WorldWideScience

Sample records for backcalculation

  1. Will Nonlinear Backcalculation Help?

    DEFF Research Database (Denmark)

    Ullidtz, Per

    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. For...

  2. Will Nonlinear Backcalculation Help?

    DEFF Research Database (Denmark)

    Ullidtz, Per

    2000-01-01

    Backcalculation of FWD data often results in unrealistic moduli. The modulus of the subgrade may be two to three times the expected value, and the modulus of an intermediate granular material may be lower than the subgrade modulus. If stresses or strains measured in the pavement are compared with...... theoretical values, the agreement is often poor.All theoretical models for calculating pavement response are based on a number of simplifications with respect to reality and must be verified experimentally. Most models assume that all pavement layers consist of linear elastic materials. This paper...

  3. 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%.

  4. Analytical Approaches for Addressing The Variation in Back-Calculated Age-Length Relationships for Fish

    OpenAIRE

    Shephard, Samuel; Jackson, Donald C.

    2009-01-01

    Estimating an age-length relationship is a routine aspect of many fisheries studies and is simplified by the use of commercially available computer programs. These computer programs may be misleading since a result can be produced irrespective of the quality or the extent of the data, and there is some concern that back-calculated age-length relationships are sensitive to the sample size and composition. We investigated this issue by comparing estimates of mean back-calculated lengths at age ...

  5. 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. PMID:23808694

  6. Analytical approaches for addressing the variation in back-calculated age-length relationships for fish.

    Science.gov (United States)

    Shephard, Samuel; Jackson, Donald C

    2009-12-01

    Estimating an age-length relationship is a routine aspect of many fisheries studies and is simplified by the use of commercially available computer programs. These computer programs may be misleading since a result can be produced irrespective of the quality or the extent of the data, and there is some concern that back-calculated age-length relationships are sensitive to the sample size and composition. We investigated this issue by comparing estimates of mean back-calculated lengths at age and growth rates derived from subsets of a large sample of wild channel catfish Ictalurus punctatus (N=788) collected in 2001 and 2002 from 9 rivers in Mississippi, United States. Estimates of growth rate varied among subsets consisting of individual year class (2-6) of channel catfish separated from the overall sample. For nine subsets, comprising randomly-selected and increasing proportions of the overall sample (20%-100% at 10% increments of the overall sample), growth was similar. However, growth differed for a subset representing a random 10% of the overall sample. Lengths at age and growth rates derived from each of the 2001 and 2002 components of the sample both differed. All results were significant at P < 0.05. PMID:24575181

  7. Back-calculation of surface acceleration from penetration resistances at liquefied sites of 1956 Dunaharaszti earthquake, in Hungary

    Science.gov (United States)

    Bán, Zoltán; Győri, Erzsébet; Horváth, Tibor

    2015-04-01

    Liquefaction and paleoliquefaction studies are being used increasingly to interpret ground motion parameters (acceleration, magnitude, epicenter location) in regions that experience infrequent but damaging earthquakes. These are especially applicable where the most recent damaging earthquakes occurred prior to the development of ground motion instrumentation. In Hungary, a damaging earthquake of magnitude 5.6 occurred in Dunaharaszti in 1956. Its epicenter was located about 5 km from the southern boundary of Budapest. The quake caused serious damages in the epicentral area and in the southern districts of the capital. A Wiechert type seismometer was operated in Budapest 15-20 km from the epicenter but it saturated by the earthquake so instrumental information does not exist about the shaking strength. Ground accelerations caused by the event can be deduced only from the macroseismic intensity values and from the analogies of recent similar earthquakes where strong motion data exist. The epicentral area of Dunaharaszti earthquake was located along the Danube River. Sand boils were observed in some locations that indicated the occurrence of liquefaction. Because their exact locations were recorded at the time of the earthquake, geotechnical measurements could be performed. Therefore an alternative possibility to estimate shaking strength can be the back-analysis of liquefaction field data. Unlike the paleoliquefaction studies, in our case the source of the earthquake and the magnitude is known, our purpose was only to estimate the peak ground acceleration and acceleration-related parameters, such as Arias intensity. Back-calculation of surface acceleration was performed at two locations, where evidences of liquefaction had been observed after the earthquake. On both locations SPT and CPT measurements were carried out, and back-analysis from them was performed with different empirical methods. This allowed the assessment of the selected method's and the used in

  8. 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......, which is supposed to be critical in determining recruitment strength in Baltic sprat....

  9. 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.

  10. 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.

  11. 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...

  12. 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,

  13. Estimation of axial stiffness of plant fibres from compaction of non-woven mats

    DEFF Research Database (Denmark)

    Gamstedt, E. K.; Bommier, E.; Madsen, Bo

    2014-01-01

    Plant fibres are known to show a large variability in stiffness, which makes it time-consuming to experimentally characterize this property by conventional tensile testing. In this work, an alternative method is used, where the average fibre stiffness is back-calculated from compaction tests of in...

  14. 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

  15. Considerations for estimating daily intake values of non-persistent environmental endocrine disruptors based on urinary biomonitoring data

    DEFF Research Database (Denmark)

    Søeborg, Tue; Frederiksen, Hanne; Andersson, Anna-Maria

    2014-01-01

    into daily intake values for bisphenol A, phthalates, parabens and triclosan, and to identify knowledge gaps.MethodsHuman data was evaluated and supplied with relevant animal data. Focus was on recovery of the administered dose, the route of administration and on differences between humans and animals...... due to extensive metabolism. In animals using 14C-marked phthalates, near-complete recovery is observed. An oral dose of 14C-marked parabens is also almost completely recovered in animals. In both humans and animals however, two unspecific metabolites are formed, which complicates the back......-calculation of parabens in humans. The recovery of both oral and dermal triclosan in humans has been studied, but due to background levels of triclosan, the back-calculation is difficult to perform.ConclusionDue to limited data, reasonable estimates of daily intake values based on urinary data are often not possible...

  16. 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%.

  17. 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.

  18. 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.

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

    OpenAIRE

    Paulo Duarte-Neto; Fábio M. Higa; Rosangela P. Lessa

    2012-01-01

    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 t...

  20. 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.

  1. 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 ...

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

    OpenAIRE

    Hoffmann, Friederike; Roy, Hans; Bayer, Kristina; Hentschel, Ute; Pfannkuchen, Martin; Franz BRÜMMER; de Beer, Dirk

    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 oxy...

  3. Seroincidence of non-typhoid Salmonella infections

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  4. 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...

  5. Echolocation signals of wild harbour porpoises, Phocoena phocoena

    DEFF Research Database (Denmark)

    Villadsgaard, A.; Wahlberg, Magnus; Tougaard, J.

    2007-01-01

    Field recordings of harbour porpoises (Phocoena phocoena) were made in the inner Danish waters with a vertical array of three or four hydrophones. The back-calculated source level ranged from 178 to 205 dB re 1 µPa pp @ 1 m with a mean source level of 191 dB re 1 µPa pp @ 1 m. The maximum source ...... be detectable by porpoise detectors over significantly larger distances than had previously been assumed. Harbour porpoises in this study preferred a relatively constant inter-click interval of about 60 ms, but intervals up to 200 ms and down to 30 ms were also recorded....

  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. High-resolution structure of an HIV zinc fingerlike domain via a new NMR-based distance geometry approach

    International Nuclear Information System (INIS)

    A new method is described for determining molecular structures from NMR data. The approach utilizes 2D NOESY back-calculations to generate simulated spectra for structures obtained from distance geometry (DG) computations. Comparison of experimental and back-calculated spectra, including analysis of cross-peak buildup and auto-peak decay with increasing mixing time, provides a quantitative measure of the consistence between the experimental data and generated structures and allows for use of tighter interproton distance constraints. For the first time, the goodness of the generated structures is evaluated on the basis of their consistence with the actual experimental data rather than on the basis of consistence with other generated structures. This method is applied to the structure determination of an 18-residue peptide with an amino acid sequence comprising the first zinc fingerlike domain from the gag protein p55 of HIV. This is the first structure determination to atomic resolution for a retroviral zinc fingerlike complex. The peptide [Zn(p55F1)] exhibits a novel folding pattern that includes type I and type II NH-S tight turns and is stabilized both by coordination of the three Cys and one His residues to zinc and by extensive internal hydrogen bonding. The backbone folding is significant different from that of a classical DNA-binding zinc finger. The side chains of conservatively substituted Phe and Ile residues implicated in genomic RNA recognition form a hydrophobic patch on the peptide surface

  8. 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.

  9. 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.

  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. Integrated Force Method Solution to Indeterminate Structural Mechanics Problems

    Science.gov (United States)

    Patnaik, Surya N.; Hopkins, Dale A.; Halford, Gary R.

    2004-01-01

    Strength of materials problems have been classified into determinate and indeterminate problems. Determinate analysis primarily based on the equilibrium concept is well understood. Solutions of indeterminate problems required additional compatibility conditions, and its comprehension was not exclusive. A solution to indeterminate problem is generated by manipulating the equilibrium concept, either by rewriting in the displacement variables or through the cutting and closing gap technique of the redundant force method. Compatibility improvisation has made analysis cumbersome. The authors have researched and understood the compatibility theory. Solutions can be generated with equal emphasis on the equilibrium and compatibility concepts. This technique is called the Integrated Force Method (IFM). Forces are the primary unknowns of IFM. Displacements are back-calculated from forces. IFM equations are manipulated to obtain the Dual Integrated Force Method (IFMD). Displacement is the primary variable of IFMD and force is back-calculated. The subject is introduced through response variables: force, deformation, displacement; and underlying concepts: equilibrium equation, force deformation relation, deformation displacement relation, and compatibility condition. Mechanical load, temperature variation, and support settling are equally emphasized. The basic theory is discussed. A set of examples illustrate the new concepts. IFM and IFMD based finite element methods are introduced for simple problems.

  12. Sewage epidemiology--a real-time approach to estimate the consumption of illicit drugs in Brussels, Belgium.

    Science.gov (United States)

    van Nuijs, Alexander L N; Mougel, Jean-François; Tarcomnicu, Isabela; Bervoets, Lieven; Blust, Ronny; Jorens, Philippe G; Neels, Hugo; Covaci, Adrian

    2011-04-01

    The sewage epidemiology approach was applied to a one-year sampling campaign in the largest wastewater treatment plant (WWTP) in Belgium. The consumption of cocaine (COC), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methamphetamine (METH), methadone (MTD) and heroin (HER) was evaluated based on measured concentrations of the parent compound and/or metabolites in daily 24-hour composite influent wastewater samples. The inevitable back-calculations used in the sewage epidemiology approach were adapted to newly available information regarding the stability of the compounds in wastewater and the excretion pattern of illicit drugs. For COC, three different back-calculation approaches were evaluated. In addition, for the first time, efforts were made to calculate the number of inhabitants living in the catchment area of the WWTP in a real-time and dynamic way, based on concentrations of nitrogen, phosphorus and oxygen in the wastewater samples. Clear variations in the amount of inhabitants in the catchment area of the WWTP were observed. For COC, AMP and MDMA a significant higher weekend use was observed while for HER and MTD no significant daily variations could be found. METH consumption was negligible. Generally, the sewage epidemiology calculations were in agreement with official statistics. This manuscript shows that sewage epidemiology provides consistent and logical results and that it is a promising tool that can be used in addition to classical studies to estimate illicit drug use in populations. Therefore, efforts should be made to further optimize this approach in the future. PMID:21257204

  13. Comparison of soil moisture fields estimated by catchment modelling and remote sensing: a case study in South Africa

    Directory of Open Access Journals (Sweden)

    T. Vischel

    2007-07-01

    Full Text Available The paper compares two independent approaches to estimate soil moisture at the regional scale over a 4625 km2 catchment (Liebenbergsvlei, South Africa. The first estimate is derived from a physically-based hydrological model (TOPKAPI. The second estimate is derived from the scatterometer on board on the European Remote Sensing satellite (ERS. Results show a very good correspondence between the modelled and remotely sensed soil moisture, illustrated over two selected seasons of 8 months by regression R2 coefficients lying between 0.78 and 0.92. Such a close similarity between these two different, independent approaches is very promising for (i remote sensing in general (ii the use of hydrological models to back-calculate and disaggregate the satellite soil moisture estimate and (iii for hydrological models to assimilate the remotely sensed soil moisture.

  14. Childhood exposure to DEHP, DBP and BBP under existing chemical management systems: A comparative study of sources of childhood exposure in Korea and in Denmark

    DEFF Research Database (Denmark)

    Lee, Jihyun; Lee, Jong-Hyeon; Kim, Chan-Kook;

    2014-01-01

    an exposure scenario approach. Then, the scenario based exposure level was compared with back-calculated exposure levels based on biomonitored urinary phthalate metabolite concentrations. The result verifies the existence of varying territorial human background exposure levels and the gap between......, while Korea produces more than 0.4 million tons of the three above-mentioned phthalates each year. First, a comparative review of the existing phthalate regulations in the two countries was performed. Next, the level of childhood phthalate exposure from environmental and food sources was estimated using...... exposure estimations based on exposure modeling and biomonitoring data. Cumulative childhood risk levels in Denmark were lower than in Korea. For both countries, risk levels from back calculation were higher than those from scenario estimation. The median cumulative risk levels from scenario estimation and...

  15. First evaluation of illicit and licit drug consumption based on wastewater analysis in Fort de France urban area (Martinique, Caribbean), a transit area for drug smuggling.

    Science.gov (United States)

    Damien, Devault A; Thomas, Néfau; Hélène, Pascaline; Sara, Karolak; Yves, Levi

    2014-08-15

    Drugs of abuse are increasingly consumed worldwide. Such consumption could be back-calculated based on wastewater content. The West Indies, with its coca production and its thriving illicit drug market, is both a hub of world cocaine trafficking and a place where its consumption is prevalent particularly in the form of crack. The present study will firstly investigate Caribbean consumption by a daily 5 to 7 day sampling campaign of composite wastewater samples from the four wastewater treatment plants of the Martinique capital, including working and non-working periods. The local consumption of cocaine is ten to thirty times higher than OECD standards because of the prevalence of crack. The excretion coefficient for crack consumption and the impact of temperature on drug stability need further investigation. However, the low diversity of illicit drugs consumed and the crack prevalence suggest practices driven by the transiting of drugs for international trafficking. PMID:24914526

  16. 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.

  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

    efficiency of the jute fibers. The elastic modulus of neat PLA is constant until a temperature of about 45C, after which it is decreased rapidly. For neat CA, the elastic modulus is almost constant in the whole temperature range. The maximum stress of the neat biopolymers is consistently reduced. 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 of the......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. 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...

  19. A model for tides and currents in the English Channel and southern North Sea

    Science.gov (United States)

    Walters, Roy A.

    1987-01-01

    The amplitude and phase of 11 tidal constituents for the English Channel and southern North Sea are calculated using a frequency domain, finite element model. The governing equations - the shallow water equations - are modifed such that sea level is calculated using an elliptic equation of the Helmholz type followed by a back-calculation of velocity using the primitive momentum equations. Triangular elements with linear basis functions are used. The modified form of the governing equations provides stable solutions with little numerical noise. In this field-scale test problem, the model was able to produce the details of the structure of 11 tidal constituents including O1, K1, M2, S2, N2, K2, M4, MS4, MN4, M6, and 2MS6.

  20. The imprint of anthropogenic CO2 emissions on Atlantic bluefin tuna otoliths

    Science.gov (United States)

    Fraile, Igaratza; Arrizabalaga, Haritz; Groeneveld, Jeroen; Kölling, Martin; Santos, Miguel Neves; Macías, David; Addis, Piero; Dettman, David L.; Karakulak, Saadet; Deguara, Simeon; Rooker, Jay R.

    2016-06-01

    Otoliths of Atlantic bluefin tuna (Thunnus thynnus) collected from the Mediterranean Sea and North Atlantic Ocean were analyzed to evaluate changes in the seawater isotopic composition over time. We report an annual otolith δ13C record that documents the magnitude of the δ13C depletion in the Mediterranean Sea between 1989 and 2010. Atlantic bluefin tuna in our sample (n = 632) ranged from 1 to 22 years, and otolith material corresponding to the first year of life (back-calculated birth year) was used to reconstruct seawater isotopic composition. Otolith δ18O remained relatively stable between 1989 and 2010, whereas a statistically significant decrease in δ13C was detected across the time interval investigated, with a rate of decline of 0.05‰ yr- 1 (- 0.94‰ depletion throughout the recorded period). The depletion in otolith δ13C over time was associated with the oceanic uptake of anthropogenically derived CO2.

  1. Linking growth to environmental histories in central Baltic young-of-the-year sprat, Sprattus sprattus : an approach based on otolith microstructure analysis and hydrodynamic modelling

    DEFF Research Database (Denmark)

    Baumann, H.; Hinrichsen, H.H.; Voss, R.; Stepputtis, D.; Grygiel, W.; Worsøe Clausen, Lotte; Temming, A.

    2006-01-01

    Otolith microstructure analysis and hydrodynamic modelling were combined to study growth patterns in young-of-the-year (YoY) sprat, Sprattus sprattus, which were sampled in October 2002 in the central Baltic Sea. The observed 'window of survival', approximated by the distribution of back...... predominantly comprised of individuals which grew faster during the larval stage. Daily mean temperatures, experienced across the entire YoY population, were derived from Lagrangian particle simulations and correlated with (1) detrended otolith growth and (2) back-calculated, daily somatic growth rates of...... survivors. The results showed that abrupt changes in ambient temperature can be detected in the seasonal pattern of otolith growth, and that higher temperatures led to significantly faster growth throughout the entire age range of YoY sprat...

  2. Heat conductivity of buffer materials

    International Nuclear Information System (INIS)

    The report deals with the thermal conductivity of bentonite based buffer materials. An improved technique for measuring the thermal conductivity of buffer materials is described. Measurements of FLAC calculations applying this technique have led to a proposal of how standardized tests should be conducted and evaluated. The thermal conductivity of bentonite with different void ratio and degree of water saturation has been determined in the following different ways: * Theoretically according to three different investigations by other researchers. * Laboratory measurements with the proposed method. * Results from back-calculated field tests. Comparison and evaluation showed that these results agreed very well, when the buffer material was almost water saturated. However, the influence of the degree of saturation was not very well predicted with the theoretical methods. Furthermore, the field tests showed that the average thermal conductivity in situ of buffer material (compacted to blocks) with low degree of water saturation was lower than expected from laboratory tests. 12 refs, 29 figs, 11 tabs

  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. 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.

  5. Biotransformation kinetics and sorption of cocaine and its metabolites and the factors influencing their estimation in wastewater.

    Science.gov (United States)

    Plósz, Benedek Gy; Reid, Malcolm J; Borup, Morten; Langford, Katherine H; Thomas, Kevin V

    2013-05-01

    The quantitative analysis of human urinary metabolites as biomarkers in wastewater streams has been used to estimate the rates of illicit drug use in the wider community. The primary underlying assumption in such studies is that a sample of wastewater is equivalent to a cumulative sample of urine. Drug metabolism in humans is predominantly enzymatically mediated, but these processes are not exclusive to the human body, and are found to occur in the environment and the sewer network. Understanding what happens to drugs and their urinary metabolites in the sewer system between the point of excretion and sampling is particularly important since it is possible that in-sewer transformation may influence final biomarker concentration. The present study uses batch experiments to measure and assess the biotransformation processes of cocaine and its two major human metabolites, benzoylecgonine and ecgonine methyl ester. The activated sludge modelling framework for xenobiotic organic micro-pollutants (ASM-X) is used for model structure identification and calibration. Biotransformation was observed to follow pseudo first-order kinetics. The biodegradation kinetics of cocaine, benzoylecgonine and ecgonine methyl ester is not significantly affected by the availability of dissolved oxygen. Results obtained in this study show that omitting in-pipe biotransformation affects the accuracy of back-calculated cocaine use estimates. This varies markedly depending on the in-sewer hydraulic retention time, total biomass concentration and the relative concentration of each metabolite. However, back-calculated cocaine use estimates derived from wastewater concentrations of benzoylecgonine and ecgonine methyl ester do show very close agreement if ex-vivo biotransformation of these compounds is considered. PMID:23453589

  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. 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

  8. Concentration-time profiles of gamma-hydroxybutyrate in blood after recreational doses are best described by zero-order rather than first-order kinetics.

    Science.gov (United States)

    Jones, A W; Eklund, A; Kronstrand, R

    2009-01-01

    The recreational drug gamma-hydroxybutyrate (GHB) has a short plasma elimination half-life (t(1/2)) reported to be about 30-50 min. However, this represents a terminal half-life and therefore might not necessarily apply after large (abuse) doses are taken. Clinical studies with sodium oxybate (sodium salt of GHB) suggest that zero-order rather than first-order kinetics are more appropriate to describe post-peak concentration-time (C-T) profiles. We report the case of a 23-year-old male found unconscious by the police and a blood sample contained 100 mg/L GHB and 0.14 g% ethanol. On regaining consciousness the man admitted drinking alcohol about 6 h earlier but claimed that his drink must have been spiked with GHB. The police wanted to know how much GHB had been administered to account for the man's clinical condition. A back-calculation for 6 h, assuming a GHB half-life of 40 min, gives a very high concentration in blood of approximately 900 mg/L, which would probably have proven fatal. Back-calculating using zero-order kinetics and a proposed elimination rate of 18 mg/L per hour leads to a GHB concentration of 208 mg/L, which is much more realistic. Toxicologists should not arbitrarily apply the principles of first-order kinetics after abuse doses of drugs, when zero-order or saturation kinetics (Michaelis-Menten) are more appropriate. PMID:19653937

  9. Life history attributes of fishes along the latitudinal gradient of the Missouri River

    Science.gov (United States)

    Braaten, P.J.; Guy, C.S.

    2002-01-01

    Populations of two short-lived species (emerald shiner Notropis atherinoides and sicklefin chub Macrhybopsis meeki) and three long-lived species (freshwater drum Aplodinotus grunniens, river carpsucker Carpiodes carpio, and sauger Stizostedion canadense) were studied in the Missouri River to examine spatial variations in life history characteristics across a latitudinal and thermal gradient (38??47???N to 48??03???N). The life history characteristics included longevity (maximum age), the rate at which asymptotic length was approached (K from the von Bertalanffy growth equation), the mean back-calculated length at age, and growth rates during the first year of life (mm/degree-day and mm/d). The mean water temperature and number of days in the growing season averaged 1.3 times greater in the southern than in the northern latitudes, while degree-days averaged twice as great. The longevity of all species except freshwater drum increased significantly from south to north, but the relationships between maximum age and latitude were curvilinear for short-lived species and linear for long-lived species. The von Bertalanffy growth coefficient for river carpsuckers and saugers increased from north to south, as indicated by significant negative relationships between K and latitude. Mean back-calculated length at age was negatively related to latitude for freshwater drums (???age 4) and saugers (ages 1-5) but positively related to latitude for river carpsuckers (???age 6). One of the growth rates examined (mm/degree-day) increased significantly from low to high latitudes for emerald shiners, sicklefin chubs, freshwater drums, and river carpsuckers during the first growing season. The other growth rate (mm/d) increased significantly from low to high latitudes for emerald shiners but was inversely related to latitude for saugers. These results suggest that the thermal regime related to latitude influences the life history characteristics of fishes in the Missouri River.

  10. 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

  11. 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.

  12. Preliminary Constraints on Fossil-fuel CO2: Comparison of Tracers CO and SF6 With Measurements of 14CO2

    Science.gov (United States)

    Turnbull, J. C.; Miller, J. B.; Lehman, S. J.; Sparks, R. J.; Tans, P. P.

    2004-12-01

    CO2 derived from the combustion of fossil fuels is a significant component of the carbon balance of North America. However, on the sub-continental spatial scales and sub-annual time scales relevant to the objectives of the North American Carbon Program, estimates of combustion CO2 from traditional economic inventories are unlikely to be accurate, and may contribute to biases in the interpretation of atmospheric CO2 measurements. Indirect estimates of the combustion CO2 component can also be obtained from measured CO:CO2 ratios and SF6:CO2 ratios. The low cost and ease of measurement allow the application of these methods in intensive measurement campaigns. However, the accuracy of the combustion CO2 detection capability relies on accurately determining the emission ratio of CO:CO2 or SF6:CO2 at relevant time and space scales. In the case of CO, atmospheric chemical biases and non fossil fuel sources must also be understood. CO2 derived from fossil fuels contains no 14C, whereas other sources have a 14C content close to that of ambient air. Measurement of the 14C content in CO2 thus provides a direct tracer for fossil fuel derived CO2, without the biases associated with the indirect tracer methods. We used high-precision accelerator mass spectrometry to determine the 14C content of CO2 at several North American sites (Niwot Ridge, CO, Harvard Forest, MA and New Hampshire) during 2003 and 2004, and calculate the fossil fuel CO2 contribution in each case. We compare these results with CO:CO2 and SF6:CO2 measurements on the same samples to evaluate the indirect tracer methods at these sites. Preliminary results for wintertime measurements (when biological CO2 exchange fluxes are small) support the accuracy of the 14C method. The back-calculated emission ratios for SF6:CO2 vary significantly and consistently underestimate the global average. While the back-calculated CO:CO2 ratios are more consistent, they also underestimate the predicted values from emissions

  13. 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

  14. 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

  15. Mine-by experiment committee report phase 1: excavation response summary and implications

    International Nuclear Information System (INIS)

    The first phase of the Mine-by Experiment, i.e., excavation of a 3.5-m-diameter tunnel, was carried out at the 420 Level of the Underground Research Laboratory to investigate rock mass damage and progressive failure around a circular opening in brittle unfractitred Lac du Bonnet granite. The tunnel was excavated without explosives, and state-of-the-art instrumentation comprising both geomechanical and geophysical instruments was used to monitor the failure process. The experiment showed that rock mass damage begins once the deviatoric stress (0'1 - 0'3) near the advancing face of the tunnel exceeds a critical level. Crack propagation can lead to progressive failure around the tunnel; however, it is limited to a region, referred to as the excavation damaged zone, of less than one tunnel radius. Within the damaged zone, stabbing (a typical form of brittle failure) began at stress levels equivalent to about 50% of the short-term laboratory unconfined compressive strength. This reduction in strength between laboratory and in situ conditions occurs because the in situ loading path is far more complex than the monotonic loading path used to test laboratory samples. There is no evidence to suggest that the stabbing failure process would extend beyond the depth of damage defined by the deviatoric stress criterion. The stabbing process stops when the tunnel face has advanced sufficiently (approximately 2 tunnel diameters) such that the rock mass is no longer subjected to excavation-induced stress changes. The strength of the rock mass in the damaged zone must be back-calculated from in situ tests, because the loading path cannot be duplicated readily in the laboratory. Thus, the back-calculated damaged strength must be used to evaluate the stability of the excavation. Sealing systems to reduce the permeability in the axial direction of a tunnel must be keyed into the rock mass beyond the radial extent of the damaged zone. The shape of the seals must be designed so as to

  16. 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.

  17. 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

  18. 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

  19. 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

  20. MQ-HNCO-TROSY for the measurement of scalar and residual dipolar couplings in larger proteins: application to a 557-residue IgFLNa16-21

    Energy Technology Data Exchange (ETDEWEB)

    Maentylahti, Sampo [University of Helsinki, NMR Laboratory, Program in Structural Biology and Biophysics, Institute of Biotechnology/NMR Laboratory (Finland); Koskela, Outi [University of Helsinki, Laboratory of Organic Chemistry, Department of Chemistry (Finland); Jiang, Pengju [University of Oxford, Biochemistry Department (United Kingdom); Permi, Perttu, E-mail: Perttu.Permi@helsinki.f [University of Helsinki, NMR Laboratory, Program in Structural Biology and Biophysics, Institute of Biotechnology/NMR Laboratory (Finland)

    2010-07-15

    We describe a novel pulse sequence, MQ-HNCO-TROSY, for the measurement of scalar and residual dipolar couplings between amide proton and nitrogen in larger proteins. The experiment utilizes the whole 2T{sub N} polarization transfer delay for labeling of {sup 15}N chemical shift in a constant time manner, which efficiently doubles the attainable resolution in {sup 15}N dimension with respect to the conventional HNCO-TROSY experiment. In addition, the accordion principle is employed for measuring (J + D){sub NH}s, and the multiplet components are selected with the generalized version of the TROSY scheme introduced by Nietlispach (J Biomol NMR 31:161-166, 2005). Therefore, cross peak overlap is diminished while the time period during which the {sup 15}N spin is susceptible to fast transverse relaxation associated with the anti-TROSY transition is minimized per attainable resolution unit. The proposed MQ-HNCO-TROSY scheme was employed for measuring RDCs in high molecular weight protein IgFLNa16-21 of 557 residues, resulting in 431 experimental RDCs. Correlations between experimental and back-calculated RDCs in individual domains gave relatively low Q-factors (0.19-0.39), indicative of sufficient accuracy that can be obtained with the proposed MQ-HNCO-TROSY experiment in high molecular weight proteins.

  1. Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

    Science.gov (United States)

    Heffernan, J.B.; Albertin, A.R.; Fork, M.L.; Katz, B.G.; Cohen, M.J.

    2011-01-01

    Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N2 is highly variable in space and inversely correlated with dissolved oxygen (O2). Negative relationship between O2 and ??15NNO 3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15N: 18O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32% of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source ??15NNO 3 based on denitrification progression suggest that isotopically-enriched nitrate (NO3-) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs. ?? Author(s) 2011.

  2. 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

  3. 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.

  4. Pulse propagation in the pulmonary arteries

    Science.gov (United States)

    Hill, Nicholas; Vaughan, Gareth; Olufsen, Mette; Johnson, Martin; Sainsbury, Christopher

    2007-11-01

    The model of Olufsen [1,2] has been extended to study pulse propagation in the pulmonary circulation. The pulmonary arteries are treated as a bifurcating tree of compliant and tapering vessels. The model is divided into two coupled parts: the larger and smaller arteries. Blood flow and pressure in the larger arteries are predicted from a nonlinear 1D cross-sectional area-averaged model for a Newtonian fluid in an elastic tube. The initial cardiac output is obtained from magnetic resonance measurements. The smaller blood vessels are modelled as an asymmetric structured tree with specified area and asymmetry ratios between the parent and daughter arteries. Womersley's theory gives the wave equation in the frequency domain for the 1D flow in these smaller vessels, resulting in a linear system. The impedances of the smallest vessels are set to a constant and then back-calculation gives the required outflow boundary condition for the Navier-Stokes equations in the larger vessels. The number of generations of blood vessels, and the compliance of the arterial wall are shown to affect both the systolic and diastolic pressures. [1] Olufsen MS et al. Ann Biomed Eng. 2000;28:1281-99. [2] Olufsen MS. Am J Physiol. 1999;276:H257-68.

  5. 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

  6. 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

  7. 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

  8. Finite-element modelling of geomechanical and hydraulic responses to the room 209 heading extension excavation response experiment 2: post-excavation analysis of experimental results

    International Nuclear Information System (INIS)

    An in situ excavation response test was conducted at the 240 Level of the Underground Research Laboratory (URL) in conjunction with the excavation of a tunnel (Room 209) through a narrow, near-vertical, water-bearing fracture oriented almost perpendicular to the tunnel axis. This report presents a post-excavation analysis of the predicted mechanical response of the granitic rock mass to the tunnel excavation and the near-field hydraulic response of the fracture zone, compares the numerical modelling predictions with the actual measured response, provides information on the rock mass and fracture from back-analysis of the responses, and makes recommendations for future experiments. Results indicate that displacements and stress changes were reasonably well predicted. Pressure drops at hydrology boreholes and inflow to the tunnel were overpredicted, and fracture permeability changes were underpredicted. The permeability change is considered too large to be solely stress-induced. The back-calculated deformation modulus indicated nonlinear softening of the rock within 3.5 m of the tunnel wall. This is likely due to both excavation damage and the confining stress dependence of the modulus. For future excavation experiments it is recommended that mechanical excavation should replace the drill-and-blast technique; excavation damage should be incorporated into mechanical models; an improved hydraulic fracture model should be developed; and a coupled geomechanical-hydraulic analysis of fracture flow should be developed. (author). 16 refs., 15 tabs., 156 figs

  9. Atomic Emission, Absorption and Fluorescence in the Laser-induced Plasma

    International Nuclear Information System (INIS)

    The main result of our efforts is the development and successful application of the theoretical model of laser induced plasma (LIP) that allows a back-calculation of the composition of the plasma (and the condensed phase) based on the observable plasma spectrum. The model has an immediate experimental input in the form of LIP spectra and a few other experimentally determined parameters. The model is also sufficiently simple and, therefore, practical. It is conveniently interfaced in a graphical user-friendly form for using by students and any laboratory personnel with only minimal training. In our view, the model opens up the possibility for absolute analysis, i.e. the analysis which requires no standards and tedious calibration. The other parts of this proposal (including plasma diagnostics) were somewhat subordinate to this main goal. Plasma diagnostics provided the model with the necessary experimental input and led to better understanding of plasma processes. Another fruitful direction we pursued was the use of the correlation analysis for material identification and plasma diagnostics. Through a number of computer simulations we achieved a clear understanding of how, where and why this approach works being applied to emission spectra from a laser plasma. This understanding will certainly improve the quality of forensic and industrial analyses where fast and reliable material identification and sorting are required

  10. 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

  11. 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.

  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. Geochemistry and evolution of MORB-type eclogites from the Muenchberg Massif, southern Germany

    International Nuclear Information System (INIS)

    In the Muenchberg Massif in the Variscan foldbelt of southern Germany two varieties of eclogite are known which are intercalated with amphibolite-facies meta-igneous and meta-sedimentary rocks: a dark kyanite-free and a lighter colored kyanite-bearing type. Kyanite-free eclogites, which are discussed here, have a major and trace element composition which suggests derivation from ocean-floor basalts with melt to cumulate compositions. Internal Sm-Nd isochroms (clinopyroxene-amphibole-garnet) and one Rb-Sr isochron (clinopyroxene-amphibole-mica) yield eclogitization ages in the range of 380 to 395 Ma. Thus, the age of eclogitization is only marginally higher (Nd of 8.7 ± 0.6 and is likely to record the age of igneous formation of the eclogite protoliths. Sr isotopic compositions back-calculated to that time are anomalously high and variable if compared to Nd isotopes. This can be explained by alteration with an aqueous or fluid phase with high 87Sr/86Sr, most likely seawater, either during igneous formation in an oceanic rift environment or subduction-related eclogitization. In addition, some eclogites show a marked enrichment of incompatible, immobile elements and plot far below the whole-rock Sm-Nd isochron. These features are ascribed to the presence of an evolved crustal component, probably acquired during extrusion of the basaltic protoliths by mixing with country-rock gneisses. (orig.)

  14. 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.

  15. 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.

  16. 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.

  17. C terminal retroviral-type zinc finger domain from the HIV-1 nucleocapsid protein is structurally similar to the N-terminal zinc finger domain

    International Nuclear Information System (INIS)

    Two-dimensional NMR spectroscopic and computational methods were employed for the structure determination of an 18-residue peptide with the amino acid sequence of the C-terminal retriviral-type (r.t.) zinc finger domain from the nucleocapsid protein (NCP) of HIV-1 [Zn(HIV1-F2)]. Unlike results obtained for the first retroviral-type zinc finger peptide, Zn (HIV1-F1) broad signals indicative of confomational lability were observed in the 1H NMR spectrum of An(HIV1-F2) at 25 C. The NMR signals narrowed upon cooling to -2 C, enabling complete 1H NMR signal assignment via standard two-dimensional (2D) NMR methods. Distance restraints obtained from qualitative analysis of 2D nuclear Overhauser effect (NOESY) data were sued to generate 30 distance geometry (DG) structures with penalties in the range 0.02-0.03 angstrom 2. All structures were qualitatively consistent with the experimental NOESY spectrum based on comparisons with 2D NOESY back-calculated spectra. These results indicate that the r.t. zinc finger sequences observed in retroviral NCPs, simple plant virus coat proteins, and in a human single-stranded nucleic acid binding protein share a common structural motif

  18. Pavement evaluation and rehabilitation

    Energy Technology Data Exchange (ETDEWEB)

    Ali, N.A.; Khosla, N.P.; Johnson, E.G.; Hicks, R.G.; Uzan, J.

    1987-01-01

    The 20 papers in this report deal with the following areas: determination of layer moduli using a falling weight deflectometer; evaluation of effect of uncrushed base layers on pavement performance; the effect of contact area shape and pressure distribution on multilayer systems response; sensitivity analysis of selected backcalculation procedures; performance of a full-scale pavement design experiment in Jamaica; subsealing and load-transfer restoration; development of a demonstration prototype expert system for concrete pavement evaluation; numerical assessment of pavement test sections; development of a distress index and rehabilitation criteria for continuously reinforced concrete pavements using discriminant analysis; a mechanistic model for thermally induced reflection cracking of portland cement concrete pavement with reinforced asphalt concrete overlay; New Mexico study of interlayers used in reflective crack control; status of the South Dakota profilometer; incorporating the effects of tread pattern in a dynamic tire excitation mechanism; external methods for evaluating shock absorbers for road-roughness measurements; factor analysis of pavement distresses for surface condition predictions; development of a utility evaluation for nondestructive-testing equipment used on asphalt-concrete pavements; estimating the life of asphalt overlays using long-term pavement performance data; present serviceability-roughness correlations using rating panel data; video image distress analysis technique for Idaho transportation department pavement-management system; acceptability of shock absorbers for road roughness-measuring trailers.

  19. 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.

  20. 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.

  1. 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.

  2. Bayesian inference of protein structure from chemical shift data

    Directory of Open Access Journals (Sweden)

    Lars A. Bratholm

    2015-03-01

    Full Text Available 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 Monte Carlo simulations of three small proteins (ENHD, Protein G and the SMN Tudor Domain using the PROFASI force field and the chemical shift predictor CamShift. Using a clustering-criterion for identifying the best structure, together with the addition of a solvent exposure scoring term, the simulations suggests that sampling both the structure and the uncertainties in chemical shift prediction leads more accurate structures compared to conventional methods using empirical determined weights. The Cauchy distribution, using either sampled uncertainties or predetermined weights, did, however, result in overall better convergence to the native fold, suggesting that both types of distribution might be useful in different aspects of the protein structure prediction.

  3. 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.

  4. A review of marine anthropogenic CO2 definitions: introducing a thermodynamic approach based on observations

    International Nuclear Information System (INIS)

    A review of existing methods that define anthropogenic CO2 as deduced from total inorganic carbon is presented. A refined approach to define anthropogenic CO2 is introduced that has a stronger thermodynamic orientation than current methods, and is based on a back-calculation technique by Chen and Millero and Poisson and Chen. Anthropogenic CO2 results of the new technique are compared with results from the original technique as well as with results of the technique of Gruber et al. The new technique is furthermore applied to three time-separated data sets in the subpolar North Atlantic and shows consistent results with regard to available data quality and anthropogenic CO2 quantities. The difference between the new thermodynamic approach and the anthropogenic CO2 definition of Gruber et al., which is termed mechanistic, is discussed. Here likely changes in the CO2 solubility pump are a thermodynamic property of this definition, whereas it is a separate phenomenon in the mechanistic definition. The thermodynamic approach is not without caveats, but points to improvements by the synergistic use of model results and those from observations. Future improvements are considered for the initial saturation state of oxygen and CO2, at the instant the surface water loses contact with the atmosphere and for variations in the Redfield ratio

  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. Growth and reproductive properties of Tench, Tinca tinca Linnaeus, 1758 in Trasimeno Lake (Umbria, Italy

    Directory of Open Access Journals (Sweden)

    Pompei L.

    2012-10-01

    Full Text Available Growth and some reproductive properties of native Tinca tinca Linnaeus, 1758 from Trasimeno Lake were investigated during 2009 and 2010. The total sample of fish (510 was composed by 126 males, 221 females and 163 immature specimens. Total length (TL ± 0.1 cm and weight (W ± 0.1 g were recorded; age estimation was based on scalimetry and sex was determined by microscopic observation of the gonads. Age composition varied from 1+  to 11+ . The TL-W relationship was log 10W =  −2.235 + 3.248log 10TL. Previous growth was determined with back-calculation from scale measurements using the Fraser-Lee method. Theoretical length growth was estimated with von Bertalanffy’s model. Analysis of the gonadosomatic index (GSI suggests that the reproductive period of the population took place from May to July. Sexual maturation occurred in both sexes at the second year of life. The mean diameter of eggs was 0.075 mm. The mean number of eggs produced by each female was 233 930 and increased with the size of the specimens. Though it is one of the most widespread and interested species in fishing in Italian waters, tench has not been widely studied; this research deepens some biological characteristics of this species that is strongly shrinking in Italy.

  8. Groundwater Effect on Faulted Rock Mass: An Evaluation of Modi Khola Pressure Tunnel in the Nepal Himalaya

    Science.gov (United States)

    Shrestha, Pawan Kumar; Panthi, Krishna Kanta

    2014-05-01

    Groundwater has a negative impact not only in construction activity, but also in stability of a tunnel. Severity increases particularly in tunnels passing through fault gouge and breccia, where rock material is completely crushed and extremely weak. Instantaneous collapse and excessive plastic deformation is most likely in tunnels passing through such zones. Often, `flowing' conditions may prevail if groundwater is mixed in the rock mass. This paper presents one such tunnel case in the Nepal Himalaya; i.e. the Modi pressure tunnel. This pressure tunnel passes through a tectonic fault consisting of gouge material. High deformation in the tunnel was observed while excavating the tunnel through the fault. Based on the tunnel deformation that was actually measured, the paper first back-calculates the rock mass strength by analytical approach. Then, the extent of in-situ stress condition in the area is determined by numerical modeling for the rock mass with no ground water in consideration. The ground water effect is then analyzed. We found that the effect of ground water with a static head <1.5 bar pressure may increase the deformation by up to a maximum of 30 %. Finally, we briefly discuss uncertainties related to the input parameter study and used methodologies.

  9. 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.

  10. Trial manufacture of a plunger to reduce finger exposure

    International Nuclear Information System (INIS)

    According to the results of to a survey conducted by the Japanese Society of Nuclear Medicine Technology in 1995, the mean monthly exposure dose to the trunk of nuclear medicine technicians was less than 0.2 mSv at more than 75% of the institutions, whereas the exposure dose to the fingers exceeded 0.5 mSv at 30% of the institutions. Many recent radiopharmaceuticals are being supplied as the syringe type, and while the syringe is surrounded by a tungsten or lead-glass shield, there is no shielding of the syringe needle or the plungers. The plastic plunger provides little shielding effect, and even when a tungsten plunger is used, calculating back from the leakage rate, the shielding effect for 99mTc is approximately 75%. We therefore trial-manufactured a plunger devised in such a manner as to considerably reduce exposure of the fingers and evaluated its shielding effect from leakage rate obtained with a dual-detector scintillation camera when the radionuclides 99mTc, 67Ga, 201Tl, and 123I were used. Its performance was satisfactory, with shielding effects (99mTc, 99%; 67Ga, 95%, 201Tl, 95%; 123I, 73%) about the same or better than back-calculated from the leakage rates. (author)

  11. 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.

  12. MQ-HNCO-TROSY for the measurement of scalar and residual dipolar couplings in larger proteins: application to a 557-residue IgFLNa16-21

    International Nuclear Information System (INIS)

    We describe a novel pulse sequence, MQ-HNCO-TROSY, for the measurement of scalar and residual dipolar couplings between amide proton and nitrogen in larger proteins. The experiment utilizes the whole 2TN polarization transfer delay for labeling of 15N chemical shift in a constant time manner, which efficiently doubles the attainable resolution in 15N dimension with respect to the conventional HNCO-TROSY experiment. In addition, the accordion principle is employed for measuring (J + D)NHs, and the multiplet components are selected with the generalized version of the TROSY scheme introduced by Nietlispach (J Biomol NMR 31:161-166, 2005). Therefore, cross peak overlap is diminished while the time period during which the 15N spin is susceptible to fast transverse relaxation associated with the anti-TROSY transition is minimized per attainable resolution unit. The proposed MQ-HNCO-TROSY scheme was employed for measuring RDCs in high molecular weight protein IgFLNa16-21 of 557 residues, resulting in 431 experimental RDCs. Correlations between experimental and back-calculated RDCs in individual domains gave relatively low Q-factors (0.19-0.39), indicative of sufficient accuracy that can be obtained with the proposed MQ-HNCO-TROSY experiment in high molecular weight proteins.

  13. Technetium diffusion in clay-based materials under oxic and anoxic conditions

    International Nuclear Information System (INIS)

    Diffusion coefficients were determined for Tc in compacted clay-based materials in both anoxic and oxic environments. The soils were saturated with a synthetic groundwater solution; the principle ions in solution were CA2+, Na+ and Cl-. Anoxic conditions were established by conducting the experiments in low-O2 glove box and by mixing 0.5 wt% powdered Fe with the soils. Under anoxic conditions, apparent diffusion coefficients, Da, were 2/s for Tc in compacted backfill material (a 1:3 mix by dry mass of Lake Agassiz clay and crushed granite aggregate). Distribution coefficients, Kd, for Tc on Lake Agassiz clay and backfill material in anoxic environments were back-calculated from Da values. Based on the Kd values, Tc strongly sorbs on Lake Agassiz clay and backfill under anoxic conditions. Effective diffusion coefficients De, for Tc of 10, 16 and 110 μm2/s were measured in oxic Avonlea bentonite, Lake Agassiz clay and illite-smectite, respectively, at a clay dry bulk density of ∼ 1.2 Mg/m3; the corresponding Da values were 55, 48 and 75 μm2/s. Since anoxic conditions are expected in a disposal vault excavated deep in granitic rock in the Canadian Shield, the results suggest the migration of Tc through the backfill will be relatively slow. (author) 23 refs., 9 tabs., 4 figs

  14. 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.

  15. Source area identification with observation from limited monitor sites for air pollution episodes in industrial parks

    Science.gov (United States)

    Huang, Zihan; Wang, Yuan; Yu, Qi; Ma, Weichun; Zhang, Yan; Chen, Limin

    2015-12-01

    Air pollution episodes of unknown origins are often detected by online equipment for air quality monitoring in industrial parks in China. The number of monitors available to provide observation data, as well as the source information, is often very limited. In such case, the identification of a potential source area is more practical than the precise back-calculation of the real source. The potential source area which can be deduced from the observation data from limited monitors was concerned in this paper. In order to do the source area identification, two inverse methods, a direct method and a statistical sampling method, were applied with a Gaussian puff model as the forward modeling method. The characteristic of the potential source area was illustrated by case studies. Both synthetic and real cases were presented. The distribution of the source locations and its variation with the other unknown source parameters were mainly focused in the case study. As a screening method, source area identification can be applied not only when the number of effective monitors is limited but also when an ideal number of monitors are available as long as the source information is almost uncertain.

  16. 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.

  17. Reworked old crust-derived shoshonitic magma: The Guarany pluton, Northeastern Brazil

    Science.gov (United States)

    Ferreira, Valderez P.; Sial, Alcides N.; Pimentel, Marcio M.; Armstrong, Richard; Guimarães, Ignez P.; da Silva Filho, Adejardo F.; de Lima, Mariucha Maria C.; da Silva, Thyego R.

    2015-09-01

    The 572 Ma Guarany stock consists of magmatic epidote-bearing hornblende monzodiorite to biotite granite that intruded Paleoproterozoic orthogneisses about 10 km inland from the coast in northeastern Brazil. Co-magmatic diorite enclaves and dikes are abundant throughout the pluton. The monzodiorite-granite pluton and diorite enclaves are shoshonitic and display continuous trends in variation diagrams. They display chemical and isotopic characteristics of crustal melts, such as enrichment in incompatible elements, high back-calculated initial 87Sr/86Sr ratios (avg. 0.71253), negative εNd (0.57Ga) values (avg. - 14.58), as well as high and variable (+ 9.1 to + 11.1‰VSMOW) δ18O (zircon) values. Correlations between O-isotope and whole-rock silica contents, as well as initial 87Sr/86Sr ratios with 1/Sr concentrations, suggest hybridization of a lower continental crustal melt with more felsic crustal rocks, concomitant with fractional crystallization. Amphibole chemistry and whole rock Zr, TiO2 and P2O5 contents suggest magma solidification at a pressure ~ 7 kbar and near liquidus temperature ~ 900 °C. The parental magma was likely formed by partial melting of old (tDM = 2.0 Ga) amphibolitic lower continental crustal rocks, in a post-collisional setting, probably triggered by underplating of mantle-derived mafic magma during the period of relaxation after collision.

  18. 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.

  19. 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.

  20. Evaluation of Management of Water Release for Painted Rocks Reservoir, Bitterroot River, Montana, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lere, Mark E. (Montana Department of Fish, Wildlife and Parks, Missoula, MT)

    1984-11-01

    Baseline fisheries and habitat data were gathered during 1983 and 1984 to evaluate the effectiveness of supplemental water releases from Painted Rocks Reservoir in improving the fisheries resource in the Bitterroot River. Discharge relationships among main stem gaging stations varied annually and seasonally. Flow relationships in the river were dependent upon rainfall events and the timing and duration of the irrigation season. Daily discharge monitored during the summers of 1983 and 1984 was greater than median values derived at the U.S.G.S. station near Darby. Supplemental water released from Painted Rocks Reservoir totaled 14,476 acre feet in 1983 and 13,958 acre feet in 1984. Approximately 63% of a 5.66 m{sup 3}/sec test release of supplemental water conducted during April, 1984 was lost to irrigation withdrawals and natural phenomena before passing Bell Crossing. A similar loss occurred during a 5.66 m{sup 3}/sec test release conducted in August, 1984. Daily maximum temperature monitored during 1984 in the Bitterroot River averaged 11.0, 12.5, 13.9 and 13.6 C at the Darby, Hamilton, Bell and McClay stations, respectively. Chemical parameters measured in the Bitterroot River were favorable to aquatic life. Population estimates conducted in the Fall, 1983 indicated densities of I+ and older rainbow trout (Salmo gairdneri) were significantly greater in a control section than in a dewatered section (p < 0.20). Numbers of I+ and older brown trout (Salmo trutta) were not significantly different between the control and dewatered sections (p > 0.20). Population and biomass estimates for trout in the control section were 631/km and 154.4 kg/km. In the dewatered section, population and biomass estimates for trout were 253/km and 122.8 kg/km. The growth increments of back-calculated length for rainbow trout averaged 75.6 mm in the control section and 66.9mm in the dewatered section. The growth increments of back-calculated length for brown trout averaged 79.5 mm in the

  1. 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.

  2. 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

  3. Anthropogenic CO2 estimates in the Southern Ocean: Storage partitioning in the different water masses

    Science.gov (United States)

    Pardo, Paula C.; Pérez, F. F.; Khatiwala, S.; Ríos, A. F.

    2014-01-01

    The role of the Southern Ocean (SO) remains a key issue in our understanding of the global carbon cycle and for predicting future climate change. A number of recent studies suggest that 30 to 40% of ocean uptake of anthropogenic carbon (CANT) occurs in the SO, accompanied by highly efficient transport of CANT by intermediate-depth waters out of that region. In contrast, storage of CANT in deep and bottom layers is still an open question. Significant discrepancies can be found between results from several indirect techniques and ocean models. Even though reference methodologies state that CANT concentrations in deep and bottom layers of the SO are negligible, recent results from tracer-based methods and ocean models as well as accurate measurements of 39Ar, CCl4 and CFCs along the continental slope and in the Antarctic deep and bottom waters contradict this conclusion. The role of the SO in the uptake, storage and transport of CANT has proved to be really important for the global ocean and there is a need for agreement between the different techniques. A CO2-data-based ("back-calculation") method, the CT0 method, was developed with the aim of obtaining more accurate CANT concentration and inventory estimates in the SO region (south of 45°S). Data from the GLODAP (Global Ocean Data Analysis Project) and CARINA databases were used. The CT0 method tries to reduce at least two of the main caveats attributed to the back-calculation methods: the need for a better definition of water mass mixing and, most importantly, the unsteady state of the air-sea CO2 disequilibrium (ΔCdis) term. Water mass mixing was computed on the basis of results from an extended Optimum Multi-Parametric (eOMP) analysis applied to the main water masses of the SO. Recently published parameterizations were used to obtain more reliable values of ΔCdis and also of preformed alkalinity. The variability of the ΔCdis term (δCdis) was approximated using results from an ocean carbon cycle model

  4. Towards a numerical run-out model for quick-clay slides

    Science.gov (United States)

    Issler, Dieter; L'Heureux, Jean-Sébastien; Cepeda, José M.; Luna, Byron Quan; Gebreslassie, Tesfahunegn A.

    2015-04-01

    Highly sensitive glacio-marine clays occur in many relatively low-lying areas near the coasts of eastern Canada, Scandinavia and northern Russia. If the load exceeds the yield stress of these clays, they quickly liquefy, with a reduction of the yield strength and the viscosity by several orders of magnitude. Leaching, fluvial erosion, earthquakes and man-made overloads, by themselves or combined, are the most frequent triggers of quick-clay slides, which are hard to predict and can attain catastrophic dimensions. The present contribution reports on two preparatory studies that were conducted with a view to creating a run-out model tailored to the characteristics of quick-clay slides. One study analyzed the connections between the morphological and geotechnical properties of more than 30 well-documented Norwegian quick-clay slides and their run-out behavior. The laboratory experiments by Locat and Demers (1988) suggest that the behavior of quick clays can be reasonably described by universal relations involving the liquidity index, plastic index, remolding energy, salinity and sensitivity. However, these tests should be repeated with Norwegian clays and analyzed in terms of a (shear-thinning) Herschel-Bulkley fluid rather than a Bingham fluid because the shear stress appears to grow in a sub-linear fashion with the shear rate. Further study is required to understand the discrepancy between the material parameters obtained in laboratory tests of material from observed slides and in back-calculations of the same slides with the simple model by Edgers & Karlsrud (1982). The second study assessed the capability of existing numerical flow models to capture the most important aspects of quick-clay slides by back-calculating three different, well documented events in Norway: Rissa (1978), Finneidfjord (1996) and Byneset (2012). The numerical codes were (i) BING, a quasi-two-dimensional visco-plastic model, (ii) DAN3D (2009 version), and (iii) MassMov2D. The latter two are

  5. 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

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

    Science.gov (United States)

    Hoffmann, Friederike; Røy, Hans; Bayer, Kristina; Hentschel, Ute; Pfannkuchen, Martin; Brümmer, Franz; de Beer, Dirk

    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, which allows total oxygen consumption rates of 6-12 μmol cm(-3) sponge day(-1). Sponges of different sizes had similar diffusional uptake rates, which is explained by their similar surface/volume ratios. In pumping sponges, oxygen consumption rates were between 22 and 37 μmol cm(-3) sponge day(-1), and the entire tissue was oxygenated. Combining different approaches of direct oxygen measurement in living sponges with a dynamic model, we can show that tissue anoxia is a direct function of the pumping behavior. The sponge-microbe system of A. aerophoba thus has the possibility to switch actively between aerobic and anaerobic metabolism by stopping the water flow for more than 15 min. These periods of anoxia will greatly influence physiological variety and activity of the sponge microbes. Detailed knowledge about the varying chemical microenvironments in sponges will help to develop protocols to cultivate sponge-associated microbial lineages and improve our understanding of the sponge-microbe-system. PMID:24391232

  7. 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

  8. (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

  9. 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.

  10. Determination of phosphodiesterase type V inhibitors in wastewater by direct injection followed by liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Causanilles, Ana; Emke, Erik; de Voogt, Pim

    2016-09-15

    A simple, fast and reliable analytical method for the determination of phosphodiesterase type V inhibitors in wastewater was developed and validated. The method was based on direct injection followed by liquid chromatography coupled to tandem mass spectrometry with triple quadrupole as mass analyzer. Transformation products and analogues were included in the target list besides the three active pharmaceutical ingredients (sildenafil, vardenafil and tadalafil). The method performance was thoroughly investigated, including the analyte stability in wastewater and matrix effect. All target compounds presented linear fits between their LOD and 500ng/L. The quantification limits ranged from 1.6 to 30ng/L for all compounds except for n-octylnortadalafil (LOQ: 100ng/L); precision calculated as intraday repeatability was lower than 30%; accuracy calculated as procedural recovery ranged successfully between 85 and 105% in all cases. The method was applied to samples collected during three week-long monitoring campaigns performed in 2013, 2014 and 2015 in three Dutch cities. Only sildenafil and its two metabolites, desmethyl- and desethylsildenafil, were present with normalized loads ranging from LOQ to 8.3, 11.8 and 21.6mg/day/1000 inh, respectively. Two additional week-long sets of samples were collected in Amsterdam at the time that a festival event took place, bringing around 350,000 visitors to the city. The difference in drug usage patterns was statistically studied: "weekday" versus "weekend", "normal" versus "atypical" week; and results discussed. The metabolite to parent drug concentration ratio evolution during consecutive years was discussed, leading to several possible explanations that should be further investigated. Finally, wastewater-based epidemiology approach was applied to back-calculate sildenafil consumption. PMID:27161135

  11. 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.

  12. 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.

  13. Mechanical response of jointed granite during shaft sinking at the Canadian Underground Research Laboratory

    International Nuclear Information System (INIS)

    As part of the geoscience research within the Canadian Nuclear Fuel Waste Management Program, Atomic Energy of Canada Limited (AECL) is constructing an underground research laboratory (URL) in a previously undisturbed portion of a granitic intrusive, the Lac du Bonnet batholith, approximately 100 km northeast of Winnipeg, Manitoba. The overall geotechnical objectives of the URL are to assess and improve our ability to interpret and predict the geological, geophysical, geochemical, geomechanical and hydrogeological conditions of large bodies of plutonic rock, as well as to assess the accuracy of mathematical models used to predict the near-field mechanical and hydrogeological responses of the rock mass to excavation and thermal loading. Construction will be completed in July, 1986. Large-scale testing will commence soon afterwards and will last until the facility is decommissioned in the year 2000. A rectangular access shaft, 255 m deep x 2.8 m x 4.8 m, was sunk during the period May 1984 to March 1985. Rock displacements and stress changes were monitored as the excavation face (bottom) of the shaft advanced. The major objectives of this monitoring were (a) to evaluate and improve the ability of numerical models in predicting the mechanical response of the rock mass, (b) to back-calculate the rock-mass deformation modulus as a function of depth, (c) to assess the influence of natural fractures on the mechanical response of the granitic rock mass, and (d) to evaluate the quality of the geomechanical instrumentation, to determine instrumentation needs for future field experiments. Analysis of the data from this monitoring will aid the design and modelling of further experiments in the URL. In this paper, the rock displacements measured by an array of extensometers at 15 m below ground surface are presented and compared with predictions by a three-dimensional elastic continuum finite-element model

  14. 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

  15. 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.

  16. Density of asphalt paving mixtures: Measurements, variations, and influencing factors

    International Nuclear Information System (INIS)

    The first part describes the results of a research study to determine the effectiveness of the Troxler Model 4640 Thin Lift Nuclear Density Gauge. The densities obtained from cores and the nuclear density gauge from seven construction projects were compared. A linear regression technique was used to investigate how well the core densities could be predicted from nuclear densities. Correlation coefficients were determined to indicate the degree of correlation between the core and nuclear densities. Using a statistical analysis technique, the range of differences between core and nuclear measurements was established for specified confidence levels for each project. Analysis of the data indicated that the accuracy of this gauge is highly material dependent. While acceptable results were obtained with limestone mixtures, the gauge did not perform satisfactorily with mixtures containing siliceous aggregate. The data presented in this paper indicate that the gauge could be used as a quality control tool provided that a calibration is developed for each project. The maximum theoretical specific gravities of asphalt-aggregate paving mixtures obtained from different methods were compared. The study included experimental work and analysis of the resulting data. The agreement between results obtained from the Texas C-14 method and the Rice method were excellent. Results obtained by backcalculating theoretical maximum densities from a single Rice test were also found to be satisfactory. Theoretical approach based on bulk specific gravity of aggregate is not recommended because of yielding significantly low theoretical maximum specific gravities and high relative densities. The last two parts summarize density levels and corresponding variations obtained from fifty-seven construction projects throughout the state of Texas

  17. Trends of Amphetamine Type Stimulants DTR Mass Load in Poznan Based on Wastewater Analysis.

    Directory of Open Access Journals (Sweden)

    Piotr Nowicki

    2014-05-01

    Full Text Available The aim of this study was to determine the monthly DTR mass load of amphetamine-type compounds in Poland as well as an investigation of cyclical behaviour by using time series analysis and especially trends analysis.Amphetamine, methamphetamine and MDMA (ecstasy were detected in wastewater samples collected from the main Wastewater Treatment Plant in the city of Poznan using liquid chromatography / tandem mass spectrometry (LC-MS-MS. Back-calculations used in the sewage epidemiology approach were applied to estimate the DTR mass load level of the drugs analyzed. Trends analysis was performed by fitting the data to a simple linear regression and then by using smoothing by means of a moving average (Mat lab 2013a. Trend analysis displays a steady tendency of increase or decrease throughout time series. When we plot the observation against time, we may notice that a straight line can describe the increase or decrease in the series as time goes on. Simple linear regression and method of last squares to estimate parameters of a straight-line model were used. Additionally, a lagged plot (autocorrelation plot was used to investigate an appearance of correlation between amphetamines throughout time.Trends analysis showed the slight increase in consumption of amphetamine and decreasing trend in case of ecstasy and methamphetamine within the investigated period. There is also visible, strong correlation between ecstasy and methamphetamine consumption which cannot be stated in case of amphetamine.Trends analysis is a very useful tool to analyse the increasing or decreasing tendency in consumption of illicit drugs based on the DTR mass load data.

  18. Estimating Crop Coefficients Using Remote Sensing-Based Vegetation Index

    Directory of Open Access Journals (Sweden)

    Kenneth Hubbard

    2013-03-01

    Full Text Available Crop coefficient (Kc-based estimation of crop evapotranspiration is one of the most commonly used methods for irrigation water management. However, uncertainties of the generalized dual crop coefficient (Kc method of the Food and Agricultural Organization of the United Nations Irrigation and Drainage Paper No. 56 can contribute to crop evapotranspiration estimates that are substantially different from actual crop evapotranspiration. Similarities between the crop coefficient curve and a satellite-derived vegetation index showed potential for modeling a crop coefficient as a function of the vegetation index. Therefore, the possibility of directly estimating the crop coefficient from satellite reflectance of a crop was investigated. The Kc data used in developing the relationship with NDVI were derived from back-calculations of the FAO-56 dual crop coefficients procedure using field data obtained during 2007 from representative US cropping systems in the High Plains from AmeriFlux sites. A simple linear regression model ( is developed to establish a general relationship between a normalized difference vegetation index (NDVI from a moderate resolution satellite data (MODIS and the crop coefficient (Kc calculated from the flux data measured for different crops and cropping practices using AmeriFlux towers. There was a strong linear correlation between the NDVI-estimated Kc and the measured Kc with an r2 of 0.91 and 0.90, while the root-mean-square error (RMSE for Kc in 2006 and 2007 were 0.16 and 0.19, respectively. The procedure for quantifying crop coefficients from NDVI data presented in this paper should be useful in other regions of the globe to understand regional irrigation water consumption.

  19. Quantitative interpretation of tracks for determination of body mass.

    Science.gov (United States)

    Schanz, Tom; Lins, Yvonne; Viefhaus, Hanna; Barciaga, Thomas; Läbe, Sashima; Preuschoft, Holger; Witzel, Ulrich; Sander, P Martin

    2013-01-01

    To better understand the biology of extinct animals, experimentation with extant animals and innovative numerical approaches have grown in recent years. This research project uses principles of soil mechanics and a neoichnological field experiment with an African elephant to derive a novel concept for calculating the mass (i.e., the weight) of an animal from its footprints. We used the elephant's footprint geometry (i.e., vertical displacements, diameter) in combination with soil mechanical analyses (i.e., soil classification, soil parameter determination in the laboratory, Finite Element Analysis (FEA) and gait analysis) for the back analysis of the elephant's weight from a single footprint. In doing so we validated the first component of a methodology for calculating the weight of extinct dinosaurs. The field experiment was conducted under known boundary conditions at the Zoological Gardens Wuppertal with a female African elephant. The weight of the elephant was measured and the walking area was prepared with sediment in advance. Then the elephant was walked across the test area, leaving a trackway behind. Footprint geometry was obtained by laser scanning. To estimate the dynamic component involved in footprint formation, the velocity the foot reaches when touching the subsoil was determined by the Digital Image Correlation (DIC) technique. Soil parameters were identified by performing experiments on the soil in the laboratory. FEA was then used for the backcalculation of the elephant's weight. With this study, we demonstrate the adaptability of using footprint geometry in combination with theoretical considerations of loading of the subsoil during a walk and soil mechanical methods for prediction of trackmakers weight. PMID:24204890

  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

    International Nuclear Information System (INIS)

    Water is one of the most difficult chemicals in which to measure 180 content. The classical method consisted of equilibrating a sample of water with a known amount of CO2, followed by the determination of the 180 content of the CO27 and back-calculating via the known equilibrium constant for this reaction. Another method is the pyrolysis of an H20 sample with guanidine hydrochloride. The CO2 produced from pyrolysis contains oxygen with the same 180 content as that of the original H20 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 [180] H20 was placed in a PCl5 reaction vessel. The phosphoric acid resulting from complete hydrolysis of the PCl5 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 N2, and diluting with CHCl3. The electron impact mass spectrum of trimethyl phosphate observed was consistent with that reported by Bafus et al. Basing the final calculated 180 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 PCl5 introduces four oxygens from water into the H3P04, a statistical distribtuion of the five isotopomers of H3P04 should be obtained, assuming no isotope effects in the PCl5 hydrolysis. 2 tables

  1. What experimental factors influence the accuracy of retention projections in gas chromatography-mass spectrometry?

    Science.gov (United States)

    Wilson, Michael B; Barnes, Brian B; Boswell, Paul G

    2014-12-19

    Programmed-temperature gas chromatographic (GC) retention information is difficult to share because it depends on so many experimental factors that vary among laboratories. Though linear retention indexing cannot properly account for experimental differences, retention times can be accurately calculated, or "projected", from shared isothermal retention vs. temperature (T) relationships, but only if the temperature program and hold-up time vs. T profile produced by a GC is known with great precision. The effort required to measure these profiles were previously impractical, but we recently showed that they can be easily back-calculated from the programmed-temperature retention times of a set of 25 n-alkanes using open-source software at www.retentionprediction.org/gc. In a multi-lab study, the approach was shown to account for both intentional and unintentional differences in the temperature programs, flow rates, and inlet pressures produced by the GCs. Here, we tested 16 other experimental factors and found that only 5 could reduce accuracy in retention projections: injection history, exposure to very high levels of oxygen at high temperature, a very low transfer line temperature, an overloaded column, and a very short column (≤15m). We find that the retention projection methodology acts as a hybrid of conventional retention projection and retention indexing, drawing on the advantages of both; it properly accounts for a wide range of experimental conditions while accommodating the effects of experimental factors not properly taken into account in the calculations. Finally, we developed a four-step protocol to efficiently troubleshoot a GC system after it is found to be yielding inaccurate retention projections. PMID:25482038

  2. 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

  3. Kootenai River white sturgeon investigations. Chapter 1: Kootenai River white sturgeon spawning and recruitment evaluation; Annual report, January 1--December 31, 1996

    International Nuclear Information System (INIS)

    Test flows for Kootenai River white sturgeon Acipenser transmontanus spawning, scheduled for June 1996, were postponed until July. However, an estimated 126% snow pack and unusually heavy precipitation created conditions for sturgeon spawning that were similar to those occurring before construction of Libby Dam. Discharge in the Kootenai River at Bonners Ferry rose to nearly 1,204 m3/s (42,500 cfs) during May and water temperature ranged from 5.8 C to 8.4 C (42 F to 47 F). Migration of adult white sturgeon into spawning areas occurred in late May during a rising hydrograph. Discharge and water temperature were rising and had reached approximately 1,077 m3/s (38,000 cfs) and 8 C (46 F). Discharge at Bonners Ferry peaked at about 1,397 m3/s (49,300 cfs) on June 5. A total of 348 eggs (and one egg shell) were collected with 106,787 h of mat effort during the flow events. The first white sturgeon eggs were collected on June 8 and continued through June 30. Staging of eggs and back-calculating to spawning dates indicated there were at least 18 spawning episodes between June 6 and June 25. Discharge on June 6 was 1,196 m3/s (42,200 cfs) and decreased steadily to 850 m3/s (30,000 cfs) by June 26. Although sturgeon spawned in the same reach of river that they had during 1994 and 1995, the majority of eggs were found significantly (P = 0.0001) farther upstream than 1994 and 1995 and this in turn may be related to elevation of Kootenay Lake

  4. 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.

  5. 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

  6. Time variations in the transmissibility of pandemic influenza in Prussia, Germany, from 1918–19

    Directory of Open Access Journals (Sweden)

    Nishiura Hiroshi

    2007-06-01

    Full Text Available Abstract Background Time variations in transmission potential have rarely been examined with regard to pandemic influenza. This paper reanalyzes the temporal distribution of pandemic influenza in Prussia, Germany, from 1918–19 using the daily numbers of deaths, which totaled 8911 from 29 September 1918 to 1 February 1919, and the distribution of the time delay from onset to death in order to estimate the effective reproduction number, Rt, defined as the actual average number of secondary cases per primary case at a given time. Results A discrete-time branching process was applied to back-calculated incidence data, assuming three different serial intervals (i.e. 1, 3 and 5 days. The estimated reproduction numbers exhibited a clear association between the estimates and choice of serial interval; i.e. the longer the assumed serial interval, the higher the reproduction number. Moreover, the estimated reproduction numbers did not decline monotonically with time, indicating that the patterns of secondary transmission varied with time. These tendencies are consistent with the differences in estimates of the reproduction number of pandemic influenza in recent studies; high estimates probably originate from a long serial interval and a model assumption about transmission rate that takes no account of time variation and is applied to the entire epidemic curve. Conclusion The present findings suggest that in order to offer robust assessments it is critically important to clarify in detail the natural history of a disease (e.g. including the serial interval as well as heterogeneous patterns of transmission. In addition, given that human contact behavior probably influences transmissibility, individual countermeasures (e.g. household quarantine and mask-wearing need to be explored to construct effective non-pharmaceutical interventions.

  7. Evaluation of drugs of abuse use and trends in a prison through wastewater analysis.

    Science.gov (United States)

    Postigo, Cristina; de Alda, Miren López; Barceló, Damià

    2011-01-01

    Illicit drugs and metabolites have been recognized recently as a group of emerging contaminants of concern, as a consequence of their high volumes of use and production. Drug residue levels in the aquatic environment have also been pointed out as good indicators of illicit drug abuse. The present work assesses for the first time drug abuse in a penal complex from the levels of different drug residues measured in the prison sewage waters and evaluates the suitability of this approach to track and control illicit drug usage in such facilities. The presence of various drugs of abuse and metabolites in sewage waters from a penal complex was determined by an analytical method based on on-line solid phase extraction-liquid chromatography-tandem mass spectrometry. Levels of consumption indicators measured in this water were used to back-calculate drugs usage in the penal complex. Daily use was observed for methadone (average of 156 doses/day/1000 inh), alprazolam (129 doses/day/1000 inh), ephedrine (46 doses/day/1000 inh), cannabis (33 doses/day/1000 inh.) and cocaine (3 doses/day/1000 inh). Sporadic consumption was observed for heroin, amphetamine, methamphetamine, and ecstasy. In spite of the fact that this and other sewage epidemiological approaches described may suffer from bias that still need to be investigated and refined, it provides near "real-time" information on collective drug use in an anonymous way and constitutes a very useful, economic and fast tool to evaluate the efficiency of measures adopted to control and track drug abuse in this type of facilities (or any other provided that has a STP associated or an accessible collector system). PMID:20655111

  8. 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

  9. 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.

  10. Developpement d'un catalogue de conception des chaussee pour les pays sub-sahariens

    Science.gov (United States)

    Koubikana Pambou, Claude Hugo

    Pavement surface evaluation in Sub-Saharan Africa (SSA) reveals severe, premature, and costly damages that require extensive maintenance. This is due to the limitations of tools used for pavement structural design as well as and the lack of the available calibration for the materials used. It is necessary to search for solutions for these failures and: * feed the discussion on durable roads for SSA area to meet the expectations of the trans- African highway projects of the new partnership for Africa (NEPAD); * provide simple and effective tools for pavement design and promote low cost for maintenance of road infrastructures; * provide users with functional and safety and durable road system. This catalogue, object and result of this work, was developed through a new tool for structural design (OCS-Chaussee), computed using Microsoft Excel worksheet. It uses iteration through empirical mechanics (ME) methods, applied to multilayer linear analysis using Odemark - Boussinesq method as a theoretical and conceptual basis for design pavement. The verification of obtained results was done with viscoelasticity assumption according Quijano's data (2010) and the pavement analysis software WINJULEA developed by US Army Corps of Engineers (USACE) and with the backcalculation's data from Varik and al. (2002) and local's data from South-African. The lifetime of each proposed roadway was estimated by using Asphalt Institute's transfer function and the Miner's law. It's hope that thoughtful use of this catalogue and the OCS- Chaussee will help advance reasonable road engineering solutions approaches, and training and make profitable budgets allocated to the construction and to road rehabilitation in Sub-Saharan Africa.

  11. 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

  12. 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

  13. 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

  14. 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)

  15. 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.

  16. Hydrologic predictions on ungauged catchments using deterministic distributed modelling system

    Science.gov (United States)

    Tachecí, Pavel; Kimlová, Martina

    2010-05-01

    simulation. Back-calculation of initial conditions using regular observation network data is applied to minimize errors of water balance. Scaled values of simulated deficit of water content in unsaturated zone, aggregated over user-defined areas, were chosen as flash-flood danger indicator. User - defined templates for presentation of results are available. The advantage of this approach sustains in a fact, that it uses three different types of input data. Further on, it may give results for user-defined areas, which are not necessarily connected to on-line flow gauging station profiles. This means, that it is capable to give flash-flood danger maps also for upper catchments and small tributaries, which are not included in the network of main warning profiles.

  17. 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

  18. 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)

  19. Intraocular Lens Power Calculation after Corneal Refractive Surgery

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2012-01-01

    Full Text Available Purpose: To report refractive outcomes following phacoemulsification (PE and posterior chamber intraocular lens (PCIOL implantation in eyes with previous corneal refractive surgery. Methods: In this retrospective comparative study, 18 consecutive eyes of 14 patients with previous keratorefractive surgery for myopia including photorefractive keratectomy (PRK, 6 eyes; 33.3% and laser in situ keratomileusis (LASIK, 12 eyes; 66.7% underwent PE+PCIOL. Computerized corneal topography was employed to determine the flattest keratometric reading within the 3-mm central zone. This value was inserted into the Sanders-Retzlaff-Kraff/T (SRK/T formula to calculate IOL power. IOL power selected for implantation was 1 D greater than the calculated value described above. Results: Mean age and follow-up period were 54.1±11.5 years and 29.9±26.3 months, respectively. Mean implanted lens power was 18.56±3.86 D which was not significantly different from mean back-calculated IOL power for target refraction (19.04±4.16 D (P=0.28. There was no significant difference between mean target refraction (-0.94±0.52 D and achieved postoperative spherical equivalent refractive error (-0.62±1.06 at final follow-up (P=0.28. The achieved spherical equivalent refractive error was within ±0.50 D of intended refraction in 8 (44.4% eyes, within ±1.0 D in 11 (61.1% eyes, and within ±2.0 D in 16 (88.9% eyes. In a subgroup of patients (5 eyes with complete pre-refractive surgery data, the difference between post-refractive surgery keratometry method and all other methods (P=0.02 and between the current method and the Feiz-Mannis method (P=0.01 was statistically significant. Conclusion: The method suggested herein is simple and independent of pre-refractive surgery data with results comparable to other commonly used methods.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. Stardust Under a Microscope - 3D maps of Wild 2/81P Cometary Samples in Aerogel

    Science.gov (United States)

    White, Amanda J.; Ebel, Denton

    2016-01-01

    The NASA Stardust mission to comet Wild 2 returned to Earth in 2006 with cometary and interstellar material captured in aerogel. Cometary particles impacted an aerogel collector at a relative velocity of 6.1 km/s, creating three-dimensional (3D) impact tracks of melted and crushed aerogel, void space, and fragmented cometary material. Each track represents the history of a unique hypervelocity capture event. The nature of each impact, including the original state of the impactor, is recorded in track morphology and material distribution. Using a combination of 3D morphological data, chemical data, and microphysical models, it is possible to reconstruct track formation events and a model of the original impactor.The focus of this work is to fully characterize whole tracks both morphologically and chemically using solely non-destructive methods. To achieve this, we combine high-resolution laser scanning confocal microscope (LSCM) 3D imaging with synchrotron X-ray fluorescence (SXRF) chemical mapping. We are also beginning to incorporate Raman spectroscopy to perform mineral phase analysis of fine track wall material. Using a Zeiss LSM 710 LSCM located in the American Museum of Natural History, we have imaged the morphology of over a dozen, whole Stardust tracks at high resolution (<80 nm/pixel in XY). We obtain the distribution of fine material along the track walls both quickly and without disturbing the sample. Complementary chemical data is acquired using the GSECARS X-ray microbe on beamline 13-IDE at the Advance Photon Source (APS) of Argonne National Laboratory. X-ray fluorescence maps of each track were collected with 100ms/pixel dwell time at a resolution of 1 or 2 micron/pixel. Many tracks were tilted and mapped a second time for stereo measurements.A thorough understanding of how cometary material and aerogel is distributed along tracks is required to understand the events which occurred after impact and to back-calculate properties of the original impactor

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. UAV-based Natural Hazard Management in High-Alpine Terrain - Case Studies from Austria

    Science.gov (United States)

    Sotier, Bernadette; Adams, Marc; Lechner, Veronika

    2015-04-01

    images: In the upper part of the steep channel there was no GPS-signal available, because of the high surrounding rock faces, the landing area consisted of coarse gravel. Therefore, only a manual flight with a high risk of damage was possible. With the calculated RPAS-based digital surface model, created from the 600 aerial images, a chronologically resolved back-calculation of the last big debris-flow event could be performed. In a third case study, aerial images from RPAS were used for a similar investigation in Virgen, Eastern Tyrol (Austria). A debris flow in the Firschnitzbach catchment caused severe damages to the village of Virgen in August 2012. An RPAS-flight was performed, in order to refine the estimated displaced debris mass for assessment purposes. The upper catchment of the Firschnitzbach is situated above the timberline and covers an area of 6.5 ha at a height difference of 1000 m. Therefore, three separate flights were necessary to achieve a sufficient image overlap. The central part of the Firschnitzbach consists of a steep and partly dense forested canyon / gorge, so there was no flight possible for this section up to now. The evaluation of the surface model from the images showed, that only half of the estimated debris mass came from the upper part of the catchment.

  13. 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.

  14. TRUE Block Scale Continuation Project. Final Report

    International Nuclear Information System (INIS)

    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 κ parameter, are one order of magnitude higher than for the background fracture flow path. This finding is consistent with the developed

  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. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. Age and growth of the scalloped hammerhead shark, Sphyrna lewini (Griffith & Smith, 1834 from the Southern coast of Sinaloa, México Edad y crecimiento del tiburón martillo, Sphyrna lewini (Griffith & Smith, 1834 de la costa sur de Sinaloa, México

    Directory of Open Access Journals (Sweden)

    Vicente Anislado-Tolentino

    2008-03-01

    Full Text Available Age and growth for the scalloped hammerhead shark (Sphyrna lewini were determined from opaque bands (OBs on postcephalic vertebrae from 109 organisms (44 females, 52 cm to 276 cm total length (TL and 65 males, 47 cm to 245 cm TL obtained bimonthly from commercial fisheries off the southern coast of Sinaloa state (23°45'25"N and 106°05'15"W to 21°52'N and 105°54'W from January 2003 to February 2005. The Bowker test of symmetry and the Index of Average Percent Error, suggest that this ageing method represents an unbiased and precise age assessment. Results show that immediately after birth (in summer, the first OB was formed and in the next winter showed the second OB. Later it was observed that two OBs were formed each year, one during summer and the other during winter, influenced by the sea surface temperature (SST. Based on the comparison of five back-calculation methods, the best methods were Fraser-Lee. The parameters of the von Bertalanffy growth function were, for females: L∞ = 376 cm, K = 0.1 year-1, t0 = -1.16 years, b = 3 and W∞ = 222 kg; for males: L∞= 364 cm, K = 0.123 year-1, t0 = 1.18 years, b = 3 and W∞ = 193 kg. The standard index growth (Φ' was 4.2 (s = 0.1. According to these results the largest sharks observed, a female of 280 cm TL would be 12.5 years old and a male of 281 cm TL would be 11 years old.Se estimó la edad y el crecimiento del tiburón martillo (Sphyrna lewini a través de bandas opacas (BOs en las vértebras postcefálicas de 109 organismos (44 hembras, 52 cm a 276 cm de longitud total (LT y 65 machos, 47 cm a 245 cm LT colectados bimensualmente en la pesca comercial en la costa sur del estado de Sinaloa (23°45'25"N y 106°05'15"W a 21°52'N y 105°54'W de enero 2003 a febrero 2005. La prueba de simetría de Bowker y el índice del error promedio porcentual sugieren que los métodos usados fueron los correctos para determinar la edad. Los resultados muestran que inmediatamente después de nacer

  3. Effects of Experimental High Flow Releases and Increased Fluctuations in Flow from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lee's Ferry Reach of the Colorado River

    Science.gov (United States)

    Korman, Josh

    2010-05-01

    The abundance of adult fish populations is controlled by the growth and survival rates of early life stages. Evaluating the effects of flow regimes on early life stages is therefore critical to determine how these regimes affect the abundance of adult populations. Experimental high flow releases from Glen Canyon Dam, primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River in Grand Canyon, AZ, have been conducted in 1996, 2004, and 2008. These flows potentially affect the Lee's Ferry reach rainbow trout population, located immediately downstream of the dam, which supports a highly valued fishery and likely influences the abundance of rainbow trout in Grand Canyon. Due to concerns about negative effects of high trout abundance on endangered native fish, hourly variation in flow from Glen Canyon Dam was experimentally increased between 2003 and 2005 to reduce trout abundance. This study reports on the effects of experimental high flow releases and fluctuating flows on early life stages of rainbow trout in the Lee's Ferry reach based on monthly sampling of redds (egg nests) and the abundance and growth of age-0 trout between 2003 and 2009. Data on spawn timing, spawning elevations, and intergravel temperatures were integrated in a model to estimate the magnitude and seasonal trend in incubation mortality resulting from redd dewatering due to fluctuations in flow. Experimental fluctuations from January through March promoted spawning at higher elevations where the duration of dewatering was longer and intergravel temperatures exceeded lethal thresholds. Flow-dependent incubation mortality rates were 24% (2003) and 50% (2004) in years with higher flow fluctuations, compared to 5-11% under normal operations (2006-2009). Spatial and temporal predictions of mortality were consistent with direct observations of egg mortality determined from the excavation of 125 redds. The amount of variation in backcalculated hatch

  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. 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

  6. 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.