WorldWideScience

Sample records for backcalculation

  1. Will Nonlinear Backcalculation Help?

    DEFF Research Database (Denmark)

    Ullidtz, Per

    2000-01-01

    demonstrates, that treating the subgrade as a nonlinear elastic material, can result in more realistic moduli and a much better agreement between measured and calculated stresses and strains.The response of nonlinear elastic materials can be calculated using the Finite Element Method (FEM). A much simpler...... approach is to use the Method of Equivalent Thicknesses (MET), modified for a nonlinear subgrade. The paper includes an example where moduli backcalculated using FEM, linear elastic theory and MET are compared. Stresses and strains predicted by the three methods are also compared to measured values...

  2. System Identification Method for Evaluating the Effect of Thickness Error on Backcalculated Pavement Layer Moduli

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yan-hui; WANG Fu-ming; ZHANG Bei; CAI Ying-chun

    2004-01-01

    Based on system identification theory and FWD testing data, the effect of thickness error on backcalculating pavement layer moduli is studied and the method of singular value decomposition (SVD) is presented to solve the morbidity problem of sensitivity matrix in this paper.The results show that the thickness error has great effects on the backcalculated pavement layer moduli. The error of backcalculated moduli can be controlled within the range of ±15% by limiting the thickness error within the range of ±5%.

  3. Can backcalculation models unravel complex larval growth histories in a tropical freshwater fish?

    Science.gov (United States)

    Starrs, D; Ebner, B C; Fulton, C J

    2013-07-01

    This experimental study compared the precision and accuracy of the biological intercept (BI), modified fry (MF) and time-varying growth (TVG) backcalculation models in estimating the early growth of the tropical freshwater purple-spotted gudgeon Mogurnda adspersa. Larvae were reared up to 41 days post hatching under two temperatures and four different feeding regimes. Food and temperature treatments induced complex growth profiles among fish, and although total length (LT ) and otolith radius were related under all conditions, some uncoupling was evident in the otolith-somatic-growth (OSG) relationship of fish subjected to periods of changing food availability. Furthermore, otolith growth was found to be significantly influenced by temperature, but not by food availability. Analysis of backcalculation residuals by linear mixed effects modelling revealed that BI and TVG were equally precise in predicting somatic growth, with the highest accuracy provided by TVG. The performance of all the three models declined as the OSG relationship weakened under low-food conditions, with maximum errors estimated to be 39, 60 and 36% of observed LT for the BI, MF and TVG models, respectively. The need for careful validation of backcalculation models is emphasized when examining fishes subjected to variable environmental conditions, and when exploring the differential influence of temperature and food on fish LT and otolith growth.

  4. When did HIV incidence peak in Harare, Zimbabwe? Back-calculation from mortality statistics.

    Directory of Open Access Journals (Sweden)

    Ben Lopman

    Full Text Available HIV prevalence has recently begun to decline in Zimbabwe, a result of both high levels of AIDS mortality and a reduction in incident infections. An important component in understanding the dynamics in HIV prevalence is knowledge of past trends in incidence, such as when incidence peaked and at what level. However, empirical measurements of incidence over an extended time period are not available from Zimbabwe or elsewhere in sub-Saharan Africa. Using mortality data, we use a back-calculation technique to reconstruct historic trends in incidence. From AIDS mortality data, extracted from death registration in Harare, together with an estimate of survival post-infection, HIV incidence trends were reconstructed that would give rise to the observed patterns of AIDS mortality. Models were fitted assuming three parametric forms of the incidence curve and under nine different assumptions regarding combinations of trends in non-AIDS mortality and patterns of survival post-infection with HIV. HIV prevalence was forward-projected from the fitted incidence and mortality curves. Models that constrained the incidence pattern to a cubic spline function were flexible and produced well-fitting, realistic patterns of incidence. In models assuming constant levels of non-AIDS mortality, annual incidence peaked between 4 and 5% between 1988 and 1990. Under other assumptions the peak level ranged from 3 to 8% per annum. However, scenarios assuming increasing levels of non-AIDS mortality resulted in implausibly low estimates of peak prevalence (11%, whereas models with decreasing underlying crude mortality could be consistent with the prevalence and mortality data. HIV incidence is most likely to have peaked in Harare between 1988 and 1990, which may have preceded the peak elsewhere in Zimbabwe. This finding, considered alongside the timing and location of HIV prevention activities, will give insight into the decline of HIV prevalence in Zimbabwe.

  5. A novel length back-calculation approach accounting for ontogenetic changes in the fish length - otolith size relationship during the early life of sprat (Sprattus sprattus)

    DEFF Research Database (Denmark)

    Guenther, Claudia C.; Temming, Axel; Baumann, Hannes;

    2012-01-01

    An individual-based length back-calculation method was developed for juvenile Baltic sprat (Sprattus sprattus), accounting for ontogenetic changes in the relationship between fish length and otolith length. In sprat, metamorphosis from larvae to juveniles is characterized by the coincidence of low...

  6. Backcalculation of Resilient Modulus of Subgrade Based Two Point Surface Deflections%基于两点路表弯沉反算土基回弹模量的研究

    Institute of Scientific and Technical Information of China (English)

    杨国良; 吴旷怀

    2008-01-01

    基于层状弹性理论,利用远离承载板中心的两点路表变形响应反算土基回弹模量.根据半刚性基层沥青路面常用路面结构组合形式,构建土基回弹模量与两点路表弯沉值之间一一对应的数据库,建立回归模型.由理论弯沉盆和实测弯沉盆的预测结果表明,建立的土基回弹模量回归预测模型具有良好的精度和可靠性,为进一步快速、有效地评定土基的承载能力提供了依据.%Based on the layered elastic theory, the resilient modulus of subgrade was backcalculated using two point surface deflection responses of pavement structure where were further away from the center of bearing plate. According to the combinations of asphalt pavement on semi-rigid road for high-class highways in common use, the database of structural parameters and corresponding two point surface deflections was established and the regressive models were developed to backcalculate the resilient modulus of subgrade. The predictive results of theoretical and measured deflection basins showed that the regressive model of resilient modulus of subgrade was of good accuracy and reliability. It provids evidences to rapidly and effectively evaluate the bearing capacity of subgrade.

  7. Back-calculation of source strength and position by a hybrid genetic-Nelder Mead simplex algorithm%基于混合遗传-Nelder Mead单纯形算法的源强及位置反算

    Institute of Scientific and Technical Information of China (English)

    张建文; 王煜薇; 郑小平; 王正

    2011-01-01

    Determination of the locations and strength of the source in a chemical leakage is crucial to crowd evacuation and emergency decision. This paper compares concentrations computed by dispersion model with the measured by receptors and then hybrid genetic-Nelder Mead simplex algorithm model is established. The locations and strength of leakage source are characterized. The feasibility of the algorithm is verified by simulation data. It is indicated that the hybrid genetic-Nelder Mead simplex algorithm is seldom affected by initial values and can get good results even if the initial values are far away from the expected values. This method back-calculates the optimal solution in a smaller errors and a faster pace and is more suitable for the search procedure in multi-dimensional space. Thence, hybrid genetic-Nelder Mead simplex algorithm is able to back-calculate the locations and strength of leakage source quickly and accurately, which will meet the needs of emergency rescue.%确定泄漏源的位置和强度,是进行群体疏散和应急决策的基础.将扩散模型得到的浓度值与传感器观测的浓度值进行比较并建立混合遗传-Nelder Mead单纯形算法模型,反算得到泄露源的位置和强度,进而利用浓度的模拟数据验证该算法的可行性.研究结果表明:混合遗传-Nelder Mead单纯形算法不受初值选取的影响,即使初值远离期望值,也能得到很好的结果,而且能以较小的误差和较快的速度反算出结果,更适合于多维变量的搜索.因此混合遗传-Nelder Mead单纯形算法能够快速准确地反算得到泄漏源的位置和强度,满足应急决策的需要.

  8. Research on elastic modulus backcalculation of asphalt course using BP artificial neural network based on surface deflection basin of pavement%基于路表弯沉盆的BP人工神经网络反演沥青面层弹性模量研究

    Institute of Scientific and Technical Information of China (English)

    杨国良; 钟雯; 黄晓韵; 梁思敏; 何慧慧; 陈家驹

    2015-01-01

    Based on layered elastic theory,the elastic modulus of asphalt course in asphalt pavement was predicted using BP artificial neural network.According to the types of pavement structure in common use,the database of surface deflections with their corresponding structural parameters of asphalt course based on layered elastic theory was established.The elastic modulus backcalculation model of asphalt course in asphalt pavement was developed using BP artificial neural network to predict.The predictive results of asphalt course elastic modulus backcalculation using theoretical deflection basin and measured deflection basin indicate that the elastic modulus backcalculation model of asphalt course in asphalt pavement is of good predictive accuracy and reliability.It would provide the references with the elastic modulus backcalculation model of asphalt course to accurately and quickly estimate the conditions of asphalt course in asphalt pavement.%基于层状弹性体系理论,建立BP人工神经网络反演沥青路面沥青面层弹性模量预测模型,利用BP人工神经网络预测沥青路面沥青面层弹性模量.理论弯沉盆和实测弯沉盆反演沥青面层弹性模量的结果表明,建立的BP人工神经网络反演沥青路面沥青面层弹性模量模型具有良好的预测精度和可靠性,为评价沥青路面的沥青面层性能状况提供了参考.

  9. Reflective Cracking Study: Backcalculation of HVS Test Section Deflection Measurements

    OpenAIRE

    Lu, Qing; Jones, David; Harvey, John T

    2008-01-01

    This report is one in a series that describe the results of HVS testing and associated analyses on a full-scale experiment being performed at the Richmond Field Station (RFS) to validate Caltrans overlay strategies for the rehabilitation of cracked asphalt concrete. It describes the analysis of deflection data measured with a Falling Weight Deflectometer (FWD) throughout the study. The test forms part of Partnered Pavement Research Center Strategic Plan Element 4.10: “Development of Improved ...

  10. 应用弯沉盆反算土基回弹模量%Backcalculation of subgrade resilient modulus using deflection basin

    Institute of Scientific and Technical Information of China (English)

    杨国良; 王端宜; 张肖宁

    2009-01-01

    为准确反算土基回弹模量,利用层状弹性体系理论和冲击荷载沿路面结构下传扩散的特点,建立了路表变形响应与模量反算模型.通过层状弹性体系计算程序计算路表弯沉值,构建结构层参数与路表弯沉值之间一一对应的数据库,并基于此数据库建立了由路表弯沉盆反算土基回弹模量的回归模型.理论弯沉盆和实测弯沉盆反算的算例分析表明:计算结果与国内外一些著名的反算程序差异不大.距离荷载中心较远位置处的路表变形响应只受到土基的影响.

  11. 基于FWD弯沉数据的模量反算方法及影响因素%Modulus backcalculation method of deflection data based upon FWD and influencing factors

    Institute of Scientific and Technical Information of China (English)

    曹永; 朱朝辉

    2007-01-01

    从模量反算问题的提出入手,对模量反算的方法和模量反算的影响因素进行了探讨,通过一定的理论分析计算,进一步说明了基于FWD弯沉数据模量反算的科学性与可行性,可为后续研究提供理论基础.

  12. Back-calculation method shows that within-flock transmission of highly pathogenic avian influenza (H7N7) virus in the Netherlands is not influenced by housing risk factors

    NARCIS (Netherlands)

    Bos, M.E.H.; Nielen, M.; Koch, G.; Bouma, A.; Jong, de M.C.M.; Stegeman, J.A.

    2009-01-01

    To optimize control of an avian influenza outbreak knowledge of within-flock transmission is needed. This study used field data to estimate the transmission rate parameter (ß) and the influence of risk factors on within-flock transmission of highly pathogenic avian influenza (HPAI) H7N7 virus in the

  13. Estimating the day of highly pathogenic avian influenza (H7N7) virus introduction into a poultry flock based on mortality data

    OpenAIRE

    Bos, M.E.H.; Boven, van, M.; Nielen, M; Bouma, A.; Elbers, A.R.W.; Nodelijk, G.; Koch, G; Stegeman, A.; Jong, de, J.

    2007-01-01

    International audience Despite continuing research efforts, knowledge of the transmission of the highly pathogenic avian influenza (HPAI) virus still has considerable gaps, which complicates epidemic control. The goal of this research was to develop a model to back-calculate the day HPAI virus is introduced into a flock, based on within-flock mortality data. The back-calculation method was based on a stochastic SEIR (susceptible (S) - latently infected (E) - infectious (I) - removed (= dea...

  14. Estimating the day of highly pathogenic avian influenza (H7N7) virus introduction into a poultry flock based on mortality data

    NARCIS (Netherlands)

    Bos, M.E.H.; Boven, van R.M.; Nielen, M.; Bouma, A.; Elbers, A.R.W.; Nodelijk, G.; Koch, G.; Stegeman, A.; Jong, de M.C.M.

    2007-01-01

    Despite continuing research efforts, knowledge of the transmission of the highly pathogenic avian influenza (HPAI) virus still has considerable gaps, which complicates epidemic control. The goal of this research was to develop a model to back-calculate the day HPAI virus is introduced into a flock,

  15. Sea growth of anadromous brown trout (Salmo trutta)

    NARCIS (Netherlands)

    Leeuw, de J.J.; Hofstede, ter R.; Winter, H.V.

    2007-01-01

    Sea growth rates were studied in anadromous brown trout caught in Lake IJsselmeer, The Netherlands. Growth in the first year at sea was estimated at 26 cm from length-frequency distributions, and at 21 cm from back-calculated growth rates from scale readings. These estimates are considerably higher

  16. 75 FR 16037 - Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Proposed Exclusion

    Science.gov (United States)

    2010-03-31

    ... FR 27266 (May 16, 2001). III. EPA's Evaluation of the Waste Information and Data A. What Waste Did... copper and zinc to produce a brass coating. The facility generates F006 filter cake by the dewatering of... (carcinogenic risk of 10 -5 and non-cancer hazard index of 1.0). The DRAS program can back-calculate...

  17. Influence of Temperature on Mechanical Properties of Jute/Biopolymer Composites

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Laursen, Louise Løcke; Løgstrup Andersen, Tom;

    2013-01-01

    properties of two biomass-based polymers, polylactic acid (PLA) and cellulose acetate (CA), as a function of ambient temperature in the range from 5 to 80C. Tests were done for neat polymers and for jute fiber/biopolymer composites. Micromechanical models were applied to back-calculate the reinforcement....... For the jute fiber composites, both the elastic modulus and maximum stress are reduced when the temperature is increased. For the elastic modulus, this is shown to be due to a reduction in the reinforcement efficiency of the jute fibers; i.e., a reduction in the back-calculated effective elastic modulus......Biopolymers and natural fibers are receiving wide attention for the potential to have good performance composites with low environmental impact. A current limitation of most biopolymers is however their change in mechanical properties at elevated temperatures. This study investigates the mechanical...

  18. Solubility of clonazepam and diazepam in binary and ternary mixtures of polyethylene glycols 400 or 600, propylene glycol and water at 298.2K - experimental data and modeling

    Directory of Open Access Journals (Sweden)

    Bastami Zahra

    2014-01-01

    Full Text Available Experimental molar solubilities of clonazepam and diazepam in binary and ternary mixtures of polyethylene glycols (PEGs 400 or 600, propylene glycol (PG and water (138 data points along with the density of the saturated solutions at 298.2K were reported. The Jouyban-Acree model was used to fit to the measurements for providing a computational method. Employing the solubilities in the mono-solvents, the measured solubilities in mixed solvents were back-calculated and the overall mean percentage deviations (OMPDs of the model were 16.0 % and 19.2% for diazepam and clonazepam, respectively. Addition of the Hansen solubility parameters to the model helps us to train all the data sets (clonazepam and diazepam at once and the back-calculated OMPD for this analysis was 19.3%.

  19. Analysis of asphalt pavement structural response from an accelerated loading test

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study was to compare theoretical calculation and practical measurement structure response of asphalt pavement. Analysis of the pavement layer moduli was determined from a Back-calculation of Falling Weight Deflectometer (FWD) data and the measured stiffness moduli of asphalt layer cores. The pavement response was calculated using a theoretical model and the measured strain response at the bottom different layers.Layered elastic theory was used to back-calculate the layer moduli and three different theory models were used to forward calculate the strain and deflection. The models were: Layered Elastic Theory (LET), the Method of Equivalent Thicknesses (MET) with linear elastic and the Finite Element Method (FEM) where asphalt layer may be viscoelastic. The results showed that the calculation structure response from FEM was consistent with measured results.

  20. Growth and condition of bluegills in Wisconsin lakes: effects of population density and lake pH

    Science.gov (United States)

    Wiener, J.G.; Hanneman, W.R.

    1982-01-01

    Growth and condition of bluegills epomis macrochirusfrom five acidic lakes (pH 5.1-6.0) and six circumneutral lakes (pH 6.7-7.5) in northern Wisconsin were compared. Although mean condition factors and mean back-calculated total lengths at ages 1 to 4 varied significantly among lakes, the differences were not related to lake pH. Rather, the ranks of mean condition factors and back-calculated lengths at ages 2, 3, and 4 were negatively correlated with relative density of bluegills among the lakes. Because of the dominating effect of density, growth rates and condition factors are not useful as indicators of chronic, pH-related stress on bluegill populations.

  1. 地铁暗挖下穿既有建筑的参数反算与分析%Back-calculation and analysis of the existing structure under the subway beneath excavation

    Institute of Scientific and Technical Information of China (English)

    唐明明; 刘淼; 赵阳豪

    2015-01-01

    以长春地铁车站出入口通道暗挖穿越既有快速路为工程背景,研究了软弱粉质粘土层不均匀降水因素对既有结构的影响情况。采用粘聚力参数折减来近似拟合降水施工对暗挖所在地层的影响,根据实测沉降,建立了折减系数的反算格式。该方法简便易行,避开了现场孔隙压力测定,其沉降结果与实测结果一致,反算出的折减系数可用于同类工程中。根据反算结果,分析了暗挖施工对既有建筑物的安全性影响。%The influence of uneven dewatering in the weak silty clay stratum on the ex-isting structure is analyzed on the basis of the subway station project in Changchun,of which the entrance channel excavation is under the existing freeway.The effect of the existed pore pressure is summed up as the cohesion decreases with the reduction factor, and the back-calculation method is established according to the settlement of monitoring results.The back-calculation method is simple and convenient when the detailed pore pressure is hard to determine.The calculated settlement is consistent with the monito-ring data,so that the back-calculated reduction factor can be used in similar projects.Additionally,the safety of the existing structure under the beneath excavation of subway is analyzed according to the results of back-calculation.

  2. Age, growth, and mortality of the Mayan cichlid (Cichlasoma urophthalmus) from the southeastern Everglades

    OpenAIRE

    Faunce, Craig H.; Patterson, Heather M.; Lorenz, Jerome J.

    2002-01-01

    Mayan cichlids (Cichlasoma urophthalmus) were collected monthly from March 1996 to October 1997 with hook-and-line gear at Taylor River, Florida, an area within the Crocodile Sanctuary of Everglades National Park, where human activities such as fishing are prohibited. Fish were aged by examining thin-sectioned otoliths, and past size-at-age information was generated by using back-calculation techniques. Marginal increment analysis showed that opaque growth zones were annuli deposited between ...

  3. Noise-tolerant inverse analysis models for nondestructive evaluation of transportation infrastructure systems using neural networks

    Science.gov (United States)

    Ceylan, Halil; Gopalakrishnan, Kasthurirangan; Birkan Bayrak, Mustafa; Guclu, Alper

    2013-09-01

    The need to rapidly and cost-effectively evaluate the present condition of pavement infrastructure is a critical issue concerning the deterioration of ageing transportation infrastructure all around the world. Nondestructive testing (NDT) and evaluation methods are well-suited for characterising materials and determining structural integrity of pavement systems. The falling weight deflectometer (FWD) is a NDT equipment used to assess the structural condition of highway and airfield pavement systems and to determine the moduli of pavement layers. This involves static or dynamic inverse analysis (referred to as backcalculation) of FWD deflection profiles in the pavement surface under a simulated truck load. The main objective of this study was to employ biologically inspired computational systems to develop robust pavement layer moduli backcalculation algorithms that can tolerate noise or inaccuracies in the FWD deflection data collected in the field. Artificial neural systems, also known as artificial neural networks (ANNs), are valuable computational intelligence tools that are increasingly being used to solve resource-intensive complex engineering problems. Unlike the linear elastic layered theory commonly used in pavement layer backcalculation, non-linear unbound aggregate base and subgrade soil response models were used in an axisymmetric finite element structural analysis programme to generate synthetic database for training and testing the ANN models. In order to develop more robust networks that can tolerate the noisy or inaccurate pavement deflection patterns in the NDT data, several network architectures were trained with varying levels of noise in them. The trained ANN models were capable of rapidly predicting the pavement layer moduli and critical pavement responses (tensile strains at the bottom of the asphalt concrete layer, compressive strains on top of the subgrade layer and the deviator stresses on top of the subgrade layer), and also pavement

  4. Engineering geologic and geotechnical analysis of paleoseismic shaking using liquefaction effects: Field examples

    Science.gov (United States)

    Green, R.A.; Obermeier, S.F.; Olson, S.M.

    2005-01-01

    The greatest impediments to the widespread acceptance of back-calculated ground motion characteristics from paleoliquefaction studies typically stem from three uncertainties: (1) the significance of changes in the geotechnical properties of post-liquefied sediments (e.g., "aging" and density changes), (2) the selection of appropriate geotechnical soil indices from individual paleoliquefaction sites, and (3) the methodology for integration of back-calculated results of strength of shaking from individual paleoliquefaction sites into a regional assessment of paleoseismic strength of shaking. Presented herein are two case studies that illustrate the methods outlined by Olson et al. [Engineering Geology, this issue] for addressing these uncertainties. The first case study is for a site near Memphis, Tennessee, wherein cone penetration test data from side-by-side locations, one of liquefaction and the other of no liquefaction, are used to readily discern that the influence of post-liquefaction "aging" and density changes on the measured in situ soil indices is minimal. In the second case study, 12 sites that are at scattered locations in the Wabash Valley and that exhibit paleoliquefaction features are analyzed. The features are first provisionally attributed to the Vincennes Earthquake, which occurred around 6100 years BP, and are used to illustrate our proposed approach for selecting representative soil indices of the liquefied sediments. These indices are used in back-calculating the strength of shaking at the individual sites, the results from which are then incorporated into a regional assessment of the moment magnitude, M, of the Vincennes Earthquake. The regional assessment validated the provisional assumption that the paleoliquefaction features at the scattered sites were induced by the Vincennes Earthquake, in the main, which was determined to have M ??? 7.5. The uncertainties and assumptions used in the assessment are discussed in detail. ?? 2004 Elsevier B

  5. Nursery areas and recruitment variation of Northeast Atlantic mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis; Kristensen, Kasper; Van der Kooij, Jeroen;

    2015-01-01

    (LGC) process geostatistical model incorporating spatio-temporal correlations. A statistically significant correlation between the modelled catch rates in adjacent quarters 4 and 1 (Q4 and Q1) demonstrates that bottom-trawl surveys in winter are an appropriate platform for sampling juvenile mackerel...... the correlation between the derived annual recruitment index and recruitment estimated by backcalculation of adult mackerel data. Square root transformation led to the strongest correlation, so this is recommended for further analysis of mackerel abundance. Finally,we provide maps of spatial distributions...

  6. Sea growth of anadromous brown trout ( Salmo trutta)

    Science.gov (United States)

    de Leeuw, J. J.; ter Hofstede, R.; Winter, H. V.

    2007-08-01

    Sea growth rates were studied in anadromous brown trout caught in Lake IJsselmeer, The Netherlands. Growth in the first year at sea was estimated at 26 cm from length-frequency distributions, and at 21 cm from back-calculated growth rates from scale readings. These estimates are considerably higher than sea growth rates observed in populations at higher latitudes (Norway, Sweden), but compare well with the limited information on sea growth rates estimated for anadromous trout in the River Rhine and rivers in Normandy (France).

  7. Transmission of highly pathogenic avian influenza H7 virus

    OpenAIRE

    Bos, M.E.H.

    2009-01-01

    Knowledge of the transmission of highly pathogenic avian influenza (HPAI) virus still has gaps, complicating epidemic control. A model was developed to back-calculate the day HPAI virus was introduced into a flock, based on within-flock mortality data of the Dutch HPAI H7N7 epidemic (2003). The method was based on a stochastic epidemic model in which birds move from being susceptible, latently infected and infectious, to death. Our results indicated that two weeks can elapse before a noticeab...

  8. Toric intraocular lens orientation and residual refractive astigmatism: an analysis

    Directory of Open Access Journals (Sweden)

    Potvin R

    2016-09-01

    Full Text Available Rick Potvin,1 Brent A Kramer,2 David R Hardten,3 John P Berdahl4 1Science in Vision, Akron, NY, 2University of Iowa Carver College of Medicine, Iowa City, IA, 3Minnesota Eye Consultants, Minnetonka, MN, 4Vance Thompson Vision, Sioux Falls, SD, USA Purpose: To analyze intraocular lens (IOL orientation data from an online toric back-calculator (astigmatismfix.com for determining if differences were apparent by lens type.Methods: A retrospective review of astigmatismfix.com toric back-calculations that included IOL identification and intended orientation axis.Results: Of 12,812 total validated calculation records, 8,229 included intended orientation and lens identification data. Of the latter, 5,674 calculations (69% involved lenses oriented 5° or more from their intended position. Using estimated toric lens usage data, the percentage of lenses with orientation ≥5° from intended was 0.89% overall, but the percentage varied significantly between specific toric lens brands (P<0.05. The percentage of back-calculations related to lenses that were not oriented as intended was also statistically significantly different by lens brand (P<0.05. When IOLs were misoriented, they were significantly more likely to be misoriented in a counterclockwise direction (P<0.05. This was found to be due to a bias toward counterclockwise orientation observed with one specific brand, a bias that was not observed with the other three brands analyzed here.Conclusion: The percentage of eyes with lens orientation ≥5° from intended in the Toric Results Analyzer data set was <1% of toric IOLs in general, with the relative percentage of Tecnis® Toric IOLs significantly higher than AcrySof® Toric IOLs. Both of these had higher rates than the Staar® Toric and Trulign® Toric lenses, with the availability of higher Tecnis and AcrySof cylinder powers a likely contributing factor. The AcrySof Toric IOL appears to be less likely than the Tecnis Toric IOL to cause residual

  9. Age and growth in the indian major carp Labeo rohita (Cypriniformes: Cyprinidae) from tropical rivers of Ganga basin, India.

    Science.gov (United States)

    Mir, Javaid Iqbal; Sarkar, Uttam Kumar; Gusain, Om Prakash; Dwivedi, Arvind Kumar; Joukrushna, Jena

    2013-12-01

    Labeo rohita is a member of the Indian major carp species and originally an inhabitant of the Ganga river network in India. It is among the top ten aquaculture species of the world. Since there is a lack of information on the growth pattern of the wild populations of this species, this study aimed at evaluating the pattern of age and growth, to support the development of effective management plans. A total of 1082 samples of L. rohita were obtained from May 2009 to July 2012 in six drainages of the Ganga basin. Scales of the fish were used to determine the age and growth by analyzing the annual rings growth. Out of six populations, a maximum 8+ age classes were recorded from two rivers (Betwa and Sharda). The back-calculated lengths at 8+ age class ranged from 86.22 cm to 91.66 cm. However, for the rest of rivers up to 7+ age classes were recorded. Among growth parameters, specific rate of length increase (C(l)) and specific rate of weight increase (Cw) showed decreasing trend, and three distinct life stages of L. rohita were recorded based on growth constant data (C(lt)). Analysis of variance (ANOVA) of the back-calculated length data set of six populations indicated a significant difference (p Ganga basin.

  10. Microstructural Analysis and Rheological Modeling of Asphalt Mixtures Containing Recycled Asphalt Materials

    Directory of Open Access Journals (Sweden)

    Augusto Cannone Falchetto

    2014-09-01

    Full Text Available The use of recycled materials in pavement construction has seen, over the years, a significant increase closely associated with substantial economic and environmental benefits. During the past decades, many transportation agencies have evaluated the effect of adding Reclaimed Asphalt Pavement (RAP, and, more recently, Recycled Asphalt Shingles (RAS on the performance of asphalt pavement, while limits were proposed on the amount of recycled materials which can be used. In this paper, the effect of adding RAP and RAS on the microstructural and low temperature properties of asphalt mixtures is investigated using digital image processing (DIP and modeling of rheological data obtained with the Bending Beam Rheometer (BBR. Detailed information on the internal microstructure of asphalt mixtures is acquired based on digital images of small beam specimens and numerical estimations of spatial correlation functions. It is found that RAP increases the autocorrelation length (ACL of the spatial distribution of aggregates, asphalt mastic and air voids phases, while an opposite trend is observed when RAS is included. Analogical and semi empirical models are used to back-calculate binder creep stiffness from mixture experimental data. Differences between back-calculated results and experimental data suggest limited or partial blending between new and aged binder.

  11. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

    Science.gov (United States)

    Liu, Bilin; Chen, Xinjun; Chen, Yong; Tian, Siquan; Li, Jianhua; Fang, Zhou; Yang, Mingxia

    2013-01-01

    Age, maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008-2010. Estimated ages ranged from 144 to 633 days, confirming that the squid is a short-lived species with longevity no longer than 2 years. Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round. Back-calculated hatching dates for the samples were from January 22nd, 2008 to April 22nd, 2010 with a peak between January and March. Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates, respectively. Females matured at a larger size than males, and there was a significant difference in ML at maturity between the two hatching groups ( P <0.05). The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground. This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ, which should be considered in the assessment and management of this important resource.

  12. Evaluation of accelerated deterioration in NAPTF flexible test pavements

    Institute of Scientific and Technical Information of China (English)

    Kasthurirangan GOPALAKRISHNAN

    2008-01-01

    Previous research studies have successfully demonstrated the use of artificial neural network(ANN)models for predicting critical structural responses and layer moduli of highway flexible pavements.The primary objective of this study was to develop an ANN-based approach for backcalculation of pavement moduli based on heavy weight deflectometer(HWD)test data,especially in the analysis of airport flexible pavements subjected to new generation aircraft(NGA).Two medium-strength subgrade flexible test sections,at the National Airport Pavement Test Facility(NAPTF),were modeled using a finite element(FE) based pavement analysis program,which can consider the non-linear stress-dependent behavior of pavement geomaterials.A multi-layer,feed-forward network which uses an error-backpropagation algorithm was trained to approximate the HWD backcalculation function using the FE program generated synthetic database.At the NAPTF,test sections were subjected to Boeing 777 (B777)trafficking on one lane and Boeing 747(B747)trafficking on the other lane using a test machine.To monitor the effect of traffic and climatic variations on pavement structural responses.HWD tests were conducted on the traffieked lanes and on the untraffieked centerline of test sections as trafficking progressed.The trained ANN models were successfully applied on the actual HWD test data acquired at the NAPTF to predict the asphalt concrete moduli and non-1inear subgrade moduli of the medium-strength subgrade flexible test sections.

  13. Age and growth in the indian major carp Labeo rohita (Cypriniformes: Cyprinidae) from tropical rivers of Ganga basin, India.

    Science.gov (United States)

    Mir, Javaid Iqbal; Sarkar, Uttam Kumar; Gusain, Om Prakash; Dwivedi, Arvind Kumar; Joukrushna, Jena

    2013-12-01

    Labeo rohita is a member of the Indian major carp species and originally an inhabitant of the Ganga river network in India. It is among the top ten aquaculture species of the world. Since there is a lack of information on the growth pattern of the wild populations of this species, this study aimed at evaluating the pattern of age and growth, to support the development of effective management plans. A total of 1082 samples of L. rohita were obtained from May 2009 to July 2012 in six drainages of the Ganga basin. Scales of the fish were used to determine the age and growth by analyzing the annual rings growth. Out of six populations, a maximum 8+ age classes were recorded from two rivers (Betwa and Sharda). The back-calculated lengths at 8+ age class ranged from 86.22 cm to 91.66 cm. However, for the rest of rivers up to 7+ age classes were recorded. Among growth parameters, specific rate of length increase (C(l)) and specific rate of weight increase (Cw) showed decreasing trend, and three distinct life stages of L. rohita were recorded based on growth constant data (C(lt)). Analysis of variance (ANOVA) of the back-calculated length data set of six populations indicated a significant difference (p Ganga basin. PMID:24432546

  14. Ammonia emissions from an anaerobic digestion plant estimated using atmospheric measurements and dispersion modelling.

    Science.gov (United States)

    Bell, Michael W; Tang, Y Sim; Dragosits, Ulrike; Flechard, Chris R; Ward, Paul; Braban, Christine F

    2016-10-01

    Anaerobic digestion (AD) is becoming increasingly implemented within organic waste treatment operations. The storage and processing of large volumes of organic wastes through AD has been identified as a significant source of ammonia (NH3) emissions, however the totality of ammonia emissions from an AD plant have not been previously quantified. The emissions from an AD plant processing food waste were estimated through integrating ambient NH3 concentration measurements, atmospheric dispersion modelling, and comparison with published emission factors (EFs). Two dispersion models (ADMS and a backwards Lagrangian stochastic (bLS) model) were applied to calculate emission estimates. The bLS model (WindTrax) was used to back-calculate a total (top-down) emission rate for the AD plant from a point of continuous NH3 measurement downwind from the plant. The back-calculated emission rates were then input to the ADMS forward dispersion model to make predictions of air NH3 concentrations around the site, and evaluated against weekly passive sampler NH3 measurements. As an alternative approach emission rates from individual sources within the plant were initially estimated by applying literature EFs to the available site parameters concerning the chemical composition of waste materials, room air concentrations, ventilation rates, etc. The individual emission rates were input to ADMS and later tuned by fitting the simulated ambient concentrations to the observed (passive sampler) concentration field, which gave an excellent match to measurements after an iterative process. The total emission from the AD plant thus estimated by a bottom-up approach was 16.8±1.8mgs(-1), which was significantly higher than the back-calculated top-down estimate (7.4±0.78mgs(-1)). The bottom-up approach offered a more realistic treatment of the source distribution within the plant area, while the complexity of the site was not ideally suited to the bLS method, thus the bottom-up method is believed

  15. Phenomenon of transformed adiabatic shear band surrounded by deformed adiabatic shear band of ductile metal

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-bin

    2008-01-01

    The coexistent phenomenon of deformed and transformed adiabatic shear bands(ASBs) of ductile metal was analyzed using the JOHNSON-COOK model and gradient-dependent plasticity(GDP). The effects of melting point, density, heat capacity and work to heat conversion factor were investigated. Higher work to heat conversion factor, lower density, lower heat capacity and higher melting point lead to wider transformed ASB and higher local plastic shear deformation between deformed and transformed ASBs. Higher work to heat conversion factor, lower density, lower heat capacity and lower melting point cause higher local plastic shear deformation in the deformed ASB. Three reasons for the scatter in experimental data on the ASB width were pointed out and the advantages of the work were discussed. If the transformed ASB width is used to back-calculate the internal length parameter in the GDP, undoubtedly, the parameter will be extremely underestimated.

  16. Fisheries management of round sardinella Sardinella aurita along North Sinai coast

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mohamed Al-beak

    2016-01-01

    Objective:To estimate the biological and population parameters required for proposing a preparation to sustain and manage this valuable fish resource. Methods:Aging was done by scales reading, and growth was estimated by using the back-calculation method. The values of growth parameters L∞, k and to were calculated by von Bertalanffy model. Results: The results of growth parameters L∞, k and towere 28.36 cm, 0.184 per year and–0.843 7 per year, respectively. Mortality coefficient, survival and exploitation rates estimated to perceive yield per recruit and biomass per recruit. Conclusions: Biological reference points and virtual population analysis were prepared to plan appropriate managements forSardinella aurita fisheries.

  17. Seroincidence of non-typhoid Salmonella infections

    DEFF Research Database (Denmark)

    Emborg, H-D; Simonsen, J; Jørgensen, C S;

    2016-01-01

    The incidence of reported infections of non-typhoid Salmonella is affected by biases inherent to passive laboratory surveillance, whereas analysis of blood sera may provide a less biased alternative to estimate the force of Salmonella transmission in humans. We developed a mathematical model...... that enabled a back-calculation of the annual seroincidence of Salmonella based on measurements of specific antibodies. The aim of the present study was to determine the seroincidence in two convenience samples from 2012 (Danish blood donors, n = 500, and pregnant women, n = 637) and a community-based sample...... of healthy individuals from 2006 to 2007 (n = 1780). The lowest antibody levels were measured in the samples from the community cohort and the highest in pregnant women. The annual Salmonella seroincidences were 319 infections/1000 pregnant women [90% credibility interval (CrI) 210-441], 182/1000 in blood...

  18. Bayesian inference of protein structure from chemical shift data

    DEFF Research Database (Denmark)

    Bratholm, Lars Andersen; Christensen, Anders Steen; Hamelryck, Thomas Wim;

    2015-01-01

    Protein chemical shifts are routinely used to augment molecular mechanics force fields in protein structure simulations, with weights of the chemical shift restraints determined empirically. These weights, however, might not be an optimal descriptor of a given protein structure and predictive model......, and a bias is introduced which might result in incorrect structures. In the inferential structure determination framework, both the unknown structure and the disagreement between experimental and back-calculated data are formulated as a joint probability distribution, thus utilizing the full information...... content of the data. Here, we present the formulation of such a probability distribution where the error in chemical shift prediction is described by either a Gaussian or Cauchy distribution. The methodology is demonstrated and compared to a set of empirically weighted potentials through Markov chain...

  19. An approach to estimate the number of SARS cases imported by international air travel.

    Science.gov (United States)

    Goubar, A; Bitar, D; Cao, W C; Feng, D; Fang, L Q; Desenclos, J C

    2009-07-01

    The worldwide spread of severe acute respiratory syndrome (SARS) raised questions about the risk of importation of such infection, in particular by air travel. Entry screening was implemented in some countries although poor evidence on its effectiveness is reported. We developed a model to estimate the number of imported SARS cases between regions, using the 2003 SARS epidemic data to apply this model for two scenarios: from Beijing to Frankfurt and from Hong Kong to London. We back-calculated the data to estimate individuals' time of infection and built a model where every individual has a probability of being isolated, of traveling, and of being undetected at arrival. The findings, consistent with what was observed in 2003, suggest that entry screening does not affect the predicted number of imported cases. Inversely, importation depends on the transmission dynamic in the country of origin (including control measures in place) and on the intensity of air travel between regions. PMID:19079846

  20. Oxygen dynamics and transport in the Mediterranean sponge Aplysina aerophoba

    DEFF Research Database (Denmark)

    Hoffmann, F.; Røy, Hans; Bayer, K.;

    2008-01-01

    The Mediterranean sponge Aplysina aerophoba kept in aquaria or cultivation tanks can stop pumping for several hours or even days. To investigate changes in the chemical microenvironments, we measured oxygen profiles over the surface and into the tissue of pumping and non-pumping A. aerophoba...... specimens with Clark-type oxygen microelectrodes (tip diameters 18-30 μm). Total oxygen consumption rates of whole sponges were measured in closed chambers. These rates were used to back-calculate the oxygen distribution in a finite-element model. Combining direct measurements with calculations of diffusive...... flux and modeling revealed that the tissue of non-pumping sponges turns anoxic within 15 min, with the exception of a 1 mm surface layer where oxygen intrudes due to molecular diffusion over the sponge surface. Molecular diffusion is the only transport mechanism for oxygen into non-pumping sponges...

  1. Study on New Approaches for extended chemical management and REACH

    DEFF Research Database (Denmark)

    Lee, Jihyun

    2014-01-01

    exposure to phthalates (DEHP, DBP, and BBP) from the environment (indoor and outdoor environment) and food in Denmark and Korea were estimated. The daily childhood exposure levels of Korea are estimated higher than those of Denmark: 1.0-1.5 times in DEHP, 2.5-3.5 times in DBP, and 1.9-3.5 times in BBP......, a case study on the childhood phthalate exposures from food packaging made from recycled materials, and a simulation of the flows of phthalates in 2020 - under the assumption that the recycling rate of plastic and paper products will increase with the full implementation of EU waste legislations by 2020...... for median exposure levels. Then the result from exposure scenario approach (ESA) was compared with the result from back-calculation approach (BCA), using the concentrations of phthalate metabolites in children’s urine reflecting the actual exposure level of the target group. It was found that the exposure...

  2. Age-structured mark-recapture analysis: A virtual-population-analysis-based model for analyzing age-structured capture-recapture data

    Science.gov (United States)

    Coggins, L.G., Jr.; Pine, William E., III; Walters, C.J.; Martell, S.J.D.

    2006-01-01

    We present a new model to estimate capture probabilities, survival, abundance, and recruitment using traditional Jolly-Seber capture-recapture methods within a standard fisheries virtual population analysis framework. This approach compares the numbers of marked and unmarked fish at age captured in each year of sampling with predictions based on estimated vulnerabilities and abundance in a likelihood function. Recruitment to the earliest age at which fish can be tagged is estimated by using a virtual population analysis method to back-calculate the expected numbers of unmarked fish at risk of capture. By using information from both marked and unmarked animals in a standard fisheries age structure framework, this approach is well suited to the sparse data situations common in long-term capture-recapture programs with variable sampling effort. ?? Copyright by the American Fisheries Society 2006.

  3. Otolith microstructure analysis to resolve seasonal patterns of hatching and settlement in western Baltic cod

    DEFF Research Database (Denmark)

    Rehberg-Haas, Sabine; Hammer, Cornelius; Hillgruber, Nicola;

    2012-01-01

    differentiate between true annuli and secondary structures such as settlement checks. Otoliths were collected from fish off Fehmarn Island in 2008 and 2009, and were examined for macrostructural and microstructural patterns using light and scanning electron microscopy. All fish examined were age-0. Back......-calculation of hatch dates indicated hatching from April to June and from February to August in 2008 and 2009, respectively. Juveniles formed either one or two translucent rings. The first translucent ring started to form ∼3 months post-hatch and was interpreted as a settlement check, since it appeared to be a...... February and May, but were merged in those fish where settlement coincided with the seasonally formed second ring...

  4. Statistical estimations forPlasmodium vivaxmalaria in South Korea

    Institute of Scientific and Technical Information of China (English)

    Youngsaeng Lee; Hyeongap Jang; Jeong Ae Rhee; Jeong-Soo Park

    2015-01-01

    Objective:To calculate the numbers of weekly infections and prevalence of malaria, and to predict future trend of malaria incidences in South Korea.Methods:Weekly incidences of malaria for 13 years from the period 2001-2013 in South Korea were analyzed. The back-calculation equations were used with incubation period distributions. The maximum likelihood estimation for Poisson model was also used. The confidence intervals of the estimates were obtained by a bootstrap method. A regression model for time series of malaria incidences over 13 years was fitted by the non-linear least squares method, and used to predict futuretrend. Results:The estimated infection curve is narrower and more concentrated in the summer than in the incidence distribution. Infection started around the 19th week and was over around the 41st week. The maximum weekly infection 110 was obtained at the 29th week. The prevalence at the first week was around 496 persons, the minimum number was 366 at 22nd week, and the maximum prevalence was 648 at 34th week. Prevalence drops in late spring with people that falling ill and had had long incubation periods and rose in the summer with new infections. Our future forecast based on the regression model was that an increase at year 2014 compared to 2013 may reach a peak (at maximum about 70 weekly cases) at year 2015, with a decreasing trend after then.Conclusions:This work shows that back-calculation methods could work well in estimating the infection rates and the prevalence of malaria. The obtained results can be useful in establishing an efficient preventive program for malaria infection. The method presented here can be used in other countries where incidence data and incubation period are available.

  5. Structure refinement and membrane positioning of selectively labeled OmpX in phospholipid nanodiscs

    International Nuclear Information System (INIS)

    NMR structural studies on membrane proteins are often complicated by their large size, taking into account the contribution of the membrane mimetic. Therefore, classical resonance assignment approaches often fail. The large size of phospholipid nanodiscs, a detergent-free phospholipid bilayer mimetic, prevented their use in high-resolution solution-state NMR spectroscopy so far. We recently introduced smaller nanodiscs that are suitable for NMR structure determination. However, side-chain assignments of a membrane protein in nanodiscs still remain elusive. Here, we utilized a NOE-based approach to assign (stereo-) specifically labeled Ile, Leu, Val and Ala methyl labeled and uniformly 15N-Phe and 15N-Tyr labeled OmpX and calculated a refined high-resolution structure. In addition, we were able to obtain residual dipolar couplings (RDCs) of OmpX in nanodiscs using Pf1 phage medium for the induction of weak alignment. Back-calculated NOESY spectra of the obtained NMR structures were compared to experimental NOESYs in order to validate the quality of these structures. We further used NOE information between protonated lipid head groups and side-chain methyls to determine the position of OmpX in the phospholipid bilayer. These data were verified by paramagnetic relaxation enhancement (PRE) experiments obtained with Gd3+-modified lipids. Taken together, this study emphasizes the need for the (stereo-) specific labeling of membrane proteins in a highly deuterated background for high-resolution structure determination, particularly in large membrane mimicking systems like phospholipid nanodiscs. Structure validation by NOESY back-calculation will be helpful for the structure determination and validation of membrane proteins where NOE assignment is often difficult. The use of protein to lipid NOEs will be beneficial for the positioning of a membrane protein in the lipid bilayer without the need for preparing multiple protein samples

  6. Structure refinement and membrane positioning of selectively labeled OmpX in phospholipid nanodiscs

    Energy Technology Data Exchange (ETDEWEB)

    Hagn, Franz, E-mail: franz.hagn@tum.de; Wagner, Gerhard, E-mail: gerhard-wagner@hms.harvard.edu [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States)

    2015-04-15

    NMR structural studies on membrane proteins are often complicated by their large size, taking into account the contribution of the membrane mimetic. Therefore, classical resonance assignment approaches often fail. The large size of phospholipid nanodiscs, a detergent-free phospholipid bilayer mimetic, prevented their use in high-resolution solution-state NMR spectroscopy so far. We recently introduced smaller nanodiscs that are suitable for NMR structure determination. However, side-chain assignments of a membrane protein in nanodiscs still remain elusive. Here, we utilized a NOE-based approach to assign (stereo-) specifically labeled Ile, Leu, Val and Ala methyl labeled and uniformly {sup 15}N-Phe and {sup 15}N-Tyr labeled OmpX and calculated a refined high-resolution structure. In addition, we were able to obtain residual dipolar couplings (RDCs) of OmpX in nanodiscs using Pf1 phage medium for the induction of weak alignment. Back-calculated NOESY spectra of the obtained NMR structures were compared to experimental NOESYs in order to validate the quality of these structures. We further used NOE information between protonated lipid head groups and side-chain methyls to determine the position of OmpX in the phospholipid bilayer. These data were verified by paramagnetic relaxation enhancement (PRE) experiments obtained with Gd{sup 3+}-modified lipids. Taken together, this study emphasizes the need for the (stereo-) specific labeling of membrane proteins in a highly deuterated background for high-resolution structure determination, particularly in large membrane mimicking systems like phospholipid nanodiscs. Structure validation by NOESY back-calculation will be helpful for the structure determination and validation of membrane proteins where NOE assignment is often difficult. The use of protein to lipid NOEs will be beneficial for the positioning of a membrane protein in the lipid bilayer without the need for preparing multiple protein samples.

  7. Rock mass characterisation and stability analyses of excavated slopes

    Science.gov (United States)

    Zangerl, Christian; Lechner, Heidrun

    2016-04-01

    Excavated slopes in fractured rock masses are frequently designed for open pit mining, quarries, buildings, highways, railway lines, and canals. These slopes can reach heights of several hundreds of metres and in cases concerning open pit mines slopes larger than 1000 m are not uncommon. Given that deep-seated slope failures can cause large damage or even loss of life, the slope design needs to incorporate sufficient stability. Thus, slope design methods based on comprehensive approaches need to be applied. Excavation changes slope angle, groundwater flow, and blasting increases the degree of rock mass fracturing as well as rock mass disturbance. As such, excavation leads to considerable stress changes in the slopes. Generally, slope design rely on the concept of factor of safety (FOS), often a requirement by international or national standards. A limitation of the factor of safety is that time dependent failure processes, stress-strain relationships, and the impact of rock mass strain and displacement are not considered. Usually, there is a difficulty to estimate the strength of the rock mass, which in turn is controlled by an interaction of intact rock and discontinuity strength. In addition, knowledge about in-situ stresses for the failure criterion is essential. Thus, the estimation of the state of stress of the slope and the strength parameters of the rock mass is still challenging. Given that, large-scale in-situ testing is difficult and costly, back-calculations of case studies in similar rock types or rock mass classification systems are usually the methods of choice. Concerning back-calculations, often a detailed and standardised documentation is missing, and a direct applicability to new projects is not always given. Concerning rock mass classification systems, it is difficult to consider rock mass anisotropy and thus the empirical estimation of the strength properties possesses high uncertainty. In the framework of this study an approach based on

  8. Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes

    Science.gov (United States)

    Dale, Annabel; John, Cédric M.; Mozley, Peter S.; Smalley, P. C.; Muggeridge, Ann H.

    2014-05-01

    Septarian carbonate concretions contain carbonate precipitated during progressive growth of the concretion and subsequent fracture-filling. As such, they have been used to track variations in δ13C and δ18O of pore waters during diagenesis and to define diagenetic zones in clastic rocks. However, the δ18O value of the carbonate is dependent on precipitation temperature and the δ18O value of the pore fluid from which it precipitated. Interpretations must assume one of these parameters, both of which are highly variable through time in diagenetic settings. Carbonate clumped isotopes of the cement can provide independent estimates of temperature of precipitation, allowing the pore-water δ18O to be back-calculated. Here, we use this technique on carbonate concretions and fracture fills of the Upper Cretaceous Prairie Canyon Member, Mancos Shale, Colorado. We sampled concretions from two permeable horizons separated by a 5 m shale layer, with one permeable horizon containing concretions with septarian fractures. We show cores precipitated at cooler temperatures (31 °C, ˜660 m burial depth) than the rims (68 °C (˜1980 m burial depth) and relate that to the δ13Ccarbonate values to suggest the concretion core precipitated in the methanogenic zone, with increasing input from thermogenically produced CO2. The two concretion-bearing horizons have different back-calculated δ18Oporewater values (mean -2.65‰ and 1.13‰ VSMOW) for cements formed at the same temperature and similar δ13C values, suggesting the shale layer present between the two horizons acted as a barrier to fluid mixing. Additionally, the δ18Ocarbonate of the septarian fractures (-13.8‰ VPBD) are due to precipitation at high temperatures (102 to 115 °C) from a fluid with a mean δ18Oporewater of 0.32‰ (VSMOW). Therefore, we can tie in the cementation history of the formation to temporal and spatial variations in δ18Oporewater.

  9. Idades e crescimento da cioba, Ocyururs chrysurus, da Costa Central do Brasil Age and growth of yellowtail snapper, Ocyururs chrysurus, from Central Coast of Brazil

    Directory of Open Access Journals (Sweden)

    Júlio Neves de Araújo

    2002-01-01

    Full Text Available A idade e o crescimento da cioba da costa central do Brasil foram estudados a partir de leituras de otólitos obtidos em amostragens mensais de desembarques comerciais, realizados nas cidades de Vitória e Vila Velha, entre os anos de 1998 e 1999. Através da análise do incremento marginal, foi verificada a formação anual de uma zona translúcida a partir do final do outono e durante o inverno. Foram observadas ciobas de 2 a 19 anos. Os comprimentos furcais (CF médios retrocalculados variaram de 108 mm para idade 1 a 524 mm para idade 19. A equação de Von Bertalanffy ajustada aos CF médios retrocalculados foi CFt = 567,1 (1 - e -0.130 (t + 0.773. A relação comprimento peso foi P = 2,68x10-5CF2.914, onde P = peso total em gramas. O crescimento é lento, com os incrementos anuais em peso aumentando gradativamente até atingir o máximo de 164 g entre as idades 7 e 8 anos. Os resultados deste trabalho indicam que a cioba tem longa expectativa de vida e baixas taxas de crescimento somático, características das espécies mais sensíveis à exploração pesqueira.To age and study the growth of yellowtail snapper, we analyzed readings of otoliths obtained in monthly samplings from commercial landings in the cities of Vitória and Vila Velha, from 1998 to 1999. Marginal increment analysis showed that the formation of a translucent zone occurred in the early fall and during the winter. The observed ages range from 2 to 19 years. Mean back-calculated fork lengths (FL range from 108 mm for age 1 to 524 mm for age 19. The Von Bertalanffy growth equation fitted to the mean back-calculated FL was FLt = 567,1 (1 - e -0.130 (t + 0.773, The length-weight relationship was W= 2,68x10-5FL2.914, where W = whole weight in grams. Yellowtail snapper has a slow growth with annual growth increments in weight raising progressively to the maximum of 164 g between the 7 and 8 years. The yellowtail snapper has long lifespan and slow growth rates, features of

  10. Bond stress-slip mechanisms in high-performance fiber-reinforced cement composites

    Science.gov (United States)

    Guerrero Z., Aydee Patricia

    This research covers integrated experimental and analytical investigations of the mechanisms that influence the fiber pull-out versus slip response of typical fibers used in the production of fiber reinforced cementitious composites, in order to improve their mechanical performance. The fibers investigated include smooth steel fibers, hooked steel fibers, Torex twisted steel fibers and PVA (polyvinyl alcohol) fibers. Torex is a newly developed steel fiber, of general polygonal shape, that is twisted along its longitudinal axis to improve the mechanical component of bond. PVA fibers, currently used as replacement for asbestos fibers, have good mechanical properties and are believed to develop an adhesive or chemical bond component with cement matrices. Matrix parameters investigated comprised four different additives (fly ash, metakaolin, PVA polymer and latex) and the fineness of the sand. The experimental program included two types of tests, a single fiber pull-out test and a tensile test on notched prisms, considered an indirect test to measure bond. The first test was used when the fiber diameter exceeded 200 microns. The second test was primarily carried out for PVA fibers with a diameter in the range of 11 to 50 microns. Closed-loop control was used in the notched prism tests where the rate of crack opening at the notch controlled the machine displacement. Also in these tests, three different volume fractions of fibers were investigated for each parameter in order to back-calculate the bond strength. The analytical program includes three parts: (1) a study to model the contribution of the hook to the mechanical component of bond in hooked steel fibers, (2) a study to back-calculate adhesive-frictional bond of fine PVA fibers from the stress versus crack opening response of notched tensile prisms, and (3) a study to model the effect of twisting on the mechanical contribution of bond in Torex steel fibers. This last model utilizes a finite element code (based on

  11. Assessing artificial neural network performance in estimating the layer properties of pavements

    Directory of Open Access Journals (Sweden)

    Gloria Inés Beltran

    2014-07-01

    Full Text Available A major concern in assessing the structural condition of existing flexible pavements is the estimation of the mechanical properties of constituent layers, which is useful for the design and decision-making process in road management systems. This parameter identification problem is truly complex due to the large number of variables involved in pavement behavior. To this end, non-conventional adaptive or approximate solutions via Artificial Neural Networks – ANNs – are considered to properly map pavement response field measurements. Previous investigations have demonstrated the exceptional ability of ANNs in layer moduli estimation from non-destructive deflection tests, but most of the reported cases were developed using synthetic deflection data or hypothetical pavement systems. This paper presents further attempts to back-calculate layer moduli via ANN modeling, using a database gathered from field tests performed on three- and four-layer pavement systems. Traditional layer structuring and pavements with a stabilized subbase were considered. A three-stage methodology is developed in this study to design and validate an “optimum” ANN-based model, i.e., the best architecture possible along with adequate learning rules. An assessment of the resulting ANN model demonstrates its forecasting capabilities and efficiency in solving a complex parameter identification problem concerning pavements.

  12. Uncertainty of debris flow mobility relationships and its influence on the prediction of inundated areas

    Science.gov (United States)

    Simoni, Alessandro; Mammoliti, Maria; Berti, Matteo

    2011-09-01

    Empirical mobility relationships can be used for delineating debris flow inundated areas. A database of documented events in alpine mountain catchments of northeastern Italy is used to test the model DFlowz ( Berti and Simoni, 2007). We back-analyzed 25 DF events, ranging in volume from 3000 to 350,000 m 3, with the support of high resolution topographic information derived from LiDAR. The analysis makes use of an objective methodology for evaluating the accuracy of the predictions and involves the calibration of the model based on factors describing the uncertainty associated with the empirical relationships. Results indicate that the model is capable of reproducing the observed behavior with a maximum uncertainty of a factor of 3. The most relevant source of error lies in the estimation of the deposited volumes which affects the results of back-calculation and is mainly responsible also for the scatter associated with the empirical mobility relationships. On the contrary, the influence of different flow properties on the depositional process appears to play a minor role as the mutual relations between the three main scaling parameters (volume, inundated area, and cross-sectional area) are respected in the vast majority of cases and calibrated mobility coefficients show no significant relationship with the angle of reach of the deposit.

  13. Defining Product Intake Fraction to Quantify and Compare Exposure to Consumer Products.

    Science.gov (United States)

    Jolliet, Olivier; Ernstoff, Alexi S; Csiszar, Susan A; Fantke, Peter

    2015-08-01

    There is a growing consciousness that exposure studies need to better cover near-field exposure associated with products use. To consistently and quantitatively compare human exposure to chemicals in consumer products, we introduce the concept of product intake fraction, as the fraction of a chemical within a product that is eventually taken in by the human population. This metric enables consistent comparison of exposures during consumer product use for different product-chemical combinations, exposure duration, exposure routes and pathways and for other life cycle stages. We present example applications of the product intake fraction concept, for two chemicals in two personal care products and two chemicals encapsulated in two articles, showing how intakes of these chemicals can primarily occur during product use. We demonstrate the utility of the product intake fraction and its application modalities within life cycle assessment and risk assessment contexts. The product intake fraction helps to provide a clear interface between the life cycle inventory and impact assessment phases, to identify best suited sentinel products and to calculate overall exposure to chemicals in consumer products, or back-calculate maximum allowable concentrations of substances inside products.

  14. Refining the alkenone-pCO2 method: The role of algal growth conditions

    Science.gov (United States)

    Pearson, A.; Zhang, Y.; Huybers, P. J.; Pagani, M.

    2015-12-01

    The alkenone-pCO2 method based on carbon isotope fractionation during growth of haptophyte algae is one of the most widely used approaches to reconstruct atmospheric CO2 level in the Cenozoic. Based on the fractionation of stable carbon isotopes between dissolved CO2 and phytoplankton biomass, as represented by alkenone lipid biomarkers, this relationship (known as ɛp37:2) scales inversely with growth rate and cell volume to surface area ratio, and positively with CO2. Recently-published estimates for late Pleistocene CO2 levels, however, are poorly correlated with ice core CO2 records, suggesting that alkenone paleobarometry needs to be refined. Here we compiled published records over recent glacial-interglcial (G-IG) cycles and revised the relationship between algal growth rate, as expressed by the physiological parameter 'b', and dissolved phosphate concentration. We further show that the magnitude of change in ɛp37:2 over glacial-interglacial cycles at different sites is dependent on local nutrient conditions, highlighting the importance of constraining b for accurate CO2 estimates. The correlation between GDGT-2/3 ratio and back-calculated b at Ceara Rise (ODP Site 925) suggests that archaeal lipids could be used as proxies to calibrate b. Application of our variable-b method to reported data yields pCO2 estimates that are similar in both trends and magnitude to ice core-derived records.

  15. Characterization of transient groundwater flow through a high arch dam foundation during reservoir impounding

    Directory of Open Access Journals (Sweden)

    Yifeng Chen

    2016-08-01

    Full Text Available Even though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world's highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks, which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality (PVI method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results.

  16. The apparent elastic modulus of the juxtarticular subchondral bone of the femoral head.

    Science.gov (United States)

    Brown, T D; Vrahas, M S

    1984-01-01

    An experiment was undertaken to obtain approximate values for the intrinsic elastic modulus of subchondral bone. Shallow spherical caps, with uniform and incrementally controlled thickness, were machined from subchondral bone in the weight-bearing regions of 11 fresh-frozen normal femoral head autopsy specimens. Under application of polar point loads, the measured deflections were compared with a corresponding analytical shell solution, thus allowing back-calculation of the apparent modulus. Analogous tests were performed on similarly shaped specimens of stock Plexiglas of known modulus in order to estimate the precision of the testing method. The aggregate results for subchondral bone showed that its intrinsic stiffness correlated inversely with nominal shell thickness, but even the thinnest (1.0 mm thick) of these shells had an apparent modulus (mean = 1.372 GN/m2, SD = 414 MN/m2) well below that generally accepted for "pure" cortical bone (about 14 GN/m2). This stiffness deficit was very likely due to the presence of histologically evident marrow spaces. However, the low apparent modulus values measured in this study may not be fully representative of complex in vivo behavior, because in the testing of excised shells there is no radial compressive stress transfer to underlying cancellous bone.

  17. Identification of aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient vibration measurements

    DEFF Research Database (Denmark)

    Acampora, Antonio; Georgakis, Christos T.; Macdonald, J.H.G.;

    2014-01-01

    Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding and excit......Despite much research in recent years, large amplitude vibrations of inclined cables continue to be of concern for cable-stayed bridges. Various excitation mechanisms have been suggested, including rain-wind excitation, dry inclined cable galloping, high reduced velocity vortex shedding......-scale measurements are compared with the theoretical damping matrices based on the quasi-steady theory, using three different sets of wind tunnel measurements of static force coefficients on similar shaped twin or single cables, with good agreement. The damping terms are found to be dependent on Reynolds number...... in dry conditions.Finally, static drag coefficients are back-calculated from the full-scale vibration measurements, for first time, with reasonable agreement with direct wind tunnel measurements. The remaining discrepancies are believed to be due to the higher turbulence intensity on site than...

  18. A multi-state model to estimate incidence of heroin use

    Directory of Open Access Journals (Sweden)

    Sánchez-Niubò Albert

    2013-01-01

    Full Text Available Abstract Background Existing incidence estimates of heroin use are usually based on one information source. This study aims to incorporate more sources to estimate heroin use incidence trends in Spain between 1971 and 2005. Methods A multi-state model was constructed, whereby the initial state “heroin consumer” is followed by transition to either “admitted to first treatment” or to “left heroin use” (i.e. permanent cessation or death. Heroin use incidence and probabilities of entering first treatment ever were estimated following a back-calculation approach. Results The highest heroin use incidence rates in Spain, around 1.5 per 1,000 inhabitants aged 10–44, occurred between 1985 and 1990; subdividing by route of administration reveals higher incidences of injection between 1980 and 1985 (a mean of 0.62 per 1.000 and a peak for non-injectors in 1990 (0.867 per 1,000. Conclusions A simple conceptual model for heroin users’ trajectories related to treatment admission, provided a broader view of the historical trend of heroin use incidence in Spain.

  19. Evaluation of different smoking habits during music festivals through wastewater analysis.

    Science.gov (United States)

    Mackuľak, Tomáš; Grabic, Roman; Gál, Marián; Gál, Miroslav; Birošová, Lucia; Bodík, Igor

    2015-11-01

    Wastewater analysis is a powerful method that can provide useful information about the abuse of legal and illicit drugs. The aim of our study was to determine nicotine consumption during four different music festivals and to find a connection between smoking and preferences for specific music styles using wastewater analysis. The amount of the nicotine metabolite cotinine was monitored in wastewater at the influent of three waste water treatment plants WWTPs in the Czech Republic and Slovakia, where the festivals took place. Urinary bio-markers of nicotine utilization were analyzed by LC-HRMS. More than 80,000 festival participants were monitored during our study from June to September 2014. A significant increase of nicotine consumption was observed in wastewaters during music festivals. The nicotine ingestion level was back-calculated and expressed as mass of pure drug consumed per day and per 1000 inhabitants for selected cities of both countries. The highest differences between typical levels of cotinine in wastewaters and the levels during music festivals were detected in Piešťany: 4 g/L/1000 inhabitants during non-festival days compared to 8 g/L/1000 inhabitants during the Topfest pop-rock festival and 6g/L/1000 inhabitants during the Grape dance festival. No significant increase of the amounts of cotinine in wastewater was recorded for the Country and Folk festivals. PMID:26606646

  20. The cholesterol levels in median nerve and post-mortem interval evaluation.

    Science.gov (United States)

    Vacchiano, G; Maldonado, A Luna; Ros, M Matas; Di Lorenzo, P; Pieri, M

    2016-08-01

    Cholesterol levels in the median nerve were studied at various post-mortem intervals (PMIs). Single median nerve samples were collected from the wrists of 36 subjects during forensic autopsies of subjects with known circumstances and times of death. Although the absolute values varied, increments in cholesterol concentration were recorded. Subsequently, 16 subjects who did not suffer of any neurological and/or metabolic diseases with known times and circumstances of death were enrolled. For each enrolled subject, two samples were collected from the wrist at an interval of approximately two hours (t1 and t2). The obtained results revealed a gradual increase in cholesterol level with increasing time since death. The cholesterol concentration data obtained for each subject at t1 and t2 were correlated with the time since death, a linear interpolation was applied, and the PMI was back-calculated. Similar trends were obtained for the samples collected at similar PMIs; thus, three groups were considered: PMIPMIPMI>78h. Good correlation coefficients were obtained, especially for the first group (R(2)=0.9362) for which the PMI could be calculated with an error that ranged from -4 to 5.9h. Although it requires further confirmation via analyses of larger numbers of samples, the method proposed here can currently be applied to PMI determinations. PMID:26826850

  1. Seroincidence of non-typhoid Salmonella infections: convenience vs. random community-based sampling.

    Science.gov (United States)

    Emborg, H-D; Simonsen, J; Jørgensen, C S; Harritshøj, L H; Krogfelt, K A; Linneberg, A; Mølbak, K

    2016-01-01

    The incidence of reported infections of non-typhoid Salmonella is affected by biases inherent to passive laboratory surveillance, whereas analysis of blood sera may provide a less biased alternative to estimate the force of Salmonella transmission in humans. We developed a mathematical model that enabled a back-calculation of the annual seroincidence of Salmonella based on measurements of specific antibodies. The aim of the present study was to determine the seroincidence in two convenience samples from 2012 (Danish blood donors, n = 500, and pregnant women, n = 637) and a community-based sample of healthy individuals from 2006 to 2007 (n = 1780). The lowest antibody levels were measured in the samples from the community cohort and the highest in pregnant women. The annual Salmonella seroincidences were 319 infections/1000 pregnant women [90% credibility interval (CrI) 210-441], 182/1000 in blood donors (90% CrI 85-298) and 77/1000 in the community cohort (90% CrI 45-114). Although the differences between study populations decreased when accounting for different age distributions the estimates depend on the study population. It is important to be aware of this issue and define a certain population under surveillance in order to obtain consistent results in an application of serological measures for public health purposes.

  2. Thermal dimensioning of the deep repository. Influence of canister spacing, canister power, rock thermal properties and nearfield design on the maximum canister surface temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hoekmark, Harald; Faelth, Billy [Clay Technology AB, Lund (Sweden)

    2003-12-01

    The report addresses the problem of the minimum spacing required between neighbouring canisters in the deep repository. That spacing is calculated for a number of assumptions regarding the conditions that govern the temperature in the nearfield and at the surfaces of the canisters. The spacing criterion is that the temperature at the canister surfaces must not exceed 100 deg C .The results are given in the form of nomographic charts, such that it is in principle possible to determine the spacing as soon as site data, i.e. the initial undisturbed rock temperature and the host rock heat transport properties, are available. Results of canister spacing calculations are given for the KBS-3V concept as well as for the KBS-3H concept. A combination of numerical and analytical methods is used for the KBS-3H calculations, while the KBS-3V calculations are purely analytical. Both methods are described in detail. Open gaps are assigned equivalent heat conductivities, calculated such that the conduction across the gaps will include also the heat transferred by radiation. The equivalent heat conductivities are based on the emissivities of the different gap surfaces. For the canister copper surface, the emissivity is determined by back-calculation of temperatures measured in the Prototype experiment at Aespoe HRL. The size of the different gaps and the emissivity values are of great importance for the results and will be investigated further in the future.

  3. Larval distribution pattern of Muraenesox cinereus (Anguilliformes: Muraenesocidae) leptocephali in waters adjacent to Korea

    Science.gov (United States)

    Ji, Hwan-Sung; Kim, Jin-Koo; Oh, Taeg Yun; Choi, Kwang Ho; Choi, Jung Hwa; Seo, Young Il; Lee, Dong Woo

    2015-09-01

    To understand the transport and recruitment processes of the daggertooth pike conger, Muraenesox cinereus, in the marginal seas of East Asia, we investigated the distribution pattern, estimated spawning areas and periods, and recruitment mechanisms of M. cinereus, based on 51 individuals of leptocephali collected from Korean waters during 2010-2014. Back-calculated hatching dates, determined from the daily incremental growth rates of the otoliths, indicated that the spawning period for M. cinereus was during July-September. The size range of M. cinereus leptocephali collected offshore of Jeju Island and southeast of the Korea-Japan intermediate zone was 16.6-20.9 mm TL (age, 18-23 d). We hypothesize that one of the spawning grounds of M. cinereus is located offshore in the East China Sea. In Korean waters, the ages and body lengths of M. cinereus leptocephali increased northward from latitude 31°30'N to 34°40'N, with metamorphosis occurring at latitude 34°40'N. Therefore, we surmised that the hatched preleptocephali of M. cinereus were transported from offshore areas in the East China Sea to Jeju Island and the Korea Strait (KS) by the Kuroshio and Tsushima Warm Current.

  4. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    Science.gov (United States)

    Coroneos, Rula M.

    2012-01-01

    This report addresses the structural analysis and optimization of a composite fan blade sized for a large aircraft engine. An existing baseline solid metallic fan blade was used as a starting point to develop a hybrid honeycomb sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replacing the original baseline solid metallic fan model made of titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements, a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized whereas the overall blade thickness is held fixed so as to not alter the original airfoil geometry. Weight is taken as the objective function to be minimized by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  5. Modeling debris-flow runout patterns on two alpine fans with different dynamic simulation models

    Directory of Open Access Journals (Sweden)

    K. Schraml

    2015-02-01

    Full Text Available Predicting potential deposition areas of future debris-flow events is important for engineering hazard assessment in alpine regions. For this, numerical simulation models are commonly used tools. However, knowledge of appropriate model parameters is essential but often not available. In this study we use two numerical simulation models, RAMMS-DF (Rapid Mass Movement System – Debris Flow and DAN3D (Dynamic Analysis of Landslides in Three Dimensions, to back-calculate two well-documented debris-flow events in Austria and to compare the range and sensitivity of input parameters for the Voellmy flow model. All simulations are based on the same digital elevation model with a 1 m resolution and similar initial conditions. Our results show that both simulation tools are capable of matching observed deposition patterns. The best fit parameter set of μ [–] and ξ [m s−2] range between 0.07–0.11 and 200–300 m s−2, respectively, for RAMMS-DF, and 0.07–0.08 and 300–400 m s−2, respectively, for DAN3D. Sensitivity analyses show a higher sensitivity of model parameters for the DAN3D model than for the RAMMS-DF model. This study shall contribute to the evaluation of realistic model parameters for simulation of debris-flows in steep mountain catchments and highlights the sensitivity of the models.

  6. Quantitative Evaluation of Cross-Peak Volumes in Multidimensional Spectra by Nonlinear-Least-Squares Curve Fitting

    Science.gov (United States)

    Sze, K. H.; Barsukov, I. L.; Roberts, G. C. K.

    A procedure for quantitative evaluation of cross-peak volumes in spectra of any order of dimensions is described; this is based on a generalized algorithm for combining appropriate one-dimensional integrals obtained by nonlinear-least-squares curve-fitting techniques. This procedure is embodied in a program, NDVOL, which has three modes of operation: a fully automatic mode, a manual mode for interactive selection of fitting parameters, and a fast reintegration mode. The procedures used in the NDVOL program to obtain accurate volumes for overlapping cross peaks are illustrated using various simulated overlapping cross-peak patterns. The precision and accuracy of the estimates of cross-peak volumes obtained by application of the program to these simulated cross peaks and to a back-calculated 2D NOESY spectrum of dihydrofolate reductase are presented. Examples are shown of the use of the program with real 2D and 3D data. It is shown that the program is able to provide excellent estimates of volume even for seriously overlapping cross peaks with minimal intervention by the user.

  7. Determination of allowable subgrade frost heave with the pavement roughness index in numerical analysis

    Institute of Scientific and Technical Information of China (English)

    HongYan Ma; Feng Zhang; DeCheng Feng; Bo Lin

    2015-01-01

    Frost heave is an upward swelling of soil during cryogenic conditions in cold regions. It is caused by the accumulation of ice crystals in subgrade soil, which grow upwards when freezing temperatures penetrate into the subgrade. This study establishes the allowable soil subgrade frost heave based on the roughness standard of asphalt pavement in China, and aims to balance the pavement design and frost heave resistance of subgrades in cold regions. We formulated a mechanical model of pavement supported by the boundary conditions of differential frost heave, based on the elastic layered system theory. The differential soil subgrade frost heave was modeled as a sinusoidal function, and the allowable frost heave and the roughness index were modeled as the displacement boundaries for the top and bottom of the pavement structure. Then the allowable frost heave was back-calculated according to the roughness standard. Numerical results show that the allowable frost heave depends on the pavement structure, material properties, the highway grade, and other factors. In order to ensure that the actual soil subgrade frost heave is lower than the allowable frost heave, pavement structures and materials need to be selected and designed carefully. The numerical method proposed here can be applied to establish the frost heave re-sistance of subgrade when the pavement structure and materials are determined.

  8. Evaluation of different smoking habits during music festivals through wastewater analysis.

    Science.gov (United States)

    Mackuľak, Tomáš; Grabic, Roman; Gál, Marián; Gál, Miroslav; Birošová, Lucia; Bodík, Igor

    2015-11-01

    Wastewater analysis is a powerful method that can provide useful information about the abuse of legal and illicit drugs. The aim of our study was to determine nicotine consumption during four different music festivals and to find a connection between smoking and preferences for specific music styles using wastewater analysis. The amount of the nicotine metabolite cotinine was monitored in wastewater at the influent of three waste water treatment plants WWTPs in the Czech Republic and Slovakia, where the festivals took place. Urinary bio-markers of nicotine utilization were analyzed by LC-HRMS. More than 80,000 festival participants were monitored during our study from June to September 2014. A significant increase of nicotine consumption was observed in wastewaters during music festivals. The nicotine ingestion level was back-calculated and expressed as mass of pure drug consumed per day and per 1000 inhabitants for selected cities of both countries. The highest differences between typical levels of cotinine in wastewaters and the levels during music festivals were detected in Piešťany: 4 g/L/1000 inhabitants during non-festival days compared to 8 g/L/1000 inhabitants during the Topfest pop-rock festival and 6g/L/1000 inhabitants during the Grape dance festival. No significant increase of the amounts of cotinine in wastewater was recorded for the Country and Folk festivals.

  9. A meta-analysis of estimates of the AIDS incubation distribution.

    Science.gov (United States)

    Cooley, P C; Myers, L E; Hamill, D N

    1996-06-01

    Information from 12 studies is combined to estimate the AIDS incubation distribution with greater precision than is possible from a single study. The analysis uses a hierarchy of parametric models based on a four-parameter generalized F distribution. This general model contains four standard two-parameter distributions as special cases. The cases are the Weibull, gamma, log-logistic, lognormal distributions. These four special cases subsume three distinct asymptotic hazard behaviors. As time increases beyond the median of approximately 10 years, the hazard can increase to infinity (Weibull), can plateau at some constant level (gamma), or can decrease to zero (log-logistic and lognormal). The Weibull, gamma and 'log-logistic distributions' which represent the three distinct asymptotic hazard behaviors, all fit the data as well as the generalized F distribution at the 25 percent significance level. Hence, we conclude that incubation data is still too limited to ascertain the specific hazard assumption that should be utilized in studies of the AIDS epidemic. Accordingly, efforts to model the AIDS epidemic (e.g., back-calculation approaches) should allow the incubation distribution to take several forms to adequately represent HIV estimation uncertainty. It is recommended that, at a minimum, the specific Weibull, gamma and log-logistic distributions estimated in this meta-analysis should all be used in modeling the AIDS epidemic, to reflect this uncertainty.

  10. Ab initio diffuse-interface model for lithiated electrode interface evolution

    Science.gov (United States)

    Stournara, Maria E.; Kumar, Ravi; Qi, Yue; Sheldon, Brian W.

    2016-07-01

    The study of chemical segregation at interfaces, and in particular the ability to predict the thickness of segregated layers via analytical expressions or computational modeling, is a fundamentally challenging topic in the design of novel heterostructured materials. This issue is particularly relevant for the phase-field (PF) methodology, which has become a prominent tool for describing phase transitions. These models rely on phenomenological parameters that pertain to the interfacial energy and thickness, quantities that cannot be experimentally measured. Instead of back-calculating these parameters from experimental data, here we combine a set of analytical expressions based on the Cahn-Hilliard approach with ab initio calculations to compute the gradient energy parameter κ and the thickness λ of the segregated Li layer at the LixSi-Cu interface. With this bottom-up approach we calculate the thickness λ of the Li diffuse interface to be on the order of a few nm, in agreement with prior experimental secondary ion mass spectrometry observations. Our analysis indicates that Li segregation is primarily driven by solution thermodynamics, while the strain contribution in this system is relatively small. This combined scheme provides an essential first step in the systematic evaluation of the thermodynamic parameters of the PF methodology, and we believe that it can serve as a framework for the development of quantitative interface models in the field of Li-ion batteries.

  11. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture--Conceptual Framework.

    Science.gov (United States)

    Schowanek, D; Carr, R; David, H; Douben, P; Hall, J; Kirchmann, H; Patria, L; Sequi, P; Smith, S; Webb, S

    2004-12-01

    This paper describes a systematic methodology (Conceptual Framework) to derive quality standards for organic (anthropogenic) contaminants in sewage sludge added to agricultural land, in the context of revision of EU Sludge Directive 86/278/EEC and the broader Soil Thematic Strategy. The overall objective is to ensure, based on a risk assessment approach, a sustainable use of sludge over a long time horizon. ILSI-Europe's Conceptual Framework is in essence consistent with the EU Technical Guidance Document (TGD) for Environmental Risk Assessment of Chemicals in the soil compartment, or US-EPA's Sewage Sludge Use and Disposal Regulations, Part 503 Standards. A 'checklist' of different exposure pathways and transfer processes for organic contaminants needs to be considered, and the most sensitive relevant toxicological endpoint and its PNEC need to be identified. The additional complexity specific to deriving Sludge Quality Standards (SQS) is that the toxicity results may need-e.g., for (indirect) human toxicity-to be related back to maximum acceptable soil exposure levels (PEC(soil)). In turn, the latter need to be back-calculated to the maximum acceptable levels in sewage sludge (PEC(sludge)) at the time of application. Finally, for a sustainable sludge use, the exposure from repeated addition and potential chemical build-up over time (e.g., 100 years) needs to be assessed. The SQS may therefore vary with the (local) sludge application regime, and/or sludge pretreatment processes.

  12. A preliminary analysis of trace-elemental signatures in statoliths of different spawning cohorts for Dosidicus gigas off EEZ waters of Chile

    Science.gov (United States)

    Liu, Bilin; Chen, Xinjun; Fang, Zhou; Hu, Song; Song, Qian

    2015-12-01

    We applied solution-based ICP-MS method to quantify the trace-elemental signatures in statoliths of jumbo flying squid, Dosidius gigas, which were collected from the waters off northern and central Chile during the scientific surveys carried out by Chinese squid jigging vessels in 2007 and 2008. The age and spawning date of the squid were back-calculated based on daily increments in statoliths. Eight elemental ratios (Sr/Ca, Ba/Ca, Mg/Ca, Mn/Ca, Na/Ca, Fe/Ca, Cu/Ca and Zn/Ca) were analyzed. It was found that Sr is the second most abundant element next to Ca, followed by Na, Fe, Mg, Zn, Cu, Ba and Mn. There was no significant relationship between element/Ca and sea surface temperature (SST) and sea surface salinity (SSS), although weak negative or positive tendency was found. MANOVA analysis showed that multivariate elemental signatures did not differ among the cohorts spawned in spring, autumn and winter, and no significant difference was found between the northern and central sampling locations. Classification results showed that all individuals of each spawned cohorts were correctly classified. This study demonstrates that the elemental signatures in D. gigas statoliths are potentially a useful tool to improve our understanding of its population structure and habitat environment.

  13. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones

    Institute of Scientific and Technical Information of China (English)

    LIU Bilin; CHEN Xinjun; CHEN Yong; TIAN Siquan; LI Jianhua; FANG Zhou; YANG Mingxia

    2013-01-01

    Age,maturation and population structure of the Humboldt squid Dosidicus gigas were studied based on random sampling of the Chinese jigging fishery off the Peruvian Exclusive Economic Zones (EEZ) during 2008-2010.Estimated ages ranged from 144 to 633 days,confirming that the squid is a short-lived species with longevity no longer than 2 years.Occurrence of mature females and hatching in each month indicated that Humboldt squid spawned year-round.Back-calculated hatching dates for the samples were from January 22nd,2008 to April 22nd,2010 with a peak between January and March.Two size-based and two hatching date-based populations could be defined from mantle length (ML) at maturity and back-calculated hatching dates,respectively.Females matured at a larger size than males,and there was a significant difference in ML at maturity between the two hatching groups (P<0.05).The waters adjacent to 11°S off the Peruvian EEZ may be a potential spawning ground.This study shows the complexity of the population structure and large variability in key life history parameters in the Humboldt squid off the Peruvian EEZ,which should be considered in the assessment and management of this important resource.

  14. Effect of deep injection on field-scale emissions of 1,3-dichloropropene and chloropicrin from bare soil

    Science.gov (United States)

    Yates, S. R.; Ashworth, D. J.; Zheng, W.; Knuteson, J.; van Wesenbeeck, I. J.

    2016-07-01

    Fumigating soil is important for the production of many high-value vegetable, fruit, and tree crops, but fumigants are toxic pesticides with relatively high volatility, which can lead to significant atmospheric emissions. A field experiment was conducted to measure emissions and subsurface diffusion of a mixture of 1,3-dichloropropene (1,3-D) and chloropicrin after shank injection to bare soil at 61 cm depth (i.e., deep injection). Three on-field methods, the aerodynamic (ADM), integrated horizontal flux (IHF), and theoretical profile shape (TPS) methods, were used to obtain fumigant flux density and cumulative emission values. Two air dispersion models (CALPUFF and ISCST3) were also used to back-calculate the flux density using air concentration measurements surrounding the fumigated field. Emissions were continuously measured for 16 days and the daily peak emission rates for the five methods ranged from 13 to 33 μg m-2 s-1 for 1,3-D and 0.22-3.2 μg m-2 s-1 for chloropicrin. Total 1,3-D mass lost to the atmosphere was approximately 23-41 kg ha-1, or 15-27% of the applied active ingredient and total mass loss of chloropicrin was soil fumigants deeper in soil.

  15. Semi-physical Identification and State Estimation of Energy Intake for Interventions to Manage Gestational Weight Gain

    Science.gov (United States)

    Guo, Penghong; Rivera, Daniel E.; Downs, Danielle S.; Savage, Jennifer S.

    2016-01-01

    Excessive gestational weight gain (i.e., weight gain during pregnancy) is a significant public health concern, and has been the recent focus of novel, control systems-based interventions. This paper develops a control-oriented dynamical systems model based on a first-principles energy balance model from the literature, which is evaluated against participant data from a study targeted to obese and overweight pregnant women. The results indicate significant under-reporting of energy intake among the participant population. A series of approaches based on system identification and state estimation are developed in the paper to better understand and characterize the extent of under-reporting; these range from back-calculating energy intake from a closed-form of the energy balance model, to a constrained semi-physical identification approach that estimates the extent of systematic under-reporting in the presence of noise and possibly missing data. Additionally, we describe an adaptive algorithm based on Kalman filtering to estimate energy intake in real-time. The approaches are illustrated with data from both simulated and actual intervention participants. PMID:27570366

  16. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine

    Science.gov (United States)

    Coroneos, Rula M.; Gorla, Rama Subba Reddy

    2012-09-01

    This paper addresses the structural analysis and optimization of a composite sandwich ply lay-up of a NASA baseline solid metallic fan blade comparable to a future Boeing 737 MAX aircraft engine. Sandwich construction with a polymer matrix composite face sheet and honeycomb aluminum core replaces the original baseline solid metallic fan model made of Titanium. The focus of this work is to design the sandwich composite blade with the optimum number of plies for the face sheet that will withstand the combined pressure and centrifugal loads while the constraints are satisfied and the baseline aerodynamic and geometric parameters are maintained. To satisfy the requirements a sandwich construction for the blade is proposed with composite face sheets and a weak core made of honeycomb aluminum material. For aerodynamic considerations, the thickness of the core is optimized where as the overall blade thickness is held fixed in order not to alter the original airfoil geometry. Weight reduction is taken as the objective function by varying the core thickness of the blade within specified upper and lower bounds. Constraints are imposed on radial displacement limitations and ply failure strength. From the optimum design, the minimum number of plies, which will not fail, is back-calculated. The ply lay-up of the blade is adjusted from the calculated number of plies and final structural analysis is performed. Analyses were carried out by utilizing the OpenMDAO Framework, developed at NASA Glenn Research Center combining optimization with structural assessment.

  17. A framework for assessing risk reduction due to DNAPL mass removal from low permeability soils

    Energy Technology Data Exchange (ETDEWEB)

    Freeze, R.A. [R. Allan Freeze Engineering, Inc., White Rock, British Columbia (Canada); McWhorter, D.B. [Colorado State Univ., Fort Collins, CO (United States)

    1996-08-01

    Many emerging remediation technologies are designed to remove contaminant mass from source zones at DNAPL sites in response to regulatory requirements. There is often concern in the regulated community as to whether mass removal actually reduces risk, or whether the small risk reductions achieved warrant the large costs incurred. This paper sets out a framework for quantifying the degree to which risk is reduced as mass is removed from shallow, saturated, low-permeability, dual-porosity, DNAPL source zones. Risk is defined in terms of meeting an alternate concentration level (ACL) at a compliance well in an aquifer underlying the source zone. The ACL is back-calculated from a carcinogenic health-risk characterization at a downstream water-supply well. Source-zone mass-removal efficiencies are heavily dependent on the distribution of mass between media (fractures, matrix) and phases (dissolved, sorbed, free product). Due to the uncertainties in currently-available technology performance data, the scope of the paper is limited to developing a framework for generic technologies rather than making risk-reduction calculations for specific technologies. Despite the qualitative nature of the exercise, results imply that very high mass-removal efficiencies are required to achieve significant long-term risk reduction with technology, applications of finite duration. 17 refs., 7 figs., 6 tabs.

  18. Efficiency of paramagnetism-based constraints to determine the spatial arrangement of {alpha}-helical secondary structure elements

    Energy Technology Data Exchange (ETDEWEB)

    Bertini, Ivano [University of Florence, CERM and Department of Chemistry (Italy)], E-mail: bertini@cerm.unifi.it; Longinetti, Marco [Dipartimento di Ingegneria Agraria e Forestale (Italy); Luchinat, Claudio; Parigi, Giacomo [University of Florence, CERM and Department of Agricultural Biotechnology (Italy); Sgheri, Luca [Istituto di Analisi Globale ed Applicazioni (CNR) (Italy)

    2002-02-15

    A computational approach has been developed to assess the power of paramagnetism-based backbone constraints with respect to the determination of the tertiary structure, once the secondary structure elements are known. This is part of the general assessment of paramagnetism-based constraints which are known to be relevant when used in conjunction with all classical constraints. The paramagnetism-based constraints here investigated are the pseudocontact shifts, the residual dipolar couplings due to self-orientation of the metalloprotein in high magnetic fields, and the cross correlation between dipolar relaxation and Curie relaxation. The relative constraints are generated by back-calculation from a known structure. The elements of secondary structure are supposed to be obtained from chemical shift index. The problem of the reciprocal orientation of the helices is addressed. It is shown that the correct fold can be obtained depending on the length of the {alpha}-helical stretches with respect to the length of the non helical segments connecting the {alpha}-helices. For example, the correct fold is straightforwardly obtained for the four-helix bundle protein cytochrome b{sub 562}, while the double EF-hand motif of calbindin D{sub 9k} is hardly obtained without ambiguity. In cases like calbindin D{sub 9k}, the availability of datasets from different metal ions is helpful, whereas less important is the location of the metal ion with respect to the secondary structure elements.

  19. The ARTμS: a novel microfluidic CD4+ T-cell enumeration system for monitoring antiretroviral therapy in HIV patients.

    Science.gov (United States)

    Liu, Qian; Chernish, Alexis; DuVall, Jacquelyn A; Ouyang, Yiwen; Li, Jingyi; Qian, Qiang; Bazydlo, Lindsay A L; Haverstick, Doris M; Landers, James P

    2016-02-01

    We report on a novel and cost-effective microfluidic platform that integrates immunomagnetic separation and cell enumeration via DNA-induced bead aggregation. Using a two-stage immunocapture microdevice, 10 μL of whole blood was processed to isolate CD4+ T-cells. The first stage involved the immuno-subtraction of monocytes by anti-CD14 magnetic beads, followed by CD4+ T-cell capture with anti-CD4 magnetic beads. The super hydrophilic surface generated during polydimethylsiloxane (PDMS) plasma treatment allowed for accurate metering of the CD4+ T-cell lysate, which then interacted with silica-coated magnetic beads under chaotropic conditions to form aggregates. Images of the resulting aggregates were captured and processed to reveal the mass of DNA, which was used to back-calculate the CD4+ T-cell number. Studies with clinical samples revealed that the analysis of blood within 24 hours of phlebotomy yielded the best results. Under these conditions, an accurate cell count was achieved (R(2) = 0.98) when compared to cell enumeration via flow cytometry, and over a functional dynamic range from 106-2337 cells per μL. PMID:26687070

  20. The apparent elastic modulus of the juxtarticular subchondral bone of the femoral head.

    Science.gov (United States)

    Brown, T D; Vrahas, M S

    1984-01-01

    An experiment was undertaken to obtain approximate values for the intrinsic elastic modulus of subchondral bone. Shallow spherical caps, with uniform and incrementally controlled thickness, were machined from subchondral bone in the weight-bearing regions of 11 fresh-frozen normal femoral head autopsy specimens. Under application of polar point loads, the measured deflections were compared with a corresponding analytical shell solution, thus allowing back-calculation of the apparent modulus. Analogous tests were performed on similarly shaped specimens of stock Plexiglas of known modulus in order to estimate the precision of the testing method. The aggregate results for subchondral bone showed that its intrinsic stiffness correlated inversely with nominal shell thickness, but even the thinnest (1.0 mm thick) of these shells had an apparent modulus (mean = 1.372 GN/m2, SD = 414 MN/m2) well below that generally accepted for "pure" cortical bone (about 14 GN/m2). This stiffness deficit was very likely due to the presence of histologically evident marrow spaces. However, the low apparent modulus values measured in this study may not be fully representative of complex in vivo behavior, because in the testing of excised shells there is no radial compressive stress transfer to underlying cancellous bone. PMID:6491796

  1. Cross-validation of a mass spectrometric-based method for the therapeutic drug monitoring of irinotecan: implementation of matrix-assisted laser desorption/ionization mass spectrometry in pharmacokinetic measurements.

    Science.gov (United States)

    Calandra, Eleonora; Posocco, Bianca; Crotti, Sara; Marangon, Elena; Giodini, Luciana; Nitti, Donato; Toffoli, Giuseppe; Traldi, Pietro; Agostini, Marco

    2016-07-01

    Irinotecan is a widely used antineoplastic drug, mostly employed for the treatment of colorectal cancer. This drug is a feasible candidate for therapeutic drug monitoring due to the presence of a wide inter-individual variability in the pharmacokinetic and pharmacodynamic parameters. In order to determine the drug concentration during the administration protocol, we developed a quantitative MALDI-MS method using CHCA as MALDI matrix. Here, we demonstrate that MALDI-TOF can be applied in a routine setting for therapeutic drug monitoring in humans offering quick and accurate results. To reach this aim, we cross validated, according to FDA and EMA guidelines, the MALDI-TOF method in comparison with a standard LC-MS/MS method, applying it for the quantification of 108 patients' plasma samples from a clinical trial. Standard curves for irinotecan were linear (R (2) ≥ 0.9842) over the concentration ranges between 300 and 10,000 ng/mL and showed good back-calculated accuracy and precision. Intra- and inter-day precision and accuracy, determined on three quality control levels were always <12.8 % and between 90.1 and 106.9 %, respectively. The cross-validation procedure showed a good reproducibility between the two methods, the percentage differences within 20 % in more than 70 % of the total amount of clinical samples analysed. PMID:27235158

  2. A New Method for Estimating the Number of Undiagnosed HIV Infected Based on HIV Testing History, with an Application to Men Who Have Sex with Men in Seattle/King County, WA.

    Directory of Open Access Journals (Sweden)

    Ian E Fellows

    Full Text Available We develop a new approach for estimating the undiagnosed fraction of HIV cases, the first step in the HIV Care Cascade. The goal is to address a critical blindspot in HIV prevention and treatment planning, with an approach that simplifies data requirements and can be implemented with open-source software. The primary data required is HIV testing history information on newly diagnosed cases. Two methods are presented and compared. The first is a general methodology based on simplified back-calculation that can be used to assess changes in the undiagnosed fraction over time. The second makes an assumption of constant incidence, allowing the estimate to be expressed as a simple closed formula calculation. We demonstrate the methods with an application to HIV diagnoses among men who have sex with men (MSM from Seattle/King County. The estimates suggest that 6% of HIV-infected MSM in King County are undiagnosed, about one-third of the comparable national estimate. A sensitivity analysis on the key distributional assumption gives an upper bound of 11%. The undiagnosed fraction varies by race/ethnicity, with estimates of 4.9% among white, 8.6% of African American, and 9.3% of Hispanic HIV-infected MSM being undiagnosed.

  3. Pavement thickness and stabilised foundation layer assessment using ground-coupled GPR

    Science.gov (United States)

    Hu, Jinhui; Vennapusa, Pavana K. R.; White, David J.; Beresnev, Igor

    2016-07-01

    Experimental results from field and laboratory investigations using a ground-coupled ground penetrating radar (GPR), dielectric measurement, magnetic imaging tomography (MIT) and dynamic cone penetrometer (DCP) tests are presented. Dielectric properties of asphalt pavement and stabilised and unstabilised pavement foundation materials were evaluated in the laboratory in frozen and unfrozen conditions. Laboratory test results showed that dielectric properties of materials back-calculated from GPR in comparison to dielectric gauge measurements are strongly correlated and repeatable. For chemically stabilised materials, curing time affected the dielectric properties of the materials. Field tests were conducted on asphalt pavement test sections with different foundation materials (stabilised and unstabilised layers), drainage conditions and layer thicknesses. GPR and MIT results were used to determine asphalt layer thicknesses and were compared with measured core thicknesses, while GPR and DCP were used to assess foundation layer profiles. Asphalt thicknesses estimated from GPR showed an average error of about 11% using the dielectric gauge values as input. The average error reduced to about 4% when calibrated with cores thicknesses. MIT results showed thicknesses that are about 9% higher than estimated using GPR. Foundation layer thicknesses could not be measured using GPR due to variations in moisture conditions between the test sections, which is partly attributed to variations in gradation and drainage characteristics of the subbase layer.

  4. Trade-off between resource allocation and acquisition in anadromous adult male Atlantic salmon (Salmo salar L.

    Directory of Open Access Journals (Sweden)

    Tomislav Vladic

    2014-06-01

    Full Text Available Individual energetic limitations in variable environments lead to life-history trade-offs between investment in somatic growth and gonadal tissue, causing individuals to adopt specific behavioural tactics to attain reproduction. We investigated energy allocation in primary and secondary sexual traits in Atlantic salmon by estimating the life history characters (smolt size, sea age, first sea year growth rate by back-calculation of scales. Adult size increased with the fish sea age (years at sea and exerted a strong allometric effect on the energy investment pattern into secondary sexual traits. A compensatory mechanism at the ejaculate level is identified by which males investing less in secondary sexual traits produce ejaculates of higher quality. Distinct differences in investment into primary and secondary sexual traits between the fish that spent a single year in the sea before returning to the spawn (grilse and multi-sea-year adults were detected, indicating that their energy allocation strategy in reproductive effort reflects alternative developmental pathways. Grilse ejaculate investment depended more on the resource allocation, whereas multi-sea-year male ejaculate investment depended more on the resource acquisition.

  5. Individual protein balance strongly influences δ15N and δ13C values in Nile tilapia, Oreochromis niloticus

    Science.gov (United States)

    Gaye-Siessegger, Julia; Focken, Ulfert; Abel, Hansjörg; Becker, Klaus

    Although stable isotope ratios in animals have often been used as indicators of the trophic level and for the back-calculation of diets, few experiments have been done under standardized laboratory conditions to investigate factors influencing δ15N and δ13C values. An experiment using Nile tilapia [Oreochromis niloticus (L.)] was therefore carried out to test the effect of different dietary protein contents (35.4, 42.3, and 50.9%) on δ15N and δ13C values of the whole tilapia. The fish were fed the isoenergetic and isolipidic semi-synthetic diets at a relatively low level. δ15N and δ13C values of the lipid-free body did not differ between the fish fed the diets with different protein contents, but the trophic shift for N and C isotopes decreased with increasing protein accretion in the individual fish, for N from 6.5‰ to 4‰ and for C in the lipid-free body from 4‰ to 2.5‰. This is the first study showing the strong influence of the individual protein balance to the degree to which the isotopic signature of dietary protein was modified in tissue protein of fish. The extrapolation of the trophic level or the reconstruction of the diet of an animal from stable isotope ratios without knowledge of the individual physiological condition and the feeding rate may lead to erroneous results.

  6. Individual protein balance strongly influences delta15N and delta13C values in Nile tilapia, Oreochromis niloticus.

    Science.gov (United States)

    Gaye-Siessegger, Julia; Focken, Ulfert; Abel, Hansjörg; Becker, Klaus

    2004-02-01

    Although stable isotope ratios in animals have often been used as indicators of the trophic level and for the back-calculation of diets, few experiments have been done under standardized laboratory conditions to investigate factors influencing delta(15)N and delta(13)C values. An experiment using Nile tilapia [ Oreochromis niloticus (L.)] was therefore carried out to test the effect of different dietary protein contents (35.4, 42.3, and 50.9%) on delta(15)N and delta(13)C values of the whole tilapia. The fish were fed the isoenergetic and isolipidic semi-synthetic diets at a relatively low level. delta(15)N and delta(13)C values of the lipid-free body did not differ between the fish fed the diets with different protein contents, but the trophic shift for N and C isotopes decreased with increasing protein accretion in the individual fish, for N from 6.5 per thousand to 4 per thousand and for C in the lipid-free body from 4 per thousand to 2.5 per thousand. This is the first study showing the strong influence of the individual protein balance to the degree to which the isotopic signature of dietary protein was modified in tissue protein of fish. The extrapolation of the trophic level or the reconstruction of the diet of an animal from stable isotope ratios without knowledge of the individual physiological condition and the feeding rate may lead to erroneous results.

  7. Impacto da terapia anti-retroviral na magnitude da epidemia do HIV/AIDS no Brasil: diversos cenários Impact of antiretroviral therapy on the magnitude of the HIV/AIDS epidemic in Brazil: various scenarios

    Directory of Open Access Journals (Sweden)

    Maria Tereza S. Barbosa

    2003-04-01

    Full Text Available Neste trabalho, utilizaram-se os algoritmos EM e EMS aplicados ao método do Cálculo Retroativo para estimar a magnitude da epidemia do HIV no Brasil. Fazendo-se suposições a respeito do comportamento dos infectados, em relação à utilização da terapia combinada das drogas anti-retrovirais, construíram-se cinco cenários para a epidemia brasileira. O objetivo foi o de ilustrar os impactos que a utilização da terapia combinada das drogas anti-retrovirais possam estar tendo ou possam vir a ter na incubação do vírus e, por conseguinte, nas avaliações da epidemia realizadas a partir dos casos de Aids notificados.We applied the back-calculation method to estimate the magnitude of the HIV epidemic in Brazil, using the EM and EMS algorithms. Under certain assumptions regarding the behavior of infected patients towards combined antiretroviral therapy, we discuss five different scenarios applied to the Brazilian epidemic. Our objective was to illustrate the impact of combined antiretroviral treatment on the incubation period and thus on estimates of the size of the HIV-infected population, based on reported AIDS cases.

  8. Lake Roosevelt fisheries monitoring program

    International Nuclear Information System (INIS)

    The purpose of this study was to provide baseline data that could be used to evaluate the effectiveness of two kokanee salmon hatcheries that will produce 8 million kokanee salmon (Oncorhynchus nerka) fry or 3.2 million adults for stocking into Lake Roosevelt. The hatcheries will also produce 500,000 rainbow trout (Oncorhynchus mykiss) fingerlings to support the Lake Roosevelt net-pen programs. The baseline data will also be used to evaluate the effectiveness of the habitat improvement projects ongoing on a separate contract. At the present time, the principle sport fish in the reservoir are net-pen rainbow trout and walleye (Stizostedion vitreum). The objectives of the second year of the monitoring program were: (1) to determine angling pressure, catch per unit effort, total harvest and the economic value; (2) to determine relative abundance of fish species in the reservoir by conducting electrofishing and gillnet surveys at nine index stations during May, August, and October; (3) to determine growth rates of kokanee, rainbow trout, and walleye based upon backcalculations from scales collected during May, August and October and creel surveys; (4) to determine density, size, and biomass of zooplankton and how reservoir operations affect their population dynamics; (5) to determine feeding habits of kokanee, rainbow trout, and walleye and their preferred prey densities; and (6) to determine migration patterns of tagged walleye and net-pen rainbow trout. 118 refs., 20 figs., 98 tabs

  9. Continental scale inverse modeling of common organic water contaminants in European rivers

    International Nuclear Information System (INIS)

    The paper presents an analysis of measured riverine concentrations of 16 common organic water contaminants. From observed concentrations we back-calculate emissions and chemical half lives through a simple inverse model. The analysis does not allow identifying a single half life/emission factor combination, but a set of combinations which are Pareto-optimal (or “non-dominated”). The approach is shown to provide a rational basis for the screening of chemicals in rivers: with reference to the 16 chemicals considered here, estimated emission factors and half lives are consistent with the ones reported in other studies. For more precise estimates, prior knowledge about either emission factors or half lives is necessary. For the considered chemicals, loads to European seas can be subsequently estimated with an uncertainty usually within a factor of 2. The approach can be proposed for the inventorying of catchment-specific chemical pollutant emissions required for European environmental policies. - Highlights: ► Inverse modeling of emissions from river concentrations of common organic compounds. ► Fluxes estimated from observations through parameters half life and emission factor. ► The method is easy to include in any routine evaluation of monitoring results. ► It provides insights on chemical fate over large domains (as continental Europe). ► The method brings tightly together and interprets modeling and monitoring jointly. - An inverse model is applied to evaluate emission factors and loads to European seas of 16 water contaminants

  10. Analysis of root growth from a phenotyping data set using a density-based model.

    Science.gov (United States)

    Kalogiros, Dimitris I; Adu, Michael O; White, Philip J; Broadley, Martin R; Draye, Xavier; Ptashnyk, Mariya; Bengough, A Glyn; Dupuy, Lionel X

    2016-02-01

    Major research efforts are targeting the improved performance of root systems for more efficient use of water and nutrients by crops. However, characterizing root system architecture (RSA) is challenging, because roots are difficult objects to observe and analyse. A model-based analysis of RSA traits from phenotyping image data is presented. The model can successfully back-calculate growth parameters without the need to measure individual roots. The mathematical model uses partial differential equations to describe root system development. Methods based on kernel estimators were used to quantify root density distributions from experimental image data, and different optimization approaches to parameterize the model were tested. The model was tested on root images of a set of 89 Brassica rapa L. individuals of the same genotype grown for 14 d after sowing on blue filter paper. Optimized root growth parameters enabled the final (modelled) length of the main root axes to be matched within 1% of their mean values observed in experiments. Parameterized values for elongation rates were within ±4% of the values measured directly on images. Future work should investigate the time dependency of growth parameters using time-lapse image data. The approach is a potentially powerful quantitative technique for identifying crop genotypes with more efficient root systems, using (even incomplete) data from high-throughput phenotyping systems. PMID:26880747

  11. Fractured-rock permeability-versus-stress relationships from in situ experiments

    Science.gov (United States)

    Rutqvist, Jonny

    2016-04-01

    The purpose of this presentation is (1) to review field data on stress-induced permeability changes in fractured rock, (2) to describe back-analysis of fractured rock stress-versus-permeability relationships through model calibration against such field data, and (3) to discuss observations of chemically mediated fracture surface compaction and its effect on fractured rock permeability. Reviewed field data on stress-induced permeability changes, some of which are used for model calibration, includes in situ block experiments, borehole injection experiments, observations of depth dependent permeability, studies of excavation-induced changes in permeability around tunnels, and permeability changes associated with a large-scale rock mass heating experiment. It is suggested that model calibration of stress-versus-permeability relationships against field experiments involving simultaneously elevated stress and temperature may be strongly affected by additional temperature dependent fracture closure and fracture surface interlocking. This is a phenomenon that has been observed both in the lab and the field and has been described as thermal over-closure related to better fit of opposing fracture surfaces at high temperatures. The same phenomenon has also been described as chemically mediated fracture closure related to pressure solution of fracture surface asperities. The back-calculated stress-versus-permeability relationship may implicitly account for such effects, but the relative contribution of purely mechanical versus chemically mediated mechanical changes is difficult to isolate.

  12. Age and growth of round gobies in Lake Huron: Implications for food web dynamics

    Science.gov (United States)

    Duan, You J.; Madenjian, Charles P.; Xie, Cong X.; Diana, James S.; O'Brien, Timothy P.; Zhao, Ying M.; He, Ji X.; Farha, Steve A.; Huo, Bin

    2016-01-01

    Although the round goby (Neogobius melanostomus) has become established throughout the Laurentian Great Lakes, information is scarce on spatial variation in round goby growth between and within lakes. Based on a sample of 754 specimens captured in 2014, age, growth, and mortality of round gobies at four locations in Lake Huron were assessed via otolith analysis. Total length (TL) of round gobies ranged from 44 to 111 mm for Saginaw Bay, from 45 to 115 mm for Rockport, from 50 to 123 mm for Hammond Bay, and from 51 to 118 mm for Thunder Bay. Estimated ages of round gobies ranged from 2 to 5 years for Saginaw Bay, from 2 to 6 years for Rockport, and from 2 to 7 years for Hammond Bay and Thunder Bay. Sex-specific, body–otolith relationships were used to back-calculate total lengths at age, which were then fitted to von Bertalanffy growth models. For each sex, round goby growth showed significant spatial variation among the four locations within Lake Huron. At all four locations in Lake Huron, males grew significantly faster than females and attained a larger asymptotic length than females. Annual mortality rate estimates were high (62 to 85%), based on catch-curve analysis, suggesting that round gobies may be under predatory control in Lake Huron.

  13. Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

    Science.gov (United States)

    Hajlane, A.; Miettinen, A.; Madsen, B.; Beauson, J.; Joffe, R.

    2016-07-01

    The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight contents (5wt%, 10wt%, and 15wt% for untreated fibres, and 15wt% for treated fibres). The properties of fibres were measured by an automated single fibre tensile test method. Based on these results, the efficiency of the fibre treatment to improve fibre/matrix adhesion is evaluated, and the applicability of the method to measure the interfacial shear strength is discussed. The results are compared with data from previous work, and with other results from the literature.

  14. Age, growth and reproduction of the sand smelt Atherina boyeri Risso, 1810 in the Gomishan wetland - southeast Caspian Sea

    Science.gov (United States)

    Patimar, Rahman; Yousefi, Morteza; Hosieni, Seyyed Morteza

    2009-03-01

    A total of 2256 specimens of Atherina boyeri caught in Gomishan wetland (a marsh lagoon located at the southeast Caspian Sea) during spawning season from February to August 2007 were examined for life-history attributes. The population has a 4-year life cycle. Length-weight relationship was estimated as W = 0.0053TL 3.0181 for males and W = 0.0050TL 3.063 for females, being allometrically positive for both sexes. The von Bertalanffy growth function fitted to back-calculated size at age data was: Lt = 155.17[1 - exp - 0.28( t + 0.738)] and Lt = 162.77[1 - exp - 0.27( t + 0.727)] for males and females respectively. The sex ratio was 1:1.30 in favor of females. The reproductive season, evaluated from GSI, extended from March to July, with a peak in March. The average absolute and relative fecundities were 2976 eggs and 874 eggs g -1 of body weight respectively. The diameter of oocytes ranged from 0.03 to 0.20 mm with a mean value of 0.68. The life-history patterns of A. boyeri in the population under study imply that the population of this species in the southeast Caspian Sea differs markedly from those of other localities of its range distribution. The differences were thought to be due to differences in geographical locations.

  15. Critical Dimensionless Shields Values for Bankfull Flow

    Science.gov (United States)

    Bunte, K.; Abt, S. R.; Swingle, K. W.

    2009-12-01

    . Critical bankfull Shields values τ*cbf were back-calculated from the average largest collected bankfull bedload particle sizes. The most mobile study streams moved particles larger than the bed D50 at bankfull flow, and back-calculated values of τ*cbf were near 0.035. With increasing channel steepness, coarseness of the bed, and decreasing sediment supply, the average largest bankfull mobile particle size approached the bed D50 at several sites (τ*cbf near 0.055) and then dropped progressively further below the bed D50 for the steepest and coarsest streams. The associated values of τ*cbf increased from 0.1 to 0.7. The results show that critical dimensionless Shields values τ*cbf necessary to compute the average largest bankfull mobile particle size span a wider range than previously recognized. τ*cbf increases from near 0.035 for very mobile, coarse gravel-bed streams with plane-bed/pool-riffle morphologies to nearly 0.7 for step-pool streams in which particle mobility is hampered by the structural stability of the bed.

  16. Age and growth estimation of bigeye tuna, Thunnus obesus (Teleostei: Scombridae in the southwestern Atlantic

    Directory of Open Access Journals (Sweden)

    Paulo Duarte-Neto

    2012-01-01

    Full Text Available The purpose of the current study was to supply the first information on age and growth for Thunnus obesus caught in the equatorial south-western Atlantic using dorsal spines, an approach that has been successfully employed for ageing tuna species. The study was conducted using a multi-model inference based on information theory for back-calculated and observed length-at-age data. Uncertainty associated with the parameter estimation was verified and results were compared to other accounts on the species, considering both the statistical and methodological contexts. Samples were collected in Natal city (Rio Grande do Norte State, Brazil from February 1999 to January 2000, of tuna vessels and from surveys, aimed at providing information on the Brazilian Exclusive Economic Zone (EEZ in the area around São Pedro and São Paulo Archipelago. Validation using marginal increment indicated that one ring is deposited per year. Mean length-at-age ranged of 54.3 to 177.5 cm (fork length for ages 1 to 9 years. Von Bertalanffy, Richards, and Gompertz models were considered suitable for the bigeye tuna. Hence, the model-averaged asymptotic length ¯L∞ was estimated. The averaged model generated in the present study by back-calculation was considered appropriate for describing the growth of T. obesus.A proposta do presente estudo foi fornecer a primeira informação sobre idade e crescimento de Thunnus obesus, capturado no Atlântico sudoeste equatorial usando espinhos dorsais, uma abordagem que tem sido utilizada com sucesso na determinação de idade de espécies de atuns. O estudo foi conduzido usando uma inferência de multi-modelos baseada na teoria de informação avaliada para dados de comprimento por idade retrocalculados e observados. Incertezas associadas aos parâmetros foram verificadas e os resultados foram comparados aos de outros estudos realizados para esta espécie, considerando os contextos estatísticos e metodológicos. As amostras foram

  17. Desenvolvimento de um equipamento de grandes dimensões para análise de estruturas de pavimentos

    Directory of Open Access Journals (Sweden)

    Francis Massashi Kakuda

    2011-04-01

    means of backcalculation, the determination of the materials resilient modulus. In a preliminary analysis, the equipment showed a good operation, attended to the expectations and the transducers supplied measures with the required precision. The backcalculation results were compatible with those obtained from cyclic triaxial tests and those observed in similar field conditions.

  18. Analysis of cocaine and nicotine metabolites in wastewater by liquid chromatography-tandem mass spectrometry. Cross abuse index patterns on a major community.

    Science.gov (United States)

    Lopes, Alvaro; Silva, Nuno; Bronze, M R; Ferreira, João; Morais, José

    2014-07-15

    A method based on sample preparation by solid phase extraction and analysis by liquid chromatography and mass spectrometry was validated and used for simultaneous analysis of cocaine, benzoylecgonine and cotinine in samples collected at the major wastewater treatment plant in the city of Lisbon. The aim was to estimate the consumption of both cocaine and nicotine in this community and establish an index involving both drugs supported by the relevance of nicotine as a significant anthropogenic marker. The study was made on two different weekdays during a month in order to evaluate patterns of consumption outside weekends. Cocaine and nicotine ingestion levels were back-calculated and expressed as mass of pure drugs consumed per day and per 1000 inhabitants (mean: 0.604 g and 5.860 g respectively). Cocaine was also expressed on the basis of local drug purity levels (33.7%) with a corresponding increase on dose assessments, and community drug abuse profiles. The authors sustain that this approach should always be included in drug studies of this kind allowing a better drug abuse assessment. No significant different patterns of consumption were obtained during the working days studied with the exception of one case coincident with a national holiday that showed an increased typical profile found on other non-working day studies, namely weekends. A fairly significant relationship was found between nicotine and cocaine consumption that should be further evaluated in future studies. Pharmacokinetic considerations were made and proposed for cocaine assessment based on the impact on back calculations after common simultaneous consumption of cocaine and ethanol. PMID:24200094

  19. Quantitative analysis of maytansinoid (DM1) in human serum by on-line solid phase extraction coupled with liquid chromatography tandem mass spectrometry - Method validation and its application to clinical samples.

    Science.gov (United States)

    Heudi, Olivier; Barteau, Samuel; Picard, Franck; Kretz, Olivier

    2016-02-20

    A sensitive and specific method was developed and validated for the quantitation of maytansinoid (DM1) in human serum using on-line solid phase extraction (SPE)-liquid chromatography-tandem mass spectrometry (LC-MS/MS). Because DM1 contains a free thiol moiety, likely to readily dimerize or react with other thiol-containing molecules in serum, samples were pre-treated with a reducing agent [tris (2-carboxyethyl) phosphine] (TCEP) and further blocked with N-ethylmaleimide (NEM). The resulting samples were diluted with acetonitrile prior to the on-line solid phase extraction (SPE) on a C18 cartridge. A C18 (150×4.6mm ID 3μm particle size) column was used for chromatographic separation with a 10.0min HPLC gradient and DM1-NEM was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. DM1 concentrations were back-calculated from DM1-NEM amount found in the human serum samples. The quantitation range of the method was 0.200-200ng/mL when using 0.25mL serum. Within-run day precisions (n=6) were 0.9-4.4% and between-run day (3 days runs; n=18) precisions 2.5-5.6%. Method biases were between 3.5-14.5% across the whole calibration range. DM1-NEM exhibited sufficiently stability under all relevant analytical conditions and no DM1 losses from the ADC were observed. Finally, the assay was used for DM1 determination in human serum concentration after the intravenous administration of an investigational antibody drug conjugate (ADC) containing DM1 as payload. PMID:26771131

  20. Determination of oxygen-18 content of water by hydrolysis of phosphorus pentachloride and measurment by gas chromatography and mass spectrometry with selected ion monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.; Minard, R.D.

    1980-03-01

    Water is one of the most difficult chemicals in which to measure /sup 18/0 content. The classical method consisted of equilibrating a sample of water with a known amount of CO/sub 2/, followed by the determination of the /sup 18/0 content of the CO/sub 27/ and back-calculating via the known equilibrium constant for this reaction. Another method is the pyrolysis of an H/sub 2/0 sample with guanidine hydrochloride. The CO/sub 2/ produced from pyrolysis contains oxygen with the same /sup 18/0 content as that of the original H/sub 2/0 sample. The advantage of this method over the 2 previously mentioned is that it does not require the technology associated with handling gaseous samples. A sample of (/sup 18/0) H/sub 2/0 was placed in a PCl/sub 5/ reaction vessel. The phosphoric acid resulting from complete hydrolysis of the PCl/sub 5/ was methyl esterified by adding one or two drops of methanol, followed by an ethereal solution of diazomethane. The solutions of trimethyl phosphate were then concentrated to minimal volume by evaporating the solvent in a stream of dry N/sub 2/, and diluting with CHCl/sub 3/. The electron impact mass spectrum of trimethyl phosphate observed was consistent with that reported by Bafus et al. Basing the final calculated /sup 18/0 content on the measurement of several ion intensities results in a significant decrease in the sensitivity of the result to errors in the measurement of any one ion intensity. Because the hydrolysis of PCl/sub 5/ introduces four oxygens from water into the H/sub 3/P0/sub 4/, a statistical distribtuion of the five isotopomers of H/sub 3/P0/sub 4/ should be obtained, assuming no isotope effects in the PCl/sub 5/ hydrolysis. 2 tables. (DP)

  1. Using drift nets to capture early life stages and monitor spawning of the yangtze river chinese sturgeon (Acipenser sinensis)

    Science.gov (United States)

    Wei, Q.W.; Kynard, B.; Yang, D.G.; Chen, X.H.; Du, H.; Shen, L.; Zhang, H.

    2009-01-01

    A sampling system for capturing sturgeon eggs using a D-shaped bottom anchored drift net was used to capture early life stages (ELS) of Chinese sturgeon, Acipenser sinensis, and monitor annual spawning success at Yichang on the Yangtze River, 1996-2004, before and just after the Three Gorges Dam began operation. Captured were 96 875 ELS (early life stages: eggs, yolk-sac larvae = eleuthero embryos, and larvae); most were eggs and only 2477 were yolk-sac larvae. Most ELS were captured in the main river channel and inside the bend at the Yichang spawning reach. Yolk-sac larvae were captured for a maximum of 3 days after hatching began, indicating quick dispersal downstream. The back-calculated day of egg fertilization over the eight years indicated a maximum spawning window of 23 days (20 October-10 November). Spawning in all years was restricted temporally, occurred mostly at night and during one or two spawning periods, each lasting several days. The brief temporal spawning window may reduce egg predation by opportunistic predators by flooding the river bottom with millions of eggs. During 1996-2002, the percentage of fertilized eggs in an annual 20-egg sample was between 63.5 to 94.1%; however, in 2003 the percentage fertilized was only 23.8%. This sudden decline may be related to the altered environmental conditions at Yichang caused by operation of the Three Gorges Dam. Further studies are needed to monitor spawning and changes in egg fertilization in this threatened population. ?? 2009 Blackwell Verlag GmbH.

  2. High performance ZIF-8/6FDA-DAM mixed matrix membrane for propylene/propane separations

    KAUST Repository

    Zhang, Chen

    2012-02-01

    We report significantly enhanced propylene/propane (C 3H 6/C 3H 8) selectivity in mixed matrix membranes fabricated using 6FDA-DAM polyimide and a zeolitic imidazolate framework (ZIF-8). Equilibrium isotherms and sorption kinetics of C 3H 6 and C 3H 8 at 35°C were studied on a 200nm commercially available ZIF-8 sample produced by BASF. Mixed matrix dense films were formed with 6FDA-DAM and 200nm BASF ZIF-8 particles. SEM imaging showed generally good adhesion between the ZIF-8 and 6FDA-DAM without the need for surface-treating ZIF-8. Pure gas permeation showed significantly enhanced mixed matrix ZIF-8/6FDA-DAM membrane C 3H 6/C 3H 8 separation performance over the pure 6FDA-DAM membrane performance. A C 3H 6 permeability of 56.2Barrer and C 3H 6/C 3H 8 ideal selectivity of 31.0 was found in ZIF-8/6FDA-DAM mixed matrix membrane with 48.0wt% ZIF-8 loading, which are 258% and 150% higher than the pure 6FDA-DAM membrane, respectively for permeability and selectivity. Permeation properties of C 3H 6 and C 3H 8 in ZIF-8 were back-calculated by the Maxwell model for composite permeability using pure gas permeation data, leading to a C 3H 6 permeability of 277Barrer and C 3H 6/C 3H 8 selectivity of 122. Mixed gas permeation also verified that selectivity enhancements were achievable in mixed gas environment by ZIF-8. © 2011 Elsevier B.V.

  3. (137)Cs distributions in soil and trees in forest ecosystems after the radioactive fallout - Comparison study between southern Finland and Fukushima, Japan.

    Science.gov (United States)

    Pumpanen, Jukka; Ohashi, Mizue; Endo, Izuki; Hari, Pertti; Bäck, Jaana; Kulmala, Markku; Ohte, Nobuhito

    2016-09-01

    The nuclear accidents at Chernobyl and Fukushima released large amounts of (137)Cs radionuclides into the atmosphere which spread over large forest areas. We compared the (137)Cs concentration distribution in different parts of two coniferous forest ecosystems (needle litter, stems and at different depths in the soil) over short and long term periods in Finland and Japan. We also estimated the change in (137)Cs activity concentrations in needle and soil between 1995 and 2013 in Southern Finland based on the back-calculated (137)Cs activity concentrations. We hypothesized that if the (137)Cs activity concentrations measured in 1995 and 2013 showed a similar decline in concentration, the (137)Cs activity concentration in the ecosystem was already stable in 1995. But if not, the (137)Cs activity concentrations were still changing in 2013. Our results showed that the vertical distribution of the (137)Cs fallout in the soil was similar in Hyytiälä and Fukushima. The highest (137)Cs concentrations were observed in the uppermost surface layers of the soil, and they decreased exponentially deeper in the soil. We also observed that (137)Cs activity concentrations estimated from the samples in 1995 and 2013 in Finland showed different behavior in the surface soil layers compared to the deep soil layer. These results suggested that the (137)Cs nuclei were still mobile in the surface soil layers 27 years after the accident. Our results further indicated that, in the aboveground parts of the trees, the (137)Cs concentrations were much closer to steady-state when compared to those of the surface soil layers based on the estimated declining rates of (137)Cs concentration activity in needles which were similar in 1995 and 2013. Despite its mobility and active role in the metabolism of trees, the (137)Cs remains in the structure of the trees for decades, and there is not much exchange of (137)Cs between the heartwood and surface layers of the stem. PMID:27158060

  4. Quantification of Age-Related Tissue-Level Failure Strains of Rat Femoral Cortical Bones Using an Approach Combining Macrocompressive Test and Microfinite Element Analysis.

    Science.gov (United States)

    Fan, Ruoxun; Gong, He; Zhang, Rui; Gao, Jiazi; Jia, Zhengbin; Hu, Yanjuan

    2016-04-01

    Bone mechanical properties vary with age; meanwhile, a close relationship exists among bone mechanical properties at different levels. Therefore, conducting multilevel analyses for bone structures with different ages are necessary to elucidate the effects of aging on bone mechanical properties at different levels. In this study, an approach that combined microfinite element (micro-FE) analysis and macrocompressive test was established to simulate the failure of male rat femoral cortical bone. Micro-FE analyses were primarily performed for rat cortical bones with different ages to simulate their failure processes under compressive load. Tissue-level failure strains in tension and compression of these cortical bones were then back-calculated by fitting the experimental stress-strain curves. Thus, tissue-level failure strains of rat femoral cortical bones with different ages were quantified. The tissue-level failure strain exhibited a biphasic behavior with age: in the period of skeletal maturity (1-7 months of age), the failure strain gradually increased; when the rat exceeded 7 months of age, the failure strain sharply decreased. In the period of skeletal maturity, both the macro- and tissue-levels mechanical properties showed a large promotion. In the period of skeletal aging (9-15 months of age), the tissue-level mechanical properties sharply deteriorated; however, the macromechanical properties only slightly deteriorated. The age-related changes in tissue-level failure strain were revealed through the analysis of male rat femoral cortical bones with different ages, which provided a theoretical basis to understand the relationship between rat cortical bone mechanical properties at macro- and tissue-levels and decrease of bone strength with age. PMID:26902102

  5. Recently deglaciated high-altitude soils of the Himalaya: diverse environments, heterogenous bacterial communities and long-range dust inputs from the upper troposphere.

    Directory of Open Access Journals (Sweden)

    Blaz Stres

    Full Text Available BACKGROUND: The Himalaya with its altitude and geographical position forms a barrier to atmospheric transport, which produces much aqueous-particle monsoon precipitation and makes it the largest continuous ice-covered area outside polar regions. There is a paucity of data on high-altitude microbial communities, their native environments and responses to environmental-spatial variables relative to seasonal and deglaciation events. METHODOLOGY/PRINCIPAL FINDINGS: Soils were sampled along altitude transects from 5000 m to 6000 m to determine environmental, spatial and seasonal factors structuring bacterial communities characterized by 16 S rRNA gene deep sequencing. Dust traps and fresh-snow samples were used to assess dust abundance and viability, community structure and abundance of dust associated microbial communities. Significantly different habitats among the altitude-transect samples corresponded to both phylogenetically distant and closely-related communities at distances as short as 50 m showing high community spatial divergence. High within-group variability that was related to an order of magnitude higher dust deposition obscured seasonal and temporal rearrangements in microbial communities. Although dust particle and associated cell deposition rates were highly correlated, seasonal dust communities of bacteria were distinct and differed significantly from recipient soil communities. Analysis of closest relatives to dust OTUs, HYSPLIT back-calculation of airmass trajectories and small dust particle size (4-12 µm suggested that the deposited dust and microbes came from distant continental, lacustrine and marine sources, e.g. Sahara, India, Caspian Sea and Tibetan plateau. Cyanobacteria represented less than 0.5% of microbial communities suggesting that the microbial communities benefitted from (codeposited carbon which was reflected in the psychrotolerant nature of dust-particle associated bacteria. CONCLUSIONS/SIGNIFICANCE: The spatial

  6. Age, growth and reproduction of Sarcocheilichthys nigripinnis from the Qingyi Stream in the Huangshan Mountains%Age,growth and reproduction of Sarcocheilichthys nigripinnis from the Qingyi Stream in the Huangshan Mountains

    Institute of Scientific and Technical Information of China (English)

    Yunzhi YAN; Yinsheng XU; Ling CHU; Shan HE; Yifeng CHEN

    2012-01-01

    Identifying the life-history strategies of fish and their associations with the surrounding environment is the basic foundation in the conservation and sustainable utilization of fish species.We examined the age,growth,and reproduction of Sarcocheilichthys nigripinnis using 352 specimens collected monthly from May 2009 to April 2010 in the Qingyi Stream.We found the sex ratio of this study population was 0.58:1 (female:male),significantly different from expected 1:1.Females and males both comprised four age groups.The annuli on the scales were formed during February and March.No obvious between-sex difference was observed in length-weight and length-scale-radius relationships.The total length in back-calculation significantly increased with age for both sexes,but did not differ significantly at each age between the two sexes.An inflection point was observed in the growth curves given by the yon Bertalanffy growth function for total weight.At this inflection point,fish were 3.95 years.Both sexes reach their 50% sex maturity at age 2,when females and males were 94.7 mm and 103.0 mm total length.The temporal pattern of the gonado-somatic index corresponded to a spawning period that occurred from April through July.The non-synchronicity of egg diameter in each mature ovary during the breeding period suggested these fish may be batch spawners.The absolute fecundity increased significantly with total length and weight,whereas no significant correlation was observed between the relative fecundity and body size.

  7. Combining Spatial Models for Shallow Landslides and Debris-Flows Prediction

    Directory of Open Access Journals (Sweden)

    Eurípedes Vargas do Amaral

    2013-05-01

    Full Text Available Mass movements in Brazil are common phenomena, especially during strong rainfall events that occur frequently in the summer season. These phenomena cause losses of lives and serious damage to roads, bridges, and properties. Moreover, the illegal occupation by slums on the slopes around the cities intensifies the effect of the mass movement. This study aimed to develop a methodology that combines models of shallow landslides and debris-flows in order to create a map with landslides initiation and debris-flows volume and runout distance. The study area comprised of two catchments in Rio de Janeiro city: Quitite and Papagaio that drained side by side the west flank of the Maciço da Tijuca, with an area of 5 km2. The method included the following steps: (a location of the susceptible areas to landslides using SHALSTAB model; (b determination of rheological parameters of debris-flow from the back-analysis technique; and (c combination of SHALSTAB and FLO-2D models to delineate the areas more susceptible to mass movements. These scenarios were compared with the landslide and debris-flow event of February 1996. Many FLO-2D simulations were exhaustively made to estimate the rheological parameters from the back-analysis technique. Those rheological coefficients of single simulation were back-calculated by adjusting with area and depth of the debris-flow obtained from field data. The initial material volume in the FLO-2D simulations was estimated from SHALSTAB model. The combination of these two mathematical models, SHALSTAB and FLO-2D, was able to predict both landslides and debris-flow events. Such procedures can reduce the casualties and property damage, delineating hazard areas, to estimate hazard intensities for input into risk studies providing information for public policy and planning.

  8. Age, growth, and gonadal characteristics of adult bighead carp, Hypophthalmichthys nobilis, in the lower Missouri River

    Science.gov (United States)

    Schrank, S.J.; Guy, C.S.

    2002-01-01

    Bighead carp were introduced into Arkansas in 1973 to improve water clarity in production ponds. Bighead carp subsequently escaped aquaculture facilities in the early 1980's and dispersed into the Mississippi and Missouri rivers. The first documentation of bighead carp reproduction in the Mississippi River system was in 1989. The population has increased in the Missouri River as is evident in their increased proportion in the commercial harvest since 1990. The effect of this exotic planktivore on native ecosystems of the U.S. has not been examined. Basic biological data on bighead carp Hypophthalmichthys nobilis in the Missouri River are needed to predict potential ecological problems and provide a foundation for manipulative studies. The objectives of this study were to assess age, growth, and gonadal characteristics of bighead carp in the Missouri River. Adult bighead carp in our sample varied from age 3 to age 7 and length varied from 475 to 1050 mm. There was a large variation in length at age, and overall bighead carp exhibited fast growth. For example, mean back-calculated length at age 3 was 556 mm. The sample was dominated by bighead carp from the 1994 year class. There was no difference in gonad development (i.e., gonadal somatic index, egg diameter) between winter and spring samples. Length of male bighead carp and GSI were not significantly correlated; however, females exhibited a positive linear relationship between length and GSI. In each ovary, egg diameter frequencies exhibited a bimodal distribution, indicating protracted spawning. Mean fecundity was 226 213, with a maximum fecundity of 769 964. Bighead carp in the Missouri River have similar life history characteristics to Asian and European populations. They have become well established in the Missouri River and it is likely that dispersal and population density will increase.

  9. Probing the conformation of FhaC with small-angle neutron scattering and molecular modeling.

    Science.gov (United States)

    Gabel, Frank; Lensink, Marc F; Clantin, Bernard; Jacob-Dubuisson, Françoise; Villeret, Vincent; Ebel, Christine

    2014-07-01

    Probing the solution structure of membrane proteins represents a formidable challenge, particularly when using small-angle scattering. Detergent molecules often present residual scattering contributions even at their match point in small-angle neutron scattering (SANS) measurements. Here, we studied the conformation of FhaC, the outer-membrane, β-barrel transporter of the Bordetella pertussis filamentous hemagglutinin adhesin. SANS measurements were performed on homogeneous solutions of FhaC solubilized in n-octyl-d17-βD-glucoside and on a variant devoid of the α helix H1, which critically obstructs the FhaC pore, in two solvent conditions corresponding to the match points of the protein and the detergent, respectively. Protein-bound detergent amounted to 142 ± 10 mol/mol as determined by analytical ultracentrifugation. By using molecular modeling and starting from three distinct conformations of FhaC and its variant embedded in lipid bilayers, we generated ensembles of protein-detergent arrangement models with 120-160 detergent molecules. The scattered curves were back-calculated for each model and compared with experimental data. Good fits were obtained for relatively compact, connected detergent belts, which occasionally displayed small detergent-free patches on the outer surface of the β barrel. The combination of SANS and modeling clearly enabled us to infer the solution structure of FhaC, with H1 inside the pore as in the crystal structure. We believe that our strategy of combining explicit atomic detergent modeling with SANS measurements has significant potential for structural studies of other detergent-solubilized membrane proteins. PMID:24988353

  10. Stay off the motorway: Resolving the pre-recruitment life history dynamics of the European anchovy in the SW Mediterranean through a spatially-explicit individual-based model (SEIBM)

    Science.gov (United States)

    Catalán, Ignacio A.; Macías, Diego; Solé, Jordi; Ospina-Álvarez, Andrés; Ruiz, Javier

    2013-04-01

    We explore the underlying mechanisms of the early life history dynamics of the European anchovy, Engraulis encrasicolus, in the SW Mediterranean. By using a 3D ROMS hydrodynamic model coupled to an individual-based model (IBM) of the larval stages of the European anchovy, we tested the following hypotheses: (1) the plausible effective spawning zones (those generating late larvae to the known nursery grounds) are mainly found in the vicinity of Malaga Bay, as suggested by published empirical data; (2) the observed, back-calculated growth of larvae sampled in the nursery grounds can be reasonably simulated by a simple temperature-dependent growth model; and (3) the inclusion of biological behavior in the IBM significantly improves the match between the observed and modeled late-larval recruitment and/or growth patterns. We performed simulations for the peak spawning season in 2008, for which survey data were available, and an average climatological run. Hypothesis 1 was accepted, whereas hypothesis 2 resulted in a good imitation of anchovy growth only after 10 days post-hatch. The inclusion of an empirically derived equation for egg buoyancy in the model (hypothesis 3) resulted in a slight improvement of the model of late-larval recruitment patterns. Finally, our model was used to explore possible retention-based nursery areas in the whole Alboran Sea. Our simulations showed to agree well with the existing data both in the European and in the African coast and confer the physics a dominant role in shaping the spatial dynamics of early life stages of anchovy in the area.

  11. Vertebral morphology, dentition, age, growth, and ecology of the large lamniform shark Cardabiodon ricki

    Directory of Open Access Journals (Sweden)

    Michael G. Newbrey

    2015-12-01

    Full Text Available Cardabiodon ricki and Cardabiodon venator were large lamniform sharks with a patchy but global distribution in the Cenomanian and Turonian. Their teeth are generally rare and skeletal elements are less common. The centra of Cardabiodon ricki can be distinguished from those of other lamniforms by their unique combination of characteristics: medium length, round articulating outline with a very thick corpus calcareum, a corpus calcareum with a laterally flat rim, robust radial lamellae, thick radial lamellae that occur in low density, concentric lamellae absent, small circular or subovate pores concentrated next to each corpus calcareum, and papillose circular ridges on the surface of the corpus calcareum. The large diameter and robustness of the centra of two examined specimens suggest that Cardabiodon was large, had a rigid vertebral column, and was a fast swimmer. The sectioned corpora calcarea show both individuals deposited 13 bands (assumed to represent annual increments after the birth ring. The identification of the birth ring is supported in the holotype of Cardabiodon ricki as the back-calculated tooth size at age 0 is nearly equal to the size of the smallest known isolated tooth of this species. The birth ring size (5–6.6 mm radial distance [RD] overlaps with that of Archaeolamna kopingensis (5.4 mm RD and the range of variation of Cretoxyrhina mantelli (6–11.6 mm RD from the Smoky Hill Chalk, Niobrara Formation. The revised, reconstructed lower jaw dentition of the holotype of Cardabiodon ricki contains four anterior and 12 lateroposterior files. Total body length is estimated at 5.5 m based on 746 mm lower jaw bite circumference reconstructed from associated teeth of the holotype.

  12. Magic Angle Spinning NMR Structure Determination of Proteins from Pseudocontact Shifts

    KAUST Repository

    Li, Jianping

    2013-06-05

    Magic angle spinning solid-state NMR is a unique technique to study atomic-resolution structure of biomacromolecules which resist crystallization or are too large to study by solution NMR techniques. However, difficulties in obtaining sufficient number of long-range distance restraints using dipolar coupling based spectra hamper the process of structure determination of proteins in solid-state NMR. In this study it is shown that high-resolution structure of proteins in solid phase can be determined without the use of traditional dipolar-dipolar coupling based distance restraints by combining the measurements of pseudocontact shifts (PCSs) with Rosetta calculations. The PCSs were generated by chelating exogenous paramagnetic metal ions to a tag 4-mercaptomethyl-dipicolinic acid, which is covalently attached to different residue sites in a 56-residue immunoglobulin-binding domain of protein G (GB1). The long-range structural restraints with metal-nucleus distance of up to ∼20 Å are quantitatively extracted from experimentally observed PCSs, and these are in good agreement with the distances back-calculated using an X-ray structure model. Moreover, we demonstrate that using several paramagnetic ions with varied paramagnetic susceptibilities as well as the introduction of paramagnetic labels at different sites can dramatically increase the number of long-range restraints and cover different regions of the protein. The structure generated from solid-state NMR PCSs restraints combined with Rosetta calculations has 0.7 Å root-mean-square deviation relative to X-ray structure. © 2013 American Chemical Society.

  13. Of travertine and time: otolith chemistry and microstructure detect provenance and demography of endangered humpback chub in Grand Canyon, USA

    Science.gov (United States)

    Limburg, Karin E.; Hayden, Todd A.; Pine, William E.; Yard, Michael D.; Kozdon, Reinhard; Valley, John W.

    2013-01-01

    We developed a geochemical atlas of the Colorado River in Grand Canyon and in its tributary, the Little Colorado River, and used it to identify provenance and habitat use by Federally Endangered humpback chub, Gila cypha. Carbon stable isotope ratios (δ13C) discriminate best between the two rivers, but fine scale analysis in otoliths requires rare, expensive instrumentation. We therefore correlated other tracers (SrSr, Ba, and Se in ratio to Ca) to δ13C that are easier to quantify in otoliths with other microchemical techniques. Although the Little Colorado River’s water chemistry varies with major storm events, at base flow or near base flow (conditions occurring 84% of the time in our study) its chemistry differs sufficiently from the mainstem to discriminate one from the other. Additionally, when fish egress from the natal Little Colorado River to the mainstem, they encounter cold water which causes the otolith daily growth increments to decrease in size markedly. Combining otolith growth increment analysis and microchemistry permitted estimation of size and age at first egress; size at first birthday was also estimated. Emigrants < 1 year old averaged 51.2 ± 4.4 (SE) days and 35.5 ± 3.6 mm at egress; older fish that had recruited to the population averaged 100 ± 7.8 days old and 51.0 ± 2.2 mm at egress, suggesting that larger, older emigrants recruit better. Back-calculated size at age 1 was unimodal and large (78.2 ± 3.3 mm) in Little Colorado caught fish but was bimodally distributed in Colorado mainstem caught fish (49.9 ± 3.6 and 79 ± 4.9 mm) suggesting that humpback chub can also rear in the mainstem. The study demonstrates the coupled usage of the two rivers by this fish and highlights the need to consider both rivers when making management decisions for humpback chub recovery.

  14. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    Energy Technology Data Exchange (ETDEWEB)

    Danko, G.; Birkholzer, J.T.; Bahrami, D.; Halecky, N.

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  15. Determination of oxidant exposure during ozonation of secondary effluent to predict contaminant removal.

    Science.gov (United States)

    Zucker, Ines; Avisar, Dror; Mamane, Hadas; Jekel, Martin; Hübner, Uwe

    2016-09-01

    The use of kinetic models to predict oxidation performance in wastewater is limited due to fast ozone depletion during the first milliseconds of the reaction. This paper introduces the Quench Flow Module (QFM), a bench-scale experimental technique developed to measure the first 5-500 milliseconds of ozone depletion for accurate determination of ozone exposure in wastewater-ozonation processes. Calculated ozone exposure in QFM experiments was up to 24% lower than in standard batch experiments, strongly depending on the initial sampling point for measurement in batch experiments. However, oxidation rates of slowly- and moderately-reacting trace organic compounds (TrOCs) were accurately predicted from batch experiments based on integration of ozone depletion and removal of an ozone-resistant probe compound to calculate oxidant exposures. An alternative concept, where ozone and hydroxyl radical exposures are back-calculated from the removal of two probe compounds, was tested as well. Although the QFM was suggested to be an efficient mixing reactor, ozone exposure ranged over three orders of magnitude when different probe compounds reacting moderately with ozone were used for the calculation. These effects were beyond uncertainty ranges for apparent second order rate constants and consistently observed with different ozone-injection techniques, i.e. QFM, batch experiments, bubble columns and venturi injection. This indicates that previously suggested mixing effects are not responsible for the difference and other still unknown factors might be relevant. Results furthermore suggest that ozone exposure calculations from the relative residual concentration of a probe compound are not a promising option for evaluation of ozonation of secondary effluents. PMID:27232995

  16. Research on Fatigue Curves for Pre-corroded Aircraft Structures%飞机结构预腐蚀疲劳曲线研究

    Institute of Scientific and Technical Information of China (English)

    王忠波; 刘文珽; 贺小帆

    2004-01-01

    为评估地面停放预腐蚀对飞机结构疲劳寿命的影响,采用二元线性回归方法建立了一种新的预腐蚀疲劳曲线幂函数表达式.该曲线的指数为常量而对数截距是预腐蚀时间的线性函数.这两个特性使得曲线形式简单,参数几何、工程含义明确,并易于工程应用.通过寿命反推建立了参数修正的三参数预腐蚀疲劳曲线,该曲线已成功用于飞机结构腐蚀条件下的疲劳寿命估算.%To quantitatively evaluate the effects of corrosion during grounding on fatigue life of aircraft structures, a new power equation is proposed using two-variable linear regression method. That the slope is a constant and the logarithmic intercept is a linear function of pre-corrosion time makes this equation advantageous: it has a simple form, its parameters have unambiguous technical and geometrical meanings, and it facilitates engineering applications. Three-parameter equations after pre-corrosion are obtained from back-calculation of fatigue limits, which have been successfully used to predict safe life of aircraft structures in corrosive environment.

  17. In situ geomechanics: Climax granite, Nevada Test Site

    International Nuclear Information System (INIS)

    The in situ modulus of the Climax granite in the Spent Fuel Test (SFT-C) area of the Nevada Test Site was estimated using six different approaches. Our best estimate of field modulus as E/sub f/ = 26 GPa was obtained from a comparison of the various approaches. A best estimate of laboratory modulus acquired by comparing three different sources was E/sub l/ = 70 GPa. Therefore, the modulus reduction factor for the Climax granite appears to be E/sub f//E/sub l/ = 0.37. In turn, our estimate of in situ rock-mass deformability was used to back-calculate in situ values for the normal stiffness of the granite joints. Our analysis of former stress measurements by the US Geological Survey (USGS) shows that the horizontal stresses in the vicinity of SFT-C vary greatly with azimuth. An unexplained feature of the stresses at SFT-C is the fact that the vertical stress appears to be only 65 to 75% of the calculated lithostatic burden. From the three-dimensional stress ellipsoid at mid-length in the tunnels, assuming a plane strain condition, we were able to estimate an in situ Poisson's ratio of the rock mass as ν = 0.246. Two other techniques were applied in an attempt to measure the stresses around the SFT-C heater and canister drifts: the undercoring method and the borehole jack fracturing approach. The former technique appears to have given reasonable estimates of tangential stresses in the roof of the heater drifts; the latter appears to give low results for stresses in the pillars. Specific recommendations are made for future tests to further characterize the mechanical properties of the Climax granite and the in situ stresses at SFT-C

  18. Natural growth, otolith shape and diet analyses of Odontesthes nigricans Richardson (Atherinopsidae) from southern Patagonia

    Science.gov (United States)

    Lattuca, M. E.; Lozano, I. E.; Brown, D. R.; Renzi, M.; Luizon, C. A.

    2015-12-01

    Age and growth, otolith shape and diet of Odontesthes nigricans were analysed in order to provide an insight into the life history of the species and furthermore, to assess their possible use as a tool for discriminating silverside populations from the South Atlantic Ocean (Punta María) and Beagle Channel waters (Varela Bay). The age and growth analysis was performed by counting daily increments and annual marks in sagittae otoliths. Length-at-age data of individuals Gompertz model (SLt = 6.22 exp 2.45 [1-exp (-0.02t)]), which provided an excellent description of the pattern of daily growth for O. nigricans juveniles from Varela Bay. The spawning period was also assessed through back-calculation of hatching dates and it extended from November to February. The count of annual marks in larger individuals identified 7 year classes (0+ to 6+) in Varela Bay and 6 year classes (0+ to 5+) in Punta María. The von Bertalanffy growth model explained more than 95% of the growth patterns observed in O. nigricans from Varela Bay (SLt = 245.49 [1 - exp -0.24(t+0.46)]) and Punta María (SLt = 345.09 [1 - exp -0.15(t+0.31)]). Particularly, k and SL∞ varied significantly between sampling sites; reaching Punta María a larger SL∞ value with a lower k. Otolith shape variation was also explored using elliptical Fourier analysis and it showed significant differences between Varela Bay and Punta María populations. Furthermore, gut content analysis characterized O. nigricans as an invertebrate predator, being benthic organisms the most important components of its diet, which also showed significant site dependence. The use of all these analyses contributed to a holistic approach which maximized the likelihood of correctly identifying both O. nigricans populations in the southernmost limit of the species distribution.

  19. Collision risk in white-tailed eagles. Modelling kernel-based collision risk using satellite telemetry data in Smoela wind-power plant

    Energy Technology Data Exchange (ETDEWEB)

    May, Roel; Nygaard, Torgeir; Dahl, Espen Lie; Reitan, Ole; Bevanger, Kjetil

    2011-05-15

    Large soaring birds of prey, such as the white-tailed eagle, are recognized to be perhaps the most vulnerable bird group regarding risk of collisions with turbines in wind-power plants. Their mortalities have called for methods capable of modelling collision risks in connection with the planning of new wind-power developments. The so-called 'Band model' estimates collision risk based on the number of birds flying through the rotor swept zone and the probability of being hit by the passing rotor blades. In the calculations for the expected collision mortality a correction factor for avoidance behaviour is included. The overarching objective of this study was to use satellite telemetry data and recorded mortality to back-calculate the correction factor for white-tailed eagles. The Smoela wind-power plant consists of 68 turbines, over an area of approximately 18 km2. Since autumn 2006 the number of collisions has been recorded on a weekly basis. The analyses were based on satellite telemetry data from 28 white-tailed eagles equipped with backpack transmitters since 2005. The correction factor (i.e. 'avoidance rate') including uncertainty levels used within the Band collision risk model for white-tailed eagles was 99% (94-100%) for spring and 100% for the other seasons. The year-round estimate, irrespective of season, was 98% (95-99%). Although the year-round estimate was similar, the correction factor for spring was higher than the correction factor of 95% derived earlier from vantage point data. The satellite telemetry data may provide an alternative way to provide insight into relative risk among seasons, and help identify periods or areas with increased risk either in a pre- or post construction situation. (Author)

  20. Exploring the isotopic niche: isotopic variance, physiological incorporation, and the temporal dynamics of foraging

    Directory of Open Access Journals (Sweden)

    Justin Douglas Yeakel

    2016-01-01

    Full Text Available Consumer foraging behaviors are dynamic, changing in response to prey availability, seasonality, competition, and even the consumer's physiological state. The isotopic composition of a consumer is a product of these factors as well as the isotopic `landscape' of its prey, i.e. the isotopic mixing space. Stable isotope mixing models are used to back-calculate the most likely proportional contribution of a set of prey to a consumer's diet based on their respective isotopic distributions, however they are disconnected from ecological process. Here we build a mechanistic framework that links the ecological and physiological processes of an individual consumer to the isotopic distribution that describes its diet, and ultimately to the isotopic composition of its own tissues, defined as its `isotopic niche’. By coupling these processes, we systematically investigate under what conditions the isotopic niche of a consumer changes as a function of both the geometric properties of its mixing space and foraging strategies that may be static or dynamic over time. Results of our derivations reveal general insight into the conditions impacting isotopic niche width as a function of consumer specialization on prey, as well as the consumer's ability to transition between diets over time. We show analytically that moderate specialization on isotopically unique prey can serve to maximize a consumer's isotopic niche width, while temporally dynamic diets will tend to result in peak isotopic variance during dietary transitions. We demonstrate the relevance of our theoretical findings by examining a marine system composed of nine invertebrate species commonly consumed by sea otters. In general, our analytical framework highlights the complex interplay of mixing space geometry and consumer dietary behavior in driving expansion and contraction of the isotopic niche. Because this approach is established on ecological mechanism, it is well-suited for enhancing the

  1. National monitoring of nicotine use in Czech and Slovak Republic based on wastewater analysis.

    Science.gov (United States)

    Mackuľak, Tomáš; Birošová, Lucia; Grabic, Roman; Škubák, Jaroslav; Bodík, Igor

    2015-09-01

    The aim of this study was to compare estimation of nicotine use in Slovakia (SR) and the Czech Republic (CR) based on cotinine analysis in wastewater from seven selected wastewater treatment plants (WWTPs) with conventional estimation based on tobacco product sales. Urinary bio-markers of nicotine use were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The study was performed concurrently at all the WWTPs (from 11 to 18 March 2014). Representative 24 h composite samples were analyzed with on line SPE/LC-MS/MS method. Based on the average residence time of wastewater in the sewers and the average time in the sampling device, specific correction coefficients were designed to improve estimation of nicotine consumption. Nicotine ingestion level was back-calculated and expressed as mass of pure drug consumed per day and per 1000 inhabitants for selected cities of both countries (mean, 2.2 g for Piešťany and 8.0 g for Nitra, respectively). Consequently, the cigarette consumption results were recalculated for each country separately and compared with the data of both national statistical offices (2362 cigarettes/year/person--SR and 2088 cigarettes/year/person--CR). Our results highly correspond to the data of national statistical offices (up to 99.9% in SR and to 96% in CR). The average amount of money invested in cigarette sales was estimated in the capitals of both countries. It is about 1 million EUR/day for Prague and about 0.3 million EUR/day for Bratislava. The calculation of nicotine consumption, utilizing a specific correction coefficient, is the correct way to obtain more accurate data in drug studies of this kind, thus allowing a better drug abuse assessment. PMID:25956519

  2. Sub-annual variability in historical water source use by Mediterranean riparian trees.

    Science.gov (United States)

    Sargeant, Christopher; Singer, Michael

    2016-04-01

    The seasonal availability of water within a tree's rooting zone may be an important determinant for individual tree growth and overall forest health, particularly in riparian corridors of Mediterranean climate zones that are vulnerable to water stress. Here, we present a new method that combines dendro-isotopes and isotope-modelling for determining how water source use varies over 10 consecutive growing seasons (2000-2010) for co-occurring species P. nigra and F. excelsior, along the Rhône River, south-eastern France. We conducted highly resolved cellulose δ18O analysis of micro-slices within tree rings and back-calculated the δ18O signature of source water available at the time of growth using a biochemical fractionation model. We related these patterns to inferred seasonal hydrological partitioning through comparison with δ18O of waters from the vadose and phreatic zones, precipitation, and streamflow. The shallowly rooted Fraxinus displayed greater sub-annual source water variability, as well as greater isotopic enrichment, reflecting use of precipitation-derived vadose moisture. Its earlywood component was formed mainly from winter rainfall (depleted) whilst the latewood relied on growing season precipitation (enriched). In Populus, the sub-annual source water use was relatively depleted, suggesting use of hyporheic water and regional groundwater. From 2007, both species converged in their pattern of water source uptake which was attributed to a decline in phreatic water access for Populus. These results demonstrate that the seasonal variability in source water use can be identified retrospectively, a method which may prove important for anticipating the future consequences of climatic driven changes to the hydrological cycle.

  3. Of travertine and time: otolith chemistry and microstructure detect provenance and demography of endangered humpback chub in Grand Canyon, USA.

    Directory of Open Access Journals (Sweden)

    Karin E Limburg

    Full Text Available We developed a geochemical atlas of the Colorado River in Grand Canyon and in its tributary, the Little Colorado River, and used it to identify provenance and habitat use by Federally Endangered humpback chub, Gila cypha. Carbon stable isotope ratios (δ(13C discriminate best between the two rivers, but fine scale analysis in otoliths requires rare, expensive instrumentation. We therefore correlated other tracers (SrSr, Ba, and Se in ratio to Ca to δ(13C that are easier to quantify in otoliths with other microchemical techniques. Although the Little Colorado River's water chemistry varies with major storm events, at base flow or near base flow (conditions occurring 84% of the time in our study its chemistry differs sufficiently from the mainstem to discriminate one from the other. Additionally, when fish egress from the natal Little Colorado River to the mainstem, they encounter cold water which causes the otolith daily growth increments to decrease in size markedly. Combining otolith growth increment analysis and microchemistry permitted estimation of size and age at first egress; size at first birthday was also estimated. Emigrants < 1 year old averaged 51.2 ± 4.4 (SE days and 35.5 ± 3.6 mm at egress; older fish that had recruited to the population averaged 100 ± 7.8 days old and 51.0 ± 2.2 mm at egress, suggesting that larger, older emigrants recruit better. Back-calculated size at age 1 was unimodal and large (78.2 ± 3.3 mm in Little Colorado caught fish but was bimodally distributed in Colorado mainstem caught fish (49.9 ± 3.6 and 79 ± 4.9 mm suggesting that humpback chub can also rear in the mainstem. The study demonstrates the coupled usage of the two rivers by this fish and highlights the need to consider both rivers when making management decisions for humpback chub recovery.

  4. Of travertine and time: otolith chemistry and microstructure detect provenance and demography of endangered humpback chub in Grand Canyon, USA.

    Science.gov (United States)

    Limburg, Karin E; Hayden, Todd A; Pine, William E; Yard, Michael D; Kozdon, Reinhard; Valley, John W

    2013-01-01

    We developed a geochemical atlas of the Colorado River in Grand Canyon and in its tributary, the Little Colorado River, and used it to identify provenance and habitat use by Federally Endangered humpback chub, Gila cypha. Carbon stable isotope ratios (δ(13)C) discriminate best between the two rivers, but fine scale analysis in otoliths requires rare, expensive instrumentation. We therefore correlated other tracers (SrSr, Ba, and Se in ratio to Ca) to δ(13)C that are easier to quantify in otoliths with other microchemical techniques. Although the Little Colorado River's water chemistry varies with major storm events, at base flow or near base flow (conditions occurring 84% of the time in our study) its chemistry differs sufficiently from the mainstem to discriminate one from the other. Additionally, when fish egress from the natal Little Colorado River to the mainstem, they encounter cold water which causes the otolith daily growth increments to decrease in size markedly. Combining otolith growth increment analysis and microchemistry permitted estimation of size and age at first egress; size at first birthday was also estimated. Emigrants < 1 year old averaged 51.2 ± 4.4 (SE) days and 35.5 ± 3.6 mm at egress; older fish that had recruited to the population averaged 100 ± 7.8 days old and 51.0 ± 2.2 mm at egress, suggesting that larger, older emigrants recruit better. Back-calculated size at age 1 was unimodal and large (78.2 ± 3.3 mm) in Little Colorado caught fish but was bimodally distributed in Colorado mainstem caught fish (49.9 ± 3.6 and 79 ± 4.9 mm) suggesting that humpback chub can also rear in the mainstem. The study demonstrates the coupled usage of the two rivers by this fish and highlights the need to consider both rivers when making management decisions for humpback chub recovery. PMID:24358346

  5. Characteristics and Propagation of Airgun Pulses in Shallow Water with Implications for Effects on Small Marine Mammals.

    Directory of Open Access Journals (Sweden)

    Line Hermannsen

    Full Text Available Airguns used in seismic surveys are among the most prevalent and powerful anthropogenic noise sources in marine habitats. They are designed to produce most energy below 100 Hz, but the pulses have also been reported to contain medium-to-high frequency components with the potential to affect small marine mammals, which have their best hearing sensitivity at higher frequencies. In shallow water environments, inhabited by many of such species, the impact of airgun noise may be particularly challenging to assess due to complex propagation conditions. To alleviate the current lack of knowledge on the characteristics and propagation of airgun pulses in shallow water with implications for effects on small marine mammals, we recorded pulses from a single airgun with three operating volumes (10 in3, 25 in3 and 40 in3 at six ranges (6, 120, 200, 400, 800 and 1300 m in a uniform shallow water habitat using two calibrated Reson 4014 hydrophones and four DSG-Ocean acoustic data recorders. We show that airgun pulses in this shallow habitat propagated out to 1300 meters in a way that can be approximated by a 18log(r geometric transmission loss model, but with a high pass filter effect from the shallow water depth. Source levels were back-calculated to 192 dB re µPa2s (sound exposure level and 200 dB re 1 µPa dB Leq-fast (rms over 125 ms duration, and the pulses contained substantial energy up to 10 kHz, even at the furthest recording station at 1300 meters. We conclude that the risk of causing hearing damage when using single airguns in shallow waters is small for both pinnipeds and porpoises. However, there is substantial potential for significant behavioral responses out to several km from the airgun, well beyond the commonly used shut-down zone of 500 meters.

  6. Drugs of abuse and alcohol consumption among different groups of population on the Greek Island of Lesvos through sewage-based epidemiology.

    Science.gov (United States)

    Gatidou, Georgia; Kinyua, Juliet; van Nuijs, Alexander L N; Gracia-Lor, Emma; Castiglioni, Sara; Covaci, Adrian; Stasinakis, Athanasios S

    2016-09-01

    The occurrence of 22 drugs of abuse, their metabolites, and the alcohol metabolite ethyl sulphate was investigated in raw sewage samples collected during the non-touristic season from three sewage treatment plants (STPs), which serve different sizes and types of population in the Greek island of Lesvos. Using the sewage-based epidemiology approach, the consumption of these substances was estimated. Five target analytes, cocaine (COC), benzoylecgonine (BE), 3,4-methylenedioxymethamphetamine (MDMA), 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH) and ethyl sulphate (EtS) were detected at concentrations above their limit of quantification, whereas the rest eighteen target compounds were not detected. THC-COOH was detected in most of the samples with concentrations ranging between MDMA were present only in the STP that serves Mytilene (the main city of the island), at mean concentrations of 3.9ngL(-1) for COC (95% CI: 1.7-6.1), 9.4ngL(-1) for BE (95% CI: -1.6-23) and 3.2ngL(-1) for MDMA (95% CI: 1.2-5.1). Back-calculations to an amount of used substance indicated more intense use of drugs among city population than rural and University population with average values of 9.5 and 1.2mgday(-1) per 1000 inhabitants for COC (95% CI: -1.43-20.4) and MDMA (95% CI: 0.52-1.85), respectively, and 2.8gday(-1) per 1000 inhabitants for tetrahydrocannabinol (THC) (95% CI: 2.4-3.1), the active ingredient of cannabis. Alcohol consumption was observed to be higher in the city population (5.4mL pure alcohol per day per inhabitant) than in the rural population (3.4mL pure alcohol per day per inhabitant), but the difference was not statistically significant. Consumption of THC differed significantly among the three STPs. PMID:27236142

  7. Evidence for multiple pulses of crystal-bearing magma during emplacement of the Doros layered intrusion, Namibia

    Science.gov (United States)

    Owen-Smith, T. M.; Ashwal, L. D.

    2015-12-01

    The Doros Complex is a relatively small (maximum 3.5 km × 7.5 km) shallow-level, lopolithic, layered mafic intrusion in the early Cretaceous Paraná-Etendeka Large Igneous Province. The stratigraphy broadly comprises a minor, fine-grained gabbroic sill and a sequence of primitive olivine-cumulate melagabbros, with a basal chilled margin, an intermediate plagioclase-cumulate olivine gabbro, and a sequence of mineralogically and texturally variable, intermediate, strongly foliated, plagioclase-, olivine- or magnetite-cumulate gabbros. An evolved syenitic (bostonite) phase occurs as cross-cutting dykes or as enclaves within the foliated gabbros. Major element modelling of the liquid line of descent shows that the spectrum of rock types, including the bostonite, is consistent with the fractionation of a basaltic parental magma that crystallised olivine, clinopyroxene, plagioclase, magnetite, K-feldspar and apatite. However, the stratigraphic succession does not correspond to a simple progressive differentiation trend but instead shows a series of punctuated trends, each defined by a compositional reversal or hiatus. Incompatible trace element concentrations do not increase upwards though the body of the intrusion. The major units show similar, mildly enriched rare earth element patterns, with minimal Eu anomalies. Back-calculation of the rare earth element concentrations of these cumulate rocks produces relatively evolved original liquid compositions, indicating fractionation of this liquid from a more primitive precursor. Based on combined field, petrographic, geochemical and geophysical evidence, we propose an origin for the Doros Complex by a minimum of seven closely spaced influxes of crystal-bearing magmas, each with phenocryst contents between 5% and 55%. These findings represent a departure from the traditional single-pulse liquid model for the formation of layered mafic intrusions and suggest the presence of an underlying magmatic mush column, i.e., a large

  8. Incidence and reproduction numbers of pertussis: estimates from serological and social contact data in five European countries.

    Directory of Open Access Journals (Sweden)

    Mirjam Kretzschmar

    2010-06-01

    Full Text Available BACKGROUND: Despite large-scale vaccination programmes, pertussis has remained endemic in all European countries and has been on the rise in many countries in the last decade. One of the reasons that have been discussed for the failure of vaccination to eliminate the disease is continued circulation of the pathogen Bordetella pertussis by mostly asymptomatic and mild infections in adolescents and adults. To understand the impact of asymptomatic and undiagnosed infection on the transmission dynamics of pertussis we analysed serological data from five European countries in combination with information about social contact patterns from five of those countries to estimate incidence and reproduction numbers. METHODS AND FINDINGS: We compared two different methods for estimating incidence from individual data on IgG pertussis toxin (PT titres. One method combines the cross-sectional surveys of titres with longitudinal information about the distribution of amplitude and decay rate of titres in a back-calculation approach. The second method uses age-dependent contact matrices and cross-sectional surveys of IgG PT titres to estimate a next generation matrix for pertussis transmission among age groups. The next generation approach allows for computation of basic reproduction numbers for five European countries. Our main findings are that the seroincidence of infections as estimated with the first method in all countries lies between 1% and 6% per annum with a peak in the adolescent age groups and a second lower peak in young adults. The incidence of infections as estimated by the second method lies slightly lower with ranges between 1% and 4% per annum. There is a remarkably good agreement of the results obtained with the two methods. The basic reproduction numbers are similar across countries at around 5.5. CONCLUSIONS: Vaccination with currently used vaccines cannot prevent continued circulation and reinfection with pertussis, but has shifted the bulk

  9. Emerging insights into the dynamics of submarine debris flows

    Science.gov (United States)

    Elverhøi, A.; Issler, D.; de Blasio, F. V.; Ilstad, T.; Harbitz, C. B.; Gauer, P.

    2005-08-01

    Recent experimental and theoretical work on the dynamics of submarine debris flows is summarized. Hydroplaning was first discovered in laboratory flows and later shown to likely occur in natural debris flows as well. It is a prime mechanism for explaining the extremely long runout distances observed in some natural debris flows even of over-consolidated clay materials. Moreover, the accelerations and high velocities reached by the flow head in a short time appear to fit well with the required initial conditions of observed tsunamis as obtained from back-calculations. Investigations of high-speed video recordings of laboratory debris flows were combined with measurements of total and pore pressure. The results are pointing towards yet another important role of ambient water: Water that intrudes from the water cushion underneath the hydroplaning head and through cracks in the upper surface of the debris flow may drastically soften initially stiff clayey material in the "neck" of the flow, where significant stretching occurs due to the reduced friction at the bottom of the hydroplaning head. This self-reinforcing process may lead to the head separating from the main body and becoming an "outrunner" block as clearly observed in several natural debris flows. Comparison of laboratory flows with different material composition indicates a gradual transition from hydroplaning plug flows of stiff clay-rich material, with a very low suspension rate, to the strongly agitated flow of sandy materials that develop a pronounced turbidity current. Statistical analysis of the great number of distinguishable lobes in the Storegga slide complex reveals power-law scaling behavior of the runout distance with the release mass over many orders of magnitude. Mathematical flow models based on viscoplastic material behavior (e.g. BING) successfully reproduce the observed scaling behavior only for relatively small clay-rich debris flows while granular (frictional) models fail at all scales

  10. Emerging insights into the dynamics of submarine debris flows

    Directory of Open Access Journals (Sweden)

    A. Elverhøi

    2005-01-01

    Full Text Available Recent experimental and theoretical work on the dynamics of submarine debris flows is summarized. Hydroplaning was first discovered in laboratory flows and later shown to likely occur in natural debris flows as well. It is a prime mechanism for explaining the extremely long runout distances observed in some natural debris flows even of over-consolidated clay materials. Moreover, the accelerations and high velocities reached by the flow head in a short time appear to fit well with the required initial conditions of observed tsunamis as obtained from back-calculations. Investigations of high-speed video recordings of laboratory debris flows were combined with measurements of total and pore pressure. The results are pointing towards yet another important role of ambient water: Water that intrudes from the water cushion underneath the hydroplaning head and through cracks in the upper surface of the debris flow may drastically soften initially stiff clayey material in the 'neck' of the flow, where significant stretching occurs due to the reduced friction at the bottom of the hydroplaning head. This self-reinforcing process may lead to the head separating from the main body and becoming an 'outrunner' block as clearly observed in several natural debris flows. Comparison of laboratory flows with different material composition indicates a gradual transition from hydroplaning plug flows of stiff clay-rich material, with a very low suspension rate, to the strongly agitated flow of sandy materials that develop a pronounced turbidity current. Statistical analysis of the great number of distinguishable lobes in the Storegga slide complex reveals power-law scaling behavior of the runout distance with the release mass over many orders of magnitude. Mathematical flow models based on viscoplastic material behavior (e.g. BING successfully reproduce the observed scaling behavior only for relatively small clay-rich debris flows while granular (frictional models

  11. Development and validation of a high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of irinotecan and its main metabolites in human plasma and its application in a clinical pharmacokinetic study.

    Directory of Open Access Journals (Sweden)

    Elena Marangon

    Full Text Available Irinotecan is currently used in several cancer regimens mainly in colorectal cancer (CRC. This drug has a narrow therapeutic range and treatment can lead to side effects, mainly neutropenia and diarrhea, frequently requiring discontinuing or lowering the drug dose. A wide inter-individual variability in irinotecan pharmacokinetic parameters and pharmacodynamics has been reported and associated to patients' genetic background. In particular, a polymorphism in the UGT1A1 gene (UGT1A1*28 has been linked to an impaired detoxification of SN-38 (irinotecan active metabolite to SN-38 glucuronide (SN-38G leading to increased toxicities. Therefore, therapeutic drug monitoring of irinotecan, SN-38 and SN-38G is recommended to personalize therapy. In order to quantify simultaneously irinotecan and its main metabolites in patients' plasma, we developed and validated a new, sensitive and specific HPLC-MS/MS method applicable to all irinotecan dosages used in clinic. This method required a small plasma volume, addition of camptothecin as internal standard and simple protein precipitation. Chromatographic separation was done on a Gemini C18 column (3 μM, 100 mm x 2.0 mm using 0.1% acetic acid/bidistilled water and 0.1% acetic acid/acetonitrile as mobile phases. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring. The standard curves were linear (R2 ≥0.9962 over the concentration ranges (10-10000 ng/mL for irinotecan, 1-500 ng/mL for SN-38 and SN-38G and 1-5000 ng/mL for APC and had good back-calculated accuracy and precision. The intra- and inter-day precision and accuracy, determined on three quality control levels for all the analytes, were always <12.3% and between 89.4% and 113.0%, respectively. Moreover, we evaluated this bioanalytical method by re-analysis of incurred samples as an additional measure of assay reproducibility. This method was successfully applied to a pharmacokinetic study in

  12. Vibrational-rotational spectra of GaF and global multi-isotopologue analysis

    Science.gov (United States)

    Uehara, Hiromichi; Horiai, Koui; Katsuie, Shunsuke

    2016-07-01

    In total, 521 vibrational-rotational spectral lines of the Δv = 1 transitions of 69GaF and 71GaF up to bands v = 5-4 and 4-3, respectively, were recorded in emission with a Fourier-transform spectrometer at unapodized resolution 0.010 cm-1 in range 625-660 cm-1. The response of a HgCdTe detector enforced the lower limit, 625 cm-1. To calibrate accurately the spectral lines, the absorption spectrum of CO2 was simultaneously recorded, using dual sample cells, to serve as wavenumber standards. A set of 782 spectral lines comprising all present vibrational-rotational spectra of 69GaF and 71GaF, the reported laser-diode measurements of the Δv = 1 band sequence and the reported rotational spectra was subjected to a global multi-isotopologue analysis through fitting with 11 isotopically invariant, irreducible molecular parameters in a single set. Normalized standard deviation 1.093 indicates a satisfactory fit. For the effects of the breakdown of the Born-Oppenheimer approximation on GaF, the values of non-Born-Oppenheimer parameters ΔBGa, ΔωGa and r1qGa(=r1qF) are experimentally determined for the first time. To facilitate the calculations or predictions of spectral frequencies, the values of the Dunham coefficients of 24 Yij and 81 band parameters for both 69GaF and 71GaF were back-calculated with uncertainties using the 11 evaluated molecular parameters. To date, various types of effective Be, re, ωe, and k have been reported for GaF. Because, in the present work, Dunham coefficients Yij are algebraically expressed with the genuine Be, ωe, ai (i = 1, …) and the non-Born-Oppenheimer correction parameters, the exact expressions for the physical significance of effective quantities are derivable. The various effective quantities of Be, re, ωe and k calculated with these expressions for the physical significance and the determined values of the fitted parameters of GaF agree satisfactorily with the reported values. The physical significance of the conventional

  13. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119

    Energy Technology Data Exchange (ETDEWEB)

    Ashmeg, S; Zhang, Y; O' Daniel, J; Yin, F; Ren, L [Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: To evaluate the accuracy of a 3D patient specific QA tool by analysis of the results produced from associated software in homogenous phantom and heterogonous patient CT. Methods: IMRT and VMAT plans of five test suites introduced by TG119 were created in ECLIPSE on a solid water phantom. The ten plans -of increasing complexity- were delivered to Delta4 to give a 3D measurement. The Delta4's “Anatomy” software uses the measured dose to back-calculate the energy fluence of the delivered beams, which is used for dose calculation in a patient CT using a pencilbeam algorithm. The effect of the modulated beams' complexity on the accuracy of the “Anatomy” calculation was evaluated. Both measured and Anatomy doses were compared to ECLIPSE calculation using 3% - 3mm gamma criteria.We also tested the effect of heterogeneity by analyzing the results of “Anatomy” calculation on a Brain VMAT and a 3D conformal lung cases. Results: In homogenous phantom, the gamma passing rates were found to be as low as 74.75% for a complex plan with high modulation. The mean passing rates were 91.47% ± 6.35% for “Anatomy” calculation and 99.46% ± 0.62% for Delta4 measurements.As for the heterogeneous cases, the rates were 96.54%±3.67% and 83.87%±9.42% for Brain VMAT and 3D lung respectively. This increased error in the lung case could be due to the use of the pencil beam algorithm as opposed to the AAA used by ECLIPSE.Also, gamma analysis showed high discrepancy along the beam edge in the “Anatomy” calculated results. This suggests a poor beam modeling in the penumbra region. Conclusion: The results show various sources of errors in “Anatomy” calculations. These include beam modeling in the penumbra region, complexity of a modulated beam (shown in homogenous phantom and brain cases) and dose calculation algorithms (3D conformal lung case)

  14. Analysis of an ordinary bedload transport event in a mountain torrent (Rio Vanti, Verona, Italy)

    Science.gov (United States)

    Pastorello, Roberta; D'Agostino, Vincenzo

    2016-04-01

    The correct simulation of the sediment-transport response of mountain torrents both for extreme and ordinary flood events is a fundamental step to understand the process, but also to drive proper decisions on the protection works. The objective of this research contribution is to reconstruct the 'ordinary' flood event with the associated sediment-graph of a flood that caused on the 14th of October, 2014 the formation of a little debris cone (about 200-210 m3) at the junction between the 'Rio Vanti' torrent catchment and the 'Selva di Progno' torrent (Veneto Region, Prealps, Verona, Italy). To this purpose, it is important to notice that a great part of equations developed for the computation of the bedload transport capacity, like for example that of Schoklitsch (1962) or Smart and Jaeggi (1983), are focused on extraordinary events heavily affecting the river-bed armour. These formulas do not provide reliable results if used on events, like the one under analysis, not too far from the bankfull conditions. The Rio Vanti event was characterized by a total rainfall depth of 36.2 mm and a back-calculated peak discharge of 6.12 m3/s with a return period of 1-2 years. The classical equations to assess the sediment transport capacity overestimate the total volume of the event of several orders of magnitude. By the consequence, the following experimental bedload transport equation has been applied (D'Agostino and Lenzi, 1999), which is valid for ordinary flood events (q: unit water discharge; qc: unit discharge of bedload transport initiation; qs: unit bedload rate; S: thalweg slope): -qs-˜= 0,04ṡ(q- qc) S3/2 In particular, starting from the real rainfall data, the hydrograph and the sediment-graph have been reconstructed. Then, comparing the total volume calculated via the above cited equation to the real volume estimated using DoD techniques on post-event photogrammetric survey, a very satisfactory agreement has been obtained. The result further supports the thesis

  15. Sequence stratigraphic controls on synsedimentary cementation and preservation of dinosaur tracks: Example from the lower Cretaceous, (Upper Albian) Dakota Formation, Southeastern Nebraska, U.S.A.

    Science.gov (United States)

    Phillips, P.L.; Ludvigson, Greg A.; Matthew, Joeckel R.; Gonzalez, Luis A.; Brenner, Richard L.; Witzke, B.J.

    2007-01-01

    A thin cemented sandstone bed in the Upper Albian Dakota Formation of southeastern Nebraska contains the first dinosaur tracks to be described from the state. Of equal importance to the tracks are stable-isotope (C, O) analyses of cements in the track bed, especially in the context of data derived from generally correlative strata (sandstones and sphaerosiderite-bearing paleosols) in the region. These data provide the framework for interpretations of paleoenvironmental conditions, as well as a novel approach to understanding mechanisms of terrestrial vertebrate track preservation. High minus-cement-porosity (> 47%) and low grain-to-grain contacts (???2.5) in the track bed indicate early (pre-compaction) lithification. Although phreatic cements dominate, the history of cementation within this stratigraphic interval is complex. Cathodoluminescence petrography reveals two distinct calcite zones in the track-bearing horizon and four cement zones in stratigraphically equivalent strata from a nearby section. The earliest calcite cements from both localities are likely coeval because they exhibit identical positive covariant trends (??18O values of - 9.89 to - 6.32??? and ??13C values of - 28.01 to - 19.33??? VPDB) and record mixing of brackish and meteoric groundwaters. All other calcite cements define meteoric calcite lines with ??18O values clustering around - 9.42??? and - 8.21??? VPDB from the track-bearing horizon, and - 7.74???, - 5.81???, and - 3.95??? VPDB from the neighboring section. Distinct meteoric sphaerosiderite lines from roughly correlative paleosols serve as a proxy for locally recharged groundwaters. Back-calculated paleogroundwater ??18O estimates from paleosol sphaerosiderites range from - 7.4 to - 4.2??? SMOW; whereas, meteoric calcite lines from the track horizon are generally more depleted. Differences in cement ??18O values record changes in paleogroundwater recharge areas over time. Early calcite cements indicate mixing of fresh and brackish

  16. Multi-species monitoring for fugitive gases and CO2 leakage at enhanced oil recovery operations

    Science.gov (United States)

    Risk, D. A.; Lavoie, M.; Brooks, B.; Goeckede, M.; Phillips, C. L.

    2013-12-01

    Carbon, Capture, and Storage (CCS) remains an option for reducing fossil CO2 emissions, but public acceptance continues to limit the roll-out of new projects. Monitoring is one mechanism by which operators can demonstrate credibility, competency, and environmental performance. While many previous research initiatives on surface monitoring have focused largely on soil gas sampling and geochemistries, fewer have tackled site-scale atmospheric detection techniques. This study aims to develop suitable techniques for identifying produced fluid leaks from wells and fugitive emissions from other associated infrastructure, and also to understand the variability of the target gases across land use types, and through time. During the growing season of 2013, we conducted multi-species atmospheric surveys of a 100 square kilometre Enhanced Oil Recovery site, using stationary and vehicle-mounted Cavity Ringdown Spectrometers (CRDS) targeting CH4, δ13C-CH4, CO2, and H2S. The study site offered excellent opportunity to study anthropogenic emissions, as it had well over 1000 active wells onsite, spatially distributed pipeline infrastructure, geochemical differentiation among the various possible emission sources, and also a road network that provided good access to most areas of the site. Leak detection using this method presented challenges related to the atmospheric transport modelling needed to back-calculate the source regions for observed anomalies. Transport models are generally not readily applicable at these smaller scales, so we developed an operational leak detection package. This package included the in situ and roving measurements, interpreted using simple mathematical models, maps, and remote sensing data, to narrow our survey search window and score sub-domains based on the gases present and the probability that these gases were man-made (as opposed to natural), in addition to the likely nature of the anthropogenic source as indicated by gas mixing ratios. Both

  17. Long-term assessment of settlement and growth of juvenile winter flounder ( Pseudopleuronectes americanus) in New Jersey estuaries

    Science.gov (United States)

    Sogard, Susan M.; Able, Kenneth W.; Hagan, Stacy M.

    2001-06-01

    We examined patterns of metamorphosis, settlement, and growth for young-of-the-year winter flounder over a ten year period (1990-1999) in four estuaries spanning the coast of New Jersey, USA, with the objective to determine the spatial and temporal coherence in these processes. We hypothesised that these processes could be influenced by large-scale climatic factors such as temperature and small-scale, local factors such as predator and prey abundances and differences associated with the localised population structure of winter flounder. Newly settled juveniles were collected in late May/early June each year. Increment counts on sagittal otoliths were used to determine the date of metamorphosis, and increment widths were used to estimate growth rates at two times, just after settlement and just prior to capture. A high level of consistency in spatial patterns among four individual estuaries was evident, and was largely driven by the northernmost site, Sandy Hook, which had higher fish densities and later metamorphosis than the three other sites, and faster growth rates than the two mid-coast sites (Barnegat Bay and Great Bay). In contrast to spatial patterns, consistent temporal patterns were evident only in the timing of metamorphosis, which was delayed in colder years at all sites. Weekly plankton sampling over the same ten year period at one site (Great Bay) yielded winter flounder larvae during a relatively narrow period in spring, with a later peak of abundance in colder years, in agreement with back-calculated dates of metamorphosis for settled juveniles. These patterns suggest that the timing of settlement is driven by large-scale climatic factors that influence the timing of spawning and/or larval development. Interannual variability in densities and growth rates, however, appeared to be independent at each site, indicating control by local environmental factors or genetic differences among local populations. The spatial consistency of growth rates suggests

  18. Validation of ELISA for the determination of anti-ricin immunoglobulin G concentration in mouse sera.

    Science.gov (United States)

    Lindsey, Changhong Y; Pace-Templeton, Judith G; Millard, Charles B; Wannemacher, Robert W; Hewetson, John F

    2006-03-01

    An enzyme-linked immunosorbent assay (ELISA) for the determination of anti-ricin immunoglobulin G (IgG) concentration in mouse sera was systematically validated. The results obtained throughout the validation process strongly demonstrated that the ELISA was reliable, reproducible, and suitable for its intended use. The assay had a high level of precision within and between runs, was specific for the anti-ricin IgG, and showed no interference with a number of different serum matrices. The assay exhibited excellent accuracy, linearity, and stability. The mean recovery of four test samples with different known concentrations was 100.9+/-11.3%, 102.7+/-10.8%, 99.0+/-7.2%, and 95.9+/-11.3%, respectively (n=10). The mean recovery of the observed anti-ricin IgG concentration of three quality control samples run on 73 plates to their nominal concentrations was 100.1+/-7.3%, 100.2+/-5.8%, and 103.7+/-8.1%; and the coefficient of variation (CV) was 7.3%, 5.8%, and 7.8%, respectively. The back-calculated anti-ricin IgG concentration, %CV, and relative error of seven standards from the calibration curves run in the entire validation study were analyzed (n=7 x 73). The results indicated that the four-parameter logistic (4PL) equation, y=(a-d)/(1+(x/c)b)+d, provided an accurate representation of a sigmoidal relationship between the measured response and the logarithm of observed concentration of anti-ricin IgG in mouse sera for this ELISA. The lower limit of quantification and upper limit of quantification of the calibration curve were 3.3 ng/ml and 82.8 ng/ml, respectively. The measurable range of the assay would cover all possible anti-ricin IgG concentrations in mouse sera stimulated with a ricin vaccine candidate, when the test sera are measured at a 1:800 starting dilution followed by four additional fourfold serial dilutions.

  19. Advanced Numerical Model for Irradiated Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Giorla, Alain B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-03-01

    In this report, we establish a numerical model for concrete exposed to irradiation to address these three critical points. The model accounts for creep in the cement paste and its coupling with damage, temperature and relative humidity. The shift in failure mode with the loading rate is also properly represented. The numerical model for creep has been validated and calibrated against different experiments in the literature [Wittmann, 1970, Le Roy, 1995]. Results from a simplified model are shown to showcase the ability of numerical homogenization to simulate irradiation effects in concrete. In future works, the complete model will be applied to the analysis of the irradiation experiments of Elleuch et al. [1972] and Kelly et al. [1969]. This requires a careful examination of the experimental environmental conditions as in both cases certain critical information are missing, including the relative humidity history. A sensitivity analysis will be conducted to provide lower and upper bounds of the concrete expansion under irradiation, and check if the scatter in the simulated results matches the one found in experiments. The numerical and experimental results will be compared in terms of expansion and loss of mechanical stiffness and strength. Both effects should be captured accordingly by the model to validate it. Once the model has been validated on these two experiments, it can be applied to simulate concrete from nuclear power plants. To do so, the materials used in these concrete must be as well characterized as possible. The main parameters required are the mechanical properties of each constituent in the concrete (aggregates, cement paste), namely the elastic modulus, the creep properties, the tensile and compressive strength, the thermal expansion coefficient, and the drying shrinkage. These can be either measured experimentally, estimated from the initial composition in the case of cement paste, or back-calculated from mechanical tests on concrete. If some

  20. A Multi-Stage Wear Model for Grid-to-Rod Fretting of Nuclear Fuel Rods

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2014-01-01

    The wear of fuel rod cladding against the supporting structures in the cores of pressurized water nuclear reactors (PWRs) is an important and potentially costly tribological issue. Grid-to-rod fretting (GTRF), as it is known, involves not only time-varying contact conditions, but also elevated temperatures, flowing hot water, aqueous tribo-corrosion, and the embrittling effects of neutron fluences. The multi-stage, closed-form analytical model described in this paper relies on published out-of-reactor wear and corrosion data and a set of simplifying assumptions to portray the conversion of frictional work into wear depth. The cladding material of interest is a zirconium-based alloy called Zircaloy-4, and the grid support is made of a harder and more wear-resistant material. Focus is on the wear of the cladding. The model involves an incubation stage, a surface oxide wear stage, and a base alloy wear stage. The wear coefficient, which is a measure of the efficiency of conversion of frictional work into wear damage, can change to reflect the evolving metallurgical condition of the alloy. Wear coefficients for Zircaloy-4 and for a polyphase zirconia layer were back-calculated for a range of times required to wear to a critical depth. Inputs for the model, like the friction coefficient, are taken from the tribology literature in lieu of in-reactor tribological data. Concepts of classical fretting were used as a basis, but are modified to enable the model to accommodate the complexities of the PWR environment. Factors like grid spring relaxation, pre-oxidation of the cladding, multiple oxide phases, gap formation, impact, and hydrogen embrittlement are part of the problem definition but uncertainties in their relative roles limits the ability to validate the model. Sample calculations of wear depth versus time in the cladding illustrate how GTRF wear might occur in a discontinuous fashion during months-long reactor operating cycles. A means to account for grid/rod gaps

  1. Daily otolith growth and ontogenetic geochemical signatures of age-0 anchovy (Engraulis encrasicolus in the Gulf of Cádiz (SW Spain.

    Directory of Open Access Journals (Sweden)

    I. A. CATALÁN

    2015-01-01

    Full Text Available The European anchovy fishery in the Gulf of Cádiz (ICES Division IXa South is largely influenced by age-0 individuals. Knowledge of young of the year growth dynamics is crucial for management, yet data on daily growth are lacking in the area. Linking growth patterns to the environment requires information on habitat occupancy through ontogeny of the fish that reach the fishery, as anchovy use different areas of the Gulf and the Guadalquivir Estuary through development. We describe the growth dynamics of age-0 anchovy through otolith microstructure analysis, and couple these data with data on microchemical signals in the otoliths to shed light into habitat use and growth dynamics in the area. Age-0 anchovy captured in September, 2011 in the Gulf ranged from 3 to 6 months old for similar sizes, with average growth rates varying twofold. Individual non-linear growth curves showed that maximum otolith growth was positively correlated with the date of spawning, which in turn was negatively correlated with the time to reach maximum growth. There was no correlation between growth parameters and body length or condition (Fulton K at capture. The strontium:calcium (Sr/Ca and magnesium:calcium (Mg/Ca ratios were significantly lower at the edge of the otolith (approximately the age of capture than at ages corresponding to larval and early juveniles (<60 days old, but values fell within typical estuarine-dwelling species. The barium:calcium ratio (Ba/Ca increased significantly in the edge of the otolith, which possibly resulted from residency in highly productive coastal waters or from ontogenetic effects. The variance in otolith elemental ratios was larger at otolith back-calculated ages around 50 days old, age which coincides with the presumed closer dependence of estuarine waters. Our data are a first step towards understanding the contribution of the estuarine system to the fishery of anchovy in the Gulf. The limitations of the approach and future

  2. Lake Roosevelt Fisheries Evaluation Program, Assessment of the Lake Roosevelt Walleye Population 1998 Annual Report, Part D.

    Energy Technology Data Exchange (ETDEWEB)

    McLellan, Jason G.; Moffatt, Holly J.; Scholz, Allan T.

    1999-08-01

    A walleye mark-recapture experiment was initiated on Lake Roosevelt in 1997, with the primary objective of estimating the size of the walleye population. The project was continued in 1998 with a revised sampling regime. The primary goals during 1998 were to estimate the size of the walleye population in Lake Roosevelt, estimate the size of the spawning run in the Spokane River Arm, and describe the age structure of the population for use in managing the population and developing a kokanee bioenergetics model. Secondary objectives included: determining walleye movements, back-calculating growth rates, estimating mortality rates, determining walleye condition, and estimating walleye young-of-the-year (YOY) production in the Spokane River Arm. All walleye, {ge} 150 mm TL, were marked with individually numbered Floy{reg_sign} tags, during five passes through the reservoir. The passes occurred between April 1st and September 16th, 1998. The most unbiased estimate of walleye abundance in Lake Roosevelt, 186,482 (40,113 {le} N {le} 943,213), was obtained using the Mtb model of the CAPTURE program. The most unbiased estimate of the size of the walleye spawning run in the Spokane River Arm, 27,345 (1,535 {le} N {le} 57,519), was calculated using the Jolly-Seber model. The abundance estimates appeared reasonable, but they had wide 95 % confidence intervals. Wide confidence intervals were attributed to low capture probabilities. Coefficient of variation (CV) values for both estimates indicated that they were not acceptable for general management, not to mention research. Despite the CV value, we felt that the reservoir estimate was reasonable and that it was the best possible, without a large increase in effort and money. The spawning run estimate could have been improved by a small increase in effort. Ages of walleye in Lake Roosevelt ranged from 0 to 13 years. Growth, mortality, and condition were all average when compared to other walleye producing waters. We recommended

  3. A model-based assessment of the TrOCA approach for estimating anthropogenic carbon in the ocean

    Directory of Open Access Journals (Sweden)

    A. Yool

    2010-02-01

    Full Text Available The quantification of the amount of anthropogenic carbon (Cant that the ocean has taken up from the atmosphere since pre-industrial times is a challenging task because of the need to deconvolute this signal from the natural, unperturbed concentration of dissolved inorganic carbon (DIC. Nonetheless, a range of techniques have been devised that perform this separation using the information implicit in other physical, biogeochemical, and man-made ocean tracers. One such method is the TrOCA approach, which belongs to a group of back-calculation techniques, but relative to other methods employs a simple parameterization for estimating the preformed, pre-industrial concentration, the key quantity needed to determine Cant. Here we examine the theoretical foundation of the TrOCA approach and test its accuracy by deconvoluting the known distribution of Cant from an ocean general circulation model (OGCM simulation of the industrial period (1864–2004. We reveal that the TrOCA tracer reflects the air-sea exchange of both natural and anthropogenic CO2 as well as that of O2. Consequently, the determination of the anthropogenic CO2 flux component requires an accurate determination not only of the contribution of the natural (pre-industrial CO2 flux component, but also of the O2 flux component. The TrOCA method attempts to achieve this by assuming that the concentration changes invoked by these two air-sea flux components scale with temperature and alkalinity. While observations support a strong exponential scaling of the oxygen flux component with temperature, there exists no simple relationship of the natural CO2 flux component with temperature and/or alkalinity. This raises doubts whether the sum of these two components can be adequately parameterized with a single function. The analyses of the model support this conclusion, even when Cant is

  4. Physical modelling of granular flows at multiple-scales and stress levels

    Science.gov (United States)

    Take, Andy; Bowman, Elisabeth; Bryant, Sarah

    2015-04-01

    regime) for the material due to the high slip velocity encountered in the granular flows. Further, the depth-averaged approach to providing an empirically-calibrated estimate of landslide travel distance was observed to match all configurations tested using a single set of empirically back-calculated frictional properties. The empirically derived basal interface friction was found to be lower than the static interface friction determined by conventional testing, suggesting that new methods are needed for the a priori determination of suitable rheological parameters for high-speed dry granular flows.

  5. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119

    International Nuclear Information System (INIS)

    Purpose: To evaluate the accuracy of a 3D patient specific QA tool by analysis of the results produced from associated software in homogenous phantom and heterogonous patient CT. Methods: IMRT and VMAT plans of five test suites introduced by TG119 were created in ECLIPSE on a solid water phantom. The ten plans -of increasing complexity- were delivered to Delta4 to give a 3D measurement. The Delta4's “Anatomy” software uses the measured dose to back-calculate the energy fluence of the delivered beams, which is used for dose calculation in a patient CT using a pencilbeam algorithm. The effect of the modulated beams' complexity on the accuracy of the “Anatomy” calculation was evaluated. Both measured and Anatomy doses were compared to ECLIPSE calculation using 3% - 3mm gamma criteria.We also tested the effect of heterogeneity by analyzing the results of “Anatomy” calculation on a Brain VMAT and a 3D conformal lung cases. Results: In homogenous phantom, the gamma passing rates were found to be as low as 74.75% for a complex plan with high modulation. The mean passing rates were 91.47% ± 6.35% for “Anatomy” calculation and 99.46% ± 0.62% for Delta4 measurements.As for the heterogeneous cases, the rates were 96.54%±3.67% and 83.87%±9.42% for Brain VMAT and 3D lung respectively. This increased error in the lung case could be due to the use of the pencil beam algorithm as opposed to the AAA used by ECLIPSE.Also, gamma analysis showed high discrepancy along the beam edge in the “Anatomy” calculated results. This suggests a poor beam modeling in the penumbra region. Conclusion: The results show various sources of errors in “Anatomy” calculations. These include beam modeling in the penumbra region, complexity of a modulated beam (shown in homogenous phantom and brain cases) and dose calculation algorithms (3D conformal lung case)

  6. r.avaflow, the GIS simulation model for avalanche and debris flows: new developments and challenges

    Science.gov (United States)

    Mergili, Martin; Queiroz de Oliveira, Gustavo; Fischer, Jan-Thomas; Krenn, Julia; Kulisch, Helmut; Malcherek, Andreas; Pudasaini, Shiva P.

    2016-04-01

    We present the latest developments and discuss some of the key challenges with regard to the novel and unified computational tool r.avaflow, representing an advanced, comprehensive, GIS-based open source simulation environment for two-phase geophysical mass flows such as avalanches of snow or rock, flows of debris or mud, and related process chains. r.avaflow is freely available and adoptable as a raster module of the GRASS GIS software (http://www.avaflow.org). We focus on the following issues: (1) We back-calculate a laboratory-scale debris flow experiment with r.avaflow and thereby show that different types of drag may govern the evolving flow dynamics, depending on the initial flow configuratiuon. In particular, it appears necessary to consider viscous ambient drag in order to achieve simulation results in line with experimentally measurements. (2) We employ a set of well-documented rock avalanche events to illustrate the use of a built-in functionality for parameter sensitivity analysis and optimization. To do so, we demonstrate possible strategies going beyond the deficient one-at-a-time simulation approach. They allow us to test three or more parameters at once with a limited number of model runs. Computational times are kept at an acceptable level by multi-core processing strategies and use of the Vienna Scientific Cluster. We further discuss a number of key issues with regard to (i) arbitrary mountain topography; and (ii) entrainment and deposition of material. Most tests indicate a good model performance when the affected areas predicted for a late stage of the flow simulation are compared with observed affected areas. However, we note that such a validation is not fully justified without the implementation of a physically correct model for the deposition process. Acknowledgement: The work was conducted as part of the international cooperation project "A GIS simulation model for avalanche and debris flows (avaflow)" supported by the Austrian Science Fund

  7. Otolith micro-structure analysis of rainbow trout alevins (Oncorhynchus mykiss under rearing conditions Análisis de la micro-estructura de otolitos en alevines de trucha arcoiris (Oncorhynchus mykiss en cautiverio

    Directory of Open Access Journals (Sweden)

    Guillermo Moyano

    2012-09-01

    Full Text Available Otolith microstructure (MO analysis was used to back-calculate growth patterns from hatching to the yolk-sac absorption in Rainbow trout alevins (Oncorhynchus mykiss, under experimental conditions, from winter to spring in Central-Chile. MO showed the following main features: (i occurrences of multiple primordia in the central region of otolith (MP; (ii several increments (22 ± 3 rings before a prominent hatch check surrounding MP and (iii existence of a very distinctive check associated to yolk-sac absorption. Further findings were the validation of daily periodicity of micro-increments and a significant linear relationship (P La micro-estructura de otolitos (MO fue utilizada para retro-calcular los patrones de crecimiento, desde la eclosión hasta la absorción del saco vitelino, en alevines de trucha arcoiris (Oncorhynchus mykiss, en la zona central de Chile. La MO mostró tres características principales: (i ocurrencia de múltiples primordios en la región central de los otolitos (MP, (ii formación de varios micro-incrementos antes de la eclosión (22 ± 3 micro-incrementos (iii y existencia de una marca distintiva correspondiente a la absorción del saco vitelino. Otros resultados fueron la validación de la periodicidad diaria de micro-incrementos y la existencia de una relación lineal significativa (P < 0,001; r2 = 0,91 entre la longitud máxima del otolito (LMO y la longitud total de los alevines (L T. La relación lineal L MO-L T validó el uso del método de intercepto biológico, para retro-calcular las tasas diarias de crecimiento (TDC. Las TDC mostraron una tendencia decreciente desde la eclosión hasta 6 días después de la absorción del saco vitelino (16 ± 1 días, las TDC variaron desde los 0,22 mm d-1 a los 0,34 mm d-1 (0,30 ± 0,037. La MO demostró ser una herramienta efectiva para el análisis retrospectivo de los patrones de crecimiento en alevins una vez absorbido su saco vitelino.

  8. 大型钢铁企业典型工序碳排放系数的确定方法探讨%Determination of carbon dioxide emission factors in typical processes for large iron-steel companies

    Institute of Scientific and Technical Information of China (English)

    张肖; 吴高明; 吴声浩; 向晓东

    2012-01-01

    In order to accurately establish the carbon dioxide emission factors in iron and steel company, the carbon dioxide emissions of the processes are calculated according to the carbon balance method and then the carbon dioxide emission factors are backcalculated based on the definition of the carbon emission factors. Here, three typical processes, i. e. , coking, sintering, and iron-smelting, in a large steel company are taken as an example. The results show that, in 2009, the carbon dioxide emission factors of the coking, sintering, and iron-smelting in this large steel company are 0. 518, 0. 210, and 1. 375, respectively. These emission factors have a good agreement with the default values, 0.56, 0.20, and 1.35, recommended by IPCC. It is indicated that this calculation method can be used to determine carbon dioxide emission factors in iron and steel company reasonably.%为准确合理地确定适合于钢铁行业实际的碳排放系数,通过碳平衡算法求出了各工序的碳排放量,然后按碳排放系数的定义反算出了各工序的碳排放系数.同时,通过对某大型钢铁企业焦化、烧结、炼铁3个典型工序的原料产能的实测数据调查,首先基于碳平衡方程计算出典型工序的碳排放量,然后由碳排放量计算其碳排放系数.最后以该大型钢铁企业2009年的调查数据为例,按本方法计算出的焦化、烧结、炼铁工序的碳排放系数分别为0.518、0.210、1.375,与IPCC提供的默认值(0.56、0.20、1.35)极为吻合.这一结果表明,该方法用于我国钢铁行业碳排放系数体系的建立是可行的.

  9. Apparent source levels and active communication space of whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary and Beibu Gulf, China.

    Science.gov (United States)

    Wang, Zhi-Tao; W L Au, Whitlow; Rendell, Luke; Wang, Ke-Xiong; Wu, Hai-Ping; Wu, Yu-Ping; Liu, Jian-Chang; Duan, Guo-Qin; Cao, Han-Jiang; Wang, Ding

    2016-01-01

    Background. Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats. Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR ≥10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS). Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5 ± 6.8 (mean ± standard deviation) and 137.2 ± 7.0 dB re 1 µPa in PRE (N = 33) and BG (N = 209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 ± 2.6 (median ± quartile deviation) and 17.1± 3.5 m in PRE, and 34.2 ± 9.5 and 43.5 ± 12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 ± 4.8 and 35.7 ± 4.6 m for PRE, and 60.7 ± 18.1 and 74.3 ± 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types. Discussion. Besides shedding some light for evaluating appropriate noise exposure

  10. 徽水河宽鳍的年龄、生长和繁殖%AGE,GROWTH AND REPRODUCTION OF ZACCO PLATYPUS IN THE HUISHUI STREAM

    Institute of Scientific and Technical Information of China (English)

    严云志; 闫莉莉; 储玲; 梁阳阳; 陈毅峰; 章星明

    2012-01-01

    Identifying the life history of fishes is the basis for scientifically protecting fish species diversity and reasonably managing fishery resources. In this study, age, growth and reproduction of Zacco platypus in the Huishui Stream were examined using 352 specimens collected monthly from May 2009 to April 2010. Sex ratio was 0.49 : 1 (female: male), which was significantly different from 1 : 1 by X2 test. Using scales for age determination, the largest longevities were both age 3 for females and males. Based on the monthly changes in marginal increment ratio (MIR), annuli on scales were formed during March, which was associated with the relatively low water temperature constraining the somatic growth in winter. The relationships between total length (L) and weight (W) were W = 5×10 L for females and W = 7×10 L for males. Due to no significant difference discovered by ANCOVA between sexes, L-W relationship was combined as W = 6×10-6L3.10 for both sexes. L-R (scale radius) equations were L = 29.58R + 38.84 for females and L = 33.17R + 34.99 for males, and significant difference was observed between them. The back-calculated total lengths (BCL) at age 2 were (82.59 ± 9.77) mm for females and (84.65 ± 11.77) mm for males, and those age 3 were 120.56 mm (only one specimen) for females and (94.97± 9.85) mm for males. According to /-test result, no significant difference was observed in BCL at age 2 between the two sexes. The monthly changes in gonado-somatic index (GSI) suggested that Z. platypus spawned from April through July, which was almost synchronous with local flooding period, because flood could bring sufficient food for larva and decrease the risk that larva were preyed by predators. Fifty percentage of individuals got the first maturity at age 2, when the average total lengths were 98.22 mm for females and 105.69 mm for males. In terms of the number of the occytes with vitellinogenic granules from mature ovaries, the absolute fecundity (AF) and relative

  11. Evaluation of cyclic shear stress-strain using inverse analysis techniques in dynamic centrifuge tests%动力离心模型试验循环剪应力-剪应变反演方法对比

    Institute of Scientific and Technical Information of China (English)

    王永志; Daniel W Wilson; Mohammad Khosravi; 袁晓铭; C Guney Olgum

    2016-01-01

    介绍了基于加速度阵列建立的3种循环剪应力–剪应变反演方法,分析了应用条件和影响因素。基于一组软黏土场地加固动力离心模型试验,探讨了试验加速度记录反演位移的信号处理方法,与多状态下实测位移对比,验证了有效性与可靠性。运用3种反演方法分别求取了两次试验、多种波激励下,自由场地和加固场地内土体剪应力–剪应变动态响应过程。结果表明,在传感器布设间距和采样率满足应用条件下,3种反演方法可获得基本一致结果并反映基本规律,上层土体剪应力小、剪应变大,土体剪切模量与围压密切联系;自由场地剪应变远大于加固场地,并因土体软化呈现强非线性。3种方法对比,三次样条法反演结果准确性对传感器布设间距和采样率较为敏感。%Evaluation of shear stress-strain characteristics in soils is paramount to the fundamental understanding of soil behavior in dynamic centrifuge tests. Three inverse analysis techniques for evaluating cyclic shear stress-strain response using data from accelerometer arrays are introduced and key factors that require consideration in the applied condition are discussed. Using a series of dynamic centrifuge tests on soft soil sites with stiff ground reinforcement, the data process for back-calculated displacements from acceleration records is presented. The back calculated displacements are compared to the recorded displacements in several cases with excellent agreements. The three inverse analysis techniques are used to estimate the dynamic shear stress-strain responses in the free field and with in the reinforced ground in two centrifuge tests with different shaking motions of varying magnitudes. The results demonstrate that as long as accelerometer spacing and sampling frequency are sufficient to the active mechanics, the calculated shear stress-strain responses from three inverse techniques are

  12. Quantifying moisture transport in cementitious materials using neutron radiography

    Science.gov (United States)

    Lucero, Catherine L.

    A portion of the concrete pavements in the US have recently been observed to have premature joint deterioration. This damage is caused in part by the ingress of fluids, like water, salt water, or deicing salts. The ingress of these fluids can damage concrete when they freeze and expand or can react with the cementitious matrix causing damage. To determine the quality of concrete for assessing potential service life it is often necessary to measure the rate of fluid ingress, or sorptivity. Neutron imaging is a powerful method for quantifying fluid penetration since it can describe where water has penetrated, how quickly it has penetrated and the volume of water in the concrete or mortar. Neutrons are sensitive to light atoms such as hydrogen and thus clearly detect water at high spatial and temporal resolution. It can be used to detect small changes in moisture content and is ideal for monitoring wetting and drying in mortar exposed to various fluids. This study aimed at developing a method to accurately estimate moisture content in mortar. The common practice is to image the material dry as a reference before exposing to fluid and normalizing subsequent images to the reference. The volume of water can then be computed using the Beer-Lambert law. This method can be limiting because it requires exact image alignment between the reference image and all subsequent images. A model of neutron attenuation in a multi-phase cementitious composite was developed to be used in cases where a reference image is not available. The attenuation coefficients for water, un-hydrated cement, and sand were directly calculated from the neutron images. The attenuation coefficient for the hydration products was then back-calculated. The model can estimate the degree of saturation in a mortar with known mixture proportions without using a reference image for calculation. Absorption in mortars exposed to various fluids (i.e., deionized water and calcium chloride solutions) were investigated

  13. TRUE Block Scale Continuation Project. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Peter; Byegaard, Johan [Geosigma AB (Sweden); Billaux, Daniel [Itasca Consultants SA (France); Cvetkovic, Vladimir [Royal Inst. of Technology, Stockholm (Sweden); Dershowitz, William; Doe, Thomas [Golder Associates Inc. (United States); Hermanson, Jan [Golder Associates AB (Sweden); Poteri, Antti [VTT (Finland); Tullborg, Eva-Lena [Terralogica AB (Sweden); Winberg, Anders [Conterra AB (SE)] (ed.)

    2007-03-15

    The TRUE Block Scale project was carried out during 1996-2002. This project focused on site characterisation and building of hydrostructural and microstructural models, sorbing tracer experiments in single structures and networks of structures over distances ranging between 1 and 100 m and also involved a unified application of various model approaches for modelling the in situ experiments. In 2002, ANDRA, Posiva, JNC and SKB decided to pursue some remaining issues in the so-called TRUE Block Scale Continuation project (TRUE BS2). The specific objectives of BS2 can be summarised as: 'Improve understanding of transport pathways at the block scale, including assessment of effects of geology and geometry, macrostructure and microstructure'. In order to cater to addressing the stated objective a series of hypotheses were formulated which explored the importance of geological information for predicting transport and retention and the possible differences between transport and retention between transport paths dominated by faults and those dominated by non-fault fractures (background fractures). In the process, prospects for carrying out experiments in fracture networks over longer distances (c 20-100 m) were explored. It was identified that experiments with sorbing tracers over these distances were prohibitive because of the time frames involved and the projected low mass recoveries. Instead the experimental locus was shifted to a geological structure previously not investigated by tracer tests in the TRUE Block Scale experiments. The lower immobile zone retention material properties assigned to background fractures compared to those assigned to the fault-type Structure 19 have been verified by means of back-calculations. The evaluated Type 1 flow path (Structure 19, Flow path I) retention material properties, as expressed by {kappa} parameter, are one order of magnitude higher than for the background fracture flow path. This finding is consistent with the

  14. An integrated multi-scale risk analysis procedure for pluvial flooding

    Science.gov (United States)

    Tader, Andreas; Mergili, Martin; Jäger, Stefan; Glade, Thomas; Neuhold, Clemens; Stiefelmeyer, Heinz

    2016-04-01

    its vulnerability. (iii) The object-based hazards, exposures, vulnerabilities and risks can be scaled to any spatial unit desired. For this purpose we have developed an automated work flow building on the Python programming language in combination with ArcGIS and the R statistical software. This enables us to easily adapt the resulting risk indication maps to different zooming levels; to build statistics for various types of units; to flexibly react to the needs of the end users; and to account for the availability of reference data for validation. In the present study, we scale the results to the level of postal code zones. The evaluation of the results is based on loss reports of an insurance company and on photographs and videos obtained from various sources. We show a potential of the suggested work flow to reproduce the documented damages at the level of postal code zones. However, the results are very sensitive to the input parameters and model assumptions, and a robust back-calculation even of well-documented events remains a major challenge. Ultimately, we aim at integrating the procedure presented in a work flow for generating risk indication maps for pluvial flooding throughout the entire territory of Austria.

  15. Trace-Element Partitioning Between Low- and High-Ca Pyroxenes in Cumulate Eucrite Binda

    Science.gov (United States)

    Pun, A.; Papike, J. J.; Layne, G. D.

    1993-07-01

    +. Figure 1 clearly demonstrates that augite is an important repository for REE in solid-solid partitioning at subsolidus conditions. Subsolidus reequilibration temperatures were calculated for the lamellae-host pairs using two-pyroxene geothermometry [4]. Temperatures ranging from 900 degrees C to 850 degrees C were calculated for grain 1, whereas temperatures from 850 degrees C to 700 degrees C were determined for grain 2. Calculated temperatures are consistent with equilibrium pigeonite/augite subsolidus phase relations [5]. Differences in calculated temperatures and abundances of the REE between the two measured grains may be a function of their crystallization history, reflecting different temperatures of equilibration and/or slight differences in melt compositions. Our study demonstrates the importance of considering the partitioning of trace elements during pyroxene exsolution. These results indicate that it would be extremely difficult to use the trace-element concentrations in inverted pigeonites to back-calculate parental melt compositions. Acknowledgments: We thank M. N. Spilde for technical assistance and the Smithsonian Institution for the thin section of Binda. This work was supported by NASA grant NAGW-3347 (J.J. Papike) and NGT-70223 (NASA GSRP training grant for A. Pun). References: [1] Anders E. and Grevesse N. (1989) GCA, 53, 197-214. [2] Papike J. J. et al. (1988) LPS XIX, 901-902. [3] Shearer C. K. et al. (1989) GCA, 53, 1041-1054. [4] Lindsley D. H. (1983) Am. Mineral., 68, 477-493. [5] Papike J. J. and Cameron M. (1976) Rev. Geophy. Space Phys., 14, 37- 80. Fig. 1 appears here in the hard copy.

  16. Combined statistical analysis of landslide release and propagation

    Science.gov (United States)

    Mergili, Martin; Rohmaneo, Mohammad; Chu, Hone-Jay

    2016-04-01

    Statistical methods - often coupled with stochastic concepts - are commonly employed to relate areas affected by landslides with environmental layers, and to estimate spatial landslide probabilities by applying these relationships. However, such methods only concern the release of landslides, disregarding their motion. Conceptual models for mass flow routing are used for estimating landslide travel distances and possible impact areas. Automated approaches combining release and impact probabilities are rare. The present work attempts to fill this gap by a fully automated procedure combining statistical and stochastic elements, building on the open source GRASS GIS software: (1) The landslide inventory is subset into release and deposition zones. (2) We employ a traditional statistical approach to estimate the spatial release probability of landslides. (3) We back-calculate the probability distribution of the angle of reach of the observed landslides, employing the software tool r.randomwalk. One set of random walks is routed downslope from each pixel defined as release area. Each random walk stops when leaving the observed impact area of the landslide. (4) The cumulative probability function (cdf) derived in (3) is used as input to route a set of random walks downslope from each pixel in the study area through the DEM, assigning the probability gained from the cdf to each pixel along the path (impact probability). The impact probability of a pixel is defined as the average impact probability of all sets of random walks impacting a pixel. Further, the average release probabilities of the release pixels of all sets of random walks impacting a given pixel are stored along with the area of the possible release zone. (5) We compute the zonal release probability by increasing the release probability according to the size of the release zone - the larger the zone, the larger the probability that a landslide will originate from at least one pixel within this zone. We

  17. 印度北方河流中主要鲤科鱼类卡拉(鱾)的年龄和生长%Age and growth profile of Indian major carps Catla catla from rivers of Northern India

    Institute of Scientific and Technical Information of China (English)

    Prashant K. DEEPAK; Uttam K. SARKAR; Raje S. NEGI; Samir K PAUL

    2008-01-01

    为了获得印度北部赣达(Ganga)盆地河流中野生卡特拉(鱾)种群的年龄结构和重要生长参数,对该鱼的年龄和生长进行了研究.鳞片取自商业捕捞和实验室饲养的样品.根据研究分析,该鱼最大年龄可达8龄;巴吉拉蒂河(Bhagirathi R.)的种群平均体长为521.51 mm,退算体长为288.9-1132.3 mm;旁遮普邦(Punjab)Satluj河种群平均体长为641.6 mm,退算体长为335.4-1096.08 mm.2龄时,种群线性生长率(Cl)和体重增加率(Cw)表现出迅速下降的趋势.其它生长参数值(Clt)也呈现快速下降.退算体长差异(ANOVA)分析显示,生活在赣达盆地不同流域中的种群,1+-4+龄组的长度差异较明显(P<0.05),高龄组(5+-8+)差异不显著.根据本项研究结果,提出了对印度北部赣达盆地相关河流中生活的野生卡特拉(鱾)种群资源持续利用的对策.%In the present communication age and growth of Catla catla (Hamilton-Buchanan 1822) was studied in order to obtain the information on its age structure and important growth parameters in the wild populations of rivers of the Ganga basin in the Northern India. Scales were collected from commercial and experimental catch. Based on the analysis we found C.catla with a maximum age group 8+ from river Bhagirathi where mean total length (TL) was 521.51 mm and the back calculated length were ranged from 288.9 to 1132.3 mm and from river Satluj, Punjab with a mean total length of 641.6 mm and back calculated length data were ranged from 335.4 to 1096.08 mm. The specific rate of linear growth (Cl) and specific rate of weight increase (Cw) of the entire population exhibited sharp decreasing trend in 2+ age group. The value of other growth parameter (Clt) showed an abrupt decreasing trend. Analyses of variances (ANOVA) of the back-calculated length data showed significant variation (P<0.05) in length attainment between the different drainages of river Ganga basin for the age groups up to 1+ to 4+ only, however, no

  18. Uncertainties in risk assessment and decision making

    International Nuclear Information System (INIS)

    The general concept for risk assessment in accordance with the Swedish model for contaminated soil implies that the toxicological reference value for a given receptor is first back-calculated to a corresponding concentration of a compound in soil and (if applicable) then modified with respect to e.g. background levels, acute toxicity, and factor of safety. This result in a guideline value that is subsequently compared to the observed concentration levels. Many sources of uncertainty exist when assessing whether the risk for a receptor is significant or not. In this study, the uncertainty aspects have been addressed from three standpoints: 1. Uncertainty in the comparison between the level of contamination (source) and a given risk criterion (e.g. a guideline value) and possible implications on subsequent decisions. This type of uncertainty is considered to be most important in situations where a contaminant is expected to be spatially heterogeneous without any tendency to form isolated clusters (hotspots) that can be easily delineated, i.e. where mean values are appropriate to compare to the risk criterion. 2. Uncertainty in spatial distribution of a contaminant. Spatial uncertainty should be accounted for when hotspots are to be delineated and the volume of soil contaminated with levels above a stated decision criterion has to be assessed (quantified). 3. Uncertainty in an ecological exposure model with regard to the moving pattern of a receptor in relation to spatial distribution of contaminant in question. The study points out that the choice of methodology to characterize the relation between contaminant concentration and a pre-defined risk criterion is governed by a conceptual perception of the contaminant's spatial distribution and also depends on the structure of collected data (observations). How uncertainty in transition from contaminant concentration into risk criterion can be quantified was demonstrated by applying hypothesis tests and the concept of

  19. Development of Alternate Soil Clean-Up Goals for Hanford Waste Sites Using Fate and Transport Modeling

    International Nuclear Information System (INIS)

    Remedial Action Goals (RAGs) for soil contaminant levels that are protective of groundwater have been determined for the Removal/Treatment/Disposal (RTD) sites at the 200-UW-1 Operable Unit on the Hanford Site. The RAG values were determined using a methodology involving the back-calculation of soil contaminant levels protective of groundwater (i.e., resulting groundwater concentrations are ≤ MCLs) in conjunction with the fate and transport modeling as a risk-based alternative to the currently prescribed use of background or detection limit default values. This methodology is important for waste management activities at the Hanford Site because it provides risk-based metrics and a technical basis for determining the levels of contamination 'left in place' in the Hanford Site vadose zone that are protective of human health and the environment. The methodology and the use of fate and transport modeling described here comply with federal guidelines for the use of environmental models. This approach is also consistent with one of several allowable methods identified in State guidelines for deriving soil concentrations for ground water protection. Federal and state guidelines recommend the use of site-specific information and data in risk-based assessments of risk and/or protectiveness. The site-specific characteristics of the Hanford Site, which include consideration of the semi-arid climate, an unsaturated zone thickness of over 80 m (262 feet), and associated/other site features and processes, are integral for the risk-based assessments associated with the protection of groundwater pathway. This methodology yields soil cleanup values (RAGs) for the 200-UW-1 OU waste sites selected for the removal/treatment/disposal (RTD) remedy. These proposed RAGs for uranium, nitrate, and technetium-99 are derived from soil concentrations calculated not to cause contamination of groundwater at levels that exceed the ground water MCLs, and are 40 to 200 times greater than

  20. Probabilistic risk assessment for linear alkylbenzene sulfonate (LAS) in sewage sludge used on agricultural soil.

    Science.gov (United States)

    Schowanek, Diederik; David, Helen; Francaviglia, Rosa; Hall, Jeremy; Kirchmann, Holger; Krogh, Paul Henning; Schraepen, Nathalie; Smith, Stephen; Wildemann, Tanja

    2007-12-01

    Deterministic and probabilistic risk assessments were developed for commercial LAS in agricultural soil amended with sewage sludge. The procedure done according to ILSI Europe's Conceptual Framework [Schowanek, D., Carr, R., David, H., Douben, P., Hall, J., Kirchmann, H., Patria, L., Sequi, P., Smith, S., Webb, S.F., 2004. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture-conceptual Framework. Regul. Toxicol. Pharmacol. 40 (3), 227-251], consists of three main steps. First, the most sensitive endpoint was determined. This was found to be the chronic ecotoxicity of LAS to soil invertebrates and plants. Additional endpoints, such as potential for plant uptake and transfer in the food chain, leaching to groundwater, surface erosion run-off, human health risk via drinking water, plant consumption and soil ingestion were also systematically evaluated but were all assessed to be of little toxicological significance. In the second step, a back-calculation was conducted from the Predicted No-Effect Concentration in soil (PNECsoil) to a safe level of LAS in sludge (here called 'Sludge Quality Standard'; SQS). The deterministic approach followed the default agricultural soil exposure scenario in the EU-Technical Guidance Document (TGD). The SQS for LAS was calculated as 49 g/kg sludge Dry Matter (DM). In order to assess the potential variability as a result of varying agricultural practices and local environmental conditions, two probabilistic exposure assessment scenarios were also developed. The mean SQS was estimated at 55 and 27.5 g/kg DM for the homogeneous soil mixing and soil injection scenarios, respectively. In the final step, the resulting SQS values were evaluated for consistency and relevance versus available information from agricultural experience and field tests. No build-up, adverse impact on soil fertility, agronomic performance, or animal/human health have been reported for agricultural

  1. Effects of surface applications of biosolids on soil, crops, ground water, and streambed sediment near Deer Trail, Colorado, 1999-2003

    Science.gov (United States)

    Yager, Tracy J.B.; Smith, David B.; Crock, James G.

    2004-01-01

    The U.S. Geological Survey, in cooperation with Metro Wastewater Reclamation District and North Kiowa Bijou Groundwater Management District, studied natural geochemical effects and the effects of biosolids applications to the Metro Wastewater Reclamation District properties near Deer Trail, Colorado, during 1999 through 2003 because of public concern about potential contamination of soil, crops, ground water, and surface water from biosolids applications. Parameters analyzed for each monitoring component included arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc (the nine trace elements regulated by Colorado for biosolids), gross alpha and gross beta radioactivity, and plutonium, as well as other parameters. Concentrations of the nine regulated trace elements in biosolids were relatively uniform and did not exceed applicable regulatory standards. All plutonium concentrations in biosolids were below the minimum detectable level and were near zero. The most soluble elements in biosolids were arsenic, molybdenum, nickel, phosphorus, and selenium. Elevated concentrations of bismuth, mercury, phosphorus, and silver would be the most likely inorganic biosolids signature to indicate that soil or streambed sediment has been affected by biosolids. Molybdenum and tungsten, and to a lesser degree antimony, cadmium, cobalt, copper, mercury, nickel, phosphorus, and selenium, would be the most likely inorganic 'biosolids signature' to indicate ground water or surface water has been affected by biosolids. Soil data indicate that biosolids have had no measurable effect on the concentration of the constituents monitored. Arsenic concentrations in soil of both Arapahoe and Elbert County monitoring sites (like soil from all parts of Colorado) exceed the Colorado soil remediation objectives and soil cleanup standards, which were determined by back-calculating a soil concentration equivalent to a one-in-a-million cumulative cancer risk. Lead concentrations

  2. Occurrence and environmental implications of the presence of drugs of abuse in wastewater treatment plants of Valencia (Spain)

    Science.gov (United States)

    Picó, Yolanda; Andres-Costa, M. Jesus; Andreu, Vicente

    2014-05-01

    Drugs of abuse are continuously discharged into wastewaters due to human excretion as parent compounds and/or secondary metabolites after consumption or accidental disposal into the toilets. (Boles and Wells,2010). Incomplete removal of these compounds during wastewater treatment results in their release to the environment. Pollution by illicit drug residues at very low concentrations is generalized in populated areas, with potential risks for human health and the environment. The impact of treated wastewater effluent on the quality of receiving waters can be evaluated performing an investigated performing an ecotoxicological risk assessment calculating the risk quotient (RQ) of the drugs of abuse level observed. In addition, back-calculation from the concentration of illicit drug in the influents of wastewater treatment plants (WWTPs) provides an important tool for estimating its local consumption (Daughton 2001). Sampling campaigns were in three years, 2011 (March 9th to 15th), 2012 (April 17th to May 1st) and 2013 (March 6th to 12th) in influents and effluents from 3 Wastewater Treatment Plants (WWTPs), Pinedo I, Pinedo II and Quart-Benàger, that treats most of the wastewater of Valencia City and its surrounding towns. Cocaine (COC), amphetamine (AMP), methamphetamine (MAMP), ecstasy (MDMA) and ketamine (KET), Benzoylecgonine (BE), 6-acethylmorphine (6-MAM), and 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THC-COOH) were analyzed using mass spectrometry techniques such as liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS/MS) Illicit drugs were extracted using solid phase extraction (SPE) and determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive ionization with an electrospray ionization source (ESI). The determination of drugs of abuse in the influent of the selected WWTP shows that all compounds were detected in 100% of influents from Pinedo I, Pinedo II and Quart-Benàger in samples analyzed during three years

  3. Age and growth of the Argentine hake Merluccius hubbsi Marini, 1933 in the Brazilian South-Southeast Region during 1996-2001

    Directory of Open Access Journals (Sweden)

    André M. Vaz-dos-Santos

    2007-09-01

    Full Text Available This is the first detailed study on the age and growth of the Argentine hake Merluccius hubbsi in Brazilian waters. A total of 3,651 specimens obtained from surveys and sampling landings using trawlers and long-lines in the South-Southeast Region (21ºS to 34ºS between 1996 and 2001 were analyzed. Readings of sliced and burned otoliths were conducted on 686 individuals (397 females, 129 males and 160 young - sex not identified, identifying opaque and translucent zones. Marginal increment and edge type percentage methods were used for validation, resulting in one ring per year, formed during summer-autumn. Fish with no more than eight rings and six years of age were found, the two first rings after the core being formed during the first year. Back-calculation methods were applied to length/age data and the parameters of von Bertalanffy's growth model were fitted based on average length per ring. The value of maximum theoretical length varied between 470.27 mm and 807.40 mm; growth coefficient varied from 0.1657 to 0.3555 year-1 and the theoretical age at length zero between -1.2846 and -0.4552 years. Growth of females and males differed significantly. The techniques applied and the results obtained are discussed and compared with studies on hake conducted in Uruguay and Argentina, providing important information for the management of the species in Brazil, where it presents clear signs of overexploitation.Este é o primeiro estudo detalhado sobre a idade e o crescimento da merluza Merluccius hubbsi no Brasil. Foram analisados 3.651 espécimes obtidos em cruzeiros de pesquisa e provenientes das frotas de arrasto e espinhel de fundo da região Sudeste-Sul do Brasil (21ºS a 34ºS entre 1996 e 2001. Leituras de secções transversais de otólitos (corte, polimento e queima foram realizadas para 686 indivíduos (397 fêmeas, 129 machos e 160 jovens com sexo não identificado, identificando-se zonas opacas e translúcidas. Foram calculados o

  4. Analysis and reconstructed modelling of the debris flow event of the 21st of July 2012 of St. Lorenzen (Styria, Austira)

    Science.gov (United States)

    Janu, Stefan; Mehlhorn, Susanne; Moser, Markus

    2013-04-01

    Analysis and reconstructed modelling of the debris flow event of the 21st of July 2012 of St. Lorenzen (Styria, Austria) Authors: Stefan Janu, Susanne Mehlhorn, Markus Moser The village of St. Lorenzen, in the Styrian Palten valley is situated on the banks of the Lorenz torrent, in which a debris flow event occurred in the early morning hours of the 21st of July 2012, causing catastrophic damage to residential buildings and other infrastructural facilities. In the ministry-approved hazard zone map of 2009, the flood water discharge and bedload volume associated with a 150-year event was estimated at 34 m³/s and 25,000 m³ respectively for the 5.84 km² catchment area. The bedload transport capacity of the torrent was classified as ranging from 'heavy' to 'capable of producing debris flows'. The dominant process type of the mass movement event may be described as a fine-grained debris flow. The damage in the residential area of St.Lorenzen was caused by a debris flow pulse in the lower reach of the Lorenz torrent. This debris flow pulse was in turn caused by numerous landslides along the middle reaches of the torrent, some of which caused blockages, ultimately leading to an outburst event in the main torrent. Discharge cross-sections ranging from 65 - 90 m², and over 100 m² in a few instances, were measured upstream of the St. Lorenzen residential area. Back-calculations of velocities yielded an average debris flow velocity along the middle reaches of the torrent between 11 and 16 m/s. An average velocity of 9 m/s was calculated for the debris flow at the neck of the alluvial fan directly behind the center of the village. Due to both the high discharge values as well as to the height of the mass movement deposits, the natural hazard event of 21 July 2012 in St. Lorenzen is clearly to be described as having had an extreme intensity. A total of 67 buildings were damaged along the Lorenz torrent, 7 of were completely destroyed. According to the Austrian Service for

  5. 湘江鳡仔稚鱼个体和耳石生长发育研究%SOMATIC AND LAPILLUS OTOLITH ONTOGENETIC GROWTH AND DEVELOPMENT IN LARVAL AND JUVENILE ELOPICHTHYS BAMBUSA RICHARDSON IN THE XIANG RIVER

    Institute of Scientific and Technical Information of China (English)

    向建国; 向劲; 王星璐; 李钟杰; 谢松光

    2011-01-01

    E. Bambusa was collected in the Xiang River from June to July, 2008. Otolith analysis revealed that age of the specimens ranged from 4-25 days, and the back-calculated hatching dates were during May 27th to June 22nd. The mid-age of stage transition from preflexion to flexion was at the 6th day; from flexion to postflexion was at the 10th day; from postflexion to juvenile was at the 15.5th day. Piecewise regression revealed a knot in the growth functions of either body length or otolith radius, were both at the early postflexion stage (the 12nd-13rd day): the growth rate after the knot was 5 times and twice of that before the knot for body length and otolith radius respectively. The shape of lapillus was round in the preflexion stage; in the flexion stage, the anterior-posterior axis growth significantly exceeded along the dorsal-ventral axis, and the shape became oval; the otolith further elongated in the postflexion stage, and the peak of the posterior emerged to shape the whole lapillus pear; in the juvenile stage, the peak smoothed and the shape was mussel. Otolith shape and microstructural analyses can provide essential information revealing the critical events in the early life history of £. Bambusa.

  6. GROWTH AND REPRODUCTIVE CHARACTERISTICS OF ANCHERYTHROCULTER KUREMATSUI KIMURA%高体近红鲌的生长与繁殖

    Institute of Scientific and Technical Information of China (English)

    刘飞; 吴金明; 王剑伟

    2011-01-01

    Ancherythroculter kurematsui Kimura is an endemic fish of the Yangtze River, and lives only in the upper reaches of the Yangtze River basin, mainly in Sichuan Province and Chongqing City, China. As an endemic genus, the Ancherythroculter Yih et Woo is thought to be important in fish taxonomy and zoogeography studying. Growth is an important aspect of the ecology and life history of fish, and quantification of growth is frequently a crucial part of fisheries research and management. Unfortunately, few studies have been conducted to describe the growth and reproductive characteristics of A. Kurematsui. The purpose of this study was therefore to determine age structure and growth characteristics of A. Kurematsui. A total of 540 specimens of A. Kurematsui were collected during May to November 2008 from the Chishui River, a first-order tributary of Yangtze River. The population age structure and growth characteristics of A. Kurematsui were studied. The results showed that the population of A. Kurematsui had a relatively simple age structure which only contains 4 age classes. The age structure of A. Kurematsui was dominated by young individuals, and over 95% of the total were age 2 and age 3. Body length range of the population was 81-182 mm, mainly between 100 mm and 160 mm (88.21%), and body weight ranged from 8.7 g to 84.7 g, mainly between 20.0 g and 50.0 g (69.93%). The total sex ratio (♀:♂) of the population was 1.30 : 1, which showed there were much more female individuals than male. The fish scale is a kind of appropriate material for age determination; the new annual rings on scales formed mainly in August and September, and all new annual rings were formed before November. The radii of scale (from focus to the flank) took on linear relationship with body length, which could be used for body length back-calculation. The relationship between body length and radii of scale was described as L=0.0169R+0.0815 (r=0.9305, n=487). There was little evidence of