WorldWideScience

Sample records for inter annual variability

  1. Improving uncertainty estimates: Inter-annual variability in Ireland

    Science.gov (United States)

    Pullinger, D.; Zhang, M.; Hill, N.; Crutchley, T.

    2017-11-01

    This paper addresses the uncertainty associated with inter-annual variability used within wind resource assessments for Ireland in order to more accurately represent the uncertainties within wind resource and energy yield assessments. The study was undertaken using a total of 16 ground stations (Met Eireann) and corresponding reanalysis datasets to provide an update to previous work on this topic undertaken nearly 20 years ago. The results of the work demonstrate that the previously reported 5.4% of wind speed inter-annual variability is considered to be appropriate, guidance is given on how to provide a robust assessment of IAV using available sources of data including ground stations, MERRA-2 and ERA-Interim.

  2. Large-Scale Processes Associated with Inter-Decadal and Inter-Annual Early Spring Rainfall Variability in Taiwan

    Directory of Open Access Journals (Sweden)

    Jau-Ming Chen

    2016-02-01

    Full Text Available Early spring (March - April rainfall in Taiwan exhibits evident and distinct inter-annual and inter-decadal variability. The inter-annual varibility has a positive correlation with the El Niño/Southern Oscillation while the inter-decadal variability features a phase change beginning in the late 1970s, coherent with the major phase change in the Pacific decadal oscillation. Rainfall variability in both timescales is regulated by large-scale processes showing consistent dynamic features. Rainfall increases are associated with positive sea surface temperature (SST anomalies in the tropical eastern Pacific and negative SST anomalies in the tropical central Pacific. An anomalous lower-level divergent center appears in the tropical central Pacific. Via a Rossby-wave-like response, an anomalous lower-level anticyclone appears to the southeast of Taiwan over the Philippine Sea-tropical western Pacific region, which is accompanied by an anomalous cyclone to the north-northeast of Taiwan. Both circulation anomalies induce anomalous southwesterly flows to enhance moisture flux from the South China Sea onto Taiwan, resulting in significant moisture convergence nearby Taiwan. With enhanced moisture supplied by anomalous southwesterly flows, significant rainfall increases occur in both inter-annual and inter-decadal timescales in early spring rainfall on Taiwan.

  3. Effect of inter- and intra-annual thermohaline variability on acoustic propagation

    Science.gov (United States)

    Chu, Peter C.; McDonald, Colleen M.; Kucukosmanoglu, Murat; Judono, Albert; Margolina, Tetyana; Fan, Chenwu

    2017-05-01

    This paper is to answer the question "How can inter- and intra-annual variability in the ocean be leveraged by the submarine Force?" through quantifying inter- and intra-annual variability in (T, S) fields and in turn underwater acoustic characteristics such as transmission loss, signal excess, and range of detection. The Navy's Generalized Digital Environmental Model (GDEM) is the climatological monthly mean data and represents mean annual variability. An optimal spectral decomposition method is used to produce a synoptic monthly gridded (SMG) (T, S) dataset for the world oceans with 1° ×1° horizontal resolution, 28 vertical levels (surface to 3,000 m depth), monthly time increment from January 1945 to December 2014 now available at the NOAA/NCEI website: http://data.nodc.noaa.gov/cgibin/iso?id=gov.noaa.nodc:0140938. The sound velocity decreases from 1945 to 1975 and increases afterwards due to global climate change. Effect of the inter- and intra-annual (T, S) variability on acoustic propagation in the Yellow Sea is investigated using a well-developed acoustic model (Bellhop) in frequencies from 3.5 kHz to 5 kHz with sound velocity profile (SVP) calculated from GDEM and SMG datasets, various bottom types (silty clay, fine sand, gravelly mud, sandy mud, and cobble or gravel) from the NAVOCEANO`s High Frequency Environmental Algorithms (HFEVA), source and receiver depths. Acoustic propagation ranges are extended drastically due to the inter-annual variability in comparison with the climatological SVP (from GDEM). Submarines' vulnerability of detection as its depth varies and avoidance of short acoustic range due to inter-annual variability are also discussed.

  4. The impact of inter-annual variability of annual cycle on long-term memory in long historical temperature records

    Science.gov (United States)

    Deng, Qimin; Fu, Zuntao

    2017-04-01

    Changes in the estimation of long-term correlation induced by inter-annual variability of annual cycle have been investigated by means of detrended fluctuation analysis (DFA). In a consequence of the intrinsic nonlinearity of the climate system, the annual cycle suffers from both amplitude and phase fluctuations. How does this changing annual cycle affect the fluctuation of temperature anomalies? A recently developed adaptive data analysis tool, the Nonlinear Mode Decomposition (NMD), is used to extract and remove time-varying annual cycle. We compared the differences of the long-term correlation calculated by removing different annual cycle, time-varying and stationary. The study was based on long historical temperature records around the North Atlantic Ocean. The traditional climatology annual cycle which lack characteristic of inter-annual fluctuation would lead to: (1) the estimation of Hurst exponent (2) how to choose scaling range and (3) the goodness of fit. Especially removing steady climatology annual cycle would introduce an artificial crossover around one-year period in the DFA curve. The conclusion is verified by generating deterministic time series through Monte Carlo simulations.

  5. The impact of inter-annual rainfall variability on African savannas changes with mean rainfall.

    Science.gov (United States)

    Synodinos, Alexis D; Tietjen, Britta; Lohmann, Dirk; Jeltsch, Florian

    2018-01-21

    Savannas are mixed tree-grass ecosystems whose dynamics are predominantly regulated by resource competition and the temporal variability in climatic and environmental factors such as rainfall and fire. Hence, increasing inter-annual rainfall variability due to climate change could have a significant impact on savannas. To investigate this, we used an ecohydrological model of stochastic differential equations and simulated African savanna dynamics along a gradient of mean annual rainfall (520-780 mm/year) for a range of inter-annual rainfall variabilities. Our simulations produced alternative states of grassland and savanna across the mean rainfall gradient. Increasing inter-annual variability had a negative effect on the savanna state under dry conditions (520 mm/year), and a positive effect under moister conditions (580-780 mm/year). The former resulted from the net negative effect of dry and wet extremes on trees. In semi-arid conditions (520 mm/year), dry extremes caused a loss of tree cover, which could not be recovered during wet extremes because of strong resource competition and the increased frequency of fires. At high mean rainfall (780 mm/year), increased variability enhanced savanna resilience. Here, resources were no longer limiting and the slow tree dynamics buffered against variability by maintaining a stable population during 'dry' extremes, providing the basis for growth during wet extremes. Simultaneously, high rainfall years had a weak marginal benefit on grass cover due to density-regulation and grazing. Our results suggest that the effects of the slow tree and fast grass dynamics on tree-grass interactions will become a major determinant of the savanna vegetation composition with increasing rainfall variability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. ENSO Related Inter-Annual Lightning Variability from the Full TRMM LIS Lightning Climatology

    Science.gov (United States)

    Clark, Austin; Cecil, Daniel

    2018-01-01

    The El Nino/Southern Oscillation (ENSO) contributes to inter-annual variability of lightning production more than any other atmospheric oscillation. This study further investigated how ENSO phase affects lightning production in the tropics and subtropics using the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS). Lightning data were averaged into mean annual warm, cold, and neutral 'years' for analysis of the different phases and compared to model reanalysis data. An examination of the regional sensitivities and preliminary analysis of three locations was conducted using model reanalysis data to determine the leading convective mechanisms in these areas and how they might respond to the ENSO phases

  7. Trend Change Detection in NDVI Time Series: Effects of Inter-Annual Variability and Methodology

    Science.gov (United States)

    Forkel, Matthias; Carvalhais, Nuno; Verbesselt, Jan; Mahecha, Miguel D.; Neigh, Christopher S.R.; Reichstein, Markus

    2013-01-01

    Changing trends in ecosystem productivity can be quantified using satellite observations of Normalized Difference Vegetation Index (NDVI). However, the estimation of trends from NDVI time series differs substantially depending on analyzed satellite dataset, the corresponding spatiotemporal resolution, and the applied statistical method. Here we compare the performance of a wide range of trend estimation methods and demonstrate that performance decreases with increasing inter-annual variability in the NDVI time series. Trend slope estimates based on annual aggregated time series or based on a seasonal-trend model show better performances than methods that remove the seasonal cycle of the time series. A breakpoint detection analysis reveals that an overestimation of breakpoints in NDVI trends can result in wrong or even opposite trend estimates. Based on our results, we give practical recommendations for the application of trend methods on long-term NDVI time series. Particularly, we apply and compare different methods on NDVI time series in Alaska, where both greening and browning trends have been previously observed. Here, the multi-method uncertainty of NDVI trends is quantified through the application of the different trend estimation methods. Our results indicate that greening NDVI trends in Alaska are more spatially and temporally prevalent than browning trends. We also show that detected breakpoints in NDVI trends tend to coincide with large fires. Overall, our analyses demonstrate that seasonal trend methods need to be improved against inter-annual variability to quantify changing trends in ecosystem productivity with higher accuracy.

  8. Seasonal and inter-annual variability of energy exchange above a boreal Scots pine forest

    Directory of Open Access Journals (Sweden)

    S. Launiainen

    2010-12-01

    Full Text Available Twelve-years of eddy-covariance measurements conducted above a boreal Scots pine forest in Hyytiälä, Southern Finland, were analyzed to assess the seasonal and inter-annual variability of surface conductance (gs and energy partitioning. The gs had distinct annual course, driven by the seasonal cycle of the Scots pine. Low gs (2–3 mm s−1 in April cause the sensible heat flux to peak in May–June while evapotranspiration takes over later in July–August when gs is typically 5–7 mm s−1. Hence, during normal years Bowen ratio decreases from 4–6 in April to 0.7–0.9 in August. Sensitivity of gs to ambient vapor pressure deficit (D was relatively constant but the reference value at D = 1 kPa varied seasonally and between years. Only two drought episodes when volumetric soil moisture content in upper mineral soil decreased below 0.15 m3 m−3 occurred during the period. Below this threshold value, transpiration was strongly reduced, which promoted sensible heat exchange increasing Bowen ratio to 3–4. Annual evapotranspiration varied between 218 and 361 mm and accounted between 50% and 90% of equilibrium evaporation. The forest floor contributed between 16 and 25% of the total evapotranspiration on annual scale. The fraction stayed similar over the observed range of environmental conditions including drought periods. The inter-annual variability of evapotranspiration could not be linked to any mean climate variable while the summertime sensible heat flux and net radiation were well explained by global radiation. The energy balance closure varied annually between 0.66 and 0.95 and had a distinct seasonal cycle with worse closure in spring when a large proportion of available energy is partitioned into sensible heat.

  9. Inter-annual to multi-decadal variability in prairie water resources over the past millennium

    International Nuclear Information System (INIS)

    Sauchyn, D.

    2008-01-01

    In the Prairie Provinces, declining levels have been recently recorded for various rivers and lakes, and further reductions are projected. These trends reflect human impact in terms of increasing water consumption and possibly anthropogenic climate change. From the coupling of hydrological models and climate change scenarios, researchers have projected lower future summer flows as global warming brings shorter warmer winters and longer and generally drier summers to western Canada. However, the detection and interpretation of trends from gauge records and model outputs are constrained by the relatively short perspective of decades and the uncertainties associated with projecting climate change and its impacts on hydrological regimes. A longer perspective on inter-annual to multi-decadal variability in water resources is available from moisture-sensitive tree-ring chronologies. We have established a dense network of low elevation chronologies spanning the headwaters of the Saskatchewan, Missouri, Churchill and Mackenzie River basins. Standardized tree-ring width for a large sample of trees and sites is a strong regional signal of annual and seasonal hydroclimate, and an especially good proxy of low water levels. Proxy streamflow records, up to 800 years in length, show quasi-periodic variability at inter-annual to multi-decadal scales that correspond to the tempo of sea-surface temperature anomalies. The industrial sponsors of our research, Manitoba Hydro and EPCOR, anticipate the use of our tree-ring reconstructions for informing forecasts of future water supplies and planning adaptation to climate change. Engineers from these companies, and more than 50 other water managers and planners from the Prairie Provinces, attended a workshop in March 2008 to explore potential applications of paleo-hydrological records to water resource management. (author)

  10. Twenty years of high-resolution sea surface temperature imagery around Australia: inter-annual and annual variability.

    Science.gov (United States)

    Foster, Scott D; Griffin, David A; Dunstan, Piers K

    2014-01-01

    The physical climate defines a significant portion of the habitats in which biological communities and species reside. It is important to quantify these environmental conditions, and how they have changed, as this will inform future efforts to study many natural systems. In this article, we present the results of a statistical summary of the variability in sea surface temperature (SST) time-series data for the waters surrounding Australia, from 1993 to 2013. We partition variation in the SST series into annual trends, inter-annual trends, and a number of components of random variation. We utilise satellite data and validate the statistical summary from these data to summaries of data from long-term monitoring stations and from the global drifter program. The spatially dense results, available as maps from the Australian Oceanographic Data Network's data portal (http://www.cmar.csiro.au/geonetwork/srv/en/metadata.show?id=51805), show clear trends that associate with oceanographic features. Noteworthy oceanographic features include: average warming was greatest off southern West Australia and off eastern Tasmania, where the warming was around 0.6°C per decade for a twenty year study period, and insubstantial warming in areas dominated by the East Australian Current, but this area did exhibit high levels of inter-annual variability (long-term trend increases and decreases but does not increase on average). The results of the analyses can be directly incorporated into (biogeographic) models that explain variation in biological data where both biological and environmental data are on a fine scale.

  11. Twenty years of high-resolution sea surface temperature imagery around Australia: inter-annual and annual variability.

    Directory of Open Access Journals (Sweden)

    Scott D Foster

    Full Text Available The physical climate defines a significant portion of the habitats in which biological communities and species reside. It is important to quantify these environmental conditions, and how they have changed, as this will inform future efforts to study many natural systems. In this article, we present the results of a statistical summary of the variability in sea surface temperature (SST time-series data for the waters surrounding Australia, from 1993 to 2013. We partition variation in the SST series into annual trends, inter-annual trends, and a number of components of random variation. We utilise satellite data and validate the statistical summary from these data to summaries of data from long-term monitoring stations and from the global drifter program. The spatially dense results, available as maps from the Australian Oceanographic Data Network's data portal (http://www.cmar.csiro.au/geonetwork/srv/en/metadata.show?id=51805, show clear trends that associate with oceanographic features. Noteworthy oceanographic features include: average warming was greatest off southern West Australia and off eastern Tasmania, where the warming was around 0.6°C per decade for a twenty year study period, and insubstantial warming in areas dominated by the East Australian Current, but this area did exhibit high levels of inter-annual variability (long-term trend increases and decreases but does not increase on average. The results of the analyses can be directly incorporated into (biogeographic models that explain variation in biological data where both biological and environmental data are on a fine scale.

  12. Seasonal and inter-annual temperature variability in the bottom waters over the Black Sea shelf

    Science.gov (United States)

    Shapiro, G. I.; Wobus, F.; Aleynik, D. L.

    2011-02-01

    convection events is well preserved over the following months in the deep sea, the signal of winter cooling in the Bottom Shelf Waters significantly reduces during the warm season. The time series of temperature in the BSW is highly correlated with the temperature of Cold Intermediate Waters in the deep sea thus indicating that the isopycnal exchanges with the deep sea are more important for inter-annual/inter-decadal variability of the BSW on the Western Black Sea shelf than winter convection on the shelf itself.

  13. Inter-Annual Variability in Blue Whale Distribution off Southern Sri Lanka between 2011 and 2012

    Directory of Open Access Journals (Sweden)

    Asha de Vos

    2014-07-01

    Full Text Available Blue whale (Balaenoptera musculus movements are often driven by the availability of their prey in space and time. While globally blue whale populations undertake long-range migrations between feeding and breeding grounds, those in the northern Indian Ocean remain in low latitude waters throughout the year with the implication that the productivity of these waters is sufficient to support their energy needs. A part of this population remains around Sri Lanka where they are usually recorded close to the southern coast during the Northeast Monsoon. To investigate inter-annual variability in sighting locations, we conducted systematic Conductivity-Temperature-Depth (CTD and visual surveys between January–March 2011 and January–March 2012. In 2011, there was a notable decrease in inshore sightings compared to 2009 and 2012 (p < 0.001. CTD data revealed that in 2011 there was increased freshwater in the upper water column accompanied by deeper upwelling than in 2012. We hypothesise that anomalous rainfall, along with higher turbidity resulting from river discharge, affected the productivity of the inshore waters and caused a shift in blue whale prey and, consequently, the distribution of the whales themselves. An understanding of how predators and their prey respond to environmental variability is important for predicting how these species will respond to long-term changes. This is especially important given the rapid temperature increases predicted for the semi-enclosed northern Indian Ocean.

  14. Patterns and controls of inter-annual variability in the terrestrial carbon budget

    Directory of Open Access Journals (Sweden)

    B. Marcolla

    2017-08-01

    Full Text Available The terrestrial carbon fluxes show the largest variability among the components of the global carbon cycle and drive most of the temporal variations in the growth rate of atmospheric CO2. Understanding the environmental controls and trends of the terrestrial carbon budget is therefore essential to predict the future trajectories of the CO2 airborne fraction and atmospheric concentrations. In the present work, patterns and controls of the inter-annual variability (IAV of carbon net ecosystem exchange (NEE have been analysed using three different data streams: ecosystem-level observations from the FLUXNET database (La Thuile and 2015 releases, the MPI-MTE (model tree ensemble bottom–up product resulting from the global upscaling of site-level fluxes, and the Jena CarboScope Inversion, a top–down estimate of surface fluxes obtained from observed CO2 concentrations and an atmospheric transport model. Consistencies and discrepancies in the temporal and spatial patterns and in the climatic and physiological controls of IAV were investigated between the three data sources. Results show that the global average of IAV at FLUXNET sites, quantified as the standard deviation of annual NEE, peaks in arid ecosystems and amounts to  ∼  120 gC m−2 y−1, almost 6 times more than the values calculated from the two global products (15 and 20 gC m−2 y−1 for MPI-MTE and the Jena Inversion, respectively. Most of the temporal variability observed in the last three decades of the MPI-MTE and Jena Inversion products is due to yearly anomalies, whereas the temporal trends explain only about 15 and 20 % of the variability, respectively. Both at the site level and on a global scale, the IAV of NEE is driven by the gross primary productivity and in particular by the cumulative carbon flux during the months when land acts as a sink. Altogether these results offer a broad view on the magnitude, spatial patterns and environmental drivers of IAV

  15. Patterns and controls of inter-annual variability in the terrestrial carbon budget

    Science.gov (United States)

    Marcolla, Barbara; Rödenbeck, Christian; Cescatti, Alessandro

    2017-08-01

    The terrestrial carbon fluxes show the largest variability among the components of the global carbon cycle and drive most of the temporal variations in the growth rate of atmospheric CO2. Understanding the environmental controls and trends of the terrestrial carbon budget is therefore essential to predict the future trajectories of the CO2 airborne fraction and atmospheric concentrations. In the present work, patterns and controls of the inter-annual variability (IAV) of carbon net ecosystem exchange (NEE) have been analysed using three different data streams: ecosystem-level observations from the FLUXNET database (La Thuile and 2015 releases), the MPI-MTE (model tree ensemble) bottom-up product resulting from the global upscaling of site-level fluxes, and the Jena CarboScope Inversion, a top-down estimate of surface fluxes obtained from observed CO2 concentrations and an atmospheric transport model. Consistencies and discrepancies in the temporal and spatial patterns and in the climatic and physiological controls of IAV were investigated between the three data sources. Results show that the global average of IAV at FLUXNET sites, quantified as the standard deviation of annual NEE, peaks in arid ecosystems and amounts to ˜ 120 gC m-2 y-1, almost 6 times more than the values calculated from the two global products (15 and 20 gC m-2 y-1 for MPI-MTE and the Jena Inversion, respectively). Most of the temporal variability observed in the last three decades of the MPI-MTE and Jena Inversion products is due to yearly anomalies, whereas the temporal trends explain only about 15 and 20 % of the variability, respectively. Both at the site level and on a global scale, the IAV of NEE is driven by the gross primary productivity and in particular by the cumulative carbon flux during the months when land acts as a sink. Altogether these results offer a broad view on the magnitude, spatial patterns and environmental drivers of IAV from a variety of data sources that can be

  16. Inter-annual Variability in Tundra Phenology Captured with Digital Photography

    Science.gov (United States)

    Melendez, M.; Vargas, S. A.; Tweedie, C. E.

    2012-12-01

    The need to improve multi-scale phenological monitoring of arctic terrestrial ecosystems has been a persistent research challenge. Although there has been a range of advances in remote sensing capacities over the past decade, these present costly, and sometimes logistically challenging and technically demanding solutions for arctic terrestrial ecosystems. In this poster and undergraduate research project, we demonstrate how seasonal and inter-annual variability in landscape phenology can be derived for multiple tundra ecosystems using a low-cost and low-tech kite aerial photography (KAP) system that has been developed as a contribution to the US Arctic Observing Network. Seasonal landscape phenology was observed over the Networked Info-Mechanical Systems (NIMS) grids (2 x 50 meters) located in Barrow and Atqasuk, Alaska using imagery acquired with KAP and analyzed for a range of greenness indices. Preliminary results showed that the 2G-RB greenness index correlated the best with NDVI values calculated from ground based hyperspectral reflectance measurements. 2012 had the highest 2G-RB greenness index values for both Barrow and Atqasuk sites, which correlated well with NDVI values acquired from ground-based hyperspectral reflectance measurements. Wet vegetation types showed the most interannual variability at the Atqasuk site based on the 2G-RB greenness index while in Barrow the moist vegetation types showed the most interannual variability. These results show that vegetation indices similar to those acquired from hyperspectral remote sensing platforms can be derived using low-cost and low-tech techniques. Further analysis using these same techniques is required in order to link relatively small scale vegetation dynamics measured with KAP with those documented at large scales using satellite imagery.

  17. INTER-annual/decadal variability of the north Aegean Sea hydrodynamics over 1960-2000

    Directory of Open Access Journals (Sweden)

    V. VERVATIS

    2014-12-01

    Full Text Available Results from a high-resolution hindcast model experiment, supported by available observations, reveal an increasing salinity trend in the north Aegean during the Eastern Mediterranean Transient (EMT, largely controlled by increases in the flow rate and salinity of water masses of Levantine origin entering the domain through the Myconos-Ikaria strait as a response to an acceleration of the Aegean thermohaline cell. Changes in the Dardanelles inflow (increasing salinity and in the surface freshwater flux (increasing Evaporation-Precipitation, although both contribute to a higher salt content of the basin during the EMT, play a minor role in the inter-annual/decadal variability of the freshwater budget. A long-term decreasing temperature trend is observed from the 1960s to the early 1990s. It is superimposed on the salinity-preconditioning phase over the 1980s and early 1990s. Both signals are, concomitantly, favouring conditions for intense Dense Water Formation (DWF in the north Aegean Sea. In addition, the northward displacement of the Black Sea Water front over the EMT, leads to the expansion of convective cells towards the north and to higher formation rates associated with both colder and saltier surface waters.

  18. Inter-annual sea level variability in the southern Gulf of Mexico (1966-1976)

    Science.gov (United States)

    Salas-de-León, David Alberto; Monreal-Gómez, María Adela; Salas-Monreal, David; Riveron-Enzastiga, Mayra Lorena; Sánchez-Santillan, Norma Leticia

    2006-04-01

    Hourly time series at seven locations throughout the southern Gulf of Mexico were used to calculate the trend and the inter-annual sea level. The sea level series from January 1966 to December 1976 were filtered using a Lanczos low pass filter to remove oscillations with periods smaller than one year. The results revealed a sea level increment of about 1.4 mm yr-1 from 1966 to 1976 in the southern Gulf of Mexico. The monthly sea level variability obtained after the trends were removed, presented a sea level setup during winter and a sea level depression in summer attributed to seasonal wind conditions. The horizontal representation of averaged sea level in the southern Gulf of Mexico presented a saddle critical point. The associated sea level slope indicated water accumulation at Ciudad Madero in the western side of the gulf and Coatzacoalcos in the southernmost station, and sea level depressions at Tuxpan and Progreso in the southwestern and southeastern side of the gulf, respectively. Nevertheless, one of the most intriguing result is the presence of a Kelvin wave with a two mode oscillation axis that goes from Progreso to Tuxpan.

  19. Tropopause referenced ozone climatology and inter-annual variability (1994–2003 from the MOZAIC programme

    Directory of Open Access Journals (Sweden)

    Thouret

    2006-01-01

    Full Text Available The MOZAIC programme collects ozone and water vapour data using automatic equipment installed on board five long-range Airbus A340 aircraft flying regularly all over the world since August 1994. Those measurements made between September 1994 and August 1996 allowed the first accurate ozone climatology at 9–12 km altitude to be generated. The seasonal variability of the tropopause height has always provided a problem when constructing climatologies in this region. To remove any signal from the seasonal and synoptic scale variability in tropopause height we have chosen in this further study of these and subsequent data to reference our climatology to the altitude of the tropopause. We define the tropopause as a mixing zone 30 hPa thick across the 2 pvu potential vorticity surface. A new ozone climatology is now available for levels characteristic of the upper troposphere (UT and the lower stratosphere (LS regardless of the seasonal variations of the tropopause over the period 1994–2003. Moreover, this new presentation has allowed an estimation of the monthly mean climatological ozone concentration at the tropopause showing a sine seasonal variation with a maximum in May (120 ppbv and a minimum in November (65 ppbv. Besides, we present a first assessment of the inter-annual variability of ozone in this particular critical region. The overall increase in the UTLS is about 1%/yr for the 9 years sampled. However, enhanced concentrations about 10–15 % higher than the other years were recorded in 1998 and 1999 in both the UT and the LS. This so-called '1998–1999 anomaly' may be attributed to a combination of different processes involving large scale modes of atmospheric variability, circulation features and local or global pollution, but the most dominant one seems to involve the variability of the North Atlantic Oscillation (NAO as we find a strong positive correlation (above 0.60 between ozone recorded in the upper troposphere and the NAO

  20. The influence of intra- and inter-annual meteorological variability on dengue transmission: a multi-level modeling analysis

    Science.gov (United States)

    Wen, Tzai-Hung; Chen, Tzu-Hsin

    2017-04-01

    Dengue fever is one of potentially life-threatening mosquito-borne diseases and IPCC Fifth Assessment Report (AR5) has confirmed that dengue incidence is sensitive to the critical weather conditions, such as effects of temperature. However, previous literature focused on the effects of monthly or weekly average temperature or accumulative precipitation on dengue incidence. The influence of intra- and inter-annual meteorological variability on dengue outbreak is under investigated. The purpose of the study focuses on measuring the effect of the intra- and inter-annual variations of temperature and precipitation on dengue outbreaks. We developed the indices of intra-annual temperature variability are maximum continuity, intermittent, and accumulation of most suitable temperature (MST) for dengue vectors; and also the indices of intra-annual precipitation variability, including the measure of continuity of wetness or dryness during a pre-epidemic period; and rainfall intensity during an epidemic period. We used multi-level modeling to investigate the intra- and inter-annual meteorological variations on dengue outbreaks in southern Taiwan from 1998-2015. Our results indicate that accumulation and maximum continuity of MST are more significant than average temperature on dengue outbreaks. The effect of continuity of wetness during the pre-epidemic period is significantly more positive on promoting dengue outbreaks than the rainfall effect during the epidemic period. Meanwhile, extremely high or low rainfall density during an epidemic period do not promote the spread of dengue epidemics. Our study differentiates the effects of intra- and inter-annual meteorological variations on dengue outbreaks and also provides policy implications for further dengue control under the threats of climate change. Keywords: dengue fever, meteorological variations, multi-level model

  1. The impact of inter-annual variability of annual cycle on long-term persistence of surface air temperature in long historical records

    Science.gov (United States)

    Deng, Qimin; Nian, Da; Fu, Zuntao

    2018-02-01

    Previous studies in the literature show that the annual cycle of surface air temperature (SAT) is changing in both amplitude and phase, and the SAT departures from the annual cycle are long-term correlated. However, the classical definition of temperature anomalies is based on the assumption that the annual cycle is constant, which contradicts the fact of changing annual cycle. How to quantify the impact of the changing annual cycle on the long-term correlation of temperature anomaly variability still remains open. In this paper, a recently developed data adaptive analysis tool, the nonlinear mode decomposition (NMD), is used to extract and remove time-varying annual cycle to reach the new defined temperature anomalies in which time-dependent amplitude of annual cycle has been considered. By means of detrended fluctuation analysis, the impact induced by inter-annual variability from the time-dependent amplitude of annual cycle has been quantified on the estimation of long-term correlation of long historical temperature anomalies in Europe. The results show that the classical climatology annual cycle is supposed to lack inter-annual fluctuation which will lead to a maximum artificial deviation centering around 600 days. This maximum artificial deviation is crucial to defining the scaling range and estimating the long-term persistence exponent accurately. Selecting different scaling range could lead to an overestimation or underestimation of the long-term persistence exponent. By using NMD method to extract the inter-annual fluctuations of annual cycle, this artificial crossover can be weakened to extend a wider scaling range with fewer uncertainties.

  2. Seasonal and inter-annual variability of lower stratospheric age of air spectra

    Science.gov (United States)

    Ploeger, Felix; Birner, Thomas

    2016-08-01

    Trace gas transport in the lower stratosphere is investigated by analysing seasonal and inter-annual variations of the age of air spectrum - the probability distribution of stratospheric transit times. Age spectra are obtained using the Chemical Lagrangian Model of the Stratosphere (CLaMS) driven by ERA-Interim winds and total diabatic heating rates, and using a time-evolving boundary-impulse-response (BIER) method based on multiple tracer pulses. Seasonal age spectra show large deviations from an idealized stationary uni-modal shape. Multiple modes emerge in the spectrum throughout the stratosphere, strongest at high latitudes, caused by the interplay of seasonally varying tropical upward mass flux, stratospheric transport barriers and recirculation. Inter-annual variations in transport (e.g. quasi-biennial oscillation) cause significant modulations of the age spectrum shape. In fact, one particular QBO phase may determine the spectrum's mode during the following 2-3 years. Interpretation of the age spectrum in terms of transport contributions due to the residual circulation and mixing is generally not straightforward. It turns out that advection by the residual circulation represents the dominant pathway in the deep tropics and in the winter hemisphere extratropics above 500 K, controlling the modal age in these regions. In contrast, in the summer hemisphere, particularly in the lowermost stratosphere, mixing represents the most probable pathway controlling the modal age.

  3. Capturing Inter-Annual Variability of PV Energy Production in South Asia

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Anthony [National Renewable Energy Lab. (NREL), Golden, CO (United States); Maclaurin, Galen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Roberts, Billy [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rosenlieb, Evan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-08-25

    Long-term variability of solar resource is an important factor in planning a utility-scale photovoltaic (PV) generation plant, and annual generation for a given location can vary significantly from year to year. Based on multiple years of solar irradiance data, an exceedance probability is the amount of energy that could potentially be produced by a power plant in any given year. An exceedance probability accounts for long-term variability and climate cycles (e.g., monsoons or changes in aerosols), which ultimately impact PV energy generation. Study results indicate that a significant bias could be associated with relying solely on typical meteorological year (TMY) resource data to capture long-term variability. While the TMY tends to under-predict annual generation overall compared to the P50, there appear to be pockets of over-prediction as well.

  4. Inter-annual variability in fossil-fuel CO2 emissions due to temperature anomalies

    Science.gov (United States)

    Bréon, F.-M.; Boucher, O.; Brender, P.

    2017-07-01

    It is well known that short-term (i.e. interannual) variations in fossil-fuel CO2 emissions are closely related to the evolution of the national economies. Nevertheless, a fraction of the CO2 emissions are linked to domestic and business heating and cooling, which can be expected to be related to the meteorology, independently of the economy. Here, we analyse whether the signature of the inter-annual temperature anomalies is discernible in the time series of CO2 emissions at the country scale. Our analysis shows that, for many countries, there is a clear positive correlation between a heating-degree-person index and the component of the CO2 emissions that is not explained by the economy as quantified by the gross domestic product (GDP). Similarly, several countries show a positive correlation between a cooling-degree-person (CDP) index and CO2 emissions. The slope of the linear relationship for heating is on the order of 0.5-1 kg CO2 (degree-day-person)-1 but with significant country-to-country variations. A similar relationship for cooling shows even greater diversity. We further show that the inter-annual climate anomalies have a small but significant impact on the annual growth rate of CO2 emissions, both at the national and global scale. Such a meteorological effect was a significant contribution to the rather small and unexpected global emission growth rate in 2014 while its contribution to the near zero emission growth in 2015 was insignificant.

  5. The climatic variability inter annual associated to El Nino - la Nina cycle, oscillation of the south and their effect in the pluviometric patron of Colombia

    International Nuclear Information System (INIS)

    Montealegre Bocanegra Jose Edgar; Pabon Caicedo, Jose Daniel

    2000-01-01

    In the present article we study the influence that on a year-to-year scale the interactions between the atmosphere and the Tropical North and South Atlantic, as well as the Pacific Ocean, have on the inter annual variability of the precipitation in Colombia. We identify and quantify the existing relations between the indexes of the macro-scale, characteristic of the inter annual variability of those oceans, and the indexes characteristic of the inter annual precipitation variability, for selected regions in Colombia. The determination of these relations is of fundamental importance in order to develop objective schemes, based on physic-statistical methods, aimed at predicting the climate in Colombia

  6. Inter-annual variabilities in biogeophysical feedback of terrestrial ecosystem to atmosphere using a land surface model

    Science.gov (United States)

    Seo, C.; Hong, S.; Jeong, H. M.; Jeon, J.

    2017-12-01

    Biogeophysical processes of terrestrial ecosystem such as water vapor and energy flux are the key features to understand ecological feedback to atmospheric processes and thus role of terrestrial ecosystem in climate system. For example, it has been recently known that the ecological feedback through water vapor and energy flux results in regulating regional weathers and climates which is one of the fundamental functions of terrestrial ecosystem. In regional scale, water vapor flux has been known to give negative feedback to atmospheric warming, while energy flux from the surface has been known to positive feedback. In this study, we explored the inter-annual variabilities in these two biogeophysical features to see how the climate regulating functions of terrestrial ecosystem have been changed with climate change. We selected a land surface model involving vegetation dynamics that is forced by atmospheric data from NASA including precipitation, temperature, wind, surface pressure, humidity, and incoming radiations. From the land surface model, we simulated 60-year water vapor and energy fluxes from 1961 to 2010, and calculates feedbacks of terrestrial ecosystem as in radiation amount into atmosphere. Then, we analyzed the inter-annual variabilities in the feedbacks. The results showed that some mid-latitude areas showing very high variabilities in precipitation showed higher positive feedback and/or lower negative feedback. These results suggest deterioration of the biogeophyisical factor of climate regulating function over those regions.

  7. Estimating inter-annual variability in winter wheat sowing dates from satellite time series in Camargue, France

    Science.gov (United States)

    Manfron, Giacinto; Delmotte, Sylvestre; Busetto, Lorenzo; Hossard, Laure; Ranghetti, Luigi; Brivio, Pietro Alessandro; Boschetti, Mirco

    2017-05-01

    Crop simulation models are commonly used to forecast the performance of cropping systems under different hypotheses of change. Their use on a regional scale is generally constrained, however, by a lack of information on the spatial and temporal variability of environment-related input variables (e.g., soil) and agricultural practices (e.g., sowing dates) that influence crop yields. Satellite remote sensing data can shed light on such variability by providing timely information on crop dynamics and conditions over large areas. This paper proposes a method for analyzing time series of MODIS satellite data in order to estimate the inter-annual variability of winter wheat sowing dates. A rule-based method was developed to automatically identify a reliable sample of winter wheat field time series, and to infer the corresponding sowing dates. The method was designed for a case study in the Camargue region (France), where winter wheat is characterized by vernalization, as in other temperate regions. The detection criteria were chosen on the grounds of agronomic expertise and by analyzing high-confidence time-series vegetation index profiles for winter wheat. This automatic method identified the target crop on more than 56% (four-year average) of the cultivated areas, with low commission errors (11%). It also captured the seasonal variability in sowing dates with errors of ±8 and ±16 days in 46% and 66% of cases, respectively. Extending the analysis to the years 2002-2012 showed that sowing in the Camargue was usually done on or around November 1st (±4 days). Comparing inter-annual sowing date variability with the main local agro-climatic drivers showed that the type of preceding crop and the weather conditions during the summer season before the wheat sowing had a prominent role in influencing winter wheat sowing dates.

  8. Drivers of inter-annual variability in Net Ecosystem Exchange in a semi-arid savanna ecosystem, South Africa

    Directory of Open Access Journals (Sweden)

    S. A. Archibald

    2009-02-01

    Full Text Available Inter-annual variability in primary production and ecosystem respiration was explored using eddy-covariance data at a semi-arid savanna site in the Kruger Park, South Africa. New methods of extrapolating night-time respiration to the entire day and filling gaps in eddy-covariance data in semi-arid systems were developed. Net ecosystem exchange (NEE in these systems occurs as pulses associated with rainfall events, a pattern not well-represented in current standard gap-filling procedures developed primarily for temperate flux sites. They furthermore do not take into account the decrease in respiration at high soil temperatures. An artificial neural network (ANN model incorporating these features predicted measured fluxes accurately (MAE 0.42 gC/m2/day, and was able to represent the seasonal patterns of photosynthesis and respiration at the site. The amount of green leaf area (indexed using satellite-derived estimates of fractional interception of photosynthetically active radiation fAPAR, and the timing and magnitude of rainfall events, were the two most important predictors used in the ANN model. These drivers were also identified by multiple linear regressions (MLR, with strong interactive effects. The annual integral of the filled NEE data was found to range from −138 to +155 g C/m2/y over the 5 year eddy covariance measurement period. When applied to a 25 year time series of meteorological data, the ANN model predicts an annual mean NEE of 75(±105 g C/m2/y. The main correlates of this inter-annual variability were found to be variation in the amount of absorbed photosynthetically active radiation (APAR, length of the growing season, and number of days in the year when moisture was available in the soil.

  9. Trends and inter-annual variability of methane emissions derived from 1979-1993 global CTM simulations

    Directory of Open Access Journals (Sweden)

    F. Dentener

    2003-01-01

    Full Text Available The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistry-transport model. Our semi-inverse analysis uses the fifteen years (1979--1993 re-analysis of ECMWF meteorological data and annually varying emissions including photo-chemistry, in conjunction with observed CH4 concentration distributions and trends derived from the NOAA-CMDL surface stations. Dividing the world in four zonal regions (45--90 N, 0--45 N, 0--45 S, 45--90 S we find good agreement in each region between (top-down calculated emission trends from model simulations and (bottom-up estimated anthropogenic emission trends based on the EDGAR global anthropogenic emission database, which amounts for the period 1979--1993 2.7 Tg CH4 yr-1. Also the top-down determined total global methane emission compares well with the total of the bottom-up estimates. We use the difference between the bottom-up and top-down determined emission trends to calculate residual emissions. These residual emissions represent the inter-annual variability of the methane emissions. Simulations have been performed in which the year-to-year meteorology, the emissions of ozone precursor gases, and the stratospheric ozone column distribution are either varied, or kept constant. In studies of methane trends it is most important to include the trends and variability of the oxidant fields. The analyses reveals that the variability of the emissions is of the order of 8Tg CH4 yr-1, and likely related to wetland emissions and/or biomass burning.

  10. Seasonal and inter-annual temperature variability in the bottom waters over the western Black Sea shelf

    Directory of Open Access Journals (Sweden)

    G. I. Shapiro

    2011-09-01

    Full Text Available Long-term changes in the state of the Bottom Shelf Water (BSW on the Western shelf of the Black Sea are assessed using analysis of intra-seasonal and inter-annual temperature variations. For the purpose of this study the BSW is defined as such shelf water mass between the seabed and the upper mixed layer (bounded by the σθ = 14.2 isopycnal which has limited ability to mix vertically with oxygen-rich surface waters during the warm season due to formation of a seasonal pycnocline. A long-term time series of temperature anomalies in the BSW is constructed from in-situ observations taken over the 2nd half of the 20th century. The BSW is shown to occupy nearly half of the shelf area during the summer stratification period (May–November.The results reveal a warm phase in the 1960s/70s, followed by a cold phase between 1985 and 1995 and a further warming after 1995. The transition between the warm and cold periods coincides with a regime shift in the Black Sea ecosystem. While it was confirmed that the memory of winter convection is well preserved over the following months in the deep sea, the signal of winter cooling in the BSW significantly reduces during the warm season. The potential of the BSW to ventilate horizontally during the warm season with the deep-sea waters is assessed using isopycnic analysis of temperature variations. It is shown that temperature in the BSW is stronger correlated with the temperature of Cold Intermediate Waters (CIW in the deep sea than with the severity of the previous winters, thus indicating that the isopycnal exchanges with the deep sea are more important for inter-annual/inter-decadal variability of the BSW on the western Black Sea shelf than effects of winter convection on the shelf itself.

  11. Intra-seasonal and Inter-annual variability of Bowen Ratio over rain-shadow region of North peninsular India

    Science.gov (United States)

    Morwal, S. B.; Narkhedkar, S. G.; Padmakumari, B.; Maheskumar, R. S.; Deshpande, C. G.; Kulkarni, J. R.

    2017-05-01

    Intra-seasonal and inter-annual variability of Bowen Ratio (BR) have been studied over the rain-shadow region of north peninsular India during summer monsoon season. Daily grid point data of latent heat flux (LHF), sensible heat flux (SHF) from NCEP/NCAR Reanalysis for the period 1970-2014 have been used to compute daily area-mean BR. Daily grid point rainfall data at a resolution of 0.25° × 0.25° from APHRODITE's Water Resources for the available period 1970-2007 have been used to study the association between rainfall and BR. The study revealed that BR rapidly decreases from 4.1 to 0.29 in the month of June and then remains nearly constant at the same value (≤0.1) in the rest of the season. High values of BR in the first half of June are indicative of intense thermals and convective clouds with higher bases. Low values of BR from July to September period are indicative of weak thermals and convective clouds with lower bases. Intra-seasonal and inter-annual variability of BR is found to be inversely related to precipitation over the region. BR analysis indicates that the land surface characteristics of the study region during July-September are similar to that over oceanic regions as far as intensity of thermals and associated cloud microphysical properties are concerned. Similar variation of BR is found in El Nino and La Nina years. During June, an increasing trend is observed in SHF and BR and decreasing trend in LHF from 1976 to 2014. Increasing trend in the SHF is statistically significant.

  12. Using Decision Trees to Examine Relationships between Inter-Annual Vegetation Variability, Topographic Attributes, and Climate Signals

    Science.gov (United States)

    White, A. B.; Kumar, P.

    2003-12-01

    The objective of this research is to develop KDD (knowledge discovery in databases) techniques for spatio-temporal geo-data, and use these techniques to examine inter-annual vegetation health signals. The underlying hypothesis of the research is that the signatures of inter-annual variability of climate on vegetation dynamics as represented by the statistical descriptors of vegetation index variations depend upon a variety of attributes related to the topography, hydrology, physiography, and climate. NDVI (normalized differential vegetation index) is enlisted to represent vegetation health and relationships between this index and topographic attributes such as elevation, slope, aspect, compound topographic index (CTI), and the proximity to a stream, are analyzed. Several scientific questions related to the identification and characterization of the inter-annual variability ensue as a consequence of our hypothesis. Investigations were performed using 13 years of 1-km resolution NDVI data from the AVHRR instrument on NOAA's POES (polar-orbiting operational environmental satellite) over the continental U.S. Various temporal change indices were used in order to identify anomalous inter-annual behavior in the NDVI index, including maximum absolute and relative deviations from the 13-year mean and positive and negative persistence indices (after Zhou et al., 2001). The KDD technique used in this research is the decision tree, which falls under the classification and prediction division of data mining techniques. The algorithm is similar to c4.5 and id3, but can handle continuous input and output values without binning and is optimized to determine the minimum error. Future work will incorporate clustering algorithms (both distance and density-based) and association rule algorithms (constraint-based) adapted for spatial-temporal data. Investigations will also be performed at smaller spatial scales, integrating higher resolution data. Throughout the growing season

  13. Effects of Climatic Factors and Ecosystem Responses on the Inter-Annual Variability of Evapotranspiration in a Coniferous Plantation in Subtropical China

    Science.gov (United States)

    Xu, Mingjie; Wen, Xuefa; Wang, Huimin; Zhang, Wenjiang; Dai, Xiaoqin; Song, Jie; Wang, Yidong; Fu, Xiaoli; Liu, Yunfen; Sun, Xiaomin; Yu, Guirui

    2014-01-01

    Because evapotranspiration (ET) is the second largest component of the water cycle and a critical process in terrestrial ecosystems, understanding the inter-annual variability of ET is important in the context of global climate change. Eight years of continuous eddy covariance measurements (2003–2010) in a subtropical coniferous plantation were used to investigate the impacts of climatic factors and ecosystem responses on the inter-annual variability of ET. The mean and standard deviation of annual ET for 2003–2010 were 786.9 and 103.4 mm (with a coefficient of variation of 13.1%), respectively. The inter-annual variability of ET was largely created in three periods: March, May–June, and October, which are the transition periods between seasons. A set of look-up table approaches were used to separate the sources of inter-annual variability of ET. The annual ETs were calculated by assuming that (a) both the climate and ecosystem responses among years are variable (Vcli-eco), (b) the climate is variable but the ecosystem responses are constant (Vcli), and (c) the climate is constant but ecosystem responses are variable (Veco). The ETs that were calculated under the above assumptions suggested that the inter-annual variability of ET was dominated by ecosystem responses and that there was a negative interaction between the effects of climate and ecosystem responses. These results suggested that for long-term predictions of water and energy balance in global climate change projections, the ecosystem responses must be taken into account to better constrain the uncertainties associated with estimation. PMID:24465610

  14. INTER-EXAMINER VARIABILITY

    African Journals Online (AJOL)

    Objective: To establish whether inter-examiner variability is still a significant factor for the undergraduate orthopaedic clinical ... D. The scores for each student were tabulated and the range, mean, and pass rate determined for each of the examiners. ... has not the heart to reject the man”, consistently gave higher scores (1).

  15. Seasonal and inter-annual variability of the net ecosystem CO2 exchange of a temperate mountain grassland: effects of climate and management.

    Science.gov (United States)

    Wohlfahrt, Georg; Hammerle, Albin; Haslwanter, Alois; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander

    2008-04-27

    The role and relative importance of climate and cutting for the seasonal and inter-annual variability of the net ecosystem CO 2 (NEE) of a temperate mountain grassland was investigated. Eddy covariance CO 2 flux data and associated measurements of the green area index and the major environmental driving forces acquired during 2001-2006 at the study site Neustift (Austria) were analyzed. Driven by three cutting events per year which kept the investigated grassland in a stage of vigorous growth, the seasonal variability of NEE was primarily modulated by gross primary productivity (GPP). The role of environmental parameters in modulating the seasonal variability of NEE was obscured by the strong response of GPP to changes in the amount of green area, as well as the cutting-mediated decoupling of phenological development and the seasonal course of climate drivers. None of the climate and management metrics examined was able to explain the inter-annual variability of annual NEE. This is thought to result from (1) a high covariance between GPP and ecosystem respiration (R eco ) at the annual time scale which results in a comparatively small inter-annual variation of NEE, (2) compensating effects between carbon exchange during and outside the management period, and (3) changes in the biotic response to rather than the climate variables per se. GPP was more important in modulating inter-annual variations in NEE in spring and before the first and second cut, while R eco explained a larger fraction of the inter-annual variability of NEE during the remaining, in particular the post-cut, periods.

  16. ENSO-induced inter-annual sea level variability in the Singapore strait

    Digital Repository Service at National Institute of Oceanography (India)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    Sea level data from four tide gauge stations in the SS (Tanjong Pagar, Sultan Shoal, Sembawang and Raffles Lighthouse) for the period 1970-2012 were extracted to study the ENSO-induced interannual sea level variability Sea level during this period...

  17. Climate drives inter-annual variability in probability of high severity fire occurrence in the western United States

    Science.gov (United States)

    Keyser, Alisa; Westerling, Anthony LeRoy

    2017-05-01

    A long history of fire suppression in the western United States has significantly changed forest structure and ecological function, leading to increasingly uncharacteristic fires in terms of size and severity. Prior analyses of fire severity in California forests showed that time since last fire and fire weather conditions predicted fire severity very well, while a larger regional analysis showed that topography and climate were important predictors of high severity fire. There has not yet been a large-scale study that incorporates topography, vegetation and fire-year climate to determine regional scale high severity fire occurrence. We developed models to predict the probability of high severity fire occurrence for the western US. We predict high severity fire occurrence with some accuracy, and identify the relative importance of predictor classes in determining the probability of high severity fire. The inclusion of both vegetation and fire-year climate predictors was critical for model skill in identifying fires with high fractional fire severity. The inclusion of fire-year climate variables allows this model to forecast inter-annual variability in areas at future risk of high severity fire, beyond what slower-changing fuel conditions alone can accomplish. This allows for more targeted land management, including resource allocation for fuels reduction treatments to decrease the risk of high severity fire.

  18. Climatic Effects on the Inter-Annual Variability of Carbon Fluxes for North America and Europe

    Science.gov (United States)

    Tomelleri, E.; Carvalhais, N.; Migliavacca, M.; Reichstein, M.; Fluxnet Lathuille Synthesis Team (Cf. Www. Fluxdata. Org)

    2010-12-01

    The connection between climate variability and global carbon cycle has already been shown to be linked with the North Atlantic Oscillation (NAO) (1). A positive phase of the NAO is associated with more and stronger winter storms crossing the North Atlantic on a more northerly route, causing major anomalies in sea surface temperature, currents and convective activity throughout the North Atlantic. A long-term trend towards very positive values has culminated in the early 1990s, and since then a decreasing trend is happening (1). Identification of the climatic drivers of the net ecosystem fluxes is becoming a rising issue. In particular the effects of year-to-year climate variability on regional budgets and the understanding of the underlying biogeochemical processes are of fundamental importance due to the intensification of extreme climatic events like precipitation (2) and drought events (3). We identified the relations between climatic variability (i.e. NAO) and the regional carbon budgets of North America and Europe over the period from 1989 to 2008. In doing this we kept special focus both on temporal and spatial scale. For this purpose we took advantage of the high-density of FLUXNET measurement sites in these areas. We applied a radiation use efficiency model for gross primary production (4) combined with a semi-empirical total ecosystem respiration model (5). As drivers for the model we used climatic and fraction of absorbed photosynthetically active radiation (FPAR) records. We utilized in-situ calibrated model parameters to estimate the regional ecosystem carbon fluxes. The model was spatially applied according to the similarity in the climatic-phenological space of each grid pixel with the measurement site to which it was calibrated (e.g., 6). We found that for Europe NAO could explain NEE variability in a reasonable way for northern and southern Europe, but for the mid-latitude region this was not the case. For North America the patterns were less clear

  19. Inter-annual variability and trend detection of urban CO2, CH4 and CO emissions

    Science.gov (United States)

    Lauvaux, T.; Deng, A.; Gurney, K. R.; Nathan, B.; Ye, X.; Oda, T.; Karion, A.; Hardesty, M.; Harvey, R. M.; Richardson, S.; Whetstone, J. R.; Hutyra, L.; Davis, K. J.; Brewer, A.; Gaudet, B. J.; Turnbull, J. C.; Sweeney, C.; Shepson, P. B.; Miles, N.; Bonin, T.; Wu, K.; Balashov, N. V.

    2017-12-01

    The Indianapolis Flux (INFLUX) Experiment has conducted an unprecedented volume of atmospheric greenhouse gas measurements across the Indianapolis metropolitan area from aircraft, remote-sensing, and tower-based observational platforms. Assimilated in a high-resolution urban inversion system, atmospheric data provide an independent constraint to existing emission products, directly supporting the integration of economic data into urban emission systems. We present here the first multi-year assessment of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) emissions from anthropogenic activities in comparison to multiple bottom-up emission products. Biogenic CO2 fluxes are quantified using an optimized biogeochemical model at high resolution, further refined within the atmospheric inversion system. We also present the first sector-based inversion by jointly assimilating CO2 and CO mixing ratios to quantify the dominant sectors of emissions over the entire period (2012-2015). The detected trend in CO2 emissions over 2012-2015 from both bottom-up emission products and tower-based inversions agree within a few percent, with a decline in city emissions over the 3-year time period. Major changes occur at the primary power plant, suggesting a decrease in energy production within the city limits. The joint assimilation of CO2 and CO mixing ratios confirms the absence of trends in other sectors. However, top-down and bottom-up approaches tend to disagree annually, with a decline in urban emissions suggested by atmospheric data in 2014 that is several months earlier than is observed in the bottom-up products. Concerning CH4 emissions, the inversion shows a decrease since mid-2014 which may be due to lower landfill emissions or lower energy consumption (from coal and natural gas). This first demonstration of a high-accuracy long-term greenhouse gas measurement network merged with a high-resolution bottom-up information system highlights the potential for informing

  20. Factors affecting the inter-annual to centennial timescale variability of Indian summer monsoon rainfall

    Science.gov (United States)

    Malik, Abdul; Brönnimann, Stefan

    2017-09-01

    The Modes of Ocean Variability (MOV) namely Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and El Niño Southern Oscillation (ENSO) can have significant impacts on Indian Summer Monsoon Rainfall (ISMR) on different timescales. The timescales at which these MOV interacts with ISMR and the factors which may perturb their relationship with ISMR need to be investigated. We employ De-trended Cross-Correlation Analysis (DCCA), and De-trended Partial-Cross-Correlation Analysis (DPCCA) to study the timescales of interaction of ISMR with AMO, PDO, and ENSO using observational dataset (AD 1854-1999), and atmosphere-ocean-chemistry climate model simulations with SOCOL-MPIOM (AD 1600-1999). Further, this study uses De-trended Semi-Partial Cross-Correlation Analysis (DSPCCA) to address the relation between solar variability and the ISMR. We find statistically significant evidence of intrinsic correlations of ISMR with AMO, PDO, and ENSO on different timescales, consistent between model simulations and observations. However, the model fails to capture modulation in intrinsic relationship between ISRM and MOV due to external signals. Our analysis indicates that AMO is a potential source of non-stationary relationship between ISMR and ENSO. Furthermore, the pattern of correlation between ISMR and Total Solar Irradiance (TSI) is inconsistent between observations and model simulations. The observational dataset indicates statistically insignificant negative intrinsic correlation between ISMR and TSI on decadal-to-centennial timescales. This statistically insignificant negative intrinsic correlation is transformed to statistically significant positive extrinsic by AMO on 61-86-year timescale. We propose a new mechanism for Sun-monsoon connection which operates through AMO by changes in summer (June-September; JJAS) meridional gradient of tropospheric temperatures (ΔTTJJAS). There is a negative (positive) intrinsic correlation between ΔTTJJAS (AMO) and

  1. The Physical Context of Seasonal and Inter-Annual Variability in Phytoplankton across the Scotian Shelf: Insights from Profiling Gliders

    Science.gov (United States)

    Ross, T.; Craig, S. E.; Dever, M.; Beck, M.; Comeau, A.; Davis, R. F.

    2016-02-01

    Understanding how phytoplankton respond to their physical environment is key to predicting how bloom dynamics might change under future climate change scenarios. Phytoplankton are at the base of most marine food webs and play an important role in drawing CO2 out of the atmosphere. We use 5 years of simultaneous CTD, irradiance, fluorescence by chlorophyll a and optical backscattering observations obtained from Slocum glider missions across the Scotian Shelf, near Halifax, Nova Scotia, Canada, to examine the seasonal and inter-annual variability in proxies of phytoplankton abundance and type, and their physical context. Consistent with previous studies, we find that the main spring bloom occurs before the onset of the seasonal stratified layer. In fact, the largest chlorophyll observations consistently occurred while there was very little stratification in the upper 60 meters. This first bloom type, which was diatom dominated, was followed by a phytoplankton assemblage dominated by pico- and nano-phytoplankton and dinoflagellates associated with the nutrient poor, more stable summertime conditions. We examine the conditions throughout the entire growing season and compare the conditions during the initiation of the spring diatom bloom between years.

  2. Trends and inter-annual variability of methane emissions derived from 1979-1993 global CTM simulations

    NARCIS (Netherlands)

    Dentener, F; van Weele, M; Krol, M; Houweling, S; van Velthoven, P

    2003-01-01

    The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistry-transport model. Our semi-inverse analysis uses the fifteen years (1979-1993) re-analysis of ECMWF meteorological data and annually varying

  3. Analysis on inter-annual variability of CO2 exchange in Arctic tundra: a model-data approach

    Science.gov (United States)

    López Blanco, E.; Lund, M.; Christensen, T. R.; Smallman, T. L.; Slevin, D.; Westergaard-Nielsen, A.; Tamstorf, M. P.; Williams, M.

    2017-12-01

    Arctic ecosystems are exposed to rapid changes triggered by the climate variability, thus there is a growing concern about how the carbon (C) exchange balance will respond to climate change. There is a lack of knowledge about the mechanisms that drive the interactions between photosynthesis and ecological respiration with changes in C stocks in the Arctic tundra across full annual cycles. The reduction of uncertainties can be addressed through process-based modelling efforts. Here, we report the independent predictions of net ecosystem exchange (NEE), gross primary production (GPP) and ecosystem respiration (Reco) calculated from the soil-plant-atmosphere (SPA) model across eight years. The model products are validated with observational data obtained from the Greenland Ecosystem Monitoring (GEM) program in West Greenland tundra (64° N). Overall, the model results explain 71%, 73% and 51% of the variance in NEE, GPP and Reco respectively using data on meteorology and local vegetation and soil structure. The estimated leaf area index (LAI) is able to explain 80% of the plant greenness variation, which was used as a plant phenology proxy. The full annual cumulated NEE during the 2008-2015 period was -0.13 g C m-2 on average (range -30.6 to 34.1 g C m-2), while GPP was -214.6 g C m-2 (-126.2 to -332.8 g C m-2) and Reco was 214.4 g C m-2 (213.9 to 302.2 g C m-2). We found that the model supports the main finding from our previous analysis on flux responses to meteorological variations and biological disturbance. Here, large inter-annual variations in GPP and Reco are also compensatory, and so NEE remains stable across climatically diverse snow-free seasons. Further, we note evidence that leaf maintenance and root growth respiration are highly correlated with GPP (R2 = 0.92 and 0.83, p budgets and the delayed effect of wintertime conditions on the C fluxes.

  4. Seasonal and inter-annual turbidity variability in the Río de la Plata from 15 years of MODIS: El Niño dilution effect

    Science.gov (United States)

    Dogliotti, A. I.; Ruddick, K.; Guerrero, R.

    2016-12-01

    Spatio-temporal variability of turbidity in the Río de la Plata (RdP) estuary (Argentina) at seasonal and inter-annual timescales is analyzed from 15 years (2000-2014) of MODIS data and explained in terms of river discharges and the El Niño Southern Oscillation (ENSO). Satellite estimates were first validated using in situ turbidity measurements and then the time series of monthly averages were analyzed to assess the seasonal and inter-annual variability of turbidity. A strong seasonal variability was found in the upper and middle estuary with high turbidity from March to May and low turbidity from June to January. It was found that this variability is highly correlated to the seasonal cycle of the water discharge of the Bermejo river with a one-month delay between its peak and turbidity in the upper RdP estuary. On inter-annual time scales the influence of ENSO shows low turbidity amplitudes in the upper and middle estuary during moderate El Niño years, while the opposite pattern is observed in some La Niña years. A dilution effect during El Niño years is observed given that the main tributaries, which provide ∼92% of the liquid discharge, show water discharge increases due to excess in rain, while the Bermejo river, which provides ∼70% of the solid discharge and only 2% of the liquid discharge to the RdP, does not show this inter-decadal periodicity. In turn, increased turbidities are observed when negative RdP water discharge anomalies occurred, but this is not always related to La Niña events, since these events are not the only predictor for drought in this region.

  5. A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink

    Science.gov (United States)

    Landschützer, P.; Gruber, N.; Bakker, D. C. E.; Schuster, U.; Nakaoka, S.; Payne, M. R.; Sasse, T.; Zeng, J.

    2013-05-01

    equator (-0.007 Pg C yr-1 decade-1). Surface ocean pCO2 was also increasing less than that of the atmosphere over most of the Atlantic south of the equator, leading to a substantial trend toward a stronger CO2 sink for the entire South Atlantic (-0.14 Pg C yr-1 decade-1). The Atlantic carbon sink varies relatively little on inter-annual time-scales (±0.04 Pg C yr-1; 1σ).

  6. Influence of inter-annual environmental variability on chrysophyte cyst assemblages: insight from a 2-years sediment trap study in lakes from northern Poland

    Directory of Open Access Journals (Sweden)

    Iván Hernández-Almeida

    2017-02-01

    Full Text Available Quantitative paleonvironmental studies using transfer functions are developed from training sets. However, changes in some variables (e.g., climatic can be difficult to identify from short-term monitoring (e.g., less than one year. Here, we present the study of the chrysophyte cyst assemblages from sediment traps deployed during two consecutive years (November 2011-November 2013 in 14 lakes from Northern Poland. The studied lakes are distributed along a W-E climatological gradient, with very different physical, chemical and morphological characteristics, and land-uses. Field surveys were carried out to recover the sediment trap material during autumn, along with the measurement of several environmental variables (nutrients, major water ions, conductivity, pH, dissolved oxygen and chlorophyll-a. During the study, one year experienced mild seasonal changes in air temperature (November 2011-November 2012; TS1, typical of oceanic climate, while the other year was characterized by colder winter and spring (November 2012-November 2013; TS2, and higher summer temperatures, more characteristic of continental climate. Other environmental variables (e.g., nutrients did not show great changes between both years. Multivariate statistical analyses (RDA and DCA were performed on individual TS1 and TS2 datasets. Water chemistry and nutrients (pH, TN and TP explained the largest portion of the variance of the chrysophyte data for the individual years. However, analyses of the combined TS1 and TS2 datasets show that strong changes between summer and autumn (warm period, ice-free period with thermal stratification and winter and spring (cold period, ice-cover period play the most important role in the inter-annual variability in the chrysophyte assemblages. We show how inter-annual sampling maximizes ecological gradients of interest, particularly in regions with large environmental diversity, and low climatic variability. This methodology could help to identify

  7. Seasonal and inter-annual variability of sea surface temperature at the east coast fishing area off Peninsular Malaysia

    Science.gov (United States)

    Nurul Ridani, S.; Mustapha, M. A.; Lihan, T.; Ku Kassim, K. Y.; Raja Bidin, R. H.

    2015-09-01

    Empirical orthogonal function (EOF) analysis was used to study a time-series of the aqua MODIS data imageries in the exclusive economic zone of east coast off Peninsular Malaysia. Temporal and spatial characteristics were examined to determine the dominant pattern of sea surface temperature (SST) variability from January 2003 to December 2011.The data were analysed from daily Level 1A (1km spatial resolution) to monthly composites Level 3 data using SeaDAS and ERDAS imagine software. Four modes was obtained from the analysis with the highest variance (7.9%) represented by mode 1 which explained the seasonal cycle. Mode 2 (5.11 % of total variance) showed positive and negative peak signal during March and April and in October and November with variability near the Kelantan and Pahang waters that indicated the inter monsoon. Mode 3 (3.8 % of variance) shows variability near the Terengganu, Kelantan and Johor waters to the open sea during July and August and in May and June representing the Southwest monsoon. Mode 4 (3.36 %) showed positive signal during November and December with strong signal near Pahang and Kelantan waters while weak signal was detected near Terengganu and Kelantan's open sea representing the Northeast monsoon. The SST variability was influenced by the monsoonal system which originated by the wind forcing condition that influences circulation in the study area.

  8. Explaining the inter-annual variability in the ecosystem fluxes of the Brasschaat Scots pine forest: 20 years of eddy flux and pollution monitoring

    Science.gov (United States)

    Horemans, Joanna; Roland, Marilyn; Janssens, Ivan; Ceulemans, Reinhart

    2017-04-01

    Because of their ecological and recreational value, the health of forest ecosystems and their response to global change and pollution are of high importance. At a number of EuroFlux and ICOS ecosystem sites in Europe - as the Brasschaat forest site - the measurements of ecosystem fluxes of carbon and other gases are combined with vertical profiles of air pollution within the framework of the ICP-Forest monitoring program. The Brasschaat forest is dominated by 80-year old Scots pines (Pinus sylvestris L.), and has a total area of about 150 ha. It is situated near an urban area in the Campine region of Flanders, Belgium and is characterized by a mean annual temperature of 9.8 °C and an annual rainfall of 830 mm. In this contribution we report on a long-term analysis (1996-2016) of the ecosystem carbon and water fluxes, the energy exchanges and the pollutant concentrations (ozone, NOx, NH3, SO2). Particular interest goes to the inter-annual variation of the carbon fluxes and the carbon allocation patterns. The impact of the long-term (aggregated) and the short-term variability in both the meteorological drivers and in the main tropospheric pollutants on the carbon fluxes is examined, as well as their mutual interactive effects and their potential memory effect. The effect of variability in the drivers during the phenological phases (seasonality) on the inter-annual variability of the fluxes is also examined. Basic statistical techniques as well as spectral analyses and data mining techniques are being used.

  9. Root-associated fungi of Vaccinium carlesii in subtropical forests of China: intra- and inter-annual variability and impacts of human disturbances

    Science.gov (United States)

    Zhang, Yanhua; Ni, Jian; Tang, Fangping; Pei, Kequan; Luo, Yiqi; Jiang, Lifen; Sun, Lifu; Liang, Yu

    2016-01-01

    Ericoid mycorrhiza (ERM) are expected to facilitate establishment of ericaceous plants in harsh habitats. However, diversity and driving factors of the root-associated fungi of ericaceous plants are poorly understood. In this study, hair-root samples of Vaccinium carlesii were taken from four forest types: old growth forests (OGF), secondary forests with once or twice cutting (SEC I and SEC II), and Cunninghamia lanceolata plantation (PLF). Fungal communities were determined using high-throughput sequencing, and impacts of human disturbances and the intra- and inter-annual variability of root-associated fungal community were evaluated. Diverse fungal taxa were observed and our results showed that (1) Intra- and inter-annual changes in root-associated fungal community were found, and the Basidiomycota to Ascomycota ratio was related to mean temperature of the sampling month; (2) Human disturbances significantly affected structure of root-associated fungal community of V. carlesii, and two secondary forest types were similar in root-associated fungal community and were closer to that of the old growth forest; (3) Plant community composition, edaphic parameters, and geographic factors significantly affected root-associated fungal communities of V. carlesii. These results may be helpful in better understanding the maintenance mechanisms of fungal diversity associated with hair roots of ERM plants under human disturbances. PMID:26928608

  10. Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

    Science.gov (United States)

    Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

    2003-01-01

    Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

  11. Inter-annual variability in the thermal structure of an oceanic time series station off Ecuador (1990-2003) associated with El Niño events

    Science.gov (United States)

    Garcés-Vargas, José; Schneider, Wolfgang; Abarca del Río, Rodrigo; Martínez, Rodney; Zambrano, Eduardo

    2005-10-01

    Previously unpublished data (1990-2003) from a marine station located 20 km off the coast of Ecuador (Station La Libertad, 02°12'S, 080°55'W) are employed to investigate oceanic inter-annual variability in the far eastern equatorial Pacific, and its relation to the central-eastern equatorial Pacific. La Libertad is the only time series station between the Galapagos Islands and the South American coast, the region most affected by El Niño events (El Niño 2 region, 0-5°S, 90°W-80°W). Although configured and serviced differently, station La Libertad can be looked at as an eastern extension of the TAO/TRITON monitoring system, whose easternmost mooring is located at 95°W, 1550 km offshore. This study of El Niño's impact on the thermocline and its relationship to sea surface temperature revealed anomalies in the thermocline at station La Libertad some 2-4 months before their appearance at the sea surface. Inter-annual variability, namely quasi-biennial and quasi-quadrennial oscillations, accounts for roughly 80% of the total variance in temperature anomalies observed in the water column at station La Libertad. The coincidence in both phase and amplitude of these inter-annual oscillations explains the strength of El Niño events in the water column off La Libertad. We further show that anomalies in heat content appear 8-9 weeks earlier at 140°W in the equatorial Pacific (6550 km away from the coast) than at the coast itself. The arrival of El Niño, which has important regional social consequences as well as those for local fisheries, could therefore be predicted in the sub-surface waters off Ecuador by using these anomalies as a complementary index. In addition, the speed of the eastward propagation of these El Niño-associated anomalies' suggests the possible participation of higher-order baroclinic mode Kelvin waves and associated interaction processes in the eastern Pacific, which should be further investigated.

  12. Response of Riparian Vegetation in Australia's Largest River Basin to Inter and Intra-Annual Climate Variability and Flooding as Quantified with Landsat and MODIS

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.

    2015-12-01

    Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB), an area that covers over 1M km^2, as a case study. The MDB is the country's primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999-2009). Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the sub- continental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images), Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a 'boom' and 'bust' cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and Okavango River delta in Africa or

  13. Response of Riparian Vegetation in AUSTRALIA"S Largest River Basin to Inter and Intra-Annual Climate Variability and Flooding as Quantified with Landsat and Modis

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.

    2016-06-01

    Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB), an area that covers over 1M km2, as a case study. The MDB is the country's primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999-2009). Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the subcontinental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images), Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a `boom' and `bust' cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and Okavango River delta in Africa or the

  14. The Inter-Annual Variability Analysis of Carbon Exchange in Low Artic Fen Uncovers The Climate Sensitivity And The Uncertainties Around Net Ecosystem Exchange Partitioning

    Science.gov (United States)

    Blanco, E. L.; Lund, M.; Williams, M. D.; Christensen, T. R.; Tamstorf, M. P.

    2015-12-01

    An improvement in our process-based understanding of CO2 exchanges in the Arctic, and their climate sensitivity, is critical for examining the role of tundra ecosystems in changing climates. Arctic organic carbon storage has seen increased attention in recent years due to large potential for carbon releases following thaw. Our knowledge about the exact scale and sensitivity for a phase-change of these C stocks are, however, limited. Minor variations in Gross Primary Production (GPP) and Ecosystem Respiration (Reco) driven by changes in the climate can lead to either C sink or C source states, which likely will impact the overall C cycle of the ecosystem. Eddy covariance data is usually used to partition Net Ecosystem Exchange (NEE) into GPP and Reco achieved by flux separation algorithms. However, different partitioning approaches lead to different estimates. as well as undefined uncertainties. The main objectives of this study are to use model-data fusion approaches to (1) determine the inter-annual variability in C source/sink strength for an Arctic fen, and attribute such variations to GPP vs Reco, (2) investigate the climate sensitivity of these processes and (3) explore the uncertainties in NEE partitioning. The intention is to elaborate on the information gathered in an existing catchment area under an extensive cross-disciplinary ecological monitoring program in low Arctic West Greenland, established under the auspices of the Greenland Ecosystem Monitoring (GEM) program. The use of such a thorough long-term (7 years) dataset applied to the exploration in inter-annual variability of carbon exchange, related driving factors and NEE partition uncertainties provides a novel input into our understanding about land-atmosphere CO2 exchange.

  15. RESPONSE OF RIPARIAN VEGETATION IN AUSTRALIA"S LARGEST RIVER BASIN TO INTER AND INTRA-ANNUAL CLIMATE VARIABILITY AND FLOODING AS QUANTIFIED WITH LANDSAT AND MODIS

    Directory of Open Access Journals (Sweden)

    M. Broich

    2016-06-01

    Full Text Available Australia is a continent subject to high rainfall variability, which has major influences on runoff and vegetation dynamics. However, the resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified in a spatially explicit way. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB, an area that covers over 1M km2, as a case study. The MDB is the country’s primary agricultural area with scarce water resources subject to competing demands and impacted by climate change and more recently by the Millennium Drought (1999–2009. Riparian vegetation in the MDB floodplain suffered extensive decline providing a dramatic degradation of riparian vegetation. We quantified the spatial-temporal impact of rainfall, temperature and flooding patters on vegetation dynamics at the subcontinental to local scales and across inter to intra-annual time scales based on three decades of Landsat (25k images, Bureau of Meteorology data and one decade of MODIS data. Vegetation response varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Vegetation degradation trends were observed over riparian forests and woodlands in areas where flooding regimes have changed to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a ‘boom’ and ‘bust’ cycle, related to inter-annual rainfall variability. Spatial patters of vegetation degradation changed along the N-S rainfall gradient but flooding regimes and vegetation degradation patterns also varied at finer scale, highlighting the importance of a spatially explicit, internally consistent analysis and setting the stage for investigating further cross-scale relationships. Results are of interest for land and water management decisions. The approach developed here can be applied to other areas globally such as the Nile river basin and

  16. CMIP5 land surface models systematically underestimate inter-annual variability of net ecosystem exchange in semi-arid southwestern North America.

    Science.gov (United States)

    MacBean, N.; Scott, R. L.; Biederman, J. A.; Vuichard, N.; Hudson, A.; Barnes, M.; Fox, A. M.; Smith, W. K.; Peylin, P. P.; Maignan, F.; Moore, D. J.

    2017-12-01

    Recent studies based on analysis of atmospheric CO2 inversions, satellite data and terrestrial biosphere model simulations have suggested that semi-arid ecosystems play a dominant role in the interannual variability and long-term trend in the global carbon sink. These studies have largely cited the response of vegetation activity to changing moisture availability as the primary mechanism of variability. However, some land surface models (LSMs) used in these studies have performed poorly in comparison to satellite-based observations of vegetation dynamics in semi-arid regions. Further analysis is therefore needed to ensure semi-arid carbon cycle processes are well represented in global scale LSMs before we can fully establish their contribution to the global carbon cycle. In this study, we evaluated annual net ecosystem exchange (NEE) simulated by CMIP5 land surface models using observations from 20 Ameriflux sites across semi-arid southwestern North America. We found that CMIP5 models systematically underestimate the magnitude and sign of NEE inter-annual variability; therefore, the true role of semi-arid regions in the global carbon cycle may be even more important than previously thought. To diagnose the factors responsible for this bias, we used the ORCHIDEE LSM to test different climate forcing data, prescribed vegetation fractions and model structures. Climate and prescribed vegetation do contribute to uncertainty in annual NEE simulations, but the bias is primarily caused by incorrect timing and magnitude of peak gross carbon fluxes. Modifications to the hydrology scheme improved simulations of soil moisture in comparison to data. This in turn improved the seasonal cycle of carbon uptake due to a more realistic limitation on photosynthesis during water stress. However, the peak fluxes are still too low, and phenology is poorly represented for desert shrubs and grasses. We provide suggestions on model developments needed to tackle these issues in the future.

  17. The role of storage capacity in coping with intra- and inter-annual water variability in large river basins

    Science.gov (United States)

    Gaupp, Franziska; Hall, Jim; Dadson, Simon

    2015-12-01

    Societies and economies are challenged by variable water supplies. Water storage infrastructure, on a range of scales, can help to mitigate hydrological variability. This study uses a water balance model to investigate how storage capacity can improve water security in the world’s 403 most important river basins, by substituting water from wet months to dry months. We construct a new water balance model for 676 ‘basin-country units’ (BCUs), which simulates runoff, water use (from surface and groundwater), evaporation and trans-boundary discharges. When hydrological variability and net withdrawals are taken into account, along with existing storage capacity, we find risks of water shortages in the Indian subcontinent, Northern China, Spain, the West of the US, Australia and several basins in Africa. Dividing basins into BCUs enabled assessment of upstream dependency in transboundary rivers. Including Environmental Water Requirements into the model, we find that in many basins in India, Northern China, South Africa, the US West Coast, the East of Brazil, Spain and in the Murray basin in Australia human water demand leads to over-abstraction of water resources important to the ecosystem. Then, a Sequent Peak Analysis is conducted to estimate how much storage would be needed to satisfy human water demand whilst not jeopardizing environmental flows. The results are consistent with the water balance model in that basins in India, Northern China, Western Australia, Spain, the US West Coast and several basins in Africa would need more storage to mitigate water supply variability and to meet water demand.

  18. The twentieth century Africal easterly waves in reanalysis systems and IPCC simulations, from intra-seasonal to inter-annual variability

    Energy Technology Data Exchange (ETDEWEB)

    Ruti, Paolo; Dell' Aquila, Alessandro [ENEA, CR Casaccia, UTMEA-CLIM, Rome (Italy)

    2010-11-15

    The nature of intraseasonal and interannual variability of African easterly waves (AEWs) in IPCC-CMIP3 global simulations is investigated in comparison with 40-year NCEP and ERA40 products. AEWs are a major source of atmospheric variability over the Sahel and particularly over West Africa. An accurate representation of AEWs dynamics is therefore an important precondition to skilled climate predictions and seasonal forecasts for this area. We describe the synoptic features of these disturbances and we illustrate a statistical link, at interannual timescale, between Sea Surface Temperature and AEWs activity. At intraseasonal time scale, the models exhibit a wide variety of behaviours in reproducing the synoptic features of the disturbances, namely AEWs amplitude and pattern. It is possible to classify the models into two groups, one localizing intense variability well inside the continental area, and the other exhibiting a weaker variance mostly placed over West Africa. Concerning the inter-annual variability, we point out a statistical link between SST anomalies and AEWs activity that reveals a strong influence of the ENSO events on the variability of the disturbances over the Guinean coasts. Warm/cold ENSO events occur in conjunction with suppressed/enhanced AEWs through upper tropospheric teleconnection bridge. Only two model running at significantly different vertical and horizontal resolution (INM and INGV-SGX) are able to reproduce this mechanism in accordance to what observed in the global reanalysis systems. Our result introduces non-negligible caveats with respect to the ability of most of CMIP3 models in obtaining reliable description of AEWs. (orig.)

  19. A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink

    DEFF Research Database (Denmark)

    Landschützer, P.; Gruber, N.; Bakker, D.C.E.

    2013-01-01

    –18° N, 0.11 ± 0.07 Pg C yr–1), and uptake in the subtropical/temperate South Atlantic south of 18° S (–0.16 ± 0.06 Pg C yr–1), consistent with recent studies. We find the strongest seasonal variability of the CO2 flux in the temperature driven subtropical North Atlantic, with uptake in winter......The Atlantic Ocean is one of the most important sinks for atmospheric carbon dioxide (CO2), but this sink is known to vary substantially in time. Here we use surface ocean CO2 observations to estimate this sink and the temporal variability from 1998 to 2007 in the Atlantic Ocean. We benefit from (i...

  20. Inter-annual variability of the Pelagic-Benthic coupling in the upwelling system off central Chile

    Directory of Open Access Journals (Sweden)

    M. Graco

    2006-01-01

    Full Text Available The coastal region of central Chile (36° S is one of the most productive coastal systems, characterized by a marked seasonality in the upwelling regime, that brings subsurface waters rich in nutrient and poor in oxygen (ESSW into the euphotic zone. This oceanographic condition depends basically on the equatorward wind strength and is modified on different time scales, with the El Niño-Southern Oscillation (ENSO phenomenon as the main source of interannual variability in the Pacific Ocean. Here we present an effort to integrate physical and biogeochemical variability associated with in situ information and experiments at coastal stations off central Chile (36° S in order to improve the knowledge on the pelagic-benthic coupling in this upwelling system during the warm ENSO phase or El Niño. Carbon fluxes exported from the water column to the sediments and the ammonium exchange across the sediment-water interface are discussed together with oceanographic and benthic conditions. All measurements and estimations were carried out from May 1997 until April 2001 at two stations, one located inside Concepción Bay (~28 m depth, and the other on the continental shelf at ~36° S (~88 m depth. The results show that the pelagic and benthic systems are strongly coupled off central Chile (36° S. Oceanographic variability associated with upwelling events (seasonal scale and an El Niño event (interannual scale was observed. The carbon fluxes exported to the sediments, the benthic conditions (i.e., quantity and quality of the sediment organic matter, and the ammonium exchange across the sediment-water interface, responded to the seasonal regime of upwelling during non El Niño years as well as to the ENSO related oceanographic variability.

  1. Inter- and intra-annual variability of fluvial sediment transport in the proglacial river Riffler Bach (Weißseeferner, Ötztal Alps, Tyrol)

    Science.gov (United States)

    Baewert, Henning; Weber, Martin; Morche, David

    2015-04-01

    The hydrology of a proglacial river is strongly affected by glacier melting. Due to glacier retreat the effects of snow melt and rain storms will become more important in future decades. Additionally, the development of periglacial landscapes will play a more important role in the hydrology of proglacial rivers. The importance of paraglacial sediment sources in sediment budgets of glacier forefields is increasing, while the role of glacial erosion is declining. In two consecutive ablation seasons the fluvial sediment transport of the river Riffler Bach in the Kaunertal (Tyrol/Austria) was quantified. The catchment area of this station is 20 km² with an altitudinal range from 1929 m to 3518 m above msl. The "Weißseeferner" glacier (2.34 km² in 2012) is the greatest of the remaining glaciers. An automatic water sampler (AWS 2002) and a probe for water level were installed were installed at the outlet of the catchment. In order to calculate annual stage-discharge-relations, discharge (Q) was repeatedly measured with current meters. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load (BL) samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In 2012, 154 water samples were sampled during 7 periods and subsequently filtered to quantify suspended sediment concentrations (SSC). A Q-SSC-relation was calculated for every period due to the high variability in suspended sediment transport. In addition, the grain size distribution of the filtered material was determined by laser diffraction analysis. In 2013, the same procedure was performed for 232 water samples which were collected during 9 periods. Meteorological data were logged at the climate station "Weißsee", which is located in the centre of the study area. First results show a high variability of discharge and solid sediment transport both at the inter-annual as well as at the intra-annual

  2. Wind-generated Electricity in China: Decreasing Potential, Inter-annual Variability and Association with Changing Climate.

    Science.gov (United States)

    Sherman, Peter; Chen, Xinyu; McElroy, Michael B

    2017-11-24

    China hosts the world's largest market for wind-generated electricity. The financial return and carbon reduction benefits from wind power are sensitive to changing wind resources. Wind data derived from an assimilated meteorological database are used here to estimate what the wind generated electricity in China would have been on an hourly basis over the period 1979 to 2015 at a geographical resolution of approximately 50 km × 50 km. The analysis indicates a secular decrease in generating potential over this interval, with the largest declines observed for western Inner Mongolia (15 ± 7%) and the northern part of Gansu (17 ± 8%), two leading wind investment areas. The decrease is associated with long-term warming in the vicinity of the Siberian High (SH), correlated also with the observed secular increase in global average surface temperatures. The long-term trend is modulated by variability relating to the Pacific Decadal Oscillation (PDO) and the Arctic Oscillation (AO). A linear regression model incorporating indices for the PDO and AO, as well as the declining trend, can account for the interannual variability of wind power, suggesting that advances in long-term forecasting could be exploited to markedly improve management of future energy systems.

  3. Combined role of heat and water stresses on wheat, maize and rice inter-annual variability and trend from 1980 to 2010.

    Science.gov (United States)

    Zampieri, M.; Ceglar, A., , Dr; Dentener, F., , Dr; van den Berg, M., , Dr; Toreti, A., , Dr

    2017-12-01

    Heat waves and drought are often considered the most damaging climatic stressors for wheat and maize. In this study, based on data derived from observations, we characterize and attribute the effects of these climate extremes on wheat and maize yield anomalies (at global and national scales) with respect to the mean trend from 1980 to 2010. Using a combination of up-to-date heat wave and drought indexes (i.e. the Heat Magnitude Day, HMD, and the Standardized Precipitation Evapotranspiration Index, SPEI), we have developed a composite indicator (i.e. the Combined Stress Index, CSI) that is able to capture the spatio-temporal characteristics of the underlying physical processes in the different agro-climatic regions of the world. At the global level, our diagnostic explains the 42% and the 50% of the inter-annual wheat and maize production variabilities, respectively. The relative importance of heat stress and drought in determining the yield anomalies depends on the region. Compared to maize, and in contrast to common perception, water excess affects wheat production more than drought in several countries. The index definition can be modified in order to quantify the role of combined heat and water stress events occurrence in determining the recorded yield trends as well. Climate change is increasingly limiting maize yields in several countries, especially in Europe and China. A comparable opposite signal, albeit less statistically significant, is found for the USA, which is the main world producer. As for rice, we provide a statistical evidence pointing out to the importance of considering the interactions with the horizontal surface waters fluxes carried out by the rivers. In fact, compared to wheat and maize, the CSI statistical skills in explaining rice production variability are quite reduced. This issue is particularly relevant in paddy fields and flooded lowlands where rice is mainly grown. Therefore, we have modified the procedure including a proxy for the

  4. North Atlantic atmospheric and ocean inter-annual variability over the past fifty years - Dominant patterns and decadal shifts

    Science.gov (United States)

    Hauser, Tristan; Demirov, Entcho; Zhu, Jieshun; Yashayaev, Igor

    2015-03-01

    The atmosphere and ocean of the North Atlantic have undergone significant changes in the past century. To understand these changes, their mechanisms, and their regional implications requires a quantitative understanding of processes in the coupled ocean and atmosphere system. Central to this understanding is the role played by the dominant patterns of ocean and atmospheric variability which define coherent variations in physical characteristics over large areas. Cluster analysis is used in this article to identify the patterns of the North Atlantic atmospheric variability in the subseasonal and interannual spectral intervals. Four dominant subseasonal weather regimes are defined using Bayesian Gaussian mixture models. All correlation patterns of the Sea Level Pressure (SLP) anomalies with the membership probability time series for the weather regimes show similarities with the dipole structure typical for the North Atlantic Oscillation (NAO). The SLP patterns of two of the regimes represent the opposite phases NAO+ and NAO-. The two other weather regimes, the Atlantic Ridge (AR) and Scandinavian-Greenland dipole (SG), have dipole spatial structures with the northern and southern centers of action shifted with respect to the NAO pattern. These two patterns define blocking structures over Scandinavia and near the southern tip of Greenland, respectively. The storm tracks typical for the four regimes resemble the well known paths for positive/negative phases of NAO for the NAO+/NAO- weather regimes, and paths influenced by blocking off the south Greenland tip for AR and over Scandinavia for SG. The correlation patterns of momentum and heat fluxes to the ocean for the four regimes have tripole structures with positive (warm) downward heat flux anomalies over the Subpolar North Atlantic (SPNA) for the NAO- and the AR and negative heat flux anomalies over the SPNA for the NAO+. The downward heat flux anomalies associated with the SG are negative over the Labrador Sea and

  5. Inter-annual variability and potential for selectivity in the diets of deep-water Antarctic echinoderms

    Science.gov (United States)

    Wigham, B. D.; Galley, E. A.; Smith, C. R.; Tyler, P. A.

    2008-11-01

    The continental shelf of the West Antarctic Peninsula (WAP) is a highly productive region but also unusually deep as a result of isostatic depression by the polar ice cap. The close coupling of surface processes with those of the benthos would be expected in such a seasonally variable environment; however, the cold, deep conditions of the WAP shelf may allow for the persistence of organic material in the sediments as a "food bank". Chlorophyll and carotenoid pigments were determined from the gut contents of seven species of echinoderm and from the surficial sediment on the bathyal continental shelf. Samples were collected as part of the FOODBANCS programme during successive cruises in austral spring (October 2000) and austral autumn (March 2001). Pigments were identified and quantified using reverse-phase high-performance liquid chromatography (HPLC). A lack of qualitative selectivity was observed among species, compared to that observed for deep-water assemblages at temperate latitudes, supporting the theory of a persistent "food bank". However, significant quantitative differences were observed among species and between years and sampling location on the shelf. Species differences were marked between those we classified as "true" deposit feeders and those species whose diet also may be supplemented by scavenging and/or grazing.

  6. Inter-annual climate variability and zooplankton: applying teleconnection indices to two deep subalpine lakes in Italy

    Directory of Open Access Journals (Sweden)

    Marina Manca

    2014-08-01

    Full Text Available Investigating relation between meteo-climatic indices and between-year variation in Daphnia population density and phenology is crucial for e.g. predicting impact of climate change on lake ecosystem structure and functioning. We tested whether and how two teleconnection indices calculated for the winter period, namely the East Atlantic pattern (EADJF and the Eastern Mediterranean Pattern (EMPDJF were correlated with Daphnia population growth in two Italian subalpine lakes, Garda and Maggiore. We investigated between-lake temporal coherence in: i water temperature within the water layer in which Daphnia is distributed; ii timing of Daphnia initial and spring maximum population density peak and iii the level of Daphnia spring maximum population density peak over an eleven-year period (1998-2008 of unchanged predation pressure by fish and invertebrates, and of common oligotrophy. Between-lake temporal coherence was high for an earlier start, an earlier, and lower, Daphnia population spring density peak after milder winters. Peak density level was coherently, positively correlated with soluble reactive phosphorus (SRP concentration. We hypothesized that Daphnia peak densities were related to atmospheric modes of variability in winter and to the degree of late winter mixing promoting replenishment of algal nutrients into upper water layers and phytoplankton growth, enhancing food availability and Daphnia fecundity, promoting Daphnia peak. 

  7. Inter-Annual Variability of Area-Scaled Gaseous Carbon Emissions from Wetland Soils in the Liaohe Delta, China.

    Science.gov (United States)

    Ye, Siyuan; Krauss, Ken W; Brix, Hans; Wei, Mengjie; Olsson, Linda; Yu, Xueyang; Ma, Xueying; Wang, Jin; Yuan, Hongming; Zhao, Guangming; Ding, Xigui; Moss, Rebecca F

    2016-01-01

    Global management of wetlands to suppress greenhouse gas (GHG) emissions, facilitate carbon (C) sequestration, and reduce atmospheric CO2 concentrations while simultaneously promoting agricultural gains is paramount. However, studies that relate variability in CO2 and CH4 emissions at large spatial scales are limited. We investigated three-year emissions of soil CO2 and CH4 from the primary wetland types of the Liaohe Delta, China, by focusing on a total wetland area of 3287 km2. One percent is Suaeda salsa, 24% is Phragmites australis, and 75% is rice. While S. salsa wetlands are under somewhat natural tidal influence, P. australis and rice are managed hydrologically for paper and food, respectively. Total C emissions from CO2 and CH4 from these wetland soils were 2.9 Tg C/year, ranging from 2.5 to 3.3 Tg C/year depending on the year assessed. Primary emissions were from CO2 (~98%). Photosynthetic uptake of CO2 would mitigate most of the soil CO2 emissions, but CH4 emissions would persist. Overall, CH4 fluxes were high when soil temperatures were >18°C and pore water salinity emissions from rice habitat alone in the Liaohe Delta represent 0.2% of CH4 carbon emissions globally from rice. With such a large area and interannual sensitivity in soil GHG fluxes, management practices in the Delta and similar wetlands around the world have the potential not only to influence local C budgeting, but also to influence global biogeochemical cycling.

  8. Inter-annual variability in flowering of orchids: lessons learned from 8 years of monitoring in a Mediterranean region of France

    Directory of Open Access Journals (Sweden)

    Hélène Vogt-Schilb

    2013-12-01

    Full Text Available It is important to evaluate the loss of biodiversity caused by global changes. In the case of orchids, it is still unclear how long the monitoring duration should be chosen in order to achieve a good compromise between the reliability of the orchid dynamics recorded and sampling duration (e.g. years of monitoring. This study aims to propose a method of monitoring orchids. Using a large database, we investigated the inter-annual variability in flowering of orchids in a French Mediterranean region. The database includes an 8-year-long study (2006–2013 of 47 species at 26 locations in three different types of habitats. The number of individual plants that flowered per species varied significantly between years, but not the number of species. Depending on habitat, two to four years were needed to observe the total number of species per location. Therefore, in Mediterranean regions a one-year-study seems to be insufficient to produce reliable results.

  9. From egg production to recruits: Connectivity and inter-annual variability in the recruitment patterns of European anchovy in the northwestern Mediterranean

    Science.gov (United States)

    Ospina-Alvarez, Andres; Catalán, Ignacio A.; Bernal, Miguel; Roos, David; Palomera, Isabel

    2015-11-01

    We show the application of a Spatially-Explicit Individual-Based Model (SEIBM) to understand the recruitment process of European anchovy. The SEIBM is applied to simulate the effects of inter-annual variability in parental population spawning behavior and intensity, and ocean dynamics, on the dispersal of eggs and larvae from the spawning area in the Gulf of Lions (GoL) towards the coastal nursery areas in the GoL and Catalan Sea (northwestern Mediterranean Sea). For each of seven years (2003-2009), we initialize the SEIBM with the real positions of anchovy eggs during the spawning peak, from an acoustics-derived eggs production model. We analyze the effect of spawners' distribution, timing of spawning, and oceanographic conditions on the connectivity patterns, growth, dispersal distance and late-larval recruitment (14 mm larva recruits, R14) patterns. The area of influence of the Rhône river plume was identified as having a high probability of larval recruitment success (64%), but up to 36% of R14 larvae end up in the Catalan Coast. We demonstrate that the spatial paths of larvae differ dramatically from year to year, and suggest potential offshore nursery grounds. We showed that our simulations are coherent with existing recruitment proxies and therefore open new possibilities for fisheries management.

  10. Universal Inverse Power-Law Distribution for Fractal Fluctuations in Dynamical Systems: Applications for Predictability of Inter-Annual Variability of Indian and USA Region Rainfall

    Science.gov (United States)

    Selvam, A. M.

    2017-01-01

    Dynamical systems in nature exhibit self-similar fractal space-time fluctuations on all scales indicating long-range correlations and, therefore, the statistical normal distribution with implicit assumption of independence, fixed mean and standard deviation cannot be used for description and quantification of fractal data sets. The author has developed a general systems theory based on classical statistical physics for fractal fluctuations which predicts the following. (1) The fractal fluctuations signify an underlying eddy continuum, the larger eddies being the integrated mean of enclosed smaller-scale fluctuations. (2) The probability distribution of eddy amplitudes and the variance (square of eddy amplitude) spectrum of fractal fluctuations follow the universal Boltzmann inverse power law expressed as a function of the golden mean. (3) Fractal fluctuations are signatures of quantum-like chaos since the additive amplitudes of eddies when squared represent probability densities analogous to the sub-atomic dynamics of quantum systems such as the photon or electron. (4) The model predicted distribution is very close to statistical normal distribution for moderate events within two standard deviations from the mean but exhibits a fat long tail that are associated with hazardous extreme events. Continuous periodogram power spectral analyses of available GHCN annual total rainfall time series for the period 1900-2008 for Indian and USA stations show that the power spectra and the corresponding probability distributions follow model predicted universal inverse power law form signifying an eddy continuum structure underlying the observed inter-annual variability of rainfall. On a global scale, man-made greenhouse gas related atmospheric warming would result in intensification of natural climate variability, seen immediately in high frequency fluctuations such as QBO and ENSO and even shorter timescales. Model concepts and results of analyses are discussed with reference

  11. Secular change and inter-annual variability of the Gulf Stream position, 1993-2013, 70°-55°W

    Science.gov (United States)

    Bisagni, James J.; Gangopadhyay, Avijit; Sanchez-Franks, Alejandra

    2017-07-01

    The Gulf Stream (GS) is the northeastward-flowing surface limb of the Atlantic Ocean's meridional overturning circulation (AMOC) ;conveyer belt; that flows towards Europe and the Nordic Seas. Changes in the GS position after its separation from the coast at Cape Hatteras, i.e., from 75°W to 50°W, may be key to understanding the AMOC, sea level variability and ecosystem behavior along the east coast of North America. In this study we compare secular change and inter-annual variability (IAV) of the Gulf Stream North Wall (GSNW) position with equator-ward Labrador Current (LC) transport along the southwestern Grand Banks near 52°W using 21 years (1993-2013) of satellite altimeter data. Results at 55°, 60°, and 65°W show a significant southward (negative) secular trend for the GSNW, decreasing to a small but insignificant southward trend at 70°W. IAV of de-trended GSNW position residuals also decreases to the west. The long-term secular trend of annual mean upper layer (200 m) LC transport near 52°W is positive. Furthermore, IAV of LC transport residuals near 52°W along the southwestern Grand Banks are significantly correlated with GSNW position residuals at 55°W at a lag of +1-year, with positive (negative) LC transport residuals corresponding to southward (northward) GSNW positions one year later. The Taylor-Stephens index (TSI) computed from the first principal component of the GSNW position from 79° to 65°W shows a similar relationship with a more distal LC index computed along altimeter ground track 250 located north of the Grand Banks across Hamilton Bank in the western Labrador Sea. Increased (decreased) sea height differences along ground track 250 are significantly correlated with a more southward (northward) TSI two years later (lag of +2-years). Spectral analysis of IAV reveals corresponding spectral peaks at 5-7 years and 2-3 years for the North Atlantic Oscillation (NAO), GSNW (70°-55°W) and LC transport near 52°W for the 1993-2013 period

  12. Inter-annual variability of surface ozone at coastal (Dumont d'Urville, 2004–2014 and inland (Concordia, 2007–2014 sites in East Antarctica

    Directory of Open Access Journals (Sweden)

    M. Legrand

    2016-07-01

    Full Text Available Surface ozone has been measured since 2004 at the coastal East Antarctic site of Dumont d'Urville (DDU, and since 2007 at the Concordia station located on the high East Antarctic plateau. This paper discusses long-term changes, seasonal and diurnal cycles, as well as inter-annual summer variability observed at these two East Antarctic sites. At Concordia, near-surface ozone data were complemented by balloon soundings and compared to similar measurements done at the South Pole. The DDU record is compared to those obtained at the coastal site of Syowa, also located in East Antarctica, as well as the coastal sites of Neumayer and Halley, both located on the coast of the Weddell Sea in West Antarctica. Surface ozone mixing ratios exhibit very similar seasonal cycles at Concordia and the South Pole. However, in summer the diurnal cycle of ozone is different at the two sites with a drop of ozone in the afternoon at Concordia but not at the South Pole. The vertical distribution of ozone above the snow surface also differs. When present, the ozone-rich layer located near the ground is better mixed and deeper at Concordia (up to 400 m than at the South Pole during sunlight hours. These differences are related to different solar radiation and wind regimes encountered at these two inland sites. DDU appears to be the coastal site where the impact of the late winter/spring bromine chemistry is the weakest, but where the impact of elevated ozone levels caused by NOx snow emissions from the high Antarctic plateau is the highest. The highest impact of the bromine chemistry is seen at Halley and Neumayer, and to a lesser extent at Syowa. These three sites are only weakly impacted by the NOx chemistry and the net ozone production occurring on the high Antarctic plateau. The differences in late winter/spring are attributed to the abundance of sea ice offshore from the sites, whereas those in summer are related to the topography of East Antarctica that promotes

  13. Seasonal and inter-annual variability in velocity and frontal position of Siachen Glacier (Eastern Karakorum) using multi-satellite data

    Science.gov (United States)

    Usman, M.; Furuya, M.; Sakakibara, D.; Abe, T.

    2017-12-01

    The anomalous behavior of Karakorum glaciers is a hot topic of discussion in the scientific community. Siachen Glacier is one of the longest glaciers ( 75km) in Karakorum Range. This glacier is supposed to be a surge type but so far no studies have confirmed this claim. Detailed velocity mapping of this glacier can possibly provide some clues about intra/inter-annual changes in velocity and observed terminus. Using L-band SAR data of ALOS-1/2, we applied the feature tracking technique (search patch of 128x128 pixels (range x azimuth) , sampling interval of 12x36 pixels) to derive velocity changes; we used GAMMA software. The velocity was calculated by following the parallel flow assumption. To calculate the local topographic gradient unit vector, we used ASTER-GDEM. We also used optical images acquired by Landsat 5 Thematic Mapper (TM), the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) to derive surface velocity. The algorithm we used is Cross-Correlation in Frequency domain on Orientation images (CCF-O). The velocity was finally calculated by setting a flow line and averaging over the area of 200x200m2. The results indicate seasonal speed up signals that modulate inter-annually from 1999 to 2011, with slight or no change in the observed frontal position. However, in ALOS-2 data, the `observed terminus' seems to have been advancing.

  14. Inter-annual Variability of Evapotranspiration in a Semi-arid Oak-savanna Ecosystem: Measured and Modeled Buffering to Precipitation Changes

    Science.gov (United States)

    Raz-Yaseef, N.; Sonnentag, O.; Kobayashi, H.; Baldocchi, D. D.

    2010-12-01

    Precipitation (P) is the primary control on vegetation dynamics and productivity, implying that climate induced disturbances in frequency and timing of P are intimately coupled with fluxes of carbon, water and energy. Future climate change is expected to increase extreme rainfall events as well as droughts, suggesting linked vegetation changes to an unknown extent. Semi-arid climates experience large inter-annual variability (IAV) in P, creating natural conditions adequate to study how year-to-year changes in P affect atmosphere-biosphere fluxes. We used a 10-year flux database collected at a semi-arid savanna site in order to: (1) define IAV in P by means of frequency and timing; (2) investigate how changes in P affect the ecohydrology of the forest and its partitioning into the main vapor fluxes, and (3) evaluate model capability to predict IAV of carbon and water fluxes above and below the canopy. This is based on the perception that the capability of process-oriented models to construct the deviation, and not the average, is important in order to correctly predict ecosystem sensitivity to climate change. Our research site was a low density and low LAI (0.8) semi-arid (P=523±180 mm yr-1) savanna site, combined of oaks and grass, and located at Tonzi ranch, California. Measurements of carbon and water fluxes above and below the tree canopy using eddy covariance and supplementary measurements have been made since 2001. Measured fluxes were compared to modeled based on two bio-meteorological process-oriented ecosystem models: BEPS and 3D-CAONAK. Our results show that IAV in P was large, and standard deviation (STD) was 38% of the average. Accordingly, the wet soil period (measured volumetric water content > 8%) varied between 156 days in dry years to 301 days in wet years. IAV of the vapor fluxes were lower than that of P (STD was 17% for the trees and 23% for the floor components), suggesting on ecosystem buffering to changes in P. The timing of grass green up

  15. Inter-annual variability of NDVI in response to long-term warming and fertilization in wet sedge and tussock tundra.

    Science.gov (United States)

    Boelman, Natalie T; Stieglitz, Marc; Griffin, Kevin L; Shaver, Gaius R

    2005-05-01

    This study explores the relationship between the normalized difference vegetation index (NDVI) and aboveground plant biomass for tussock tundra vegetation and compares it to a previously established NDVI-biomass relationship for wet sedge tundra vegetation. In addition, we explore inter-annual variation in NDVI in both these contrasting vegetation communities. All measurements were taken across long-term experimental treatments in wet sedge and tussock tundra communities at the Toolik Lake Long Term Ecological Research (LTER) site, in northern Alaska. Over 15 years (for wet sedge tundra) and 14 years (for tussock tundra), N and P were applied in factorial experiments (N, P and N+P), air temperature was increased using greenhouses with and without N+P fertilizer, and light intensity was reduced by 50% using shade cloth. during the peak growing seasons of 2001, 2002, and 2003, NDVI measurements were made in both the wet sedge and tussock tundra experimental treatment plots, creating a 3-year time series of inter-annual variation in NDVI. We found that: (1) across all tussock experimental tundra treatments, NDVI is correlated with aboveground plant biomass (r2 = 0.59); (2) NDVI-biomass relationships for tussock and wet sedge tundra communities are community specific, and; (3) NDVI values for tussock tundra communities are typically, but not always, greater than for wet sedge tundra communities across all experimental treatments. We suggest that differences between the response of wet sedge and tussock tundra communities in the same experimental treatments result from the contrasting degree of heterogeneity in species and functional types that characterize each of these Arctic tundra vegetation communities.

  16. Inter-annual variability of air mass and acidified pollutants transboundary exchange in the north-eastern part of the EANET region

    Science.gov (United States)

    Gromov, Sergey A.; Trifonova-Yakovleva, Alisa; Gromov, Sergey S.

    2016-04-01

    ]. This dataset provides comprehensive monthly statistics on the wind meteorological regime at the stations of interest in a given range of altitudes. Based on long-term source observational data, the dataset is assumed being representative up to date, which allowed us to estimate monthly pollutant fluxes for the years 2006-2008 over segments of the Russian border and its whole [4]. In the current phase of our study, we calculate the inter-annual variations in the transboundary pollutant fluxes for 2000-2012 using longer-term EANET data and transient changes in air mass fluxes derived from the meteorological wind fields from ERA INTERIM re-analysis [5]. We gauge similar average air transport terms and dynamics from the statistical and reanalysis data, which bolsters our earlier findings. The reanalysis data, being naturally more variable, convolutes the variations in net air fluxes and pollutant concentrations into several episodes we emphasise, in addition to the integral pollutant transfer terms we estimate. At last, we discuss on the possibility of climate change effect on the flux strength and dynamics together with regional air quality tendencies in North-East Asia countries. References: Izrael, Yu.A., et al.: Monitoring of the Transboundary Air Pollution Transport. Gidrometeoizdat, Leningrad, 303 p., 187 (in Russian). Akimoto H., et al.: Periodic Report of the State of Acid Deposition in East Asia. Part I: Regional Assessment. EANET-UNEP/RRC.AP-ADORC, 258 p., 2006. Brukhan, F.F.: Aeroclimatic Characteristics of the Mean Winds over USSR (ed. Ignatjushina E.N.). Gidrometeoizdat, Moscow, 54 p., 1984 (in Russian). Gromov S.A., et al.: First-order evaluation of transboundary pollution fluxes in areas of EANET stations in Eastern Siberia and the Russian Far East. EANET Science Bulletin, vol. 3, pp. 195-203, 2013. Dee, D. P., et al.: The ERA-Interim reanalysis: configuration and performance of the data assimilation system, Quart. J. Royal Met. Soc., 137, 553-597, doi: 10

  17. Continuous 25-yr aerosol records at coastal Antarctica - I: inter-annual variability of ionic compounds and links to climate indices

    Energy Technology Data Exchange (ETDEWEB)

    Weller, Rolf; Koenig-Langlo, Gert (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)), e-mail: Rolf.Weller@awi.de; Wagenbach, Dietmar; Elsaesser, Christoph (Institut fur Umweltphysik, Univ. of Heidelberg, Heidelberg (Germany)); Legrand, Michel (Laboratoire de Glaciologie et Geophysique de l' Environnement du Centre National de la Recherche Scientifique, St Martin d' Heres (France)); Tian-Kunze, Xiangshan (Institut fur Meereskunde, Univ. of Hamburg, Hamburg (Germany))

    2011-11-15

    The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non-sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (-3.6 +- 2.5% per year between 1983 and 1993 and +4.0 +- 3.2% per year from 1993-2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses revealed that relations to sea ice extent and various circulation indices are weak at best or not significant. In particular, no consistent link between sea ice extent and sea salt loadings was evident suggesting only a rather local relevance of the NM sea salt record. Nevertheless, a higher Southern Annular Mode index tended to entail a lower biogenic sulphur signal. In examining the spatial uniformity of the NM findings we contrasted them to respective 17 yr records from the coastal Dumont d'Urville Station. We found similar long-term trends for nitrate, indicating an Antarctic-wide but not identifiable atmospheric signal, although any significant impact of solar activity or pollution could be ruled out. No inter-site variability on the multiannual scale was evident for the other ionic compounds

  18. Inter-annual variability in apparent relative production, survival, and growth of juvenile Lost River and shortnose suckers in Upper Klamath Lake, Oregon, 2001–15

    Science.gov (United States)

    Burdick, Summer M.; Martin, Barbara A.

    2017-06-15

    Executive SummaryPopulations of the once abundant Lost River (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) of the Upper Klamath Basin, decreased so substantially throughout the 20th century that they were listed under the Endangered Species Act in 1988. Major landscape alterations, deterioration of water quality, and competition with and predation by exotic species are listed as primary causes of the decreases in populations. Upper Klamath Lake populations are decreasing because fish lost due to adult mortality, which is relatively low for adult Lost River suckers and variable for adult shortnose suckers, are not replaced by new young adult suckers recruiting into known adult spawning aggregations. Catch-at-age and size data indicate that most adult suckers presently in Upper Klamath Lake spawning populations were hatched around 1991. While, a lack of egg production and emigration of young fish (especially larvae) may contribute, catch-at-length and age data indicate high mortality during the first summer or winter of life may be the primary limitation to the recruitment of young adults. The causes of juvenile sucker mortality are unknown.We compiled and analyzed catch, length, age, and species data on juvenile suckers from Upper Klamath Lake from eight prior studies conducted from 2001 to 2015 to examine annual variation in apparent production, survival, and growth of young suckers. We used a combination of qualitative assessments, general linear models, and linear regression to make inferences about annual differences in juvenile sucker dynamics. The intent of this exercise is to provide information that can be compared to annual variability in environmental conditions with the hopes of understanding what drives juvenile sucker population dynamics.Age-0 Lost River suckers generally grew faster than age-0 shortnose suckers, but the difference in growth rates between the two species varied among years. This unsynchronized annual variation in

  19. Origins of streamflow in a crystalline basement catchment in a sub-humid Sudanian zone: The Donga basin (Benin, West Africa): Inter-annual variability of water budget

    Science.gov (United States)

    Séguis, L.; Kamagaté, B.; Favreau, G.; Descloitres, M.; Seidel, J.-L.; Galle, S.; Peugeot, C.; Gosset, M.; Le Barbé, L.; Malinur, F.; Van Exter, S.; Arjounin, M.; Boubkraoui, S.; Wubda, M.

    2011-05-01

    SummaryDuring the last quarter of the 20th century, West Africa underwent a particularly intense and generalized drought. During this period, the biggest drops in streamflow were observed in the Sudanian zone rather than in the Sahelian zone, but the reasons are still poorly understood. In 2000, a meso-scale hydrological observatory was set up in the sub-humid Sudanian zone of the Upper Ouémé Valley (Benin). Three embedded catchments of 12-586 km 2 located on a crystalline bedrock were intensively instrumented to document the different terms of the water budget and to identify the main streamflow generating processes and base-flow mechanisms at different scales. Geophysical, hydrological and geochemical data were collected throughout the catchments from 2002 to 2006. Crossing these data helped define their hydrological functioning. The region has seasonal streamflow, and the permanent groundwater in the weathered mantle does not drain to rivers, instead, seasonal perched groundwaters are the major contributor to annual streamflow. The perched groundwaters are mainly located in seasonally waterlogged sandy layers in the headwater bottom-lands called bas-fonds in French-speaking West Africa of 1st order streams. During the period 2003-2006, regolith groundwater recharge ranged between 10% and 15% of the annual rainfall depth. Depletion of permanent groundwater during the dry season is probably explained by local evapotranspiration which was seen not to be limited to gallery forests. During the 4-year study period, a reduction of 20% in annual rainfall led to a 50% reduction in streamflow. This reduction was observed in the two components of the flow: direct runoff and drainage of perched groundwater. Thanks to the comprehensive dataset obtained, the results obtained for the Donga experimental catchment are now being extrapolated to the whole upper Ouémé valley, which can be considered as representative of sub-humid Sudanian rivers flowing on a crystalline

  20. Investigating the Relationship between the Inter-Annual Variability of Satellite-Derived Vegetation Phenology and a Proxy of Biomass Production in the Sahel

    Directory of Open Access Journals (Sweden)

    Michele Meroni

    2014-06-01

    Full Text Available In the Sahel region, moderate to coarse spatial resolution remote sensing time series are used in early warning monitoring systems with the aim of detecting unfavorable crop and pasture conditions and informing stakeholders about impending food security risks. Despite growing evidence that vegetation productivity is directly related to phenology, most approaches to estimate such risks do not explicitly take into account the actual timing of vegetation growth and development. The date of the start of the season (SOS or of the peak canopy density can be assessed by remote sensing techniques in a timely manner during the growing season. However, there is limited knowledge about the relationship between vegetation biomass production and these variables at the regional scale. This study describes the first attempt to increase our understanding of such a relationship through the analysis of phenological variables retrieved from SPOT-VEGETATION time series of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR. Two key phenological variables (growing season length (GSL; timing of SOS and the maximum value of FAPAR attained during the growing season (Peak are analyzed as potentially related to a proxy of biomass production (CFAPAR, the cumulative value of FAPAR during the growing season. GSL, SOS and Peak all show different spatial patterns of correlation with CFAPAR. In particular, GSL shows a high and positive correlation with CFAPAR over the whole Sahel (mean r = 0.78. The negative correlation between delays in SOS and CFAPAR is stronger (mean r = −0.71 in the southern agricultural band of the Sahel, while the positive correlation between Peak FAPAR and CFAPAR is higher in the northern and more arid grassland region (mean r = 0.75. The consistency of the results and the actual link between remote sensing-derived phenological parameters and biomass production were evaluated using field measurements of aboveground herbaceous biomass

  1. Seasonal and inter-annual variability in 13C composition of ecosystem carbon fluxes in the U.S. Southern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Torn, M.S.; Biraud, S.; Still, C.J.; Riley, W.J.; Berry, J.A.

    2010-09-22

    The {delta}{sup 13}C signature of terrestrial carbon fluxes ({delta}{sub bio}) provides an important constraint for inverse models of CO{sub 2} sources and sinks, insight into vegetation physiology, C{sub 3} and C{sub 4} vegetation productivity, and ecosystem carbon residence times. From 2002-2009, we measured atmospheric CO{sub 2} concentration and {delta}{sup 13}C-CO{sub 2} at four heights (2 to 60 m) in the U.S. Southern Great Plains (SGP) and computed {delta}{sub bio} weekly. This region has a fine-scale mix of crops (primarily C{sub 3} winter wheat) and C{sub 4} pasture grasses. {delta}{sub bio} had a large and consistent seasonal cycle of 6-8{per_thousand}. Ensemble monthly mean {delta}{sub bio} ranged from -25.8 {+-} 0.4{per_thousand} ({+-}SE) in March to -20.1 {+-} 0.4{per_thousand} in July. Thus, C{sub 3} vegetation contributed about 80% of ecosystem fluxes in winter-spring and 50% in summer-fall. In contrast, prairie-soil {delta}{sub 13}C values were about -15{per_thousand}, indicating that historically the region was dominated by C{sub 4} vegetation and had more positive {delta}{sub bio} values. Based on a land-surface model, isofluxes ({delta}{sub bio} x NEE) in this region have large seasonal amplitude because {delta}{sub bio} and net ecosystem exchange (NEE) covary. Interannual variability in isoflux was driven by variability in NEE. The large seasonal amplitude in {delta}{sub bio} and isoflux imply that carbon inverse analyses require accurate estimates of land cover and temporally resolved {sup 13}CO{sub 2} and CO{sub 2} fluxes.

  2. Effect of climate, intra and inter-annual variability, on nutrients emission (C,N, P) in stream water: lessons from an agricultural long term observatory of the temperate zone

    Science.gov (United States)

    Gascuel-Odoux, Chantal; Remi, Dupas; Patrick, Durand; Ophélie, Fovet; Gerard, Gruau; Anne, Jaffrezic; Guillaume, Humbert; Philippe, Merot; Gu, Sen

    2016-04-01

    Agriculture greatly contributes to modify C, N and P cycles, particularly in animal breeding regions due to high inputs. Climatic conditions, intra and inter-annual variabilities, modify nutrient stream water emissions, acting in time on transfer and transformation, accumulation and mobilization processes, connecting and disconnecting in time different compartments (soil, riparian areas, groundwater). In agricultural catchments, nutrient perturbations are dominated by agricultural land use, and decoupling human activities and climate effects is far from easy. Climate change generally appears as a secondary driver compared to land use. If studied, generally only one nutrient is considered. Only long term, high frequency and multiple element data series can decouple these two drivers. The Kervidy-Naizin watershed belongs to the AgrHyS environmental research observatory (http://www6.inra.fr/ore_agrhys_eng), itself included in RBV (French catchment network of the CZO). On this catchment, 6 years of daily data on DOC, NO3, SRP, TP concentrations allow us to analyze the effect of seasonal and inter-annual climatic variabilities on water quality (C, N, P). Different papers have been published on the effect of climate on nitrate (Molenat et al, 2008), SRP and TP (Dupas et al, 2015) and DOC (Humbert et al, 2015). We will present first results comparing the effect of climate on these three major solute forms of C, N and P. While C and P dynamics are very close and controlled by fluctuation of water table downslope, i.e. in riparian areas, mobilizing C and P in time, nitrate dynamics is controlled by GW dynamics upslope acting as the major N reservoir. As example, the dryness conditions in summer appears a key factor of the C and P emissions in autumn. All the three solute forms interact when anoxic conditions are observed in riparian zones. These basic processes explain how climatic variability can influence and explain interactions between C, N and P emissions in stream

  3. Inter-annual variability of aerosol optical depth over the tropical Atlantic Ocean based on MODIS-Aqua observations over the period 2002-2012

    Science.gov (United States)

    Gkikas, Antonis; Hatzianastassiou, Nikolaos

    2013-04-01

    The tropical Atlantic Ocean is affected by dust and biomass burning aerosol loads transported from the western parts of the Saharan desert and the sub-Sahel regions, respectively. The spatial and temporal patterns of this transport are determined by the aerosol emission rates, their deposition (wet and dry), by the latitudinal shift of the Intertropical Convergence Zone (ITCZ) and the prevailing wind fields. More specifically, in summer, Saharan dust aerosols are transported towards the Atlantic Ocean, even reaching the Gulf of Mexico, while in winter the Atlantic Ocean transport takes place in more southern latitudes, near the equator, sometimes reaching the northern parts of South America. In the later case, dust is mixed with biomass burning aerosols originating from agricultural activities in the sub-Sahel, associated with prevailing north-easterly airflow (Harmattan winds). Satellite observations are the appropriate tool for describing this African aerosol export, which is important to atmospheric, oceanic and climate processes, offering the advantage of complete spatial coverage. In the present study, we use satellite measurements of aerosol optical depth at 550nm (AOD550nm), on a daily and monthly basis, derived from MODIS-Aqua platform, at 1ox1o spatial resolution (Level 3), for the period 2002-2012. The primary objective is to determine the pixel-level and regional mean anomalies of AOD550nm over the entire study period. The regime of the anomalies of African export is interpreted in relation to the aerosol source areas, precipitation, wind patterns and temporal variability of the North Atlantic Oscillation Index (NAOI). In order to ensure availability of AOD over the Sahara desert, MODIS-Aqua Deep Blue products are also used. As for precipitation, Global Precipitation Climatology Project (GPCP) data at 2.5ox2.5o are used. The wind fields are taken from the National Center for Environmental Prediction (NCEP). Apart from the regime of African aerosol export

  4. Inter-Seasonal and Annual Co-Variation of Smallholder Production Portfolios, Volumes and Incomes with Rainfall and Flood Levels in the Amazon Estuary: Implications for Building Livelihood Resilience to Increasing Variability of Hydro-Climatic Regimes

    Science.gov (United States)

    Vogt, N. D.; Fernandes, K.; Pinedo-Vasquez, M.; Brondizio, E. S.; Almeida, O.; Rivero, S.; Rabelo, F. R.; Dou, Y.; Deadman, P.

    2014-12-01

    In this paper we investigate inter-seasonal and annual co-variations of rainfall and flood levels with Caboclo production portfolios, and proportions of it they sell and consume, in the Amazon Estuary from August 2012 to August 2014. Caboclos of the estuary maintain a diverse and flexible land-use portfolio, with a shift in dominant use from agriculture to agroforestry and forestry since WWII (Vogt et al., 2014). The current landscape is configured for acai, shrimp and fish production. In the last decade the frequency of wet seasons with anomalous flood levels and duration has increased primarily from changes in rainfall and discharge from upstream basins. Local rainfall, though with less influence on extreme estuarine flood levels, is reported to be more sporadic and intense in wet season and variable in both wet and dry seasons, for yet unknown reasons. The current production portfolio and its flexibility are felt to build resilience to these increases in hydro-climatic variability and extreme events. What is less understood, for time and costliness of daily measures at household levels, is how variations in flood and rainfall levels affect shifts in the current production portfolio of estuarine Caboclos, and the proportions of it they sell and consume. This is needed to identify what local hydro-climatic thresholds are extreme for current livelihoods, that is, that most adversely affect food security and income levels. It is also needed identify the large-scale forcings driving those extreme conditions to build forecasts for when they will occur. Here we present results of production, rainfall and flood data collected daily in households from both the North and South Channel of the Amazon estuary over last two years to identify how they co-vary, and robustness of current production portfolio under different hydro-climatic conditions.

  5. Black sea annual and inter-annual water mass variations from space

    DEFF Research Database (Denmark)

    Yildiz, H.; Andersen, Ole Baltazar; Simav, M.

    2011-01-01

    This study evaluates the performance of two widely used GRACE solutions (CNES/GRGS RL02 and CSR RL04) in deriving annual and inter-annual water mass variations in the Black Sea for the period 2003–2007. It is demonstrated that the GRACE derived water mass variations in the Black Sea are heavily i...

  6. Global inter-annual gravity changes from GRACE: Early results

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Hinderer, J.

    2005-01-01

    Fifteen monthly gravity field solutions from the GRACE twin satellites launched more than two years ago have been studied to estimate gravity field changes between 2002 and 2003. The results demonstrate that GRACE is capable of capturing the changes in ground water on inter-annual scales...... with an accuracy of 0.4 muGal corresponding to 9 mm water thickness on spatial scales longer than 1300 km. Four of the most widely used global hydrological models have been investigated for their spatial comparison with GRACE observations of inter-annual gravity field variations due to changes in continental water...... storage. The Global Land Data Assimilation System model has a spatial correlation coefficient with GRACE observations of 0.65 over the northern hemisphere. This demonstrates that the observed gravity field changes on these scales are largely related to changes in continental water storage....

  7. Inter-Trial Gait Variability Reduction Using Continous Curve Registration

    National Research Council Canada - National Science Library

    Sadeghi, H

    2001-01-01

    Timing in peak gait values shifts slightly between gait trials. When gait data are averaged, some of the standard deviation can be associated to this inter-trial variability unless normalization is carried out beforehand...

  8. Seasonal and inter-annual variability of aerosol optical properties during 2005-2010 over Red Mountain Pass and Impact on the Snow Cover of the San Juan Mountains

    Science.gov (United States)

    Singh, R. P.; Gautam, R.; Painter, T. H.

    2011-12-01

    Growing body of evidence suggests the significant role of aerosol solar absorption in accelerated seasonal snowmelt in the cryosphere and elevated mountain regions via snow contamination and radiative warming processes. Characterization of aerosol optical properties over seasonal snow cover and snowpacks is therefore important towards the better understanding of aerosol radiative effects and associated impact on snow albedo. In this study, we present seasonal variations in column-integrated aerosol optical properties retrieved from AERONET sunphotometer measurements (2005-2010) at Red Mountain Pass (37.90° N, 107.72° W, 3368 msl) in the San Juan Mountains, in the vicinity of the North American Great Basin and Colorado Plateau deserts. The aerosol optical depth (AOD) measured at 500nm is generally low (pollutant transport. In addition, the possibility of the observed increased coarse-mode influence associated with mineral dust influx cannot be ruled out, due to westerly-airmass driven transport from arid/desert regions as suggested by backward trajectory simulations. A meteorological coupling is also found in the summer season between AOD and column water vapor retrieved from AERONET with co-occurring enhanced water vapor and AOD. Based on column measurements, it is difficult to ascertain the aerosol composition, however, the summer-time enhanced aerosol loading as presented here is consistent with the increased dust deposition in the San Juan mountain snow cover as reported in recent studies. In summary, this study is expected to better understand the seasonal and inter-annual aerosol column variations and is an attempt to provide an insight into the effects of aerosol solar absorption on accelerated seasonal snowmelt in the San Juan mountains.

  9. Multi-tissue analyses reveal limited inter-annual and seasonal variation in mercury exposure in an Antarctic penguin community.

    Science.gov (United States)

    Brasso, Rebecka L; Polito, Michael J; Emslie, Steven D

    2014-10-01

    Inter-annual variation in tissue mercury concentrations in birds can result from annual changes in the bioavailability of mercury or shifts in dietary composition and/or trophic level. We investigated potential annual variability in mercury dynamics in the Antarctic marine food web using Pygoscelis penguins as biomonitors. Eggshell membrane, chick down, and adult feathers were collected from three species of sympatrically breeding Pygoscelis penguins during the austral summers of 2006/2007-2010/2011. To evaluate the hypothesis that mercury concentrations in penguins exhibit significant inter-annual variation and to determine the potential source of such variation (dietary or environmental), we compared tissue mercury concentrations with trophic levels as indicated by δ(15)N values from all species and tissues. Overall, no inter-annual variation in mercury was observed in adult feathers suggesting that mercury exposure, on an annual scale, was consistent for Pygoscelis penguins. However, when examining tissues that reflected more discrete time periods (chick down and eggshell membrane) relative to adult feathers, we found some evidence of inter-annual variation in mercury exposure during penguins' pre-breeding and chick rearing periods. Evidence of inter-annual variation in penguin trophic level was also limited suggesting that foraging ecology and environmental factors related to the bioavailability of mercury may provide more explanatory power for mercury exposure compared to trophic level alone. Even so, the variable strength of relationships observed between trophic level and tissue mercury concentrations across and within Pygoscelis penguin species suggest that caution is required when selecting appropriate species and tissue combinations for environmental biomonitoring studies in Antarctica.

  10. Interaction of Socio-Demographic Background Variables with Inter ...

    African Journals Online (AJOL)

    Interaction of Socio-Demographic Background Variables with Inter-Spousal Communication Among Married Couples in Alimosho Local Government Area of Lagos State, Nigeria. ... marriage will increase from 20-24years to 25-29years due to the number of years of couple's educational pursuit in Lagos state of Nigeria.

  11. Atmospheric forcing controlling inter-annual nutrient dynamics in the open Gulf of Finland

    Science.gov (United States)

    Lehtoranta, Jouni; Savchuk, Oleg P.; Elken, Jüri; Dahlbo, Kim; Kuosa, Harri; Raateoja, Mika; Kauppila, Pirkko; Räike, Antti; Pitkänen, Heikki

    2017-07-01

    The loading of P into the Gulf of Finland has decreased markedly, but no overall trend in the concentration of P has been observed in the open Gulf, where the concentrations of both inorganic N and P still have a pronounced inter-annual variability. Our main aim was to study whether the internal processes driven by atmospheric forcing can explain the variation in the nutrient conditions in the Gulf during the period 1992-2014. We observed that the long-term salinity variation of the bottom water in the northern Baltic Proper controls that in the Gulf, and that the deep-water concentrations of oxygen and nutrients are significantly correlated between the basins. This imposes preconditions regarding how atmospheric forcing may influence deep water flows and stratification in the Gulf on a long-term scale. We found that over short timescales, winter winds in particular can control the in- and outflows of water and the vertical stratification and mixing, which to a large extent explained the inter-annual variation in the DIN and TP pools in the Gulf. We conclude that the inter-annual variation in the amounts, ratios, and spatial distribution of nutrients sets variable preconditions for the spring and potential blue-green algae blooms, and that internal processes were able to mask the effects of the P load reductions implemented across the whole Gulf. The transportation of P along the bottom from the northern Baltic Proper and its evident uplift in the Gulf highlights the fact that the nutrient reductions are also needed in the entire catchment of the Baltic Sea to improve the trophic status of the open Gulf.

  12. Long term (2006-2016) seasonal and inter-annual variability of soil electrical resistivity in a Laotian catchment of the OZCAR network. Impact of land use change, soil type and rainfall

    Science.gov (United States)

    Robain, Henri; Ribolzi, Olivier; De Rouw, Anneke; Silvera, Norbert; Souniaphong, Phabvilay; Soulileuth, Bousamai; Latchasak, Keooudone; Sengtaheuanghoung, Oloth; Valentin, Christian; Gaillardet, Jerome

    2017-04-01

    The MSEC(1) observatory of the critical zone in south-east Asia, which is part of the OZCAR(2) Network, has been monitored since 1999 (Laos, Thailand, Vietnam) to study the long term impact of land use changes in tropical mountainous regions, in terms of soil properties (porosity, depth, SOC, nutrients…), biodiversity (weeds, soil macro fauna), plant roots (architecture, functions,…), and transfers within the critical zone at various temporal and space scales: partition between infiltration and runoff, water quality (physical, chemical and bacteriological) and erosion processes (splash, inter-rill and rill, tillage, mass-movement). In the Houay Pano catchment located in Northern Laos, a long-term monitoring system was implemented in 2006 combining Electrical Resistivity Tomography (ERT), with soil and hydrological equipments to better analyse the interactions between bank and hillslopes groundwater, and streamwater, in a context of steep slopes (>50%) and rapid land use change (conversion of annual crops to teak plantation). This continuous ERT monitoring has been carried out along a representative 100 m long transect in the middle of the 65 ha catchment perpendicular to the stream. The data were collected every week during rainy season and every second week during dry season. It has been associated with hydrological monitoring (piezometers, limnimeters, gauging weirs). Such high resolution geophysical monitoring data set (approx. 900 apparent resistivity measurements for each acquisition) provides an invaluable non-invasive proxy of soil water content variations in the different layers of the vadose zone. It demonstrates: i) the influence of plant cover on water infiltration; ii) the pathways for vertical and horizontal water fluxes within the soil cover; iii) the control of soil organisation along the hillslope over the hydrological behaviour of the unsaturated part of the critical zone. (1) «Multi-Scale Environmental Changes» : http://msec.obs-mip.fr/ (2

  13. Sensitivity of inter-annual variation of CO2 seasonal cycle at Mauna Loa to atmospheric transport

    International Nuclear Information System (INIS)

    Taguchi, Shoichi; Murayama, Shohei; Higuchi, Kaz

    2003-01-01

    Origins of the inter-annual variations of the Mauna Loa atmospheric CO 2 seasonal cycle related to atmospheric transport were examined using a global atmospheric transport model with prescribed land biota CO 2 source functions at 11 land sections. On average, the seasonal variation of atmospheric CO 2 at Mauna Loa is influenced mostly by the Siberian CO 2 flux, followed by temperate Asia and North America. The inter-annual variability of the seasonal cycle is caused mainly by the inter-annual variation in the transport of the Siberian signal to Mauna Loa. The characteristics of the simulated seasonal cycle and its inter-annual variability at Mauna Loa are found to be sensitive to the quality of the wind data used to drive the transport model. Implication of this result is that for studying a long-term variations of atmospheric transport a meteorological data set for driving an atmospheric transport model should be obtained from the same production procedure

  14. Inter-individual cognitive variability in children with Asperger's syndrome

    OpenAIRE

    Gonzalez-Gadea, Maria Luz; Tripicchio, Paula; Rattazzi, Alexia; Baez, Sandra; Marino, Julian; Roca, Maria; Manes, Facundo; Ibanez, Agustin

    2014-01-01

    Multiple studies have tried to establish the distinctive profile of individuals with Asperger's syndrome (AS). However, recent reports suggest that adults with AS feature heterogeneous cognitive profiles. The present study explores inter-individual variability in children with AS through group comparison and multiple case series analysis. All participants completed an extended battery including measures of fluid and crystallized intelligence, executive functions, theory of mind, and classical...

  15. How does the terrestrial carbon exchange respond to inter-annual climatic variations? A quantification based on atmospheric CO2 data

    Science.gov (United States)

    Rödenbeck, Christian; Zaehle, Sönke; Keeling, Ralph; Heimann, Martin

    2018-04-01

    The response of the terrestrial net ecosystem exchange (NEE) of CO2 to climate variations and trends may crucially determine the future climate trajectory. Here we directly quantify this response on inter-annual timescales by building a linear regression of inter-annual NEE anomalies against observed air temperature anomalies into an atmospheric inverse calculation based on long-term atmospheric CO2 observations. This allows us to estimate the sensitivity of NEE to inter-annual variations in temperature (seen as a climate proxy) resolved in space and with season. As this sensitivity comprises both direct temperature effects and the effects of other climate variables co-varying with temperature, we interpret it as inter-annual climate sensitivity. We find distinct seasonal patterns of this sensitivity in the northern extratropics that are consistent with the expected seasonal responses of photosynthesis, respiration, and fire. Within uncertainties, these sensitivity patterns are consistent with independent inferences from eddy covariance data. On large spatial scales, northern extratropical and tropical inter-annual NEE variations inferred from the NEE-T regression are very similar to the estimates of an atmospheric inversion with explicit inter-annual degrees of freedom. The results of this study offer a way to benchmark ecosystem process models in more detail than existing effective global climate sensitivities. The results can also be used to gap-fill or extrapolate observational records or to separate inter-annual variations from longer-term trends.

  16. Inter-observer and inter-examination variability of manual vertebral bone attenuation measurements on computed tomography

    International Nuclear Information System (INIS)

    Pompe, Esther; Lammers, Jan-Willem J.; Jong, Pim A. de; Jong, Werner U. de; Takx, Richard A.P.; Eikendal, Anouk L.M.; Willemink, Martin J.; Mohamed Hoesein, Firdaus A.A.; Oudkerk, Matthijs; Budde, Ricardo P.J.

    2016-01-01

    To determine inter-observer and inter-examination variability of manual attenuation measurements of the vertebrae in low-dose unenhanced chest computed tomography (CT). Three hundred and sixty-seven lung cancer screening trial participants who underwent baseline and repeat unenhanced low-dose CT after 3 months because of an indeterminate lung nodule were included. The CT attenuation value of the first lumbar vertebrae (L1) was measured in all CTs by one observer to obtain inter-examination reliability. Six observers performed measurements in 100 randomly selected CTs to determine agreement with limits of agreement and Bland-Altman plots and reliability with intraclass correlation coefficients (ICCs). Reclassification analyses were performed using a threshold of 110 HU to define osteoporosis. Inter-examination reliability was excellent with an ICC of 0.92 (p < 0.001). Inter-examination limits of agreement ranged from -26 to 28 HU with a mean difference of 1 ± 14 HU. Inter-observer reliability ICCs ranged from 0.70 to 0.91. Inter-examination variability led to 11.2 % reclassification of participants and inter-observer variability led to 22.1 % reclassification. Vertebral attenuation values can be manually quantified with good to excellent inter-examination and inter-observer reliability on unenhanced low-dose chest CT. This information is valuable for early detection of osteoporosis on low-dose chest CT. (orig.)

  17. Inter-annual trends of heavy metals in marine resources from the ...

    African Journals Online (AJOL)

    USER

    In an attempt to monitor and assess the pollution status of marine resources in the Nigerian territorial waters, this study was carried out to reveal the levels and inter-annual trend of heavy metals in marine resources from the Lagos lagoon marine ecosystem. Studies were carried out annually in the month of. July between ...

  18. Inter-annual trends of heavy metals in marine resources from the ...

    African Journals Online (AJOL)

    In an attempt to monitor and assess the pollution status of marine resources in the Nigerian territorial waters, this study was carried out to reveal the levels and inter-annual trend of heavy metals in marine resources from the Lagos lagoon marine ecosystem. Studies were carried out annually in the month of July between ...

  19. Minimizing inter-microscope variability in dental microwear texture analysis

    Science.gov (United States)

    Arman, Samuel D.; Ungar, Peter S.; Brown, Christopher A.; DeSantis, Larisa R. G.; Schmidt, Christopher; Prideaux, Gavin J.

    2016-06-01

    A common approach to dental microwear texture analysis (DMTA) uses confocal profilometry in concert with scale-sensitive fractal analysis to help understand the diets of extinct mammals. One of the main benefits of DMTA over other methods is the repeatable, objective manner of data collection. This repeatability, however, is threatened by variation in results of DMTA of the same dental surfaces yielded by different microscopes. Here we compare DMTA data of five species of kangaroos measured on seven profilers of varying specifications. Comparison between microscopes confirms that inter-microscope differences are present, but we show that deployment of a number of automated treatments to remove measurement noise can help minimize inter-microscope differences. Applying these same treatments to a published hominin DMTA dataset shows that they alter some significant differences between dietary groups. Minimising microscope variability while maintaining interspecific dietary differences requires then that these factors are balanced in determining appropriate treatments. The process outlined here offers a solution for allowing comparison of data between microscopes, which is essential for ongoing DMTA research. In addition, the process undertaken, including considerations of other elements of DMTA protocols also promises to streamline methodology, remove measurement noise and in doing so, optimize recovery of a reliable dietary signature.

  20. Climate and the inter-annual variability of fire in southern Africa: a meta-analysis using long-term field data and satellite-derived burnt area data

    CSIR Research Space (South Africa)

    Archibald, S

    2010-11-01

    Full Text Available -sensed burned area data to test whether it is possible to develop a general model. Location: Africa south of the equator Methods: Linear mixed e ects models were used to determine the e ect of rainfall, season- ality, and re weather in driving variation... in re extent between years, and to test whether the e ect of these variables changes across the sub-continent, and in areas more and less impacted by human activities. Results: A simple model including rainfall and seasonality explained 40...

  1. Micro-phytoplankton community structure in the coastal upwelling zone off Concepción (central Chile): Annual and inter-annual fluctuations in a highly dynamic environment

    Science.gov (United States)

    Anabalón, V.; Morales, C. E.; González, H. E.; Menschel, E.; Schneider, W.; Hormazabal, S.; Valencia, L.; Escribano, R.

    2016-12-01

    An intensification of upwelling-favorable winds in recent decades has been detected in some of the main eastern boundary current systems, especially at higher latitudes, but the response of coastal phytoplankton communities in the Humboldt Current System (HCS) remains unknown. At higher latitudes in the HCS (35-40°S), strong seasonality in wind-driven upwelling during spring-summer coincides with an annual increase in coastal chlorophyll-a and primary production, and a dominance of micro-phytoplankton. In order to understand the effects of potential upwelling intensification on the micro-phytoplankton community in this region, annual and inter-annual variability in its structure (total and taxa-specific abundance and biomass) and its association with oceanographic fluctuations were analyzed using in situ time series data (2002-2009) from a shelf station off Concepcion (36.5°S). At the annual scale, total mean abundance and biomass, attributed to a few dominant diatom taxa, were at least one order of magnitude greater during spring-summer than autumn-winter, in association with changes in upwelling and surface salinity and temperature, whereas macro-nutrient concentrations remained relatively high all the year. At the inter-annual scale, total abundance and biomass decreased during the upwelling season of the 2006-2009 period compared with the 2002-2006 period, notably due to lower abundances of Skeletonema and Leptocylindrus, but the relative dominance of a few taxa was maintained. The 2006-2009 period was characterized by higher upwelling intensity, colder and higher salinity waters, and changes in nutrient concentrations and ratios compared with the first period. The inter-annual changes in the micro-phytoplankton community were mostly associated with changes in surface salinity and temperature (changes in upwelling intensity) but also with changes in Si/N and N/P, which relate to other land-derived processes.

  2. Inter-annual variations in wave characteristics off Ratnagiri, Northeast Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Johnson, G.; SanilKumar, V.; Singh, J.

    The wave data measured using the Datawell directional wave rider buoy at 13 m water depth off Ratnagiri during 2010 to 2013 is used to study the inter-annual variations in the wave characteristics. The percentage occurrence of waves with significant...

  3. Solar induced inter-annual variability of ozone

    Science.gov (United States)

    Fytterer, Tilo; Nieder, Holger; Perot, Kristell; Sinnhuber, Miriam; Stiller, Gabriele; Urban, Joachim

    2014-05-01

    Measurements by the Michelson Interferometer for Passive Atmospheric Sounding instrument on board the ENVIromental SATellite from 2005 - 2011 are used to investigate the impact of solar and geomagnetic activity on O3 in the stratosphere and mesosphere inside the Antarctic polar vortex. It is known from observations that energetic particles, mainly originating from the sun, precipitate in the Earth atmosphere and produce odd nitrogen NOx (N + NO + NO2) in the upper mesosphere and lower thermosphere, which is transported downwards into the stratosphere during polar winter. Results from global chemistry-transport models suggest that this leads to a depletion of O3 down to ~30 km at high latitudes during winter. Therefore it appears promising to search for a link between high energetic particles and O3 in actual data sets. Thus in this study, correlation analysis between a 26 days average centred around 1 Apr, 1 May and 1 Jun of several solar/geomagnetic indices (Ap index, F10.7 cm solar radio flux, Lyman-alpha, 2 MeV electrons flux) and 26 day running means from 1 Apr - 1 Nov of O3 in the altitude range from 20 - 70 km were performed. The results reveal negative correlation coefficients propagating downwards throughout the polar winter, at least for the Ap index and the 2 MeV electrons flux. Comparisons with TIMED/SABER and Odin/SMR O3 data are in moderate agreement, also showing a descending negative signal in either indices, but only for the correlation with 1 Apr.

  4. Inter-annual rainfall variability and droughts occurrence during ...

    African Journals Online (AJOL)

    This study examined the trends of rainfall and the intensity of drought during sowing season and mid-season of rice farming calendar in the rainforest belt of Nigeria using data spanning 52 years (1961-2012) for five synoptic weather stations. The trends were investigated using simple linear regression and second order ...

  5. Seasonal and inter-annual photosynthetic response of representative C4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain

    NARCIS (Netherlands)

    Mantlana, K.B.; Arneth, A.; Veenendaal, E.M.; Wohland, P.; Wolski, P.; Kolle, O.; Lloyd, J.

    2008-01-01

    We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants

  6. Skilful prediction of Sahel summer rainfall on inter-annual and multi-year timescales.

    Science.gov (United States)

    Sheen, K L; Smith, D M; Dunstone, N J; Eade, R; Rowell, D P; Vellinga, M

    2017-05-25

    Summer rainfall in the Sahel region of Africa exhibits one of the largest signals of climatic variability and with a population reliant on agricultural productivity, the Sahel is particularly vulnerable to major droughts such as occurred in the 1970s and 1980s. Rainfall levels have subsequently recovered, but future projections remain uncertain. Here we show that Sahel rainfall is skilfully predicted on inter-annual and multi-year (that is, >5 years) timescales and use these predictions to better understand the driving mechanisms. Moisture budget analysis indicates that on multi-year timescales, a warmer north Atlantic and Mediterranean enhance Sahel rainfall through increased meridional convergence of low-level, externally sourced moisture. In contrast, year-to-year rainfall levels are largely determined by the recycling rate of local moisture, regulated by planetary circulation patterns associated with the El Niño-Southern Oscillation. Our findings aid improved understanding and forecasting of Sahel drought, paramount for successful adaptation strategies in a changing climate.

  7. Inter-annual Variations of the Carbon Footprint in Beijing Tianjin and Hebei Agro-ecosystem

    Directory of Open Access Journals (Sweden)

    TIAN Zhi-hui

    2018-02-01

    Full Text Available Based on the integration of Beijing, Tianjin and Hebei, we investigated inter-annual changes in carbon footprint from 2005 to 2014 in the agro-ecosystem of suburban Beijing Tianjin and Hebei. Our findings indicated that:(1 Carbon sink decreased 6.6 percent annually. The average annual carbon storage amount was 4 855 000 tons, with food crops constituting the highest proportion;(2 Carbon emission in the system showed a gradually decreasing trend, with agricultural chemicals as significant contributors. The annual average carbon emission was 7 278 000 tons in the Beijing Tianjin and Hebei farmland ecosystem. The largest amount of carbon emissions came from agricultural chemicals, nitrogen(from fertilizerwas the biggest contributor;(3 The average carbon footprint was 1 612 000 hm2 in the Beijing Tianjin and Hebei farmland ecosystem and showed a decreasing trend along with an ecological surplus of carbon.

  8. Links between annual, Milankovitch and continuum temperature variability.

    Science.gov (United States)

    Huybers, Peter; Curry, William

    2006-05-18

    Climate variability exists at all timescales-and climatic processes are intimately coupled, so that understanding variability at any one timescale requires some understanding of the whole. Records of the Earth's surface temperature illustrate this interdependence, having a continuum of variability following a power-law scaling. But although specific modes of interannual variability are relatively well understood, the general controls on continuum variability are uncertain and usually described as purely stochastic processes. Here we show that power-law relationships of surface temperature variability scale with annual and Milankovitch-period (23,000- and 41,000-year) cycles. The annual cycle corresponds to scaling at monthly to decadal periods, while millennial and longer periods are tied to the Milankovitch cycles. Thus the annual, Milankovitch and continuum temperature variability together represent the response to deterministic insolation forcing. The identification of a deterministic control on the continuum provides insight into the mechanisms governing interannual and longer-period climate variability.

  9. Quantification of Impact of Orbital Drift on Inter-Annual Trends in AVHRR NDVI Data

    Directory of Open Access Journals (Sweden)

    Jyoteshwar R. Nagol

    2014-07-01

    Full Text Available The Normalized Difference Vegetation Index (NDVI time-series data derived from Advanced Very High Resolution Radiometer (AVHRR have been extensively used for studying inter-annual dynamics of global and regional vegetation. However, there can be significant uncertainties in the data due to incomplete atmospheric correction and orbital drift of the satellites through their active life. Access to location specific quantification of uncertainty is crucial for appropriate evaluation of the trends and anomalies. This paper provides per pixel quantification of orbital drift related spurious trends in Long Term Data Record (LTDR AVHRR NDVI data product. The magnitude and direction of the spurious trends was estimated by direct comparison with data from MODerate resolution Imaging Spectrometer (MODIS Aqua instrument, which has stable inter-annual sun-sensor geometry. The maps show presence of both positive as well as negative spurious trends in the data. After application of the BRDF correction, an overall decrease in positive trends and an increase in number of pixels with negative spurious trends were observed. The mean global spurious inter-annual NDVI trend before and after BRDF correction was 0.0016 and −0.0017 respectively. The research presented in this paper gives valuable insight into the magnitude of orbital drift related trends in the AVHRR NDVI data as well as the degree to which it is being rectified by the MODIS BRDF correction algorithm used by the LTDR processing stream.

  10. Localised residency and inter-annual fidelity to coastal foraging areas may place sea bass at risk to local depletion.

    Science.gov (United States)

    Doyle, Thomas K; Haberlin, Damien; Clohessy, Jim; Bennison, Ashley; Jessopp, Mark

    2017-04-04

    For many marine migratory fish, comparatively little is known about the movement of individuals rather than the population. Yet, such individual-based movement data is vitally important to understand variability in migratory strategies and fidelity to foraging locations. A case in point is the economically important European sea bass (Dicentrarchus labrax L.) that inhabits coastal waters during the summer months before migrating offshore to spawn and overwinter. Beyond this broad generalisation we have very limited information on the movements of individuals at coastal foraging grounds. We used acoustic telemetry to track the summer movements and seasonal migrations of individual sea bass in a large tidally and estuarine influenced coastal environment. We found that the vast majority of tagged sea bass displayed long-term residency (mean, 167 days) and inter-annual fidelity (93% return rate) to specific areas. We describe individual fish home ranges of 3 km or less, and while fish clearly had core resident areas, there was movement of fish between closely located receivers. The combination of inter-annual fidelity to localised foraging areas makes sea bass very susceptible to local depletion; however, the designation of protected areas for sea bass may go a long way to ensuring the sustainability of this species.

  11. Projecting pest population dynamics under global warming: the combined effect of inter- and intra-annual variations.

    Science.gov (United States)

    Zidon, Royi; Tsueda, Hirotsugu; Morin, Efrat; Morin, Shai

    2016-06-01

    The typical short generation length of insects makes their population dynamics highly sensitive not only to mean annual temperatures but also to their intra-annual variations. To consider the combined effect of both thermal factors under global warming, we propose a modeling framework that links general circulation models (GCMs) with a stochastic weather generator and population dynamics models to predict species population responses to inter- and intra-annual temperature changes. This framework was utilized to explore future changes in populations of Bemisia tabaci, an invasive insect pest-species that affects multiple agricultural systems in the Mediterranean region. We considered three locations representing different pest status and climatic conditions: Montpellier (France), Seville (Spain), and Beit-Jamal (Israel). We produced ensembles of local daily temperature realizations representing current and future (mid-21st century) climatic conditions under two emission scenarios for the three locations. Our simulations predicted a significant increase in the average number of annual generations and in population size, and a significant lengthening of the growing season in all three locations. A negative effect was found only in Seville for the summer season, where future temperatures lead to a reduction in population size. High variability in population size was observed between years with similar annual mean temperatures, suggesting a strong effect of intra-annual temperature variation. Critical periods were from late spring to late summer in Montpellier and from late winter to early summer in Seville and Beit-Jamal. Although our analysis suggested that earlier seasonal activity does not necessarily lead to increased populations load unless an additional generation is produced, it is highly likely that the insect will become a significant pest of open-fields at Mediterranean latitudes above 40° during the next 50 years. Our simulations also implied that current

  12. Large inter annual variation in air quality during the annual festival 'Diwali' in an Indian megacity.

    Science.gov (United States)

    Parkhi, Neha; Chate, Dilip; Ghude, Sachin D; Peshin, Sunil; Mahajan, Anoop; Srinivas, Reka; Surendran, Divya; Ali, Kaushar; Singh, Siddhartha; Trimbake, Hanumant; Beig, Gufran

    2016-05-01

    A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research (SAFAR) project in Delhi. We report observations of ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM2.5 and PM10) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM10 and PM2.5 mass concentration is as high as 2070µg/m3 and 1620μg/m(3), respectively (24hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards (NAAQS). For Diwali-2011, the increase in PM10 and PM2.5 mass concentrations was much less with their peaks of 600 and of 390μg/m(3) respectively, as compared to the background concentrations. Contrary to previous reports, firework display was not found to strongly influence the NOx, and O3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters. Copyright © 2015. Published by Elsevier B.V.

  13. Inter-annual cascade effect on marine food web: A benthic pathway lagging nutrient supply to pelagic fish stock.

    Directory of Open Access Journals (Sweden)

    Lohengrin Dias de Almeida Fernandes

    Full Text Available Currently, spatial and temporal changes in nutrients availability, marine planktonic, and fish communities are best described on a shorter than inter-annual (seasonal scale, primarily because the simultaneous year-to-year variations in physical, chemical, and biological parameters are very complex. The limited availability of time series datasets furnishing simultaneous evaluations of temperature, nutrients, plankton, and fish have limited our ability to describe and to predict variability related to short-term process, as species-specific phenology and environmental seasonality. In the present study, we combine a computational time series analysis on a 15-year (1995-2009 weekly-sampled time series (high-resolution long-term time series, 780 weeks with an Autoregressive Distributed Lag Model to track non-seasonal changes in 10 potentially related parameters: sea surface temperature, nutrient concentrations (NO2, NO3, NH4 and PO4, phytoplankton biomass (as in situ chlorophyll a biomass, meroplankton (barnacle and mussel larvae, and fish abundance (Mugil liza and Caranx latus. Our data demonstrate for the first time that highly intense and frequent upwelling years initiate a huge energy flux that is not fully transmitted through classical size-structured food web by bottom-up stimulus but through additional ontogenetic steps. A delayed inter-annual sequential effect from phytoplankton up to top predators as carnivorous fishes is expected if most of energy is trapped into benthic filter feeding organisms and their larval forms. These sequential events can explain major changes in ecosystem food web that were not predicted in previous short-term models.

  14. Millennium-scale crossdating and inter-annual climate sensitivities of standing California redwoods.

    Directory of Open Access Journals (Sweden)

    Allyson L Carroll

    Full Text Available Extremely decay-resistant wood and fire-resistant bark allow California's redwoods to accumulate millennia of annual growth rings that can be useful in biological research. Whereas tree rings of Sequoiadendron giganteum (SEGI helped formalize the study of dendrochronology and the principle of crossdating, those of Sequoia sempervirens (SESE have proven much more difficult to decipher, greatly limiting dendroclimatic and other investigations of this species. We overcame these problems by climbing standing trees and coring trunks at multiple heights in 14 old-growth forest locations across California. Overall, we sampled 1,466 series with 483,712 annual rings from 120 trees and were able to crossdate 83% of SESE compared to 99% of SEGI rings. Standard and residual tree-ring chronologies spanning up to 1,685 years for SESE and 1,538 years for SEGI were created for each location to evaluate crossdating and to examine correlations between annual growth and climate. We used monthly values of temperature, precipitation, and drought severity as well as summer cloudiness to quantify potential drivers of inter-annual growth variation over century-long time series at each location. SESE chronologies exhibited a latitudinal gradient of climate sensitivities, contrasting cooler northern rainforests and warmer, drier southern forests. Radial growth increased with decreasing summer cloudiness in northern rainforests and a central SESE location. The strongest dendroclimatic relationship occurred in our southernmost SESE location, where radial growth correlated negatively with dry summer conditions and exhibited responses to historic fires. SEGI chronologies showed negative correlations with June temperature and positive correlations with previous October precipitation. More work is needed to understand quantitative relationships between SEGI radial growth and moisture availability, particularly snowmelt. Tree-ring chronologies developed here for both redwood

  15. Variability of annual CO2 exchange from Dutch grasslands

    Directory of Open Access Journals (Sweden)

    A. Schrier-Uijl

    2007-10-01

    Full Text Available An intercomparison is made of the Net Ecosystem Exchange of CO2, NEE, for eight Dutch grassland sites: four natural grasslands, two production grasslands and two meteorological stations within a rotational grassland region. At all sites the NEE was determined during at least 10 months per site, using the eddy-covariance (EC technique, but in different years. The NEE does not include any import or export other than CO2. The photosynthesis-light response analysis technique is used along with the respiration-temperature response technique to partition NEE into Gross Primary Production (GPP and Ecosystem Respiration (Re and to obtain the eco-physiological characteristics of the sites at the field scale. Annual sums of NEE, GPP and Re are then estimated using the fitted response curves with observed radiation and air temperature from a meteorological site in the centre of The Netherlands as drivers. These calculations are carried out for four years (2002–2005. Land use and management histories are not considered. The estimated annual Re for all individual sites is more or less constant per site and the average for all sites amounts to 1390±30 gC m−2 a−1. The narrow uncertainty band (±2% reflects the small differences in the mean annual air temperature. The mean annual GPP was estimated to be 1325 g C m−2 a−1, and displays a much higher standard deviation, of ±110 gC m−2 a−1 (8%, which reflects the relatively large variation in annual solar radiation. The mean annual NEE amounts to –65±85 gC m−2 a−1. From two sites, four-year records of CO2 flux were available and analyzed (2002–2005. Using the weather record of 2005 with optimizations from the other years, the standard deviation of annual GPP was estimated to be 171–206 gC m−2 a−1 (8–14%, of annual Re 227–247 gC m−2 a−1 (14–16% and of annual NEE 176–276 gC m−2 a−1. The inter-site standard deviation was higher for GPP and Re, 534 gC m−2 a−1 (37

  16. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R.J.; Muller, S.H.; Vincent, A.; Sinaasappel, M.; Zuur, J.K.; Hilgers, F.J.M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P <

  17. Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

    NARCIS (Netherlands)

    Scheenstra, R. J.; Muller, S. H.; Vincent, A.; Sinaasappel, M.; Zuur, J. K.; Hilgers, Frans J. M.

    2009-01-01

    This study assesses intra- and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P

  18. Studies on inter-speaker variability in speech and its application in ...

    Indian Academy of Sciences (India)

    independent. ASR systems. ... In this review article, we study the variability in the acoustic signal among different speakers enunciating the ... review paper, we will describe two standard procedures that are used to reduce inter-speaker vari- ations to ...

  19. Studies on inter-speaker variability in speech and its application in ...

    Indian Academy of Sciences (India)

    We then describe the universal-warping approach to speaker normalization which unifies many of the vowel normalization approaches and also shows the relation between speech production, perception and auditory processing. We then address the problem of inter-speaker variability in automatic speech recognition ...

  20. Inter- and intra-laboratory variability of CD4 cell counts in Swaziland

    African Journals Online (AJOL)

    2012-06-01

    Jun 1, 2012 ... techniques and found to be comparable.3,4,8. ORIGINAL ARTICLE. Inter- and intra-laboratory variability of CD4 cell counts in Swaziland. Ganizani Mlawanda, MB ChB, MSc Clinical Epidemiology, Dip HIV Man, DTM&H. School of Health Systems and Public Health, Faculty of Health Sciences, University of ...

  1. Inter- and intra-laboratory variability of CD4 cell counts in Swaziland

    African Journals Online (AJOL)

    2012-06-01

    Jun 1, 2012 ... Inter- and intra-laboratory variability of CD4 cell counts in Swaziland. Ganizani Mlawanda, MB ChB, MSc Clinical Epidemiology, Dip HIV Man, DTM&H. School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, and Royal Swaziland. Sugar Corporation Medical Services ...

  2. Cardiac valve calcifications on low-dose unenhanced ungated chest computed tomography: inter-observer and inter-examination reliability, agreement and variability

    International Nuclear Information System (INIS)

    Hamersvelt, Robbert W. van; Willemink, Martin J.; Takx, Richard A.P.; Eikendal, Anouk L.M.; Budde, Ricardo P.J.; Leiner, Tim; Jong, Pim A. de; Mol, Christian P.; Isgum, Ivana

    2014-01-01

    To determine inter-observer and inter-examination variability for aortic valve calcification (AVC) and mitral valve and annulus calcification (MC) in low-dose unenhanced ungated lung cancer screening chest computed tomography (CT). We included 578 lung cancer screening trial participants who were examined by CT twice within 3 months to follow indeterminate pulmonary nodules. On these CTs, AVC and MC were measured in cubic millimetres. One hundred CTs were examined by five observers to determine the inter-observer variability. Reliability was assessed by kappa statistics (κ) and intra-class correlation coefficients (ICCs). Variability was expressed as the mean difference ± standard deviation (SD). Inter-examination reliability was excellent for AVC (κ = 0.94, ICC = 0.96) and MC (κ = 0.95, ICC = 0.90). Inter-examination variability was 12.7 ± 118.2 mm 3 for AVC and 31.5 ± 219.2 mm 3 for MC. Inter-observer reliability ranged from κ = 0.68 to κ = 0.92 for AVC and from κ = 0.20 to κ = 0.66 for MC. Inter-observer ICC was 0.94 for AVC and ranged from 0.56 to 0.97 for MC. Inter-observer variability ranged from -30.5 ± 252.0 mm 3 to 84.0 ± 240.5 mm 3 for AVC and from -95.2 ± 210.0 mm 3 to 303.7 ± 501.6 mm 3 for MC. AVC can be quantified with excellent reliability on ungated unenhanced low-dose chest CT, but manual detection of MC can be subject to substantial inter-observer variability. Lung cancer screening CT may be used for detection and quantification of cardiac valve calcifications. (orig.)

  3. Cardiac valve calcifications on low-dose unenhanced ungated chest computed tomography: inter-observer and inter-examination reliability, agreement and variability

    Energy Technology Data Exchange (ETDEWEB)

    Hamersvelt, Robbert W. van; Willemink, Martin J.; Takx, Richard A.P.; Eikendal, Anouk L.M.; Budde, Ricardo P.J.; Leiner, Tim; Jong, Pim A. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Mol, Christian P.; Isgum, Ivana [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands)

    2014-07-15

    To determine inter-observer and inter-examination variability for aortic valve calcification (AVC) and mitral valve and annulus calcification (MC) in low-dose unenhanced ungated lung cancer screening chest computed tomography (CT). We included 578 lung cancer screening trial participants who were examined by CT twice within 3 months to follow indeterminate pulmonary nodules. On these CTs, AVC and MC were measured in cubic millimetres. One hundred CTs were examined by five observers to determine the inter-observer variability. Reliability was assessed by kappa statistics (κ) and intra-class correlation coefficients (ICCs). Variability was expressed as the mean difference ± standard deviation (SD). Inter-examination reliability was excellent for AVC (κ = 0.94, ICC = 0.96) and MC (κ = 0.95, ICC = 0.90). Inter-examination variability was 12.7 ± 118.2 mm{sup 3} for AVC and 31.5 ± 219.2 mm{sup 3} for MC. Inter-observer reliability ranged from κ = 0.68 to κ = 0.92 for AVC and from κ = 0.20 to κ = 0.66 for MC. Inter-observer ICC was 0.94 for AVC and ranged from 0.56 to 0.97 for MC. Inter-observer variability ranged from -30.5 ± 252.0 mm{sup 3} to 84.0 ± 240.5 mm{sup 3} for AVC and from -95.2 ± 210.0 mm{sup 3} to 303.7 ± 501.6 mm{sup 3} for MC. AVC can be quantified with excellent reliability on ungated unenhanced low-dose chest CT, but manual detection of MC can be subject to substantial inter-observer variability. Lung cancer screening CT may be used for detection and quantification of cardiac valve calcifications. (orig.)

  4. Inter-observer variability between radiologists reporting on cerebellopontine angle tumours on magnetic resonance imaging.

    Science.gov (United States)

    Teh, S R; Ranguis, S; Fagan, P

    2017-01-01

    Studies demonstrate the significance of intra- and inter-observer variability when measuring cerebellopontine angle tumours on magnetic resonance imaging, with measured differences as high as 2 mm. To determine intra- and inter-observer measurement variability of cerebellopontine angle tumours in a specialised institution. The magnetic resonance imaging maximal diameter of 12 randomly selected cerebellopontine angle tumours were independently measured by 4 neuroradiologists at a tertiary referral centre using a standard definition for maximal tumour diameter. Average deviation and intraclass correlation were subsequently calculated. Inter-observer difference averaged 0.33 ± 0.04 mm (range, 0.0-0.8 mm). Intra-observer measurements were more consistent than inter-observer measurements, with differences averaging 0.17 mm (95 per cent confidence interval = 0.27-0.06, p = 0.002). Inter-observer reliability was 0.99 (95 per cent confidence interval = 0.97-0.99), suggesting high reliability between the readings. The use of a standard definition for maximal tumour volume provided high reliability amongst radiologists' readings. To avoid oversizing tumours, it is recommended that conservative monitoring be conducted by the same institution with thin slice magnetic resonance imaging scans.

  5. Inter-annual variations in wave spectral characteristics at a location off the central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Nair, M.A.

    The inter-annual variations in wave spectrum are examined based on the wave data measured at 9 m water depth off the central west coast of India from 2009 to 2012 using a wave rider buoy. The temporal variation of the spectral energy density over a...

  6. Intraregional and inter-regional variability of herbicide sensitivity in common arable weed populations

    DEFF Research Database (Denmark)

    de Mol, Friederike; Gerowitt, Bärbel; Kaczmarek, Sylwia

    2015-01-01

    The question on intraregional versus inter-regional variability in herbicide sensitivity for weed populations is of major importance, both in extrapolation of model parameters and in herbicide zonal approval procedures. We hypothesised that inter-regional variability in herbicide sensitivity...... for field populations would be the same as intraregional variability for regions with similar climatic conditions. Seeds of field weed populations were collected in a Danish, German and Polish region. Herbicide sensitivity was tested in dose–response experiments in the glasshouse with flufenacet...... and iodosulfuron (Apera spica-venti), florasulam and tribenuron (Tripleurospermum inodorum), diflufenican, diflufenican + flurtamone and pendimethalin (Viola arvensis). ED50 values and variance components of the ED50 values were estimated to describe the influence of region, year and population. The regions...

  7. Longitudinal intra- and inter-individual variability in young swimmers' performance and determinant competition factors

    Directory of Open Access Journals (Sweden)

    Jorge Estrela Morais

    2014-09-01

    Full Text Available The main purpose of this study was to follow-up the intra- and inter-individual variability of young swimmers' performance and determinant factors over two competitive seasons. Thirty young swimmers (14 boys: 12.33±0.65 years-old; 16 girls: 11.15±0.55 years-old were followed-up throughout two consecutive seasons (seven evaluation moments. Performance (100m freestyle, anthropometric, kinematic, hydrodynamic and efficiency features were evaluated. A gender and skill-level effect was observed. Boys improved in a higher amount (% comparing to girls. Overall, swimmers in skill-level 2 (both genders presented a higher intra-individual variability. Performance and anthropometrics showed a significant inter-individual variability in most moments, but hydrodynamics, kinematics and efficiency did not. Within each skill-level hydrodynamics, kinematics and efficiency were the variables that showed a high inter-individual variability. As a gender and skill-level effect was noticed in an age-group of young swimmers, coaches and practitioners should put the focus in specific and customized training plans for each skill-level of swimmers.

  8. Inter-subject variability in human atrial action potential in sinus rhythm versus chronic atrial fibrillation.

    Science.gov (United States)

    Sánchez, Carlos; Bueno-Orovio, Alfonso; Wettwer, Erich; Loose, Simone; Simon, Jana; Ravens, Ursula; Pueyo, Esther; Rodriguez, Blanca

    2014-01-01

    Human atrial electrophysiology exhibits high inter-subject variability in both sinus rhythm (SR) and chronic atrial fibrillation (cAF) patients. Variability is however rarely investigated in experimental and theoretical electrophysiological studies, thus hampering the understanding of its underlying causes but also its implications in explaining differences in the response to disease and treatment. In our study, we aim at investigating the ability of populations of human atrial cell models to capture the inter-subject variability in action potential (AP) recorded in 363 patients both under SR and cAF conditions. Human AP recordings in atrial trabeculae (n = 469) from SR and cAF patients were used to calibrate populations of computational SR and cAF atrial AP models. Three populations of over 2000 sampled models were generated, based on three different human atrial AP models. Experimental calibration selected populations of AP models yielding AP with morphology and duration in range with experimental recordings. Populations using the three original models can mimic variability in experimental AP in both SR and cAF, with median conductance values in SR for most ionic currents deviating less than 30% from their original peak values. All cAF populations show similar variations in G(K1), G(Kur) and G(to), consistent with AF-related remodeling as reported in experiments. In all SR and cAF model populations, inter-subject variability in I(K1) and I(NaK) underlies variability in APD90, variability in I(Kur), I(CaL) and I(NaK) modulates variability in APD50 and combined variability in Ito and I(Kur) determines variability in APD20. The large variability in human atrial AP triangulation is mostly determined by I(K1) and either I(NaK) or I(NaCa) depending on the model. Experimentally-calibrated human atrial AP models populations mimic AP variability in SR and cAF patient recordings, and identify potential ionic determinants of inter-subject variability in human atrial AP

  9. Inter-subject variability in human atrial action potential in sinus rhythm versus chronic atrial fibrillation.

    Directory of Open Access Journals (Sweden)

    Carlos Sánchez

    Full Text Available Human atrial electrophysiology exhibits high inter-subject variability in both sinus rhythm (SR and chronic atrial fibrillation (cAF patients. Variability is however rarely investigated in experimental and theoretical electrophysiological studies, thus hampering the understanding of its underlying causes but also its implications in explaining differences in the response to disease and treatment. In our study, we aim at investigating the ability of populations of human atrial cell models to capture the inter-subject variability in action potential (AP recorded in 363 patients both under SR and cAF conditions.Human AP recordings in atrial trabeculae (n = 469 from SR and cAF patients were used to calibrate populations of computational SR and cAF atrial AP models. Three populations of over 2000 sampled models were generated, based on three different human atrial AP models. Experimental calibration selected populations of AP models yielding AP with morphology and duration in range with experimental recordings. Populations using the three original models can mimic variability in experimental AP in both SR and cAF, with median conductance values in SR for most ionic currents deviating less than 30% from their original peak values. All cAF populations show similar variations in G(K1, G(Kur and G(to, consistent with AF-related remodeling as reported in experiments. In all SR and cAF model populations, inter-subject variability in I(K1 and I(NaK underlies variability in APD90, variability in I(Kur, I(CaL and I(NaK modulates variability in APD50 and combined variability in Ito and I(Kur determines variability in APD20. The large variability in human atrial AP triangulation is mostly determined by I(K1 and either I(NaK or I(NaCa depending on the model.Experimentally-calibrated human atrial AP models populations mimic AP variability in SR and cAF patient recordings, and identify potential ionic determinants of inter-subject variability in human atrial AP

  10. Mn∕Ca intra- and inter-test variability in the benthic foraminifer Ammonia tepida

    Directory of Open Access Journals (Sweden)

    J. Petersen

    2018-01-01

    Full Text Available The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+ and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn∕Ca ratios may hold important information about short-term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn∕Ca intra- and inter-test variability in living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (the Netherlands in three different months of 2012. The deeper parts of this lake are characterized by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intra-test variability due to ontogenetic trends (i.e. size-related effects and/or other vital effects occurring during calcification in A. tepida (11–25 % relative SD, RSD is responsible for part of the observed variability in Mn∕Ca. Our present results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn∕Ca intra- and inter-test variability (average of 45 % RSD. Within single specimens, both increasing and decreasing trends in Mn∕Ca ratios with size are observed. Our results suggest that the variability in successive single-chamber Mn∕Ca ratios reflects the temporal variability in pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn

  11. Mn/Ca intra- and inter-test variability in the benthic foraminifer Ammonia tepida

    Science.gov (United States)

    Petersen, Jassin; Barras, Christine; Bézos, Antoine; La, Carole; de Nooijer, Lennart J.; Meysman, Filip J. R.; Mouret, Aurélia; Slomp, Caroline P.; Jorissen, Frans J.

    2018-01-01

    The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn/Ca ratios may hold important information about short-term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn/Ca intra- and inter-test variability in living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (the Netherlands) in three different months of 2012. The deeper parts of this lake are characterized by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intra-test variability due to ontogenetic trends (i.e. size-related effects) and/or other vital effects occurring during calcification in A. tepida (11-25 % relative SD, RSD) is responsible for part of the observed variability in Mn/Ca. Our present results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn/Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn/Ca ratios with size are observed. Our results suggest that the variability in successive single-chamber Mn/Ca ratios reflects the temporal variability in pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn/Ca variability.

  12. Spatial and temporal changes in inter-annual and seasonal NDVI in the Qinling mountains of China

    Science.gov (United States)

    Wang, Tao; Lu, Ying

    2017-11-01

    As an important ecological barrier in central China, the Qinling Mountains have received more attention in response to global or regional climate change. Spatial and temporal changes of inter-annual and seasonal NDVI were analysed after extraction of the vegetation growth season, based on MODIS NDVI images and linear trend analysis. The results showed that: (1) the NDVI value and vegetation cover level of the Qinling Mountains were high. The NDVI showed significant annual and seasonal increases, in which the summer value contributed the most to the inter-annual value, followed by spring and autumn. In terms of the change trend, the NDVI showed a linear increase in annual and seasonal data, in which the spring growth rate contributed the most to the inter-annual value, followed by autumn and summer. (2) The spatial distribution of the linear change trend of the NDVI in the inter-annual and seasonal data was mainly increased, but the area of reduction was also large. The area of reduced NDVI was mainly distributed in the middle and western area with middle and high elevations, as well as urban neighbourhoods with intensive human activities, such as the Hanzhong basin, the Ankang basin, and the Shangluo basin. The rate of change in NDVI in human activity areas was higher than in the middle and higher elevation areas. The change may be driven by human activities in the former and by climate change in the latter. Monitoring of the vegetation ecological system in the Qinling Mountains should be strengthened to understand the change process, as well as to provide a scientific basis when making policies for regional ecological environmental protection.

  13. Inter-annual variations of CO2 observed by commercial airliner in the CONTRAIL project

    Science.gov (United States)

    Sawa, Yousuke; Machida, Toshinobu; Matsueda, Hidekazu; Niwa, Yosuke; Umezawa, Taku

    2016-04-01

    Since 2005, we have conducted an observation program for greenhouse gases using the passenger aircraft of the Japan Airlines named Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL). Over the past 10 years, successful operation of Continuous CO2 Measuring Equipment (CME) has delivered more than 6 million in-situ CO2 data from about 12000 flights between Japan and Europe, Australia, North America, or Asia. The large number of CME data enable us to well characterize spatial distributions and seasonal changes of CO2 in wide regions of the globe especially the Asia-Pacific regions. While the mean growth rates for the past 10 years were about 2 ppm/year, large growth rates of about 3 ppm/year were found in the wide latitudinal bands from 30S to 70N from the second half of 2012 to the first half of 2013. The multiyear data sets have the potential to help understand the global/regional CO2 budget. One good example is the significant inter-annual difference in CO2 vertical profiles observed over Singapore between October 2014 and October 2015, which is attributable to the massive biomass burnings in Indonesia in 2015.

  14. Mechanisms influencing seasonal to inter-annual prediction skill of sea ice extent in the Arctic Ocean in MIROC

    Science.gov (United States)

    Ono, Jun; Tatebe, Hiroaki; Komuro, Yoshiki; Nodzu, Masato I.; Ishii, Masayoshi

    2018-02-01

    To assess the skill of seasonal to inter-annual predictions of the detrended sea ice extent in the Arctic Ocean (SIEAO) and to clarify the underlying physical processes, we conducted ensemble hindcasts, started on 1 January, 1 April, 1 July and 1 October for each year from 1980 to 2011, for lead times up to three years, using the Model for Interdisciplinary Research on Climate (MIROC) version 5 initialised with the observed atmosphere and ocean anomalies and sea ice concentration. Significant skill is found for the winter months: the December SIEAO can be predicted up to 11 months ahead (anomaly correlation coefficient is 0.42). This skill might be attributed to the subsurface ocean heat content originating in the North Atlantic. A plausible mechanism is as follows: the subsurface water flows into the Barents Sea from spring to fall and emerges at the surface in winter by vertical mixing, and eventually affects the sea ice variability there. Meanwhile, the September SIEAO predictions are skillful for lead times of up to two months, due to the persistence of sea ice in the Beaufort, Chukchi, and East Siberian seas initialised in July, as suggested by previous studies.

  15. Inter-individual cognitive variability in children with Asperger’s syndrome

    Directory of Open Access Journals (Sweden)

    Maria Luz Gonzalez-Gadea

    2014-07-01

    Full Text Available Multiple studies have tried to establish the distinctive profile of individuals with Asperger’s syndrome (AS. However, recent reports suggest that adults with AS feature heterogeneous cognitive profiles. The present study explores inter-individual variability in children with AS through group comparison and multiple case series analysis. All participants completed an extended battery including measures of fluid and crystallized intelligence, executive functions, theory of mind, and classical neuropsychological tests. Significant group differences were found in theory of mind and other domains related to global information processing. However, the AS group showed high inter-individual variability (both sub- and supra-normal performance on most cognitive tasks. Furthermore, high fluid intelligence correlated with less general cognitive impairment, high cognitive flexibility, and speed motor processing. In light of these findings, we propose that children with AS are characterized by a distinct, uneven pattern of cognitive strengths and weaknesses.

  16. Evaluation of Accelerometer Inter-Device Variability and Collar Placement in Dogs

    Directory of Open Access Journals (Sweden)

    Anastasia M. Olsen

    2016-05-01

    Full Text Available Objective: To compare accelerometer inter-device variability and to evaluate the effect of canine collar tightness on activity counts.Evidentiary value: This is a prospective study of six dogs wearing Actical accelerometers over 24 hours with variable placement to evaluate accelerometer inter-device variability and collar tightness. Methods: Six skeletally mature medium to large breed client-owned dogs were enrolled in the study. Twelve identical accelerometer devices were used, with the same two devices used for each dog. All accelerometers were placed on the ventral cervical region. A total of four placement patterns (P1: two accelerometers on the same collar; P2: two separate collars with same tightness with one accelerometer on each collar; P3 & P4: one collar loose/one collar tight and one accelerometer on each collar were evaluated. Pearson’s correlation, paired t-tests, and percent of variation between total activity counts for each placement period were calculated.Results: For P1-P4, Pearson’s correlation was 0.92, 0.95, 0.93, and 0.86 (p<0.0001 for all comparisons. For P1-P4, t-ratio was -20.59 (p<0.0001, 9.78 (p<0.0001, -8.95 (p<0.0001, and -2.15 (p<0.0313, respectively. When evaluating inter-device variability, the percent differences between total activity counts of device pairs ranged from 2.5 to 56.8%. Conclusion: While the correlations between devices for all placements were high, the high inter-device variability shows that further investigation is necessary. From this study, the results suggest that changing devices throughout a study should be avoided. We recommend that attachment of the accelerometers to the collar, including collar tightness, should be kept consistent until further studies are available. Application: When accelerometer data are used for objective outcomes, accelerometer inter-device variability and collar tightness should be taken into account.

  17. Variations of Histone Modification Patterns: Contributions of Inter-plant Variability and Technical Factors

    Directory of Open Access Journals (Sweden)

    Sylva Brabencová

    2017-12-01

    Full Text Available Inter-individual variability of conspecific plants is governed by differences in their genetically determined growth and development traits, environmental conditions, and adaptive responses under epigenetic control involving histone post-translational modifications. The apparent variability in histone modifications among plants might be increased by technical variation introduced in sample processing during epigenetic analyses. Thus, to detect true variations in epigenetic histone patterns associated with given factors, the basal variability among samples that is not associated with them must be estimated. To improve knowledge of relative contribution of biological and technical variation, mass spectrometry was used to examine histone modification patterns (acetylation and methylation among Arabidopsis thaliana plants of ecotypes Columbia 0 (Col-0 and Wassilewskija (Ws homogenized by two techniques (grinding in a cryomill or with a mortar and pestle. We found little difference in histone modification profiles between the ecotypes. However, in comparison of the biological and technical components of variability, we found consistently higher inter-individual variability in histone mark levels among Ws plants than among Col-0 plants (grown from seeds collected either from single plants or sets of plants. Thus, more replicates of Ws would be needed for rigorous analysis of epigenetic marks. Regarding technical variability, the cryomill introduced detectably more heterogeneity in the data than the mortar and pestle treatment, but mass spectrometric analyses had minor apparent effects. Our study shows that it is essential to consider inter-sample variance and estimate suitable numbers of biological replicates for statistical analysis for each studied organism when investigating changes in epigenetic histone profiles.

  18. Variations of Histone Modification Patterns: Contributions of Inter-plant Variability and Technical Factors.

    Science.gov (United States)

    Brabencová, Sylva; Ihnatová, Ivana; Potěšil, David; Fojtová, Miloslava; Fajkus, Jiří; Zdráhal, Zbyněk; Lochmanová, Gabriela

    2017-01-01

    Inter-individual variability of conspecific plants is governed by differences in their genetically determined growth and development traits, environmental conditions, and adaptive responses under epigenetic control involving histone post-translational modifications. The apparent variability in histone modifications among plants might be increased by technical variation introduced in sample processing during epigenetic analyses. Thus, to detect true variations in epigenetic histone patterns associated with given factors, the basal variability among samples that is not associated with them must be estimated. To improve knowledge of relative contribution of biological and technical variation, mass spectrometry was used to examine histone modification patterns (acetylation and methylation) among Arabidopsis thaliana plants of ecotypes Columbia 0 (Col-0) and Wassilewskija (Ws) homogenized by two techniques (grinding in a cryomill or with a mortar and pestle). We found little difference in histone modification profiles between the ecotypes. However, in comparison of the biological and technical components of variability, we found consistently higher inter-individual variability in histone mark levels among Ws plants than among Col-0 plants (grown from seeds collected either from single plants or sets of plants). Thus, more replicates of Ws would be needed for rigorous analysis of epigenetic marks. Regarding technical variability, the cryomill introduced detectably more heterogeneity in the data than the mortar and pestle treatment, but mass spectrometric analyses had minor apparent effects. Our study shows that it is essential to consider inter-sample variance and estimate suitable numbers of biological replicates for statistical analysis for each studied organism when investigating changes in epigenetic histone profiles.

  19. Inter-annual variations in water yield to lakes in northeastern Alberta: implications for estimating critical loads of acidity

    Directory of Open Access Journals (Sweden)

    Roderick HAZEWINKEL

    2010-08-01

    Full Text Available Stable isotopes of water were applied to estimate water yield to fifty lakes in northeastern Alberta as part of an acid sensitivity study underway since 2002 in the Athabasca Oil Sands Region (AOSR. Herein, we apply site-specific water yields for each lake to calculate critical loads of acidity using water chemistry data and a steady-state water chemistry model. The main goal of this research was to improve site-specific critical load estimates and to understand the sensitivity to hydrologic variability across a Boreal Plains region under significant oil sands development pressure. Overall, catchment water yields were found to vary significantly over the seven year monitoring period, with distinct variations among lakes and between different regions, overprinted by inter-annual climate-driven shifts. Analysis of critical load estimates based on site-specific water yields suggests that caution must be applied to establish hydrologic conditions and define extremes at specific sites in order to protect more sensitive ecosystems. In general, lakes with low (high water yield tended to be more (less acid sensitive but were typically less (more affected by interannual hydrological variations. While it has been customary to use long-term water yields to define a static critical load for lakes, we find that spatial and temporal variability in water yield may limit effectiveness of this type of assessment in areas of the Boreal Plain characterized by heterogeneous runoff and without a long-term lake-gauging network. Implications for predicting acidification risk are discussed for the AOSR.

  20. A procedure to derive intra-and inter-annual changes on vegetation from NDVI time series. A case study in Spain

    International Nuclear Information System (INIS)

    Gilabert, M. A; Martinez, B.; Melia, J.

    2009-01-01

    The objective of this work is to study the spatial patterns of vegetation activity over spain and its temporal variability throughout the period 1989-2002. A multi-resolution analysis (MRA) bases on the wavelet transform has been implemented on NDVI time series from the MEDOKADS database. The MRA decomposes the original signal as a sum of series associated with temporal scales. Specifically, the intra-annual series is processed to define several key features in relation with the vegetation penology. In contras, the inter-annual components of the signal is used to detect trends by means of a Mann-Kendall test and map the magnitude of the land-cover change. Finally, a comprehensive identification of the areas presenting a negative value of the magnitude of change is carried out to select those linked to land degradation processes. Results show a major presence of these areas the Southeast of Spain. (Author) 5 refs.

  1. Approaches for modeling within subject variability in pharmacometric count data analysis: dynamic inter-occasion variability and stochastic differential equations.

    Science.gov (United States)

    Deng, Chenhui; Plan, Elodie L; Karlsson, Mats O

    2016-06-01

    Parameter variation in pharmacometric analysis studies can be characterized as within subject parameter variability (WSV) in pharmacometric models. WSV has previously been successfully modeled using inter-occasion variability (IOV), but also stochastic differential equations (SDEs). In this study, two approaches, dynamic inter-occasion variability (dIOV) and adapted stochastic differential equations, were proposed to investigate WSV in pharmacometric count data analysis. These approaches were applied to published count models for seizure counts and Likert pain scores. Both approaches improved the model fits significantly. In addition, stochastic simulation and estimation were used to explore further the capability of the two approaches to diagnose and improve models where existing WSV is not recognized. The results of simulations confirmed the gain in introducing WSV as dIOV and SDEs when parameters vary randomly over time. Further, the approaches were also informative as diagnostics of model misspecification, when parameters changed systematically over time but this was not recognized in the structural model. The proposed approaches in this study offer strategies to characterize WSV and are not restricted to count data.

  2. Particle size distribution function of photoelectric counter and closed volume aureole photometer (seasonal variations and inter-annual differences)

    Science.gov (United States)

    Polkin, Vas. V.; Polkin, Vik. V.; Panchenko, M. V.

    2017-11-01

    The results of atmospheric aerosol monitoring are discussed. We compare data of particle size distribution function, which are obtained by photoelectric counter, with inversion of data closed volume aureole photometer, that's allow us to measure the aureole scattering phase function in the range of angles 1.2-20 degrees at a wavelength of 650 nm. Seasonal variations and inter-annual differences collected from 2010 to 2015 years are analyzed and evaluated.

  3. Definition of gross tumor volume in lung cancer: inter-observer variability

    International Nuclear Information System (INIS)

    Van de Steene, Jan; Linthout, Nadine; Mey, Johan de; Vinh-Hung, Vincent; Claassens, Cornelia; Noppen, Marc; Bel, Arjan; Storme, Guy

    2002-01-01

    Background and purpose: To determine the inter-observer variation in gross tumor volume (GTV) definition in lung cancer, and its clinical relevance. Material and methods: Five clinicians involved in lung cancer were asked to define GTV on the planning CT scan of eight patients. Resulting GTVs were compared on the base of geometric volume, dimensions and extensions. Judgement of invasion of lymph node (LN) regions was evaluated using the ATS/LCSG classification of LN. Clinical relevance of the variation was studied through 3D-dosimetry of standard conformal plans: volume of critical organs (heart, lungs, esophagus, spinal cord) irradiated at toxic doses, 95% isodose volumes of GTVs, normal tissue complication probabilities (NTCP) and tumor control probabilities (TCP) were compared for evaluation of observer variability. Results: Before evaluation of observer variability, critical review of planning CT scan led to up- (two cases) and downstaging (one case) of patients as compared to the respective diagnostic scans. The defined GTVs showed an inter-observer variation with a ratio up to more than 7 between maximum and minimum geometric content. The dimensions of the primary tumor had inter-observer ranges of 4.2 (transversal), 7.9 (cranio-caudal) and 5.4 (antero-posterior) cm. Extreme extensions of the GTVs (left, right, cranial, caudal, anterior and posterior) varied with ranges of 2.8-7.3 cm due to inter-observer variation. After common review, only 63% of involved lymph node regions were delineated by the clinicians (i.e. 37% are false negative). Twenty-two percent of drawn in lymph node regions were accepted to be false positive after review. In the conformal plans, inter-observer ranges of irradiated normal tissue volume were on average 12%, with a maximum of 66%. The probability (in the population of all conformal plans) of irradiating at least 95% of the GTV with at least 95% of the nominal treatment dose decreased from 96 to 88% when swapping the matched GTV

  4. Magnetic resonance imaging for prostate bed radiotherapy planning: An inter- and intra-observer variability study

    International Nuclear Information System (INIS)

    Barkati, Maroie; Simard, Dany; Taussky, Daniel; Delouya, Guiula

    2016-01-01

    We assessed the inter- and intra-observer variability in contouring the prostate bed for radiation therapy planning using MRI compared with computed tomography (CT). We selected 15 patients with prior radical prostatectomy. All had CT and MRI simulation for planning purposes. Image fusions were done between CT and MRI. Three radiation oncologists with several years of experience in treating prostate cancer contoured the prostate bed first on CT and then on MRI. Before contouring, each radiation oncologist had to review the Radiation Therapy Oncology Group guidelines for postoperative external beam radiotherapy. The agreement between volumes was calculated using the Dice similarity coefficient (DSC). Analysis was done using the Matlab software. The DSC was compared using non-parametric statistical tests. Contouring on CT alone showed a statistically significant (P = 0.001) higher similarity between observers with a mean DSC of 0.76 (standard deviation ± 0.05) compared with contouring on MRI with a mean of 0.66 (standard deviation ± 0.05). Mean intra-observer variability between CT and MRI was 0.68, 0.75 and 0.78 for the three observers. The clinical target volume was 19 - 74% larger on CT than on MRI. The intra-observer difference in clinical target volume between CT and MRI was statistically significant in two observers and non-significant in the third one (P = 0.09). We found less inter-observer variability when contouring on CT than on MRI. Radiation Therapy Oncology Group contouring guidelines are based on anatomical landmarks readily visible on CT. These landmarks are more inter-observer dependent on MRI. Therefore, present contouring guidelines might not be applicable to MRI planning.

  5. The influence of inter-annually varying albedo on regional climate and drought

    KAUST Repository

    Meng, Xianhong

    2013-05-05

    strengthening of the second mechanism. That is, the second mechanism is stronger in a drought year compared to a normal year and this difference is larger than for the first mechanism. When both mechanisms are active, the second mechanism tends to dominate across the model domain, particularly during the 2002 drought period. The introduction of observed inter-annual variations in albedo produces an enhancement of the first mechanism and a weakening of the second mechanism during the onset of the drought. © 2013 Springer-Verlag Berlin Heidelberg.

  6. Inter-Individual Variability in Human Response to Low-Dose Ionizing Radiation, Final Report

    International Nuclear Information System (INIS)

    Rocke, David

    2016-01-01

    In order to investigate inter-individual variability in response to low-dose ionizing radiation, we are working with three models, 1) in-vivo irradiated human skin, for which we have a realistic model, but with few subjects, all from a previous project, 2) ex-vivo irradiated human skin, for which we also have a realistic model, though with the limitations involved in keeping skin pieces alive in media, and 3) MatTek EpiDermFT skin plugs, which provides a more realistic model than cell lines, which is more controllable than human samples.

  7. Inter-operator Variability in Defining Uterine Position Using Three-dimensional Ultrasound Imaging

    DEFF Research Database (Denmark)

    Baker, Mariwan; Jensen, Jørgen Arendt; Behrens, Claus F.

    2013-01-01

    to displacement by applied operator-pressure that mimics an actual GYN patient. The transabdominal scanning was performed using a 3D-US system (Clarity® Model 310C00, Elekta, Montreal, Canada). It consists of a US acquisition-station, workstation, and a 128- element 1D array curved probe. The iterated US......-scans were performed in four subsequent sessions (totally 21 US-scans) in a period of four weeks to investigate the randomness of the inter-operator variability. An additionally US-scan was performed as a reference target volume to the consecutive scans. At first, the phantom was marked with ball bearings...

  8. Inter-Individual Variability in Human Response to Low-Dose Ionizing Radiation, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rocke, David [Univ. of California, Davis, CA (United States)

    2016-08-01

    In order to investigate inter-individual variability in response to low-dose ionizing radiation, we are working with three models, 1) in-vivo irradiated human skin, for which we have a realistic model, but with few subjects, all from a previous project, 2) ex-vivo irradiated human skin, for which we also have a realistic model, though with the limitations involved in keeping skin pieces alive in media, and 3) MatTek EpiDermFT skin plugs, which provides a more realistic model than cell lines, which is more controllable than human samples.

  9. Clinical impact of prostate specific antigen (PSA) inter-assay variability on management of prostate cancer.

    Science.gov (United States)

    Murthy, Vedang; Rishi, Anupam; Gupta, Sanjeev; Kannan, Sadhana; Mahantshetty, Umesh; Tongaonkar, Hemant; Bakshi, Ganesh; Prabhash, Kumar; Bhanushali, Paresh; Shinde, Bhoopal; Inamdar, Nitin; Shrivastava, Shyamkishore

    2016-01-01

    To evaluate the inter-assay variability of six commercially available prostate specific antigen (PSA) assays, its clinical impact in prostate cancer (PCa) and comparison of automated versus manual assays. Sera from 495 patients (425 with PCa and 70 men with Benign Prostatic Hyperplasia (BPH), were measured with six different assays [three automated assays (a-PSA) and three manual ELISA based assay (m-PSA)]. Variability, agreement and bias were measured and compared among assays using Bland Altman plots and Passing and Bablok regression analysis. The possible impact of inter-assay variability on important clinical scenarios was also studied. All the assays were well correlated (r: 0.88-0.98); however there was significant disagreement and bias between the systems, which were more pronounced among the a-PSA assays. The Bland Altman plot showed that the variability was high between the m-PSA assays and the standard Abbott system with mean difference of 3.8-5.8ng/ml. In contrast, the a-PSA had better agreement with mean difference of 0.8-2.3ng/ml. Beckman Coulter showed the best agreement to the institutional reference (slope-1.097; 95% CI: 1.06-1.14; p<0.05, and intercept-0.20; 95% CI-0.38-0.58; p<0.05, Passing Bablok). It led to significant variability in PCa risk stratification and failure to detect biochemical failure in more than 50% cases. The discrepancies between the assays lead to significant clinical misinterpretation with risk group migration and detection of biochemical failure post radiotherapy. There are significant discordances between automated and ELISA based assays. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  10. 3D facial landmarks: Inter-operator variability of manual annotation

    DEFF Research Database (Denmark)

    Fagertun, Jens; Harder, Stine; Rosengren, Anders

    2014-01-01

    in regards to intra-operator and portraits. Using a sparse set of landmarks (n=14), that capture the whole face, the dense point mean variance was reduced from 1.92 to 0.54 mm. Conclusion The inter-operator variability was primarily associated with particular landmarks, where more leniently landmarks had......Background Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.......g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance. Method Facial scans from 36 voluntary unrelated blood donors from the Danish Blood Donor Study...

  11. Measurement of transplanted pancreatic volume using computed tomography: reliability by intra- and inter-observer variability

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, Eva; Segelsjoe, Monica; Magnusson, Anders [Uppsala Univ., Dept. of Radiology, Oncology and Radiation Science, Section of Radiology, Uppsala (Sweden)], E-mail: eva.lundqvist.8954@student.uu.se; Andersson, Anna; Biglarnia, Ali-Reza [Dept. of Surgical Sciences, Section of Transplantation Surgery, Uppsala Univ. Hospital, Uppsala (Sweden)

    2012-11-15

    Background Unlike other solid organ transplants, pancreas allografts can undergo a substantial decrease in baseline volume after transplantation. This phenomenon has not been well characterized, as there are insufficient data on reliable and reproducible volume assessments. We hypothesized that characterization of pancreatic volume by means of computed tomography (CT) could be a useful method for clinical follow-up in pancreas transplant patients. Purpose To evaluate the feasibility and reliability of pancreatic volume assessment using CT scan in transplanted patients. Material and Methods CT examinations were performed on 21 consecutive patients undergoing pancreas transplantation. Volume measurements were carried out by two observers tracing the pancreatic contours in all slices. The observers performed the measurements twice for each patient. Differences in volume measurement were used to evaluate intra- and inter-observer variability. Results The intra-observer variability for the pancreatic volume measurements of Observers 1 and 2 was found to be in almost perfect agreement, with an intraclass correlation coefficient (ICC) of 0.90 (0.77-0.96) and 0.99 (0.98-1.0), respectively. Regarding inter-observer validity, the ICCs for the first and second measurements were 0.90 (range, 0.77-0.96) and 0.95 (range, 0.85-0.98), respectively. Conclusion CT volumetry is a reliable and reproducible method for measurement of transplanted pancreatic volume.

  12. Thyroid Ultrasound: Change of Inter-observer Variability and Diagnostic Performance after Training

    International Nuclear Information System (INIS)

    Moon, Hee Jung; Kim, Eun Kyung; Kwak, Jin Young; Park, Jeong Seon

    2011-01-01

    To investigate and compare inter-observer variability and diagnostic performance of thyroid ultrasound (US) between a faculty member and observing residents. From October 2007 to June 2009, 18 residents underwent training in thyroid US section. Group 1 included 8 residents that were trained for the first time and group 2 included 10 residents that were trained for the second time. US features of nodules were recorded according to the composition, echogenicity, margin, calcifications, shape, and final assessment by a faculty member and residents, respectively. Following a discussion, a faculty member performed fine needle aspiration. Then, the inter-observer variability and diagnostic performance between a faculty member and residents were investigated and compared for US. In group 1, agreement for composition in resident 1, calcification for residents 5 and 6, and shape for resident 4 were slight, moderate, moderate, and moderate, respectively. In group 2, agreement for composition in residents 1 and 10 were moderate. Substantial or greater agreement was observed more frequently in group 2 than 1. The diagnostic performances for both the faculty and residents were high and not statistically different. Agreement for US features between a faculty and residents as well as diagnostic performance were high. Moreover, diagnostic performance of residents that underwent training a second time of training was higher than residents that underwent training only once

  13. Measurement of transplanted pancreatic volume using computed tomography: reliability by intra- and inter-observer variability

    International Nuclear Information System (INIS)

    Lundqvist, Eva; Segelsjoe, Monica; Magnusson, Anders; Andersson, Anna; Biglarnia, Ali-Reza

    2012-01-01

    Background Unlike other solid organ transplants, pancreas allografts can undergo a substantial decrease in baseline volume after transplantation. This phenomenon has not been well characterized, as there are insufficient data on reliable and reproducible volume assessments. We hypothesized that characterization of pancreatic volume by means of computed tomography (CT) could be a useful method for clinical follow-up in pancreas transplant patients. Purpose To evaluate the feasibility and reliability of pancreatic volume assessment using CT scan in transplanted patients. Material and Methods CT examinations were performed on 21 consecutive patients undergoing pancreas transplantation. Volume measurements were carried out by two observers tracing the pancreatic contours in all slices. The observers performed the measurements twice for each patient. Differences in volume measurement were used to evaluate intra- and inter-observer variability. Results The intra-observer variability for the pancreatic volume measurements of Observers 1 and 2 was found to be in almost perfect agreement, with an intraclass correlation coefficient (ICC) of 0.90 (0.77-0.96) and 0.99 (0.98-1.0), respectively. Regarding inter-observer validity, the ICCs for the first and second measurements were 0.90 (range, 0.77-0.96) and 0.95 (range, 0.85-0.98), respectively. Conclusion CT volumetry is a reliable and reproducible method for measurement of transplanted pancreatic volume

  14. Inter-observer variability within BI-RADS and RANZCR mammographic density assessment schemes

    Science.gov (United States)

    Damases, Christine N.; Mello-Thoms, Claudia; McEntee, Mark F.

    2016-03-01

    This study compares variability associated with two visual mammographic density (MD) assessment methods using two separate samples of radiologists. The image test-set comprised of images obtained from 20 women (age 42-89 years). The images were assessed for their MD by twenty American Board of Radiology (ABR) examiners and twenty-six radiologists registered with the Royal Australian and New Zealand College of Radiologists (RANZCR). Images were assessed using the same technology and conditions, however the ABR radiologists used the BI-RADS and the RANZCR radiologists used the RANZCR breast density synoptic. Both scales use a 4-point assessment. The images were then grouped as low- and high-density; low including BIRADS 1 and 2 or RANZCR 1 and 2 and high including BI-RADS 3 and 4 or RANZCR 3 and 4. Four-point BI-RADS and RANZCR showed no or negligible correlation (ρ=-0.029 pBI-RADS scale had a Kappa of 0.565; [95% CI = 0.519 - 0.610], and ranged between 0.328-0.669 while the inter-observer agreement using the RANZCR scale had a Kappa of 0.360; [95% CI = 0.308 - 0.412] and a range of 0.078-0.499. Our findings show a wider range of inter-observer variability among RANZCR registered radiologists than the ABR examiners.

  15. Perception of ELF electromagnetic fields: excitation thresholds and inter-individual variability.

    Science.gov (United States)

    Leitgeb, N; Schröttner, J; Cech, R

    2007-06-01

    So far, in guidelines limiting exposure to electromagnetic fields, basic limits of intracorporal electric current densities have been recommended to prevent from nerve cell stimulation. They were based on experimental data and extrapolated to the general population with limited knowledge on the inter-individual variability. To assess the variability of cellular excitability the perception thresholds for directly applied electric currents were used as surrogate. However, until recently, the data on perception ability of electric currents were gained from small groups only and led to controversial results, differing by more than one order of magnitude. This paper discusses the results of our previous research comprising extensive measurements on 1,071 individuals (349 men and 359 women aging 16 to 60 y, 117 girls and 123 boys aging 9 to 16 years, and 123 individuals older than 60 y). Their electric current perception thresholds fit fairly well with a log-normal distribution. The electric 50 Hz current perception threshold was measured by directly applied pairs of electrodes at the lower forearms. It was found that the inter-individual variability comprises two orders of magnitudes which is one order of magnitude higher than assumed so far. Women were found to be significantly more sensitive than men. Depending on the level of probability p, the perception threshold for women was 0.77-fold (p = 50%) or even 0.45-fold (p = 0.5%) lower than for men. Surprisingly, children turned out to be considerably more sensitive than men but similar to women. The age dependence exhibited a decrease of perception thresholds with age from adult men to boys joining the values of girls at ages around 10 y. The results indicate that existing safety limits for touch currents need critical review. Apart from the inter-individual variability, it was estimated to which place within the distribution of perception levels the basic limits were related. Therefore, numerical simulations were made

  16. Quantifying inter-laboratory variability in stable isotope analysis of ancient skeletal remains.

    Science.gov (United States)

    Pestle, William J; Crowley, Brooke E; Weirauch, Matthew T

    2014-01-01

    Over the past forty years, stable isotope analysis of bone (and tooth) collagen and hydroxyapatite has become a mainstay of archaeological and paleoanthropological reconstructions of paleodiet and paleoenvironment. Despite this method's frequent use across anthropological subdisciplines (and beyond), the present work represents the first attempt at gauging the effects of inter-laboratory variability engendered by differences in a) sample preparation, and b) analysis (instrumentation, working standards, and data calibration). Replicate analyses of a 14C-dated ancient human bone by twenty-one archaeological and paleoecological stable isotope laboratories revealed significant inter-laboratory isotopic variation for both collagen and carbonate. For bone collagen, we found a sizeable range of 1.8‰ for δ13Ccol and 1.9‰ for δ15Ncol among laboratories, but an interpretatively insignificant average pairwise difference of 0.2‰ and 0.4‰ for δ13Ccol and δ15Ncol respectively. For bone hydroxyapatite the observed range increased to a troublingly large 3.5‰ for δ13Cap and 6.7‰ for δ18Oap, with average pairwise differences of 0.6‰ for δ13Cap and a disquieting 2.0‰ for δ18Oap. In order to assess the effects of preparation versus analysis on isotopic variability among laboratories, a subset of the samples prepared by the participating laboratories were analyzed a second time on the same instrument. Based on this duplicate analysis, it was determined that roughly half of the isotopic variability among laboratories could be attributed to differences in sample preparation, with the other half resulting from differences in analysis (instrumentation, working standards, and data calibration). These findings have serious implications for choices made in the preparation and extraction of target biomolecules, the comparison of results obtained from different laboratories, and the interpretation of small differences in bone collagen and hydroxyapatite isotope values

  17. Quantifying inter-laboratory variability in stable isotope analysis of ancient skeletal remains.

    Directory of Open Access Journals (Sweden)

    William J Pestle

    Full Text Available Over the past forty years, stable isotope analysis of bone (and tooth collagen and hydroxyapatite has become a mainstay of archaeological and paleoanthropological reconstructions of paleodiet and paleoenvironment. Despite this method's frequent use across anthropological subdisciplines (and beyond, the present work represents the first attempt at gauging the effects of inter-laboratory variability engendered by differences in a sample preparation, and b analysis (instrumentation, working standards, and data calibration. Replicate analyses of a 14C-dated ancient human bone by twenty-one archaeological and paleoecological stable isotope laboratories revealed significant inter-laboratory isotopic variation for both collagen and carbonate. For bone collagen, we found a sizeable range of 1.8‰ for δ13Ccol and 1.9‰ for δ15Ncol among laboratories, but an interpretatively insignificant average pairwise difference of 0.2‰ and 0.4‰ for δ13Ccol and δ15Ncol respectively. For bone hydroxyapatite the observed range increased to a troublingly large 3.5‰ for δ13Cap and 6.7‰ for δ18Oap, with average pairwise differences of 0.6‰ for δ13Cap and a disquieting 2.0‰ for δ18Oap. In order to assess the effects of preparation versus analysis on isotopic variability among laboratories, a subset of the samples prepared by the participating laboratories were analyzed a second time on the same instrument. Based on this duplicate analysis, it was determined that roughly half of the isotopic variability among laboratories could be attributed to differences in sample preparation, with the other half resulting from differences in analysis (instrumentation, working standards, and data calibration. These findings have serious implications for choices made in the preparation and extraction of target biomolecules, the comparison of results obtained from different laboratories, and the interpretation of small differences in bone collagen and hydroxyapatite

  18. Characterizing Tropical Tree Species Growth Strategies: Learning from Inter-Individual Variability and Scale Invariance

    Science.gov (United States)

    Le Bec, Jimmy; Courbaud, Benoit; Le Moguédec, Gilles; Pélissier, Raphaël

    2015-01-01

    Understanding how tropical tree species differ in their growth strategies is critical to predict forest dynamics and assess species coexistence. Although tree growth is highly variable in tropical forests, species maximum growth is often considered as a major axis synthesizing species strategies, with fast-growing pioneer and slow-growing shade tolerant species as emblematic representatives. We used a hierarchical linear mixed model and 21-years long tree diameter increment series in a monsoon forest of the Western Ghats, India, to characterize species growth strategies and question whether maximum growth summarizes these strategies. We quantified both species responses to biotic and abiotic factors and individual tree effects unexplained by these factors. Growth responses to competition and tree size appeared highly variable among species which led to reversals in performance ranking along those two gradients. However, species-specific responses largely overlapped due to large unexplained variability resulting mostly from inter-individual growth differences consistent over time. On average one-third of the variability captured by our model was explained by covariates. This emphasizes the high dimensionality of the tree growth process, i.e. the fact that trees differ in many dimensions (genetics, life history) influencing their growth response to environmental gradients, some being unmeasured or unmeasurable. In addition, intraspecific variability increased as a power function of species maximum growth partly as a result of higher absolute responses of fast-growing species to competition and tree size. However, covariates explained on average the same proportion of intraspecific variability for slow- and fast-growing species, which showed the same range of relative responses to competition and tree size. These results reflect a scale invariance of the growth process, underlining that slow- and fast-growing species exhibit the same range of growth strategies. PMID

  19. Characterizing tropical tree species growth strategies: learning from inter-individual variability and scale invariance.

    Directory of Open Access Journals (Sweden)

    Jimmy Le Bec

    Full Text Available Understanding how tropical tree species differ in their growth strategies is critical to predict forest dynamics and assess species coexistence. Although tree growth is highly variable in tropical forests, species maximum growth is often considered as a major axis synthesizing species strategies, with fast-growing pioneer and slow-growing shade tolerant species as emblematic representatives. We used a hierarchical linear mixed model and 21-years long tree diameter increment series in a monsoon forest of the Western Ghats, India, to characterize species growth strategies and question whether maximum growth summarizes these strategies. We quantified both species responses to biotic and abiotic factors and individual tree effects unexplained by these factors. Growth responses to competition and tree size appeared highly variable among species which led to reversals in performance ranking along those two gradients. However, species-specific responses largely overlapped due to large unexplained variability resulting mostly from inter-individual growth differences consistent over time. On average one-third of the variability captured by our model was explained by covariates. This emphasizes the high dimensionality of the tree growth process, i.e. the fact that trees differ in many dimensions (genetics, life history influencing their growth response to environmental gradients, some being unmeasured or unmeasurable. In addition, intraspecific variability increased as a power function of species maximum growth partly as a result of higher absolute responses of fast-growing species to competition and tree size. However, covariates explained on average the same proportion of intraspecific variability for slow- and fast-growing species, which showed the same range of relative responses to competition and tree size. These results reflect a scale invariance of the growth process, underlining that slow- and fast-growing species exhibit the same range of growth

  20. Modelling Inter-relationships among water, governance, human development variables in developing countries with Bayesian networks.

    Science.gov (United States)

    Dondeynaz, C.; Lopez-Puga, J.; Carmona-Moreno, C.

    2012-04-01

    Improving Water and Sanitation Services (WSS), being a complex and interdisciplinary issue, passes through collaboration and coordination of different sectors (environment, health, economic activities, governance, and international cooperation). This inter-dependency has been recognised with the adoption of the "Integrated Water Resources Management" principles that push for the integration of these various dimensions involved in WSS delivery to ensure an efficient and sustainable management. The understanding of these interrelations appears as crucial for decision makers in the water sector in particular in developing countries where WSS still represent an important leverage for livelihood improvement. In this framework, the Joint Research Centre of the European Commission has developed a coherent database (WatSan4Dev database) containing 29 indicators from environmental, socio-economic, governance and financial aid flows data focusing on developing countries (Celine et al, 2011 under publication). The aim of this work is to model the WatSan4Dev dataset using probabilistic models to identify the key variables influencing or being influenced by the water supply and sanitation access levels. Bayesian Network Models are suitable to map the conditional dependencies between variables and also allows ordering variables by level of influence on the dependent variable. Separated models have been built for water supply and for sanitation because of different behaviour. The models are validated if complying with statistical criteria but either with scientific knowledge and literature. A two steps approach has been adopted to build the structure of the model; Bayesian network is first built for each thematic cluster of variables (e.g governance, agricultural pressure, or human development) keeping a detailed level for interpretation later one. A global model is then built based on significant indicators of each cluster being previously modelled. The structure of the

  1. Inter-annual variation of carbon uptake by a plantation oak woodland in south-eastern England

    Directory of Open Access Journals (Sweden)

    M. Wilkinson

    2012-12-01

    Full Text Available The carbon balance of an 80-yr-old deciduous oak plantation in the temperate oceanic climate of the south-east of Great Britain was measured by eddy covariance over 12 yr (1999–2010. The mean annual net ecosystem productivity (NEP was 486 g C m−2 yr−1 (95% CI of ±73 g C m−2 yr−1, and this was partitioned into a gross primary productivity (GPP of 2034 ± 145 g C m−2 yr−1, over a 165 (±6 day growing season, and an annual loss of carbon through respiration and decomposition (ecosystem respiration, Reco of 1548 ± 122 g C m−2 yr−1. Although the maximum variation of NEP between years was large (333 g C m−2 yr−1, the ratio of Reco/GPP remained relatively constant (0.76 ± 0.02 CI. Some anomalies in the annual patterns of the carbon balance could be linked to particular weather events, such as low summer solar radiation and low soil moisture content (values below 30% by volume. The European-wide heat wave and drought of 2003 did not reduce the NEP of this woodland because of good water supply from the surface-water gley soil. The inter-annual variation in estimated intercepted radiation only accounted for ~ 47% of the variation in GPP, although a significant relationship (p < 0.001 was found between peak leaf area index and annual GPP, which modified the efficiency with which incident radiation was used in net CO2 uptake. Whilst the spring start and late autumn end of the net CO2 uptake period varied substantially (range of 24 and 27 days respectively, annual GPP was not related to growing season length. Severe outbreaks of defoliating moth caterpillars, mostly Tortrix viridana L. and Operophtera brumata L., caused considerable damage to the forest canopy in 2009 and 2010, resulting in reduced GPP in these two years. Inter-annual variation in

  2. Seasonal and Inter-Annual Analysis of Chlorophyll-a and Inherent Optical Properties from Satellite Observations in the Inner and Mid-Shelves of the South of Buenos Aires Province (Argentina

    Directory of Open Access Journals (Sweden)

    Ana L. Delgado

    2015-09-01

    Full Text Available The aim of this study is to describe and understand the seasonal and inter-annual physical and biological dynamics of the inner and mid shelves of the Southwestern Buenos Aires Province (Argentina. We used chlorophyll-a (chl-a concentrations and inherent optical properties (IOPs, derived from ocean color products between 2002 and 2010, as a proxy for the physical and biological parameters of interest. This study focuses on the absorption by phytoplankton, aph(443, particulate backscattering, bbp(443, and absorption due to dissolved and particulate detrital matter, adg(443, and chl-a derived from a multiband quasi-analytical algorithm (QAA. A regionalization based on the coefficient of variation and the Census X-11 method were applied to define regions and to analyze the inter-annual and seasonal variability of the ocean color parameters, with regards to climate variability. The coastal zone presents the highest values of chl-a with two maxima in winter and autumn, while the mid-shelf shows a strong spring chl-a maximum. After 2009, all parameters under study shifted their seasonality and their magnitude changed over the entire area. In the coastal zone, mean values of aph(443 and bbp(443 increased, while in the mid-shelf, chl-a and aph(443 decreased. The observed inter-annual and seasonal behavior of the parameters is tightly related to climate variability of the study area.

  3. Intra and inter-annual structure of zooplankton communities in floodplain lakes: a long-term ecological research study

    Directory of Open Access Journals (Sweden)

    Nadson R. Simões

    2012-12-01

    Full Text Available Water flow management has significantly changed the natural dynamic of floods, which are responsible for the structure and dynamic of aquatic communities in river-floodplain systems. With the aim to elaborate a conceptual framework that describes the main ecological factors associated with zooplankton community structure in the Upper Paraná River, we investigated the mechanisms that regulate the communities structure and their response to inter-annual and hydro-sedimentological variations in the floodplain and the biological factors associated with species abundance in those communities. For this we conducted samplings every six months (potamophase in March and limnophase in September to characterize intra and inter-annual variations in community structure between 2000 and 2008. The intra-annual differences on the species richness, abundance, Shannon diversity index, and evenness, were conducted using Bayesian procedures to show probabilistic predictions of the data fit to main variation sources. Non-metric multi-dimensional scaling (NMDS, multi-response permutation procedure (MRPP, and indicator species analysis (IndVal were run to assess and characterize the seasonality of the community structure. During high water (potamophase, hydrologic connectivity favoured exchange and dispersal of species in some lakes, increasing local diversity; during low water (limnophase, higher local productivity favoured opportunistic taxa, increasing species dominance and decreasing local diversity. Food resources and density of small-size fish were biological factors associated with the seasonal dynamic of the zooplankton community; these factors were dependent on hydrosedimentological phase (potamophase or limnophase. Water levels and limnological modifications related to water flow management have promoted replacement and impoverishment of aquatic biota in affected lakes and have indicated the ecological importance of a natural dynamic flood, which displays

  4. Inter-track interference mitigation with two-dimensional variable equalizer for bit patterned media recording

    Directory of Open Access Journals (Sweden)

    Yao Wang

    2017-05-01

    Full Text Available The increased track density in bit patterned media recording (BPMR causes increased inter-track interference (ITI, which degrades the bit error rate (BER performance. In order to mitigate the effect of the ITI, signals from multiple tracks can be equalized by a 2D equalizer with 1D target. Usually, the 2D fixed equalizer coefficients are obtained by using a pseudo-random bit sequence (PRBS for training. In this study, a 2D variable equalizer is proposed, where various sets of 2D equalizer coefficients are predetermined and stored for different ITI patterns besides the usual PRBS training. For data detection, as the ITI patterns are unknown in the first global iteration, the main and adjacent tracks are equalized with the conventional 2D fixed equalizer, detected with Bahl-Cocke-Jelinek-Raviv (BCJR detector and decoded with low-density parity-check (LDPC decoder. Then using the estimated bit information from main and adjacent tracks, the ITI pattern for each island of the main track can be estimated and the corresponding 2D variable equalizers are used to better equalize the bits on the main track. This process is executed iteratively by feeding back the main track information. Simulation results indicate that for both single-track and two-track detection, the proposed 2D variable equalizer can achieve better BER and frame error rate (FER compared to that with the 2D fixed equalizer.

  5. Inter- and Intra-Observer Variability in Prostate Definition With Tissue Harmonic and Brightness Mode Imaging

    International Nuclear Information System (INIS)

    Sandhu, Gurpreet Kaur; Dunscombe, Peter; Meyer, Tyler; Pavamani, Simon; Khan, Rao

    2012-01-01

    Purpose: The objective of this study was to compare the relative utility of tissue harmonic (H) and brightness (B) transrectal ultrasound (TRUS) images of the prostate by studying interobserver and intraobserver variation in prostate delineation. Methods and Materials: Ten patients with early-stage disease were randomly selected. TRUS images of prostates were acquired using B and H modes. The prostates on all images were contoured by an experienced radiation oncologist (RO) and five equally trained observers. The observers were blinded to information regarding patient and imaging mode. The volumes of prostate glands and areas of midgland slices were calculated. Volumes contoured were compared among the observers and between observer group and RO. Contours on one patient were repeated five times by four observers to evaluate the intraobserver variability. Results: A one-sample Student t-test showed the volumes outlined by five observers are in agreement (p > 0.05) with the RO. Paired Student t-test showed prostate volumes (p = 0.008) and midgland areas (p = 0.006) with H mode were significantly smaller than that with B mode. Two-factor analysis of variances showed significant interobserver variability (p < 0.001) in prostate volumes and areas. Inter- and intraobserver consistency was quantified as the standard deviation of mean volumes and areas, and concordance indices. It was found that for small glands (≤35 cc) H mode provided greater interobserver consistency; however, for large glands (≥35 cc), B mode provided more consistent estimates. Conclusions: H mode provided superior inter- and intraobserver agreement in prostate volume definition for small to medium prostates. In large glands, H mode does not exhibit any additional advantage. Although harmonic imaging has not proven advantageous for all cases, its utilization seems to be judicious for small prostates.

  6. How plantar exteroceptive efficiency modulates postural and oculomotor control: inter-individual variability

    Directory of Open Access Journals (Sweden)

    Arnaud eFoisy

    2016-05-01

    Full Text Available In a previous experiment, we showed that among young and healthy subjects, thin plantar inserts improve postural control and modify vergence amplitudes. In this experiment, however, significant inter-individual variability was observed. We hypothesize that its origin could be attributed to a different reliance upon feet cutaneous afferents. In order to test this hypothesis, we re-analyzed the data relative to 31 young (age 25,7±3,8 and healthy subjects who participated in the first experiment after having classified them into two groups depending on their Plantar Quotient (PQ = Surface area of CoP foam / Surface area of CoP firm ground x100. Foam decreases the information arising from the feet, normally resulting in a PQ>100. Hence, the PQ provides information on the weight of plantar cutaneous afferents used in postural control. Twelve people were Plantar-Independent Subjects, as indicated by a PQ<100. These individuals did not behave like the Normal Plantar Quotient Subjects: they were almost insensitive to the plantar stimulations in terms of postural control and totally insensitive in terms of oculomotor control. We conclude that the inter-individual variability observed in our first experiment is explained by the subjects’ degree of plantar reliance. We propose that plantar independence is a dysfunctional situation revealing an inefficiency in plantar cutaneous afferents. The latter could be due to a latent somatosensory dysfunction generating a noise which prevents the CNS from correctly processing and using feet somatosensory afferents both for balance and vergence control: Plantar Irritating Stimulus. Considering the non-noxious nature and prevalence of this phenomenon, these results can be of great interest to researchers and clinicians who attempt to trigger postural or oculomotor responses through mechanical stimulation of the foot sole.

  7. Hydrological niche separation explains seasonal and inter-annual variations of vegetation dynamics in seasonally dry tropical forests

    Science.gov (United States)

    Xu, X.; Medvigy, D.; Powers, J. S.; Becknell, J. M.; Guan, K.

    2015-12-01

    Despite ample water supply, vegetation dynamics are subject to seasonal water stress in large fraction of tropical forests. These seasonally dry tropical forests (SDTFs) account for over 40% of tropical forests, harbor high biodiversity, have large potential carbon sink due to forest recovery from human disturbance and also play a critical role in global carbon budget and inter-annual variations. Plants in this biome display notably diverse responses to seasonal and inter-annual variations of water availability, especially inter-specific variations in canopy seasonality and biomass growth. Current process-based dynamic vegetation models cannot represent these diversities and are shown to perform poorly on simulating drought responses of tropical forests, calling into question of their ability to accurately simulate future changes in SDTFs. Accumulated field observations, suggest that hydrological niche separation driven by coordinated plant functional traits is associated with plants' performance under drought. Yet, it remains not clear whether the physiology-level hydrological niche separation can explain the ecosystem-level diversity observed in SDTFs. Here, we test the theory with a model-data fusion approach. We implemented a new plant hydrodynamic module that is able to track leaf water potential at sub-daily scale in ED2 model. We further incorporated a hydrological niche separation scheme based on a meta-data analysis of key functional traits in SDTFs. Simulated ecological patterns with and without hydrological niche separation were then compared with remote-sensing and long-term field observations from an SDTF site in Palo Verde, Costa Rica. Using several numerical experiments, we specifically examine the following questions: (i) Whether hydrological niche separation can explain the diversity in canopy seasonality and biomass growth? (ii) How important are the yet uncertain belowground functional traits, especially root profile in determining canopy

  8. Inter ENSO variability and its influence over the South American monsoon system

    Directory of Open Access Journals (Sweden)

    A. R. M. Drumond

    2006-01-01

    Full Text Available Previous studies have discussed the interannual variability of a meridional seesaw of dry and wet conditions over South America (SA associated to the modulation of the South Atlantic Convergence Zone (SACZ. However, they did not explore if the variability inter ENSO (El Niño Southern Oscillation can be related to the phase changes of this dipole. To answer this question, an observational work was carried out to explore the atmospheric and Sea Surface Temperature (SST conditions related to the same ENSO signal and to opposite dipole phases. Rotated Empirical Orthogonal Function (REOF analysis was applied over normalized Chen precipitation seasonal anomalies in order to find the dipole mode in the Austral Summer (December to February. The fourth rotated mode, explaining 6.6% of the total variance, consists of positive loading over the SACZ region and negative loading over northern Argentina. Extreme events were selected and enhanced activity of SACZ during the Summer season (SACZ+ was identified in nine years: five during La Niña events (LN and two in El Niño episodes (EN. On the other hand, inhibited manifestations of this system (SACZ- were identified in seven years: four in EN and two during LN. Power spectrum analysis indicated that the interannual variability of the precipitation dipole seems to be related to the low frequency and to the quasi-biennial part of ENSO variability. The ENSO events with the same signal can present opposite phases for the dipole. The results suggest that the displacement of the convection over Indonesia and western Pacific can play an important role to modulate the seesaw pattern.

  9. Effects of modified Pilates on variability of inter-joint coordination during walking in the elderly.

    Science.gov (United States)

    Yoon, Sukhoon; Kim, Joo Nyeon; Lim, Hee Sung

    2016-12-01

    [Purpose] This study aimed to examine the effects of an 8-week modified Pilates program on the variability of inter-joint coordination in the elderly during walking. [Subjects and Methods] Twenty elderly participants with no recent history of orthopedic abnormalities (age, 67.9 ± 2.7 years; height, 163.7 ± 8.9 cm; weight, 67.1 ± 11.6 kg) were recruited for this study and randomly allocated to a modified Pilates exercise group or a control group. Three-dimensional motion analysis was performed on both groups to evaluate the effects of the Pilates exercise. [Results] There was no significant difference in the joint variability of the ankle, knee, and hip joints between the groups, both before training and after training. However, there was a significant increase in the hip-knee deviation phase value in the exercise group after the program was completed, and this increase was also significant when compared with that in the control group. [Conclusion] This study has demonstrated that an 8-week modified Pilates exercise program can have a positive impact on the gait of elderly participants, potentially by enhancing neuromuscular adjustment, which may have positive implications for reducing their fall risk.

  10. Climate Variability and Inter-Provincial Migration in South America, 1970-2011.

    Science.gov (United States)

    Thiede, Brian; Gray, Clark; Mueller, Valerie

    2016-11-01

    We examine the effect of climate variability on human migration in South America. Our analyses draw on over 21 million observations of adults aged 15-40 from 25 censuses conducted in eight South American countries. Addressing limitations associated with methodological diversity among prior studies, we apply a common analytic approach and uniform definitions of migration and climate across all countries. We estimate the effects of climate variability on migration overall and also investigate heterogeneity across sex, age, and socioeconomic groups, across countries, and across historical climate conditions. We also disaggregate migration by the rural/urban status of destination. We find that exposure to monthly temperature shocks has the most consistent effects on migration relative to monthly rainfall shocks and gradual changes in climate over multi-year periods. We also find evidence of heterogeneity across demographic groups and countries. Analyses that disaggregate migration by the rural/urban status of destination suggest that much of the climate-related inter-province migration is directed toward urban areas. Overall, our results underscore the complexity of environment-migration linkages and challenge simplistic narratives that envision a linear and monolithic migratory response to changing climates.

  11. Breast cancer MRI radiomics: An overview of algorithmic features and impact of inter-reader variability in annotating tumors.

    Science.gov (United States)

    Saha, Ashirbani; Harowicz, Michael R; Mazurowski, Maciej A

    2018-04-16

    To review features used in MRI radiomics of breast cancer and study the inter-reader stability of the features METHODS: We implemented 529 algorithmic features that can be extracted from tumor and fibroglandular tissue (FGT) in breast MRIs. The features were identified based on a review of the existing literature with consideration of their usage, prognostic ability, and uniqueness. The set was then extended so that it comprehensively describes breast cancer imaging characteristics. The features were classified into 10 groups based on the type of data used to extract them and the type of calculation being performed. For the assessment of inter-reader variability, 4 fellowship-trained readers annotated tumors on pre-operative dynamic contrast enhanced MRIs for 50 breast cancer patients. Based on the annotations, an algorithm automatically segmented the image and extracted all features resulting in one set of features for each reader. For a given feature, the inter-reader stability was defined as the intra-class correlation coefficient (ICC) computed using the feature values obtained through all readers for all cases. The average inter-reader stability for all features was 0.8474 (95% CI: 0.8068-0.8858). The mean inter-reader stability was lower for tumor-based features (0.6348, 95% CI: 0.5391-0.7257) than FGT-based features (0.9984, 95% CI: 0.9970-0.9992). The feature group with the highest inter-reader stability quantifies breast and FGT volume. The feature group with the lowest inter-reader stability quantifies variations in tumor enhancement. Breast MRI radiomics features widely vary in terms of their stability in the presence of inter-reader variability. Appropriate measures need to be taken for reducing this variability in tumor-based radiomics. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  12. Regional peculiarities in the inter-annual distribution of the red 630.0 nm line nightglow intensities over Abastumani

    Science.gov (United States)

    Toriashvili, L.; Didebulidze, G. G.; Todua, M.

    2017-12-01

    Peculiarities of the inter-annual distribution of atomic oxygen red OI 630.0 nm line nightglow intensity observed from Abastumani Astrophysical Observatory (41.75 N; 42.82 E) are considered, using the long-term dataset. This distribution demonstrates semi-annual and annual-like variations which occur during solar minimum, as well as maximum phases. The maximum values of the red line intensities are in Summer, however in June it is lower than in May and July, which may be due to regional effects. This phenomenon is considered as a the possible result of regional dynamical processes influencing the behavior of the ionosphere F2 layer which cause changes of electrons/ions densities in the 630.0 nm line luminous region (maximum luminous layer is at about 230-280 km). Using the red line intensities and ionosphere F2 layer electron density data of the IRI-12 model, the changes of meridional thermospheric wind velocities are estimated for this mid-latitude region. These meridional and vertical wind field changes causes of variations of the red line intensities in June can be caused by tidal wind and accompanied by atmospheric gravity waves activities.

  13. Inter-annual Variations in Snow/Firn Density over the Greenland Ice Sheet by Combining GRACE gravimetry and Envisat Altimetry

    Science.gov (United States)

    Su, X.; Shum, C. K.; Guo, J.; Howat, I.; Jezek, K. C.; Luo, Z.; Zhou, Z.

    2017-12-01

    Satellite altimetry has been used to monitor elevation and volume change of polar ice sheets since the 1990s. In order to derive mass change from the measured volume change, different density assumptions are commonly used in the research community, which may cause discrepancies on accurately estimating ice sheets mass balance. In this study, we investigate the inter-annual anomalies of mass change from GRACE gravimetry and elevation change from Envisat altimetry during years 2003-2009, with the objective of determining inter-annual variations of snow/firn density over the Greenland ice sheet (GrIS). High positive correlations (0.6 or higher) between these two inter-annual anomalies at are found over 93% of the GrIS, which suggests that both techniques detect the same geophysical process at the inter-annual timescale. Interpreting the two anomalies in terms of near surface density variations, over 80% of the GrIS, the inter-annual variation in average density is between the densities of snow and pure ice. In particular, at the Summit of Central Greenland, we validate the satellite data estimated density with the in situ data available from 75 snow pits and 9 ice cores. This study provides constraints on the currently applied density assumptions for the GrIS.

  14. Apparent mass of the human body in the vertical direction: Inter-subject variability

    Science.gov (United States)

    Toward, Martin G. R.; Griffin, Michael J.

    2011-02-01

    The biodynamic responses of the seated human body to whole-body vibration vary considerably between people, but the reasons for the variability are not well understood. This study was designed to determine how the physical characteristics of people affect their apparent mass and whether inter-subject variability is influenced by the magnitude of vibration and the support of a seat backrest. The vertical apparent masses of 80 seated adults (41 males and 39 females aged 18-65) were measured at frequencies between 0.6 and 20 Hz with four backrest conditions (no backrest, upright rigid backrest, reclined rigid backrest, reclined foam backrest) and with three magnitudes of random vibration (0.5, 1.0 and 1.5 m s -2 rms). Relationships between subject physical characteristics (age, gender, weight, and anthropometry) and subject apparent mass were investigated with multiple regression models. The strongest predictor of the modulus of the vertical apparent mass at 0.6 Hz, at resonance, and at 12 Hz was body weight, with other factors having only a marginal effect. After correction for other variables, the principal resonance frequency was most consistently associated with age and body mass index. As age increased from 18 to 65 years, the resonance frequency increased by up to 1.7 Hz, and when the body mass index was increased from 18 to 34 kg m -2 the resonance frequency decreased by up to 1.7 Hz. These changes were greater than the 0.9-Hz increase in resonance frequency between sitting without a backrest and sitting with a reclined rigid backrest, and greater than the 1.0-Hz reduction in resonance frequency when the magnitude of vibration increased from 0.5 to 1.5 m s -2 rms. It is concluded that the effects of age, body mass index, posture, vibration magnitude, and weight should be taken into account when defining the vertical apparent mass of the seated human body.

  15. Thymoma and inter-relationships between clinical variables: a multicentre study in 537 patients.

    Science.gov (United States)

    Filosso, Pier Luigi; Venuta, Federico; Oliaro, Alberto; Ruffini, Enrico; Rendina, Erino Angelo; Margaritora, Stefano; Casadio, Caterina; Terzi, Alberto; Rena, Ottavio; Lococo, Filippo; Guerrera, Francesco

    2014-06-01

    In thymomas, the roles of Masaoka-Koga stage, histology and the presence of myasthenia gravis (MG) have been considered fundamental for patient management and outcomes. In this study, we retrospectively evaluated several clinical variables, with the aim of outlining their relationships and clinical/prognostic significance in resected thymoma patients. A retrospective search of our surgical database for patients operated on for thymoma in six Italian high-volume thoracic surgery centres between 2000 and 2011 was conducted. The following clinical variables were evaluated: Masaoka-Koga Stage, tumour histology, the presence of MG, other autoimmune syndromes or second tumours, the completeness of tumour resection and the development of recurrences. Five hundred and thirty-seven (273 males-51%) were retrospectively included in this study. Our results indicate that: (i) MG correlates with early Masaoka-Koga stage and B-type thymoma; (ii) Stage III-IVa tumours correlate with B-type tumour; (iii) autoimmune paraneoplastic syndromes correlate with Stage I-II thymoma; (iv) second malignancies correlate with the absence of paraneoplastic disorders and weakly with B-type tumour and (v) overall survival was influenced by Masaoka-Koga stage and completeness of surgical resection. In thymomas, Masaoka-Koga stage, histology, MG, other autoimmune syndromes and second malignancies are inter-related, but only Masaoka-Koga tumour stage, amid these clinical variables, has been demonstrated to be a strong prognostic indicator of survival. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  16. Genetic variability and inter-character associations in the mutants of Indian mustard

    International Nuclear Information System (INIS)

    Labana, K.S.; Chaurasia, B.D.; Singh, Balwant

    1980-01-01

    To study the genetic variability and the inter-character associations in Indian mustard [Brassica juncea (Linn.)Czern. and Coss. subsp. juncea Linn.], 104 radiation-induced mutants (including 'RLM 198') and 'RL 18' were grown during winter season of 1976-77 at the experimental farm of the Punjab Agricultural University. Analysis of variance revealed significant differences between the mutant genotypes for all the characters under study except for the primary branch number and siliqua number of main shoot, which were non-significant. High estimates of phenotypic coefficients of variation (pcv) and genetic coefficients of variation (gcv) were observed for secondary branch number, seed yield/plant, main shoot length and seed number/siliqua. In general, pcv estimates were higher than gcv estimates. The high estimates of both heritability and genetic advance were recorded in similar order for the plant height, seed number/siliqua, main shoot length and seed yield, in which the genetic progress could be achieved through mass selection. Seed yield was positively correlated with the primary branch number, the secondary branch number and the siliqua number of main shoot and negatively with the plant height. Shorter plant height w;.th more number of primary and secondary branches and more siliquae on main shoot were found to be good selection criteria for isolating high-yielding strains. (auth.)

  17. Multidecadal variability of atmospheric methane and the Inter Polar Gradient: 0-1800 C.E

    Science.gov (United States)

    Mitchell, L.; Brook, E.

    2010-12-01

    Atmospheric methane is a potent greenhouse gas that is responsible for ~20% of the total increase in radiative forcing since the industrial revolution. Despite its importance there is a lack of scientific understanding regarding the controls on sources and sinks. Here we present high-precision, high-resolution records of atmospheric methane from the West Antarctic Ice Sheet (WAIS) Divide 05A ice core (WDC05A, 1000-1800 C.E., [Mitchell et al., submitted.]) and preliminary measurements from the WAIS Divide deep ice core (WDC06A, 0-1800 C.E.) and the Greenland ice core (GISP2D, 0-1800 C.E.). These records have decadal scale resolution, analytical precision of period affected methane emissions. Times of war and plague when large population losses could have reduced anthropogenic emissions appear coincident with periods of decreasing global methane concentrations however anthropogenic activity cannot explain all of the observed variability. We conclude that multidecadal variability of methane over the past millennium was not controlled by temperature, precipitation, or anthropogenic activity alone and instead by some combination of these parameters. Methane records from Antarctica and Greenland can be used to reconstruct the methane Inter-Polar Gradient (IPG) which is controlled by the latitudinal distribution of sources and can provide an additional constraint on possible source scenarios. Preliminary measurements reveal that the IPG over 0-1800 C.E. is ~43 ppb and has not changed significantly over this time interval despite an increase of ~40 ppb in global concentrations. This indicates that the latitudinal distribution of methane sources has also not experienced significant changes. Initial efforts to model the IPG will be presented.

  18. Inter- and intra-observer variability in prostate definition with tissue harmonic and brightness mode imaging.

    Science.gov (United States)

    Sandhu, Gurpreet Kaur; Dunscombe, Peter; Meyer, Tyler; Pavamani, Simon; Khan, Rao

    2012-01-01

    The objective of this study was to compare the relative utility of tissue harmonic (H) and brightness (B) transrectal ultrasound (TRUS) images of the prostate by studying interobserver and intraobserver variation in prostate delineation. Ten patients with early-stage disease were randomly selected. TRUS images of prostates were acquired using B and H modes. The prostates on all images were contoured by an experienced radiation oncologist (RO) and five equally trained observers. The observers were blinded to information regarding patient and imaging mode. The volumes of prostate glands and areas of midgland slices were calculated. Volumes contoured were compared among the observers and between observer group and RO. Contours on one patient were repeated five times by four observers to evaluate the intraobserver variability. A one-sample Student t-test showed the volumes outlined by five observers are in agreement (p > 0.05) with the RO. Paired Student t-test showed prostate volumes (p = 0.008) and midgland areas (p = 0.006) with H mode were significantly smaller than that with B mode. Two-factor analysis of variances showed significant interobserver variability (p standard deviation of mean volumes and areas, and concordance indices. It was found that for small glands (≤35 cc) H mode provided greater interobserver consistency; however, for large glands (≥35 cc), B mode provided more consistent estimates. H mode provided superior inter- and intraobserver agreement in prostate volume definition for small to medium prostates. In large glands, H mode does not exhibit any additional advantage. Although harmonic imaging has not proven advantageous for all cases, its utilization seems to be judicious for small prostates. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  19. Clinical Factors Underlying the Inter-individual Variability of the Resting Motor Threshold in Navigated Transcranial Magnetic Stimulation Motor Mapping.

    Science.gov (United States)

    Sollmann, Nico; Tanigawa, Noriko; Bulubas, Lucia; Sabih, Jamil; Zimmer, Claus; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

    2017-01-01

    Correctly determining individual's resting motor threshold (rMT) is crucial for accurate and reliable mapping by navigated transcranial magnetic stimulation (nTMS), which is especially true for preoperative motor mapping in brain tumor patients. However, systematic data analysis on clinical factors underlying inter-individual rMT variability in neurosurgical motor mapping is sparse. The present study examined 14 preselected clinical factors that may underlie inter-individual rMT variability by performing multiple regression analysis (backward, followed by forward model comparisons) on the nTMS motor mapping data of 100 brain tumor patients. Data were collected from preoperative motor mapping of abductor pollicis brevis (APB), abductor digiti minimi (ADM), and flexor carpi radialis (FCR) muscle representations among these patients. While edema and age at exam in the ADM model only jointly reduced the unexplained variance significantly, the other factors kept in the ADM model (gender, antiepileptic drug intake, and motor deficit) and each of the factors kept in the APB and FCR models independently significantly reduced the unexplained variance. Hence, several clinical parameters contribute to inter-individual rMT variability and should be taken into account during initial and follow-up motor mappings. Thus, the present study adds basic evidence on inter-individual rMT variability, whereby some of the parameters are specific to brain tumor patients.

  20. Annual and Seasonal Variability of Net Heat Budget in the Northern Indian Ocean

    Science.gov (United States)

    Pinker, Rachel T.; Bentamy, Abderrahim; Chen, Wen; Kumar, M. R. Ramesh; Mathew, Simi; Venkatesan, Ramasamy

    2017-04-01

    In this study we investigate the spatial and temporal features of the net heat budget over the Northern Indian Ocean (focusing on the Arabian Sea and the Bay of Bengal), using satellite and numerical model estimates. The main objective is to characterize the annual, seasonal, and inter-annual patterns over this basin of climatic significance. To assess the temporal variability, several turbulent and radiative fluxes are used The turbulent fluxes are based on information from the Institut Français pout la Recherche et l'Exploitation de la MER (IFREMER V3), the Hamburg Ocean-Atmosphere Parameters from Satellite (HOAPS V3), the SEAFLUX V1, the Japanese Ocean Flux Data sets with Use of Remote Sensing Observations (J-OFURO V2), the Objective Analysis Fluxes (OAFlux V2), the European Center for Medium Weather Forecasts (ECMWF), the ERA Interim, the National centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis, CFSR, and the National Aeronautics Space Administration (NASA) Modern Era Retrospective Analysis for Research and Application (MERRA). The radiative fluxes, both shortwave and longwave, include those produced at the University of Maryland (UMD) as well as those derived from several of the above mentioned numerical models. An attempt will be made to evaluate the various fluxes against buoy observations such as those from the RAMA array. The National Institute of Ocean Technology, Chennai, India under its Ocean Observation Program has deployed a series of OMNI Buoys both in the Arabian Sea and the Bay of Bengal. These buoys are equipped with sensors to measure the radiation as well as other parameters. Comparison has been done with the OMNI observations and good agreement has been found with the current set-up of the instrument at a 3 m level. We found significant differences between the various products at specific locations. The ultimate objective is to investigates the sources of the differences in terms of atmospheric variables (surface

  1. Inter-species and intra-annual variations of moss nitrogen utilization: Implications for nitrogen deposition assessment.

    Science.gov (United States)

    Dong, Yu-Ping; Liu, Xue-Yan; Sun, Xin-Chao; Song, Wei; Zheng, Xu-Dong; Li, Rui; Liu, Cong-Qiang

    2017-11-01

    Moss nitrogen (N) concentrations and natural 15 N abundance (δ 15 N values) have been widely employed to evaluate annual levels and major sources of atmospheric N deposition. However, different moss species and one-off sampling were often used among extant studies, it remains unclear whether moss N parameters differ with species and different samplings, which prevented more accurate assessment of N deposition via moss survey. Here concentrations, isotopic ratios of bulk carbon (C) and bulk N in natural epilithic mosses (Bryum argenteum, Eurohypnum leptothallum, Haplocladium microphyllum and Hypnum plumaeforme) were measured monthly from August 2006 to August 2007 at Guiyang, SW China. The H. plumaeforme had significantly (P < 0.05) lower bulk N concentrations and higher δ 13 C values than other species. Moss N concentrations were significantly (P < 0.05) lower in warmer months than in cooler months, while moss δ 13 C values exhibited an opposite pattern. The variance component analyses showed that different species contributed more variations of moss N concentrations and δ 13 C values than different samplings. Differently, δ 15 N values did not differ significantly between moss species, and its variance mainly reflected variations of assimilated N sources, with ammonium as the dominant contributor. These results unambiguously reveal the influence of inter-species and intra-annual variations of moss N utilization on N deposition assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Inter- and intra-strain variability of tandem repeats in Mycoplasma pneumoniae based on next-generation sequencing data.

    Science.gov (United States)

    Zhang, Jing; Song, Xiaohong; Ma, Marella J; Xiao, Li; Kenri, Tsuyoshi; Sun, Hongmei; Ptacek, Travis; Li, Shaoli; Waites, Ken B; Atkinson, T Prescott; Shibayama, Keigo; Dybvig, Kevin; Feng, Yanmei

    2017-02-01

    To characterize inter- and intra-strain variability of variable-number tandem repeats (VNTRs) in Mycoplasma pneumoniae to determine the optimal multilocus VNTR analysis scheme for improved strain typing. Whole genome assemblies and next-generation sequencing data from diverse M. pneumoniae isolates were used to characterize VNTRs and their variability, and to compare the strain discriminability of new VNTR and existing markers. We identified 13 VNTRs including five reported previously. These VNTRs displayed different levels of inter- and intra-strain copy number variations. All new markers showed similar or higher discriminability compared with existing VNTR markers and the P1 typing system. Our study provides novel insights into VNTR variations and potential new multilocus VNTR analysis schemes for improved genotyping of M. pneumoniae.

  3. Description, evaluation and clinical decision making according to various fetal heart rate patterns. Inter-observer and regional variability

    DEFF Research Database (Denmark)

    Lidegaard, O; Bøttcher, L M; Weber, Tom

    1992-01-01

    At 10 Danish obstetrical departments, 116 residents (42 senior and 74 junior) participated in a study to assess inter-observer and regional variability in the description and evaluation of and clinical decision regarding 11 fetal heart rate patterns. The 11 traces included normal as well as patho......At 10 Danish obstetrical departments, 116 residents (42 senior and 74 junior) participated in a study to assess inter-observer and regional variability in the description and evaluation of and clinical decision regarding 11 fetal heart rate patterns. The 11 traces included normal as well...... and the presence of silent or sinusoidal pattern (87-94% on an arbitrary 0-100% scale), and low regarding the assessment of variability and type of deceleration (50-72%). The degree of agreement in interpreting heart rate patterns was 59% (on an arbitrary 0-100% scale). Senior residents generally interpreted...

  4. Seasonal and inter-annual variations of dissolved oxygen in the northwestern Mediterranean Sea (DYFAMED site)

    Science.gov (United States)

    Coppola, Laurent; Legendre, Louis; Lefevre, Dominique; Prieur, Louis; Taillandier, Vincent; Diamond Riquier, Emilie

    2018-03-01

    Dissolved oxygen (O2) is a relevant tracer to interpret variations of both water mass properties in the open ocean and biological production in the surface layer of both coastal and open waters. Deep-water formation is very active in the northwestern Mediterranean Sea, where it influences intermediate and deep waters properties, nutrients replenishment and biological production. This study analyses, for the first time, the 20-year time series of monthly O2 concentrations at the DYFAMED long-term sampling site in the Ligurian Sea. Until the winters of 2005 and 2006, a thick and strong oxygen minimum layer was present between 200 and 1300 m because dense water formation was then local, episodic and of low intensity. In 2005-2006, intense and rapid deep convection injected 24 mol O2 m-2 between 350 and 2000 m from December 2005 to March 2006. Since this event, the deep layer has been mostly ventilated during winter time by newly formed deep water spreading from the Gulf of Lion 250 km to the west and by some local deep mixing in early 2010, 2012 and 2013. In the context of climate change, it is predicted that the intensity of deep convection will become weaker in the Mediterranean, which could potentially lead to hypoxia in intermediate and deep layers with substantial impact on marine ecosystems. With the exception of winters 2005 and 2006, the O2 changes in surface waters followed a seasonal trend that reflected the balance between air-sea O2 exchanges, changes in the depth of the mixed layer and phytoplankton net photosynthesis. We used the 20-year O2 time series to estimate monthly and annual net community production. The latter was 7.1 mol C m-2 yr-1, consistent with C-14 primary production determinations and sediment-trap carbon export fluxes at DYFAMED.

  5. Seasonal and inter-annual variations of leaf-level photosynthesis and soil respiration in the representative ecosystems of the Okavango Delta, Botswana

    NARCIS (Netherlands)

    Mantlana, K.B.

    2008-01-01

    Seasonal and inter-annual leaf-level photosynthesis and soil respiration measurements were conducted in representative ecosystems of the Okavango Delta, Botswana, that differ in their long-term soil water content: the permanent swamp, the seasonal floodplain, the rain-fed grassland and the mopane

  6. Inter-scan and inter-observer tumour volume delineation variability on cone beam computed tomography in patients treated with stereotactic body radiation therapy for early-stage non-small cell lung cancer.

    Science.gov (United States)

    Hou, Ying; Lee, Stephanie; Agrawal, Vishesh; Romano, John; Baldini, Elizabeth H; Chen, Aileen B; Kozono, David E; Killoran, Joseph H; Wagar, Matthew; Hacker, Fred L; Aerts, Hugo Jwl; Lewis, John H; Mak, Raymond H

    2017-02-01

    Quantification of volume changes on cone beam computed tomography (CBCT) during lung stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) may provide a useful radiological marker for radiation response and for adaptive treatment planning. This study quantifies inter-scan and inter-observer variability in tumour volume delineation on CBCT. Three clinicians independently contoured the primary gross tumour volume (GTV) manually on CBCTs taken immediately before SBRT treatment (pre) and after the same SBRT treatment (post) for 19 NSCLC patients. Relative volume differences (RVD) were calculated between the pre- and post-CBCTs for a given treatment and between any two of three observers for a given CBCT. Coefficient of variation (CV) was used to quantitatively measure and compare the extent of variability. Inter-observer variability had a significantly higher CV of 0.15 ± 0.13 compared to inter-scan CV of 0.03 ± 0.04 with P < 0.0001. The greatest variability was observed with tumours (<2 cm in diameter) versus larger tumours with 95% limit of agreement (LOA) (Mean ± Standard Deviation) of 1.90% ± 19.55% vs. -0.97% ± 12.26% for inter-scan RVD and 29.99% ± 73.84% vs. 9.37% ± 29.95% for inter-observer RVD respectively. Inter-observer variability was greater than inter-scan variability for tumour volume delineation on CBCT with greatest variability for small tumours (<2 cm in diameter). LOA for inter-scan variability (~12%) helps defines a threshold for clinically meaningful tumour volume change during SBRT treatment for tumours with diameter greater than 2 cm, with larger thresholds needed for smaller tumours. © 2016 The Royal Australian and New Zealand College of Radiologists.

  7. Three-dimensional Mass Measurement of Subsolid Pulmonary Nodules on Chest CT: Intra and Inter-observer Variability

    Directory of Open Access Journals (Sweden)

    Huiting LIU

    2015-05-01

    Full Text Available Background and objective Subsolid pulmonary nodules tend to exhibit considerably slower growth rates than solid lesions, nevertheless, higher malignancy probability. The diagnosis of indeterminate nodules largely depends on the growth evaluation during follow-up. The growth can manifested as an increase in size or the appearance and/or subsequent increase of solid components. The mass reflect the product of volume and density and can be more sensitive in growth evaluation. However, the repeatability needs a further validation. The purpose of this study is to assess the intra and inter-observer variability of mass measurement for subsolid nodules. Methods 80 subsolid nodules in 44 patients were retrospectively enrolled. Both the volume and mass were measured by two radiologists using blind method independently. Intra-observer and inter-observer variability were analyzed and compared by Bland-Altman method intra-class correlation test and Wilcoxon test. Results Software achieved satisfied segmentation for 92.5% nodules. Of them, 35% underwent manual modification. The 95% limits of agreement for intra-observer variability were -11.5%-10.4% for mass and -8.4%-8.8% for volume. The 95% limits of agreement for inter-observer variability were -17.4%-19.3% for mass and -17.9%-19.4% for volume.The intra-class correlation foefficients between volume and mass measument was 0.95 and 0.93 (both P<0.001 and no significant differences (P=0.78, 0.09 was found for intra- and inter-observer variability. Manual modification of the segmentation caused the worse mass measurement repeatability in spite of the reader satisfaction. Conclusion The repeatability of mass measurement has no significant difference with that of volume measurement and may act as a reliable method in the follow-up of subsolid nodules.

  8. Long-term inter-annual variability of a cyclonic gyre in the western Irish Sea

    Science.gov (United States)

    Olbert, Agnieszka I.; Hartnett, Michael; Dabrowski, Tomasz; Mikolajewicz, Uwe

    2011-09-01

    The western Irish Sea gyre (WISG) is a cyclonic baroclinic flow around a dome of stagnant water which develops each year during the heating season in the western Irish Sea. Research was carried out to determine long-term changes in the strength of stratification within WISG and associated changes in the gyre structure, circulation patterns and retentive properties. Model simulations were carried out for the 58-year period 1951-2008. The characteristics of the gyre were quantified by means of potential energy anomaly (PEA), measuring the strength of stratification, and total kinetic energy (KE), reflecting the strength of cyclonic circulation. Additionally, long-term changes in flushing rates within the gyre were assessed. Results show that stratification in the western Irish Sea consistently begins to develop in March, increases linearly from April till June, peaks at the beginning of July and remains at close to maximum level throughout the month of July, before a start of a sharp decline at the beginning of August. The strength of stratification is significantly correlated with averaged summer air temperatures and summer wind speeds. Trend analysis of PEA shows an increase in the stratification strength over the period considered; the increase of PEA peak value is accompanied by a shortening of the gyre duration and a delay in the timing of the peak value. There is also an increasing trend in the KE value, showing that the thermal stratification plays a crucial role in the hydrography of the region. Flushing analysis shows that the stronger the stratification the lower the residence time and thus the faster the removal of the material from the western Irish Sea. Residence time within WISG shortens on average by 8 days over the 58-year period.

  9. Inter Annual Variability of the California Current System and Associated Biochemical Characteristics from Prolonged Data Series

    Science.gov (United States)

    2016-06-01

    47 Table 6. Variances of the First Six Leading EOFs of Synoptic Monthly Anomaly...59 Table 7. Variances of the First Six Leading EOF’s of Synoptic Monthly Anomaly ( Ĉ...CODE 13. ABSTRACT (maximum 200 words) This research investigates the California Current System (CCS) utilizing Synoptic Monthly Gridded World

  10. Long term ice sheet mass change rates and inter-annual variability from GRACE gravimetry.

    Science.gov (United States)

    Harig, C.

    2017-12-01

    The GRACE time series of gravimetry now stretches 15 years since its launch in 2002. Here we use Slepian functions to estimate the long term ice mass trends of Greenland, Antarctica, and several glaciated regions. The spatial representation shows multi-year to decadal regional shifts in accelerations, in agreement with increases in radar derived ice velocity. Interannual variations in ice mass are of particular interest since they can directly link changes in ice sheets to the drivers of change in the polar ocean and atmosphere. The spatial information retained in Slepian functions provides a tool to determine how this link varies in different regions within an ice sheet. We present GRACE observations of the 2013-2014 slowdown in mass loss of the Greenland ice sheet, which was concentrated in specific parts of the ice sheet and in certain months of the year. We also discuss estimating the relative importance of climate factors that control ice mass balance, as a function of location of the glacier/ice cap as well as the spatial variation within an ice sheet by comparing gravimetry with observations of surface air temperature, ocean temperature, etc. as well as model data from climate reanalysis products.

  11. Inter-annual sea level variability in the southern South China Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    convection, decrease in cloud cover and reduction in precipitation; this situation reverses during La Niña events. Hadley circulation strengthens over the eastern Pacific but weakens over the Indo-Western Pacific (Klein et al., 1999). During the cold phase... (La Niña), intensified trade winds shift the warm pool farther west. This plays a significant role of SLA variation during ENSO. The strength of ENSO is measured by Southern Oscillation Index (SOI). The SOI is the surface air pressure difference...

  12. Annual to Inter-Decadal Variability in Surface Air Temperature Along ...

    African Journals Online (AJOL)

    in the south-eastern part of the Indian Ocean, counteracted by ... Pacific. Decadal Oscillation (PDO) Index (Mantua et al., 1997) is the leading principal component of. North Pacific monthly SST anomalies poleward of 20°N. Monthly mean global average SST anomalies ... subtropical anticyclones, tropical cyclones, monsoon ...

  13. Inter-annual variability of CO2 exchanges between an emersed tidal flat and the atmosphere

    NARCIS (Netherlands)

    Klaassen, Wim; Spilmont, Nicolas

    2012-01-01

    Carbon dioxide (CO2) exchanges between a tidal flat (Wadden Sea, Netherlands) and the atmosphere were measured during a three-year survey. CO2 exchanges were monitored during 1-2 days each month between September 2006 and September 2009 using a flux chamber. The flux of CO2 was separated into two

  14. Inter-annual and spatial variability of Hamon potential evapotranspiration model coefficients

    Science.gov (United States)

    McCabe, Gregory J.; Hay, Lauren E.; Bock, Andy; Markstrom, Steven L.; Atkinson, R. Dwight

    2015-01-01

    Monthly calibrated values of the Hamon PET coefficient (C) are determined for 109,951 hydrologic response units (HRUs) across the conterminous United States (U.S.). The calibrated coefficient values are determined by matching calculated mean monthly Hamon PET to mean monthly free-water surface evaporation. For most locations and months the calibrated coefficients are larger than the standard value reported by Hamon. The largest changes in the coefficients were for the late winter/early spring and fall months, whereas the smallest changes were for the summer months. Comparisons of PET computed using the standard value of C and computed using calibrated values of C indicate that for most of the conterminous U.S. PET is underestimated using the standard Hamon PET coefficient, except for the southeastern U.S.

  15. Human activity and climate variability project: annual report 2001

    International Nuclear Information System (INIS)

    Harle, K.J.; Heijnis, H.; Henderson-Sellers, A.; Sharmeen, S.; Zahorowski, W.

    2002-01-01

    Knowledge of the state of the Australian environment, including natural climate variability, prior to colonial settlement is vital if we are to define and understand the impact of over two hundred years of post-industrial human activity on our landscape. ANSTO, in conjunction with university partners, is leading a major research effort to provide natural archives of human activity and climate variability over the last 500 years in Australia, utilising a variety of techniques, including lead-210 and radiocarbon dating and analyses of proxy indicators (such as microfossils) as well as direct evidence (such as trace elements) of human activity and climate variability. The other major project objectives were to contribute to the understanding of the impact of human induced and natural aerosols in the East Asian region on climate through analysis and sourcing of fine particles and characterisation of air samples using radon concentrations and to contribute to the improvement of land surface parameterisation schemes and investigate the potential to use stable isotopes to improve global climate models and thus improve our understanding of future climate

  16. Inter- and intra-laboratory variability of CD4 cell counts in Swaziland ...

    African Journals Online (AJOL)

    The samples were further subdivided at each laboratory: one was run at 12 hours and the second at 24 hours after venepuncture. The results of absolute CD4 count and CD4 percentage testing were compared within (intra-laboratory) and between (inter-laboratory) laboratories. Results. Among 53 participants, the mean ...

  17. What drives inter-annual variations in C flux and balance in a tropical rainforest of French Guiana?

    Science.gov (United States)

    Aguilos, Maricar; Herault, Bruno; Burban, Benoit; Wagner, Fabien; Bonal, Damien

    2017-04-01

    Amazon rainforests, a major contributor to the global carbon sink, is not on steady state and information about the long-term impact of climate change on carbon fluxes between this ecosystem and the atmosphere and the resulting balance is lacking. A thorough understanding of the forest responses to climate is indeed important to improve ecosystem process models and to reduce uncertainties in the contemporary carbon balance calculations for tropical forests. To address these issues, we examined the interannual variations in gross primary photosynthesis (GPP), ecosystem respiration (RE) and net ecosystem exchange (NEE) in a tropical rainforest in French Guiana and identified key climatic drivers influencing such changes across a 12-year long period (2004 - 2015). The study period was characterized by strong differences in climate conditions, particularly in the intensity of the long dry and the long wet seasons. Fluctuations in annual average GPP vary from 9.27 ± 1.68 g C m?2 d?1 to 11.13 ± 2.21 g C m?2 d?1. RE is more varied than GPP having a difference of 2.53 C m?2 d?1 between the minimum (8.28 ± 0.85 g C m?2 d?1) and maximum (10.80 ± 1.67 g C m?2 d?1). GPP was always higher than RE annually and the forest remained a carbon sink in an annual basis although NEE has huge interannual variability, from -0.18 ± 1.64 g C m?2 d?1 to -1.62 ± 1.65 g C m?2 d?1. Annually, the combination of global radiation (Rg), relative extractable water (REW) and soil temperature (Ts) explained 51% of the variations of GPP, 30% for RE, and 39% for NEE, but global radiation was always the best predictor variable. Seasonally, Rg was the major controlling factor for GPP (r2 = 0.58; P dry season, variations in C fluxes and balance were poorly explained by climate factors. Yet, relative extractable water was the key driver of variations in RE (r2 = 0.16; P < 0.0001) and NEE (r2 = 0.10; P < 0.0001). Biotic factors such as plant area index, tree growth or litterfall did not contribute much

  18. Inter-word variability of Hungarian affricates /ʦ, ʧ/ in the speech of monolingual children with and without language disorders.

    Science.gov (United States)

    Tar, Éva

    2014-12-01

    This study focuses on the characteristics of inter-word variability (IWV) with respect to two Hungarian affricates (/ʦ, ʧ/) produced by children with typical language development (children with TD) aged 3;0-5;11, and those with primary expressive language disorders (children with LD) with the mean age of 6;7. IWV is described in terms of frequency of occurrence, the segments realised in place of the targets and the error patterns resulting in variable production. Findings revealed that variability is characteristic of the production of /ʧ/ in younger children with TD, and of both affricates in children with LD. Beside some similarities, children with TD and those with LD differed from each other in the way in which variable productions emerged. Children with TD committed errors typical of their age, and their IWV mostly reflected developmental changes. Children with LD, however, demonstrated some indicators of phonological disorders such as the persistence of normal simplifications and chronological mismatch.

  19. The effect of inter-laboratory variability on the protein:creatinine (UPC) ratio in canine urine.

    Science.gov (United States)

    Rossi, G; Bertazzolo, W; Dondi, F; Binnella, M; Gruarin, M; Scarpa, P; Paltrinieri, S

    2015-04-01

    Quantification of proteinuria is a fundamental step in staging dogs with chronic kidney disease and in monitoring the course of disease or the efficacy of anti-proteinuric treatments. Analytical precision and accuracy of the proteinuria assessment could be affected by several factors such as biological variability, different operators and quality control materials. The aim of this study was to assess whether inter-laboratory variability could affect the urinary protein to creatinine (UPC) ratio and whether this variability may affect patient classification according to the International Renal Interest Society (IRIS) sub-staging system. The same urine samples were analysed in three different laboratories using different instruments and different reagent brands. The results of the three laboratories were highly correlated to each other although urinary protein (UP), urinary creatinine (UC) and the UPC ratio of one laboratory were found to be significantly higher than those of the other two. No significant differences between the other two laboratories were recorded. The concordance in classifying dogs according to the IRIS guidelines was good if all three proteinuria categories were analysed separately or if borderline proteinuric (BP) dogs were included in the proteinuric group, and very good if BP dogs were merged into the non-proteinuric group. The inter-laboratory variability in UPC ratio measurement was not so great as to impede the identification of proteinuric dogs, but may influence the estimation of the magnitude of proteinuria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Century-scale variability in global annual runoff examined using a water balance model

    Science.gov (United States)

    McCabe, G.J.; Wolock, D.M.

    2011-01-01

    A monthly water balance model (WB model) is used with CRUTS2.1 monthly temperature and precipitation data to generate time series of monthly runoff for all land areas of the globe for the period 1905 through 2002. Even though annual precipitation accounts for most of the temporal and spatial variability in annual runoff, increases in temperature have had an increasingly negative effect on annual runoff after 1980. Although the effects of increasing temperature on runoff became more apparent after 1980, the relative magnitude of these effects are small compared to the effects of precipitation on global runoff. ?? 2010 Royal Meteorological Society.

  1. [Three-dimensional Mass Measurement of Subsolid Pulmonary Nodules on Chest CT: Intra and Inter-observer Variability].

    Science.gov (United States)

    Liu, Huiting; Wang, Ying; Feng, Lei; Yu, Tielian

    2015-05-01

    Subsolid pulmonary nodules tend to exhibit considerably slower growth rates than solid lesions, nevertheless, higher malignancy probability. The diagnosis of indeterminate nodules largely depends on the growth evaluation during follow-up. The growth can manifested as an increase in size or the appearance and/or subsequent increase of solid components. The mass reflect the product of volume and density and can be more sensitive in growth evaluation. However, the repeatability needs a further validation. The purpose of this study is to assess the intra and inter-observer variability of mass measurement for subsolid nodules. 80 subsolid nodules in 44 patients were retrospectively enrolled. Both the volume and mass were measured by two radiologists using blind method independently. Intra-observer and inter-observer variability were analyzed and compared by Bland-Altman method intra-class correlation test and Wilcoxon test. Software achieved satisfied segmentation for 92.5% nodules. Of them, 35% underwent manual modification. The 95% limits of agreement for intra-observer variability were -11.5%-10.4% for mass and -8.4%-8.8% for volume. The 95% limits of agreement for inter-observer variability were -17.4%-19.3% for mass and -17.9%-19.4% for volume.The intra-class correlation foefficients between volume and mass measument was 0.95 and 0.93 (both Psegmentation caused the worse mass measurement repeatability in spite of the reader satisfaction. The repeatability of mass measurement has no significant difference with that of volume measurement and may act as a reliable method in the follow-up of subsolid nodules.

  2. To asses inter- and intra-observer variability for breast density and BIRADS assessment categories in mammographic reporting.

    Science.gov (United States)

    Masroor, Imrana; Rasool, Mahreen; Saeed, Shaista Afzal; Sohail, Saba

    2016-02-01

    To evaluate the inter- and intra-observer variability among radiologists in the characterisation of mammograms according to Breast Imaging Reporting and Data System assessment and breast density categories. The descriptive cross-sectional study was conducted at Aga Khan University Hospital, Karachi, from January 2014 to June 2014. Using non-probability purposive sampling, all mammograms in the study were interpreted by three radiologists on the basis of Breast Imaging Reporting and Data System categories and by assessing the breast density composition. The inter-observer variability was recorded by comparing the difference in the interpretation and categorisation of each case. Intra-observer variability was noted by comparing the differences in the two sets of results from reading the same mammogram three months apart. A total of 254 mammograms were reviewed and the mean age of patients was 55.2±11.6 years. In the first round of diagnostic imaging, there was moderate agreement among all three possible pairs of observers regarding breast density (k= 0.50-0.41), but for Breast Imaging Reporting and Data System categories the agreement was less (k=0.27-0.13). After 3 months, variability of observer 1 showed substantial agreement (k=0.65).Variability between observer 2 and observer 3 showed moderate agreement (k=0.13).In terms of categories, intra-observer differences were variable: observer 1 (?=0.61; observer 2(?=0.17); observer 3 (k=0.45). Despite standardised guidelines for reporting density and assessment categories, observer variability continues to exist.

  3. Satellites reveals the biophysical effects of forest cover change on climate at diurnal, seasonal and inter-annual time scales

    Science.gov (United States)

    Duveiller, Gregory; Alkama, Ramdane; Cescatti, Alessandro

    2017-04-01

    Changing the planet's forest cover can have a profound impact of the climate system by altering its role as a carbon sink. However, deforestation and afforestation also changes the biophysical properties of the surface such as albedo, roughness and root depth, thus altering the energy balance and the resulting surface and air temperature. The result of these competing biophysical processes varies spatially and seasonally, and can lead to either warming or cooling depending on which process dominates. The main tools to characterize such plant-climate interactions for both the past and future are land surface models embedded in larger Earth System models, yet their capacity to model biophysical effects accurately across the globe remains unclear due to the complexity of the phenomena. Alternatively, with appropriate methodologies, the climate impacts of the biophysical effects of forest cover change can be derived from space by satellite measurements of surface temperature and energy fluxes. Here we present the confrontation of two dedicated assessments that have been specifically generated for this scope with contrasting methodologies. The first is based on identifying an actual change in the local climate following an observed forest cover transition. Although it directly measures the desired effect, this method can only be applied to the places where vegetation change has effectively occurred. The second method relies on a 'space-for-time' approximation that identifies the potential impact of a plant cover transition from differences in climate amongst neighboring areas with contrasting vegetation. We show how both approaches reinforce and complement each other to provide a consolidated result across diurnal, seasonal and inter-annual time scales. We anticipate that these evidences derived from satellite records may support the benchmarking and development of Earth system models and support the inclusion of vegetation-driven biophysical processes in climate

  4. Detecting Inter-Annual Variations in the Phenology of Evergreen Conifers Using Long-Term MODIS Vegetation Index Time Series

    Directory of Open Access Journals (Sweden)

    Laura Ulsig

    2017-01-01

    Full Text Available Long-term observations of vegetation phenology can be used to monitor the response of terrestrial ecosystems to climate change. Satellite remote sensing provides the most efficient means to observe phenological events through time series analysis of vegetation indices such as the Normalized Difference Vegetation Index (NDVI. This study investigates the potential of a Photochemical Reflectance Index (PRI, which has been linked to vegetation light use efficiency, to improve the accuracy of MODIS-based estimates of phenology in an evergreen conifer forest. Timings of the start and end of the growing season (SGS and EGS were derived from a 13-year-long time series of PRI and NDVI based on a MAIAC (multi-angle implementation of atmospheric correction processed MODIS dataset and standard MODIS NDVI product data. The derived dates were validated with phenology estimates from ground-based flux tower measurements of ecosystem productivity. Significant correlations were found between the MAIAC time series and ground-estimated SGS (R2 = 0.36–0.8, which is remarkable since previous studies have found it difficult to observe inter-annual phenological variations in evergreen vegetation from satellite data. The considerably noisier NDVI product could not accurately predict SGS, and EGS could not be derived successfully from any of the time series. While the strongest relationship overall was found between SGS derived from the ground data and PRI, MAIAC NDVI exhibited high correlations with SGS more consistently (R2 > 0.6 in all cases. The results suggest that PRI can serve as an effective indicator of spring seasonal transitions, however, additional work is necessary to confirm the relationships observed and to further explore the usefulness of MODIS PRI for detecting phenology.

  5. SU-E-J-266: Cone Beam Computed Tomography (CBCT) Inter-Scan and Inter-Observer Tumor Volume Variability Assessment in Patients Treated with Stereotactic Body Radiation Therapy (SBRT) for Early Stage Non-Small Cell Lung Cancer (NSCLC)

    International Nuclear Information System (INIS)

    Hou, Y; Aileen, C; Kozono, D; Killoran, J; Wagar, M; Lee, S; Hacker, F; Aerts, H; Lewis, J; Mak, R

    2015-01-01

    Purpose: Quantification of volume changes on CBCT during SBRT for NSCLC may provide a useful radiological marker for radiation response and adaptive treatment planning, but the reproducibility of CBCT volume delineation is a concern. This study is to quantify inter-scan/inter-observer variability in tumor volume delineation on CBCT. Methods: Twenty earlystage (stage I and II) NSCLC patients were included in this analysis. All patients were treated with SBRT with a median dose of 54 Gy in 3 to 5 fractions. Two physicians independently manually contoured the primary gross tumor volume on CBCTs taken immediately before SBRT treatment (Pre) and after the same SBRT treatment (Post). Absolute volume differences (AVD) were calculated between the Pre and Post CBCTs for a given treatment to quantify inter-scan variability, and then between the two observers for a given CBCT to quantify inter-observer variability. AVD was also normalized with respect to average volume to obtain relative volume differences (RVD). Bland-Altman approach was used to evaluate variability. All statistics were calculated with SAS version 9.4. Results: The 95% limit of agreement (mean ± 2SD) on AVD and RVD measurements between Pre and Post scans were −0.32cc to 0.32cc and −0.5% to 0.5% versus −1.9 cc to 1.8 cc and −15.9% to 15.3% for the two observers respectively. The 95% limit of agreement of AVD and RVD between the two observers were −3.3 cc to 2.3 cc and −42.4% to 28.2% respectively. The greatest variability in inter-scan RVD was observed with very small tumors (< 5 cc). Conclusion: Inter-scan variability in RVD is greatest with small tumors. Inter-observer variability was larger than inter-scan variability. The 95% limit of agreement for inter-observer and inter-scan variability (∼15–30%) helps define a threshold for clinically meaningful change in tumor volume to assess SBRT response, with larger thresholds needed for very small tumors. Part of the work was funded by a Kaye

  6. SU-E-J-266: Cone Beam Computed Tomography (CBCT) Inter-Scan and Inter-Observer Tumor Volume Variability Assessment in Patients Treated with Stereotactic Body Radiation Therapy (SBRT) for Early Stage Non-Small Cell Lung Cancer (NSCLC)

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Y; Aileen, C; Kozono, D; Killoran, J; Wagar, M; Lee, S; Hacker, F; Aerts, H; Lewis, J; Mak, R [Brigham and Women’s Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: Quantification of volume changes on CBCT during SBRT for NSCLC may provide a useful radiological marker for radiation response and adaptive treatment planning, but the reproducibility of CBCT volume delineation is a concern. This study is to quantify inter-scan/inter-observer variability in tumor volume delineation on CBCT. Methods: Twenty earlystage (stage I and II) NSCLC patients were included in this analysis. All patients were treated with SBRT with a median dose of 54 Gy in 3 to 5 fractions. Two physicians independently manually contoured the primary gross tumor volume on CBCTs taken immediately before SBRT treatment (Pre) and after the same SBRT treatment (Post). Absolute volume differences (AVD) were calculated between the Pre and Post CBCTs for a given treatment to quantify inter-scan variability, and then between the two observers for a given CBCT to quantify inter-observer variability. AVD was also normalized with respect to average volume to obtain relative volume differences (RVD). Bland-Altman approach was used to evaluate variability. All statistics were calculated with SAS version 9.4. Results: The 95% limit of agreement (mean ± 2SD) on AVD and RVD measurements between Pre and Post scans were −0.32cc to 0.32cc and −0.5% to 0.5% versus −1.9 cc to 1.8 cc and −15.9% to 15.3% for the two observers respectively. The 95% limit of agreement of AVD and RVD between the two observers were −3.3 cc to 2.3 cc and −42.4% to 28.2% respectively. The greatest variability in inter-scan RVD was observed with very small tumors (< 5 cc). Conclusion: Inter-scan variability in RVD is greatest with small tumors. Inter-observer variability was larger than inter-scan variability. The 95% limit of agreement for inter-observer and inter-scan variability (∼15–30%) helps define a threshold for clinically meaningful change in tumor volume to assess SBRT response, with larger thresholds needed for very small tumors. Part of the work was funded by a Kaye

  7. Stability of FDG-PET Radiomics features - An integrated analysis of test-retest and inter-observer variability

    Energy Technology Data Exchange (ETDEWEB)

    Leijenaar, Ralph T. H.; Carvalho, Sara; Rios Velazquez, Emmanuel [Dept. of Radiation Oncology (MAASTRO), GROW-School for Oncology and Developmental Biology, Maastricht Univ. Medical Center, Maastricht (Netherlands)] [and others

    2013-10-15

    Purpose: Besides basic measurements as maximum standardized uptake value (SUV){sub max} or SUV{sub mean} derived from 18F-FDG positron emission tomography (PET) scans, more advanced quantitative imaging features (i.e. 'Radiomics' features) are increasingly investigated for treatment monitoring, outcome prediction, or as potential biomarkers. With these prospected applications of Radiomics features, it is a requisite that they provide robust and reliable measurements. The aim of our study was therefore to perform an integrated stability analysis of a large number of PET-derived features in non-small cell lung carcinoma (NSCLC), based on both a test-retest and an inter-observer setup. Methods: Eleven NSCLC patients were included in the test-retest cohort. Patients underwent repeated PET imaging within a one day interval, before any treatment was delivered. Lesions were delineated by applying a threshold of 50 % of the maximum uptake value within the tumor. Twenty-three NSCLC patients were included in the inter-observer cohort. Patients underwent a diagnostic whole body PET-computed tomography (CT). Lesions were manually delineated based on fused PET-CT, using a standardized clinical delineation protocol. Delineation was performed independently by five observers, blinded to each other. Fifteen first order statistics, 39 descriptors of intensity volume histograms, eight geometric features and 44 textural features were extracted. For every feature, test-retest and inter-observer stability was assessed with the intra-class correlation coefficient (ICC) and the coefficient of variability, normalized to mean and range. Similarity between test-retest and inter-observer stability rankings of features was assessed with Spear man's rank correlation coefficient. Results: Results showed that the majority of assessed features had both a high test-retest (71%) and inter-observer (91%) stability in terms of their ICC. Overall, features more stable in repeated PET

  8. Human activity and climate variability project - annual report 2002

    International Nuclear Information System (INIS)

    Chambers, S.; Harle, K.J.; Sharmeen, S.; Zahorowski, W.; Cohen, D.; Heijnis, H.; Henderson-Sellers, A

    2002-01-01

    Work is well underway on identifying the spatial and temporal extent, direction and range of trace element transport across Tasmania through analysis of lake sediments; A follow up investigation of sedimentation and pollution in the Nattai River catchment following the devastating 2001 bushfires in the region has been completed; The project has been extended to include investigations of evidence of human impacts in the highly sensitive and ecologically important Great Lakes of coastal NSW. This has involved the expansion of our collaboration to include Geoscience Australia; Contributions have been made to the IGBP HITE project. Further contributions will be made as the evidence gathered is drawn together and interpreted; Over the coming year, focus will be placed on completion of the investigation of the extent of aerial transport of trace elements across Tasmania over the last 200 years as well as evidence for human activity and impacts on the Great Lakes region of NSW. Further investigation of potential climate signals from sites in northern Australia will also be made. The first 12 months of data for all ACE-Asia radon and fine particle sites is now available with preliminary analyses performed; The seasonal variability of background radon concentration at each of the radon monitoring sites has been characterised for the available data; Major components related to industrial pollution and soil sources in China have been identified and quantified; Regional and seasonal variations and trends in aerosol constituents have been measured and compared across more than 2.8Mk 2 of sampling area; The Hok Tsui and Kosan detectors were visited for general maintenance and recalibration; A grant application to the APN has been submitted in support of regional inventory analyses based on radon time series; Progress on the processing and interpretation of radon data was presented at the Cape Grim Science Meeting (6-7 February 2002) and the 7th Biennial SPERA Conference on

  9. Inter-Fraction Tumor Volume Response during Lung Stereotactic Body Radiation Therapy Correlated to Patient Variables.

    Directory of Open Access Journals (Sweden)

    Samer Salamekh

    Full Text Available Analyze inter-fraction volumetric changes of lung tumors treated with stereotactic body radiation therapy (SBRT and determine if the volume changes during treatment can be predicted and thus considered in treatment planning.Kilo-voltage cone-beam CT (kV-CBCT images obtained immediately prior to each fraction were used to monitor inter-fraction volumetric changes of 15 consecutive patients (18 lung nodules treated with lung SBRT at our institution (45-54 Gy in 3-5 fractions in the year of 2011-2012. Spearman's (ρ correlation and Spearman's partial correlation analysis was performed with respect to patient/tumor and treatment characteristics. Multiple hypothesis correction was performed using False Discovery Rate (FDR and q-values were reported.All tumors studied experienced volume change during treatment. Tumor increased in volume by an average of 15% and regressed by an average of 11%. The overall volume increase during treatment is contained within the planning target volume (PTV for all tumors. Larger tumors increased in volume more than smaller tumors during treatment (q = 0.0029. The volume increase on CBCT was correlated to the treatment planning gross target volume (GTV as well as internal target volumes (ITV (q = 0.0085 and q = 0.0039 respectively and could be predicted for tumors with a GTV less than 22 mL. The volume increase was correlated to the integral dose (ID in the ITV at every fraction (q = 0.0049. The peak inter-fraction volume occurred at an earlier fraction in younger patients (q = 0.0122.We introduced a new analysis method to follow inter-fraction tumor volume changes and determined that the observed changes during lung SBRT treatment are correlated to the initial tumor volume, integral dose (ID, and patient age. Furthermore, the volume increase during treatment of tumors less than 22mL can be predicted during treatment planning. The volume increase remained significantly less than the overall PTV expansion, and radiation

  10. Dental microwear texture analysis of extant sika deer with considerations on inter-microscope variability and surface preparation protocols

    Directory of Open Access Journals (Sweden)

    Mugino O. Kubo

    2017-12-01

    Full Text Available Recently, dental microwear texture analysis (DMTA has been applied to various kinds of vertebrates to infer dietary preference. More data are needed on inter-microscope variability to assure the objectivity and repeatability of this method. In the present paper, we investigated inter-microscope variability between two confocal laser microscopes with different specifications, as well as variability due to different protocols applied to the obtained surface before DMTA. We used two different methods of DMTA: the scale sensitive fractal analysis (SSFA and the surface texture analysis (STA. We collected DMTA data of extant Japanese sika deer populations with varying diets. We found that different protocols produced significantly different results for both SSFA and STA, whereas nearly two thirds of the parameters were not significantly different between the machines when applying the same pre-analysis protocol. Finally, we analyzed DMTA data of 244 sika deer from 11 populations. Twenty nine parameters were significantly different among the populations. Tooth enamel surface of grazing sika deer is dominated by a number of well-aligned scratches, whereas that of browsing deer is more flattened and characterized by more sporadic pits. Therefore, DMTA can identify intraspecific variation in diets, which is smaller than the interspecific dietary variation in extant ruminants.

  11. Intra- and inter-observer variability in ultrasonographical measurements of the uterus and ovaries in healthy, non-pregnant queens.

    Science.gov (United States)

    Gatel, Laure; Gory, Guillaume; Chalvet-Monfray, Karine; Saunders, Jimmy H; Rault, Delphine N

    2016-02-01

    We aimed to (1) evaluate how frequently the uterus and ovaries of healthy, non-pregnant queens are visible; (2) describe their appearance; (3) take their measurements; and (4) determine intra- and inter-observer variabilities in their measurements. We hypothesised that, using a high-frequency linear probe, the uterus and ovaries could be ultrasonographically visualised during any period of the sexual cycle and with any level of operator expertise. Eight queens were enrolled in the study and the ultrasonographical appearance of their uterus and ovaries assessed with a high-frequency linear probe of 15-19 MHz. The diameter of the uterine horns, body and cervix in transverse and longitudinal sections, and the length of the ovaries were recorded. Three observers of different expertise level participated in the study, and the differences between the separate measurements made per queen were evaluated. The ovaries and the entire uterus were visualised in every queen. The ovaries were ovoid structures with submillimetric follicles during anoestrus and additional larger follicles depending on the stage of the cycle. An ovarian pattern suggesting cortex and medulla was observed in half the cases. In the uterus, the serosa was a thin hyperechoic outer rim, and layering was observed in half the cases. The cervix was difficult to identify. The intra- and inter-observer variabilities in the uterine horns and the ovaries were minimal (coefficient of variation [CV] 1.4-4.1%) compared with the differences within the queens (CV 10.9-43.4%). The longitudinal and transverse measurements of the horns and the uterine body were the same. The ovaries and uterine horns in queens are accessible ultrasonographically at any stage of their cycle, and can be measured with low intra- and inter-observer variabilities. © ISFM and AAFP 2015.

  12. The Teleconnection of the Tropical Atlantic to Indo-Pacific Sea Surface Temperatures on Inter-Annual to Centennial Time Scales: A Review of Recent Findings

    Directory of Open Access Journals (Sweden)

    Fred Kucharski

    2016-02-01

    Full Text Available In this paper, the teleconnections from the tropical Atlantic to the Indo-Pacific region from inter-annual to centennial time scales will be reviewed. Identified teleconnections and hypotheses on mechanisms at work are reviewed and further explored in a century-long pacemaker coupled ocean-atmosphere simulation ensemble. There is a substantial impact of the tropical Atlantic on the Pacific region at inter-annual time scales. An Atlantic Niño (Niña event leads to rising (sinking motion in the Atlantic region, which is compensated by sinking (rising motion in the central-western Pacific. The sinking (rising motion in the central-western Pacific induces easterly (westerly surface wind anomalies just to the west, which alter the thermocline. These perturbations propagate eastward as upwelling (downwelling Kelvin-waves, where they increase the probability for a La Niña (El Niño event. Moreover, tropical North Atlantic sea surface temperature anomalies are also able to lead La Niña/El Niño development. At multidecadal time scales, a positive (negative Atlantic Multidecadal Oscillation leads to a cooling (warming of the eastern Pacific and a warming (cooling of the western Pacific and Indian Ocean regions. The physical mechanism for this impact is similar to that at inter-annual time scales. At centennial time scales, the Atlantic warming induces a substantial reduction of the eastern Pacific warming even under CO2 increase and to a strong subsurface cooling.

  13. Image processing in digital pathology: an opportunity to solve inter-batch variability of immunohistochemical staining.

    Science.gov (United States)

    Van Eycke, Yves-Rémi; Allard, Justine; Salmon, Isabelle; Debeir, Olivier; Decaestecker, Christine

    2017-02-21

    Immunohistochemistry (IHC) is a widely used technique in pathology to evidence protein expression in tissue samples. However, this staining technique is known for presenting inter-batch variations. Whole slide imaging in digital pathology offers a possibility to overcome this problem by means of image normalisation techniques. In the present paper we propose a methodology to objectively evaluate the need of image normalisation and to identify the best way to perform it. This methodology uses tissue microarray (TMA) materials and statistical analyses to evidence the possible variations occurring at colour and intensity levels as well as to evaluate the efficiency of image normalisation methods in correcting them. We applied our methodology to test different methods of image normalisation based on blind colour deconvolution that we adapted for IHC staining. These tests were carried out for different IHC experiments on different tissue types and targeting different proteins with different subcellular localisations. Our methodology enabled us to establish and to validate inter-batch normalization transforms which correct the non-relevant IHC staining variations. The normalised image series were then processed to extract coherent quantitative features characterising the IHC staining patterns.

  14. Image processing in digital pathology: an opportunity to solve inter-batch variability of immunohistochemical staining

    Science.gov (United States)

    Van Eycke, Yves-Rémi; Allard, Justine; Salmon, Isabelle; Debeir, Olivier; Decaestecker, Christine

    2017-01-01

    Immunohistochemistry (IHC) is a widely used technique in pathology to evidence protein expression in tissue samples. However, this staining technique is known for presenting inter-batch variations. Whole slide imaging in digital pathology offers a possibility to overcome this problem by means of image normalisation techniques. In the present paper we propose a methodology to objectively evaluate the need of image normalisation and to identify the best way to perform it. This methodology uses tissue microarray (TMA) materials and statistical analyses to evidence the possible variations occurring at colour and intensity levels as well as to evaluate the efficiency of image normalisation methods in correcting them. We applied our methodology to test different methods of image normalisation based on blind colour deconvolution that we adapted for IHC staining. These tests were carried out for different IHC experiments on different tissue types and targeting different proteins with different subcellular localisations. Our methodology enabled us to establish and to validate inter-batch normalization transforms which correct the non-relevant IHC staining variations. The normalised image series were then processed to extract coherent quantitative features characterising the IHC staining patterns. PMID:28220842

  15. Assessment of Seasonal and Annual Rainfall Trends and Variability in Sharjah City, UAE

    OpenAIRE

    Tarek Merabtene; Mohsin Siddique; Abdallah Shanableh

    2016-01-01

    Although a few studies on rainfall spatial and temporal variability in the UAE have been carried out, evidence of the impact of climate change on rainfall trends has not been reported. This study aims at assessing the significance of long-term rainfall trends and temporal variability at Sharjah City, UAE. Annual rainfall and seasonal rainfall extending over a period of 81 years (1934–2014) recorded at Sharjah International Airport have been analyzed. To this end, several parametric and nonpar...

  16. SU-E-J-176: Characterization of Inter-Fraction Breast Variability and the Implications On Delivered Dose

    Energy Technology Data Exchange (ETDEWEB)

    Sudhoff, M; Lamba, M; Kumar, N; Ward, A; Elson, H [University of Cincinnati, Cincinnati, OH (United States)

    2015-06-15

    Purpose: To systematically characterize inter-fraction breast variability and determine implications on delivered dose. Methods: Weekly port films were used to characterize breast setup variability. Five evenly spaced representative positions across the contour of each breast were chosen on the electronic port film in reference to graticule, and window and level was set such that the skin surface of the breast was visible. Measurements from the skin surface to treatment field edge were taken on each port film at each position and compared to the planning DRR, quantifying the variability. The systematic measurement technique was repeated for all port films for 20 recently treated breast cancer patients. Measured setup variability for each patient was modeled as a normal distribution. The distribution was randomly sampled from the model and applied as isocentric shifts in the treatment planning computer, representing setup variability for each fraction. Dose was calculated for each shifted fraction and summed to obtain DVHs and BEDs that modeled the dose with daily setup variability. Patients were categorized in to relevant groupings that were chosen to investigate the rigorousness of immobilization types, treatment techniques, and inherent anatomical difficulties. Mean position differences and dosimetric differences were evaluated between planned and delivered doses. Results: The setup variability was found to follow a normal distribution with mean position differences between the DRR and port film between − 8.6–3.5 mm with sigma range of 5.3–9.8 mm. Setup position was not found to be significantly different than zero. The mean seroma or whole breast PTV dosimetric difference, calculated as BED, ranged from a −0.23 to +1.13Gy. Conclusion: A systematic technique to quantify and model setup variability was used to calculate the dose in 20 breast cancer patients including variable setup. No statistically significant PTV or OAR BED differences were found between

  17. Mechanistic Physiologically Based Pharmacokinetic (PBPK) Model of the Heart Accounting for Inter-Individual Variability: Development and Performance Verification.

    Science.gov (United States)

    Tylutki, Zofia; Mendyk, Aleksander; Polak, Sebastian

    2018-04-01

    Modern model-based approaches to cardiac safety and efficacy assessment require accurate drug concentration-effect relationship establishment. Thus, knowledge of the active concentration of drugs in heart tissue is desirable along with inter-subject variability influence estimation. To that end, we developed a mechanistic physiologically based pharmacokinetic model of the heart. The models were described with literature-derived parameters and written in R, v.3.4.0. Five parameters were estimated. The model was fitted to amitriptyline and nortriptyline concentrations after an intravenous infusion of amitriptyline. The cardiac model consisted of 5 compartments representing the pericardial fluid, heart extracellular water, and epicardial intracellular, midmyocardial intracellular, and endocardial intracellular fluids. Drug cardiac metabolism, passive diffusion, active efflux, and uptake were included in the model as mechanisms involved in the drug disposition within the heart. The model accounted for inter-individual variability. The estimates of optimized parameters were within physiological ranges. The model performance was verified by simulating 5 clinical studies of amitriptyline intravenous infusion, and the simulated pharmacokinetic profiles agreed with clinical data. The results support the model feasibility. The proposed structure can be tested with the goal of improving the patient-specific model-based cardiac safety assessment and offers a framework for predicting cardiac concentrations of various xenobiotics. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  18. Cluster analysis and subgrouping to investigate inter-individual variability to non-invasive brain stimulation: a systematic review.

    Science.gov (United States)

    Pellegrini, Michael; Zoghi, Maryam; Jaberzadeh, Shapour

    2018-01-12

    Cluster analysis and other subgrouping techniques have risen in popularity in recent years in non-invasive brain stimulation research in the attempt to investigate the issue of inter-individual variability - the issue of why some individuals respond, as traditionally expected, to non-invasive brain stimulation protocols and others do not. Cluster analysis and subgrouping techniques have been used to categorise individuals, based on their response patterns, as responder or non-responders. There is, however, a lack of consensus and consistency on the most appropriate technique to use. This systematic review aimed to provide a systematic summary of the cluster analysis and subgrouping techniques used to date and suggest recommendations moving forward. Twenty studies were included that utilised subgrouping techniques, while seven of these additionally utilised cluster analysis techniques. The results of this systematic review appear to indicate that statistical cluster analysis techniques are effective in identifying subgroups of individuals based on response patterns to non-invasive brain stimulation. This systematic review also reports a lack of consensus amongst researchers on the most effective subgrouping technique and the criteria used to determine whether an individual is categorised as a responder or a non-responder. This systematic review provides a step-by-step guide to carrying out statistical cluster analyses and subgrouping techniques to provide a framework for analysis when developing further insights into the contributing factors of inter-individual variability in response to non-invasive brain stimulation.

  19. Residual Perchloroethylene in Dry-Cleaned Acetate: The Effect of Pressing and Extent of Inter-Dry-Cleaner Variability.

    Science.gov (United States)

    Brand, Kevin P; Jang, Christine J; Park, Ju-Hyeong; Serrano, Paulina I; Weker, Robert A; Lee, Kiyoung; Yanagisawa, Yukio

    1999-02-01

    Measurements of residual perchloroethylene (PCE), a dry-cleaning solvent associated with human health effects, were made in dry-cleaned acetate cloth to enable improved characterizations of both occupational and environmental exposure. A limited sample size (25 acetate cloths) was used to explore the extent of inter-dry-cleaner variability in residual PCE and to characterize the effect of the pressing operation on residual PCE. A new method, which uses carbon-disulfide as the direct extracting agent, proved effective in the analysis of residual PCE, with a recovery-efficiency ≈ 75%. Inter-dry-cleaner variability of residual PCE, although marginally statistically significant, was relatively low, showing only a fourfold range compared to a 5-order-of-magnitude range obtained from Kawauchi and Nishiyama 1 . Pairwise comparison of residual PCE in nonpressed versus pressed acetate samples revealed a statistically significant reduction (p < 0.008), which amounted to a consistent (among dry-cleaners) pressing-related removal efficiency of 75 ± 4%. A preliminary assessment of the source term associated with the pressing operation (mass PCE liberated per kg cloth dry-cleaned, S PCE ≈ 30 mg/kg) indicates a minor contribution to the average ambient air concentrations within dry-cleaning establishments.

  20. MRI assessment of tenosynovitis in children with juvenile idiopathic arthritis: inter- and intra-observer variability

    International Nuclear Information System (INIS)

    Lambot, Karen; Brunelle, Francis; Boavida, Peter; Damasio, Maria Beatrice; Tanturri de Horatio, Laura; Barbuti, Domenico; Desgranges, Marie; Bader-Meunier, Brigitte; Quartier, Pierre; Malattia, Clara; Bracaglia, Claudia; Ording Mueller, Lil-Sofie; Elie, Caroline; Rosendahl, Karen

    2013-01-01

    There is sparse knowledge about grading tenosynovitis using MRI. The purpose of this study was to assess the reliability of a tenosynovitis MRI scoring system in juvenile idiopathic arthritis. Children with juvenile idiopathic arthritis and wrist involvement were enrolled in two paediatric centres, from October 2006 to January 2010. The extensor (compartments II, IV and VI) and flexor tendons were assessed for the presence of tenosynovitis on T1-weighted postcontrast fat-saturated MR images and were scored from 0 (normal) to 2 (moderate to severe) by two observers independently. Intra- and interobserver agreement was assessed. Ninety children (age range: 5-18.5 years) were included, of whom 34 had tenosynovitis involving extensors and 28 had tenosynovitis involving flexors. A total of 360 tendon areas were analysed, of which 114 had tenosynovitis (86/270 extensors and 28/90 flexors). Intra-reader 1 agreement was excellent for the extensors (k = 0.82-0.91) and for the flexors (k = 0.85); intra-reader 2 agreement was moderate to good for the extensors (k = 0.51-0.72) and good for the flexors (k = 0.64). Inter-reader agreement was good for the extensors (k = 0.69-0.73) and moderate for the flexors (k = 0.49). The proposed MRI scoring system for the assessment of wrist tenosynovitis in juvenile idiopathic arthritis appears feasible with an observer agreement sufficient for clinical use. (orig.)

  1. MRI assessment of tenosynovitis in children with juvenile idiopathic arthritis: inter- and intra-observer variability

    Energy Technology Data Exchange (ETDEWEB)

    Lambot, Karen; Brunelle, Francis [Hopital Necker-Enfants Malades, Department of Paediatric Radiology, Paris (France); Boavida, Peter [Great Ormond Street Hospital, Department of Radiology, London (United Kingdom); Damasio, Maria Beatrice [Ospedale Pediatrico Gaslini, Department of Radiology, Genoa (Italy); Tanturri de Horatio, Laura; Barbuti, Domenico [Ospedale Pediatrico Bambino Gesu, Department of Radiology, Rome (Italy); Desgranges, Marie; Bader-Meunier, Brigitte; Quartier, Pierre [Hopital Necker-Enfants Malades, Department of Paediatric Immunology, Hematology and Rheumatology, APHP French Reference Center ' ' Arthrites juveniles' ' , Paris (France); Malattia, Clara [University of Genoa, Department of Paediatrics, Genoa (Italy); Bracaglia, Claudia [Ospedale Pediatrico Bambino Gesu, Department of Paediatrics, Rome (Italy); Ording Mueller, Lil-Sofie [Great Ormond Street Hospital, Department of Radiology, London (United Kingdom); University Hospital of North Norway, Department of Radiology, Tromsoe (Norway); Elie, Caroline [Paris Descartes University, Department of Biostatistics, Hopital Necker-Enfants Malades, Paris (France); Rosendahl, Karen [Great Ormond Street Hospital, Department of Radiology, London (United Kingdom); Haukeland University Hospital, Department of Radiology, Bergen (Norway)

    2013-07-15

    There is sparse knowledge about grading tenosynovitis using MRI. The purpose of this study was to assess the reliability of a tenosynovitis MRI scoring system in juvenile idiopathic arthritis. Children with juvenile idiopathic arthritis and wrist involvement were enrolled in two paediatric centres, from October 2006 to January 2010. The extensor (compartments II, IV and VI) and flexor tendons were assessed for the presence of tenosynovitis on T1-weighted postcontrast fat-saturated MR images and were scored from 0 (normal) to 2 (moderate to severe) by two observers independently. Intra- and interobserver agreement was assessed. Ninety children (age range: 5-18.5 years) were included, of whom 34 had tenosynovitis involving extensors and 28 had tenosynovitis involving flexors. A total of 360 tendon areas were analysed, of which 114 had tenosynovitis (86/270 extensors and 28/90 flexors). Intra-reader 1 agreement was excellent for the extensors (k = 0.82-0.91) and for the flexors (k = 0.85); intra-reader 2 agreement was moderate to good for the extensors (k = 0.51-0.72) and good for the flexors (k = 0.64). Inter-reader agreement was good for the extensors (k = 0.69-0.73) and moderate for the flexors (k = 0.49). The proposed MRI scoring system for the assessment of wrist tenosynovitis in juvenile idiopathic arthritis appears feasible with an observer agreement sufficient for clinical use. (orig.)

  2. Microarray estimation of genomic inter-strain variability in the genus Ectocarpus (Phaeophyceae

    Directory of Open Access Journals (Sweden)

    Peters Akira F

    2011-01-01

    Full Text Available Background Brown algae of the genus Ectocarpus exhibit high levels of genetic diversity and variability in morphological and physiological characteristics. With the establishment of E. siliculosus as a model and the availability of a complete genome sequence, it is now of interest to analyze variability among different species, ecotypes, and strains of the genus Ectocarpus both at the genome and the transcriptome level. Results We used an E. siliculosus gene expression microarray based on EST sequences from the genome-sequenced strain (reference strain to carry out comparative genome hybridizations for five Ectocarpus strains: four E. siliculosus isolates (the male genome strain, a female strain used for outcrosses with the genome strain, a strain isolated from freshwater, and a highly copper-tolerant strain, as well as one strain of the sister species E. fasciculatus. Our results revealed significant genomic differences between ecotypes of the same species, and enable the selection of conserved probes for future microarray experiments with these strains. In the two closely related strains (a male and a female strain used for crosses, genomic differences were also detected, but concentrated in two smaller genomic regions, one of which corresponds to a viral insertion site. Conclusion The high variability between strains supports the concept of E. siliculosus as a complex of cryptic species. Moreover, our data suggest that several parts of the Ectocarpus genome may have evolved at different rates: high variability was detected particularly in transposable elements and fucoxanthin chlorophyll a/c binding proteins.

  3. Studies on inter-speaker variability in speech and its application in ...

    Indian Academy of Sciences (India)

    In this review article, we study the variability in the acoustic signal among different speakers enunciating the same sound. ...... search, etc., nevertheless, the computational costs are high. Therefore, there have ... generation but will also help in accounting for the Jacobian of the transformation which is dis- cussed later in this ...

  4. Variability of inter-team distances associated with match events in elite-standard soccer

    NARCIS (Netherlands)

    Frencken, Wouter; De Poel, Harjo; Visscher, Chris; Lemmink, Koen

    2012-01-01

    In soccer, critical match events like goal attempts can be preceded by periods of instability in the balance between the two teams' behaviours. Therefore, we determined periods of high variability in the distance between the teams' centroid positions longitudinally and laterally in an

  5. Response of riparian vegetation across Australia's largest river basin to inter and intra-annual flooding: dynamics quantified from time series of Landsat and MODIS data

    Science.gov (United States)

    Broich, M.; Tulbure, M. G.; Keith, D.; Kingsford, R.; Lucas, R.; Lippmann, T.

    2014-12-01

    Australia is a continent subject to high rainfall variability. The resulting spatial-temporal pattern of flooding and its influence on riparian vegetation has not been quantified. Here we focused on the floodplains of the entire Murray-Darling Basin (MDB; 72 Landsat path-rows) of Australia as a case study. The MDB is the country's primary agricultural area with scarce water resources impacted by climate change and extensive zones with degrading riparian vegetation. We advance our understanding of the relationship between climate-driven flooding dynamics and vegetation response at the sub-continental to local and inter to intra-annual scale based on two decades of Landsat and one decade of MODIS imagery. We Landsat TM and ETM+ data to synoptically map spatially detailed dynamics of flooding with an internally consistent machine learning algorithm. We derived riparian phenology (Fig 1) from MODIS data and attributed differences in vegetation response to flooding dynamics, vegetation types and sub-basin land use. Vegetation community response to flooding varied in space and time and with vegetation types, densities and location relative to areas frequently flooded. Phenological degradation trends were observed over riparian forests and woodlands in the middle and lower parts of the basin that are primarily farmed and were we identified flooding regimes to have changed the most to less frequent and smaller inundation extents. Conversely, herbaceous vegetation phenology followed primarily a boom and bust cycle related to less extensive flooding dynamics. This pattern was found across different areas of the basin. As expected, flooding regimes and vegetation response patterns were fine grained confirming the choice of a spatially explicit, internally consistent analysis leading the path for ongoing monitoring. Remote sensing-based monitoring of the response of riparian vegetation to flooding can be used to quantify spatially explicit changes in vegetation community

  6. Intra- and Inter-Patient Symptom Variability in Fibromyalgia: Results of a 90-Day Assessment.

    Science.gov (United States)

    Toussaint, Loren; Vincent, Ann; McAllister, Samantha J; Whipple, Mary

    2015-06-01

    Symptoms of fibromyalgia (FM)--chronic widespread pain, fatigue, unrefreshing sleep, dyscognition etcetera--present with varying degrees of severity in different individuals; however, studies reporting daily estimates of variability of symptoms are sparse. Given the limited literature on the stability and variability of FM symptoms, the purpose of the present study was to determine the feasibility of daily visual analogue, self-report measures to assess daily variability and time trends in core FM symptoms. Ten female patients completed daily assessments of common FM symptoms (pain, fatigue, anxiety, depression, stress, cognitive dysfunction, unrefreshing sleep and lightheadedness) for approximately 90 days. The completion rate was excellent (89.6%). The results demonstrated that average symptom intensity differs markedly across the different symptoms that were measured. Unrefreshing sleep, fatigue and pain are clearly higher in intensity than other symptoms and are followed by memory problems, stress, anxiety and depression. There is also notable average intra-individual change across time (10-15 points on a 100-point scale). Average symptom intensity does not appear to be related to the amount of symptom change within individuals. The results of the present study confirm that intensive longitudinal study, using comprehensive symptom assessment in patients with FM, is both possible and informative, in the sense that a rich description of the daily experience of living with FM can be obtained. Future work, utilizing larger samples, will offer the opportunity to investigate better the causes, consequences and correlates of the daily ups and downs of key symptoms that compromise quality of life in patients with FM. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Inter-Individual Variability of Stone Marten Behavioral Responses to a Highway

    Science.gov (United States)

    Ascensão, Fernando; Grilo, Clara; LaPoint, Scott; Tracey, Jeff; Clevenger, Anthony P.; Santos-Reis, Margarida

    2014-01-01

    Efforts to reduce the negative impacts of roads on wildlife may be hindered if individuals within the population vary widely in their responses to roads and mitigation strategies ignore this variability. This knowledge is particularly important for medium-sized carnivores as they are vulnerable to road mortality, while also known to use available road passages (e.g., drainage culverts) for safely crossing highways. Our goal in this study was to assess whether this apparently contradictory pattern of high road-kill numbers associated with a regular use of road passages is attributable to the variation in behavioral responses toward the highway between individuals. We investigated the responses of seven radio-tracked stone martens (Martes foina) to a highway by measuring their utilization distribution, response turning angles and highway crossing patterns. We compared the observed responses to simulated movement parameterized by the observed space use and movement characteristics of each individual, but naïve to the presence of the highway. Our results suggested that martens demonstrate a diversity of responses to the highway, including attraction, indifference, or avoidance. Martens also varied in their highway crossing patterns, with some crossing repeatedly at the same location (often coincident with highway passages). We suspect that the response variability derives from the individual's familiarity of the landscape, including their awareness of highway passage locations. Because of these variable yet potentially attributable responses, we support the use of exclusionary fencing to guide transient (e.g., dispersers) individuals to existing passages to reduce the road-kill risk. PMID:25072639

  8. Long-term phenology and variability of Southern Africa

    CSIR Research Space (South Africa)

    Steenkamp, K

    2008-11-01

    Full Text Available southern Africa in order to investigate which phenometrics (and their inter-annual variability) distinguish biomes based on functional patterns. A second objective was to quantify the inter-annual variability of phenometrics during a 15-year period (1985...

  9. Description, evaluation and clinical decision making according to various fetal heart rate patterns. Inter-observer and regional variability

    DEFF Research Database (Denmark)

    Lidegaard, O; Bøttcher, L M; Weber, Tom

    1992-01-01

    departments, especially between departments far apart. It is concluded that we still need a scientific clarification of which specific heart rate changes are the best predictors of fetal stress. Artificial intelligence programs for interpreting fetal cardiotocograms and ECG signals constitute one promising......At 10 Danish obstetrical departments, 116 residents (42 senior and 74 junior) participated in a study to assess inter-observer and regional variability in the description and evaluation of and clinical decision regarding 11 fetal heart rate patterns. The 11 traces included normal as well...... as pathological patterns, and normal as well as clinically asphyxiated babies. Five antepartum and six intrapartum patterns were included. A total of 1,276 descriptions and evaluations were obtained. The degree of agreement in description of fetal heart rate changes was high regarding the baseline...

  10. Inter-labeler and intra-labeler variability of condition severity classification models using active and passive learning methods.

    Science.gov (United States)

    Nissim, Nir; Shahar, Yuval; Elovici, Yuval; Hripcsak, George; Moskovitch, Robert

    2017-09-01

    Labeling instances by domain experts for classification is often time consuming and expensive. To reduce such labeling efforts, we had proposed the application of active learning (AL) methods, introduced our CAESAR-ALE framework for classifying the severity of clinical conditions, and shown its significant reduction of labeling efforts. The use of any of three AL methods (one well known [SVM-Margin], and two that we introduced [Exploitation and Combination_XA]) significantly reduced (by 48% to 64%) condition labeling efforts, compared to standard passive (random instance-selection) SVM learning. Furthermore, our new AL methods achieved maximal accuracy using 12% fewer labeled cases than the SVM-Margin AL method. However, because labelers have varying levels of expertise, a major issue associated with learning methods, and AL methods in particular, is how to best to use the labeling provided by a committee of labelers. First, we wanted to know, based on the labelers' learning curves, whether using AL methods (versus standard passive learning methods) has an effect on the Intra-labeler variability (within the learning curve of each labeler) and inter-labeler variability (among the learning curves of different labelers). Then, we wanted to examine the effect of learning (either passively or actively) from the labels created by the majority consensus of a group of labelers. We used our CAESAR-ALE framework for classifying the severity of clinical conditions, the three AL methods and the passive learning method, as mentioned above, to induce the classifications models. We used a dataset of 516 clinical conditions and their severity labeling, represented by features aggregated from the medical records of 1.9 million patients treated at Columbia University Medical Center. We analyzed the variance of the classification performance within (intra-labeler), and especially among (inter-labeler) the classification models that were induced by using the labels provided by seven

  11. SU-F-J-103: Assessment of Liver Tumor Contrast for Radiation Therapy: Inter-Patient and Inter-Sequence Variability

    International Nuclear Information System (INIS)

    Moore, B; Yin, F; Cai, J; Czito, B; Palta, M

    2016-01-01

    Purpose: To determine the variation in tumor contrast between different MRI sequences and between patients for the purpose of MRI-based treatment planning. Methods: Multiple MRI scans of 11 patients with cancer(s) in the liver were included in this IRB-approved study. Imaging sequences consisted of T1W MRI, Contrast-Enhanced T1W MRI, T2W MRI, and T2*/T1W MRI. MRI images were acquired on a 1.5T GE Signa scanner with a four-channel torso coil. We calculated the tumor-to-tissue contrast to noise ratio (CNR) for each MR sequence by contouring the tumor and a region of interest (ROI) in a homogeneous region of the liver using the Eclipse treatment planning software. CNR was calculated (I_Tum-I_ROI)/SD_ROI, where I_Tum and I_ROI are the mean values of the tumor and the ROI respectively, and SD_ROI is the standard deviation of the ROI. The same tumor and ROI structures were used in all measurements for different MR sequences. Inter-patient Coefficient of variation (CV), and inter-sequence CV was determined. In addition, mean and standard deviation of CNR were calculated and compared between different MR sequences. Results: Our preliminary results showed large inter-patient CV (range: 37.7% to 88%) and inter-sequence CV (range 5.3% to 104.9%) of liver tumor CNR, indicating great variations in tumor CNR between MR sequences and between patients. Tumor CNR was found to be largest in CE-T1W (8.5±7.5), followed by T2W (4.2±2.4), T1W (3.4±2.2), and T2*/T1W (1.7±0.6) MR scans. The inter-patient CV of tumor CNR was also the largest in CE-T1W (88%), followed by T1W (64.3%), T1W (56.2%), and T2*/T1W (37.7) MR scans. Conclusion: Large inter-sequence and inter-patient variations were observed in liver tumor CNR. CE-T1W MR images on average provided the best tumor CNR. Efforts are needed to optimize tumor contrast and its consistency for MRI-based treatment planning of cancer in the liver. This project is supported by NIH grant: 1R21CA165384

  12. Demandas de urgencias clínicas: Algunas variables de interés

    Directory of Open Access Journals (Sweden)

    Javier Pereda Rodríguez

    2001-08-01

    Full Text Available Resumen Se realizó un estudio descriptivo analítico de la demanda asistencial en el área de medicina interna de los Servicios de Urgencia, en el Hospital "Dr. Luis Díaz Soto" y el Policlínico "Dr. Mario Escalona Reguera", durante el período comprendido entre las 8:00 h del día 29/5/95 y las 7:59 h del 3/6/95. Con el objetivo de conocer el comportamiento de la demanda se estudió su distribución en cuanto a edad, sexo, grupos horarios (laboral y extralaboral y días de la semana. Se concluyó que no existe asociación estadística entre la edad y el sexo, según la distribución de la demanda, no así entre las otras variables y los grupos horarios, donde se observaron diferencias altamente significativas con un predominio de pacientes en edades jóvenes que asistían principalmente durante el horario laboral. El día de mayor carga de trabajo fue el lunes.Summary A descriptive analytic study of the assistance demand in the area of internal medicine of the Emergency Service of "Dr. Luis Díaz Soto" Hospital and of "Dr. Mario Escalona Reguera" Polyclinic was conducted from May 29th, 1995, at 8 a.m., to June 3rd, 1995, at 7:59 a.m. In order to know the behaviour of the demand its distribution was studied taking into account age, sex, horary groups (working and nonworking hours and days of the week. It was concluded that there is no statistical association between age and sex, according to the demand distribution. However, highly significant differences were observed between the other variables and the horary groups. There was a predominance of young patients, who were attended mainly during the working hours. Monday was the day with the greatest working load.

  13. Variabilidade interensaios de dislipidemias em pacientes hipertensos Inter-assays variability of dislipidemias in hypertensive patients

    Directory of Open Access Journals (Sweden)

    Nilton Rosini

    2009-08-01

    hipolipemiantes a serem adotadas.INTRODUCTION AND OBJECTIVES: Different assays to evaluate dyslipidemia may show significant variations in the obtained results and a consequent inappropriate clinical approach may be adopted. This study aimed to compare the results of total cholesterol (CT, triglycerides (TG, HDL-C, Apo A1, Apo B, lipoprotein (a and lipidic indexes (not-HDL-C, CT/HDL-C, LDL-C/HDL-C, TG/HDL-C and Apo B/HDL-C of hypertensive and/or diabetic patients. METHODS: The following reactive kits and respective analyzers were applied to verify the reproducibility of results: Gold Analisa, DiaSys (CCX-ABBOTT, Dade Behring (Nephelometer BN 100 and Roche (COBAS Integra 400. Ninety nine patients (36 male and 63 female gender were investigated. Comparing the results, we observed that all mean numbers of lipid constituents showed a significant difference. A similar number of patients had high CT, TG, Lp (a and Apo A-1 serum levels. There was also disagreement in HDL-C, LDL-C, ApoB, CT/LDL-C, LDL-C/HDL-C and TG/HDL-C indexes. For not-HDL-C and ApoB/HDL, there was similarity in the number of patients with not recommended values. As a consequence of this difference, the choice of therapeutic approach may be inappropriate as to LDL-C levels, whereas Not-HDL-C not only showed atherogenic particles but also a number of hypertensive patients with similar not recommended serum values, regardless of the methodology and the equipment used. CONCLUSION: In the analyzed group of hypertensive patients, not-HDL-C was an important inter assay correction factor of lipidic parameters. The association with Apo B/HDL-C relation may be an additional factor as to the choice of hypolipemiant treatments.

  14. Inter-individual variability of plasma PAF-acetylhydrolase activity in ARDS patients and PAFAH genotype.

    Science.gov (United States)

    Li, S; Stuart, L; Zhang, Y; Meduri, G U; Umberger, R; Yates, C R

    2009-08-01

    Platelet activating factor (PAF), a pro-inflammatory phospholipid, stimulates cytokine secretion from polymorphonuclear leukocytes expressing the transmembrane G-protein coupled PAF receptor. Elevated PAF levels are associated with acute respiratory distress syndrome (ARDS) and sepsis severity. The pro-inflammatory effects of PAF are terminated by PAF acetylhydrolase (PAF-AH). We sought to determine whether allelic variants in the human PAFAH gene (Arg92His, Ile198Thr, and Ala379Val) contribute to variability in PAF-AH activity in patient plasma obtained within 72 h of ARDS diagnosis. Plasma PAF-AH activity (mean +/- SD) was higher in patients homozygous for the Arg92 allele compared to His92 allele carriers (2.21 +/- 0.77 vs. 1.64 +/- 0.68 U/min; P PAF-AH activity was higher among day 7 survivors vs. day 7 non-survivors (2.05 +/- 0.75 vs. 1.27 +/- 0.63, P = 0.05). These data demonstrate an association between PAF-AH allelic variation, plasma activity, and outcome in ARDS.

  15. Karyotype Variability and Inter-Population Genomic Differences in Freshwater Ostracods (Crustacea Showing Geographical Parthenogenesis

    Directory of Open Access Journals (Sweden)

    Radka Symonová

    2018-03-01

    Full Text Available Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820, where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH within and among sexual and asexual populations to get insights into E. virens genome arrangements. CGH disclosed substantial genomic imbalances among the populations analyzed, and three patterns of genome arrangement between these populations: 1. Only putative ribosomal DNA (rDNA-bearing regions were conserved in the two populations compared indicating a high sequence divergence between these populations. This pattern is comparable with our findings at the interspecies level of comparison; 2. Chromosomal regions were shared by both populations to a varying extent with a distinct copy number variation in pericentromeric and presumable rDNA-bearing regions. This indicates a different rate of evolution in repetitive sequences; 3. A mosaic pattern of distribution of genomic material that can be explained as non-reciprocal genetic introgression and evidence of a hybrid origin of these individuals. We show an overall increased chromosomal dynamics in E. virens that is complementary with available phylogenetic and population genetic data reporting highly differentiated diploid sexual and asexual lineages with a wide variety of genetic backgrounds.

  16. An analysis of factors associated with influenza, pneumoccocal, Tdap, and herpes zoster vaccine uptake in the US adult population and corresponding inter-state variability.

    Science.gov (United States)

    La, Elizabeth M; Trantham, Laurel; Kurosky, Samantha K; Odom, Dawn; Aris, Emmanuel; Hogea, Cosmina

    2018-02-01

    Despite longstanding recommendations for routine vaccination against influenza; pneumococcal; tetanus, diphtheria, acellular pertussis (Tdap); and herpes zoster (HZ) among the United States general adult population, vaccine uptake remains low. Understanding factors that influence adult vaccination and coverage variability beyond the national level are important steps toward developing targeted strategies for increasing vaccination coverage. A retrospective analysis was conducted using data from the Behavioral Risk Factor Surveillance System (2011-2014). Multivariable logistic regression modeling was employed to identify individual factors associated with vaccination (socio-demographics, health status, healthcare utilization, state of residence) and generate adjusted vaccination coverage and compliance estimates nationally and by state. Results indicated that multiple characteristics were consistently associated with a higher likelihood of vaccination across all four vaccines, including female sex, increased educational attainment, and annual household income. Model-adjusted vaccination coverage estimates varied widely by state, with inter-state variability for the most recent year of data as follows: influenza (aged ≥18 years) 30.2-49.5%; pneumococcal (aged ≥65 years) 64.0-74.7%; Tdap (aged ≥18 years) 18.7-46.6%; and HZ (aged ≥60 years) 21.3-42.9%. Model-adjusted compliance with age-appropriate recommendations across vaccines was low and also varied by state: influenza+Tdap (aged 18-59 years) 7.9-24.7%; influenza+Tdap+HZ (aged 60-64 years) 4.1-14.4%; and influenza+Tdap+HZ+pneumococcal (aged ≥65 years) 3.0-18.3%. In summary, after adjusting for individual characteristics associated with vaccination, substantial heterogeneity across states remained, suggesting that other local factors (e.g. state policies) may be impacting adult vaccines uptake. Further research is needed to understand such factors, focusing on differences between states with high versus

  17. Differential responses of seabirds to inter-annual environmental change in the continental shelf and oceanic habitats of southeastern Bering Sea

    Science.gov (United States)

    Yamamoto, T.; Kokubun, N.; Kikuchi, D. M.; Sato, N.; Takahashi, A.; Will, A.; Kitaysky, A. S.; Watanuki, Y.

    2015-11-01

    Seasonal sea-ice cover has been decreasing in the southeastern Bering Sea shelf, which might affect ecosystem dynamics and availability of food resources to marine top predators breeding in the region. In this study, we investigated the foraging responses of two seabird species, surface-foraging red-legged kittiwakes Rissa brevirostris (hereafter, RLKI) and pursuit-diving foraging thick-billed murres Uria lomvia (TBMU) to the inter-annual change in environmental conditions. Between the study years, winter ice retreated earlier and summer water temperatures were warmer in 2014 compared to those in 2013. At-sea distributions of RLKI and TBMU breeding on St. George Island, the largest seabird colony in the region, were recorded using GPS loggers, and blood samples were taken to examine their physiological condition and isotopic foraging niche in a given year. RLKI foraging occurred mostly over the oceanic basin in both years. TBMU, however, foraged mostly over the shelf, but showed a relatively higher use of the shelf break and oceanic basin in the colder year, 2013. The foraging distances from the colony peaked at 250-300 km in 2013 and, bimodally, at 150-250 and 300-350 km in 2014 for RLKI, and tended to be farther in 2013 compared to those in 2014 for TBMU. Plasma levels of corticosterone did not differ between years in RLKI, but differed in TBMU, showing higher levels of physiological stress incurred by murres during the colder year, 2013. δ13N (a proxy of trophic level of prey) did not differ between the years in either RLKI or TBMU, while δ13C (a proxy of prey origin) were lower in 2014 than in 2013 in both species, suggesting possible differences in influx of oceanic prey items into foraging areas. These results suggest that the response of ecosystem dynamics to climate variability in the southeast Bering Sea may differ between the ocean basin and continental shelf regions, which, in turn, may generate differential responses in seabirds relying on those

  18. Abnormalities of the airways and lung parenchyma in asthmatics: CT observations in 50 patients and inter- and intraobserver variability

    International Nuclear Information System (INIS)

    Grenier, P.; Mourey-Gerosa, I.; Benali, K.; Brauner, M.W.; Leung, A.N.; Lenoir, S..; Cordeau, M.P.; Mazoyer, B.

    1996-01-01

    The purpose of the study was to evaluate the CT abnormalities of airways and lung parenchyma in asthmatic patients and to assess inter- and intraobserver variability for these abnormalities. The CT scans of 50 asthmatic patients and 10 healthy volunteers were assessed independently by four independent chest radiologists who were masked with respect to the clinical informations. Bronchiectasis involving mostly subsegmental and destal bronchi was noted in 28.5% of the asthmatic subjects and none of the non-asthmatics. Bronchial wall thickening, small centrilobular opacities and decreased lung attenuation were observed in 82%, 21% and 31% of asthmatic patients respectively, compared with 7%, 5% and 7% of healthy subjects. The intra- and interobserver agreements for these four CT abnormalities were measured by the kappa statistic and ranged from 0.60 to 0.79 and from 0.40 to 0.64, respectively. It is concluded that asthmatic patients may exhibit bronchial wall thickening, bronchiectasis and morphological abnormalities suggestive of distal airways disease that can be assessed on CT scans with a clinically acceptable observer variability. (orig.)

  19. Absorption, Metabolism and Excretion of Cranberry (Polyphenols in Humans: A Dose Response Study and Assessment of Inter-Individual Variability

    Directory of Open Access Journals (Sweden)

    Rodrigo P. Feliciano

    2017-03-01

    Full Text Available The beneficial health effects of cranberries have been attributed to their (polyphenol content. Recent studies have investigated the absorption, metabolism and excretion of cranberry (polyphenols; however, little is known about whether they follow a dose response in vivo at different levels of intake. An acute double-blind randomized controlled trial in 10 healthy men with cranberry juices containing 409, 787, 1238, 1534 and 1910 mg total (polyphenols was performed. Blood and urine were analyzed by UPLC-Q-TOF-MS. Sixty metabolites were identified in plasma and urine including cinnamic acids, dihydrocinnamic, flavonols, benzoic acids, phenylacetic acids, benzaldehydes, valerolactones, hippuric acids, catechols, and pyrogallols. Total plasma, but not excreted urinary (polyphenol metabolites, exhibited a linear dose response (r2 = 0.74, p < 0.05, driven by caffeic acid 4-O-ß-d-glucuronide, quercetin-3-O-ß-d-glucuronide, ferulic acid 4-O-ß-d-glucuronide, 2,5-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, ferulic acid, caffeic acid 3-O-ß-d-glucuronide, sinapic acid, ferulic acid 4-O-sulfate, 3-hydroxybenzoic acid, syringic acid, vanillic acid-4-O-sulfate, (4R-5-(3′-hydroxyphenyl-γ-valerolactone-4′-O-sulfate, 4-methylgallic acid-3-O-sulfate, and isoferulic acid 3-O-sulfate (all r2 ≥ 0.89, p < 0.05. Inter-individual variability of the plasma metabolite concentration was broad and dependent on the metabolite. Herein, we show that specific plasma (polyphenol metabolites are linearly related to the amount of (polyphenols consumed in cranberry juice. The large inter-individual variation in metabolite profile may be due to variations in the gut microbiome.

  20. Coryneform bacteria in human semen: inter-assay variability in species composition detection and biofilm production ability

    Directory of Open Access Journals (Sweden)

    Silver Türk

    2014-02-01

    Full Text Available Background: Coryneform bacteria constitute an important segment of male urogenital microbiota. They have been generally considered as saprophytes, although some species have been associated with prostatitis as well. At the same time, biofilm infections have been suspected as a cause of prostatitis. Objective: To identify a set of coryneform bacteria isolated from semen of either healthy men or prostatitis patients applying different methods to reveal inter-assay variability and to determine their ability of adhesion and biofilm production. Design: Coryneform bacteria were identified by API Coryne 2.0 biochemical identification system and 16S rDNA sequencing using different primer sets. Quantitative assessment of biofilm production was performed using crystal violet binding assay method. Results: The most common species were Corynebacterium seminale, C. minutissimum, and Dermabacter hominis. Altogether 14 species and related genera were found. We observed the best inter-assay agreement when identifying C. seminale. Biofilm was observed in 7 out of 24 strains. The biofilm-producing strains belonged to Arthrobacter cumminsii, Dermabacter hominis, C. minutissimum, and Actinomyces neuii. No differences were found between the strains originating from prostatitis patients and healthy men. Dermabacter hominis strains were more potent biofilm producers than C. seminale strains (p=0.048. Conclusions: We can conclude that a wide variety of coryneform bacteria can be found from the male genital tract, although their exact identification is problematic due to insufficient representation in databases. Nearly one third of the strains are able to form biofilm that may give them an advantage for surviving several host- and treatment-related conditions.

  1. Assessment of Seasonal and Annual Rainfall Trends and Variability in Sharjah City, UAE

    Directory of Open Access Journals (Sweden)

    Tarek Merabtene

    2016-01-01

    Full Text Available Although a few studies on rainfall spatial and temporal variability in the UAE have been carried out, evidence of the impact of climate change on rainfall trends has not been reported. This study aims at assessing the significance of long-term rainfall trends and temporal variability at Sharjah City, UAE. Annual rainfall and seasonal rainfall extending over a period of 81 years (1934–2014 recorded at Sharjah International Airport have been analyzed. To this end, several parametric and nonparametric statistical measures have been applied following systematic data quality assessment. The analyses revealed that the annual rainfall trend decreased from −3 mm to −9.4 mm per decade over the study periods. The decreasing annual rainfall trend is mainly driven by the significant drop in winter rainfall, particularly during the period from 1977 to 2014. The results also indicate that high probability extreme events have shifted toward low frequency (12.7 years with significant variations in monthly rainfall patterns and periodicity. The findings of the present study suggest reevaluating the derivation of design rainfall for infrastructure of Sharjah City and urge developing an integrated framework for its water resources planning and risk under climate change impacts scenarios.

  2. Climate effects on inter- and intra-annual larch stemwood anomalies in the Mongolian forest-steppe

    Science.gov (United States)

    Khishigjargal, Mookhor; Dulamsuren, Choimaa; Leuschner, Hanns Hubert; Leuschner, Christoph; Hauck, Markus

    2014-02-01

    Climate response of tree-ring width and intra-annual wood anomalies were studied in stands of Siberian larch (Larix sibirica) on Mt. Bogd Uul in the forest-steppe ecotone of Mongolia. Climate on Mt. Bogd Uul is characterized by an increase of the annual mean temperature by 1.5 K between 1965 and 2007, the lack of a long-term trend for annual precipitation and, with it, an increase in aridity. Tree-ring width increases with increasing June precipitation of the current year (June) and increasing late summer precipitation of the previous year. In >100-year old trees, also a negative correlation of tree-ring width with the July temperature of the year prior to tree-ring formation was found. Decreasing tree-ring width with increasing snowfall in December can be explained with the protection of the frost-sensitive eggs of gypsy moth by snow cover, which is a major herbivore of larch in Mongolia and causes reduction in the annual stem increment. The most significant change in wood anatomy was the decline of wide latewood, which is attributable to the increase of summer days with a mean temperature > 15 °C and drought periods in summer without precipitation. Increasing summer drought is also thought to have caused the repeated occurrence of missing rings since the 1960s, which were not observed in the late 19th and early 20th centuries.

  3. Annual and interannual variability of forest fires in South America and their temporal scaling in Amazonia

    International Nuclear Information System (INIS)

    Becerra Romero, Alejandro; Poveda, German

    2006-01-01

    Investigating the dynamics of forest fires in time is a challenge for environmental sciences, due to their close relation to land use and land change and their connections with the earth's climate through land surface-atmosphere feedbacks, as well as interannual variability associated with ENSO. By means of the ATSR world fire atlas data set (ESA, Europe), pertaining to the GOFC/GOLD-Fire program (monitoring and mapping implementation team), we quantify the annual and interannual variability of forest fires in South America (in three zones: Amazonia, river of La Plata and Colombo Venezuelan plain) on annual and interannual time scales, and the properties of temporary scaling of registered forest fires in the river basin of the Amazon River are quantified for the period 1997-2003. The fires in South America exhibit a noticeable annual cycle that is associated with the annual cycle of precipitations in each zone of study. The effect of the two phases of phenomenon ENSO is demonstrated, with greater fire incidence during El Nino and diminution during La Nina. The power law that relates the area to the fire frequency (fire surface versus number of events) exhibits three zones of scaling such that fires of 1 km 2 or less (θ = 0,4253, R 2 0,9701), between 1 - 20 km 2 θ - 1,1972, R 2 = 0,9893), and between 20 km 2 - 232 km 2 (θ = 2,7354, R 2 - 0,9396). The results reveal that the temporary evolution of forest fires in a site can be modeled like a fractal process of long-term memory, with exponents of scaling between 2,199 (log time vr log factor Fano (t) and 2,2476 (Log Time vr log factor Allan (t)

  4. Air-Sea CO2 fluxes on the Scotian Shelf: seasonal to multi-annual variability

    Directory of Open Access Journals (Sweden)

    J. E. Salisbury

    2010-11-01

    Full Text Available We develop an algorithm to compute pCO2 in the Scotian Shelf region (NW Atlantic from satellite-based estimates of chlorophyll-a concentration, sea-surface temperature, and observed wind speed. This algorithm is based on a high-resolution time-series of pCO2 observations from an autonomous mooring. At the mooring location (44.3° N and 63.3° W, the surface waters act as a source of CO2 to the atmosphere over the annual scale, with an outgassing of −1.1 mol C m−2 yr−1 in 2007/2008. A hindcast of air-sea CO2 fluxes from 1999 to 2008 reveals significant variability both spatially and from year to year. Over the decade, the shelf-wide annual air-sea fluxes range from an outgassing of −1.70 mol C m−2 yr−1 in 2002, to −0.02 mol C m−2 yr−1 in 2006. There is a gradient in the air-sea CO2 flux between the northeastern Cabot Strait region which acts as a net sink of CO2 with an annual uptake of 0.50 to 1.00 mol C m−2 yr−1, and the southwestern Gulf of Maine region which acts as a source ranging from −0.80 to −2.50 mol C m−2 yr−1. There is a decline, or a negative trend, in the air-sea pCO2 gradient of 23 μatm over the decade, which can be explained by a cooling of 1.3 °C over the same period. Regional conditions govern spatial, seasonal, and interannual variability on the Scotian Shelf, while multi-annual trends appear to be influenced by larger scale processes.

  5. Inter-annual variation in the response of Pinus taeda tree growth to long term Free Air Carbon dioxide Enrichment (FACE)

    Science.gov (United States)

    Moore, D. J.; Aref, S.; Ho, R. M.; Pippen, J. S.; Hamilton, J.; de Lucia, E. H.

    2005-12-01

    Rising carbon dioxide is predicted to increase forest productivity, though the duration of the response and how it might be altered by annual variation in rainfall and temperature are not well understood. For eight years we measured the basal area of trees exposed to Free Air Carbon-dioxide Enrichment (FACE) in a rapidly growing Pinus taeda plantation and used these measurements to estimate monthly and annual growth. We coupled these measurements with a mathematical model to estimate the start and end of growth in each year. Elevated carbon dioxide increased the basal area increment (BAI) of trees by 13 to 27 percent. Exposure to elevated carbon dioxide increased the growth rate but not the duration of the growing season in most years. With the exception of one year following an extreme drought and a severe ice storm, BAI was positively correlated with the amount of rainfall during the growing season. The inter-annual variation in the relative enhancement of BAI caused by elevated carbon dioxide was strongly related to the combination of temperature and rainfall during the growing season. There was no evidence of a systematic reduction in the stimulation of growth during the first eight years of this experiment, suggesting that hypothesized limitation of the carbon dioxide response caused by nitrogen availability has yet to occur.

  6. Annual and interannual variability of scatterometer ocean surface wind over the South China Sea

    DEFF Research Database (Denmark)

    Zhang, GS; Xu, Q.; Gong, Z.

    2014-01-01

    To investigate the annual and interannual variability of ocean surface wind over the South China Sea (SCS), the vector empirical orthogonal function (VEOF) method and the Hilbert-Huang transform (HHT) method were employed to analyze a set of combined satellite scatterometer wind data during...... the period from December 1992 to October 2009. The merged wind data were generated from European Remote Sensing Satellite (ERS)-1/2 Scatterometer, NASA Scatterometer (NSCAT) and NASA's Quick Scatterometer (QuikSCAT) wind products. The first VEOF mode corresponds to a winter-summer mode which accounts for 87...

  7. Three Ingredients for Improved Global Aftershock Forecasts: Tectonic Region, Time-Dependent Catalog Incompleteness, and Inter-Sequence Variability

    Science.gov (United States)

    Page, M. T.; Hardebeck, J.; Felzer, K. R.; Michael, A. J.; van der Elst, N.

    2015-12-01

    Following a large earthquake, seismic hazard can be orders of magnitude higher than the long-term average as a result of aftershock triggering. Due to this heightened hazard, there is a demand from emergency managers and the public for rapid, authoritative, and reliable aftershock forecasts. In the past, USGS aftershock forecasts following large, global earthquakes have been released on an ad-hoc basis with inconsistent methods, and in some cases, aftershock parameters adapted from California. To remedy this, we are currently developing an automated aftershock product that will generate more accurate forecasts based on the Reasenberg and Jones (Science, 1989) method. To better capture spatial variations in aftershock productivity and decay, we estimate regional aftershock parameters for sequences within the Garcia et al. (BSSA, 2012) tectonic regions. We find that regional variations for mean aftershock productivity exceed a factor of 10. The Reasenberg and Jones method combines modified-Omori aftershock decay, Utsu productivity scaling, and the Gutenberg-Richter magnitude distribution. We additionally account for a time-dependent magnitude of completeness following large events in the catalog. We generalize the Helmstetter et al. (2005) equation for short-term aftershock incompleteness and solve for incompleteness levels in the global NEIC catalog following large mainshocks. In addition to estimating average sequence parameters within regions, we quantify the inter-sequence parameter variability. This allows for a more complete quantification of the forecast uncertainties and Bayesian updating of the forecast as sequence-specific information becomes available.

  8. Inter- and intra-observer variability associated with the use of the Mirels' scoring system for metastatic bone lesions.

    LENUS (Irish Health Repository)

    Mac Niocaill, Ruairi F

    2011-01-01

    Metastatic bone disease is increasing in association with ever-improving medical management of osteophylic malignant conditions. The precise timing of surgical intervention for secondary lesions in long bones can be difficult to determine. This paper aims to evaluate a classic scoring system. All radiographs were examined twice by three orthopaedic oncologists and scored according to the Mirels\\' scoring system. The Kappa statistic was used for the purpose of statistical analysis. The results show agreement between observers (κ = 0.35-0.61) for overall scores at the two time intervals. Inter-observer agreement was also seen with subset analysis of size (κ = 0.27-0.60), site (κ = 0.77-1.0) and nature of the lesion (κ = 0.55-0.81). Similarly, low levels of intra-observer variability were noted for each of the three surgeons (κ= 0.34, 0.39, and 0.78, respectively). These results indicate a reliable, repeatable assessment of bony metastases. We continue to advocate its use in the management of patients with long bone metastases.

  9. Inter-observer variability in the classification of ovarian cancer cell type using microscopy: a pilot study

    Science.gov (United States)

    Gavrielides, Marios A.; Ronnett, Brigitte M.; Vang, Russell; Seidman, Jeffrey D.

    2015-03-01

    Studies have shown that different cell types of ovarian carcinoma have different molecular profiles, exhibit different behavior, and that patients could benefit from typespecific treatment. Different cell types display different histopathology features, and different criteria are used for each cell type classification. Inter-observer variability for the task of classifying ovarian cancer cell types is an under-examined area of research. This study served as a pilot study to quantify observer variability related to the classification of ovarian cancer cell types and to extract valuable data for designing a validation study of digital pathology (DP) for this task. Three observers with expertise in gynecologic pathology reviewed 114 cases of ovarian cancer with optical microscopy, with specific guidelines for classifications into distinct cell types. For 93 cases all 3 pathologists agreed on the same cell type, for 18 cases 2 out of 3 agreed, and for 3 cases there was no agreement. Across cell types with a minimum sample size of 10 cases, agreement between all three observers was {91.1%, 80.0%, 90.0%, 78.6%, 100.0%, 61.5%} for the high grade serous carcinoma, low grade serous carcinoma, endometrioid, mucinous, clear cell, and carcinosarcoma cell types respectively. These results indicate that unanimous agreement varied over a fairly wide range. However, additional research is needed to determine the importance of these differences in comparison studies. These results will be used to aid in the design and sizing of such a study comparing optical and digital pathology. In addition, the results will help in understanding the potential role computer-aided diagnosis has in helping to improve the agreement of pathologists for this task.

  10. Inter-annual and seasonal variations in transport to a measuring site in western Siberia, and their impact on the observed atmospheric CO2 mixing ratio

    International Nuclear Information System (INIS)

    Eneroth, Kristina

    2002-01-01

    Inter-annual and seasonal variations in atmospheric transport to a CO 2 measuring site in western Siberia were studied using three-dimensional trajectories. We identified large differences in transport between summer and winter, but also some differences between the years. Cluster analysis was applied to the trajectory data to determine to what degree different atmospheric flow patterns influence the variability of the atmospheric CO 2 mixing ratio. The observed CO 2 mixing ratio was also compared to observed CO 2 surface fluxes to study the impact of local sources and sinks. It was found that during July the correlation between atmospheric transport from distant source regions and CO 2 mixing ratios was poor. Furthermore the correlation was also weak between the CO 2 mixing ratio and the local eddy flux measurements. We conclude that the short-term variability in atmospheric CO 2 during summer probably is dominated by larger scale (tens up to one hundred kilometers) CO 2 surface fluxes and local meteorology. The weaker biogenic CO 2 fluxes during winter, resulted in CO 2 mixing ratios more clearly influenced by long-range transport Of CO 2 . However, the highest atmospheric CO 2 concentrations were not observed in connection with westerly winds representing transport of polluted air from Europe, but during periods with stagnant flow conditions. It was conjected that these high CO 2 mixing ratios were due to respired CO 2 trapped and accumulated in the lower parts of the planetary boundary layer. The mean duration for the identified flow patterns was in the order of two days, with a maximum duration of a week. This means that to have a chance to detect variations in CO 2 mixing ratio due to air mass changes the sampling frequency (e.g. flask samples and flight measurements) must be at least every other day. Our results show that the atmospheric transport varies with season, year and altitude. This, together with the heterogeneity of the source and sink regions are

  11. Assessing variability in chemical acute toxicity of unionid mussels: Influence of intra- and inter-laboratory testing, life stage, and species - SETAC Abstract

    Science.gov (United States)

    We developed a toxicity database for unionid mussels to examine the extent of intra- and inter-laboratory variability in acute toxicity tests with mussel larvae (glochidia) and juveniles; the extent of differential sensitivity of the two life stages; and the variation in sensitiv...

  12. Seasonal and annual variability of coastal sulphur plumes in the northern Benguela upwelling system.

    Science.gov (United States)

    Ohde, Thomas; Dadou, Isabelle

    2018-01-01

    We investigated the seasonal and annual variability of surface sulphur plumes in the northern Benguela upwelling system off Namibia because of their significant impacts on the marine ecosystem, fishing industry, aquaculture farming and tourism due to their toxic properties. We identified the sulphur plumes in ocean colour satellite data of the medium resolution imaging spectrometer (MERIS) for the 2002-2012 time period using the differences in the spectral properties of Namibian Benguela optical water types. The sulphur events have a strong seasonal cycle with pronounced main and off-seasons forced by local and remote-driven processes. The main peak season is in late austral summer and early austral autumn at the beginning of the annual upwelling cycle caused by increasing equatorwards alongshore winds. The sulphur plume activity is high between February and April during the seasonal oxygen minimum associated with the seasonal reduction of cross-shore ventilation of the bottom waters, the seasonal southernmost position of the Angola Benguela Frontal Zone, the seasonal maximum of water mass fractions of South Atlantic and Angola Gyre Central Waters as well as the seasonal arrival of the downwelling coastal trapped waves. The off-season is in austral spring and early austral summer during increased upwelling intensity and enhanced oxygen supply. The annual variability of sulphur events is characterized by very high activities in years 2004, 2005 and 2010 interrupted by periods of lower activity in years 2002 to 2003, 2006 to 2009 and 2011 to 2012. This result can be explained by the relative contributions or adding effects of local and remote-driven forces (from the equatorial area). The probability for the occurrence of sulphur plumes is enhanced in years with a lower annual mean of upwelling intensity, decreased oxygen supply associated with decreased lateral ventilation of bottom waters, more southern position of the Angola Benguela Frontal Zone, increased mass

  13. Seasonal and annual variability of coastal sulphur plumes in the northern Benguela upwelling system.

    Directory of Open Access Journals (Sweden)

    Thomas Ohde

    Full Text Available We investigated the seasonal and annual variability of surface sulphur plumes in the northern Benguela upwelling system off Namibia because of their significant impacts on the marine ecosystem, fishing industry, aquaculture farming and tourism due to their toxic properties. We identified the sulphur plumes in ocean colour satellite data of the medium resolution imaging spectrometer (MERIS for the 2002-2012 time period using the differences in the spectral properties of Namibian Benguela optical water types. The sulphur events have a strong seasonal cycle with pronounced main and off-seasons forced by local and remote-driven processes. The main peak season is in late austral summer and early austral autumn at the beginning of the annual upwelling cycle caused by increasing equatorwards alongshore winds. The sulphur plume activity is high between February and April during the seasonal oxygen minimum associated with the seasonal reduction of cross-shore ventilation of the bottom waters, the seasonal southernmost position of the Angola Benguela Frontal Zone, the seasonal maximum of water mass fractions of South Atlantic and Angola Gyre Central Waters as well as the seasonal arrival of the downwelling coastal trapped waves. The off-season is in austral spring and early austral summer during increased upwelling intensity and enhanced oxygen supply. The annual variability of sulphur events is characterized by very high activities in years 2004, 2005 and 2010 interrupted by periods of lower activity in years 2002 to 2003, 2006 to 2009 and 2011 to 2012. This result can be explained by the relative contributions or adding effects of local and remote-driven forces (from the equatorial area. The probability for the occurrence of sulphur plumes is enhanced in years with a lower annual mean of upwelling intensity, decreased oxygen supply associated with decreased lateral ventilation of bottom waters, more southern position of the Angola Benguela Frontal Zone

  14. The inter-annual variations and the long-term trends of monthly air temperatures in Iraq over the period 1941-2013

    Science.gov (United States)

    Muslih, Khamis Daham; Błażejczyk, Krzysztof

    2017-10-01

    Mean annual and monthly averages of mean (Tmean), maximum (Tmax) and minimum (Tmin) air temperature from seven stations in Iraq were analysed to detect the inter-annual variation, long-term temporal and spatial trends distribution over the period 1941-2013. Due to non-homogeneous problems, this period has been divided into two short separated periods (1941-1980 and 1995-2013), in order to compute temperature trends. In this context two statistical tests were used: linear regression and Mann-Kendall. The time series of mean annual temperature indicate the current warming period over Iraq identical with the global warming, which has started since the middle of seventh decade of the last century. The 2010 was the warmest year in all stations. Three distinct inter-annual temperature variation patterns were observed. These were probably the effects of micro-scale and meso-scale factors. The first one represents central and northern Iraq. The second represents the south of Iraq and Kirkuk station and the third one is a characteristic for eastern Iraq. Temperature trend analysis revealed that there are general upward trends with the strongest warming trends identified in the summer months which are around 89 % of the total significant monthly trends. Spatially, in both periods the southern region of Iraq is most affected by the warming trend in Tmean and Tmax. When considering Tmin, the southern and northern regions both are affected by warming with more pronounced trend intensity in the northern stations. No significant trend occurs Hai station in both periods and Baghdad has the still less trend value. In the first period the highest rise of Tmean and Tmax values are observed in July and June in Nasiriya station at 0.61 °C/decade and 0.63 °C/decade, respectively and in Mosul station for Tmin in August is 1.41 °C/decade. Moreover, in the period from 1995 to 2013, the highest warming trend of Tmean and Tmax were in Hai station for March at 1.48 °C/decade and at 1.85

  15. Seasonal and inter-annual dynamics of growth, non-structural carbohydrates and C stable isotopes in a Mediterranean beech forest.

    Science.gov (United States)

    Scartazza, Andrea; Moscatello, Stefano; Matteucci, Giorgio; Battistelli, Alberto; Brugnoli, Enrico

    2013-07-01

    Seasonal and inter-annual dynamics of growth, non-structural carbohydrates (NSC) and carbon isotope composition (δ(13)C) of NSC were studied in a beech forest of Central Italy over a 2-year period characterized by different environmental conditions. The net C assimilated by forest trees was mainly used to sustain growth early in the season and to accumulate storage carbohydrates in trunk and root wood in the later part of the season, before leaf shedding. Growth and NSC concentration dynamics were only slightly affected by the reduced soil water content (SWC) during the drier year. Conversely, the carbon isotope analysis on NSC revealed seasonal and inter-annual variations of photosynthetic and post-carboxylation fractionation processes, with a significant increase in δ(13)C of wood and leaf soluble sugars in the drier summer year than in the wetter one. The highly significant correlation between δ(13)C of leaf soluble sugars and SWC suggests a decrease of the canopy C isotope discrimination and, hence, an increased water-use efficiency with decreasing soil water availability. This may be a relevant trait for maintaining an acceptable plant water status and a relatively high C sink capacity during dry seasonal periods. Our results suggest a short- to medium-term homeostatic response of the Collelongo beech stand to variations in water availability and solar radiation, indicating that this Mediterranean forest was able to adjust carbon-water balance in order to prevent C depletion and to sustain plant growth and reserve accumulation during relatively dry seasons.

  16. Inter-annual variation in the response of leaf-out onset to soil moisture increase in a teak plantation in northern Thailand.

    Science.gov (United States)

    Yoshifuji, Natsuko; Igarashi, Yasunori; Tanaka, Nobuaki; Tanaka, Katsunori; Sato, Takanori; Tantasirin, Chatchai; Suzuki, Masakazu

    2014-11-01

    To understand the impact of inter-annual climate change on vegetation-atmosphere mass and energy exchanges, it has become necessary to explore changes in leaf-out onset in response to climatic fluctuations. We examined the response of leaf-out and transpiration onset dates to soil moisture in a teak plantation in northern Thailand based on a 12-year leaf area index and sap flow measurements. The date of leaf-out and transpiration onset varied between years by up to 40 days, and depended on the initial date when the relative extractable water in a soil layer of 0-0.6 m (Θ) was greater than 0.2 being consistent with our previous results. Our new finding is that the delay in leaf-out and transpiration onset relative to the initial date when Θ > 0.2 increases linearly as the initial date on which Θ > 0.2 becomes earlier. The delay spans about 20 days in years when Θ > 0.2 occurs in March (the late dry season)-much earlier than usual because of heavy pre-monsoon rainfalls-while there is little delay in years when Θ > 0.2 occurs in May. This delay indicates the influence of additional factors on leaf-out onset, which controls the delay in the response of leaf-out to soil moisture increase. The results increased our knowledge about the pattern and extent of the changes in leaf phenology that occur in response to the inter-annual climate variation in tropical regions, where, in particular, such research is needed.

  17. Degree-day accumulation influences annual variability in growth of age-0 walleye

    Science.gov (United States)

    Uphoff, Christopher S.; Schoenebeck, Casey W.; Hoback, W. Wyatt; Koupal, Keith D.; Pope, Kevin L.

    2013-01-01

    The growth of age-0 fishes influences survival, especially in temperate regions where size-dependent over-winter mortality can be substantial. Additional benefits of earlier maturation and greater fecundity may exist for faster growing individuals. This study correlated prey densities, growing-degree days, water-surface elevation, turbidity, and chlorophyll a with age-0 walleye Sander vitreus growth in a south-central Nebraska irrigation reservoir. Growth of age-0 walleye was variable between 2003 and 2011, with mean lengths ranging from 128 to 231 mm by fall (September 30th–October 15th). A set of a priori candidate models were used to assess the relative support of explanatory variables using Akaike's information criterion (AIC). A temperature model using the growing degree-days metric was the best supported model, describing 65% of the variability in annual mean lengths of age-0 walleye. The second and third best supported models included the variables chlorophyll a (r2 = 0.49) and larval freshwater drum density (r2 = 0.45), respectively. There have been mixed results concerning the importance of temperature effects on growth of age-0 walleye. This study supports the hypothesis that temperature is the most important predictor of age-0 walleye growth near the southwestern limits of its natural range.

  18. The use of GIS in determining the impacts of climate variability on ...

    African Journals Online (AJOL)

    This study developed a Geographical Information Systems (GIS) database and mapped inter-annual changes in tuber crop yield, as a response to inter-annual rainfall variability in the Guinea Savanna ecological zone of Nigeria. It also related the spatiotemporal variability in rainfall with tuber yields. Two major tuber crops, ...

  19. Inter-annual precipitation variabiity inferred from late Holocene speleothem records from Fiji: implications for SPCZ localisation and ENSO behaviour

    Science.gov (United States)

    Mattey, D.; Stephens, M.; Hoffmann, D.; Brett, M.

    2015-12-01

    The modern tropical Fiji climate is characterised by seasonal rainfall controlled by the position of the South Pacific Convergence Zone (SPCZ). Interannual rainfall is strongly modulated on decadal timescales by ENSO with higher rainfall associated with La Nina events. Voli Voli cave near Sigatoga (Viti Levu) is a stream passage that has been monitored since 2009. A U-Th dated laminated speleothem spans a 1500 year interval across the transition from the Medieval Warm Period into the Little Ice Age marked by a fabric change from finely laminated calcite with thin clay layers, to white well-laminated calcite. The older record is characterised by rising δ13C values followed by a rapid decrease in δ13C around 1200 AD. Evidence from cave monitoring shows that cave air CO2 levels are strongly seasonal as a result of greater ventilation by winter trade winds and high resolution δ13C record shows regularly spaced peaks correlated with paired laminae and cycles in P and S which provide annual markers driven by rainfall and seasonal ventilation. δ18O values remain relatively unchanged throughout the record but micromilling at sub-annual resolution reveals systematic cycles in δ18O that span groups of paired laminae with an inferred periodicity of 3-7 years i.e. a similar frequency to modern ENSO. The presence of these sub-decadal cycles in δ18O may be a result of a combination of factors. The amplitude of 2-3‰ would be equivalent to an amount-effect related change in annual precipitation of around 50% but an additional smoothing process, perhaps a result of aquifer storage, is required to attenuate interannual variance in precipitation. The Voli Voli record provides evidence of an underlying climatic change to more frequent La Niña conditions from 1200 AD and may be associated with increased conflict, shifts in settlements and changes in subsistence strategies on the island. Coeval speleothem isotope records from tropical Pacific Islands provide a provide a

  20. In situ study of the impact of inter- and intra-reader variability on region of interest (ROI) analysis in preclinical molecular imaging.

    Science.gov (United States)

    Habte, Frezghi; Budhiraja, Shradha; Keren, Shay; Doyle, Timothy C; Levin, Craig S; Paik, David S

    2013-01-01

    We estimated reader-dependent variability of region of interest (ROI) analysis and evaluated its impact on preclinical quantitative molecular imaging. To estimate reader variability, we used five independent image datasets acquired each using microPET and multispectral fluorescence imaging (MSFI). We also selected ten experienced researchers who utilize molecular imaging in the same environment that they typically perform their own studies. Nine investigators blinded to the data type completed the ROI analysis by drawing ROIs manually that delineate the tumor regions to the best of their knowledge and repeated the measurements three times, non-consecutively. Extracted mean intensities of voxels within each ROI are used to compute the coefficient of variation (CV) and characterize the inter- and intra-reader variability. The impact of variability was assessed through random samples iterated from normal distributions for control and experimental groups on hypothesis testing and computing statistical power by varying subject size, measured difference between groups and CV. The results indicate that inter-reader variability was 22.5% for microPET and 72.2% for MSFI. Additionally, mean intra-reader variability was 10.1% for microPET and 26.4% for MSFI. Repeated statistical testing showed that a total variability of CV variability has been observed mainly due to differences in the ROI placement and geometry drawn between readers, which may adversely affect statistical power and erroneously lead to negative study outcomes.

  1. The Influences of Drought and Land-Cover Conversion on Inter-Annual Variation of NPP in the Three-North Shelterbelt Program Zone of China Based on MODIS Data.

    Directory of Open Access Journals (Sweden)

    Dailiang Peng

    Full Text Available Terrestrial ecosystems greatly contribute to carbon (C emission reduction targets through photosynthetic C uptake.Net primary production (NPP represents the amount of atmospheric C fixed by plants and accumulated as biomass. The Three-North Shelterbelt Program (TNSP zone accounts for more than 40% of China's landmass. This zone has been the scene of several large-scale ecological restoration efforts since the late 1990s, and has witnessed significant changes in climate and human activities.Assessing the relative roles of different causal factors on NPP variability in TNSP zone is very important for establishing reasonable local policies to realize the emission reduction targets for central government. In this study, we examined the relative roles of drought and land cover conversion(LCC on inter-annual changes of TNSP zone for 2001-2010. We applied integrated correlation and decomposition analyses to a Standardized Evapotranspiration Index (SPEI and MODIS land cover dataset. Our results show that the 10-year average NPP within this region was about 420 Tg C. We found that about 60% of total annual NPP over the study area was significantly correlated with SPEI (p<0.05. The LCC-NPP relationship, which is especially evident for forests in the south-central area, indicates that ecological programs have a positive impact on C sequestration in the TNSP zone. Decomposition analysis generally indicated that the contributions of LCC, drought, and other Natural or Anthropogenic activities (ONA to changes in NPP generally had a consistent distribution pattern for consecutive years. Drought and ONA contributed about 74% and 23% to the total changes in NPP, respectively, and the remaining 3% was attributed to LCC. Our results highlight the importance of rainfall supply on NPP variability in the TNSP zone.

  2. Intra- and inter-annual trends in phosphorus loads and comparison with nitrogen loads to Rehoboth Bay, Delaware (USA)

    Science.gov (United States)

    Volk, J.A.; Scudlark, J.R.; Savidge, K.B.; Andres, A.S.; Stenger, R.J.; Ullman, W.J.

    2012-01-01

    Monthly phosphorus loads from uplands, atmospheric deposition, and wastewater to Rehoboth Bay (Delaware) were determined from October 1998 to April 2002 to evaluate the relative importance of these three sources of P to the Bay. Loads from a representative subwatershed were determined and used in an areal extrapolation to estimate the upland load from the entire watershed. Soluble reactive phosphorus (SRP) and dissolved organic P (DOP) are the predominant forms of P in baseflow and P loads from the watershed are highest during the summer months. Particulate phosphorus (PP) becomes more significant in stormflow and during periods with more frequent or larger storms. Atmospheric deposition of P is only a minor source of P to Rehoboth Bay. During the period of 1998-2002, wastewater was the dominant external source of P to Rehoboth Bay, often exceeding all other P sources combined. Since 2002, however, due to technical improvements to the sole wastewater plant discharging directly to the Bay, the wastewater contribution of P has been significantly reduced and upland waters are now the principal source of P on an annualized basis. Based on comparison of N and P loads, primary productivity and biomass carrying capacity in Rehoboth Bay should be limited by P availability. However, due to the contrasting spatial and temporal patterns of N and P loading and perhaps internal cycling within the ecosystem, spatial and temporal variations in N and P-limitation within Rehoboth Bay are likely. ?? 2011 Elsevier Ltd.

  3. [Inter-observer variability of decision concerning the route of delivery in case of one previous cesarean section and abnormal pelvic measures].

    Science.gov (United States)

    Bourdon, M; Ceccaldi, P F; Girard, G; Koskas, M; Goffinet, F; Le Ray, C

    2016-11-01

    To study inter-observer variability of decision concerning the route of delivery using pelvimetry in case of one previous cesarean section and abnormal pelvic measures. Observational study conducted in 2014 in 4 university maternity units among 36 obstetricians. Two groups of obstetricians - as they practiced in a center where pelvimetry was routinely performed (n=12) or not (n=24) - had to choose a route of delivery for 10 clinical cases of women with a single uterine scar and a tight pelvis. The "routine pelvimetry" group had pelvimetry results. The group "no pelvimetry" became aware of pelvimetry results as a second step and had to indicate whether this information changed or not their management. The measurement of the inter-observer variability was estimated by estimating the proportion of agreement according to Grant method. The proportion of agreements of an attempted vaginal delivery between obstetricians in the group "routine pelvimetry" was 64.7% (95% CI [61-68.5]) and 97.3% (95% CI [96.4 to 98.3]) in the group "no pelvimetry", prior knowledge of pelvimetry results. An attempted vaginal delivery was decided in 77.5% versus 98.7% (Pcesarean section, in case of tight pelvis discovered after pelvimetry, inter-observer variability of decision concerning the route of delivery is increased. Centers that choose to continue using the routine pelvimetry should develop procedures to limit this variability. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. Effects of climate variables on intra-annual stem radial increment in Pinus cembra (L.) along the alpine treeline ecotone

    OpenAIRE

    GRUBER, Andreas; ZIMMERMANN, Jolanda; WIESER, Gerhard; OBERHUBER, Walter

    2009-01-01

    Within the alpine treeline ecotone tree growth is increasingly restricted by extreme climate conditions. Although intra-annual stem growth recorded by dendrometers can be linked to climate, stem diameter increments in slow-growing subalpine trees are masked by changes in tree water status.We tested the hypothesis that intra-annual radial stem growth in Pinus cembra is influenced by different climate variables along the treeline ecotone in the Austrian Alps. Dendrometer traces were compared wi...

  5. Exploring intra- and inter-reader variability in uni-dimensional, bi-dimensional, and volumetric measurements of solid tumors on CT scans reconstructed at different slice intervals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Binsheng, E-mail: bz2166@columbia.edu [Department of Radiology, Columbia University Medical Center, New York, NY (United States); Tan, Yongqiang, E-mail: yt2314@columbia.edu [Department of Radiology, Columbia University Medical Center, New York, NY (United States); Bell, Daniel J., E-mail: doctordj@gmail.com [North Middlesex University Hospital, London (United Kingdom); Marley, Sarah E., E-mail: sarahthepurplelady@hotmail.com [AstraZeneca, Alderley Park, Macclesfield, Cheshire (United Kingdom); Guo, Pingzhen, E-mail: gpz_jn@sina.com [Department of Radiology, Columbia University Medical Center, New York, NY (United States); Mann, Helen, E-mail: helen.mann@astrazaneca.com [AstraZeneca, Alderley Park, Macclesfield, Cheshire (United Kingdom); Scott, Marietta L.J., E-mail: marietta.scott@astrazeneca.com [AstraZeneca, Alderley Park, Macclesfield, Cheshire (United Kingdom); Schwartz, Lawrence H., E-mail: lhs2120@columbia.edu [Department of Radiology, Columbia University Medical Center, New York, NY (United States); Ghiorghiu, Dana C., E-mail: dana.ghiorghiu@astrazeneca.com [AstraZeneca, Alderley Park, Macclesfield, Cheshire (United Kingdom)

    2013-06-15

    Objective: Understanding magnitudes of variability when measuring tumor size may be valuable in improving detection of tumor change and thus evaluating tumor response to therapy in clinical trials and care. Our study explored intra- and inter-reader variability of tumor uni-dimensional (1D), bi-dimensional (2D), and volumetric (VOL) measurements using manual and computer-aided methods (CAM) on CT scans reconstructed at different slice intervals. Materials and methods: Raw CT data from 30 patients enrolled in oncology clinical trials was reconstructed at 5, 2.5, and 1.25 mm slice intervals. 118 lesions in the lungs, liver, and lymph nodes were analyzed. For each lesion, two independent radiologists manually and, separately, using computer software, measured the maximum diameter (1D), maximum perpendicular diameter, and volume (CAM only). One of them blindly repeated the measurements. Intra- and inter-reader variability for the manual method and CAM were analyzed using linear mixed-effects models and Bland–Altman method. Results: For the three slice intervals, the maximum coefficients of variation for manual intra-/inter-reader variability were 6.9%/9.0% (1D) and 12.3%/18.0% (2D), and for CAM were 5.4%/9.3% (1D), 11.3%/18.8% (2D) and 9.3%/18.0% (VOL). Maximal 95% reference ranges for the percentage difference in intra-reader measurements for manual 1D and 2D, and CAM VOL were (−15.5%, 25.8%), (−27.1%, 51.6%), and (−22.3%, 33.6%), respectively. Conclusions: Variability in measuring the diameter and volume of solid tumors, manually and by CAM, is affected by CT slice interval. The 2.5 mm slice interval provides the least measurement variability. Among the three techniques, 2D has the greatest measurement variability compared to 1D and 3D.

  6. Exploring intra- and inter-reader variability in uni-dimensional, bi-dimensional, and volumetric measurements of solid tumors on CT scans reconstructed at different slice intervals

    International Nuclear Information System (INIS)

    Zhao, Binsheng; Tan, Yongqiang; Bell, Daniel J.; Marley, Sarah E.; Guo, Pingzhen; Mann, Helen; Scott, Marietta L.J.; Schwartz, Lawrence H.; Ghiorghiu, Dana C.

    2013-01-01

    Objective: Understanding magnitudes of variability when measuring tumor size may be valuable in improving detection of tumor change and thus evaluating tumor response to therapy in clinical trials and care. Our study explored intra- and inter-reader variability of tumor uni-dimensional (1D), bi-dimensional (2D), and volumetric (VOL) measurements using manual and computer-aided methods (CAM) on CT scans reconstructed at different slice intervals. Materials and methods: Raw CT data from 30 patients enrolled in oncology clinical trials was reconstructed at 5, 2.5, and 1.25 mm slice intervals. 118 lesions in the lungs, liver, and lymph nodes were analyzed. For each lesion, two independent radiologists manually and, separately, using computer software, measured the maximum diameter (1D), maximum perpendicular diameter, and volume (CAM only). One of them blindly repeated the measurements. Intra- and inter-reader variability for the manual method and CAM were analyzed using linear mixed-effects models and Bland–Altman method. Results: For the three slice intervals, the maximum coefficients of variation for manual intra-/inter-reader variability were 6.9%/9.0% (1D) and 12.3%/18.0% (2D), and for CAM were 5.4%/9.3% (1D), 11.3%/18.8% (2D) and 9.3%/18.0% (VOL). Maximal 95% reference ranges for the percentage difference in intra-reader measurements for manual 1D and 2D, and CAM VOL were (−15.5%, 25.8%), (−27.1%, 51.6%), and (−22.3%, 33.6%), respectively. Conclusions: Variability in measuring the diameter and volume of solid tumors, manually and by CAM, is affected by CT slice interval. The 2.5 mm slice interval provides the least measurement variability. Among the three techniques, 2D has the greatest measurement variability compared to 1D and 3D

  7. Variable Reporting by Authors Presenting Arthroplasty Research at Multiple Annual Conferences.

    Science.gov (United States)

    Choo, Kevin J; Yi, Paul H; Burns, Robert; Mohan, Rohith; Wong, Kevin

    2017-01-01

    Prior studies have demonstrated discrepancies in financial conflict of interest (COI) disclosure among authors presenting research at multiple spine and sports medicine conferences. The purpose of this study was to quantify the variability of self-reported financial disclosures of individual authors presenting at multiple arthroplasty conferences during the same year. The author disclosure information published for the 2012 annual meetings of the American Academy of Orthopaedic Surgeons (AAOS), American Association of Hip and Knee Surgeons, the Hip Society, and the Knee Society were compiled. We tabulated the author disclosures, the number of companies/entities represented, and the types of disclosures reported. The disclosures made by authors presenting at more than one meeting were then compared for discrepancies. Of the 209 authors who presented at both the AAOS and American Association of Hip and Knee Surgeons meetings, 79 (37.79%) demonstrated discrepancies in their disclosures with 7 (8.8%) reporting no disclosures to the AAOS. Of the 84 authors who presented at both the AAOS and Hip Society meetings, 1 (1.19%) had discrepancies in their disclosures. Of the 52 authors who presented at both the AAOS and Knee Society meetings, 2 (3.84%) had discrepancies in their disclosures. There is variability in reported financial COIs by authors presenting at multiple arthroplasty conferences within the same year. Further work is warranted to improve transparency of COI disclosures among arthroplasty surgeons presenting research at national meetings. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Hydrology of the North Klondike River: carbon export, water balance and inter-annual climate influences within a sub-alpine permafrost catchment.

    Science.gov (United States)

    Lapp, Anthony; Clark, Ian; Macumber, Andrew; Patterson, Tim

    2017-10-01

    Arctic and sub-arctic watersheds are undergoing significant changes due to recent climate warming and degrading permafrost, engendering enhanced monitoring of arctic rivers. Smaller catchments provide understanding of discharge, solute flux and groundwater recharge at the process level that contributes to an understanding of how larger arctic watersheds are responding to climate change. The North Klondike River, located in west central Yukon, is a sub-alpine permafrost catchment, which maintains an active hydrological monitoring station with a record of >40 years. In addition to being able to monitor intra-annual variability, this data set allows for more complex analysis of streamflow records. Streamflow data, geochemistry and stable isotope data for 2014 show a groundwater-dominated system, predominantly recharged during periods of snowmelt. Radiocarbon is shown to be a valuable tracer of soil zone recharge processes and carbon sources. Winter groundwater baseflow contributes 20 % of total annual discharge, and accounts for up to 50 % of total river discharge during the spring and summer months. Although total stream discharge remains unchanged, mean annual groundwater baseflow has increased over the 40-year monitoring period. Wavelet analysis reveals a catchment that responds to El Niño and longer solar cycles, as well as climatic shifts such as the Pacific Decadal Oscillation. Dedicated to Professor Peter Fritz on the occasion of his 80th birthday.

  9. Variability in the Inter-Group Attitudes of White Children: What We Can Learn from Their Ethnic Identity Labels

    Science.gov (United States)

    Brown, Christia Spears; Spatzier, Agnieszka; Tobin, Mollie

    2010-01-01

    The current study examined the ethnic identity of White (N = 120), Latino (N = 87), and African-American (N = 65) children and early adolescents (aged = 9-14 years), with an emphasis on whether the specific ethnic label White children used to describe themselves might reflect differences in their inter-group attitudes and whether those differences…

  10. Leishmaniasis Direct Agglutination Test: Using Pictorials as Training Materials to Reduce Inter-Reader Variability and Improve Accuracy

    NARCIS (Netherlands)

    Adams, Emily R.; Jacquet, Diane; Schoone, Gerard; Gidwani, Kamlesh; Boelaert, Marleen; Cunningham, Jane

    2012-01-01

    Background: The Direct Agglutination Test (DAT) has a high diagnostic accuracy and remains, in some geographical areas, part of the diagnostic algorithm for Visceral Leishmaniasis (VL). However, subjective interpretation of results introduces potential for inter-reader variation. We report an

  11. Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA.

    Science.gov (United States)

    Navrátil, Tomas; Norton, Stephen A; Fernandez, Ivan J; Nelson, Sarah J

    2010-12-01

    Mean annual concentration of SO4(-2) in wet-only deposition has decreased between 1988 and 2006 at the paired watershed study at Bear Brook Watershed in Maine, USA (BBWM) due to substantially decreased emissions of SO(2). Emissions of NO(x) have not changed substantially, but deposition has declined slightly at BBWM. Base cations, NH4+, and Cl(-) concentrations were largely unchanged, with small irregular changes of Bear Brook (EB), the reference stream, has been slowly responding to reduced but still elevated acid deposition. Calcium and Mg have declined fairly steadily and faster than SO4(-2), with consequent acidification (lower pH and higher inorganic Al). Eighteen years of experimental treatment with (NH(4))(2)SO(4) enhanced acidification of West Bear Brook's (WB) watershed. Despite the manipulation, NH4+ concentration remained below detection limits at WB, while leaching of NO3- increased. The seasonal pattern for NO3- concentrations in WB, however, remained similar to EB. Mean monthly concentrations of SO4(-2) have increased in WB since 1989, initially only during periods of high flow, but gradually also during base flow. Increases in mean monthly concentrations of Ca(2+), Mg(2+), and K(+) due to the manipulation occurred from 1989 until about 1995, during the depletion of base cations in shallow flow paths in WB. Progressive depletion of Ca and Mg at greater soil depth occurred, causing stream concentrations to decline to pre-manipulation values. Mean monthly Si concentrations did not change in EB or WB, suggesting that the manipulation had no effect on mineral weathering rates. DOC concentrations in both streams did not exhibit inter- or intra-annual trends.

  12. Measuring and modeling carbon stock change estimates for US forests and uncertainties from apparent inter-annual variability

    Science.gov (United States)

    James E. Smith; Linda S. Heath

    2015-01-01

    Our approach is based on a collection of models that convert or augment the USDA Forest Inventory and Analysis program survey data to estimate all forest carbon component stocks, including live and standing dead tree aboveground and belowground biomass, forest floor (litter), down deadwood, and soil organic carbon, for each inventory plot. The data, which include...

  13. Intra-seasonal oscillations associated with Indian Ocean warm pool and summer monsoon rainfall and their inter-annual variability

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Nisha, P.G.; Sathe, P.V.; Sivakumar, K.U.

    and SST at the East Coast by 20 to 30 days, the coefficient of correlation 8 did not support a strong relationship. The OLR, again failed to support the 20 to 30 days lead showed by SST and WS. Strong and significant relationships between rainfall... supports high OLR with the same phase lag. Therefore the difference in phase lag between OLR and rainfall is anticipated and is in line with the argument that a reversal of relationship is expected with the same 20 to 30 days phase lag to support...

  14. Drivers of inter-annual variability in Net Ecosystem Exchange in a semi-arid savanna ecosystem, South Africa

    CSIR Research Space (South Africa)

    Archibald, SA

    2009-01-01

    Full Text Available and filling gaps in eddy-covariance data in semi-arid systems were developed. Net ecosystem exchange (NEE) in these systems occurs as pulses associated with rainfall events, a pattern not well-represented in current standard gap-filling procedures developed...

  15. Seasonal and inter-annual variability of surface circulation in the Bay of Bengal from TOPEX/Poseidon altimetry

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, Y.K.; Murty, V.S.N.; Sarma, Y.V.B.

    were negatively correlated to the SSTA in the Western Equatorial Pacific both during El Nino and La Ninio. The coastal trapped Kelvin waves and radiated Rossby waves provide the oceanic link between the equatorial region and the bay for the observed...

  16. Inter-annual variability of sea surface temperature, wind speed and sea surface height anomaly over the tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Pankajakshan, T.; Sathe, P.V.

    the fields during 1994 and 1997 coinciding with the El Nino events. The reversal of westerlies at the equator appeared to be responsible for the formation of anomalous cooling and warming near Sumatra and Somali, respectively. The oscillation of westerlies...

  17. Detecting inter-annual variability in the phenological characteristics of southern Africa’s vegetation using satellite imagery

    CSIR Research Space (South Africa)

    Wessels, Konrad J

    2011-01-01

    Full Text Available Vegetation phenology refers to the timing of seasonal biological events (for example, bud burst, leaf unfolding, vegetation growth and leaf senescence) and biotic and abiotic forces that control these. Daily, coarse-resolution satellite imagery...

  18. Inter-annual variation in prevalence and intensity of mite parasitism relates to appearance and expression of damselfly resistance.

    Science.gov (United States)

    Nagel, Laura; Robb, Tonia; Forbes, Mark R

    2010-02-14

    Insects can resist parasites using the costly process of melanotic encapsulation. This form of physiological resistance has been studied under laboratory conditions, but the abiotic and biotic factors affecting resistance in natural insect populations are not well understood. Mite parasitism of damselflies was studied in a temperate damselfly population over seven seasons to determine if melanotic encapsulation of mite feeding tubes was related to degree of parasitism, host sex, host size, emergence timing, duration of the emergence period, and average daily air temperature. Although parasite prevalence in newly emerged damselflies was > 77% each year, hosts did not resist mites in the early years of study. Resistance began the year that there was a dramatic increase in the number of mites on newly emerged damselflies. Resistance continued to be correlated with mite prevalence and intensity throughout the seven-year study. However, the percentage of hosts resisting only ranged from 0-13% among years and resistance was not sex-biased and was not correlated with host size. Resistance also was not correlated with air temperature or with timing or duration of damselfly emergence. Resistance in host damselflies was weakly and variably expressed over the study period. Factors such as temperature, which have been identified in laboratory studies as contributing to resistance by similar hosts, can be irrelevant in natural populations. This lack of temperature effect may be due to the narrow range in temperatures observed at host emergence among years. Degree of mite parasitism predicted both the appearance and continued expression of resistance among parasitized damselflies.

  19. 'Your comments are meaner than your score': score calibration talk influences intra- and inter-panel variability during scientific grant peer review.

    Science.gov (United States)

    Pier, Elizabeth L; Raclaw, Joshua; Kaatz, Anna; Brauer, Markus; Carnes, Molly; Nathan, Mitchell J; Ford, Cecilia E

    2017-01-01

    In scientific grant peer review, groups of expert scientists meet to engage in the collaborative decision-making task of evaluating and scoring grant applications. Prior research on grant peer review has established that inter-reviewer reliability is typically poor. In the current study, experienced reviewers for the National Institutes of Health (NIH) were recruited to participate in one of four constructed peer review panel meetings. Each panel discussed and scored the same pool of recently reviewed NIH grant applications. We examined the degree of intra-panel variability in panels' scores of the applications before versus after collaborative discussion, and the degree of inter-panel variability. We also analyzed videotapes of reviewers' interactions for instances of one particular form of discourse- Score Calibration Talk -as one factor influencing the variability we observe. Results suggest that although reviewers within a single panel agree more following collaborative discussion, different panels agree less after discussion, and Score Calibration Talk plays a pivotal role in scoring variability during peer review. We discuss implications of this variability for the scientific peer review process.

  20. Growing Region Segmentation Software (GRES) for quantitative magnetic resonance imaging of multiple sclerosis: intra- and inter-observer agreement variability: a comparison with manual contouring method

    International Nuclear Information System (INIS)

    Parodi, Roberto C.; Sardanelli, Francesco; Renzetti, Paolo; Rosso, Elisabetta; Losacco, Caterina; Ferrari, Alessandra; Levrero, Fabrizio; Pilot, Alberto; Inglese, Matilde; Mancardi, Giovanni L.

    2002-01-01

    Lesion area measurement in multiple sclerosis (MS) is one of the key points in evaluating the natural history and in monitoring the efficacy of treatments. This study was performed to check the intra- and inter-observer agreement variability of a locally developed Growing Region Segmentation Software (GRES), comparing them to those obtained using manual contouring (MC). From routine 1.5-T MRI study of clinically definite multiple sclerosis patients, 36 lesions seen on proton-density-weighted images (PDWI) and 36 enhancing lesion on Gd-DTPA-BMA-enhanced T1-weighted images (Gd-T1WI) were randomly chosen and were evaluated by three observers. The mean range of lesion size was 9.9-536.0 mm 2 on PDWI and 3.6-57.2 mm 2 on Gd-T1WI. The median intra- and inter-observer agreement were, respectively, 97.1 and 90.0% using GRES on PDWI, 81.0 and 70.0% using MC on PDWI, 88.8 and 80.0% using GRES on Gd-T1WI, and 85.8 and 70.0% using MC on Gd-T1WI. The intra- and inter-observer agreements were significantly greater for GRES compared with MC (P<0.0001 and P=0.0023, respectively) for PDWI, while no difference was found between GRES an MC for Gd-T1WI. The intra-observer variability for GRES was significantly lower on both PDWI (P=0.0001) and Gd-T1WI (P=0.0067), whereas for MC the same result was found only for PDWI (P=0.0147). These data indicate that GRES reduces both the intra- and the inter-observer variability in assessing the area of MS lesions on PDWI and may prove useful in multicentre studies. (orig.)

  1. Inter-annual differences of ichthyofauna structure of the Guadiana estuary and adjacent coastal area (SE Portugal/SW Spain): Before and after Alqueva dam construction

    Science.gov (United States)

    Chícharo, M. Alexandra; Chícharo, Luis; Morais, Pedro

    2006-10-01

    The objective of this study was to evaluate how inter-annual changes in the volume of freshwater input and water parameters (salinity, temperature, major dissolved nutrients, seston and chlorophyll a) affect fish assemblages in the Guadiana estuary (South Portugal). During the sampling period (two distinct hydrological years), 56 fish species were identified. Anchovies ( Engraulis encrasicolus) and barbells ( Barbus species) dominated the abundances in the high inflow year (2001), but Pomatoschistus species were the most important taxa in the low inflow year (2002). Barbells and Portuguese toadfish ( Halobatrachus didactylus) dominated the biomass in both years under different inflow conditions, but a reduction in barbells' biomass occurred during the low inflow year. Multivariate analysis indicated a persistent spatial structuring of the estuarine community for both years and in different seasonal periods. Changes in salinity and seston, which were mainly due to changes in freshwater input, had an important influence on the structure of the fish assemblages. In 2002, the increased salinity in the upper estuary allowed colonization by marine species of an area that usually contains freshwater, decreasing even more the habitat for indigenous freshwater species in the downstream area of the Guadiana River. There was also a decrease in the abundances of planktivorous and omnivorous fishes and an increase in carnivorous fishes during the low inflow year. As fishes in these systems are important regulators of processes in the trophic web, changes in the dominant feeding groups can have consequences on water quality, particularly in relation to the occurrence of plankton blooms.

  2. Assessment of a new seasonal to inter-annual operational Great Lakes water supply, water levels, and connecting channel flow forecasting system

    Science.gov (United States)

    Gronewold, A.; Fry, L. M.; Hunter, T.; Pei, L.; Smith, J.; Lucier, H.; Mueller, R.

    2017-12-01

    The U.S. Army Corps of Engineers (USACE) has recently operationalized a suite of ensemble forecasts of Net Basin Supply (NBS), water levels, and connecting channel flows that was developed through a collaboration among USACE, NOAA's Great Lakes Environmental Research Laboratory, Ontario Power Generation (OPG), New York Power Authority (NYPA), and the Niagara River Control Center (NRCC). These forecasts are meant to provide reliable projections of potential extremes in daily discharge in the Niagara and St. Lawrence Rivers over a long time horizon (5 years). The suite of forecasts includes eight configurations that vary by (a) NBS model configuration, (b) meteorological forcings, and (c) incorporation of seasonal climate projections through the use of weighting. Forecasts are updated on a weekly basis, and represent the first operational forecasts of Great Lakes water levels and flows that span daily to inter-annual horizons and employ realistic regulation logic and lake-to-lake routing. We will present results from a hindcast assessment conducted during the transition from research to operation, as well as early indications of success rates determined through operational verification of forecasts. Assessment will include an exploration of the relative skill of various forecast configurations at different time horizons and the potential for application to hydropower decision making and Great Lakes water management.

  3. Suitability of quality control materials for prostate-specific antigen (PSA) measurement: inter-method variability of common tumor marker control materials.

    Science.gov (United States)

    Vucetic, Zivjena; Dnistrian, Ann; Nilsson, Olle; Lilja, Hans G; Plebani, Mario

    2013-04-01

    Quality control materials with minimal inter-assay differences and clinically relevant proportions of different molecular forms of the analyte are needed to optimize intra- and inter-laboratory accuracy and precision. We assessed if clinically relevant total prostate-specific antigen (tPSA) levels were present in seven commercially available Multi Constituent Tumor Marker Controls (MC-TMC). Further, we determined the concentration of free PSA (fPSA) and calculated the percentage of free PSA (%fPSA) in all materials. Finally, we determined variability of TMC materials across several commonly used PSA platforms. All MC-TMC materials contained at least one concentration of tPSA in normal and pathologic range. Control materials varied in the amount of fPSA and %fPSA, with most controls consisting of fPSA only and only one MC-TMC containing medically relevant levels of around 35% fPSA. Only a minority of MC-TMC materials showed minimal variability across four PSA methods while the majority of PSA controls showed wide inter-method differences. Use of many commercially available controls for PSA could lead to biased PSA measurements because they contain medically irrelevant proportions of fPSA and show significant variation among different PSA assay platforms.

  4. Predicting the distribution of a threatened albatross: The importance of competition, fisheries and annual variability

    Science.gov (United States)

    Catry, P.; Lemos, R. T.; Brickle, P.; Phillips, R. A.; Matias, R.; Granadeiro, J. P.

    2013-03-01

    The ability to predict the distribution of threatened marine predators is essential to inform spatially explicit seascape management. We tracked 99 individual black-browed albatrosses Thalassarche melanophris from two Falkland Islands’ colonies in 2 years. We modeled the observed distribution of foraging activity taking environmental variables, fisheries activity (derived from vessel monitoring system data), accessibility to feeding grounds and intra-specific competition into account. The resulting models had sufficient generality to make reasonable predictions for different years and colonies, which allows temporal and spatial variation to be incorporated into the decision making process by managers for regions and seasons where available information is incomplete. We also illustrated that long-ranging birds from colonies separated by as little as 75 km can show important spatial segregation at sea, invalidating direct or uncorrected extrapolation from one colony to neighboring ones. Fisheries had limited influence on albatross distribution, despite the well known scavenging behavior of these birds. The models developed here have potentially wide application to the identification of sensitive geographical areas where special management practices (such as fisheries closures) could be implemented, and would predict how these areas are likely to move with annual and seasonal changes in environmental conditions.

  5. Annual dynamics of North Sea bacterioplankton: seasonal variability superimposes short-term variation.

    Science.gov (United States)

    Lucas, Judith; Wichels, Antje; Teeling, Hanno; Chafee, Meghan; Scharfe, Mirco; Gerdts, Gunnar

    2015-09-01

    The dynamics of coastal marine microbial communities are driven by seasonally changing abiotic and biotic factors as well as by rapidly occurring short-term changes such as river fresh water influxes or phytoplankton blooms. We examined the variability of the free-living bacterioplankton at Helgoland Roads (German Bight, North Sea) over a period of one year with high temporal and taxonomic resolution to reveal variation patterns and main influencing factors. 16S rRNA gene tag sequencing of the bacterioplankton community hints at annual recurrence and resilience of few main taxa belonging to Alphaproteobacteria, Betaproteobacteria, Flavobacteriia, Acidimicrobiia and Thermoplasmata. Multiple regression analyses with various environmental factors revealed changes in water current patterns and resulting phytoplankton blooms as the main driving factors for short-term variation and temperature as the overlying factor for seasonal variation. Comparison of bacterioplankton successions during spring and summer phytoplankton blooms revealed the same dominating Flavobacteriia operational taxonomic units (OTUs) but shifts in Roseobacter related OTUs (Alphaproteobacteria) and SAR92 clade members (Gammaproteobacteria). Network analysis suggests that during spring and summer phytoplankton blooms temperature-dependent guilds are formed. In conclusion, our data imply that short-term bacterioplankton successions in response to phytoplankton blooms are indirectly affected by temperature, which is a major niche-defining factor in the German Bight. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Three-dimensional echocardiography: assessment of inter- and intra-operator variability and accuracy in the measurement of left ventricular cavity volume and myocardial mass

    Energy Technology Data Exchange (ETDEWEB)

    Nadkarni, S.K.; Drangova, M. [Advanced Imaging Research Laboratories, John P Robarts Research Institute, PO Box 5015, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); Department of Medical Biophysics, Medical Sciences Building, University of Western Ontario, London, Ontario N6A 5C1 (Canada); Boughner, D.R. [Department of Medical Biophysics, Medical Sciences Building, University of Western Ontario, London, Ontario N6A 5C1 (Canada); London Health Sciences Centre, University Campus. London, Ontario N6A 5A5 (Canada); Fenster, A. [Advanced Imaging Research Laboratories, John P Robarts Research Institute, PO Box 5015, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); Department of Medical Biophysics, Medical Sciences Building, University of Western Ontario, London, Ontario N6A 5C1 (Canada). E-mail: afenster at irus.rri.on.ca

    2000-05-01

    Accurate left ventricular (LV) volume and mass estimation is a strong predictor of cardiovascular morbidity and mortality. We propose that our technique of 3D echocardiography provides an accurate quantification of LV volume and mass by the reconstruction of 2D images into 3D volumes, thus avoiding the need for geometric assumptions. We compared the accuracy and variability in LV volume and mass measurement using 3D echocardiography with 2D echocardiography, using in vitro studies. Six operators measured the LV volume and mass of seven porcine hearts, using both 3D and 2D techniques. Regression analysis was used to test the accuracy of results and an ANOVA test was used to compute variability in measurement. LV volume measurement accuracy was 9.8% (3D) and 18.4% (2D); LV mass measurement accuracy was 5% (3D) and 9.2% (2D). Variability in LV volume quantification with 3D echocardiography was %SEM{sub inter} = 13.5%, %SEM{sub intra} = 11.4%, and for 2D echocardiography was %SEM{sub inter} = 21.5%, %SEM{sub intra} = 19.1%. We derived an equation to predict uncertainty in measurement of LV volume and mass using 3D echocardiography, the results of which agreed with our experimental results to within 13%. 3D echocardiography provided twice the accuracy for LV volume and mass measurement and half the variability for LV volume measurement as compared with 2D echocardiography. (author)

  7. Comparison of the trunk-pelvis and lower extremities sagittal plane inter-segmental coordination and variability during walking in persons with and without chronic low back pain.

    Science.gov (United States)

    Ebrahimi, Samaneh; Kamali, Fahimeh; Razeghi, Mohsen; Haghpanah, Seyyed Arash

    2017-04-01

    Inter-segmental coordination can be influenced by chronic low back pain (CLBP). The sagittal plane lower extremities inter-segmental coordination pattern and variability, in conjunction with the pelvis and trunk, were assessed in subjects with and without non-specific CLBP during free-speed walking. Kinematic data were collected from 10 non-specific CLBP and 10 non-CLBP control volunteers while the subjects were walking at their preferred speed. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis and bilateral pelvis-thigh, thigh-shank and shank-foot coordination pattern and variability over the stance and swing phases of gait. Mann-Whitney U test was employed to compare the means of DP and MARP values between two groups (same side comparison). Statistical analysis revealed more in-phase/less variable trunk-pelvis coordination in the CLBP group (Pfoot MARP values in the CLBP group, were more in-phase than left MARP values in the non-CLBP control group during the swing phase (Pplane lower extremities, pelvis and trunk coordination pattern and variability could be generally affected by CLBP during walking. These changes can be possible compensatory strategies of the motor control system which can be considered in the CLBP subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Three-dimensional echocardiography: assessment of inter- and intra-operator variability and accuracy in the measurement of left ventricular cavity volume and myocardial mass

    International Nuclear Information System (INIS)

    Nadkarni, S.K.; Drangova, M.; Boughner, D.R.; Fenster, A.; Department of Medical Biophysics, Medical Sciences Building, University of Western Ontario, London, Ontario N6A 5C1

    2000-01-01

    Accurate left ventricular (LV) volume and mass estimation is a strong predictor of cardiovascular morbidity and mortality. We propose that our technique of 3D echocardiography provides an accurate quantification of LV volume and mass by the reconstruction of 2D images into 3D volumes, thus avoiding the need for geometric assumptions. We compared the accuracy and variability in LV volume and mass measurement using 3D echocardiography with 2D echocardiography, using in vitro studies. Six operators measured the LV volume and mass of seven porcine hearts, using both 3D and 2D techniques. Regression analysis was used to test the accuracy of results and an ANOVA test was used to compute variability in measurement. LV volume measurement accuracy was 9.8% (3D) and 18.4% (2D); LV mass measurement accuracy was 5% (3D) and 9.2% (2D). Variability in LV volume quantification with 3D echocardiography was %SEM inter = 13.5%, %SEM intra = 11.4%, and for 2D echocardiography was %SEM inter = 21.5%, %SEM intra = 19.1%. We derived an equation to predict uncertainty in measurement of LV volume and mass using 3D echocardiography, the results of which agreed with our experimental results to within 13%. 3D echocardiography provided twice the accuracy for LV volume and mass measurement and half the variability for LV volume measurement as compared with 2D echocardiography. (author)

  9. Numerical simulation of inter-annual variations in the properties of the upper mixed layer in the Black Sea over the last 34 years

    Science.gov (United States)

    Shapiro, Georgy I.; Wobus, Fred; Zatsepin, Andrei G.; Akivis, Tatiana M.; Zanacchi, Marcus; Stanichny, Sergey

    2014-05-01

    The Black Sea is a nearly land-locked basin where a combination of salt and heat budgets results in a unique thermohaline water mass structure. An important feature of the Black Sea is that oxygen is dissolved and rich sea life made possible only in the upper water levels. This is due to a strong pycnocline which cannot be mixed even by strong winds or winter convection (Shapiro, 2008). The upper mixed layer (UML) with a nearly uniform temperature profile and a very sharp seasonal thermocline at its lower boundary develops during the summer season (Sur & Ilyin, 1997). The deepening of the UML has an important effect on the supply of nutrients into the euphotic upper layer from the underlying nutrient-rich water mass. The temperature of the UML at any given location is dependent on the surface heat flux, horizontal advection of heat, the depth and the rate of deepening of the UML. In this study we use a 3D ocean circulation model, NEMO-SHELF (O'Dea et al, 2012) to simulate the parameters of the UML in the Black Sea over the last 34 years. The model has horizontal resolution of 1/12×1/16 degrees and 33 layers in the vertical. The vertical discretization uses a hybrid enveloped s-z grid developed in Shapiro et al. (2012). The model is spun up from climatology (Suvorov et al., 2004); it is forced by the Drakkar Forcing Set v5.2 (Brodeau et al., 2010, Meinvielle et al., 2013) and river discharges from 8 major rivers are included. For each year the model is run from 1st January and the data for the period April to October are used for analysis. The sea surface temperature produced by the model is compared with satellite data ( Modis-Aqua, 2013) to show a good agreement. The model simulations are validated against in-situ observations (BSERP-3, 2004; Piotukh et al., 2011). The analysis is performed for the deep basin where the depth of the sea is greater than 1000m. It clearly shows the inter-annual variations of both the SST and the depth of UML. The depth of UML is

  10. Interannual and intra-annual variability of rainfall in Haiti (1905-2005)

    Science.gov (United States)

    Moron, Vincent; Frelat, Romain; Jean-Jeune, Pierre Karly; Gaucherel, Cédric

    2015-08-01

    The interannual variability of annual and monthly rainfall in Haiti is examined from a database of 78 rain gauges in 1905-2005. The spatial coherence of annual rainfall is rather low, which is partly due to Haiti's rugged landscape, complex shoreline, and surrounding warm waters (mean sea surface temperatures >27 °C from May to December). The interannual variation of monthly rainfall is mostly shaped by the intensity of the low-level winds across the Caribbean Sea, leading to a drier- (or wetter-) than-average rainy season associated with easterly (or westerly) anomalies, increasing (or decreasing) winds. The varying speed of low-level easterlies across the Caribbean basin may reflect at least four different processes during the year: (1) an anomalous trough/ridge over the western edge of the Azores high from December to February, peaking in January; (2) a zonal pressure gradient between Eastern Pacific and the tropical Northern Atlantic from May/June to September, with a peak in August (i.e. lower-than-average rainfall in Haiti is associated with positive sea level pressure anomalies over the tropical North Atlantic and negative sea level pressure anomalies over the Eastern Pacific); (3) a local ocean-atmosphere coupling between the speed of the Caribbean Low Level Jet and the meridional sea surface temperature (SST) gradient across the Caribbean basin (i.e. colder-than-average SST in the southern Caribbean sea is associated with increased easterlies and below-average rainfall in Haiti). This coupling is triggered when the warmest Caribbean waters move northward toward the Gulf of Mexico; (4) in October/November, a drier- (or wetter-) than-usual rainy season is related to an almost closed anticyclonic (or cyclonic) anomaly located ENE of Haiti on the SW edge of the Azores high. This suggests a main control of the interannual variations of rainfall by intensity, track and/or recurrence of tropical depressions traveling northeast of Haiti. During this period, the

  11. Inter-annual and geographical variations in the extent of bare ice and dark ice on the Greenland ice sheet derived from MODIS satellite images

    Directory of Open Access Journals (Sweden)

    Rigen eShimada

    2016-04-01

    Full Text Available Areas of dark ice have appeared on the Greenland ice sheet every summer in recent years. These are likely to have a great impact on the mass balance of the ice sheet because of their low albedo. We report annual and geographical variations in the bare ice and dark ice areas that appeared on the Greenland Ice Sheet from 2000 to 2014 by using MODIS satellite images. The July monthly mean of the extent of bare ice showed a positive trend over these 15 years, and large annual variability ranging from 89,975 km2 to 279,075 km2, 5% and 16% of the entire ice sheet, respectively. The extent of dark ice also showed a positive trend and varied annually, ranging from 3,575 km2 to 26,975 km2, 4% and 10% of the bare ice extent. These areas are geographically varied, and their expansion is the greatest on the western side, particularly the southwestern side of the ice sheet. The bare ice extent correlates strongly with the monthly mean air temperature in July, suggesting that the extent was determined by snow melt. The dark ice extent also correlates with the air temperature; however, the correlation is weaker. The dark ice extent further correlates negatively with solar radiation. This suggests that the extent of dark ice is not only controlled by snow melt on the ice, but also by changes in the surface structures of the bare ice surface, such as cryoconite holes, which are associated with impurities appearing on the ice surface.

  12. Inter-annual and geographical variations in the extent of bare ice and dark ice on the Greenland ice sheet derived from MODIS satellite images

    Science.gov (United States)

    Shimada, Rigen; Takeuchi, Nozomu; Aoki, Teruo

    2016-04-01

    Areas of dark ice have appeared on the Greenland ice sheet every summer in recent years. These are likely to have a great impact on the mass balance of the ice sheet because of their low albedo. We report annual and geographical variations in the bare ice and dark ice areas that appeared on the Greenland Ice Sheet from 2000 to 2014 by using MODIS satellite images. The July monthly mean of the extent of bare ice showed a positive trend over these 15 years, and large annual variability ranging from 89,975 km2 to 279,075 km2, 5% and 16% of the entire ice sheet, respectively. The extent of dark ice also showed a positive trend and varied annually, ranging from 3,575 km2 to 26,975 km2, 4% and 10% of the bare ice extent. These areas are geographically varied, and their expansion is the greatest on the western side, particularly the southwestern side of the ice sheet. The bare ice extent correlates strongly with the monthly mean air temperature in July, suggesting that the extent was determined by snow melt. The dark ice extent also correlates with the air temperature; however, the correlation is weaker. The dark ice extent further correlates negatively with solar radiation. This suggests that the extent of dark ice is not only controlled by snow melt on the ice, but also by changes in the surface structures of the bare ice surface, such as cryoconite holes, which are associated with impurities appearing on the ice surface.

  13. Leishmaniasis direct agglutination test: using pictorials as training materials to reduce inter-reader variability and improve accuracy.

    Directory of Open Access Journals (Sweden)

    Emily R Adams

    Full Text Available BACKGROUND: The Direct Agglutination Test (DAT has a high diagnostic accuracy and remains, in some geographical areas, part of the diagnostic algorithm for Visceral Leishmaniasis (VL. However, subjective interpretation of results introduces potential for inter-reader variation. We report an assessment of inter-laboratory agreement and propose a pictorial-based approach to standardize reading of the DAT. METHODOLOGY: In preparation for a comparative evaluation of immunochromatographic diagnostics for VL, a proficiency panel of 15 well-characterized sera, DAT-antigen from a single batch and common protocol was sent to nine laboratories in Latin-America, East-Africa and Asia. Agreement (i.e., equal titre or within 1 titer with the reading by the reference laboratory was computed. Due to significant inter-laboratory disagreement on-site refresher training was provided to all technicians performing DAT. Photos of training plates were made, and end-titres agreed upon by experienced users of DAT within the Visceral-Leishmaniasis Laboratory-Network (VL-LN. RESULTS: Pre-training, concordance in DAT results with reference laboratories was only 50%, although agreement on negative sera was high (94%. After refresher training concordance increased to 84%; agreement on negative controls increased to 98%. Variance in readings significantly decreased after training from 3.3 titres to an average of 1.0 titre (two-sample Wilcoxon rank-sum (Mann-Whitney test (z = -3,624 and p = 0.0003. CONCLUSION: The most probable explanation for disagreement was subjective endpoint reading. Using pictorials as training materials may be a useful tool to reduce disparity in results and promote more standardized reading of DAT, without compromising diagnostic sensitivity.

  14. Historical versus contemporary climate forcing on the annual nesting variability of loggerhead sea turtles in the Northwest Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Michael D Arendt

    Full Text Available A recent analysis suggested that historical climate forcing on the oceanic habitat of neonate sea turtles explained two-thirds of interannual variability in contemporary loggerhead (Caretta caretta sea turtle nest counts in Florida, where nearly 90% of all nesting by this species in the Northwest Atlantic Ocean occurs. Here, we show that associations between annual nest counts and climate conditions decades prior to nest counts and those conditions one year prior to nest counts were not significantly different. Examination of annual nest count and climate data revealed that statistical artifacts influenced the reported 31-year lag association with nest counts. The projected importance of age 31 neophytes to annual nest counts between 2020 and 2043 was modeled using observed nest counts between 1989 and 2012. Assuming consistent survival rates among cohorts for a 5% population growth trajectory and that one third of the mature female population nests annually, the 41% decline in annual nest counts observed during 1998-2007 was not projected for 2029-2038. This finding suggests that annual nest count trends are more influenced by remigrants than neophytes. Projections under the 5% population growth scenario also suggest that the Peninsular Recovery Unit could attain the demographic recovery criteria of 106,100 annual nests by 2027 if nest counts in 2019 are at least comparable to 2012. Because the first year of life represents only 4% of the time elapsed through age 31, cumulative survival at sea across decades explains most cohort variability, and thus, remigrant population size. Pursuant to the U.S. Endangered Species Act, staggered implementation of protection measures for all loggerhead life stages has taken place since the 1970s. We suggest that the 1998-2007 nesting decline represented a lagged perturbation response to historical anthropogenic impacts, and that subsequent nest count increases since 2008 reflect a potential recovery response.

  15. Historical versus Contemporary Climate Forcing on the Annual Nesting Variability of Loggerhead Sea Turtles in the Northwest Atlantic Ocean

    Science.gov (United States)

    Arendt, Michael D.; Schwenter, Jeffrey A.; Witherington, Blair E.; Meylan, Anne B.; Saba, Vincent S.

    2013-01-01

    A recent analysis suggested that historical climate forcing on the oceanic habitat of neonate sea turtles explained two-thirds of interannual variability in contemporary loggerhead (Caretta caretta) sea turtle nest counts in Florida, where nearly 90% of all nesting by this species in the Northwest Atlantic Ocean occurs. Here, we show that associations between annual nest counts and climate conditions decades prior to nest counts and those conditions one year prior to nest counts were not significantly different. Examination of annual nest count and climate data revealed that statistical artifacts influenced the reported 31-year lag association with nest counts. The projected importance of age 31 neophytes to annual nest counts between 2020 and 2043 was modeled using observed nest counts between 1989 and 2012. Assuming consistent survival rates among cohorts for a 5% population growth trajectory and that one third of the mature female population nests annually, the 41% decline in annual nest counts observed during 1998–2007 was not projected for 2029–2038. This finding suggests that annual nest count trends are more influenced by remigrants than neophytes. Projections under the 5% population growth scenario also suggest that the Peninsular Recovery Unit could attain the demographic recovery criteria of 106,100 annual nests by 2027 if nest counts in 2019 are at least comparable to 2012. Because the first year of life represents only 4% of the time elapsed through age 31, cumulative survival at sea across decades explains most cohort variability, and thus, remigrant population size. Pursuant to the U.S. Endangered Species Act, staggered implementation of protection measures for all loggerhead life stages has taken place since the 1970s. We suggest that the 1998–2007 nesting decline represented a lagged perturbation response to historical anthropogenic impacts, and that subsequent nest count increases since 2008 reflect a potential recovery response. PMID

  16. Assessing inter- and intra-individual cognitive variability in patients at risk for cognitive impairment: the case of minimal hepatic encephalopathy.

    Science.gov (United States)

    Bisiacchi, Patrizia; Cona, Giorgia; Tarantino, Vincenza; Schiff, Sami; Montagnese, Sara; Amodio, Piero; Capizzi, Giovanna

    2014-12-01

    Recent evidence reveals that inter- and intra-individual variability significantly affects cognitive performance in a number of neuropsychological pathologies. We applied a flexible family of statistical models to elucidate the contribution of inter- and intra-individual variables on cognitive functioning in healthy volunteers and patients at risk for hepatic encephalopathy (HE). Sixty-five volunteers (32 patients with cirrhosis and 33 healthy volunteers) were assessed by means of the Inhibitory Control Task (ICT). A Generalized Additive Model for Location, Scale and Shape (GAMLSS) was fitted for jointly modeling the mean and the intra-variability of Reaction Times (RTs) as a function of socio-demographic and task related covariates. Furthermore, a Generalized Linear Mixed Model (GLMM) was fitted for modeling accuracy. When controlling for the covariates, patients without minimal hepatic encephalopathy (MHE) did not differ from patients with MHE in the low-demanding condition, both in terms of RTs and accuracy. Moreover, they showed a significant decline in accuracy compared to the control group. Compared to patients with MHE, patients without MHE showed faster RTs and higher accuracy only in the high-demanding condition. The results revealed that the application of GAMLSS and GLMM models are able to capture subtle cognitive alterations, previously not detected, in patients' subclinical pathologies.

  17. The inter-observer reading variability in anti-nuclear antibodies indirect (ANA) immunofluorescence test: A multicenter evaluation and a review of the literature.

    Science.gov (United States)

    Rigon, A; Infantino, M; Merone, M; Iannello, G; Tincani, A; Cavazzana, I; Carabellese, N; Radice, A; Manfredi, M; Soda, P; Afeltra, A

    2017-12-01

    Recently there has been an increase demand for Computer-Aided Diagnosis (CAD) tools to support clinicians in the field of Indirect ImmunoFluorescence (IIF), as the novel digital imaging reading approach can help to overcome the reader subjectivity. Nevertheless, a large multicenter evaluation of the inter-observer reading variability in this field is still missing. This work fills this gap as we evaluated 556 consecutive samples, for a total of 1679 images, collected in three laboratories with IIF expertise using HEp-2 cell substrate (MBL) at 1:80 screening dilution according to conventional procedures. In each laboratory, the images were blindly classified by two experts into three intensity classes: positive, negative, and weak positive. Positive and weak positive ANA-IIF results were categorized by the predominant fluorescence pattern among six main classes. Data were pairwise analyzed and the inter-observer reading variability was measured by Cohen's kappa test, revealing a pairwise agreement little further away than substantial both for fluorescence intensity and for staining pattern recognition (k=0.602 and k=0.627, respectively). We also noticed that the inter-observer reading variability decreases when it is measured with respect to a gold standard classification computed on the basis of labels assigned by the three laboratories. These data show that laboratory agreement improves using digital images and comparing each single human evaluation to potential reference data, suggesting that a solid gold standard is essential to properly make use of CAD systems in routine work lab. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Comparison of Inter-Observer Variability and Diagnostic Performance of the Fifth Edition of BI-RADS for Breast Ultrasound of Static versus Video Images.

    Science.gov (United States)

    Youk, Ji Hyun; Jung, Inkyung; Yoon, Jung Hyun; Kim, Sung Hun; Kim, You Me; Lee, Eun Hye; Jeong, Sun Hye; Kim, Min Jung

    2016-09-01

    Our aim was to compare the inter-observer variability and diagnostic performance of the Breast Imaging Reporting and Data System (BI-RADS) lexicon for breast ultrasound of static and video images. Ninety-nine breast masses visible on ultrasound examination from 95 women 19-81 y of age at five institutions were enrolled in this study. They were scheduled to undergo biopsy or surgery or had been stable for at least 2 y of ultrasound follow-up after benign biopsy results or typically benign findings. For each mass, representative long- and short-axis static ultrasound images were acquired; real-time long- and short-axis B-mode video images through the mass area were separately saved as cine clips. Each image was reviewed independently by five radiologists who were asked to classify ultrasound features according to the fifth edition of the BI-RADS lexicon. Inter-observer variability was assessed using kappa (κ) statistics. Diagnostic performance on static and video images was compared using the area under the receiver operating characteristic curve. No significant difference was found in κ values between static and video images for all descriptors, although κ values of video images were higher than those of static images for shape, orientation, margin and calcifications. After receiver operating characteristic curve analysis, the video images (0.83, range: 0.77-0.87) had higher areas under the curve than the static images (0.80, range: 0.75-0.83; p = 0.08). Inter-observer variability and diagnostic performance of video images was similar to that of static images on breast ultrasonography according to the new edition of BI-RADS. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  19. Inter-annual trend of the primary contribution of ship emissions to PM2.5 concentrations in Venice (Italy): Efficiency of emissions mitigation strategies

    Science.gov (United States)

    Contini, Daniele; Gambaro, Andrea; Donateo, Antonio; Cescon, Paolo; Cesari, Daniela; Merico, Eva; Belosi, Franco; Citron, Marta

    2015-02-01

    Ships and harbour emissions are currently increasing, due to the increase of tourism and trade, with potential impact on global air pollution and climate. At local scale, in-port ship emissions influence air quality in coastal areas impacting on health of coastal communities. International legislations to reduce ship emissions, both at Worldwide and European levels, are mainly based on the use of low-sulphur content fuel. In this work an analysis of the inter-annual trends of primary contribution, ε, of tourist shipping to the atmospheric PM2.5 concentrations in the urban area of Venice has been performed. Measurements have been taken in the summer periods of 2007, 2009 and 2012. Results show a decrease of ε from 7% (±1%) in 2007 to 5% (±1%) in 2009 and to 3.5% (±1%) in 2012. The meteorological and micrometeorological conditions of the campaigns were similar. Tourist ship traffic during measurement campaigns increased, in terms of gross tonnage, of about 25.4% from 2007 to 2009 and of 17.6% from 2009 to 2012. The decrease of ε was associated to the effect of a voluntary agreement (Venice Blue Flag) for the use of low-sulphur content fuel enforced in the area between 2007 and 2009 and to the implementation of the 2005/33/CE Directive in 2010. Results show that the use of low-sulphur fuel could effectively reduce the impact of shipping to atmospheric primary particles at local scale. Further, voluntary agreement could also be effective in reducing the impact of shipping on local air quality in coastal areas.

  20. Seasonal and inter-annual variations in methyl mercury concentrations in zooplankton from boreal lakes impacted by deforestation or natural forest fires.

    Science.gov (United States)

    Garcia, Edenise; Carignan, Richard; Lean, David R S

    2007-08-01

    We compared the effects of natural and anthropogenic watershed disturbances on methyl mercury (MeHg) concentration in bulk zooplankton from boreal Shield lakes. MeHg in zooplankton was monitored for three years in nine lakes impacted by deforestation, in nine lakes impacted by wildfire, and in twenty lakes with undisturbed catchments. Lakes were sampled during spring, mid- and late summer. MeHg in zooplankton showed a seasonal trend: concentrations were the lowest in spring, then peaked in mid-summer and decreased in late summer. Over the three study years, MeHg concentrations observed in mid-summer in zooplankton from forest harvested lakes were significantly higher than in reference and fire-impacted lakes, whereas differences between these two groups of lakes were not significant. The pattern of distribution of MeHg in zooplankton during the different seasons paralleled that of dissolved organic carbon (DOC), which is known as a vector of Hg from watershed soils to lake water. Besides DOC, MeHg in zooplankton also showed a positive significant correlation with epilimnetic temperature and sulfate concentrations. An inter-annual decreasing trend in MeHg was observed in zooplankton from reference and fire-impacted lakes. In forest harvested lakes, however, MeHg concentrations remained higher and nearly constant over three years following the impact. Overall these results indicate that the MeHg pulse observed in zooplankton following deforestation by harvesting is relatively long-lived, and may have repercussions to the accumulation of MeHg along the food chain. Therefore, potential effects of deforestation on the Hg contamination of fish should be taken into account in forest management practices.

  1. Stereological estimation of nuclear volume in benign and malignant melanocytic lesions of the skin. Inter- and intraobserver variability of malignancy grading

    DEFF Research Database (Denmark)

    Sørensen, Flemming Brandt; Ottosen, P D

    1991-01-01

    tumors, the observer variability of estimates of nuclear vv is studied. Routinely processed, paraffin embedded tissue specimens from 22 malignant melanomas and nine benign melanocytic cutaneous lesions are retrospectively investigated. The sampling scheme for estimation of nuclear vv is easy to use...... and robust, with more than 85% of the associated observed variance explained by differences among different tumors. Inter- and intraobserver reproducibilities are high, showing correlation coefficients of .86 and .96, respectively, with slopes of the regression lines close to unity. It is concluded...

  2. ASSESSING INTRA- AND INTER-FIELD VARIABILITY OF CORN NITROGEN FERTILIZER NEED USING GROUND-BASED REFLECTANCE SENSORS

    Science.gov (United States)

    Since soil types within and between corn (Zea mays L.) fields can be highly variable, the amount of nitrogen (N) provided by those different soil types to support production can also be highly variable. Ideally, the amount of N fertilizer added during a given growing season should be both climate-se...

  3. Impact of inter-seasonal solar variability on the association of lower troposphere and cold point tropopause in the tropics: Observations using RO data from COSMIC

    Science.gov (United States)

    Kumar, V.; Dhaka, S. K.; Ho, Shu-Peng; Singh, Narendra; Singh, Vir; Reddy, K. K.; Chun, H.-Y.

    2017-12-01

    Association of lower tropospheric variations with the cold point tropopause (CPT) is examined on inter-seasonal basis over the tropical region (30°N-30°S) during 2007-2010 using COSMIC/FORMOST-3 Radio Occultation (RO) data. Temperature analyses for this association are shown over different regions of the globe having contrast topography namely over Western Pacific sector, Indian sector, and African sector. Correlation coefficient (r), taken as a measurement of association, show specific longitudinal differences between the lower troposphere (from 1 km to 5 km height) and the CPT. The northern and southern hemispheres show contrast coupling of temperature variation between lower tropospheric region and the CPT. Land and ocean effects are found to contribute in a different way to the correlation coefficient. Analyses show symmetrical structure of 'r' on both sides of the equator over the African region, as data include mostly land region on both side of equator. Data represent positive correlation (r 0.5) over 15°-20° latitudes on either side of the equator over the African region, suggesting strong hold of the inter-seasonal variation of solar diabatic heating influence over the tropic of Cancer and tropic of Capricorn. On the other hand, there is a contrast behaviour over the Indian region, 'r' is nearly negative ( - 1.0) each year in the southern hemisphere (SH) and positive ( 0.4) in the northern hemisphere (NH) with a maxima near tropic of Cancer. Western Pacific region is found to display a linear increase in 'r' from negative ( - 1.0) in SH to positive ( 0.8) in NH. In general, 'r' (positive) maximizes over the land region around 15°-20° latitudes, suggesting a control of in phase inter-seasonal solar heating on the coupling of boundary layer/lower troposphere and CPT region, whereas it turns negative over water body. Analyses suggest that variabilities in CPT over different regions of globe show significant inter-seasonal association with the lower

  4. Changes in seasonal and annual high-frequency air temperature variability in the Arctic from 1951 to 1990

    Science.gov (United States)

    Przybylak, Rajmund

    2002-07-01

    A detailed analysis of intraseasonal (within season) and interannual (between years) temperature variability for the whole Arctic for the period 1951-90 is provided. For this purpose four temperature variables were used: average (TMEAN), maximum (TMAX) and minimum (TMIN) temperatures, and the diurnal temperature range (DTR). The source data for the analysis were the daily TMAX and TMIN for ten stations representing almost all climatic regions in the Arctic. The methods of calculation of temperature variability were mostly taken from Plummer ([1996]; Australian Meteorological Magazine 45: 233). Thus the results presented for the Arctic can be fully compared with existing results for the other parts of the world (China, the former USSR, the USA and Australia).Regional trends in intraseasonal and interannual temperature variability were mixed and the majority of them were insignificant. Trends in intraseasonal variability were positive in the Norwegian Arctic and eastern Greenland and negative in the Canadian and Russian Arctic. Small increases in interannual variability for all temperature variables were observed annually in the Norwegian Arctic and eastern Greenland, and in the Canadian Arctic. These were largely a result of increases in winter and transitional seasons respectively. On the other hand, opposite tendencies, both on a seasonal and an annual basis, occurred in the Russian Arctic. Statistically significant negative trends in intraseasonal variability were noted mainly in the Canadian Arctic, whereas such trends in interannual variability were noted mainly in the Russian Arctic. The absence of significant changes in intraseasonal and interannual variability of TMEAN, TMAX, TMIN and DTR is additional evidence (besides the average temperature) that in the Arctic in the period 1951-90 no tangible manifestations of the greenhouse effect can be identified.

  5. Intra-annual variability of the radiocarbon content of corals from the Galapagos Islands

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.A. (Nuclear Physics Lab. GL-10, Dept of Physics, Univ. of Washington, Seattle, WA (United States) Geophysics Program AK-50, Univ. of Washington, Seattle, WA (United States)); Farwell, G.W.; Schmidt, F.H. (Nuclear Physics Lab. GL-10, Dept. of Physics, Univ. of Washington, Seattle, WA (United States)); Grootes, P.M. (Nuclear Physics Lab. GL-10, Dept. of Physics, Univ. of Washington, Seattle, WA (United States) Quatenary Isotope Lab. AK-60, Dept. of Geological Sciences, Univ. of Washington, Seattle, WA (United States)); Stuiver, M. (Quatenary Isotope Lab. AK-60, Dept. of Geological Sciences, Univ. of Washington, Seattle, WA (United States))

    1993-01-01

    The authors report AMS [sup 14]C measurements on sub annual samples of coral from the Galapagos Islands that span the period, 1970-1973. Both the major 1972 El Nino/Southern Oscillation event and intra-annual changes in regional upwelling of [sup 14]C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. These data show that the corals preserve a detailed record of past intra-annual variations of the [sup 14]C content of surface ocean water.

  6. The effect of manipulating root mean square window length and overlap on reliability, inter-individual variability, statistical significance and clinical relevance of electromyograms.

    Science.gov (United States)

    Mark Burden, Adrian; Lewis, Sandra Elizabeth; Willcox, Emma

    2014-12-01

    Numerous ways exist to process raw electromyograms (EMGs). However, the effect of altering processing methods on peak and mean EMG has seldom been investigated. The aim of this study was to investigate the effect of using different root mean square (RMS) window lengths and overlaps on the amplitude, reliability and inter-individual variability of gluteus maximus EMGs recorded during the clam exercise, and on the statistical significance and clinical relevance of amplitude differences between two exercise conditions. Mean and peak RMS of 10 repetitions from 17 participants were obtained using processing window lengths of 0.01, 0.15, 0.2, 0.25 and 1 s, with no overlap and overlaps of 25, 50 and 75% of window length. The effect of manipulating window length on reliability and inter-individual variability was greater for peak EMG (coefficient of variation [CV] window generally displaying the lowest variability. As a consequence, neither statistical significance nor clinical relevance (effect size [ES]) of mean EMG was affected by manipulation of window length. Statistical significance of peak EMG was more sensitive to changes in window length, with lower p-values generally being recorded for the 1 s window. As use of different window lengths has a greater effect on variability and statistical significance of the peak EMG, then clinicians should use the mean EMG. They should also be aware that use of different numbers of exercise repetitions and participants can have a greater effect on EMG parameters than length of processing window. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Hydroxyl layer: trend of number density and intra-annual variability

    Science.gov (United States)

    Sonnemann, G. R.; Hartogh, P.; Berger, U.; Grygalashvyly, M.

    2015-06-01

    The layer of vibrationally excited hydroxyl (OH*) near the mesopause in Earth's atmosphere is widely used to derive the temperature at this height and to observe dynamical processes such as gravity waves. The concentration of OH* is controlled by the product of atomic hydrogen, with ozone creating a layer of enhanced concentration in the mesopause region. However, the basic influences on the OH* layer are atomic oxygen and temperature. The long-term monitoring of this layer provides information on a changing atmosphere. It is important to know which proportion of a trend results from anthropogenic impacts on the atmosphere and which proportion reflects natural variations. In a previous paper (Grygalashvyly et al., 2014), the trend of the height of the layer and the trend in temperature were investigated particularly in midlatitudes on the basis of our coupled dynamic and chemical transport model LIMA (Leibniz Institute Middle Atmosphere). In this paper we consider the trend for the number density between the years 1961 and 2009 and analyze the reason of the trends on a global scale. Further, we consider intra-annual variations. Temperature and wind have the strongest impacts on the trend. Surprisingly, the increase in greenhouse gases (GHGs) has no clear influence on the chemistry of OH*. The main reason for this lies in the fact that, in the production term of OH*, if atomic hydrogen increases due to increasing humidity of the middle atmosphere by methane oxidation, ozone decreases. The maximum of the OH* layer is found in the mesopause region and is very variable. The mesopause region is a very intricate domain marked by changeable dynamics and strong gradients of all chemically active minor constituents determining the OH* chemistry. The OH* concentration responds, in part, very sensitively to small changes in these parameters. The cause for this behavior is given by nonlinear reactions of the photochemical system being a nonlinear enforced chemical oscillator

  8. Hydroxyl layer: trend of number density and intra-annual variability

    Directory of Open Access Journals (Sweden)

    G. R. Sonnemann

    2015-06-01

    Full Text Available The layer of vibrationally excited hydroxyl (OH* near the mesopause in Earth's atmosphere is widely used to derive the temperature at this height and to observe dynamical processes such as gravity waves. The concentration of OH* is controlled by the product of atomic hydrogen, with ozone creating a layer of enhanced concentration in the mesopause region. However, the basic influences on the OH* layer are atomic oxygen and temperature. The long-term monitoring of this layer provides information on a changing atmosphere. It is important to know which proportion of a trend results from anthropogenic impacts on the atmosphere and which proportion reflects natural variations. In a previous paper (Grygalashvyly et al., 2014, the trend of the height of the layer and the trend in temperature were investigated particularly in midlatitudes on the basis of our coupled dynamic and chemical transport model LIMA (Leibniz Institute Middle Atmosphere. In this paper we consider the trend for the number density between the years 1961 and 2009 and analyze the reason of the trends on a global scale. Further, we consider intra-annual variations. Temperature and wind have the strongest impacts on the trend. Surprisingly, the increase in greenhouse gases (GHGs has no clear influence on the chemistry of OH*. The main reason for this lies in the fact that, in the production term of OH*, if atomic hydrogen increases due to increasing humidity of the middle atmosphere by methane oxidation, ozone decreases. The maximum of the OH* layer is found in the mesopause region and is very variable. The mesopause region is a very intricate domain marked by changeable dynamics and strong gradients of all chemically active minor constituents determining the OH* chemistry. The OH* concentration responds, in part, very sensitively to small changes in these parameters. The cause for this behavior is given by nonlinear reactions of the photochemical system being a nonlinear enforced

  9. High inter-reviewer variability of spike detection on intracranial EEG addressed by an automated multi-channel algorithm.

    Science.gov (United States)

    Barkmeier, Daniel T; Shah, Aashit K; Flanagan, Danny; Atkinson, Marie D; Agarwal, Rajeev; Fuerst, Darren R; Jafari-Khouzani, Kourosh; Loeb, Jeffrey A

    2012-06-01

    The goal of this study was to determine the consistency of human reviewer spike detection and then develop a computer algorithm to make the intracranial spike detection process more objective and reliable. Three human reviewers marked interictal spikes on samples of intracranial EEGs from 10 patients. The sensitivity, precision and agreement in channel ranking by activity were calculated between reviewers. A computer algorithm was developed to parallel the way human reviewers detect spikes by first identifying all potential spikes on each channel using frequency filtering and then block scaling all channels at the same time in order to exclude potential spikes that fall below an amplitude and slope threshold. Its performance was compared to the human reviewers on the same set of patients. Human reviewers showed surprisingly poor inter-reviewer agreement, but did broadly agree on the ranking of channels for spike activity. The computer algorithm performed as well as the human reviewers and did especially well at ranking channels from highest to lowest spike frequency. Our algorithm showed good agreement with the different human reviewers, even though they demonstrated different criteria for what constitutes a 'spike' and performed especially well at the clinically important task of ranking channels by spike activity. An automated, objective method to detect interictal spikes on intracranial recordings will improve both research and the surgical management of epilepsy patients. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Exploring drug solubility in fasted human intestinal fluid aspirates: Impact of inter-individual variability, sampling site and dilution.

    Science.gov (United States)

    de la Cruz-Moreno, Mariangeles Pérez; Montejo, Consuelo; Aguilar-Ros, Antonio; Dewe, Walthère; Beck, Benoît; Stappaerts, Jef; Tack, Jan; Augustijns, Patrick

    2017-08-07

    One of the main factors defining intestinal drug absorption is the solubility of the compound in the gastrointestinal environment. This study reports the solubility of a series of 27 commonly used acidic, neutral and basic drugs in human intestinal fluid samples collected from the duodenum or jejunum of healthy volunteers under fasted state conditions. The interindividual variability as well as the impact of factors such as pH, sampling site and bile salts on the solubility in human intestinal fluids was investigated. The solubility measurements were evaluated using a statistical experimental design. Variability in solubility across volunteers and sampling sites was highly compound-specific and appeared to be substantial for weak acids and bases and for lipophilic drugs. Both pH of the samples and the abundance of amphiphilic components were responsible for the variability observed in the solubility values obtained. The results confirm strong interindividual differences in intraluminal solubility, especially for compounds with high lipophilicity and/or compounds with a pKa value within the physiological pH range. It is important to recognize this variability in intestinal drug solubility as it may considerably influence the therapeutic outcome among patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. MRI screening for silicone breast implant rupture: accuracy, inter- and intraobserver variability using explantation results as reference standard

    NARCIS (Netherlands)

    Maijers, M.C.; Niessen, F.B.; Veldhuizen, J.F.H.; Ritt, M.J.P.F.; Manoliu, R.A.

    2014-01-01

    Objectives: The recall of Poly Implant Prothèse (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study's aim was to assess the accuracy and interobserver variability of MRI screening in

  12. Intra- and Inter- annual PM2.5 variations in the Arctic region during 2003-2017 based on the NASA's MERRA-2 re-analysis data

    Science.gov (United States)

    Yasunari, T. J.; Kim, K. M.; da Silva, A. M., Jr.

    2017-12-01

    We examined the intra- and inter-annual variations of PM2.5 in the Arctic region based on monthly mean aerosols (dust, sulfate, sea salt, and carbonaceous aerosols) and PM2.5 from NASA's latest reanalysis, MERRA2. We focus on the time period from January 2003 to the recent month (May 2017). The domain of the Arctic region was defined as North of 66.5N in this study. Although there are some exceptions, the largest contributions of dust, ammonium sulfate, sea salt, and carbonaceous aerosols (i.e., Black Carbon, BC, and Particulate Organic Matter, POM) to the fractions of PM2.5 were mainly seen in spring, spring, fall, and summer, respectively. During the focused time period, the fractions of dust, ammonium sulfate, sea salt, BC, and POM explains 2.7-42.5%, 9.5-37.5%, 16.7-73.1%, 0.5-2.8%, 1.5-58.0% of the Arctic PM2.5, respectively. If we picked up the top 10 high PM2.5 months during the period, those were separated into two seasons: summer (eight months) and winter (two months). For the composites of the summer months above, the areas with higher PM2.5 were Siberia, Far East, Alaska, and Canada and the regions where POM fractions were larger, implying the contributions from smokes due to active wildfires in summer seasons. For the winter months, the mixture of increased dust, ammonium sulfate, and sea salt was seen. However, the highest PM2.5 in the Arctic region was seen from the Kara Sea, Barents Sea, and Greenland Sea over which the contribution of sea salt was very large. This means the sea salt aerosols were the main contributor to the high PM2.5 winter months there. Based on our MERRA-2 analyses, continuous monitoring and development for better forecasting wildfire activities in summer and sea salt emissions in winter would be the keys for better understanding of the air quality in the Arctic region including mitigation and measures of it in the future.

  13. Thoracic magnetic resonance venography using Gadofosveset in patients with venous pathology-A comparative study of image quality and inter-rater variability.

    Science.gov (United States)

    Åkesson, Michael; Lehti, Leena; Höglund, Peter; Åkeson, Per; Wassélius, Johan

    2017-08-01

    Background High-quality non-invasive imaging of the deep venous system in the thorax is challenging, but nevertheless required for diagnosis of vascular pathology as well as for patient selection and preoperative planning for endovascular procedures. Purpose To compare the diagnostic quality of Gadofosveset-enhanced thoracic magnetic resonance venography, seven consecutive patients with suspected or known disease affecting the central thoracic veins were compared to seven consecutive magnetic resonance venography using conventional gadolinium-based contrast agents. Materials and methods Diagnostic capability, defined as the ability to assess vessel patency and pathologic conditions, for the major thoracic deep venous segments was assessed by two-independent readers. Both reviewers rated the overall subjective image quality on a four-graded scale, and inter-rater variability was analyzed using unweighted and weighted Cohen's kappa values. Results Diagnostic capability was generally considerably higher in the Gadofosveset group for all examined vessel segments. The overall images quality rating was significantly higher for the Gadofosveset group with a mean rating of 2.9 and 2.7 for the two-independent readers, compared to 1.2 and 1.0 for the control croup. Inter-rater variability showed less variability for the Gadofosveset group with a quadratic-weighted Cohen's Kappa value of 0.58 compared to 0.36 for the control group. Conclusion Our results show that Gadofosveset-enhanced magnetic resonance venography of the central thoracic veins is a reliable technique in clinical routine practice that results in diagnostic images, superior to conventional gadolinium-based contrast medium.

  14. Assessing Seasonal and Inter-Annual Variations of Lake Surface Areas in Mongolia during 2000-2011 Using Minimum Composite MODIS NDVI.

    Science.gov (United States)

    Kang, Sinkyu; Hong, Suk Young

    2016-01-01

    A minimum composite method was applied to produce a 15-day interval normalized difference vegetation index (NDVI) dataset from Moderate Resolution Imaging Spectroradiometer (MODIS) daily 250 m reflectance in the red and near-infrared bands. This dataset was applied to determine lake surface areas in Mongolia. A total of 73 lakes greater than 6.25 km2in area were selected, and 28 of these lakes were used to evaluate detection errors. The minimum composite NDVI showed a better detection performance on lake water pixels than did the official MODIS 16-day 250 m NDVI based on a maximum composite method. The overall lake area detection performance based on the 15-day minimum composite NDVI showed -2.5% error relative to the Landsat-derived lake area for the 28 evaluated lakes. The errors increased with increases in the perimeter-to-area ratio but decreased with lake size over 10 km(2). The lake area decreased by -9.3% at an annual rate of -53.7 km(2) yr(-1) during 2000 to 2011 for the 73 lakes. However, considerable spatial variations, such as slight-to-moderate lake area reductions in semi-arid regions and rapid lake area reductions in arid regions, were also detected. This study demonstrated applicability of MODIS 250 m reflectance data for biweekly monitoring of lake area change and diagnosed considerable lake area reduction and its spatial variability in arid and semi-arid regions of Mongolia. Future studies are required for explaining reasons of lake area changes and their spatial variability.

  15. Inter-individual variability in the oxidation of 1,2-dibromoethane: use of heterologously expressed human cytochrome P450 and human liver microsomes.

    Science.gov (United States)

    Wormhoudt, L W; Ploemen, J H; de Waziers, I; Commandeur, J N; Beaune, P H; van Bladeren, P J; Vermeulen, N P

    1996-09-06

    1,2-Dibromoethane (1,2-DBE) is mainly used as an additive in leaded gasoline and as a soil fumigant and it is a suspected carcinogen in humans. In this study, the oxidative bioactivation of 1,2-DBE to 2-bromoacetaldehyde (2-BA) was studied using heterologously expressed human cytochrome P450 (P450) isoenzymes and human liver microsomes. Out of ten heterologously expressed human P450 isoenzymes (CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2E1, CYP2C8, CYP2C9, CYP2C18, CYP3A4 and CYP3A5), only human CYP2A6, CYP2B6 and CYP2E1 metabolized 1,2-DBE, albeit with strongly differing catalytic efficiencies. The apparent Km and Vmax values were 3.3 mM and 0.17 pmol/min per pmol P450 for CYP2A6, 9.7 mM and 3.18 pmol/min per pmol P450 for CYP2B6 and 42 microM and 1.3 pmol/min per pmol P450 for CYP2E1, respectively. In all of 21 human liver samples studied, 1,2-DBE was oxidized with activities ranging from 22.2 to 1027.6 pmol/min per mg protein, thus showing a 46-fold inter-individual variability. The kinetics of the oxidative metabolism of 1,2-DBE to 2-BA in human liver microsomes were linear, indicating the involvement of primarily one single P450 isoenzyme. There was a tendency towards a positive correlation between the oxidative metabolism of 1,2-DBE in the human liver microsomes and the 6-hydroxylation of chlorzoxazone, a selective substrate for CYP2E1. Furthermore, the oxidative metabolism of 1,2-DBE was inhibited by the specific CYP2E1 inhibitors disulfiram (DS) and diethyldithiocarbamate (DDC). In contrast, a poor correlation was found between the immunochemically quantified amount of CYP2E1 and the microsomal chlorzoxazone 6-hydroxylation or the 1,2-DBE oxidation. The results indicate that CYP2E1 is probably the major P450 isoenzyme involved in the oxidative hepatic metabolism of 1,2-DBE in humans. The inter-individual variability in the oxidative bioactivation of 1,2-DBE in humans, largely due to inter-individual variability in the catalytic activity of hepatic CYP2E1, may have

  16. The annual cycle of African climate and its variability | Jury | Water SA

    African Journals Online (AJOL)

    A statistical analysis of African rainfall and temperature, and surface wind components and sea level pressure over the tropical Atlantic and Indian Oceans is done in the period 1965 to 1995. The annual cycle is found to be the dominant mode, exhibiting a subtropical north - south dipole with a cycle period of 12 months.

  17. Variability of seasonal and annual precipitation in Slovenia and its correlation with large-scale atmospheric circulation

    Directory of Open Access Journals (Sweden)

    Milošević Dragan D.

    2016-01-01

    Full Text Available This paper examines temporal and spatial variability and trends of annual and seasonal precipitation in Slovenia and their relationship with three atmospheric circulation patterns represented by their indices: North Atlantic Oscillation index (NAOi, Mediterranean Oscillation index (MOi andWestern Mediterranean Oscillation index (WeMOi. Data from 45 precipitation stations were used for the period 1963–2012.Mean annual precipitation varies from 736 mm in eastern Slovenia to 2,518 mm in northwestern Slovenia. A significant annual precipitation decrease (from −3% to −6% per decade is observed in western Slovenia. Significant negative trends are observed in southwestern Slovenia in summer (from −4% to −10% per decade and near the Adriatic coast in spring (from −6% to −10% per decade. Non-significant negative and positive trends are observed in winter and autumn, respectively. Results indicate significant correlations between winter precipitation and MOi (from −0.3 to −0.7, NAOi (from −0.3 to −0.6 andWeMOi (from 0.3 to 0.6. Significant We-MOi influence is observed in spring and autumn, while NAOi and MOi influence has not been detected. Annual precipitation and WeMOi are significantly correlated in central and eastern Slovenia, while significant NAOi and MOi influence is observed in western Slovenia (with the larger area covered by MOi influence.

  18. Effect of inter-reader variability on outcomes in studies using carotid intima media thickness quantified by carotid ultrasonography.

    Science.gov (United States)

    Delaney, Joseph A C; Scherzer, Rebecca; Polak, Joseph; Biggs, Mary Lou; Kronmal, Richard; Chen, Haiying; Sidney, Stephen; Grunfeld, Carl

    2010-06-01

    Systematic differences between readers or equipment in imaging studies are not uncommon; failure to account for such differences when using Carotid Ultrasonography may introduce bias into associations between carotid intima media thickness (cIMT) and outcomes. We demonstrate the impact of this source of systematic measurement error (SME) using data on 5,521 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) and 661 participants from the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM). Participants were between 37 and 78 years old. Two outcomes were considered: (1) the effect of HIV infection on cIMT (between study) and (2) the association of cIMT with cardiovascular events (within study). All estimates were adjusted for demographics (age, gender, and ethnicity) and for traditional cardiovascular disease risk factors (smoking, blood pressure, diabetes and cholesterol). When comparing the FRAM and MESA cohorts to estimate the association of HIV infection on common cIMT, accounting for machine and reader variability (between study variability) reduced the difference associated with HIV infection from +0.080 mm (95% Confidence Interval (CI):0.065-0.095) to +0.037 mm (95% CI:0.003 to 0.072) while internal cIMT declined from +0.254 mm (95% CI:0.205-0.303) to +0.192 mm (95% CI:0.076-0.308). Attenuation of the association between cIMT and cardiovascular endpoints occurred when within study reader variability was not accounted for. The effect of SME due to use of multiple readers or machines is most important when comparisons are made between two different study populations. Within-cohort measurement error dilutes the association with events.

  19. One year variability of peak heights, heterozygous balance and inter-locus balance for the DNA positive control of AmpFℓSTR© Identifiler© STR kit.

    Science.gov (United States)

    Debernardi, A; Suzanne, E; Formant, A; Pène, L; Dufour, A B; Lobry, J R

    2011-01-01

    Multivariate analyses of 205 positive control experiments in an AmpFℓSTR© Identifiler© STR kit were used to analyze the factors affecting peak heights at 16 loci. Peak heights were found to be highly correlated between loci and there was evidence for a difference in sensitivity of the two genetic analyzers in the blue channel. Heterozygous balance response at 10 loci was found to behave as a random variable following a beta-distribution with typical median values of 90%, without locus or genetic analyzer effect. Inter-locus balance at 16 loci was influenced by the blue channel effect and a temporal switch of unexplained origin. The implications of these results for the choice of minimum threshold values in quality control are discussed. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Accuracy and inter-observer variability of 3D versus 4D cone-beam CT based image-guidance in SBRT for lung tumors

    Directory of Open Access Journals (Sweden)

    Sweeney Reinhart A

    2012-06-01

    Full Text Available Abstract Background To analyze the accuracy and inter-observer variability of image-guidance (IG using 3D or 4D cone-beam CT (CBCT technology in stereotactic body radiotherapy (SBRT for lung tumors. Materials and methods Twenty-one consecutive patients treated with image-guided SBRT for primary and secondary lung tumors were basis for this study. A respiration correlated 4D-CT and planning contours served as reference for all IG techniques. Three IG techniques were performed independently by three radiation oncologists (ROs and three radiotherapy technicians (RTTs. Image-guidance using respiration correlated 4D-CBCT (IG-4D with automatic registration of the planning 4D-CT and the verification 4D-CBCT was considered gold-standard. Results were compared with two IG techniques using 3D-CBCT: 1 manual registration of the planning internal target volume (ITV contour and the motion blurred tumor in the 3D-CBCT (IG-ITV; 2 automatic registration of the planning reference CT image and the verification 3D-CBCT (IG-3D. Image quality of 3D-CBCT and 4D-CBCT images was scored on a scale of 1–3, with 1 being best and 3 being worst quality for visual verification of the IGRT results. Results Image quality was scored significantly worse for 3D-CBCT compared to 4D-CBCT: the worst score of 3 was given in 19 % and 7.1 % observations, respectively. Significant differences in target localization were observed between 4D-CBCT and 3D-CBCT based IG: compared to the reference of IG-4D, tumor positions differed by 1.9 mm ± 0.9 mm (3D vector on average using IG-ITV and by 3.6 mm ± 3.2 mm using IG-3D; results of IG-ITV were significantly closer to the reference IG-4D compared to IG-3D. Differences between the 4D-CBCT and 3D-CBCT techniques increased significantly with larger motion amplitude of the tumor; analogously, differences increased with worse 3D-CBCT image quality scores. Inter-observer variability was largest in SI direction and was

  1. Pharmacological characterization of the bradykinin B2 receptor: inter-species variability and dissociation between binding and functional responses.

    Science.gov (United States)

    Paquet, J L; Luccarini, J M; Fouchet, C; Defrêne, E; Loillier, B; Robert, C; Bélichard, P; Cremers, B; Pruneau, D

    1999-03-01

    and native bradykinin B2 receptor in human (pKi of 8.66 and 8.59, respectively) and in rat (pKi 9.67 and 9.81, respectively). 6. In conclusion, we suggest that the binding buffer composition has to be taken into account when screening new compounds and that inter-species differences should be considered when setting up animal models with the aim of developing bradykinin B2 receptor antagonists as therapeutic agents.

  2. Anisotropic finite element models for brain injury prediction: the sensitivity of axonal strain to white matter tract inter-subject variability.

    Science.gov (United States)

    Giordano, Chiara; Zappalà, Stefano; Kleiven, Svein

    2017-08-01

    Computational models incorporating anisotropic features of brain tissue have become a valuable tool for studying the occurrence of traumatic brain injury. The tissue deformation in the direction of white matter tracts (axonal strain) was repeatedly shown to be an appropriate mechanical parameter to predict injury. However, when assessing the reliability of axonal strain to predict injury in a population, it is important to consider the predictor sensitivity to the biological inter-subject variability of the human brain. The present study investigated the axonal strain response of 485 white matter subject-specific anisotropic finite element models of the head subjected to the same loading conditions. It was observed that the biological variability affected the orientation of the preferential directions (coefficient of variation of 39.41% for the elevation angle-coefficient of variation of 29.31% for the azimuth angle) and the determination of the mechanical fiber alignment parameter in the model (gray matter volume 55.55-70.75%). The magnitude of the maximum axonal strain showed coefficients of variation of 11.91%. On the contrary, the localization of the maximum axonal strain was consistent: the peak of strain was typically located in a 2 cm 3 volume of the brain. For a sport concussive event, the predictor was capable of discerning between non-injurious and concussed populations in several areas of the brain. It was concluded that, despite its sensitivity to biological variability, axonal strain is an appropriate mechanical parameter to predict traumatic brain injury.

  3. The inter-observer variability of breast density scoring between mammography technologists and breast radiologists and its effect on the rate of adjuvant ultrasound.

    Science.gov (United States)

    Mazor, Roei D; Savir, Avital; Gheorghiu, David; Weinstein, Yuliana; Abadi-Korek, Ifat; Shabshin, Nogah

    2016-05-01

    This study assesses the inter-observer variability of mammographic breast density scoring (BDS) between technologists and radiologists and evaluates the effect of technologist patient referral on the load of adjuvant ultrasounds. In this IRB approved study, a retrospective analysis of 503 prospectively acquired, random mammograms was performed between January and March 2014. Each mammogram was evaluated for BDS independently and blindly by both the performing technologist and the interpreting radiologist. Statistical calculation of the Spearman correlation coefficient and weighted kappa were obtained to evaluate the inter-observer variability between technologists and radiologists and to examine whether it relates to the technologist's seniority or women's age. The effect on the load of adjuvant ultrasounds was evaluated. 10 mammography technologists and 7 breast radiologists participated in this study. BDS agreement levels between technologists and radiologists were in the fair to moderate range (kappa values: 0.3-0.45, Spearman coefficient values: 0.59-0.65). The technologists markedly over-graded the density compared to the radiologists in all the subsets evaluated. Comparison between low and high-density groups demonstrated a similar trend of over-grading by technologists, who graded 51% of the women as having dense breasts (scores 3-4) compared to 27% of the women graded as such by the radiologists. This trend of over grading breast density by technologists was unrelated to the women's age or to the technologists' seniority. Mammography technologists over-grade breast density. Technologists' referral to an adjuvant ultrasound leads to redundant ultrasound studies, unnecessary breast biopsies, costs and increased patient anxiety. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Inter-sport variability of muscle volume distribution identified by segmental bioelectrical impedance analysis in four ball sports

    Directory of Open Access Journals (Sweden)

    Yamada Y

    2013-04-01

    Full Text Available Yosuke Yamada,1,2 Yoshihisa Masuo,3 Eitaro Nakamura,4 Shingo Oda5 1Laboratory of Sports and Health Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; 2Japan Society for the Promotion of Science, Tokyo, Japan; 3Waseda University Research Institute for Elderly Health, Saitama, Japan; 4Department of Sport Science, Kyoto Iken College of Medicine and Health, Kyoto, Japan; 5Faculty of Health and Well-being, Kansai University, Osaka, Japan Abstract: The aim of this study was to evaluate and quantify differences in muscle distribution in athletes of various ball sports using segmental bioelectrical impedance analysis (SBIA. Participants were 115 male collegiate athletes from four ball sports (baseball, soccer, tennis, and lacrosse. Percent body fat (%BF and lean body mass were measured, and SBIA was used to measure segmental muscle volume (MV in bilateral upper arms, forearms, thighs, and lower legs. We calculated the MV ratios of dominant to nondominant, proximal to distal, and upper to lower limbs. The measurements consisted of a total of 31 variables. Cluster and factor analyses were applied to identify redundant variables. The muscle distribution was significantly different among groups, but the %BF was not. The classification procedures of the discriminant analysis could correctly distinguish 84.3% of the athletes. These results suggest that collegiate ball game athletes have adapted their physique to their sport movements very well, and the SBIA, which is an affordable, noninvasive, easy-to-operate, and fast alternative method in the field, can distinguish ball game athletes according to their specific muscle distribution within a 5-minute measurement. The SBIA could be a useful, affordable, and fast tool for identifying talents for specific sports. Keywords: discriminant analysis, cluster and factor analysis, segmental bioelectrical impedance analysis, baseball, lacrosse

  5. MRI screening for silicone breast implant rupture: accuracy, inter- and intraobserver variability using explantation results as reference standard

    Energy Technology Data Exchange (ETDEWEB)

    Maijers, M.C.; Ritt, M.J.P.F. [VU University Medical Centre, Department of Plastic, Reconstructive and Hand Surgery, De Boelelaan 1117, PO Box 7057, Amsterdam (Netherlands); Niessen, F.B. [VU University Medical Centre, Department of Plastic, Reconstructive and Hand Surgery, De Boelelaan 1117, PO Box 7057, Amsterdam (Netherlands); Jan van Goyen Clinic, Department of Plastic Surgery, Amsterdam (Netherlands); Veldhuizen, J.F.H. [MRI Centre, Amsterdam (Netherlands); Manoliu, R.A. [MRI Centre, Amsterdam (Netherlands); VU University Medical Centre, Department of Radiology, Amsterdam (Netherlands)

    2014-06-15

    The recall of Poly Implant Prothese (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study's aim was to assess the accuracy and interobserver variability of MRI screening in the detection of rupture and extracapsular silicone leakage. A prospective study included 107 women with 214 PIP implants who underwent explantation preceded by MRI. In 2013, two radiologists blinded for previous MRI findings or outcome at surgery, independently re-evaluated all MRI examinations. A structured protocol described the MRI findings. The ex vivo findings served as reference standard. In 208 of the 214 explanted prostheses, radiologists agreed independently about the condition of the implants. In five of the six cases they disagreed (2.6 %), but subsequently reached consensus. A sensitivity of 93 %, specificity of 93 %, positive predictive value of 77 % and negative predictive value of 98 % was found. The interobserver agreement was excellent (kappa value of 0.92). MRI has a high accuracy in diagnosing rupture in silicone breast implants. Considering the high kappa value of interobserver agreement, MRI appears to be a consistent diagnostic test. A simple, uniform classification, may improve communication between radiologist and plastic surgeon. (orig.)

  6. MRI screening for silicone breast implant rupture: accuracy, inter- and intraobserver variability using explantation results as reference standard

    International Nuclear Information System (INIS)

    Maijers, M.C.; Ritt, M.J.P.F.; Niessen, F.B.; Veldhuizen, J.F.H.; Manoliu, R.A.

    2014-01-01

    The recall of Poly Implant Prothese (PIP) silicone breast implants in 2010 resulted in large numbers of asymptomatic women with implants who underwent magnetic resonance imaging (MRI) screening. This study's aim was to assess the accuracy and interobserver variability of MRI screening in the detection of rupture and extracapsular silicone leakage. A prospective study included 107 women with 214 PIP implants who underwent explantation preceded by MRI. In 2013, two radiologists blinded for previous MRI findings or outcome at surgery, independently re-evaluated all MRI examinations. A structured protocol described the MRI findings. The ex vivo findings served as reference standard. In 208 of the 214 explanted prostheses, radiologists agreed independently about the condition of the implants. In five of the six cases they disagreed (2.6 %), but subsequently reached consensus. A sensitivity of 93 %, specificity of 93 %, positive predictive value of 77 % and negative predictive value of 98 % was found. The interobserver agreement was excellent (kappa value of 0.92). MRI has a high accuracy in diagnosing rupture in silicone breast implants. Considering the high kappa value of interobserver agreement, MRI appears to be a consistent diagnostic test. A simple, uniform classification, may improve communication between radiologist and plastic surgeon. (orig.)

  7. Relationship between annual precipitation variability and ENSO in Southern California for the Common Era (last 2,000 years)

    Science.gov (United States)

    DU, X.; Hendy, I. L.; Hinnov, L.; Brown, E. T.; Schimmelmann, A.; Pak, D. K.

    2017-12-01

    The El Niño-Southern Oscillation (ENSO) has a major influence on Southern California's hydroclimate as demonstrated by both historical observations and model simulations. Santa Barbara Basin (SBB) off Southern California preserves a unique varved (i.e. annually laminated) marine sedimentary archive of modern and Holocene hydroclimate variability, notably including the transition from the regionally dry Medieval Climate Anomaly (MCA) to the wetter Little Ice Age (LIA). Here we present sub-annually resolved scanning XRF elemental counts for the last 2,000 years in SBB from core SPR0901-03KC. Titanium (associated with silicate minerals) is delivered more efficiently to SBB sediments during times of enhanced river flow and in the Mediterranean climate of Southern California, river flow only occurs after precipitation. The Ti record suggests that the precipitation frequency was reduced during the MCA except for a pluvial episode at CE 1075-1121, but increased during the LIA. Time series analysis of Ti counts indicates ENSO variability robustly increased during the intervals CE 450-520, 650-720, 980-1150, 1380-1550 and 1720-1750, and experienced relatively quiescent intervals between CE 50-150, 250-400, 550-650, 750-950, 1150-1280 and 1580-1620. Generally the LIA in Southern California is characterized by more active ENSO variability with long periodicities (4-7 yr) and multi-decadal variability (54 yr). MCA drought episodes were associated with less active ENSO. Active ENSO variability in Southern California during the last 2,000 years coincided with reconstructed southward migration of the Intertropical Convergence Zone (ITCZ) suggesting the ITCZ may play a role in the waxing and waning of ENSO teleconnections between the central Pacific and the west coast of North America.

  8. Multi-annual modes in the 20th century temperature variability in reanalyses and CMIP5 models

    Directory of Open Access Journals (Sweden)

    H. Järvinen

    2016-11-01

    Full Text Available A performance expectation is that Earth system models simulate well the climate mean state and the climate variability. To test this expectation, we decompose two 20th century reanalysis data sets and 12 CMIP5 model simulations for the years 1901–2005 of the monthly mean near-surface air temperature using randomised multi-channel singular spectrum analysis (RMSSA. Due to the relatively short time span, we concentrate on the representation of multi-annual variability which the RMSSA method effectively captures as separate and mutually orthogonal spatio-temporal components. This decomposition is a unique way to separate statistically significant quasi-periodic oscillations from one another in high-dimensional data sets.The main results are as follows. First, the total spectra for the two reanalysis data sets are remarkably similar in all timescales, except that the spectral power in ERA-20C is systematically slightly higher than in 20CR. Apart from the slow components related to multi-decadal periodicities, ENSO oscillations with approximately 3.5- and 5-year periods are the most prominent forms of variability in both reanalyses. In 20CR, these are relatively slightly more pronounced than in ERA-20C. Since about the 1970s, the amplitudes of the 3.5- and 5-year oscillations have increased, presumably due to some combination of forced climate change, intrinsic low-frequency climate variability, or change in global observing network. Second, none of the 12 coupled climate models closely reproduce all aspects of the reanalysis spectra, although some models represent many aspects well. For instance, the GFDL-ESM2M model has two nicely separated ENSO periods although they are relatively too prominent as compared with the reanalyses. There is an extensive Supplement and YouTube videos to illustrate the multi-annual variability of the data sets.

  9. Inter-Colony Fidelity of Sr/Ca Variability in the Massive Caribbean Coral Siderastrea siderea: a Sub-Fossil Example

    Science.gov (United States)

    Maupin, C. R.; Quinn, T. M.; Poore, R. Z.; Lin, K.; Shen, C.

    2008-12-01

    Coral-based reconstructions of climate variability in the Atlantic Warm Pool (AWP) in the pre-instrumental period are sparse. Multi-century Sr/Ca records generated from the skeleton of the widely distributed, massive, slow growing (~0.5 cm yr-1) coral Siderastrea siderea have the potential to address this data gap by providing robust proxies of interannual- to centennial-scale sea surface temperature (SST) variability in the AWP. However, before modern and fossil geochemical time series from S. siderea can be interpreted in terms of climate variability, reproducibility tests must be performed on individual coral colonies from the same location. Here we provide one such assessment of inter-colony reproducibility in the geochemistry of S. siderea using cores from the Dry Tortugas National Park (~24°33'N, 82°53'W). Time series of Sr/Ca from a large colony cored live in the summer of 1993 and a second, sub-fossil colony core, with a high-precision mass spectrometric U/Th date of 110 ± 1.7 (2σ) yrs, are compared. The 25-year overlap exhibits excellent reproducibility in both monthly and monthly anomaly space, and the average absolute difference between monthly data from the two time series is within instrumental precision. The results of this work suggest that individual monthly Sr/Ca records from S. siderea can be deemed representative of local SST variability, and that continuous local Sr/Ca records can be successfully spliced together from living and sub-fossil corals using high precision U/Th dating.

  10. Low frequency variability of the Indian Ocean from TOPEX/POSEIDON sea surface height anomalies

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, Y.K.; Murty, V.S.N.; Sarma, Y.V.B.

    and off Sumatra present large variability on both seasonal and inter-annual time scales. The SSH anomalies off Sumatra show dominant influence of warm (cold) ENSO events with peak negative (positive) anomalies coinciding with El Nino (La Nina...

  11. Variabilities in CO2 and CO over an urban site in India: Inter-correlations and emissions characteristics.

    Science.gov (United States)

    Negi, N. C.; Lal, S.; Sethuraman, V.; Patra, P. K.

    2015-12-01

    CO2, the most important greenhouse gas (GHG) in the atmosphere, plays a pivotal role in climate change. The long term increase in its atmospheric abundance after the Industrial Revolution is attributed to the emissions from anthropogenic activities, especially fossil fuel combustion. CO is a product of inefficient combustion and can be used as a surrogate tracer for identifying the anthropogenic and biospheric signal of CO2 from the atmospheric observation. India is the second largest populous country in the world and share significant contribution in the emissions of greenhouse gases mainly CO2. The budget of CO2, estimated from top-down and bottom-up approaches, shows large uncertainties over the South Asian region than other continents. One of the major sources of these large uncertainties is the lack of spatial and temporal observations. An attempt has been made using a year-long period to study the variability of the levels of CO2 and CO at an urban site Ahmedabad (23.03oN, 72.58oE, 55m AMSL), in the western India using a highly sensitive cavity ring down spectroscopy technique. The diurnal cycles of CO2 and CO show distinct features to each other due to their diverse sources and sinks. Two significant peaks during the morning and evening hours have been observed in the diurnal cycle of CO2 while in the case of CO evening peak is significantly higher than the morning peak. The afternoon levels of CO2 are observed lower during monsoon, which shows the significant uptake of CO2 from the biosphere during this season. The diurnal amplitude of CO2 is found largest around 41 ppmv in autumn and lowest around 12 ppmv in monsoon. The seasonal cycles calculated from the afternoon average monthly CO2 show the minimum levels during monsoon and maximum during spring. In case of CO minimum levels are observed in monsoon while maximum are observed in winter. The seasonal amplitude is observed around 15.02 ppmv and 0.27 ppmv for CO2 and CO respectively. Further, the co

  12. Intra- and inter-individual variability of Aspergillus fumigatus reactive T-cell frequencies in healthy volunteers in dependency of mould exposure in residential and working environment.

    Science.gov (United States)

    Wurster, Sebastian; Weis, Philipp; Page, Lukas; Helm, Johanna; Lazariotou, Maria; Einsele, Hermann; Ullmann, Andrew J

    2017-10-01

    Invasive aspergillosis remains a deadly disease in immunocompromised patients, whereas the combination of an exaggerated immune response and continuous exposure lead to various hyperinflammatory diseases. This pilot study aimed to gain an overview of the intra- and inter-individual variability in Aspergillus fumigatus reactive T-helper cells in healthy adults and the correlation with environmental mould exposure. In this flow cytometric study, the frequencies of CD154 + A. fumigatus reactive T cells were evaluated in 70 healthy volunteers. All subjects completed a standardised questionnaire addressing their mould exposure. Subjects with intensive mould exposure in their professional or residential surrounding demonstrated considerably higher mean frequencies of A. fumigatus reactive T-helper and T-memory cells. Comparative evaluation of multiple measurements over time demonstrated relatively conserved reactive T-cell frequencies in the absence of major changes to the exposure profile, whereas those frequently exposed in professional environment or with changes to their risk score demonstrated a marked dependency of antigen reactive T-cell frequencies on recent mould exposure. This pilot study was the first to provide data on the intra-individual variability in A. fumigatus reactive T-cell frequencies and its linkage to mould encounter. Fungus reactive T cells are to be considered a valued tool for the assessment of environmental mould exposure. © 2017 Blackwell Verlag GmbH.

  13. Quantitative assessment of inter-clinician variability of target volume delineation for medulloblastoma: quality assurance for the SIOP PNET 4 trial protocol

    International Nuclear Information System (INIS)

    Coles, Charlotte E.; Hoole, Andrew C.F.; Harden, Susan V; Burnet, Neil G.; Twyman, Nicola; Taylor, Roger E.; Kortmann, Rolf D.; Williams, Michael V.

    2003-01-01

    Background and purpose: To assess inter-clinician variability amongst specialist paediatric radiation oncologists in delineating clinical target volumes for treating medulloblastoma as a quality assurance exercise prior to the introduction of the SIOP PNET 4 trial protocol of conformal radiotherapy to the posterior fossa and tumour bed. Patients and methods: Participants from 17 UK centres attended an educational meeting and then completed a clinical planning exercise to outline: (1) the whole posterior fossa and (2) the tumour bed. Quantitative analysis of the volumes, lengths, spatial positioning and axial planes for each individual was carried out and variation between individuals analysed. Results: Outlining of the posterior fossa was reasonably consistent, although most variation was seen in defining the superior border of the tentorium. A major difference was the decision whether or not to include the post-surgical meningocoele in the clinical target volume (CTV). The CTV for the tumour bed was under treated by all participants due to lack of inclusion of pre-operative tumour extent. Conclusions: This exercise demonstrated several ambiguities in the draft protocol and highlighted particular areas of inter-clinician variation. Consequently the protocol was revised and improved to take account of these findings. We recommend that planning exercises, in conjunction with education and training, should be implemented before the start of any new radiotherapy trial. In the future, the use of image transfer will allow prospective peer review of target volumes before treatment commences. These measures are essential to ensure that alterations in clinical practice are achieved in a uniform way

  14. Impact of acquisition and interpretation on total inter-observer variability in echocardiography: results from the quality assurance program of the STAAB cohort study.

    Science.gov (United States)

    Morbach, Caroline; Gelbrich, Götz; Breunig, Margret; Tiffe, Theresa; Wagner, Martin; Heuschmann, Peter U; Störk, Stefan

    2018-02-14

    Variability related to image acquisition and interpretation is an important issue of echocardiography in clinical trials. Nevertheless, there is no broadly accepted standard method for quality assessment of echocardiography in clinical research reports. We present analyses based on the echocardiography quality-assurance program of the ongoing STAAB cohort study (characteristics and course of heart failure stages A-B and determinants of progression). In 43 healthy individuals (mean age 50 ± 14 years; 18 females), duplicate echocardiography scans were acquired and mutually interpreted by one of three trained sonographers and an EACVI certified physician, respectively. Acquisition (AcV), interpretation (InV), and inter-observer variability (IOV; i.e., variability between the acquisition-interpretation sequences of two different observers), were determined for selected M-mode, B-mode, and Doppler parameters. We calculated Bland-Altman upper 95% limits of absolute differences, implying that 95% of measurement differences were smaller/equal to the given value: e.g. LV end-diastolic volume (mL): 25.0, 25.0, 27.9; septal e' velocity (cm/s): 3.03, 1.25, 3.58. Further, 90, 85, and 80% upper limits of absolute differences were determined for the respective parameters. Both, acquisition and interpretation, independently and sizably contributed to IOV. As such, separate assessment of AcV and InV is likely to aid in echocardiography training and quality-assurance. Our results further suggest to routinely determine IOV in clinical trials as a comprehensive measure of imaging quality. The derived 95, 90, 85, and 80% upper limits of absolute differences are suggested as reproducibility targets of future studies, thus contributing to the international efforts of standardization in quality-assurance.

  15. Changes in the relationship between annual tree growth and climatic variables for four hardwood species

    Science.gov (United States)

    E.R. Smith; J.C. Rennie

    1991-01-01

    A study was conducted to characterize temporal and spatial variability in the growth response of four major hardwood species (white oak, chestnut oak, northern red oak, and yellow-poplar) to climatic fluctuations, and to evaluate the role of environmental factors associated with difference in response among individuals. The study incorporated tree-ring data collected...

  16. Quantitative assessment of inter-observer variability in target volume delineation on stereotactic radiotherapy treatment for pituitary adenoma and meningioma near optic tract

    International Nuclear Information System (INIS)

    Yamazaki, Hideya; Ogita, Mikio; Yamashita, Koichi; Kotsuma, Tadayuki; Shiomi, Hiroya; Tsubokura, Takuji; Kodani, Naohiro; Nishimura, Takuya; Aibe, Norihiro; Udono, Hiroki; Nishikata, Manabu; Baba, Yoshimi

    2011-01-01

    To assess inter-observer variability in delineating target volume and organs at risk in benign tumor adjacent to optic tract as a quality assurance exercise. We quantitatively analyzed 21 plans made by 11 clinicians in seven CyberKnife centers. The clinicians were provided with a raw data set (pituitary adenoma and meningioma) including clinical information, and were asked to delineate the lesions and create a treatment plan. Their contouring and plans (10 adenoma and 11 meningioma plans), were then compared. In addition, we estimated the influence of differences in contouring by superimposing the respective contours onto a default plan. The median planning target volume (PTV) and the ratio of the largest to the smallest contoured volume were 9.22 cm 3 (range, 7.17 - 14.3 cm 3 ) and 1.99 for pituitary adenoma, and 6.86 cm 3 (range 6.05 - 14.6 cm 3 ) and 2.41 for meningioma. PTV volume was 10.1 ± 1.74 cm 3 for group 1 with a margin of 1 -2 mm around the CTV (n = 3) and 9.28 ± 1.8 cm 3 (p = 0.51) for group 2 with no margin (n = 7) in pituitary adenoma. In meningioma, group 1 showed larger PTV volume (10.1 ± 3.26 cm 3 ) than group 2 (6.91 ± 0.7 cm 3 , p = 0.03). All submitted plan keep the irradiated dose to optic tract within the range of 50 Gy (equivalent total doses in 2 Gy fractionation). However, contours superimposed onto the dose distribution of the default plan indicated that an excessive dose 23.64 Gy (up to 268% of the default plan) in pituitary adenoma and 24.84 Gy (131% of the default plan) in meningioma to the optic nerve in the contours from different contouring. Quality assurance revealed inter-observer variability in contour delineation and their influences on planning for pituitary adenoma and meningioma near optic tract

  17. Intra and inter ‘local climate zone’ variability of air temperature as observed by crowdsourced citizen weather stations in Berlin, Germany

    Directory of Open Access Journals (Sweden)

    Daniel Fenner

    2017-11-01

    Full Text Available A one-year data set for the year 2015 of near-surface air temperature (T$T$, crowdsourced from ‘Netatmo’ citizen weather stations (CWS in Berlin, Germany, and surroundings was analysed. The CWS data set, which has been quality-checked and filtered in a previous study, consists of T$T$ measurements from several hundred CWS. It was investigated (1 how CWS are distributed among urban and rural environments, as represented by ‘local climate zones’ (LCZ, (2 how LCZ are characterised in T$T$ along the annual cycle and concerning intra-LCZ T$T$ variability, and (3 if significant T$T$ differences between LCZ (ΔT$\\Delta T$ can be detected with CWS data. Further, it was investigated how the results from CWS compare to reference data from standard meteorological measurement stations. It can be shown that all ‘urban’ LCZ are covered by CWS, but only few CWS are located in ‘natural’ LCZ (e.g. forests or urban parks. CWS data along the annual cycle show generally good agreement to reference data, though for some LCZ monthly means between both data sets differ up to 1 K. Intra-LCZ T$T$ variability is particularly large during night-time. Statistically significant ΔT$\\Delta T$ can be detected with CWS data between various LCZ pairs, particularly for structurally dissimilar LCZ, and the results are in agreement with existing literature on LCZ or the urban heat island. Furthermore, annual mean ΔT$\\Delta T$ in CWS data agree well with reference data, thus showing the potential of CWS data for long-term studies. Several challenges related to crowdsourced CWS data need further investigation, namely missing meta data, the non-standard measurement locations, the imbalanced availability in time and space, and potentials to combine CWS and reference data to benefit from the main advantages of both, i.e., the large number of stations and the high quality of data, respectively.

  18. Long term variability of the annual hydrological regime and sensitivity to temperature phase shifts in Saxony/Germany

    Directory of Open Access Journals (Sweden)

    M. Renner

    2011-06-01

    Full Text Available Recently, climatological studies report observational evidence of changes in the timing of the seasons, such as earlier timing of the annual cycle of surface temperature, earlier snow melt and earlier onset of the phenological spring season. Also hydrological studies report earlier timing and changes in monthly streamflows. From a water resources management perspective, there is a need to quantitatively describe the variability in the timing of hydrological regimes and to understand how climatic changes control the seasonal water budget of river basins.

    Here, the timing of hydrological regimes from 1930–2009 was investigated in a network of 27 river gauges in Saxony/Germany through a timing measure derived by harmonic function approximation of annual periods of runoff ratio series. The timing measure proofed to be robust and equally applicable to both mainly pluvial river basins and snow melt dominated regimes.

    We found that the timing of runoff ratio is highly variable, but markedly coherent across the basins analysed. Differences in average timing are largely explained by basin elevation. Also the magnitude of low frequent changes in the seasonal timing of streamflow and the sensitivity to the changes in the timing of temperature increase with basin elevation. This sensitivity is in turn related to snow storage and release, whereby snow cover dynamics in late winter explain a large part of the low- and high-frequency variability.

    A trend analysis based on cumulative anomalies revealed a common structural break around the year 1988. While the timing of temperature shifted earlier by 4 days, accompanied by a temperature increase of 1 K, the timing of runoff ratio within higher basins shifted towards occurring earlier about 1 to 3 weeks. This accelerated and distinct change indicates, that impacts of climate change on the water cycle may be strongest in higher, snow melt dominated basins.

  19. Inter-rater variability in motor function assessment in Parkinson's disease between experts in movement disorders and nurses specialising in PD management.

    Science.gov (United States)

    de Deus Fonticoba, T; Santos García, D; Macías Arribí, M

    2017-05-23

    In clinical practice, assessing patients with Parkinson's disease (PD) is a complex, time-consuming task. Our purpose is to provide a rigorous and objective evaluation of how motor function in PD patients is assessed by neurologists specialising in movement disorders, on the one hand, and by nurses specialising in PD management, on the other. We conducted an observational, cross-sectional, single-centre study of 50 patients with PD (52% men; mean age: 64.7 ± 8.7 years) who were assessed between 5 January 2016 and 20 July 2016. A neurologist and a nurse evaluated motor function in the early morning hours using the Unified Parkinson's Disease Rating Scale (UPDRS) parts III and IV and Hoehn & Yahr (H&Y) scale. Tests were administered in the same PD periods (in 48 patients during the 'off' time and in 2 patients during the 'on' time). Inter-rater variability was estimated with the intraclass correlation coefficient (ICC). Forty-nine patients (98%) were classified in the same H&Y stage by both raters. Assessment times were similar for both raters. ICC for UPDRS-IV and UPDRS-III total scores were 0.955 (Pde Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Creatinine as a normalization factor to estimate the representativeness of urine sample - Intra-subject and inter-subject variability studies.

    Science.gov (United States)

    Sawant, Pramilla D; Kumar, Suja Arun; Wankhede, Sonal; Rao, D D

    2018-06-01

    In-vitro bioassay monitoring generally involves analysis of overnight urine samples (~12 h) collected from radiation workers to estimate the excretion rate of radionuclides from the body. The unknown duration of sample collection (10-16 h) adds to the overall uncertainty in computation of internal dose. In order to minimize this, IAEA recommends measurement of specific gravity or creatinine excretion rate in urine. Creatinine is excreted at a steady rate with normally functioning kidneys therefore, can be used as a normalization factor to infer the duration of collection and/or dilution of the sample, if any. The present study reports the chemical procedure standardized and its application for the estimation of creatinine as well as creatinine co-efficient in normal healthy individuals. Observations indicate higher inter-subject variability and lower constancy in daily excretion of creatinine for the same subject. Thus creatinine excretion rate may not be a useful indicator for extrapolating to 24 h sample collection. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Impact of Flavonols on Cardiometabolic Biomarkers: A Meta-Analysis of Randomized Controlled Human Trials to Explore the Role of Inter-Individual Variability

    Science.gov (United States)

    Menezes, Regina; Rodriguez-Mateos, Ana; Kaltsatou, Antonia; González-Sarrías, Antonio; Greyling, Arno; Giannaki, Christoforos; Andres-Lacueva, Cristina; Milenkovic, Dragan; Gibney, Eileen R.; Dumont, Julie; Schär, Manuel; Garcia-Aloy, Mar; Palma-Duran, Susana Alejandra; Ruskovska, Tatjana; Maksimova, Viktorija; Combet, Emilie; Pinto, Paula

    2017-01-01

    Several epidemiological studies have linked flavonols with decreased risk of cardiovascular disease (CVD). However, some heterogeneity in the individual physiological responses to the consumption of these compounds has been identified. This meta-analysis aimed to study the effect of flavonol supplementation on biomarkers of CVD risk such as, blood lipids, blood pressure and plasma glucose, as well as factors affecting their inter-individual variability. Data from 18 human randomized controlled trials were pooled and the effect was estimated using fixed or random effects meta-analysis model and reported as difference in means (DM). Variability in the response of blood lipids to supplementation with flavonols was assessed by stratifying various population subgroups: age, sex, country, and health status. Results showed significant reductions in total cholesterol (DM = −0.10 mmol/L; 95% CI: −0.20, −0.01), LDL cholesterol (DM = −0.14 mmol/L; 95% CI: −0.21, 0.07), and triacylglycerol (DM = −0.10 mmol/L; 95% CI: −0.18, 0.03), and a significant increase in HDL cholesterol (DM = 0.05 mmol/L; 95% CI: 0.02, 0.07). A significant reduction was also observed in fasting plasma glucose (DM = −0.18 mmol/L; 95% CI: −0.29, −0.08), and in blood pressure (SBP: DM = −4.84 mmHg; 95% CI: −5.64, −4.04; DBP: DM = −3.32 mmHg; 95% CI: −4.09, −2.55). Subgroup analysis showed a more pronounced effect of flavonol intake in participants from Asian countries and in participants with diagnosed disease or dyslipidemia, compared to healthy and normal baseline values. In conclusion, flavonol consumption improved biomarkers of CVD risk, however, country of origin and health status may influence the effect of flavonol intake on blood lipid levels. PMID:28208791

  2. On the distributions of annual and seasonal daily rainfall extremes in central Arizona and their spatial variability

    Science.gov (United States)

    Mascaro, Giuseppe

    2018-04-01

    This study uses daily rainfall records of a dense network of 240 gauges in central Arizona to gain insights on (i) the variability of the seasonal distributions of rainfall extremes; (ii) how the seasonal distributions affect the shape of the annual distribution; and (iii) the presence of spatial patterns and orographic control for these distributions. For this aim, recent methodological advancements in peak-over-threshold analysis and application of the Generalized Pareto Distribution (GPD) were used to assess the suitability of the GPD hypothesis and improve the estimation of its parameters, while limiting the effect of short sample sizes. The distribution of daily rainfall extremes was found to be heavy-tailed (i.e., GPD shape parameter ξ > 0) during the summer season, dominated by convective monsoonal thunderstorms. The exponential distribution (a special case of GPD with ξ = 0) was instead showed to be appropriate for modeling wintertime daily rainfall extremes, mainly caused by cold fronts transported by westerly flow. The annual distribution exhibited a mixed behavior, with lighter upper tails than those found in summer. A hybrid model mixing the two seasonal distributions was demonstrated capable of reproducing the annual distribution. Organized spatial patterns, mainly controlled by elevation, were observed for the GPD scale parameter, while ξ did not show any clear control of location or orography. The quantiles returned by the GPD were found to be very similar to those provided by the National Oceanic and Atmospheric Administration (NOAA) Atlas 14, which used the Generalized Extreme Value (GEV) distribution. Results of this work are useful to improve statistical modeling of daily rainfall extremes at high spatial resolution and provide diagnostic tools for assessing the ability of climate models to simulate extreme events.

  3. Effects of climate variables on intra-annual stem radial increment in Pinus cembra (L.) along the alpine treeline ecotone.

    Science.gov (United States)

    Gruber, Andreas; Zimmermann, Jolanda; Wieser, Gerhard; Oberhuber, Walter

    2009-08-01

    Within the alpine treeline ecotone tree growth is increasingly restricted by extreme climate conditions. Although intra-annual stem growth recorded by dendrometers can be linked to climate, stem diameter increments in slow-growing subalpine trees are masked by changes in tree water status.We tested the hypothesis that intra-annual radial stem growth in Pinus cembra is influenced by different climate variables along the treeline ecotone in the Austrian Alps. Dendrometer traces were compared with dynamics of xylem cell development to date onset of cambial activity and radial stem growth in spring.Daily fluctuations in stem radius reflected changes in tree water status throughout the treeline ecotone. Extracted daily radial increments were significantly correlated with air temperature at the timberline and treeline only, where budburst, cambial activity and enlargement of first tracheids also occurred quite similarly. A close relationship was detected between radial increment and number of enlarging tracheids throughout the treeline ecotone.We conclude that (i) the relationship between climate and radial stem growth within the treeline ecotone is dependent on a close coupling to atmospheric climate conditions and (ii) initiation of cambial activity and radial growth in spring can be distinguished from stem re-hydration by histological analysis.

  4. Identification of early target genes of aflatoxin B1 in human hepatocytes, inter-individual variability and comparison with other genotoxic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Josse, Rozenn; Dumont, Julie; Fautrel, Alain; Robin, Marie-Anne; Guillouzo, André, E-mail: andre.guillouzo@univ-rennes1.fr

    2012-01-15

    Gene expression profiling has recently emerged as a promising approach to identify early target genes and discriminate genotoxic carcinogens from non-genotoxic carcinogens and non-carcinogens. However, early gene changes induced by genotoxic compounds in human liver remain largely unknown. Primary human hepatocytes and differentiated HepaRG cells were exposed to aflatoxin B1 (AFB1) that induces DNA damage following enzyme-mediated bioactivation. Gene expression profile changes induced by a 24 h exposure of these hepatocyte models to 0.05 and 0.25 μM AFB1 were analyzed by using oligonucleotide pangenomic microarrays. The main altered signaling pathway was the p53 pathway and related functions such as cell cycle, apoptosis and DNA repair. Direct involvement of the p53 protein in response to AFB1 was verified by using siRNA directed against p53. Among the 83 well-annotated genes commonly modulated in two pools of three human hepatocyte populations and HepaRG cells, several genes were identified as altered by AFB1 for the first time. In addition, a subset of 10 AFB1-altered genes, selected upon basis of their function or tumor suppressor role, was tested in four human hepatocyte populations and in response to other chemicals. Although they exhibited large variable inter-donor fold-changes, several of these genes, particularly FHIT, BCAS3 and SMYD3, were found to be altered by various direct and other indirect genotoxic compounds and unaffected by non-genotoxic compounds. Overall, this comprehensive analysis of early gene expression changes induced by AFB1 in human hepatocytes identified a gene subset that included several genes representing potential biomarkers of genotoxic compounds. -- Highlights: ► Gene expression profile changes induced by aflatoxin B1 in human hepatocytes. ► AFB1 modulates various genes including tumor suppressor genes and proto-oncogenes. ► Important inter-individual variations in the response to AFB1. ► Some genes also altered by other

  5. Inter-reader Variability in the Use of BI-RADS Descriptors for Suspicious Findings on Diagnostic Mammography: A Multi-institution Study of 10 Academic Radiologists.

    Science.gov (United States)

    Lee, Amie Y; Wisner, Dorota J; Aminololama-Shakeri, Shadi; Arasu, Vignesh A; Feig, Stephen A; Hargreaves, Jonathan; Ojeda-Fournier, Haydee; Bassett, Lawrence W; Wells, Colin J; De Guzman, Jade; Flowers, Chris I; Campbell, Joan E; Elson, Sarah L; Retallack, Hanna; Joe, Bonnie N

    2017-01-01

    The study aimed to determine the inter-observer agreement among academic breast radiologists when using the Breast Imaging Reporting and Data System (BI-RADS) lesion descriptors for suspicious findings on diagnostic mammography. Ten experienced academic breast radiologists across five medical centers independently reviewed 250 de-identified diagnostic mammographic cases that were previously assessed as BI-RADS 4 or 5 with subsequent pathologic diagnosis by percutaneous or surgical biopsy. Each radiologist assessed the presence of the following suspicious mammographic findings: mass, asymmetry (one view), focal asymmetry (two views), architectural distortion, and calcifications. For any identified calcifications, the radiologist also described the morphology and distribution. Inter-observer agreement was determined with Fleiss kappa statistic. Agreement was also calculated by years of experience. Of the 250 lesions, 156 (62%) were benign and 94 (38%) were malignant. Agreement among the 10 readers was strongest for recognizing the presence of calcifications (k = 0.82). There was substantial agreement among the readers for the identification of a mass (k = 0.67), whereas agreement was fair for the presence of a focal asymmetry (k = 0.21) or architectural distortion (k = 0.28). Agreement for asymmetries (one view) was slight (k = 0.09). Among the categories of calcification morphology and distribution, reader agreement was moderate (k = 0.51 and k = 0.60, respectively). Readers with more experience (10 or more years in clinical practice) did not demonstrate higher levels of agreement compared to those with less experience. Strength of agreement varies widely for different types of mammographic findings, even among dedicated academic breast radiologists. More subtle findings such as asymmetries and architectural distortion demonstrated the weakest agreement. Studies that seek to evaluate the predictive value of certain mammographic features

  6. Quantifying the variability of financial disclosure information reported by authors presenting at annual spine conferences.

    Science.gov (United States)

    Ju, Brian L; Miller, Christopher P; Whang, Peter G; Grauer, Jonathan N

    2011-01-01

    In recent years, greater attention has been directed toward determining how potential financial conflicts of interest may affect the integrity of biomedical research. To address this issue, various disclosure policies have been adopted in an attempt to increase the transparency of this process. However, the consistency of such reporting among spine surgeons remains unknown. This study quantifies the variability in the self-reported disclosures of individual authors presenting at multiple spine conferences during the same year. The author disclosure information published for the 2008 North American Spine Society (NASS), Cervical Spine Research Society (CSRS), and Scoliosis Research Society (SRS), conferences were compiled into a database. We evaluated the disclosure policy for each society and compared the disclosure listings of authors who presented at more than one of these meetings. Disclosure records were available for 1,231 authors at NASS, 550 at CSRS, and 642 at SRS. Of these individuals, 278 (NASS), 129 (CSRS), and 181 (SRS) presented at one of the other conferences and 40 presented at all three conferences. North American Spine Society and CSRS required disclosure of all financial relationships, whereas SRS only requested disclosures pertinent to authors' presentations. Of the 153 authors who presented at the NASS and CSRS meetings, 51% exhibited discrepancies in their disclosure information. In contrast, only 9% of the 205 individuals whose data was listed at both the NASS and SRS conferences demonstrated irregularities. Similarly, 18% of the 56 authors who had provided information to both CSRS and SRS were inconsistent in their reporting. These findings emphasize the significant variability that currently exists in the reporting of financial conflicts of interest by authors who presented at three major spine conferences within the past year. We believe these discrepancies are likely because of confusion regarding what relationships should be acknowledged

  7. Annual variability of acetone in the UTLS region based on ICON-ART simulations

    Science.gov (United States)

    Weimer, Michael; Schröter, Jennifer; Eckstein, Johannes; Deetz, Konrad; Neumaier, Marco; Fischbeck, Garlich; Rieger, Daniel; Vogel, Heike; Vogel, Bernhard; Reddmann, Thomas; Kirner, Oliver; Ruhnke, Roland; Braesicke, Peter

    2017-04-01

    We present results of an extension to the ICOsahedral Non-hydrostatic modelling framework (ICON) [1]. ICON is a joint project of the German Weather Service and the Max-Planck-Institute for Meteorology. We use the Aerosols and Reactive Trace gases (ART) extension for ICON which currently is under development [2]. Here, the module for including emissions from external data sources has been implemented and exploited [3]. Our test cases are the emissions of volatile organic compounds (VOCs). We test the sensitivity of the VOC concentrations in the upper troposphere and lower stratosphere (UTLS) driven by prescribed emission inventories and online calculated emissions. Because VOCs are influencing the HOx equilibrium the annual cycle of VOCs matter for UTLS ozone concentrations. In the UTLS region, the HOx production due to photooxidation of the VOC acetone gets in the same order as that due to photolysis of ozone. Therefore, acetone is one of the main regulators of HOx and ozone in this region. We compare our simulations of acetone concentrations with ground-based and CARIBIC airborne measurements for different emission scenarios and different parametrisations of the acetone lifetime. [1] Zängl, G., Reinert, D., Rípodas, P., and Baldauf, M.: The ICON (ICOsahedral Non-hydrostatic) modelling framework of DWD and MPI-M: Description of the non-hydrostatic dynamical core, Quart. J. Roy. Meteor. Soc., 141, 563-579, doi:10.1002/qj.2378, 2015. [2] Rieger, D., Bangert, M., Bischoff-Gauss, I., Förstner, J., Lundgren, K., Reinert, D., Schröter, J., Vogel, H., Zängl, G., Ruhnke, R., and Vogel, B.: ICON-ART 1.0 - a new online-coupled model system from the global to regional scale, Geosci. Model Dev., 8, 1659-1676, doi:10.5194/gmd-8-1659-2015, 2015. [3] Weimer, M., Schröter, J., Eckstein, J., Deetz, K., Neumaier, M., Fischbeck, G., Rieger, D., Vogel, H., Vogel, B., Reddmann, T., Kirner, O., Ruhnke, R., and Braesicke, P.: A new module for trace gas emissions in ICON-ART 2.0: A

  8. Nitrogen deposition outweighs climatic variability in driving annual growth rate of canopy beech trees: evidence from long-term growth reconstruction across a geographic gradient.

    Science.gov (United States)

    Gentilesca, Tiziana; Rita, Angelo; Brunetti, Michele; Giammarchi, Francesco; Leonardi, Stefano; Magnani, Federico; van Noije, Twan; Tonon, Giustino; Borghetti, Marco

    2018-03-23

    In this study, we investigated the role of climatic variability and atmospheric nitrogen deposition in driving long-term tree growth in canopy beech trees along a geographic gradient in the montane belt of the Italian peninsula, from the Alps to the southern Apennines. We sampled dominant trees at different developmental stages (from young to mature tree cohorts, with tree ages spanning from 35 to 160 years) and used stem analysis to infer historic reconstruction of tree volume and dominant height. Annual growth volume (G V ) and height (G H ) variability were related to annual variability in model simulated atmospheric nitrogen deposition and site-specific climatic variables, (i.e. mean annual temperature, total annual precipitation, mean growing period temperature, total growing period precipitation, and standard precipitation evapotranspiration index) and atmospheric CO 2 concentration, including tree cambial age among growth predictors. Generalized additive models (GAM), linear mixed-effects models (LMM), and Bayesian regression models (BRM) were independently employed to assess explanatory variables. The main results from our study were as follows: i) tree age was the main explanatory variable for long-term growth variability; ii) GAM, LMM, and BRM results consistently indicated climatic variables and CO 2 effects on G V and G H were weak, therefore evidence of recent climatic variability influence on beech annual growth rates was limited in the montane belt of the Italian peninsula; iii) instead, significant positive nitrogen deposition (N dep ) effects were repeatedly observed in G V and G H ; the positive effects of N dep on canopy height growth rates, which tended to level off at N dep values greater than approximately 1.0 g m -2 y -1 were interpreted as positive impacts on forest stand above-ground net productivity at the selected study sites. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights

  9. Status inconsistency and mental health: A random effects and instrumental variables analysis using 14 annual waves of cohort data.

    Science.gov (United States)

    Milner, Allison; Aitken, Zoe; Kavanagh, Anne; LaMontagne, Anthony D; Petrie, Dennis

    2017-09-01

    Status inconsistency refers to a discrepancy between the position a person holds in one domain of their social environment comparative to their position in another domain. For example, the experience of being overeducated for a job, or not using your skills in your job. We sought to assess the relationship between status inconsistency and mental health using 14 annual waves of cohort data. We used two approaches to measuring status inconsistency: 1) being overeducated for your job (objective measure); and b) not using your skills in your job (subjective measure). We implemented a number of methodological approaches to assess the robustness of our findings, including instrumental variable, random effects, and fixed effects analysis. Mental health was assessed using the Mental Health Inventory-5. The random effects analysis indicates that only the subjective measure of status inconsistency was associated with a slight decrease in mental health (β-1.57, 95% -1.78 to -1.36, p < 0.001). This size of these coefficients was maintained in the instrumental variable analysis. We suggest that status inconsistency might explain some of the relationship between social determinants (such as work and education) and health outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Evaluating intra- and inter- sample variability in Electron Spin Resonance dating of fossil teeth: an example from Cuesta de la Bajada site (Spain).

    Science.gov (United States)

    Duval, Mathieu; Grün, Rainer; Shao, Qingfeng; Martin, Loïc; Arnold, Lee J.

    2017-04-01

    Over the last decades, technological improvements have progressively enabled to significantly decrease the amount of material required for dating analyses. In particular, the combined use of laser ablation (LA) with ICP-MS opened new possibilities for high resolution in situ U-series analyses of fossil teeth. With this technique it is now possible to directly visualise the spatial distribution of U and Th isotopes in dental tissues. Moreover, the combination of LA-ICP-MS with Electron Spin Resonance (ESR) enables an increased sampling resolution, and offers the possibility to produce several ages for different areas within a given fossil tooth. To test the potential of this new approach, several fossil teeth were collected from the Middle Palaeolithic site of Cuesta de la Bajada (Teruel, Spain). Each tooth was divided into several subsamples, providing thus several combined US-ESR age results per tooth. For each subsample, ESR, high-resolution laser ablation and solution ICP-MS U-series analyses were systematically performed. Relative beta dose rate contributions from the different tissues and the sediment were also adjusted using DosiVox software and compared with those derived from the standard approach. The results of this work give some interesting insight into the intra- and inter- sample variability that may exist at a given site. The consistency of the final US-ESR age estimates obtained on teeth are also evaluated by comparison with the (semi)-independent results derived from ESR and Luminescence dating of optically bleached quartz grains collected from the same excavation area.

  11. The Inter- and Intra-Unit Variability of a Low-Cost GPS Data Logger/Receiver to Study Human Outdoor Walking in View of Health and Clinical Studies

    Science.gov (United States)

    Abraham, Pierre; Noury-Desvaux, Bénédicte; Gernigon, Marie; Mahé, Guillaume; Sauvaget, Thomas; Leftheriotis, Georges; Le Faucheur, Alexis

    2012-01-01

    Purpose The present study evaluates the intra- and inter-unit variability of the GlobalSat® DG100 GPS data logger/receiver (DG100) when estimating outdoor walking distances and speeds. Methods Two experiments were performed using healthy subjects walking on a 400 m outdoor synthetic track. The two experiments consisted of two different outdoor prescribed walking protocols with distances ranging from 50 to 400 m. Experiment 1 examined the intra-unit variability of the DG100 (test-retest reproducibility) when estimating walking distances. Experiment 2 examined the inter-unit variability of four DG100 devices (unit to unit variability) when estimating walking distances and speeds. Results The coefficient of variation [95% confidence interval], for the reliability of estimating walking distances, was 2.8 [2.5–3.2] %. The inter-unit variability among the four DG100 units tested ranged from 2.8 [2.5–3.2] % to 3.9 [3.5–4.4] % when estimating distances and from 2.7 [2.4–3.0] % to 3.8 [3.4–4.2] % when estimating speeds. Conclusion The present study indicates that the DG100, an economical and convenient GPS data logger/receiver, can be reliably used to study human outdoor walking activities in unobstructed conditions. This device let facilitate the use of GPS in studies of health and disease. PMID:22363623

  12. Inflammatory pathway genes associated with inter-individual variability in the trajectories of morning and evening fatigue in patients receiving chemotherapy.

    Science.gov (United States)

    Wright, Fay; Hammer, Marilyn; Paul, Steven M; Aouizerat, Bradley E; Kober, Kord M; Conley, Yvette P; Cooper, Bruce A; Dunn, Laura B; Levine, Jon D; DEramo Melkus, Gail; Miaskowski, Christine

    2017-03-01

    Fatigue, a highly prevalent and distressing symptom during chemotherapy (CTX), demonstrates diurnal and interindividual variability in severity. Little is known about the associations between variations in genes involved in inflammatory processes and morning and evening fatigue severity during CTX. The purposes of this study, in a sample of oncology patients (N=543) with breast, gastrointestinal (GI), gynecological (GYN), or lung cancer who received two cycles of CTX, were to determine whether variations in genes involved in inflammatory processes were associated with inter-individual variability in initial levels as well as in the trajectories of morning and evening fatigue. Patients completed the Lee Fatigue Scale to determine morning and evening fatigue severity a total of six times over two cycles of CTX. Using a whole exome array, 309 single nucleotide polymorphisms SNPs among the 64 candidate genes that passed all quality control filters were evaluated using hierarchical linear modeling (HLM). Based on the results of the HLM analyses, the final SNPs were evaluated for their potential impact on protein function using two bioinformational tools. The following inflammatory pathways were represented: chemokines (3 genes); cytokines (12 genes); inflammasome (11 genes); Janus kinase/signal transducers and activators of transcription (JAK/STAT, 10 genes); mitogen-activated protein kinase/jun amino-terminal kinases (MAPK/JNK, 3 genes); nuclear factor-kappa beta (NFkB, 18 genes); and NFkB and MAP/JNK (7 genes). After controlling for self-reported and genomic estimates of race and ethnicity, polymorphisms in six genes from the cytokine (2 genes); inflammasome (2 genes); and NFkB (2 genes) pathways were associated with both morning and evening fatigue. Polymorphisms in six genes from the inflammasome (1 gene); JAK/STAT (1 gene); and NFkB (4 genes) pathways were associated with only morning fatigue. Polymorphisms in three genes from the inflammasome (2 genes) and the NFk

  13. The inter- and intra-event rain dropsize distribution variability of intense rain events in the Cevennes-Vivarais region, France.

    Science.gov (United States)

    Yu, N.; Hazenberg, P.; Boudevillain, B.; Delrieu, G.; Uijlenhoet, R.

    2009-04-01

    The Cévennes-Vivarais region situated in the southern part of France is prone to heavy and long lasting rainfall events which occasionally lead to severe flashfloods. In order to gain an improved understanding of these severe rainfall events the Cévennes-Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) has set up a rainfall observation system consisting of a network of three operational weather radars, a dense network of raingauges and a disdrometer situated at a distance of about 57 km from the nearest radar [Delrieu et al., 2005]. The current study extends the DSD analysis results obtained by Chapon et al. (2008) with almost 2.5 years of disdrometer data. For a series of intense rainfall events, Chapon et al. (2008) show that the intra-event characteristics of precipitation has a dominant effect on the Z-R parameterization compared to inter-event variability. The study presented here applies the general scaling for raindrop size distributions as developed by Sempere Torres et al. (1994) which states that the different integral rainfall variables are related by power functions. For heavy rainfall, drop growth and breakup are balanced and a so called equilibrium condition occurs. As a result, characteristic raindrop sizes are constant and the different moments are proportional. Uijlenhoet et al. [2003] found this type of equilibrium conditions for rainfall intensities > 100 mm/h. In case of the Cévennes-Vivarais, analyzing the overall dataset shows that such equilibrium conditions already start to occur for intensities > 50 mm/h. It is relevant for the development of radar rainfall retrieval algorithms to find out how the different DSD properties (such as rain rate and radar reflectivity) are related to each other in such heavy rainfall events and how they change at different temporal aggregation scales and threshold values. The next step considers the volume-scanning radar data and DSD measurements for a selected set of heavy rain events, in

  14. SU-E-J-275: Impact of the Intra and Inter Observer Variability in the Delineation of Parotid Glands On the Dose Calculation During Head and Neck Helical Tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jodda, A; Piotrowski, T [Greater Poland Cancer Centre Poznan (Poland)

    2014-06-01

    Purpose: The intra- and inter-observer variability in delineation of the parotids on the kilo-voltage computed tomography (kVCT) and mega-voltage computed tomography (MVCT) were examined to establish their impact on the dose calculation during adaptive head and neck helical tomotherapy (HT). Methods: Three observers delineated left and right parotids for ten randomly selected patients with oropharynx cancer treated on HT. The pre-treatment kVCT and the MVCT from the first fraction of irradiation were selected to delineation. The delineation procedure was repeated three times by each observer. The parotids were delineated according to the institutional protocol. The analyses included intra-observer reproducibility and inter-structure, -observer and -modality variability of the volume and dose. Results: The differences between the left and right parotid outlines were not statistically significant (p>0.3). The reproducibility of the delineation was confirmed for each observer on the kVCT (p>0.2) and on the MVCT (p>0.1). The inter-observer variability of the outlines was significant (p<0.001) as well as the inter-modality variability (p<0.006). The parotids delineated on the MVCT were 10% smaller than on the kVCT. The inter-observer variability of the parotids delineation did not affect the average dose (p=0.096 on the kVCT and p=0.176 on the MVCT). The dose calculated on the MVCT was higher by 3.3% than dose from the kVCT (p=0.009). Conclusion: Usage of the institutional protocols for the parotids delineation reduces intra-observer variability and increases reproducibility of the outlines. These protocols do not eliminate delineation differences between the observers, but these differences are not clinically significant and do not affect average doses in the parotids. The volumes of the parotids delineated on the MVCT are smaller than on the kVCT, which affects the differences in the calculated doses.

  15. Inter-observer variability of visual analysis of "stress"-only adenosine first-pass myocardial perfusion imaging in relation to clinical experience and reading criteria

    NARCIS (Netherlands)

    Lubbers, D. D.; Kuijpers, D.; Bodewes, R.; Kappert, P.; Kerkhof, M.; van Ooijen, P. M. A.; Oudkerk, M.

    To assess the inter-observer agreement of adenosine "stress"-only visual analysis of perfusion MR images in relation to experience and reading criteria. 106 adenosine perfusion MR examinations out of 350, 46 consecutive positive examinations and 60 randomly selected negative examinations were

  16. Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain)

    International Nuclear Information System (INIS)

    Peña-Fernández, A.; Lobo-Bedmar, M.C.; González-Muñoz, M.J.

    2015-01-01

    Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. - Highlights: • Anthropogenic activities may affect the seasonal metal variation in Alcalá's soils. • Weather characteristics may also influence the seasonal metal variation in soils. • Alcalá's continual urban growth may have increased the levels of metals in its soils. • Metal variability in Alcalá's industrial soils might be dependent on their sources. • High soil metal content might make it difficult to identify temporal variation

  17. Annual baseflow variations as influenced by climate variability and agricultural land use change in the Missouri River Basin

    Science.gov (United States)

    Ahiablame, Laurent; Sheshukov, Aleksey Y.; Rahmani, Vahid; Moriasi, Daniel

    2017-08-01

    The Missouri River system has a large water storage capacity, where baseflow plays an important role. Understanding historical baseflow characteristics with respect to climate and land use impacts is essential for effective planning and management of water resources in the Missouri River Basin (MORB). This study evaluated statistical trends in baseflow and precipitation for 99 MORB minimally disturbed watersheds during 1950-2014. Elasticity of baseflow to climate variability and agricultural land use change were quantified for the 99 studied watersheds. Baseflow was derived from daily streamflow records with a recursive digital filter method. The results showed that baseflow varied between 38 and 80% (0 and 331 mm/year) of total streamflow with an average of 60%, indicating that more than half of streamflow in the MORB is derived from baseflow. The trend analysis revealed that precipitation increased during the study period in 78 out of 99 watersheds, leading to 1-3.9% noticeable increase in baseflow for 68 of 99 watersheds. Although the changes in baseflow obtained in this study were a result of the combined effects of climate and land use change across the basin, upward trends in baseflow generally coincide with increased precipitation and agricultural land use trends in the basin. Agricultural land use increase mostly led to a 0-5.7% decrease in annual baseflow in the basin, except toward east of the basin where baseflow mostly increased with agricultural land use increase (0.1-2.0%). In general, a 1% increase in precipitation and a 1% increase in agricultural land use resulted in 1.5% increase and 0.2% decrease in baseflow, respectively, during the study period. These results are entirely dependent on the quality of data used; however, they provide useful insight into the relative influence of climate and land use change on baseflow conditions in the Great Plains region of the USA.

  18. Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Peña-Fernández, A. [Departamento de Ciencias Biomédicas, Unidad de Toxicología, Universidad de Alcalá, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcalá de Henares, Madrid (Spain); Lobo-Bedmar, M.C. [Instituto Madrileño de Investigación y Desarrollo Rural Agrario y Alimentario (IMIDRA), Finca el Encín, Crta. Madrid-Barcelona Km, 38.2, 28800 Alcalá de Henares, Madrid (Spain); González-Muñoz, M.J., E-mail: mariajose.gonzalez@uah.es [Departamento de Ciencias Biomédicas, Unidad de Toxicología, Universidad de Alcalá, Crta. Madrid-Barcelona Km, 33.6, 28871 Alcalá de Henares, Madrid (Spain)

    2015-01-15

    Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. - Highlights: • Anthropogenic activities may affect the seasonal metal variation in Alcalá's soils. • Weather characteristics may also influence the seasonal metal variation in soils. • Alcalá's continual urban growth may have increased the levels of metals in its soils. • Metal variability in Alcalá's industrial soils might be dependent on their sources. • High soil metal content might make it difficult to identify temporal variation.

  19. Inter- and Intra-Observer Variability of the Volume of Cervical Ossification of the Posterior Longitudinal Ligament Using Medical Image Processing Software.

    Science.gov (United States)

    Shin, Dong Ah; Ji, Gyu Yeul; Oh, Chang Hyun; Kim, Keung Nyun; Yoon, Do Heum; Shin, Hyunchul

    2017-07-01

    Computed tomography (CT)-based method of three dimensional (3D) analysis (MIMICS ® , Materialise, Leuven, Belgium) is reported as very useful software for evaluation of OPLL, but its reliability and reproducibility are obscure. This study was conducted to evaluate the accuracy of MIMICS ® system, and inter- and intra-observer reliability in the measurement of OPLL. Three neurosurgeons independently analyzed the randomly selected 10 OPLL cases with medical image processing software (MIMICS ® ) which create 3D model with Digital Imaging and Communication in Medicine (DICOM) data from CT images after brief explanation was given to examiners before the image construction steps. To assess the reliability of inter- and intra-examiner intraclass correlation coefficient (ICC), 3 examiners measured 4 parameters (volume, length, width, and length) in 10 cases 2 times with 1-week interval. The inter-examiner ICCs among 3 examiners were 0.996 (95% confidence interval [CI], 0.987-0.999) for volume measurement, 0.973 (95% CI, 0.907-0.978) for thickness, 0.969 (95% CI, 0.895-0.993) for width, and 0.995 (95% CI, 0.983-0.999) for length. The intra-examiner ICCs were 0.994 (range, 0.991-0.996) for volume, 0.996 (range, 0.944-0.998) for length, 0.930 (range, 0.873-0.947) for width, and 0.987 (range, 0.985-0.995) for length. The medical image processing software (MIMICS ® ) provided detailed quantification OPLL volume with minimal error of inter- and intra-observer reliability in the measurement of OPLL.

  20. Inter Annual Variability of the Acoustic Propagation in the Yellow Sea Identified from a Synoptic Monthly Gridded Database as Compared with GDEM

    Science.gov (United States)

    2016-09-01

    tested on data using the Parallel Ocean Program (POP) model (Smith 2002). SMG-WOD maintains spatial resolution for temperature and salinity as found...computing. MATLAB codes designed to work with other conventional computer programs such as C++, Java , FORTRAN, and Python allowing the user to integrate...experience, and I will never forget the time she dedicated toward my success. Finally, I want to thank my program officer, CDR Paula Travis, for her role as

  1. Inter-Annual Variability of the Acoustic Propagation in the Mediterranean Sea Identified from a Synoptic Monthly Gridded Database as Compared with GDEM

    Science.gov (United States)

    2016-12-01

    the Nile River . The Diversion of Nile River ... The Mediterranean Sea is an important area to research for the navy’s tactical issues, especially given its historical importance and its position...600 m deep), and consists of important regional seas: the Ionian, Levantine, Adriatic, and Aegean Seas. The maximum depths are approximately

  2. Seasonal and inter-annual variability of remotely-sensed sea surface height, visible light and chlorophyll in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Gawad, M.M.; Pokle, A.S.

    to the global warming, as increased warming will lead to increased sea level rise due to melting of polar ice-caps. The chlorophyll pigment concentration indicates the biological productivity of the region and hence is important to understand its changes...

  3. Seasonal and inter-annual variability of soil CO2 efflux in a Norway spruce forest over an eight-year study

    Czech Academy of Sciences Publication Activity Database

    Acosta, Manuel; Dařenová, Eva; Krupková, Lenka; Pavelka, Marian

    256-257 (2018), s. 93-103 ISSN 0168-1923 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) EF16_013/0001609 Institutional support: RVO:86652079 Keywords : Automated chamber system * Day of the year * Picea abies * Soil carbon flux * Temperature Soil water content Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.887, year: 2016

  4. Stereological estimation of nuclear volume in benign and malignant melanocytic lesions of the skin. Inter- and intraobserver variability of malignancy grading

    DEFF Research Database (Denmark)

    Sørensen, Flemming Brandt; Ottosen, P D

    1991-01-01

    The volume-weighted, mean nuclear volume (nuclear vv) may be estimated without any assumptions regarding nuclear shape using modern stereological techniques. As a part of an investigation concerning the prospects of nuclear vv for classification and malignancy grading of cutaneous melanocytic...... and robust, with more than 85% of the associated observed variance explained by differences among different tumors. Inter- and intraobserver reproducibilities are high, showing correlation coefficients of .86 and .96, respectively, with slopes of the regression lines close to unity. It is concluded...

  5. Semi-Automatic Evaluation of Intrasubject Variability and Inter-session of Cerebral Activation Areas by Neuro functional Magnetic Resonance (FMRI)

    International Nuclear Information System (INIS)

    Rascovsky, Simon; Delgado, Jorge Andres; Sanz, Alexander

    2008-01-01

    To verify the reproducibility of word generation, text comprehension, antonyms generation and motor/somatosensory RMF protocols in a test-retest evaluation through a semiautomatic stereotaxical localization method for activation comparison. Methods: Word generation, text comprehension, antonyms generation and motor/somatosensory FMRI paradigms were applied on 8 healthy subjects on two separate sessions, performing the evaluation of inter-session activations through conjunction and cluster analysis. Results: Activations according to Brodmann areas were reproducible in 50%, 62.5% and 75% for word generation, text comprehension and antonyms generation respectively. For the motor paradigms, right motor conjoined activations were found in 86% of subjects and in 100% of subjects for left conjoined activations. Conclusions: The semi-automatic method of determining inter-session areas of common activation allows its use for functional cytoarchitectonic localization of fMRI activations with minimal intervention, and can be used as a quality control measure of the different paradigms used in RMF, minimizing observer bias.

  6. Annual ecosystem respiration variability of alpine peatland on the eastern Qinghai-Tibet Plateau and its controlling factors.

    Science.gov (United States)

    Peng, Haijun; Hong, Bing; Hong, Yetang; Zhu, Yongxuan; Cai, Chen; Yuan, Lingui; Wang, Yu

    2015-09-01

    Peatlands are widely developed in the eastern Qinghai-Tibet Plateau, but little is known about carbon budgets for these alpine peatland ecosystems. In this study, we used an automatic chamber system to measure ecosystem respiration in the Hongyuan peatland, which is located in the eastern Qinghai-Tibet Plateau. Annual ecosystem respiration measurements showed a typical seasonal pattern, with the peak appearing in June. The highest respiration was 10.43 μmol CO2/m(2)/s, and the lowest was 0.20 μmol CO2/m(2)/s. The annual average ecosystem respiration was 2.06 μmol CO2/m(2)/s. The total annual respiration was 599.98 g C/m(2), and respiration during the growing season (from May to September) accounted for 78 % of the annual sum. Nonlinear regression revealed that ecosystem respiration has a significant exponential correlation with soil temperature at 10-cm depth (R (2) = 0.98). The Q 10 value was 3.90, which is far higher than the average Q 10 value of terrestrial ecosystems. Ecosystem respiration had an apparent diurnal variation pattern in growing season, with peaks and valleys appearing at approximately 14:00 and 10:00, respectively, which could be explained by soil temperature and soil water content variation at 10-cm depth.

  7. Effect of variable annual precipitation and nutrient input on nitrogen and phosphorus transport from two Midwestern agricultural watersheds

    Science.gov (United States)

    Kalkhoff, Stephen J.; Hubbard, Laura E.; Tomer, Mark D.; James, D.E.

    2016-01-01

    Precipitation patterns and nutrient inputs affect transport of nitrate (NO3-N) and phosphorus (TP) from Midwest watersheds. Nutrient concentrations and yields from two subsurface-drained watersheds, the Little Cobb River (LCR) in southern Minnesota and the South Fork Iowa River (SFIR) in northern Iowa, were evaluated during 1996–2007 to document relative differences in timings and amounts of nutrients transported. Both watersheds are located in the prairie pothole region, but the SFIR exhibits a longer growing season and more livestock production. The SFIR yielded significantly more NO3-N than the LCR watershed (31.2 versus 21.3 kg NO3-N ha− 1 y− 1). The SFIR watershed also yielded more TP than the LCR watershed (1.13 versus 0.51 kg TP ha− 1 yr− 1), despite greater TP concentrations in the LCR. About 65% of NO3-N and 50% of TP loads were transported during April–June, and < 20% of the annual loads were transported later in the growing season from July–September. Monthly NO3-N and TP loads peaked in April from the LCR but peaked in June from the SFIR; this difference was attributed to greater snowmelt runoff in the LCR. The annual NO3-N yield increased with increasing annual runoff at a similar rate in both watersheds, but the LCR watershed yielded less annual NO3-N than the SFIR for a similar annual runoff. These two watersheds are within 150 km of one another and have similar dominant agricultural systems, but differences in climate and cropping inputs affected amounts and timing of nutrient transport.

  8. Trait-Based Community Assembly along an Elevational Gradient in Subalpine Forests: Quantifying the Roles of Environmental Factors in Inter- and Intraspecific Variability.

    Directory of Open Access Journals (Sweden)

    Ya-Huang Luo

    Full Text Available Understanding how communities respond to environmental variation is a central goal in ecology. Plant communities respond to environmental gradients via intraspecific and/or interspecific variation in plant functional traits. However, the relative contribution of these two responses to environmental factors remains poorly tested. We measured six functional traits (height, leaf thickness, specific leaf area (SLA, leaf carbon concentration (LCC, leaf nitrogen concentration (LNC and leaf phosphorus concentration (LPC for 55 tree species occurring at five elevations across a 1200 m elevational gradient of subalpine forests in Yulong Mountain, Southwest China. We examined the relative contribution of interspecific and intraspecific traits variability based on community weighted mean trait values and functional diversity, and tested how different components of trait variation respond to different environmental axes (climate and soil variables. Species turnover explained the largest amount of variation in leaf morphological traits (leaf thickness and SLA across the elevational gradient. However, intraspecific variability explained a large amount of variation (49.3%-76.3% in three other traits (height, LNC and LPC despite high levels of species turnover. The detection of limiting similarity in community assembly was improved when accounting for both intraspecific and interspecific variability. Different components of trait variation respond to different environmental axes, especially soil water content and climatic variables. Our results indicate that intraspecific variation is critical for understanding community assembly and evaluating community response to environmental change.

  9. Trait-Based Community Assembly along an Elevational Gradient in Subalpine Forests: Quantifying the Roles of Environmental Factors in Inter- and Intraspecific Variability.

    Science.gov (United States)

    Luo, Ya-Huang; Liu, Jie; Tan, Shao-Lin; Cadotte, Marc William; Wang, Yue-Hua; Xu, Kun; Li, De-Zhu; Gao, Lian-Ming

    2016-01-01

    Understanding how communities respond to environmental variation is a central goal in ecology. Plant communities respond to environmental gradients via intraspecific and/or interspecific variation in plant functional traits. However, the relative contribution of these two responses to environmental factors remains poorly tested. We measured six functional traits (height, leaf thickness, specific leaf area (SLA), leaf carbon concentration (LCC), leaf nitrogen concentration (LNC) and leaf phosphorus concentration (LPC)) for 55 tree species occurring at five elevations across a 1200 m elevational gradient of subalpine forests in Yulong Mountain, Southwest China. We examined the relative contribution of interspecific and intraspecific traits variability based on community weighted mean trait values and functional diversity, and tested how different components of trait variation respond to different environmental axes (climate and soil variables). Species turnover explained the largest amount of variation in leaf morphological traits (leaf thickness and SLA) across the elevational gradient. However, intraspecific variability explained a large amount of variation (49.3%-76.3%) in three other traits (height, LNC and LPC) despite high levels of species turnover. The detection of limiting similarity in community assembly was improved when accounting for both intraspecific and interspecific variability. Different components of trait variation respond to different environmental axes, especially soil water content and climatic variables. Our results indicate that intraspecific variation is critical for understanding community assembly and evaluating community response to environmental change.

  10. Assessing variability in chemical acute toxicity of unionid mussels: Influence of intra- and inter-laboratory testing, life stage, and species

    Science.gov (United States)

    The authors developed a toxicity database for unionid mussels to examine the extent of intra- and interlaboratory variability in acute toxicity tests with mussel larvae (glochidia) and juveniles; the extent of differential sensitivity of the 2 life stages; and the variation in se...

  11. Medizinbibliotheken: inter:disziplinär – inter:national –inter:aktiv

    Directory of Open Access Journals (Sweden)

    Bauer, Bruno

    2017-12-01

    Full Text Available The focus of the current issue 3/2017 of GMS Medizin – Bibliothek – Information is the annual conference 2017 of the German Medical Libraries Association in Vienna. The motto of the conference was “Medical Libraries: inter:disciplinary – inter:national – inter:active”. The authors in this issue are Bruno Bauer (Austrian Transition to Open Access 2017–2020, Beata Górczynska (Development and structure of Polish veterinary school system and its libraries, Katharina Heldt, Henriette Senst & Jessica Riedel (Salon on the institute’s history: outstanding artifacts. 28.01.2016 to 15.12.2016, Jutta Matrisciano, Martina Semmler-Schmetz & Saskia Rohmer (Advice – From info snack to special menu: Solutions of the MedMA-Bib, Stefan Nortmann (The ‘Ersti-Café’ of the Medical Branch Library Münster, Sandra Rümmele (Toolbox: The new teaching library project of the Central Medical Library of the University Medical Center Hamburg-Eppendorf, Eva Seidlmayer & Christoph Poley (One Health – Transdisciplinarity at ZB MED and Heike Andermann (“Medical Libraries: inter:disciplinary – inter:national – inter:active”. Annual Meeting of the German Medical Library Association (AGMB, September 25 to 27, 2017 in Vienna. Furthermore this focus issue features articles from Stefan Grün & Christoph Poley (Statistical evaluation of semantic entities from metadata and full text on German Medical Science corpora and Iris Reimann (German MLA News; Competition of the German MLA Pioneer projects in medical libraries 2017: Introduction of the winners; Competition of the German MLA (AGMB Pioneer projects in medical libraries 2018 – Announcement.

  12. Hepatic transcriptome analysis of inter-family variability in flesh n-3 long-chain polyunsaturated fatty acid content in Atlantic salmon

    Directory of Open Access Journals (Sweden)

    Morais Sofia

    2012-08-01

    Full Text Available Abstract Background Genetic selection of Atlantic salmon families better adapted to alternative feed formulations containing high levels of vegetable ingredients has been suggested to ensure sustainable growth of aquaculture. The present study aimed to identify molecular pathways that could underlie phenotypic differences in flesh n-3 long-chain polyunsaturated fatty acid (LC-PUFA levels when fish are fed vegetable oil diets. Liver transcriptome was analyzed and compared in four families presenting higher or lower n-3 LC-PUFA contents at two contrasting flesh total lipid levels. Results The main effect of n-3 LC-PUFA contents was in the expression of immune response genes (38% of all significantly affected genes, broadly implicated in the modulation of inflammatory processes and innate immune response. Although genetic evaluations of traits used in the breeding program revealed that the chosen families were not balanced for viral disease resistance, this did not fully explain the preponderance of immune response genes in the transcriptomic analysis. Employing stringent statistical analysis no lipid metabolism genes were detected as being significantly altered in liver when comparing families with high and low n-3 LC-PUFA flesh contents. However, relaxing the statistical analysis enabled identification of potentially relevant effects, further studied by RT-qPCR, in cholesterol biosynthesis, lipoprotein metabolism and lipid transport, as well as eicosanoid metabolism particularly affecting the lipoxygenase pathway. Total lipid level in flesh also showed an important effect on immune response and 8% of significantly affected genes related to lipid metabolism, including a fatty acyl elongase (elovl2, an acyl carrier protein and stearoyl-CoA desaturase. Conclusions Inter-family differences in n-3 LC-PUFA content could not be related to effects on lipid metabolism, including transcriptional modulation of the LC-PUFA biosynthesis pathway. An

  13. Inter- and intra-specimen variability masks reliable temperature control on shell Mg/Ca ratios in laboratory- and field-cultured Mytilus edulis and Pecten maximus (bivalvia

    Directory of Open Access Journals (Sweden)

    H. A. Kennedy

    2008-09-01

    Full Text Available The Mg/Ca ratios of biogenic calcite is commonly seen as a valuable palaeo-proxy for reconstructing past ocean temperatures. The temperature dependence of Mg/Ca ratios in bivalve calcite has been the subject of contradictory observations. The palaeoceanographic use of a geochemical proxy is dependent on initial, rigorous calibration and validation of relationships between the proxy and the ambient environmental variable to be reconstructed. Shell Mg/Ca ratio data are reported for the calcite of two bivalve species, Mytilus edulis (common mussel and Pecten maximus (king scallop, which were grown in laboratory culturing experiments at controlled and constant aquarium seawater temperatures over a range from ~10 to ~20°C. Furthermore, Mg/Ca ratio data of laboratory- and field-grown M. edulis specimens were compared. Only a weak, albeit significant, shell Mg/Ca ratio–temperature relationship was observed in the two bivalve species: M. edulis (r2=0.37, p0.001 for laboratory-cultured specimens and r2=0.50, p0.001 for field-cultured specimens and P. maximus (r2=0.21, p0.001 for laboratory-cultured specimens only. In the two species, shell Mg/Ca ratios were not found to be controlled by shell growth rate or salinity. The Mg/Ca ratios in the shells exhibited a large degree of variability among and within species and individuals. The results suggest that the use of bivalve calcite Mg/Ca ratios as a temperature proxy is limited, at least in the species studied to date. Such limitations are most likely due to the presence of physiological effects on Mg incorporation in bivalve calcite. The utilization is further limited by the great variability both within and among shells of the same species that were precipitated under the same ambient conditions.

  14. Annual dynamics of daylight variability and contrast a simulation-based approach to quantifying visual effects in architecture

    CERN Document Server

    Rockcastle, Siobhan

    2013-01-01

    Daylight is a dynamic source of illumination in architectural space, creating diverse and ephemeral configurations of light and shadow within the built environment. Perceptual qualities of daylight, such as contrast and temporal variability, are essential to our understanding of both material and visual effects in architecture. Although spatial contrast and light variability are fundamental to the visual experience of architecture, architects still rely primarily on intuition to evaluate their designs because there are few metrics that address these factors. Through an analysis of contemporary

  15. Unit-specific calibration of Actigraph accelerometers in a mechanical setup - is it worth the effort? The effect on random output variation caused by technical inter-instrument variability in the laboratory and in the field

    DEFF Research Database (Denmark)

    Moeller, Niels C; Korsholm, Lars; Kristensen, Peter L

    2008-01-01

    *min-1 vs. calibrated SDbetween units = 67 counts*min-1). However, the effect of applying the derived calibration to children's and adolescents' free living physical activity data did not alter the coefficient of variation (CV) (children: CVraw = 30.2% vs. CVcalibrated = 30.4%, adolescents: CVraw = 36...... accelerometers in a mechanical setup using four different settings varying in frequencies and/or amplitudes. Calibration effect was analysed by comparing raw and calibrated data after applying unit-specific calibration factors to data obtained during quality checks in a mechanical setup and to data collected...... conditions had no apparent effect on inter-instrument variability. In all probability, the effect of technical calibration was primarily attenuated in the field by other more dominant sources of variation. However, routine technical assessments are still very important for determining the acceleration...

  16. Work flow with manual re-registration of cardiac 18F-FDG PET and attenuation correction CT to compensate for respiratory motion: Effects and inter-operator variability

    DEFF Research Database (Denmark)

    Juhl, Christian; Christensen, Nana Louise; Møller, Lone W.

    , attenuation artefacts are often observed on the lateral wall of the left ventricle. Many strategies has been proposed to reduce these artefacts, including averaging multiple CTs, respiratory gating and manual re-registration1-3. However, for scanner platform-independent implementation, manual re......-registration is currently the most feasible. In this study, we examine both the effect on misalignment artefacts and the inter-operator variability of manual re-registration performed by the technologist in a step before the final image reconstruction and verified by a second technologist before image analysis. Method: 40...... 18F-FDG viability scans were examined. After the patient scan, a fast image reconstruction of low quality was made and used for manual re-registration of PET and AC CT, before starting the high quality reconstruction used for analysis. The left ventricle was reoriented and segmented in QPS (Cedar...

  17. Work flow with manual re-registration of cardiac 18F-FDG PET and attenuation correction CT to compensate for respiratory motion: Effects and inter-operator variability

    DEFF Research Database (Denmark)

    Juhl, Christian; Christensen, Nana Louise; Møller, Lone W.

    Aim: Cardiac PET exams with CT for attenuation correction are increasing in number. However, due to different natures of the PET (average over many respiratory cycles) and the CT exam (snap-shot during one respiratory cycle) and the large difference in density of the cardiac and lung tissue......-registration is currently the most feasible. In this study, we examine both the effect on misalignment artefacts and the inter-operator variability of manual re-registration performed by the technologist in a step before the final image reconstruction and verified by a second technologist before image analysis. Method: 40...... 18F-FDG viability scans were examined. After the patient scan, a fast image reconstruction of low quality was made and used for manual re-registration of PET and AC CT, before starting the high quality reconstruction used for analysis. The left ventricle was reoriented and segmented in QPS (Cedar...

  18. Regional climate pattern during two millennia estimated from annual tree rings of Yaku cedar trees: a hint for solar variability?

    Science.gov (United States)

    Muraki, Yasushi; Mitsutani, Takumi; Shibata, Shoichi; Kuramata, Syuichi; Masuda, Kimiaki; Nagaya, Kentaro

    2015-02-01

    We analyzed trees that have survived on Yaku island (Yakushima) for 2,000 years. Quite surprisingly, the Fourier and wavelet analyses of the annual growth rate identified 2 cycles of periodicities of 11 and (24 ± 4) years during the Oort, Wolf, Spörer, Maunder, and Dalton minima. The 11-year periodicity originated from solar activity, while the (24 ± 4)-year periodicity may be related to the Pacific Decadal Oscillation (PDO). In particular, we have discovered an 11-year periodicity in the meteorological daylight-hour data from Yakushima in the month of June during 1938 to 2013 and a 24-year periodicity in July. The growth rate of the tree rings may be affected by the variation of the daylight hour.

  19. Stochastic models and spectra of interannual variability of mean annual sea surface temperature in the North Atlantic

    Science.gov (United States)

    Privalsky, V. E.

    1988-10-01

    Estimates of one- and two-variate autoregressive models of mean annual sea surface temperature (SST) in five Smed squares in the North Atlantic are obtained by analysing time series of SST, 1881-1970. Year-to-year variations of SST are shown to follow the AR model of order one with a regression parameter of 0.5 so that their generalized spectrum decreases monotonically and relatively fast with frequency while the limits of statistical predictability amount up to two years. Two-variate models of SST reveal frequency-dependent time lags up to three years and possess slightly better statistical predictability. A feedback in the system of warm and cold currents is found with a characteristic time scale of about six years, which plays an important role in the system's energy budget.

  20. Importance and inter-relationship of tissue Doppler variables for predicting adverse outcomes in high-risk patients: an analysis of 388 diabetic patients referred for coronary angiography

    DEFF Research Database (Denmark)

    Andersson, Charlotte; Gislason, Gunnar H; Møgelvang, Rasmus

    2012-01-01

    AIMS: To investigate the relative importance of individual tissue Doppler imaging variables to predict adverse events in a high-risk population with diabetes, ischaemic heart disease, and/or systolic dysfunction. METHODS AND RESULTS: Transthoracic echocardiograms were analysed in 388 diabetic...... patients without significant valve disease, bundle branch block, and atrial fibrillation who underwent coronary angiography. Multivariable Cox's regression analyses were used to establish the association between peak systolic (s'), early diastolic (e'), and late diastolic (a') tissue velocities...... and outcomes (hospitalization for heart failure or death). The mean age and left ventricular ejection fraction (LVEF) was 66 ± 10 years and 45 ± 12%, respectively. During 2.3 (±1.0) years of follow-up, 91 patients (24%) met the combined endpoint. After adjustment for LVEF, coronary artery pathology, heart...

  1. Inter-daily variability of a strong thermally-driven wind system over the Atacama Desert of South America: synoptic forcing and short-term predictability using the GFS global model

    Science.gov (United States)

    Jacques-Coper, Martín; Falvey, Mark; Muñoz, Ricardo C.

    2015-07-01

    Crucial aspects of a strong thermally-driven wind system in the Atacama Desert in northern Chile during the extended austral winter season (May-September) are studied using 2 years of measurement data from the Sierra Gorda 80-m meteorological mast (SGO, 22° 56' 24″ S; 69° 7' 58″ W, 2,069 m above sea level (a.s.l.)). Daily cycles of atmospheric variables reveal a diurnal (nocturnal) regime, with northwesterly (easterly) flow and maximum mean wind speed of 8 m/s (13 m/s) on average. These distinct regimes are caused by pronounced topographic conditions and the diurnal cycle of the local radiative balance. Wind speed extreme events of each regime are negatively correlated at the inter-daily time scale: High diurnal wind speed values are usually observed together with low nocturnal wind speed values and vice versa. The associated synoptic conditions indicate that upper-level troughs at the coastline of southwestern South America reinforce the diurnal northwesterly wind, whereas mean undisturbed upper-level conditions favor the development of the nocturnal easterly flow. We analyze the skill of the numerical weather model Global Forecast System (GFS) in predicting wind speed at SGO. Although forecasted wind speeds at 800 hPa do show the diurnal and nocturnal phases, observations at 80 m are strongly underestimated by the model. This causes a pronounced daily cycle of root-mean-squared error (RMSE) and bias in the forecasts. After applying a simple Model Output Statistics (MOS) post-processing, we achieve a good representation of the wind speed intra-daily and inter-daily variability, a first step toward reducing the uncertainties related to potential wind energy projects in the region.

  2. Modeling the Spatial and Temporal Variability of Precipitation in Northwest Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Arab Amiri

    2017-12-01

    Full Text Available Spatial and temporal variability analysis of precipitation is an important task in water resources planning and management. This study aims to analyze the spatial and temporal variability of precipitation in the northeastern corner of Iran using data from 24 well-distributed weather stations between 1991 and 2015. The mean annual rainfall, precipitation concentration index (PCI, and their coefficients of variation were mapped to examine the spatial variability of rainfall. An artificial neural network (ANN in association with the inverse distance weighted (IDW method was proposed as a hybrid interpolation method to map the spatial distribution of the detected trends of mean annual rainfall and PCI over the study region. In addition, principal component analysis (PCA was applied to annual precipitation time series in order to verify the results of the analysis using the mean annual rainfall and PCI data sets. Results show high variation in inter-annual precipitation in the west, and a moderate to high intra-annual variability over the whole region. Irregular year-to-year precipitation concentration is also observed in the northeastern and northwestern parts. All in all, the highest variations in inter-annual and intra-annual precipitation occurred over the western and northern parts, while the lowest variability was observed in the eastern part (i.e., the coastal region.

  3. Semi-automated renal region of interest selection method using the double-threshold technique: inter-operator variability in quantitating 99mTc-MAG3 renal uptake

    International Nuclear Information System (INIS)

    Tomaru, Yumi; Inoue, Tomio; Oriuchi, Noboru; Endo, Keigo; Takahashi, Kazukuni

    1998-01-01

    In calculating the relative and absolute renal uptake of technetium-99m mercaptoacetyltriglycine (MAG3), inter-operator variability in the assignment of the renal region of interest (ROI) is a critical factor. Our goal was to develop a semi-automated method of assigning the renal ROI and then to compare the inter-operator variability in calculating the percent injected dose (%ID) in the kidney at 1-2 min, using semi-automated versus manual ROIs. The manual ROIs were drawn independently by three operators (A, B and C). Operator A had about 20 years, experience in nuclear medicine, while operators B and C respectively had 3 years and 1 year of experience. In the semi-automated renal ROI selection method using the double-threshold technique, the operators only click around the centre of each kidney. The same three operators processed the ROIs using this double-threshold method on 1-2 min images. The semi-automated method failed in three kidneys with very markedly reduced function owing to superimposition by liver or spleen. Inter-operator reproducibility in the remaining 59 kidneys was estimated using manual and semi-automated ROIs. With manual ROIs, the %ID (mean±standard error of mean) was 4.32±0.167 for A, 4.14±0.165 for B and 3.28±0.139 for C. Although there was good correlation among them, these values were significantly different (P<0.0001). Using semi-automated ROIs, the %ID was 4.38±0.160 for three operators. No significant difference was observed. Complete reproducibility was shown in 58 of 59 kidneys; the %ID difference of the remaining kidney was only 1.2%. The lowest %ID of all the kidneys successfully detected using the semi-automated method was 0.77%. The semi-automated renal ROI selection method using the double-threshold technique displays good detectability of the renal contour. The renal uptake calculated using this method is reproducible and acceptable in routine clinical practice. (orig.)

  4. Missing Oral Health-Related Data in the interRAI-HC - Associations with Selected Variables of General Health and the Effect of Multiple Imputation on the Relationship between Oral and General Health.

    Science.gov (United States)

    Krausch-Hofmann, Stefanie; Bogaerts, Kris; Hofmann, Michael; de Almeida Mello, Johanna; Fávaro Moreira, Nádia Cristina; Lesaffre, Emmanuel; Declerck, Dominique; Declercq, Anja; Duyck, Joke

    2015-01-01

    Missing data within the comprehensive geriatric assessment of the interRAI suite of assessment instruments potentially imply the under-detection of conditions that require care as well as the risk of biased statistical results. Impaired oral health in older individuals has to be registered accurately as it causes pain and discomfort and is related to the general health status. This study was based on interRAI-Home Care (HC) baseline data from 7590 subjects (mean age 81.2 years, SD 6.9) in Belgium. It was investigated if missingness of the oral health-related items was associated with selected variables of general health. It was also determined if multiple imputation of missing data affected the associations between oral and general health. Multivariable logistic regression was used to determine if the prevalence of missingness in the oral health-related variables was associated with activities of daily life (ADLH), cognitive performance (CPS2) and depression (DRS). Associations between oral health and ADLH, CPS2 and DRS were determined, with missing data treated by 1. the complete-case technique and 2. by multiple imputation, and results were compared. The individual oral health-related variables had a similar proportion of missing values, ranging from 16.3% to 17.2%. The prevalence of missing data in all oral health-related variables was significantly associated with symptoms of depression (dental prosthesis use OR 1.66, CI 1.41-1.95; damaged teeth OR 1.74, CI 1.48-2.04; chewing problems OR 1.74, CI 1.47-2.05; dry mouth OR 1.65, CI 1.40-1.94). Missingness in damaged teeth (OR 1.27, CI 1.08-1.48), chewing problems (OR 1.22, CI 1.04-1.44) and dry mouth (OR 1.23, CI 1.05-1.44) occurred more frequently in cognitively impaired subjects. ADLH was not associated with the prevalence of missing data. When comparing the complete-case technique with the multiple imputation approach, nearly identical odds ratios characterized the associations between oral and general health

  5. Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain).

    Science.gov (United States)

    Peña-Fernández, A; Lobo-Bedmar, M C; González-Muñoz, M J

    2015-01-01

    Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Environmental and Physiographic Controls on Inter-Growing Season Variability of Carbon Dioxide and Water Vapour Fluxes in a Minerotrophic Fen

    Science.gov (United States)

    van der Kamp, G.; Sonnentag, O.; Chen, J. M.; Barr, A.; Hedstrom, N.; Granger, R.

    2008-12-01

    The interaction of fens with groundwater is spatially and temporally highly variable in response to meteorological conditions, resulting in frequent changes of groundwater fluxes in both vertical and lateral directions (flow reversals) across the mineral soil-peat boundary. However, despite the importance of the topographic and hydrogeological setting of fens, no study has been reported in the literature that explores a fen's atmospheric CO2 and energy flux densities under contrasting meteorological conditions in response to its physiographic setting. In our contribution we report four years of growing season eddy covariance and supporting measurements from the Canada Fluxnet-BERMS fen (formerly BOREAS southern peatland) in Saskatchewan, Canada. We first analyze hydrological data along two piezometer transects across the mineral soil-peat boundary with the objective of assessing changes in water table configuration and thus hydraulic gradients, indicating flow reversals, in response to dry and wet meteorological conditions. Next we quantify and compare growing season totals and diurnal and daily variations in evapotranspiration (ET) and net ecosystem exchange (NEE) and its component fluxes gross ecosystem productivity (GPP) and terrestrial ecosystem respiration (TER) to identify their controls with a major focus on water table depth. While ET growing season totals were similar (~ 310 mm) under dry and wet meteorological conditions, the CO2 sink- source strength of Sandhill fen varied substantially from carbon neutral (NEE = -2 [+-7] g C m-2 per growing season) under dry meteorological condition (2003) to a moderate CO2- sink with NEE ranging between 157 [+- 10] and 190 [+- 11] g C m-2 per growing season under wet meteorological conditions (2004, 2005, and 2006). Using a process-oriented ecosystem model, BEPS-TerrainLab, we investigate how different canopy components at Sandhill contribute to total ET and GPP, and thus water use efficiency, under dry and wet

  7. Intra-clutch and inter-colony variability in element concentrations in eggshells of the black-headed gull, Chroicocephalus ridibundus, in northern Poland.

    Science.gov (United States)

    Kitowski, Ignacy; Indykiewicz, Piotr; Wiącek, Dariusz; Jakubas, Dariusz

    2017-04-01

    Eggshells are good bioindicators of environmental contamination, and therefore, the concentrations of 17 trace elements in 87 eggshells of black-headed gulls, Chroicocephalus ridibundus, were determined in five breeding colonies in an area dominated by farmland in northern Poland. The intra-clutch variability in the eggshell concentrations of heavy metals and other elements was also investigated, and the concentrations of the elements showed the following pattern: Ca > Mg > Sr > Fe > Zn > Al > Cr > Se > Mn > Cu > Pb > As > Ni > Mo = V > Sc > Cd. The concentrations of Fe, Al, and Mn decreased with the order in which the eggs were laid, but Sr concentrations increased. In contrast, the concentration of Cu significantly increased with the laying date. The concentrations of all elements significantly differed among the studied colonies; the highest concentration of eight elements was found in the eggshells from the Kusowo colony, which may have resulted from the intensive use of fertilizers, manure, and slurry in the surrounding agricultural region. The concentrations of Mg, Sr, and Zn in the eggshells from Skoki Duże were higher than those of the other studied colonies, which may have occurred because the gulls were nesting in a functioning gravel pit; soil and the parent rock are natural reservoirs of these elements. The observed element levels indicate that the environment where the black-headed gull eggs were formed, i.e., primarily near the breeding colonies, remains in a relatively unpolluted state, which was reflected by the low levels of Cd, Ni, and Pb and the lack of measurable levels of Hg.

  8. Annual and Seasonal hydroclimatology of the Athabasca River in the context of major modes of climatic variability

    Science.gov (United States)

    Peters, D. L.; Atkinson, D. E.; Baird, D.; Monk, W.; Tenenbaum, D.

    2011-12-01

    The Athabasca River in northwestern Canada, the dominant inflow to Lake Athabasca and Peace-Athabasca Delta complex, continues to be influenced by multiple environmental stressors on its hydrology and aquatic ecology, including land-use change, climate variability/change, and growing industrial water demand. The Athabasca River presents a good opportunity to examine the impact of Pacific climatic variability on the hydroclimatolgy and flow generation because it has some good data sets, it is an unregulated river, and it represents the more climatically subtle northern mid-continental region. Further, recent industrial activities in this watershed give a pragmatic edge to research on this watershed. This project addresses the Athabasca River watershed as a unit, utilizing a recently compiled dataset of hydrometric and climatic station data assessed for long-term trends in runoff and for linkages between hydroclimatic parameters with documented major modes of climatic variability. Daily flow data from stations along the Athabasca River were extracted from the Environment Canada HYDAT archive. Where possible patchy records from nearby stations were merged and brief gaps in-filled, resulting in an optimized set of four data series: Hinton (1915-2008, ), Athabasca (1913-2008), Fort McMurray (1957-2008), and Embarras (1957-2008). Identification of long-term trends was performed using a Mann-Kendall test: all stations showed decreasing trends in median runoff for the open-water season (May-Oct) 1958-2009; Hinton showed a strong decreasing trends for the 1913-2009 period. Runoff during the ice-on season at Hinton was weakly positive, the only station/season to show a positive trend. Initial results for comparisons with indices of climate variability that have been previously demonstrated to exert influence on various aspects of western hydroclimatology (e.g. PNA, PDO, various ENSO, NP) show expected strong to moderate correlations (Kendall-Tau) with air temperature and

  9. A framework for assessing inter-individual variability in pharmacokinetics using virtual human populations and integrating general knowledge of physical chemistry, biology, anatomy, physiology and genetics: A tale of 'bottom-up' vs 'top-down' recognition of covariates.

    Science.gov (United States)

    Jamei, Masoud; Dickinson, Gemma L; Rostami-Hodjegan, Amin

    2009-01-01

    An increasing number of failures in clinical stages of drug development have been related to the effects of candidate drugs in a sub-group of patients rather than the 'average' person. Expectation of extreme effects or lack of therapeutic effects in some subgroups following administration of similar doses requires a full understanding of the issue of variability and the importance of identifying covariates that determine the exposure to the drug candidates in each individual. In any drug development program the earlier these covariates are known the better. An important component of the drive to decrease this failure rate in drug development involves attempts to use physiologically-based pharmacokinetics 'bottom-up' modeling and simulation to optimize molecular features with respect to the absorption, distribution, metabolism and elimination (ADME) processes. The key element of this approach is the separation of information on the system (i.e. human body) from that of the drug (e.g. physicochemical characteristics determining permeability through membranes, partitioning to tissues, binding to plasma proteins or affinities toward certain enzymes and transporter proteins) and the study design (e.g. dose, route and frequency of administration, concomitant drugs and food). In this review, the classical 'top-down' approach in covariate recognition is compared with the 'bottom-up' paradigm. The determinants and sources of inter-individual variability in different stages of drug absorption, distribution, metabolism and excretion are discussed in detail. Further, the commonly known tools for simulating ADME properties are introduced.

  10. Annual report June 1988

    International Nuclear Information System (INIS)

    1988-01-01

    This annual report reviews the activities of the National Accelerator Centre until June 1988. The 200 MeV cyclotron facility, the Pretoria cyclotron facility and the Van De Graaff facility are discussed in detail. Aspects of the 200 MeV cyclotron facility examined are, inter alia: the injector cyclotrons, the separated-sector cyclotron, the control system, the beam transport system and radioisotope production. Separate abstracts were prepared for the various subdivisions contained in this annual report

  11. Annual variability in light absorption by particles and colored dissolved organic matter in the Crimean coastal waters (the Black Sea)

    Science.gov (United States)

    Churilova, T.; Moiseeva, N.; Efimova, T.; Suslin, V.; Krivenko, O.; Zemlianskaia, E.

    2017-11-01

    Bio-optical studies were carried out in coastal waters around the Crimea peninsula in different seasons 2016. It was shown that variability of chlorophyll a concentration (Chl-a), light absorption by suspended particles (ap(λ)), phytoplankton pigments (aph(λ)), non-algal particles (aNAP(λ)) and by colored dissolved organic matter (aCDOM(λ)) in the Crimea coastal water was high ( order of magnitudes) in all seasons 2016. Relationships between ap(440), aph(440) and Chl-a were obtained and their seasonal differences were analyzed. Spectral distribution of aNAP(λ) and aCDOM(λ) were parameterized. Seasonality in aCDOM(λ) parameterization was revealed, but - in aNAP(λ) parameterization was not revealed. The budget of light absorption by aph(λ), aNAP(λ) i aCDOM(λ) at 440 nm was assessed and its seasonal dynamics was analyzed.

  12. THE EVOLUTION OF ANNUAL MEAN TEMPERATURE AND PRECIPITATION QUANTITY VARIABILITY BASED ON ESTIMATED CHANGES BY THE REGIONAL CLIMATIC MODELS

    Directory of Open Access Journals (Sweden)

    Paula Furtună

    2013-03-01

    Full Text Available Climatic changes are representing one of the major challenges of our century, these being forcasted according to climate scenarios and models, which represent plausible and concrete images of future climatic conditions. The results of climate models comparison regarding future water resources and temperature regime trend can become a useful instrument for decision makers in choosing the most effective decisions regarding economic, social and ecologic levels. The aim of this article is the analysis of temperature and pluviometric variability at the closest grid point to Cluj-Napoca, based on data provided by six different regional climate models (RCMs. Analysed on 30 year periods (2001-2030,2031-2060 and 2061-2090, the mean temperature has an ascending general trend, with great varability between periods. The precipitation expressed trough percentage deviation shows a descending general trend, which is more emphazied during 2031-2060 and 2061-2090.

  13. Modelling deposition and air concentration of reduced nitrogen in Poland and sensitivity to variability in annual meteorology.

    Science.gov (United States)

    Kryza, Maciej; Dore, Anthony J; Błaś, Marek; Sobik, Mieczysław

    2011-04-01

    The relative contribution of reduced nitrogen to acid and eutrophic deposition in Europe has increased recently as a result of European policies which have been successful in reducing SO(2) and NO(x) emissions but have had smaller impacts on ammonia (NH(3)) emissions. In this paper the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model was used to calculate the spatial patterns of annual average ammonia and ammonium (NH(4)(+)) air concentrations and reduced nitrogen (NH(x)) dry and wet deposition with a 5 km × 5 km grid for years 2002-2005. The modelled air concentrations of NH(3) and dry deposition of NH(x) show similar spatial patterns for all years considered. The largest year to year changes were found for wet deposition, which vary considerably with precipitation amount. The FRAME modelled air concentrations and wet deposition are in reasonable agreement with available measurements (Pearson's correlation coefficients above 0.6 for years 2002-2005), and with spatial patterns of concentrations and deposition of NH(x) reported with the EMEP results, but show larger spatial gradients. The error statistics show that the FRAME model results are in better agreement with measurements if compared with EMEP estimates. The differences in deposition budgets calculated with FRAME and EMEP do not exceed 17% for wet and 6% for dry deposition, with FRAME estimates higher than for EMEP wet deposition for modelled period and lower or equal for dry deposition. The FRAME estimates of wet deposition budget are lower than the measurement-based values reported by the Chief Inspectorate of Environmental Protection of Poland, with the differences by approximately 3%. Up to 93% of dry and 53% of wet deposition of NH(x) in Poland originates from national sources. Over the western part of Poland and mountainous areas in the south, transboundary transport can contribute over 80% of total (dry + wet) NH(x) deposition. The spatial pattern of the relative contribution of

  14. Temporal variability and annual budget of inorganic dissolved matter in Andean Pacific Rivers located along a climate gradient from northern Ecuador to southern Peru

    Science.gov (United States)

    Moquet, Jean-Sébastien; Guyot, Jean-Loup; Morera, Sergio; Crave, Alain; Rau, Pedro; Vauchel, Philippe; Lagane, Christelle; Sondag, Francis; Lavado, Casimiro Waldo; Pombosa, Rodrigo; Martinez, Jean-Michel

    2018-01-01

    In Ecuador and Peru, geochemical information from Pacific coastal rivers is limited and scarce. Here, we present an unedited database of major element concentrations from five HYBAM observatory stations monitored monthly between 4 and 10 years, and the discrete sampling of 23 Andean rivers distributed along the climate gradient of the Ecuadorian and Peruvian Pacific coasts. Concentration (C) vs. discharge (Q) relationships of the five monitored basins exhibit a clear dilution behavior for evaporites and/or pyrite solutes, while the solute concentrations delivered by other endmembers are less variable. Spatially, the annual specific fluxes for total dissolved solids (TDS), Ca2+, HCO3-, K+, Mg2+, and SiO2 are controlled on the first order by runoff variability, while Cl-, Na+ and SO42- are controlled by the occurrence of evaporites and/or pyrite. The entire Pacific basin in Ecuador and Peru exported 30 Mt TDS·yr-1, according to a specific flux of ∼70 t·km-2·yr-1. This show that, even under low rainfall conditions, this orogenic context is more active, in terms of solute production, than the global average.

  15. Variability of the date of monsoon onset over Kerala (India) of the ...

    Indian Academy of Sciences (India)

    We found that SST anomalies of large spatial scale similar to those in El Nino/La Nina are associated with the inter-annual variability in DMOK. Indian Ocean between latitudes 5∘S and 20∘N has two episodes of active convection associated with monsoon onset over Kerala (MOK), one around DMOK and the other about ...

  16. Variability and quasi-decadal changes in the methane budget over the period 2000-2012

    NARCIS (Netherlands)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; Weiss, Ray; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

    2017-01-01

    Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH4) budget over 2000-2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies

  17. Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest

    Science.gov (United States)

    Tana Wood; M. Detto; W.L. Silver

    2013-01-01

    Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m2), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal...

  18. Inter-Asian Variability in Intergenerational Communication

    Science.gov (United States)

    Ota, Hiroshi; McCann, Robert M.; Honeycutt, James M.

    2012-01-01

    This study compared Japanese and Thai younger adults' intra- and intergenerational communication. Both groups linearly increased communicative respect and avoidance, beliefs about politeness, and deference norms as interlocutors got older (from young to middle-aged to older adult). Cross-culturally, the Thais reported more respectful communication…

  19. Spatiotemporal variability in carbon exchange fluxes across the Sahel

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Fensholt, Rasmus; Cappelaere, Bernard

    2016-01-01

    variability in these fluxes and to analyse to which degree spatiotemporal variation can be explained by hydrological, climatic, edaphic and vegetation variables. All ecosystems were C sinks (average ± total error -162 ± 48 g C m-2 y-1), but were smaller when strongly impacted by anthropogenic influences....... Spatial and inter-annual variability in the C flux processes indicated a strong resilience to dry conditions, and were correlated with phenological metrics. Gross primary productivity (GPP) was the most important flux process affecting the sink strength, and diurnal variability in GPP was regulated...

  20. Annual mean sea level and its sensitivity to wind climate

    Science.gov (United States)

    Gerkema, Theo; Duran Matute, Matias

    2017-04-01

    Changes in relative mean sea level affect coastal areas in various ways, such as the risk of flooding, the evolution of barrier island systems, or the development of salt marshes. Long-term trends in these changes are partly masked by variability on shorter time scales. Some of this variability, for instance due to wind waves and tides (with the exception of long-period tides), is easily averaged out. In contrast, inter-annual variability is found to be irregular and large, of the order of several decimeters, as is evident from tide gauge records. This is why the climatic trend, typically of a few millimeters per year, can only be reliably identified by examining a record that is long enough to outweigh the inter-annual and decadal variabilities. In this presentation we examine the relation between the annual wind conditions from meteorological records and annual mean sea level along the Dutch coast. To do this, we need reliable and consistent long-term wind records. Some wind records from weather stations in the Netherlands date back to the 19th century, but they are unsuitable for trend analysis because of changes in location, height, surroundings, instrument type or protocol. For this reason, we will use only more recent, homogeneous wind records, from the past two decades. The question then is whether such a relatively short record is sufficient to find a convincing relation with annual mean sea level. It is the purpose of this work to demonstrate that the answer is positive and to suggest methods to find and exploit such a relation. We find that at the Dutch coast, southwesterly winds are dominant in the wind climate, but the west-east direction stands out as having the highest correlation with annual mean sea level. For different stations in the Dutch Wadden Sea and along the coast, we find a qualitatively similar pattern, although the precise values of the correlations vary. The inter-annual variability of mean sea level can already be largely explained by

  1. The influence of riparian woodland on the spatial and temporal variability of stream water temperatures in an upland salmon stream

    Directory of Open Access Journals (Sweden)

    I. A. Malcolm

    2004-01-01

    Full Text Available The spatio-temporal variability of stream water temperatures was investigated at six locations on the Girnock Burn (30km2 catchment, Cairngorms, Scotland over three hydrological years between 1998 and 2002. The key site-specific factors affecting the hydrology and climatology of the sampling points were investigated as a basis for physical process inference. Particular emphasis was placed on assessing the effects of riparian forest in the lower catchment versus the heather moorland riparian zones that are spatially dominant in the upper catchment. The findings were related to river heat budget studies that provided process detail. Gross changes in stream temperature were affected by the annual cycle of incoming solar radiation and seasonal changes in hydrological and climatological conditions. Inter-annual variation in these controlling variables resulted in inter-annual variability in thermal regime. However, more subtle inter-site differences reflected the impact of site-specific characteristics on various components of the river energy budget. Inter-site variability was most apparent at shorter time scales, during the summer months and for higher stream temperatures. Riparian woodland in the lower catchment had a substantial impact on thermal regime, reducing diel variability (over a period of 24 hours and temperature extremes. Observed inter-site differences are likely to have a substantial effect on freshwater ecology in general and salmonid fish in particular. Keywords: temperature, thermal regime, forest, salmon, hydrology, Girnock Burn, Cairngorm

  2. The time window of MRI of murine atherosclerotic plaques after administration of CB2 receptor targeted micelles: inter-scan variability and relation between plaque signal intensity increase and gadolinium content of inversion recovery prepared versus non-prepared fast spin echo

    NARCIS (Netherlands)

    te Boekhorst, B. C. M.; Bovens, S. M.; van de Kolk, C. W. A.; Cramer, M. J. M.; Doevendans, P. A. F. M.; ten Hove, M.; van der Weerd, L.; Poelmann, R.; Strijkers, G. J.; Pasterkamp, G.; van Echteld, C. J. A.

    2010-01-01

    Single fast spin echo scans covering limited time frames are mostly used for contrast-enhanced MRI of atherosclerotic plaque biomarkers. Knowledge on inter-scan variability of the normalized enhancement ratio of plaque (NER(plaque)) and relation between NER(plaque) and gadolinium content for

  3. Inter-rater variability of visual interpretation and comparison with quantitative evaluation of 11C-PiB PET amyloid images of the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) multicenter study

    International Nuclear Information System (INIS)

    Yamane, Tomohiko; Ishii, Kenji; Sakata, Muneyuki; Ikari, Yasuhiko; Nishio, Tomoyuki; Ishii, Kazunari; Kato, Takashi; Ito, Kengo; Senda, Michio

    2017-01-01

    The aim of this study was to assess the inter-rater variability of the visual interpretation of 11 C-PiB PET images regarding the positivity/negativity of amyloid deposition that were obtained in a multicenter clinical research project, Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI). The results of visual interpretation were also compared with a semi-automatic quantitative analysis using mean cortical standardized uptake value ratio to the cerebellar cortex (mcSUVR). A total of 162 11 C-PiB PET scans, including 45 mild Alzheimer's disease, 60 mild cognitive impairment, and 57 normal cognitive control cases that had been acquired as J-ADNI baseline scans were analyzed. Based on visual interpretation by three independent raters followed by consensus read, each case was classified into positive, equivocal, and negative deposition (ternary criteria) and further dichotomized by merging the former two (binary criteria). Complete agreement of visual interpretation by the three raters was observed for 91.3% of the cases (Cohen κ = 0.88 on average) in ternary criteria and for 92.3% (κ = 0.89) in binary criteria. Cases that were interpreted as visually positive in the consensus read showed significantly higher mcSUVR than those visually negative (2.21 ± 0.37 vs. 1.27 ± 0.09, p < 0.001), and positive or negative decision by visual interpretation was dichotomized by a cut-off value of mcSUVR = 1.5. Significant positive/negative associations were observed between mcSUVR and the number of raters who evaluated as positive (ρ = 0.87, p < 0.0001) and negative (ρ = -0.85, p < 0.0001) interpretation. Cases of disagreement among raters showed generally low mcSUVR. Inter-rater agreement was almost perfect in 11 C-PiB PET scans. Positive or negative decision by visual interpretation was dichotomized by a cut-off value of mcSUVR = 1.5. As some cases of disagreement among raters tended to show low mcSUVR, referring to quantitative method may facilitate

  4. Inter-rater variability of visual interpretation and comparison with quantitative evaluation of {sup 11}C-PiB PET amyloid images of the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Tomohiko [Saitama Medical University Saitama International Center, Department of Nuclear Medicine, Hidaka (Japan); Institute of Biomedical Research and Innovation, Division of Molecular Imaging, Kobe (Japan); Tokyo Metropolitan Institute of Gerontology, Team for Neuroimaging Research, Tokyo (Japan); Ishii, Kenji; Sakata, Muneyuki [Tokyo Metropolitan Institute of Gerontology, Team for Neuroimaging Research, Tokyo (Japan); Ikari, Yasuhiko; Nishio, Tomoyuki [Institute of Biomedical Research and Innovation, Division of Molecular Imaging, Kobe (Japan); Research Association for Biotechnology, Tokyo (Japan); Ishii, Kazunari [Kinki University Hospital, Department of Radiology, Osaka, Sayama (Japan); Kato, Takashi; Ito, Kengo [National Center for Geriatrics and Gerontology, Department of Brain Science and Molecular Imaging, Obu (Japan); Senda, Michio [Institute of Biomedical Research and Innovation, Division of Molecular Imaging, Kobe (Japan); Collaboration: J-ADNI Study Group

    2017-05-15

    The aim of this study was to assess the inter-rater variability of the visual interpretation of {sup 11}C-PiB PET images regarding the positivity/negativity of amyloid deposition that were obtained in a multicenter clinical research project, Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI). The results of visual interpretation were also compared with a semi-automatic quantitative analysis using mean cortical standardized uptake value ratio to the cerebellar cortex (mcSUVR). A total of 162 {sup 11}C-PiB PET scans, including 45 mild Alzheimer's disease, 60 mild cognitive impairment, and 57 normal cognitive control cases that had been acquired as J-ADNI baseline scans were analyzed. Based on visual interpretation by three independent raters followed by consensus read, each case was classified into positive, equivocal, and negative deposition (ternary criteria) and further dichotomized by merging the former two (binary criteria). Complete agreement of visual interpretation by the three raters was observed for 91.3% of the cases (Cohen κ = 0.88 on average) in ternary criteria and for 92.3% (κ = 0.89) in binary criteria. Cases that were interpreted as visually positive in the consensus read showed significantly higher mcSUVR than those visually negative (2.21 ± 0.37 vs. 1.27 ± 0.09, p < 0.001), and positive or negative decision by visual interpretation was dichotomized by a cut-off value of mcSUVR = 1.5. Significant positive/negative associations were observed between mcSUVR and the number of raters who evaluated as positive (ρ = 0.87, p < 0.0001) and negative (ρ = -0.85, p < 0.0001) interpretation. Cases of disagreement among raters showed generally low mcSUVR. Inter-rater agreement was almost perfect in {sup 11}C-PiB PET scans. Positive or negative decision by visual interpretation was dichotomized by a cut-off value of mcSUVR = 1.5. As some cases of disagreement among raters tended to show low mcSUVR, referring to quantitative method may

  5. Appendix A.3. Minutes from meeting of the 1995th Joint Annual Report's Proposals and on the Slovak-Hungarian monitoring of underwater weir impacts according to the Inter-governmental Agreement held on October 10, 1996 in Gyoer

    International Nuclear Information System (INIS)

    1997-01-01

    This part contains: (1) Points of the agenda: 1. Evaluation of the water discharged by the Slovak Party according to the Agreement from 1995; 2. Information about the monitoring data exchange: - surface and groundwater regimes in 1996, - surface and ground water quality, - soil moisture, - bio-monitoring including Proposals in the 1995 th Joint Annual Report; 3 Schedule of the 1995 th Joint Annual Report's proposals fulfillment; 4 Tasks concerning the 1996 th National and Annual Reports preparation. In the annexes tabular forms and digital formats for data exchange are presented: Surface water discharge; Surface water level; Surface water quality, Ground Water level; Ground Water quality; Soil moisture. (2) Annex 1: Minutes from meeting of experts for surface and ground water regime and quality held on September 11, 1996 in Bratislava. (3) Annex 2: Minutes from meeting of experts for soil moisture monitoring and biology held on October 2, 1996 in Mosonmagyarovar

  6. Quantifying the increasing sensitivity of power systems to climate variability

    Science.gov (United States)

    Bloomfield, H. C.; Brayshaw, D. J.; Shaffrey, L. C.; Coker, P. J.; Thornton, H. E.

    2016-12-01

    Large quantities of weather-dependent renewable energy generation are expected in power systems under climate change mitigation policies, yet little attention has been given to the impact of long term climate variability. By combining state-of-the-art multi-decadal meteorological records with a parsimonious representation of a power system, this study characterises the impact of year-to-year climate variability on multiple aspects of the power system of Great Britain (including coal, gas and nuclear generation), demonstrating why multi-decadal approaches are necessary. All aspects of the example system are impacted by inter-annual climate variability, with the impacts being most pronounced for baseload generation. The impacts of inter-annual climate variability increase in a 2025 wind-power scenario, with a 4-fold increase in the inter-annual range of operating hours for baseload such as nuclear. The impacts on peak load and peaking-plant are comparably small. Less than 10 years of power supply and demand data are shown to be insufficient for providing robust power system planning guidance. This suggests renewable integration studies—widely used in policy, investment and system design—should adopt a more robust approach to climate characterisation.

  7. Sub-annual North Pacific hydroclimate variability since 1450AD from updated St. Elias ice core isotope and accumulation rate records

    Science.gov (United States)

    Kreutz, K. J.; Campbell, S. W.; Winski, D.; Osterberg, E. C.; Kochtitzky, W. H.; Copland, L.; Dixon, D.; Introne, D.; Medrzycka, D.; Main, B.; Bernsen, S.; Wake, C. P.

    2017-12-01

    A growing array of high-resolution paleoclimate records from the terrestrial region bordering the Gulf of Alaska (GoA) continues to reveal details about ocean-atmosphere variability in the region during the Common Era. Ice core records from high-elevation ranges in proximity to the GoA provide key information on extratropical hydroclimate, and potential teleconnections to low latitude regions. In particular, stable water isotope and snow accumulation reconstructions from ice cores collected in high precipitation locations are uniquely tied to regional water cycle changes. Here we present new data collected in 2016 and 2017 from the St. Elias Mountains (Eclipse Icefield, Yukon Territories, Canada), including a range of ice core and geophysical measurements. Low- and high-frequency ice penetrating radar data enable detailed mapping of icefield bedrock topography and internal reflector stratigraphy. The 1911 Katmai eruption layer can be clearly traced across the icefield, and tied definitively to the coeval ash layer found in the 345 meter ice core drilled at Eclipse Icefield in 2002. High-resolution radar data are used to map spatial variability in 2015/16 and 2016/17 snow accumulation. Ice velocity data from repeat GPS stake measurements and remote sensing feature tracking reveal a clear divide flow regime on the icefield. Shallow firn/ice cores (20 meters in 2017 and 65 meters in 2016) are used to update the 345 meter ice core drilled at Eclipse Icefield in 2002. We use new algorithm-based layer counting software to improve and provide error estimates on the new ice core chronology, which extends from 2017 to 1450AD. 3D finite element modeling, incorporating all available geophysical data, is used to refine the reconstructed accumulation rate record and account for vertical and horizontal ice flow. Together with high-resolution stable water isotope data, the updated Eclipse record provides detailed, sub-annual resolution data on several aspects of the regional

  8. [Inter-session-processes].

    Science.gov (United States)

    Zeeck, Almut; Hartmann, Armin; Orlinsky, David

    2004-06-01

    We do not know much about how patients internalize, remember or use psychotherapeutic experiences between psychotherapy sessions and how they use them for change. What happens with in-session-experiences after a session ("inter-session-process") is of main importance for outcome. The inter-session-process describes the work on psychotherapy between sessions. Although inter-session-processes are a central element connecting psychotherapy process and outcome, they remain a neglected area of research. Previous studies examined individual outpatient settings only. This paper gives an overview over theory, instruments for measurement, previous studies and relevance of inter-session-processes for the field of psychotherapy research.

  9. Diurnal Evolution and Annual Variability of Boundary Layer Height in the Columbia River Gorge through the `Eye' of Wind Profiling Radars

    Science.gov (United States)

    Bianco, L.; Djalalova, I.; Konopleva-Akish, E.; Kenyon, J.; Olson, J. B.; Wilczak, J. M.

    2016-12-01

    The Second Wind Forecast Improvement Project (WFIP2) is a DoE- and NOAA-sponsored program whose goal is to improve the accuracy of numerical weather prediction (NWP) forecasts in complex terrain. WFIP2 consists of an 18-month (October 2015 - March 2017) field campaign held in the Columbia River basin, in the Pacific Northwest of the U.S. As part of WFIP2 a large suite of in-situ and remote sensing instrumentation has been deployed, including, among several others, a network of eight 915-MHz wind profiling radars (WPRs) equipped with radio acoustic sounding systems (RASSs), and many surface meteorological stations. The diurnal evolution and annual variability of boundary layer height in the area of WFIP2 will be investigated through the `eye' of WPRs, employing state-of-the-art automated algorithms, based on fuzzy logic and artificial intelligence. The results will be used to evaluate possible errors in NWP models in this area of complex terrain.

  10. Results of the 1999-2000 collaborative exercise and proficiency testing program on mitochondrial DNA of the GEP-ISFG: an inter-laboratory study of the observed variability in the heteroplasmy level of hair from the same donor.

    Science.gov (United States)

    Alonso, Antonio; Salas, Antonio; Albarrán, Cristina; Arroyo, Eduardo; Castro, Azucena; Crespillo, Manuel; di Lonardo, Ana María; Lareu, María Victoria; Cubría, Carlos López; Soto, Manuel López; Lorente, José A; Semper, Marta Montesino; Palacio, Ana; Paredes, Manuel; Pereira, Luisa; Lezaun, Anna Pérez; Brito, José Pestano; Sala, Andrea; Vide, María Conceiçao; Whittle, Martín; Yunis, Juan J; Gómez, Josefina

    2002-01-24

    The Spanish and Portuguese working group (GEP) of international society for forensic genetics (ISFG) 1999-2000 collaborative exercise on mitochondrial DNA (mtDNA) included the analysis of four bloodstain samples and one hair shaft sample by 19 participating laboratories from Spain, Portugal and several Latin-American countries. A wide range of sequence results at position 16,093 of the HV1 (from T or C homoplasmy to different levels of heteroplasmy) were submitted by the different participating laboratories from the hair shaft sample during the first phase of this exercise. During the discussion of these results in the Annual GEP-ISFG 2000 Conference a second phase of this exercise was established with two main objectives: (i) to evaluate the incidence of the HV1 sequence heteroplasmy detected in Phase I across different sample types from the same donor including blood, saliva, and hair shafts, (ii) to perform a technical review of the electropherograms to evaluate the relative levels of heteroplasmies obtained by the different laboratories and also to examine the source of possible errors detected in Phase I. Anonymous review of the raw sequence data permitted the detection of three transcription errors and three errors due to methodological problems. Highly variable levels of heteroplasmy were found in the hair shaft and more stability in blood and saliva. Three laboratories found variable levels of heteroplasmy at position 16,093 across adjacent fragments from the same hair shaft. Two laboratories also described more than one heteroplasmic position from a single hair. The relevance of these findings for the interpretation of mtDNA data in the forensic context is also discussed.

  11. Análisis comparativo de los diferentes índices de referencia empleados en los préstamos contratados a tipo de interés variable

    Directory of Open Access Journals (Sweden)

    Soto Alvarez, José Manuel

    1998-01-01

    Full Text Available El Banco de España, en la Circular nº 5/1994 de 22 de Julio, reconoce como oficiales a efectos de la contratación de préstamos hipotecarios a tipo de interés variable, los siguientes índices o tipos de referencia: a tipo medio de los préstamos hipotecarios a más de tres años, para adquisición de vivienda libre concedidos por los bancos; b tipo medio de los préstamos hipotecarios a más de tres años, para adquisición de vivienda libre concedidos por las cajas de ahorro; c tipo medio de los préstamos hipotecarios a más de tres años, para adquisición de vivienda libre concedidos por el conjunto de las entidades de crédito; d tipo activo de referencia de las cajas de ahorro; e tipo de rendimiento interno en el mercado secundario de la deuda pública de plazo entre 2 y 6 años; f tipo interbancario a 1 año (MIBOR. La pluralidad de los mismos, ha generado gran confusión entre los potenciales clientes ante la dificultad de discernir sobre la conveniencia de contratar uno u otro. En este trabajo, se realiza un estudio comparativo entre los mismos, que tenga en cuenta no sólo el valor de éstos en cada momento, sino también su volatilidad así como el diferencial aplicable en cada caso, analizando su repercusión desde la perspectiva de los potenciales prestatarios.

  12. Inter-rater variability of visual interpretation and comparison with quantitative evaluation of11C-PiB PET amyloid images of the Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI) multicenter study.

    Science.gov (United States)

    Yamane, Tomohiko; Ishii, Kenji; Sakata, Muneyuki; Ikari, Yasuhiko; Nishio, Tomoyuki; Ishii, Kazunari; Kato, Takashi; Ito, Kengo; Senda, Michio

    2017-05-01

    The aim of this study was to assess the inter-rater variability of the visual interpretation of 11 C-PiB PET images regarding the positivity/negativity of amyloid deposition that were obtained in a multicenter clinical research project, Japanese Alzheimer's Disease Neuroimaging Initiative (J-ADNI). The results of visual interpretation were also compared with a semi-automatic quantitative analysis using mean cortical standardized uptake value ratio to the cerebellar cortex (mcSUVR). A total of 162 11 C-PiB PET scans, including 45 mild Alzheimer's disease, 60 mild cognitive impairment, and 57 normal cognitive control cases that had been acquired as J-ADNI baseline scans were analyzed. Based on visual interpretation by three independent raters followed by consensus read, each case was classified into positive, equivocal, and negative deposition (ternary criteria) and further dichotomized by merging the former two (binary criteria). Complete agreement of visual interpretation by the three raters was observed for 91.3% of the cases (Cohen κ = 0.88 on average) in ternary criteria and for 92.3% (κ = 0.89) in binary criteria. Cases that were interpreted as visually positive in the consensus read showed significantly higher mcSUVR than those visually negative (2.21 ± 0.37 vs. 1.27 ± 0.09, p PiB PET scans. Positive or negative decision by visual interpretation was dichotomized by a cut-off value of mcSUVR = 1.5. As some cases of disagreement among raters tended to show low mcSUVR, referring to quantitative method may facilitate correct diagnosis when evaluating images of low amyloid deposition.

  13. Dominant role of plant physiology in trend and variability of gross primary productivity in North America

    Science.gov (United States)

    Zhou, Sha; Zhang, Yao; Ciais, Philippe; Xiao, Xiangming; Luo, Yiqi; Caylor, Kelly K.; Huang, Yuefei; Wang, Guangqian

    2017-02-01

    Annual gross primary productivity (GPP) varies considerably due to climate-induced changes in plant phenology and physiology. However, the relative importance of plant phenology and physiology on annual GPP variation is not clear. In this study, a Statistical Model of Integrated Phenology and Physiology (SMIPP) was used to evaluate the relative contributions of maximum daily GPP (GPPmax) and the start and end of growing season (GSstart and GSend) to annual GPP variability, using a regional GPP product in North America during 2000-2014 and GPP data from 24 AmeriFlux sites. Climatic sensitivity of the three indicators was assessed to investigate the climate impacts on plant phenology and physiology. The SMIPP can explain 98% of inter-annual variability of GPP over mid- and high latitudes in North America. The long-term trend and inter-annual variability of GPP are dominated by GPPmax both at the ecosystem and regional scales. During warmer spring and autumn, GSstart is advanced and GSend delayed, respectively. GPPmax responds positively to summer temperature over high latitudes (40-80°N), but negatively in mid-latitudes (25-40°N). This study demonstrates that plant physiology, rather than phenology, plays a dominant role in annual GPP variability, indicating more attention should be paid to physiological change under futher climate change.

  14. Use of a forest sapwood area index to explain long-term variability in mean annual evapotranspiration and streamflow in moist eucalypt forests

    Science.gov (United States)

    Benyon, Richard G.; Lane, Patrick N. J.; Jaskierniak, Dominik; Kuczera, George; Haydon, Shane R.

    2015-07-01

    Mean sapwood thickness, measured in fifteen 73 year old Eucalyptus regnans and E. delegatensis stands, correlated strongly with forest overstorey stocking density (R2 0.72). This curvilinear relationship was used with routine forest stocking density and basal area measurements to estimate sapwood area of the forest overstorey at various times in 15 research catchments in undisturbed and disturbed forests located in the Great Dividing Range, Victoria, Australia. Up to 45 years of annual precipitation and streamflow data available from the 15 catchments were used to examine relationships between mean annual loss (evapotranspiration estimated as mean annual precipitation minus mean annual streamflow), and sapwood area. Catchment mean sapwood area correlated strongly (R2 0.88) with catchment mean annual loss. Variation in sapwood area accounted for 68% more variation in mean annual streamflow than precipitation alone (R2 0.90 compared with R2 0.22). Changes in sapwood area accounted for 96% of the changes in mean annual loss observed after forest thinning or clear-cutting and regeneration. We conclude that forest inventory data can be used reliably to predict spatial and temporal variation in catchment annual losses and streamflow in response to natural and imposed disturbances in even-aged forests. Consequently, recent advances in mapping of sapwood area using airborne light detection and ranging will enable high resolution spatial and temporal mapping of mean annual loss and mean annual streamflow over large areas of forested catchment. This will be particularly beneficial in management of water resources from forested catchments subject to disturbance but lacking reliable long-term (years to decades) streamflow records.

  15. Future hotspots of increasing temperature variability in tropical countries

    Science.gov (United States)

    Bathiany, S.; Dakos, V.; Scheffer, M.; Lenton, T. M.

    2017-12-01

    Resolving how climate variability will change in future is crucial to determining how challenging it will be for societies and ecosystems to adapt to climate change. We show that the largest increases in temperature variability - that are robust between state-of-the art climate models - are concentrated in tropical countries. On average, temperature variability increases by 15% per degree of global warming in Amazonia and Southern Africa during austral summer, and by up to 10% °C-1 in the Sahel, India and South East Asia. Southern hemisphere changes can be explained by drying soils, whereas shifts in atmospheric structure play a more important role in the Northern hemisphere. These robust regional changes in variability are associated with monthly timescale events, whereas uncertain changes in inter-annual modes of variability make the response of global temperature variability uncertain. Our results suggest that regional changes in temperature variability will create new inequalities in climate change impacts between rich and poor nations.

  16. INTER SECTOR LABOR MOBILITY IN PALEMBANG, INDONESIA

    Directory of Open Access Journals (Sweden)

    Neneng Miskiyah

    2017-06-01

    Full Text Available This study discusses the inter sector labor mobility in Palembang working in the primary, secondary, and tertiary sectors. In this study, the inter sector labor mobility is divided into three (3 categories: (1 a new sector of new type of job, (2 a new sector of same type of job, and (3 the same sector of same type of job. The data used are the cross section data obtained through field surveys. By using multinomial logistic regression model, the results indicate that the variable income, job experience, education, and the number of family members significantly influence the inter sector labor mobility on category 1 compared to category 3. Meanwhile on category 2 compared to category 3, the variables that significantly influence the mobility are income and job security.

  17. A Moored System for Understanding the Temporal Variability of Prey Fields of Deep Diving Predators off Cape Hatteras and Response to Gulf Stream Fronts

    Science.gov (United States)

    2015-09-30

    Number: N000141310686 http://superpod.ml.duke.edu/ LONG-TERM GOALS Fisheries acoustics are routinely used for biomass and abundance surveys and...will be required every 10-12 months), allowing us to address the seasonality and the inter-annual variability in prey biomass and density in

  18. A switch in the Atlantic Oscillation correlates with inter-annual changes in foraging location and food habits of Macaronesian shearwaters (Puffinus baroli) nesting on two islands of the sub-tropical Atlantic Ocean

    Science.gov (United States)

    Ramos, Jaime A.; Isabel Fagundes, Ana; Xavier, José C.; Fidalgo, Vera; Ceia, Filipe R.; Medeiros, Renata; Paiva, Vitor H.

    2015-10-01

    Changes in oceanographic conditions, shaped by changes in large-scale atmospheric phenomena such as the North Atlantic Oscillation (NAO), alters the structure and functioning of marine ecosystems. Such signals are readily captured by marine top predators, given that their use of foraging habitats and diets change when the NAO changes. In this study we assessed sexual, seasonal and annual (2010/11-2012/13) differences in diet, trophic and isotopic niche (using δ15N and δ13C values of whole blood, 1st primary, 8th secondary and breast feathers), foraging locations and oceanographic variation within foraging areas for Macaronesian shearwaters' (Puffinus baroli) during two years of contrasting NAO values, and between two sub-tropical islands 330 km apart in the North Atlantic Ocean, Cima Islet and Selvagem Grande. These two locations provide contrasting oceanographic foraging regimes for the birds, because the second colony is much closer to the African coast (375 vs 650 km), and, therefore, to the upwelling area of the Canary Current. There was a marked environmental perturbation in 2010/2011, related with a negative NAO Index and lower marine productivity (lower concentration of Chlorophyll a). This event corresponded to the Macaronesian shearwaters feeding farther north and west, which was readily seen in change of both δ15N and δ13C values, and in a higher intake of cephalopods. Diet and stable isotopes did not differ between sexes. Regurgitation analysis indicate a dominance of cephalopods in both islands, but prey fish were important for Selvagem Grande in 2012 and cephalopods for Cima Islet in 2011. Both δ15N and δ13C values were significantly higher for Cima Islet than for Selvagem Grande, irrespective of year, season and tissue sampled. SIBER analysis showed smaller isotopic niches for the breeding period. Our study suggests that during years of poor environmental conditions Macaronesian shearwaters shift their foraging location to more pelagic waters

  19. Inter-Pregnancy Interval

    African Journals Online (AJOL)

    Buchi

    This definition excludes. 1, 2 miscarriage as a preceding pregnancy event. Often the IPI is calculated as ... Inter-pregnancy interval of <6 months was significantly associated with an increased risk of adverse subsequent pregnancy outcomes. Mothers 35 years or older at start of childbearing have the highest risk compared to.

  20. ENSO Related Interannual Lightning Variability from the Full TRMM LIS Lightning Climatology

    Science.gov (United States)

    Clark, Austin; Cecil, Daniel J.

    2018-01-01

    It has been shown that the El Nino/Southern Oscillation (ENSO) contributes to inter-annual variability of lightning production in the tropics and subtropics more than any other atmospheric oscillation. This study further investigated how ENSO phase affects lightning production in the tropics and subtropics. Using the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) and the Oceanic Nino Index (ONI) for ENSO phase, lightning data were averaged into corresponding mean annual warm, cold, and neutral 'years' for analysis of the different phases. An examination of the regional sensitivities and preliminary analysis of three locations was conducted using model reanalysis data to determine the leading convective mechanisms in these areas and how they might respond to the ENSO phases. These processes were then studied for inter-annual variance and subsequent correlation to ENSO during the study period to best describe the observed lightning deviations from year to year at each location.

  1. Modelling annual pasture dynamics: Application to stomatal ozone deposition

    Science.gov (United States)

    González-Fernández, Ignacio; Bermejo, Victoria; Elvira, Susana; Sanz, Javier; Gimeno, Benjamín S.; Alonso, Rocío

    2010-07-01

    Modelling ozone (O 3) deposition for impact risk assessment is still poorly developed for herbaceous vegetation, particularly for Mediterranean annual pastures. High inter-annual climatic variability in the Mediterranean area makes it difficult to develop models characterizing gas exchange behaviour and air pollutant absorption suitable for risk assessment. This paper presents a new model to estimate stomatal conductance (g s) of Trifolium subterraneum, a characteristic species of dehesa pastures. The MEDPAS (MEDiterranean PAStures) model couples 3 modules estimating soil water content (SWC), vegetation growth and gs. The gs module is a reparameterized version of the stomatal component of the EMEP DO 3SE O 3 deposition model. The MEDPAS model was applied to two contrasting years representing typical dry and humid springs respectively and with different O 3 exposures. The MEDPAS model reproduced realistically the gs seasonal and inter-annual variations observed in the field. SWC was identified as the major driver of differences across years. Despite the higher O 3 exposure in the dry year, meteorological conditions favoured 2.1 times higher gs and 56 day longer growing season in the humid year compared to the dry year. This resulted in higher ozone fluxes absorbed by T. subterraneum in the humid year. High inter-family variability was found in gas exchange rates, therefore limiting the relevance of single species O 3 deposition flux modelling for dehesa pastures. Stomatal conductance dynamics at the canopy level need to be considered for more accurate O 3 flux modelling for present and future climate scenarios in the Mediterranean area.

  2. Inter- and intra-annual patterns of Ulva prolifera green tides in the Yellow Sea during 2007-2009, their origin and relationship to the expansion of coastal seaweed aquaculture in China.

    Science.gov (United States)

    Keesing, John K; Liu, Dongyan; Fearns, Peter; Garcia, Rodrigo

    2011-06-01

    The large green-tide events that occurred in the Yellow Sea in 2008 (3489km(2)) and 2009 (4994km(2)) are shown to be novel events preceded only once by a much smaller event in 2007 (82km(2)). The blooms originated in the coastal area of Jiangsu province and spread north-east towards the Shandong Peninsula. The blooms grew at different rates and mesoscale variability in surface winds explained the differences in the spatial and temporal patterns of blooms in 2008 and 2009. The 2009 bloom was tracked to its origin immediately offshore of extensive intertidal flats between Yancheng and Nantong where recent rapid expansion of Porphyra aquaculture has occurred. We review published hypotheses which have been advanced to explain the occurrence of blooms and in light of our findings, we conclude that the accumulation and disposal of waste Ulva prolifera from Porphyra aquaculture rafts is the most likely cause of the blooms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Evaluation of Inter Therapy

    DEFF Research Database (Denmark)

    Pedersen, Inge Nygaard

    2002-01-01

    This article (revised conference lecture from the 10th World Congress of Music Therapy, Oxford July 2002)) emphasizes the evaluation of the training of Inter Therapy for music therapy students at the MA training at Aalborg University. The students take turns in being client and therapist within t...... the same partner constellation. Through this training they learn as a therapeutic method to contain and incorporate experiences from being in the client role into managing the therapist role.......This article (revised conference lecture from the 10th World Congress of Music Therapy, Oxford July 2002)) emphasizes the evaluation of the training of Inter Therapy for music therapy students at the MA training at Aalborg University. The students take turns in being client and therapist within...

  4. Inter-annual chemical stratification in Brazilian natural lakes: meromixis and hypolimnetic memory Estratificação química em lagos naturais brasileiros: meromixia e memória hipolimnética

    Directory of Open Access Journals (Sweden)

    Luciana Gomes Barbosa

    2012-06-01

    Full Text Available AIM: chemical stratification and the patterns of light limitation and nutrients of two natural lakes, one shallow and the other one deep, were comparatively evaluated, both lakes located in the southeast Brazil. METHODS: pH, electrical conductivity, dissolved oxygen, total dissolved solids and nutrients were monthly collected during 5 consecutive years at the vertical profile of the two lakes. RESULTS: multivariate analysis indicated that the long thermal stratification period favored the occurrence of chemical stratification in the two lakes. However, in the deeper lake the stratified thermal profile with high hypolimnetic nutrient concentration, electrical conductivity, total dissolved solids and redox potential indicated that the mixing was not complete even during the annual circulation period, suggesting a slight meromixis and a high chemical stability at the hypolimnion. In the shallower lake, high light attenuation and high availability of nitrogen forms (mainly N-NH4 and phosphorus was observed along the water column, even during stratification. In the deeper lake, N and P co-limitation and low light attenuation coefficients were detected. CONCLUSION: thermal and chemical stratification patterns indicated that the Carioca lake is a shallow, turbid, nutrient rich, whereas the Dom Helvecio lake is a deep, clear, oligotrophic system with a tendency towards meromixis and the isolation of solutes in the hypolimnion. Consequently, meromixis was compared to a "hypolimnetic memory", which was defined, in the case of the deeper lake, as the maintenance of the chemical stratification along the years, during the lake thermal circulation period.OBJETIVO: a estratificação química e os padrões de limitação por luz e nutrientes foram avaliados comparativamente em dois lagos naturais, sendo um raso e o outro profundo no sudeste do Brasil. MÉTODOS: as amostragens de pH, condutividade elétrica, oxigênio dissolvido, sólidos totais dissolvidos e

  5. Occurrence, inter-annual variability and zooplankton-predation impact of the invasive ctenophore Mnemiopsis leidyi and the native jellyfish Aurelia aurita in Limfjorden (Denmark) in 2010 and 2011

    DEFF Research Database (Denmark)

    Riisgaard, Hans Ulrik; Jaspers, Cornelia; Serre, Sandrine

    2012-01-01

    and 2009 and it was found that the additional predation pressure by M. leidyi caused the zooplankton stocks to be severely depressed. Here, we report on the population dynamics and predation impact of M. leidyi and A. aurita in Limfjorden in 2010 and 2011. In 2010, M. leidyi was observed in Limfjorden...... of cydippid larvae increased from west to the central parts thus suggesting rapid reproduction and population-size expansion. The bio-volumes of ctenophores were highest in the central part with 85 ml m-3 in Løgstør Bredning, which may be compared to the greatest mean bio-volume of about 184 ml m-3 observed...... in the Black Sea in 1989 when the zooplankton and fish stocks collapsed. Analysis of available hydrographic data and model calculations indicates that re-invasion of M. leidyi from the North Sea seeded the autumn population in Limfjorden in mid-September...

  6. Annual Research Review: Reaction time variability in ADHD and autism spectrum disorders: measurement and mechanisms of a proposed trans-diagnostic phenotype

    Science.gov (United States)

    Karalunas, Sarah L.; Geurts, Hilde M.; Konrad, Kerstin; Bender, Stephan; Nigg, Joel T.

    2014-01-01

    Background Intraindividual variability in reaction time (RT) has received extensive discussion as an indicator of cognitive performance, a putative intermediate phenotype of many clinical disorders, and a possible trans-diagnostic phenotype that may elucidate shared risk factors for mechanisms of psychiatric illnesses. Scope and Methodology Using the examples of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD), we discuss RT variability. We first present a new meta-analysis of RT variability in ASD with and without comorbid ADHD. We then discuss potential mechanisms that may account for RT variability and statistical models that disentangle the cognitive processes affecting RTs. We then report a second meta-analysis comparing ADHD and non-ADHD children on diffusion model parameters. We consider how findings inform the search for neural correlates of RT variability. Findings Results suggest that RT variability is increased in ASD only when children with comorbid ADHD are included in the sample. Furthermore, RT variability in ADHD is explained by moderate to large increases (d = 0.63–0.99) in the ex-Gaussian parameter τ and the diffusion parameter drift rate, as well as by smaller differences (d = 0.32) in the diffusion parameter of nondecision time. The former may suggest problems in state regulation or arousal and difficulty detecting signal from noise, whereas the latter may reflect contributions from deficits in motor organization or output. The neuroimaging literature converges with this multicomponent interpretation and also highlights the role of top-down control circuits. Conclusion We underscore the importance of considering the interactions between top-down control, state regulation (e.g. arousal), and motor preparation when interpreting RT variability and conclude that decomposition of the RT signal provides superior interpretive power and suggests mechanisms convergent with those implicated using other cognitive

  7. Inter-operability

    International Nuclear Information System (INIS)

    Plaziat, J.F.; Moulin, P.; Van Beurden, R.; Ballet, E.

    2005-01-01

    Building an internal gas market implies establishing harmonized rules for cross border trading between operators. To that effect, the European association EASEE-gas is carrying out standards and procedures, commonly called 'inter-operability'. Set up in 2002, the Association brings together all segments of the gas industry: producers, transporters, distributors, traders and shippers, suppliers, consumers and service providers. This workshop presents the latest status on issues such as barriers to gas trade in Europe, rules and procedures under preparation by EASEE-gas, and the implementation schedule of these rules by operators. This article gathers 5 presentations about this topic given at the gas conference

  8. 1992 Annual report

    International Nuclear Information System (INIS)

    1993-01-01

    Annual report of the Institut de Physique Nucleaire at Orsay (France). The main themes are presented. Concerning experimental research: nuclear structure, ground states and low energy excited states, high excitation energy nuclear states, nuclear matter and nucleus-nucleus collision, intermediate energy nuclear physics, radiochemistry, inter-disciplinary research, scientific information and communication; concerning theoretical physics: particles and fields (formal aspects and hadronic physics), chaotic systems and semi-classical methods, few body problems, nucleus-nucleus scattering, nucleus spectroscopy and clusters, statistical physics and condensed matter; concerning general activities and technological research: accelerators, detectors, applications in cryogenics, data processing, Isolde and Orion equipment

  9. Prospective Study Validating Inter- and Intraobserver Variability of Tissue Compliance Meter in Breast Tissue of Healthy Volunteers: Potential Implications for Patients With Radiation-Induced Fibrosis of the Breast

    International Nuclear Information System (INIS)

    Wernicke, A. Gabriella; Parashar, Bhupesh; Kulidzhanov, Fridon; Riley, Lillian; Christos, Paul J.; Fischer, Andrew; Nori, Dattatreyudu; Chao, K.S. Clifford

    2011-01-01

    Purpose: Accurate detection of radiation-induced fibrosis (RIF) is crucial in management of breast cancer survivors. Tissue compliance meter (TCM) has been validated in musculature. We validate TCM in healthy breast tissue with respect to interobserver and intraobserver variability before applying it in RIF. Methods and Materials: Three medical professionals obtained three consecutive TCM measurements in each of the four quadrants of the right and left breasts of 40 women with no breast disease or surgical intervention. The intraclass correlation coefficient (ICC) assessed interobserver variability. The paired t test and Pearson correlation coefficient (r) were used to assess intraobserver variability within each rater. Results: The median age was 45 years (range, 24-68 years). The median bra size was 35C (range, 32A-40DD). Of the participants, 27 were white (67%), 4 black (10%), 5 Asian (13%), and 4 Hispanic (10%). ICCs indicated excellent interrater reliability (low interobserver variability) among the three raters, by breast and quadrant (all ICC ≥0.99). The paired t test and Pearson correlation coefficient both indicated low intraobserver variability within each rater (right vs. left breast), stratified by quadrant (all r≥ 0.94, p < 0.0001). Conclusions: The interobserver and intraobserver variability is small using TCM in healthy mammary tissue. We are now embarking on a prospective study using TCM in women with breast cancer at risk of developing RIF that may guide early detection, timely therapeutic intervention, and assessment of success of therapy for RIF.

  10. Water quality variability in San Francisco Bay, Some gGeneral lessons from 1996 sampling: 1996 annual report, San Francisco estuary regional monitoring program for trace substances

    Science.gov (United States)

    Cloern, J.E.; Cole, B.E.; Edmunds, J.L.; Baylosis, J.I.

    1997-01-01

    This report describes the results from the 1996 Regional Monitoring Program for Trace Substances (RMP). It is the fourth Annual Report from the RMP which began in 1993 and attempts to synthesize the most obvious data patterns from the last four years. This report includes data from Base Program monitoring activities, as well as results of Pilot and Special Studies conducted or completed in 1996. Additionally, several articles contributed by RMP investigators and others, are included. These articles provide perspective and insight on important contaminant issues identified by the RMP. This summary addresses which kinds of pollutants measured by the RMP appear to be at levels that warrant concern, what kinds of trends may be discerned, and which stations have consistently shown elevated contaminant levels. The goals or general objectives of the RMP are: 1. To obtain high quality baseline data describing the concentrations of toxic and potentially toxic trace elements and organic contaminants in the water and sediment of the San Francisco Estuary. 2. To determine seasonal and annual trends in chemical and biological water quality in the San Francisco Estuary. 3. To continue to develop a data set that can be used to determine long-term trends in the concentrations of toxic and potentially toxic trace elements and organic contaminants in the water and sediments of the San Francisco Estuary. 4. To determine whether water quality and sediment quality in the Estuary at large are in compliance with objectives established by the Basin Plan (the regulatory planning document used by the Regional Water Quality Control Board). 5. To provide a database on water and sediment quality in the Estuary which is compatible with data being developed in other ongoing studies, including wasteload allocation studies and model development, sediment quality objectives development, in-bay studies of dredged material disposal, Interagency Ecological Program (IEP) water quality studies, primary

  11. Regional contribution to variability and trends of global gross primary productivity

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min; Rafique, Rashid; Asrar, Ghassem R.; Bond-Lamberty, Ben; Ciais, Philippe; Zhao, Fang; Reyer, Christopher P. O.; Ostberg, Sebastian; Chang, Jinfeng; Ito, Akihiko; Yang, Jia; Zeng, Ning; Kalnay, Eugenia; West, Tristram; Leng, Guoyong; Francois, Louis; Munhoven, Guy; Henrot, Alexandra; Tian, Hanqin; Pan, Shufen; Nishina, Kazuya; Viovy, Nicolas; Morfopoulos, Catherine; Betts, Richard; Schaphoff, Sibyll; Steinkamp, Jörg; Hickler, Thomas

    2017-09-28

    Terrestrial gross primary productivity (GPP) is the largest component of the global carbon cycle and a key process for understanding land ecosystems dynamics. In this study, we used GPP estimates from a combination of eight global biome models participating in the Inter-Sectoral Impact-Model Intercomparison Project phase 2a (ISIMIP2a), the Moderate Resolution Spectroradiometer (MODIS) GPP product, and a data-driven product (Model Tree Ensemble, MTE) to study the spatiotemporal variability of GPP at the regional and global levels. We found the 2000-2010 total global GPP estimated from the model ensemble to be 117±13 Pg C yr-1 (mean ± 1 standard deviation), which was higher than MODIS (112 Pg C yr-1), and close to the MTE (120 Pg C yr-1). The spatial patterns of MODIS, MTE and ISIMIP2a GPP generally agree well, but their temporal trends are different, and the seasonality and inter-annual variability of GPP at the regional and global levels are not completely consistent. For the model ensemble, Tropical Latin America contributes the most to global GPP, Asian regions contribute the most to the global GPP trend, the Northern Hemisphere regions dominate the global GPP seasonal variations, and Oceania is likely the largest contributor to inter-annual variability of global GPP. However, we observed large uncertainties across the eight ISIMIP2a models, which are probably due to the differences in the formulation of underlying photosynthetic processes. The results of this study are useful in understanding the contributions of different regions to global GPP and its spatiotemporal variability, how the model- and observational-based GPP estimates differ from each other in time and space, and the relative strength of the eight models. Our results also highlight the models’ ability to capture the seasonality of GPP that are essential for understanding the inter-annual and seasonal variability of GPP as a major component of the carbon cycle.

  12. Intra- and inter-subject variability for increases in serum ketone bodies in patients with type 2 diabetes treated with the sodium glucose co-transporter 2 inhibitor canagliflozin.

    Science.gov (United States)

    Polidori, David; Iijima, Hiroaki; Goda, Maki; Maruyama, Nobuko; Inagaki, Nobuya; Crawford, Peter A

    2018-01-17

    Sodium glucose co-transporter 2 (SGLT2) inhibitors have been associated with increased serum ketone body levels in patients with type 2 diabetes mellitus (T2DM). In the present analysis we evaluated serum ketone body levels and variability in 1278 Japanese patients with T2DM treated with canagliflozin 100 or 200 mg. Similar mean increases in ketone body concentrations of ~2-fold were seen with both canagliflozin doses. The median (interquartile range) percent change from baseline was 62% (0;180) for acetoacetate and 78% (2;236) for β-hydroxybutyrate. Approximately two-thirds of the variability in each ketone measure was attributed to intra-subject variability. Intra-subject variability was higher for serum ketones than other metabolites. Patients in the lowest response tertile exhibited no increase in ketones. Those in the highest response tertile tended to be male and have higher fasting plasma glucose levels, lower insulin levels, and longer T2DM duration at baseline. Moreover, changes in serum ketones were not fully explained by changes in plasma fatty acids, suggesting downstream effects of SGLT2 inhibition on hepatic metabolism that favour ketogenesis. In summary, increases in serum ketone bodies with canagliflozin were greater and more variable than changes in other metabolic measures in Japanese patients with T2DM. © 2018 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.

  13. CTreconSIM - a simulator of reconstruction induced measurement variability

    DEFF Research Database (Denmark)

    Miles, James Edward

    2015-01-01

    VBA macro to model the effect of inter-reconstruction variability on orthopaedic measurements made from CT scans.......VBA macro to model the effect of inter-reconstruction variability on orthopaedic measurements made from CT scans....

  14. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  15. Hydrologic Variability of the Cosumnes River Floodplain

    Directory of Open Access Journals (Sweden)

    Eric Booth

    2006-09-01

    Full Text Available Natural floodplain ecosystems are adapted to highly variable hydrologic regimes, which include periodic droughts, infrequent large floods, and relatively frequent periods of inundation. To more effectively manage water resources and maintain ecosystem services provided by floodplains – and associated aquatic, riparian, and wetland habitats – requires an understanding of seasonal and inter-annual hydrologic variability of floodplains. The Cosumnes River, the largest river on the west-slope Sierra Nevada mountains without a major dam, provides a pertinent test case to develop a systematic classification of hydrologic variability. By examining the dynamics of its relatively natural flow regime, and a 98-year streamflow record (1908 – 2005, we identified 12 potential flood types. We identified four duration thresholds, defined as short (S, medium (M, long (L, and very long (V. We then intersected the flood duration division by three magnitude classes, defined as small-medium (1, large (2, and very large (3. Of the 12 possible flood types created by this classification matrix, the Cosumnes River streamflow record populated 10 such classes. To assess the robustness of our classification, we employed discriminant analysis to test class fidelity based on independent measures of flood capability, such as start date. Lastly, we used hierarchical divisive clustering to classify water years by flood type composition resulting in 8 water year types. The results of this work highlight the significant seasonal and inter-annual variability in natural flood regimes in Central Valley rivers. The construction of water impoundment and flood control structures has significantly altered all aspects of the flood pulse. Restoring floodplain ecosystem services will require re-establishing key elements of these historic flood regimes in order to achieve regional restoration goals and objectives.

  16. Lithogenic sources, composition and intra-annual variability of suspended particulate matter supplied from rivers to the Northern Galician Rias (Bay of Biscay)

    Science.gov (United States)

    Bernárdez, Patricia; Prego, Ricardo; Filgueiras, Ana Virginia; Ospina-Álvarez, Natalia; Santos-Echeandía, Juan; Álvarez-Vázquez, Miguel Angel; Caetano, Miguel

    2017-12-01

    Scarce research about small European rivers from non-human impacted areas to determine their natural background state has been undertaken. During the annual hydrological cycle of 2008-9 the patterns of particulate supply (SPM, POC, PON, Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, V, Zn) from the rivers Sor, Mera Landro, Lourido and Landoi to the Northern Galician Rias (SW Bay of Biscay) were tackled. No differences in the composition of the SPM were detected for the studied rivers regarding Al, Fe and POC but the relative percentage of particulate trace elements (PTE) discriminate the rivers. So, Cr, Co and Ni in the Lourido, and Landoi rivers, and Cu in the Mera River, are controlled by watershed minerals of Ortegal Geological Complex while for the rest rivers PTE are by granitic and Ollo de Sapo bedrock watershed. Therefore, the imprint of PTE in the parental rocks of the river basins is reflected on the coastal sediments of the Rias. The main process controlling the dynamics and variations of chemical elements in the particulate form is the river discharge. This fact exemplifies that these rivers presents a natural behavior not being highly influenced by anthropogenic activities.

  17. On the competition among aerosol number, size and composition in predicting CCN variability: a multi-annual field study in an urbanized desert.

    Science.gov (United States)

    Crosbie, E; Youn, J-S; Balch, B; Wonaschütz, A; Shingler, T; Wang, Z; Conant, W C; Betterton, E A; Sorooshian, A

    2015-02-10

    A 2-year data set of measured CCN (cloud condensation nuclei) concentrations at 0.2 % supersaturation is combined with aerosol size distribution and aerosol composition data to probe the effects of aerosol number concentrations, size distribution and composition on CCN patterns. Data were collected over a period of 2 years (2012-2014) in central Tucson, Arizona: a significant urban area surrounded by a sparsely populated desert. Average CCN concentrations are typically lowest in spring (233 cm -3 ), highest in winter (430 cm -3 ) and have a secondary peak during the North American monsoon season (July to September; 372 cm -3 ). There is significant variability outside of seasonal patterns, with extreme concentrations (1 and 99 % levels) ranging from 56 to 1945 cm -3 as measured during the winter, the season with highest variability. Modeled CCN concentrations based on fixed chemical composition achieve better closure in winter, with size and number alone able to predict 82% of the variance in CCN concentration. Changes in aerosol chemical composition are typically aligned with changes in size and aerosol number, such that hygroscopicity can be parameterized even though it is still variable. In summer, models based on fixed chemical composition explain at best only 41% (pre-monsoon) and 36% (monsoon) of the variance. This is attributed to the effects of secondary organic aerosol (SOA) production, the competition between new particle formation and condensational growth, the complex interaction of meteorology, regional and local emissions and multi-phase chemistry during the North American monsoon. Chemical composition is found to be an important factor for improving predictability in spring and on longer timescales in winter. Parameterized models typically exhibit improved predictive skill when there are strong relationships between CCN concentrations and the prevailing meteorology and dominant aerosol physicochemical processes, suggesting that similar findings could

  18. On the competition among aerosol number, size and composition in predicting CCN variability: a multi-annual field study in an urbanized desert

    Science.gov (United States)

    Crosbie, E.; Youn, J.-S.; Balch, B.; Wonaschütz, A.; Shingler, T.; Wang, Z.; Conant, W. C.; Betterton, E. A.; Sorooshian, A.

    2015-06-01

    A 2-year data set of measured CCN (cloud condensation nuclei) concentrations at 0.2 % supersaturation is combined with aerosol size distribution and aerosol composition data to probe the effects of aerosol number concentrations, size distribution and composition on CCN patterns. Data were collected over a period of 2 years (2012-2014) in central Tucson, Arizona: a significant urban area surrounded by a sparsely populated desert. Average CCN concentrations are typically lowest in spring (233 cm-3), highest in winter (430 cm-3) and have a secondary peak during the North American monsoon season (July to September; 372 cm-3). There is significant variability outside of seasonal patterns, with extreme concentrations (1 and 99 % levels) ranging from 56 to 1945 cm-3 as measured during the winter, the season with highest variability. Modeled CCN concentrations based on fixed chemical composition achieve better closure in winter, with size and number alone able to predict 82 % of the variance in CCN concentration. Changes in aerosol chemical composition are typically aligned with changes in size and aerosol number, such that hygroscopicity can be parameterized even though it is still variable. In summer, models based on fixed chemical composition explain at best only 41 % (pre-monsoon) and 36 % (monsoon) of the variance. This is attributed to the effects of secondary organic aerosol (SOA) production, the competition between new particle formation and condensational growth, the complex interaction of meteorology, regional and local emissions and multi-phase chemistry during the North American monsoon. Chemical composition is found to be an important factor for improving predictability in spring and on longer timescales in winter. Parameterized models typically exhibit improved predictive skill when there are strong relationships between CCN concentrations and the prevailing meteorology and dominant aerosol physicochemical processes, suggesting that similar findings could be

  19. Temporal and spatial distribution of endangered juvenile Lost River and shortnose suckers in relation to environmental variables in Upper Klamath Lake, Oregon: 2009 annual data summary

    Science.gov (United States)

    Bottcher, Jared L.; Burdick, Summer M.

    2010-01-01

    Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) were listed as endangered in 1988 for a variety of reasons including apparent recruitment failure. Upper Klamath Lake, Oregon, and its tributaries are considered the most critical remaining habitat for these two species. Age-0 suckers are often abundant in Upper Klamath Lake throughout the summer months, but catches decline dramatically between late August and early September each year. Similar declines of age-1 suckers between spring and late summer also occur annually. These rapid declines in catch rates and a lack of substantial recruitment into adult sucker populations in recent years suggests sucker populations experience high mortality between their first summer and first spawn. Summer age-0 sucker habitat use and distribution have been studied extensively, but many uncertainties remain about age-1 and older juvenile habitat use, distribution, and movement patterns within Upper Klamath Lake. This study was designed to examine seasonal changes in distribution of age-1 suckers in Upper Klamath Lake as they relate to depth and water quality. The results of our third annual spring and summer sampling effort are presented in this report. Catch data collected in 2009 indicate seasonal changes in age-1 and older juvenile sucker habitat use coincident with changes in water quality. Although age-1 sucker catch rates were again concentrated along the western shore in June and early July, as they were in 2007 and 2008, very few age-1 suckers were captured in Eagle Ridge Trench in 2009 - a deepwater area along the western shore extending from Howard Bay to Eagle Ridge Point. Instead, suckers in 2009 were concentrated in the relatively shallow bays along the western shore. Nevertheless, as dissolved-oxygen concentrations decreased in mid-July below sublethal thresholds around the Eagle Ridge Trench, age-1 suckers apparently moved away from the western shore, and subsequently were captured

  20. The LADM based on INTERLIS

    NARCIS (Netherlands)

    Germann, M.; Kaufmann, J.; Lemmen, C.H.J.; Van Oosterom, P.J.M.; De Zeeuw, K.

    2015-01-01

    Both the conceptual schema language INTERLIS and the land administration domain model (LADM) share the same model driven architecture (MDA) principles. In this paper we explore how INTERLIS and LADM complement each other in actual implementation of land administration system based on the LADM using

  1. Wind resource in metropolitan France: assessment methods, variability and trends

    International Nuclear Information System (INIS)

    Jourdier, Benedicte

    2015-01-01

    France has one of the largest wind potentials in Europe, yet far from being fully exploited. The wind resource and energy yield assessment is a key step before building a wind farm, aiming at predicting the future electricity production. Any over-estimation in the assessment process puts in jeopardy the project's profitability. This has been the case in the recent years, when wind farm managers have noticed that they produced less than expected. The under-production problem leads to questioning both the validity of the assessment methods and the inter-annual wind variability. This thesis tackles these two issues. In a first part are investigated the errors linked to the assessment methods, especially in two steps: the vertical extrapolation of wind measurements and the statistical modelling of wind-speed data by a Weibull distribution. The second part investigates the inter-annual to decadal variability of wind speeds, in order to understand how this variability may have contributed to the under-production and so that it is better taken into account in the future. (author) [fr

  2. Climate Variability and Yields of Major Staple Food Crops in Northern Ghana

    Science.gov (United States)

    Amikuzuno, J.

    2012-12-01

    Climate variability, the short-term fluctuations in average weather conditions, and agriculture affect each other. Climate variability affects the agroecological and growing conditions of crops and livestock, and is recently believed to be the greatest impediment to the realisation of the first Millennium Development Goal of reducing poverty and food insecurity in arid and semi-arid regions of developing countries. Conversely, agriculture is a major contributor to climate variability and change by emitting greenhouse gases and reducing the agroecology's potential for carbon sequestration. What however, is the empirical evidence of this inter-dependence of climate variability and agriculture in Sub-Sahara Africa? In this paper, we provide some insight into the long run relationship between inter-annual variations in temperature and rainfall, and annual yields of the most important staple food crops in Northern Ghana. Applying pooled panel data of rainfall, temperature and yields of the selected crops from 1976 to 2010 to cointegration and Granger causality models, there is cogent evidence of cointegration between seasonal, total rainfall and crop yields; and causality from rainfall to crop yields in the Sudano-Guinea Savannah and Guinea Savannah zones of Northern Ghana. This suggests that inter-annual yields of the crops have been influenced by the total mounts of rainfall in the planting season. Temperature variability over the study period is however stationary, and is suspected to have minimal effect if any on crop yields. Overall, the results confirm the appropriateness of our attempt in modelling long-term relationships between the climate and crop yield variables.

  3. Monitoring temporal and spatial variability in sandeel (Ammodytes hexapterus) abundance with pigeon guillemot (Cepphus columba) diets

    Science.gov (United States)

    Litzow, Michael A.; Piatt, John F.; Abookire, Alisa A.; Prichard, A.K.; Robards, Martin D.

    2000-01-01

    We evaluated pigeon guillemots (Cepphus columba) as monitors of nearshore fish abundance and community composition during 1995-1999 at Kachemak Bay, Alaska. We studied the composition of chick diets at 10 colonies and simultaneously measured fish abundance around colonies with beach seines and bottom trawls. Sandeels (Ammodytes hexapterus) formed the majority of the diet at one group of colonies. Temporal variability in sandeel abundance explained 74% of inter-annual variability in diet composition at these colonies and 93% of seasonal variability. Diets at other colonies were dominated by demersal fish. Among these colonies, 81% of the variability in the proportion of sandeels in diets was explained by spatial differences in sanded abundance. Pigeon guillemots exhibited a non-linear functional response to sandeel abundance in the area where these fish were most abundant. Temporal and spatial variability in demersal fish abundance was not consistently reflected in diets. Spatial differences in the proportion of different demersal fishes in the diet may have been driven by differences in guillemot prey preference. Prey specialization by individual pigeon guillemots was common, and may operate at the colony level. Inter-annual variability in sandeel abundance may have been tracked more accurately because the magnitude of change (11-fold) was greater than that of demersal fish (three-fold). (C) 2000 International Council for the Exploration of the Sea.

  4. Intra-annual variability of anatomical structure and δ13C values within tree rings of spruce and pine in alpine, temperate and boreal Europe

    Science.gov (United States)

    Vaganov, Eugene A.; Skomarkova, Marina V.; Knohl, Alexander; Brand, Willi A.; Roscher, Christiane

    2009-01-01

    Tree-ring width, wood density, anatomical structure and 13C/12C ratios expressed as δ13C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, δ13C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, cell-wall thickness, cell-wall area and cell-lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the δ13C between late wood and early wood. The results are interpreted in the context of the biochemistry of wood formation and its linkage to storage products. It is clear that the relations between δ13C and tree-ring width and climate are multi-factorial in seasonal climates. PMID:19653008