Jurgens, Bryant; Bohlke, John Karl; Kauffman, Leon J.; Belitz, Kenneth; Esser, Bradley K.
2016-01-01
A partial exponential lumped parameter model (PEM) was derived to determine age distributions and nitrate trends in long-screened production wells. The PEM can simulate age distributions for wells screened over any finite interval of an aquifer that has an exponential distribution of age with depth. The PEM has 3 parameters – the ratio of saturated thickness to the top and bottom of the screen and mean age, but these can be reduced to 1 parameter (mean age) by using well construction information and estimates of the saturated thickness. The PEM was tested with data from 30 production wells in a heterogeneous alluvial fan aquifer in California, USA. Well construction data were used to guide parameterization of a PEM for each well and mean age was calibrated to measured environmental tracer data (3H, 3He, CFC-113, and 14C). Results were compared to age distributions generated for individual wells using advective particle tracking models (PTMs). Age distributions from PTMs were more complex than PEM distributions, but PEMs provided better fits to tracer data, partly because the PTMs did not simulate 14C accurately in wells that captured varying amounts of old groundwater recharged at lower rates prior to groundwater development and irrigation. Nitrate trends were simulated independently of the calibration process and the PEM provided good fits for at least 11 of 24 wells. This work shows that the PEM, and lumped parameter models (LPMs) in general, can often identify critical features of the age distributions in wells that are needed to explain observed tracer data and nonpoint source contaminant trends, even in systems where aquifer heterogeneity and water-use complicate distributions of age. While accurate PTMs are preferable for understanding and predicting aquifer-scale responses to water use and contaminant transport, LPMs can be sensitive to local conditions near individual wells that may be inaccurately represented or missing in an aquifer-scale flow model.
Engdahl, Nicholas B.; Ginn, Timothy R.; Fogg, Graham E.
2015-01-01
Groundwater age distributions are used to estimate the parameters of Fickian, and non-Fickian, effective models of solute transport. Based on the similarities between the transport and age equations, we develop a deconvolution based approach that describes transport between two monitoring wells. We show that the proposed method gives exact estimates of the travel time distribution between two wells when the domain is stationary and that the method still provides useful information on transport when the domain is non-stationary. The method is demonstrated using idealized uniform and layered 2-D aquifers. Homogeneous transport is determined exactly and non-Fickian transport in a layered aquifer was also approximated very well, even though this example problem is shown to be scale-dependent. This work introduces a method that addresses a significant limitation of tracer tests and non-Fickian transport modeling which is the difficulty in determining the effective parameters of the transport model. PMID:25821342
Filippazzo, Joseph C.; Rice, Emily L.; Faherty, Jacqueline; Cruz, Kelle L.; Van Gordon, Mollie M.; Looper, Dagny L.
2015-09-10
We combine optical, near-infrared, and mid-infrared spectra and photometry to construct expanded spectral energy distributions for 145 field age (>500 Myr) and 53 young (lower age estimate <500 Myr) ultracool dwarfs (M6-T9). This range of spectral types includes very low mass stars, brown dwarfs, and planetary mass objects, providing fundamental parameters across both the hydrogen and deuterium burning minimum masses for the largest sample assembled to date. A subsample of 29 objects have well constrained ages as probable members of a nearby young moving group. We use 182 parallaxes and 16 kinematic distances to determine precise bolometric luminosities (L{sub bol}) and radius estimates from evolutionary models give semi-empirical effective temperatures (T{sub eff}) for the full range of young and field age late-M, L, and T dwarfs. We construct age-sensitive relationships of luminosity, temperature, and absolute magnitude as functions of spectral type and absolute magnitude to disentangle the effects of degenerate physical parameters such as T{sub eff}, surface gravity, and clouds on spectral morphology. We report bolometric corrections in J for both field age and young objects and find differences of up to a magnitude for late-L dwarfs. Our correction in Ks shows a larger dispersion but not necessarily a different relationship for young and field age sequences. We also characterize the NIR–MIR reddening of low gravity L dwarfs and identify a systematically cooler T{sub eff} of up to 300 K from field age objects of the same spectral type and 400 K cooler from field age objects of the same M{sub H} magnitude.
Age Distribution of Groundwater
NASA Astrophysics Data System (ADS)
Morgenstern, U.; Daughney, C. J.
2012-04-01
Groundwater at the discharge point comprises a mixture of water from different flow lines with different travel time and therefore has no discrete age but an age distribution. The age distribution can be assessed by measuring how a pulse shaped tracer moves through the groundwater system. Detection of the time delay and the dispersion of the peak in the groundwater compared to the tracer input reveals the mean residence time and the mixing parameter. Tritium from nuclear weapons testing in the early 1960s resulted in a peak-shaped tritium input to the whole hydrologic system on earth. Tritium is the ideal tracer for groundwater because it is an isotope of hydrogen and therefore is part of the water molecule. Tritium time series data that encompass the passage of the bomb tritium pulse through the groundwater system in all common hydrogeologic situations in New Zealand demonstrate a semi-systematic pattern between age distribution parameters and hydrologic situation. The data in general indicate high fraction of mixing, but in some cases also indicate high piston flow. We will show that still, 45 years after the peak of the bomb tritium, it is possible to assess accurately the parameters of age distributions by measuring the tail of the bomb tritium.
NASA Astrophysics Data System (ADS)
Filippazzo, Joe; Rice, Emily L.; Faherty, Jacqueline K.; Cruz, Kelle L.; Godfrey, Paige A.; BDNYC
2016-01-01
The physical and atmospheric properties of ultracool dwarfs are deeply entangled due to the degenerate effects of mass, age, metallicity, clouds and dust, activity, rotation, and possibly even formation mechanism on observed spectra. Accurate determination of fundamental parameters for a wide diversity of objects at the low end of the IMF is thus crucial to testing stellar and planetary formation theories. To determine these quantities, we constructed and flux calibrated nearly-complete spectral energy distributions (SEDs) for 221 M, L, T, and Y dwarfs using published parallaxes and 0.3-40 μm spectra and photometry. From these homogeneous SEDs, we calculated bolometric luminosity (Lbol), effective temperature (Teff), mass, surface gravity, radius, spectral indexes, synthetic photometry, and bolometric corrections (BCs) for each object. We used these results to derive Lbol, Teff, and BC polynomial relations across the entire very-low-mass star/brown dwarf/planetary mass regime. We use a subsample of objects with age constraints based on nearby young moving group membership, companionship with a young star, or spectral signatures of low surface gravity to define new age-sensitive diagnostics and characterize the reddening of young substellar atmospheres as a redistribution of flux from the near-infrared into the mid-infrared. Consequently we find the SED flux pivots at Ks band, making BCKs as a function of spectral type a tight and age independent relationship. We find that young L dwarfs are systematically 300 K cooler than field age objects of the same spectral type and up to 600 K cooler than field age objects of the same absolute H magnitude. Finally, we present preliminary comparisons of these empirical results to best fit parameters from four different model atmosphere grids via Markov-Chain Monte Carlo analysis in order to create prescriptions for the reliable and efficient characterization of new ultracool dwarfs.
Eberts, S.M.; Böhlke, J.K.; Kauffman, L.J.; Jurgens, B.C.
2012-01-01
Environmental age tracers have been used in various ways to help assess vulnerability of drinking-water production wells to contamination. The most appropriate approach will depend on the information that is available and that which is desired. To understand how the well will respond to changing nonpoint-source contaminant inputs at the water table, some representation of the distribution of groundwater ages in the well is needed. Such information for production wells is sparse and difficult to obtain, especially in areas lacking detailed field studies. In this study, age distributions derived from detailed groundwater-flow models with advective particle tracking were compared with those generated from lumped-parameter models to examine conditions in which estimates from simpler, less resource-intensive lumped-parameter models could be used in place of estimates from particle-tracking models. In each of four contrasting hydrogeologic settings in the USA, particle-tracking and lumped-parameter models yielded roughly similar age distributions and largely indistinguishable contaminant trends when based on similar conceptual models and calibrated to similar tracer data. Although model calibrations and predictions were variably affected by tracer limitations and conceptual ambiguities, results illustrated the importance of full age distributions, rather than apparent tracer ages or model mean ages, for trend analysis and forecasting.
NASA Astrophysics Data System (ADS)
Jurgens, B. C.; Bohlke, J. K.; Voss, S.; Fram, M. S.; Esser, B.
2015-12-01
Tracer-based, lumped parameter models (LPMs) are an appealing way to estimate the distribution of age for groundwater because the cost of sampling wells is often less than building numerical groundwater flow models sufficiently complex to provide groundwater age distributions. In practice, however, tracer datasets are often incomplete because of anthropogenic or terrigenic contamination of tracers, or analytical limitations. While age interpretations using such datsets can have large uncertainties, it may still be possible to identify key parts of the age distribution if LPMs are carefully chosen to match hydrogeologic conceptualization and the degree of age mixing is reasonably estimated. We developed a systematic approach for evaluating groundwater age distributions using LPMs with a large but incomplete set of tracer data (3H, 3Hetrit, 14C, and CFCs) from 535 wells, mostly used for public supply, in the Central Valley, California, USA that were sampled by the USGS for the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment or the USGS National Water Quality Assessment Programs. In addition to mean ages, LPMs gave estimates of unsaturated zone travel times, recharge rates for pre- and post-development groundwater, the degree of age mixing in wells, proportion of young water (<60 yrs), and the depth of the boundary between post-development and predevelopment groundwater throughout the Central Valley. Age interpretations were evaluated by comparing past nitrate trends with LPM predicted trends, and whether the presence or absence of anthropogenic organic compounds was consistent with model results. This study illustrates a practical approach for assessing groundwater age information at a large scale to reveal important characteristics about the age structure of a major aquifer, and of the water supplies being derived from it.
NASA Astrophysics Data System (ADS)
Jurgens, B. C.; Bohlke, J. K.; Kauffman, L. J.; Belitz, K.
2013-12-01
Age distributions for 30 production wells (mostly public-supply) were determined using two methods: 1) calibration of age tracer data with lumped parameter models (LPMs) and 2) by advective particle tracking (PT) simulations using MODPATH and a regional steady-state groundwater flow model. The LPMs were calibrated with measurements of 3H, 3He(trit), and 14C by minimizing the Chi-square test statistic using a non-linear solver. A partial exponential model (PEM) was the primary LPM used in this study and a combination of two PEMs were used in cases where binary age mixtures were identified. The PEM is a reformulated version of the exponential model that is parameterized to simulate the age distribution in a well that is screened over any finite interval within the aquifer. The regional numerical model was calibrated to water-levels and gradients, and simulated PT age tracer concentrations were calibrated to the MODPATH porosity value. Age distributions were then used to predict nitrate concentrations in wells using agricultural application rates of nitrate in the central eastside of the San Joaquin Valley, California. Both methods showed that wells in the study area captured groundwater with a broad range of ages, spanning decades to millennia. Age distributions from the LPMs predicted age tracer and nitrate concentrations more accurately than the regional PT simulation; whereas PT simulations incorporating more detailed information about water-levels and hydraulic gradients near wells also provided good fits. 14C concentrations were not simulated well by the regional steady-state model, especially for wells with a significant fraction of old groundwater, because the model simulates the current, perturbed system and does not simulate recharge rates and velocities of the predevelopment system. Results from the LPMs yielded an average recharge rate of 0.55 m/yr, which was similar to the average recharge rate of 0.54 m/yr determined from a water budget analysis for the
Contado, Catia; Vighi, Eleonora; Dalpiaz, Alessandro; Leo, Eliana
2013-01-01
Poly(lactic-co-glycolic acid) particles in the 200-400-nm size range were formulated through nanoprecipitation and solvent evaporation methods. Different concentrations of the polymer and stabilizer (Pluronic® F 68) were tested in order to identify the best conditions for making poly(lactic-co-glycolic acid) particles of suitable size, stable in time, and to be used as carriers for brain-targeting drugs. The particles with the best characteristics for delivery system design were those formulated by nanoprecipitation with an organic/water phase ratio of 2:30, a polymer concentration of 25 mg/mL, and a surfactant concentration of 0.83 mg/mL; their surface charge was reasonably negative (approximately -27 mV) and the average size of the almost monodisperse population was roughly 250 nm. Particle characterization was obtained through ζ-potential measurements, scanning electron microscope observations, and particle size distribution determinations; the latter achieved by both photon-correlation spectroscopy and sedimentation field flow fractionation. Sedimentation field flow fractionation, which is considered more reliable than photon-correlation spectroscopy in describing the possible particle size distribution modifications, was used to investigate the effects of 3 months of storage at 4 °C had on the lyophilized particles. Figure Particle size ditribution from the SdFFF and the PCS techniques.
Modeled ground water age distributions
Woolfenden, Linda R.; Ginn, Timothy R.
2009-01-01
The age of ground water in any given sample is a distributed quantity representing distributed provenance (in space and time) of the water. Conventional analysis of tracers such as unstable isotopes or anthropogenic chemical species gives discrete or binary measures of the presence of water of a given age. Modeled ground water age distributions provide a continuous measure of contributions from different recharge sources to aquifers. A numerical solution of the ground water age equation of Ginn (1999) was tested both on a hypothetical simplified one-dimensional flow system and under real world conditions. Results from these simulations yield the first continuous distributions of ground water age using this model. Complete age distributions as a function of one and two space dimensions were obtained from both numerical experiments. Simulations in the test problem produced mean ages that were consistent with the expected value at the end of the model domain for all dispersivity values tested, although the mean ages for the two highest dispersivity values deviated slightly from the expected value. Mean ages in the dispersionless case also were consistent with the expected mean ages throughout the physical model domain. Simulations under real world conditions for three dispersivity values resulted in decreasing mean age with increasing dispersivity. This likely is a consequence of an edge effect. However, simulations for all three dispersivity values tested were mass balanced and stable demonstrating that the solution of the ground water age equation can provide estimates of water mass density distributions over age under real world conditions.
NASA Astrophysics Data System (ADS)
Jaureguizar, Andres J.; Ruarte, Claudio; Guerrero, Raúl A.
2006-03-01
The age-class distribution of the striped weakfish ( Cynoscion guatucupa) and its relationship with environmental factors were evaluated along the coast between Argentina and Uruguay, including the Río de la Plata estuary (36° S, 56° W). One hundred and seven stations were sampled between 2001 and 2003 during autumn, winter, and spring. Multivariate analyses (Cluster and MDS) were used to define sampling station groups, and a BIO-ENV procedure used to estimate the association of stations with environmental factors (depth, stratification, temperature and salinity of surface and bottom waters). The BIO-ENV procedure indicated that the salinity during autumn-winter and the temperature in spring had a significant influence on the spatial age-class pattern. The proportion of the youngest age-classes decreased from the estuarine area to the marine coastal area, except during spring where it showed the reverse pattern. The older age-classes inhabited the marine coastal area (more saline) toward the deepest zone, while the youngest individuals inhabited the outer estuarine area. Examination of the coastal circulation associated with the spatial distribution, and of the age-class frequency in the estuarine and marine coastal area, suggested that spawning took place in inshore coastal waters at very shallow depths.
Age distribution of anginose mononucleosis.
Spirer, Z; Holtzman, M; Melamed, I; Shalit, I
1987-01-01
The age distribution of anginose infectious mononucleosis in children was analysed retrospectively for the years 1966-85. During that period the disease became significantly more common in children of a young age and less common in older children. This shift could not be attributed either to socioeconomic conditions or to the diagnostic methods used. PMID:3619480
Multivariate distributions of soil hydraulic parameters
NASA Astrophysics Data System (ADS)
Qu, Wei; Pachepsky, Yakov; Huisman, Johan Alexander; Martinez, Gonzalo; Bogena, Heye; Vereecken, Harry
2014-05-01
Statistical distributions of soil hydraulic parameters have to be known when synthetic fields of soil hydraulic properties need to be generated in ensemble modeling of soil water dynamics and soil water content data assimilation. Pedotransfer functions that provide statistical distributions of water retention and hydraulic conductivity parameters for textural classes are most often used in the parameter field generation. Presence of strong correlations can substantially influence the parameter generation results. The objective of this work was to review and evaluate available data on correlations between van Genuchten-Mualem (VGM) model parameters. So far, two different approaches were developed to estimate these correlations. The first approach uses pedotransfer functions to generate VGM parameters for a large number of soil compositions within a textural class, and then computes parameter correlations for each of the textural classes. The second approach computes the VGM parameter correlations directly from parameter values obtained by fitting VGM model to measured water retention and hydraulic conductivity data for soil samples belonging to a textural class. Carsel and Parish (1988) used the Rawls et al. (1982) pedotransfer functions, and Meyer et al. (1997) used the Rosetta pedotransfer algorithms (Schaap, 2002) to develop correlations according to the first approach. We used the UNSODA database (Nemes et al. 2001), the US Southern Plains database (Timlin et al., 1999), and the Belgian database (Vereecken et al., 1989, 1990) to apply the second approach. A substantial number of considerable (>0.7) correlation coefficients were found. Large differences were encountered between parameter correlations obtained with different approaches and different databases for the same textural classes. The first of the two approaches resulted in generally higher values of correlation coefficients between VGM parameters. However, results of the first approach application depend
Parton Distributions in the Impact Parameter Space
Matthias Burkardt
2009-08-01
Parton distributions in impact parameter space, which are obtained by Fourier transforming GPDs, exhibit a significant deviation from axial symmetry when the target and/or quark is transversely polarized. In combination with the final state interactions, this transverse deformation provides a natural mechanism for naive-T odd transverse single-spin asymmetries in semi-inclusive DIS. The deformation can also be related to the transverse force acting on the active quark in polarized DIS at higher twist.
Distributed parameter statics of magnetic catheters.
Tunay, Ilker
2011-01-01
We discuss how to use special Cosserat rod theory for deriving distributed-parameter static equilibrium equations of magnetic catheters. These medical devices are used for minimally-invasive diagnostic and therapeutic procedures and can be operated remotely or controlled by automated algorithms. The magnetic material can be lumped in rigid segments or distributed in flexible segments. The position vector of the cross-section centroid and quaternion representation of an orthonormal triad are selected as DOF. The strain energy for transversely isotropic, hyperelastic rods is augmented with the mechanical potential energy of the magnetic field and a penalty term to enforce the quaternion unity constraint. Numerical solution is found by 1D finite elements. Material properties of polymer tubes in extension, bending and twist are determined by mechanical and magnetic experiments. Software experiments with commercial FEM software indicate that the computational effort with the proposed method is at least one order of magnitude less than standard 3D FEM.
Determination of dose distributions and parameter sensitivity
Napier, B.A.; Farris, W.T.; Simpson, J.C.
1992-12-01
A series of scoping calculations has been undertaken to evaluate the absolute and relative contribution of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 005) examined the contributions of numerous parameters to the uncertainty distribution of doses calculated for environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow's milk and the third scoping study, which added additional pathways. Addressed in this calculation were the contributions to thyroid dose of infants from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows' milk from Feeding Regime 1 as described in Calculation 001.
The global age distribution of granitic pegmatites
McCauley, Andrew; Bradley, Dwight C.
2014-01-01
An updated global compilation of 377 new and previously published ages indicates that granitic pegmatites range in age from Mesoarchean to Neogene and have a semi-periodic age distribution. Undivided granitic pegmatites show twelve age maxima: 2913, 2687, 2501, 1853, 1379, 1174, 988, 525, 483, 391, 319, and 72 Ma. These peaks correspond broadly with various proxy records of supercontinent assembly, including the age distributions of granites, detrital zircon grains, and passive margins. Lithium-cesium-tantalum (LCT) pegmatites have a similar age distribution to the undivided granitic pegmatites, with maxima at 2638, 1800, 962, 529, 485, 371, 309, and 274 Ma. Lithium and Ta resources in LCT pegmatites are concentrated in the Archean and Phanerozoic. While there are some Li resources from the Proterozoic, the dominantly bimodal distribution of resources is particularly evident for Ta. This distribution is similar to that of orogenic gold deposits, and has been interpreted to reflect the preservation potential of the orogenic belts where these deposits are formed. Niobium-yttrium-fluorine (NYF) pegmatites show similar age distributions to LCT pegmatites, but with a strong maximum at ca. 1000 Ma.
Linking age, survival, and transit time distributions
NASA Astrophysics Data System (ADS)
Calabrese, Salvatore; Porporato, Amilcare
2015-10-01
Although the concepts of age, survival, and transit time have been widely used in many fields, including population dynamics, chemical engineering, and hydrology, a comprehensive mathematical framework is still missing. Here we discuss several relationships among these quantities by starting from the evolution equation for the joint distribution of age and survival, from which the equations for age and survival time readily follow. It also becomes apparent how the statistical dependence between age and survival is directly related to either the age dependence of the loss function or the survival-time dependence of the input function. The solution of the joint distribution equation also allows us to obtain the relationships between the age at exit (or death) and the survival time at input (or birth), as well as to stress the symmetries of the various distributions under time reversal. The transit time is then obtained as a sum of the age and survival time, and its properties are discussed along with the general relationships between their mean values. The special case of steady state case is analyzed in detail. Some examples, inspired by hydrologic applications, are presented to illustrate the theory with the specific results. This article was corrected on 11 Nov 2015. See the end of the full text for details.
Age structure and income distribution policy.
Von Weizsacker, R K
1988-01-01
The dependence of earnings on age is a firmly established empirical fact. A simple microeconomic model of educational choice, being consistent with this observation, is designed. The model lends itself readily to aggregation over individuals and age groups. Thus, relations can be set up between economic variables influencing the aggregate distribution of labor incomes and demographic variables determining the age structure of the population. The main results of the present study are: 1) overall earnings inequality is shown to be an increasing function of life expectancy and a decreasing function of fertility. 2) The effectiveness of redistributive policies is sensitive to the age composition. In particular, the inequality-reducing effect of a 1% income tax rise is shown to be smaller the older the population.
Novel regression equations predicting lung age from varied spirometric parameters.
Yamaguchi, Kazuhiro; Omori, Hisamitsu; Onoue, Ayumi; Katoh, Takahiko; Ogata, Yasuhiro; Kawashima, Hidetoshi; Onizawa, Shigemitsu; Tsuji, Takao; Aoshiba, Kazutetsu; Nagai, Atsushi
2012-08-15
Although lung age calculated backward from regression formulas constructed for FEV(1) estimation is widely used, it possesses a couple of faults. We developed novel equations predicting lung age from varied spirometric parameters (spirometry-derived lung age (SDL-age)). Applying multiple regression analysis, equations predicting SDL-age were invented using data from 8015 never-smokers with normal spirometry (group I). Validation was made based on data from 6398 never-smokers with normal spirometry (group II). Equations were further applied for 446 subjects with airflow limitation. FEV(1), FEV(1)/FVC, FEF(50), and PEF were selected as explanatory variables for reference value of SDL-age. Normal limits of difference between SDL-age and chronological-age were ± 13.4 years in the male and ± 15.0 years in the female. Established equations predicted SDL-age of group II. SDL-age was older than chronological-age only in subjects with severe airflow limitation. Novel regression equations allowing prediction of reference value of SDL-age and normal limits of difference between SDL-age and chronological-age were elaborated in both genders.
Theoretical foundation for measuring the groundwater age distribution.
Gardner, William Payton; Arnold, Bill Walter
2014-01-01
In this study, we use PFLOTRAN, a highly scalable, parallel, flow and reactive transport code to simulate the concentrations of 3H, 3He, CFC-11, CFC-12, CFC-113, SF6, 39Ar, 81Kr, 4He and themean groundwater age in heterogeneous fields on grids with an excess of 10 million nodes. We utilize this computational platform to simulate the concentration of multiple tracers in high-resolution, heterogeneous 2-D and 3-D domains, and calculate tracer-derived ages. Tracer-derived ages show systematic biases toward younger ages when the groundwater age distribution contains water older than the maximum tracer age. The deviation of the tracer-derived age distribution from the true groundwater age distribution increases with increasing heterogeneity of the system. However, the effect of heterogeneity is diminished as the mean travel time gets closer the tracer age limit. Age distributions in 3-D domains differ significantly from 2-D domains. 3D simulations show decreased mean age, and less variance in age distribution for identical heterogeneity statistics. High-performance computing allows for investigation of tracer and groundwater age systematics in high-resolution domains, providing a platform for understanding and utilizing environmental tracer and groundwater age information in heterogeneous 3-D systems. Groundwater environmental tracers can provide important constraints for the calibration of groundwater flow models. Direct simulation of environmental tracer concentrations in models has the additional advantage of avoiding assumptions associated with using calculated groundwater age values. This study quantifies model uncertainty reduction resulting from the addition of environmental tracer concentration data. The analysis uses a synthetic heterogeneous aquifer and the calibration of a flow and transport model using the pilot point method. Results indicate a significant reduction in the uncertainty in permeability with the addition of environmental tracer data, relative
Lattice parameter variations during aging in nickel-base superalloys
NASA Technical Reports Server (NTRS)
Nathal, M. V.; Mackay, R. A.; Garlick, R. G.
1988-01-01
The importance of the state of coherency on measurements of gamma/gamma-prime lattice mismatch has been experimentally demonstrated during aging at 1000 C of specimens of an alloy with composition Ni-(8.6)Cr-(5.3)Al-(10.1)Co-(11.7)W-(1.2)Ti-(0.7)Mo (wt pct). Lattice parameter measurements are given as a function of aging time, and the corresponding sample microstructures are presented. The results show that changes of the two phases during aging did not influence the lattice parameter measurements, indicating that aging specimens to produce a semicoherent gamma/gamma-prime structure provides a good approximation of the true, unconstrained lattice mismatch.
Parameter identification in periodic delay differential equations with distributed delay
NASA Astrophysics Data System (ADS)
Torkamani, Shahab; Butcher, Eric A.; Khasawneh, Firas A.
2013-04-01
In this study, a parameter identification approach for identifying the parameters of a periodic delayed system with distributed delay is introduced based on time series analysis and spectral element analysis. Using this approach the parameters of the distributed delayed system can be identified from the time series of the response of the system. The experimental or numerical data of the response is examined with Floquet theory and time series analysis techniques to estimate a reduced order dynamics, or truncated state space to identify the Floquet multipliers. Parameter identification is then completed using a dynamic map developed for the assumed model of the system which can relate the Floquet multipliers to the unknown parameters in the model. The parameter identification technique is validated numerically for first and second order delay differential equations with distributed delay.
Large capacitor performs as a distributed parameter pulse line
NASA Technical Reports Server (NTRS)
Gooding, T. J.
1966-01-01
Capacitor of extended foil construction performs as a distributed parameter pulse line in which current, amplitude, and period are readily controlled. The capacitor is used as the energy storage element in a pulsed plasma accelerator.
Kalman filter application for distributed parameter estimation in reactor systems
Martin, R.P.; Edwards, R.M.
1996-07-01
An application of the Kalman filter has been developed for the real-time identification of a distributed parameter in a nuclear power plant. This technique can be used to improve numerical method-based best-estimate simulation of complex systems such as nuclear power plants. The application to a reactor system involves a unique modal model that approximates physical components, such as the reactor, as a coupled oscillator, i.e., a modal model with coupled modes. In this model both states and parameters are described by an orthogonal expansion. The Kalman filter with the sequential least-squares parameter estimation algorithm was used to estimate the modal coefficients of all states and one parameter. Results show that this state feedback algorithm is an effective way to parametrically identify a distributed parameter system in the presence of uncertainties.
Rebec, Katja Malovrh; Klanjšek-Gunde, Marta; Bizjak, Grega; Kobav, Matej B
2015-01-01
Ergonomic science at work and living places should appraise human factors concerning the photobiological effects of lighting. Thorough knowledge on this subject has been gained in the past; however, few attempts have been made to propose suitable evaluation parameters. The blue light hazard and its influence on melatonin secretion in age-dependent observers is considered in this paper and parameters for its evaluation are proposed. New parameters were applied to analyse the effects of white light-emitting diode (LED) light sources and to compare them with the currently applied light sources. The photobiological effects of light sources with the same illuminance but different spectral power distribution were determined for healthy 4-76-year-old observers. The suitability of new parameters is discussed. Correlated colour temperature, the only parameter currently used to assess photobiological effects, is evaluated and compared to new parameters. PMID:26647954
Distribution of water quality parameters in Dhemaji district, Assam (India).
Buragohain, Mridul; Bhuyan, Bhabajit; Sarma, H P
2010-07-01
The primary objective of this study is to present a statistically significant water quality database of Dhemaji district, Assam (India) with special reference to pH, fluoride, nitrate, arsenic, iron, sodium and potassium. 25 water samples collected from different locations of five development blocks in Dhemaji district have been studied separately. The implications presented are based on statistical analyses of the raw data. Normal distribution statistics and reliability analysis (correlation and covariance matrix) have been employed to find out the distribution pattern, localisation of data, and other related information. Statistical observations show that all the parameters under investigation exhibit non uniform distribution with a long asymmetric tail either on the right or left side of the median. The width of the third quartile was consistently found to be more than the second quartile for each parameter. Differences among mean, mode and median, significant skewness and kurtosis value indicate that the distribution of various water quality parameters in the study area is widely off normal. Thus, the intrinsic water quality is not encouraging due to unsymmetrical distribution of various water quality parameters in the study area.
The Power of Heterogeneity: Parameter Relationships from Distributions.
Röding, Magnus; Bradley, Siobhan J; Williamson, Nathan H; Dewi, Melissa R; Nann, Thomas; Nydén, Magnus
2016-01-01
Complex scientific data is becoming the norm, many disciplines are growing immensely data-rich, and higher-dimensional measurements are performed to resolve complex relationships between parameters. Inherently multi-dimensional measurements can directly provide information on both the distributions of individual parameters and the relationships between them, such as in nuclear magnetic resonance and optical spectroscopy. However, when data originates from different measurements and comes in different forms, resolving parameter relationships is a matter of data analysis rather than experiment. We present a method for resolving relationships between parameters that are distributed individually and also correlated. In two case studies, we model the relationships between diameter and luminescence properties of quantum dots and the relationship between molecular weight and diffusion coefficient for polymers. Although it is expected that resolving complicated correlated relationships require inherently multi-dimensional measurements, our method constitutes a useful contribution to the modelling of quantitative relationships between correlated parameters and measurements. We emphasise the general applicability of the method in fields where heterogeneity and complex distributions of parameters are obstacles to scientific insight. PMID:27182701
The Power of Heterogeneity: Parameter Relationships from Distributions
Röding, Magnus; Bradley, Siobhan J.; Williamson, Nathan H.; Dewi, Melissa R.; Nann, Thomas; Nydén, Magnus
2016-01-01
Complex scientific data is becoming the norm, many disciplines are growing immensely data-rich, and higher-dimensional measurements are performed to resolve complex relationships between parameters. Inherently multi-dimensional measurements can directly provide information on both the distributions of individual parameters and the relationships between them, such as in nuclear magnetic resonance and optical spectroscopy. However, when data originates from different measurements and comes in different forms, resolving parameter relationships is a matter of data analysis rather than experiment. We present a method for resolving relationships between parameters that are distributed individually and also correlated. In two case studies, we model the relationships between diameter and luminescence properties of quantum dots and the relationship between molecular weight and diffusion coefficient for polymers. Although it is expected that resolving complicated correlated relationships require inherently multi-dimensional measurements, our method constitutes a useful contribution to the modelling of quantitative relationships between correlated parameters and measurements. We emphasise the general applicability of the method in fields where heterogeneity and complex distributions of parameters are obstacles to scientific insight. PMID:27182701
Distribution of coal quality parameters in lignites of northeast Texas
Crowley, S.S.; Warwick, P.D.; Thomas, R.E.; Mason, W.H.
1996-12-31
The distribution of coal quality characteristics was examined in lignites (Wilcox Group, Paleocene-Eocene) near Mt. Pleasant, Texas. Coal quality parameters including ash yield, sulfur forms, moisture, calorific value, and selected potentially hazardous trace elements were plotted on cross sections of lignite beds to determine their stratigraphic distribution. This study has been undertaken as a part of the US Geological Survey`s National Coal Resource Assessment (NCRA) program in the Gulf Coast Lignite Region. The distribution in coal of Hazardous Air Pollutant elements (HAPs), as defined in the Clean Air Act Amendments of 1990, are an important focus of the NCRA program.
Distributional Phonetic Learning at 10 Months of Age
ERIC Educational Resources Information Center
Yoshida, Katherine A.; Pons, Ferran; Maye, Jessica; Werker, Janet F.
2010-01-01
Infant phonetic perception reorganizes in accordance with the native language by 10 months of age. One mechanism that may underlie this perceptual change is distributional learning, a statistical analysis of the distributional frequency of speech sounds. Previous distributional learning studies have tested infants of 6-8 months, an age at which…
Chandrasekhar equations and computational algorithms for distributed parameter systems
NASA Technical Reports Server (NTRS)
Burns, J. A.; Ito, K.; Powers, R. K.
1984-01-01
The Chandrasekhar equations arising in optimal control problems for linear distributed parameter systems are considered. The equations are derived via approximation theory. This approach is used to obtain existence, uniqueness, and strong differentiability of the solutions and provides the basis for a convergent computation scheme for approximating feedback gain operators. A numerical example is presented to illustrate these ideas.
Distributed parameter modelling of flexible spacecraft: Where's the beef?
NASA Technical Reports Server (NTRS)
Hyland, D. C.
1994-01-01
This presentation discusses various misgivings concerning the directions and productivity of Distributed Parameter System (DPS) theory as applied to spacecraft vibration control. We try to show the need for greater cross-fertilization between DPS theorists and spacecraft control designers. We recommend a shift in research directions toward exploration of asymptotic frequency response characteristics of critical importance to control designers.
Iterative methods for distributed parameter estimation in parabolic PDE
Vogel, C.R.; Wade, J.G.
1994-12-31
The goal of the work presented is the development of effective iterative techniques for large-scale inverse or parameter estimation problems. In this extended abstract, a detailed description of the mathematical framework in which the authors view these problem is presented, followed by an outline of the ideas and algorithms developed. Distributed parameter estimation problems often arise in mathematical modeling with partial differential equations. They can be viewed as inverse problems; the `forward problem` is that of using the fully specified model to predict the behavior of the system. The inverse or parameter estimation problem is: given the form of the model and some observed data from the system being modeled, determine the unknown parameters of the model. These problems are of great practical and mathematical interest, and the development of efficient computational algorithms is an active area of study.
NASA Technical Reports Server (NTRS)
Kozu, Toshiaki; Nakamura, Kenji; Meneghini, Robert
1991-01-01
A method to estimate raindrop size distribution (DSD) parameters from a combined Zm profile and path-integrated attenuation is shown, and a test result of the method using the data from an aircraft experiment is presented. The 'semi' dual-parameter (SDP) measurement is employed to estimate DSD parameters using the data obtained from an aircraft experiment conducted by Communications Research Laboratory, Tokyo, in conjunction with NASA. The validity of estimated DSD parameters is examined using measured Ka-band radar reflectivities. The estimated path-averaged N(0) is consistent with the Ka/X Ze ratio, and the use of estimated DSD shows excellent agreement between the rain rates estimated from the X-band and K-band Zes. The feasibility of estimating DSD parameters from space is confirmed.
Huang, Dan; Chen, Xuejuan; Gong, Qi; Yuan, Chaoqun; Ding, Hui; Bai, Jing; Zhu, Hui; Fu, Zhujun; Yu, Rongbin; Liu, Hu
2016-01-01
This survey was conducted to determine the testability, distribution and associations of ocular biometric parameters in Chinese preschool children. Ocular biometric examinations, including the axial length (AL) and corneal radius of curvature (CR), were conducted on 1,688 3-year-old subjects by using an IOLMaster in August 2015. Anthropometric parameters, including height and weight, were measured according to a standardized protocol, and body mass index (BMI) was calculated. The testability was 93.7% for the AL and 78.6% for the CR overall, and both measures improved with age. Girls performed slightly better in AL measurements (P = 0.08), and the difference in CR was statistically significant (P < 0.05). The AL distribution was normal in girls (P = 0.12), whereas it was not in boys (P < 0.05). For CR1, all subgroups presented normal distributions (P = 0.16 for boys; P = 0.20 for girls), but the distribution varied when the subgroups were combined (P < 0.05). CR2 presented a normal distribution (P = 0.11), whereas the AL/CR ratio was abnormal (P < 0.001). Boys exhibited a significantly longer AL, a greater CR and a greater AL/CR ratio than girls (all P < 0.001).
Huang, Dan; Chen, Xuejuan; Gong, Qi; Yuan, Chaoqun; Ding, Hui; Bai, Jing; Zhu, Hui; Fu, Zhujun; Yu, Rongbin; Liu, Hu
2016-01-01
This survey was conducted to determine the testability, distribution and associations of ocular biometric parameters in Chinese preschool children. Ocular biometric examinations, including the axial length (AL) and corneal radius of curvature (CR), were conducted on 1,688 3-year-old subjects by using an IOLMaster in August 2015. Anthropometric parameters, including height and weight, were measured according to a standardized protocol, and body mass index (BMI) was calculated. The testability was 93.7% for the AL and 78.6% for the CR overall, and both measures improved with age. Girls performed slightly better in AL measurements (P = 0.08), and the difference in CR was statistically significant (P < 0.05). The AL distribution was normal in girls (P = 0.12), whereas it was not in boys (P < 0.05). For CR1, all subgroups presented normal distributions (P = 0.16 for boys; P = 0.20 for girls), but the distribution varied when the subgroups were combined (P < 0.05). CR2 presented a normal distribution (P = 0.11), whereas the AL/CR ratio was abnormal (P < 0.001). Boys exhibited a significantly longer AL, a greater CR and a greater AL/CR ratio than girls (all P < 0.001). PMID:27384307
Huang, Dan; Chen, Xuejuan; Gong, Qi; Yuan, Chaoqun; Ding, Hui; Bai, Jing; Zhu, Hui; Fu, Zhujun; Yu, Rongbin; Liu, Hu
2016-01-01
This survey was conducted to determine the testability, distribution and associations of ocular biometric parameters in Chinese preschool children. Ocular biometric examinations, including the axial length (AL) and corneal radius of curvature (CR), were conducted on 1,688 3-year-old subjects by using an IOLMaster in August 2015. Anthropometric parameters, including height and weight, were measured according to a standardized protocol, and body mass index (BMI) was calculated. The testability was 93.7% for the AL and 78.6% for the CR overall, and both measures improved with age. Girls performed slightly better in AL measurements (P = 0.08), and the difference in CR was statistically significant (P < 0.05). The AL distribution was normal in girls (P = 0.12), whereas it was not in boys (P < 0.05). For CR1, all subgroups presented normal distributions (P = 0.16 for boys; P = 0.20 for girls), but the distribution varied when the subgroups were combined (P < 0.05). CR2 presented a normal distribution (P = 0.11), whereas the AL/CR ratio was abnormal (P < 0.001). Boys exhibited a significantly longer AL, a greater CR and a greater AL/CR ratio than girls (all P < 0.001). PMID:27384307
Control of the SCOLE configuration using distributed parameter models
NASA Technical Reports Server (NTRS)
Hsiao, Min-Hung; Huang, Jen-Kuang
1994-01-01
A continuum model for the SCOLE configuration has been derived using transfer matrices. Controller designs for distributed parameter systems have been analyzed. Pole-assignment controller design is considered easy to implement but stability is not guaranteed. An explicit transfer function of dynamic controllers has been obtained and no model reduction is required before the controller is realized. One specific LQG controller for continuum models had been derived, but other optimal controllers for more general performances need to be studied.
Testing Distributed Parameter Hypotheses for the Detection of Climate Change.
NASA Astrophysics Data System (ADS)
Kheshgi, Haroon S.; White, Benjamin S.
2001-08-01
A general statistical methodology, based on testing alternative distributed parameter hypotheses, is proposed as a method for deciding whether or not anthropogenic influences are causing climate change. This methodology provides a framework for including known uncertainties in the definition of the hypotheses by allowing model parameters to be specified by probability distributions and thereby allowing the definition of more realistic hypotheses. The method can be used to derive the unique statistical test that minimizes errors in test conclusions. The method is applied to illustrative detection problems by first defining alternative hypotheses for global mean temperature; second, deriving the most powerful test and calculating its statistics; third, applying the test to observed temperature records; and finally, illustrating the test statistics and results on a receiver or relative operating characteristic curve showing the relation between false positive and false negative test errors. It is demonstrated, with an illustrative example, that proper accounting for the uncertainty in all the parameters can produce very different statistical conclusions than the conclusions that would be obtained by simply fixing some parameters at nominal values.
Parameter estimation for the distribution of single cell lag times.
Baranyi, József; George, Susan M; Kutalik, Zoltán
2009-07-01
In Quantitative Microbial Risk Assessment, it is vital to understand how lag times of individual cells are distributed over a bacterial population. Such identified distributions can be used to predict the time by which, in a growth-supporting environment, a few pathogenic cells can multiply to a poisoning concentration level. We model the lag time of a single cell, inoculated into a new environment, by the delay of the growth function characterizing the generated subpopulation. We introduce an easy-to-implement procedure, based on the method of moments, to estimate the parameters of the distribution of single cell lag times. The advantage of the method is especially apparent for cases where the initial number of cells is small and random, and the culture is detectable only in the exponential growth phase.
Age distribution among NASA scientists and engineers
NASA Technical Reports Server (NTRS)
Ciancone, Michael L.
1989-01-01
The loss of technical expertise through attrition in NASA and the aerospace industry is discussed. This report documents historical age-related information for scientific and engineering personnel in general and the NASA Lewis Research Center in particular, for 1968 through 1987. Recommendations are made to promote discussion and to establish the groundwork for action.
Skeletal distribution and biochemical parameters of Paget's disease
Meunier, P.J.; Salson, C.; Mathieu, L.; Chapuy, M.C.; Delmas, P.; Alexandre, C.; Charhon, S.
1987-04-01
Quantitative bone scans were performed with /sup 99m/Tc-EHDP in 170 untreated pagetic patients (93 men, 77 women; mean age, 65.4 years). The distribution of 863 pagetic skeletal locations was analyzed. Bone scans demonstrated 8.3% more pagetic sites than roentgenograms. The extent of Paget's disease was evaluated in each patient by a scintigraphic skeletal index. This index correlated with serum alkaline phosphatase (SAP) and urinary hydroxyproline (HyPro) levels, and also with hypocalcemic acute response to calcitonin. The correlation of SAP with an index of activity (extent index adjusted by uptake ratios) was better than with the nonadjusted index. Only 30.6% of pagetic sites were responsible for clinical symptoms. No correlation was found between age and skeletal index of the disease.
Control of complex dynamics and chaos in distributed parameter systems
Chakravarti, S.; Marek, M.; Ray, W.H.
1995-12-31
This paper discusses a methodology for controlling complex dynamics and chaos in distributed parameter systems. The reaction-diffusion system with Brusselator kinetics, where the torus-doubling or quasi-periodic (two characteristic incommensurate frequencies) route to chaos exists in a defined range of parameter values, is used as an example. Poincare maps are used for characterization of quasi-periodic and chaotic attractors. The dominant modes or topos, which are inherent properties of the system, are identified by means of the Singular Value Decomposition. Tested modal feedback control schemas based on identified dominant spatial modes confirm the possibility of stabilization of simple quasi-periodic trajectories in the complex quasi-periodic or chaotic spatiotemporal patterns.
Transfer function modeling of damping mechanisms in distributed parameter models
NASA Technical Reports Server (NTRS)
Slater, J. C.; Inman, D. J.
1994-01-01
This work formulates a method for the modeling of material damping characteristics in distributed parameter models which may be easily applied to models such as rod, plate, and beam equations. The general linear boundary value vibration equation is modified to incorporate hysteresis effects represented by complex stiffness using the transfer function approach proposed by Golla and Hughes. The governing characteristic equations are decoupled through separation of variables yielding solutions similar to those of undamped classical theory, allowing solution of the steady state as well as transient response. Example problems and solutions are provided demonstrating the similarity of the solutions to those of the classical theories and transient responses of nonviscous systems.
Radial Distributions of Dusty Plasma Parameters in a Glow Discharge
Fedoseev, A. V.; Sukhinin, G. I.
2011-11-29
A self-consistent model for radial distributions of dusty plasma parameters in a DC glow discharge based on the non-local Boltzmann equation for EEDF, the drift-diffusion equation for ions, and the Poisson equation for self-consistent electric field is presented. The results show that for the case of high dust particles density when the recombination of electrons and ions exceeds the ionization near the tube axis, radial electron and ion fluxes change their direction toward the center of the tube, and the radial electric field is reversed.
Optimal vibration control of curved beams using distributed parameter models
NASA Astrophysics Data System (ADS)
Liu, Fushou; Jin, Dongping; Wen, Hao
2016-12-01
The design of linear quadratic optimal controller using spectral factorization method is studied for vibration suppression of curved beam structures modeled as distributed parameter models. The equations of motion for active control of the in-plane vibration of a curved beam are developed firstly considering its shear deformation and rotary inertia, and then the state space model of the curved beam is established directly using the partial differential equations of motion. The functional gains for the distributed parameter model of curved beam are calculated by extending the spectral factorization method. Moreover, the response of the closed-loop control system is derived explicitly in frequency domain. Finally, the suppression of the vibration at the free end of a cantilevered curved beam by point control moment is studied through numerical case studies, in which the benefit of the presented method is shown by comparison with a constant gain velocity feedback control law, and the performance of the presented method on avoidance of control spillover is demonstrated.
C -parameter distribution at N3LL' including power corrections
NASA Astrophysics Data System (ADS)
Hoang, André H.; Kolodrubetz, Daniel W.; Mateu, Vicent; Stewart, Iain W.
2015-05-01
We compute the e+e- C -parameter distribution using the soft-collinear effective theory with a resummation to next-to-next-to-next-to-leading-log prime accuracy of the most singular partonic terms. This includes the known fixed-order QCD results up to O (αs3), a numerical determination of the two-loop nonlogarithmic term of the soft function, and all logarithmic terms in the jet and soft functions up to three loops. Our result holds for C in the peak, tail, and far tail regions. Additionally, we treat hadronization effects using a field theoretic nonperturbative soft function, with moments Ωn. To eliminate an O (ΛQCD) renormalon ambiguity in the soft function, we switch from the MS ¯ to a short distance "Rgap" scheme to define the leading power correction parameter Ω1. We show how to simultaneously account for running effects in Ω1 due to renormalon subtractions and hadron-mass effects, enabling power correction universality between C -parameter and thrust to be tested in our setup. We discuss in detail the impact of resummation and renormalon subtractions on the convergence. In the relevant fit region for αs(mZ) and Ω1, the perturbative uncertainty in our cross section is ≃ 2.5 % at Q =mZ.
C -parameter distribution at N 3 LL ' including power corrections
Hoang, André H.; Kolodrubetz, Daniel W.; Mateu, Vicent; Stewart, Iain W.
2015-05-15
We compute the e⁺e⁻ C-parameter distribution using the soft-collinear effective theory with a resummation to next-to-next-to-next-to-leading-log prime accuracy of the most singular partonic terms. This includes the known fixed-order QCD results up to O(α3s), a numerical determination of the two-loop nonlogarithmic term of the soft function, and all logarithmic terms in the jet and soft functions up to three loops. Our result holds for C in the peak, tail, and far tail regions. Additionally, we treat hadronization effects using a field theoretic nonperturbative soft function, with moments Ωn. To eliminate an O(ΛQCD) renormalon ambiguity in the soft function, we switchmore » from the MS¯ to a short distance “Rgap” scheme to define the leading power correction parameter Ω1. We show how to simultaneously account for running effects in Ω1 due to renormalon subtractions and hadron-mass effects, enabling power correction universality between C-parameter and thrust to be tested in our setup. We discuss in detail the impact of resummation and renormalon subtractions on the convergence. In the relevant fit region for αs(mZ) and Ω1, the perturbative uncertainty in our cross section is ≅ 2.5% at Q=mZ.« less
Inversion of generalized relaxation time distributions with optimized damping parameter
NASA Astrophysics Data System (ADS)
Florsch, Nicolas; Revil, André; Camerlynck, Christian
2014-10-01
Retrieving the Relaxation Time Distribution (RDT), the Grains Size Distribution (GSD) or the Pore Size Distribution (PSD) from low-frequency impedance spectra is a major goal in geophysics. The “Generalized RTD” generalizes parametric models like Cole-Cole and many others, but remains tricky to invert since this inverse problem is ill-posed. We propose to use generalized relaxation basis function (for instance by decomposing the spectra on basis of generalized Cole-Cole relaxation elements instead of the classical Debye basis) and to use the L-curve approach to optimize the damping parameter required to get smooth and realistic inverse solutions. We apply our algorithm to three examples, one synthetic and two real data sets, and the program includes the possibility of converting the RTD into GSD or PSD by choosing the value of the constant connecting the relaxation time to the characteristic polarization size of interest. A high frequencies (typically above 1 kHz), a dielectric term in taken into account in the model. The code is provided as an open Matlab source as a supplementary file associated with this paper.
Vayá, Amparo; Sarnago, Ana; Fuster, Oscar; Alis, Rafael; Romagnoli, Marco
2015-01-01
Red blood cell distribution width (RDW) is a routine red blood cell count parameter which has been shown to be associated with inflammatory parameters. Recently, some authors proposed that RDW seems to be a marker of an adverse lipidic profile. In order to clarify whether RDW is related to inflammation, plasma lipids, or both, we determined anthropometric, hematimetric, inflammatory and lipidic parameters in 1111 healthy subjects. RDW correlated directly with age, body mass index (BMI), inflammatory parameters (plasma viscosity, erythrocyte sedimentation rate (ESR), fibrinogen, leukocyte and neutrophil count), and inversely with iron and hematimetric parameters (P < 0.05). When subjects were divided according to gender, RDW correlated inversely with triglycerides only in women (P < 0.05). When subjects were classified into RDW-quartiles, increased RDW values were accompanied by decreased serum iron levels and hematimetric indices (P < 0.01), whereas age and inflammatory markers increased according to RDW-quartiles (P < 0.001 and P < 0.05, respectively). However, plasma lipids did not change with increasing RDW-quartiles (P > 0.05). In the linear regression analysis, age, hemoglobin, MCV (beta coefficient: 0.202, -0.234, -0.316, P < 0.001) and fibrinogen (beta coefficient: 0.059, P = 0.048) were the only independent predictors of RDW. The present study indicates that RDW is associated with inflammatory markers and hematimetric indices, but not with plasma lipid levels in a healthy population. PMID:25159489
Sound propagation and absorption in foam - A distributed parameter model.
NASA Technical Reports Server (NTRS)
Manson, L.; Lieberman, S.
1971-01-01
Liquid-base foams are highly effective sound absorbers. A better understanding of the mechanisms of sound absorption in foams was sought by exploration of a mathematical model of bubble pulsation and coupling and the development of a distributed-parameter mechanical analog. A solution by electric-circuit analogy was thus obtained and transmission-line theory was used to relate the physical properties of the foams to the characteristic impedance and propagation constants of the analog transmission line. Comparison of measured physical properties of the foam with values obtained from measured acoustic impedance and propagation constants and the transmission-line theory showed good agreement. We may therefore conclude that the sound propagation and absorption mechanisms in foam are accurately described by the resonant response of individual bubbles coupled to neighboring bubbles.
Numerical studies of identification in nonlinear distributed parameter systems
NASA Technical Reports Server (NTRS)
Banks, H. T.; Lo, C. K.; Reich, Simeon; Rosen, I. G.
1989-01-01
An abstract approximation framework and convergence theory for the identification of first and second order nonlinear distributed parameter systems developed previously by the authors and reported on in detail elsewhere are summarized and discussed. The theory is based upon results for systems whose dynamics can be described by monotone operators in Hilbert space and an abstract approximation theorem for the resulting nonlinear evolution system. The application of the theory together with numerical evidence demonstrating the feasibility of the general approach are discussed in the context of the identification of a first order quasi-linear parabolic model for one dimensional heat conduction/mass transport and the identification of a nonlinear dissipation mechanism (i.e., damping) in a second order one dimensional wave equation. Computational and implementational considerations, in particular, with regard to supercomputing, are addressed.
Distributed parameter approach to the dynamics of complex biological processes
Lee, T.T.; Wang, F.Y.; Newell, R.B.
1999-10-01
Modeling and simulation of a complex biological process for the removal of nutrients (nitrogen and phosphorus) from municipal wastewater are addressed. The model developed in this work employs a distributed-parameter approach to describe the behavior of components within three different bioreaction zones and the behavior of sludge in the anaerobic zone and soluble phosphate in the aerobic zone in two experiments. Good results are achieved despite the apparent plant-model mismatch, such as uncertainties with the behavior of phosphorus-accumulating organisms. Validation of the proposed secondary-settler model shows that it is superior to two state-of-the-art models in terms of the sum of the square relative errors.
Tropea, Peppino; Martelli, Dario; Aprigliano, Federica; Micera, Silvestro; Monaco, Vito
2015-01-01
The aim of this study was to analyze the modifications of temporal parameters during slipping-like perturbations associated both with aging and perturbation intensities. Twelve participants equally distributed from two age groups (elderly and young) were recorded while, during steady locomotion, managing unexpected slipping-like perturbations, in forward direction, at different intensity and amplitude of foot shift. Two metrics were extrapolated from the analysis of the ground reaction force supplied by ad hoc platform aimed at destabilizing the balance control. The results indicated that the analyzed timing variables, both for elderly and young, are strongly modified by intensity of the perturbation, but only slight altered by the amplitude. Concerning the comparison about the two groups, elderly people seem to have slower reactive response than young subjects. These findings support further investigations in order to gain a better understanding of fall dynamics in elderly people.
NASA Astrophysics Data System (ADS)
Zurfluh, Florian J.; Hofmann, Beda A.; Gnos, Edwin; Eggenberger, Urs; Jull, A. J. Timothy
2016-09-01
We have investigated 128 14C-dated ordinary chondrites from Oman for macroscopically visible weathering parameters, for thin section-based weathering degrees, and for chemical weathering parameters as analyzed with handheld X-ray fluorescence. These 128 14C-dated meteorites show an abundance maximum of terrestrial age at 19.9 ka, with a mean of 21.0 ka and a pronounced lack of samples between 0 and 10 ka. The weathering degree is evaluated in thin section using a refined weathering scale based on the current W0 to W6 classification of Wlotzka (1993), with five newly included intermediate steps resulting in a total of nine (formerly six) steps. We find significant correlations between terrestrial ages and several macroscopic weathering parameters. The correlation of various chemical parameters including Sr and Ba with terrestrial age is not very pronounced. The microscopic weathering degree of metal and sulfides with newly added intermediate steps shows the best correlation with 14C terrestrial ages, demonstrating the significance of the newly defined weathering steps. We demonstrate that the observed 14C terrestrial age distribution can be modeled from the abundance of meteorites with different weathering degrees, allowing the evaluation of an age-frequency distribution for the whole meteorite population.
NASA Astrophysics Data System (ADS)
Chen, Xu; Zhang, Ji-Hong; Liu, Wei; Liang, Yong-Sheng; Feng, Ji-Qiang
2013-12-01
In the situation of limited bandwidth, how to improve the performance of scalable video coding plays an important role in video coding. The previously proposed scalable video coding optimization schemes concentrate on reducing coding computation or trying to achieve consistent video quality; however, the connections between coding scheme, transmission environments, and users' accesses manner were not jointly considered. This article proposes a H.264/SVC (scalable video codec) parameter optimization scheme, which attempt to make full use of limited bandwidth, to achieve better peak signal-to-noise ratio, based on the joint measure of user bandwidth range and probability density distribution. This algorithm constructs a relationship map which consists of the bandwidth range of multiple users and the quantified quality increments measure, QP e , in order to make effective use of the video coding bit-stream. A medium grain scalability fragmentation optimization algorithm is also presented with respect to user bandwidth probability density distribution, encoding bit rate, and scalability. Experiments on a public dataset show that this method provides significant average quality improvement for streaming video applications.
[Transformations of parameters in the generalized Poisson distribution for test data analysis].
Ogasawara, H
1996-02-01
The generalized Poisson distribution is a distribution which approximates various forms of mixtures of Poisson distributions. The mean and variance of the generalized Poisson distribution, which are simple functions of the two parameters of the distribution, are more useful than the original parameters in test data analysis. Therefore, we adopted two types of transformations of parameters. The first model has new parameters of mean and standard deviation. The second model contains new parameters of mean and variance/mean. An example indicates that the transformed parameters are convenient to understand the properties of data. PMID:8935832
Data-Driven H∞ Control for Nonlinear Distributed Parameter Systems.
Luo, Biao; Huang, Tingwen; Wu, Huai-Ning; Yang, Xiong
2015-11-01
The data-driven H∞ control problem of nonlinear distributed parameter systems is considered in this paper. An off-policy learning method is developed to learn the H∞ control policy from real system data rather than the mathematical model. First, Karhunen-Loève decomposition is used to compute the empirical eigenfunctions, which are then employed to derive a reduced-order model (ROM) of slow subsystem based on the singular perturbation theory. The H∞ control problem is reformulated based on the ROM, which can be transformed to solve the Hamilton-Jacobi-Isaacs (HJI) equation, theoretically. To learn the solution of the HJI equation from real system data, a data-driven off-policy learning approach is proposed based on the simultaneous policy update algorithm and its convergence is proved. For implementation purpose, a neural network (NN)- based action-critic structure is developed, where a critic NN and two action NNs are employed to approximate the value function, control, and disturbance policies, respectively. Subsequently, a least-square NN weight-tuning rule is derived with the method of weighted residuals. Finally, the developed data-driven off-policy learning approach is applied to a nonlinear diffusion-reaction process, and the obtained results demonstrate its effectiveness. PMID:26277007
Is age really the second parameter in globular clusters
Vandenberg, D.A.; Durrell, P.R. )
1990-01-01
From the close similarity of the magnitude difference between the tip of the red giant branch and the turnoff in the Fe/H = about -1.3 globular cluster NGC 288, NGC 362, and M5, it is inferred that the ages of these three systems (and Palomar 5, whose horizonal branch is used to define its distance relative to the others) are not detectably different. An identical conclusion, by similar means, is reached for the Fe/H = about -2.1 globular clusters M15, M30, M68, and M92. Several recent claims that age is responsible for the wide variation in horizontal-branch morphology among clusters of the same metal abundance are not supported. 73 refs.
THE AGE AND STELLAR PARAMETERS OF THE PROCYON BINARY SYSTEM
Liebert, James; Arnett, David; Fontaine, Gilles; Young, Patrick A.; Williams, Kurtis A. E-mail: darnett@as.arizona.edu E-mail: pyoung.3@asu.edu
2013-05-20
The Procyon AB binary system (orbital period 40.838 yr, a newly refined determination) is near and bright enough that the component radii, effective temperatures, and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are available from Hubble Space Telescope imaging, supported by ground-based astrometry and an excellent Hipparcos parallax; we use these for our preferred solution for the binary system. Other values for the masses are also considered. We have employed the TYCHO stellar evolution code to match the radius and luminosity of the F5 IV-V primary star to determine the system's most likely age as 1.87 {+-} 0.13 Gyr. Since prior studies of Procyon A found its abundance indistinguishable from solar, the solar composition of Asplund, Grevesse, and Sauval (Z = 0.014) is assumed for the Hertzsprung-Russell diagram fitting. An unsuccessful attempt to fit using the older solar abundance scale of Grevesse and Sauval (Z = 0.019) is also reported. For Procyon B, 11 new sequences for the cooling of non-DA white dwarfs have been calculated to investigate the dependences of the cooling age on (1) the mass, (2) core composition, (3) helium layer mass, and (4) heavy-element opacities in the helium envelope. Our calculations indicate a cooling age of 1.19 {+-} 0.11 Gyr, which implies that the progenitor mass of Procyon B was 2.59{sub -0.26}{sup +0.44} M{sub Sun }. In a plot of initial versus final mass of white dwarfs in astrometric binaries or star clusters (all with age determinations), the Procyon B final mass lies several {sigma} below a straight line fit.
Estimating the Age Distribution of Oceanic Dissolved Organic Carbon
NASA Astrophysics Data System (ADS)
Follett, C. L.; Forney, D. C.; Repeta, D.; Rothman, D.
2010-12-01
Dissolved organic carbon (DOC) is a large, ubiquitous component of open ocean water at all depths and impacts atmospheric carbon dioxide levels at both short and long timescales. It is currently believed that oceanic DOC contains a multi-thousand-year-old refractory deep-water component which is mixed with a young labile component in surface waters. Unfortunately, the only evidence for this comes from a few isolated depth profiles of both DOC concentration and bulk radiocarbon. Although the profile data is consistent with a two-component mixing model, directly separating the two components has proven to be a challenge. We explore the validity of the two component mixing model by directly estimating the age distribution of oceanic DOC. The two-component model suggests that the age distribution is composed of two distinct peaks. In order to obtain an estimate of the age distribution we first record changes in both concentration and percent radiocarbon as a sample is oxidized under ultra-violet radiation [1]. We formulate a mathematical model relating the age distribution to these changes, assuming that they result from components of different radiocarbon age and UV-reactivity. This allows us to numerically invert the data and estimate the age distribution. We apply our procedure to DOC samples collected from three distinct depths (50, 500, and 2000 meters) in the north-central Pacific Ocean. [1] S.R. Beaupre, E.R.M. Druffel, and S. Griffin. A low-blank photochemical extraction system for concentration and isotopic analyses of marine dissolved organic carbon. Limnol. Oceanogr. Methods, 5:174-184, 2007.
Effects of intraborehole flow on groundwater age distribution
Zinn, B.A.; Konikow, L.F.
2007-01-01
Environmental tracers are used to estimate groundwater ages and travel times, but the strongly heterogeneous nature of many subsurface environments can cause mixing between waters of highly disparate ages, adding additional complexity to the age-estimation process. Mixing may be exacerbated by the presence of wells because long open intervals or long screens with openings at multiple depths can transport water and solutes rapidly over a large vertical distance. The effect of intraborehole flow on groundwater age was examined numerically using direct age transport simulation coupled with the Multi-Node Well Package of MODFLOW. Ages in a homogeneous, anisotropic aquifer reached a predevelopment steady state possessing strong depth dependence. A nonpumping multi-node well was then introduced in one of three locations within the system. In all three cases, vertical transport along the well resulted in substantial changes in age distributions within the system. After a pumping well was added near the nonpumping multi-node well, ages were further perturbed by a flow reversal in the nonpumping multi-node well. Results indicated that intraborehole flow can substantially alter groundwater ages, but the effects are highly dependent on local or regional flow conditions and may change with time. ?? Springer-Verlag 2007.
NASA Astrophysics Data System (ADS)
Massoudieh, Arash; Sharifi, Soroosh; Solomon, D. Kip
2012-09-01
The development of a Bayesian modeling approach for estimation of the age distribution of groundwater using radioactive isotopes and anthropogenic chemicals is described. The model considers the uncertainties associated with the measured tracer concentrations as well as the parameters affecting the concentration of tracers in the groundwater, and it provides the posterior probability densities of the parameters defining the groundwater age distribution using a Markov chain Monte Carlo method. The model also incorporates the effect of dissolution of aquifer minerals on diluting the 14C signature and the uncertainties associated with this process on the inferred age distribution parameters. Two demonstration modeling cases have been performed. First, the method was applied to simulated tracer concentrations at a discharge point of a hypothetical 2-D vertical aquifer with two recharge zones, leading to a mixed groundwater age distribution under different presumed uncertainties. When the error variance of the observed tracer concentrations is considered unknown, the method can estimate the parameters of the fitted exponential-lognormal distribution with a relatively narrow credible interval when five hypothetical samples are assumed to be collected at the discharge point. However, when a single sample is assumed, the credible intervals become wider, and credible estimations of the parameters are not obtained. Second, the method was applied to the data collected at La Selva Biological Station in Costa Rica. In this demonstration application, nine different forms of presumed groundwater age distributions have been considered, including four single forms and five mixed forms, assuming the groundwater consists of distinct young and old fractions. For the medium geometrical standard deviationδc,i = 1.41, the model estimates a young groundwater age of between 0 and 350 years, with the largest odds being given to a mean age of approximately 100 years, and a fraction of young
Pension benefits among the aged: conflicting measures, unequal distributions.
Woods, J R
1996-01-01
Estimates of total benefits paid by employer sponsored pension plans seem to vary widely between different data sources and measures. Such discrepancies have been used to support differing conclusions about the effectiveness of the pension system. This article examines several measures of aggregate pension benefits in 1990, a year particularly rich in available data. Exploratory analysis suggests that the greatest source of discrepancy lies in differing treatments of lump-sum distributions, although the study also identifies several other types of payments that are variously, and erroneously, counted as pension income. Age of recipients is an important factor in analyzing different measures of aggregate pension benefits; discrepancies are much smaller among the aged than in the population as a whole. The analysis also provides new evidence about the unequal distribution of pension benefits among the aged, confirming from two data sources that benefits are heavily concentrated among higher income groups.
[Change of clinical stomatological parameters in ageing (author's transl)].
Fassauer, H; Schottke, C
1978-01-01
Morphological-functional changes occur in the oral cavity also in depended from the age. The morphological changes of the enamel, dentin, dental pulp, periodont, oral mucosa, salivary glands, tongue, maxillary bone and temporo-mandibular-joint change not only the functional cooperation of all parts in the orofacial system. They show effects for the whole body also. A complete gerostomatological standard does not exist for the whole gnathological system. But single indices for some partial components are known. For the judgement of the caries involvement it is possible to use the DMF-index, for which a special gerostomatological type exist. The periodontal diseases are classified adequately to the ARPA-nomenclature. For the judgement of odontolithiasis and oral hygienic conditions you can use the so called odontolith-Index (CI), the OH (oral hygienic debris) and the so called calculus-index (OHI-S). It is refered to different possibilities for classification of dentition with gaps.
Modeling the brain morphology distribution in the general aging population
NASA Astrophysics Data System (ADS)
Huizinga, W.; Poot, D. H. J.; Roshchupkin, G.; Bron, E. E.; Ikram, M. A.; Vernooij, M. W.; Rueckert, D.; Niessen, W. J.; Klein, S.
2016-03-01
Both normal aging and neurodegenerative diseases such as Alzheimer's disease cause morphological changes of the brain. To better distinguish between normal and abnormal cases, it is necessary to model changes in brain morphology owing to normal aging. To this end, we developed a method for analyzing and visualizing these changes for the entire brain morphology distribution in the general aging population. The method is applied to 1000 subjects from a large population imaging study in the elderly, from which 900 were used to train the model and 100 were used for testing. The results of the 100 test subjects show that the model generalizes to subjects outside the model population. Smooth percentile curves showing the brain morphology changes as a function of age and spatiotemporal atlases derived from the model population are publicly available via an interactive web application at agingbrain.bigr.nl.
Aged Boreal Biomass Burning Size Distributions from Bortas 2011
NASA Astrophysics Data System (ADS)
Pierce, J. R.; Sakamoto, K.; Allan, J. D.; Coe, H.; Taylor, J.; Duck, T.
2014-12-01
Biomass-burning aerosols contribute to aerosol radiative forcing on the climate system. The magnitude of this effect is partially determined by aerosol size distributions, which are strong functions of source fire characteristics (e.g. fuel type, MCE) and in-plume microphysical processing. The uncertainties in biomass-burning emission number size-distributions in climate model inventories lead to uncertainties in the CCN concentrations and forcing estimates derived from these models. The BORTAS-B measurement campaign was designed to sample boreal biomass-burning outflow over Eastern Canada in the summer of 2011. Using these BORTAS-B data, we implement plume criteria to isolate the characteristic size-distribution of aged biomass-burning emissions (aged ~ 1.5 - 2 days) from boreal wildfires in Northwestern Ontario. The composite median size-distribution yields a single dominant accumulation mode with Dpm = 232 nm, σ = 1.7, which are comparable to literature values of other aged plumes of a similar type. The organic aerosol enhancement ratios (ΔOA/ΔCO) along the path of Flight b622 show values of 0.08-0.18 μg m-3 ppbv-1 with no significant trend with distance from the source. This lack of enhancement ratio increase/decrease with distance suggests no detectable net OA production/evaporation within the aged plume over the sampling period. A Lagrangian microphysical model was used to determine an estimate of the freshly emitted size distribution and flux corresponding to the BORTAS-B aged size-distributions. The model was restricted to coagulation and dilution processes only based on the insignificant net OA production/evaporation derived from the ΔOA/ΔCO enhancement ratios. Depending on the, we estimate that the fresh-plume median diameter was in the range of 59-94 nm with modal widths in the range of 1.7-2.8. Thus, the size of the freshly emitted particles is somewhat unconstrained due to the uncertainties in the plume dilution rates.
Aged boreal biomass burning aerosol size distributions from BORTAS 2011
NASA Astrophysics Data System (ADS)
Sakamoto, K. M.; Allan, J. D.; Coe, H.; Taylor, J. W.; Duck, T. J.; Pierce, J. R.
2014-09-01
Biomass-burning aerosols contribute to aerosol radiative forcing on the climate system. The magnitude of this effect is partially determined by aerosol size distributions, which are functions of source fire characteristics (e.g. fuel type, MCE) and in-plume microphysical processing. The uncertainties in biomass-burning emission number size-distributions in climate model inventories lead to uncertainties in the CCN concentrations and forcing estimates derived from these models. The BORTAS-B measurement campaign was designed to sample boreal biomass-burning outflow over Eastern Canada in the summer of 2011. Using these BORTAS-B data, we implement plume criteria to isolate the characteristic size-distribution of aged biomass-burning emissions (aged ∼1-2 days) from boreal wildfires in Northwestern Ontario. The composite median size-distribution yields a single dominant accumulation mode with Dpm = 230 nm (number-median diameter), σ = 1.7, which are comparable to literature values of other aged plumes of a similar type. The organic aerosol enhancement ratios (ΔOA / ΔCO) along the path of Flight b622 show values of 0.05-0.18 μg m-3 ppbv-1 with no significant trend with distance from the source. This lack of enhancement ratio increase/decrease with distance suggests no detectable net OA production/evaporation within the aged plume over the sampling period. A Lagrangian microphysical model was used to determine an estimate of the freshly emitted size distribution corresponding to the BORTAS-B aged size-distributions. The model was restricted to coagulation and dilution processes based on the insignificant net OA production/evaporation derived from the ΔOA / ΔCO enhancement ratios. We estimate that the fresh-plume median diameter was in the range of 59-94 nm with modal widths in the range of 1.7-2.8 (the ranges are due to uncertainty in the entrainment rate). Thus, the size of the freshly emitted particles is relatively unconstrained due to the uncertainties in
Age related distributive justice and claims on resources.
Irwin, S
1996-03-01
The ageing population structure, and claims on resources by non-working groups, are seen by many to be contributing to a growing welfare crisis. In their arguments, relations between age groups and generations will become increasingly fraught, and welfare arrangements will be undermined, as 'unacceptable' levels of taxation blight the experience of a contracting workforce, required to resource a growing welfare population. However, more seems to be known about researchers' views on distributive justice than is known about the perceptions of their subject populations. It has not been demonstrated that members of age groups share interests which are consonant with their cohort experience, or perceive their interests to be in conflict with those members of other age groups or generations. This paper analyses empirical evidence on people's perceptions of who should get, and do, what, in developing an argument that standard processes do not place age groups or generations in antagonistic relationship. Understanding the relations between age groups and generations is essential to explaining change in patterns of inequality, but the interdependence of these relations suggest that they are part of a coherent social structure, and not likely to give rise to crisis in the ways predicted.
Asquith, William H.
2014-01-01
The implementation characteristics of two method of L-moments (MLM) algorithms for parameter estimation of the 4-parameter Asymmetric Exponential Power (AEP4) distribution are studied using the R environment for statistical computing. The objective is to validate the algorithms for general application of the AEP4 using R. An algorithm was introduced in the original study of the L-moments for the AEP4. A second or alternative algorithm is shown to have a larger L-moment-parameter domain than the original. The alternative algorithm is shown to provide reliable parameter production and recovery of L-moments from fitted parameters. A proposal is made for AEP4 implementation in conjunction with the 4-parameter Kappa distribution to create a mixed-distribution framework encompassing the joint L-skew and L-kurtosis domains. The example application provides a demonstration of pertinent algorithms with L-moment statistics and two 4-parameter distributions (AEP4 and the Generalized Lambda) for MLM fitting to a modestly asymmetric and heavy-tailed dataset using R.
Distribution system water age can create premise plumbing corrosion hotspots.
Masters, Sheldon; Parks, Jeffrey; Atassi, Amrou; Edwards, Marc A
2015-09-01
Cumulative changes in chemical and biological properties associated with higher "water age" in distribution systems may impact water corrosivity and regulatory compliance with lead and copper action levels. The purpose of this study was to examine the effects of water age and chemistry on corrosivity of various downstream premise plumbing pipe materials and configurations using a combination of controlled laboratory studies and a field survey. Examination of lead pipe, copper pipe with lead solder, and leaded brass materials in a replicated lab rig simulating premise plumbing stagnation events indicated that lead or copper release could increase as much as ∼440 % or decrease as much as 98 % relative to water treatment plant effluent. In field studies at five utilities, trends in lead and copper release were highly dependent on circumstance; for example, lead release increased with water age in 13 % of cases and decreased with water age in 33 % of conditions tested. Levels of copper in the distribution system were up to 50 % lower and as much as 30 % higher relative to levels at the treatment plant. In many cases, high-risks of elevated lead and copper did not co-occur, demonstrating that these contaminants will have to be sampled separately to identify "worst case" conditions for human exposure and monitoring. PMID:26251058
Distribution system water age can create premise plumbing corrosion hotspots.
Masters, Sheldon; Parks, Jeffrey; Atassi, Amrou; Edwards, Marc A
2015-09-01
Cumulative changes in chemical and biological properties associated with higher "water age" in distribution systems may impact water corrosivity and regulatory compliance with lead and copper action levels. The purpose of this study was to examine the effects of water age and chemistry on corrosivity of various downstream premise plumbing pipe materials and configurations using a combination of controlled laboratory studies and a field survey. Examination of lead pipe, copper pipe with lead solder, and leaded brass materials in a replicated lab rig simulating premise plumbing stagnation events indicated that lead or copper release could increase as much as ∼440 % or decrease as much as 98 % relative to water treatment plant effluent. In field studies at five utilities, trends in lead and copper release were highly dependent on circumstance; for example, lead release increased with water age in 13 % of cases and decreased with water age in 33 % of conditions tested. Levels of copper in the distribution system were up to 50 % lower and as much as 30 % higher relative to levels at the treatment plant. In many cases, high-risks of elevated lead and copper did not co-occur, demonstrating that these contaminants will have to be sampled separately to identify "worst case" conditions for human exposure and monitoring.
Fundamental Parameters of Nearby Red Dwarfs: Stellar Radius as an Indicator of Age
NASA Astrophysics Data System (ADS)
Silverstein, Michele L.; Henry, Todd J.; Winters, Jennifer G.; Jao, Wei-Chun; Riedel, Adric R.; Dieterich, Sergio; RECONS Team
2016-01-01
Red dwarfs dominate the Galactic population, yet determining one of their most fundamental characteristics --- age --- has proven difficult. The characterization of red dwarfs in terms of their age is fundamental to mapping the history of star and, ultimately, planet formation in the Milky Way. Here we report on a compelling technique to evaluate the radii of red dwarfs, which can be used to provide leverage in estimating their ages. These radii are also particularly valuable in the cases of transiting exoplanet hosts because accurate stellar radii are required to determine accurate planetary radii.In this work, we use the BT-Settl models in combination with Johnson-Kron-Cousins VRI, 2MASS JHK, and WISE All-Sky Release photometry to produce spectral energy distributions (SEDs) to determine the temperatures and bolometric fluxes for 500 red dwarfs, most of which are in the southern sky. The full suites of our photometric and astrometric data (including hundreds of accurate new parallaxes from the RECONS team at the CTIO/SMARTS 0.9m) allow us to also determine the bolometric luminosities and radii. This method of radius determination is validated by a comparison of our measurements to those found using the CHARA Array (Boyajian et al. 2012), which match within a few percent.In addition to a compilation of red dwarf fundamental parameters, our findings provide a snapshot of relative stellar ages in the solar neighborhood. Of particular interest are the cohorts of very young and very old stars identified within 50 pc. These outliers exemplify the demographic extremes of the nearest stars.This effort has been supported by the NSF through grants AST-0908402, AST-1109445, and AST-1412026, and via observations made possible by the SMARTS Consortium.
Cubic spline approximation techniques for parameter estimation in distributed systems
NASA Technical Reports Server (NTRS)
Banks, H. T.; Crowley, J. M.; Kunisch, K.
1983-01-01
Approximation schemes employing cubic splines in the context of a linear semigroup framework are developed for both parabolic and hyperbolic second-order partial differential equation parameter estimation problems. Convergence results are established for problems with linear and nonlinear systems, and a summary of numerical experiments with the techniques proposed is given.
Estimation of Heterogeneity in Diagnostic Parameters of Age-related Diseases.
Blokh, David; Stambler, Ilia
2014-08-01
The heterogeneity of parameters is a ubiquitous biological phenomenon, with critical implications for biological systems functioning in normal and diseased states. We developed a method to estimate the level of objects set heterogeneity with reference to particular parameters and applied it to type II diabetes and heart disease, as examples of age-related systemic dysfunctions. The Friedman test was used to establish the existence of heterogeneity. The Newman-Keuls multiple comparison method was used to determine clusters. The normalized Shannon entropy was used to provide the quantitative evaluation of heterogeneity. There was obtained an estimate for the heterogeneity of the diagnostic parameters in healthy subjects, as well as in heart disease and type II diabetes patients, which was strongly related to their age. With aging, as with the diseases, the level of heterogeneity (entropy) was reduced, indicating a formal analogy between these phenomena. The similarity of the patterns in aging and disease suggested a kind of "early aging" of the diseased subjects, or alternatively a "disease-like" aging process, with reference to these particular parameters. The proposed method and its validation on the chronic age-related disease samples may support a way toward a formal mathematical relation between aging and chronic diseases and a formal definition of aging and disease, as determined by particular heterogeneity (entropy) changes. PMID:25110613
NASA Astrophysics Data System (ADS)
Åkesson, Maria; Suckow, Axel; Visser, Ate; Sültenfuβ, Jürgen; Laier, Troels; Purtschert, Roland; Sparrenbom, Charlotte J.
2015-09-01
Twenty-five public supply wells throughout the hydrogeologically diverse region of Scania, southern Sweden are subjected to environmental tracer analysis (3H-3He, 4He, CFCs, SF6 and for one well only also 85Kr and 39Ar) to study well and aquifer vulnerability and evaluate possibilities of groundwater age distribution assessment. We find CFC and SF6 concentrations well above solubility equilibrium with modern atmosphere, indicating local contamination, as well as indications of CFC degradation. The tracer-specific complications considerably constrain possibilities for sound quantitative regional groundwater age distribution assessments and demonstrate the importance of initial qualitative assessment of tracer-specific reliability, as well a need for additional, complementary tracers (e.g. 85Kr, 39Ar and potentially also 14C). Lumped parameter modelling yields credible age distribution assessments for representative wells in four type aquifers. Pollution vulnerability of the aquifer types was based on the selected LPM models and qualitative age characterisation. Most vulnerable are unconfined dual porosity and fractured bedrock aquifers, due to a large component of very young groundwater. Unconfined sedimentary aquifers are vulnerable due to young groundwater and a small pre-modern component. Less vulnerable are semi-confined sedimentary or dual-porosity aquifers, due to older age of the modern component and a larger pre-modern component. Confined aquifers appear least vulnerable, due an entirely pre-modern groundwater age distribution (recharged before 1963). Tracer complications aside, environmental tracer analyses and lumped parameter modelling aid in vulnerability assessment and protection of regional groundwater resources.
Scale Shrinkage and the Estimation of Latent Distribution Parameters.
ERIC Educational Resources Information Center
Camilli, Gregory
1988-01-01
The phenomenon of scale shrinkage is examined. Focus is on the pattern of decreasing variances in item response theory scale scores from fall to spring within a grade. It is demonstrated that questions concerning population distributions of true ability can be addressed with empirical Bayes techniques. (TJH)
Age changes in the distribution of visual attention.
McCalley, L T; Bouwhuis, D G; Juola, J F
1995-11-01
Two experiments examined adult age differences in the controlled allocation of visual selective attention. Both experiments were identical with the exception of the stimulus display where targets and distractors were linearly increased with eccentricity in Experiment 2. A spatial cuing task was used with four cue-target presentation intervals (SOAs) of 250, 500, 1000, and 2000 msec (Experiment 1) and 250, 500, 750, and 1000 msec (Experiment 2). Results were fit to three quantitative models based on attentional distribution metaphors (spotlight, zoom lens, and ring) in order to determine the best fitting model of attentional distribution. Data from Experiment 1 indicated that older subjects distributed attention in a qualitatively different manner than younger subjects and suggested a different time course of processing. When stimuli visibility was controlled a single flexible resource allocation (ring) model of attention could account for the results of both age groups at all SOAs. Results further suggested that older adults employ compensatory strategies to offset visual processing difficulties. PMID:7583811
Mass/age distribution of organic carbon for the Phanerozoic
Hay, W.W.; Wold, C.N. Geomar, Kiel )
1991-03-01
The mass/age distribution of organic carbon in Phanerozoic sedimentary rocks is dominated by disseminated organic carbon in pelitic rocks. Even during the major times of coal formation, the mass of organic carbon in coal is small compared with that included in fine-grained marine sediments. The mass/age distribution shows maxima in the Middle and Late Ordovician, Late Devonian, Late Jurassic and Early Cretaceous, and Neogene. Minima in accumulation of organic carbon mark the Early Ordovician, Early Devonian, Permian and Triassic, Late Cretaceous and Paleogene. Reconstruction of the ancient fluxes of organic carbon into the sediments shows that the distribution is almost symmetrical about the Paleozoic-Mesozoic boundary. Major hydrocarbon source rock accumulations coincide with peaks of organic carbon deposition, but modes of formation of the source rocks at each peak may have been different. The peaks of organic carbon accumulation correspond to times of flooding of the continents. The Ordovician, Late Jurassic-Early Cretaceous peaks also correspond to an increase in the ratio of carbon being deposited as organic carbon relative to that deposited as carbonate; they also correspond to times of deposition of large amounts of siliceous sediment. The Lake Devonian peak also formed at a time of flooding of the continents, but shows a low ratio of organic carbon to carbonate, and few siliceous rocks accumulated contemporaneously. The Neogene peak may represent a fundamentally different accumulation mechanism, resulting mostly from coastal upwelling during a time of emergence of the continents.
Computer-assisted sperm analysis parameters in young fertile sperm donors and relationship with age.
Fréour, Thomas; Jean, Miguel; Mirallie, Sophie; Barriere, Paul
2012-04-01
Sperm parameter values have been shown to decline with age, according to conventional sperm analysis. However, the effect of age on sperm kinematic parameters has been rarely studied, especially in young fertile men. Here, we studied Computer-Assisted Sperm Analysis (CASA) parameters in a large cohort of men with proven fertility, in order to determine if there is a decline with age in this young fertile population. This retrospective analysis of CASA parameters was conducted on all donors included in the sperm donor programme in the Assisted Reproductive Techniques (ART) Centre of the University Hospital of Nantes between 2006 and 2009. Sperm concentration, motility, and kinetic parameters were recorded by a HTM-Ceros system and compared in 3 groups of sperm donors according to their age: <35 years, 36-40 years, and 41-44 years. A total of 362 ejaculates from 138 donors were analyzed. Values for ALH, VCL, LIN, and STR significantly decreased with age. Sperm concentration, motile sperm proportion, and other kinetic parameters did not differ significantly among the groups. The use of CASA allowed the identification of ALH, VCL, LIN, and STR age-related decrease in young men with proven fertility.
Miller, G; Melo, D; Martz, H; Bertelli, L
2008-01-01
A simplified biokinetic model for (137)Cs has six parameters representing transfer of material to and from various compartments. Using a Bayesian analysis, the joint probability distribution of these six parameters is determined empirically for two cases with quite a lot of bioassay data. The distribution is found to be a multivariate log-normal. Correlations between different parameters are obtained. The method utilises a fairly large number of pre-determined forward biokinetic calculations, whose results are stored in interpolation tables. Four different methods to sample the multidimensional parameter space with a limited number of samples are investigated: random, stratified, Latin Hypercube sampling with a uniform distribution of parameters and importance sampling using a lognormal distribution that approximates the posterior distribution. The importance sampling method gives much smaller sampling uncertainty. No sampling method-dependent differences are perceptible for the uniform distribution methods. PMID:18420573
Sanford, W.E.; Deak, J.; Revesz, K.
2002-01-01
Parameter estimation was conducted on a groundwater model of the Danube-Tisza interfluvial region of Hungary. The model was calibrated using 300 water levels and 48 14C ages. The model provided a test of regression methods for a system with a large number of observations. Up to 103 parameters representing horizontal and vertical hydraulic conductivities and boundary conductances were assigned using point values and bilinear interpolation between points. The lowest errors were obtained using an iterative approach with groups of parameters, rather than estimating all of the parameters simultaneously. The model with 48 parameters yielded the lowest standard error of regression.
NASA Astrophysics Data System (ADS)
Potters, M. G.; Bombois, X.; Mansoori, M.; Van den Hof, Paul M. J.
2016-08-01
Estimation of physical parameters in dynamical systems driven by linear partial differential equations is an important problem. In this paper, we introduce the least costly experiment design framework for these systems. It enables parameter estimation with an accuracy that is specified by the experimenter prior to the identification experiment, while at the same time minimising the cost of the experiment. We show how to adapt the classical framework for these systems and take into account scaling and stability issues. We also introduce a progressive subdivision algorithm that further generalises the experiment design framework in the sense that it returns the lowest cost by finding the optimal input signal, and optimal sensor and actuator locations. Our methodology is then applied to a relevant problem in heat transfer studies: estimation of conductivity and diffusivity parameters in front-face experiments. We find good correspondence between numerical and theoretical results.
EM algorithm in estimating the 2- and 3-parameter Burr Type III distributions
NASA Astrophysics Data System (ADS)
Ismail, Nor Hidayah Binti; Khalid, Zarina Binti Mohd
2014-07-01
The Burr Type III distribution has been applied in the study of income, wage and wealth. It is suitable to fit lifetime data since it has flexible shape and controllable scale parameters. The popularity of Burr Type III distribution increases because it has included the characteristics of other distributions such as logistic and exponential. Burr Type III distribution has two categories: First a two-parameter distribution which has two shape parameters and second a three-parameter distribution which has a scale and two shape parameters. Expectation-maximization (EM) algorithm method is selected in this paper to estimate the two- and three-parameter Burr Type III distributions. Complete and censored data are simulated based on the derivation of pdf and cdf in parametric form of Burr Type III distributions. Then, the EM estimates are compared with estimates from maximum likelihood estimation (MLE) approach through mean square error. The best approach results in estimates with a higher approximation to the true parameters are determined. The result shows that the EM algorithm estimates perform better than the MLE estimates for two- and three-parameter Burr Type III distributions in the presence of complete and censored data.
Applications of computer algebra to distributed parameter systems
NASA Technical Reports Server (NTRS)
Storch, Joel A.
1993-01-01
In the analysis of vibrations of continuous elastic systems, one often encounters complicated transcendental equations with roots directly related to the system's natural frequencies. Typically, these equations contain system parameters whose values must be specified before a numerical solution can be obtained. The present paper presents a method whereby the fundamental frequency can be obtained in analytical form to any desired degree of accuracy. The method is based upon truncation of rapidly converging series involving inverse powers of the system natural frequencies. A straightforward method to developing these series and summing them in closed form is presented. It is demonstrated how Computer Algebra can be exploited to perform the intricate analytical procedures which otherwise would render the technique difficult to apply in practice. We illustrate the method by developing two analytical approximations to the fundamental frequency of a vibrating cantilever carrying a rigid tip body. The results are compared to the numerical solution of the exact (transcendental) frequency equation over a range of system parameters.
Automated CFD Parameter Studies on Distributed Parallel Computers
NASA Technical Reports Server (NTRS)
Rogers, Stuart E.; Aftosmis, Michael; Pandya, Shishir; Tejnil, Edward; Ahmad, Jasim; Kwak, Dochan (Technical Monitor)
2002-01-01
The objective of the current work is to build a prototype software system which will automated the process of running CFD jobs on Information Power Grid (IPG) resources. This system should remove the need for user monitoring and intervention of every single CFD job. It should enable the use of many different computers to populate a massive run matrix in the shortest time possible. Such a software system has been developed, and is known as the AeroDB script system. The approach taken for the development of AeroDB was to build several discrete modules. These include a database, a job-launcher module, a run-manager module to monitor each individual job, and a web-based user portal for monitoring of the progress of the parameter study. The details of the design of AeroDB are presented in the following section. The following section provides the results of a parameter study which was performed using AeroDB for the analysis of a reusable launch vehicle (RLV). The paper concludes with a section on the lessons learned in this effort, and ideas for future work in this area.
A lifetime of professional singing: Voice parameters and age in the Netherlands Radio Choir.
Berghs, Geert; Creylman, Nena; Avaux, Marianne; Decoster, Wivine; de Jong, Felix
2013-07-01
In professional choirs one would like to identify the incidence and severity of vocal problems due to ageing, and know how to influence them. The aim of the current study was to investigate to what extent easily obtainable voice parameters were age-related. From 47 singers of the Netherlands Radio Choir the Voice Range Profile parameters and the vibrato characteristics were measured. Dysphonia Severity Index (DSI) was calculated. We found that the age of male and female singers correlated negatively to the highest fundamental frequency and the Dysphonia Severity Index. No signs of slower and wider vibrato were found. These findings can lead to identifying adequate parameters e.g. for the ageing voice, useful in larger groups of professional singers. PMID:23116370
NASA Astrophysics Data System (ADS)
Rajkumar, K. V.; Vaidyanathan, S.; Kumar, Anish; Jayakumar, T.; Raj, Baldev; Ray, K. K.
2007-05-01
The best combinations of mechanical properties (yield stress and fracture toughness) of M250 maraging steel is obtained through short-term thermal aging (3-10 h) at 755 K. This is attributed to the microstructure containing precipitation of intermetallic phases in austenite-free low-carbon martensite matrix. Over-aged microstructure, containing reverted austenite degrades the mechanical properties drastically. Hence, it necessitates identification of a suitable non-destructive evaluation (NDE) technique for detecting any reverted austenite unambiguously during aging. The influence of aging on microstructure, room temperature hardness and non-destructive magnetic parameters such as coercivity ( Hc), saturation magnetization ( Ms) and magnetic Barkhausen emission (MBE) RMS peak voltage is studied in order to derive correlations between these parameters in aged M250 maraging steel. Hardness was found to increase with precipitation of intermetallics during initial aging and decrease at longer durations due to austenite reversion. Among the different magnetic parameters studied, MBE RMS peak voltage was found to be very sensitive to austenite reversion (non-magnetic phase) as they decreased drastically up on initiation of austenite reversion. Hence, this parameter can be effectively utilized to detect and quantify the reverted austenite in maraging steel specimen. The present study clearly indicates that the combination of MBE RMS peak voltage and hardness can be used for unambiguous characterization of microstructural features of technological and practical importance (3-10 h of aging duration at 755 K) in M250 grade maraging steel.
Parameter sensitivity study of Arctic aerosol vertical distribution in CAM5
NASA Astrophysics Data System (ADS)
Jiao, C.; Flanner, M.
2015-12-01
Arctic surface temperature response to light-absorbing aerosols (black carbon, brown carbon and dust) depends strongly on their vertical distributions. Improving model simulations of three dimensional aerosol fields in the remote Arctic region will therefore lead to improved projections of the climate change caused by aerosol emissions. In this study, we investigate how different physical parameterizations in the Community Atmosphere Model version 5 (CAM5) influence the simulated vertical distribution of Arctic aerosols. We design experiments to test the sensitivity of the simulated aerosol fields to perturbations of selected aerosol process-related parameters in the Modal Aerosol Module with seven lognormal modes (MAM7), such as those govern aerosol aging, in-cloud and below-cloud scavenging, aerosol hygroscopicity and so on. The simulations are compared with observed aerosol vertical distributions and total optical depth to assess model performance and quantify uncertainties associated with these model parameterizations. Observations applied here include Arctic aircraft measurements of black carbon and sulfate vertical profiles, along with Aerosol Robotic Network (AERONET) optical depth measurements. We also assess the utility of using High Spectral Resolution Lidar (HSRL) measurements from the ARM Barrow site to infer vertical profiles of aerosol extinction. The sensitivity study explored here will provide guidance for optimizing global aerosol simulations.
NASA Astrophysics Data System (ADS)
Cornaton, F. J.
2012-03-01
Environmental fluid circulations are very often characterized by analyzing the fate and behavior of natural and anthropogenic tracers. Among these tracers, age is taken as an ideal tracer which can yield interesting diagnoses, as for example the characterization of the mixing and renewal of water masses, of the fate and mixing of contaminants, or the calibration of hydrodispersive parameters used by numerical models. Such diagnoses are of great interest in atmospheric and ocean circulation sciences, as well in surface and subsurface hydrology. The temporal evolution of groundwater age and its frequency distributions can display important changes as flow regimes vary due to natural change in climate and hydrologic conditions and/or human induced pressures on the resource to satisfy the water demand. Groundwater age being nowadays frequently used to investigate reservoir properties and recharge conditions, special attention needs to be put on the way this property is characterized, would it be using isotopic methods or mathematical modeling. Steady state age frequency distributions can be modeled using standard numerical techniques since the general balance equation describing age transport under steady state flow conditions is exactly equivalent to a standard advection-dispersion equation. The time-dependent problem is however described by an extended transport operator that incorporates an additional coordinate for water age. The consequence is that numerical solutions can hardly be achieved, especially for real 3-D applications over large time periods of interest. A novel algorithm for solving the age distribution problem under time-varying flow regimes is presented and, for some specific configurations, extended to the problem of generalized component exposure time. The algorithm combines the Laplace transform technique applied to the age (or exposure time) coordinate with standard time-marching schemes. The method is validated and illustrated using analytical
Jurgens, Bryant C.; Böhlke, J.K.; Eberts, Sandra M.
2012-01-01
TracerLPM is an interactive Excel® (2007 or later) workbook program for evaluating groundwater age distributions from environmental tracer data by using lumped parameter models (LPMs). Lumped parameter models are mathematical models of transport based on simplified aquifer geometry and flow configurations that account for effects of hydrodynamic dispersion or mixing within the aquifer, well bore, or discharge area. Five primary LPMs are included in the workbook: piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM), partial exponential model (PEM), and dispersion model (DM). Binary mixing models (BMM) can be created by combining primary LPMs in various combinations. Travel time through the unsaturated zone can be included as an additional parameter. TracerLPM also allows users to enter age distributions determined from other methods, such as particle tracking results from numerical groundwater-flow models or from other LPMs not included in this program. Tracers of both young groundwater (anthropogenic atmospheric gases and isotopic substances indicating post-1940s recharge) and much older groundwater (carbon-14 and helium-4) can be interpreted simultaneously so that estimates of the groundwater age distribution for samples with a wide range of ages can be constrained. TracerLPM is organized to permit a comprehensive interpretive approach consisting of hydrogeologic conceptualization, visual examination of data and models, and best-fit parameter estimation. Groundwater age distributions can be evaluated by comparing measured and modeled tracer concentrations in two ways: (1) multiple tracers analyzed simultaneously can be evaluated against each other for concordance with modeled concentrations (tracer-tracer application) or (2) tracer time-series data can be evaluated for concordance with modeled trends (tracer-time application). Groundwater-age estimates can also be obtained for samples with a single tracer measurement at one
Reliability analysis of structural ceramic components using a three-parameter Weibull distribution
NASA Technical Reports Server (NTRS)
Duffy, Stephen F.; Powers, Lynn M.; Starlinger, Alois
1992-01-01
Described here are nonlinear regression estimators for the three-parameter Weibull distribution. Issues relating to the bias and invariance associated with these estimators are examined numerically using Monte Carlo simulation methods. The estimators were used to extract parameters from sintered silicon nitride failure data. A reliability analysis was performed on a turbopump blade utilizing the three-parameter Weibull distribution and the estimates from the sintered silicon nitride data.
A comparative study of ballpoint ink ageing parameters using GC/MS.
Koenig, Agnès; Magnolon, Sophie; Weyermann, Céline
2015-07-01
For more than a decade scientists tried to develop methods capable of dating ink by monitoring the loss of phenoxyethanol (PE) over time. While many methods were proposed in the literature, few were really used to solve practical cases and they still raise much concern within the scientific community. In fact, due to the complexity of ink drying processes it is particularly difficult to find a reliable ageing parameter to reproducibly follow ink ageing. Moreover, systematic experiments are required in order to evaluate how different factors actually influence the results over time. Therefore, this work aimed at evaluating the capacity of four different ageing parameters to reliably follow ink ageing over time: (1) the quantity of solvent PE in an ink line, (2) the relative peak area (RPA) normalising the PE results using stable volatile compounds present in the ink formulation, (3) the solvent loss ratio (R%) calculated from PE results obtained by the analyses of naturally and artificially aged samples, (4) a modified solvent loss ratio version (R%*) calculated from RPA results. After the determination of the limits of reliable measurements of the analytical method, the repeatability of the different ageing parameters was evaluated over time, as well as the influence of ink composition, writing pressure and storage conditions on the results. Surprisingly, our results showed that R% was not the most reliable parameter, as it showed the highest standard deviation. Discussion of the results in an ink dating perspective suggests that other proposed parameters, such as RPA values, may be more adequate to follow ink ageing over time.
NASA Astrophysics Data System (ADS)
Edouard, C.; Petit, M.; Forgez, C.; Bernard, J.; Revel, R.
2016-09-01
In this work, a simplified electrochemical and thermal model that can predict both physicochemical and aging behavior of Li-ion batteries is studied. A sensitivity analysis of all its physical parameters is performed in order to find out their influence on the model output based on simulations under various conditions. The results gave hints on whether a parameter needs particular attention when measured or identified and on the conditions (e.g. temperature, discharge rate) under which it is the most sensitive. A specific simulation profile is designed for parameters involved in aging equations in order to determine their sensitivity. Finally, a step-wise method is followed to limit the influence of parameter values when identifying some of them, according to their relative sensitivity from the study. This sensitivity analysis and the subsequent step-wise identification method show very good results, such as a better fitting of the simulated cell voltage with experimental data.
Czuba, M.; Komsta-Szumska, E.; Mortimer, D.C.; Champagne, C.
1987-03-01
The influence of diet is recognized as a significant factor in the expression of toxicity. This applies particularly to toxins like methylmercury (MeHg) which are metabolically incorporated into growing food plants and biotransformed within the plant before ingestion. Methylmercury in this form may influence the early physiological and biochemical events which lead to development of toxicity. In a previous study, a single dose of plant-incorporated methylmercury (MeHg) had a different route of distribution and accumulation in rat organs after 48 h than an equivalent dose of saline MeHg with the greatest accumulation being in red blood cells. Creatine, an important storage form of high energy phosphate in muscles is a primary indicator of erythropoietic dynamics under hypoxia, a sensitive indicator of hemolytic disease, red blood cell aging and impaired marrow efficiency. Since changes in creatine levels occur sooner than changes in other blood parameters, itself being neither synthesized nor metabolized by red blood cells, it can be used as a sensitive indicator of toxicity. The present work investigates the difference in a longer term, multiple-dose regime of saline or bean-incorporated MeHg ingestion with special attention being given to various blood parameters.
Fast Airborne Size Distribution Measurements of an Aerosol Processes and Aging
NASA Astrophysics Data System (ADS)
Kapustin, V.; Clarke, A. D.; Zhou, J.; Brekhovskikh, V.; McNaughton, C. S.; Howell, S.
2009-12-01
During MILAGRO/INTEX experiment the Hawaii Group for Environmental Aerosol Research (HIGEAR) deployed a wide range of aerosol instrumentation aboard NSF C-130 and NASA DC-8. These were designed to provide rapid information on aerosol composition, state of mixing (internal or external), spectral optical properties (scattering and absorption), the humidity dependence of light scattering - f(RH), and the role of condensed species in changing the absorption properties of black carbon (BC) and inferred properties of organic carbon (OC). We also flew the Fast Mobility Particle Spectrometer (FMPS, TSI Inc.) to measure aerosol size distributions in a range 5.6 - 560 nm. For all our flights around Mexico City, an aerosol number concentration usually was well above the nominal FMPS sensitivity (from ~100 particles/cc @ Dp = 5.6 nm to 1 part/cc @ 560nm), providing us with reliable size distributions even at 1 sec resolution. FMPS measurements revealed small scale structure of an aerosol and allowed us to examine size distributions varying over space and time associated with mixing processes previously unresolved. These 1-Hz measurements during aircraft profiles captured variations in size distributions within shallow layers. Other dynamic processes observed included orography induced aerosol layers and evolution of the nanoparticles formed by nucleation. We put FMPS high resolution size distribution data in a context of aerosol evolution and aging, using a range of established (for MIRAGE/INTEX) chemical, aerosol and transport aging parameters.
Bullock, Meggan; Márquez, Lourdes; Hernández, Patricia; Ruíz, Fernando
2013-09-01
Traditional methods of aging adult skeletons suffer from the problem of age mimicry of the reference collection, as described by Bocquet-Appel and Masset (1982). Transition analysis (Boldsen et al., 2002) is a method of aging adult skeletons that addresses the problem of age mimicry of the reference collection by allowing users to select an appropriate prior probability. In order to evaluate whether transition analysis results in significantly different age estimates for adults, the method was applied to skeletal collections from Postclassic Cholula and Contact-Period Xochimilco. The resulting age-at-death distributions were then compared with age-at-death distributions for the two populations constructed using traditional aging methods. Although the traditional aging methods result in age-at-death distributions with high young adult mortality and few individuals living past the age of 50, the age-at-death distributions constructed using transition analysis indicate that most individuals who lived into adulthood lived past the age of 50.
Frequency distributions and correlations of solar X-ray flare parameters
NASA Technical Reports Server (NTRS)
Crosby, Norma B.; Aschwanden, Markus J.; Dennis, Brian R.
1993-01-01
Frequency distributions of flare parameters are determined from over 12,000 solar flares. The flare duration, the peak counting rate, the peak hard X-ray flux, the total energy in electrons, and the peak energy flux in electrons are among the parameters studied. Linear regression fits, as well as the slopes of the frequency distributions, are used to determine the correlations between these parameters. The relationship between the variations of the frequency distributions and the solar activity cycle is also investigated. Theoretical models for the frequency distribution of flare parameters are dependent on the probability of flaring and the temporal evolution of the flare energy build-up. The results of this study are consistent with stochastic flaring and exponential energy build-up. The average build-up time constant is found to be 0.5 times the mean time between flares.
PERFORMANCE VERIFICATION OF CONTINUOUS MULTI-PARAMETER WATER MONITORS FOR DISTRIBUTION SYSTEMS
The Environmental Technology Verification (ETV) Program's Advanced Monitoring Systems (AMS) Center has been charged by EPA to verify the performance of commercially available monitoring technologies for air, water, soil. Multi-parameter water monitors for distributions systems we...
Influence of emphysema distribution on pulmonary function parameters in COPD patients
Bastos, Helder Novais e; Neves, Inês; Redondo, Margarida; Cunha, Rui; Pereira, José Miguel; Magalhães, Adriana; Fernandes, Gabriela
2015-01-01
ABSTRACT OBJECTIVE: To evaluate the impact that the distribution of emphysema has on clinical and functional severity in patients with COPD. METHODS: The distribution of the emphysema was analyzed in COPD patients, who were classified according to a 5-point visual classification system of lung CT findings. We assessed the influence of emphysema distribution type on the clinical and functional presentation of COPD. We also evaluated hypoxemia after the six-minute walk test (6MWT) and determined the six-minute walk distance (6MWD). RESULTS: Eighty-six patients were included. The mean age was 65.2 ± 12.2 years, 91.9% were male, and all but one were smokers (mean smoking history, 62.7 ± 38.4 pack-years). The emphysema distribution was categorized as obviously upper lung-predominant (type 1), in 36.0% of the patients; slightly upper lung-predominant (type 2), in 25.6%; homogeneous between the upper and lower lung (type 3), in 16.3%; and slightly lower lung-predominant (type 4), in 22.1%. Type 2 emphysema distribution was associated with lower FEV1, FVC, FEV1/FVC ratio, and DLCO. In comparison with the type 1 patients, the type 4 patients were more likely to have an FEV1 < 65% of the predicted value (OR = 6.91, 95% CI: 1.43-33.45; p = 0.016), a 6MWD < 350 m (OR = 6.36, 95% CI: 1.26-32.18; p = 0.025), and post-6MWT hypoxemia (OR = 32.66, 95% CI: 3.26-326.84; p = 0.003). The type 3 patients had a higher RV/TLC ratio, although the difference was not significant. CONCLUSIONS: The severity of COPD appears to be greater in type 4 patients, and type 3 patients tend to have greater hyperinflation. The distribution of emphysema could have a major impact on functional parameters and should be considered in the evaluation of COPD patients. PMID:26785956
Age-related alterations to immune parameters in Labrador retriever dogs.
Blount, Daniel G; Pritchard, David I; Heaton, Paul R
2005-12-15
In order to assess age-related changes in the immune status of Labrador retriever dogs, leukocyte phenotypes, lymphocyte proliferative capacity, and serum antibody levels were measured in four cohorts of dogs, ranging from 2 to 10 years of age. Absolute numbers of white blood cells, lymphocytes, monocytes, granulocytes, and CD3+, CD4+, CD8+ and CD21+ lymphocytes significantly decreased with increasing age. Relative percentages of lymphocytes and CD4 cells were significantly decreased, and relative percentages of granulocytes and CD8 cells significantly increased, with age. The CD4:CD8 ratio showed a significant age-related decrease. Proliferative responses of T-cells to mitogens in whole-blood cultures either increased (Concanavalin A) or remained the same (phytohemagglutinin) with age when data was normalised to allow for differences in responding cell number. Similarly, normalised data of proliferative response to anti-CD3 stimulation together with phorbol 12-myristate 13-acetate showed an age-related increase. Serum levels of total IgA significantly increased with age whereas total IgG levels remained unchanged. These observations illustrate a significant change to a number of immune parameters with age. However, further work is required to determine whether the differences reported here are sufficient to cause overt or functional immune senescence in Labrador retriever dogs. PMID:16105688
ERIC Educational Resources Information Center
Kumari, Neeraj
2014-01-01
The objective of the study is to examine the students' perspective (age wise, gender wise and year wise) of parameters affecting the undergraduate engineering education system present in a private technical institution in NCR [National Capital Region], Haryana. It is a descriptive type of research in nature. The data has been collected with the…
Reliability analysis of structural ceramic components using a three-parameter Weibull distribution
NASA Technical Reports Server (NTRS)
Duffy, Stephen F.; Powers, Lynn M.; Starlinger, Alois
1992-01-01
Described here are nonlinear regression estimators for the three-Weibull distribution. Issues relating to the bias and invariance associated with these estimators are examined numerically using Monte Carlo simulation methods. The estimators were used to extract parameters from sintered silicon nitride failure data. A reliability analysis was performed on a turbopump blade utilizing the three-parameter Weibull distribution and the estimates from the sintered silicon nitride data.
The role of a roughness scaling parameter in describing alpine snow distribution (Invited)
NASA Astrophysics Data System (ADS)
Lehning, M.; Grünewald, T.; Schirmer, M.
2010-12-01
The mountain snow distribution affects not only the storage of snow water and avalanche danger but also the local conditions for plant and animal life. The snow distribution in the alpine zone is shaped by a general altitudinal gradient of precipitation, the locally varying deposition of snow and subsequent redistribution processes due to wind but also to snow slides. While progress has been made in understanding of processes involved in snow distribution, it has not been possible to satisfactorily predict snow distribution on the basis of local terrain parameters. We use a unique data set of high resolution snow depth measurements from an airborne laser scanner in two small mountain catchments to predict mean snow depth in topographic control units as a function of two terrain parameters: the conventional altitudinal gradient plus a new fractal roughness parameter. The analysis showed that heterogeneous snow distribution can be captured by merely analysing the terrain and the mean precipitation.
Variations of immune parameters in terrestrial isopods: a matter of gender, aging and Wolbachia
NASA Astrophysics Data System (ADS)
Sicard, Mathieu; Chevalier, Frédéric; de Vlechouver, Mickaël; Bouchon, Didier; Grève, Pierre; Braquart-Varnier, Christine
2010-09-01
Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a growing core of data put in light that vertically transmitted symbionts can dramatically modulate the immunocompetence of their hosts. In this study, we addressed the influence of gender, age and the feminising endosymbiont Wolbachia ( wVulC) on variations in haemocyte density, total PO activity and bacterial load in the haemolymph of the terrestrial isopod Armadillidium vulgare. This host-symbiont system is of particular interest to address this question since: (1) wVulC was previously shown as immunosuppressive in middle-aged females and (2) wVulC influences sex determination. We show that age, gender and Wolbachia modulate together immune parameters in A. vulgare. However, wVulC, which interacts with aging, appears to be the prominent factor interfering with both PO activity and haemocyte density. This interference with immune parameters is not the only aspect of wVulC virulence on its host, as reproduction and survival are also altered.
Variations of immune parameters in terrestrial isopods: a matter of gender, aging and Wolbachia.
Sicard, Mathieu; Chevalier, Frédéric; De Vlechouver, Mickaël; Bouchon, Didier; Grève, Pierre; Braquart-Varnier, Christine
2010-09-01
Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a growing core of data put in light that vertically transmitted symbionts can dramatically modulate the immunocompetence of their hosts. In this study, we addressed the influence of gender, age and the feminising endosymbiont Wolbachia (wVulC) on variations in haemocyte density, total PO activity and bacterial load in the haemolymph of the terrestrial isopod Armadillidium vulgare. This host-symbiont system is of particular interest to address this question since: (1) wVulC was previously shown as immunosuppressive in middle-aged females and (2) wVulC influences sex determination. We show that age, gender and Wolbachia modulate together immune parameters in A. vulgare. However, wVulC, which interacts with aging, appears to be the prominent factor interfering with both PO activity and haemocyte density. This interference with immune parameters is not the only aspect of wVulC virulence on its host, as reproduction and survival are also altered. PMID:20676599
Variations of immune parameters in terrestrial isopods: a matter of gender, aging and Wolbachia.
Sicard, Mathieu; Chevalier, Frédéric; De Vlechouver, Mickaël; Bouchon, Didier; Grève, Pierre; Braquart-Varnier, Christine
2010-09-01
Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a growing core of data put in light that vertically transmitted symbionts can dramatically modulate the immunocompetence of their hosts. In this study, we addressed the influence of gender, age and the feminising endosymbiont Wolbachia (wVulC) on variations in haemocyte density, total PO activity and bacterial load in the haemolymph of the terrestrial isopod Armadillidium vulgare. This host-symbiont system is of particular interest to address this question since: (1) wVulC was previously shown as immunosuppressive in middle-aged females and (2) wVulC influences sex determination. We show that age, gender and Wolbachia modulate together immune parameters in A. vulgare. However, wVulC, which interacts with aging, appears to be the prominent factor interfering with both PO activity and haemocyte density. This interference with immune parameters is not the only aspect of wVulC virulence on its host, as reproduction and survival are also altered.
Park, Yoon Soo; Lee, Young-Sun; Xing, Kuan
2016-01-01
This study investigates the impact of item parameter drift (IPD) on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT) models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS) were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results also showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effects on item parameters and examinee ability. PMID:26941699
Park, Yoon Soo; Lee, Young-Sun; Xing, Kuan
2016-01-01
This study investigates the impact of item parameter drift (IPD) on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT) models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS) were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results also showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effects on item parameters and examinee ability.
Three-parameter discontinuous distributions for hydrological samples with zero values
NASA Astrophysics Data System (ADS)
Weglarczyk, Stanislaw; Strupczewski, Witold G.; Singh, Vijay P.
2005-10-01
A consistent approach to the frequency analysis of hydrologic data in arid and semiarid regions, i.e. the data series containing several zero values (e.g. monthly precipitation in dry seasons, annual peak flow discharges, etc.), requires using discontinuous probability distribution functions. Such an approach has received relatively limited attention. Along the lines of physically based models, the extensions of the Muskingum-based models to three parameter forms are considered. Using 44 peak flow series from the USGS data bank, the fitting ability of four three-parameter models was investigated: (1) the Dirac delta combined with Gamma distribution; (2) the Dirac delta combined with two-parameter generalized Pareto distribution; (3) the Dirac delta combined with two-parameter Weibull (DWe) distribution; (4) the kinematic diffusion with one additional parameter that controls the probability of the zero event (KD3). The goodness of fit of the models was assessed and compared both by evaluation of discrepancies between the results of both estimation methods (i.e. the method of moments (MOM) and the maximum likelihood method (MLM)) and using the log of likelihood function as a criterion. In most cases, the DWe distribution with MLM-estimated parameters showed the best fit of all the three-parameter models.
da LUZ, Patrícia Aparecida Cardoso; SANTOS, Paulo Ramos da Silva; ANDRIGHETTO, Cristiana; JORGE, André Mendes; de ASSIS NETO, Antônio Chaves
2012-01-01
Abstract Buffalo are an economically important source for meat and milk production, especially in Brazil. However, important aspects of their biology remain unknown thus far. Herein, we describe the reproductive characteristics of male Murrah buffalo (Bubalus bubalis) raised under extensive management conditions by applying biometrics associated with testicular weight. We analyzed seven males, divided into two groups: G1, which consisted of four 18-month-old animals, and G2, which consisted of three 24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a delay of sexual maturity. The biometric testicular parameters analyzed were scrotal circumference, testicular weight, testicular length, testicular width, testicular thickness and testicular circumference. Our data indicate strong correlations between SC, age and body weight, and additional significant relationships were identified between body weight, age and other testicular parameters. Thus, these parameters are suitable indicators when selecting bulls for breeding purposes. PMID:22986925
da Luz, Patrícia Aparecida Cardoso; Santos, Paulo Ramos da Silva; Andrighetto, Cristiana; Jorge, André Mendes; de Assis Neto, Antônio Chaves
2013-01-01
Buffalo are an economically important source for meat and milk production, especially in Brazil. However, important aspects of their biology remain unknown thus far. Herein, we describe the reproductive characteristics of male Murrah buffalo (Bubalus bubalis) raised under extensive management conditions by applying biometrics associated with testicular weight. We analyzed seven males, divided into two groups: G1, which consisted of four 18-month-old animals, and G2, which consisted of three 24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a delay of sexual maturity. The biometric testicular parameters analyzed were scrotal circumference, testicular weight, testicular length, testicular width, testicular thickness and testicular circumference. Our data indicate strong correlations between SC, age and body weight, and additional significant relationships were identified between body weight, age and other testicular parameters. Thus, these parameters are suitable indicators when selecting bulls for breeding purposes. PMID:22986925
Effect of age, anthropometry, and distance in stroke parameters of young swimmers.
Mezzaroba, Paulo V; Machado, Fabiana A
2014-07-01
This study aimed to determine the influence of age, anthropometry, and distance on stroke parameters of 10- to 17-y-old swimmers. Forty-six male swimmers were divided into 4 chronological age groups. Anthropometry and sexual maturity were assessed, and maximal efforts of 100, 200, and 400 m using front-crawl style were performed to determine stroke rate (SR), length (SL), and index (SI). Multiple linear regression, 1-way, and mixed ANOVA for repeated measures were used for statistical analyses. There was significant effect of distance for all stroke parameters (P < .001) and an age effect only for SL and SI (P < .001). Post hoc showed that the 10- to 17-year-old group significantly reduced SR with increasing distance (effect size -0.8 to -1.5 comparing 100, 200, and 400 m) but were not effective in offsetting this adaptation with increased SL, especially from 200- to 400-m distance, at which no group made both adjustments, highlighting the decreased efficiency with significant SI reduction (effect size -0.2 to -0.4 comparing 100, 200, and 400 m). Considering all stroke parameters, the performances were almost 100% explained, but SI itself could explain around 90% of the performance; furthermore, limb length contributed to explain all stroke parameter, and SI was the variable best predicted (around 75%) by anthropometrical (upper limbs and height) and descriptive variables (age and y of systematic training).Thus, distinct effects of distance and advancing age were found during childhood and adolescence on stroke parameters, and SI was highlighted as the best predictor of 100-, 200-, and 400-m maximal performances.
Spatial variability of the parameters of a semi-distributed hydrological model
NASA Astrophysics Data System (ADS)
de Lavenne, Alban; Thirel, Guillaume; Andréassian, Vazken; Perrin, Charles; Ramos, Maria-Helena
2016-05-01
Ideally, semi-distributed hydrologic models should provide better streamflow simulations than lumped models, along with spatially-relevant water resources management solutions. However, the spatial distribution of model parameters raises issues related to the calibration strategy and to the identifiability of the parameters. To analyse these issues, we propose to base the evaluation of a semi-distributed model not only on its performance at streamflow gauging stations, but also on the spatial and temporal pattern of the optimised value of its parameters. We implemented calibration over 21 rolling periods and 64 catchments, and we analysed how well each parameter is identified in time and space. Performance and parameter identifiability are analysed comparatively to the calibration of the lumped version of the same model. We show that the semi-distributed model faces more difficulties to identify stable optimal parameter sets. The main difficulty lies in the identification of the parameters responsible for the closure of the water balance (i.e. for the particular model investigated, the intercatchment groundwater flow parameter).
Climatic influence on demographic parameters of a tropical seabird varies with age and sex.
Oro, Daniel; Torres, Roxana; Rodríguez, Cristina; Drummond, Hugh
2010-04-01
In marine ecosystems climatic fluctuation and other physical variables greatly influence population dynamics, but differential effects of physical variables on the demographic parameters of the two sexes and different age classes are largely unexplored. We analyzed the effects of climate on the survival and recruitment of both sexes and several age classes of a long-lived tropical seabird, the Blue-footed Booby (Sula nebouxii), using long-term observations on marked individuals. Results demonstrated a complex interaction between yearly fluctuations in climate (both local and global indexes, during both winter and breeding season) and the sex and age of individuals. Youngest birds' survival and recruitment were commonly affected by local climate, whereas oldest birds' parameters tended to be constant and less influenced by environmental variables. These results confirm the theoretical prediction that sex- and age-related variation in life-history demographic traits is greater under poor environmental conditions, and they highlight the importance of including variability in fitness components in demographic and evolutionary models. Males and females showed similar variation in survival but different recruitment patterns, in relation to both age and the spatial scale of climatic influence (local or global). Results indicate different life-history tactics for each sex and different ages, with birds likely trying to maximize their fitness by responding to the environmental contingencies of each year.
Climatic influence on demographic parameters of a tropical seabird varies with age and sex.
Oro, Daniel; Torres, Roxana; Rodríguez, Cristina; Drummond, Hugh
2010-04-01
In marine ecosystems climatic fluctuation and other physical variables greatly influence population dynamics, but differential effects of physical variables on the demographic parameters of the two sexes and different age classes are largely unexplored. We analyzed the effects of climate on the survival and recruitment of both sexes and several age classes of a long-lived tropical seabird, the Blue-footed Booby (Sula nebouxii), using long-term observations on marked individuals. Results demonstrated a complex interaction between yearly fluctuations in climate (both local and global indexes, during both winter and breeding season) and the sex and age of individuals. Youngest birds' survival and recruitment were commonly affected by local climate, whereas oldest birds' parameters tended to be constant and less influenced by environmental variables. These results confirm the theoretical prediction that sex- and age-related variation in life-history demographic traits is greater under poor environmental conditions, and they highlight the importance of including variability in fitness components in demographic and evolutionary models. Males and females showed similar variation in survival but different recruitment patterns, in relation to both age and the spatial scale of climatic influence (local or global). Results indicate different life-history tactics for each sex and different ages, with birds likely trying to maximize their fitness by responding to the environmental contingencies of each year. PMID:20462134
Martian channels and valleys - Their characteristics, distribution, and age
NASA Technical Reports Server (NTRS)
Carr, M. H.; Clow, G. D.
1981-01-01
The distribution and ages of Martian channels and valleys, which are generally believed to have been cut by running water, are examined with particular emphasis on the small branching networks referred to as runoff channels or valley networks. Valleys at latitudes from 65 deg S to 65 deg N were surveyed on Viking images at resolutions between 125 and 300 m. Almost all of the valleys are found in the old cratered terrain, in areas characterized by high elevations, low albedos and low violet/red ratios. The networks are deduced to have formed early in the history of the planet, with a formation rate declining rapidly shortly after the decline of the cratering rate 3.9 billion years ago. Two types of outflow channels are distinguished: unconfined, in which broad swaths of terrain are scoured, and confined, in which flow is restricted to discrete channels. Both types start at local sources, and have formed episodically throughout Martian history. Fretted channels, found mainly in two latitude belts characterized by relatively rapid erosion along escarpments, are explained by the lateral enlargement of other channels by mass wasting.
Myrhaug, D. . Dept. of Marine Hydrodynamics); Rue, H. . Division of Industrial Mathematics)
1993-08-01
In this paper, a joint distribution of wave steepness parameters for two successive waves is presented. The wave steepness parameters considered herein are the crest front steepness and the total wave steepness. The joint distribution of wave steepness parameters for two successive waves is represented by a two-dimensional Weibull distribution with the parameters [alpha]=0.84 and [beta]=1.40. The application of the results is illustrated by an example. Overall these results seem to be physically sound, although they are valid for the particular sea state chosen. The present approach has some basis in measured wave data, but comparison with data on the joint distribution of steepness parameters for two successive waves are needed before any conclusion can be drawn on the ability of this approach to describe measured wave data. Such a data base should be established from carefully designed field measurements in order to have the possibility to measure nonlinear properties of the waves. However, at present this joint distribution of steepness parameters for two successive waves should represent a useful tool for engineering applications.
Estimating the distribution of radionuclides in agricultural soils - dependence on soil parameters.
Hormann, Volker; Fischer, Helmut W
2013-10-01
In this study it is shown how radionuclide distributions in agricultural soils and their dependence on soil parameters can be quantitatively estimated. The most important sorption and speciation processes have been implemented into a numerical model using the geochemical code PHREEQC that is able to include specific soil and soil solution compositions. Using this model, distribution coefficients (Kd values) for the elements Cs, Ni, U and Se have been calculated for two different soil types. Furthermore, the dependencies of these Kd values on various soil parameters (e.g. pH value or organic matter content) have been evaluated. It is shown that for each element, an individual set of soil parameters is relevant for its solid-liquid distribution. The model may be used for the calculation of input parameters used by reference biosphere models (e.g. used for the risk assessment of nuclear waste repositories). PMID:23871968
Estimating the distribution of radionuclides in agricultural soils - dependence on soil parameters.
Hormann, Volker; Fischer, Helmut W
2013-10-01
In this study it is shown how radionuclide distributions in agricultural soils and their dependence on soil parameters can be quantitatively estimated. The most important sorption and speciation processes have been implemented into a numerical model using the geochemical code PHREEQC that is able to include specific soil and soil solution compositions. Using this model, distribution coefficients (Kd values) for the elements Cs, Ni, U and Se have been calculated for two different soil types. Furthermore, the dependencies of these Kd values on various soil parameters (e.g. pH value or organic matter content) have been evaluated. It is shown that for each element, an individual set of soil parameters is relevant for its solid-liquid distribution. The model may be used for the calculation of input parameters used by reference biosphere models (e.g. used for the risk assessment of nuclear waste repositories).
Fetal kidney length as a useful adjunct parameter for better determination of gestational age
Ugur, Mete G.; Mustafa, Aynur; Ozcan, Huseyin C.; Tepe, Neslihan B.; Kurt, Huseyin; Akcil, Emre; Gunduz, Reyhan
2016-01-01
Objectives: To determine the validity of fetal kidney length and amniotic fluid index (AFI) in labor dating. Methods: This prospective study included 180 pregnant women followed up in the outpatient clinic at the Department of Obstetrics and Gynecology, Gaziantep University, Turkey, between January 2014 and January 2015. The gestational age (GA) was estimated by early fetal ultrasound measures and last menstrual period. Routine fetal biometric parameters, fetal kidney length, and amniotic fluid index were measured. We studied the correlation between fetal kidney length, amniotic fluid index, and gestational age. Result: The mean gestational age depending on last menstrual period and early ultrasound was 31.98±4.29 (24-39 weeks). The mean kidney length was 35.66±6.61 (19-49 mm). There was a significant correlation between gestational age and fetal kidney length (r=0.947, p=0.001). However, there was a moderate negative correlation between GA and AFI. Adding fetal kidney length to the routine biometrics improved the effectiveness of the model used to estimate GA (R2=0.965 to R2=0.987). Conclusion: Gestational age can be better predicted by adding fetal kidney length to other routine parameters. PMID:27146616
The effect of age on pressure flow parameters in women with lower urinary tract symptoms.
Basu, M; Postlethwaite, C; Cheema, K; Duckett, J
2013-11-01
This study aimed to evaluate changes in voiding with age in women with different urodynamic diagnoses. Correlation was used to analyse the association between age and voiding parameters (maximum flow rate, voided volume, flow rate centile and maximum detrusor pressure - PdetMax) in 896 datasets. Multivariate analysis was used to analyse the data further by age group and diagnosis - urodynamic stress incontinence (USI); detrusor overactivity (DO); mixed USI and DO; no urodynamic abnormality. Results showed that diagnosis accounts for a significant amount of variation in all four of the dependent variables Age group shows a significant effect on voiding volume but does not show significant effects on any other variable studied. There is no significant interaction term in any of the analyses, meaning that age and diagnosis do not appear to function together, e.g. age does not relate to flow rate centile, maximum flow rate or PdetQMax. It was concluded that the data suggest that there is no significant change in voiding function related to age. In the elderly, the main alteration in voiding is due to a higher prevalence of DO. PMID:24219733
[Influence of the season of birth of male rats on some parameters of biological age].
Matveeva, Iu P; Lotosh, T A; Iunash, V D; Vinogradova, I A
2013-11-01
The influence of the duration of daylight in the condition of natural lightning in the North-West part of Russia on the dynamics of parameters of biological age in male rats according to the season of birth had been studied during two years. It was found out that alteration of the duration of daylight regardless of the male rats season of birth modified rate of sexual maturation, growth, weight, food and water consumption, daily urine output and blood glucose compared with the analogous parameters in the condition of standard light and dark interchange.
[Influence of the season of birth of male rats on some parameters of biological age].
2013-11-01
The influence of the duration of daylight in the condition of natural lightning in the North-West part of Russia on the dynamics of parameters of biological age in male rats according to the season of birth had been studied during two years. It was found out that alteration of the duration of daylight regardless of the male rats season of birth modified rate of sexual maturation, growth, weight, food and water consumption, daily urine output and blood glucose compared with the analogous parameters in the condition of standard light and dark interchange. PMID:25507636
[Influence of the season of birth of male rats on some parameters of biological age].
Matveeva, Iu P; Lotosh, T A; Iunash, V D; Vinogradova, I A
2013-11-01
The influence of the duration of daylight in the condition of natural lightning in the North-West part of Russia on the dynamics of parameters of biological age in male rats according to the season of birth had been studied during two years. It was found out that alteration of the duration of daylight regardless of the male rats season of birth modified rate of sexual maturation, growth, weight, food and water consumption, daily urine output and blood glucose compared with the analogous parameters in the condition of standard light and dark interchange. PMID:25427386
Molecular size and molecular size distribution affecting traditional balsamic vinegar aging.
Falcone, Pasquale Massimiliano; Giudici, Paolo
2008-08-27
A first attempt at a semiquantitative study of molecular weight (MW) and molecular weight distribution (MWD) in cooked grape must and traditional balsamic vinegar (TBV) with increasing well-defined age was performed by high-performance liquid size exclusion chromatography (SEC) using dual detection, that is, differential refractive index (DRI) and absorbance (UV-vis) based detectors. With this aim, MW and MWD, including number- and weight-average MW and polydispersity, were determined with respect to a secondary standard and then analyzed. All investigated vinegar samples were recognized as compositionally and structurally heterogeneous blends of copolymers (melanoidins) spreading over a wide range of molecular sizes: the relative MW ranged from 2 to >2000 kDa. The extent of the polymerization reactions was in agreement with the TBV browning kinetics. MWD parameters varied asymptotically toward either upper or lower limits during aging, reflecting a nonequilibrium status of the balance between polymerization and depolymerization reactions in TBV. MWD parameters were proposed as potential aging markers of TBV. PMID:18656930
Evolutionary theory of ageing and the problem of correlated Gompertz parameters.
Burger, Oskar; Missov, Trifon I
2016-11-01
The Gompertz mortality model is often used to evaluate evolutionary theories of ageing, such as the Medawar-Williams' hypothesis that high extrinsic mortality leads to faster ageing. However, fits of the Gompertz mortality model to data often find the opposite result that mortality is negatively correlated with the rate of ageing. This negative correlation has been independently discovered in several taxa and is known in actuarial studies of ageing as the Strehler-Mildvan correlation. We examine the role of mortality selection in determining late-life variation in susceptibility to death, which has been suggested to be the cause of this negative correlation. We demonstrate that fixed-frailty models that account for heterogeneity in frailty do not remove the correlation and that the correlation is an inherent statistical property of the Gompertz distribution. Linking actuarial and biological rates of ageing will continue to be a pressing challenge, but the Strehler-Mildvan correlation itself should not be used to diagnose any biological, physiological, or evolutionary process. These findings resolve some key tensions between theory and data that affect evolutionary and biological studies of ageing and mortality. Tests of evolutionary theories of ageing should include direct measures of physiological performance or condition.
The eye lens: age-related trends and individual variations in refractive index and shape parameters
Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto
2015-01-01
The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height. PMID:26416418
The eye lens: age-related trends and individual variations in refractive index and shape parameters.
Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto
2015-10-13
The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height.
The eye lens: age-related trends and individual variations in refractive index and shape parameters.
Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto
2015-10-13
The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height. PMID:26416418
Pye, Stephen R.; Vanderschueren, Dirk; Boonen, Steven; Gielen, Evelien; Adams, Judith E.; Ward, Kate A.; Lee, David M.; Bartfai, György; Casanueva, Felipe F.; Finn, Joseph D.; Forti, Gianni; Giwercman, Aleksander; Han, Thang S.; Huhtaniemi, Ilpo T.; Kula, Krzysztof; Lean, Michael E.; Pendleton, Neil; Punab, Margus; Wu, Frederick C.; O'Neill, Terence W.
2015-01-01
Background: low bone mineral density measured by dual-energy x-ray absorptiometry is associated with increased mortality. The relationship between other skeletal phenotypes and mortality is unclear. The aim of this study was to determine the relationship between quantitative heel ultrasound parameters and mortality in a cohort of European men. Methods: men aged 40–79 years were recruited for participation in a prospective study of male ageing: the European Male Ageing Study (EMAS). At baseline, subjects attended for quantitative ultrasound (QUS) of the heel (Hologic—SAHARA) and completed questionnaires on lifestyle factors and co-morbidities. Height and weight were measured. After a median of 4.3 years, subjects were invited to attend a follow-up assessment, and reasons for non-participation, including death, were recorded. The relationship between QUS parameters (broadband ultrasound attenuation [BUA] and speed of sound [SOS]) and mortality was assessed using Cox proportional hazards model. Results: from a total of 3,244 men (mean age 59.8, standard deviation [SD] 10.8 years), 185 (5.7%) died during the follow-up period. After adjusting for age, centre, body mass index, physical activity, current smoking, number of co-morbidities and general health, each SD decrease in BUA was associated with a 20% higher risk of mortality (hazard ratio [HR] per SD = 1.2; 95% confidence interval [CI] = 1.0–1.4). Compared with those in higher quintiles (2nd–5th), those in the lowest quintile of BUA and SOS had a greater mortality risk (BUA: HR = 1.6; 95% CI = 1.1–2.3 and SOS: HR = 1.6; 95% CI = 1.2–2.2). Conclusion: lower heel ultrasound parameters are associated with increased mortality in European men. PMID:26162912
NASA Astrophysics Data System (ADS)
Pasari, S.; Kundu, D.; Dikshit, O.
2012-12-01
Earthquake recurrence interval is one of the important ingredients towards probabilistic seismic hazard assessment (PSHA) for any location. Exponential, gamma, Weibull and lognormal distributions are quite established probability models in this recurrence interval estimation. However, they have certain shortcomings too. Thus, it is imperative to search for some alternative sophisticated distributions. In this paper, we introduce a three-parameter (location, scale and shape) exponentiated exponential distribution and investigate the scope of this distribution as an alternative of the afore-mentioned distributions in earthquake recurrence studies. This distribution is a particular member of the exponentiated Weibull distribution. Despite of its complicated form, it is widely accepted in medical and biological applications. Furthermore, it shares many physical properties with gamma and Weibull family. Unlike gamma distribution, the hazard function of generalized exponential distribution can be easily computed even if the shape parameter is not an integer. To contemplate the plausibility of this model, a complete and homogeneous earthquake catalogue of 20 events (M ≥ 7.0) spanning for the period 1846 to 1995 from North-East Himalayan region (20-32 deg N and 87-100 deg E) has been used. The model parameters are estimated using maximum likelihood estimator (MLE) and method of moment estimator (MOME). No geological or geophysical evidences have been considered in this calculation. The estimated conditional probability reaches quite high after about a decade for an elapsed time of 17 years (i.e. 2012). Moreover, this study shows that the generalized exponential distribution fits the above data events more closely compared to the conventional models and hence it is tentatively concluded that generalized exponential distribution can be effectively considered in earthquake recurrence studies.
Heidari, M.; Ranjithan, S.R.
1998-01-01
In using non-linear optimization techniques for estimation of parameters in a distributed ground water model, the initial values of the parameters and prior information about them play important roles. In this paper, the genetic algorithm (GA) is combined with the truncated-Newton search technique to estimate groundwater parameters for a confined steady-state ground water model. Use of prior information about the parameters is shown to be important in estimating correct or near-correct values of parameters on a regional scale. The amount of prior information needed for an accurate solution is estimated by evaluation of the sensitivity of the performance function to the parameters. For the example presented here, it is experimentally demonstrated that only one piece of prior information of the least sensitive parameter is sufficient to arrive at the global or near-global optimum solution. For hydraulic head data with measurement errors, the error in the estimation of parameters increases as the standard deviation of the errors increases. Results from our experiments show that, in general, the accuracy of the estimated parameters depends on the level of noise in the hydraulic head data and the initial values used in the truncated-Newton search technique.In using non-linear optimization techniques for estimation of parameters in a distributed ground water model, the initial values of the parameters and prior information about them play important roles. In this paper, the genetic algorithm (GA) is combined with the truncated-Newton search technique to estimate groundwater parameters for a confined steady-state ground water model. Use of prior information about the parameters is shown to be important in estimating correct or near-correct values of parameters on a regional scale. The amount of prior information needed for an accurate solution is estimated by evaluation of the sensitivity of the performance function to the parameters. For the example presented here, it is
Parameter estimation in nonlinear distributed systems - Approximation theory and convergence results
NASA Technical Reports Server (NTRS)
Banks, H. T.; Reich, Simeon; Rosen, I. G.
1988-01-01
An abstract approximation framework and convergence theory is described for Galerkin approximations applied to inverse problems involving nonlinear distributed parameter systems. Parameter estimation problems are considered and formulated as the minimization of a least-squares-like performance index over a compact admissible parameter set subject to state constraints given by an inhomogeneous nonlinear distributed system. The theory applies to systems whose dynamics can be described by either time-independent or nonstationary strongly maximal monotonic operators defined on a reflexive Banach space which is densely and continuously embedded in a Hilbert space. It is demonstrated that if readily verifiable conditions on the system's dependence on the unknown parameters are satisfied, and the usual Galerkin approximation assumption holds, then solutions to the approximating problems exist and approximate a solution to the original infinite-dimensional identification problem.
NASA Astrophysics Data System (ADS)
Ligi, R.; Creevey, O.; Mourard, D.; Crida, A.; Lagrange, A.-M.; Nardetto, N.; Perraut, K.; Schultheis, M.; Tallon-Bosc, I.; ten Brummelaar, T.
2016-02-01
Context. Accurate stellar parameters are needed in numerous domains of astrophysics. The position of stars on the Hertzsprung-Russell diagram is an important indication of their structure and evolution, and it helps improve stellar models. Furthermore, the age and mass of stars hosting planets are required elements for studying exoplanetary systems. Aims: We aim at determining accurate parameters of a set of 18 bright exoplanet host and potential host stars from interferometric measurements, photometry, and stellar models. Methods: Using the VEGA/CHARA interferometer operating in the visible domain, we measured the angular diameters of 18 stars, ten of which host exoplanets. We combined them with their distances to estimate their radii. We used photometry to derive their bolometric flux and, then, their effective temperature and luminosity to place them on the H-R diagram. We then used the PARSEC models to derive their best fit ages and masses, with error bars derived from Monte Carlo calculations. Results: Our interferometric measurements lead to an average of 1.9% uncertainty on angular diameters and 3% on stellar radii. There is good agreement between measured and indirect estimations of angular diameters (either from SED fitting or from surface brightness relations) for main sequence (MS) stars, but not as good for more evolved stars. For each star, we provide a likelihood map in the mass-age plane; typically, two distinct sets of solutions appear (an old and a young age). The errors on the ages and masses that we provide account for the metallicity uncertainties, which are often neglected by other works. From measurements of its radius and density, we also provide the mass of 55 Cnc independently of models. From the stellar masses, we provide new estimates of semi-major axes and minimum masses of exoplanets with reliable uncertainties. We also derive the radius, density, and mass of 55 Cnc e, a super-Earth that transits its stellar host. Our exoplanetary
NASA Technical Reports Server (NTRS)
Kemmerer, A. J.; Benigno, J. A.
1973-01-01
The author has identified the following significant results. A feasibility study to demonstrate the potential of satellites for providing fisheries significant information was conducted in the Mississippi Sound and adjacent offshore waters. Attempts were made to relate satellite acquired imagery to selected oceanographic parameters and then to relate these parameters to aircraft remotely sensed distribution patterns of resident surface schooling fishes. Initial results suggest that this approach is valid and that the satellite acquired imagery may have important fisheries resource assessment implications.
NASA Technical Reports Server (NTRS)
Kemmerer, A. J.; Benigno, J. A.
1973-01-01
A feasibility study to demonstrate the potential of satellites for providing fisheries significant information was conducted in the Mississippi Sound and adjacent offshore waters. Attempts were made to relate satellite acquired imagery to selected oceanographic parameters and then to relate these parameters to aircraft remotely sensed distribution patterns of resident surface schooling fishes. Initial results suggest that this approach is valid and that the satellite acquired imagery may have important fisheries resource assessment implications.
Determination of the statistical distributions of model parameters for probabilistic risk assessment
Fields, D.E.; Glandon, S.R.
1981-01-01
Successful probabilistic risk assessment depends heavily on knowledge of the distribution of model parameters we have developed. The TERPED computer code is a versatile methodology for determining with what confidence a parameter set may be considered to have a normal or lognormal frequency distribution. Several measures of central tendency are computed. Other options include computation of the chi-square statistic, the Kolmogorov-Smirnov non-parametric statistic, and Pearson's correlation coefficient. Cumulative probability plots are produced either in high resolution (pen-and-ink or film) or in printerplot form.
Comparison of Two New Robust Parameter Estimation Methods for the Power Function Distribution.
Shakeel, Muhammad; Haq, Muhammad Ahsan Ul; Hussain, Ijaz; Abdulhamid, Alaa Mohamd; Faisal, Muhammad
2016-01-01
Estimation of any probability distribution parameters is vital because imprecise and biased estimates can be misleading. In this study, we investigate a flexible power function distribution and introduced new two methods such as, probability weighted moments, and generalized probability weighted methods for its parameters. We compare their results with L-moments, trimmed L-moments by a simulation study and a real data example based on performance measures such as, mean square error and total deviation. We concluded that all the methods perform well in the case of large sample size (n>30), however, the generalized probability weighted moment method performs better for small sample size. PMID:27500404
Factorization and reduction methods for optimal control of distributed parameter systems
NASA Technical Reports Server (NTRS)
Burns, J. A.; Powers, R. K.
1985-01-01
A Chandrasekhar-type factorization method is applied to the linear-quadratic optimal control problem for distributed parameter systems. An aeroelastic control problem is used as a model example to demonstrate that if computationally efficient algorithms, such as those of Chandrasekhar-type, are combined with the special structure often available to a particular problem, then an abstract approximation theory developed for distributed parameter control theory becomes a viable method of solution. A numerical scheme based on averaging approximations is applied to hereditary control problems. Numerical examples are given.
Comparison of Two New Robust Parameter Estimation Methods for the Power Function Distribution
Shakeel, Muhammad; Haq, Muhammad Ahsan ul; Abdulhamid, Alaa Mohamd; Faisal, Muhammad
2016-01-01
Estimation of any probability distribution parameters is vital because imprecise and biased estimates can be misleading. In this study, we investigate a flexible power function distribution and introduced new two methods such as, probability weighted moments, and generalized probability weighted methods for its parameters. We compare their results with L-moments, trimmed L-moments by a simulation study and a real data example based on performance measures such as, mean square error and total deviation. We concluded that all the methods perform well in the case of large sample size (n>30), however, the generalized probability weighted moment method performs better for small sample size. PMID:27500404
Parameter estimation for the Pearson type 3 distribution using order statistics
NASA Astrophysics Data System (ADS)
Rocky Durrans, S.
1992-05-01
The Pearson type 3 distribution and its relatives, the log Pearson type 3 and gamma family of distributions, are among the most widely applied in the field of hydrology. Parameter estimation for these distributions has been accomplished using the method of moments, the methods of mixed moments and generalized moments, and the methods of maximum likelihood and maximum entropy. This study evaluates yet another estimation approach, which is based on the use of the properties of an extreme-order statistic. Based on the hypothesis that the population is distributed as Pearson type 3, this estimation approach yields both parameter and 100-year quantile estimators that have lower biases and variances than those of the method of moments approach as recommended by the US Water Resources Council.
Mean age distribution of inorganic soil-nitrogen
NASA Astrophysics Data System (ADS)
Woo, Dong K.; Kumar, Praveen
2016-07-01
Excess reactive nitrogen in soils of intensively managed landscapes causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a model to characterize the "age" of inorganic soil-nitrogen (nitrate, and ammonia/ammonium). We use the general theory of age, which provides an assessment of the time elapsed since inorganic nitrogen has been introduced into the soil system. We analyze a corn-corn-soybean rotation, common in the Midwest United States, as an example application. We observe two counter-intuitive results: (1) the mean nitrogen age in the topsoil layer is relatively high; and (2) mean nitrogen age is lower under soybean cultivation compared to corn although no fertilizer is applied for soybean cultivation. The first result can be explained by cation-exchange of ammonium that retards the leaching of nitrogen, resulting in an increase in the mean nitrogen age near the soil surface. The second result arises because the soybean utilizes the nitrogen fertilizer left from the previous year, thereby removing the older nitrogen and reducing mean nitrogen age. Estimating the mean nitrogen age can thus serve as an important tool to disentangle complex nitrogen dynamics by providing a nuanced characterization of the time scales of soil-nitrogen transformation and transport processes.
A unified framework for approximation in inverse problems for distributed parameter systems
NASA Technical Reports Server (NTRS)
Banks, H. T.; Ito, K.
1988-01-01
A theoretical framework is presented that can be used to treat approximation techniques for very general classes of parameter estimation problems involving distributed systems that are either first or second order in time. Using the approach developed, one can obtain both convergence and stability (continuous dependence of parameter estimates with respect to the observations) under very weak regularity and compactness assumptions on the set of admissible parameters. This unified theory can be used for many problems found in the recent literature and in many cases offers significant improvements to existing results.
Quantification of Parameter Uncertainty of a Distributed Hydraulic Model Using Ensemble Smoother
NASA Astrophysics Data System (ADS)
Li, Ning; McLaughlin, Dennis; Kinzelbach, Wolfgang; Li, Wenpeng; Dong, Xinguang
2014-05-01
Yanqi basin is an important agricultural region in Xinjiang, in Northwest China. The irrigated agricultural land has been increasing in the past decades and made the basin suffer from many environmental problems such as soil salinization, decreased lake level, deteriorated lake water quality, decreased surface water flow to the downstream and damaged riverine forests. A 3-dimensional distributed numerical flow and transport model is built using MIKESHE/MIKE11 which contains saturated and unsaturated zones, rivers and lakes. It allows to better understand the impacts of individual hydrological units and their interactions. Before using the model for quantifying solutions for the environmental problems, the parameter uncertainties of the complex distributed model are assessed using an Ensemble Smoother (ES). ES is a data assimilation method to improve an ensemble of prior parameters by assimilating time series of observations over the whole time period available. It is basically a stochastic calibration method. In this case study, an iterative ES is applied, called Ensemble Smoother with Multiple Data Assimilation (ESMDA) (Emerick and Reynolds, 2012). Two alternatives are considered to update parameters in each iteration. One is the Ensemble Kalman Filter with perturbed observations and the other is an Unbiased Square root filter which updates parameter means and perturbations separately. Seventeen parameters are chosen from the distributed flow and transport model to quantify their uncertainty. Fifty prior replicates of each parameter are generated using the Latin Hypercube Sampling method. The distribution of posterior parameters and outputs obtained from the alternative methods are similar. The results indicate that the uncertainty of the parameters is narrowed during the smoother updating process, reflecting the information obtained from the observations. The most sensitive parameters are the dispersion coefficient of the lakes and the hydraulic conductivity of
SU-E-T-113: Dose Distribution Using Respiratory Signals and Machine Parameters During Treatment
Imae, T; Haga, A; Saotome, N; Kida, S; Nakano, M; Takeuchi, Y; Shiraki, T; Yano, K; Yamashita, H; Nakagawa, K; Ohtomo, K
2014-06-01
Purpose: Volumetric modulated arc therapy (VMAT) is a rotational intensity-modulated radiotherapy (IMRT) technique capable of acquiring projection images during treatment. Treatment plans for lung tumors using stereotactic body radiotherapy (SBRT) are calculated with planning computed tomography (CT) images only exhale phase. Purpose of this study is to evaluate dose distribution by reconstructing from only the data such as respiratory signals and machine parameters acquired during treatment. Methods: Phantom and three patients with lung tumor underwent CT scans for treatment planning. They were treated by VMAT while acquiring projection images to derive their respiratory signals and machine parameters including positions of multi leaf collimators, dose rates and integrated monitor units. The respiratory signals were divided into 4 and 10 phases and machine parameters were correlated with the divided respiratory signals based on the gantry angle. Dose distributions of each respiratory phase were calculated from plans which were reconstructed from the respiratory signals and the machine parameters during treatment. The doses at isocenter, maximum point and the centroid of target were evaluated. Results and Discussion: Dose distributions during treatment were calculated using the machine parameters and the respiratory signals detected from projection images. Maximum dose difference between plan and in treatment distribution was −1.8±0.4% at centroid of target and dose differences of evaluated points between 4 and 10 phases were no significant. Conclusion: The present method successfully evaluated dose distribution using respiratory signals and machine parameters during treatment. This method is feasible to verify the actual dose for moving target.
NASA Astrophysics Data System (ADS)
Chen, Y.; Li, J.; Xu, H.
2016-01-01
Physically based distributed hydrological models (hereafter referred to as PBDHMs) divide the terrain of the whole catchment into a number of grid cells at fine resolution and assimilate different terrain data and precipitation to different cells. They are regarded to have the potential to improve the catchment hydrological process simulation and prediction capability. In the early stage, physically based distributed hydrological models are assumed to derive model parameters from the terrain properties directly, so there is no need to calibrate model parameters. However, unfortunately the uncertainties associated with this model derivation are very high, which impacted their application in flood forecasting, so parameter optimization may also be necessary. There are two main purposes for this study: the first is to propose a parameter optimization method for physically based distributed hydrological models in catchment flood forecasting by using particle swarm optimization (PSO) algorithm and to test its competence and to improve its performances; the second is to explore the possibility of improving physically based distributed hydrological model capability in catchment flood forecasting by parameter optimization. In this paper, based on the scalar concept, a general framework for parameter optimization of the PBDHMs for catchment flood forecasting is first proposed that could be used for all PBDHMs. Then, with the Liuxihe model as the study model, which is a physically based distributed hydrological model proposed for catchment flood forecasting, the improved PSO algorithm is developed for the parameter optimization of the Liuxihe model in catchment flood forecasting. The improvements include adoption of the linearly decreasing inertia weight strategy to change the inertia weight and the arccosine function strategy to adjust the acceleration coefficients. This method has been tested in two catchments in southern China with different sizes, and the results show
Helsel, D.R.; Gilliom, R.J.
1986-01-01
Estimates of distributional parameters (mean, standard deviation, median, interquartile range) are often desired for data sets containing censored observations. Eight methods for estimating these parameters have been evaluated by R. J. Gilliom and D. R. Helsel (this issue) using Monte Carlo simulations. To verify those findings, the same methods are now applied to actual water quality data. The best method (lowest root-mean-squared error (rmse)) over all parameters, sample sizes, and censoring levels is log probability regression (LR), the method found best in the Monte Carlo simulations. Best methods for estimating moment or percentile parameters separately are also identical to the simulations. Reliability of these estimates can be expressed as confidence intervals using rmse and bias values taken from the simulation results. Finally, a new simulation study shows that best methods for estimating uncensored sample statistics from censored data sets are identical to those for estimating population parameters.
NASA Astrophysics Data System (ADS)
Dai, Mi; Wang, Yun
2016-06-01
In order to obtain robust cosmological constraints from Type Ia supernova (SN Ia) data, we have applied Markov Chain Monte Carlo (MCMC) to SN Ia lightcurve fitting. We develop a method for sampling the resultant probability density distributions (pdf) of the SN Ia lightcuve parameters in the MCMC likelihood analysis to constrain cosmological parameters, and validate it using simulated data sets. Applying this method to the `joint lightcurve analysis (JLA)' data set of SNe Ia, we find that sampling the SN Ia lightcurve parameter pdf's leads to cosmological parameters closer to that of a flat Universe with a cosmological constant, compared to the usual practice of using only the best-fitting values of the SN Ia lightcurve parameters. Our method will be useful in the use of SN Ia data for precision cosmology.
Thompson, Robert S.; Anderson, Katherine H.; Bartlein, Patrick J.
1999-01-01
This atlas explores the continental-scale relations between the geographic ranges of woody plant species and climate in North America. A 25-km equal-area grid of modern climatic and bioclimatic parameters was constructed from instrumental weather records. The geographic distributions of selected tree and shrub species were digitized, and the presence or absence of each species was determined for each cell on the 25-km grid, thus providing a basis for comparing climatic data and species distributions. The relations between climate and plant distributions are explored in graphical and tabular form. The results of this effort are primarily intended for use in biogeographic, paleoclimatic, and global-change research.
The reduced order model problem in distributed parameter systems adaptive identification and control
NASA Technical Reports Server (NTRS)
Johnson, C. R., Jr.
1980-01-01
The research concerning the reduced order model problem in distributed parameter systems is reported. The adaptive control strategy was chosen for investigation in the annular momentum control device. It is noted, that if there is no observation spill over, and no model errors, an indirect adaptive control strategy can be globally stable. Recent publications concerning adaptive control are included.
The values of the parameters of some multilayer distributed RC null networks
NASA Technical Reports Server (NTRS)
Huelsman, L. P.; Raghunath, S.
1974-01-01
In this correspondence, the values of the parameters of some multilayer distributed RC notch networks are determined, and the usually accepted values are shown to be in error. The magnitude of the error is illustrated by graphs of the frequency response of the networks.
In this article, we consider the least-squares approach for estimating parameters of a spatial variogram and establish consistency and asymptotic normality of these estimators under general conditions. Large-sample distributions are also established under a sp...
Methods for the identification of material parameters in distributed models for flexible structures
NASA Technical Reports Server (NTRS)
Banks, H. T.; Crowley, J. M.; Rosen, I. G.
1986-01-01
Theoretical and numerical results are presented for inverse problems involving estimation of spatially varying parameters such as stiffness and damping in distributed models for elastic structures such as Euler-Bernoulli beams. An outline of algorithms used and a summary of computational experiences are presented.
An EOQ Model with Two-Parameter Weibull Distribution Deterioration and Price-Dependent Demand
ERIC Educational Resources Information Center
Mukhopadhyay, Sushanta; Mukherjee, R. N.; Chaudhuri, K. S.
2005-01-01
An inventory replenishment policy is developed for a deteriorating item and price-dependent demand. The rate of deterioration is taken to be time-proportional and the time to deterioration is assumed to follow a two-parameter Weibull distribution. A power law form of the price dependence of demand is considered. The model is solved analytically…
Strategic Decision-Making Learning from Label Distributions: An Approach for Facial Age Estimation
Zhao, Wei; Wang, Han
2016-01-01
Nowadays, label distribution learning is among the state-of-the-art methodologies in facial age estimation. It takes the age of each facial image instance as a label distribution with a series of age labels rather than the single chronological age label that is commonly used. However, this methodology is deficient in its simple decision-making criterion: the final predicted age is only selected at the one with maximum description degree. In many cases, different age labels may have very similar description degrees. Consequently, blindly deciding the estimated age by virtue of the highest description degree would miss or neglect other valuable age labels that may contribute a lot to the final predicted age. In this paper, we propose a strategic decision-making label distribution learning algorithm (SDM-LDL) with a series of strategies specialized for different types of age label distribution. Experimental results from the most popular aging face database, FG-NET, show the superiority and validity of all the proposed strategic decision-making learning algorithms over the existing label distribution learning and other single-label learning algorithms for facial age estimation. The inner properties of SDM-LDL are further explored with more advantages. PMID:27367691
Gilliom, R.J.; Helsel, D.R.
1986-01-01
A recurring difficulty encountered in investigations of many metals and organic contaminants in ambient waters is that a substantial portion of water sample concentrations are below limits of detection established by analytical laboratories. Several methods were evaluated for estimating distributional parameters for such censored data sets using only uncensored observations. Their reliabilities were evaluated by a Monte Carlo experiment in which small samples were generated from a wide range of parent distributions and censored at varying levels. Eight methods were used to estimate the mean, standard deviation, median, and interquartile range. Criteria were developed, based on the distribution of uncensored observations, for determining the best performing parameter estimation method for any particular data set. The most robust method for minimizing error in censored-sample estimates of the four distributional parameters over all simulation conditions was the log-probability regression method. With this method, censored observations are assumed to follow the zero-to-censoring level portion of a lognormal distribution obtained by a least squares regression between logarithms of uncensored concentration observations and their z scores.
Effects of Exendin-4 on Male Reproductive Parameters of D-Galactose Induced Aging Mouse Model
Ahangarpour, Akram; Heidari, Hamid
2014-01-01
Purpose The purpose of this study was to evaluate the role of exendin-4 on reproductive alteration in a D-galactose-induced aging mouse model. Materials and Methods In this experimental study, 72 male Naval Medical Research Institute mice (20~25 g) were randomly divided into six groups: control, exendin-4 (1 nmol/kg), exendin-4 (10 nmol/kg), D-galactose (500 mg/kg), D-galactose+exendin-4 (1 nmol/kg), and D-galactose+exendin-4 (10 nmol/kg). The aging model animals were gavaged with D-galactose for six weeks, and exendin-4 was injected intraperitoneally in the last 10 days. At the end of treatment serum luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels were evaluated and the cauda epididymis and testis were removed to analyze the sperm count and testis morphology. Results The testis weight and volume decreased in the D-galactose group (p<0.01 and p<0.05) respectively. Exendin-4 (1, 10 nmol/kg) increased these parameters in the normal and aging mouse models. Serum LH and FSH levels increased and the sperm count decreased in the D-galactose group (p<0.05). Further, exendin-4 (1 nmol/kg) decreased LH and FSH levels and increased the serum testosterone level and sperm count in both normal and aging animals. Conclusions D-galactose can induce aging alternations in the male reproductive system such as decreased sperm count and increased serum LH and FSH levels through reactive oxygen species over production and reduced antioxidant enzyme activity. Further, co-administration of exendin-4 reduced reproductive complications of D-galactose in an aging mouse model. PMID:25606567
Evaluation of Experimental Parameters in the Accelerated Aging of Closed-Cell Foam Insulation
Stovall, Therese K; Vanderlan, Michael; Atchley, Jerald Allen
2012-12-01
The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C1303 standard test method led to the ruggedness test described here. This test program included the aging of full size insulation specimens for time periods of five years for direct comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. The test protocol has been completed and this report provides a detailed evaluation of the impact of the test parameters on the accuracy of the 5-year thermal conductivity prediction.
Massoudieh, Arash; Visser, Ate; Sharifi, Soroosh; Broers, Hans Peter
2013-10-15
The mixing of groundwaters with different ages in aquifers, groundwater age is more appropriately represented by a distribution rather than a scalar number. To infer a groundwater age distribution from environmental tracers, a mathematical form is often assumed for the shape of the distribution and the parameters of the mathematical distribution are estimated using deterministic or stochastic inverse methods. We found that the prescription of the mathematical form limits the exploration of the age distribution to the shapes that can be described by the selected distribution. In this paper, the use of freeform histograms as groundwater age distributions is evaluated.more » A Bayesian Markov Chain Monte Carlo approach is used to estimate the fraction of groundwater in each histogram bin. This method was able to capture the shape of a hypothetical gamma distribution from the concentrations of four age tracers. The number of bins that can be considered in this approach is limited based on the number of tracers available. The histogram method was also tested on tracer data sets from Holten (The Netherlands; 3H, 3He, 85Kr, 39Ar) and the La Selva Biological Station (Costa-Rica; SF 6, CFCs, 3H, 4He and 14C), and compared to a number of mathematical forms. According to standard Bayesian measures of model goodness, the best mathematical distribution performs better than the histogram distributions in terms of the ability to capture the observed tracer data relative to their complexity. Among the histogram distributions, the four bin histogram performs better in most of the cases. The Monte Carlo simulations showed strong correlations in the posterior estimates of bin contributions, indicating that these bins cannot be well constrained using the available age tracers. The fact that mathematical forms overall perform better than the freeform histogram does not undermine the benefit of the freeform approach, especially for the cases where a larger amount of observed data is
Massoudieh, Arash; Visser, Ate; Sharifi, Soroosh; Broers, Hans Peter
2013-10-15
The mixing of groundwaters with different ages in aquifers, groundwater age is more appropriately represented by a distribution rather than a scalar number. To infer a groundwater age distribution from environmental tracers, a mathematical form is often assumed for the shape of the distribution and the parameters of the mathematical distribution are estimated using deterministic or stochastic inverse methods. We found that the prescription of the mathematical form limits the exploration of the age distribution to the shapes that can be described by the selected distribution. In this paper, the use of freeform histograms as groundwater age distributions is evaluated. A Bayesian Markov Chain Monte Carlo approach is used to estimate the fraction of groundwater in each histogram bin. This method was able to capture the shape of a hypothetical gamma distribution from the concentrations of four age tracers. The number of bins that can be considered in this approach is limited based on the number of tracers available. The histogram method was also tested on tracer data sets from Holten (The Netherlands; ^{3}H, ^{3}He, ^{85}Kr, ^{39}Ar) and the La Selva Biological Station (Costa-Rica; SF_{ 6}, CFCs, ^{3}H, ^{4}He and ^{14}C), and compared to a number of mathematical forms. According to standard Bayesian measures of model goodness, the best mathematical distribution performs better than the histogram distributions in terms of the ability to capture the observed tracer data relative to their complexity. Among the histogram distributions, the four bin histogram performs better in most of the cases. The Monte Carlo simulations showed strong correlations in the posterior estimates of bin contributions, indicating that these bins cannot be well constrained using the available age tracers. The fact that mathematical forms overall perform better than the freeform histogram does not undermine the benefit of the
Variation of Biophysical Parameters of the Skin with Age, Gender, and Body Region
Firooz, Alireza; Sadr, Bardia; Babakoohi, Shahab; Sarraf-Yazdy, Maryam; Fanian, Ferial; Kazerouni-Timsar, Ali; Nassiri-Kashani, Mansour; Naghizadeh, Mohammad Mehdi; Dowlati, Yahya
2012-01-01
Background. Understanding the physiological, chemical, and biophysical characteristics of the skin helps us to arrange a proper approach to the management of skin diseases. Objective. The aim of this study was to measure 6 biophysical characteristics of normal skin (sebum content, hydration, transepidermal water loss (TEWL), erythema index, melanin index, and elasticity) in a normal population and assess the effect of sex, age, and body location on them. Methods. Fifty healthy volunteers in 5 age groups (5 males and females in each) were enrolled in this study. A multifunctional skin physiology monitor (Courage & Khazaka electronic GmbH, Germany) was used to measure skin sebum content, hydration, TEWL, erythema index, melanin index, and elasticity in 8 different locations of the body. Results. There were significant differences between the hydration, melanin index, and elasticity of different age groups. Regarding the locations, forehead had the highest melanin index, where as palm had the lowest value. The mean values of erythema index and melanin index and TEWL were significantly higher in males and anatomic location was a significant independent factor for all of 6 measured parameters. Conclusion. Several biophysical properties of the skin vary among different gender, age groups, and body locations. PMID:22536139
Prediction of Parameters Distribution of Upward Boiling Two-Phase Flow With Two-Fluid Models
Yao, Wei; Morel, Christophe
2002-07-01
In this paper, a multidimensional two-fluid model with additional turbulence k - {epsilon} equations is used to predict the two-phase parameters distribution in freon R12 boiling flow. The 3D module of the CATHARE code is used for numerical calculation. The DEBORA experiment has been chosen to evaluate our models. The radial profiles of the outlet parameters were measured by means of an optical probe. The comparison of the radial profiles of void fraction, liquid temperature, gas velocity and volumetric interfacial area at the end of the heated section shows that the multidimensional two-fluid model with proper constitutive relations can yield reasonably predicted results in boiling conditions. Sensitivity tests show that the turbulent dispersion force, which involves the void fraction gradient, plays an important role in determining the void fraction distribution; and the turbulence eddy viscosity is a significant factor to influence the liquid temperature distribution. (authors)
Comparison of Two Methods Used to Model Shape Parameters of Pareto Distributions
Liu, C.; Charpentier, R.R.; Su, J.
2011-01-01
Two methods are compared for estimating the shape parameters of Pareto field-size (or pool-size) distributions for petroleum resource assessment. Both methods assume mature exploration in which most of the larger fields have been discovered. Both methods use the sizes of larger discovered fields to estimate the numbers and sizes of smaller fields: (1) the tail-truncated method uses a plot of field size versus size rank, and (2) the log-geometric method uses data binned in field-size classes and the ratios of adjacent bin counts. Simulation experiments were conducted using discovered oil and gas pool-size distributions from four petroleum systems in Alberta, Canada and using Pareto distributions generated by Monte Carlo simulation. The estimates of the shape parameters of the Pareto distributions, calculated by both the tail-truncated and log-geometric methods, generally stabilize where discovered pool numbers are greater than 100. However, with fewer than 100 discoveries, these estimates can vary greatly with each new discovery. The estimated shape parameters of the tail-truncated method are more stable and larger than those of the log-geometric method where the number of discovered pools is more than 100. Both methods, however, tend to underestimate the shape parameter. Monte Carlo simulation was also used to create sequences of discovered pool sizes by sampling from a Pareto distribution with a discovery process model using a defined exploration efficiency (in order to show how biased the sampling was in favor of larger fields being discovered first). A higher (more biased) exploration efficiency gives better estimates of the Pareto shape parameters. ?? 2011 International Association for Mathematical Geosciences.
Pobrotyn, Piotr; Susło, Robert; Milczanowski, Piotr; Drobnik, Jarosław
2016-01-01
Introduction Rheumatic diseases are becoming more and more common in Poland with the ageing of the population. Nearly 18% of the total hospital admissions in Poland result from rheumatic diseases, which was equivalent to 350 thousand cases in the year 2008. These diseases tend to last for many decades, decreasing both the quality of life and income of the patients as well as increasing the medical institutions’ workload and society's financial burden. The aim of the study was to determine whether the medical care parameters in a rheumatic disease hospital ward show any significant differences among different patient age groups – especially such that would support taking them into account as a basis for adjusting the financial coverage level of medical services. Material and methods Data on hospitalizations at the Rheumatic Diseases Ward of Wroclaw University Hospital in Wroclaw in the years 2009–2015 were analyzed, taking into account the age groups, number of hospital admissions, their duration and causes. Relevant statistical data analysis was performed. Discussion The study revealed that the number of old patients hospitalized at the rheumatic diseases ward increased over the last 6 years and that such statistically significant differences do exist: on average the old patients not only tend to stay much longer at the hospital, but also suffer from a different and more diverse spectrum of diseases in comparison to their younger counterparts. Conclusions The detected differences in medical care parameters support the need for more individualized medical care and increased cost of the hospital stay in the case of older patients. Consequently, those factors justify the necessity to increase the value of medical services in the case of old patients, possibly also taking into account the variation between age subgroups. PMID:27407280
Dana L. Kelly; Albert Malkhasyan
2010-06-01
There is a nearly ubiquitous assumption in PSA that parameter values are at least piecewise-constant in time. As a result, Bayesian inference tends to incorporate many years of plant operation, over which there have been significant changes in plant operational and maintenance practices, plant management, etc. These changes can cause significant changes in parameter values over time; however, failure to perform Bayesian inference in the proper time-dependent framework can mask these changes. Failure to question the assumption of constant parameter values, and failure to perform Bayesian inference in the proper time-dependent framework were noted as important issues in NUREG/CR-6813, performed for the U. S. Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards in 2003. That report noted that “industry lacks tools to perform time-trend analysis with Bayesian updating.” This paper describes an application of time-dependent Bayesian inference methods developed for the European Commission Ageing PSA Network. These methods utilize open-source software, implementing Markov chain Monte Carlo sampling. The paper also illustrates the development of a generic prior distribution, which incorporates multiple sources of generic data via weighting factors that address differences in key influences, such as vendor, component boundaries, conditions of the operating environment, etc.
A "total parameter estimation" method in the varification of distributed hydrological models
NASA Astrophysics Data System (ADS)
Wang, M.; Qin, D.; Wang, H.
2011-12-01
Conventionally hydrological models are used for runoff or flood forecasting, hence the determination of model parameters are common estimated based on discharge measurements at the catchment outlets. With the advancement in hydrological sciences and computer technology, distributed hydrological models based on the physical mechanism such as SWAT, MIKESHE, and WEP, have gradually become the mainstream models in hydrology sciences. However, the assessments of distributed hydrological models and model parameter determination still rely on runoff and occasionally, groundwater level measurements. It is essential in many countries, including China, to understand the local and regional water cycle: not only do we need to simulate the runoff generation process and for flood forecasting in wet areas, we also need to grasp the water cycle pathways and consumption process of transformation in arid and semi-arid regions for the conservation and integrated water resources management. As distributed hydrological model can simulate physical processes within a catchment, we can get a more realistic representation of the actual water cycle within the simulation model. Runoff is the combined result of various hydrological processes, using runoff for parameter estimation alone is inherits problematic and difficult to assess the accuracy. In particular, in the arid areas, such as the Haihe River Basin in China, runoff accounted for only 17% of the rainfall, and very concentrated during the rainy season from June to August each year. During other months, many of the perennial rivers within the river basin dry up. Thus using single runoff simulation does not fully utilize the distributed hydrological model in arid and semi-arid regions. This paper proposed a "total parameter estimation" method to verify the distributed hydrological models within various water cycle processes, including runoff, evapotranspiration, groundwater, and soil water; and apply it to the Haihe river basin in
Clusters and cycles in the cosmic ray age distributions of meteorites
NASA Technical Reports Server (NTRS)
Woodard, M. F.; Marti, K.
1985-01-01
Statistically significant clusters in the cosmic ray exposure age distributions of some groups of iron and stone meteorites were observed, suggesting epochs of enhanced collision and breakups. Fourier analyses of the age distributions of chondrites reveal no significant periods, nor does the same analysis when applied to iron meteorite clusters.
Spatial distribution of the human enamel fracture toughness with aging.
Zheng, Qinghua; Xu, Haiping; Song, Fan; Zhang, Lan; Zhou, Xuedong; Shao, Yingfeng; Huang, Dingming
2013-10-01
A better understanding of the fracture toughness (KIC) of human enamel and the changes induced by aging is important for the clinical treatment of teeth cracks and fractures. We conducted microindentation tests and chemical content measurements on molar teeth from "young" (18 ≤ age ≤ 25) and "old" (55 ≤ age) patients. The KIC and the mineral contents (calcium and phosphorus) in the outer, the middle, and the inner enamel layers within the cuspal and the intercuspal regions of the crown were measured through the Vickers toughness test and Energy Dispersive X-Ray Spectroscopy (EDS), respectively. The elastic modulus used for the KIC calculation was measured through atomic force microscope (AFM)-based nanoindentation tests. In the outer enamel layer, two direction-specific values of the KIC were calculated separately (direction I, crack running parallel to the occlusal surface; direction II, perpendicular to direction I). The mean KIC of the outer enamel layer was lower than that of the internal layers (p<0.05). No other region-related differences in the mechanical properties were found in both groups. In the outer enamel layer, old enamel has a lower KIC, II and higher mineral contents than young enamel (p<0.05). The enamel surface becomes more prone to cracks with aging partly due to the reduction in the interprismatic organic matrix observed with the maturation of enamel.
Budic, Lara; Didenko, Gregor; Dormann, Carsten F
2016-01-01
In species distribution analyses, environmental predictors and distribution data for large spatial extents are often available in long-lat format, such as degree raster grids. Long-lat projections suffer from unequal cell sizes, as a degree of longitude decreases in length from approximately 110 km at the equator to 0 km at the poles. Here we investigate whether long-lat and equal-area projections yield similar model parameter estimates, or result in a consistent bias. We analyzed the environmental effects on the distribution of 12 ungulate species with a northern distribution, as models for these species should display the strongest effect of projectional distortion. Additionally we choose four species with entirely continental distributions to investigate the effect of incomplete cell coverage at the coast. We expected that including model weights proportional to the actual cell area should compensate for the observed bias in model coefficients, and similarly that using land coverage of a cell should decrease bias in species with coastal distribution. As anticipated, model coefficients were different between long-lat and equal-area projections. Having progressively smaller and a higher number of cells with increasing latitude influenced the importance of parameters in models, increased the sample size for the northernmost parts of species ranges, and reduced the subcell variability of those areas. However, this bias could be largely removed by weighting long-lat cells by the area they cover, and marginally by correcting for land coverage. Overall we found little effect of using long-lat rather than equal-area projections in our analysis. The fitted relationship between environmental parameters and occurrence probability differed only very little between the two projection types. We still recommend using equal-area projections to avoid possible bias. More importantly, our results suggest that the cell area and the proportion of a cell covered by land should be
Budic, Lara; Didenko, Gregor; Dormann, Carsten F
2016-01-01
In species distribution analyses, environmental predictors and distribution data for large spatial extents are often available in long-lat format, such as degree raster grids. Long-lat projections suffer from unequal cell sizes, as a degree of longitude decreases in length from approximately 110 km at the equator to 0 km at the poles. Here we investigate whether long-lat and equal-area projections yield similar model parameter estimates, or result in a consistent bias. We analyzed the environmental effects on the distribution of 12 ungulate species with a northern distribution, as models for these species should display the strongest effect of projectional distortion. Additionally we choose four species with entirely continental distributions to investigate the effect of incomplete cell coverage at the coast. We expected that including model weights proportional to the actual cell area should compensate for the observed bias in model coefficients, and similarly that using land coverage of a cell should decrease bias in species with coastal distribution. As anticipated, model coefficients were different between long-lat and equal-area projections. Having progressively smaller and a higher number of cells with increasing latitude influenced the importance of parameters in models, increased the sample size for the northernmost parts of species ranges, and reduced the subcell variability of those areas. However, this bias could be largely removed by weighting long-lat cells by the area they cover, and marginally by correcting for land coverage. Overall we found little effect of using long-lat rather than equal-area projections in our analysis. The fitted relationship between environmental parameters and occurrence probability differed only very little between the two projection types. We still recommend using equal-area projections to avoid possible bias. More importantly, our results suggest that the cell area and the proportion of a cell covered by land should be
NASA Workshop on Distributed Parameter Modeling and Control of Flexible Aerospace Systems
NASA Technical Reports Server (NTRS)
Marks, Virginia B. (Compiler); Keckler, Claude R. (Compiler)
1994-01-01
Although significant advances have been made in modeling and controlling flexible systems, there remains a need for improvements in model accuracy and in control performance. The finite element models of flexible systems are unduly complex and are almost intractable to optimum parameter estimation for refinement using experimental data. Distributed parameter or continuum modeling offers some advantages and some challenges in both modeling and control. Continuum models often result in a significantly reduced number of model parameters, thereby enabling optimum parameter estimation. The dynamic equations of motion of continuum models provide the advantage of allowing the embedding of the control system dynamics, thus forming a complete set of system dynamics. There is also increased insight provided by the continuum model approach.
NASA Astrophysics Data System (ADS)
Aghighi, H.; Trindet, J.; Wang, K.; Tarabalka, Y.; Lim, S.
2014-09-01
In the context of remote sensing image classification, Markov random fields (MRFs) have been used to combine both spectral and contextual information. The MRFs use a smoothing parameter to balance the contribution of the spectral versus spatial energies, which is often defined empirically. This paper proposes a framework to estimate the smoothing parameter using the probability estimates from support vector machines and the spatial class co-occurrence distribution. Furthermore, we construct a spatially weighted parameter to preserve the edges by using seven different edge detectors. The performance of the proposed methods is evaluated on two hyperspectral datasets recorded by the AVIRIS and ROSIS and a simulated ALOS PALSAR image. The experimental results demonstrated that the estimated smoothing parameter is optimal and produces a classified map with high accuracy. Moreover, we found that the Canny-based edge probability map preserved the contours better than others.
Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K
2016-03-15
Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations.
Visser, A; Moran, J E; Hillegonds, Darren; Singleton, M J; Kulongoski, Justin T; Belitz, Kenneth; Esser, B K
2016-03-15
Key characteristics of California groundwater systems related to aquifer vulnerability, sustainability, recharge locations and mechanisms, and anthropogenic impact on recharge are revealed in a spatial geostatistical analysis of a unique data set of tritium, noble gases and other isotopic analyses unprecedented in size at nearly 4000 samples. The correlation length of key groundwater residence time parameters varies between tens of kilometers ((3)H; age) to the order of a hundred kilometers ((4)Heter; (14)C; (3)Hetrit). The correlation length of parameters related to climate, topography and atmospheric processes is on the order of several hundred kilometers (recharge temperature; δ(18)O). Young groundwater ages that highlight regional recharge areas are located in the eastern San Joaquin Valley, in the southern Santa Clara Valley Basin, in the upper LA basin and along unlined canals carrying Colorado River water, showing that much of the recent recharge in central and southern California is dominated by river recharge and managed aquifer recharge. Modern groundwater is found in wells with the top open intervals below 60 m depth in the southeastern San Joaquin Valley, Santa Clara Valley and Los Angeles basin, as the result of intensive pumping and/or managed aquifer recharge operations. PMID:26803267
Precipitation classification at mid-latitudes in terms of drop size distribution parameters
NASA Astrophysics Data System (ADS)
Caracciolo, C.; Porcã¹, F.; Prodi, F.
2008-04-01
The drop size distribution (DSD) is a fundamental property of rainfall because the shape of the distribution reflects the physics of rain formation processes. Given the lack of studies on the DSD at mid-latitudes, the present work focuses on the microphysical characterization of precipitation events occurring in Italy, using two different types of disdrometer. A large number of different rain events was collected: they underwent microphysical analysis by computing the Z-R relationships, observing the average DSDs and DSD parameters, fitting the real distribution for different rainfall rate categories and applying convective (C) - stratiform (S) discrimination algorithms. A general agreement with past works at mid-latitudes is found both in the Z-R relationship and in DSD parameters. The rain distribution is well described by a gamma DSD and only in some cases (especially the light rain events) by an exponential DSD. Marked differences are observed in DSD parameters and Z-R relationships between C and S episodes. The use of disdrometers for areas covered by multiparametric radar is suggested and will be performed in the near future.
Numerical approach for the evaluation of Weibull distribution parameters for hydrologic purposes
NASA Astrophysics Data System (ADS)
Pierleoni, A.; Di Francesco, S.; Biscarini, C.; Manciola, P.
2016-06-01
In hydrology, the statistical description of low flow phenomena is very important in order to evaluate the available water resource especially in a river and the related values can be obviously considered as random variables, therefore probability distributions dealing with extreme values (maximum and/or minimum) of the variable play a fundamental role. Computational procedures for the estimation of the parameters featuring these distributions are actually very useful especially when embedded into analysis software [1][2] or as standalone applications. In this paper a computational procedure for the evaluation of the Weibull[3] distribution is presented focusing on the case when the lower limit of the distribution is not known or not set to a specific value a priori. The procedure takes advantage of the Gumbel[4] moment approach to the problem.
Angular distribution of cosmological parameters as a probe of space-time inhomogeneities
NASA Astrophysics Data System (ADS)
Carvalho, C. Sofia; Marques, Katrine
2016-08-01
We develop a method based on the angular distribution on the sky of cosmological parameters to probe the inhomogeneity of large-scale structure and cosmic acceleration. We demonstrate this method on the largest type Ia supernova (SN) data set available to date, as compiled by the Joint Light-curve Analysis (JLA) collaboration and, hence, consider the cosmological parameters that affect the luminosity distance. We divide the SN sample into equal surface area pixels and estimate the cosmological parameters that minimize the chi-square of the fit to the distance modulus in each pixel, hence producing maps of the cosmological parameters {ΩM,ΩΛ,H0} . In poorly sampled pixels, the measured fluctuations are mostly due to an inhomogeneous coverage of the sky by the SN surveys; in contrast, in well-sampled pixels, the measurements are robust enough to suggest a real fluctuation. We also measure the anisotropy of the parameters by computing the power spectrum of the corresponding maps of the parameters up to ℓ = 3. For an analytical toy model of an inhomogeneous ensemble of homogeneous pixels, we derive the backreaction term in the deceleration parameter due to the fluctuations of H0 across the sky and measure it to be of order 10-3 times the corresponding average over the pixels in the absence of backreaction. We conclude that, for the toy model considered, backreaction is not a viable dynamical mechanism to emulate cosmic acceleration.
Incidence, age distribution and complications of gonorrhoea in Sweden*
Gisslén, H.; Hellgren, L.; Starck, V.
1961-01-01
The incidence of gonorrhoea in Sweden has shown a tendency to increase in recent years, particularly in the age-groups 15-19 and 20-24 years. However, an extrapolation of the annual incidence curve to 1970 for the 15-19-year age-group suggests that some deceleration in that increase may be expected. Study of gonococcal complications seen at Göteborg hospitals during the period 1950-59 indicates that the frequency of gonococcal salpingitis is higher than had previously been reported; this is attributed to the inclusion in the material studied of patients from departments other than those exclusively concerned with the venereal diseases. The authors conclude that, in view of the high frequency of gonorrhoea in the young and of gonococcal complications, gonorrhoea in Sweden cannot be considered an unimportant public health problem. PMID:13705767
NASA Astrophysics Data System (ADS)
Dias, B.; Kerber, L. O.; Barbuy, B.; Santiago, B.; Ortolani, S.; Balbinot, E.
2014-01-01
Context. Stellar clusters in the Small Magellanic Cloud (SMC) are useful probes for studying the chemical and dynamical evolution of this neighbouring dwarf galaxy, enabling inspection of a large period covering over 10 Gyr. Aims: The main goals of this work are the derivation of age, metallicity, distance modulus, reddening, core radius, and central density profiles for six sample clusters, in order to place them in the context of the Small Cloud evolution. The studied clusters are AM 3, HW 1, HW 34, HW 40, Lindsay 2, and Lindsay 3; HW 1, HW 34, and Lindsay 2 are studied for the first time. Methods: Optical colour-magnitude diagrams (V,B - V CMDs) and radial density profiles were built from images obtained with the 4.1 m Southern Astrophysical Research (SOAR) telescope, reaching V ~ 23. The determination of structural parameters were carried out by applying King profile fitting. The other parameters were derived in a self-consistent way by means of isochrone fitting, which uses likelihood statistics to identify the synthetic CMDs that best reproduce the observed ones. Membership probabilities were determined comparing the cluster and control field CMDs. Completeness and photometric uncertainties were obtained by performing artificial star tests. Results: The results confirm that these clusters (except HW 34, identified as a field fluctuation) are intermediate-age clusters, with ages between 1.2 Gyr (Lindsay 3) and ~5.0 Gyr (HW 1). In particular HW 1, Lindsay 2 and Lindsay 3 are located in a region that we called West Halo, where studies of ages and metallicity gradients are still lacking. Moreover, Lindsay 2 was identified as a moderately metal-poor cluster with [Fe/H] = -1.4 ± 0.2 dex, lower than expected from the age-metallicity relation by Pagel & Tautvaisiene (1998). We also found distances varying from ~53 kpc to 66 kpc, compatible with the large depth of the SMC. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which
Semchyshyn, Halyna M; Lozinska, Liudmyla M; Miedzobrodzki, Jacek; Lushchak, Volodymyr I
2011-05-15
Fructose is commonly used as an industrial sweetener and has been excessively consumed in human diets in the last decades. High fructose intake is causative in the development of metabolic disorders, but the mechanisms underlying fructose-induced disturbances are under debate. Fructose compared to glucose has been found to be a more potent initiator of the glycation reaction. Therefore, we supposed that glucose and fructose might have different vital effects. Here we compare the effects of glucose and fructose on yeast cell viability and markers of carbonyl/oxidative stress. Analysis of the parameters in cells growing on glucose and fructose clearly reveals that yeast growing on fructose has higher levels of carbonyl groups in proteins, α-dicarbonyl compounds and reactive oxygen species. This may explain the observation that fructose-supplemented growth as compared with growth on glucose resulted in more pronounced age-related decline in yeast reproductive ability and higher cell mortality. The results are discussed from the point of view that fructose rather than glucose is more extensively involved in glycation and ROS generation in vivo, yeast aging and development of carbonyl/oxidative stress. It should be noted that carbohydrate restriction used in this study does not reveal a significant difference between markers of aging and carbonyl/oxidative stress in yeasts cultivated on glucose and fructose.
Huang, Feng; Jiang, Xiangqian; Yuan, Haiming; Yang, Hanning; Li, Siren; Sun, Xiudong
2016-04-01
A method to detect the full Stokes parameters utilizing a double-ring and Archimedes-curves distributed nanoslits plasmonic lenses is proposed. We demonstrate theoretically and numerically that both of these two plasmonic lenses can focus surface plasmon polaritons to centrally symmetric fields with subwavelength-sized focal spots under linear, elliptical, and circular polarization incidence. The intensity at the focal spots is modulated by the polarization state of incident light. Utilizing this intensity polarization sensitivity, the full Stokes parameters of incident light are detected by recoding only four intensities at the focal spots of these two plasmonic lenses. PMID:27192318
Huang, Feng; Jiang, Xiangqian; Yuan, Haiming; Yang, Hanning; Li, Siren; Sun, Xiudong
2016-04-01
A method to detect the full Stokes parameters utilizing a double-ring and Archimedes-curves distributed nanoslits plasmonic lenses is proposed. We demonstrate theoretically and numerically that both of these two plasmonic lenses can focus surface plasmon polaritons to centrally symmetric fields with subwavelength-sized focal spots under linear, elliptical, and circular polarization incidence. The intensity at the focal spots is modulated by the polarization state of incident light. Utilizing this intensity polarization sensitivity, the full Stokes parameters of incident light are detected by recoding only four intensities at the focal spots of these two plasmonic lenses.
SAC-SMA a priori parameter differences and their impact on distributed hydrologic model simulations
NASA Astrophysics Data System (ADS)
Zhang, Ziya; Koren, Victor; Reed, Seann; Smith, Michael; Zhang, Yu; Moreda, Fekadu; Cosgrove, Brian
2012-02-01
SummaryDeriving a priori gridded parameters is an important step in the development and deployment of an operational distributed hydrologic model. Accurate a priori parameters can reduce the manual calibration effort and/or speed up the automatic calibration process, reduce calibration uncertainty, and provide valuable information at ungauged locations. Underpinned by reasonable parameter data sets, distributed hydrologic modeling can help improve water resource and flood and flash flood forecasting capabilities. Initial efforts at the National Weather Service Office of Hydrologic Development (NWS OHD) to derive a priori gridded Sacramento Soil Moisture Accounting (SAC-SMA) model parameters for the conterminous United States (CONUS) were based on a relatively coarse resolution soils property database, the State Soil Geographic Database (STATSGO) (Soil Survey Staff, 2011) and on the assumption of uniform land use and land cover. In an effort to improve the parameters, subsequent work was performed to fully incorporate spatially variable land cover information into the parameter derivation process. Following that, finer-scale soils data (the county-level Soil Survey Geographic Database (SSURGO) ( Soil Survey Staff, 2011a,b), together with the use of variable land cover data, were used to derive a third set of CONUS, a priori gridded parameters. It is anticipated that the second and third parameter sets, which incorporate more physical data, will be more realistic and consistent. Here, we evaluate whether this is actually the case by intercomparing these three sets of a priori parameters along with their associated hydrologic simulations which were generated by applying the National Weather Service Hydrology Laboratory's Research Distributed Hydrologic Model (HL-RDHM) ( Koren et al., 2004) in a continuous fashion with an hourly time step. This model adopts a well-tested conceptual water balance model, SAC-SMA, applied on a regular spatial grid, and links to physically
Tomitaka, Shinichiro; Kawasaki, Yohei; Ide, Kazuki; Yamada, Hiroshi; Furukawa, Toshiaki A; Ono, Yutaka
2016-01-01
Background. Previous research has reported inconsistent evidence of the trajectory of depressive symptoms across the adult lifespan. We investigated how the distributions of each item score change with age and determined whether the trajectory of depressive symptoms varied with the scoring methods of the questionnaire. Methods. We analyzed data collected from 21,040 subjects who participated in the national survey in Japan. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). The CES-D has 20 items, each of which is scored in four grades of "rarely," "some," "much," and "most of the time." We used the exponential distribution model which fits the distributions of 16 negative symptom items of CES-D, with the probabilities of "some," "much," "most," and "rarely" expressed as P, Pr, Pr (2), and 1 - P × (r (2) + r + 1). Results. The distributions of the responses to 16 negative symptom items followed the common exponential model across all age groups. The mean of the estimated parameter r of 16 negative items showed a U-shape pattern, being high during 12-29 years, remaining low during 30-50 years, and then increasing again over 60 years. The trajectory of depressive symptom scores simulating the binary method was different from that of the empirical scores using the Likert method. Conclusions. Our findings show that the increase in the depressive symptoms score during older age is based on the increase of the parameter r. The differences in the scoring method may contribute to the different age-related patterns across the adult lifespan. PMID:26788427
Louzada, Francisco; Ramos, Pedro L; Perdoná, Gleici S C
2016-01-01
We have considered different estimation procedures for the unknown parameters of the extended exponential geometric distribution. We introduce different types of estimators such as the maximum likelihood, method of moments, modified moments, L-moments, ordinary and weighted least squares, percentile, maximum product of spacings, and minimum distance estimators. The different estimators are compared by using extensive numerical simulations. We discovered that the maximum product of spacings estimator has the smallest mean square errors and mean relative estimates, nearest to one, for both parameters, proving to be the most efficient method compared to other methods. Combining these results with the good properties of the method such as consistency, asymptotic efficiency, normality, and invariance we conclude that the maximum product of spacings estimator is the best one for estimating the parameters of the extended exponential geometric distribution in comparison with its competitors. For the sake of illustration, we apply our proposed methodology in two important data sets, demonstrating that the EEG distribution is a simple alternative to be used for lifetime data. PMID:27579052
Shape parameters and distribution of macroborings: St. Croix, US Virgin Islands
Jacobs, E.B.
1983-03-01
Many marine invertebrates that inhabit coral reefs excavate the coral substrate in order to create protective domiciles. In turn, the organisms comprising the coral-reef community display a pronounced biotic zonation that can be closely correlated to bathymetry. This study considers the distribution of these endolithic organisms covering a variety of reef habitats. Vast differences in the major environmental parameters have a profound effect upon the distribution patterns of macroboring organisms and govern the boring morphologies. Of these parameters, hydraulic energy has the strongest influences on the morphotypes and distributions of the macroborings. An equivalent macroboring assemblage dominated by sponges and bivalves prevails in both the shallow back-reef zone and the deep fore-reef zone, both of which are low-energy settings. Boring assemblages in more turbulent zones within the reef consist of polychaete and sipunculid worms, sea urchins, and barnacles, with sponges and bivalves less dominant and less abundant. Other environmental factors which may be important locally include: nutrient availability, photic energy, sediment size and sedimentation rate, competition for substrate, and predation pressure upon the live coral tissue. Shape parameters for different boring types are provided as a means of identification and as an indication of the environmental control upon boring shape. An understanding of the variability of boring types with respect to the ambient environment within modern reefs facilitates the use of borings as paleoenvironmental indicators within Cenozoic carbonate systems.
Ramos, Pedro L.; Perdoná, Gleici S. C.
2016-01-01
We have considered different estimation procedures for the unknown parameters of the extended exponential geometric distribution. We introduce different types of estimators such as the maximum likelihood, method of moments, modified moments, L-moments, ordinary and weighted least squares, percentile, maximum product of spacings, and minimum distance estimators. The different estimators are compared by using extensive numerical simulations. We discovered that the maximum product of spacings estimator has the smallest mean square errors and mean relative estimates, nearest to one, for both parameters, proving to be the most efficient method compared to other methods. Combining these results with the good properties of the method such as consistency, asymptotic efficiency, normality, and invariance we conclude that the maximum product of spacings estimator is the best one for estimating the parameters of the extended exponential geometric distribution in comparison with its competitors. For the sake of illustration, we apply our proposed methodology in two important data sets, demonstrating that the EEG distribution is a simple alternative to be used for lifetime data. PMID:27579052
Improving flash flood forecasting with distributed hydrological model by parameter optimization
NASA Astrophysics Data System (ADS)
Chen, Yangbo
2016-04-01
In China, flash food is usually regarded as flood occured in small and medium sized watersheds with drainage area less than 200 km2, and is mainly induced by heavy rains, and occurs in where hydrological observation is lacked. Flash flood is widely observed in China, and is the flood causing the most casualties nowadays in China. Due to hydrological data scarcity, lumped hydrological model is difficult to be employed for flash flood forecasting which requires lots of observed hydrological data to calibrate model parameters. Physically based distributed hydrological model discrete the terrain of the whole watershed into a number of grid cells at fine resolution, assimilate different terrain data and precipitation to different cells, and derive model parameteris from the terrain properties, thus having the potential to be used in flash flood forecasting and improving flash flood prediction capability. In this study, the Liuxihe Model, a physically based distributed hydrological model mainly proposed for watershed flood forecasting is employed to simulate flash floods in the Ganzhou area in southeast China, and models have been set up in 5 watersheds. Model parameters have been derived from the terrain properties including the DEM, the soil type and land use type, but the result shows that the flood simulation uncertainty is high, which may be caused by parameter uncertainty, and some kind of uncertainty control is needed before the model could be used in real-time flash flood forecastin. Considering currently many Chinese small and medium sized watersheds has set up hydrological observation network, and a few flood events could be collected, it may be used for model parameter optimization. For this reason, an automatic model parameter optimization algorithm using Particle Swam Optimization(PSO) is developed to optimize the model parameters, and it has been found that model parameters optimized even only with one observed flood events could largely reduce the flood
NASA Astrophysics Data System (ADS)
Teergele, Jane; Danai, Kourosh
2015-12-01
A method of sensor location selection is introduced for distributed parameter systems. In this method, the sensitivities of spatial outputs to model parameters are computed by a model and transformed via continuous wavelet transforms into the time-scale domain to characterise the shape attributes of output sensitivities and accentuate their differences. Regions are then sought in the time-scale plane wherein the wavelet coefficient of an output sensitivity surpasses all the others' as indication of the output sensitivity's distinctness. This yields a comprehensive account of identifiability each output provides to the model parameters as the basis of output selection. The proposed output selection strategy is demonstrated for a numerical case of pollutant dispersion by advection and diffusion in a two-dimensional area.
Development of a distributed-parameter mathematical model for simulation of cryogenic wind tunnels
NASA Technical Reports Server (NTRS)
Tripp, J. S.
1983-01-01
A one-dimensional distributed-parameter dynamic model of a cryogenic wind tunnel was developed which accounts for internal and external heat transfer, viscous momentum losses, and slotted-test-section dynamics. Boundary conditions imposed by liquid-nitrogen injection, gas venting, and the tunnel fan were included. A time-dependent numerical solution to the resultant set of partial differential equations was obtained on a CDC CYBER 203 vector-processing digital computer at a usable computational rate. Preliminary computational studies were performed by using parameters of the Langley 0.3-Meter Transonic Cryogenic Tunnel. Studies were performed by using parameters from the National Transonic Facility (NTF). The NTF wind-tunnel model was used in the design of control loops for Mach number, total temperature, and total pressure and for determining interactions between the control loops. It was employed in the application of optimal linear-regulator theory and eigenvalue-placement techniques to develop Mach number control laws.
A new algorithm for importance analysis of the inputs with distribution parameter uncertainty
NASA Astrophysics Data System (ADS)
Li, Luyi; Lu, Zhenzhou
2016-10-01
Importance analysis is aimed at finding the contributions by the inputs to the uncertainty in a model output. For structural systems involving inputs with distribution parameter uncertainty, the contributions by the inputs to the output uncertainty are governed by both the variability and parameter uncertainty in their probability distributions. A natural and consistent way to arrive at importance analysis results in such cases would be a three-loop nested Monte Carlo (MC) sampling strategy, in which the parameters are sampled in the outer loop and the inputs are sampled in the inner nested double-loop. However, the computational effort of this procedure is often prohibitive for engineering problem. This paper, therefore, proposes a newly efficient algorithm for importance analysis of the inputs in the presence of parameter uncertainty. By introducing a 'surrogate sampling probability density function (SS-PDF)' and incorporating the single-loop MC theory into the computation, the proposed algorithm can reduce the original three-loop nested MC computation into a single-loop one in terms of model evaluation, which requires substantially less computational effort. Methods for choosing proper SS-PDF are also discussed in the paper. The efficiency and robustness of the proposed algorithm have been demonstrated by results of several examples.
Mathematical results new and revisited on the distribution of groundwater age
NASA Astrophysics Data System (ADS)
Ginn, T. R.; Massoudieh, A.; Foglia, L.
2009-12-01
The equation governing the distribution of groundwater age under transient, 3D flow conditions is analyzed under several simplifying cases to illustrate some relations among groundwater age equations and some results about steady-state and transient age distributions. First linkages are made among the various groundwater age equations recently published, showing them all to be different simplifications of the same equation. The most basic analysis in 1D shows that groundwater age is at lease inverse-Gaussian distributed. More generally, steady state age moments, when they exist, are given by breakthrough curve moments and this allows us to use the temporal moment results from the solute transport literature as steady state age moments. In particular, age moment equations with arbitrary diffusive mass transfer (two-domain, radial microscopic, powerlaw) at steady state are already available as the temporal flux moment equations for solute transport under analogous boundary conditions. Lastly transient simulations of age in 1D are calculated to illustrate several aspects of the evolution of groundwater age distributions in time in the presences of multidomain diffusive transport.
Xu, Yihuan; Iglewicz, Boris; Chervoneva, Inna
2014-07-01
The g - and - h distributional family is generated from a relatively simple transformation of the standard normal and can approximate a broad spectrum of distributions. Consequently, it is easy to use in simulation studies and has been applied in multiple areas, including risk management, stock return analysis and missing data imputation studies. A rapidly convergent quantile based least squares (QLS) estimation method to fit the g - and - h distributional family parameters is proposed and then extended to a robust version. The robust version is then used as a more general outlier detection approach. Several properties of the QLS method are derived and comparisons made with competing methods through simulation. Real data examples of microarray and stock index data are used as illustrations. PMID:24665144
Correlation of age with distribution of periodontitis-related bacteria in Japanese dogs.
Hirai, Norihiko; Shirai, Mitsuyuki; Kato, Yukio; Murakami, Masaru; Nomura, Ryota; Yamasaki, Yoshie; Takahashi, Soraaki; Kondo, Chihiro; Matsumoto-Nakano, Michiyo; Nakano, Kazuhiko; Asai, Fumitoshi
2013-07-31
We analyzed the distribution of 11 periodontitis-related bacterial species in dental plaque collected from 176 Japanese dogs divided into young (less than 2 years of age), middle-aged (2-7 years of age) and elderly (more than 8 years of age) groups using a polymerase chain reaction method. Clinical examination revealed that no dogs in the young group were affected by periodontitis, whereas the rates for gingivitis and periodontitis were high in the middle-aged and elderly groups. In addition, the total numbers of bacterial species in the middle-aged and elderly groups were significantly greater than in the young group. Our findings suggest that age is an important factor associated with the distribution of periodontitis-related bacteria and periodontal conditions in dogs.
The Globular Cluster System of NGC 5128: Ages, Metallicities, Kinematics and Structural Parameters
NASA Astrophysics Data System (ADS)
Woodley, K. A.; Gómez, M.
2010-10-01
We review our recent studies of the globular cluster system of NGC 5128. First, we have obtained low-resolution, high signal-to-noise spectroscopy of 72 globular clusters using Gemini-S/GMOS to obtain the ages, metallicities, and the level of alpha enrichment of the metal-poor and metal-rich globular cluster subpopulations. Second, we have explored the rotational signature and velocity dispersion of the galaxy's halo using over 560 globular clusters with radial velocity measurements. We have also compared the dependence of these properties on galactocentric distance and globular cluster age and metallicity. Using globular clusters as tracer objects, we have analyzed the mass, and mass-to-light ratio of NGC 5128. Last, we have measured the structural parameters, such as half-light radii, of over 570 globular clusters from a superb 1.2-square-degree Magellan/IMACS image. We will present the findings of these studies and discuss the connection to the formation and evolution of NGC 5128.
Effects of Forest Bathing on Cardiovascular and Metabolic Parameters in Middle-Aged Males.
Li, Qing; Kobayashi, Maiko; Kumeda, Shigeyoshi; Ochiai, Toshiya; Miura, Takashi; Kagawa, Takahide; Imai, Michiko; Wang, Zhiyu; Otsuka, Toshiaki; Kawada, Tomoyuki
2016-01-01
In the present study, we investigated the effects of a forest bathing on cardiovascular and metabolic parameters. Nineteen middle-aged male subjects were selected after they provided informed consent. These subjects took day trips to a forest park in Agematsu, Nagano Prefecture, and to an urban area of Nagano Prefecture as control in August 2015. On both trips, they walked 2.6 km for 80 min each in the morning and afternoon on Saturdays. Blood and urine were sampled before and after each trip. Cardiovascular and metabolic parameters were measured. Blood pressure and pulse rate were measured during the trips. The Japanese version of the profile of mood states (POMS) test was conducted before, during, and after the trips. Ambient temperature and humidity were monitored during the trips. The forest bathing program significantly reduced pulse rate and significantly increased the score for vigor and decreased the scores for depression, fatigue, anxiety, and confusion. Urinary adrenaline after forest bathing showed a tendency toward decrease. Urinary dopamine after forest bathing was significantly lower than that after urban area walking, suggesting the relaxing effect of the forest bathing. Serum adiponectin after the forest bathing was significantly greater than that after urban area walking. PMID:27493670
Effects of Forest Bathing on Cardiovascular and Metabolic Parameters in Middle-Aged Males
Kobayashi, Maiko; Kumeda, Shigeyoshi; Ochiai, Toshiya; Miura, Takashi; Imai, Michiko; Wang, Zhiyu; Otsuka, Toshiaki; Kawada, Tomoyuki
2016-01-01
In the present study, we investigated the effects of a forest bathing on cardiovascular and metabolic parameters. Nineteen middle-aged male subjects were selected after they provided informed consent. These subjects took day trips to a forest park in Agematsu, Nagano Prefecture, and to an urban area of Nagano Prefecture as control in August 2015. On both trips, they walked 2.6 km for 80 min each in the morning and afternoon on Saturdays. Blood and urine were sampled before and after each trip. Cardiovascular and metabolic parameters were measured. Blood pressure and pulse rate were measured during the trips. The Japanese version of the profile of mood states (POMS) test was conducted before, during, and after the trips. Ambient temperature and humidity were monitored during the trips. The forest bathing program significantly reduced pulse rate and significantly increased the score for vigor and decreased the scores for depression, fatigue, anxiety, and confusion. Urinary adrenaline after forest bathing showed a tendency toward decrease. Urinary dopamine after forest bathing was significantly lower than that after urban area walking, suggesting the relaxing effect of the forest bathing. Serum adiponectin after the forest bathing was significantly greater than that after urban area walking. PMID:27493670
Long, A.J.; Putnam, L.D.
2009-01-01
Convolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon (CFC) and tritium (3H) data are available. We show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined. As an example, the model was applied to water from a pumped well open to the Madison aquifer in central USA with input functions of CFC-11, CFC-12, CFC-113, and 3H, and was calibrated to several samples collected during a 16-year period. A bimodal age distribution was modeled to represent quick and slow flow less than 50 years old. The effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow. Quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0-2 and 26-41 years, respectively. The fraction of long-term flow (>50 years) was estimated but was not dateable. The different tracers had different degrees of influence on parameter estimation and uncertainty assessments, where 3H was the most critical, and CFC-113 was least influential.
NASA Astrophysics Data System (ADS)
Long, Andrew J.; Putnam, Larry D.
2009-10-01
SummaryConvolution modeling is useful for investigating the temporal distribution of groundwater age based on environmental tracers. The framework of a quasi-transient convolution model that is applicable to two-domain flow in karst aquifers is presented. The model was designed to provide an acceptable level of statistical confidence in parameter estimates when only chlorofluorocarbon (CFC) and tritium ( 3H) data are available. We show how inverse modeling and uncertainty assessment can be used to constrain model parameterization to a level warranted by available data while allowing major aspects of the flow system to be examined. As an example, the model was applied to water from a pumped well open to the Madison aquifer in central USA with input functions of CFC-11, CFC-12, CFC-113, and 3H, and was calibrated to several samples collected during a 16-year period. A bimodal age distribution was modeled to represent quick and slow flow less than 50 years old. The effects of pumping and hydraulic head on the relative volumetric fractions of these domains were found to be influential factors for transient flow. Quick flow and slow flow were estimated to be distributed mainly within the age ranges of 0-2 and 26-41 years, respectively. The fraction of long-term flow (>50 years) was estimated but was not dateable. The different tracers had different degrees of influence on parameter estimation and uncertainty assessments, where 3H was the most critical, and CFC-113 was least influential.
Martian channels and valleys: Their characteristics, distribution, and age
Carr, M.H.; Clow, G.D.
1981-01-01
All Martian channels and valleys visible at a resolution of 125 to 300 meters between 65??N and 65??S were mapped at a scale of 1:5,000,000 and the maps then digitized. Correlations of valley presence with other surface features show that almost all valleys are in the old cratered terrain. preferentially in areas of low albedo, low violet/red ratios, and high elevation. The networks are open, the individual drainage basins are small relative to Earth, and large distances separate the basins, features which all suggest an immature drainage system. The simplest explanation of the correlations and the restriction of valley networks to old terrain is that the channels themselves are old, and that the climatic conditions necessary for their formation did not prevail for long after the decline in the cratering rate around 3.9 billion years ago. Two types of outflow channel are distinguished: unconfined, in which broad swaths of terrain are scoured, and confined, in which flow is restricted to discrete channels. The outflow channels have a wide range of ages and may form under present climatic conditions. Fretted channels are largely restrited to two latitude belts centered on 40??N and 45??S, where relatively rapid erosion along escarpments results from mass wasting. They probably form by enlargement of preexisting channels by escarpment retreat. ?? 1981.
Olsen, Anya
2012-01-01
Policymakers have proposed increases to the early eligibility age (EEA) and/or full retirement age (FRA) to address increasing life expectancy and Social Security solvency issues. This analysis uses the Social Security Administration's Modeling Income in the Near Term, version 6 (MINT6) model to compare three retirement-age increases suggested by the Social Security Advisory Board: increase the gap between the EEA and FRA by raising only the FRA, increase both the EEA and FRA to maintain a 4-year gap between them, and increase both the EEA and FRA to maintain a 5-year gap between them. Although all three options would improve system solvency by similar proportions, their effect on individual beneficiaries in the future would vary. Benefit reductions are greater under the proposals with more months between the EEA and FRA, while the option that maintains a 4-year gap results in benefit increases for some beneficiaries compared with current law. PMID:23397744
NASA Astrophysics Data System (ADS)
Krueger, T.
2012-04-01
Observational uncertainties are a notably under-researched area in environmental science, despite their impact on process understanding, model prediction (via the input, calibration and validation stages) and decision making. In this paper I focus on water quality parameters, such as sediment, phosphorus, nitrogen, chloride and oxygen concentrations, which are routinely monitored by environmental regulators to assess the status of surface waters and inform water resources management. This assessment is typically done based on a low temporal monitoring resolution, which in the UK, for example, is fortnightly or monthly so that no more than 12-26 samples per year are typically available. This sampling pattern introduces an unknown bias to the empirical frequency distribution of the parameters, particularly those that are highly variable in time, such as sediment and phosphorus. This bias translates into uncertainty about the statistical moments and percentiles which are ultimately compared to environmental standards or used to drive, calibrate and validate models. In this paper I estimate this uncertainty probabilistically comparing three Bayesian inference models: (1) estimating the parameters of a theoretical frequency distribution, (2) averaging over multiple hypotheses of the frequency distribution, (3) the Bayesian Bootstrap. Uncertainty estimates are propagated through to percentiles of key water quality parameters for practical cases of rural pollution management in the UK and compared to existing standards to illustrate the impact of observational uncertainty on the assessment of surface waters. I also demonstrate a case of model calibration against these uncertain data. The three inference models compared all have limitations and rely on more or less subjective assumptions about the data not collected which are illustrated and discussed. As the science here offers multiple solutions, I will argue that the methodological choice is best made together with
NASA Astrophysics Data System (ADS)
Malyarenko, Dariya Ivanovna
The characterization of narrow distributions of structural and motional parameters, and their evolution during the broad glass transition, is performed for deuterated PAMAM dendrimer salts using solid state NMR. The broadening of deuteron quadrupole echo (QE) lineshapes is consistent with the presence of narrow hydrogen bond length distribution (σr < 0.25 Å) at the spacer amide and branching tertiary amine sites. The temperature dependent averaging of the experimental lineshapes is explained on the basis of fast planar librations in the dendrimer interior, and fast rotation and intermediate regime libration (in an asymmetric cone) of the dendrimer termini. The amplitudes of libration are temperature dependent and higher for low generation dendrimers, while librational rates show Arrhenius behavior only within the glass transition region. In this region, the width of log-normal distribution of rates increases with temperature at sites associated with chlorine counterions. The largest distributions are still less than one order of magnitude wide, unlike the dendrimer in solution or the linear polymers. Interpenetrated low generations (G < 3), uniform intermediate generations (G = 3-5) with surface network, and backfolded high generations (G > 5), are distinguished by interior and termini dynamics. In the regime of fast motion QE lineshapes are highly sensitive to the presence of narrow structural and motional parameter distributions, and provide constraints on motional geometry independent of rates. The precise characterization of narrow log-normal rate distributions in the intermediate regime can be done using 2H magic angle spinning (MAS). Deuteron inversion-recovery techniques provide quantitative information on the rates of fast motion. For PAMAM salts, the influence of narrow distributions of structural and motional parameters, and fast planar libration, is negligible for distance determination using Rotational Echo Double Resonance (REDOR). The discrimination
Paleoclimate signals and age distributions from 41 public water works in the Netherlands
NASA Astrophysics Data System (ADS)
Broers, Hans Peter; de Weert, Jasperien; Sueltenfuss, Juergen; Aeschbach-Hertig, Werner; Vonhof, Hubert; Casteleijns, Jeroen
2015-04-01
Knowing the age distribution of water abstracted from public water supply wells is of prime importance to ensure customer trust and to underpin predictions of water quality evolution in time. Especially, age distributions enable the assessment of the vulnerability of well fields, both in relation to surface sources of contamination as in relation to subsurface sources, such as possibly related to shale gas extraction. We sampled the raw water of 41 large public supply well fields which represents a mixture of groundwaters and used the a discrete travel time distribution model (DTTDM, Visser et al. 2013, WRR) in order to quantify the age distribution of the mixture. Measurements included major ion chemistry, 3H, 3He, 4He, 18O, 2H, 14C, 13CDIC and 13CCH4 and the full range of noble gases. The heavier noble gases enable the calculation of the Noble Gas Temperature (NGT) which characterizes the temperature of past recharge conditions. The 14C apparent age of each mixture was derived correcting for dead carbon sources and included carbonate dissolution and methanogenesis as the defining processes. The DTTDM used the 3H and 4He concentrations, the 14C apparent age and the NGT as the four distinctive tracers to estimate the age distributions. The use of 18O was less effective because the processes that led to more enriched values are too uncertain . Especially 4He and NGT provide extra information on the older part of the age distributions and showed that the 14C apparent ages are often the result of mixing of waters ranging between 2.000 and 35.000 years old, instead of being discrete ages with a limited .variance as sometimes assumed. The results show a large range of age distributions, comprising vulnerable well fields with >60% young water (< 100 yrs) and well-protected well fields with >85% very old groundwater (> 25 kyrs) and all forms of TTD's in between. The age distributions are well in correspondence with the hydrogeological setting of the well fields; all well
Paleoclimate Signals and Age Distributions from 41 Public Water Works in the Netherlands
NASA Astrophysics Data System (ADS)
Broers, H. P.; Weert, J. D.; Sültenfuß, J.; Aeschbach, W.; Vonhof, H.; Casteleijns, J.
2015-12-01
Knowing the age distribution of water abstracted from public water supply wells is of prime importance to ensure customer trust and to underpin predictions of water quality evolution in time. Especially, age distributions enable the assessment of the vulnerability of well fields, both in relation to surface sources of contamination as in relation to subsurface sources, such as possibly related to shale gas extraction. We sampled the raw water of 41 large public supply well fields which represents a mixture of groundwaters and used the a discrete travel time distribution model (DTTDM, Visser et al. 2013, WRR) in order to quantify the age distribution of the mixture. Measurements included major ion chemistry, 3H, 3He, 4He, 18O, 2H, 14C, 13CDIC and 13CCH4 and the full range of noble gases. The heavier noble gases enable the calculation of the Noble Gas Temperature (NGT) which characterizes the temperature of past recharge conditions. The 14C apparent age of each mixture was derived correcting for dead carbon sources. The DTTDM used the 3H and 4He concentrations, the 14C apparent age and the NGT as the four distinctive tracers to estimate the age distributions. Especially 4He and NGT provide extra information on the older part of the age distributions and showed that the 14C apparent ages are often the result of mixing of waters ranging between 2.000 and 35.000 years old, instead of being discrete ages with a limited .variance as sometimes assumed.The results show a large range of age distributions, comprising vulnerable well fields with >60% young water (< 100 yrs) and well-protected well fields with >85% very old groundwater (> 25 kyrs) and all forms of TTD's in between. The age distributions are well in correspondence with the hydrogeological setting of the well fields; all well fields with an age distribution skewed towards older ages are in the Roer Valley Graben structure, where fluvial and marine aquitards provide protection from recent recharge. Especially
NASA Astrophysics Data System (ADS)
Donovan, J.; Jordan, T. H.
2010-12-01
Aftershocks are often used to delineate the mainshock rupture zone retrospectively. In aftershock forecasting on the other hand, the problem is to use mainshock rupture area to determine the aftershock zone prospectively. The procedures for this type of prediction are not as well developed and have been restricted to simple parameterizations such as the Utsu-Seki (1955) scaling relation between mainshock energy and aftershock area (Ogata and Zhueng, 2006). With a focus on improving current forecasting methods, we investigate the relationship between spatial source parameters that can be rapidly computed (spatial centroid and characteristic dimensions) and corresponding spatial measures of the aftershock distribution. For a set of about 30 large events, we either extracted source parameters from the McGuire et al (2002) finite moment tensor (FMT) catalog, or computed them from the online SRCMOD database (Mai, 2004). We identified aftershocks with windowing and scale-free methods, and computed both L1 and L2 measures of their distributions. Our comparisons produce scaling relations among the characteristic dimensions that can be used to initiate aftershock forecasts. By using rapidly-determined source parameters, we can decrease the forecasting latency and thus improve the probability gain of the forecasting methods.
Nonlinear and distributed parameter models of the mini-mast truss
NASA Technical Reports Server (NTRS)
Taylor, Lawrence W., Jr.
1989-01-01
Large spacecraft such as Space Station Freedom employ large trusses in their construction. The structural dynamics of such trusses often exhibit nonlinear behavior and little damping which can impact significantly the performance of control systems. The Mini-MAST truss was constructed to research such structural dynamics and control systems. The Mini-MAST truss is an object of study for the guest investigator program as part of NASA's controls-structures interaction program. The Mini-MAST truss is deployable and about 65 ft long. Although the bending characteristics of the Mini-MAST truss are essentially linear, the angular deflection under torsional loading has exhibited significant hysteresis and nonlinear stiffness. It is the purpose to develop nonlinear and distributed parameter models of the truss and to compare the model dynamics with actual measurements. Distributed parameter models have the advantage of requiring fewer model parameters. A tangent function is used to describe the nonlinear stiffness in torsion, partly because of the convenience of its easily expressed inverse. Hysteretic slip elements are introduced and extended to a continuum to account for the observed hysteresis in torsion. The contribution of slipping to the structural damping is analyzed and found to be strongly dependent on the applied loads. Because of the many factors which affect the damping and stiffness in a truss, it is risky to assume linearity.
NASA Astrophysics Data System (ADS)
Zhao, Youxuan; Qiu, Yanjun; Jacobs, Laurence J.; Qu, Jianmin
2016-02-01
As a longitudinal wave propagates through a linearly elastic solid with distributed cracks, the solid is subjected to cyclic tension and compression. During the tensile cycles, a crack might be open and its faces are traction-free. During the compressive cycles, a crack might be closed and its faces are in contact. Such contact may also be frictional because of crack face roughness. Such tension and compression asymmetry causes acoustic nonlinearity. This paper develops a micromechanics model that relates the crack density to the acoustic nonlinearity parameter. The model is based on a micromechanics homogenization of the cracked solid under dynamic loading. It is shown that the acoustic nonlinearity parameter is proportional to the crack density. Furthermore, the acoustic nonlinearity parameter also depends on the frequency of the wave motion, and the coefficient of friction of the crack faces. Unlike the second harmonic generated by dislocations, the amplitude of the second harmonic due to crack face contact is proportional to the amplitude of the fundamental frequency. To validate the micromechanics model, the finite element method is used to simulate wave propagation in solid with randomly distributed microcracks. The micromechanics model predictions agree well with the finite element simulation results.
NASA Astrophysics Data System (ADS)
Mohammadi, Hiwa; Bayrak, Yusuf
2016-04-01
The Gumbel's third asymptotic distribution (GIII) of the extreme value method is employed to evaluate the earthquake hazard parameters in the Iranian Plateau. This research quantifies spatial mapping of earthquake hazard parameters like annual and 100-year mode beside their 90 % probability of not being exceeded (NBE) in the Iranian Plateau. Therefore, we used a homogeneous and complete earthquake catalogue during the period 1900-2013 with magnitude M w ≥ 4.0, and the Iranian Plateau is separated into equal area mesh of 1° late × 1° long. The estimated result of annual mode with 90 % probability of NBE is expected to exceed the values of M w 6.0 in the Eastern part of Makran, most parts of Central and East Iran, Kopeh Dagh, Alborz, Azerbaijan, and SE Zagros. The 100-year mode with 90 % probability of NBE is expected to overpass the value of M w 7.0 in the Eastern part of Makran, Central and East Iran, Alborz, Kopeh Dagh, and Azerbaijan. The spatial distribution of 100-year mode with 90 % probability of NBE uncovers the high values of earthquake hazard parameters which are frequently connected with the main tectonic regimes of the studied area. It appears that there is a close communication among the seismicity and the tectonics of the region.
NASA Astrophysics Data System (ADS)
Gautheron, Cécile; Balout, Hilal; Roques, Jérôme; Allard, Thierry; Morin, Guillaume; Tassan-Got, Laurent
2016-04-01
At the Earth's surface, hematite and goethite are common minerals occurring in soils and sediments, including ores. The understanding of the corresponding alteration and weathering processes relies on our ability to perform the dating of formation of these minerals. Two relevant and recent dating methods have been developed, which are related to (U-Th)/He and (U-Th)/Ne geochronometers. They are based on accumulation of 4He and 21Ne associated with the alpha decay of U and Th. Both methods are of particular interest because of possible He and Ne retention over geological ages at surface temperature. However, because of different atomic radius between He and Ne, retention behavior of these two species can be quite different. Moreover, the dating procedure is particularly challenging because of the small crystals size and frequent polycrystalline structure of hematite and goethite. As a matter of fact, some uncertainty exists about He and Ne diffusion parameters, due to the nanometric to micrometric crystal size of natural iron oxide mineral. Accordingly, the determination of (U-Th)/He and (U-Th)/Ne ages requires the understanding of He and Ne production and retention (which may be partial) in iron oxide crystals. In this study, we theoretically investigate and discuss for the first time the age evolution for pure goethite and hematite crystals with different thermal histories, including reheating to simulate burial. The aim is to quantify the He and/or Ne loss by ejection and diffusion for crystals of different morphology and polycrystalline structures. This will allow one to provide some correction factor for the age. For this purpose, we used new He and Ne diffusion coefficients obtained by multi-scale theoretical approach using Density Functional Theory (DFT) (Balout et al., submitted, a,b), associated with 3D production and diffusion code (Gautheron and Tassan-Got, 2010). The impact of Multi Diffusion Domains simulating polycrystalline structure has been
Jevtić, Aleksandar; Gutiérrez, Álvaro
2011-01-01
Swarms of robots can use their sensing abilities to explore unknown environments and deploy on sites of interest. In this task, a large number of robots is more effective than a single unit because of their ability to quickly cover the area. However, the coordination of large teams of robots is not an easy problem, especially when the resources for the deployment are limited. In this paper, the Distributed Bees Algorithm (DBA), previously proposed by the authors, is optimized and applied to distributed target allocation in swarms of robots. Improved target allocation in terms of deployment cost efficiency is achieved through optimization of the DBA’s control parameters by means of a Genetic Algorithm. Experimental results show that with the optimized set of parameters, the deployment cost measured as the average distance traveled by the robots is reduced. The cost-efficient deployment is in some cases achieved at the expense of increased robots’ distribution error. Nevertheless, the proposed approach allows the swarm to adapt to the operating conditions when available resources are scarce. PMID:22346677
EFFECTS OF MIXING AND AGING ON WATER QUALITY IN DISTRIBUTION SYSTEM STORAGE FACILITIES
Aging of water in distribution system storage facilities can lead to deterioration of the water quality due to loss of disinfectant residual and bacterial regrowth. Facilities should be operated to insure that the age of the water is not excessive taking into account the quality...
NASA Astrophysics Data System (ADS)
Gronz, O.; Casper, M. C.; Gemmar, P.
2009-04-01
In mesoscale water balance models, the relevant hydrological processes in runoff generation are abstractly simulated. One aspect of this abstraction is grouping areas to model elements, each of which simulated individually, resulting in a set of model elements. A single element might be homogeneous by means of a certain characteristics, e. g. land use, but it might also be heterogeneous considering a different feature, e. g. slope. Due to this abstraction and grouping, the processes cannot be described in detail by physical laws and thus, parameters to be calibrated will occur in the model's assumptions. Typically, the same value is used for all elements of a catchment, mainly due to the quantity of all possible parameter value configurations. Thus, the spatial distribution of the occurrence of processes and their specific strength, which can be observed in the real catchment, will not be represented by the model. The model might rather represent the mean behavior. As a result, the distribution of water in the model might not match the real system. This strongly limits the applicability of the model and it increases the complexity of calibration. To support a spatial distributed parameterization of a model, new sources of information need to be incorporated. One way of incorporating additional information is the usage of hydrological soil maps, which are available today. They indicate the potentially dominant runoff processes like Horton overland flow, subsurface flow, deep percolation etc. These maps are e. g. generated by artificial neural networks using various different sources like geological maps, digital terrain models and characteristics derived from this model, land use maps etc. An interdisciplinary project has started to integrate these maps in the calibration process. The main aim is to represent the spatial distribution shown by the map in the model. An initial idea is to find parameter prototypes for each of the runoff processes. These parameter
Levitas, E; Lunenfeld, E; Weisz, N; Friger, M; Potashnik, G
2007-04-01
This study evaluates retrospectively the relationship between age and semen parameters among men with normal sperm concentration. It was based on computerized data and performed in an Academic Fertility and IVF Unit. Six thousand and twenty-two semen samples with sperm concentrations of >or=20 x 10(6) ml(-1) were examined according to WHO criteria and analysed in relation to patients' age. For each age group, mean values +/- SD of semen volume, sperm concentration, percentage of motile spermatozoa, normal morphology, acrosome index, total sperm count/ejaculate, total motile sperm count/ejaculate and sexual abstinence duration were examined. A peak semen volume of 3.51 +/- 1.76 ml(-1) was observed at age >or=30 to <35 years and a lowest volume of 2.21 +/- 1.23 ml(-1) was observed at age >or=55 years (P<0.05). Sperm motility was found to be inversely related to age with peak motility of 44.39 +/- 20.69% at age <25 years and lowest motility of 24.76 +/- 18.27% at age >or=55 years (P<0.05). A reduction of 54% was observed for total motile sperm, between values of 103.34 +/- 107 x 10(6) at age >or=30 to <35 years and 46.68 +/- 53.73 x 10(6) (P<0.05) at age >55 years. A statistically significant and inverse relationship was observed between semen volume, sperm quality and patient age, in spite of prolonged sexual abstinence duration. Top sperm parameters were observed at age >or=30 to <35 years, while the most significant reduction in sperm parameters occurred after the age of 55 years.
An approximation theory for the identification of nonlinear distributed parameter systems
NASA Technical Reports Server (NTRS)
Banks, H. T.; Reich, Simeon; Rosen, I. G.
1988-01-01
An abstract approximation framework for the identification of nonlinear distributed parameter systems is developed. Inverse problems for nonlinear systems governed by strongly maximal monotone operators (satisfying a mild continuous dependence condition with respect to the unknown parameters to be identified) are treated. Convergence of Galerkin approximations and the corresponding solutions of finite dimensional approximating identification problems to a solution of the original finite dimensional identification problem is demonstrated using the theory of nonlinear evolution systems and a nonlinear analog of the Trotter-Kato approximation result for semigroups of bounded linear operators. The nonlinear theory developed here is shown to subsume an existing linear theory as a special case. It is also shown to be applicable to a broad class of nonlinear elliptic operators and the corresponding nonlinear parabolic partial differential equations to which they lead. An application of the theory to a quasilinear model for heat conduction or mass transfer is discussed.
An approximation theory for the identification of nonlinear distributed parameter systems
NASA Technical Reports Server (NTRS)
Banks, H. T.; Reich, Simeon; Rosen, I. G.
1990-01-01
An abstract approximation framework for the identification of nonlinear distributed parameter systems is developed. Inverse problems for nonlinear systems governed by strongly maximal monotone operators (satisfying a mild continuous dependence condition with respect to the unknown parameters to be identified) are treated. Convergence of Galerkin approximations and the corresponding solutions of finite dimensional approximating identification problems to a solution of the original finite dimensional identification problem is demonstrated using the theory of nonlinear evolution systems and a nonlinear analog of the Trotter-Kato appproximation result for semigroups of bounded linear operators. The nonlinear theory developed here is shown to subsume an existing linear theory as a special case. It is also shown to be applicable to a broad class of nonlinear elliptic operators and the corresponding nonlinear parabolic partial differential equations to which they lead. An application of the theory to a quasilinear model for heat conduction or mass transfer is discussed.
NASA Astrophysics Data System (ADS)
Miao, Changyun; Shi, Boya; Li, Hongqiang
2008-12-01
A human physiological parameters intelligent clothing is researched with FBG sensor technology. In this paper, the principles and methods of measuring human physiological parameters including body temperature and heart rate in intelligent clothing with distributed FBG are studied, the mathematical models of human physiological parameters measurement are built; the processing method of body temperature and heart rate detection signals is presented; human physiological parameters detection module is designed, the interference signals are filtered out, and the measurement accuracy is improved; the integration of the intelligent clothing is given. The intelligent clothing can implement real-time measurement, processing, storage and output of body temperature and heart rate. It has accurate measurement, portability, low cost, real-time monitoring, and other advantages. The intelligent clothing can realize the non-contact monitoring between doctors and patients, timely find the diseases such as cancer and infectious diseases, and make patients get timely treatment. It has great significance and value for ensuring the health of the elders and the children with language dysfunction.
Costabel, Stephan; Yaramanci, Ugur
2013-01-01
[1] For characterizing water flow in the vadose zone, the water retention curve (WRC) of the soil must be known. Because conventional WRC measurements demand much time and effort in the laboratory, alternative methods with shortened measurement duration are desired. The WRC can be estimated, for instance, from the cumulative pore size distribution (PSD) of the investigated material. Geophysical applications of nuclear magnetic resonance (NMR) relaxometry have successfully been applied to recover PSDs of sandstones and limestones. It is therefore expected that the multiexponential analysis of the NMR signal from water-saturated loose sediments leads to a reliable estimation of the WRC. We propose an approach to estimate the WRC using the cumulative NMR relaxation time distribution and approximate it with the well-known van-Genuchten (VG) model. Thereby, the VG parameter n, which controls the curvature of the WRC, is of particular interest, because it is the essential parameter to predict the relative hydraulic conductivity. The NMR curves are calibrated with only two conventional WRC measurements, first, to determine the residual water content and, second, to define a fixed point that relates the relaxation time to a corresponding capillary pressure. We test our approach with natural and artificial soil samples and compare the NMR-based results to WRC measurements using a pressure plate apparatus and to WRC predictions from the software ROSETTA. We found that for sandy soils n can reliably be estimated with NMR, whereas for samples with clay and silt contents higher than 10% the estimation fails. This is the case when the hydraulic properties of the soil are mainly controlled by the pore constrictions. For such samples, the sensitivity of the NMR method for the pore bodies hampers a plausible WRC estimation. Citation: Costabel, S., and U. Yaramanci (2013), Estimation of water retention parameters from nuclear magnetic resonance relaxation time distributions, Water
An analysis of the size distribution of Italian firms by age
NASA Astrophysics Data System (ADS)
Cirillo, Pasquale
2010-02-01
In this paper we analyze the size distribution of Italian firms by age. In other words, we want to establish whether the way that the size of firms is distributed varies as firms become old. As a proxy of size we use capital. In [L.M.B. Cabral, J. Mata, On the evolution of the firm size distribution: Facts and theory, American Economic Review 93 (2003) 1075-1090], the authors study the distribution of Portuguese firms and they find out that, while the size distribution of all firms is fairly stable over time, the distributions of firms by age groups are appreciably different. In particular, as the age of the firms increases, their size distribution on the log scale shifts to the right, the left tails becomes thinner and the right tail thicker, with a clear decrease of the skewness. In this paper, we perform a similar analysis with Italian firms using the CEBI database, also considering firms’ growth rates. Although there are several papers dealing with Italian firms and their size distribution, to our knowledge a similar study concerning size and age has not been performed yet for Italy, especially with such a big panel.
PATTERNS OF ROOT GROWTH, TURNOVER, AND DISTRIBUTION IN DIFFERENT AGED PONDEROSA PINE STANDS
The objectives of this study are to examine the spatial distribution of roots in relation to canopy size and tree distribution, and to determine if rates of fine root production and turnover are similar in the different aged stands. During the fall of 1998, 54 clear plexiglass t...
Creating Composite Age Groups to Smooth Percentile Rank Distributions of Small Samples
ERIC Educational Resources Information Center
Lopez, Francesca; Olson, Amy; Bansal, Naveen
2011-01-01
Individually administered tests are often normed on small samples, a process that may result in irregularities within and across various age or grade distributions. Test users often smooth distributions guided by Thurstone assumptions (normality and linearity) to result in norms that adhere to assumptions made about how the data should look. Test…
Distributed parameter model for characterizing magnetic crosstalk in a fiber optic current sensor.
Cheng, Song; Guo, Zhi-Zhong; Zhang, Guo-Qing; Yu, Wen-Bin; Shen, Yan
2015-12-01
The effects of magnetic crosstalk on a fiber optic current sensor are studied using the distributed parameter model. A new method to enhance the immunity to magnetic crosstalk is proposed. The experimental results show that magnetic crosstalk changes periodically with the azimuth angle and decreases as the distance between the conductors increases. When the sensing coil is placed at the optimal azimuth angle, the ratio error from magnetic crosstalk decreases from -0.32% to -0.02%, demonstrating the effectiveness of the proposed method. PMID:26836653
OPTIMAL SHRINKAGE ESTIMATION OF MEAN PARAMETERS IN FAMILY OF DISTRIBUTIONS WITH QUADRATIC VARIANCE
Xie, Xianchao; Kou, S. C.; Brown, Lawrence
2015-01-01
This paper discusses the simultaneous inference of mean parameters in a family of distributions with quadratic variance function. We first introduce a class of semi-parametric/parametric shrinkage estimators and establish their asymptotic optimality properties. Two specific cases, the location-scale family and the natural exponential family with quadratic variance function, are then studied in detail. We conduct a comprehensive simulation study to compare the performance of the proposed methods with existing shrinkage estimators. We also apply the method to real data and obtain encouraging results. PMID:27041778
NASA Astrophysics Data System (ADS)
Yan, Koon-Kiu; Axelsen, Jacob; Maslov, Sergei
2006-03-01
The evolution of the full repertoire of proteins encoded in a given genome is driven by gene duplications, deletions and modifications of amino-acid sequences of already existing proteins. The information about relative rates and other intrinsic parameters of these three basic processes is contained in the distribution of sequence identities of pairs of paralogous proteins. We introduced a simple mathematical framework that allows one to extract some of this hidden information. It was then applied to the proteome-wide set of paralogous proteins in H. pylori, E. coli, S. cerevisiae, C. elegans, D. melanogaster and H. sapiens. We estimated the stationary per-gene deletion and duplication rates, the distribution of amino-acid substitution rate of these organisms. The validity of our mathematical framework was further confirmed by numerical simulations of a simple evolutionary model of a fixed-size proteome.
NASA Technical Reports Server (NTRS)
Armand, J. P.
1972-01-01
An extension of classical methods of optimal control theory for systems described by ordinary differential equations to distributed-parameter systems described by partial differential equations is presented. An application is given involving the minimum-mass design of a simply-supported shear plate with a fixed fundamental frequency of vibration. An optimal plate thickness distribution in analytical form is found. The case of a minimum-mass design of an elastic sandwich plate whose fundamental frequency of free vibration is fixed. Under the most general conditions, the optimization problem reduces to the solution of two simultaneous partial differential equations involving the optimal thickness distribution and the modal displacement. One equation is the uniform energy distribution expression which was found by Ashley and McIntosh for the optimal design of one-dimensional structures with frequency constraints, and by Prager and Taylor for various design criteria in one and two dimensions. The second equation requires dynamic equilibrium at the preassigned vibration frequency.
NASA Astrophysics Data System (ADS)
Becker, Thorsten W.; Conrad, Clinton P.; Buffett, Bruce; Müller, R. Dietmar
2009-02-01
Variations in Earth's rates of seafloor generation and recycling have far-reaching consequences for sea level, ocean chemistry, and climate. However, there is little agreement on the correct parameterization for the time-dependent evolution of plate motions. A strong constraint is given by seafloor age distributions, which are affected by variations in average spreading rate, ridge length, and the age distribution of seafloor being removed by subduction. Using a simplified evolution model, we explore which physical parameterizations of these quantities are compatible with broad trends in the area per seafloor age statistics for the present-day and back to 140 Ma from paleo-age reconstructions. We show that a probability of subduction based on plate buoyancy (slab-pull, or "sqrt(age)") and a time-varying spreading rate fits the observed age distributions as well as, or better than, a subduction probability consistent with an unvarying "triangular" age distribution and age-independent destruction of ocean floor. Instead, we interpret the present near-triangular distribution of ages as a snapshot of a transient state of the evolving oceanic plate system. Current seafloor ages still contain hints of a ˜ 60 Myr periodicity in seafloor production, and using paleoages, we find that a ˜ 250 Myr period variation is consistent with geologically-based reconstructions of production rate variations. These long-period variations also imply a decrease of oceanic heat flow by ˜ - 0.25%/Ma during the last 140 Ma, caused by a 25-50% decrease in the rate of seafloor production. Our study offers an improved understanding of the non-uniformitarian evolution of plate tectonics and the interplay between continental cycles and the self-organization of the oceanic plates.
Valero Juan, L F; Sáenz González, M C
1997-11-01
The maternal mortality evolution in Spain during the 1980-1992 period is reported. The influence of birth distribution according to maternal age is analyzed. The information was gathered from vital statistics published by Instituto Nacional de Estadística. The mortality rates have stabilized since 1985 (4.8 per 10(5) for 1992) associated with the increase in the proportion of births in women aged > or = 30 years (40.6% for 1992). Birth distributions according to maternal age account for 13.1% of the deaths observed. The predictions point to an increase in maternal mortality for the year 2000.
Uranium distribution and 'excessive' U-He ages in iron meteoritic troilite
NASA Technical Reports Server (NTRS)
Fisher, D. E.
1985-01-01
Fission tracking techniques were used to measure the uranium distribution in meteoritic troilite and graphite. The obtained fission tracking data showed a heterogeneous distribution of tracks with a significant portion of track density present in the form of uranium clusters at least 10 microns in size. The matrix containing the clusters was also heterogeneous in composition with U concentrations of about 0.2-4.7 ppb. U/He ages could not be estimated on the basis of the heterogeneous U distributions, so previously reported estimates of U/He ages in the presolar range are probably invalid.
A theory of the cancer age-specific incidence data based on extreme value distributions
NASA Astrophysics Data System (ADS)
Soto-Ortiz, Luis; Brody, James P.
2012-03-01
The incidence of cancers varies with age, if normalized this is called the age-specific incidence. A mathematical model that describes this variation should provide a better understanding of how cancers develop. We suggest that the age-specific incidence should follow an extreme value distribution, based on three widely accepted assumptions: (1) a tumor develops from a single cell, (2) many potential tumor progenitor cells exist in a tissue, and (3) cancer is diagnosed when the first of these many potential tumor cells develops into a tumor. We tested this by comparing the predicted distribution to the age-specific incidence data for colon and prostate carcinomas collected by the Surveillance, Epidemiology and End Results network of 17 cancer registries. We found that colon carcinoma age-specific incidence data is consistent with an extreme value distribution, while prostate carcinomas age-specific incidence data generally follows the distribution. This model indicates that both colon and prostate carcinomas only occur in a subset of the population (22% for prostate and 13.5% for colon.) Because of their very general nature, extreme value distributions might be applicable to understanding other chronic human diseases.
Some bounds in classes of {open_quotes}aging{close_quotes} distributions
Kotlyar, V.Yu.
1995-03-01
Reliability of technical systems is closely linked with {open_quotes}aging{close_quotes} properties of the components. So-called monotone systems whose components have certain aging characteristics are of considerable importance in this field of research. Efficient bounds of reliability, mean time to failure, and other parameters can be obtained for such systems. The bounds in literature were obtained under the least restrictive assumptions on aging. In this paper, we generalize some results of literature to the case of even more general aging principles, specifically, when the system components are HNBUE, HNWUE, NBAFR, NWAFR in terms of their reliability properties. We start with a definition of these properties.
NASA Astrophysics Data System (ADS)
Colombini, Isabella; Fallaci, Mario; Chelazzi, Lorenzo
2005-11-01
A study on the spatial distribution of two tenebrionids and an isopod species was conducted at a small extent. Two species of the genus Phaleria were chosen because of their sympatric distribution and apparently similar adaptations to the beach environment. These scavenger species were studied in association to Tylos europaeus. Distributions, both perpendicular and parallel to the shoreline, were studied simultaneously with a grid of 20 × 20 pitfall traps arranged at a distance of 1 m from each other. Faunal samples were collected at two different hours of the night and core samples of sand were taken next to each pitfall trap for successive laboratory analysis. An index of dispersion was applied to test for aggregation of all species and of environmental parameters on the total, across- and long-shore. Kolmogorov-Smirnov two-sample test was used to compare the distributions between species. Regression analyse were applied to evaluate relationships between environmental parameters and species distributions. The study showed that the distribution of Phaleria species and T. europaeus was scale-dependent. The species and the values of the environmental parameters showed aggregated distributions both across- and long-shore. Aggregations of each Phaleria species differed according to their resting and foraging phases. For all species, sand moisture and salinity were the most important parameters explaining distribution. Granulometric parameters were correlated with the choice of the resting areas of both Phaleria species, whereas the spatial distribution of T. europaeus was correlated to the distribution of the organic matter.
Determination of the age distribution of sea ice from Lagrangian observations of ice motion
Kwok, R.; Cunningham, G.F.; Rothrock, D.A.; Stern, H.L.
1995-03-01
A procedure for monitoring the local age distribution of the Arctic sea ice cover is presented. The age distribution specifies the area covered by ice in different age classes. In the authors` approach, a regular array of grid points is defined initially on the first image of a long time series, and an ice tracker finds the positions of those points in all subsequent images of the series. These Lagrangian points mark the corners of a set of cells that move and deform with the ice cover. The area of each cell changes with each new image or time step. A positive change indicates that ice in a new age class was formed in the cell. A negative change is assumed to have ridged the youngest ice in the cell, reducing its area. The ice in each cell ages as it progresses through the time series. The area of multiyear ice in each cell is computed using an ice classification algorithm. Any area that is not accounted for by the young ice or multiyear ice is assigned to a category of older first-year ice. They thus have a fine age resolution in the young end of the age distribution, and coarse resolution for older ice. The age distribution of the young ice can be converted to a thickness distribution using a simple empirical relation between accumulated freezing-degree days and ice thickness, or using a more complicated thermodynamic model. They describe a general scheme for implementing this procedure for the Arctic Ocean from fall freeze-up until the onset of melt in the spring. The concept is illustrated with a time series of five ERS-1 SAR images spanning a period of 12 days. Such a scheme could be implemented with RADARSAT SAR imagery to provide basin-wide ice age and thickness information.
NASA Astrophysics Data System (ADS)
Tcherednichenko, I. A.; Bastidas, L. A.; Lansey, K.
2004-12-01
We use two very recently introduced in hydrology measures of performance: the Distributions Oriented (DO) approach and a set theory-based similarity metric - the Hausdorff Norm (HN) to evaluate the performance of two extensively used distributed rainfall-runoff models: Topmodel and PRMS. The distribution oriented approach considers the bivariate distribution of model outputs and observations and the corresponding marginal distributions. The Hausdorff norm allows for the inclusion, within the same framework or measure, both the spatial and temporal scales as a single multi-dimensional array. The performance evaluation is carried out over different time and spatial scales. The models are run over two nested catchments located in different climatic environments - one relatively wet, the Blue River in Oklahoma, and other semi-arid - the Sycamore Creek in Arizona. The levels and quality of input information are very dissimilar. To drive the models radar precipitation is used for the Blue River while the products generated at the University of Washington and gage measurements are used for Sycamore Creek. Both catchments have nested gages and the models are run to simulate 10 years of daily runoff at those points with different levels of discretization/resolution. Both measures: the DO and the HN, are used for parameter estimation using the multiple objective framework developed at the University of Arizona -that allows for the inclusion of trade-off uncertainties of the objective functions, and are compared against each other and against traditional scalar measures of performance as Nash Sutcliffe efficiency, bias, and general duration curves. In the Sycamore Creek a PRMS parameterization of the channel transmission losses is also considered for evaluation because of the important role played by those losses in the shape of the hydrographs.
NASA Astrophysics Data System (ADS)
Allende Prieto, C.; Fernández-Alvar, E.; Schlesinger, K. J.; Lee, Y. S.; Morrison, H. L.; Schneider, D. P.; Beers, T. C.; Bizyaev, D.; Ebelke, G.; Malanushenko, E.; Malanushenko, V.; Oravetz, D.; Pan, K.; Simmons, A.; Simmerer, J.; Sobeck, J.; Robin, A. C.
2014-08-01
Aims: We analyze a sample of tens of thousands of spectra of halo turnoff stars, obtained with the optical spectrographs of the Sloan Digital Sky Survey (SDSS), to characterize the stellar halo population "in situ" out to a distance of a few tens of kpc from the Sun. In this paper we describe the derivation of atmospheric parameters. We also derive the overall stellar metallicity distribution based on F-type stars observed as flux calibrators for the Baryonic Oscillations Spectroscopic Survey (BOSS). Methods: Our analysis is based on an automated method that determines the set of parameters of a model atmosphere that reproduces each observed spectrum best. We used an optimization algorithm and evaluate model fluxes by means of interpolation in a precomputed grid. In our analysis, we account for the spectrograph's varying resolution as a function of fiber and wavelength. Our results for early SDSS (pre-BOSS upgrade) data compare well with those from the SEGUE Stellar Parameter Pipeline (SSPP), except for stars with log g (cgs units) lower than 2.5. Results: An analysis of stars in the globular cluster M 13 reveals a dependence of the inferred metallicity on surface gravity for stars with log g < 2.5, confirming the systematics identified in the comparison with the SSPP. We find that our metallicity estimates are significantly more precise than the SSPP results. We also find excellent agreement with several independent analyses. We show that the SDSS color criteria for selecting F-type halo turnoff stars as flux calibrators efficiently excludes stars with high metallicities, but does not significantly distort the shape of the metallicity distribution at low metallicity. We obtain a halo metallicity distribution that is narrower and more asymmetric than in previous studies. The lowest gravity stars in our sample, at tens of kpc from the Sun, indicate a shift of the metallicity distribution to lower abundances, consistent with what is expected from a dual halo system
2013-01-01
Background Today industrialized countries face a burgeoning aged population. Thus, there is increasing attention on the functioning and disabilities of aged adults as potential determinants of autonomy and independent living. However, there are few representative findings on the prevalence and determinants of disability in aged persons in the German population. The objective of our study is to examine the frequency, distribution and determinants of functioning and disability in aged persons and to assess the contribution of diseases to the prevalence of disability. Methods Data originate from the MONICA/KORA study, a population-based epidemiological cohort. Survivors of the original cohorts who were 65 and older were examined by telephone interview in 2009. Disability was assessed with the Health Assessment Questionnaire Disability Index (HAQ-DI). Minimal disability was defined as HAQ-DI > 0. Logistic regression was used to adjust for potential confounders and additive regression to estimate the contribution of diseases to disability prevalence. Results We analyzed a total of 4117 persons (51.2% female) with a mean age of 73.6 years (SD = 6.1). Minimal disability was present in 44.7% of all participants. Adjusted for age and diseases, disability was positively associated with female sex, BMI, low income, marital status, physical inactivity and poor nutritional status, but not with smoking and education. Problems with joint functions and eye diseases contributed most to disability prevalence in all age groups. Conclusions In conclusion, this study could show that there are vulnerable subgroups of aged adults who should receive increased attention, specifically women, those with low income, those over 80, and persons with joint or eye diseases. Physical activity, obesity and malnutrition were identified as modifiable factors for future targeted interventions. PMID:23410010
Lee, Jae Hoon; Joshi, Amit; Sevick-Muraca, Eva M
2008-01-01
A variety of biomedical imaging techniques such as optical and fluorescence tomography, electrical impedance tomography, and ultrasound imaging can be cast as inverse problems, wherein image reconstruction involves the estimation of spatially distributed parameter(s) of the PDE system describing the physics of the imaging process. Finite element discretization of imaged domain with tetrahedral elements is a popular way of solving the forward and inverse imaging problems on complicated geometries. A dual-adaptive mesh-based approach wherein, one mesh is used for solving the forward imaging problem and the other mesh used for iteratively estimating the unknown distributed parameter, can result in high resolution image reconstruction at minimum computation effort, if both the meshes are allowed to adapt independently. Till date, no efficient method has been reported to identify and resolve intersection between tetrahedrons in independently refined or coarsened dual meshes. Herein, we report a fast and robust algorithm to identify and resolve intersection of tetrahedrons within nested dual meshes generated by 8-similar subtetrahedron subdivision scheme. The algorithm exploits finite element weight functions and gives rise to a set of weight functions on each vertex of disjoint tetrahedron pieces that completely cover up the intersection region of two tetrahedrons. The procedure enables fully adaptive tetrahedral finite elements by supporting independent refinement and coarsening of each individual mesh while preserving fast identification and resolution of intersection. The computational efficiency of the algorithm is demonstrated by diffuse photon density wave solutions obtained from a single- and a dual-mesh, and by reconstructing a fluorescent inclusion in simulated phantom from boundary frequency domain fluorescence measurements.
NASA Astrophysics Data System (ADS)
Lee, T. S.; Yoon, S.; Jeong, C.
2012-12-01
The primary purpose of frequency analysis in hydrology is to estimate the magnitude of an event with a given frequency of occurrence. The precision of frequency analysis depends on the selection of an appropriate probability distribution model (PDM) and parameter estimation techniques. A number of PDMs have been developed to describe the probability distribution of the hydrological variables. For each of the developed PDMs, estimated parameters are provided based on alternative estimation techniques, such as the method of moments (MOM), probability weighted moments (PWM), linear function of ranked observations (L-moments), and maximum likelihood (ML). Generally, the results using ML are more reliable than the other methods. However, the ML technique is more laborious than the other methods because an iterative numerical solution, such as the Newton-Raphson method, must be used for the parameter estimation of PDMs. In the meantime, meta-heuristic approaches have been developed to solve various engineering optimization problems (e.g., linear and stochastic, dynamic, nonlinear). These approaches include genetic algorithms, ant colony optimization, simulated annealing, tabu searches, and evolutionary computation methods. Meta-heuristic approaches use a stochastic random search instead of a gradient search so that intricate derivative information is unnecessary. Therefore, the meta-heuristic approaches have been shown to be a useful strategy to solve optimization problems in hydrology. A number of studies focus on using meta-heuristic approaches for estimation of hydrological variables with parameter estimation of PDMs. Applied meta-heuristic approaches offer reliable solutions but use more computation time than derivative-based methods. Therefore, the purpose of this study is to enhance the meta-heuristic approach for the parameter estimation of PDMs by using a recently developed algorithm known as a harmony search (HS). The performance of the HS is compared to the
NASA Astrophysics Data System (ADS)
Carvalho, C. Sofia; Basilakos, Spyros
2016-08-01
We use a kinematic parametrisation of the luminosity distance to measure the angular distribution on the sky of time derivatives of the scale factor, in particular the Hubble parameter H0, the deceleration parameter q0, and the jerk parameter j0. We apply a recently published method to complement probing the inhomogeneity of the large-scale structure by means of the inhomogeneity in the cosmic expansion. This parametrisation is independent of the cosmological equation of state, which renders it adequate to test interpretations of the cosmic acceleration alternative to the cosmological constant. For the same analytical toy model of an inhomogeneous ensemble of homogenous pixels, we derive the backreaction term in j0 due to the fluctuations of { H0,q0 } and measure it to be of order 10-2 times the corresponding average over the pixels in the absence of backreaction. In agreement with that computed using a ΛCDM parametrisation of the luminosity distance, the backreaction effect on q0 remains below the detection threshold. Although the backreaction effect on j0 is about ten times that on q0, it is also below the detection threshold. Hence backreaction remains unobservable both in q0 and in j0.
The identification of a distributed parameter model for a flexible structure
NASA Technical Reports Server (NTRS)
Banks, H. T.; Gates, S. S.; Rosen, I. G.; Wang, Y.
1986-01-01
A computational method is developed for the estimation of parameters in a distributed model for a flexible structure. The structure we consider (part of the RPL experiment) consists of a cantilevered beam with a thruster and linear accelerometer at the free end. The thruster is fed by a pressurized hose whose horizontal motion effects the transverse vibration of the beam. The Euler-Bernoulli theory is used to model the vibration of the beam and treat the hose-thruster assembly as a lumped or point mass-dashpot-spring system at the tip. Using measurements of linear acceleration at the tip, it is estimated that the parameters (mass, stiffness, damping) and a Voight-Kelvin viscoelastic structural damping parameter for the beam using a least squares fit to the data. Spline based approximations to the hybrid (coupled ordinary and partial differential equations) system are considered; theoretical convergence results and numerical studies with both simulation and actual experimental data obtained from the structure are presented and discussed.
Spatial distribution of the plasma parameters in the RF negative ion source prototype for fusion
Lishev, S.; Schiesko, L.; Wünderlich, D.; Fantz, U.
2015-04-08
A numerical model, based on the fluid plasma theory, has been used for description of the spatial distribution of the plasma parameters (electron density and temperature, plasma potential as well as densities of the three types of positive hydrogen ions) in the IPP prototype RF negative hydrogen ion source. The model covers the driver and the expansion plasma region of the source with their actual size and accounts for the presence of the magnetic filter field with its actual value and location as well as for the bias potential applied to the plasma grid. The obtained results show that without a magnetic filter the two 2D geometries considered, respectively, with an axial symmetry and a planar one, represent accurately the complex 3D structure of the source. The 2D model with a planar symmetry (where the E×B and diamagnetic drifts could be involved in the description) has been used for analysis of the influence, via the charged-particle and electron-energy fluxes, of the magnetic filter and of the bias potential on the spatial structure of the plasma parameters in the source. Benchmarking of results from the code to experimental data shows that the model reproduces the general trend in the axial behavior of the plasma parameters in the source.
Spatial distribution of the plasma parameters in the RF negative ion source prototype for fusion
NASA Astrophysics Data System (ADS)
Lishev, S.; Schiesko, L.; Wünderlich, D.; Fantz, U.
2015-04-01
A numerical model, based on the fluid plasma theory, has been used for description of the spatial distribution of the plasma parameters (electron density and temperature, plasma potential as well as densities of the three types of positive hydrogen ions) in the IPP prototype RF negative hydrogen ion source. The model covers the driver and the expansion plasma region of the source with their actual size and accounts for the presence of the magnetic filter field with its actual value and location as well as for the bias potential applied to the plasma grid. The obtained results show that without a magnetic filter the two 2D geometries considered, respectively, with an axial symmetry and a planar one, represent accurately the complex 3D structure of the source. The 2D model with a planar symmetry (where the E×B and diamagnetic drifts could be involved in the description) has been used for analysis of the influence, via the charged-particle and electron-energy fluxes, of the magnetic filter and of the bias potential on the spatial structure of the plasma parameters in the source. Benchmarking of results from the code to experimental data shows that the model reproduces the general trend in the axial behavior of the plasma parameters in the source.
Water quality parameter estimation in a distribution system under dynamic state.
Munavalli, G R; Mohan Kumar, M S
2005-11-01
Chlorine maintenance in distribution systems is an issue for water suppliers. The complex pipe geometry in distribution systems, the dynamic flow conditions experienced within them, and the varied nature of chlorine's reactivity make it difficult to predict chlorine levels throughout a water system. Computer-based mathematical models of water quality transport and fate within distribution systems offer a promising tool for predicting chlorine in a cost-effective manner. Nevertheless, the use of water quality models can only be effective and reliable when both hydraulics and the mechanisms of chlorine dissipation within the water system are properly defined. Bulk water decay can be measured experimentally. However, wall reaction rates are more complex to determine and must be deduced from field measurement by comparison with simulation results. The simulation-optimization model presented in this paper provides an effective tool to simplify the chlorine decay model calibration process that is often tedious. The optimization tool is based on the weighted-least-squares method solved by Gauss-Newton technique. Application of the model onto a real-life system shows that quantity, quality and location of measurement nodes play an important role in estimation of parameters.
Pleil, Joachim D; Sobus, Jon R; Stiegel, Matthew A; Hu, Di; Oliver, Karen D; Olenick, Cassandra; Strynar, Mark; Clark, Mary; Madden, Michael C; Funk, William E
2014-01-01
The progression of science is driven by the accumulation of knowledge and builds upon published work of others. Another important feature is to place current results into the context of previous observations. The published literature, however, often does not provide sufficient direct information for the reader to interpret the results beyond the scope of that particular article. Authors tend to provide only summary statistics in various forms, such as means and standard deviations, median and range, quartiles, 95% confidence intervals, and so on, rather than providing measurement data. Second, essentially all environmental and biomonitoring measurements have an underlying lognormal distribution, so certain published statistical characterizations may be inappropriate for comparisons. The aim of this study was to review and develop direct conversions of different descriptions of data into a standard format comprised of the geometric mean (GM) and the geometric standard deviation (GSD) and then demonstrate how, under the assumption of lognormal distribution, these parameters are used to answer questions of confidence intervals, exceedance levels, and statistical differences among distributions. A wide variety of real-world measurement data sets was reviewed, and it was demonstrated that these data sets are indeed of lognormal character, thus making them amenable to these methods. Potential errors incurred from making retrospective estimates from disparate summary statistics are described. In addition to providing tools to interpret "other people's data," this review should also be seen as a cautionary tale for publishing one's own data to make it as useful as possible for other researchers.
Kheifets, A. S.; Ivanov, I. A.; Bray, Igor
2007-08-15
We present convergent-close-coupling (CCC) calculations of the angular anisotropy parameters {beta}{sub 2},{beta}{sub 4} and the recoil ion momentum distribution d{sigma}/dp in two-photon double ionization (TPDI) of helium. In a stark contrast to single-photon double ionization (SPDI), where the {beta}{sub 2} parameter varies widely changing the angular distribution from isotropic to nearly dipole for slow and fast photoelectrons, respectively, the {beta} parameters for TPDI show very little change. The angular distribution of the recoil ion is fairly isotropic in TPDI as opposed to a strong alignment with the polarization of light in SPDI.
NASA Astrophysics Data System (ADS)
Sanford, W. E.
2015-12-01
Age distributions of base flow to streams are important to estimate for predicting the timing of water-quality responses to changes in distributed inputs of nutrients or pollutants at the land surface. Simple models of shallow aquifers will predict exponential age distributions, but more realistic 3-D stream-aquifer geometries will cause deviations from an exponential curve. In addition, in fractured rock terrains the dual nature of the effective and total porosity of the system complicates the age distribution further. In this study shallow groundwater flow and advective transport were simulated in two regions in the Eastern United States—the Delmarva Peninsula and the upper Potomac River basin. The former is underlain by layers of unconsolidated sediment, while the latter consists of folded and fractured sedimentary rocks. Transport of groundwater to streams was simulated using the USGS code MODPATH within 175 and 275 watersheds, respectively. For the fractured rock terrain, calculations were also performed along flow pathlines to account for exchange between mobile and immobile flow zones. Porosities at both sites were calibrated using environmental tracer data (3H, 3He, CFCs and SF6) in wells and springs, and with a 30-year tritium record from the Potomac River. Carbonate and siliciclastic rocks were calibrated to have mobile porosity values of one and six percent, and immobile porosity values of 18 and 12 percent, respectively. The age distributions were fitted to Weibull functions. Whereas an exponential function has one parameter that controls the median age of the distribution, a Weibull function has an extra parameter that controls the slope of the curve. A weighted Weibull function was also developed that potentially allows for four parameters, two that control the median age and two that control the slope, one of each weighted toward early or late arrival times. For both systems the two-parameter Weibull function nearly always produced a substantially
Xu Huijun; Gordon, J. James; Siebers, Jeffrey V.
2011-02-15
Purpose: A dosimetric margin (DM) is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution (DMD) is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter- or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk (OAR) dose metric D{sub v} exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structures meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Methods: Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume (CTV-to-PTV) margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals {omega} (e.g., {omega}=1 deg., 2 deg., 5 deg., 10 deg., 20 deg.). Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment {omega}{sub eff}. In each direction, the DM was calculated by moving the structure in radial steps of size {delta}(=0.1,0.2,0.5,1 mm) until the specified isodose was crossed. Coverage estimation accuracy {Delta}Q was quantified as a function of the sampling parameters {omega} or
NASA Astrophysics Data System (ADS)
Müller, Markus; Meztler, Holger; Glatt, Anna; Sierra, Carlos
2016-04-01
We present theoretical methods to compute dynamic residence and transit time distributions for non-autonomous systems of pools governed by coupled nonlinear differential equations. Although transit time and age distributions have been used to describe reservoir models for a long time, a closer look to their assumptions reveals two major restrictions of generality in previous studies. First, the systems are assumed to be in equilibrium; and second, the equations under consideration are assumed to be linear. While both these assumptions greatly ease the computation and interpretation of transit time and age distributions they are not applicable to a wide range of problems. Moreover, the transfer of previous results learned from linear systems in steady state to the more complex nonlinear non-autonomous systems that do not even need to have equilibria, can be dangerously misleading. Fortunately the topic of time dependent age and transit time distributions has received some attention recently in hydrology, we aim to compute these distributions for systems of multiple reservoirs. We will discuss how storage selection functions can augment the information represented in an ODE system describing a system of reservoirs. We will present analytical and numerical algorithms and a Monte Carlo simulator to compute solutions for system transit time and age distributions for system-wide storage selection functions including the most simple, but important case of well mixed pools.
Inverse planning in the age of digital LINACs: station parameter optimized radiation therapy (SPORT)
NASA Astrophysics Data System (ADS)
Xing, Lei; Li, Ruijiang
2014-03-01
The last few years have seen a number of technical and clinical advances which give rise to a need for innovations in dose optimization and delivery strategies. Technically, a new generation of digital linac has become available which offers features such as programmable motion between station parameters and high dose-rate Flattening Filter Free (FFF) beams. Current inverse planning methods are designed for traditional machines and cannot accommodate these features of new generation linacs without compromising either dose conformality and/or delivery efficiency. Furthermore, SBRT is becoming increasingly important, which elevates the need for more efficient delivery, improved dose distribution. Here we will give an overview of our recent work in SPORT designed to harness the digital linacs and highlight the essential components of SPORT. We will summarize the pros and cons of traditional beamlet-based optimization (BBO) and direct aperture optimization (DAO) and introduce a new type of algorithm, compressed sensing (CS)-based inverse planning, that is capable of automatically removing the redundant segments during optimization and providing a plan with high deliverability in the presence of a large number of station control points (potentially non-coplanar, non-isocentric, and even multi-isocenters). We show that CS-approach takes the interplay between planning and delivery into account and allows us to balance the dose optimality and delivery efficiency in a controlled way and, providing a viable framework to address various unmet demands of the new generation linacs. A few specific implementation strategies of SPORT in the forms of fixed-gantry and rotational arc delivery are also presented.
NASA Astrophysics Data System (ADS)
Reynolds Puga, Jose Eduardo; Halldin, Sven; Xu, Chong-Yu; Seibert, Jan
2016-04-01
Flood forecasting at sub-daily time scales are commonly required in regions where sub-daily observational data are not available. This has led to approaches to estimate model parameters at sub-daily time scales from data with a lower time resolution. Reynolds et al. (2015) show that parameters inferred at one time scale (e.g., daily) may be used directly for runoff simulations at other time scales (e.g., 1 h) when the modelling time step is the same and sufficiently small during calibration and simulation periods. Their approach produced parameter distributions at daily and sub-daily time scales that were similar and relatively constant across the time scales. The transfer of parameter values across time scales resulted in small model-performance decrease as opposed to when the parameter sets inferred at their respective time scale were used. This decrease in performance may be attributed to the degree of information lost, in terms of the physical processes occurring at short time scales, when the rainfall-runoff data used during the parameter-inference phase become coarser. It is not yet fully understood how the aggregation (or disaggregation) of the rainfall-runoff data affects parameter inference. In this study we analyse the impacts of the temporal distribution of rainfall for inferring model parameters at a coarse time scale and their effects in model performance when they are used at finer time scales, where data may not be available for calibration. The motivation is to improve runoff predictions and model performance at sub-daily time scales when parameters inferred at the daily scale are used for simulating at these scales. First, we calibrated the HBV-light conceptual hydrological model at the daily scale, but modelled discharge internally in 1-h time steps using 3 disaggregation procedures of the rainfall data. This was done in an attempt to maximise the information content of the input data used for calibration at the daily scale. One disaggregation
Model Predictive Optimal Control of a Time-Delay Distributed-Parameter Systems
NASA Technical Reports Server (NTRS)
Nguyen, Nhan
2006-01-01
This paper presents an optimal control method for a class of distributed-parameter systems governed by first order, quasilinear hyperbolic partial differential equations that arise in many physical systems. Such systems are characterized by time delays since information is transported from one state to another by wave propagation. A general closed-loop hyperbolic transport model is controlled by a boundary control embedded in a periodic boundary condition. The boundary control is subject to a nonlinear differential equation constraint that models actuator dynamics of the system. The hyperbolic equation is thus coupled with the ordinary differential equation via the boundary condition. Optimality of this coupled system is investigated using variational principles to seek an adjoint formulation of the optimal control problem. The results are then applied to implement a model predictive control design for a wind tunnel to eliminate a transport delay effect that causes a poor Mach number regulation.
Study on spatial distribution of plasma parameters in a magnetized inductively coupled plasma
Cheong, Hee-Woon; Lee, Woohyun; Kim, Ji-Won; Whang, Ki-Woong; Kim, Hyuk; Park, Wanjae
2015-07-15
Spatial distributions of various plasma parameters such as plasma density, electron temperature, and radical density in an inductively coupled plasma (ICP) and a magnetized inductively coupled plasma (M-ICP) were investigated and compared. Electron temperature in between the rf window and the substrate holder of M-ICP was higher than that of ICP, whereas the one just above the substrate holder of M-ICP was similar to that of ICP when a weak (<8 G) magnetic field was employed. As a result, radical densities in M-ICP were higher than those in ICP and the etch rate of oxide in M-ICP was faster than that in ICP without severe electron charging in 90 nm high aspect ratio contact hole etch.
Bragt, D.D.B. van; Rizwan-uddin; Hagen, T.H.J.J. van der
2000-02-15
Bifurcation analyses of the impact of the void distribution parameter C{sub 0} and the axial power profile on the stability of boiling water reactors (BWRs) are reported. Bifurcation characteristics of heated channels (without nuclear feedback) appear to be very sensitive to the axial power profile. A turning point bifurcation was detected for a (symmetrically) peaked axial power profile. This kind of bifurcation does not occur for a uniformly heated channel.Both supercritical and subcritical Hopf bifurcations were encountered in a (nuclear-coupled) reactor system, depending on the strength of the void reactivity feedback. Subcritical bifurcations become less likely to occur as C{sub 0} is significantly larger than unity. In BWRs with a strong nuclear feedback, the oscillation amplitude of limit cycles caused by a supercritical bifurcation is very sensitive to both C{sub 0} and the axial power profile.
NASA Astrophysics Data System (ADS)
Ansari, A. A.; Sartale, S. D.
2016-08-01
A simple method to grow uniform sized Ag nanoparticles with narrow size distribution on flat support (glass and Si substrates) via spin coating of Ag+ ions (AgNO3) solution followed by thermal reduction in H2 is presented. These grown nanoparticles can be used as model catalytic system to study size dependent oxygen reduction reaction (ORR) activity. Ag nanoparticles formation was confirmed by local surface plasmon resonance and x-ray photoelectron spectroscopy measurements. Influences of process parameters (revolution per minute (rpm), ramp and salt concentration) on grown Ag nanoparticles size, density and size uniformity are studied. With increase in rpm and ramp the size decreases and the particle number density increases, whereas the size dispersion improves. The catalytic activity of the grown Ag particles for ORR is studied and it is found that the catalytic performance is dependent on the size as well as the number density of the grown Ag nanoparticles.
Distributed Parameter Analysis of Pressure and Flow Disturbances in Rocket Propellant Feed Systems
NASA Technical Reports Server (NTRS)
Dorsch, Robert G.; Wood, Don J.; Lightner, Charlene
1966-01-01
A digital distributed parameter model for computing the dynamic response of propellant feed systems is formulated. The analytical approach used is an application of the wave-plan method of analyzing unsteady flow. Nonlinear effects are included. The model takes into account locally high compliances at the pump inlet and at the injector dome region. Examples of the calculated transient and steady-state periodic responses of a simple hypothetical propellant feed system to several types of disturbances are presented. Included are flow disturbances originating from longitudinal structural motion, gimbaling, throttling, and combustion-chamber coupling. The analytical method can be employed for analyzing developmental hardware and offers a flexible tool for the calculation of unsteady flow in these systems.
NASA Technical Reports Server (NTRS)
Bernstein, Dennis S.; Rosen, I. G.
1988-01-01
In controlling distributed parameter systems it is often desirable to obtain low-order, finite-dimensional controllers in order to minimize real-time computational requirements. Standard approaches to this problem employ model/controller reduction techniques in conjunction with LQG theory. In this paper we consider the finite-dimensional approximation of the infinite-dimensional Bernstein/Hyland optimal projection theory. This approach yields fixed-finite-order controllers which are optimal with respect to high-order, approximating, finite-dimensional plant models. The technique is illustrated by computing a sequence of first-order controllers for one-dimensional, single-input/single-output, parabolic (heat/diffusion) and hereditary systems using spline-based, Ritz-Galerkin, finite element approximation. Numerical studies indicate convergence of the feedback gains with less than 2 percent performance degradation over full-order LQG controllers for the parabolic system and 10 percent degradation for the hereditary system.
Sanchez, I.; Martin, F. )
1992-04-01
We report theoretical calculations for the {beta}{sub 2{ital p}}-asymmetry parameter in the photoionization of He(1{ital s}{sup 2}) above the {ital N}=2 ionization threshold. We use an extension of a method recently proposed (I. Sanchez and F. Martin, Phys. Rev. A 44, 7318 (1991)) that makes use of a Feshbach partitioning of the final-state wave function and an {ital L}{sup 2} representation of the coupled continuum states. Partial differential cross sections at emission angles 0{degree} and 90{degree} are also provided. Our results are in good agreement with the experimental data, thus showing the accuracy of the present method to study electron angular-distribution properties.
Implementing lifetime performance index of products with two-parameter exponential distribution
NASA Astrophysics Data System (ADS)
Lee, Hsiu-Mei; Wu, Jong-Wuu; Lei, Chia-Ling; Hung, Wen-Liang
2011-08-01
The manufacturing industry has prioritised enhancing the quality, lifetime and conforming rate of products. Process capability indices (PCIs) are used to measure process potential and performance. The process capability is evaluated with product survival time and a longer lifetime implies a better process capability and a higher reliability. In order to save experimental time and cost, a censored sample arises in practice. In the case of product possessing a two-parameter exponential distribution, this study constructs a uniformly minimum variance unbiased estimator (UMVUE) of the lifetime performance index based on the type II right-censored sample. Then the UMVUE of the lifetime performance index is utilised to develop the new hypothesis testing procedure in the condition of known lower specification limit. Finally, two practical examples are illustrated to employ the testing procedure to determine whether the product is reliable.
NASA Technical Reports Server (NTRS)
Balas, M. J.
1985-01-01
Distributed Parameter Systems (DPS), such as systems described by partial differential equations, require infinite-dimensional state space descriptions to correctly model their dynamical behavior. However, any adaptive control algorithm must be finite-dimensional in order to be implemented via on-line digital computers. Finite-dimensional adaptive control of linear DPS requires stability analysis of nonlinear, time-varying, infinite-dimensional systems. The structure of nonadaptive finite-dimensional control of linear DPS is summarized as it relates to the existence of limiting systems for adaptive control. Two candidate schemes for finite-dimensional adaptive control of DPS are described and critical issues in infinite-dimensional stability analysis are discussed, in particular, the invariance principle, center manifold theory, and relationships between input-output and internal stability.
NASA Technical Reports Server (NTRS)
Johnson, C. R., Jr.; Lawrence, D. A.
1981-01-01
The reduced order model problem in distributed parameter systems adaptive identification and control is investigated. A comprehensive examination of real-time centralized adaptive control options for flexible spacecraft is provided.
The vertical distribution of physical parameters in the Gulf of Riga for future climate projections.
NASA Astrophysics Data System (ADS)
Valainis, Aigars; Sennikovs, Juris
2010-05-01
Our goal was to investigate the vertical distribution of physical parameters (temperature, salinity) in the Gulf of Riga for the contemporay climate and for future climate projections. The Gulf of Riga is a semi-enclosed subbasin of the Baltic Sea between Latvia and Estonia. The area of the Gulf of Riga is about 18,000 sq. km. The maximum depth is 67 m. The island of Saaremaa partially separates it from the rest of the Baltic Sea. The main connection of the Gulf with the Baltic Proper is the Irbe Strait allowing limited exchanges with Baltic see. The Gulf of Riga was modelled with 1D model. Calculations were made for 55 m deep water column, taking into account hypsographic curve. The General Ocean Turbulence Model (GOTM) was used. Second order dynamic k-e equation with parameterization from Cheng (2002) was used for turbulence description. The result sensitivity was evaluated regarding models choice. Data from European Centre for Medium-Range Weather Forecasts (ECMWF) where used for calibration and verification period. Data included ECMWF ERA 40 for time period 1957-2002, and ECMWF ERA Interim for 1989-2009. Regional climate models (RCM) and scenarios for future climate change were obtained from Prediction of Regional scenarios and Uncertainties for Defining European Climate change risks and Effects (PRUDENCE) project. Time period for future physical parameter vertical distribution simulation was 2071-2100. We applied the bias correction (via histogram equalisation) of RCM data. We employed the setup of hydrological models to generate the contemporary and future river run-off data series Our results conclude that in future the Gulf won't freeze over. In summer surface temperature will increase at least by 2 degrees Celsius. Vertical stratification will begin a month earlier - as a consequence the time period of full mixing will be shorter.
Parameter identification of a distributed runoff model by the optimization software Colleo
NASA Astrophysics Data System (ADS)
Matsumoto, Kazuhiro; Miyamoto, Mamoru; Yamakage, Yuzuru; Tsuda, Morimasa; Anai, Hirokazu; Iwami, Yoichi
2015-04-01
The introduction of Colleo (Collection of Optimization software) is presented and case studies of parameter identification for a distributed runoff model are illustrated. In order to calculate discharge of rivers accurately, a distributed runoff model becomes widely used to take into account various land usage, soil-type and rainfall distribution. Feasibility study of parameter optimization is desired to be done in two steps. The first step is to survey which optimization algorithms are suitable for the problems of interests. The second step is to investigate the performance of the specific optimization algorithm. Most of the previous studies seem to focus on the second step. This study will focus on the first step and complement the previous studies. Many optimization algorithms have been proposed in the computational science field and a large number of optimization software have been developed and opened to the public with practically applicable performance and quality. It is well known that it is important to use suitable algorithms for the problems to obtain good optimization results efficiently. In order to achieve algorithm comparison readily, optimization software is needed with which performance of many algorithms can be compared and can be connected to various simulation software. Colleo is developed to satisfy such needs. Colleo provides a unified user interface to several optimization software such as pyOpt, NLopt, inspyred and R and helps investigate the suitability of optimization algorithms. 74 different implementations of optimization algorithms, Nelder-Mead, Particle Swarm Optimization and Genetic Algorithm, are available with Colleo. The effectiveness of Colleo was demonstrated with the cases of flood events of the Gokase River basin in Japan (1820km2). From 2002 to 2010, there were 15 flood events, in which the discharge exceeded 1000m3/s. The discharge was calculated with the PWRI distributed hydrological model developed by ICHARM. The target
A distributed fault-detection and diagnosis system using on-line parameter estimation
NASA Technical Reports Server (NTRS)
Guo, T.-H.; Merrill, W.; Duyar, A.
1991-01-01
The development of a model-based fault-detection and diagnosis system (FDD) is reviewed. The system can be used as an integral part of an intelligent control system. It determines the faults of a system from comparison of the measurements of the system with a priori information represented by the model of the system. The method of modeling a complex system is described and a description of diagnosis models which include process faults is presented. There are three distinct classes of fault modes covered by the system performance model equation: actuator faults, sensor faults, and performance degradation. A system equation for a complete model that describes all three classes of faults is given. The strategy for detecting the fault and estimating the fault parameters using a distributed on-line parameter identification scheme is presented. A two-step approach is proposed. The first step is composed of a group of hypothesis testing modules, (HTM) in parallel processing to test each class of faults. The second step is the fault diagnosis module which checks all the information obtained from the HTM level, isolates the fault, and determines its magnitude. The proposed FDD system was demonstrated by applying it to detect actuator and sensor faults added to a simulation of the Space Shuttle Main Engine. The simulation results show that the proposed FDD system can adequately detect the faults and estimate their magnitudes.
NASA Astrophysics Data System (ADS)
Li, H. T.; Yang, Z.; Zu, J.; Qin, W. Y.
2016-08-01
This paper presents the modeling and parametric analysis of the recently proposed nonlinear compressive-mode energy harvester (HC-PEH) under harmonic excitation. Both theoretical and experimental investigations are performed in this study over a range of excitation frequencies. Specially, a distributed parameter electro-elastic model is analytically developed by means of the energy-based method and the extended Hamilton's principle. An analytical formulation of bending and stretching forces are derived to gain insight on the source of nonlinearity. Furthermore, the analytical model is validated against with experimental data and a good agreement is achieved. Both numerical simulations and experiment illustrate that the harvester exhibits a hardening nonlinearity and hence a broad frequency bandwidth, multiple coexisting solutions and a large-amplitude voltage response. Using the derived model, a parametric study is carried out to examine the effect of various parameters on the harvester voltage response. It is also shown from parametric analysis that the harvester's performance can be further improved by selecting the proper length of elastic beams, proof mass and reducing the mechanical damping.
NASA Astrophysics Data System (ADS)
Tindale, E.; Chapman, S. C.
2016-06-01
We use 20 years of Wind solar wind observations to investigate the solar cycle variation of the solar wind driving of the magnetosphere. For the first time, we use generalized quantile-quantile plots to compare the statistical distribution of four commonly used solar wind coupling parameters, Poynting flux, B2, the ɛ parameter, and vB, between the maxima and minima of solar cycles 23 and 24. We find the distribution is multicomponent and has the same functional form at all solar cycle phases; the change in distribution is captured by a simple transformation of variables for each component. The ɛ parameter is less sensitive than its constituent variables to changes in the distribution of extreme values between successive solar maxima. The quiet minimum of cycle 23 manifests only in lower extreme values, while cycle 24 was less active across the full distribution range.
NASA Astrophysics Data System (ADS)
Rodriguez, L.; Masías-Meza, J. J.; Dasso, S.; Démoulin, P.; Zhukov, A. N.; Gulisano, A. M.; Mierla, M.; Kilpua, E.; West, M.; Lacatus, D.; Paraschiv, A.; Janvier, M.
2016-07-01
Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs). They are important because of their simple internal magnetic field configuration, which resembles a magnetic flux rope, and because they represent one of the most geoeffective types of solar transients. In this study, we analyze their internal structure using a superposed epoch method on 63 events observed at L1 by the Advance Composition Explorer (ACE), between 1998 and 2006. In this way, we obtain an average profile for each plasma and magnetic field parameter at each point of the cloud. Furthermore, we take a fixed time-window upstream and downstream from the MC to also sample the regions preceding the cloud and the wake trailing it. We then perform a detailed analysis of the internal characteristics of the clouds and their surrounding solar wind environments. We find that the parameters studied are compatible with log-normal distribution functions. The plasma β and the level of fluctuations in the magnetic field vector are the best parameters to define the boundaries of MCs. We find that one third of the events shows a peak in plasma density close to the trailing edge of the flux ropes. We provide several possible explanations for this result and investigate if the density peak is of a solar origin (e.g. erupting prominence material) or formed during the magnetic cloud travel from the Sun to 1 AU. The most plausible explanation is the compression due to a fast overtaking flow, coming from a coronal hole located to the east of the solar source region of the magnetic cloud.
NASA Astrophysics Data System (ADS)
Haimovich, Alexander M.; Peckham, C. D.; Teti, Joseph G., Jr.
1994-06-01
It is well known that targets moving along track within a Synthetic Aperture Radar (SAR) field of view are imaged as defocused objects. The SAR stripmap mode is tuned to stationary ground targets and the mismatch between the SAR processing parameters and the target motion parameters causes the energy to spill over to adjacent image pixels, thus not only hindering target feature extraction, but also reducing the probability of detection. The problem can be remedied by generating the image using a filter matched to the actual target motion parameters, effectively focusing the SAR image on the target. For a fixed rate of motion the target velocity can be estimated from the slope of the Doppler frequency characteristic. The processing is carried out on the range compressed data but before azimuth compression. The problem is similar to the classical problem of estimating the instantaneous frequency of a linear FM signal (chirp). This paper investigates the application of three different time-frequency analysis techniques to estimate the instantaneous Doppler frequency of range compressed SAR data. In particular, we compare the Wigner-Ville distribution, the Gabor expansion and the Short-Time Fourier transform with respect to their performance in noisy SAR data. Criteria are suggested to quantify the performance of each method in the joint time- frequency domain. It is shown that these methods exhibit sharp signal-to-noise threshold effects, i.e., a certain SNR below which the accuracy of the velocity estimation deteriorates rapidly. It is also shown that the methods differ with respect to their representation of the SAR data.
NASA Astrophysics Data System (ADS)
Rodriguez, L.; Masías-Meza, J. J.; Dasso, S.; Démoulin, P.; Zhukov, A. N.; Gulisano, A. M.; Mierla, M.; Kilpua, E.; West, M.; Lacatus, D.; Paraschiv, A.; Janvier, M.
2016-08-01
Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs). They are important because of their simple internal magnetic field configuration, which resembles a magnetic flux rope, and because they represent one of the most geoeffective types of solar transients. In this study, we analyze their internal structure using a superposed epoch method on 63 events observed at L1 by the Advance Composition Explorer (ACE), between 1998 and 2006. In this way, we obtain an average profile for each plasma and magnetic field parameter at each point of the cloud. Furthermore, we take a fixed time-window upstream and downstream from the MC to also sample the regions preceding the cloud and the wake trailing it. We then perform a detailed analysis of the internal characteristics of the clouds and their surrounding solar wind environments. We find that the parameters studied are compatible with log-normal distribution functions. The plasma β and the level of fluctuations in the magnetic field vector are the best parameters to define the boundaries of MCs. We find that one third of the events shows a peak in plasma density close to the trailing edge of the flux ropes. We provide several possible explanations for this result and investigate if the density peak is of a solar origin ( e.g. erupting prominence material) or formed during the magnetic cloud travel from the Sun to 1 AU. The most plausible explanation is the compression due to a fast overtaking flow, coming from a coronal hole located to the east of the solar source region of the magnetic cloud.
Le, Cheng-feng; Li, Yun-mei; Zhang, Yun-lin; Sun, De-yong; Wu, Lan
2007-11-01
Using 64 stations water quality data collected in Taihu Lake, the spatial distribution of water color parameters and euphotic depth was analyzed, and the potential effect on hygrophyte photosynthesis was discussed. The result showed that the most variation was found for Chl a concentration, the value varies from 1.67 microg x L(-1) to 159.94 microg x L(-1), with the standard deviation of 41.03 mg x L(-1). The high Chl a concentration was recorded in Meiliang Bay, Zhushan Lake, Jiapu port and Xiaomei port with obviously spatial variation and compressive isoclines. The spatial variation of total suspended matter (TSM) concentration was lower than that of Chl a with a standard deviation of 31.63 mg x L(-1), and the concentration varies from 6.47 mg x L(-1) to 143.47 mg x L(-1). The high value was found in the area near Dapu port and Xiaomei port, with obviously spatial variation and compressive isoclines. No markedly spatial variation was found for colored dissolved organic matter (CDOM) in the whole lake. Euphotic depth was influenced by TSM and Chl a concentrations, while the influence by TSM was greater than that by Chl a. Therefore, the characteristics of spatial distribution for euphotic depth are reverse with TSM.
Kiran, Shumaila; Bhutta, Arif Mahmood; Khan, Bakhtyawar Ali; Durrani, Sobia; Ali, Muhammad; Ali, Muhammad; Iqbal, Furhan
2012-01-01
Objective To report and compare the hematological and serum biochemical profile of goat and sheep from Rahim Yar Khan district in Southern Punjab. Methods One hundred and twenty blood samples (98 goat and 22 sheep) were collected and their blood glucose, hemoglobin and serum biochemical parameters, cholesterol, aspartate transaminase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) were determined by using spectrophotometer. Parameters were compared between goat and sheep. Results It was observed that glucose (P=0.001), LDH (P=0.001) and ALT (P=0.001) concentrations differed significantly between sheep and goats. The studied parameters were compared between buck and goats and also between young goats (less than 12 months old) and adults (more than 12 months old). It was found that age and gender did not affect these hematological and serum biochemical parameters. Conclusions It can be concluded that sheep have overall higher values than goats for studied hematological and serum biochemical parameters. PMID:23569919
Elsner, Viviane Rostirola; Lovatel, Gisele Agustini; Moysés, Felipe; Bertoldi, Karine; Spindler, Christiano; Cechinel, Laura Reck; Muotri, Alysson Renato; Siqueira, Ionara Rodrigues
2013-02-01
Regular exercise improves learning and memory, including during aging process. Interestingly, the imbalance of epigenetic mechanisms has been linked to age-related cognitive deficits. However, studies about epigenetic alterations after exercise during the aging process are rare. In this preliminary study we investigated the effect of aging and exercise on DNA methyltransferases (DNMT1 and DNMT3b) and H3-K9 methylation levels in hippocampus from 3 and 20-months aged Wistar rats. The animals were submitted to two exercise protocols: single session or chronic treadmill protocol. DNMT1 and H3-K9 methylation levels were decreased in hippocampus from aged rats. The single exercise session decreased both DNMT3b and DNMT1 levels in young adult rats, without any effect in the aged group. Both exercise protocols reduced H3-K9 methylation levels in young adult rats, while the single session reversed the changes on H3-K9 methylation levels induced by aging. Together, these results suggest that an imbalance on DNMTs and H3-K9 methylation levels might be linked to the brain aging process and that the outcome to exercise seems to vary through lifespan.
Meliopoulos, Sakis; Cokkinides, George; Fardanesh, Bruce; Hedrington, Clinton
2013-12-31
This is the final report for this project that was performed in the period: October1, 2009 to June 30, 2013. In this project, a fully distributed high-fidelity dynamic state estimator (DSE) that continuously tracks the real time dynamic model of a wide area system with update rates better than 60 times per second is achieved. The proposed technology is based on GPS-synchronized measurements but also utilizes data from all available Intelligent Electronic Devices in the system (numerical relays, digital fault recorders, digital meters, etc.). The distributed state estimator provides the real time model of the system not only the voltage phasors. The proposed system provides the infrastructure for a variety of applications and two very important applications (a) a high fidelity generating unit parameters estimation and (b) an energy function based transient stability monitoring of a wide area electric power system with predictive capability. Also the dynamic distributed state estimation results are stored (the storage scheme includes data and coincidental model) enabling an automatic reconstruction and “play back” of a system wide disturbance. This approach enables complete play back capability with fidelity equal to that of real time with the advantage of “playing back” at a user selected speed. The proposed technologies were developed and tested in the lab during the first 18 months of the project and then demonstrated on two actual systems, the USVI Water and Power Administration system and the New York Power Authority’s Blenheim-Gilboa pumped hydro plant in the last 18 months of the project. The four main thrusts of this project, mentioned above, are extremely important to the industry. The DSE with the achieved update rates (more than 60 times per second) provides a superior solution to the “grid visibility” question. The generator parameter identification method fills an important and practical need of the industry. The “energy function” based
Peyman, A; Gabriel, C
2010-08-01
We have applied the Cole-Cole expression to the dielectric properties of tissues in the frequency range 0.4-10 GHz. The data underpinning the model relate to pig tissue as a function of age. Altogether, we provide the Cole-Cole parameters for 14 tissue types at three developmental stages.
NASA Technical Reports Server (NTRS)
Peters, B. C., Jr.; Walker, H. F.
1975-01-01
New results and insights concerning a previously published iterative procedure for obtaining maximum-likelihood estimates of the parameters for a mixture of normal distributions were discussed. It was shown that the procedure converges locally to the consistent maximum likelihood estimate as long as a specified parameter is bounded between two limits. Bound values were given to yield optimal local convergence.
The histories of ordinary chondrite parent bodies - U, Th-He age distributions
Wasson, J.T.; Wang, Sichao Purple Mountain Observatory, Nanjing )
1991-06-01
Age patterns observed in meteorite groups reflect the different thermal or impact histories experienced by their parent bodies. To assess the number of ordinary chondrite (OC) parent bodies, rare-gas data in the Schultz and Kruse (1989) data base were used to calculate U, Th-He gas-retention ages. Most H- and LL-chondrite ages are high; about 81 percent are greater than 2.2 Ga. In contrast, most L-chondrite ages are low; about 69 percent are not greater than 2.2 Ga, and about 35 percent are not greater than 0.9 Ga. The latter fraction is substantially lower than the value of 44 percent given by Heymann (1967). The difference is attributed to the preferential inclusion of shocked L chondrites in early studies. Broad age peaks in the H and LL groups near 3.4 Ga probably reflect thermal loss during metamorphism, but in the H distribution there is a hint of minor outgassing 'events' near 1 Ga. The L/LL chondrites have chemical properties intermediate between and unresolvable from L and LL chondrites. The high ages of most L/LL chondrites are evidence against these originating on the L parent body; the L/LL age distribution is consistent with an origin on the LL parent body or on an independent body. 22 refs.
The histories of ordinary chondrite parent bodies - U, Th-He age distributions
NASA Astrophysics Data System (ADS)
Wasson, John T.; Wang, Sichao
1991-06-01
Age patterns observed in meteorite groups reflect the different thermal or impact histories experienced by their parent bodies. To assess the number of ordinary chondrite (OC) parent bodies, rare-gas data in the Schultz and Kruse (1989) data base were used to calculate U, Th-He gas-retention ages. Most H- and LL-chondrite ages are high; about 81 percent are greater than 2.2 Ga. In contrast, most L-chondrite ages are low; about 69 percent are not greater than 2.2 Ga, and about 35 percent are not greater than 0.9 Ga. The latter fraction is substantially lower than the value of 44 percent given by Heymann (1967). The difference is attributed to the preferential inclusion of shocked L chondrites in early studies. Broad age peaks in the H and LL groups near 3.4 Ga probably reflect thermal loss during metamorphism, but in the H distribution there is a hint of minor outgassing "events" near 1 Ga. The L/LL chondrites have chemical properties intermediate between and unresolvable from L and LL chondrites. The high ages of most L/LL chondrites are evidence against these originating on the L parent body; the L/LL age distribution is consistent with an origin on the LL parent body or on an independent body.
Aging Management Guideline for commercial nuclear power plants: Power and distribution transformers
Toman, G.; Gazdzinski, R.
1994-05-01
This Aging Management Guideline (AMG) provides recommended methods for effective detection and mitigation of age-related degradation mechanisms in power and distribution transformers important to license renewal in commercial nuclear power plants. The intent of this AMG to assist plant maintenance and operations personnel in maximizing the safe, useful life of these components. It also supports the documentation of effective aging management programs required under the License Renewal Rule 10 CFR Part 54. This AMG is presented in a manner which allows personnel responsible for performance analysis and maintenance to compare their plant-specific aging mechanisms (expected or already experienced) and aging management program activities to the more generic results and recommendations presented herein.
EFFECTS OF TOLUENE ON BRAIN OXIDATIVE STRESS PARAMETERS IN AGING BROWN NORWAY RATS
Aging-related susceptibility to environmental chemicals is poorly understood. Oxidative stress (OS) appears to play an important role in susceptibility and disease in old age. The objectives of this study, therefore, were to test whether OS is a potential toxicity pathway for tol...
ERIC Educational Resources Information Center
Sowerby, Paula; Seal, Simon; Tripp, Gail
2011-01-01
Objective: To further define the nature of working memory (WM) impairments in children with combined-type ADHD. Method: A total of 40 Children with ADHD and an age and gender-matched control group (n = 40) completed two measures of visuo-spatial WM and two measures of verbal WM. The effects of age and learning/language difficulties on performance…
Göthe, Katrin; Esser, Günther; Gendt, Anja; Kliegl, Reinhold
2012-03-01
Parameters of a formal working-memory model were estimated for verbal and spatial memory updating of children. The model proposes interference though feature overwriting and through confusion of whole elements as the primary cause of working-memory capacity limits. We tested 2 age groups each containing 1 group of normal intelligence and 1 deficit group. For young children the deficit was developmental dyslexia; for older children it was a general learning difficulty. The interference model predicts less interference through overwriting but more through confusion of whole elements for the dyslexic children than for their age-matched controls. Older children exhibited less interference through confusion of whole elements and a higher processing rate than young children, but general learning difficulty was associated with slower processing than in the age-matched control group. Furthermore, the difference between verbal and spatial updating mapped onto several meaningful dissociations of model parameters.
Liao, Yi-Hua; Chen, Szu-Yu; Chou, Sin-Yo; Wang, Pei-Hsun; Tsai, Ming-Rung; Sun, Chi-Kuang
2012-01-01
Skin aging is an important issue in geriatric and cosmetic dermatology. To quantitatively analyze changes in keratinocytes related to intrinsic aging, we exploited a 1230 nm-based in vivo harmonic generation microscopy, combining second- and third-harmonic generation modalities. 52 individuals (21 men and 31 women, age range 19–79) were examined on the sun-protected volar forearm. Through quantitative analysis by the standard algorithm provided, we found that the cellular and nuclear size of basal keratinocytes, but not that of granular cells, was significantly increased with advancing age. The cellular and nuclear areas, which have an increase of 0.51 μm2 and 0.15 μm2 per year, respectively, can serve as scoring indices for intrinsic skin aging. PMID:23304649
NASA Astrophysics Data System (ADS)
Becker, T. W.; Conrad, C. P.; Buffett, B.; Muller, D.; Loyd, S.; Lithgow-Bertelloni, C.; Corsetti, F.
2008-12-01
Variations in the rates of seafloor generation and recycling have potentially far-reaching consequences for sea level, ocean chemistry and climate. A parameterized framework to describe such variations could guide the study of non-uniformitarian plate tectonic activity, but there is little agreement on the appropriate mechanical description of the surface boundary layer. A strong constraint on the statistics of oceanic convection systems comes from the preserved seafloor age distribution, and additional inferences are possible when paleo-seafloor is modeled based on plate motion reconstructions. Based on previously reconstructed seafloor ages, we recently inferred that oceanic heat flow was larger by ~15% at 60~Ma than today. This signal is mainly caused by the smaller plates that existed previously in the Pacific basin with relatively larger ridge-proximal area of young seafloor. The associated decrease in heat flow is larger than any plausible decrease due to cooling, and therefore hint at cyclic behavior in plate tectonics. We also consider area-per-age statistics for the present-day and back to 140~Ma from new paleo-age reconstructions. Using a simplified seafloor age evolution model we explore which physical parameterizations for the average behavior of the oceanic lithosphere are compatible with broad trends in the data. In particular, we show that a subduction probability based on lithospheric buoyancy ("sqrt(age)") leads to results that are comparable to, or better than, that of the probability distribution that is required to obtain the "triangular" age distribution with age-independent destruction of ocean floor. The current, near triangular distribution of ages and the relative lull in heat flow are likely only snapshots of a transient state during the Wilson cycle. Current seafloor ages still contain hints of a ≤sssim 60~Myr period, cyclic variation of seafloor production, and using paleo-ages for 140~Ma, we find a ~ 400~Myr best-fitting variation
Impact of Hydrologic Variability on Nutrient Age Distribution in Intensively Managed Landscapes
NASA Astrophysics Data System (ADS)
Kumar, P.; Woo, D. K.
2014-12-01
The distribution, concentration, and transport of nutrients in agricultural landscapes are of significant societal concern. Our interests in reactive nitrogen and the nitrogen cycle have shifted from increasing the efficiency of nitrogen delivery to target crop species to decreasing environmental damage caused by intensive agricultural practices. Enhancing the reactive nitrogen use efficiency to increase food production to meet future demand inevitably contributes to an increase in the reactive nitrogen load in the ecosystem, and damaging the environment. However, due to the complexity of the nitrogen cycle, the dynamics of nitrogen in soils and its interactions with ecohydrological processes at the watershed and regional scales are not well understood to enable adequate remedial measures. To unravel the complexity of this dynamics we have developed a model for characterizing the nitrogen age (elapsed time) distribution. The goal of our study is to develop and analyze the dynamics of nitrogen in the context of age and transit times resulting from advection, mixing, and production/destruction processes; evaluate the effects of micro-topographic variability on the nitrogen age distributions; and investigate how the temporal dynamics of the nitrogen age distribution are affected by changes in the variability of climate drivers. Our study is performed for the Upper Sangamon River Basin in the Critical Zone Observatory for Intensively Managed Landscapes (IML-CZO).
Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In situ Rice Roots
The speciation and distribution of cobalt (Co) in soils is poorly understood. This study was conducted using X-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble Co(II) aging, submergence-dried cycling, and the presence of in vivo rice roots on the...
Age Dating Fluvial Sediment Storage Reservoirs to Construct Sediment Waiting Time Distributions
NASA Astrophysics Data System (ADS)
Skalak, K.; Pizzuto, J. E.; Benthem, A.; Karwan, D. L.; Mahan, S.
2015-12-01
Suspended sediment transport is an important geomorphic process that can often control the transport of nutrients and contaminants. The time a particle spends in storage remains a critical knowledge gap in understanding particle trajectories through landscapes. We dated floodplain deposits in South River, VA, using fallout radionuclides (Pb-210, Cs-137), optically stimulated luminescence (OSL), and radiocarbon dating to determine sediment ages and construct sediment waiting time distributions. We have a total of 14 age dates in two eroding banks. We combine these age dates with a well-constrained history of mercury concentrations on suspended sediment in the river from an industrial release. Ages from fallout radionuclides document sedimentation from the early 1900s to the present, and agree with the history of mercury contamination. OSL dates span approximately 200 to 17,000 years old. We performed a standard Weibull analysis of nonexceedance to construct a waiting time distribution of floodplain sediment for the South River. The mean waiting time for floodplain sediment is 2930 years, while the median is approximately 710 years. When the floodplain waiting time distribution is combined with the waiting time distribution for in-channel sediment storage (available from previous studies), the mean waiting time shifts to approximately 680 years, suggesting that quantifying sediment waiting times for both channel and floodplain storage is critical in advancing knowledge of particle trajectories through watersheds.
Recent Changes in the U.S. Age at Death Distribution: Further Observations.
ERIC Educational Resources Information Center
Myers, George C.; Manton, Kenneth G.
1984-01-01
Responds to discussion (Fries, 1984) of an earlier article (Myers and Manton, 1984) presenting empirical evidence on changes in the distribution of ages at death. Further analysis of the data is presented, including life expectancy changes from 1950-1978 and comparison of data for men and women from several countries. (JAC)
Age distribution curve in psychiatric admissions inversely correlates with Life Satisfaction.
Le Bon, Olivier; Le Bon, Serge-Daniel
2014-09-30
A strong inverse correlation was found between the age-distribution curve of psychiatric admissions and the U-bend Life Satisfaction curve. It may indicate that the peak of mental disorders at midlife reflects a less satisfactory period of life or, conversely, that the mental health load burdens of Life Satisfaction.
Cam, E.; Monnat, J.-Y.
2000-01-01
Heterogeneity in individual quality can be a major obstacle when interpreting age-specific variation in life-history traits. Heterogeneity is likely to lead to within-generation selection, and patterns observed at the population level may result from the combination of hidden patterns specific to subpopulations. Population-level patterns are not relevant to hypotheses concerning the evolution of age-specific reproductive strategies if they differ from patterns at the individual level. We addressed the influence of age and a variable used as a surrogate of quality (yearly reproductive state) on survival and breeding probability in the kittiwake. We found evidence of an effect of age and quality on both demographic parameters. Patterns observed in breeders are consistent with the selection hypothesis, which predicts age-related increases in survival and traits positively correlated with survival. Our results also reveal unexpected age effects specific to subgroups: the influence of age on survival and future breeding probability is not the same in nonbreeders and breeders. These patterns are observed in higher-quality breeding habitats, where the influence of extrinsic factors on breeding state is the weakest. Moreover, there is slight evidence of an influence of sex on breeding probability (not on survival), but the same overall pattern is observed in both sexes. Our results support the hypothesis that age-related variation in demographic parameters observed at the population level is partly shaped by heterogeneity among individuals. They also suggest processes specific to subpopulations. Recent theoreticaI developments lay emphasis on integration of sources of heterogeneity in optimization models to account for apparently 'sub-optimal' empirical patterns. Incorporation of sources of heterogeneity is also the key to investigation of age-related reproductive strategies in heterogeneous populations. Thwarting 'heterogeneity's ruses' has become a major challenge: for
NASA Astrophysics Data System (ADS)
Chen, Jinsong; Hubbard, Susan S.; Williams, Kenneth H.; Flores Orozco, AdriáN.; Kemna, Andreas
2012-05-01
We developed a hierarchical Bayesian model to estimate the spatiotemporal distribution of aqueous geochemical parameters associated with in-situ bioremediation using surface spectral induced polarization (SIP) data and borehole geochemical measurements collected during a bioremediation experiment at a uranium-contaminated site near Rifle, Colorado (USA). The SIP data were first inverted for Cole-Cole parameters, including chargeability, time constant, resistivity at the DC frequency, and dependence factor, at each pixel of two-dimensional grids using a previously developed stochastic method. Correlations between the inverted Cole-Cole parameters and the wellbore-based groundwater chemistry measurements indicative of key metabolic processes within the aquifer (e.g., ferrous iron, sulfate, uranium) were established and used as a basis for petrophysical model development. The developed Bayesian model consists of three levels of statistical submodels: (1) data model, providing links between geochemical and geophysical attributes, (2) process model, describing the spatial and temporal variability of geochemical properties in the subsurface system, and (3) parameter model, describing prior distributions of various parameters and initial conditions. The unknown parameters were estimated using Markov chain Monte Carlo methods. By combining the temporally distributed geochemical data with the spatially distributed geophysical data, we obtained the spatiotemporal distribution of ferrous iron, sulfate, and sulfide, and their associated uncertainty information. The obtained results can be used to assess the efficacy of the bioremediation treatment over space and time and to constrain reactive transport models.
Berianidze, K; Katsitadze, A; Sanikidze, T
2016-01-01
Purpose of study was to investigate the alteration of oxidative and immunological metabolism in blood of reproductive and menopausal age women after UVA irradiation. Women of two groups (1 - menopausal, 2 - reproductive age) were exposed to radiation with wave length 320-400 nm for 5-10 minutes per session in the solarium for the period of 3 months (6 days per month).. Parameters of oxidative metabolism - activity of red blood cells (RBC), antioxidant enzymes catalase (CAT) and superoxiddismutase (SOD) were studied by spectrophotometric method; reactive oxygen (O2-) and lipid (LOO/) free radicals content in whole blood were studied by Electron Paramagnetic Resonance (EPR) methods with use of specific spin-traps - 5,5-Dimethyl-1-Pyrroline-N-Oxide (DMPO) and α-phenyl-N-tert-butylnitrone (PBN) (SIGMA). Parameters of immunological metabolism - IFN-α, IL-2, IL-10 cytokines content in blood were studied by immunoenzymatic assay ELISA. The study protocol has been approved by the Ethical Committee of the Tbilisi State Medical University. After the course of UVA irradiation in menopausal women CAT activity increased by 20%, SOD - by 24%, and EPR signal of spin trapped lipoperoxide radicals was detected. No alterations in blood redox-balance were detected in women of reproductive age. Values of blood immunological parameters in menopausal women were not changed under the influence of UV radiation; in women of reproductive age IL-10 content increase by 93% (within a normal value range) was revealed. Research results have shown that UVA rays cause a particularly significant influence on the oxidative metabolism in the women of menopausal age. Increase of IL-10 blood levels in women of reproductive age (considering its imunosupressing activity) represents an additional risk of cancerogenesis. Based on the study results, we recommend avoiding UV (including UVA) radiation procedures to women of both reproductive and menopausal ages. PMID:26870984
Pelletier, Amandine; Periot, Olivier; Dilharreguy, Bixente; Hiba, Bassem; Bordessoules, Martine; Chanraud, Sandra; Pérès, Karine; Amieva, Hélène; Dartigues, Jean-François; Allard, Michèle; Catheline, Gwénaëlle
2016-01-01
Microstructural changes of White Matter (WM) associated with aging have been widely described through Diffusion Tensor Imaging (DTI) parameters. In parallel, White Matter Hyperintensities (WMH) as observed on a T2-weighted MRI are extremely common in older individuals. However, few studies have investigated both phenomena conjointly. The present study investigates aging effects on DTI parameters in absence and in presence of WMH. Diffusion maps were constructed based on 21 directions DTI scans of young adults (n = 19, mean age = 33 SD = 7.4) and two age-matched groups of older adults, one presenting low-level-WMH (n = 20, mean age = 78, SD = 3.2) and one presenting high-level-WMH (n = 20, mean age = 79, SD = 5.4). Older subjects with low-level-WMH presented modifications of DTI parameters in comparison to younger subjects, fitting with the DTI pattern classically described in aging, i.e., Fractional Anisotropy (FA) decrease/Radial Diffusivity (RD) increase. Furthermore, older subjects with high-level-WMH showed higher DTI modifications in Normal Appearing White Matter (NAWM) in comparison to those with low-level-WMH. Finally, in older subjects with high-level-WMH, FA, and RD values of NAWM were associated with to WMH burden. Therefore, our findings suggest that DTI modifications and the presence of WMH would be two inter-dependent processes but occurring within different temporal windows. DTI changes would reflect the early phase of white matter changes and WMH would appear as a consequence of those changes. PMID:26834625
Influence of bone parameters on peri-implant bone strain distribution in the posterior mandible
Yamamoto, Kazuhiko; Kawakami, Masayoshi; Horita, Satoshi; Murakami, Kazuhiro; Kirita, Tadaaki
2015-01-01
Objectives: The success rate of dental implants depends on the type of bone at the implant site. The purpose of the present study was to investigate the effects of the bone parameters at the implant-placement site on peri-implant bone strain distributions. Study Design: The morphologies and bone densities of seventy-five potential implant sites in the posterior mandible were measured using computed tomography (CT). Based on the CT data, we defined bone parameters (low and high in terms of cancellous-bone density and crestal-cortical bone density, and thin and thick in terms of crestal-cortical bone thickness), and we constructed finite-element models simulating the various bone types. A buccolingual oblique load of 200 N was applied to the top of the abutment. The von Mises equivalent (EQV) strains in the crestal-cortical bone and in the cancellous bone around the implant were calculated. Results: Cancellous-bone density greatly affected the maximum EQV strain regardless of the density and thickness of the crestal cortical-bone. The maximum EQV strains in the crestal cortical-bone and the cancellous bone in the low-density cancellous-bone models (of 150 Hounsfield units (HU) were 1.56 to 2.62-fold and 3.49 to 5.31-fold higher than those in the high-density cancellous-bone models (of 850 HU), respectively. The crestal cortical-bone density affected the maximum EQV strains in the crestal cortical-bone and in the cancellous bone in the low-density cancellous-bone models. The crestal cortical-bone thickness affected the maximum EQV strains in the cancellous bone and in the crestal cortical-bone in the low-density cancellous-bone models. Conclusions: Our results confirm the importance of bone types for the peri-implant bone strain distribution. Cancellous-bone density may be a critical factor for peri-implant bone strain. Key words:Dental implant, bone density, finite-element analysis. PMID:25129251
Prevalence of dominant mutations in Spain: effect of changes in maternal age distribution.
Martínez-Frías, M L; Herranz, I; Salvador, J; Prieto, L; Ramos-Arroyo, M A; Rodríguez-Pinilla, E; Cordero, J F
1988-12-01
We studied the birth prevalence of autosomal dominant mutations in Spain and estimated how a decrease in maternal age distribution may lead to reduction in dominant mutations. The data were collected by the Estudio Colaborativo Español de Malformaciones Congénitas from April, 1976, to December, 1985. Among 553,270 liveborn infants monitored during the period, 66 infants with autosomal dominant conditions were identified. These included Apert, Crouzon, Hay-Wells, Treacher-Collins, Robinow, Stickler, Adams-Oliver, and the blepharophimosis syndromes, achondroplasia, cleidocranial dysostosis, and thanatophoric dysplasia. The overall rate of autosomal dominant conditions was 1.2 per 10,000 liveborn infants. Thirteen (20%) had an affected relative, and 52 (79%) had a negative family history. One case was excluded because of insufficient family data. The rate of autosomal dominant mutations was 0.9 per 10,000 liveborn infants, or 47 per 1 million gametes. A reduction in the maternal age distribution of mothers age 35 years and older from the current 10.8% to 4.9%, as in Atlanta, Georgia, would reduce the rate of Down syndrome in Spain by 33% and through a change in parternal age distribution may lead to a reduction in dominant mutations of about 9.6%. This suggests that a public health campaign to reduce older maternal age distribution in Spain may also lead to a reduction in dominant mutations and emphasizes the potential that a direct campaign for fathers to complete their families before age 35 years may have a small, but measurable, effect in the primary prevention of dominant mutations.
Relative measurement of acoustic nonlinear parameters and comparison of sensitivity to thermal aging
NASA Astrophysics Data System (ADS)
Seo, Hogeon; Ren, Gang; Kim, Jongbeom; Jhang, Kyung-Young
2015-03-01
The acoustic nonlinearity measurement of ultrasonic waves are being extensively researched as a promising nondestructive evaluation element. In the condition of constant propagation distance and wave number, many researchers have measured the second-order relative acoustic nonlinear parameter, β', that can be simply defined as the ratio of the amplitude of the second harmonic frequency component to the amplitude squared of the fundamental frequency component and compared them in order to identify the acoustic nonlinearity variation according to material degradation. In this study, we extended this concept to the third-order relative acoustic nonlinear parameter, γ', by defining it as the ratio of the amplitude of the third harmonic frequency component to the amplitude cubed of the fundamental frequency component. To investigate its effectiveness as a nondestructive evaluation element for the material property degradation, both the second-order acoustic relative nonlinear parameter and the third-order relative acoustic nonlinear parameter were measured for the aluminum specimens processed by heat treatment for the different times and then contrasted each other. From the experimental results, the third-order acoustic relative nonlinear parameter was more sensitive than the second-order relative acoustic nonlinear parameter that has been widely used although the amplitude of the third harmonic frequency component was lower than the amplitude of the second harmonic frequency component.
Liu, Chen; Guan, Zhao; Xu, Qinzhu; Zhao, Lei; Song, Ying; Wang, Hui
2016-01-01
Abstract Fractures are common among aged people, and rapid assessment of the coagulation status is important. The thromboelastography (TEG) test can give a series of coagulation parameters and has been widely used in clinics. In this research, we looked at fracture patients over 60 and compared their TEG results with those of healthy controls. Since there is a paucity of studies comparing TEG assessments with conventional coagulation tests, we aim to clarify the relationship between TEG values and the values given by conventional coagulation tests. Forty fracture patients (27 femur and 13 humerus) over 60 years old were included in the study. The change in their coagulation status was evaluated by TEG before surgery within 4 hours after the fracture. Changes in TEG parameters were analyzed compared with controls. Conventional coagulation test results for the patients, including activated partial thromboplastin time (APTT), international normalized ratio (INR), fibrinogen, and platelets, were also acquired, and correlation analysis was done with TEG parameters, measuring similar aspects of the coagulation cascade. In addition, the sensitivity and specificity of TEG parameters for detecting raised fibrinogen levels were also analyzed. The K (time to 20 mm clot amplitude) and R (reaction time) values of aged fracture patients were lower than controls. The values for angle, maximal amplitude (MA), and coagulation index (CI) were raised compared with controls, indicating a hypercoagulable state. Correlation analysis showed that there were significant positive correlations between fibrinogen and MA/angle, between platelets and MA, and between APTT and R as well. There was significant negative correlation between fibrinogen and K. In addition, K values have better sensitivity and specificity for detecting elevated fibrinogen concentration than angle and MA values. Aged fracture patients tend to be in a hypercoagulable state, and this could be effectively reflected by
NASA Astrophysics Data System (ADS)
Woo, D.; Kumar, P.
2015-12-01
Excess reactive nitrogen in soils of intensively managed agricultural fields causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a 3-dimensional model to characterize the spatially distributed ``age" of soil-nitrogen (nitrate and ammonia-ammonium) across a watershed. We use the general theory of age, which provides an assessment of the elapsed time since nitrogen is introduced into the soil system. Micro-topographic variability incorporates heterogeneity of nutrient transformations and transport associated with topographic depressions that form temporary ponds and produce prolonged periods of anoxic conditions, and roadside agricultural ditches that support rapid surface movement. This modeling effort utilizes 1-m Light Detection and Ranging (LiDAR) data. We find a significant correlation between hydrologic variability and mean nitrate age that enables assessment of preferential flow paths of nitrate leaching. The estimation of the mean nitrogen age can thus serve as a tool to disentangle complex nitrogen dynamics by providing the analysis of the time scales of soil-nitrogen transformation and transport processes without introducing additional parameters.
Kinetic parameters and tissue distribution of 5-oxo-L-prolinase determined by a fluorimetric assay.
Weber, P; Jäger, M; Bangsow, T; Knell, G; Piechaczek, K; Koch, J; Wolf, S
1999-01-13
5-Oxo-L-prolinase (5-OPase) catalyses the hydrolysis of 5-oxo-L-proline to glutamate with concomitant stoichiometric cleavage of ATP to ADP, a reaction which is known to be part of the gamma-glutamyl cycle-an interrelated series of reactions involved in the synthesis and metabolism of glutathione. As recent studies indicate, this cyclic pathway plays a crucial role in the regulation of amino acid transport. Apparently, the intermediate product 5-oxo-L-proline functions as a second messenger molecule that upregulates the activity of certain amino acid transport systems. Thus, the degradation of 5-oxo-L-proline by 5-OPase leads to the downregulation of this stimulus. In this study, a new sensitive fluorimetric assay for 5-OPase activity was established which is based on the derivatization of glutamate with o-phthaldialdehyde in the presence of thiols and subsequent separation of the products by HPLC. The method is suitable for the screening of chromatography fractions as well as for the determination of the kinetic parameters Km and Vmax of purified 5-OPase. Additionally, it can be used for the measurement of enzyme activity in crude cell extracts and evaluation of tissue distribution.
Spectral energy distributions and model atmosphere parameters of the quadruple system ADS11061.
NASA Astrophysics Data System (ADS)
Al-Wardat, M. A.
2002-06-01
The spectral energy distribution between λ 3700 Å, and λ 8100 Å, of the two subsystems 41Dra and 40Dra of the multiple system ADS11061 has been introduced with a description of methodology of getting the spectra on Carl-Zeiss-Jena 1 m telescope of Special Astrophysical Observatory. The spectral type and luminosity class for each of them have been deduced and compared with earlier investigations, the B,V, and R magnitudes and B-V colour indices have been computed, the interstellar reddening of both subsystems have been calculated and an envelope around 40Dra has been suggested, model atmosphere parameters of the subsystem 40Dra' components have been derived: TeffBa =6100 degr K, TeffBb =6100 degr K, lg gBa=4.03, lg gBb=4.20, RBa=1.82R⊙, RBb=1.44R⊙, and finally the formation and evolution of the system have been discussed depending on the filament fragmentation process.
Klencsár, Zoltán
2014-10-27
Accurate quantitative analysis of Mössbauer spectra displaying thickness effects requires the consideration of the so-called transmission integral when modeling the spectral shape. Whereas this is straightforward when the correct model for the decomposition of the absorber's nuclear resonance absorption cross-section into individual components is a priori known, in the absence of such knowledge and notably in the presence of hyperfine parameter distributions with an unknown profile, the so-called model-independent evaluation methods could be used to fit the spectra. However, the methods available for this purpose were developed for the analysis of spectra for which the thin absorber approximation is valid, and thus they do not take the sample thickness and related effects into account. Consequently, in order to use them for spectra displaying thickness effects, their usage needs to be generalized by combining them with transmission integral fitting. A new algorithm realizing such a generalized version of the Hesse-Rübartsch model-independent evaluation method was developed recently as an integral part of the MossWinn program. In the present work, the working principle of the newly developed algorithm is described in details along with examples illustrating the capabilities of the method for the case of {sup 57}Fe Mössbauer spectroscopy.
Giangrande S. E.; Luke, E. P.; Kollias, P.
2012-02-01
Extended, high-resolution measurements of vertical air motion and median volume drop diameter D0 in widespread precipitation from three diverse Atmospheric Radiation Measurement Program (ARM) locations [Lamont, Oklahoma, Southern Great Plains site (SGP); Niamey, Niger; and Black Forest, Germany] are presented. The analysis indicates a weak (0-10 cm{sup -1}) downward air motion beneath the melting layer for all three regions, a magnitude that is to within the typical uncertainty of the retrieval methods. On average, the hourly estimated standard deviation of the vertical air motion is 0.25 m s{sup -1} with no pronounced vertical structure. Profiles of D0 vary according to region and rainfall rate. The standard deviation of 1-min-averaged D0 profiles for isolated rainfall rate intervals is 0.3-0.4 mm. Additional insights into the form of the raindrop size distribution are provided using available dual-frequency Doppler velocity observations at SGP. The analysis suggests that gamma functions better explain paired velocity observations and radar retrievals for the Oklahoma dataset. This study will be useful in assessing uncertainties introduced in the measurement of precipitation parameters from ground-based and spaceborne remote sensors that are due to small-scale variability.
Vibration suppression of distributed parameter flexible structures by Integral Consensus Control
NASA Astrophysics Data System (ADS)
Omidi, Ehsan; Mahmoodi, S. Nima
2016-03-01
Integral Consensus Control (ICC) is proposed and implemented in this paper for the first time, as a novel approach for vibration control in distributed parameter flexible structures. The ICC consists of multiple parallel first-order lossy integrators, with the goal of targeting all major participating resonant modes in the oscillation of the structure. The vibration control design is taken to a different level, by integrating the concept of consensus control design into the new dynamics. Each control patch on the flexible structure is considered as a node of a network, and a communication topology with consensus control terms are augmented in the controller design dynamics. The result is an effective vibration controller, which is also robust to failures and inconsistencies in the control system. A cantilever is used as a sample flexible structure to investigate the control method. Multi-agent representation of the system, state estimator dynamics and the ICC model are designed for the structure. Extensive numerical simulations have been conducted to show the suppression performance of the ICC under different input disturbances. A comparative study is presented to show the advantage of the decentralized design over the conventional centralized approach. The new consensus control design provides new possibilities to vibration control problems, where an effective, robust and synchronized suppression is needed.
Büttner, Kathrin; Scheffler, Katharina; Czycholl, Irena; Krieter, Joachim
2015-01-01
Knowledge of the network structure of agonistic interactions helps to understand the formation and the development of aggressive behavior. Therefore, video observation data of 149 pigs over three different age levels were investigated for 2 days each directly after mixing (65 groups in the rearing area, 24 groups in the growing stable and 12 groups in the breeding stable). The aim of the study was to use network analysis to investigate the development of individual network positions of specific animals and to determine whether centrality parameters in previous mixing situations have an impact on the future behavior of the animals. The results of the weighted degree centrality indicated that weaned pigs had a higher fighting intensity directly after mixing compared to growing pigs and gilts. Also, the number of different opponents (degree centrality) was higher compared to the older age groups. The betweenness centrality showed relatively small values and no significant differences between the different age levels, whereas the closeness centrality showed high values at all observed age levels. Experiences gained in previous agonistic interactions had an impact on the centrality parameters in subsequent mixing situations. It was shown that the position of individual animals in agonistic interaction networks can be characterized using social network analysis and that changes over different age levels can be detected. Therefore, social network analysis provides insights into the formation and evolution of behavioral patterns which could be of particular interest for the identification of key factors with regard to abnormal behavior (e.g. tail biting). PMID:25932371
Brouwers, Barbara; Hatse, Sigrid; Lago, Lissandra Dal; Neven, Patrick; Vuylsteke, Peter; Dalmasso, Bruna; Debrock, Guy; Van Den Bulck, Heidi; Smeets, Ann; Bechter, Oliver; Bailur, Jithendra Kini; Kenis, Cindy; Laenen, Annouschka; Schöffski, Patrick; Pawelec, Graham; Journe, Fabrice; Ghanem, Ghanem-Elias; Wildiers, Hans
2016-01-01
Purpose This prospective observational study aimed to evaluate the impact of adjuvant chemotherapy on biological and clinical markers of aging and frailty. Methods Women ≥ 70 years old with early breast cancer were enrolled after surgery and assigned to a chemotherapy (Docetaxel and Cyclophosphamide) group (CTG, n=57) or control group (CG, n=52) depending on their planned adjuvant treatment. Full geriatric assessment (GA) and Quality of Life (QoL) were evaluated at inclusion (T0), after 3 months (T1) and at 1 year (T2). Blood samples were collected to measure leukocyte telomere length (LTL), levels of interleukin-6 (IL-6) and other circulating markers potentially informative for aging and frailty: Interleukin-10 (IL-10), Tumor Necrosis Factor Alpha (TNF-α), Insulin-like Growth Factor 1 (IGF-1), Monocyte Chemotactic Protein 1 (MCP-1) and Regulated on Activation, Normal T cell Expressed and Secreted (RANTES). Results LTL decreased significantly but comparably in both groups, whereas IL-6 was unchanged at T2. However, IL-10, TNF-α, IGF-1 and MCP-1 suggested a minor biological aging effect of chemotherapy. Clinical frailty and QoL decreased at T1 in the CTG, but recovered at T2, while remaining stable in the CG. Conclusion Chemotherapy (TC) is unlikely to amplify clinical aging or induce frailty at 1 year. Accordingly, there is no impact on the most established aging biomarkers (LTL, IL-6). PMID:27102154
2016-01-01
Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20–30 years) and 18 older (60–85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes. PMID:27610379
2016-01-01
Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20–30 years) and 18 older (60–85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes.
Siddiqi, Ariba; Arjunan, Sridhar Poosapadi; Kumar, Dinesh Kant
2016-01-01
Age-related neuromuscular change of Tibialis Anterior (TA) is a leading cause of muscle strength decline among the elderly. This study has established the baseline for age-associated changes in sEMG of TA at different levels of voluntary contraction. We have investigated the use of Gaussianity and maximal power of the power spectral density (PSD) as suitable features to identify age-associated changes in the surface electromyogram (sEMG). Eighteen younger (20-30 years) and 18 older (60-85 years) cohorts completed two trials of isometric dorsiflexion at four different force levels between 10% and 50% of the maximal voluntary contraction. Gaussianity and maximal power of the PSD of sEMG were determined. Results show a significant increase in sEMG's maximal power of the PSD and Gaussianity with increase in force for both cohorts. It was also observed that older cohorts had higher maximal power of the PSD and lower Gaussianity. These age-related differences observed in the PSD and Gaussianity could be due to motor unit remodelling. This can be useful for noninvasive tracking of age-associated neuromuscular changes. PMID:27610379
The Age, Mass, and Size Distributions of Star Clusters in M51
NASA Astrophysics Data System (ADS)
Chandar, Rupali; Whitmore, Bradley C.; Dinino, Daiana; Kennicutt, Robert C.; Chien, L.-H.; Schinnerer, Eva; Meidt, Sharon
2016-06-01
We present a new catalog of 3816 compact star clusters in the grand design spiral galaxy M51 based on observations taken with the Hubble Space Telescope. The age distribution of the clusters declines starting at very young ages, and can be represented by a power law, {dN}/dτ \\propto {τ }γ , with γ =-0.65+/- 0.15. No significant changes in the shape of the age distribution at different masses is observed. The mass function of the clusters younger than τ ≈ 400 {{Myr}} can also be described by a power law, {dN}/{dM}\\propto {M}β , with β ≈ \\-2.1+/- 0.2. We compare these distributions with the predictions from various cluster disruption models, and find that they are consistent with models where clusters disrupt approximately independent of their initial mass, but not with models where lower mass clusters are disrupted earlier than their higher mass counterparts. We find that the half-light radii of clusters more massive than M ≈ 3× {10}4 {M}⊙ and with ages between 100 and 400 {{Myr}} are larger by a factor of ≈3-4 than their counterparts that are younger than 107 years old, suggesting that the clusters physically expand during their early life.
Reconstructing merger timelines using star cluster age distributions: the case of MCG+08-11-002
NASA Astrophysics Data System (ADS)
Davies, Rebecca L.; Medling, Anne M.; U, Vivian; Max, Claire E.; Sanders, David; Kewley, Lisa J.
2016-05-01
We present near-infrared imaging and integral field spectroscopy of the centre of the dusty luminous infrared galaxy merger MCG+08-11-002, taken using the Near InfraRed Camera 2 (NIRC2) and the OH-Suppressing InfraRed Imaging Spectrograph (OSIRIS) on Keck II. We achieve a spatial resolution of ˜25 pc in the K band, allowing us to resolve 41 star clusters in the NIRC2 images. We calculate the ages of 22/25 star clusters within the OSIRIS field using the equivalent widths of the CO 2.3 μm absorption feature and the Br γ nebular emission line. The star cluster age distribution has a clear peak at ages ≲ 20 Myr, indicative of current starburst activity associated with the final coalescence of the progenitor galaxies. There is a possible second peak at ˜65 Myr which may be a product of the previous close passage of the galaxy nuclei. We fit single and double starburst models to the star cluster age distribution and use Monte Carlo sampling combined with two-sided Kolmogorov-Smirnov tests to calculate the probability that the observed data are drawn from each of the best-fitting distributions. There is a >90 per cent chance that the data are drawn from either a single or double starburst star formation history, but stochastic sampling prevents us from distinguishing between the two scenarios. Our analysis of MCG+08-11-002 indicates that star cluster age distributions provide valuable insights into the timelines of galaxy interactions and may therefore play an important role in the future development of precise merger stage classification systems.
Büsse, Sebastian; von Grumbkow, Philipp; Hummel, Susanne; Shah, Deep Narayan; Tachamo Shah, Ram Devi; Li, Jingke; Zhang, Xueping; Yoshizawa, Kazunori; Wedmann, Sonja; Hörnschemeyer, Thomas
2012-01-01
Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata.
Gabutti, G; Stefanati, A; Kuhdari, P
2015-01-01
Notwithstanding different meningococcal serogroups have changed their distribution and their impact in different age classes over time, N. meningitidis' invasive diseases are a major public health issue worldwide, due to the related complications and severe sequelae. Nowadays, the highest rates of invasive disease are registered in children younger than 1 year of age, with a second lesser peak in adolescents and young adults (15-25 years of age). On the contrary, the prevalence of carriage is low in newborns and in school-age children, and increases during adolescence and young-adult age; then it decreases again in older age. N. meningitidis' infection prevalence has greatly decreased in Europe and North America thanks to the use of conjugate vaccines (MenC and MenACWY) as well as the incidence of invasive disease due to serogroup A in sub-saharian Africa after the introduction of MenAfriVac conjugate vaccine. The great success of conjugate vaccines is related not only to the direct protection from disease but also to the impact on carriage; this latter allows an indirect protection of unimmunized subjects. For these reasons, the implementation of immunization with the new generation vaccines in the age classes most impacted by disease and carriage (first year of life, adolescence and young adulthood) could permit to achieve an extraordinary decrease of the incidence of meningococcal disease. PMID:26788731
Chretien, D; Gallego, J; Barrientos, A; Casademont, J; Cardellach, F; Munnich, A; Rötig, A; Rustin, P
1998-01-01
It is now widely acknowledged that a large number of human diseases originate from respiratory-chain dysfunctions. Because the molecular bases of these diseases are still poorly known, a biochemical approach has to be used in the screening procedures for the diagnoses of these conditions. Assessment of respiratory-chain function in human samples faces several problems: (i) the small size of available samples, (ii) the determination of discriminating parameters, and (iii) the interfering factors, such as age and physical activity. The present study focuses on isolated mitochondria prepared from a minute amount (100-200 mg) of skeletal-muscle biopsies from 201 patients between 0 and 65 years. Whereas 42 patients presented an isolated complex (C)I, CII, CIII or CIV deficiency, no respiratory-chain dysfunction or indirect evidence for a mitochondrial disorder could be attested in 159 of these patients. In this reference group, there was little correlation between enzyme activities and age, whatever the age class considered, 0-3 or 0-65 years of age. However, a confident handling of data points was largely hampered by the marked scattering of enzyme activities measured in the reference population. Activity ratios between the various respiratory-chain complexes presenting a much reduced scattering may be considered as diagnostic tools. As to the effect of age, no correlation with any of the enzyme-activity ratios could be shown. Use of age-matched controls for the diagnosis of respiratory-chain disorders may therefore be avoided, enzyme-activity ratios being highly discriminating and age-independent parameters. PMID:9425106
Aged boreal biomass-burning aerosol size distributions from BORTAS 2011
NASA Astrophysics Data System (ADS)
Sakamoto, K. M.; Allan, J. D.; Coe, H.; Taylor, J. W.; Duck, T. J.; Pierce, J. R.
2015-02-01
Biomass-burning aerosols contribute to aerosol radiative forcing on the climate system. The magnitude of this effect is partially determined by aerosol size distributions, which are functions of source fire characteristics (e.g. fuel type, MCE) and in-plume microphysical processing. The uncertainties in biomass-burning emission number-size distributions in climate model inventories lead to uncertainties in the CCN (cloud condensation nuclei) concentrations and forcing estimates derived from these models. The BORTAS-B (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellite) measurement campaign was designed to sample boreal biomass-burning outflow over eastern Canada in the summer of 2011. Using these BORTAS-B data, we implement plume criteria to isolate the characteristic size distribution of aged biomass-burning emissions (aged ~ 1-2 days) from boreal wildfires in northwestern Ontario. The composite median size distribution yields a single dominant accumulation mode with Dpm = 230 nm (number-median diameter) and σ = 1.5, which are comparable to literature values of other aged plumes of a similar type. The organic aerosol enhancement ratios (ΔOA / ΔCO) along the path of Flight b622 show values of 0.09-0.17 μg m-3 ppbv-1 (parts per billion by volume) with no significant trend with distance from the source. This lack of enhancement ratio increase/decrease with distance suggests no detectable net OA (organic aerosol) production/evaporation within the aged plume over the sampling period (plume age: 1-2 days), though it does not preclude OA production/loss at earlier stages. A Lagrangian microphysical model was used to determine an estimate of the freshly emitted size distribution corresponding to the BORTAS-B aged size distributions. The model was restricted to coagulation and dilution processes based on the insignificant net OA production/evaporation derived from the ΔOA / ΔCO enhancement ratios. We
NASA Astrophysics Data System (ADS)
Fadjie-Djomkam, A. B.; Ababou-Girard, S.; Godet, C.
2012-12-01
Electrical transport through molecular monolayers being very sensitive to disorder effects, admittance and current density characteristics of Hg//C12H25 - n Si junctions incorporating covalently bonded n-alkyl molecular layers, were investigated at low temperature (150-300 K), in the as-grafted state and after ageing at the ambient. This comparison reveals local oxidation effects both at the submicron scale in the effective barrier height distribution and at the molecular scale in the dipolar relaxation. In the bias range dominated by thermionic emission and modified by the tunnel barrier (TB) attenuation, exp(-β0dT), where dT is the thickness of the molecular tunnel barrier and β0 is the inverse attenuation length at zero applied bias, some excess current is attributed to a distribution of low barrier height patches. Complementary methods are used to analyze the current density J(V, T) characteristics of metal-insulator-semiconductor tunnel diodes. Assuming a Gaussian distribution of barrier heights centered at qΦB provides an analytical expression of the effective barrier height, qΦEFF(T)=qΦB+(kT)β0dT-(qδΦ)2/2kT; this allows fitting of the distribution standard deviation δΦ and tunnel parameter (β0dT) over a wide temperature range. In a more realistic modeling including the voltage dependence of barrier height and circular patch area, the so-called "pinch-off" effect is described by a distribution of parameter γ =3(ΔPRP2/4)1/3, which combines interface potential modulation and patch area variations. An arbitrary distribution of γ values, fitted to low-temperature J(V) data, is equally well described by Gaussian or exponential functions. Ageing in air also increases the interface oxidation of Si substrate and affects the density of localized states near mid gap, which typically rises to the high 1011 eV-1 cm-2 range, as compared with DS < 1011 eV-1 cm-2 in the as-grafted state. The bias-independent relaxation observed near 1 kHz at low temperature
Directional variations of mechanical parameters in rat skin depending on maturation and age.
Vogel, H G
1981-06-01
Mechanical properties of rat back skin at low loads and at failure were studied in 2 directions, e.g., perpendicular and longitudinal to body axis beginning with early maturation (from 1 week onwards) until senescence (at 24 mo). Anisotropic behavior, known for human skin, has also been found in rats. Surprisingly, the changes due to maturation and aging were not the same for one area of skin regardless of the direction. Ultimate extension was more influenced by the aging process in samples perpendicular to the body axis than in those parallel to body axis. Elongation at zero load, that means load not measurable under the described conditions, was higher in the longitudinal samples than in the perpendicular ones in young and very old animals, whereas this difference was absent in mature animals. In contrast, ultimate load, tensile strength and modulus of elasticity were higher in perpendicular samples than in samples longitudinal to the body axis for young and very old, but not for mature animals. Elongation at low loads or low stresses shows a different pattern than at medium loads or medium stresses when both directions are compared. Apparently, elements contributing to the mechanical properties in the various directions are differently influenced by the maturation and aging processes. Moreover, the elements contributing to the changes at low loads react differently to the aging process from those responsible for the effects at medium and high loads.
Locus of Control and Other Psycho-Social Parameters in Successful American Age-Group Swimmers.
ERIC Educational Resources Information Center
Burke, Edmund J., Jr.; Straub, William F.
Psycho-social factors in successful age-group swimmers were explored in this study. The subjects were 50 female and 39 male participants in the 1975 Amateur Athletic Union National Junior Olympics who were asked to answer a set of questions from an open-ended questionnaire. The results support a picture of young persons who invest a great deal of…
NASA Astrophysics Data System (ADS)
Smith, Russell J.; Lucey, John R.; Hudson, Michael J.
2009-12-01
We use high signal-to-noise spectroscopy for a sample of 232 quiescent galaxies in the Shapley supercluster, to investigate how their stellar populations depend on velocity dispersion (σ), luminosity and stellar mass. The sample spans a large range in velocity dispersion (30-300kms-1) and in luminosity (MR from -18.7 to -23.2). Estimates of age, total metallicity (Z/H) and α-element abundance ratio (α/Fe) were derived from absorption-line analysis, using single-burst models of Thomas and collaborators. Using the Rose CaII index, we conclude that recent star formation (frosting) events are not responsible for the intermediate ages observed in some of the galaxies. Age, Z/H and α/Fe are correlated positively with velocity dispersion, but we also find significant residual trends with luminosity: at given σ, the brighter galaxies are younger, less α-enriched and have higher Z/H. At face value, these results might suggest that the stellar populations depend on stellar mass as well as on velocity dispersion. However, we show that the observed trends can be reproduced by models in which the stellar populations depend systematically only on σ, and are independent of stellar mass M*. For age, the observed luminosity correlation arises because young galaxies are brighter, at fixed M*. For metallicity, the observed luminosity dependence arises because metal-rich galaxies, at fixed mass, tend also to be younger, and hence brighter. We find a good match to the observed luminosity correlations with age ~σ+0.40, Z/H~σ+0.35,α/Fe ~σ+0.20, where the slopes are close to those found when fitting traditional scaling relations. We conclude that the star formation and enrichment histories of galaxies are determined primarily by the depth of their gravitational potential wells. The observed residual correlations with luminosity do not imply a corresponding dependence on stellar mass.
NASA Astrophysics Data System (ADS)
Yao, Cheng; Li, Zhijia; Yu, Zhongbo; Zhang, Ke
2012-10-01
SummaryAn improved form of spatially distributed Grid-Xinanjiang model (GXM), which integrates features of a well-tested conceptual rainfall-runoff model and a physically based flow routing model, has been proposed for simulating hydrologic processes and forecasting flood events in watersheds. The digital elevation model (DEM) is utilized in the GXM to derive computational flow direction, routing sequencing, and hillslope and channel slopes. The processes in the model include canopy interception, direct channel precipitation, evapotranspiration, as well as runoff generation via a saturation excess mechanism. A two-step finite difference solution of the diffusion wave approximation of the St. Venant equations with second-order accuracy is used in the model to simulate the flow routed along the hillslope and channel on a cell basis with consideration of upstream inflow and flow partition to the channels. A physically, empirically based approach using geographically based information such as topography, soil data and land use/land cover data is employed for estimating spatially varied parameters. GXM is applied at a 1-km grid scale to a nested watershed located in Anhui province, China. The parent Tunxi watershed, with a drainage area of 2692.7 km2, contains five internal points with available observed streamflow data, allowing us to evaluate model's ability to simulate the hydrologic processes within the watershed. Calibration and verification of the proposed GXM are carried out for both daily and hourly time scales using daily rainfall-runoff data and hourly streamflow data. Model performance is assessed by comparing simulated and observed flows at the watershed outlet and interior gauging stations. Initial tests indicate that the parameter estimation approach is efficient and the developed model can satisfactorily simulate not only the streamflow at the parent watershed outlet, but also the flood hydrograph at the interior gauging points without model recalibration
Ortega, Ileana; Martín, Alberto; Díaz, Yusbelly
2011-03-01
Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataforma Deltana" section (0.007 +/- 0.022 ind/m2 in dry season and 0.014 +/- 0.06 ind/m2 in rainy season) and in the CFI project the densities in "Golfo de Paria" section were 0.705 +/- 0.829 ind/m2 in rainy season and 1.027 +/- 1.107 ind/m2 in dry season. The most frequent size range was 3.1-4.6cm. The highest biomass was found in "Golfo de Paria" section (7.581 +/- 0.018 mg/m2 in dry season and 0.005 +/- 6.542 x 10(-06) mg/m2 in rainy season for 2004-2005 and 3.979 +/- 4.024 mg/m2 in dry season; and 3.117 +/- 3.137 mg/m2 in rainy season for 2006). A linear relationship was found between the sea star size and its weight but no relationship was observed between its size and the depth where it was collected. Mollusks are dominant in the sea star diet (47.4% in abundance). The diet in any of the sections, seasons or between projects or size class was heterogeneous, using multivariate ordinations (MDS) and SIMPER analysis and there was no difference in the prey number or food elements that a sea star can eat. Although A
Ortega, Ileana; Martín, Alberto; Díaz, Yusbelly
2011-03-01
Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataforma Deltana" section (0.007 +/- 0.022 ind/m2 in dry season and 0.014 +/- 0.06 ind/m2 in rainy season) and in the CFI project the densities in "Golfo de Paria" section were 0.705 +/- 0.829 ind/m2 in rainy season and 1.027 +/- 1.107 ind/m2 in dry season. The most frequent size range was 3.1-4.6cm. The highest biomass was found in "Golfo de Paria" section (7.581 +/- 0.018 mg/m2 in dry season and 0.005 +/- 6.542 x 10(-06) mg/m2 in rainy season for 2004-2005 and 3.979 +/- 4.024 mg/m2 in dry season; and 3.117 +/- 3.137 mg/m2 in rainy season for 2006). A linear relationship was found between the sea star size and its weight but no relationship was observed between its size and the depth where it was collected. Mollusks are dominant in the sea star diet (47.4% in abundance). The diet in any of the sections, seasons or between projects or size class was heterogeneous, using multivariate ordinations (MDS) and SIMPER analysis and there was no difference in the prey number or food elements that a sea star can eat. Although A
Behavioral responses to and brain distribution of morphine in mature adult and aged mice
Burton, C.K.; Ho, I.K.; Hoskins, B.
1986-03-01
Mature adult (3-6 mo old) and aged (2 yr old) male ICR mice were injected with 10 to 100 mg/kg morphine, s.c. The ED50 values for running behavior (as measured using Stoelting activity monitors and having each mouse serve as its own control) representing 5 times control activity was approximately 7.5 mg/kg for aged mice and approximately 17.5 mg/kg for the mature adults. The ED50 values for analgesia 1 hr after morphine administration using the tail-flick method (max. response time = 8 sec) were approx. 70 mg/kg for the aged mice and 15 mg/kg for the mature adults. One hour after injecting /sup 3/H-morphine at doses of 30 and 100 mg/kg, 0.13 and 0.14% of the doses appeared in brains of aged and mature adult mice, respectively. Regional distribution of the morphine was the same for both age groups. Expressed as percent of total brain morphine, it was as follows: cortex, 30%; midbrain, 18%; cerebellum, 17%; medulla, 12%; pons, 9%; striatum, 8% and periaqueductal gray, 6%. Expressed as g morphine/g tissue for the 2 doses, the distribution was; periaqueductal gray, 30 and 80; striatum, 9 and 34; medulla, 6 and 20 pons; 5 and 19; cerebellum, 4 and 13; midbrain 2.5 and 8.5 and cortex, 2 and 8. These results suggest that the differences in response to morphine by the two age groups were due to age-related differences in opioid receptor populations and/or affinities.
Spatial and temporal simulation of groundwater age distributions of a small mountainous catchment
NASA Astrophysics Data System (ADS)
Gundel, Anita; Weiler, Markus; Schirmer, Mario
2013-04-01
The spatial and temporal storage characteristics of catchments are relevant to identify the vulnerability of catchments to climate change. Areas with high mean groundwater ages imply long residence times of water particles in the aquifer and are therefore a good indicator for high storage capacity of a catchment. Groundwater age in general is strongly influenced by porosity, flow direction and flow velocity. Hence, the great challenge for moutainous catchments is the steep topography and the complex geology which has the greatest impact on the groundwater age distribution. The main purpose of this study is the simulation of the groundwater age of a well-instrumented pre-alpine catchment in time and space to identify storage characteristics. One possibility to simulate groundwater age distributions in space and time is the application of a numerical groundwater model, which takes into account complex geological structures as well as the flow and transport processes of the unsaturated and saturated zone. In our study, we used the numerical 3D-finite-element groundwater flow and transport model FEFLOW with a transient direct mean age simulation method based on a mass-weighted average age. The study catchment Rietholzbach is located in the north-east of Switzerland, for which an adequate data set of discharge, groundwater level, and isotopic composition of the groundwater and stream water exists. First of all, a steady-state groundwater flow model was developed to validate the stability and accuracy of the flow simulation and model structure. Secondly, the steady-state results provide the initial conditions for the transient flow and transport simulation of the groundwater age distribution. Residence time simulations of this model were benchmarked against the stable isotope signal δ18O of groundwater and discharge. The results show that less water is stored along the creek in the shallow aquifer (young water) whereas substantial storage capacities (old water) are
Udhayakumar, Radhagayathri K; Karmakar, Chandan; Peng Li; Palaniswami, Marimuthu
2015-01-01
Complexity analysis of a given time series is executed using various measures of irregularity, the most commonly used being Approximate entropy (ApEn), Sample entropy (SampEn) and Fuzzy entropy (FuzzyEn). However, the dependence of these measures on the critical parameter of tolerance `r' leads to precarious results, owing to random selections of r. Attempts to eliminate the use of r in entropy calculations introduced a new measure of entropy namely distribution entropy (DistEn) based on the empirical probability distribution function (ePDF). DistEn completely avoids the use of a variance dependent parameter like r and replaces it by a parameter M, which corresponds to the number of bins used in the histogram to calculate it. When tested for synthetic data, M has been observed to produce a minimal effect on DistEn as compared to the effect of r on other entropy measures. Also, DistEn is said to be relatively stable with data length (N) variations, as far as synthetic data is concerned. However, these claims have not been analyzed for physiological data. Our study evaluates the effect of data length N and bin number M on the performance of DistEn using both synthetic and physiologic time series data. Synthetic logistic data of `Periodic' and `Chaotic' levels of complexity and 40 RR interval time series belonging to two groups of healthy aging population (young and elderly) have been used for the analysis. The stability and consistency of DistEn as a complexity measure as well as a classifier have been studied. Experiments prove that the parameters N and M are more influential in deciding the efficacy of DistEn performance in the case of physiologic data than synthetic data. Therefore, a generalized random selection of M for a given data length N may not always be an appropriate combination to yield good performance of DistEn for physiologic data.
Brambilla, Mattia; Ficetola, Gentile F
2012-07-01
1. Correlative species distribution models (SDMs) assess relationships between species distribution data and environmental features, to evaluate the environmental suitability (ES) of a given area for a species, by providing a measure of the probability of presence. If the output of SDMs represents the relationships between habitat features and species performance well, SDM results can be related also to other key parameters of populations, including reproductive parameters. To test this hypothesis, we evaluated whether SDM results can be used as a proxy of reproductive parameters (breeding output, territory size) in red-backed shrikes (Lanius collurio). 2. The distribution of 726 shrike territories in Northern Italy was obtained through multiple focused surveys; for a subset of pairs, we also measured territory area and number of fledged juveniles. We used Maximum Entropy modelling to build a SDM on the basis of territory distribution. We used generalized least squares and spatial generalized mixed models to relate territory size and number of fledged juveniles to SDM suitability, while controlling for spatial autocorrelation. 3. Species distribution models predicted shrike distribution very well. Territory size was negatively related to suitability estimated through SDM, while the number of fledglings significantly increased with the suitability of the territory. This was true also when SDM was built using only spatially and temporally independent data. 4. Results show a clear relationship between ES estimated through presence-only SDMs and two key parameters related to species' reproduction, suggesting that suitability estimated by SDM, and habitat quality determining reproduction parameters in our model system, are correlated. Our study shows the potential use of SDMs to infer important fitness parameters; this information can have great importance in management and conservation.
Pre-atmospheric parameters and fragment distribution: Case study for the Kosice meteoroid
NASA Astrophysics Data System (ADS)
Gritsevich, M.; Vinnikov, V.; Kuznetsova, D.; Kohout, T.; Pupyrev, Y.; Peltoniemi, J.; Tóth, J.; Britt, D.; Turchak, L.; Virtanen, J.
2014-07-01
We present results on our investigation on the Košice meteorite --- one of the recent falls with a well-derived trajectory and large number of recovered fragments. A fireball appeared over central-eastern Slovakia on February 28, 2010. The bolide reached an absolute magnitude of at least -18, enabling radiometers of the European Fireball Network to track the fireball despite the cloudy and rainy weather. The landing area was successfully computed on the basis of data from the surveillance cameras operating in Hungary and led to a fast meteorite recovery (Borovička et al. 2013). The first reported fragment of the meteorite was located northwest of the city of Košice in eastern Slovakia (Tóth et al. 2014). 218 fragments of the Košice meteorite, with a total mass of 11.285 kg, have been documented with almost 7 kg belonging to the collection of the Comenius University in Bratislava and Astronomical Institute of Slovak Academy of Sciences (Gritsevich et al. 2014). Based on the statistical investigation of the recovered fragments, bimodal Weibull, bimodal Grady, and bimodal lognormal distributions are found to be the most appropriate distributions for describing the Košice fragmentation process. The most probable scenario suggests that the Košice meteoroid, prior to further extensive fragmentation in the lower atmosphere, was initially represented by two independent pieces with cumulative residual masses of approximately 2 kg and 9 kg respectively (Gritsevich et al. 2014). About 1/3 of the recovered Košice fragments were thoroughly studied, including magnetic susceptibility, bulk and grain density measurements reported by Kohout et al. (2014). This analysis revealed that the Košice meteorites are H5 ordinary chondrites that originated from a homogenous parent meteoroid. To estimate the dynamic mass of the main fragment, we studied the first integral of the drag and mass-loss equations, and the geometrical relation along the meteor trajectory in the atmosphere
Ghanizadeh, Ghader; Mirmohamadlou, Ali; Esmaeli, Davoud
2016-09-01
Occurrence of Legionella pneumophila can be relevant to the installation age and the presence of heterotrophic plate counts (HPCs). This research illustrates L. pneumophila contamination of hospital water in accordance with the installation age and the presence of HPCs. One hundred and fifty samples were collected from hot and cold water systems and cultured on R2A and BCYE agar. L. pneumophila identification was done via specific biochemical tests. HPCs and L. pneumophila were detected in 96 and 37.3 % of the samples, respectively. The mean of HPCs density was 947 ± 998 CFU/ml; therefore, 52 % of the samples had higher densities than 500 CFU/ml. High densities of HPCs (>500 CFU/ml) led to colonization of L. pneumophila (≥1000 CFU/ml), mainly observed in cooling systems, gynecological, sonography, and NICU wards. Chi(2) test demonstrated that higher densities (>500 CFU/ml) of HPCs and L. pneumophila contamination in cold water were more frequent than warm water (OR: 2.3 and 1.49, respectively). Univariate regressions implied a significant difference between HPCs density and installation age in positive and negative tests of L. pneumophila (OR = 1.1, p < 0.001, OR = 1.2, p < 0.001). Mann-Whitney U test implied the significant effects of HPCs and installation age on L. pneumophila occurrences (p < 0.001). Spearman correlation and multivariate linear regression revealed significant differences between L. pneumophila and HPCs densities (r s = 0.33, p < 0.001 and ß = 0.11, p = 0.02), but nonsignificant difference with installation age (r s = 0.33, p < 0.001 and ß = 0.0, p = 0.91). The occurrence of L. pneumophila, HPCs, and installation age are relevant; so, plumbing system renovation with appropriate materials and promotion of the effective efforts for hospital's water quality assurance is highly recommended. PMID:27573071
NASA Astrophysics Data System (ADS)
Miyasato, Yoshihiko
The problem of constructing model reference adaptive H∞ control for distributed parameter systems of hyperbolic type preceded by unknown input nonlinearity such as dead zone or backlash, is considered in this paper. Distributed parameter systems are infinite dimensional processes, but the proposed control scheme is constructed from finite dimensional controllers. An adaptive inverse model is introduced to estimate and compensate the input nonlinearity. The stabilizing control signal is added to regulate the effect of spill-over terms, and it is derived as a solution of certain H∞ control problem where the residual part of the inverse model and the spill-over term are considered as external disturbances to the process.
NASA Astrophysics Data System (ADS)
Yang, Y.; Shen, F.; Feng, X.
2015-10-01
In this paper, we have developed an empirical model of the global distribution of plasma parameters on the coronal source surface (at 2.5 solar radii (Rs) in our study) by analyzing observations from Ulysses and OMNI data. We use this model to construct the global map of source surface plasma for four typical Carrington Rotations (CRs) during different phases of solar activity, and analyze the basic characteristics of the distribution. A simple validation of the model is made by comparing the density and velocity distribution with the pB-inversed density and Wang-Sheeley-Arge (WSA) model velocity. The preliminary results show that our model gives reasonable large scale distribution of source surface plasma parameters at different phases of solar activity.
Fisher, Leon; Srikusalanukul, Wichat; Fisher, Alexander; Smith, Paul
2015-01-01
Aim: To asses liver markers in older patients with hip fracture (HF) in relation to age, comorbidities, metabolic characteristics and short-term outcomes. Methods: In 294 patients with HF (mean age 82.0±7.9 years, 72.1% women) serum alanine aminotransferase (ALT), gammaglutamyltransferase (GGT), alkaline phosphatase (ALP), albumin, bilirubin, 25(OH)vitaminD, PTH, calcium, phosphate, magnesium, adiponectin, leptin, resistin, thyroid function and cardiac troponin I were measured. Results: Elevated ALT, GGT, ALP or bilirubin levels on admission were observed in 1.7% - 9.9% of patients. With age GGT, ALT and leptin decrease, while PTH and adiponectin concentrations increase. Higher GGT (>30U/L, median level) was associated with coronary artery disease (CAD), diabetes mellitus (DM), and alcohol overuse; lower ALT (≤20U/L, median level) with dementia; total bilirubin >20μmol/L with CAD and alcohol overuse; and albumin >33g/L with CAD. Multivariate adjusted regression analyses revealed ALT, ALP, adiponectin, alcohol overuse and DM as independent and significant determinants of GGT (as continuous or categorical variable); GGT for each other liver marker; and PTH for adiponectin. The risk of prolonged hospital stay (>20 days) was about two times higher in patients with GGT>30U/L or adiponectin >17.14 ng/L (median level) and 4.7 times higher if both conditions coexisted. The risk of in-hospital death was 3 times higher if albumin was <33g/L. Conclusions: In older HF patients liver markers even within the normal range are associated with age-related disorders and outcomes. Adiponectin (but not 25(OH)vitaminD, PTH, leptin or resistin) is an independent contributor to higher GGT. Serum GGT and albumin predict prolonged hospital stay and in-hospital death, respectively. A unifying hypothesis of the findings presented. PMID:25589886
Rosenkrantz, Walter A
2013-05-01
A method is given for computing simultaneous confidence intervals for order statistics obtained from a distribution depending on one or more parameters that must be estimated from the data. This produces a confidence band for the distribution itself and may be regarded as an extension of Kolmogorov's goodness-of-fit test to the case where the distribution depends on parameters that must be estimated from the data. The method works whenever the joint confidence set for the parameters is convex and the quantile function is linear in the parameters. Two special cases are treated in some detail: the normal and exponential distributions. Graphical representations and comparisons with results obtained by Lillifors and Stephens via Monte-Carlo methods are discussed. An unusual feature of this paper is that we found it necessary to first prove that the joint confidence set for the mean and variance for the normal distribution based on the Wald statistic is convex and compact. Our proof relies on an elementary theorem from differential geometry in the large due to Hopf and is of independent interest. PMID:23180516
Analyzing nutrient distribution in different particle-size municipal aged refuse.
Li, Guangke; Hou, Fen; Guo, Zhen; Yao, Gaoyi; Sang, Nan
2011-11-01
To investigate the feasibility of using aged municipal solid waste as farmland soil, it is essential to study its nutritive compositions for plant growth. Previous studies have demonstrated that the properties of different particle-size aged refuse are very different, therefore, the present study was conducted to evaluate the adequacy of three elements (N, P, K) and the fractionation of inorganic P in the aged refuse with a particle-size distribution of 900 to 300, 300 to 150, 150 to 105, 105 to 90 and 90 to 0 μm. The results indicate that (1) total quantities of N, P, K were much larger than that in the general soil and the quantities of available N, P and K were also adequate; (2) total content of P was sufficient, but the ratio of available-P to total P was not high enough; (3) with the decrease of particle size, the contents of these elements presented different trends. The results implicate that total contents of N, P and K were enough for the aged refuse being exploited as cultivated soil, and different gradation of aged refuse could be added to improve poor soils. It provides scientific evidence for utilizing different particle-size aged refuse comprehensively.
Sex and age differences in mercury distribution and excretion in methylmercury-administered mice
Hirayama, K.; Yasutake, A.
1986-01-01
Sex differences in mercury distribution and excretion after single administration of methylmercury chloride (MMC, 5 mg/kg were studied in mice. A sex difference in urinary mercury excretion was found in sexually mature mice (age of 7 wk) of C57BL/6N and BALB/cA strains. Males showed higher mercury levels in urine than females, though no significant difference was found in fecal mercury levels 24 h post exposure to MMC. The higher urinary excretion rates in males accounted for significant lowering of mercury levels in the brain, liver, and blood, but not in the kidney, which showed higher values. At 5 min, however, the sex difference was found only in the kidney, showing higher levels in males. Changes in mercury distribution with time were studied in C57BL/6N mice. The brain mercury increased in both sexes up to 3 d, and decreased only in males on d 5. Liver and blood mercury decreased with time in both sexes, and these were constantly higher in females than in males. Renal mercury in males decreased to similar levels to females on d 3. The sex differences at various ages were studied with C57BL/6N mice 24 h after dosing. Two-week-old mice did not show significant sex differences in the mercury distribution and excretion, and their urinary mercury levels were much lower as compared to the older mice. Urinary mercury excretion in both sexes increased at 4 wk of age and then decreased at 45 wk of age. At 4, 7, 10, and 45 wk of age, males showed higher urinary mercury levels than females. From these findings, it has been suggested that urinary mercury excretion may be related to sex hormones, especially androgens.
Age-related changes in endothelial permeability and distribution volume of albumin in rat aorta.
Belmin, J; Corman, B; Merval, R; Tedgui, A
1993-03-01
Age-related changes in macromolecular transport across the arterial wall were investigated in 10-, 20-, and 30-mo-old WAG/Rij rats. Animals were injected with 125I- and 131I-labeled albumin, 90 and 5 min before they were killed, respectively. The transmural distribution of relative concentration of tracers in the aortic wall was obtained using en face serial sectioning technique. The apparent endothelial permeability to albumin calculated from the distribution of 5-min 131I-labeled albumin concentrations was significantly enhanced in 20- and 30-mo-old rats compared with 10-mo-old rats. The apparent distribution volume of albumin within the media, estimated as the mean medial 125I-labeled albumin concentration, was not significantly changed in 20-mo-old rats but was significantly decreased in the 30-mo-old animals. These age-related changes in the macromolecular transport suggest that the entry of plasma macromolecules in the aged arterial wall might be enhanced, whereas the efflux through the media may be impeded, possibly contributing to their trapping in the subendothelium. PMID:8456970
Thompson, Robert S.; Anderson, Katherine H.; Strickland, Laura E.; Shafer, Sarah L.; Pelltier, Richard T.; Bartlein, Patrick J.
2006-01-01
Climate is the primary factor in controlling the continental-scale distribution of plant species, although the relations between climatic parameters and species' ranges is only now beginning to be quantified. Preceding volumes of this atlas explored the continental-scale relations between climatic parameters and the distributions of woody plant species across all of the continent of North America. This volume presents similar information for important woody species, groups of species, and ecoregions in more detail for the State of Alaska. For these analyses, we constructed a 25-kilometer equal-area grid of modern climatic and bioclimatic parameters for North America from instrumental weather records. We obtained a digital representation of the geographic distribution of each species or ecoregion, either from a published source or by digitizing the published distributions ourselves. The presence or absence of each species or ecoregion was then determined for each point on the 25-kilometer grid, thus providing a basis for comparison of the climatic data with the geographic distribution of each species or ecoregion. The relations between climate and these distributions are presented in graphical and tabular form.
Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.
Mettke-Hofmann, Claudia; Hamel, Paul B; Hofmann, Gerhard; Zenzal, Theodore J; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan; Greenberg, Russell
2015-01-01
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes.
Competition and Habitat Quality Influence Age and Sex Distribution in Wintering Rusty Blackbirds
Mettke-Hofmann, Claudia; Hamel, Paul B.; Hofmann, Gerhard; Zenzal Jr., Theodore J.; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan
2015-01-01
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes. PMID:25946335
Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.
Mettke-Hofmann, Claudia; Hamel, Paul B; Hofmann, Gerhard; Zenzal, Theodore J; Pellegrini, Anne; Malpass, Jennifer; Garfinkel, Megan; Schiff, Nathan; Greenberg, Russell
2015-01-01
Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes. PMID:25946335
NASA Technical Reports Server (NTRS)
Blodget, Herbert W.; Heirtzler, James R.
1993-01-01
Results are presented of an investigation to determine the degree to which digitally processed Landsat TM imagery can be used to discriminate among vegetated lava flows of different ages in the Menengai Caldera, Kenya. A selective series of five images, consisting of a color-coded Landsat 5 classification and four color composites, are compared with geologic maps. The most recent of more than 70 postcaldera flows within the caldera are trachytes, which are variably covered by shrubs and subsidiary grasses. Soil development evolves as a function of time, and as such supports a changing plant community. Progressively older flows exhibit the increasing dominance of grasses over bushes. The Landsat images correlated well with geologic maps, but the two mapped age classes could be further subdivided on the basis of different vegetation communities. It is concluded that field maps can be modified, and in some cases corrected by use of such imagery, and that digitally enhanced Landsat imagery can be a useful aid to field mapping in similar terrains.
Mendoza, F J; Estepa, J C; Gonzalez-De Cara, C A; Aguilera-Aguilera, R; Toribio, R E; Perez-Ecija, A
2015-05-01
Donkeys are commonly afflicted by endocrine and metabolic disturbances but few studies have investigated endocrine variables involved in energy regulation and their association with morphometric indices, age or gender in this species. Hemostatic and clinical differences have been demonstrated between horses and donkeys, so to consider both species as metabolically and endocrinologically similar could lead to misdiagnosis. In this study, plasma concentrations of glucose, triglycerides and endocrine factors involved in energy homeostasis (insulin, glucagon, leptin, adiponectin, ghrelin and insulin-like growth factor [IGF]-1) were measured and their association with morphometric variables (body condition score, neck scoring and body mass index), gender and age was determined in 62 healthy donkeys. In addition, a neck scoring system specific for donkeys was developed. Insulin, glucagon, leptin and IGF-1 concentrations were found to be similar between donkeys and other species, but adiponectin and active ghrelin were lower in donkeys than horses. Donkeys with larger neck scores and body mass indices had higher triglyceride, leptin and IGF-1 concentrations. A sexual dimorphism was observed on all morphometric measurements and plasma glucose concentrations independent of adiposity. Younger animals had lower morphometric measurements and triglyceride and leptin concentrations.
The U.S. EPA’s Technology Testing and Evaluation Program has been charged by EPA to evaluate the performance of commercially available water security-related technologies. Multi-parameter water monitors for distributions systems have been evaluated as such a water security techn...
Mapping post-disturbance stand age distribution in Siberian larch forest based on a novel method
NASA Astrophysics Data System (ADS)
Chen, D.; Loboda, T. V.; Krylov, A.; Potapov, P.
2014-12-01
The Siberian larch forest, which accounts for nearly 20% of the global boreal forest biome, is unique, important, yet significantly understudied. These deciduous needleleaf forests with a single species dominance over a large continuous area are not found anywhere except the extreme continental zones of Siberia and the Russian Far East. Most of these forests are located in remote and sparsely populated areas and, therefore, little is known about spatial variability of their structure and dynamics. Wall-to-wall repeated observations of this area are available only since the 2000s. Previously, we developed methods for reconstruction of stand-age distribution from a sample of 1980-2000 disturbances in Landsat TM and ETM+ imagery. However, availability of those images in Siberian larch forests is particularly limited. Built upon the hypothesis that the spectral characteristics of the disturbed forest in the region change with time consistently, this paper proposes a novel method utilizing the newly released Global Forest Change (GFC) 2000-2012 dataset. We exploit the data-rich era of annual forest disturbance samples identified between 2000 and 2012 in the Siberian larch forest by the GFC dataset to build a robust training set of spectral signatures from regrowing larch forests as they appear in Landsat imagery in 2012. The extracted statistics are ingested into a random forest, which predicts the approximate stand age for every forested pixel in the circa 2000 composite. After merging the estimated stand age distribution for 1989-2000 with the observed disturbance records for 2001-2012, a gap-free 30 m resolution 24-year long record of stand age distribution is obtained. A preliminary accuracy assessment against the Advanced Very High Resolution Radiometer (AVHRR) burned area product suggested satisfactory performance of the proposed method.
A General Approach for Specifying Informative Prior Distributions for PBPK Model Parameters
Characterization of uncertainty in model predictions is receiving more interest as more models are being used in applications that are critical to human health. For models in which parameters reflect biological characteristics, it is often possible to provide estimates of paramet...
Effects of age and its interaction with task parameters on lifting biomechanics.
Song, Jiahong; Qu, Xingda
2014-01-01
This study investigated the age-related differences in lifting biomechanics. Eleven younger and 12 older participants were instructed to perform symmetric lifting tasks defined by different combinations of destination heights and load magnitudes. Lifting biomechanics was assessed. It was found that the trunk flexion in the starting posture was 32% lower and the peak trunk extension velocity was 46% lower in older participants compared with those in younger ones, indicating that older adults tended to use safer lifting strategies than did younger adults. Based on these findings, we recommend that physical exercise programmes may be a more effective ergonomic intervention for reducing the risks of low back pain (LBP) in lifting among older workers, compared with instructions of safe lifting strategies. As for younger workers, instructions of safe lifting strategies would be effective in LBP risk reduction.
Mamaladze, M; Khutsishvili, L; Zarkua, E
2016-07-01
The current study aims at differentiating carious and/or non-carious diseases developed in Class 5 region and detecting the distribution rate at the age aspects. The study was conducted at the Dental Clinicand Educational-Research Center "Unident" LTD and Dental Clinic "Dens". 256 patients were involved in the study. All patients underwent a routine dental examination, while rentgenovisiography and CT were performed in case of need. For gathering the detailed medical history and integrated study of Class 5 defects, a special questionnaire/survey, providing detailed information on each patient, was developed. The conducted study revealed the following: The patients were divided into 3 age groups: 16-30 of ages (77 patients, I study group), 30-50 of ages (97 patients, II study group) and 50-70 of ages (82, III study group), respectively. In total 5802 teeth were examined. The subject of our interest was identification of intact and damaged teeth (affected with caries and non-carious diseases) in the above-mentioned contingent. It was found that carious disease of cervical zone of tooth (Class 5) most often was revealed in 30-50 age group (202 cases), which is 1.8-fold higher than the same index in the I study group (144) and 1.4-fold higher in the III study group (183), respectively; The highest rate of non-carious lesions (erosion, abrasion, abfraction) of dental neck was recorded in examined 50-70 age group (294 cases), which was 4.6 -fold higher than in the I study group (64) and 2.1 -fold higher in II study group (140), respectively; The lowest incidence of gingival recession was in the I study group (65 cases), which is 6.3 -fold lower than in the II study group (412) and 7.5-fold lower than - the III group (493). PMID:27661270
NASA Technical Reports Server (NTRS)
Ulbrich, C. W.; Atlas, D.
1977-01-01
A method of determining precipitation parameters from two remotely measurable quantities, the radar reflectivity factor and the optical extinction, is described. The raindrop size spectrum is approximated by a two-parameter exponential form; when these parameters are evaluated in terms of the radar reflectivity factor and the optical extinction, an exponential spectrum is obtained that is generally in very good agreement with the observed size spectrum. Other calculated precipitation parameters, such as rainfall rate and liquid water content, which are derived from the exponential approximation, also agree with experimental data. It is indicated that other combinations of two remote measurables can also be used to obtain more accurate estimates of precipitation parameters than can be obtained by the use of an empirical relationship.
Thompson, Robert S.; Anderson, Katherine H.; Pelltier, Richard T.; Shafer, Sarah L.; Bartlein, Patrick J.
2007-01-01
Climate is the primary factor controlling the continental-scale distribution of plant species, although the relations between climatic parameters and species' ranges are only now beginning to be quantified. This volume examines the relations between climate and the distributions of (1) Kuchler's 'potential natural vegetation' categories for the 48 contiguous States of the United States of America, (2) Bailey's ecoregions of North America, and (3) World Wildlife Fund's ecoregions of North America. For these analyses, we employed a 25-kilometer equal-area grid of modern climatic and bioclimatic parameters for North America, coupled with presence-absence data for the occurrence of each ecoregion under the three classification systems under consideration. The resulting relations between climate and ecoregion distributions are presented in graphical and tabular form. Presentation of ecoregion-climate relations here is intended to be useful for a greater understanding of ecosystem evolution, ecosystem dynamics, and potential effects of future climate change on ecoregions.
Differential Protein Distribution between the Nucleus and Mitochondria: Implications in Aging
Lionaki, Eirini; Gkikas, Ilias; Tavernarakis, Nektarios
2016-01-01
The coordination of nuclear and mitochondrial genomes plays a pivotal role in maintenance of mitochondrial biogenesis and functionality during stress and aging. Environmental and cellular inputs signal to nucleus and/or mitochondria to trigger interorganellar compensatory responses. Loss of this tightly orchestrated coordination results in loss of cellular homeostasis and underlies various pathologies and age-related diseases. Several signaling cascades that govern interorganellar communication have been revealed up to now, and have been classified as part of the anterograde (nucleus to mitochondria) or retrograde (mitochondrial to nucleus) response. Many of these molecular pathways rely on the dual distribution of nuclear or mitochondrial components under basal or stress conditions. These dually localized components usually engage in specific tasks in their primary organelle of function, whilst upon cellular stimuli, they appear in the other organelle where they engage in the same or a different task, triggering a compensatory stress response. In this review, we focus on protein factors distributed between the nucleus and mitochondria and activated to exert their functions upon basal or stress conditions. We further discuss implications of bi-organellar targeting in the context of aging.
Differential Protein Distribution between the Nucleus and Mitochondria: Implications in Aging
Lionaki, Eirini; Gkikas, Ilias; Tavernarakis, Nektarios
2016-01-01
The coordination of nuclear and mitochondrial genomes plays a pivotal role in maintenance of mitochondrial biogenesis and functionality during stress and aging. Environmental and cellular inputs signal to nucleus and/or mitochondria to trigger interorganellar compensatory responses. Loss of this tightly orchestrated coordination results in loss of cellular homeostasis and underlies various pathologies and age-related diseases. Several signaling cascades that govern interorganellar communication have been revealed up to now, and have been classified as part of the anterograde (nucleus to mitochondria) or retrograde (mitochondrial to nucleus) response. Many of these molecular pathways rely on the dual distribution of nuclear or mitochondrial components under basal or stress conditions. These dually localized components usually engage in specific tasks in their primary organelle of function, whilst upon cellular stimuli, they appear in the other organelle where they engage in the same or a different task, triggering a compensatory stress response. In this review, we focus on protein factors distributed between the nucleus and mitochondria and activated to exert their functions upon basal or stress conditions. We further discuss implications of bi-organellar targeting in the context of aging. PMID:27695477
Do predators influence the distribution of age-0 kokanee in a Colorado Reservoir?
Hardiman, J.M.; Johnson, B.M.; Martinez, P.J.
2004-01-01
Seasonal changes in reservoir conditions such as productivity, light, and temperature create spatiotemporal variation in habitat that may segregate or aggregate predators and prey, producing implications for the distribution, growth, and survival of fishes. We used hydroacoustics to document the diel vertical distribution of age-0 kokanee Oncorhynchus nerka relative to environmental gradients at Blue Mesa Reservoir, Colorado, during May-August of 2002. Temperature, light, and zooplankton density profiles were examined relative to foraging conditions for kokanee and their primary predator, lake trout Salvelinus namaycush. Age-0 kokanee displayed large diel vertical migrations in May despite the lack of an energetic advantage before reservoir stratification. Age-0 kokanee minimized near-surface foraging at this time, perhaps to avoid predation by visual predators, such as lake trout, in the well-lit surface waters. Strong reservoir stratification in midsummer appeared to provide a thermal refuge from lake trout that the kokanee exploited. By August vertical migrations were shallow and most kokanee remained in the epilimnion throughout the day. Although the energetic implications of the late-summer strategy are unclear, it appears that kokanee were responding to changes in their predator environment. A robust model for kokanee diel vertical migration across a range of systems should include a predator avoidance component.
Epigenetic contribution to age distribution of mortality within the Penna model.
Magdoń-Maksymowicz, M S; Maksymowicz, A Z
2015-06-01
Some modifications of the simple asexual Penna model, enriched by epigenetic contributions, are presented. The standard bit-string Penna model of biological aging and population evolution is based on an inherited DNA structure which defines the future life of a newly born individuals, when genes are activated by the biological clock, and the predefined genetic death is fully controlled by the number of defected genes. Epigenomes allow to introduce additional mechanism of gene activation or silencing without affecting the DNA genome itself. It may be either inherited or may reflect external, environmental factors. In the presented model, information read from the introduced epigenome may alter gene expression that may be stopped or re-activated. We concentrate on the influence of epigenetics on the age a distribution of genetic mortality m(a). Changes in m(a) are strong for the case of inherited epigenetic contribution with nearly perfect inheritance and 'positive' epigenome that partly ignores the 'bad' mutations. We conclude that the epigenetic contribution may influence population structure m(a) and could be, at least partly, responsible for deviation of m(a) distribution from the Gompertz law. In short, we claim that proposed epigenetic contribution may be seen as a candidate for possible explanation of observed deviation from the Gompertz law, also among senior members of society. A very simple model was used in this paper and many crucial mechanisms of biological aging were omitted. Therefore, further work based on a more realistic models is necessary. PMID:25666268
Webb, E.K.; Anderson, M.P. )
1991-03-01
A sedimentary deposition model, SEDSIM, was used to simulate the deposition of glaciofluvial sediments in south-central Wisconsin. These types of deposits are present at or near the surface over much of the northern United States and have a high contamination potential. They also represent relatively recent analogs for ancient braided stream systems. Sixty sediment samples were used to determine the average sediment properties for a facies assemblage located 8-10 km from the ice margin. A regional depositional system was simulated, using SEDSIM, to determine the range of input values that reproduced the observed average sediment characteristics. Progressively smaller scale models were constructed to produce more detailed estimates of the grain-size distribution. the grain-size estimates from the finest scale model were translated into relative hydraulic conductivity values using the method of Hazen. The resulting conductivities were incorporated into a fluid flow model to illustrate the control that heterogeneity of petrologic properties has on the direction and rate of fluid movement. This work indicates that a wide range of input parameters will reproduce the bulk sediment properties. Furthermore, small-scale features may not be reproduced under the assumptions incorporated in the current SEDSIM code. Thus, for sedimentary depositional models to be used to predict permeability and porosity distributions, or to interpret paleo-flow conditions, one must determine calibration targets that are more sensitive to flow parameters than bulk grain-size distributions.
Vatsalya, Vatsalya; Arora, Kashmiri L.
2014-01-01
The Japanese quail is a very valuable animal model for research in a variety of biological disciplines. The purpose of this study was to characterize and interrelate age-dependent testicular parameters with various blood constituents: blood glucose, plasma proteins and packed cell volume that are developing concurrently in the growing bird. Another objective of the study was to identify selective physioanatomical markers for predicting the testicular growth and the onset of sexual maturity. Male Japanese quail hatchlings were raised in temperature controlled brooders for up to 3 weeks of age under a constant light and then shifted to hanging cages in an air conditioned room set at ~73° F under a 14L: 10D lighting system and ad libitum access to feed and water. Starting d8, a group of 8–10 birds of uniform size and weight were selected randomly at 4-day intervals up to d52 of age for the project. The birds were weighed and blood sampled using the brachial vein and Blood Glucose (BGL), Total Plasma Proteins (PP) and Packed Cell Volume (PCV) levels were measured prior to euthanization. The testes were removed and measured for weight, length, width and Volume (VOL). All the testicular measurements were then correlated with age and body weight. The left testes were larger than the right testes and their differences were evident at d36 of age. Testicular measurements also reflected two distinct growth surges at d28, d32 and d36 of age. Combined Testes Weight (CTW) and Combined Testes Volume (CTV) revealed a strong positive correlation with PCV and PP and a negative correlation with Blood Glucose Level (BGL). Accordingly, these measurements could serve as reliable markers of growth rate and sexual maturation in male Japanese quail. PMID:25243007
Vatsalya, Vatsalya; Arora, Kashmiri L
2012-01-01
The Japanese quail is a very valuable animal model for research in a variety of biological disciplines. The purpose of this study was to characterize and interrelate age-dependent testicular parameters with various blood constituents: blood glucose, plasma proteins and packed cell volume that are developing concurrently in the growing bird. Another objective of the study was to identify selective physioanatomical markers for predicting the testicular growth and the onset of sexual maturity. Male Japanese quail hatchlings were raised in temperature controlled brooders for up to 3 weeks of age under a constant light and then shifted to hanging cages in an air conditioned room set at ~73° F under a 14L: 10D lighting system and ad libitum access to feed and water. Starting d8, a group of 8-10 birds of uniform size and weight were selected randomly at 4-day intervals up to d52 of age for the project. The birds were weighed and blood sampled using the brachial vein and Blood Glucose (BGL), Total Plasma Proteins (PP) and Packed Cell Volume (PCV) levels were measured prior to euthanization. The testes were removed and measured for weight, length, width and Volume (VOL). All the testicular measurements were then correlated with age and body weight. The left testes were larger than the right testes and their differences were evident at d36 of age. Testicular measurements also reflected two distinct growth surges at d28, d32 and d36 of age. Combined Testes Weight (CTW) and Combined Testes Volume (CTV) revealed a strong positive correlation with PCV and PP and a negative correlation with Blood Glucose Level (BGL). Accordingly, these measurements could serve as reliable markers of growth rate and sexual maturation in male Japanese quail.
Kwok, L Y; Wang, L; Zhang, J; Guo, Z; Zhang, H
2014-09-01
Ageing of the population is an imminent global problem. Lactobacillus casei Zhang (LcZ) was isolated from Inner Mongolian fermented milk, koumiss. LcZ possesses numerous probiotic properties in in vitro tests and in animal models. However, it has never been tested in any human trial. In the current study, the impact of oral consumption of LcZ on different age groups was tested. Chinese subjects, including 10 young, 7 middle-aged and 7 elderly volunteers (with mean age of 24.3, 47.6 and 64.7, respectively), were recruited. Each subject took 10.6 log10 cfu LcZ daily for a continuous period of 28 days. Several parameters, including the amounts of LcZ and four selected groups of bacteria, change of bacterial diversity, short chain fatty acids (SCFA) and total bile acids (TBA), were monitored in faecal samples collected from the subjects before starting, during and after stopping oral LcZ consumption. The consumption of LcZ exhibited beneficial effects to the subjects by modulating faecal microbiota in a temporal manner with a prolonged elevation of SCFA and reduction of TBA. The potentially harmful Pseudomonas and Acinetobacter genera were suppressed by the probiotic administration. Furthermore, a moderately divergent response was observed in the indigenous gut populations of Bifidobacterium and Bacteroides fragilis group in different age subjects. Taken together, the current study has provided proof on the positive effect of probiotic consumption and crucial insights into the design and application of probiotic-based products to users of different age segments. PMID:24854958
Bolte, M. )
1989-06-01
A differential comparison of precise CCD photometry in the globular clusters NGC 288, NGC 362, and NGC 1261 shows that differences exist in the positions of the main-sequence turnoff in these clusters that are most naturally explained if NGC 288 is some 3 billion yr older than NGC 362 and about 1 to 2 billion yr older than NGC 1261. This implies that the formation time for the Galactic halo is significantly longer than a freefall time. Consideration of the inferred ages and horizontal-branch morphologies of the clusters Pal 12, NGC 288, NGC 362, and NGC 1261, all with similar metal abundances, suggests that age may be the parameter that, after overall metal abundance, most determines horizontal-branch morphology. 56 refs.
NASA Astrophysics Data System (ADS)
Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng
2015-09-01
Gas distribution plays a significant role in an oxygen blast furnace. The uneven distribution of recycling gas from the shaft tuyere has been shown to affect the heat distribution and energy utilization in an oxygen blast furnace. Therefore, the optimal design and operating parameters beneficial to the gas distribution in an oxygen blast furnace should be determined. In total, three parameters and 22 different conditions in an oxygen blast furnace multifluid model were considered. The gas and heat distributions in an oxygen blast furnace under different conditions were simulated and compared. The study revealed that when the height of shaft tuyere decreased from 7.8 m to 3.8 m, the difference in top gas CO concentration between the center and edge decreased by 11.6%. When the recycling gas temperature increased from 1123 K to 1473 K, the difference in the top gas CO concentration between the center and edge decreased by 3.9%. As the allocation ratio increased from 0.90 to 1.94, the difference in the top gas CO concentration between the center and edge decreased by 3.0%. Considering both gas and heat distributions, a shaft tuyere height of 3.8 m to 4.8 m, a recycling gas temperature of 1473 K and an allocation ratio of 1.94 are recommended in practice under the conditions of this study.
NASA Astrophysics Data System (ADS)
Konar, B.; Ravelo, A.; Grebmeier, J.; Trefry, J. H.
2014-04-01
Epibenthic communities play a key role in ecosystem functioning in Arctic shelf Seas, such as in the Chukchi Sea in the Pacific Arctic. These communities, however, are patchily distributed and are influenced by various environmental parameters. Along with taxonomic composition, another community aspect that may vary spatially and be influenced by the environment is the distribution of organism sizes. This study presents the first size frequency distributions of nine epifaunal taxa that were determined to be dominant in the eastern Chukchi Sea in July/August 2009 and 2010, including male, female and gravid Chionoecetes opilio and Hyas coarctatus crabs, the gastropods Neptunea spp., Plicifusus spp., Colus spp., and Cryptonatica spp., and the echinoderms Gorgonocephalus spp., Leptasterias spp., and Echinarachnius parma. Some abundant taxa exhibited a wide range of sizes (i.e. C. opilio, Neptunea spp., and Leptasterias spp.), while others had a much smaller size range (i.e. Cryptonatica spp. and E. parma). We also found that size distributions of these taxa correlated with various combinations of the environmental parameters that have been shown to be important in structuring the general distribution patterns for the epibenthic invertebrate communities in the study area, including percent total sediment organic carbon, sediment chlorophyll a, temperature, latitude, sediment grain size 2 and 4 phi, pH, and dissolved oxygen. Our findings present benchmark information that is needed to detect future alterations in body-size frequency distributions that are likely to happen in response to the predicted climate and environmental changes in the Chukchi Sea region.
NASA Astrophysics Data System (ADS)
Xu, Bin; Kato, Toshiaki; Kaneko, Toshiro
2015-09-01
Single-walled carbon nanotubes (SWNTs) are promising materials in industry application, since they have many brilliant characteristics However, since the electronic and optical properties of SWNTs strongly depend on chirality, the selective synthesis of SWNTs with desired chiralities is one of the major challenges in nanotubes science and applications. In this study, time-controlled pulse plasma CVD has been developed aiming for the mass production of narrow chirality distributed SWNTs. Through the comparison of continuous plasma CVD and pulse plasma CVD, it is found that the amount of SWNTs can be increased in keeping with the initial narrow chirality distribution by repeating pulse plasma CVD. The effects of pulse time parameter, plasma off time, on the chirality distribution of SWNTs are also investigated. The chirality distribution becomes narrow with an increase in the plasma off time up to 60 sec, then it becomes broad with an increase in the off time. These indicate, adjustment of plasma time parameter in pulse plasma CVD can improve the uniformity of chirality distribution, resulting in the mass production of very narrow chirality distributed SWNTs. This work was supported by a Grant-in-Aid for JSPS Fellows Grant Number 15J01481.
Lee, J. H.; Lee, Y. M.; Oh, S.-H.; Son, H. J.; Jeong, D. J.; Whitley, Niki; Kim, J. J.
2014-01-01
The purpose of this study was to estimate genetic parameters of ultrasound measurements for longissimus dorsi muscle area (LMA), backfat thickness (BFT), and marbling score (MS) in Hanwoo cows (N = 3,062) at the ages between 18 and 42 months. Data were collected from 100 Hanwoo breeding farms in Gyeongbuk province, Korea, in 2007 and 2008. The cows were classified into four different age groups, i.e. 18 to 22 months (the first pregnancy period), 23 to 27 (the first parturition), 28 to 32 (the second pregnancy), and 33 to 42 (the second parturition), respectively. For each age group, a multi-trait animal model was used to estimate variance components and heritabilities of the three traits. The averages of LMA, BFT, and MS measurements across the cows of all age groups were 50.1 cm2, 4.62 mm, and 3.04, respectively and heritability estimates were 0.09, 0.10, and 0.08 for the respective traits. However, when the data were analyzed in different age groups, heritability estimates of LMA and BFT were 0.24 and 0.47, respectively, for the cows of 18 to 22 months of age, and 0.21 for MS in the 28 to 32 months old cows. When the cows of all age groups were used, the estimates of genetic (phenotypic) correlations were 0.43 (0.35), −0.06 (0.34) and 0.21 (0.32) between LMA and BFT, LMA and MS, and BFT and MS, respectively. However, in the cow age group between 28 and 32 (18 and 22) months, the estimates of genetic (phenotypic) correlations were 0.05 (0.29), −0.15 (0.24) and 0.38 (0.24), for the respective pairs of traits. These results suggest that genetic, environmental, and phenotypic variations differ depending on cow age, such that care must be taken when ultrasound measurements are applied to selection of cows for meat quality. PMID:25049938
Dormehl, Shilo J; Osborough, Conor D
2015-08-01
The aims of this study were to determine the effect of age, sex and race distance on velocity (v), stroke rate (SR), stroke length (SL) and stroke index (SI) of subelite adolescent swimmers in competition, and to investigate their pacing strategies during the 100-m and 200-m events. Video footage of 112 adolescent swimmers (56 female; 56 male), competing in the 100-m and 200-m freestyle events, in two age groups (12-14; 15-18 years) was recorded and subsequently analyzed. A MANOVA showed that all stroke parameters significantly differed between sexes and between race distances. The older adolescents had a higher v, a longer SL and a greater SI (p < .01) than the younger adolescents. There were significant interaction effects between age and sex for v, SL and SI. Most adolescents had a SL that was within 7% of that reported for 1992 Olympians, but had up to 16% lower SRs. Separate Friedman's ANOVAs showed that SL differed between successive race quarters for both age groups, both sexes and both race distances. It is likely that physical immaturity, inexperience in competition pacing and within-race fatigue strongly influence the performances of subelite adolescent front crawl swimmers. PMID:25902554
Dormehl, Shilo J; Osborough, Conor D
2015-08-01
The aims of this study were to determine the effect of age, sex and race distance on velocity (v), stroke rate (SR), stroke length (SL) and stroke index (SI) of subelite adolescent swimmers in competition, and to investigate their pacing strategies during the 100-m and 200-m events. Video footage of 112 adolescent swimmers (56 female; 56 male), competing in the 100-m and 200-m freestyle events, in two age groups (12-14; 15-18 years) was recorded and subsequently analyzed. A MANOVA showed that all stroke parameters significantly differed between sexes and between race distances. The older adolescents had a higher v, a longer SL and a greater SI (p < .01) than the younger adolescents. There were significant interaction effects between age and sex for v, SL and SI. Most adolescents had a SL that was within 7% of that reported for 1992 Olympians, but had up to 16% lower SRs. Separate Friedman's ANOVAs showed that SL differed between successive race quarters for both age groups, both sexes and both race distances. It is likely that physical immaturity, inexperience in competition pacing and within-race fatigue strongly influence the performances of subelite adolescent front crawl swimmers.
The Old Imbrium Hypothesis. [revision for KREEP materials formation age and distribution
NASA Technical Reports Server (NTRS)
Schonfeld, E.; Meyer, C., Jr.
1973-01-01
It is proposed that the order of lunar events was such that the Imbrium event predates the formation of the lunar rock type called KREEP. This hypothesis is used to explain the distribution of KREEP in the regions of Imbrium ejecta and the location of KREEP within the Imbrium and Procellarum mare regions. Model ages of KREEP materials have been previously interpreted to mean that their 'formation' age (time of initial extrusion) is about 4.3 to 4.4 AE. Consequently it is suggested that the Imbrium impact was before 4.3 to 4.4 AE rather than at about 3.9 AE, as is currently believed. This Old Imbrium Hypothesis is not yet proven, but seems to be consistent with a large variety of basic lunar observations.
Gender- and Age-Specific REE and REE/FFM Distributions in Healthy Chinese Adults
Cheng, Yu; Yang, Xue; Na, Li-Xin; Li, Ying; Sun, Chang-Hao
2016-01-01
Basic data on the resting energy expenditure (REE) of healthy populations are currently rare, especially for developing countries. The aims of the present study were to describe gender- and age-specific REE distributions and to evaluate the relationships among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. This cross-sectional survey included 540 subjects (343 women and 197 men, 20–79 years old). REE was measured by indirect calorimetry and expressed as kcal/day/kg total body weight. The data were presented as the means and percentiles for REE and the REE to fat-free mass (FFM) ratio; differences were described by gender and age. Partial correlation analysis was used to analyze the correlations between REE, tertiles of REE/FFM, and glycolipid metabolism and eating behaviors. In this study, we confirmed a decline in REE with age in women (p = 0.000) and men (p = 0.000), and we found that men have a higher REE (p = 0.000) and lower REE/FFM (p = 0.021) than women. Furthermore, we observed no associations among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. In conclusion, the results presented here may be useful to clinicians and nutritionists for comparing healthy and ill subjects and identifying changes in REE that are related to aging, malnutrition, and chronic diseases. PMID:27598192
Gender- and Age-Specific REE and REE/FFM Distributions in Healthy Chinese Adults.
Cheng, Yu; Yang, Xue; Na, Li-Xin; Li, Ying; Sun, Chang-Hao
2016-01-01
Basic data on the resting energy expenditure (REE) of healthy populations are currently rare, especially for developing countries. The aims of the present study were to describe gender- and age-specific REE distributions and to evaluate the relationships among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. This cross-sectional survey included 540 subjects (343 women and 197 men, 20-79 years old). REE was measured by indirect calorimetry and expressed as kcal/day/kg total body weight. The data were presented as the means and percentiles for REE and the REE to fat-free mass (FFM) ratio; differences were described by gender and age. Partial correlation analysis was used to analyze the correlations between REE, tertiles of REE/FFM, and glycolipid metabolism and eating behaviors. In this study, we confirmed a decline in REE with age in women (p = 0.000) and men (p = 0.000), and we found that men have a higher REE (p = 0.000) and lower REE/FFM (p = 0.021) than women. Furthermore, we observed no associations among glycolipid metabolism, eating behaviors, and REE in healthy Chinese adults. In conclusion, the results presented here may be useful to clinicians and nutritionists for comparing healthy and ill subjects and identifying changes in REE that are related to aging, malnutrition, and chronic diseases. PMID:27598192
Scala, R; Aronne, D; Palumbo, U; Montella, L; Giacobbe, R; Martucci, P; Del Prato, B
2000-04-01
The incidence of bronchiectasis (BCT) has probably decreased in developed countries in recent years, but reliable statistical data on its occurrence are still lacking. The aim of the present study was to retrospectively evaluate the prevalence, age distribution and aetiology of BCT, diagnosed in a selected series of symptomatic patients of a Western country by using bronchography. The authors analysed the main known predisposing and associated conditions (PACs), and the occurrence and age distribution of BCT in 144 consecutive patients who underwent bronchological examination (fibreoptic bronchoscopy and bronchography) in the years 1987-1994 because of recurrent purulent bronchitis and/or haemoptysis. The overall prevalence of BCT was 34% (49/144); its age distribution was: 17.2% (0-10 yrs), 43.7% (11-20 yrs), 38% (21-30 yrs), 37.5% (31-40 yrs), 33.3% (41-50 yrs), 40% (51-60 yrs), and 20% (61-70 yrs). Thirty-one PACs were found in 29/144 patients of the whole study group. The prevalence of BCT was significantly higher in the subgroup of 29 patients with PACs than in the subgroup of 115 patients without PACs (75.9% versus 23.5%; p < 0000001). The aetiology of BCT was mainly unexplained, as it was only possible to detect 24 PACs in 22/49 patients with BCT (44.9%): congenital, genetic and immune disorders (eight), localized airways obstructive diseases (five), pulmonary infections (three), bronchial asthma (two), pulmonary lobar fibrosis (two), ulcerative colitis (two), dermatomiositis (one), and toxin inhalation (one). The authors conclude that bronchiectasis still occurs in a large percentage of symptomatic patients of a developed country in the post-antimicrobial era, especially in the second to sixth decades, as well as in the presence of predisposing and associated conditions; its aetiology remains unknown in more than half of cases.
Wang, Shi-Wei; Pan, Cun-De
2012-09-01
By the methods of layered digging and image scanning analysis, this paper studied the root system spatial distribution of different aged Armeniaca vulgaris cv. Luntaibaixing in arid oasis under irrigation. The root system of A. vulgaris cv. Luntaibaixing was mainly constituted by fine roots (d < or = 1 mm), while medium roots (1
Wang, Shi-Wei; Pan, Cun-De
2012-09-01
By the methods of layered digging and image scanning analysis, this paper studied the root system spatial distribution of different aged Armeniaca vulgaris cv. Luntaibaixing in arid oasis under irrigation. The root system of A. vulgaris cv. Luntaibaixing was mainly constituted by fine roots (d < or = 1 mm), while medium roots (1
NASA Astrophysics Data System (ADS)
Laio, Francesco
2004-09-01
The use of goodness of fit tests based on Cramer-von Mises and Anderson-Darling statistics is discussed, with reference to the composite hypothesis that a sample of observations comes from a distribution, FH, whose parameters are unspecified. When this is the case, the critical region of the test has to be redetermined for each hypothetical distribution FH. To avoid this difficulty, a transformation is proposed that produces a new test statistic which is independent of FH. This transformation involves three coefficients that are determined using the asymptotic theory of tests based on the empirical distribution function. A single table of coefficients is thus sufficient for carrying out the test with different hypothetical distributions; a set of probability models of common use in extreme value analysis is considered here, including the following: extreme value 1 and 2, normal and lognormal, generalized extreme value, three-parameter gamma, and log-Pearson type 3, in all cases with parameters estimated using maximum likelihood. Monte Carlo simulations are used to determine small sample corrections and to assess the power of the tests compared to alternative approaches.
Matthey, Renaud; Affolderbach, Christoph; Mileti, Gaetano
2011-09-01
Distributed-feedback laser diodes emitting at 780 nm have been evaluated, with respect to the aging of the injection current required for reaching the rubidium D2 resonance line. Results obtained for lasers operating in air and in vacuum for 9 months are reported. When operated at constant temperature, the laser current required for emission at the wavelength of the desired atomic resonance is found to decrease by 50 to 80 μA per month. The impact of this result on the lifetime and long-term performances of laser-pumped rubidium atomic clocks is discussed.
The galactic habitable zone and the age distribution of complex life in the Milky Way.
Lineweaver, Charles H; Fenner, Yeshe; Gibson, Brad K
2004-01-01
We modeled the evolution of the Milky Way Galaxy to trace the distribution in space and time of four prerequisites for complex life: the presence of a host star, enough heavy elements to form terrestrial planets, sufficient time for biological evolution, and an environment free of life-extinguishing supernovae. We identified the Galactic habitable zone (GHZ) as an annular region between 7 and 9 kiloparsecs from the Galactic center that widens with time and is composed of stars that formed between 8 and 4 billion years ago. This GHZ yields an age distribution for the complex life that may inhabit our Galaxy. We found that 75% of the stars in the GHZ are older than the Sun.
Determine the Dose Distribution Using Ultrasound Parameters in MAGIC-f Polymer Gels.
Masoumi, Hossein; Mokhtari-Dizaji, Manijhe; Arbabi, Azim; Bakhshandeh, Mohsen
2016-01-01
In this study, using methacrylic and ascorbic acid in gelatin initiated by copper (MAGIC-f) polymer gel after megavoltage energy exposure, the sensitivity of the ultrasound velocity and attenuation coefficient dose-dependent parameters was evaluated. The MAGIC-f polymer gel was irradiated under 1.25 MeV cobalt-60, ranging from 0 to 60 Gy in 2-Gy steps, and received dose uniformity and accuracy of ±2%. After calibration of the ultrasonic systems with a frequency of 500 kHz, the parameters of ultrasound velocity and attenuation coefficient of the irradiated gel samples were measured. According to the dose-response curve, the ability of ultrasonic parameters was evaluated in dose rate readings. Based on a 4-order polynomial curve, fitted on the dose-response parameters of ultrasound velocity and attenuation coefficient and observed at 24 hours after irradiation, ultrasonic parameters had more sensitivity. The sensitivity of the dose-velocity and dose-attenuation coefficient curves was observed as 50 m/s/Gy and 0.06 dB/MHz/Gy over the linear range of 4 to 44 Gy, respectively. The ultrasonic parameters at 5°C, 15°C, and 25°C on the gel dosimeter after 0 to 60 Gy irradiation showed that readings at 25°C have higher sensitivity compared to 15°C and 5°C. Maximum sensitivity time and temperature readings of the MAGIC-f ultrasonic parameters were concluded 24 hours after irradiation and at a temperature of 25°C.
NASA Astrophysics Data System (ADS)
Christiaens, K.; Feyen, J.
2002-02-01
Both calibration and uncertainty assessment are mandatory steps in today's modelling process. The former considers both the inputs (input variables and parameters) as well as model results. An exploratory investigation of the applicable parameter space results in a wide spectrum of values for a specific model output. By retaining only those model realizations that mimic reality in a sufficient way, inputs and associated response can be constrained, thereby quantifying the uncertainty involved. The generalized likelihood uncertainty estimation (GLUE) framework provides a structured methodology for this purpose.The study presented focuses on the applicability of the GLUE framework within the context of the distributed hydrological model MIKE SHE. Even though all significant processes involved are incorporated within the model, the problems of calibration and uncertainty assessment cannot be avoided. This has resulted in a quest for well-delineated effective parameters crucial for sound mechanistic model application. Being a complex model, the number of possible realizations using MIKE SHE is fairly small due to computing time, and an in-depth exploratory approach is impossible. On the other hand, several output variables are available aside from the hydrological river response, like water content in the soil profile or ground water level, which can be used for retaining realistic parameter sets.This study presents some preliminary results on the applicability of the GLUE-MIKE SHE framework and associated constrained preliminary parameter and output uncertainty values. Focus was given to the influence of soil hydraulic parameters on the hydrological behaviour of a small study basin. The soil hydraulic parameters were predicted using various pedo-transfer-function approaches and moisture retention measurements in the laboratory, and these distributions were then confronted with ranges of the constrained effective parameters. For the latter, the restrictions that were
NASA Astrophysics Data System (ADS)
Edmonds, C. S.; Gratus, J.; Hock, K. M.; Machida, S.; Muratori, B. D.; Torromé, R. G.; Wolski, A.
2014-05-01
In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA.
Distributed parameter estimation in unreliable sensor networks via broadcast gossip algorithms.
Wang, Huiwei; Liao, Xiaofeng; Wang, Zidong; Huang, Tingwen; Chen, Guo
2016-01-01
In this paper, we present an asynchronous algorithm to estimate the unknown parameter under an unreliable network which allows new sensors to join and old sensors to leave, and can tolerate link failures. Each sensor has access to partially informative measurements when it is awakened. In addition, the proposed algorithm can avoid the interference among messages and effectively reduce the accumulated measurement and quantization errors. Based on the theory of stochastic approximation, we prove that our proposed algorithm almost surely converges to the unknown parameter. Finally, we present a numerical example to assess the performance and the communication cost of the algorithm.
Khormi, Hassan M; Kumar, Lalit
2011-10-15
Dengue fever (DF) and its impacts are growing environmental, economic, and health concerns in Saudi Arabia. In this study, we have attempted to model areas with humans at risk of dengue fever prevalence, depending on the spatial relationship between dengue fever cases and different socioeconomic parameters. We have developed new methods to verify the quality of neighborhoods from high resolution satellite images based on several factors such as density of houses in each neighborhood in each district, width of streets, and roof area of houses. In the absence of detailed neighborhood quality information being available for each district, we felt this factor would best approximate the reality on the ground at local scales. Socioeconomic parameters, such as population numbers, population density, and neighborhood quality were analyzed using Geographically Weighted Regression (GWR) to create a prediction model identifying levels of risk of dengue and to describe the association between DF cases and the related socio-economic factors. Descriptive analysis was used to characterize dengue fever victims among Saudis and non-Saudis in various age groups. The results show that there was a strong positive association between dengue fever cases and socioeconomic factors (R²=0.80). The prevalence among Saudis was higher compared to non-Saudis in 2006 and 2007, while the prevalence among non-Saudis was higher in 2008, 2009 and 2010. For age groups, DF was more prevalent in adults between the ages of 16 and 60, accounting for approximately 74% of all reported cases in 2006, 67% in 2007, 81% in 2008, 87% in 2009, and 81% in 2010.
Model-independent constraints on the shape parameters of dilepton angular distributions
NASA Astrophysics Data System (ADS)
Faccioli, Pietro; Lourenço, Carlos; Seixas, João; Wöhri, Hermine K.
2011-03-01
The coefficients determining the dilepton decay angular distribution of vector particles obey certain positivity constraints and a rotation-invariant identity. These relations are a direct consequence of the covariance properties of angular momentum eigenstates and are independent of the production mechanism. The Lam-Tung relation can be derived as a particular case, simply recognizing that the Drell-Yan dilepton is always produced transversely polarized with respect to one or more quantization axes. The dilepton angular distribution continues to be characterized by a frame-independent identity also when the Lam-Tung relation is violated. Moreover, the violation can be easily characterized by measuring a one-dimensional distribution depending on one shape coefficient.
On-Line Water Quality Parameters as Indicators of Distribution System Contamination
At a time when the safety and security of services we have typically taken for granted are under question, a real-time or near real-time method of monitoring changes in water quality parameters could provide a critical line of defense in protecting public health. This study was u...
Effect of backpack position on foot weight distribution of school-aged children
Kim, Kyung; Kim, Chang Ju; Oh, Duck-Won
2015-01-01
[Purpose] In the present study, we aimed to determine the effects of backpack position on foot weight distribution of standing school-aged children. [Subjects] Thirty school-aged children volunteered to participate in this study. [Methods] The subjects randomly performed four types of carrying a backpack: no backpack (condition-1), carrying a backpack at C7 (condition-2), carrying a backpack at 10 cm below C7 (condition-3), and carrying a backpack at 20 cm below C7 (condition-4). [Results] Statistically significant differences were noted in the anterior and posterior pressure values, and in the anterior-to-posterior ratio, among the four conditions (p < 0.05). Post-hoc analysis indicated that the pressure value of condition-4 was significantly lower in the anterior foot region and higher in the posterior foot region than in condition-2 and condition-3. In addition, the anterior-to-posterior ratio was lower in condition-4 than in condition-2 and condition-3. [Conclusion] These findings suggest that carrying a backpack in a higher position, with fastening of the shoulder strap, may be more favorable for normalizing the foot weight distribution. PMID:25931722
Effect of backpack position on foot weight distribution of school-aged children.
Kim, Kyung; Kim, Chang Ju; Oh, Duck-Won
2015-03-01
[Purpose] In the present study, we aimed to determine the effects of backpack position on foot weight distribution of standing school-aged children. [Subjects] Thirty school-aged children volunteered to participate in this study. [Methods] The subjects randomly performed four types of carrying a backpack: no backpack (condition-1), carrying a backpack at C7 (condition-2), carrying a backpack at 10 cm below C7 (condition-3), and carrying a backpack at 20 cm below C7 (condition-4). [Results] Statistically significant differences were noted in the anterior and posterior pressure values, and in the anterior-to-posterior ratio, among the four conditions (p < 0.05). Post-hoc analysis indicated that the pressure value of condition-4 was significantly lower in the anterior foot region and higher in the posterior foot region than in condition-2 and condition-3. In addition, the anterior-to-posterior ratio was lower in condition-4 than in condition-2 and condition-3. [Conclusion] These findings suggest that carrying a backpack in a higher position, with fastening of the shoulder strap, may be more favorable for normalizing the foot weight distribution. PMID:25931722
NASA Technical Reports Server (NTRS)
Davies, A. G.
2003-01-01
A high-spatial-resolution, multi-wavelength observation by the Galileo NIMS instrument has been analysed to determine the temperature and area distribution of a large portion of the ionian volcano Loki Patera. The temperatures of the cooler components from a two-temperature fit to the data can be used to determine ages of the surface. The age of the floor along a profile across the floor of the caldera ranges from 10 to 80 days. This puts the start of the resurfacing in July/early August 2001, yielding a resurfacing rate of approximately 1 km/day, with the new lava spreading from the SW corner of the caldera in a NE direction. This rate is consistent with resurfacing by foundering of the crust on a lava lake. However,the temperature distribution may also result from the emplacement of flows. Implied crust thicknesses (derived using a lava cooling model) range from 2.6 to 0.9 m.
NASA Astrophysics Data System (ADS)
Merdan, Ziya; Karakuş, Özlem
2016-07-01
The six dimensional Ising model with nearest-neighbor pair interactions has been simulated and verified numerically on the Creutz Cellular Automaton by using five bit demons near the infinite-lattice critical temperature with the linear dimensions L=4,6,8,10. The order parameter probability distribution for six dimensional Ising model has been calculated at the critical temperature. The constants of the analytical function have been estimated by fitting to probability function obtained numerically at the finite size critical point.
Distribution pattern and the risks of OPCs, PHAs and PCBs in aged refuses from landfill.
Lou, Ziyang; Li, Anding; Tai, Jun; Yuan, Wenxiang; Zhu, Nanwen; Zhao, Youcai
2016-09-01
Persistent organic pollutants (POPs) are the urgent risk for landfill, and should be considered before the landfill reclamation and resource. In this work, the distribution pattern of selected POPs in landfill and their ecological risks were investigated and assessed. The Σ20OCPs, Σ16PAHs and Σ19PCBs were around 157.4-329.2, 4103-19,190, and 79.1-340.3μgkg(-1) in aged refuses, with the mean value of 206.6, 8645.4, and 155.1μgkg(-1). While those in soil covers were only 6.3-75.4, 125.5-515.3 and 2.6-43.4μgkg(-1), with the mean value of 33.7, 257.7, and 24.0μgkg(-1), respectively. The maximum OPCs, PHAs and PCBs were in aged refuse with 13, 7, 10 disposal years. Whereas, the corresponding top content in soil covers were in 10, 13 and 16years, meaning that aged refuses were not the direct source for soil covers. Among 20 OCPs measured, α-HCH, δ-HCH, Dieldrin, and Endrin were presented in all aged refuses, with the mean concentration of 93.6, 52.1, 3.9 and 4.7μgkg(-1), respectively. For PAHs, PHE, FLU and PYR were the main composition, and reached to 1535, 1224, 1187μgkg(-1). The Σ7CarPAHs occupied around 33.3-49.9% of total Σ16PAHs tested, and could be used as the indictor for PAHs pollutant in landfill. PCB-5 content was around 40.7-263.3μgkg(-1) in aged refuses, and occupied around 51.5-81.8% of Σ19PCBs measured. The HCHs and DDTs in aged refuses were below the national standard GB15618-1995, and the corresponding Σ19PCBs concentrations met the standard of GB 13015-91, suggesting that aged refuse are accepted for the further utilization process. PMID:26994555
A mitochondrial location for haemoglobins--dynamic distribution in ageing and Parkinson's disease.
Shephard, Freya; Greville-Heygate, Oliver; Marsh, Oliver; Anderson, Susan; Chakrabarti, Lisa
2014-01-01
Haemoglobins are iron-containing proteins that transport oxygen in the blood of most vertebrates. The mitochondrion is the cellular organelle which consumes oxygen in order to synthesise ATP. Mitochondrial dysfunction is implicated in neurodegeneration and ageing. We find that α and β haemoglobin (Hba and Hbb) proteins are altered in their distribution in mitochondrial fractions from degenerating brain. We demonstrate that both Hba and Hbb are co-localised with the mitochondrion in mammalian brain. The precise localisation of the Hbs is within the inner membrane space and associated with inner mitochondrial membrane. Relative mitochondrial to cytoplasmic ratios of Hba and Hbb show changing distributions of these proteins during the process of neurodegeneration in the pcd(5j) mouse brain. A significant difference in mitochondrial Hba and Hbb content in the mitochondrial fraction is seen at 31 days after birth, this corresponds to a stage when dynamic neuronal loss is measured to be greatest in the Purkinje Cell Degeneration mouse. We also report changes in mitochondrial Hba and Hbb levels in ageing brain and muscle. Significant differences in mitochondrial Hba and Hbb can be seen when comparing aged brain to muscle, suggesting tissue specific functions of these proteins in the mitochondrion. In muscle there are significant differences between Hba levels in old and young mitochondria. To understand whether the changes detected in mitochondrial Hbs are of clinical significance, we examined Parkinson's disease brain, immunohistochemistry studies suggest that cell bodies in the substantia nigra accumulate mitochondrial Hb. However, western blotting of mitochondrial fractions from PD and control brains indicates significantly less Hb in PD brain mitochondria. One explanation could be a specific loss of cells containing mitochondria loaded with Hb proteins. Our study opens the door to an examination of the role of Hb function, within the context of the mitochondrion
Ages, distributions, and origins of upland coastal dune sheets in Oregon, USA
Peterson, C.D.; Stock, E.; Price, D.M.; Hart, R.; Reckendorf, F.; Erlandson, J.M.; Hostetler, S.W.
2007-01-01
A total of ten upland dune sheets, totaling 245??km in combined length, have been investigated for their origin(s) along the Oregon coast (500??km in length). The ages of dune emplacement range from 0.1 to 103??ka based on radiocarbon (36 samples) and luminescence (46 samples) dating techniques. The majority of the emplacement dates fall into two periods of late-Pleistocene age (11-103??ka) and mid-late-Holocene age (0.1-8??ka) that correspond to marine low-stand and marine high-stand conditions, respectively. The distribution of both the late-Pleistocene dune sheets (516??km2 total surface area) and the late-Holocene dune sheets (184??km2) are concentrated (90% of total surface area) along a 100??km coastal reach of the south-central Oregon coast. This coastal reach lies directly landward of a major bight (Heceta-Perpetua-Stonewall Banks) on the continental shelf, at depths of 30-200??m below present mean sea level (MSL). The banks served to trap northward littoral drift during most of the late-Pleistocene conditions of lowered sea level (- 50 ?? 20??m MSL). The emerged inner-shelf permitted cross-shelf, eolian sand transport (10-50??km distance) by onshore winds. The depocenter sand deposits were reworked by the Holocene marine transgression and carried landward by asymmetric wave transport during early- to mid-Holocene time. The earliest dated onset of Holocene dune accretion occurred at 8??ka in the central Oregon coast. A northward migration of Northeast Pacific storm tracks to the latitude of the shelf depocenter (Stonewall, Perpetua, Heceta Banks) in Holocene time resulted in eastward wave transport from the offshore depocenter. The complex interplay of coastal morphology, paleosea-level, and paleoclimate yielded the observed peak distribution of beach and dune sand observed along the south-central Oregon coast. ?? 2007 Elsevier B.V. All rights reserved.
Aging affects spatial distribution of leg muscle oxygen saturation during ramp cycling exercise.
Takagi, Shun; Kime, Ryotaro; Murase, Norio; Watanabe, Tsubasa; Osada, Takuya; Niwayama, Masatsugu; Katsumura, Toshihito
2013-01-01
We compared muscle oxygen saturation (SmO2) responses in several leg muscles and within a single muscle during ramp cycling exercise between elderly men (n = 8; age, 65 ± 3 years; ELD) and young men (n = 10; age, 23 ± 3 years; YNG). SmO2 was monitored at the distal site of the vastus lateralis (VLd), proximal site of the vastus lateralis (VLp), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and tibialis anterior (TA) by near-infrared spatial resolved spectroscopy. During submaximal exercise, significantly lower SmO2 at a given absolute work rate was observed in VLd, RF, BF, GL, and TA but not in VLp, VM, and GM in ELD than in YNG. In contrast, at all measurement sites, SmO2 at peak exercise was not significantly different between groups. These results indicate that the effects of aging on SmO2 responses are heterogeneous between leg muscles and also within a single muscle. The lower SmO2 in older men may have been caused by reduced muscle blood flow or altered blood flow distribution.
Conventional plating methods were used to quantify heterotrophic bacteria from a drinking water distribution system. Three media, plate count agar (PCA), R2A agar and sheep blood agar (TSA-SB) were used to determine heterotrophic plate count (HPC) levels. Grab samples were collec...
NASA Astrophysics Data System (ADS)
Ma, Jun; Wang, Song; Wu, Zhenyu; Fan, Zhou; Zhang, Tianmen; Wu, Jianghua; Zhou, Xu; Jiang, Zhaoji; Chen, Jiansheng
2012-02-01
B514 is a remote M31 globular cluster (GC) which is located at a projected distance of Rp ~= 55 kpc. Deep observations with the Advanced Camera for Surveys on the Hubble Space Telescope are used to provide accurate integrated light and star counts of B514. By coupling the analysis of the distribution of the integrated light with star counts, we are able to reliably follow the profile of the cluster out to ~40''. Based on the combined profile, we study in detail its surface brightness distribution in the F606W and F814W filters and determine its structural parameters by fitting a single-mass isotropic King model. The results showed that the surface brightness distribution departs from the best-fit King model for r > 10''. B514 is quite flat in the inner region and has a larger half-light radius than the majority of normal GCs of the same luminosity. It is interesting that, in the MV versus log Rh plane, B514 lies nearly on the threshold for ordinary GCs as defined by Mackey & van den Bergh. In addition, B514 was observed as part of the Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey, using 13 intermediate-band filters covering a wavelength range of 3000-8500 Å. Based on aperture photometry, we obtain its spectral energy distributions (SEDs) as defined by the 13 BATC filters. We determine the cluster's age and mass by comparing its SEDs (from 2267 to 20000 Å, comprised of photometric data from the near-ultraviolet band of the Galaxy Evolution Explorer, 5 Sloan Digital Sky Survey bands, 13 BATC intermediate-band filters, and Two Micron All Sky Survey near-infrared JHK s filters) with theoretical stellar population synthesis models, resulting in an age of 11.5 ± 3.5 Gyr. This age confirms the previous suggestion that B514 is an old GC in M31. B514 has a mass of 0.96-1.08 × 106 M ⊙ and is a medium-mass GC in M31.
This report presents results of a study to determine the distribution of pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) between dust and carpet components in aged carpeting. Carpeting in eight homes in the Research Triangle Area, which...
Extended moment series and the parameters of the negative binomial distribution
Bowman, K.O.
1984-03-01
Recent studies indicate that, for finite sample sizes, moment estimators may be superior to maximum likelihood estimators in some regions of parameter space. In this paper a statistic based on the central moment of the sample is expanded in a Taylor series using 24 derivatives and many more terms than previous expansions. A summary algorithm is required to find meaningful approximants using the higher-order coefficients. A example is presented and a comparison between theoretical assessment and simulation results is made.
Dyer, Kathryn J; Perryman, Barry L; Holcombe, Dale W
2010-01-01
Decreases in Greater Sage Grouse (Centrocercus urophasianus) numbers throughout the western United States have been attributed to declining habitat quantity and quality. Improving our understanding of how interannual ecologic site variability affects nutritional status and fitness of different bird age classes will lead to improved land management and conservation strategies. Greater Sage Grouse were sampled from two Population Management Units located in northern Nevada, United States: Tuscarora (TU) and Lone Willow (LW) during 15 March-11 April 2004 and 14-20 March 2005. Twenty (16 yearlings, four adults) and 17 (7 yearlings, 10 adults) female Sage Grouse were captured and bled during 2004, and 12 (four yearlings, eight adults) and 14 (10 yearlings, four adults) were sampled during 2005 in TU and LW, respectively. Samples were evaluated to examine the effect of site, age, and year on specific hematologic and serum chemistry parameters. Several differences between age classes, sites, and years were detected for a number of fitness indicators; however, actual values fell within normal ranges of variation for Sage Grouse or other avian species. Differences were also detected for several parameters more closely related to reproductive fitness, including total plasma and serum proteins, and serum calcium and phosphorus. Yearlings had lower plasma protein (P<0.0001) and lower serum protein than did adults (P=0.0003). In 2004, TU yearlings had lower serum calcium levels than the adults, and in 2005, LW yearlings had lower levels than adults (P=0.008). Females on the TU site had lower serum phosphorus than the LW females (P<0.0001). Overall, adult females weighed more than yearlings (P=0.0004). Lower values found in yearlings, and on the TU management unit, indicate a lower production potential, particularly in unfavorable years. A lower intrinsic ability of yearlings to reproduce, combined with lower nutrition potentials and associated annual variations on certain types
Role of body fat distribution in the decline in insulin sensitivity and glucose tolerance with age.
Coon, P J; Rogus, E M; Drinkwater, D; Muller, D C; Goldberg, A P
1992-10-01
The relationships of body composition and physical fitness [maximal aerobic capacity (VO2max)] to the decline in insulin sensitivity with age were examined in healthy older (47-73 yr; n = 36) and young (19-36 yr; n = 13) men. In 18 older men with normal glucose tolerance (OGTT), glucose disposal rates (M) during hyperinsulinemic euglycemic clamps correlated negatively with the waist to hip ratio (WHR; r = -0.77; P < .001) and percent body fat (r = -0.46; P < 0.05) and positively with VO2max (r = 0.54; P < 0.05), but not with age. Similar relationships existed in the 36 older men with a spectrum of OGTT responses; however, only WHR was independently related to M (r2 = 0.32; P < 0.01). In the older men with normal OGTT, M (mean +/- SEM, 7.88 +/- 0.43 mg/kg fat-free mass.min) was not different from that in the young men (8.56 +/- 0.47; P = NS). Furthermore, in older and young men with normal OGTT matched for WHR, percent fat, or VO2max, glucose disposal was comparable at sequential 15-min intervals during the clamp and in its relationship to insulin concentrations at the tissue level (multicompartmental analysis). In contrast, despite higher steady state plasma insulin levels during the clamp, M was significantly lower in the older men with a higher WHR, greater percent fat, lower VO2max, or impaired OGTT. Thus, in healthy older men up to the age of 73 yr, insulin sensitivity and glucose tolerance are affected primarily by the regional body fat distribution, not age, obesity, or VO2max.
NASA Technical Reports Server (NTRS)
Alkasab, K. A.; Abdul-Aziz, A.
1991-01-01
The influence of thermophysical properties and flow rate on the steady-state temperature distribution in a phosphoric-acid fuel cell electrode plate was experimentally investigated. An experimental setup that simulates the operating conditions prevailing in a phosphoric-acid fuel cell stack was used. The fuel cell cooling system utilized three types of coolants to remove excess heat generated in the cell electrode and to maintain a reasonably uniform temperature distribution in the electrode plate. The coolants used were water, engine oil, and air. These coolants were circulated at Reynolds number ranging from 1165 to 6165 for water; 3070 to 6864 for air; and 15 to 79 for oil. Experimental results are presented.
Rixrath, E; Wendling-Mansuy, S; Flecher, X; Chabrand, P; Argenson, J N
2008-01-01
We have developed a mathematical model to calculate the contact stress distribution in total hip arthroplasty (THA) prosthesis between the articulating surfaces. The model uses the clearance between bearing surfaces as well as the inclination and thickness of the Ultra High Molecular Weight Poly-Ethylene (UHMWPE) cup to achieve this. We have used this mathematical model to contrast the maximal force during normal gait and during jogging. This is based on the assumption that the contact stress is proportional to the radial deformation of the cup. The results show that the magnitude of the maximal contact stress remains constant for inclination values in the range of [0-35 degrees ] and increase significantly with the cup clearance and liner thickness for inclination values in the range of [35-65 degrees ]. A major use for this model would be the calculation of spatial contact stress distribution during normal gait or jogging for different couples of bearing surfaces. PMID:18234204
Leavesley, G.H.; Markstrom, S.L.; Restrepo, P.J.; Viger, R.J.
2002-01-01
A modular approach to model design and construction provides a flexible framework in which to focus the multidisciplinary research and operational efforts needed to facilitate the development, selection, and application of the most robust distributed modelling methods. A variety of modular approaches have been developed, but with little consideration for compatibility among systems and concepts. Several systems are proprietary, limiting any user interaction. The US Geological Survey modular modelling system (MMS) is a modular modelling framework that uses an open source software approach to enable all members of the scientific community to address collaboratively the many complex issues associated with the design, development, and application of distributed hydrological and environmental models. Implementation of a common modular concept is not a trivial task. However, it brings the resources of a larger community to bear on the problems of distributed modelling, provides a framework in which to compare alternative modelling approaches objectively, and provides a means of sharing the latest modelling advances. The concepts and components of the MMS are described and an example application of the MMS, in a decision-support system context, is presented to demonstrate current system capabilities. Copyright ?? 2002 John Wiley and Sons, Ltd.
NASA Astrophysics Data System (ADS)
Hrachowitz, Markus; Savenije, Hubert; Soulsby, Chris; Tetzlaff, Doerthe
2013-04-01
The water storage and release dynamics at the catchment scale are still incompletely understood. This is in particular true when considering actual particle transport rather than only the hydraulic response. Environmental tracers are frequently instrumental in inferring transport process dynamics. Several recent research papers for example highlight the importance of difference time scales in transport dynamics. While on the short term, particle transport patterns can exhibit considerable variability, many catchments are characterized by near-chemostatic behaviour on the long term. In other words although the tracer response can show considerable fluctuations on the intra-annual scale, it remains surprisingly stable at the inter-annual scale. This suggests (1) that at the long term the composition of water can be largely independent of flow volumes and (2) that water as well as tracers/contaminants, once stored in a catchment can remain in the system for a very long time. Here we use long term (< 20 years) precipitation, flow and tracer (chloride) data of three contrasting upland catchments in the Scottish Highlands to inform integrated conceptual models investigating different mixing assumptions. Using the models as diagnostic tools in a functional comparison, water and tracer fluxes were then tracked with the objective of exploring the origin and pattern of near-chemostatic behaviour which manifests itself in long, power-law tails of water age distributions. The results highlight the potential importance of partial mixing processes in the generation of long tails in water age distributions. However, the degree to which partial mixing influences the generation of long tails is dependent on the hydrological functioning of a catchment. As second influential factor controlling the tailing behaviour of water age distributions was identified to be the interplay of flow path connectivity with the relative importance and timing of different flow paths. This understanding
ERIC Educational Resources Information Center
Himpens, E.; Van den Broeck, C.; Oostra, A.; Calders, P.; Vanhaesebrouck, P.
2008-01-01
The aim of this review is to determine the relationship between gestational age (GA) and prevalence, type, distribution, and severity of cerebral palsy (CP). Epidemiological studies with cohorts expressed by GA were assessed. A comprehensive meta-analysis and meta-regression was performed on four fetal age categories. Studies of children with CP…
The statistical analysis of the color—orbit parameters and color—inclination distributions of TNOs
NASA Astrophysics Data System (ADS)
Nabiyev, Shaig; Simonia, Irakli
2016-10-01
The research of the surface properties of the trans-Neptunian Objects (TNOs) is the key factor to obtain information about past and current status of our Solar System. Because of the far distance from the Sun the photometric investigations remain the most popular approaching way to study of physical conditions of TNOs. For this reason, we examine the correlation between 294 known B-R and 259 V-R color indexes and the orbital parameters of the trans-Neptunian Objects (TNOs) with by classification is giving in the literature: Cubewanos (Classical KBOs), Plutinos, Sentaurs, SDOs, Other TNOs, and Resonants, and subgroups by diameters greater than 80 km. Almost all inclinations of subgroups by classifications and diameters are strongly correlated with B-R and V-R indexes. Simultaneously, the remarkable and moderate correlations with high significance levels were found in 8 cases for B-R and other orbit parameters: semi-major axis, eccentricity, perihelion and diameters by diameter subgroups and 9 cases by classifications. Moreover, only 4 of 11 moderate correlation coefficients with high significance levels for V-R were calculated by classifications and 6 cases by diameters.
Parameter Estimation in Astronomy with Poisson-Distributed Data. 1; The (CHI)2(gamma) Statistic
NASA Technical Reports Server (NTRS)
Mighell, Kenneth J.
1999-01-01
Applying the standard weighted mean formula, [Sigma (sub i)n(sub i)ssigma(sub i, sup -2)], to determine the weighted mean of data, n(sub i), drawn from a Poisson distribution, will, on average, underestimate the true mean by approx. 1 for all true mean values larger than approx.3 when the common assumption is made that the error of the i th observation is sigma(sub i) = max square root of n(sub i), 1).This small, but statistically significant offset, explains the long-known observation that chi-square minimization techniques which use the modified Neyman'chi(sub 2) statistic, chi(sup 2, sub N) equivalent Sigma(sub i)((n(sub i) - y(sub i)(exp 2)) / max(n(sub i), 1), to compare Poisson - distributed data with model values, y(sub i), will typically predict a total number of counts that underestimates the true total by about 1 count per bin. Based on my finding that weighted mean of data drawn from a Poisson distribution can be determined using the formula [Sigma(sub i)[n(sub i) + min(n(sub i), 1)](n(sub i) + 1)(exp -1)] / [Sigma(sub i)(n(sub i) + 1)(exp -1))], I propose that a new chi(sub 2) statistic, chi(sup 2, sub gamma) equivalent, should always be used to analyze Poisson- distributed data in preference to the modified Neyman's chi(exp 2) statistic. I demonstrated the power and usefulness of,chi(sub gamma, sup 2) minimization by using two statistical fitting techniques and five chi(exp 2) statistics to analyze simulated X-ray power - low 15 - channel spectra with large and small counts per bin. I show that chi(sub gamma, sup 2) minimization with the Levenberg - Marquardt or Powell's method can produce excellent results (mean slope errors approx. less than 3%) with spectra having as few as 25 total counts.
[Health Care Insurance in France: its impact on income distribution between age and social groups].
Fourcade, N; Duval, J; Lardellier, R
2013-08-01
Our study, based on microsimulation models, evaluates the redistributive impact of health care insurance in France on income distribution between age and social groups. This work sheds light on the debate concerning the respective role of the public health care insurance (PHI) and the private supplemental health care insurance (SHI) in France. The analysis points out that the PHI enables the lowest-income households and the pensioners a better access to health care than they would have had under a complete private SHI. Due to the progressivity of taxes, low-income households contribute less to the PHI and get higher benefits because of a weaker health. Pensioners have low contributions to public health care finance but the highest health care expenditures.
Age rationing and the just distribution of health care: is there a duty to die?
Battin, Margaret Pabst
1987-01-01
The author analyzes the argument that a policy involving distributive justice in the allocation of scarce health care resources, based on the strategy of rational self interest maximation under a veil of ignorance (Rawls/Daniels), would result in an age rationing system of voluntary, socially encouraged, direct termination of the lives of the elderly rather than their medical abandonment. She maintains that such a policy would be a fair response only in a situation of substantial scarcity of resources that cannot be relieved without introducing greater injustices. Battin suggests that some of the current pressure on resources could be reduced by pruning waste and the expenses attributable to paternalistic imposition of treatment and to the practice of defensive medicine. She also advocates reconsideration of societal priorities assigned to various social goods.
Inskeep, William P.; Jay, Zackary J.; Tringe, Susannah G.; Herrgård, Markus J.; Rusch, Douglas B.
2013-01-01
The Yellowstone geothermal complex contains over 10,000 diverse geothermal features that host numerous phylogenetically deeply rooted and poorly understood archaea, bacteria, and viruses. Microbial communities in high-temperature environments are generally less diverse than soil, marine, sediment, or lake habitats and therefore offer a tremendous opportunity for studying the structure and function of different model microbial communities using environmental metagenomics. One of the broader goals of this study was to establish linkages among microbial distribution, metabolic potential, and environmental variables. Twenty geochemically distinct geothermal ecosystems representing a broad spectrum of Yellowstone hot-spring environments were used for metagenomic and geochemical analysis and included approximately equal numbers of: (1) phototrophic mats, (2) “filamentous streamer” communities, and (3) archaeal-dominated sediments. The metagenomes were analyzed using a suite of complementary and integrative bioinformatic tools, including phylogenetic and functional analysis of both individual sequence reads and assemblies of predominant phylotypes. This volume identifies major environmental determinants of a large number of thermophilic microbial lineages, many of which have not been fully described in the literature nor previously cultivated to enable functional and genomic analyses. Moreover, protein family abundance comparisons and in-depth analyses of specific genes and metabolic pathways relevant to these hot-spring environments reveal hallmark signatures of metabolic capabilities that parallel the distribution of phylotypes across specific types of geochemical environments. PMID:23653623
Inskeep, William P; Jay, Zackary J; Tringe, Susannah G; Herrgård, Markus J; Rusch, Douglas B
2013-01-01
The Yellowstone geothermal complex contains over 10,000 diverse geothermal features that host numerous phylogenetically deeply rooted and poorly understood archaea, bacteria, and viruses. Microbial communities in high-temperature environments are generally less diverse than soil, marine, sediment, or lake habitats and therefore offer a tremendous opportunity for studying the structure and function of different model microbial communities using environmental metagenomics. One of the broader goals of this study was to establish linkages among microbial distribution, metabolic potential, and environmental variables. Twenty geochemically distinct geothermal ecosystems representing a broad spectrum of Yellowstone hot-spring environments were used for metagenomic and geochemical analysis and included approximately equal numbers of: (1) phototrophic mats, (2) "filamentous streamer" communities, and (3) archaeal-dominated sediments. The metagenomes were analyzed using a suite of complementary and integrative bioinformatic tools, including phylogenetic and functional analysis of both individual sequence reads and assemblies of predominant phylotypes. This volume identifies major environmental determinants of a large number of thermophilic microbial lineages, many of which have not been fully described in the literature nor previously cultivated to enable functional and genomic analyses. Moreover, protein family abundance comparisons and in-depth analyses of specific genes and metabolic pathways relevant to these hot-spring environments reveal hallmark signatures of metabolic capabilities that parallel the distribution of phylotypes across specific types of geochemical environments.
Inskeep, William P; Jay, Zackary J; Tringe, Susannah G; Herrgård, Markus J; Rusch, Douglas B
2013-01-01
The Yellowstone geothermal complex contains over 10,000 diverse geothermal features that host numerous phylogenetically deeply rooted and poorly understood archaea, bacteria, and viruses. Microbial communities in high-temperature environments are generally less diverse than soil, marine, sediment, or lake habitats and therefore offer a tremendous opportunity for studying the structure and function of different model microbial communities using environmental metagenomics. One of the broader goals of this study was to establish linkages among microbial distribution, metabolic potential, and environmental variables. Twenty geochemically distinct geothermal ecosystems representing a broad spectrum of Yellowstone hot-spring environments were used for metagenomic and geochemical analysis and included approximately equal numbers of: (1) phototrophic mats, (2) "filamentous streamer" communities, and (3) archaeal-dominated sediments. The metagenomes were analyzed using a suite of complementary and integrative bioinformatic tools, including phylogenetic and functional analysis of both individual sequence reads and assemblies of predominant phylotypes. This volume identifies major environmental determinants of a large number of thermophilic microbial lineages, many of which have not been fully described in the literature nor previously cultivated to enable functional and genomic analyses. Moreover, protein family abundance comparisons and in-depth analyses of specific genes and metabolic pathways relevant to these hot-spring environments reveal hallmark signatures of metabolic capabilities that parallel the distribution of phylotypes across specific types of geochemical environments. PMID:23653623
Boligon, Arione Augusti; Baldi, Fernando; de Albuquerque, Lucia Galvão
2011-01-01
Records from 106,212 Nellore animals, born between 1998 and 2006, were used to estimate (co)variance components and genetic parameters for birth weight (BW), average weight gains from birth to weaning (GBW), average weight gains from weaning to after yearling (GWAY), weaning hip height (WHH), postweaning hip height (PHH) and scrotal circumferences at 9 (SC9), 12 (SC12) and 15 (SC15) months of age. (Co)variance components were estimated by an animal model using multi-trait analysis. Heritability estimates for BW, GBW, GWAY, WHH, PHH, SC9, SC12 and SC15 were 0.31 ± 0.01; 0.25 ± 0.02; 0.30 ± 0.04; 0.51 ± 0.04; 0.54 ± 0.04; 0.39 ± 0.01; 0.41 ± 0.01 and 0.44 ± 0.02, respectively. Genetic correlations between growth traits ranged from 0.09 ± 0.01 to 0.88 ± 0.01, thereby implying that, at any age, selection to increase average weight gains will also increase stature. Genetic correlations between BW and average weight gains with scrotal circumferences were all positive and moderate (0.15 ± 0.03 to 0.38 ± 0.01). On the other hand, positive and low genetic associations were estimated between hip height and scrotal circumference at different ages (0.09 ± 0.01 to 0.17 ± 0.02). The results of this study pointed out that selection to larger scrotal circumferences in males will promote changes in average weight gains. In order to obtain Nellore cattle with the stature and size suitable for the production system, both weight gain and hip height should be included in a selection index. PMID:21734821
Cost-effective age structure and geographical distribution of boreal forest reserves.
Lundström, Johanna; Ohman, Karin; Perhans, Karin; Rönnqvist, Mikael; Gustafsson, Lena; Bugman, Harald
2011-02-01
1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied.2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area.3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages ≥ 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0-14 years than in forests 15-69 years.4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area.5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class.6.Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and cost
Gogolak, C.V.
1986-01-01
The concentration of a contaminant measured in a particular medium might be distributed as a positive random variable when it is present, but it may not always be present. Suppose that in the underlying population, the value zero occurs with probability delta, and that the conditional distribution given the value is nonzero, is that of a positive random variable. If there is a level below which the concentration cannot be distinguished from zero by the analytical apparatus, a sample from such a population will be censored on the left. The presence of both zeros and positive values in the censored portion of such samples complicates the problem of estimating the parameters of the underlying positive random variable and the probability of a zero observation. Using the method of maximum likelihood, it is shown that the solution to this estimation problem reduces largely to that of estimating the parameters of the distribution truncated at the point of censorship. The maximum likelihood estimate of the proportion of zero values follows directly. The derivation of the maximum likelihood estimates for a lognormal population with zeros is given in detail, and the asymptotic properties of the estimates are examined. Simulation studies were performed to study the small sample behavior of the estimates, and to compare them to previously suggested methods for handling such data. The estimation method was used to fit several different distributions to a set of severely censored /sup 85/Kr monitoring data from six locations at the Savannah River Plant chemical separations facilities. The results for lognormal, exponential, gamma, Weibull, and inverse Gaussian distributions with zeros are discussed and compared.
NASA Astrophysics Data System (ADS)
Drumea, Andrei; Ilie, Ioana; Vasile, Alexandru; Svasta, Paul; Tapu, Adina
2009-01-01
Rigorous monitoring of technological parameters optimizes the activities and reduces energy losses in distribution points of heat and water from utility companies. Extra efficiency can be achieved by remote monitoring via Internet or GSM communications and using networks of wireless sensors for collecting data. Presented paper focuses on hardware and software design aspects of wireless sensors for measuring parameters required by water and heat distribution, with focus on flow and temperature measurement. The sensors consist of two modules - one control and communication unit and sensing unit. Sensing unit is specific to measured parameter (flow, temperature, humidity etc.) but control and communication unit is the same for all sensors. Software for sensing unit was developed and tested on a universal electronic module for industrial control. Sensors group together in a plug-and-play wireless mesh network and one of them is connected to an Internet/GSM communication module for remote access. Wireless sensors are battery based devices so energy management issues (hardware and software) play a big role in sensor design. Current consumption of different configurations and in different operation states is analyzed.
NASA Astrophysics Data System (ADS)
Kim, Kyung-Chan; Lee, Dae-Young; Shprits, Yuri
2015-02-01
Accurate knowledge of the global distribution of plasmaspheric hiss is essential for the radiation belt modeling because it provides a direct link to understanding the radiation belt loss in the slot region. In this paper, we study the dependence of hiss activity on solar wind parameters and geomagnetic activity indices using Time History of Events and Macroscale Interactions during Substorms hiss measurements made from 1 July 2008 to 30 June 2012 based on a correlation analysis. We find that hiss amplitudes are well correlated with the preceding solar wind speed VSW, interplanetary magnetic field (IMF) BZ, and interplanetary electric field (IEF) EY with delay times of 5-6 h for VSW and 3-4 h for IMF BZ and IEF EY, while the best correlation with the geomagnetic indices, AE, Kp, and SYM-H, occurs at a delay time of 2-3 h for AE and SYM-H and 3-4 h for Kp. Of the solar wind parameters, the dawn-to-dusk component of IEF EY yields the best correlation with the variation of hiss wave. More interestingly, the global distribution of hiss waves shows a significant dependence on the VSW and IMF BZ: the most intense hiss region tends to occur at prenoon sector for a more southward IMF BZ, while the tendency is opposite with increasing VSW. This implies different origins of hiss activity. Also, we employ an artificial neural network technique to develop models of the global distribution of hiss amplitudes based on the solar wind parameters and geomagnetic indices. The solely solar wind parameter-based model generally results in a higher correlation between the measured and modeled hiss amplitudes than any other models based on the geomagnetic indices. Finally, we use the solar wind parameter-based model to investigate hiss activity during storm events by distinguishing between coronal mass ejection-driven storms and corotating interaction region-driven storms. The result shows that in spite of the differences in the behavior of solar wind parameters between the two storm
NASA Astrophysics Data System (ADS)
Sun, Chunqing; You, Haitao; Liu, Jiaqi; Li, Xin; Gao, Jinliang; Chen, Shuangshuang
2014-04-01
Large explosive volcanic eruptions generate extensive regional tephra deposits that provide favorable conditions for identifying the source of volcanoes, comparing the sedimentary strata of a region and determining their ages. The tephra layer, referred to as BTm, generated by the Millennium eruption of Changbaishan volcano, is widely distributed in Northeast China, Japan, D.P.R. Korea, and the nearby coastal area of Russia. It forms part of the widespread northeast Asian strata and is significant for establishing an isochronal stratigraphic framework. However, research on the temporal characterization and stratigraphic correlation of associated strata using this tephra layer is mainly concentrated in and near Japan. In northeastern China, this tephra layer is seldom seen and its application in stratigraphic correlations is even rarer. More importantly, the determination of accurate ages for both distal and proximal tephras has been debated, leading to controversy in discussions of its environmental impacts. Stratigraphic records from both distal and proximal Changbaishan ash show that this eruption generally occurred between 1,012 and 1,004 cal yr BP. Geochemical comparison between Changbaishan ash and the Quaternary widespread ash around Japan illustrates that Changbaishan ash is a continuous composition from rhyolitic to trachytic and its ratio of FeOT to CaO is usually greater than 4, which can be used as a distinguishing identifier among worldwide contemporary eruptions.
NASA Astrophysics Data System (ADS)
Sun, Chunqing; You, Haitao; Liu, Jiaqi; Li, Xin; Gao, Jinliang; Chen, Shuangshuang
2014-06-01
Large explosive volcanic eruptions generate extensive regional tephra deposits that provide favorable conditions for identifying the source of volcanoes, comparing the sedimentary strata of a region and determining their ages. The tephra layer, referred to as B-Tm, generated by the Millennium eruption of Changbaishan volcano, is widely distributed in Northeast China, Japan, D.P.R. Korea, and the nearby coastal area of Russia. It forms part of the widespread northeast Asian strata and is significant for establishing an isochronal stratigraphic framework. However, research on the temporal characterization and stratigraphic correlation of associated strata using this tephra layer is mainly concentrated in and near Japan. In northeastern China, this tephra layer is seldom seen and its application in stratigraphic correlations is even rarer. More importantly, the determination of accurate ages for both distal and proximal tephras has been debated, leading to controversy in discussions of its environmental impacts. Stratigraphic records from both distal and proximal Changbaishan ash show that this eruption generally occurred between 1,012 and 1,004 cal yr BP. Geochemical comparison between Changbaishan ash and the Quaternary widespread ash around Japan illustrates that Changbaishan ash is a continuous composition from rhyolitic to trachytic and its ratio of FeOT to CaO is usually greater than 4, which can be used as a distinguishing identifier among worldwide contemporary eruptions.
Sex and age distribution in transport-related injuries in Tehran.
Roudsari, Bahman Sayyar; Sharzei, Kaveh; Zargar, Moosa
2004-05-01
Intercountry or regional differences in patterns of injury by the road user type have significant implication for prevention policies. In order to have an estimate from the existing conditions of transport-related injuries (TRIs) and especially to evaluate sex and age distribution of traffic accident victims, we analyzed information of 8426 hospitalized trauma patients during 13 months of data gathering process. Forty-five percent of the injuries were related to car accidents and men/women ratio in these patients was 4.2/1. The highest men/women ratio was (16/1) for motorcyclists, while the lowest ratio (1/1), was for rear seat car passengers. Mean (+/-S.D.) age of the patients was 31 (+/-18), and men were nearly 2 years younger than women (33 versus 31). Sixty-seven percent of the females' and 44% of the males' injuries were related to pedestrian crashes. Motorcycle-related injuries in men and car passenger related injuries in women were the second most common type of crash (42 and 22%, respectively). The use of protective devices in our population was worrisome. In only 6% of the male motorcyclists helmet use was reported, and 3% of the male car occupants had used seatbelts at the time of the accident. The condition in the female population was much worse and no use of the protective devices was reported in this group of the patients. Crude mortality rate in men was nearly two times that of women (6.2% versus 3.8%). After adjustment for age, injury severity score (ISS) and category of the road users, men and women had similar mortality rate. PMID:15003584
NASA Astrophysics Data System (ADS)
Husson, L.; Conrad, C. P.
2009-12-01
The ongoing aggregation of Africa, Arabia, India and Australia onto Eurasia is forming a supercontinent that we refer to as Hapagea. Although not as large as the older Pangea and Rodinia, Hapageais nevertheless large enough to profoundly modify Cenozoic plate kinematics as it gradually becomes a hub apart from which American continents spread. The continuation of Atlantic spreading is carried out at the expense of the Pacific Ocean, forcing the Farallon / Nazca plates down into eastern Pacific subduction zones, despite the fact that this seafloor is theoretically too young and too buoyant to subduct efficiently. This process occurred later for South America, where the subduction of the Tethys buffered the impact of the Atlantic expansion, and earlier for North America where this configuration was never met. The implications of the current plate tectonics are multiple and include (i) increased compression on the western coasts of the Americas, leading to Cordillera formation in North America (Sevier and Laramide) and later in South America (Andean), (ii) the transition from a rectangular distribution of seafloor ages to a triangular distribution as westward progress of the Americas engulfs young Farallon/Nazca seafloor, and (iii) a decrease in the convective efficiency of mantle flow that results in decreased rates of lithospheric productionat ridges, a situation that is cyclically met during the Wilson cycle and diminishes both mantle heat flow and sea level. These results imply that mantle drag causes the Atlantic spread and dominates the force balance of the Earth’s lithospheric shell.
Age distributions and dynamically changing hydrologic systems: Exploring topography-driven flow
NASA Astrophysics Data System (ADS)
Gomez, J. D.; Wilson, J. L.
2013-03-01
Natural systems are driven by dynamic forcings that change in time as well as space, behavior that is inherited by the system flow field and results in time-varying age distributions (ADs). This work presents a review of the mathematical tools and solution approaches used to model ADs in dynamic time-varying flow systems. A simple conceptual, numerical model is then used to explore the role of flow dynamics in ADs for topography-driven flow systems. This model is an analog for regional groundwater systems and hyporheic zones. This model demonstrates that relatively small fluctuations in the forcing, even though importantly affecting the flow in the system, can have minimal effects in ADs. However, as the intensity of fluctuation increases, still within the bounds observed in natural systems, ADs in shallow parts of the system become highly sensitive to dynamic flow conditions, leading to considerable changes in the moments and modality of the distributions with time. In particular, transient flow can lead to emergence of new modes in the AD, which would not be present under steady flow conditions. The discrepancy observed between ADs under steady and transient flow conditions is explained by enhancement of mixing due to temporal variations in the flow field. ADs in deeper parts of the system are characterized by multimodality and tend to be more stable over time even for large forcing fluctuations.
Anninos, P; Zenone, S; Elul, R
1983-08-01
The statistical laws governing the output of a population of unitary generators are not explicit with regard to the effect of population size and properties of the individual generators on the summed activity. Experimental work was therefore undertaken with artificial nerve nets, the activity of which simulates with a high degree of realism individual nerve cells and the electroencephalogram. It was found that the summed activity is not affected by the statistical properties of single generators even in nets of only 200-1000 elements. On the other hand, the output of the net is highly sensitive to the level of connectivity between individual generators. When connectivity is low, the summed output is distributed in normal (Gaussian) fashion. The output of the net becomes less and less Gaussian with increase in coupling between the generators.
Distribution of crack density parameter in Central Betic Cordillera (Southern Spain)
NASA Astrophysics Data System (ADS)
Serrano, Inmaculada; Torcal, Federico; Morales, José
2014-01-01
In this study we have used high-resolution P- and S-wave velocity results to estimate crack density (ɛ, epsilon) and saturation ratio (ξ, xi) at a depth of 2 km in an intramountain basin and surrounding regions. Detailed observations of gravity, seismic profile and geological data reveal high ɛ consistent with large sedimentary thickness and minimum ɛ coinciding with elevations arising from the basement of the basin. From the distribution of seismic measurements of ξ it is possible to identify the presence of aquifers in detrital sediments, sandstone and dolostone. However, ξ does not show significant changes for the aquifers in geological formations made up also of schists and marbles. A low ξ anomaly in the western part could be associated with Triassic evaporite and clay rocks, and high values of ξ in the southwestern part near thermal springs may be imaging the intricate system of fractures which connect at depth with aquifer rocks.
NASA Technical Reports Server (NTRS)
Santiago-Perez, Julio
1988-01-01
The frequency and intensity of thunderstorms around the Kennedy Space Center (KSC) has affected scheduled launch, landing, and other ground operations for many years. In order to protect against and provide safe working facilities, KSC has performed and hosted several studies on lightning phenomena. For the reasons mentioned above, KSC has established the Atmospheric Science Field Laboratory (ASFL). At these facilities KSC launches wire-towing rockets into thunderstorms to trigger natural lightning to the launch site. A program named Rocket Triggered Lightning Program (RTLP) is being conducted at the ASFL. This report calls for two of the experiments conducted in the summer 1988 Rocket Triggered Lightning Program. One experiment suspended an electric field mill over the launching areas from a balloon about 500 meters high to measure the space charges over the launching area. The other was to connect a waveform recorder to a nearby distribution power line to record currents and voltages wave forms induced by natural and triggered lightning.
LARGE SCALE DISTRIBUTED PARAMETER MODEL OF MAIN MAGNET SYSTEM AND FREQUENCY DECOMPOSITION ANALYSIS
ZHANG,W.; MARNERIS, I.; SANDBERG, J.
2007-06-25
Large accelerator main magnet system consists of hundreds, even thousands, of dipole magnets. They are linked together under selected configurations to provide highly uniform dipole fields when powered. Distributed capacitance, insulation resistance, coil resistance, magnet inductance, and coupling inductance of upper and lower pancakes make each magnet a complex network. When all dipole magnets are chained together in a circle, they become a coupled pair of very high order complex ladder networks. In this study, a network of more than thousand inductive, capacitive or resistive elements are used to model an actual system. The circuit is a large-scale network. Its equivalent polynomial form has several hundred degrees. Analysis of this high order circuit and simulation of the response of any or all components is often computationally infeasible. We present methods to use frequency decomposition approach to effectively simulate and analyze magnet configuration and power supply topologies.
Dale, Daniel A.; Helou, George; Magdis, Georgios E.; Armus, Lee; Díaz-Santos, Tanio; Shi, Yong
2014-03-20
A two-parameter semi-empirical model is presented for the spectral energy distributions of galaxies with contributions to their infrared-submillimeter-radio emission from both star formation and accretion disk-powered activity. This model builds upon a previous one-parameter family of models for star-forming galaxies, and includes an update to the mid-infrared emission using an average template obtained from Spitzer Space Telescope observations of normal galaxies. Star-forming/active galactic nucleus (AGN) diagnostics based on polycyclic aromatic hydrocarbon equivalent widths and broadband infrared colors are presented, and example mid-infrared AGN fractional contributions are estimated from model fits to the Great Observatories All-Sky LIRG Survey sample of nearby U/LIRGS and the Five mJy Unbiased Spitzer Extragalactic Survey sample of 24 μm selected sources at redshifts 0 ≲ z ≲ 4.
Ground water age and nitrate distribution within a glacial aquifer beneath a thick unsaturated zone
Johnston, C.T.; Cook, P.G.; Frape, S.K.; Plummer, L.N.; Busenberg, E.; Blackport, R.J.
1998-01-01
The impact on ground water quality from increasing fertilizer application rates over the past 40 years is evaluated within a glacial aquifer system beneath a thick unsaturated zone. Ground water ages within the aquifer could not be accurately determined from the measured distribution of 3H and as a result, chlorofluorocarbon (CFC) and 3H/3He dating techniques were applied. Beneath a 25 m thick unsaturated zone, ground water ages based on CFC-11 concentrations were greater than 3H/3He ground water ages by 6 to 10 years, due to the time lag associated with the diffusion of CFCs through the unsaturated zone. Using the corrected CFC-11 and 3H/3He ground water ages and the estimated travel time of 3H within the unsaturated zone, the approximate position of ground water recharged since the mid-1960s was determined. Nitrate concentrations within post mid-1960s recharge were generally elevated and near or above the drinking water limit of 10 mg-N/L. In comparison, pre mid-1960s recharge had nitrate concentrations <2.5 mg-N/L. The elevated NO3- concentrations in post mid-1960s recharge are attributed mainly to increasing fertilizer application rates between 1970 and the mid- to late 1980s. Anaerobic conditions suitable for denitrification are present within pre mid-1960s recharge indicating that removal of DO is a slow process taking tens of years. Over the next 10 to 20 years, nitrate concentrations at municipal well fields that are currently capturing aerobic ground water recharged near the mid-1960s are expected to increase because of the higher fertilizer application rates beginning in the 1970s and 1980s.The impact on ground water quality from increasing fertilizer application rates over the past 40 years is evaluated within a glacial aquifer system beneath a thick unsaturated zone. Beneath a 25 m thick unsaturated zone, ground water ages based on CFC-11 concentrations were greater than 3H/3He ground water ages by 6 to 10 years, due to the time lag associated with the
NASA Astrophysics Data System (ADS)
Djorgovski, S.; Meylan, G.
1993-05-01
The forthcoming ASPCS volume, ``Structure and Dynamics of Globular Clusters'' (expected publication date: early summer of 1993) will contain a set of appendices with data resources on Galactic globular clusters; the authors of these papers include I.R. King, S. Peterson, C.T. Pryor, S.C. Trager, and ourselves. From these papers we have compiled a data base of various observed and derived parameters for globular clusters (143 of them at last count). Our main purpose is to use these data for correlative studies of globular cluster properties. Others may find it useful for similar purposes, for planning and support of observations, for testing of theoretical models, etc. We will describe the data base, and present some simple analysis of the cluster properties and correlations among them. The data will be made available to the community in a computer form, as ASCII files. Interested users should send an email message to the Internet address: george @ deimos.caltech.edu, and may also find the above mentioned ASPCS volume useful in their work. We thank our colleagues who contributed data for this compilation for their efforts. S.D. acknowledges a partial support from the NASA contract NAS5-31348, and the NSF PYI award AST-9157412.
NASA Astrophysics Data System (ADS)
Bulatova, Dr.
2012-04-01
Modern research in the domains of Earth sciences is developing from the descriptions of each individual natural phenomena to the systematic complex research in interdisciplinary areas. For studies of its kind in the form numerical analysis of three-dimensional (3D) systems, the author proposes space-time Technology (STT), based on a Ptolemaic geocentric system, consist of two modules, each with its own coordinate system: (1) - 3D model of a Earth, the coordinates of which provides databases of the Earth's events (here seismic), and (2) - a compact model of the relative motion of celestial bodies in space - time on Earth known as the "Method of a moving source" (MDS), which was developed in MDS (Bulatova, 1998-2000) for the 3D space. Module (2) was developed as a continuation of the geocentric Ptolemaic system of the world, built on the astronomical parameters heavenly bodies. Based on the aggregation data of Space and Earth Sciences, systematization, and cooperative analysis, this is an attempt to establish a cause-effect relationship between the position of celestial bodies (Moon, Sun) and Earth's seismic events.
Distributed and Lumped Parameter Models for the Characterization of High Throughput Bioreactors
Conoscenti, Gioacchino; Cutrì, Elena; Tuan, Rocky S.; Raimondi, Manuela T.; Gottardi, Riccardo
2016-01-01
Next generation bioreactors are being developed to generate multiple human cell-based tissue analogs within the same fluidic system, to better recapitulate the complexity and interconnection of human physiology [1, 2]. The effective development of these devices requires a solid understanding of their interconnected fluidics, to predict the transport of nutrients and waste through the constructs and improve the design accordingly. In this work, we focus on a specific model of bioreactor, with multiple input/outputs, aimed at generating osteochondral constructs, i.e., a biphasic construct in which one side is cartilaginous in nature, while the other is osseous. We next develop a general computational approach to model the microfluidics of a multi-chamber, interconnected system that may be applied to human-on-chip devices. This objective requires overcoming several challenges at the level of computational modeling. The main one consists of addressing the multi-physics nature of the problem that combines free flow in channels with hindered flow in porous media. Fluid dynamics is also coupled with advection-diffusion-reaction equations that model the transport of biomolecules throughout the system and their interaction with living tissues and C constructs. Ultimately, we aim at providing a predictive approach useful for the general organ-on-chip community. To this end, we have developed a lumped parameter approach that allows us to analyze the behavior of multi-unit bioreactor systems with modest computational effort, provided that the behavior of a single unit can be fully characterized. PMID:27669413
Toward the Distribution of Orbital Parameters of Nearby Major Galaxy Mergers
NASA Astrophysics Data System (ADS)
Mortazavi Karvani, Seyed Alireza
2016-01-01
In this thesis project our goal is to measure the initial conditions of a sample of ~20 local disk-disk major galaxy mergers. Measuring the orbital parameters is possible by findingthe most similar galaxy merger simulation to the morphology and kinematics of the data.We have developed an automated modeling method based on the Identikit software package,which also estimates the uncertainty of the measured initial conditions. We tested our modeling method using an independent set of GADGET simulations, and we acquired reliable results onprograde merger systems. We observed the Hα kinematics of our sample using SparsePak IFU on the WIYN telescope at KPNO, and DIS on the 3.5m telescope at APO. For the few merger systems in our sample with archival HI data available, we compare the use of HI vs Hα as the kinematic tracer. This work lays the ground-work for the analysis of larger statistical samples of mergers from on-going IFU galaxy survey such as MaNGA.
Joint min-max distribution and Edwards-Anderson's order parameter of the circular 1/f-noise model
NASA Astrophysics Data System (ADS)
Cao, Xiangyu; Le Doussal, Pierre
2016-05-01
We calculate the joint min-max distribution and the Edwards-Anderson's order parameter for the circular model of 1/f-noise. Both quantities, as well as generalisations, are obtained exactly by combining the freezing-duality conjecture and Jack-polynomial techniques. Numerical checks come with significantly improved control of finite-size effects in the glassy phase, and the results convincingly validate the freezing-duality conjecture. Application to diffusive dynamics is discussed. We also provide a formula for the pre-factor ratio of the joint/marginal Carpentier-Le Doussal tail for minimum/maximum which applies to any logarithmic random energy model.
Chip Weseloh, D V; Ewins, P J; Struger, J; Mineau, P; Norstrom, R J
1994-02-01
As part of the Great Lakes International Surveillance Plan, 1978-83, egg contaminant levels and reproductive output were determined for Herring Gull colonies on Lake Superior in 1983. Since 1974, the Herring Gull has been widely used in the Great Lakes as a spatial and temporal monitor of organochlorine (OC) contaminant levels and associated biological effects. Most eggs contained a wide range of OCs, the main compounds being DDE, polychlorinated biphenyls (PCBs), dieldrin, heptachlor epoxide, oxychlordane, hexachlorobenzene and mirex. Levels of an additional ten OCs and five polychlorinated dibenzo-p-dioxin (PCDD) congeners were also determined for some sites. Overall, levels varied significantly among colonies, but there was no obvious relationship to spatial distribution of contaminants in sediments or fish species. OC levels in eggs had declined by up to 84% since 1974. Eggshells were only 8% thinner than before the introduction of DDT, and shell thinning was not a cause of breeding failure. Average reproductive output varied from 0.15 to 1.57 young per apparently occupied nest in 1983: at 56% of colonies the value was below that thought necessary to maintain stable populations. The main causes of failure were egg disappearence and cannibalism of chicks. Despite this, the population appeared to have been increasing at about 4% per annum. Reduced availability of forage fish during the early 1980s was the most likely reason for the poor reproductive output in 1983. PMID:24221346
NASA Astrophysics Data System (ADS)
Sheffer, Daniel B.; Schaer, Alex R.; Baumann, Juerg U.
1989-04-01
Inclusion of mass distribution information in biomechanical analysis of motion is a requirement for the accurate calculation of external moments and forces acting on the segmental joints during locomotion. Regression equations produced from a variety of photogrammetric, anthropometric and cadaeveric studies have been developed and espoused in literature. Because of limitations in the accuracy of predicted inertial properties based on the application of regression equation developed on one population and then applied on a different study population, the employment of a measurement technique that accurately defines the shape of each individual subject measured is desirable. This individual data acquisition method is especially needed when analyzing the gait of subjects with large differences in their extremity geo-metry from those considered "normal", or who may possess gross asymmetries in shape in their own contralateral limbs. This study presents the photogrammetric acquisition and data analysis methodology used to assess the inertial tensors of two groups of subjects, one with spastic diplegic cerebral palsy and the other considered normal.
NASA Astrophysics Data System (ADS)
Facca, C.; Sfriso, A.
2007-10-01
The benthic diatom abundance and taxonomic composition were investigated in the Venice lagoon to integrate the knowledge on the trophic food web of shallow coastal areas. Samples of surface sediment layer (ca. 1 cm) were collected and stored until inverted light microscope determination. One-year comparison was carried out in six sites with a monthly frequency. In summer 2003, sediment cores were also collected at 165 stations distributed throughout the whole lagoon. Abundance varied between 0.26 and 5.65 × 10 6 cells ml -1, whereas the Shannon diversity index ranged between 0.93 and 4.36 H' depending on seasonal and spatial variability. The seasonal variations were not correlated with water temperature, although it varied between 6 and 29 °C, but with nutrient concentrations, sediment re-suspension and grain size. The spatial fluctuations mostly were influenced by water turbidity. Amphora, Cocconeis, Navicula, Nitzschia and Thalassiosira were the most common genera. Thalassiosira sp. constituted an interesting case as it was quite abundant near the mainland and was correlated with nutrient concentrations. The community structure was investigated by applying univariate and multivariate statistical analysis such as cumulative dominance curves, cluster analysis and canonical correspondence analysis.
NASA Astrophysics Data System (ADS)
Walker, Matthew G.; Mateo, Mario; Olszewski, Edward W.; Sen, Bodhisattva; Woodroofe, Michael
2009-02-01
We develop an algorithm for estimating parameters of a distribution sampled with contamination. We employ a statistical technique known as "expectation maximization" (EM). Given models for both member and contaminant populations, the EM algorithm iteratively evaluates the membership probability of each discrete data point, then uses those probabilities to update parameter estimates for member and contaminant distributions. The EM approach has wide applicability to the analysis of astronomical data. Here we tailor an EM algorithm to operate on spectroscopic samples obtained with the Michigan-MIKE Fiber System (MMFS) as part of our Magellan survey of stellar radial velocities in nearby dwarf spheroidal (dSph) galaxies. These samples, to be presented in a companion paper, contain discrete measurements of line-of-sight velocity, projected position, and pseudo-equivalent width of the Mg-triplet feature, for ~1000-2500 stars per dSph, including some fraction of contamination by foreground Milky Way stars. The EM algorithm uses all of the available data to quantify dSph and contaminant distributions. For distributions (e.g., velocity and Mg-index of dSph stars) assumed to be Gaussian, the EM algorithm returns maximum-likelihood estimates of the mean and variance, as well as the probability that each star is a dSph member. These probabilities can serve as weights in subsequent analyses. Applied to our MMFS data, the EM algorithm identifies more than 5000 stars as probable dSph members. We test the performance of the EM algorithm on simulated data sets that represent a range of sample size, level of contamination, and amount of overlap between dSph and contaminant velocity distributions. The simulations establish that for samples ranging from large (N ~ 3000, characteristic of the MMFS samples) to small (N ~ 30), resembling new samples for extremely faint dSphs), the EM algorithm distinguishes members from contaminants and returns accurate parameter estimates much more
Dopita, M A; Fischera, J; Sutherland, R S; Kewley, L J; Tuffs, R J; Popescu, C C; van Breugel, W; Groves, B A; Leitherer, C
2006-03-01
We examine from a theoretical viewpoint how the physical parameters of H II regions are controlled both in normal galaxies and in starburst environments. These parameters are the H II region luminosity function, the time-dependent size, the covering fraction of molecular clouds, the pressure in the ionized gas and the ionization parameter. The factors which control them are the initial mass function of the exciting stars, the cluster mass function, the metallicity and the mean pressure in the surrounding interstellar medium. We investigate the sensitivity of the H{alpha} luminosity to the IMF, and find that this can translate to about 30% variation in derived star formation rates. The molecular cloud dissipation timescale is estimated from a case study of M17 to be {approx} 1 Myr. Based upon H II luminosity function fitting for nearby galaxies, we propose that the cluster mass function has a log-normal form peaking at {approx} 185M{sub {circle_dot}}. This suggests that the cluster mass function is the continuation of the stellar IMF to higher mass. The pressure in the H II regions is controlled by the mechanical luminosity flux from the central cluster. Since this is closely related to the ionizing photon flux, we show that the ionization parameter is not a free variable, and that the diffuse ionized medium may be composed of many large, faint and old H II regions. Finally, we derive theoretical probability distributions for the ionization parameter as a function of metallicity and compare these to those derived for SDSS galaxies.
Muscle-specific 4E-BP1 signaling activation improves metabolic parameters during aging and obesity
Tsai, Shihyin; Sitzmann, Joanna M.; Dastidar, Somasish G.; Rodriguez, Ariana A.; Vu, Stephanie L.; McDonald, Circe E.; Academia, Emmeline C.; O’Leary, Monique N.; Ashe, Travis D.; La Spada, Albert R.; Kennedy, Brian K.
2015-01-01
Eukaryotic translation initiation factor 4E–binding protein 1 (4E-BP1) is a key downstream effector of mTOR complex 1 (mTORC1) that represses cap-dependent mRNA translation initiation by sequestering the translation initiation factor eIF4E. Reduced mTORC1 signaling is associated with life span extension and improved metabolic homeostasis, yet the downstream targets that mediate these benefits are unclear. Here, we demonstrated that enhanced 4E-BP1 activity in mouse skeletal muscle protects against age- and diet-induced insulin resistance and metabolic rate decline. Transgenic animals displayed increased energy expenditure; altered adipose tissue distribution, including reduced white adipose accumulation and preserved brown adipose mass; and were protected from hepatic steatosis. Skeletal muscle–specific 4E-BP1 mediated metabolic protection directly through increased translation of peroxisome proliferator–activated receptor γ coactivator-1α (PGC-1α) and enhanced respiratory function. Non–cell autonomous protection was through preservation of brown adipose tissue metabolism, which was increased in 4E-BP1 transgenic animals during normal aging and in a response to diet-induced type 2 diabetes. Adipose phenotypes may derive from enhanced skeletal muscle expression and secretion of the known myokine FGF21. Unlike skeletal muscle, enhanced adipose-specific 4E-BP1 activity was not protective but instead was deleterious in response to the same challenges. These findings indicate that regulation of 4E-BP1 in skeletal muscle may serve as an important conduit through which mTORC1 controls metabolism. PMID:26121750
Patterns and age distribution of ground-water flow to streams
Modica, E.; Reilly, T.E.; Pollock, D.W.
1997-01-01
Simulations of ground-water flow in a generic aquifer system were made to characterize the topology of ground-water flow in the stream subsystem and to evaluate its relation to deeper ground-water flow. The flow models are patterned after hydraulic characteristics of aquifers of the Atlantic Coastal Plain and are based on numerical solutions to three-dimensional, steady-state, unconfined flow. The models were used to evaluate the effects of aquifer horizontal-to-vertical hydraulic conductivity ratios, aquifer thickness, and areal recharge rates on flow in the stream subsystem. A particle tracker was used to determine flow paths in a stream subsystem, to establish the relation between ground-water seepage to points along a simulated stream and its source area of flow, and to determine ground-water residence time in stream subsystems. In a geometrically simple aquifer system with accretion, the source area of flow to streams resembles an elongated ellipse that tapers in the downgradient direction. Increased recharge causes an expansion of the stream subsystem. The source area of flow to the stream expands predominantly toward the stream headwaters. Baseflow gain is also increased along the reach of the stream. A thin aquifer restricts ground-water flow and causes the source area of flow to expand near stream headwaters and also shifts the start-of-flow to the drainage basin divide. Increased aquifer anisotropy causes a lateral expansion of the source area of flow to streams. Ground-water seepage to the stream channel originates both from near- and far-recharge locations. The range in the lengths of flow paths that terminate at a point on a stream increase in the downstream direction. Consequently, the age distribution of ground water that seeps into the stream is skewed progressively older with distance downstream. Base flow ia an integration of ground water with varying age and potentially different water quality, depending on the source within the drainage basin
NewAge: a semi-distributed hydrological model as a dynamical system, and something more.
NASA Astrophysics Data System (ADS)
Rigon, Riccardo; Franceschi, Silvia; Antonello, Andrea; Endrizzi, Stefano; Formetta, Giuseppe
2010-05-01
We describe and analyse the performances of the semi-distributed hydrological model NewAGE. This model itself is made-up of five main parts: the radiation budget estimation, the snow modelling, the evapotranspiration part, the hillslope runoff budget and the runoff aggregation in the river network, and finally the flood propagation. The model concept is based on the idea the elementary units are the hillslopes for each one the model gives the estimates of the prognostic simulated variables (one estimate for variable). Each "hillslope" does not need to coincide to the real hillslope, and can actually cover a small basin, up to some square kilometres. It constitutes the elementary "grid" element of the model. Each "hillslope" is connected to the others by the channel network. In turn, this is represented by an oriented graph, whose links are numbered through a generalisation of the Pfafstetter ordering. The topological partition of the basin is performed by a proper set of tools in JGrass. The mass budget for each hillslope is performed according to a suitable modification of Duffy (1996) dynamical model of hillslope runoff. Discharge in each link of the river network is evaluated according to Cuencas (2005). Radiation is calculated accounting for the sub-hillslope-variability in accord to a suitable scheme described in this contribution. Evapotranspiration estimation uses the Penman-Monteith formula, and includes hillslope variability in land use, soil cover and hydrological state. Flood wave propagation for the main streams can be estimated with a solver of the 1D de Saint Venant equation. Snow is modelled by a custom implementation of the Utah Energy Balance concepts. This model can simulate all the parts of the hydrological cycle, but besides being also a model of the physical processes, it also implements the infrastructure dealing with human works and reservoirs. These modelling parts are supported by appropriate ancillary modules for the treatment of the
NASA Astrophysics Data System (ADS)
Zouhri, Lahcen
In the arid countries, aquifers are increasingly exploited due to important water needs in drinky water, agriculture and industry activities. Several cities (Rabat, Kenitra, Casablanca) are alimented by the groundwater of the Mamora basin. It is located between two domains: the Rif Cordillera locate at the north and the Meseta at the south. The Mamora basin is limited to the east by Beht river, to the north by the Rharb basin, to the south by the city of Tiflet and to the west by Atlantic Ocean. The Mamora aquifer is constituted by the Plio-Quaternary sequences resting on the Miocene basement (blues marls). The objective of this study is to identify the different aquifers, determine the distribution of the physico-chemical parameters and the factors controlling this repartition. The collected data allow to determine the global minerelization, which is characterized by a variable electrical conductivity (between 595 and 2930 mS.cm-1), whose spatial distribution underlines a partition of the groundwater in three sectors where the mineralization is strong. The correlation between the chemical parameters and the electrical conductivity is generally good. It reveals the probability of a salt water intrusion.
NASA Astrophysics Data System (ADS)
Wang, Pengbo; Gao, Yuan; Chen, Xiao; Li, Ting
2016-03-01
Low-level light therapy (LLLT) has been clinically applied. Recently, more and more cases are reported with positive therapeutic effect by using transcranial light emitting diodes (LEDs) illumination. Here, we developed a LLLT helmet for treating brain injuries based on LED arrays. We designed the LED arrays in circle shape and assembled them in multilayered 3D printed helmet with water-cooling module. The LED arrays can be adjust to touch the head of subjects. A control circuit was developed to drive and control the illumination of the LLLT helmet. The software portion provides the control of on and off of each LED arrays, the setup of illumination parameters, and 3D distribution of LLLT light dose in human subject according to the illumination setups. This LLLT light dose distribution was computed by a Monte Carlo model for voxelized media and the Visible Chinese Human head dataset and displayed in 3D view at the background of head anatomical structure. The performance of the whole system was fully tested. One stroke patient was recruited in the preliminary LLLT experiment and the following neuropsychological testing showed obvious improvement in memory and executive functioning. This clinical case suggested the potential of this Illumination-parameter adjustable and illuminationdistribution visible LED helmet as a reliable, noninvasive, and effective tool in treating brain injuries.
Rosen, I G; Luczak, Susan E; Weiss, Jordan
2014-03-15
We develop a blind deconvolution scheme for input-output systems described by distributed parameter systems with boundary input and output. An abstract functional analytic theory based on results for the linear quadratic control of infinite dimensional systems with unbounded input and output operators is presented. The blind deconvolution problem is then reformulated as a series of constrained linear and nonlinear optimization problems involving infinite dimensional dynamical systems. A finite dimensional approximation and convergence theory is developed. The theory is applied to the problem of estimating blood or breath alcohol concentration (respectively, BAC or BrAC) from biosensor-measured transdermal alcohol concentration (TAC) in the field. A distributed parameter model with boundary input and output is proposed for the transdermal transport of ethanol from the blood through the skin to the sensor. The problem of estimating BAC or BrAC from the TAC data is formulated as a blind deconvolution problem. A scheme to identify distinct drinking episodes in TAC data based on a Hodrick Prescott filter is discussed. Numerical results involving actual patient data are presented.
Distribution of Hydrothermal Activity at the Lau ISS: Possible Controlling Parameters
NASA Astrophysics Data System (ADS)
Martinez, F.; Baker, E. T.; Resing, J. A.; Edwards, M. H.; Walker, S. L.; Buck, N.
2008-12-01
Seismic tomographic studies of intermediate to fast spreading rate mid-ocean ridges (MORs) interpret zones of rapid crustal cooling a few (3-4) km off axis surrounding the axial seismic low velocity zone (LVZ). These zones of rapid cooling also broadly correlate with the initiation and growth of large abyssal hill faults. The close association of both high thermal gradients and development of fault permeability at crustal scales suggests the hypothesis that these areas may be favorable locations for off-axis high temperature hydrothermal activity. In March-May 2008 on R/V Kilo Moana we conducted a near-bottom sidescan sonar and oceanographic survey along the Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) in the Lau back-arc basin to map the distribution of hydrothermal activity within this region. The survey utilized the deep-towed DSL120A (IMI120) sonar, an array of miniature autonomous plume recorders (MAPRs) attached to the tow cable and tethered beneath the sonar's depressor weight, an in situ chemical scanner (VISA) and 23 CTD hydrocasts (see Baker et al., this session). At the ELSC the survey spanned ~100 x 10 km area encompassing the ABE, Tow Cam and Kilo Moana vent fields with ~ 1 km spaced lines overall and ~500 m spaced lines in the area of the ABE vent field. On the VFR the survey spanned a distance of ~100 km along axis by ~5 km across axis with 700 m spaced lines encompassing the Vai Lili, Mariner and Tui Malila vent sites. Initial results identified particle plumes, indicative of high temperature venting, only within about a km of the ridge axis at the ELSC and VFR with possible diffuse venting indicated by MAPR oxidation-reduction potential (ORP) measurements at flank sites at VFR. The expanded sonar coverage better defines the volcano-tectonic context of the hydrothermal signals and previously mapped vent sites. Initial results suggest, however, no high-T venting more than about 1 km from the ridge axis, an apparently negative test of
Crews, D H
2006-01-01
To estimate adjustment factors and genetic parameters for gestation length (GES), AI and calving date records (n = 40,356) were extracted from the Canadian Charolais Association field database. The average time from AI to calving date was 285.2 d (SD = 4.49 d) and ranged from 274 to 296 d. Fixed effects were sex of calf, age of dam (2, 3, 4, 5 to 10, > or = 11 yr), and gestation contemporary group (year of birth x herd of origin). Variance components were estimated using REML and 4 animal models (n = 84,332) containing from 0 to 3 random maternal effects. Model 1 (M1) contained only direct genetic effects. Model 2 (M2) was G1 plus maternal genetic effects with the direct x maternal genetic covariance constrained to zero, and model 3 (M3) was G2 without the covariance constraint. Model 4 (M4) extended G3 to include a random maternal permanent environmental effect. Direct heritability estimates were high and similar among all models (0.61 to 0.64), and maternal heritability estimates were low, ranging from 0.01 (M2) to 0.09 (M3). Likelihood ratio tests and parameter estimates suggested that M4 was the most appropriate (P < 0.05) model. With M4, phenotypic variance (18.35 d2) was partitioned into direct and maternal genetic, and maternal permanent environmental components (hd2 = 0.64 +/- 0.04, hm2 = 0.07 +/- 0.01, r(d,m) = -0.37 +/- 0.06, and c2 = 0.03 +/- 0.01, respectively). Linear contrasts were used to estimate that bull calves gestated 1.26 d longer (P < 0.02) than heifers, and adjustments to a mature equivalent (5 to 10 yr old) age of dam were 1.49 (P < 0.01), 0.56 (P < 0.01), 0.33 (P < 0.01), and -0.24 (P < 0.14) d for GES records of calves born to 2-, 3-, 4-, and > or = 11-yr-old cows, respectively. Bivariate animal models were used to estimate genetic parameters for GES with birth and adjusted 205-d weaning weights, and postweaning gain. Direct GES was positively correlated with direct birth weight (BWT; 0.34 +/- 0.04) but negatively correlated with maternal
Crater size-frequency distribution measurements and age of the Compton-Belkovich Volcanic Complex
NASA Astrophysics Data System (ADS)
Shirley, K. A.; Zanetti, M.; Jolliff, B.; van der Bogert, C. H.; Hiesinger, H.
2016-07-01
The Compton-Belkovich Volcanic Complex (CBVC) is a 25 × 35 km feature on the lunar farside marked by elevated topography, high albedo, high thorium concentration, and high silica content. Morphologies indicate that the complex is volcanic in origin and compositions indicate that it represents rare silicic volcanism on the Moon. Constraining the timing of silicic volcanism at the complex is necessary to better understand the development of evolved magmas and when they were active on the lunar surface. We employ image analysis and crater size-frequency distribution (CSFD) measurements on several locations within the complex and at surrounding impact craters, Hayn (87 km diameter), and Compton (160 km diameter), to determine relative and absolute model ages of regional events. Using CSFD measurements, we establish a chronology dating regional resurfacing events and the earliest possible onset of CBVC volcanism at ∼3.8 Ga, the formation of Compton Crater at 3.6 Ga, likely resurfacing by volcanism at the CBVC at ∼3.5 Ga, and the formation of Hayn Crater at ∼1 Ga. For the CBVC, we find the most consistent results are obtained using craters larger than 300 m in diameter; the small crater population is affected by their approach to an equilibrium condition and by the physical properties of regolith at the CBVC.
Recent changes in earnings distributions in the United States: age and cohort effects.
Utendorf, K R
1999-01-01
In this article, the author uses large, Social Security administrative data sets to examine changes in earnings distributions in the United States over the 1980s through the mid-1990s. Because the earnings information contained in these data sets comes directly from the W-2 forms field by employers, self-reporting errors and top-coding problems, common in other data used for this type of analysis, are minimized. Previous research has documented an increase in overall earnings inequality during the 1970s and the 1980s. The author finds that this upward trend in overall earnings inequality continues into the mid-1990s, despite a period of nearly constant or slightly decreasing earnings inequality from 1988 through 1992. The data also suggest that between-group earnings inequality, whether dividing the sample into groups by age group or by birth cohort, is increasing. Despite the increase in between-group earnings inequality over the period examined, however, within-group earnings inequality remains by far the largest contributor to overall earnings inequality.
Jenderka, Klaus-Vitold; Koch, Christian
2006-12-22
Ultrasound cleaning baths fitting the full range from micromechanical components up to large machine parts, are regularly used in industry and in the lab. Despite the large number of applications, generally approved principles and objective criteria for parameter settings which allow an efficient operation are non-existent. The empirical selections of the running parameters often impede an optimization in terms of produce and reproducibility. One proposal for an objective description of the processes is the characterization of the sound field in the cleaning bath, which causes cavities, and subsequently, the cleaning process. Sound field measurements in the appropriate frequency range from 20kHz up to more then 1MHz incorporate a number of problems, such as large sensors disturbing the sound field, a lack of accuracy and the risk of being destroyed by cavitation bubbles. Measurement systems based on optical fiber tips and piezo-electrical hydrophones will be presented, which fulfil the accuracy requirements and withstand ultrasound fields with high power and cavitation. The spatial distribution of sound field parameters such as positive and negative peak pressure, amplitudes of fundamentals, harmonics and sub-harmonics as well as the energy density and spectral density in several frequency ranges are determined in experiments. Finally, the determined field parameters are related to the cavitation effects by means of photometric analysis of perforated aluminium foil. Perforations as well as intentions are analyzed and quantified from scanner images of the exposed foil samples using special image processing software. The experiments indicate clear differences in the structure of the sound fields and the spectral properties between the several types of cleaning baths, transducer arrangements and excitations.
Smerieri, Arianna; Testa, Chiara; Lazzeroni, Pietro; Nuti, Francesca; Grossi, Enzo; Cesari, Silvia; Montanini, Luisa; Latini, Giuseppe; Bernasconi, Sergio; Papini, Anna Maria; Street, Maria E.
2015-01-01
Objectives Phthalates might be implicated with obesity and insulin sensitivity. We evaluated the levels of primary and secondary metabolites of Di-(2-ethylhexyl) phthalate (DEHP) in urine in obese and normal-weight subjects both before and during puberty, and investigated their relationships with auxological parameters and indexes of insulin sensitivity. Design and Methods DEHP metabolites (MEHP, 6-OH-MEHP, 5-oxo-MEHP, 5-OH-MEHP, and 5-CX-MEHP), were measured in urine by RP-HPLC-ESI-MS. Traditional statistical analysis and a data mining analysis using the Auto-CM analysis were able to offer an insight into the complex biological connections between the studied variables. Results The data showed changes in DEHP metabolites in urine related with obesity, puberty, and presence of insulin resistance. Changes in urine metabolites were related with age, height and weight, waist circumference and waist to height ratio, thus to fat distribution. In addition, clear relationships in both obese and normal-weight subjects were detected among MEHP, its products of oxidation and measurements of insulin sensitivity. Conclusion It remains to be elucidated whether exposure to phthalates per se is actually the risk factor or if the ability of the body to metabolize phthalates is actually the key point. Further studies that span from conception to elderly subjects besides further understanding of DEHP metabolism are warranted to clarify these aspects. PMID:25706863
NASA Astrophysics Data System (ADS)
Silvestro, F.; Gabellani, S.; Rudari, R.; Delogu, F.; Laiolo, P.; Boni, G.
2015-04-01
During the last decade the opportunity and usefulness of using remote-sensing data in hydrology, hydrometeorology and geomorphology has become even more evident and clear. Satellite-based products often allow for the advantage of observing hydrologic variables in a distributed way, offering a different view with respect to traditional observations that can help with understanding and modeling the hydrological cycle. Moreover, remote-sensing data are fundamental in scarce data environments. The use of satellite-derived digital elevation models (DEMs), which are now globally available at 30 m resolution (e.g., from Shuttle Radar Topographic Mission, SRTM), have become standard practice in hydrologic model implementation, but other types of satellite-derived data are still underutilized. As a consequence there is the need for developing and testing techniques that allow the opportunities given by remote-sensing data to be exploited, parameterizing hydrological models and improving their calibration. In this work, Meteosat Second Generation land-surface temperature (LST) estimates and surface soil moisture (SSM), available from European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) H-SAF, are used together with streamflow observations (S. N.) to calibrate the Continuum hydrological model that computes such state variables in a prognostic mode. The first part of the work aims at proving that satellite observations can be exploited to reduce uncertainties in parameter calibration by reducing the parameter equifinality that can become an issue in forecast mode. In the second part, four parameter estimation strategies are implemented and tested in a comparative mode: (i) a multi-objective approach that includes both satellite and ground observations which is an attempt to use different sources of data to add constraints to the parameters; (ii and iii) two approaches solely based on remotely sensed data that reproduce the case of a scarce data
NASA Astrophysics Data System (ADS)
Alexander, P.; Luna, D.; de la Torre, A.; Schmidt, T.
2015-08-01
The number of gravity wave (GW) activity climatologies in the stratosphere started to increase more than 10 years ago since the appearance of large amounts of limb and nadir satellite sounders data. There have been very few discussions regarding the adequate statistical description of GW activity in terms of a distribution function and its parameters. We put forward the question whether a general statistical functional representation adaptable to the characteristics of GW activity in diverse geographic regions and seasons exists. Here we approach this issue for two different types of limb sounders and in particular we try to find out which parameters may represent at best the climatological features. We study results for a region close to the Patagonian Andes and their prolongation in the Antarctic Peninsula, which is well-known for the generation by topography of intense stratospheric GW, specially during winter and spring. Global Positioning System (GPS) radio occultation (RO) records presently provide over 2000 profiles per day. We used 5 years of COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) mission GPS RO data, which supplied almost 150,000 retrievals for our study. Three different distribution functions have been approached to describe the GW activity climatologies: gaussian, log-normal and gamma. The latter function has not been used in previous work. It has been shown here that it is a competitive option to the log-normal distribution. In addition, its use allows not only to quantify the GW activity level of each climatology in the stratosphere, but also to find out the number of significant modes that essentially determine it. Alternative parameters to the mean like the median may be used to characterize the climatologies. The use of the median may exhibit advantages in cases where the presence of spurious large GW activity measurements are suspected in GPS RO data. The mean is equally suitable to establish GW activity
NASA Astrophysics Data System (ADS)
Broz, Miroslav; Durech, Josef; Hanus, Josef; Lehky, Martin
2014-11-01
In our recent work (Hanus et al. 2013) we studied dynamics of asteroid families constrained by the distribution of pole latitudes vs semimajor axis. The model contained the following ingredients: (i) the Yarkovsky semimajor-axis drift, (ii) secular spin evolution due to the YORP effect, (iii) collisional reorientations, (iv) a simple treatment of spin-orbit resonances and (v) of mass shedding.We suggest to use a different complementary approach, based on distribution functions of shape parameters. Based on ~1000 old and new convex-hull shape models, we construct the distributions of suitable quantities (ellipticity, normalized facet areas, etc.) and we discuss differences among asteroid populations. We also check for outlier points which may then serve as a possible identification of (large) interlopers among "real" family members.This has also implications for SPH models of asteroid disruptions which can be possibly further constrained by the shape models of resulting fragments. Up to now, the observed size-frequency distribution and velocity field were used as constraints, sometimes allowing for a removal of interlopers (Michel et al. 2011).We also describe ongoing observations by the ProjectSoft robotic observatory called "Blue Eye 600", which supports our efforts to complete the sample of shapes for a substantial fraction of (large) family members. Dense photometry is targeted in such a way to maximize a possibility to derive a new pole/shape model.Other possible applications of the observatory include: (i) fast resolved observations of fireballs (thanks to a fast-motion capability, up to 90 degrees/second), or (ii) an automatic survey of a particular population of objects (MBAs, NEAs, variable stars, novae etc.)Acknowledgements: This work was supported by the Technology Agency of the Czech Republic (grant no. TA03011171) and Czech Science Foundation (grant no. 13-01308S).
NASA Astrophysics Data System (ADS)
Dalkilic, Turkan Erbay; Apaydin, Aysen
2009-11-01
In a regression analysis, it is assumed that the observations come from a single class in a data cluster and the simple functional relationship between the dependent and independent variables can be expressed using the general model; Y=f(X)+[epsilon]. However; a data cluster may consist of a combination of observations that have different distributions that are derived from different clusters. When faced with issues of estimating a regression model for fuzzy inputs that have been derived from different distributions, this regression model has been termed the [`]switching regression model' and it is expressed with . Here li indicates the class number of each independent variable and p is indicative of the number of independent variables [J.R. Jang, ANFIS: Adaptive-network-based fuzzy inference system, IEEE Transaction on Systems, Man and Cybernetics 23 (3) (1993) 665-685; M. Michel, Fuzzy clustering and switching regression models using ambiguity and distance rejects, Fuzzy Sets and Systems 122 (2001) 363-399; E.Q. Richard, A new approach to estimating switching regressions, Journal of the American Statistical Association 67 (338) (1972) 306-310]. In this study, adaptive networks have been used to construct a model that has been formed by gathering obtained models. There are methods that suggest the class numbers of independent variables heuristically. Alternatively, in defining the optimal class number of independent variables, the use of suggested validity criterion for fuzzy clustering has been aimed. In the case that independent variables have an exponential distribution, an algorithm has been suggested for defining the unknown parameter of the switching regression model and for obtaining the estimated values after obtaining an optimal membership function, which is suitable for exponential distribution.
NASA Astrophysics Data System (ADS)
Lautenschläger, T.; Feder, R.; Neumann, H.; Rice, C.; Schubert, M.; Bundesmann, C.
2016-10-01
In the present study, the influence of ion energy and geometrical parameters onto the angular and energy distribution of secondary particles for sputtering a Ti target with Ar ions is investigated. The angular distribution of the particle flux of the sputtered Ti atoms was determined by the collection method, i.e. by growing Ti films and measuring their thickness. The formal description of the particle flux can be realized by dividing it into an isotropic and an anisotropic part. The experimental data show that increasing the ion energy or decreasing the ion incidence angle lead to an increase of the isotropic part, which is in good agreement with basic sputtering theory. The energy distribution of the secondary ions was measured using an energy-selective mass spectrometer. The energy distribution of the sputtered target ions shows a maximum at an energy between 10 eV and 20 eV followed by a decay proportional to E-n, which is in principle in accordance with Thompson's theory, followed by a high energetic tail. When the sum of incidence angle and emission angle is increased, the high-energetic tail expands to higher energies and an additional peak due to direct sputtering events may occur. In the case of backscattered primary Ar ions, a maximum at an energy between 5 eV and 10 eV appears and, depending on the scattering geometry, an additional broad peak at a higher energy due to direct scattering events is observed. The center energy of the additional structure shifts systematically to higher energies with decreasing scattering angle or increasing ion energy. The experimental results are compared to calculations based on simple elastic two-particle-interaction theory and to simulations done with the Monte Carlo code SDTrimSP. Both confirm in principle the experimental findings.
Zakari, Friday Ocheja; Ayo, Joseph Olusegun; Rekwot, Peter Ibrahim; Kawu, Mohammed Umar
2015-12-01
The aim of the study was to investigate the effects of age and season on haematological parameters of donkeys at rest during the rainy and cold-dry seasons. Thirty healthy donkeys divided into three groups based on their age served as the subjects. During each season, blood sample was collected from each donkey thrice, 2 weeks apart, for haematological analysis, and the dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) were obtained thrice each day during the experimental period using standard procedures. During the rainy season, the mean DBT (33.05 ± 0.49 °C), RH (73.63 ± 1.09 %) and THI (84.39 ± 0.71) were higher (P < 0.0001) than the corresponding values of 24.00 ± 0.44 °C, 36.80 ± 0.92 % and 64.80 ± 0.62, during the cold-dry season. Packed cell volume (PCV), erythrocyte count [red blood cell (RBC)], haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), platelet count (PLT), leucocyte count [white blood cell (WBC)], lymphocyte count (LYM) and neutrophil/lymphocyte ratio (N/L) were higher (P < 0.05) in adults than foals during the rainy season. The MCV, MCH, WBC, NEU, LYM and PLT of adult and yearling donkeys were higher (P < 0.05) during the rainy than the cold-dry season. The PCV, RBC, Hb, MCV, MCH, and NEU of foals were higher in the rainy than the cold-dry season. The N/L of adult and foal donkeys were higher (P < 0.05) in the rainy than in the cold-dry season. In conclusion, PCV, RBC, Hb and LYM were considerably higher in foals than yearlings or adults during the rainy season, while erythrocytic indices and platelet counts were higher in adults or yearlings than in foals in both seasons. Erythrocytic indices, PLT and N/L were higher in the rainy than the cold-dry season in adults, yearlings and foals.
NASA Astrophysics Data System (ADS)
Zakari, Friday Ocheja; Ayo, Joseph Olusegun; Rekwot, Peter Ibrahim; Kawu, Mohammed Umar
2015-12-01
The aim of the study was to investigate the effects of age and season on haematological parameters of donkeys at rest during the rainy and cold-dry seasons. Thirty healthy donkeys divided into three groups based on their age served as the subjects. During each season, blood sample was collected from each donkey thrice, 2 weeks apart, for haematological analysis, and the dry-bulb temperature (DBT), relative humidity (RH) and temperature-humidity index (THI) were obtained thrice each day during the experimental period using standard procedures. During the rainy season, the mean DBT (33.05 ± 0.49 °C), RH (73.63 ± 1.09 %) and THI (84.39 ± 0.71) were higher ( P < 0.0001) than the corresponding values of 24.00 ± 0.44 °C, 36.80 ± 0.92 % and 64.80 ± 0.62, during the cold-dry season. Packed cell volume (PCV), erythrocyte count [red blood cell (RBC)], haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), platelet count (PLT), leucocyte count [white blood cell (WBC)], lymphocyte count (LYM) and neutrophil/lymphocyte ratio (N/L) were higher ( P < 0.05) in adults than foals during the rainy season. The MCV, MCH, WBC, NEU, LYM and PLT of adult and yearling donkeys were higher ( P < 0.05) during the rainy than the cold-dry season. The PCV, RBC, Hb, MCV, MCH, and NEU of foals were higher in the rainy than the cold-dry season. The N/L of adult and foal donkeys were higher ( P < 0.05) in the rainy than in the cold-dry season. In conclusion, PCV, RBC, Hb and LYM were considerably higher in foals than yearlings or adults during the rainy season, while erythrocytic indices and platelet counts were higher in adults or yearlings than in foals in both seasons. Erythrocytic indices, PLT and N/L were higher in the rainy than the cold-dry season in adults, yearlings and foals.
Lenzi, Andrea
2014-01-01
Metabolic and hormonal modifications after long-term testosterone (T) treatment have never been investigated. 20 hypogonadal men (mean T = 241 ng/dL–8.3 nmol/L) with metabolic syndrome (MS, mean age 58) were treated with T-undecanoate injections every 12 weeks for 60 months. 20 matched subjects in whom T was unaccepted or contraindicated served as controls. Primary endpoints were variations from baseline of metabolic and hormonal parameters. In T-group, significant reductions in waist circumference (−9.6 ± 3.8 cm, P < 0.0001), body weight (−15 ± 2.8 Kg, P < 0.0001), and glycosylated hemoglobin (−1.6 ± 0.5%, P < 0.0001) occurred, along with improvements in insulin sensitivity (HOMA-I; −2.8 ± 0.6, P < 0.0001), lipid profile (total/HDL-cholesterol ratio −2.9 ± 1.5, P < 0.0001), systolic and diastolic blood pressure (−23 ± 10 and −16 ± 8 mm Hg, P < 0.0001, resp.), and neck and lumbar T-scores (+0.5 ± 0.15 gr/cm2, P < 0.0001; +0.7 ± 0.8, P < 0.0001, resp.). Also, serum vitamin D (+14.0 ± 1.3 ng/mL, P < 0.01), TSH (− 0.9 ± 0.3 mUI/mL, P < 0.01), GH (0.74 ± 0.2 ng/mL, P < 0.0001), and IGF1 (105 ± 11 ng/mL, P < 0.01) levels changed in T-group but not in controls. Normalization of T levels in men with MS improved obesity, glycemic control, blood pressure, lipid profile, and bone mineral density compared with controls. Amelioration in hormonal parameters, that is, vitamin D, growth hormone, and thyrotropin plasma levels, were reported. PMID:24688542
Liu, Ning He, Miao; Alghamdi, Hisham; Chen, George; Fu, Mingli; Li, Ruihai; Hou, Shuai
2015-08-14
Trapping parameters can be considered as one of the important attributes to describe polymeric materials. In the present paper, a more accurate charge dynamics model has been developed, which takes account of charge dynamics in both volts-on and off stage into simulation. By fitting with measured charge data with the highest R-square value, trapping parameters together with injection barrier of both normal and aged low-density polyethylene samples were estimated using the improved model. The results show that, after long-term ageing process, the injection barriers of both electrons and holes is lowered, overall trap depth is shallower, and trap density becomes much greater. Additionally, the changes in parameters for electrons are more sensitive than those of holes after ageing.
NASA Astrophysics Data System (ADS)
Koffi, A. K.; Gosset, M.; Zahiri, E.-P.; Ochou, A. D.; Kacou, M.; Cazenave, F.; Assamoi, P.
2014-06-01
As part of the African Monsoon Multidisciplinary Analysis (AMMA) field campaign an X-band dual-polarization Doppler radar was deployed in Benin, West-Africa, in 2006 and 2007, together with a reinforced rain gauge network and several optical disdrometers. Based on this data set, a comparative study of several rainfall estimators that use X-band polarimetric radar data is presented. In tropical convective systems as encountered in Benin, microwave attenuation by rain is significant and quantitative precipitation estimation (QPE) at X-band is a challenge. Here, several algorithms based on the combined use of reflectivity, differential reflectivity and differential phase shift are evaluated against rain gauges and disdrometers. Four rainfall estimators were tested on twelve rainy events: the use of attenuation corrected reflectivity only (estimator R(ZH)), the use of the specific phase shift only R(KDP), the combination of specific phase shift and differential reflectivity R(KDP,ZDR) and an estimator that uses three radar parameters R(ZH,ZDR,KDP). The coefficients of the power law relationships between rain rate and radar variables were adjusted either based on disdrometer data and simulation, or on radar-gauges observations. The three polarimetric based algorithms with coefficients predetermined on observations outperform the R(ZH) estimator for rain rates above 10 mm/h which explain most of the rainfall in the studied region. For the highest rain rates (above 30 mm/h) R(KDP) shows even better scores, and given its performances and its simplicity of implementation, is recommended. The radar based retrieval of two parameters of the rain drop size distribution, the normalized intercept parameter NW and the volumetric median diameter Dm was evaluated on four rainy days thanks to disdrometers. The frequency distributions of the two parameters retrieved by the radar are very close to those observed with the disdrometer. NW retrieval based on a combination of ZH
Bundy, D A; Kan, S P; Rose, R
1988-01-01
The gastrointestinal helminth infection status of 1574 children living in a slum area of Kuala Lumpur, Malaysia was assessed by quantitative coprology. Almost two-thirds were infected with Trichuris trichiura, 49.6% with Ascaris lumbricoides, and 5.3% with hookworm. Infection prevalence rose rapidly to a stable asymptote at 7 years of age, and the age-intensity profile was convex with maximal values in the 5-10 year age classes. This pattern was the same for males and females, but differed markedly between different ethnic groups. The frequency distributions of A. lumbricoides and T. trichiura were highly overdispersed (k values were 0.21 and 0.27, respectively), and age-dependent over the 0-8 year age classes. This suggests that the force of infection with these nematodes is lower in infants than in older children.
Guarner-Lans, Verónica; Soria-Castro, Elizabeth; Torrico-Lavayen, Rocío; Patrón-Soberano, Araceli; Carvajal-Aguilera, Karla G.; Castrejón-Tellez, Vicente; Rubio-Ruiz, María Esther
2016-01-01
The role of the renin-angiotensin system (RAS) in blood pressure regulation in MS during aging is unknown. It participates in metabolic syndrome (MS) and aging regulating vascular tone and remodeling. RAS might participate in a compensatory mechanism decreasing blood pressure and allowing MS rats to reach 18 months of age and it might form part of therapeutical procedures to ameliorate MS. We studied histological changes and distribution of RAS receptors in aortas of MS aged rats. Electron microscopy images showed premature aging in MS since the increased fibrosis, enlarged endothelium, and invasion of this layer by muscle cells that was present in control 18-month-old aortas were also found in 6-month-old aortas from MS rats. AT1, AT2, and Mas receptors mediate the effects of Ang II and Ang 1-7, respectively. Fluorescence from AT2 decreased with age in control and MS aortas, while fluorescence of AT1 increased in aortas from MS rats at 6 months and diminished during aging. Mas expression increased in MS rats and remained unchanged in control rats. In conclusion, there is premature aging in the aortas from MS rats and the elevated expression of Mas receptor might contribute to decrease blood pressure during aging in MS. PMID:27293881
Guarner-Lans, Verónica; Soria-Castro, Elizabeth; Torrico-Lavayen, Rocío; Patrón-Soberano, Araceli; Carvajal-Aguilera, Karla G; Castrejón-Tellez, Vicente; Rubio-Ruiz, María Esther
2016-01-01
The role of the renin-angiotensin system (RAS) in blood pressure regulation in MS during aging is unknown. It participates in metabolic syndrome (MS) and aging regulating vascular tone and remodeling. RAS might participate in a compensatory mechanism decreasing blood pressure and allowing MS rats to reach 18 months of age and it might form part of therapeutical procedures to ameliorate MS. We studied histological changes and distribution of RAS receptors in aortas of MS aged rats. Electron microscopy images showed premature aging in MS since the increased fibrosis, enlarged endothelium, and invasion of this layer by muscle cells that was present in control 18-month-old aortas were also found in 6-month-old aortas from MS rats. AT1, AT2, and Mas receptors mediate the effects of Ang II and Ang 1-7, respectively. Fluorescence from AT2 decreased with age in control and MS aortas, while fluorescence of AT1 increased in aortas from MS rats at 6 months and diminished during aging. Mas expression increased in MS rats and remained unchanged in control rats. In conclusion, there is premature aging in the aortas from MS rats and the elevated expression of Mas receptor might contribute to decrease blood pressure during aging in MS. PMID:27293881
Napier, B.A.; Farris, W.T.; Simpson, J.C.
1992-12-01
A series of scoping calculations has been undertaken to evaluate the absolute and relative contribution of different radionuclides and exposure pathways to doses that may have been received by individuals living in the vicinity of the Hanford site. This scoping calculation (Calculation 005) examined the contributions of numerous parameters to the uncertainty distribution of doses calculated for environmental exposures and accumulation in foods. This study builds on the work initiated in the first scoping study of iodine in cow`s milk and the third scoping study, which added additional pathways. Addressed in this calculation were the contributions to thyroid dose of infants from (1) air submersion and groundshine external dose, (2) inhalation, (3) ingestion of soil by humans, (4) ingestion of leafy vegetables, (5) ingestion of other vegetables and fruits, (6) ingestion of meat, (7) ingestion of eggs, and (8) ingestion of cows` milk from Feeding Regime 1 as described in Calculation 001.
Johannesdottir, Fjola; Aspelund, Thor; Siggeirsdottir, Kristin; Jonsson, Brynjolfur Y; Mogensen, Brynjolfur; Sigurdsson, Sigurdur; Harris, Tamara B; Gudnason, Vilmundur G; Lang, Thomas F; Sigurdsson, Gunnar
2012-05-01
In a cross-sectional study we investigated the relationship between muscle and bone parameters in the mid-thigh in older people using data from a single axial computed tomographic section through the mid-thigh. Additionally, we studied the association of these variables with incident low-trauma lower limb fractures. A total of 3,762 older individuals (1,838 men and 1,924 women), aged 66-96 years, participants in the AGES-Reykjavik study, were studied. The total cross-sectional muscular area and knee extensor strength declined with age similarly in both sexes. Muscle parameters correlated most strongly with cortical area and total shaft area (adjusted for age, height, and weight) but explained <10 % of variability in those bone parameters. The increment in medullary area (MA) and buckling ratio (BR) with age was almost fourfold greater in women than men. The association between MA and muscle parameters was nonsignificant. During a median follow-up of 5.3 years, 113 women and 66 men sustained incident lower limb fractures. Small muscular area, low knee extensor strength, large MA, low cortical thickness, and high BR were significantly associated with fractures in both sexes. Our results show that bone and muscle loss proceed at different rates and with different gender patterns. PMID:22451219
Johannesdottir, Fjola; Aspelund, Thor; Siggeirsdottir, Kristin; Jonsson, Brynjolfur Y; Mogensen, Brynjolfur; Sigurdsson, Sigurdur; Harris, Tamara B; Gudnason, Vilmundur G; Lang, Thomas F; Sigurdsson, Gunnar
2012-05-01
In a cross-sectional study we investigated the relationship between muscle and bone parameters in the mid-thigh in older people using data from a single axial computed tomographic section through the mid-thigh. Additionally, we studied the association of these variables with incident low-trauma lower limb fractures. A total of 3,762 older individuals (1,838 men and 1,924 women), aged 66-96 years, participants in the AGES-Reykjavik study, were studied. The total cross-sectional muscular area and knee extensor strength declined with age similarly in both sexes. Muscle parameters correlated most strongly with cortical area and total shaft area (adjusted for age, height, and weight) but explained <10 % of variability in those bone parameters. The increment in medullary area (MA) and buckling ratio (BR) with age was almost fourfold greater in women than men. The association between MA and muscle parameters was nonsignificant. During a median follow-up of 5.3 years, 113 women and 66 men sustained incident lower limb fractures. Small muscular area, low knee extensor strength, large MA, low cortical thickness, and high BR were significantly associated with fractures in both sexes. Our results show that bone and muscle loss proceed at different rates and with different gender patterns.
NASA Astrophysics Data System (ADS)
Ames, D. P.; Osorio-Murillo, C.; Over, M. W.; Rubin, Y.
2012-12-01
The Method of Anchored Distributions (MAD) is an inverse modeling technique that is well-suited for estimation of spatially varying parameter fields using limited observations and Bayesian methods. This presentation will discuss the design, development, and testing of a free software implementation of the MAD technique using the open source DotSpatial geographic information system (GIS) framework, R statistical software, and the MODFLOW groundwater model. This new tool, dubbed MAD-GIS, is built using a modular architecture that supports the integration of external analytical tools and models for key computational processes including a forward model (e.g. MODFLOW, HYDRUS) and geostatistical analysis (e.g. R, GSLIB). The GIS-based graphical user interface provides a relatively simple way for new users of the technique to prepare the spatial domain, to identify observation and anchor points, to perform the MAD analysis using a selected forward model, and to view results. MAD-GIS uses the Managed Extensibility Framework (MEF) provided by the Microsoft .NET programming platform to support integration of different modeling and analytical tools at run-time through a custom "driver." Each driver establishes a connection with external programs through a programming interface, which provides the elements for communicating with core MAD software. This presentation gives an example of adapting the MODFLOW to serve as the external forward model in MAD-GIS for inferring the distribution functions of key MODFLOW parameters. Additional drivers for other models are being developed and it is expected that the open source nature of the project will engender the development of additional model drivers by 3rd party scientists.
NASA Astrophysics Data System (ADS)
Lolli, B.; Gasperini, P.
We analyzed the available instrumental catalogs of Italian earthquakes from 1960 to 1996 to compute the parameters of the time-magnitude distribution model proposed by Reasenberg e Jones (1989, 1994) and currently used to make aftershock predictions in California. We found that empirical corrections ranging from 0.3 (before 1976) to 0.5 magnitude units (between 1976 and 1980) are necessary to make the dataset ho- mogeneous over the entire period. The estimated model parameters result quite stable with respect to mainshock magnitude and sequence detection algorithm, while their spatial variations suggest that regional estimates might predict the behavior of future sequences better than ones computed by the whole Italian dataset. In order to improve the goodness of fit for sequences including multiple mainshocks (like the one occurred in Central Italy from September 1997 to May 1998) we developed a quasi epidemic model (QETAS) consisting of the superposition of a small number of Omori's pro- cesses originated by strong aftershocks. We found that the inclusion in the QETAS model of the shocks with magnitude larger than mainshock magnitude minus one (that are usually located and sized in near real-time by the observatories) improves significantly the ability of the algorithm to predict the sequence behaviors.
NASA Astrophysics Data System (ADS)
Silvestro, F.; Gabellani, S.; Rudari, R.; Delogu, F.; Laiolo, P.; Boni, G.
2014-06-01
During the last decade the opportunity and usefulness of using remote sensing data in hydrology, hydrometeorology and geomorphology has become even more evident and clear. Satellite based products often provide the advantage of observing hydrologic variables in a distributed way while offering a different view that can help to understand and model the hydrological cycle. Moreover, remote sensing data are fundamental in scarce data environments. The use of satellite derived DTM, which are globally available (e.g. from SRTM as used in this work), have become standard practice in hydrologic model implementation, but other types of satellite derived data are still underutilized. In this work, Meteosat Second Generation Land Surface Temperature (LST) estimates and Surface Soil Moisture (SSM) available from EUMETSAT H-SAF are used to calibrate the Continuum hydrological model that computes such state variables in a prognostic mode. This work aims at proving that satellite observations dramatically reduce uncertainties in parameters calibration by reducing their equifinality. Two parameter estimation strategies are implemented and tested: a multi-objective approach that includes ground observations and one solely based on remotely sensed data. Two Italian catchments are used as the test bed to verify the model capability in reproducing long-term (multi-year) simulations.
Guo, D G; Hao, Y Z; Li, H Y; Fang, C Q; Sun, L J; Zhu, H; Wang, J; Huang, X F; Ni, P F; Xu, K W
2013-10-01
Stoichiometric strontium-incorporated hydroxyapatite (Sr-HA) with different Sr concentrations [Sr/(Sr+Ca)] were synthesized using a wet chemical approach and characterized by X-ray diffraction, Fourier-transformed infrared absorption, X-ray photoelectron spectroscopy, and Rietveld Structure Refinement. The crystal lattice parameter, Sr distribution, chemical state of Sr, and also the relationships between their variations and the Sr concentrations have been intensively studied. The results show that both the crystal lattice parameters and crystal plane space of Sr-HA remarkably increase with the Sr concentration increasing. Whether Sr preferably occupies the Ca(I) site or Ca(II) site after incorporated into apatite lattice depends on the Sr number incorporated into apatite. All the Sr ions completely occupy the Ca(II) sites when the Sr concentration is below 5%. With the exception of partial Sr ions occupying the Ca(II) sites, the other Sr ions start to occupy the Ca(I) sites when the Sr concentration doped in HA is beyond 10%. The ratio of Sr ions occupying the Ca(I) sites increases with the further raising Sr concentration up to 20%. The Sr ions inherit the chemical state and environment of the original Ca(I) or Ca(II) site after incorporated into apatite. PMID:23661409
Viaud, B.F.; Kozanecki, W.; O'Grady, C.; Thompson, J.; Weaver, M.; /SLAC
2006-07-28
The 3-D luminosity distribution at the IP of the SLAC B-Factory is monitored using e{sup +}e{sup -} {yields} e{sup +}e{sup -}, {mu}{sup +}{mu}{sup -} events reconstructed online in the BABAR detector. The transverse centroid and spatial orientation of the luminosity ellipsoid reliably monitor IP orbit drifts. The longitudinal centroid is sensitive to small variations in the average relative RF phase of the beams and provides a detailed measurement of the phase transient along the bunch train. The longitudinal luminosity distribution depends on the e{sup +,-} overlap bunch length and the vertical IP {beta}-functions. Relative variations in horizontal luminous size are detectable at the micron level. In addition to continuous on-line monitoring of all the parameters above, we performed detailed studies of their variation along the bunch train to investigate a temporary luminosity degradation. We also compare {beta}*{sub y} measurements, collected over a year of high-luminosity operation, with HER and LER lattice functions measured by resonant transverse excitation. Our bunch-length measurements are consistent with those obtained by other methods and provide direct evidence for bunch-length modulation.
Parízková, J; Vĕtvicka, J; Pousek, L; Liska, O
1995-06-28
BACKGROUND. In middle-aged and elderly men the cardiovascular mortality in this country is still relatively high. The objective of the presented work was therefore the validation of simple parameters of fat deposition as a risk factor in order to select subjects at risk where preventive measures are called for. METHODS AND RESULTS. In 68 men aged 43.8 +/- 7.4 years from a sample of managers of a Prague bank the case-history we evaluated, as well as a basic physical examination, a loading test on a bicycle ergometer (performance evaluated in W/kg body weight or lean body mass) and ECG; serum lipids were examined (total and HDL-cholesterol, triacyglycerols), the body mass index (BMI), the ratio of depot fat (by evaluation of 10 skinfolds measured by means of a caliper) and the distribution of body fat (indices relating either only the subscapular and tricipital skinfold or all skinfolds on the trunk to all skinfolds on the extremities, and the waist/hip ratio). The basic physical examination did not reveal any serious acute diseases. Mean BMI values (26.7 +/- 3.4 kg/m2) and body fat ratio (20.8 +/- 4.2%) were higher than standard values. 24.1% of the men were obese, the W/H ratio was 0.9 +/- 0.1 but this index, similarly as the other mentioned indices, were elevated, indicating risk. The mean values of the heart rate and blood pressure at rest and after a load were normal, however 11.5% of the men had an elevated diastolic pressure after a load and a similar percentage of men manifested during a load certain signs of myocardial ischaemia. The prevalence of hypertension according to WHO criteria was 9.6%. On average, however, the physical performance (W/kg of the total body weight or lean body mass) was 108% of the Czech standard assessed previously within the framework of the International Biological Programme. The total cholesterol was 5.35 +/- 1.04, HDL 1.11 +/- 0.19, total triacylglycerols 1.81 +/- 0.77 mmol/l. The ratio of total and HDL cholesterol was 4.9 +/- 1
Distribution of age-related thymulin titres in normal subjects through the course of life
Consolini, R; Legitimo, A; Calleri, A; Milani, M
2000-01-01
The thymus has a dominant immunological role in utero and in early childhood, being a primary source of T lymphopoiesis, and its investigation may be particularly relevant for the immunological study of paediatric patients. Thymulin, a nonapeptide secreted by the thymus, is an essential hormone for T lymphocyte differentiation and function. As thymulin values in the normal population have not been well documented, especially for children under the age of 1 year, we detail thymic endocrine function by presenting age-related plasma thymulin levels in a large series (n = 93) of healthy individuals, ranging from birth to old age. We demonstrate that thymulin is already detectable at birth; it then gradually increases with age, reaching the highest level in children aged 5–10 years. Starting at adolescence, thymulin titres gradually start to fall, reaching the lowest value at 36 years of age and remaining steady until 80 years (the oldest person tested). PMID:10971509
ERIC Educational Resources Information Center
Yamamoto, Kentaro; Muraki, Eiji
The extent to which properties of the ability scale and the form of the latent trait distribution influence the estimated item parameters of item response theory (IRT) was investigated using real and simulated data. Simulated data included 5,000 ability values randomly drawn from the standard normal distribution. Real data included the results for…
Seo, Dae Yun; Lee, Sungryul; Figueroa, Arturo; Kwak, Yi Sub; Kim, Nari; Rhee, Byoung Doo; Ko, Kyung Soo; Bang, Hyun Seok; Baek, Yeong Ho; Han, Jin
2012-12-01
Aged garlic extract (AGE) is known to have a protective effect against immune system, endothelial function, oxidative stress and inflammation. We examined the effects of exercise with and without aged garlic extract administration on body weight, lipid profiles, inflammatory cytokines, and oxidative stress marker in high-fat diet (HFD)-induced obese rats. Forty-five Sprague-Dawley rats were fed either a HFD (HFD, n = 40) or a normal diet (ND, n = 5) for 6 weeks and thereafter randomized into ND (n = 5), HFD (n = 10), HFD with AGE (n = 10), HFD with Exercise (n = 10), or HFD with Exercise+AGE (n = 10) for 4 weeks. AGE groups were administered at a dose of 2.86 g/kg·body weight, orally. Exercise consisted of running 15-60 min 5 days/week with gradually increasing intensity. AGE (P < 0.01), Exercise, and Exercise+AGE (P < 0.001) attenuated body weight gain and food efficiency ratio compared to HFD. Visceral fat and liver weight gain were attenuated (P < 0.05) with all three interventions with a greater effect on visceral fat in the Exercise+AGE than AGE (P < 0.001). In reducing visceral fat (P < 0.001), epididymal fat (P < 0.01) and liver weight (P < 0.001), Exercise+AGE was effective, but exercise showed a stronger suppressive effect than AGE. Exercise+AGE showed further additive effects on reducing visceral fat and liver weight (P < 0.001). AGE significantly attenuated the increase in total cholesterol and low-density lipoprotein-cholesterol compared with HFD (P < 0.05). Exercise+AGE attenuated the increase in triglycerides compared with HFD (P < 0.05). Exercise group significantly decrease in C-reactive protein (P < 0.001). These results suggest that AGE supplementation and exercise alone have anti-obesity, cholesterol lowering, and anti-inflammatory effects, but the combined intervention is more effective in reducing weight gain and triglycerides levels than either intervention alone. PMID:23346301
1943-01-01
The females were always strongly dominant in the samples except during May and June 1931 and May 1932 when the sexes occurred in about equal numbers. The relative abundance of the sexes did not change materially in age-groups II to V. There were no males assigned to age-groups VI and VII.
NASA Astrophysics Data System (ADS)
Marçais, J.; De Dreuzy, J. R.; Ginn, T. R.; Gueutin, P.; Leray, S.
2014-12-01
Transit time distributions (TTDs) play a key role in the transport processes, the interpretation of atmospheric tracer data and the predictions made on groundwater resources. However TTDs are not accessible from field measurements. Only hints on these TTDs can be obtained from anthropogenic tracer concentrations, also commonly called "groundwater ages". We evaluate the predictive capabilities of the information contained in anthropogenic tracer concentrations on groundwater renewal times through the use of Lumped Parameter Models (LPMs) instead of fully developed aquifer models. Towards this end, we develop an assessment methodology in three steps. First, a synthetic crystalline aquifer model representing the site of Plœmeur (Brittany, France) is used to give, at any point, references for observables quantities (anthropogenic tracer concentrations of CFC-11, 85Kr and SF6), for non-observables quantities (the TTDs), and for the prediction objective (groundwater renewal times). Second, several LPMs are considered with one, two or three parameters, and are parameterized by fitting the reference anthropogenic concentrations. Third, the reference renewal times obtained from the synthetic model are compared to the renewal times obtained independently from the LPMs. Statistical analyses over the aquifer show that a good fit of the anthropogenic tracer concentrations is a necessary but not sufficient condition for acceptable predictions. The use of only one anthropogenic tracer gives poor predictions differing by 7 to 12 years to the references. The use of two sufficiently different anthropogenic tracers not only reduce the errors but surprisingly yield to very accurate predictions with errors smaller than 3 years. The additional use of a third anthropogenic tracer does not improve the predictive capabilities. Careful a posteriori analyses reveal that reference TTDs have widely varying shapes from well peaked in recharge zones where flows are diverging to broadly
The influence of aging on susceptibility to environmental contaminants is poorly understood. The objectives of this study were to test whether oxidative stress (OS) is a potential toxicity pathway following toluene exposure and to determine if these effects are age-dependent. We ...
Reid, S A; Boyde, A
1987-02-01
We report a study to test the feasibility of studying mineral density distributions in bone using the backscattered electron signal in scanning electron microscopy. Samples were human sixth ribs ranging in age from 8 weeks to 59 years, embedded in polymethylmethacrylate (PMMA), cut, polished, and carbon coated. The proportions of pixels falling in a uniform set of gray level slices of the BSE signal were determined using a microcomputer-based image analysis system interfaced directly to the SEM. The amount of high-density bone gradually increased with age at the expense of low-density bone, and there was an associated compression of the range of the mineral density distribution. Age-related differences were noted between the density distributions in the outer and inner rib cortices. The distribution in the inner cortex in neonates was influenced by the inclusion of densely mineralized endochondral bone and cartilage trabeculae formed at the growth cartilage zone. In adults it appeared that greater bone turnover occurred in the outer cortex, perhaps reflecting a differential mechanical loading across the rib. The technique enabled rapid, unbiased discrimination between the bone of neonates, children, and adults. PMID:3455153
Robinson, L.F.; Adkins, J.F.; Scheirer, D.S.; Fernandez, D.P.; Gagnon, A.; Waller, R.G.
2007-01-01
Deep-sea corals have grown for over 200,000 yrs on the New England Seamounts in the northwest Atlantic, and this paper describes their distribution both with respect to depth and time. Many thousands of fossil scleractinian corals were collected on a series of cruises from 2003-2005; by contrast, live ones were scarce. On these seamounts, the depth distribution of fossil Desmophyllum dianthus (Esper, 1794) is markedly different to that of the colonial scleractinian corals, extending 750 m deeper in the water column to a distinct cut-off at 2500 m. This cut-off is likely to be controlled by the maximum depth of a notch-shaped feature in the seamount morphology. The ages of D. dianthus corals as determined by U-series measurements range from modern to older than 200,000 yrs. The age distribution is not constant over time, and most corals have ages from the last glacial period. Within the glacial period, increases in coral population density at Muir and Manning Seamounts coincided with times at which large-scale ocean circulation changes have been documented in the deep North Atlantic. Ocean circulation changes have an effect on coral distributions, but the cause of the link is not known. ?? 2007 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.
Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M.; Batista, Claudia Maria de Castro; Mattson, Mark P.; de Mello Coelho, Valeria
2016-01-01
We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN+ LLC. Some cortical NeuN+ neurons, GFAP+ glia limitans astrocytes, Iba-1+ microglia and S100β+ ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes. PMID:27029648
Shimabukuro, Marilia Kimie; Langhi, Larissa Gutman Paranhos; Cordeiro, Ingrid; Brito, José M; Batista, Claudia Maria de Castro; Mattson, Mark P; Mello Coelho, Valeria de
2016-01-01
We characterized cerebral Oil Red O-positive lipid-laden cells (LLC) of aging mice evaluating their distribution, morphology, density, functional activities and inflammatory phenotype. We identified LLC in meningeal, cortical and neurogenic brain regions. The density of cerebral LLC increased with age. LLC presenting small lipid droplets were visualized adjacent to blood vessels or deeper in the brain cortical and striatal parenchyma of aging mice. LLC with larger droplets were asymmetrically distributed in the cerebral ventricle walls, mainly located in the lateral wall. We also found that LLC in the subventricular region co-expressed beclin-1 or LC3, markers for autophagosome or autophagolysosome formation, and perilipin (PLIN), a lipid droplet-associated protein, suggesting lipophagic activity. Some cerebral LLC exhibited β galactosidase activity indicating a senescence phenotype. Moreover, we detected production of the pro-inflammatory cytokine TNF-α in cortical PLIN(+) LLC. Some cortical NeuN(+) neurons, GFAP(+) glia limitans astrocytes, Iba-1(+) microglia and S100β(+) ependymal cells expressed PLIN in the aging brain. Our findings suggest that cerebral LLC exhibit distinct cellular phenotypes and may participate in the age-associated neuroinflammatory processes. PMID:27029648
NASA Astrophysics Data System (ADS)
Basharat, Muhammad; Rohn, Joachim; Baig, Shahid; Ehret, Dominik
2010-05-01
The Kashmir earthquake 2005 of magnitude 7.6 in Northern Pakistan triggered thousands of mass movements. These mass movements are primarily rock fall, debris fall and rock slide. The size of mass movements varies from few cubic meters to > 85 million cubic meters rock avalanches. The relationship between the active Muzaffarabad fault and mass movements shows that the concentration of mass movement is higher in hanging wall block then the footwall block. The mostly the mass movements are shallow. However the few mass movements are deep in nature. The general mass movement direction is related to southwest Himalayan thrust direction in the northeast Himalayas of Pakistan. The patterns of mass movements are concentrated close to epicenter, Main Boundary Thrust (MBT) and along the hanging wall block of the reactivated Muzaffarabad fault. The mass movements are concentrated within 14 Km wide zone of 40 Km long Muzaffarabad fault from Muzaffarabad to Chikar fault segment and 10 Km wide zone of MBT close to the epicentre. It was observed that mass movement failure generally followed 20˚-60˚ slope. The distribution of mass movements are greater in Murree Formation as compared to other formations such as Precambrian Hazara Formation, Muzaffarabad Formation, Paleocene, Eocene rock units, Panjal Formation, Tanwal Formation and granite gneisses exposed in the earthquake affected areas. The mass movements' distribution and field investigation show that these are the result of ground shaking, structural failure, hanging wall collapse, slope failure and lithological control. These parameters played the vital role during the triggering of these mass movements.
Yuvs, G G; Ignatova, T N; Anuchin, A M; Lebedeva, V L; Shilov, V V; Khapalyuk, A V
2015-01-01
Elemental status of a person determines the qualitative and quantitative content of chemical elements in the human body. This marker allows us to estimate the level of imbalance of chemical elements and therefore health risks. The method for simultaneous quantitative and qualitative analysis of 67 elements in biomaterials has been proposed. The detailed elemental analysis of whole blood samples of 1711 healthy people (age range 0-100 years) of Moscow Region has been performed. A number of patterns of age-related changes of the element status conditionally healthy people has been estimated. Na content in the samples increased with the age of the person. Presumably, this result reflects the studied populations nutrition disorders associated with immoderate consumption of table salt. The maximum content of Ca was observed in blood samples of people age range 0-20 years (66-69 mg/kg), the Ca content in the blood samples of people age range 26-85 years was significantly lower (59-62 mg/kg). The maximum decrease of Ca was detected in blood samples of people age range of 85-100 years (57-59 mg/kg). Thisreductionin the concentration of Ca, apparently due to age-related changes of Ca balance, correlates with decrease of bone mineral density and bone mass. Iron content decreased in the blood samples of people age range 10-100 years from 480 to 390 mg/kg. Selenium content in blood of people age range 0-25 years linearly increased, remained stable high in the blood of people age range 25-55 years (0,13-0,136 mg/kg) and then gradually decreased. A graph of As content dependence from a person's age is a mirror image of the graph of Se content dependence from a person's age, which is evidence of the antagonistic effects of these elements. Graphic changes in the content of rare earth elements Eu and Ho reflect the unidirectional trend of these elements accumulation. The maximum content of these elements was observed in blood samples of people age range of 25-65 years. Perhaps a
Yuvs, G G; Ignatova, T N; Anuchin, A M; Lebedeva, V L; Shilov, V V; Khapalyuk, A V
2015-01-01
Elemental status of a person determines the qualitative and quantitative content of chemical elements in the human body. This marker allows us to estimate the level of imbalance of chemical elements and therefore health risks. The method for simultaneous quantitative and qualitative analysis of 67 elements in biomaterials has been proposed. The detailed elemental analysis of whole blood samples of 1711 healthy people (age range 0-100 years) of Moscow Region has been performed. A number of patterns of age-related changes of the element status conditionally healthy people has been estimated. Na content in the samples increased with the age of the person. Presumably, this result reflects the studied populations nutrition disorders associated with immoderate consumption of table salt. The maximum content of Ca was observed in blood samples of people age range 0-20 years (66-69 mg/kg), the Ca content in the blood samples of people age range 26-85 years was significantly lower (59-62 mg/kg). The maximum decrease of Ca was detected in blood samples of people age range of 85-100 years (57-59 mg/kg). Thisreductionin the concentration of Ca, apparently due to age-related changes of Ca balance, correlates with decrease of bone mineral density and bone mass. Iron content decreased in the blood samples of people age range 10-100 years from 480 to 390 mg/kg. Selenium content in blood of people age range 0-25 years linearly increased, remained stable high in the blood of people age range 25-55 years (0,13-0,136 mg/kg) and then gradually decreased. A graph of As content dependence from a person's age is a mirror image of the graph of Se content dependence from a person's age, which is evidence of the antagonistic effects of these elements. Graphic changes in the content of rare earth elements Eu and Ho reflect the unidirectional trend of these elements accumulation. The maximum content of these elements was observed in blood samples of people age range of 25-65 years. Perhaps a
Ermisch, J
1989-01-01
In Great Britain, using mid 1980s data and assuming no productivity increase over generations thereby making the discount rate and population growth rate 0, the average ages of household consumption and production stood at 46.3 and 41.3 respectively. Further, assuming 2% annual productivity growth and discount rates, the average consumption age was 41.7 and the average production age was 38.7. Therefore, net transfers here passed from the younger to older generations. In Japan, 1985 data shows that, under the same assumptions as Great Britain, the average ages of household consumption and production stood at 50.8 and 44.3 respectively. When assuming 2% annual productivity growth and discount rates, Japan's average consumption age was 41.7 and it's average production age was 38.7. Like Great Britain, Japan's net transfers passed from the younger to older generations. Specifically, production was significantly higher than consumption in the 20-60 year old age group and the reverse occurred in the older age groups. Even though there were similar patterns between the 2 countries, the difference between the average ages of consumption and production for Japan is much larger than for Great Britain. Further, it is even greater than the United States' whose estimates correspond to Japan's and Great Britain's. Specifically, the strength of the transfer effect is higher for Japan than Great Britain or the US because of the longer life expectancy among the Japanese. In addition, due to changes in fertility and mortality, the proportion of the 15 year olds has decreased and the proportion of those or = 65 years old has increased. Therefore net transfers have shifted in favor of the older generations.
The sex distribution of suicides by age in nations of the world.
Lester, D
1990-03-01
The ratio of the male suicide rate to the female suicide rate for each age group in 31 nations of the world was found to be associated with the wealth of the nations. The male/female suicide rate ratio was lower in wealthier nations for older adults and higher in wealthier nations for youths. The male/female suicide rate ratio was associated over the nations among the younger age groups and also among the older age groups. These results suggest that the sex ratio may be differently determined in youths and in older adults.
NASA Technical Reports Server (NTRS)
Patten, W. N.; Robertshaw, H. H.; Pierpont, D.; Wynn, R. H.
1989-01-01
A new, near-optimal feedback control technique is introduced that is shown to provide excellent vibration attenuation for those distributed parameter systems that are often encountered in the areas of aeroservoelasticity and large space systems. The technique relies on a novel solution methodology for the classical optimal control problem. Specifically, the quadratic regulator control problem for a flexible vibrating structure is first cast in a weak functional form that admits an approximate solution. The necessary conditions (first-order) are then solved via a time finite-element method. The procedure produces a low dimensional, algebraic parameterization of the optimal control problem that provides a rigorous basis for a discrete controller with a first-order like hold output. Simulation has shown that the algorithm can successfully control a wide variety of plant forms including multi-input/multi-output systems and systems exhibiting significant nonlinearities. In order to firmly establish the efficacy of the algorithm, a laboratory control experiment was implemented to provide planar (bending) vibration attenuation of a highly flexible beam (with a first clamped-free mode of approximately 0.5 Hz).
NASA Astrophysics Data System (ADS)
Methekar, R. N.; Prasad, V.; Gudi, R. D.
To satisfy high power density demand in proton exchange membrane fuel cells (PEMFCs), a robust control strategy is essential. A linear ratio control strategy is examined in this work. The manipulated variables are selected using steady-state relative gain array (RGA) analysis to be the inlet molar flow rates of hydrogen and coolant, and the controlled variables are average power density and average solid temperature, respectively. By selecting proper manipulated variables, the PEMFC does not exhibit sign change in gain and hence can be controlled by using a linear controller. Transfer function models obtained from step tests on the distributed parameter PEMFC model are used to design controllers for the multiple input-multiple output (MIMO) system. In addition, a ratio control strategy is proposed and evaluated, where the inlet molar flow rate of oxygen is used as a