in peat than soils, however, the utility of the proxy has not yet been fully explored in peat records. Present day peat records generally extent back to the early Holocene, but if the MBT/CBT proxy were shown to be applicable in peat deposits, there is also potential to apply it to immature coal deposits like lignites, which could provide valuable snapshots of continental climate back to the early Cenozoic. Here results are presented of analyses of different peats in south eastern Canada, showing that the pH of peat along a nutrient gradient is rather well reflected by the CBT. Annual MAT reconstructions based on the MBT/CBT soil calibration, however, tend to overestimate measured MAT. This is also the case for peat analysed from the surface of Etang de la Gruère peat bog in the Swiss Jura Mountains. Along the 6m depth profile of this bog (~13ka), CBT-reconstructed pH is compared with in-situ measured pore water pH showing that the brGDGT composition does not reflect present-day in-situ conditions. Instead, it reflects a stratigraphic boundary between Carex and Sphagnum dominated peat at 4 m depth that is not present in the pore water profile, testifying to a 'fossil' nature of the brGDGTs down the peat bog. Analyses of three immature coals of the Argonne Premium Coal Series reveal that branched GDGTs are present in the most immature coal, the Beulah Zap lignite (Ro = 0.25%), and only just above detection limit in the Wyodak

  14. A high-resolution multi-proxy record of late Cenozoic environment change from central Taklimakan Desert, China

    Science.gov (United States)

    Wang, X.; Sun, D. H.; Wang, F.; Li, B. F.; Wu, S.; Guo, F.; Li, Z. J.; Zhang, Y. B.; Chen, F. H.

    2013-12-01

    The Taklimakan Desert in the Tarim Basin is the largest desert in Central Asia, and is regarded as one of the main dust sources to the Northern Hemisphere. Late Cenozoic sedimentary sequences with intercalated in-situ aeolian dune sands in this area preserve direct evidence for the Asian desertification. Herein, we report a high-resolution multi-proxy climatic record from the precise magnetostratigraphic dated Hongbaishan section in the central Taklimakan Desert. Our results show that a fundamental climate change, characterised by significant cooling, enhanced aridity, and intensified atmospheric circulation, occurred at 2.8 Ma. Good correlations between paleo-environmental records in the dust sources and downwind areas suggest a broadly consistent climate evolution of northwestern China during the late Cenozoic, which is probably driven by the uplift of the Tibet Plateau and the Northern Hemisphere glaciation.

  15. Intrareef variations in Li/Mg and Sr/Ca sea surface temperature proxies in the Caribbean reef-building coral Siderastrea siderea

    Science.gov (United States)

    Fowell, Sara E.; Sandford, Kate; Stewart, Joseph A.; Castillo, Karl D.; Ries, Justin B.; Foster, Gavin L.

    2016-10-01

    Caribbean sea surface temperatures (SSTs) have increased at a rate of 0.2°C per decade since 1971, a rate double that of the mean global change. Recent investigations of the coral Siderastrea siderea on the Belize Mesoamerican Barrier Reef System (MBRS) have demonstrated that warming over the last 30 years has had a detrimental impact on calcification. Instrumental temperature records in this region are sparse, making it necessary to reconstruct longer SST records indirectly through geochemical temperature proxies. Here we investigate the skeletal Sr/Ca and Li/Mg ratios of S. siderea from two distinct reef zones (forereef and backreef) of the MBRS. Our field calibrations of S. siderea show that Li/Mg and Sr/Ca ratios are well correlated with temperature, although both ratios are 3 times more sensitive to temperature change in the forereef than in the backreef. These differences suggest that a secondary parameter also influences these SST proxies, highlighting the importance for site- and species-specific SST calibrations. Application of these paleothermometers to downcore samples reveals highly uncertain reconstructed temperatures in backreef coral, but well-matched reconstructed temperatures in forereef coral, both between Sr/Ca-SSTs and Li/Mg-SSTs, and in comparison to the Hadley Centre Sea Ice and Sea Surface Temperature record. Reconstructions generated from a combined Sr/Ca and Li/Mg multiproxy calibration improve the precision of these SST reconstructions. This result confirms that there are circumstances in which both Li/Mg and Sr/Ca are reliable as stand-alone and combined proxies of sea surface temperature. However, the results also highlight that high-precision, site-specific calibrations remain critical for reconstructing accurate SSTs from coral-based elemental proxies.

  16. Comparison of multi-proxy data with past1000 model output over the Terminal Classic Period (800-1000 A.D.) on the Yucatan Peninsula.

    Science.gov (United States)

    Van Pelt, S.; Kohfeld, K. E.; Allen, D. M.

    2015-12-01

    The decline of the Mayan Civilization is thought to be caused by a series of droughts that affected the Yucatan Peninsula during the Terminal Classic Period (T.C.P.) 800-1000 AD. The goals of this study are two-fold: (a) to compare paleo-model simulations of the past 1000 years with a compilation of multiple proxies of changes in moisture conditions for the Yucatan Peninsula during the T.C.P. and (b) to use this comparison to inform the modeling of groundwater recharge in this region, with a focus on generating the daily climate data series needed as input to a groundwater recharge model. To achieve the first objective, we compiled a dataset of 5 proxies from seven locations across the Yucatan Peninsula, to be compared with temperature and precipitation output from the Community Climate System Model Version 4 (CCSM4), which is part of the Coupled Model Intercomparison Project Phase 5 (CMIP5) past1000 experiment. The proxy dataset includes oxygen isotopes from speleothems and gastropod/ostrocod shells (11 records); and sediment density, mineralogy, and magnetic susceptibility records from lake sediment cores (3 records). The proxy dataset is supplemented by a compilation of reconstructed temperatures using pollen and tree ring records for North America (archived in the PAGES2k global network data). Our preliminary analysis suggests that many of these datasets show evidence of drier and warmer climate on the Yucatan Peninsula around the T.C.P. when compared to modern conditions, although the amplitude and timing of individual warming and drying events varies between sites. This comparison with modeled output will ultimately be used to inform backward shift factors that will be input to a stochastic weather generator. These shift factors will be based on monthly changes in temperature and precipitation and applied to a modern daily climate time series for the Yucatan Peninsula to produce a daily climate time series for the T.C.P.

  17. Effects of Art Therapy on Distress Levels of Adults with Cancer: A Proxy Pretest Study

    Science.gov (United States)

    Glinzak, Leara

    2016-01-01

    This study identified decreased distress after art therapy in a proxy pretest study with a convenience sample of 73 patients being treated for cancer. Art therapy outcomes from 4 settings (oncology unit, infusion clinic, individual sessions, and open studio) were measured via the self-report Distress Thermometer, which was collected as part of an…

  18. Reducing handover latency in future IP-based wireless networks: Fast Proxy Mobile IPv6

    NARCIS (Netherlands)

    Heijenk, Geert; Bargh, Mortaza S.; Laganier, Julien; Prasad, Anand R.

    2008-01-01

    Current IP-level mobility protocols have difficulties meeting the stringent handover delay requirements of future wireless networks. At the same time they do not give sufficient control to the network to control the handover process. This paper presents an extension to Proxy Mobile IP, which is the

  19. Ethiopia-Eritrea : proxy wars and prospects of peace in the Horn of Africa

    NARCIS (Netherlands)

    Abbink, G.J.

    2003-01-01

    Many inter-State and intra-State conflicts in Africa become more complex by being extended into 'proxy wars', i.e. secondary, often 'low intensity' armed conflicts, pursued in the context of a major power struggle, or outright wars between States carried out by subsidiary or co-opted insurgent

  20. Sources and proxy potential of long chain alkyl diols in lacustrine environments.

    NARCIS (Netherlands)

    Rampen, Sebastiaan W.; Datema, Mariska; Rodrigo-Gámiz, M.; Schouten, Stefan; Reichart, Gert-Jan; Sinninghe Damste, Jaap S.

    2014-01-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD)

  1. Sources and proxy potential of long chain alkyl diols in lacustrine environments

    NARCIS (Netherlands)

    Rampen, S.; Datema, M.; Rodrigo-Gámiz, M.; Schouten, S.; Reichart, G.-J.; Sinninghe Damsté, J.S.

    2014-01-01

    Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD)

  2. Comparing children's GPS tracks with geospatial proxies for exposure to junk food.

    Science.gov (United States)

    Sadler, Richard C; Gilliland, Jason A

    2015-01-01

    Various geospatial techniques have been employed to estimate children's exposure to environmental cardiometabolic risk factors, including junk food. But many studies uncritically rely on exposure proxies which differ greatly from actual exposure. Misrepresentation of exposure by researchers could lead to poor decisions and ineffective policymaking. This study conducts a GIS-based analysis of GPS tracks--'activity spaces'--and 21 proxies for activity spaces (e.g. buffers, container approaches) for a sample of 526 children (ages 9-14) in London, Ontario, Canada. These measures are combined with a validated food environment database (including fast food and convenience stores) to create a series of junk food exposure estimates and quantify the errors resulting from use of different proxy methods. Results indicate that exposure proxies consistently underestimate exposure to junk foods by as much as 68%. This underestimation is important to policy development because children are exposed to more junk food than estimated using typical methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Deuterium values from volcanic glass: A paleoelevation proxy for Oregon's Cascade Range

    Science.gov (United States)

    Carlson, T. B.; Bershaw, J. T.

    2016-12-01

    Hydrated volcanic glass has been used as a proxy to constrain Cenozoic paleoclimate across many of the world's mountain ranges. However, there are concerns that volcanic glass may not preserve the isotopic composition of syndepositional meteoric water. The Cascades are an excellent location to study the validity of hydrated volcanic glass as a paleoenvironmental proxy for several reasons. Moisture is derived from a single oceanic source and falls as orographic precipitation in the Cascades, leading to a characteristic altitude effect, or inverse relationship between elevation and the isotopic composition of meteoric water (δD). In addition, past studies have inferred uplift of the Cascades and an increase in the rain shadow effect since the Eocene through independent methods such as changing fossil assemblages, and other isotopic proxies including carbonates and fossil teeth. In this study, δD values of two hydrated tuff samples are compared: one prior to ( 29 Ma) and one following ( 5 Ma) the onset of High Cascade volcanism. The isotopic composition of these samples are interpreted in the context of modern water across the range to understand the potential of volcanic glass as a proxy for paleoelevation in the Pacific Northwest.

  4. Constructing Proxy Variables to Measure Adult Learners' Time Management Strategies in LMS

    Science.gov (United States)

    Jo, Il-Hyun; Kim, Dongho; Yoon, Meehyun

    2015-01-01

    This study describes the process of constructing proxy variables from recorded log data within a Learning Management System (LMS), which represents adult learners' time management strategies in an online course. Based on previous research, three variables of total login time, login frequency, and regularity of login interval were selected as…

  5. Validity of proxy data obtained by different psychological autopsy information reconstruction techniques.

    Science.gov (United States)

    Fang, L; Zhang, J

    2010-01-01

    Two informants were interviewed for each of 416 living controls (individuals sampled from the normal population) interviewed in a Chinese case-control psychological autopsy study. The validity of proxy data, obtained using seven psychological autopsy information reconstruction techniques (types 1, 2 and A - E), was evaluated, with living controls' self reports used as the gold-standard. Proxy data for reconstruction technique types 1, 2 and D on the Impulsivity Inventory Scale (total impulsivity score) were no different from the living controls' self report gold standard, whereas data for types A and E were smaller than data from living controls. On the 'acceptance or resignation' sub-scale of the avoidance coping dimension of the Moos Coping Response Inventory, information obtained by reconstruction technique types 1 and D was not significantly different from the living controls' self reports, whereas proxy data from types 2, A and E were smaller than those from the living controls. No statistically significant differences were identified for other proxy data obtained by reconstruction technique types 1, 2, A, D and E. These results indicate that using a second informant does not significantly enhance information reconstruction for the target.

  6. Optical Proxies for Terrestrial Dissolved Organic Matter in Estuaries and Coastal Waters

    Directory of Open Access Journals (Sweden)

    Christopher L. Osburn

    2016-01-01

    Full Text Available Optical proxies, especially DOM fluorescence, were used to track terrestrial DOM fluxes through estuaries and coastal waters by comparing models developed for several coastal ecosystems. Key to using optical properties is validating and calibrating them with chemical measurements, such as lignin-derived phenols - a proxy to quantify terrestrial DOM. Utilizing parallel factor analysis (PARAFAC, and comparing models statistically using the OpenFluor database (http://www.openfluor.org we have found common, ubiquitous fluorescing components which correlate most strongly with lignin phenol concentrations in several estuarine and coastal environments. Optical proxies for lignin were computed for the following regions: Mackenzie River Estuary, Atchafalaya River Estuary, Charleston Harbor, Chesapeake Bay, and Neuse River Estuary. The slope of linear regression models relating CDOM absorption at 350 nm (a350 to DOC and to lignin, varied 5 to 10 fold among systems. Where seasonal observations were available from a region, there were distinct seasonal differences in equation parameters for these optical proxies. Despite variability, overall models using single linear regression were developed that related dissolved organic carbon (DOC concentration to CDOM (DOC = 40×a350+138; R2 = 0.77; N = 130 and lignin (Σ8 to CDOM (Σ8 = 2.03×a350-0.5; R2 = 0.87; N = 130. This wide variability suggested that local or regional optical models should be developed for predicting terrestrial DOM flux into coastal oceans and taken into account when upscaling to remote sensing observations and calibrations.

  7. 17 CFR 240.14a-4 - Requirements as to proxy.

    Science.gov (United States)

    2010-04-01

    ... persons making the solicitation do not know, a reasonable time before the solicitation, are to be... elected. Provided, however, That nothing in this section 240.14a-4 shall prevent any person soliciting in... authority to vote for nominees named in the registrant's proxy statement, so long as the soliciting party...

  8. Proxy documents as a source of measurement error in the Comparative Manifestos Project.

    NARCIS (Netherlands)

    Gemenis, Konstantinos

    2012-01-01

    This paper considers the issue of document type diversity in the Comparative Manifestos Project (CMP). For many years the CMP has been collecting and coding a variety of documents, such as speeches, pamphlets, newspaper articles and leaflets, as manifesto proxies. By using previously unexplored

  9. The Deceit Continues: An Updated Literature Review of Munchausen Syndrome By Proxy.

    Science.gov (United States)

    Sheridan, Mary S.

    2003-01-01

    This updated review of the literature on Munchausen Syndrome by Proxy (MBSP) analyzes 451 cases from 154 medical and psychosocial journal articles. Typical victims were usually 4 years of age or under; 6% were dead, and 7.3% suffered long-term or permanent injury. Twenty-five percent of siblings were dead. Mothers were perpetrators in 76.5% of…

  10. Characteristics of Hospital-Based Munchausen Syndrome by Proxy in Japan

    Science.gov (United States)

    Fujiwara, Takeo; Okuyama, Makiko; Kasahara, Mari; Nakamura, Ayako

    2008-01-01

    Objective: This article explores characteristics of Munchausen Syndrome by Proxy (MSBP) in Japan, a country which provides an egalitarian, low cost, and easy-access health care system. Methods: We sent a questionnaire survey to 11 leading doctors in the child abuse field in Japan, each located in different hospital-based sites. Child abuse doctors…

  11. Beyond Munchausen by Proxy: A Proposed Conceptualization for Cases of Recurring, Unsubstantiated Sexual Abuse Allegations

    Science.gov (United States)

    Lindahl, Mary W.

    2009-01-01

    In the emerging literature, cases involving recurring, unsubstantiated allegations of child sexual abuse have generally been categorized as Munchausen by proxy. Recent scholars have recommended restricting the label to the original conceptualization, involving purposeful deception motivated by psychological needs for medical attention. This leaves…

  12. Web of Deceit: A Literature Review of Munchausen Syndrome by Proxy.

    Science.gov (United States)

    Rosenberg, Donna A.

    1987-01-01

    A literature review and case study provide detailed characteristics of Munchausen syndrome by proxy, a form of child abuse wherein the mother falsifies illness in her child through simulation and/or production of illness, presenting the child for medical care while disclaiming knowledge of its etiology. Guidelines for medical, social service, and…

  13. Repeated False Allegations of Sexual Abuse Presenting to Sheriffs: When Is It Munchausen by Proxy?

    Science.gov (United States)

    Schreier, Herbert A.

    1996-01-01

    In cases of Munchausen Syndrome by Proxy, the perpetrator (generally the mother) simulates or fabricates child abuse in order to maintain an intense relationship with hospital personnel, police personnel, child protection workers, lawyers, or school personnel. A case involving law enforcement agents as a primary "target" illustrates…

  14. Munchausen by Proxy: A Case, Chart Series, and Literature Review of Older Victims

    Science.gov (United States)

    Awadallah, Nida; Vaughan, Aaron; Franco, Kathleen; Munir, Farah; Sharaby, Na'ama; Goldfarb, Johanna

    2005-01-01

    The history of an older child victim of Munchausen by proxy (MBP) is described. He was referred for evaluation after repeated sinus surgeries for recurrent sinus infections believed to be related to a falsified history of an immunodeficiency. The perpetrator was the mother of this 14-year-old victim, consistent with the majority of such cases.…

  15. Concerns about Research and Prevention Strategies in Munchausen Syndrome by Proxy (MSBP) Abuse.

    Science.gov (United States)

    Eminson, Mary; Jureidini, Jon

    2003-01-01

    This article examines three motives for research into Munchausen Syndrome by Proxy child abuse, which are to enhance treatment, to understand the psychopathology of perpetrators, and to find interventions to prevent its occurrence. It argues that only the first justification is valid and proposes that research energy be directed toward…

  16. Parent and Athlete Perceptions of Special Olympics Participation: Utility and Danger of Proxy Responding

    Science.gov (United States)

    Glidden, Laraine Masters; Bamberger, Katharine T.; Draheim, Angela R.; Kersh, Joanne

    2011-01-01

    Participation in athletics has benefits for persons with intellectual disabilities and their parents. Our purposes here were to confirm these benefits and to determine whether reports from athletes and parents were comparable (i.e., to test the validity of proxy responding). We conducted interviews with 34 Special Olympics sailing/kayaking…

  17. The effect of chemical pretreatment of sediment upon foraminiferal-based proxies

    NARCIS (Netherlands)

    Feldmeijer, W.; Metcalfe, B.; Scussolini, P.; Arthur, K.L.

    2013-01-01

    Paleoceanographic studies routinely combine different foraminiferal proxies (i.e., weight, abundance, trace metal, and stable isotope measurements) into a cohesive narrative. The application of chemical treatment to disaggregate ocean sediments in the most efficient way to isolate the fossils of

  18. Multi-proxy summer and winter precipitation reconstruction for southern Africa over the last 200 years

    NARCIS (Netherlands)

    Neukom, R.; Nash, D.J.; Endfield, G.H.; Grab, S.W; Grove, C.A.; Kelso, C.; Vogel, C.H.; Zinke, J.

    2014-01-01

    This study presents the first consolidation of palaeoclimate proxy records from multiple archives to develop statistical rainfall reconstructions for southern Africa covering the last two centuries. State-of-the-art ensemble reconstructions reveal multi-decadal rainfall variability in the summer and

  19. Phylogenetic patterns are not proxies of community assembly mechanisms (they are far better)

    NARCIS (Netherlands)

    Gerhold, Pille; Cahill, J.F.; Winter, Marten; Bartish, I.V.; Prinzing, Andreas

    2015-01-01

    The subdiscipline of 'community phylogenetics' is rapidly growing and influencing thinking regarding community assembly. In particular, phylogenetic dispersion of co-occurring species within a community is commonly used as a proxy to identify which community assembly processes may have structured

  20. Linking coral river runoff proxies with climate variability, hydrology and land-use in Madagascar catchments

    NARCIS (Netherlands)

    Maina, J.; de Moel, H.; Vermaat, J.E.; Bruggemann, J.H.; Guillaume, M.M.M.; Grove, C.A.; Madin, J.S.; Merz-Kraus, R.; Zinke, J.

    2012-01-01

    Understanding the linkages between coastal watersheds and adjacent coral reefs is expected to lead to better coral reef conservation strategies. Our study aims to examine the main predictors of environmental proxies recorded in near shore corals and therefore how linked near shore reefs are to the

  1. Fluxes, diagenesis, and the variation of proxies in eastern Mediterranean sediments

    NARCIS (Netherlands)

    Santvoort, Petrus Johannes Maria van

    2004-01-01

    In this thesis diagenetic processes in both organic-poor and organic-rich eastern Mediterranean sediments are studied. Furthermore, (present-day) fluxes and the variations in several proxies are discussed. Chapter 2 deals with the aerobic mineralisation of Corg in surface sediments of the deep

  2. Show Me My Health Plans

    Directory of Open Access Journals (Sweden)

    Mary C. Politi PhD

    2016-11-01

    Full Text Available Introduction: Since the Affordable Care Act was passed, more than 12 million individuals have enrolled in the health insurance marketplace. Without support, many struggle to make an informed plan choice that meets their health and financial needs. Methods: We designed and evaluated a decision aid, Show Me My Health Plans (SMHP, that provides education, preference assessment, and an annual out-of-pocket cost calculator with plan recommendations produced by a tailored, risk-adjusted algorithm incorporating age, gender, and health status. We evaluated whether SMHP compared to HealthCare.gov improved health insurance decision quality and the match between plan choice, needs, and preferences among 328 Missourians enrolling in the marketplace. Results: Participants who used SMHP had higher health insurance knowledge (LS-Mean = 78 vs. 62; P < 0.001, decision self-efficacy (LS-Mean = 83 vs. 75; P < 0.002, confidence in their choice (LS-Mean = 3.5 vs. 2.9; P < 0.001, and improved health insurance literacy (odds ratio = 2.52, P < 0.001 compared to participants using HealthCare.gov . Those using SMHP were 10.3 times more likely to select a silver- or gold-tier plan (P < 0.0001. Discussion: SMHP can improve health insurance decision quality and the odds that consumers select an insurance plan with coverage likely needed to meet their health needs. This study represents a unique context through which to apply principles of decision support to improve health insurance choices.

  3. The Holocene Records of Glycerol Dialkyl Glycerol Tetraethers From the Northern Chukchi Sea

    Science.gov (United States)

    Park, Y.; Yamamoto, M.; Nam, S.; Polyak, L. V.

    2013-12-01

    We analyzed glycerol dialkyl glycerol tetraethers (GDGTs) in Cores HOTRAX 05-01 JPC5 and JPC 8, and ARA02B 01-GC in the northern Chukchi Sea. All of the three cores showed a similar changing pattern in GDGT composition during the Holocene. In the beginning of early Holocene, both isoprenoid and branched GDGT concentrations were low, and BIT and CBT were relatively high. The similar composition is found in modern sediments from the western Arctic Ocean north of 75°N, suggesting that the northern Chukchi Sea was covered by perennial sea ice. GDGT concentration increased, and BIT and CBT decreased during the early Holocene and reached the same level as those in modern sediments at 8 ka. TEX86 and CBT/MBT indices showed millennial-scale variation. We interpret that these proxies did not simply indicate temperatures but were affected by the relative contribution of different sediment sources. Millennial-scale variability likely reflected changes in sediment transport in the northern Chukchi Sea.

  4. Variability in drift ice export from the Arctic Ocean to the North Icelandic Shelf over the last 8000 years: A multi-proxy evaluation

    Science.gov (United States)

    Cabedo-Sanz, Patricia; Belt, Simon T.; Jennings, Anne E.; Andrews, John T.; Geirsdóttir, Áslaug

    2016-08-01

    high SSTs. During the mid-Holocene (ca 6.2-3.3 cal ka BP), drift ice increased concomitant with decreasing SSTs, although primary productivity was somewhat enhanced during this interval. IP25 first reached its mean value for the entire record at ca 5 cal ka BP, before increasing, continuously, ca 4.3 cal ka BP, broadly in line with the onset of Neoglaciation as seen in some other proxy records. Further increases in drift ice were evident during the late Holocene (ca 3.3 cal ka BP to present), culminating in maximum sea ice during the Little Ice Age. In addition, the IP25 record from MD99-2269 shows some positive regime shifts from the general trend, especially at ca 3.8, 2.7, 1.5, 0.7 and 0.4 cal ka BP, that have analogs in some other paleoceanographic reconstructions influenced by the East Greenland Current. The abrupt increases in IP25 at ca 1.5 and 0.7 cal ka BP are coincident with rapid cooling identified previously in an Icelandic lacustrine temperature record, suggesting significant coupling between the marine and terrestrial systems. The contribution of sea ice to the broader climate system is further evidenced through the identification of statistically significant periodicities (ca 1000 yr and ca 200-230 yr) in the drift ice proxy data that have counterparts in previous studies concerning atmospheric and oceanic variability and solar forcing mechanisms.

  5. Proxy Perspectives about End-of-Life Care for Person’s with Cancer

    Science.gov (United States)

    Bakitas, Marie; Ahles, Tim A.; Skalla, Karen; Brokaw, Frances C.; Byock, Ira; Hanscom, Brett; Lyons, Kathleen Doyle; Hegel, Mark T.

    2013-01-01

    Background Each year more than one-half million people die from cancer in the United States. Despite progress in increasing access to palliative oncology services, end-of-life care still needs improvement. Measuring the quality of the end-of-life experience is difficult due to patient debility and reduced consciousness as death approaches. Family proxies have been proposed as valuable informants regarding the quality of end-of-life care. This paper describes family proxy perspectives on care at the end of life in patients who died from advanced cancer Methods In the context of a novel outpatient palliative care demonstration project, 125 family proxy respondents completed a structured survey by phone 3–6 months following patients’ death from breast, lung, or gastrointestinal cancer. Four key quality of care indicators were measured: decision-making and physician communication, location of death, hospice involvement, and end-of-life symptoms. Results Proxies reported that 80% of patients completed advance directives and about half of them were helpful in guiding care; communication with physicians about end-of-life treatment wishes occurred in 67%, but less than half actually made a plan with the physician to ensure that their wishes were followed; the majority died in their location of choice, most often at home; over half had hospice involvement for an average of 41.8 days prior to death; and during the last week of life the majority of patients experienced troublesome physical and emotional symptoms. Conclusions Measurement of proxy perspectives is feasible and these results provide actionable data for areas of improvement in palliative oncology care. PMID:18306393

  6. Proxy perspectives regarding end-of-life care for persons with cancer.

    Science.gov (United States)

    Bakitas, Marie; Ahles, Tim A; Skalla, Karen; Brokaw, Frances C; Byock, Ira; Hanscom, Brett; Lyons, Kathleen Doyle; Hegel, Mark T

    2008-04-15

    Each year, greater than a half million people die of cancer in the U.S. Despite progress in increasing access to palliative oncology services, end-of-life care still needs improvement. Measuring the quality of the end-of-life experience is difficult because of patient debility and reduced consciousness as death approaches. Family proxies have been proposed as valuable informants regarding the quality of end-of-life care. This article describes family proxy perspectives concerning care at the end of life in patients who died of advanced cancer. In the context of a novel outpatient palliative care demonstration project, 125 family proxy respondents completed a structured survey by telephone 3 months to 6 months after the patient's death from breast, lung, or gastrointestinal cancer. Four key quality of care indicators were measured: decision-making and physician communication, location of death, hospice involvement, and end-of-life symptoms. Proxies reported that 78% to 81% of patients completed at least 1 form of advance directive and approximately half of them were helpful in guiding care. Communication with physicians regarding end-of-life treatment wishes occurred in 67% of cases, but only 57% of the patients actually made a plan with their physician to ensure that their wishes were followed. The majority of patients died in their location of choice, most often at home, and greater than half had hospice involvement for an average of 41.8 days before death. During the last week of life, the majority of patients experienced troublesome physical and emotional symptoms. Measurement of proxy perspectives is feasible as an indicator of the quality of end-of-life care, and the results of the current study provide actionable data for areas of improvement in palliative oncology care.

  7. Calcium isotopic composition of high-latitude proxy carrier Neogloboquadrina pachyderma (sin.

    Directory of Open Access Journals (Sweden)

    A. Eisenhauer

    2009-01-01

    Full Text Available The accurate reconstruction of sea surface temperature (SST history in climate-sensitive regions (e.g. tropical and polar oceans became a challenging task in palaeoceanographic research. Biogenic shell carbonate SST proxies successfully developed for tropical regions often fail in cool water environments. Their major regional shortcomings and the cryptic diversity now found within the major high latitude proxy carrier Neogloboquadrina pachyderma (sin. highlight an urgent need to explore complementary SST proxies for these cool-water regions. Here we incorporate the genetic component into a calibration study of a new SST proxy for the high latitudes. We found that the calcium isotopic composition (δ44/40Ca of calcite from genotyped net catches and core-top samples of the planktonic foraminifera Neogloboquadrina pachyderma (sin. is related to temperature and unaffected by genetic variations. The temperature sensitivity has been found to be 0.17 (±0.02‰ per 1°C, highlighting its potential for downcore applications in open marine cool-water environments. Our results further indicate that in extreme polar environments, below a critical threshold temperature of 2.0 (±0.5°C associated with salinities below 33.0 (±0.5‰, a prominent shift in biomineralization affects the δ44/40Ca of genotyped and core-top N. pachyderma (sin., becoming insensitive to temperature. These findings highlight the need of more systematic calibration studies on single planktonic foraminiferal species in order to unravel species-specific factors influencing the temperature sensitivity of Ca isotope fractionation and to validate the proxies' applicability.

  8. A Probabilistic Model of Chronological Errors in Layer-Counted Climate Proxies: Applications to Annually-Banded Coral Archives

    Science.gov (United States)

    Comboul, M.; Emile-Geay, J.; Evans, M. N.; Mirnateghi, N.; Cobb, K.; Thompson, D. M.

    2013-12-01

    The ability to precisely date climate proxies is central to the reconstruction of past climate variations. All climate proxies are affected by age uncertainties to some extent, and such age uncertainty is seldom quantified. This work proposes a probabilistic age model for proxies based on layer-counted chronologies, and explores its use for annually-banded coral archives. The model considers both errors due to missing rings and doubly-counted rings, which for simplicity we model as independent processes. The model can accommodate various assumptions about error rates and can be used to quantify how chronological uncertainties impact various diagnostics of variability. In one dimension, we find that time uncertainties primarily affect high-frequency signals (as expected) but also significantly bias the estimate of decadal signals. While tuning the coral data to an independent, tree-ring based chronology [Li et al., 2011] we show that correlations between the two records may be substantially improved by random age perturbations on the order of +/- 5 years per 100 bands in addition to adjustments within the error range of the U/Th dates. Using a synthetic pseudocoral network as testing ground, we quantify uncertainties in the estimation of spatiotemporal patterns of variability. Even for small error rates, the amplitude of multidecadal variability is systematically overestimated at the expense of interannual variability (ENSO, in this case), artificially flattening its spectrum at periods longer than 10 years. Finally, we present an approach to distinguish between chronologies and correct for age uncertainties within a network of time-uncertain records. The method is validated in idealized cases, where it consistently brings age-corrected chronologies closer to the true chronology. This optimization principle, however, is difficult to apply in practice due to the extremely high dimensionality of the space of plausible time perturbations. We end with a discussion of

  9. Calibration, validation and application of foraminiferal carbonate based proxies. Reconstructing temperature, salinity and sea water Mg/Ca

    NARCIS (Netherlands)

    Wit, J.C.

    2012-01-01

    The chemistry of the calcite test of foraminifera is often relating to the environmental conditions under which they lived. These so-called proxy-relations are regularly used as a tool to reconstruct past climates. Accuracy of these proxies is, however, often limited due to uncertainties or absence

  10. Pharmacological and non-pharmacological treatment preferences of healthcare professionals and proxies for challenging behaviors in patients with dementia

    NARCIS (Netherlands)

    Janus, Sarah I; van Manen, Jeannette G; van Til, Janine A; Zuidema, Sytse U; IJzerman, Maarten J.

    BACKGROUND: Prescribing antipsychotics to patients with neuropsychiatric symptoms is a matter of concern. Physicians have to make treatment decisions for patients with dementia together with proxies and/or nurses. However, it is unknown whether physicians, nurses, and proxies' treatment preferences

  11. Proxying UPnP service discovery and access to a non-IP Bluetooth network on a mobile phone

    NARCIS (Netherlands)

    Delphinanto, A.; Koonen, A.M.J.; Peeters, M.E.; Hartog, F.T.H. den

    2007-01-01

    The current service- and device discovery protocols are not platform- and network independent. Therefore, proxy servers will be needed to extend the range of IP-based discovery protocols to non-IP domains. We developed an architecture of a proxy that enables Universal Plug and Play (UPnP) devices

  12. The proxy problem anatomized: Child-parent disagreement in health related quality of life reports of chronically ill adolescents

    NARCIS (Netherlands)

    J.N.T. Sattoe (Jane); A.L. van Staa (AnneLoes); H.A. Moll (Henriëtte)

    2012-01-01

    textabstractBackground: Discrepancy between self-reports and parent-proxy reports of adolescent health-related quality of life (HRQoL) has been repeatedly acknowledged in the literature as the proxy problem. However, little is known about the extent and direction of this discrepancy. The purpose of

  13. Molybdenum isotope records as a potential new proxy for paleoceanography

    Science.gov (United States)

    Siebert, Christopher; Nägler, Thomas F.; von Blanckenburg, Friedhelm; Kramers, Jan D.

    2003-06-01

    New high-precision isotope ratios of dissolved Mo in seawater from different ocean basins and depths show a homogeneous isotope composition ('mean ocean water 98Mo/95Mo' (MOMO)), as expected from its long ocean residence time (800 kyr). This composition appears to have been constant for the past 60 Myr at a 1-3 Myr time resolution as indicated from thick sections of Fe-Mn crusts from the Atlantic and Pacific. These records yield a constant offset from MOMO (average of -3.1 and -2.9‰). They are similar to our new data on recent oxic Mo sinks: pelagic sediments and six Fe-Mn crust surface layers range from -2.7 to -2.9‰ and -2.7 to -3.1‰, respectively. Recent suboxic Mo sinks from open ocean basins display heavier and more variable isotope ratios (-0.7 to -1.6‰ relative to MOMO). Crustal Mo sources were characterized by measuring two granites (and a mild acid leach of one granite), seven volcanic rocks and two clastic sediments. All show a narrow range of compositions (-2.0 to -2.3‰). These data indicate that isotope fractionation by chemical weathering and magmatic processes is insignificant on a global scale. They therefore represent good estimates of the composition of dissolved Mo input to the oceans and that of the average continental crust. Thus, the Mo input into the oceans appears to be distributed into lighter oxic sinks and heavier reducing sinks. This is consistent with steady-state conditions in the modern ocean. The constant isotope offset between oxic sediments and seawater suggests that the relative amounts of oxic and reducing Mo removal fluxes have not varied by more than 10% over the last 60 Myr. An equilibrium fractionation process is proposed assuming that Mo isotope fractionation occurs between (dominant) MoO42- and (minor) Mo(OH)6 species in solution, of which the latter is preferentially scavenged.

  14. Human Mobility in Large Cities as a Proxy for Crime

    CERN Document Server

    Caminha, Carlos; Pequeno, Tarcisio H C; Ponte, Caio; Melo, Hygor P M; Oliveira, Erneson A; Andrade, José S

    2016-01-01

    We investigate at the subscale of the neighborhoods of a highly populated city the incidence of property crimes in terms of both the resident and the floating population. Our results show that a relevant allometric relation could only be observed between property crimes and floating population. More precisely, the evidence of a superlinear behavior indicates that a disproportional number of property crimes occurs in regions where an increased flow of people takes place in the city. For comparison, we also found that the number of crimes of peace disturbance only correlates well, and in a superlinear fashion too, with the resident population. Our study raises the interesting possibility that the superlinearity observed in previous studies [Bettencourt et al., Proc. Natl. Acad. Sci. USA 104, 7301 (2007) and Melo et al., Sci. Rep. 4, 6239 (2014)] for homicides versus population at the city scale could have its origin in the fact that the floating population, and not the resident one, should be taken as the relev...

  15. Proxies for soil organic carbon derived from remote sensing

    Science.gov (United States)

    Rasel, S. M. M.; Groen, T. A.; Hussin, Y. A.; Diti, I. J.

    2017-07-01

    The possibility of carbon storage in soils is of interest because compared to vegetation it contains more carbon. Estimation of soil carbon through remote sensing based techniques can be a cost effective approach, but is limited by available methods. This study aims to develop a model based on remotely sensed variables (elevation, forest type and above ground biomass) to estimate soil carbon stocks. Field observations on soil organic carbon, species composition, and above ground biomass were recorded in the subtropical forest of Chitwan, Nepal. These variables were also estimated using LiDAR data and a WorldView 2 image. Above ground biomass was estimated from the LiDAR image using a novel approach where the image was segmented to identify individual trees, and for these trees estimates of DBH and Height were made. Based on AIC (Akaike Information Criterion) a regression model with above ground biomass derived from LiDAR data, and forest type derived from WorldView 2 imagery was selected to estimate soil organic carbon (SOC) stocks. The selected model had a coefficient of determination (R2) of 0.69. This shows the scope of estimating SOC with remote sensing derived variables in sub-tropical forests.

  16. Adolescent self-report and parent proxy-report of health-related quality of life: an analysis of validity and reliability of PedsQL 4.0 among a sample of Malaysian adolescents and their parents.

    Science.gov (United States)

    Kaartina, Sanker; Chin, Yit Siew; Fara Wahida, Rezali; Woon, Fui Chee; Hiew, Chu Chien; Zalilah, Mohd Shariff; Mohd Nasir, Mohd Taib

    2015-04-08

    The Pediatric Quality of Life Inventory Generic Core Scales (PedsQL) 4.0 is a generalized assessment of health-related quality of life (HRQoL) based on adolescent self-report and parent proxy-report. This study aims to determine the construct validity and reliability of PedsQL 4.0 among a sample of Malaysian adolescents and parents. A cross-sectional study was carried out at three selected public schools in the state of Selangor. A total of 379 Malaysian adolescents completed the PedsQL 4.0 adolescent self-report and 218 (55.9%) parents completed the PedsQL 4.0 parent proxy-report. Weight and height of adolescents were measured and BMI-for-age by sex was used to determine their body weight status. There were 50.8% male and 49.2% female adolescents who participated in this study (14.25 ± 1.23 years). The prevalence of overweight and obesity (25.8%) was four times higher than the prevalence of severe thinness and thinness (6.1%). Construct validity was analyzed using Confirmatory Factor Analysis (CFA). Based on CFA, adolescent self-report and parent proxy-report met the criteria of convergent validity (factor loading > 0.5, Average Variance Extracted (AVE) > 0.5, Construct Reliability > 0.7) and showed good fit to the data. The adolescent self-report and parent proxy-report exhibited discriminant validity as the AVE values were larger than the R(2) values. Cronbach's alpha coefficients of the adolescent self-report (α = 0.862) and parent proxy-report (α = 0.922) showed these instruments are reliable. Parents perceived the HRQoL of adolescents was poorer compared to the perception of the adolescent themselves (t = 5.92, p 0.05). Parent proxy-report was negatively associated with the adolescents' BMI-for-age (r = -0.152, p 0.05). Adolescent self-report and parent proxy-report of the PedsQL 4.0 are valid and reliable to assess HRQoL of Malaysian adolescents. Future studies are recommended to use both adolescent self-report and parent-proxy report of HRQoL as

  17. Solar Diameter Measurements from Eclipses as a Solar Variability Proxy

    Science.gov (United States)

    Waring Dunham, David; Sofia, Sabatino; Guhl, Konrad; Herald, David Russell

    2015-08-01

    Since thermal relaxation times for the Sun are thousands of years, small variations of the Solar intensity are proportional to small variations of the Solar diameter on decadal time scales. In a combination between observations and theory, reliable values of the relation constant W are known, that allow transformation of historical variations of radius into variations of the solar luminosity. During the past 45 years, members of the International Occultation Timing Association (IOTA) have observed 20 annular and total solar eclipses from locations near the path edges. Baily’s beads, whose occurrence and duration are considerably prolonged as seen from path edge locations, were first timed visually, mostly using projection techniques, but since about 1980, they have been timed mainly from analysis of video recordings. The edge locations have the advantage that most of the beads are defined by the same features in the lunar polar regions that cause the phenomena at each eclipse. Some of the best-observed modern eclipses can be used to assess the accuracy of the results, which are limited mainly by the intensity drop at the Sun’s edge, and the consequent uncertainty in defining the edge. In addition, direct visual contact timings made near the path edges during earlier eclipses, back to 1715, have been found in the literature, and analyzed. Although the observations seem to show small variations, they are only a little larger than the assessed accuracies. The results can be improved with a consistent re-analysis of the observations using the much more accurate lunar profile data that is now available from the Japanese Kaguya and NASA’s LRO lunar orbiter observations. Also, IOTA has plans to observe future eclipses with a variety of techniques that were used in the past, to better assess the accuracies of the different observational methods that have been used, and determine any systematic differences between them.

  18. Can we use ice calving on glacier fronts as a proxy for rock slope failures?

    Science.gov (United States)

    Abellan, Antonio; Penna, Ivanna; Daicz, Sergio; Carrea, Dario; Derron, Marc-Henri; Jaboyedoff, Michel; Riquelme, Adrian; Tomas, Roberto

    2015-04-01

    Ice failures on glacier terminus show very similar fingerprints to rock-slope failure (RSF) processes, nevertheless, the investigation of gravity-driven instabilities that shape rock cliffs and glacier's fronts are currently dissociated research topics. Since both materials (ice and rocks) have very different rheological properties, the development of a progressive failure on mountain cliffs occurs at a much slower rate than that observed on glacier fronts, which leads the latter a good proxy for investigating RSF. We utilized a terrestrial Laser Scanner (Ilris-LR system from Optech) for acquiring successive 3D point clouds of one of the most impressive calving glacier fronts, the Perito Moreno glacier located in the Southern Patagonian Ice Fields (Argentina). We scanned the glacier terminus during five days (from 10th to 14th of March 2014) with very high accuracy (0.7cm standard deviation of the error at 100m) and a high density of information (200 points per square meter). Each data series was acquired at a mean interval of 20 minutes. The maximum attainable range for the utilized wavelength of the Ilris-LR system (1064 nm) was around 500 meters over massive ice (showing no-significant loss of information), being this distance considerably reduced on crystalline or wet ice short after the occurrence of calving events. As for the data treatment, we have adapted our innovative algorithms originally developed for the investigation of both precursory deformation and rockfalls to study calving events. By comparing successive three-dimensional datasets, we have investigated not only the magnitude and frequency of several ice failures at the glacier's terminus (ranging from one to thousands of cubic meters), but also the characteristic geometrical features of each failure. In addition, we were able to quantify a growing strain rate on several areas of the glacier's terminus shortly after their final collapse. For instance, we investigated the spatial extent of the

  19. COS as a proxy for photosynthesis: foliage and soil contributions to ecosystem COS flux

    Science.gov (United States)

    Erkkilä, Kukka-Maaria; Kooijmans, Linda; Aalto, Juho; Chen, Huilin; Mammarella, Ivan; Maseyk, Kadmiel; Pihlatie, Mari; Seibt, Ulli; Sun, Wu; Vesala, Timo

    2017-04-01

    Traditionally the photosynthetic sink of CO2 (described by gross primary production, GPP) is defined from ecosystem scale measurements of CO2 flux taking into account respiration defined from the nighttime CO2 flux data. The problem with this method is the accurate determination of ecosystem respiration, since the respiratory processes can vary remarkably between daytime and nighttime. Carbonyl sulfide (COS) has been suggested to be a useful proxy for GPP since plants take up COS in a similar way as CO2 via their stomata. In contrast to CO2, there is no back-flux (respiration) of COS by plants and GPP can be calculated directly from COS flux measurements. However, leaf relative uptake (LRU) ratio, that is used when converting COS flux into GPP with a linear relation, has been treated as a constant and needs to be better determined for more accurate GPP estimates. This presentation shows the preliminary results of a measurement campaign organized in Hyytiälä Scots pine (Pinus sylvestris) stand in southern Finland during the growing season 2016. COS fluxes from the soil were measured with soil chambers over different vegetations. Pine and aspen branches were measured with branch chambers and ecosystem scale exchange was monitored via eddy covariance measurements. Preliminary results show night-time ecosystem uptake of COS (negative flux) that is about 15% of the daily uptake. Soil chambers show constantly negative COS fluxes, although there is no uptake of CO2 and the soil flux is about 25% of the total ecosystem flux. Pine and aspen branches seem to be sinks of COS throughout the day indicating open stomata during night-time. These findings suggest that negative ecosystem COS flux can be explained by soil and vegetation uptake during night-time. From branch chamber measurements we were able to calculate the leaf relative uptake (LRU) separately for aspen and pine. We find that LRU has an exponential correlation with photosynthetic active radiation (PAR) when PAR

  20. The C32 alkane-1,15-diol as a proxy of late Quaternary riverine input in coastal margins

    Directory of Open Access Journals (Sweden)

    J. Lattaud

    2017-08-01

    Full Text Available The study of past sedimentary records from coastal margins allows us to reconstruct variations in terrestrial input into the marine realm and to gain insight into continental climatic variability. There are numerous organic proxies for tracing terrestrial input into marine environments but none that strictly reflect the input of river-produced organic matter. Here, we test the fractional abundance of the C32 alkane 1,15-diol relative to all 1,13- and 1,15-long-chain diols (FC32 1, 15 as a tracer of input of river-produced organic matter in the marine realm in surface and Quaternary (0–45 ka sediments on the shelf off the Zambezi and nearby smaller rivers in the Mozambique Channel (western Indian Ocean. A Quaternary (0–22 ka sediment record off the Nile River mouth in the eastern Mediterranean was also studied for long-chain diols. For the Mozambique Channel, surface sediments of sites most proximal to Mozambique rivers showed the highest F1, 15 − C32 (up to 10 %. The sedimentary record shows high (15–35 % pre-Holocene F1, 15 − C32 and low (< 10 % Holocene F1, 15 − C32 values, with a major decrease between 18 and 12 ka. F1, 15 − C32 is significantly correlated (r2 =  0.83, p < 0.001 with the branched and isoprenoid tetraether (BIT index, a proxy for the input of soil and river-produced organic matter in the marine environment, which declines from 0.25 to 0.60 for the pre-Holocene to < 0.10 for the Holocene. This decrease in both FC32 1, 15 and the BIT is interpreted to be mainly due to rising sea level, which caused the Zambezi River mouth to become more distal to our study site, thereby decreasing riverine input at the core location. Some small discrepancies are observed between the records of the BIT index and FC32 1, 15 for Heinrich Event 1 (H1 and the Younger Dryas (YD, which may be explained by a change in soil sources in the catchment area rather than a change in

  1. Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.

    Science.gov (United States)

    Smiljanić, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Stajić, Branko; Wilmking, Martin

    2014-12-01

    Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Multi-Objective History Matching with a Proxy Model for the Characterization of Production Performances at the Shale Gas Reservoir

    Directory of Open Access Journals (Sweden)

    Jaejun Kim

    2017-04-01

    Full Text Available This paper presents a fast, reliable multi-objective history-matching method based on proxy modeling to forecast the production performances of shale gas reservoirs for which all available post-hydraulic-fracturing production data, i.e., the daily gas rate and cumulative-production volume until the given date, are honored. The developed workflow consists of distance-based generalized sensitivity analysis (DGSA to determine the spatiotemporal-parameter significance, fast marching method (FMM as a proxy model, and a multi-objective evolutionary algorithm to integrate the dynamic data. The model validation confirms that the FMM is a sound surrogate model working within an error of approximately 2% for the estimated ultimate recovery (EUR, and it is 11 times faster than a full-reservoir simulation. The predictive accuracy on future production after matching 1.5-year production histories is assessed to examine the applicability of the proposed method. The DGSA determines the effective parameters with respect to the gas rate and the cumulative volume, including fracture permeability, fracture half-length, enhanced permeability in the stimulated reservoir volume, and average post-fracturing porosity. A comparison of the prediction accuracy for single-objective optimization shows that the proposed method accurately estimates the recoverable volume as well as the production profiles to within an error of 0.5%, while the single-objective consideration reveals the scale-dependency problem with lesser accuracy. The results of this study are useful to overcome the time-consuming effort of using a multi-objective evolutionary algorithm and full-scale reservoir simulation as well as to conduct a more-realistic prediction of the shale gas reserves and the corresponding production performances.

  3. Tracking fluctuations in the intensity of the eastern tropical north Pacific oxygen minimum zone using a multi-proxy approach

    Science.gov (United States)

    Tems, C.

    2015-12-01

    Naturally occurring oxygen minimum zones (OMZs) are permanent midwater features that are associated with highly productive regions of the ocean, key microbial mediated biogeochemical cycling, and the deposition of organic rich sediments. The intensity of OMZs varies on glacial to interglacial time scales, indicating a relationship between the climate system and the expanse of OMZs, however, high-resolution studies tracking the fluctuations of OMZs on a near annual basis are lacking. In the Gulf of California (Pescadero Slope), the eastern tropical north Pacific OMZ impinges on basin slopes depositing laminated, hemipelagic sediments that record useful proxies of OMZ fluctuations. In an OMZ, low O2 content promotes water column denitrification, imparting an elevated 15N/14N isotopic signature on the residual nitrate in the water column. The elevated 15NO3- is upwelled and incorporated into particulate organic mater (POM) during primary production. The exported POM δ15Nsed then reflects the intensity of the regional OMZ at the time it was deposited. The Pescadero Slope record shows distinct temporal fluctuations in the δ15Nsed with decadal to multi-decadal and centennial cyclicity over the past 1200 years. The record reveals that the OMZ contracts during warmer climatic periods, including the Medieval Climate Optimum and the Industrial Revolution, and expands during cooler climates, specifically the Little Ice Age. The local mechanisms that are influencing fluctuations in the OMZ are investigated through an analysis of productivity proxies, including weight percent organic carbon and weight percent biogenic silica, and indicate OMZ expansion during periods of high productivity. Local productivity is driven by the intensity in the easterly trade winds in the Pacific, and thus the relationship between regional trade wind intensity and fluctuations in the intensity of the OMZ over the past 160 years will be discussed.

  4. Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach

    Science.gov (United States)

    Affouri, Aida; Dezileau, Laurent; Kallel, Nejib

    2017-06-01

    Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe / Ca and Ti / Ca) characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995). Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

  5. Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia: a multi-proxy approach

    Directory of Open Access Journals (Sweden)

    A. Affouri

    2017-06-01

    Full Text Available Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe ∕ Ca and Ti ∕ Ca characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995. Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

  6. A 481-year chronology of oak earlywood vessels as an age-independent climatic proxy in NW Iberia

    Science.gov (United States)

    Souto-Herrero, Manuel; Rozas, Vicente; García-González, Ignacio

    2017-08-01

    The earlywood vessels of ring-porous trees can be analyzed dendrochronologically and used as a proxy for environmental information. However, most works deal with the analysis of contemporary climate-growth relationships and do not evaluate their long-term variation. We obtained a 481-year chronology of earlywood vessel size of oak (Quercus robur L.) in the northwestern Iberian Peninsula, investigated its behavior through time, and compared it to a chronology of younger trees developed at the same site. We expressed earlywood vessel size as the hydraulically-weighted diameter (DH) and discriminated between vessels in the first row (r1) and the rest of the vessels (nr1); radial increment was assessed from latewood width (LW). Climate-growth relationships were strong and nearly identical for both age classes. Spring temperature positively affected vessel size, but only for the first row, probably mediating the onset of cambial activity. The chronology of old trees showed an almost flat age trend, except for the first decades, and series were not affected by stand dynamics. In contrast, LW had a weak response to climate, probably because of the high impact of abrupt growth changes. There was a high negative correlation between DH and the winter North Atlantic Oscillation Index (NAO), which was unstable during the 20th century. To our knowledge, this is the longest chronology of earlywood vessel size obtained to date, and offers promising results, as this proxy is shown to be independent of age and forest disturbances, and was strongly correlated to climate across long time spans.

  7. Nuclear magnetic resonance relaxation and diffusion measurements as a proxy for soil properties

    Science.gov (United States)

    Duschl, Markus; Pohlmeier, Andreas; Galvosas, Petrik; Vereecken, Harry

    2013-04-01

    correlated the results with various soil properties like texture, water retention parameters, and hydraulic conductivity. This way we show that we can predict soil properties by NMR measurements and that we are able use results of NMR measurements as a proxy without the need of direct measurements. [1] Song, Y.-Q., Vadose Zone Journal, 9 (2010) [2] Stingaciu, L. R., et al., Water Resources Research, 46 (2010) [3] Vogt, C., et al., Journal of Applied Geophysics, 50 (2002) [4] Barrie, P. J., Annual Reports on NMR Spectroscopy, 41 (2000) [5] Stallmach, F., Galvosas, P., Annual Reports on NMR Spectroscopy, 61 (2007)

  8. Heterogeneity of Cr in Mytilus edulis: Implications for the Cr isotope system as a paleo-redox proxy

    Science.gov (United States)

    Bruggmann, Sylvie; Klaebe, Robert; Frei, Robert

    2017-04-01

    Changes in 53Cr/52Cr (δ53Cr) values recorded by biogenic carbonates are emerging as a proxy for variations in the redox state of the Earth's oceans and atmosphere (e.g. [1], [2]). We investigate the ability of modern carbonate shells (Mytilus edulis) to record the δ53Cr composition of ambient seawater in order to assess their utility as a paleo-redox proxy. Samples of cultivated M. edulis from the Kiel Fjord, Germany, were analyzed for their δ53Cr composition and Cr concentrations [Cr] using TIMS. To disentangle the pathway of Cr into the carbonate shell, a series of step-digestions of their organic outer sheaths (periostraca) and their intra-layer composition were performed. Bulk analyses of specimens with intact periostraca returned 16 to 34 ppb Cr with δ53Cr values ranging from 0.28 to 0.65 ± 0.1 (2SE) and thus fall within the range of surface seawater from the Baltic Sea (0.3 - 0.6 \\permil [3]). Partial removal of periostraca resulted in lower [Cr] (5 to 17 ppb) and δ53Cr values (-0.05 ± 0.15 \\permil). These results show a positive correlation between the amount of organic matter present in a sample and both [Cr] and δ53Cr (n = 9). With nearly complete removal of periostraca, the remaining [Cr] is significantly lower (less than 5 ppb) and can only be accessed by incineration of the carbonate shell. The correlation between [Cr], δ53Cr and the amount of periostracum present in bulk samples indicates that a significant proportion of preserved Cr may be associated with the organic outer sheath. The Cr endmember accessed after incineration is less likely associated with the carbonate crystal lattice. Instead, the δ53Cr values obtained after incineration are similar to those reported from terrestrial rocks, suggesting the influence of detrital particles. Alternatively, Cr may be reduced and subsequently re-oxidized during the mineralization of biogenic carbonates [4]. Seasonal changes in primary productivity in seawater may further influence the shell

  9. P/Ca in Gastropod Shells as a Nutrient Proxy in Tropical Marine Environments

    Science.gov (United States)

    Grossman, E. L.; Tao, K.; Robbins, J.; O'Dea, A.

    2013-12-01

    Nutrient status and its stability play key roles in the maintenance of marine ecosystems, both in modern and ancient oceans. Modern coral reef communities in the Caribbean are being threatened by anthropogenic input of nutrients whereas one to two million years ago, communities in this same region experienced dramatic overturn of corals and mollusks with the uplift of the Central American Isthmus and subsequent reduction of upwelling-derived nutrients. Thus the ability to record past and present nutrient delivery is paramount for understanding the role of environmental change in controlling past and future biodiversity. To test trace element chemistries in gastropod shells as nutrient proxies, we measured the trace element (Mg, Sr, Ba, Mn, Fe, P, and U ) and stable isotopic (δ18O, δ13C) compositions of 11 modern Conus specimens collected from upwelling and non-upwelling regions in the Caribbean and Pacific coasts of Panama. Four Caribbean shells represent non-upwelling conditions, while seven Pacific shells record conditions of seasonal upwelling (Gulf of Panama) or shoaling of the thermocline (Gulf of Chiriquí). Shells were serially sampled around the spire at 2-3 mm intervals, providing roughly monthly resolution. Shallow-dwelling Pacific specimens show large seasonal range in δ18O (>2‰) reflecting upwelling during the dry season and freshening during the rainy season. In contrast, shallow-dwelling Caribbean specimens show small δ18O range (mostly ≤1‰) indicating limited seasonal upwelling and freshening. For trace element analyses, about 100 μg of carbonate powder was dissolved in 2 ml of 2% HNO3 and analyzed on a high resolution, inductively-coupled plasma mass spectrometer (HR-ICP-MS). Among the wide array of trace elements analyzed, only Sr/Ca shows a significant correlation with upwelling intervals, as indicated by high δ18O. This reflects the positive relationship between Sr/Ca and temperature in Conus shells (Sosdian et al., 2006, G3, Q11023

  10. An Anonymous Access Authentication Scheme Based on Proxy Ring Signature for CPS-WMNs

    Directory of Open Access Journals (Sweden)

    Tianhan Gao

    2017-01-01

    Full Text Available Access security and privacy have become a bottleneck for the popularization of future Cyber-Physical System (CPS networks. Furthermore, users’ need for privacy-preserved access during movement procedure is more urgent. To address the anonymous access authentication issue for CPS Wireless Mesh Network (CPS-WMN, a novel anonymous access authentication scheme based on proxy ring signature is proposed. A hierarchical authentication architecture is presented first. The scheme is then achieved from the aspect of intergroup and intragroup anonymous mutual authentication through proxy ring signature mechanism and certificateless signature mechanism, respectively. We present a formal security proof of the proposed protocol with SVO logic. The simulation and performance analysis demonstrate that the proposed scheme owns higher efficiency and adaptability than the typical one.

  11. A study of practical proxy reencryption with a keyword search scheme considering cloud storage structure.

    Science.gov (United States)

    Lee, Sun-Ho; Lee, Im-Yeong

    2014-01-01

    Data outsourcing services have emerged with the increasing use of digital information. They can be used to store data from various devices via networks that are easy to access. Unlike existing removable storage systems, storage outsourcing is available to many users because it has no storage limit and does not require a local storage medium. However, the reliability of storage outsourcing has become an important topic because many users employ it to store large volumes of data. To protect against unethical administrators and attackers, a variety of cryptography systems are used, such as searchable encryption and proxy reencryption. However, existing searchable encryption technology is inconvenient for use in storage outsourcing environments where users upload their data to be shared with others as necessary. In addition, some existing schemes are vulnerable to collusion attacks and have computing cost inefficiencies. In this paper, we analyze existing proxy re-encryption with keyword search.

  12. Surrogate Decision Makers and Proxy Ownership: Challenges of Privacy Management in Health Care Decision Making

    Science.gov (United States)

    Bute, Jennifer J.; Petronio, Sandra; Torke, Alexia M.

    2016-01-01

    This study explored the communicative experiences of surrogates who served as decision makers for patients who were unable to convey health information and choices about treatment options. Drawing on assumptions from communication privacy management theory (Petronio, 2002), 35 surrogates were interviewed to explore how they navigated the role of guardian of patients’ private health information while the patient was hospitalized. This research determined that surrogates are not only guardians and thereby co-owners of the patients’ private health information, they actually served in a “proxy ownership” role. Surrogates described obstacles to both obtaining and sharing private health information about the patient, suggesting that their rights as legitimate co-owners of the patients’ information were not fully acknowledged by the medical teams. Surrogates also described challenges in performing the proxy ownership role when they were not fully aware of the patient's wishes. Theoretical and practical implications of these challenges are discussed. PMID:25175060

  13. Validity of proxy-reported height and weight to derive body mass index in adults participating in Special Olympics.

    Science.gov (United States)

    Dobranowski, Kristin; Lloyd, Meghann; Côté, Pierre; Balogh, Robert

    2017-02-16

    Overweight and obesity are common in adults with intellectual disabilities, which complicates their health. To meet their health needs, individuals with intellectual disability frequently rely on proxies to answer questions on their behalf. In the general population, the use of proxy-reported height and weight to compute body mass index (BMI) has been validated, but not among adults with intellectual disability. The objective of this study was to determine the accuracy of proxy-reported height, weight and derived BMI among adults with intellectual disability. Proxies were asked to report height and weight on behalf of adults with intellectual disability who participate in Special Olympics Ontario; their answers were compared to measured height and weight. Proxies reported height and weight accurately; the sensitivity of proxy reports for classifying individuals with intellectual disability as overweight and/or obese was 84.6%. Proxy reports may be useful when direct measurements of individuals with intellectual disability are not available. © 2017 John Wiley & Sons Ltd.

  14. The potential of carbonyl sulfide as a proxy for gross primary production at flux tower sites

    Science.gov (United States)

    Blonquist, J. Mark, Jr.

    Seasonal dynamics of atmospheric carbonyl sulfide (OCS) at regional and continental scales and plant OCS exchange at the leaf level have shown a close relationship with those for CO2. CO2 has both sinks and sources within terrestrial ecosystems, but the primary terrestrial exchange for OCS is thought to be leaf uptake, suggesting potential for OCS uptake as a proxy for gross primary production (GPP). The utility of OCS uptake as a GPP proxy in micrometeorological studies of biosphere-atmosphere CO2 exchange was explored by applying theoretical concepts from earlier OCS studies to estimate GPP. Measured net ecosystem exchange (NEE) was partitioned using the ratio of measured vertical mole fraction gradients of OCS and CO2. At the Harvard Forest AmeriFlux site, measured CO2 and OCS vertical gradients were correlated, and were related to NEE and GPP, respectively. Estimates of GPP from OCS-based NEE partitioning were similar to those from established regression techniques, providing evidence that OCS uptake can potentially serve as a GPP proxy. Measured vertical CO 2 mole fraction gradients at five other AmeriFlux sites were used to project anticipated vertical OCS mole fraction gradients to provide indication of potential OCS signal magnitudes at sites where no OCS measurements were made. Projected OCS gradients at sites with short canopies were greater than those in forests, including measured OCS gradients at Harvard Forest, indicating greater potential for OCS uptake as a GPP proxy at these sites. This exploratory study suggests that continued investigation of linkages between OCS and GPP is warranted.

  15. Testing Novel pH Proxies through Inorganic Calcite Precipitations and K/Pg Foraminifera

    Science.gov (United States)

    Super, J. R.; Pagani, M.; Wang, Z.

    2013-12-01

    Ocean pH proxies help constrain the carbon system in the paleocean and can be used to infer atmospheric CO2 when coupled with estimates of total alkalinity, aqueous pCO2 or dissolved inorganic carbon. This project investigates two novel pH proxies (cerium abundance and kinetically-controlled oxygen isotopes) through a series of precipitations of inorganic calcite, as well as the previously established boron isotope pH proxy. Precipitations are performed using varied pH and carbonate saturation states that span the range of typical ocean values as well as a 'free drift' that allows pH and saturation state to vary. The light rare earth element cerium speciates, depending on local oxidation-reduction conditions, between the soluble Ce3+ and highly insoluble Ce4+ ions, causing a relative depletion of cerium in ocean water. This project demonstrates how a suite rare earth elements, including cerium, partitions into inorganic calcite and how partitioning varies with changing pH and carbonate saturation state. Oxygen isotope fractionation is primarily controlled by temperature, but this project examines how pH and carbonate saturation state correlate with oxygen isotope values under kinetic conditions during the initial stage of precipitation. The effect of diagenesis on each proxy is simulated by dissolution of precipitated calcite in a pressure vessel. Results from the precipitations are used to inform a record of well-preserved benthic and planktonic foraminifera from DSDP Site 356 that range in age from the K/Pg boundary to the period when the δ13C gradient between the surface and deep ocean returned to pre-event levels. The pH record is used to infer the magnitude and length of the perturbation to the oceanic carbon system following the extinction event, particularly in terms of export productivity.

  16. Distance-based kriging relying on proxy simulations for inverse conditioning

    OpenAIRE

    Ginsbourger, David; Rosspopoff, Bastien; Pirot, Guillaume; Durrande, Nicolas; Renard, Philippe

    2013-01-01

    We consider the problem of rapidly identifying, among a large set of candidate parameter fields, a subset of candidates whose responses computed by accurate forward flow and transport simulation match a reference response curve. In order to keep the number of calls to the flow simulator computationally tractable, a recent distance-based approach relying on fast proxy simulations is revisited, and turned into a non-stationary Kriging method. The covariance kernel is obtained by combining a cla...

  17. Acute kidney injury in a child: A case of Munchausen syndrome by proxy.

    Science.gov (United States)

    Mantan, Mukta; Dhingra, Dhulika; Gupta, Aditi; Sethi, Gulshan Rai

    2015-11-01

    Renal and urologic problems in pediatric condition falsification (PCF) or Munchausen by proxy (MSP) can result in serious diagnostic dilemma. Symptoms of hematuria, pyuria and recurrent urinary tract infections have occasionally been described. However, MSP presenting as azotemia has not been previously reported. We describe the case of an unfortunate boy who had to undergo unnecessary hemodialysis for persistent hyperkalemia and azotemia before a final diagnosis of the falsification of investigations by the parents was made.

  18. Acute kidney injury in a child: A case of Munchausen syndrome by proxy

    Directory of Open Access Journals (Sweden)

    Mukta Mantan

    2015-01-01

    Full Text Available Renal and urologic problems in pediatric condition falsification (PCF or Munchausen by proxy (MSP can result in serious diagnostic dilemma. Symptoms of hematuria, pyuria and recurrent urinary tract infections have occasionally been described. However, MSP presenting as azotemia has not been previously reported. We describe the case of an unfortunate boy who had to undergo unnecessary hemodialysis for persistent hyperkalemia and azotemia before a final diagnosis of the falsification of investigations by the parents was made.

  19. A novel salinity proxy based on Na incorporation into foraminiferal calcite

    Directory of Open Access Journals (Sweden)

    J. C. Wit

    2013-10-01

    Full Text Available Salinity and temperature determine seawater density, and differences in both thereby control global thermohaline circulation. Whereas numerous proxies have been calibrated and applied to reconstruct temperature, a direct and independent proxy for salinity is still missing. Ideally, a new proxy for salinity should target one of the direct constituents of dissolved salt, such as [Na+] or [Cl−]. This study investigates the impact of salinity on foraminiferal Na/Ca values by laser ablation ICP-MS analyses of specimens of the benthic foraminifer Ammonia tepida cultured at a range of salinities (30.0–38.6. Foraminifera at lower salinities (30.0 and 32.5 added more chambers (10–11 to their test over the course of the culturing experiment than those maintained at higher salinities (36.1, 7–8 chambers, and 38.6, 6–7 chambers, suggesting that growth rates in this species are promoted by lower salinities. The Na/Ca of cultured specimens correlates significantly with seawater salinity (Na/Ca = 0.22S–0.75, R2 = 0.96, p DNa vary between 5.17 and 9.29 mmol mol−1 and 0.12–0.16 × 10−3, which are similar to values from inorganic precipitation experiments. The significant correlation between test size and Na/Ca results from co-variation with salinity. This implies that foraminiferal Na/Ca could serve as a robust and independent proxy for salinity, enabling salinity reconstructions independent of calcitic δ18O.

  20. Corporate Governance Objectives of Labor Union Shareholders: Evidence from Proxy Voting

    OpenAIRE

    Ashwini K. Agrawal

    2012-01-01

    Labor union pension funds have become increasingly vocal in governance matters; however, their motives are subject to fierce debate. I examine the proxy votes of AFL-CIO union funds around an exogenous change in the union representation of workers across firms. AFL-CIO-affiliated shareholders become significantly less opposed to directors once the AFL-CIO labor organization no longer represents a firm's workers. Other institutional investors, including mutual funds and public pension funds, d...

  1. A New Quantum Proxy Multi-signature Scheme Using Maximally Entangled Seven-Qubit States

    Science.gov (United States)

    Cao, Hai-Jing; Zhang, Jia-Fu; Liu, Jian; Li, Zeng-You

    2016-02-01

    In this paper, we propose a new secure quantum proxy multi-signature scheme using seven-qubit entangled quantum state as quantum channels, which may have applications in e-payment system, e-government, e-business, etc. This scheme is based on controlled quantum teleportation. The scheme uses the physical characteristics of quantum mechanics to guarantee its anonymity, verifiability, traceability, unforgetability and undeniability.

  2. CAN ACCOUNTING INFORMATION ACT AS A PROXY FOR EX ANTE UNCERTAINTY IN INITIAL PUBLIC OFFERINGS?

    OpenAIRE

    Tatang Ary Gumanti

    2003-01-01

    This paper reviews and summarizes previous works and the rationale for the proposition that accounting information is in fact value relevant in the determination of an initial public offering IPO).Theoretical and empirical evidence has indicated that certain accounting measures can he used as proxies for total firm risk, that is, they could determine the riskiness of a corporation. The literature also advocates that accounting information is relevant in determining the value and thus the risk...

  3. Evolution of Microbial Carbonates During Early Burial: A Multi-Proxy Approach

    Science.gov (United States)

    Pederson, Chelsea; Klaus, James; Swart, Peter; McNeill, Donald

    2017-04-01

    This study provides a geochemical and textural characterization of modern, Holocene, and Pleistocene palustrine microbial muds and associated organic matter along the low-energy shoreline of the Florida Everglades, USA. Dense organic-rich, light brown carbonate muds are deposited above karstified Pleistocene limestone. Deposited in shallow freshwater, the palustrine mud is a result of precipitation induced by cyanobacterial photosynthesis, and reflects local water chemistry and hydrologic conditions. The microbial community forms a dense mat, and excretes exopolymeric substances (EPS) and other labile organic constituents, in which texturally complex, fine-grained low-Mg calcite (LMC) crystals precipitate. Geochemically, this deposit is characterized by high amounts of TOC (up to 12%), a depleted organic δ13C signal indicative of microbial activity, and a low range of inorganic δ18O and δ13C values reflecting freshwater deposition. Within the Holocene microbial mud sequence, depositional and burial environments (freshwater, brackish, and full marine) can be inferred through variation in geochemical signatures, which arise from differences in depositional fluids, vegetation type, and metabolic processes of organic degradation. Stable isotope values indicate that an increased marine influence causes more positive δ18O values, whereas a freshwater source is characterized by more negative values. Inorganic δ13C of the Holocene sequence likely represents biological influence, and shows a fairly large range of up to 5‰ whereas sediments within the marine burial environment have a much lower range (˜1.5). Depending on the method of organic decomposition (aerobic, anaerobic, etc.), different δ13C signatures are recorded in both the organic and inorganic fraction. Holocene cores indicate that the freshwater environment degrades organic material via denitrification during early burial, whereas the mangrove transition zone (greater marine influence) likely breaks

  4. Developing a Metal Proxy for the Rise of Early Terrestrial Life

    Science.gov (United States)

    Rochelle, S. P.; Anbar, A. D.; Hartnett, H. E.; Romaniello, S. J.; Poret-Peterson, A. T.

    2015-12-01

    Previous work has shown that the presence of biological soil crusts (BSCs) may affect the concentrations of uranium and other transition metals by influencing metal dissolution, solubility, and transport.(1) These effects may provide a proxy for the presence of microbial mat communities in paleosols, possibly constraining the timing of the rise of early terrestrial ecosystems. Thus, in an effort to uncover possible biosignatures, this study examines metal abundances in modern desert BSCs as a possible analogue for early terrestrial life.We present results from a preliminary study comparing crusted and uncrusted soils from a low-desert site near Casa Grande, Arizona. Seventeen 5-cm soil cores were collected and the bulk elemental composition of the top 1 cm of crusted (9 samples) and non-crusted (8 samples) soils were analyzed by quadrupole ICP-MS with a typical measurement precision between 2-5%. Metal concentrations were normalized to aluminum (Al) to minimize dilution effects due to variations in carbonate and quartz content.Although the mean concentrations of nearly all elements were similar in crusted and uncrusted sites, the variability in the normalized concentrations of some of the elements, such as uranium, were different between crusted and uncrusted sites. The average U/Al ratio at the crusted site was 25 ± 1 μg U/ g Al and the average U/Al ratio at the uncrusted site was 27 ± 4 µg U/ g Al. Bartlett's and Levene's tests were used to confirm that the U/Al ratio was significantly more variable in the uncrusted sites as compared to the crusted sites. Iron (Fe), vanadium (V) and cesium (Cs) showed a similar pattern which was significant under Bartlett's but not Levene's test.As U, Fe, and V solubility and transport are redox-sensitive, we hypothesize that their aqueous mobility could have been impacted by diurnal redox swings in the photosynthetic crusts, possibly resulting in the homogenization of local cm-scale variations in background soil

  5. A Proxy Calibration Monitoring Technique for the NCAR Airborne W-band Radar

    Science.gov (United States)

    Rilling, Robert; Romatschke, Ulrike; Vivekanandan, Jothiram; Ellis, Scott M.

    2017-04-01

    The National Center for Atmospheric Research (NCAR) has recently tested and deployed its new 94 GHz HIAPER Cloud Radar (HCR). HCR is a scanning W-band system, mounted in an under-wing pod on the National Science Foundation/NCAR High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER, a Gulfstream-V). In order to ensure operational accuracy of this radar, the technique of Li, et al. (2005) has been reformulated to provide a simple means of estimating reflectivity bias using routine measurements of the ocean surface scattering. The methodology and formulation for reflectivity bias determination will be described, along with bias determination results from the 2015 Cloud Systems Evolution in the Trades (CSET) experiment. The HCR radar system is subjected to extreme changes in its operational environment that can cause changes in component response that affect radar calibration. While engineering efforts have focused on temperature and pressure stabilization of the wing pod, along with internal vessel and component temperature monitoring, it is recognized that some form of independent and ongoing verification of calibration stability is desired. When available, ocean surface scanning, with an assumed knowledge of ocean surface backscatter cross-section, can provide a useful proxy for this calibration. Therefore, during the CSET experiment, special care was taken to collect ocean scanning data during short episodes of stable flight with no clouds present; scans were coordinated with atmospheric profiling through release of dropsondes, and atmospheric attenuation calculated with the use of those data. Downward looking lidar data are also used to verify cloud and haze conditions during sampling. For HCR in CSET, eighteen usable ocean-scanning cases were found. Several of these were discarded due to cloud/haze issues that prevented accurate determination of atmospheric attenuation. Initial results show that a large (but fairly constant) bias

  6. Fire Data as Proxy for Anthropogenic Landscape Change in the Yucatán

    Directory of Open Access Journals (Sweden)

    Marco Millones

    2017-09-01

    Full Text Available Fire is one of the earliest and most common tools used by humans to modify the earth surface. Landscapes in the Yucatán Peninsula are composed of a mosaic of old growth subtropical forest, secondary vegetation, grasslands, and agricultural land that represent a well-documented example of anthropogenic intervention, much of which involves the use of fire. This research characterizes land use systems and land cover changes in the Yucatán during the 2000–2010 time period. We used an active fire remotely sensed data time series from the Moderate Resolution Imaging Spectroradiometer (MODIS, in combination with forest loss, and anthrome map sources to (1 establish the association between fire and land use change in the region; and (2 explore links between the spatial and temporal patterns of fire and specific types of land use practices, including within- and between-anthromes variability. A spatial multinomial logit model was constructed using fire, landscape configuration, and a set of commonly used control variables to estimate forest persistence, non-forest persistence, and change. Cross-tabulations and descriptive statistics were used to explore the relationships between fire occurrence, location, and timing with respect to the geography of land use. We also compared fire frequencies within and between anthrome groups using a negative binomial model and Tukey pairwise comparisons. Results show that fire data broadly reproduce the geography and timing of anthropogenic land change. Findings indicate that fire and landscape configuration is useful in explaining forest change and non-forest persistence, especially in fragmented (mosaicked landscapes. Absence of fire occurrence is related usefully to the persistence of spatially continuous core areas of older growth forest. Fire has a positive relationship with forest to non-forest change and a negative relationship with forest persistence. Fire is also a good indicator to distinguish between

  7. Legal disputes as a proxy for regional conflicts over water rights in Chile

    Science.gov (United States)

    Rivera, Diego; Godoy-Faúndez, Alex; Lillo, Mario; Alvez, Amaya; Delgado, Verónica; Gonzalo-Martín, Consuelo; Menasalvas, Ernestina; Costumero, Roberto; García-Pedrero, Ángel

    2016-04-01

    Water demand and climate variability increases competition and tension between water users -agricultural, industrial, mining, hydropower- and local communities. Since 1981, the Water Code has regulated water allocation through private individual property rights, fostering markets as the distribution mechanism among users. When legal conflicts occur between parties, it is the responsibility of the courts to settle the conflict. The aim of this research is twofold: first, to apply a geographical approach by mapping water conflicts using legal disputes reaching the higher courts as a proxy for conflict intensity and second, to explain the diversity of water disputes and how they vary regionally. We built a representative database with a sample of 1000 legal records corresponding to decisions issued by the Supreme Court and 17 courts of appeal throughout the country from 1981 to 2014. For geo-tagging, all records were transformed to plain text and analyzed to find words matching the entries of a geographical thesaurus, allowing records to be linked to geographical locations. The geo-tagging algorithm is capable of automatically populating a searchable database. Several maps were constructed using a color scale to visualize conflict intensity. Legal disputes represent different types of conflicts among water users, such as competition between agriculture and hydropower. Processed data allowed the identification of the regional variation of conflicts. The spatial pattern for the intensity of conflicts related to specific sections of the Water Code is explained in terms of the main geographical, climatic and productive characteristics of Chile. Geo-tagging legal records shows a strong potential to understand and define regional variation of water conflicts. However, data availability would become a barrier if measures to improve data management were not taken. Regarding the institutional framework, the same regulations for water management rules are applied throughout the

  8. Linking coral river runoff proxies with climate variability, hydrology and land-use in Madagascar catchments.

    Science.gov (United States)

    Maina, Joseph; de Moel, Hans; Vermaat, Jan E; Bruggemann, J Henrich; Guillaume, Mireille M M; Grove, Craig A; Madin, Joshua S; Mertz-Kraus, Regina; Zinke, Jens

    2012-10-01

    Understanding the linkages between coastal watersheds and adjacent coral reefs is expected to lead to better coral reef conservation strategies. Our study aims to examine the main predictors of environmental proxies recorded in near shore corals and therefore how linked near shore reefs are to the catchment physical processes. To achieve these, we developed models to simulate hydrology of two watersheds in Madagascar. We examined relationships between environmental proxies derived from massive Porites spp. coral cores (spectral luminescence and barium/calcium ratios), and corresponding time-series (1950-2006) data of hydrology, climate, land use and human population growth. Results suggest regional differences in the main environmental drivers of reef sedimentation: on annual time-scales, precipitation, river flow and sediment load explained the variability in coral proxies of river discharge for the northeast region, while El Niño-Southern Oscillation (ENSO) and temperature (air and sea surface) were the best predictors in the southwest region. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Exploring foraminiferal Sr/Ca as a new carbonate system proxy

    Science.gov (United States)

    Keul, Nina; Langer, Gerald; Thoms, Silke; de Nooijer, Lennart Jan; Reichart, Gert-Jan; Bijma, Jelle

    2017-04-01

    In present day paleoclimate research one of the most pressing challenges is the reconstruction of atmospheric CO2 concentrations. A variety of proxies for several components of the marine inorganic carbon system have been developed in this context (e.g. B isotopes, B/Ca, U/Ca) to allow reconstruction of past seawater pH, HCO3- and CO32- and thereby facilitate estimates of past atmospheric pCO2. Based on culture experiments using the benthic foraminifera Ammonia sp. we describe a positive correlation between Sr/Ca and the carbonate system, namely DIC/bicarbonate ion concentration. Foraminiferal Sr/Ca ratios provide potentially additional constraints on the carbonate system proxy, because the analysis of foraminiferal carbonate Sr/Ca is straightforward and not easily contaminated. Applying our calibration to a published dataset of paleo-Sr/Ca suggests the validity of Sr/Ca as a carbonate system proxy. Furthermore, we explore how our data can be used to advance conceptual understanding of the foraminiferal biomineralization mechanism.

  10. Biomarker Proxy Calibration Along the AMT Transect: Alkenone Uk37' and δD

    Science.gov (United States)

    Gould, J.; Kienast, M.; Dowd, M.; Schefuß, E.

    2016-12-01

    This study analyzes 60 suspended particulate organic matter (SPOM) samples from an Atlantic Meridional Transect (AMT20), spanning approximately 105° latitude (Southampton to Punta Arenas), for key biomarker proxy signatures: alkenone unsaturation (Uk37') and hydrogen isotopic (δD) composition. The wide range in surface ocean characteristics along the transect offers a unique opportunity to refine our understanding of these proxies. Initial alkenone δD values correlate - to a first order - with water column δD signatures, which in turn parallel salinity values along the AMT20 transect. Other factors that have been shown to influence δD will be discussed as well. The Uk37' data presented are in good agreement with previously published SPOM data, though we offer an alternative regression model to relate Uk37' to sea surface temperatures (SST); the Richards curve (Richards, 1959). This non-linear regression model uniquely accounts for both the fact that the Uk37' index is a proportion, and so must lie between 0 and 1, as well as for an apparent reduction in slope at temperature extremes. The inverse of this relationship allows estimation of SST from a measured Uk37' value with quantitative estimates of uncertainty. Further, we have identified a pronounced seasonal sampling bias in the SPOM dataset analyzed in this and prior studies (e.g. Conte et al. 2006), which may be contributing to a reported offset between surface particulate and core-top Uk37'- SST calibrations for this proxy.

  11. Technical Note: Correcting for signal attenuation from noisy proxy data in climate reconstructions

    Directory of Open Access Journals (Sweden)

    C. M. Ammann

    2010-04-01

    Full Text Available Regression-based climate reconstructions scale one or more noisy proxy records against a (generally short instrumental data series. Based on that relationship, the indirect information is then used to estimate that particular measure of climate back in time. A well-calibrated proxy record(s, if stationary in its relationship to the target, should faithfully preserve the mean amplitude of the climatic variable. However, it is well established in the statistical literature that traditional regression parameter estimation can lead to substantial amplitude attenuation if the predictors carry significant amounts of noise. This issue is known as "Measurement Error" (Fuller, 1987; Carroll et al., 2006. Climate proxies derived from tree-rings, ice cores, lake sediments, etc., are inherently noisy and thus all regression-based reconstructions could suffer from this problem. Some recent applications attempt to ward off amplitude attenuation, but implementations are often complex (Lee et al., 2008 or require additional information, e.g. from climate models (Hegerl et al., 2006, 2007. Here we explain the cause of the problem and propose an easy, generally applicable, data-driven strategy to effectively correct for attenuation (Fuller, 1987; Carroll et al., 2006, even at annual resolution. The impact is illustrated in the context of a Northern Hemisphere mean temperature reconstruction. An inescapable trade-off for achieving an unbiased reconstruction is an increase in variance, but for many climate applications the change in mean is a core interest.

  12. Understanding the milk-to-feed price ratio as a proxy for dairy farm profitability.

    Science.gov (United States)

    Wolf, C A

    2010-10-01

    This research examines the definition, historical pattern, and utility of the milk-to-feed price ratio (MF) as a measure of dairy farm profitability. The MF was generally an acceptable proxy of profitability in an annual sense from 1985 to 2006. The MF was steady at an average of 2.8 from 1985 to 2006 even as average annual milk price in nominal terms increased from $12 to $14/hundredweight. An alternative proxy for profitability is income over feed costs, which is measured in dollars per hundredweight. Comparison with an actual profit measure, rate of return on assets, is used to examine the appropriateness of the proxies. The volatility from 2007 to 2009 resulted in MF being a poor measure of profitability over that period. The implication is that MF is not the preferred measure of profitability when a significant change in the pattern of one or both price series occurs. Income over feed cost is a better measure of profitability in periods of volatility. Copyright © 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. A provably secure identity-based strong designated verifier proxy signature scheme from bilinear pairings

    Directory of Open Access Journals (Sweden)

    SK Hafizul Islam

    2014-01-01

    Full Text Available The proxy signature, a variant of the ordinary digital signature, has been an active research topic in recent years; it has many useful applications, including distributed systems and grid computing. Although many identity-based proxy signature schemes have been proposed in the literature, only a few proposals for identity-based strong designated verifier proxy signature (ID-SDVPS schemes are available. However, it has been found that most of the ID-SDVPS schemes that have been proposed to date are not efficient in terms of computation and security, and a computationally efficient and secured ID-SDVPS scheme using elliptic curve bilinear pairing has been proposed in this paper. The security of the scheme is mainly based on the hardness assumption of CDH and GBDH problems in the random oracle model, which is existentially unforgeable against different types of adversaries. Furthermore, the security of our scheme is simulated in the AVISPA (Automated Validation of Internet Security Protocols and Applications software, a widely used automated internet protocol validation tool, and the simulation results confirm strong security against both active and passive attacks. In addition, because of a high processing capability and supporting additional security features, the scheme is suitable for the environments in which less computational cost with strong security is required.

  14. [A case of Munchausen Syndrome by proxy in the context of folie a famille].

    Science.gov (United States)

    Foto Özdemir, Dilşad; Gökler, Bahar; Evinç, Ş Gülin; Balseven Odabaşı, Aysun

    2013-01-01

    The occurrence of similar psychotic symptoms in two or more people is called shared paranoid disorder. In this disease, the person who exhibits psychotic symptoms first is the "primary patient". The symptoms are contracted by the other people through persuasion. This disorder is seen among people who share the same house or are emotionally bound. In some cases, shared paranoid disorder may include other diagnoses, such as Munchausen Syndrome. This report discusses the case of a six-year-old, sexually abused boy who, when admitted to the hospital at the age of 10, claimed to have been repeatedly sexually harassed by several different people. His family's frequent changes in hospitals, negative perceptions of and accusations against medical staff, and improper methods of responding to harassment led clinicians to a diagnosis of Munchausen by proxy syndrome. In addition, both parents believed the abuse story, suggesting a potential diagnosis of shared psychotic disorder. In the literature, Munchausen by proxy has rarely been reported with symptoms of sexual abuse. The psychotic symptoms were shared by the family, complicating the case. This report emphasizes that psychodynamic evaluations of Munchausen by proxy and shared psychotic disorder may be helpful in understanding underlying factors.

  15. Comparing Sunspot Area and Sunspot Number as Proxies for Long-term Solar Irradiance Variation

    Science.gov (United States)

    Jordan, Stuart D.; Garcia, A. G.; Oegerle, William (Technical Monitor)

    2002-01-01

    Because relevant observations from space began only in 1979 with Nimbus-7, it is impossible to correlate direct measurements of small changes in solar irradiance with terrestrial temperature over a number of solar cycles. Yet there is recent evidence that some feature of solar change over a cycle may have a larger influence on climate than would result from merely introducing the additional amount of heat delivered to Earth's atmosphere at solar minimum. It would be useful to check this possibility over several solar cycles. To do this, we would need a sufficiently reliable proxy for irradiance change that at least survives a test against the space observations. Sunspot area is a fairly straightforward parameter to measure, and is associated with the extent of magnetic activity known to correlate strongly with solar irradiance change. We have tested the use of sunspot area as a long-term proxy for solar irradiance change, using observations made at the Coimbra Solar Observatory, from which we obtain both statistically weighted sunspot numbers and sunspot areas over the period 1980-1992. These are both correlated with solar irradiance values measured from Nimbus-7 spacecraft over the same time period, to see if sunspot area offers affords a strong positive correlation and also a distinct advantage over sunspot number as a useful proxy that can then be compared with terrestrial temperature records. Preliminary results yield a positive correlation of 0.71 for sunspot area, but further tests are being conducted and will be reported.

  16. Bivariate spatial analysis of temperature and precipitation from general circulation models and observation proxies

    KAUST Repository

    Philbin, R.

    2015-05-22

    This study validates the near-surface temperature and precipitation output from decadal runs of eight atmospheric ocean general circulation models (AOGCMs) against observational proxy data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis temperatures and Global Precipitation Climatology Project (GPCP) precipitation data. We model the joint distribution of these two fields with a parsimonious bivariate Matérn spatial covariance model, accounting for the two fields\\' spatial cross-correlation as well as their own smoothnesses. We fit output from each AOGCM (30-year seasonal averages from 1981 to 2010) to a statistical model on each of 21 land regions. Both variance and smoothness values agree for both fields over all latitude bands except southern mid-latitudes. Our results imply that temperature fields have smaller smoothness coefficients than precipitation fields, while both have decreasing smoothness coefficients with increasing latitude. Models predict fields with smaller smoothness coefficients than observational proxy data for the tropics. The estimated spatial cross-correlations of these two fields, however, are quite different for most GCMs in mid-latitudes. Model correlation estimates agree well with those for observational proxy data for Australia, at high northern latitudes across North America, Europe and Asia, as well as across the Sahara, India, and Southeast Asia, but elsewhere, little consistent agreement exists.

  17. Polar Network Index as a Magnetic Proxy for the Solar Cycle Studies

    Science.gov (United States)

    Priyal, Muthu; Banerjee, Dipankar; Karak, Bidya Binay; Muñoz-Jaramillo, Andrés; Ravindra, B.; Choudhuri, Arnab Rai; Singh, Jagdev

    2014-09-01

    The Sun has a polar magnetic field which oscillates with the 11 yr sunspot cycle. This polar magnetic field is an important component of the dynamo process which operates in the solar convection zone and produces the sunspot cycle. We have direct systematic measurements of the Sun's polar magnetic field only from about the mid-1970s. There are, however, indirect proxies which give us information about this field at earlier times. The Ca-K spectroheliograms taken at the Kodaikanal Solar Observatory during 1904-2007 have now been digitized with 4k × 4k CCD and have higher resolution (~0.86 arcsec) than the other available historical data sets. From these Ca-K spectroheliograms, we have developed a completely new proxy (polar network index, hereafter PNI) for the Sun's polar magnetic field. We calculate PNI from the digitized images using an automated algorithm and calibrate our measured PNI against the polar field as measured by the Wilcox Solar Observatory for the period 1976-1990. This calibration allows us to estimate the polar fields for the earlier period up to 1904. The dynamo calculations performed with this proxy as input data reproduce reasonably well the Sun's magnetic behavior for the past century.

  18. Design and implementation of Ad-Hoc collaborative proxying scheme for reducing network energy waste

    Directory of Open Access Journals (Sweden)

    Rafiullah Khan

    2017-05-01

    Full Text Available Network devices are equipped with low power states but they are rarely activated due to their inability of maintaining network connectivity. Recently, Network Connectivity Proxy (NCP concept has been proposed in literature as an effective mechanism to exploit full potential of low power features on network devices by impersonating their virtual presence. However, the NCP concept faces several open issues and challenges especially related to proxying of TCP connections and majority of daily used proprietary closed-source applications. This paper presents a new approach for reducing network energy waste through intelligent collaboration among daily used devices (e.g., desktop computers, laptops, tablets, smartphones, etc. It guarantees to run applications on only and only one user device that is under active use at that specific moment. To reduce energy waste and allow idle devices to sleep, our approach also takes benefit from a light-weight home gateway proxy with very basic practically realizable functionalities. The proposed system not just reduces energy waste of fixed devices but also enables mobile devices to significantly improve their battery life. Our developed software prototypes allow devices to autonomously and seamlessly collaborate with each other without requiring any configuration or user input. Further, this paper also presents the basic performance evaluation of developed prototypes in real networking environments.

  19. Technical Note: Correcting for signal attenuation from noisy proxy data in climate reconstructions

    KAUST Repository

    Ammann, C. M.

    2010-04-20

    Regression-based climate reconstructions scale one or more noisy proxy records against a (generally) short instrumental data series. Based on that relationship, the indirect information is then used to estimate that particular measure of climate back in time. A well-calibrated proxy record(s), if stationary in its relationship to the target, should faithfully preserve the mean amplitude of the climatic variable. However, it is well established in the statistical literature that traditional regression parameter estimation can lead to substantial amplitude attenuation if the predictors carry significant amounts of noise. This issue is known as "Measurement Error" (Fuller, 1987; Carroll et al., 2006). Climate proxies derived from tree-rings, ice cores, lake sediments, etc., are inherently noisy and thus all regression-based reconstructions could suffer from this problem. Some recent applications attempt to ward off amplitude attenuation, but implementations are often complex (Lee et al., 2008) or require additional information, e.g. from climate models (Hegerl et al., 2006, 2007). Here we explain the cause of the problem and propose an easy, generally applicable, data-driven strategy to effectively correct for attenuation (Fuller, 1987; Carroll et al., 2006), even at annual resolution. The impact is illustrated in the context of a Northern Hemisphere mean temperature reconstruction. An inescapable trade-off for achieving an unbiased reconstruction is an increase in variance, but for many climate applications the change in mean is a core interest.

  20. Hospital stay as a proxy indicator for severe injury in earthquakes: a retrospective analysis.

    Science.gov (United States)

    Zhao, Lu-Ping; Gerdin, Martin; Westman, Lina; Rodriguez-Llanes, Jose Manuel; Wu, Qi; van den Oever, Barbara; Pan, Liang; Albela, Manuel; Chen, Gao; Zhang, De-Sheng; Guha-Sapir, Debarati; von Schreeb, Johan

    2013-01-01

    Earthquakes are the most violent type of natural disasters and injuries are the dominant medical problem in the early phases after earthquakes. However, likely because of poor data availability, high-quality research on injuries after earthquakes is lacking. Length of hospital stay (LOS) has been validated as a proxy indicator for injury severity in high-income settings and could potentially be used in retrospective research of injuries after earthquakes. In this study, we assessed LOS as an adequate proxy indicator for severe injury in trauma survivors of an earthquake. A retrospective analysis was conducted using a database of 1,878 injured patients from the 2008 Wenchuan earthquake. Our primary outcome was severe injury, defined as a composite measure of serious injury or resource use. Secondary outcomes were serious injury and resource use, analysed separately. Non-parametric receiver operating characteristics (ROC) and area under the curve (AUC) analysis was used to test the discriminatory accuracy of LOS when used to identify severe injury. An 0.7earthquake survivors. However, LOS was found to be a proxy for major nonorthopaedic surgery and blood transfusion. These findings can be useful for retrospective research on earthquake-injured patients when detailed hospital records are not available.

  1. The Last Interglacial-Glacial cycle (MIS 5-2) re-examined based on long proxy records from central and northern Europe

    Science.gov (United States)

    Helmens, Karin F.

    2014-02-01

    Current multi-proxy studies on a long sediment sequence preserved at Sokli (N Finland), i.e. in the central area of Fennoscandian glaciations, are drastically changing classic ideas of glaciations, vegetation and climate in northern Europe during the Late Pleistocene. The sediments in the Sokli basin have escaped major glacial erosion due to non-typical bedrock conditions. In this review, the Sokli record is compared in great detail with other long proxy records from central, temperate and northern, boreal Europe. These comprise the classic records of La Grande Pile (E France) and Oerel (N Germany) and more recently obtained records from Horoszki Duże (E Poland) and Lake Yamozero (NW Russia). The focus of the review is on pollen, lithology and macrofossil- and insect-based temperature inferences. The long records are further compared with recent proxy data from nearby terrestrial sites as well as with the rapidly accumulating high-resolution proxy data from the ocean realm. The comparison allows a re-examination of the environmental history and climate evolution of the Last Interglacial-Glacial (LI-G) cycle (MIS 5-2). It shows that environmental and climate conditions during MIS 5 (ca 130-70 ka BP) were distinctly different from those during MIS 4-2 (ca 70-15 ka BP). MIS 5 is characterized by three long forested intervals (broadly corresponding to MIS 5e, 5c, 5a), both in temperate and northern boreal Europe. These mild periods were interrupted by two short, relatively cold and dry intervals (MIS 5d and 5b) with mountain-centered glaciation in Fennoscandia. Millennial scale climate events were superimposed upon these longer lasting climate fluctuations. The time interval encompassing MIS 4-2 shows open vegetation. It is characterized by two glacial maxima (MIS 4 and 2) with sub-continental scale glaciation over northern Europe and dry conditions in strongly continental eastern European settings. High amplitude climate oscillations of millennial duration

  2. Core-top calibration of B/Ca in Pacific Ocean Neogloboquadrina incompta and Globigerina bulloides as a surface water carbonate system proxy

    Science.gov (United States)

    Quintana Krupinski, Nadine B.; Russell, Ann D.; Pak, Dorothy K.; Paytan, Adina

    2017-05-01

    Practical methods for reconstructing past ocean carbonate chemistry are needed to study past periods of ocean acidification and improve understanding of the marine carbonate system's role in the global climate cycles. Planktic foraminiferal B/Ca may fill this role, but requires better understanding and improved proxy calibrations. We used Pacific Ocean core-top sediments to generate new calibrations of the B/Ca proxy for past carbonate system parameters in two upwelling/subpolar species of asymbiotic planktic foraminifera (Globigerina bulloides and Neogloboquadrina incompta). Both species show significant positive correlation of B/Ca with calcite saturation (Ωcalcite) and carbonate ion concentration ([3 2-CO]) across a broad range of environmental conditions. This suggests a calcification rate control on B/Ca incorporation (as Ωcalcite regulates calcification rate), in agreement with recent inorganic calcite studies. This is also consistent with a surface entrapment model of trace element incorporation into CaCO3. In neither species is B/Ca significantly correlated with pH, suggesting that pH does not directly regulate boron incorporation, and that calculation of pH directly from foraminiferal B/Ca is not suitable. Correlations between B/Ca and [B(OH)4-], [B(OH)4-/HCO3-], and [B(OH)4-]/DIC) are weaker than with Ωcalcite. Boron partition coefficients (KD =[ B / Ca ] solid /[ B4 -(OH) /HCO-3 ] seawater) show little or no correlation with [CO32-] or temperature and vary widely, providing no support for application of KD to calculate carbonate system parameters from B/Ca. We also discuss potential effects of depth-related dissolution, temperature, and salinity on B/Ca. These empirical calibrations linking foraminiferal calcite B/Ca with Ωcalcite provide a strong tool for reconstructing the past ocean carbonate system and improve our understanding of the proxy's geochemical basis.

  3. El Niño impact on mollusk biomineralization-implications for trace element proxy reconstructions and the paleo-archeological record.

    Directory of Open Access Journals (Sweden)

    Alberto Pérez-Huerta

    Full Text Available Marine macroinvertebrates are ideal sentinel organisms to monitor rapid environmental changes associated with climatic phenomena. These organisms build up protective exoskeletons incrementally by biologically-controlled mineralization, which is deeply rooted in long-term evolutionary processes. Recent studies relating potential rapid environmental fluctuations to climate change, such as ocean acidification, suggest modifications on carbonate biominerals of marine invertebrates. However, the influence of known, and recurrent, climatic events on these biological processes during active mineralization is still insufficiently understood. Analysis of Peruvian cockles from the 1982-83 large magnitude El Niño event shows significant alterations of the chemico-structure of carbonate biominerals. Here, we show that bivalves modify the main biomineralization mechanism during the event to continue shell secretion. As a result, magnesium content increases to stabilize amorphous calcium carbonate (ACC, inducing a rise in Mg/Ca unrelated to the associated increase in sea-surface temperature. Analysis of variations in Sr/Ca also suggests that this proxy should not be used in these bivalves to detect the temperature anomaly, while Ba/Ca peaks are recorded in shells in response to an increase in productivity, or dissolved barium in seawater, after the event. Presented data contribute to a better understanding of the effects of abrupt climate change on shell biomineralization, while also offering an alternative view of bivalve elemental proxy reconstructions. Furthermore, biomineralization changes in mollusk shells can be used as a novel potential proxy to provide a more nuanced historical record of El Niño and similar rapid environmental change events.

  4. Fractionation behavior of chromium isotopes during coprecipitation with calcium carbonate: Implications for their use as paleoclimatic proxy

    Science.gov (United States)

    Rodler, A.; Sánchez-Pastor, N.; Fernández-Díaz, L.; Frei, R.

    2015-09-01

    Interest in chromium (Cr) isotope incorporation into carbonates arises from the observation that Cr isotopic composition of carbonates could be used as a paleoclimate proxy to elucidate past fluctuations of oxygen contents in atmosphere and hydrosphere. The use of Cr isotopes to track paleoenvironmental changes, for example related to the rise of oxygen during the Archaean and Protoerozoic, needs careful assessment of the signal robustness and necessitates a thorough understanding of the Cr cycle in Earth system processes. We conducted experiments testing the incorporation of chromate into the calcite lattice to investigate isotopic changes facilitated by the coprecipitation process. Our experiments indicate enrichment in Cr concentration in the precipitates compared to the solutions, consistent with previous reports of Cr enrichment in chemical sediments compared to ambient seawater. The fractionation of Cr isotopes during calcium carbonate coprecipitation was assumed to be small, based on previously published data of modern seawater and modern non-skeletal marine carbonates. However, results from this study for rapidly precipitated calcium carbonate in the presence of chromate show a tendency for preferential incorporation of heavy Cr isotopes in the precipitates resulting in increasing relative isotope difference between precipitate and initial solution (Δ53Cr[p-is]) from +0.06‰ to +0.18‰, with increasing initial Cr concentration of the solution. Sample precipitation in the presence of chromate also showed the presence of vaterite. Calcium carbonate crystals were also precipitated in a double diffusion silica hydrogel over a longer period of time resulting in samples consisting of micrometric-millimetric calcite crystals, which were again significantly enriched in heavy Cr isotopes compared to the initial solutions. They average, irrespective of the initial Cr concentration, a relative isotope difference (Δ53Cr[p-is]) of +0.29 ± 0.08‰ (2σ), whereas

  5. European Neolithic societies showed early warning signals of population collapse.

    Science.gov (United States)

    Downey, Sean S; Haas, W Randall; Shennan, Stephen J

    2016-08-30

    Ecosystems on the verge of major reorganization-regime shift-may exhibit declining resilience, which can be detected using a collection of generic statistical tests known as early warning signals (EWSs). This study explores whether EWSs anticipated human population collapse during the European Neolithic. It analyzes recent reconstructions of European Neolithic (8-4 kya) population trends that reveal regime shifts from a period of rapid growth following the introduction of agriculture to a period of instability and collapse. We find statistical support for EWSs in advance of population collapse. Seven of nine regional datasets exhibit increasing autocorrelation and variance leading up to collapse, suggesting that these societies began to recover from perturbation more slowly as resilience declined. We derive EWS statistics from a prehistoric population proxy based on summed archaeological radiocarbon date probability densities. We use simulation to validate our methods and show that sampling biases, atmospheric effects, radiocarbon calibration error, and taphonomic processes are unlikely to explain the observed EWS patterns. The implications of these results for understanding the dynamics of Neolithic ecosystems are discussed, and we present a general framework for analyzing societal regime shifts using EWS at large spatial and temporal scales. We suggest that our findings are consistent with an adaptive cycling model that highlights both the vulnerability and resilience of early European populations. We close by discussing the implications of the detection of EWS in human systems for archaeology and sustainability science.

  6. Clay minerals as palaeomonsoon proxies: Evaluation and relevance to the late Quaternary records from SE Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Thamban, M.; Rao, V.P.

    Palaeoclimatic studies are largely dependent on the quality of records and a prudent use of environmental proxy indicators. In this study, the factors affecting the detrital clay minerals in marine environment and their utility and reliability...

  7. Servidor proxy caché: comprensión y asimilación tecnológica

    Directory of Open Access Journals (Sweden)

    Carlos E. Gómez

    2012-01-01

    Full Text Available Los proveedores de acceso a Internet usualmente incluyen el concepto de aceleradores de Internet para reducir el tiempo promedio que tarda un navegador en obtener los archivos solicitados. Para los administradores del sistema es difícil elegir la configuración del servidor proxy caché, ya que es necesario decidir los valores que se deben usar en diferentes variables. En este artículo se presenta la forma como se abordó el proceso de comprensión y asimilación tecnológica del servicio de proxy caché, un servicio de alto impacto organizacional. Además, este artículo es producto del proyecto de investigación “Análisis de configuraciones de servidores proxy caché”, en el cual se estudiaron aspectos relevantes del rendimiento de Squid como servidor proxy caché.

  8. Interrelations between Three Proxies of Health Care Need at the Small Area Level: An Urban/Rural Comparison

    National Research Council Canada - National Science Library

    S. Barnett; P. Roderick; D. Martin; I. Diamond; H. Wrigley

    2002-01-01

    ...) and socioeconomic characteristics, and 1991-1996 data on all cause premature mortality. The interrelations between the three widely used proxies of health care need are examined using correlation coefficients and scatterplots...

  9. Simple proxies for estimating the concentrations of monoterpenes and their oxidation products at a boreal forest site

    Directory of Open Access Journals (Sweden)

    J. Kontkanen

    2016-10-01

    Full Text Available The oxidation products of monoterpenes likely have a crucial role in the formation and growth of aerosol particles in boreal forests. However, the continuous measurements of monoterpene concentrations are usually not available on decadal timescales, and the direct measurements of the concentrations of monoterpene oxidation product have so far been scarce. In this study we developed proxies for the concentrations of monoterpenes and their oxidation products at a boreal forest site in Hyytiälä, southern Finland. For deriving the proxies we used the monoterpene concentration measured with a proton transfer reaction mass spectrometer (PTR-MS during 2006–2013. Our proxies for the monoterpene concentration take into account the temperature-controlled emissions from the forest ecosystem, the dilution caused by the mixing within the boundary layer and different oxidation processes. All the versions of our proxies captured the seasonal variation of the monoterpene concentration, the typical proxy-to-measurements ratios being between 0.8 and 1.3 in summer and between 0.6 and 2.6 in winter. In addition, the proxies were able to describe the diurnal variation of the monoterpene concentration rather well, especially in summer months. By utilizing one of the proxies, we calculated the concentration of oxidation products of monoterpenes by considering their production in the oxidation and their loss due to condensation on aerosol particles. The concentration of oxidation products was found to have a clear seasonal cycle, with a maximum in summer and a minimum in winter. The concentration of oxidation products was lowest in the morning or around noon and highest in the evening. In the future, our proxies for the monoterpene concentration and their oxidation products can be used, for example, in the analysis of new particle formation and growth in boreal environments.

  10. Experimental investigation of the degassing behavior of Hg via proxy heavy metals in natural and synthetic silicate melts

    Science.gov (United States)

    Johnson, A. D.; Canil, D.

    2009-12-01

    The degassing behavior of Bi, Tl, Au, Cd and Pb from silicate liquids have been investigated at 0.1 MPa. These metals were chosen on the basis that they may be used as a proxy for Hg. Natural basalt, dacite, and synthetic rhyolite (Ab-Or-Qz minimum eutectic) were doped with a heavy metal cocktail (Bi, Pb, Tl, Au, Re, Sb, Sn, In, Cd, Mo, As, Cu) and diffusion experiments were conducted in air at 0.1 MPa between 1200 - 1450 °C in open Pt capsules. Trace element concentration gradients for Bi, Tl, Au, Cd and Pb were measured normal to the polished melt(glass)/gas interface by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) after the experiment. Diffusion coefficients (Dx) were extracted for elements using a semi-infinite one-dimensional diffusion model. The effects of ligands on diffusivity were measured by adding Cl or S to experimental runs. Results show Au and Tl (which bracket Hg in the periodic table) are the most volatile in dacite at 1260°C (logDAu = -10.66 ± 0.20 m2/s and logDTl = -11.03 ± 0.15 m2/s ) followed by Cd, Pb and Bi (logDCd = -11.58 ± 0.07 m2/s, logDPb = -11.77 ± 0.2 m2/s, logDBi = -12.11 ± 0.2 m2/s;). The effect of starting composition on metal diffusion shows the diffusivity of Tl at 1260°C decreases from logDTl = -10.84 ± 0.22 m2/s in basalt to logDTl = -11.03 ± 0.15 m2/s and logDTl = -11.60 ± 0.20 m2/s in dacite and synthetic Ab-Or-Qz respectively. Decreasing diffusivity would be expected with increasing silica content that inhibits diffusion. We apply our diffusivities in a 1-D bubble growth model to observe differences in metal ratios in gas bubbles that would form in volcanic plumes. In this way, we see the changing heavy metal ratios in the gas phase may be useful in eruption prediction. This work may also help better constrain the behavior/mobility of Hg (using these metals as a proxy) in nature and its loading effect from volcanoes on the atmosphere and biosphere.

  11. He said, she said: The gender wage gap according to self and proxy reports in the Current Population Survey.

    Science.gov (United States)

    Reynolds, Jeremy; Wenger, Jeffrey B

    2012-03-01

    Roughly half the labor force data in the Current Population Survey (CPS) are provided by proxy respondents, and since 1979, men's reliance on proxies has dropped dramatically while women's reliance on proxies has increased. Few authors, however, have examined how combining these first-hand and second-hand reports may influence our understanding of long-term economic trends. We exploit the outgoing rotation group structure of the CPS by matching individual records one year apart, and we find that self-reported wages are higher than proxy-reported wages even after controlling for all time invariant characteristics. Furthermore, we find that changes in the use of proxy respondents by men and women since 1979 have made current estimates of the gender wage gap larger than they would have been without changes in reporting status. This suggests that the gender wage gap has closed more than previously estimated. We recommend that researchers combine self and proxy responses with great care, especially when analyzing time trends or making gender comparisons. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Sensor Proxy Mobile IPv6 (SPMIPv6—A Novel Scheme for Mobility Supported IP-WSNs

    Directory of Open Access Journals (Sweden)

    Md. Motaharul Islam

    2011-02-01

    Full Text Available IP based Wireless Sensor Networks (IP-WSNs are gaining importance for their broad range of applications in health-care, home automation, environmental monitoring, industrial control, vehicle telematics and agricultural monitoring. In all these applications, mobility in the sensor network with special attention to energy efficiency is a major issue to be addressed. Host-based mobility management protocols are not suitable for IP-WSNs because of their energy inefficiency, so network based mobility management protocols can be an alternative for the mobility supported IP-WSNs. In this paper we propose a network based mobility supported IP-WSN protocol called Sensor Proxy Mobile IPv6 (SPMIPv6. We present its architecture, message formats and also evaluate its performance considering signaling cost, mobility cost and energy consumption. Our analysis shows that with respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 60% and 56%, as well as the mobility cost by 62% and 57%, compared to MIPv6 and PMIPv6, respectively. The simulation results also show that in terms of the number of hops, SPMIPv6 decreases the signaling cost by 56% and 53% as well as mobility cost by 60% and 67% as compared to MIPv6 and PMIPv6 respectively. It also indicates that proposed scheme reduces the level of energy consumption significantly.

  13. Sensor Proxy Mobile IPv6 (SPMIPv6)—A Novel Scheme for Mobility Supported IP-WSNs

    Science.gov (United States)

    Islam, Md. Motaharul; Huh, Eui-Nam

    2011-01-01

    IP based Wireless Sensor Networks (IP-WSNs) are gaining importance for their broad range of applications in health-care, home automation, environmental monitoring, industrial control, vehicle telematics and agricultural monitoring. In all these applications, mobility in the sensor network with special attention to energy efficiency is a major issue to be addressed. Host-based mobility management protocols are not suitable for IP-WSNs because of their energy inefficiency, so network based mobility management protocols can be an alternative for the mobility supported IP-WSNs. In this paper we propose a network based mobility supported IP-WSN protocol called Sensor Proxy Mobile IPv6 (SPMIPv6). We present its architecture, message formats and also evaluate its performance considering signaling cost, mobility cost and energy consumption. Our analysis shows that with respect to the number of IP-WSN nodes, the proposed scheme reduces the signaling cost by 60% and 56%, as well as the mobility cost by 62% and 57%, compared to MIPv6 and PMIPv6, respectively. The simulation results also show that in terms of the number of hops, SPMIPv6 decreases the signaling cost by 56% and 53% as well as mobility cost by 60% and 67% as compared to MIPv6 and PMIPv6 respectively. It also indicates that proposed scheme reduces the level of energy consumption significantly. PMID:22319386

  14. Fish species and community distributions as proxies for sea-floor habitat distributions: the Stellwagen Bank National Marine Sanctuary example (northwest Atlantic, Gulf Of Maine)

    Science.gov (United States)

    Auster, Peter J.; Joy, Kevin; Valentine, Page C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  15. Fish species and community distributions as proxies for seafloor habitat distributions: The Stellwagen Bank National Marine Sanctuary example (Northwest Atlantic, Gulf of Maine)

    Science.gov (United States)

    Auster, P.J.; Joy, K.; Valentine, P.C.

    2001-01-01

    Defining the habitats of fishes and associated fauna on outer continental shelves is problematic given the paucity of data on the actual types and distributions of seafloor habitats. However many regions have good data on the distributions of fishes from resource surveys or catch statistics because of the economic importance of the fisheries. Fish distribution data (species or communities) have been used as a proxy for the distribution of habitats to develop precautionary conservation strategies for habitat protection (e.g., marine protected areas, fishing gear restrictions). In this study we assessed the relationships between the distributions of fish communities and species derived from trawl survey data with the spatial distribution of sediment types determined by sampling and acoustic reflectance derived from multibeam sonar surveys in Stellwagen Bank National Marine Sanctuary. Fish communities were correlated with reflectance values but all communities did not occur in unique sediment types. This suggests that use of community distributions as proxies for habitats should include the caveat that a greater number of communities within an area could indicate a greater range of habitat types. Single species distributions showed relationships between abundance and reflectance values. Trawl catches with low abundances had wide variations in reflectance values while those with high abundances had narrower ranges indicating habitat affinities. Significant non-random frequency-dependent relationships were observed for 17 of 20 species although only 12 of 20 species had significant relationships based on rank correlation. These results suggest that species distributions based on trawl survey data can be used as proxies for the distribution of seafloor habitats. Species with known habitat associations can be used to infer habitat requirements of co-occurring species and can be used to identify a range of habitat types.

  16. Improved end-member characterization of modern organic matter pools in the Ohrid Basin (Albania, Macedonia) and evaluation of new palaeoenvironmental proxies

    Science.gov (United States)

    Holtvoeth, J.; Rushworth, D.; Imeri, A.; Cara, M.; Vogel, H.; Wagner, T.; Wolff, G. A.

    2015-08-01

    We present elemental, lipid biomarker and compound-specific isotope (δ13C, δ2H) data for soils and leaf litter collected in the catchment of Lake Ohrid (Albania, Macedonia), as well as macrophytes, particulate organic matter and sediments from the lake itself. Lake Ohrid provides an outstanding archive of continental environmental change of at least 1.2 M years and the purpose of our study is to ground truth organic geochemical proxies that we developed in order to study past changes in the terrestrial biome. We show that soils dominate the lipid signal of the lake sediments rather than the vegetation or aquatic biomass, while compound-specific isotopes (δ13C, δ2H) determined for n-alkanoic acids confirm a dominant terrestrial source of organic matter to the lake. There is a strong imprint of suberin monomers on the composition of total lipid extracts and chain-length distributions of n-alkanoic acids, n-alcohols, ω-hydroxy acids and α,ω-dicarboxylic acids. Our end-member survey identifies that ratios of mid-chain length suberin-derived to long-chain length cuticular-derived alkyl compounds as well as their average chain length distributions can be used as new molecular proxies of organic matter sources to the lake. We tested these for the 8.2 ka event, a pronounced and widespread Holocene climate fluctuation. In SE Europe climate became drier and cooler in response to the event, as is clearly recognizable in the carbonate and organic carbon records of Lake Ohrid sediments. Our new proxies indicate biome modification in response to hydrological changes, identifying two phases of increased soil OM supply, first from topsoils and then from mineral soils. Our study demonstrates that geochemical fingerprinting of terrestrial OM should focus on the main lipid sources, rather than the living biomass. Both can exhibit climate-controlled variability, but are generally not identical.

  17. Stalagmite high resolution local paleoclimatic proxies for Late Holocene in Mesoamerica: Exploring role of moisture upon the development of Mesoamerican cultures.

    Science.gov (United States)

    Martínez Izquierdo, H. B.; Bernal, J. P.; Pérez Enriquez, R.; Böhnel, H.; Morales-Malacara, J. B.; Solari, L.; Gómez-Tuena, A.

    2010-03-01

    The relationship between climate change and culture development in Mesoamerica is complex to unravel since many written archives were destroyed during natural disasters and cultural conflicts such as Spanish conquest. Local paleoclimate records offer a way to reconstruct this relationship. Stalagmites are amongst the most reliable records of past climate variability, due to their evolution in closed-system conditions, ease of dating, and inclusion of several geochemical proxies (such as calcite oxygen and carbon isotopic composition, trace element concentration and/or elemental ratios, color and grey-tone scale). Recently, stalagmites have been used as records to explore the climatic change during Holocene and its cultural relation in Mediterranean, Asian, North American and east African cultures. Only few works were made, however, for Mesoamerican cultures. We study here a banded stalagmite belonging to Jalpan, Queretaro, central Mexico. This stalagmite was found actively growing, with its base dated at 6.85 +/- 0.3 Ka B.P. A high resolution LA-ICP-MS Mg/Ca analysis as well as grey tone analysis were obtained in order to create annual resolution time series. The proxies were correlated with local and north Atlantic paleoclimate records. Such proxies also show signals associated with volcanic eruptions (Tacana, el Chichon, Popocatepetl and Ceboruco) during the Classic period. Other signals are associated with Maya civilization collapse. These results portray the relationship between the agricultural and population patterns with moisture variability for the center of Mexico (Teotihuacan influence zone) during late Formative and Classic period. Finally, we observe patterns such as the corresponding to the little ice age and the anthropogenic climate warming, the latter correlated with local precipitation data.

  18. Parent-proxy perception of overweight adolescents' health-related quality of life is different according to adolescent gender and age and parent gender.

    Science.gov (United States)

    Bianchini, Josiane Aparecida Alves; da Silva, Danilo Fernandes; Nardo, Claudia Christina Sanchez; Carolino, Idalina Diair Regla; Hernandes, Florencio; Nardo, Nelson

    2013-10-01

    This study assessed health-related quality of life (HRQoL) reported by overweight adolescents and compared to their parent-proxy perception of HRQoL, according to adolescent gender, adolescent age, and parent gender. Patients and a total of 179 adolescents aged 10 to 18 years with excess weight were evaluated for perceived HRQoL prior to beginning a weight-loss intervention, using the Pediatric Quality of Life Inventory (PedsQL 4.0) questionnaire, estimating quality of life in the physical, emotional, social, and school domains, as well as index measures of psychosocial and overall quality of life. Parents completed the same questionnaire estimating his or her child's HRQoL. Compared to their child's self-report, parents underestimated all the domains of HRQoL except the school domain. Parents underestimated all the domains of HRQoL among boys; however, they only underestimated the physical domain among girls. Comparisons between parent-proxy perception and self-report of the adolescent according to adolescent's age revealed that parents underestimated their children's HRQoL in the younger adolescents (10 to 13 years) for all except for the school domain and underestimated only the physical domain in older adolescents (14 to 18 years). The same comparison between parent-proxy perception and their child's self-report of HRQoL according to parent gender showed that mothers underestimated HRQoL in all domains except for the school domain, while fathers only underestimated the school domain. The differences between self-report of overweight adolescent and perceptions of their parents about the HRQoL of their children are influenced by adolescent gender and age and parent gender.

  19. Calcareous nannofossil paleofluxes as proxy for pCO2 during the Aptian

    Science.gov (United States)

    Bottini, Cinzia; Erba, Elisabetta; Tiraboschi, Daniele

    2014-05-01

    The Aptian (~121 to ~113 Ma) has been characterized by super-greenhouse climate and profound environmental perturbations, including the early Aptian Oceanic Anoxic Event (OAE 1) a, an episode of widespread organic matter burial in oxygen-depleted oceans. The OAE 1a is thought to be related to the emplacement of the Ontong Java Plateau which probably introduced in the atmosphere a large amount of CO2 with consequent impact on biota, climate and ocean chemistry. The major perturbation of the carbon cycle is mirrored by the carbon isotopic record which shows a negative shift at the beginning of OAE 1a followed by a positive excursion which persisted also after the event. The aim of this study is to reconstruct variations in biogenic carbonate production of calcareous nannofossils through the Aptian in order to detect if and how it has been affected by high pCO2. Calcareous nannoplankton is an excellent proxy for reconstructing present and paste surface water conditions, being extremely sensitive to changes in physical and chemical conditions of the oceans (pH). Calcareous nannoplankton act both as biological and carbonate pump, thus changes in nannoplankton assemblages affect the organic and inorganic carbon cycles. This makes coccolithophores key-organisms for understanding the biological pump and adsorption of atmospheric CO2 into the oceans. Experiments on living coccolithophores indicates that coccolith type, abundance and degree of mineralization depend on chemical-physical-trophic conditions as well as on pCO2. Production of dwarf/malformed coccoliths has been documented in the geological record through OAE 1a. Here we present quantitative analyses of nannofossil micrite in thin sections, reconstructing nannofossil absolute abundances and calcite paleofluxes in three drill sites: the Cismon core (Northern Italy), Piobbico core (Central Italy) and DSDP Site 463 in the mid-Pacific Mountains. In these sites, nannofossil absolute abundances and paleofluxes show a

  20. [Self-medication, self-prescription and medicating «by proxy» in paediatrics].

    Science.gov (United States)

    Valenzuela Ortiz, María; Sánchez Ruiz-Cabello, Francisco Javier; Uberos, José; Checa Ros, Ana Fátima; Valenzuela Ortiz, Cristina; Augustín Morales, María Carmen; Muñoz Hoyos, Antonio

    2017-05-01

    Self-prescribing or medicating 'by proxy' is not an autonomous, free and voluntary decision in the case of children. On the contrary, in this case it is based on the subjective interpretation of symptoms made by the mother or by a third person who is legally responsible for the minor. In our opinion, to analyse this situation is of great importance in order to know the determining factors, perceptions, and realities related to this problem. Our proposal is to perform a prospective observational study for analysing maternal and familiar determinant factors related to self-prescribing and self-medicating 'by proxy' in paediatrics. A validated survey was developed to be applied to mothers of children aged 0 to 14 who are users of the Paediatric Emergency Department in a hospital. A total of 1,714 mothers were recruited in a random period of time. This sample included 345 mothers who exclusively self-medicated their children (case group), and 1,369 mothers (control group) who did not meet this requirement. The overall percentage of medicating 'by proxy' was 32.8%. There is a significant association between self-medicating and educational level of the mother, the number of children, and the birth order among siblings. Neither maternal age nor social-occupational level are related to this problem. Most frequently used drugs include antipyretics and 'anticatharrals', usually administered as a monotherapy. Our results seem to indicate that the educational level and the parental experience acquired with previous children could generate the required confidence in parents to choose the medication by themselves. Almost 85% of these drugs come from the 'home first-aid kit.' Copyright © 2016 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  1. Geochemical proxies of North American freshwater routing during the Younger Dryas cold event.

    Science.gov (United States)

    Carlson, Anders E; Clark, Peter U; Haley, Brian A; Klinkhammer, Gary P; Simmons, Kathleen; Brook, Edward J; Meissner, Katrin J

    2007-04-17

    The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from approximately 12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (DeltaMg/Ca, U/Ca, and (87)Sr/(86)Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic delta(18)O(seawater) and delta(13)C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 +/- 0.02 Sverdrup (1 Sverdrup = 10(6) m(3).s(-1)). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of approximately 0.06-0.12 Sverdrup, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.

  2. How do roots alter signals of molecular proxies in terrestrial archives?

    Science.gov (United States)

    Wiesenberg, G. L.; Gocke, M. I.

    2016-12-01

    Terrestrial archives such as sediment-paleosol sequences and recent soil profiles have been frequently used for environmental and paleoenvironmental studies. One prominent tool is the use of molecular proxies from the lipid fraction due to their relative persistence and their well known suitability to trace paleoenvironmental developments as well as human activities. However, excavations of sediment-paleosol sequences often reveal the presence of roots or biopores that might have been formed during any later stage of pedogenesis or sediment accumulation, potentially altering the signal of molecular proxies. In the current study, we compile recent soils and paleosols as well as several meter thick sediment-paleosol sequences in order to trace the influence by post-pedogenic/sedimentary root penetration on molecular composition. Therefore, we documented root frequencies during field sampling campaigns and collected root (remains) with their surrounding material to assess the extension of root-derived overprint. While only suberin analysis enables identification of root-derived biomass in the vicinity of living or ancient roots, other biomarkers such as alkanes and fatty acids can derive from the primary vegetation and are commonly assumed to be only aboveground litter-derived. Further, miroorganisms and root-derived biomass contribute to lipid assemblage in soils and sediments. Therefore, their source identification and attribution to root-origin is more difficult, as also promoted degradation in the vicinity of roots can alter the biomarker signal. In the surrounding of visible root remains, we could identify root-derived overprint of up to >8cm distance, whereas this is mainly attributed to finer side roots around visible root remains. Furthermore, alteration can strongly overprint the sedimentary signal due to long-lasting overprint, especially in nutrient-rich horizons, such as paleosols. To enable proper paleoenvironmental reconstructions in terrestrial

  3. Organic molecules in the polar ice: from chemical analysis to environmental proxies

    Science.gov (United States)

    Barbante, Carlo; Zennaro, Piero; Giorio, Chiara; Kehrwald, Natalie; Benton, Alisa K.; Wolff, Eric W.; Kalberer, Markus; Kirchgeorg, Torben; Zangrando, Roberta; Barbaro, Elena; Gambaro, Andrea

    2015-04-01

    The molecular and isotopic compositions of organic matter buried in ice contains information that helps reconstruct past environmental conditions, evaluate histories of climate change, and assess impacts of humans on ecosystems. In recent years novel analytical techniques were developed to quantify molecular compounds in ice cores. As an example, biomass burning markers, including monosaccharide anhydrides, lightweight carboxylic acids, lignin and resin pyrolysis products, black carbon, and charcoal records help in reconstructing past fire activity across seasonal to millennial time scales. Terrestrial biomarkers, such as plant waxes (e.g. long-chain n-alkanes) are also a promising paleo vegetation proxy in ice core studies. Polycyclic aromatic hydrocarbons are ubiquitous pollutants recently detected in ice cores. These hydrocarbons primarily originate from incomplete combustion of organic matter and fossil fuels (e.g. diesel engines, domestic heating, industrial combustion) and therefore can be tracers of past combustion activities. In order to be suitable for paloeclimate purposes, organic molecular markers detected in ice cores should include the following important features. Markers have to be stable under oxidizing atmospheric conditions, and ideally should not react with hydroxyl radicals, during their transport to polar regions. Organic markers must be released in large amounts in order to be detected at remote distances from the sources. Proxies must be specific, in order to differentiate them from other markers with multiple sources. The extraction of glaciochemical information from ice cores is challenging due to the low concentrations of some impurities, thereby demanding rigorous control of external contamination sources and sensitive analytical techniques. Here, we review the analysis and use of organic molecules in ice as proxies of important environmental and climatic processes.

  4. A New Proxy Electronic Voting Scheme Achieved by Six-Particle Entangled States

    Science.gov (United States)

    Cao, Hai-Jing; Ding, Li-Yuan; Jiang, Xiu-Li; Li, Peng-Fei

    2017-12-01

    In this paper, we use quantum proxy signature to construct a new secret electronic voting scheme. In our scheme, six particles entangled states function as quantum channels. The voter Alice, the Vote Management Center Bob, the scrutineer Charlie only perform two particles measurements on the Bell bases to realize the electronic voting process. So the scheme reduces the technical difficulty and increases operation efficiency. We use quantum key distribution and one-time pad to guarantee its unconditional security. The significant advantage of our scheme is that transmitted information capacity is twice as much as the capacity of other schemes.

  5. An Enhanced Multihoming Support Scheme with Proxy Mobile IPv6 for Convergent Networks

    Science.gov (United States)

    Li, Yang; Kum, Dong-Won; Kang, Ju-Eun; Cho, You-Ze

    This paper analyzes the limitations of the multihoming support in the Proxy Mobile IPv6 protocol, then proposes an enhanced multihoming support scheme based on a per-interface address configuration method. The proposed scheme can provide a more flexible multihoming support and also maintain application session continuity during a handoff between two interfaces by using IPv6 extension headers. Plus, flow distribution with filters is also used to realize the advantages of multihoming. Simulation results with the OPNET validate the proposed multihoming support scheme for convergent networks.

  6. Improving age-depth models using sedimentary proxies for accumulation rates in fluvio-lacustrine deposits

    Science.gov (United States)

    Minderhoud, Philip S. J.; Cohen, Kim M.; Toonen, Willem. H. J.; Erkens, Gilles; Hoek, Wim Z.

    2017-04-01

    Lacustrine fills, including those of oxbow lakes in river floodplains, often hold valuable sedimentary and biological proxy records of palaeo-environmental change. Precise dating of accumulated sediments at levels throughout these records is crucial for interpretation and correlation of (proxy) data existing within the fills. Typically, dates are gathered from multiple sampled levels and their results are combined in age-depth models to estimate the ages of events identified between the datings. In this paper, a method of age-depth modelling is presented that varies the vertical accumulation rate of the lake fill based on continuous sedimentary data. In between Bayesian calibrated radiocarbon dates, this produces a modified non-linear age-depth relation based on sedimentology rather than linear or spline interpolation. The method is showcased on a core of an infilled palaeomeander at the floodplain edge of the river Rhine near Rheinberg (Germany). The sequence spans from 4.7 to 2.9 ka cal BP and consists of 5.5 meters of laminated lacustrine, organo-clastic mud, covered by 1 meter of peaty clay. Four radiocarbon dates provide direct dating control, mapping and dating in the wider surroundings provide additional control. The laminated, organo-clastic facies of the oxbow fill contains a record of nearby fluvial-geomorphological activity, including meander reconfiguration events and passage of rare large floods, recognized as fluctuations in coarseness and amount of allochthonous clastic sediment input. Continuous along-core sampling and measurement of loss-on-ignition (LOI) provided a fast way of expressing the variation in clastic sedimentation influx from the nearby river versus autochthonous organic deposition derived from biogenic production in the lake itself. This low-cost sedimentary proxy data feeds into the age-depth modelling. The sedimentology-modelled age-depth relation (re)produces the distinct lithological boundaries in the fill as marked changes in

  7. A quantum proxy group signature scheme based on an entangled five-qubit state

    Science.gov (United States)

    Wang, Meiling; Ma, Wenping; Wang, Lili; Yin, Xunru

    2015-09-01

    A quantum proxy group signature (QPGS) scheme based on controlled teleportation is presented, by using the entangled five-qubit quantum state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. The security of the scheme is guaranteed by the entanglement correlations of the entangled five-qubit state, the secret keys based on the quantum key distribution (QKD) and the one-time pad algorithm, all of which have been proven to be unconditionally secure and the signature anonymity.

  8. Munchausen syndrome and Munchausen syndrome by proxy in a student nurse.

    Science.gov (United States)

    Yonge, Olive; Haase, Mary

    2004-01-01

    Most faculty are not prepared for the possibility of encountering Munchausen syndrome (MS) in nursing students and Munchausen syndrome by proxy (MSP) in nursing students' children. When confronted with MS or MSP, their first reaction is often hostility coupled with a sense of betrayal. Given that individuals with this condition are attracted to helping professions, the authors describe both conditions in a case in which a nursing student presented with MS and the student's daughter was a victim of MSP. The focus is on protection of any children and the public, psychiatric treatment for the offender, and assistance for faculty.

  9. A case with unexplained bleeding from multiple sites: munchausen syndrome by proxy.

    Science.gov (United States)

    Tüfekçi, Özlem; Gözmen, Salih; Yılmaz, Şebnem; Hilkay Karapınar, Tuba; Çetin, Benhur; Burak Dursun, Onur; Emiroğlu, Neslihan; Ören, Hale; Irken, Gülersu

    2011-08-01

    Munchausen syndrome by proxy (MBP) is an extreme form of child abuse where children were unnecessarily treated or investigated for medical conditions that were falsified by their caregivers. Here the authors report a 16-year-old female with the complaints of bleeding from multiple and unusual sites, including hemoptysis, hematuria, bloody tears, and bloody nipple discharge, all of which are only witnessed by her mother. Extensive investigation revealed no organic etiologies for bleeding. The diagnosis of MBP was put by a multidisciplinary team. The diagnosis of MBP must be kept in mind in conditions where there is no underlying organic pathology in a bleeding patient.

  10. The role of nonperpetrating fathers in Munchausen syndrome by proxy: a review of the literature.

    Science.gov (United States)

    Morrell, Briyana; Tilley, Donna Scott

    2012-08-01

    Munchausen syndrome by proxy (MSBP) is a psychiatric condition and form of child abuse in which a caregiver, usually a mother, induces illness in a child to gain attention for herself. Because children that are abused by a MSBP perpetrator are likely to be hospitalized multiple times, it is important for the nurse to know warning signs and symptoms of MSBP. Of particular interest is the role of the child's parent that is not involved in the abuse, usually the father. This article presents a review of literature on MSBP, focusing on the role of the nonperpetrating fathers. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. [Fortuitous discovery of intracerebral foreign body leads to the diagnosis of Munchausen syndrome by proxy].

    Science.gov (United States)

    Bouaziz Abed, A; Mustapha, R; Chiha, M

    2011-11-01

    An intracerebral foreign body is a rare situation in childhood. It often occurs accidentally with transorbital or more rarely transnasal penetration. We report the case of a child who had been followed since the age of 2.5 months for chronic vomiting without failure to thrive. The fortuitous discovery at 22 months of age of a 4.5-cm-long sewing needle in his brain probably introduced via the fontanel led us to the diagnosis of Munchausen syndrome by proxy. Copyright © 2011. Published by Elsevier SAS.

  12. Combined effect of carbonate and biotite dissolution in landslides biases silicate weathering proxies

    Science.gov (United States)

    Emberson, R.; Galy, A.; Hovius, N.

    2017-09-01

    Long-term estimates of the dissolution of silicate rock are generally derived from a range of isotopic proxies, such as the radiogenic strontium isotope ratio (87Sr/86Sr), which are preserved in sediment archives. For these systems to fairly represent silicate weathering, the changes in isotopic ratios in terrestrial surface waters should correspond to changes in the overall silicate dissolution. This assumes that the silicate mineral phases that act as sources of a given isotope dissolve at a rate that is proportional to the overall silicate weathering. Bedrock landsliding exhumes large quantities of fresh rock for weathering in transient storage, and rapid weathering in these deposits is controlled primarily by dissolution of the most reactive phases. In this study, we test the hypothesis that preferential weathering of these labile minerals can decouple the dissolution of strontium sources from the actual silicate weathering rates in the rapidly eroding Western Southern Alps (WSA) of New Zealand. We find that rapid dissolution of relatively radiogenic calcite and biotite in landslides leads to high local fluxes in strontium with isotopic ratios that offer no clear discrimination between sources. These higher fluxes of radiogenic strontium are in contrast to silicate weathering rates in landslides that are not systematically elevated. On a mountain belt scale, radiogenic strontium fluxes are not coupled to volumes of recent landslides in large (>100 km2) catchments, but silicate weathering fluxes are. Such decoupling is likely due first to the broad variability in the strontium content of carbonate minerals, and second to the combination of radiogenic strontium released from both biotite and carbonate in recent landslides. This study supports previous work suggesting the limited utility of strontium isotopes as a system to study silicate weathering in the WSA. Crucially however, in settings where bedrock landsliding is a dominant erosive process there is

  13. Barium in Twilight Zone suspended matter as a potential proxy for particulate organic carbon remineralization: Results for the North Pacific

    Energy Technology Data Exchange (ETDEWEB)

    Dehairs, F.; Jacquet, S.; Savoye, N.; Van Mooy, B.A.S.; Buesseler, K.; Bishop, J.K.B.; Lamborg, C.H.; Elskens, M.; Baeyens, W.; Boyd, P.W.; Casciotti, K.L.; Monnin, C.

    2008-04-10

    This study focuses on the fate of exported organic carbon in the twilight zone at two contrasting environments in the North Pacific: the oligotrophic ALOHA site (22 degrees 45 minutes N 158 degrees W; Hawaii; studied during June-July 2004) and the mesotrophic Subarctic Pacific K2 site (47 degrees N, 161 degrees W; studied during July-August 2005). Earlier work has shown that non-lithogenic, excess particulate Ba (Ba{sub xs}) in the mesopelagic water column is a potential proxy of organic carbon remineralization. In general Ba{sub xs} contents were significantly larger at K2 than at ALOHA. At ALOHA the Ba{sub xs} profiles from repeated sampling (5 casts) showed remarkable consistency over a period of three weeks, suggesting that the system was close to being at steady state. In contrast, more variability was observed at K2 (6 casts sampled) reflecting the more dynamic physical and biological conditions prevailing in this environment. While for both sites Ba{sub xs} concentrations increased with depth, at K2 a clear maximum was present between the base of the mixed layer at around 50m and 500m, reflecting production and release of Ba{sub xs}. Larger mesopelagic Ba{sub xs} contents and larger bacterial production in the twilight zone at the K2 site indicate that more material was exported from the upper mixed layer for bacterial degradation deeper, compared to the ALOHA site. Furthermore, application of a published transfer function (Dehairs et al., 1997) relating oxygen consumption to the observed Ba{sub xs} data indicated that the latter were in good agreement with bacterial respiration, calculated from bacterial production. These results corroborate earlier findings highlighting the potential of Ba{sub xs} as a proxy for organic carbon remineralization. The range of POC remineralization rates calculated from twilight zone excess particulate Ba contents did also compare well with the depth dependent POC flux decrease as recorded by neutrally buoyant sediment traps

  14. Alcohol and premature death in Estonian men: a study of forensic autopsies using novel biomarkers and proxy informants

    Science.gov (United States)

    2012-01-01

    Background Alcohol makes an important contribution to premature mortality in many countries in Eastern Europe, including Estonia. However, the full extent of its impact, and the mechanisms underlying it, are challenging issues to research. We describe the design and initial findings of a study aimed at investigating the association of alcohol with mortality in a large series of forensic autopsies of working-age men in Estonia. Methods 1299 male deaths aged 25-54 years were subject to forensic autopsy in 2008-2009. The routine autopsy protocol was augmented by a more systematic inspection of organs, drug testing, assay of liver enzymes and novel biomarkers of alcohol consumption (EtG, EtS and PEth), together with proxy interviews with next of kin for deaths among men who lived in or close to a major town. Results 595 augmented autopsies were performed. Of these, 66% were from external causes (26% suicide, 25% poisoning). 17% were attributed to circulatory system diseases and 7% to alcoholic liver disease. Blood alcohol concentrations (BAC) of ≥ 0.2 mg/g were found for 55% of deaths. Interviews were conducted with proxy informants for 61% of the subjects who had resided in towns. Of these, 28% were reported in the previous year to have been daily or almost daily drinkers and 10% had drunk non-beverage alcohols. Blood ethanol and the liver enzyme GGT were only associated with daily drinking. However, the novel biomarkers showed a more graded response with recent consumption. In contrast, the liver enzymes AST and ALT were largely uninformative because of post-mortem changes. The presence of extremely high PEth concentrations in some samples also suggested post-mortem formation. Conclusion We have shown the feasibility of deploying an extended research protocol within the setting of routine forensic autopsies that offer scope to deepen our understanding of the alcohol-related burden of premature mortality. The most unique feature of the study is the information on a

  15. Climate inferences between paleontological, geochemical, and geophysical proxies in Late Pleistocene lacustrine sediments from Summer Lake, Oregon, western Great Basin

    Science.gov (United States)

    Heaton, Eric; Thompson, Greg; Negrini, Rob; Wigand, Peter

    2016-04-01

    Paleontological, geochemical, and geophysical data from western Great Basin pluvial Summer Lake, Oregon have established a high resolution paleoclimate record during the late Pleistocene Mono Lake Excursion (~34.75 ka), Dansgaard-Oeschger interstadials 6-8, and the end of Heinrich Even 4 (~38 ka). Proxies of grain-size, magnetic susceptibility, carbon/nitrogen ratio, ostracode analysis and palynology from a depocenter core show new results with improved age control regarding high amplitude, high frequency changes in lake level, lake temperature, and regional precipitation and temperature which correspond directly with colder/warmer and respectively drier/wetter climates as documented with Northern Atlantic Greenland ice core data. Results from geophysical and geochemical analysis, and the presence of ostracode Cytherissa lacustris consistently demonstrate the correspondence of low lake conditions and colder water temperatures during Dansgaard-Oeschger stadials and the Mono Lake Excursion. The opposite holds true during interstadials. Smaller grain size, increases in carbon/nitrogen ratio and consistent absence of C. lacustris suggest periods of increased discharge into the lake, increased lake level, and warmer water temperatures. Warmer/wetter climate conditions are confirmed during interstadials 7 and 8 from pollen analysis. Existence of Atriplex, Rosaceae, Chrysothamnus and Ambrosia, and pollen ratios of Juniperus/Dip Pinus and (Rosaceae+Atriplex+Poaceae+Chrysothamnus+Ambrosia)/(Pinus+Picea+T. mertensiana+Sarcobatus) suggest warmer/wetter semi-arid woodland conditions during interstadials 7 and 8. This contrasts with absences in these pollens and pollen ratios indicating colder/drier continental montane woodland conditions during stadials and the Mono Lake Excursion. Increases in Juniper/Dip Pinus ratio suggest a warmer/wetter climate during interstadial 6 however additional proxies do not demonstrate comparative warmer/wetter climate, deeper lake level or

  16. Ce and Eu anomalies in zircon as proxies for the oxidation state of magmas

    Science.gov (United States)

    Trail, Dustin; Bruce Watson, E.; Tailby, Nicholas D.

    2012-11-01

    Chondrite normalized rare earth element (REE) patterns of zircons generally have enriched Ce values relative to La and Pr, and depleted Eu values relative to Sm and Gd. High Ce contents in zircon may imply oxidizing conditions (Ce4+ is more compatible than Ce3+), whereas depleted Eu contents may imply reducing conditions (Eu2+ does not substitute into the zircon lattice). We report 41 experiments in which temperature, melt composition, and oxygen fugacity (fO2) were varied in order to explore the details of Ce and Eu incorporation into zircon. Crystals were synthesized in hydrous silicate melts at 10 kbar and 800-1300 °C. Synthetic rock mixes were doped with La + Ce + Pr (±P) or Sm + Eu + Gd and buffered at oxygen fugacities ranging from ∼IW (iron-wüstite) to >MH (magnetite-hematite); the run products were analyzed by electron microprobe to obtain crystal/melt partition coefficients. Cerium anomalies increase with higher oxygen fugacities and lower crystallization temperatures. In agreement with other experimental studies, peralkaline melts yield the largest zircon grains but show only modest Ce anomalies even at fO2s > MH. The same reason that zircons grown in peralkaline melts are easy to synthesize in the laboratory (these melts are capable of dissolving wt.% levels of Zr before zircon saturation due to high alkali content) makes the melt structure/composition atypical and not representative of most natural magmas. With this in mind, we synthesized zircons in a granitic melt with more modest alkali contents that require geologically plausible Zr contents for saturation. We obtained the following empirical relationship: ln Ce/CeD=(0.1156±0.0050)×ln(fO2)+13,860±708T/(K)-6.125±0.484 where (Ce/Ce∗)D is the Ce anomaly in zircon calculated from partition coefficients, and T is the zircon crystallization temperature in K. Europium anomalies from the same melt composition are more negative at lower oxygen fugacities, but with no resolvable temperature

  17. Anomalies during the Present and Last interglacial periods - A proxy comparison

    Science.gov (United States)

    El Ouahabi, Anuar; Martrat, Belen; Lopez, Jordi F.; Grimalt, Joan O.

    2013-04-01

    The stability of the Earth's climate is strongly linked to the amount and spatial distribution of energy by atmospheric/oceanic processes from low to high latitudes. Past periods of relatively stable climate have been interrupted by sharp events, once a critical point has been passed and positive triggers and feedbacks propel change toward a contrasting mode. Additional mechanisms amplify or sustain climate changes that are already under way. High-resolution proxy archives are useful tools for characterizing these events and modes in the past, both in time and space, in order to assess the likelihood of sudden shifts, in particular within warm climate behaviour. In this respect, the PIG2LIG-4FUTURE database (Geophysical Research Abstracts Vol. 14, EGU2012-13825) contains alkenone-derived sea surface temperatures (117 marine sediment profiles) and stable oxygen isotope ratios (measured in ice cores and speleothems; 29 and 88 records respectively) with sufficient temporal resolution to understand global abrupt climate processes throughout the present interglacial (PIG) and the last interglacial (LIG), together with their deglaciations (d1 and d2). Records have been selected according to their inclusion of both the PIG and LIG intervals for the same location (no more than 45% of the sites), tight chronological control and calibration revised criteria. Data have been compiled into 200-year bins for regional stacks to help in identifying trends, transitions, boundary conditions, latitudinal temperature gradients, polar amplification and reorganisation of monsoon systems. The LIG relative to PIG anomalies are larger at mid latitudes (up to 6°C around 40N and 40S) than those for the tropics (less than 2°C from 20N to 20S). The amplitude of variation during the PIG is found to be no more than 2°C (few exceptions up to 4°C at northern sub-polar specific locations). Latitudinal distribution of anomalies appears connected to temperature seasonal contrast. The same

  18. Cost-effective handoff scheme based on mobility-aware dual pointer forwarding in proxy mobile IPv6 networks.

    Science.gov (United States)

    Son, Seungsik; Jeong, Jongpil

    2014-01-01

    In this paper, a mobility-aware Dual Pointer Forwarding scheme (mDPF) is applied in Proxy Mobile IPv6 (PMIPv6) networks. The movement of a Mobile Node (MN) is classified as intra-domain and inter-domain handoff. When the MN moves, this scheme can reduce the high signaling overhead for intra-handoff/inter-handoff, because the Local Mobility Anchor (LMA) and Mobile Access Gateway (MAG) are connected by pointer chains. In other words, a handoff is aware of low mobility between the previously attached MAG (pMAG) and newly attached MAG (nMAG), and another handoff between the previously attached LMA (pLMA) and newly attached LMA (nLMA) is aware of high mobility. Based on these mobility-aware binding updates, the overhead of the packet delivery can be reduced. Also, we analyse the binding update cost and packet delivery cost for route optimization, based on the mathematical analytic model. Analytical results show that our mDPF outperforms the PMIPv6 and the other pointer forwarding schemes, in terms of reducing the total cost of signaling.

  19. Wavelength feature mapping as a proxy to mineral chemistry for investigating geologic systems: An example from the Rodalquilar epithermal system

    Science.gov (United States)

    van der Meer, Freek; Kopačková, Veronika; Koucká, Lucie; van der Werff, Harald M. A.; van Ruitenbeek, Frank J. A.; Bakker, Wim H.

    2018-02-01

    The final product of a geologic remote sensing data analysis using multi spectral and hyperspectral images is a mineral (abundance) map. Multispectral data, such as ASTER, Landsat, SPOT, Sentinel-2, typically allow to determine qualitative estimates of what minerals are in a pixel, while hyperspectral data allow to quantify this. As input to most image classification or spectral processing approach, endmembers are required. An alternative approach to classification is to derive absorption feature characteristics such as the wavelength position of the deepest absorption, depth of the absorption and symmetry of the absorption feature from hyperspectral data. Two approaches are presented, tested and compared in this paper: the 'Wavelength Mapper' and the 'QuanTools'. Although these algorithms use a different mathematical solution to derive absorption feature wavelength and depth, and use different image post-processing, the results are consistent, comparable and reproducible. The wavelength images can be directly linked to mineral type and abundance, but more importantly also to mineral chemical composition and subtle changes thereof. This in turn allows to interpret hyperspectral data in terms of mineral chemistry changes which is a proxy to pressure-temperature of formation of minerals. We show the case of the Rodalquilar epithermal system of the southern Spanish Gabo de Gata volcanic area using HyMAP airborne hyperspectral images.

  20. Sea salt sodium record from Talos Dome (East Antarctica) as a potential proxy of the Antarctic past sea ice extent.

    Science.gov (United States)

    Severi, M; Becagli, S; Caiazzo, L; Ciardini, V; Colizza, E; Giardi, F; Mezgec, K; Scarchilli, C; Stenni, B; Thomas, E R; Traversi, R; Udisti, R

    2017-06-01

    Antarctic sea ice has shown an increasing trend in recent decades, but with strong regional differences from one sector to another of the Southern Ocean. The Ross Sea and the Indian sectors have seen an increase in sea ice during the satellite era (1979 onwards). Here we present a record of ssNa(+) flux in the Talos Dome region during a 25-year period spanning from 1979 to 2003, showing that this marker could be used as a potential proxy for reconstructing the sea ice extent in the Ross Sea and Western Pacific Ocean at least for recent decades. After finding a positive relationship between the maxima in sea ice extent for a 25-year period, we used this relationship in the TALDICE record in order to reconstruct the sea ice conditions over the 20th century. Our tentative reconstruction highlighted a decline in the sea ice extent (SIE) starting in the 1950s and pointed out a higher variability of SIE starting from the 1960s and that the largest sea ice extents of the last century occurred during the 1990s. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Frederico S. da Silva

    2010-01-01

    Full Text Available The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

  2. Automated Storm Tracking and the Lightning Jump Algorithm Using GOES-R Geostationary Lightning Mapper (GLM) Proxy Data

    Science.gov (United States)

    Schultz, Elise; Schultz, Christopher Joseph; Carey, Lawrence D.; Cecil, Daniel J.; Bateman, Monte

    2016-01-01

    This study develops a fully automated lightning jump system encompassing objective storm tracking, Geostationary Lightning Mapper proxy data, and the lightning jump algorithm (LJA), which are important elements in the transition of the LJA concept from a research to an operational based algorithm. Storm cluster tracking is based on a product created from the combination of a radar parameter (vertically integrated liquid, VIL), and lightning information (flash rate density). Evaluations showed that the spatial scale of tracked features or storm clusters had a large impact on the lightning jump system performance, where increasing spatial scale size resulted in decreased dynamic range of the system's performance. This framework will also serve as a means to refine the LJA itself to enhance its operational applicability. Parameters within the system are isolated and the system's performance is evaluated with adjustments to parameter sensitivity. The system's performance is evaluated using the probability of detection (POD) and false alarm ratio (FAR) statistics. Of the algorithm parameters tested, sigma-level (metric of lightning jump strength) and flash rate threshold influenced the system's performance the most. Finally, verification methodologies are investigated. It is discovered that minor changes in verification methodology can dramatically impact the evaluation of the lightning jump system.

  3. Alberta oil sands community exposure and health effects assessment : analysis of health records as a proxy for health outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.; Mackenzie, A.; Schopflocher, D.; Shaw, S.; Robb, J.; Gabos, S. [Alberta Health and Wellness, Edmonton, AB (Canada)

    2002-07-01

    A large scale study was conducted to assess potential links between air quality and human health outcomes. Health records were used as a proxy measure for health outcomes. Residents of Fort McMurray and Lethbridge, Alberta, Canada were used in the comparison of risks of selected morbidity and mortality measures during a 3 year period between 1995 and 1998. Data on the socio-demography, morbidity, and mortality were linked by PI and geographic area from the Health Care Insurance Plan, physical and hospital billing systems, and vital statistics death registration. Age was the most important confounder. Asthma incidence for children 3 years or less was examined along with prevalence and mortality of selected diseases for each sex and age group. Results showed that the incidence of asthma varied by age and sex but not by study area. There was no major difference in death from lung cancer, cardiovascular disease, coronary heart disease, respiratory disorders and COPD between residents of the target and control communities. 6 figs.

  4. Extreme Wave Deposits On The Pacific Coast Of Mexico: Tsunamis Or Storms? - A Multi-Proxy Approach

    Science.gov (United States)

    Ramirez Herrera, M.; Lagos, M.; Hutchinson, I.; Chague-Goff, C.; Kostoglodov, V.; Goff, J. R.; Ruiz-Fernandez, A.; Machain, M.; Caballero, M.; Goguitchaichrili, A.; Aguilar, B.; Urquijo, P.; Laboratorio Universitario de Geofísica Ambiental (Luga)

    2011-12-01

    Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa-Zihuatanejo and Michoacán coast. The purpose of our study was two-fold, a) to determine whether we could distinguish storm from tsunami deposits, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa-Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted as the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, and laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating) indicate the occurrence of two tsunamis that we link to local events: the 1985 Mexico and possibly the 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico.

  5. Extreme wave deposits on the Pacific coast of Mexico: Tsunamis or storms? — A multi-proxy approach

    Science.gov (United States)

    Ramírez-Herrera, María-Teresa; Lagos, Marcelo; Hutchinson, Ian; Kostoglodov, Vladimir; Machain, Maria Luisa; Caballero, Margarita; Goguitchaichvili, Avto; Aguilar, Bertha; Chagué-Goff, Catherine; Goff, James; Ruiz-Fernández, Ana-Carolina; Ortiz, Modesto; Nava, Hector; Bautista, Francisco; Lopez, Gloria I.; Quintana, Patricia

    2012-02-01

    Historical and instrumental data show that the Pacific coast of Mexico has been exposed to destructive tsunamis over at least the past 500 years. This coast is also affected by hurricanes generated in the eastern Pacific. The great 1985 Mexico earthquake and its aftershock generated tsunamis that affected the Ixtapa-Zihuatanejo and Michoacán coast. The purpose of our study was two-fold — a) to determine whether storm and tsunami deposits could be distinguished, and b) whether tsunami deposits from historical events are preserved in the tropical environments of the Ixtapa-Zihuatanejo coast. Two anomalous sand units in the Ixtapa estuary are interpreted to be the result of high-energy marine inundation events that occurred in the last century. Several lines of evidence using a multi-proxy approach (historical studies, interviews with local witnesses, geomorphological and geological surveys, coring and trenching, laboratory analyses including grain size, micropaleontology, geochemistry, magnetic susceptibility and radiometric dating, and numerical modeling) indicate the occurrence of two tsunamis that we link to local events: the 21st September 1985 Mexico and possibly the 14th March 1979 Petatlan earthquakes. We thereby provide the first onshore geological evidence of historical tsunamis on the Pacific coast of Mexico.

  6. Mid-late Holocene climate, demography, and cultural dynamics in Iberia: A multi-proxy approach

    Science.gov (United States)

    Lillios, Katina T.; Blanco-González, Antonio; Drake, Brandon Lee; López-Sáez, José Antonio

    2016-03-01

    Despite increasing interest in the relationship between culture transformation and abrupt climate change, their complexities are poorly understood. The local impact of global environmental fluctuations depends on multiple factors, and their effects on societal collapse are often assumed rather than demonstrated. One of the major changes in west European later prehistory was the Copper to Bronze Age transition, contemporaneous with the 4.2 ky cal. BP event. This article offers a multi-dimensional insight into this historical process in the Iberian Peninsula from a multi-proxy and comparative perspective. Three study areas, representative of diverse ecological settings and historical trajectories, are compared. Using radiocarbon dates, 13C discrimination (Δ13C) values on C3 plants, and high-resolution palynological records as palaeoclimatic and palaeodemographic proxies, this study tracks the uneven signals of Holocene climate. The wettest Northwest region features the most stable trend lines, whereas the Southwest exhibits an abrupt decrease in its demographic signals c. 4500 cal. BP, which is then followed by a subsequent rise in the neighbouring Southeast. These lines of evidence suggest the possibility, never previously noted, of demic migration from the Southwest to the Southeast in the Early Bronze Age as a contributing factor to the cultural dynamics of southern Iberia.

  7. Surrogate taxa and fossils as reliable proxies of spatial biodiversity patterns in marine benthic communities.

    Science.gov (United States)

    Tyler, Carrie L; Kowalewski, Michał

    2017-03-15

    Rigorous documentation of spatial heterogeneity (β-diversity) in present-day and preindustrial ecosystems is required to assess how marine communities respond to environmental and anthropogenic drivers. However, the overwhelming majority of contemporary and palaeontological assessments have centred on single higher taxa. To evaluate the validity of single taxa as community surrogates and palaeontological proxies, we compared macrobenthic communities and sympatric death assemblages at 52 localities in Onslow Bay (NC, USA). Compositional heterogeneity did not differ significantly across datasets based on live molluscs, live non-molluscs, and all live organisms. Death assemblages were less heterogeneous spatially, likely reflecting homogenization by time-averaging. Nevertheless, live and dead datasets were greater than 80% congruent in pairwise comparisons to the literature estimates of β-diversity in other marine ecosystems, yielded concordant bathymetric gradients, and produced nearly identical ordinations consistently delineating habitats. Congruent estimates from molluscs and non-molluscs suggest that single groups can serve as reliable community proxies. High spatial fidelity of death assemblages supports the emerging paradigm of Conservation Palaeobiology. Integrated analyses of ecological and palaeontological data based on surrogate taxa can quantify anthropogenic changes in marine ecosystems and advance our understanding of spatial and temporal aspects of biodiversity. © 2017 The Author(s).

  8. Conflicts in Africa and Major Powers: Proxy Wars, Zones of Influence or Provocative Instability

    Directory of Open Access Journals (Sweden)

    Jerry Rowlings Tafotie

    2016-12-01

    Full Text Available The article analyses the different nature of conflicts that have occurred in Africa since the end of Cold War. A special attention is given to the role of external factors in the process of conflict evolution and the escalation of violence on the African continent. In effect, this paper demonstrates through a critical examination of the meaning of proxy war as, zone of influence or provocation of instability as a strategy and an analysis of its employment by the United States and China, France etc. in Africa. The new potential confrontation between the United States and China as in Sudan, France in its former coloniesis not only based on a clash of world views about the structure and nature of international relations and security but largely over the control of strategically vital energy resources based in Africa. The authors conclude that this ultimately creates permanent tensions or bitter conflicts between the actors and African populations as a factor that have negative impact on the peace and stability of continent. According to the context of superpower conflict strategies, this paper critically examines, zone of influence, provoking of instability or proxy war as a viable national strategy of nuclear armed great powers in advancing and/or defending their global national interests in a bipolar/multipolar international system.

  9. Ethical use of covert videoing techniques in detecting Munchausen syndrome by proxy.

    Science.gov (United States)

    Foreman, D M; Farsides, C

    1993-01-01

    Munchausen syndrome by proxy is an especially malignant form of child abuse in which the carer (usually the mother) fabricates or exacerbates illness in the child to obtain medical attention. It can result in serious illness and even death of the child and it is difficult to detect. Some investigators have used video to monitor the carer's interaction with the child without obtaining consent--covert videoing. The technique presents several ethical problems, including exposure of the child to further abuse and a breach of trust between carer, child, and the professionals. Although covert videoing can be justified in restricted circumstances, new abuse procedures under the Children Act now seem to make its use unethical in most cases. Sufficient evidence should mostly be obtained from separation of the child and carer or videoing with consent to enable action to be taken to protect the child under an assessment order. If the new statutory instruments prove ineffective in Munchausen syndrome by proxy covert videoing may need to be re-evaluated. PMID:8401021

  10. 'Munchausen syndrome by proxy' presenting as battered child syndrome: a report of two cases.

    Science.gov (United States)

    Sugandhan, Selvendran; Gupta, Somesh; Khandpur, Sujay; Khanna, Neena; Mehta, Manju; Inna, Prashanth

    2010-06-01

    Child abuse is a major public health crisis and is on the rise. Dermatologists are frequently involved in its evaluation in differentiating abusive injuries from accidental injuries and in excluding pathological conditions that may mimic abuse. Battered child syndrome or physical abuse is not only a common form of child abuse but can also result from a rarer form of child abuse known as Munchausen syndrome by proxy. In this form of abuse, mother, who is the usual perpetrator, induces an illness or abuses the child for her own self-serving psychological needs. We report two cases of battered child syndrome. In both the cases, Psychiatric evaluation was performed on both parents. Observation through one-way mirror was done with the mother and the child alone. Routine hematological and biochemical investigations were done. Diagnosis of Munchausen syndrome by proxy was firmly established in one case and was considered as a possibility in the other. A multidisciplinary team effort is essential in evaluating such cases, and dermatologists should be aware and be well informed about this condition that can be potentially lethal but easily overlooked.

  11. Epidemiology of Munchausen syndrome by proxy, non-accidental poisoning, and non-accidental suffocation.

    Science.gov (United States)

    McClure, R J; Davis, P M; Meadow, S R; Sibert, J R

    1996-01-01

    A two year prospective study was performed to determine the epidemiology of Munchausen syndrome by proxy, non-accidental poisoning, and non-accidental suffocation in the UK and the Republic of Ireland. Cases were notified to the British Paediatric Association Surveillance Unit from September 1992 to August 1994 if a formal case conference had been held for the first time during that period to discuss any of the above conditions. A total of 128 cases were identified: 55 suffered Munchausen syndrome by proxy alone, 15 poisoning, and 15 suffocation; 43 suffered more than one type of abuse. The majority of children were aged under 5 years, the median age being 20 months. On 85% of occasions the perpetrator was the child's mother. In 42% of families with more than one child, a sibling had previously suffered some form of abuse. Eighty five per cent of notifying paediatricians considered the probability of their diagnosis as virtually certain before a case conference was convened. The commonest drugs used to poison were anticonvulsants; opiates were the second commonest. Sixty eight children suffered severe illness of whom eight died. The combined annual incidence of these conditions in children aged under 16 years is at least 0.5/100,000, and for children aged under 1, at least 2.8/100,000. PMID:8813872

  12. Calcium Nodules as a Proxy for Quaternary Paleoclimate Change on China’s Loess Plateau

    Science.gov (United States)

    He, Wenming; He, Hongming; Zhu, Mingyong

    2015-01-01

    Different proxies have been used to investigate Quaternary paleoclimate change. Here, we used weathering of calcium nodules in paleosols on China’s Loess Plateau as a proxy for Quaternary paleoclimate changes to provide an alternative indicator of these changes. Paleosol and carbonate nodules were collected from Luochuan and Lantian counties in Shaanxi Province, China. We found that this approach allowed quantitative reconstruction of temperature, rainfall, soil mineral composition, and the effects of weathering and leaching. The changes in carbonate content in the loess and paleosol sequences were controlled by alternating dry and wet climatic conditions. Nodule formation conditions were directly affected by the leaching and migration of elements. The loess and paleosol sequences developed calcium nodules, and their formation was closely related to the rainfall and leaching characteristics of the paleoclimate. The paleoclimate and soil minerals affected the vegetation types and directly influenced changes in the soil. During formation of the calcium nodules, the surface vegetation evolved slowly, and the number of species and quantity of vegetation both decreased. PMID:26633304

  13. Calcium Nodules as a Proxy for Quaternary Paleoclimate Change on China's Loess Plateau.

    Science.gov (United States)

    He, Wenming; He, Hongming; Zhu, Mingyong

    2015-01-01

    Different proxies have been used to investigate Quaternary paleoclimate change. Here, we used weathering of calcium nodules in paleosols on China's Loess Plateau as a proxy for Quaternary paleoclimate changes to provide an alternative indicator of these changes. Paleosol and carbonate nodules were collected from Luochuan and Lantian counties in Shaanxi Province, China. We found that this approach allowed quantitative reconstruction of temperature, rainfall, soil mineral composition, and the effects of weathering and leaching. The changes in carbonate content in the loess and paleosol sequences were controlled by alternating dry and wet climatic conditions. Nodule formation conditions were directly affected by the leaching and migration of elements. The loess and paleosol sequences developed calcium nodules, and their formation was closely related to the rainfall and leaching characteristics of the paleoclimate. The paleoclimate and soil minerals affected the vegetation types and directly influenced changes in the soil. During formation of the calcium nodules, the surface vegetation evolved slowly, and the number of species and quantity of vegetation both decreased.

  14. Trace element profiles in sediments as proxies of dead zone history; rhenium compared to molybdenum.

    Science.gov (United States)

    Helz, George R; Adelson, Jordan M

    2013-02-05

    Warm-season dead zones-volumes of coastal water containing too little O(2) to support macrofauna-are a growing global menace. Trace elements that are deposited in sediments in response to reducing or sulfidic conditions can provide proxy records for reconstructing dead zone evolution. Based on relative enrichment in reduced vs oxidized marine sediments, Re seems promising as a dead zone proxy. Here, Re is determined by isotope dilution mass spectrometry in sediments underlying the summertime dead zone in Chesapeake Bay. Contrary to expectation, Re becomes only modestly (∼2-fold) elevated during the 20th century and fails to track the historic record of summertime O(2) depletion. Rhenium enrichments are watershed-specific and apparently controlled by anthropogenic sources, not by redox-linked authigenic processes. In contrast, Mo enrichments do track historic O(2) depletion. Three factors cause redox control to override anthropogenic control in the case of Mo: relative to weathering fluxes, anthropogenic Mo fluxes are weaker than Re fluxes; during anoxic periods, Mn refluxing amplifies Mo but not Re concentrations near the sediment surface; and high pore water sulfide-polysulfide promotes Mo fixation in pyrite while promoting formation of organo-Re adducts; the latter are too mobile and reactive to preserve a reliable historic record under seasonally fluctuating redox conditions.

  15. Cost-Effective and Fast Handoff Scheme in Proxy Mobile IPv6 Networks with Multicasting Support

    Directory of Open Access Journals (Sweden)

    Illkyun Im

    2014-01-01

    Full Text Available With recent advancements in wireless communication technologies, mobile multicasting is becoming important, in an effort to use network resources more efficiently. In the past, when various mobile IP-based multicast techniques were proposed, the focus was on the costs needed for network delivery to provide multicast services, as well as on minimizing the multicast handover delay. However, it is fundamentally difficult to resolve the problems of handover delay and tunnel convergence for techniques using MIPv6 (Mobile IPv6, a host-based mobility management protocol. To resolve these problems, the network-based mobility management protocol PMIPv6 (Proxy Mobile IPv6 was standardized. Although performance is improved in PMIPv6 over MIPv6, it still suffers from problems of handover delay and tunnel convergence. To overcome these limitations, a technique called LFH (Low-cost and Fast Handoff is proposed in this paper, for fast and low-cost mobility management with multicasting support in PMIPv6 networks. To reduce the interactions between the complex multicast routing protocol and multicast messages, a simplified proxy method called MLD (Multicast Listener Discovery is implemented and modified. Furthermore, a TCR (Tunnel Combination and Reconstruction algorithm was used in the multicast handover procedure within the LMA (Local Mobility Anchor domain, as well as in the multicast handover procedure between domains, in order to overcome the problem of tunnel convergence. It was found that, compared to other types of multicast techniques, LFH reduces multicast delay, and requires lower cost.

  16. Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands

    Science.gov (United States)

    Amesbury, M. J.; Charman, D. J.; Newnham, R. M.; Loader, N. J.; Goodrich, J. P.; Royles, J.; Campbell, D. I.; Roland, T. P.; Gallego-Sala, A.

    2015-09-01

    Carbon stable isotope (δ13C) records from vascular plant dominated peatlands have been used as a palaeoclimate proxy, but a better empirical understanding of fractionation processes in these ecosystems is required. Here, we test the potential of δ13C analysis of ombrotrophic restiad peatlands in New Zealand, dominated by the wire rush (Empodisma spp.), to provide a methodology for developing palaeoclimatic records. We took surface plant samples alongside measurements of water table depth and (micro)climate over spatial (six sites spanning > 10° latitude) and temporal (monthly measurements over 1 year) gradients and analysed the relationships between cellulose δ13C values and environmental parameters. We found strong, significant negative correlations between δ13C and temperature, photosynthetically active radiation and growing degree days above 0 °C. No significant relationships were observed between δ13C and precipitation, relative humidity, soil moisture or water table depth, suggesting no growing season water limitation and a decoupling of the expected link between δ13C in vascular plants and hydrological variables. δ13C of Empodisma spp. roots may therefore provide a valuable temperature proxy in a climatically sensitive region, but further physiological and sub-fossil calibration studies are required to fully understand the observed signal.

  17. Characterization of Proxy Application Performance on Advanced Architectures. UMT2013, MCB, AMG2013

    Energy Technology Data Exchange (ETDEWEB)

    Howell, Louis H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gunney, Brian T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bhatele, Abhinav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-09

    Three codes were tested at LLNL as part of a Tri-Lab effort to make detailed assessments of several proxy applications on various advanced architectures, with the eventual goal of extending these assessments to codes of programmatic interest running more realistic simulations. Teams from Sandia and Los Alamos tested proxy apps of their own. The focus in this report is on the LLNL codes UMT2013, MCB, and AMG2013. We present weak and strong MPI scaling results and studies of OpenMP efficiency on a large BG/Q system at LLNL, with comparison against similar tests on an Intel Sandy Bridge TLCC2 system. The hardware counters on BG/Q provide detailed information on many aspects of on-node performance, while information from the mpiP tool gives insight into the reasons for the differing scaling behavior on these two different architectures. Results from three more speculative tests are also included: one that exploits NVRAM as extended memory, one that studies performance under a power bound, and one that illustrates the effects of changing the torus network mapping on BG/Q.

  18. Validation of commercial business lists as a proxy for licensed alcohol outlets.

    Science.gov (United States)

    Carlos, Heather A; Gabrielli, Joy; Sargent, James D

    2017-05-19

    Studies of retail alcohol outlets are restricted to regions due to lack of U.S. national data. Commercial business lists (BL) offer a possible solution, but no data exists to determine if BLs could serve as an adequate proxy for license data. This paper compares geospatial measures of alcohol outlets derived from a commercial BL with license data for a large US state. We validated BL data as a measure of off-premise alcohol outlet density and proximity compared to license data for 5528 randomly selected California residential addresses. We calculated three proximity measures (Euclidean distance, road network travel time and distance) and two density measures (kernel density estimation and the count within a 2-mile radius) for each dataset. The data was acquired in 2015 and processed and analyzed in 2015 and 2016. Correlations and reliabilities between density (correlation 0.98; Cronbach's α 0.97-0.99) and proximity (correlations 0.77-0.86; α 0.87-0.92) measures were high. For proximity, BL data matched license in 55-57% of addresses, overstated distance in 19%, and understated in 24-26%. BL data can serve as a reliable proxy for licensed alcohol outlets, thus extending the work that can be performed in studies on associations between retail alcohol outlets and drinking outcomes.

  19. Parents were accurate proxy reporters of urgent pediatric asthma health services: a retrospective agreement analysis.

    Science.gov (United States)

    Ungar, Wendy J; Davidson-Grimwood, Sara R; Cousins, Martha

    2007-11-01

    To assess agreement between parents' proxy reports of children's respiratory-related health service use and administrative data. A retrospective analysis of statistical agreement between clinical and claims data for reports of physician visits, emergency department (ED) visits, and hospitalizations in 545 asthmatic children recruited from sites in the greater Toronto area was conducted. Health services use data were extracted from the Ontario Health Insurance Plan and Canadian Institute for Health Information databases for each child for the interval coinciding with the proxy report for each health service type. Agreement between administrative data and respondent reports (n=545) was substantial for hospitalizations in the past year (kappa=0.80 [0.74, 0.86]), moderate for ED visits in the past year (kappa=0.60 [0.53, 0.67]), and slight for physician visits (kappa=0.13 [0.00, 0.27]) in the past 6 months. Income, parent's education, and child quality-of-life symptom scores did not affect agreement. Agreement for ED visits was significantly higher (Phealth services utilization.

  20. Phytolith indices as proxies of grass subfamilies on East African tropical mountains

    Science.gov (United States)

    Bremond, Laurent; Alexandre, Anne; Wooller, Matthew J.; Hély, Christelle; Williamson, David; Schäfer, Peter A.; Majule, Amos; Guiot, Joël

    2008-04-01

    The main objective of this paper is to provide researchers that investigate fossil phytolith assemblages and model/data comparisons a new tool for estimating C 3/C 4 grass composition over time. We tested the reliability of modern soil phytolith assemblages and phytolith indices for tracing the dominance of different grass subfamilies and tree cover density. We analyzed modern soil phytolith assemblages from sites over elevation gradients on Mount Kenya (Kenya), Mount Rungwe and around Lake Masoko (southern Tanzania). These data were compared with available botanical data. A phytolith index named Ic, proved to be an effective proxy of the proportions of Pooideae, Arundinoideae and Bambusoideae grasses (mainly C 3 grasses) versus Panicoideae grasses (mainly C 4 grasses), increasing with elevation in East-Africa. When tropical mountains are covered by open habitats (e.g . grasses and shrublands), Ic should be a reliable proxy of the C 3/C 4 grass composition. These results highlight the value of the phytolith index Ic, when interpreting paleo-environmental records from tropical mountains, to: 1) better understand past local and regional C 3/C 4 grass distributions and associated climatic changes and 2) increase the set of C 3/C 4 data available for model/data comparisons.