WorldWideScience

Sample records for multi proxy evidence

  1. Multi-proxy studies in palaeolimnology

    OpenAIRE

    Birks, Hilary H.; Birks, Harry John Betteley

    2006-01-01

    Multi-proxy studies are becoming increasingly common in palaeolimnology. Eight basic requirements and challenges for a multi-proxy study are outlined in this essay – definition of research questions, leadership, site selection and coring, data storage, chronology, presentation of results, numerical tools, and data interpretation. The nature of proxy data is discussed in terms of physical proxies and biotic proxies. Loss-on-ignition changes and the use of transfer functions are reviewed as exa...

  2. Holocene climate changes in eastern Beringia (NW North America) – A systematic review of multi-proxy evidence

    Science.gov (United States)

    Kaufman, Darrell S.; Axford, Yarrow L.; Henderson, Andrew C.G.; McKay, Nicolas P.; Oswald, W. Wyatt; Saenger, Casey; Anderson, R. Scott; Bailey, Hannah L.; Clegg, Benjamin; Gajewski, Konrad; Hu, Feng Sheng; Jones, Miriam C.; Massa, Charly; Routson, Cody C.; Werner, Al; Wooller, Matthew J.; Yu, Zicheng

    2016-01-01

    Reconstructing climates of the past relies on a variety of evidence from a large number of sites to capture the varied features of climate and the spatial heterogeneity of climate change. This review summarizes available information from diverse Holocene paleoenvironmental records across eastern Beringia (Alaska, westernmost Canada and adjacent seas), and it quantifies the primary trends of temperature- and moisture-sensitive records based in part on midges, pollen, and biogeochemical indicators (compiled in the recently published Arctic Holocene database, and updated here to v2.1). The composite time series from these proxy records are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies to clarify multi-centennial- to millennial-scale trends in Holocene climate change. To focus the synthesis, the paleo data are used to frame specific questions that can be addressed with simulations by Earth system models to investigate the causes and dynamics of past and future climate change. This systematic review shows that, during the early Holocene (11.7–8.2 ka; 1 ka = 1000 cal yr BP), rather than a prominent thermal maximum as suggested previously, temperatures were highly variable, at times both higher and lower than present (approximate mid-20th-century average), with no clear spatial pattern. Composited pollen, midge and other proxy records average out the variability and show the overall lowest summer and mean-annual temperatures across the study region during the earliest Holocene, followed by warming over the early Holocene. The sparse data available on early Holocene glaciation show that glaciers in southern Alaska were as extensive then as they were during the late Holocene. Early Holocene lake levels were low in interior Alaska, but moisture indicators show pronounced differences across the region. The highest

  3. Multi-proxy evidence of long-term changes in ecosystem structure in a Danish marine estuary, linked to increased nutrient loading

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Clarke, A.L.; Reuss, Nina Steenberg

    2006-01-01

    and prompting debate on the causes. This paper reports a multi-proxy survey of 210Pb-dated sediment cores from the anoxic basin. Analyses of diatoms, dinoflagellates, pigments and geochemical proxies were used to determine changes in ecosystem structure over the past 100 years. The aim was to establish ‘base......-line conditions', for management purposes, of the biological structure prior to 1900, and to examine possible causes of changes observed. Geochemical proxies total nitrogen (TN), total carbon (TC) and biogenic silica (BSi) were consistently high throughout the sediment record. Increased concentrations of pigments...... and natural isotopes (d13C, d15N) suggested increasing production and nutrient loading. The main changes in the biological proxies occurred between 1915 and the 1940s, and indicated that the estuary has been somewhat eutrophic since 1900, but that the eutrophication process increased over the past 100 years...

  4. Multi-proxy evidence of long-term changes in ecosystem structure in a Danish marine estuary, linked to increased nutrient loading

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Clarke, A.L.; Reuss, Nina Steenberg

    2006-01-01

    This paper presents a study of changes in eutrophication over the past 100 years in a fertile estuary. The Danish estuary Mariager Fjord is a long, narrow sill-fjord with a permanently anoxic basin. In 1997 anoxia spread from the basin to the entire inner estuary, killing almost all eukaryotes...... and prompting debate on the causes. This paper reports a multi-proxy survey of 210Pb-dated sediment cores from the anoxic basin. Analyses of diatoms, dinoflagellates, pigments and geochemical proxies were used to determine changes in ecosystem structure over the past 100 years. The aim was to establish ‘base...... and natural isotopes (d13C, d15N) suggested increasing production and nutrient loading. The main changes in the biological proxies occurred between 1915 and the 1940s, and indicated that the estuary has been somewhat eutrophic since 1900, but that the eutrophication process increased over the past 100 years...

  5. 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.)

  6. 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. PMID:24670874

  7. A multi-proxy perspective on millennium-long climate variability in the Southern Pyrenees

    NARCIS (Netherlands)

    Morellón, M.; Pérez-Sanz, A.; Corella, J.P.; Büntgen, U.; Catalán, J.; González-Samprizé, P.; González-Trueba, J.J.; López-Sáez, J.A.; Moreno, A.; Pla-Rabes, S.; Saz-Sánchez, M.Á.; Scussolini, P.; Serrano, E.; Steinhilber, F.; Stefanova, V.; Vegas-Vilarrúbia, T.; Valero-Garcés, B.

    2012-01-01

    This paper reviews multi-proxy paleoclimatic reconstructions with robust age-control derived from lacustrine, dendrochronological and geomorphological records and characterizes the main environmental changes that occurred in the Southern Pyrenees during the last millennium. Warmer and relatively

  8. A 13000-year, high-resolution multi-proxy record of climate variability with episodes of enhanced atmospheric dust in Western Asia: Evidence from Neor peat complex in NW Iran

    Science.gov (United States)

    Sharifi, O.; Pourmand, A.; Canuel, E. A.; Peterson, L. C.

    2011-12-01

    The regional climate over West Asia, extending between Iran and the Arabian Peninsula to the eastern Mediterranean Sea, is governed by interactions between three major synoptic systems; mid-latitude Westerlies, the Siberian Anticyclone and the Indian Ocean Summer Monsoon. In recent years, a number of paleoclimate studies have drawn potential links between episodes of abrupt climate change during the Holocene, and the rise and fall of human civilizations across the "Fertile Crescent" of West Asia. High-resolution archives of climate variability from this region, however, are scarce, and at times contradicting. For example, while pollen and planktonic data from lakes in Turkey and Iran suggest that dry, continental conditions prevailed during the early-middle Holocene, oxygen isotope records indicate that relatively wet conditions dominated during this interval over West Asia. We present interannual to decadal multi-proxy records of climate variability from a peat complex in NW Iran to reconstruct changes in moisture and atmospheric dust content during the last 13000 years. Radiocarbon dating on 20 samples from a 775-cm peat core show a nearly constant rate of accumulation (1.7 mm yr-1, R2=0.99) since 13356 ± 116 cal yr B.P. Down-core X-ray fluorescence measurements of conservative lithogenic elements (e.g., Al, Zr, Ti) as well as redox-sensitive elements (e.g., Fe, K, Rb, Zn, Cu, and Co) at 2 mm intervals reveal several periods of elevated dust input to this region since the early Holocene. Down-core variations of total organic carbon and total nitrogen co-vary closely and are inversely correlated with conservative lithogenic elements (Al, Si, Ti), indicating a potential link between climate change and accumulation of organic carbon in the Neor peat mire. Major episodes of enhanced dust deposition (13000-12000, 11700-11200, 9200-8800, 7000-6000, 4200-3200, 2800-2200 and 1500-600 cal yr B.P) are in good agreement with other proxy records that document more arid

  9. A Multi-Proxy Paradigm in the Pursuit of Ocean Paleoredox

    Science.gov (United States)

    Anbar, A. D.; Duan, Y.; Kendall, B.; Reinhard, C.; Severmann, S.; Lyons, T. W.

    2011-12-01

    The geologic record provides abundant evidence for variations in ocean oxygenation throughout Earth history. Expansion of ocean anoxic zones is expected in the future as a consequence of global climate change, with attendant effects on global nutrient inventories, carbon cycling and fluxes of trace greenhouse gases to the atmosphere. Therefore, studying ancient ocean redox variations not only teaches us about the history of the Earth system, but also provides insights into how the system may respond to analogous human perturbations. However, the extent, duration, causes, and consequences of most past variations are poorly understood. This problem motivates the development of paleoredox proxies, including novel stable isotope systems such as Mo, Fe, U and Tl. Experience with these emerging isotope systems demonstrates great promise but also many challenges. The Mo isotope system is illustrative. To first order, the geochemical cycling and isotope systematics of this element are straightforward, making it a useful proxy. However, critical unresolved issues include: (a) uncertainties in the ocean inputs through time; (b) ambiguities about fractionation mechanisms; (c) inadequate understanding of how modern analogs map to ancient systems. Similar challenges confront all the novel isotope systems. The way forward requires integration of multiple isotopic proxies, as well as information gleaned from careful analyses of element concentrations. For example, an episode of Mo enrichment in the 2.5 Ga Mt. McRae Shale is generally interpreted as resulting from buildup of Mo in seawater due to oxidative weathering. This enrichment is therefore thought to indicate a "whiff" of O2 in the environment prior to the Great Oxidation Event that began at 2.4 Ga. Molybdenum isotopes are consistent with this interpretation. However, Mo enrichment due to enhanced input from low-T hydrothermal sources in an anoxic regime cannot be completely excluded given the current state of knowledge of

  10. 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.

  11. Establishing a multi-proxy approach to alpine blockfield evolution in south-central Norway

    Directory of Open Access Journals (Sweden)

    Philipp Marr

    2017-11-01

    Full Text Available Blockfields in high latitude mountain areas are a wide spread proxy for glaciation history. Their origin is debated since decades, especially in south-central Norway, where glaciation had a major global climate implication. Some authors explain old blockfield features by protection of cold-based ice, others claim they persisted as nunataks during the LGM (~20 kyr, or were formed throughout the Holocene. In order to clarify the origin of alpine blockfields we established a multi-method approach to combining lichenometry, stratigraphy, granulometry, and geochemistry (XRD, XRF. Our lichenometric dating results in conjunction with our factors indicate landscape stability for at least ~12.5 kyr. Frequent climatic shifts are evident in our profiles by varying color, LOI content and grain sizes. On the basis of geochemical analyses we were able to identify a long-term (chemical weathering history and in situ blockfield formation. The field evidences and the climatic setting of the study area leave the possibility that our location was not covered by cold-based ice during the Late-Quaternary.

  12. 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.

  13. Pleistocene climate change inferred from multi-proxy analyses of a loess-paleosol sequence in China

    Science.gov (United States)

    Wu, Yi; Qiu, Shifan; Fu, Shuqing; Rao, Zhiguo; Zhu, Zhaoyu

    2018-04-01

    The aeolian loess blanketing the Chinese Loess Plateau (CLP) is sensitive to climate change in monsoonal East Asia. Here, we present a multi-proxy climatic record from a Pleistocene loess-paleosol sequence from the Lantian Basin on the southern margin of the CLP. The measurements include magnetic susceptibility and related magnetic properties, bulk median grain-size, color reflectance, and the color-inferred hematite versus goethite ratio (Hm/Gt). A long-term aridification and cooling trend during the interval from ca 2.22-0.43 Ma is indicated by two magnetic grain-size proxies, corresponding to the global climatic cooling of the late Cenozoic. In addition, at least four intervals of climatic extremes are evident in the record of Hm/Gt ratio: at 1.71-1.65 Ma, 1.26-1.24 Ma, 0.94-0.86 Ma, and 0.62-0.48 Ma. These intervals are characterized by distinct regional climates, which contrast with the global climatic conditions represented in marine sediments. For example, a relatively arid climate is documented from 1.71 to 1.65 Ma, which was rapidly succeeded by a relatively humid climate which is associated with the earliest hominin (with an age of ca 1.63 Ma) in the Lantian Basin.

  14. Multi Service Proxy: Mobile Web Traffic Entitlement Point in 4G Core Network

    Directory of Open Access Journals (Sweden)

    Dalibor Uhlir

    2015-05-01

    Full Text Available Core part of state-of-the-art mobile networks is composed of several standard elements like GGSN (Gateway General Packet Radio Service Support Node, SGSN (Serving GPRS Support Node, F5 or MSP (Multi Service Proxy. Each node handles network traffic from a slightly different perspective, and with various goals. In this article we will focus only on the MSP, its key features and especially on related security issues. MSP handles all HTTP traffic in the mobile network and therefore it is a suitable point for the implementation of different optimization functions, e.g. to reduce the volume of data generated by YouTube or similar HTTP-based service. This article will introduce basic features and functions of MSP as well as ways of remote access and security mechanisms of this key element in state-of-the-art mobile networks.

  15. Climatic and anthropogenic controls on Mississippi River floods: a multi-proxy palaeoflood approach

    Science.gov (United States)

    Munoz, S. E.; Therrell, M. D.; Remo, J. W.; Giosan, L.; Donnelly, J. P.

    2017-12-01

    Over the last century, many of the world's major rivers have been modified for the purposes of flood mitigation, power generation, and commercial navigation. Engineering modifications to the Mississippi River system have altered the river's sediment budget and channel morphology, but the influence of these modifications on flood risk is debated. Detecting and attributing changes in river discharge is challenging because instrumental streamflow records are often too short to evaluate the range of natural hydrological variability prior to the establishment of flood mitigation infrastructure. Here we show that multi-decadal trends of flood risk on the lower Mississippi River are strongly modulated by dynamical modes of climate variability, particularly the El Niño-Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO), but that artificial channelization has greatly amplified flood magnitudes over the last century. Our results, based on a multi-proxy reconstruction of flood frequency and magnitude spanning the last five hundred years that combines sedimentary, tree-ring, and instrumental records, reveal that the magnitude of the 100-year flood has increased by 20% over the period of record, with 75% of this increase attributed to river engineering. We conclude that the interaction of human alterations to the Mississippi River system with dynamical modes of climate variability has elevated the current flood risk to levels that are unprecedented within the last five centuries.

  16. Cretaceous honeycomb oysters (Pycnodonte vesicularis) as palaeoseasonality records: A multi-proxy study

    Science.gov (United States)

    de Winter, Niels J.; Vellekoop, Johan; Vorsselmans, Robin; Golreihan, Asefeh; Petersen, Sierra V.; Meyer, Kyle W.; Speijer, Robert P.; Claeys, Philippe

    2017-04-01

    trace element and stable isotope records allow discussion of the degree to which Pycnodonte shells record their palaeoenvironment and can be used to reconstruct past sea water conditions. Preliminary results indicate that stable isotope and trace element ratios in Pynodonte shells record different seasonally changing sea water conditions in the Maastrichtian and reconstructed temperatures are consistent with results from clumped isotope analysis on the same shells and TEX86 analysis on the surrounding rocks. This multi-proxy study sheds light on the shell structure of Pycnodonte oysters, their chemical signature and growth pattern and investigates the expression of palaeoenvironmental proxies in the pristine shell calcite of these bivalves. This investigation shows the potential of using fossil Pycnodonte bivalves as a new archive for palaeoclimate reconstruction on a seasonal scale over a wide range of palaeolatitudes from the Cretaceous until the Pleistocene. References Huyghe et al. (2015) J. Geol Soc 172.5: 576-587. Videt (2003) Diss. Université Rennes 1. Wisshak, et al. (2009) Deep-Sea Res Pt I 56.3: 374-407.

  17. Correspondence of Mesozoic Eustatic Sea-Level Change with Palaeoclimate Proxies: Evidence for Glacio-Eustasy?

    Science.gov (United States)

    Simmons, M.; Davies, A.; Gréselle, B.

    2011-12-01

    Large-scale changes in stratigraphic architecture and facies that are brought about by changes in relative sea-level have been the focus of much academic and industry study over the last few decades. The authors, plus numerous colleagues, have studied over 11,000 stratigraphic sections worldwide. By applying biostratigraphic and chemostratigraphic calibration in suitable locations from this dataset it is possible to demonstrate over 250 synchronous global sequence stratigraphic events in the Phanerozoic including over 100 in the Mesozoic. This then raises the question - what causes globally synchronous eustatic sea-level change? To answer this question requires an understanding of both the pace and amplitude of the observed eustatic sea-level change. In successions where duration can be deduced from orbital forcing cycles, our observed sea-level changes appear to be relatively rapid - less than 500,000 years, for example, for sea-level rises in the Late Jurassic. The amplitude of such rises is in the order of tens of metres. Such rates and amplitudes as inferred from our global model preclude tectonism as a primary driver and implicate glacio-eustacy as a key driving mechanism, even in supposed "greenhouse times". Given the clear economic importance of understanding the underlying mechanisms driving this eustatic change we have compiled records of key isotopic proxies through the entire Mesozoic in an effort to explore the relationship between global sea-level and palaeoclimate. Our research reveals a clear link between many large-scale maximum flooding events with known episodes of palaeoclimatic warming and between climatic cooling events and lowstand intervals, further implicating glacio-eustacy. In addition to the isotopic proxy evidence we have also compiled direct indicators for the occurrence of cold polar conditions, including the presence of ice sheets, in the Mesozoic (e.g. tillites, glendonites). This has been incorporated into plate tectonic

  18. A nonlinear multi-proxy model based on manifold learning to reconstruct water temperature from high resolution trace element profiles in biogenic carbonates

    Directory of Open Access Journals (Sweden)

    M. Bauwens

    2010-11-01

    Full Text Available A long standing problem in paleoceanography concerns the reconstruction of water temperature from δ18O carbonate. It is problematic in the case of freshwater influenced environments because the δ18O isotopic composition of the ambient water (related to salinity needs to be known. In this paper we argue for the use of a nonlinear multi-proxy method called Weight Determination by Manifold Regularization (WDMR to develop a temperature reconstruction model that is less sensitive to salinity variations. The motivation for using this type of model is twofold: firstly, observed nonlinear relations between specific proxies and water temperature motivate the use of nonlinear models. Secondly, the use of multi-proxy models enables salinity related variations of a given temperature proxy to be explained by salinity-related information carried by a separate proxy. Our findings confirm that Mg/Ca is a powerful paleothermometer and highlight that reconstruction performance based on this proxy is improved significantly by combining its information with the information for other trace elements in multi-proxy models. Although the models presented here are black-box models that do not use any prior knowledge about the proxies, the comparison of model reconstruction performances based on different proxy combinations do yield useful information about proxy characteristics. Using Mg/Ca, Sr/Ca, Ba/Ca and Pb/Ca the WDMR model enables a temperature reconstruction with a root mean squared error of ± 2.19 °C for a salinity range between 15 and 32.

  19. The Use of Proxy Caches for File Access in a Multi-Tier Grid Environment

    International Nuclear Information System (INIS)

    Brun, R; Duellmann, D; Ganis, G; Janyst, L; Peters, A J; Rademakers, F; Sindrilaru, E; Hanushevsky, A

    2011-01-01

    The use of proxy caches has been extensively studied in the HEP environment for efficient access of database data and showed significant performance with only very moderate operational effort at higher grid tiers (T2, T3). In this contribution we propose to apply the same concept to the area of file access and analyse the possible performance gains, operational impact on site services and applicability to different HEP use cases. Base on a proof-of-concept studies with a modified XROOT proxy server we review the cache efficiency and overheads for access patterns of typical ROOT based analysis programs. We conclude with a discussion of the potential role of this new component at the different tiers of a distributed computing grid.

  20. Multi-proxy reconstructions of precipitation field in China over the past 500 years.

    OpenAIRE

    Shi, Feng; Zhao, sen; Guo, Zhengtang; Goosse, Hugues; Yin, Qiuzhen

    2017-01-01

    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. Ba...

  1. Multi-proxy reconstructions of hydrologic change during the Eocene-Oligocene transition in the North American Interior

    Science.gov (United States)

    Eley, Y.; Hren, M. T.

    2016-12-01

    The dramatic shift from a 'greenhouse' to an 'icehouse' world that occurred during the Eocene-Oligocene transition (EOT, 34-33.5 Ma) is associated with changes in atmospheric and oceanic circulation patterns, extinction events in both marine and terrestrial ecosystems, and the establishment of a continental-scale ice sheet on Antarctica. Terrestrial records of the EOT, however, show limited consensus regarding the intensity and impact of this transition, complicating our understanding of how terrestrial hydrology responds to climatic change of this magnitude. Stable isotopes of fossil bones and teeth from the White River Group (WRG) in Nebraska have been interpreted to show an 8 °C decrease in mean annual temperatures across the EOT, with an increase in seasonality, however these studies find no evidence for accompanying changes in aridity. Conversely, other studies have inferred increased aridity in the early Oligocene based on changes in the δ18O and δ13C values of mammalian tooth enamel sampled from the same location. Some of this ambiguity is likely to stem from the difficulty in separating the influence of factors such as temperature, water availability and atmospheric circulation patterns on the δ18O composition of ungulate tooth enamel. We present paired leaf wax biomarker and clay hydrogen isotope data from the WRG to produce a new multi-proxy record of hydrological change and accompanying ecosystem shifts through the EOT in the North American interior. Hydrogen isotopes of clay minerals show a negative shift of record a negative shift in excess of 50‰, in tandem with a positive change in average chain length. We infer an increase in aridity from these data, with an associated potential shift in vegetation cover towards more savannah-style plant species as the climate became drier during the transition into the Oligocene. These data provide new constraints on the impact of the EOT in North America, and highlight the potential role of increasing

  2. A multi-proxy analysis of Late Quaternary ocean and climate variability for the Maldives, Inner Sea

    Science.gov (United States)

    Bunzel, Dorothea; Schmiedl, Gerhard; Lindhorst, Sebastian; Mackensen, Andreas; Reolid, Jesús; Romahn, Sarah; Betzler, Christian

    2017-12-01

    As a natural sediment trap, the marine sediments of the sheltered central part of the Maldives Inner Sea represent an exceptional archive for paleoenvironmental and climate changes in the equatorial Indian Ocean. To evaluate the complex interplay between high-latitude and monsoonal climate variability, related dust fluxes, and regional oceanographic responses, we focused on Fe / Al, Ti / Al and Si / Ca ratios as proxies for terrigenous sediment delivery and total organic carbon (TOC) and Br XRF counts as proxies for marine productivity. Benthic foraminiferal fauna distributions, grain size and stable δ18O and δ13C data were used for evaluating changes in the benthic ecosystem and changes in the intermediate water circulation, bottom water current velocity and oxygenation. Our multi-proxy data record reveals an enhanced dust supply during the glacial intervals, causing elevated Fe / Al and Si / Ca ratios, an overall coarsening of the sediment and an increasing amount of agglutinated benthic foraminifera. The enhanced dust fluxes can be attributed to higher dust availability in the Asian desert and loess areas and its transport by intensified winter monsoon winds during glacial conditions. These combined effects of wind-induced mixing of surface waters and dust fertilization during the cold phases resulted in an increased surface water productivity and related organic carbon fluxes. Thus, the development of highly diverse benthic foraminiferal faunas with certain detritus and suspension feeders was fostered. The difference in the δ13C signal between epifaunal and deep infaunal benthic foraminifera reveals intermediate water oxygen concentrations between approximately 40 and 100 µmol kg-1 during this time. The precessional fluctuation pattern of oxygen changes resembles that from the deep Arabian Sea, suggesting an expansion of the oxygen minimum zone (OMZ) from the Arabian Sea into the tropical Indian Ocean with a probable regional signal of strengthened winter

  3. A multi-proxy geochemical investigation of late-Quaternary paleoenvironmental change from Burial Lake, Noatak National Preserve, Alaska

    Science.gov (United States)

    Finkenbinder, M. S.; Abbott, M.; Stoner, J. S.; Dorfman, J. M.

    2012-12-01

    Here we present a new multi-proxy geochemical analysis of paleoenvironmental change inferred from sediment cores recovered from Burial Lake (68.434° N, 159.174° W; 430 m ASL) in northwest Alaska. Previous work on cores from 7.9 m water depth sampled at comparatively low resolution revealed basal sediments date to ~ 40,000 cal yr BP and an unconformity during a period of aridity around the Last Glacial Maximum (LGM). We therefore collected multiple overlapping Livingston cores from the lake depocenter (21.5 m water depth) in the summer of 2010 in an effort to develop a temporally continuous, high resolution record spanning prior to the LGM to the present. We focus our interpretations on a 6.51 m core developed through wiggle matching proxy data from core sites A10 and C10. We use traditional laboratory methods and investigate new approaches to assess changes in sedimentation and productivity. We are measuring dry bulk density, organic matter via Loss-on-ignition at 550° C, biogenic silica, magnetic susceptibility, grain size via laser diffractometry, and elemental abundances via scanning x-ray fluorescence (XRF). Future research seeks to test the reliability of two commonly used XRF proxies, for organic matter (incoherence/coherence ratios) and aquatic productivity (Si/Ti ratios). Age control is provided by 12 Accelerator Mass Spectrometry radiocarbon dates of discrete terrestrial macrofossils. Results from these analyses indicate that the depocenter core is continuous and the sediment record spans the last ~ 38,000 cal yr BP and most importantly contains sediments spanning the LGM. Preliminary geochemical results demonstrate substantial cyclicity in organic matter and aquatic productivity beginning in the late-glacial. We seek to analyze the periodicity of these proxies through spectral analysis, although initial observations suggest multi-century to millennial scale variability. In addition, we note the presence of two abrupt, non-linear transitions in organic

  4. Multi-proxy reconstructions and the power of integration across marine, terrestrial, and freshwater ecosystems. (Invited)

    Science.gov (United States)

    Black, B.

    2013-12-01

    Over the past decade, dendrochronology (tree-ring analysis) techniques have been increasingly applied to growth increments of various bivalve, fish, and coral species. In particular, the use of crossdating ensures that all increments in a dataset have assigned the correct calendar year of formation and that the resulting chronology is exactly placed in time. Such temporal alignment facilitates direct comparisons among chronologies that span diverse taxa and ecosystems, illustrating the pervasive, synchronizing influence of climate from alpine forests to the continental slope. Such an approach can be particularly beneficial to reconstructions in that each species captures climate signals from its unique 'perspective' of life history and habitat. For example, combinations of tree-ring data and chronologies for the long-lived bivalve Pacific geoduck (Panopea generosa) capture substantially more variance in regional sea surface temperatures than either proxy could explain alone. Just as importantly, networks of chronologies spanning multiple trophic levels can help identify climate variables critical to ecosystem functioning, which can then be targeted to generate most biologically relevant reconstructions possible. Along the west coast of North America, fish and bivalve chronologies in combination with records of seabird reproductive success indicate that winter sea-level pressure is closely associated with California Current productivity, which can be hind-cast over the past six centuries using coastal tree-ring chronologies. Thus, multiple proxies not only increase reconstruction skill, but also help isolate climate variables most closely linked to ecosystem structure and functioning.

  5. 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

  6. Multi-proxy experimental calibration in cold water corals for high resolution paleoreconstructions

    Science.gov (United States)

    Pelejero, C.; Martínez-Dios, A.; Ko, S.; Sherrell, R. M.; Kozdon, R.; López-Sanz, À.; Calvo, E.

    2017-12-01

    Cold-water corals (CWCs) display an almost cosmopolitan distribution over a wide range of depths. Similar to their tropical counterparts, they can provide continuous, high-resolution records of up to a century or more. Several CWC elemental and isotopic ratios have been suggested as useful proxies, but robust calibrations under controlled conditions in aquaria are needed. Whereas a few such calibrations have been performed for tropical corals, they are still pending for CWCs. This reflects the technical challenges involved in maintaining these slow-growing animals alive during the long-term experiments required to achieve sufficient skeletal growth for geochemical analyses. We will show details of the set up and initial stages of a long-term experiment being run at the ICM (Barcelona), where live specimens (>150) of Desmophyllum dianthus sampled in Comau Fjord (Chile) are kept under controlled and manipulated physical chemistry (temperature, pH, phosphate, barium, cadmium) and feeding conditions. With this set up, we aim to calibrate experimentally several specific elemental ratios including P/Ca, Ba/Ca, Cd/Ca, B/Ca, U/Ca and Mg/Li as proxies of nutrients dynamics, pH, carbonate ion concentration and temperature. For the trace element analysis, we are analyzing coral skeletons using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), running quantitative analyses on spot sizes of tens of microns, and comparing to micromilling and solution ICP-MS. Preliminary data obtained using these techniques will be presented, as well as measurements of calcification rate. Since coral-water corals are potentially vulnerable to ocean acidification, the same experiment is being exploited to assess potential effects of the pH stressor in D. dianthus; main findings to date will be summarized.

  7. Past climate variability between 97 and 7 ka reconstructed from a multi proxy speleothem record from Western Cuba

    Science.gov (United States)

    Winterhalder, Sophie; Scholz, Denis; Mangini, Augusto; Spötl, Christoph; Jochum, Klaus Peter; Pajón, Jesús M.

    2016-04-01

    The tropical hydrological cycle plays a key role in regulating global climate, mainly through the export of heat and moisture to higher latitudes, and is highly sensitive to climate change, for instance due to changes in the position of the Intertropical Convergence Zone (ITCZ). Previous work on Caribbean stalagmites suggests a strong connection of precipitation variability to North Atlantic (NA) sea surface temperatures on multidecadal to millenial timescales (Fensterer et al., 2012; Fensterer et al., 2013; Winter et al., 2011). Cold phases in the NA potentially lead to a southward shift of the ITCZ and thus drier conditions in Cuba. On orbital timescales, Cuban stalagmites suggest a relation of speleothem δ18O values with the δ18O value of Caribbean surface waters (Fensterer et al., 2013). Here we present an expansion of the Cuban speleothem record covering the whole last glacial period from the end of MIS5c (97 ka BP) until 7 ka with hiatuses between 93-80 ka, 37-35 ka and 13-10 ka. Stalagmite Cuba medio (CM) has been precisely dated with 60 230Th/U-ages, mainly performed by the MC-ICPMS technique. The δ18O and δ13C records are completed by a continuous, high resolution LA-ICPMS trace element profile. These data allow for the first time to establish a multi-proxy climate reconstruction for the North Western Caribbean at decadal to centennial resolution for this period. The long-term variability of the δ18O values probably reflects rainfall amount in Cuba. The response to some Dansgaard/Oeschger and Heinrich stadials confirms the previously observed correlation between Caribbean and NA climate variability. However, this connection is not clearly imprinted throughout the record. Furthermore, trace elements, such as Mg, do not proof without ambiguity drier conditions in Cuba during NA cold events, such as the Heinrich stadials. This suggests that climate variability in Cuba was more complex during the last 100ka, and that the NA was not the only driving factor

  8. 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.

  9. 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

  10. 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.

  11. Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: a multi-proxy perspective

    Science.gov (United States)

    Dowsett, Harry J.; Robinson, Marci M.

    2009-01-01

    The Mid-Pliocene is the most recent interval of sustained global warmth, which can be used to examine conditions predicted for the near future. An accurate spatial representation of the low-latitude Mid-Pliocene Pacific surface ocean is necessary to understand past climate change in the light of forecasts of future change. Mid-Pliocene sea surface temperature (SST) anomalies show a strong contrast between the western equatorial Pacific (WEP) and eastern equatorial Pacific (EEP) regardless of proxy (faunal, alkenone and Mg/Ca). All WEP sites show small differences from modern mean annual temperature, but all EEP sites show significant positive deviation from present-day temperatures by as much as 4.4°C. Our reconstruction reflects SSTs similar to modern in the WEP, warmer than modern in the EEP and eastward extension of the WEP warm pool. The east-west equatorial Pacific SST gradient is decreased, but the pole to equator gradient does not change appreciably. We find it improbable that increased greenhouse gases (GHG) alone would cause such a heterogeneous warming and more likely that the cause of Mid-Pliocene warmth is a combination of several forcings including both increased meridional heat transport and increased GHG.

  12. Multi-proxy Organic Geochemical Reconstruction of Holocene Hydroclimate Near the Western Greenland Ice Sheet Margin

    Science.gov (United States)

    Cluett, A.; Thomas, E. K.

    2017-12-01

    Anthropogenic warming is projected to drive profound change to the Arctic hydrological cycle within the century, most notably in the intensification of rainfall, with potential feedbacks to the climate system and cryosphere. However, the relationship between hydroclimate and cryosphere variability is poorly constrained in the long-term due to a scarcity of high-resolution hydroclimate records from the Arctic. We analyze the stable hydrogen isotopes (dD) of leaf wax biomarkers from lacustrine sediments spanning the Holocene to 9000 cal. year B.P. from Lake Gus (67.032ºN, 52.427ºW, 300 m a.s.l.; informal name), a small lake approximately 90 km from the modern western margin of the Greenland Ice Sheet. We interpret the signal of aquatic leaf wax isotopes in the context of a survey of 100 modern lake water samples from western Greenland across an aridity gradient to better understand the combined climatological and hydrological controls on lake water dD in the study area. We compare variability of aquatic and terrestrial leaf wax isotopes to infer changes in relative moisture throughout the Holocene, and complement our leaf wax record with analysis of glycerol dialkyl glycerol tetraethers (GDGTs) and alkenones, to produce records of summer temperature. Pairing temperature and leaf wax isotope records provides a means to constrain the changing dD-temperature relationship throughout the Holocene and infer moisture source variability. In combination, these proxies produce a comprehensive hydroclimate record at approximately centennial scale to evaluate shifts in relative moisture, temperature, and moisture source, and to investigate the interaction between hydroclimate and Greenland Ice Sheet margin fluctuations through the Holocene.

  13. Climate in Sweden during the past millennium - Evidence from proxy data, instrumental data and model simulations

    Energy Technology Data Exchange (ETDEWEB)

    Moberg, Anders; Gouirand, Isabelle; Schoning, Kristian; Wohlfarth, Barbara [Stockholm Univ. (Sweden). Dept. of Physical Geography and Quaternary Geology; Kjellstroem, Erik; Rummukainen, Markku [Swedish Meteorological and Hydrological Inst., Norrkoeping (Sweden). Rossby Centre; Jong, Rixt de [Lund Univ. (Sweden). Dept. of Quaternary Geology; Linderholm, Hans [Goeteborg Univ. (Sweden). Dept. of Earth Sciences; Zorita, Eduardo [GKSS Research Centre, Geesthacht (Germany)

    2006-12-15

    Knowledge about climatic variations is essential for SKB in its safety assessments of a geological repository for spent nuclear waste. There is therefore a need for information about possible future climatic variations under a range of possible climatic states. However, predictions of future climate in any deterministic sense are still beyond our reach. We can, nevertheless, try to estimate the magnitude of future climate variability and change due to natural forcing factors, by means of inferences drawn from natural climate variability in the past. Indeed, the climate of the future will be shaped by the sum of natural and anthropogenic climate forcing, as well as the internal climate variability. The aim here is to review and analyse the knowledge about Swedish climate variability, essentially during the past millennium. Available climate proxy data and long instrumental records provide empirical information on past climatic changes. We also demonstrate how climate modelling can be used to extend such knowledge. We use output from a global climate model driven with reconstructed radiative forcings (solar, volcanic and greenhouse gas forcing), to provide boundary conditions for a regional climate model. The regional model provides more details of the climate than the global model, and we develop a simulated climate history for Sweden that is complete in time and space and physically consistent. We use output from a regional model simulation for long periods in the last millennium, to study annual mean temperature, precipitation and runoff for the northern and southern parts of Sweden. The simulated data are used to place corresponding instrumental records for the 20th century into a plausible historical perspective. We also use output from the regional model to study how the frequency distribution of the daily temperature, precipitation, runoff and evaporation at Forsmark and Oskarshamn could have varied between unusually warm and cold 30-year periods during the

  14. Climate in Sweden during the past millennium - Evidence from proxy data, instrumental data and model simulations

    International Nuclear Information System (INIS)

    Moberg, Anders; Gouirand, Isabelle; Schoning, Kristian; Wohlfarth, Barbara

    2006-12-01

    Knowledge about climatic variations is essential for SKB in its safety assessments of a geological repository for spent nuclear waste. There is therefore a need for information about possible future climatic variations under a range of possible climatic states. However, predictions of future climate in any deterministic sense are still beyond our reach. We can, nevertheless, try to estimate the magnitude of future climate variability and change due to natural forcing factors, by means of inferences drawn from natural climate variability in the past. Indeed, the climate of the future will be shaped by the sum of natural and anthropogenic climate forcing, as well as the internal climate variability. The aim here is to review and analyse the knowledge about Swedish climate variability, essentially during the past millennium. Available climate proxy data and long instrumental records provide empirical information on past climatic changes. We also demonstrate how climate modelling can be used to extend such knowledge. We use output from a global climate model driven with reconstructed radiative forcings (solar, volcanic and greenhouse gas forcing), to provide boundary conditions for a regional climate model. The regional model provides more details of the climate than the global model, and we develop a simulated climate history for Sweden that is complete in time and space and physically consistent. We use output from a regional model simulation for long periods in the last millennium, to study annual mean temperature, precipitation and runoff for the northern and southern parts of Sweden. The simulated data are used to place corresponding instrumental records for the 20th century into a plausible historical perspective. We also use output from the regional model to study how the frequency distribution of the daily temperature, precipitation, runoff and evaporation at Forsmark and Oskarshamn could have varied between unusually warm and cold 30-year periods during the

  15. A multi-proxy reconstruction of Holocene climate change from Blessberg Cave, Germany

    Science.gov (United States)

    Breitenbach, Sebastian F. M.; Plessen, Birgit; Wenz, Sarah; Leonhardt, Jens; Tjallingii, Rik; Scholz, Denis; Jochum, Klaus Peter; Marwan, Norbert

    2016-04-01

    Although Holocene climate dynamics were relatively stable compared to glacial conditions, climatic changes had significant impact on ecosystems and human society on various timescales (Mayewski et al. 2004, Donges et al. 2015, Tan et al. 2015). Precious few high-resolution records on Holocene temperature and precipitation conditions in Central Europe are available (e.g., von Grafenstein et al. 1999, Fohlmeister et al. 2012). Here we present a speleothem-based reconstruction of past climate dynamics from Blessberg Cave, Thuringia, central Germany. Three calcitic stalagmites were recovered when the cave was discovered during tunneling operations in 2008. Samples BB-1, -2 and -3 were precisely dated by the 230Th/U-method, with errors between 10 and 160 years (2σ). The combined record covers large parts of the Holocene (10 - 0.4 ka BP). δ13C and δ18O were analysed at 100 μm resolution. To gain additional insights in infiltration conditions, Sr/Ca and S/Ca were measured on BB-1 and BB-3 using an Röntgenanalytik Eagle XXL μXRF scanner. Differences to other central European records (e.g., von Grafenstein et al. 1999, Fohlmeister et al. 2012) suggest complex interaction between multiple factors influencing speleothem δ18O in Blessberg Cave. Furthermore, no clear influence of the North Atlantic Oscillation on our proxies is found. However, a link across the N Atlantic realm is indicated by a centennial-scale correlation between Blessberg δ18O values and minerogenic input into lake SS1220 in Greenland over the last 5 ka (Olsen et al. 2012). In addition, recurrence analysis indicates an imprint of Atlantic Bond events on Blessberg δ18O values (Marwan et al. 2014), corroborating the suggested link with high northern latitudes. Larger runoff into the Greenland lake seems to be associated with lower δ18O, higher δ13C and S/Ca ratios, as well as lower Sr/Ca ratios in Blessberg Cave speleothems. This might be linked to lower local temperature and/or changes in

  16. Sediment Characteristics of Mergui Basin, Andaman Sea based on Multi-proxy Analyses

    Directory of Open Access Journals (Sweden)

    Rina Zuraida

    2018-02-01

    Full Text Available This paper presents the characteristics of sediment from core BS-36 (6°55.85’ S and 96°7.48’ E, 1147.1 m water depth that was acquired in the Mergui Basin, Andaman Sea. The analyses involved megascopic description, core scanning by multi-sensor core logger, and carbonate content measurement. The purpose of this study is to determine the physical and chemical characteristics of sediment to infer the depositional environment. The results show that this core can be divided into 5 lithologic units that represent various environmental conditions. The sedimentation of the bottom part, Units V and IV were inferred to be deposited in suboxic to anoxic bottom condition combined with high productivity and low precipitation. Unit III was deposited during high precipitation and oxic condition due to ocean ventilation. In the upper part, Units II and I occurred during higher precipitation, higher carbonate production and suboxic to anoxic condition. Keywords: sediment characteristics, Mergui Basin, Andaman Sea, suboxic, anoxic, oxic, carbonate content

  17. Multi-proxy paleoenvironmental reconstruction of saline lake carbonates: Paleoclimatic and paleogeographic implications (Priabonian-Rupelian, Issirac Basin, SE France)

    Science.gov (United States)

    Lettéron, Alexandre; Fournier, François; Hamon, Youri; Villier, Loïc; Margerel, Jean-Pierre; Bouche, Alexandre; Feist, Monique; Joseph, Philippe

    2017-08-01

    A 200-m thick carbonate succession has been deposited in shallow-water, saline lake environments during the Priabonian-Rupelian in the Issirac Basin (South-East France). The palaeoenvironmental and palaeogeographic significance of such saline lake carbonates has been characterized on the basis of a multi-proxy analysis including 1) depositional and diagenetic features, 2) biological components (molluscs, ostracods, benthic foraminifers, characean) and 3) carbon, oxygen and strontium stable isotopes. Biological associations are indicative of dominantly shallow (climate (dry versus humid) are the three key factors controlling the water composition, carbonate production and depositional environments in the Issirac lake. Although the ASCI (Alès-Issirac-Saint-Chaptes) lacustrine system likely represents an athalassic (inland) lake system evolving through times, the stable isotope composition (C, O and Sr) of carbonates strongly suggests the occurrence of transient connections of the ASCI lake water with water bodies influenced by seawater and/or fed with sulfates deriving from Triassic evaporites. The Issirac Basin may be therefore interpreted as a sill area connecting the ASCI lacustrine system with the Rhône valley (Mormoiron and Valence) saline lake systems during maximum flooding periods. Finally, changes in depositional features, biota and stable isotope composition of carbonates in unit U3 suggest a transition from relatively dry to more humid climate during the uppermost Priabonian or earliest Rupelian.

  18. Rayleigh-based, multi-element coral thermometry: A biomineralization approach to developing climate proxies

    Science.gov (United States)

    Gaetani, G.A.; Cohen, A.L.; Wang, Z.; Crusius, John

    2011-01-01

    This study presents a new approach to coral thermometry that deconvolves the influence of water temperature on skeleton composition from that of “vital effects”, and has the potential to provide estimates of growth temperatures that are accurate to within a few tenths of a degree Celsius from both tropical and cold-water corals. Our results provide support for a physico-chemical model of coral biomineralization, and imply that Mg2+ substitutes directly for Ca2+ in biogenic aragonite. Recent studies have identified Rayleigh fractionation as an important influence on the elemental composition of coral skeletons. Daily, seasonal and interannual variations in the amount of aragonite precipitated by corals from each “batch” of calcifying fluid can explain why the temperature dependencies of elemental ratios in coral skeleton differ from those of abiogenic aragonites, and are highly variable among individual corals. On the basis of this new insight into the origin of “vital effects” in coral skeleton, we developed a Rayleigh-based, multi-element approach to coral thermometry. Temperature is resolved from the Rayleigh fractionation signal by combining information from multiple element ratios (e.g., Mg/Ca, Sr/Ca, Ba/Ca) to produce a mathematically over-constrained system of Rayleigh equations. Unlike conventional coral thermometers, this approach does not rely on an initial calibration of coral skeletal composition to an instrumental temperature record. Rather, considering coral skeletogenesis as a biologically mediated, physico-chemical process provides a means to extract temperature information from the skeleton composition using the Rayleigh equation and a set of experimentally determined partition coefficients. Because this approach is based on a quantitative understanding of the mechanism that produces the “vital effect” it should be possible to apply it both across scleractinian species and to corals growing in vastly different environments. Where

  19. Decade to centennial resolution hydrogen isotopic record of climate change from southern New England for the past 16 kyr: proxy validation and multi-proxy comparisons

    Science.gov (United States)

    Huang, Y.; Gao, L.; Hou, J.; Shuman, B. N.; Oswald, W.; Foster, D.

    2009-12-01

    Open system lakes in New England offer excellent archives of precipitation isotopic ratios that yield quantitative paleoclimate information. We have demonstrated previously from a lake sediment transect that hydrogen isotopic ratios of a middle-chain length fatty acid, behenic acid (BA), faithfully record precipitation isotopic ratios. We hypothesized that mid-chain n-alkyl lipids in these small lakes were primarily derived from aquatic plants that record lake water isotopic ratios. To test this hypothesis, we conducted systematic and extensive sampling of both terrestrial and aquatic plants over the past two years at two typical kettle hole lakes, Blood Pond and Rocky Pond, MA, and used a linear algebra approach to delineate percentage inputs of aquatic and terrestrial plant contributions to mid-chain n-alkyl lipids. Our results demonstrate that >92 % of the mid-chain n-alkyl lipids is derived from submerged and floating aquatic macrophytes. Our new data provide a solid basis for the application of behenic hydrogen isotopic ratios as a paleoclimate proxy from small lakes. We will present a decadal to centennial scale 16 kyr record of BA hydrogen isotopic ratios from Blood Pond, and will discuss the results in light of published pollen and lake level data. Overall, our hydrogen isotopic record is fully consistent with regional climate scenarios, including the distinctive warming at B-A events, abrupt cooling at YD event, and transition from glacial to Holcoene climate conditions. However, our high-solution isotopic data provides important new insights concerning abrupt regional climate variability. We demonstrate that the New England climate is exceptionally senstive to AMOC changes and solar forcing and that many of the abrupt climate fluctuations exert major impacts on terrestrial ecosystems, hydrology and lake levels.

  20. Nutrient regime and upwelling in the northern Benguela since the middle Holocene in a global context – a multi-proxy approach

    Directory of Open Access Journals (Sweden)

    S. Meisel

    2011-08-01

    Full Text Available The last 5500 years of climate change and environmental response in the northern Benguela Coastal Upwelling are reconstructed by means of three sediment cores from the inner shelf off central Namibia. The study is based on nutrient (δ15N, δ13C and productivity proxies (accumulation rates of total organic carbon; ARTOC. Reconstructed sea surface temperatures (alkenone-derived SST and temperatures at subsurface depths (Tδ18O; based on tests of planktonic foraminifers reflect the physical boundary conditions. The selection of proxy indicators proved a valuable basis for robust palaeo-climatic reconstructions, with the resolution ranging from multi-decadal (NAM1 over centennial (core 178 to millennial scale (core 226620. The northern Benguela experienced pronounced and rapid perturbation during the middle and late Holocene, and apparently, not all are purely local in character. In fact, numerous correlations with records from the adjacent South African subcontinent and the northern hemisphere testify to global climatic teleconnections. The Holocene Hypsithermal, for instance, is just as evident as the Little Ice Age (LIA and the Roman Warm Period. The marked SST-rise associated with the latter is substantiated by other marine and terrestrial data from the South African realm. The LIA (at least its early stages manifests itself in intensified winds and upwelling, which accords with increased rainfall receipts above the continental interior. It appears that climate signals are transferred both via the atmosphere and ocean. The combined analysis of SST and Tδ18O proved a useful tool in order to differentiate between both pathways. SSTs are primarily controlled by the intensity of atmospheric circulation features, reflecting changes of upwelling-favourable winds. Tδ18O records the temperature of the source water and often correlates with global ocean conveyor speed due to varying inputs of warm Agulhas Water. It seems as though conveyor slowdown or

  1. Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)

    Science.gov (United States)

    Kotthoff, Ulrich; Groeneveld, Jeroen; Ash, Jeanine L.; Fanget, Anne-Sophie; Quintana Krupinski, Nadine; Peyron, Odile; Stepanova, Anna; Warnock, Jonathan; Van Helmond, Niels A. G. M.; Passey, Benjamin H.; Rønø Clausen, Ole; Bennike, Ole; Andrén, Elinor; Granoszewski, Wojciech; Andrén, Thomas; Filipsson, Helena L.; Seidenkrantz, Marit-Solveig; Slomp, Caroline P.; Bauersachs, Thorsten

    2017-12-01

    Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past ˜ 8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until ˜ 7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish-marine conditions of the Littorina Sea stage (more saline and warmer) occurred within ˜ 200 years when the connection to the Kattegat became established after ˜ 7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from

  2. Multi-proxy evidence of millennial climate variability from multiple Bahamian speleothems

    Science.gov (United States)

    Arienzo, Monica M.; Swart, Peter K.; Broad, Kenneth; Clement, Amy C.; Pourmand, Ali; Kakuk, Brian

    2017-04-01

    Northern Hemisphere tropical paleoclimate records support significant changes associated with Dansgaard Oeschger (D/O) events and Heinrich stadials 1 to 6 during the last 64,000 years. However, few absolutely dated terrestrial records from the western Atlantic span the last six Heinrich stadials. Here we present geochemical results from three new stalagmites collected from a cave in the Bahamas which encompass Heinrich stadials 1 to 6. We build on a previous study of the δ13C and δ18O values of the calcite and δ18O value of fluid inclusions from a single stalagmite from the same cave spanning the last three Heinrich stadials. Absolute geochronometry using U-Th equilibrium series demonstrates that the stalagmites formed between 63.8 and 13.8 kyr BP. The δ13C and δ18O values of the calcite show higher values associated with Heinrich stadials 1-6, and lower values during the D/O interstadial events. The Sr/Ca ratios of the calcite are shown to be relatively invariant, while in two of the samples the Mg/Ca ratios track the δ13C values. Increases in the δ18O values across Heinrich stadials 1-6 are interpreted as being driven by lower temperatures. The two deeper occurring stalagmites demonstrate increased Mg/Ca ratios and δ13C values during Heinrich stadials 1 and 2 which are interpreted as a signal of reduced flow rates in the epikarst and increased water/rock interactions as a result of increased aridity which potentially occurred across all six Heinrich stadials. The observed reductions in mean annual temperature and amount of precipitation across Heinrich stadials are proposed to be driven by a reduction in sea surface temperatures in the North Atlantic and an expanded Bermuda High. During D/O interstadials, the Bahamas cave records likely indicate warmer and/or wetter climate; however the isotopic shifts are not as significant as the isotopic excursions associated with Heinrich stadials.

  3. Reconstructing palaeo-environmental conditions in the Baltic: A multi-proxy comparison from IODP Site M0059 (Little Belt)

    Science.gov (United States)

    Kotthoff, Ulrich; Andrén, Thomas; Bauersachs, Thorsten; Fanget, Anne-Sophie; Granoszewski, Wojciech; Groeneveld, Jeroen; Krupinski, Nadine; Peyron, Odile; Stepanova, Anna; Cotterill, Carol

    2015-04-01

    Some of the largest marine environmental impacts from ongoing global climate change are occurring in continental shelf seas and enclosed basins, including severe oxygen depletion, intensifying stratification, and increasing temperatures. In order to predict future changes in water mass conditions, it is essential to reconstruct how these conditions have changed in the past. The brackish Baltic Sea is one of the largest semi-enclosed basins worldwide, and hence provides a unique opportunity to analyse past changes. IODP Expedition 347 recovered a unique set of long sediment cores from the Baltic Sea Basin which allow new high-resolution reconstructions. The application of existing and development of new proxies in such a setting is complicated, as environmental changes often occur on much faster time scales with much larger variations. Therefore, we present a comparison of commonly used proxies to reconstruct palaeoecosystems, -temperatures, and -salinity from IODP Site M0059 in the Little Belt. The age model for Site M0059 is based on 14C dating and biostratigraphic correlation with neighbouring terrestrial pollen records. The aim of our study is to reconstruct the development of the terrestrial and marine ecosystems in the research area and the related environmental conditions, and to identify potential limitations for specific proxies. Pollen is used as proxy for vegetation development in the hinterland of the southern Baltic Sea and as land/air-temperature proxies. By comparison with dinoflagellate cysts and green algae remains from the same samples, a direct land-sea comparison is provided. The application of the modern analogues technique to pollen assemblages has previously yielded precise results for late Pleistocene and Holocene datasets including specific information on seasonality, but pollen-based reconstructions for Northern Europe may be hampered by plant migration effects. Chironomid remains are used where possible as indicators for surface water

  4. Middle to Late Pleistocene multi-proxy record of environmental response to climate change from the Vienna Basin, Central Europe (Austria)

    Science.gov (United States)

    Salcher, Bernhard C.; Frank-Fellner, Christa; Lomax, Johanna; Preusser, Frank; Ottner, Franz; Scholger, Robert; Wagreich, Michael

    2017-10-01

    Tectonic basins can represent valuable archives of the environmental history. Presented here are the stratigraphy and multi-proxy analyses of two adjacent alluvial fans in the Quaternary active parts of the Vienna Basin, situated at the interface of the Atlantic, European continental and Mediterranean climate. Deposits comprise a sequence of coarse-grained fluvial deposits intercalated by laterally extensive horizons of pedogenically altered fine sediments. To establish palaeoenvironmental reconstructions, fine-grained sequences from a drill core and outcrop data were analysed according to its malacofauna, palaeopedology, susceptibility and sedimentology. The chronological framework is provided by 38 luminescence ages and supported by geomagnetic polarity investigations. Distinct warm periods each associated with a geomagnetic excursion, are recorded in three pedocomplexes formed during the Last Interglacial and two earlier interglacial periods, indicted to correlate with Marine Isotope Stage (MIS) 9 and MIS 11, respectively. Environmental conditions during the early last glacial period (MIS 5, c. 100-70 ka) are reconstructed from mollusc-shell rich overbank fines deposited along a former channel belt, covered by massive sheetflood deposits during MIS 2. Analysed warm phases suggest strong variations in humidity, ranging from steppe to forest dominated environments. The study presents one of the few numerically dated Middle Pleistocene multi-proxy records and one of the most comprehensive malacological datasets covering the early phases of last glacial period of continental Europe.

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

    Directory of Open Access Journals (Sweden)

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

    Science.gov (United States)

    Shi, Feng; Zhao, Sen; Guo, Zhengtang; Goosse, Hugues; Yin, Qiuzhen

    2017-12-01

    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.

  7. Holocene multi-proxy environmental reconstruction from lake Hakluytvatnet, Amsterdamøya Island, Svalbard (79.5°N)

    Science.gov (United States)

    Gjerde, Marthe; Bakke, Jostein; D'Andrea, William J.; Balascio, Nicholas L.; Bradley, Raymond S.; Vasskog, Kristian; Ólafsdóttir, Sædis; Røthe, Torgeir O.; Perren, Bianca B.; Hormes, Anne

    2018-03-01

    High resolution proxy records of past climate are sparse in the Arctic due to low organic production that restricts the use of radiocarbon dating and challenging logistics that make data collection difficult. Here, we present a new lake record from lake Hakluytvatnet at Amsterdamøya island (79.5°N), the northwesternmost island on Svalbard. Multi-proxy analyses of lake sediments in combination with geomorphological mapping reveal large environmental shifts that have taken place at Amsterdamøya during the Holocene. A robust chronology has been established for the lake sediment core through 28 AMS radiocarbon ages, and this gives an exceptionally well-constrained age control for a lake at this latitude. The Holocene was a period with large changes in the Hakluytvatnet catchment, and the onset of the Neoglacial (ca. 5 ka) marks the start of modern-day conditions in the catchment. The Neoglacial is characterized by fluctuations in the minerogenic input to the lake as well as internal productivity, and we suggest that these fluctuations are driven by atmospherically forced precipitation changes as well as sea ice extent modulating the amount of moisture that can reach Hakluytvatnet.

  8. 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

  9. 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

  10. The Holocene warm-humid phases in the North China Plain as recorded by multi-proxy records

    Science.gov (United States)

    Cui, Jianxin; Zhou, Shangzhe; Chang, Hong

    2009-02-01

    The grain size and palinology of sediment and the frequency of 14C dada provide an integrated reconstruction of the Holocene warm-humid phases of the North China Plain. Two clear intense and long-lasting warm-humid phases were identified by comprehensive research in this region. The first phase was dated back to the early Holocene (9 000-7 000 a BP), and the second was centered at 5 000-3 000 a BP. The warm-humid episode between 9 000 and 7 000 a BP was also recognized at other sites showing global climatic trends rather than local events. Compared with the concern to the warm-humid phase of the early Holocene, the second one was not paid enough attention in the last few decades. The compilation of the Holocene paleoclimate data suggests that perhaps the second warm-humid phase was pervasive in monsoon region of China. In perspective of environmental archaeology, much attention should be devoted to it, because the flourish and adaptation of the Neolithic cultures and the building up of the first state seem to corresponding to the general warm-humid climatic conditions of this period. In addition, a warm-humid interval at 7 200-6 500 a BP was recognized by the grain size data from three sites. However, this warm-humid event was not shown in pollen assemblage and temporal distribution of 14C data. Perhaps, the resolution for climatic reconstruction from pollen and temporal distribution of 14C data cited here is relatively low and small-amplitude and short-period climatic events cannot be well reflected by the data. Due to the difference in locality and elevation of sampling site, as well as in resolution of proxy records, it is difficult to make precise correlation. Further work is needed in the future.

  11. Erosion rates across space and timescales from a multi-proxy study of rivers of eastern Taiwan

    Science.gov (United States)

    Fellin, Maria Giuditta; Chen, Chia-Yu; Willett, Sean D.; Christl, Marcus; Chen, Yue-Gau

    2017-10-01

    We derive erosion rates from detrital zircon fission-track ages and cosmogenic nuclide concentrations from sediments from the modern rivers of eastern Taiwan in order to investigate how surface erosional processes vary in space and time across the young arc-continent collisional orogen of Taiwan. Taiwan is characterized by rapid rates of exhumation, a fluvial and landslide-dominated landscape, high seismicity, high relief and frequent typhoons. The obliquity between the convergence direction and the trend of the plate boundary provides a gradient in uplift and variations in longevity of orogenic activity with a young, immature orogen in the south, a mature orogen in central and northern Taiwan, and perhaps even the cessation of orogeny in the far north. The modern zircon fission-track detrital record is consistent with basement ages that show that much of the orogen is eroding at high rates with basin-wide mean zircon fission-track cooling ages as young as 0.9 Ma. The erosion rates derived from concentrations of cosmogenic nuclides (10Be) provide erosion rates averaged over much shorter timescales, but these two proxies provide estimates of erosion rates that are within error of each other across most of the collisional belt. Erosion rates are lowest in the immature zone of the orogen (Taiwan, and increase to values ≥ 4 km/Ma in central Taiwan. Geomorphic indices, in particular channel steepness, are also correlated with erosion rates, suggesting that fluvial erosion is the dominant exhumation process and that landscape evolution is reacting primarily to tectonic forcing, fast enough to keep the landscape in a state of quasi-equilibrium where erosion rates and rock uplift rates are nearly equal. We find no measurable effects due to rock erodibility or precipitation rate, but if these parameters co-vary with tectonic uplift rate, our data could not resolve the influence of each.

  12. 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, E.J.; Tjallingii, R.; Vélez, M.I.; Rijsdijk, K.F.; Vlug, A.; Reichart, G.J.; Prendergast, A.L.; de Louw, P.G.B.; Vincent Florens, F.B.; Baider, C.; Hooghiemstra, H.

    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 2500 cal yr BP and it slowly

  13. 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

  14. Unravelling source regions of ice rafted debris within three NE Atlantic marine sediment cores during the deglacial interval: a multi-proxy approach

    Science.gov (United States)

    Small, David; Hibbert, Fiona; Austin, Bill

    2010-05-01

    Ice-rafted debris (IRD) within marine sediments of the North Atlantic provide an important archive of glacial activity on adjacent landmasses and attest to the activity of multiple calving ice margins during the last glacial cycle. IRD records therefore provide a means to reconstruct ice sheet dynamics and their interaction with the climate system, providing evidence of both the source of the ice and the location of melting (e.g. Ruddiman, 1977; Bond and Lotti, 1995). The complex interaction of the circum-Atlantic ice sheets and limitations of individual techniques often hinders firm source designations (i.e. IRD may be derived from multiple sources which cannot be differentiated by, for example, visual characterisation). Initial work identified diagnostic grain types that could be attributed to source areas of palaeo ice-sheets (eg: Bond & Lotti 1995) however, for the BIS, "diagnostic" basalt may be derived from sources to the east and west of the cores (Hibbert et al 2009, Scourse et al 2009). We therefore, utilise a multi-proxy approach to investigate the deglacial dynamics of the last British Ice Sheet (BIS) using inter alia lithic characterisation, fluxes of IRD to the core sites, magnetic susceptibility and a magnetic un-mixing model. A novel application of major element geochemistry of garnets contained within ice-rafted debris of the three high resolution marine sediment cores is presented. Garnets can be used to infer provenance (e.g. Oliver 2001) as major element composition may be assigned to specific metamorphic terranes. The IRD present within these cores is believed to be predominantly sourced from the BIS (cf: Knutz et al 2001, Hibbert et al 2009). This assertion is tested through multiple analytical techniques used and replication of records across the Hebridean shelf into the deep ocean. References • Bond, G.C. & Lotti, R., 1995. Iceberg discharges into the North Atlantic on millennial timescales during the last glaciation. Science 267. pp. 1005

  15. Multiple oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)

    Science.gov (United States)

    Bos, Johanna A. A.; De Smedt, Philippe; Demiddele, Hendrik; Hoek, Wim Z.; Langohr, Roger; Marcelino, Vera; Van Asch, Nelleke; Van Damme, Dirk; Van der Meeren, Thijs; Verniers, Jacques; Boeckx, Pascal; Boudin, Mathieu; Court-Picon, Mona; Finke, Peter; Gelorini, Vanessa; Gobert, Stefan; Heiri, Oliver; Martens, Koen; Mostaert, Frank; Serbruyns, Lynn; Van Strydonck, Mark; Crombé, Philippe

    2017-04-01

    This paper presents the results of multi-disciplinary research carried out on the deposits of Moervaart depression, NW Belgium, one of the largest palaeolakes (∼25 km2) that existed during the Lateglacial interstadial in NW Europe. The multi-proxy study, including physical (organic matter and calcium carbonate, magnetic susceptibility, micromorphological), botanical (pollen, macrofossils, diatoms), zoological (ostracods, molluscs, chironomids) and chemical analyses (stable carbon and oxygen isotopes) has resulted in a detailed reconstruction of the Lateglacial landscape as well of the local conditions that prevailed in the lake itself. A chronology of the record was provided by radiocarbon dating and comparison with radiocarbon dates of the nearby Rieme site. These yielded a good match with the regional biostratigraphy. During the Lateglacial, vegetation and geomorphology of the landscape in general changed from a tundra landscape to a boreal forest. The vegetation development, however, was interrupted by a number of cold reversals. Three centennial-scale cold oscillations are present in the record: 1) the so-called Older Dryas corresponding to GI-1d in the Greenland ice-cores, 2) a short and pronounced cold event during the early Allerød, which could be correlated to GI-1c2 and 3) a cooling event during the late Allerød probably corresponding to the Intra Allerød Cold Period (IACP) or GI-1b. The latter most likely was responsible for the disappearance of the Moervaart palaeolake.

  16. High-Arctic climate conditions for the last 7000 years inferred from multi-proxy analysis of the Bliss Lake record, North Greenland

    DEFF Research Database (Denmark)

    Olsen, Jesper; Kjær, Kurt H.; Funder, Svend Visby

    2012-01-01

    , Peary Land, Greenland. The early Holocene (10 850–10 480 cal. a BP) is characterized by increased erosion and gradually more marine conditions. Full marine conditions developed from 10 480 cal. a BP until the lake was isolated at 7220 cal. a BP. From its marine isolation at 7220 cal. a BP Bliss Lake...... becomes a lacustrine environment. Evidence from geochemical proxies (δ13C and total organic carbon) suggests that warmer conditions prevailed between 7220 and 6500 cal. a BP, corresponding to the Holocene thermal maximum, and from 3300 until 910 cal. a BP. From 850 to 500 cal. a BP colder climate...

  17. A multi-proxy record of MIS 11-12 deglaciation and glacial MIS 12 instability from the Sulmona basin (central Italy)

    Science.gov (United States)

    Regattieri, Eleonora; Giaccio, Biagio; Galli, Paolo; Nomade, Sebastien; Peronace, Edoardo; Messina, Paolo; Sposato, Andrea; Boschi, Chiara; Gemelli, Maurizio

    2016-01-01

    A multi-proxy record (lithology, XRF, CaCO3 content, carbonate δ18O and δ13C) was acquired from a sediment core drilled in the intermountain Sulmona basin (central Italy). Tephrostratigraphic analyses of three volcanic ash layers ascribe the investigated succession to the MIS 12-MIS 11 period, spanning the interval ca. 500-410 ka. Litho-pedo facies assemblage indicates predominant lacustrine deposition, interrupted by a minor sub-aerial and lake low stand episode. Variations in major and minor elements concentrations are related to changes in the clastic input to the lake. The oxygen isotopic composition of carbonate (δ18Oc) intervals is interpreted mainly as a proxy for the amount of precipitation in the high-altitude catchment of the karst recharge system. The record shows pronounced hydrological variability at orbital and millennial time-scales, which appears closely related to the Northern Hemisphere summer insolation pattern and replicates North Atlantic and west Mediterranean Sea Surface Temperature (SST) fluctuations. The MIS 12 glacial inception is marked by an abrupt reduction of precipitation, lowering of the lake level and enhanced catchment erosion. A well-defined and isotopically prominent interstadial with increased precipitation maybe related to insolation maxima-precession minima at ca. 465 ka. This interstadial ends abruptly at ca. 457 ka and it is followed by a phase of strong short-term instability. Drastic lake-level lowering and enhanced clastic flux characterized the MIS 12 glacial maximum. Lacustrine deposition restarted about 440 ka ago. The MIS 12-MIS 11 transition is characterized by a rapid increase in the precipitation, lake-level rise and reduction in the clastic input, interrupted by a short and abrupt return to drier conditions. Comparison with marine records from the Iberian margin and western Mediterranean suggests that major events of ice rafted debris deposition, related to southward migrations of the polar front, match the

  18. The Climate and Human Impacts of Major Explosive Volcanism AD670-730, A Multi-proxy Assessment

    Science.gov (United States)

    Gao, C.; Ludlow, F.

    2013-12-01

    Chronologically secure volcanic events can provide an important tool to improve ice core dating as well as our understanding of volcano-climate responses. However, there is a substantial lack of reference horizons for ice-core dating during the first millennium, excepting the Taupo (New Zealand, AD186×10) and Vesuvius (Italy, AD 79) eruptions. In this exploratory case-study, we use a total of 20 ice core records, 9 from the Arctic and 11 from the Antarctic, together with historical records to examine the occurrence and climatic impact of explosive volcanism, AD 670-730. Sulfate signals comparable in magnitude to the sizeable 1815 Tambora eruption are detected in all of the ice-core time series, with different cores attributing the timing of eruptions to AD 676×2, 688×2, or 700×2, respectively. Historical records of widespread frost damage, anomalously warm winters, drought, famine and mortality from Chinese, European and Middle Eastern chronicles suggest substantial climate and social perturbations during AD 677-685 and AD 699-709. The distinctive double-peak feature seen in the majority of the volcanic signals from both poles at AD 676×2 and AD 688×2 suggests that these signals may belong to the same eruption, with those cores dating the signals to c.AD 676 generally considered to have a more precise chronology. Combining the evidence from natural and historical anthropogenic records and taking into account uncertainties (e.g. resolution, dating accuracy) associated with individual ice cores, we propose that a (most-likely) low-latitude eruption took place around AD676, followed by another possible eruption around AD700, identifiable by the significant acidity in polar ice-caps and historical documents. Unique historical observations of 'blood rain' in Ireland (often associated with Saharan sand deposition, but also plausibly with iron and manganese-rich tephra falls) also suggest a high-latitude eruption (possibly Icelandic) at AD693, corresponding to a

  19. Evidence of active management of private voluntary pension funds in Colombia: a performance analysis using proxy ETFs

    Directory of Open Access Journals (Sweden)

    Edgardo Cayón Fallón

    2010-04-01

    Full Text Available The purpose of this study is to find evidence that shows that either active management of private pension funds in Colombia actually adds value to the investors or, on the contrary, investors would achieve better results if they invested in passively managed products such as, for example, an ETF (Exchange Trade Fund. After conducting a review of data available from 30 different private pension funds in Colombia and 30 ETFs that had similar investment goals to these portfolios, our findings reveal that, using common performance indicators, a Colombian investor would have a better ROI by investing in passively managed products (ETFs than in portfolios currently offered by voluntary pension funds in Colombia

  20. A multi-proxy record of hydroclimate, vegetation, fire, and post-settlement impacts for a subalpine plateau, Central Rocky Mountains U.S.A

    Science.gov (United States)

    Anderson, Lesleigh; Brunelle, Andrea; Thompson, Robert S.

    2015-01-01

    Apparent changes in vegetation distribution, fire, and other disturbance regimes throughout western North America have prompted investigations of the relative importance of human activities and climate change as potential causal mechanisms. Assessing the effects of Euro-American settlement is difficult because climate changes occur on multi-decadal to centennial time scales and require longer time perspectives than historic observations can provide. Here, we report vegetation and environmental changes over the past ~13,000 years as recorded in a sediment record from Bison Lake, a subalpine lake on a high plateau in northwestern Colorado. Results are based on multiple independent proxies, which include pollen, charcoal, and elemental geochemistry, and are compared with previously reported interpretations of hydroclimatic changes from oxygen isotope ratios. The pollen data indicate a slowly changing vegetation sequence from sagebrush steppe during the late glacial to coniferous forest through the late Holocene. The most dramatic vegetation changes of the Holocene occurred during the ‘Medieval Climate Anomaly’ (MCA) and ‘Little Ice Age’ (LIA) with rapid replacement of conifer forest by grassland followed by an equally rapid return to conifer forest. Late Holocene vegetation responses are mirrored by changes in fire, lake biological productivity, and watershed erosion. These combined records indicate that subsequent disturbance related to Euro-American settlement, although perhaps significant, had acted upon a landscape that was already responding to MCA-LIA hydroclimatic change. Results document both rapid and long-term subalpine grassland ecosystem dynamics driven by agents of change that can be anticipated in the future and simulated by ecosystem models.

  1. First High-Resolution Record of Late Quaternary Environmental Changes in the Amundsen Sea, West Antarctica, Revealed by Multi-proxy Analysis of Drift Sediments

    Science.gov (United States)

    Horrocks, J.; Ó Cofaigh, C.; Lloyd, J. M.; Hillenbrand, C. D.; Kuhn, G.; Smith, J.; Ehrmann, W. U.; Esper, O.

    2015-12-01

    The Amundsen Sea sector of the West Antarctic Ice Sheet (WAIS) is experiencing rapid mass loss and there is a pressing need to place the contemporary ice-sheet changes into a longer term context. The continental rise in this region is characterised by large sediment mounds that are shaped by westward flowing bottom currents and that resemble contouritic drifts existing offshore from the Antarctic Peninsula. Similar to the Antarctic Peninsula drifts, marine sediment cores from the poorly studied sediment mounds in the Amundsen Sea have the potential to provide reliable records of dynamical ice-sheet behaviour in West Antarctica and palaeoceanographic changes in the Southern Ocean during the Late Quaternary that can be reconstructed from their terrestrial, biogenic and authigenic components. Here we use multi-proxy data from three sediment cores recovered from two of the Amundsen Sea mounds to present the first high-resolution study of environmental changes on this part of the West Antarctic continental margin over the glacial-interglacial cycles of the Late Quaternary. Age constraints for the records are derived from biostratigraphy, AMS 14C dates and lithostratigraphy. We focus on the investigation of processes for drift formation, thereby using grain size and sortable silt data to reconstruct changes in bottom current speed and to identify episodes of current winnowing. Data on geochemical and mineralogical sediment composition and physical properties are used to infer both changes in terrigenous sediment supply in response to the advance and retreat of the WAIS across the Amundsen Sea shelf and changes in biological productivity that are mainly controlled by the duration of annual sea-ice coverage. We compare our data sets from the Amundsen Sea mounds to those from the well-studied Antarctic Peninsula drifts, thereby highlighting similarities and discrepancies in depositional processes and climatically-driven environmental changes.

  2. Continental Influence versus marine transition in Rio de la Plata zone - internal continental shelf of the South Atlantic - a multi proxy study

    International Nuclear Information System (INIS)

    Burone, L.; Franco-Fraguas, P.; Garcia-Rodriguez, F.; Venturini, N.; Brugnoli, E.; Muniz, P.; Ortega, L.; Marin, Y.; Mahiques, M.; Nagaic, R.; Bicegoc, M.; Figueiras, R.; Salaroli, A.

    2012-01-01

    The terrigenous proxies contribution, the organic matter origin, the productivity, the hydrodynamic and the biological records were used to determine the imrprint of the continental influence along the Rio de la Plata and the Continental Atlantic

  3. Mid- to Late Holocene climate development in Central Asia as revealed from multi-proxy analyses of sediments from Lake Son Kol (Kyrgyzstan)

    Science.gov (United States)

    Lauterbach, Stefan; Dulski, Peter; Gleixner, Gerd; Hettler-Riedel, Sabine; Mingram, Jens; Plessen, Birgit; Prasad, Sushma; Schwalb, Antje; Schwarz, Anja; Stebich, Martina; Witt, Roman

    2013-04-01

    A mid-Holocene shift from predominantly wet to significantly drier climate conditions, attributed to the weakening of the Asian summer monsoon (ASM), is documented in numerous palaeoclimate records from the monsoon-influenced parts of Asia, e.g. the Tibetan Plateau and north- and southeastern China. In contrast, Holocene climate development in the arid regions of mid-latitude Central Asia, located north and northwest of the Tibetan Plateau, is less well-constrained but supposed to have been influenced by a complex interaction between the mid-latitude Westerlies and the ASM. Hence, well-dated and highly resolved palaeoclimate records from Central Asia might provide important information about spatio-temporal changes in the regional interplay between Westerlies and ASM and thus aid the understanding of global climate teleconnections. As a part of the project CADY (Central Asian Climate Dynamics), aiming at reconstructing past climatic and hydrological variability in Central Asia, several sediment cores were recovered from alpine Lake Son Kol (41° 48'N, 75° 12'E, 3016 m a. s. l.) in the Central Tian Shan of Kyrgyzstan. A radiocarbon-dated sediment sequence of 154.5 cm length, covering approximately the last 6000 years, was investigated by using a multi-proxy approach, including sedimentological, (bio)geochemical, isotopic and micropalaeontological analyses. Preliminary proxy data indicate hydrologically variable but predominantly wet conditions until ca. 5100 cal. a BP, characterized by the deposition of finely laminated organic-carbonatic sediments. In contrast to monsoonal Asia, where a distinct trend towards drier conditions is observed since the mid-Holocene, the hydrologically variable interval at Lake Son Kol was apparently followed by an only short-term dry episode between ca. 5100 and 4200 cal. a BP. This is characterized by a higher δD of the C29 n-alkanes, probably reflecting increased evapotranspiration. Also pollen, diatom and ostracod data point

  4. Here be web proxies

    DEFF Research Database (Denmark)

    Weaver, Nicholas; Kreibich, Christian; Dam, Martin

    2014-01-01

    ,000 clients that include a novel proxy location technique based on traceroutes of the responses to TCP connection establishment requests, which provides additional clues regarding the purpose of the identified web proxies. Overall, we see 14% of Netalyzr-analyzed clients with results that suggest the presence...... of web proxies....

  5. Impact of late glacial climate variations on stratification and trophic state of the meromictic lake Längsee (Austria: validation of a conceptual model by multi proxy studies

    Directory of Open Access Journals (Sweden)

    Jens MÜLLER

    2002-02-01

    Full Text Available Selected pigments, diatoms and diatom-inferred phosphorus (Di-TP concentrations of a late glacial sediment core section of the meromictic Längsee, Austria, were compared with tephra- and varve-dated pollen stratigraphic and geochemical results. A conceptual model was adopted for Längsee and evaluated using multi proxy data. During the unforested late Pleniglacial, a holomictic lake stage with low primary productivity prevailed. Subsequent to the Lateglacial Betula expansion, at about 14,300 cal. y BP, okenone and isorenieratene, pigments from purple and green sulphur bacteria, indicate the onset of anoxic conditions in the hypolimnion. The formation of laminae coincides with this anoxic, meromictic period with high, though fluctuating, amounts of okenone that persisted throughout the Lateglacial interstadial. The occurrence of unlaminated sediment sections of allochthonous origin, and concurrent low concentrations of okenone, were related to cool and wet climate fluctuations during this period, probably coupled with a complete mixing of the water column. Two of these oscillations of the Lateglacial interstadial have been correlated tentatively with the Aegelsee and Gerzensee oscillations in the Alps. The latter climate fluctuation divides a period of enhanced anoxia and primary productivity, correlated with the Alleröd chronozone. Continental climate conditions were assumed to be the main driving forces for meromictic stability during Alleröd times. In addition, calcite dissolution due to severe hypolimnetic anoxia, appear to have supported meromictic stability. Increased pigment concentrations, which are in contrast to low diatom-inferred total phosphorus (Di- TP, indicate the formation of a productive metalimnion during this period, probably due to a clear-water phase (low catchment erosion, increased temperatures, and a steep gradient between the phosphorus enriched hypolimnion and the oligotrophic epilimnion. Meltwater impacts from an

  6. Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059

    Directory of Open Access Journals (Sweden)

    U. Kotthoff

    2017-12-01

    Full Text Available Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial, paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059 over the past  ∼  8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index show that lacustrine conditions occurred in the Little Belt until  ∼  7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer occurred within  ∼  200 years when the connection to the Kattegat became established after  ∼  7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86 can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant

  7. Centennial-scale vegetation and climate changes in the Middle Atlas, Morocco: new insights from multi-proxy investigations at Lake Sidi Ali

    Science.gov (United States)

    Fletcher, William; Campbell, Jennifer; Joannin, Sebastien; Mischke, Steffen; Zielhofer, Christoph; de Batist, Marc; Mikdad, Abdes

    2016-04-01

    The karstic lakes of the Middle Atlas, Morocco, represent a valuable archive of environmental and climatic change for Northwest Africa. Here we present the results of centennial-scale palynological and charcoal analyses as part of a multiproxy palaeolimnological study of sediment cores from Lake Sidi Ali in the Middle Atlas, Morocco (33° 03 N, 05° 00 W; 2,080 m a.s.l.). Supported by absolute dating including 23 more than twenty AMS 14C dates on pollen concentrates, the record covers the entire Holocene and offers insights into vegetation and climate change at a regionally unprecedented centennial-scale. Pollen assemblages are dominated by steppic herbs, evergreen oaks (Quercus), junipers (Cupressaceae) and Atlantic cedar (Cedrus atlantica). A long-term evolution of the montane vegetation is recorded, reflecting progressive changes in the dominant arboreal taxa and leading to the full establishment of the emblematic cedar forests of the area during the mid-Holocene by 6000 cal BP. Orbital-scale changes in seasonality and growing season moisture availability linked to declining summer insolation are implicated, with a transition from (a) warm, dry summers associated with summer drought tolerant taxa especially evergreen Quercus, high algal productivity in the lake, and high background levels of microcharcoal reflecting distant fire activity during the early Holocene, to (b) cool, relatively humid summers with dominance of montane conifers, declining algal productivity in the lake, and episodic local fire activity during the mid- to late Holocene. Superimposed on the long-term environmental changes are recurrent centennial-scale fluctuations in vegetation composition, reflecting competitive dynamics between the major taxa, initially between steppic and arboreal elements, and later between the major tree taxa. Parallels with hydrological proxies including stable O and C isotopes suggest common responses to climatic drivers (fluctuations in moisture sources and

  8. Multi-proxy evidence for compositional change of organic matter in the largest tropical (peninsular) river basin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Pradhan, U.K.; Ying Wu; Shirodkar, P.V.; Zhang, J.; Zhang, G.

    and concentrations of lignin phenols were analyzed in total suspended matter (TSM), sediments, agriculture soils and plants from Godavari basin. The results indicated that the upper tributaries drained heavier carbon (δ13Corg = −20.4 ± 2.2‰) than the lower...

  9. A multi-proxy record from the Quaternary Vienna Basin: Chronology, climate and environmental change at the Alpine-Carpathian transition during the last 250,000 years

    Science.gov (United States)

    Salcher, Bernhard; Lomax, Johanna; Frank, Christa; Preusser, Frank; Scholger, Robert; Ottner, Franz; Wagreich, Michael

    2016-04-01

    Dated multi-proxy records of terrestrial sequences in the Quaternary of the circum-Alpine realm are sparse. This is especially true for those exceeding the time span of the last glacial maximum as extensive glaciers eroded substantial parts of potential records. Outside formerly glaciated regions, preservation space is low in the absence of tectonic subsidence. Foreland terraces forming as a consequence of mountain range uplift may partly account for this gap but are typically dominated by coarse-grained fluvial sediments commonly reflecting only short pulses during cold stage periods. Here we analyze a terrestrial record in the Vienna Basin in order to derive regional climatic and environmental changes of the last c. 250 ka. The Vienna Basin forms as a classical pull-apart feature showing a length of almost 200 km and a width of c. 55 km. Quaternary subsidence is focused along the active Vienna Basin Transfer Fault leading to the formation of a series of narrow strike-slip (sub-) basins and grabens with the Mitterndorf sub-basin being the largest (c. 270 km²) and deepest (c.175 m). The southern part of the basin is confined by the alpine mountain front and fed by two alluvial fans highlighting up to several tens of meters thick coarse grained, massive sediments intercalated by up to few meters thick fine clastic sediments. We investigated the fan's sequence development through core and outcrop sampling applying luminescence dating, magnetostratigraphy, soil and lithofacies classification as well as malacological analysis. The latter comprise the determination and distribution of species and individuals as well as coenological analysis. Data suggest a distinct sequence development with coarse-grained massive sediments abundantly deposited during cold periods (MIS 2 and 6) and fine, overbank sediments and soils, dominantly forming during warmer, Interstadial or Interglacial periods (MIS 5 and 7). Overbanks and soils are generally rich in terrestrial mollusk

  10. 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

    Some of the largest marine environmental impacts from ongoing global climate change are occurring in continental shelf seas and enclosed basins, including severe oxygen depletion, intensifying stratification, and increasing temperatures. In order to predict future changes in water mass conditions, it is essential to reconstruct how these conditions have changed in the past against the background of climate changes. The brackish Baltic Sea is one of the largest semi-enclosed basins worldwide, and its sediment records provide a unique opportunity to analyse palaeo-environmental and climate change in central and northern Europe. IODP Expedition 347 recovered an exceptional set of sediment cores from the Baltic Sea which allow high-resolution reconstructions in unprecedented quality. We present a comparison of commonly-used proxies to reconstruct palaeoecosystems, -temperatures, and -salinity from IODP Site M0059 in the Little Belt over the past ˜8000 years. Our aim is to reconstruct the development of the terrestrial and marine ecosystems in the research area and the related environmental conditions, and to identify potential limitations of individual proxies. The age model for Site M0059 is based on 14Cdating, biostratigraphic correlation with neighbouring terrestrial pollen records, and sediment stratigraphy. Sedimentary organic carbon content and the bulk elemental composition have been measured, and can be used to determine the depositional environment and degree of oxygen depletion (e.g., Mo, Corg/Ptot). Pollen is used as proxy for vegetation development in the hinterland of the southern Baltic Sea and as a land/air-temperature proxy. Comparison with dinoflagellate cysts, insect remains, and green algae remains from the same samples provides a direct land-sea comparison. The application of the modern analogues technique to pollen assemblages has previously yielded precise results for late Pleistocene and Holocene datasets, including specific information on

  11. 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".

  12. Size and emotion or depth and emotion? Evidence, using Matryoshka (Russian) dolls, of children using physical depth as a proxy for emotional charge

    OpenAIRE

    Dunn, AK; Taylor, N; Baguley, T

    2013-01-01

    Background: The size and emotion effect is the tendency for children to draw people and other objects with a positive emotional charge larger than those with a negative or neutral charge. Here we explored the novel idea that drawing size might be acting as a proxy for depth (proximity).Methods: Forty-two children (aged 3-11 years) chose, from 2 sets of Matryoshka (Russian) dolls, a doll to represent a person with positive, negative or neutral charge, which they placed in front of themselves o...

  13. Witnessing entanglement by proxy

    International Nuclear Information System (INIS)

    Bäuml, Stefan; Bruß, Dagmar; Kampermann, Hermann; Huber, Marcus; Winter, Andreas

    2016-01-01

    Entanglement is a ubiquitous feature of low temperature systems and believed to be highly relevant for the dynamics of condensed matter properties and quantum computation even at higher temperatures. The experimental certification of this paradigmatic quantum effect in macroscopic high temperature systems is constrained by the limited access to the quantum state of the system. In this paper we show how macroscopic observables beyond the mean energy of the system can be exploited as proxy witnesses for entanglement detection. Using linear and semi-definite relaxations we show that all previous approaches to this problem can be outperformed by our proxies, i.e. entanglement can be certified at higher temperatures without access to any local observable. For an efficient computation of proxy witnesses one can resort to a generalised grand canonical ensemble, enabling entanglement certification even in complex systems with macroscopic particle numbers. (paper)

  14. Multi-proxy approach (Thorium-234, excess Barium) of export and remineralisation fluxes of carbon and biogenic elements associated with the oceanic biological pump

    International Nuclear Information System (INIS)

    Lemaitre, Nolwenn

    2017-01-01

    The main objective of this thesis is to improve our understanding of the different controls that affect the oceanic biological carbon pump. Particulate export and remineralisation fluxes were investigated using the thorium-234 ( 234 Th) and biogenic barium (Baxs) proxies. In the North Atlantic, the highest particulate organic carbon (POC) export fluxes were associated to biogenic (biogenic silica or calcium carbonate) and lithogenic minerals, ballasting the particles. Export efficiency was generally low (≤ 10%) and inversely related to primary production, highlighting a phase lag between production and export. The highest transfer efficiencies, i.e. the fraction of POC that reached 400 m, were driven by sinking particles ballasted by calcite or lithogenic minerals. The regional variation of meso-pelagic remineralisation was attributed to changes in bloom intensity, phytoplankton cell size, community structure and physical forcing (down-welling). Carbon remineralisation balanced, or even exceeded, POC export, highlighting the impact of meso-pelagic remineralisation on the biological pump with a near-zero, deep carbon sequestration for spring 2014. Export of trace metals appeared strongly influenced by lithogenic material advected from the margins. However, at open ocean stations not influenced by lithogenic matter, trace metal export rather depended on phytoplankton activity and biomass. A last part of this work focused on export of biogenic silica, particulate nitrogen and iron near the Kerguelen Island. This area is characterized by a natural iron-fertilization that increases export fluxes. Inside the fertilized area, flux variability is related to phytoplankton community composition. (author)

  15. Millennial-scale climate variations in western Mediterranean during late Pleistocene-early Holocene: multi-proxy analyses from Padul peatbog (southern Iberian Peninsula)

    Science.gov (United States)

    Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Toney, Jaime L.; Anderson, R. Scott; Kaufman, Darrell; Bright, Jordon; Sachse, Dirk

    2017-04-01

    Padul peatbog, located in southern Iberian Peninsula (western Mediterranean region) is a unique area for palaeoenvironmental studies due to its location, between arid and temperate climates. Previous studies showed that the Padul peatbog contains a continuous record of the last ca. 0.8-1 Ma, so it is an extraordinary site to identify glacial-interglacial phases as well as Heinrich and D-O events, linked to orbital- and suborbital-scale variations. In 2015, a new 42 m long core was taken from this area, providing an excellent sediment record probably for the last ca. 300,000 years. This study is focused on the paleoenvironmental and climatic reconstruction of the late Pleistocene and the early Holocene (ca. from 50,000 to 9,500 cal. yrs BP), using AMS 14C and AAR dating, high-resolution pollen analysis, lithology, continuous XRF-scanning, X-ray diffraction, magnetic susceptibility and organic geochemistry. These different proxies provide information not only about the regional environment change but also about local changes in the conditions of the Padul lake/peatbog due to variations in water temperature, pH or nutrients.

  16. Munchausen by Proxy Syndrome

    Science.gov (United States)

    ... the Child Getting Help for the Parent or Caregiver Print Munchausen by proxy syndrome (MBPS) is a relatively rare form of child abuse that involves the exaggeration or fabrication of illnesses or symptoms by a primary caretaker. Also known as "medical child abuse," MBPS ...

  17. Estimation of sedimentary proxy records together with associated uncertainty

    OpenAIRE

    Goswami, B.; Heitzig, J.; Rehfeld, K.; Marwan, N.; Anoop, A.; Prasad, S.; Kurths, J.

    2014-01-01

    Sedimentary proxy records constitute a significant portion of the recorded evidence that allows us to investigate paleoclimatic conditions and variability. However, uncertainties in the dating of proxy archives limit our ability to fix the timing of past events and interpret proxy record intercomparisons. While there are various age-modeling approaches to improve the estimation of the age–depth relations of archives, relatively little focus has been placed on the propagation...

  18. A multi-proxy lake core record from Lago Lungo, Rieti Basin, Lazio, Italy and its relation to human activities in the catchment during the last century

    Science.gov (United States)

    Noble, Paula; Tunno, Irene; Mensing, Scott; Piovesan, Gianluca

    2016-04-01

    The lakes of the Rieti Basin have experienced extensive human modification dating back to pre-Roman times, yet lake archives indicate that the most profound changes to the aquatic ecosystem have occurred during the last century. Analysis of the upper ˜120 cm segment of a sediment core from Lago Lungo, dating back to ˜1830 CE, show changes in water quality and hydrologic inflow largely attributed to 20th century reclamation and land use activities. Lago Lungo is a shallow, small, eutrophic, hard water lake situated in an intermontaine alluvial plain ˜90 km NE of Rome. It is one of several remnant lakes in a poorly drained wetland area fed by numerous springs. Reclamation activities over the last century have substantially altered the drainage network affecting water delivery to the lakes and their connectivity. There are 3 interesting signals in the core. First, small Stephanodiscus species, associated with hypereutrophic conditions, appear after 1950, peak ˜1990, and may be attributed to increased use of chemical fertilizers and intensification of local agriculture. Elemental proxies from scanning XRF data (abundances of Ti, Si/Ti, and Ca) are consistent with increased eutrophication starting ˜1950. A decline in Stephanodicsus after 1990 reflects some improvement to the water quality following the lake's incorporation into a nature preserve and creation of a narrow vegetation buffer. Intermittent water quality measurements from 1982 onward corroborate the changes in trophic status interpreted from the core record. Second, a large change in the core stratigraphy, elemental geochemistry, and diatom composition occurs ˜1940 and is associated with several major reclamation efforts, including the rerouting of the Santa Susanna channel, which redirected large volumes of artesian inflows away from the lakes and estuarine system. Upstream, dams on the Turano and Salto rivers were also constructed, further affecting hydrological inflows into the basin. From ˜1900

  19. Register of the last 1000 years of environmental, climatic and anthropogenic change in Isla Grande de Chiloé, inferred through a multi-proxy approach: Lake Pastahué, Chile-South Center (42°S)

    Science.gov (United States)

    Troncoso, Jose; Alvarez, Denisse; Díaz, Gustavo; Fierro, Pablo; Araneda, Alberto; Torrejón, Fernando; Rondanelli, Mauricio; Fagel, Nathalie; Urrutia, Roberto

    2017-04-01

    Knowledge of the past environmental and climatic conditions of the lake ecosystems of the Isla Grande de Chiloé and its relationship with the anthropic effect, on a high temporal resolution scale, is scarcely known. Specifically, multi-proxy studies provide a better understanding of the context in which changes occurred in the past. This insular region is particularly interesting because environmental conditions (pre and post-Hispanic) and knowledge about the impacts generated in the ecosystems during the Spanish colonization process have so far been little studied, compared to the rest of Chile continental. This research is a new contribution to the scarce information existing for the last millennium of the Isla Grande de Chiloé. The objective of this work was to reconstruct the environmental and climatic history of the last 1000 years, from the Lake Pastahué, in the Isla Grande de Chiloé through a multi-proxy analysis and compare them with other records for the region. The core sediment was sub-sampled to perform sedimentological analysis (organic matter, carbonates, magnetic susceptibility and granulometry) and biological indicators (pollen, chironomids). The age model was constructed from the activity of 210Pb,137Cs and 14C. The pollen results reveal a composition of nordpatagónico forest represented by Nothofagus, Weinmannia, Drimys, Tepualia, Myrtaceae, Poaceae and Pteridophyta, while the anthropic effect for the last cm of the profile is represented by Rumex and Pinus. The results show a significant increase in magnetic susceptibility since the middle of the 20th century, suggesting an increase in allochthonous material to the lake. The sedimentological parameters and the chironomid assembly show similar variations along the profile, which also shows changes in the trophic state of the lake. The changes recorded in lake Pastahue are directly related to past climatic phenomena occurring in the last millennium, such as the medieval climatic anomaly (MCA

  20. Evaluation of boron isotope ratio as a pH proxy in the deep sea coral Desmophyllum dianthus: Evidence of physiological pH adjustment

    Science.gov (United States)

    Anagnostou, E.; Huang, K.-F.; You, C.-F.; Sikes, E. L.; Sherrell, R. M.

    2012-10-01

    The boron isotope ratio (δ11B) of foraminifers and tropical corals has been proposed to record seawater pH. To test the veracity and practicality of this potential paleo-pH proxy in deep sea corals, samples of skeletal material from twelve archived modern Desmophyllum dianthus (D. dianthus) corals from a depth range of 274-1470 m in the Atlantic, Pacific, and Southern Oceans, ambient pH range 7.57-8.05, were analyzed for δ11B. The δ11B values for these corals, spanning a range from 23.56 to 27.88, are found to be related to seawater borate δ11B by the linear regression: δ11Bcoral=(0.76±0.28) δ11Bborate+(14.67±4.19) (1 standard error (SE)). The D. dianthus δ11B values are greater than those measured in tropical corals, and suggest substantial physiological modification of pH in the calcifying space by a value that is an inverse function of seawater pH. This mechanism partially compensates for the range of ocean pH and aragonite saturation at which this species grows, enhancing aragonite precipitation and suggesting an adaptation mechanism to low pH environments in intermediate and deep waters. Consistent with the findings of Trotter et al. (2011) for tropical surface corals, the data suggest an inverse correlation between the magnitude of a biologically driven pH offset recorded in the coral skeleton, and the seawater pH, described by the equation: ΔpH=pH recorded by coral-seawater pH=-(0.75±0.12) pHw+(6.88±0.93) (1 SE). Error analysis based on 95% confidence interval(CI) and the standard deviation of the regression residuals suggests that the uncertainty of seawater pH reconstructed from δ11Bcoral is ±0.07 to 0.12 pH units. This study demonstrates the applicability of δ11B in D. dianthus to record ambient seawater pH and holds promise for reconstructing oceanic pH distribution and history using fossil corals.

  1. 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

  2. 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.

  3. COMPARATIVE ANALYSIS OF INNOVATION ASPECT EVIDENCE IN CONSTRUCTION AND MULTI-SECTOR COMPANIES

    OpenAIRE

    Ricardo Floriani; Ilse Maria Beuren; Nelson Hein

    2010-01-01

    The goal of this study is to make a comparative analysis of innovation aspect evidence among construction and multi-sector companies. Descriptive research was done through a content analysis of administration reports from 2005 to 2007. From the researched material, 14 aspects of innovations were extracted, which offer the basis to the content analysis. Two non-probability samples were developed, the first consisting of 22 multi-sector businesses, within 18 economic sectors, which comprises th...

  4. A high-elevation, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA

    Science.gov (United States)

    Miller, Ian M.; Pigati, Jeffrey S.; Anderson, R. Scott; Johnson, Kirk R.; Mahan, Shannon; Ager, Thomas A.; Baker, Richard G.; Blaauw, Maarten; Bright, Jordon; Brown, Peter M.; Bryant, Bruce; Calamari, Zachary T.; Carrara, Paul E.; Michael D., Cherney; Demboski, John R.; Elias, Scott A.; Fisher, Daniel C.; Gray, Harrison J.; Haskett, Danielle R.; Honke, Jeffrey S.; Jackson, Stephen T.; Jiménez-Moreno, Gonzalo; Kline, Douglas; Leonard, Eric M.; Lifton, Nathaniel A.; Lucking, Carol; McDonald, H. Gregory; Miller, Dane M.; Muhs, Daniel R.; Nash, Stephen E.; Newton, Cody; Paces, James B.; Petrie, Lesley; Plummer, Mitchell A.; Porinchu, David F.; Rountrey, Adam N.; Scott, Eric; Sertich, Joseph J. W.; Sharpe, Saxon E.; Skipp, Gary L.; Strickland, Laura E.; Stucky, Richard K.; Thompson, Robert S.; Wilson, Jim

    2014-01-01

    In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~ 140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

  5. A high-elevation, multi-proxy biotic and environmental record of MIS 6–4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA

    Energy Technology Data Exchange (ETDEWEB)

    Ian M. Miller; Mitchell A. Plummer; Various Others

    2014-10-01

    In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5

  6. 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 28 ˚ C. In contrast, LDI temperatures were considerably lower and varied only between 21 and 19 ˚ C. MBT'-CBT derived mean annual temperatures for the ages of 9 and 20 Ma align well with the TEX86H SSTs. Overall, the agreement of the paleotemperature proxies in terms of main tendencies, and the covariation with the global benthic oxygen isotope compilation suggests that temperatures in this region varied in concert with global climate variability. The fact that offsets between the different proxies used here remain fairly constant down to 90 Ma ago

  7. A multi-proxy approach to understanding complex responses of salt-lake catchments to climate variability and human pressure: A Late Quaternary case study from south-eastern, Spain

    Science.gov (United States)

    Jones, Samantha Elsie; Burjachs, Francesc; Ferrer-García, Carlos; Giralt, Santiago; Schulte, Lothar; Fernández-López de Pablo, Javier

    2018-03-01

    This article focuses on a former salt lake in the upper Vinalopó Valley in south-eastern Spain. The study spans the Late Pleistocene through to the Late Holocene, although with particular focus on the period between 11 ka cal BP and 3000 ka cal BP (which spans the Mesolithic and part of the Bronze Age). High resolution multi-proxy analysis (including pollen, non pollen palynomorphs, grain size, X-ray fluorescence and X-ray diffraction) was undertaken on the lake sediments. The results show strong sensitivity to both long term and small changes in the evaporation/precipitation ratio, affecting the surrounding vegetation composition, lake-biota and sediment geochemistry. To summarise the key findings the main general trends identified include: 1) Hyper-saline conditions and low lake levels at the end of the Late Glacial 2) Increasing wetness and temperatures which witnessed an expansion of mesophilic woodland taxa, lake infilling and the establishment of a more perennial lake system at the onset of the Holocene 3) An increase in solar insolation after 9 ka cal BP which saw the re-establishment of pine forests 4) A continued trend towards increasing dryness (climatic optimum) at 7 ka cal BP but with continued freshwater input 5) An increase in sclerophyllous open woody vegetation (anthropogenic?), and increasing wetness (climatic?) is represented in the lake record between 5.9 and 3 ka cal BP 6) The Holocene was also punctuated by several aridity pulses, the most prominent corresponding to the 8.2 ka cal BP event. These events, despite a paucity of well dated archaeological sites in the surrounding area, likely altered the carrying capacity of this area both regionally and locally, particularly during the Mesolithic-Neolithic transition, in terms of fresh water supply for human/animal consumption, wild plant food reserves and suitable land for crop growth.

  8. Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

    Science.gov (United States)

    Gałka, Mariusz; Tobolski, Kazimierz; Lamentowicz, Łukasz; Ersek, Vasile; Jassey, Vincent E. J.; van der Knaap, Willem O.; Lamentowicz, Mariusz

    2017-01-01

    We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised bog itself in driving the vegetation and hydrology dynamics. Based on partly synchronous changes in Sphagnum communities in the two study cores we suggest that extrinsic factors (climate) played an important role as a driver in mire development during the bog stage (500-2012 CE). Using a testate amoebae transfer function, we found exceptionally stable hydrological conditions during the last 2000 years with a relatively high water table and lack of local fire events that allowed for rapid peat accumulation (2.75 mm/year) in the bog. Further, the strong correlation between pH and community-weighted mean of testate amoeba traits suggests that other variables than water-table depth play a role in driving microbial properties under stable hydrological conditions. There is a difference in hydrological dynamics in bogs between NW and NE Poland until ca 1500 CE, after which the water table reconstructions show more similarities. Our results illustrate how various functional traits relate to different environmental variables in a range of trophic and hydrological scenarios on long time scales. Moreover, our data suggest a common regional climatic forcing in Mechacz Wielki, Gązwa and Kontolanrahka. Though it may still be too early to attempt a regional summary of wetness change in the southern Baltic region, this study is a next step to better understand the long-term peatland palaeohydrology in NE Europe.

  9. Examining the evidence for a recent acceleration in the rate of sea-level rise using combined instrumental and proxy data, North Carolina, USA

    Science.gov (United States)

    Kemp, A.; Horton, B. P.

    2007-12-01

    Whilst accelerated rates of relative sea-level (RSL) rise are potentially one of the most devastating impacts of future climate change, our understanding of decadal scale changes in sea-level is poor. This paper seeks to address this knowledge gap by combining tide gauge and high-precision geological reconstructions of relative sea-level of sufficient resolution and duration to detect any recent acceleration in the rate of sea-level rise. We offer a high resolution relative sea-level history for the last ~2000 years from the Albemarle - Pamlico Estuarine System in North Carolina. Contemporary foraminifera were collected from five back barrier marshes to create a regional scale modern training set. The use of multiple marshes from a region increases the ecological and environmental diversity included within the training set and reduces the probability of a no modern analogue outcome. To merge the five spatially distinct sites and to relate each to local tide levels we used the VDatum transformation tool. This method relates all samples to a common orthometric datum (NAVD88) and reduces error. We developed an accurate and precise transfer function to reconstruct former sea levels based upon the modern observable relationship between foraminifera and elevation with respect to the tidal frame. We applied the transfer function to salt-marsh core(s) from Sand Point (Roanoke Island), North Carolina to produce a late Holocene RSL record. An age-depth model was produced from composite chronologies of 210Pb, 14C and pollen chrono-horizons. We validated our approach by comparing geological based reconstructions and instrumental tide gauge records. Our records show that in the last ~2000 years sea level has risen at a background rate of ~1.1mm/yr. There is evidence for two recent accelerations in the rate of sea-level rise during the late 19th and 20th centuries to a current rate of ~4mm/yr.

  10. Testing multi-alternative decision models with non-stationary evidence.

    Science.gov (United States)

    Tsetsos, Konstantinos; Usher, Marius; McClelland, James L

    2011-01-01

    Recent research has investigated the process of integrating perceptual evidence toward a decision, converging on a number of sequential sampling choice models, such as variants of race and diffusion models and the non-linear leaky competing accumulator (LCA) model. Here we study extensions of these models to multi-alternative choice, considering how well they can account for data from a psychophysical experiment in which the evidence supporting each of the alternatives changes dynamically during the trial, in a way that creates temporal correlations. We find that participants exhibit a tendency to choose an alternative whose evidence profile is temporally anti-correlated with (or dissimilar from) that of other alternatives. This advantage of the anti-correlated alternative is well accounted for in the LCA, and provides constraints that challenge several other models of multi-alternative choice.

  11. A Weighted Combination Method for Conflicting Evidence in Multi-Sensor Data Fusion

    Directory of Open Access Journals (Sweden)

    Fuyuan Xiao

    2018-05-01

    Full Text Available Dempster–Shafer evidence theory is widely applied in various fields related to information fusion. However, how to avoid the counter-intuitive results is an open issue when combining highly conflicting pieces of evidence. In order to handle such a problem, a weighted combination method for conflicting pieces of evidence in multi-sensor data fusion is proposed by considering both the interplay between the pieces of evidence and the impacts of the pieces of evidence themselves. First, the degree of credibility of the evidence is determined on the basis of the modified cosine similarity measure of basic probability assignment. Then, the degree of credibility of the evidence is adjusted by leveraging the belief entropy function to measure the information volume of the evidence. Finally, the final weight of each piece of evidence generated from the above steps is obtained and adopted to modify the bodies of evidence before using Dempster’s combination rule. A numerical example is provided to illustrate that the proposed method is reasonable and efficient in handling the conflicting pieces of evidence. In addition, applications in data classification and motor rotor fault diagnosis validate the practicability of the proposed method with better accuracy.

  12. COMPARATIVE ANALYSIS OF INNOVATION ASPECT EVIDENCE IN CONSTRUCTION AND MULTI-SECTOR COMPANIES

    Directory of Open Access Journals (Sweden)

    Ricardo Floriani

    2010-12-01

    Full Text Available The goal of this study is to make a comparative analysis of innovation aspect evidence among construction and multi-sector companies. Descriptive research was done through a content analysis of administration reports from 2005 to 2007. From the researched material, 14 aspects of innovations were extracted, which offer the basis to the content analysis. Two non-probability samples were developed, the first consisting of 22 multi-sector businesses, within 18 economic sectors, which comprises the companies in the comparison. Aspects of innovation found in this group of companies were compared to those stated in the reports of the administration of the 34 construction companies with open capital, which comprise the second sample. The survey results show that the evidence of innovation aspects are different in construction companies when compared to the administration reports of multi-sector business of 2005, 2006 and 2007. The construction companies state fewer innovation aspects in the administration reports than multisector companies in the analyzed period. The conclusion is that while construction companies can be considered fairly innovative, multi-sectorial companies present more innovations on average.

  13. A multi-state, multi-site, multi-sector healthcare improvement model: implementing evidence for practice.

    Science.gov (United States)

    Edward, Karen-Leigh; Walker, Kim; Duff, Jed

    2017-10-01

    Healthcare is complex and we know that evidence takes nearly 20 years to find its way into clinical practice. The slow process of translating research points to the need for effective translational research models to ensure patient care quality and safety are not compromised by such an epistemic failure. Our model to achieve reasonably rapid and enduring improvements to clinical care draws on that developed and promulgated by the Institute for Healthcare Improvement in the United States of America model as well as that developed by the Johns Hopkins Quality and Safety Group known as the Translating Research into Practice implementation model. The core principle of our hybrid model was to engage those most likely to be affected by the changes being introduced through a series of face-to-face and web-enabled meetings that act both as drivers of information but also as a means of engaging all stakeholders across the healthcare system involved in the change towards their pre-established goals. The model was piloted on the focused topic of the management of inadvertent perioperative hypothermia across nine hospitals within Australia (four sites in Victoria, three sites in New South Wales and two sites in Queensland). Improvement in management of hypothermia in these patients was achieved and sustained over time. Our model aims to engage the hearts and minds of healthcare clinicians, and others in order to empower them to make the necessary improvements to enhance patient care quality and safety. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  14. The Last Millennium Reanalysis: Improvements to proxies and proxy modeling

    Science.gov (United States)

    Tardif, R.; Hakim, G. J.; Emile-Geay, J.; Noone, D.; Anderson, D. M.

    2017-12-01

    The Last Millennium Reanalysis (LMR) employs a paleoclimate data assimilation (PDA) approach to produce climate field reconstructions (CFRs). Here, we focus on two key factors in PDA generated CFRs: the set of assimilated proxy records and forward models (FMs) used to estimate proxies from climate model output. In the initial configuration of the LMR [Hakim et al., 2016], the proxy dataset of [PAGES2k Consortium, 2013] was used, along with univariate linear FMs calibrated against annually-averaged 20th century temperature datasets. In an updated configuration, proxy records from the recent dataset [PAGES2k Consortium, 2017] are used, while a hierarchy of statistical FMs are tested: (1) univariate calibrated on annual temperature as in the initial configuration, (2) univariate against temperature as in (1) but calibration performed using expert-derived seasonality for individual proxy records, (3) as in (2) but expert proxy seasonality replaced by seasonal averaging determined objectively as part of the calibration process, (4) linear objective seasonal FMs as in (3) but objectively selecting relationships calibrated either on temperature or precipitation, and (5) bivariate linear models calibrated on temperature and precipitation with objectively-derived seasonality. (4) and (5) specifically aim at better representing the physical drivers of tree ring width proxies. Reconstructions generated using the CCSM4 Last Millennium simulation as an uninformed prior are evaluated against various 20th century data products. Results show the benefits of using the new proxy collection, particularly on the detrended global mean temperature and spatial patterns. The positive impact of using proper seasonality and temperature/moisture sensitivities for tree ring width records is also notable. This updated configuration will be used for the first generation of LMR-generated CFRs to be publicly released. These also provide a benchmark for future efforts aimed at evaluating the

  15. Evaluation of patient and proxy responses on the activity measure for postacute care.

    Science.gov (United States)

    Jette, Alan M; Ni, Pengsheng; Rasch, Elizabeth K; Appelman, Jed; Sandel, M Elizabeth; Terdiman, Joseph; Chan, Leighton

    2012-03-01

    Our objective was to examine the agreement between adult patients with stroke and family member or clinician proxies in activity measure for postacute care (AM-PAC) summary scores for daily activity, basic mobility, and applied cognitive function. This study involved 67 patients with stroke admitted to a hospital within the Kaiser Permanente of Northern California system and were participants in a parent study on stroke outcomes. Each participant and proxy respondent completed the AM-PAC by personal or telephone interview at the point of hospital discharge or during ≥1 transitions to different postacute care settings. The results suggest that for patients with a stroke proxy, AM-PAC data are robust for family or clinician proxy assessment of basic mobility function and clinician proxy assessment of daily activity function, but less robust for family proxy assessment of daily activity function and for all proxy groups' assessments of applied cognitive function. The pattern of disagreement between patient and proxy was, on average, relatively small and random. There was little evidence of systematic bias between proxy and patient reports of their functional status. The degree of concordance between patient and proxy was similar for those with moderate to severe strokes compared with mild strokes. Patient and proxy ratings on the AM-PAC achieved adequate agreement for use in stroke research when using proxy respondents could reduce sample selection bias. The AM-PAC data can be implemented across institutional as well as community care settings while achieving precision and reducing respondent burden.

  16. Multi-Sensor Building Fire Alarm System with Information Fusion Technology Based on D-S Evidence Theory

    Directory of Open Access Journals (Sweden)

    Qian Ding

    2014-10-01

    Full Text Available Multi-sensor and information fusion technology based on Dempster-Shafer evidence theory is applied in the system of a building fire alarm to realize early detecting and alarming. By using a multi-sensor to monitor the parameters of the fire process, such as light, smoke, temperature, gas and moisture, the range of fire monitoring in space and time is expanded compared with a single-sensor system. Then, the D-S evidence theory is applied to fuse the information from the multi-sensor with the specific fire model, and the fire alarm is more accurate and timely. The proposed method can avoid the failure of the monitoring data effectively, deal with the conflicting evidence from the multi-sensor robustly and improve the reliability of fire warning significantly.

  17. 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...

  18. A Novel Evidence Theory and Fuzzy Preference Approach-Based Multi-Sensor Data Fusion Technique for Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Fuyuan Xiao

    2017-10-01

    Full Text Available The multi-sensor data fusion technique plays a significant role in fault diagnosis and in a variety of such applications, and the Dempster–Shafer evidence theory is employed to improve the system performance; whereas, it may generate a counter-intuitive result when the pieces of evidence highly conflict with each other. To handle this problem, a novel multi-sensor data fusion approach on the basis of the distance of evidence, belief entropy and fuzzy preference relation analysis is proposed. A function of evidence distance is first leveraged to measure the conflict degree among the pieces of evidence; thus, the support degree can be obtained to represent the reliability of the evidence. Next, the uncertainty of each piece of evidence is measured by means of the belief entropy. Based on the quantitative uncertainty measured above, the fuzzy preference relations are applied to represent the relative credibility preference of the evidence. Afterwards, the support degree of each piece of evidence is adjusted by taking advantage of the relative credibility preference of the evidence that can be utilized to generate an appropriate weight with respect to each piece of evidence. Finally, the modified weights of the evidence are adopted to adjust the bodies of the evidence in the advance of utilizing Dempster’s combination rule. A numerical example and a practical application in fault diagnosis are used as illustrations to demonstrate that the proposal is reasonable and efficient in the management of conflict and fault diagnosis.

  19. Enhancing evidence informed policymaking in complex health systems: lessons from multi-site collaborative approaches.

    Science.gov (United States)

    Langlois, Etienne V; Becerril Montekio, Victor; Young, Taryn; Song, Kayla; Alcalde-Rabanal, Jacqueline; Tran, Nhan

    2016-03-17

    There is an increasing interest worldwide to ensure evidence-informed health policymaking as a means to improve health systems performance. There is a need to engage policymakers in collaborative approaches to generate and use knowledge in real world settings. To address this gap, we implemented two interventions based on iterative exchanges between researchers and policymakers/implementers. This article aims to reflect on the implementation and impact of these multi-site evidence-to-policy approaches implemented in low-resource settings. The first approach was implemented in Mexico and Nicaragua and focused on implementation research facilitated by communities of practice (CoP) among maternal health stakeholders. We conducted a process evaluation of the CoPs and assessed the professionals' abilities to acquire, analyse, adapt and apply research. The second approach, called the Policy BUilding Demand for evidence in Decision making through Interaction and Enhancing Skills (Policy BUDDIES), was implemented in South Africa and Cameroon. The intervention put forth a 'buddying' process to enhance demand and use of systematic reviews by sub-national policymakers. The Policy BUDDIES initiative was assessed using a mixed-methods realist evaluation design. In Mexico, the implementation research supported by CoPs triggered monitoring by local health organizations of the quality of maternal healthcare programs. Health programme personnel involved in CoPs in Mexico and Nicaragua reported improved capacities to identify and use evidence in solving implementation problems. In South Africa, Policy BUDDIES informed a policy framework for medication adherence for chronic diseases, including both HIV and non-communicable diseases. Policymakers engaged in the buddying process reported an enhanced recognition of the value of research, and greater demand for policy-relevant knowledge. The collaborative evidence-to-policy approaches underline the importance of iterations and continuity

  20. On the Nirex MADA [Multi-Attribute Decision Analysis]. Proof of evidence

    International Nuclear Information System (INIS)

    Stirling, A.

    1996-01-01

    Proof of Evidence is given by an expert witness on behalf of Greenpeace Ltd as part of their submission to a Planning Inquiry in 1995 hearing the application of UK Nirex Ltd for permission to construct an underground Rock Characterisation Facility (RCF) at a site near Sellafield. The RCF is part of an investigation by Nirex into a suitable site for the disposal of radioactive waste. The evidence concerns the use by Nirex of a technique known as Multi-Attribute Decision Analysis (MADA) in support of their decision to concentrate their studies on the Sellafield site. Potentially, MADA offers a highly effective methodology for making difficult political decisions involving a mixture of technical, social and economic considerations. Its proper use, however, relies on: drawing an explicit distinction between relatively technical ''performance scores'' and wholly subjective ''importance weightings''; a clearly expressed and agreed scope for the analysis; the inclusion of a wide range of perspectives; systematic and comprehensive sensitivity testing of the implications of varying data, assumptions and value judgements; optimising the choice of option under each perspective; presenting explicit data, assumptions, transparent methodologies and accessible procedures for critical evaluation and public peer review. It is concluded that Nirex's MADA seems to be seriously deficient in relation to many of these principles. (9 references). (UK)

  1. High-resolution, multi-proxy characterization of the event deposit generated by the catastrophic events associated with the Mw 6.2 earthquake of 21 April 2007 in Aysén fjord (Chile)

    Science.gov (United States)

    De Batist, M. A.; Van Daele, M. E.; Cnudde, V.; Duyck, P.; Tjallingii, R. H.; Pino, M.; Urrutia, R.

    2012-12-01

    In 2007, a seismic swarm with more than 7000 recorded earthquakes affected the region around Aysén fjord, Chile (45°25'S). The series of seismic events reached a maximum on 21 April 2007, with an Mw 6.2 earthquake. Intensities as high as VIII to IX on the Modified Mercalli scale were reported around the epicenter. Multiple debris flows, rock slides and rock avalanches were triggered along the fjord's coastline, and several of these caused impact waves or tsunamis with wave heights of up to 6 m, which inundated the fjord shorelines and caused heavy damage and 10 casualties. In order to characterize in detail the imprint left by this series of catastrophic events in the sedimentary record of the fjord, we conducted a multi-disciplinary survey of the inner fjord region in December 2009. Multibeam bathymetry and high-resolution reflection seismic data reveal that large parts of the fjord basin floor, mostly at the foot of the fjord's steep underwater slopes, are covered by recent mass-wasting deposits or consist of mass-wasting-induced deformed basin-plain sediments. A series of short sediment cores collected throughout the inner fjord contain also the more distal deposits of this significant basin-wide mass-wasting event. By combining classical sedimentological techniques (i.e. grain-size analysis, LOI and magnetic susceptibility measurements, all at high resolution) with X-ray CT scanning and XRF scanning we were able to demonstrate that the event deposits encountered in the cores have a very complex signature and actually consist of a succession of several sub-deposits, comprising distal mass-flow deposits from different source areas (as evidenced by XRF-derived geochemical provenance indications) and with a different flow direction (as evidenced by CT-derived 3D flow-direction indications, such as imbricated rip-up mud clasts, cross and convolute laminations) and tsunami- or seiche-generated deposits. This allowed us to reconstruct the succession of sedimentary

  2. Developing a proxy version of the Adult social care outcome toolkit (ASCOT).

    Science.gov (United States)

    Rand, Stacey; Caiels, James; Collins, Grace; Forder, Julien

    2017-05-19

    Social care-related quality of life is a key outcome indicator used in the evaluation of social care interventions and policy. It is not, however, always possible to collect quality of life data by self-report even with adaptations for people with cognitive or communication impairments. A new proxy-report version of the Adult Social Care Outcomes Toolkit (ASCOT) measure of social care-related quality of life was developed to address the issues of wider inclusion of people with cognitive or communication difficulties who may otherwise be systematically excluded. The development of the proxy-report ASCOT questionnaire was informed by literature review and earlier work that identified the key issues and challenges associated with proxy-reported outcomes. To evaluate the acceptability and content validity of the ASCOT-Proxy, qualitative cognitive interviews were conducted with unpaid carers or care workers of people with cognitive or communication impairments. The proxy respondents were invited to 'think aloud' while completing the questionnaire. Follow-up probes were asked to elicit further detail of the respondent's comprehension of the format, layout and content of each item and also how they weighed up the options to formulate a response. A total of 25 unpaid carers and care workers participated in three iterative rounds of cognitive interviews. The findings indicate that the items were well-understood and the concepts were consistent with the item definitions for the standard self-completion version of ASCOT with minor modifications to the draft ASCOT-Proxy. The ASCOT-Proxy allows respondents to rate the proxy-proxy and proxy-patient perspectives, which improved the acceptability of proxy report. A new proxy-report version of ASCOT was developed with evidence of its qualitative content validity and acceptability. The ASCOT-Proxy is ready for empirical testing of its suitability for data collection as a self-completion and/or interview questionnaire, and also

  3. 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

  4. Generalist solutions to complex problems: generating practice-based evidence - the example of managing multi-morbidity

    NARCIS (Netherlands)

    Reeve, J.; Blakeman, T.; Freeman, G.K.; Green, L.A.; James, P.A.; Lucassen, P.L.; Martin, C.M.; Sturmberg, J.P.; Weel, C. van

    2013-01-01

    BACKGROUND: A growing proportion of people are living with long term conditions. The majority have more than one. Dealing with multi-morbidity is a complex problem for health systems: for those designing and implementing healthcare as well as for those providing the evidence informing practice. Yet

  5. Towards a Theory of Managing Wicked Problems through Multi-Stakeholder Engagements: Evidence from the Agribusiness Sector

    NARCIS (Netherlands)

    Dentoni, D.; Ross, R.

    2013-01-01

    Part Two of our Special Issue on wicked problems in agribusiness, “Towards a Theory of Managing Wicked Problems through Multi-Stakeholder Engagements: Evidence from the Agribusiness Sector,” will contribute to four open questions in the broader fields of management and policy: why, when, which and

  6. Generalist solutions to complex problems: generating practice-based evidence--the example of managing multi-morbidity.

    Science.gov (United States)

    Reeve, Joanne; Blakeman, Tom; Freeman, George K; Green, Larry A; James, Paul A; Lucassen, Peter; Martin, Carmel M; Sturmberg, Joachim P; van Weel, Chris

    2013-08-07

    A growing proportion of people are living with long term conditions. The majority have more than one. Dealing with multi-morbidity is a complex problem for health systems: for those designing and implementing healthcare as well as for those providing the evidence informing practice. Yet the concept of multi-morbidity (the presence of >2 diseases) is a product of the design of health care systems which define health care need on the basis of disease status. So does the solution lie in an alternative model of healthcare? Strengthening generalist practice has been proposed as part of the solution to tackling multi-morbidity. Generalism is a professional philosophy of practice, deeply known to many practitioners, and described as expertise in whole person medicine. But generalism lacks the evidence base needed by policy makers and planners to support service redesign. The challenge is to fill this practice-research gap in order to critically explore if and when generalist care offers a robust alternative to management of this complex problem. We need practice-based evidence to fill this gap. By recognising generalist practice as a 'complex intervention' (intervening in a complex system), we outline an approach to evaluate impact using action-research principles. We highlight the implications for those who both commission and undertake research in order to tackle this problem. Answers to the complex problem of multi-morbidity won't come from doing more of the same. We need to change systems of care, and so the systems for generating evidence to support that care. This paper contributes to that work through outlining a process for generating practice-based evidence of generalist solutions to the complex problem of person-centred care for people with multi-morbidity.

  7. Evidence - competence - discourse: the theoretical framework of the multi-centre clinical ethics support project METAP.

    Science.gov (United States)

    Reiter-Theil, Stella; Mertz, Marcel; Schürmann, Jan; Stingelin Giles, Nicola; Meyer-Zehnder, Barbara

    2011-09-01

    In this paper we assume that 'theory' is important for Clinical Ethics Support Services (CESS). We will argue that the underlying implicit theory should be reflected. Moreover, we suggest that the theoretical components on which any clinical ethics support (CES) relies should be explicitly articulated in order to enhance the quality of CES. A theoretical framework appropriate for CES will be necessarily complex and should include ethical (both descriptive and normative), metaethical and organizational components. The various forms of CES that exist in North-America and in Europe show their underlying theory more or less explicitly, with most of them referring to some kind of theoretical components including 'how-to' questions (methodology), organizational issues (implementation), problem analysis (phenomenology or typology of problems), and related ethical issues such as end-of-life decisions (major ethical topics). In order to illustrate and explain the theoretical framework that we are suggesting for our own CES project METAP, we will outline this project which has been established in a multi-centre context in several healthcare institutions. We conceptualize three 'pillars' as the major components of our theoretical framework: (1) evidence, (2) competence, and (3) discourse. As a whole, the framework is aimed at developing a foundation of our CES project METAP. We conclude that this specific integration of theoretical components is a promising model for the fruitful further development of CES. © 2011 Blackwell Publishing Ltd.

  8. A persistent Holocene wetting trend in arid central Asia, with wettest conditions in the late Holocene, revealed by multi-proxy analyses of loess-paleosol sequences in Xinjiang, China

    Science.gov (United States)

    Chen, Fahu; Jia, Jia; Chen, Jianhui; Li, Guoqiang; Zhang, Xiaojian; Xie, Haichao; Xia, Dunsheng; Huang, Wei; An, Chengbang

    2016-08-01

    There are significant differences in the interpretation of the moisture (precipitation) history of arid central Asia (ACA) during the Holocene, as inferred on one hand from speleothem oxygen isotope records, and on the other from lake sediments. Here we present the results of measurements of climatically-sensitive magnetic properties and soil color from four well-dated loess-paleosol sequences from the northern slopes of the Tienshan Mountains and the Yili River valley, Xinjiang, China, in the core area of ACA. Our results demonstrate that the characteristic Holocene paleosol, indicating relatively moist conditions, generally formed after ∼6 ka (1 ka = 1000 cal yr BP) in the study region, and that the accumulation of unweathered loess prevailed during the early Holocene, indicating a dry climate at that time. The magnetic proxies further reveal a trend of generally increasing moisture since the Last Glacial Maximum, with the wettest climate occurring during the late Holocene. This trend of increasing moisture during the Holocene is representative of the Xinjiang region and possibly of the whole of the core area of ACA, and is in marked contrast both to the mid-Holocene moisture maximum observed in the East Asian summer monsoon region and to the general decrease in the strength of the Indian summer monsoon since the early Holocene. Our findings are supported by the results of a climate simulation which indicate a trend of increasing summer and winter precipitation during the Holocene in the core area of ACA, caused mainly by an increase in the strength of the westerlies effected by an increasing latitudinal insolation gradient and by a negative trend of the Arctic Oscillation (AO) or North Atlantic Oscillation (NAO).

  9. Impact of the Little Ice Age cooling and 20th century climate change on peatland vegetation dynamics in central and northern Alberta using a multi-proxy approach and high-resolution peat chronologies

    Science.gov (United States)

    Magnan, Gabriel; van Bellen, Simon; Davies, Lauren; Froese, Duane; Garneau, Michelle; Mullan-Boudreau, Gillian; Zaccone, Claudio; Shotyk, William

    2018-04-01

    Northern boreal peatlands are major terrestrial sinks of organic carbon and these ecosystems, which are highly sensitive to human activities and climate change, act as sensitive archives of past environmental change at various timescales. This study aims at understanding how the climate changes of the last 1000 years have affected peatland vegetation dynamics in the boreal region of Alberta in western Canada. Peat cores were collected from five bogs in the Fort McMurray region (56-57° N), at the southern limit of sporadic permafrost, and two in central Alberta (53° N and 55° N) outside the present-day limit of permafrost peatlands. The past changes in vegetation communities were reconstructed using detailed plant macrofossil analyses combined with high-resolution peat chronologies (14C, atmospheric bomb-pulse 14C, 210Pb and cryptotephras). Peat humification proxies (C/N, H/C, bulk density) and records of pH and ash content were also used to improve the interpretation of climate-related vegetation changes. Our study shows important changes in peatland vegetation and physical and chemical peat properties during the Little Ice Age (LIA) cooling period mainly from around 1700 CE and the subsequent climate warming of the 20th century. In some bogs, the plant macrofossils have recorded periods of permafrost aggradation during the LIA with drier surface conditions, increased peat humification and high abundance of ericaceous shrubs and black spruce (Picea mariana). The subsequent permafrost thaw was characterized by a short-term shift towards wetter conditions (Sphagnum sect. Cuspidata) and a decline in Picea mariana. Finally, a shift to a dominance of Sphagnum sect. Acutifolia (mainly Sphagnum fuscum) occurred in all the bogs during the second half of the 20th century, indicating the establishment of dry ombrotrophic conditions under the recent warmer and drier climate conditions.

  10. Hydroclimate variability in Scandinavia over the last millennium - insights from a climate model-proxy data comparison

    Science.gov (United States)

    Seftigen, Kristina; Goosse, Hugues; Klein, Francois; Chen, Deliang

    2017-12-01

    The integration of climate proxy information with general circulation model (GCM) results offers considerable potential for deriving greater understanding of the mechanisms underlying climate variability, as well as unique opportunities for out-of-sample evaluations of model performance. In this study, we combine insights from a new tree-ring hydroclimate reconstruction from Scandinavia with projections from a suite of forced transient simulations of the last millennium and historical intervals from the CMIP5 and PMIP3 archives. Model simulations and proxy reconstruction data are found to broadly agree on the modes of atmospheric variability that produce droughts-pluvials in the region. Despite these dynamical similarities, large differences between simulated and reconstructed hydroclimate time series remain. We find that the GCM-simulated multi-decadal and/or longer hydroclimate variability is systematically smaller than the proxy-based estimates, whereas the dominance of GCM-simulated high-frequency components of variability is not reflected in the proxy record. Furthermore, the paleoclimate evidence indicates in-phase coherencies between regional hydroclimate and temperature on decadal timescales, i.e., sustained wet periods have often been concurrent with warm periods and vice versa. The CMIP5-PMIP3 archive suggests, however, out-of-phase coherencies between the two variables in the last millennium. The lack of adequate understanding of mechanisms linking temperature and moisture supply on longer timescales has serious implications for attribution and prediction of regional hydroclimate changes. Our findings stress the need for further paleoclimate data-model intercomparison efforts to expand our understanding of the dynamics of hydroclimate variability and change, to enhance our ability to evaluate climate models, and to provide a more comprehensive view of future drought and pluvial risks.

  11. Evidence of late Quaternary wet/dry climate episodes derived from paleoclimatic proxy data recovered from the paleoenvironmental record of the Great Basin of western North America: Paleobotanical studies

    International Nuclear Information System (INIS)

    1998-01-01

    Through the integration of several avenues of paleoclimatic proxy data, the authors intend to arrive a definite conclusions regarding the frequency of periods of wetter climate, and to drive information regarding the magnitudes of these episodes, rates of their onset and demise, and the climatic conditions under which wetter climate can occur. These will in turn lead to rough estimates of: (1) the amounts of rainfall available for recharge during past periods of effectively wetter climate; and (2) the durations and spacing of such events that provide an indication of the amount of time that the area was subjected to these inputs. To accomplish these goals the paleobotanical record over a broad region is being examined to identify periods of greater effective precipitation. Although the project focus is on a region a of about 200 km around Yucca Mountain, they have collected data in other areas of the Great Basin in order to be able to identify large-scale climatic patterns. Once identified and described these climatic patterns can be separated from purely local climatic phenomena that might hinder the understanding of the Pliestocene climates of southern Nevada and the Yucca Mountain area in particular

  12. Climate proxy data as groundwater tracers in regional flow systems

    Science.gov (United States)

    Clark, J. F.; Morrissey, S. K.; Stute, M.

    2008-05-01

    The isotopic and chemical signatures of groundwater reflect local climate conditions. By systematically analyzing groundwater and determining their hydrologic setting, records of past climates can be constructed. Because of their chemistries and relatively uncomplicated source functions, dissolved noble gases have yielded reliable records of continental temperatures for the last 30,000 to 50,000 years. Variations in the stable isotope compositions of groundwater due to long term climate changes have also been documented over these time scales. Because glacial - interglacial climate changes are relatively well known, these climate proxies can be used as "stratigraphic" markers within flow systems and used to distinguish groundwaters that have recharged during the Holocene from those recharged during the last glacial period, important time scales for distinguishing regional and local flow systems in many aquifers. In southern Georgia, the climate proxy tracers were able to identify leakage from surface aquifers into the Upper Floridan aquifer in areas previously thought to be confined. In south Florida, the transition between Holocene and glacial signatures in the Upper Floridan aquifer occurs mid-way between the recharge area and Lake Okeechobee. Down gradient of the lake, the proxies are uniform, indicating recharge during the last glacial period. Furthermore, there is no evidence for leakage from the shallow aquifers into the Upper Floridan. In the Lower Floridan, the climate proxies indicate that the saline water entered the aquifer after sea level rose to its present level.

  13. Host, family and community proxies for infections potentially associated with leukaemia

    International Nuclear Information System (INIS)

    Law, G. R.

    2008-01-01

    Three hypotheses have proposed the involvement of infections in the aetiology of childhood leukaemia, suggesting either a specific leukemogenic infection or a series of common infections that lead to a dys-regulation of the immune system. Much of the evidence for the link with infections has been based on epidemiological observations, often using proxy measures of infection. Proxy measures include population mixing, parental occupation, age distribution of incidence, spatial and space-time clustering of cases, birth order and day care during infancy. This paper discusses the proxies used and examines to what extent a commonly used proxy measure, birth order, is a fair representation of either specific infections or general infectious load. It is clear that although leukaemia, and other diseases, may be linked with infections, one needs to (1) measure specific and general infections with more accuracy and (2) understand how proxy measures relate to real infections in the population. (authors)

  14. Late Holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong, South China

    Science.gov (United States)

    Zhong, Wei; Cao, jiayuan; Xue, Jibin; Ouyang, Jun; Tang, Xiaohong; Yin, Huanling; Liao, Congyun; Long, Kun

    2014-02-01

    The study of a 300-cm-thick exposed lacustrine sediment section in the Hedong village in Zhaoqing area which is located in sub-tropical west Guangdong Province in South China, demonstrates that the lacustrine sedimentary sequence possibly contains evidence for exploring variation of Asian monsoon climate. Multi-proxy records, including the humification intensity, total organic carbon, and grain size fractions, reveal a general trend towards dry and cold conditions in the late Holocene that this is because of a decrease in solar insolation on an orbital scale. Three intensified Asian summer monsoon (ASM) intervals (˜3300-3000 cal yr BP, ˜2600-1600 cal yr BP, and ˜900-600 cal yr BP), and three weakened ASM intervals (˜4000-3300 cal yr BP, ˜3000-2600 cal yr BP, and ˜1600-900 cal yr BP) are identified. Our humification record (HDcal) shows a good correlation on multi-centennial scale with the tree ring Δ14C record, a proxy of solar activity. A spectral analysis of HDcal reveals four significant cycles, i.e., ˜1250 yr, 300 yr, 110 yr, and 70 yr, and most of these cycles are related to the solar activity. Our findings indicate that solar output and oceanic-atmospheric circulation probably have influenced the late Holocene climate variability in the study region.

  15. Paleo-environmental conditions of the Early Cambrian Niutitang Formation in the Fenggang area, the southwestern margin of the Yangtze Platform, southern China: Evidence from major elements, trace elements and other proxies

    Science.gov (United States)

    Li, Jin; Tang, Shuheng; Zhang, Songhang; Xi, Zhaodong; Yang, Ning; Yang, Guoqiao; Li, Lei; Li, Yanpeng

    2018-06-01

    The Precambrian/Cambrian transition was a key time in Earth history, especially for marine biological evolution and oceanic chemistry. The redox-stratification with oxic shallow water and anoxic (even euxinic) deeper water in the Early Cambrian Yangtze Sea, which gradually became completely oxygenated, has been suggested as a possible trigger for the "Cambrian explosion" of biological diversity. However, for some areas in northern Guizhou where the exploration and research are lacking, identifying this pattern of redox-stratification by paleo-environmental analysis from borehole data is still in need. Here, we report a remarkable variation range in trace elements (Mo, V, U, Ni, Th, Co, Sc, Zn and Cu), molar Corg:P ratios and pyrite morphology from 27 core samples from one new drill hole (XY1, located in the Fenggang area, northern Guizhou) on the Yangtze Platform, South China. High levels of Ba (from 3242 ppm to 33,800 ppm) and total organic carbon (TOC; from 4% to 9.36%) in 15 core samples in the Lower Member (LM) of the Niutitang Formation indicated elevated primary productivity in the study area. Redox change was recorded based on enrichment factors (EFs) for RSTEs (Mo, U, and V), redox proxies (V/(V + Ni), Ni/Co, V/Sc and Th/U), Corg:P ratios and particle size of framboidal pyrite. These signatures demonstrate that the LM was deposited under anoxic conditions with sulfidic episodes, whereas the Upper Member (UM) of the Niutitang Formation was deposited under suboxic/oxic conditions with intermittently anoxic episodes. Mo/TOC ratios (from 3.72 to 39.86, mean 18.76) suggest weak-moderate water mass restriction. Mo-U covariation patterns (strong but variable enrichment of Mo and U; MoEF ranging from 31.45 to 257.97; UEF ranging from 4.68 to 39.07) in the LM show alternation of particulate shuttling and redox conditions occurred in the Early Cambrian Yangtze Sea, whereas Mo-U covariation patterns (moderate Mo enrichment but depletion or non-enrichment of U; mean Mo

  16. Empirical evidence for multi-scaled controls on wildfire size distributions in California

    Science.gov (United States)

    Povak, N.; Hessburg, P. F., Sr.; Salter, R. B.

    2014-12-01

    Ecological theory asserts that regional wildfire size distributions are examples of self-organized critical (SOC) systems. Controls on SOC event-size distributions by virtue are purely endogenous to the system and include the (1) frequency and pattern of ignitions, (2) distribution and size of prior fires, and (3) lagged successional patterns after fires. However, recent work has shown that the largest wildfires often result from extreme climatic events, and that patterns of vegetation and topography may help constrain local fire spread, calling into question the SOC model's simplicity. Using an atlas of >12,000 California wildfires (1950-2012) and maximum likelihood estimation (MLE), we fit four different power-law models and broken-stick regressions to fire-size distributions across 16 Bailey's ecoregions. Comparisons among empirical fire size distributions across ecoregions indicated that most ecoregion's fire-size distributions were significantly different, suggesting that broad-scale top-down controls differed among ecoregions. One-parameter power-law models consistently fit a middle range of fire sizes (~100 to 10000 ha) across most ecoregions, but did not fit to larger and smaller fire sizes. We fit the same four power-law models to patch size distributions of aspect, slope, and curvature topographies and found that the power-law models fit to a similar middle range of topography patch sizes. These results suggested that empirical evidence may exist for topographic controls on fire sizes. To test this, we used neutral landscape modeling techniques to determine if observed fire edges corresponded with aspect breaks more often than expected by random. We found significant differences between the empirical and neutral models for some ecoregions, particularly within the middle range of fire sizes. Our results, combined with other recent work, suggest that controls on ecoregional fire size distributions are multi-scaled and likely are not purely SOC. California

  17. 12 CFR 569.4 - Proxy soliciting material.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Proxy soliciting material. 569.4 Section 569.4 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PROXIES § 569.4 Proxy soliciting material. No solicitation of a proxy shall be made by means of any statement, form of proxy...

  18. 12 CFR 569.2 - Form of proxies.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Form of proxies. 569.2 Section 569.2 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PROXIES § 569.2 Form of proxies. Every form of proxy shall conform to the following requirements: (a) The proxy shall be revocable at will by...

  19. Tellurium Stable Isotopes as a Paleoredox Proxy

    Science.gov (United States)

    Wasserman, N.; Johnson, T. M.

    2017-12-01

    Despite arguments for variably-oxygenated shallow waters and anoxic deep marine waters, which delayed animal development until the Neoproterozoic Oxidation Event, the magnitude of atmospheric oxygen during the Proterozoic is still uncertain [1]. The evidence for low pO2 (<0.1-1% PAL) is based on geochemical and isotopic proxies, which track the mobilization of Fe and Mn on the continents. For example, large chromium isotope shifts occur at the Neoproterozoic Oxidation Event due to the initiation of Cr redox cycling, but this proxy is insensitive to fluctuations in the lower-pO2 conditions at other times during the Proterozoic. Tellurium, a metalloid with a lower threshold to oxidation, may be sensitive to pO2 shifts in a lower range. In the reduced forms, Te(-II) and Te(0), the element is insoluble and immobile. However, in the more oxidized phases, Te(IV) and Te(VI), Te can form soluble oxyanions (though it tends to adsorb to Fe-oxyhydroxides and clays) [2]. Te stable isotopes have been shown to fractionate during abiotic or biologic reduction of Te(VI) or Te(IV) to elemental Te(0) [3, 4]. Utilizing hydride generation MC-ICP-MS, we are able to obtain high precision (2σ 0.04‰) measurements of δ128Te/125Te for natural samples containing < 10 ng of Te. A suite of Phanerozoic and Proterozoic ironstones show significant variation in δ128Te/125Te (<0.5‰), suggesting that the Te redox cycle was active during the Proterozoic. Future directions will include Te isotope measurements of Precambrian paleosols to determine natural isotope variation before the Great Oxidation Event and experiments to determine fractionation during adsorption to Fe-oxyhydroxides. [1] Planavsky et al. (2014) Science 346 (6209), pp. 635-638 [2] Qin et al. (2017) Environmental Science and Technology 51 (11), pp 6027-6035 [3] Baesman et al. (2007) Applied Environmental Microbiology 73 (7), pp 2135-2143 [4] Smithers and Krause (1968) Canadian Journal of Chemistry 46(4): pp 583-591

  20. Transparent Proxy for Secure E-Mail

    Science.gov (United States)

    Michalák, Juraj; Hudec, Ladislav

    2010-05-01

    The paper deals with the security of e-mail messages and e-mail server implementation by means of a transparent SMTP proxy. The security features include encryption and signing of transported messages. The goal is to design and implement a software proxy for secure e-mail including its monitoring, administration, encryption and signing keys administration. In particular, we focus on automatic public key on-the-fly encryption and signing of e-mail messages according to S/MIME standard by means of an embedded computer system whose function can be briefly described as a brouter with transparent SMTP proxy.

  1. Robotic Vehicle Proxy Simulation, Phase I

    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...

  2. Summary of the Snowmastodon Project Special Volume. A high-elevation, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA

    Science.gov (United States)

    Miller, Ian M.; Pigati, Jeffrey S.; Scott Anderson, R.; Johnson, Kirk R.; Mahan, Shannon A.; Ager, Thomas A.; Baker, Richard G.; Blaauw, Maarten; Bright, Jordon; Brown, Peter M.; Bryant, Bruce; Calamari, Zachary T.; Carrara, Paul E.; Cherney, Michael D.; Demboski, John R.; Elias, Scott A.; Fisher, Daniel C.; Gray, Harrison J.; Haskett, Danielle R.; Honke, Jeffrey S.; Jackson, Stephen T.; Jiménez-Moreno, Gonzalo; Kline, Douglas; Leonard, Eric M.; Lifton, Nathaniel A.; Lucking, Carol; Gregory McDonald, H.; Miller, Dane M.; Muhs, Daniel R.; Nash, Stephen E.; Newton, Cody; Paces, James B.; Petrie, Lesley; Plummer, Mitchell A.; Porinchu, David F.; Rountrey, Adam N.; Scott, Eric; Sertich, Joseph J. W.; Sharpe, Saxon E.; Skipp, Gary L.; Strickland, Laura E.; Stucky, Richard K.; Thompson, Robert S.; Wilson, Jim

    2014-11-01

    In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean-atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010-2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~ 140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

  3. 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...

  4. Evident?

    DEFF Research Database (Denmark)

    Plant, Peter

    2012-01-01

    Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind......Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind...

  5. Experimental evidence for multi-pass extraction with a bent crystal

    CERN Document Server

    Dehning, Bernd; Fidecaro, Giuseppe; Gyr, Marcel; Herr, Werner; Klem, J T; Scandale, Walter; Vuagnin, G; Weisse, E; Weisz, S; Møller, S P; Uggerhøj, Erik; Freund, A; Hustache, R; Carboni, G; Bussa, M P; Tosello, F

    1996-01-01

    The feasibility of extracting particles from the halo of a circulating proton beam using a bent silicon crystal has been demonstrated experimentally at the SPS for a beam energy of 120 GeV. Presently studies are conducted to understand the extraction mechanisms and the measured efficiencies. In particular the contribution of multi-pass extraction, where the particles can pass through the crystal many times before being channelled and extracted, is investigated. In a recent experiment, using a crystal especially fabricated with a finite amorphous layer on its surface, it has been proven that multi-pass extraction plays an important role. The experiment is described and the implication for further studies are discussed.

  6. Testing a model of componential processing of multi-symbol numbers-evidence from measurement units.

    Science.gov (United States)

    Huber, Stefan; Bahnmueller, Julia; Klein, Elise; Moeller, Korbinian

    2015-10-01

    Research on numerical cognition has addressed the processing of nonsymbolic quantities and symbolic digits extensively. However, magnitude processing of measurement units is still a neglected topic in numerical cognition research. Hence, we investigated the processing of measurement units to evaluate whether typical effects of multi-digit number processing such as the compatibility effect, the string length congruity effect, and the distance effect are also present for measurement units. In three experiments, participants had to single out the larger one of two physical quantities (e.g., lengths). In Experiment 1, the compatibility of number and measurement unit (compatible: 3 mm_6 cm with 3 mm) as well as string length congruity (congruent: 1 m_2 km with m 2 characters) were manipulated. We observed reliable compatibility effects with prolonged reaction times (RT) for incompatible trials. Moreover, a string length congruity effect was present in RT with longer RT for incongruent trials. Experiments 2 and 3 served as control experiments showing that compatibility effects persist when controlling for holistic distance and that a distance effect for measurement units exists. Our findings indicate that numbers and measurement units are processed in a componential manner and thus highlight that processing characteristics of multi-digit numbers generalize to measurement units. Thereby, our data lend further support to the recently proposed generalized model of componential multi-symbol number processing.

  7. Detecting instabilities in tree-ring proxy calibration

    Directory of Open Access Journals (Sweden)

    H. Visser

    2010-06-01

    Full Text Available Evidence has been found for reduced sensitivity of tree growth to temperature in a number of forests at high northern latitudes and alpine locations. Furthermore, at some of these sites, emergent subpopulations of trees show negative growth trends with rising temperature. These findings are typically referred to as the "Divergence Problem" (DP. Given the high relevance of paleoclimatic reconstructions for policy-related studies, it is important for dendrochronologists to address this issue of potential model uncertainties associated with the DP. Here we address this issue by proposing a calibration technique, termed "stochastic response function" (SRF, which allows the presence or absence of any instabilities in growth response of trees (or any other climate proxy to their calibration target to be visualized and detected. Since this framework estimates confidence limits and subsequently provides statistical significance tests, the approach is also very well suited for proxy screening prior to the generation of a climate-reconstruction network.

    Two examples of tree growth/climate relationships are provided, one from the North American Arctic treeline and the other from the upper treeline in the European Alps. Instabilities were found to be present where stabilities were reported in the literature, and vice versa, stabilities were found where instabilities were reported. We advise to apply SRFs in future proxy-screening schemes, next to the use of correlations and RE/CE statistics. It will improve the strength of reconstruction hindcasts.

  8. 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.

  9. Evidence-informed health policy 1 - synthesis of findings from a multi-method study of organizations that support the use of research evidence.

    Science.gov (United States)

    Lavis, John N; Oxman, Andrew D; Moynihan, Ray; Paulsen, Elizabeth J

    2008-12-17

    Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs). We undertook a multi-method study in three phases - a survey, interviews, and case descriptions that drew on site visits - and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1) collaborate with other organizations; 2) establish strong links with policymakers and involve stakeholders in the work; 3) be independent and manage conflicts of interest among those involved in the work; 4) build capacity among those working in the organization; 5) use good methods and be transparent in the work; 6) start small, have a clear audience and scope, and address important questions; and 7) be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO) and other international organizations and networks: 1) support collaborations among organizations; 2) support local adaptation efforts; 3) mobilize support; and 4) create global public goods. This synthesis of

  10. Evidence-informed health policy 1 – Synthesis of findings from a multi-method study of organizations that support the use of research evidence

    Directory of Open Access Journals (Sweden)

    Moynihan Ray

    2008-12-01

    Full Text Available Abstract Background Organizations have been established in many countries and internationally to support the use of research evidence by producing clinical practice guidelines, undertaking health technology assessments, and/or directly supporting the use of research evidence in developing health policy on an international, national, and state or provincial level. Learning from these organizations can reduce the need to 'reinvent the wheel' and inform decisions about how best to organize support for such organizations, particularly in low- and middle-income countries (LMICs. Methods We undertook a multi-method study in three phases – a survey, interviews, and case descriptions that drew on site visits – and in each of the second and third phases we focused on a purposive sample of those involved in the previous phase. We used the seven main recommendations that emerged from the advice offered in the interviews to organize much of the synthesis of findings across phases and methods. We used a constant comparative method to identify themes from across phases and methods. Results Seven recommendations emerged for those involved in establishing or leading organizations that support the use of research evidence in developing health policy: 1 collaborate with other organizations; 2 establish strong links with policymakers and involve stakeholders in the work; 3 be independent and manage conflicts of interest among those involved in the work; 4 build capacity among those working in the organization; 5 use good methods and be transparent in the work; 6 start small, have a clear audience and scope, and address important questions; and 7 be attentive to implementation considerations, even if implementation is not a remit. Four recommendations emerged for the World Health Organization (WHO and other international organizations and networks: 1 support collaborations among organizations; 2 support local adaptation efforts; 3 mobilize support; and 4 create

  11. Global Tsunami Database: Adding Geologic Deposits, Proxies, and Tools

    Science.gov (United States)

    Brocko, V. R.; Varner, J.

    2007-12-01

    A result of collaboration between NOAA's National Geophysical Data Center (NGDC) and the Cooperative Institute for Research in the Environmental Sciences (CIRES), the Global Tsunami Database includes instrumental records, human observations, and now, information inferred from the geologic record. Deep Ocean Assessment and Reporting of Tsunamis (DART) data, historical reports, and information gleaned from published tsunami deposit research build a multi-faceted view of tsunami hazards and their history around the world. Tsunami history provides clues to what might happen in the future, including frequency of occurrence and maximum wave heights. However, instrumental and written records commonly span too little time to reveal the full range of a region's tsunami hazard. The sedimentary deposits of tsunamis, identified with the aid of modern analogs, increasingly complement instrumental and human observations. By adding the component of tsunamis inferred from the geologic record, the Global Tsunami Database extends the record of tsunamis backward in time. Deposit locations, their estimated age and descriptions of the deposits themselves fill in the tsunami record. Tsunamis inferred from proxies, such as evidence for coseismic subsidence, are included to estimate recurrence intervals, but are flagged to highlight the absence of a physical deposit. Authors may submit their own descriptions and upload digital versions of publications. Users may sort by any populated field, including event, location, region, age of deposit, author, publication type (extract information from peer reviewed publications only, if you wish), grain size, composition, presence/absence of plant material. Users may find tsunami deposit references for a given location, event or author; search for particular properties of tsunami deposits; and even identify potential collaborators. Users may also download public-domain documents. Data and information may be viewed using tools designed to extract and

  12. [Validity and reliability of the spanish EQ-5D-Y proxy version].

    Science.gov (United States)

    Gusi, N; Perez-Sousa, M A; Gozalo-Delgado, M; Olivares, P R

    2014-10-01

    A proxy version of the EQ-5D-Y, a questionnaire to evaluate the Health Related Quality of Life (HRQoL) in children and adolescents, has recently been developed. There are currently no data on the validity and reliability of this tool. The objective of this study was to analyze the validity and reliability of the EQ-5D-Y proxy version. A core set of self-report tools, including the Spanish version of the EQ-5D-Y were administered to a group of Spanish children and adolescents drawn from the general population. A similar core set of internationally standardized proxy tools, including the EQ-5D-Y proxy version were administered to their parents. Test-retest reliability was determined, and correlations with other generic measurements of HRQoL were calculated. Additionally, known group validity was examined by comparing groups with a priori expected differences in HRQoL. The agreement between the self-report and proxy version responses was also calculated. A total of 477 children and adolescents and their parents participated in the study. One week later, 158 participants completed the EQ-5D-Y/EQ-5D-Y proxy to facilitate reliability analysis. Agreement between the test-retest scores was higher than 88% for EQ-5D-Y self-report, and proxy version. Correlations with other health measurements showed similar convergent validity to that observed in the international EQ-5D-Y. Agreement between the self-report and proxy versions ranged from 72.9% to 97.1%. The results provide preliminary evidence of the reliability and validity of the EQ-5D-Y proxy version. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  13. A Guide to Visual Multi-Level Interface Design From Synthesis of Empirical Study Evidence

    CERN Document Server

    Lam, Heidi

    2010-01-01

    Displaying multiple levels of data visually has been proposed to address the challenge of limited screen space. Although many previous empirical studies have addressed different aspects of this question, the information visualization research community does not currently have a clearly articulated consensus on how, when, or even if displaying data at multiple levels is effective. To shed more light on this complex topic, we conducted a systematic review of 22 existing multi-level interface studies to extract high-level design guidelines. To facilitate discussion, we cast our analysis findings

  14. 12 CFR 569.3 - Holders of proxies.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Holders of proxies. 569.3 Section 569.3 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY PROXIES § 569.3 Holders of proxies. No proxy of a mutual savings association with a term greater than eleven months or solicited at...

  15. Water Isotope Proxy-Proxy and Proxy-Model Convergence for Late Pleistocene East Asian Monsoon Rainfall Reconstructions

    Science.gov (United States)

    Clemens, S. C.; Holbourn, A.; Kubota, Y.; Lee, K. E.; Liu, Z.; Chen, G.

    2017-12-01

    Confidence in reconstruction of East Asian paleomonsoon rainfall using precipitation isotope proxies is a matter of considerable debate, largely due to the lack of correlation between precipitation amount and isotopic composition in the present climate. We present four new, very highly resolved records spanning the past 300,000 years ( 200 year sample spacing) from IODP Site U1429 in the East China Sea. We demonstrate that all the orbital- and millennial-scale variance in the onshore Yangtze River Valley speleothem δ18O record1 is also embedded in the offshore Site U1429 seawater δ18O record (derived from the planktonic foraminifer Globigerinoides ruber and sea surface temperature reconstructions). Signal replication in these two independent terrestrial and marine archives, both controlled by the same monsoon system, uniquely identifies δ18O of precipitation as the primary driver of the precession-band variance in both records. This proxy-proxy convergence also eliminates a wide array of other drivers that have been called upon as potential contaminants to the precipitation δ18O signal recorded by these proxies. We compare East Asian precipitation isotope proxy records to precipitation amount from a CCSM3 transient climate model simulation of the past 300,000 years using realistic insolation, ice volume, greenhouse gasses, and sea level boundary conditions. This model-proxy comparison suggests that both Yangtze River Valley precipitation isotope proxies (seawater and speleothem δ18O) track changes in summer-monsoon rainfall amount at orbital time scales, as do precipitation isotope records from the Pearl River Valley2 (leaf wax δ2H) and Borneo3 (speleothem δ18O). Notably, these proxy records all have significantly different spectral structure indicating strongly regional rainfall patterns that are also consistent with model results. Transient, isotope-enabled model simulations will be necessary to more thoroughly evaluate these promising results, and to

  16. Probability Judgements in Multi-Stage Problems : Experimental Evidence of Systematic Biases

    NARCIS (Netherlands)

    Gneezy, U.

    1996-01-01

    We report empirical evidence that in problems of random walk with positive drift, bounded rationality leads individuals to under-estimate the probability of success in the long run.In particular, individuals who were given the stage by stage probability distribution failed to aggregate this

  17. Medieval Horse Stable; The Results of Multi Proxy Interdisciplinary Research

    Czech Academy of Sciences Publication Activity Database

    Dejmal, M.; Lisá, Lenka; Nývltová Fišáková, Miriam; Bajer, A.; Petr, Libor; Kočár, P.; Kočárová, R.; Nejman, L.; Rybníček, M.; Sůvová, Z.; Culp, R.; Vavrčík, H.

    2014-01-01

    Roč. 9, č. 3 (2014) E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GAP405/11/1729 Institutional support: RVO:67985831 ; RVO:68081758 Keywords : carbon isotopes * tail- hair * diet * sediments * turnover * Iceland * England * houses Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 3.234, year: 2014

  18. Multi-proxy monitoring approaches at Kangaroo Island, South Australia

    Science.gov (United States)

    Dixon, Bronwyn; Drysdale, Russell; Tyler, Jonathan; Goodwin, Ian

    2017-04-01

    Interpretations of geochemical signals preserved in young speleothems are greatly enhanced by comprehensive cave-site monitoring. In the light of this, a cave monitoring project is being conducted concurrently with the development of a new palaeoclimate record from Kelly Hill Cave (Kangaroo Island, South Australia). The site is strategically located because it is situated between longer-lived monitoring sites in southeastern and southwestern Australia, as well as being climatically 'upstream' from major population and agricultural centres. This study aims to understand possible controls on speleothem δ18O in Kelly Hill Cave through i. identification of local and regional δ18O drivers in precipitation; and ii. preservation and modification of climatic signals within the epikarst as indicated by dripwater δ18O. These aims are achieved through analysis of a five-year daily rainfall (amount and δ18O) dataset in conjunction with in-cave drip monitoring. Drivers of precipitation δ18O were identified through linear regression between δ18O values and local meteorological variables, air-parcel back trajectories, and synoptic-typing. Synoptically driven moisture sources were identified through the use of NCEP/NCAR climate reanalysis sea-level pressure, precipitable moisture, and outgoing longwave radiation data in order to trace moisture sources and travel mechanisms from surrounding ocean basins. Local controls on δ18O at Kelly Hill Cave are consistent with published interpretations of southern Australia sites, with oxygen isotopes primarily controlled by rainfall amount on both daily and monthly time scales. Back-trajectory analysis also supports previous observations that the Southern Ocean is the major source for moisture-bearing cold-front systems. However, synoptic typing of daily rainfall δ18O and amount extremes reveals a previously unreported tropical connection and moisture source. This tropical connection appears to be strongest in summer and autumn, but exists throughout the year. This indicates that a wider range of precipitation data sources can be combined to present a more comprehensive understanding of moisture dynamics and interaction of synoptic conditions to drive rainfall geochemistry. Within the cave environment at Kelly Hill Cave there is high spatial variability in drip characteristics, both in terms of drip frequency and drip water δ18O. Ongoing analyses are aimed at determining if monthly and/or seasonal rainfall δ18O drivers are also reflected in dripwater values. Overall, Kangaroo Island presents a new location to investigate the interplay between tropical and temperate influences in southern Australia, as well as a location for east - west comparisons between monitoring sites across southern Australia.

  19. Experimental evidence of hot carriers solar cell operation in multi-quantum wells heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Rodière, Jean; Lombez, Laurent, E-mail: laurent.lombez@chimie-paristech.fr [IRDEP, Institute of R and D on Photovoltaic Energy, UMR 7174, CNRS-EDF-Chimie ParisTech, 6 Quai Watier-BP 49, 78401 Chatou Cedex (France); Le Corre, Alain; Durand, Olivier [INSA, FOTON-OHM, UMR 6082, F-35708 Rennes (France); Guillemoles, Jean-François [IRDEP, Institute of R and D on Photovoltaic Energy, UMR 7174, CNRS-EDF-Chimie ParisTech, 6 Quai Watier-BP 49, 78401 Chatou Cedex (France); NextPV, LIA CNRS-RCAST/U. Tokyo-U. Bordeaux, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-05-04

    We investigated a semiconductor heterostructure based on InGaAsP multi quantum wells (QWs) using optical characterizations and demonstrate its potential to work as a hot carrier cell absorber. By analyzing photoluminescence spectra, the quasi Fermi level splitting Δμ and the carrier temperature are quantitatively measured as a function of the excitation power. Moreover, both thermodynamics values are measured at the QWs and the barrier emission energy. High values of Δμ are found for both transition, and high carrier temperature values in the QWs. Remarkably, the quasi Fermi level splitting measured at the barrier energy exceeds the absorption threshold of the QWs. This indicates a working condition beyond the classical Shockley-Queisser limit.

  20. Fighting terrorism in Africa by proxy

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2014-01-01

    The French intervention in Mali in early 2013 emphasizes that the decision-makers in Paris, Brussels, and Washington considered the establishment of the radical Islamist regime in Northern Mali a threat to their security interests. The widespread instability including the rise of radical Islamist...... groups in Somalia was perceived as a threat to western interests. It is the core argument of the paper if western powers decide to provide security in Africa, they will be inclined to use proxy instead of deploying own troops. Security provision by proxy in African means that African troops are doing...

  1. 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

  2. PROCESSING OF MULTI-DIGIT ADDITIONS IN HIGH MATH-ANXIOUS INDIVIDUALS: PSYCHOPHYSIOLOGICAL EVIDENCE

    Directory of Open Access Journals (Sweden)

    MARIA ISABEL eNÚÑEZ-PEÑA

    2015-08-01

    Full Text Available We investigated the time course of neural processing of multi-digit additions in high- (HMA and low-math anxious (LMA individuals. Seventeen HMA and 17 LMA individuals were presented with two-digit additions and were asked to perform a verification task. Behavioral data showed that HMA were slower and more error prone than their LMA peers, and that incorrect solutions were solved more slowly and less accurately than correct ones. Moreover, HMA individuals tended to need more time and commit more errors when having to verify incorrect solutions than correct ones. They also took longer and made more errors than their LMA peers. ERPs time-locked to the presentation of the addends (calculation phase and to the presentation of the proposed solution (verification phase were also analyzed. In both phases, a P2 component of larger amplitude was found for HMA individuals than for their LMA peers. Moreover, in the verification phase, LMA individuals showed a larger late positive component (LPC for incorrect solutions at parietal electrodes than their HMA counterparts. Because the P2 component is considered to be a biomarker of the mobilization of attentional resources towards emotionally negative stimuli, these results suggest that HMA individuals may invest more attentional resources during the arithmetical

  3. Validation of a proxy for estrogen receptor status in breast cancer patients using dispensing data.

    Science.gov (United States)

    Srasuebkul, Preeyaporn; Dobbins, Timothy A; Pearson, Sallie-Anne

    2014-06-01

    To assess the performance of a proxy for estrogen receptor (ER) status in breast cancer patients using dispensing data. We derived our proxy using 167 patients. ER+ patients had evidence of at least one dispensing record for hormone therapy during the lookback period, irrespective of diagnosis date and ER- had no dispensing records for hormone therapy during the period. We validated the proxy against our gold standard, ER status from pathology reports or medical records. We assessed the proxy's performance using three lookback periods: 4.5 years, 2 years, 1 year. More than half of our cohort (62%) were >50 years, 54% had stage III/IV breast cancer at recruitment, (46%) were diagnosed with breast cancer in 2009 and 23% were diagnosed before 2006. Sensitivity and specificity were high for the 4.5 year lookback period (93%, 95% CI: 86-96%; and 95%: 83-99%), respectively) and remained high for the 2-year lookback period (91%: 84-95%; and 95%: 83-99%). Sensitivity decreased (83%: 75.2-89%) but specificity remained high (95%: 83-99%) using the 1-year lookback period and the period is long enough to allow sufficient time for hormone therapy to be dispensed. Our proxy accurately infers ER status in studies of breast cancer treatment based on secondary health data. The proxy is most robust with a minimum lookback period of 2 years. © 2012 Wiley Publishing Asia Pty Ltd.

  4. 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)

  5. 78 FR 70987 - Proxy Advisory Firm Roundtable

    Science.gov (United States)

    2013-11-27

    ... Firm Roundtable AGENCY: Securities and Exchange Commission. ACTION: Notice of roundtable discussion... advisory firms. The panel will be asked to discuss topics including the current state of proxy advisory firm use by investment advisers and institutional investors and potential changes that have been...

  6. Munchausen syndrome by proxy: a family anthology.

    Science.gov (United States)

    Pickford, E; Buchanan, N; McLaughlan, S

    1988-06-20

    While the Munchausen-by-proxy syndrome is well recognized, the story of one family has been related to describe some remarkable features. These include the psychopathology of the mother, the involvement of both children in the family, the great difficulty in obtaining proof of child abuse and, finally, the prosecution of the mother in the criminal court.

  7. The Proxy Challenge: Why bespoke proxy indicators can help solve the anti-corruption measurement problem

    OpenAIRE

    Johnsøn, Jesper; Mason, Phil

    2013-01-01

    Practitioners working in anti-corruption face perennial challenges in measuring changes in corruption levels and evaluating whether anti-corruption efforts are successful. These two challenges are linked but not inseparable. To make progress on the latter front, that is, evaluating whether anti-corruption efforts are having an impact, the U4 Anti-Corruption Resource Centre and the UK Department for International Development are launching an exploration into the use of proxy indicators. Proxy ...

  8. Bridging the data gaps in the epidemiology of hepatitis C virus infection in Malaysia using multi-parameter evidence synthesis.

    Science.gov (United States)

    McDonald, Scott A; Mohamed, Rosmawati; Dahlui, Maznah; Naning, Herlianna; Kamarulzaman, Adeeba

    2014-11-07

    Collecting adequate information on key epidemiological indicators is a prerequisite to informing a public health response to reduce the impact of hepatitis C virus (HCV) infection in Malaysia. Our goal was to overcome the acute data shortage typical of low/middle income countries using statistical modelling to estimate the national HCV prevalence and the distribution over transmission pathways as of the end of 2009. Multi-parameter evidence synthesis methods were applied to combine all available relevant data sources - both direct and indirect - that inform the epidemiological parameters of interest. An estimated 454,000 (95% credible interval [CrI]: 392,000 to 535,000) HCV antibody-positive individuals were living in Malaysia in 2009; this represents 2.5% (95% CrI: 2.2-3.0%) of the population aged 15-64 years. Among males of Malay ethnicity, for 77% (95% CrI: 69-85%) the route of probable transmission was active or a previous history of injecting drugs. The corresponding proportions were smaller for male Chinese and Indian/other ethnic groups (40% and 71%, respectively). The estimated prevalence in females of all ethnicities was 1% (95% CrI: 0.6 to 1.4%); 92% (95% CrI: 88 to 95%) of infections were attributable to non-drug injecting routes of transmission. The prevalent number of persons living with HCV infection in Malaysia is estimated to be very high. Low/middle income countries often lack a comprehensive evidence base; however, evidence synthesis methods can assist in filling the data gaps required for the development of effective policy to address the future public health and economic burden due to HCV.

  9. 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....

  10. Harvard Law School Proxy Access Roundtable

    OpenAIRE

    Bebchuk, Lucian Arye; Hirst, Scott

    2010-01-01

    This paper contains the proceedings of the Proxy Access Roundtable that was held by the Harvard Law School Program on Corporate Governance on October 7, 2009. The Roundtable brought together prominent participants in the debate - representing a range of perspectives and experiences - for a day of discussion on the subject. The day’s first two sessions focused on the question of whether the Securities and Exchange Commission should provide an access regime, or whether it should leave the adopt...

  11. Munchausen syndrome by proxy and child's rights

    International Nuclear Information System (INIS)

    Al-Haidar, Fatima A.

    2008-01-01

    Munchausen syndrome by proxy (MSBP) is an extreme form of child abuse in which perpetrators induce life-threatening conditions in their children. A case of MSBP is described in detail. Difficulties in diagnosis and management in this part of the world are presented. Until now, no national legal guidelines exist in the Kingdom of Saudi Arabia (KSA) to child abuse in general and MSBP in particular. Urgent guidelines, policies and legal system are required in the KSA. (author)

  12. Forecasting Lightning Threat Using WRF Proxy Fields

    Science.gov (United States)

    McCaul, E. W., Jr.

    2010-01-01

    Objectives: Given that high-resolution WRF forecasts can capture the character of convective outbreaks, we seek to: 1. Create WRF forecasts of LTG threat (1-24 h), based on 2 proxy fields from explicitly simulated convection: - graupel flux near -15 C (captures LTG time variability) - vertically integrated ice (captures LTG threat area). 2. Calibrate each threat to yield accurate quantitative peak flash rate densities. 3. Also evaluate threats for areal coverage, time variability. 4. Blend threats to optimize results. 5. Examine sensitivity to model mesh, microphysics. Methods: 1. Use high-resolution 2-km WRF simulations to prognose convection for a diverse series of selected case studies. 2. Evaluate graupel fluxes; vertically integrated ice (VII). 3. Calibrate WRF LTG proxies using peak total LTG flash rate densities from NALMA; relationships look linear, with regression line passing through origin. 4. Truncate low threat values to make threat areal coverage match NALMA flash extent density obs. 5. Blend proxies to achieve optimal performance 6. Study CAPS 4-km ensembles to evaluate sensitivities.

  13. Recalibrating Baseline Evidence in Burundi, Malawi, Senegal and Uganda: Exploring the Potential of Multi-Site, National-Level Stakeholder Engagement in Participatory Evaluation

    Science.gov (United States)

    Edge, Karen; Marphatia, Akanksha A.

    2015-01-01

    This paper details our collaborative work on the Improving Learning Outcomes in Primary Schools (ILOPS) project in Burundi, Malawi, Uganda and Senegal. ILOPS set out to establish an innovative template for multi-stakeholder, multinational participatory evaluation (PE) and examine the fundamental roles, relationships and evidence that underpin the…

  14. Optimizing suicide prevention programs and their implementation in Europe (OSPI Europe): an evidence-based multi-level approach.

    LENUS (Irish Health Repository)

    Hegerl, Ulrich

    2009-01-01

    BACKGROUND: Suicide and non-fatal suicidal behaviour are significant public health issues in Europe requiring effective preventive interventions. However, the evidence for effective preventive strategies is scarce. The protocol of a European research project to develop an optimized evidence based program for suicide prevention is presented. METHOD: The groundwork for this research has been established by a regional community based intervention for suicide prevention that focuses on improving awareness and care for depression performed within the European Alliance Against Depression (EAAD). The EAAD intervention consists of (1) training sessions and practice support for primary care physicians,(2) public relations activities and mass media campaigns, (3) training sessions for community facilitators who serve as gatekeepers for depressed and suicidal persons in the community and treatment and (4) outreach and support for high risk and self-help groups (e.g. helplines). The intervention has been shown to be effective in reducing suicidal behaviour in an earlier study, the Nuremberg Alliance Against Depression. In the context of the current research project described in this paper (OSPI-Europe) the EAAD model is enhanced by other evidence based interventions and implemented simultaneously and in standardised way in four regions in Ireland, Portugal, Hungary and Germany. The enhanced intervention will be evaluated using a prospective controlled design with the primary outcomes being composite suicidal acts (fatal and non-fatal), and with intermediate outcomes being the effect of training programs, changes in public attitudes, guideline-consistent media reporting. In addition an analysis of the economic costs and consequences will be undertaken, while a process evaluation will monitor implementation of the interventions within the different regions with varying organisational and healthcare contexts. DISCUSSION: This multi-centre research seeks to overcome major

  15. Optimizing suicide prevention programs and their implementation in Europe (OSPI-Europe): An evidence-based multi-level approach

    LENUS (Irish Health Repository)

    Hegerl, Ulrich

    2009-11-23

    Abstract Background Suicide and non-fatal suicidal behaviour are significant public health issues in Europe requiring effective preventive interventions. However, the evidence for effective preventive strategies is scarce. The protocol of a European research project to develop an optimized evidence based program for suicide prevention is presented. Method The groundwork for this research has been established by a regional community based intervention for suicide prevention that focuses on improving awareness and care for depression performed within the European Alliance Against Depression (EAAD). The EAAD intervention consists of (1) training sessions and practice support for primary care physicians,(2) public relations activities and mass media campaigns, (3) training sessions for community facilitators who serve as gatekeepers for depressed and suicidal persons in the community and treatment and (4) outreach and support for high risk and self-help groups (e.g. helplines). The intervention has been shown to be effective in reducing suicidal behaviour in an earlier study, the Nuremberg Alliance Against Depression. In the context of the current research project described in this paper (OSPI-Europe) the EAAD model is enhanced by other evidence based interventions and implemented simultaneously and in standardised way in four regions in Ireland, Portugal, Hungary and Germany. The enhanced intervention will be evaluated using a prospective controlled design with the primary outcomes being composite suicidal acts (fatal and non-fatal), and with intermediate outcomes being the effect of training programs, changes in public attitudes, guideline-consistent media reporting. In addition an analysis of the economic costs and consequences will be undertaken, while a process evaluation will monitor implementation of the interventions within the different regions with varying organisational and healthcare contexts. Discussion This multi-centre research seeks to overcome major

  16. Proxy decision making and dementia: Using Construal Level Theory to analyse the thoughts of decision makers.

    Science.gov (United States)

    Convey, Helen; Holt, Janet; Summers, Barbara

    2018-03-08

    This study explored the feasibility of using Construal Level Theory to analyse proxy decision maker thinking about a hypothetical ethical dilemma, relating to a person who has dementia. Proxy decision makers make decisions on behalf of individuals who are living with dementia when dementia affects that individual's decision making ability. Ethical dilemmas arise because there is a need to balance the individual's past and contemporary values and views. Understanding of how proxy decision makers respond is incomplete. Construal Level Theory contends that individuals imagine reactions and make predications about the future by crossing psychological distance. This involves abstract thinking, giving meaning to decisions. There is no empirical evidence of Construal Level Theory being used to analyse proxy decision maker thinking. Exploring the feasibility of using Construal Level Theory to understand dementia carer thinking regarding proxy decisions may provide insights which inform the support given. Descriptive qualitative research with semi-structured interviews. Seven participants were interviewed using a hypothetical dementia care scenario in February 2016. Interview transcripts were analysed for themes. Construal Level Theory was applied to analyse participant responses within themes using the Linguistic Category Model. Participants travelled across psychological distance, using abstract thinking to clarify goals and provide a basis for decisions. When thinking concretely participants established boundaries regarding the ethical dilemma. Construal Level Theory gives insight into proxy decision maker thinking and the levels of abstraction used. Understanding what dementia carers think about when making proxy decisions may help nurses to understand their perspectives and to provide appropriate support. © 2018 John Wiley & Sons Ltd.

  17. Using Pteropod Shells to Trace Aragonite Dissolution: Toward a Multi-Basin Calibration

    Science.gov (United States)

    Mekik, F. A.

    2013-12-01

    We developed a new proxy for tracing aragonite dissolution in marine sediments. The core tops we used are from the tropical and subtropical latitudes of two ocean basins: Atlantic and Pacific. This allows for a multi-basin calibration for our proxy which is based on the fragmentation trend of pteropod shells. The ratio of fragmented pteropod shells to whole plus fragmented pteropod shells within our core tops has an excellent relationship with the aragonite saturation of bottom waters. Combining our pteropod-based aragonite dissolution proxy with the Globorotalia menradii Fragmentation Index, which is a calcite dissolution proxy, allows tracing carbonate chemistry of bottom waters for the entire ocean depth profile including regions well above the calcite saturation horizon. We also present new data on size normalized weights of pteropod shells which supports the aragonite dissolution trend seen in the pteropod fragmentation data. Unlike previous findings with other proxies, both aragonite and calcite dissolution data from a high resolution core in the western equatorial Pacific reveal no evidence of a degacial carbonate preservation maximum.

  18. Multi-criteria clinical decision support: A primer on the use of multiple criteria decision making methods to promote evidence-based, patient-centered healthcare.

    Science.gov (United States)

    Dolan, James G

    2010-01-01

    Current models of healthcare quality recommend that patient management decisions be evidence-based and patient-centered. Evidence-based decisions require a thorough understanding of current information regarding the natural history of disease and the anticipated outcomes of different management options. Patient-centered decisions incorporate patient preferences, values, and unique personal circumstances into the decision making process and actively involve both patients along with health care providers as much as possible. Fundamentally, therefore, evidence-based, patient-centered decisions are multi-dimensional and typically involve multiple decision makers.Advances in the decision sciences have led to the development of a number of multiple criteria decision making methods. These multi-criteria methods are designed to help people make better choices when faced with complex decisions involving several dimensions. They are especially helpful when there is a need to combine "hard data" with subjective preferences, to make trade-offs between desired outcomes, and to involve multiple decision makers. Evidence-based, patient-centered clinical decision making has all of these characteristics. This close match suggests that clinical decision support systems based on multi-criteria decision making techniques have the potential to enable patients and providers to carry out the tasks required to implement evidence-based, patient-centered care effectively and efficiently in clinical settings.The goal of this paper is to give readers a general introduction to the range of multi-criteria methods available and show how they could be used to support clinical decision-making. Methods discussed include the balance sheet, the even swap method, ordinal ranking methods, direct weighting methods, multi-attribute decision analysis, and the analytic hierarchy process (AHP).

  19. Fanconi anemia group A and C double-mutant mice: functional evidence for a multi-protein Fanconi anemia complex.

    Science.gov (United States)

    Noll, Meenakshi; Battaile, Kevin P; Bateman, Raynard; Lax, Timothy P; Rathbun, Keany; Reifsteck, Carol; Bagby, Grover; Finegold, Milton; Olson, Susan; Grompe, Markus

    2002-07-01

    Fanconi anemia (FA) is a genetically heterogeneous disorder associated with defects in at least eight genes. The biochemical function(s) of the FA proteins are unknown, but together they define the FA pathway, which is involved in cellular responses to DNA damage and in other cellular processes. It is currently unknown whether all FA proteins are involved in controlling a single function or whether some of the FA proteins have additional roles. The aim of this study was 1) to determine whether the FA group A and group C genes have identical or partially distinct functions, and 2) to have a better model for human FA. We generated mice with a targeted mutation in fanca and crossed them with fancc disrupted animals. Several phenotypes including sensitivity to DNA cross linkers and ionizing radiation, hematopoietic colony growth, and germ cell loss were analyzed in fanca-/-, fancc-/-, fanca/fancc double -/-, and controls. Fibroblast cells and hematopoietic precursors from fanca/fancc double-mutant mice were not more sensitive to MMC than those of either single mutant. fanca/fancc double mutants had no evidence for an additive phenotype at the cellular or organismal level. These results support a model where both FANCA and FANCC are part of a multi-protein nuclear FA complex with identical function in cellular responses to DNA damage and germ cell survival.

  20. Multiscale combination of climate model simulations and proxy records over the last millennium

    Science.gov (United States)

    Chen, Xin; Xing, Pei; Luo, Yong; Nie, Suping; Zhao, Zongci; Huang, Jianbin; Tian, Qinhua

    2018-05-01

    To highlight the compatibility of climate model simulation and proxy reconstruction at different timescales, a timescale separation merging method combining proxy records and climate model simulations is presented. Annual mean surface temperature anomalies for the last millennium (851-2005 AD) at various scales over the land of the Northern Hemisphere were reconstructed with 2° × 2° spatial resolution, using an optimal interpolation (OI) algorithm. All target series were decomposed using an ensemble empirical mode decomposition method followed by power spectral analysis. Four typical components were obtained at inter-annual, decadal, multidecadal, and centennial timescales. A total of 323 temperature-sensitive proxy chronologies were incorporated after screening for each component. By scaling the proxy components using variance matching and applying a localized OI algorithm to all four components point by point, we obtained merged surface temperatures. Independent validation indicates that the most significant improvement was for components at the inter-annual scale, but this became less evident with increasing timescales. In mid-latitude land areas, 10-30% of grids were significantly corrected at the inter-annual scale. By assimilating the proxy records, the merged results reduced the gap in response to volcanic forcing between a pure reconstruction and simulation. Difficulty remained in verifying the centennial information and quantifying corresponding uncertainties, so additional effort should be devoted to this aspect in future research.

  1. Exploring multi-level system factors facilitating educator training and implementation of evidence-based practices (EBP): a study protocol.

    Science.gov (United States)

    Stahmer, Aubyn C; Suhrheinrich, Jessica; Schetter, Patricia L; McGee Hassrick, Elizabeth

    2018-01-08

    This study examines how system-wide (i.e., region, district, and school) mechanisms such as leadership support, training requirements, structure, collaboration, and education affect the use of evidence-based practices (EBPs) in schools and how this affects the outcomes for students with autism spectrum disorder (ASD). Despite growing evidence for the positive effects of EBPs for ASD, these practices are not consistently or effectively used in schools. Although special education programs are mandated to use EBPs, there are very few evidence-based methods for selecting, implementing, and sustaining EBPs. Research focuses primarily on teacher training, without attention to contextual factors (e.g., implementation climate, attitudes toward EBPs, resource allocation, and social networks) that may impact outcomes. Using an implementation science framework, this project will prospectively examine relations between system-wide factors and teachers' use of EBPs and student education outcomes. Survey data will be collected from approximately 85 regional special education directors, 170 regional program specialists, 265 district special education directors, 265 behavior specialists, 925 school principals, 3538 special education teachers, and 2700 paraprofessionals. Administrative data for the students with ASD served by participating teachers will be examined. A total of 79 regional-, district-, and school-level personnel will also participate in social network interviews. Mixed methods, including surveys, administrative data, and observational checklists, will be used to gather in-depth information about system-wide malleable factors that relate to positive teacher implementation of EBPs and student outcomes. Multi-level modeling will be used to assess system-wide malleable factors related to EBP implementation which will be linked to the trainer, teacher, and student outcomes and examined based on moderators (e.g., district size, Special Education Local Plan Area structure

  2. 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.

  3. The role of proxy information in missing data analysis.

    Science.gov (United States)

    Huang, Rong; Liang, Yuanyuan; Carrière, K C

    2005-10-01

    This article investigates the role of proxy data in dealing with the common problem of missing data in clinical trials using repeated measures designs. In an effort to avoid the missing data situation, some proxy information can be gathered. The question is how to treat proxy information, that is, is it always better to utilize proxy information when there are missing data? A model for repeated measures data with missing values is considered and a strategy for utilizing proxy information is developed. Then, simulations are used to compare the power of a test using proxy to simply utilizing all available data. It is concluded that using proxy information can be a useful alternative when such information is available. The implications for various clinical designs are also considered and a data collection strategy for efficiently estimating parameters is suggested.

  4. Evidence for a current sheet forming in the wake of a coronal mass ejection from multi-viewpoint coronagraph observations

    Science.gov (United States)

    Patsourakos, S.; Vourlidas, A.

    2011-01-01

    sheets. Therefore, our multi-viewpoint observations supply strong evidence that the observed post-CME ray is indeed related to a post-CME current sheet. Movies are only available in electronic form at http://www.aanda.org

  5. New evidence for a multi-functional role of herbivore-induced plant volatiles in defense against herbivores.

    Science.gov (United States)

    Rodriguez-Saona, Cesar R; Frost, Christopher J

    2010-01-01

    A diverse, often species-specific, array of herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack. Although research in the last 3 decades indicates a multi-functional role of these HIPVs, the evolutionary rationale underpinning HIPV emissions remains an open question. Many studies have documented that HIPVs can attract natural enemies, and some studies indicate that neighboring plants may eavesdrop their undamaged neighbors and induce or prime their own defenses prior to herbivore attack. Both of these ecological roles for HIPVs are risky strategies for the emitting plant. In a recent paper, we reported that most branches within a blueberry bush share limited vascular connectivity, which restricts the systemic movement of internal signals. Blueberry branches circumvent this limitation by responding to HIPVs emitted from neighboring branches of the same plant: exposure to HIPVs increases levels of defensive signaling hormones, changes their defensive status, and makes undamaged branches more resistant to herbivores. Similar findings have been reported recently for sagebrush, poplar and lima beans, where intra-plant communication played a role in activating or priming defenses against herbivores. Thus, there is increasing evidence that intra-plant communication occurs in a wide range of taxonomically unrelated plant species. While the degree to which this phenomenon increases a plant's fitness remains to be determined in most cases, we here argue that within-plant signaling provides more adaptive benefit for HIPV emissions than does between-plant signaling or attraction of predators. That is, the emission of HIPVs might have evolved primarily to protect undamaged parts of the plant against potential enemies, and neighboring plants and predators of herbivores later co-opted such HIPV signals for their own benefit.

  6. Validity of proxies and correction for proxy use when evaluating social determinants of health in stroke patients.

    Science.gov (United States)

    Skolarus, Lesli E; Sánchez, Brisa N; Morgenstern, Lewis B; Garcia, Nelda M; Smith, Melinda A; Brown, Devin L; Lisabeth, Lynda D

    2010-03-01

    The purpose of this study was to evaluate stroke patient-proxy agreement with respect to social determinants of health, including depression, optimism, and spirituality, and to explore approaches to minimize proxy-introduced bias. Stroke patient-proxy pairs from the Brain Attack Surveillance in Corpus Christi Project were interviewed (n=34). Evaluation of agreement between patient-proxy pairs included calculation of intraclass correlation coefficients, linear regression models (ProxyResponse=alpha(0)+alpha(1)PatientResponse+delta, where alpha(0)=0 and alpha(1)=1 denotes no bias) and kappa statistics. Bias introduced by proxies was quantified with simulation studies. In the simulated data, we applied 4 approaches to estimate regression coefficients of stroke outcome social determinants of health associations when only proxy data were available for some patients: (1) substituting proxy responses in place of patient responses; (2) including an indicator variable for proxy use; (3) using regression calibration with external validation; and (4) internal validation. Agreement was fair for depression (intraclass correlation coefficient, 0.41) and optimism (intraclass correlation coefficient, 0.48) and moderate for spirituality (kappa, 0.48 to 0.53). Responses of proxies were a biased measure of the patients' responses for depression, with alpha(0)=4.88 (CI, 2.24 to 7.52) and alpha(1)=0.39 (CI, 0.09 to 0.69), and for optimism, with alpha(0)=3.82 (CI, -1.04 to 8.69) and alpha(1)=0.81 (CI, 0.41 to 1.22). Regression calibration with internal validation was the most accurate method to correct for proxy-induced bias. Fair/moderate patient-proxy agreement was observed for social determinants of health. Stroke researchers who plan to study social determinants of health may consider performing validation studies so corrections for proxy use can be made.

  7. Optimizing TCP Performance over UMTS with Split TCP Proxy

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    . To cope with large delay bandwidth product, we propose a novel concept of split TCP proxy which is placed at GGSN between UNITS network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products which can...... be pipelined and thus operating at higher speeds. Simulation results show, the split TCP proxy can significantly improve the TCP performance in terms of RLC throughput under high bit rate DCH channel scenario (e.g.256 kbps). On the other hand, it only brings small performance improvement under low bit rate DCH...... 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...

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

    OpenAIRE

    Mtonga, Kambombo; Paul, Anand; Rho, Seungmin

    2014-01-01

    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 wi...

  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.

    Science.gov (United States)

    Irwin, Debra E; Gross, Heather E; Stucky, Brian D; Thissen, David; DeWitt, Esi Morgan; Lai, Jin Shei; Amtmann, Dagmar; Khastou, Leyla; Varni, James W; DeWalt, Darren A

    2012-02-22

    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. 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. 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 asthma, which was diagnosed or treated within 6

  11. 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

  12. Solar radio proxies for improved satellite orbit prediction

    Science.gov (United States)

    Yaya, Philippe; Hecker, Louis; Dudok de Wit, Thierry; Fèvre, Clémence Le; Bruinsma, Sean

    2017-12-01

    Specification and forecasting of solar drivers to thermosphere density models is critical for satellite orbit prediction and debris avoidance. Satellite operators routinely forecast orbits up to 30 days into the future. This requires forecasts of the drivers to these orbit prediction models such as the solar Extreme-UV (EUV) flux and geomagnetic activity. Most density models use the 10.7 cm radio flux (F10.7 index) as a proxy for solar EUV. However, daily measurements at other centimetric wavelengths have also been performed by the Nobeyama Radio Observatory (Japan) since the 1950's, thereby offering prospects for improving orbit modeling. Here we present a pre-operational service at the Collecte Localisation Satellites company that collects these different observations in one single homogeneous dataset and provides a 30 days forecast on a daily basis. Interpolation and preprocessing algorithms were developed to fill in missing data and remove anomalous values. We compared various empirical time series prediction techniques and selected a multi-wavelength non-recursive analogue neural network. The prediction of the 30 cm flux, and to a lesser extent that of the 10.7 cm flux, performs better than NOAA's present prediction of the 10.7 cm flux, especially during periods of high solar activity. In addition, we find that the DTM-2013 density model (Drag Temperature Model) performs better with (past and predicted) values of the 30 cm radio flux than with the 10.7 flux.

  13. 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

    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...... 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......, rather, have oriented it in certain ways. It is shown how the participating researchers – both senior and junior - have distinctive, incorporated dispositions with which they pre-consciously participate in an implicit and subtle relation that can make it very easy to overlook distortions during...

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

    OpenAIRE

    Gumanti, Tatang Ary

    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...

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

    African Journals Online (AJOL)

    in international markets. The proxy is a coincidental and pro-cyclic indicator, with a correlation of 0.86. Key similarities exist between the economy and the profitability of hardware stores, although the proxy is not as accurate as the volume of sales in hardware stores. The correlation is measured at 0.85. The profitability of the ...

  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. Belford proactive flood solutions: scientific evidence to influence local and national policy by multi-purpose runoff management

    Science.gov (United States)

    Wilkinson, M.; Quinn, P. F.; Jonczyk, J.

    2010-12-01

    The increased risk from flooding continues to be of concern to governments all around the world and flood protection is becoming more of a challenge. In the UK, climate change projections indicate more extremes within the weather systems. In addition, there is an increased demand for using land in urban areas beside channels. These developments both put pressure on our flood defences and there is a need for new solutions to managing flood risk. There is currently support within the England and Wales Environment Agency for sustainable flood management solutions such as storage ponds, wetlands, beaver dams and willow riparian features (referred to here as Runoff Attenuation Features, or RAFs). However the effectiveness of RAFs are not known at the catchment scale since they have only really been trailed at the plot scale. These types of mitigation measure can offer benefits to water quality and create ecological habitats. The village of Belford, situated in the Belford Burn catchment (6km2), northern England, has suffered from numerous flood events. In addition, the catchment suffers from water quality issues within the channel and high sediment loads are having an impact on the ecology of the nearby estuary. There was a desire by the Local Environment Agency Flood Levy team to deliver an alternative catchment-based solution to the problem. With funding from the Northumbria Regional Flood Defence Committee, the Environment Agency North East Local Levy team and Newcastle University have created a partnership to address the flood problem trailing soft engineered RAF’s at the catchment scale. The partnership project, “Belford proactive flood solutions” is testing novel techniques in reducing flood risk in small sub-catchments for the Environment Agency. The project provides the information needed to understand whether the multi-functional mitigation measures are working at the sub-catchment scale. Data suggest that the mitigation measures present have delayed the

  18. 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.

  19. Stereotypic and complex phrase types provide structural evidence for a multi-message display in humpback whales (Megaptera novaeangliae).

    Science.gov (United States)

    Murray, Anita; Dunlop, Rebecca A; Noad, Michael J; Goldizen, Anne W

    2018-02-01

    Male humpback whales produce a mating display called "song." Behavioral studies indicate song has inter- and/or intra-sexual functionality, suggesting song may be a multi-message display. Multi-message displays often include stereotypic components that convey group membership for mate attraction and/or male-male interactions, and complex components that convey individual quality for courtship. Humpback whale song contains sounds ("units") arranged into sequences ("phrases"). Repetitions of a specific phrase create a "theme." Within a theme, imperfect phrase repetitions ("phrase variants") create variability among phrases of the same type ("phrase type"). The hypothesis that song contains stereotypic and complex phrase types, structural characteristics consistent with a multi-message display, is investigated using recordings of 17 east Australian males (8:2004, 9:2011). Phrase types are categorized as stereotypic or complex using number of unit types, number of phrase variants, and the proportion of phrases that is unique to an individual versus shared amongst males. Unit types are determined using self-organizing maps. Phrase variants are determined by Levenshtein distances between phrases. Stereotypic phrase types have smaller numbers of unit types and shared phrase variants. Complex phrase types have larger numbers of unit types and unique phrase variants. This study supports the hypothesis that song could be a multi-message display.

  20. A multi-institutional study of the perceived barriers and facilitators to implementing evidence-based practice.

    Science.gov (United States)

    Duncombe, Daphne C

    2018-03-01

    To examine perceived barriers and facilitators to implementing evidence-based practice among nurses working in psychiatric, geriatric, hospital and community settings in The Bahamas. It is evident from previous studies that a number of factors exist which either obstruct or promote the utilisation of research evidence in nursing practice. Identifying these factors is vital to the successful uptake of evidence-based practice in nursing. Descriptive, comparative study. Data were collected using self-administered questionnaires. A stratified random sample (n = 100) of registered nurses participated; 5-point Likert-like scales were used to examine nurses' perceptions of barriers and facilitators of evidence-based practice. Descriptive statistics were used to describe demographic characteristics and to compare responses of nurses. Participants were predominantly female (98.4%), in the 25 to implement evidence-based practice previously. The greatest barriers identified were as follows: "Inadequate resources for implementing research findings" (85.2%; n = 52) and "Inadequate training in research methods" (83.6%; n = 51). The top facilitators identified were as follows: "Training in research methods" (88.5%; n = 54) and "Organisational policies and protocols that are evidence-based" (86.9%; n = 53). Nurses generally expressed that they required additional training in research and evidence-based practice concepts. Although some nurses had a desire to implement evidence-based practice to provide quality care and improve patient outcomes, many expressed that they lacked the required resources. The study draws attention to the need for prioritisation of evidence-based practice both at institutional and governmental levels. Successful adoption of evidence-based practice implies combined efforts of nurses, healthcare providers and policymakers. Further research is needed to determine the best method for successfully incorporating evidence-based practice into nursing

  1. Comparing Apples to Apples: Paleoclimate Model-Data comparison via Proxy System Modeling

    Science.gov (United States)

    Dee, Sylvia; Emile-Geay, Julien; Evans, Michael; Noone, David

    2014-05-01

    under assumed dating uncertainties. We demonstrate the utility of the PSM framework with an integrative multi-PSM simulation. An intermediate-complexity AGCM with isotope physics (SPEEDY-IER, (Molteni, 2003, Dee et al., in prep)) is used to simulate the isotope hydrology and atmospheric response to SSTs derived from the LM PMIP3 integration of the CCSM4 model (Landrum et al., 2012). Relevant dynamical and isotope variables are then used to drive PSMs, emulating a realistic multiproxy network (Emile-Geay et al., 2013). We then ask the following question: given our best knowledge of proxy systems, what aspects of GCM behavior may be validated, and with what uncertainties? We approach this question via a three-tiered 'perfect model' study. A random realization of the simulated proxy data (hereafter 'PaleoObs') is used as a benchmark in the following comparisons: (1) AGCM output (without isotopes) vs. PaleoObs; (2) AGCM output (with isotopes) vs. PaleoObs; (3) coupled AGCM-PSM-simulated proxy ensemble vs. PaleoObs. Enhancing model-data comparison using PSMs highlights uncertainties that may arise from ignoring non-linearities in proxy-climate relationships, or the presence of age uncertainties (as is most typically done is paleoclimate model-data intercomparison). Companion experiments leveraging the 3 sub-model compartmentalization of PSMs allows us to quantify the contribution of each sub-system to the observed model-data discrepancies. We discuss potential repercussions for model-data comparison and implications for validating predictive climate models using paleodata. References Braconnot, P., Harrison, S. P., Kageyama, M., Bartlein, P. J., Masson-Delmotte, V., Abe-Ouchi, A., Otto-Bliesner, B., Zhao, Y., 06 2012. Evaluation of climate models using palaeoclimatic data. Nature Clim. Change 2 (6), 417-424. URL http://dx.doi.org/10.1038/nclimate1456 Emile-Geay, J., Cobb, K. M., Mann, M. E., Wittenberg, A. T., Apr 01 2013. Estimating central equatorial pacific sst

  2. 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.

  3. 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.

  4. The Characteristics of Multi-Unit Ownership in Franchising: Evidence from Fast-Food Restaurants in Texas

    OpenAIRE

    Arturs Kalnins; Francine Lafontaine

    1996-01-01

    One empirical phenomenon that has received little attention in the franchising literature is the tendency for individual franchisees to own not just one but several units of a given franchised chain. Most current theories of franchising, based on incentives, information asymmetries, and strategic arguments, have little capacity to explain this phenomenon. In fact, several of them imply that all units should be independently owned and operated. However, given the existence of multi-unit owners...

  5. Multi-asset class mutual funds: Can they time the market? Evidence from the US, UK and Canada

    OpenAIRE

    Clare, A.; O'Sullivan, N.; Sherman, M.; Thomas, S.

    2016-01-01

    The importance of asset allocation decisions in wealth management is well established. However, given its importance it is perhaps surprising that so little attention has been paid to the question of whether professional fund managers are skilful at timing market movement across asset classes over time. The timing literature has tended to concentrate on the timing skill of single asset class funds. Using data on US, UK and Canadian multi-asset class funds, we apply two alternative methodologi...

  6. 'Marginal Employment' and the Demand for Heterogenous Labour: Empirical Evidence from a Multi-factor Labour Demand Model for Germany

    OpenAIRE

    Ronny Freier; Viktor Steiner

    2007-01-01

    We develop a structural multi-factor labour demand model which distinguishes between eight labour categories including non-standard types of employment such as marginal employment. The model is estimated for both the number of workers and total working hours using a new panel data set. For unskilled and skilled workers in full-time employment, we find labour demand elasticities similar to previous estimates for the west German economy. Our new estimates of own-wage elasticities for marginal e...

  7. Tree-Based Ecosystem Approaches (TBEAs as Multi-Functional Land Management Strategies—Evidence from Rwanda

    Directory of Open Access Journals (Sweden)

    Miyuki Iiyama

    2018-04-01

    Full Text Available Densely populated rural areas in the East African Highlands have faced significant intensification challenges under extreme population pressure on their land and ecosystems. Sustainable agricultural intensification, in the context of increasing cropping intensities, is a prerequisite for deliberate land management strategies that deliver multiple ecosystem goods (food, energy, income sources, etc. and services (especially improving soil conditions on the same land, as well as system resilience, if adopted at scale. Tree based ecosystem approaches (TBEAs are among such multi-functional land management strategies. Knowledge on the multi-functionality of TBEAs and on their scaling up, however, remains severely limited due to several methodological challenges. This study aims at offering an analytical perspective to view multi-functional TBEAs as an integral part of sustainable agricultural intensification. The study proposes a conceptual framework to guide the analysis of socio-economic data and applies it to cross-site analysis of TBEAs in extremely densely populated Rwanda. Heterogeneous TBEAs were identified across Rwanda’s different agro-ecological zones to meet locally-specific smallholders’ needs for a set of ecosystem goods and services on the same land. The sustained adoption of TBEAs would be guaranteed if farmers subjectively recognize their compatibility and synergy with sustainable intensification of existing farming systems, supported by favorable institutional conditions.

  8. 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.

  9. 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

  10. Solar radio proxies for improved satellite orbit prediction

    Directory of Open Access Journals (Sweden)

    Yaya Philippe

    2017-01-01

    Full Text Available Specification and forecasting of solar drivers to thermosphere density models is critical for satellite orbit prediction and debris avoidance. Satellite operators routinely forecast orbits up to 30 days into the future. This requires forecasts of the drivers to these orbit prediction models such as the solar Extreme-UV (EUV flux and geomagnetic activity. Most density models use the 10.7 cm radio flux (F10.7 index as a proxy for solar EUV. However, daily measurements at other centimetric wavelengths have also been performed by the Nobeyama Radio Observatory (Japan since the 1950's, thereby offering prospects for improving orbit modeling. Here we present a pre-operational service at the Collecte Localisation Satellites company that collects these different observations in one single homogeneous dataset and provides a 30 days forecast on a daily basis. Interpolation and preprocessing algorithms were developed to fill in missing data and remove anomalous values. We compared various empirical time series prediction techniques and selected a multi-wavelength non-recursive analogue neural network. The prediction of the 30 cm flux, and to a lesser extent that of the 10.7 cm flux, performs better than NOAA's present prediction of the 10.7 cm flux, especially during periods of high solar activity. In addition, we find that the DTM-2013 density model (Drag Temperature Model performs better with (past and predicted values of the 30 cm radio flux than with the 10.7 flux.

  11. Planktonic Foraminifera Proxies Calibration Off the NW Iberian Margin: Nutrients Approach

    Science.gov (United States)

    Salgueiro, E.; Castro, C. G.; Zuniga, D.; Martin, P. A.; Groeneveld, J.; de la Granda, F.; Villaceiros-Robineau, N.; Alonso-Perez, F.; Alberto, A.; Rodrigues, T.; Rufino, M. M.; Abrantes, F. F. G.; Voelker, A. H. L.

    2014-12-01

    Planktonic foraminifera (PF) shells preserved in marine sediments are a useful tool to reconstruct productivity conditions at different geological timescales. However, the accuracy of these paleoreconstructions depends on the data set and calibration quality. Several calibration works have been defining and improving the use of proxies for productivity and nutrient cycling parameters. Our contribution is centred on a multi-proxy calibration at a regional coastal upwelling system. To minimize the existing uncertainties affecting the use of trace elements and C stable isotopes as productivity proxy in the high productivity upwelling areas, we investigate the content and distribution of Ba/Ca and δ13C in the water column, its transference into the planktonic foraminifera shells, and, how the living planktonic foraminifera Ba/Ca and δ13C signal is related to the same planktonic foraminiferal species preserved in the sediment record. This study is based on a large data set from two stations (RAIA - 75m water depth, and CALIBERIA - 350m water depth) located off the NW Iberian margin (41.5-42.5ºN; 9-10ºW), and includes: i) two year monthly water column data (temperature, salinity, nutrients, chlorophyll a, Ba/Ca, and δ13C-DIC); ii) seasonal Ba/Ca, δ13C in several living PF species at both stations; and iii) Ba/Ca and δ13C in several PF species from a large set of core-top sediment samples in the study region. Additionally, total organic carbon and total alkenones were also measured in the sediment. Our results showed the link between productivity proxies in the surface sediment foraminifera assemblage and the processes regulating the actual phytoplankton dynamics in an upwelling area. The understanding of this relationship has special relevance since it gives fundamental information related to the past oceanic biogeochemistry and/or climate and improves the prevision of future changes against possible climate variability due to anthropogenic forcing.

  12. A Single Session of rTMS Enhances Small-Worldness in Writer’s Cramp: Evidence from Simultaneous EEG-fMRI Multi-Modal Brain Graph

    Directory of Open Access Journals (Sweden)

    Rose D. Bharath

    2017-09-01

    Full Text Available Background and Purpose: Repetitive transcranial magnetic stimulation (rTMS induces widespread changes in brain connectivity. As the network topology differences induced by a single session of rTMS are less known we undertook this study to ascertain whether the network alterations had a small-world morphology using multi-modal graph theory analysis of simultaneous EEG-fMRI.Method: Simultaneous EEG-fMRI was acquired in duplicate before (R1 and after (R2 a single session of rTMS in 14 patients with Writer’s Cramp (WC. Whole brain neuronal and hemodynamic network connectivity were explored using the graph theory measures and clustering coefficient, path length and small-world index were calculated for EEG and resting state fMRI (rsfMRI. Multi-modal graph theory analysis was used to evaluate the correlation of EEG and fMRI clustering coefficients.Result: A single session of rTMS was found to increase the clustering coefficient and small-worldness significantly in both EEG and fMRI (p < 0.05. Multi-modal graph theory analysis revealed significant modulations in the fronto-parietal regions immediately after rTMS. The rsfMRI revealed additional modulations in several deep brain regions including cerebellum, insula and medial frontal lobe.Conclusion: Multi-modal graph theory analysis of simultaneous EEG-fMRI can supplement motor physiology methods in understanding the neurobiology of rTMS in vivo. Coinciding evidence from EEG and rsfMRI reports small-world morphology for the acute phase network hyper-connectivity indicating changes ensuing low-frequency rTMS is probably not “noise”.

  13. A Multi-level Examination of how the Organizational Context Relates to Readiness to Implement Prevention and Evidence-Based Programming in Community Settings

    Science.gov (United States)

    Chilenski, Sarah M.; Olson, Jonathan R.; Schulte, Jill A.; Perkins, Daniel F.; Spoth, Richard

    2015-01-01

    Prior theoretical and empirical research suggests that multiple aspects of an organization’s context are likely related to a number of factors, from their interest and ability to adopt new programming, to client outcomes. A limited amount of the prior research has taken a more community-wide perspective by examining factors that associate with community readiness for change, leaving how these findings generalize to community organizations that conduct prevention or positive youth development programs unknown. Thus for the current study, we examined how the organizational context of the Cooperative Extension System (CES) associates with current attitudes and practices regarding prevention and evidence-based programming. Attitudes and practices have been found in the empirical literature to be key indicators of an organization’s readiness to adopt prevention and evidence-based programming. Based on multi-level mixed models, results indicate that organizational management practices distinct from program delivery may affect an organization’s readiness to adopt and implement new prevention and evidence-based youth programs, thereby limiting the potential public health impact of evidence-based programs. Openness to change, openness of leadership, and communication were the strongest predictors identified within this study. An organization’s morale was also found to be a strong predictor of an organization’s readiness. The findings of the current study are discussed in terms of implications for prevention and intervention. PMID:25463014

  14. Experimental evidence of the generation of multi-hundred megabar pressures in 0. 26. mu. m wavelength laser experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fabro, R.; Faral, B.; Virmont, J.; Pepin, H.; Cottet, F.; Romain, J.P.

    A 9 ..mu..m thick aluminium foil is accelerated to a velocity of about 160 km/s by a laser of 0.26 ..mu..m wavelength and intensity of 10/sup 15/ W/cm/sup 2/ and collides with an aluminium impact foil. The measurement of the velocity of the induced shock wave in the impact foil, using a step method at the rear of the impact foil, gives pressures in the multi-hundred megabar range. The dynamics and constraints of this shock wave are presented and the effect of X-ray preheating, which can be important at this laser wavelength, is discussed.

  15. 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)

  16. Ocean currents generate large footprints in marine palaeoclimate proxies

    NARCIS (Netherlands)

    van Sebille, E.; Scussolini, P.; Durgadoo, J.V.; Peeters, F.J.C.; Biastoch, A.; Weijer, W.; Turney, C.; Paris, C.B.; Zahn, R.

    2015-01-01

    Fossils of marine microorganisms such as planktic foraminifera are among the cornerstones of palaeoclimatological studies. It is often assumed that the proxies derived from their shells represent ocean conditions above the location where they were deposited. Planktic foraminifera, however, are

  17. 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....

  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. The Difference Between Using Proxy Server and VPN

    Directory of Open Access Journals (Sweden)

    David Dwiputra Kurniadi

    2015-11-01

    For example, looking for software, game through internet. But sometimes, there are some websites that cannot be opened as they have Internet Positive notificatio. To solve that problem, hacker found the solution by creating Proxy Server or VPN. In this time internet is very modern and very easy to access and there are a lot of Proxy Server and VPN that can be easly used.

  20. Unearthing earthquakes and their tsunamis using multiple proxies: the 22 June 1932 event and a probable fourteenth-century predecessor on the Pacific coast of Mexico

    Czech Academy of Sciences Publication Activity Database

    Ramírez-Herrera, M.-T.; Corona, N.; Lagos, M.; Černý, Jan; Goguitchaichvili, A.; Goff, J.; Chaugé-Goff, C.; Machain, M. L.; Zawadzki, A.; Jacobsen, G.; Carranza-Edwards, A.; Lozano, S.; Blecher, L.

    2014-01-01

    Roč. 56, č. 13 (2014), s. 1584-1601 ISSN 0020-6814 Institutional support: RVO:67985831 Keywords : tsunami deposits * palaeotsunami * tropical environment * multi-proxy approach * Pacific coast * México Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.708, year: 2014

  1. A multi-faceted approach to promote knowledge translation platforms in eastern Mediterranean countries: climate for evidence-informed policy

    Directory of Open Access Journals (Sweden)

    El-Jardali Fadi

    2012-05-01

    Full Text Available Abstract Objectives Limited work has been done to promote knowledge translation (KT in the Eastern Mediterranean Region (EMR. The objectives of this study are to: 1.assess the climate for evidence use in policy; 2.explore views and practices about current processes and weaknesses of health policymaking; 3.identify priorities including short-term requirements for policy briefs; and 4.identify country-specific requirements for establishing KT platforms. Methods Senior policymakers, stakeholders and researchers from Algeria, Bahrain, Egypt, Iran, Jordan, Lebanon, Oman, Sudan, Syria, Tunisia, and Yemen participated in this study. Questionnaires were used to assess the climate for use of evidence and identify windows of opportunity and requirements for policy briefs and for establishing KT platforms. Current processes and weaknesses of policymaking were appraised using case study scenarios. Closed-ended questions were analyzed descriptively. Qualitative data was analyzed using thematic analysis. Results KT activities were not frequently undertaken by policymakers and researchers in EMR countries, research evidence about high priority policy issues was rarely made available, and interaction between policymakers and researchers was limited, and policymakers rarely identified or created places for utilizing research evidence in decision-making processes. Findings emphasized the complexity of policymaking. Donors, political regimes, economic goals and outdated laws were identified as key drivers. Lack of policymakers’ abilities to think strategically, constant need to make quick decisions, limited financial resources, and lack of competent and trained human resources were suggested as main weaknesses. Conclusion Despite the complexity of policymaking processes in countries from this region, the absence of a structured process for decision making, and the limited engagement of policymakers and researchers in KT activities, there are windows of

  2. A multi-faceted approach to promote knowledge translation platforms in eastern Mediterranean countries: climate for evidence-informed policy.

    Science.gov (United States)

    El-Jardali, Fadi; Ataya, Nour; Jamal, Diana; Jaafar, Maha

    2012-05-06

    Limited work has been done to promote knowledge translation (KT) in the Eastern Mediterranean Region (EMR). The objectives of this study are to: 1.assess the climate for evidence use in policy; 2.explore views and practices about current processes and weaknesses of health policymaking; 3.identify priorities including short-term requirements for policy briefs; and 4.identify country-specific requirements for establishing KT platforms. Senior policymakers, stakeholders and researchers from Algeria, Bahrain, Egypt, Iran, Jordan, Lebanon, Oman, Sudan, Syria, Tunisia, and Yemen participated in this study. Questionnaires were used to assess the climate for use of evidence and identify windows of opportunity and requirements for policy briefs and for establishing KT platforms. Current processes and weaknesses of policymaking were appraised using case study scenarios. Closed-ended questions were analyzed descriptively. Qualitative data was analyzed using thematic analysis. KT activities were not frequently undertaken by policymakers and researchers in EMR countries, research evidence about high priority policy issues was rarely made available, and interaction between policymakers and researchers was limited, and policymakers rarely identified or created places for utilizing research evidence in decision-making processes. Findings emphasized the complexity of policymaking. Donors, political regimes, economic goals and outdated laws were identified as key drivers. Lack of policymakers' abilities to think strategically, constant need to make quick decisions, limited financial resources, and lack of competent and trained human resources were suggested as main weaknesses. Despite the complexity of policymaking processes in countries from this region, the absence of a structured process for decision making, and the limited engagement of policymakers and researchers in KT activities, there are windows of opportunity for moving towards more evidence informed policymaking.

  3. Multi-interdisciplinary evidence of the Holocene history of a cultivated flood plain area in the wetlands of northern Colombia

    International Nuclear Information System (INIS)

    Berrio, Juan Carlos; Boom, Arnoud; Botero, Pedro; Herrera, Luisa Fernanda; Hooghiemstra, Henry; Romero, Freddy; Sarmiento Gustavo

    2002-01-01

    An environmental reconstruction of the last 10,000 14 C years of a frequently flooded wetland ecosystem in the lower Magdalena Valley in northern Colombia is presented on the basis of a multi-disciplinary study of the sediments of the upper 15 m the core from Boquillas (74 degrade 33' E, 9 degrade 7' N; 20 m a.s.l.). We used the following studies: pollen, lithology, organic structures, clay mineralogy, soil and sediment geochemistry, and 013C values. The chronology is based on 13 AMS 14 C dates; of 7 samples the humid acid fractions were used in the case of seven samples. Pollen from local origin (swamps, open grass-rich vegetation, and gallery forest) shows the development of the wetland area. River-transported pollen from greater distance (dry forest, montane forest, Alnus) shows changes in river activity and reflects large-scale changes of climatic conditions in the Momposina basin

  4. Evidence of neurofibromatosis type 1 in a multi-morbid Inca child mummy: A paleoradiological investigation using computed tomography.

    Science.gov (United States)

    Panzer, Stephanie; Wittig, Holger; Zesch, Stephanie; Rosendahl, Wilfried; Blache, Sandra; Müller-Gerbl, Magdalena; Hotz, Gerhard

    2017-01-01

    In this study, an Inca bundle was examined using computed tomography (CT). The primary aim was to determine the preservation status of bony and soft tissues, the sex, the age at the time of death, possible indicators for disease or even the cause of death, as well as the kind of mummification. A secondary aim was to obtain a brief overview of the wrapping in order to gain additional information on the cultural background. The bundle belongs to the Museum of Cultures in Basel, Switzerland, and was bought in Munich, Germany, in 1921. Radiocarbon dating of the superficial textile yielded a calibrated age between 1480 and 1650 AD. The mummy was investigated using multi-slice CT with slice thickness of 0.75 mm and 110 kilovolt. For standardized assessment of soft tissue preservation, a recently developed checklist was applied. CT revealed the mummy of a seven to nine year old boy with superior preservation of bony and soft tissues allowing detailed assessment. Indicators of neurofibromatosis type 1 (paravertebral and cutaneous neurofibromas, a breast neurofibroma, sphenoid wing dysplasia), Chagas disease (dilatation of the esophagus, stomach, rectum, and large amounts of feces), and lung infection (pleural adherence, calcifications), probably due to tuberculosis, were found. Furthermore, signs of peri-mortem violence (transection of the chest and a defect in the abdominal wall) were detected. CT images revealed a carefully performed wrapping. CT examination of the Inca bundle proved to be an important non-destructive examination method. Standardized assessment, especially of the soft tissue structures, allowed for diagnoses of several diseases, indicating a multi-morbid child at the time of death. The careful wrapping pointed to a ceremonial burial. Within the cultural background, the signs of fatal violence were discussed as a possible result of war, murder, accident, or human sacrifice.

  5. Evidence of neurofibromatosis type 1 in a multi-morbid Inca child mummy: A paleoradiological investigation using computed tomography.

    Directory of Open Access Journals (Sweden)

    Stephanie Panzer

    Full Text Available In this study, an Inca bundle was examined using computed tomography (CT. The primary aim was to determine the preservation status of bony and soft tissues, the sex, the age at the time of death, possible indicators for disease or even the cause of death, as well as the kind of mummification. A secondary aim was to obtain a brief overview of the wrapping in order to gain additional information on the cultural background.The bundle belongs to the Museum of Cultures in Basel, Switzerland, and was bought in Munich, Germany, in 1921. Radiocarbon dating of the superficial textile yielded a calibrated age between 1480 and 1650 AD. The mummy was investigated using multi-slice CT with slice thickness of 0.75 mm and 110 kilovolt. For standardized assessment of soft tissue preservation, a recently developed checklist was applied.CT revealed the mummy of a seven to nine year old boy with superior preservation of bony and soft tissues allowing detailed assessment. Indicators of neurofibromatosis type 1 (paravertebral and cutaneous neurofibromas, a breast neurofibroma, sphenoid wing dysplasia, Chagas disease (dilatation of the esophagus, stomach, rectum, and large amounts of feces, and lung infection (pleural adherence, calcifications, probably due to tuberculosis, were found. Furthermore, signs of peri-mortem violence (transection of the chest and a defect in the abdominal wall were detected. CT images revealed a carefully performed wrapping.CT examination of the Inca bundle proved to be an important non-destructive examination method. Standardized assessment, especially of the soft tissue structures, allowed for diagnoses of several diseases, indicating a multi-morbid child at the time of death. The careful wrapping pointed to a ceremonial burial. Within the cultural background, the signs of fatal violence were discussed as a possible result of war, murder, accident, or human sacrifice.

  6. Family factors in end-of-life decision-making: family conflict and proxy relationship.

    Science.gov (United States)

    Parks, Susan Mockus; Winter, Laraine; Santana, Abbie J; Parker, Barbara; Diamond, James J; Rose, Molly; Myers, Ronald E

    2011-02-01

    Few studies have examined proxy decision-making regarding end-of-life treatment decisions. Proxy accuracy is defined as whether proxy treatment choices are consistent with the expressed wishes of their index elder. The purpose of this study was to examine proxy accuracy in relation to two family factors that may influence proxy accuracy: perceived family conflict and type of elder-proxy relationship. Telephone interviews with 202 community-dwelling elders and their proxy decision makers were conducted including the Life-Support Preferences Questionnaire (LSPQ), and a measure of family conflict, and sociodemographic characteristics, including type of relationship. Elder-proxy accuracy was associated with the type of elder-proxy relationship. Adult children demonstrated the lowest elder-proxy accuracy and spousal proxies the highest elder-proxy accuracy. Elder-proxy accuracy was associated with family conflict. Proxies reporting higher family conflict had lower elder-proxy accuracy. No interaction between family conflict and relationship type was revealed. Spousal proxies were more accurate in their substituted judgment than adult children, and proxies who perceive higher degree of family conflict tended to be less accurate than those with lower family conflict. Health care providers should be aware of these family factors when discussing advance care planning.

  7. Multi-agent gully processes: Evidence from the Monaro Volcanic Province, Australia and in Terra Cimmeria, Mars

    Science.gov (United States)

    Hobbs, S. W.; Paull, D. J.; Clarke, J. D. A.; Roach, Ian C.

    2016-03-01

    Comparison of the similarities and differences between terrestrial and Martian hillside gullies promotes understanding of how surface processes operate on both planets. Here we tested the viability of subsurface flow of water as a process affecting gully evolution. We compared gullies within the Monaro Volcanic Province near Cooma, New South Wales, Australia, to gullies possessing strong structural control near Gasa Crater, Terra Cimmeria, Mars. Although cursory examination of the Monaro gullies initially suggested strong evidence for aquifer erosion, detailed field surveys showed the evidence to be ambiguous. Instead a complex regime of erosion dependent on multiple conditions and processes such as local geology, surface runoff, dry mass wasting, and animal activity emerged. We found the morphology of gullies near Gasa Crater to be consistent with erosion caused by liquid water, while also being heavily influenced by the local environment, including slope and geology. Additionally, erosion at the Martian site was not consistent with evidence of subsequent, smaller scale erosion and channel modification by dry mass wasting. Local conditions thus play an important role in gully evolution, further highlighting that processes forming Martian gullies may be more diverse than initially thought.

  8. Multi-tyrosine kinase inhibitors in preclinical studies for pediatric CNS AT/RT: Evidence for synergy with Topoisomerase-I inhibition

    Directory of Open Access Journals (Sweden)

    Jayanthan Aarthi

    2011-12-01

    Full Text Available Abstract Background Currently, Atypical Teratoid Rhabdoid Tumor (AT/RT constitutes one of the most difficult to treat malignancies in pediatrics. Hence, new knowledge of potential targets for therapeutics and the development of novel treatment approaches are urgently needed. We have evaluated the presence of cytokine pathways and the effects of two clinically available multi-tyrosine kinase inhibitors for cytotoxicity, target modulation and drug combinability against AT/RT cell lines. Results AT/RT cell lines expressed measurable quantities of VEGF, FGF, PDGF and SDF-1, although the absolute amounts varied between the cell lines. The targeted receptor tyrosine kinase inhibitor sorafenib inhibited the key signaling molecule Erk, which was activated following the addition of own conditioned media, suggesting the existence of autocrine/paracrine growth stimulatory pathways. The multi-tyrosine kinase inhibitors sorafenib and sunitinib also showed significant growth inhibition of AT/RT cells and their activity was enhanced by combination with the topoisomerase inhibitor, irinotecan. The loss of cytoplasmic NF-kappa-B in response to irinotecan was diminished by sorafenib, providing evidence for a possible benefit for this drug combination. Conclusions In addition to previously described involvement of insulin like growth factor (IGF family of cytokines, a multitude of other growth factors may contribute to the growth and survival of AT/RT cells. However, consistent with the heterogeneous nature of this tumor, quantitative and qualitative differences may exist among different tumor samples. Multi-tyrosine kinase inhibitors appear to have effective antitumor activity against all cell lines studied. In addition, the target modulation studies and drug combinability data provide the groundwork for additional studies and support the evaluation of these agents in future treatment protocols.

  9. Climatic trends and anomalies in Europe 1675-1715. High resolution spatio-temporal reconstructions from direct meteorological observations and proxy data: Methods and results

    International Nuclear Information System (INIS)

    Frenzel, B.; Pfister, C.; Glaeser, B.

    1994-01-01

    This volume contains the proceedings of a conference held at the University of Bern in Switzerland on 2-4 September 1992 by a group of historical geographers, historians, palaeobotanists and meteorologists originating from fifteen European nations as well as from China and Japan. It was the first international symposium of this kind for which the participants had previously submitted various kinds of palaeoclimatic data - early instrumental series, documentary data, dendroclimatic data - in a standardized form to a common data base in order to have this evidence ready to include in a pan-European multi-proxy mapping scheme at the time of the meeting. A team of meteorological experts worked on interpreting some of these data in terms of rough monthly synoptic weather situations in order to test the suitability of the evidence for this purpose. This volume includes both the regional contributions of the individual partners presented at the Bern workshop, as well as the two hundred monthly synoptic weather maps which resulted from the common effort of the group of meteorologists at the Copenhagen meeting. (orig.)

  10. Reported Systems Changes and Sustainability Perceptions of Three State Departments of Health Implementing Multi-Faceted Evidence-Based Fall Prevention Efforts

    Directory of Open Access Journals (Sweden)

    Matthew Lee Smith

    2017-06-01

    Full Text Available Although the concepts of systems change and sustainability are not new, little is known about the factors associated with systems change sustaining multi-state, multi-level fall prevention efforts. This exploratory study focuses on three State Departments of Health (DOH that were awarded 5-year funding from the Centers for Disease Control and Prevention to simultaneously implement four separate yet related evidence-based fall prevention initiatives at the clinical, community, and policy level. The purpose of this study was to examine changes in partnerships and collaborative activities that occurred to accomplish project goals (examining changes in the context of “before funding” and “after funding was received”. Additionally, this study explored changes in State DOH perceptions about action related to sustainability indicators in the context of “during funding” and “after funding ends.” Findings from this study document the partnership and activity changes necessary to achieve defined fall prevention goals after funding is received, and that the importance of sustainability indicator documentation is seen as relevant during funding, but less so after the funding ends. Findings from this study have practice and research implications that can inform future funded efforts in terms of sector and stakeholder engagement necessary for initiating, implementing, and sustaining community- and clinical-based fall prevention interventions.

  11. Post-error response inhibition in high math-anxious individuals: Evidence from a multi-digit addition task.

    Science.gov (United States)

    Núñez-Peña, M Isabel; Tubau, Elisabet; Suárez-Pellicioni, Macarena

    2017-06-01

    The aim of the study was to investigate how high math-anxious (HMA) individuals react to errors in an arithmetic task. Twenty HMA and 19 low math-anxious (LMA) individuals were presented with a multi-digit addition verification task and were given response feedback. Post-error adjustment measures (response time and accuracy) were analyzed in order to study differences between groups when faced with errors in an arithmetical task. Results showed that both HMA and LMA individuals were slower to respond following an error than following a correct answer. However, post-error accuracy effects emerged only for the HMA group, showing that they were also less accurate after having committed an error than after giving the right answer. Importantly, these differences were observed only when individuals needed to repeat the same response given in the previous trial. These results suggest that, for HMA individuals, errors caused reactive inhibition of the erroneous response, facilitating performance if the next problem required the alternative response but hampering it if the response was the same. This stronger reaction to errors could be a factor contributing to the difficulties that HMA individuals experience in learning math and doing math tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. EVIDENCE FOR TWO LOGNORMAL STATES IN MULTI-WAVELENGTH FLUX VARIATION OF FSRQ PKS 1510-089

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Pankaj; Misra, Ranjeev [Inter University Center for Astronomy and Astrophysics, Pune 411007 (India); Chandra, Sunil; Singh, K. P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Sahayanathan, S. [Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Baliyan, K. S., E-mail: pankajk@iucaa.in [Physical Research Laboratory, Ahmedabad 380009 (India)

    2016-05-01

    We present a systematic characterization of multi-wavelength emission from blazar PKS 1510-089 using well-sampled data at near-infrared (NIR), optical, X-ray, and γ -ray energies. The resulting flux distributions, except at X-rays, show two distinct lognormal profiles corresponding to a high and a low flux level. The dispersions exhibit energy-dependent behavior except in the LAT γ -ray and optical B-band. During the low level flux states, it is higher toward the peak of the spectral energy distribution, with γ -ray being intrinsically more variable followed by IR and then optical, consistent with mainly being a result of varying bulk Lorentz factor. On the other hand, the dispersions during the high state are similar in all bands except the optical B-band, where thermal emission still dominates. The centers of distributions are a factor of ∼4 apart, consistent with anticipation from studies of extragalactic γ -ray background with the high state showing a relatively harder mean spectral index compared to the low state.

  13. The Multi-Frequency Correlation Between Eua and sCER Futures Prices: Evidence from the Emd Approach

    Science.gov (United States)

    Zhang, Yue-Jun; Huang, Yi-Song

    2015-05-01

    Currently European Union Allowances (EUA) and secondary Certified Emission Reduction (sCER) have become two dominant carbon trading assets for investors and their linkage attracts much attention from academia and practitioners in recent years. Under this circumstance, we use the empirical mode decomposition (EMD) approach to decompose the two carbon futures contract prices and discuss their correlation from the multi-frequency perspective. The empirical results indicate that, first, the EUA and sCER futures price movements can be divided into those triggered by the long-term, medium-term and short-term market impacts. Second, the price movements in the EUA and sCER futures markets are primarily caused by the long-term impact, while the short-term impact can only explain a small fraction. Finally, the long-term (short-term) effect on EUA prices is statistically uncorrelated with the short-term (long-term) effect of sCER prices, and there is a medium or strong lead-and-lag correlation between the EUA and sCER price components with the same time scales. These results may provide some important insights of price forecast and arbitraging activities for carbon futures market investors, analysts and regulators.

  14. Gradient-based model calibration with proxy-model assistance

    Science.gov (United States)

    Burrows, Wesley; Doherty, John

    2016-02-01

    Use of a proxy model in gradient-based calibration and uncertainty analysis of a complex groundwater model with large run times and problematic numerical behaviour is described. The methodology is general, and can be used with models of all types. The proxy model is based on a series of analytical functions that link all model outputs used in the calibration process to all parameters requiring estimation. In enforcing history-matching constraints during the calibration and post-calibration uncertainty analysis processes, the proxy model is run for the purposes of populating the Jacobian matrix, while the original model is run when testing parameter upgrades; the latter process is readily parallelized. Use of a proxy model in this fashion dramatically reduces the computational burden of complex model calibration and uncertainty analysis. At the same time, the effect of model numerical misbehaviour on calculation of local gradients is mitigated, this allowing access to the benefits of gradient-based analysis where lack of integrity in finite-difference derivatives calculation would otherwise have impeded such access. Construction of a proxy model, and its subsequent use in calibration of a complex model, and in analysing the uncertainties of predictions made by that model, is implemented in the PEST suite.

  15. 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.

  16. Vervet monkey (Chlorocebus pygerythrus) behavior in a multi-destination route: Evidence for planning ahead when heuristics fail.

    Science.gov (United States)

    Teichroeb, Julie Annette; Smeltzer, Eve Ann

    2018-01-01

    Animal paths are analogous to intractable mathematical problems like the Traveling Salesman Problem (TSP) and the shortest path problem (SPP). Both the TSP and SPP require an individual to find the shortest path through multiple targets but the TSP demands a return to the start, while the SPP does not. Vervet monkeys are very efficient in solving TSPs but this species is a multiple central place forager that does not always return to the same sleeping site and thus theoretically should be selected to find solutions to SPPs rather than TSPs. We examined path choice by wild vervets in an SPP experimental array where the shortest paths usually differed from those consistent with common heuristic strategies, the nearest-neighbor rule (NNR-go to the closest resource that has not been visited), and the convex hull (put a mental loop around sites, adding inner targets in order of distance from the edge)-an efficient strategy for TSPs but not SPPs. In addition, humans solving SPPs use an initial segment strategy (ISS-choose the straightest path at the beginning, only turning when necessary) and we looked at vervet paths consistent with this strategy. In 615 trials by single foragers, paths usually conformed to the NNR and rarely the slightly more efficient convex hull, supporting that vervets may be selected to solve SPPs. Further, like humans solving SPPs, vervets showed a tendency to use the ISS. Paths consistent with heuristics dropped off sharply, and use of the shortest path increased, when heuristics led to longer paths showing trade-offs in efficiency versus cognitive load. Two individuals out of 17, found the shortest path most often, showing inter-individual variation in path planning. Given support for the NNR and the ISS, we propose a new rule-of-thumb termed the "region heuristic" that vervets may apply in multi-destination routes.

  17. Mercury sodium exospheric emission as a proxy for solar perturbations transit

    Science.gov (United States)

    Orsini, S.; Mangano, V.; Milillo, A.; Plainaki, C.; Mura, A.; Raines, J. M.; Laurenza, M.; De Angelis, E.; Rispoli, R.; Lazzarotto, F.; Aronica, A.

    2017-12-01

    The first evidence at Mercury of direct relation between ICME transit and Na exosphere dynamics is presented, suggesting that Na emission, observed from ground, could be a proxy of planetary space weather at Mercury. The link existing between the dayside exosphere Na patterns and the solar wind-magnetosphere-surface interactions is investigated. This goal is pursued by analyzing the Na intensity hourly images, as observed by the ground-based THEMIS solar telescope (Mangano et al., 2015*) during 10 selected periods between 2012 and 2013 (with seeing, σ 10.1016/j.pss.2015.04.001, 2015.

  18. Satellite Altimeters and Gravimeters as Proxy of the Indonesian Throughflow

    Science.gov (United States)

    Susanto, R. D.; Song, Y. T.

    2014-12-01

    The Indonesian Throughflow (ITF), the only pathway for interocean exchange between the Pacific to the Indian Ocean, plays an important role in global ocean circulation and climate. Yet, continuous ITF measurement is difficult and expensive. We demonstrate a plausible approach to derive the ITF transport proxy using satellite altimetry sea surface height (SSH), gravimetry ocean bottom pressure (OBP) data, in situ measurements from the Makassar Strait from 1996-1998 and 2004-2009, and a theoretical formulation. We first identified the optimal locations in the Pacific and Indian Ocean based on the optimal correlation between the ITF transport through the Makassar Strait and the pressure gradients, represented by the SSH and OBP differences between the Pacific and Indian Oceans at a 1° x 1° horizontal resolution. These geographical locations (centred at off-equatorial in the western Pacific Ocean and centred at along the equator in the eastern Indian Ocean) that control the strength and variability of the ITF transport in the Makassar Strait differ from early studies. The proxy time series follow the observation time series quite well, resolving the intraseasonal, monsoonal, and interannual signals with the 1993-2011 annual mean proxy transport of 11.6 ± 3.2 Sv. Our formulation provides a continuous approach to derive the ITF proxy as long as the satellite data are available. Such a continuous record would be difficult to achieve by in situ measurements alone due to logistical and financial challenges. Ideally, the proxy can be used to complement or fill in the gaps of the observations for a continuous ITF proxy for better understanding the ocean climate and validating ocean circulation models.

  19. The Intra-Industry Effects of Proxy Contests

    OpenAIRE

    Fang Chen; Jian Huang; Han Yu

    2018-01-01

    This paper is the first study on the intra-industry effects of proxy contests. Using a sample of proxy contests from January 1988 through December 2008, we identify a striking cross-sectional difference in market reaction to the target companies. As much as 61% of the target firms have a significant positive cumulative abnormal return (CARs) in the period (‒10, +10) around the announcement day, while 39% of the target firms have the negative CARs in the same event window. Moreover, we find th...

  20. 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...

  1. Multi-gene phylogeny of the genus Lobaria: Evidence of species-pair and allopatric cryptic speciation in East Asia.

    Science.gov (United States)

    Cornejo, Carolina; Scheidegger, Christoph

    2015-12-01

    Accurate species delimitation has critical implications for ecological and conservation studies. The lichen genus Lobaria is widely distributed in old-growth forests. Particularly in East Asia, this genus includes many rare and poorly known taxa that are circumscribed as morpho- or chemospecies, as well as species-pairs. To critically examine the relationships between species identified via morphological and chemical criteria, phylogenetic species recognition (PSR) was applied to the genus Lobaria. Morphological and chemical patterns of 87 individuals were examined and three independent nuclear loci were sequenced. The East Asian L. meridionalis-group was additionally studied using split decomposition and haplotype network analysis. The genus Lobaria and most of its species were strongly supported statistically. Split decomposition and haplotype networks suggest complex evolutionary histories of species within the East Asian L. meridionalis-group. Phylogenetic analyses confirmed the monophyly of the genus Lobaria, including L. anomala. Within Lobaria, three major clades were found. These clades associate with different photobionts and comprise 18 known species and 5 undescribed species. Several chemical compounds were found to be neither stable nor invariant characters. Some taxa of the L. meridionalis-group appear to be monophyletic but remain as allopatric cryptic species. In three clades, this study found evidence for diversification processes between isidiate and nonisidiate specimens (species-pair). These findings are discussed in the context of evolutionary hypotheses for speciation processes. © 2015 Botanical Society of America.

  2. Promoting Evidence to Policy Link on the Control of Infectious Diseases of Poverty in Nigeria: Outcome of A Multi-Stakeholders Policy Dialogue

    Science.gov (United States)

    Uneke, Chigozie Jesse; Ebeh Ezeoha, Abel; Uro-Chukwu, Henry; Ezeonu, Chinonyelum Thecla; Ogbu, Ogbonnaya; Onwe, Friday; Edoga, Chima

    2015-01-01

    Background: In Nigeria, malaria, schistosomiasis and lymphatic filariasis are among infectious diseases of poverty (IDP) with severe health burden and require effective policy strategies for their control. In this study, we investigated the value of policy brief and policy dialogue as excellent policymaking mechanisms that enable policymakers to adapt effective evidence informed policy for IDP control. Methods: A policy brief was developed on the control of malaria, schistosomiasis and lymphatic filariasis and subjected to deliberations in a one-day multi-stakeholder policy dialogue held in Ebonyi State Nigeria. A modified cross sectional intervention study design was used in this investigation. Structured pre-tested questionnaires were used to evaluate the policy brief document and policy dialogue process at the end of the policy dialogue. Results: Forty-seven policymakers participated in the dialogue. An analysis of the response on the policy brief regarding context, different features of the problem; policy options and key implementation considerations indicated the mean ratings (MNRs) mostly ranged from 6.40-6.85 on 7 point scale. The over-all assessment of the policy brief had MNR at 6.54. The analysis of the response on the policy dialogue regarding the level of priority of policy issue, opportunity to discuss different features of the problem and options for addressing the problem, and the MNRs mostly ranged from 6.50-6.82. The overall assessment of the policy dialogue had MNR at 6.72. Conclusion: Policy dialogues can allow research evidence to be considered together with views, experiences and tacit knowledge of policymakers and can enhance evidence-to-policy link. PMID:26290826

  3. Model simulations and proxy-based reconstructions for the European region in the past millennium (Invited)

    Science.gov (United States)

    Zorita, E.

    2009-12-01

    One of the objectives when comparing simulations of past climates to proxy-based climate reconstructions is to asses the skill of climate models to simulate climate change. This comparison may accomplished at large spatial scales, for instance the evolution of simulated and reconstructed Northern Hemisphere annual temperature, or at regional or point scales. In both approaches a 'fair' comparison has to take into account different aspects that affect the inevitable uncertainties and biases in the simulations and in the reconstructions. These efforts face a trade-off: climate models are believed to be more skillful at large hemispheric scales, but climate reconstructions are these scales are burdened by the spatial distribution of available proxies and by methodological issues surrounding the statistical method used to translate the proxy information into large-spatial averages. Furthermore, the internal climatic noise at large hemispheric scales is low, so that the sampling uncertainty tends to be also low. On the other hand, the skill of climate models at regional scales is limited by the coarse spatial resolution, which hinders a faithful representation of aspects important for the regional climate. At small spatial scales, the reconstruction of past climate probably faces less methodological problems if information from different proxies is available. The internal climatic variability at regional scales is, however, high. In this contribution some examples of the different issues faced when comparing simulation and reconstructions at small spatial scales in the past millennium are discussed. These examples comprise reconstructions from dendrochronological data and from historical documentary data in Europe and climate simulations with global and regional models. These examples indicate that the centennial climate variations can offer a reasonable target to assess the skill of global climate models and of proxy-based reconstructions, even at small spatial scales

  4. Enhancing evidence-based diabetes and chronic disease control among local health departments: a multi-phase dissemination study with a stepped-wedge cluster randomized trial component.

    Science.gov (United States)

    Parks, Renee G; Tabak, Rachel G; Allen, Peg; Baker, Elizabeth A; Stamatakis, Katherine A; Poehler, Allison R; Yan, Yan; Chin, Marshall H; Harris, Jenine K; Dobbins, Maureen; Brownson, Ross C

    2017-10-18

    The rates of diabetes and prediabetes in the USA are growing, significantly impacting the quality and length of life of those diagnosed and financially burdening society. Premature death and disability can be prevented through implementation of evidence-based programs and policies (EBPPs). Local health departments (LHDs) are uniquely positioned to implement diabetes control EBPPs because of their knowledge of, and focus on, community-level needs, contexts, and resources. There is a significant gap, however, between known diabetes control EBPPs and actual diabetes control activities conducted by LHDs. The purpose of this study is to determine how best to support the use of evidence-based public health for diabetes (and related chronic diseases) control among local-level public health practitioners. This paper describes the methods for a two-phase study with a stepped-wedge cluster randomized trial that will evaluate dissemination strategies to increase the uptake of public health knowledge and EBPPs for diabetes control among LHDs. Phase 1 includes development of measures to assess practitioner views on and organizational supports for evidence-based public health, data collection using a national online survey of LHD chronic disease practitioners, and a needs assessment of factors influencing the uptake of diabetes control EBPPs among LHDs within one state in the USA. Phase 2 involves conducting a stepped-wedge cluster randomized trial to assess effectiveness of dissemination strategies with local-level practitioners at LHDs to enhance capacity and organizational support for evidence-based diabetes prevention and control. Twelve LHDs will be selected and randomly assigned to one of the three groups that cross over from usual practice to receive the intervention (dissemination) strategies at 8-month intervals; the intervention duration for groups ranges from 8 to 24 months. Intervention (dissemination) strategies may include multi-day in-person workshops, electronic

  5. Data Cleaning Methods for Client and Proxy Logs

    NARCIS (Netherlands)

    Weinreich, H.; Obendorf, H.; Herder, E.; Edmonds, A.; Hawkey, K.; Kellar, M.; Turnbull, D.

    2006-01-01

    In this paper we present our experiences with the cleaning of Web client and proxy usage logs, based on a long-term browsing study with 25 participants. A detailed clickstream log, recorded using a Web intermediary, was combined with a second log of user interface actions, which was captured by a

  6. Comparison of independent proxies in the reconstruction of deep ...

    African Journals Online (AJOL)

    Independent proxies were assessed in two Late Quaternary sediment cores from the eastern South Atlantic to compare deep-water changes during the last 400 kyr. ... is exclusively observed during interglacials, with maximum factor loadings in ... only slightly without a significant glacial-interglacial pattern, as measured in a ...

  7. TEX86 paleothermometry : proxy validation and application in marine sediments

    NARCIS (Netherlands)

    Huguet, C.

    2007-01-01

    Determination of past sea surface temperature (SST) is of primary importance for the reconstruction of natural climatic changes, modelling of climate and reconstruction of ocean circulation. Recently, a new SST proxy was introduced, the TetraEther indeX of lipids with 86 carbons (TEX86), which is

  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. 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…

  10. 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.

  11. 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…

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

    KAUST Repository

    McCrae, James; Singh, Karan S.; Mitra, Niloy J.

    2011-01-01

    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

  13. The conceptualization and measurement of cognitive reserve using common proxy indicators: Testing some tenable reflective and formative models.

    Science.gov (United States)

    Ikanga, Jean; Hill, Elizabeth M; MacDonald, Douglas A

    2017-02-01

    The examination of cognitive reserve (CR) literature reveals a lack of consensus regarding conceptualization and pervasive problems with its measurement. This study aimed at examining the conceptual nature of CR through the analysis of reflective and formative models using eight proxies commonly employed in the CR literature. We hypothesized that all CR proxies would significantly contribute to a one-factor reflective model and that educational and occupational attainment would produce the strongest loadings on a single CR factor. The sample consisted of 149 participants (82 male/67 female), with 18.1 average years of education and ages of 45-99 years. Participants were assessed for eight proxies of CR (parent socioeconomic status, intellectual functioning, level of education, health literacy, occupational prestige, life leisure activities, physical activities, and spiritual and religious activities). Primary statistical analyses consisted of confirmatory factor analysis (CFA) to test reflective models and structural equation modeling (SEM) to evaluate multiple indicators multiple causes (MIMIC) models. CFA did not produce compelling support for a unitary CR construct when using all eight of our CR proxy variables in a reflective model but fairly cogent evidence for a one-factor model with four variable proxies. A second three-factor reflective model based upon an exploratory principal components analysis of the eight proxies was tested using CFA. Though all eight indicators significantly loaded on their assigned factors, evidence in support of overall model fit was mixed. Based upon the results involving the three-factor reflective model, two alternative formative models were developed and evaluated. While some support was obtained for both, the model in which the formative influences were specified as latent variables appeared to best account for the contributions of all eight proxies to the CR construct. While the findings provide partial support for our

  14. Tropical Hydroclimate Change during Heinrich Stadial 1: An Integrative Proxy-Model Synthesis

    Science.gov (United States)

    Lawman, A. E.; Sun, T.; Shanahan, T. M.; Di Nezio, P. N.; Gomez, K.; Piatrunia, N.; Sun, C.; Wu, X.; Kageyama, M.; Merkel, U.; Otto-Bliesner, B. L.; Abe-Ouchi, A.; Lohmann, G.; Singarayer, J. S.

    2017-12-01

    We explore the response of tropical climate to abrupt cooling of the North Atlantic (NA) during Heinrich Stadial 1 (HS1) combining paleoclimate proxies with model simulations. A total of 146 published paleoclimate records from tropical locations are used to categorize whether HS1 was wetter, drier, or unchanged relative to a deglacial baseline state. Only records with sufficient resolution to resolve HS1 and sufficient length to characterize the deglacial trend are considered. This synthesis reveals large-scale patterns of hydroclimate change relative to glacial conditions, confirming previously reported weaker Indian summer monsoon, a wetter southern Africa, and drying over the Caribbean. Our synthesis also reveals large-scale drying over the Maritime continent as well as wetter conditions in northern Australia and southern tropical South America. Our reinterpretation of the available proxy data reveals far more complexity and uncertainties for equatorial East Africa, a region that appears to straddle a pattern of dryer conditions to the north and wetter conditions to the south. Overall, these patterns of hydroclimate change depart from a southward shift of the Inter Tropical Convergence Zone (ITCZ), particularly outside the tropical Atlantic. We explore mechanisms driving these changes using a multi-model ensemble of "hosing" simulations performed relative to glacial conditions. The models show robust weakening of the Afro-Asian Monsoon, which we attribute to ventilation of colder mid-latitude air. Not all models simulate the remaining patterns inferred from the proxy data. The best-agreeing models indicate that cooling over the tropical NA and the Caribbean may be essential to communicate the response to the global tropics. This response can induce warming over the tropical South Atlantic via the wind-evaporation-SST feedback, driving wetter conditions in South Africa and tropical South America. Cooling over the Caribbean is communicated to the Pacific over the

  15. 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

    2014-01-01

    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

  16. Proxy-Produced Ethnographic Work: What Are the Problems, Issues, and Dilemmas Arising from Proxy-Ethnography?

    Science.gov (United States)

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

    2018-01-01

    This article addresses the implications of researcher-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. Although there are clear advantages, the specific relations and positions arising…

  17. Evaluation of the sea ice proxy IP against observational and diatom proxy data in the SW Labrador Sea

    DEFF Research Database (Denmark)

    Weckström, K.; Andersen, M.L.; Kuijpers, A.

    2013-01-01

    The recent rapid decline in Arctic sea ice cover has increased the need to improve the accuracy of the sea ice component in climate models and to provide detailed long-term sea ice concentration records, which are only available via proxy data. Recently, the highly branched isoprenoid IP25...

  18. Deciphering Late-Pleistocence landscape evolution: linking proxies by combining pedo-stratigraphy and luminescence dating

    Science.gov (United States)

    Kreutzer, Sebastian; Meszner, Sascha; Faust, Dominik; Fuchs, Markus

    2014-05-01

    Interpreting former landscape evolution asks for understanding the processes that sculpt such landforms by means of deciphering complex systems. For reconstructing terrestrial Quaternary environments based on loess archives this might be considered, at least, as a three step process: (1) Identifying valuable records in appropriate morphological positions in a previously defined research area, (2) analysing the profiles by field work and laboratory methods and finally (3) linking the previously considered pseudo-isolated systems to set up a comprehensive picture. Especially the first and the last step might bring some pitfalls, as it is tempting to specify single records as pseudo-isolated, closed systems. They might be, with regard to their preservation in their specific morphological position, but in fact they are part of a complex, open system. Between 2008 and 2013, Late-Pleistocene loess archives in Saxony have been intensively investigated by field and laboratory methods. Linking pedo- and luminescence dating based chronostratigraphies, a composite profile for the entire Saxonian Loess Region has been established. With this, at least, two-fold approach we tried to avoid misinterpretations that might appear when focussing on one standard profile in an open morphological system. Our contribution focuses on this multi-proxy approach to decipher the Late-Pleistocene landscape evolution in the Saxonian Loess Region. Highlighting the challenges and advantages of combining different methods, we believe that (1) this multi-proxy approach is without alternative, (2) the combination of different profiles may simplify the more complex reality, but it may be a useful generalisation to understand and reveal the stratigraphical significance of the landscape evolution in this region.

  19. Calibrating multiple isotopic proxies in a modern aragonite speleothem from northeast India

    Science.gov (United States)

    Ronay, E.; Oster, J. L.; Sharp, W. D.; Marks, N.; Erhardt, A.; Breitenbach, S. F. M.

    2017-12-01

    Uranium, strontium, and calcium isotope ratios in calcite speleothems are used as proxies for water-soil-rock interactions and prior calcite precipitation, and thus provide information about effective rainfall amount variations, primarily in semi-arid or highly seasonal regions. However, less is known about how these proxies function in humid regions and in aragonite speleothems. In this study, we use meteorological data to calibrate (234U/238U)i and 87Sr/86Sr in a modern aragonite speleothem from northeast India, the rainiest place on Earth, to determine how these proxies reflect effective monsoon rainfall amount. MAW-0201 is an annually laminated aragonite stalagmite that grew from 1960-2013 in Mawmluh Cave, Meghalaya, India. Rainfall here is extremely seasonal due to the Indian Summer Monsoon (ISM), which brings several meters of rain to the region each summer, but with inter-annual variability in total rainfall. The δ18O in Mawmluh dripwater and speleothems reflects moisture source and transport, rather than rainfall amount. Variations in Mg, U, and Ba concentrations in MAW-0201 show seasonal and multi-annual variability. U and Mg are closely correlated, but multi-year periods show significant anti-correlation. The Mg and U distribution coefficients in calcite and aragonite indicate correlated periods are times of prior calcite precipitation (PCP) and anti-correlated periods are times of prior aragonite precipitation (PAP) in the epikarst. We use δ44/40Ca to test this hypothesis, as Ca isotopes fractionate differently during calcite and aragonite precipitation and speleothem δ44/40Ca will record unique PAP and PCP fingerprints. We propose such shifts from PCP to PAP reflect hydrologic variability and/or flow path changes, which provide a useful tool for understanding epikarst hydrology but may also be a complicating factor in speleothem-based paleoclimate interpretations. Preliminary (234U/238U)i (always <1) and 87Sr/86Sr spanning 1991-2009 each show

  20. Geomorphic Proxies to Test Strain Accommodation in Southwestern Puerto Rico from Digital Elevation Models

    Science.gov (United States)

    Barrios Galindez, I. M.; Xue, L.; Laó-Dávila, D. A.

    2017-12-01

    The Puerto Rico and the Virgin Island microplate is located in at the northeastern corner of the Caribbean plate boundary with North America is placed within an oblique subduction zone in which strain patterns remain unresolved. Seismic hazard is a major concern in the region as seen from the seismic history of the Caribbean-North America plate boundary zone. Most of the tectonic models of the microplate show the accommodation of strain occurring offshore, despite evidence from seismic activity, trench studies, and geodetic studies suggesting the existence of strain accomodation in southwest Puerto Rico. These studies also suggest active faulting specially in the western part of the island, but limited work has been done regarding their mechanism. Therefore, this work aims to define and map these active faults in western Puerto Rico by integrating data from analysis of fluvial terrains, and detailed mapping using digital elevation model (DEM) extracted from Shuttle Radar Topography Mission (SRTM) and LIDAR data. The goal is to (1) identify structural features such as surface lineaments and fault scarps for the Cerro Goden fault, South Lajas fault, and other active faults in the western of Puerto Rico, (2) correlate these information with the distribution pattern and values of the geomorphic proxies, including Chi integral (χ), normalized steepness (ksn) and Asymmetric factor (AF). Our preliminary results from geomorphic proxies and Lidar data provide some insight of the displacement and stage of activities of these faults (e.g. Boqueron-Punta Malva Fault and Cerro Goden fault). Also, the anomaly of the geomorphic proxies generally correlate with the locations of the landslides in the southwestern Puerto Rico. The geomorphic model of this work include new information of active faulting fundamental to produce better seismic hazards maps. Additionally, active tectonics studies are vital to issue and adjust construction buildings codes and zonification codes.

  1. Evaluation of proxy-based millennial reconstruction methods

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Terry C.K.; Tsao, Min [University of Victoria, Department of Mathematics and Statistics, Victoria, BC (Canada); Zwiers, Francis W. [Environment Canada, Climate Research Division, Toronto, ON (Canada)

    2008-08-15

    A range of existing statistical approaches for reconstructing historical temperature variations from proxy data are compared using both climate model data and real-world paleoclimate proxy data. We also propose a new method for reconstruction that is based on a state-space time series model and Kalman filter algorithm. The state-space modelling approach and the recently developed RegEM method generally perform better than their competitors when reconstructing interannual variations in Northern Hemispheric mean surface air temperature. On the other hand, a variety of methods are seen to perform well when reconstructing surface air temperature variability on decadal time scales. An advantage of the new method is that it can incorporate additional, non-temperature, information into the reconstruction, such as the estimated response to external forcing, thereby permitting a simultaneous reconstruction and detection analysis as well as future projection. An application of these extensions is also demonstrated in the paper. (orig.)

  2. Adaptive proxy map server for efficient vector spatial data rendering

    Science.gov (United States)

    Sayar, Ahmet

    2013-01-01

    The rapid transmission of vector map data over the Internet is becoming a bottleneck of spatial data delivery and visualization in web-based environment because of increasing data amount and limited network bandwidth. In order to improve both the transmission and rendering performances of vector spatial data over the Internet, we propose a proxy map server enabling parallel vector data fetching as well as caching to improve the performance of web-based map servers in a dynamic environment. Proxy map server is placed seamlessly anywhere between the client and the final services, intercepting users' requests. It employs an efficient parallelization technique based on spatial proximity and data density in case distributed replica exists for the same spatial data. The effectiveness of the proposed technique is proved at the end of the article by the application of creating map images enriched with earthquake seismic data records.

  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 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.

  5. 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.

  6. Accuracy of Caregiver Proxy Reports of Home Care Service Use.

    Science.gov (United States)

    Chappell, Neena L; Kadlec, Helena

    2016-12-01

    Although much of the research on service use by older adults with dementia relies on proxy reports by informal caregivers, little research assesses the accuracy of these reports, and that which does exist, does not focus on home care services. This brief report compares proxy reports by family caregivers to those with dementia with provincial Ministry of Health records collected for payment and monitoring. The four home care services examined include home nursing care, adult day care, home support, and respite care. Data come from a province-wide study of caregivers in British Columbia, Canada. Caregiver reports are largely consistent with Ministry records, ranging from 81.0% agreement for home support to 96.6% for respite care. Spouses living with the care recipient (the vast majority of the sample) are the most accurate. Others, whether living with the care recipient or not, have only a 50-50 chance of being correct.

  7. 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.

  8. Testing New Proxies for Photosymbiosis in the Fossil Record

    Science.gov (United States)

    Tornabene, C.; Martindale, R. C.; Schaller, M. F.

    2015-12-01

    Photosymbiosis is a mutualistic relationship that many corals have developed with dinoflagellates called zooxanthellae. The dinoflagellates, of the genus Symbiodinium, photosynthesize and provide corals with most of their energy, while in turn coral hosts live in waters where zooxanthellae have optimal exposure to sunlight. Thanks to this relationship, symbiotic corals calcify faster than non-symbiotic corals. Photosymbiosis is therefore considered the evolutionary innovation that allowed corals to become major reef-builders through geological time.This relationship is extremely difficult to study. Zooxanthellae, which are housed in the coral tissue, are not preserved in fossil coral skeletons, thus determining whether corals had symbionts requires a robust proxy. In order to address this critical question, the goal of this research is to test new proxies for ancient photosymbiosis. Currently the project is focused on assessing the nitrogen (δ15N) isotopes of corals' organic matrices, sensu Muscatine et al. (2005), as well as carbon and oxygen (δ13C, δ18O) isotopes of fossil coral skeletons. Samples from Modern, Pleistocene, Oligocene and Triassic coral skeletons were analyzed to test the validity of these proxies. Coral samples comprise both (interpreted) symbiotic and non-symbiotic fossil corals from the Oligocene and Triassic as well as symbiotic fossil corals from the Modern and Pleistocene to corroborate our findings with the results of Muscatine et al. (2005). Samples were tested for diagenesis through petrographic and scanning electron microscope (SEM) analyses to avoid contamination. Additionally, a novel technique that has not yet been applied to the fossil record was tested. The technique aims to recognize dinosterol, a dinoflagellate biomarker, in both modern and fossil coral samples. The premise of this proxy is that symbiotic corals should contain the dinoflagellate biomarker, whereas those lacking symbionts should lack dinosterol. Results from this

  9. Evaluation of Organic Proxies for Quantifying Past Primary Productivity

    Science.gov (United States)

    Raja, M.; Rosell-Melé, A.; Galbraith, E.

    2017-12-01

    Ocean primary productivity is a key element of the marine carbon cycle. However, its quantitative reconstruction in the past relies on the use of biogeochemical models as the available proxy approaches are qualitative at best. Here, we present an approach that evaluates the use of phytoplanktonic biomarkers (i.e. chlorins and alkenones) as quantitative proxies to reconstruct past changes in marine productivity. We compare biomarkers contents in a global suite of core-top sediments to sea-surface chlorophyll-a abundance estimated by satellites over the last 20 years, and the results are compared to total organic carbon (TOC). We also assess satellite data and detect satellite limitations and biases due to the complexity of optical properties and the actual defined algorithms. Our findings show that sedimentary chlorins can be used to track total sea-surface chlorophyll-a abundance as an indicator for past primary productivity. However, degradation processes restrict the application of this proxy to concentrations below a threshold value (1µg/g). Below this threshold, chlorins are a useful tool to identify reducing conditions when used as part of a multiproxy approach to assess redox sedimentary conditions (e.g. using Re, U). This is based on the link between anoxic/disoxic conditions and the flux of organic matter from the sea-surface to the sediments. We also show that TOC is less accurate than chlorins for estimating sea-surface chlorophyll-a due to the contribution of terrigenous organic matter, and the different degradation pathways of all organic compounds that TOC includes. Alkenones concentration also relates to primary productivity, but they are constrained by different processes in different regions. In conclusion, as lons as specific constraints are taken into account, our study evaluates the use of chlorins and alkenones as quantitative proxies of past primary productivity, with more accuracy than by using TOC.

  10. Analisis Algoritma Pergantian Cache Pada Proxy Web Server Internet Dengan Simulasi

    OpenAIRE

    Nurwarsito, Heru

    2007-01-01

    Pertumbuhan jumlah client internet dari waktu ke waktu terus bertambah, maka respon akses internet menjadi semakin lambat. Untuk membantu kecepatan akses tersebut maka diperlukan cache pada Proxy Server. Penelitian ini bertujuan untuk menganalisis performansi Proxy Server pada Jaringan Internet terhadap penggunaan algoritma pergantian cache-nya.Analisis Algoritma Pergantian Cache Pada Proxy Server didesain dengan metoda pemodelan simulasi jaringan internet yang terdiri dari Web server, Proxy ...

  11. 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.

  12. 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.

  13. 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.

  14. δ15N as a proxy for historic anthropogenic nitrogen loading in Charleston Harbor, SC, USA

    Science.gov (United States)

    Payne, T. N.; Andrus, C. F. T.

    2015-12-01

    Bivalve shell geochemistry can serve as a useful indicator of changes in coastal environments. There is increasing interest in developing paleoenvironmental proxies from mollusk shell organic components. Numerous studies have focused on how the δ15N obtained from bivalve tissues can be used to trace present-day wastewater input into estuaries. However, comparatively little attention has been paid to tracing the impact of anthropogenic nitrogen loading into estuaries over time. By measuring historic levels of δ15N in the organic fraction of oyster shells (Crassostrea virginica) from archaeological sites around Charleston Harbor and comparing those levels to the δ15N content of modern shells, it is possible to assess how nitrogen has fluctuated historically in the area. Whole-shell samples from the Late Archaic Period (~3000-4000 BP, Late Woodland Period (~1400-800 BP), 18th and 19th centuries, and modern controls were measured for %N and d15N. Evidence of increased anthropogenic input of N is expected to begin in the early historic period based on similar analysis in Chesapeake Bay. More ancient samples may give insight into baseline conditions prior to recent population growth and industrialization. This information could help understand how large-scale anthropogenic nitrogen loading has affected coastal ecosystems over time and guide future remediation. Furthermore, this project will help refine and improve this novel proxy of past environmental conditions.

  15. SOLAR CYCLE PROPAGATION, MEMORY, AND PREDICTION: INSIGHTS FROM A CENTURY OF MAGNETIC PROXIES

    International Nuclear Information System (INIS)

    Muñoz-Jaramillo, Andrés; DeLuca, Edward E.; Dasi-Espuig, María; Balmaceda, Laura A.

    2013-01-01

    The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. A major contributor to the disagreement is the lack of direct long-term databases covering different components of the solar magnetic field (toroidal versus poloidal). Here, we use sunspot area and polar faculae measurements spanning a full century (as our toroidal and poloidal field proxies) to study solar cycle propagation, memory, and prediction. Our results substantiate predictions based on the polar magnetic fields, whereas we find sunspot area to be uncorrelated with cycle amplitude unless multiplied by area-weighted average tilt. This suggests that the joint assimilation of tilt and sunspot area is a better choice (with aims to cycle prediction) than sunspot area alone, and adds to the evidence in favor of active region emergence and decay as the main mechanism of poloidal field generation (i.e., the Babcock-Leighton mechanism). Finally, by looking at the correlation between our poloidal and toroidal proxies across multiple cycles, we find solar cycle memory to be limited to only one cycle.

  16. 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

  17. Analysis of Quality of Proxy Questions in Health Surveys by Behavior Coding

    NARCIS (Netherlands)

    Benitez, I.; Padilla, J.L.; Ongena, Yfke

    2012-01-01

    The aim of this study is to show how to analyze the quality of questions for proxy informants by means of behavior coding. Proxy questions can undermine survey data quality because of the fact that proxies respond to questions on behalf of other people. Behavior coding can improve questions by

  18. The design and implementation about the project of optimizing proxy servers

    International Nuclear Information System (INIS)

    Wu Ling; Liu Baoxu

    2006-01-01

    Proxy server is an important facility in the network of an organization, which play an important role in security and access control and accelerating access of Internet. This article introduces the action of proxy servers, and expounds the resolutions to optimize proxy servers at IHEP: integration, dynamic domain name resolves and data synchronization. (authors)

  19. Some Proxy Signature and Designated verifier Signature Schemes over Braid Groups

    OpenAIRE

    Lal, Sunder; Verma, Vandani

    2009-01-01

    Braids groups provide an alternative to number theoretic public cryptography and can be implemented quite efficiently. The paper proposes five signature schemes: Proxy Signature, Designated Verifier, Bi-Designated Verifier, Designated Verifier Proxy Signature And Bi-Designated Verifier Proxy Signature scheme based on braid groups. We also discuss the security aspects of each of the proposed schemes.

  20. Stable carbon isotope fractionation in pollen of Atlas cedar: first steps towards a new palaeoecological proxy for Northwest Africa

    Science.gov (United States)

    Bell, Benjamin; Fletcher, William; Ryan, Peter; Grant, Helen; Ilmen, Rachid

    2016-04-01

    Analysis of stable carbon isotopes can provide information on climate and the environmental conditions at different growth stages of the plant, both past and present. Carbon isotope discrimination in plant tissue is already well understood, and can be used as a drought stress indicator for semi-arid regions. Stable carbon isotope ratios measured directly on pollen provides the potential for the development of long-term environmental proxies (spanning thousands of years), as pollen is well preserved in the environment. Atlas Cedar (Cedrus atlantica Endl. Manetti ex Carrière), is an ideal test case to develop a pollen stable carbon isotope proxy. The tree grows across a wide altitudinal and climatic range and is extremely sensitive to moisture availability. The pollen is abundant, and easily identifiable to the species level in pollen analysis because different cedar species are geographically confined to different regions of the world. In 2015 we sampled 76 individual cedar trees across latitudinal, altitudinal and environmental gradients, highly focused on the Middle Atlas region of Morocco, with 25 additional samples from botanical gardens across Europe and the US to extend these gradients. Here, we report new stable carbon isotope data from pollen, leaf and stem wood from these samples with a view to assessing and quantifying species-specific fractionation effects associated with pollen production. The isotopic response of individual trees at local and wider geographical scales to altitude and climatic conditions is presented. This research forms part of an ongoing PhD project working to develop and calibrate a modern carbon isotope proxy in Atlas cedar pollen, which can ultimately be applied to fossil sequences and complement existing multi-proxy records (e.g. pollen analysis in lake sediments, tree-rings).

  1. Lava delta deformation as a proxy for submarine slope instability

    Science.gov (United States)

    Di Traglia, Federico; Nolesini, Teresa; Solari, Lorenzo; Ciampalini, Andrea; Frodella, William; Steri, Damiano; Allotta, Benedetto; Rindi, Andrea; Marini, Lorenzo; Monni, Niccolò; Galardi, Emanuele; Casagli, Nicola

    2018-04-01

    the 30 December 2002 landslide, which involved the lava delta and its surrounding areas. InSAR data provided the post-effusive deformation field after the 2007 and 2014 flank eruptions, whereas LEM results highlighted that the accumulation of lava flows on the prone-to-failure SdF submarine slope is the main cause of the detected lava delta deformation. Lava delta instability, measured also at Pico Island (Azores) and Kilauea volcano (Hawaii), is evidence of the broader spectrum of instability phenomena that take place in the coastal or submarine area of the flanks of the volcanoes. At Kilauea, past lava deltas have moved faster than the surrounding slope and the recorded movements relate only to the collapses of the deltas themselves, producing rapid mass wasting near the coasts. In contrast, at Stromboli and Pico, lava deltas move at the same velocity as the surrounding slope. In these cases, the displacement at lava deltas can be considered as a proxy for the deformation of submarine slides. There are very few studies dealing with lava delta deformation, thus, the analysis presented in this work will benefit the monitoring of submarine slopes in other prone-to-failure coastal or island volcanic systems which have the potential to generate tsunamis.

  2. Peat humification and climate change: a multi-site comparison from mires in south-east Alaska

    Directory of Open Access Journals (Sweden)

    R.J. Payne

    2008-11-01

    Full Text Available Peatland records of Holocene palaeoclimate have been widely used in Europe. Their potential in western North America remains largely unexploited despite an abundance of candidate sites. Peat humification analysis is a widely used technique for palaeoclimatic inference from peatlands. This study attempts to demonstrate a climatic role in determining peat humification by comparing low-resolution peat humification records from five mires in south-east Alaska. Humification was determined by alkali extraction and colorimetry and records dated by radiocarbon and tephrochronology. Testate amoebae analysis was carried out across a major humification-inferred wet shift in three of the sites. The humification results show variability down the length of the cores but there is only limited agreement between records from different sites. Many general trends in the data appear to be out of phase and periods of proxy 'complacency' are shown. This study does not provide strong evidence for climatic forcing of humification in these sites. Methodological issues including possible problems with the age-depth models and the role of a peat-forming plant species signal in the humification data are discussed. The results support previous studies in suggesting the value of employing a multi-proxy, multi-site, and possibly multi-core approach in peat-based palaeoclimatology.

  3. Airborne LiDAR for the Detection of Archaeological Vegetation Marks Using Biomass as a Proxy

    Directory of Open Access Journals (Sweden)

    David Stott

    2015-02-01

    Full Text Available In arable landscapes, the airborne detection of archaeological features is often reliant on using the properties of the vegetation cover as a proxy for sub-surface features in the soil. Under the right conditions, the formation of vegetation marks allows archaeologists to identify and interpret archaeological features. Using airborne Laser Scanning, based on the principles of Light Detection and Ranging (LiDAR to detect these marks is challenging, particularly given the difficulties of resolving subtle changes in a low and homogeneous crop with these sensors. In this paper, an experimental approach is adopted to explore how these marks could be detected as variations in canopy biomass using both range and full waveform LiDAR data. Although some detection was achieved using metrics of the full waveform data, it is the novel multi-temporal method of using discrete return data to detect and characterise archaeological vegetation marks that is offered for further consideration. This method was demonstrated to be applicable over a range of capture conditions, including soils deemed as difficult (i.e., clays and other heavy soils, and should increase the certainty of detection when employed in the increasingly multi-sensor approaches to heritage prospection and management.

  4. Tracking variable sedimentation rates in orbitally forced paleoclimate proxy series

    Science.gov (United States)

    Li, M.; Kump, L. R.; Hinnov, L.

    2017-12-01

    This study addresses two fundamental issues in cyclostratigraphy: quantitative testing of orbital forcing in cyclic sedimentary sequences and tracking variable sedimentation rates. The methodology proposed here addresses these issues as an inverse problem, and estimates the product-moment correlation coefficient between the frequency spectra of orbital solutions and paleoclimate proxy series over a range of "test" sedimentation rates. It is inspired by the ASM method (1). The number of orbital parameters involved in the estimation is also considered. The method relies on the hypothesis that orbital forcing had a significant impact on the paleoclimate proxy variations, and thus is also tested. The null hypothesis of no astronomical forcing is evaluated using the Beta distribution, for which the shape parameters are estimated using a Monte Carlo simulation approach. We introduce a metric to estimate the most likely sedimentation rate using the product-moment correlation coefficient, H0 significance level, and the number of contributing orbital parameters, i.e., the CHO value. The CHO metric is applied with a sliding window to track variable sedimentation rates along the paleoclimate proxy series. Two forward models with uniform and variable sedimentation rates are evaluated to demonstrate the robustness of the method. The CHO method is applied to the classical Late Triassic Newark depth rank series; the estimated sedimentation rates match closely with previously published sedimentation rates and provide a more highly time-resolved estimate (2,3). References: (1) Meyers, S.R., Sageman, B.B., Amer. J. Sci., 307, 773-792, 2007; (2) Kent, D.V., Olsen, P.E., Muttoni, G., Earth-Sci. Rev.166, 153-180, 2017; (3) Li, M., Zhang, Y., Huang, C., Ogg, J., Hinnov, L., Wang, Y., Zou, Z., Li, L., 2017. Earth Plant. Sc. Lett. doi:10.1016/j.epsl.2017.07.015

  5. 350 Year Cloud Reconstruction Deduced from Northeast Caribbean Coral Proxies

    Science.gov (United States)

    Winter, A.; Sammarco, P. W.; Mikolajewicz, U.; Jury, M.; Zanchettin, D.

    2014-12-01

    Clouds are a major factor influencing the global climate and its response to external forcing through their implications for the global hydrological cycle, and hence for the planetary radiative budget. Clouds also contribute to regional climates and their variability through, e.g., the changes they induce in regional precipitation patterns. There have been very few studies of decadal and longer-term changes in cloud cover in the tropics and sub-tropics, both over land and the ocean. In the tropics, there is great uncertainty regarding how global warming will affect cloud cover. Observational satellite data are too short to unambiguously discern any temporal trends in cloud cover. Corals generally live in well-mixed coastal regions and can often record environmental conditions of large areas of the upper ocean. This is particularly the case at low latitudes. Scleractinian corals are sessile, epibenthic fauna, and the type of environmental information recorded at the location where the coral has been living is dependent upon the species of coral considered and proxy index of interest. Skeletons of scleractinian corals are considered to provide among the best records of high-resolution (sub-annual) environmental variability in the tropical and sub-tropical oceans. Zooxanthellate hermatypic corals in tropical and sub-tropical seas precipitate CaCO3 skeletons as they grow. This growth is made possible through the manufacture of CaCO3crystals, facilitated by the zooxanthellae. During the process of crystallization, the holobiont binds carbon of different isotopes into the crystals. Stable carbon isotope concentrations vary with a variety of environmental conditions. In the Caribbean, d13C in corals of the species Montastraea faveolata can be used as a proxy for changes in cloud cover. In this contribution, we will demonstrate that the stable isotope 13C varies concomitantly with cloud cover for the northeastern Caribbean region. Using this proxy we have been able to

  6. Polar cap index as a proxy for hemispheric Joule heating

    DEFF Research Database (Denmark)

    Chun, F.K.; Knipp, D.J.; McHarg, M.G.

    1999-01-01

    The polar cap (PC) index measures the level of geomagnetic activity in the polar cap based on magnetic perturbations from overhead ionospheric currents and distant field-aligned currents on the poleward edge of the nightside auroral oval. Because PC essentially measures the main sources of energy...... input into the polar cap, we propose to use PC as a proxy for the hemispheric Joule heat production rate (JH). In this study, JH is estimated from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. We fit hourly PC values to hourly averages of JH. Using a data base approximately...

  7. Improvement of a Quantum Proxy Blind Signature Scheme

    Science.gov (United States)

    Zhang, Jia-Lei; Zhang, Jian-Zhong; Xie, Shu-Cui

    2018-06-01

    Improvement of a quantum proxy blind signature scheme is proposed in this paper. Six-qubit entangled state functions as quantum channel. In our scheme, a trust party Trent is introduced so as to avoid David's dishonest behavior. The receiver David verifies the signature with the help of Trent in our scheme. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, delegation, signature and verification. Security analysis proves that our scheme has the properties of undeniability, unforgeability, anonymity and can resist some common attacks.

  8. Growth rates and geochemical proxies in Late Campanian bivalves - New insights from micro-X-ray Fluorescence mapping and numerical growth modelling

    Science.gov (United States)

    de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe

    2017-04-01

    Understanding the Late Cretaceous greenhouse climate is of vital importance for understanding present and future climate change. While a lot of good work has been done to reconstruct climate in this interesting period, most paleoclimatic studies have focused on long-term climate change[1]. Alternatively, multi-proxy records from marine bivalves provide us with a unique opportunity to study past climate on a seasonal scale. However, previous fossil bivalve studies have reported ambiguous results with regard to the interpretation of trace element and stable isotope proxies in marine bivalve shells[2]. One major problem in the interpretation of such records is the bivalve's vital effect and the occurrence of disequilibrium fractionation during bivalve growth. Both these problems are linked to the annual growth cycle of marine bivalves, which introduces internal effects on the incorporation of isotopes and trace elements into the shell[3]. Understanding this growth cycle in extinct bivalves is therefore of great importance for the interpretation of seasonal proxy records in their shells. In this study, three different species of extinct Late Campanian bivalves (two rudist species and one oyster species) that were found in the same stratigraphic interval are studied. Micro-X-Ray Fluorescence line scanning and mapping of trace elements such as Mg, Sr, S and Zn, calibrated by LA-ICP-MS measurements, is combined with microdrilled stable carbon and oxygen isotope analysis on the well-preserved part of the shells. Data of this multi-proxy study is compared with results from a numerical growth model written in the open-source statistics package R[4] and based on annual growth increments observed in the shells and shell thickness. This growth model is used together with proxy data to reconstruct rates of trace element incorporation into the shell and to calculate the mass balance of stable oxygen and carbon isotopes. In order to achieve this goal, 2D mapping of bivalve shell

  9. 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.

  10. Starspot variability as an X-ray radiation proxy

    Science.gov (United States)

    Arkhypov, Oleksiy V.; Khodachenko, Maxim L.; Lammer, Helmut; Güdel, Manuel; Lüftinger, Teresa; Johnstone, Colin P.

    2018-05-01

    Stellar X-ray emission plays an important role in the study of exoplanets as a proxy for stellar winds and as a basis for the prediction of extreme ultraviolet (EUV) flux, unavailable for direct measurements, which in their turn are important factors for the mass-loss of planetary atmospheres. Unfortunately, the detection thresholds limit the number of stars with the directly measured X-ray fluxes. At the same time, the known connection between the sunspots and X-ray sources allows using of the starspot variability as an accessible proxy for the stellar X-ray emission. To realize this approach, we analysed the light curves of 1729 main-sequence stars with rotation periods 0.5 X-ray to bolometric luminosity ratio Rx. As a result, the regressions for stellar X-ray luminosity Lx(P, Teff) and its related EUV analogue LEUV were obtained for the main-sequence stars. It was shown that these regressions allow prediction of average (over the considered stars) values of log (Lx) and log (LEUV) with typical errors of 0.26 and 0.22 dex, respectively. This, however, does not include the activity variations in particular stars related to their individual magnetic activity cycles.

  11. Attribute-Based Proxy Re-Encryption with Keyword Search

    Science.gov (United States)

    Shi, Yanfeng; Liu, Jiqiang; Han, Zhen; Zheng, Qingji; Zhang, Rui; Qiu, Shuo

    2014-01-01

    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 (), 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, 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 , and propose two concrete constructions for : key-policy and ciphertext-policy . 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. PMID:25549257

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

    Science.gov (United States)

    Shi, Yanfeng; Liu, Jiqiang; Han, Zhen; Zheng, Qingji; Zhang, Rui; Qiu, Shuo

    2014-01-01

    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.

  13. A Scalable proxy cache for Grid Data Access

    International Nuclear Information System (INIS)

    Cristian Cirstea, Traian; Just Keijser, Jan; Arthur Koeroo, Oscar; Starink, Ronald; Alan Templon, Jeffrey

    2012-01-01

    We describe a prototype grid proxy cache system developed at Nikhef, motivated by a desire to construct the first building block of a future https-based Content Delivery Network for grid infrastructures. Two goals drove the project: firstly to provide a “native view” of the grid for desktop-type users, and secondly to improve performance for physics-analysis type use cases, where multiple passes are made over the same set of data (residing on the grid). We further constrained the design by requiring that the system should be made of standard components wherever possible. The prototype that emerged from this exercise is a horizontally-scalable, cooperating system of web server / cache nodes, fronted by a customized webDAV server. The webDAV server is custom only in the sense that it supports http redirects (providing horizontal scaling) and that the authentication module has, as back end, a proxy delegation chain that can be used by the cache nodes to retrieve files from the grid. The prototype was deployed at Nikhef and tested at a scale of several terabytes of data and approximately one hundred fast cores of computing. Both small and large files were tested, in a number of scenarios, and with various numbers of cache nodes, in order to understand the scaling properties of the system. For properly-dimensioned cache-node hardware, the system showed speedup of several integer factors for the analysis-type use cases. These results and others are presented and discussed.

  14. Geo-social media as a proxy for hydrometeorological data for streamflow estimation and to improve flood monitoring

    Science.gov (United States)

    Restrepo-Estrada, Camilo; de Andrade, Sidgley Camargo; Abe, Narumi; Fava, Maria Clara; Mendiondo, Eduardo Mario; de Albuquerque, João Porto

    2018-02-01

    Floods are one of the most devastating types of worldwide disasters in terms of human, economic, and social losses. If authoritative data is scarce, or unavailable for some periods, other sources of information are required to improve streamflow estimation and early flood warnings. Georeferenced social media messages are increasingly being regarded as an alternative source of information for coping with flood risks. However, existing studies have mostly concentrated on the links between geo-social media activity and flooded areas. Thus, there is still a gap in research with regard to the use of social media as a proxy for rainfall-runoff estimations and flood forecasting. To address this, we propose using a transformation function that creates a proxy variable for rainfall by analysing geo-social media messages and rainfall measurements from authoritative sources, which are later incorporated within a hydrological model for streamflow estimation. We found that the combined use of official rainfall values with the social media proxy variable as input for the Probability Distributed Model (PDM), improved streamflow simulations for flood monitoring. The combination of authoritative sources and transformed geo-social media data during flood events achieved a 71% degree of accuracy and a 29% underestimation rate in a comparison made with real streamflow measurements. This is a significant improvement on the respective values of 39% and 58%, achieved when only authoritative data were used for the modelling. This result is clear evidence of the potential use of derived geo-social media data as a proxy for environmental variables for improving flood early-warning systems.

  15. Analyzing differences between patient and proxy on Patient Reported Outcomes in multiple sclerosis.

    Science.gov (United States)

    Sonder, Judith M; Holman, Rebecca; Knol, Dirk L; Bosma, Libertje V A E; Polman, Chris H; Uitdehaag, Bernard M J

    2013-11-15

    Proxy respondents, partners of multiple sclerosis (MS) patients, can provide valuable information on the MS patients' disease. In an earlier publication we found relatively good agreement on patient reported outcomes (PROs) measuring physical impact and functioning, but we found large differences on (neuro)psychological scales. We aim to identify patient and proxy related variables explaining differences between patients' and proxies' ratings on five PROs. We report on data from 175 MS patients and proxy respondents. Regression analyses were performed, using as dependent variable the mean differences on five scales: Physical and Psychological scale of the Multiple Sclerosis Impact Scale (MSIS-29), the Multiple Sclerosis Walking Scale (MSWS), Guy's Neurological Disability Scale (GNDS) and the Multiple Sclerosis Neuropsychological Screening Questionnaire (MSNQ). The independent variables were patient, proxy and disease related variables. Caregiver strain was significantly related to differences between patient and proxy scores for all five PROs. A higher level of patient anxiety on the HADS was linked to larger differences on all PROs except the GNDS. In addition, cognitive functioning, proxy depression, walking ability, proxy gender and MS related disability were contributing to the discrepancies. We found several patient and proxy factors that may contribute to discrepancies between patient and proxy scores on MS PROs. The most important factor is caregiver burden. © 2013 Elsevier B.V. All rights reserved.

  16. Development of DEMQOL-U and DEMQOL-PROXY-U: generation of preference-based indices from DEMQOL and DEMQOL-PROXY for use in economic evaluation.

    Science.gov (United States)

    Mulhern, B; Rowen, D; Brazier, J; Smith, S; Romeo, R; Tait, R; Watchurst, C; Chua, K-C; Loftus, V; Young, T; Lamping, D; Knapp, M; Howard, R; Banerjee, S

    2013-02-01

    system; phase 2 - general population valuation survey and modelling to produce values for every health state; phase 3 - patient/carer valuation survey; and phase 4 - application of measures to trial data. All four phases were successful and this report details this development process leading to the first condition-specific preference-based measures in dementia, an important new development in this field. The first limitation relates to the lack of an external data set to validate the DEMQOL-U and DEMQOL-Proxy-U classification systems. Throughout the development process we have made decisions about which methodology to use. There are other valid techniques that could be used and it is possible to criticise the choices that we have made. It is also possible that the use of a mild to moderate dementia sample has resulted in classification systems that do not fully reflect the challenges of severe dementia. The results presented are sufficiently encouraging to recommend that the DEMQOL instruments be used alongside a generic measure such as the European Quality of Life-5 Dimensions (EQ-5D) in future studies of interventions in dementia as there was evidence that they can be more sensitive for patients at the milder end of disease and some limited evidence that the person with dementia measure may be able to reflect deterioration. The National Institute for Health Research Health Technology Assessment programme.

  17. A multi-proxy chronological reconstruction of palaeosalinity in the eastern Limfjord, Denmark

    Science.gov (United States)

    Weiss, Gabriella; Reimer, Paula; Lewis, Jonathan

    2015-04-01

    The Jutland peninsula in northern Denmark is home to the Limfjord, one of the largest estuarine bodies of water in the region. Human inhabitance of the Limfjord's surrounding coastlines stretches back further than 7,800 cal BP, with anthropogenic influence on the landscape beginning approximately 6,000 cal BP. Understanding how the Limfjord as a system has changed throughout time is useful in comprehending subsistence patterns and anthropogenic influence. This research is part of a larger project aimed at discerning subsistence patterns and environmental change in the region. Following the Younger Dryas, as the Fennoscandian ice sheet began to melt, Denmark experienced isostatic rebound, which contributed to the complex sea level history in the region. Between ice melt and isostatic rebound, the Jutland peninsula experienced many transgression and regression events. Connections to surrounding seas have shifted throughout time, with most attention focused on the western connection of the Limfjord with the North Sea, which has experienced numerous closures and subsequent re-openings throughout the Holocene. Furthermore, the Limfjord-North Sea connection has been the focal point of research because of the west to east water flow in the system, and the present day higher salinity in the west compared to the east. Little to no consideration has been paid to the influence of the Kattegat and Baltic on the Limfjord until now. A 10m sediment core was taken from Sebbersund (near Nibe, Limfjord), along the connection between the Limfjord and the Kattegat in the east to understand how the eastern part of the system has changed and differed from changes observed in the west. The Sebbersund sequence spans a majority of the Holocene, from 9600 cal BP to 1030 cal BP, determined via radiocarbon dating of terrestrial macrofossils and bulk sediment. Over this time period palaeoenvironmental conditions were reconstructed through the use of geochemical analyses (δ13C, δ15N, C:N), physical sediment analyses, dinoflagellate cyst abundances and molluscan analyses. Apart from two instances of low salinity, one at the top and one at the bottom of the core, the sequence has a strong marine signal for a majority of the Holocene. Radiocarbon dating of bulk sediment samples showed the presence of old carbon in the system, creating an age offset between 1,300 ± 200 and 2,800 ± 200 calibrated 14C years compared to the age-depth curve based on the terrestrial macrofossils. This finding, along with the strong marine influence in the system, discerned through geochemical data, dinoflagellate cyst and mollusc counts, is important for obtaining accurate radiocarbon ages in the region and stresses the importance of understanding both the marine and freshwater reservoir effects. The marine dominance in the eastern Limfjord differs from the west, which is characterized by a number of freshwater events when the North Sea connection was closed off during the Holocene. The eastern connection was open to the Kattegat throughout a large portion of the Holocene, with influx of open ocean water entering the system during periods of higher sea level.

  18. A Multi-Proxy Analysis of two Loess-Paleosol Sequences in the Northern Harz Foreland

    Science.gov (United States)

    Krauss, Lydia; Zens, Joerg; Zeeden, Christian; Schulte, Philipp; Eckmeier, Eileen; Lehmkuhl, Frank

    2016-04-01

    Within the second phase of the "Collaborative Research Centre 806 (CRC806) - Our Way to Europe - Culture-Environment Interaction and Human Mobility in the Late Quaternary" two loess-paleosol sections in the northern Harz foreland are being investigated. The region is part of the Northern European loess belt. The northern edge of the loess distribution is characterized by an interlocking of Weichselian silt and sand sized aeolian sediments. To the south the Northern European loess belt is limited by the central German uplands (Mittelgebirge). Here the continuous loess cover disperses into separated loess basins. In comparison to relatively long, continuous and intensively studied sections, e.g. along the Rhine river, investigations on loess-paleosol sequences in the northern Harz foreland have been sparse so far. In 2006 REINECKE created an overview of Pleistocene landscape developments by investigating terrace sequences and loess sections in this area. Due to improvements of research methods over the last ten years, the two loess-paleosol sequences Hecklingen and Zilly are being reinvestigated. Aiming towards a better understanding of the paleoenvironmental conditions during the Weichselian in an area close to the Scandinavian ice sheet, results from grain size, geochemical (XRF, CNS) and color measurements are combined. The results show an increased input of aeolian material during the last glacial maximum and the last cover loess period, supporting the theory of dryer and colder conditions during this time frame. Further, we can see a stronger short distant input within the recent soil and during the last glacial maximum in both profiles. In Hecklingen this is also observed within the MIS 3 soil material. Since soil material dating to the MIS 3 is present, we can assume that surface processes where less intrusive during the MIS 3 and 2 as in e.g. the Lower Rhine Embayment. REINECKE, V. (2006): Untersuchungen zur mittel- und jungpleistozänen Reliefentwicklung und Morphodynamik im nördlichen Harzvorland. Aachen (= Aachener Geographische Arbeiten 43).

  19. Reconstructing Asian faunal introductions to eastern Africa from multi-proxy biomolecular and archaeological datasets.

    Directory of Open Access Journals (Sweden)

    Mary E Prendergast

    Full Text Available Human-mediated biological exchange has had global social and ecological impacts. In sub-Saharan Africa, several domestic and commensal animals were introduced from Asia in the pre-modern period; however, the timing and nature of these introductions remain contentious. One model supports introduction to the eastern African coast after the mid-first millennium CE, while another posits introduction dating back to 3000 BCE. These distinct scenarios have implications for understanding the emergence of long-distance maritime connectivity, and the ecological and economic impacts of introduced species. Resolution of this longstanding debate requires new efforts, given the lack of well-dated fauna from high-precision excavations, and ambiguous osteomorphological identifications. We analysed faunal remains from 22 eastern African sites spanning a wide geographic and chronological range, and applied biomolecular techniques to confirm identifications of two Asian taxa: domestic chicken (Gallus gallus and black rat (Rattus rattus. Our approach included ancient DNA (aDNA analysis aided by BLAST-based bioinformatics, Zooarchaeology by Mass Spectrometry (ZooMS collagen fingerprinting, and direct AMS (accelerator mass spectrometry radiocarbon dating. Our results support a late, mid-first millennium CE introduction of these species. We discuss the implications of our findings for models of biological exchange, and emphasize the applicability of our approach to tropical areas with poor bone preservation.

  20. Reconstructing Asian faunal introductions to eastern Africa from multi-proxy biomolecular and archaeological datasets.

    Science.gov (United States)

    Prendergast, Mary E; Buckley, Michael; Crowther, Alison; Frantz, Laurent; Eager, Heidi; Lebrasseur, Ophélie; Hutterer, Rainer; Hulme-Beaman, Ardern; Van Neer, Wim; Douka, Katerina; Veall, Margaret-Ashley; Quintana Morales, Eréndira M; Schuenemann, Verena J; Reiter, Ella; Allen, Richard; Dimopoulos, Evangelos A; Helm, Richard M; Shipton, Ceri; Mwebi, Ogeto; Denys, Christiane; Horton, Mark; Wynne-Jones, Stephanie; Fleisher, Jeffrey; Radimilahy, Chantal; Wright, Henry; Searle, Jeremy B; Krause, Johannes; Larson, Greger; Boivin, Nicole L

    2017-01-01

    Human-mediated biological exchange has had global social and ecological impacts. In sub-Saharan Africa, several domestic and commensal animals were introduced from Asia in the pre-modern period; however, the timing and nature of these introductions remain contentious. One model supports introduction to the eastern African coast after the mid-first millennium CE, while another posits introduction dating back to 3000 BCE. These distinct scenarios have implications for understanding the emergence of long-distance maritime connectivity, and the ecological and economic impacts of introduced species. Resolution of this longstanding debate requires new efforts, given the lack of well-dated fauna from high-precision excavations, and ambiguous osteomorphological identifications. We analysed faunal remains from 22 eastern African sites spanning a wide geographic and chronological range, and applied biomolecular techniques to confirm identifications of two Asian taxa: domestic chicken (Gallus gallus) and black rat (Rattus rattus). Our approach included ancient DNA (aDNA) analysis aided by BLAST-based bioinformatics, Zooarchaeology by Mass Spectrometry (ZooMS) collagen fingerprinting, and direct AMS (accelerator mass spectrometry) radiocarbon dating. Our results support a late, mid-first millennium CE introduction of these species. We discuss the implications of our findings for models of biological exchange, and emphasize the applicability of our approach to tropical areas with poor bone preservation.

  1. Proxy and patient reports of health-related quality of life in a national cancer survey.

    Science.gov (United States)

    Roydhouse, Jessica K; Gutman, Roee; Keating, Nancy L; Mor, Vincent; Wilson, Ira B

    2018-01-05

    Proxy respondents are frequently used in surveys, including those assessing health-related quality of life (HRQOL). In cancer, most research involving proxies has been undertaken with paired proxy-patient populations, where proxy responses are compared to patient responses for the same individual. In these populations, proxy-patient differences are small and suggest proxy underestimation of patient HRQOL. In practice, however, proxy responses will only be used when patient responses are not available. The difference between proxy and patient reports of patient HRQOL where patients are not able to report for themselves in cancer is not known. The objective of this study was to evaluate the difference between patient and proxy reports of patient HRQOL in a large national cancer survey, and determine if this difference could be mitigated by adjusting for clinical and sociodemographic information about patients. Data were from the Cancer Care Outcomes Research and Surveillance (CanCORS) study. Patients or their proxies were recruited within 3-6 months of diagnosis with lung or colorectal cancer. HRQOL was measured using the SF-12 mental and physical composite scales. Differences of ½ SD (=5 points) were considered clinically significant. The primary independent variable was proxy status. Linear regression models were used to adjust for patient sociodemographic and clinical covariates, including cancer stage, patient age and education, and patient co-morbidities. Of 6471 respondents, 1011 (16%) were proxies. Before adjustment, average proxy-reported scores were lower for both physical (-6.7 points, 95% CI -7.4 to -5.9) and mental (-6 points, 95% CI -6.7 to -5.2) health. Proxy-reported scores remained lower after adjustment (physical: -5.8 points, -6.6 to -5; mental: -5.8 points, -6.6 to 5). Proxy-patient score differences remained clinically and statistically significant, even after adjustment for sociodemographic and clinical variables. Proxy-reported outcome scores

  2. 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

  3. Pyrite as a proxy for the identification of former coastal lagoons in semiarid NE Brazil

    Science.gov (United States)

    Ferreira, Tiago O.; Nóbrega, Gabriel N.; Albuquerque, Antonia G. B. M.; Sartor, Lucas R.; Gomes, Irlene S.; Artur, Adriana G.; Otero, Xosé L.

    2015-10-01

    This work aimed to test the suitability of pyrite (FeS2) as a proxy for reconstructing past marine environmental conditions along the semiarid coast of Brazil. Morphological description combined with physicochemical analyses including Fe partitioning were conducted for soil depth profiles (30 and 60 cm depths) at three sites in two contrasting lagoons of the state of Ceará: a suspected former lagoon that would have been transformed into a freshwater "lake" at a site vegetated by Juncus effusus (site P1), and another lagoon with connection to the sea at sites vegetated by J. effusus (site P2) or Portulaca oleracea (site P3). Soil samples were collected in September 2010. Site P3 had more reducing conditions, reaching Eh values of -132 mV in the surface layer (0-10 cm), whereas minimum values for the P1 and P2 sites were +219 and +85 mV, respectively. Lower pyritic Fe values were found at site P1, with a degree of pyritization (DOP) ranging from 10 to 13%. At sites P2 and P3, DOP ranged from 9 to 67% and from 55 to 72%, respectively. These results are consistent with an interruption of tidal channels by eolian dune migration inducing strong changes in the hydrodynamics and physicochemical characteristics (lower salinity, oxidizing conditions) of these sites, causing the dieback of suspected former mangroves and a succession to freshwater marshes with an intermediate salt marsh stage. Together with other physicochemical signatures, pyrite can evidently serve as a useful proxy in tracking environmental changes in such ecotones, with implications for coastal management.

  4. SOLAR CYCLE PROPAGATION, MEMORY, AND PREDICTION: INSIGHTS FROM A CENTURY OF MAGNETIC PROXIES

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Jaramillo, Andres; DeLuca, Edward E. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Dasi-Espuig, Maria [Max-Planck-Institut fuer Sonnensystemforschung, D-37191 Katlenburg-Lindau (Germany); Balmaceda, Laura A., E-mail: amunoz@cfa.harvard.edu, E-mail: edeluca@cfa.harvard.edu, E-mail: dasi@mps.mpg.de, E-mail: lbalmaceda@icate-conicet.gob.ar [Institute for Astronomical, Terrestrial and Space Sciences (ICATE-CONICET), San Juan (Argentina)

    2013-04-20

    The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and Earth's upper atmosphere (commonly referred to as space weather). These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. A major contributor to the disagreement is the lack of direct long-term databases covering different components of the solar magnetic field (toroidal versus poloidal). Here, we use sunspot area and polar faculae measurements spanning a full century (as our toroidal and poloidal field proxies) to study solar cycle propagation, memory, and prediction. Our results substantiate predictions based on the polar magnetic fields, whereas we find sunspot area to be uncorrelated with cycle amplitude unless multiplied by area-weighted average tilt. This suggests that the joint assimilation of tilt and sunspot area is a better choice (with aims to cycle prediction) than sunspot area alone, and adds to the evidence in favor of active region emergence and decay as the main mechanism of poloidal field generation (i.e., the Babcock-Leighton mechanism). Finally, by looking at the correlation between our poloidal and toroidal proxies across multiple cycles, we find solar cycle memory to be limited to only one cycle.

  5. 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.

  6. 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.

  7. Proxy studies of energy transfer to the magnetosphere

    International Nuclear Information System (INIS)

    Scurry, L.; Russell, C.T.

    1991-01-01

    The transfer of energy into the magnetosphere is studied using as proxy the Am geomagnetic index and multilinear regressions and correlations with solar wind data. In particular, the response of Am to the reconnection mechanism is examined in relation to the orientation of the interplanetary magnetic field as well as the upstream plasma parameters. A functional dependence of Am on clock angle, the orientation of the IMF in the plane perpendicular to the flow, is derived after first correcting the index for nonreconnection effects due to dynamic pressure and velocity. An examination of the effect of upstream magnetosonic Mach number shows the reconnection mechanism to become less efficient at high Mach numbers. The reconnection mechanism is shown to be slightly enhanced by higher dynamic pressures

  8. Towards a new paleotemperature proxy from reef coral occurrences.

    Science.gov (United States)

    Lauchstedt, Andreas; Pandolfi, John M; Kiessling, Wolfgang

    2017-09-05

    Global mean temperature is thought to have exceeded that of today during the last interglacial episode (LIG, ~ 125,000 yrs b.p.) but robust paleoclimate data are still rare in low latitudes. Occurrence data of tropical reef corals may provide new proxies of low latitude sea-surface temperatures. Using modern reef coral distributions we developed a geographically explicit model of sea surface temperatures. Applying this model to coral occurrence data of the LIG provides a latitudinal U-shaped pattern of temperature anomalies with cooler than modern temperatures around the equator and warmer subtropical climes. Our results agree with previously published estimates of LIG temperatures and suggest a poleward broadening of the habitable zone for reef corals during the LIG.

  9. 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.

  10. Differences between Proxy and Patient Assessments of Cancer Care Experiences and Quality Ratings.

    Science.gov (United States)

    Roydhouse, Jessica K; Gutman, Roee; Keating, Nancy L; Mor, Vincent; Wilson, Ira B

    2018-04-01

    To assess the impact of proxy survey responses on cancer care experience reports and quality ratings. Secondary analysis of data from Cancer Care Outcomes Research and Surveillance (CanCORS). Recruitment occurred from 2003 to 2005. The study was a cross-sectional observational study. The respondents were patients with incident colorectal or lung cancer or their proxies. Analyses used linear regression models with an independent variable for proxy versus patient responses as well as study site and clinical covariates. The outcomes were experiences with medical care, nursing care, care coordination, and care quality rating. Multiple imputation was used for missing data. Among 6,471 respondents, 1,011 (16 percent) were proxies. The proportion of proxy respondents varied from 6 percent to 28 percent across study sites. Adjusted proxy scores were modestly higher for medical care experiences (+1.28 points [95 percent CI:+ 0.05 to +2.51]), but lower for nursing care (-2.81 [95 percent CI: -4.11 to -1.50]) and care coordination experiences (-2.98 [95 percent CI: -4.15 to -1.81]). There were no significant differences between adjusted patient and proxy ratings of quality. Proxy responses have small but statistically significant differences from patient responses. However, if ratings of care are used for financial incentives, such differences could be exaggerated across practices or areas if proxy use varies. © Health Research and Educational Trust.

  11. IPv6 Addressing Proxy: Mapping Native Addressing from Legacy Technologies and Devices to the Internet of Things (IPv6

    Directory of Open Access Journals (Sweden)

    Peter Kirstein

    2013-05-01

    Full Text Available Sensors utilize a large number of heterogeneous technologies for a varied set of application environments. The sheer number of devices involved requires that this Internet be the Future Internet, with a core network based on IPv6 and a higher scalability in order to be able to address all the devices, sensors and things located around us. This capability to connect through IPv6 devices, sensors and things is what is defining the so-called Internet of Things (IoT. IPv6 provides addressing space to reach this ubiquitous set of sensors, but legacy technologies, such as X10, European Installation Bus (EIB, Controller Area Network (CAN and radio frequency ID (RFID from the industrial, home automation and logistic application areas, do not support the IPv6 protocol. For that reason, a technique must be devised to map the sensor and identification technologies to IPv6, thus allowing homogeneous access via IPv6 features in the context of the IoT. This paper proposes a mapping between the native addressing of each technology and an IPv6 address following a set of rules that are discussed and proposed in this work. Specifically, the paper presents a technology-dependent IPv6 addressing proxy, which maps each device to the different subnetworks built under the IPv6 prefix addresses provided by the internet service provider for each home, building or user. The IPv6 addressing proxy offers a common addressing environment based on IPv6 for all the devices, regardless of the device technology. Thereby, this offers a scalable and homogeneous solution to interact with devices that do not support IPv6 addressing. The IPv6 addressing proxy has been implemented in a multi-protocol Sensors 2013, 13 6688 card and evaluated successfully its performance, scalability and interoperability through a protocol built over IPv6.

  12. IPv6 Addressing Proxy: Mapping Native Addressing from Legacy Technologies and Devices to the Internet of Things (IPv6)

    Science.gov (United States)

    Jara, Antonio J.; Moreno-Sanchez, Pedro; Skarmeta, Antonio F.; Varakliotis, Socrates; Kirstein, Peter

    2013-01-01

    Sensors utilize a large number of heterogeneous technologies for a varied set of application environments. The sheer number of devices involved requires that this Internet be the Future Internet, with a core network based on IPv6 and a higher scalability in order to be able to address all the devices, sensors and things located around us. This capability to connect through IPv6 devices, sensors and things is what is defining the so-called Internet of Things (IoT). IPv6 provides addressing space to reach this ubiquitous set of sensors, but legacy technologies, such as X10, European Installation Bus (EIB), Controller Area Network (CAN) and radio frequency ID (RFID) from the industrial, home automation and logistic application areas, do not support the IPv6 protocol. For that reason, a technique must be devised to map the sensor and identification technologies to IPv6, thus allowing homogeneous access via IPv6 features in the context of the IoT. This paper proposes a mapping between the native addressing of each technology and an IPv6 address following a set of rules that are discussed and proposed in this work. Specifically, the paper presents a technology-dependent IPv6 addressing proxy, which maps each device to the different subnetworks built under the IPv6 prefix addresses provided by the internet service provider for each home, building or user. The IPv6 addressing proxy offers a common addressing environment based on IPv6 for all the devices, regardless of the device technology. Thereby, this offers a scalable and homogeneous solution to interact with devices that do not support IPv6 addressing. The IPv6 addressing proxy has been implemented in a multi-protocol card and evaluated successfully its performance, scalability and interoperability through a protocol built over IPv6. PMID:23686145

  13. IPv6 addressing proxy: mapping native addressing from legacy technologies and devices to the Internet of Things (IPv6).

    Science.gov (United States)

    Jara, Antonio J; Moreno-Sanchez, Pedro; Skarmeta, Antonio F; Varakliotis, Socrates; Kirstein, Peter

    2013-05-17

    Sensors utilize a large number of heterogeneous technologies for a varied set of application environments. The sheer number of devices involved requires that this Internet be the Future Internet, with a core network based on IPv6 and a higher scalability in order to be able to address all the devices, sensors and things located around us. This capability to connect through IPv6 devices, sensors and things is what is defining the so-called Internet of Things (IoT). IPv6 provides addressing space to reach this ubiquitous set of sensors, but legacy technologies, such as X10, European Installation Bus (EIB), Controller Area Network (CAN) and radio frequency ID (RFID) from the industrial, home automation and logistic application areas, do not support the IPv6 protocol. For that reason, a technique must be devised to map the sensor and identification technologies to IPv6, thus allowing homogeneous access via IPv6 features in the context of the IoT. This paper proposes a mapping between the native addressing of each technology and an IPv6 address following a set of rules that are discussed and proposed in this work. Specifically, the paper presents a technology-dependent IPv6 addressing proxy, which maps each device to the different subnetworks built under the IPv6 prefix addresses provided by the internet service provider for each home, building or user. The IPv6 addressing proxy offers a common addressing environment based on IPv6 for all the devices, regardless of the device technology. Thereby, this offers a scalable and homogeneous solution to interact with devices that do not support IPv6 addressing. The IPv6 addressing proxy has been implemented in a multi-protocol Sensors 2013, 13 6688 card and evaluated successfully its performance, scalability and interoperability through a protocol built over IPv6.

  14. 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

  15. Detecting oscillatory patterns and time lags from proxy records with non-uniform sampling: Some pitfalls and possible solutions

    Science.gov (United States)

    Donner, Reik

    2013-04-01

    Time series analysis offers a rich toolbox for deciphering information from high-resolution geological and geomorphological archives and linking the thus obtained results to distinct climate and environmental processes. Specifically, on various time-scales from inter-annual to multi-millenial, underlying driving forces exhibit more or less periodic oscillations, the detection of which in proxy records often allows linking them to specific mechanisms by which the corresponding drivers may have affected the archive under study. A persistent problem in geomorphology is that available records do not present a clear signal of the variability of environmental conditions, but exhibit considerable uncertainties of both the measured proxy variables and the associated age model. Particularly, time-scale uncertainty as well as the heterogeneity of sampling in the time domain are source of severe conceptual problems that may lead to false conclusions about the presence or absence of oscillatory patterns and their mutual phasing in different archives. In my presentation, I will discuss how one can cope with non-uniformly sampled proxy records to detect and quantify oscillatory patterns in one or more data sets. For this purpose, correlation analysis is reformulated using kernel estimates which are found superior to classical estimators based on interpolation or Fourier transform techniques. In order to characterize non-stationary or noisy periodicities and their relative phasing between different records, an extension of continuous wavelet transform is utilized. The performance of both methods is illustrated for different case studies. An extension to explicitly considering time-scale uncertainties by means of Bayesian techniques is briefly outlined.

  16. An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120-800 ka

    Science.gov (United States)

    Bazin, L.; Landais, A.; Lemieux-Dudon, B.; Toyé Mahamadou Kele, H.; Veres, D.; Parrenin, F.; Martinerie, P.; Ritz, C.; Capron, E.; Lipenkov, V.; Loutre, M.-F.; Raynaud, D.; Vinther, B.; Svensson, A.; Rasmussen, S. O.; Severi, M.; Blunier, T.; Leuenberger, M.; Fischer, H.; Masson-Delmotte, V.; Chappellaz, J.; Wolff, E.

    2013-08-01

    An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120-800 ka. In this framework, new measurements of δ18Oatm over Marine Isotope Stage (MIS) 11-12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content) has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

  17. An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012: 120–800 ka

    Directory of Open Access Journals (Sweden)

    L. Bazin

    2013-08-01

    Full Text Available An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice, combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present (Lemieux-Dudon et al., 2010. In this paper, together with the companion paper of Veres et al. (2013, we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012 chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka. In this framework, new measurements of δ18Oatm over Marine Isotope Stage (MIS 11–12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

  18. Geochemistry of coral from Papua New Guinea as a proxy for ENSO ocean-atmosphere interactions in the Pacific Warm Pool

    Science.gov (United States)

    Ayliffe, Linda K.; Bird, Michael I.; Gagan, Michael K.; Isdale, Peter J.; Scott-Gagan, Heather; Parker, Bruce; Griffin, David; Nongkas, Michael; McCulloch, Malcolm T.

    2004-12-01

    A Porites sp. coral growing offshore from the Sepik and Ramu Rivers in equatorial northern Papua New Guinea has yielded an accurate 20-year history (1977-1996) of sea surface temperature (SST), river discharge, and wind-induced mixing of the upper water column. Depressions in average SSTs of about 0.5-1.0 °C (indicated by coral Sr/Ca) and markedly diminished freshwater runoff to the coastal ocean (indicated by coral δ18O, δ13C and UV fluorescence) are evident during the El Niño - Southern Oscillation (ENSO) events of 1982-1983, 1987 and 1991-1993. The perturbations recorded by the coral are in good agreement with changes in instrumental SST and river discharge/precipitation records, which are known to be diagnostic of the response of the Pacific Warm Pool ocean-atmosphere system to El Niño. Consideration of coastal ocean dynamics indicates that the establishment of northwest monsoon winds promotes mixing of near-surface waters to greater depths in the first quarter of most years, making the coral record sensitive to changes in the Asian-Australian monsoon cycle. Sudden cooling of SSTs by ˜1°C following westerly wind episodes, as indicated by the coral Sr/Ca, is consistent with greater mixing in the upper water column at these times. Furthermore, the coral UV fluorescence and oxygen isotope data indicate minimal contribution of river runoff to surface ocean waters at the beginning of most years, during the time of maximum discharge. This abrupt shift in flood-plume behaviour appears to reflect the duration and magnitude of northwest monsoon winds, which tend to disperse flood plume waters to a greater extent in the water column when wind-mixing is enhanced. Our results suggest that a multi-proxy geochemical approach to the production of long coral records should provide comprehensive reconstructions of tropical paleoclimate processes operating on interannual timescales.

  19. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie N.

    2017-01-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates corals that passed this quality control step, the Sr/Ca-SST proxy performed well in estimating mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.Plain Language SummaryCoral skeletons are used to decipher past environmental conditions in the ocean because they live for centuries and produce annual growth bands much like tree rings. Along with measuring coral growth rates in the past, coral skeletons can be chemically sampled to get even more detailed information, like past seawater temperatures. In this study we tested the validity of the strontium-to-calcium (Sr/Ca) temperature proxy in the Massive Starlet Coral (Siderastrea siderea) by sampling 39 corals that were grown in the ocean right next to instruments recording underwater temperature. We found that, as long as corals with very slow growth

  20. Evaluation of proxy tests for SFSN: evidence for mixed small and large fiber dysfunction.

    Directory of Open Access Journals (Sweden)

    Hamid Ebadi

    Full Text Available BACKGROUND: Though intra-epidermal nerve fiber density (IENFD is considered the gold standard for diagnosis of small fiber sensory neuropathy (SFSN, we aimed to determine if novel threshold values derived from standard tests of small or large fiber function could serve as diagnostic alternatives. METHODS: Seventy-four consecutive patients with painful polyneuropathy and normal nerve conduction studies (NCS were defined as SFSN cases or controls by distal IENFD <5.4 and ≥5.4 fibers/mm, respectively. Diagnostic performance of small fiber [cooling (CDT and heat perception (HP thresholds, axon reflex-mediated neurogenic vasodilatation] and large fiber function tests [vibration perception thresholds (VPT and sural nerve conduction parameters] were determined by receiver operating-characteristic (ROC curve analyses. RESULTS: The 26(35% SFSN cases had mean IENFD 3.3±1.7 fibers/mm and the 48(65% controls 9.9±2.9 fibers/mm. Male gender (p = 0.02 and older age (p = 0.02 were associated with SFSN cases compared to controls. VPT were higher and CDT lower in SFSN cases, but the largest magnitude of differences was observed for sural nerve amplitude. It had the greatest area under the ROC curve (0.75 compared to all other tests (p<0.001 for all comparisons and the optimal threshold value of ≤12 µV defined SFSN cases with 80% sensitivity and 72% specificity. CONCLUSION: In patients presenting with polyneuropathy manifestations and normal NCS, though small fiber function tests were intuitively considered the best alternative measures to predict reduced IENFD, their diagnostic performance was poor. Instead, novel threshold values within the normal range for large fiber tests should be considered as an alternative strategy to select subjects for skin biopsy in diagnostic protocols for SFSN.

  1. Distribution of biologic, anthropogenic, and volcanic constituents as a proxy for sediment transport in the San Francisco Bay Coastal System

    Science.gov (United States)

    McGann, Mary; Erikson, Li H.; Wan, Elmira; Powell, Charles; Maddocks, Rosalie F.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    Although conventional sediment parameters (mean grain size, sorting, and skewness) and provenance have typically been used to infer sediment transport pathways, most freshwater, brackish, and marine environments are also characterized by abundant sediment constituents of biological, and possibly anthropogenic and volcanic, origin that can provide additional insight into local sedimentary processes. The biota will be spatially distributed according to its response to environmental parameters such as water temperature, salinity, dissolved oxygen, organic carbon content, grain size, and intensity of currents and tidal flow, whereas the presence of anthropogenic and volcanic constituents will reflect proximity to source areas and whether they are fluvially- or aerially-transported. Because each of these constituents have a unique environmental signature, they are a more precise proxy for that source area than the conventional sedimentary process indicators. This San Francisco Bay Coastal System study demonstrates that by applying a multi-proxy approach, the primary sites of sediment transport can be identified. Many of these sites are far from where the constituents originated, showing that sediment transport is widespread in the region. Although not often used, identifying and interpreting the distribution of naturally-occurring and allochthonous biologic, anthropogenic, and volcanic sediment constituents is a powerful tool to aid in the investigation of sediment transport pathways in other coastal systems.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Goal specificity: a proxy measure for improvements in environmental outcomes in collaborative governance.

    Science.gov (United States)

    Biddle, Jennifer C; Koontz, Tomas M

    2014-12-01

    Collaborative governance critics continually call for evidence to support its prevalent use. As is often the case in environmental policy, environmental outcomes occur at a rate incompatible with political agendas. In addition, a multitude of possibly confounding variables makes it difficult to correlate collaborative governance processes with environmental outcomes. The findings of this study offer empirical evidence that collaborative processes have a measurable, beneficial effect on environmental outcomes. Through the use of a unique paired-waterbody design, our dataset reduced the potential for confounding variables to impact our environmental outcome measurements. The results of a path analysis indicate that the output of setting specific pollutant reduction goals is significantly related to watershed partnerships' level of attainment of their environmental improvement goals. The action of setting specific goals (e.g. percentage of load reductions in pollutant levels) is fostered by sustained participation from partnership members throughout the lifecycle of the collaborative. In addition, this study demonstrates the utility of logic modeling for environmental planning and management, and suggests that the process of setting specific pollutant reduction goals is a useful proxy measure for reporting progress towards improvements in environmental outcomes when long-term environmental data are not available. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Potential barriers to the application of multi-factor portfolio analysis in public hospitals: evidence from a pilot study in the Netherlands.

    Science.gov (United States)

    Pavlova, Milena; Tsiachristas, Apostolos; Vermaeten, Gerhard; Groot, Wim

    2009-01-01

    Portfolio analysis is a business management tool that can assist health care managers to develop new organizational strategies. The application of portfolio analysis to US hospital settings has been frequently reported. In Europe however, the application of this technique has received little attention, especially concerning public hospitals. Therefore, this paper examines the peculiarities of portfolio analysis and its applicability to the strategic management of European public hospitals. The analysis is based on a pilot application of a multi-factor portfolio analysis in a Dutch university hospital. The nature of portfolio analysis and the steps in a multi-factor portfolio analysis are reviewed along with the characteristics of the research setting. Based on these data, a multi-factor portfolio model is developed and operationalized. The portfolio model is applied in a pilot investigation to analyze the market attractiveness and hospital strengths with regard to the provision of three orthopedic services: knee surgery, hip surgery, and arthroscopy. The pilot portfolio analysis is discussed to draw conclusions about potential barriers to the overall adoption of portfolio analysis in the management of a public hospital. Copyright (c) 2008 John Wiley & Sons, Ltd.

  5. Holocene seasonal variability inferred from multiple proxy records from Crevice Lake, Yellowstone National Park, USA

    Science.gov (United States)

    Whitlock, Cathy; Dean, Walter E.; Fritz, Sherilyn C.; Stevens, Lora R.; Stone, Jeffery R.; Power, Mitchell J.; Rosenbaum, Joseph R.; Pierce, Kenneth L.; Bracht-Flyr, Brandi B.

    2012-01-01

    the Roman Warm Period (~ 2000 cal yr BP) and Medieval Climate Anomaly (1200–800 cal yr BP). Long springs and mild summers occurred during the Little Ice Age, and these conditions persist to the present. Although the proxy data indicate effectively wet summer conditions in the early Holocene and drier conditions in the middle and late Holocene, none point specifically to changes in summer precipitation as the cause. Instead, summer conditions were governed by multi-seasonal controls on effective moisture that operated over multiple time scales.

  6. Evidence for Isostatic Emergence and Holocene Environmental Change Recorded in Chironomid Assemblages and Sediment Composition of Coastal Lake T1 in SW Greenland

    Science.gov (United States)

    Berman, K.; Axford, Y.; Lasher, G. E.

    2017-12-01

    Multi-proxy analysis of a coastal lake in southwest Greenland near Nuuk provides evidence for regional environmental changes, including the timing of isostatic rebound and the temperature history of the area. T1 (informal name) is a small lake 50 km south of Nuuk, at 17.5 m elevation and currently isolated from glacial meltwater drainage. The lake's sediment record begins approximately 9500 cal years BP, when the site was submerged beneath sea level due to glacial isostatic depression following the Last Glacial Maximum. The record captures the transition of the environment from a submerged, glacially-influenced marine site to a non-glacially fed (and initially meromictic) freshwater lake 8600 cal years BP. Magnetic susceptibility, a proxy for sediment minerogenic content, decreased rapidly from 9500 to 8600 years BP, before abruptly stabilizing and remaining relatively low and steady for the rest of the record. The transition to a lacustrine environment was characterized by a rapid and relatively simultaneous increase in primary productivity (inferred from biogenic silica concentrations) and shift towards terrestrial versus marine sources of organic matter (inferred from carbon:nitrogen ratios and nitrogen isotopes) between 8700 and 8400 years BP. Together, these proxies and the presence of marine shells below the transition provide robust evidence for the transition from a marine environment to a freshwater lake in response to regional postglacial isostatic rebound. Within the Holocene, measures of bulk sediment composition (e.g., biogenic silica, loss-on-ignition and magnetic susceptibility) are relatively stable. Chironomid (Insecta: Diptera: Chironomidae) assemblages, which in some environments are quantitative proxies for summer temperature changes, show species-level shifts within the Holocene that will be interpreted in this presentation alongside indicators of landscape change including carbon:nitrogen ratios, bulk sediment spectral reflectance and bulk

  7. 47 CFR 51.513 - Proxies for forward-looking economic cost.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Proxies for forward-looking economic cost. 51... 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...

  8. 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

    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...

  9. Testing the timing of radiocarbon-dated events between proxy archives

    NARCIS (Netherlands)

    Christen, J. A.; Mauquoy, D.; van der Plicht, J.; Bennett, K. D.; Blaauw, Maarten

    For interpreting past changes on a regional or global scale, the timings of proxy-inferred events are usually aligned with data from other locations. However, too often chronological uncertainties are ignored in proxy diagrams and multisite comparisons, making it possible for researchers to fall

  10. Proxy support for service discovery using mDNS/DNS-SD in low power networks

    NARCIS (Netherlands)

    Stolikj, M.; Verhoeven, R.; Cuijpers, P.J.L.; Lukkien, J.J.

    2014-01-01

    We present a solution for service discovery of resource constrained devices based on mDNS/DNS-SD. We extend the mDNS/DNS-SD service discovery protocol with support for proxy servers. Proxy servers temporarily store information about services offered on resource constrained devices and respond on

  11. Mixtures of Gaussians for uncertainty description in bivariate latent heat flux proxies

    NARCIS (Netherlands)

    Wójcik, R.; Troch, P.A.A.; Stricker, J.N.M.; Torfs, P.J.J.F.

    2006-01-01

    This paper proposes a new probabilistic approach for describing uncertainty in the ensembles of latent heat flux proxies. The proxies are obtained from hourly Bowen ratio and satellite-derived measurements, respectively, at several locations in the southern Great Plains region in the United States.

  12. Architecture of a bi-directional Bluetooth-UPnP proxy

    NARCIS (Netherlands)

    Delphinanto, A.; Lukkien, J.J.; Koonen, A.M.J.; Hartog, F.T.H. den; Madureira, A.J.P.S.; Niemegeers, I.G.M.M.; Selgert, F.

    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 UPnP devices and services to be discovered

  13. 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

  14. Limiting exercise options: depending on a proxy may inhibit exercise self-management.

    Science.gov (United States)

    Shields, Christopher A; Brawley, Lawrence R

    2007-07-01

    We examined the influence of proxy-assistance on exercisers' social cognitions and behavior. Fifty-six fitness class participants reported preference for proxy-assistance and reacted to exercising in different contexts. A 2 (proxy-led vs self-managed exercise context) by 2 (preferred assistance) MANOVA revealed significant assistance by context interactions for self-regulatory efficacy (SRE) and difficulty. Regarding self-managed exercise, high-assistance individuals expressed lower SRE and higher difficulty. Chi-square analysis revealed that significantly fewer high-assistance participants chose self-managed exercise. A one-way MANOVA on preferred assistance indicated that high-assistance participants were less confident, satisfied and perceived their self-managed exercise as more difficult. Results support Bandura's theorizing that use of a proxy can limit SRE of those preferring the proxy's control of their behavior.

  15. Validation and application of a death proxy in adult cancer patients.

    Science.gov (United States)

    Mealing, Nicole M; Dobbins, Timothy A; Pearson, Sallie-Anne

    2012-07-01

    PURPOSE: Fact of death is not always available on data sets used for pharmacoepidemiological research. Proxies may be an appropriate substitute in the absence of death data. The purposes of this study were to validate a proxy for death in adult cancer patients and to assess its performance when estimating survival in two cohorts of cancer patients. METHODS: We evaluated 30-, 60-, 90- and 180-day proxies overall and by cancer type using data from 12 394 Australian veterans with lung, colorectal, breast or prostate cancer. The proxy indicated death if the difference between the last dispensing record and the end of the observational period exceeded the proxy cutoff. We then compared actual survival to 90-day proxy estimates in a subset of 4090 veterans with 'full entitlements' for pharmaceutical items and in 3704 Australian women receiving trastuzumab for HER2+ metastatic breast cancer. RESULTS: The 90-day proxy was optimal with an overall sensitivity of 99.3% (95%CI: 98.4-99.7) and a specificity of 97.6% (95%CI: 91.8-99.4). These measures remained high when evaluated by cancer type and spread of disease. The application of the proxy using the most conservative date of death estimate (date of last dispensing) generally underestimated survival, with estimates up to 3 months shorter than survival based on fact of death. CONCLUSIONS: A 90-day death proxy is a robust substitute to identify death in a chronic population when fact of death is not available. The proxy is likely to be valid across a range of chronic diseases as it relies on the presence of 'regular' dispensing records for individual patients. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.

  16. 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.

  17. Magnetic susceptibility: a proxy method of estimating increased pollution

    International Nuclear Information System (INIS)

    Kluciarova, D.; Gregorova, D.; Tunyi, I.

    2004-01-01

    A need for rapid and inexpensive (proxy) methods of outlining areas exposed to increased pollution by atmospheric particulates of industrial origin caused scientists in various fields to use and validate different non-traditional (or non-chemical) techniques. Among them, soil magnetometry seems to be a suitable tool. This method is based on the knowledge that ferrimagnetic particles, namely magnetite, are produced from pyrite during combustion of fossil fuel. Besides the combustion processes, magnetic particles can also originate from road traffic, for example, or can be included in various waste-water outlets. In our study we examine the magnetic susceptibility as a convenient measure of determining the concentration of (ferri) magnetic minerals by rapid and non-destructive means. We used for measure KLY-2 Kappabridge. Concentration of ferrimagnetic minerals in different soils is linked to pollution sources. Higher χ values were observed in soils on the territory in Istebne (47383x10 -6 SI ). The susceptibility anomaly may be caused by particular geological circumstances and can be related to high content of ferromagnetic minerals in the host rocks. Positive correlation of magnetic susceptibility are conditioned by industrial contamination mainly by metal working factories and by traffic. The proposed method can be successfully applied in determining heavy metal pollution of soils on the city territories. (authors)

  18. 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.

  19. 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.

  20. Enhanced Predictive Handover for Fast Proxy Mobile IPv6

    Science.gov (United States)

    Jeon, Seil; Kang, Namhi; Kim, Younghan

    Proxy Mobile IPv6 (PMIPv6) has been proposed in order to overcome the limitations of host-based mobility management in IPv6 networks. However, packet losses during doing handover are still a problem. To solve this issue, several schemes have been developed, and can be classified into two approaches: predictive and reactive handover. Both approaches commonly use bi-directional tunnel between mobile access gateways (MAGs). In predictive schemes especially, mobility support for a mobile node (MN) is triggered by simplified link signal strength. Thereafter, the MN sends handover notification to its serving MAG, and is then able to initiate packet forwarding. Therefore, if the MN moves toward an unexpected MAG that does not have any pre-established tunnel with the serving MAG, it may lead to packet losses. In this paper, we define this problem as Early Packet Forwarding (EPF). As a solution, we propose an enhanced PMIPv6 scheme using two-phase tunnel control based on the IEEE 802.21 Media Independent Handover (MIH).

  1. Is the extremely rare Iberian endemic plant species Castrilanthemum debeauxii (Compositae, Anthemideae) a 'living fossil'? Evidence from a multi-locus species tree reconstruction.

    Science.gov (United States)

    Tomasello, Salvatore; Álvarez, Inés; Vargas, Pablo; Oberprieler, Christoph

    2015-01-01

    The present study provides results of multi-species coalescent species tree analyses of DNA sequences sampled from multiple nuclear and plastid regions to infer the phylogenetic relationships among the members of the subtribe Leucanthemopsidinae (Compositae, Anthemideae), to which besides the annual Castrilanthemum debeauxii (Degen, Hervier & É.Rev.) Vogt & Oberp., one of the rarest flowering plant species of the Iberian Peninsula, two other unispecific genera (Hymenostemma, Prolongoa), and the polyploidy complex of the genus Leucanthemopsis belong. Based on sequence information from two single- to low-copy nuclear regions (C16, D35, characterised by Chapman et al. (2007)), the multi-copy region of the nrDNA internal transcribed spacer regions ITS1 and ITS2, and two intergenic spacer regions of the cpDNA gene trees were reconstructed using Bayesian inference methods. For the reconstruction of a multi-locus species tree we applied three different methods: (a) analysis of concatenated sequences using Bayesian inference (MrBayes), (b) a tree reconciliation approach by minimizing the number of deep coalescences (PhyloNet), and (c) a coalescent-based species-tree method in a Bayesian framework ((∗)BEAST). All three species tree reconstruction methods unequivocally support the close relationship of the subtribe with the hitherto unclassified genus Phalacrocarpum, the sister-group relationship of Castrilanthemum with the three remaining genera of the subtribe, and the further sister-group relationship of the clade of Hymenostemma+Prolongoa with a monophyletic genus Leucanthemopsis. Dating of the (∗)BEAST phylogeny supports the long-lasting (Early Miocene, 15-22Ma) taxonomical independence and the switch from the plesiomorphic perennial to the apomorphic annual life-form assumed for the Castrilanthemum lineage that may have occurred not earlier than in the Pliocene (3Ma) when the establishment of a Mediterranean climate with summer droughts triggered evolution towards

  2. Experimental evidence of the generation of multi-hundred megabar pressures in 0.26 μm wavelength laser experiments

    International Nuclear Information System (INIS)

    Fabro, R.; Faral, B.; Virmont, J.; Pepin, H.; Cottet, F.; Romain, J.P.

    1986-01-01

    A 9 μm thick aluminium foil is accelerated to a velocity of about 160 km/s by a laser of 0.26 μm wavelength and intensity of 10 15 W/cm 2 and collides with an aluminium impact foil. The measurement of the velocity of the induced shock wave in the impact foil, using a step method at the rear of the impact foil, gives pressures in the multi-hundred megabar range. The dynamics and constraints of this shock wave are presented and the effect of X-ray preheating, which can be important at this laser wavelength, is discussed. (author)

  3. Functional Anatomy of Recognition of Chinese Multi-Character Words: Convergent Evidence from Effects of Transposable Nonwords, Lexicality, and Word Frequency.

    Science.gov (United States)

    Lin, Nan; Yu, Xi; Zhao, Ying; Zhang, Mingxia

    2016-01-01

    This fMRI study aimed to identify the neural mechanisms underlying the recognition of Chinese multi-character words by partialling out the confounding effect of reaction time (RT). For this purpose, a special type of nonword-transposable nonword-was created by reversing the character orders of real words. These nonwords were included in a lexical decision task along with regular (non-transposable) nonwords and real words. Through conjunction analysis on the contrasts of transposable nonwords versus regular nonwords and words versus regular nonwords, the confounding effect of RT was eliminated, and the regions involved in word recognition were reliably identified. The word-frequency effect was also examined in emerged regions to further assess their functional roles in word processing. Results showed significant conjunctional effect and positive word-frequency effect in the bilateral inferior parietal lobules and posterior cingulate cortex, whereas only conjunctional effect was found in the anterior cingulate cortex. The roles of these brain regions in recognition of Chinese multi-character words were discussed.

  4. Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+,Er3+ phosphors.

    Science.gov (United States)

    Cho, Youngho; Song, Si Won; Lim, Soo Yeong; Kim, Jae Hun; Park, Chan Ryang; Kim, Hyung Min

    2017-03-08

    Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF 4 :Yb 3+ ,Er 3+ phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.

  5. Testing the fidelity of the Sr/Ca proxy in recording ocean temperature in a western Atlantic coral

    Science.gov (United States)

    Kuffner, I. B.; Roberts, K.; Flannery, J. A.; Richey, J. N.; Morrison, J. M.

    2017-12-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a field-based coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates less than 1.7 mg cm-2 d-1 or LE rates less than 1.7 mm yr-1 returned spuriously high Sr/Ca values, leading to a cold bias in Sr/Ca-based SST estimates. The threshold-type response curves suggest that LE rate can be used as a quality-control indicator during sample and microdrill-path selection when using long cores for SST paleoreconstruction. For our corals that passed this quality control step, the Sr/Ca-SST proxy performed well in estimating mean annual SST across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.

  6. Individuals with high obsessive-compulsive tendencies or undermined confidence rely more on external proxies to access their internal states.

    Science.gov (United States)

    Zhang, Zhongming; Wang, Mengyun; Miao, Xiaocui; Li, Yijuan; Hitchman, Glenn; Yuan, Zhen

    2017-03-01

    The Seeking Proxies for Internal States (SPIS) hypothesis predicts that obsessive-compulsive disorder (OCD) is associated with a deficit in subjective convictions, which may lead to a reliance on external substitutes for the perceptions of an individual's internal states. Two well-designed studies were performed for the present work that adopted a false bio-feedback procedure in a muscle tension task to examine the SPIS hypothesis. The false bio-feedback paradigm was used to investigate our hypothesis. NeXus-10 Mark II hardware and V2011 BioTrace + software (Mind Media B.V., Herten, Netherlands) were utilized to measure the muscle tension of the flexor carpiulnaris muscle, which characterized the target's internal state. In addition, false EMG changes were recorded and displayed on a computer monitor and were considered external proxies. Study 1 demonstrated that the participants with high obsessive-compulsive (OC) tendencies were more affected by the false bio-feedback and exhibited lower confidence in their judgments regarding their muscle tension compared with the participants with low OC tendencies. These findings indicate that subjects with high OC tendencies were more influenced by self-perception effects. In contrast, the subjects in the undermined confidence group in Study 2 were more easily influenced by the false bio-feedback compared with the control group, which suggests that the subjects in the undermined confidence group were more affected by self-perception effects. We did not combine the undermined confidence with OC tendencies or OCD symptoms in our paradigm to investigate their joint effects on self-perception. Our findings provide further evidence that supports the SPIS hypothesis, which indicates that OC tendencies and the confidence in an individual's recognition of internal states appear to have similar effects on the assessment of internal states and reliance on proxies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Developing Evidence for Public Health Policy and Practice: The Implementation of a Knowledge Translation Approach in a Staged, Multi-Methods Study in England, 2007-09

    Science.gov (United States)

    South, Jane; Cattan, Mima

    2014-01-01

    Effective knowledge translation processes are critical for the development of evidence-based public health policy and practice. This paper reports on the design and implementation of an innovative approach to knowledge translation within a mixed methods study on lay involvement in public health programme delivery. The study design drew on…

  8. Understanding the Cognitive and Affective Mechanisms that Underlie Proxy Risk Perceptions among Caregivers of Asthmatic Children.

    Science.gov (United States)

    Shepperd, James A; Lipsey, Nikolette P; Pachur, Thorsten; Waters, Erika A

    2018-07-01

    Medical decisions made on behalf of another person-particularly those made by adult caregivers for their minor children-are often informed by the decision maker's beliefs about the treatment's risks and benefits. However, we know little about the cognitive and affective mechanisms influencing such "proxy" risk perceptions and about how proxy risk perceptions are related to prominent judgment phenomena. Adult caregivers of minor children with asthma ( N = 132) completed an online, cross-sectional survey assessing 1) cognitions and affects that form the basis of the availability, representativeness, and affect heuristics; 2) endorsement of the absent-exempt and the better-than-average effect; and 3) proxy perceived risk and unrealistic comparative optimism of an asthma exacerbation. We used the Pediatric Asthma Control and Communication Instrument (PACCI) to assess asthma severity. Respondents with higher scores on availability, representativeness, and negative affect indicated higher proxy risk perceptions and (for representativeness only) lower unrealistic optimism, irrespective of asthma severity. Conversely, respondents who showed a stronger display of the better-than-average effect indicated lower proxy risk perceptions but did not differ in unrealistic optimism. The absent-exempt effect was unrelated to proxy risk perceptions and unrealistic optimism. Heuristic judgment processes appear to contribute to caregivers' proxy risk perceptions of their child's asthma exacerbation risk. Moreover, the display of other, possibly erroneous, judgment phenomena is associated with lower caregiver risk perceptions. Designing interventions that target these mechanisms may help caregivers work with their children to reduce exacerbation risk.

  9. 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.

  10. Photospheric activity of the Sun with VIRGO and GOLF. Comparison with standard activity proxies

    Science.gov (United States)

    Salabert, D.; García, R. A.; Jiménez, A.; Bertello, L.; Corsaro, E.; Pallé, P. L.

    2017-12-01

    We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed 21 yr of observations, spanning solar cycles 23 and 24, collected by the space-based photometric VIRGO and radial velocity GOLF instruments on board the SoHO satellite. We then calculated the photospheric activity proxy Sph is for each of the three VIRGO photometers and the associated Svel proxy from the radial velocity GOLF observations. Comparisons with several standard solar activity proxies sensitive to different layers of the Sun demonstrate that these new activity proxies, Sph and Svel, provide a new manner to monitor solar activity. We show that both the long- and short-term magnetic variabilities respectively associated with the 11-yr cycle and the quasi-biennial oscillation are well monitored, and that the magnetic field interaction between the subsurface, photosphere, and chromosphere of the Sun was modified between Cycle 24 and Cycle 23. Furthermore, the photometric proxies show a wavelength dependence of the response function of the solar photosphere among the three channels of the VIRGO photometers, providing inputs for the study of the stellar magnetism of Sun-like stars.

  11. 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 E 2 (PGE 2 ), 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 PGE 2 , 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. PGE 2 , 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.

  12. Validating a proxy for disease progression in metastatic cancer patients using prescribing and dispensing data.

    Science.gov (United States)

    Joshi, Vikram; Adelstein, Barbara-Ann; Schaffer, Andrea; Srasuebkul, Preeyaporn; Dobbins, Timothy; Pearson, Sallie-Anne

    2017-10-01

    Routine data collections are used increasingly to examine outcomes of real-world cancer drug use. These datasets lack clinical details about important endpoints such as disease progression. To validate a proxy for disease progression in metastatic cancer patients using prescribing and dispensing claims. We used data from a cohort study of patients undergoing chemotherapy who provided informed consent to the collection of cancer-treatment data from medical records and linkage to pharmaceutical claims. We derived proxy decision rules based on changes to drug treatment in prescription histories (n = 36 patients) and validated the proxy in prescribing data (n = 62 patients). We adapted the decision rules and validated the proxy in dispensing data (n = 109). Our gold standard was disease progression ascertained in patient medical records. Individual progression episodes were the unit of analysis for sensitivity and Positive Predictive Value (PPV) calculations and specificity and Negative Predictive Value (NPV) were calculated at the patient level. The sensitivity of our proxy in prescribing data was 74.3% (95% Confidence Interval (CI), 55.6-86.6%) and PPV 61.2% (95% CI, 45.0-75.3%); specificity and NPV were 87.8% (95% CI, 73.8-95.9%) and 100% (95% CI, 90.3-100%), respectively. In dispensing data, the sensitivity of our proxy was 64% (95% CI, 55.0-77.0%) and PPV 56.0% (95% CI, 43.0-69.0%); specificity and NPV were 81% (95% CI, 70.05-89.0%) and 91.0% (95% CI, 82.0-97.0%), respectively. Our proxy overestimated episodes of disease progression. The proxy's performance is likely to improve if the date of prescribing is used instead of date of dispensing in claims data and by incorporating medical service claims (such as imaging prior to drug changes) in the algorithm. Our proxy is not sufficiently robust for use in real world comparative effectiveness research for cancer medicines. © 2016 John Wiley & Sons Australia, Ltd.

  13. The relationship between proxy reported health-related quality of life and parental distress: gender differences.

    Science.gov (United States)

    Davis, E; Davies, B; Waters, E; Priest, N

    2008-11-01

    Although primary caregiver proxy reports of health-related quality of life (HRQOL) are often used for healthcare decision making when child self-reports are unable to be collected (because of a variety of reasons such as child illness, disability or age), we have little understanding of the correlates of parent-proxy reports. The aim of this study was to examine the relationship between parental depression and parent-proxy reported QOL for primary caregivers (mothers and fathers), using a multidimensional HRQOL instrument. It was hypothesized that maternal depression would be negatively correlated with maternal reported HRQOL, but that paternal depression would not be correlated with paternal reported HRQOL. Data were from parents of children aged 4-5 years (n = 4983) involved in the Longitudinal Study of Australian Children. A questionnaire assessing parental depression (Kessler-6) and proxy reported HRQOL (Pediatric Quality of Life Inventory) was completed by the primary caregiver. For maternal primary caregivers, maternal depression was negatively correlated with all domains of maternal proxy reports of HRQOL (r = -0.24 to r = -0.36). For paternal primary caregivers, there was no relationship between paternal depression and paternal proxy reports of HRQOL. Multiple regression analyses demonstrated that maternal depression was a significant predictor of total HRQOL, accounting for 12% of the variance. For paternal mental health, depression did not predict parent-proxy reported total HRQOL. These results highlight the importance of assessing maternal mental health when measuring proxy reported QOL. Further research is needed in this area to examine the relationship between parental depression and proxy reported HRQOL (including both mothers and fathers, where possible), as well as child self-reported HRQOL.

  14. Management of Multi-Casualty Incidents in Mountain Rescue: Evidence-Based Guidelines of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM).

    Science.gov (United States)

    Blancher, Marc; Albasini, François; Elsensohn, Fidel; Zafren, Ken; Hölzl, Natalie; McLaughlin, Kyle; Wheeler, Albert R; Roy, Steven; Brugger, Hermann; Greene, Mike; Paal, Peter

    2018-02-15

    Blancher, Marc, François Albasini, Fidel Elsensohn, Ken Zafren, Natalie Hölzl, Kyle McLaughlin, Albert R. Wheeler III, Steven Roy, Hermann Brugger, Mike Greene, and Peter Paal. Management of multi-casualty incidents in mountain rescue. High Alt Med Biol. 00:000-000, 2018. Multi-Casualty Incidents (MCI) occur in mountain areas. Little is known about the incidence and character of such events, and the kind of rescue response. Therefore, the International Commission for Mountain Emergency Medicine (ICAR MEDCOM) set out to provide recommendations for the management of MCI in mountain areas. Details of MCI occurring in mountain areas related to mountaineering activities and involving organized mountain rescue were collected. A literature search using (1) PubMed, (2) national mountain rescue registries, and (3) lay press articles on the internet was performed. The results were analyzed with respect to specific aspects of mountain rescue. We identified 198 MCIs that have occurred in mountain areas since 1956: 137 avalanches, 38 ski lift accidents, and 23 other events, including lightning injuries, landslides, volcanic eruptions, lost groups of people, and water-related accidents. General knowledge on MCI management is required. Due to specific aspects of triage and management, the approach to MCIs may differ between those in mountain areas and those in urban settings. Mountain rescue teams should be prepared to manage MCIs. Knowledge should be reviewed and training performed regularly. Cooperation between terrestrial rescue services, avalanche safety authorities, and helicopter crews is critical to successful management of MCIs in mountain areas.

  15. Nitrogen isotopes from terrestrial organic matter as a new paleoclimatic proxy for pre-quaternary time

    Science.gov (United States)

    Tramoy, romain; Schnyder, johann; thuy Nguyen Tu, thanh; Yans, johan; Storme, jean yves; Sebilo, mathieu; Derenne, sylvie; Jacob, jérémy; Baudin, françois

    2014-05-01

    Marine and lacustrine sedimentary organic matter is often dominated by algal-bacterial production. Its nitrogen isotopic composition (δ15Norg) is frequently used to reconstruct biogeochemical processes involved in the nitrogen cycle, such as N utilization by organisms (e.g. Altabet et al., 1995), denitrification and diagenesis processes (e.g. Altabet et al., 1995; Sebilo et al., 2003; Gälman et al., 2009) or to evidence N sources variability (e.g. Hodell and Schelske, 1998; Vreca and Muri, 2006) . However, all these parameters and processes make N isotopic signals in marine and lacustrine environments often very complex to interpret. After pioneer studies, Mariotti et al. (1981), Austin and Vitousek (1998), Amundson et al. (2003), Swap et al. (2004), and Liu and Wang (2008) have shown that the δ15Norg of modern or quaternary terrestrial plants seem to be positively correlated with temperature and negatively correlated with precipitations. Therefore, δ15Norg of terrestrial OM might be a better record for paleoclimatic studies than δ15Norg of sedimentary OM dominated by algal-bacterial production. Recently, promising organic nitrogen isotopic data (δ15Norg) have been published on lignites from the Dieppe-Hampshire Basin (Paleocene-Eocene transition, Normandy (Storme et al., 2012). Authors suggest that the δ15Norg recorded local paleoclimatic and paleoenvironmental conditions. Following these results, the aim of this work is to test the use of stable nitrogen isotopes in terrestrial OM as a new paleoclimatic marker for pre-quaternary geological series. Does δ15Norg constitute a valuable tool to reconstruct past climates? What are the limits in the use of this proxy and possible methodological bias related to organic sources or diagenetic processes? To address these questions, δ15Norg must be measured in samples from periods associated with large and well documented climate change. We therefore selected a Liassic continental sedimentary succession from

  16. Sincronización de estadísticas entre servidores y proxies

    OpenAIRE

    Catullo, María José

    1999-01-01

    Un caching proxy server colecciona todas las páginas que pasan a través de él, así cuando un usuario pregunta por una página, el proxy server, si la tiene, la retoma de su cache, sin necesidad de acceder al servidor real. De ésta manera se ahorra ancho de banda y se agilizan las respuestas. Cada requerimiento que arriba a un proxy ó a un servidor, se almacena en archivos de logs. Existen varios tipos de archivos de logs, que se utilizan para auditoría del rendimiento, monitoreo, control de...

  17. A Multi-Level Examination of Stakeholder Perspectives of Implementation of Evidence-Based Practices in a Large Urban Publicly-Funded Mental Health System.

    Science.gov (United States)

    Beidas, Rinad S; Stewart, Rebecca E; Adams, Danielle R; Fernandez, Tara; Lustbader, Susanna; Powell, Byron J; Aarons, Gregory A; Hoagwood, Kimberly E; Evans, Arthur C; Hurford, Matthew O; Rubin, Ronnie; Hadley, Trevor; Mandell, David S; Barg, Frances K

    2016-11-01

    Our goal was to identify barriers and facilitators to the implementation of evidence-based practices from the perspectives of multiple stakeholders in a large publicly funded mental health system. We completed 56 interviews with three stakeholder groups: treatment developers (n = 7), agency administrators (n = 33), and system leadership (n = 16). The three stakeholder groups converged on the importance of inner (e.g., agency competing resources and demands, therapist educational background) and outer context (e.g., funding) factors as barriers to implementation. Potential threats to implementation and sustainability included the fiscal landscape of community mental health clinics and an evolving workforce. Intervention characteristics were rarely endorsed as barriers. Inner context, outer context, and intervention characteristics were all seen as important facilitators. All stakeholders endorsed the importance of coordinated collaboration across stakeholder groups within the system to successfully implement evidence-based practices.

  18. Consistent regional fluxes of CH4 and CO2 inferred from GOSAT proxy XCH4 : XCO2 retrievals, 2010-2014

    Science.gov (United States)

    Feng, Liang; Palmer, Paul I.; Bösch, Hartmut; Parker, Robert J.; Webb, Alex J.; Correia, Caio S. C.; Deutscher, Nicholas M.; Domingues, Lucas G.; Feist, Dietrich G.; Gatti, Luciana V.; Gloor, Emanuel; Hase, Frank; Kivi, Rigel; Liu, Yi; Miller, John B.; Morino, Isamu; Sussmann, Ralf; Strong, Kimberly; Uchino, Osamu; Wang, Jing; Zahn, Andreas

    2017-04-01

    We use the GEOS-Chem global 3-D model of atmospheric chemistry and transport and an ensemble Kalman filter to simultaneously infer regional fluxes of methane (CH4) and carbon dioxide (CO2) directly from GOSAT retrievals of XCH4 : XCO2, using sparse ground-based CH4 and CO2 mole fraction data to anchor the ratio. This work builds on the previously reported theory that takes into account that (1) these ratios are less prone to systematic error than either the full-physics data products or the proxy CH4 data products; and (2) the resulting CH4 and CO2 fluxes are self-consistent. We show that a posteriori fluxes inferred from the GOSAT data generally outperform the fluxes inferred only from in situ data, as expected. GOSAT CH4 and CO2 fluxes are consistent with global growth rates for CO2 and CH4 reported by NOAA and have a range of independent data including new profile measurements (0-7 km) over the Amazon Basin that were collected specifically to help validate GOSAT over this geographical region. We find that large-scale multi-year annual a posteriori CO2 fluxes inferred from GOSAT data are similar to those inferred from the in situ surface data but with smaller uncertainties, particularly over the tropics. GOSAT data are consistent with smaller peak-to-peak seasonal amplitudes of CO2 than either the a priori or in situ inversion, particularly over the tropics and the southern extratropics. Over the northern extratropics, GOSAT data show larger uptake than the a priori but less than the in situ inversion, resulting in small net emissions over the year. We also find evidence that the carbon balance of tropical South America was perturbed following the droughts of 2010 and 2012 with net annual fluxes not returning to an approximate annual balance until 2013. In contrast, GOSAT data significantly changed the a priori spatial distribution of CH4 emission with a 40 % increase over tropical South America and tropical Asia and a smaller decrease over Eurasia and temperate

  19. Evaluation of the convergence between "self-reporters" and "proxies" in a disability questionnaire by means of behaviour coding method

    NARCIS (Netherlands)

    Benitez Baena, Isabel; Padilla Garcia, Jose Luis; Ongena, Yfke

    Household surveys often require including proxy reporters to obtain information about other household members who cannot be interviewed. The participation of proxies can undermine survey data quality due to the fact that proxies must respond to questions thinking about other people. The objectives

  20. Longitudinal proxy measurements in multiple sclerosis: patient-proxy agreement on the impact of MS on daily life over a period of two years

    Directory of Open Access Journals (Sweden)

    Thompson Alan J

    2008-02-01

    Full Text Available Abstract Background The use of self-report measurements in clinical settings is increasing. However, in patients with limitations that interfere with reliable self-assessment such as cognitive impairment or mood disturbances, as may be the case in multiple sclerosis (MS, data collection might be problematic. In these situations, information obtained from proxy respondents (e.g. partners may replace self-ratings. The aim of this study was to examine the value of proxy ratings at separate points in time and to assess patient-proxy agreement on possible changes in disease impact of MS. Methods Fifty-six MS patients and their partners completed the Multiple Sclerosis Impact Scale (MSIS-29 at baseline and follow-up, two years later. Patient-proxy agreement was assessed at both time points by calculating intraclass correlation coefficients (ICCs, exact and global agreement and the mean directional differences between groups. Agreement of change over time was assessed by calculating ICCs between change scores. In parallel, global ratings of both patients and proxy respondents of the extent to which the patient had improved or deteriorated over the past two years were collected to validate possible changes on the MSIS-29. Results At both time points, agreement on the physical scale was higher than agreement on the psychological scale (ICCs at baseline were 0.81 for the physical scale and 0.72 for the psychological scale; at follow-up, the ICC values were 0.86 and 0.65 respectively. At follow-up, statistically significant mean differences between patients and proxies were noted for the physical scale (-4.8 ± 12.7, p = 0.006 and the psychological scale (-8.9 ± 18.8, p = 0.001. Agreement between change scores on the MSIS-29 was fair (ICC Conclusion Proxy respondents could act as a reliable source of information in cross-sectional studies. Moreover, results suggested that agreement on change over time might be better for proxy respondents compared to

  1. Prevalence and determinants of misreporting among European children in proxy-reported 24 h dietary recalls.

    Science.gov (United States)

    Börnhorst, C; Huybrechts, I; Ahrens, W; Eiben, G; Michels, N; Pala, V; Molnár, D; Russo, P; Barba, G; Bel-Serrat, S; Moreno, L A; Papoutsou, S; Veidebaum, T; Loit, H-M; Lissner, L; Pigeot, I

    2013-04-14

    Dietary assessment is strongly affected by misreporting (both under- and over-reporting), which results in measurement error. Knowledge about misreporting is essential to correctly interpret potentially biased associations between diet and health outcomes. In young children, dietary data mainly rely on proxy respondents but little is known about determinants of misreporting here. The present analysis was conducted within the framework of the multi-centre IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) study and is based on 6101 children aged 2-9 years with 24 h dietary recall (24-HDR) and complete covariate information. Adapted Goldberg cut-offs were applied to classify the 24-HDR as 'over-report', 'plausible report' or 'under-report'. Backward elimination in the course of multi-level logistic regression analyses was conducted to identify factors significantly related to under- and over-reporting. Next to characteristics of the children and parents, social factors and parental concerns/perceptions concerning their child's weight status were considered. Further selective misreporting was addressed, investigating food group intakes commonly perceived as more or less socially desirable. Proportions of under-, plausible and over-reports were 8.0, 88.6 and 3.4 %, respectively. The risk of under-reporting increased with age (OR 1.19, 95 % CI 1.05, 1.83), BMI z-score of the child (OR 1.23, 95 % CI 1.10, 1.37) and household size (OR 1.12, 95 % CI 1.01, 1.25), and was higher in low/medium income groups (OR 1.45, 95 % CI 1.13, 1.86). Over-reporting was negatively associated with BMI z-scores of the child (OR 0.78, 95 % CI 0.69, 0.88) and higher in girls (OR 1.70, 95 % CI 1.27, 2.28). Further social desirability and parental concerns/perceptions seemed to influence the reporting behaviour. Future studies should involve these determinants of misreporting when investigating diet-disease relationships in children

  2. Constraining Lipid Biomarker Paleoclimate Proxies in a Small Arctic Watershed

    Science.gov (United States)

    Dion-Kirschner, H.; McFarlin, J. M.; Axford, Y.; Osburn, M. R.

    2017-12-01

    Arctic amplification of climate change renders high-latitude environments unusually sensitive to changes in climatic conditions (Serreze and Barry, 2011). Lipid biomarkers, and their hydrogen and carbon isotopic compositions, can yield valuable paleoclimatic and paleoecological information. However, many variables affect the production and preservation of lipids and their constituent isotopes, including precipitation, plant growth conditions, biosynthesis mechanisms, and sediment depositional processes (Sachse et al., 2012). These variables are particularly poorly constrained for high-latitude environments, where trees are sparse or not present, and plants grow under continuous summer light and cool temperatures during a short growing season. Here we present a source-to-sink study of a single watershed from the Kangerlussuaq region of southwest Greenland. Our analytes from in and around `Little Sugarloaf Lake' (LSL) include terrestrial and aquatic plants, plankton, modern lake water, surface sediments, and a sediment core. This diverse sample set allows us to fulfill three goals: 1) We evaluate the production of lipids and isotopic signatures in the modern watershed in comparison to modern climate. Our data exhibit genus-level trends in leaf wax production and isotopic composition, and help clarify the difference between terrestrial and aquatic signals. 2) We evaluate the surface sediment of LSL to determine how lipid biomarkers from the watershed are incorporated into sediments. We constrain the relative contributions of terrestrial plants, aquatic plants, and other aquatic organisms to the sediment in this watershed. 3) We apply this modern source-to-sink calibration to the analysis of a 65 cm sediment core record. Our core is organic-rich, and relatively high deposition rates allow us to reconstruct paleoenvironmental changes with high resolution. Our work will help determine the veracity of these common paleoclimate proxies, specifically for research in

  3. The geomorphological evidences of subsidence in the Nile Delta: Analysis of high resolution topographic DEM and multi-temporal satellite images

    Science.gov (United States)

    El Bastawesy, M.; Cherif, O. H.; Sultan, M.

    2017-12-01

    This paper investigates the relevance of landforms to the subsidence of the Nile Delta using a high resolution topographic digital elevation model (DEM) and sets of multi-temporal Landsat satellite images. 195 topographic map sheets produced in 1946 at 1:25,000 scale were digitized, and the DEM was interpolated. The undertaken processing techniques have distinguished all the natural low-lying closed depressions from the artificial errors induced by the interpolation of the DEM. The local subsidence of these depressions from their surroundings reaches a maximum depth of 2.5 m. The regional subsidence of the Nile Delta has developed inverted topography, where the tracts occupied by the contemporary distributary channels are standing at higher elevations than the areas in between. This inversion could be related to the differences in the hydrological and sedimentological properties of underlying sediments, as the channels are underlain by water-saturated sands while the successions of clay and silt on flood plains are prone to compaction. Furthermore, the analysis of remote sensing and topographic data clearly show significant changes in the land cover and land use, particularly in the northern lagoons and adjacent sabkhas, which are dominated by numerous low subsiding depressions. The areas covered by water logging and ponds are increasing on the expense of agricultural areas, and aquaculture have been practiced instead. The precise estimation of subsidence rates and distribution should be worked out to evaluate probable changes in land cover and land use.

  4. A multi-site randomised controlled trial of evidence-based supported employment for adults with severe and persistent mental illness.

    Science.gov (United States)

    Waghorn, Geoffrey; Dias, Shannon; Gladman, Beverley; Harris, Meredith; Saha, Sukanta

    2014-12-01

    The Individual Placement and Support (IPS) approach is an evidence-based form of supported employment for people with severe and persistent mental illness. This approach is not yet widely available in Australia even though there is mounting evidence of its generalisability outside the USA. One previous Australian randomised controlled trial found that IPS is effective for young people with first episode psychosis. The aim of the current trial was to assess the effectiveness of evidence-based supported employment when implemented for Australian adult consumers of public mental health services by utilising existing service systems. A four-site randomised control trial design (n = 208) was conducted in Brisbane (two sites), Townsville and Cairns. The intervention consisted of an IPS supported employment service hosted by a community mental health team. The control condition was delivered at each site by mental health teams referring consumers to other disability employment services in the local area. At 12 months, those in the IPS condition had 2.4 times greater odds of commencing employment than those in the control condition (42.5% vs. 23.5%). The conditions did not differ on secondary employment outcomes including job duration, hours worked, or job diversity. Attrition was higher than expected in both conditions with 28.4% completing the baseline interview but taking no further part in the study. The results support previous international findings that IPS-supported employment is more effective than non-integrated supported employment. IPS can be successfully implemented this way in Australia, but with a loss of effect strength compared to previous USA trials. © 2014 Occupational Therapy Australia.

  5. RESPONSE OF THREE PALEO-PRIMARY PRODUCTION PROXY MEASURES TO DEVELOPMENT OF AN URBAN ESTUARY

    Science.gov (United States)

    In this study we present a novel comparison of three proxy indicators of paleoproductivity, pigments, biogenic silica (BSi), and cysts of autotrophic dinoflagellates measured in cored sediments from New Bedford Harbor, Massachusetts. In addition to detailed historical reports we ...

  6. 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...

  7. 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

  8. Sea ice and primary production proxies in surface sediments from a High Arctic Greenland fjord

    DEFF Research Database (Denmark)

    Ribeiro, Sofia; Sejr, Mikael K; Limoges, Audrey

    2017-01-01

    Monitoring Programme. Clear spatial gradients in organic carbon and biogenic silica contents reflected marine influence, nutrient availability and river-induced turbidity, in good agreement with in situ measurements. The sea ice proxy IP25 was detected at all sites but at low concentrations, indicating...... that IP25 records from fjords need to be carefully considered and not directly compared to marine settings. The sea ice-associated biomarker HBI III revealed an open-water signature, with highest concentrations near the mid-July ice edge. This proxy evaluation is an important step towards reliable......In order to establish a baseline for proxy-based reconstructions for the Young Sound–Tyrolerfjord system (Northeast Greenland), we analysed the spatial distribution of primary production and sea ice proxies in surface sediments from the fjord, against monitoring data from the Greenland Ecosystem...

  9. Technical Note: Correcting for signal attenuation from noisy proxy data in climate reconstructions

    KAUST Repository

    Ammann, C. M.; Genton, M. G.; Li, B.

    2010-01-01

    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

  10. Usable Authentication with an Offline Trusted Device Proxy Architecture (long version)

    OpenAIRE

    Johansen, Christian; Jøsang, Audun; Migdal, Denis

    2016-01-01

    Client platform infection poses a significant threat to secure user authentication. Com- bining vulnerable client platforms with special security devices, as often the case in e- banking, can increase significantly the security. This paper describes a new architecture where a security proxy on the client platform communicates with both a trusted security device and the server application. The proxy switches between two TLS channels, one from the client and another from the trusted device. The...

  11. 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.

  12. Reliability of proxy respondents for patients with stroke: a systematic review.

    Science.gov (United States)

    Oczkowski, Colin; O'Donnell, Martin

    2010-01-01

    Proxy respondents are an important aspect of stroke medicine and research. We performed a systematic review of studies evaluating the reliability of proxy respondents for stroke patients. Studies were identified by searches of MEDLINE, Google, and the Cochrane Library between January 1969 and June 2008. All were prospective or cross-sectional studies reporting the reliability of proxy respondents for patients with a history of previous stroke or transient ischemic attack. One author abstracted data. For each study, intraclass correlation (ICC) or the k-statistic was categorized as poor (0.80). Thirteen studies, with a total of 2618 participants, met our inclusion criteria. Most studies recruited patients >3 months after their stroke. Of these studies, 5 (360 participants; 5 scales) evaluated reliability of proxy respondents for activities of daily living (ADL), and 9 (2334 participants; 9 scales) evaluated reliability of proxy respondents for quality of life (QoL). One study evaluated both. In studies, the ICC/k for scales ranged from 0.61 to 0.91 for ADL and from 0.41 to 0.8 for QoL. Most studies reported that proxy respondents overestimated impairments compared with patient self-reports. Stroke severity and objective nature of questions were the most consistent determinants of disagreement between stroke patient and proxy respondent. Our data indicate that beyond the acute stroke period, the reliability of proxy respondents for validated scales of ADL was substantial to excellent, while that of scales for QoL was moderate to substantial. Copyright (c) 2010 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  13. Proxy-Reports in the Ascertainment of Disability Prevalence with American Community Survey Data.

    Science.gov (United States)

    Siordia, C

    2014-01-01

    Population estimates on disability prevalence inform policy makers and public health professionals. Understanding how factors capable of affecting measurement (e.g., proxy-report) vary in the population is important for establishing level of confidence in sample-derived population estimates. To establish how use of proxy-reports varies by six disability types stratified by sex, race-ethnicity, and age group. Specific aim is achieved by investigating the number of proxy-reports used amongst the disable population. Cross-sectional study using American Community Survey (ACS) Public Use Microdata Sample (PUMS) 3-year file collected during 2009-2011 survey period. Community-dwelling population in continental United States (US). The unweighted count of 6,003,183 individuals in the microdata are said to represent about 193,277,485 individuals in the continental US population. Stratified disability period estimates are computed. Amongst the disable: the number of proxy-reports; allocations; and Person Inflation Ratios (PRIs) are presented by disability type. Half of all the reported disabilities are derived through the use of proxy-report. In addition, high rates of item-allocation and PRIs are generally found in race-ethnic minorities. Proxy-report use and PRIs are lower for those aged > 65-but not allocation rates. Although use of proxy report in the ascertainment of disability varies in complex ways, data suggest prevalence of proxy reports is lowest amongst Non-Latino-Black females ages 21 to 64. Efforts toward providing clinicians with high quality descriptive epidemiology should continue as a reliable thermometer for measuring disability in the population is needed.

  14. 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.

  15. Evaluating and Optimizing Online Advertising: Forget the Click, but There Are Good Proxies.

    Science.gov (United States)

    Dalessandro, Brian; Hook, Rod; Perlich, Claudia; Provost, Foster

    2015-06-01

    Online systems promise to improve advertisement targeting via the massive and detailed data available. However, there often is too few data on exactly the outcome of interest, such as purchases, for accurate campaign evaluation and optimization (due to low conversion rates, cold start periods, lack of instrumentation of offline purchases, and long purchase cycles). This paper presents a detailed treatment of proxy modeling, which is based on the identification of a suitable alternative (proxy) target variable when data on the true objective is in short supply (or even completely nonexistent). The paper has a two-fold contribution. First, the potential of proxy modeling is demonstrated clearly, based on a massive-scale experiment across 58 real online advertising campaigns. Second, we assess the value of different specific proxies for evaluating and optimizing online display advertising, showing striking results. The results include bad news and good news. The most commonly cited and used proxy is a click on an ad. The bad news is that across a large number of campaigns, clicks are not good proxies for evaluation or for optimization: clickers do not resemble buyers. The good news is that an alternative sort of proxy performs remarkably well: observed visits to the brand's website. Specifically, predictive models built based on brand site visits-which are much more common than purchases-do a remarkably good job of predicting which browsers will make a purchase. The practical bottom line: evaluating and optimizing campaigns using clicks seems wrongheaded; however, there is an easy and attractive alternative-use a well-chosen site-visit proxy instead.

  16. Multi-decadal shoreline changes on Takú Atoll, Papua New Guinea: Observational evidence of early reef island recovery after the impact of storm waves

    Science.gov (United States)

    Mann, Thomas; Westphal, Hildegard

    2016-03-01

    Hurricanes, tropical cyclones and other high-magnitude events are important steering mechanisms in the geomorphic development of coral reef islands. Sandy reef islands located outside the storm belts are strongly sensitive to the impact of occasional high-magnitude events and show abrupt, commonly erosive geomorphic change in response to such events. Based on the interpretation of remote sensing data, it is well known that the process of landform recovery might take several decades or even longer. However, despite the increasing amount of scientific attention towards short- and long-term island dynamics, the lack of data and models often prevent a robust analysis of the timing and nature of recovery initiation. Here we show how natural island recovery starts immediately after the impact of a high-magnitude event. We analyze multi-temporal shoreline changes on Takú Atoll, Papua New Guinea and combine our findings with a unique set of published field observations (Smithers and Hoeke, 2014). Trends of shoreline change since 1943 and changes in planform island area indicate a long-term accretionary mode for most islands. Apparent shoreline instability is detected for the last decade of analysis, however this can be explained by the impact of storm waves in December 2008 that (temporarily?) masked the long-term trend. The transition from negative to positive rates of change in the aftermath of this storm event is indicative of inherent negative feedback processes that counteract short-term changes in energy input and represent the initiation of island recovery. Collectively, our results support the concept of dynamic rather than static reef islands and clearly demonstrate how short-term processes can influence interpretations of medium-term change.

  17. Neighborhood Prices of Healthier and Unhealthier Foods and Associations with Diet Quality: Evidence from the Multi-Ethnic Study of Atherosclerosis.

    Science.gov (United States)

    Kern, David M; Auchincloss, Amy H; Stehr, Mark F; Roux, Ana V Diez; Moore, Latetia V; Kanter, Genevieve P; Robinson, Lucy F

    2017-11-16

    It is known that the price of food influences the purchasing and consumption decisions of individuals; however, little work has examined if the price of healthier food relative to unhealthier food in an individual's neighborhood is associated with overall dietary quality while using data from multiple regions in the United States. Cross-sectional person-level data came from The Multi-Ethnic Study of Atherosclerosis (exam 5, 2010-2012 n = 2765); a food frequency questionnaire assessed diet. Supermarket food/beverage prices came from Information Resources Inc. (n = 794 supermarkets). For each individual, the average price of select indicators of healthier foods (vegetables, fruits, dairy) and unhealthier foods (soda, sweets, salty snacks), as well as their ratio, was computed for supermarkets within three miles of the person's residential address. Logistic regression estimated odds ratios of a high-quality diet (top quintile of Healthy Eating Index 2010) associated with healthy-to-unhealthy price ratio, adjusted for individual and neighborhood characteristics. Sensitivity analyses used an instrumental variable (IV) approach. Healthier foods cost nearly twice as much as unhealthier foods per serving on average (mean healthy-to-unhealthy ratio = 1.97 [SD 0.14]). A larger healthy-to-unhealthy price ratio was associated with lower odds of a high-quality diet (OR = 0.76 per SD increase in the ratio, 95% CI = [0.64-0.9]). IV analyses largely confirmed these findings although-as expected with IV adjustment-confidence intervals were wide (OR = 0.82 [0.57-1.19]). Policies to address the large price differences between healthier and unhealthy foods may help improve diet quality in the United States.

  18. Neighborhood Prices of Healthier and Unhealthier Foods and Associations with Diet Quality: Evidence from the Multi-Ethnic Study of Atherosclerosis

    Directory of Open Access Journals (Sweden)

    David M. Kern

    2017-11-01

    Full Text Available It is known that the price of food influences the purchasing and consumption decisions of individuals; however, little work has examined if the price of healthier food relative to unhealthier food in an individual’s neighborhood is associated with overall dietary quality while using data from multiple regions in the United States. Cross-sectional person-level data came from The Multi-Ethnic Study of Atherosclerosis (exam 5, 2010–2012, n = 2765; a food frequency questionnaire assessed diet. Supermarket food/beverage prices came from Information Resources Inc. (n = 794 supermarkets. For each individual, the average price of select indicators of healthier foods (vegetables, fruits, dairy and unhealthier foods (soda, sweets, salty snacks, as well as their ratio, was computed for supermarkets within three miles of the person’s residential address. Logistic regression estimated odds ratios of a high-quality diet (top quintile of Healthy Eating Index 2010 associated with healthy-to-unhealthy price ratio, adjusted for individual and neighborhood characteristics. Sensitivity analyses used an instrumental variable (IV approach. Healthier foods cost nearly twice as much as unhealthier foods per serving on average (mean healthy-to-unhealthy ratio = 1.97 [SD 0.14]. A larger healthy-to-unhealthy price ratio was associated with lower odds of a high-quality diet (OR = 0.76 per SD increase in the ratio, 95% CI = [0.64–0.9]. IV analyses largely confirmed these findings although—as expected with IV adjustment—confidence intervals were wide (OR = 0.82 [0.57–1.19]. Policies to address the large price differences between healthier and unhealthy foods may help improve diet quality in the United States.

  19. Betel-quid dependence domains and syndrome associated with betel-quid ingredients among chewers: an Asian multi-country evidence.

    Science.gov (United States)

    Lee, Chien-Hung; Chiang, Shang-Lun; Ko, Albert Min-Shan; Hua, Chun-Hung; Tsai, Ming-Hsui; Warnakulasuriya, Saman; Ibrahim, Salah Osman; Sunarjo; Zain, Rosnah Binti; Ling, Tian-You; Huang, Chieh-Liang; Lane, Hsien-Yuan; Lin, Cheng-Chieh; Ko, Ying-Chin

    2014-07-01

    Betel-quid (BQ) contains biologically psychoactive ingredients; however, data are limited concerning the symptoms and syndrome of BQ dependence among chewers. The aims of this study were to evaluate the ingredients-associated BQ dependence syndrome and country-specific chewing features and behaviour for BQ dependence among chewers from six Asian communities. An intercountry Asian Betel-quid Consortium study. Six Asian general communities in Taiwan, Mainland China, Indonesia, Malaysia, Sri Lanka and Nepal. Six multi-stage random samples of BQ chewers in the Asian Betel-quid Consortium study (n = 2078). All chewers were evaluated for BQ dependence using the DSM-IV and ICD-10 criteria. The 12-month BQ dependence rate was 12.5-92.6% and 47.9-99.3% (P = 0.023) among tobacco-free and tobacco-added BQ chewers across the six Asian communities, with a higher dependence rate in chewers who used tobacco-free BQ with lime added than without (23.3-95.6% versus 4.0%, P ≤ 0.001). Taiwanese and Hunanese BQ chewers both notably endorsed the dependency domain of 'time spent chewing'. 'Tolerance' and 'withdrawal' were the major dependence domains associated with the Nepalese and Indonesian chewers, with high BQ dependence rates. Malaysian and Sri Lankan chewers formed a BQ dependence cluster linked closely to 'craving'. In Sri Lanka, the quantity consumed explained 90.5% (P betel quid users in Asian communities, more so if they use it with tobacco or lime. © 2014 Society for the Study of Addiction.

  20. Violence against women is strongly associated with suicide attempts: evidence from the WHO multi-country study on women's health and domestic violence against women.

    Science.gov (United States)

    Devries, Karen; Watts, Charlotte; Yoshihama, Mieko; Kiss, Ligia; Schraiber, Lilia Blima; Deyessa, Negussie; Heise, Lori; Durand, Julia; Mbwambo, Jessie; Jansen, Henrica; Berhane, Yemane; Ellsberg, Mary; Garcia-Moreno, Claudia

    2011-07-01

    Suicidal behaviours are one of the most important contributors to the global burden of disease among women, but little is known about prevalence and modifiable risk factors in low and middle income countries. We use data from the WHO multi-country study on women's health and domestic violence against women to examine the prevalence of suicidal thoughts and attempts, and relationships between suicide attempts and mental health status, child sexual abuse, partner violence and other variables. Population representative cross-sectional household surveys were conducted from 2000-2003 in 13 provincial (more rural) and city (urban) sites in Brazil, Ethiopia, Japan, Namibia, Peru, Samoa, Serbia, Thailand and Tanzania. 20967 women aged 15-49 years participated. Prevalence of lifetime suicide attempts, lifetime suicidal thoughts, and suicidal thoughts in the past four weeks were calculated, and multivariate logistic regression models were fit to examine factors associated with suicide attempts in each site. Prevalence of lifetime suicide attempts ranged from 0.8% (Tanzania) to 12.0% (Peru city); lifetime thoughts of suicide from 7.2% (Tanzania province) to 29.0% (Peru province), and thoughts in the past four weeks from 1.9% (Serbia) to 13.6% (Peru province). 25-50% of women with suicidal thoughts in the past four weeks had also visited a health worker in that time. The most consistent risk factors for suicide attempts after adjusting for probable common mental health disorders were: intimate partner violence, non-partner physical violence, ever being divorced, separated or widowed, childhood sexual abuse and having a mother who had experienced intimate partner violence. Mental health policies and services must recognise the consistent relationship between violence and suicidality in women in low and middle income countries. Training health sector workers to recognize and respond to the consequences of violence may substantially reduce the health burden associated with

  1. Hydraulic Fracture Induced Seismicity During A Multi-Stage Pad Completion in Western Canada: Evidence of Activation of Multiple, Parallel Faults

    Science.gov (United States)

    Maxwell, S.; Garrett, D.; Huang, J.; Usher, P.; Mamer, P.

    2017-12-01

    Following reports of injection induced seismicity in the Western Canadian Sedimentary Basin, regulators have imposed seismic monitoring and traffic light protocols for fracturing operations in specific areas. Here we describe a case study in one of these reservoirs, the Montney Shale in NE British Columbia, where induced seismicity was monitored with a local array during multi-stage hydraulic fracture stimulations on several wells from a single drilling pad. Seismicity primarily occurred during the injection time periods, and correlated with periods of high injection rates and wellhead pressures above fracturing pressures. Sequential hydraulic fracture stages were found to progressively activate several parallel, critically-stressed faults, as illuminated by multiple linear hypocenter patterns in the range between Mw 1 and 3. Moment tensor inversion of larger events indicated a double-couple mechanism consistent with the regional strike-slip stress state and the hypocenter lineations. The critically-stressed faults obliquely cross the well paths which were purposely drilled parallel to the minimum principal stress direction. Seismicity on specific faults started and stopped when fracture initiation points of individual injection stages were proximal to the intersection of the fault and well. The distance ranges when the seismicity occurs is consistent with expected hydraulic fracture dimensions, suggesting that the induced fault slip only occurs when a hydraulic fracture grows directly into the fault and the faults are temporarily exposed to significantly elevated fracture pressures during the injection. Some faults crossed multiple wells and the seismicity was found to restart during injection of proximal stages on adjacent wells, progressively expanding the seismogenic zone of the fault. Progressive fault slip is therefore inferred from the seismicity migrating further along the faults during successive injection stages. An accelerometer was also deployed close

  2. MODELING THE MULTI-BAND AFTERGLOW OF GRB 130831A: EVIDENCE FOR A SPINNING-DOWN MAGNETAR DOMINATED BY GRAVITATIONAL WAVE LOSSES?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Zong, H. S. [School of Physics, Nanjing University, Nanjing 210093 (China); Huang, Y. F., E-mail: zonghs@nju.edu.cn, E-mail: hyf@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China)

    2016-06-01

    The X-ray afterglow of GRB 130831A shows an “internal plateau” with a decay slope of ∼0.8, followed by a steep drop at around 10{sup 5} s with a slope of ∼6. After the drop, the X-ray afterglow continues with a much shallower decay. The optical afterglow exhibits two segments of plateaus separated by a luminous optical flare, followed by a normal decay with a slope basically consistent with that of the late-time X-ray afterglow. The decay of the internal X-ray plateau is much steeper than what we expect in the simplest magnetar model. We propose a scenario in which the magnetar undergoes gravitational-wave-driven r-mode instability, and the spin-down is dominated by gravitational wave losses up to the end of the steep plateau, so that such a relatively steep plateau can be interpreted as the internal emission of the magnetar wind and the sharp drop can be produced when the magnetar collapses into a black hole. This scenario also predicts an initial X-ray plateau lasting for hundreds of seconds with an approximately constant flux which is compatible with observation. Assuming that the magnetar wind has a negligible contribution in the optical band, we interpret the optical afterglow as the forward shock emission by invoking the energy injection from a continuously refreshed shock following the prompt emission phase. It is shown that our model can basically describe the temporal evolution of the multi-band afterglow of GRB 130831A.

  3. System Identification Based Proxy Model of a Reservoir under Water Injection

    Directory of Open Access Journals (Sweden)

    Berihun M. Negash

    2017-01-01

    Full Text Available Simulation of numerical reservoir models with thousands and millions of grid blocks may consume a significant amount of time and effort, even when high performance processors are used. In cases where the simulation runs are required for sensitivity analysis, dynamic control, and optimization, the act needs to be repeated several times by continuously changing parameters. This makes it even more time-consuming. Currently, proxy models that are based on response surface are being used to lessen the time required for running simulations during sensitivity analysis and optimization. Proxy models are lighter mathematical models that run faster and perform in place of heavier models that require large computations. Nevertheless, to acquire data for modeling and validation and develop the proxy model itself, hundreds of simulation runs are required. In this paper, a system identification based proxy model that requires only a single simulation run and a properly designed excitation signal was proposed and evaluated using a benchmark case study. The results show that, with proper design of excitation signal and proper selection of model structure, system identification based proxy models are found to be practical and efficient alternatives for mimicking the performance of numerical reservoir models. The resulting proxy models have potential applications for dynamic well control and optimization.

  4. Pattern-mixture models for analyzing normal outcome data with proxy respondents.

    Science.gov (United States)

    Shardell, Michelle; Hicks, Gregory E; Miller, Ram R; Langenberg, Patricia; Magaziner, Jay

    2010-06-30

    Studies of older adults often involve interview questions regarding subjective constructs such as perceived disability. In some studies, when subjects are unable (e.g. due to cognitive impairment) or unwilling to respond to these questions, proxies (e.g. relatives or other care givers) are recruited to provide responses in place of the subject. Proxies are usually not approached to respond on behalf of subjects who respond for themselves; thus, for each subject, data from only one of the subject or proxy are available. Typically, proxy responses are simply substituted for missing subject responses, and standard complete-data analyses are performed. However, this approach may introduce measurement error and produce biased parameter estimates. In this paper, we propose using pattern-mixture models that relate non-identifiable parameters to identifiable parameters to analyze data with proxy respondents. We posit three interpretable pattern-mixture restrictions to be used with proxy data, and we propose estimation procedures using maximum likelihood and multiple imputation. The methods are applied to a cohort of elderly hip-fracture patients. (c) 2010 John Wiley & Sons, Ltd.

  5. How to integrate proxy data from two informants in life event assessment in psychological autopsy.

    Science.gov (United States)

    Zhang, Jie; Wang, Youqing; Fang, Le

    2018-04-27

    Life event assessment is an important part in psychological autopsy, and how to integrate its proxy data from two informants is a major methodological issue which needs solving. Totally 416 living subjects and their two informants were interviewed by psychological autopsy, and life events were assessed with Paykel's Interview for Recent Life Events. Validities of integrated proxy data using six psychological autopsy information reconstruction methods were evaluated, with living subjects' self-reports used as gold-standard criteria. For all the life events, average value of Youden Indexes for proxy data by type C information reconstruction method (choosing positive value from two informants) was larger than other five methods'. For family life related events, proxy data by type 1st information reconstruction method were not significantly different from living subjects' self-reports (P = 0.828). For all other life events, proxy data by type C information reconstruction method were not significantly different from the gold-standard. Choosing positive value is a relatively better method for integrating dichotomous (positive vs. negative) proxy data from two informants in life event assessment in psychological autopsy, except for family life related events. In that case, using information provided by 1st informants (mainly family member) is recommended.

  6. 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.

  7. 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.

    2018-01-01

    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

  8. 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

  9. Oral health-related quality of life in youth receiving cleft-related surgery: self-report and proxy ratings.

    Science.gov (United States)

    Broder, Hillary L; Wilson-Genderson, Maureen; Sischo, Lacey

    2017-04-01

    This paper evaluated the impact of cleft-related surgery on the oral health-related quality of life (OHRQoL) of youth with cleft over time. Data were derived from a 5-year, multi-center, prospective, longitudinal study of 1196 youth with cleft lip and/or palate and their caregivers. Eligible youth were between 7.5 and 18.5 years old, spoke English or Spanish, and were non-syndromic. During each observational period, which included baseline, and 1- and 2-year post-baseline follow-up visits, youths and their caregivers completed the Child Oral Health Impact Profile, a validated measure of OHRQoL. Multilevel mixed-effects models were used to analyze the effects of receipt of craniofacial surgery on OHRQoL over time. During the course of this study a total of 516 patients (43 %) received at least one surgery. Youth in the surgery recommendation group had lower self- (β = -2.18, p self- and proxy-rated OHRQoL at baseline. Both surgical and non-surgical youth (β = 3.73, p self-reported OHRQoL for youth postsurgery (β = 1.04, p self- and caregiver-rated OHRQoL when compared to non-surgical youth. Youth who underwent cleft-related surgery had significant incremental improvements in self-rated but not caregiver (proxy)-rated OHRQoL after surgery.

  10. Evidence for lower variability of coronary artery calcium mineral mass measurements by multi-detector computed tomography in a community-based cohort-Consequences for progression studies

    International Nuclear Information System (INIS)

    Hoffmann, Udo; Siebert, Uwe; Bull-Stewart, Arabella; Achenbach, Stephan; Ferencik, Maros; Moselewski, Fabian; Brady, Thomas J.; Massaro, Joseph M.; O'Donnell, Christopher J.

    2006-01-01

    Purpose: To compare the measurement variability for coronary artery calcium (CAC) measurements using mineral mass compared with a modified Agatston score (AS) or volume score (VS) with multi-detector CT (MDCT) scanning, and to estimate the potential impact of these methods on the design of CAC progression studies. Materials and methods: We studied 162 consecutive subjects (83 women, 79 men, mean age 51 ± 11 years) from a general Caucasian community-based cohort (Framingham Heart Study) with duplicate runs of prospective electrocardiographically-triggered MDCT scanning. Each scan was independently evaluated for the presence of CAC by four experienced observers who determined a 'modified' AS, VS and mineral mass. Results: Of the 162 subjects, CAC was detected in both scans in 69 (42%) and no CAC was detected in either scan in 72 (45%). Calcium scores were low in the 21/162 subjects (12%) for whom CAC was present in one but not the other scan (modified AS 0.96). However, the mean interscan variability was significantly different between mineral mass, modified AS, and VS (coefficient of variation 26 ± 19%, 41 ± 28% and 34 ± 25%, respectively; p < 0.04), with significantly smaller mean differences in pair-wise comparisons for mineral mass compared with modified AS (p < 0.002) or with VS (p < 0.03). The amount of CAC but not heart rate was an independent predictor of interscan variability (r = -0.638, -0.614 and -0.577 for AS, VS, and mineral mass, respectively; all p < 0.0001). The decreased interscan variability of mineral mass would allow a sample size reduction of 5.5% compared with modified AS for observational studies of CAC progression and for randomized clinical trials. Conclusion: There is significantly reduced interscan variability of CAC measurements with mineral mass compared with the modified AS or VS. However, the measurement variability of all quantification methods is predicted by the amount of CAC and is inversely correlated to the extent of partial

  11. Preservation of Fe Isotope Proxies in the Rock Record

    Science.gov (United States)

    Johnson, C.; Beard, B.; Valley, J.; Valaas, E.

    2005-12-01

    Iron isotope variations provide powerful constraints on redox conditions and pathways involved during biogeochemical cycling of Fe in surface and near-surface environments. The relative isotopic homogeneity of igneous rocks and most bulk weathering products contrasts with the significant isotopic variations (4 per mil in 56Fe/54Fe) that accompany oxidation of Fe(II)aq, precipitation of sulfides, and reduction by bacteria. These isotopic variations often reflect intrinsic (equilibrium) Fe isotope fractionations between minerals and aqueous species whose interactions may be directly or indirectly catalyzed by bacteria. In addition, Fe isotope exchange may be limited between reactive Fe pools in low-temperature aqueous-sediment environments, fundamentally reflecting disequilibrium effects. In the absence of significant sulfide, dissimilatory Fe(III) reduction by bacteria produces relatively low 56Fe/54Fe ratios for Fe(II)aq and associated biogenic minerals such as magnetite and siderite. In contrast, Fe(II)aq that exchanges with Fe sulfides (FeS and pyrite) is relatively enriched in 56Fe/54Fe ratios. In modern and ancient environments, anoxic diagenesis tends to produce products that have low 56Fe/54Fe ratios, whereas oxidation of Fe(II)aq from hydrothermal sources tends to produce ferric Fe products that have high 56Fe/54Fe ratios. Redox cycling by bacteria tends to produce reactive ferric Fe reservoirs that have low 56Fe/54Fe ratios. Application of Fe isotopes as a proxy for redox conditions in the ancient rock record depends upon the preservation potential during metamorphism, given the fact that most Archean sedimentary sequences have been subjected to regional greenschist- to granulite-facies metamorphism. The 1.9 Ga banded iron formations (BIFs) of the Lake Superior region that are intruded by large ~1 Ga intrusions (e.g., Duluth gabbro) provide a test of the preservation potential for primary, low-temperature Fe isotope variations in sedimentary rocks. 56Fe/54

  12. Reliability and validity of a self-administration version of DEMQOL-Proxy.

    Science.gov (United States)

    Hendriks, A A Jolijn; Smith, Sarah C; Chrysanthaki, Theopisti; Black, Nick

    2017-07-01

    This study aimed to investigate the reliability and validity of a self-administered version of DEMQOL-Proxy, a disease-specific instrument that measures health-related quality of life in people with dementia. The sample consisted of 173 informal carers of people with dementia, aged 29 to 89 years old. Carers were mostly female, White/White British and closely related to the patient. They completed DEMQOL-Proxy (self-administered), EQ-5D-3L (proxy reported about the person with dementia), EQ-5D-3L (self-reported about their own health) and the Zarit Burden Interview. Using well-established methods from classical test theory, we evaluated scale level acceptability, reliability and convergent, discriminant and known-groups validity of DEMQOL-Proxy. DEMQOL-Proxy (self-administered) showed high acceptability (3.5% missing data and 0% scores at floor or ceiling), high internal consistency reliability (α = 0.93) and good convergent and discriminant validity. Amongst others, we found a moderately high correlation with EQ-5D-3L proxy reported (r = 0.52) and low to essentially zero correlations with EQ-5D-3L self-reported (r = 0.20) and carer and patient background variables (r ≤ 0.20). As predicted, DEMQOL-Proxy (self-administered) showed a modest correlation with DEMQOL (r = 0.32). Known-groups differences on health-related quality of life (comparing people with versus people without cognitive impairment) were of moderate effect size (d = 0.38) and in the expected direction. DEMQOL-Proxy (self-administered) has comparable acceptability, reliability and validity with DEMQOL-Proxy (interviewer administered). DEMQOL-Proxy (self-administered) can be used in a wider variety of contexts than its interviewer-administered version, including routine use in busy clinics. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar

    Directory of Open Access Journals (Sweden)

    C. A. Grove

    2012-08-01

    Full Text Available Coral cores provide vital climate reconstructions for site-specific temporal variability in river flow and sediment load. Yet, their ability to record spatial differences across multiple catchments is relatively unknown. Here, we investigate spatial linkages between four coral proxies of terrestrial runoff and their relationships between sites. Coral cores were drilled in and around Antongil Bay, the largest bay in Madagascar, and individually analysed for fifteen years of continuous luminescence (G / B, Ba / Ca, δ18Osw and δ13C data. Each coral core was drilled close to individual river mouths (≥ 7 km, and proxy data were compared to modelled river discharge and sediment runoff data for the three corresponding catchments. A reasonable agreement between terrestrial runoff proxies with modelled river discharge and sediment yield was observed. Some inconsistencies between proxy and modelled data are likely linked to proxy behaviour, watershed size and local environmental physiochemical parameters. In general, the further a coral resided from its river source, the weaker the proxy relationship was with modelled data and other corals, due to mixing gradients and currents. Nevertheless, we demonstrate that two coral Ba / Ca and luminescence (G / B records influenced by the same watershed are reproducible. Furthermore, a strong Ba / Ca relationship was observed between two cores from distant watersheds, with baseline averages in agreement with modelled sediment runoff data. As humic acids behave conservatively in the water column, luminescence (G / B data gave the highest regional correlations between cores, and showed the most consistent relationship with site specific modelled discharge. No statistical relationship was observed between cores in terms of interannual δ18Osw and δ13C, meaning corals were recording a localised signal at their respective sites, confounded by vital

  14. Expert versus proxy rating of verbal communicative ability of people with aphasia after stroke.

    Science.gov (United States)

    de Jong-Hagelstein, Marjolein; Kros, Lieke; Lingsma, Hester F; Dippel, Diederik W J; Koudstaal, Peter J; Visch-Brink, Evy G

    2012-11-01

    In randomized clinical trials of aphasia treatment, a functional outcome measure like the Amsterdam-Nijmegen Everyday Language Test (ANELT), administered by speech-language therapists, is often used. However, the agreement between this expert rating and the judgment of the proxy about the quality of the daily life communication of the person with aphasia is largely unknown. We examined the association between ANELT scores by speech-language therapists and proxy judgments on the Partner Communication Questionnaire both at 3 and 6 months in 39 people with aphasia after stroke. We also determined which factors affected the level of agreement between expert and proxy judgment of the communicative ability at 6 months in 53 people with aphasia. We found moderate agreement (at 3 months r = .662; p = aphasia, measured with the Aphasia Severity Rating Scale, was associated with better agreement. In conclusion, although proxies were slightly more positive than experts, we found moderate agreement between expert and proxy rating of verbal communicative ability of people with aphasia after stroke, especially in milder cases.

  15. Completeness and utility of interview data from proxy respondents in prenatal care research in rural China.

    Science.gov (United States)

    Nwaru, Bright I; Klemetti, Reija; Yuan, Shen; Kun, Huang; Wang, Yang; Hemminki, Elina

    2012-05-01

    In household surveys, the use of data provided by relatives can increase response rates and generalisability of research findings. This study assessed the quality of data from relatives and the impact of the data source on the association between the use of prenatal care and pregnancy outcomes. Data for 3,673 new mothers and 293 proxy respondents were available from a house-hold survey in 2008-2009 in rural China. Analyses were performed using chi-square test, ANOVA, Kruskal-Wallis test, and logistic regression models. Differences in the studied variables were small, but proxy respondents were slightly more likely to have missing data than the new mothers. Differences and missing data were more common for the use of prenatal care and outcome variables (mode of delivery, place of delivery, birth weight, use of postnatal care, and gestational age at birth) than for the background characteristics of the participants. Husbands' reports were closer to the index reports than that of the other proxies. The associations between the exposures and outcomes were mostly similar between the proxy and index respondents. Relatives can be interviewed instead of women to study prenatal care without a substantial negative impact on study results. Studies using proxy respondents should stratify the analysis by type of respondents.

  16. An Efficient Identity-Based Proxy Blind Signature for Semioffline Services

    Directory of Open Access Journals (Sweden)

    Hongfei Zhu

    2018-01-01

    Full Text Available Fog computing extends the cloud computing to the network edge and allows deploying a new type of semioffline services, which can provide real-time transactions between two entities, while the central cloud server is offline and network edge devices are online. For an e-payment system and e-voting with such feature, proxy blind signature is a cornerstone to protect users’ privacy. However, the signature based on number theorem, such as hard mathematical problems on factoring problem, discrete logarithm problem, and bilinear pairings, cannot defeat quantum computers attack. Meanwhile, these schemes need to depend on complex public key infrastructure. Thus, we construct an identity-based proxy blind signature scheme based on number theorem research unit lattice, which can defeat quantum computers attack and does not need to depend on public key infrastructure. The security of the proposed scheme is dependent on Ring-Small Integer Solution problem over number theorem research unit lattice. The proposed scheme meets the properties of blind signature and proxy signature. Then we compare the proposed scheme with other existing proxy blind signature schemes; the result shows that the proposed scheme outperforms ZM scheme except in proxy signer’s signature size and can be more secure than TA scheme and MMHP scheme.

  17. Shifty: A Weight-Shifting Dynamic Passive Haptic Proxy to Enhance Object Perception in Virtual Reality.

    Science.gov (United States)

    Zenner, Andre; Kruger, Antonio

    2017-04-01

    We define the concept of Dynamic Passive Haptic Feedback (DPHF) for virtual reality by introducing the weight-shifting physical DPHF proxy object Shifty. This concept combines actuators known from active haptics and physical proxies known from passive haptics to construct proxies that automatically adapt their passive haptic feedback. We describe the concept behind our ungrounded weight-shifting DPHF proxy Shifty and the implementation of our prototype. We then investigate how Shifty can, by automatically changing its internal weight distribution, enhance the user's perception of virtual objects interacted with in two experiments. In a first experiment, we show that Shifty can enhance the perception of virtual objects changing in shape, especially in length and thickness. Here, Shifty was shown to increase the user's fun and perceived realism significantly, compared to an equivalent passive haptic proxy. In a second experiment, Shifty is used to pick up virtual objects of different virtual weights. The results show that Shifty enhances the perception of weight and thus the perceived realism by adapting its kinesthetic feedback to the picked-up virtual object. In the same experiment, we additionally show that specific combinations of haptic, visual and auditory feedback during the pick-up interaction help to compensate for visual-haptic mismatch perceived during the shifting process.

  18. Foraminifera Models to Interrogate Ostensible Proxy-Model Discrepancies During Late Pliocene

    Science.gov (United States)

    Jacobs, P.; Dowsett, H. J.; de Mutsert, K.

    2017-12-01

    Planktic foraminifera faunal assemblages have been used in the reconstruction of past oceanic states (e.g. the Last Glacial Maximum, the mid-Piacenzian Warm Period). However these reconstruction efforts have typically relied on inverse modeling using transfer functions or the modern analog technique, which by design seek to translate foraminifera into one or two target oceanic variables, primarily sea surface temperature (SST). These reconstructed SST data have then been used to test the performance of climate models, and discrepancies have been attributed to shortcomings in climate model processes and/or boundary conditions. More recently forward proxy models or proxy system models have been used to leverage the multivariate nature of proxy relationships to their environment, and to "bring models into proxy space". Here we construct ecological models of key planktic foraminifera taxa, calibrated and validated with World Ocean Atlas (WO13) oceanographic data. Multiple modeling methods (e.g. multilayer perceptron neural networks, Mahalanobis distance, logistic regression, and maximum entropy) are investigated to ensure robust results. The resulting models are then driven by a Late Pliocene climate model simulation with biogeochemical as well as temperature variables. Similarities and differences with previous model-proxy comparisons (e.g. PlioMIP) are discussed.

  19. Mg/Ca and Sr/Ca as novel geochemical proxies for understanding sediment transport processes within coral reefs

    Science.gov (United States)

    Gacutan, J.; Vila-Concejo, A.; Nothdurft, L. D.; Fellowes, T. E.; Cathey, H. E.; Opdyke, B. N.; Harris, D. L.; Hamylton, S.; Carvalho, R. C.; Byrne, M.; Webster, J. M.

    2017-10-01

    appendages results in a decrease in Mg/Ca. BSE imaging and WDS elemental mapping provided evidence for cementation, facilitated by microbial-boring as the primary cause of increasing Sr/Ca. These novel proxies hold advantages over taphonomic measures and further provide a rapid method to infer sediment transport pathways within back-reef environments.

  20. A Strategy for a Parametric Flood Insurance Using Proxies

    Science.gov (United States)

    Haraguchi, M.; Lall, U.

    2017-12-01

    Traditionally, the design of flood control infrastructure and flood plain zoning require the estimation of return periods, which have been calculated by river hydraulic models with rainfall-runoff models. However, this multi-step modeling process leads to significant uncertainty to assess inundation. In addition, land use change and changing climate alter the potential losses, as well as make the modeling results obsolete. For these reasons, there is a strong need to create parametric indexes for the financial risk transfer for large flood events, to enable rapid response and recovery. Hence, this study examines the possibility of developing a parametric flood index at the national or regional level in Asia, which can be quickly mobilized after catastrophic floods. Specifically, we compare a single trigger based on rainfall index with multiple triggers using rainfall and streamflow indices by conducting case studies in Bangladesh and Thailand. The proposed methodology is 1) selecting suitable indices of rainfall and streamflow (if available), 2) identifying trigger levels for specified return periods for losses using stepwise and logistic regressions, 3) measuring the performance of indices, and 4) deriving return periods of selected windows and trigger levels. Based on the methodology, actual trigger levels were identified for Bangladesh and Thailand. Models based on multiple triggers reduced basis risks, an inherent problem in an index insurance. The proposed parametric flood index can be applied to countries with similar geographic and meteorological characteristics, and serve as a promising method for ex-ante risk financing for developing countries. This work is intended to be a preliminary work supporting future work on pricing risk transfer mechanisms in ex-ante risk finance.

  1. 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.

  2. Role of Advance Care Planning in Proxy Decision Making Among Individuals With Dementia and Their Family Caregivers.

    Science.gov (United States)

    Kwak, Jung; De Larwelle, Jessica A; Valuch, Katharine O'Connell; Kesler, Toni

    2016-01-01

    Health care proxies make important end-of-life decisions for individuals with dementia. A cross-sectional survey was conducted to examine the role of advance care planning in proxy decision making for 141 individuals with cognitive impairment, Alzheimer's disease, or other types of dementia. Proxies who did not know the preferences of individuals with dementia for life support treatments reported greater understanding of their values. Proxies of individuals with dementia who did not want life support treatments anticipated receiving less support and were more uncertain in decision making. The greater knowledge proxies had about dementia trajectory, family support, and trust of physicians, the more informed, clearer, and less uncertain they were in decision making. In addition to advance care planning, multiple factors influence proxy decision making, which should be considered in developing interventions and future research to support informed decision making for individuals with dementia and their families. Copyright 2016, SLACK Incorporated.

  3. 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

  4. Methodological Considerations in Couples' Fertility Intentions: Missing Men and the Viability of Women's Proxy Reports.

    Science.gov (United States)

    Stykes, J Bart

    2018-02-19

    Introduction Recent efforts show potential to advance research on unintended childbearing by taking a couple-level approach. However, this work has neither adequately addressed methodological concerns stemming from the challenges associated with male fertility data nor considered the viability of women's proxy reports of fathers intentions. Methods Data from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) were used to assess the implications of low response rates among men on couples' unintended childbearing. Then, the accuracy of women's proxy reports of fathers intentions was assessed. Weighted logistic regression analyses were conducted to determine how women's characteristics were associated with men's survey participation whereas weighted multinomial logistic regression analyses were applied to determine how women's characteristics were linked with the accuracy of her proxy report. Results Almost half (46%) of women cannot be matched with data from the child's father, and this discrepancy is most problematic for women who are black, foreign-born, less educated, and unmarried at birth. Women's proxy reports appear viable as 75% of women's reports are consistent with men's responses. Yet, proxy reports underestimate disagreement in couples' intentions as mothers who intended the birth are at an increased risk of "inaccurately" reporting that fathers share their intentions. Discussion Direct approaches to couples' intentions yield privileged samples and systematically omit women at the greatest risk of an unintended birth. However, proxies underestimate disagreement in couples' intentions-a key contribution to the couple approach. Accordingly each approach has its own merits which must be considered in light of specified research questions.

  5. 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.

  6. A proxy for variance in dense matching over homogeneous terrain

    Science.gov (United States)

    Altena, Bas; Cockx, Liesbet; Goedemé, Toon

    2014-05-01

    Automation in photogrammetry and avionics have brought highly autonomous UAV mapping solutions on the market. These systems have great potential for geophysical research, due to their mobility and simplicity of work. Flight planning can be done on site and orientation parameters are estimated automatically. However, one major drawback is still present: if contrast is lacking, stereoscopy fails. Consequently, topographic information cannot be obtained precisely through photogrammetry for areas with low contrast. Even though more robustness is added in the estimation through multi-view geometry, a precise product is still lacking. For the greater part, interpolation is applied over these regions, where the estimation is constrained by uniqueness, its epipolar line and smoothness. Consequently, digital surface models are generated with an estimate of the topography, without holes but also without an indication of its variance. Every dense matching algorithm is based on a similarity measure. Our methodology uses this property to support the idea that if only noise is present, no correspondence can be detected. Therefore, the noise level is estimated in respect to the intensity signal of the topography (SNR) and this ratio serves as a quality indicator for the automatically generated product. To demonstrate this variance indicator, two different case studies were elaborated. The first study is situated at an open sand mine near the village of Kiezegem, Belgium. Two different UAV systems flew over the site. One system had automatic intensity regulation, and resulted in low contrast over the sandy interior of the mine. That dataset was used to identify the weak estimations of the topography and was compared with the data from the other UAV flight. In the second study a flight campaign with the X100 system was conducted along the coast near Wenduine, Belgium. The obtained images were processed through structure-from-motion software. Although the beach had a very low

  7. 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.

  8. 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

  9. PROXY-BASED PATCHING STREAM TRANSMISSION STRATEGY IN MOBILE STREAMING MEDIA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Liao Jianxin; Lei Zhengxiong; Ma Xutao; Zhu Xiaomin

    2006-01-01

    A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strategy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA) network. Performance of the whole system can be improved by using patching stream to transmit anterior part of the suffix that had been played back, and by batching all the demands for the suffix arrived in prefix period and patching stream transmission threshold period. Experimental results show that this strategy can efficiently reduce average network transmission cost and number of channels consumed in central streaming media server.

  10. 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.

  11. On the construction of a time base and the elimination of averaging errors in proxy records

    Science.gov (United States)

    Beelaerts, V.; De Ridder, F.; Bauwens, M.; Schmitz, N.; Pintelon, R.

    2009-04-01

    Proxies are sources of climate information which are stored in natural archives (e.g. ice-cores, sediment layers on ocean floors and animals with calcareous marine skeletons). Measuring these proxies produces very short records and mostly involves sampling solid substrates, which is subject to the following two problems: Problem 1: Natural archives are equidistantly sampled at a distance grid along their accretion axis. Starting from these distance series, a time series needs to be constructed, as comparison of different data records is only meaningful on a time grid. The time series will be non-equidistant, as the accretion rate is non-constant. Problem 2: A typical example of sampling solid substrates is drilling. Because of the dimensions of the drill, the holes drilled will not be infinitesimally small. Consequently, samples are not taken at a point in distance, but rather over a volume in distance. This holds for most sampling methods in solid substrates. As a consequence, when the continuous proxy signal is sampled, it will be averaged over the volume of the sample, resulting in an underestimation of the amplitude. Whether this averaging effect is significant, depends on the volume of the sample and the variations of interest of the proxy signal. Starting from the measured signal, the continuous signal needs to be reconstructed in order eliminate these averaging errors. The aim is to provide an efficient identification algorithm to identify the non-linearities in the distance-time relationship, called time base distortions, and to correct for the averaging effects. Because this is a parametric method, an assumption about the proxy signal needs to be made: the proxy record on a time base is assumed to be harmonic, this is an obvious assumption because natural archives often exhibit a seasonal cycle. In a first approach the averaging effects are assumed to be in one direction only, i.e. the direction of the axis on which the measurements were performed. The

  12. Does the subjective quality of life of children with specific learning disabilities (SpLD) agree with their parents' proxy reports?

    Science.gov (United States)

    Rotsika, V; Coccossis, M; Vlassopoulos, M; Papaeleftheriou, E; Sakellariou, K; Anagnostopoulos, D C; Kokkevi, A; Skevington, S

    2011-10-01

    /her relationships with peers. In the control group, agreement between children and parents seems to be more even and evident. Proxy assessments in children with SpLD and their parents may be useful for planning targeted support interventions for these families.

  13. Determining ancestry proportions in complex admixture scenarios in South Africa using a novel proxy ancestry selection method.

    Directory of Open Access Journals (Sweden)

    Emile R Chimusa

    Full Text Available Admixed populations can make an important contribution to the discovery of disease susceptibility genes if the parental populations exhibit substantial variation in susceptibility. Admixture mapping has been used successfully, but is not designed to cope with populations that have more than two or three ancestral populations. The inference of admixture proportions and local ancestry and the imputation of missing genotypes in admixed populations are crucial in both understanding variation in disease and identifying novel disease loci. These inferences make use of reference populations, and accuracy depends on the choice of ancestral populations. Using an insufficient or inaccurate ancestral panel can result in erroneously inferred ancestry and affect the detection power of GWAS and meta-analysis when using imputation. Current algorithms are inadequate for multi-way admixed populations. To address these challenges we developed PROXYANC, an approach to select the best proxy ancestral populations. From the simulation of a multi-way admixed population we demonstrate the capability and accuracy of PROXYANC and illustrate the importance of the choice of ancestry in both estimating admixture proportions and imputing missing genotypes. We applied this approach to a complex, uniquely admixed South African population. Using genome-wide SNP data from over 764 individuals, we accurately estimate the genetic contributions from the best ancestral populations: isiXhosa [Formula: see text], ‡Khomani SAN [Formula: see text], European [Formula: see text], Indian [Formula: see text], and Chinese [Formula: see text]. We also demonstrate that the ancestral allele frequency differences correlate with increased linkage disequilibrium in the South African population, which originates from admixture events rather than population bottlenecks.The collective term for people of mixed ancestry in southern Africa is "Coloured," and this is officially recognized in South

  14. 17 CFR 240.14a-5 - Presentation of information in proxy statement.

    Science.gov (United States)

    2010-04-01

    ... to printed documents, such as type size and font, by presenting all required information in a format... information. (d)(1) All printed proxy statements shall be in roman type at least as large and as legible as 10-point modern type, except that to the extent necessary for convenient presentation financial statements...

  15. Quercus macrocarpa annual, early- and latewood widths as hydroclimatic proxies, southeastern Saskatchewan, Canada

    International Nuclear Information System (INIS)

    Vanstone, Jessica R; Sauchyn, David J

    2010-01-01

    Fluctuations in size of annual ring-widths of Quercus species suggest that environmental factors influence the size and density of vessels within the ring, either by acting as a limiting factor for growth or through fine tuning of the wood structure to environmental factors. The purpose of this study is to assess the potential of Q. macrocarpa to provide multiple dendroclimatic proxies for the Canadian Prairies, by investigating growth responses of annual, early- and latewood widths to regional climate variability. Results indicate that ring width chronologies, from southeastern Saskatchewan capture regional signals related to moisture and drought conditions. Correlations suggest that late-wood widths are more representative of annual ring-widths, than are early-wood widths, and are the best proxy of seasonal fluctuations in climate. Thus regression models that include latewood widths were able to account for more variance in the Palmer Drought Severity Index (PDSI) than when annual ring-widths are used as the only proxy. This study demonstrates that Q. macrocarpa can provide multiple dendroclimatic proxies for investigating large scale climatic fluctuations at annual and sub-annual time scales. It is novel in terms of sub-annual analysis of tree-rings in a region that previously lacked dendrochronological research.

  16. Calibration and application of the branched GDGT temperature proxy on East African lake sediments

    NARCIS (Netherlands)

    Loomis, S.E.; Russell, J.M.; Ladd, B.; Street-Perrott, F.A.; Sinninghe Damsté, J.S.

    2012-01-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a novel proxy for mean annual air temperature (MAAT) and have the potential to be broadly applicable to climate reconstruction using lacustrine sediments. Several calibrations have been put forth relating brGDGT distributions to MAAT using

  17. Calibration and application of the branched GDGT proxy on East African lake sediments

    NARCIS (Netherlands)

    Loomis, S.E.; Russell, J.M.; Ladd, B.; Street-Perrott, F.A.; Sinninghe Damsté, J.S.

    2012-01-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a novel proxy for mean annual air temperature (MAAT) and have the potential to be broadly applicable to climate reconstruction using lacustrine sediments. Several calibrations have been put forth relating brGDGT distributions to MAAT using

  18. 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…

  19. TEX₈₆ paleothermometry : proxy validation and application in marine sediments

    NARCIS (Netherlands)

    Huguet, Carme

    2007-01-01

    Determination of past sea surface temperature (SST) is of primary importance for the reconstruction of natural climatic changes, modelling of climate and reconstruction of ocean circulation. Recently, a new SST proxy was introduced, the TetraEther indeX of lipids with 86 carbons (TEX₈₆), which is

  20. Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar

    NARCIS (Netherlands)

    Grove, C.A.; Zinke, J.; Scheufen, T.; Maina, J.; Epping, E.; Boer, W.; Randriamanantsoa, B.; Brummer, G.-J.A.

    2012-01-01

    Coral cores provide vital climate reconstructions for site-specific temporal variability in river flow and sediment load. Yet, their ability to record spatial differences across multiple catchments is relatively unknown. Here, we investigate spatial linkages between four coral proxies of terrestrial

  1. 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.

  2. [Analysis of prevalence of self-reported hearing loss and associated factors: primary versus proxy informant].

    Science.gov (United States)

    Quevedo, André Luis Alves de; Leotti, Vanessa Bielefeldt; Goulart, Bárbara Niegia Garcia de

    2017-07-03

    The objective was to evaluate differences between prevalence rates for self-reported hearing loss and associated factors, obtained from responses by primary and proxy informants in a Population-Based Study on Human Communication Disorders (DCH-POP in Portuguese). This was a study on epidemiological methods using data from a cross-sectional household survey with a sample of 1,253 individuals from Southern Brazil. To verify differences between prevalence rates comparing primary informants and proxy informants, we used the chi-square or Fisher's exact test for categorical variables and Mann-Whitney for continuous variables. The log-binomial model was adjusted for hearing loss as the dependent variable, considering three datasets: the entire sample, only primary informants, and only proxy informants, estimating association by prevalence ratios. In the final models, only the independent variables age and dizziness were associated with hearing loss, independently of the dataset that was used. Proxy informants generally underestimated the prevalence rates for the target outcomes, when compared to primary informants.

  3. Long-chain alkaenone unsaturation index as sea surface temperature proxy in southwest Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, N.S.; Pasha, S.K.G.; SriRamKrishna, M.; Shirodkar, P.V.; Yadava, M.G.; Rao, K.M.

    As a proxy of the sea surface temperature (SST), C sub(37) long-chain alkenones (LCAs) preserved in sediments of the southwestern Bay of Bengal and dating back to the last glacial period, were identified in SIM GC-EI MS spectra run at m/z 530...

  4. 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.

  5. 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.

  6. Atmospheric multidecadal variations in the North Atlantic realm: proxy data, observations, and atmospheric circulation model studies

    Directory of Open Access Journals (Sweden)

    K. Grosfeld

    2007-01-01

    Full Text Available We investigate the spatial and temporal characteristics of multidecadal climate variability in the North Atlantic realm, using observational data, proxy data and model results. The dominant pattern of multidecadal variability of SST depicts a monopolar structure in the North Atlantic during the instrumental period with cold (warm phases during 1900–1925 and 1970–1990 (1870–1890 and 1940–1960. Two atmospheric general circulation models of different complexity forced with global SST over the last century show SLP anomaly patterns from the warm and cold phases of the North Atlantic similar to the corresponding observed patterns. The analysis of a sediment core from Cariaco Basin, a coral record from the northern Red Sea, and a long-term sea level pressure (SLP reconstruction reveals that the multidecadal mode of the atmospheric circulation characterizes climate variability also in the pre-industrial era. The analyses of SLP reconstruction and proxy data depict a persistent atmospheric mode at least over the last 300 years, where SLP shows a dipolar structure in response to monopolar North Atlantic SST, in a similar way as the models' responses do. The combined analysis of observational and proxy data with model experiments provides an understanding of multidecadal climate modes during the late Holocene. The related patterns are useful for the interpretation of proxy data in the North Atlantic realm.

  7. The use of Sphagnum cellulose oxygen isotope ratios in ombrotrophic peatlands as a proxy for paleoclimate.

    Science.gov (United States)

    Taylor, M.; Pendall, E.; Jackson, S.; Booth, R. K.; Nichols, J. E.; Huang, Y.

    2006-12-01

    Developing proxies for discerning paleoclimate that are independent of the pollen record can provide insight into various aspects of climate variability and improve confidence in the interpretation of climate-vegetation interactions. To date, proxies including plant macrofossils, humification indices, testate amoebae, and ratios of n-alkane abundances have been used to infer past climate variability from temperate ombrotrophic peatlands in upper Midwestern North America. These proxies are used to infer past changes in surface-moisture conditions, which in ombrotrophic peatlands is primarily a function of precipitation and temperature. This study investigates the potential uses of stable oxygen isotopes to complement hydrologic proxies. δ18O of surface water and Sphagnum moss cellulose from bogs throughout North America indicates a correlation between average growing season temperatures and δ18O-values. The existence of a modern temperature signal in moss cellulose suggests that δ18O-derived records will not only complement paleohydrological records, but also help assess relative changes in precipitation and temperature. Humification and testate amoebae data from two cores taken from Minden and Irwin Smith Bogs in central and northeastern Michigan have recorded several extreme drought events during the Holocene, including one at 1000 YBP. Comparison of δ18O-values of picked Sphagnum remains to down-core humification and testate amoebae data suggest good temporal correspondence, with the δ18O-values around 1000 YBP indicating a warmer growing season.

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

    NARCIS (Netherlands)

    Porter, T.J.; Froese, D.G.; Feakins, S.J.; Bindeman, I.N.; Mahony, M.E.; Pautler, B.G.; Reichart, G.-J.; Sanborn, P.T.; Simpson, M.J.; Weijers, J.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

  9. 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…

  10. Indian monsoon variability at different time scales: Marine and terrestrial proxy records

    Digital Repository Service at National Institute of Oceanography (India)

    Patnaik, R.; Gupta, A; Naidu, P.D.; Yadav, R.R.; Bhattacharyya, A; Kumar, M.

    Here, we present a review of the work done in India during 2007-2011 on various proxy records of monsoon variability preserved in the marine (Central Indian Basin, western, northern and eastern Arabian Sea and the Bay of Bengal) and terrestrial...

  11. Governance characteristics and the market reaction to the SEC’s proxy access rule

    NARCIS (Netherlands)

    Akyol, A.; Lim, B.; Verwijmeren, P.

    2012-01-01

    We examine the wealth effects of the Security and Exchange Commission's (SEC) recent proxy access rule to facilitate director nominations by shareholders. We focus on how a firm's governance characteristics affect the market reaction to the rule. We find more negative announcement effects for firms

  12. 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

  13. Subjective Fatigue in Children with Hearing Loss Assessed Using Self- and Parent-Proxy Report

    Science.gov (United States)

    Hornsby, Benjamin W. Y.; Gustafson, Samantha J.; Lancaster, Hope; Cho, Sun-Joo; Camarata, Stephen; Bess, Fred H.

    2017-01-01

    Purpose: The primary purposes of this study were to examine the effects of hearing loss and respondent type (self- vs. parent-proxy report) on subjective fatigue in children. We also examined associations between child-specific factors and fatigue ratings. Method: Subjective fatigue was assessed using the Pediatric Quality of Life Inventory…

  14. 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.

  15. 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.

  16. Graphite-(Mo,W)S2 intergrowth as a palaeoenvironmental proxy in metasedimentary rocks

    Science.gov (United States)

    Cabral, Alexandre Raphael; Zeh, Armin; da Silva Viana, Nívea Cristina; Schirmer, Thomas; Lehmann, Bernd

    2017-12-01

    Molybdenum enrichment in pristine organic-C-rich sedimentary rocks forms the basis for inferring the presence of dissolved oxygen in seawater. Organic matter removes dissolved hexavalent Mo from seawater where anoxic and euxinic conditions are attained. However, it is unknown whether this Mo-based proxy is retained under metamorphic conditions where organic C is no longer preserved. Here, we describe aggregates of graphite and molybdenite (MoS2) containing up to 21 mass per cent of W as tungstenite (WS2) in solid solution. These aggregates are disseminated in a sulfide-rich Mn-silicate-carbonate rock (queluzite), metamorphosed under amphibolite-facies conditions within the Archaean Barbacena greenstone belt in Minas Gerais, Brazil. Our finding indicates that: (i) W is, like Mo, a palaeoenvironmental proxy; (ii) the W proxy is sensitive to high fS2/fO2 environments; (iii) both Mo and W proxies survive amphibolite-facies overprint as (Mo,W)S2 intergrown with graphite. Archaean greenstones are potential candidates for storing palaeoenvironmental information as (Mo,W)S2-graphite intergrowths.

  17. 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…

  18. 17 CFR 240.14a-16 - Internet availability of proxy materials.

    Science.gov (United States)

    2010-04-01

    ... effect the corporate action, and complying with all other requirements of this section. (2) Unless the... the communication is not a form for voting and presents only an overview of the more complete proxy... receive a paper or e-mail copy; (5) The date, time, and location of the meeting, or if corporate action is...

  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. Development of the Wintertime Sr/Ca-SST Record from Red Sea Corals as a Proxy for the North Atlantic Oscillation

    Science.gov (United States)

    Bernstein, W. N.; Hughen, K. A.

    2009-12-01

    -weekly temporal resolution for downcore SST reconstructions over the past 140 years, which will be used to evaluate the ability of the coral proxies to capture instrumental NAO variability. We expect that this winter Sr/Ca record will exhibit coherence with the NAO similar to that evident between Red Sea instrumental SST and the NAO index. Future work will involve construction of an NAO record back ~400 years, using the multi-core Sr/Ca-SST calibration applied to a combination of new records from modern and fossil coral material. This record will be examined to identify changes in NAO behavior as a function of frequency, and to compare frequency-dependent NAO variability between periods of relatively warm and cold hemispheric climate. This analysis will allow us to test the hypothesized link between NAO behavior and mean climate conditions, and if confirmed, improve predictions regarding the role of the NAO in impending climate change. References Hurrell, J. et al., 2003, in The North Atlantic Oscillation: Climatic Significance and Environmental Impact, 1-36 (A.G.U., Washington, D.C.). Visbeck, M. et al., 2001, Proc. Nat. Acad. Sci. 98, 12876-12877.

  1. Assessment of the Coral Temperature Proxies for Orbicella faveolata in the Southwestern Gulf of Mexico

    Science.gov (United States)

    Vara, M. A.; DeLong, K. L.; Herrmann, A. D.; Ouellette, G., Jr.; Richey, J. N.

    2017-12-01

    Coral Sr/Ca is a robust proxy of sea surface temperature (SST); however, discrepancies in the Sr/Ca-SST relationship among colonies of the same species may reduce confidence in absolute temperature reconstructions. Furthermore, terrestrial carbonate weathering can provide local sources of Sr and/or Ca to coastal waters that may disrupt the temperature-based coral Sr/Ca signal. Thus other trace metal SST proxies have been suggested to circumvent these issues (Li/Ca, Li/Mg, and Sr-U). Coral Ba/Ca has been used as a proxy for runoff and coastal upwelling, and therefore may be used to identify intervals when these processes overprint the Sr/Ca-SST signal. This study tests multiple coral SST proxies using reproducibility assessments to determine the best performing SST proxy. We conduct these assessments with cores recovered in 1991 by the U.S. Geological Survey from five Orbicella faveolata colonies from three reefs offshore of Veracruz, Mexico (19.06°N, 96.93°W) in water depths varying from 3 to 12 m. Previous studies found micromilling the complex skeletal structure of O. faveolata challenging and that monthly resolution may not recover full seasonal cycles. We use a laser ablation inductively coupled plasma mass spectrometer to simultaneously sample this coral's structure at weekly intervals spanning 8 years for Li/Ca, Li/Mg, Sr-U, Sr/Ca, and Ba/Ca. Here we found coral Li/Ca means and seasonal variations are similar among colonies thus this proxy may capture absolute temperature and SST variability. Similar to previous research with Porites corals, Li/Ca in these O. faveolata corals decreases with increases in SST with similar slopes and intercepts. During the last 10 years of these corals' lives, coral Sr/Ca analysis reveals a mean shift among colonies suggesting an external source could have disrupted the Sr/Ca signal, possibly seasonal runoff and/or winter upwelling common to Veracruz waters. Coral Ba/Ca analyses reveals elevated values in winters that coincide

  2. Representativeness of single lidar stations for zonally averaged ozone profiles, their trends and attribution to proxies

    Directory of Open Access Journals (Sweden)

    C. Zerefos

    2018-05-01

    Full Text Available This paper is focusing on the representativeness of single lidar stations for zonally averaged ozone profile variations over the middle and upper stratosphere. From the lower to the upper stratosphere, ozone profiles from single or grouped lidar stations correlate well with zonal means calculated from the Solar Backscatter Ultraviolet Radiometer (SBUV satellite overpasses. The best representativeness with significant correlation coefficients is found within ±15° of latitude circles north or south of any lidar station. This paper also includes a multivariate linear regression (MLR analysis on the relative importance of proxy time series for explaining variations in the vertical ozone profiles. Studied proxies represent variability due to influences outside of the earth system (solar cycle and within the earth system, i.e. dynamic processes (the Quasi Biennial Oscillation, QBO; the Arctic Oscillation, AO; the Antarctic Oscillation, AAO; the El Niño Southern Oscillation, ENSO, those due to volcanic aerosol (aerosol optical depth, AOD, tropopause height changes (including global warming and those influences due to anthropogenic contributions to atmospheric chemistry (equivalent effective stratospheric chlorine, EESC. Ozone trends are estimated, with and without removal of proxies, from the total available 1980 to 2015 SBUV record. Except for the chemistry related proxy (EESC and its orthogonal function, the removal of the other proxies does not alter the significance of the estimated long-term trends. At heights above 15 hPa an inflection point between 1997 and 1999 marks the end of significant negative ozone trends, followed by a recent period between 1998 and 2015 with positive ozone trends. At heights between 15 and 40 hPa the pre-1998 negative ozone trends tend to become less significant as we move towards 2015, below which the lower stratosphere ozone decline continues in agreement with findings of recent literature.

  3. Deuterium Values from Hydrated Volcanic Glass: A Paleoelevation Proxy for Oregon's Cascade Range

    Science.gov (United States)

    Carlson, T. B.; Bershaw, J. T.; Cassel, E. J.

    2017-12-01

    Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct Cenozoic paleoenvironments. However, the reliability and proper sample preparation protocol have been debated. The Cascades are an excellent location to study the validity of hydrated volcanic glass as a paleoelevation proxy for several reasons. Moisture is largely 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). Additionally, past studies have inferred uplift of the Cascades since the Miocene based on changing fossil assemblages, tectonic models, and other isotopic proxies including soil carbonates and fossil teeth. In this study, hydrated volcanic ash samples from the lee of the Cascades were rinsed with hydrochloric acid and sonicated before glass shards were hand-selected and analyzed for δD and wt. % water. These preliminary results exhibited δD values becoming enriched with time, a trend opposite of other paleowater proxy studies in the area. A possible explanation for this trend is contamination due to inadequate removal of materials adhered to shard surfaces that can readily exchange with environmental water. Recent research asserts that hydrofluoric acid (HF) etching during sample preparation is necessary to accurately measure δD values of syndepositional water. Volcanic ash samples were reanalyzed after preparation using HF abrasion and heavy liquid separation. The data from these two subsets are interpreted in the context of modern water across the range, as well as other paleowater proxy and geologic studies to determine the implications of volcanic glass as a paleoelevation proxy in the Pacific Northwest.

  4. 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.

  5. Representativeness of single lidar stations for zonally averaged ozone profiles, their trends and attribution to proxies

    Science.gov (United States)

    Zerefos, Christos; Kapsomenakis, John; Eleftheratos, Kostas; Tourpali, Kleareti; Petropavlovskikh, Irina; Hubert, Daan; Godin-Beekmann, Sophie; Steinbrecht, Wolfgang; Frith, Stacey; Sofieva, Viktoria; Hassler, Birgit

    2018-05-01

    This paper is focusing on the representativeness of single lidar stations for zonally averaged ozone profile variations over the middle and upper stratosphere. From the lower to the upper stratosphere, ozone profiles from single or grouped lidar stations correlate well with zonal means calculated from the Solar Backscatter Ultraviolet Radiometer (SBUV) satellite overpasses. The best representativeness with significant correlation coefficients is found within ±15° of latitude circles north or south of any lidar station. This paper also includes a multivariate linear regression (MLR) analysis on the relative importance of proxy time series for explaining variations in the vertical ozone profiles. Studied proxies represent variability due to influences outside of the earth system (solar cycle) and within the earth system, i.e. dynamic processes (the Quasi Biennial Oscillation, QBO; the Arctic Oscillation, AO; the Antarctic Oscillation, AAO; the El Niño Southern Oscillation, ENSO), those due to volcanic aerosol (aerosol optical depth, AOD), tropopause height changes (including global warming) and those influences due to anthropogenic contributions to atmospheric chemistry (equivalent effective stratospheric chlorine, EESC). Ozone trends are estimated, with and without removal of proxies, from the total available 1980 to 2015 SBUV record. Except for the chemistry related proxy (EESC) and its orthogonal function, the removal of the other proxies does not alter the significance of the estimated long-term trends. At heights above 15 hPa an inflection point between 1997 and 1999 marks the end of significant negative ozone trends, followed by a recent period between 1998 and 2015 with positive ozone trends. At heights between 15 and 40 hPa the pre-1998 negative ozone trends tend to become less significant as we move towards 2015, below which the lower stratosphere ozone decline continues in agreement with findings of recent literature.

  6. Investigating the consistency between proxy-based reconstructions and climate models using data assimilation: a mid-Holocene case study

    NARCIS (Netherlands)

    A. Mairesse; H. Goosse; P. Mathiot; H. Wanner; S. Dubinkina (Svetlana)

    2013-01-01

    htmlabstractThe mid-Holocene (6 kyr BP; thousand years before present) is a key period to study the consistency between model results and proxy-based reconstruction data as it corresponds to a standard test for models and a reasonable number of proxy-based records is available. Taking advantage of

  7. Using paleoclimate proxy-data to select an optimal realisation in an ensemble of simulations of the past millennium.

    NARCIS (Netherlands)

    Goosse, H.; Renssen, H.; Timmermann, A.; Bradley, R.S.; Mann, M.E.

    2006-01-01

    We present and describe in detail the advantages and limitations of a technique that combines in an optimal way model results and proxy-data time series in order to obtain states of the climate system consistent with model physics, reconstruction of past radiative forcing and proxy records. To

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

    Science.gov (United States)

    Guo, Yuzhu; Storm, Fabio; Zhao, Yifan; Billings, Stephen A; Pavic, Aleksandar; Mazzà, Claudia; Guo, Ling-Zhong

    2017-09-22

    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.

  9. Proxying UPnP service discovery and access to a non-IP Bluetooth network on a mobile phone

    NARCIS (Netherlands)

    Delphinanto, A.; Koonen, A.M.J.; Hartog, den F.T.H.; Peeters, M.E.

    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 and

  10. Multiple imputation using linked proxy outcome data resulted in important bias reduction and efficiency gains: a simulation study.

    Science.gov (United States)

    Cornish, R P; Macleod, J; Carpenter, J R; Tilling, K

    2017-01-01

    When an outcome variable is missing not at random (MNAR: probability of missingness depends on outcome values), estimates of the effect of an exposure on this outcome are often biased. We investigated the extent of this bias and examined whether the bias can be reduced through incorporating proxy outcomes obtained through linkage to administrative data as auxiliary variables in multiple imputation (MI). Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) we estimated the association between breastfeeding and IQ (continuous outcome), incorporating linked attainment data (proxies for IQ) as auxiliary variables in MI models. Simulation studies explored the impact of varying the proportion of missing data (from 20 to 80%), the correlation between the outcome and its proxy (0.1-0.9), the strength of the missing data mechanism, and having a proxy variable that was incomplete. Incorporating a linked proxy for the missing outcome as an auxiliary variable reduced bias and increased efficiency in all scenarios, even when 80% of the outcome was missing. Using an incomplete proxy was similarly beneficial. High correlations (> 0.5) between the outcome and its proxy substantially reduced the missing information. Consistent with this, ALSPAC analysis showed inclusion of a proxy reduced bias and improved efficiency. Gains with additional proxies were modest. In longitudinal studies with loss to follow-up, incorporating proxies for this study outcome obtained via linkage to external sources of data as auxiliary variables in MI models can give practically important bias reduction and efficiency gains when the study outcome is MNAR.

  11. Multi-proxy approach for palaeoclimate reconstruction using a loess-palaeosol sequence from Süttő , Hungary

    Science.gov (United States)

    Thiel, Christine; Königer, Paul; Ostertag-Henning, Christian; Scheeder, Georg; Novothny, Ágnes; Horváth, Erzsébet; Wacha, Lara; Techmer, Astrid; Frechen, Manfred

    2010-05-01

    The loess-palaeosol sequence at Süttő , Hungary contains a high-resolution terrestrial archive of palaeoenvironmental changes. The sequence is about 20 m thick and overlies travertine which was dated using Uranium-series to 235-314 ka (Sierralta et al., in press). Imbedded with the loess are two greyish stratified horizons, three brownish steppe-like soils and a pedocomplex composed of a reddish-brown palaeosol covered by a chernozem. Detailed dating studies were carried out (Novothny et al, 2009, Novothny et al., in press) revealing more or less continuous sedimentation from marine isotope stage (MIS) 6 to MIS 2. High-resolution grain size and magnetic susceptibility data exist (Novothny et al., in prep.) which allow for palaeoenvironmental reconstructions. In addition to those data sets we analysed the carbon and oxygen isotopic composition of bulk carbonate, carbonate nodules, and organic material in order to get further insight into palaeoprecipitation and palaeoclimatic conditions. To strengthen the interpretation based on isotopic data, we examined biomarkers derived from land plants (long-chain n-alkanes) for both loess and palaeosols to add information on the vegetation changes. We will discuss the new results in comparison with the published data sets and highlight inherent problems of the individual approaches. Novothny, A., Frechen, M., Horváth, E., Wacha, L., Rolf, C., in prep. High resolution grain size and magnetic susceptibility record of the last glacial cycles in the Süttő loess section, Hungary. Quaternary International. Novothny, A., Frechen, M., Horváth, E., Krbetschek, M., Tsukamoto, S., in press. Infrared stimulated luminescence and radiofluorescence dating of aeolian sediments from Hungary. Quaternary Geochronology, doi:10.1016/j.quageo.2009.05.002. Novothny, A., Frechen, M., Horváth, E., Bradák, B., Oches, E. A., McCoy, W. D., Stevens, T., 2009a. Luminescence and amino acid racemisation chronology of the loess-paleosol sequence at Süttő , Hungary. Quaternary International 198, 62-76. Sierralta, M., Kele, S., Melcher, F., Hambach, U., Reinders, J., van Geldern, R., Frechen, M., in press. Uranium-series dating of travertine from Süttő : Implications for reconstruction of environmental change in Hungary. Quaternary International, doi:10.1016/j.quaint.2009.04.004.

  12. Insights into hydroclimatic variability of Southern California since 125 ka, from multi-proxy analyses of alpine lakes

    Science.gov (United States)

    Glover, K. C.; MacDonald, G. M.; Kirby, M.

    2016-12-01

    Hydroclimatic variability is especially important in California, a water-stressed and increasingly populous region. We assess the range of past hydroclimatic sensitivity and variability in the San Bernardino Mountains of Southern California based on 125 ka of lacustrine sediment records. Geochemistry, charcoal and pollen highlight periods of sustained moisture, aridity and sudden variability driven by orbital and oceanic variations. Marine Isotope Stage 3 (MIS 3) is one such period of greater moisture availability that lasted c. 30 kyr, with smaller-scale perturbations likely reflect North Atlantic Dansgaard-Oeschgar events. Past glacial periods, MIS 4 and MIS 2, display high-amplitude changes. These include periods of reduced forest cover that span millennia, indicating long-lasting aridity. Rapid forest expansion also occurs, marking sudden shifts towards wet conditions. Fire regimes have also changed in tandem with hydroclimate and vegetation. Higher-resolution analysis of the past 10 ka shows that Southern California hydroclimate was broadly similar to other regions of the Southwest and Great Basin, including an orbital and oceanic-driven wet Early Holocene, dry Mid-Holocene, and highly variable Late Holocene. Shorter-term pluvial conditions occur throughout the Holocene, with episodic moisture likely derived from a Pacific source.

  13. Multi-proxy dating of Iceland's major pre-settlement Katla eruption to 822-823 CE

    Czech Academy of Sciences Publication Activity Database

    Büntgen, Ulf; Eggertsson, O.; Wacker, L.; Sigl, M.; Ljungqvist, F. C.; Di Cosmo, N.; Plunkett, G.; Krusic, P. J.; Newfield, T. P.; Esper, J.

    2017-01-01

    Roč. 45, č. 9 (2017), s. 783-786 ISSN 0091-7613 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Late-Antique * Ice core * Greenland * Volcano * Europe Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 4.635, year: 2016

  14. Development and application of multi-proxy indices of land use change for riparian soils in southern New England, USA.

    Science.gov (United States)

    Ricker, M C; Donohue, S W; Stolt, M H; Zavada, M S

    2012-03-01

    Understanding the effects of land use on riparian systems is dependent upon the development of methodologies to recognize changes in sedimentation related to shifts in land use. Land use trends in southern New England consist of shifts from forested precolonial conditions, to colonial and agrarian land uses, and toward modern industrial-urban landscapes. The goals of this study were to develop a set of stratigraphic indices that reflect these land use periods and to illustrate their applications. Twenty-four riparian sites from first- and second-order watersheds were chosen for study. Soil morphological features, such as buried surface horizons (layers), were useful to identify periods of watershed instability. The presence of human artifacts and increases in heavy metal concentration above background levels, were also effective indicators of industrial-urban land use periods. Increases and peak abundance of non-arboreal weed pollen (Ambrosia) were identified as stratigraphic markers indicative of agricultural land uses. Twelve 14C dates from riparian soils indicated that the rise in non-arboreal pollen corresponds to the start of regional deforestation (AD 1749 +/- 56 cal yr; mean +/- 2 SD) and peak non-arboreal pollen concentration corresponds to maximum agricultural land use (AD 1820 +/- 51 cal yr). These indices were applied to elucidate the impact of land use on riparian sedimentation and soil carbon (C) dynamics. This analysis indicated that the majority of sediment and soil organic carbon (SOC) stored in regional riparian soils is of postcolonial origins. Mean net sedimentation rates increased -100-fold during postcolonial time periods, and net SOC sequestration rates showed an approximate 200-fold increase since precolonial times. These results suggest that headwater riparian zones have acted as an effective sink for alluvial sediment and SOC associated with postcolonial land use.

  15. Multi proxy approach to evaluate and delineate the potential of hot springs in the Kotli District (Kashmir, Pakistan)

    Energy Technology Data Exchange (ETDEWEB)

    Anees, M.; Shah, M.; Qureshi, A.; Manzoor, S.

    2017-11-01

    Tattapani hot springs are located near the Kotli District of Azad Kashmir, Pakistan. This study evaluates these hot springs based on surface geological information, radon emission measurements, hydro-geochemical and isotopic signatures and potential source mechanisms. Field observations reveal that the hot springs are located at the crest of the Tattapani anticline along the faulted contact of Cambrian carbonates with Paleocene siliciclastics. In addition, remnants of igneous intrusions in the Cambrian carbonates are commonly observed. Spatial distribution of radon emissions (ranging between 2.1 and 29.5KBq m-3) indicates an anomalous zone located over the Cambrian-Paleocene faulted contact. Hydro-geochemical data show sodium-bicarbonate affinity of hot springs. The highest surface temperature of these springs is recorded at 60.8ºC. Average reservoir temperatures based on silica and cation geo-thermometers are 101ºC and 115ºC, respectively. Giggenbach ternary diagram (Na-K-Mg) suggests a non-equilibrium state between fluid and rock, whereas isotopic and chemical data indicate heat loss by conductive cooling and mixing with groundwater during the flow of thermal water up to the surface. Oxygen and deuterium isotopes indicate that thermal water is of meteoric origin, rain and/or snow in the north at higher altitudes providing the potential recharge. Furthermore, absence of tritium in the thermal water suggests a residence time of more than 50 years.

  16. Deep circulation changes in the South Atlantic since the Last Glacial Maximum from Nd isotope and multi-proxy records

    Science.gov (United States)

    Wei, R.; Abouchami, W.; Zahn, R.; Masque, P.

    2016-01-01

    We report down-core sedimentary Nd isotope (εNd) records from two South Atlantic sediment cores, MD02-2594 and GeoB3603-2, located on the western South African continental margin. The core sites are positioned downstream of the present-day flow path of North Atlantic Deep Water (NADW) and close to the Southern Ocean, which makes them suitable for reconstructing past variability in NADW circulation over the last glacial cycle. The Fe-Mn leachates εNd records show a coherent decreasing trend from glacial radiogenic values towards less radiogenic values during the Holocene. This trend is confirmed by εNd in fish debris and mixed planktonic foraminifera, albeit with an offset during the Holocene to lower values relative to the leachates, matching the present-day composition of NADW in the Cape Basin. We interpret the εNd changes as reflecting the glacial shoaling of Southern Ocean waters to shallower depths combined with the admixing of southward flowing Northern Component Water (NCW). A compilation of Atlantic εNd records reveals increasing radiogenic isotope signatures towards the south and with increasing depth. This signal is most prominent during the Last Glacial Maximum (LGM) and of similar amplitude across the Atlantic basin, suggesting continuous deep water production in the North Atlantic and export to the South Atlantic and the Southern Ocean. The amplitude of the εNd change from the LGM to Holocene is largest in the southernmost cores, implying a greater sensitivity to the deglacial strengthening of NADW at these sites. This signal impacted most prominently the South Atlantic deep and bottom water layers that were particularly deprived of NCW during the LGM. The εNd variations correlate with changes in 231Pa/230Th ratios and benthic δ13C across the deglacial transition. Together with the contrasting 231Pa/230Th: εNd pattern of the North and South Atlantic, this indicates a progressive reorganization of the AMOC to full strength during the Holocene.

  17. A multi-proxy study of sedimentary humic substances in the salt marsh of the Changjiang Estuary, China

    Science.gov (United States)

    Zhang, Yaoling; Du, Jinzhou; Zhao, Xin; Wu, Wangsuo; Peng, Bo; Zhang, Jing

    2014-12-01

    To better understand the origin, composition, and reactivity of sedimentary humic substances (HSs) in salt marshes in the Changjiang Estuary, HS samples were isolated from a sediment core that was collected from the Eastern Chongming salt marsh. Chemical and spectroscopic methods were used to analyze the features of these HSs. The results indicate that the studied HSs in the salt marsh sediments are mainly terrestrial-derived and that the sedimentary organic matter (SOM) in the top layer may contain more organic matter from marine sources and/or autochthonous materials due to the dramatic decreasing of the sediment supply as a result of damming. The degradation of labile carbohydrates and proteins and the preservation of refractory lignin components dominate the early diagenetic reactions of SOM in the salt marsh area. The average contents of the carboxylic groups in FAs and HAs are 11.64 ± 1.08 and 7.13 ± 0.16 meq/gC, and those of phenolic groups are 1.95 ± 0.13 and 2.40 ± 0.44 meq/gC, respectively. The content of carboxylic groups increased with increasing depth, while there were no obvious changes in the content of phenolic groups. The average concentration of total proton-binding sites is approximately 12.5 μmol/g sediment for the studied HSs. These values may provide insight into the migration and fate of HS-bound contaminants in sediments and the overlying sea water in the salt marsh areas of the Changjiang Estuary.

  18. A multi-proxy study of anaerobic ammonium oxidation in marine sediments of the Gullmar Fjord, Sweden

    NARCIS (Netherlands)

    Brandsma, J.; van de Vossenberg, J.; Risgaard-Petersen, N.; Schmid, M.C.; Engstrom, P.; Eurenius, K.; Hulth, S.; Jaeschke, A.; Abbas, B.; Hopmans, E.C.; Strous, M.; Schouten, S.; Jetten, M.S.M.; Sinninghe Damsté, J.S.

    2011-01-01

    Anaerobic ammonium oxidation (anammox) is an important process for nitrogen removal in marine pelagic and benthic environments and represents a major sink in the global nitrogen cycle. We applied a suite of complementary methods for the detection and enumeration of anammox activity and anammox

  19. A multi-proxy study of anaerobic ammonium oxidation in marine sediments of the Gullmar Fjord, Sweden

    DEFF Research Database (Denmark)

    Brandsma, Joost; van de Vossenberg; Risgaard-Petersen, Nils

    2011-01-01

    Anaerobic ammonium oxidation (anammox) is an important process for nitrogen removal in marine pelagic and benthic environments and represents a major sink in the global nitrogen cycle. We applied a suite of complementary methods for the detection and enumeration of anammox activity and anammox...

  20. Interstadial inland dune slacks in south-west Slovakia: a multi-proxy vegetation and landscape reconstruction

    Czech Academy of Sciences Publication Activity Database

    Hájková, Petra; Petr, L.; Horsák, M.; Rohovec, Jan; Hájek, Michal

    2015-01-01

    Roč. 357, Jan 30 (2015), s. 314-328 ISSN 1040-6182 Institutional support: RVO:67985939 ; RVO:67985831 Keywords : Late Glacial * Western Carpathians * palaeoecological reconstruction Subject RIV: EF - Botanics Impact factor: 2.067, year: 2015

  1. 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

  2. Performance of Solar Proxy Options of IRI-Plas Model for Equinox Seasons

    Science.gov (United States)

    Sezen, Umut; Gulyaeva, Tamara L.; Arikan, Feza

    2018-02-01

    International Reference Ionosphere (IRI) is the most acclaimed climatic model of the ionosphere. Since 2009, the range of the IRI model has been extended to the Global Positioning System (GPS) orbital height of 20,000 km in the plasmasphere. The new model, which is called IRI extended to Plasmasphere (IRI-Plas), can input not only the ionosonde foF2 and hmF2 but also the GPS-total electron content (TEC). IRI-Plas has been provided at www.ionolab.org, where online computation of ionospheric parameters is accomplished through a user-friendly interface. The solar proxies that are available in IRI-Plas can be listed as sunspot number (SSN1), SSN2, F10.7, global electron content (GEC), TEC, IG, Mg II, Lyman-α, and GEC_RZ. In this study, ionosonde foF2 data are compared with IRI-Plas foF2 values with the Consultative Committee International Radio (CCIR) and International Union of Radio Science (URSI) model choices for each solar proxy, with or without the GPS-TEC input for the equinox months of October 2011 and March 2015. It has been observed that the best fitting model choices in Root Mean Square (RMS) and Normalized RMS (NRMS) sense are the Jet Propulsion Laboratory global ionospheric maps-TEC input with Lyman-α solar proxy option for both months. The input of TEC definitely lowers the difference between the model and ionosonde foF2 values. The IG and Mg II solar proxies produce similar model foF2 values, and they usually are the second and third best fits to the ionosonde foF2 for the midlatitude ionosphere. In high-latitude regions, Jet Propulsion Laboratory global ionospheric map-TEC inputs to IRI-Plas with Lyman-α, GEC_RZ, and TEC solar proxies are the best choices. In equatorial region, the best fitting solar proxies are IG, Lyman-α, and Mg II.

  3. Assessing the quality of life of children with sickle cell anaemia using self-, parent-proxy, and health care professional-proxy reports.

    Science.gov (United States)

    Constantinou, Christina; Payne, Nicola; Inusa, Baba

    2015-05-01

    The quality of life (QoL) of children with sickle cell anaemia (SCA) in the United Kingdom has not been examined, and a discrepancy measure based on Gap theory has rarely been used. This study investigated whether (1) child self-reports of QoL using a discrepancy measure (the Generic Children's QoL Measure; GCQ) are lower than those from healthy children, (2) proxy reports from parents and health care professionals are lower than child self-reports, and (3) demographic and disease severity indicators are related to QoL. An interdependent groups, cross-sectional design was implemented. Seventy-four children with SCA, their parent, and members of their health care team completed the GCQ. Demographic and disease severity indicators were recorded. GCQ data from healthy children were obtained from the UK Data Archive. Contrary to past research, when examining generic discrepancy QoL, children with SCA did not report a lower QoL than healthy children, and parent- and health care professional-proxy reports were not lower than child self-reports. Few of the demographic and disease severity indicators were related to QoL. Proxy reports may be used to gain a more complete picture of QoL, but should not be a substitute for self-reports. The explanation for the relatively high levels of QoL reported is not clear, but children with SCA may have realistic expectations about their ideal-self, place greater emphasis on aspects other than health in shaping their QoL, and define achievements within the limits of their illness. Future research should focus on psychological factors in explaining QoL. Statement of contribution What is already known on this subject? Children with sickle cell disease (SCD) generally have a reduced QoL compared with healthy children, but there appears to be no research measuring QoL in paediatric SCD in the United Kingdom. Proxy QoL reports from parents are often lower than child self-reports, but there is less research examining proxy reports from health

  4. 40K in the Black Sea: a proxy to estimate biogenic sedimentation

    International Nuclear Information System (INIS)

    Gulin, S.B.; Gulina, L.V.; Sidorov, I.G.; Proskurnin, V.Yu.; Duka, M.S.; Moseichenko, I.N.; Rodina, E.A.

    2014-01-01

    An approach to estimate the rate of biogenic sedimentation in the Black Sea using the naturally occurring radionuclide 40 K has been considered. It allows assessment of the contribution of suspended matter of biological origin to the overall sediment accumulation in the Black Sea coastal, shelf and deep-water areas. Based upon this method, a relationship between the biogenic fraction of the seabed sediments and the water depth has been established with a view to differentiating the contributions of allochthonous and autochthonous suspended matter to the sedimentation rate. Overall, 40 K can be considered as an easily applicable proxy to assess sedimentation rate of biogenic fraction of particulate matter in marine environments. - Highlights: • 40 K-based approach was developed to assess biogenic sedimentation in the Black Sea. • 40 K-derived relationship between biogenic sedimentation and water depth was traced. • 40 K is an easily applicable proxy to estimate rate of biogenic sedimentation in sea

  5. 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.

  6. PROXiMATE: a database of mutant protein-protein complex thermodynamics and kinetics.

    Science.gov (United States)

    Jemimah, Sherlyn; Yugandhar, K; Michael Gromiha, M

    2017-09-01

    We have developed PROXiMATE, a database of thermodynamic data for more than 6000 missense mutations in 174 heterodimeric protein-protein complexes, supplemented with interaction network data from STRING database, solvent accessibility, sequence, structural and functional information, experimental conditions and literature information. Additional features include complex structure visualization, search and display options, download options and a provision for users to upload their data. The database is freely available at http://www.iitm.ac.in/bioinfo/PROXiMATE/ . The website is implemented in Python, and supports recent versions of major browsers such as IE10, Firefox, Chrome and Opera. gromiha@iitm.ac.in. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  7. A Study of Practical Proxy Reencryption with a Keyword Search Scheme considering Cloud Storage Structure

    Directory of Open Access Journals (Sweden)

    Sun-Ho Lee

    2014-01-01

    Full Text Available 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.

  8. ePRISM: A case study in multiple proxy and mixed temporal resolution integration

    Science.gov (United States)

    Robinson, Marci M.; Dowsett, Harry J.

    2010-01-01

    As part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project, we present the ePRISM experiment designed I) to provide climate modelers with a reconstruction of an early Pliocene warm period that was warmer than the PRISM interval (similar to 3.3 to 3.0 Ma), yet still similar in many ways to modern conditions and 2) to provide an example of how best to integrate multiple-proxy sea surface temperature (SST) data from time series with varying degrees of temporal resolution and age control as we begin to build the next generation of PRISM, the PRISM4 reconstruction, spanning a constricted time interval. While it is possible to tie individual SST estimates to a single light (warm) oxygen isotope event, we find that the warm peak average of SST estimates over a narrowed time interval is preferential for paleoclimate reconstruction as it allows for the inclusion of more records of multiple paleotemperature proxies.

  9. 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.

  10. A Multi-homed VPN Architecture Based on Extended SOCKS+TLS Protocols

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A multi-homed VPN architecture based on extended SOCKSv5 and TLS was proposed. The architecture employs a dynamic connection mechanism for multiple proxies in the end system,in which the security-demanded transmission connections can switch smoothly among the multiple proxies by maintaining a coherent connection context. The mechanism is transparent to application programs and can support the building of VPN. With the cooperation of some other security components,the mechanism guarantees the resource availability and reliability of the end system against some attacks to the specific ports or hosts.

  11. Residual β activity of particulate 234Th as a novel proxy for tracking sediment resuspension in the ocean

    Science.gov (United States)

    Lin, Wuhui; Chen, Liqi; Zeng, Shi; Li, Tao; Wang, Yinghui; Yu, Kefu

    2016-01-01

    Sediment resuspension occurs in the global ocean, which greatly affects material exchange between the sediment and the overlying seawater. The behaviours of carbon, nutrients, heavy metals, and other pollutants at the sediment-seawater boundary will further link to climate change, eutrophication, and marine pollution. Residual β activity of particulate 234Th (RAP234) is used as a novel proxy to track sediment resuspension in different marine environments, including the western Arctic Ocean, the South China Sea, and the Southern Ocean. Sediment resuspension identified by high activity of RAP234 is supported by different lines of evidence including seawater turbidity, residence time of total 234Th, Goldschmidt’s classification, and ratio of RAP234 to particulate organic carbon. A conceptual model is proposed to elucidate the mechanism for RAP234 with dominant contributions from 234Th-238U and 212Bi-228Th. The ‘slope assumption’ for RAP234 indicated increasing intensity of sediment resuspension from spring to autumn under the influence of the East Asian monsoon system. RAP234 can shed new light on 234Th-based particle dynamics and should benefit the interpretation of historical 234Th-238U database. RAP234 resembles lithophile elements and has broad implications for investigating particle dynamics in the estuary-shelf-slope-ocean continuum and linkage of the atmosphere-ocean-sediment system. PMID:27252085

  12. Residual β activity of particulate (234)Th as a novel proxy for tracking sediment resuspension in the ocean.

    Science.gov (United States)

    Lin, Wuhui; Chen, Liqi; Zeng, Shi; Li, Tao; Wang, Yinghui; Yu, Kefu

    2016-06-02

    Sediment resuspension occurs in the global ocean, which greatly affects material exchange between the sediment and the overlying seawater. The behaviours of carbon, nutrients, heavy metals, and other pollutants at the sediment-seawater boundary will further link to climate change, eutrophication, and marine pollution. Residual β activity of particulate (234)Th (RAP234) is used as a novel proxy to track sediment resuspension in different marine environments, including the western Arctic Ocean, the South China Sea, and the Southern Ocean. Sediment resuspension identified by high activity of RAP234 is supported by different lines of evidence including seawater turbidity, residence time of total (234)Th, Goldschmidt's classification, and ratio of RAP234 to particulate organic carbon. A conceptual model is proposed to elucidate the mechanism for RAP234 with dominant contributions from (234)Th-(238)U and (212)Bi-(228)Th. The 'slope assumption' for RAP234 indicated increasing intensity of sediment resuspension from spring to autumn under the influence of the East Asian monsoon system. RAP234 can shed new light on (234)Th-based particle dynamics and should benefit the interpretation of historical (234)Th-(238)U database. RAP234 resembles lithophile elements and has broad implications for investigating particle dynamics in the estuary-shelf-slope-ocean continuum and linkage of the atmosphere-ocean-sediment system.

  13. Analisa Pemanfaatan Proxy Server Sebagai Media Filtering Dan Caching Pada Jaringan Komputer

    OpenAIRE

    -, Yuisar; Yulianti, Liza; H, Yanolanda Suzantri

    2015-01-01

    This research aims to Implement control and safe use of the internet at an agency with a utilization fee seminal may use the Linux operating system Ubuntu 14:04. Bandwidth division according to the time of busy servers and Internet client. To quick opening for the second time and so on. Blocking sites - porn site that tends to contain spyware. Accelerate video audio streaming. This study uses experimental research. In this study conducted experiments on the performance of the proxy server tha...

  14. Důvěryhodná proxy v SSL/TLS spojení

    OpenAIRE

    Smolík, Jiří

    2017-01-01

    The problem of SSL/TLS interception ("trusted proxy in SSL/TLS connection") has been known for years and many implementations exist. However, all of them share a single technical solution which is based solely on the PKI authentication mechanism and suffers from multiple serious disadvantages. Most importantly, it is not compatible with several aspects or future trends of SSL/TLS and PKI, there's almost no space for improvement and its real use may spawn legal issues. After we analyze technic...

  15. Revocable identity-based proxy re-signature against signing key exposure.

    Science.gov (United States)

    Yang, Xiaodong; Chen, Chunlin; Ma, Tingchun; Wang, Jinli; Wang, Caifen

    2018-01-01

    Identity-based proxy re-signature (IDPRS) is a novel cryptographic primitive that allows a semi-trusted proxy to convert a signature under one identity into another signature under another identity on the same message by using a re-signature key. Due to this transformation function, IDPRS is very useful in constructing privacy-preserving schemes for various information systems. Key revocation functionality is important in practical IDPRS for managing users dynamically; however, the existing IDPRS schemes do not provide revocation mechanisms that allow the removal of misbehaving or compromised users from the system. In this paper, we first introduce a notion called revocable identity-based proxy re-signature (RIDPRS) to achieve the revocation functionality. We provide a formal definition of RIDPRS as well as its security model. Then, we present a concrete RIDPRS scheme that can resist signing key exposure and prove that the proposed scheme is existentially unforgeable against adaptive chosen identity and message attacks in the standard model. To further improve the performance of signature verification in RIDPRS, we introduce a notion called server-aided revocable identity-based proxy re-signature (SA-RIDPRS). Moreover, we extend the proposed RIDPRS scheme to the SA-RIDPRS scheme and prove that this extended scheme is secure against adaptive chosen message and collusion attacks. The analysis results show that our two schemes remain efficient in terms of computational complexity when implementing user revocation procedures. In particular, in the SA-RIDPRS scheme, the verifier needs to perform only a bilinear pairing and four exponentiation operations to verify the validity of the signature. Compared with other IDPRS schemes in the standard model, our SA-RIDPRS scheme greatly reduces the computation overhead of verification.

  16. Poor-to-moderate agreement between self and proxy interviews of mobile phone use.

    Science.gov (United States)

    Hutter, Hans-Peter; Ehrenhöfer, Lisa; Freuis, Edith; Hartl, Patrik; Kundi, Michael

    2012-10-01

    In epidemiological studies, cases cannot always be interviewed due to them being too ill or already deceased. Under these circumstances, proxy interviews are often conducted; however, the veridicality of information about mobile phone use gained by proxy interviews has been doubted. The issue is undecided due to the lack of empirical data. We conducted a study of 119 heterosexual couples. Both partners answered two questionnaires about mobile phone use, one about their own use and one about their partner's use. Overall agreement assessed using Cohen's kappa, Passing and Bablok regression, and concordance coefficients between self and proxy data was poor to moderate (e.g., concordance coefficients of 0.55 for duration of use). The only item with good agreement was whether or not a prepaid phone was used (Cohen's kappa 0.78 and 0.63 for male and female estimates, respectively), and to a lesser degree, the onset of mobile phone use (concordance coefficients of 0.66 and 0.61). Poorest agreement was obtained for the side of the head the mobile phone was held during calls (kappa coefficients of 0.20 and 0.24 for female and male estimates, respectively). We conclude that the assessment of mobile phone use by proxy data cannot be relied on except for information about onset of mobile phone use, use of prepaid or contract phones, and, to a lesser degree, duration of daily use. Agreement concerning the important information about side of the head the mobile phone is held during calls was poorest and only slightly better than chance. Copyright © 2012 Wiley Periodicals, Inc.

  17. Level of agreement between patient and proxy responses to the EQ-5D health questionnaire 12 months after injury.

    Science.gov (United States)

    Gabbe, Belinda J; Lyons, Ronan A; Sutherland, Ann M; Hart, Melissa J; Cameron, Peter A

    2012-04-01

    Health-related quality of life represents a patient's experiences and expectations and should be collected from the patient. In trauma, collection of information from the patient can be challenging, particularly for subgroups where cognitive impairment is prevalent, increasing reliance on proxy reporting. This study assessed the agreement between patient and proxy reporting of health-related quality of life 12 months after injury. The Victorian State Trauma Registry and Victorian Orthopaedic Trauma Outcomes Registry collect EQ-5D data at 12 months after injury. Cases where data were collected from the patient and proxy were extracted. Agreement between patient and proxy responses was compared using kappa (K) coefficients for the individual EQ-5D items, and Bland-Altman plots and Wilcoxon signed-rank tests for the EQ-5D summary score and visual analog scale (VAS). Agreement between patient and proxy respondents was substantial for the mobility (K = 0.61) and personal care items (K = 0.67) and moderate for the usual activities (K = 0.50), pain/discomfort (K = 0.42), and anxiety/depression items (K = 0.47). The mean difference between proxy and patient-reported scores for the VAS (0.74, 95% confidence interval: -2.73, 4.21) and the EQ-5D summary score (-0.02, 95% confidence interval: -0.07, 0.03) was small, but the limits of agreement were wide (-34.22 to 35.71 for VAS and -0.55 to 0.51 for summary score), suggesting no systematic bias. Although proxy and patient responses for the EQ-5D VAS may differ, the differences show random variability rather than systematic bias. Group comparisons using proxy responses are unlikely to be biased, but proxy responses should be used with caution when assessing individual patient recovery.

  18. Parent proxy-reported quality of life for children with cerebral palsy: is it related to parental psychosocial distress?

    Science.gov (United States)

    Davis, E; Mackinnon, A; Waters, E

    2012-07-01

    Parent-proxy reports of quality of life (QOL) are often used to guide decisions about children with cerebral palsy (CP), although little is known about the factors that influence parent-proxy reports. The aim of this study was to examine (i) the relationship between parental psychosocial distress and parent proxy-reported QOL; and (ii) whether parental psychosocial distress mediates the relationship between child impairment and proxy-reported QOL. A sample of 201 primary caregivers of children aged 4-12 years with CP completed the Cerebral Palsy Quality of Life Questionnaire for Children, a condition-specific QOL instrument, and a measure of psychosocial distress, the Kessler 10. The children, evenly distributed by gender (56% male) were sampled across Gross Motor Function Classification System levels (Level I = 18%, II = 28%, III = 14%, IV = 11%, V = 27%). Consistent with the hypotheses, parental distress was negatively correlated with all domains of parent proxy-reported QOL (r = -0.18 to r = -0.55). The relationship between impairment and proxy-reported QOL was mediated by parental distress for five of the seven domains of QOL (social well-being and acceptance, feelings about functioning, participation and physical health, emotional well-being and self-esteem, and pain and impact of disability). Child impairment did not predict access to services or family health. This is the first study that assesses the relationship between parental distress and proxy-reported QOL for children with CP. Although the cross-sectional nature of the available data precludes any statements of causality, the results suggest that, when using parent proxy, the parents' psychological state should also be measured. This is particularly important when, as is often the case for child disability research, proxy-reported QOL are the only available data. © 2011 Blackwell Publishing Ltd.

  19. An ordination of life histories using morphological proxies: capital vs. income breeding in insects.

    Science.gov (United States)

    Davis, Robert B; Javoiš, Juhan; Kaasik, Ants; Õunap, Erki; Tammaru, Toomas

    2016-08-01

    Predictive classifications of life histories are essential for evolutionary ecology. While attempts to apply a single approach to all organisms may be overambitious, recent advances suggest that more narrow ordination schemes can be useful. However, these schemes mostly lack easily observable proxies of the position of a species on respective axes. It has been proposed that, in insects, the degree of capital (vs. income) breeding, reflecting the importance of adult feeding for reproduction, correlates with various ecological traits at the level of among-species comparison. We sought to prove these ideas via rigorous phylogenetic comparative analyses. We used experimentally derived life-history data for 57 species of European Geometridae (Lepidoptera), and an original phylogenetic reconstruction. The degree of capital breeding was estimated based on morphological proxies, including relative abdomen size of females. Applying Brownian-motion-based comparative analyses (with an original update to include error estimates), we demonstrated the associations between the degree of capital breeding and larval diet breadth, sexual size dimorphism, and reproductive season. Ornstein-Uhlenbeck model based phylogenetic analysis suggested a causal relationship between the degree of capital breeding and diet breadth. Our study indicates that the gradation from capital to income breeding is an informative axis to ordinate life-history strategies in flying insects which are affected by the fecundity vs. mobility trade off, with the availability of easy to record proxies contributing to its predictive power in practical contexts. © 2016 by the Ecological Society of America.

  20. 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.

  1. 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.

  2. Development of a proxy-reported pulmonary outcome scale for preterm infants with bronchopulmonary dysplasia

    Directory of Open Access Journals (Sweden)

    Laughon Matthew M

    2011-07-01

    Full Text Available Abstract Background To develop an accurate, proxy-reported bedside measurement tool for assessment of the severity of bronchopulmonary dysplasia (also called chronic lung disease in preterm infants to supplement providers' current biometric measurements of the disease. Methods We adapted Patient-Reported Outcomes Measurement Information System (PROMIS methodology to develop the Proxy-Reported Pulmonary Outcomes Scale (PRPOS. A multidisciplinary group of registered nurses, nurse practitioners, neonatologists, developmental specialists, and feeding specialists at five academic medical centers participated in the PRPOS development, which included five phases: (1 identification of domains, items, and responses; (2 item classification and selection using a modified Delphi process; (3 focus group exploration of items and response options; (4 cognitive interviews on a preliminary scale; and (5 final revision before field testing. Results Each phase of the process helped us to identify, classify, review, and revise possible domains, questions, and response options. The final items for field testing include 26 questions or observations that a nurse assesses before, during, and after routine care time and feeding. Conclusions We successfully created a prototype scale using modified PROMIS methodology. This process can serve as a model for the development of proxy-reported outcomes scales in other pediatric populations.

  3. POLAR NETWORK INDEX AS A MAGNETIC PROXY FOR THE SOLAR CYCLE STUDIES

    International Nuclear Information System (INIS)

    Priyal, Muthu; Banerjee, Dipankar; Ravindra, B.; Singh, Jagdev; Karak, Bidya Binay; Muñoz-Jaramillo, Andrés; Choudhuri, Arnab Rai

    2014-01-01

    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

  4. 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.

  5. 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.

  6. 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.

  7. POLAR NETWORK INDEX AS A MAGNETIC PROXY FOR THE SOLAR CYCLE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Priyal, Muthu; Banerjee, Dipankar; Ravindra, B.; Singh, Jagdev [Indian Institute of Astrophysics,Koramangala, Bengaluru 560034 (India); Karak, Bidya Binay [Nordita, KTH Royal Institute of Technology and Stockholm University (Sweden); Muñoz-Jaramillo, Andrés [Montana State University, Bozeman, MT 59717 (United States); Choudhuri, Arnab Rai, E-mail: mpriya@iiap.res.in, E-mail: dipu@iiap.res.in [Indian Institute of Science, Bangalore (India)

    2014-09-20

    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.

  8. 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.

  9. 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.

  10. Objective spatiotemporal proxy-model comparisons of the Asian monsoon for the last millennium

    Science.gov (United States)

    Anchukaitis, K. J.; Cook, E. R.; Ammann, C. M.; Buckley, B. M.; D'Arrigo, R. D.; Jacoby, G.; Wright, W. E.; Davi, N.; Li, J.

    2008-12-01

    The Asian monsoon system can be studied using a complementary proxy/simulation approach which evaluates climate models using estimates of past precipitation and temperature, and which subsequently applies the best understanding of the physics of the climate system as captured in general circulation models to evaluate the broad-scale dynamics behind regional paleoclimate reconstructions. Here, we use a millennial-length climate field reconstruction of monsoon season summer (JJA) drought, developed from tree- ring proxies, with coupled climate simulations from NCAR CSM1.4 and CCSM3 to evaluate the cause of large- scale persistent droughts over the last one thousand years. Direct comparisons are made between the external forced response within the climate model and the spatiotemporal field reconstruction. In order to identify patterns of drought associated with internal variability in the climate system, we use a model/proxy analog technique which objectively selects epochs in the model that most closely reproduce those observed in the reconstructions. The concomitant ocean-atmosphere dynamics are then interpreted in order to identify and understand the internal climate system forcing of low frequency monsoon variability. We examine specific periods of extensive or intensive regional drought in the 15th, 17th, and 18th centuries, many of which are coincident with major cultural changes in the region.

  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. Bivariate spatial analysis of temperature and precipitation from general circulation models and observation proxies

    KAUST Repository

    Philbin, R.; Jun, M.

    2015-01-01

    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.

  13. 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.

  14. 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.

  15. Description of the skeleton of the fossil beaked whale Messapicetus gregarius: searching potential proxies for deep-diving abilities

    Directory of Open Access Journals (Sweden)

    B. Ramassamy

    2018-01-01

    Full Text Available Ziphiidae (beaked whales are a successful family of medium- to large-sized toothed whales. Their extant members perform regular deep dives beyond the photic zone to forage for cephalopods and fish. Conversely, extinct long-snouted stem ziphiids are interpreted as epipelagic predators. However, some aspects of this hypothesis remain unclear due to the lack of clear morphological proxies for recognizing regular deep divers. We compared the forelimb, neck, and pterygoid sinus system of the fossil ziphiid Messapicetus gregarius with those of other odontocetes to evaluate the potential of these body regions as proxies to assess deep-diving specialization. The reconstructed musculature of the neck and forelimb of M. gregarius was also compared with that of other odontocetes. We also quantified variation in the proportions of the forelimb and the hamular fossa of the pterygoid sinus (HF using 16 linear measurements. The degree of association between diving behaviour in extant odontocetes and these measurements was evaluated with and without phylogenetic correction. Reconstruction of the neck musculature suggests that M. gregarius possessed a neck more flexible than most extant ziphiids due to the lower degree of fusion of the cervical vertebrae and the large insertions for the M. longus colli and Mm. intertransversarii ventrales cervicis. While neck rigidity might be related to deep diving, differences in neck flexibility among extant ziphiids indicate a more complex functional interpretation. The relationship between forelimb morphology and diving behaviour was not significant, both with and without phylogenetic correction, suggesting that it cannot be used to assess deep-diving abilities with the parameters considered here. Measurements of the HF revealed successful to evaluate deep-diving abilities in odontocetes, with an enlargement of this structure in deep divers. Considering other evidence that suggests an epipelagic behaviour, we propose

  16. Testing the benthic foraminiferal B/Ca proxy in a hydrothermal vent environment to determine its validity under extreme conditions

    Science.gov (United States)

    Clementi, V.; Haynes, L.; Hoenisch, B.; Costa, K.; McManus, J. F.

    2016-12-01

    The boron to calcium ratio (B/Ca) and boron isotopic composition of the benthic foraminifer C. wuellerstorfi have become frequently used proxies for reconstructing carbonate chemistry in ocean bottom waters. However, elevated boron isotope data from a site proximal to the Clipperton Fracture Zone on the East Pacific Rise have led to the hypothesis that boron derived from hydrothermal fluids may be incorporated into benthic foraminifer shells (1). To date there is no comparable evidence for B/Ca at sites adjacent to hydrothermal vent systems, but hydrothermal vent fluid at the Juan de Fuca Ridge in the northeast Pacific Ocean can have boron concentrations nearly twice as high as ambient seawater (2), and other studies have documented increased levels of trace element incorporation in foraminifers living near hydrothermal vents (3). If the same effect holds true for B/Ca, the proxy may be compromised in sediments near hydrothermal vent sites. Here we present C. wuellerstorfi B/Ca data from a sediment core 5 km west of the Juan de Fuca Ridge, North Cleft Segment, to study the influence of vent fluid chemistry and partial shell dissolution on B/Ca and other trace element ratios. Our results do not show a strong hydrothermal signature on B/Ca despite the elevated boron concentrations of modern vent fluids and close proximity to the ridge. However, partial shell dissolution appears to have a significant impact on B/Ca ratios, calling for careful sample selection in future reconstructions from the region. Analysis of B/Ca and other trace element ratios across a ridge transect at a time of documented high hydrothermal activity—as indicated by high sediment hydrothermal Fe fluxes—may determine whether the hydrothermal signal is recorded further downstream from the vent fluid source. (1) Raitzsch, M. and Hönisch, B. (2010). Geology 40(5). (2) Seyfried Jr., W.E. et al. (2003). Journal of Geophys. Res.:Solid Earth 108(B9). (3) Munsel, D. et al. (2010). Biogeosci. 7.7.

  17. Comparison of Geochemical, Grain-Size, and Magnetic Proxies for Rock Flour and Ice- Rafted Debris in the Late Pleistocene Mono Basin, CA

    Science.gov (United States)

    Zimmerman, S. H.; Hemming, S. R.; Kent, D. V.

    2008-12-01

    Advance and retreat of mountain glaciers are important indicators of climate variability, but the most direct proxy record, mapping and dating of moraines, is by nature discontinous. The Sierra Nevada form the western boundary of the Mono Lake basin, and the proximity of the large Pleistocene lake to the glacial canyons of the Sierra presents a rare opportunity to examine glacial variability in a continuous, well-dated lacustrine sequence. We have applied a geochemical proxy for rock flour to the glacial silts of the late Pleistocene Wilson Creek Formation, but because it is time- and sample-intensive, another method is required for a high-resolution record. Previous microscopic examination, thermomagnetic measurements, XRD analysis, and new isothermal remnant magnetization (IRM) acquisition curves show that the magnetic mineralogy is dominated by fine-grained, unaltered magnetite. Bulk measurements show strong susceptibility (mean ~ 16 x 10- 6 m3/kg) and remanent magnetization (mean IRM ~ 10-2 Am2/kg) compared to diluting components (carbonate, smectite, rhyolitic ash). The Wilson Creek type section sediments also contain a coarse lithic fraction, quantified by counting the >2cm clasts in outcrop and the >425 μm fraction in the bulk sediment. Susceptibility, IRM, and ARM (anhysteretic remnant magnetization) are quite similar throughout the type section, with the abundance of coarse lithic fraction correlative to the ratio k/IRM. Because the magnetic fraction of the rock flour is fine-grained magnetite, IRM should capture the changes in concentration of flour through time, and the major features of the (low-resolution) geochemical flour proxy record are identifiable in the IRM record. Flux-correction of the IRM results in a rock flour proxy record with major peaks between 36 and 48 ka, similar to a rock flour record from neighboring Owens Lake. This regional glacial signal contrasts with peaks in coarse lithics between 58 and 68 ka in the Wilson Creek record

  18. Evidence of bottom-up limitations in nearshore marine systems based on otolith proxies of fish growth

    Science.gov (United States)

    von Biela, Vanessa R.; Kruse, Gordon H.; Mueter, Franz J.; Black, Bryan A.; Douglas, David C.; Helser, Thomas E.; Zimmerman, Christian E.

    2015-01-01

    Fish otolith growth increments were used as indices of annual production at nine nearshore sites within the Alaska Coastal Current (downwelling region) and California Current (upwelling region) systems (~36–60°N). Black rockfish (Sebastes melanops) and kelp greenling (Hexagrammos decagrammus) were identified as useful indicators in pelagic and benthic nearshore food webs, respectively. To examine the support for bottom-up limitations, common oceanographic indices of production [sea surface temperature (SST), upwelling, and chlorophyll-a concentration] during summer (April–September) were compared to spatial and temporal differences in fish growth using linear mixed models. The relationship between pelagic black rockfish growth and SST was positive in the cooler Alaska Coastal Current and negative in the warmer California Current. These contrasting growth responses to SST among current systems are consistent with the optimal stability window hypothesis in which pelagic production is maximized at intermediate levels of water column stability. Increased growth rates of black rockfish were associated with higher chlorophyll concentrations in the California Current only, but black rockfish growth was unrelated to the