Science.gov

Sample records for predicting long-term creep

  1. Long-term prediction of creep strains of mineral wool slabs under constant compressive stress

    NASA Astrophysics Data System (ADS)

    Gnip, Ivan; Vaitkus, Saulius; Keršulis, Vladislovas; Vėjelis, Sigitas

    2012-02-01

    The results obtained in determining the creep strain of mineral wool slabs under compressive stress, used for insulating flat roofs and facades, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. The creep strain tests were conducted under a compressive stress of σ c =0.35 σ 10%. Interval forecasting of creep strain was made by extrapolating the creep behaviour and approximated in accordance with EN 1606 by a power equation and reduced to a linear form using logarithms. This was performed for a lead time of 10 years. The extension of the range of the confidence interval due to discount of the prediction data, i.e. a decrease in their informativity was allowed for by an additional coefficient. Analysis of the experimental data obtained from the tests having 65 and 122 days duration showed that the prediction of creep strains for 10 years can be made based on data obtained in experiments with durations shorter than the 122 days as specified by EN 13162. Interval prediction of creep strains (with a confidence probability of 90%) was based on using the mean square deviation of the actual direct observations of creep strains in logarithmic form to have the linear trend in a retrospective area.

  2. Advanced Procedures for Long-Term Creep Data Prediction for 2.25 Chromium Steels

    NASA Astrophysics Data System (ADS)

    Whittaker, Mark T.; Wilshire, Brian

    2013-01-01

    A critical review of recent creep studies concluded that traditional approaches such as steady-state behavior, power law equations, and the view that diffusional creep mechanisms are dominant at low stresses should be seriously reconsidered. Specifically, creep strain rate against time curves show that a decaying primary rate leads into an accelerating tertiary stage, giving a minimum rather than a secondary period. Conventional steady-state mechanisms should therefore be abandoned in favor of an understanding of the processes governing strain accumulation and the damage phenomena causing tertiary creep and fracture. Similarly, creep always takes place by dislocation processes, with no change to diffusional creep mechanisms with decreasing stress, negating the concept of deformation mechanism maps. Alternative descriptions are then provided by normalizing the applied stress through the ultimate tensile stress and yield stress at the creep temperature. In this way, the resulting Wilshire equations allow accurate prediction of 100,00 hours of creep data using only property values from tests lasting 5000 hours for a series of 2.25 chromium steels, namely grades 22, 23, and 24.

  3. Estimation of long-term creep behavior of salt

    SciTech Connect

    Chun, R.C.

    1980-08-01

    A computer routine for both primary and secondary creep laws has been developed using a modified strain hardening law. The computations reveal that results from Heard's steady-state creep law and Lomenick and Bradshaw's primary creep law can differ from each other by a factor of thirty after about 6 hours of creep deformation, but the difference diminishes as time becomes large. The belief that these two creep laws may yield long-term results that are orders of magnitude apart is shown to be unfounded.

  4. Effect of interconnect creep on long-term performance of SOFC of one cell stacks

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2008-02-01

    Creep deformation becomes relevant for a material when the operating temperature is near or exceeds half of its melting temperature (in degrees of Kelvin). The operating temperatures for most of the solid oxide fuel cells (SOFC) under development in the SECA program are around 1073oK. High temperature ferritic alloys are potential candidates as interconnect (IC) materials and spacers due to their low cost and CTE compatibility with other SOFC components. Since the melting temperature of most stainless steel is around 1800oK, possible creep deformation of IC under the typical cell operating temperature should not be neglected. In this paper, the effects of interconnect creep behavior on stack geometry change and stress redistribution of different cell components are predicted and summarized. The goal of the study is to investigate the performance of the fuel cell stack by obtaining the fuel and air channel geometry changes due to creep of the ferritic stainless steel interconnect, therefore indicating possible SOFC performance change under long term operations. IC creep models were incorporated into SOFC-MP and Mentat FC, and finite element analyses were performed to quantify the deformed configuration of the SOFC stack under the long term steady state operating temperature. It is found that creep behavior of the ferritic stainless steel IC contributes to narrowing of both the fuel and the air flow channels. In addition, stress re-distribution of the cell components suggests the need for a compliant sealing material that also relaxes at operating temperature.

  5. Climate Predictability and Long Term Memory

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Blender, R.; Fraedrich, K.; Liu, Z.

    2010-09-01

    The benefit of climate Long Term Memory (LTM) for long term prediction is assessed using data from a millennium control simulation with the atmosphere ocean general circulation model ECHAM5/MPIOM. The forecast skills are evaluated for surface temperature time series at individual grid points. LTM is characterised by the Hurst exponent in the power-law scaling of the fluctuation function which is determined by detrended fluctuation analysis (DFA). LTM with a Hurst exponent close to 0.9 occurs mainly in high latitude oceans, which are also characterized by high potential predictability. Climate predictability is diagnosed in terms of potentially predictable variance fractions. Explicit prediction experiments for various time steps are conducted on a grid point basis using an auto-correlation (AR1) predictor: in regions with LTM, prediction skills are beyond that expected from red noise persistence; exceptions occur in some areas in the southern oceans and over the northern hemisphere continents. Extending the predictability analysis to the fully forced simulation shows large improvement in prediction skills.

  6. Prediction of long-term failure in Kevlar 49 composites

    SciTech Connect

    Gerstle, F.P. Jr.

    1982-01-01

    Creep rupture data in Kevlar 49 epoxy usually exhibit considerable scatter: the coefficient of variation (CV) about the mean failure time at a given stress exceeds 100%. Quasi-static strength data, in contrast, shows little scatter: <4% CV for pressure vessels and <10% for impregnated strands. In this paper analysis of existing creep rupture data on Kevlar epoxy vessels at four storage pressures has produced an interesting and useful result. It was found that a significant portion of the scatter in failure times for pressure vessels is due to spool-to-spool variation in the eight spools of Kevlar fibers used to wind the vessels. The order rank of mean times to failure was consistent over a pressure range from 3400 to 4300 psi, 68 to 86% of short term burst. Also, the coefficient of variation about the mean failure time for each spool was less than that for the total sample. The statistical inference that the sample is nonhomogeneous was supported by a nonparametric check using the Kruskal-Wallis test, and by a parametric analysis of variance. The order rank found in long-term tests did not unequivocally agree with static strength ranks; several spool sets were distinctly high or low. The implication is that, while static strengths are not valid predictors of long-term behavior, short term creep rupture tests at high stress definitely are. The material difference which causes the spool-to-spool variations has not yet been identified for all eight spools. However, it appears that Kevlar behavior at lower pressures may be predicted through the use of curves fitted to the data for each spool. A power law relating failure time to pressure, t = t/sub 0/(p/p/sub 0/)/sup m/, was found to fit the data reasonably well. The implication is that, both in composite vessel design and in creep rupture experiments, the pressure (or stress) level be carefully controlled.

  7. Intermediate- and long-term earthquake prediction.

    PubMed Central

    Sykes, L R

    1996-01-01

    Progress in long- and intermediate-term earthquake prediction is reviewed emphasizing results from California. Earthquake prediction as a scientific discipline is still in its infancy. Probabilistic estimates that segments of several faults in California will be the sites of large shocks in the next 30 years are now generally accepted and widely used. Several examples are presented of changes in rates of moderate-size earthquakes and seismic moment release on time scales of a few to 30 years that occurred prior to large shocks. A distinction is made between large earthquakes that rupture the entire downdip width of the outer brittle part of the earth's crust and small shocks that do not. Large events occur quasi-periodically in time along a fault segment and happen much more often than predicted from the rates of small shocks along that segment. I am moderately optimistic about improving predictions of large events for time scales of a few to 30 years although little work of that type is currently underway in the United States. Precursory effects, like the changes in stress they reflect, should be examined from a tensorial rather than a scalar perspective. A broad pattern of increased numbers of moderate-size shocks in southern California since 1986 resembles the pattern in the 25 years before the great 1906 earthquake. Since it may be a long-term precursor to a great event on the southern San Andreas fault, that area deserves detailed intensified study. Images Fig. 1 PMID:11607658

  8. Intermediate- and long-term earthquake prediction.

    PubMed

    Sykes, L R

    1996-04-30

    Progress in long- and intermediate-term earthquake prediction is reviewed emphasizing results from California. Earthquake prediction as a scientific discipline is still in its infancy. Probabilistic estimates that segments of several faults in California will be the sites of large shocks in the next 30 years are now generally accepted and widely used. Several examples are presented of changes in rates of moderate-size earthquakes and seismic moment release on time scales of a few to 30 years that occurred prior to large shocks. A distinction is made between large earthquakes that rupture the entire downdip width of the outer brittle part of the earth's crust and small shocks that do not. Large events occur quasi-periodically in time along a fault segment and happen much more often than predicted from the rates of small shocks along that segment. I am moderately optimistic about improving predictions of large events for time scales of a few to 30 years although little work of that type is currently underway in the United States. Precursory effects, like the changes in stress they reflect, should be examined from a tensorial rather than a scalar perspective. A broad pattern of increased numbers of moderate-size shocks in southern California since 1986 resembles the pattern in the 25 years before the great 1906 earthquake. Since it may be a long-term precursor to a great event on the southern San Andreas fault, that area deserves detailed intensified study.

  9. The prediction of long term viscoelastic properties of fiber reinforced plastics

    NASA Technical Reports Server (NTRS)

    Brinson, H. F.; Dillard, D. A.

    1982-01-01

    A method for the experimental and analytical accelerated characterization of long term viscoelastic properties is presented. The time-temperature-stress superposition principle (TTSSP) is shown to serve as the basis for determining long term compliance data from short term creep test results. Nonlinear viscoelastic theories are discussed to provide the framework for the mathematically modeling of such a process. A time dependent Tsai-Hill-Zhurkov failure theory is used to determine long term failure properties from short term data. Compliance and failure data are incorporated in an incremental lamination theory to make long term laminate predictions. Comparisons are made between theory and experiment.

  10. Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

    SciTech Connect

    Shen, Chen

    2015-01-01

    We report here a constitutive model for predicting long-term creep strain evolution in’ strengthened Ni-base superalloys. Dislocation climb-bypassing’, typical in intermediate’ volume fraction (~20%) alloys, is considered as the primary deformation mechanism. Dislocation shearing’ to anti-phase boundary (APB) faults and diffusional creep are also considered for high-stress and high-temperature low-stress conditions, respectively. Additional damage mechanism is taken into account for rapid increase in tertiary creep strain. The model has been applied to Alloy 282, and calibrated in a temperature range of 1375-1450°F, and stress range of 15-45ksi. The model parameters and a MATLAB code are provided. This report is prepared by Monica Soare and Chen Shen at GE Global Research. Technical discussions with Dr. Vito Cedro are greatly appreciated. This work was supported by DOE program DE-FE0005859

  11. Revised long-term creep rates on the Hayward Fault, Alameda and Contra Costa Counties, California

    USGS Publications Warehouse

    Lienkaemper, James J.; Galehouse, Jon S.

    1997-01-01

    Although the Hayward fault is a source of major earthquakes, it also creeps or slips aseismically, and has done so steadily for several decades (certainly since 1921 and probably since 1869). Most of the fault creeps between 3 and 6 mm/yr, except for a 4- to 6-km-long segment near its south end that creeps at about 9 mm/yr. We present results of our recent surveys to recover angles and deflection lines established across the fault in the 1960s and 1970s, but unmonitored since. We have added data from more offset cultural features to the long-term creep rate data set and made substantial improvements to the analytical method used to compute offsets. The revised creep rate values improve our knowledge of spatial and temporal variation along the fault. The more accurate revised data has reduced the estimate of the average creep rate along most of the fault from 5.1 mm/yr to 4.6 mm/yr. Creep rates in the 9 mm/yr section near the south end have remained the same.

  12. Bone creep and short and long term subsidence after cemented stem total hip arthroplasty (THA).

    PubMed

    Norman, T L; Shultz, T; Noble, G; Gruen, T A; Blaha, J D

    2013-03-15

    Stem-cement and cement-bone interfacial failures as well as cement fractures have been noted in cemented total hip arthroplasty (THA) as the cause of aseptic loosening. Attempts to reduce the risk of femoral component loosening include improving the stem-cement interface by various coatings, using a textured or porous coated stem surfaces or by using a tapered stem having a highly-polished surface. The latter approach, often referred to as "force-closed" femoral stem design, would theoretically result in stem stabilization subsequent to debonding and 'taper-lock'. Previous work using three-dimensional finite element analysis has shown a state of stress at the stem-cement interface indicative of 'taper-lock' for the debonded stem and indicated that stem-cement interface friction and bone cement creep played a significant role in the magnitudes of stresses and subsidence of the stem. However, the previous analysis did not include the viscoelastic properties of bone, which has been hypothesized to permit additional expansion of the bone canal and allow additional stem subsidence (Lu and McKellop, 1997). The goal of this study was to investigate the effect of bone viscoelastic behavior on stem subsidence using a 3D finite element analysis. It was hypothesized that the viscoelastic behavior of bone in the hoop direction would allow expansion of the bone reducing the constraint on bone over time and permit additional stem subsidence, which may account for the discrepancies between predicted and clinical subsidence measurements. Analyses were conducted using physiological loads, 'average peak loads' and 'high peak loads' for 'normal patient' and 'active patient' (Bergmann et al., 2010) from which short and long term subsidence was predicted. Results indicated that bone creep does contribute to higher stem subsidence initially and after 10 years of simulated loading. However, it was concluded that the "constraint" upon the cement mantle is not mitigated enough to result in

  13. Effect of Creep of Ferritic Interconnect on Long-Term Performance of Solid Oxide Fuel Cell Stacks

    SciTech Connect

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2010-08-01

    High-temperature ferritic alloys are potential candidates as interconnect (IC) materials and spacers due to their low cost and coefficient of thermal expansion (CTE) compatibility with other components for most of the solid oxide fuel cells (SOFCs) . However, creep deformation becomes relevant for a material when the operating temperature exceeds or even is less than half of its melting temperature (in degrees of Kelvin). The operating temperatures for most of the SOFCs under development are around 1,073 K. With around 1,800 K of the melting temperature for most stainless steel, possible creep deformation of ferritic IC under the typical cell operating temperature should not be neglected. In this paper, the effects of IC creep behavior on stack geometry change and the stress redistribution of different cell components are predicted and summarized. The goal of the study is to investigate the performance of the fuel cell stack by obtaining the changes in fuel- and air-channel geometry due to creep of the ferritic stainless steel IC, therefore indicating possible changes in SOFC performance under long-term operations. The ferritic IC creep model was incorporated into software SOFC-MP and Mentat-FC, and finite element analyses were performed to quantify the deformed configuration of the SOFC stack under the long-term steady-state operating temperature. It was found that the creep behavior of the ferritic stainless steel IC contributes to narrowing of both the fuel- and the air-flow channels. In addition, stress re-distribution of the cell components suggests the need for a compliant sealing material that also relaxes at operating temperature.

  14. Long-term predictions using natural analogues

    SciTech Connect

    Ewing, R.C.

    1995-09-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10{sup 3}-10{sup 5} years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., {open_quotes}natural analogues{close_quotes}) provide perhaps the only means of partial {open_quotes}validation,{close_quotes} as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10{sup 3}-10{sup 8} years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the {open_quotes}validation{close_quotes} of performance assessments.

  15. Prediction of Long Term Degradation of Insulating Materials

    DTIC Science & Technology

    2015-05-01

    Physical changes .......................................................................................................... 20 4.2 Thermal performance ...to address the enduring challenge of developing and evaluating the long-term performance of a thermal insula- tion for shelter systems that provides...properties of selected insulation ma- terials based on the differences in thermal conductivity and R-values. 3. Predict the long-term performance of selected

  16. Long-term monitoring of creep rate along the Hayward fault and evidence for a lasting creep response to 1989 Loma Prieta earthquake

    USGS Publications Warehouse

    Lienkaemper, J.J.; Galehouse, J.S.; Simpson, R.W.

    2001-01-01

    We present results from over 30 yr of precise surveys of creep along the Hayward fault. Along most of the fault, spatial variability in long-term creep rates is well determined by these data and can help constrain 3D-models of the depth of the creeping zone. However, creep at the south end of the fault stopped completely for more than 6 years after the M7 1989 Loma Prieta Earthquake (LPEQ), perhaps delayed by stress drop imposed by this event. With a decade of detailed data before LPEQ and a decade after it, we report that creep response to that event does indeed indicate the expected deficit in creep.

  17. Effects of physical aging on long-term creep of polymers and polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Brinson, L. Catherine; Gates, Thomas S.

    1994-01-01

    For many polymeric materials in use below the glass transition temperature, the long term viscoelastic behavior is greatly affected by physical aging. To use polymer matrix composites as critical structural components in existing and novel technological applications, this long term behavior of the material system must be understood. Towards that end, this study applied the concepts governing the mechanics of physical aging in a consistent manner to the study of laminated composite systems. Even in fiber-dominated lay-ups the effects of physical aging are found to be important in the long-term behavior of the composite. The basic concepts describing physical aging of polymers are discussed. Several aspects of physical aging which have not been previously documented are also explored in this study, namely the effects of aging into equilibrium and a relationship to the time-temperature shift factor. The physical aging theory is then extended to develop the long-term compliance/modulus of a single lamina with varying fiber orientation. The latter is then built into classical lamination theory to predict long-time response of general oriented lamina and laminates. It is illustrated that the long term response can be counterintuitive, stressing the need for consistent modeling efforts to make long term predictions of laminates to be used in structural situations.

  18. Preliminary Development of a Unified Viscoplastic Constitutive Model for Alloy 617 with Special Reference to Long Term Creep Behavior

    SciTech Connect

    Sham, Sam; Walker, Kevin P.

    2008-01-01

    The expected service life of the Next Generation Nuclear Plant is 60 years. Structural analyses of the Intermediate Heat Exchanger (IHX) will require the development of unified viscoplastic constitutive models that address the material behavior of Alloy 617, a construction material of choice, over a wide range of strain rates. Many unified constitutive models employ a yield stress state variable which is used to account for cyclic hardening and softening of the material. For low stress values below the yield stress state variable these constitutive models predict that no inelastic deformation takes place which is contrary to experimental results. The ability to model creep deformation at low stresses for the IHX application is very important as the IHX operational stresses are restricted to very small values due to the low creep strengths at elevated temperatures and long design lifetime. This paper presents some preliminary work in modeling the unified viscoplastic constitutive behavior of Alloy 617 which accounts for the long term, low stress, creep behavior and the hysteretic behavior of the material at elevated temperatures. The preliminary model is presented in one-dimensional form for ease of understanding, but the intent of the present work is to produce a three-dimensional model suitable for inclusion in the user subroutines UMAT and USERPL of the ABAQUS and ANSYS nonlinear finite element codes. Further experiments and constitutive modeling efforts are planned to model the material behavior of Alloy 617 in more detail.

  19. Is Current Hydrogeologic Research Addressing Long-TermPredictions?

    SciTech Connect

    Tsang, Chin-Fu

    2004-09-10

    Hydrogeology is a field closely related to the needs of society. Many problems of current national and local interest require predictions of hydrogeological system behavior, and, in a number of important cases, the period of prediction is tens to hundreds of thousands of years. It is argued that the demand for such long-term hydrogeological predictions casts a new light on the future needs of hydrogeological research. Key scientific issues are no longer concerned only with simple processes or narrowly focused modeling or testing methods, but also with assessment of prediction uncertainties and confidence, couplings among multiple physico-chemical processes occurring simultaneously at a site, and the interplay between site characterization and predictive modeling. These considerations also have significant implications for hydrogeological education. With this view, it is asserted that hydrogeological directions and education need to be reexamined and possibly refocused to address specific needs for long-term predictions.

  20. Long-term performance of ceramic matrix composites at elevated temperatures: Modelling of creep and creep rupture

    SciTech Connect

    Curtin, W.A.; Fabeny, B.; Ibnabdeljalil, M.; Iyengar, N.; Reifsnider, K.L.

    1996-07-31

    The models developed, contain explicit dependences on constituent material properties and their changes with time, so that composite performance can be predicted. Three critical processes in ceramic composites at elevated temperatures have been modeled: (1) creep deformation of composite vs stress and time-dependent creep of fibers and matrix, and failure of these components; (2) creep deformation of ``interface`` around broken fibers; and (3) lifetime of the composite under conditions of fiber strength loss over time at temperature. In (1), general evolution formulas are derived for relaxation time of matrix stresses and steady-state creep rate of composite; the model is tested against recent data on Ti-MMCs. Calculations on a composite of Hi-Nicalon fibers in a melt-infiltrated SiC matrix are presented. In (2), numerical simulations of composite failure were made to map out time-to-failure vs applied load for several sets of material parameters. In (3), simple approximate relations are obtained between fiber life and composite life that should be useful for fiber developers and testers. Strength degradation data on Hi-Nicalon fibers is used to assess composite lifetime vs fiber lifetime for Hi-Nicalon fiber composites.

  1. Long-term deflections of reinforced concrete elements: accuracy analysis of predictions by different methods

    NASA Astrophysics Data System (ADS)

    Gribniak, Viktor; Bacinskas, Darius; Kacianauskas, Rimantas; Kaklauskas, Gintaris; Torres, Lluis

    2013-08-01

    Long-term deflection response of reinforced concrete flexural members is influenced by the interaction of complex physical phenomena, such as concrete creep, shrinkage and cracking, which makes their prediction difficult. A number of approaches are proposed by design codes with different degrees of simplification and accuracy. This paper statistically investigates accuracy of long-term deflection predictions made by some of the most widely used design codes ( Eurocode 2, ACI 318, ACI 435, and the new Russian code SP 52-101) and a numerical technique proposed by the authors. The accuracy is analyzed using test data of 322 reinforced concrete members from 27 test programs reported in the literature. The predictions of each technique are discussed, and a comparative analysis is made showing the influence of different parameters, such as sustained loading duration, compressive strength of concrete, loading intensity and reinforcement ratio, on the prediction accuracy.

  2. Evaluation of hoop creep behaviors in long-term dry storage condition of pre-hydrided and high burn-up nuclear fuel cladding

    SciTech Connect

    Kim, Sun-Ki; Bang, J.G.; Kim, D.H.; Yang, Y.S.

    2007-07-01

    Related to the degradation of the mechanical properties of Zr-based nuclear fuel cladding tubes under long term dry storage condition, the mechanical tests which can simulate the degradation of the mechanical properties properly are needed. Especially, the degradation of the mechanical properties by creep mechanism seems to be dominant under long term dry storage condition. Accordingly, in this paper, ring creep tests were performed in order to evaluate the creep behaviors of high burn-up fuel cladding under a hoop loading condition in a hot cell. The tests are performed with Zircaloy-4 fuel cladding whose burn-up is approximately {approx}60,000 MWd/tU in the temperature range from 350 deg. to 550 deg.. The tests are also performed with pre-hydrided Zircaloy-4 and ZIRLO up to 1,000 ppm. First of all, the hoop loading grip for the ring creep test was designed in order that a constant curvature of the specimen was maintained during the creep deformation, and the graphite lubricant was used to minimize the friction between the outer surface of the die insert and the inner surface of the ring specimen. The specimen for the ring creep test was designed to limit the deformation within the gauge section and to maximize the uniformity of the strain distribution. It was confirmed that the mechanical properties under a hoop loading condition can be correctly evaluated by using this test technique. In this paper, secondary creep rate with increasing hydrogen content are drawn, and then kinetic data such as pre-exponential factor and activation energy for creep process are also drawn. In addition, creep life are predicted by obtaining LMP (Larson-Miller parameter) correlation in the function of hydrogen content and applied stress to yield stress ratio. (authors)

  3. Effects of long-term thermal aging on the tensile and creep properties of commercially heat-treated alloy 718

    SciTech Connect

    Booker, M.K.

    1984-01-01

    Alloy 718 is a structure material widely used in elevated-temperature applications. In particular, it was extensively used in the design of the upper internal system and control rod drive line of the proposed Clinch River Breeder Reactor. Its popularity is due to several excellent behavioral features, including high creep and creep-rupture strength, good oxidation resistance, and exceptional high-cycle fatigue strength. However, alloy 718 is extremely complex, and its microstructure can be significantly modified by thermal treatment. The stability of the alloy in long-term elevated-temperature service is therefore a substantial concern in any such application. This report presents tensile and creep data obtained on three heats of alloy 718 after thermal aging for up to 27,000 h from 593 to 76{degree}C. Implications of these results in terms of long-term stability of the alloy are discussed. 5 refs., 13 figs., 6 tabs.

  4. Long-term time series prediction using OP-ELM.

    PubMed

    Grigorievskiy, Alexander; Miche, Yoan; Ventelä, Anne-Mari; Séverin, Eric; Lendasse, Amaury

    2014-03-01

    In this paper, an Optimally Pruned Extreme Learning Machine (OP-ELM) is applied to the problem of long-term time series prediction. Three known strategies for the long-term time series prediction i.e. Recursive, Direct and DirRec are considered in combination with OP-ELM and compared with a baseline linear least squares model and Least-Squares Support Vector Machines (LS-SVM). Among these three strategies DirRec is the most time consuming and its usage with nonlinear models like LS-SVM, where several hyperparameters need to be adjusted, leads to relatively heavy computations. It is shown that OP-ELM, being also a nonlinear model, allows reasonable computational time for the DirRec strategy. In all our experiments, except one, OP-ELM with DirRec strategy outperforms the linear model with any strategy. In contrast to the proposed algorithm, LS-SVM behaves unstably without variable selection. It is also shown that there is no superior strategy for OP-ELM: any of three can be the best. In addition, the prediction accuracy of an ensemble of OP-ELM is studied and it is shown that averaging predictions of the ensemble can improve the accuracy (Mean Square Error) dramatically.

  5. Long-term weather predictability: Ural case study

    NASA Astrophysics Data System (ADS)

    Kubyshen, Alexander; Shopin, Sergey

    2016-04-01

    The accuracy of the state-of-the-art long-term meteorological forecast (at the seasonal level) is still low. Here it is presented approach (RAMES method) realizing different forecasting methodology. It provides prediction horizon of up to 19-22 years under equal probabilities of determination of parameters in every analyzed period [1]. Basic statements of the method are the following. 1. Long-term forecast on the basis of numerical modeling of the global meteorological process is principally impossible. Extension of long-term prediction horizon could be obtained only by the revealing and using a periodicity of meteorological situations at one point of observation. 2. Conventional calendar is unsuitable for generalization of meteorological data and revealing of cyclicity of meteorological processes. RAMES method uses natural time intervals: one day, synodic month and one year. It was developed a set of special calendars using these natural periods and the Metonic cycle. 3. Long-term time series of meteorological data is not a uniform universal set, it is a sequence of 28 universal sets appropriately superseding each other in time. The specifics of the method are: 1. Usage of the original research toolkit consisting of - a set of calendars based on the Metonic cycle; - a set of charts (coordinate systems) for the construction of sequence diagrams (of daily variability of a meteorological parameter during the analyzed year; of daily variability of a meteorological parameter using long-term dynamical time series of periods-analogues; of monthly and yearly variability of accumulated value of meteorological parameter). 2. Identification and usage of new virtual meteorological objects having several degrees of generalization appropriately located in the used coordinate systems. 3. All calculations are integrated into the single technological scheme providing comparison and mutual verification of calculation results. During the prolonged testing in the Ural region, it was

  6. Long-term treatment with tetrahydrobiopterin in phenylketonuria: treatment strategies and prediction of long-term responders.

    PubMed

    Hennermann, Julia B; Roloff, Sylvia; Gebauer, Christine; Vetter, Barbara; von Arnim-Baas, Annabel; Mönch, Eberhard

    2012-11-01

    Tetrahydrobiopterin (BH4) responsive phenylketonuria has been described more than 10 years ago. However, criteria for the identification of long-term BH4 responsive patients are not yet established. 116 patients with phenylketonuria, aged 4-18 years, were screened for potential long-term BH4 responsiveness by at least two of the following criteria: positive neonatal BH4 loading test, putative BH4 responsive genotype, and/or milder phenotype. Patients had to be on permanent dietary treatment. 23 patients fulfilled these criteria and were tested for long-term BH4 responsiveness: 18/23 were long-term BH4 responsive, 5/23 were not. On long-term BH4 treatment over a period of 48 ± 27 months in a dose of 14.9 ± 3.3mg/kg/day phenylalanine tolerance was increased from 452 ± 201 mg/day to 1593 ± 647 mg/day, corresponding to a mean increase of 1141 ± 528 mg/day. Dietary phenylalanine intake was increased stepwise according to a clear defined protocol. In 8/18 patients, diet was completely liberalized; 10/18 patients still received phenylalanine-free amino acid formula with 0.63 ± 0.23 g/kg/day. The most predictive value for long-term BH4 responsiveness was the combination of pretreatment phenylalanine of < 1200 μmol/L, pretreatment phenylalanine/tyrosine ratio of <15, phenylalanine/tyrosine ratio of <15 on treatment, phenylalanine tolerance of >20mg/kg/day at age 3 years, positive neonatal BH4 loading, and at least one putative BH4 responsive mutation (p = 0.00024). Our data show that long-term BH4 responsiveness may be predicted already during neonatal period by determining maximum pretreatment phenylalanine and phenylalanine/tyrosine concentrations, neonatal BH4 loading and PAH genotype. A clear defined protocol is necessary to install long-term BH4 treatment.

  7. Prediction of long-term aging of cellular plastics

    SciTech Connect

    Fan, Y.; Kokko, E.

    1995-09-01

    Chlorofluorocarbon(CFC)-based cellular plastics are facing the challenge of environmental protection. The cellular plastic industry has been looking for new blowing agents as alternatives for CFCs since the Montreal Protocol was signed in 1987. The prediction of long-term thermal performance of newly developed cellular plastics thus becomes apparent. In this paper, the model ACP aging of cellular plastic is introduced. This model was originally developed for evaluating the thermal performance of carbon dioxide, CFC-11, CFC-12, CFC-22, n-Pentane, neo-Pentane and cyclo-Pentane. In comparison with short-term measurements, the ACP program now is able to predict the aging performance of cellular plastics is to combine the short-term measurements and model simulation. 21 refs., 5 figs., 4 tabs.

  8. Neural systems predicting long-term outcome in dyslexia.

    PubMed

    Hoeft, Fumiko; McCandliss, Bruce D; Black, Jessica M; Gantman, Alexander; Zakerani, Nahal; Hulme, Charles; Lyytinen, Heikki; Whitfield-Gabrieli, Susan; Glover, Gary H; Reiss, Allan L; Gabrieli, John D E

    2011-01-04

    Individuals with developmental dyslexia vary in their ability to improve reading skills, but the brain basis for improvement remains largely unknown. We performed a prospective, longitudinal study over 2.5 y in children with dyslexia (n = 25) or without dyslexia (n = 20) to discover whether initial behavioral or brain measures, including functional MRI (fMRI) and diffusion tensor imaging (DTI), can predict future long-term reading gains in dyslexia. No behavioral measure, including widely used and standardized reading and language tests, reliably predicted future reading gains in dyslexia. Greater right prefrontal activation during a reading task that demanded phonological awareness and right superior longitudinal fasciculus (including arcuate fasciculus) white-matter organization significantly predicted future reading gains in dyslexia. Multivariate pattern analysis (MVPA) of these two brain measures, using linear support vector machine (SVM) and cross-validation, predicted significantly above chance (72% accuracy) which particular child would or would not improve reading skills (behavioral measures were at chance). MVPA of whole-brain activation pattern during phonological processing predicted which children with dyslexia would improve reading skills 2.5 y later with >90% accuracy. These findings identify right prefrontal brain mechanisms that may be critical for reading improvement in dyslexia and that may differ from typical reading development. Brain measures that predict future behavioral outcomes (neuroprognosis) may be more accurate, in some cases, than available behavioral measures.

  9. Long-Term Creep of a Thin-Walled Inconel 718 Stirling Power-Convertor Heater Head Assessed

    NASA Technical Reports Server (NTRS)

    Bowman, Randy R.

    2002-01-01

    The Department of Energy and NASA have identified Stirling power convertors as candidate power supply systems for long-duration, deep-space science missions. A key element for qualifying the flight hardware is a long-term durability assessment for critical hot section components of the power convertor. One such critical component is the power convertor heater head. The heater head is a high-temperature pressure vessel that transfers heat to the working gas medium of the convertor, which is typically helium. An efficient heater head design is the result of balancing the divergent requirements of thin walls for increased heat transfer versus thick walls to lower the wall stresses and thus improve creep resistance and durability. In the current design, the heater head is fabricated from the Ni-base superalloy Inconel 718 (IN 718, Inco Alloys International, Inc., Huntington, WV). Although IN 718 is a mature alloy system (patented in 1962), there is little long-term (>50,000-hr) creep data available for thin-specimen geometries. Since thin-section properties tend to be inferior to thicker samples, it is necessary to generate creep data using specimens with the same geometry as the actual flight hardware. Therefore, one facet of the overall durability assessment program involves generating relatively short-term creep data using thin specimens at the design temperature of 649 C (1200 F).

  10. Long Term Mean Local Time of the Ascending Node Prediction

    NASA Technical Reports Server (NTRS)

    McKinley, David P.

    2007-01-01

    Significant error has been observed in the long term prediction of the Mean Local Time of the Ascending Node on the Aqua spacecraft. This error of approximately 90 seconds over a two year prediction is a complication in planning and timing of maneuvers for all members of the Earth Observing System Afternoon Constellation, which use Aqua's MLTAN as the reference for their inclination maneuvers. It was determined that the source of the prediction error was the lack of a solid Earth tide model in the operational force models. The Love Model of the solid Earth tide potential was used to derive analytic corrections to the inclination and right ascension of the ascending node of Aqua's Sun-synchronous orbit. Additionally, it was determined that the resonance between the Sun and orbit plane of the Sun-synchronous orbit is the primary driver of this error. The analytic corrections have been added to the operational force models for the Aqua spacecraft reducing the two-year 90-second error to less than 7 seconds.

  11. Long-term predictions of minewater geothermal systems heat resources

    NASA Astrophysics Data System (ADS)

    Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

    2014-05-01

    Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both

  12. The Greenville Fault: preliminary estimates of its long-term creep rate and seismic potential

    USGS Publications Warehouse

    Lienkaemper, James J.; Barry, Robert G.; Smith, Forrest E.; Mello, Joseph D.; McFarland, Forrest S.

    2013-01-01

    Once assumed locked, we show that the northern third of the Greenville fault (GF) creeps at 2 mm/yr, based on 47 yr of trilateration net data. This northern GF creep rate equals its 11-ka slip rate, suggesting a low strain accumulation rate. In 1980, the GF, easternmost strand of the San Andreas fault system east of San Francisco Bay, produced a Mw5.8 earthquake with a 6-km surface rupture and dextral slip growing to ≥2 cm on cracks over a few weeks. Trilateration shows a 10-cm post-1980 transient slip ending in 1984. Analysis of 2000-2012 crustal velocities on continuous global positioning system stations, allows creep rates of ~2 mm/yr on the northern GF, 0-1 mm/yr on the central GF, and ~0 mm/yr on its southern third. Modeled depth ranges of creep along the GF allow 5-25% aseismic release. Greater locking in the southern two thirds of the GF is consistent with paleoseismic evidence there for large late Holocene ruptures. Because the GF lacks large (>1 km) discontinuities likely to arrest higher (~1 m) slip ruptures, we expect full-length (54-km) ruptures to occur that include the northern creeping zone. We estimate sufficient strain accumulation on the entire GF to produce Mw6.9 earthquakes with a mean recurrence of ~575 yr. While the creeping 16-km northern part has the potential to produce a Mw6.2 event in 240 yr, it may rupture in both moderate (1980) and large events. These two-dimensional-model estimates of creep rate along the southern GF need verification with small aperture surveys.

  13. Long-term Observation of Soil Creep Activity around a Landslide Scar

    EPA Science Inventory

    Rate of sediment infilling into landslide scars by soil creep is needed to estimate the timing of subsequent landslide activity at a particular site. However, knowledge about the spatial distribution of its activity around the landslide scar is scarce. Additionally, there are few...

  14. Long-term predictive capability of erosion models

    NASA Technical Reports Server (NTRS)

    Veerabhadra, P.; Buckley, D. H.

    1983-01-01

    A brief overview of long-term cavitation and liquid impingement erosion and modeling methods proposed by different investigators, including the curve-fit approach is presented. A table was prepared to highlight the number of variables necessary for each model in order to compute the erosion-versus-time curves. A power law relation based on the average erosion rate is suggested which may solve several modeling problems.

  15. Predicting long-term sickness absence from sleep and fatigue.

    PubMed

    Akerstedt, Torbjorn; Kecklund, Goran; Alfredsson, Lars; Selen, Jan

    2007-12-01

    Disturbed or shortened sleep is prospectively related to disease. One might also expect that sickness absence would be another consequence but very little data seem to exist. The present study used 8300 individuals in a national sample to obtain information on reports of disturbed sleep and fatigue one [corrected] year and merged this with data on long-term sickness absence two [corrected] years later. A logistic regression analysis was applied to the data with adjustments for demographic and work environment variables. The results showed that individuals without registered sickness absence at the start had a higher probability of entering a period of long-term (>/=90 days, odds ratio [OR] = 1.24 with 95% Confidence Interval [CI] = 1.09[corrected]-2.18[corrected]) sickness absence two [corrected] years later if they reported disturbed sleep at the start. The value [corrected] for fatigue was OR = 1.69[corrected] (CI = 1.23[corrected]-2.33[corrected]). When fatigue or disturbed sleep was separately excluded the OR increased to OR = 1.90[corrected] and OR = 1.86[corrected], respectively. Intermediate sickness absence (14-89 days) showed similar but slightly weaker results. The results indicate that disturbed sleep and fatigue are predictors of long-term absence and it is suggested that impaired sleep may be part of a chain of causation, considering its effects on fatigue.

  16. Long term prediction and the SSC (Superconducting Super Collider)

    SciTech Connect

    Talman, R.

    1990-09-01

    Successful operation of the Superconducting Supercollider (SSC) will depend on the stable circulation of particles for tens of millions of turns around the rings, in the presence of small nonlinear deflecting fields. One design challenge is to set specifications for the maximum allowable field imperfections of this sort, consistent with the required. stability. Another challenge is to plan for the inclusion of field compensating elements that will ameliorate the effects of errors. The tools'' available for projecting the long term stability are theoretical, both analytic and numerical, and experimental. These aspects are reviewed. 19 refs.

  17. The long term characteristics of greenschist

    NASA Astrophysics Data System (ADS)

    Jang, Bo-An

    2016-04-01

    The greenschist in the Jinping II Hydropower Station in southwest China exhibits continuous creep behaviour because of the geological conditions in the region. This phenomenon illustrates the time-dependent deformation and progressive damage that occurs after excavation. In this study, the responses of greenschist to stress over time were determined in a series of laboratory tests on samples collected from the access tunnel walls at the construction site. The results showed that the greenschist presented time-dependent behaviour under long-term loading. The samples generally experienced two stages: transient creep and steady creep, but no accelerating creep. The periods of transient creep and steady creep increased with increasing stress levels. The long-term strength of the greenschist was identified based on the variation of creep strain and creep rate. The ratio of long-term strength to conventional strength was around 80% and did not vary much with confining pressures. A quantitative method for predicting the failure period of greenschist, based on analysis of the stress-strain curve, is presented and implemented. At a confining pressure of 40 MPa, greenschist was predicted to fail in 5000 days under a stress of 290 MPa and to fail in 85 days under the stress of 320 MPa, indicating that the long-term strength identified by the creep rate and creep strain is a reliable estimate.

  18. Role of Subdural Electrocorticography in Prediction of Long-Term Seizure Outcome in Epilepsy Surgery

    ERIC Educational Resources Information Center

    Asano, Eishi; Juhasz, Csaba; Shah, Aashit; Sood, Sandeep; Chugani, Harry T.

    2009-01-01

    Since prediction of long-term seizure outcome using preoperative diagnostic modalities remains suboptimal in epilepsy surgery, we evaluated whether interictal spike frequency measures obtained from extraoperative subdural electrocorticography (ECoG) recording could predict long-term seizure outcome. This study included 61 young patients (age…

  19. Major depressive disorder subtypes to predict long-term course

    PubMed Central

    van Loo, Hanna M.; Cai, Tianxi; Gruber, Michael J.; Li, Junlong; de Jonge, Peter; Petukhova, Maria; Rose, Sherri; Sampson, Nancy A.; Schoevers, Robert A.; Wardenaar, Klaas J.; Wilcox, Marsha A.; Al-Hamzawi, Ali Obaid; Andrade, Laura Helena; Bromet, Evelyn J.; Bunting, Brendan; Fayyad, John; Florescu, Silvia E.; Gureje, Oye; Hu, Chiyi; Huang, Yueqin; Levinson, Daphna; Medina-Mora, Maria Elena; Nakane, Yoshibumi; Posada-Villa, Jose; Scott, Kate M.; Xavier, Miguel; Zarkov, Zahari; Kessler, Ronald C.

    2016-01-01

    Background Variation in course of major depressive disorder (MDD) is not strongly predicted by existing subtype distinctions. A new subtyping approach is considered here. Methods Two data mining techniques, ensemble recursive partitioning and Lasso generalized linear models (GLMs) followed by k-means cluster analysis, are used to search for subtypes based on index episode symptoms predicting subsequent MDD course in the World Mental Health (WMH) Surveys. The WMH surveys are community surveys in 16 countries. Lifetime DSM-IV MDD was reported by 8,261 respondents. Retrospectively reported outcomes included measures of persistence (number of years with an episode; number of with an episode lasting most of the year) and severity (hospitalization for MDD; disability due to MDD). Results Recursive partitioning found significant clusters defined by the conjunctions of early onset, suicidality, and anxiety (irritability, panic, nervousness-worry-anxiety) during the index episode. GLMs found additional associations involving a number of individual symptoms. Predicted values of the four outcomes were strongly correlated. Cluster analysis of these predicted values found three clusters having consistently high, intermediate, or low predicted scores across all outcomes. The high-risk cluster (30.0% of respondents) accounted for 52.9-69.7% of high persistence and severity and was most strongly predicted by index episode severe dysphoria, suicidality, anxiety, and early onset. A total symptom count, in comparison, was not a significant predictor. Conclusions Despite being based on retrospective reports, results suggest that useful MDD subtyping distinctions can be made using data mining methods. Further studies are needed to test and expand these results with prospective data. PMID:24425049

  20. Long-term Satellite Clock Bias Prediction Based on ARMA Model

    NASA Astrophysics Data System (ADS)

    Xi, C.; Cai, C. L.; Li, S. M.; Li, X. H.; Li, Z. B.; Deng, K. Q.

    2014-01-01

    The long-term and reliable prediction of satellite clock bias (SCB) is a key to implement the satellite autonomous navigation and orbit determination. Considering the shortcomings of the quadratic polynomial model (PM) and graysystem model (GM) in predicting the long-term SCB, a new prediction method of SCB that based on the ARMA (Auto-Regressive Moving Average) model is proposed to predict SCB, and show its property clearer. In this paper, a careful precision analysis of the 90-day SCB prediction is made to verify the feasibility and validity of this proposed method by using the IGS (International GNSS Service) clock data. According to the various changes of each satellite clock, the pattern recognition, modeling, and predicting are conducted, and the detailed comparison is made with the other three models at the same time. The results show that the ARMA model is reliable and valid to predict the long-term SCB.

  1. Long-term Clock Bias Prediction Based on An ARMA Model

    NASA Astrophysics Data System (ADS)

    Xi, Chao; Cai, Cheng-Lin; Li, Si-Min; Li, Xiao-Hui; Li, Zhi-Bin; Deng, Ke-Qun

    2014-07-01

    The long-term and reliable prediction of satellite clock bias (SCB) is an important prerequisite for realizing the satellite autonomous navigation and orbit determination. Considering the shortcomings of the quadratic polynomial model (PM) and gray system model (GM) in the long-term prediction of SCB, a new prediction method of SCB based on an ARMA (Auto-Regressive Moving Average) model is proposed to represent the variation characteristics of SCB more accurately. In this paper, a careful precision analysis of the 90-day SCB prediction is made to verify the feasibility and validity of this proposed method by using the IGS (International GNSS Service) clock data. According to the variation characteristics of each satellite clock, the pattern recognition, modeling and prediction of SCB are conducted, and the detailed comparison is made with the other three models at the same time. The results show that adopting the ARMA model can effectively improve the accuracy of long-term SCB prediction.

  2. Early Seizure Frequency and Aetiology Predict Long-Term Medical Outcome in Childhood-Onset Epilepsy

    ERIC Educational Resources Information Center

    Sillanpaa, Matti; Schmidt, Dieter

    2009-01-01

    In clinical practice, it is important to predict as soon as possible after diagnosis and starting treatment, which children are destined to develop medically intractable seizures and be at risk of increased mortality. In this study, we determined factors predictive of long-term seizure and mortality outcome in a population-based cohort of 102…

  3. Prediction of creep of polymer concrete

    SciTech Connect

    Khristova, Yu.; Aniskevich, K.

    1995-11-01

    We studied the applicability of the phenomenological approach to the prediction of long-time creep of polymer concrete consisting of polyester binder with diabase filler and diabase aggregate. We discovered that the principles of temperature-time analogy, of moisture-time analogy, and of temperature-moisture-time analogy are applicable to the description of the diagrams of short-time creep and to the prediction of long-time creep of polymer concrete at different temperatures and constant moisture content of the material.

  4. Operational improvements of long-term predicted ephemerides of the Tracking and Data Relay Satellites (TDRSs)

    NASA Technical Reports Server (NTRS)

    Kostoff, J. L.; Ward, D. T.; Cuevas, O. O.; Beckman, R. M.

    1995-01-01

    Tracking and Data Relay Satellite (TDRS) orbit determination and prediction are supported by the Flight Dynamics Facility (FDF) of the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD). TDRS System (TDRSS)-user satellites require predicted TDRS ephemerides that are up to 10 weeks in length. Previously, long-term ephemerides generated by the FDF included predictions from the White Sands Complex (WSC), which plans and executes TDRS maneuvers. TDRSs typically have monthly stationkeeping maneuvers, and predicted postmaneuver state vectors are received from WSC up to a month in advance. This paper presents the results of an analysis performed in the FDF to investigate more accurate and economical long-term ephemerides for the TDRSs. As a result of this analysis, two new methods for generating long-term TDRS ephemeris predictions have been implemented by the FDF. The Center-of-Box (COB) method models a TDRS as fixed at the center of its stationkeeping box. Using this method, long-term ephemeris updates are made semiannually instead of weekly. The impulse method is used to model more maneuvers. The impulse method yields better short-term accuracy than the COB method, especially for larger stationkeeping boxes. The accuracy of the impulse method depends primarily on the accuracy of maneuver date forecasting.

  5. Predicting long-term organic carbon dynamics in organically-amended soils using the CQESTR model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A process-based soil C model “CQESTR” was developed to simulate soil organic carbon (SOC) dynamics. The model has been validated successfully for North America, but needs to be tested in other geographic areas. We evaluated the predictive performance of CQESTR in a long-term (34-yr) SOC-depleted Eur...

  6. Evaluation and prediction of long-term environmental effects on nonmetallic materials

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Changes in functional properties of a broad spectrum of nonmetallic materials as a function of environment and exposure time were evaluated. Models for predicting long-term material performance are discussed. A literature search on specific materials in the space and simulated space environment was carried out and evaluated.

  7. Predicting agricultural management influence on long-term soil organic carbon dynamics: implications for biofuel production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations,...

  8. Temperamental factors predict long-term modifications of eating disorders after treatment

    PubMed Central

    2013-01-01

    Background Eating Disorders (EDs) are complex psychiatric pathologies characterized by moderate to poor response to treatment. Criteria of remission and recovery are not yet well defined. Simultaneously, personality plays a key role among the factors that determine treatment outcome. The aim of the present research is to evaluate the possibility of temperamental and character traits to predict the long-term outcome of ED. Method A sample of 25 AN and 28 BN female patients were re-assessed face-to-face after a minimum 5-years-follow-up through SCID-I, EDI-2 and TCI-R. Regression Analyses were performed to ascertain the possibility of TCI-R dimensions at the first visit to predict the long-term outcome. Results Clinical and psychopathological symptoms significantly decreased over the time and 23% of participants no longer received a categorical ED diagnosis after at least 5 years of follow-up. TCI-R dimensions failed to predict the absence of a DSM-IV-TR diagnosis in the long term, but Novelty Seeking, Harm Avoidance and Reward Dependence demonstrated to predict the clinical improvement of several EDI-2 scales. Conclusions Our results support the idea that temperamental dimensions are relevant to the long-term improvement of clinical variables of ED. Low Novelty Seeking is the strongest predictor of poor outcome. PMID:24200241

  9. Unsaturated consolidation theory for the prediction of long-term municipal solid waste landfill settlement.

    PubMed

    Liu, Chia-Nan; Chen, Rong-Her; Chen, Kuo-Sheng

    2006-02-01

    The understanding of long-term landfill settlement is important for landfill design and rehabilitation. However, suitable models that can consider both the mechanical and biodecomposition mechanisms in predicting the long-term landfill settlement are generally not available. In this paper, a model based on unsaturated consolidation theory and considering the biodegradation process is introduced to simulate the landfill settlement behaviour. The details of problem formulations and the derivation of the solution for the formulated differential equation of gas pressure are presented. A step-by-step analytical procedure employing this approach for estimating settlement is proposed. The proposed model can generally model the typical features of short-term and long-term behaviour. The proposed model also yields results that are comparable with the field measurements.

  10. On the accuracy of creep-damage predictions in thinwalled structures using the finite element method

    NASA Astrophysics Data System (ADS)

    Altenbach, H.; Kolarow, G.; Morachkovsky, O. K.; Naumenko, K.

    The constitutive model with a single damage parameter describing creep-damage behaviour of metals with respect to the different sensitivity of the damage process due to tension and compression is incorporated into the ANSYS finite element code by modifying the user defined creep material subroutine. The procedure is verified by comparison with solutions for beams and rectangular plates in bending based on the Ritz method. Various numerical tests show the sensitivity of long-term predictions to the mesh sizes and element types available for the creep analysis of thinwalled structures.

  11. Prediction of the Long-term Efficacy of STA-MCA Bypass by DSC-PI

    PubMed Central

    Hui, Li; Hui, Liu

    2016-01-01

    Abstract Superficial temporal artery-middle cerebral artery (STA-MCA) bypass [1,2] is an important and effective type of surgical revascularization that is widely used in the treatment of ischemic cerebral artery disease. However, a means of predicting its postoperative efficacy has not been established [3,4]. The present study analyzes the correlation between preoperative perfusion parameters (obtained using dynamic susceptibility contrast-enhanced perfusion imaging, DSC-PI) and postoperative long-term prognosis (using modified Rankin Scale, mRS scores). The preoperative perfusion parameters were defined by a combination of perfusion-weighted imaging and the Alberta Stroke Program Early Computerized Tomography Score (PWI-ASPECTS) and included cerebral blood flow (CBF)-ASPECTS, cerebral blood volume (CBV)-ASPECTS, mean transit time (MTT)-ASPECTS, and time to peak (TTP)-ASPECTS. Preoperative and postoperative scores were determined for 33 patients that received a unilateral STA-MCA bypass in order to discover the most reliable imaging predictive index as well as to define the threshold value for a favorable clinical outcome. The results showed that all of the PWI-ASPECTS scores were significantly negatively correlated with clinical prognosis. Receiver operating curve (ROC) analysis of the preoperative parameters in relation to long term prognosis showed the area under curve (AUC) was maximal for the CBF-ASPECTS score (P = 0.002). A preoperative score of less than six indicated a poor postoperative prognosis (sensitivity = 74.1%, specificity = 100%, AUC = 0.843). In conclusion, preoperative PWI-ASPECTS scores have been found useful as predictive indexes for the long-term prognosis of STA-MCA bypass patients, with higher scores indicating better postoperative long-term outcomes. As the most valuable prognostic indicator, the preoperative CBF-ASPECTS score has potential for use as a major index in screening and outcome prediction of patients under consideration for STA

  12. Prediction of the Long-term Efficacy of STA-MCA Bypass by DSC-PI.

    PubMed

    Hui, Li; Hui, Liu; Tong, Han

    2016-01-01

    Superficial temporal artery-middle cerebral artery (STA-MCA) bypass [1,2] is an important and effective type of surgical revascularization that is widely used in the treatment of ischemic cerebral artery disease. However, a means of predicting its postoperative efficacy has not been established [3,4]. The present study analyzes the correlation between preoperative perfusion parameters (obtained using dynamic susceptibility contrast-enhanced perfusion imaging, DSC-PI) and postoperative long-term prognosis (using modified Rankin Scale, mRS scores). The preoperative perfusion parameters were defined by a combination of perfusion-weighted imaging and the Alberta Stroke Program Early Computerized Tomography Score (PWI-ASPECTS) and included cerebral blood flow (CBF)-ASPECTS, cerebral blood volume (CBV)-ASPECTS, mean transit time (MTT)-ASPECTS, and time to peak (TTP)-ASPECTS. Preoperative and postoperative scores were determined for 33 patients that received a unilateral STA-MCA bypass in order to discover the most reliable imaging predictive index as well as to define the threshold value for a favorable clinical outcome. The results showed that all of the PWI-ASPECTS scores were significantly negatively correlated with clinical prognosis. Receiver operating curve (ROC) analysis of the preoperative parameters in relation to long term prognosis showed the area under curve (AUC) was maximal for the CBF-ASPECTS score (P = 0.002). A preoperative score of less than six indicated a poor postoperative prognosis (sensitivity = 74.1%, specificity = 100%, AUC = 0.843). In conclusion, preoperative PWI-ASPECTS scores have been found useful as predictive indexes for the long-term prognosis of STA-MCA bypass patients, with higher scores indicating better postoperative long-term outcomes. As the most valuable prognostic indicator, the preoperative CBF-ASPECTS score has potential for use as a major index in screening and outcome prediction of patients under consideration for STA

  13. Reduced Right Ventricular Function Predicts Long-Term Cardiac Re-Hospitalization after Cardiac Surgery

    PubMed Central

    Goldsmith, Yulia; Chan, Jacqueline; Iskandir, Marina; Gulkarov, Iosif; Tortolani, Anthony; Brener, Sorin J.; Sacchi, Terrence J.; Heitner, John F.

    2015-01-01

    Background The significance of right ventricular ejection fraction (RVEF), independent of left ventricular ejection fraction (LVEF), following isolated coronary artery bypass grafting (CABG) and valve procedures remains unknown. The aim of this study is to examine the significance of abnormal RVEF by cardiac magnetic resonance (CMR), independent of LVEF in predicting outcomes of patients undergoing isolated CABG and valve surgery. Methods From 2007 to 2009, 109 consecutive patients (mean age, 66 years; 38% female) were referred for pre-operative CMR. Abnormal RVEF and LVEF were considered <35% and <45%, respectively. Elective primary procedures include CABG (56%) and valve (44%). Thirty-day outcomes were perioperative complications, length of stay, cardiac re-hospitalizations and early mortaility; long-term (> 30 days) outcomes included, cardiac re-hospitalization, worsening congestive heart failure and mortality. Mean clinical follow up was 14 months. Findings Forty-eight patients had reduced RVEF (mean 25%) and 61 patients had normal RVEF (mean 50%) (p<0.001). Fifty-four patients had reduced LVEF (mean 30%) and 55 patients had normal LVEF (mean 59%) (p<0.001). Patients with reduced RVEF had a higher incidence of long-term cardiac re-hospitalization vs. patients with normal RVEF (31% vs.13%, p<0.05). Abnormal RVEF was a predictor for long-term cardiac re-hospitalization (HR 3.01 [CI 1.5-7.9], p<0.03). Reduced LVEF did not influence long-term cardiac re-hospitalization. Conclusion Abnormal RVEF is a stronger predictor for long-term cardiac re-hospitalization than abnormal LVEF in patients undergoing isolated CABG and valve procedures. PMID:26197273

  14. A Statistical Test for Identifying the Number of Creep Regimes When Using the Wilshire Equations for Creep Property Predictions

    NASA Astrophysics Data System (ADS)

    Evans, Mark

    2016-12-01

    A new parametric approach, termed the Wilshire equations, offers the realistic potential of being able to accurately lift materials operating at in-service conditions from accelerated test results lasting no more than 5000 hours. The success of this approach can be attributed to a well-defined linear relationship that appears to exist between various creep properties and a log transformation of the normalized stress. However, these linear trends are subject to discontinuities, the number of which appears to differ from material to material. These discontinuities have until now been (1) treated as abrupt in nature and (2) identified by eye from an inspection of simple graphical plots of the data. This article puts forward a statistical test for determining the correct number of discontinuities present within a creep data set and a method for allowing these discontinuities to occur more gradually, so that the methodology is more in line with the accepted view as to how creep mechanisms evolve with changing test conditions. These two developments are fully illustrated using creep data sets on two steel alloys. When these new procedures are applied to these steel alloys, not only do they produce more accurate and realistic looking long-term predictions of the minimum creep rate, but they also lead to different conclusions about the mechanisms determining the rates of creep from those originally put forward by Wilshire.

  15. Role of subdural electrocorticography in prediction of long-term seizure outcome in epilepsy surgery

    PubMed Central

    Juhász, Csaba; Shah, Aashit; Sood, Sandeep; Chugani, Harry T.

    2009-01-01

    Since prediction of long-term seizure outcome using preoperative diagnostic modalities remains suboptimal in epilepsy surgery, we evaluated whether interictal spike frequency measures obtained from extraoperative subdural electrocorticography (ECoG) recording could predict long-term seizure outcome. This study included 61 young patients (age 0.4–23.0 years), who underwent extraoperative ECoG recording prior to cortical resection for alleviation of uncontrolled focal seizures. Patient age, frequency of preoperative seizures, neuroimaging findings, ictal and interictal ECoG measures were preoperatively obtained. The seizure outcome was prospectively measured [follow-up period: 2.5–6.4 years (mean 4.6 years)]. Univariate and multivariate logistic regression analyses determined how well preoperative demographic and diagnostic measures predicted long-term seizure outcome. Following the initial cortical resection, Engel Class I, II, III and IV outcomes were noted in 35, 6, 12 and 7 patients, respectively. One child died due to disseminated intravascular coagulation associated with pseudomonas sepsis 2 days after surgery. Univariate regression analyses revealed that incomplete removal of seizure onset zone, higher interictal spike-frequency in the preserved cortex and incomplete removal of cortical abnormalities on neuroimaging were associated with a greater risk of failing to obtain Class I outcome. Multivariate logistic regression analysis revealed that incomplete removal of seizure onset zone was the only independent predictor of failure to obtain Class I outcome. The goodness of regression model fit and the predictive ability of regression model were greatest in the full regression model incorporating both ictal and interictal measures [R2 0.44; Area under the receiver operating characteristic (ROC) curve: 0.81], slightly smaller in the reduced model incorporating ictal but not interictal measures (R2 0.40; Area under the ROC curve: 0.79) and slightly smaller

  16. Predictive Factors Affecting Long-Term Outcome of Unilateral Lateral Rectus Recession

    PubMed Central

    Yang, Hee Kyung; Kim, Mi-Jin; Hwang, Jeong-Min

    2015-01-01

    Background There are few long-term outcome reports of unilateral lateral rectus (LR) recession for exotropia including a large number of subjects. Previous reports on unilateral LR recession commonly show extremely low rates of initial overcorrection and large exodrifts after surgery suggesting that the surgical dose may be increased. However, little is known of the long-term outcome of a large unilateral LR recession for exotropia. Objectives To determine long-term outcomes and predictive factors of recurrence after a large unilateral LR recession in patients with exotropia. Data Extraction Retrospective analysis was performed on 92 patients aged 3 to 17 years who underwent 10 mm unilateral LR recession for exotropia of ≤ 25 prism diopters (Δ) with prism and alternate cover testing and were followed up for more than 2 years after surgery. Final success rates within 10Δ of exophoria/tropia and 5Δ of esophoria/tropia at distance in the primary position, improvement in stereopsis and the predictive factors for recurrence were evaluated. Results At 24 months after surgery, 54% of patients had ocular alignment meeting the defined criteria of success, 45% had recurrence and 1% had overcorrection. After a mean follow-up of 39 months, 36% showed success, 63% showed recurrence and 1% resulted in overcorrection. The average time of recurrence was 23.4±14.7 months (range, 1–60 months) and the rate of recurrence per person-year was 23% after unilateral LR recession. Predictive factors of recurrence were a larger preoperative near angle of deviation (>16Δ) and larger initial postoperative exodeviation (>5Δ) at distance. Conclusions Long-term outcome of unilateral LR recession for exotropia showed low success rates with high recurrence, thus should be reserved for patients with a small preoperative near angle of exodeviation. PMID:26418819

  17. Wear, creep, and frictional heating of femoral implant articulating surfaces and the effect on long-term performance--Part II, Friction, heating, and torque.

    PubMed

    Davidson, J A; Schwartz, G; Lynch, G; Gir, S

    1988-04-01

    In Part I, (J.A. Davidson and G. Schwartz, "Wear, creep, and frictional heating of femoral implant articulating surfaces and the effect on long-term performance--Part I, A review," J. Biomed. Mater. Res., 21, 000-000 (1987) it was shown that lubrication of the artificial hip joint was complex and that long-term performance is governed by the combined wear, creep, and to a lesser extent, oxidation degradation of the articulating materials. Importantly, it was shown that a tendency for heating exists during articulation in the hip joint and that elevated temperatures can increase the wear, creep, and oxidation degradation rate of UHMWPE. The present study was performed to examine closely the propensity to generate heat during articulation in a hip joint simulator. The systems investigated were polished Co-Cr-Mo alloy articulating against UHMWPE, polished alumina ceramic against UHMWPE, and polished alumina against itself. Frictional torque was also evaluated for each system at various levels of applied loads. A walking load history was used in both the frictional heating and torque tests. The majority of tests were performed with 5 mL of water lubricant. However, the effect of various concentrations of hyaluronic acid was also evaluated. Results showed frictional heating to occur in all three systems, reaching an equilibrium after roughly 30 min articulation time. Ceramic systems showed reduced levels of heating compared to the cobalt alloy-UHMWPE system. The level of frictional torque for each system ranked similar to their respective tendencies to generate heat. Hyaluronic acid had little effect, while dry conditions and the presence of small quantities of bone cement powder in water lubricant significantly increased frictional torque.

  18. Worldwide impact of aerosol's time scale on the predicted long-term concentrating solar power potential.

    PubMed

    Ruiz-Arias, Jose A; Gueymard, Christian A; Santos-Alamillos, Francisco J; Pozo-Vázquez, David

    2016-08-10

    Concentrating solar technologies, which are fuelled by the direct normal component of solar irradiance (DNI), are among the most promising solar technologies. Currently, the state-of the-art methods for DNI evaluation use datasets of aerosol optical depth (AOD) with only coarse (typically monthly) temporal resolution. Using daily AOD data from both site-specific observations at ground stations as well as gridded model estimates, a methodology is developed to evaluate how the calculated long-term DNI resource is affected by using AOD data averaged over periods from 1 to 30 days. It is demonstrated here that the use of monthly representations of AOD leads to systematic underestimations of the predicted long-term DNI up to 10% in some areas with high solar resource, which may result in detrimental consequences for the bankability of concentrating solar power projects. Recommendations for the use of either daily or monthly AOD data are provided on a geographical basis.

  19. Predicting and mitigating future biodiversity loss using long-term ecological proxies

    NASA Astrophysics Data System (ADS)

    Fordham, Damien A.; Akçakaya, H. Resit; Alroy, John; Saltré, Frédérik; Wigley, Tom M. L.; Brook, Barry W.

    2016-10-01

    Uses of long-term ecological proxies in strategies for mitigating future biodiversity loss are too limited in scope. Recent advances in geochronological dating, palaeoclimate reconstructions and molecular techniques for inferring population dynamics offer exciting new prospects for using retrospective knowledge to better forecast and manage ecological outcomes in the face of global change. Opportunities include using fossils, genes and computational models to identify ecological traits that caused species to be differentially prone to regional and range-wide extinction, test if threatened-species assessment approaches work and locate habitats that support stable ecosystems in the face of shifting climates. These long-term retrospective analyses will improve efforts to predict the likely effects of future climate and other environmental change on biodiversity, and target conservation management resources most effectively.

  20. Effect of Tungsten on Long-Term Microstructural Evolution and Impression Creep Behavior of 9Cr Reduced Activation Ferritic/Martensitic Steel

    NASA Astrophysics Data System (ADS)

    Thomas Paul, V.; Vijayanand, V. D.; Sudha, C.; Saroja, S.

    2017-01-01

    The present study describes the changes in the creep properties associated with microstructural evolution during thermal exposures to near service temperatures in indigenously developed reduced activation ferritic-martensitic steels with varying tungsten (1 and 1.4 wt pct W) contents. The creep behavior has been studied employing impression creep (IC) test, and the changes in impression creep behavior with tungsten content have been correlated with the observed microstructures. The results of IC test showed that an increase in 0.4 pct W decreases the creep rate to nearly half the value. Creep strength of 1.4 pct W steel showed an increase in steels aged for short durations which decreased as aging time increased. The microstructural changes include coarsening of precipitates, reduction in dislocation density, changes in microchemistry, and formation of new phases. The formation of various phases and their volume fractions have been predicted using the JMatPro software for the two steels and validated by experimental methods. Detailed transmission electron microscopy analysis shows coarsening of precipitates and formation of a discontinuous network of Laves phase in 1.4 W steel aged for 10,000 hours at 823 K (550 °C) which is in agreement with the JMatPro simulation results.

  1. Review of uncertainty sources affecting the long-term predictions of space debris evolutionary models

    NASA Astrophysics Data System (ADS)

    Dolado-Perez, J. C.; Pardini, Carmen; Anselmo, Luciano

    2015-08-01

    Since the launch of Sputnik-I in 1957, the amount of space debris in Earth's orbit has increased continuously. Historically, besides abandoned intact objects (spacecraft and orbital stages), the primary sources of space debris in Earth's orbit were (i) accidental and intentional break-ups which produced long-lasting debris and (ii) debris released intentionally during the operation of launch vehicle orbital stages and spacecraft. In the future, fragments generated by collisions are expected to become a significant source as well. In this context, and from a purely mathematical point of view, the orbital debris population in Low Earth Orbit (LEO) should be intrinsically unstable, due to the physics of mutual collisions and the relative ineffectiveness of natural sink mechanisms above~700 km. Therefore, the real question should not be "if", but "when" the exponential growth of the space debris population is supposed to start. From a practical point of view, and in order to answer the previous question, since the end of the 1980's several sophisticated long-term debris evolutionary models have been developed. Unfortunately, the predictions performed with such models, in particular beyond a few decades, are affected by considerable uncertainty. Such uncertainty comes from a relative important number of variables that being either under the partial control or completely out of the control of modellers, introduce a variability on the long-term simulation of the space debris population which cannot be captured with standard Monte Carlo statistics. The objective of this paper is to present and discuss many of the uncertainty sources affecting the long-term predictions done with evolutionary models, in order to serve as a roadmap for the uncertainty and the statistical robustness analysis of the long-term evolution of the space debris population.

  2. A Long-Term Prediction Model of Beijing Haze Episodes Using Time Series Analysis

    PubMed Central

    Zhang, Zhongqiu; Sun, Liren; Xu, Cui

    2016-01-01

    The rapid industrial development has led to the intermittent outbreak of pm2.5 or haze in developing countries, which has brought about great environmental issues, especially in big cities such as Beijing and New Delhi. We investigated the factors and mechanisms of haze change and present a long-term prediction model of Beijing haze episodes using time series analysis. We construct a dynamic structural measurement model of daily haze increment and reduce the model to a vector autoregressive model. Typical case studies on 886 continuous days indicate that our model performs very well on next day's Air Quality Index (AQI) prediction, and in severely polluted cases (AQI ≥ 300) the accuracy rate of AQI prediction even reaches up to 87.8%. The experiment of one-week prediction shows that our model has excellent sensitivity when a sudden haze burst or dissipation happens, which results in good long-term stability on the accuracy of the next 3–7 days' AQI prediction. PMID:27597861

  3. Long-term prediction test procedure for most ICs, based on linear response theory

    NASA Technical Reports Server (NTRS)

    Litovchenko, V.; Ivakhnenko, I.

    1991-01-01

    Experimentally, thermal annealing is known to be a factor which enables a number of different integrated circuits (IC's) to recover their operating characteristics after suffering radiation damage in the space radiation environment; thus, decreasing and limiting long term cumulative total-dose effects. This annealing is also known to be accelerated at elevated temperatures both during and after irradiation. Linear response theory (LRT) was applied, and a linear response function (LRF) to predict the radiation/annealing response of sensitive parameters of IC's for long term (several months or years) exposure to the space radiation environment were constructed. Compressing the annealing process from several years in orbit to just a few hours or days in the laboratory is achieved by subjecting the IC to elevated temperatures or by increasing the typical spaceflight dose rate by several orders of magnitude for simultaneous radiation/annealing only. The accomplishments are as follows: (1) the test procedure to make predictions of the radiation response was developed; (2) the calculation of the shift in the threshold potential due to the charge distribution in the oxide was written; (3) electron tunneling processes from the bulk Si to the oxide region in an MOS IC were estimated; (4) in order to connect the experimental annealing data to the theoretical model, constants of the model of the basic annealing process were established; (5) experimental data obtained at elevated temperatures were analyzed; (6) time compression and reliability of predictions for the long term region were shown; (7) a method to compress test time and to make predictions of response for the nonlinear region was proposed; and (8) nonlinearity of the LRF with respect to log(t) was calculated theoretically from a model.

  4. Does Screening Classification Predict Long-Term Outcomes of DWI Offenders?

    PubMed Central

    Lapham, Sandra

    2010-01-01

    Objectives We interviewed 583 driving while intoxicated (DWI) first offenders with substance use disorders (SUDs) to determine the usefulness of a screening classification system in predicting treatment utilization, current SUD, and driving over the alcohol limit (DOL) at 15-year follow-ups. Methods Univariate and multivariate statistics were used to determine predictors of long-term outcomes. Results Screening classification defined groups with different treatment histories and 15-year outcomes. Current SUDs were reported by 21%, and DOL by 10%, of subjects. Conclusions Group differences suggest that screening data could be used more effectively to triage and treat DWI offenders. PMID:20604698

  5. Assessing Long-Term Wind Conditions by Combining Different Measure-Correlate-Predict Algorithms: Preprint

    SciTech Connect

    Zhang, J.; Chowdhury, S.; Messac, A.; Hodge, B. M.

    2013-08-01

    This paper significantly advances the hybrid measure-correlate-predict (MCP) methodology, enabling it to account for variations of both wind speed and direction. The advanced hybrid MCP method uses the recorded data of multiple reference stations to estimate the long-term wind condition at a target wind plant site. The results show that the accuracy of the hybrid MCP method is highly sensitive to the combination of the individual MCP algorithms and reference stations. It was also found that the best combination of MCP algorithms varies based on the length of the correlation period.

  6. Deterministic and Probabilistic Creep and Creep Rupture Enhancement to CARES/Creep: Multiaxial Creep Life Prediction of Ceramic Structures Using Continuum Damage Mechanics and the Finite Element Method

    NASA Technical Reports Server (NTRS)

    Jadaan, Osama M.; Powers, Lynn M.; Gyekenyesi, John P.

    1998-01-01

    High temperature and long duration applications of monolithic ceramics can place their failure mode in the creep rupture regime. A previous model advanced by the authors described a methodology by which the creep rupture life of a loaded component can be predicted. That model was based on the life fraction damage accumulation rule in association with the modified Monkman-Grant creep ripture criterion However, that model did not take into account the deteriorating state of the material due to creep damage (e.g., cavitation) as time elapsed. In addition, the material creep parameters used in that life prediction methodology, were based on uniaxial creep curves displaying primary and secondary creep behavior, with no tertiary regime. The objective of this paper is to present a creep life prediction methodology based on a modified form of the Kachanov-Rabotnov continuum damage mechanics (CDM) theory. In this theory, the uniaxial creep rate is described in terms of stress, temperature, time, and the current state of material damage. This scalar damage state parameter is basically an abstract measure of the current state of material damage due to creep deformation. The damage rate is assumed to vary with stress, temperature, time, and the current state of damage itself. Multiaxial creep and creep rupture formulations of the CDM approach are presented in this paper. Parameter estimation methodologies based on nonlinear regression analysis are also described for both, isothermal constant stress states and anisothermal variable stress conditions This creep life prediction methodology was preliminarily added to the integrated design code CARES/Creep (Ceramics Analysis and Reliability Evaluation of Structures/Creep), which is a postprocessor program to commercially available finite element analysis (FEA) packages. Two examples, showing comparisons between experimental and predicted creep lives of ceramic specimens, are used to demonstrate the viability of this methodology and

  7. Predicting and comparing long-term measles antibody profiles of different immunization policies.

    PubMed Central

    Lee, M. S.; Nokes, D. J.

    2001-01-01

    OBJECTIVE: Measles outbreaks are infrequent and localized in areas with high coverage of measles vaccine. The need is to assess long-term effectiveness of coverage. Since 1991, no measles epidemic affecting the whole island has occurred in Taiwan, China. Epidemiological models are developed to predict the long-term measles antibody profiles and compare the merits of different immunization policies on the island. METHODS: The current measles immunization policy in Taiwan, China, is 1 dose of measles vaccine at 9 months of age and 1 dose of measles, mumps and rubella (MMR) vaccine at 15 months of age, plus a 'mop-up' of MMR-unvaccinated schoolchildren at 6 years of age. Refinements involve a change to a two-dose strategy. Five scenarios based on different vaccination strategies are compared. The models are analysed using Microsoft Excel. FINDINGS: First, making the assumption that measles vaccine-induced immunity will not wane, the predicted measles IgG seroprevalences in preschool children range from 81% (lower bound) to 94% (upper bound) and in schoolchildren reach 97-98% in all strategy scenarios. Results are dependent on the association of vaccine coverage between the first and second dose of vaccine. Second, if it is assumed that vaccine-induced antibody titres decay, the long-term measles seroprevalence will depend on the initial titres post vaccination, decay rates of antibody titres and cut-off of seropositivity. CONCLUSION: If MMR coverage at 12 months of age can reach > 90%, it would be worth changing the current policy to 2 doses at 12 months and 6 years of age to induce higher antibody titres. These epidemiological models could be applied wherever a similar stage of measles elimination has been reached. PMID:11477964

  8. Development of an integrated method for long-term water quality prediction using seasonal climate forecast

    NASA Astrophysics Data System (ADS)

    Cho, Jaepil; Shin, Chang-Min; Choi, Hwan-Kyu; Kim, Kyong-Hyeon; Choi, Ji-Yong

    2016-10-01

    The APEC Climate Center (APCC) produces climate prediction information utilizing a multi-climate model ensemble (MME) technique. In this study, four different downscaling methods, in accordance with the degree of utilizing the seasonal climate prediction information, were developed in order to improve predictability and to refine the spatial scale. These methods include: (1) the Simple Bias Correction (SBC) method, which directly uses APCC's dynamic prediction data with a 3 to 6 month lead time; (2) the Moving Window Regression (MWR) method, which indirectly utilizes dynamic prediction data; (3) the Climate Index Regression (CIR) method, which predominantly uses observation-based climate indices; and (4) the Integrated Time Regression (ITR) method, which uses predictors selected from both CIR and MWR. Then, a sampling-based temporal downscaling was conducted using the Mahalanobis distance method in order to create daily weather inputs to the Soil and Water Assessment Tool (SWAT) model. Long-term predictability of water quality within the Wecheon watershed of the Nakdong River Basin was evaluated. According to the Korean Ministry of Environment's Provisions of Water Quality Prediction and Response Measures, modeling-based predictability was evaluated by using 3-month lead prediction data issued in February, May, August, and November as model input of SWAT. Finally, an integrated approach, which takes into account various climate information and downscaling methods for water quality prediction, was presented. This integrated approach can be used to prevent potential problems caused by extreme climate in advance.

  9. Long-Term Predictions of Global Climate Using the Ocean Conveyor

    SciTech Connect

    Ray, P.; Wilson, J.R.

    2003-01-01

    Many have attributed the Great Ocean Conveyor as a major driver of global climate change over millennia as well as a possible explanation for shorter (multidecadal) oscillations. The conveyor is thought to have a cycle time on the order of 1000 years, however recent research has suggested that it is much faster than previously believed (about 100 years). A faster conveyor leads to the possibility of the conveyor's role in even shorter oscillations such as the El Nino/Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). The conveyor is primarily density driven. In this study the salty outflow of the Red Sea is used to predict its behavior ten years into the future. A successful model could lead to a long-term prediction (ten years) of El Ninos, Atlantic hurricane season intensity, as well as global temperature and precipitation patterns.

  10. Long-term polar motion prediction using normal time-frequency transform

    NASA Astrophysics Data System (ADS)

    Su, Xiaoqing; Liu, Lintao; Houtse, Hsu; Wang, Guocheng

    2014-02-01

    This paper presents normal time-frequency transform (NTFT) application in harmonic/quasi-harmonic signal prediction. Particularly, we use the normal wavelet transform (a special NTFT) to make long-term polar motion prediction. Instantaneous frequency, phase and amplitude of Chandler wobble, prograde and retrograde annual wobbles of Earth's polar motion are analyzed via the NTFT. Results show that the three main wobbles can be treated as quasi-harmonic processes. Current instantaneous harmonic information of the three wobbles can be acquired by the NTFT that has a kernel function constructed with a normal half-window function. Based on this information, we make the polar motion predictions with lead times of 1 year and 5 years. Results show that our prediction skills are very good with long lead time. An abnormality in the predictions occurs during the second half of 2005 and first half of 2006. Finally, we provide the future (starting from 2013) polar motion predictions with 1- and 5-year leads. These predictions will be used to verify the effectiveness of the method proposed in this paper.

  11. Soft tissue profile changes following mandibular advancement surgery: predictability and long-term outcome.

    PubMed

    Mobarak, K A; Espeland, L; Krogstad, O; Lyberg, T

    2001-04-01

    The objectives of this cephalometric study were to assess long-term changes in the soft tissue profile following mandibular advancement surgery and to investigate the relationship between soft tissue and hard tissue movements. The sample consisted of 61 patients treated consecutively for mandibular retrognathism with orthodontic therapy combined with bilateral sagittal split osteotomy and rigid fixation. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Postsurgical changes in the upper and the lower lips and the mentolabial fold were more pronounced among low-angle cases compared with high-angle cases. In accordance with other studies, the soft tissue chin and the mentolabial fold were generally found to follow their underlying skeletal structures in a 1:1 ratio. Because of the strong influence skeletal relapse has on soft tissue profile changes, alternative ratios of soft tissue-to-hard tissue movement that accounted for mean relapse were also generated. It is suggested that if a more realistic long-term prediction of the postsurgical soft tissue profile is desirable, then ratios incorporating mean relapse should be used rather than estimates based on a 1:1 relationship.

  12. Long-term prediction of the Arctic ionospheric TEC based on time-varying periodograms.

    PubMed

    Liu, Jingbin; Chen, Ruizhi; Wang, Zemin; An, Jiachun; Hyyppä, Juha

    2014-01-01

    Knowledge of the polar ionospheric total electron content (TEC) and its future variations is of scientific and engineering relevance. In this study, a new method is developed to predict Arctic mean TEC on the scale of a solar cycle using previous data covering 14 years. The Arctic TEC is derived from global positioning system measurements using the spherical cap harmonic analysis mapping method. The study indicates that the variability of the Arctic TEC results in highly time-varying periodograms, which are utilized for prediction in the proposed method. The TEC time series is divided into two components of periodic oscillations and the average TEC. The newly developed method of TEC prediction is based on an extrapolation method that requires no input of physical observations of the time interval of prediction, and it is performed in both temporally backward and forward directions by summing the extrapolation of the two components. The backward prediction indicates that the Arctic TEC variability includes a 9 years period for the study duration, in addition to the well-established periods. The long-term prediction has an uncertainty of 4.8-5.6 TECU for different period sets.

  13. Short and long term improvements in quality of chronic care delivery predict program sustainability.

    PubMed

    Cramm, Jane Murray; Nieboer, Anna Petra

    2014-01-01

    Empirical evidence on sustainability of programs that improve the quality of care delivery over time is lacking. Therefore, this study aims to identify the predictive role of short and long term improvements in quality of chronic care delivery on program sustainability. In this longitudinal study, professionals [2010 (T0): n=218, 55% response rate; 2011 (T1): n=300, 68% response rate; 2012 (T2): n=265, 63% response rate] from 22 Dutch disease-management programs completed surveys assessing quality of care and program sustainability. Our study findings indicated that quality of chronic care delivery improved significantly in the first 2 years after implementation of the disease-management programs. At T1, overall quality, self-management support, delivery system design, and integration of chronic care components, as well as health care delivery and clinical information systems and decision support, had improved. At T2, overall quality again improved significantly, as did community linkages, delivery system design, clinical information systems, decision support and integration of chronic care components, and self-management support. Multilevel regression analysis revealed that quality of chronic care delivery at T0 (p<0.001) and quality changes in the first (p<0.001) and second (p<0.01) years predicted program sustainability. In conclusion this study showed that disease-management programs based on the chronic care model improved the quality of chronic care delivery over time and that short and long term changes in the quality of chronic care delivery predicted the sustainability of the projects.

  14. An empirical approach to predicting long term behavior of metal particle based recording media

    NASA Technical Reports Server (NTRS)

    Hadad, Allan S.

    1992-01-01

    Alpha iron particles used for magnetic recording are prepared through a series of dehydration and reduction steps of alpha-Fe2O3-H2O resulting in acicular, polycrystalline, body centered cubic (bcc) alpha-Fe particles that are single magnetic domains. Since fine iron particles are pyrophoric by nature, stabilization processes had to be developed in order for iron particles to be considered as a viable recording medium for long term archival (i.e., 25+ years) information storage. The primary means of establishing stability is through passivation or controlled oxidation of the iron particle's surface. A study was undertaken to examine the degradation in magnetic properties as a function of both temperature and humidity on silicon-containing iron particles between 50-120 C and 3-89 percent relative humidity. The methodology to which experimental data was collected and analyzed leading to predictive capability is discussed.

  15. Long-term optical reliability and lifetime predictability of double clad fibers

    NASA Astrophysics Data System (ADS)

    Abramczyk, Jaroslaw; Govindarajan, Harish; Cunningham, Wells; Guertin, Douglas; Tankala, Kanishka

    2015-03-01

    With the use of fiber lasers pervading diverse applications and environmental conditions, the long-term reliability of low index (LI) polymer coated double-clad (DC) fibers used for this purpose is significant. Mechanical reliability standards for 125um fibers are well established by Telcordia GR-20-CORE requirements and some work1 has been published investigating optical reliability of DC fibers with specially engineered coatings with respect to accelerated temperature and humidity aging. While these are helpful in providing a figure of merit to the optical reliability of LI fluoroacrylate coatings, it becomes important to decouple the effects of temperature and humidity in order to understand the underlying degradation mechanisms of LI polymers in various storage and operating environments. This paper identifies the effects of temperature and humidity on the spectral attenuation of DC fibers and presents a reliability model capable of predicting lifetimes under prolonged exposure to typical temperature and humidity conditions experienced during storage and operation of fiber lasers.

  16. Anger Problems Predict Long-Term Criminal Recidivism in Partner Violent Men.

    PubMed

    Farzan-Kashani, Julian; Murphy, Christopher M

    2015-08-18

    The current study investigated the influence of anger problems on partner violent men's long-term response to treatment, as indicated by criminal recidivism during an 8-year period after treatment initiation. Participants were 132 men who presented for treatment services at a community-based domestic violence agency. Results indicated that individuals with extensive anger problems had more charges for general violence (GV) offenses and more ongoing problems with protection orders than did those with Normal Anger (NA) profiles. Examinations of specific anger scales indicated that low Anger Control (LAC) and high Anger Expression predict GV recidivism. These findings indicate that a standard cognitive-behavioral treatment program may not adequately reduce the recidivism risk of partner violent men with pronounced anger problems, stress the importance of further research to understand the role of anger problems in partner violence treatment, and highlight the need to develop and evaluate new intervention approaches for partner violent men with serious anger dysregulation.

  17. Impact of microbial activity on the radioactive waste disposal: long term prediction of biocorrosion processes.

    PubMed

    Libert, Marie; Schütz, Marta Kerber; Esnault, Loïc; Féron, Damien; Bildstein, Olivier

    2014-06-01

    This study emphasizes different experimental approaches and provides perspectives to apprehend biocorrosion phenomena in the specific disposal environment by investigating microbial activity with regard to the modification of corrosion rate, which in turn can have an impact on the safety of radioactive waste geological disposal. It is found that iron-reducing bacteria are able to use corrosion products such as iron oxides and "dihydrogen" as new energy sources, especially in the disposal environment which contains low amounts of organic matter. Moreover, in the case of sulphate-reducing bacteria, the results show that mixed aerobic and anaerobic conditions are the most hazardous for stainless steel materials, a situation which is likely to occur in the early stage of a geological disposal. Finally, an integrated methodological approach is applied to validate the understanding of the complex processes and to design experiments aiming at the acquisition of kinetic data used in long term predictive modelling of biocorrosion processes.

  18. Stress and reward: long term cortisol exposure predicts the strength of sexual preference.

    PubMed

    Chumbley, J R; Hulme, O; Köchli, H; Russell, E; Van Uum, S; A Pizzagalli, D; Fehr, E

    2014-05-28

    Healthy individuals tend to consume available rewards like food and sex. This tendency is attenuated or amplified in most stress-related psychiatric conditions, so we asked if it depends on endogenous levels of the 'canonical stress hormone' cortisol. We unobtrusively quantified how hard healthy heterosexual men would work to consume erotic images of women versus men and also measured their exposure to endogenous cortisol in the prior two months. We used linear models to predict the strength of sexual preference from cortisol level, after accounting for other potential explanations. Heterosexual preference declines with self-reported anhedonia but increases with long term exposure to endogenous cortisol. These results suggest that cortisol may affect reward-related behavior in healthy adults.

  19. Climate change forecasts, long-term spatio-temporal prediction and the resilience of dry ecosystems

    NASA Astrophysics Data System (ADS)

    Shafran-Natan, Rakefet; Svoray, Tal; Avi, Perevolotsky

    2010-05-01

    Primary production is an important indicator to climatic changes in drylands, while reduction in productivity has many consequences on ecosystem functioning. We suggest that the response of dry ecosystems to climate change should lead to a change in spatial patterns of grasses without a substantial change in ecosystem resilience. We used field data and a recently published spatio-temporally explicit model to study factors affecting long-term variation in primary production in two dry ecosystems: semi-arid (SAE) and Mediterranean (DME) dominated by annual vegetation. The model was operated in both patch and landscape scales and was executed along 30 years (1979-2008) at SAE and along 21 years (1986-1990; 1993-2008) at DME. Model predictions were validated against samples that were harvested in each site at the end of the growing season, over 15 seasons (1994-2008) at SAE (0.63

  20. SY 04-2 LONG-TERM CVD RISK PREDICTION IN LOW-INCIDENCE EUROPEAN POPULATIONS.

    PubMed

    Veronesi, Giovanni

    2016-09-01

    In Italy, the European SCORE Project risk score is the recommended tool for cardiovascular disease risk stratification in the primary prevention setting. Among non-diabetic subjects aged 40 to 64, the model estimates the 10-year probability of death due to cardiovascular disease based on individual's age, total cholesterol, blood pressure and smoking status. A growing body of evidence suggests that in middle-aged adults this stratification may suffer from two major drawbacks. First, mortality risk severely underestimates the global burden of disease incidence. Second, younger individuals and women are likely to be classified in the "low 10-year risk" category despite the presence of risk factors.The latest European and American guidelines have eventually introduced the assessment of long-term risk of disease as additional tool to improve risk communication and increase risk awareness. Long-term risk scores were first developed in the US and in the UK, i.e. in high-risk populations. In low-incidence populations, these models may have poor calibration and discrimination ability, as shown for the Framingham equation. Therefore, our research team developed and validated a 20-year risk score for the Italian population. As part of a collaborative study with the Italian Health Institute, we pooled 7 population-based cohorts of middle-aged individuals recruited in Northern and in Central Italy in mid 1980 s and early 1990 s following a similar protocol with standardized MONICA procedures. Overall, more than 10500 men and women 35-69 years old and free of CVD at baseline, who developed 830 first major atherosclerotic events (coronary heart disease or ischemic strokes) during a median 17 years of follow-up. The score was based on traditional risk factors (age, blood lipids, systolic blood pressure and treatment, smoking and diabetes). In addition, social status and family history of coronary heart disease did improve risk prediction, at least in men. Finally we showed

  1. An empirical approach to predicting long term behavior of metal particle based recording media

    NASA Technical Reports Server (NTRS)

    Hadad, Allan S.

    1991-01-01

    Alpha iron particles used for magnetic recording are prepared through a series of dehydration and reduction steps of alpha-Fe2O3-H2O resulting in acicular, polycrystalline, body centered cubic (bcc) alpha-Fe particles that are single magnetic domains. Since fine iron particles are pyrophoric by nature, stabilization processes had to be developed in order for iron particles to be considered as a viable recording medium for long term archival (i.e., 25+ years) information storage. The primary means of establishing stability is through passivation or controlled oxidation of the iron particle's surface. Since iron particles used for magnetic recording are small, additional oxidation has a direct impact on performance especially where archival storage of recorded information for long periods of time is important. Further stabilization chemistry/processes had to be developed to guarantee that iron particles could be considered as a viable long term recording medium. In an effort to retard the diffusion of iron ions through the oxide layer, other elements such as silicon, aluminum, and chromium have been added to the base iron to promote more dense scale formation or to alleviate some of the non-stoichiometric behavior of the oxide or both. The presence of water vapor has been shown to disrupt the passive layer, subsequently increasing the oxidation rate of the iron. A study was undertaken to examine the degradation in magnetic properties as a function of both temperature and humidity on silicon-containing iron particles between 50-120 deg C and 3-89 percent relative humidity. The methodology to which experimental data was collected and analyzed leading to predictive capability is discussed.

  2. Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction

    PubMed Central

    Bang, Woo-Dae; Kim, Kiwoong; Lee, Yong-Ho; Kwon, Hyukchan; Park, Yongki; Pak, Hui-Nam; Ko, Young-Guk; Lee, Moonhyoung

    2016-01-01

    Purpose Magnetocardiography (MCG) has been proposed as a noninvasive, diagnostic tool for risk-stratifying patients with acute myocardial infarction (AMI). This study evaluated whether MCG predicts long-term prognosis in AMI. Materials and Methods In 124 AMI patients (95 males, mean age 60±11 years), including 39 with ST-elevation myocardial infarction, a 64-channel MCG was performed within 2 days after AMI. During a mean follow-up period of 6.1 years, major adverse cardiac events (MACE) were evaluated. Results MACE occurred in 31 (25%) patients, including 20 revascularizations, 8 deaths, and 3 re-infarctions. Non-dipole patterns were observed at the end of the T wave in every patients. However, they were observed at T-peak in 77% (24/31) and 54% (50/93) of patients with and without MACE, respectively (p=0.03). Maximum current, field map angles, and distance dynamics were not different between groups. In the multivariate analysis, patients with non-dipole patterns at T-peak had increased age- and gender-adjusted hazard ratios for MACE (hazard ratio 2.89, 95% confidence interval 1.20–6.97, p=0.02) and lower cumulative MACE-free survival than those with dipole patterns (p=0.02). Conclusion Non-dipole patterns at T-peak were more frequently observed in patients with MACE and were related to poor long-term prognosis. Thus, repolarization heterogeneity measured by MCG may be a useful predictor for AMI prognosis. PMID:27593860

  3. Coronary artery calcifications predict long term cardiovascular events in non diabetic Caucasian hemodialysis patients

    PubMed Central

    Noce, Annalisa; Canale, Maria Paola; Capria, Ambrogio; Rovella, Valentina; Tesauro, Manfredi; Splendiani, Giorgio; Annicchiarico-Petruzzelli, Margherita; Manzuoli, Micol; Simonetti, Giovanni; Di Daniele, Nicola

    2015-01-01

    Vascular calcifications are frequent in chronic renal disease and are associated to significant cardiovascular morbidity and mortality. The long term predictive value of coronary artery calcifications detected by multi-layer spiral computed tomography for major cardiovascular events was evaluated in non-diabetic Caucasian patients on maintenance hemodialysis free of clinical cardiovascular disease. Two-hundred and five patients on maintenance hemodialysis were enrolled into this observational, prospective cohort study. Patients underwent a single cardiac multi-layer spiral computed tomography. Calcium load was quantified and patients grouped according to the Agatston score: group 1 (Agatston score: 0), group 2 (Agatston score 1-400), group 3 (Agatston score 401-1000) and group 4 (Agatston score >1000). Follow-up was longer than seven years. Primary endpoint was death from a major cardiovascular event. Actuarial survival was calculated separately in the four groups with Kaplan-Meier method. Patients who died from causes other than cardiovascular disease and transplanted patients were censored. The “log rank” test was employed to compare survival curves. One-hundred two patients (49.7%) died for a major cardiovascular event during the follow-up period. Seven-year actuarial survival was more than 90% for groups 1 and 2, but failed to about 50% for group 3 and to <10% for group 4. Hence, Agatston score >400 predicts a significantly higher cardiovascular mortality compared with Agatston score <400 (p<0.0001); furthermore, serum Parathyroid hormone levels > 300 pg/l were associated to a lower survival (p < 0.05). Extended coronary artery calcifications detected by cardiac multi-layer spiral computed tomography, strongly predicted long term cardiovascular mortality in non-diabetic Caucasian patients on maintenance hemodialysis. Moreover, it was not related to conventional indices of atherosclerosis, but to other non-traditional risk factors, as serum Parathyroid

  4. Ordinary kriging approach to predicting long-term particulate matter concentrations in seven major Korean cities

    PubMed Central

    Kim, Sun-Young; Yi, Seon-Ju; Eum, Young Seob; Choi, Hae-Jin; Shin, Hyesop; Ryou, Hyoung Gon; Kim, Ho

    2014-01-01

    Objectives Cohort studies of associations between air pollution and health have used exposure prediction approaches to estimate individual-level concentrations. A common prediction method used in Korean cohort studies is ordinary kriging. In this study, performance of ordinary kriging models for long-term particulate matter less than or equal to 10 μm in diameter (PM10) concentrations in seven major Korean cities was investigated with a focus on spatial prediction ability. Methods We obtained hourly PM10 data for 2010 at 226 urban-ambient monitoring sites in South Korea and computed annual average PM10 concentrations at each site. Given the annual averages, we developed ordinary kriging prediction models for each of the seven major cities and for the entire country by using an exponential covariance reference model and a maximum likelihood estimation method. For model evaluation, cross-validation was performed and mean square error and R-squared (R2) statistics were computed. Results Mean annual average PM10 concentrations in the seven major cities ranged between 45.5 and 66.0 μg/m3 (standard deviation=2.40 and 9.51 μg/m3, respectively). Cross-validated R2 values in Seoul and Busan were 0.31 and 0.23, respectively, whereas the other five cities had R2 values of zero. The national model produced a higher crossvalidated R2 (0.36) than those for the city-specific models. Conclusions In general, the ordinary kriging models performed poorly for the seven major cities and the entire country of South Korea, but the model performance was better in the national model. To improve model performance, future studies should examine different prediction approaches that incorporate PM10 source characteristics. PMID:25262773

  5. Elevated Omentin Serum Levels Predict Long-Term Survival in Critically Ill Patients

    PubMed Central

    Luedde, Mark; Benz, Fabian; Niedeggen, Jennifer; Vucur, Mihael; Hippe, Hans-Joerg; Spehlmann, Martina E.; Schueller, Florian; Loosen, Sven; Frey, Norbert; Trautwein, Christian; Koch, Alexander; Luedde, Tom; Tacke, Frank

    2016-01-01

    Introduction. Omentin, a recently described adipokine, was shown to be involved in the pathophysiology of inflammatory and infectious diseases. However, its role in critical illness and sepsis is currently unknown. Materials and Methods. Omentin serum concentrations were measured in 117 ICU-patients (84 with septic and 33 with nonseptic disease etiology) admitted to the medical ICU. Results were compared with 50 healthy controls. Results. Omentin serum levels of critically ill patients at admission to the ICU or after 72 hours of ICU treatment were similar compared to healthy controls. Moreover, circulating omentin levels were independent of sepsis and etiology of critical illness. Notably, serum concentrations of omentin could not be linked to concentrations of inflammatory cytokines or routinely used sepsis markers. While serum levels of omentin were not predictive for short term survival during ICU treatment, low omentin concentrations were an independent predictor of patients' overall survival. Omentin levels strongly correlated with that of other adipokines (e.g., leptin receptor or adiponectin), which have also been identified as prognostic markers in critical illness. Conclusions. Although circulating omentin levels did not differ between ICU-patients and controls, elevated omentin levels were predictive for an impaired patients' long term survival. PMID:27867249

  6. Preschool speech intelligibility and vocabulary skills predict long-term speech and language outcomes following cochlear implantation in early childhood.

    PubMed

    Castellanos, Irina; Kronenberger, William G; Beer, Jessica; Henning, Shirley C; Colson, Bethany G; Pisoni, David B

    2014-07-01

    Speech and language measures during grade school predict adolescent speech-language outcomes in children who receive cochlear implants (CIs), but no research has examined whether speech and language functioning at even younger ages is predictive of long-term outcomes in this population. The purpose of this study was to examine whether early preschool measures of speech and language performance predict speech-language functioning in long-term users of CIs. Early measures of speech intelligibility and receptive vocabulary (obtained during preschool ages of 3-6 years) in a sample of 35 prelingually deaf, early-implanted children predicted speech perception, language, and verbal working memory skills up to 18 years later. Age of onset of deafness and age at implantation added additional variance to preschool speech intelligibility in predicting some long-term outcome scores, but the relationship between preschool speech-language skills and later speech-language outcomes was not significantly attenuated by the addition of these hearing history variables. These findings suggest that speech and language development during the preschool years is predictive of long-term speech and language functioning in early-implanted, prelingually deaf children. As a result, measures of speech-language functioning at preschool ages can be used to identify and adjust interventions for very young CI users who may be at long-term risk for suboptimal speech and language outcomes.

  7. Lesion Load May Predict Long-Term Cognitive Dysfunction in Multiple Sclerosis Patients

    PubMed Central

    Lavorgna, Luigi; Messina, Silvia; Chisari, Clara Grazia; Ippolito, Domenico; Lanzillo, Roberta; Vacchiano, Veria; Realmuto, Sabrina; Valentino, Paola; Coniglio, Gabriella; Buccafusca, Maria; Paolicelli, Damiano; D’Ambrosio, Alessandro; Montella, Patrizia; Brescia Morra, Vincenzo; Savettieri, Giovanni; Alfano, Bruno; Gallo, Antonio; Simone, Isabella; Viterbo, Rosa; Zappia, Mario; Bonavita, Simona; Tedeschi, Gioacchino

    2015-01-01

    Background Magnetic Resonance Imaging (MRI) techniques provided evidences into the understanding of cognitive impairment (CIm) in Multiple Sclerosis (MS). Objectives To investigate the role of white matter (WM) and gray matter (GM) in predicting long-term CIm in a cohort of MS patients. Methods 303 out of 597 patients participating in a previous multicenter clinical-MRI study were enrolled (49.4% were lost at follow-up). The following MRI parameters, expressed as fraction (f) of intracranial volume, were evaluated: cerebrospinal fluid (CSF-f), WM-f, GM-f and abnormal WM (AWM-f), a measure of lesion load. Nine years later, cognitive status was assessed in 241 patients using the Symbol Digit Modalities Test (SDMT), the Semantically Related Word List Test (SRWL), the Modified Card Sorting Test (MCST), and the Paced Auditory Serial Addition Test (PASAT). In particular, being SRWL a memory test, both immediate recall and delayed recall were evaluated. MCST scoring was calculated based on the number of categories, number of perseverative and non-perseverative errors. Results AWM-f was predictive of an impaired performance 9 years ahead in SDMT (OR 1.49, CI 1.12–1.97 p = 0.006), PASAT (OR 1.43, CI 1.14–1.80 p = 0.002), SRWL-immediate recall (OR 1.72 CI 1.35–2.20 p<0.001), SRWL-delayed recall (OR 1.61 CI 1.28–2.03 p<0.001), MCST-category (OR 1.52, CI 1.2–1.9 p<0.001), MCST-perseverative error(OR 1.51 CI 1.2–1.9 p = 0.001), MCST-non perseverative error (OR 1.26 CI 1.02–1.55 p = 0.032). Conclusion In our large MS cohort, focal WM damage appeared to be the most relevant predictor of the long-term cognitive outcome. PMID:25816303

  8. Creep studies for zircaloy life prediction in water reactors

    NASA Astrophysics Data System (ADS)

    Murty, K. Linga

    1999-10-01

    Zirconium alloys, commonly used as cladding tubes in water reactors, undergo complex biaxial creep deformation. The anisotropic nature of these metals makes it relatively complex to predict their dimensional changes in-reactor. These alloys exhibit transients in creep mechanisms as stress levels change. The underlying creep mechanisms and creep anisotropy depend on the alloy composition as well as the thermomechanical treatment. The anisotropic biaxial creep of cold-worked and recrystallized Zircaloy-4 in terms of Hill’s generalized stress formulation is described, and the temperature and stress dependencies of the steady-state creep rate are reviewed. Predictive models that incorporate anelastic strain are used for transient and transients in creep.

  9. BRAF mutation is not predictive of long-term outcome in papillary thyroid carcinoma

    PubMed Central

    Henke, Lauren E; Pfeifer, John D; Ma, Changquing; Perkins, Stephanie M; DeWees, Todd; El-Mofty, Samir; Moley, Jeffrey F; Nussenbaum, Brian; Haughey, Bruce H; Baranski, Thomas J; Schwarz, Julie K; Grigsby, Perry W

    2015-01-01

    The BRAF mutation occurs commonly in papillary thyroid carcinoma (PTC). Previous investigations of its utility to predict recurrence-free survival (RFS) and disease-specific survival (DSS) have reported conflicting results and its role remains unclear. The purpose of this retrospective study was to determine the incidence of the BRAF mutation and analyze its relationship to clinicopathologic risk factors and long-term outcomes in the largest, single-institution American cohort to date. BRAF mutational status was determined in 508 PTC patients using RFLP analysis. The relationships between BRAF mutation status, patient and tumor characteristics, RFS, and DSS were analyzed. The BRAF mutation was present in 67% of patients. On multivariate analysis, presence of the mutation predicted only for capsular invasion (HR, 1.7; 95% CI, 1.1–2.6), cervical lymph node involvement (HR, 1.7; 95% CI, 1.1–2.7), and classic papillary histology (HR, 1.8; 95% CI 1.1–2.9). There was no significant relationship between the BRAF mutation and RFS or DSS, an observation that was consistent across univariate, multivariate, and Kaplan–Meier analyses. This is the most extensive study to date in the United States to demonstrate that BRAF mutation is of no predictive value for recurrence or survival in PTC. We found correlations of BRAF status and several clinicopathologic characteristics of high-risk disease, but limited evidence that the mutation correlates with more extensive or aggressive disease. This analysis suggests that BRAF is minimally prognostic in PTC. However, prevalence of the BRAF mutation is 70% in the general population, providing the opportunity for targeted therapy. PMID:25712893

  10. BRAF mutation is not predictive of long-term outcome in papillary thyroid carcinoma.

    PubMed

    Henke, Lauren E; Pfeifer, John D; Ma, Changquing; Perkins, Stephanie M; DeWees, Todd; El-Mofty, Samir; Moley, Jeffrey F; Nussenbaum, Brian; Haughey, Bruce H; Baranski, Thomas J; Schwarz, Julie K; Grigsby, Perry W

    2015-06-01

    The BRAF mutation occurs commonly in papillary thyroid carcinoma (PTC). Previous investigations of its utility to predict recurrence-free survival (RFS) and disease-specific survival (DSS) have reported conflicting results and its role remains unclear. The purpose of this retrospective study was to determine the incidence of the BRAF mutation and analyze its relationship to clinicopathologic risk factors and long-term outcomes in the largest, single-institution American cohort to date. BRAF mutational status was determined in 508 PTC patients using RFLP analysis. The relationships between BRAF mutation status, patient and tumor characteristics, RFS, and DSS were analyzed. The BRAF mutation was present in 67% of patients. On multivariate analysis, presence of the mutation predicted only for capsular invasion (HR, 1.7; 95% CI, 1.1-2.6), cervical lymph node involvement (HR, 1.7; 95% CI, 1.1-2.7), and classic papillary histology (HR, 1.8; 95% CI 1.1-2.9). There was no significant relationship between the BRAF mutation and RFS or DSS, an observation that was consistent across univariate, multivariate, and Kaplan-Meier analyses. This is the most extensive study to date in the United States to demonstrate that BRAF mutation is of no predictive value for recurrence or survival in PTC. We found correlations of BRAF status and several clinicopathologic characteristics of high-risk disease, but limited evidence that the mutation correlates with more extensive or aggressive disease. This analysis suggests that BRAF is minimally prognostic in PTC. However, prevalence of the BRAF mutation is 70% in the general population, providing the opportunity for targeted therapy.

  11. Predicting Agricultural Management Influence on Long-Term Soil Organic Carbon Dynamics: Implications for Biofuel Production

    SciTech Connect

    Gollany, H. T.; Rickman, R. W.; Albrecht, S. L.; Liang, Y.; Kang, Shujiang; Machado, S.

    2011-01-01

    Long-term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no-tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2- or 3-yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1 19 C), precipitation (402 973 mm), and SOC (5.89 33.58 g SOC kg 1) at the LTE sites were significantly related (r 2 = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks

  12. Prediction of long-term erosion from landfill covers in the southwest

    SciTech Connect

    Anderson, C.E.; Stormont, J.C.

    1997-12-31

    Erosion is a primary stressor of landfill covers, especially for climates with high intensity storms and low native plant density. Rills and gullies formed by discrete events can damage barrier layers and induce failure. Geomorphologic, empirical and physical modeling procedures are available to provide estimates of surface erosion, but numerical modeling requires accurate representation of the severe rainfall events that generate erosion. The National Weather Service precipitation frequency data and estimates of 5, 10, 15, 30 and 60-minute intensity can be statistically combined in a numerical model to obtain long-term erosion estimates. Physically based numerical models using the KINEROS and AHYMO programs have been utilized to predict the erosion from a southwestern landfill or waste containment site with 0.03, 0.05 and 0.08 meter per meter surface slopes. Results of AHYMO modeling were within 15 percent of average annual values computed with the empirical Universal Soil Loss Equation. However, the estimation of rill and gully formation that primarily degrades cover systems requires quantifying single events. For Southwestern conditions, a single 10-year storm can produce erosion quantifies equal to three times the average annual erosion and a 100-year storm can produce five times the average annual erosion.

  13. The applicability of semi-analytical method for different orbits in long term prediction

    NASA Astrophysics Data System (ADS)

    Wang, Dawei; Tang, Jingshi; Liu, Lin

    2016-07-01

    To understand the long-term evolution and distribution of the space objects, it is necessary to propagate the orbits of respective objects. Compared with the short-term prediction of a few days, the priority concerns are the accuracy of major orbital elements including the semi-major axis and eccentricity which define the shape of the orbit, the orbital inclination and the right ascension of the ascending node which define the orientation of the orbit, as well as the calculation speed. Given such requirement, it is preferable to adopt the semi-analytical method, which averages the system over the orbital period, and integrates the averaged system using the numerical method. However, throughout available literatures, it is rarely seen that the semi-analytical methods are quantitatively assessed regarding the accuracy when applied to various types of orbits. In this paper, we would like to report our implementation and assessment of the semi-analytical method. The quantitative assessment covers the commonly used orbits for Earth satellites. In some rare special cases where the performance of our method appears abnormal, we discuss the reasons and possible solutions.

  14. Latent profiles of nonresidential father engagement six years after divorce predict long-term offspring outcomes.

    PubMed

    Modecki, Kathryn Lynn; Hagan, Melissa J; Sandler, Irwin; Wolchik, Sharlene A

    2015-01-01

    This study examined profiles of nonresidential father engagement (i.e., support to the adolescent, contact frequency, remarriage, relocation, and interparental conflict) with their adolescent children (N = 156) 6 to 8 years following divorce and the prospective relation between these profiles and the psychosocial functioning of their offspring, 9 years later. Parental divorce occurred during late childhood to early adolescence; indicators of nonresidential father engagement were assessed during adolescence, and mental health problems and academic achievement of offspring were assessed 9 years later in young adulthood. Three profiles of father engagement were identified in our sample of mainly White, non-Hispanic divorced fathers: Moderate Involvement/Low Conflict, Low Involvement/Moderate Conflict, and High Involvement/High Conflict. Profiles differentially predicted offspring outcomes 9 years later when they were young adults, controlling for quality of the mother-adolescent relationship, mother's remarriage, mother's income, and gender, age, and offspring mental health problems in adolescence. Offspring of fathers characterized as Moderate Involvement/Low Conflict had the highest academic achievement and the lowest number of externalizing problems 9 years later compared to offspring whose fathers had profiles indicating either the highest or lowest levels of involvement but higher levels of conflict. Results indicate that greater paternal psychosocial support and more frequent father-adolescent contact do not outweigh the negative impact of interparental conflict on youth outcomes in the long term. Implications of findings for policy and intervention are discussed.

  15. Long-term irradiance observation and short-term flare prediction with LYRA on PROBA2

    NASA Astrophysics Data System (ADS)

    Dammasch, Ingolf; Dominique, Marie; West, Matthew; Katsiyannis, Thanassis; Ryan, Daniel; Wauters, Laurence

    The solar radiometer LYRA on board the ESA micro-satellite PROBA2 has observed the Sun continuously since January 2010 in various spectral band passes, and has gained a considerable data base. Two of the LYRA channels cover the irradiance between soft X-ray and extreme ultraviolet. The variation of the sunspot number appears to show a strong similarity with the variation of these channels, when their long-range development is taken into account. The same holds for SXR levels observed by the GOES satellites. Due to LYRA's bandwidth and coverage of various active-region temperatures, its relatively smooth development may yield some information on the structure of the current solar cycle. On its websites, LYRA presents not only EUV and SXR time series in near real-time, but also information on flare parameters and long-term irradiance and sunspot levels. It will be demonstrated whether it is possible to aid space weather forecast with these statistical data, especially for the prediction of expected flare strength on a daily basis.

  16. Glycated Albumin Predicts Long-term Survival in Patients Undergoing Hemodialysis

    PubMed Central

    Lu, Chien-Lin; Ma, Wen-Ya; Lin, Yuh-Feng; Shyu, Jia-Fwu; Wang, Yuan-Hung; Liu, Yueh-Min; Wu, Chia-Chao; Lu, Kuo-Cheng

    2016-01-01

    Background: In patients with advanced renal dysfunction undergoing maintenance hemodialysis, glycated albumin (GA) levels may be more representative of blood glucose levels than hemoglobin A1C levels. The aim of this study was to determine the predictive power of GA levels on long-term survival in hemodialysis patients. Methods: A total of 176 patients with a mean age of 68.2 years were enrolled. The median duration of follow-up was 51.0 months. Receiver-operating characteristic curve analysis was utilized to determine the optimal cutoff value. We examined the cumulative survival rate by Kaplan-Meier estimates and the influence of known survival factors with the multivariate Cox proportional-hazard regression model. Results: In the whole patient group, cumulative survival in the low GA group was better than in the high GA group (p=0.030), with more prominence in those aged <70 years (p=0.029). In subgroup analysis, both diabetic (DM) and non-DM patients with low GA had a better cumulative survival compared with those with high GA. The risk of mortality increased by 3.0% for each 1% increase in serum GA level in all patients undergoing hemodialysis. Conclusions: In addition to serving as a glycemic control marker, GA levels may be useful for evaluating the risk of death in both DM and non-DM patients on hemodialysis. PMID:27226780

  17. Predicting long-term carbon mineralization and trace gas production from thawing permafrost of Northeast Siberia.

    PubMed

    Knoblauch, Christian; Beer, Christian; Sosnin, Alexander; Wagner, Dirk; Pfeiffer, Eva-Maria

    2013-04-01

    The currently observed Arctic warming will increase permafrost degradation followed by mineralization of formerly frozen organic matter to carbon dioxide (CO2 ) and methane (CH4 ). Despite increasing awareness of permafrost carbon vulnerability, the potential long-term formation of trace gases from thawing permafrost remains unclear. The objective of the current study is to quantify the potential long-term release of trace gases from permafrost organic matter. Therefore, Holocene and Pleistocene permafrost deposits were sampled in the Lena River Delta, Northeast Siberia. The sampled permafrost contained between 0.6% and 12.4% organic carbon. CO2 and CH4 production was measured for 1200 days in aerobic and anaerobic incubations at 4 °C. The derived fluxes were used to estimate parameters of a two pool carbon degradation model. Total CO2 production was similar in Holocene permafrost (1.3 ± 0.8 mg CO2 -C gdw(-1) aerobically, 0.25 ± 0.13 mg CO2 -C gdw(-1) anaerobically) as in 34 000-42 000-year-old Pleistocene permafrost (1.6 ± 1.2 mg CO2 -C gdw(-1) aerobically, 0.26 ± 0.10 mg CO2 -C gdw(-1) anaerobically). The main predictor for carbon mineralization was the content of organic matter. Anaerobic conditions strongly reduced carbon mineralization since only 25% of aerobically mineralized carbon was released as CO2 and CH4 in the absence of oxygen. CH4 production was low or absent in most of the Pleistocene permafrost and always started after a significant delay. After 1200 days on average 3.1% of initial carbon was mineralized to CO2 under aerobic conditions while without oxygen 0.55% were released as CO2 and 0.28% as CH4 . The calibrated carbon degradation model predicted cumulative CO2 production over a period of 100 years accounting for 15.1% (aerobic) and 1.8% (anaerobic) of initial organic carbon, which is significantly less than recent estimates. The multiyear time series from the incubation experiments helps to more reliably constrain projections of future

  18. Pre-surgery Disability Compensation Predicts Long-Term Disability among Workers with Carpal Tunnel Syndrome

    PubMed Central

    Spector, June T.; Turner, Judith A.; Fulton-Kehoe, Deborah; Franklin, Gary

    2012-01-01

    Background We sought to identify early risk factors for work disability compensation prior to and after carpal tunnel syndrome (CTS) surgery, and to determine whether pre-surgery disability compensation is associated with long-term disability. Methods Washington State workers’ compensation administrative data and data from interviews with workers 18 days (median) after submitting new workers’ compensation claims for CTS were examined. Baseline risk factors for pre-surgery disability compensation and for long-term disability (≥365 days of work disability compensation prior to two years after claim filing) were evaluated for workers who underwent CTS surgery and had at least one day of disability compensation (N=670). Results After adjustment for baseline long-term disability risk factors, workers with pre-surgery disability compensation had over five times the odds of long-term disability. Baseline factors in multiple domains, including job, psychosocial, clinical, and worker pain and function, were associated with both pre-surgery disability compensation and long-term disability. Conclusions Risk factors for work disability prior to and after CTS surgery are similar, and early work disability is a risk factor for long-term CTS-related disability. An integrated approach to CTS-related disability prevention could include identifying and addressing combined risk factors soon after claim filing, more efficient use of conservative treatments and appropriate work modifications to minimize early work loss, and, when indicated, timely surgical intervention. PMID:22392804

  19. Long-term predictability of regions and dates of strong earthquakes

    NASA Astrophysics Data System (ADS)

    Kubyshen, Alexander; Doda, Leonid; Shopin, Sergey

    2016-04-01

    Results on the long-term predictability of strong earthquakes are discussed. It is shown that dates of earthquakes with M>5.5 could be determined in advance of several months before the event. The magnitude and the region of approaching earthquake could be specified in the time-frame of a month before the event. Determination of number of M6+ earthquakes, which are expected to occur during the analyzed year, is performed using the special sequence diagram of seismic activity for the century time frame. Date analysis could be performed with advance of 15-20 years. Data is verified by a monthly sequence diagram of seismic activity. The number of strong earthquakes expected to occur in the analyzed month is determined by several methods having a different prediction horizon. Determination of days of potential earthquakes with M5.5+ is performed using astronomical data. Earthquakes occur on days of oppositions of Solar System planets (arranged in a single line). At that, the strongest earthquakes occur under the location of vector "Sun-Solar System barycenter" in the ecliptic plane. Details of this astronomical multivariate indicator still require further research, but it's practical significant is confirmed by practice. Another one empirical indicator of approaching earthquake M6+ is a synchronous variation of meteorological parameters: abrupt decreasing of minimal daily temperature, increasing of relative humidity, abrupt change of atmospheric pressure (RAMES method). Time difference of predicted and actual date is no more than one day. This indicator is registered 104 days before the earthquake, so it was called as Harmonic 104 or H-104. This fact looks paradoxical, but the works of A. Sytinskiy and V. Bokov on the correlation of global atmospheric circulation and seismic events give a physical basis for this empirical fact. Also, 104 days is a quarter of a Chandler period so this fact gives insight on the correlation between the anomalies of Earth orientation

  20. Early Prediction of Long-Term Response to Cabergoline in Patients with Macroprolactinomas

    PubMed Central

    Lee, Youngki; Ku, Cheol Ryong; Kim, Eui-Hyun; Lee, Eun Jig; Kim, Sun Ho

    2014-01-01

    Background Cabergoline is typically effective for treating prolactinomas; however, some patients display cabergoline resistance, and the early characteristics of these patients remain unclear. We analyzed early indicators predicting long-term response to cabergoline. Methods We retrospectively reviewed the cases of 44 patients with macroprolactinomas who received cabergoline as first-line treatment; the patients were followed for a median of 16 months. The influence of various clinical parameters on outcomes was evaluated. Results Forty patients (90.9%) were treated medically and displayed tumor volume reduction (TVR) of 74.7%, a prolactin normalization (NP) rate of 81.8%, and a complete response (CR; TVR >50% with NP, without surgery) rate of 70.5%. Most patients (93.1%) with TVR ≥25% and NP at 3 months eventually achieved CR, whereas only 50% of patients with TVR ≥25% without NP and no patients with TVR <25% achieved CR. TVR at 3 months was strongly correlated with final TVR (R=0.785). Patients with large macroadenomas exhibited a low NP rate at 3 months, but eventually achieved TVR and NP rates similar to those of patients with smaller tumors. Surgery independently reduced the final dose of cabergoline (β=-1.181 mg/week), and two of four patients who underwent surgery were able to discontinue cabergoline. Conclusion Determining cabergoline response using TVR and NP 3 months after treatment is useful for predicting later outcomes. However, further cabergoline administration should be considered for patients with TVR >25% at 3 months without NP, particularly those with huge prolactinomas, because a delayed response may be achieved. As surgery can reduce the cabergoline dose necessary for successful disease control, it should be considered for cabergoline-resistant patients. PMID:25309786

  1. Short Term Weather Forecasting and Long Term Climate Predictions in Mesoamerica

    NASA Astrophysics Data System (ADS)

    Hardin, D. M.; Daniel, I.; Mecikalski, J.; Graves, S.

    2008-05-01

    The SERVIR project utilizes several predictive models to support regional monitoring and decision support in Mesoamerica. Short term forecasts ranging from a few hours to several days produce more than 30 data products that are used daily by decision makers, as well as news organizations in the region. The forecast products can be visualized in both two and three dimensional viewers such as Google Maps and Google Earth. Other viewers developed specifically for the Mesoamerican region by the University of Alabama in Huntsville and the Institute for the Application of Geospatial Technologies in Auburn New York can also be employed. In collaboration with the NASA Short Term Prediction Research and Transition (SpoRT) Center SERVIR utilizes the Weather Research and Forecast (WRF) model to produce short-term (24 hr) regional weather forecasts twice a day. Temperature, precipitation, wind, and other variables are forecast in 10km and 30km grids over the Mesoamerica region. Using the PSU/NCAR Mesoscale Model, known as MM5, SERVIR produces 48 hour- forecasts of soil temperature, two meter surface temperature, three hour accumulated precipitation, winds at different heights, and other variables. These are forecast hourly in 9km grids. Working in collaboration with the Atmospheric Science Department of the University of Alabama in Huntsville produces a suite of short-term (0-6 hour) weather prediction products are generated. These "convective initiation" products predict the onset of thunderstorm rainfall and lightning within a 1-hour timeframe. Models are also employed for long term predictions. The SERVIR project, under USAID funding, has developed comprehensive regional climate change scenarios of Mesoamerica for future years: 2010, 2015, 2025, 2050, and 2099. These scenarios were created using the Pennsylvania State University/National Center for Atmospheric Research (MM5) model and processed on the Oak Ridge National Laboratory Cheetah supercomputer. The goal of these

  2. Contextual exploration previous to an aversive event predicts long-term emotional consequences of severe stress

    PubMed Central

    Girardi, Carlos E. N.; Tiba, Paula A.; Llobet, Gisela B.; Levin, Raquel; Abilio, Vanessa C.; Suchecki, Deborah

    2013-01-01

    Traumatic stress can lead to long-term emotional alterations, which may result in Posttraumatic Stress Disorder (PTSD). Fear reactions triggered by conditioned cues and exacerbated emotional arousal in face of non-conditioned stimuli are among the most prominent features of PTSD. We hypothesized that long-term emotional alterations seen in PTSD may depend on the strength of context-trauma association. Here, we investigated the contribution of previous contextual exploration to the long-term emotional outcomes of an intense foot shock in rats. We exposed male Wistar rats to a highly stressful event (foot shock, 2 mA, 1 sec) allowing them to explore or not the chamber prior to trauma. We, then, evaluated the long-term effects on emotionality. Fear was assessed by the time spent in freezing behavior either upon re-exposure to trauma context or upon exposure to an unknown environment made potentially more aversive by presentation of an acoustic stimulus. Behaviors on the elevated-plus-maze and acoustic startle response were also assessed. The possibility to explore the environment immediately before the aversive event led to differential long-term emotional effects, including a heightened freezing response to re-exposure to context, blunted exploratory behavior, fear sensitization and exacerbation of the acoustic startle response, in contrast to the minor outcomes of the foot shock with no prior context exploration. The data showed the strong contribution of contextual learning to long-term behavioral effects of traumatic stress. We argue that contextual representation contributes to the robust long-term behavioral alterations seen in this model of traumatic stress. PMID:24106466

  3. Assessing the long-term species composition predicted by PrognAus

    PubMed Central

    Huber, Markus O.

    2010-01-01

    Tree growth models are supposed to contain stand growth laws as so called “emergent properties” which derive from interactions of individual-tree growth and mortality functions. This study investigates whether the evolving tree species composition in a long term simulation by the distance-independent tree growth model PrognAus matches the species composition of the potential natural vegetation type which is expected to occur if one refrains from further management interventions and major disturbances, climate change, and changes in site conditions can be excluded. For this purpose the development of 6933 sample plots of the Austrian National Forest Inventory was predicted for 2500 years. The resulting species proportions, derived from volume per hectare of 15 tree species or species groups, were used to classify every sample plot according to potential natural forest types, following a classification scheme based on expert knowledge. These simulated potential natural vegetation types were compared with expert reconstructions of the sample plots of the Austrian National Forest Inventory. A total of 5789 plots were actually classified with the scheme; in 33% of the cases the classification on the basis of the PrognAus-simulations was identical with the classification by the Austrian National Forest Inventory. A predominantly correct classification was achieved for the subalpine Picea abies-type and the Fagus sylvatica-type although PrognAus showed a tendency to overestimate the proportion of F. sylvatica and P. abies. Weaknesses in the ability to simulate forest types dominated by Quercus spp., Acer spp., and Pinus sylvestris were identified. This shortcoming might be caused by the mortality model which allows a larger diameter at breast height for F. sylvatica or by the ingrowth model whose terms for the consideration of inter-specific competition may lead to a disadvantage of Quercus spp., P. sylvestris, and Abies alba. Moreover, the ingrowth model might be

  4. Clinical Score Predicting Long-Term Survival after Repeat Resection for Recurrent Adrenocortical Carcinoma

    PubMed Central

    Tran, Thuy B; Maithel, Shishir K; Pawlik, Timothy M; Wang, Tracy S; Hatzaras, Ioannis; Phay, John E; Fields, Ryan C; Weber, Sharon M; Sicklick, Jason K; Yopp, Adam C; Duh, Quan-Yang; Solorzano, Carmen C; Votanopoulos, Konstantinos I; Poultsides, George A

    2017-01-01

    BACKGROUND Adrenocortical carcinoma (ACC) is an aggressive malignancy typically resistant to chemotherapy and radiation. Surgery, even in the setting of locally recurrent or metastatic disease, remains the only potentially curative option. However, the subset of patients who will benefit from repeat resection in this setting remains ill defined. The objective of this study was to propose a prognostic clinical score that facilitates selection of patients for repeat resection of recurrent ACC. STUDY DESIGN Patients who underwent curative-intent repeat resection for recurrent ACC at 1 of 13 academic medical centers participating in the US ACC Study Group were identified. End points included morbidity, mortality, and overall survival. RESULTS Fifty-six patients underwent repeat curative-intent resection for recurrent ACC (representing 21% of 265 patients who underwent resection for primary ACC) from 1997 to 2014. Median age was 52 years. Sites of resected recurrence included locoregional only (54%), lung only (14%), liver only (12%), combined locoregional and lung (4%), combined liver and lung (4%), and other distant sites (12%). Thirty-day morbidity and mortality rates were 40% and 5.4%, respectively. Cox regression analysis revealed that the presence of multifocal recurrence, disease-free interval <12 months, and extrapulmonary distant metastases were independent predictors of poor survival. A clinical score consisting of 1-point each for the 3 variables demonstrated good discrimination in predicting survival after repeat resection (5-year: 72% for 0 points, 32% for 1 point, 0% for 2 or 3 points; p = 0.0006, area under the curve = 0.78). CONCLUSIONS Long-term survival after repeat resection for recurrent ACC is feasible when 2 of the following factors are present: solitary tumor, disease-free interval >12 months, and locoregional or pulmonary recurrence. PMID:27618748

  5. Near and long-term load prediction using radial basis function networks

    SciTech Connect

    Hancock, M.F.

    1995-12-31

    A number of researchers have investigated the application of multi-layer perceptrons (MLP`s), a variety of neural network, to the problem of short-term load forecasting for electric utilities (e.g., Rahman & Hazin, IEEE Trans. Power Systems, May 1993). {open_quotes}Short-term{close_quotes} in this context typically means {open_quotes}next day{close_quotes}. These forecasts have been based upon previous day actual loads and meteorological factors (e.g., max-min temperature, relative humidity). We describe the application of radial basis function networks (RBF`s) to the {open_quotes}long-term{close_quotes} (next year) load forecasting problem. The RBF network performs a two-stage classification based upon annual average loads and meteorological data. During stage 1, discrete classification is performed using radius-limited elements. During stage 2, a multi-layer perceptron may be applied. The quantized output is used to correct a prediction template. The stage 1 classifier is trained by maximizing an objective function (the {open_quotes}disambiguity{close_quotes}). The stage 2 MLP`s are trained by standard back-propagation. This work uses 12 months of hourly meteorological data, and the corresponding hourly load data for both commercial and residential feeders. At the current stage of development, the RBF machine can train on 20% of the weather/load data (selected by simple linear sampling), and estimate the hourly load for an entire year (8,760 data points) with 9.1% error (RMS, relative to daily peak load). (By comparison, monthly mean profiles perform at c. 12% error.) The best short-term load forecasters operate in the 2% error range. The current system is an engineering prototype, and development is continuing.

  6. Greater emotional arousal predicts poorer long-term memory of communication skills in couples.

    PubMed

    Baucom, Brian R; Weusthoff, Sarah; Atkins, David C; Hahlweg, Kurt

    2012-06-01

    Many studies have examined the importance of learning skills in behaviorally based couple interventions but none have examined predictors of long-term memory for skills. Associations between emotional arousal and long-term recall of communication skills delivered to couples during a behaviorally based relationship distress prevention program were examined in a sample of 49 German couples. Fundamental frequency (f(0)), a vocal measure of encoded emotional arousal, was measured during pre-treatment couple conflict. Higher levels of f(0) were linked to fewer skills remembered 11 years after completing the program, and women remembered more skills than men. Implications of results for behaviorally based couple interventions are discussed.

  7. Predictive factors for long-term outcome of anterior cervical decompression and fusion: a multivariate data analysis

    PubMed Central

    Peolsson, Michael

    2007-01-01

    We conducted a prospective randomized study to investigate predictive factors for short- and long-term outcome of anterior cervical decompression and fusion (ACDF) as measured by current pain intensity on the Visual Analogue Scale (VAS) and by disability using the Neck Disability Index (NDI). Current understanding about how preoperative and short-term outcome data predict long-term outcome is sparse, and there are few studies involving analysis of short-term follow-up using multivariate approaches with quantification of the relative importance of each variable studied. A total of 95 patients were randomly allocated for ACDF with the cervical intervertebral fusion cage or the Cloward procedure. The mean follow-up time was 19 months (range 12–24) for short-term follow-up and 76 months (range 56–94 months) for long-term. Background factors, radiologically detected findings, physiological measurements, treatment type, pain, and disability were used as potential predictors. Multivariate statistical analysis by projection to latent structures was used to investigate predictors of importance for short- and long-term outcome of ACDF. A “preoperative” low disability and pain intensity, non-smoking status, male sex, good hand strength, and an active range of motion (AROM) in the neck were significant predictors for good short- and long-term outcomes. The short-term outcome data were better at predicting long-term outcome than were baseline data. Radiologically detected findings and surgical technique used were mainly insignificant as predictors. We suggest that the inclusion criteria for ACDF should be based on a bio-psycho-social model including NDI. NDI may also be regarded as an important outcome measurement in evaluation of ACDF. PMID:18084782

  8. Officer Individual Differences: Predicting Long-Term Continuance and Performance in the U.S. Army

    DTIC Science & Technology

    2012-10-01

    200 words): This project investigated individual differences in knowledge, skills, abilities, and personality traits as contributors to long-term...of interest. In addition, these cognitively based selection tools may be supplemented with social, motivational, and personality measures. 15...PAGES 39 21. RESPONSIBLE PERSON 16. REPORT Unclassified 17. ABSTRACT Unclassified 18. THIS PAGE Unclassified (Name and

  9. Compartment model for long-term contamination prediction in deciduous fruit trees after a nuclear accident

    SciTech Connect

    Antonopoulos-Domis, M.; Clouvas, A.; Gagianas, A. )

    1990-06-01

    Radiocesium contamination from the Chernobyl accident of different parts (fruits, leaves, and shoots) of selected apricot trees in North Greece was systematically measured in 1987 and 1988. The results are presented and discussed in the framework of a simple compartment model describing the long-term contamination uptake mechanism of deciduous fruit trees after a nuclear accident.

  10. Predicting Long-Term Growth in Students' Mathematics Achievement: The Unique Contributions of Motivation and Cognitive Strategies

    ERIC Educational Resources Information Center

    Murayama, Kou; Pekrun, Reinhard; Lichtenfeld, Stephanie; vom Hofe, Rudolf

    2013-01-01

    This research examined how motivation (perceived control, intrinsic motivation, and extrinsic motivation), cognitive learning strategies (deep and surface strategies), and intelligence jointly predict long-term growth in students' mathematics achievement over 5 years. Using longitudinal data from six annual waves (Grades 5 through 10;…

  11. An analysis of precipitation occurrences in Los Alamos, New Mexico, for long-term predictions of waste repository behavior

    SciTech Connect

    Nyhan, J.; Beckman, R.; Bowen, B.

    1989-02-01

    This study describes precipitation as an uncontrolled natural input influencing the hydrology of waste repositories in terms of their ultimate long-term closure. The general climatology of the western states, including that of New Mexico and Los Alamos, is first described. An analysis of the precipitation patterns at Los Alamos is then presented to be used for predicting long-term precipitation occurrences and shallow land burial site behavior. The waste management implications of this precipitation analysis are then discussed and future meteorological research needs are identified. 13 refs., 10 figs., 2 tabs.

  12. Prediction of long-term properties in polymeric systems: I. Slow crack propagation in poly(vinyl chloride). II. Aging of poly(lactide)/poly(ethylene glycol) blends

    NASA Astrophysics Data System (ADS)

    Hu, Yu

    Slow crack growth in PVC pipe was studied in order to develop a methodology for predicting long-term creep fracture from short-term tension-tension fatigue tests. In all cases, the crack propagated continuously through a crack-tip craze. In fatigue, the density of drawn craze fibrils gradually increased with decreased frequency and increased temperature. At the lowest frequency, 0.01 Hz, the fibril density in fatigue approached that in creep. The kinetics of fatigue and creep crack growth followed the conventional Paris law formulations with the same power 2.7, da/dt = AfDK2.7I , da/dt = BK2.7I , respectively. The effects of frequency, temperature and R-ratio (the ratio of minimum to maximum stress intensity factor in the fatigue loading cycle) on the Paris law prefactors were characterized. A linear correlation allowed extrapolation of the creep prefactor ( B) from fatigue data. The extrapolated values were systematically higher than the values measured directly from creep and only converged at Tg. The difference was attributed to damage of the craze fibrils during crack closure upon unloading in the fatigue cycle. Blending poly(ethylene glycol) (PEG) with poly(lactide) (PLA) decreases the Tg and improves the mechanical properties. It was demonstrated that a PLA of lower stereoregularity was miscible with up to 30 wt% PEG. Aging was due to slow crystallization of PEG from the homogeneous amorphous blend. Crystallization of PEG depleted the amorphous phase of PEG and gradually increased the Tg until aging essentially ceased when Tg of the amorphous phase reached the aging temperature. Different aging mechanism was found with a crystallizable PLA of higher stereoregularity. The effect of cooling rate on crystallization and subsequent aging of high stereoregular PLA blended PEG was studied by thermal analysis and by direct observation of the solid state structure with atomic force microscopy (AFM). The partially crystallized blend obtained with a cooling rate of 30

  13. Predictable Unpredictability: the Problem with Basing Medicare Policy on Long-Term Financial Forecasting.

    PubMed

    Glied, Sherry; Zaylor, Abigail

    2015-07-01

    The authors assess how Medicare financing and projections of future costs have changed since 2000. They also assess the impact of legislative reforms on the sources and levels of financing and compare cost forecasts made at different times. Although the aging U.S. population and rising health care costs are expected to increase the share of gross domestic product devoted to Medicare, changes made in the program over the past decade have helped stabilize Medicare's financial outlook--even as benefits have been expanded. Long-term forecasting uncertainty should make policymakers and beneficiaries wary of dramatic changes to the program in the near term that are intended to alter its long-term forecast: the range of error associated with cost forecasts rises as the forecast window lengthens. Instead, policymakers should focus on the immediate policy window, taking steps to reduce the current burden of Medicare costs by containing spending today.

  14. Predictive capability of long-term cavitation and liquid impingement erosion models

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Buckley, D. H.

    1984-01-01

    A brief overview of long-term cavitation and liquid impingement erosion and modeling methods proposed by different investigators, including the curve-fit approach is presented. A table was prepared to highlight the number of variables necessary for each model in order to compute the erosion-versus-time curves. A power law relation based on the average erosion rate is suggested which may solve several modeling problems. Previously announced in STAR as N83-22386

  15. Computer program for predicting creep behavior of bodies of revolution

    NASA Technical Reports Server (NTRS)

    Adams, R.; Greenbaum, G.

    1971-01-01

    Computer program, CRAB, uses finite-element method to calculate creep behavior and predict steady-state stresses in an arbitrary body of revolution subjected to a time-dependent axisymmetric load. Creep strains follow a time hardening law and a Prandtl-Reuss stress-strain relationship.

  16. Systematic review: Evidence for Predictive Validity of Remission on Long Term Outcome in Rheumatoid Arthritis

    PubMed Central

    van Tuyl, Lilian HD; Felson, Prof David T; Wells, Prof George; Smolen, Prof Josef; Zhang, Dr Bin; Boers, Prof Maarten

    2010-01-01

    Objective Remission is rapidly becoming a key endpoint in rheumatoid arthritis clinical trials, but its definition is not satisfactory. Although it is generally believed that achieving a state of remission will lead to better structural outcome, this has not been studied systematically. As a part of an undertaking to redefine remission, the current review describes the relationship between remission and long term structural outcome. Methods A systematic literature search of PubMed, Embase.com, and the Cochrane Library intersected three groups of terms: rheumatoid arthritis, remission and long term outcome. The search identified 1138 records, of which 14 were relevant to the research question. Results All the studies included in this review showed a relationship between remission and long term structural damage or disability. Patients that achieved a state remission, defined in various ways, showed less deterioration of function and radiographic progression compared to patients who did not reach a state of remission. Conclusion Patients who achieve a state of remission are less likely to show deterioration of function and radiographic progression compared to patients that do not reach a state of remission. PMID:20191498

  17. Incremental validity of neuropsychological evaluations to computed tomography in predicting long-term outcomes after traumatic brain injury.

    PubMed

    Williams, Michael W; Rapport, Lisa J; Hanks, Robin A; Millis, Scott R; Greene, Hillary A

    2013-01-01

    This study evaluated the incremental utility of neuropsychological tests to computed tomography (CT) in predicting long-term outcomes of adults with moderate to severe traumatic brain injury (TBI). Participants were 288 adults with mild complicated, moderate, and severe TBI. Longitudinal data were evaluated during inpatient status in an urban rehabilitation hospital with a TBI Model System, as well as 1 and 2 years post injury. Predictors including demographic characteristics, injury severity, CT characteristics, and neuropsychological evaluations were regressed to outcomes of disability, life satisfaction, and employment at 1 and 2 years post injury. Prediction of life satisfaction was not improved with the use of CT characteristics or neuropsychological tests, but prediction of return to work was improved by these variables at 2 years post injury. Neuropsychological evaluations uniquely contributed to outcome predictions of functional disability, even after considering demographic and injury severity characteristics, including information from CT. In contrast, CT characteristics were not predictive of long-term functional disability at 1 or 2 years post TBI. Taken together, the findings indicate that neuropsychological tests add unique predictive information for long-term functional outcomes after TBI.

  18. Rationalization of Creep Data of Creep-Resistant Steels on the Basis of the New Power Law Creep Equation

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Yang, M.; Song, X. L.; Jia, J.; Xiang, Z. D.

    2016-07-01

    The conventional power law creep equation (Norton equation) relating the minimum creep rate to creep stress and temperature cannot be used to predict the long-term creep strengths of creep-resistant steels if its parameters are determined only from short-term measurements. This is because the stress exponent and activation energy of creep determined on the basis of this equation depend on creep temperature and stress and these dependences cannot be predicted using this equation. In this work, it is shown that these problems associated with the conventional power law creep equation can be resolved if the new power law equation is used to rationalize the creep data. The new power law creep equation takes a form similar to the conventional power law creep equation but has a radically different capability not only in rationalizing creep data but also in predicting the long-term creep strengths from short-term test data. These capabilities of the new power law creep equation are demonstrated using the tensile strength and creep test data measured for both pipe and tube grades of the creep-resistant steel 9Cr-1.8W-0.5Mo-V-Nb-B (P92 and T92).

  19. Value of Superficial Cultures for Prediction of Catheter-Related Bloodstream Infection in Long-Term Catheters: a Prospective Study

    PubMed Central

    Martín-Rabadán, P.; Echenagusia, A.; Camúñez, F.; Rodríguez-Rosales, G.; Simó, G.; Echenagusia, M.; Bouza, E.

    2013-01-01

    Cultures taken from the skin and from the hubs of short-term central venous catheters can help us to predict catheter-related bloodstream infections (C-RBSIs). The value of these cultures for such predictions has not been assessed in long-term catheters. Our objective was to assess the value of superficial cultures for the prediction of C-RBSI among patients with long-term catheters. Over a 2-year period, we prospectively obtained cultures from the skin overlying reservoir ports (group A) and from the skin insertion site and hubs of all tunneled catheters (group B). This routine was performed by vascular and interventional radiologists immediately before catheter removal (irrespective of the reason for withdrawal). Swabs were processed semiquantitatively. Catheter tips from both groups were cultured using Maki's semiquantitative technique and sonication. We also performed cultures of the reservoir ports at different sites. C-RBSI was defined as the isolation of the same species of microorganism(s) both in the colonized catheter and in at least 1 peripheral blood culture. We included 372 catheters (group A, 223; group B, 149) during the study period. The catheter colonization rate was 23.4% (87/372), and 28 patients had C-RBSI. Validity index values for the capacity of surface cultures to predict C-RBSI in groups A and B were, respectively, as follows: sensitivity, 23.5% and 45.5%; specificity, 59.7% and 63.0%; positive predictive value, 4.6% and 8.9%; and negative predictive value, 90.4% and 93.5%. Superficial cultures of patients with long-term catheters could help us to rule out the catheter as the portal of entry of bloodstream infections. Superficial cultures (from skin and hubs) proved to be a useful conservative diagnostic tool for ruling out C-RBSI among patients with long-term tunneled catheters and totally implantable venous access ports. PMID:23850957

  20. Long-Term Evolution of Email Networks: Statistical Regularities, Predictability and Stability of Social Behaviors.

    PubMed

    Godoy-Lorite, Antonia; Guimerà, Roger; Sales-Pardo, Marta

    2016-01-01

    In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors on the intricate microscopic process of tie replacement, but the macroscopic long-term effects of such changes remain largely unexplored. Here we investigate whether, despite the inherent randomness at the microscopic level, there are macroscopic statistical regularities in the long-term evolution of social networks. In particular, we analyze the email network of a large organization with over 1,000 individuals throughout four consecutive years. We find that, although the evolution of individual ties is highly unpredictable, the macro-evolution of social communication networks follows well-defined statistical patterns, characterized by exponentially decaying log-variations of the weight of social ties and of individuals' social strength. At the same time, we find that individuals have social signatures and communication strategies that are remarkably stable over the scale of several years.

  1. Long-Term Evolution of Email Networks: Statistical Regularities, Predictability and Stability of Social Behaviors

    PubMed Central

    Godoy-Lorite, Antonia; Guimerà, Roger; Sales-Pardo, Marta

    2016-01-01

    In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors on the intricate microscopic process of tie replacement, but the macroscopic long-term effects of such changes remain largely unexplored. Here we investigate whether, despite the inherent randomness at the microscopic level, there are macroscopic statistical regularities in the long-term evolution of social networks. In particular, we analyze the email network of a large organization with over 1,000 individuals throughout four consecutive years. We find that, although the evolution of individual ties is highly unpredictable, the macro-evolution of social communication networks follows well-defined statistical patterns, characterized by exponentially decaying log-variations of the weight of social ties and of individuals’ social strength. At the same time, we find that individuals have social signatures and communication strategies that are remarkably stable over the scale of several years. PMID:26735853

  2. Research on dynamic creep strain and settlement prediction under the subway vibration loading.

    PubMed

    Luo, Junhui; Miao, Linchang

    2016-01-01

    This research aims to explore the dynamic characteristics and settlement prediction of soft soil. Accordingly, the dynamic shear modulus formula considering the vibration frequency was utilized and the dynamic triaxial test conducted to verify the validity of the formula. Subsequently, the formula was applied to the dynamic creep strain function, with the factors influencing the improved dynamic creep strain curve of soft soil being analyzed. Meanwhile, the variation law of dynamic stress with sampling depth was obtained through the finite element simulation of subway foundation. Furthermore, the improved dynamic creep strain curve of soil layer was determined based on the dynamic stress. Thereafter, it could to estimate the long-term settlement under subway vibration loading by norms. The results revealed that the dynamic shear modulus formula is straightforward and practical in terms of its application to the vibration frequency. The values predicted using the improved dynamic creep strain formula closed to the experimental values, whilst the estimating settlement closed to the measured values obtained in the field test.

  3. Twenty four hour pulse pressure predicts long term recurrence in acute stroke patients

    PubMed Central

    Tsivgoulis, G; Spengos, K; Zakopoulos, N; Manios, E; Xinos, K; Vassilopoulos, D; Vemmos, K

    2005-01-01

    Objectives: The impact of different blood pressure (BP) components during the acute stage of stroke on the risk of recurrent stroke is controversial. The present study aimed to investigate by 24 hour BP monitoring a possible association between acute BP values and long term recurrence. Methods: A total of 339 consecutive patients with first ever acute stroke underwent 24 hour BP monitoring within 24 hours of ictus. Known stroke risk factors and clinical findings on admission were documented. Patients given antihypertensive medication during BP monitoring were excluded. The outcome of interest during the one year follow up was recurrent stroke. The Cox proportional hazard model was used to analyse association of casual and 24 hour BP recordings with one year recurrence after adjusting for stroke risk factors, baseline clinical characteristics, and secondary prevention therapies. Results: The cumulative one year recurrence rate was 9.2% (95% CI 5.9% to 12.3%). Multivariate Cox regression analyses revealed age, diabetes mellitus, and 24 hour pulse pressure (PP) as the only significant predictors for stroke recurrence. The relative risk for one year recurrence associated with every 10 mm Hg increase in 24 hour PP was 1.323 (95% CI 1.019 to 1.718, p = 0.036). Higher casual PP levels were significantly related to an increased risk of one year recurrence on univariate analysis, but not in the multivariate Cox regression model. Conclusions: Elevated 24 hour PP levels in patients with acute stroke are independently associated with higher risk of long term recurrence. Further research is required to investigate whether the risk of recurrent stroke can be reduced to a greater extent by decreasing the pulsatile component of BP in patients with acute stroke. PMID:16170077

  4. Exome Sequencing and Prediction of Long-Term Kidney Allograft Function

    PubMed Central

    Mesnard, Laurent; Muthukumar, Thangamani; Burbach, Maren; Li, Carol; Shang, Huimin; Dadhania, Darshana; Lee, John R.; Xiang, Jenny; Suberbielle, Caroline; Carmagnat, Maryvonnick; Ouali, Nacera; Rondeau, Eric; Abecassis, Michael M.; Suthanthiran, Manikkam

    2016-01-01

    Current strategies to improve graft outcome following kidney transplantation consider information at the human leukocyte antigen (HLA) loci. Cell surface antigens, in addition to HLA, may serve as the stimuli as well as the targets for the anti-allograft immune response and influence long-term graft outcomes. We therefore performed exome sequencing of DNA from kidney graft recipients and their living donors and estimated all possible cell surface antigens mismatches for a given donor/recipient pair by computing the number of amino acid mismatches in trans-membrane proteins. We designated this tally as the allogenomics mismatch score (AMS). We examined the association between the AMS and post-transplant estimated glomerular filtration rate (eGFR) using mixed models, considering transplants from three independent cohorts (a total of 53 donor-recipient pairs, 106 exomes, and 239 eGFR measurements). We found that the AMS has a significant effect on eGFR (mixed model, effect size across the entire range of the score: -19.4 [-37.7, -1.1], P = 0.0042, χ2 = 8.1919, d.f. = 1) that is independent of the HLA-A, B, DR matching, donor age, and time post-transplantation. The AMS effect is consistent across the three independent cohorts studied and similar to the strong effect size of donor age. Taken together, these results show that the AMS, a novel tool to quantify amino acid mismatches in trans-membrane proteins in individual donor/recipient pair, is a strong, robust predictor of long-term graft function in kidney transplant recipients. PMID:27684477

  5. Long term solar activity and ionospheric prediction services rendered by the National Physical Laboratory, New Delhi

    NASA Technical Reports Server (NTRS)

    Reddy, B. M.; Aggarwal, S.; Lakshmi, D. R.; Shastri, S.; Mitra, A. P.

    1979-01-01

    The data base used in solar and ionospheric prediction services is described. Present prediction techniques are discussed and compared with actual observations. Future prediction techniques using computers are also discussed.

  6. Worldwide impact of aerosol’s time scale on the predicted long-term concentrating solar power potential

    PubMed Central

    Ruiz-Arias, Jose A.; Gueymard, Christian A.; Santos-Alamillos, Francisco J.; Pozo-Vázquez, David

    2016-01-01

    Concentrating solar technologies, which are fuelled by the direct normal component of solar irradiance (DNI), are among the most promising solar technologies. Currently, the state-of the-art methods for DNI evaluation use datasets of aerosol optical depth (AOD) with only coarse (typically monthly) temporal resolution. Using daily AOD data from both site-specific observations at ground stations as well as gridded model estimates, a methodology is developed to evaluate how the calculated long-term DNI resource is affected by using AOD data averaged over periods from 1 to 30 days. It is demonstrated here that the use of monthly representations of AOD leads to systematic underestimations of the predicted long-term DNI up to 10% in some areas with high solar resource, which may result in detrimental consequences for the bankability of concentrating solar power projects. Recommendations for the use of either daily or monthly AOD data are provided on a geographical basis. PMID:27507711

  7. NASALIFE - Component Fatigue and Creep Life Prediction Program

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Murthy, Pappu L. N.; Mital, Subodh K.

    2014-01-01

    NASALIFE is a life prediction program for propulsion system components made of ceramic matrix composites (CMC) under cyclic thermo-mechanical loading and creep rupture conditions. Although the primary focus was for CMC components, the underlying methodologies are equally applicable to other material systems as well. The program references empirical data for low cycle fatigue (LCF), creep rupture, and static material properties as part of the life prediction process. Multiaxial stresses are accommodated by Von Mises based methods and a Walker model is used to address mean stress effects. Varying loads are reduced by the Rainflow counting method or a peak counting type method. Lastly, damage due to cyclic loading and creep is combined with Minor's Rule to determine damage due to cyclic loading, damage due to creep, and the total damage per mission and the number of potential missions the component can provide before failure.

  8. Phenomenological approach to precise creep life prediction by means of quantitative evaluation of strain rate acceleration in secondary creep

    NASA Astrophysics Data System (ADS)

    Sato, Hiroyuki; Miyano, Takaya

    2010-07-01

    A method of creep life prediction by means of Strain-Acceleration-Parameter (SAP), α, is presented. The authors show that the shape of creep curve can be characterized by SAP that reflects magnitude of strain-rate change in secondary creep. The SAP-values, α are evaluated on magnesium-aluminium solution hardened alloys. Reconstruction of creep curves by combinations of SAP and minimum-creep rates are successfully performed, and the curves reasonably agree with experiments. The advantage of the proposed method is that the required parameters evaluated from individual creep curves are directly connected with the minimum creep rate. The predicted times-to-failure agree well with that obtained by experiments, and possibility of precise life time prediction by SAP is pronounced.

  9. Verification of geomechanical integrity and prediction of long-term mineral trapping for the Ketzin CO2 storage pilot site

    NASA Astrophysics Data System (ADS)

    Kempka, Thomas; De Lucia, Marco; Kühn, Michael

    2014-05-01

    Static and dynamic numerical modelling generally accompany the entire CO2 storage site life cycle. Thereto, it is required to match the employed models with field observations on a regular basis in order to predict future site behaviour. We investigated the coupled processes at the Ketzin CO2 storage pilot site [1] using a model coupling concept focusing on the temporal relevance of processes involved (hydraulic, chemical and mechanical) at given time-scales (site operation, abandonment and long-term stabilization). For that purpose, long-term dynamic multi-phase flow simulations [2], [3] established the basis for all simulations discussed in the following. Hereby, pressure changes resulting in geomechanical effects are largest during site operation, whereas geochemical reactions are governed by slow kinetics resulting in a long-term stabilization. To account for mechanical integrity, which may be mainly affected during site operation, we incorporated a regional-scale coupled hydro-mechanical model. Our simulation results show maximum ground surface displacements of about 4 mm, whereas shear and tensile failure are not observed. Consequently, the CO2 storage operation at the Ketzin pilot site does not compromise reservoir, caprock and fault integrity. Chemical processes responsible for mineral trapping are expected to mainly occur during long-term stabilization at the Ketzin pilot site [4]. Hence, our previous assessment [3] was extended by integrating two long-term mineral trapping scenarios. Thereby, mineral trapping contributes to the trapping mechanisms with 11.7 % after 16,000 years of simulation in our conservative and with 30.9 % in our maximum reactivity scenarios. Dynamic flow simulations indicate that only 0.2 % of the CO2 injected (about 67,270 t CO2 in total) is in gaseous state, but structurally trapped after 16,000 years. Depending on the studied long-term scenario, CO2 dissolution is the dominating trapping mechanism with 68.9 % and 88

  10. Predicting long-term outcomes for children affected by HIV and AIDS: perspectives from the scientific study of children's development.

    PubMed

    Stein, Alan; Desmond, Christopher; Garbarino, James; Van IJzendoorn, Marinus H; Barbarin, Oscar; Black, Maureen M; Stein, Aryeh D; Hillis, Susan D; Kalichman, Seth C; Mercy, James A; Bakermans-Kranenburg, Marian J; Rapa, Elizabeth; Saul, Janet R; Dobrova-Krol, Natasha A; Richter, Linda M

    2014-07-01

    The immediate and short-term consequences of adult HIV for affected children are well documented. Little research has examined the long-term implications of childhood adversity stemming from caregiver HIV infection. Through overviews provided by experts in the field, together with an iterative process of consultation and refinement, we have extracted insights from the broader field of child development of relevance to predicting the long-term consequences to children affected by HIV and AIDS. We focus on what is known about the impact of adversities similar to those experienced by HIV-affected children, and for which there is longitudinal evidence. Cautioning that findings are not directly transferable across children or contexts, we examine findings from the study of parental death, divorce, poor parental mental health, institutionalization, undernutrition, and exposure to violence. Regardless of the type of adversity, the majority of children manifest resilience and do not experience any long-term negative consequences. However, a significant minority do and these children experience not one, but multiple problems, which frequently endure over time in the absence of support and opportunities for recovery. As a result, they are highly likely to suffer numerous and enduring impacts. These insights suggest a new strategic approach to interventions for children affected by HIV and AIDS, one that effectively combines a universal lattice of protection with intensive intervention targeted to selected children and families.

  11. Potential Role of Plasma Myeloperoxidase Level in Predicting Long-Term Outcome of Acute Myocardial Infarction

    PubMed Central

    Kaya, Mehmet Gungor; Yalcin, Ridvan; Okyay, Kaan; Poyraz, Fatih; Bayraktar, Nilufer; Pasaoglu, Hatice; Boyaci, Bulent; Cengel, Atiye

    2012-01-01

    We investigated the prognostic importance of plasma myeloperoxidase levels in patients with ST-elevation myocardial infarction (STEMI) at long-term follow-up, and we analyzed the correlations between plasma myeloperoxidase levels and other biochemical values. We evaluated 73 consecutive patients (56 men; mean age, 56 ±11 yr) diagnosed with acute STEMI and 46 age- and sex-matched healthy control participants. Patients were divided into 2 groups according to the median myeloperoxidase level (Group 1: plasma myeloperoxidase ≤68 ng/mL; and Group 2: plasma myeloperoxidase >68 ng/mL). Patients were monitored for the occurrence of major adverse cardiovascular events (MACE), which were defined as cardiac death; reinfarction; new hospital admission for angina; heart failure; and revascularization procedures. The mean follow-up period was 25 ± 16 months. Plasma myeloperoxidase levels were higher in STEMI patients than in control participants (82 ± 34 vs 20 ±12 ng/mL; P=0.001). Composite MACE occurred in 12 patients with high myeloperoxidase levels (33%) and in 4 patients with low myeloperoxidase levels (11%) (P=0.02). The incidences of nonfatal recurrent myocardial infarction and verified cardiac death were higher in the high-mye-loperoxidase group. In multivariate analysis, high plasma myeloperoxidase levels were independent predictors of MACE (odds ratio = 3.843; <95% confidence interval, 1.625–6.563; P=0.003). High plasma myeloperoxidase levels identify patients with a worse prognosis after acute STEMI at 2-year follow-up. Evaluation of plasma myeloperoxidase levels might be useful in determining patients at high risk of death and MACE who can benefit from further aggressive treatment and closer follow-up. PMID:22949765

  12. Potential role of plasma myeloperoxidase level in predicting long-term outcome of acute myocardial infarction.

    PubMed

    Kaya, Mehmet Gungor; Yalcin, Ridvan; Okyay, Kaan; Poyraz, Fatih; Bayraktar, Nilufer; Pasaoglu, Hatice; Boyaci, Bulent; Cengel, Atiye

    2012-01-01

    We investigated the prognostic importance of plasma myeloperoxidase levels in patients with ST-elevation myocardial infarction (STEMI) at long-term follow-up, and we analyzed the correlations between plasma myeloperoxidase levels and other biochemical values. We evaluated 73 consecutive patients (56 men; mean age, 56 ± 11 yr) diagnosed with acute STEMI and 46 age- and sex-matched healthy control participants. Patients were divided into 2 groups according to the median myeloperoxidase level (Group 1: plasma myeloperoxidase ≤ 68 ng/mL; and Group 2: plasma myeloperoxidase > 68 ng/mL). Patients were monitored for the occurrence of major adverse cardiovascular events (MACE), which were defined as cardiac death; reinfarction; new hospital admission for angina; heart failure; and revascularization procedures. The mean follow-up period was 25 ± 16 months. Plasma myeloperoxidase levels were higher in STEMI patients than in control participants (82 ± 34 vs 20 ± 12 ng/mL; P = 0.001). Composite MACE occurred in 12 patients with high myeloperoxidase levels (33%) and in 4 patients with low myeloperoxidase levels (11%) (P = 0.02). The incidences of nonfatal recurrent myocardial infarction and verified cardiac death were higher in the high-myeloperoxidase group. In multivariate analysis, high plasma myeloperoxidase levels were independent predictors of MACE (odds ratio = 3.843; <95% confidence interval, 1.625-6.563; P = 0.003). High plasma myeloperoxidase levels identify patients with a worse prognosis after acute STEMI at 2-year follow-up. Evaluation of plasma myeloperoxidase levels might be useful in determining patients at high risk of death and MACE who can benefit from further aggressive treatment and closer follow-up.

  13. Creep-rupture behavior of candidate Stirling engine alloys after long-term aging at 760/sup 0/C in low-pressure hydrogen

    SciTech Connect

    Titran, R.H.

    1984-05-01

    Nine candidate Stirling automotive engine alloys were aged at 760/sup 0/C for 3500 h in low pressure hydrogen or argon to determine the resulting effects on mechanical behavior. Candidate heater head tube alloys were CG-27, W545, 12RN72, INCONEL-718, and HS-188 while candidate cast cylinder-regenerator housing alloys were SA-F11, CRM-6D, XF-818, and HS-31. Aging per se is detrimental to the creep-rupture and tensile strengths of the iron-base alloys. The presence of hydrogen does not significantly contribute to strength degradation. Based on current MOD 1A Stirling engine design criteria of a 55% urban - 45% highway driving cycle; CG-27 has adequate 3500 h - 87/sup 0/C creep-rupture strength and SA-F11, CRM-6D, and XF-818 have adequate 3500 h - 775/sup 0/C creep-rupture strength.

  14. Creep-rupture behavior of candidate Stirling engine alloys after long-term aging at 760 deg C in low-pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Titran, R. H.

    1984-01-01

    Nine candidate Stirling automotive engine alloys were aged at 760 C for 3500 hr in low pressure hydrogen or argon to determine the resulting effects on mechanical behavior. Candidate heater head tube alloys were CG-27, W545, 12RN72, INCONEL-718, and HS-188 while candidate cast cylinder-regenerator housing alloys were SA-F11, CRM-6D, XF-818, and HS-31. Aging per se is detrimental to the creep rupture and tensile strengths of the iron base alloys. The presence of hydrogen does not significantly contribute to strength degradation. Based percent highway driving cycle; CG-27 has adequate 3500 hr - 870 C creep rupture strength and SA-Fll, CRM-6D, and XF-818 have adequate 3500 hr - 775 C creep rupture strength.

  15. Change in high-temperature strength properties of 12Kh1MF steel in long-term loading under creep conditions

    SciTech Connect

    Shron, R.Z.; Mints, I.I.; Shul`gina, N.G.

    1995-01-01

    Stress-rupture strength tests were made of metal steam pipe (12Kh1MF steel) in various conditions, the original, after aging under laboratory conditions (580{degrees}C, 10,000 h), and after long service. It was shown that the more the steel is hardened by heat treatment or cold plastic working in the original condition, the less it hardens in creep. It was established that softening in creep of steel with a moderate yield strength is caused primarily by aging and with a high yield strength by pore formation.

  16. Evaluation of the biotic ligand model to predict long-term toxicity of nickel to Hyalella azteca.

    PubMed

    Schroeder, J E; Borgmann, U; Dixon, D G

    2010-11-01

    Three models were developed and evaluated for their ability to predict long-term bioaccumulation of nickel (Ni) and its toxicity to Hyalella azteca using data from 28-d toxicity tests. One of the models was based on competitive action of Ni with Ca and H (the biotic ligand model; BLM), and the other two models included expressions for the potential noncompetitive action of calcium on the ligand (i.e., acclimation), in addition to, or instead of, its competitive action (not accounted for in the BLM). Each model was able to predict lethal accumulation 50 (accumulation at 50% mortality; LA50s) within a factor of 2 of the corresponding observed LA50. The mean predicted LA50 from all three models was within 13% of the observed mean LA50 of 0.90 µmol/g (dry weight). The median lethal concentrations (LC50s) predicted by the three models were similar and were within a factor of 2 of the observed LC50s for 11 of 13 tests, providing encouragement for further development of a long-term Ni BLM. The similar performance of models based on competitive or noncompetitive action may reflect limitations in the data set or may suggest that effects of calcium on the ligand (L(T)) were insufficient to hamper the functionality of the competitive model or that the LA50/L(T) ratio, rather than the LA50 and L(T), is constant.

  17. Cephalometric variables predicting the long-term success or failure of combined rapid maxillary expansion and facial mask therapy.

    PubMed

    Baccetti, Tiziano; Franchi, Lorenzo; McNamara, James A

    2004-07-01

    The aim of this study was to select a model of cephalometric variables to predict the results of early treatment of Class III malocclusion with rapid maxillary expansion and facemask therapy followed by comprehensive treatment with fixed appliances. Lateral cephalograms of 42 patients (20 boys, 22 girls) with Class III malocclusion were analyzed at the start of treatment (mean age 8 years 6 months +/- 2 years, at stage I in cervical vertebral maturation). All patients were reevaluated after a mean period of 6 years 6 months (at stage IV or V in cervical vertebral maturation) that included active treatment plus retention. At this time, the sample was divided into 2 groups according to occlusal criteria: a successful group (30 patients) and an unsuccessful group (12 patients). Discriminant analysis was applied to select pretreatment predictive variables of long-term treatment outcome. Stepwise variable selection of the cephalometric measurements at the first observation identified 3 predictive variables. Orthopedic treatment of Class III malocclusion might be unfavorable over the long term when a patient's pretreatment cephalometric records exhibit a long mandibular ramus (ie, increased posterior facial height), an acute cranial base angle, and a steep mandibular plane angle. On the basis of the equation generated by the multivariate statistical method, the outcome of interceptive orthopedic treatment for each new patient with Class III malocclusion can be predicted with a probability error of 16.7%.

  18. Nuclear Waste Disposal and Strategies for Predicting Long-Term Performance of Material

    SciTech Connect

    Wicks, G G

    2001-03-28

    Ceramics have been an important part of the nuclear community for many years. On December 2, 1942, an historic event occurred under the West Stands of Stagg Field, at the University of Chicago. Man initiated his first self-sustaining nuclear chain reaction and controlled it. The impact of this event on civilization is considered by many as monumental and compared by some to other significant events in history, such as the invention of the steam engine and the manufacturing of the first automobile. Making this event possible and the successful operation of this first man-made nuclear reactor, was the use of forty tons of UO2. The use of natural or enriched UO2 is still used today as a nuclear fuel in many nuclear power plants operating world-wide. Other ceramic materials, such as 238Pu, are used for other important purposes, such as ceramic fuels for space exploration to provide electrical power to operate instruments on board spacecrafts. Radioisotopic Thermoelectric Generators (RTGs) are used to supply electrical power and consist of a nuclear heat source and converter to transform heat energy from radioactive decay into electrical power, thus providing reliable and relatively uniform power over the very long lifetime of a mission. These sources have been used in the Galileo spacecraft orbiting Jupiter and for scientific investigations of Saturn with the Cassini spacecraft. Still another very important series of applications using the unique properties of ceramics in the nuclear field, are as immobilization matrices for management of some of the most hazardous wastes known to man. For example, in long-term management of radioactive and hazardous wastes, glass matrices are currently in production immobilizing high-level radioactive materials, and cementious forms have also been produced to incorporate low level wastes. Also, as part of nuclear disarmament activities, assemblages of crystalline phases are being developed for immobilizing weapons grade plutonium, to

  19. Excess Body Mass Index Loss at 3 Months: A Predictive Factor of Long-Term Result after Sleeve Gastrectomy

    PubMed Central

    Philouze, Guillaume; Voitellier, Eglantine; Lacaze, Laurence; Huet, Emmanuel; Gancel, Antoine; Prévost, Gaëtan

    2017-01-01

    Introduction. Laparoscopic Sleeve Gastrectomy (SG) is considered as successful if the percentage of Excess Body Mass Index Loss (% EBMIL) remains constant over 50% with long-term follow-up. The aim of this study was to evaluate whether early % EBMIL was predictive of success after SG. Methods. This retrospective study included patients who had SG with two years of follow-up. Patients had follow-up appointments at 3 (M3), 6, 12, and 24 months (M24). Data as weight and Body Mass Index (BMI) were collected systematically. We estimated the % EBMIL necessary to establish a correlation between M3 and M24 compared to % EBMIL speeds and calculated a limit value of % EBMIL predictive of success. Results. Data at operative time, M3, and M24 were available for 128 patients. Pearson test showed a correlation between % EBMIL at M3 and that at M24 (r = 0.74; p < 0.0001). % EBMIL speed between surgery and M3 (p = 0.0011) was significant but not between M3 and M24. A linear regression analysis proved that % EBMIL over 20.1% at M3 (p < 0.0001) predicted a final % EBMIL over 50%. Conclusions. % EBMIL at M3 after SG is correlated with % EBMIL in the long term. % EBMIL speed was significant in the first 3 months. % EBMIL over 20.1% at M3 leads to the success of SG. PMID:28250984

  20. Long-term prediction of fish growth under varying ambient temperature using a multiscale dynamic model

    PubMed Central

    2009-01-01

    Background Feed composition has a large impact on the growth of animals, particularly marine fish. We have developed a quantitative dynamic model that can predict the growth and body composition of marine fish for a given feed composition over a timespan of several months. The model takes into consideration the effects of environmental factors, particularly temperature, on growth, and it incorporates detailed kinetics describing the main metabolic processes (protein, lipid, and central metabolism) known to play major roles in growth and body composition. Results For validation, we compared our model's predictions with the results of several experimental studies. We showed that the model gives reliable predictions of growth, nutrient utilization (including amino acid retention), and body composition over a timespan of several months, longer than most of the previously developed predictive models. Conclusion We demonstrate that, despite the difficulties involved, multiscale models in biology can yield reasonable and useful results. The model predictions are reliable over several timescales and in the presence of strong temperature fluctuations, which are crucial factors for modeling marine organism growth. The model provides important improvements over existing models. PMID:19903354

  1. The effects of demography and long-term selection on the accuracy of genomic prediction with sequence data.

    PubMed

    MacLeod, Iona M; Hayes, Ben J; Goddard, Michael E

    2014-12-01

    The use of dense SNPs to predict the genetic value of an individual for a complex trait is often referred to as "genomic selection" in livestock and crops, but is also relevant to human genetics to predict, for example, complex genetic disease risk. The accuracy of prediction depends on the strength of linkage disequilibrium (LD) between SNPs and causal mutations. If sequence data were used instead of dense SNPs, accuracy should increase because causal mutations are present, but demographic history and long-term negative selection also influence accuracy. We therefore evaluated genomic prediction, using simulated sequence in two contrasting populations: one reducing from an ancestrally large effective population size (Ne) to a small one, with high LD common in domestic livestock, while the second had a large constant-sized Ne with low LD similar to that in some human or outbred plant populations. There were two scenarios in each population; causal variants were either neutral or under long-term negative selection. For large Ne, sequence data led to a 22% increase in accuracy relative to ∼600K SNP chip data with a Bayesian analysis and a more modest advantage with a BLUP analysis. This advantage increased when causal variants were influenced by negative selection, and accuracy persisted when 10 generations separated reference and validation populations. However, in the reducing Ne population, there was little advantage for sequence even with negative selection. This study demonstrates the joint influence of demography and selection on accuracy of prediction and improves our understanding of how best to exploit sequence for genomic prediction.

  2. Using Forecasting to Predict Long-Term Resource Utilization for Web Services

    ERIC Educational Resources Information Center

    Yoas, Daniel W.

    2013-01-01

    Researchers have spent years understanding resource utilization to improve scheduling, load balancing, and system management through short-term prediction of resource utilization. Early research focused primarily on single operating systems; later, interest shifted to distributed systems and, finally, into web services. In each case researchers…

  3. Prediction of Long-Term Alcohol Use, Drug Use, and Criminality among Inhalant Users.

    ERIC Educational Resources Information Center

    McBride, Anthony A.; And Others

    1991-01-01

    At 4-year followup on 110 Mexican-American adolescents in a drug abuse prevention program, association with deviant peers was strongly predictive of alcohol and drug use and criminality, whereas parental influences were minor predictors. Low school satisfaction was related to greater drug use, particularly for females. (Author/SV)

  4. Evaluation and prediction of long-term environmental effects of nonmetallic materials, second phase

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Changes in the functional properties of a number of nonmetallic materials were evaluated experimentally as a function of simulated space environments and to use such data to develop models for accelerated test methods useful for predicting such behavioral changes. The effects of changed particle irradiations on candidate space materials are evaluated.

  5. Geochemical modelling for predicting the long-term performance of zeolite-PRB to treat lead contaminated groundwater

    NASA Astrophysics Data System (ADS)

    Obiri-Nyarko, Franklin; Kwiatkowska-Malina, Jolanta; Malina, Grzegorz; Kasela, Tomasz

    2015-06-01

    The feasibility of using geochemical modelling to predict the performance of a zeolite-permeable reactive barrier (PRB) for treating lead (Pb2 +) contaminated water was investigated in this study. A short-term laboratory column experiment was first performed with the zeolite (clinoptilolite) until the elution of 50 PV (1 PV = ca. 283 mL). Geochemical simulations of the one-dimensional transport of the Pb2+, considering removal processes including: ion-exchange, adsorption and complexation; the concomitant release of exchangeable cations (Ca2 +, Mg2 +, Na+, and K+) and the changes in pH were subsequently performed using the geochemical model PHREEQC. The results showed a reasonable agreement between the experimental results and the numerical simulations, with the exception of Ca2 + for which a great discrepancy was observed. The model also indicated the formation of secondary mineral precipitates such as goethite and hematite throughout the experiment, of which the effect on the hydraulic conductivity was found to be negligible. The results were further used to extrapolate the long-term performance of the zeolite. We found the capacity would be completely exhausted at PV = 250 (ca. 3 days). The study, thus, generally demonstrates the applicability of PHREEQC to predict the short and long-term performance of zeolite-PRBs. Therefore, it can be used to assist in the design and for management purposes of such barriers.

  6. Severity of Acute Respiratory Distress Syndrome in haematology patients: long-term impact and early predictive factors.

    PubMed

    Lagier, D; Platon, L; Chow-Chine, L; Sannini, A; Bisbal, M; Brun, J-P; Blache, J-L; Faucher, M; Mokart, D

    2016-09-01

    Severe forms of acute respiratory distress syndrome in patients with haematological diseases expose clinicians to specific medical and ethical considerations. We prospectively followed 143 patients with haematological malignancies, and whose lungs were mechanically ventilated for more than 24 h, over a 5-y period. We sought to identify prognostic factors of long-term outcome, and in particular to evaluate the impact of the severity of acute respiratory distress syndrome in these patients. A secondary objective was to identify the early (first 48 h from ICU admission) predictive factors for acute respiratory distress syndrome severity. An evolutive haematological disease (HR 1.71; 95% CI 1.13-2.58), moderate to severe acute respiratory distress syndrome (HR 1.81; 95% CI 1.13-2.69) and need for renal replacement therapy (HR 2.24; 95% CI 1.52-3.31) were associated with long-term mortality. Resolution of neutropaenia during ICU stay (HR 0.63; 95% CI 0.42-0.94) and early microbiological documentation (HR 0.62; 95% CI 0.42-0.91) were associated with survival. The extent of pulmonary infiltration observed on the first chest X-ray and the diagnosis of invasive fungal infection were the most relevant early predictive factors of the severity of acute respiratory distress syndrome.

  7. Geochemical modelling for predicting the long-term performance of zeolite-PRB to treat lead contaminated groundwater.

    PubMed

    Obiri-Nyarko, Franklin; Kwiatkowska-Malina, Jolanta; Malina, Grzegorz; Kasela, Tomasz

    2015-01-01

    The feasibility of using geochemical modelling to predict the performance of a zeolite-permeable reactive barrier (PRB) for treating lead (Pb(2+)) contaminated water was investigated in this study. A short-term laboratory column experiment was first performed with the zeolite (clinoptilolite) until the elution of 50 PV (1 PV=ca. 283 mL). Geochemical simulations of the one-dimensional transport of the Pb(2+), considering removal processes including: ion-exchange, adsorption and complexation; the concomitant release of exchangeable cations (Ca(2+), Mg(2+), Na(+), and K(+)) and the changes in pH were subsequently performed using the geochemical model PHREEQC. The results showed a reasonable agreement between the experimental results and the numerical simulations, with the exception of Ca(2+) for which a great discrepancy was observed. The model also indicated the formation of secondary mineral precipitates such as goethite and hematite throughout the experiment, of which the effect on the hydraulic conductivity was found to be negligible. The results were further used to extrapolate the long-term performance of the zeolite. We found the capacity would be completely exhausted at PV=250 (ca. 3 days). The study, thus, generally demonstrates the applicability of PHREEQC to predict the short and long-term performance of zeolite-PRBs. Therefore, it can be used to assist in the design and for management purposes of such barriers.

  8. Future climate change is predicted to shift long-term persistence zones in the cold-temperate kelp Laminaria hyperborea.

    PubMed

    Assis, Jorge; Lucas, Ana Vaz; Bárbara, Ignacio; Serrão, Ester Álvares

    2016-02-01

    Global climate change is shifting species distributions worldwide. At rear edges (warmer, low latitude range margins), the consequences of small variations in environmental conditions can be magnified, producing large negative effects on species ranges. A major outcome of shifts in distributions that only recently received attention is the potential to reduce the levels of intra-specific diversity and consequently the global evolutionary and adaptive capacity of species to face novel disturbances. This is particularly important for low dispersal marine species, such as kelps, that generally retain high and unique genetic diversity at rear ranges resulting from long-term persistence, while ranges shifts during climatic glacial/interglacial cycles. Using ecological niche modelling, we (1) infer the major environmental forces shaping the distribution of a cold-temperate kelp, Laminaria hyperborea (Gunnerus) Foslie, and we (2) predict the effect of past climate changes in shaping regions of long-term persistence (i.e., climatic refugia), where this species might hypothetically harbour higher genetic diversity given the absence of bottlenecks and local extinctions over the long term. We further (3) assessed the consequences of future climate for the fate of L. hyperborea using different scenarios of greenhouse gas emissions (RCP 2.6 and RCP 8.5). Results show NW Iberia, SW Ireland and W English Channel, Faroe Islands and S Iceland, as regions where L. hyperborea may have persisted during past climate extremes until present day. All predictions for the future showed expansions to northern territories coupled with the significant loss of suitable habitats at low latitude range margins, where long-term persistence was inferred (e.g., NW Iberia). This pattern was particularly evident in the most agressive scenario of climate change (RCP 8.5), likely driving major biodiversity loss, changes in ecosystem functioning and the impoverishment of the global gene pool of L

  9. Design prediction for long term stress rupture service of composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Robinson, Ernest Y.

    1992-01-01

    Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

  10. Socioeconomic position predicts long-term depression trajectory: a 13-year follow-up of the GAZEL cohort study.

    PubMed

    Melchior, M; Chastang, J-F; Head, J; Goldberg, M; Zins, M; Nabi, H; Younès, N

    2013-01-01

    Individuals with low socioeconomic position have high rates of depression; however, it is not clear whether this reflects higher incidence or longer persistence of disorder. Past research focused on high-risk samples, and risk factors of long-term depression in the population are less well known. Our aim was to test the hypothesis that socioeconomic position predicts depression trajectory over 13 years of follow-up in a community sample. We studied 12 650 individuals participating in the French GAZEL study. Depression was assessed by the Center for Epidemiological Studies-Depression scale in 1996, 1999, 2002, 2005 and 2008. These five assessments served to estimate longitudinal depression trajectories (no depression, decreasing depression, intermediate/increasing depression, persistent depression). Socioeconomic position was measured by occupational grade. Covariates included year of birth, marital status, tobacco smoking, alcohol consumption, body mass index, negative life events and preexisting psychological and non-psychological health problems. Data were analyzed using multinomial regression, separately in men and women. Overall, participants in intermediate and low occupational grades were significantly more likely than those in high grades to have an unfavorable depression trajectory and to experience persistent depression (age-adjusted ORs: respectively 1.40, 95% confidence interval (CI) 1.16-1.70 and 2.65, 95% CI 2.04-3.45 in men, 2.48, 95% CI 1.36-4.54 and 4.53, 95% CI 2.38-8.63 in women). In multivariate models, the socioeconomic gradient in long-term depression decreased by 21-59% in men and women. Long-term depression trajectories appear to follow a socioeconomic gradient; therefore, efforts aiming to reduce the burden of depression should address the needs of the whole population rather than exclusively focus on high-risk groups.

  11. Influence of long-term aging and superimposed creep stress on the microstructure of 2.25cr-1Mo steel

    NASA Astrophysics Data System (ADS)

    Gope, N.; Chatterjee, Amit; Mukherjee, T.; Sarma, D. S.

    1993-02-01

    To understand the influence of high-temperature aging and superimposed creep stress on the microstructural variations in a 2.25Cr-1Mo steel, the shoulder and gage portions of the specimens subjected to stress-rupture tests at 540 °C and 580 °C have been studied by transmission electron microscopy. In the normalized and tempered condition, the steel exhibited a tempered bainitic structure and the carbides were present as M3C globules, M2C platelets, and M23C6 rectangular parallelepipeds. Aging the steel at 540 °C for 7022 hours or 17,946 hours resulted in considerable coarsening of M2C and caused precipitation of M6C carbides. The superimposed creep stress enhanced the M2C precipitation. The ferrite matrix exhibited some recovery in the specimens exposed for 17,946 hours. While M2C platelets were observed in a few areas after 14,836 hours of aging at 580 °C, this carbide was virtually nonexistent when a stress of 78 MPa was superimposed. Amounts of M23C6 persisted throughout the tests at both 540 °C and 580 °C. The M6C carbide became more predominant after long exposure at 580 °C. The ferrite matrix recovered considerably in specimens subjected to creep stress at 580 °C for 14,836 hours.

  12. Evaluation and prediction of long-term environmental effects on non metallic materials

    NASA Technical Reports Server (NTRS)

    Papazian, H.

    1985-01-01

    Predictive modeling of environmental conditions on nonmetallic materials was studied. The in-flight data of the atomic oxygen reaction with carbon and osmium, the laboratory and in-flight data of the atomic oxygen reaction with polymeric films and the effect of electron irradiation on the rates of oxidation are discussed. No information is found that can be used to model such effects on composites. The effects of the space environment on thermal control coatings and its effect on the space station are examined.

  13. Evaluation and prediction of long term space environmental effects on non-metallic materials

    NASA Technical Reports Server (NTRS)

    Shepic, J. A.

    1980-01-01

    The effects of prolonged spacecraft materials were determined and the results compared with predicted behavior. The adhesion and dielectric properties of poly-thermaleze and therm-amid magnet wire insulation were studied. The tensile properties of Lexan, polyurethane, polyethelyne, lucite, and nylon were studied well as the flexure and tensile characteristic of Adlock 851, a phenolic laminate. The volume resistivity of Cho-seal, a conductive elastomer was also a examined. Tables show the time exposed at thermal vacuum, and the high, low, and average MPA and KSI.

  14. Age of onset of child maltreatment predicts long-term mental health outcomes.

    PubMed

    Kaplow, Julie B; Widom, Cathy Spatz

    2007-02-01

    The authors tested the hypothesis that children who are maltreated earlier in life are at greater risk for poor psychological functioning in adulthood than those maltreated later in life. Age of onset of maltreatment was assessed with 3 classifications: (a) continuous (ages 0-11 years); (b) dichotomous (early [ages 0-5 years] vs. later [ages 6-11 years]); and (c) developmental (infancy [ages 0-2 years], preschool [ages 3-5 years], early school age [ages 6-8 years], and school age [ages 9-11 years]). Individuals with documented cases of physical and sexual abuse and neglect prior to age 12 (N=496) were followed up and assessed in adulthood. Results indicated that an earlier onset of maltreatment, measured dichotomously and developmentally, predicted more symptoms of anxiety and depression in adulthood, while controlling for gender, race, current age, and other abuse reports. Later onset of maltreatment, measured continuously or developmentally, was predictive of more behavioral problems in adulthood. Implications for the assessment of maltreated children, the prevention of adult psychopathology, and the classification of age of maltreatment onset are discussed.

  15. Utility of the Revised Level of Service Inventory (LSI-R) in predicting recidivism after long-term incarceration.

    PubMed

    Manchak, Sarah M; Skeem, Jennifer Lynne; Douglas, Kevin S

    2008-12-01

    Assessing an inmate's risk for recidivism may become more challenging as the length of incarceration increases. Although the population of Long-Term Inmates (LTIs) is burgeoning, no risk assessment tools have been specifically validated for this group. Based on a sample of 1,144 inmates released in a state without parole, we examine the utility of the Level of Service Inventory-Revised (LSI-R) in assessing risk of general and violent felony recidivism for LTIs (n = 555). Results indicate that (a) the LSI-R moderately predicts general, but not necessarily violent, recidivism, and (b) this predictive utility is not moderated by LTI status, and is based in part on ostensibly dynamic risk factors. Implications for informing parole decision-making and risk management for LTIs are discussed.

  16. Approaches for predicting long-term sickness absence. Re: Schouten et al. "Screening manual and office workers for risk of long-term sickness absence: cut-off points for the Work Ability Index".

    PubMed

    van Amelsvoort, Ludovic Gpm; Jansen, Nicole W H; Kant, I Jmert

    2015-05-01

    We read with much interest the article of Schouten et al (1) on identifying workers with a high risk for future long-term sickness absence using the Work Ability Index (WAI). The ability to identify high-risk workers might facilitate targeted interventions for such workers and, consequently, can reduce sickness absence levels and improve workers' health. Earlier studies by both Tamela et al (2), Kant et al (3), and Lexis et al (4) have demonstrated that such an approach, based on the identification of high-risk workers and a subsequent intervention, can be effectively applied in practice to reduce sickness absence significantly. The reason for our letter on Schouten et al's article is twofold. First, by including workers already on sick leave in a study predicting long-term sick leave will result in an overestimation of the predictive properties of the instrument and biased predictors, especially when also the outcome of interest is included as a factor in the prediction model. Second, we object to the use of the term "screening" when subjects with the condition screened for are included in the study. Reinforced by the inclusion of sickness absence in the prediction model, including workers already on sick leave will shift the focus of the study findings towards the prediction of (re)current sickness absence and workers with a below-average return-to-work rate, rather than the identification of workers at high risk for the onset of future long-term sickness absence. The possibilities for prevention will shift from pure secondary prevention to a mix of secondary and tertiary prevention. As a consequence, the predictors of the model presented in the Schouten et al article can be used as a basis for tailoring neither preventive measures nor interventions. Moreover, including the outcome (sickness absence) as a predictor in the model, especially in a mixed population including workers with and without the condition (on sick leave), will result in biased predictors and

  17. Evolution of long-term land subsidence near Mexico City: Review, field investigations, and predictive simulations

    NASA Astrophysics Data System (ADS)

    Ortiz-Zamora, Dalia; Ortega-Guerrero, Adrian

    2010-01-01

    Aquitard consolidation in the Chalco Plain is the most recent of a series of major land subsidence problems near Mexico City caused by leaky-aquifer pumping and involving a complex distribution of basalt flows within a lacustrine sequence. This study first conducted a ground magnetic survey combined with lithologic logs to map the extension of basalts. Then it assessed the evolution of ground surface elevations and updated hydraulic heads in the aquifer and aquitard in order to verify the accuracy of previous simulations and develop new predictions on land subsidence employing a one-dimensional, nonlinear, groundwater flow-consolidation model. Results show the presence of shallow basalts that extend from Sierra Santa Catarina into the Chalco Plain, causing a differential consolidation that controls both the distribution of large-scale fractures in the aquitard and the shape of a new lake. Cumulative land subsidence in the center of the Chalco Plain reached 13 m in 2006, thus closely matching previous numerical estimations. Since 1985, the ground surface decline has continued at a rate of ˜0.40 m/yr, while the potentiometric surface decline in the aquifer proceeds at an average rate of ˜1.5 m/yr, indicating that the flow system has not yet reached steady-state conditions. Numerical predictions show that under current pumping rates, where the aquitard is 300 m, total land subsidence will reach ˜19 m by the year 2020; while where the aquitard is 140 m thick, total land subsidence will reach ˜12 m, and increase the risk of flooding and aquitard fracturing for nearby urban centers.

  18. A model integrating longshore and cross-shore processes for predicting long-term shoreline response to climate change

    USGS Publications Warehouse

    Vitousek, Sean; Barnard, Patrick; Limber, Patrick W; Erikson, Li; Cole, Blake

    2017-01-01

    We present a shoreline change model for coastal hazard assessment and management planning. The model, CoSMoS-COAST (Coastal One-line Assimilated Simulation Tool), is a transect-based, one-line model that predicts short-term and long-term shoreline response to climate change in the 21st century. The proposed model represents a novel, modular synthesis of process-based models of coastline evolution due to longshore and cross-shore transport by waves and sea-level rise. Additionally, the model uses an extended Kalman filter for data assimilation of historical shoreline positions to improve estimates of model parameters and thereby improve confidence in long-term predictions. We apply CoSMoS-COAST to simulate sandy shoreline evolution along 500 km of coastline in Southern California, which hosts complex mixtures of beach settings variably backed by dunes, bluffs, cliffs, estuaries, river mouths, and urban infrastructure, providing applicability of the model to virtually any coastal setting. Aided by data assimilation, the model is able to reproduce the observed signal of seasonal shoreline change for the hindcast period of 1995-2010, showing excellent agreement between modeled and observed beach states. The skill of the model during the hindcast period improves confidence in the model's predictive capability when applied to the forecast period (2010-2100) driven by GCM-projected wave and sea-level conditions. Predictions of shoreline change with limited human intervention indicate that 31% to 67% of Southern California beaches may become completely eroded by 2100 under sea-level rise scenarios of 0.93 to 2.0 m.

  19. Long-term potential nonlinear predictability of El Niño-La Niña events

    NASA Astrophysics Data System (ADS)

    Astudillo, H. F.; Abarca-del-Río, R.; Borotto, F. A.

    2016-08-01

    We show that the monthly recorded history (1866-2014) of the Southern Oscillation Index (SOI), a descriptor of the El Niño Southern Oscillation (ENSO) phenomenon, can be correctly described as a dynamic system supporting a potential nonlinear predictability well beyond the spring barrier. Long-term predictability is strongly connected to a detailed knowledge about the topology of the attractor obtained by embedding the SOI index in a wavelet base state space. By utilizing the state orbits on the attractor, we show that the information contained in the SOI is sufficient to provide nonlinear attractor information, allowing the detection of predictability for longer than a year: 2, 3, and 4 years in advance throughout the record with an acceptable error. This is possible due to the fact that the lower-frequency variability of the SOI presents long-term positive autocorrelation. Thus, by using complementary methods, we confirm that the reconstructed attractor of the low-frequency part (lower than 1/year) of SOI time series cannot be attributed to stochastic influences. Furthermore, we establish its multifractality. As an example of the capabilities of the methodology, we investigate a few specific El Niño (1972-1973, 1982-1983, 1997-1998) and La Niña (1973-1973, 1988-1989 and 2010-2011) events. Our results indicate that each of these present several equivalent temporal structures over other eras of these 149 years (1866-2014). Accordingly, none of these cases, including extreme events, presents temporal singularity. We conclude that the methodology's simplicity of implementation and ease of use makes it suitable for studying nonlinear predictability in any area where observations are similar to those describing the ENSO phenomenon.

  20. Long-term outcome and prediction models of activities of daily living in Alzheimer disease with cholinesterase inhibitor treatment.

    PubMed

    Wattmo, Carina; Wallin, Åsa K; Londos, Elisabet; Minthon, Lennart

    2011-01-01

    In untreated patients with Alzheimer disease (AD) the functional ability is gradually lost. What happens to the patients after continuous long-term cholinesterase inhibitor (ChEI) treatment is less investigated. The objective of this study was to describe the longitudinal functional outcome and analyze factors affecting the outcome in ChEI-treated patients. In an open, 3-year, nonrandomized, prospective, multicenter study in a routine clinical setting, 790 patients were treated with either donepezil, rivastigmine, or galantamine. At baseline and every 6 months, they were assessed with several rating scales including Instrumental Activities of Daily Living (IADL), Physical Self-Maintenance Scale (PSMS), and Mini-Mental State Examination (MMSE). A faster functional decline was associated with lower cognitive ability at baseline, older age, and the interaction of higher education and longer time in the study. The patients residing with a spouse or relative showed slower deterioration in IADL score. A higher mean dose of ChEI, regardless of drug agent, was also related to slower instrumental ADL decline. Prediction models for longitudinal functional outcome were provided. AD severity at baseline is a key factor in obtaining reliable clinical prognoses of the long-term ADL ability. The dosage of ChEI treatment could possibly lead to a different functional outcome.

  1. From Gaged to Ungaged- Predicting Long-term Environmental Flows, and Ecosystems Responses.

    NASA Astrophysics Data System (ADS)

    Sengupta, A.; Adams, S. K.; Stein, E. D.; Mazor, R.; Bledsoe, B. P.

    2015-12-01

    Modern management needs, such as water supply, quality, and ecosystem protection place numerous demands on instream flows. Many regions are interested in developing numeric flow criteria as a way of ensuring maintenance of flow patterns that protect biological resources while meeting other demands. Developing flow criteria requires the capacity to generate reliable time series of the daily flow at any stream reach of interest and to relate flow patterns to biological indicators of stream health. Most stream reaches are not gaged, and it is impractical to develop detailed models for all reaches where flow alteration needs to be evaluated. We present a novel mechanistic approach to efficiently predict flows and flow alteration at all ungaged stream locations within a region of interest. We used an "ensemble approach" whereby a series of regionally representative models were developed and calibrated. New sites of interest are assigned to one of the ensemble models based on similarity of catchment properties. For southern California, we selected 43 gaged sites representing the range of geomorphology, and watershed characteristics of streams in the region. For each gaged site, we developed a hydrologic model (HEC-HMS) to predict daily flows for a period representing dry, wet and normal precipitation. The final goal is to relate flow alterations to ecological responses, the models were calibrated to three separate performance metrics that reflect conditions important for instream biological communities- proportion of low flow days, flashiness and Nash Sutcliffe efficiency for overall model performance. We cross-validated the models using a "jack-knife" approach. Models were assigned to novel 840 bioassessment sites based on the results of a Random Forest model that identified catchment properties that most affected the runoff patterns. Daily flow data for existing and "reference conditions" was simulated for a 23-year period for current and reference (undeveloped

  2. Long-Term Durability of a Matrix for High-Temperature Composites Predicted

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    2001-01-01

    Polymer matrix composites (PMC's) are being increasingly used in applications where they are exposed for long durations to harsh environments such as elevated temperatures, moisture, oils and solvents, and thermal cycling. The exposure to these environments leads to the degradation of structures made from these materials. This also affects the useful lifetimes of these structures. Some of the more prominent aerospace applications of polymer matrix composites include engine supports and cowlings, reusable launch vehicle parts, radomes, thrust-vectoring flaps, and the thermal insulation of rocket motors. This demand has led to efforts to develop lightweight, high-strength, high-modulus materials that have upper-use temperatures over 316 C. A cooperative program involving two grants to the Massachusetts Institute of Technology and in-house work at the NASA Glenn Research Center was conducted to identify the mechanisms and the measurement of mechanical and physical properties that are necessary to formulate a mechanism-based model for predicting the lifetime of high-temperature polymer matrix composites. The polymer that was studied was PMR-15 polyimide, a leading matrix resin for use in high-temperature-resistant aerospace composite structures such as propulsion systems. The temperature range that was studied was from 125 to 316 C. The diffusion behavior of PMR-15 neat resin was characterized and modeled. Thermogravimetric analysis (TGA) was also conducted in nitrogen, oxygen, and air to provide quantitative information on thermal and oxidative degradation reactions. A new low-cost technique was developed to collect chemical degradation data for isothermal tests lasting up to 4000 hr in duration. In the temperature range studied, results indicate complex behavior that was not observed by previous TGA tests, including the presence of weight-gain reactions. These were found to be significant in the initial periods of aging from 125 to 225 C. Two types of weight loss

  3. Thermomechanical fatigue, oxidation, and Creep: Part II. Life prediction

    NASA Astrophysics Data System (ADS)

    Neu, R. W.; Sehitoglu, Huseyin

    1989-09-01

    A life prediction model is developed for crack nucleation and early crack growth based on fatigue, environment (oxidation), and creep damage. The model handles different strain-temperature phasings (i.e., in-phase and out-of-phase thermomechanical fatigue, isothermal fatigue, and others, including nonproportional phasings). Fatigue life predictions compare favorably with experiments in 1070 steel for a wide range of test conditions and strain-temperature phasings. An oxide growth (oxide damage) model is based on the repeated microrupture process of oxide observed from microscopic measurements. A creep damage expression, which is stress-based, is coupled with a unified constitutive equation. A set of interrupted tests was performed to provide valuable damage progression information. Tests were performed in air and in helium atmospheres to isolate creep damage from oxidation damage.

  4. Microstructure, microchemistry, and prediction of long-term diffusion behavior of chloride in concrete

    NASA Astrophysics Data System (ADS)

    Karthikeyan, T.; Dasgupta, Arup; Magudapathy, P.; Saroja, S.; Vijayalakshmi, M.; Nair, K. G. M.; Murthy, K. P. N.; Raj, Baldev

    2006-10-01

    Microstructural and microchemical features of two types of concrete are investigated employing electron and ion optical techniques. The first type is the concrete cured in seawater or normal water. The second type is concrete cured in normal water and exposed subsequently to seawater. Major constituent phases of concrete and differences in their distribution due to different curing media are identified. Chloride profiles in different concretes are evaluated using the proton induced x-ray emission technique. Diffusion coefficient D was calculated by modeling the diffusion process and comparing with measured profiles. D, thus estimated, is found to be ˜1.8×10-9 m2/s, which is higher than the reported values of ˜10-11 to 10-13 m2/s. The faster diffusion of chloride in seawater-cured concrete can be attributed to the availability of water medium in wet concrete, in the initial stages of the hydration of cement. The prediction of the concentration profile of chloride in a layer of 100 mm of 28% fly ash containing concrete over concrete exposed to seawater is carried out. For the worst scenario, analytical estimates of the concentration of chloride as a function of time at a distance of 100 mm in the fly ash containing concrete were made. The concentration profiles of chloride expected after 40 years in the fly ash-containing concrete were also estimated using diffusion coefficient values available in the literature.

  5. Functional traits predict relationship between plant abundance dynamic and long-term climate warming

    PubMed Central

    Soudzilovskaia, Nadejda A.; Elumeeva, Tatiana G.; Onipchenko, Vladimir G.; Shidakov, Islam I.; Salpagarova, Fatima S.; Khubiev, Anzor B.; Tekeev, Dzhamal K.; Cornelissen, Johannes H. C.

    2013-01-01

    Predicting climate change impact on ecosystem structure and services is one of the most important challenges in ecology. Until now, plant species response to climate change has been described at the level of fixed plant functional types, an approach limited by its inflexibility as there is much interspecific functional variation within plant functional types. Considering a plant species as a set of functional traits greatly increases our possibilities for analysis of ecosystem functioning and carbon and nutrient fluxes associated therewith. Moreover, recently assembled large-scale databases hold comprehensive per-species data on plant functional traits, allowing a detailed functional description of many plant communities on Earth. Here, we show that plant functional traits can be used as predictors of vegetation response to climate warming, accounting in our test ecosystem (the species-rich alpine belt of Caucasus mountains, Russia) for 59% of variability in the per-species abundance relation to temperature. In this mountain belt, traits that promote conservative leaf water economy (higher leaf mass per area, thicker leaves) and large investments in belowground reserves to support next year’s shoot buds (root carbon content) were the best predictors of the species increase in abundance along with temperature increase. This finding demonstrates that plant functional traits constitute a highly useful concept for forecasting changes in plant communities, and their associated ecosystem services, in response to climate change. PMID:24145400

  6. Survival Outcomes and Predictive Factors for Female Urethral Cancer: Long-term Experience with Korean Patients.

    PubMed

    Kang, Minyong; Jeong, Chang Wook; Kwak, Cheol; Kim, Hyeon Hoe; Ku, Ja Hyeon

    2015-08-01

    The aim of this study was to evaluate female urethral cancer (UCa) patients treated and followed-up during a time period spanning more than 20 yr at single institution in Korea. We reviewed medical records of 21 consecutive patients diagnosed with female UCa at our institution between 1991 and 2012. After exclusion of two patients due to undefined histology, we examined clinicopathological variables, as well as survival outcomes of 19 patients with female UCa. A Cox proportional hazards ratio model was used to identify significant predictors of prognosis according to variables. The median age at diagnosis was 59 yr, and the median follow-up duration was 87.0 months. The most common initial symptoms were voiding symptoms and blood spotting. The median tumor size was 3.4 cm, and 55% of patients had lesions involving the entire urethra. The most common histologic type was adenocarcinoma, and the second most common type was urothelial carcinoma. Fourteen patients underwent surgery, and 7 of these patients received adjuvant radiation or systemic chemotherapy. Eleven patients experienced tumor recurrence after primary therapy. Patients with high stage disease, advanced T stage (≥T3), and positive lymph nodes had worse survival outcomes compared to their counterparts. Particularly, lymph node positivity and advanced T stage were significant predictive factors for all survival outcomes. Tumor location was the only significant predictor for recurrence-free survival. Although our study included a small number of patients, it conveys valuable information about this rare female urologic malignancy in a Korean population.

  7. Serum IL-18 as biomarker in predicting long-term renal outcome among pediatric-onset systemic lupus erythematosus patients

    PubMed Central

    Wu, Chao-Yi; Yang, Huang-Yu; Yao, Tsung-Chieh; Liu, Su-Hsun; Huang, Jing-Long

    2016-01-01

    Abstract An urge of biomarker identification is needed to better monitor lupus nephritis (LN) disease activity, guide clinical treatment, and predict patient's long-term outcome. With the proinflammatory effect and its association with inflammasomes, the significance of interleukin-18 (IL-18) among pediatric-onset systemic lupus erythematous (pSLE) patient, especially, its importance in predicting long-term renal outcome was investigated. In a pSLE cohort of 96 patients with an average follow-up period of 10.39 ± 3.31 years, clinical data and laboratory workups including serum IL-18 were collected at time of disease onset and 6 months after treatment despite their initial renal status. Through Cox regression analysis, the parameters at baseline and at 6 months posttreatment were carefully analyzed. Average age of all cases was 12.74 ± 3.01 years old and 65 of them underwent renal biopsy at the time of diagnosis. Nine subjects (9.38%) progressed to end-stage renal disease (ESRD) and 2 cases (2.08%) died during follow-up. Through multivariate analysis, serum IL-18 level 6 months posttreatment was found to be the most unfavorable factor associating poor clinical outcome despite patient's initial renal status. In addition, the presentation of serum IL-18 in its correlation with SLE global disease activity as well as the presence and severity of LN were all significant (P < 0.001, P = 0.03, and P = 0.02, respectively). The histological classification of LN, however, was not associated with the level of IL-18 among the pSLE patients (P = 0.64). The role of serum IL-18 as biomarker representing global disease activity and status of renal flares among pSLE population was shown for the first time. Additionally, we have identified IL-18 at 6 months posttreatment a novel marker for long-term renal outcome prediction. PMID:27749566

  8. Clinical Significance of the Prognostic Nutritional Index for Predicting Short- and Long-Term Surgical Outcomes After Gastrectomy

    PubMed Central

    Lee, Jee Youn; Kim, Hyoung-Il; Kim, You-Na; Hong, Jung Hwa; Alshomimi, Saeed; An, Ji Yeong; Cheong, Jae-Ho; Hyung, Woo Jin; Noh, Sung Hoon; Kim, Choong-Bai

    2016-01-01

    Abstract To evaluate the predictive and prognostic significance of the prognostic nutritional index (PNI) in a large cohort of gastric cancer patients who underwent gastrectomy. Assessing a patient's immune and nutritional status, PNI has been reported as a predictive marker for surgical outcomes in various types of cancer. We retrospectively reviewed data from a prospectively maintained database of 7781 gastric cancer patients who underwent gastrectomy from January 2001 to December 2010 at a single center. From this data, we analyzed clinicopathologic characteristics, PNI, and short- and long-term surgical outcomes for each patient. We used the PNI value for the 10th percentile (46.70) of the study cohort as a cut-off for dividing patients into low and high PNI groups. Regarding short-term outcomes, multivariate analysis showed a low PNI (odds ratio [OR] = 1.505, 95% CI = 1.212–1.869, P <0.001), old age, male sex, high body mass index, medical comorbidity, total gastrectomy, and combined resection to be independent predictors of postoperative complications. Among these, only low PNI (OR = 4.279, 95% CI = 1.760–10.404, P = 0.001) and medical comorbidity were independent predictors of postoperative mortality. For long-term outcomes, low PNI was a poor prognostic factor for overall survival, but not recurrence (overall survival: hazard ratio [HR] = 1.383, 95% CI = 1.221–1.568, P < 0.001; recurrence-free survival: HR = 1.142, 95% CI = 0.985–1.325, P = 0.078). PNI can be used to predict patients at increased risk of postoperative morbidity and mortality. Although PNI was an independent prognostic factor for overall survival, the index was not associated with cancer recurrence. PMID:27149460

  9. Model-based prediction of the acute and long-term safety profile of naproxen in rats

    PubMed Central

    Sahota, Tarjinder; Sanderson, Ian; Danhof, Meindert; Della Pasqua, Oscar

    2015-01-01

    Background and Purpose Despite the increasing importance of biomarkers as predictors of drug effects, toxicology protocols continue to rely on the experimental evidence of adverse events (AEs) as a basis for establishing the link between indicators of safety and drug exposure. Furthermore, biomarkers may facilitate the translation of findings from animals to humans. Combined with a model-based approach, biomarker data have the potential to predict long-term effects arising from prolonged drug exposure. Here, we used naproxen as a paradigm to explore the feasibility of a biomarker-guided approach for the prediction of long-term AEs in humans. Experimental Approach An experimental toxicology protocol was set up for evaluating the effects of naproxen in rats, in which four active doses were tested (7.5, 15, 40 and 80 mg·kg−1). In addition to AE monitoring and histology, a few blood samples were also collected for the assessment of drug exposure, TXB2 and PGE2 levels. Non-linear mixed effects modelling was used to analyse the data and identify covariate factors on the incidence and severity of AEs. Key Results Modelling results showed that besides drug exposure, maximum PGE2 inhibition and treatment duration were also predictors of gastrointestinal ulceration. Although PGE2 levels were clearly linked to the incidence rates, it appeared that ulceration severity is better predicted by measures of drug exposure. Conclusions and Implications These results show that the use of a model-based approach provides the opportunity to integrate pharmacokinetics, pharmacodynamics and toxicity data, enabling optimization of the design, analysis and interpretation of toxicology experiments. PMID:25884765

  10. Analysis of long-term land subsidence near Mexico City: Field investigations and predictive modeling

    NASA Astrophysics Data System (ADS)

    Ortega-Guerrero, Adrian; Rudolph, David L.; Cherry, John A.

    1999-11-01

    The Mexico City region has several flat plains formed on exceptionally porous (60-90%) lacustrine deposits overlying a highly productive regional aquifer. Severe land subsidence due to consolidation of the lacustrine aquitard caused by aquifer exploitation has resulted in restrictions on pumping in the core of Mexico City. This has led to large increases in aquifer pumping in the outlying lacustrine plains where satellite communities are rapidly expanding. The Chalco Basin is one of these lacustrine areas where pumping began in the 1950s and greatly increased in the 1980s. The lacustrine sequence in the Chalco area is significantly thicker than anywhere else in the Basin of Mexico averaging 100 m and reaching a maximum thickness of 300 m. Consequently, this area is susceptible to the highest potential land subsidence effects as a result of groundwater extraction of anywhere in the basin. Land subsidence in the central part of the Chalco Basin has increased to 0.4 m/yr since 1984 and by 1991 total subsidence had reached 8 m. The rapid land subsidence in this area is causing the accumulation of meteoric waters during the rainy season resulting in extensive flooding of farmland. This study first demonstrates a methodology for combining hydraulic data from a network of monitoring wells, geotechnical data from core samples, and a compilation of historical information on land surface elevation to quantify groundwater flow and land subsidence phenomena within the rapidly subsiding Chalco Basin. Then a one-dimensional mathematical model is employed to develop predictions of future land subsidence under a range of pumping conditions. The model permits the hydraulic properties of the aquitard to vary as transient functions of hydraulic head and porosity. Simulations suggest that under current pumping rates, total land subsidence in the area of thickest lacustrine sediment will reach 15 m by the year 2010. If pumping is reduced to the extent that further decline in the

  11. Creep-rupture behavior of seven iron-base alloys after long term aging at 760 deg in low pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Witzke, W. R.; Stephens, J. R.

    1980-01-01

    Seven candidate iron-base alloys for heater tube application in the Stirling automotive engine were aged for 3500 hours at 760 C in argon and hydrogen. Aging degraded the tensile and creep-rupture properties. The presence of hydrogen during aging caused additional degradiation of the rupture strength in fine grain alloys. Based on current design criteria for the Mod 1 Stirling engine, N-155 and 19-9DL are considered the only alloys in this study with strengths adequate for heater tube service at 760 C.

  12. Cognitive-behavioral therapy for obsessive–compulsive disorder: access to treatment, prediction of long-term outcome with neuroimaging

    PubMed Central

    O’Neill, Joseph; Feusner, Jamie D

    2015-01-01

    This article reviews issues related to a major challenge to the field for obsessive–compulsive disorder (OCD): improving access to cognitive-behavioral therapy (CBT). Patient-related barriers to access include the stigma of OCD and reluctance to take on the demands of CBT. Patient-external factors include the shortage of trained CBT therapists and the high costs of CBT. The second half of the review focuses on one partial, yet plausible aid to improve access – prediction of long-term response to CBT, particularly using neuroimaging methods. Recent pilot data are presented revealing a potential for pretreatment resting-state functional magnetic resonance imaging and magnetic resonance spectroscopy of the brain to forecast OCD symptom severity up to 1 year after completing CBT. PMID:26229514

  13. Predicting long-term growth in students' mathematics achievement: the unique contributions of motivation and cognitive strategies.

    PubMed

    Murayama, Kou; Pekrun, Reinhard; Lichtenfeld, Stephanie; Vom Hofe, Rudolf

    2013-01-01

    This research examined how motivation (perceived control, intrinsic motivation, and extrinsic motivation), cognitive learning strategies (deep and surface strategies), and intelligence jointly predict long-term growth in students' mathematics achievement over 5 years. Using longitudinal data from six annual waves (Grades 5 through 10; Mage  = 11.7 years at baseline; N = 3,530), latent growth curve modeling was employed to analyze growth in achievement. Results showed that the initial level of achievement was strongly related to intelligence, with motivation and cognitive strategies explaining additional variance. In contrast, intelligence had no relation with the growth of achievement over years, whereas motivation and learning strategies were predictors of growth. These findings highlight the importance of motivation and learning strategies in facilitating adolescents' development of mathematical competencies.

  14. Cross-regional prediction of long-term trajectory of stream water DOC response to climate change

    NASA Astrophysics Data System (ADS)

    Laudon, Hjalmar; Buttle, Jim; Carey, Sean K.; McDonnell, Jeff; McGuire, Kevin; Seibert, Jan; Shanley, Jamie; Soulsby, Chris; Tetzlaff, Doerthe

    2012-09-01

    There is no scientific consensus about how dissolved organic carbon (DOC) in surface waters is regulated. Here we combine recent literature data from 49 catchments with detailed stream and catchment process information from nine well established research catchments at mid- to high latitudes to examine the question of how climate controls stream water DOC. We show for the first time that mean annual temperature (MAT) in the range from -3° to +10° C has a strong control over the regional stream water DOC concentration in catchments, with highest concentrations in areas ranging between 0° and +3° C MAT. Although relatively large deviations from this model occur for individual streams, catchment topography appears to explain much of this divergence. These findings suggest that the long-term trajectory of stream water DOC response to climate change may be more predictable than previously thought.

  15. Creep fatigue life prediction for engine hot section materials (isotropic)

    NASA Technical Reports Server (NTRS)

    Moreno, Vito; Nissley, David; Lin, Li-Sen Jim

    1985-01-01

    The first two years of a two-phase program aimed at improving the high temperature crack initiation life prediction technology for gas turbine hot section components are discussed. In Phase 1 (baseline) effort, low cycle fatigue (LCF) models, using a data base generated for a cast nickel base gas turbine hot section alloy (B1900+Hf), were evaluated for their ability to predict the crack initiation life for relevant creep-fatigue loading conditions and to define data required for determination of model constants. The variables included strain range and rate, mean strain, strain hold times and temperature. None of the models predicted all of the life trends within reasonable data requirements. A Cycle Damage Accumulation (CDA) was therefore developed which follows an exhaustion of material ductility approach. Material ductility is estimated based on observed similarities of deformation structure between fatigue, tensile and creep tests. The cycle damage function is based on total strain range, maximum stress and stress amplitude and includes both time independent and time dependent components. The CDA model accurately predicts all of the trends in creep-fatigue life with loading conditions. In addition, all of the CDA model constants are determinable from rapid cycle, fully reversed fatigue tests and monotonic tensile and/or creep data.

  16. D-dimer for prediction of long-term outcome in cryptogenic stroke patients with patent foramen ovale.

    PubMed

    Kim, Young Dae; Song, Dongbeom; Nam, Hyo Suk; Lee, Kijeong; Yoo, Joonsang; Hong, Geu-Ru; Lee, Hye Sun; Nam, Chung Mo; Heo, Ji Hoe

    2015-08-31

    Patent foramen ovale (PFO) is a potential cause of cryptogenic stroke, given the possibility of paradoxical embolism from venous to systemic circulation. D-dimer level is used to screen venous thrombosis. We investigated the risk of embolism and mortality according to the presence of PFO and D-dimer levels in cryptogenic stroke patients. A total of 570 first-ever cryptogenic stroke patients who underwent transesophageal echocardiography were included in this study. D-dimer was assessed using latex agglutination assay during admission. The association of long-term outcomes with the presence of PFO and D-dimer levels was investigated. PFO was detected in 241 patients (42.3 %). During a mean 34.0 ± 22.8 months of follow-up, all-cause death occurred in 58 (10.2 %) patients, ischaemic stroke in 33 (5.8 %), and pulmonary thromboembolism in 6 (1.1 %). Multivariate Cox regression analysis showed that a D-dimer level of > 1,000 ng/ml was an independent predictor for recurrent ischaemic stroke in patients with PFO (hazard ratio 5.341, 95 % confidence interval 1.648-17.309, p=0.005), but not in those without PFO. However, in patients without PFO, a D-dimer level of > 1,000 ng/ml was independently related with all-cause mortality. The risk of pulmonary thromboembolism tended to be high in patients with high D-dimer levels, regardless of PFO. Elevated D-dimer levels in cryptogenic stroke were predictive of the long-term outcome, which differed according to the presence of PFO. The coexistence of PFO and a high D-dimer level increased the risk of recurrent ischaemic stroke. The D-dimer test in cryptogenic stroke patients may be useful for predicting outcomes and deciding treatment strategy.

  17. Predicting long-term outcome of Internet-delivered cognitive behavior therapy for social anxiety disorder using fMRI and support vector machine learning.

    PubMed

    Månsson, K N T; Frick, A; Boraxbekk, C-J; Marquand, A F; Williams, S C R; Carlbring, P; Andersson, G; Furmark, T

    2015-03-17

    Cognitive behavior therapy (CBT) is an effective treatment for social anxiety disorder (SAD), but many patients do not respond sufficiently and a substantial proportion relapse after treatment has ended. Predicting an individual's long-term clinical response therefore remains an important challenge. This study aimed at assessing neural predictors of long-term treatment outcome in participants with SAD 1 year after completion of Internet-delivered CBT (iCBT). Twenty-six participants diagnosed with SAD underwent iCBT including attention bias modification for a total of 13 weeks. Support vector machines (SVMs), a supervised pattern recognition method allowing predictions at the individual level, were trained to separate long-term treatment responders from nonresponders based on blood oxygen level-dependent (BOLD) responses to self-referential criticism. The Clinical Global Impression-Improvement scale was the main instrument to determine treatment response at the 1-year follow-up. Results showed that the proportion of long-term responders was 52% (12/23). From multivariate BOLD responses in the dorsal anterior cingulate cortex (dACC) together with the amygdala, we were able to predict long-term response rate of iCBT with an accuracy of 92% (confidence interval 95% 73.2-97.6). This activation pattern was, however, not predictive of improvement in the continuous Liebowitz Social Anxiety Scale-Self-report version. Follow-up psychophysiological interaction analyses revealed that lower dACC-amygdala coupling was associated with better long-term treatment response. Thus, BOLD response patterns in the fear-expressing dACC-amygdala regions were highly predictive of long-term treatment outcome of iCBT, and the initial coupling between these regions differentiated long-term responders from nonresponders. The SVM-neuroimaging approach could be of particular clinical value as it allows for accurate prediction of treatment outcome at the level of the individual.

  18. SNPs in PTGS2 and LTA Predict Pain and Quality of Life in Long Term Lung Cancer Survivors

    PubMed Central

    Rausch, Sarah M.; Gonzalez, Brian D.; Clark, Matthew M.; Patten, Christi; Felten, Sara; Liu, Heshan; Li, Yafei; Sloan, Jeff; Yang, Ping

    2015-01-01

    PURPOSE Lung cancer survivors report the lowest quality of life relative to other cancer survivors. Pain is one of the most devastating, persistent, and incapacitating symptoms for lung cancer survivors. Prevalence rates vary with 80–100% of survivors experiencing cancer pain and healthcare costs are five times higher in cancer survivors with uncontrolled pain. Cancer pain often has a considerable impact on quality of life among cancer patients and cancer survivors. Therefore, early identification, and treatment is important. Although recent studies have suggested a relationship between single nucleotide polymorphisms (SNPs) in several cytokine and inflammation genes with cancer prognosis, associations with cancer pain are not clear. Therefore, the primary aim of this study was to identify SNPs related to pain in long term lung cancer survivors. PATIENTS AND METHODS Participants were enrolled in the Mayo Clinic Lung Cancer Cohort upon diagnosis of their lung cancer. 1149 Caucasian lung cancer survivors, (440 surviving < 3 years; 354 surviving 3–5 years; and 355 surviving> 5 years) completed study questionnaires and had genetic samples available. Ten SNPS from PTGS2 and LTA genes were selected based on the serum literature. Outcomes included pain, and quality of life as measured by the SF-8. RESULTS Of the 10 SNPs evaluated in LTA and PTGS2 genes, 3 were associated with pain severity (rs5277; rs1799964), social function (rs5277) and mental health (rs5275). These results suggested both specificity and consistency of these inflammatory gene SNPs in predicting pain severity in long term lung cancer survivors. CONCLUSION These results provide support for genetic predisposition to pain severity and may aid in identification of lung cancer survivors at high risk for morbidity and poor QOL. PMID:22464751

  19. Long-Term Prediction of the Demand of Colonoscopies Generated by a Population-Based Colorectal Cancer Screening Program

    PubMed Central

    Mendivil, Joan; Andreu, Montserrat; Hernández, Cristina; Castells, Xavier

    2016-01-01

    Objective To estimate the long-term need for colonoscopies after a positive fecal immunochemical test (FIT) and post-polypectomy surveillance in the context of a population-based colorectal cancer (CRC) screening program. Methods A discrete-event simulation model was built to reproduce the process of CRC screening and post-polypectomy surveillance following European guidelines in a population of 100,000 men and women aged 50–69 years over a 20-year period. Screening consisted of biennial FIT and colonoscopy in participants with positive results. The model was mainly fed using data from the first and second rounds of a Spanish program (2010–2013). Data on post-polypectomy surveillance results were obtained from the literature. A probabilistic multivariate sensitivity analysis was performed on the effect of participation, FIT positivity, and adherence to surveillance colonoscopies. The main outcome variables were the number of colonoscopies after a positive FIT, surveillance colonoscopies, and the overall number of colonoscopies. Results An average yearly number of 1,200 colonoscopies after a positive FIT were predicted per 100,000 inhabitants with a slight increase to 1,400 at the end of the 20-year period. Surveillance colonoscopies increased to an average of 1,000 per 100,000 inhabitants in the long-term, showing certain stabilization in the last years of the 20-year simulation horizon. The results were highly sensitive to FIT positivity. Conclusions Implementing a population-based CRC screening program will increase the demand for colonoscopies, which is expected to double in 20 years, mainly due to an increase in surveillance colonoscopies. PMID:27732635

  20. Predicting plant uptake and toxicity of lead (Pb) in long-term contaminated soils from derived transfer functions.

    PubMed

    Kader, Mohammed; Lamb, Dane T; Mahbub, Khandaker Rayhan; Megharaj, Mallavarapu; Naidu, Ravi

    2016-08-01

    Regulatory assessment of lead (Pb) in contaminated soils is still expressed primarily as total Pb concentrations in soil. In this study, we estimated effective concentrations (ECx) of Pb to Cucumis sativa L. (cucumber) focusing primarily on pore-water Pb data from 10 different soils after 12 weeks ageing. Phytotoxicity expressed in terms of Pb(2+) was observed to occur in the nanomolar range in neutral to alkaline soils (EC50 values 90 to 853 nM) and micromolar levels for acidic soils (EC50 values 7.35 to 9.66 μM). Internal Pb concentrations relating to toxicity (PT50) in roots and shoots also decreased with increasing pore-water pH (R (2) = 0.52 to 0.53). From a series of dose-response studies, we developed transfer functions predicting Pb uptake in C. sativa and we validated these functions with long-term Pb contaminated soils. The significant independent parameters were pore-water Pb(2+) and dissolved Pb plus dissolved organic carbon (DOC). The observed RMSE for the Pb-DOC model and Pb(2+) were 2.6 and 8.8, respectively. The Pb-DOC model tended to under-predict Pb, whilst Pb(2+) tended to over-predict accumulation despite reasonable RMSE values. Further validation is needed in soils with higher pore-water Pb solubility.

  1. Synovectomy of the elbow and radial head excision in rheumatoid arthritis. Predictive factors and long-term outcome.

    PubMed

    Gendi, N S; Axon, J M; Carr, A J; Pile, K D; Burge, P D; Mowat, A G

    1997-11-01

    We carried out a survival analysis of elbow synovectomy (ES) and excision of the radial head (RHE) performed on 171 rheumatoid elbows. The failure criteria were revision surgery (performed or desired) and/or the presence of significant or severe pain. The cumulative survival was 81% at one year which thereafter decreased by an average of 2.6% per year. The strongest predictor for success was a low preoperative range of supination-pronation when corresponding survival curves were compared. A low range of flexion-extension also predicted failure. Combining both factors gave better prediction (failure: 6.3% v 67%), but a long duration of elbow symptoms before surgery predicted failure (72%, p = 0.04). At review, there was a mean gain of 50 degrees in supination-pronation and 11 degrees in flexion-extension; both correlated with success. Failure correlated with recurrence of synovitis, elbow instability, ulnar neuropathy, poor general mobility and poor upper-limb function. The last was independently affected by the severity of RA in the ipsilateral shoulder. Our findings show that although the short-term result of ES and RHE in rheumatoid arthritis is good, the long-term outcome is poor except in a subgroup with more than 50% limitation of forearm rotation.

  2. Predictive and concurrent validity of the Braden scale in long-term care: a meta-analysis.

    PubMed

    Wilchesky, Machelle; Lungu, Ovidiu

    2015-01-01

    Pressure ulcer prevention is an important long-term care (LTC) quality indicator. While the Braden Scale is a recommended risk assessment tool, there is a paucity of information specifically pertaining to its validity within the LTC setting. We, therefore, undertook a systematic review and meta-analysis comparing Braden Scale predictive and concurrent validity within this context. We searched the Medline, EMBASE, PsychINFO and PubMed databases from 1985-2014 for studies containing the requisite information to analyze tool validity. Our initial search yielded 3,773 articles. Eleven datasets emanating from nine published studies describing 40,361 residents met all meta-analysis inclusion criteria and were analyzed using random effects models. Pooled sensitivity, specificity, positive predictive value (PPV), and negative predictive values were 86%, 38%, 28%, and 93%, respectively. Specificity was poorer in concurrent samples as compared with predictive samples (38% vs. 72%), while PPV was low in both sample types (25 and 37%). Though random effects model results showed that the Scale had good overall predictive ability [RR, 4.33; 95% CI, 3.28-5.72], none of the concurrent samples were found to have "optimal" sensitivity and specificity. In conclusion, the appropriateness of the Braden Scale in LTC is questionable given its low specificity and PPV, in particular in concurrent validity studies. Future studies should further explore the extent to which the apparent low validity of the Scale in LTC is due to the choice of cutoff point and/or preventive strategies implemented by LTC staff as a matter of course.

  3. Flexural creep behaviour of jute polypropylene composites

    NASA Astrophysics Data System (ADS)

    Chandekar, Harichandra; Chaudhari, Vikas

    2016-09-01

    Present study is about the flexural creep behaviour of jute fabric reinforced polypropylene (Jute-PP) composites. The PP sheet and alkali treated jute fabric is stacked alternately and hot pressed in compression molding machine to get Jute-PP composite laminate. The flexural creep study is carried out on dynamic mechanical analyzer. The creep behaviour of the composite is modeled using four-parameter Burgers model. Short-term accelerated creep testing is conducted which is later used to predict long term creep behaviour. The feasibility of the construction of a master curve using the time-temperature superposition (TTS) principle to predict long term creep behavior of unreinforced PP and Jute-PP composite is investigated.

  4. Development of a Generic Creep-Fatigue Life Prediction Model

    NASA Technical Reports Server (NTRS)

    Goswami, Tarun

    2002-01-01

    The objective of this research proposal is to further compile creep-fatigue data of steel alloys and superalloys used in military aircraft engines and/or rocket engines and to develop a statistical multivariate equation. The newly derived model will be a probabilistic fit to all the data compiled from various sources. Attempts will be made to procure the creep-fatigue data from NASA Glenn Research Center and other sources to further develop life prediction models for specific alloy groups. In a previous effort [1-3], a bank of creep-fatigue data has been compiled and tabulated under a range of known test parameters. These test parameters are called independent variables, namely; total strain range, strain rate, hold time, and temperature. The present research attempts to use these variables to develop a multivariate equation, which will be a probabilistic equation fitting a large database. The data predicted by the new model will be analyzed using the normal distribution fits, the closer the predicted lives are with the experimental lives (normal line 1 to 1 fit) the better the prediction. This will be evaluated in terms of a coefficient of correlation, R 2 as well. A multivariate equation developed earlier [3] has the following form, where S, R, T, and H have specific meaning discussed later.

  5. True Grit: Trait-level Perseverance and Passion for Long-term Goals Predicts Effectiveness and Retention among Novice Teachers

    PubMed Central

    Robertson-Kraft, Claire; Duckworth, Angela Lee

    2013-01-01

    Background/Context Surprisingly little progress has been made in linking teacher effectiveness and retention to factors observable at the time of hire. The rigors of teaching, particularly in low-income school districts, suggest the importance of personal qualities that have so far been difficult to measure objectively. Purpose/Objective/Research Question/Focus of Study In this study, we examine the predictive validity of personal qualities not typically collected by school districts during the hiring process. Specifically, we use a psychological framework to explore how biographical data on grit, a disposition toward perseverance and passion for long-term goals, explains variance in novice teachers’ effectiveness and retention. Research Design In two prospective, longitudinal samples of novice teachers assigned to schools in low-income districts (N = 154 and N = 307, respectively), raters blind to outcomes followed a 7-point rubric to rate grit from information on college activities and work experience extracted from teachers’ résumés. We used independent-samples t-tests and binary logistic regression models to predict teacher effectiveness and retention from these grit ratings as well as from other information (e.g., SAT scores, college GPA, interview ratings of leadership potential) available at the time of hire. Conclusions/Recommendations Grittier teachers outperformed their less gritty colleagues and were less likely to leave their classrooms mid-year. Notably, no other variables in our analysis predicted either effectiveness or retention. These findings contribute to a better understanding of what leads some novice teachers to outperform others and remain committed to the profession. In addition to informing policy decisions surrounding teacher recruitment and development, this investigation highlights the potential of a psychological framework to explain why some individuals are more successful than others in meeting the rigorous demands of teaching

  6. Masculine norms, disclosure, and childhood adversities predict long-term mental distress among men with histories of child sexual abuse.

    PubMed

    Easton, Scott D

    2014-02-01

    Child sexual abuse (CSA) can have a profound effect on the long-term mental health of boys/men. However, not all men with histories of CSA experience psychopathology. To improve prevention and intervention services, more research is needed to understand why some male survivors experience mental health problems and others do not. The purpose of this study was to examine factors related to mental distress among a large, non-clinical sample of men with histories of CSA (N=487). Using a cross-sectional design with purposive sampling from three national survivor organizations, data were collected through an anonymous Internet-based survey. Multivariate analyses found that only one of the four CSA severity variables-use of physical force by the abuser-was related to mental distress. Additional factors that were related to mental distress included the number of other childhood adversities, years until disclosure, overall response to disclosure, and conformity to masculine norms. Overall, the final model predicted 36% of the variance in the number of mental health symptoms. Mental health practitioners should include masculine norms, disclosure history, and childhood adversities in assessments and intervention planning with male survivors. To more fully explicate risk factors for psychopathology in this population, future studies with probability samples of men that focus on mediational processes and use longitudinal designs are needed.

  7. Predicting intentions for long-term anabolic-androgenic steroid use among men: a covariance structure model.

    PubMed

    Hildebrandt, Tom; Langenbucher, James; Carr, Sasha; Sanjuan, Pilar; Park, Steff

    2006-09-01

    Long-term use of anabolic-androgenic steroids (AASs) is associated with both positive and negative effects. The authors examined possible mechanisms by which these effects contribute to AAS satisfaction and predict intentions for future AAS use. Five hundred male AAS users completed an interactive Web-based instrument assessing the psychological and physical effects of AAS use. Covariance structure modeling was used to evaluate both direct and indirect effects of AAS consequences on satisfaction with AASs and intentions for future AAS use. Results suggest that gain in muscle mass and psychological benefits from AAS use uniquely contributed to both AAS satisfaction and intentions for future use. Side effects from AAS use also uniquely contributed to AAS satisfaction, but ancillary drug use was found to partially mediate this relationship, suggesting that the satisfaction of experienced AAS users is enhanced by their mastery of side effects through the use of ancillary drugs. The final model explained 29% of the variance in intentions for future AAS use. Mechanisms for sustained AAS use and implications for intervention and prevention strategies are discussed.

  8. Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds.

    PubMed

    Illán, Javier Gutiérrez; Thomas, Chris D; Jones, Julia A; Wong, Weng-Keen; Shirley, Susan M; Betts, Matthew G

    2014-11-01

    Predicting biodiversity responses to climate change remains a difficult challenge, especially in climatically complex regions where precipitation is a limiting factor. Though statistical climatic envelope models are frequently used to project future scenarios for species distributions under climate change, these models are rarely tested using empirical data. We used long-term data on bird distributions and abundance covering five states in the western US and in the Canadian province of British Columbia to test the capacity of statistical models to predict temporal changes in bird populations over a 32-year period. Using boosted regression trees, we built presence-absence and abundance models that related the presence and abundance of 132 bird species to spatial variation in climatic conditions. Presence/absence models built using 1970-1974 data forecast the distributions of the majority of species in the later time period, 1998-2002 (mean AUC = 0.79 ± 0.01). Hindcast models performed equivalently (mean AUC = 0.82 ± 0.01). Correlations between observed and predicted abundances were also statistically significant for most species (forecast mean Spearman's ρ = 0.34 ± 0.02, hindcast = 0.39 ± 0.02). The most stringent test is to test predicted changes in geographic patterns through time. Observed changes in abundance patterns were significantly positively correlated with those predicted for 59% of species (mean Spearman's ρ = 0.28 ± 0.02, across all species). Three precipitation variables (for the wettest month, breeding season, and driest month) and minimum temperature of the coldest month were the most important predictors of bird distributions and abundances in this region, and hence of abundance changes through time. Our results suggest that models describing associations between climatic variables and abundance patterns can predict changes through time for some species, and that changes in precipitation and winter temperature appear to

  9. Long-Term Care

    MedlinePlus

    ... this page please turn Javascript on. Long-Term Care What Is Long-Term Care? Long-term care involves a variety of services ... the Escape (Esc) button on your keyboard.) Most Care Provided at Home Long-term care is provided ...

  10. Daily activity level improvement with antidepressant medications predicts long-term clinical outcomes in outpatients with major depressive disorder

    PubMed Central

    Jha, Manish K; Teer, Raymond B; Minhajuddin, Abu; Greer, Tracy L; Rush, A John; Trivedi, Madhukar H

    2017-01-01

    independently predicts long-term clinical outcomes. Brief systematic assessment of activity impairment during the course of antidepressant treatment can help inform clinical decision-making. PMID:28352180

  11. Creep fatigue life prediction for engine hot section materials (isotropic)

    NASA Technical Reports Server (NTRS)

    Moreno, V.

    1983-01-01

    The activities performed during the first year of the NASA HOST Program, Creep Fatigue Life Prediction for Engine Hot Section Materials (Isotropic), being conducted by Pratt & Whitney Aircraft are summarized. The program is a 5 year, two part effort aimed at improving the high temperature crack initiation prediction technology for gas turbine hot section components. Significant results of the program produced thus far are discussed. Cast B1900 + Hf and wrought IN 718 were selected as the base and alternate materials, respectively. A single heat of B1900 + Hf was obtained and test specimens fabricated. The material was characterized with respect to grain size, gamma prime size, carbide distribution, and dislocation density. Monotonic tensile and creep testing has shown engineering properties within anticipated scatter for this material. Examination of the tensile tests has shown a transition from inhomogeneous planar slip within the grains at lower temperatures to more homogeneous matrix deformation. Examination of the creep tests has shown a transgranular failure mode at 1400 F and an intergranular failure mode at 1600 F and 1800 F.

  12. Mixing-controlled uncertainty in long-term predictions of acid rock drainage from heterogeneous waste-rock piles

    NASA Astrophysics Data System (ADS)

    Pedretti, D.; Beckie, R. D.; Mayer, K. U.

    2015-12-01

    The chemistry of drainage from waste-rock piles at mine sites is difficult to predict because of a number of uncertainties including heterogeneous reactive mineral content, distribution of minerals, weathering rates and physical flow properties. In this presentation, we examine the effects of mixing on drainage chemistry over timescales of 100s of years. We use a 1-D streamtube conceptualization of flow in waste rocks and multicomponent reactive transport modeling. We simplify the reactive system to consist of acid-producing sulfide minerals and acid-neutralizing carbonate minerals and secondary sulfate and iron oxide minerals. We create multiple realizations of waste-rock piles with distinct distributions of reactive minerals along each flow path and examine the uncertainty of drainage geochemistry through time. The limited mixing of streamtubes that is characteristic of the vertical unsaturated flow in many waste-rock piles, allows individual flowpaths to sustain acid or neutral conditions to the base of the pile, where the streamtubes mix. Consequently, mixing and the acidity/alkalinity balance of the streamtube waters, and not the overall acid- and base-producing mineral contents, control the instantaneous discharge chemistry. Our results show that the limited mixing implied by preferential flow and the heterogeneous distribution of mineral contents lead to large uncertainty in drainage chemistry over short and medium time scales. However, over longer timescales when one of either the acid-producing or neutralizing primary phases is depleted, the drainage chemistry becomes less controlled by mixing and in turn less uncertain. A correct understanding of the temporal variability of uncertainty is key to make informed long-term decisions in mining settings regarding the management of waste material.

  13. Early Expressive Language Skills Predict Long-Term Neurocognitive Outcomes in Cochlear Implant Users: Evidence from the MacArthur–Bates Communicative Development Inventories

    PubMed Central

    Pisoni, David B.; Kronenberger, William G.; Beer, Jessica

    2016-01-01

    Purpose The objective of the present article was to document the extent to which early expressive language skills (measured using the MacArthur–Bates Communicative Development Inventories [CDI; Fenson et al., 2006]) predict long-term neurocognitive outcomes in a sample of early-implanted prelingually deaf cochlear implant (CI) users. Method The CDI was used to index the early expressive language skills of 32 pediatric CI users after an average of 1.03 years (SD = 0.56, range = 0.39–2.17) of CI experience. Long-term neurocognitive outcomes were assessed after an average of 11.32 (SD = 2.54, range = 7.08–16.52) years of CI experience. Measures of long-term neurocognitive outcomes were derived from gold-standard performance-based and questionnaire-based assessments of language, executive functioning, and academic skills. Result Analyses revealed that early expressive language skills, collected on average 1.03 years post cochlear implantation, predicted long-term language, executive functioning, and academic skills up to 16 years later. Conclusion These findings suggest that early expressive language skills, as indexed by the CDI, are clinically relevant for identifying CI users who may be at high risk for long-term neurocognitive delays and disturbances. PMID:27390923

  14. Predicting plasticity: acute context-dependent changes to vocal performance predict long-term age-dependent changes

    PubMed Central

    James, Logan S.

    2015-01-01

    Understanding the factors that predict and guide variation in behavioral change can lend insight into mechanisms of motor plasticity and individual differences in behavior. The performance of adult birdsong changes with age in a manner that is similar to rapid context-dependent changes to song. To reveal mechanisms of vocal plasticity, we analyzed the degree to which variation in the direction and magnitude of age-dependent changes to Bengalese finch song could be predicted by variation in context-dependent changes. Using a repeated-measures design, we found that variation in age-dependent changes to the timing, sequencing, and structure of vocal elements (“syllables”) was significantly predicted by variation in context-dependent changes. In particular, the degree to which the duration of intersyllable gaps, syllable sequencing at branch points, and fundamental frequency of syllables within spontaneous [undirected (UD)] songs changed over time was correlated with the degree to which these features changed from UD song to female-directed (FD) song in young-adult finches (FDyoung). As such, the structure of some temporal features of UD songs converged over time onto the structure of FDyoung songs. This convergence suggested that the FDyoung song could serve as a stable target for vocal motor plasticity. Consequently, we analyzed the stability of FD song and found that the temporal structure of FD song changed significantly over time in a manner similar to UD song. Because FD song is considered a state of heightened performance, these data suggest that age-dependent changes could reflect practice-related improvements in vocal motor performance. PMID:26311186

  15. Predicting Long-Term Outcomes for Women Physically Abused in Childhood: Contribution of Abuse Severity versus Family Environment

    ERIC Educational Resources Information Center

    Griffin, Margaret L.; Amodeo, Maryann

    2010-01-01

    Objective: Child physical abuse (CPA) has been associated with adverse adult psychosocial outcomes, although some reports describe minimal long-term effects. The search for the explanation for heterogeneous outcomes in women with CPA has led to an examination of a range of CPA-related factors, from the severity of CPA incidents to the childhood…

  16. Predicting Long-Term Outcomes for Women Sexually Abused in Childhood: Contribution of Abuse Severity Versus Family Environment

    ERIC Educational Resources Information Center

    Fassler, I.R.; Amodeo, M.; Griffin, M.L.; Clay, C.M.; Ellis, M.A.

    2005-01-01

    Objective:: Child sexual abuse (CSA) has been associated with adverse adult psychosocial outcomes, although some reports describe minimal long-term effects. The search for explanations for the heterogeneous outcomes in women with CSA has led to an examination of a range of CSA-related factors, from the severity of individual CSA incidents to the…

  17. A method to improve the stability and accuracy of ANN- and SVM-based time series models for long-term groundwater level predictions

    NASA Astrophysics Data System (ADS)

    Yoon, Heesung; Hyun, Yunjung; Ha, Kyoochul; Lee, Kang-Kun; Kim, Gyoo-Bum

    2016-05-01

    The prediction of long-term groundwater level fluctuations is necessary to effectively manage groundwater resources and to assess the effects of changes in rainfall patterns on groundwater resources. In the present study, a weighted error function approach was utilised to improve the performance of artificial neural network (ANN)- and support vector machine (SVM)-based recursive prediction models for the long-term prediction of groundwater levels in response to rainfall. The developed time series models were applied to groundwater level data from 5 groundwater-monitoring stations in South Korea. The results demonstrated that the weighted error function approach can improve the stability and accuracy of recursive prediction models, especially for ANN models. The comparison of the model performance showed that the recursive prediction performance of the SVM was superior to the performance of the ANN in this case study.

  18. Prediction of Long-term Post-operative Testosterone Replacement Requirement Based on the Pre-operative Tumor Volume and Testosterone Level in Pituitary Macroadenoma.

    PubMed

    Lee, Cheng-Chi; Chen, Chung-Ming; Lee, Shih-Tseng; Wei, Kuo-Chen; Pai, Ping-Ching; Toh, Cheng-Hong; Chuang, Chi-Cheng

    2015-11-05

    Non-functioning pituitary macroadenomas (NFPAs) are the most prevalent pituitary macroadenomas. One common symptom of NFPA is hypogonadism, which may require long-term hormone replacement. This study was designed to clarify the association between the pre-operative tumor volume, pre-operative testosterone level, intraoperative resection status and the need of long-term post-operative testosterone replacement. Between 2004 and 2012, 45 male patients with NFPAs were enrolled in this prospective study. All patients underwent transsphenoidal surgery. Hypogonadism was defined as total serum testosterone levels of <2.4 ng/mL. The tumor volume was calculated based on the pre- and post-operative magnetic resonance images. We prescribed testosterone to patients with defined hypogonadism or clinical symptoms of hypogonadism. Hormone replacement for longer than 1 year was considered as long-term therapy. The need for long-term post-operative testosterone replacement was significantly associated with larger pre-operative tumor volume (p = 0.0067), and lower pre-operative testosterone level (p = 0.0101). There was no significant difference between the gross total tumor resection and subtotal resection groups (p = 0.1059). The pre-operative tumor volume and testosterone level impact post-operative hypogonadism. By measuring the tumor volume and the testosterone level and by performing adequate tumor resection, surgeons will be able to predict post-operative hypogonadism and the need for long-term hormone replacement.

  19. Finite Element Prediction of Creep-Plastic Ratchetting and Low Cycle Creep-Fatigue for a Large SPF Tool

    NASA Astrophysics Data System (ADS)

    Deshpande, A. A.; Leen, S. B.; Hyde, T. H.

    2010-06-01

    Industrial experience shows that large superplastic forming (SPF) tools suffer from distortion due to thermal cycling, which apparently causes high temperature creep and plasticity. In addition to distortion, thermomechanical fatigue and fatigue-creep interaction can lead to cracking. The aim of this study is to predict the life-limiting thermomechanical behavior of a large SPF tool under realistic forming conditions using elastic-plastic-creep FE analyses. Nonlinear time-dependent, sequentially coupled FE analyses are performed using temperature-dependent monotonic and cyclic material data for a high-nickel, high-chromium tool material, XN40F (40% Ni and 20% Cr). The effect of monotonic and cyclic material data is compared vis-à-vis the anisothermal, elastic-plastic-stress response of the SPF tool. An uncoupled cyclic plasticity-creep material model is employed. Progressive deformation (ratchetting) is predicted locally, transverse to the predominant direction of the creep-fatigue cycling, but at the same spatial location, due to creep and cyclic plasticity, during the so-called minor cycles, which correspond to comparatively small-amplitude temperature changes associated with opening of the press doors during part loading and unloading operations.

  20. Trophic position and metabolic rate predict the long-term decay process of radioactive cesium in fish: a meta-analysis.

    PubMed

    Doi, Hideyuki; Takahara, Teruhiko; Tanaka, Kazuya

    2012-01-01

    Understanding the long-term behavior of radionuclides in organisms is important for estimating possible associated risks to human beings and ecosystems. As radioactive cesium (¹³⁷Cs) can be accumulated in organisms and has a long physical half-life, it is very important to understand its long-term decay in organisms; however, the underlying mechanisms determining the decay process are little known. We performed a meta-analysis to collect published data on the long-term ¹³⁷Cs decay process in fish species to estimate biological (metabolic rate) and ecological (trophic position, habitat, and diet type) influences on this process. From the linear mixed models, we found that 1) trophic position could predict the day of maximum ¹³⁷Cs activity concentration in fish; and 2) the metabolic rate of the fish species and environmental water temperature could predict ecological half-lives and decay rates for fish species. These findings revealed that ecological and biological traits are important to predict the long-term decay process of ¹³⁷Cs activity concentration in fish.

  1. Functional interpretation of metabolomics data as a new method for predicting long-term side effects: treatment of atopic dermatitis in infants

    PubMed Central

    Lee, Seul Ji; Woo, Sung-il; Ahn, Soo Hyun; Lim, Dong Kyu; Hong, Ji Yeon; Park, Jeong Hill; Lim, Johan; Kim, Mi-kyeong; Kwon, Sung Won

    2014-01-01

    Topical steroids are used for the treatment of primary atopic dermatitis (AD); however, their associated risk of serious complications is great due to the presence of vulnerable lesions in young children with AD. Topical calcineurin inhibitors (TCIs) are steroid-free, anti-inflammatory agents used for topical AD therapy. However, their use is prohibited in infants <2 years of age because of their carcinogenic potential. We conducted a randomized, double-blind trial to evaluate the efficacy of TCIs as a secondary AD treatment for children <2 years of age by comparing 1% pimecrolimus cream with 0.05% desonide cream. We performed urinary metabolomics to predict long-term side effects. The 1% pimecrolimus cream displayed similar efficacy and exceptional safety compared with the 0.05% desonide cream. Metabolomics-based long-term toxicity tests effectively predicted long-term side effects using short-term clinical models. This applicable method for the functional interpretation of metabolomics data sets the foundation for future studies involving the prediction of the toxicity and systemic reactions caused by long-term medication administration. PMID:25491116

  2. Slow crack propagation in glass and creep prediction

    NASA Astrophysics Data System (ADS)

    Mallet, Celine; Fortin, Jerome; Gueguen, Yves

    2013-04-01

    The context of our study is the observation of the time-dependent deformation of cracked glass. The aim of our study is to observe the slow crack propagation, to quantify it and to predict finally the creep behavior. We performed creep experiments in compaction conditions in a triaxial cell, on cracked boro-silicate glass samples. The chemical composition of the investigated glass is very close to the composition of waste vitrified packages. The matrix of the original glass (OG) is perfectly amorphous, without porosity. A few isolated air bubbles are trapped during the glass flow. Cracks are introduced in the OG through thermal shocks. Strain and acoustic emission (AE) are recorded. Several experiments are performed at different confining pressures (15 or 25 MPa), different pore fluid conditions (with argon gas, considered as the dry case, with tap water saturated porosity, or with distilled water) and different temperatures (ambiant temperature, 50oC or 80oC). Linear increase of the volumetric strain is first observed. A dilatancy increase is recorded. Note that dilatancy does not appear in constant strain rate tests. Constant stress tests show that dilatancy develops during a time interval that depends on the stress level. In addition AE rate are recorded. A non zero AE rate is an evidence of crack propagation. We use a micro-mechanical model that gives the stress intensity factor at the crack tips. This factor depends on stress and geometrical parameters (all known). An exponential law describe the rate of crack propagation, as a function of temperature, environment and applied stresses. This model allows us to predict the creep rate in glass. Assuming a constant crack aspect ratio, crack length and volumetric strain are related. The volumetric strain rate is calculated from model and compared to the data.

  3. Early response to neoadjuvant chemotherapy can help predict long-term survival in patients with cervical cancer

    PubMed Central

    Shen, Jian; Zhou, Hang; Yang, Runfeng; Wang, Lin; Liu, Jiong; Zhang, Jincheng; Sun, Haiying; Jia, Yao; Du, Xiaofang; Wang, Haoran; Deng, Song; Ding, Ting; Jiang, Jingjing; Lu, Yunping; Li, Shuang; Wang, Shixuan; Ma, Ding

    2016-01-01

    It is still controversial whether cervical cancer patients with clinical responses after neoadjuvant chemotherapy (NACT) have a better long-term survival or not. This study was designed to investigate the effect of the clinical response on the disease-free survival (DFS) of cervical cancer patients undergoing NACT. A total of 853 patients from a retrospective study were used to evaluate whether the clinical response was an indicator for the long-term response, and 493 patients from a prospective cohort study were used for further evaluation. The survival difference was detected by log-rank test, univariate and multivariate Cox regression and a pooled analysis. The log-rank test revealed that compared with non-responders, the DFS of responders was significantly higher in the retrospective data (P = 0.007). Univariate Cox regression showed that the clinical response was an indicator of long-term survival in the retrospective study (HR 1.83, 95% CI 1.18-2.85, P = 0.007). In a multivariate Cox model, the clinical response was still retained as an independent significant prognostic factor in the retrospective study (HR 1.59, 95% CI 1.01-2.50, P = 0.046). The result was also validated in the prospective data with similar results. These findings implied that the clinical response can be regarded as an independent predictor of DFS. PMID:27557523

  4. Evolution of creep-fatigue life prediction models

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.

    1991-01-01

    The evolution of high-temperature, creep-fatigue, life-prediction methods used for cyclic crack initiation is traced from inception in the late 1940s. The methods reviewed are material models as opposed to structural life prediction models. Material life models are used by both structural durability analysts and by material scientists. The latter use micromechanistic models as guidance to improve a material's crack initiation resistance. Nearly one hundred approaches and their variations have been proposed to date. This proliferation poses a problem in deciding which method is most appropriate for a given application. Approaches have been identified as being combinations of fourteen different classifications. This review is intended to aid both developers and users of high-temperature fatigue life prediction methods by providing a background from which choices can be made.

  5. Evaluating long-term relationship of protein sequence by use of D-interval conditional probability and its impact on protein structural class prediction.

    PubMed

    Gu, Fei; Chen, Hang

    2009-01-01

    To fix the large and expanding gap between sequence known proteins and structure known proteins, it is important to study on protein structural class prediction (PSCP) for its foundation and usefulness in protein structure analysis. In this paper, the d-interval conditional probability index was proposed to reflect the long-term correlation between amino acids. Based on this index, the impact of residues' long-term relationship on PSCP was analyzed. Two new information theory based algorithms were proposed and were used combining with the long-term information between residues to predict protein structural class (PSC). The dataset 5714 was tested for its low sequence similarity and high reliability. The result showed that the new index was 3-6% higher than traditional index by use of the same algorithms, and the PSCP accuracy was 4-10% improved using the new algorithms. The presented index, algorithms and the long-term relationship of residues on PSCP can be extensively applied in other sequence based protein structure analysis.

  6. Prediction of long-term cumulative incidences based on short-term parametric model for competing risks: application in early breast cancer.

    PubMed

    Cabarrou, B; Belin, L; Somda, S M; Falcou, M C; Pierga, J Y; Kirova, Y; Delord, J P; Asselain, B; Filleron, T

    2016-04-01

    Use of parametric statistical models can be a solution to reduce the follow-up period time required to estimate long-term survival. Mould and Boag were the first to use the lognormal model. Competing risks methodology seems more suitable when a particular event type is of interest than classical survival analysis. The objective was to evaluate the ability of the Jeong and Fine model to predict long-term cumulative incidence. Survival data recorded by Institut Curie (Paris) from 4761 breast cancer patients treated and followed between 1981 and 2013 were used. Long-term cumulative incidence rates predicted by the model using short-term follow-up data were compared to non-parametric estimation using complete follow-up data. 20- or 25-year cumulative incidence rates for loco-regional recurrence and distant metastasis predicted by the model using a maximum of 10 years of follow-up data had a maximum difference of around 6 % compared to non-parametric estimation. Prediction rates were underestimated for the third and composite event (contralateral or second cancer or death). Predictive ability of Jeong and Fine model on breast cancer data was generally good considering the short follow-up period time used for the estimation especially when a proportion of patient did not experience loco-regional recurrence or distant metastasis.

  7. Potential breeding distributions of U.S. birds predicted with both short-term variability and long-term average climate data.

    PubMed

    Bateman, Brooke L; Pidgeon, Anna M; Radeloff, Volker C; Flather, Curtis H; VanDerWal, Jeremy; Akçakaya, H Resit; Thogmartin, Wayne E; Albright, Thomas P; Vavrus, Stephen J; Heglund, Patricia J

    2016-12-01

    Climate conditions, such as temperature or precipitation, averaged over several decades strongly affect species distributions, as evidenced by experimental results and a plethora of models demonstrating statistical relations between species occurrences and long-term climate averages. However, long-term averages can conceal climate changes that have occurred in recent decades and may not capture actual species occurrence well because the distributions of species, especially at the edges of their range, are typically dynamic and may respond strongly to short-term climate variability. Our goal here was to test whether bird occurrence models can be predicted by either covariates based on short-term climate variability or on long-term climate averages. We parameterized species distribution models (SDMs) based on either short-term variability or long-term average climate covariates for 320 bird species in the conterminous USA and tested whether any life-history trait-based guilds were particularly sensitive to short-term conditions. Models including short-term climate variability performed well based on their cross-validated area-under-the-curve AUC score (0.85), as did models based on long-term climate averages (0.84). Similarly, both models performed well compared to independent presence/absence data from the North American Breeding Bird Survey (independent AUC of 0.89 and 0.90, respectively). However, models based on short-term variability covariates more accurately classified true absences for most species (73% of true absences classified within the lowest quarter of environmental suitability vs. 68%). In addition, they have the advantage that they can reveal the dynamic relationship between species and their environment because they capture the spatial fluctuations of species potential breeding distributions. With this information, we can identify which species and guilds are sensitive to climate variability, identify sites of high conservation value where climate

  8. Individual prediction of long-term outcome in adolescents at ultra-high risk for psychosis: Applying machine learning techniques to brain imaging data.

    PubMed

    de Wit, Sanne; Ziermans, Tim B; Nieuwenhuis, M; Schothorst, Patricia F; van Engeland, Herman; Kahn, René S; Durston, Sarah; Schnack, Hugo G

    2017-02-01

    An important focus of studies of individuals at ultra-high risk (UHR) for psychosis has been to identify biomarkers to predict which individuals will transition to psychosis. However, the majority of individuals will prove to be resilient and go on to experience remission of their symptoms and function well. The aim of this study was to investigate the possibility of using structural MRI measures collected in UHR adolescents at baseline to quantitatively predict their long-term clinical outcome and level of functioning. We included 64 UHR individuals and 62 typically developing adolescents (12-18 years old at recruitment). At six-year follow-up, we determined resilience for 43 UHR individuals. Support Vector Regression analyses were performed to predict long-term functional and clinical outcome from baseline MRI measures on a continuous scale, instead of the more typical binary classification. This led to predictive correlations of baseline MR measures with level of functioning, and negative and disorganization symptoms. The highest correlation (r = 0.42) was found between baseline subcortical volumes and long-term level of functioning. In conclusion, our results show that structural MRI data can be used to quantitatively predict long-term functional and clinical outcome in UHR individuals with medium effect size, suggesting that there may be scope for predicting outcome at the individual level. Moreover, we recommend classifying individual outcome on a continuous scale, enabling the assessment of different functional and clinical scales separately without the need to set a threshold. Hum Brain Mapp 38:704-714, 2017. © 2016 Wiley Periodicals, Inc.

  9. Creep crack growth predictions in INCO 718 using a continuum damage model

    NASA Technical Reports Server (NTRS)

    Walker, K. P.; Wilson, D. A.

    1985-01-01

    Creep crack growth tests have been carried out in compact type specimens of INCO 718 at 1200 F (649 C). Theoretical creep crack growth predictions have been carried out by incorporating a unified viscoplastic constitutive model and a continuum damage model into the ARAQUS nonlinear finite element program. Material constants for both the viscoplastic model and the creep continuum damage model were determined from tests carried out on uniaxial bar specimens of INCO 718 at 1200 F (649 C). A comparison of the theoretical creep crack growth rates obtained from the finite element predictions with the experimentally observed creep crack growth rates indicates that the viscoplastic/continuum damage model can be used to successfully predict creep crack growth in compact type specimens using material constants obtained from uniaxial bar specimens of INCO 718 at 1200 F (649 C).

  10. A creep cavity growth model for creep-fatigue life prediction of a unidirectional W/Cu composite

    NASA Technical Reports Server (NTRS)

    Kim, Young-Suk; Verrilli, Michael J.; Halford, Gary R.

    1992-01-01

    A microstructural model was developed to predict creep-fatigue life in a (0)(sub 4), 9 volume percent tungsten fiber-reinforced copper matrix composite at the temperature of 833 K. The mechanism of failure of the composite is assumed to be governed by the growth of quasi-equilibrium cavities in the copper matrix of the composite, based on the microscopically observed failure mechanisms. The methodology uses a cavity growth model developed for prediction of creep fracture. Instantaneous values of strain rate and stress in the copper matrix during fatigue cycles were calculated and incorporated in the model to predict cyclic life. The stress in the copper matrix was determined by use of a simple two-bar model for the fiber and matrix during cyclic loading. The model successfully predicted the composite creep-fatigue life under tension-tension cyclic loading through the use of this instantaneous matrix stress level. Inclusion of additional mechanisms such as cavity nucleation, grain boundary sliding, and the effect of fibers on matrix-stress level would result in more generalized predictions of creep-fatigue life.

  11. Metabolic Profiling of Human Long-Term Liver Models and Hepatic Clearance Predictions from In Vitro Data Using Nonlinear Mixed-Effects Modeling.

    PubMed

    Kratochwil, Nicole A; Meille, Christophe; Fowler, Stephen; Klammers, Florian; Ekiciler, Aynur; Molitor, Birgit; Simon, Sandrine; Walter, Isabelle; McGinnis, Claudia; Walther, Johanna; Leonard, Brian; Triyatni, Miriam; Javanbakht, Hassan; Funk, Christoph; Schuler, Franz; Lavé, Thierry; Parrott, Neil J

    2017-03-01

    Early prediction of human clearance is often challenging, in particular for the growing number of low-clearance compounds. Long-term in vitro models have been developed which enable sophisticated hepatic drug disposition studies and improved clearance predictions. Here, the cell line HepG2, iPSC-derived hepatocytes (iCell®), the hepatic stem cell line HepaRG™, and human hepatocyte co-cultures (HμREL™ and HepatoPac®) were compared to primary hepatocyte suspension cultures with respect to their key metabolic activities. Similar metabolic activities were found for the long-term models HepaRG™, HμREL™, and HepatoPac® and the short-term suspension cultures when averaged across all 11 enzyme markers, although differences were seen in the activities of CYP2D6 and non-CYP enzymes. For iCell® and HepG2, the metabolic activity was more than tenfold lower. The micropatterned HepatoPac® model was further evaluated with respect to clearance prediction. To assess the in vitro parameters, pharmacokinetic modeling was applied. The determination of intrinsic clearance by nonlinear mixed-effects modeling in a long-term model significantly increased the confidence in the parameter estimation and extended the sensitive range towards 3% of liver blood flow, i.e., >10-fold lower as compared to suspension cultures. For in vitro to in vivo extrapolation, the well-stirred model was used. The micropatterned model gave rise to clearance prediction in man within a twofold error for the majority of low-clearance compounds. Further research is needed to understand whether transporter activity and drug metabolism by non-CYP enzymes, such as UGTs, SULTs, AO, and FMO, is comparable to the in vivo situation in these long-term culture models.

  12. Creep Life Prediction of Ceramic Components Using the Finite Element Based Integrated Design Program (CARES/Creep)

    NASA Technical Reports Server (NTRS)

    Jadaan, Osama M.; Powers, Lynn M.; Gyekenyesi, John P.

    1997-01-01

    The desirable properties of ceramics at high temperatures have generated interest in their use for structural applications such as in advanced turbine systems. Design lives for such systems can exceed 10,000 hours. Such long life requirements necessitate subjecting the components to relatively low stresses. The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this work is to present a design methodology for predicting the lifetimes of structural components subjected to multiaxial creep loading. This methodology utilizes commercially available finite element packages and takes into account the time varying creep stress distributions (stress relaxation). In this methodology, the creep life of a component is divided into short time steps, during which, the stress and strain distributions are assumed constant. The damage, D, is calculated for each time step based on a modified Monkman-Grant creep rupture criterion. For components subjected to predominantly tensile loading, failure is assumed to occur when the normalized accumulated damage at any point in the component is greater than or equal to unity.

  13. Prediction of creep-rupture life of unidirectional titanium matrix composites subjected to transverse loading

    SciTech Connect

    John, R.; Khobaib, M.; Smith, P.R.

    1996-10-01

    Titanium matrix composites (TMCs) incorporating unidirectional fiber reinforcement are considered as enabling materials technology for advanced engines which require high specific strength and elevated temperature capability. The resistance of unidirectional TMCs to deformation under longitudinally applied sustained loading at elevated temperatures has been well documented. Many investigators have shown that the primary weakness of the unidirectional TMC is its susceptibility to failure under very low transverse loads, especially under sustained loading. Hence, a reliable model is required to predict the creep-rupture life of TMCs subjected to different transverse stress levels over a wide range of temperatures. In this article, the authors propose a model to predict the creep-rupture life of unidirectional TMC subjected to transverse loading based on the creep-rupture life of unidirectional TMC subjected to transverse loading based on the creep-rupture behavior of the corresponding fiberless matrix. The model assumes that during transverse loading, the effective load-carrying matrix ligament along a row of fibers controls the creep-rupture strength and the fibers do not contribute to the creep resistance of the composite. The proposed model was verified using data obtained from different TMC fabricated using three matrix compositions, which exhibited distinctly different types of creep behavior. The results show that the creep-rupture life of the transverse TMC decreases linearly with increasing ratio of the fiber diameter to the ply thickness. The creep-rupture life is also predicted to be independent of fiber spacing along the length of the specimen.

  14. Predicting ecosystem carbon balance in a warming Arctic: the importance of long-term thermal acclimation potential and inhibitory effects of light on respiration.

    PubMed

    McLaughlin, Blair C; Xu, Cheng-Yuan; Rastetter, Edward B; Griffin, Kevin L

    2014-06-01

    The carbon balance of Arctic ecosystems is particularly sensitive to global environmental change. Leaf respiration (R), a temperature-dependent key process in determining the carbon balance, is not well-understood in Arctic plants. The potential for plants to acclimate to warmer conditions could strongly impact future global carbon balance. Two key unanswered questions are (1) whether short-term temperature responses can predict long-term respiratory responses to growth in elevated temperatures and (2) to what extent the constant daylight conditions of the Arctic growing season inhibit leaf respiration. In two dominant Arctic species Eriophorum vaginatum (tussock grass) and Betula nana (woody shrub), we assessed the extent of respiratory inhibition in the light (RL/RD), respiratory response to short-term temperature change, and respiratory acclimation to long-term warming treatments. We found that R of both species is strongly inhibited by light (averaging 35% across all measurement temperatures). In E. vaginatum both RL and RD acclimated to the long-term warming treatment, reducing the magnitude of respiratory response relative to the short-term response to temperature increase. In B. nana, both RL and RD responded to short-term temperature increase but showed no acclimation to the long-term warming. The ability to predict plant respiratory response to global warming with short-term temperature responses will depend on species-specific acclimation potential and the differential response of RL and RD to temperature. With projected woody shrub encroachment in Arctic tundra and continued warming, changing species dominance between these two functional groups, may impact ecosystem respiratory response and carbon balance.

  15. Biochemical Response to Androgen Deprivation Therapy Before External Beam Radiation Therapy Predicts Long-term Prostate Cancer Survival Outcomes

    SciTech Connect

    Zelefsky, Michael J.; Gomez, Daniel R.; Polkinghorn, William R.; Pei, Xin; Kollmeier, Marisa

    2013-07-01

    Purpose: To determine whether the response to neoadjuvant androgen deprivation therapy (ADT) defined by a decline in prostate-specific antigen (PSA) to nadir values is associated with improved survival outcomes after external beam radiation therapy (EBRT) for prostate cancer. Methods and Materials: One thousand forty-five patients with localized prostate cancer were treated with definitive EBRT in conjunction with neoadjuvant and concurrent ADT. A 6-month course of ADT was used (3 months during the neoadjuvant phase and 2 to 3 months concurrently with EBRT). The median EBRT prescription dose was 81 Gy using a conformal-based technique. The median follow-up time was 8.5 years. Results: The 10-year PSA relapse-free survival outcome among patients with pre-radiation therapy PSA nadirs of ≤0.3 ng/mL was 74.3%, compared with 57.7% for patients with higher PSA nadir values (P<.001). The 10-year distant metastases-free survival outcome among patients with pre-radiation therapy PSA nadirs of ≤0.3 ng/mL was 86.1%, compared with 78.6% for patients with higher PSA nadir values (P=.004). In a competing-risk analysis, prostate cancer-related deaths were also significantly reduced among patients with pre-radiation therapy PSA nadirs of <0.3 ng/mL compared with higher values (7.8% compared with 13.7%; P=.009). Multivariable analysis demonstrated that the pre-EBRT PSA nadir value was a significant predictor of long-term biochemical tumor control, distant metastases-free survival, and cause-specific survival outcomes. Conclusions: Pre-radiation therapy nadir PSA values of ≤0.3 ng/mL after neoadjuvant ADT were associated with improved long-term biochemical tumor control, reduction in distant metastases, and prostate cancer-related death. Patients with higher nadir values may require alternative adjuvant therapies to improve outcomes.

  16. Metabolic syndrome predicts long-term mortality in subjects without established diabetes mellitus in asymptomatic Korean population

    PubMed Central

    Won, Ki-Bum; Chang, Hyuk-Jae; Han, Donghee; Sung, Jidong; Choi, Su-Yeon

    2016-01-01

    Abstract Despite the different features of diabetes mellitus (DM) in Asian populations compared with Western populations, the impact of metabolic syndrome (MetS) on long-term mortality according to DM status has not yet been elucidated in the Asian population. After performing 1:1 propensity score matching (PSM) using clinical variables including age, gender, smoking, and individual MetS components between DM and non-DM subjects from the data of the Korea Initiatives on Coronary Artery Calcification registry, mortality was evaluated according to DM and MetS in 14,956 asymptomatic Korean subjects. The mean follow-up duration was 53.1 months (interquartile range: 33–80). The overall prevalence of MetS was 60%. DM subjects had higher mortality compared with non-DM subjects (1.2% vs 0.7%, respectively; P = 0.001); the cumulative mortality by Kaplan–Meier analysis was higher in DM subjects than in non-DM subjects (log-rank P = 0.001). DM increased the risk of mortality in PSM participants (hazard ratio [HR] 1.74; P = 0.001). In non-DM subjects, MetS (HR 2.32) and one of its components, central obesity (HR 1.97), were associated with an increased risk of mortality (both P < 0.05). In contrast, there was no significant difference in the risk of mortality according to MetS or its components in DM subjects. After adjusting for confounding risk factors, it was shown that MetS independently increased the risk of mortality in non-DM subjects. Compared with non-DM subjects, DM subjects have an increased risk of long-term mortality among PSM participants. MetS appears to have an independent impact on mortality in subjects without established DM among the asymptomatic Korean population. Our results may not be applicable to the whole subjects with MetS because the PSM using MetS components was performed between subjects with and without DM which was very high risk for adverse clinical events. PMID:27930521

  17. Long-term prediction of groundwater recharge by climate changes in the Gosan agricultural area, Jeju Island of South Korea

    NASA Astrophysics Data System (ADS)

    Koh, E. H.; Kaown, D.; Lee, K. K.

    2015-12-01

    Evaluation of long-term changes in groundwater recharge due to the climate changes is needed to secure the sustainable use of grounwater. In Jeju Island, which is composed of various formations of porous volcanic rocks, groundwater is a sole resource for water supply because of its hydrogeological characteristics. Therefore, preservation of the groundwater resource is an essential issue in the island. Prior to establishing a management plan for maintaining the groundwater resources in Jeju Island, long-term estimation of influencing factors are necessary. The Gosan study area is located in the western part of the island, where extensive agricultural activity has been performed and groundwater is a main source of supply for watering crops. In this study, we estimated the recharge changes for 100 years (2000~2099) in the Gosan agricultural area based on two climate change scenarios (RCP 4.5 and RCP 8.5) by using the HELP3 (Hydrologic Evaluation of Landfill Performance) program. The estimated component of water budget in this study are as follows (averaged in 2000~2014), precipitation: 1.28x108 m3/yr; ET: 6.49x107 m3/yr; runoff: 5.84x106 m3/yr; and recharge: 5.27x107 m3/yr. Over the 100 years of the estimated period, precipitation will have a highest increase among other meteorological parameters to be 6.16x109 m3 (RCP4.5) and 6.34 x109 m3 (RCP8.5). Increase in recharge by RCP8.5 scenario (2.75 x109 m3) will be less than that by RCP4.5 (2.77x109 m3) because ET by RCP 8.5 (ET: 3.34x109 m3; runoff: 2.27x108 m3) is estimated to be higher than ET by RCP4.5 (ET: 3.15x109 m3; runoff: 2.35x108 m3). Jeju volcanic island is known to have higher recharge proportions to the precipitation due to the distributed highly porous volcanic rocks. Therefore, variations in precipitation by climate changes would greatly affect the groundwater resource of the island. Acknowledgement: This work was supported by the research project of "Advanced Technology for

  18. Historical Prediction Modeling Approach for Estimating Long-Term Concentrations of PM2.5 in Cohort Studies before the 1999 Implementation of Widespread Monitoring

    PubMed Central

    Kim, Sun-Young; Olives, Casey; Sheppard, Lianne; Sampson, Paul D.; Larson, Timothy V.; Keller, Joshua P.; Kaufman, Joel D.

    2016-01-01

    Introduction: Recent cohort studies have used exposure prediction models to estimate the association between long-term residential concentrations of fine particulate matter (PM2.5) and health. Because these prediction models rely on PM2.5 monitoring data, predictions for times before extensive spatial monitoring present a challenge to understanding long-term exposure effects. The U.S. Environmental Protection Agency (EPA) Federal Reference Method (FRM) network for PM2.5 was established in 1999. Objectives: We evaluated a novel statistical approach to produce high-quality exposure predictions from 1980 through 2010 in the continental United States for epidemiological applications. Methods: We developed spatio-temporal prediction models using geographic predictors and annual average PM2.5 data from 1999 through 2010 from the FRM and the Interagency Monitoring of Protected Visual Environments (IMPROVE) networks. Temporal trends before 1999 were estimated by using a) extrapolation based on PM2.5 data in FRM/IMPROVE, b) PM2.5 sulfate data in the Clean Air Status and Trends Network, and c) visibility data across the Weather Bureau Army Navy network. We validated the models using PM2.5 data collected before 1999 from IMPROVE, California Air Resources Board dichotomous sampler monitoring (CARB dichot), the Children’s Health Study (CHS), and the Inhalable Particulate Network (IPN). Results: In our validation using pre-1999 data, the prediction model performed well across three trend estimation approaches when validated using IMPROVE and CHS data (R2 = 0.84–0.91) with lower R2 values in early years. Model performance using CARB dichot and IPN data was worse (R2 = 0.00–0.85) most likely because of fewer monitoring sites and inconsistent sampling methods. Conclusions: Our prediction modeling approach will allow health effects estimation associated with long-term exposures to PM2.5 over extended time periods ≤ 30 years. Citation: Kim SY, Olives C, Sheppard L, Sampson PD

  19. Creep behaviour and creep mechanisms of normal and healing ligaments

    NASA Astrophysics Data System (ADS)

    Thornton, Gail Marilyn

    . Similarly, ligament autografts had persistently abnormal creep behaviour and creep recovery after 2 years likely due to infiltration by scar tissue. Short-term immobilization of autografts had long-term detrimental consequences perhaps due to re-injury of the graft at remobilization. Treatments that restore normal properties to these mechanistic factors in order to control creep would improve joint healing by restoring joint kinematics and maintaining normal joint loading.

  20. Increase in posterior alpha activity during rehearsal predicts successful long-term memory formation of word sequences.

    PubMed

    Meeuwissen, Esther B; Takashima, Atsuko; Fernández, Guillén; Jensen, Ole

    2011-12-01

    It is becoming increasingly clear that demanding cognitive tasks rely on an extended network engaging task-relevant areas and, importantly, disengaging task-irrelevant areas. Given that alpha activity (8-12 Hz) has been shown to reflect the disengagement of task-irrelevant regions in attention and working memory tasks, we here ask if alpha activity plays a related role for long-term memory formation. Subjects were instructed to encode and maintain the order of word sequences while the ongoing brain activity was recorded using magnetoencephalography (MEG). In each trial, three words were presented followed by a 3.4 s rehearsal interval. Considering the good temporal resolution of MEG this allowed us to investigate the word presentation and rehearsal interval separately. The sequences were grouped in trials where word order either could be tested immediately (working memory trials; WM) or later (LTM trials) according to instructions. Subjects were tested on their ability to retrieve the order of the three words. The data revealed that alpha power in parieto-occipital regions was lower during word presentation compared to rehearsal. Our key finding was that parieto-occipital alpha power during the rehearsal period was markedly stronger for successfully than unsuccessfully encoded LTM sequences. This subsequent memory effect demonstrates that high posterior alpha activity creates an optimal brain state for successful LTM formation possibly by actively reducing parieto-occipital activity that might interfere with sequence encoding.

  1. Righting Reflex Predicts Long-Term Histological and Behavioral Outcomes in a Closed Head Model of Traumatic Brain Injury

    PubMed Central

    Grin’kina, Natalia M.; Li, Yang; Haber, Margalit; Sangobowale, Michael; Nikulina, Elena; Le’Pre, Charm; El Sehamy, Alexander M.; Dugue, Rachelle; Ho, Johnson S.

    2016-01-01

    Blunt impact produces a heterogeneous brain injury in people and in animal models of traumatic brain injury. We report that a single closed head impact to adult C57/BL6 mice produced two injury syndromes (CHI-1 and CHI-2). CHI-1 mice spontaneously reinitiated breathing after injury while CHI-2 mice had prolonged apnea and regained breathing only after cardiopulmonary resuscitation and supplementation of 100% O2. The CHI-1 group significantly regained righting reflex more rapidly than the CHI-2 group. At 7 days post-injury, CHI-1, but not CHI-2 mice, acquired but had no long-term retention of an active place avoidance task. The behavioral deficits of CHI-1 and CHI-2 mice were retained one-month after the injury. CHI-1 mice had loss of hippocampal neurons and localized white matter injury at one month after injury. CHI-2 had a larger loss of hippocampal neurons and more widespread loss of myelin and axons. High-speed videos made during the injury were followed by assessment of breathing and righting reflex. These videos show that CHI-2 mice experienced a larger vertical g-force than CHI-1 mice. Time to regain righting reflex in CHI-2 mice significantly correlated with vertical g-force. Thus, physiological responses occurring immediately after injury can be valuable surrogate markers of subsequent behavioral and histological deficits. PMID:27657499

  2. Methodology to predict the number of forced outages due to creep failure

    SciTech Connect

    Palermo, J.V. Jr.

    1996-12-31

    All alloy metals at a temperature above 950 degrees Fahrenheit experience creep damage. Creep failures in boiler tubes usually begin after 25 to 40 years of operation. Since creep damage is irreversible, the only remedy is to replace the tube sections. By predicting the number of failures per year, the utility can make the best economic decision concerning tube replacement. This paper describes a methodology to calculate the number of forced outages per yea due to creep failures. This methodology is particularly useful to utilities that have boilers that have at least 25 years of operation.

  3. Development of a constitutive model for creep and life prediction of advanced silicon nitride ceramics

    SciTech Connect

    Ding, J.L.; Liu, K.C.; Brinkman, C.R.

    1992-12-31

    A constitutive model capable of describing deformation and predicting rupture life was developed for high temperature ceramic materials under general thermal-mechanical loading conditions. The model was developed based on the deformation and fracture behavior observed from a systematic experimental study on an advanced silicon nitride (Si{sub 3}N{sub 4}) ceramic material. Validity of the model was evaluated with reference to creep and creep rupture data obtained under constant and stepwise-varied loading conditions, including the effects of annealing on creep and creep rupture behavior.

  4. Creep fatigue life prediction for engine hot section materials (isotropic)

    NASA Technical Reports Server (NTRS)

    Moreno, V.

    1983-01-01

    The Hot Section Technology (HOST) program, creep fatigue life prediction for engine hot section materials (isotropic), is reviewed. The program is aimed at improving the high temperature crack initiation life prediction technology for gas turbine hot section components. Significant results include: (1) cast B1900 and wrought IN 718 selected as the base and alternative materials respectively; (2) fatigue test specimens indicated that measurable surface cracks appear early in the specimen lives, i.e., 15% of total life at 871 C and 50% of life at 538 c; (3) observed crack initiation sites are all surface initiated and are associated with either grain boundary carbides or local porosity, transgrannular cracking is observed at the initiation site for all conditions tested; and (4) an initial evaluation of two life prediction models, representative of macroscopic (Coffin-Mason) and more microscopic (damage rate) approaches, was conducted using limited data generated at 871 C and 538 C. It is found that the microscopic approach provides a more accurate regression of the data used to determine crack initiation model constants, but overpredicts the effect of strain rate on crack initiation life for the conditions tested.

  5. An alternative to fully coupled reactive transport simulations for long-term prediction of chemical reactions in complex geological systems

    NASA Astrophysics Data System (ADS)

    De Lucia, Marco; Kempka, Thomas; Kühn, Michael

    2014-05-01

    Fully-coupled reactive transport simulations involving multiphase hydrodynamics and chemical reactions in heterogeneous settings are extremely challenging from a computational point of view. This often leads to oversimplification of the investigated system: coarse spatial discretization, to keep the number of elements in the order of few thousands; simplified chemistry, disregarding many potentially important reactions. A novel approach for coupling non-reactive hydrodynamic simulations with the outcome of single batch geochemical simulations was therefore introduced to assess the potential long-term mineral trapping at the Ketzin pilot site for underground CO2 storage in Germany [1],[2]. The advantage of the coupling is the ability to use multi-million grid non-reactive hydrodynamics simulations on one side and few batch 0D geochemical simulations on the other, so that the complexity of both systems does not need to be reduced. This contribution shows the approach which was taken to validate this simplified coupling scheme. The procedure involved batch simulations of the reference geochemical model, then performing both non-reactive and fully coupled 1D and 3D reactive transport simulations and finally applying the simplified coupling scheme based on the non-reactive and geochemical batch model. The TOUGHREACT/ECO2N [3] simulator was adopted for the validation. The degree of refinement of the spatial grid and the complexity and velocity of the mineral reactions, along with a cut-off value for the minimum concentration of dissolved CO2 allowed to originate precipitates in the simplified approach were found out to be the governing parameters for the convergence of the two schemes. Systematic discrepancies between the approaches are not reducible, simply because there is no feedback between chemistry and hydrodynamics, and can reach 20 % - 30 % in unfavourable cases. However, even such discrepancy is completely acceptable, in our opinion, given the amount of

  6. Impaired Global Right Ventricular Longitudinal Strain Predicts Long-Term Adverse Outcomes in Patients with Pulmonary Arterial Hypertension

    PubMed Central

    Park, Jae-Hyeong; Park, Margaret M.; Farha, Samar; Sharp, Jacqueline; Lundgrin, Erika; Comhair, Suzy; Tang, Wai Hong; Erzurum, Serpil C.

    2015-01-01

    Background New 2-dimensional strain echocardiography enables quantification of right ventricular (RV) mechanics by assessing global longitudinal strain of RV (GLSRV) in patients with pulmonary arterial hypertension (PAH). However, the prognostic significance of impaired GLSRV is unclear in these patients. Methods Comprehensive echocardiography was performed in 51 consecutive PAH patients without atrial fibrillation (40 females, 48 ± 14 years old) with long-term follow-up. GLSRV was measured with off-line with velocity vector imaging (VVI, Siemens Medical System, Mountain View, CA, USA). Results GLSRV showed significant correlation with RV fractional area change (r = -0.606, p < 0.001), tricuspid annular plane systolic excursion (r = -0.579, p < 0.001), and RV Tei index (r = 0.590, p < 0.001). It showed significant correlations with pulmonary vascular resistance (r = 0.469, p = 0.001) and B-natriuretic peptide concentration (r = 0.351, p = 0.012). During a clinical followup time (45 ± 15 months), 20 patients experienced one or more adverse events (12 death, 2 lung transplantation, and 15 heart failure hospitalization). After multivariate analysis, age [hazard ratio (HR) = 2.343, p = 0.040] and GLSRV (HR = 2.122, p = 0.040) were associated with adverse clinical events. Age (HR = 3.200, p = 0.016) and GLSRV (HR = 2.090, p = 0.042) were also significant predictors of death. Impaired GLSRV (≥ -15.5%) was associated with lower event-free survival (HR = 4.906, p = 0.001) and increased mortality (HR = 8.842, p = 0.005). Conclusion GLSRV by VVI showed significant correlations with conventional echocardiographic parameters indicating RV systolic function. Lower GLSRV (≥ -15.5%) was significantly associated with presence of adverse clinical events and deaths in PAH patients. PMID:26140151

  7. A Meta-analysis to Evaluate the Predictive Validity of the Braden Scale for Pressure Ulcer Risk Assessment in Long-term Care.

    PubMed

    Chen, Hong-Lin; Shen, Wang-Qin; Liu, Peng

    2016-09-01

    Although it is among the most commonly used pressure ulcer risk assessment tools, the Braden Scale may lack strong predictive validity when used in the long-term care setting. A meta-analysis was conducted of English-language articles published in the PubMed database and Web of Science from the indices' inception through July 2015 to assess the predictive validity of the Braden Scale for pressure ulcers in long-term care residents. Search terms included pressure ulcer, pressure sore, bedsore, decubitus, long-term care, nursing home, skilled nursing facility, hospice, and Braden. Data extracted from the publications included sample and setting characteristics and predictive value indices. The pooled sensitivities, specificities, diagnostic odds ratios (DOR), and constructed summary receiver operating characteristic (SROC) curves were calculated. Eight studies (2 prospective cohorts and 6 cross-sectional studies) with 41 489 residents met selection criteria for inclusion in the analysis. The pooled sensitivity and specificity were 0.80 (95% CI: 0.79-0.81) and 0.42 (95% CI: 0.42-0.43), respectively, yielding a combined DOR of 5.66 (95% CI: 3.77-8.48). The area under the ROC curve (AUC) was 0.7686 ± 0.0478 (95% CI: 0.6749-0.8623), and the overall diagnostic accuracy (Q*) was 0.7090 ± 0.0402 (95% CI: 0.6302-0.7878). Significant heterogeneity was noted among the included studies; Q value was 302.54 (P = 0.000), and I2 for pooled sensitivity, pooled specificity, and pooled DOR was 97.4%, 98.7% and 96.4%, respectively. Meta-regression analysis showed no heterogeneity was noted among Braden scale cut-offs (P = 0.123) and pressure ulcer prevalence P = 0.547). The evidence showed the Braden Scale has moderate predictive validity and low predictive specificity for pressure ulcers in long-term care residents. The development and testing of new risk assessment scales for this population is warranted.

  8. General inattentiveness is a long-term reliable trait independently predictive of psychological health: Danish validation studies of the Mindful Attention Awareness Scale.

    PubMed

    Jensen, Christian Gaden; Niclasen, Janni; Vangkilde, Signe Allerup; Petersen, Anders; Hasselbalch, Steen Gregers

    2016-05-01

    The Mindful Attention Awareness Scale (MAAS) measures perceived degree of inattentiveness in different contexts and is often used as a reversed indicator of mindfulness. MAAS is hypothesized to reflect a psychological trait or disposition when used outside attentional training contexts, but the long-term test-retest reliability of MAAS scores is virtually untested. It is unknown whether MAAS predicts psychological health after controlling for standardized socioeconomic status classifications. First, MAAS translated to Danish was validated psychometrically within a randomly invited healthy adult community sample (N = 490). Factor analysis confirmed that MAAS scores quantified a unifactorial construct of excellent composite reliability and consistent convergent validity. Structural equation modeling revealed that MAAS scores contributed independently to predicting psychological distress and mental health, after controlling for age, gender, income, socioeconomic occupational class, stressful life events, and social desirability (β = 0.32-.42, ps < .001). Second, MAAS scores showed satisfactory short-term test-retest reliability in 100 retested healthy university students. Finally, MAAS sample mean scores as well as individuals' scores demonstrated satisfactory test-retest reliability across a 6 months interval in the adult community (retested N = 407), intraclass correlations ≥ .74. MAAS scores displayed significantly stronger long-term test-retest reliability than scores measuring psychological distress (z = 2.78, p = .005). Test-retest reliability estimates did not differ within demographic and socioeconomic strata. Scores on the Danish MAAS were psychometrically validated in healthy adults. MAAS's inattentiveness scores reflected a unidimensional construct, long-term reliable disposition, and a factor of independent significance for predicting psychological health. (PsycINFO Database Record

  9. Combined baseline strain dyssynchrony index and its acute reduction predicts mid-term left ventricular reverse remodeling and long-term outcome after cardiac resynchronization therapy.

    PubMed

    Tatsumi, Kazuhiro; Tanaka, Hidekazu; Matsumoto, Kensuke; Miyoshi, Tatsuya; Hiraishi, Mana; Tsuji, Takayuki; Kaneko, Akihiro; Ryo, Keiko; Fukuda, Yuko; Norisada, Kazuko; Onishi, Tetsuari; Yoshida, Akihiro; Kawai, Hiroya; Hirata, Ken-ichi

    2014-04-01

    The objective of this study was to test the hypothesis that combining assessment of baseline radial strain dyssynchrony index (SDI), that expressed both left ventricular (LV) dyssynchrony and residual myocardial contractility, and of acute changes in this index can yield more accurate prediction of mid-term responders and long-term outcome after cardiac resynchronization therapy (CRT). Radial SDI for 75 CRT patients was calculated as the average difference between peak and end-systolic speckle tracking strain from 6 segments of the mid-LV short-axis view before and 8 ± 2 days after CRT. Mid-term responder was defined as ≥ 15% decrease in LV end-systolic volume 6 ± 2 months after CRT. Long-term outcome was tracked over 5 years. Baseline radial SDI ≥ 6.5% is considered predictive of responder and favorable outcome, as previously reported. Acute reduction in radial SDI ≥ 1.5% was found to be the best predictor of mid-term responders with CRT. Furthermore, patients with acute reductions in radial SDI ≥1.5% were associated with a significantly more favorable long-term outcome after CRT than those with radial SDI <1.5% (log rank P < 0.001). An important findings were that baseline radial SDI ≥6.5% and acute reductions in radial SDI ≥ 1.5% in 42 patients were associated with the highest event-free survival rate of 92%, whereas, 21 patients corresponding values of <6.5% and <1.5% were associated with low event-free survival rate of 46% (log rank P < 0.001). Combined assessment of baseline radial SDI and its acute reduction after CRT may have clinical implications for predicting responders and thus patients' care.

  10. The Differential Effects of Abuse Characteristics and Attachment in the Prediction of Long-Term Effects of Sexual Abuse.

    ERIC Educational Resources Information Center

    Alexander, Pamela C.

    1993-01-01

    Female incest survivors (n=112) completed several inventories and checklists to measure sexual abuse severity and adult attachment. Analyses indicated that sexual abuse characteristics predicted depression, intrusive thoughts, and memory avoidance. Adult attachment, particularly a lack of secure attachment, predicted memory avoidance, and also…

  11. Predicting dislocation climb and creep from explicit atomistic details.

    PubMed

    Kabir, Mukul; Lau, Timothy T; Rodney, David; Yip, Sidney; Van Vliet, Krystyn J

    2010-08-27

    Here we report kinetic Monte Carlo simulations of dislocation climb in heavily deformed, body-centered cubic iron comprising a supersaturation of vacancies. This approach explicitly incorporates the effect of nonlinear vacancy-dislocation interaction on vacancy migration barriers as determined from atomistic calculations, and enables observations of diffusivity and climb over time scales and temperatures relevant to power-law creep. By capturing the underlying microscopic physics, the calculated stress exponents for steady-state creep rates agree quantitatively with the experimentally measured range, and qualitatively with the stress dependence of creep activation energies.

  12. Long-term predictability of soil moisture dynamics at the global scale: Persistence versus large-scale drivers

    NASA Astrophysics Data System (ADS)

    Nicolai-Shaw, Nadine; Gudmundsson, Lukas; Hirschi, Martin; Seneviratne, Sonia I.

    2016-08-01

    Here we investigate factors that influence the long lead time predictability of soil moisture variability using standard statistical methods. As predictors we first consider soil moisture persistence only, using two independent global soil moisture data sets. In a second step we include three teleconnection indices indicative of the main northern, tropical, and southern atmospheric modes, i.e., the North Atlantic Oscillation (NAO), the Southern Oscillation Index (SOI), and the Antarctic Oscillation (AAO). For many regions results show significant skill in predicting soil moisture variability with lead times up to 5 months. Soil moisture persistence plays a key role at monthly to subseasonal time scales. With increasing lead times large-scale atmospheric drivers become more important, and areas influenced by teleconnection indices show higher predictability. This long lead time predictability of soil moisture may help to improve early warning systems for important natural hazards, such as heat waves, droughts, wildfires, and floods.

  13. Inflammatory Activity on Natalizumab Predicts Short-Term but Not Long-Term Disability in Multiple Sclerosis

    PubMed Central

    Dahdaleh, Samer; Malik, Omar; Jones, Brynmor; Nicholas, Richard

    2017-01-01

    Background In people with multiple sclerosis treated with interferon-beta or glatiramer acetate, new MRI lesions and relapses during the first year of treatment predict a poor prognosis. Objective To study this association in those receiving natalizumab. Methods Data were collected on relapses, new MRI activity, and Modified Rio Score after initiation of natalizumab in an observational cohort of 161 patients with high baseline disability. These were correlated with Expanded Disability Status Scale (EDSS) progression at years 1, 2, 3, and 3–7 after treatment initiation, versus pre-treatment baseline. Results 46/161 patients had a relapse in the first year and 44/161 had EDSS progression by year 2. Relapses and Modified Rio Score in the first year of treatment predicted EDSS progression at year 1 and 2 after treatment initiation. However, this effect disappeared with longer follow-up. Paradoxically, there was a trend towards inflammatory activity on treatment (first year Modified Rio Score, relapses, and MRI activity) predicting a lower risk of EDSS progression by years 3–7, although this did not reach statistical significance. Those with and without EDSS progression did not differ in baseline age, EDSS, or pre-treatment relapse rate. Relapses in year 0–1 predicted further relapses in years 1–3. Conclusions Breakthrough inflammatory activity after natalizumab treatment is predictive of short-term outcome measures of relapses or EDSS progression, but does not predict longer term EDSS progression, in this cohort with high baseline disability. PMID:28081190

  14. Creep fatigue life prediction for engine hot section materials (isotropic)

    NASA Technical Reports Server (NTRS)

    Nelson, R. S.; Levan, G. W.; Harvey, P. R.

    1992-01-01

    This Final Report covers the activities completed under the optional program of the NASA HOST Contract, NAS3-23288. The initial effort of the optional program was report-in NASA CR189221, which consisted of high temperature strain controlled fatigue tests to study the effects of thermomechanical fatigue, multiaxial loading, reactive environments, and imposed stresses. The baseline alloy used in the tests included B1900+Hf (with or without coating) and wrought INCO 718. Tests conducted on B1900+Hf included environmental tests using various atmospheres (75 psig oxygen, purified argon, or block exposures) and specimen tests of wrought INCO 718 included tensile, creep, stress rupture, TMF, multiaxial, and mean stress tests. Results of these testings were used to calibrate a CDA model for INCO 718 alloy and to develop modifications or corrections to the CDA model to handle additional failure mechanisms. The Socie parameter was found to provide the best correlation for INCO multiaxial loading. Microstructural evaluations consisting of optical, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques, and surface replication techniques to determine crack initiation lives provided data which were used to develop life prediction models.

  15. Performance of a Predictive Model for Long-Term Hemoglobin Response to Darbepoetin and Iron Administration in a Large Cohort of Hemodialysis Patients.

    PubMed

    Barbieri, Carlo; Bolzoni, Elena; Mari, Flavio; Cattinelli, Isabella; Bellocchio, Francesco; Martin, José D; Amato, Claudia; Stopper, Andrea; Gatti, Emanuele; Macdougall, Iain C; Stuard, Stefano; Canaud, Bernard

    2016-01-01

    Anemia management, based on erythropoiesis stimulating agents (ESA) and iron supplementation, has become an increasingly challenging problem in hemodialysis patients. Maintaining hemodialysis patients within narrow hemoglobin targets, preventing cycling outside target, and reducing ESA dosing to prevent adverse outcomes requires considerable attention from caregivers. Anticipation of the long-term response (i.e. at 3 months) to the ESA/iron therapy would be of fundamental importance for planning a successful treatment strategy. To this end, we developed a predictive model designed to support decision-making regarding anemia management in hemodialysis (HD) patients treated in center. An Artificial Neural Network (ANN) algorithm for predicting hemoglobin concentrations three months into the future was developed and evaluated in a retrospective study on a sample population of 1558 HD patients treated with intravenous (IV) darbepoetin alfa, and IV iron (sucrose or gluconate). Model inputs were the last 90 days of patients' medical history and the subsequent 90 days of darbepoetin/iron prescription. Our model was able to predict individual variation of hemoglobin concentration 3 months in the future with a Mean Absolute Error (MAE) of 0.75 g/dL. Error analysis showed a narrow Gaussian distribution centered in 0 g/dL; a root cause analysis identified intercurrent and/or unpredictable events associated with hospitalization, blood transfusion, and laboratory error or misreported hemoglobin values as the main reasons for large discrepancy between predicted versus observed hemoglobin values. Our ANN predictive model offers a simple and reliable tool applicable in daily clinical practice for predicting the long-term response to ESA/iron therapy of HD patients.

  16. Long-term fluctuations of Pelagia noctiluca (Cnidaria, Scyphomedusa) in the western Mediterranean Sea. Prediction by climatic variables

    NASA Astrophysics Data System (ADS)

    Goy, Jacquelinn; Morand, Pierre; Etienne, Michéle

    1989-02-01

    The archives of the Station Zoologique at Villefranche-sur-Mer contain records of "years with Pelagia noctiluca" and 'years without Pelagia". These records, plus additional data, indicate that over the past 200 years (1785-1985) outburst of Pelagia have occured about every 12 years. Using a forecasting model, climatic variables, notably temperature, rainfall and atmospheric pressure, appear to predict "years with Pelagia".

  17. Shrinking the Psoriasis Assessment Gap: Early Gene-Expression Profiling Accurately Predicts Response to Long-Term Treatment.

    PubMed

    Correa da Rosa, Joel; Kim, Jaehwan; Tian, Suyan; Tomalin, Lewis E; Krueger, James G; Suárez-Fariñas, Mayte

    2017-02-01

    There is an "assessment gap" between the moment a patient's response to treatment is biologically determined and when a response can actually be determined clinically. Patients' biochemical profiles are a major determinant of clinical outcome for a given treatment. It is therefore feasible that molecular-level patient information could be used to decrease the assessment gap. Thanks to clinically accessible biopsy samples, high-quality molecular data for psoriasis patients are widely available. Psoriasis is therefore an excellent disease for testing the prospect of predicting treatment outcome from molecular data. Our study shows that gene-expression profiles of psoriasis skin lesions, taken in the first 4 weeks of treatment, can be used to accurately predict (>80% area under the receiver operating characteristic curve) the clinical endpoint at 12 weeks. This could decrease the psoriasis assessment gap by 2 months. We present two distinct prediction modes: a universal predictor, aimed at forecasting the efficacy of untested drugs, and specific predictors aimed at forecasting clinical response to treatment with four specific drugs: etanercept, ustekinumab, adalimumab, and methotrexate. We also develop two forms of prediction: one from detailed, platform-specific data and one from platform-independent, pathway-based data. We show that key biomarkers are associated with responses to drugs and doses and thus provide insight into the biology of pathogenesis reversion.

  18. Both Nearest Neighbours and Long-term Affiliates Predict Individual Locations During Collective Movement in Wild Baboons

    PubMed Central

    Farine, Damien R.; Strandburg-Peshkin, Ariana; Berger-Wolf, Tanya; Ziebart, Brian; Brugere, Ivan; Li, Jia; Crofoot, Margaret C.

    2016-01-01

    In many animal societies, groups of individuals form stable social units that are shaped by well-delineated dominance hierarchies and a range of affiliative relationships. How do socially complex groups maintain cohesion and achieve collective movement? Using high-resolution GPS tracking of members of a wild baboon troop, we test whether collective movement in stable social groups is governed by interactions among local neighbours (commonly found in groups with largely anonymous memberships), social affiliates, and/or by individuals paying attention to global group structure. We construct candidate movement prediction models and evaluate their ability to predict the future trajectory of focal individuals. We find that baboon movements are best predicted by 4 to 6 neighbours. While these are generally individuals’ nearest neighbours, we find that baboons have distinct preferences for particular neighbours, and that these social affiliates best predict individual location at longer time scales (>10 minutes). Our results support existing theoretical and empirical studies highlighting the importance of local rules in driving collective outcomes, such as collective departures, in primates. We extend previous studies by elucidating the rules that maintain cohesion in baboons ‘on the move’, as well as the different temporal scales of social interactions that are at play. PMID:27292778

  19. Comparison of the predictions of one- and two-compartment microcomputer programs for long-term tobramycin therapy.

    PubMed

    Hatton, R C; Massey, K L; Russell, W L

    1984-01-01

    A retrospective study of patients receiving tobramycin compared the accuracy of predictions of actual trough serum concentrations using two commercially available microcomputer software programs. Twelve patients met the study criteria of intravenous tobramycin treatment for more than 10 days with serum concentration monitoring within the first 5 days and after 10 days of therapy. No patients received dialysis. Twenty-five serum concentrations were compared. Predictions within 0.2 microgram/ml were considered clinically "exact." No significant differences were found by chi-square analysis for any of the four possible choices (p less than 0.3). One of the programs, distributed by Dista Pharmaceuticals, offers a one-compartment model, a two-compartment model, and a two-compartment prenephrotoxic option. SIMKIN, a program marketed by Medical Engineering, Inc., uses a two-compartment model. Overall, the predictions errors were small, but occasionally were clinically significant. Further evaluation of microcomputer programs for therapeutic drug monitoring is necessary to document their impact on predicting drug efficacy and toxicity.

  20. Genomic Models of Short-Term Exposure Accurately Predict Long-Term Chemical Carcinogenicity and Identify Putative Mechanisms of Action

    PubMed Central

    Gusenleitner, Daniel; Auerbach, Scott S.; Melia, Tisha; Gómez, Harold F.; Sherr, David H.; Monti, Stefano

    2014-01-01

    Background Despite an overall decrease in incidence of and mortality from cancer, about 40% of Americans will be diagnosed with the disease in their lifetime, and around 20% will die of it. Current approaches to test carcinogenic chemicals adopt the 2-year rodent bioassay, which is costly and time-consuming. As a result, fewer than 2% of the chemicals on the market have actually been tested. However, evidence accumulated to date suggests that gene expression profiles from model organisms exposed to chemical compounds reflect underlying mechanisms of action, and that these toxicogenomic models could be used in the prediction of chemical carcinogenicity. Results In this study, we used a rat-based microarray dataset from the NTP DrugMatrix Database to test the ability of toxicogenomics to model carcinogenicity. We analyzed 1,221 gene-expression profiles obtained from rats treated with 127 well-characterized compounds, including genotoxic and non-genotoxic carcinogens. We built a classifier that predicts a chemical's carcinogenic potential with an AUC of 0.78, and validated it on an independent dataset from the Japanese Toxicogenomics Project consisting of 2,065 profiles from 72 compounds. Finally, we identified differentially expressed genes associated with chemical carcinogenesis, and developed novel data-driven approaches for the molecular characterization of the response to chemical stressors. Conclusion Here, we validate a toxicogenomic approach to predict carcinogenicity and provide strong evidence that, with a larger set of compounds, we should be able to improve the sensitivity and specificity of the predictions. We found that the prediction of carcinogenicity is tissue-dependent and that the results also confirm and expand upon previous studies implicating DNA damage, the peroxisome proliferator-activated receptor, the aryl hydrocarbon receptor, and regenerative pathology in the response to carcinogen exposure. PMID:25058030

  1. Prediction of Long-Term Benefits of Inhaled Steroids by Phenotypic Markers in Moderate-to-Severe COPD: A Randomized Controlled Trial

    PubMed Central

    Snoeck-Stroband, Jiska B.; Lapperre, Therese S.; Sterk, Peter J.; Hiemstra, Pieter S.; Thiadens, Henk A.; Boezen, H. Marike; ten Hacken, Nick H. T.; Kerstjens, Huib A. M.; Postma, Dirkje S.; Timens, Wim; Sont, Jacob K.

    2015-01-01

    Background The decline in lung function can be reduced by long-term inhaled corticosteroid (ICS) treatment in subsets of patients with chronic obstructive pulmonary disease (COPD). We aimed to identify which clinical, physiological and non-invasive inflammatory characteristics predict the benefits of ICS on lung function decline in COPD. Methods Analysis was performed in 50 steroid-naive compliant patients with moderate to severe COPD (postbronchodilator forced expiratory volume in one second (FEV1), 30–80% of predicted, compatible with GOLD stages II-III), age 45–75 years, >10 packyears smoking and without asthma. Patients were treated with fluticasone propionate (500 μg bid) or placebo for 2.5 years. Postbronchodilator FEV1, dyspnea and health status were measured every 3 months; lung volumes, airway hyperresponsiveness (PC20), and induced sputum at 0, 6 and 30 months. A linear mixed effect model was used for analysis of this hypothesis generating study. Results Significant predictors of attenuated FEV1-decline by fluticasone treatment compared to placebo were: fewer packyears smoking, preserved diffusion capacity, limited hyperinflation and lower inflammatory cell counts in induced sputum (p<0.04). Conclusions Long-term benefits of ICS on lung function decline in patients with moderate-to-severe COPD are most pronounced in patients with fewer packyears, and less severe emphysema and inflammation. These data generate novel hypotheses on phenotype-driven therapy in COPD. Trial Registration ClinicalTrials.gov NCT00158847 PMID:26659582

  2. Using the Autism Detection in Early Childhood (ADEC) and Childhood Autism Rating Scales (CARS) to predict long term outcomes in children with autism spectrum disorders.

    PubMed

    Nah, Yong-Hwee; Young, Robyn L; Brewer, Neil

    2014-09-01

    This study evaluated the predictive validity of the Autism Detection in Early Childhood (ADEC; Young, Autism detection in early childhood: ADEC. Australian Council of Educational Research, Camberwell, VIC 2007) and a well-established screening tool, the Childhood Autism Rating Scale (CARS; Schopler et al. The childhood autism rating scale (CARS). Western Psychological Services, Los Angeles 1988), for long term outcomes of children with ASD engaged in an early intervention program. Participants were 55 children (44 male, 11 female) aged 19–42 months (M = 33.5, SD = 5.6) at initial assessment who were followed up 2 and 6 years after their initial assessment. The ADEC and the CARS performed similarly when predicting long term outcomes such as clinical diagnostic outcome and overall adaptive functioning level. However, only the ADEC score was significantly correlated with ASD symptom severity at the 6-year follow up. Although these findings need to be replicated with additional and larger samples, this study extends our understanding of the psychometric properties of both the ADEC and the CARS.

  3. Short term response is predictive of long term response to acetylcholinesterase inhibitors in Alzheimer’s disease: A starting point to explore Bayesian approximation in clinical practice

    PubMed Central

    Rota, Eugenia; Ferrero, Patrizia; Ursone, Rita; Migliaretti, Giuseppe

    2007-01-01

    This study was aimed at identifying, in 203 patients with Alzheimer's disease followed during long-term treatment with Acetylcholinesterase inhibitors (ChEIs), the predictive factors of the clinical response among cognition (MMSE), functioning (BADL and IADL) measures and age and gender at the baseline (T0). The ANCOVA test showed a significant association between MMSE scores at time T0 and T3, and the variation T9 to T0, T15 to T0 and T21 to T0 of the MMSE scores, using also gender, age and drug as covariates. The significance was higher for the patients affected by mild dementia. Regarding functional activities, a significant relationship was detected, by the ANCOVA test, only between the scores at T3 and the variation T15 to T0 for BADL, and the variation T9 to T0, T15 to T0 for IADL, respectively. Our results confirm, in a real world setting, that ChEIs provide long-term cognitive benefit, which is correlated to, and predictable by, the short-term response (within the third month) as well as the cognitive status (evaluated by means of the MMSE) at the beginning of the treatment. These factors should be the basis of any cost/effectiveness algorithm in health economic decision models. PMID:18188418

  4. Predicting the effects of human developments on individual dolphins to understand potential long-term population consequences.

    PubMed

    Pirotta, Enrico; Harwood, John; Thompson, Paul M; New, Leslie; Cheney, Barbara; Arso, Monica; Hammond, Philip S; Donovan, Carl; Lusseau, David

    2015-11-07

    Human activities that impact wildlife do not necessarily remove individuals from populations. They may also change individual behaviour in ways that have sublethal effects. This has driven interest in developing analytical tools that predict the population consequences of short-term behavioural responses. In this study, we incorporate empirical information on the ecology of a population of bottlenose dolphins into an individual-based model that predicts how individuals' behavioural dynamics arise from their underlying motivational states, as well as their interaction with boat traffic and dredging activities. We simulate the potential effects of proposed coastal developments on this population and predict that the operational phase may affect animals' motivational states. For such results to be relevant for management, the effects on individuals' vital rates also need to be quantified. We investigate whether the relationship between an individual's exposure and the survival of its calves can be directly estimated using a Bayesian multi-stage model for calf survival. The results suggest that any effect on calf survival is probably small and that a significant relationship could only be detected in large, closely studied populations. Our work can be used to guide management decisions, accelerate the consenting process for coastal and offshore developments and design targeted monitoring.

  5. Predicting the effects of human developments on individual dolphins to understand potential long-term population consequences

    PubMed Central

    Pirotta, Enrico; Harwood, John; Thompson, Paul M.; New, Leslie; Cheney, Barbara; Arso, Monica; Hammond, Philip S.; Donovan, Carl; Lusseau, David

    2015-01-01

    Human activities that impact wildlife do not necessarily remove individuals from populations. They may also change individual behaviour in ways that have sublethal effects. This has driven interest in developing analytical tools that predict the population consequences of short-term behavioural responses. In this study, we incorporate empirical information on the ecology of a population of bottlenose dolphins into an individual-based model that predicts how individuals' behavioural dynamics arise from their underlying motivational states, as well as their interaction with boat traffic and dredging activities. We simulate the potential effects of proposed coastal developments on this population and predict that the operational phase may affect animals' motivational states. For such results to be relevant for management, the effects on individuals' vital rates also need to be quantified. We investigate whether the relationship between an individual's exposure and the survival of its calves can be directly estimated using a Bayesian multi-stage model for calf survival. The results suggest that any effect on calf survival is probably small and that a significant relationship could only be detected in large, closely studied populations. Our work can be used to guide management decisions, accelerate the consenting process for coastal and offshore developments and design targeted monitoring. PMID:26511044

  6. Long-term biomonitoring of breast cancer patients under adjuvant chemotherapy: the comet assay as a possible predictive factor.

    PubMed

    Uriol, E; Sierra, M; Comendador, M A; Fra, J; Martínez-Camblor, P; Lacave, A J; Sierra, L M

    2013-01-01

    Most chemotherapy treatments induce DNA damage in the exposed patients. Using the comet assay and peripheral blood mononuclear cells (PBMC), we have quantified this induced DNA damage and studied its relationship with GSTM1 and GSTT1 polymorphisms, and clinical parameters. For this purpose, 29 Caucasian women, breast cancer patients under CMF or CEF adjuvant chemotherapy were included in the study. The clinical parameters considered were (i) therapies side effects, like haematological and biochemical toxicities, (ii) prognostic and predictive factors, like hormonal receptor expression, tumour differentiation degree, sickness stage, and nodal status, and (iii) the effectiveness of the chemotherapy measured as five years relapse probability. The results were also related to the confounding factor age. Comet assay results indicate that 13 patients were characterised by absence of induced DNA strand breaks, and 16 patients presented induced DNA strand breaks along the treatment. Relationships between comet variables and clinical parameters, found with principal component analysis, correlations, one-way ANOVA and multivariate logistic regression analyses revealed that: (1) baseline levels of DNA damage are related to GSTM1 genotype and to hormonal receptor expression; (2) GSTM1 genotype also influences comet results after chemotherapy, as it does the AST level; (3) the tail moment values of the cycle 6.1 and the sickness stage might predict cancer relapse at five years: for the Stage, OR = 13.8 (IIB versus I+IIA), 95% CI 0.80-238.97, and for 6.1 cycle TM, OR = 1.3, 95%, CI 0.97-1.79, with a potential model (10* Stage (I-IIA = 0, IIB = 1) + 6.1 cycle), that has a good predictive capacity, with an area under ROC curve of 0.872 (CI 0.62-1.00). To our knowledge, this is the first time such a predictive value is found for the comet assay. Nevertheless, before the comet assay could be used as a tool for oncologists, this relationship should be confirmed in more patients, and

  7. On the importance of coupled THM processes to predict the long-term response of a generic salt repository for high-level nuclear waste

    NASA Astrophysics Data System (ADS)

    Blanco Martin, L.; Rutqvist, J.; Birkholzer, J. T.

    2013-12-01

    Salt is a potential medium for the underground disposal of nuclear waste because it has several assets, in particular its ability to creep and heal fractures generated by excavation and its water and gas tightness in the undisturbed state. In this research, we focus on disposal of heat-generating nuclear waste (such as spent fuel) and we consider a generic salt repository with in-drift emplacement of waste packages and subsequent backfill of the drifts with run-of-mine crushed salt. As the natural salt creeps, the crushed salt backfill gets progressively compacted and an engineered barrier system is subsequently created. In order to evaluate the integrity of the natural and engineered barriers over the long-term, it is important to consider the coupled effects of the thermal, hydraulic and mechanical processes that take place. In particular, the results obtained so far show how the porosity reduction of the crushed salt affects the saturation and pore pressure evolution throughout the repository, both in time and space. Such compaction is induced by the stress and temperature regime within the natural salt. Also, transport properties of the host rock are modified not only by thermo-mechanically and hydraulically-induced damaged processes, but also by healing/sealing of existing fractures. In addition, the THM properties of the backfill evolve towards those of the natural salt during the compaction process. All these changes are based on dedicated laboratory experiments and on theoretical considerations [1-3]. Different scenarios are modeled and compared to evaluate the relevance of different processes from the perspective of effective nuclear waste repositories. The sensitivity of the results to some parameters, such as capillarity, is also addressed. The simulations are conducted using an updated version of the TOUGH2-FLAC3D simulator, which is based on a sequential explicit method to couple flow and geomechanics [4]. A new capability for large strains and creep

  8. Early post-transplant urinary IP-10 expression after kidney transplantation is predictive of short- and long-term graft function.

    PubMed

    Matz, M; Beyer, J; Wunsch, D; Mashreghi, M-F; Seiler, M; Pratschke, J; Babel, N; Volk, H-D; Reinke, P; Kotsch, K

    2006-05-01

    The early identification of renal transplant recipients at enhanced risk of developing acute and subclinical rejection would allow individualized adjustment of immunosuppression before functional graft injury occurs and would exclude these patients from drug-weaning studies. Protein and reverse transcriptase-polymerase chain reaction-based analyses of candidate markers in urine open the opportunity to closely monitor kidney-transplanted patients non-invasively. The chemokine interferon-inducible protein 10 (IP-10; CXCL10) might be an interesting candidate to uncover ongoing immune processes within the graft. Urine samples from kidney-transplanted recipients were retrospectively analyzed for IP-10 mRNA and protein expression. IP-10 levels were correlated with the incidence of acute rejection episodes proven by histology and long-term graft function assessed by the glomerular filtration rate 6 months post transplantation. IP-10 expression in urine identified patients with ongoing acute rejection episodes several days before a biopsy was indicated by rising serum creatinine levels. Most importantly, elevated levels of urinary IP-10 protein within the first four postoperative weeks were predictive of graft function at 6 months even in the absence of acute rejection. These data reveal a correlation between elevated IP-10 expression in urine at early time points post-transplantation and intragraft immune activation that leads to acute rejection and compromised long-term graft function.

  9. Satellite-driven predictions of animal migrations in response to short and long-term environmental change

    NASA Astrophysics Data System (ADS)

    Beck, P. S.; Bohrer, G.; Wethington, S.; Bartlam-Brooks, H. L.; Powers, D. R.; Goetz, S. J.; Graham, C. H.

    2012-12-01

    Animal migrations have evolved in response to spatio-temporal heterogeneity in resources, habitats, predation, and competition. Their reliance on disjunct habitats makes migratory animals potentially more vulnerable to extreme climate events or phenological changes at other trophic levels. The advent of affordable satellite-based tracking technology has revolutionized the study of animal movement in the past two decades. Understanding internal and external drivers of migratory behavior, and how they interact, is critical for migration ecology to move beyond solely the measurement and description of organism-level movement and to predict how environmental change might affect migrations. To achieve this, it is necessary to not only measure animals' movement but also their reliance on prevailing external, i.e. environmental, conditions prior to, and during migration. An increasingly wide array of satellite and model-derived gridded data sets that map environmental conditions at regular temporal intervals are now readily accessible because of standardized processing and data formats, as well as a variety of online portals that provide host data archives and/or on-demand processing free-of-charge. While they are often of coarser spatial resolution, these data can overcome many limitations of in situ measurements with regard to spatial extent and temporal frequency. We demonstrate the use of global gridded environmental time-series in the study of animal migrations through case studies. First we show how inter-annual weather variation in wintering habitats affects migratory behavior of broad-tailed hummingbirds and investigate how it carries over to their reproductive success and survival in summer habitats. To do so, we use vegetation indices as proxies of resource availability, and the NCEP Climate Forecast System Reanalysis (CFSR) to map known physiological constraints on the birds. Secondly, we investigated the effects of long as well as short-term variations in

  10. Future global and regional climate change: From near-term prediction to long-term projections (Invited)

    NASA Astrophysics Data System (ADS)

    Knutti, R.; Collins, M.; Power, S.; Kirtman, B. P.; Christensen, J. H.; Krishna Kumar, K.

    2013-12-01

    The IPCC AR5 assessed results from a hierarchy of different climate models on how climate might change in the future from decades to millennia. The projections are based on a series of new climate models and for new scenarios. They are very consistent with projections in AR4 and confirm widespread changes in the atmosphere, ocean, sea ice and land under emission scenarios without mitigation. In the late 21st century and beyond, the warming is dominated by the total emissions of CO2, and many changes will persist for centuries even if emissions were stopped. Stabilization of global temperature at 2°C above the preindustrial value for example, requires strong emission reductions over the 21st century. In the near term and locally however, interannual and decadal climate variability remains a large and mostly irreducible component of the uncertainty in projections. Improving the quality of information on regional climate change and improving the ability of the scientific community to perform near-term climate predictions are key challenges for the future. The development of a consensus in the climate science community on (i) the major directions for future model development and (ii) the scope of future coordinated model experiments will help serve the needs of both future IPCC assessments and the wider research community.

  11. Long-term landscape trajectory - Can we make predictions about landscape form and function for post-mining landforms?

    NASA Astrophysics Data System (ADS)

    Hancock, G. R.; Lowry, J. B. C.; Coulthard, T. J.

    2016-08-01

    A significant issue for the application of numerical Landscape Evolution Models (LEMs) is their calibration/parameterisation and validation. LEMs are now at the stage of development where if calibrated, they can provide meaningful and useful results. However, before use, each LEM requires a set of data and parameter values for it to run reliably and most importantly produce results with some measure of precision and accuracy. This calibration/validation process is largely carried out using parameter values determined from present day, or recent surface conditions which are themselves product of much longer-term geology-soil-climate-vegetation interactions. Here we examine the reliability of an LEM to predict catchment form over geological time (500,000 years) for a potential rehabilitated mine landform using defensible parameters derived from field plots. The findings demonstrate that there is no equifinality in landscape form with different parameter sets producing geomorphically and hydrologically unique landscapes throughout their entire evolution. This shows that parameterisation does matter over geological time scales. However, for shorter time scales (< 10,000 years) the geomorphic differences in hillslope form are minimal as described by the hypsometric curve, area-slope and cumulative area distribution, yet there are large differences in sediment output. Therefore, obtaining reliable and defensible parameters for input to LEMs is essential.

  12. Long-term prediction of emergency department revenue and visitor volume using autoregressive integrated moving average model.

    PubMed

    Chen, Chieh-Fan; Ho, Wen-Hsien; Chou, Huei-Yin; Yang, Shu-Mei; Chen, I-Te; Shi, Hon-Yi

    2011-01-01

    This study analyzed meteorological, clinical and economic factors in terms of their effects on monthly ED revenue and visitor volume. Monthly data from January 1, 2005 to September 30, 2009 were analyzed. Spearman correlation and cross-correlation analyses were performed to identify the correlation between each independent variable, ED revenue, and visitor volume. Autoregressive integrated moving average (ARIMA) model was used to quantify the relationship between each independent variable, ED revenue, and visitor volume. The accuracies were evaluated by comparing model forecasts to actual values with mean absolute percentage of error. Sensitivity of prediction errors to model training time was also evaluated. The ARIMA models indicated that mean maximum temperature, relative humidity, rainfall, non-trauma, and trauma visits may correlate positively with ED revenue, but mean minimum temperature may correlate negatively with ED revenue. Moreover, mean minimum temperature and stock market index fluctuation may correlate positively with trauma visitor volume. Mean maximum temperature, relative humidity and stock market index fluctuation may correlate positively with non-trauma visitor volume. Mean maximum temperature and relative humidity may correlate positively with pediatric visitor volume, but mean minimum temperature may correlate negatively with pediatric visitor volume. The model also performed well in forecasting revenue and visitor volume.

  13. Coronary atherosclerosis burden, but not transient troponin elevation, predicts long-term outcome in recreational marathon runners.

    PubMed

    Möhlenkamp, Stefan; Leineweber, Kirsten; Lehmann, Nils; Braun, Siegmund; Roggenbuck, Ulla; Perrey, Mareike; Broecker-Preuss, Martina; Budde, Thomas; Halle, Martin; Mann, Klaus; Jöckel, Karl-Heinz; Erbel, Raimund; Heusch, Gerd

    2014-01-01

    We determined the prognostic value of transient increases in high-sensitive serum troponin I (hsTnI) during a marathon and its association with traditional cardiovascular risk factors and imaging-based risk markers for incident coronary events and all-cause mortality in recreational marathon runners. Baseline data of 108 marathon runners, 864 age-matched controls and 216 age- and risk factor-matched controls from the general population were recorded and their coronary event rates and all-cause mortality after 6 ± 1 years determined. hsTnI was measured in 74 marathon finishers before and after the race. Other potential predictors for coronary events, i.e., Framingham Risk Score (FRS), coronary artery calcium (CAC) and presence of myocardial fibrosis as measured by magnetic resonance imaging-based late gadolinium enhancement (LGE), were also assessed. An increase beyond the 99 % hsTnI-threshold, i.e., 0.04 μg/L, was observed in 36.5 % of runners. FRS, CAC, or prevalent LGE did not predict hsTnI values above or increases in hsTnI beyond the median after the race, nor did they predict future events. However, runners with versus without LGE had higher hsTnI values after the race (median (Q1/Q3), 0.08 μg/L (0.04/0.09) versus 0.03 μg/L (0.02/0.06), p = 0.039), and higher increases in hsTnI values during the race (median (Q1/Q3), 0.05 μg/L (0.03/0.08) versus 0.02 μg/L (0.01/0.05), p = 0.0496). Runners had a similar cumulative event rate as age-matched or age- and risk factor-matched controls, i.e., 6.5 versus 5.0 % or 4.6 %, respectively. Event rates in runners with CAC scores <100, 100-399, and ≥400 were 1.5, 12.0, and 21.4 % (p = 0.002 for trend) and not different from either control group. Runners with coronary events had a higher prevalence of LGE than runners without events (57 versus 8 %, p = 0.003). All-cause mortality was similar in marathon runners (3/108, 2.8 %) and controls (26/864, 3.0 % or 5/216, 2.4 %, respectively). Recreational marathon runners with

  14. Simulating infectious disease risk based on climatic drivers: from numerical weather prediction to long term climate change scenario

    NASA Astrophysics Data System (ADS)

    Caminade, C.; Ndione, J. A.; Diallo, M.; MacLeod, D.; Faye, O.; Ba, Y.; Dia, I.; Medlock, J. M.; Leach, S.; McIntyre, K. M.; Baylis, M.; Morse, A. P.

    2012-04-01

    Climate variability is an important component in determining the incidence of a number of diseases with significant health and socioeconomic impacts. In particular, vector born diseases are the most likely to be affected by climate; directly via the development rates and survival of both the pathogen and the vector, and indirectly through changes in the surrounding environmental conditions. Disease risk models of various complexities using different streams of climate forecasts as inputs have been developed within the QWeCI EU and ENHanCE ERA-NET project frameworks. This work will present two application examples, one for Africa and one for Europe. First, we focus on Rift Valley fever over sub-Saharan Africa, a zoonosis that affects domestic animals and humans by causing an acute fever. We show that the Rift Valley fever outbreak that occurred in late 2010 in the northern Sahelian region of Mauritania might have been anticipated ten days in advance using the GFS numerical weather prediction system. Then, an ensemble of regional climate projections is employed to model the climatic suitability of the Asian tiger mosquito for the future over Europe. The Asian tiger mosquito is an invasive species originally from Asia which is able to transmit West Nile and Chikungunya Fever among others. This species has spread worldwide during the last decades, mainly through the shipments of goods from Asia. Different disease models are employed and inter-compared to achieve such a task. Results show that the climatic conditions over southern England, central Western Europe and the Balkans might become more suitable for the mosquito (including the proviso that the mosquito has already been introduced) to establish itself in the future.

  15. [Usefulness of the residual SYNTAX score to predict long term outcome in acute coronary syndrome patients underwent percutaneous coronary intervention].

    PubMed

    Song, Y; Xu, J J; Tang, X F; Ma, Y L; Yao, Y; He, C; Wang, H H; Liu, R; Xu, N; Jiang, P; Jiang, L; Zhao, X Y; Gao, Z; Gao, R L; Qiao, S B; Yang, Y J; Xu, B; Yuan, J Q

    2017-02-21

    Objective: To quantify the extent and complexity of residual coronary stenosis following PCI by the residual SYNTAX score, and to evaluate its impact on adverse ischemic outcomes in acute coronary syndrome(ACS) patients. Methods: From January 2013 to December 2013, a total of 1 414 consecutive moderate- and high-risk ACS patients who underwent any PCI with multi-vessel coronary artery disease were evaluated.Patients were stratified by rSS quartiles and their outcomes were compared. Results: The rSS was 4.8±6.7. 591 patients (41.8%) had rSS=0(CR), 233 patients (16.5%) had rSS>0 but ≤ 3, 296 patients (20.9%) had rSS>3 but ≤8 and 294 patients (20.8%) had rSS>8.Clinical risk factors were more frequent in patients with incomplete revascularization(IR) compared with complete revascularization(CR). The 2-year rates of all-caused death(1.2% vs 0.4%, 2.0%, 4.4%, P=0.003), cardiac death, revascularization and MACCE were significantly higher in high rSS group, compared to other groups.By multivariable analysis, rSS was a strong independent predictor of ischemic outcomes at 2-year, including all-cause mortality (HR=1.05, 95%CI 1.01-1.09, P=0.019), cardiac death, revascularization and MACCE. Conclusions: The rSS is a strong independent predictor of all-caused death, cardiac death, revascularization and MACCE and has moderated predictive ability for those ischemic outcomes.

  16. Using the Oxford classification of IgA nephropathy to predict long-term outcomes of Henoch-Schönlein purpura nephritis in adults.

    PubMed

    Kim, Chan Ho; Lim, Beom Jin; Bae, Yoon Sung; Kwon, Young Eun; Kim, Yung Ly; Nam, Ki Heon; Park, Kyoung Sook; An, Seong Yeong; Koo, Hyang Mo; Doh, Fa Mee; Lee, Mi Jung; Oh, Hyung Jung; Yoo, Tae-Hyun; Kang, Shin-Wook; Choi, Kyu Hun; Jeong, Hyun Joo; Han, Seung Hyeok

    2014-07-01

    Recently, there has been emerging concern that crescents, the main histologic feature of Henoch-Schönlein purpura nephritis, merely reflect active inflammation, and may not be useful in predicting long-term outcomes. We therefore conducted a single-center retrospective study to evaluate whether the new Oxford classification of immunoglobulin A nephropathy can be used to predict long-term outcome in patients with Henoch-Schönlein purpura nephritis. We included 61 biopsy-proven patients with Henoch-Schönlein purpura nephritis between January 1991 and August 2010. In addition to the International Study of Kidney Disease in Children classification, pathologic findings were also evaluated by the Oxford classification. Primary outcomes were defined as either the onset of estimated glomerular filtration rate <60 ml/min per 1.73 m(2) with ≥30% decrease in estimated glomerular filtration rate from baseline or end-stage renal disease. During a median follow-up of 49.3 months, 13 (21%) patients reached the primary end point. A Kaplan-Meier plot showed that renal event-free survival was significantly longer in patients with <50% crescents than in those with crescents in ≥50% of glomeruli (P=0.003). Among the components of the Oxford classification, patients with endocapillary hypercellularity (E1; P=0.016) and tubular atrophy/interstitial fibrosis (T1/T2; P=0.018) had lower renal survival rates than those with E0 and T0. In a multivariate Cox model adjusted for clinical and pathologic factors, E1 (hazard ratio=8.91; 95% confidence interval=1.47-53.88; P=0.017) and T1/T2 (hazard ratio=8.74; 95% confidence interval=1.40-54.38; P=0.020) were independently associated with reaching a primary outcome, whereas the extent of crescentic lesions was not. Our findings suggest that the Oxford classification can be used in predicting long-term outcomes of Henoch-Schönlein purpura nephritis.

  17. Clinical Significance of the Prognostic Nutritional Index for Predicting Short- and Long-Term Surgical Outcomes After Gastrectomy: A Retrospective Analysis of 7781 Gastric Cancer Patients.

    PubMed

    Lee, Jee Youn; Kim, Hyoung-Il; Kim, You-Na; Hong, Jung Hwa; Alshomimi, Saeed; An, Ji Yeong; Cheong, Jae-Ho; Hyung, Woo Jin; Noh, Sung Hoon; Kim, Choong-Bai

    2016-05-01

    To evaluate the predictive and prognostic significance of the prognostic nutritional index (PNI) in a large cohort of gastric cancer patients who underwent gastrectomy.Assessing a patient's immune and nutritional status, PNI has been reported as a predictive marker for surgical outcomes in various types of cancer.We retrospectively reviewed data from a prospectively maintained database of 7781 gastric cancer patients who underwent gastrectomy from January 2001 to December 2010 at a single center. From this data, we analyzed clinicopathologic characteristics, PNI, and short- and long-term surgical outcomes for each patient. We used the PNI value for the 10th percentile (46.70) of the study cohort as a cut-off for dividing patients into low and high PNI groups.Regarding short-term outcomes, multivariate analysis showed a low PNI (odds ratio [OR] = 1.505, 95% CI = 1.212-1.869, P <0.001), old age, male sex, high body mass index, medical comorbidity, total gastrectomy, and combined resection to be independent predictors of postoperative complications. Among these, only low PNI (OR = 4.279, 95% CI = 1.760-10.404, P = 0.001) and medical comorbidity were independent predictors of postoperative mortality. For long-term outcomes, low PNI was a poor prognostic factor for overall survival, but not recurrence (overall survival: hazard ratio [HR] = 1.383, 95% CI = 1.221-1.568, P < 0.001; recurrence-free survival: HR = 1.142, 95% CI = 0.985-1.325, P = 0.078).PNI can be used to predict patients at increased risk of postoperative morbidity and mortality. Although PNI was an independent prognostic factor for overall survival, the index was not associated with cancer recurrence.

  18. Usefulness of Combining Galectin-3 and BIVA Assessments in Predicting Short- and Long-Term Events in Patients Admitted for Acute Heart Failure

    PubMed Central

    De Berardinis, Benedetta; Magrini, Laura; Zampini, Giorgio; Zancla, Benedetta; Salerno, Gerardo; Cardelli, Patrizia; Di Stasio, Enrico; Gaggin, Hanna K.; Belcher, Arianna; Parry, Blair A.; Nagurney, John T.; Januzzi, James L.; Di Somma, Salvatore

    2014-01-01

    Introduction. Acute heart failure (AHF) is associated with a higher risk for the occurrence of rehospitalization and death. Galectin-3 (GAL3) is elevated in AHF patients and is an indicator in predicting short-term mortality. The total body water using bioimpedance vector analysis (BIVA) is able to identify mortality within AHF patients. The aim of this study was to evaluate the short- and long-term predictive value of GAL3, BIVA, and the combination of both in AHF patients in Emergency Department (ED). Methods. 205 ED patients with AHF were evaluated by testing for B type natriuretic peptide (BNP) and GAL3. The primary endpoint was death and rehospitalization at 30, 60, 90, and 180 days and 12 and 18 months. AHF patients were evaluated at the moment of ED arrival with clinical judgment and GAL3 and BIVA measurement. Results. GAL3 level was significantly higher in patients >71 years old, and with eGFR < 30 cc/min. The area under the curve (AUC) of GAL3 + BIVA, GAL3 and BIVA for death and rehospitalization both when considered in total and when considered serially for the follow-up period showed that the combination has a better prognostic value. Kaplan-Meier survival curve for GAL3 values >17.8 ng/mL shows significant survival difference. At multivariate Cox regression analysis GAL3 is an independent variable to predict death + rehospitalization with a value of 32.24 ng/mL at 30 days (P < 0.005). Conclusion. In patients admitted for AHF an early assessment of GAL3 and BIVA seems to be useful in identifying patients at high risk for death and rehospitalization at short and long term. Combining the biomarker and the device could be of great utility since they monitor the severity of two pathophysiological different mechanisms: heart fibrosis and fluid overload. PMID:25101304

  19. Ductility normalized-strainrange partitioning life relations for creep-fatigue life predictions

    NASA Technical Reports Server (NTRS)

    Halford, G. R.; Saltsman, J. F.; Hirschberg, M. H.

    1977-01-01

    Procedures based on Strainrange Partitioning (SRP) are presented for estimating the effects of environment and other influences on the high temperature, low cycle, creep fatigue resistance of alloys. It is proposed that the plastic and creep, ductilities determined from conventional tensile and creep rupture tests conducted in the environment of interest be used in a set of ductility normalized equations for making a first order approximation of the four SRP inelastic strainrange life relations. Different levels of sophistication in the application of the procedures are presented by means of illustrative examples with several high temperature alloys. Predictions of cyclic lives generally agree with observed lives within factors of three.

  20. Middle and long-term prediction of UT1-UTC based on combination of Gray Model and Autoregressive Integrated Moving Average

    NASA Astrophysics Data System (ADS)

    Jia, Song; Xu, Tian-he; Sun, Zhang-zhen; Li, Jia-jing

    2017-02-01

    UT1-UTC is an important part of the Earth Orientation Parameters (EOP). The high-precision predictions of UT1-UTC play a key role in practical applications of deep space exploration, spacecraft tracking and satellite navigation and positioning. In this paper, a new prediction method with combination of Gray Model (GM(1, 1)) and Autoregressive Integrated Moving Average (ARIMA) is developed. The main idea is as following. Firstly, the UT1-UTC data are preprocessed by removing the leap second and Earth's zonal harmonic tidal to get UT1R-TAI data. Periodic terms are estimated and removed by the least square to get UT2R-TAI. Then the linear terms of UT2R-TAI data are modeled by the GM(1, 1), and the residual terms are modeled by the ARIMA. Finally, the UT2R-TAI prediction can be performed based on the combined model of GM(1, 1) and ARIMA, and the UT1-UTC predictions are obtained by adding the corresponding periodic terms, leap second correction and the Earth's zonal harmonic tidal correction. The results show that the proposed model can be used to predict UT1-UTC effectively with higher middle and long-term (from 32 to 360 days) accuracy than those of LS + AR, LS + MAR and WLS + MAR.

  1. Short- and long-term recidivism prediction of the PCL-R and the effects of age: a 24-year follow-up.

    PubMed

    Olver, Mark E; Wong, Stephen C P

    2015-01-01

    We prospectively examined the short- and long-term prediction of several recidivism outcomes as a function of psychopathy and age in a sample of 273 Canadian federal inmates with an average 24 years post-release follow-up. Offenders were rated using the original 22-item Hare Psychopathy Checklist (PCL: Hare, 1980) based on extensive archival file information, and the ratings were used to compute the Psychopathy Checklist-Revised (Hare, 2003) and the 4 facet scores. PCL-R total scores and the Lifestyle and Antisocial facets, but not the Interpersonal and Affective facets, showed mostly small and some moderate predictive efficacy for general and nonviolent recidivism over 3-, 5-, 10-, and 20-year fixed follow-ups, and predicted violence recidivism at shorter follow-ups. Age at release was negatively correlated with all recidivism outcomes and follow-up periods for both high and low PCL-R rated offenders, and uniquely predicted all recidivism outcomes after controlling for the PCL-R using Cox regression survival analysis. Increased age was consistently linked to recidivism reduction even for psychopathic offenders. The results showed that both PCL-R scores and age contributed to the prediction of recidivism; however, the PCL-R facets made differential contributions that varied with the type of offense (violent vs. nonviolent) and follow-up time (shorter vs. longer). The results have implications for both risk assessment using the PCL-R and potentially for risk reduction interventions.

  2. The PER (Preoperative Esophagectomy Risk) Score: A Simple Risk Score to Predict Short-Term and Long-Term Outcome in Patients with Surgically Treated Esophageal Cancer

    PubMed Central

    Reeh, Matthias; Metze, Johannes; Uzunoglu, Faik G.; Nentwich, Michael; Ghadban, Tarik; Wellner, Ullrich; Bockhorn, Maximilian; Kluge, Stefan; Izbicki, Jakob R.; Vashist, Yogesh K.

    2016-01-01

    Abstract Esophageal resection in patients with esophageal cancer (EC) is still associated with high mortality and morbidity rates. We aimed to develop a simple preoperative risk score for the prediction of short-term and long-term outcomes for patients with EC treated by esophageal resection. In total, 498 patients suffering from esophageal carcinoma, who underwent esophageal resection, were included in this retrospective cohort study. Three preoperative esophagectomy risk (PER) groups were defined based on preoperative functional evaluation of different organ systems by validated tools (revised cardiac risk index, model for end-stage liver disease score, and pulmonary function test). Clinicopathological parameters, morbidity, and mortality as well as disease-free survival (DFS) and overall survival (OS) were correlated to the PER score. The PER score significantly predicted the short-term outcome of patients with EC who underwent esophageal resection. PER 2 and PER 3 patients had at least double the risk of morbidity and mortality compared to PER 1 patients. Furthermore, a higher PER score was associated with shorter DFS (P < 0.001) and OS (P < 0.001). The PER score was identified as an independent predictor of tumor recurrence (hazard ratio [HR] 2.1; P < 0.001) and OS (HR 2.2; P < 0.001). The PER score allows preoperative objective allocation of patients with EC into different risk categories for morbidity, mortality, and long-term outcomes. Thus, multicenter studies are needed for independent validation of the PER score. PMID:26886613

  3. Creep life prediction based on stochastic model of microstructurally short crack growth

    NASA Technical Reports Server (NTRS)

    Kitamura, Takayuki; Ohtani, Ryuichi

    1988-01-01

    A nondimensional model of microstructurally short crack growth in creep is developed based on a detailed observation of the creep fracture process of 304 stainless steel. In order to deal with the scatter of small crack growth rate data caused by microstructural inhomogeneity, a random variable technique is used in the model. A cumulative probability of the crack length at an arbitary time, G(bar a, bar t), and that of the time when a crack reaches an arbitary length, F(bar t, bar a), are obtained numerically by means of a Monte Carlo method. G(bar a, bar t), and F(bar t, bar a) are the probabilities for a single crack. However, multiple cracks generally initiate on the surface of a smooth specimen from the early stage of creep life to the final stage. TAking into account the multiple crack initiations, the actual crack length distribution observed on the surface of a specimen is predicted by the combination of probabilities for a single crack. The prediction shows a fairly good agreement with the experimental result for creep of 304 stainless steel at 923 K. The probability of creep life is obtained from an assumption that creep fracture takes place when the longest crack reaches a critical length. The observed and predicted scatter of the life is fairly small for the specimens tested.

  4. Creep life prediction based on stochastic model of microstructurally short crack growth

    NASA Technical Reports Server (NTRS)

    Kitamura, Takayuki; Ohtani, Ryuichi

    1989-01-01

    A nondimensional model of microstructurally short crack growth in creep is developed based on a detailed observation of the creep fracture process of 304 stainless steel. In order to deal with the scatter of small crack growth rate data caused by microstructural inhomogeneity, a random variable technique is used in the model. A cumulative probability of the crack length at an arbitrary time, G(bar a, bar t), and that of the time when a crack reaches an arbitrary length, F(bar t, bar a), are obtained numerically by means of a Monte Carlo method. G(bar a, bar t), and F(bar t, bar a) are the probabilities for a single crack. However, multiple cracks generally initiate on the surface of a smooth specimen from the early stage of creep life to the final stage. Taking into account the multiple crack initiations, the actual crack length distribution observed on the surface of a specimen is predicted by the combination of probabilities for a single crack. The prediction shows a fairly good agreement with the experimental result for creep of 304 stainless steel at 923 K. The probability of creep life is obtained from an assumption that creep fracture takes place when the longest crack reaches a critical length. The observed and predicted scatter of the life is fairly small for the specimens tested.

  5. Predicting successful long-term weight loss from short-term weight-loss outcomes: new insights from a dynamic energy balance model (the POUNDS Lost study)123

    PubMed Central

    Ivanescu, Andrada E; Martin, Corby K; Heymsfield, Steven B; Marshall, Kaitlyn; Bodrato, Victoria E; Williamson, Donald A; Anton, Stephen D; Sacks, Frank M; Ryan, Donna; Bray, George A

    2015-01-01

    Background: Currently, early weight-loss predictions of long-term weight-loss success rely on fixed percent-weight-loss thresholds. Objective: The objective was to develop thresholds during the first 3 mo of intervention that include the influence of age, sex, baseline weight, percent weight loss, and deviations from expected weight to predict whether a participant is likely to lose 5% or more body weight by year 1. Design: Data consisting of month 1, 2, 3, and 12 treatment weights were obtained from the 2-y Preventing Obesity Using Novel Dietary Strategies (POUNDS Lost) intervention. Logistic regression models that included covariates of age, height, sex, baseline weight, target energy intake, percent weight loss, and deviation of actual weight from expected were developed for months 1, 2, and 3 that predicted the probability of losing <5% of body weight in 1 y. Receiver operating characteristic (ROC) curves, area under the curve (AUC), and thresholds were calculated for each model. The AUC statistic quantified the ROC curve’s capacity to classify participants likely to lose <5% of their body weight at the end of 1 y. The models yielding the highest AUC were retained as optimal. For comparison with current practice, ROC curves relying solely on percent weight loss were also calculated. Results: Optimal models for months 1, 2, and 3 yielded ROC curves with AUCs of 0.68 (95% CI: 0.63, 0.74), 0.75 (95% CI: 0.71, 0.81), and 0.79 (95% CI: 0.74, 0.84), respectively. Percent weight loss alone was not better at identifying true positives than random chance (AUC ≤0.50). Conclusions: The newly derived models provide a personalized prediction of long-term success from early weight-loss variables. The predictions improve on existing fixed percent-weight-loss thresholds. Future research is needed to explore model application for informing treatment approaches during early intervention. The POUNDS Lost study was registered at clinicaltrials.gov as NCT00072995. PMID:25733628

  6. Plasma Apolipoprotein A-V Predicts Long-term Survival in Chronic Hepatitis B Patients with Acute-on-Chronic Liver Failure

    PubMed Central

    Chen, En-Qiang; Wang, Meng-Lan; Zhang, Dong-Mei; Shi, Ying; Wu, Do-Bo; Yan, Li-Bo; Du, Ling-Yao; Zhou, Ling-Yun; Tang, Hong

    2017-01-01

    Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is a life-threatening condition, and the lipid metabolism disorder is common in the development of this disease. This prospective observational study aimed to define the characteristics of plasma apolipoprotein A-V (apoA-V) in long-term outcome prediction of HBV-ACLF, and a total of 330 HBV-ACLF patients were included and followed for more than 12 months. In this cohort, the 4-week, 12-week, 24-week and 48-week cumulative mortality of HBV-ACLF was 18.2%(60/330), 50.9%(168/330), 59.7%(197/330) and 63.3%(209/330), respectively. As compared to survivors, the non-survivors had significantly lower concentrations of plasma apoA-V on admission. Plasma apoA-V concentrations were positively correlated with prothrombin time activity (PTA), and negatively correlated with interleukin-10, tumor necrosis factor-α, and iMELD scores. Though plasma apoA-V, PTA, total bilirubin(TBil) and blood urea nitrogen(BUN) were all independent factors to predict one-year outcomes of HBV-ACLF, plasma apoA-V had the highest prediction accuracy. And its optimal cutoff value for one-year survival prediction was 480.00 ng/mL, which had a positive predictive value of 84.68% and a negative predictive value of 92.23%. In summary, plasma apoA-V decreases significantly in non-survivors of HBV-ACLF, and it may be regarded as a new predictive marker for the prognosis of patients with HBV-ACLF. PMID:28358016

  7. Hypoxic Prostate/Muscle PO{sub 2} Ratio Predicts for Outcome in Patients With Localized Prostate Cancer: Long-Term Results

    SciTech Connect

    Turaka, Aruna; Buyyounouski, Mark K.; Hanlon, Alexandra L.; Horwitz, Eric M.; Greenberg, Richard E.; Movsas, Benjamin

    2012-03-01

    Purpose: To correlate tumor oxygenation status with long-term biochemical outcome after prostate brachytherapy. Methods and Materials: Custom-made Eppendorf PO{sub 2} microelectrodes were used to obtain PO{sub 2} measurements from the prostate (P), focused on positive biopsy locations, and normal muscle tissue (M), as a control. A total of 11,516 measurements were obtained in 57 men with localized prostate cancer immediately before prostate brachytherapy was given. The Eppendorf histograms provided the median PO{sub 2}, mean PO{sub 2}, and % <5 mm Hg or <10 mm Hg. Biochemical failure (BF) was defined using both the former American Society of Therapeutic Radiation Oncology (ASTRO) (three consecutive raises) and the current Phoenix (prostate-specific antigen nadir + 2 ng/mL) definitions. A Cox proportional hazards regression model evaluated the influence of hypoxia using the P/M mean PO{sub 2} ratio on BF. Results: With a median follow-up time of 8 years, 12 men had ASTRO BF and 8 had Phoenix BF. On multivariate analysis, P/M PO{sub 2} ratio <0.10 emerged as the only significant predictor of ASTRO BF (p = 0.043). Hormonal therapy (p = 0.015) and P/M PO{sub 2} ratio <0.10 (p = 0.046) emerged as the only independent predictors of the Phoenix BF. Kaplan-Meier freedom from BF for P/M ratio <0.10 vs. {>=}0.10 at 8 years for ASTRO BF was 46% vs. 78% (p = 0.03) and for the Phoenix BF was 66% vs. 83% (p = 0.02). Conclusions: Hypoxia in prostate cancer (low mean P/M PO{sub 2} ratio) significantly predicts for poor long-term biochemical outcome, suggesting that novel hypoxic strategies should be investigated.

  8. Predicting the long-term durability of hemp-lime renders in inland and coastal areas using Mediterranean, Tropical and Semi-arid climatic simulations.

    PubMed

    Arizzi, Anna; Viles, Heather; Martín-Sanchez, Inés; Cultrone, Giuseppe

    2016-01-15

    Hemp-based composites are eco-friendly building materials as they improve energy efficiency in buildings and entail low waste production and pollutant emissions during their manufacturing process. Nevertheless, the organic nature of hemp enhances the bio-receptivity of the material, with likely negative consequences for its long-term performance in the building. The main purpose of this study was to study the response at macro- and micro-scale of hemp-lime renders subjected to weathering simulations in an environmental cabinet (one year was condensed in twelve days), so as to predict their long-term durability in coastal and inland areas with Mediterranean, Tropical and Semi-arid climates, also in relation with the lime type used. The simulated climatic conditions caused almost unnoticeable mass, volume and colour changes in hemp-lime renders. No efflorescence or physical breakdown was detected in samples subjected to NaCl, because the salt mainly precipitates on the surface of samples and is washed away by the rain. Although there was no visible microbial colonisation, alkaliphilic fungi (mainly Penicillium and Aspergillus) and bacteria (mainly Bacillus and Micrococcus) were isolated in all samples. Microbial growth and diversification were higher under Tropical climate, due to heavier rainfall. The influence of the bacterial activity on the hardening of samples has also been discussed here and related with the formation and stabilisation of vaterite in hemp-lime mixes. This study has demonstrated that hemp-lime renders show good durability towards a wide range of environmental conditions and factors. However, it might be useful to take some specific preventive and maintenance measures to reduce the bio-receptivity of this material, thus ensuring a longer durability on site.

  9. Usefulness of the platelet-to-lymphocyte ratio in predicting long-term cardiovascular mortality in patients with peripheral arterial occlusive disease

    PubMed Central

    Erturk, Mehmet; Cakmak, Huseyin Altug; Kalkan, Ali Kemal; Akturk, Ibrahim Faruk; Yalcin, Ahmet Arif; Uygur, Begum; Bulut, Umit; Oz, Kursat

    2017-01-01

    Introduction Inflammation and increased platelet activation play a crucial role in the initiation and progression of atherosclerosis. Platelet-to-lymphocyte ratio (PLR) has recently been reported as a new independent predictor for major adverse cardiovascular events in cardiovascular diseases. Aim To investigate the relation between PLR and cardiovascular mortality in patients with intermittent claudication or critical limb ischemia (CLI) or both. Material and methods In our retrospective study, 602 consecutive patients who were admitted to a large tertiary hospital with the diagnosis of symptomatic peripheral arterial occlusive disease (PAOD) were included. Patients were divided into two groups according to their PLR as follows: high PLR (PLR > 142) and low PLR (PLR ≤ 142) groups. Results During the follow-up period (median: 33.8 months (interquartile range: 21–45)), 131 deaths occurred out of 602 (21.8%) patients. Cardiovascular mortality was found to be significantly higher in the high PLR group compared to the low PLR group (31.6% vs. 17.2 %; p < 0.001). Even after adjustment for various risk factors, PLR > 142 and age were found to be independent predictors of long-term cardiovascular mortality in Cox regression analysis (hazard ratios (95% confidence interval): 1.03 (1.01–1.04) and 1.04 (1.02–1.06), p < 0.001 and p < 0.001, respectively). Conclusions Platelet-to-lymphocyte ratio, which is one of the parameters of routine complete blood count, reflects increased inflammatory status, platelet activation and aggregation. PLR is a cheap and readily available marker that has the ability to improve risk stratification provided by conventional risk scores in predicting long-term cardiovascular mortality in PAOD. PMID:28344615

  10. The development of methods for the prediction of primary creep behavior in metals

    NASA Technical Reports Server (NTRS)

    Zerwekh, R. P.

    1978-01-01

    The applicability of a thermodynamic constitutive theory of deformation to the prediction of primary creep and creep strain relaxation behavior in metals is examined. Constitutive equations derived from the theory are subjected to a parametric analysis in order to determine the influence of several parameters on the curve forms generated by the equations. A computer program is developed which enables the solution of a generalized constitutive equation using experimental data as input. Several metals were tested to form a data base of primary creep and relaxation behavior. The extent to which these materials conformed to the constitutive equation showed wide variability, with the alloy Ti-6Al-4V exhibiting the most consistent results. Accordingly, most of the analysis is concentrated upon data from that alloy, although creep and relaxation data from all the materials tested are presented. Experimental methods are outlined as well as some variations in methods of analysis. Various theoretical and practical implications of the work are discussed.

  11. Loose-coupling a cellular automaton model and GIS: Long-term urban growth prediction for San Francisco and Washington/Baltimore

    USGS Publications Warehouse

    Clarke, Keith; Gaydos, Leonard

    1998-01-01

    Prior research developed a cellular automaton model, that was calibrated by using historical digital maps of urban areas and can be used to predict the future extent of an urban area. The model has now been applied to two rapidly growing, but remarkably different urban areas: the San Francisco Bay region in California and the Washington/Baltimore corridor in the Eastern United States. This paper presents the calibration and prediction results for both regions, reviews their data requirements, compares the differences in the initial configurations and control parameters for the model in the two settings, and discusses the role of GIS in the applications. The model has generated some long term predictions that appear useful for urban planning and are consistent with results from other models and observations of growth. Although the GIS was only loosely coupled with the model, the model's provision of future urban patterns as data layers for GIS description and analysis is an important outcome of this type of calculation.

  12. Loose-coupling a cellular automaton model and GIS: long-term urban growth prediction for San Francisco and Washington/Baltimore

    USGS Publications Warehouse

    Clarke, K.C.; Gaydos, L.J.

    1998-01-01

    Prior research developed a cellular automaton model, that was calibrated by using historical digital maps of urban areas and can be used to predict the future extent of an urban area. The model has now been applied to two rapidly growing, but remarkably different urban areas: the San Francisco Bay region in California and the Washington/Baltimore corridor in the Eastern United States. This paper presents the calibration and prediction results for both regions, reviews their data requirements, compares the differences in the initial configurations and control parameters for the model in the two settings, and discusses the role of GIS in the applications. The model has generated some long term predictions that appear useful for urban planning and are consistent with results from other models and observations of growth. Although the GIS was only loosely coupled with the model, the model's provision of future urban patterns as data layers for GIS description and analysis is an important outcome of this type of calculation.

  13. Creep-Fatigue Relationsihps in Electroactive Polymer Systems and Predicted Effects in an Actuator Design

    NASA Technical Reports Server (NTRS)

    Vinogradov, Aleksandra M.; Ihlefeld, Curtis M.; Henslee, Issac

    2009-01-01

    The paper concerns the time-dependent behavior of electroactive polymers (EAP) and their use in advanced intelligent structures for space exploration. Innovative actuator design for low weight and low power valves required in small plants planned for use on the moon for chemical analysis is discussed. It is shown that in-depth understanding of cyclic loading effects observed through accelerated creep rates due to creep-fatigue interaction in polymers is critical in terms of proper functioning of EAP based actuator devices. In the paper, an overview of experimental results concerning the creep properties and cyclic creep response of a thin film piezoelectric polymer polyvinylidene fluoride (PVDF) is presented. The development of a constitutive creep-fatigue interaction model to predict the durability and service life of electroactive polymers is discussed. A novel method is proposed to predict damage accumulation and fatigue life of polymers under oyclic loading conditions in the presence of creep. The study provides a basis for ongoing research initiatives at the NASA Kennedy Space Center in the pursuit of new technologies using EAP as active elements for lunar exploration systems.

  14. Predicted reversal and recovery of surface creep on the Hayward fault following the 1906 San Francisco earthquake

    NASA Astrophysics Data System (ADS)

    Schmidt, D. A.; Bürgmann, R.

    2008-10-01

    Offset cultural features suggest that creep rates along the Hayward fault have remained constant since 1920 until the 1989 Loma Prieta earthquake despite evidence in the earthquake record of an enduring stress shadow after 1906. We re-construct the stressing history on the Hayward fault in order to predict when creep, assumed to have slowed, likely resumed at historical rates. The resumption of creep is dependent on the stressing history imposed from postseismic processes. Basic viscoelastic models produce stress histories that allow creep to resume within a couple decades. A detachment zone model for the Bay Area predicts that creep would not resume for 70+ years after the 1906 earthquake, in disagreement with historical creep observations. The recovery of creep is also advanced by potential left-lateral slip that could have been induced by the 1906 earthquake. Calculations for a friction-less fault suggest that 30-210 mm of left-lateral slip could have occurred.

  15. Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system

    NASA Technical Reports Server (NTRS)

    Davis, J. W.; Cramer, B. A.

    1976-01-01

    A method of analysis was developed for predicting permanent cyclic creep deflections in stiffened panel structures. This method uses creep equations based on cyclic tensile creep tests and a computer program to predict panel deflections as a function of mission cycle. Four materials were investigated - a titanium alloy (Ti-6Al-4V), a cobalt alloy (L605), and two nickel alloys (Rene'41 and TDNiCr). Steady-state and cyclic creep response data were obtained by testing tensile specimens fabricated from thin gage sheet (0.025 and 0.63 cm nominal). Steady-state and cyclic creep equations were developed which describe creep as a function of time, temperature and load. Tests were also performed on subsize (6.35 x 30.5 cm) rib and corrugation stiffened panels. These tests were used to correlate creep responses between elemental specimens and panels. The panel response was analyzed by use of a specially written computer program.

  16. The ‘stochastic river’: The use of budget-capacity modelling as a basis for predicting long-term properties of stratigraphic successions

    NASA Astrophysics Data System (ADS)

    Tipper, John C.

    2007-11-01

    Sediment budget and sedimentation capacity are basic variables that can be used to describe the operation of sedimentation systems of all types; they are generalisations of sediment supply and accommodation. The sediment budget at a site is defined as the net flux of sediment across the site's boundaries; the sedimentation capacity is a measure of the deviation from equilibrium of the sedimentation system concerned. The operation of a sedimentation system is described by first specifying the system's budget-capacity relationship; this is most conveniently done by providing a probabilistic means of predicting budget from capacity. Once the budget-capacity relationship has been specified, a model of the system is constructed; this model follows the general rules put forward in the budget-capacity theory of sedimentation. The model enables the prediction of the patterns of deposition, stasis and erosion that the system will produce in time; from these patterns can then be determined the properties of the stratigraphic successions the system is expected to leave behind. There are many kinds of budget-capacity model. One of these, the 'stochastic river', is particularly useful in predicting long-term regularities in the stratigraphic thickness-time relationship. The 'stochastic river' is a two-dimensional budget-capacity model that mimics an idealised single-channel river. It is composed of a large number of similar sedimentation systems linked together in a chain, with each system fed exclusively from its upstream neighbour. The systems are continually perturbed by having their capacities altered by various external factors; these may be long-term regional-scale factors such as tectonically-induced basement subsidence and isostatic adjustment, as well as short-term local-scale factors such as changes in river discharge. The capacity perturbations are modelled as being driven by a random process; the perturbations of adjacent systems are spatially and temporally coupled

  17. Thermal Aging Study of a Dow Corning SE 1700 Porous Structure Made by Direct Ink Writing: 1-Year Results and Long-Term Predictions

    SciTech Connect

    Small, Ward; Pearson, Mark A.; Maiti, Amitesh; Metz, Thomas R.; Duoss, Eric B.; Wilson, Thomas S.

    2015-11-13

    Dow Corning SE 1700 (reinforced polydimethylsiloxane) porous structures were made by direct ink writing (DIW). The specimens (~50% porosity) were subjected to various compressive strains (15, 30, 45%) and temperatures (room temperature, 35, 50, 70°C) in a nitrogen atmosphere (active purge) for 1 year. Compression set and load retention of the aged specimens were measured periodically during the study. Compression set increased with strain and temperature. After 1 year, specimens aged at room temperature, 35, and 50°C showed ~10% compression set (relative to the applied compressive deflection), while those aged at 70°C showed 20-40%. Due to the increasing compression set, load retention decreased with temperature, ranging from ~90% at room temperature to ~60-80% at 70°C. Long-term compression set and load retention at room temperature were predicted by applying time-temperature superposition (TTS). The predictions show compression set relative to the compressive deflection will be ~10-15% with ~70-90% load retention after 50 years at 15-45% strain, suggesting the material will continue to be mechanically functional. Comparison of the results to previously acquired data for cellular (M97*, M9760, M9763) and RTV (S5370) silicone foams suggests that the SE 1700 DIW porous specimens are on par with, or outperform, the legacy foams.

  18. Improving the Long-Term Stability of Atmospheric Surface Deformation Predictions by Mitigating the Effects of Orography Updates in Operational Weather Forecast Models

    NASA Astrophysics Data System (ADS)

    Dill, Robert; Bergmann-Wolf, Inga; Thomas, Maik; Dobslaw, Henryk

    2016-04-01

    The global numerical weather prediction model routinely operated at the European Centre for Medium-Range Weather Forecasts (ECMWF) is typically updated about two times a year to incorporate the most recent improvements in the numerical scheme, the physical model or the data assimilation procedures into the system for steadily improving daily weather forecasting quality. Even though such changes frequently affect the long-term stability of meteorological quantities, data from the ECMWF deterministic model is often preferred over alternatively available atmospheric re-analyses due to both the availability of the data in near real-time and the substantially higher spatial resolution. However, global surface pressure time-series, which are crucial for the interpretation of geodetic observables, such as Earth rotation, surface deformation, and the Earth's gravity field, are in particular affected by changes in the surface orography of the model associated with every major change in horizontal resolution happened, e.g., in February 2006, January 2010, and May 2015 in case of the ECMWF operational model. In this contribution, we present an algorithm to harmonize surface pressure time-series from the operational ECMWF model by projecting them onto a time-invariant reference topography under consideration of the time-variable atmospheric density structure. The effectiveness of the method will be assessed globally in terms of pressure anomalies. In addition, we will discuss the impact of the method on predictions of crustal deformations based on ECMWF input, which have been recently made available by GFZ Potsdam.

  19. Effects of Aging-Time Reference on the Long Term Behavior of the IM7/K3B Composite

    NASA Technical Reports Server (NTRS)

    Veazie, David R.; Gates, Thomas S.

    1998-01-01

    An analytical study was undertaken to investigate the effects of the time-based shift reference on the long term behavior of the graphite reinforced thermoplastic polyimide composite IM7/K3B at elevated temperature. Creep compliance and the effects of physical aging on the time dependent response was measured for uniaxial loading at several isothermal conditions below the glass transition temperature (T(sub g). Two matrix dominated loading modes, shear and transverse, were investigated in tension and compression. The momentary sequenced creep/aging curves were collapsed through a horizontal (time) shift using the shortest, middle and longest aging time curve as the reference curve. Linear viscoelasticity was used to characterize the creep/recovery behavior and superposition techniques were used to establish the physical aging related material constants. The use of effective time expressions in a laminated plate model allowed for the prediction of long term creep compliance. The effect of using different reference curves with time/aging-time superposition was most sensitive to the physical aging shift rate at lower test temperatures. Depending on the loading mode, the reference curve used can result in a more accurate long term prediction, especially at lower test temperatures.

  20. Quiet eye training aids the long-term learning of throwing and catching in children: Preliminary evidence for a predictive control strategy.

    PubMed

    Miles, C A L; Wood, G; Vine, S J; Vickers, J N; Wilson, M R

    2017-02-01

    Quiet eye training (QET) may be a more effective method for teaching children to catch than traditional training (TT) methods, but it is unclear if the benefits accrued persist in the long term. Thirty children were randomly allocated into a QET or TT group and, while wearing a mobile eye tracker, underwent baseline testing, training and two retention tests over a period of eight weeks, using a validated throw and catch task. During training, movement-related information was provided to both groups, while the QET group received additional instruction to increase the duration of their targeting fixation (QE1) on the wall prior to the throw, and pursuit tracking (QE2) period on the ball prior to catching. In both immediate (R1) and delayed (R2, six weeks later) retention tests, the QET group had a significantly longer QE1 duration and an earlier and longer QE2 duration, compared to the TT group, who revealed no improvements. A performance advantage was also found for the QET compared to the TT group at both R1 and R2, revealing the relatively robust nature of the visuomotor alterations. Regression analyses suggested that only the duration of QE1 predicted variance in catch success post-training, pointing to the importance of a pre-programming visuomotor strategy for successful throw and catch performance.

  1. Expression of type 5 somatostatin receptor in TSH-secreting pituitary adenomas: a possible marker for predicting long-term response to octreotide therapy.

    PubMed

    Yoshihara, Ai; Isozaki, Osamu; Hizuka, Naomi; Nozoe, Yasuko; Harada, Chie; Ono, Masami; Kawamata, Takakazu; Kubo, Osami; Hori, Tomokatsu; Takano, Kazue

    2007-02-01

    In TSH-secreting pituitary adenomas (TSHoma), octreotide (OCT) therapy reduces tumor size and TSH secretion in some cases but not in others. As OCT acts through various types of somatostatin receptors (SSTRs), the different responses of TSHoma to OCT might be explained by the differences of SSTR expression. We therefore studied the expression of subtype-specific SSTR mRNA transcripts in tumor tissues by RT-PCR. Type 2 (SSTR2) mRNA transcripts were detected in all 8 tumors but those of SSTR3 and SSTR5 were demonstrated only in 5 of them. Serum TSH levels were decreased by OCT administration test in all patients but OCT therapy was effective in two patients out of three. SSTR5 mRNA was detected in two tumors from the responder, but not in one tumor that was resistant to OCT. These observations suggest that the temporal decrease of TSH by OCT may be mediated by SSTR2, and that the long term response to OCT therapy may be related with the expression of SSTR5. Therefore, the expression of SSTR5 in TSHoma may be a useful marker for predicting the outcome of the therapy, but further studies with larger numbers of patients are necessary.

  2. Living on the edge: adaptive and plastic responses of the tree Nothofagus pumilio to a long-term transplant experiment predict rear-edge upward expansion.

    PubMed

    Mathiasen, Paula; Premoli, Andrea C

    2016-06-01

    Current climate change affects the competitive ability and reproductive success of many species, leading to local extinctions, adjustment to novel local conditions by phenotypic plasticity or rapid adaptation, or tracking their optima through range shifts. However, many species have limited ability to expand to suitable areas. Altitudinal gradients, with abrupt changes in abiotic conditions over short distances, represent "natural experiments" for the evaluation of ecological and evolutionary responses under scenarios of climate change. Nothofagus pumilio is the tree species which dominates as pure stands the montane forests of Patagonia. We evaluated the adaptive value of variation in quantitative traits of N. pumilio under contrasting conditions of the altitudinal gradient with a long-term reciprocal transplant experimental design. While high-elevation plants show little response in plant, leaf, and phenological traits to the experimental trials, low-elevation ones show greater plasticity in their responses to changing environments, particularly at high elevation. Our results suggest a relatively reduced potential for evolutionary adaptation of high-elevation genotypes, and a greater evolutionary potential of low-elevation ones. Under global warming scenarios of forest upslope migration, high-elevation variants may be outperformed by low-elevation ones during this process, leading to the local extinction and/or replacement of these genotypes. These results challenge previous models and predictions expected under global warming for altitudinal gradients, on which the leading edge is considered to be the upper treeline forests.

  3. A model of compaction creep in carbonates

    NASA Astrophysics Data System (ADS)

    Keszthelyi, Daniel; Jamtveit, Bjørn; Dysthe, Dag Kristian

    2015-04-01

    Rocks in compressional stress conditions are subject to long-term creep deformations. We created a simple conceptual micomechanical model of creep in rocks combining microscopic fracturing and pressure solution. This was then scaled up to macroscopic scale by a statistical mechanical approach to predict strain rate at core scale. The model uses no fitting parameter and have a few input parameters: effective stress, porosity, pore size distribution, temperature and water saturation. Internal parameters are Young's modulus, interfacial energy of wet calcite and dissolution rates of calcite, all of which are measurable independently. Existing long-term creep experiments were used to verify the model which was able to predict the magnitude of the resulting strain in largely different effective stress, temperature and water saturation conditions. The model was also able to predict the compaction of a producing chalk reservoir with a good agreement. Further generalization of the model might function as a general theory of long-term creep of rocks in compressional settings.

  4. Methodology to predict long-term cancer survival from short-term data using Tobacco Cancer Risk and Absolute Cancer Cure models

    NASA Astrophysics Data System (ADS)

    Mould, R. F.; Lederman, M.; Tai, P.; Wong, J. K. M.

    2002-11-01

    Three parametric statistical models have been fully validated for cancer of the larynx for the prediction of long-term 15, 20 and 25 year cancer-specific survival fractions when short-term follow-up data was available for just 1-2 years after the end of treatment of the last patient. In all groups of cases the treatment period was only 5 years. Three disease stage groups were studied, T1N0, T2N0 and T3N0. The models are the Standard Lognormal (SLN) first proposed by Boag (1949 J. R. Stat. Soc. Series B 11 15-53) but only ever fully validated for cancer of the cervix, Mould and Boag (1975 Br. J. Cancer 32 529-50), and two new models which have been termed Tobacco Cancer Risk (TCR) and Absolute Cancer Cure (ACC). In each, the frequency distribution of survival times of defined groups of cancer deaths is lognormally distributed: larynx only (SLN), larynx and lung (TCR) and all cancers (ACC). All models each have three unknown parameters but it was possible to estimate a value for the lognormal parameter S a priori. By reduction to two unknown parameters the model stability has been improved. The material used to validate the methodology consisted of case histories of 965 patients, all treated during the period 1944-1968 by Dr Manuel Lederman of the Royal Marsden Hospital, London, with follow-up to 1988. This provided a follow-up range of 20- 44 years and enabled predicted long-term survival fractions to be compared with the actual survival fractions, calculated by the Kaplan and Meier (1958 J. Am. Stat. Assoc. 53 457-82) method. The TCR and ACC models are better than the SLN model and for a maximum short-term follow-up of 6 years, the 20 and 25 year survival fractions could be predicted. Therefore the numbers of follow-up years saved are respectively 14 years and 19 years. Clinical trial results using the TCR and ACC models can thus be analysed much earlier than currently possible. Absolute cure from cancer was also studied, using not only the prediction models which

  5. Long-term observations of cloud condensation nuclei in the Amazon rain forest - Part 1: Aerosol size distribution, hygroscopicity, and new model parametrizations for CCN prediction

    NASA Astrophysics Data System (ADS)

    Pöhlker, Mira L.; Pöhlker, Christopher; Ditas, Florian; Klimach, Thomas; Hrabe de Angelis, Isabella; Araújo, Alessandro; Brito, Joel; Carbone, Samara; Cheng, Yafang; Chi, Xuguang; Ditz, Reiner; Gunthe, Sachin S.; Kesselmeier, Jürgen; Könemann, Tobias; Lavrič, Jošt V.; Martin, Scot T.; Mikhailov, Eugene; Moran-Zuloaga, Daniel; Rose, Diana; Saturno, Jorge; Su, Hang; Thalman, Ryan; Walter, David; Wang, Jian; Wolff, Stefan; Barbosa, Henrique M. J.; Artaxo, Paulo; Andreae, Meinrat O.; Pöschl, Ulrich

    2016-12-01

    Size-resolved long-term measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted at the remote Amazon Tall Tower Observatory (ATTO) in the central Amazon Basin over a 1-year period and full seasonal cycle (March 2014-February 2015). The measurements provide a climatology of CCN properties characteristic of a remote central Amazonian rain forest site.The CCN measurements were continuously cycled through 10 levels of supersaturation (S = 0.11 to 1.10 %) and span the aerosol particle size range from 20 to 245 nm. The mean critical diameters of CCN activation range from 43 nm at S = 1.10 % to 172 nm at S = 0.11 %. The particle hygroscopicity exhibits a pronounced size dependence with lower values for the Aitken mode (κAit = 0.14 ± 0.03), higher values for the accumulation mode (κAcc = 0.22 ± 0.05), and an overall mean value of κmean = 0.17 ± 0.06, consistent with high fractions of organic aerosol.The hygroscopicity parameter, κ, exhibits remarkably little temporal variability: no pronounced diurnal cycles, only weak seasonal trends, and few short-term variations during long-range transport events. In contrast, the CCN number concentrations exhibit a pronounced seasonal cycle, tracking the pollution-related seasonality in total aerosol concentration. We find that the variability in the CCN concentrations in the central Amazon is mostly driven by aerosol particle number concentration and size distribution, while variations in aerosol hygroscopicity and chemical composition matter only during a few episodes.For modeling purposes, we compare different approaches of predicting CCN number concentration and present a novel parametrization, which allows accurate CCN predictions based on a small set of input data.

  6. Contribution of the long-term care insurance certificate for predicting 1-year all-cause readmission compared with validated risk scores in elderly patients with heart failure

    PubMed Central

    Takahashi, Kayo; Saito, Makoto; Inaba, Shinji; Morofuji, Toru; Aisu, Hiroe; Sumimoto, Takumi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Higaki, Jitsuo

    2016-01-01

    Objectives Readmission is a common and serious problem associated with heart failure (HF). Unfortunately, conventional risk models have limited predictive value for predicting readmission. The recipients of long-term care insurance (LTCI) are frail and have mental and physical impairments. We hypothesised that adjustment of the conventional risk score with an LTCI certificate enables a more accurate appreciation of readmission for HF. Methods We investigated 452 patients with HF who were followed up for 1 year to determine all-cause readmission. We obtained their clinical and socioeconomic data, including LTCI. The three clinical risk scores used in our evaluation were Keenan (2008), Krumholz (2000) and Charlson (1994). We used net reclassification improvement (NRI) to assess the incremental benefit. Results Patients with LTCI were significantly older, and had a higher prevalence of cerebrovascular disease and dementia than those without LTCI. One-year all-cause readmission (n=193, 43%) was significantly associated with all risk scores, receiving LTCI and the category of LTCI. Receiving LTCI was associated with readmission independent of all risk scores (HR, 1.59 to 1.63; all p<0.01). Adding LTCI to all risk scores led to a significantly improved reclassification, which was observed in the subgroup of patients with HF with preserved ejection fraction (≥50%) but not in the subgroup with reduced ejection fraction (<50%). Conclusions Possession of an LTCI certificate was independently associated with 1-year all-cause readmission after adjusting for validated clinical risk scores in patients with HF. Adding LTCI status significantly improved the model performance for readmission risk, particularly in patients with HF and preserved ejection fraction. PMID:27933194

  7. Long-term antibody persistence after vaccination with a 2-dose Havrix (inactivated hepatitis A vaccine): 20 years of observed data, and long-term model-based predictions.

    PubMed

    Theeten, Heidi; Van Herck, Koen; Van Der Meeren, Olivier; Crasta, Priya; Van Damme, Pierre; Hens, Niel

    2015-10-13

    Antibody persistence in two cohorts of adults, who received inactivated hepatitis A (HAV) vaccine (1440El.U; Havrix; GSK Vaccines) according to a 0-6 or 0-12 month schedule in 1992-1993, has been measured annually. After 20 years, >97% of the subjects in both studies were seropositive for anti-HAV antibodies. Geometric mean concentrations in the according-to-protocol cohorts were 312 mIU/ml in 34/36 subjects vaccinated initially at 0-6 months (NCT00289757) and 317 mIU/ml in 85/86 subjects vaccinated at 0-12 months (NCT00291876). Over the whole follow-up period, seven subjects (2+5, respectively) lost circulating anti-HAV antibodies but mounted a strong response after HAV booster administration (1440El.U). Mathematical modelling, which was applied to assess true persistence at Year 20 (accounting for drop-outs and missing data), and to predict longer-term persistence confirmed previous estimates that seropositive anti-HAV levels would persist in ≥95% vaccinees at Year 30 and ≥90% at Year 40. ClinicalTrials.Gov number: NCT00289757/NCT00291876.

  8. Strainrange partitioning life predictions of the long time metal properties council creep-fatigue tests

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.; Halford, G. R.

    1979-01-01

    The method of strainrange partitioning is used to predict the cyclic lives of the Metal Properties Council's long time creep-fatigue interspersion tests of several steel alloys. Comparisons are made with predictions based upon the time- and cycle-fraction approach. The method of strainrange partitioning is shown to give consistently more accurate predictions of cyclic life than is given by the time- and cycle-fraction approach.

  9. Displacement rate dependence of irradiation creep as predicted by the production bias model

    SciTech Connect

    Woo, C.H.

    1996-04-01

    Recently, it has been shown that the non-swelling component of irradiation creep of austenitic stainless steels is relatively independent of temperature but is sensitive to the displacement rate. An earlier model of Lewthwaite and Mosedale anticipated the sensitivity of displacement rate and attributed it to the flux sensitivity of point defect recombination. The point-defect recombination process does not yield the observed temperature dependence, however, although it does predict an inverse dependence of the creep rate on the square root of the displacement rate that was experimentally observed at relatively low temperatures.

  10. Development of a simplified procedure for rocket engine thrust chamber life prediction with creep

    NASA Technical Reports Server (NTRS)

    Badlani, M. L.; Porowski, J. S.; Odonnell, W. J.; Peterson, D. B.

    1983-01-01

    An analytical method for predicting engine thrust chamber life is developed. The method accounts for high pressure differentials and time-dependent creep effects both of which are significant in limiting the useful life of the shuttle main engine thrust chamber. The hot-gas-wall ligaments connecting adjacent cooling channels ribs and separating the coolant flow from the combustion gas are subjected to a high pressure induced primary stress superimposed on an alternating cyclic thermal strain field. The pressure load combined with strain-controlled cycling produces creep ratcheting and consequent bulging and thinning of these ligaments. This mechanism of creep-enhanced ratcheting is analyzed for determining the hot-gas-wall deformation and accumulated strain. Results are confirmed by inelastic finite element analysis. Fatigue and creep rupture damage as well as plastic tensile instability are evaluated as potential failure modes. It is demonstrated for the NARloy Z cases analyzed that when pressure differentials across the ligament are high, creep rupture damage is often the primary failure mode for the cycle times considered.

  11. CA 125 regression after two completed cycles of chemotherapy: lack of prediction for long-term survival in patients with advanced ovarian cancer

    PubMed Central

    Peters-Engl, C; Obermair, A; Heinzl, H; Buxbaum, P; Sevelda, P; Medl, M

    1999-01-01

    The prognostic influence of CA 125 regression between the time point before surgery and after two completed courses of chemotherapy was studied in 210 patients with advanced ovarian cancer, and was compared to other well established prognostic factors. CA 125 blood samples were collected preoperatively (CA 125 pre) and 3 months after surgery (CA 125 3 mo) (at the beginning of the 3rd cycle of chemotherapy). The parameter CA 125 regression defined as log10 (CA 125 3 mo/CA 125 pre) was used for statistical analysis. In a survival analysis using a Cox proportional hazards model, CA 125 regression (P = 0.0001), residual tumour (P = 0.0001), age (P = 0.0095) and grading (P = 0.044) were independent variables, whereas stage of disease, histology, ascites and type of surgery failed to retain significance. Using log10 (CA 125 3 mo/CA 125 pre) as simple covariate in a Cox model showed a hazard ratio of 1.70 (95% confidence interval 1.32–2.19, P = 0.0001). However, a detailed analysis of the interaction of time with the prognostic factor CA 125 regression on survival revealed a strong time-dependent effect with a hazard ratio of more than 6 immediately after two courses of chemotherapy, whereas within approximately 1 year the hazard ratio for the surviving patients dropped quickly to the neutral level of 1. In summary, CA 125 regression is an independent prognostic factor for survival of women with advanced ovarian cancer and allows an identification of a high-risk population among patients with advanced ovarian cancer. However, the discriminating power of serial CA 125 for long-term survival seems to be temporary and prediction of individual patients outcome is far less precise. © 1999 Cancer Research Campaign PMID:10574252

  12. Is it possible to predict long-term success with k-NN? Case study of four market indices (FTSE100, DAX, HANGSENG, NASDAQ)

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Gorban, A. N.; Y Yang, T.

    2014-03-01

    This case study tests the possibility of prediction for 'success' (or 'winner') components of four stock & shares market indices in a time period of three years from 02-Jul-2009 to 29-Jun-2012.We compare their performance ain two time frames: initial frame three months at the beginning (02/06/2009-30/09/2009) and the final three month frame (02/04/2012-29/06/2012).To label the components, average price ratio between two time frames in descending order is computed. The average price ratio is defined as the ratio between the mean prices of the beginning and final time period. The 'winner' components are referred to the top one third of total components in the same order as average price ratio it means the mean price of final time period is relatively higher than the beginning time period. The 'loser' components are referred to the last one third of total components in the same order as they have higher mean prices of beginning time period. We analyse, is there any information about the winner-looser separation in the initial fragments of the daily closing prices log-returns time series.The Leave-One-Out Cross-Validation with k-NN algorithm is applied on the daily log-return of components using a distance and proximity in the experiment. By looking at the error analysis, it shows that for HANGSENG and DAX index, there are clear signs of possibility to evaluate the probability of long-term success. The correlation distance matrix histograms and 2-D/3-D elastic maps generated from ViDaExpert show that the 'winner' components are closer to each other and 'winner'/'loser' components are separable on elastic maps for HANGSENG and DAX index while for the negative possibility indices, there is no sign of separation.

  13. Estimation of long-term stability of mine pillars in underground pit

    SciTech Connect

    Yamashita, S.; Sugimoto, F.; Yamauchi, M.; Furuzumi, M.

    1996-12-01

    Recently in Japan, unexpected degradation (surface subsidence) at old underground quarry sites, such as `Ohya-Ishi` (pumice tuff) pit field has often occurred. At these quarry sites, the excavation was started 20 or 30 years ago with mechanical chain cutter and the Room and Pillar method, and stopped 7 or more years ago. Therefore, a reliable method has been required for an estimation of long term mechanical properties of the rock and for an observation of a stability of rock-pillars or structures. In this study, creep tests under uniaxial compressive load were carried out on the `Ohya-Ishi`, with the aim of estimating the long term stability of the rock. From these results, a creep mechanism of the rock was discussed using the failure mechanism hypothesis proposed by Bieniawski and by others. On this basis, critical time to failure was predicted by the relationship between the logarithm of life time and stress ratio of the sustained axial creep load. Additionally, outline of the monitoring system of AE/MS activity in the field, which have set by the Ohya Aria Consolidate Public Corporation and the others to predict or to prevent the degradation of those residual pillars, is to be reported.

  14. Usefulness of biomarkers for predicting long-term mortality in patients with diabetes mellitus and non-ST-elevation acute coronary syndromes (a GUSTO IV substudy).

    PubMed

    James, Stefan K; Lindahl, Bertil; Timmer, Jorik R; Ottervanger, Jan Paul; Siegbahn, Agneta; Stridsberg, Mats; Armstrong, Paul; Califf, Robert; Wallentin, Lars; Simoons, Maarten L

    2006-01-15

    The present study evaluated whether biomarkers of ischemia, inflammation, myocardial damage, and dysfunction are equally useful in patients who have diabetes mellitus (DM) for prediction of cardiac events in non-ST-elevation acute coronary syndrome (ACS). DM was present in 1,677 of 7,800 patients (21.5%) who had non-ST-elevation ACS and were included in the Fourth Global Utilization of Strategies To Open Occluded Arteries (GUSTO IV) trial. Creatinine, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), troponin T, C-reactive protein, and interleukin-6 were analyzed in serum samples that were obtained at a median of 9.5 hours from symptom onset. One-year mortality rates were 13.5% among patients who had DM (n = 227) and 6.9% among those who did not (n = 418, p < 0.001). The median level of NT-pro-BNP was 2 times as high in patients who had DM, whereas troponin T levels did not differ by DM status. Mortality increased with ascending quartiles of NT-pro-BNP, with 1-year mortality rates of 3.9% (n = 11) in the bottom quartile and 29% (n = 103) in the top quartile. In multivariable analyses, factors that were predictive of 1-year mortality in patients who did not have DM were also significant for those who did. Presence of ST depression > 0.5 mm had the highest odds ratio of 2.3 (95% confidence interval 1.2 to 4.6). NT-pro-BNP levels > 669 ng/L (odds ratio 2.0, 95% confidence interval 1.1 to 3.6) and interleukin-6 levels > 10 ng/L (odds ratio 1.9, 95% confidence interval 1.2 to 3.0) were significant biomarker predictors. In conclusion, DM confers a high long-term mortality in non-ST-elevation ACS. Despite a larger proportion of ST depression and increased levels of NT-pro-BNP and interleukin-6 at admission, these factors provide independent prognostic information that may improve risk stratification and guidance of treatment.

  15. Distinguishing Low-Risk Luminal A Breast Cancer Subtypes with Ki-67 and p53 Is More Predictive of Long-Term Survival.

    PubMed

    Lee, Se Kyung; Bae, Soo Youn; Lee, Jun Ho; Lee, Hyun-Chul; Yi, Hawoo; Kil, Won Ho; Lee, Jeong Eon; Kim, Seok Won; Nam, Seok Jin

    2015-01-01

    Overexpression of p53 is the most frequent genetic alteration in breast cancer. Recently, many studies have shown that the expression of mutant p53 differs for each subtype of breast cancer and is associated with different prognoses. In this study, we aimed to determine the suitable cut-off value to predict the clinical outcome of p53 overexpression and its usefulness as a prognostic factor in each subtype of breast cancer, especially in luminal A breast cancer. Approval was granted by the Institutional Review Board of Samsung Medical Center. We analyzed a total of 7,739 patients who were surgically treated for invasive breast cancer at Samsung Medical Center between Dec 1995 and Apr 2013. Luminal A subtype was defined as ER&PR + and HER2- and was further subclassified according to Ki-67 and p53 expression as follows: luminal A (Ki-67-,p53-), luminal A (Ki-67+, p53-), luminal A (Ki-67 -, p53+) and luminal A (Ki-67+, p53+). Low-risk luminal A subtype was defined as negative for both Ki-67 and p53 (luminal A [ki-67-, p53-]), and others subtypes were considered to be high-risk luminal A breast cancer. A cut-off value of 10% for p53 was a good predictor of clinical outcome in all patients and luminal A breast cancer patients. The prognostic role of p53 overexpression for OS and DFS was only significant in luminal A subtype. The combination of p53 and Ki-67 has been shown to have the best predictive power as calculated by the area under curve (AUC), especially for long-term overall survival. In this study, we have shown that overexpression of p53 and Ki-67 could be used to discriminate low-risk luminal A subtype in breast cancer. Therefore, using the combination of p53 and Ki-67 expression in discriminating low-risk luminal A breast cancer may improve the prognostic power and provide the greatest clinical utility.

  16. An Evaluation of Four Current Models to Predict the Creep-Fatigue Interaction in Rene 95

    DTIC Science & Technology

    1979-06-01

    r’eracti were evaluated for their ability to predict fatigue behrivior at 1200?F (650 9C) of thermomechanical !y processed Rene 93--an advanced nickel-base...strain. This axial strain was controlled during the test by a servo-hydraulic testing machine. The specimen was " heated by an induction coil. A...AFML-TR-79- 4075 L V U rm• AN EVALUATION OF FOUR CURRENT MODELS TO PREDICT THE CREEP- FATIGUE INTERACTION IN RENf 95 Henry L. Bernstein Systems

  17. An Exemplar-Familiarity Model Predicts Short-Term and Long-Term Probe Recognition across Diverse Forms of Memory Search

    ERIC Educational Resources Information Center

    Nosofsky, Robert M.; Cox, Gregory E.; Cao, Rui; Shiffrin, Richard M.

    2014-01-01

    Experiments were conducted to test a modern exemplar-familiarity model on its ability to account for both short-term and long-term probe recognition within the same memory-search paradigm. Also, making connections to the literature on attention and visual search, the model was used to interpret differences in probe-recognition performance across…

  18. Using Psychodynamic, Cognitive Behavioral, and Control Mastery Prototypes to Predict Change: A New Look at an Old Paradigm for Long-Term Single-Case Research

    ERIC Educational Resources Information Center

    Pole, Nnamdi; Ablon, J. Stuart; O'Connor, Lynn E.

    2008-01-01

    This article illustrates a method of testing models of change in individual long-term psychotherapy cases. A depressed client was treated with 208 sessions of control mastery therapy (CMT), an unmanualized approach that integrates elements of psychodynamic therapy (PDT) and cognitive behavioral therapy (CBT). Panels of experts developed prototypes…

  19. Integrated Design Software Predicts the Creep Life of Monolithic Ceramic Components

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Significant improvements in propulsion and power generation for the next century will require revolutionary advances in high-temperature materials and structural design. Advanced ceramics are candidate materials for these elevated-temperature applications. As design protocols emerge for these material systems, designers must be aware of several innate features, including the degrading ability of ceramics to carry sustained load. Usually, time-dependent failure in ceramics occurs because of two different, delayedfailure mechanisms: slow crack growth and creep rupture. Slow crack growth initiates at a preexisting flaw and continues until a critical crack length is reached, causing catastrophic failure. Creep rupture, on the other hand, occurs because of bulk damage in the material: void nucleation and coalescence that eventually leads to macrocracks which then propagate to failure. Successful application of advanced ceramics depends on proper characterization of material behavior and the use of an appropriate design methodology. The life of a ceramic component can be predicted with the NASA Lewis Research Center's Ceramics Analysis and Reliability Evaluation of Structures (CARES) integrated design programs. CARES/CREEP determines the expected life of a component under creep conditions, and CARES/LIFE predicts the component life due to fast fracture and subcritical crack growth. The previously developed CARES/LIFE program has been used in numerous industrial and Government applications.

  20. A study of creep-fatigue life prediction using an artificial neural network

    NASA Astrophysics Data System (ADS)

    Kwon, Young Il; Lim, Byeong Soo

    2001-07-01

    In this study, using AISI 316 stainless steel, creep-fatigue tests were carried out under various test conditions (different total strain ranges and hold times) to verify the applicability of the artificial neural network method to creep-fatigue life prediction. Life prediction was also made by the modified Coffin-Manson method and the modified Ostegren method using 21 data points out of a total 27 experimental data points. The six verification data points were carefully chosen for the purpose of evaluating the predictability of each method. The predicted lives were compared with the experimental results and the following conclusions were obtained within the scope of this study. While the creep-fatigue life prediction by the modified Coffin-Manson method and the modified Ostegren method had average errors of 35.8% and 47.7% respectively, the artificial neural network method had only 15.6%. As a result, the artificial neural network method with the adaptive learning rate was found to be far more accurate and effective than any of the others. The validity of the artificial neural network method for life prediction checked with the six verification data points also proved to be very satisfactory.

  1. Differential Effects on Student Demographic Groups of Using ACT® College Readiness Assessment Composite Score, Act Benchmarks, and High School Grade Point Average for Predicting Long-Term College Success through Degree Completion. ACT Research Report Series, 2013 (5)

    ERIC Educational Resources Information Center

    Radunzel, Justine; Noble, Julie

    2013-01-01

    In this study, we evaluated the differential effects on racial/ethnic, family income, and gender groups of using ACT® College Readiness Assessment Composite score and high school grade point average (HSGPA) for predicting long-term college success. Outcomes included annual progress towards a degree (based on cumulative credit-bearing hours…

  2. Predicting Long-Term College Success through Degree Completion Using ACT[R] Composite Score, ACT Benchmarks, and High School Grade Point Average. ACT Research Report Series, 2012 (5)

    ERIC Educational Resources Information Center

    Radunzel, Justine; Noble, Julie

    2012-01-01

    This study compared the effectiveness of ACT[R] Composite score and high school grade point average (HSGPA) for predicting long-term college success. Outcomes included annual progress towards a degree (based on cumulative credit-bearing hours earned), degree completion, and cumulative grade point average (GPA) at 150% of normal time to degree…

  3. Life prediction methodology for thermal-mechanical fatigue and elevated temperature creep design

    NASA Astrophysics Data System (ADS)

    Annigeri, Ravindra

    Nickel-based superalloys are used for hot section components of gas turbine engines. Life prediction techniques are necessary to assess service damage in superalloy components resulting from thermal-mechanical fatigue (TMF) and elevated temperature creep. A new TMF life model based on continuum damage mechanics has been developed and applied to IN 738 LC substrate material with and without coating. The model also characterizes TMF failure in bulk NiCoCrAlY overlay and NiAl aluminide coatings. The inputs to the TMF life model are mechanical strain range, hold time, peak cycle temperatures and maximum stress measured from the stabilized or mid-life hysteresis loops. A viscoplastic model is used to predict the stress-strain hysteresis loops. A flow rule used in the viscoplastic model characterizes the inelastic strain rate as a function of the applied stress and a set of three internal stress variables known as back stress, drag stress and limit stress. Test results show that the viscoplastic model can reasonably predict time-dependent stress-strain response of the coated material and stress relaxation during hold times. In addition to the TMF life prediction methodology, a model has been developed to characterize the uniaxial and multiaxial creep behavior. An effective stress defined as the applied stress minus the back stress is used to characterize the creep recovery and primary creep behavior. The back stress has terms representing strain hardening, dynamic recovery and thermal recovery. Whenever the back stress is greater than the applied stress, the model predicts a negative creep rate observed during multiple stress and multiple temperature cyclic tests. The model also predicted the rupture time and the remaining life that are important for life assessment. The model has been applied to IN 738 LC, Mar-M247, bulk NiCoCrAlY overlay coating and 316 austenitic stainless steel. The proposed model predicts creep response with a reasonable accuracy for wide range of

  4. A Long-Term Predictive Validity Study: Can the CDI Short Form be Used to Predict Language and Early Literacy Skills Four Years Later?

    ERIC Educational Resources Information Center

    Can, Dilara Deniz; Ginsburg-Block, Marika; Golinkoff, Roberta Michnick; Hirsh-Pasek, Kathryn

    2013-01-01

    This longitudinal study examined the predictive validity of the MacArthur Communicative Developmental Inventories-Short Form (CDI-SF), a parent report questionnaire about children's language development (Fenson, Pethick, Renda, Cox, Dale & Reznick, 2000). Data were first gathered from parents on the CDI-SF vocabulary scores for seventy-six…

  5. Monitoring microstructural evolution of alloy 617 with non-linear acoustics for remaining useful life prediction; multiaxial creep-fatigue and creep-ratcheting

    SciTech Connect

    Lissenden, Cliff; Hassan, Tasnin; Rangari, Vijaya

    2014-10-30

    The research built upon a prior investigation to develop a unified constitutive model for design-­by-­analysis of the intermediate heat exchanger (IHX) for a very high temperature reactor (VHTR) design of next generation nuclear plants (NGNPs). Model development requires a set of failure data from complex mechanical experiments to characterize the material behavior. Therefore uniaxial and multiaxial creep-­fatigue and creep-­ratcheting tests were conducted on the nickel-­base Alloy 617 at 850 and 950°C. The time dependence of material behavior, and the interaction of time dependent behavior (e.g., creep) with ratcheting, which is an increase in the cyclic mean strain under load-­controlled cycling, are major concerns for NGNP design. This research project aimed at characterizing the microstructure evolution mechanisms activated in Alloy 617 by mechanical loading and dwell times at elevated temperature. The acoustic harmonic generation method was researched for microstructural characterization. It is a nonlinear acoustics method with excellent potential for nondestructive evaluation, and even online continuous monitoring once high temperature sensors become available. It is unique because it has the ability to quantitatively characterize microstructural features well before macroscale defects (e.g., cracks) form. The nonlinear acoustics beta parameter was shown to correlate with microstructural evolution using a systematic approach to handle the complexity of multiaxial creep-­fatigue and creep-­ratcheting deformation. Mechanical testing was conducted to provide a full spectrum of data for: thermal aging, tensile creep, uniaxial fatigue, uniaxial creep-­fatigue, uniaxial creep-ratcheting, multiaxial creep-fatigue, and multiaxial creep-­ratcheting. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Optical Microscopy were conducted to correlate the beta parameter with individual microstructure mechanisms. We researched

  6. The effects of physical aging at elevated temperatures on the viscoelastic creep on IM7/K3B

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Feldman, Mark

    1994-01-01

    Physical aging at elevated temperature of the advanced composite IM7/K3B was investigated through the use of creep compliance tests. Testing consisted of short term isothermal, creep/recovery with the creep segments performed at constant load. The matrix dominated transverse tensile and in-plane shear behavior were measured at temperatures ranging from 200 to 230 C. Through the use of time based shifting procedures, the aging shift factors, shift rates and momentary master curve parameters were found at each temperature. These material parameters were used as input to a predictive methodology, which was based upon effective time theory and linear viscoelasticity combined with classical lamination theory. Long term creep compliance test data was compared to predictions to verify the method. The model was then used to predict the long term creep behavior for several general laminates.

  7. Mechanisms Governing the Creep Behavior of High Temperature Alloys for Generation IV Nuclear Energy Systems

    SciTech Connect

    Vasudevan, Vijay; Carroll, Laura; Sham, Sam

    2015-04-06

    This research project, which includes collaborators from INL and ORNL, focuses on the study of alloy 617 and alloy 800H that are candidates for applications as intermediate heat exchangers in GEN IV nuclear reactors, with an emphasis on the effects of grain size, grain boundaries and second phases on the creep properties; the mechanisms of dislocation creep, diffusional creep and cavitation; the onset of tertiary creep; and theoretical modeling for long-term predictions of materials behavior and for high temperature alloy design.

  8. Investigation of the effect of aggregates' morphology on concrete creep properties by numerical simulations

    SciTech Connect

    Lavergne, F.; Sab, K.; Sanahuja, J.; Bornert, M.; Toulemonde, C.

    2015-05-15

    Prestress losses due to creep of concrete is a matter of interest for long-term operations of nuclear power plants containment buildings. Experimental studies by Granger (1995) have shown that concretes with similar formulations have different creep behaviors. The aim of this paper is to numerically investigate the effect of size distribution and shape of elastic inclusions on the long-term creep of concrete. Several microstructures with prescribed size distribution and spherical or polyhedral shape of inclusions are generated. By using the 3D numerical homogenization procedure for viscoelastic microstructures proposed by Šmilauer and Bažant (2010), it is shown that the size distribution and shape of inclusions have no measurable influence on the overall creep behavior. Moreover, a mean-field estimate provides close predictions. An Interfacial Transition Zone was introduced according to the model of Nadeau (2003). It is shown that this feature of concrete's microstructure can explain differences between creep behaviors.

  9. Long-term environmental stewardship.

    SciTech Connect

    Nagy, Michael David

    2010-08-01

    The purpose of this Supplemental Information Source Document is to effectively describe Long-Term Environmental Stewardship (LTES) at Sandia National Laboratories/New Mexico (SNL/NM). More specifically, this document describes the LTES and Long-Term Stewardship (LTS) Programs, distinguishes between the LTES and LTS Programs, and summarizes the current status of the Environmental Restoration (ER) Project.

  10. Long-term urethral catheterisation.

    PubMed

    Turner, Bruce; Dickens, Nicola

    This article discusses long-term urethral catheterisation, focusing on the relevant anatomy and physiology, indications for the procedure, catheter selection and catheter care. It is important that nurses have a good working knowledge of long-term catheterisation as the need for this intervention will increase with the rise in chronic health conditions and the ageing population.

  11. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    NASA Astrophysics Data System (ADS)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-07-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  12. Presynaptic long-term plasticity

    PubMed Central

    Yang, Ying; Calakos, Nicole

    2013-01-01

    Long-term synaptic plasticity is a major cellular substrate for learning, memory, and behavioral adaptation. Although early examples of long-term synaptic plasticity described a mechanism by which postsynaptic signal transduction was potentiated, it is now apparent that there is a vast array of mechanisms for long-term synaptic plasticity that involve modifications to either or both the presynaptic terminal and postsynaptic site. In this article, we discuss current and evolving approaches to identify presynaptic mechanisms as well as discuss their limitations. We next provide examples of the diverse circuits in which presynaptic forms of long-term synaptic plasticity have been described and discuss the potential contribution this form of plasticity might add to circuit function. Finally, we examine the present evidence for the molecular pathways and cellular events underlying presynaptic long-term synaptic plasticity. PMID:24146648

  13. Predicting the long-term (137)Cs distribution in Fukushima after the Fukushima Dai-ichi nuclear power plant accident: a parameter sensitivity analysis.

    PubMed

    Yamaguchi, Masaaki; Kitamura, Akihiro; Oda, Yoshihiro; Onishi, Yasuo

    2014-09-01

    Radioactive materials deposited on the land surface of Fukushima Prefecture from the Fukushima Dai-ichi Nuclear Power Plant explosion is a crucial issue for a number of reasons, including external and internal radiation exposure and impacts on agricultural environments and aquatic biota. Predicting the future distribution of radioactive materials and their fates is therefore indispensable for evaluation and comparison of the effectiveness of remediation options regarding human health and the environment. Cesium-137, the main radionuclide to be focused on, is well known to adsorb to clay-rich soils; therefore its primary transportation mechanism is in the form of soil erosion on the land surface and transport of sediment-sorbed contaminants in the water system. In this study, we applied the Soil and Cesium Transport model, which we have developed, to predict a long-term cesium distribution in the Fukushima area, based on the Universal Soil Loss Equation and simple sediment discharge formulas. The model consists of calculation schemes of soil erosion, transportation and deposition, as well as cesium transport and its future distribution. Since not all the actual data on parameters is available, a number of sensitivity analyses were conducted here to find the range of the output results due to the uncertainties of parameters. The preliminary calculation indicated that a large amount of total soil loss remained in slope, and the residual sediment was transported to rivers, deposited in rivers and lakes, or transported farther downstream to the river mouths. Most of the sediment deposited in rivers and lakes consists of sand. On the other hand, most of the silt and clay portions transported to river were transported downstream to the river mouths. The rate of sediment deposition in the Abukuma River basin was three times as high as those of the other 13 river basins. This may be due to the larger catchment area and more moderate channel slope of the Abukuma River basin

  14. Can Echocardiography, Especially Tricuspid Annular Plane Systolic Excursion Measurement, Predict Pulmonary Hypertension and Improve Prognosis in Patients on Long-Term Dialysis?

    PubMed Central

    Grabysa, Radosław; Wańkowicz, Zofia

    2015-01-01

    In recent years, increasing attention has been paid to pulmonary hypertension (PH) as a strong and independent risk factor for adverse outcome in the population of patients on long-term dialysis. Published results of observational studies indicate that the problem of PH refers mostly to patients on long-term hemodialysis and is less common in peritoneal dialysis patients. The main cause of this complication is proximal location of the arteriovenous fistula, causing chronically increased cardiac output. This paper presents the usefulness of transthoracic echocardiography (TTE) for measurement of the Tricuspid Annular Plane Systolic Excursion (TAPSE) in the early diagnosis of PH in dialysis patients. Echocardiographic diagnosis of pulmonary hypertension with TTE, especially in the case of HD patients, ensures the selection of the proper location for the first arteriovenous fistula and facilitates the decision to switch to peritoneal dialysis or to accelerate the process of qualification for kidney transplantation. PMID:26697754

  15. Search for a more adequate test to predict the long-term migration from the PVC gaskets of metal lids into oily foods in glass jars.

    PubMed

    Graubardt, Nadine; Biedermann, Maurus; Fiselier, Katell; Bolzoni, Luciana; Pedrelli, Turno; Cavalieri, Chiara; Simoneau, Cathérine; Grob, Koni

    2009-07-01

    As shown previously, the conventional testing procedure for simulating long-term migration from the gaskets of metal closures into oily foods does not adequately reflect reality. It appears to be impossible to accelerate migration to the extent that the situation at the end of the shelf life of a product can be anticipated in a few days or weeks. Therefore, we investigated whether long-term migration could be extrapolated from migration rates determined for new lids. Jars were kept in the normal upright position. Since heat treatment may have a strong temporary impact, migration during the initial heating for pasteurization or sterilization and storage at ambient temperature were determined using different lids. Commercial products were recalled from sales points throughout Europe to determine the real migration over extended periods of time and for jars with differing histories. This migration was compared with data from the short-term testing to investigate whether an empirical relationship could be derived. The results show that the short-term test enables the comparison of lids and plasticizers in the initial phase of migration, but that long-term extrapolation presupposes more complex kinetic modeling. The results also demonstrate that the legal relevance of "official" testing methods should be reconsidered to avoid conflict when food contact materials comply with migration limits in the test but not in actual application.

  16. The Potential United Kingdom Energy Gap and Creep Life Prediction Methodologies

    NASA Astrophysics Data System (ADS)

    Evans, Mark

    2013-01-01

    The United Kingdom faces a looming energy gap with around 20 pct of its generating capacity due for closure in the next 10 to 15 years as a result of plant age and new European legislation on environmental protection and safety at work. A number of solutions exist for this problem including the use of new materials so that new plants can operate at higher temperatures, new technologies related to carbon capture and gasification, development of renewable resources, and less obviously the use of accurate models for predicting creep life. This article reviews, with illustrations, some of the more applicable and successful creep prediction methodologies used by academics and industrialists and highlights how these techniques can help alleviate the looming energy gap. The role that these approaches can play in solving the energy gap is highlighted throughout.

  17. Prediction of subsidence resulting from creep closure of solutioned-mined caverns in salt domes

    SciTech Connect

    Neal, J.T.

    1991-01-01

    The prediction of subsidence rates over a range of areal configurations of solution-mined caverns in salt domes is possible, based on some fifty years of history in solution mining. Several approaches contribute to predictions: site-specific observations obtained from subsidence monitoring; numerical modeling, now becoming more practicable and credible; salt-creep data from testing; and rule-of-thumb methods, based on experience. All of these approaches contribute to understanding subsidence but none are totally reliable alone. The example of subsidence occurring at the Strategic Petroleum Reserve sites demonstrates several principles of cavern creep closure, the main cause of the subsidence, and shows that reliable projections of future subsidence are possible. 13 refs., 6 figs.

  18. Prediction of the Creep-Fatigue Lifetime of Alloy 617: An Application of Non-destructive Evaluation and Information Integration

    SciTech Connect

    Vivek Agarwal; Richard Wright; Timothy Roney

    2014-08-01

    A relatively simple method using the nominal constant average stress information and the creep rupture model is developed to predict the creep-fatigue lifetime of Alloy 617, in terms of time to rupture. The nominal constant average stress is computed using the stress relaxation curve. The predicted time to rupture can be converted to number of cycles to failure using the strain range, the strain rate during each cycle, and the hold time information. The predicted creep-fatigue lifetime is validated against the experimental measurements of the creep-fatigue lifetime collected using conventional laboratory creep-fatigue tests. High temperature creep-fatigue tests of Alloy 617 were conducted in air at 950°C with a tensile hold period of up to 1800s in a cycle at total strain ranges of 0.3% and 0.6%. It was observed that the proposed method is conservative in that the predicted lifetime is less than the experimentally determined values. The approach would be relevant to calculate the remaining useful life to a component like a steam generator that might fail by the creep-fatigue mechanism.

  19. A comparison of two contemporary creep-fatigue life prediction methods

    NASA Technical Reports Server (NTRS)

    Mcgaw, M. A.

    1985-01-01

    A comparison of two contemporary approaches to creep fatigue life prediction, the Continuous Damage Mechanics as developed at ONERA, and Strain Range Partitioning, is presented. The general framework of each of these approaches, both being crack initiation life prediction tools, are examined. The basis for, and implications of each predictive method are discussed, relative to the material class(es) for which each was developed, as well as to their general applicability. Evident is a need for critical experiments capable of discriminating among the models; to this end, the question of choice of experiment and material is addressed.

  20. Evaluation of creep-fatigue life-prediction models for the solar central receiver

    NASA Astrophysics Data System (ADS)

    Hyzak, J. M.; Hughes, D. A.

    1981-09-01

    The applicability of several creep fatigue models to life prediction of boiler tubes in a solar central receiver (SCR) was evaluated. The SCR boiler tubes will experience compressive strain dwell loading with hold times up to 6 to 8 hours at temperatures where time dependent deformation will occur. The evaluation criteria include the ability of the model to account for mean stress effects and to be practical in the long life, small strain range regime. A correlation between maximum tensile stress and fatigue life is presented. Using this correlation, compressive dwell behavior is predicted based on continuous cycling data. The limits of this predictive scheme are addressed.

  1. Endochronic theory of transient creep and creep recovery

    NASA Technical Reports Server (NTRS)

    Wu, H. C.; Chen, L.

    1979-01-01

    Short time creep and creep recovery were investigated by means of the endochronic theory of viscoplasticity. It is shown that the constitutive equations for constant-strain-rate stress-strain behavior, creep, creep recovery, and stress relaxation can all ber derived from the general constitutive equation by imposing appropriate constraints. In this unified approach, the effect of strain-hardening is naturally accounted for when describing creep and creep recovery. The theory predicts with reasonable accuracy the creep and creep recovery behaviors for Aluminum 1100-0 at 150 C. It was found that the strain-rate history at prestraining stage affects the subsequent creep. A critical stress was also established for creep recovery. The theory predicts a forward creep for creep recovery stress greater than the critical stress. For creep recovery stress less than the critical stress, the theory then predicts a normal strain recovery.

  2. Long term complications of diabetes

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000327.htm Long-term complications of diabetes To use the sharing features on this page, ... other tests. All these may help you keep complications of diabetes away. You will need to check your blood ...

  3. First principles model of carbonate compaction creep

    NASA Astrophysics Data System (ADS)

    Keszthelyi, Daniel; Dysthe, Dag Kristian; Jamtveit, Bjørn

    2016-05-01

    Rocks under compressional stress conditions are subject to long-term creep deformation. From first principles we develop a simple micromechanical model of creep in rocks under compressional stress that combines microscopic fracturing and pressure solution. This model was then upscaled by a statistical mechanical approach to predict strain rate at core and reservoir scale. The model uses no fitting parameter and has few input parameters: effective stress, temperature, water saturation porosity, and material parameters. Material parameters are porosity, pore size distribution, Young's modulus, interfacial energy of wet calcite, the dissolution, and precipitation rates of calcite, and the diffusion rate of calcium carbonate, all of which are independently measurable without performing any type of deformation or creep test. Existing long-term creep experiments were used to test the model which successfully predicts the magnitude of the resulting strain rate under very different effective stress, temperature, and water saturation conditions. The model was used to predict the observed compaction of a producing chalk reservoir.

  4. NASALife-Component Fatigue and Creep Life Prediction Program and Illustrative Examples

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Mital, Subodh K.; Gyekenyesi, John Z.

    2005-01-01

    NASALife is a life prediction program for propulsion system components made of ceramic matrix composites (CMC) under cyclic thermo-mechanical loading and creep rupture conditions. Although, the primary focus was for CMC components the underlying methodologies are equally applicable to other material systems as well. The program references data for low cycle fatigue (LCF), creep rupture, and static material properties as part of the life prediction process. Multiaxial stresses are accommodated by Von Mises based methods and a Walker model is used to address mean stress effects. Varying loads are reduced by the Rainflow counting method. Lastly, damage due to cyclic loading (Miner s rule) and creep are combined to determine the total damage per mission and the number of missions the component can survive before failure are calculated. Illustration of code usage is provided through example problem of a CMC turbine stator vane made of melt-infiltrated, silicon carbide fiber-reinforced, silicon carbide matrix composite (MI SiC/SiC)

  5. Long-Term Treatment with Citicoline Prevents Cognitive Decline and Predicts a Better Quality of Life after a First Ischemic Stroke

    PubMed Central

    Alvarez-Sabín, Jose; Santamarina, Estevo; Maisterra, Olga; Jacas, Carlos; Molina, Carlos; Quintana, Manuel

    2016-01-01

    Stroke, as the leading cause of physical disability and cognitive impairment, has a very significant impact on patients’ quality of life (QoL). The objective of this study is to know the effect of citicoline treatment in Qol and cognitive performance in the long-term in patients with a first ischemic stroke. This is an open-label, randomized, parallel study of citicoline vs. usual treatment. All subjects were selected 6 weeks after suffering a first ischemic stroke and randomized into parallel arms. Neuropsychological evaluation was performed at 1 month, 6 months, 1 year and 2 years after stroke, and QoL was measured using the EuroQoL-5D questionnaire at 2 years. 163 patients were followed during 2 years. The mean age was 67.5 years-old, and 50.9% were women. Age and absence of citicoline treatment were independent predictors of both utility and poor quality of life. Patients with cognitive impairment had a poorer QoL at 2 years (0.55 vs. 0.66 in utility, p = 0.015). Citicoline treatment improved significantly cognitive status during follow-up (p = 0.005). In conclusion, treatment with long-term citicoline is associated with a better QoL and improves cognitive status 2 years after a first ischemic stroke. PMID:26999113

  6. Long-Term Treatment with Citicoline Prevents Cognitive Decline and Predicts a Better Quality of Life after a First Ischemic Stroke.

    PubMed

    Alvarez-Sabín, Jose; Santamarina, Estevo; Maisterra, Olga; Jacas, Carlos; Molina, Carlos; Quintana, Manuel

    2016-03-16

    Stroke, as the leading cause of physical disability and cognitive impairment, has a very significant impact on patients' quality of life (QoL). The objective of this study is to know the effect of citicoline treatment in Qol and cognitive performance in the long-term in patients with a first ischemic stroke. This is an open-label, randomized, parallel study of citicoline vs. usual treatment. All subjects were selected 6 weeks after suffering a first ischemic stroke and randomized into parallel arms. Neuropsychological evaluation was performed at 1 month, 6 months, 1 year and 2 years after stroke, and QoL was measured using the EuroQoL-5D questionnaire at 2 years. 163 patients were followed during 2 years. The mean age was 67.5 years-old, and 50.9% were women. Age and absence of citicoline treatment were independent predictors of both utility and poor quality of life. Patients with cognitive impairment had a poorer QoL at 2 years (0.55 vs. 0.66 in utility, p = 0.015). Citicoline treatment improved significantly cognitive status during follow-up (p = 0.005). In conclusion, treatment with long-term citicoline is associated with a better QoL and improves cognitive status 2 years after a first ischemic stroke.

  7. Two-liquid-phase system: A promising technique for predicting bioavailability of polycyclic aromatic hydrocarbons in long-term contaminated soils.

    PubMed

    Wang, Congying; Wang, Ziyu; Li, Zengbo; Ahmad, Riaz

    2017-02-01

    A two-liquid-phase system (TLPS), which consisted of soil slurry and silicone oil, was employed to extract polycyclic aromatic hydrocarbons (PAHs) in four long-term contaminated soils in order to assess the bioavailability of PAHs. Extraction kinetics of six PAHs viz. phenanthrene, fluoranthene, pyrene, benzo(a)anthracene, benzo(a)pyrene, dibenzo(a,h)anthrancene were selected to investigate as they covered the susceptible and recalcitrant PAHs in soil. A parallel experiments were also carried out on the microbial degradation of these PAHs in soil with and without biostimulation (by adding (NH4)2HPO4). The rapidly desorbed fraction of fluoranthene, as indicated by the two-fraction model, was found the highest, ranging from 21.4% to 37.4%, whereas dibenzo(a,h)anthrancene was the lowest, ranging from 8.9% to 20.5%. The rapid desorption of selected PAHs was found to be finished within 24 h. The rapidly desorbed fraction of PAHs investigated using TLPS, was significantly correlated (R(2) = 0.95) with that degraded by microorganisms in biostimulation treatment. This suggested that the TLPS-assisted extraction could be a promising technique in determining the bioavailability of aged PAHs in contaminated soils. It also suggested that applying sufficient nutrients in bioremediation of field contaminated soils is crucial. Further work is required to test its application to more hydrophobic organic pollutants in long-term contaminated soils.

  8. Creep fatigue life prediction for engine hot section materials (isotropic)

    NASA Technical Reports Server (NTRS)

    Nelson, R. S.; Levan, G. W.; Schoendorf, J. F.

    1992-01-01

    A series of high temperature strain controlled fatigue tests have been completed to study the effects of thermomechanical fatigue, multiaxial loading, reactive environments, and imposed mean stresses. The baseline alloy used in these tests was cast B1900+Hf (with and without coatings); a small number of tests of wrought INCO 718 are also included. A strong path dependence was demonstrated during the thermomechanical fatigue testing, using in-phase, out-phase, and non-proportional (elliptical and 'dogleg') strain-temperature cycles. The multiaxial tests also demonstrated cycle path to be a significant variable, using both proportional and non-proportional tension-torsion loading. Environmental screening tests were conducted in moderate pressure oxygen and purified argon; the oxygen reduced the specimen lives by two, while the argon testing produced ambiguous data. Both NiCoCrAlY overlay and diffusion aluminide coatings were evaluated under isothermal and TMF conditions; in general, the lives of the coated specimens were higher that those of uncoated specimens. Controlled mean stress TMF tests showed that small mean stress changes could change initiation lives by orders of magnitude; these results are not conservatively predicted using traditional linear damage summation rules. Microstructures were evaluated using optical, SEM and TEM methods.

  9. Prediction and verification of creep behavior in metallic materials and components, for the space shuttle thermal protection system. Volume 1, phase 1: Cyclic materials creep predictions

    NASA Technical Reports Server (NTRS)

    Davis, J. W.; Cramer, B. A.

    1974-01-01

    Cyclic creep response was investigated and design methods applicable to thermal protection system structures were developed. The steady-state (constant temperature and load) and cyclic creep response characteristics of four alloys were studied. Steady-state creep data were gathered through a literature survey to establish reference data bases. These data bases were used to develop empirical equations describing creep as a function of time, temperature, and stress and as a basis of comparison for test data. Steady-state creep tests and tensile cyclic tests were conducted. The following factors were investigated: material thickness and rolling direction; material cyclic creep response under varying loads and temperatures; constant stress and temperature cycles representing flight conditions; changing stresses present in a creeping beam as a result of stress redistribution; and complex stress and temperature profiles representative of space shuttle orbiter trajectories. A computer program was written, applying creep hardening theories and empirical equations for creep, to aid in analysis of test data. Results are considered applicable to a variety of structures which are cyclicly exposed to creep producing thermal environments.

  10. Exploring the role of model-data-fusion approaches in constraining the long term predictability of terrestrial ecosystem carbon fluxes with multi-model ensembles

    NASA Astrophysics Data System (ADS)

    Carvalhais, Nuno

    2014-05-01

    Discrepancies between future projections of land carbon fluxes originate from different process representations, but also from differences in model parameterization. Between model divergence stems mostly from different modeling structures, parameterizations and initial conditions. In addition to the known differences in the mean model behavior under future climate scenarios, there are likely also differences in model responses to increased climate variability, and extreme events, which have yet to be assessed. Here we present an in situ model data fusion experiment to explore the contribution of diverse long-term observations in addressing the divergence in responses to climate variability and extreme events between different modeled projections of ecosystem water and carbon fluxes until 2100. We focus on two forest sites in France - Hesse and Le Bray. At these sites the carbon and water fluxes have been observed for more than ten years using eddy covariance. A consolidated set of flux observations and respective uncertainties is complemented with biometric information on aboveground biomass, biomass increments and soil carbon stocks. These datasets are used as constraints in the inverse parameter optimization of an ensemble of terrestrial biogeochemical models ranging from specific forest models to generic land surface schemes, namely: BASFOR, FöBAAR, JSBACH, LPJ and ORCHIDEE. The set of multiple constraints ensures that the models simulate the responses of ecosystem fluxes to environmental conditions in agreement with ecosystem pools. Despite significant improvements in modeling performance, we observe modest improvements in estimating the interannual variability in carbon fluxes and pools. The divergence in long-term trends until 2100 between models is reduced after optimization. However, an increase in the variability of net ecosystem fluxes is observed, which results from the higher interannual variability in the climate scenarios, as well as the growing

  11. Evaluating the predictability of terrestrial ecosystem carbon fluxes integrating long term eddy-covariance and biometric observations with multi-model ensembles (Invited)

    NASA Astrophysics Data System (ADS)

    Carvalhais, N.; van Oijen, M.; Keenan, T. F.; Macbean, N. L.; Peylin, P. P.; Rammig, A.; Rolinski, S.; Thum, T.; Granier, A.; Loustau, D.; Schuermann, G. J.; Zaehle, S.; Beer, C.; Mahecha, M. D.; Richardson, A. D.; Reichstein, M.

    2013-12-01

    Discrepancies between future projections of land carbon fluxes originate from different process representations, but also from differences in model parameterization. Model parameters are typically drawn from disparate literature sources, individual site measurements, or expert judgment, allowing for large variability in the actual parameters used and thus model functional responses. In addition, differences in meteorological forcing datasets and modeling setups may contribute strongly to differences at inter-annual and longer time scales. Along with the known differences in the mean model behavior under future climate scenarios, there are likely also differences in model responses to increased climate variability, and extreme events, which have yet to be assessed. In this study we developed an in situ model data fusion experiment to explore the contribution of diverse long-term observations in addressing the divergence of modeled projections of ecosystem water and carbon fluxes until 2100, along with responses to climate variability and extreme events. We focus on two forest sites in France - Hesse and Le Bray - for which carbon and water fluxes have been observed for more than ten years using eddy covariance methodology. The consolidated set of eddy covariance observations and respective uncertainties is complemented with biometric information on aboveground biomass, biomass increments and soil carbon stocks. These datasets are simultaneously used as constraints in the inverse parameter optimization of an ensemble of terrestrial biogeochemical models ranging from specific forest models to generic land surface schemes, namely: BASFOR, FöBAAR, JSBACH, LPJ and ORCHIDEE. The experimental setup includes the harmonization of the optimization by forcing and constraining the models with the same observations, and through a common cost function. The set of multiple constraints ensures that the models simulate the responses of ecosystem fluxes to environmental conditions

  12. Steady-State Creep of Rock Salt: Improved Approaches for Lab Determination and Modelling

    NASA Astrophysics Data System (ADS)

    Günther, R.-M.; Salzer, K.; Popp, T.; Lüdeling, C.

    2015-11-01

    Actual problems in geotechnical design, e.g., of underground openings for radioactive waste repositories or high-pressure gas storages, require sophisticated constitutive models and consistent parameters for rock salt that facilitate reliable prognosis of stress-dependent deformation and associated damage. Predictions have to comprise the active mining phase with open excavations as well as the long-term development of the backfilled mine or repository. While convergence-induced damage occurs mostly in the vicinity of openings, the long-term behaviour of the backfilled system is dominated by the damage-free steady-state creep. However, because in experiments the time necessary to reach truly stationary creep rates can range from few days to years, depending mainly on temperature and stress, an innovative but simple creep testing approach is suggested to obtain more reliable results: A series of multi-step tests with loading and unloading cycles allows a more reliable estimate of stationary creep rate in a reasonable time. For modelling, we use the advanced strain-hardening approach of Günther-Salzer, which comprehensively describes all relevant deformation properties of rock salt such as creep and damage-induced rock failure within the scope of an unified creep ansatz. The capability of the combination of improved creep testing procedures and accompanied modelling is demonstrated by recalculating multi-step creep tests at different loading and temperature conditions. Thus reliable extrapolations relevant to in-situ creep rates (10^{-9} to 10^{-13} s^{-1}) become possible.

  13. Does anxiety predict the use of urgent care by people with long term conditions? A systematic review with meta-analysis

    PubMed Central

    Blakeley, Claire; Blakemore, Amy; Hunter, Cheryl; Guthrie, Else; Tomenson, Barbara; Dickens, Chris

    2014-01-01

    Objective The role of anxiety in the use of urgent care in people with long term conditions is not fully understood. A systematic review was conducted with meta-analysis to examine the relationship between anxiety and future use of urgent healthcare among individuals with one of four long term conditions: diabetes; coronary heart disease, chronic obstructive pulmonary disease and asthma. Methods Electronic searches of MEDLINE, EMBASE, PSYCINFO, CINAHL, the British Nursing Library and the Cochrane Library were conducted These searches were supplemented by hand-searching bibliographies, citation tracing eligible studies and asking experts within the field about relevant studies. Studies were eligible for inclusion if they: a) used a standardised measure of anxiety, b) used prospective cohort design, c) included adult patients diagnosed with coronary heart disease (CHD), asthma, diabetes or chronic obstructive pulmonary disease (COPD), d) assessed urgent healthcare use prospectively. Data regarding participants, methodology, and association between anxiety and urgent care use was extracted from studies eligible for inclusion. Odds ratios were calculated for each study and pooled using random effects models. Results 8 independent studies were identified for inclusion in the meta-analysis, with a total of 28,823 individual patients. Pooled effects indicate that anxiety is not associated with an increase in the use of urgent care (OR = 1.078, p = 0.476), regardless of the type of service, or type of medical condition. Conclusions Anxiety is not associated with increased use of urgent care. This finding is in contrast to similar studies which have investigated the role of depression as a risk factor for use of urgent care. PMID:25149033

  14. Long-term final void salinity prediction for a post-mining landscape in the Hunter Valley, New South Wales, Australia

    NASA Astrophysics Data System (ADS)

    Hancock, G. R.; Wright, A.; de Silva, H.

    2005-02-01

    Opencast mining alters surface and subsurface hydrology of a landscape both during and post-mining. At mine closure, following opencast mining in mines with low overburden to coal ratios, a void is left in the final landform. This final void is the location of the active mine pit at closure. Voids are generally not infilled within the mines' lifetime, because of the prohibitive cost of earthwork operations, and they become post-mining water bodies or pit lakes. Water quality is a significant issue for pit lakes. Groundwater within coal seams and associated rocks can be saline, depending on the nature of the strata and groundwater circulation patterns. This groundwater may be preferentially drawn to and collected in the final void. Surface runoff to the void will not only collect salts from rainfall and atmospheric fallout, but also from the ground surface and the weathering of fresh rock. As the void water level rises, its evaporative surface area increases, concentrating salts that are held in solution. This paper presents a study of the long term, water quality trends in a post-mining final void in the Hunter Valley, New South Wales, Australia. This process is complex and occurs long term, and modelling offers the only method of evaluating water quality. Using available geochemical, climate and hydrogeological data as inputs into a mass-balance model, water quality in the final void was found to increase rapidly in salinity through time (2452 to 8909 mg l-1 over 500 years) as evaporation concentrates the salt in the void and regional groundwater containing high loads of salt continues to flow into the void.

  15. Aerodynamic-thermomechanic coupling and creep-fatigue damage prediction. Part B: Thermomechanic investigation

    SciTech Connect

    Bruchet, P.

    1995-12-31

    The purpose of this paper is creep-fatigue damage prediction during the cold start-up of a 250 MW steam turbine high pressure rotor. Calculations were performed taking into account aerodynamic and thermal effects. Aerodynamic effects were obtained from a calculation of the bucket root and diaphragm packing leakage flow performed with the finite elements code N3S (see Part A : Aerodynamic investigation). Then, thermomechanical calculations were undertaken with the finite elements mechanical code ASTER and with the thermal boundary conditions previously obtained. These calculations pointed out plastified zones in the first two stages of the HP rotor. Consequently, it was necessary to estimate the thermal fatigue life reduction due to the start-up as well as the creep damage. These calculations were performed using frequency dependent Manson-Coffin curves for fatigue damage and Larson-Miller curves for creep damage. The start-up influence on the rotor residual life was particularly studied and interesting results are available.

  16. Creep Effects in Pultruded FRP Beams

    NASA Astrophysics Data System (ADS)

    Boscato, G.; Casalegno, C.; Russo, S.

    2016-03-01

    The paper presents results of two creep tests on pultruded open-section GFRP beams aimed to evaluate the long-term deformations, the residual deflection after unloading, and the influence of creep strains on the flexuraltorsional buckling phenomenon. Two beams were subjected to a constant load for about one year. Then one of the beams was unloaded to evaluate its residual deflection. For the other beam, the load was increased up to failure, and the residual buckling strength was compared with that of a similar beam tested up to failure. The parameters of the Findley power law are evaluated, and the experimental results are compared with those of numerical analyses and with available formulations for prediction of the time-dependent properties of composite beams. Results of the investigation testify, in particular, to a noninsignificant time-dependent increment in deflections of the beams and to a significant reduction in their buckling strength due to creep deformations.

  17. Differences in ward-to-cath lab systolic blood pressure predicts long-term adverse outcomes after drug-eluting stent implantation.

    PubMed

    Her, Ae-Young; Ann, Soe Hee; Lee, Jun Ho; Kim, Jong Min; Kim, Yong Hoon; Garg, Scot; Singh, Gillian Balbir; Shin, Eun-Seok

    2015-11-01

    We sought to investigate the effect of ward-to-cath lab blood pressure (BP) differences on long-term clinical outcomes in patients undergoing percutaneous coronary intervention (PCI) with drug-eluting stent (DES). There are limited data available on the association between PCI with DES and BP differences on long-term clinical outcomes. This study enrolled 994 patients who underwent PCI with DES from March 2003 to August 2007. Resting BP was measured in a ward environment before transfer to the cardiac catheterization lab (cath lab), and again when the patient was laid down on the cath lab table. Patients were divided into two groups according to the difference in ward-to-cath lab systolic BP. Large difference group (n = 383) was defined as the absolute systolic difference of >20 mmHg and small difference group (n = 424) as the absolute systolic difference of ≤20 mmHg. The primary endpoints were all-cause mortality, cardiac death, nonfatal myocardial infarction and stroke. A total of 807 patients (mean age 60 ± 10 years, 522 males) received follow-up for 5.1 ± 2.4 years. The rate of all-cause mortality was significantly higher in the large difference group compared to the small difference group (6.6 vs. 2.8 %; adjusted hazard ratio (HR) 2.43; 95 % confidence interval (CI) 1.22-4.83; p = 0.012). There were higher cardiac deaths seen in the large difference group compared to the small difference group (3.9 vs. 1.4 %; adjusted HR 2.84; 95 % CI 1.1-7.31; p = 0.031). Stroke (2.4 vs. 1.2 %, p = 0.125) and TVR (3.7 vs. 1.7 %, p = 0.051) had higher trends in the large difference group compared to the small difference group. The composite of primary endpoints (all-cause mortality, cardiac death, nonfatal MI and stroke) occurred more frequently in the large difference group compared to the small difference group (10.0 vs. 6.4 %; adjusted HR 1.71; 95 % CI 1.04-2.81; p = 0.033). A difference in ward-to-cath lab systolic BP of >20 mmHg may contribute to increased adverse

  18. Long-term parenteral nutrition

    PubMed Central

    Ladefoged, Karin; Jarnum, Stig

    1978-01-01

    Nineteen patients (11 women and eight men) aged 20-68 received long-term parenteral nutrition, mostly at home, for six to 63 months (mean 19 months). Indications for LTPN were extensive, active Crohn's disease in three patients, intestinocutaneous fistulas in three, and short-bowel syndrome in the remaining 13 patients. Subclavian or intra-atrial (Broviac) catheters were most commonly used, for which the average life was four and seven months respectively. Complications of long-term parenteral nutrition included pneumothorax in four out of 48 subclavian vein punctures. Catheter-induced thrombosis of central veins was shown by phlebography 17 times in nine patients, and eight episodes of total occlusion occurred. Two of these patients had pulmonary infarction. Nineteen episodes of catheter sepsis occurred in 11 patients, but only one was fatal. Complications related to intestinal disease included intra-abdominal abscesses and intestinal fistulas, and disturbances of liver function. Five patients died, though in only two was death related to long-term parenteral nutrition. One of these patients died from catheter sepsis, the other had subdural haematoma possibly caused by anticoagulant treatment. Eight of the 14 surviving patients still needed parenteral nutrition. All received a disability pension, but six had an acceptable quality of life with almost normal social activities. Despite problems such as difficulties in maintaining standardised infusion programmes, it was concluded that long-term parenteral nutrition at home is practicable and consistent with an acceptable quality of life. ImagesFIG 2 PMID:98199

  19. Application of strainrange partitioning to the prediction of MPC creep-fatigue data for 2 1/4 Cr-1Mo steel

    NASA Technical Reports Server (NTRS)

    Saltsman, J. F.; Halford, G. R.

    1976-01-01

    Strainrange partitioning is used to predict the long time cyclic lives of the metal properties council (MPC) creep-fatigue interspersion and cyclic creep-rupture tests conducted with annealed 2 1/4 Cr-1Mo steel. Observed lives agree with predicted lives within factors of two. The strainrange partitioning life relations used for the long time predictions were established from short time creep-fatigue data generated at NASA-Lewis on the same heat of material.

  20. Creep fatigue life prediction for engine hot section materials (isotropic): Fourth year progress review

    NASA Technical Reports Server (NTRS)

    Nelson, Richard S.; Schoendorf, John F.

    1986-01-01

    As gas turbine technology continues to advance, the need for advanced life prediction methods for hot section components is becoming more and more evident. The complex local strain and temperature histories at critical locations must be accurately interpreted to account for the effects of various damage mechanisms (such as fatigue, creep, and oxidation) and their possible interactions. As part of the overall NASA HOST effort, this program is designed to investigate these fundamental damage processes, identify modeling strategies, and develop practical models which can be used to guide the early design and development of new engines and to increase the durability of existing engines.

  1. Application of the cracked pipe element to creep crack growth prediction

    SciTech Connect

    Brochard, J.; Charras, T.

    1997-04-01

    Modifications to a computer code for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading are very briefly described. The modifications extend the capabilities of the CASTEM2000 code to the determination of fracture parameters under creep conditions. The main advantage of the approach is that thermal loads can be evaluated as secondary stresses. The code is applicable to piping systems for which crack propagation predictions differ significantly depending on whether thermal stresses are considered as primary or secondary stresses.

  2. A proteinuria cut-off level of 0.7 g/day after 12 months of treatment best predicts long-term renal outcome in lupus nephritis: data from the MAINTAIN Nephritis Trial

    PubMed Central

    Tamirou, Farah; Lauwerys, Bernard R; Dall'Era, Maria; Mackay, Meggan; Rovin, Brad; Cervera, Ricard; Houssiau, Frédéric A

    2015-01-01

    Background Although an early decrease in proteinuria has been correlated with good long-term renal outcome in lupus nephritis (LN), studies aimed at defining a cut-off proteinuria value are missing, except a recent analysis performed on patients randomised in the Euro-Lupus Nephritis Trial, demonstrating that a target value of 0.8 g/day at month 12 optimised sensitivity and specificity for the prediction of good renal outcome. The objective of the current work is to validate this target in another LN study, namely the MAINTAIN Nephritis Trial (MNT). Methods Long-term (at least 7 years) renal function data were available for 90 patients randomised in the MNT. Receiver operating characteristic curves were built to test the performance of proteinuria measured within the 1st year as short-term predictor of long-term renal outcome. We calculated the positive and negative predictive values (PPV, NPV). Results After 12 months of treatment, achievement of a proteinuria <0.7 g/day best predicted good renal outcome, with a sensitivity and a specificity of 71% and 75%, respectively. The PPV was high (94%) but the NPV low (29%). Addition of the requirement of urine red blood cells ≤5/hpf as response criteria at month 12 reduced sensitivity from 71% to 41%. Conclusions In this cohort of mainly Caucasian patients suffering from a first episode of LN in most cases, achievement of a proteinuria <0.7 g/day at month 12 best predicts good outcome at 7 years and inclusion of haematuria in the set of criteria at month 12 undermines the sensitivity of early proteinuria decrease for the prediction of good outcome. The robustness of these conclusions stems from the very similar results obtained in two distinct LN cohorts. Trial registration number: NCT00204022. PMID:26629352

  3. Long-term data archiving

    SciTech Connect

    Moore, David Steven

    2009-01-01

    Long term data archiving has much value for chemists, not only to retain access to research and product development records, but also to enable new developments and new discoveries. There are some recent regulatory requirements (e.g., FDA 21 CFR Part 11), but good science and good business both benefit regardless. A particular example of the benefits of and need for long term data archiving is the management of data from spectroscopic laboratory instruments. The sheer amount of spectroscopic data is increasing at a scary rate, and the pressures to archive come from the expense to create the data (or recreate it if it is lost) as well as its high information content. The goal of long-term data archiving is to save and organize instrument data files as well as any needed meta data (such as sample ID, LIMS information, operator, date, time, instrument conditions, sample type, excitation details, environmental parameters, etc.). This editorial explores the issues involved in long-term data archiving using the example of Raman spectral databases. There are at present several such databases, including common data format libraries and proprietary libraries. However, such databases and libraries should ultimately satisfy stringent criteria for long term data archiving, including readability for long times into the future, robustness to changes in computer hardware and operating systems, and use of public domain data formats. The latter criterion implies the data format should be platform independent and the tools to create the data format should be easily and publicly obtainable or developable. Several examples of attempts at spectral libraries exist, such as the ASTM ANDI format, and the JCAMP-DX format. On the other hand, proprietary library spectra can be exchanged and manipulated using proprietary tools. As the above examples have deficiencies according to the three long term data archiving criteria, Extensible Markup Language (XML; a product of the World Wide Web

  4. Annual Rates on Seismogenic Italian Sources with Models of Long-Term Predictability for the Time-Dependent Seismic Hazard Assessment In Italy

    NASA Astrophysics Data System (ADS)

    Murru, Maura; Falcone, Giuseppe; Console, Rodolfo

    2016-04-01

    The present study is carried out in the framework of the Center for Seismic Hazard (CPS) INGV, under the agreement signed in 2015 with the Department of Civil Protection for developing a new model of seismic hazard of the country that can update the current reference (MPS04-S1; zonesismiche.mi.ingv.it and esse1.mi.ingv.it) released between 2004 and 2006. In this initiative, we participate with the Long-Term Stress Transfer (LTST) Model to provide the annual occurrence rate of a seismic event on the entire Italian territory, from a Mw4.5 minimum magnitude, considering bins of 0.1 magnitude units on geographical cells of 0.1° x 0.1°. Our methodology is based on the fusion of a statistical time-dependent renewal model (Brownian Passage Time, BPT, Matthews at al., 2002) with a physical model which considers the permanent effect in terms of stress that undergoes a seismogenic source in result of the earthquakes that occur on surrounding sources. For each considered catalog (historical, instrumental and individual seismogenic sources) we determined a distinct rate value for each cell of 0.1° x 0.1° for the next 50 yrs. If the cell falls within one of the sources in question, we adopted the respective value of rate, which is referred only to the magnitude of the event characteristic. This value of rate is divided by the number of grid cells that fall on the horizontal projection of the source. If instead the cells fall outside of any seismic source we considered the average value of the rate obtained from the historical and the instrumental catalog, using the method of Frankel (1995). The annual occurrence rate was computed for any of the three considered distributions (Poisson, BPT and BPT with inclusion of stress transfer).

  5. Symptoms of depression and anxiety predict treatment response and long-term physical health outcomes in rheumatoid arthritis: secondary analysis of a randomized controlled trial

    PubMed Central

    Norton, Sam; Scott, David L.; Steer, Sophia; Hotopf, Matthew

    2016-01-01

    Objective. The aim of this analysis is to examine the longitudinal impact of symptoms of depression/anxiety on treatment response, long-term disease activity and physical disability in RA. Methods. Secondary analysis of clinical trial data was performed. Data were collected at baseline and at 6-monthly intervals for 2 years. The EuroQoL (EQ-5DTM) indicated depression/anxiety symptom severity. Our primary outcomes of interest were (i) DAS-28 and (ii) physical disability measured via the HAQ. Secondary outcomes were: tender and swollen joint counts, patient global assessment, ESR and odds of reaching clinical remission. Multilevel models were used to assess the impact of baseline and persistent depression/anxiety on outcomes over 2 years. Results. Data from 379 patients were included. After adjusting for covariates, baseline depression/anxiety symptoms were associated with increased DAS-28 outcomes and increased tender joint counts. Persistent depression/anxiety symptoms were associated with increased DAS-28 scores, HAQ scores, tender joint counts and patient global assessment of disease activity, and reduced odds of reaching clinical remission. Patients with symptoms of depression/anxiety at baseline also showed a 50% reduction in prednisolone treatment effect, in comparison with patients with no symptoms of depression/anxiety at baseline. Conclusion. Baseline and persistent symptoms of depression/anxiety are associated with poorer health outcomes over time, as well as reduced treatment response. Mental health should be routinely measured both in clinical practice and in research, and managed alongside rheumatological disease to optimize health outcomes. Further research is required to examine whether treatment of mental disorders can improve rheumatological outcomes. PMID:26350486

  6. Creep-rupture reliability analysis

    NASA Technical Reports Server (NTRS)

    Peralta-Duran, A.; Wirsching, P. H.

    1984-01-01

    A probabilistic approach to the correlation and extrapolation of creep-rupture data is presented. Time temperature parameters (TTP) are used to correlate the data, and an analytical expression for the master curve is developed. The expression provides a simple model for the statistical distribution of strength and fits neatly into a probabilistic design format. The analysis focuses on the Larson-Miller and on the Manson-Haferd parameters, but it can be applied to any of the TTP's. A method is developed for evaluating material dependent constants for TTP's. It is shown that optimized constants can provide a significant improvement in the correlation of the data, thereby reducing modelling error. Attempts were made to quantify the performance of the proposed method in predicting long term behavior. Uncertainty in predicting long term behavior from short term tests was derived for several sets of data. Examples are presented which illustrate the theory and demonstrate the application of state of the art reliability methods to the design of components under creep.

  7. A parametric physics based creep life prediction approach to gas turbine blade conceptual design

    NASA Astrophysics Data System (ADS)

    Smith, Marcus Edward Brockbank

    The required useful service lives of gas turbine components and parts are naturally one of the major design constraints limiting the gas turbine design space. For example, the required service life of a turbine blade limits the firing temperature in the combustor, which in turn limits the performance of the gas turbine. For a cooled turbine blade, it also determines the necessary cooling flow, which has a strong impact on the turbine efficiency. In most gas turbine design practices, the life prediction is only emphasized during or after the detailed design has been completed. Limited life prediction efforts have been made in the early design stages, but these efforts capture only a few of the necessary key factors, such as centrifugal stress. Furthermore, the early stage prediction methods are usually hard coded in the gas turbine system design tools and hidden from the system designer's view. The common failure mechanisms affecting the service life, such as creep, fatigue and oxidation, are highly sensitive to the material temperatures and/or stresses. Calculation of these temperatures and stresses requires that the geometry, material properties, and operating conditions be known; information not typically available in early stages of design. Even without awareness of the errors, the resulting inaccuracy in the life prediction may mislead the system designers when examining a design space which is bounded indirectly by the inaccurate required life constraints. Furthermore, because intensive creep lifing analysis is possible only towards the end of the design process, any errors or changes will cost the engine manufacturer significant money; money that could be saved if more comprehensive creep lifing predictions were possible in the early stages of design. A rapid, physics-based life prediction method could address this problem by enabling the system designer to investigate the design space more thoroughly and accurately. Although not meant as a final decision

  8. Factors predictive of the short- and long-term efficacy of growth hormone treatment in prepubertal children with chronic renal failure. The German Study Group for Growth Hormone Treatment in Chronic Renal Failure.

    PubMed

    Haffner, D; Wühl, E; Schaefer, F; Nissel, R; Tönshoff, B; Mehls, O

    1998-10-01

    To evaluate the growth-stimulating effects of short- and long-term treatment with recombinant human growth hormone (rhGH) in growth-retarded children with chronic renal failure (CRF), 103 prepubertal children with CRF on conservative treatment (n = 74) or dialysis (n = 29) were treated with rhGH for up to 5 yr. rhGH treatment persistently increased standardized height (+ 1.6 SD scores) and predicted adult height (+7.7 cm, Tanner method) during the first 3 treatment years (P < 0.001 versus baseline), followed by percentile parallel growth during continued treatment. Both standardized height and predicted adult height were significantly more increased in conservatively treated than in dialyzed children (P < 0.001). Age, GFR, target height, and prestudy growth rate were identified as independent predictors of the response to rhGH treatment during the first and second treatment year. GFR and target height were positively correlated with the change in height SD score and the change in absolute or age-standardized height velocity. Age affected the growth response depending on which outcome measure was used: Although the first-year change in height SD score was inversely correlated with age, the change in absolute height velocity was independent of age, and the change in standardized height velocity was positively correlated with age. The growth response during the first treatment year positively predicted the long-term response. In conclusion, the short- and long-term growth response to rhGH treatment in prepubertal growth-retarded children with CRF is significantly affected by age, GFR, target height, and the pretreatment growth rate. Therefore, rhGH should be preferably started at a young age, and early in the course of CRF.

  9. PleurX drain use in the management of malignant ascites: safety, complications, long-term patency and factors predictive of success

    PubMed Central

    Tapping, C R; Ling, L; Razack, A

    2012-01-01

    Objectives The aim of this article was to assess the success, safety, complication profile and factors associated with long-term patency of tunnelled peritoneal drains (PleurX) in the treatment of refractory malignant ascites. Methods Over a 4-year period, 28 consecutive patients (32 drain insertions) with refractory malignant ascites were treated with a PleurX drain. The study group comprised 7 males and 21 females (mean age, 61 years). A combination of fluoroscopic and ultrasound guidance was used to insert 4 drains; the remaining 28 drains were inserted under ultrasound guidance alone. Patient history, biochemical profiles, pathological and procedural records and clinical follow-up until death were reviewed. Statistical analysis included multivariate logistic regression analysis and Kaplan–Meier curves (p<0.05 was considered significant). Results There was a 100% technical success rate for the insertion of the drain; there were no procedure-related deaths and no major complications. Only minor complications were reported: three (10%) immediate; three (10%) early; and two (7%) late. Factors significantly associated with these complications included current chemotherapy, low haemoglobin levels, low albumin levels, high white cell count and high c-reactive protein levels. The length of time the drains remained in situ, and therefore patent, ranged from 5 to 365 days (mean, 113 days). Out of the original 28 tunnelled drains, 24 (86%) remained in situ and functioning until the patients’ death. Four (14%) drains dislodged and a subsequent PleurX drain was inserted on the opposite side of the abdominal wall. These new drains remained patent until the patient’s death. The annual event rate was 0.45 events per year. A comorbid diagnosis of renal disease or chemotherapy was significantly related to a decreased length of patency. Conclusion The use of tunnelled peritoneal drains is safe and effective and we would advocate their use as a first-line approach in

  10. Infective endocarditis: determinants of long term outcome

    PubMed Central

    Netzer, R O M; Altwegg, S C; Zollinger, E; Täuber, M; Carrel, T; Seiler, C

    2002-01-01

    Objective: To evaluate predictors of long term prognosis in infective endocarditis. Design: Retrospective cohort study. Setting: Tertiary care centre. Patients: 212 consecutive patients with infective endocarditis between 1980 and 1995 Main outcome measures: Overall and cardiac mortality; event-free survival; and the following events: recurrence, need for late valve surgery, bleeding and embolic complications, cerebral dysfunction, congestive heart failure. Results: During a mean follow up period of 89 months (range 1–244 months), 56% of patients died. In 180 hospital survivors, overall and cardiac mortality amounted to 45% and 24%, respectively. By multivariate analysis, early surgical treatment, infection by streptococci, age < 55 years, absence of congestive heart failure, and > 6 symptoms or signs of endocarditis during active infection were predictive of improved overall long term survival. Independent determinants of event-free survival were infection by streptococci and age < 55 years. Event-free survival was 17% at the end of follow up both in medically–surgically treated patients and in medically treated patients. Conclusions: Long term survival following infective endocarditis is 50% after 10 years and is predicted by early surgical treatment, age < 55 years, lack of congestive heart failure, and the initial presence of more symptoms of endocarditis. PMID:12067947

  11. A practical method based on stress evaluation ({sigma}{sub d} criterion) to predict initiation of crack under creep and creep-fatigue conditions

    SciTech Connect

    Moulin, D.; Drubay, B.; Acker, D.; Laiarinandrasana, L.

    1995-11-01

    In some parts of primary circuit of fast breeder reactor, where the temperature is higher than 427 C, preservice inspection has revealed indications that were conservatively assumed to be sharp cracks. These pipes are made of 316 SPH material, an austenitic material close to 316L. This material is subjected to creep behavior at this temperature. Here, the behavior of defects like cracks in nuclear components operating at high temperature, where creep is significant, must be under control. There exists the need to have a practical method of analysis, which can be used by engineers, to calculate the time of initiation for defects existing at the start of life of nuclear components. This study presents the background, the development, the application, and results concerning validation work made for a simplified method named {sigma}{sub d} of prediction of initiation for nuclear structures made of 316L austenitic steel and operating at temperature where creep is significant. This method relies on the evaluation of real stress-strain history on a small distance d (d = 0.05 mm) close to the crack front and material characteristics (limiting stresses) that are available in nuclear codes like ASME Code cases or RCC-MR.

  12. Short and long-term prediction of recidivism using the youth level of service/case management inventory in a sample of serious young offenders.

    PubMed

    Olver, Mark E; Stockdale, Keira C; Wong, Stephen C P

    2012-08-01

    The present investigation examined the predictive accuracy of the Youth Level of Service/Case Management Inventory (YLS/CMI) for youth and adult recidivism in a Canadian sample of 167 youths (93 males, 74 females) charged with serious offenses who received psychological services from a community mental health outpatient clinic. Youths were followed for an average of 7 years in the community, and predictive accuracy was examined for several recidivism outcomes as a function of gender, ethnicity, and developmental age group. YLS/CMI total scores significantly predicted all recidivism categories in the overall sample (area under the curve values ranged from 0.66 to 0.77) although the instrument as a whole, and its criminogenic needs, demonstrated somewhat stronger and more consistent predictive accuracy for youth outcomes. The YLS/CMI also demonstrated significant predictive accuracy within demographic subgroups. The implications of these findings are discussed in terms of the use of risk-need assessment tools in providing clinical assessment, treatment, and case management services to diverse young offender groups.

  13. Decision tree model for predicting long-term outcomes in children with out-of-hospital cardiac arrest: a nationwide, population-based observational study

    PubMed Central

    2014-01-01

    Introduction At hospital arrival, early prognostication for children after out-of-hospital cardiac arrest (OHCA) might help clinicians formulate strategies, particularly in the emergency department. In this study, we aimed to develop a simple and generally applicable bedside tool for predicting outcomes in children after cardiac arrest. Methods We analyzed data of 5,379 children who had undergone OHCA. The data were extracted from a prospectively recorded, nationwide, Utstein-style Japanese database. The primary endpoint was survival with favorable neurological outcome (Cerebral Performance Category (CPC) scale categories 1 and 2) at 1 month after OHCA. We developed a decision tree prediction model by using data from a 2-year period (2008 to 2009, n = 3,693), and the data were validated using external data from 2010 (n = 1,686). Results Recursive partitioning analysis for 11 predictors in the development cohort indicated that the best single predictor for CPC 1 and 2 at 1 month was the prehospital return of spontaneous circulation (ROSC). The next predictor for children with prehospital ROSC was an initial shockable rhythm. For children without prehospital ROSC, the next best predictor was a witnessed arrest. Use of a simple decision tree prediction model permitted stratification into four outcome prediction groups: good (prehospital ROSC and initial shockable rhythm), moderately good (prehospital ROSC and initial nonshockable rhythm), poor (prehospital non-ROSC and witnessed arrest) and very poor (prehospital non-ROSC and unwitnessed arrest). By using this model, we identified patient groups ranging from 0.2% to 66.2% for 1-month CPC 1 and 2 probabilities. The validated decision tree prediction model demonstrated a sensitivity of 69.7% (95% confidence interval (CI) = 58.7% to 78.9%), a specificity of 95.2% (95% CI = 94.1% to 96.2%) and an area under the receiver operating characteristic curve of 0.88 (95% CI = 0.87 to 0.90) for predicting 1-month

  14. Using the Autism Detection in Early Childhood (ADEC) and Childhood Autism Rating Scales (CARS) to Predict Long Term Outcomes in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Nah, Yong-Hwee; Young, Robyn L.; Brewer, Neil

    2014-01-01

    This study evaluated the predictive validity of the Autism Detection in Early Childhood (ADEC; Young, Autism detection in early childhood: ADEC. Australian Council of Educational Research, Camberwell, VIC 2007) and a well-established screening tool, the Childhood Autism Rating Scale (CARS; Schopler et al. The childhood autism rating scale (CARS).…

  15. Predicting landscape-scale CO2 flux at a pasture and rice paddy with long-term hyperspectral canopy reflectance measurements

    NASA Astrophysics Data System (ADS)

    Matthes, J. H.; Knox, S. H.; Sturtevant, C.; Sonnentag, O.; Verfaillie, J.; Baldocchi, D.

    2015-08-01

    Measurements of hyperspectral canopy reflectance provide a detailed snapshot of information regarding canopy biochemistry, structure and physiology. In this study, we collected 5 years of repeated canopy hyperspectral reflectance measurements for a total of over 100 site visits within the flux footprints of two eddy covariance towers at a pasture and rice paddy in northern California. The vegetation at both sites exhibited dynamic phenology, with significant interannual variability in the timing of seasonal patterns that propagated into interannual variability in measured hyperspectral reflectance. We used partial least-squares regression (PLSR) modeling to leverage the information contained within the entire canopy reflectance spectra (400-900 nm) in order to investigate questions regarding the connection between measured hyperspectral reflectance and landscape-scale fluxes of net ecosystem exchange (NEE) and gross primary productivity (GPP) across multiple timescales, from instantaneous flux to monthly integrated flux. With the PLSR models developed from this large data set we achieved a high level of predictability for both NEE and GPP flux in these two ecosystems, where the R2 of prediction with an independent validation data set ranged from 0.24 to 0.69. The PLSR models achieved the highest skill at predicting the integrated GPP flux for the week prior to the hyperspectral canopy reflectance collection, whereas the NEE flux often achieved the same high predictive power at daily to monthly integrated flux timescales. The high level of predictability achieved by PLSR in this study demonstrated the potential for using repeated hyperspectral canopy reflectance measurements to help partition NEE into its component fluxes, GPP and ecosystem respiration, and for using quasi-continuous hyperspectral reflectance measurements to model regional carbon flux in future analyses.

  16. Predicting landscape-scale CO2 flux at a pasture and rice paddy with long-term hyperspectral canopy reflectance measurements

    NASA Astrophysics Data System (ADS)

    Matthes, J. H.; Knox, S. H.; Sturtevant, C.; Sonnentag, O.; Verfaillie, J.; Baldocchi, D.

    2015-03-01

    Measurements of hyperspectral canopy reflectance provide a detailed snapshot of information regarding canopy biochemistry, structure and physiology. In this study, we collected five years of repeated canopy hyperspectral reflectance measurements for a total of over 100 site visits within the flux footprints of two eddy covariance towers at a pasture and rice paddy in Northern California. The vegetation at both sites exhibited dynamic phenology, with significant inter-annual variability in the timing of seasonal patterns that propagated into inter-annual variability in measured hyperspectral reflectance. We used partial least-squares regression (PLSR) modeling to leverage the information contained within the entire continuous canopy reflectance spectra (400-900 nm) in order to investigate questions regarding the connection between measured hyperspectral reflectance and landscape-scale fluxes of net ecosystem exchange (NEE) and gross primary productivity (GPP) across multiple timescales, from instantaneous flux to monthly-integrated flux. With the PLSR models developed from this large dataset we achieved a high level of predictability for both NEE and GPP flux in these two ecosystems, where the R2 of prediction with an independent validation dataset ranged from 0.24 to 0.69. The PLSR models achieved the highest skill at predicting the integrated GPP flux for the week prior to the hyperspectral canopy reflectance collection, whereas the NEE flux often achieved the same high predictive power at the daily- through monthly-integrated flux timescales. The high level of predictability achieved by PLSR regression in this study demonstrated the potential for using repeated hyperspectral canopy reflectance measurements to help partition NEE measurements into its component fluxes, GPP and ecosystem respiration, and for using continuous hyperspectral reflectance measurements to model regional carbon flux in future analyses.

  17. Predicting Clinical Outcomes Using Baseline and Follow-up Laboratory Data From The Hepatitis C Long-term Treatment Against Cirrhosis Trial

    PubMed Central

    Ghany, Marc G.; Kim, Hae-Young; Stoddard, Anne; Wright, Elizabeth C.; Seeff, Leonard B.; Lok, Anna S.F.

    2013-01-01

    Background and Aims Predicting clinical outcomes in patients with chronic hepatitis C is challenging. We used the HALT-C Trial database to develop two models, using baseline values of routinely available laboratory tests together with changes in these values during follow-up to predict clinical decompensation and liver-related death/liver transplant in patients with advanced hepatitis C. Methods Patients randomized to no treatment and who had ≥2 year follow-up without a clinical outcome were included in the analysis. Four variables (platelet count, AST/ALT ratio, total bilirubin and albumin) with three categories of change (stable, mild or severe) over two years were analyzed. Cumulative incidence of clinical outcome was determined by Kaplan-Meier analysis and Cox regression was used to evaluate predictors of clinical outcome. Results 470 patients with 60 events were used to develop models to predict clinical decompensation. Baseline values of all four variables were predictive of decompensation. There was a general trend of increasing outcomes with more marked worsening of laboratory values over 2 years, particularly for patients with abnormal baseline values. A model that included baseline platelet count, AST/ALT ratio, bilirubin and severe worsening of platelet count, bilirubin and albumin was the best predictor of clinical decompensation. 483 patients with 79 events were used to evaluate predictors of liver-related death or liver transplant. A model that included baseline platelet count and albumin as well as severe worsening of AST/ALT ratio and albumin was the best predictor of liver-related outcomes. Conclusion Both the baseline value and the rapidity in change of the value of routine laboratory variables were shown to be important in predicting clinical outcomes in patients with advanced chronic hepatitis C. PMID:22045670

  18. Research Opportunities in Corrosion Science for Long-Term Prediction of Materials Performance: A Report of the DOE Workshop on “Corrosion Issues of Relevance to the Yucca Mountain Waste Repository”.

    SciTech Connect

    Payer, Joe H.; Scully, John R.

    2003-07-29

    The report summarizes the findings of a U.S. Department of Energy workshop on “Corrosion Issues of Relevance to the Yucca Mountain Waste Repository”. The workshop was held on July 29-30, 2003 in Bethesda, MD, and was co-sponsored by the Office of Basic Energy Sciences and Office of Civilian Radioactive Waste Management. The workshop focus was corrosion science relevant to long-term prediction of materials performance in hostile environments, with special focus on relevance to the permanent disposal of nuclear waste at the Yucca Mountain Repository. The culmination of the workshop is this report that identifies both generic and Yucca Mountain Project-specific research opportunities in basic and applied topic areas. The research opportunities would be realized well after the U.S. Nuclear Regulatory Commission’s initial construction-authorization licensing process. At the workshop, twenty-three invited scientists deliberated on basic and applied science opportunities in corrosion science relevant to long-term prediction of damage accumulation by corrosive processes that affect materials performance.

  19. Mechanistic Prediction of the Effect of Microstructural Coarsening on Creep Response of SnAgCu Solder Joints

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Chauhan, P.; Osterman, M.; Dasgupta, A.; Pecht, M.

    2016-07-01

    Mechanistic microstructural models have been developed to capture the effect of isothermal aging on time dependent viscoplastic response of Sn3.0Ag0.5Cu (SAC305) solders. SnAgCu (SAC) solders undergo continuous microstructural coarsening during both storage and service because of their high homologous temperature. The microstructures of these low melting point alloys continuously evolve during service. This results in evolution of creep properties of the joint over time, thereby influencing the long term reliability of microelectronic packages. It is well documented that isothermal aging degrades the creep resistance of SAC solder. SAC305 alloy is aged for (24-1000) h at (25-100)°C (~0.6-0.8 × T melt). Cross-sectioning and image processing techniques were used to periodically quantify the effect of isothermal aging on phase coarsening and evolution. The parameters monitored during isothermal aging include size, area fraction, and inter-particle spacing of nanoscale Ag3Sn intermetallic compounds (IMCs) and the volume fraction of micronscale Cu6Sn5 IMCs, as well as the area fraction of pure tin dendrites. Effects of microstructural evolution on secondary creep constitutive response of SAC305 solder joints were then modeled using a mechanistic multiscale creep model. The mechanistic phenomena modeled include: (1) dispersion strengthening by coarsened nanoscale Ag3Sn IMCs in the eutectic phase; and (2) load sharing between pro-eutectic Sn dendrites and the surrounding coarsened eutectic Sn-Ag phase and microscale Cu6Sn5 IMCs. The coarse-grained polycrystalline Sn microstructure in SAC305 solder was not captured in the above model because isothermal aging does not cause any significant change in the initial grain size and orientation of SAC305 solder joints. The above mechanistic model can successfully capture the drop in creep resistance due to the influence of isothermal aging on SAC305 single crystals. Contribution of grain boundary sliding to the creep strain of

  20. fMRI reactivity to high-calorie food pictures predicts short- and long-term outcome in a weight-loss program.

    PubMed

    Murdaugh, Donna L; Cox, James E; Cook, Edwin W; Weller, Rosalyn E

    2012-02-01

    Behavioral studies have suggested that food cues have stronger motivating effects in obese than in normal-weight individuals, which may be a risk factor underlying obesity. Previous cross-sectional neuroimaging studies have suggested that this difference is mediated by increased reactivity to food cues in parts of the reward system in obese individuals. To date, however, only a few prospective neuroimaging studies have been conducted to examine whether individual differences in brain activation elicited by food cues can predict differences in weight change. We used functional magnetic resonance imaging (fMRI) to investigate activation in reward-system as well as other brain regions in response to viewing high-calorie food vs. control pictures in 25 obese individuals before and after a 12-week psychosocial weight-loss treatment and at 9-mo follow-up. In those obese individuals who were least successful in losing weight during the treatment, we found greater pre-treatment activation to high-calorie food vs. control pictures in brain regions implicated in reward-system processes, such as the nucleus accumbens, anterior cingulate, and insula. We found similar correlations with weight loss in brain regions implicated by other studies in vision and attention, such as superior occipital cortex, inferior and superior parietal lobule, and prefrontal cortex. Furthermore, less successful weight maintenance at 9-mo follow-up was predicted by greater post-treatment activation in such brain regions as insula, ventral tegmental area, putamen, and fusiform gyrus. In summary, we found that greater activation in brain regions mediating motivational and attentional salience of food cues in obese individuals at the start of a weight-loss program was predictive of less success in the program and that such activation following the program predicted poorer weight control over a 9-mo follow-up period.

  1. Human eastern equine encephalitis in Massachusetts: predictive indicators from mosquitoes collected at 10 long-term trap sites, 1979-2004.

    PubMed

    Hachiya, Masahiko; Osborne, Matthew; Stinson, Cynthia; Werner, Barbara G

    2007-02-01

    Human eastern equine encephalitis (EEE) is a life-threatening mosquito-borne disease. To determine whether mosquito abundance and EEE virus infection rates are associated with human EEE disease, we evaluated retrospectively a total of 592,637 mosquitoes and onset dates for 20 confirmed human cases over 26 years in Massachusetts. Annual Culiseta melanura populations at 10 defined sites decreased over the study period (P = 0.002). Weekly infection rates and number of infected Culiseta melanura captured per trap night were positively associated EEE cases (P < 0.023 and P < 0.001, respectively), whereas abundance was not (P = 0.077). The infection rate for Culiseta melanura of 0.39 per 1,000 tested mosquitoes identified human cases with a sensitivity of 0.87, a specificity of 0.82, a positive predictive value of 0.14, and a negative predictive value of 0.995. Timely mosquito testing and infection rate calculation are critical for disease risk estimation and outbreak control efforts.

  2. The predictive validity of the Two-Tiered Violence Risk Estimates Scale (TTV) in a long-term follow-up of violent offenders.

    PubMed

    Churcher, Frances P; Mills, Jeremy F; Forth, Adelle E

    2016-08-01

    Over the past few decades many structured risk appraisal measures have been created to respond to this need. The Two-Tiered Violence Risk Estimates Scale (TTV) is a measure designed to integrate both an actuarial estimate of violence risk with critical risk management indicators. The current study examined interrater reliability and the predictive validity of the TTV in a sample of violent offenders (n = 120) over an average follow-up period of 17.75 years. The TTV was retrospectively scored and compared with the Violence Risk Appraisal Guide (VRAG), the Statistical Information of Recidivism Scale-Revised (SIR-R1), and the Psychopathy Checklist-Revised (PCL-R). Approximately 53% of the sample reoffended violently, with an overall recidivism rate of 74%. Although the VRAG was the strongest predictor of violent recidivism in the sample, the Actuarial Risk Estimates (ARE) scale of the TTV produced a small, significant effect. The Risk Management Indicators (RMI) produced nonsignificant area under the curve (AUC) values for all recidivism outcomes. Comparisons between measures using AUC values and Cox regression showed that there were no statistical differences in predictive validity. The results of this research will be used to inform the validation and reliability literature on the TTV, and will contribute to the overall risk assessment literature. (PsycINFO Database Record

  3. Developing a Long-Term Forest Gap Model to Predict the Behavior of California Pines, Oaks, and Cedars Under Climate Change and Other Disturbance Scenarios

    NASA Astrophysics Data System (ADS)

    Davis, S. L.; Moran, E.

    2015-12-01

    Many predictions about how trees will respond to climate change have been made, but these often rely on extrapolating into the future one of two extremes: purely correlative factors like climate, or purely physiological factors unique to a particular species or plant functional group. We are working towards a model that combines both phenotypic and genotypic traits to better predict responses of trees to climate change. We have worked to parameterize a neighborhood dynamics, individual tree forest-gap model called SORTIE-ND, using open data from both the USDA Forest Service Forest Inventory & Analysis (FIA) datasets in California and 30-yr old permanent plots established by the USGS. We generated individual species factors including stage-specific mortality and growth rates, and species-specific allometric equations for ten species, including Abies concolor, A. magnifica, Calocedrus decurrens, Pinus contorta, P. jeffreyi, P. lambertiana, P. monticola, P. ponderosa, and the two hardwoods Quercus chrysolepis and Q. kelloggii. During this process, we also developed two R packages to aid in parameter development for SORTIE-ND in other ecological systems. MakeMyForests is an R package that parses FIA datasets and calculates parameters based on the state averages of growth, light, and allometric parameters. disperseR is an R package that uses extensive plot data, with individual tree, sapling, and seedling measurements, to calculate finely tuned mortality and growth parameters for SORTIE-ND. Both are freely available on GitHub, and future updates will be available on CRAN. To validate the model, we withheld several plots from the 30-yr USGS data while calculating parameters. We tested for differences between the actual withheld data and the simulated forest data, in basal area, seedling density, seed dispersal, and species composition. The similarity of our model to the real system suggests that the model parameters we generated with our R packages accurately represent

  4. Performance considerations in long-term spaceflight

    NASA Technical Reports Server (NTRS)

    Akins, F. R.

    1979-01-01

    Maintenance of skilled performance during extended space flight is of critical importance to both the health and safety of crew members and to the overall success of mission goals. An examination of long term effects and performance requirements is therefore a factor of immense importance to the planning of future missions. Factors that were investigated include: definition of performance categories to be investigated; methods for assessing and predicting performance levels; in-flight factors which can affect performance; and factors pertinent to the maintenance of skilled performance.

  5. A long-term three dimensional liver co-culture system for improved prediction of clinically relevant drug-induced hepatotoxicity

    SciTech Connect

    Kostadinova, Radina; Boess, Franziska; Suter, Laura; Weiser, Thomas; Singer, Thomas; Roth, Adrian

    2013-04-01

    Drug-induced liver injury (DILI) is the major cause for liver failure and post-marketing drug withdrawals. Due to species-specific differences in hepatocellular function, animal experiments to assess potential liabilities of drug candidates can predict hepatotoxicity in humans only to a certain extent. In addition to animal experimentation, primary hepatocytes from rat or human are widely used for pre-clinical safety assessment. However, as many toxic responses in vivo are mediated by a complex interplay among different cell types and often require chronic drug exposures, the predictive performance of hepatocytes is very limited. Here, we established and characterized human and rat in vitro three-dimensional (3D) liver co-culture systems containing primary parenchymal and non-parenchymal hepatic cells. Our data demonstrate that cells cultured on a 3D scaffold have a preserved composition of hepatocytes, stellate, Kupffer and endothelial cells and maintain liver function for up to 3 months, as measured by the production of albumin, fibrinogen, transferrin and urea. Additionally, 3D liver co-cultures maintain cytochrome P450 inducibility, form bile canaliculi-like structures and respond to inflammatory stimuli. Upon incubation with selected hepatotoxicants including drugs which have been shown to induce idiosyncratic toxicity, we demonstrated that this model better detected in vivo drug-induced toxicity, including species-specific drug effects, when compared to monolayer hepatocyte cultures. In conclusion, our results underline the importance of more complex and long lasting in vitro cell culture models that contain all liver cell types and allow repeated drug-treatments for detection of in vivo-relevant adverse drug effects. - Highlights: ► 3D liver co-cultures maintain liver specific functions for up to three months. ► Activities of Cytochrome P450s remain drug- inducible accross three months. ► 3D liver co-cultures recapitulate drug-induced liver toxicity

  6. The Prediction of Long-Term Coating Performance from Short-Term Electrochemical Data. Part 2; Comparison of Electrochemical Data to Field Exposure Results for Coatings on Steel

    NASA Technical Reports Server (NTRS)

    Contu, F.; Taylor, S. R.; Calle, L. M.; Hintze, P. E.; Curran, J. P.; Li, W.

    2009-01-01

    The pace of coatings development is limited by the time required to assess their corrosion protection properties. This study takes a step f orward from Part I in that it correlates the corrosion performance of organic coatings assessed by a series of short-term electrochemical measurement with 18-month beachside exposure results of duplicate pan els. A series of 19 coating systems on A36 steel substrates were test ed in a completely blind study using the damage tolerance test (DTT). In the DTT, a through-film pinhole defect is created, and the electro chemical characteristics of the defect are then monitored over the ne xt 4 to 7 days while immersed in 0.SM NaCl. The open circuit potentia l, anodic potentiostatic polarization tests and electrochemical imped ance spectroscopy were used to study the corrosion behavior of the co ating systems. The beachside exposure tests were conducted at the Ken nedy Space Center according to ASTM D610-01. It was found that for 79 % of the coatings systems examined, the 18 month beachside exposure r esults could be predicted by two independent laboratory tests obtained within 7 days.

  7. Trends from the Long-term Data Record and Models: What Do They Tell Us About our Ability to Predict Ozone Recovery?

    NASA Technical Reports Server (NTRS)

    Strahan, Susan; Stolarski, Richard; Douglass, Anne; Steenrod, Stephen

    2005-01-01

    Our industrial society has performed an experiment on the stratospheric ozone layer over the last several decades. The initial part of this experiment was the rapidly increasing release of halogen-containing compounds that carry chlorine and bromine to the stratosphere where they can cause a loss of ozone. The present part of this experiment is the implementation of the Montreal Protocol, which has led to a leveling off of these halogen compounds and the beginning of their slow removal from the atmosphere. The observation and attribution of ozone response to the halogens has been a particularly important and difficult task because of the impact of solar cycle uv variation, two major volcanic eruptions (El Chichon and Pinatubo), and interannual dynamic variability of the stratosphere. We have run 3 different simulations of the chemistry and transport of ozone and the minor constituents that affect ozone to help evaluate our understanding of the causes of ozone change and to assess our ability to predict ozone recovery with the removal of halogens from the stratosphere. One simulation, using the Goddard chemical transport model (CTM), had interannual variability in the dynamics for the entire 50 years of simulation, which included the past 3 decades (1974-2004) and the next 2 decades to 2022. The other two simulations used the Global Modeling Initiative (GMI) CTM with no dynamical variability: one used a the winds and temperatures from a repeating warm Arctic winter and the other used a repeating cold Arctic winter. All simulations included the effects of aerosol surfaces from volcanic eruptions on chemical reactions as well as the variation in UV over the 11-year solar cycle.

  8. Cortisol response to an experimental stress paradigm prospectively predicts long-term distress and resilience trajectories in response to active police service.

    PubMed

    Galatzer-Levy, Isaac R; Steenkamp, Maria M; Brown, Adam D; Qian, Meng; Inslicht, Sabra; Henn-Haase, Clare; Otte, Christian; Yehuda, Rachel; Neylan, Thomas C; Marmar, Charles R

    2014-09-01

    Heterogeneity in glucocorticoid response to experimental stress conditions has shown to differentiate individuals with healthy from maladaptive real-life stress responses in a number of distinct domains. However, it is not known if this heterogeneity influences the risk for developing stress related disorders or if it is a biological consequence of the stress response itself. Determining if glucocorticoid response to stress induction prospectively predicts psychological vulnerability to significant real life stressors can adjudicate this issue. To test this relationship, salivary cortisol as well as catecholamine responses to a laboratory stressor during academy training were examined as predictors of empirically identified distress trajectories through the subsequent 4 years of active duty among urban police officers routinely exposed to potentially traumatic events and routine life stressors (N = 234). During training, officers were exposed to a video vignette of police officers exposed to real-life trauma. Changes in salivary 3-methoxy-4-hydroxyphenylglycol (MHPG) and cortisol in response to this video challenge were examined as predictors of trajectory membership while controlling for age, gender, and baseline neuroendocrine levels. Officers who followed trajectories of resilience and recovery over 4 years mounted significant increases in cortisol in response to the experimental stressor, while those following a trajectory of chronic increasing distress had no significant cortisol change in response to the challenge. MHPG responses were not associated with distress trajectories. Cortisol response prospectively differentiated trajectories of distress response suggesting that a blunted cortisol response to a laboratory stressor is a risk factor for later vulnerability to distress following significant life stressors.

  9. Data-driven modeling of radionuclide inventory at the Savannah River Site F-area seepage basins and implications for long-term behavior predictions

    NASA Astrophysics Data System (ADS)

    Wiedmer, A.; Hunt, J. R.; Agarwal, D.; Faybishenko, B.

    2012-12-01

    The availability of data is a major constraint in the development of a conceptual model and predictions of physical and chemical processes impacting contaminant behavior in the subsurface. For example, a wealth of data has been collected over the past 60 years from a network of several hundred groundwater wells and surface water monitoring stations at the Department of Energy (DOE) Savannah River Site (SRS). The data were collected during and following the release of low-level liquid waste into seepage basins, as well as during the application of various groundwater remediation techniques. The result is a dataset of over 350,000 measurements. To analyze these data, we used a new data management system being developed as part of the DOE initiative on Advanced Simulation Capability for Environmental Management (ASCEM). This system was developed for easier access, management, visualization, and exploration of large amounts of heterogeneous data. Using this system, we developed a data-driven model for the evaluation of a mass balance and the inventory of the F-Area seepage basins and the groundwater plume. Process operations at the F-area led to the discharge of more than 4×109 L of low-level liquid radioactive waste containing tritium, uranium and fission products into the seepage basins. Between 1953 and 1989, 8.6×104 Ci (corrected for evaporation and decay to 1989) of tritium was released into the basins according to operational data. Starting in the 1960s, SRS monitored radioactivity in the Fourmile Branch (FMB) located downgradient of the basins. Through 1989 around 43% of the total release was detected in FMB, leaving an estimated inventory of 57% in the subsurface as of 1989. This model was used to assess t he sources of uncertainty in the mass balance calculations. The results of calculations of the tritium inventory in groundwater were compared with those from monitoring data prior to remediation, as well as were used to estimate the time needed to achieve

  10. Long-term prediction of three-dimensional bone architecture in simulations of pre-, peri- and post-menopausal microstructural bone remodeling.

    PubMed

    Müller, Ralph

    2005-03-01

    The mechanical behavior of trabecular bone depends on the internal bone structure. It is generally accepted now that the trabecular bone structure is a result of a load adaptive bone remodeling. The mathematical laws that relate bone remodeling to the local state of stress and strain, however, are still under investigation. The aim of this project was to investigate if changes in the trabecular architecture as observed with age-related bone loss and osteoporosis can be predicted from a computer model that simulates bone resorption after hormone depletion based on realistic models of trabecular microstructure using micro-computed tomography (muCT). A compact desktop muCT providing a nominal isotropic resolution of 14 mum was used to measure two groups of seven trabecular bone specimens from pre-menopausal and post-menopausal women respectively. A novel algorithm was developed to simulate age-related bone loss for the specimens in the first group. The algorithm, also referred to as simulated bone atrophy (SIBA), describes a truly three-dimensional approach and is based directly on cellular bone remodeling with an underlying realistic time frame. Bone resorption is controlled by osteoclastic penetration depth and bone formation is governed by the efficiency level of the osteoblasts. The simulation itself describes an iterative process with a cellular remodeling cycle of 197 days. Activation frequency is controllable and can be adjusted for the different phases of pre-, peri- and post-menopause. For our simulations, osteoblastic and osteoclastic activities were in balance until the onset of menopause, set to be at the age of 50 years. In that period, the structure remained almost constant. After the onset of menopause an imbalance in the cell activities was modeled resulting in a net bone loss. The doubling of the activation frequency in the peri-menopausal phase caused a pronounced loss. Using advanced animation tools and quantitative bone morphometry, the changes in

  11. Interaction between plasma fetuin-A and free fatty acids predicts changes in insulin sensitivity in response to long-term exercise.

    PubMed

    Lee, Sindre; Norheim, Frode; Gulseth, Hanne L; Langleite, Torgrim M; Kolnes, Kristoffer J; Tangen, Daniel S; Stadheim, Hans K; Gilfillan, Gregor D; Holen, Torgeir; Birkeland, Kåre I; Jensen, Jørgen; Drevon, Christian A

    2017-03-01

    The hepatokine fetuin-A can together with free fatty acids (FFAs) enhance adipose tissue (AT) inflammation and insulin resistance via toll-like receptor 4 (TLR4). Although some of the health benefits of exercise can be explained by altered release of myokines from the skeletal muscle, it is not well documented if some of the beneficial effects of exercise can be explained by altered secretion of hepatokines. The aim of this study was to examine the effect of interaction between fetuin-A and FFAs on insulin sensitivity after physical exercise. In this study, 26 sedentary men who underwent 12 weeks of combined endurance and strength exercise were included. Insulin sensitivity was measured using euglycemic-hyperinsulinemic clamp, and AT insulin resistance was indicated by the product of fasting plasma concentration of FFAs and insulin. Blood samples and biopsies from skeletal muscle and subcutaneous AT were collected. Several phenotypic markers were measured, and mRNA sequencing was performed on the biopsies. AT macrophages were analyzed based on mRNA markers. The intervention improved hepatic parameters, reduced plasma fetuin-A concentration (~11%, P < 0.01), slightly changed FFAs concentration, and improved glucose infusion rate (GIR) (~33%, P < 0.01) across all participants. The change in circulating fetuin-A and FFAs interacted to predict some of the change in GIR (β = -42.16, P = 0.030), AT insulin resistance (β = 0.579, P = 0.003), gene expression related to TLR-signaling in AT and AT macrophage mRNA (β = 94.10, P = 0.034) after exercise. We observed no interaction effects between FFAs concentrations and leptin and adiponectin on insulin sensitivity, or any interaction effects between Fetuin-A and FFAs concentrations on skeletal muscle TLR-signaling. The relationship between FFAs levels and insulin sensitivity seemed to be specific for fetuin-A and the AT Some of the beneficial effects of exercise on insulin sensitivity may be explained by

  12. Reducing long-term reservoir performance uncertainty

    SciTech Connect

    Lippmann, M.J.

    1988-04-01

    Reservoir performance is one of the key issues that have to be addressed before going ahead with the development of a geothermal field. In order to select the type and size of the power plant and design other surface installations, it is necessary to know the characteristics of the production wells and of the produced fluids, and to predict the changes over a 10--30 year period. This is not a straightforward task, as in most cases the calculations have to be made on the basis of data collected before significant fluid volumes have been extracted from the reservoir. The paper describes the methodology used in predicting the long-term performance of hydrothermal systems, as well as DOE/GTD-sponsored research aimed at reducing the uncertainties associated with these predictions. 27 refs., 1 fig.

  13. Formation of laves phase in a refractory austenitic steel due to long-term heating

    NASA Astrophysics Data System (ADS)

    Tarasenko, L. V.; Shal'kevich, A. B.

    2011-07-01

    Steels of the Fe - Cr - Ni -Mo - Nb - Al - C system are studied by methods of phase physicochemical analysis and electron microscopy with the aim to determine the causes of changes in mechanical properties after long-term heating at a temperature of 600 - 700°C. Grain-boundary formation of particles of a Laves phase is shown to cause decrease in the impact toughness and transformation of particles of γ'-phase under conditions of creep. The effect of alloying elements on the chemical composition of the multicomponent Laves phase is studied depending on the temperatures of hardening, aging, and subsequent heating. Concentration correspondence between the chemical composition of the austenite and the intermetallic tcp phase formed in aging is discovered. A computational scheme for predicting the possibility of formation of Laves phases in multicomponent alloys is suggested.

  14. Asthma Medicines: Long-Term Control

    MedlinePlus

    ... Size Email Print Share Asthma Medicines: Long-term Control Page Content Article Body Corticosteroids Synthetic versions of ... form, they are used exclusively for long-term control; they are not very effective for acute symptoms. ...

  15. CYP2B6*6 and CYP2B6*18 Predict Long-Term Efavirenz Exposure Measured in Hair Samples in HIV-Positive South African Women.

    PubMed

    Röhrich, Carola R; Drögemöller, Britt I; Ikediobi, Ogechi; van der Merwe, Lize; Grobbelaar, Nelis; Wright, Galen E B; McGregor, Nathaniel; Warnich, Louise

    2016-06-01

    Long-term exposure to efavirenz (EFV) measured in hair samples may predict response to antiretroviral treatment (ART). Polymorphisms in CYP2B6 are known to alter EFV levels. The aim of this study was to assess the relationship between CYP2B6 genotype, EFV levels measured in hair, and virological outcomes on ART in a real-world setting. We measured EFV levels in hair from HIV-positive South African females who had been receiving EFV-based treatment for at least 3 months from the South African Black (SAB) (n = 81) and Cape Mixed Ancestry (CMA) (n = 53) populations. Common genetic variation in CYP2B6 was determined in 15 individuals from each population using bidirectional Sanger sequencing. Prioritized variants (n = 16) were subsequently genotyped in the entire patient cohort (n = 134). The predictive value of EFV levels in hair and selected variants in CYP2B6 on virological treatment outcomes was assessed. Previously described alleles (CYP2B6*2, CYP2B6*5, CYP2B6*6, CYP2B6*17, and CYP2B6*18), as well as two novel alleles (CYP2B6*31 and CYP2B6*32), were detected in this study. Compared to noncarriers, individuals homozygous for CYP2B6*6 had ∼109% increased EFV levels in hair (p = .016) and CYP2B6*18 heterozygotes demonstrated 82% higher EFV hair levels (p = .0006). This study confirmed that alleles affecting CYP2B6 metabolism and subsequent EFV exposure are present at significant frequencies in both the SAB and CMA populations. Furthermore, this study demonstrated that the use of hair samples for testing EFV concentrations may be a useful tool in determining long-term drug exposure in resource-limited countries.

  16. Long Term Surface Salinity Measurements

    NASA Technical Reports Server (NTRS)

    Schmitt, Raymond W.; Brown, Neil L.

    2005-01-01

    Our long-term goal is to establish a reliable system for monitoring surface salinity around the global ocean. Salinity is a strong indicator of the freshwater cycle and has a great influence on upper ocean stratification. Global salinity measurements have potential to improve climate forecasts if an observation system can be developed. This project is developing a new internal field conductivity cell that can be protected from biological fouling for two years. Combined with a temperature sensor, this foul-proof cell can be deployed widely on surface drifters. A reliable in-situ network of surface salinity sensors will be an important adjunct to the salinity sensing satellite AQUARIUS to be deployed by NASA in 2009. A new internal-field conductivity cell has been developed by N Brown, along with new electronics. This sensor system has been combined with a temperature sensor to make a conductivity - temperature (UT) sensor suitable for deployment on drifters. The basic sensor concepts have been proven on a high resolution CTD. A simpler (lower cost) circuit has been built for this application. A protection mechanism for the conductivity cell that includes antifouling protection has also been designed and built. Mr. A.Walsh of our commercial partner E-Paint has designed and delivered time-release formulations of antifoulants for our application. Mr. G. Williams of partner Clearwater Instrumentation advised on power and communication issues and supplied surface drifters for testing.

  17. AB055. Long term NIV

    PubMed Central

    Siopi, Dimitra

    2016-01-01

    During the last decades, non-invasive mechanical ventilation has evolved into one of the most evidence-based areas of respiratory medicine, with many indications in acute or chronic respiratory failure. From the first application of negative pressure models during poliomyelitis epidemics to the new sophisticated positive pressure models, and the development of the “intelligent ventilators”, there has been a long time course. Undoubtedly the spur was given by better understanding of respiratory physiology during sleep and the shift of healthcare towards a chronic base. Novel randomized controlled trials (RCTs) established the use of NIV in acute respiratory failure due to exacerbations of COPD, as well as acute pulmonary edema and weaning from invasive mechanical ventilation. Long-term NIV has been used in neuromuscular diseases for many decades, first in Duchenne muscular dystrophy, and then spreading to other disorders of this category, increasing survival in inherited neuromuscular diseases. NIV should be initiated early in the course of the disease, when symptomatic nocturnal hypoventilation is detected. Combined with cough augmentation (physiotherapy, insufflation-exsufflation devices) and percutaneous gastrostomy feeding, it can delay tracheostomy and invasive ventilation. In ALS patients NIV improves the quality of life and increases survival, especially when there is no bulbar involvement. The right time to initiate ventilation in this group of patients is not well established since it is difficult to detect signs and symptom of respiratory impairment. Patients seem to benefit from an early application of NIV, and their personal decisions should always be considered before any intervention. In patients with chest wall disorders NIV—despite the fact that RCTs are lacking—has proved its value in many uncontrolled trials and numerous reports. It seems to improve the work of breathing, sleep architecture, nocturnal and daytime arterial blood gases. The

  18. Long-Term Planning in Higher Education.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization, Bangkok (Thailand). Principal Regional Office for Asia and the Pacific.

    This report presents the concepts and issues discussed at a Regional Symposium on Long-term Planning in Higher Education held in Dhaka, Bangladesh, September 21-30, 1986. Chapter 1 explores some fundamental issues about the rationale for the objectives of long-term planning. It defines long-term planning in higher education, considers its…

  19. Long Term TOA - M Data and Information

    Atmospheric Science Data Center

    2015-06-30

    A Long-Term TOA and Constrained Surface Radiation Budget Project A Long-Term TOA and Constrained Surface Readiation Budget Dataset Using Merged CERES, ... and apply the knowledge to existing data to develop long-term (nearly 30 years) consistent and calibrated data product (TOA irradiances ...

  20. Sleep facilitates long-term face adaptation.

    PubMed

    Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

    2013-10-22

    Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as 'storage'. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation--which are usually not considered to play a relevant role in mnemonic processes--with learning and memory, and at the same time reveal a new function of sleep in cognition.

  1. Sleep facilitates long-term face adaptation

    PubMed Central

    Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

    2013-01-01

    Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as ‘storage’. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation—which are usually not considered to play a relevant role in mnemonic processes—with learning and memory, and at the same time reveal a new function of sleep in cognition. PMID:23986109

  2. The neuronal response at extended timescales: long-term correlations without long-term memory

    PubMed Central

    Soudry, Daniel; Meir, Ron

    2014-01-01

    Long term temporal correlations frequently appear at many levels of neural activity. We show that when such correlations appear in isolated neurons, they indicate the existence of slow underlying processes and lead to explicit conditions on the dynamics of these processes. Moreover, although these slow processes can potentially store information for long times, we demonstrate that this does not imply that the neuron possesses a long memory of its input, even if these processes are bidirectionally coupled with neuronal response. We derive these results for a broad class of biophysical neuron models, and then fit a specific model to recent experiments. The model reproduces the experimental results, exhibiting long term (days-long) correlations due to the interaction between slow variables and internal fluctuations. However, its memory of the input decays on a timescale of minutes. We suggest experiments to test these predictions directly. PMID:24744724

  3. Comprehensive Creep and Thermophysical Performance of Refractory Materials

    SciTech Connect

    Ferber, M.K.; Wereszczak, A.; Hemrick, J.A.

    2006-06-29

    Furnace designers and refractory engineers recognize that optimized furnace superstructure design and refractory selection are needed as glass production furnaces are continually striving toward greater output and efficiencies. Harsher operating conditions test refractories to the limit, while changing production technology (such as the conversion to oxy-fuel from traditional air-fuel firing) can alter the way the materials perform [1-3]. Refractories for both oxy- and air-fuel fired furnace superstructures (see Fig. 1) are subjected to high temperatures that may cause them to creep excessively or subside during service if the refractory material is not creep resistant, or if it is subjected to high stress, or both. Furnace designers can ensure that superstructure structural integrity is maintained if the creep behavior of the refractory material is well understood and well represented by appropriate engineering creep models. Several issues limit the abilities of furnace designers to (1) choose the optimum refractory for their applications, (2) optimize the engineering design, or (3) predict the service mechanical integrity of their furnace superstructures. Published engineering creep data are essentially nonexistent for almost all commercially available refractories used for glass furnace superstructures. The limited data that do exist are supplied by the various refractory suppliers. Unfortunately, the suppliers generally have different ways of conducting their mechanical testing, and they interpret and report their data differently. This inconsistency makes it hard for furnace designers to draw fair comparisons between competing grades of candidate refractories. Furthermore, the refractory suppliers' data are often not available in a form that can be readily used for furnace design or for the prediction and design of long-term structural integrity of furnace superstructures. As a consequence, the U.S. Department of Energy (DOE) Industrial Technology Program (ITP

  4. Comparison of measured temperatures, thermal stresses and creep residues with predictions on a built-up titanium structure

    NASA Technical Reports Server (NTRS)

    Jenkins, Jerald M.

    1987-01-01

    Temperature, thermal stresses, and residual creep stresses were studied by comparing laboratory values measured on a built-up titanium structure with values calculated from finite-element models. Several such models were used to examine the relationship between computational thermal stresses and thermal stresses measured on a built-up structure. Element suitability, element density, and computational temperature discrepancies were studied to determine their impact on measured and calculated thermal stress. The optimum number of elements is established from a balance between element density and suitable safety margins, such that the answer is acceptably safe yet is economical from a computational viewpoint. It is noted that situations exist where relatively small excursions of calculated temperatures from measured values result in far more than proportional increases in thermal stress values. Measured residual stresses due to creep significantly exceeded the values computed by the piecewise linear elastic strain analogy approach. The most important element in the computation is the correct definition of the creep law. Computational methodology advances in predicting residual stresses due to creep require significantly more viscoelastic material characterization.

  5. Managing soils for long-term productivity

    PubMed Central

    Syers, J. K.

    1997-01-01

    Meeting the goal of long-term agricultural productivity requires that soil degradation be halted and reversed. Soil fertility decline is a key factor in soil degradation and is probably the major cause of declining crop yields. There is evidence that the contribution of declining soil fertility to soil degradation has been underestimated.
    Sensitivity to soil degradation is implicit in the assessment of the sustainability of land management practices, with wide recognition of the fact that soils vary in their ability to resist change and recover subsequent to stress. The concept of resilience in relation to sustainability requires further elaboration and evaluation.
    In the context of soil degradation, a decline in soil fertility is primarily interpreted as the depletion of organic matter and plant nutrients. Despite a higher turnover rate of organic matter in the tropics there is no intrinsic difference between the organic matter content of soils from tropical and temperate regions. The level of organic matter in a soil is closely related to the above and below ground inputs. In the absence of adequate organic material inputs and where cultivation is continuous, soil organic matter declines progressively. Maintaining the quantity and quality of soil organic matter should be a guiding principle in developing management practices.
    Soil microbial biomass serves as an important reservoir of nitrogen (N), phosphorus (P) and sulphur (S), and regulates the cycling of organic matter and nutrients. Because of its high turnover rate, microbial biomass reacts quickly to changes in management and is a sensitive indicator for monitoring and predicting changes in soil organic matter. Modelling techniques have been reasonably successful in predicting changes in soil organic matter with different organic material inputs, but there is little information from the tropics.
    Nutrient depletion through harvested crop components and residue removal, and by leaching and soil

  6. Scientific Understanding from Long Term Observations: Insights from the Long Term Ecological Research (LTER) Program

    NASA Astrophysics Data System (ADS)

    Gosz, J.

    2001-12-01

    estuaries below by removing all incoming freshwater. At Toolik Lake, long-term experiments of removing top predators from the good web of lakes showed dramatic alterations of lake populations of small fish and zooplankton. In New Mexico, LTER research on small mammal populations is successfully predicting rodent increases and the potential for increased zoonotic diseases such as Hantavirus and bubonic plague. This ability to forecast based on El Nino prediction is being used to increase scientific awareness and public health awareness through media based communication with the public. In Oregon, the Andrews Forest LTER program has had long, strong links with natural resource policy and management. Basic understanding of forest-stream interactions, characteristics of old-growth forests, roles of woody debris in temperate forest ecosystems, invertebrate biodiversity and ecosystem function have been incorporated in management guidelines, plans and regulations for public and private lands throughout the Pacific Northwest. Other examples of the values of long-term research and monitoring will be presented.

  7. Modeling maintenance of long-term potentiation in clustered synapses: long-term memory without bistability.

    PubMed

    Smolen, Paul

    2015-01-01

    Memories are stored, at least partly, as patterns of strong synapses. Given molecular turnover, how can synapses maintain strong for the years that memories can persist? Some models postulate that biochemical bistability maintains strong synapses. However, bistability should give a bimodal distribution of synaptic strength or weight, whereas current data show unimodal distributions for weights and for a correlated variable, dendritic spine volume. Thus it is important for models to simulate both unimodal distributions and long-term memory persistence. Here a model is developed that connects ongoing, competing processes of synaptic growth and weakening to stochastic processes of receptor insertion and removal in dendritic spines. The model simulates long-term (>1 yr) persistence of groups of strong synapses. A unimodal weight distribution results. For stability of this distribution it proved essential to incorporate resource competition between synapses organized into small clusters. With competition, these clusters are stable for years. These simulations concur with recent data to support the "clustered plasticity hypothesis" which suggests clusters, rather than single synaptic contacts, may be a fundamental unit for storage of long-term memory. The model makes empirical predictions and may provide a framework to investigate mechanisms maintaining the balance between synaptic plasticity and stability of memory.

  8. Modeling Maintenance of Long-Term Potentiation in Clustered Synapses: Long-Term Memory without Bistability

    PubMed Central

    Smolen, Paul

    2015-01-01

    Memories are stored, at least partly, as patterns of strong synapses. Given molecular turnover, how can synapses maintain strong for the years that memories can persist? Some models postulate that biochemical bistability maintains strong synapses. However, bistability should give a bimodal distribution of synaptic strength or weight, whereas current data show unimodal distributions for weights and for a correlated variable, dendritic spine volume. Thus it is important for models to simulate both unimodal distributions and long-term memory persistence. Here a model is developed that connects ongoing, competing processes of synaptic growth and weakening to stochastic processes of receptor insertion and removal in dendritic spines. The model simulates long-term (>1 yr) persistence of groups of strong synapses. A unimodal weight distribution results. For stability of this distribution it proved essential to incorporate resource competition between synapses organized into small clusters. With competition, these clusters are stable for years. These simulations concur with recent data to support the “clustered plasticity hypothesis” which suggests clusters, rather than single synaptic contacts, may be a fundamental unit for storage of long-term memory. The model makes empirical predictions and may provide a framework to investigate mechanisms maintaining the balance between synaptic plasticity and stability of memory. PMID:25945261

  9. Layer model for long-term deflection analysis of cracked reinforced concrete bending members

    NASA Astrophysics Data System (ADS)

    Bacinskas, Darius; Kaklauskas, Gintaris; Gribniak, Viktor; Sung, Wen-Pei; Shih, Ming-Hsiang

    2012-05-01

    A numerical technique has been proposed for the long-term deformation analysis of reinforced concrete members subjected to a bending moment. The technique based on the layer approach in a simple and rational way deals with such complex issues as concrete cracking and tension-stiffening as well as creep and shrinkage. The approach uses the material stress-strain relationships for compressive concrete, cracked tensile concrete and steel. Such effects as linear and nonlinear creep, cracking, tension-stiffening as well as the reduction in concrete tension strength due to sustained loading have been taken into account. The shrinkage effect has been modeled by means of adequate actions of axial force and bending moment. A statistical deflection calculation analysis has been carried out for 322 experimental reinforced concrete beams reported in the literature. The comparative analysis of the experimental and the modeling results has shown that the proposed technique has well captured the time-deflection behavior of reinforced concrete flexural members. The results of the predictions by ACI 318 and Eurocode 2 design codes have been also discussed.

  10. Natural History of Cardiac and Respiratory Involvement, Prognosis and Predictive Factors for Long-Term Survival in Adult Patients with Limb Girdle Muscular Dystrophies Type 2C and 2D

    PubMed Central

    Fayssoil, Abdallah; Ogna, Adam; Chaffaut, Cendrine; Chevret, Sylvie; Guimarães-Costa, Raquel; Leturcq, France; Wahbi, Karim; Prigent, Helene; Lofaso, Frederic; Nardi, Olivier; Clair, Bernard; Behin, Anthony; Stojkovic, Tanya; Laforet, Pascal; Orlikowski, David; Annane, Djillali

    2016-01-01

    Background Type 2C and 2D limb girdle muscular dystrophies (LGMD) are a group of autosomal recessive limb girdle muscular dystrophies manifested by proximal myopathy, impaired respiratory muscle function and cardiomyopathy. The correlation and the prognostic impact of respiratory and heart impairment are poorly described. We aimed to describe the long-term cardiac and respiratory follow-up of these patients and to determine predictive factors of cardio-respiratory events and mortality in LGMD 2C and 2D. Methods We reviewed the charts of 34 LGMD patients, followed from 2005 to 2015, to obtain echocardiographic, respiratory function and sleep recording data. We considered respiratory events (acute respiratory failure, pulmonary sepsis, atelectasis or pneumothorax), cardiac events (acute heart failure, significant cardiac arrhythmia or conduction block, ischemic stroke) and mortality as outcomes of interest for the present analysis. Results A total of 21 patients had type 2C LGMD and 13 patients had type 2D. Median age was 30 years [IQR 24–38]. At baseline, median pulmonary vital capacity (VC) was 31% of predicted value [20–40]. Median maximal inspiratory pressure (MIP) was 31 cmH2O [IQR 20.25–39.75]. Median maximal expiratory pressure (MEP) was 30 cm H2O [20–36]. Median left ventricular ejection fraction (LVEF) was 55% [45–64] with 38% of patients with LVEF <50%. Over a median follow-up of 6 years, we observed 38% respiratory events, 14% cardiac events and 20% mortality. Among baseline characteristics, LVEF and left ventricular end diastolic diameter (LVEDD) were associated with mortality, whilst respiratory parameters (VC, MIP, MEP) and the need for home mechanical ventilation (HMV) were associated with respiratory events. Conclusion In our cohort of severely respiratory impaired type 2C and 2D LGMD, respiratory morbidity was high. Cardiac dysfunction was frequent in particular in LGMD 2C and had an impact on long-term mortality. Trial Registration

  11. Clinical risk stratification in the emergency department predicts long-term cardiovascular outcomes in a population-based cohort presenting with acute chest pain: primary results of the Olmsted county chest pain study.

    PubMed

    Farkouh, Michael E; Aneja, Ashish; Reeder, Guy S; Smars, Peter A; Bansilal, Sameer; Lennon, Ryan J; Wiste, Heather J; Razzouk, Louai; Traverse, Kay; Holmes, David R; Mathew, Verghese

    2009-09-01

    The long-term cardiovascular outcomes of a population-based cohort presenting to the emergency department (ED) with chest pain and classified with a clinical risk stratification algorithm are not well documented. The Olmsted County Chest Pain Study is a community-based study that included all consecutive patients presenting with chest pain consistent with unstable angina presenting to all EDs in Olmsted County, Minnesota. Patients were classified according to the Agency for Health Care Policy and Research (AHCPR) criteria. Patients with ST elevation myocardial infarction and chest pain of noncardiac origin were excluded. Main outcome measures were major adverse cardiovascular and cerebrovascular events (MACCE) at 30 days and at a median follow-up of 7.3 years, and mortality through a median of 16.6 years.The 2271 patients were classified as follows: 436 (19.2%) as high risk, 1557 (68.6%) as intermediate risk, and 278 (12.2%) as low risk. Thirty-day MACCE occurred in 11.5% in the high-risk group, 6.2% in the intermediate-risk group, and 2.5% in the low-risk group (p < 0.001). At 7.3 years, significantly more MACCE were recorded in the intermediate-risk (hazard ratio [HR], 1.91; 95% confidence intervals [CI], 1.33-2.75) and high-risk groups (HR, 2.45; 95% CI, 1.67-3.58). Intermediate- and high-risk patients demonstrated a 1.38-fold (95% CI, 0.95-2.01; p = 0.09) and a 1.68-fold (95% CI, 1.13-2.50; p = 0.011) higher mortality, respectively, compared to low-risk patients at 16.6 years. At 7.3 and at 16.6 years of follow-up, biomarkers were not incrementally predictive of cardiovascular risk.In conclusion, a widely applicable rapid clinical algorithm using AHCPR criteria can reliably predict long-term mortality and cardiovascular outcomes. This algorithm, when applied in the ED, affords an excellent opportunity to identify patients who might benefit from a more aggressive cardiovascular risk factor management strategy.

  12. Long-term solar-terrestrial observations

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The results of an 18-month study of the requirements for long-term monitoring and archiving of solar-terrestrial data is presented. The value of long-term solar-terrestrial observations is discussed together with parameters, associated measurements, and observational problem areas in each of the solar-terrestrial links (the sun, the interplanetary medium, the magnetosphere, and the thermosphere-ionosphere). Some recommendations are offered for coordinated planning for long-term solar-terrestrial observations.

  13. An Exotic Long-Term Pattern in Stock Price Dynamics

    PubMed Central

    Wei, Jianrong; Huang, Jiping

    2012-01-01

    Background To accurately predict the movement of stock prices is always of both academic importance and practical value. So far, a lot of research has been reported to help understand the behavior of stock prices. However, some of the existing theories tend to render us the belief that the time series of stock prices are unpredictable on a long-term timescale. The question arises whether the long-term predictability exists in stock price dynamics. Methodology/Principal Findings In this work, we analyze the price reversals in the US stock market and the Chinese stock market on the basis of a renormalization method. The price reversals are divided into two types: retracements (the downward trends after upward trends) and rebounds (the upward trends after downward trends), of which the intensities are described by dimensionless quantities, and , respectively. We reveal that for both mature and emerging markets, the distribution of either retracements or rebounds shows two characteristic values, 0.335 and 0.665, both of which are robust over the long term. Conclusions/Significance The methodology presented here provides a way to quantify the stock price reversals. Our findings strongly support the existence of the long-term predictability in stock price dynamics, and may offer a hint on how to predict the long-term movement of stock prices. PMID:23284734

  14. Associations of dietary fiber intake with long-term predicted cardiovascular disease risk and C-reactive protein levels (from the National Health and Nutrition Examination Survey Data [2005-2010]).

    PubMed

    Ning, Hongyan; Van Horn, Linda; Shay, Christina M; Lloyd-Jones, Donald M

    2014-01-15

    Dietary fiber intake might reduce cardiovascular risk factor levels and, in turn, might lower the long-term risk of cardiovascular disease (CVD). A total of 11,113 subjects, aged 20 to 79 years with no history of CVD, from the 2005 to 2010 National Health and Nutrition Examination Survey were included in the present study to examine associations of dietary fiber intake with predicted lifetime CVD risk and C-reactive protein levels. Dietary fiber intake showed a significant gradient association with the likelihood of having a low or an intermediate predicted lifetime CVD risk among young and middle-age adults. In fully adjusted multinomial logistic models, dietary fiber intake was related to a low lifetime CVD risk with an odds ratio of 2.71 (95% confidence interval 2.05 to 3.59) in the young adults and 2.13 (95% confidence interval 1.42 to 3.20) in the middle-age adults and was related to an intermediate lifetime risk of 2.65 (95% confidence interval 1.79 to 3.92) in the young and 1.98 (95% confidence interval 1.32 to 2.98) in the middle-age adults compared with a high lifetime risk. A significant inverse linear association was seen between dietary fiber intake and log-transformed C-reactive protein levels with a regression coefficient ± standard error of -0.18 ± 0.04 in the highest quartile of fiber intake compared with the lowest fiber intake. In conclusion, these data suggest that dietary fiber intake is independently associated with the predicted lifetime CVD risk, especially in young and middle-age adults. A greater amount of dietary fiber intake might be associated with lower C-reactive protein levels.

  15. Interpretation of changes in water level accompanying fault creep and implications for earthquake prediction.

    USGS Publications Warehouse

    Wesson, R.L.

    1981-01-01

    Quantitative calculations for the effect of a fault creep event on observations of changes in water level in wells provide an approach to the tectonic interpretation of these phenomena. For the pore pressure field associated with an idealized creep event having an exponential displacement versus time curve, an analytic expression has been obtained in terms of exponential-integral functions. The pore pressure versus time curves for observation points near the fault are pulselike; a sharp pressure increase (or decrease, depending on the direction of propagation) is followed by more gradual decay to the normal level after the creep event. The time function of the water level change may be obtained by applying the filter - derived by A.G.Johnson and others to determine the influence of atmospheric pressure on water level - to the analytic pore pressure versus time curves. The resulting water level curves show a fairly rapid increase (or decrease) and then a very gradual return to normal. The results of this analytic model do not reproduce the steplike changes in water level observed by Johnson and others. If the procedure used to obtain the water level from the pore pressure is correct, these results suggest that steplike changes in water level are not produced by smoothly propagating creep events but by creep events that propagate discontinuously, by changes in the bulk properties of the region around the well, or by some other mechanism.-Author

  16. Deterministic Multiaxial Creep and Creep Rupture Enhancements for CARES/Creep Integrated Design Code

    NASA Technical Reports Server (NTRS)

    Jadaan, Osama M.

    1998-01-01

    High temperature and long duration applications of monolithic ceramics can place their failure mode in the creep rupture regime. A previous model advanced by the authors described a methodology by which the creep rupture life of a loaded component can be predicted. That model was based on the life fraction damage accumulation rule in association with the modified Monkman-Grant creep rupture criterion. However, that model did not take into account the deteriorating state of the material due to creep damage (e.g., cavitation) as time elapsed. In addition, the material creep parameters used in that life prediction methodology, were based on uniaxial creep curves displaying primary and secondary creep behavior, with no tertiary regime. The objective of this paper is to present a creep life prediction methodology based on a modified form of the Kachanov-Rabotnov continuum damage mechanics (CDM) theory. In this theory, the uniaxial creep rate is described in terms of sum, temperature, time, and the current state of material damage. This scalar damage state parameter is basically an abstract measure of the current state of material damage due to creep deformation. The damage rate is assumed to vary with stress, temperature, time, and the current state of damage itself. Multiaxial creep and creep rupture formulations of the CDM approach are presented in this paper. Parameter estimation methodologies based on nonlinear regression analysis are also described for both, isothermal constant stress states and anisothermal variable stress conditions This creep life prediction methodology was preliminarily added to the integrated design code CARES/Creep (Ceramics Analysis and Reliability Evaluation of Structures/Creep), which is a postprocessor program to commercially available finite element analysis (FEA) packages. Two examples, showing comparisons between experimental and predicted creep lives of ceramic specimens, are used to demonstrate the viability of Ns methodology and the

  17. Predictive calculations to assess the long-term effect of cementitious materials on the pH and solubility of uranium(VI) in a shallow land disposal environment

    SciTech Connect

    Criscenti, L.J.; Serne, R.J.; Krupka, K.M.; Wood, M.I.

    1996-09-01

    One proposed method of low-level radioactive waste (LLW) disposal is to mix the radioactive waste streams with cement, place the mixture in steel barrels, and dispose of the barrels in near-surface unsaturated sediments. Cement or concrete is frequently used in burial grounds, because cement porewaters are buffered at high pH values and lanthanides and actinides; are very insoluble in highly alkaline environments. Therefore, leaching of these contaminants from the combined cement/low-level radioactive waste streams will at least initially be retarded. The calculations performed in this study demonstrate that the pH of cement porewaters will be maintained at a value greater than 10 for 10,000 years under Hanford specific hydrogeochemical conditions. Ten thousand years is the period generally studied in longterm performance assessments per regulatory guidance. The concentrations of dissolved hexavalent uranium [U(VI)], the valence form of dissolved U usually present in oxidizing surface and groundwaters, are also constrained by the high pH and predicted solution compositions over the 10,000-year period, which is favorable from a long-term performance perspective.

  18. Characterization of the Dynamics of Climate Systems and Identification of Missing Mechanisms Impacting the Long Term Predictive Capabilities of Global Climate Models Utilizing Dynamical Systems Approaches to the Analysis of Observed and Modeled Climate

    SciTech Connect

    Bhatt, Uma S.; Wackerbauer, Renate; Polyakov, Igor V.; Newman, David E.; Sanchez, Raul E.

    2015-11-13

    The goal of this research was to apply fractional and non-linear analysis techniques in order to develop a more complete characterization of climate change and variability for the oceanic, sea ice and atmospheric components of the Earth System. This research applied two measures of dynamical characteristics of time series, the R/S method of calculating the Hurst exponent and Renyi entropy, to observational and modeled climate data in order to evaluate how well climate models capture the long-term dynamics evident in observations. Fractional diffusion analysis was applied to ARGO ocean buoy data to quantify ocean transport. Self organized maps were applied to North Pacific sea level pressure and analyzed in ways to improve seasonal predictability for Alaska fire weather. This body of research shows that these methods can be used to evaluate climate models and shed light on climate mechanisms (i.e., understanding why something happens). With further research, these methods show promise for improving seasonal to longer time scale forecasts of climate.

  19. Virtual Models of Long-Term Care

    ERIC Educational Resources Information Center

    Phenice, Lillian A.; Griffore, Robert J.

    2012-01-01

    Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

  20. Long Term Preservation of Digital Information.

    ERIC Educational Resources Information Center

    Lorie, Raymond A.

    The preservation of digital data for the long term presents a variety of challenges from technical to social and organizational. The technical challenge is to ensure that the information, generated today, can survive long term changes in storage media, devices, and data formats. This paper presents a novel approach to the problem. It distinguishes…

  1. Long-Term Nutrition: A Clinician's Guide to Successful Long-Term Enteral Access in Adults.

    PubMed

    Bechtold, Matthew L; Mir, Fazia A; Boumitri, Christine; Palmer, Lena B; Evans, David C; Kiraly, Laszlo N; Nguyen, Douglas L

    2016-09-22

    Long-term nutrition support requires long-term enteral access. To ensure the success of long-term enteral access, many factors need to be taken into consideration. This article represents a guide to placing and maintaining access in patients requiring long-term nutrition and addresses many of the common questions regarding long-term enteral access, such as indications, types of access, feeding after access placed, and recognition and treatment of potential complications. This guide will help the clinician establish and maintain access to maximize nutrition in patients requiring long-term nutrition.

  2. Paying for long-term care.

    PubMed Central

    Estes, C L; Bodenheimer, T

    1994-01-01

    Everyone agrees that insurance for long-term care is inadequate in the United States. Disagreement exists, however, on whether such insurance should be provided through the private or public sector. Private insurance generally uses the experience-rating principle that persons with higher risk of illness are charged higher premiums. For private insurance for long-term care, this principle creates a dilemma. Most policies will be purchased by the elderly; yet, because the elderly have a high risk of needing long-term care, only about 20% of them can afford the cost of premiums. A public-private partnership by which the government partially subsidizes private long-term-care insurance is unlikely to resolve this dilemma. Only a social insurance program for long-term care can provide universal, affordable, and equitable coverage. PMID:8128712

  3. [Classification of endogenous psychoses. Predictive validity of initial diagnosis based on 5 and 21-33-years of follow-up in a long-term prospective study (Budapest 2000)].

    PubMed

    Pethö, Bertalan; Tolna, Judit; Farkas, Márta; Vízkeleti, Györgyi; Czobor, Pál

    2011-01-01

    As regards the clinical psychopathological diagnostics, Leonhard's classification of endogenous psychoses published in 1957 contained description of a detailed nosology with claims that the diagnostic categories included in this classification system involve differentiated predictions of course and outcome of the illness. The principal investigator (BP) chose Leonhard's classification system to test these nosological hypotheses via a prospective study of psychotic patients based on their clinical and life history in 1966-67. Validity of the categorial diagnoses given at baseline (female patients n=222; healthy control persons n=54; 1968-1976) was proven by combination of assessments of psychopathological symptoms and personality types at the 5-year follow-up. Moreover, "pure defect" also proved to be valid (84,6%). At the time of the long-term follow-up in 1997-2002 (patients: n=125; healthy control persons: n=38) predictive validity of the nine categories was measured empirically and by using a stochastic (Markovian) model, thus combining validity and reliability. Hebephrenias, group of normal persons and of schizophrenias proved to be valid, with diagnostic stabilities of 0,93, 0,89, and 0,93, for the three groups, respectively. In addition, bipolar manic-depressive psychoses and cycloid psychoses were also valid (diagnostic stability of 0,76 in both cases). Unipolar depression was valid (diagnostic stability=0,84) only by forming a "nosological family" based on diagnostic stability and on current status and clinical presentation during the period preceeding the follow-up with regard to other moodcongruent disorders and outcome-diagnosis "healthy control". Validity of systematic paraphrenias (diagnostic stability =0,68) was also in the moderate range. Division of schizophrenias in "systematic vs. non-systematic" nosological categories was inconclusive; the categories of affect-laden paraphrenia, periodic catatonia and systematic catatonias could not be confirmed

  4. Seven-year increase in exercise systolic blood pressure at moderate workload predicts long-term risk of coronary heart disease and mortality in healthy middle-aged men.

    PubMed

    Skretteberg, Per Torger; Grundvold, Irene; Kjeldsen, Sverre E; Engeseth, Kristian; Liestøl, Knut; Erikssen, Gunnar; Erikssen, Jan; Gjesdal, Knut; Bodegard, Johan

    2013-05-01

    Exercise systolic blood pressure (SBP) predicts coronary heart disease (CHD) in the general population. We tested whether changes in exercise SBP during 7 years predict CHD (including angina pectoris, nonfatal myocardial infarction, and fatal CHD) and mortality over the following 28 years. Peak SBP at 100 W workload (=5.5 METS [metabolic equivalents]; completed by all participants) was measured among 1392 apparently healthy men in 1972-75 and repeated in 1979-82. The men were divided into quartiles (Q1-Q4) of exercise SBP change. Relative risks were calculated using Cox proportional hazard regression adjusting for family history of CHD, age, smoking status, resting SBP, peak SBP at 100 W, total cholesterol at first examination (model 1), and further for physical fitness and change in physical fitness (model 2). The highest quartile, Q4, was associated with a 1.55-fold (95% confidence interval, 1.17-2.03) adjusted (model 1) risk of CHD and a 1.93-fold (1.24-3.02) risk of coronary heart death compared with the lowest, Q1. Q4 had a 1.40-fold (1.06-1.85) risk of CHD and a 1.70-fold (1.08-2.68) risk of coronary heart death using model 2. Q4 was associated with increased risk of cardiovascular death and all-cause death compared with Q1 in model 1, but not in model 2. Our results indicate that an increase in exercise SBP at 100 W over 7 years is independently associated with increased long-term risk of CHD and substantiate our previous finding that high exercise SBP is an important risk factor for CHD in healthy men.

  5. The effect of openings on the long term deflection and flexural capacity of laminated veneer lumber (LVL)

    NASA Astrophysics Data System (ADS)

    Mancini, Matthew L.

    In most residential construction projects, laminated veneer lumber (LVL) beams are used to help support floor systems, and span doorways or garage door openings, amongst other applications. Because of its diverse application, it is not uncommon that openings are drilled through LVL beams to allow for the passage of utilities. This research evaluates the effects these openings have on long term deflection and flexural capacity, and looks to determine if current provisions for openings need to be amended. Two separate tests were conducted to analyze these behaviors. A long term flexural test was completed to determine the relative creep behavior, and an ultimate load test was conducted to determine the failure load under bending. A total of 26 beams (13 total samples) were tested in the long term test, which included beams with 5 different hole patterns loaded to either 50% or 75% of the allowable load set by the manufacturer. Each beam was loaded for over a year, and its midspan deflection and moisture content was monitored periodically. The environmental conditions such as relative humidity and temperature were also carefully monitored to determine if there was a correlation between relative humidity and long term deflection. Seven of the samples from the long term test were used in the ultimate load test, which included a control sample that was loaded to 60% of the predicted ultimate load so that it could continue being used as a control for the long term test. During the ultimate load test the midpsan and quarterspan deflections were recorded using LVDTs, and the total load was monitored via 4 load cells evenly spaced along the sample. This study found that 2" diameter openings placed in the middle third of the beam length and depth do not significantly affect the long term deflection or flexural capacity of LVL beams. However, as the 2" diameter openings are shifted away from the beam centroid, there is an evident decrease in overall performance in terms of

  6. Dilution as a Model of Long-Term Forgetting

    ERIC Educational Resources Information Center

    Lansdale, Mark; Baguley, Thom

    2008-01-01

    This article presents a model of long term forgetting based on 3 ideas: (a) Memory for a stimulus can be described by a population of accessible traces; (b) probability of retrieval after a delay is predicted by the proportion of traces in this population that will be defined as correct if sampled; and (c) this population is diluted over time by…

  7. The Long-Term Effects of Youth Unemployment

    ERIC Educational Resources Information Center

    Mroz, Thomas A.; Savage, Timothy H.

    2006-01-01

    Using NLSY data, we examine the long-term effects of youth unemployment on later labor market outcomes. Involuntary unemployment may yield suboptimal investments in human capital in the short run. A theoretical model of dynamic human capital investment predicts a rational "catch-up" response. Using semiparametric techniques to control for the…

  8. Method for Water Management Considering Long-term Probabilistic Forecasts

    NASA Astrophysics Data System (ADS)

    Hwang, J.; Kang, J.; Suh, A. S.

    2015-12-01

    This research is aimed at predicting the monthly inflow of the Andong-dam basin in South Korea using long-term probabilistic forecasts to apply long-term forecasts to water management. Forecasted Cumulative Distribution Functions (CDFs) of monthly precipitation are plotted by combining the range of monthly precipitation based on proper Probability Density Function (PDF) in past data with probabilistic forecasts in each category. Ensembles of inflow are estimated by entering generated ensembles of precipitation based on the CDFs into the 'abcd' water budget model. The bias and RMSE between averages in past data and observed inflow are compared to them in forecasted ensembles. In our results, the bias and RMSE of average precipitation in the forecasted ensemble are bigger than in past data, whereas the average inflow in the forecasted ensemble is smaller than in past data. This result could be used for reference data to apply long-term forecasts to water management, because of the limit in the number of forecasted data for verification and differences between the Andong-dam basin and the forecasted regions. This research has significance by suggesting a method of applying probabilistic information in climate variables from long-term forecasts to water management in Korea. Original data of a climate model, which produces long-term probabilistic forecasts should be verified directly as input data of a water budget model in the future, so that a more scientific response in water management against uncertainty of climate change could be reached.

  9. Roadmap to Long-Term Monitoring Optimization

    EPA Pesticide Factsheets

    This roadmap focuses on optimization of established long-term monitoring programs for groundwater. Tools and techniques discussed concentrate on methods for optimizing the monitoring frequency and spatial (three-dimensional) distribution of wells ...

  10. Mental Health in Long Term Care Settings.

    ERIC Educational Resources Information Center

    Shore, Herbert

    1978-01-01

    There are many ways in which long-term care facilities attempt to cope with the mental health problems of the elderly. The author reviews five factors crucial to effective care for the aged in these facilities. (Author/RK)

  11. Long-term-care legal update.

    PubMed

    Fiesta, J

    1998-04-01

    As more nurses move from the acute care setting to long-term-care and home health care, different practice issues arise. To maximize liability protection, nurses must understand the legal issues unique to each delivery system.

  12. Long-Term Care Ombudsman Program

    MedlinePlus

    ... Provided to Persons Living in Long-Term Care Facilities Program data for FY 2013 indicate that long- ... least quarterly Conducted 5,417 training sessions in facilities on such topics as residents’ rights Provided 129, ...

  13. Short and long-term strength of shale rocks

    NASA Astrophysics Data System (ADS)

    Rybacki, Erik; Dresen, Georg

    2016-04-01

    Stimulation of oil and gas bearing shales commonly utilizes advanced hydraulic fracturing techniques to enhance the production rate. Successful hydrofrac campaigns depend on the geomechanical properties of the reservoir. For example, the short term strength and brittleness may control the hydraulic breakdown pressure and borehole stability. The long term creep properties may determine the closure rate of hydraulically induced fractures, for example by proppant embedment. We performed a series of mechanical tests on shales with different mineral content, porosity and maturity. Cylindrical samples of 1-5 cm in diameter and 2-10 cm in length were deformed at confining pressures of 0.1 - 400 MPa and temperatures of 25°-400°C in constant strain rate and constant stress mode in order to evaluate the influence of loading conditions and composition on their strength and ductility. Short-term constant strain rate tests show that, at fixed loading direction with respect to bedding orientation, the peak strength and Young's modulus vary with mineral content, humidity and porosity, but depend also on applied pressure, temperature and strain rate. The (porosity-corrected) variation of peak strength and Young's modulus with composition can be roughly estimated from the mechanical behavior of all components at given pressure-temperature conditions and their volumetric proportion. Samples deforming in the brittle-semibrittle regime may be characterized by empirical brittleness indices based on their deformation behavior, Young's modulus, or bulk composition. These indices are correlated at low pressure-temperature conditions (corresponding to < about 4 km depth). First long-term deformation experiments at constant load show transient viscoplastic creep behavior. The associated strain rates increase with increasing differential stress, increasing temperature and decreasing pressure, accompanied by slight porosity reduction. Therefore, estimates of fracture healing rates by

  14. Long-term multipactor discharge in multicarrier systems

    SciTech Connect

    Anza, S.; Vicente, C.; Gimeno, B.; Boria, V. E.; Armendariz, J.

    2007-08-15

    A new mechanism of long-term multipactor in multicarrier systems is studied employing both analytical and numerical methods. In particular, the investigation is focused on the impact that a realistic secondary emission yield at low energies produces on the development of long term multipactor. A novel analytical model for this interperiod charge accumulation is presented using the traditional multipactor theory for parallel plates, and approximating the multicarrier signal as a single-carrier signal modulated by a pulsed signal envelope. The analytical predictions are verified by numerical simulations for a typical rectangular waveguide. The analytical and numerical results demonstrate that the susceptibility of the system to develop a long-term multipactor discharge increases with higher values of low-energy secondary emission yield.

  15. Stirling engine - Approach for long-term durability assessment

    NASA Astrophysics Data System (ADS)

    Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

    The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

  16. The 2014 Long-Term Budget Outlook

    DTIC Science & Technology

    2014-07-16

    Treasury from the Federal Reserve System, customs duties, estate and gift taxes, and miscellaneous fees and fines. Actual Extended Baseline...Office’s (CBO’s) most recent analysis of the outlook for the federal budget over the long term. My statement today summarizes The 2014 Long-Term Budget...Outlook, which was released yesterday.1 Between 2009 and 2012, the federal government recorded the largest budget deficits relative to the size of

  17. Evidence-based long term care design.

    PubMed

    Calkins, Margaret P

    2009-01-01

    Research on the impact of the built environment in long-term care settings continues to grow. This article focuses on work conducted and published since 2000, when an earlier review on research on dementia and design was published. The vast majority of research that addressed neurological conditions in residents in long-term care settings (assisted living and nursing homes) relates to Alzheimer's disease and related dementias.

  18. Long Term Outcomes after Pediatric Liver Transplantation

    PubMed Central

    2013-01-01

    Long term outcomes after liver transplantation are major determinants of quality of life and of the value of this heroic treatment. As short term outcomes are excellent, our community is turning to take a harder look at long term outcomes. The purpose of this paper is to review these outcomes, and highlight proposed treatments, as well as pressing topics needing to be studied. A systemic review of the English literature was carried in PubMed, covering all papers addressing long term outcomes in pediatric liver transplant from 2000-2013. Late outcomes after pediatric liver transplant affect the liver graft in the form of chronic liver dysfunction. The causes include rejection particularly humoral rejection, but also de novo autoimmune hepatitis, and recurrent disease. The metabolic syndrome is a major factor in long term cardiovascular complication risk. Secondary infections, kidney dysfunction and malignancy remain a reality of those patients. There is growing evidence of late cognitive and executive function delays affecting daily life productivity as well as likely adherence. Finally, despite a good health status, quality of life measures are comparable to those of children with chronic diseases. Long term outcomes are the new frontier in pediatric liver transplantation. Much is needed to improve graft survival, but also to avoid systemic morbidities from long term immunosuppression. Quality of life is a new inclusive measure that will require interventions and innovative approaches respectful not only on the patients but also of their social circle. PMID:24511516

  19. Application of the cracked pipe element to creep crack growth prediction

    SciTech Connect

    Brochard, J.; Charras, T.

    1997-04-01

    The modification of a computer code for leak before break analysis is very briefly described. The CASTEM2000 code was developed for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading. The modification extends the capabilities of the cracked pipe element to the determination of fracture parameters under creep conditions (C*, {phi}c and {Delta}c). The model has the advantage of evaluating significant secondary effects, such as those from thermal loading.

  20. Long term integrity for space station power systems

    NASA Technical Reports Server (NTRS)

    Leckie, F. A.; Marriott, D. L.

    1991-01-01

    A study was made of the High Temperature Design Codes ASME N47, British R5, and the French RCC-MR Rules. It is concluded that all these codes provide a good basis of design for space application. The new British R5 is the most complete since it deals with the problem of defects. The ASME N47 was subjected longer to practical application and scrutiny. A draft code is introduced, and a proposed draft for high temperature design in which attempts were made to identify gaps and improvements is suggested. The design is limited by creep characteristics. In these circumstances, life is strongly affected by the selected value of the factor of safety. The factor of safety of primary loads adopted in the codes is 1.5. Maybe a lower value of 1.25 is permissible for use in space. Long term creep rupture data for HAYNES 188 is deficient and it is suggested that extrapolation methods be investigated.

  1. Relating Granger causality to long-term causal effects.

    PubMed

    Smirnov, Dmitry A; Mokhov, Igor I

    2015-10-01

    In estimation of causal couplings between observed processes, it is important to characterize coupling roles at various time scales. The widely used Granger causality reflects short-term effects: it shows how strongly perturbations of a current state of one process affect near future states of another process, and it quantifies that via prediction improvement (PI) in autoregressive models. However, it is often more important to evaluate the effects of coupling on long-term statistics, e.g., to find out how strongly the presence of coupling changes the variance of a driven process as compared to an uncoupled case. No general relationships between Granger causality and such long-term effects are known. Here, we pose the problem of relating these two types of coupling characteristics, and we solve it for a class of stochastic systems. Namely, for overdamped linear oscillators, we rigorously derive that the above long-term effect is proportional to the short-term effects, with the proportionality coefficient depending on the prediction interval and relaxation times. We reveal that this coefficient is typically considerably greater than unity so that small normalized PI values may well correspond to quite large long-term effects of coupling. The applicability of the derived relationship to wider classes of systems, its limitations, and its value for further research are discussed. To give a real-world example, we analyze couplings between large-scale climatic processes related to sea surface temperature variations in equatorial Pacific and North Atlantic regions.

  2. Relating Granger causality to long-term causal effects

    NASA Astrophysics Data System (ADS)

    Smirnov, Dmitry A.; Mokhov, Igor I.

    2015-10-01

    In estimation of causal couplings between observed processes, it is important to characterize coupling roles at various time scales. The widely used Granger causality reflects short-term effects: it shows how strongly perturbations of a current state of one process affect near future states of another process, and it quantifies that via prediction improvement (PI) in autoregressive models. However, it is often more important to evaluate the effects of coupling on long-term statistics, e.g., to find out how strongly the presence of coupling changes the variance of a driven process as compared to an uncoupled case. No general relationships between Granger causality and such long-term effects are known. Here, we pose the problem of relating these two types of coupling characteristics, and we solve it for a class of stochastic systems. Namely, for overdamped linear oscillators, we rigorously derive that the above long-term effect is proportional to the short-term effects, with the proportionality coefficient depending on the prediction interval and relaxation times. We reveal that this coefficient is typically considerably greater than unity so that small normalized PI values may well correspond to quite large long-term effects of coupling. The applicability of the derived relationship to wider classes of systems, its limitations, and its value for further research are discussed. To give a real-world example, we analyze couplings between large-scale climatic processes related to sea surface temperature variations in equatorial Pacific and North Atlantic regions.

  3. Long-term symptom relief after septoplasty.

    PubMed

    Sundh, Carolina; Sunnergren, Ola

    2015-10-01

    The results for long-term symptom relief after septoplasty are contradictory in reviewed publications but the findings suggest that results are unsatisfactory. In this study, we analyzed and compared short- and long-term symptom relief after septoplasty and factors possibly associated with symptom relief. 111 patients that underwent septoplasty between 2008 and 2010 were included in the study. Medical charts were reviewed for preoperative characteristics and assessments. Data on short-term symptom relief (6 months) were retrieved from the Swedish National Quality Registry for Septoplasty; data on long-term symptom relief (34-70 months) were collected through a questionnaire. Upon the 34-70 month follow-up, 53% of the patients reported that symptoms either remained or had worsened and 83% reported nasal obstruction. Degree of symptom relief was significantly higher among patients not reporting nasal obstruction than among patients reporting nasal obstruction at long-term follow-up. The proportion of patients that reported "my symptoms are gone" declined from 53% after 6 months to 18% after 34-70 months. None of the factors taken into consideration, age at surgery, gender, follow-up time, primary operation/reoperation, history of nasal trauma, self-reported allergy, rhinometric obstruction, or same sided rhinometric, clinical and subjective nasal obstruction were associated with symptom relief. The long-term results after septoplasty are unsatisfactory. A majority of patients report that their symptoms remain after septoplasty.

  4. Long-term outcomes of autoimmune pancreatitis

    PubMed Central

    Ikeura, Tsukasa; Miyoshi, Hideaki; Shimatani, Masaaki; Uchida, Kazushige; Takaoka, Makoto; Okazaki, Kazuichi

    2016-01-01

    Autoimmune pancreatitis (AIP) has been considered a favorable-prognosis disease; however, currently, there is limited information on natural course of AIP during long-term follow-up. Recently published studies regarding the long-term outcomes of AIP has demonstrated the developments of pancreatic stone formation, exocrine insufficiency, and endocrine insufficiency are observed in 5%-41%, 34%-82%, and 38%-57% of patients having the disease. Furthermore, the incidence rate of developing pancreatic cancer ranges from 0% to 4.8% during the long-term follow-up. The event of death from AIP-related complications other than accompanying cancer is likely to be rare. During follow-up of AIP patients, careful surveillance for not only relapse of the disease but also development of complications at regular intervals is needed. PMID:27678359

  5. Creep, fatigue and creep-fatigue interactions in modified 9% Chromium - 1% Molybdenum (P91) steels

    NASA Astrophysics Data System (ADS)

    Kalyanasundaram, Valliappa

    Grade P91 steel, from the class of advanced high-chrome ferritic steels, is one of the preferred materials for many elevated temperature structural components. Creep-fatigue (C-F) interactions, along with oxidation, can accelerate the kinetics of damage accumulation and consequently reduce such components' life. Hence, reliable C-F test data is required for meticulous consideration of C-F interactions and oxidation, which in turn is vital for sound design practices. It is also imperative to develop analytical constitutive models that can simulate and predict material response under various long-term in-service conditions using experimental data from short-term laboratory experiments. Consequently, the major objectives of the proposed research are to characterize the creep, fatigue and C-F behavior of grade P91 steels at 625 C and develop robust constitutive models for simulating/predicting their microstructural response under different loading conditions. This work will utilize experimental data from 16 laboratories worldwide that conducted tests (creep, fatigue and C-F) on grade P91 steel at 625°C in a round-robin (RR) program. Along with 7 creep deformation and rupture tests, 32 pure fatigue and 46 C-F tests from the RR are considered in this work. A phenomenological constitutive model formulated in this work needs just five fitting parameters to simulate/predict the monotonic, pure fatigue and C-F behavior of grade P91 at 625 C. A modified version of an existing constitutive model is also presented for particularly simulating its isothermal creep deformation and rupture behavior. Experimental results indicate that specimen C-F lives, as measured by the 2% load drop criterion, seem to decrease with increasing strain ranges and increasing hold times at 625°C. Metallographic assessment of the tested specimens shows that the damage mode in both pure fatigue and 600 seconds hold time cyclic tests is predominantly transgranular fatigue with some presence of

  6. Valuing a long-term care facility.

    PubMed

    Mellen, C M

    1992-10-01

    The business valuation industry generally uses at least one of three basic approaches to value a long-term care facility: the cost approach, sales comparison approach, or income approach. The approach that is chosen and the resulting weight that is applied to it depend largely on the circumstances involved. Because a long-term care facility is a business enterprise, more weight usually is given to the income approach which factors into the estimate of value both the tangible and intangible assets of the facility.

  7. Keratoprosthesis: a long-term review.

    PubMed Central

    Barnham, J. J.; Roper-Hall, M. J.

    1983-01-01

    A keratoprosthesis (KP), is an artificial cornea which is inserted into an opacified cornea in an attempt to restore useful vision or, less commonly, to make the eye comfortable in painful keratopathy. Results o a retrospective study of 35 patients, with 55 KP insertions, are reviewed with regard to visual acuity, length of time vision is maintained, retention time, and complication. Overall there were a number of long-term real successes, eith retention of the KP and maintenance of improved vision in eyes not amenable to conventional treatment. Careful long-term follow-up was needed, with further surgical procedures often being necessary. Images PMID:6860613

  8. Long-term outcomes after severe shock.

    PubMed

    Pratt, Cristina M; Hirshberg, Eliotte L; Jones, Jason P; Kuttler, Kathryn G; Lanspa, Michael J; Wilson, Emily L; Hopkins, Ramona O; Brown, Samuel M

    2015-02-01

    Severe shock is a life-threatening condition with very high short-term mortality. Whether the long-term outcomes among survivors of severe shock are similar to long-term outcomes of other critical illness survivors is unknown. We therefore sought to assess long-term survival and functional outcomes among 90-day survivors of severe shock and determine whether clinical predictors were associated with outcomes. Seventy-six patients who were alive 90 days after severe shock (received ≥1 μg/kg per minute of norepinephrine equivalent) were eligible for the study. We measured 3-year survival and long-term functional outcomes using the Medical Outcomes Study 36-Item Short-Form Health Survey, the EuroQOL 5-D-3L, the Hospital Anxiety and Depression Scale, the Impact of Event Scale-Revised, and an employment instrument. We also assessed the relationship between in-hospital predictors and long-term outcomes. The mean long-term survival was 5.1 years; 82% (62 of 76) of patients survived, of whom 49 were eligible for follow-up. Patients who died were older than patients who survived. Thirty-six patients completed a telephone interview a mean of 5 years after hospital admission. The patients' Physical Functioning scores were below U.S. population norms (P < 0.001), whereas mental health scores were similar to population norms. Nineteen percent of the patients had symptoms of depression, 39% had symptoms of anxiety, and 8% had symptoms of posttraumatic stress disorder. Thirty-six percent were disabled, and 17% were working full-time. Early survivors of severe shock had a high 3-year survival rate. Patients' long-term physical and psychological outcomes were similar to those reported for cohorts of less severely ill intensive care unit survivors. Anxiety and depression were relatively common, but only a few patients had symptoms of posttraumatic stress disorder. This study supports the observation that acute illness severity does not determine long-term outcomes. Even extremely

  9. [Fetal pain: immediate and long term consequences].

    PubMed

    Houfflin Debarge, Véronique; Dutriez, Isabelle; Pusniak, Benoit; Delarue, Eléonore; Storme, Laurent

    2010-06-01

    Several situations are potentially painful for fetuses, such as malformations and invasive procedures. Nociceptive pathways are known to be functional at 26 weeks. Even if it is not possible to evaluate the fetal experience of pain, it is essential to examine its immediate and long-term consequences. As early as the beginning of the second trimester, hemodynamic and hormonal responses are observed following fetal nociceptive stimulation, In experimental studies, long-term changes have been noted in the corticotrop axis, subsequent responses to pain, and behavior after perinatal nociceptive stimulation.

  10. The Role of Eta Phase Formation on the Creep Strength and Ductility of INCONEL Alloy 740 t 1023 k (750 Degrees C)

    SciTech Connect

    Shingledecker, John P; Pharr, George Mathews

    2012-01-01

    INCONEL alloy 740 is an age-hardenable nickel-based superalloy proposed for advanced ultrasupercritical steam boiler applications operating at high stress and long times above 973 K (700 C), where creep will be the dominate deformation mode. During high-temperature exposure, the alloy can form eta phase platelets that many have suggested may be detrimental to creep strength and ductility. In this study, creep-rupture tests were conducted on smooth and notched bars of INCONEL alloy 740 at 1023 K (750 C) for times up to 20,000 hours. Examination of the creep-rupture life, creep ductility, failure modes, and microstructure by quantitative electron microscopy shows that a small amount of eta phase does not diminish the creep performance. Applied stress appears to have a minor effect on the precipitation of the eta phase but not its growth rate. Based on the observation that the microstructure after 20,000 hours of creep exposure has reached equilibrium in comparison to thermodynamic calculations, it is concluded that 20,000 hour creep tests are adequate for prediction of long-term creep performance.

  11. Long-term studies of dopamine agonists.

    PubMed

    Hubble, Jean P

    2002-02-26

    Dopamine agonists have long been used as adjunctive therapy for the treatment of Parkinson's disease (PD). In more recent years these drugs have also been proved safe and effective as initial therapy in lieu of levodopa in the treatment of PD. Long-term levodopa therapy is associated with motor complications, including fluctuating response patterns and dyskinesia. By initially introducing a dopamine agonist as symptomatic drug therapy, it may be possible to postpone the use of levodopa and delay or prevent the development of motor complications. Recently, four clinical trials have explored this hypothesis by comparing the long-term response and side effects of levodopa with dopamine agonist therapy. The drugs studied have included ropinirole, pramipexole, cabergoline, and pergolide. In each of these projects, the occurrence of motor complications, such as wearing off and dyskinesia, was significantly less in the subjects assigned to initiation of therapy with a dopamine agonist. The addition of levodopa could be postponed by many months or even several years. Therefore, these long-term studies of dopamine agonists support the initiation of a dopamine agonist instead of levodopa in an effort to postpone levodopa-related motor complications. This therapeutic approach may be particularly appropriate in PD patients with a long treatment horizon on the basis of age and general good health. The extension phase of the long-term study comparing pramipexole with levodopa is ongoing, and follow-up information may help to establish the value of this treatment strategy.

  12. Long-Term Memory and Learning

    ERIC Educational Resources Information Center

    Crossland, John

    2011-01-01

    The English National Curriculum Programmes of Study emphasise the importance of knowledge, understanding and skills, and teachers are well versed in structuring learning in those terms. Research outcomes into how long-term memory is stored and retrieved provide support for structuring learning in this way. Four further messages are added to the…

  13. Who Recommends Long-Term Care Matters

    ERIC Educational Resources Information Center

    Kane, Robert L.; Bershadsky, Boris; Bershadsky, Julie

    2006-01-01

    Purpose: Making good consumer decisions requires having good information. This study compared long-term-care recommendations among various types of health professionals. Design and Methods: We gave randomly varied scenarios to a convenience national sample of 211 professionals from varying disciplines and work locations. For each scenario, we…

  14. Long-term lysimeter data on evapotranspiration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long term crop evapotranspiration (ET) data measured using large weighing lysimeters have only been gathered in a few places in the world, yet are of great importance for ground truthing of many models of plant water use, mesoscale climate, remote sensing estimation of ET, climate change and climate...

  15. Long-Term Impacts of Educational Interventions

    ERIC Educational Resources Information Center

    Deming, David James

    2010-01-01

    The school accountability movement has led to a marked increase in the use of standardized test scores to measure school and teacher productivity, yet little is known about the correlation between test score gains and improvements in long-term outcomes. In the first chapter of my dissertation, I study the impact of a school choice policy in…

  16. Long-Term Stability of Tutor Performance.

    ERIC Educational Resources Information Center

    Dolmans, Diana H. J. M.; And Others

    1996-01-01

    Examined the extent to which tutor ratings remained stable in the long term by evaluating 291 ratings of 140 tutors at Maastricht University in the Netherlands between 1992 and 1995. The results indicated that, if the aggregated score and overall judgement are used to interpret the precision of individual scores, four and two occasions,…

  17. Long-Term Stability of Social Participation

    ERIC Educational Resources Information Center

    Hyyppa, Markku T.; Maki, Juhani; Alanen, Erkki; Impivaara, Olli; Aromaa, Arpo

    2008-01-01

    The long-term stability of social participation was investigated in a representative urban population of 415 men and 579 women who had taken part in the nationwide Mini-Finland Health Survey in the years 1978-1980 and were re-examined 20 years later. Stability was assessed by means of the following tracking coefficients: kappa, proportion of…

  18. Long-term opioid therapy reconsidered.

    PubMed

    Von Korff, Michael; Kolodny, Andrew; Deyo, Richard A; Chou, Roger

    2011-09-06

    In the past 20 years, primary care physicians have greatly increased prescribing of long-term opioid therapy. However, the rise in opioid prescribing has outpaced the evidence regarding this practice. Increased opioid availability has been accompanied by an epidemic of opioid abuse and overdose. The rate of opioid addiction among patients receiving long-term opioid therapy remains unclear, but research suggests that opioid misuse is not rare. Recent studies report increased risks for serious adverse events, including fractures, cardiovascular events, and bowel obstruction, although further research on medical risks is needed. New data indicate that opioid-related risks may increase with dose. From a societal perspective, higher-dose regimens account for the majority of opioids dispensed, so cautious dosing may reduce both diversion potential and patient risks for adverse effects. Limiting long-term opioid therapy to patients for whom it provides decisive benefits could also reduce risks. Given the warning signs and knowledge gaps, greater caution and selectivity are needed in prescribing long-term opioid therapy. Until stronger evidence becomes available, clinicians should err on the side of caution when considering this treatment.

  19. Professionalism in Long-Term Care Settings

    ERIC Educational Resources Information Center

    Lubinski, Rosemary

    2006-01-01

    Speech-language pathologists who serve elders in a variety of long-term care settings have a variety of professional skills and responsibilities. Fundamental to quality service is knowledge of aging and communication changes and disorders associated with this process, institutional alternatives, and the changing nature of today's elders in…

  20. Long Term Care Aide. Course Outline.

    ERIC Educational Resources Information Center

    Wilbee, Judy

    This course outline is intended to assist the instructor in the development of a curriculum for a long-term care aide program by specifying one component of the curriculum--the objectives. These objectives, or competencies expected as outcomes for student performance on completion of the program, describe the capabilities an individual must…

  1. Evaluating Long-Term Disability Insurance Plans.

    ERIC Educational Resources Information Center

    Powell, Jan

    1992-01-01

    This report analyzes the factors involved in reviewing benefits and services of employer-sponsored group long-term disability plans for higher education institutions. Opening sections describe the evolution of disability insurance and its shape today. Further sections looks at the complex nature of "value" within a plan, relationship…

  2. LONG TERM HYDROLOGICAL IMPACT ASSESSMENT (LTHIA)

    EPA Science Inventory

    LTHIA is a universal Urban Sprawl analysis tool that is available to all at no charge through the Internet. It estimates impacts on runoff, recharge and nonpoint source pollution resulting from past or proposed land use changes. It gives long-term average annual runoff for a lan...

  3. Long-term fixed income market structure

    NASA Astrophysics Data System (ADS)

    Grilli, Luca

    2004-02-01

    Long-term fixed income market securities present a strong positive correlation in daily returns. By using a metrical approach and considering “modified” time series, I show how it is possible to show a more complex structure which depends strictly on the maturity date.

  4. Long-Term Care Research and Policy

    ERIC Educational Resources Information Center

    Kemper, Peter

    2003-01-01

    This article provides a framework for understanding how long-term care (LTC) research contributes to policy, develops a typology of research contributions to policy with examples of each type, and suggests ways to ensure that contributions continue in the future. The article draws on in-depth interviews with LTC experts working at the interface…

  5. Workshop on long-term contraceptives.

    PubMed

    1996-01-01

    The National Population Council Secretariat (NPCS) of Ghana held a three-day workshop on long-term contraceptives in 1996 in collaboration with the Ministry of Health, the Association of Voluntary Surgical Contraception, and the Johns Hopkins Population Communication Services. The session was funded by USAID. The executive director of NPCS, Dr. Richard Turkson, said that the slow rate of contraceptive acceptance was an obstacle to population control despite political concern that rapid population growth exerted an adverse impact on the economy. Only 10% of married women were using long-term or permanent methods of contraception. The hope was voiced that the participants would devise practical and cost-effective education, information, and communication (IEC) strategies to boost the demand for long-term contraceptive methods among sexually active people in Ghana. It was essential that these strategies and activities were based on a realist assessment of the demographic and social situation of the country. The examination of case studies in cultures similar to Ghana would also offer valuable lessons. The factors that hinder the acceptance of long-term methods include misconceptions, myths, and false rumors rooted in a general lack of knowledge among the people. Participants were urged to come up with strategies to counter these problems, and service providers were encouraged to improve their knowledge about contraceptive methods and counseling skills. Male involvement in contraception was also advocated. Statistics show that most Ghanians practicing contraception were using short-term methods such as foaming tablets, pills, and condoms. However, it is necessary to shift to long-term methods such as injectables, implants, and sterilization in order to achieve significant reductions in fertility.

  6. Long-term biological investigations in space.

    PubMed

    Lotz, R G; Fuchs, H; Bertsche, U

    1975-01-01

    Missions in space within the next two decades will be of longer duration than those carried out up to the present time, and the effects of such long-term flights on biological organisms are unknown. Results of biological experiments that have been performed to date cannot be extrapolated to results in future flights because of the unknown influence of adaptation over a long period of time. Prior experiments with Axolotl, fishes, and vertebrates by our research team (in part with sounding rockets) showed that these specimens did not appear to be suitable for long-term missions on which minimization of expense, technique, and energy is required. Subsequent investigations have shown the suitability of the leech (Hirudo medicinalis), which consumes blood of mammals up to ten times its own weight (1 g) and can live more than 2 years without further food supply. Emphasis in the experiments with Hirudo medicinalis is placed on metabolic rhythm and motility. Resorption and diffusion in tissue, development, and growth under long-term effects of cosmic proton radiation and zero-gravity are other focal points. The constancy of cellular life in the mature animals is a point in favor of these specimens. We have also taken into account the synergistic effects of the space environment on the problems just mentioned. The life-support system constructed for the leech has been tested successfully in four sounding rocket flights and, on that basis, has been prepared for a long-term mission. Long-term investigations out of the terrestrial biosphere will provide us with information concerning the degree of adaptation of certain physiological and biochemical functions and as to what extent biological readjustment or repair processes can occur under the specific stress conditions of space flight.

  7. Pulmonary complications after long term amiodarone treatment.

    PubMed Central

    Roca, J; Heras, M; Rodriguez-Roisin, R; Magriñà, J; Xaubet, A; Sanz, G

    1992-01-01

    BACKGROUND: Amiodarone hydrochloride is an antiarrhythmic agent useful in arrhythmias refractory to standard therapy. Although interstitial pneumonitis is known to be its most serious side effect, several aspects of amiodarone lung toxicity are still controversial. METHODS: Pulmonary side effects were examined in a sample of 61 symptomless patients (mean (SD) age 55 (7) years) who had had long term treatment with amiodarone (daily maintenance dose 400 mg), selected from 482 men attending the University of Barcelona myocardial infarction project. To allow for the confounding effects of coronary artery disease and tobacco history on lung function, 46 patients who had taken amiodarone for more than one year were matched with a control group from the same population. Subjects underwent measurement of lung volumes, arterial blood gas analysis and an incremental bicycle exercise test. RESULTS: Most lung function values were close to predicted values, though there was a small increase in resting alveolar-arterial oxygen tension difference (A-aDO2) at rest (4.8 (1.4) kPa in both groups). There were no differences in the results of forced spirometry or static lung volumes between the two groups, or in the fall in A-aDO2 from rest to exercise. There was a small difference between the amiodarone and the control group in transfer factor for carbon monoxide corrected for lung volume (KCO 1.67 (0.3) and 1.83 (0.3) mmol min-1 kPa-1 l-1 respectively) and in exercise capacity (140 (25) and 120 (30)w). Only three patients showed lung function impairment consistent with pneumonitis. No relation between lung function measures and cumulative doses of amiodarone or desethylamiodarone was found. CONCLUSIONS: The prevalence of clinically evident pulmonary side effects was 4.9%, which is lower than that reported in studies in which higher daily maintenance doses of amiodarone were given. The slightly lower KCO values and lower work load achieved by the patients taking amiodarone suggest a

  8. Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system. Volume 3, phase 3: Full size heat shield data correlation and design criteria. [reentry

    NASA Technical Reports Server (NTRS)

    Cramer, B. A.; Davis, J. W.

    1975-01-01

    Analysis methods for predicting cyclic creep deflection in stiffened metal panel structures, were applied to full size panels. Results were compared with measured deflections from cyclic tests of thin gage L605, Rene' 41, and TDNiCr full size corrugation stiffened panels. A design criteria was then formulated for metallic thermal protection panels subjected to creep. A computer program was developed to calculate creep deflections.

  9. Phase transformation and long-term service of high-temperature martensitic chromium steels

    NASA Astrophysics Data System (ADS)

    Kalashnikov, I. S.; Tarasenko, L.; Acselrad, O.; Pereira, L. C.; Shalkevich, A.; Soboleva, G.

    2000-02-01

    Martensitic high Cr (10 - 16%) steels alloyed with Ni (Co), Mo, W, V, and N are widely used in constructions subjected to cyclic loads at temperatures up to 600 degrees Celsius, in general after quenching from 1100 - 1150 degrees Celsius followed by tempering at 650 - 690 degrees Celsius. Due to long term service exposure at high temperatures, different microstructural changes take place, such as second-phases precipitation, formation of low-angle grain boundaries, as well as internal damage caused by cyclic loads and creep. Specific phase diagrams are presented that can be used to define time periods for reliable operation of parts with given composition, based on the time required for the appearance of second phase particles known to be detrimental to mechanical strength and performance. Restoring thermal treatments to be applied after long time exposure at service conditions, aiming at increasing service life, are also presented and discussed. The combined use of the diagrams and the restoring treatment ensures prediction of a reliable service-life period for components made of these steels.

  10. Phase transformation and long-term service of high-temperature martensitic chromium steels

    NASA Astrophysics Data System (ADS)

    Kalashnikov, I. S.; Tarasenko, L.; Acselrad, O.; Pereira, L. C.; Shalkevich, A.; Soboleva, G.

    2001-02-01

    Martensitic high Cr (10 - 16%) steels alloyed with Ni (Co), Mo, W, V, and N are widely used in constructions subjected to cyclic loads at temperatures up to 600 degrees Celsius, in general after quenching from 1100 - 1150 degrees Celsius followed by tempering at 650 - 690 degrees Celsius. Due to long term service exposure at high temperatures, different microstructural changes take place, such as second-phases precipitation, formation of low-angle grain boundaries, as well as internal damage caused by cyclic loads and creep. Specific phase diagrams are presented that can be used to define time periods for reliable operation of parts with given composition, based on the time required for the appearance of second phase particles known to be detrimental to mechanical strength and performance. Restoring thermal treatments to be applied after long time exposure at service conditions, aiming at increasing service life, are also presented and discussed. The combined use of the diagrams and the restoring treatment ensures prediction of a reliable service-life period for components made of these steels.

  11. Experimental Study on Creep Characterization and Lifetime Estimation of RPV Material at 723-1023 K

    NASA Astrophysics Data System (ADS)

    Xie, Lin-Jun; Ning, Dong; Yang, Yi-zhong

    2017-01-01

    During the plant operation, nuclear reactor pressure vessel (RPV) is the most critical pressure boundary component for integrity and safety in a light-water reactor. In this paper, the creep behavior and properties for RPV metallic material are studied by conducting constant-temperature and constant-load creep tests at 723, 823, 923 and 1023 K. The θ projection constitutive model was established based on a creep method to describe the high-temperature creep behavior of RPV material. The material parameter θ would be obtained based on experimental data by depending on numerical optimization techniques. The relationship between and among θ, T and σ was evaluated, and the coefficients a i , b i , c i and d i were obtained. Based on the short-term tests at a high temperature, the values for long-term creep data could be predicted in accordance with parameter θ. Moreover, rupture life, the minimum creep rate and the time reaching to an arbitrary strain can be calculated and may be used to evaluate the damage behavior and properties, so as to be used as a reference for design and safety assessment.

  12. Microstructures and Type-IV Creep Damage of High Cr Steel Welds

    NASA Astrophysics Data System (ADS)

    Hongo, Hiromichi; Tabuchi, Masaaki; Takahashi, Yukio

    Creep strength of welded joints in high Cr steels decreases due to the formation of Type-IV creep damage in the heat-affected zone (HAZ) during long-term use at high temperatures. This paper aims to elucidate the processes and mechanisms of Type-IV failure. Creep tests for the welded joints with different groove configurations of Mod.9Cr-1Mo steel were conducted. Distributions of Type-IV creep damages in HAZ of these welds were measured quantitatively, and were compared with FEM computations using damage mechanics analysis. For the welded joints with double U groove, creep voids were observed mostly at 20% below the surface of the plate, and scarcely near surfaces and center of thickness. For the welded joints with single U groove, creep voids were observed inside the plate thickness more than 3mm below the surfaces. From the comparison of experimental damage distributions with FEM analysis, it is considered to be important to take the stress triaxiality into account for the prediction of damage location and fracture life of high Cr ferritic steel welds.

  13. Experimental Study on Creep Characterization and Lifetime Estimation of RPV Material at 723-1023 K

    NASA Astrophysics Data System (ADS)

    Xie, Lin-Jun; Ning, Dong; Yang, Yi-zhong

    2017-02-01

    During the plant operation, nuclear reactor pressure vessel (RPV) is the most critical pressure boundary component for integrity and safety in a light-water reactor. In this paper, the creep behavior and properties for RPV metallic material are studied by conducting constant-temperature and constant-load creep tests at 723, 823, 923 and 1023 K. The θ projection constitutive model was established based on a creep method to describe the high-temperature creep behavior of RPV material. The material parameter θ would be obtained based on experimental data by depending on numerical optimization techniques. The relationship between and among θ, T and σ was evaluated, and the coefficients a i , b i , c i and d i were obtained. Based on the short-term tests at a high temperature, the values for long-term creep data could be predicted in accordance with parameter θ. Moreover, rupture life, the minimum creep rate and the time reaching to an arbitrary strain can be calculated and may be used to evaluate the damage behavior and properties, so as to be used as a reference for design and safety assessment.

  14. Case presentation: long-term treatment.

    PubMed

    Glucksman, Myron L

    2013-01-01

    The long-term (14 years) psychodynamic psychotherapy and pharmacotherapy of a depressed, suicidal, self-mutilating female patient is described. Her diagnoses included Chronic Posttraumatic Stress Disorder, Borderline Personality Disorder, and Recurrent Major Depression. Treatment was punctuated with repeated hospitalizations for self-mutilation (cutting) and suicidal ideation. A major determinant for her psychopathology was sexual abuse by her father from ages 6 to 14. This resulted in feelings of guilt and rage that she repressed and acted out through self-mutilating and suicidal behavior. A prolonged negative transference gradually became ambivalent, then positive. This was associated with her internalization of the healing qualities of the therapeutic relationship. She also gained insight into the reasons for her need to punish herself. Her initial self-representation as unworthy and bad was transformed into perceiving herself as a worthwhile, loving person. This case illustrates the role of long-term treatment for a complex, life-threatening, psychiatric disorder.

  15. Irradiation Creep in Graphite

    SciTech Connect

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  16. Long-term sequelae of electrical injury

    PubMed Central

    Wesner, Marni L.; Hickie, John

    2013-01-01

    Abstract Objective To summarize the current evidence-based knowledge about the long-term sequelae of injuries from electrical current. Quality of evidence MEDLINE was searched for English-language articles published in the past 20 years using the following search terms: electrical, injuries, wound, trauma, accident, sequelae, long-term, follow-up, and aftereffects. For obvious reasons, it is unethical to randomly study electrical injury in controlled clinical trials. By necessity, this topic is addressed in less-rigorous observational and retrospective work and case studies. Therefore, the strength of the literature pertaining to the long-term sequelae of electrical injury is impaired by the necessity of retrospective methods and case studies that typically describe small cohorts. Main message There are 2 possible consequences of electrical injury: the person either survives or dies. For those who survive electrical injury, the immediate consequences are usually obvious and often require extensive medical intervention. The long-term sequelae of the electrical injury might be more subtle, pervasive, and less well defined, but can include neurologic, psychological, and physical symptoms. In the field of compensation medicine, determining causation and attributing outcome to an injury that might not result in objective clinical findings becomes a considerable challenge. Conclusion The appearance of these consequences of electrical injury might be substantially delayed, with onset 1 to 5 or more years after the electrical injury. This poses a problem for patients and health care workers, making it hard to ascribe symptoms to a remote injury when they might not arise until well after the incident event. PMID:24029506

  17. Long-term course of opioid addiction.

    PubMed

    Hser, Yih-Ing; Evans, Elizabeth; Grella, Christine; Ling, Walter; Anglin, Douglas

    2015-01-01

    Opioid addiction is associated with excess mortality, morbidities, and other adverse conditions. Guided by a life-course framework, we review the literature on the long-term course of opioid addiction in terms of use trajectories, transitions, and turning points, as well as other factors that facilitate recovery from addiction. Most long-term follow-up studies are based on heroin addicts recruited from treatment settings (mostly methadone maintenance treatment), many of whom are referred by the criminal justice system. Cumulative evidence indicates that opioid addiction is a chronic disorder with frequent relapses. Longer treatment retention is associated with a greater likelihood of abstinence, whereas incarceration is negatively related to subsequent abstinence. Over the long term, the mortality rate of opioid addicts (overdose being the most common cause) is about 6 to 20 times greater than that of the general population; among those who remain alive, the prevalence of stable abstinence from opioid use is low (less than 30% after 10-30 years of observation), and many continue to use alcohol and other drugs after ceasing to use opioids. Histories of sexual or physical abuse and comorbid mental disorders are associated with the persistence of opioid use, whereas family and social support, as well as employment, facilitates recovery. Maintaining opioid abstinence for at least five years substantially increases the likelihood of future stable abstinence. Recent advances in pharmacological treatment options (buprenorphine and naltrexone) include depot formulations offering longer duration of medication; their impact on the long-term course of opioid addiction remains to be assessed.

  18. Breakthroughs in long term care design.

    PubMed

    Hiatt, L

    1991-01-01

    In summary, here is what design is trying to accomplish in long term care facilities: Functional access; Privacy as entitlement; Sensory optimization to improve vision and hearing; Reduced walking and wheeling distances that still allow people to be mobile; Effective or functional placement of space and equipment; The option of smaller scale, so neither residents nor staff feel like they are hanging out with a unit full of, perhaps 68, people all the time; Flexibility and adaptability

  19. Electrodes for long-term esophageal electrocardiography.

    PubMed

    Niederhauser, Thomas; Haeberlin, Andreas; Marisa, Thanks; Jungo, Michael; Goette, Josef; Jacomet, Marcel; Abacherli, Roger; Vogel, Rolf

    2013-09-01

    The emerging application of long-term and high-quality ECG recording requires alternative electrodes to improve the signal quality and recording capability of surface skin electrodes. The esophageal ECG has the potential to overcome these limitations but necessitates novel recorder and lead designs. The electrode material is of particular interest, since the material has to ensure conflicting requirements like excellent biopotential recording properties and inertness. To this end, novel electrode materials like PEDOT and silver-PDMS as well as established electrode materials such as stainless steel, platinum, gold, iridium oxide, titanium nitride, and glassy carbon were investigated by long-term electrochemical impedance spectroscopy and model-based signal analysis using the derived in vitro interfacial properties in conjunction with a dedicated ECG amplifier. The results of this novel approach show that titanium nitride and iridium oxide featuring microstructured surfaces did not degrade when exposed to artificial acidic saliva. These materials provide low electrode potential drifts and insignificant signal distortion superior to surface skin electrodes making them compatible with accepted standards for ambulatory ECG. They are superior to the noble and polarizable metals such as platinum, silver, and gold that induced more signal distortions and are superior to esophageal stainless steel electrodes that corrode in artificial saliva. The study provides rigorous criteria for the selection of electrode materials for prolonged ECG recording by combining long-term in vitro electrode material properties with ECG signal quality assessment.

  20. Long term therapy of generalized anxiety disorder.

    PubMed

    Rouillon, Frédéric

    2004-04-01

    Generalized anxiety disorder (GAD) is a common (lifetime prevalence: 5.1%), recurrent condition, which often heralds other psychiatric disorders, notably depression. As by definition it is a disorder progressing over months, treatment should be designed on a long term basis. And yet, few studies have been conducted beyond the classical 6-8 weeks characterizing the acute treatment phase. This is especially true of anxiolytics, but also of antidepressants, with the exception of paroxetine and venlafaxine, which are the only drugs approved in this indication in Western countries. The efficacy of psychotherapy, notably relaxation and cognitive-behavioral therapy, is established in the treatment of GAD, but its preferred indications and possible combination with antidepressants are still to be specified. Long term, not to say very long term studies of GAD, as well as depression, will still be required in the future to improve its management and specify therapeutic modalities (combination treatment, optimal duration, continuous or intermittent therapy, choice of psychotherapeutic techniques or agents, em leader ). Early and adequately prolonged treatment should not only result in more numerous remission periods, but also in decreased frequency of co-morbidities whether depressive, addictive, or of another nature, and should also reduce the social impact of GAD.

  1. Titanium for long-term tritium storage

    SciTech Connect

    Heung, L.K.

    1994-12-01

    Due to the reduction of nuclear weapon stockpile, there will be an excess of tritium returned from the field. The excess tritium needs to be stored for future use, which might be several years away. A safe and cost effective means for long term storage of tritium is needed. Storing tritium in a solid metal tritide is preferred to storing tritium as a gas, because a metal tritide can store tritium in a compact form and the stored tritium will not be released until heat is applied to increase its temperature to several hundred degrees centigrade. Storing tritium as a tritide is safer and more cost effective than as a gas. Several candidate metal hydride materials have been evaluated for long term tritium storage. They include uranium, La-Ni-Al alloys, zirconium and titanium. The criteria used include material cost, radioactivity, stability to air, storage capacity, storage pressure, loading and unloading conditions, and helium retention. Titanium has the best combination of properties and is recommended for long term tritium storage.

  2. Business Students' Choice of Short-Term or Long-Term Study Abroad Opportunities

    ERIC Educational Resources Information Center

    Fitzsimmons, Stacey R.; Flanagan, David J.; Wang, Xiaodan

    2013-01-01

    Recent years have seen a proliferation of short-term study abroad opportunities. Although they are both supplementing and replacing semester-long study abroad programs, research has focused primarily on semester (long-term) programs. We draw on the theory of planned behavior (TPB) to explore factors that predict why students choose long-term and…

  3. The Parable of the Sower and the Long-Term Effects of Early Reading

    ERIC Educational Resources Information Center

    Suggate, Sebastian P.

    2015-01-01

    Previous work on the long-term effects of early reading focuses on whether children can read early (i.e. capability) not on whether this is beneficial (i.e. optimality). The Luke Effect is introduced to predict long-term reading development as a function of when children learn to read. A review of correlational, intervention, and comparative…

  4. Short and Long-Term Outcomes for Extremely Preterm Infants

    PubMed Central

    Patel, Ravi Mangal

    2016-01-01

    Prematurity is the leading cause of infant mortality worldwide. In developed countries, extremely preterm infants contribute disproportionately to both neonatal and infant mortality. Survival of this high-risk population has incrementally improved in recent years. Despite these improvements, approximately 1 in 4 extremely preterm infants dies during the birth hospitalization. Among those who survive, respiratory and other morbidities are common, although their effect on quality of life is variable. In addition, long-term neurodevelopmental impairment is a large concern for patients, clinicians and families. However, the interplay of multiple factors contribute to neurodevelopmental impairment, with measures that change over time and outcomes that can be difficult to define and predict. Understanding outcomes of extremely preterm infants can help better counsel families regarding antenatal and postnatal care and guide strategies to improve survival without morbidity. This review summarizes recent evidence to provide an overview into the short- and long-term outcomes for extremely preterm infants. PMID:26799967

  5. Tertiary creep test by ring shear apparatus in predicting initiation time of rainfall-induced-shallow landslide

    NASA Astrophysics Data System (ADS)

    Dok, A.; Fukuoka, H.

    2010-12-01

    Landslides are complex geo-disaters that frequently occur due to certain causes, but only one trigger such as earthquake or heavy rainfall or other related natural phenomenas. A slope failure seldom occurs without any creep deformation. Failure time of a slope as found by Fukuzono (1985) and Siato (1965) based on graphical analysis of extensometer monitoring data through large scale flume test for landslide studies, logarithm of acceleration is proportional to the logarithm of velocity of surface displacement immediately before the failure. It is expressed as d2x/dt2 = A(dx/dt)α, where x is surface displacement, t is time, and A and α are constant. And, Fukuzono (1985, 1989) proposed a simple method of predicting the time of falure by the inverse velocity (1/v) mean. The curve of inverse velocity is concave at 1< α<2, linear at α=2, and convex at α>2. Recently, Minamitani (2007) have researched on mechanism of Tertiary Creep deformation for landslide failure time prediction by increasing shear-stress development in order to understand the story behind the empirical relationship found by senior researcher Fukozono. He found a strong relationshp between constants A and α, expressed as α = 0.1781A+ 1.814. For deeper understanding, this study aims at learning in more detail on mechanism of landslides in tropical soils by ring shear apparatus (invented by DPRI, Disaster Prevention Research Institute) based on Tertiary Creep deformation theory in help issue warning on rainfall-induced landslides through back (pore-water) pressure control tests under combined conditions of particular normal stress and shear stress with pore-water pressure changes to simulate the potential sliding surface condition in the heavy rainfall, which no body experiences conducting such a test series, particularly by applying cyclic and actual groundwater change pattern to the soils. To reach the archivement, serie of back pressure control test were implemented by utilising stress

  6. A Comparison of Tension and Compression Creep in a Polymeric Composite and the Effects of Physical Aging on Creep Behavior

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Veazie, David R.; Brinson, L. Catherine

    1996-01-01

    Experimental and analytical methods were used to investigate the similarities and differences of the effects of physical aging on creep compliance of IM7/K3B composite loaded in tension and compression. Two matrix dominated loading modes, shear and transverse, were investigated for two load cases, tension and compression. The tests, run over a range of sub-glass transition temperatures, provided material constants, material master curves and aging related parameters. Comparing results from the short-term data indicated that although trends in the data with respect to aging time and aging temperature are similar, differences exist due to load direction and mode. The analytical model used for predicting long-term behavior using short-term data as input worked equally as well for the tension or compression loaded cases. Comparison of the loading modes indicated that the predictive model provided more accurate long term predictions for the shear mode as compared to the transverse mode. Parametric studies showed the usefulness of the predictive model as a tool for investigating long-term performance and compliance acceleration due to temperature.

  7. Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Teactor Pressure Vessels

    SciTech Connect

    Potirniche, Gabriel; Barlow, Fred D.; Charit, Indrajit; Rink, Karl

    2013-11-26

    A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions; Perform creep tests and characterize the mechanisms of creep fracture process; Quantify how the microstructure degradation controls the creep strength of welded steel specimens; Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds; Develop a microstructure-based creep fracture model to estimate RPVs service life; Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates; Simulate damage evolution in creep specimens by FE analyses; Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage; Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength; Develop a fracture model for the structural integrity of RPVs subjected to creep loads; and Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

  8. Brief summary of the evolution of high-temperature creep-fatigue life prediction models for crack initiation

    NASA Astrophysics Data System (ADS)

    Halford, Gary R.

    1993-10-01

    The evolution of high-temperature, creep-fatigue, life-prediction methods used for cyclic crack initiation is traced from inception in the late 1940's. The methods reviewed are material models as opposed to structural life prediction models. Material life models are used by both structural durability analysts and by material scientists. The latter use micromechanistic models as guidance to improve a material's crack initiation resistance. Nearly one hundred approaches and their variations have been proposed to date. This proliferation poses a problem in deciding which method is most appropriate for a given application. Approaches were identified as being combinations of thirteen different classifications. This review is intended to aid both developers and users of high-temperature fatigue life prediction methods by providing a background from which choices can be made. The need for high-temperature, fatigue-life prediction methods followed immediately on the heels of the development of large, costly, high-technology industrial and aerospace equipment immediately following the second world war. Major advances were made in the design and manufacture of high-temperature, high-pressure boilers and steam turbines, nuclear reactors, high-temperature forming dies, high-performance poppet valves, aeronautical gas turbine engines, reusable rocket engines, etc. These advances could no longer be accomplished simply by trial and error using the 'build-em and bust-em' approach. Development lead times were too great and costs too prohibitive to retain such an approach. Analytic assessments of anticipated performance, cost, and durability were introduced to cut costs and shorten lead times. The analytic tools were quite primitive at first and out of necessity evolved in parallel with hardware development. After forty years more descriptive, more accurate, and more efficient analytic tools are being developed. These include thermal-structural finite element and boundary element

  9. Brief summary of the evolution of high-temperature creep-fatigue life prediction models for crack initiation

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.

    1993-01-01

    The evolution of high-temperature, creep-fatigue, life-prediction methods used for cyclic crack initiation is traced from inception in the late 1940's. The methods reviewed are material models as opposed to structural life prediction models. Material life models are used by both structural durability analysts and by material scientists. The latter use micromechanistic models as guidance to improve a material's crack initiation resistance. Nearly one hundred approaches and their variations have been proposed to date. This proliferation poses a problem in deciding which method is most appropriate for a given application. Approaches were identified as being combinations of thirteen different classifications. This review is intended to aid both developers and users of high-temperature fatigue life prediction methods by providing a background from which choices can be made. The need for high-temperature, fatigue-life prediction methods followed immediately on the heels of the development of large, costly, high-technology industrial and aerospace equipment immediately following the second world war. Major advances were made in the design and manufacture of high-temperature, high-pressure boilers and steam turbines, nuclear reactors, high-temperature forming dies, high-performance poppet valves, aeronautical gas turbine engines, reusable rocket engines, etc. These advances could no longer be accomplished simply by trial and error using the 'build-em and bust-em' approach. Development lead times were too great and costs too prohibitive to retain such an approach. Analytic assessments of anticipated performance, cost, and durability were introduced to cut costs and shorten lead times. The analytic tools were quite primitive at first and out of necessity evolved in parallel with hardware development. After forty years more descriptive, more accurate, and more efficient analytic tools are being developed. These include thermal-structural finite element and boundary element

  10. Creep and creep-rupture behavior of Alloy 718

    SciTech Connect

    Brinkman, C.R.; Booker, M.K.; Ding, J.L.

    1991-01-01

    Data obtained from creep and creep-rupture tests conducted on 18 heats of Alloy 718 were used to formulate models for predicting high temperature time dependent behavior of this alloy. Creep tests were conducted on specimens taken from a number of commercial product forms including plate, bar, and forgoing material that had been procured and heat treated in accordance with ASTM specifications B-670 or B-637. Data were obtained over the temperature range of 427 to 760{degree}C ad at test times to about 87,000 h. Comparisons are given between experimental data and the analytical models. The analytical models for creep-rupture included one based on lot-centering regression analysis and two based on the Minimum Commitment Method. A master'' curve approach was used to develop and equation for estimating creep deformation up to the onset of tertiary creep. 11 refs., 13 figs.

  11. Long-Term Monitoring Research Needs: A DOE Perspective

    NASA Astrophysics Data System (ADS)

    Moore, B.; Davis, C. B.

    2002-05-01

    critically on the validity and uncertainty in models used to predict contaminant fate and transport. This is an area of active research at the present time. We survey joint research initiatives in this area involving DOE along with USGS, U.S. EPA, U.S. NRC, and U.S. DOA and non-Federal collaborators, and explore their potential for furthering DOE long-term monitoring needs and objectives.

  12. Long-Term Wind Power Variability

    SciTech Connect

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  13. Transverse dimension and long-term stability.

    PubMed

    Vanarsdall, R L

    1999-09-01

    This article emphasizes the critical importance of the skeletal differential between the width of the maxilla and the width of the mandible. Undiagnosed transverse discrepancy leads to adverse periodontal response, unstable dental camouflage, and less than optimal dentofacial esthetics. Hundreds of adult retreatment patients corrected for significant maxillary transverse deficiency using surgically assisted maxillary expansion (similar to osseous distraction) has produced excellent stability. Eliciting tooth movement for children (orthopedics, lip bumper, Cetlin plate) in all three planes of space by muscles, eruption, and growth, develops the broader arch form (without the mechanical forces of fixed or removable appliances) and has also demonstrated impressive long term stability.

  14. Long-term management of prolactinomas.

    PubMed

    Schlechte, Janet A

    2007-08-01

    Prolactinomas are a frequent cause of gonadal dysfunction and infertility, especially in young women. The regulation of prolactin secretion and the efficacy of dopamine agonists in the therapy of prolactinomas are well established. The current challenges in management of prolactinomas are related to follow-up after successful therapy. Issues and questions to be addressed in this approach to long-term management of prolactinomas include the frequency of radiographic monitoring, effect of pregnancy and menopause, safety of estrogen in women taking oral contraceptives, and the potential for discontinuation of dopamine agonist therapy.

  15. Human Behaviour in Long-Term Missions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session WP1, the discussion focuses on the following topics: Psychological Support for International Space Station Mission; Psycho-social Training for Man in Space; Study of the Physiological Adaptation of the Crew During A 135-Day Space Simulation; Interpersonal Relationships in Space Simulation, The Long-Term Bed Rest in Head-Down Tilt Position; Psychological Adaptation in Groups of Varying Sizes and Environments; Deviance Among Expeditioners, Defining the Off-Nominal Act in Space and Polar Field Analogs; Getting Effective Sleep in the Space-Station Environment; Human Sleep and Circadian Rhythms are Altered During Spaceflight; and Methodological Approach to Study of Cosmonauts Errors and Its Instrumental Support.

  16. Long-term forecasting of internet backbone traffic.

    PubMed

    Papagiannaki, Konstantina; Taft, Nina; Zhang, Zhi-Li; Diot, Christophe

    2005-09-01

    We introduce a methodology to predict when and where link additions/upgrades have to take place in an Internet protocol (IP) backbone network. Using simple network management protocol (SNMP) statistics, collected continuously since 1999, we compute aggregate demand between any two adjacent points of presence (PoPs) and look at its evolution at time scales larger than 1 h. We show that IP backbone traffic exhibits visible long term trends, strong periodicities, and variability at multiple time scales. Our methodology relies on the wavelet multiresolution analysis (MRA) and linear time series models. Using wavelet MRA, we smooth the collected measurements until we identify the overall long-term trend. The fluctuations around the obtained trend are further analyzed at multiple time scales. We show that the largest amount of variability in the original signal is due to its fluctuations at the 12-h time scale. We model inter-PoP aggregate demand as a multiple linear regression model, consisting of the two identified components. We show that this model accounts for 98% of the total energy in the original signal, while explaining 90% of its variance. Weekly approximations of those components can be accurately modeled with low-order autoregressive integrated moving average (ARIMA) models. We show that forecasting the long term trend and the fluctuations of the traffic at the 12-h time scale yields accurate estimates for at least 6 months in the future.

  17. Teen motherhood and long-term health consequences.

    PubMed

    Patel, Payal H; Sen, Bisakha

    2012-07-01

    The objective of this article is to examine the association of teen motherhood and long-term physical and mental health outcomes. The physical and mental health components (PCS and MCS) of the SF-12 Healthy Survey in the NLSY79 health module were used to assess long-term health outcomes of women who experienced teenage motherhood. Various familial, demographic, and environmental characteristics were indentified and controlled for that may have predicted teen motherhood and long-term health outcomes. The two comparison groups for teen mothers were women who experienced teen-pregnancy only and women who were engaged in unprotected sexual activity as a teenage but did not experience pregnancy. Multivariate ordinary least squares regression was used for analysis. The average PCS and MCS for teen mothers was 49.91 and 50.89, respectively. Teen mothers exhibited poorer physical health later in life compared to all women as well as the comparison groups. When controlling for age, teen mothers had significantly lower PCS and MCS scores compared to all other women. Furthermore, when controlling for familial, demographic, and environmental characteristics, teen mothers exhibited significantly lower PCS and MCS scores. When comparing teen mothers to the two comparison groups, PCS was not statistically different although MCS was significantly lower in the teen-pregnancy group. Teen motherhood does lead to poorer physical health outcomes later in life. On the other hand, poorer mental health outcomes in later life may be attributed to the unmeasured factors leading to a teen pregnancy and not teen motherhood itself. Additional research needs to be conducted on the long-term consequences of teen motherhood.

  18. Principles of Long-Term Dynamics of Dendritic Spines

    PubMed Central

    Yasumatsu, Nobuaki; Matsuzaki, Masanori; Miyazaki, Takashi; Noguchi, Jun; Kasai, Haruo

    2008-01-01

    Long-term potentiation (LTP) of synapse strength requires enlargement of dendritic spines on cerebral pyramidal neurons. Long-term depression (LTD) is linked to spine shrinkage. Indeed, spines are dynamic structures: they form, change their shapes and volumes or can disappear in the space of hours. Do all such changes result from synaptic activity, or do some changes result from intrinsic processes? How do enlargement and shrinkage of spines relate to elimination and generation of spines, and how do these processes contribute to the stationary distribution of spine volumes? To answer these questions, we recorded the volumes of many individual spines daily for several days using two-photon imaging of CA1 pyramidal neurons in cultured slices of rat hippocampus between postnatal day 17 to 23. With normal synaptic transmission, spines often changed volume or were created or eliminated, thereby showing activity-dependent plasticity. However, we found that spines changed volume even after we blocked synaptic activity, reflecting a native instability of these small structures over the long term. Such “intrinsic fluctuations” showed unique dependence on spine volume. A mathematical model constructed from these data and the theory of random fluctuations explains population behaviors of spines, such as rates of elimination and generation, stationary distribution of volumes and the long-term persistence of large spines. Our study finds that generation and elimination of spines are more prevalent than previously believed, and spine volume shows significant correlation with its age and life expectancy. The population dynamics of spines also predict key psychological features of memory. PMID:19074033

  19. Long term efficacy of a pen injector.

    PubMed

    Dinneen, S F; Cronin, C C; O'Sullivan, D J

    1991-09-01

    We assessed the long term efficacy of Novopen as a form of insulin administration. Records were obtained on 48 patients who were treated with Novopen between January '86 and October '88. Six patients were excluded due to insufficient data. The study group of 42 patients comprised 22 females and 20 males of average age 33 years (range 17-66). Mean Hb.A1 rose from 10.6% to 12.1% after Novopen therapy, a rise of 14.1%. This rise is both clinically and statistically significant (p less than 0.001; 99% confidence limits 0.59-2.78). Increases in weight and insulin dose were also noted, but did not reach statistical significance. The majority of patients felt Novopen was superior to twice daily insulin in terms of ease of administration (81%) and flexibility of lifestyle (95%), and all who were using Novopen wished to continue with it. More than 50% of patients admitted to altering their dietary habits while using Novopen. Despite continuing patient satisfaction with this form of insulin administration, its long-term use may be associated with sub-optimal metabolic control.

  20. Craniopharyngioma in Children: Long-term Outcomes

    PubMed Central

    STEINBOK, Paul

    2015-01-01

    The survival rate for childhood craniopharyngioma has been improving, with more long-term survivors. Unfortunately it is rare for the patient to be normal, either from the disease itself or from the effects of treatment. Long-term survivors of childhood craniopharyngioma suffer a number of impairments, which include visual loss, endocrinopathy, hypothalamic dysfunction, cerebrovascular problems, neurologic and neurocognitive dysfunction. Pituitary insufficiency is present in almost 100%. Visual and hypothalamic dysfunction is common. There is a high risk of metabolic syndrome and increased risk of cerebrovascular disease, including stroke and Moyamoya syndrome. Cognitive, psychosocial, and emotional problems are prevalent. Finally, there is a higher risk of premature death among survivors of craniopharyngioma, and often this is not from tumor recurrence. It is important to consider craniopharyngioma as a chronic disease. There is no perfect treatment. The treatment has to be tailored to the individual patient to minimize dysfunction caused by tumor and treatments. So “cure” of the tumor does not mean a normal patient. The management of the patient and family needs multidisciplinary evaluation and should involve ophthalmology, endocrinology, neurosurgery, oncology, and psychology. Furthermore, it is also important to address emotional issues and social integration. PMID:26345668

  1. Long-Term Care Policy: Singapore's Experience.

    PubMed

    Chin, Chee Wei Winston; Phua, Kai-Hong

    2016-01-01

    Singapore, like many developed countries, is facing the challenge of a rapidly aging population and the increasing need to provide long-term care (LTC) services for elderly in the community. The Singapore government's philosophy on care for the elderly is that the family should be the first line of support, and it has relied on voluntary welfare organizations (VWOs) or charities for the bulk of LTC service provision. For LTC financing, it has emphasized the principles of co-payment and targeting of state support to the low-income population through means-tested government subsidies. It has also instituted ElderShield, a national severe disability insurance scheme. This paper discusses some of the challenges facing LTC policy in Singapore, particularly the presence of perverse financial incentives for hospitalization, the pitfalls of over-reliance on VWOs, and the challenges facing informal family caregivers. It discusses the role of private LTC insurance in LTC financing, bearing in mind demand- and supply-side failures that have plagued the private LTC insurance market. It suggests the need for more standardized needs assessment and portable LTC benefits, with reference to the Japanese Long-Term Care Insurance program, and also discusses the need to provide more support to informal family caregivers.

  2. Long term perfusion system supporting adipogenesis

    PubMed Central

    Abbott, Rosalyn D.; Raja, Waseem K.; Wang, Rebecca Y.; Stinson, Jordan A.; Glettig, Dean L.; Burke, Kelly A.; Kaplan, David L.

    2015-01-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogensis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  3. Long-term experience with indapamide.

    PubMed

    Beling, S; Vukovich, R A; Neiss, E S; Zisblatt, M; Webb, E; Losi, M

    1983-07-01

    Indapamide, 2.5 mg administered once daily for periods up to 36 months, was found to be safe and effective for the long-term control of mild to moderate hypertension. The effects of hydrochlorothiazide, 50 mg, and indapamide, 2.5 mg, were studied in two randomized, double-blind, multicenter trials. Data from the two multicenter trials (20 study sites) were pooled for purposes of comparison. Significant reductions in systolic and diastolic blood pressure, with patients in both supine and standing positions, occurred in both groups within the first 8 weeks of treatment. This effect was maintained throughout the active treatment period. Success, as determined by the therapeutic success rate (percentage of patients with decreases of standing phase V diastolic blood pressure of at least 10 mm Hg or to below 90 mm Hg), occurred in 53% of the patients given hydrochlorothiazide and in 56% of the indapamide-treated patients. During the study period, the nature, frequency, and severity of adverse reactions were similar for both groups. There was no clinically significant difference between the treatment groups for the laboratory assessments. Patients who completed the multicenter trials were eligible for participation in an ongoing long-term extension study of the safety of indapamide. Data are available for periods up to 36 months and demonstrate neither augmentation of clinical or laboratory adverse effects nor any potentially harmful indicators that could be attributed to prolonged treatment.

  4. Clinical review: Long-term noninvasive ventilation

    PubMed Central

    Robert, Dominique; Argaud, Laurent

    2007-01-01

    Noninvasive positive ventilation has undergone a remarkable evolution over the past decades and is assuming an important role in the management of both acute and chronic respiratory failure. Long-term ventilatory support should be considered a standard of care to treat selected patients following an intensive care unit (ICU) stay. In this setting, appropriate use of noninvasive ventilation can be expected to improve patient outcomes, reduce ICU admission, enhance patient comfort, and increase the efficiency of health care resource utilization. Current literature indicates that noninvasive ventilation improves and stabilizes the clinical course of many patients with chronic ventilatory failure. Noninvasive ventilation also permits long-term mechanical ventilation to be an acceptable option for patients who otherwise would not have been treated if tracheostomy were the only alternative. Nevertheless, these results appear to be better in patients with neuromuscular/-parietal disorders than in chronic obstructive pulmonary disease. This clinical review will address the use of noninvasive ventilation (not including continuous positive airway pressure) mainly in diseases responsible for chronic hypoventilation (that is, restrictive disorders, including neuromuscular disease and lung disease) and incidentally in others such as obstructive sleep apnea or problems of central drive. PMID:17419882

  5. Long term changes in the polar vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.

  6. Long Term Changes in the Polar Vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2016-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.

  7. Long term effects of Escherichia coli mastitis.

    PubMed

    Blum, Shlomo E; Heller, Elimelech D; Leitner, Gabriel

    2014-07-01

    Escherichia coli is one of the most frequently diagnosed causes of bovine mastitis, and is typically associated with acute, clinical mastitis. The objective of the present study was to evaluate the long term effects of intramammary infections by E. coli on milk yield and quality, especially milk coagulation. Twenty-four Israeli Holstein cows diagnosed with clinical mastitis due to intramammary infection by E. coli were used in this study. Mean lactation number, days in milk (DIM) and daily milk yield (DMY) at the time of infection was 3.3 ± 1.3, 131.7 days ± 78.6 and 45.7 L ± 8.4, respectively. DMY, milk constituents, somatic cells count (SCC), differential leukocytes count and coagulation parameters were subsequently assessed. Two patterns of inflammation were identified: 'short inflammation', characterized by <15% decrease in DMY and <30 days until return to normal (n = 5), and 'long inflammation', characterized by >15% decrease in DMY and >30 days to reach a new maximum DMY (n = 19). The estimated mean loss of marketable milk during the study was 200 L/cow for 'short inflammation' cases, and 1,500 L/cow for 'long inflammation' ones. Significant differences between 'short' and 'long inflammation' effects were found in almost all parameters studied. Long-term detrimental effects on milk quality were found regardless of clinical or bacteriological cure of affected glands.

  8. Creeping eruption

    MedlinePlus

    ... JavaScript. Creeping eruption is a human infection with dog or cat hookworm larvae (immature worms). Causes Hookworm eggs are found in the stool of infected dogs and cats. When the eggs hatch, the larvae ...

  9. Can self-esteem, mastery and perceived stigma predict long-term adjustment in women carrying a BRCA1/2-mutation? Evidence from a multi-center study.

    PubMed

    Vodermaier, Andrea; Esplen, Mary Jane; Maheu, Christine

    2010-09-01

    Little is known about protective and vulnerability factors of long-term adjustment with BRCA1/2 carrier status. Specifically, the role of personal resources and perceptions of stigmatization have not been studied in the context of adjustment with hereditary breast cancer. The present study, therefore, explored associations of personal resources and stigma with cancer-specific anxiety in female BRCA1/2-carriers within a cross-sectional multi-center study. Participants (n = 237) had received carrier notification between 4 months and 8 years before data collection and experienced a low level of cancer-related anxiety on average. Younger age was associated with both higher perceptions of stigma (P = .002) and cancer-specific anxiety (P = .034). Time since receiving test results, affected status, having undergone prophylactic mastectomy or prophylactic oophorectomy was not associated with demographic or psychological variables. Global self-esteem (P = .002) and mastery (P < .001) were associated with fewer intrusive and avoidant thoughts, whereas stigma was associated with more (P < .001). Time since test result receipt did not moderate relations of self-esteem, mastery or stigma and cancer-specific anxiety. Cancer-specific anxiety did not vary as a function of time since carrier notification. Hence cancer-specific distress may be explained by past and ongoing experiences of cancer in the family rather than by the time point of carrier notification. Psychological interventions may benefit from specifically addressing feelings of stigmatization, and promoting self-worth and personal control in order to affect cancer-specific anxiety.

  10. Technology for long-term care.

    PubMed

    Tak, Sunghee H; Benefield, Lazelle E; Mahoney, Diane Feeney

    2010-01-01

    Severe staff shortages in long-term care (LTC) make it difficult to meet the demands of the growing aging population. Further, technology-savvy Baby Boomers are expected to reshape the current institutional environments toward gaining more freedom and control in their care and lives. Voices from business, academia, research, advocacy organizations, and government bodies suggest that innovative technological approaches are the linchpin that may prepare society to cope with these projected demands. In this article, we review the current state of aging-related technology, identify potential areas for efficacy testing on improving the quality of life of LTC residents in future research, and discuss barriers to implementation of LTC technology. Finally, we present a vision of future technology use that could transform current care practices.

  11. Long term performance of radon mitigation systems

    SciTech Connect

    Prill, R.; Fisk, W.J.

    2002-03-01

    Researchers installed radon mitigation systems in 12 houses in Spokane, Washington and Coeur d'Alene, Idaho during the heating season 1985--1986 and continued to monitor indoor radon quarterly and annually for ten years. The mitigation systems included active sub-slab ventilation, basement over-pressurization, and crawlspace isolation and ventilation. The occupants reported various operational problems with these early mitigation systems. The long-term radon measurements were essential to track the effectiveness of the mitigation systems over time. All 12 homes were visited during the second year of the study, while a second set 5 homes was visited during the fifth year to determine the cause(s) of increased radon in the homes. During these visits, the mitigation systems were inspected and measurements of system performance were made. Maintenance and modifications were performed to improve system performance in these homes.

  12. Long-term U. S. energy outlook

    SciTech Connect

    Friesen, G.

    1984-01-01

    Each year Chase Econometrics offers its clients a brief summary of the assumptions underlying the long-term energy forecast for the U.S. To illustrate the uncertainty involved in forecasting for the period to the year 2000, they choose to compare forecasts with some recent projections prepared by the Department of Energy's Office of Policy, Planning and Analysis for the annual National Energy Policy Plan supplement. Particular emphasis is placed on Scenario B, which is the mid-range reference case. As the introduction to the supplement emphasizes, the NEPP projections should not be considered a statement of the policy goals of the Reagan Administration. They represent an analysis of the possible evolution of U.S. energy markets, given current information and existing policies. The purpose of providing Scenario B as a reference case as well as Scenarios A and C as alternate cases is to show the sensitivity of oil price projections to small swings in energy demand.

  13. Withdrawal from long-term benzodiazepine treatment.

    PubMed Central

    Petursson, H; Lader, M H

    1981-01-01

    Long-term, normal-dose benzodiazepine treatment was discontinued in 16 patients who were suspected of being dependent on their medication. The withdrawal was gradual, placebo-controlled, and double-blind. All the patients experienced some form of withdrawal reaction, which ranged from anxiety and dysphoria to moderate affective and perceptual changes. Symptom ratings rose as the drugs were discontinued, but usually subsided to prewithdrawal levels over the nex