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...

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

    Institute of Scientific and Technical Information of China (English)

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


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

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

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


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

  4. Evaluation of three aging techniques and back-calculated growth for introduced Blue Catfish from Lake Oconee, Georgia (United States)

    Homer, Michael D.; Peterson, James T.; Jennings, Cecil A.


    Back-calculation of length-at-age from otoliths and spines is a common technique employed in fisheries biology, but few studies have compared the precision of data collected with this method for catfish populations. We compared precision of back-calculated lengths-at-age for an introducedIctalurus furcatus (Blue Catfish) population among 3 commonly used cross-sectioning techniques. We used gillnets to collect Blue Catfish (n = 153) from Lake Oconee, GA. We estimated ages from a basal recess, articulating process, and otolith cross-section from each fish. We employed the Frasier-Lee method to back-calculate length-at-age for each fish, and compared the precision of back-calculated lengths among techniques using hierarchical linear models. Precision in age assignments was highest for otoliths (83.5%) and lowest for basal recesses (71.4%). Back-calculated lengths were variable among fish ages 1–3 for the techniques compared; otoliths and basal recesses yielded variable lengths at age 8. We concluded that otoliths and articulating processes are adequate for age estimation of Blue Catfish.

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

    Directory of Open Access Journals (Sweden)

    Ben Lopman

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

  6. Backcalculation of the disease-age specific frequency of sec-ondary transmission of primary pneumonic plague

    Institute of Scientific and Technical Information of China (English)

    Hiroshi Nishiura


    The purpose of the paper was to assess the frequency of secondary transmissions of primary pneumonic plague relative to the onset of fever.A simple backcalculation method was employed to estimate the frequency of sec-ondary transmissions relative to disease-age.A likelihood-based procedure was taken using observed distribu-tions of the serial interval (n = 177)and incubation period (n = 126).Furthermore,an extended model was developed to account for the survival probability of cases.The simple backcalculation suggested that 31. 0% (95% confidence intervals (CI):11.6,50.4)and 28.0 % (95% CI:10.2,45.8)of the total number of secondary transmissions had occurred at second and third days of the disease,respectively,and more than four-fifths of the secondary transmission occurred before the end of third day of disease.The survivorship-ad-justed frequency of secondary transmissions was obtained,demonstrating that the infectiousness in later stages of illness was not insignificant and indicates that the obtained frequencies were likely biased on underlying fac-tors including isolation measures.In conclusion,the simple exercise suggests a need to implement countermeas-ures during pre-clinical stage or immediately after onset.Further information is needed to elucidate the finer details of the disease-age specific infectiousness.

  7. Illicit and pharmaceutical drug consumption estimated via wastewater analysis. Part B: Placing back-calculations in a formal statistical framework (United States)

    Jones, Hayley E.; Hickman, Matthew; Kasprzyk-Hordern, Barbara; Welton, Nicky J.; Baker, David R.; Ades, A.E.


    Concentrations of metabolites of illicit drugs in sewage water can be measured with great accuracy and precision, thanks to the development of sensitive and robust analytical methods. Based on assumptions about factors including the excretion profile of the parent drug, routes of administration and the number of individuals using the wastewater system, the level of consumption of a drug can be estimated from such measured concentrations. When presenting results from these ‘back-calculations’, the multiple sources of uncertainty are often discussed, but are not usually explicitly taken into account in the estimation process. In this paper we demonstrate how these calculations can be placed in a more formal statistical framework by assuming a distribution for each parameter involved, based on a review of the evidence underpinning it. Using a Monte Carlo simulations approach, it is then straightforward to propagate uncertainty in each parameter through the back-calculations, producing a distribution for instead of a single estimate of daily or average consumption. This can be summarised for example by a median and credible interval. To demonstrate this approach, we estimate cocaine consumption in a large urban UK population, using measured concentrations of two of its metabolites, benzoylecgonine and norbenzoylecgonine. We also demonstrate a more sophisticated analysis, implemented within a Bayesian statistical framework using Markov chain Monte Carlo simulation. Our model allows the two metabolites to simultaneously inform estimates of daily cocaine consumption and explicitly allows for variability between days. After accounting for this variability, the resulting credible interval for average daily consumption is appropriately wider, representing additional uncertainty. We discuss possibilities for extensions to the model, and whether analysis of wastewater samples has potential to contribute to a prevalence model for illicit drug use. PMID:24636801

  8. Occurrence and fate of pharmaceutically active compounds in the largest municipal wastewater treatment plant in Southwest China: mass balance analysis and consumption back-calculated model. (United States)

    Yan, Qing; Gao, Xu; Huang, Lei; Gan, Xiu-Mei; Zhang, Yi-Xin; Chen, You-Peng; Peng, Xu-Ya; Guo, Jin-Song


    The occurrence and fate of twenty-one pharmaceutically active compounds (PhACs) were investigated in different steps of the largest wastewater treatment plant (WWTP) in Southwest China. Concentrations of these PhACs were determined in both wastewater and sludge phases by a high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Results showed that 21 target PhACs were present in wastewater and 18 in sludge. The calculated total mass load of PhACs per capita to the influent, the receiving water and sludge were 4.95mgd(-1)person(-1), 889.94μgd(-1)person(-1) and 78.57μgd(-1)person(-1), respectively. The overall removal efficiency of the individual PhACs ranged from "negative removal" to almost complete removal. Mass balance analysis revealed that biodegradation is believed to be the predominant removal mechanism, and sorption onto sludge was a relevant removal pathway for quinolone antibiotics, azithromycin and simvastatin, accounting for 9.35-26.96% of the initial loadings. However, the sorption of the other selected PhACs was negligible. The overall pharmaceutical consumption in Chongqing, China, was back-calculated based on influent concentration by considering the pharmacokinetics of PhACs in humans. The back-estimated usage was in good agreement with usage of ofloxacin (agreement ratio: 72.5%). However, the back-estimated usage of PhACs requires further verification. Generally, the average influent mass loads and back-calculated annual per capita consumption of the selected antibiotics were comparable to or higher than those reported in developed countries, while the case of other target PhACs was opposite.

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

    Bos, Marian E H; Nielen, Mirjam; Koch, Guus; Bouma, Annemarie; De Jong, Mart C M; Stegeman, Arjan


    To optimize control of an avian influenza outbreak knowledge of within-flock transmission is needed. This study used field data to estimate the transmission rate parameter (beta) and the influence of risk factors on within-flock transmission of highly pathogenic avian influenza (HPAI) H7N7 virus in the 2003 epidemic in The Netherlands. The estimation is based on back-calculation of daily mortality data to fit a susceptible-infectious-dead format, and these data were analysed with a generalized linear model. This back-calculation method took into account the uncertainty of the length of the latent period, the survival of an infection by some birds and the influence of farm characteristics. After analysing the fit of the different databases created by back-calculation, it could be concluded that an absence of the latency period provided the best fit. The transmission rate parameter (beta) from these field data was estimated at 4.50 per infectious chicken per day (95% CI: 2.68-7.57), which was lower than what was reported from experimental data. In contrast to general belief, none of the studied risk factors (housing system, flock size, species, age of the birds in weeks and date of depopulation) had significant influence on the estimated beta.


    Institute of Scientific and Technical Information of China (English)

    梅世龙; E.C. Drumm; 黄宝山; 何文斌; 左刚


    A 2.5 meter diameter 49 m long concrete shaft foundation socketed into rock was load tested with a system of balanced internal jacks similar to the O-cell test. This internal loading provided an examination of the skin friction response both above and below the load jack. Based on the observed response, the properties for the interface between the concrete and rock-socket were back-calculated. Since the observed side resistance at the interface was greater than the resistance due solely to friction, an apparent interface cohesion term was included by idealizing small asperities along the rock socket. The use of idealized asperities appears to be an effective way to model cohesion at the rock-concrete contact.

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

    Institute of Scientific and Technical Information of China (English)

    杨国良; 钟雯; 黄晓韵; 梁思敏; 何慧慧; 陈家驹


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

  12. Backcalculation of Composite Pavement Layer Moduli (United States)


    Tensile Method GAAF Dynamic Modulus 6.483695 -0.00012 1.9798 0.047173 0.000027 by Longitudinal Method BDRS Total Resilient 7.050392 -0.00582 1.2418...Method BORS Dynamic Modulus 6.665788 -0.00227 1.3499 0.037064 0.000358 by Longitudinal Method * Curve families have the general form: LOGl 0(Ec) = A0

  13. Evaluation of Procedures for Backcalculation of Airfield Pavement Moduli (United States)


    94/11. McLean, VA: U.S. Department of Transportation , Federal Highway Administration (FHWA). ERDC/GSL TR-15-31 143 Lytton, R.L. 1989...compared to processes utilized by other transportation agencies and those proposed by academia. Airfield deflection data were then analyzed using current...aircraft. As tire pressures and aircraft weights have increased steadily during this time, the design and evaluation software– Pavement- Transportation

  14. Dietary back-calculation using stable isotopes: can activities of enzymes involved in amino acid metabolism be used to improve estimates of trophic shifts in fish? (United States)

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


    The aim of this study was (1) to assess the effects of dietary protein content and feeding level on trophic shifts of C and N isotopes (Delta delta(13)C(tissue-diet) and Delta delta(15)N(tissue-diet)) and (2) to test whether the measurement of the activities of two enzymes involved in the metabolism of amino acids could improve the accuracy of estimation of the trophic shifts of C and N isotopes. For this, 36 Nile tilapia (Oreochromis niloticus) were kept under controlled conditions for 8 weeks and fed at three different levels (2, 4 and 8 g kg(-0.8) d(-1)) with three diets differing in their protein content only (20, 29 and 39 %). For each fish, food to fish body trophic shifts of C and N isotopes were measured as well as the hepatic activities of aspartate aminotransferase (ASAT) and glutamate dehydrogenase (GDH). The feeding level affected the activities of ASAT and GDH as well as the trophic shifts of C and N isotopes significantly but the dietary protein content had no significant effect except on the specific activity of ASAT. Fish fed at the lowest level had significantly higher trophic shifts of C and N isotopes than fish fed at higher levels. The trophic shifts were significantly lower in fish with a high protein utilisation. Values of the 'goodness-of-fit' for linear regressions between enzyme activities and trophic shifts were low. Thus, activities of ASAT and GDH are not suitable for predicting estimates of trophic shifts in situations where the amount of food consumed or the dietary protein content is not known. In further studies, activities of enzymes involved in the metabolism of amino acids combined with measurements of the activities of other enzymes should be used to try and improve the accuracy of estimates of trophic shifts.

  15. Relación entre el módulo resiliente hallado por retrocálculo y el encontrado en ensayos de laboratorio / Relation between resilient modulus found for backcalculation and found in laboratory test programs


    Leal Noriega, Mario Helberto


    En el proyecto de investigación se determinó la relación existente entre el módulo resiliente hallado por retrocálculo y el encontrado en ensayos de laboratorio, analizando la influencia de parámetros como la humedad y la temperatura en los resultados obtenidos. Para cumplir con el objetivo se desarrollaron pruebas de campo con deflectómetro de impacto, así como ensayos de módulo resiliente y módulo dinámico en laboratorio, sobre materiales granulares y de mezcla asfáltica respectivamente. ...

  16. Bayesian hierarchical model used to analyze regression between fish body size and scale size: application to rare fish species Zingel asper

    Directory of Open Access Journals (Sweden)

    Fontez B.


    Full Text Available Back-calculation allows to increase available data on fish growth. The accuracy of back-calculation models is of paramount importance for growth analysis. Frequentist and Bayesian hierarchical approaches were used for regression between fish body size and scale size for the rare fish species Zingel asper. The Bayesian approach permits more reliable estimation of back-calculated size, taking into account biological information and cohort variability. This method greatly improves estimation of back-calculated length when sampling is uneven and/or small.

  17. 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


    IntroductionHuman exposure to chemicals may be estimated by back-calculating urinary concentrations resulting from biomonitoring studies if knowledge of the chemical's toxicokinetic properties is available.AimTo review available toxicokinetic data for back-calculating urinary concentrations into ...

  18. 75 FR 51671 - Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Final Exclusion (United States)


    ... (carcinogenic risk of 10 -5 and non-cancer hazard index of 1.0). The DRAS program can back-calculate the... statement, to attest to the truth and accuracy of the data submitted: Under civil and criminal penalty of... personally verify its (their) truth and accuracy I certify as the company official having...

  19. 76 FR 5110 - Hazardous Waste Management System; Identification and Listing of Hazardous Waste; Proposed Rule (United States)


    ... non-cancer hazard index of 1.0), the DRAS program can back-calculate the acceptable receptor well... along with all data a signed copy of the following certification statement, to attest to the truth and...) identified section(s) of this document for which I cannot personally verify its (their) truth and accuracy,...

  20. Seroincidence of non-typhoid Salmonella infections

    DEFF Research Database (Denmark)

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


    that enabled a back-calculation of the annual seroincidence of Salmonella based on measurements of specific antibodies. The aim of the present study was to determine the seroincidence in two convenience samples from 2012 (Danish blood donors, n = 500, and pregnant women, n = 637) and a community-based sample...

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

    DEFF Research Database (Denmark)

    Hajlane, A.; Miettinen, A.; Madsen, Bo;


    The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro...

  2. 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


    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%.

  3. Estimation of axial stiffness of plant fibres from compaction of non-woven mats (United States)

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


    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-plane randomly oriented fibre mats. The model by Toll is used to relate the load-displacement curve from the test to the Young modulus of the fibre, taking into account the natural variability in fibre cross section. Several tests have been performed on hemp fibre mats and compared with results from single-fibre tensile testing. The average back-calculated Young's modulus of the fibres was 45 GPa, whereas the average value from tensile testing ranged from 30 to 60 GPa. The straightforward compaction test can be useful in ranking of fibre stiffness, provided that the mat is composed of well-separated fibres and not of twisted yarns.

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

    DEFF Research Database (Denmark)

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


    -plane randomly oriented fibre mats. The model by Toll is used to relate the load-displacement curve from the test to the Young modulus of the fibre, taking into account the natural variability in fibre cross section. Several tests have been performed on hemp fibre mats and compared with results from single......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......-fibre tensile testing. The average back-calculated Young's modulus of the fibres was 45 GPa, whereas the average value from tensile testing ranged from 30 to 60 GPa. The straightforward compaction test can be useful in ranking of fibre stiffness, provided that the mat is composed of well-separated fibres...

  5. 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.


    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......-calculated days of first feeding (DFF), was narrow compared to the extended spawning season of sprat in the Baltic Sea (mean +/- SD = 22 June +/- 14.1 days) and indicated that only individuals born in summer survived until October 2002. Within the group of survivors, individuals born later in the season exhibited...... faster larval, but more rapidly decreasing juvenile growth rates than earlier born conspecifics. Back-calculated larval growth rates of survivors (0.48-0.69 mm day(-1)) were notably higher than those previously reported for average larval sprat populations, suggesting that the YoY population...

  6. Accurate estimation of the elastic properties of porous fibers

    Energy Technology Data Exchange (ETDEWEB)

    Thissell, W.R.; Zurek, A.K.; Addessio, F.


    A procedure is described to calculate polycrystalline anisotropic fiber elastic properties with cylindrical symmetry and porosity. It uses a preferred orientation model (Tome ellipsoidal self-consistent model) for the determination of anisotropic elastic properties for the case of highly oriented carbon fibers. The model predictions, corrected for porosity, are compared to back-calculated fiber elastic properties of an IM6/3501-6 unidirectional composite whose elastic properties have been determined via resonant ultrasound spectroscopy. The Halpin-Tsai equations used to back-calculated fiber elastic properties are found to be inappropriate for anisotropic composite constituents. Modifications are proposed to the Halpin-Tsai equations to expand their applicability to anisotropic reinforcement materials.

  7. The effect of submarine CO2vents on seawater: Implications for detection of subsea carbon sequestration leakage


    Botnen, Helle Augdal; Omar, Abdirahman M.; Thorseth, Ingunn; Johannessen, Truls; Alendal, Guttorm


    The effect of submarine carbon dioxide (CO2) vents on seawater carbonate chemistry have been determined using hydrographical and marine carbonate data obtained from two submarine hydrothermal vent fields, as well as a reference station, all near the Jan Mayen Island in the Norwegian-Greenland Sea. We have shown that one can successfully determine the excess carbon that enters the seawater from the vents by applying a modified version of a back-calculation technique, which is traditionally use...

  8. Detecting age-structured effects in growth performance of coral reef fish juveniles


    Mellin, Camille; Galzin, R.; Ponton, Dominique; Vigliola, Laurent


    The growth performance of coral reef fish juveniles collected in different habitats is often used as a proxy for habitat quality for juveniles. However, back-calculated growth trajectories of juveniles may be age-structured, for instance, because of potential differences in initial offspring size and/or quality or size-selective mortality. A novel approach is proposed to isolate growth performance of coral reef fish juveniles from potential age-based factors. Juveniles of Chromis viridis (Pom...

  9. A study of methods to estimate debris flow velocity (United States)

    Prochaska, A.B.; Santi, P.M.; Higgins, J.D.; Cannon, S.H.


    Debris flow velocities are commonly back-calculated from superelevation events which require subjective estimates of radii of curvature of bends in the debris flow channel or predicted using flow equations that require the selection of appropriate rheological models and material property inputs. This research investigated difficulties associated with the use of these conventional velocity estimation methods. Radii of curvature estimates were found to vary with the extent of the channel investigated and with the scale of the media used, and back-calculated velocities varied among different investigated locations along a channel. Distinct populations of Bingham properties were found to exist between those measured by laboratory tests and those back-calculated from field data; thus, laboratory-obtained values would not be representative of field-scale debris flow behavior. To avoid these difficulties with conventional methods, a new preliminary velocity estimation method is presented that statistically relates flow velocity to the channel slope and the flow depth. This method presents ranges of reasonable velocity predictions based on 30 previously measured velocities. ?? 2008 Springer-Verlag.

  10. Structural analyses of a rigid pavement overlaying a sub-surface void (United States)

    Adam, Fatih Alperen

    Pavement failures are very hazardous for public safety and serviceability. These failures in pavements are mainly caused by subsurface voids, cracks, and undulation at the slab-base interface. On the other hand, current structural analysis procedures for rigid pavement assume that the slab-base interface is perfectly planar and no imperfections exist in the sub-surface soil. This assumption would be violated if severe erosion were to occur due to inadequate drainage, thermal movements, and/or mechanical loading. Until now, the effect of erosion was only considered in the faulting performance model, but not with regards to transverse cracking at the mid-slab edge. In this research, the bottom up fatigue cracking potential, caused by the combined effects of wheel loading and a localized imperfection in the form of a void below the mid-slab edge, is studied. A robust stress and surface deflection analysis was also conducted to evaluate the influence of a sub-surface void on layer moduli back-calculation. Rehabilitative measures were considered, which included a study on overlay and fill remediation. A series regression of equations was proposed that provides a relationship between void size, layer moduli stiffness, and the overlay thickness required to reduce the stress to its original pre-void level. The effect of the void on 3D pavement crack propagation was also studied under a single axle load. The amplifications to the stress intensity was shown to be high but could be mitigated substantially if stiff material is used to fill the void and impede crack growth. The pavement system was modeled using the commercial finite element modeling program Abaqus RTM. More than 10,000 runs were executed to do the following analysis: stress analysis of subsurface voids, E-moduli back-calculation of base layer, pavement damage calculations of Beaumont, TX, overlay thickness estimations, and mode I crack analysis. The results indicate that the stress and stress intensity are, on

  11. Engineering geologic and geotechnical analysis of paleoseismic shaking using liquefaction effects: Field examples (United States)

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


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

  12. Noise-tolerant inverse analysis models for nondestructive evaluation of transportation infrastructure systems using neural networks (United States)

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


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

  13. "Comparison of some Structural Analyses Methods used for the Test Pavement in the Danish Road Testing Machine

    DEFF Research Database (Denmark)

    Baltzer, S.; Zhang, W.; Macdonald, R.;


    A flexible test pavement, instrumented to measure stresses and strains in the three primary axes with the upper 400 mm of the subgrade, has been constructed and load tested in the Danish Road Testing Machine (RTM). One objective of this research, which is part of the International Pavement Subgrade...... methods used for the RTM test pavement with data from FWD testing undertaken after the construction and loading programmes. Multilayer linear elastic forward and backcalculation methods, a finite element program and MS Excel spreadsheet based methods are compared....

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

    DEFF Research Database (Denmark)

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


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

  15. Understanding of bridge cable vibrations and the associate flow-field through the full-scale monitoring of vibrations and Wind

    DEFF Research Database (Denmark)

    Acampora, Antonio

    such as cable vibrations amplitude, cables frequencies involved in the vibrations, wind directions, wind speeds and rainfall rates. Those indications are used to select full-scale cables vibrations for further analyses. In particular, aerodynamic damping is investigated by means of system identification...... procedures based on the Markov-Block-Hankel matrix. From identified aerodynamic damping from full-scale data, back-calculated aerodynamic coefficients of Øresund Bridge cable were obtained. Wind tunnel tests were performed on a scaled model of the actual cables both in dynamic and static tests to investigate...

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

    Directory of Open Access Journals (Sweden)

    Potvin R


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

  17. Age, maturation, and population structure of the Humboldt squid Dosidicus gigas off the Peruvian Exclusive Economic Zones (United States)

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


    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.

  18. Evaluation of accelerated deterioration in NAPTF flexible test pavements

    Institute of Scientific and Technical Information of China (English)

    Kasthurirangan GOPALAKRISHNAN


    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.

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

    Directory of Open Access Journals (Sweden)

    Augusto Cannone Falchetto


    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.

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

    Directory of Open Access Journals (Sweden)

    Paulo Duarte-Neto

    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.

  1. Ammonia emissions from an anaerobic digestion plant estimated using atmospheric measurements and dispersion modelling. (United States)

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


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

  2. Enteric methane emissions from German dairy cows

    DEFF Research Database (Denmark)

    Dammgen, U; Rosemann, C; Haenel, H D


    Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

  3. Was the increase in culture-confirmed Campylobacter infections in Denmark during the 1990s a surveillance artefact? (United States)

    Emborg, Hanne-Dorthe; Teunis, Peter; Simonsen, Jacob; Krogfelt, Karen A; Jørgensen, Charlotte S; Takkinen, Johanna; Mølbak, Kåre


    In 1991, 1999 and 2006, randomly selected individuals from the Danish Central Personal Register provided a serum sample. From individuals aged 30 years and above, 500 samples from each year were analysed for Campylobacter IgG, IgA and IgM antibodies using a direct ELISA method. We applied a seroincidence calculator available from the European Centre for Disease Prevention and Control to perform a mathematical back-calculation to estimate the annual Campylobacter seroincidence in the Danish population. The estimated Campylobacter seroincidence did not differ significantly between the 1991, 1999 and 2006 studies although the reported number of culture-confirmed cases of Campylobacter infection increased 2.5 fold from 1993 to 1999 among individuals aged 30 years and above. This suggests that Campylobacter was widely present in the Danish population before the increase in poultry-associated clinical Campylobacter infections observed from 1993 to 2001 among individuals of this age groups.

  4. Atmospheric deposition of toxaphene to eastern north America derived from peat accumulation (United States)

    Rapaport, R. A.; Eisenreich, S. J.

    Dated peat cores from Minnesota east to Nova Scotia analyzed for toxaphene provided spatial variation in historical and recent atmospheric fluxes and an atmospheric input function for toxaphene extending over the past 40 years. This input function is consistent with toxaphene production data and the input of a well documented insecticide, DDT. Total core burdens of toxaphene across a west to east transect were highest in the upper midwest and Nova Scotia, with recent peat accumulation rates ranging from 0.5 to 9 μg m -2a -1. Atmospheric concentrations of toxaphene, back-calculated from accumulation rates in peat, range from 8 to 150 pg m -3, in agreement with recently-measured concentrations in remote atmospheres. Recent atmospheric inputs of toxaphene are two to four times those of PCBs and DDT, respectively.

  5. 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


    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.

  6. Modelling Illicit Drug Fate in Sewers for Wastewater-Based Epidemiology

    DEFF Research Database (Denmark)

    Ramin, Pedram

    application for back-calculation at catchment level. In this thesis, 16 drug biomarkers were selected based on their ubiquitous occurrence in wastewater, and include cocaine, mephedrone, methadone, heroin, codeine and tetrahydrocannabinol (THC) and their respective major human metabolites. In-sewer processes...... biotransformation e.g., almost complete removal of heroin and morphine-3-glucuronide after 12 h in batch experiments with raw wastewater. It was further observed that sewer biofilms can enhance biotransformation of a number of selected chemicals, such as benzoylecgonine and 6-monoacetylmorphine. Overall, redox......-sewer processes and sampling. It was found that ignoring in-sewer processes for cocaine and its metabolite benzoylecgonine can add up to 11% (median value for a large catchment) error in daily cocaine consumption estimates. This error was 43% and 11% for estimates of daily heroin use with 6-monoacetylmorphine...

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

    DEFF Research Database (Denmark)

    Plósz, Benedek G.; Reid, Malcolm J.; Borup, Morten


    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...

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

    DEFF Research Database (Denmark)

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


    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...

  9. Labview virtual instruments for calcium buffer calculations. (United States)

    Reitz, Frederick B; Pollack, Gerald H


    Labview VIs based upon the calculator programs of Fabiato and Fabiato (J. Physiol. Paris 75 (1979) 463) are presented. The VIs comprise the necessary computations for the accurate preparation of multiple-metal buffers, for the back-calculation of buffer composition given known free metal concentrations and stability constants used, for the determination of free concentrations from a given buffer composition, and for the determination of apparent stability constants from absolute constants. As implemented, the VIs can concurrently account for up to three divalent metals, two monovalent metals and four ligands thereof, and the modular design of the VIs facilitates further extension of their capacity. As Labview VIs are inherently graphical, these VIs may serve as useful templates for those wishing to adapt this software to other platforms.

  10. Trophic flexibility by roach Rutilus rutilus in novel habitats facilitates rapid growth and invasion success. (United States)

    Hayden, B; Massa-Gallucci, A; Harrod, C; O'grady, M; Caffrey, J; Kelly-Quinn, M


    Stable isotope and gut content analyses, in conjunction with backcalculated length-at-age estimates of growth, were employed to examine the relationship between trophic ecology and growth rate of a successful invader, Rutilus rutilus, in eight lakes in Ireland. The data revealed that R. rutilus was a trophic generalist in Irish lakes. It utilized a greater proportion of pelagic resources in mesotrophic lakes than in eutrophic lakes, potentially due to a greater density of benthic macroinvertebrates in eutrophic systems. The species was characterized by a large dietary and isotopic niche width and high temporal and spatial variations in diet. Growth rates were typical of those found in the native range of the species and were unrelated to either lake productivity or fish's diet. A generalist trophic ecology confers significant advantages on an invasive species, allowing it to exploit a variety of novel resources and fluctuations in prey availability.

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

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mohamed Al-beak


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

  12. Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing

    DEFF Research Database (Denmark)

    Ulrich, Clara; Hansen, Jakob Hemmer; Boje, Jesper


    A multi-disciplinary study was conducted to clarify stock identity and connectivity patterns in the populations of European plaice (Pleuronectes platessa) in the Skagerrak-Kattegat transition area between the Eastern North Sea and the Baltic Sea. Five independent biological studies were carried out...... in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing....... Hydrogeographical drift modelling suggested that some North Sea juveniles could settle along the coast line of the Skagerrak and the Kattegat. Tagging data suggested that both juveniles and adult fish from the North Sea perform feeding migrations into Skagerrak in summer/autumn. Finally, survey data suggested...

  13. Spin-selective correlation experiment for measurement of long-range J couplings and for assignment of (R/S) enantiomers from the residual dipolar couplings and DFT. (United States)

    Nath, Nilamoni; Suryaprakash, N


    We report the C-HETSERF experiment for determination of long- and short-range homo- and heteronuclear scalar couplings ((n)J(HH) and (n)J(XH), n ≥ 1) of organic molecules with a low sensitivity dilute heteronucleus in natural abundance. The method finds significant advantage in measurement of relative signs of long-range heteronuclear total couplings in chiral organic liquid crystal. The advantage of the method is demonstrated for the measurement of residual dipolar couplings (RDCs) in enantiomers oriented in the chiral liquid crystal with a focus to unambiguously assign R/S designation in a 2D spectrum. The alignment tensor calculated from the experimental RDCs and with the computed structures of enantiomers obtained by DFT calculations provides the size of the back-calculated RDCs. Smaller root-mean-square deviations (rmsd) between experimental and calculated RDCs indicate better agreement with the input structure and its correct designation of the stereogenic center.

  14. Age-structured mark-recapture analysis: A virtual-population-analysis-based model for analyzing age-structured capture-recapture data (United States)

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


    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.

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

    DEFF Research Database (Denmark)

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


    , and that the LCG model is successful in extracting a population abundance signal fromthe data. In this regard, the model performed appreciably better than a more commonly used raising algorithm based on survey swept-area estimates. Therefore, the LCG model was expanded to include data from the entire survey time...... the correlation between the derived annual recruitment index and recruitment estimated by backcalculation of adult mackerel data. Square root transformation led to the strongest correlation, so this is recommended for further analysis of mackerel abundance. Finally,we provide maps of spatial distributions......, showing that the most important nursery areas are around Ireland, north and west of Scotland, in the northern North Sea north of 598Nand, to some extent, also in the Bay of Biscay....

  16. Use of diagnostic bones to identify and estimate original lengths of ingested prey fishes (United States)

    Hansel, H.C.; Duke, S.D.; Lofy, P.T.; Gray, G.A.


    We examined and measured cleithra, dentaries, opercles, and pharyngeal arches – bones found to persist during digestion of most prey fish – to identify 24 prey fish species and back-calculate their original fork length. Eighteen of the 24 species examined could be easily distinguished; however, for certain congenerics, identification was neither consistent nor reliable for all bones within the size ranges examined. Relations between bone length and fish length were linear for 14 species for which the sample sizes were adequate (N > 30); coefficients of determination (r 2) ranged from 0.79 to 0.99. Diagnostic characteristics and measurements of these bones provided reliable identification of genera and species and estimates of original fork lengths of partly digested prey fish from three predators. This method, compared with that of examining only prey fish in a measurable condition, greatly increased the amount of dietary information available from gut analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hagn, Franz, E-mail:; Wagner, Gerhard, E-mail: [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States)


    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.

  18. Statistical estimations forPlasmodium vivaxmalaria in South Korea

    Institute of Scientific and Technical Information of China (English)

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


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

  19. Rock mass characterisation and stability analyses of excavated slopes (United States)

    Zangerl, Christian; Lechner, Heidrun


    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

  20. Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes (United States)

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


    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.

  1. 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


    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

  2. A method for intercalibration of U-Th-Pb and 40Ar- 39Ar ages in the Phanerozoic (United States)

    Villeneuve, Mike; Sandeman, Hamish A.; Davis, William J.


    The increasing analytical precision of 40Ar- 39Ar geochronological data and its use in studies that combine U-Pb and 40Ar- 39Ar data has necessitated derivation of a means to intercalibrate ages between the two isotopic systems. The primary determinants inhibiting accurate cross calibration are uncertainty in decay constant values and uncertainty in 40Ar∗/ 40K (usually presented as apparent age) for 40Ar- 39Ar standards, notably those derived from the Fish Canyon Tuff. By utilizing a monazite- and biotite bearing Oligocene ash flow tuff (MAC-83) as the primary standard material, precise U-Th-Pb and 40Ar- 39Ar ages can be derived. Because both isotopic systems should reflect closure during the instantaneous eruption event, the 24.21 ± 0.10 Ma 207Pb/ 235U age should match the age resulting from 40Ar- 39Ar biotite analysis. This forced equivalence will partly offset the effects of decay constant uncertainty. Furthermore, by co-irradiating Fish Canyon Tuff sanidine with MAC-83 biotite, the apparent age for Fish Canyon Tuff sanidine is back-calculated to 27.98 ± 0.15 Ma, relative to the MAC-83 207Pb/ 235U age. Hence, intercalibration between the two isotopic systems in a relative sense can be accomplished, allowing for a direct and valid comparison of ages. It is also shown that forcing equivalence of the two isotopic systems minimizes the effect of decay constant uncertainty for samples of Phanerozoic age.

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

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

    Directory of Open Access Journals (Sweden)

    K. Schraml


    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.

  5. Semi-physical Identification and State Estimation of Energy Intake for Interventions to Manage Gestational Weight Gain (United States)

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


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

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


    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.

  7. Evaluation of different smoking habits during music festivals through wastewater analysis. (United States)

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


    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.

  8. 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


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

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


    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.

  10. Dynamic Modeling of Pavements with Application to Deflection Measurements

    DEFF Research Database (Denmark)

    Madsen, Stine Skov

    of long time simulations without disruptions from the boundaries. The equations are formulated in a moving frame of reference such that the domain is following the load, which ensures that the size of the model is kept small regardless of simulation time frame. A parametric study for finding optimal PML...... parameters is conducted [P1]. The efficiency of the PML formulation is tested in a half space and in a layered halfspace. The effect of load speed is investigated as well as the influence of modulus ratio between surface layer and the underlying soil for different load speeds. Wave propagation is illustrated...... for various load speeds in both 2D and 3D. The differences in response mag-nitude and attenuation rate of 2D and 3D waves are illustrated as well. The model is applied for backcalculation of mechanical properties from FWD experiments with load-time histories of various pulse durations and load magnitudes [P2...

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions. (United States)

    Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad


    Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

  13. Estimation of Joule heating and its role in nonlinear electrical response of Tb0.5Sr0.5MnO3 single crystal (United States)

    Nhalil, Hariharan; Elizabeth, Suja


    Highly non-linear I-V characteristics and apparent colossal electro-resistance were observed in non-charge ordered manganite Tb0.5Sr0.5MnO3 single crystal in low temperature transport measurements. Significant changes were noticed in top surface temperature of the sample as compared to its base while passing current at low temperature. By analyzing these variations, we realize that the change in surface temperature (ΔTsur) is too small to have caused by the strong negative differential resistance. A more accurate estimation of change in the sample temperature was made by back-calculating the sample temperature from the temperature variation of resistance (R-T) data (ΔTcal), which was found to be higher than ΔTsur. This result indicates that there are large thermal gradients across the sample. The experimentally derived ΔTcal is validated with the help of a simple theoretical model and estimation of Joule heating. Pulse measurements realize substantial reduction in Joule heating. With decrease in sample thickness, Joule heating effect is found to be reduced. Our studies reveal that Joule heating plays a major role in the nonlinear electrical response of Tb0.5Sr0.5MnO3. By careful management of the duty cycle and pulse current I-V measurements, Joule heating can be mitigated to a large extent.

  14. Estimating the use of antibiotics for humans across China. (United States)

    Bu, Qingwei; Wang, Bin; Huang, Jun; Liu, Kai; Deng, Shubo; Wang, Yujue; Yu, Gang


    The present study aimed to propose a method to estimate the spatially resolved dataset for human-use antibiotics, which are highly needed in exposure models dealing with regions of various environmental characteristics. In this study, a regression model describing the relationship between the use of antibiotics and a set of socio-economic determinants was developed. It has been demonstrated that economic status (expressed using per capita gross domestic production) dominates the antibiotic use at least in China. Linear regression analysis was used to build the model, resulting in high goodness-of-fit, R(2) (>0.75). Internal and external validations along with residue plot indicated that the model was robust and predictive. The model was successfully applied to allocate the use of antibiotics in China in 2011 at national-, provincial-, prefectural-, and county-level, which are comparable to that back-calculated from the available data of wastewater analysis in some cities. Antibiotic uses were higher in East China than other regions and it was found that uses of total antibiotics vary among Chinese counties on four orders of magnitude (0.186-1645 t antibiotics per year per county). Also management practice could be worked out according to our exploration of the impact transition of social-economic factors on antibiotic uses. To our knowledge, this is the first endeavor to explore this economic dominated relationship for estimating spatially resolved use map of antibiotics in China.

  15. Quantitation of a novel metalloporphyrin drug in plasma by atomic absorption spectroscopy. (United States)

    Hoffman, K L; Feng, M R; Rossi, D T


    A bioanalytical method to quantify cobalt mesoporphyrin (CoMP), a novel therapeutic agent, in plasma has been developed and validated. The approach involves atomic absorption spectroscopy to determine total cobalt in a sample and a back-calculation of the amount of compound present. Endogenous plasma cobalt concentrations were small ( <0.2 ng/ml(-1) Co in rat plasma) in comparison to the quantitation limit (4.5 ng/ml(-1) Co). The inter-day imprecision of the method was 10.0% relative standard deviation (RSD) and the inter-day bias was +/- 8.0% relative error (RE) over a standard curve range of 4.5- 45.0 ng/ml(-1) Co. Because it quantifies total cobalt, the method cannot differentiate between parent drug and metabolites, but negligible metabolism allows reliable estimates of the actual parent drug concentration. A correlation study between the atomic absorption method and 14C-radiometry demonstrated excellent agreement (r = 0.9868, slope = 1.041 +/- 0.028, intercept = 223.7 +/- 190.0) and further substantiated the accuracy of the methods. Methodology was successfully applied to a pharmacokinetic study of CoMP in rat, with pharmacokinetic parameter estimation. The elimination half-lives, after intra-muscular and subcutaneous administration, were 7.7 and 8.8 days, respectively.

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

    Directory of Open Access Journals (Sweden)

    Tomislav Vladic


    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.

  17. Ab initio diffuse-interface model for lithiated electrode interface evolution (United States)

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


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

  18. 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)


    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.

  19. Structural Analysis and Optimization of a Composite Fan Blade for Future Aircraft Engine (United States)

    Coroneos, Rula M.; Gorla, Rama Subba Reddy


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

  20. Seroincidence of non-typhoid Salmonella infections: convenience vs. random community-based sampling. (United States)

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


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

  1. Defining Product Intake Fraction to Quantify and Compare Exposure to Consumer Products. (United States)

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


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

  2. The apparent elastic modulus of the juxtarticular subchondral bone of the femoral head. (United States)

    Brown, T D; Vrahas, M S


    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.

  3. Variability and connectivity of plaice populations from the Eastern North Sea to the Baltic Sea, part II. Biological evidence of population mixing (United States)

    Ulrich, Clara; Hemmer-Hansen, Jakob; Boje, Jesper; Christensen, Asbjørn; Hüssy, Karin; Sun, Hailu; Clausen, Lotte Worsøe


    A multi-disciplinary study was conducted to clarify stock identity and connectivity patterns in the populations of European plaice (Pleuronectes platessa) in the Skagerrak-Kattegat transition area between the Eastern North Sea and the Baltic Sea. Five independent biological studies were carried out in parallel. Genetic markers suggested the existence of different genetic populations in the transition area. Growth backcalculation with otoliths resulted in significant although limited differences in growth rates between North Sea and Skagerrak, indicating weak differentiation or important mixing. Hydrogeographical drift modelling suggested that some North Sea juveniles could settle along the coast line of the Skagerrak and the Kattegat. Tagging data suggested that both juveniles and adult fish from the North Sea perform feeding migrations into Skagerrak in summer/autumn. Finally, survey data suggested that Skagerrak also belongs to the area distribution of North Sea plaice. The outcomes of the individual studies were then combined into an overall synthesis. The existence of some resident components was evidenced, but it was also demonstrated that North Sea plaice migrate for feeding into Skagerrak and might constitute a large share of the catches in this area. The mixing of different populations within a management area has implications for stock assessment and management. Choice must be made to either lump or split the populations, and the feasibility and constraints of both options are discussed. The outcomes of this work have directly influenced the management decisions in 2015.

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

    Energy Technology Data Exchange (ETDEWEB)

    Winefordner, J. D.


    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.

  5. Modeling Human Exposure to Phthalate Esters: A Comparison of Indirect and Biomonitoring Estimation Methods (United States)

    Clark, Kathryn E.; David, Raymond M.; Guinn, Richard; Kramarz, Kurt W.; Lampi, Mark A.; Staples, Charles A.


    Humans are potentially exposed to phthalate esters (PEs) through ingestion, inhalation, and dermal contact. Studies quantifying exposure to PEs include “biomarker studies” and “indirect studies.” Biomarker studies use measurements of PE metabolites in urine to back-calculate exposure to the parent diester, while indirect studies use the concentration of the PE in each medium of exposure and the rate of intake of that medium to quantify intake of the PE. In this review, exposure estimates from biomarker and indirect studies are compiled and compared for seven PEs to determine if there are regional differences and if there is a preferred approach. The indirect and biomarker methods generally agree with each other within an order of magnitude and discrepancies are explained by difficulties in accounting for use of consumer products, uncertainty concerning absorption, regional differences, and temporal changes. No single method is preferred for estimating intake of all PEs; it is suggested that biomarker estimates be used for low molecular weight PEs for which it is difficult to quantify all sources of exposure and either indirect or biomarker methods be used for higher molecular weight PEs. The indirect methods are useful in identifying sources of exposure while the biomarker methods quantify exposure. PMID:23087593

  6. Amphetamines in wastewater of the city Poznań (Poland)--estimation of drug abuse. (United States)

    Nowicki, Piotr; Klos, Jolanta; Kokot, Zenon J


    The aim of the study was to determine the profile of amphetamines consumed by a community in Poland. Amphetamine, methamphetamine and MDMA (ecstasy) were detected in wastewater samples collected from the main Wastewater Treatment Plant in the city of Poznań (about 687 000 people) using liquid chromatography/tandem mass spectrometry (LC-MS-MS). Back-calculations used in the sewage epidemiology approach were applied to estimate the level of consumption of the drugs being analyzed. These types of studies were carried out for the first time in Poland for a considerable period--from June 2009 to December 2010. The analysis of variance (ANOVA) confirmed significant monthly differences in amphetamine consumption. The concentration of amphetamine, methamphetamine and MDMA in wastewater samples and the levels of their consumption were lower than reported in other European countries, but unexpectedly, the ratio of consumed methamphetamine to MDMA and the consumption level of methamphetamine were relatively high. This study shows that sewage epidemiology is a promising tool, especially when combined with classical methods, to estimate illicit drugs use in a particular population. Therefore, efforts should be made to monitor the profiles and consumption levels of drugs and to extend the scope of the research to other illicit substances, especially cannabinoids and cocaine.

  7. Coupling survey data with drift model results suggests that local spawning is important for Calanus finmarchicus production in the Barents Sea (United States)

    Kvile, Kristina Øie; Fiksen, Øyvind; Prokopchuk, Irina; Opdal, Anders Frugård


    The copepod Calanus finmarchicus is an important part of the diet for several large fish stocks feeding in the Atlantic waters of the Barents Sea. Determining the origin of the new generation copepodites present on the Barents Sea shelf in spring can shed light on the importance of local versus imported production of C. finmarchicus biomass in this region. In this study, we couple large-scale spatiotemporal survey data (> 30 years in both Norwegian Sea and Barents Sea areas) with drift trajectories from a hydrodynamic model to back-calculate and map the spatial distribution of C. finmarchicus from copepod to egg, allowing us to identify potential adult spawning areas. Assuming the adult stage emerges from overwintering in the Norwegian Sea, our results suggest that copepodites sampled at the Barents Sea entrance are a mix of locally spawned individuals and long-distance-travellers advected northwards along the Norwegian shelf edge. However, copepodites sampled farther east in the Barents Sea (33°30‧E) are most likely spawned on the Barents Sea shelf, potentially from females that have overwintered locally. Our results support that C. finmarchicus dynamics in the Barents Sea are not, at least in the short-term, solely driven by advection from the Norwegian Sea, but that local production may be more important than commonly believed.

  8. Pavement thickness and stabilised foundation layer assessment using ground-coupled GPR (United States)

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


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

  9. Fast-slow life history is correlated with individual differences in movements and prey selection in an aquatic predator in the wild. (United States)

    Nakayama, Shinnosuke; Rapp, Tobias; Arlinghaus, Robert


    Fast and slow life histories are proposed to covary with consistent individual differences in behaviour, but little is known whether it holds in the wild, where individuals experience natural fluctuations of the environment. We investigated whether individual differences in behaviour, such as movement traits and prey selection, are linked to variation in life-history traits in Eurasian perch (Perca fluviatilis) in the wild. Using high-resolution acoustic telemetry, we collected the positional data of fish in a whole natural lake and estimated individual movement traits by fitting a two-state correlated random walk model. Prey selection was inferred from stable isotope analysis using scale samples. Life-history traits were estimated by fitting a biphasic growth model to an individual growth trajectory back-calculated from scale samples. Life-history traits were correlated with behavioural traits such as movements and prey selection. Individuals with higher reproductive effort were found to switch more frequently between active and inactive modes and show greater reliance on prey from pelagic pathways (indicated by lower δ(13) C). Further, individuals with faster juvenile growth were found to stay active for a longer time during the adult stage. Our results demonstrate the link between individual behavioural differences and fast-slow life-history traits under ecologically relevant conditions.

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

  11. A meta-analysis of estimates of the AIDS incubation distribution. (United States)

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


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

  12. A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture--Conceptual Framework. (United States)

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


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

  13. Abundance trends and status of the Little Colorado River population of humpback chub (United States)

    Coggins, L.G.; Pine, William E.; Walters, C.J.; Van Haverbeke, D. R.; Ward, D.; Johnstone, H.C.


    The abundance of the Little Colorado River population of federally listed humpback chub Gila cypha in Grand Canyon has been monitored since the late 1980s by means of catch rate indices and capture-recapture-based abundance estimators. Analyses of data from all sources using various methods are consistent and indicate that the adult population has declined since monitoring began. Intensive tagging led to a high proportion (>80%) of the adult population being marked by the mid-1990s. Analysis of these data using both closed and open abundance estimation models yields results that agree with catch rate indices about the extent of the decline. Survival rates for age-2 and older fish are age dependent but apparently not time dependent. Back-calculation of recruitment using the apparent 1990s population age structure implies periods of higher recruitment in the late 1970s to early 1980s than is now the case. Our analyses indicate that the U.S. Fish and Wildlife Service recovery criterion of stable abundance is not being met for this population. Also, there is a critical need to develop new abundance indexing and tagging methods so that early, reliable, and rapid estimates of humpback chub recruitment can be obtained to evaluate population responses to management actions designed to facilitate the restoration of Colorado River native fish communities. ?? Copyright by the American Fisheries Society 2006.

  14. Experimental, numerical and analytical modelling of a newly developed rockfall protective cable-net structure

    Directory of Open Access Journals (Sweden)

    S. Dhakal


    Full Text Available An innovative configuration of pocket-type rockfall protective cable-net structure, known as Long-span Pocket-type Rock-net (LPR, has been developed in Japan. The global performance of the proposed system was initially checked by the experimental (full-scale modelling. Given the various limitations of the physical experiments, particularly for the parametric study to have a detailed understanding of the newly developed system, a reliable and simplified method of numerical modelling is felt necessary. Again, given the sophistication involved with the method of numerical simulation, a yet simplified modelling approach may prove more effective. On top of this background, this paper presents a three-tier modelling of a design of LPR. After physical modelling, which has revealed that the displacement response may be taken more vital for LPR performance, Finite Element based numerical modelling is presented. The programme LS-DYNA is used and the models are calibrated and verified with the element- and structure-level experiments. Finally, a simple analytical modelling consisting of the equivalently linear and elastic, lumped-mass, single-degree-of-freedom system, capable of predicting the global displacement response, is proposed based on the basic principles of conservation of linear momentum and energy. The model is back-calculated and modified from the analyses of the verified numerical model.

  15. 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


    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.

  16. Estimating spawning times of Alligator Gar (Atractosteus spatula) in Lake Texoma, Oklahoma (United States)

    Snow, Richard A.; Long, James M.


    In 2013, juvenile Alligator Gar were sampled in the reservoir-river interface of the Red River arm of Lake Texoma. The Red River, which flows 860 km along Oklahoma’s border with Texas, is the primary in-flow source of Lake Texoma, and is impounded by Denison Dam. Minifyke nets were deployed using an adaptive random cluster sampling design, which has been used to effectively sample rare species. Lapilli otoliths (one of the three pair of ear stones found within the inner ear of fish) were removed from juvenile Alligator Gar collected in July of 2013. Daily ages were estimated by counting the number of rings present, and spawn dates were back-calculated from date of capture and subtracting 8 days (3 days from spawn to hatch and 5 days from hatch to swimup when the first ring forms). Alligator Gar daily age estimation ranged from 50 to 63 days old since swim-up. Spawn dates corresponded to rising pool elevations of Lake Texoma and water pulses of tributaries.

  17. Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer (United States)

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


    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.

  18. Structure refinement of flexible proteins using dipolar couplings: application to the protein p8MTCP1. (United States)

    Déméné, Hélène; Ducat, Thierry; Barthe, Philippe; Delsuc, Marc-André; Roumestand, Christian


    The present study deals with the relevance of using mobility-averaged dipolar couplings for the structure refinement of flexible proteins. The 68-residue protein p8MTCP1 has been chosen as model for this study. Its solution state consists mainly of three alpha-helices. The two N-terminal helices are strapped in a well-determined alpha-hairpin, whereas, due to an intrinsic mobility, the position of the third helix is less well defined in the NMR structure. To further characterize the degrees of freedom of this helix, we have measured the dipolar coupling constants in the backbone of p8MTCP1 in a bicellar medium. We show here that including D(dip)HN dipolar couplings in the structure calculation protocol improves the structure of the alpha-hairpin but not the positioning of the third helix. This is due to the motional averaging of the dipolar couplings measured in the last helix. Performing two calculations with different force constants for the dipolar restraints highlights the inconstancy of these mobility-averaged dipolar couplings. Alternatively, prior to any structure calculations, comparing the values of the dipolar couplings measured in helix III to values back-calculated from an ideal helix demonstrates that they are atypical for a helix. This can be partly attributed to mobility effects since the inclusion of the 15N relaxation derived order parameter allows for a better fit.

  19. Concentrations in ambient air and emissions of cyclic volatile methylsiloxanes in Zurich, Switzerland. (United States)

    Buser, Andreas M; Kierkegaard, Amelie; Bogdal, Christian; MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad


    Tens of thousands of tonnes of cyclic volatile methylsiloxanes (cVMS) are used each year globally, which leads to high and continuous cVMS emissions to air. However, field measurements of cVMS in air and empirical information about emission rates to air are still limited. Here we present measurements of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) in air for Zurich, Switzerland. The measurements were performed in January and February 2011 over a period of eight days and at two sites (city center and background) with a temporal resolution of 6-12 h. Concentrations of D5 and D6 are higher in the center of Zurich and range from 100 to 650 ng m(-3) and from 10 to 79 ng m(-3), respectively. These values are among the highest levels of D5 and D6 reported in the literature. In a second step, we used a multimedia environmental fate model parametrized for the region of Zurich to interpret the levels and time trends in the cVMS concentrations and to back-calculate the emission rates of D5 and D6 from the city of Zurich. The average emission rates obtained for D5 and D6 are 120 kg d(-1) and 14 kg d(-1), respectively, which corresponds to per-capita emissions of 310 mg capita(-1) d(-1) for D5 and 36 mg capita(-1) d(-1) for D6.

  20. Individual protein balance strongly influences delta15N and delta13C values in Nile tilapia, Oreochromis niloticus. (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 delta(15)N and delta(13)C values. An experiment using Nile tilapia [ Oreochromis niloticus (L.)] was therefore carried out to test the effect of different dietary protein contents (35.4, 42.3, and 50.9%) on delta(15)N and delta(13)C values of the whole tilapia. The fish were fed the isoenergetic and isolipidic semi-synthetic diets at a relatively low level. delta(15)N and delta(13)C values of the lipid-free body did not differ between the fish fed the diets with different protein contents, but the trophic shift for N and C isotopes decreased with increasing protein accretion in the individual fish, for N from 6.5 per thousand to 4 per thousand and for C in the lipid-free body from 4 per thousand to 2.5 per thousand. This is the first study showing the strong influence of the individual protein balance to the degree to which the isotopic signature of dietary protein was modified in tissue protein of fish. The extrapolation of the trophic level or the reconstruction of the diet of an animal from stable isotope ratios without knowledge of the individual physiological condition and the feeding rate may lead to erroneous results.

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

    Directory of Open Access Journals (Sweden)

    Pompei L.


    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.

  2. Age and growth of round gobies in Lake Huron: Implications for food web dynamics (United States)

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


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

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

    Directory of Open Access Journals (Sweden)

    Francis Massashi Kakuda


    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.

  4. 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)


    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

  5. Towards a numerical run-out model for quick-clay slides (United States)

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


    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

  6. Age, growth, and gonadal characteristics of adult bighead carp, Hypophthalmichthys nobilis, in the lower Missouri River (United States)

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


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

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

    Directory of Open Access Journals (Sweden)

    Eurípedes Vargas do Amaral


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

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

    KAUST Repository

    Zhang, Chen


    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.

  9. Testing the hypothesis that treatment can eliminate HIV: a nationwide, population-based study of the Danish HIV epidemic in men who have sex with men (United States)

    Okano, Justin T.; Robbins, Danielle; Palk, Laurence; Gerstoft, Jan; Obel, Niels; Blower, Sally


    Summary Background Worldwide, ~35 million individuals are infected with HIV; ~25 million in sub-Saharan Africa (SSA). The WHO proposes using “treatment as prevention” (TasP) to eliminate HIV. Treatment suppresses viral load, decreasing the probability an individual transmits HIV. The elimination threshold is one new HIV infection per 1,000 individuals. Here, we test the hypothesis that TasP can substantially reduce epidemics and eliminate HIV. We estimate the impact of TasP, between 1996–2013, on the Danish HIV epidemic in Men-who-have-Sex-with-Men (MSM), an epidemic UNAIDS has identified as a priority for elimination. Methods We use a CD4-staged Bayesian back-calculation approach to estimate incidence, and the “hidden epidemic” (the number of HIV-infected undiagnosed MSM). We use data from an ongoing nationwide population-based study: the Danish HIV Cohort Study. Findings Incidence, and the hidden epidemic, decreased substantially after treatment was introduced in 1996. By 2013, incidence was close to the elimination threshold: 1·4 (median, 95% Bayesian Credible Interval (BCI): 0·4–2·1) new HIV infections per 1,000 MSM. There were only 617 (median, 95% BCI: 264–858) undiagnosed MSM. Decreasing incidence and increasing treatment coverage are highly correlated; a threshold effect is apparent. Interpretation Our study is the first to show that TasP can substantially reduce a country’s HIV epidemic, and bring it close to elimination. However, we have shown the effectiveness of TasP under optimal conditions: very high treatment coverage, and exceptionally high (98%) viral suppression rate. Unless these extremely challenging conditions can be met in SSA, the WHO’s global elimination strategy is unlikely to succeed. Funding NIAID/NIH PMID:27174504

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

    Institute of Scientific and Technical Information of China (English)

    王忠波; 刘文珽; 贺小帆


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

  11. Fate of PBDEs in juvenile lake trout estimated using a dynamic multichemical fish model. (United States)

    Bhavsar, Satyendra P; Gandhi, Nilima; Gewurtz, Sarah B; Tomy, Gregg T


    Biotransformation half-lives (HL) and gut absorption efficiencies (GAE) of PBDE congeners in fish are poorly known and challenging to quantify experimentally. These values are needed in order to accurately assess their food web dynamics, and in turn, for policy development We recently developed a multichemical aquatic food web model, which was used to estimate HL of four PBDE congeners in a simple Arctic food web. However, an application of this model to more complex food webs would dramatically increase the uncertainties in the results due to the large number of unknowns that would need to be considered simultaneously. As such, an in-depth analysis of possible HL and GAE of additional PBDE congeners at the scale of individual fish species would facilitate model application to more complex food webs. For this purpose, we developed a fugacity-based dynamic multichemical fish model and applied it to previously published experimental laboratory data. The model was calibrated by maximizing correspondence between the modeled and observed concentrations for each of the thirteen congeners at two dietary concentrations in juvenile lake trout (Salvelinus namaycush) during uptake and depuration phases mainly by varying HL and GAE. A robust parametrization and calibration procedure gave us confidence in our back-calculated congener-specific HL of 42-420 days and GAE of 20-45%. These values can be used as a starting point for model applications to natural fish populations. The fate/transport results suggest that not only loss of PBDE congeners via degradation, but also input through biotransformation of higher brominated congeners, should be accounted for in order to accurately portray dynamics of PBDEs in fish.

  12. Population viability of Arctic grayling in the Gibbon River, Yellowstone National Park (United States)

    Steed, Amber C.; Zale, Alexander V.; Koel, Todd M.; Kalinowski, Steven T.


    The fluvial Arctic grayling Thymallus arcticus is restricted to less than 5% of its native range in the contiguous United States and was relisted as a category 3 candidate species under the U.S. Endangered Species Act in 2010. Although fluvial Arctic grayling of the lower Gibbon River, Yellowstone National Park, Wyoming, were considered to have been extirpated by 1935, anglers and biologists have continued to report catching low numbers of Arctic grayling in the river. Our goal was to determine whether a viable population of fluvial Arctic grayling persisted in the Gibbon River or whether the fish caught in the river were downstream emigrants from lacustrine populations in headwater lakes. We addressed this goal by determining relative abundances, sources, and evidence for successful spawning of Arctic grayling in the Gibbon River. During 2005 and 2006, Arctic grayling comprised between 0% and 3% of the salmonid catch in riverwide electrofishing (mean snorkeling (mean = 1%; SE = 1%) surveys; Arctic grayling constituted 0–14% of the salmonid catch obtained by targeted angling (3 of 22 fish; mean = 4%; SE = 5%). Low values of the genetic differentiation index (F ST = 0.0021 ± 0.002 [mean ± 95% confidence interval]) between headwater lake and river Arctic grayling indicated that fish from throughout the Gibbon River system probably belonged to the same population. Back-calculated lengths at most ages were similar among all fish, and successful spawning within the Gibbon River below the headwater lakes was not documented. Few Arctic grayling adults and no fry were detected in the Gibbon River, implying that a reproducing fluvial population does not exist there. These findings have implications for future Endangered Species Act considerations and management of fluvial Arctic grayling within and outside of Yellowstone National Park. Our comprehensive approach is broadly applicable to the management of sparsely detected aquatic species worldwide.

  13. Effect of deep injection on field-scale emissions of 1,3-dichloropropene and chloropicrin from bare soil (United States)

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


    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 <2%. Based on the five methods, deep injection reduced total emissions by approximately 2-24% compared to standard fumigation practices where fumigant injection is at 46 cm depth. Given the relatively wide range in emission-reduction percentages, a fumigant diffusion model was used to predict the percentage reduction in emissions by injecting at 61 cm, which yielded a 21% reduction in emissions. Significant reductions in emissions of 1,3-D and chloropicrin are possible by injecting soil fumigants deeper in soil.

  14. Partial migration in introduced wild chinook salmon (Oncorhynchus tshawytscha) of southern Chile (United States)

    Araya, Miguel; Niklitschek, Edwin J.; Secor, Dave H.; Piccoli, Philip M.


    Partial migration, the incidence of opposing migration behaviors within the same population, has been a key factor in the invasive ecology of Pacific salmon within South America. Here, we examined such life-cycle variation in of an introduced chinook salmon population in the Aysén watershed, one of the largest fjord systems in NW Patagonia. The chinook salmon is the most successful invasive salmonid species in Patagonia and has recently colonized numerous Patagonian watersheds of the Pacific and Atlantic Oceans. Using analyses of fish scales and otolith strontium:calcium ratios, our results suggest the presence of two distinct ecotypes in the chinook population, an ocean type and a stream type, in a 3:2 ratio. The distribution of back-calculated length at the time of emigration from river to marine habitats showed a mode of 14 cm for the ocean ecotype and 30 cm for the stream ecotype. River residence time for the ocean ecotype ranged from 1 to 10 months, while that of the stream ecotype varied between 14 and 20 months. Returning adults reproduced in riverine habitats between August and March, but reproduction by the stream ecotype was limited to the period between October and February. Our results show that exotic chinook salmon populations established in NW Patagonia present a diversity of life-history strategies, which seems to be as large as the ones exhibited by the species in its native distribution range and in other invaded ecosystems. Chinook salmon have successfully invaded most major rivers in Patagonia, placing priority on science and conservation related to their ecological impact.

  15. A limited contribution of Ca2+ current facilitation to paired-pulse facilitation of transmitter release at the rat calyx of Held. (United States)

    Müller, Martin; Felmy, Felix; Schneggenburger, Ralf


    Recent studies have suggested that transmitter release facilitation at synapses is largely mediated by presynaptic Ca(2+) current facilitation, but the exact contribution of Ca(2+) current facilitation has not been determined quantitatively. Here, we determine the contribution of Ca(2+) current facilitation, and of an increase in the residual free Ca(2+) concentration ([Ca(2+)](i)) in the nerve terminal, to paired-pulse facilitation of transmitter release at the calyx of Held. Under conditions of low release probability imposed by brief presynaptic voltage-clamp steps, transmitter release facilitation at short interstimulus intervals (4 ms) was 227 +/- 31% of control, Ca(2+) current facilitation was 113 +/- 4% of control, and the peak residual [Ca(2+)](i) was 252 +/- 18 nm over baseline. By inferring the 'local' [Ca(2+)](i) transients that drive transmitter release during these voltage-clamp stimuli with the help of a kinetic release model, we estimate that Ca(2+) current facilitation contributes to approximately 40% to paired-pulse facilitation of transmitter release. The remaining component of facilitation strongly depends on the build-up, and on the decay of the residual free [Ca(2+)](i), but cannot be explained by linear summation of the residual free [Ca(2+)](i), and the back-calculated 'local' [Ca(2+)](i) signal, which only accounts for approximately 10% of the total release facilitation. Further voltage-clamp experiments designed to compensate for Ca(2+) current facilitation demonstrated that about half of the observed transmitter release facilitation remains in the absence of Ca(2+) current facilitation. Our results indicate that paired-pulse facilitation of transmitter release at the calyx of Held is driven by at least two distinct mechanisms: Ca(2+) current facilitation, and a mechanism independent of Ca(2+) current facilitation that closely tracks the time course of residual free [Ca(2+)](i).

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

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


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

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

    KAUST Repository

    Li, Jianping


    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.

  18. Review on the epidemiology and dynamics of BSE epidemics. (United States)

    Ducrot, Christian; Arnold, Mark; de Koeijer, Aline; Heim, Dagmar; Calavas, Didier


    The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7, 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Europe. It confirmed that the clinical surveillance had a poor capacity to detect cases, and also showed the discrepancy of this passive surveillance efficiency between regions and production types (dairy/beef). Other risk factors for BSE were being in a dairy herd (three times more than beef), having a young age at first calving (for dairy cattle), being autumn-born (dairy and beef), and being in a herd with a very high milk yield. These findings focus the risk on the feeding regimen of calves/heifers. Several epidemiological studies across countries suggest that the feedborne source related to meat and bone meal (MBM) is the only substantiated route of infection - even after the feed ban -, while it is not possible to exclude maternal transmission or milk replacers as a source of some infections. In most European countries, the average age of the cases is increasing over time and the prevalence decreasing, which reflects the effectiveness of control measures. Consistent results on the trend of the epidemic were obtained using back-calculation modelling, the R(0) approach and Age-Period-Cohort models. Furthermore, active surveillance also resulted in the finding of atypical cases. These are distinct from previously found BSE and classified in two different forms based on biochemical characteristics; their prevalence is very low (36 cases up to 1st September 2007), affected animals were old and some of them displayed clinical signs. The origin and possibility of natural transmission is unknown.

  19. Quantitative interpretation of tracks for determination of body mass. (United States)

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


    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.

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

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


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

  1. Elasticity Modulus and Flexural Strength Assessment of Foam Concrete Layer of Poroflow (United States)

    Hajek, Matej; Decky, Martin; Drusa, Marian; Orininová, Lucia; Scherfel, Walter


    Nowadays, it is necessary to develop new building materials, which are in accordance to the principles of the following provisions of the Roads Act: The design of road is a subject that follows national technical standards, technical regulations and objectively established results of research and development for road infrastructure. Foam concrete, as a type of lightweight concrete, offers advantages such as low bulk density, thermal insulation and disadvantages that will be reduced by future development. The contribution focuses on identifying the major material characteristics of foam concrete named Poroflow 17-5, in order to replace cement-bound granular mixtures. The experimental measurements performed on test specimens were the subject of diploma thesis in 2015 and continuously of the dissertation thesis and grant research project. At the beginning of the contribution, an overview of the current use of foam concrete abroad is elaborated. Moreover, it aims to determine the flexural strength of test specimens Poroflow 17-5 in combination with various basis weights of the underlying geotextile. Another part of the article is devoted to back-calculation of indicative design modulus of Poroflow based layers based on the results of static plate load tests provided at in situ experimental stand of Faculty of Civil Engineering, University of Žilina (FCE Uniza). Testing stand has been created in order to solve problems related to research of road and railway structures. Concern to building construction presents a physical homomorphic model that is identical with the corresponding theory in all structural features. Based on the achieved material characteristics, the tensile strength in bending of previously used road construction materials was compared with innovative alternative of foam concrete and the suitability for the base layers of pavement roads was determined.

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

    Directory of Open Access Journals (Sweden)

    Michael G. Newbrey


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

  3. Age, Growth and Reproduction of Coryphaena hippurus (Linnaeus, 1758 in Maltese Waters, Central Mediterranean

    Directory of Open Access Journals (Sweden)

    M. GATT


    Full Text Available Age, growth and reproduction of the dolphinfish Coryphaena hippurus Linnaeus, 1758 collected from the Central Mediterranean in the period 2004-2010 by the traditional Maltese fish aggregating devices (FAD and surface longline fisheries were studied. The a and b parameters of the length-weight relationship for fish 11-142 cm fork length (FL (n = 4042 were determined as a = 0.018 and 0.022 with b = 2.85 and 2.79, for males and females respectively. The counting of annual increments from dorsal spines of >65 cm FL dolphinfish at X25 magnification (n = 47 permitting an age reading resolution in years  , and the counting of daily increments from sagittal otoliths of <65 cm FL dolphinfish at X400 magnification (n = 583 permitting an age reading resolution in days, were estimated; the von Bertalanffy growth model applied to these fish gave the following parameters: L∞ = 107.8 cm FL and 120.2 cm FL, and K = 1.9 yr-1 and 1.56 yr-1, for males and females respectively. The maximum age observed was 2 years. Size at 50% maturity for fish 10-131 cm FL (n = 1376 was 58.9 cm FL and 62.5 cm FL for males and females, respectively. The sex ratio for the fish sampled from the FAD fishery (10.5-131 cm FL was 1:1.54 (M:F and for dolphinfish sampled from the surface longline fishery (91-130 cm FL was 1:0.76 (M:F.  Back-calculated hatch dates from age-0 dolphinfish (n = 518 suggested that spawning occurs from June to September with the highest levels in June. This study is the first to use dorsal spines to determine the age of adult dolphinfish.

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

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    Blaz Stres

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

  5. Emissions of polybrominated diphenyl ethers (PBDEs) in Zurich, Switzerland, determined by a combination of measurements and modeling. (United States)

    Bogdal, Christian; Wang, Zhanyun; Buser, Andreas M; Scheringer, Martin; Gerecke, Andreas C; Schmid, Peter; Müller, Claudia E; MacLeod, Matthew; Hungerbühler, Konrad


    Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants but they are of concern and are currently being phased-out because of their environmentally hazardous properties and their potential to cause adverse health effects. We analyzed PBDEs in Zurich, Switzerland, and applied a multi-media environmental fate model to back-calculate the rate of PBDE emission to air. PBDE concentrations in ambient air were measured in summer 2010 and winter 2011 in the city center of Zurich. Concentrations were higher in summer (sum PBDEs 118-591 pg m(-3)) than in winter (sum PBDEs 17-151 pg m(-3)), and are on the upper end of concentrations reported in literature for urban sites with no point sources of PBDEs. The emissions derived from our measurements (summer: 53-165 μg capita(-1) d(-1), winter: 25-112 μg capita(-1) d(-1)) and extrapolated to annual emissions for Switzerland (114-406 kg a(-1)) lie in the middle of ranges reported on the basis of substance flow analyses and emission inventories. The difference between summer and winter emissions is small compared to the difference that would be expected from the temperature dependence of PBDE vapor pressure, which would be consistent with emissions occurring to a large extent from flame-proofed materials located indoors under nearly constant temperature conditions and/or emissions to air occurring by suspension of particles containing PBDEs. Compared to previous studies in Switzerland, concentrations and emissions of PBDEs appear to have increased during the last five years with an increasing contribution of decabromodiphenyl ether, despite the addition of PBDEs to national and international regulations.

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

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    Justin Douglas Yeakel


    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

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

    Institute of Scientific and Technical Information of China (English)

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


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

  8. Sub-annual variability in historical water source use by Mediterranean riparian trees. (United States)

    Sargeant, Christopher; Singer, Michael


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

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

    Directory of Open Access Journals (Sweden)

    J. B. Heffernan


    Full Text Available 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 relationships between O2 and δ15NNO3 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 δ15NNO3 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.

  10. HIV Trends in the United States: Diagnoses and Estimated Incidence (United States)

    Song, Ruiguang; Tang, Tian; An, Qian; Prejean, Joseph; Dietz, Patricia; Hernandez, Angela L; Green, Timothy; Harris, Norma; McCray, Eugene; Mermin, Jonathan


    Background The best indicator of the impact of human immunodeficiency virus (HIV) prevention programs is the incidence of infection; however, HIV is a chronic infection and HIV diagnoses may include infections that occurred years before diagnosis. Alternative methods to estimate incidence use diagnoses, stage of disease, and laboratory assays of infection recency. Using a consistent, accurate method would allow for timely interpretation of HIV trends. Objective The objective of our study was to assess the recent progress toward reducing HIV infections in the United States overall and among selected population segments with available incidence estimation methods. Methods Data on cases of HIV infection reported to national surveillance for 2008-2013 were used to compare trends in HIV diagnoses, unadjusted and adjusted for reporting delay, and model-based incidence for the US population aged ≥13 years. Incidence was estimated using a biomarker for recency of infection (stratified extrapolation approach) and 2 back-calculation models (CD4 and Bayesian hierarchical models). HIV testing trends were determined from behavioral surveys for persons aged ≥18 years. Analyses were stratified by sex, race or ethnicity (black, Hispanic or Latino, and white), and transmission category (men who have sex with men, MSM). Results On average, HIV diagnoses decreased 4.0% per year from 48,309 in 2008 to 39,270 in 2013 (P<.001). Adjusting for reporting delays, diagnoses decreased 3.1% per year (P<.001). The CD4 model estimated an annual decrease in incidence of 4.6% (P<.001) and the Bayesian hierarchical model 2.6% (P<.001); the stratified extrapolation approach estimated a stable incidence. During these years, overall, the percentage of persons who ever had received an HIV test or had had a test within the past year remained stable; among MSM testing increased. For women, all 3 incidence models corroborated the decreasing trend in HIV diagnoses, and HIV diagnoses and 2 incidence

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

    Directory of Open Access Journals (Sweden)

    Guillermo Moyano


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

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

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


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

  13. 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.


    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

  14. Advanced Numerical Model for Irradiated Concrete

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  15. Validation of ELISA for the determination of anti-ricin immunoglobulin G concentration in mouse sera. (United States)

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


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

  16. Vibrational-rotational spectra of GaF and global multi-isotopologue analysis (United States)

    Uehara, Hiromichi; Horiai, Koui; Katsuie, Shunsuke


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

  17. 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)


    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)

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

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    Mirjam Kretzschmar


    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

  19. Emerging insights into the dynamics of submarine debris flows

    Directory of Open Access Journals (Sweden)

    A. Elverhøi


    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

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

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


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

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

    Directory of Open Access Journals (Sweden)



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

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

    Pastorello, Roberta; D'Agostino, Vincenzo


    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

  3. Emerging insights into the dynamics of submarine debris flows (United States)

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


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

  4. 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

  5. The evolution of the prevalence of classical scrapie in sheep in Great Britain using surveillance data between 2005 and 2012. (United States)

    Arnold, Mark; Ortiz-Pelaez, Angel


    After the decline of the Bovine Spongiform Encephalopathy (BSE) epidemic in Great Britain (GB), scrapie remains the most prevalent animal Transmissible Spongiform Encephalopathy (TSE) present in GB. A number of control measures have been implemented for classical scrapie, and since 2005 there has been a large reduction in the number of observed cases. The objective of this study is to estimate two measures of disease frequency using up to date surveillance data collected during and after the implementation of different control measures established since 2004, and breeding for resistance schemes that ran from 2001 until 2009. This would enable an assessment of the effectiveness of both the breeding for resistance programme and the compulsory eradication measures in reducing the prevalence of scrapie in GB. Evaluation of the sensitivity of the rapid post-mortem test for scrapie indicated that it detected scrapie in the last 25% of the incubation period. A back-calculation model was developed to estimate the prevalence of infection at animal and flock-level. The results of the model indicated a mean drop of infection prevalence of 31% each year, leading to a 90% drop in infection prevalence between 2005, with an estimate of 5737 infected sheep in GB in 2012. The risks of classical scrapie infection in animals with genotypes of National Scrapie Plan Types I-IV (all other genotypes), relative to Type V (all genotypes containing V136 R154 Q171 and not A136 R154 R171), were estimated to be: 0, 0.0008, 0.07, and 0.21 respectively. The model estimated a very low rate of reporting of clinical suspects and a large decline from 2007 of the probability of a sheep being reported as a clinical suspect. The model also estimated that the expected number of sheep holdings with classical scrapie in 2012 was 215 (95% confidence interval: 33-437), out of a total of approximately 72,000 sheep holdings in GB. Model estimates indicate that the prevalence in 2012 has dropped to 10% of that

  6. Workability Indicator for Emulsified Asphalt Recycled Mixture and Influence Factors%乳化沥青冷再生混合料和易性指标及影响因素

    Institute of Scientific and Technical Information of China (English)

    汪德才; 郝培文; 刘娜; 张海伟; 李志刚


    In order to study the workability of emulsified asphalt cold recycled mixture ( ECRM ) , the different characteristics of emulsified asphalt, reclaimed asphalt pavement ( RAP ) content and the influence laws of mixing water content were researched with the self-developed workability test equipment. Moreover, the significance level of influence factors was analyzed by statistic methods. Finally,the rationality of this method and the indicator was verified by back-calculating the jelling time and the volume parameter of superpave gyratory compactor ( SGC) molding method. The result shows that the workability of ECRM become worse with increasing RAP content, which can be siginificantly improved by proper mixing water content. RAP content and mixing water content have a significantly impacts on the workability,while the emulsified asphalt has no such effects. ECRM has the optimal timing of the compaction after mixing, when the torque threshold is recommended for 20 N·m.%为了研究乳化沥青冷再生混合料和易性,采用自主研发的和易性测试设备,以扭矩值作为乳化沥青冷再生混合料和易性表征指标,研究了不同特性的乳化沥青、回收沥青路面材料( reclaimed asphalt pavement,RAP)掺量及拌和用水量对乳化沥青冷再生混合料和易性的影响规律,分析了乳化沥青冷再生混合料和易性影响因素的显著性,并通过反算水泥初凝时间以及旋转压实成型试件的体积参数是否在规范范围验证了测试方法及指标的合理性.结果表明:再生混合料和易性随着RAP掺量的增加而变差,合适的拌和用水量能显著改善再生混合料和易性;RAP掺量和拌和用水量对再生混合料和易性有显著影响,而乳化沥青特性的影响不明显;乳化沥青冷再生混合料在拌和后存在一个最佳压实时机,推荐扭矩阈值为20 N·m.

  7. Expanding our understanding of the trade in marine aquarium animals (United States)

    Tlusty, Michael F.; Szczebak, Joseph T.; Holmberg, Robert J.


    6.9 million individuals) and invertebrates (4.2, 3.7, and 3.6 million individuals) assessed by analyzing the invoice data are roughly 60% of the total volumes recorded through the Law Enforcement Management Information System (LEMIS) dataset. Using these complete years, we back-calculated the number of individuals of both fishes and invertebrates imported in 2000, 2004, and 2005. These estimates (9.3, 10.8, and 11.2 million individual fish per year) were consistent with the three years of complete data. We also use these data to understand the global trade in two species (Banggai cardinalfish, Pterapogon kauderni, and orange clownfish, Amphiprion ocellaris / percula) recently considered for Endangered Species Act listing. can help create more effective management plans for the traded species, and ideally could be implemented at key trade ports to better assess the global trade of aquatic wildlife. PMID:28149703

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

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


    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

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

    Institute of Scientific and Technical Information of China (English)

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


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

  10. Expanding our understanding of the trade in marine aquarium animals

    Directory of Open Access Journals (Sweden)

    Andrew L. Rhyne


    fish (8.2, 7.3, and 6.9 million individuals and invertebrates (4.2, 3.7, and 3.6 million individuals assessed by analyzing the invoice data are roughly 60% of the total volumes recorded through the Law Enforcement Management Information System (LEMIS dataset. Using these complete years, we back-calculated the number of individuals of both fishes and invertebrates imported in 2000, 2004, and 2005. These estimates (9.3, 10.8, and 11.2 million individual fish per year were consistent with the three years of complete data. We also use these data to understand the global trade in two species (Banggai cardinalfish, Pterapogon kauderni, and orange clownfish, Amphiprion ocellaris / percula recently considered for Endangered Species Act listing. can help create more effective management plans for the traded species, and ideally could be implemented at key trade ports to better assess the global trade of aquatic wildlife.

  11. An integrated multi-scale risk analysis procedure for pluvial flooding (United States)

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


    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.

  12. Quantifying moisture transport in cementitious materials using neutron radiography (United States)

    Lucero, Catherine L.

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

  13. Characteristics and simulation of the canopy conductance of Hippophae rhamnoides in Qaidam Region of northwestern China%柴达木地区沙棘冠层导度特征及模拟

    Institute of Scientific and Technical Information of China (English)

    王辉; 贺康宁; 徐特; 刘玉娟; 刘颖; 张雪


    为了揭示沙棘冠层导度对环境因子的响应规律,评价Jarvis模型在沙棘冠层尺度上的适用性,利用Granier热消散式探针连续测定了青海省柴达木盆地实验站内的沙棘灌丛树干液流,并同步观测气象因子,利用 Penman-Monteith方程反推方法,获得了长期连续的冠层导度。在分析沙棘冠层导度动态变化规律的基础上,采用十字交叉法对Jarvis模型进行参数率定和误差分析。结果表明:研究区沙棘冠层导度日变化呈“单峰型”曲线,冠层导度随饱和水汽压差的增加呈负指数关系下降,并与太阳辐射强度呈正相关。基于饱和水汽压差、太阳辐射强度和气温这3个环境变量的Jarvis模型可解释gc变化的81%,且最低相对误差仅11.01%。环境因子对冠层导度( gc )模型精度的影响依次为饱和水汽压差(ⅤPD)>太阳辐射强度( Rs )>气温( T)。%The aim of this study was to explain the response of canopy conductance of sea buckthorn ( Hippophae rhamnoides ) to different environmental conditions so as to evaluate the feasibility of application of Jarvis model in sea buckthorn at the canopy scale. By using Granier’ s thermal dissipation probe, the sap flow of sea buckthorn in Qaidam Basin in Qinghai Province, northwestern China was continuously measured,and as well,the environmental factors such as incoming solar radiation intensity (Rs), air temperature (T), relative humidity (RH), wind speed (u) and rainfall were synchronically measured. Based on sap flow, canopy conductance ( gc ) was continuously simulated by back-calculated Penman-Monteith model. By analysis of gc of sea buckthorn, Jarvis stomatal model was simulated and analyzed with cross-validation. The results indicated that the diurnal variation in canopy conductance of sea buckthorn showed a single-peaked curve. There was a negative logarithm relationship between canopy conductance and vapor pressure deficit (ⅤPD ) under

  14. 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.)


    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

  15. Combined statistical analysis of landslide release and propagation (United States)

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


    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

  16. Oxidation resistance, thermal conductivity, and spectral emittance of fully dense zirconium diboride with silicon carbide and tantalum diboride additives (United States)

    Van Laningham, Gregg Thomas

    temperature were back-calculated from the experimental results for the multi-phase materials, and literature thermal conductivities of the other two phases. This established a relatively constant thermal conductivity of 88-104 W·K over the evaluated temperature range. Further heat transport characterization was performed using pre-oxidized, directly resistively heated ZrB2-30 mol% SiC ribbon specimens under the observation of a spectral radiometer. The ribbons were heated and held at specific temperatures over the range 1100-1330°C in flowing Ar, and normal spectral emittance values were recorded over the 1-6 μm range with a resolution of 10 nm. The normal spectral emittance was shown to decrease with loss of the borosilicate layer over the course of the data collection time periods. This change was measured and compensated for to produce traces showing the emittance of the oxidized composition rising from ~0.7 to ~0.9 over the range of wavelengths measured (1-6 μm).

  17. Characterization of estuary use by Nisqually Hatchery Chinook based on Otolith analysis (United States)

    Lind-Null, Angie M.; Larsen, Kim A.; Reisenbichler, Reg


    INTRODUCTION The Nisqually Fall Chinook population is one of 27 stocks in the Puget Sound evolutionarily significant unit listed as threatened under the federal Endangered Species Act (ESA). Preservation and extensive restoration of the Nisqually delta ecosystem are planned to assist in recovery of the stock. A pre-restoration baseline including life history types, estuary residence time, growth rates, and habitat use are needed to evaluate the potential response of hatchery and wild Chinook salmon to restoration. Otolith analysis has been selected as a means to examine Chinook salmon life history, growth, and residence in the Nisqually estuary. Over time, the information from the otolith analyses will be used to: 1) determine if estuary restoration actions cause changes to the population structure (i.e. frequency of the different life history trajectories) for Nisqually River Chinook, 2) compare pre- and post- restoration residence times and growth rates, 3) suggest whether estuary restoration yields substantial benefits for Chinook salmon through (1) and (2), and 4) compare differences in habitat use between hatchery and wild Chinook to further protect ESA listed stock. Otoliths are calcium carbonate structures in the inner ear that grow in proportion to the overall growth of the fish. Daily growth increments can be measured so date and fish size at various habitat transitions can be back-calculated. Careful analysis of otolith microstructure can be used to determine the number of days that a fish resided in the estuary as a juvenile (increment counts), size at entrance to the estuary, size at egress, and the amount that the fish grew while in the estuary. Juvenile hatchery Chinook salmon are generally released as smolts that move quickly through the delta with much shorter residence times than for many wild fish and are not dependent on the delta as nursery habitat (Myers and Horton 1982; Mace 1983; Levings et al. 1986). The purpose of this study is to use and

  18. Pre-Restoration Habitat Use by Chinook Salmon in the Nisqually Estuary Using Otolith Analysis (United States)

    Lind-Null, Angela; Larsen, Kimberly; Reisenbichler, Reginald


    INTRODUCTION The Nisqually Fall Chinook population is one of 27 stocks in the Puget Sound evolutionarily significant unit listed as threatened under the federal Endangered Species Act. The preservation of the Nisqually delta ecosystem coupled with extensive restoration of approximately 1,000 acres of diked estuarine habitat is identified as the highest priority action for the recovery of naturally spawning Nisqually River Fall Chinook salmon (Oncorhynchus tshawytscha) in the Nisqually Chinook Recovery Plan. In order to evaluate the response of Chinook salmon to restoration, a pre-restoration baseline of life history diversity and estuary utilization must be established. Otolith analysis has been proposed as a means to measure Chinook salmon life history diversity, growth, and residence in the Nisqually estuary. Over time, the information from the otolith analyses will be used to: (1) determine if estuary restoration actions cause changes to the population structure (i.e. frequency of the different life history trajectories) for Nisqually River Chinook, (2) compare pre and post restoration residence times and growth rates, and (3) suggest whether estuary restoration yields substantial benefits for Chinook salmon. Otoliths are calcium carbonate structures in the inner ear that grow in proportion to the overall growth of the fish. Daily growth increments can be measured so date and fish size at various habitat transitions can be back-calculated. Careful analysis of otolith microstructure can be used to determine the number of days that a fish resided in the estuary as a juvenile (increment counts), size at entrance to the estuary, size at egress, and the amount that the fish grew while in the estuary. Juvenile Chinook salmon can exhibit a variety of life history trajectories ? some enter the sea (or Puget Sound) as fry, some rear in the estuary before entering the sea, and some rear in the river and then move rapidly through the estuary into the sea as smolts. The

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

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


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

  20. Effects of surface applications of biosolids on soil, crops, ground water, and streambed sediment near Deer Trail, Colorado, 1999-2003 (United States)

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


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

  1. 农村土地承包经营权调查中面积精度问题分析%Area accuracy analysis for investigation of rural land contractual management right

    Institute of Scientific and Technical Information of China (English)

    赵虎; 裴志远


    account the terrain type (plain and mountain area). We also evaluated the influence of 3 different survey methods under different conditions, for example, various shape (the ratio of length to width changed from 1 to 10) or area size (from 0 to 12 hm2). Finally, the area lower limit of land parcel by using different methods was calculated and analyzed from a practical view. We did back-calculation works based on the mathematical formula describing the relationship between land parcel area and the land shape, area relative error and mean square error of boundary point. Different area lower limits were presented by considering various land shape and error of boundary point. The imagery of the Second National Land Survey was also analyzed for its applicability in the investigation of the right of rural land contractual management. The results showed that:1) Theoretically, the relative area accuracy was mainly influenced by the mean square error of boundary point, the area of the land parcel and the shape of the land (ratio of length to width). The influences of the number and distribution of boundary points on the relative area accuracy were insignificant for the strict setting rules of the boundary points. From the operational view, the appropriate increase of the number of the boundary points would greatly improve the area accuracy in the land survey;2) Only considering to keep the relative area accuracy within a reasonable range, the analytic (surveying with global position system-real time kinematic, GPS-RTK) method was generally applicable over all regions of the whole country. Imagery with the scale no less than 1:1000 could be applied for most of the southern region with the ratio of length to width being equal to 2, and for most of the northern region with the ratio of length to width equaling 9, the imagery scale should be no less than 1:2000;3) To carry out the rural land parcel contractual management survey with “the Second National Land Survey” images with a

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

    Janu, Stefan; Mehlhorn, Susanne; Moser, Markus


    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


    Institute of Scientific and Technical Information of China (English)

    向建国; 向劲; 王星璐; 李钟杰; 谢松光


    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.