Mathematical treatment of isotopologue and isotopomer speciation and fractionation in biochemical kinetics

Science.gov (United States)

Maggi, Federico; Riley, William J.

2010-03-01

We present a mathematical treatment of the kinetic equations that describe isotopologue and isotopomer speciation and fractionation during enzyme-catalyzed biochemical reactions. These equations, presented here with the name GEBIK (general equations for biochemical isotope kinetics) and GEBIF (general equations for biochemical isotope fractionation), take into account microbial biomass and enzyme dynamics, reaction stoichiometry, isotope substitution number, and isotope location within each isotopologue and isotopomer. In addition to solving the complete GEBIK and GEBIF, we also present and discuss two approximations to the full solutions under the assumption of biomass-free and enzyme steady-state, and under the quasi-steady-state assumption as applied to the complexation rate. The complete and approximate approaches are applied to observations of biological denitrification in soils. Our analysis highlights that the full GEBIK and GEBIF provide a more accurate description of concentrations and isotopic compositions of substrates and products throughout the reaction than do the approximate forms. We demonstrate that the isotopic effects of a biochemical reaction depend, in the most general case, on substrate and complex concentrations and, therefore, the fractionation factor is a function of time. We also demonstrate that inverse isotopic effects can occur for values of the fractionation factor smaller than 1, and that reactions that do not discriminate isotopes do not necessarily imply a fractionation factor equal to 1.

In vivo dynamic turnover of cerebral 13C isotopomers from [U- 13C]glucose

Science.gov (United States)

Xu, Su; Shen, Jun

2006-10-01

An INEPT-based 13C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic 13C isotopomer turnover from intravenously infused [U- 13C]glucose in a 211 μL voxel located in the adult rat brain. The INEPT-based 1H → 13C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B 1 inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with 1JC4C5 = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with 1JC3C4 = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.

Isotopomer analysis of lipid biosynthesis by high resolution mass spectrometry and NMR

Energy Technology Data Exchange (ETDEWEB)

Lane, Andrew N., E-mail: anlane01@louisville.edu [JG Brown Cancer Center, 529 S. Jackson Street, Louisville, KY 40202 (United States); Center for Regulatory and Environmental Analytical Metabolomics (CREAM), University of Louisville, Louisville, KY (United States); Fan, Teresa W.-M. [JG Brown Cancer Center, 529 S. Jackson Street, Louisville, KY 40202 (United States); Center for Regulatory and Environmental Analytical Metabolomics (CREAM), University of Louisville, Louisville, KY (United States); Department of Chemistry, University of Louisville, Louisville, KY 40292 (United States); Xie, Zhengzhi; Moseley, Hunter N.B.; Higashi, Richard M. [Center for Regulatory and Environmental Analytical Metabolomics (CREAM), University of Louisville, Louisville, KY (United States); Department of Chemistry, University of Louisville, Louisville, KY 40292 (United States)

2009-10-05

We have coupled 2D-NMR and infusion FT-ICR-MS with computer-assisted assignment to profile {sup 13}C-isotopologues of glycerophospholipids (GPL) directly in crude cell extracts, resulting in very high information throughput of >3000 isobaric molecules in a few minutes. A mass accuracy of better than 1 ppm combined with a resolution of 100,000 at the measured m/z was required to distinguish isotopomers from other GPL structures. Isotopologue analysis of GPLs extracted from LCC2 breast cancer cells grown on [U-{sup 13}C]-glucose provided a rich trove of information about the biosynthesis and turnover of the GPLs. The isotopologue intensity ratios from the FT-ICR-MS were accurate to {approx}1% or better based on natural abundance background, and depended on the signal-to-nose ratio. The time course of incorporation of {sup 13}C from [U-{sup 13}C]-glucose into a particular phosphatidylcholine was analyzed in detail, to provide a quantitative measure of the sizes of glycerol, acetyl CoA and total GPL pools in growing LCC2 cells. Independent and complementary analysis of the positional {sup 13}C enrichment in the glycerol and fatty acyl chains obtained from high resolution 2D NMR was used to verify key aspects of the model. This technology enables simple and rapid sample preparation, has rapid analysis, and is generally applicable to unfractionated GPLs of almost any head group, and to mixtures of other classes of metabolites.

Isotopomer analysis of lipid biosynthesis by high resolution mass spectrometry and NMR

International Nuclear Information System (INIS)

Lane, Andrew N.; Fan, Teresa W.-M.; Xie, Zhengzhi; Moseley, Hunter N.B.; Higashi, Richard M.

2009-01-01

We have coupled 2D-NMR and infusion FT-ICR-MS with computer-assisted assignment to profile 13 C-isotopologues of glycerophospholipids (GPL) directly in crude cell extracts, resulting in very high information throughput of >3000 isobaric molecules in a few minutes. A mass accuracy of better than 1 ppm combined with a resolution of 100,000 at the measured m/z was required to distinguish isotopomers from other GPL structures. Isotopologue analysis of GPLs extracted from LCC2 breast cancer cells grown on [U- 13 C]-glucose provided a rich trove of information about the biosynthesis and turnover of the GPLs. The isotopologue intensity ratios from the FT-ICR-MS were accurate to ∼1% or better based on natural abundance background, and depended on the signal-to-nose ratio. The time course of incorporation of 13 C from [U- 13 C]-glucose into a particular phosphatidylcholine was analyzed in detail, to provide a quantitative measure of the sizes of glycerol, acetyl CoA and total GPL pools in growing LCC2 cells. Independent and complementary analysis of the positional 13 C enrichment in the glycerol and fatty acyl chains obtained from high resolution 2D NMR was used to verify key aspects of the model. This technology enables simple and rapid sample preparation, has rapid analysis, and is generally applicable to unfractionated GPLs of almost any head group, and to mixtures of other classes of metabolites.

Are Parton Distributions Positive?

CERN Document Server

Forte, Stefano; Ridolfi, Giovanni; Altarelli, Guido; Forte, Stefano; Ridolfi, Giovanni

1999-01-01

We show that the naive positivity conditions on polarized parton distributions which follow from their probabilistic interpretation in the naive parton model are reproduced in perturbative QCD at the leading log level if the quark and gluon distribution are defined in terms of physical processes. We show how these conditions are modified at the next-to-leading level, and discuss their phenomenological implications, in particular in view of the determination of the polarized gluon distribution

Are parton distributions positive?

International Nuclear Information System (INIS)

Forte, Stefano; Altarelli, Guido; Ridolfi, Giovanni

1999-01-01

We show that the naive positivity conditions on polarized parton distributions which follow from their probabilistic interpretation in the naive parton model are reproduced in perturbative QCD at the leading log level if the quark and gluon distribution are defined in terms of physical processes. We show how these conditions are modified at the next-to-leading level, and discuss their phenomenological implications, in particular in view of the determination of the polarized gluon distribution

Grasland Stable Isotope Flux Measurements: Three Isotopomers of Carbon Dioxide Measured by QCL Spectroscopy

Science.gov (United States)

Zeeman, M. J.; Tuzson, B.; Eugster, W.; Werner, R. A.; Buchmann, N.; Emmenegger, L.

2007-12-01

To improve our understanding of greenhouse gas dynamics of managed ecosystems such as grasslands, we not only need to investigate the effects of management (e.g., grass cuts) and weather events (e.g., rainy days) on carbon dioxide fluxes, but also need to increase the time resolution of our measurements. Thus, for the first time, we assessed respiration and assimilation fluxes with high time resolution (5Hz) stable isotope measurements at an intensively managed farmland in Switzerland (Chamau, 400m ASL). Two different methods were used to quantify fluxes of carbon dioxide and associated fluxes of stable carbon isotopes: (1) the flux gradient method, and (2) the eddy covariance method. During a week long intensive measurement campaign, we (1) measured mixing ratios of carbon dioxide isotopomers (12C16O2, 12C16O18O, 13C16O2) with a Quantum Cascade Laser (QCL, Aerodyne Inc.) spectroscope and (2) collected air samples for isotope analyses (13C/12C) and (18O/16O) of carbon dioxide by Isotope Ratio Mass Spectrometry (IRMS, Finnigan) every two hours, concurrently along a height profile (z = 0.05; 0.10; 0.31; 2.15m). In the following week, the QCL setup was used for closed-path eddy covariance flux measurement of the carbon dioxide isotopomers, with the air inlet located next to an open-path Infra Red Gas Analyzers (IRGA, LiCor 7500) used simultaneously for carbon dioxide measurements. During this second week, an area of grass inside the footprint was cut and harvested after several days. The first results of in-field continuous QCL measurements of carbon dioxide mixing ratios and their stable isotopic ratios show good agreement with IRGA measurements and isotope analysis of flask samples by IRMS. Thus, QCL spectroscopy is a very promising tool for stable isotope flux investigations.

Isotopomer analysis of production and consumption mechanisms of N2O and CH4 in an advanced wastewater treatment system.

Science.gov (United States)

Toyoda, Sakae; Suzuki, Yuuri; Hattori, Shohei; Yamada, Keita; Fujii, Ayako; Yoshida, Naohiro; Kouno, Rina; Murayama, Kouki; Shiomi, Hiroshi

2011-02-01

Wastewater treatment processes are believed to be anthropogenic sources of nitrous oxide (N(2)O) and methane (CH(4)). However, few studies have examined the mechanisms and controlling factors in production of these greenhouse gases in complex bacterial systems. To elucidate production and consumption mechanisms of N(2)O and CH(4) in microbial consortia during wastewater treatment and to characterize human waste sources, we measured their concentrations and isotopomer ratios (elemental isotope ratios and site-specific N isotope ratios in asymmetric molecules of NNO) in water and gas samples collected by an advanced treatment system in Tokyo. Although the estimated emissions of N(2)O and CH(4) from the system were found to be lower than those from the typical treatment systems reported before, water in biological reaction tanks was supersaturated with both gases. The concentration of N(2)O, produced mainly by nitrifier-denitrification as indicated by isotopomer ratios, was highest in the oxic tank (ca. 4000% saturation). The dissolved CH(4) concentration was highest in in-flow water (ca. 3000% saturation). It decreased gradually during treatment. Its carbon isotope ratio indicated that the decrease resulted from bacterial CH(4) oxidation and that microbial CH(4) production can occur in anaerobic and settling tanks.

Liquid State Thermochemical Decomposition of Neat 1,3,5,5-Tetranitrohexahydropyrimidine (DNNC) and its DNNC-d2, DNNC-d4, DNNC-d6 Structural Isotopomers: Mechanistic Entrance into the DNNC Molecule

National Research Council Canada - National Science Library

Shackelford, S. A; Menapace, J. A; Goldman, J. F

2007-01-01

... thermochemical decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d2, DNNC-d4, and DNNC-d6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule...

Liquid State Thermochemical Decomposition of Neat 1,3,5,5-Tetranitrohexahydropyrimidine (DNNC) and its DNNC-d2, DNNC-d4, DNNC-d6 Structural Isotopomers: Mechanistic Entrance into the DNNC Molecule (Preprint)

National Research Council Canada - National Science Library

Shackelford, S. A; Menapace, J. A; Goldman, J. F

2007-01-01

... decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d2, DNNC-d4, and DNNC-d6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule...

Threshold Photoelectron Spectroscopy of the Methyl Radical Isotopomers, CH3, CH2D, CHD2 and CD3: Synergy between VUV Synchrotron Radiation Experiments and Explicitly Correlated Coupled Cluster Calculations

Czech Academy of Sciences Publication Activity Database

Cunha de Miranda, B. K.; Alcaraz, Ch.; Elhanine, M.; Noller, B.; Hemberger, P.; Fischer, I.; Garcia, G. A.; Soldi-Lose, H.; Gans, B.; Mendes, L. A. V.; Boyé-Péronne, S.; Douin, S.; Žabka, Ján; Botschwina, P.

2010-01-01

Roč. 114, č. 14 (2010), s. 4818-4830 ISSN 1089-5639 Grant - others:CNRS-AVCR(FR) 20201 Institutional research plan: CEZ:AV0Z40400503 Keywords : Threshold photoelectron spectroscopy * isotopomers * clusters Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.732, year: 2010

Metabolic Effects of Hypoxia in Colorectal Cancer by 13C NMR Isotopomer Analysis

Directory of Open Access Journals (Sweden)

Ana M. Abrantes

2014-01-01

Full Text Available 13C NMR isotopomer analysis was used to characterize intermediary metabolism in three colorectal cancer cell lines (WiDr, LS1034, and C2BBe1 and determine the “metabolic remodeling” that occurs under hypoxia. Under normoxia, the three colorectal cancer cell lines present high rates of lactate production and can be seen as “Warburg” like cancer cells independently of substrate availability, since such profile was dominant at both high and low glucose media contents. The LS1034 was the less glycolytic of the three cell lines and was the most affected by the event of hypoxia, raising abruptly glucose consumption and lactate production. The other two colorectal cell lines, WiDr and C2BBe1, adapted better to hypoxia and were able to maintain their oxidative fluxes even at the very low levels of oxygen. These differential metabolic behaviors of the three colorectal cell lines show how important an adequate knowledge of the “metabolic remodeling” that follows a given cancer treatment is towards the correct (redesign of therapeutic strategies against cancer.

Study of Stationary Phase Metabolism Via Isotopomer Analysis of Amino Acids from an Isolated Protein

Energy Technology Data Exchange (ETDEWEB)

Shaikh, AfshanS.; Tang, YinjieJ.; Mukhopadhyay, Aindrila; Martin, Hector Garcia; Gin, Jennifer; Benke, Peter; Keasling, Jay D.

2009-09-14

Microbial production of many commercially important secondary metabolites occurs during stationary phase, and methods to measure metabolic flux during this growth phase would be valuable. Metabolic flux analysis is often based on isotopomer information from proteinogenic amino acids. As such, flux analysis primarily reflects the metabolism pertinent to the growth phase during which most proteins are synthesized. To investigate central metabolism and amino acids synthesis activity during stationary phase, addition of fully 13C-labeled glucose followed by induction of green fluorescent protein (GFP) expression during stationary phase was used. Our results indicate that Escherichia coli was able to produce new proteins (i.e., GFP) in the stationary phase, and the amino acids in GFP were mostly from degraded proteins synthesized during the exponential growth phase. Among amino acid biosynthetic pathways, only those for serine, alanine, glutamate/glutamine, and aspartate/asparagine had significant activity during the stationary phase.

Positivity properties of phase-plane distribution functions

NARCIS (Netherlands)

Janssen, A.J.E.M.

1984-01-01

The aim of this paper is to compare the members of Cohen's class of phase-plane distributions with respect to positivity properties. It is known that certain averages (which are in a sense compatible with Heisenberg's uncertainty principle) of the Wigner distribution over the phase-plane yield

On the maximum entropy distributions of inherently positive nuclear data

Energy Technology Data Exchange (ETDEWEB)

Taavitsainen, A., E-mail: aapo.taavitsainen@gmail.com; Vanhanen, R.

2017-05-11

The multivariate log-normal distribution is used by many authors and statistical uncertainty propagation programs for inherently positive quantities. Sometimes it is claimed that the log-normal distribution results from the maximum entropy principle, if only means, covariances and inherent positiveness of quantities are known or assumed to be known. In this article we show that this is not true. Assuming a constant prior distribution, the maximum entropy distribution is in fact a truncated multivariate normal distribution – whenever it exists. However, its practical application to multidimensional cases is hindered by lack of a method to compute its location and scale parameters from means and covariances. Therefore, regardless of its theoretical disadvantage, use of other distributions seems to be a practical necessity. - Highlights: • Statistical uncertainty propagation requires a sampling distribution. • The objective distribution of inherently positive quantities is determined. • The objectivity is based on the maximum entropy principle. • The maximum entropy distribution is the truncated normal distribution. • Applicability of log-normal or normal distribution approximation is limited.

An Autonomous Distributed Fault-Tolerant Local Positioning System

Science.gov (United States)

Malekpour, Mahyar R.

2017-01-01

We describe a fault-tolerant, GPS-independent (Global Positioning System) distributed autonomous positioning system for static/mobile objects and present solutions for providing highly-accurate geo-location data for the static/mobile objects in dynamic environments. The reliability and accuracy of a positioning system fundamentally depends on two factors; its timeliness in broadcasting signals and the knowledge of its geometry, i.e., locations and distances of the beacons. Existing distributed positioning systems either synchronize to a common external source like GPS or establish their own time synchrony using a scheme similar to a master-slave by designating a particular beacon as the master and other beacons synchronize to it, resulting in a single point of failure. Another drawback of existing positioning systems is their lack of addressing various fault manifestations, in particular, communication link failures, which, as in wireless networks, are increasingly dominating the process failures and are typically transient and mobile, in the sense that they typically affect different messages to/from different processes over time.

Positional effects on distribution of ventilation in chronic obstructive pulmonary disease

International Nuclear Information System (INIS)

Shim, C.; Chun, K.J.; Williams, M.H. Jr.; Blaufox, M.D.

1986-01-01

Ventilation is distributed predominantly to the dependent lung in normal persons in the decubitus position. We evaluated the distribution of ventilation in four patients with mild-to-moderate chronic obstructive pulmonary disease using 81mKr gas. Patients were tested in the sitting and right and left decubitus positions with and without the application of positive end expiratory pressure (PEEP). In contrast to findings in controls, ventilation was predominantly distributed to the nondependent lung in patients in the decubitus position. Mean ventilation in the right lung decreased from 51% of the total in the sitting position to 31% in the right decubitus position; it increased with the application of 10 cm PEEP. Reduced ventilation in the dependent lung most likely is caused by closure of the airways after a decrease in volume. Application of PEEP resulted in increased lung volume and preferential distribution of ventilation to the dependent lung

Point processes and the position distribution of infinite boson systems

International Nuclear Information System (INIS)

Fichtner, K.H.; Freudenberg, W.

1987-01-01

It is shown that to each locally normal state of a boson system one can associate a point process that can be interpreted as the position distribution of the state. The point process contains all information one can get by position measurements and is determined by the latter. On the other hand, to each so-called Σ/sup c/-point process Q they relate a locally normal state with position distribution Q

MATLAB implementation of satellite positioning error overbounding by generalized Pareto distribution

Science.gov (United States)

Ahmad, Khairol Amali; Ahmad, Shahril; Hashim, Fakroul Ridzuan

2018-02-01

In the satellite navigation community, error overbound has been implemented in the process of integrity monitoring. In this work, MATLAB programming is used to implement the overbounding of satellite positioning error CDF. Using a trajectory of reference, the horizontal position errors (HPE) are computed and its non-parametric distribution function is given by the empirical Cumulative Distribution Function (ECDF). According to the results, these errors have a heavy-tailed distribution. Sınce the ECDF of the HPE in urban environment is not Gaussian distributed, the ECDF is overbound with the CDF of the generalized Pareto distribution (GPD).

Infrared and Raman Spectra of and Isotopomers: A DFT-PT2 Anharmonic Study

Directory of Open Access Journals (Sweden)

Andrea Alparone

2013-01-01

Full Text Available IR and Raman spectra of selenophene and of its perdeuterated isotopomer have been obtained in gas phase through density-functional theory (DFT computations. Vibrational wavenumbers have been calculated using harmonic and anharmonic second-order perturbation theory (PT2 procedures with the B3LYP method and the 6-311 basis set. Anharmonic overtones have been determined by means of the PT2 method. The introduction of anharmonic terms decreases the harmonic wavenumbers, giving a significantly better agreement with the experimental data. The most significant anharmonic effects occur for the C–H and C–D stretching modes, the observed H/D isotopic wavenumber redshifts being satisfactorily reproduced by the PT2 computations within 6–20 cm−1 (1–3%. In the spectral region between 500 cm−1 and 1500 cm−1, the IR spectra are dominated by the out-of-plane C–H (C–D bending transition, whereas the Raman spectra are mainly characterized by a strong peak mainly attributed to the C=C + C–C bonds stretching vibration with the contribution of the in-plane C–H (C–D bending deformation. The current results confirm that the PT2 approach combined with the B3LYP/6-311 level of calculation is a satisfactory choice for predicting vibrational spectra of cyclic molecules.

Vacuum ultraviolet photochemistry of CH4 and isotopomers. II. Product channel fields and absorption spectra

International Nuclear Information System (INIS)

Wang, Jen-Han; Liu, Kopin; Min, Zhiyuan; Su, Hongmei; Bersohn, Richard; Preses, Jack; Larese, John Z.

2000-01-01

In part I of this work the relative velocities and anisotropies of the atomic H and D fragments from methane photolysis at 10.2 eV were measured. In this paper the relative abundance of the methyl and methylene fragments are reported. A complete set of quantum yields for the different photodissociation channels of each isotopomer is obtained by combining the two sets of data. Previously it was found that H atoms are almost four times more likely than D atoms to be ejected; now it is found that hydrogen molecule photofragments are much richer in H atoms than in D. Overall, the heavier D atoms are more likely than the H atoms to remain attached to the carbon atom. An implication for astrophysics is discussed. The VUV absorption spectra of CH 4 and CH 3 D are almost identical both at room temperature and 75 K. There is, as expected, no variation in the absorption spectrum with temperature. Evidence is given that all or almost all of the methylene is produced in the a 1 A 1 and not in the ground 3 B 1 state. (c) 2000 American Institute of Physics

Insight into nitrous oxide production processes in the western North Pacific based on a marine ecosystem isotopomer model

Science.gov (United States)

Yoshikawa, C.; Sasai, Y.; Wakita, M.; Honda, M. C.; Fujiki, T.; Harada, N.; Makabe, A.; Matsushima, S.; Toyoda, S.; Yoshida, N.; Ogawa, N. O.; Suga, H.; Ohkouchi, N.

2016-02-01

Based on the observed inverse relationship between the dissolved oxygen and N2O concentrations in the ocean, previous models have indirectly predicted marine N2O emissions from the apparent oxygen utilization (AOU), In this study, a marine ecosystem model that incorporates nitrous oxide (N2O) production processes (i.e., ammonium oxidation during nitrification and nitrite reduction during nitrifier denitrification) was newly developed to estimate the sea-air N2O flux and to quantify N2O production processes. Site preference of 15N (SP) in N2O isotopomers (14N15N16O and 15N14N16O) and the average nitrogen isotope ratio (δ15N) were added to the model because they are useful tracers to distinguish between ammonium oxidation and nitrite reduction. This model was applied to two contrasting time series sites, a subarctic station (K2) and a subtropical station (S1) in the western North Pacific. The model was validated with observed nitrogen concentration and nitrogen isotopomer datasets, and successfully simulated the higher N2O concentrations, higher δ15N values, and higher site preference values for N2O at K2 compared with S1. The annual mean N2O emissions were estimated to be 34 mg N m-2 yr-1 at K2 and 2 mg N m-2 yr-1 at S1. Using this model, we conducted three case studies: 1) estimating the ratio of in-situ biological N2O production to nitrate (NO3-) production during nitrification, 2) estimating the ratio of N2O production by ammonium oxidation to that by nitrite reduction, and 3) estimating the ratio of AOA ammonium oxidation to AOB ammonium oxidation. The results of case studies estimated the ratios of in situ biological N2O production to nitrate production during nitrification to be 0.22% at K2 and 0.06% at S1. It is also suggested that N2O was mainly produced via ammonium oxidation at K2 but was produced via both ammonium oxidation and nitrite reduction at S1. It is also revealed that 80% of the ammonium oxidation at K2 was caused by archaea in the subsurface

Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract.

Science.gov (United States)

Sano, Yuto; Matsuda, Kazuya; Okamoto, Minoru; Takehana, Kazushige; Hirayama, Kazuko; Taniyama, Hiroyuki

2016-02-01

Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC class II (MHC II) and CD20. To demonstrate the site of their greatest distribution, positive cells were manually counted in 3 different parts of the uveal tract (ciliary body, iris and choroid), and their average number was assessed by statistical analysis. The distribution of pleomorphic CD163- and MHC II-expressed cells was detected throughout the equine uveal tract, but no CD20-expressed cells were detected. The statistical analysis demonstrated the distribution of CD163- and MHC II-positive cells focusing on the ciliary body. These results demonstrated that the ciliary body is the largest site of their distribution in the normal equine uveal tract, and the ciliary body is considered to play important roles in uveal and/or ocular immune homeostasis. The data provided in this study will help further understanding of equine ocular immunity in the normal state and might be beneficial for understanding of mechanisms of ocular disorders, such as equine uveitis.

Spatial distribution of potential and positive Aedes aegypti breeding sites

Directory of Open Access Journals (Sweden)

Daniel Elías Cuartas

2017-03-01

Conclusions: The spatial relationship between positive and potential A. aegypti breeding sites both indoors and outdoors is dynamic and highly sensitive to the characteristics of each territory. Knowing how positive and potential breeding sites are distributed contributes to the prioritization of resources and actions in vector control programs.

NMR-based stable isotope resolved metabolomics in systems biochemistry

International Nuclear Information System (INIS)

Fan, Teresa W-M.; Lane, Andrew N.

2011-01-01

An important goal of metabolomics is to characterize the changes in metabolic networks in cells or various tissues of an organism in response to external perturbations or pathologies. The profiling of metabolites and their steady state concentrations does not directly provide information regarding the architecture and fluxes through metabolic networks. This requires tracer approaches. NMR is especially powerful as it can be used not only to identify and quantify metabolites in an unfractionated mixture such as biofluids or crude cell/tissue extracts, but also determine the positional isotopomer distributions of metabolites derived from a precursor enriched in stable isotopes such as 13 C and 15 N via metabolic transformations. In this article we demonstrate the application of a variety of 2-D NMR editing experiments to define the positional isotopomers of compounds present in polar and non-polar extracts of human lung cancer cells grown in either [U– 13 C]-glucose or [U– 13 C, 15 N]-glutamine as source tracers. The information provided by such experiments enabled unambiguous reconstruction of metabolic pathways, which is the foundation for further metabolic flux modeling.

Modeling the probability distribution of positional errors incurred by residential address geocoding

Directory of Open Access Journals (Sweden)

Mazumdar Soumya

2007-01-01

Full Text Available Abstract Background The assignment of a point-level geocode to subjects' residences is an important data assimilation component of many geographic public health studies. Often, these assignments are made by a method known as automated geocoding, which attempts to match each subject's address to an address-ranged street segment georeferenced within a streetline database and then interpolate the position of the address along that segment. Unfortunately, this process results in positional errors. Our study sought to model the probability distribution of positional errors associated with automated geocoding and E911 geocoding. Results Positional errors were determined for 1423 rural addresses in Carroll County, Iowa as the vector difference between each 100%-matched automated geocode and its true location as determined by orthophoto and parcel information. Errors were also determined for 1449 60%-matched geocodes and 2354 E911 geocodes. Huge (> 15 km outliers occurred among the 60%-matched geocoding errors; outliers occurred for the other two types of geocoding errors also but were much smaller. E911 geocoding was more accurate (median error length = 44 m than 100%-matched automated geocoding (median error length = 168 m. The empirical distributions of positional errors associated with 100%-matched automated geocoding and E911 geocoding exhibited a distinctive Greek-cross shape and had many other interesting features that were not capable of being fitted adequately by a single bivariate normal or t distribution. However, mixtures of t distributions with two or three components fit the errors very well. Conclusion Mixtures of bivariate t distributions with few components appear to be flexible enough to fit many positional error datasets associated with geocoding, yet parsimonious enough to be feasible for nascent applications of measurement-error methodology to spatial epidemiology.

The rank of a normally distributed matrix and positive definiteness of a noncentral Wishart distributed matrix

NARCIS (Netherlands)

Steerneman, A. G. M.; van Perlo-ten Kleij, Frederieke

2008-01-01

If X similar to N-nxk(M, I-n circle times Sigma), then S = X'X has the noncentral Wishart distribution W-k(')(n, Sigma; A), where Lambda = M'M. Here Sigma is allowed to be singular. It is well known that if Lambda = 0, then S has a (central) Wishart distribution and. S is positive definite with

Position Reconstruction and Charge Distribution in LHCb VELO Silicon Sensors

CERN Document Server

Versloot, TW; Akiba, K; Artuso, M; Van Beuzekom, M; Borel, J; Bowcock, TJV; Buytaert, J; Collins, P; Dumps, R; Dwyer, L; Eckstein, D; Eklund, L; Ferro-Luzzi, M; Frei, R; Gersabek M; Haefeli, G; Hennessy, K; Huse, T; Jans, E; John, M; Ketel, TJ; Keune, A; Lastoviicka, T; Mountain, R; Neufeld, N; Parkes, C; Stone, S; Szumlak, T; Tobin, M; Van Lysebetten, A; Viret, S; De Vries, H; Wang, J

2007-01-01

In 2006, a partially equipped LHCb VELO detector half was characterised in a test beam experiment (Alignment Challenge and Detector Commissioning, ACDC3). The position reconstruction and resolution for 2-strip R-sensor clusters was studied as a function of strip pitch and track inclination on the sensor surface. The Charge Density Distribution (CDD) is derived from the weighted charge distribution. It becomes asymmetric for tracks non-perpendicular to the strip surface. It is shown that the asymmetric broadening of the CDD around the track intercept position results in a linear eta-function at higher angles (>6 degrees). The sensor spatial resolution is determined both using a linear weighted mean of strip charges, as well as a third-order polynomial approximation via a eta-correction. The experimental results are in agreement with previous simulations. Future studies are underway to determine the angle and pitch dependent parameters which will be implemented in the LHCb VELO cluster position software tools.

A Positive and a Normative Theory of Income Distribution

NARCIS (Netherlands)

J. Tinbergen (Jan)

1970-01-01

textabstractA positive theory of income distribution based on assumptions concerning the supply of and demand for each type of productive service is presented. The demand function of the organizers of production may be derived from the maximization of profits with the income scale and the production

Stereoselective quantification of methadone and a d(6)-labeled isotopomer using high performance liquid chromatography-atmospheric pressure chemical ionization mass-spectrometry: application to a pharmacokinetic study in a methadone maintained subject.

Science.gov (United States)

Foster, David J R; Morton, Erin B; Heinkele, Georg; Mürdter, Thomas E; Somogyi, Andrew A

2006-08-01

There is evidence that the apparent oral clearance of rac-methadone is induced during the early phase of methadone maintenance treatment. However, it is not known if this is due to changes in bioavailability or if this phenomenon is stereoselective. This knowledge can be obtained by administering a dose of stable-labeled methadone at selected times during ongoing treatment. Therefore, the authors developed a stereoselective high performance liquid chromatography-atmospheric pressure chemical ionization mass-spectrometry assay for the quantification of the enantiomers of methadone and a d(6)-labeled isotopomer. The compounds were quantified in a single assay after liquid-liquid extraction and stereoselective high performance liquid chromatograph with atmospheric pressure chemical ionization-mass spectrometry detection. The following ions were monitored: m/z 310.15 for unlabeled methadone; m/z 316.15 for methadone-d(6); and m/z 313.15 for the methadone-d(3) (internal standard). Calibration curves ranged from 0.5 to 75 ng/mL for each compound. Extraction recovery was approximately 80% for all analytes, without evidence of differences between the unlabeled and stable-labeled compounds or concentration dependency. Minor ion promotion was observed (d(3)-labeled internal standard, with peak area ratios in extracted samples identical to control injections. The isotopomers did not alter each others' ionisation, even at 10:1 concentration ratios, and 10-fold diluted samples were within 10% of the nominal concentration. Assay performance was acceptable, with interassay and intra-assay bias and precision d(6) in a patient receiving chronic oral methadone maintenance therapy.

Patient positioning and its influence on dose distribution

International Nuclear Information System (INIS)

Morrissey, J.; Moss, R.; Watkins, P.

2000-01-01

In comparison to conventional radiotherapy, the positioning of a patient for BNCT treatment has some unique aspects. In particular, the neutron beam coming from the core of a nuclear research reactor is fixed and horizontal. In particular, a head fixation mask, which is prepared at the patient referral hospital, is included in the CT images. The mask allows reproducible positioning for use during the treatment. Fiducial markers placed on the mask before imaging, provide reference points. The INEEL treatment planning code used in Petten produces a beam angle, and beam line entrance and exit co-ordinates. These are related to the fiducial marker co-ordinates. A spreadsheet, named COSINE, developed at Petten produces positioning co-ordinates from the data produced by the rtt MC code. These co-ordinates are related to a positioning frame, which allows the marking of the beams on the mask. In order to have reliable treatment data, the influence of small deviations of angle or target point on dose distribution must be known. To demonstrate this, a number of beams have been calculated with the Petten beam, with slight variations and compared with an approved plan. (author)

Measurement of spatial dose-rate distribution using a position sensitive detector

International Nuclear Information System (INIS)

Emoto, T.; Torii, T.; Nozaki, T.; Ando, H.

1994-01-01

Recently, the radiation detectors using plastic scintillation fibers (PSF) have been developed to measure the positions exposed to radiation such as neutrons and high energy charged particles. In particular, the time of flight (TOF) method for measuring the difference of time that two directional signals of scintillation light reach both ends of a PSF is a rather simple method for the measurement of the spatial distribution of fast neutron fluence rate. It is possible to use the PSF in nuclear facility working areas because of its flexibility, small diameter and long length. In order to apply TOF method to measure spatial gamma dose rate distribution, the characteristic tests of a detector using PSFs were carried out. First, the resolution of irradiated positions and the counting efficiency were measured with collimated gamma ray. The sensitivity to unit dose rate was also obtained. The measurement of spatial dose rate distribution was also carried out. The sensor is made of ten bundled PSFs, and the experimental setup is described. The experiment and the results are reported. It was found that the PSF detector has the good performance to measure spatial gamma dose rate distribution. (K.I.)

ALLocator: an interactive web platform for the analysis of metabolomic LC-ESI-MS datasets, enabling semi-automated, user-revised compound annotation and mass isotopomer ratio analysis.

Science.gov (United States)

Kessler, Nikolas; Walter, Frederik; Persicke, Marcus; Albaum, Stefan P; Kalinowski, Jörn; Goesmann, Alexander; Niehaus, Karsten; Nattkemper, Tim W

2014-01-01

Adduct formation, fragmentation events and matrix effects impose special challenges to the identification and quantitation of metabolites in LC-ESI-MS datasets. An important step in compound identification is the deconvolution of mass signals. During this processing step, peaks representing adducts, fragments, and isotopologues of the same analyte are allocated to a distinct group, in order to separate peaks from coeluting compounds. From these peak groups, neutral masses and pseudo spectra are derived and used for metabolite identification via mass decomposition and database matching. Quantitation of metabolites is hampered by matrix effects and nonlinear responses in LC-ESI-MS measurements. A common approach to correct for these effects is the addition of a U-13C-labeled internal standard and the calculation of mass isotopomer ratios for each metabolite. Here we present a new web-platform for the analysis of LC-ESI-MS experiments. ALLocator covers the workflow from raw data processing to metabolite identification and mass isotopomer ratio analysis. The integrated processing pipeline for spectra deconvolution "ALLocatorSD" generates pseudo spectra and automatically identifies peaks emerging from the U-13C-labeled internal standard. Information from the latter improves mass decomposition and annotation of neutral losses. ALLocator provides an interactive and dynamic interface to explore and enhance the results in depth. Pseudo spectra of identified metabolites can be stored in user- and method-specific reference lists that can be applied on succeeding datasets. The potential of the software is exemplified in an experiment, in which abundance fold-changes of metabolites of the l-arginine biosynthesis in C. glutamicum type strain ATCC 13032 and l-arginine producing strain ATCC 21831 are compared. Furthermore, the capability for detection and annotation of uncommon large neutral losses is shown by the identification of (γ-)glutamyl dipeptides in the same strains

ALLocator: an interactive web platform for the analysis of metabolomic LC-ESI-MS datasets, enabling semi-automated, user-revised compound annotation and mass isotopomer ratio analysis.

Directory of Open Access Journals (Sweden)

Nikolas Kessler

Full Text Available Adduct formation, fragmentation events and matrix effects impose special challenges to the identification and quantitation of metabolites in LC-ESI-MS datasets. An important step in compound identification is the deconvolution of mass signals. During this processing step, peaks representing adducts, fragments, and isotopologues of the same analyte are allocated to a distinct group, in order to separate peaks from coeluting compounds. From these peak groups, neutral masses and pseudo spectra are derived and used for metabolite identification via mass decomposition and database matching. Quantitation of metabolites is hampered by matrix effects and nonlinear responses in LC-ESI-MS measurements. A common approach to correct for these effects is the addition of a U-13C-labeled internal standard and the calculation of mass isotopomer ratios for each metabolite. Here we present a new web-platform for the analysis of LC-ESI-MS experiments. ALLocator covers the workflow from raw data processing to metabolite identification and mass isotopomer ratio analysis. The integrated processing pipeline for spectra deconvolution "ALLocatorSD" generates pseudo spectra and automatically identifies peaks emerging from the U-13C-labeled internal standard. Information from the latter improves mass decomposition and annotation of neutral losses. ALLocator provides an interactive and dynamic interface to explore and enhance the results in depth. Pseudo spectra of identified metabolites can be stored in user- and method-specific reference lists that can be applied on succeeding datasets. The potential of the software is exemplified in an experiment, in which abundance fold-changes of metabolites of the l-arginine biosynthesis in C. glutamicum type strain ATCC 13032 and l-arginine producing strain ATCC 21831 are compared. Furthermore, the capability for detection and annotation of uncommon large neutral losses is shown by the identification of (γ-glutamyl dipeptides in

The synthesis of the 14C and 2H-isotopomers of (R)-N-[2-(2'-ethoxyphenoxy)-ethyl]-N-2-[3-(4'-methoxy-3'-sulfonamido)-phenyl ]-propylamine hydrochloride, an α1-adrenoreceptor antagonist

International Nuclear Information System (INIS)

Wheeler, W.J.; Schmiegel, K.K.; Hunden, D.C.

1989-01-01

The synthesis of [ 14 C]- and [ 2 H]-labeled LY253351 (YM12617-1), a potent α 1 -receptor antagonist, which is potentially useful in the treatment of benign prostatic hypertrophy (BPH) is described. The [ 14 C]-isotopomer was synthesized from [ 14 C]-potassium cyanide in nine steps in 1.5% radiochemical yield. One of the key intermediates, [ 14 C]-4-methoxyphenylacetone, was synthesized from [ 14 C]-4-methoxyphenylacetyl chloride by a Pd(0)-catalyzed reaction with tetramethylstannane. The [ 2 H]-labeled material was synthesized by a Pd/C catalyzed reductive amination with deuterium gas. (author)

Distributed magnetic field positioning system using code division multiple access

Science.gov (United States)

Prigge, Eric A. (Inventor)

2003-01-01

An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

Functional Representation for the Born-Oppenheimer Diagonal Correction and Born-Huang Adiabatic Potential Energy Surfaces for Isotopomers of H3

International Nuclear Information System (INIS)

Mielke, Steven L.; Schwenke, David; Schatz, George C.; Garrett, Bruce C.; Peterson, Kirk A.

2009-01-01

Multireference configuration interaction (MRCI) calculations of the Born-Oppenheimer diagonal correction (BODC) for H3 were performed at 1397 symmetry-unique configurations using the Born-Huang approach; isotopic substitution leads to 4041 symmetry-unique configurations for the DH2 mass combination. These results were then fit to a functional form that permits calculation of the BODC for any combination of isotopes. Mean unsigned fitting errors on a test grid of configurations not included in the fitting process were 0.14, 0.12, and 0.65 cm-1 for the H3, DH2, and MuH2 isotopomers, respectively. This representation can be combined with any Born-Oppenheimer potential energy surface (PES) to yield Born-Huang (BH) PESs; herein we choose the CCI potential energy surface, the uncertainties of which (∼0.01 kcal/mol) are much smaller than the magnitude of the BODC. FORTRAN routines to evaluate these BH surfaces are provided. Variational transition state theory calculations are presented comparing thermal rate constants for reactions on the BO and BH surfaces to provide an initial estimate of the significance of the diagonal correction for the dynamics.

Spatial Variations in N2O Concentration and Isotopomer Composition off the Peru Coast

Science.gov (United States)

Bourbonnais, A.; Letscher, R. T.; Kock, A.; Bange, H. W.; Altabet, M. A.

2016-02-01

Nitrous oxide (N2O) is a potent greenhouse gas and stratospheric ozone depleting substance. The ocean is an important source of N2O to the atmosphere, accounting for up to about 30% of total emissions. However, the factors controlling N2O production and consumption in oceanic environments are still not understood nor constrained. N2O is a by-product of aerobic nitrification, and is formed by two different pathways: 1) the decomposition of hydroxylamine, an intermediate during ammonium oxidation to nitrite, or 2) the reduction of nitrite to N2O (nitrifier-denitrification). N2O is also an intermediate during denitrification under anoxic conditions. In this study, we measured N2O concentrations and isotopomer ratios, as well as O2, nutrient and biogenic N2 concentrations and the isotopic compositions of nitrate, nitrite and biogenic N2 at several coastal stations during two cruises off the Peru coast (6-14°S, 75-81°W) in December 2012 and January 2013. [N2O] varied from below equilibrium values in the OMZ to up to 238 nmol L-1 at 11 m depth at one of the shallowest stations. The isotopic composition of N2O (bulk δ15N: -5 to 30‰, δ18O: 41 to 95‰, and Site Preference: -3 to 65‰) also varied widely, with important differences between stations. Our results show a strong spatial heterogeneity in the mechanisms controlling N2O production and consumption in coastal upwelling regions, which should be taken into account in oceanic N2O models. We will discuss the contributions from different N2O production processes responsible for the observed extreme N2O accumulations.

Quantum tunneling recombination in a system of randomly distributed trapped electrons and positive ions.

Science.gov (United States)

Pagonis, Vasilis; Kulp, Christopher; Chaney, Charity-Grace; Tachiya, M

2017-09-13

During the past 10 years, quantum tunneling has been established as one of the dominant mechanisms for recombination in random distributions of electrons and positive ions, and in many dosimetric materials. Specifically quantum tunneling has been shown to be closely associated with two important effects in luminescence materials, namely long term afterglow luminescence and anomalous fading. Two of the common assumptions of quantum tunneling models based on random distributions of electrons and positive ions are: (a) An electron tunnels from a donor to the nearest acceptor, and (b) the concentration of electrons is much lower than that of positive ions at all times during the tunneling process. This paper presents theoretical studies for arbitrary relative concentrations of electrons and positive ions in the solid. Two new differential equations are derived which describe the loss of charge in the solid by tunneling, and they are solved analytically. The analytical solution compares well with the results of Monte Carlo simulations carried out in a random distribution of electrons and positive ions. Possible experimental implications of the model are discussed for tunneling phenomena in long term afterglow signals, and also for anomalous fading studies in feldspars and apatite samples.

Two-dimensional potential and charge distributions of positive surface streamer

International Nuclear Information System (INIS)

Tanaka, Daiki; Matsuoka, Shigeyasu; Kumada, Akiko; Hidaka, Kunihiko

2009-01-01

Information on the potential and the field profile along a surface discharge is required for quantitatively discussing and clarifying the propagation mechanism. The sensing technique with a Pockels crystal has been developed for directly measuring the potential and electric field distribution on a dielectric material. In this paper, the Pockels sensing system consists of a pulse laser and a CCD camera for measuring the instantaneous two-dimensional potential distribution on a 25.4 mm square area with a 50 μm sampling pitch. The temporal resolution is 3.2 ns which is determined by the pulse width of the laser emission. The transient change in the potential distribution of a positive surface streamer propagating in atmospheric air is measured with this system. The electric field and the charge distributions are also calculated from the measured potential profile. The propagating direction component of the electric field near the tip of the propagating streamer reaches 3 kV mm -1 . When the streamer stops, the potential distribution along a streamer forms an almost linear profile with the distance from the electrode, and its gradient is about 0.5 kV mm -1 .

Energy distribution extraction of negative charges responsible for positive bias temperature instability

International Nuclear Information System (INIS)

Ren Shang-Qing; Yang Hong; Wang Wen-Wu; Tang Bo; Tang Zhao-Yun; Wang Xiao-Lei; Xu Hao; Luo Wei-Chun; Zhao Chao; Yan Jiang; Chen Da-Peng; Ye Tian-Chun

2015-01-01

A new method is proposed to extract the energy distribution of negative charges, which results from electron trapping by traps in the gate stack of nMOSFET during positive bias temperature instability (PBTI) stress based on the recovery measurement. In our case, the extracted energy distribution of negative charges shows an obvious dependence on energy, and the energy level of the largest energy density of negative charges is 0.01 eV above the conduction band of silicon. The charge energy distribution below that energy level shows strong dependence on the stress voltage. (paper)

Formation of H_2^+ and its Isotopomers by Radiative Association: the Role of Shape and Feshbach Resonances

Science.gov (United States)

Beyer, Maximilian; Merkt, Frederic

2017-06-01

The recent observations [1,2] of shape and Feshbach resonances in the high-resolution photoelectron spectra of H_2, HD and D_2 in the vicinity of the dissociation thresholds of H_2^+, HD^+ and D_2^+ raise questions concerning their potential role in the formation of H_2^+ and its isotopomers in the early universe by radiative association, a topic of astrophysical interest [3]. Close-coupling calculations for the cross sections of the reactions {H}^+ + {H} &\\to {H}_2^+ + hν {H}^+ + {D} &\\to {HD}^+ + hν {D}^+ + {H} &\\to {HD}^+ + hν {D}^+ + {D} &\\to {D}_2^+ + hν, will be presented which take into account nonadiabatic couplings involving rovibronic and hyperfine interactions, as well as relativistic and radiative corrections. The calculated energies and widths will be compared with the experimental results of Ref. [1,2] for H_2^+ and new data for HD^+ and D_2^+. The effect of the resonances on the radiative association rate coefficients will be discussed, also in comparison with earlier studies [4]. [1] M. Beyer and F. Merkt, Phys. Rev. Lett. 116, 093001 (2016). [2] M. Beyer and F. Merkt, J. Mol. Spectrosc. 330, 147 (2016). [3] Molecule formation in dust-poor environments, J. F. Babb and K. P. Kirby, in "The molecular astrophysics of stars and galaxies", T. W. Hartquist and D. A. Williams, eds., Oxford University Press, Oxford, 1998, pp. 11-34. [4] D. E. Ramaker and J. M. Peek, Phys. Rev. A 13, 58 (1976).

Gaseous emissions from biogas-digestate management and from fertilized soils. A study with special reference to nitrous oxide determination by stable isotope and isotopomer techniques

International Nuclear Information System (INIS)

Koester, Jan Reent

2014-01-01

Biogas production from energy crops and organic residues for generating electricity is promoted in several European countries to reduce greenhouse gas (GHG) emissions from fossil fuels and thus to slow down global warming and climate change. However, significant GHG (in particular methane, CH_4, and nitrous oxide, N_2O) as well as ammonia (NH_3) emissions may occur from anaerobic digestates (AD), the residues of the biogas production process, during storage periods prior to land spreading as organic fertilizers, when these storage facilities are not covered. In the present study, Open Path FTIR as a non invasive remote sensing technique in combination with the micrometeorological bLS model was successfully evaluated upon its applicability at open AD lagoons, and emissions from two lagoons were determined in several trials. Emissions were found to be dominated by CH_4 and NH_3, reducing the GHG savings of biogas energy considerably. During AD land spreading significant trace gas amounts can be emitted to the atmosphere, which are usually dominated by NH_3. During winter, these emissions are often considered to be low; however, in the present study it was shown that NH_3 emissions under cold temperature conditions can be significant, especially when the soil is frozen and AD infiltration is hampered. AD applied to soil as organic fertilizer may increase N_2O emissions, which derive from biochemical N transformation processes. N_2O as well as N_2 emissions after AD and cattle slurry application to soil have been investigated in an incubation study, indicating lower N_2O and N_2 emissions via denitrification from AD treated soil due to its lower carbon content. N_2O source apportioning in such studies is crucial for improving process understanding and advancing mitigation strategies. The analysis of the different N_2O isotopomer species with particular focus on the intramolecular "1"5N distribution within the asymmetric N_2O molecules (the so called 'site preference

On positivity of parton distributions

International Nuclear Information System (INIS)

Altarelli, G.; Forte, S.; Ridolfi, G.

1998-01-01

We discuss the bounds on polarized parton distributions which follow from their definition in terms of cross section asymmetries. We spell out how the bounds obtained in the naive parton model can be derived within perturbative QCD at leading order when all quark and gluon distributions are defined in terms of suitable physical processes. We specify a convenient physical definition for the polarized and unpolarized gluon distributions in terms of Higgs production from gluon fusion. We show that these bounds are modified by subleading corrections, and we determine them up to NLO. We examine the ensuing phenomenological implications, in particular in view of the determination of the polarized gluon distribution. (orig.)

On positivity of parton distributions

CERN Document Server

Altarelli, Guido; Ridolfi, G; Altarelli, Guido; Forte, Stefano; Ridolfi, Giovanni

1998-01-01

We discuss the bounds on polarized parton distributions which follow from their definition in terms of cross section asymmetries. We spell out how the bounds obtained in the naive parton model can be derived within perturbative QCD at leading order when all quark and gluon distributions are defined in terms of suitable physical processes. We specify a convenient physical definition for the polarized and unpolarized gluon distributions in terms of Higgs production from gluon fusion. We show that these bounds are modified by subleading corrections, and we determine them up to NLO. We examine the ensuing phenomenological implications, in particular in view of the determination of the polarized gluon distribution.

POSITIVE SOLUTIONS TO TWO TYPES OF NEUTRAL DIFFERENTIAL EQUATIONS WITH DISTRIBUTED DELAY

Institute of Scientific and Technical Information of China (English)

无

2012-01-01

In this paper, we study two types of neutral functional differential equations with finite or unbounded distributed deviating arguments. By Banach contraction princi-ple, we obtain some sufficient conditions for the existence of positive solutions to such equations.

The influence of patient positioning uncertainties in proton radiotherapy on proton range and dose distributions

Energy Technology Data Exchange (ETDEWEB)

Liebl, Jakob, E-mail: jakob.liebl@medaustron.at [EBG MedAustron GmbH, 2700 Wiener Neustadt (Austria); Francis H. Burr Proton Therapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States); Department of Therapeutic Radiology and Oncology, Medical University of Graz, 8036 Graz (Austria); Paganetti, Harald; Zhu, Mingyao; Winey, Brian A. [Francis H. Burr Proton Therapy Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

2014-09-15

Purpose: Proton radiotherapy allows radiation treatment delivery with high dose gradients. The nature of such dose distributions increases the influence of patient positioning uncertainties on their fidelity when compared to photon radiotherapy. The present work quantitatively analyzes the influence of setup uncertainties on proton range and dose distributions. Methods: Thirty-eight clinical passive scattering treatment fields for small lesions in the head were studied. Dose distributions for shifted and rotated patient positions were Monte Carlo-simulated. Proton range uncertainties at the 50%- and 90%-dose falloff position were calculated considering 18 arbitrary combinations of maximal patient position shifts and rotations for two patient positioning methods. Normal tissue complication probabilities (NTCPs), equivalent uniform doses (EUDs), and tumor control probabilities (TCPs) were studied for organs at risk (OARs) and target volumes of eight patients. Results: The authors identified a median 1σ proton range uncertainty at the 50%-dose falloff of 2.8 mm for anatomy-based patient positioning and 1.6 mm for fiducial-based patient positioning as well as 7.2 and 5.8 mm for the 90%-dose falloff position, respectively. These range uncertainties were correlated to heterogeneity indices (HIs) calculated for each treatment field (38% < R{sup 2} < 50%). A NTCP increase of more than 10% (absolute) was observed for less than 2.9% (anatomy-based positioning) and 1.2% (fiducial-based positioning) of the studied OARs and patient shifts. For target volumes TCP decreases by more than 10% (absolute) occurred in less than 2.2% of the considered treatment scenarios for anatomy-based patient positioning and were nonexistent for fiducial-based patient positioning. EUD changes for target volumes were up to 35% (anatomy-based positioning) and 16% (fiducial-based positioning). Conclusions: The influence of patient positioning uncertainties on proton range in therapy of small lesions

Gaseous emissions from biogas-digestate management and from fertilized soils. A study with special reference to nitrous oxide determination by stable isotope and isotopomer techniques

Energy Technology Data Exchange (ETDEWEB)

Koester, Jan Reent

2014-07-02

distribution within the asymmetric N{sub 2}O molecules (the so called 'site preference', SP) allows some insights into these source processes. Here, this approach confirmed denitrification as the predominating N{sub 2}O source. The isotopic fractionation factors during N{sub 2}O production and reduction via denitrification are still an uncertainty factor for stable isotope approaches relying on isotope ratios at natural abundance level. Therefore, these fractionation factors have been further investigated using different soil incubation approaches in two studies. The observed isotope fractionation during these experiments was partly in agreement with previous studies; however, in some cases the results deviated from literature values, probably due to experimental artefacts in some of the previous studies. N{sub 2}O Isotopomer analysis is commonly done by isotope ratio mass spectrometry (IRMS), which has relatively low throughput and does not allow real time analysis. Here, recently developed laser spectroscopic techniques capable of site specific N{sub 2}O {sup 15}N analysis may provide significant advantages compared to IRMS. Therefore, an experimental setup involving a new QCL absorption spectrometer was tested for its applicability in soil studies. The SP values of soil derived N{sub 2}O were successfully determined continuously over several days, and were in good agreement with IRMS analysis, presenting laser spectroscopy as a promising new analytical approach for analyzing N{sub 2}O in soil studies.

Enhanced photosynthetic efficiency in trees world-wide by rising atmospheric CO2 levels

Science.gov (United States)

Ehlers, Ina; Wieloch, Thomas; Groenendijk, Peter; Vlam, Mart; van der Sleen, Peter; Zuidema, Pieter A.; Robertson, Iain; Schleucher, Jürgen

2014-05-01

The atmospheric CO2 concentration is increasing rapidly due to anthropogenic emissions but the effect on the Earth's biosphere is poorly understood. The ability of the biosphere to fix CO2 through photosynthesis will determine future atmospheric CO2 concentrations as well as future productivity of crops and forests. Manipulative CO2 enrichment experiments (e.g. FACE) are limited to (i) short time spans, (ii) few locations and (iii) large step increases in [CO2]. Here, we apply new stable isotope methodology to tree-ring archives, to study the effect of increasing CO2 concentrations retrospectively during the past centuries. We cover the whole [CO2] increase since industrialization, and sample trees with global distribution. Instead of isotope ratios of whole molecules, we use intramolecular isotope distributions, a new tool for tree-ring analysis with decisive advantages. In experiments on annual plants, we have found that the intramolecular distribution of deuterium (equivalent to ratios of isotopomer abundances) in photosynthetic glucose depends on growth [CO2] and reflects the metabolic flux ratio of photosynthesis to photorespiration. By applying this isotopomer methodology to trees from Oak Ridge FACE experiment, we show that this CO2 response is present in trees on the leaf level. This CO2 dependence constitutes a physiological signal, which is transferred to the wood of the tree rings. In trees from 13 locations on all continents the isotopomer ratio of tree-ring cellulose is correlated to atmospheric [CO2] during the past 200 years. The shift of the isotopomer ratio is universal for all 12 species analyzed, including both broad-leafed trees and conifers. Because the trees originate from sites with widely differing D/H ratios of precipitation, the generality of the response demonstrates that the signal is independent of the source isotope ratio, because it is encoded in an isotopomer abundance ratio. This decoupling of climate signals and physiological

On positivity of time-frequency distributions.

NARCIS (Netherlands)

Janssen, A.J.E.M.; Claasen, T.A.C.M.

1985-01-01

Consideration is given to the problem of how to regard the fundamental impossibility with time-frequency energy distributions of Cohen's class always to be nonnegative and, at the same time, to have correct marginal distributions. It is shown that the Wigner distribution is the only member of a

Influence of the catheter-top-position upon the distribution pattern of continuous intra-arterially infused chemotherapeutic agent

International Nuclear Information System (INIS)

Ichinohe, Hyobu

1980-01-01

The whole body scanning showed the distribution pattern of infused drug in continuous intra-arterially infused chemotherapy by using a gamma camera and infused RI (sup(99m)Tc-MAA) from catheter. I measured the whole body scanning counts without shield (A) and with lead shield (B) on ROI and natural back ground counts (BG). Then I calculated the distribution ratio on ROI as following. [(A-B)/(A-BG)] x 100(%). It was easy to find a certain relation between the catheter-top-position and the distribution ratio. As a result of investigating data, there were about 4 catheter-top-positions in aorta. Case by case, we putted the catheter-top in better position and prevented technical side effects and measured roughly total dose on ROI. (author)

Distributed transition-edge sensors for linearized position response in a phonon-mediated X-ray imaging spectrometer

Science.gov (United States)

Cabrera, Blas; Brink, Paul L.; Leman, Steven W.; Castle, Joseph P.; Tomada, Astrid; Young, Betty A.; Martínez-Galarce, Dennis S.; Stern, Robert A.; Deiker, Steve; Irwin, Kent D.

2004-03-01

For future solar X-ray satellite missions, we are developing a phonon-mediated macro-pixel composed of a Ge crystal absorber with four superconducting transition-edge sensors (TES) distributed on the backside. The X-rays are absorbed on the opposite side and the energy is converted into phonons, which are absorbed into the four TES sensors. By connecting together parallel elements into four channels, fractional total energy absorbed between two of the sensors provides x-position information and the other two provide y-position information. We determine the optimal distribution for the TES sub-elements to obtain linear position information while minimizing the degradation of energy resolution.

Revisiting the metathesis of 13C-monolabeled ethane

KAUST Repository

Maury, Olivier; Lefort, Laurent; Vidal, Vé ronique; Thivolle-Cazat, Jean; Basset, Jean-Marie

2010-01-01

The metathesis of 13C-monolabeled ethane leads to the parallel occurrence of degenerate and productive reactions, affording the statistical distribution of the various product isotopomers, which can be rationalized in terms of a mechanistic reaction

A CLASS OF DISTRIBUTION-FREE TESTS FOR INDEPENDENCE AGAINST POSITIVE QUADRANT DEPENDENCE

Directory of Open Access Journals (Sweden)

Parameshwar V Pandit

2014-02-01

Full Text Available A class of distribution-free tests based on convex combination of two U-statistics is considered for testing independence against positive quadrant dependence. The class of tests proposed by Kochar and Gupta (1987 and Kendall’s test are members of the proposed class. The performance of the proposed class is evaluated in terms of Pitman asymptotic relative efficiency for Block- Basu (1974 model and Woodworth family of distributions. It has been observed that some members of the class perform better than the existing tests in the literature.  Unbiasedness and consistency of the proposed class of tests have been established.

Descriptive Study of Electromagnetic Wave Distribution for Various Seating Positions: Using Digital Textbooks

Science.gov (United States)

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-01-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in…

Positivity bounds on double parton distributions

International Nuclear Information System (INIS)

Diehl, Markus; Kasemets, Tomas

2013-03-01

Double hard scattering in proton-proton collisions is described in terms of double parton distributions. We derive bounds on these distributions that follow from their interpretation as probability densities, taking into account all possible spin correlations between two partons in an unpolarized proton. These bounds constrain the size of the polarized distributions and can for instance be used to set upper limits on the effects of spin correlations in double hard scattering. We show that the bounds are stable under leading-order DGLAP evolution to higher scales.

The distribution characteristics of pollutants released at different cross-sectional positions of a river

International Nuclear Information System (INIS)

Huang Heqing; Chen Guang; Zhang Qianfeng

2010-01-01

The distribution characteristics of heavier or lighter pollutants released at different cross-sectional positions of a wide river is investigated with a well-tested three-dimensional numerical model of gravity flows based on Reynolds-Averaged Navier-Stokes equations and turbulence k-ε model. By focusing on investigating the influences of flow and buoyancy on pollutants, it is found that while carrying by the river flow downstream: i) a heavier pollutant released from the cross-sectional side position, forms transverse oscillation between two banks with decreased amplitude, i.e. forms kind of helical flow pattern along the straight part of channel bed; ii) a heavier pollutant released from the cross-sectional middle position, forms collapse oscillation in the middle of the straight channel part with reduced amplitude; iii) in the downstream sinuous channel, heavier pollutant is of higher concentration on the outer side of channel bends; iv) a light pollutant released from the cross-sectional side position, slips partly to the other side of the river, resulting in higher concentrations on two sides of the channel top; v) a light pollutant released from the cross-sectional middle position, splits into two parts symmetrically along two sides of the channel top; vi) in the downstream sinuous channel, light pollutant presents higher concentration on the inner side of channel bends. These findings may assist in cost-effective scientific countermeasures to be taken for accidental or planned pollutant releases into a river. - The distribution characteristics of heavier or lighter pollutants released at different cross-sectional positions of a river.

Positivity of time-frequency distribution functions

NARCIS (Netherlands)

Janssen, A.J.E.M.

1988-01-01

This paper deals with the question how various 'natural' conditions posed on time-frequency distribution functions prevent them to be nonnegative everywhere for all signals. The attention is restricted mainly to distribution functions that involve the signal bilinearly. This paper summarizes and

Positive concept of using Roll containers in consumer goods distribution

Directory of Open Access Journals (Sweden)

Miličić Milica B.

2016-01-01

Full Text Available Most of the products, at some point in the transport and logistics processes are carried on pallets. To meet the requirements of heterogeneous goods in the supply chain, pallet underwent certain modifications. The new pallet found application due to its specific characteristics (in terms of shape and dimensions (design, the material from which it is made, positive impact on the environment, ease the recycling process, ease of manipulation within the transport-manipulative processes and economy. The aim is to present the mentioned characteristics of roll containers for which this type of pallet has been used in large distribution chains-supermarkets.

Effects on Subtalar Joint Stress Distribution After Cannulated Screw Insertion at Different Positions and Directions.

Science.gov (United States)

Yuan, Cheng-song; Chen, Wan; Chen, Chen; Yang, Guang-hua; Hu, Chao; Tang, Kang-lai

2015-01-01

We investigated the effects on subtalar joint stress distribution after cannulated screw insertion at different positions and directions. After establishing a 3-dimensional geometric model of a normal subtalar joint, we analyzed the most ideal cannulated screw insertion position and approach for subtalar joint stress distribution and compared the differences in loading stress, antirotary strength, and anti-inversion/eversion strength among lateral-medial antiparallel screw insertion, traditional screw insertion, and ideal cannulated screw insertion. The screw insertion approach allowing the most uniform subtalar joint loading stress distribution was lateral screw insertion near the border of the talar neck plus medial screw insertion close to the ankle joint. For stress distribution uniformity, antirotary strength, and anti-inversion/eversion strength, lateral-medial antiparallel screw insertion was superior to traditional double-screw insertion. Compared with ideal cannulated screw insertion, slightly poorer stress distribution uniformity and better antirotary strength and anti-inversion/eversion strength were observed for lateral-medial antiparallel screw insertion. Traditional single-screw insertion was better than double-screw insertion for stress distribution uniformity but worse for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion was slightly worse for stress distribution uniformity than was ideal cannulated screw insertion but superior to traditional screw insertion. It was better than both ideal cannulated screw insertion and traditional screw insertion for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion is an approach with simple localization, convenient operation, and good safety. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Stable isotope-resolved analysis with quantitative dissolution dynamic nuclear polarization

DEFF Research Database (Denmark)

Lerche, Mathilde Hauge; Yigit, Demet; Frahm, Anne Birk

2018-01-01

Metabolite profiles and their isotopomer distributions can be studied non-invasively in complex mixtures with NMR. The advent of dissolution Dynamic Nuclear Polarization (dDNP) and isotope enrichment add sensitivity and resolution to such met-abolic studies. Metabolic pathways and networks can be...

Acute inhibition of hepatic glucose-6-phosphatase does not affect gluconeogenesis but directs gluconeogenic flux toward glycogen in fasted rats. A pharmacological study with the chlorogenic acid derivative S4048

NARCIS (Netherlands)

van Dijk, T. H.; van der Sluijs, F. H.; Wiegman, C. H.; Baller, J. F.; Gustafson, L. A.; Burger, H. J.; Herling, A. W.; Kuipers, F.; Meijer, A. J.; Reijngoud, D. J.

2001-01-01

Effects of acute inhibition of glucose-6-phosphatase activity by the chlorogenic acid derivative S4048 on hepatic carbohydrate fluxes were examined in isolated rat hepatocytes and in vivo in rats. Fluxes were calculated using tracer dilution techniques and mass isotopomer distribution analysis in

Acute inhibition of hepatic glucose-6-phosphatase does not affect gluconeogenesis but directs gluconeogenic flux toward glycogen in fasted rats - A pharmacological study with the chlorogenic acid derivative S4048

NARCIS (Netherlands)

van Dijk, TH; van der Sluijs, FH; Wiegman, CH; Baller, JFW; Gustafson, LA; Burger, HJ; Herling, AW; Kuipers, F; Meijer, AJ; Reijngoud, DJ

2001-01-01

Effects of acute inhibition of glucose-6-phosphatase activity by the chlorogenic acid derivative S4048 on hepatic carbohydrate fluxes were examined in isolated rat hepatocytes and in vivo in rats. Fluxes were calculated using tracer dilution techniques and mass isotopomer distribution analysis in

Revisiting the metathesis of 13C-monolabeled ethane

KAUST Repository

Maury, Olivier

2010-12-13

The metathesis of 13C-monolabeled ethane leads to the parallel occurrence of degenerate and productive reactions, affording the statistical distribution of the various product isotopomers, which can be rationalized in terms of a mechanistic reaction scheme combining both processes. © 2010 American Chemical Society.

SU-F-T-24: Impact of Source Position and Dose Distribution Due to Curvature of HDR Transfer Tubes

Energy Technology Data Exchange (ETDEWEB)

Khan, A; Yue, N [Rutgers University, New Brunswick, NJ (United States)

2016-06-15

Purpose: Brachytherapy is a highly targeted from of radiotherapy. While this may lead to ideal dose distributions on the treatment planning system, a small error in source location can lead to change in the dose distribution. The purpose of this study is to quantify the impact on source position error due to curvature of the transfer tubes and the impact this may have on the dose distribution. Methods: Since the source travels along the midline of the tube, an estimate of the positioning error for various angles of curvature was determined using geometric properties of the tube. Based on the range of values a specific shift was chosen to alter the treatment plans for a number of cervical cancer patients who had undergone HDR brachytherapy boost using tandem and ovoids. Impact of dose to target and organs at risk were determined and checked against guidelines outlined by radiation oncologist. Results: The estimate of the positioning error was 2mm short of the expected position (the curved tube can only cause the source to not reach as far as with a flat tube). Quantitative impact on the dose distribution is still in the process of being analyzed. Conclusion: The accepted positioning tolerance for the source position of a HDR brachytherapy unit is plus or minus 1mm. If there is an additional 2mm discrepancy due to tube curvature, this can result in a source being 1mm to 3mm short of the expected location. While we do always attempt to keep the tubes straight, in some cases such as with tandem and ovoids, the tandem connector does not extend as far out from the patient so the ovoid tubes always contain some degree of curvature. The dose impact of this may be significant.

Distributed Position-Based Consensus of Second-Order Multiagent Systems With Continuous/Intermittent Communication.

Science.gov (United States)

Song, Qiang; Liu, Fang; Wen, Guanghui; Cao, Jinde; Yang, Xinsong

2017-04-24

This paper considers the position-based consensus in a network of agents with double-integrator dynamics and directed topology. Two types of distributed observer algorithms are proposed to solve the consensus problem by utilizing continuous and intermittent position measurements, respectively, where each observer does not interact with any other observers. For the case of continuous communication between network agents, some convergence conditions are derived for reaching consensus in the network with a single constant delay or multiple time-varying delays on the basis of the eigenvalue analysis and the descriptor method. When the network agents can only obtain intermittent position data from local neighbors at discrete time instants, the consensus in the network without time delay or with nonuniform delays is investigated by using the Wirtinger's inequality and the delayed-input approach. Numerical examples are given to illustrate the theoretical analysis.

Bilinear phase-plane distribution functions and positivity

NARCIS (Netherlands)

Janssen, A.J.E.M.

1985-01-01

There is a theorem of Wigner that states that phase-plane distribution functions involving the state bilinearly and having correct marginals must take negative values for certain states. The purpose of this paper is to support the statement that these phase-plane distribution functions are for

Method for uniformly distributing carbon flakes in a positive electrode, the electrode made thereby and compositions. [Patent application

Science.gov (United States)

Mrazek, F.C.; Smaga, J.A.; Battles, J.E.

1981-01-19

A positive electrode for a secondary electrochemical cell is described wherein an electrically conductive current collector is in electrical contact with a particulate mixture of gray cast iron and an alkali metal sulfide and an electrolyte including alkali metal halides or alkaline earth metal halides. Also present may be a transition metal sulfide and graphite flakes from the conversion of gray cast iron to iron sulfide. Also disclosed is a method of distributing carbon flakes in a cell wherein there is formed an electrochemical cell of a positive electrode structure of the type described and a suitable electrolyte and a second electrode containing a material capable of alloying with alkali metal ions. The cell is connected to a source of electrical potential to electrochemically convert gray cast iron to an iron sulfide and uniformly to distribute carbon flakes formerly in the gray cast iron throughout the positive electrode while forming an alkali metal alloy in the negative electrode. Also disclosed are compositions useful in preparing positive electrodes.

Mid-ventilation position planning: Optimal model for dose distribution in lung tumour

International Nuclear Information System (INIS)

Benchalal, M.; Leseur, J.; Chajon, E.; Cazoulat, G.; Haigron, P.; Simon, A.; Bellec, J.; Lena, H.; Crevoisier, R. de

2012-01-01

Purpose. - The dose distribution for lung tumour is estimated using a 3D-CT scan, and since a person breathes while the images are captured, the dose distribution doesn't reflect the reality. A 4D-CT scan integrates the motion of the tumour during breathing and, therefore, provides us with important information regarding tumour's motion in all directions, the motion volume (ITV) and the time-weighted average position (MVP). Patient and methods. - Based on these two concepts, we have estimated, for a lung carcinoma case a 3D dose distribution from a 3D-CT scan, and a 4D dose distribution from a 4-D CT scan. To this, we have applied a non-rigid registration to estimate the cumulative dose. Results. - Our study shows that the 4D dose estimation of the GTV is almost the same when made using MVP and ITV concepts, but sparring of the healthy lung is better done using the MPV model (MVP), as compared to the ITV model. This improvement of the therapeutic index allows, from a projection on the theoretical maximal dose to PTV (strictly restricted to doses for the lungs and the spinal cord), for an increase of about 11% on the total dose (maximal dose of 86 Gy for the ITV and 96 Gy for the MVP). Conclusion. - Further studies with more patients are needed to confirm our data. (authors)

Distribution of events of positive selection and population differentiation in a metabolic pathway: the case of asparagine N-glycosylation

Directory of Open Access Journals (Sweden)

Dall’Olio Giovanni

2012-06-01

Full Text Available Abstract Background Asparagine N-Glycosylation is one of the most important forms of protein post-translational modification in eukaryotes. This metabolic pathway can be subdivided into two parts: an upstream sub-pathway required for achieving proper folding for most of the proteins synthesized in the secretory pathway, and a downstream sub-pathway required to give variability to trans-membrane proteins, and involved in adaptation to the environment and innate immunity. Here we analyze the nucleotide variability of the genes of this pathway in human populations, identifying which genes show greater population differentiation and which genes show signatures of recent positive selection. We also compare how these signals are distributed between the upstream and the downstream parts of the pathway, with the aim of exploring how forces of population differentiation and positive selection vary among genes involved in the same metabolic pathway but subject to different functional constraints. Results Our results show that genes in the downstream part of the pathway are more likely to show a signature of population differentiation, while events of positive selection are equally distributed among the two parts of the pathway. Moreover, events of positive selection are frequent on genes that are known to be at bifurcation points, and that are identified as being in key position by a network-level analysis such as MGAT3 and GCS1. Conclusions These findings indicate that the upstream part of the Asparagine N-Glycosylation pathway has lower diversity among populations, while the downstream part is freer to tolerate diversity among populations. Moreover, the distribution of signatures of population differentiation and positive selection can change between parts of a pathway, especially between parts that are exposed to different functional constraints. Our results support the hypothesis that genes involved in constitutive processes can be expected to show

SU-E-T-324: The Influence of Patient Positioning Uncertainties in Proton Radiotherapy On Proton Range and Dose Distributions

Energy Technology Data Exchange (ETDEWEB)

Liebl, J [EBG MedAustron GmbH, Wiener Neustadt (Austria); Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Medical University of Graz, Graz (Austria); Paganetti, H; Winey, B [Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)

2014-06-01

Purpose: Proton radiotherapy allows radiation treatment delivery with high dose gradients. The nature of such dose distributions increases the influence of patient positioning uncertainties on their fidelity when compared to photon radiotherapy. The present work quantitatively analyzes the influence of setup uncertainties on proton range and dose distributions. Methods: 38 clinical passive scattering treatment fields for small lesions in the head were studied. Dose distributions for shifted and rotated patient positions were Monte Carlo-simulated. Proton range uncertainties at the 50% and 90%-dose falloff position were calculated considering 18 arbitrary combinations of maximal patient position shifts and rotations for two patient positioning methods. Normal tissue complication probabilities (NTCPs), equivalent uniform doses (EUDs) and tumor control probabilities (TCPs) were studied for organs at risk (OARs) and target volumes of eight patients. Results: We identified a median 1σ proton range uncertainty at the 50%-dose falloff of 2.8 mm for anatomy-based patient positioning and 1.6 mm for fiducial-based patient positioning as well as 7.2 mm and 5.8 mm for the 90%-dose falloff position respectively. These range uncertainties were correlated to heterogeneity indices (HIs) calculated for each treatment field (38% < R{sup 2} < 50%). A NTCP increase of more than 10% (absolute) was observed for less than 2.9% (anatomy-based positioning) and 1.2% (fiducial-based positioning) of the studied OARs and patient shifts. TCP decreases larger than 10% (absolute) were seen for less than 2.2% of the target volumes or non-existent. EUD changes were up to 178% for OARs and 35% for target volumes. Conclusion: The influence of patient positioning uncertainties on proton range in therapy of small lesions in the human brain and target and OAR dosimetry were studied. Observed range uncertainties were correlated with HIs. The clinical practice of using multiple compensator

Retrobiosynthetic NMR studies with 13C-labeled glucose. Formation of gallic acid in plants and fungi

International Nuclear Information System (INIS)

Werner, I.; Bacher, A.; Eisenreich, W.

1997-01-01

The biosynthesis of gallic acid was studied in cultures of the fungus Phycomyces blakesleeanus and in leaves of the tree Rhus typhina. Fungal cultures were grown with [1-13C]glucose or with a mixture of unlabeled glucose and [U-13C6]glucose. Young leaves of R. typhina were kept in an incubation chamber and were supplied with a solution containing a mixture of unlabeled glucose and [U-13C6]glucose via the leaf stem. Isotope distributions in isolated gallic acid and aromatic amino acids were analyzed by one-dimensional 1H and 13C NMR spectroscopy. A quantitative analysis of the complex isotopomer composition of metabolites was obtained by deconvolution of the 13C13C coupling multiplets using numerical simulation methods. This approach required the accurate analysis of heavy isotope chemical shift effects in a variety of different isotopomers and the analysis of long range 13C13C coupling constants. The resulting isotopomer patterns were interpreted using a retrobiosynthetic approach based on a comparison between the isotopomer patterns of gallic acid and tyrosine. The data show that both in the fungus and in the plant all carbon atoms of gallic acid are biosynthetically equivalent to carbon atoms of shikimate. Notably, the carboxylic group of gallic acid is derived from the carboxylic group of an early intermediate of the shikimate pathway and not from the side chain of phenylalanine or tyrosine. It follows that the committed precursor of gallic acid is an intermediate of the shikimate pathway prior to prephenate or arogenate, most probably 5-dehydroshikimate. A formation of gallic acid via phenylalanine, the lignin precursor, caffeic acid, or 3,4, 5-trihydroxycinnamic acid can be ruled out as major pathways in the fungus and in young leaves of R. typhina. The incorporation of uniformly 13C-labeled glucose followed by quantitative NMR analysis of isotopomer patterns is suggested as a general method for biosynthetic studies. As shown by the plant experiment, this

Experimental investigation of quantum key distribution with position and momentum of photon pairs

International Nuclear Information System (INIS)

Almeida, M.P.; Walborn, S.P.; Souto Ribeiro, P.H.

2005-01-01

We investigate the utility of Einstein-Podolsky-Rosen correlations of the position and momentum of photon pairs from parametric down-conversion in the implementation of a secure quantum key distribution protocol. We show that security is guaranteed by the entanglement between down-converted pairs, and can be checked by either direct comparison of Alice and Bob's measurement results or evaluation of an inequality of the sort proposed by Mancini et al. [Phys. Rev. Lett. 88, 120401 (2002)

Filtering for distributed mechanical systems using position measurements: perspectives in medical imaging

International Nuclear Information System (INIS)

Moireau, Philippe; Chapelle, Dominique; Tallec, Patrick Le

2009-01-01

We propose an effective filtering methodology designed to perform estimation in a distributed mechanical system using position measurements. As in a previously introduced method, the filter is inspired by robust control feedback, but here we take full advantage of the estimation specificity to choose a feedback law that can act on displacements instead of velocities and still retain the same kind of dissipativity property which guarantees robustness. This is very valuable in many applications for which positions are more readily available than velocities, as in medical imaging. We provide an in-depth analysis of the proposed procedure, as well as detailed numerical assessments using a test problem inspired by cardiac biomechanics, as medical diagnosis assistance is an important perspective for this approach. The method is formulated first for measurements based on Lagrangian displacements, but we then derive a nonlinear extension allowing us to instead consider segmented images, which of course is even more relevant in medical applications

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends.

Science.gov (United States)

Ruiz-Lopez, Noemi; Stubhaug, Ingunn; Ipharraguerre, Ignacio; Rimbach, Gerald; Menoyo, David

2015-07-10

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic (DHA) acids). However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6%) on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC), showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively) but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG.

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar Fed Vegetable and Fish Oil Blends

Directory of Open Access Journals (Sweden)

Noemi Ruiz-Lopez

2015-07-01

Full Text Available The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA composition and its positional distribution in the triacylglycerol (TAG fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA and docoxahexaenoic (DHA acids. However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6% on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC, showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG.

The effect of temperature and the control rod position on the spatial neutron flux distribution in the Syrian Miniature Neutron Source Reactor

International Nuclear Information System (INIS)

Khattab, K.; Omar, H.; Ghazi, N.

2007-01-01

The effect of water and fuel temperature increase and changes in the control rod positions on the spatial neutron flux distribution in the Syrian Miniature Neutron Source Reactor (MNSR) is discussed. The cross sections of all the reactor components at different temperatures are generated using the WIMSD4 code. These group constants are used then in the CITATION code to calculate the special neutron flux distribution using four energy groups. This work shows that water and fuel temperature increase in the reactor during the reactor daily operating time does not affect the spatial neutron flux distribution in the reactor. Changing the control rod position does not affect as well the spatial neutron flux distribution except in the region around the control rod position. This stability in the spatial neutron flux distribution, especially in the inner and outer irradiation sites, makes MNSR as a good tool for the neutron activation analysis (NAA) technique and production of radioisotopes with medium or short half lives during the reactor daily operating time. (author)

Measurement and analysis of neutron flux distribution of STACY heterogeneous core by position sensitive proportional counter. Contract research

CERN Document Server

Murazaki, M; Uno, Y

2003-01-01

We have measured neutron flux distribution around the core tank of STACY heterogeneous core by position sensitive proportional counter (PSPC) to develop the method to measure reactivity for subcritical systems. The neutron flux distribution data in the position accuracy of +-13 mm have been obtained in the range of uranium concentration of 50g/L to 210g/L both in critical and in subcritical state. The prompt neutron decay constant, alpha, was evaluated from the measurement data of pulsed neutron source experiments. We also calculated distribution of neutron flux and sup 3 He reaction rates at the location of PSPC by using continuous energy Monte Carlo code MCNP. The measurement data was compared with the calculation results. As results of comparison, calculated values agreed generally with measurement data of PSPC with Cd cover in the region above half of solution height, but the difference between calculated value and measurement data was large in the region below half of solution height. On the other hand, ...

Position-specific isotope analysis by on-line pyrolysis coupled to IRMS

Science.gov (United States)

Gilbert, A.; Suda, K.; Yamada, K.; Ueno, Y.; Yoshida, N.

2016-12-01

Position-specific isotopic analyses (PSIA) provide unique information regarding the sources, sinks and processes related to natural molecules. For instance, PSIA of short-chain hydrocarbons could lead to temperature of formation and maturity of natural gas reservoirs [1][2]. In the last decade, quantitative Nuclear Magnetic Resonance (NMR) specrometry has been used for PSIA of organic molecules such as glucose or n-alkanes [3][4]. However, due to its low sensitivity, application to low amount geochemical samples remains challenging. In 1997, Corso & Brenna proposed to adapt a pyrolysis furnace to an isotope ratio mass spectrometer, making it possible the thermal degradation of the target molecule and the subsequent analysis of the d13C values of the fragments formed [5]. Starting from fatty acid methyl esters they demonstrated the absence of rearrangement during pyrolytic degradation and could determine the d13C value of carboxyl C-atom position. We adapted the system for the full characterization of position-specific isotope composition of small molecules (ethanol, acetic acid, alanine, propane). Nanomole amount of sample can be analyzed with a precision on intramolecular d13C values of 1‰ or lower [2]. We recently analyzed abiotic and thermogenic propane samples both from the field and from lab simulations. PSIA of propane shows systematic differences of position-specific isotope composition between thermogenic and abiotic samples. While the former show 13C-depletion on the terminal C-atom position - consistent with thermal cracking kinetic models [6] - abiotic samples show little or no preference for terminal or central 13C-isotopomer. These results emphasize the potential of PSIA to trace the the processes associated with organic molecules production. [1] Piasecki et al. 2016 GCA 188, 58 [2] Gilbert et al. 2016 GCA 177, 205 [3] Gilbert et al. 2012 PNAS, 109, 18204 [4] Gilbert et al. 2013 Org. Geochem, 62, 56 [5] Corso & Brenna 1997 PNAS, 94, 1049 [6] Tang et

Response to 'Comments on the uncertainties in isotope patterns of molecules' by J. Meija and Z. Mester (doi:10.1016/j.aca.2010.09.029)

International Nuclear Information System (INIS)

Garcia Alonso, J.I.; Rodriguez-Gonzalez, P.

2011-01-01

This manuscript presents a response to a recently published article in Analytica Chimica Acta by J. Meija and Z. Mester ( (doi:10.1016/j.aca.2010.09.029)) in which the authors comment on some aspects of our previous work entitled 'Determination of the uncertainties in the theoretical mass isotopomer distribution of molecules' Anal. Chim. Acta 664 (2010) 68-76. We present here new arguments to support our previous findings and to clarify some aspects regarding to the calculation of the uncertainty of isotope patterns. The uncertainty calculations proposed by Meija and Mester for carbon-only clusters have been compared with our previously developed first-order model based on the spreadsheet approach described by Kragten (J. Kragten, Analyst 119 (1994) 2161). The results obtained in this comparison demonstrate that the Kragten procedure can be applied safely for the calculation of the uncertainties in the mass isotopomer distribution of molecules when the u average value is calculated. In addition the procedure provides good results even when the first-order error propagation law failed for some particular cases (C 93 and C 186 clusters).

Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules

Science.gov (United States)

Filatov, Michael; Zou, Wenli; Cremer, Dieter

2012-10-01

The dependence of the nuclear quadrupole coupling constants (NQCC) on the interaction between electrons and a nucleus of finite size is theoretically analyzed. A deviation of the ratio of the NQCCs obtained from two different isotopomers of a molecule from the ratio of the corresponding bare nuclear electric quadrupole moments, known as quadrupole anomaly, is interpreted in terms of the logarithmic derivatives of the electric field gradient at the nuclear site with respect to the nuclear charge radius. Quantum chemical calculations based on a Dirac-exact relativistic methodology suggest that the effect of the changing size of the Au nucleus in different isotopomers can be observed for Au-containing molecules, for which the predicted quadrupole anomaly reaches values of the order of 0.1%. This is experimentally detectable and provides an insight into the charge distribution of non-spherical nuclei.

The distribution of sexually-transmitted Human Papillomaviruses in HIV positive and negative patients in Zambia, Africa

Directory of Open Access Journals (Sweden)

Hause Lara

2007-07-01

Full Text Available Abstract Background Human Papillomaviruses (HPV are double-stranded DNA viruses, considered to be the primary etiological agents in cervical intraepithelial neoplasias and cancers. Approximately 15–20 of the 40 mucosal HPVs confer a high-risk of progression of lesions to invasive cancer. In this study, we investigated the prevalence of sexually transmitted HPVs in Human Immunodeficiency Virus (HIV positive and negative patients in Zambia, Africa. The rate of high-risk HPV genotypes worldwide varies within each country. Thus, we sought to investigate the rates of HPV infection in sub-Saharan Africa and the potential role of HIV in affecting the HPV genotype distribution. Methods This retrospective cross-sectional study reports findings on the association and effects of HIV on HPV infections in an existing cohort of patients at University Teaching Hospital (UTH Lusaka, Zambia. The objective of this study was to assess HPV prevalence, genotype distribution and to identify co-factors that influence HPV infection. Polymerase chain reaction (PCR with two standard consensus primer sets (CpI/II and GP5+/6+ was used to test for the presence of HPV DNA. Primers specific for β-actin were used to monitor DNA quality. Vaginal lavage samples, collected between 1998-1999 from a total of 70 women, were part of a larger cohort that was also analyzed for HIV and human herpesvirus infection. Seventy of the samples yielded usable DNA. HIV status was determined by two rapid assays, Capillus and Determine. The incidence of HIV and HPV infections and HPV genotype distributions were calculated and statistical significance was determined by Chi-Squared test. Results We determined that most common HPV genotypes detected among these Zambian patients were types 16 and 18 (21.6% each, which is approximately three-fold greater than the rates for HPV16, and ten-fold greater than the rates for HPV18 in the United States. The worldwide prevalence of HPV16 is approximately 14

Measurement and analysis of neutron flux distribution of STACY heterogeneous core by position sensitive proportional counter. Contract research

Energy Technology Data Exchange (ETDEWEB)

Murazaki, Minoru; Uno, Yuichi; Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

We have measured neutron flux distribution around the core tank of STACY heterogeneous core by position sensitive proportional counter (PSPC) to develop the method to measure reactivity for subcritical systems. The neutron flux distribution data in the position accuracy of {+-}13 mm have been obtained in the range of uranium concentration of 50g/L to 210g/L both in critical and in subcritical state. The prompt neutron decay constant, {alpha}, was evaluated from the measurement data of pulsed neutron source experiments. We also calculated distribution of neutron flux and {sup 3}He reaction rates at the location of PSPC by using continuous energy Monte Carlo code MCNP. The measurement data was compared with the calculation results. As results of comparison, calculated values agreed generally with measurement data of PSPC with Cd cover in the region above half of solution height, but the difference between calculated value and measurement data was large in the region below half of solution height. On the other hand, calculated value agreed well with measurement data of PSPC without Cd cover. (author)

Moving mesh finite element method for finite time extinction of distributed parameter systems with positive exponential feedback

International Nuclear Information System (INIS)

Garnadi, A.D.

1997-01-01

In the distributed parameter systems with exponential feedback, non-global existence of solution is not always exist. For some positive initial values, there exist finite time T such that the solution goes to infinity, i.e. finite time extinction or blow-up. Here is present a numerical solution using Moving Mesh Finite Element to solve the distributed parameter systems with exponential feedback close to blow-up time. The numerical behavior of the mesh close to the time of extinction is the prime interest in this study

Statistical distribution of hydrogen over three positions in the brucite Mg(OH)2 structure from electron diffractometry data

International Nuclear Information System (INIS)

Zhukhlistov, A.A.; Avilov, A.S.; Ferraris, D.; Zvyagin, B.B.; Plotnikov, V.P.

1997-01-01

The method of improved automatic electron diffractometry for measuring and recording intensities to two-dimensionally distributed reflections of texture-type electron diffraction patterns has been used for the analysis of the brucite Mg(OH) 2 structure. The experimental accuracy of the measured intensities proved to be sufficient for studying fine structural details of the statistical distribution of hydrogen atoms over three structure positions located around the threefold axis of the brucite structure

Clinicopathologic Risk Factor Distributions for MLH1 Promoter Region Methylation in CIMP-Positive Tumors.

Science.gov (United States)

Levine, A Joan; Phipps, Amanda I; Baron, John A; Buchanan, Daniel D; Ahnen, Dennis J; Cohen, Stacey A; Lindor, Noralane M; Newcomb, Polly A; Rosty, Christophe; Haile, Robert W; Laird, Peter W; Weisenberger, Daniel J

2016-01-01

The CpG island methylator phenotype (CIMP) is a major molecular pathway in colorectal cancer. Approximately 25% to 60% of CIMP tumors are microsatellite unstable (MSI-H) due to DNA hypermethylation of the MLH1 gene promoter. Our aim was to determine if the distributions of clinicopathologic factors in CIMP-positive tumors with MLH1 DNA methylation differed from those in CIMP-positive tumors without DNA methylation of MLH1. We assessed the associations between age, sex, tumor-site, MSI status BRAF and KRAS mutations, and family colorectal cancer history with MLH1 methylation status in a large population-based sample of CIMP-positive colorectal cancers defined by a 5-marker panel using unconditional logistic regression to assess the odds of MLH1 methylation by study variables. Subjects with CIMP-positive tumors without MLH1 methylation were significantly younger, more likely to be male, and more likely to have distal colon or rectal primaries and the MSI-L phenotype. CIMP-positive MLH1-unmethylated tumors were significantly less likely than CIMP-positive MLH1-methylated tumors to harbor a BRAF V600E mutation and significantly more likely to harbor a KRAS mutation. MLH1 methylation was associated with significantly better overall survival (HR, 0.50; 95% confidence interval, 0.31-0.82). These data suggest that MLH1 methylation in CIMP-positive tumors is not a completely random event and implies that there are environmental or genetic determinants that modify the probability that MLH1 will become methylated during CIMP pathogenesis. MLH1 DNA methylation status should be taken into account in etiologic studies. ©2015 American Association for Cancer Research.

Clinicopathological risk factor distributions for MLH1 promoter region methylation in CIMP positive tumors

Science.gov (United States)

Levine, A. Joan; Phipps, Amanda I.; Baron, John A.; Buchanan, Daniel D.; Ahnen, Dennis J.; Cohen, Stacey A.; Lindor, Noralane M.; Newcomb, Polly A.; Rosty, Christophe; Haile, Robert W.; Laird, Peter W.; Weisenberger, Daniel J.

2015-01-01

Background The CpG Island Methylator Phenotype (CIMP) is a major molecular pathway in colorectal cancer (CRC). Approximately 25% to 60% of CIMP tumors are microsatellite unstable (MSI-H) due to DNA hypermethylation of the MLH1 gene promoter. Our aim was to determine if the distributions of clinicopathologic factors in CIMP-positive tumors with MLH1 DNA methylation differed from those in CIMP-positive tumors without DNA methylation of MLH1. Methods We assessed the associations between age, sex, tumor-site, MSI status BRAF and KRAS mutations and family CRC history with MLH1 methylation status in a large population-based sample of CIMP-positive CRCs defined by a 5-marker panel using unconditional logistic regression to assess the odds of MLH1 methylation by study variables. Results Subjects with CIMP-positive tumors without MLH1 methylation were significantly younger, more likely to be male, more likely to have distal colon or rectal primaries and the MSI-L phenotype. CIMP-positive MLH1-unmethylated tumors were significantly less likely than CIMP-positive MLH1-methylated tumors to harbor a BRAF V600E mutation and significantly more likely to harbor a KRAS mutation. MLH1 methylation was associated with significantly better overall survival (HR=0.50; 95% Confidence Interval (0.31, 0.82)). Conclusions These data suggest that MLH1 methylation in CIMP-positive tumors is not a completely random event and implies that there are environmental or genetic determinants that modify the probability that MLH1 will become methylated during CIMP pathogenesis. Impact MLH1 DNA methylation status should be taken into account in etiologic studies. PMID:26512054

Molecular dynamics simulation based on the multi-component molecular orbital method: Application to H5O2+,D5O2+,andT5O2+

International Nuclear Information System (INIS)

Ishimoto, Takayoshi; Koyama, Michihisa

2012-01-01

Graphical abstract: Molecular dynamics method based on multi-component molecular orbital method was applied to basic hydrogen bonding systems, H 5 O 2 + , and its isotopomers (D 5 O 2 + andT 5 O 2 + ). Highlights: ► Molecular dynamics method with nuclear quantum effect was developed. ► Multi-component molecular orbital method was used as ab initio MO calculation. ► Developed method applied to basic hydrogen bonding system, H 5 O 2 + , and isotopomers. ► O ⋯ O vibrational stretching reflected to the distribution of protonic wavefunctions. ► H/D/T isotope effect was also analyzed. - Abstract: We propose a molecular dynamics (MD) method based on the multi-component molecular orbital (MC M O) method, which takes into account the quantum effect of proton directly, for the detailed analyses of proton transfer in hydrogen bonding system. The MC M O based MD (MC M O-MD) method is applied to the basic structures, H 5 O 2 + (called “Zundel ion”), and its isotopomers (D 5 O 2 + andT 5 O 2 + ). We clearly demonstrate the geometrical difference of hydrogen bonded O ⋯ O distance induced by H/D/T isotope effect because the O ⋯ O in H-compound was longer than that in D- or T-compound. We also find the strong relation between stretching vibration of O ⋯ O and the distribution of hydrogen bonded protonic wavefunction because the protonic wavefunction tends to delocalize when the O ⋯ O distance becomes short during the dynamics. Our proposed MC M O-MD simulation is expected as a powerful tool to analyze the proton dynamics in hydrogen bonding systems.

Study of position resolution for cathode readout MWPC with measurement of induced charge distribution

International Nuclear Information System (INIS)

Chiba, J.; Iwasaki, H.; Kageyama, T.; Kuribayashi, S.; Nakamura, K.; Sumiyoshi, T.; Takeda, T.

1983-01-01

A readout technqiue of multiwire proportional chambers by measurement of charges induced on cathode strips, orthogonal to anode wires, requires an algorithm to relate the measured charge distribution to the avalanche position. With given chamber parameters and under the influence of noise, resolution limits depend on the chosen algorithm. We have studied the position resolution obtained by the centroid method and by the charge-ratio method, both using three consecutive cathode strips. While the centroid method uses a single number, the center of gravity of the measured charges, the charge-ratio method uses the ratios of the charges Qsub(i-1)/Qsub(i) and Qsub(i+1)/Qsub(i) where Qsub(i) is the largest. To obtain a given resolution, the charge-ratio method generally allows wider cathode strips and therefore a smaller number of readout channels than the centroid method. (orig.)

Development of a position-sensitive fission counter and measurement of neutron flux distributions

International Nuclear Information System (INIS)

Yamagishi, Hideshi; Soyama, Kazuhiko; Kakuta, Tsunemi

2001-08-01

A position-sensitive fission counter (PSFC) that operates in high neutron flux and high gamma-ray background such as at the side of a power reactor vessel has been developed. Neutron detection using the PSFC with a solenoid electrode is based on a delay-line method. The PSFC that has the outer diameter of 25 mm and the sensitive length of 1000 mm was manufactured for investigation of the performances. The PSFC provided output current pulses that were sufficiently higher than the alpha noise, though the PSFC has a solenoid electrode and large electrode-capacitance. The S/N ratio of PSFC outputs proved to be higher than that of ordinary fission counters with 200 mm sensitive length. A performance test to measure neutron flux distributions by a neutron measuring system with the PSFC was carried out by the side of a graphite pile, W2.4 x H1.4 x L1.2 m, with neutron sources, Am-Be 370 GBq x 2. It was confirmed that the neutron flux distribution was well measured with the system. (author)

Impact of patient positioning on radiotherapy dose distribution: An assessment in parotid tumor

Directory of Open Access Journals (Sweden)

Seema Sharma

2016-03-01

Full Text Available Purpose: We intended to study the impact of patient positioning on the dose distribution within target volume and organs at risk in patients with parotid malignancies treated with 3D conformal radiotherapy (3D-CRT with photon wedge pair (WP or intensity modulated radiotherapy (IMRT.Methods: Three patients with a non-Hodgkin’s lymphoma of the right parotid gland were consecutively immobilized using thermoplastic cast in 2 positions: supine with head in neutral position (HN and with head turned 90° to the left side (HT. Images for treatment planning purpose were acquired in both positions. For both positions, photon WP plans and 5 field IMRT plans were generated, after contouring clinical target volume (CTV, planning target volume (PTV= CTV + 5 mm margin and organs at risk (OAR. All plans were evaluated for target coverage and dose to OARs.Results: Both CTV and PTV were apparently larger in HN compared with HT (31.76±8.89 cc, 30.31±7.83 cc and 62.49±19.01 cc, 58.89±15.33 cc respectively. The CI value for PTV was slightly better for HT compared to HN position in both the WP and IMRT plans. The homogeneity was comparable in both the head positions in case of WP plan. The mean HI of PTV was increased in case of IMRT plan at HT versus HN position (1.108 vs. 1.097. A change in head position from HN to HT with wedge pair plan resulted in a reduction of brainstem Dmax and Dmean. Lesser dose was observed in HN position for contralateral parotid. A difference of 0.9 Gy in the average Dmax to spinal cord was seen. The values of Dmean to mandible, oral cavity, ipsilateral and contralateral cochlea were higher in the HT position. A change in head position from HN to HT with IMRT plan resulted in a dose reduction in average Dmax to brainstem. The spinal cord Dmax increased at the HT position by 1.2 Gy. The dose to contralateral parotid and cochlea was comparable in both the positions. However, the Dmean to oral cavity was reduced at HT position. Whereas

Positive identity entry control system with geographically distributed portals and enrollment stations

International Nuclear Information System (INIS)

McIntire, J.M.

1985-01-01

A positive identity entry control system using distributed processing to allow reliable geographically separated portals and enrollment stations has been installed and is fully operational at a large area DOE site. Identity verification requires a credential, a memorized number and measurement of a physical characteristic of the user. Additionally, all portal activity is monitored by guards. The portal system is dual redundant such that no single point failure will shut down operations. Each portal site maintains its own subset of the master data base so off-site failure of the central data base manager or its communication links will not significantly affect local portal activity. The system is suitable for installations with large populations requiring access control at several remote sites scattered over a large area

TROSY of side-chain amides in large proteins

Science.gov (United States)

Liu, Aizhuo; Yao, Lishan; Li, Yue; Yan, Honggao

2012-01-01

By using the mixed solvent of 50% H2O/50% D2O and employing deuterium decoupling, TROSY experiments exclusively detect NMR signals from semideuterated isotopomers of carboxamide groups with high sensitivities for proteins with molecular weights up to 80 kDa. This isotopomer-selective strategy extends TROSY experiments from exclusively detecting backbone to both backbone and side-chain amides, particularly in large proteins. Because of differences in both TROSY effect and dynamics between 15N–HE{DZ} and 15N–HZ{DE} isotopomers of the same carboxamide, the 15N transverse magnetization of the latter relaxes significantly faster than that of the former, which provides a direct and reliable stereospecific distinction between the two configurations. The TROSY effects on the 15N–HE{DZ} isotopomers of side-chain amides are as significant as on backbone amides. PMID:17347000

Identification and positional distribution analysis of transcription factor binding sites for genes from the wheat fl-cDNA sequences.

Science.gov (United States)

Chen, Zhen-Yong; Guo, Xiao-Jiang; Chen, Zhong-Xu; Chen, Wei-Ying; Wang, Ji-Rui

2017-06-01

The binding sites of transcription factors (TFs) in upstream DNA regions are called transcription factor binding sites (TFBSs). TFBSs are important elements for regulating gene expression. To date, there have been few studies on the profiles of TFBSs in plants. In total, 4,873 sequences with 5' upstream regions from 8530 wheat fl-cDNA sequences were used to predict TFBSs. We found 4572 TFBSs for the MADS TF family, which was twice as many as for bHLH (1951), B3 (1951), HB superfamily (1914), ERF (1820), and AP2/ERF (1725) TFs, and was approximately four times higher than the remaining TFBS types. The percentage of TFBSs and TF members showed a distinct distribution in different tissues. Overall, the distribution of TFBSs in the upstream regions of wheat fl-cDNA sequences had significant difference. Meanwhile, high frequencies of some types of TFBSs were found in specific regions in the upstream sequences. Both TFs and fl-cDNA with TFBSs predicted in the same tissues exhibited specific distribution preferences for regulating gene expression. The tissue-specific analysis of TFs and fl-cDNA with TFBSs provides useful information for functional research, and can be used to identify relationships between tissue-specific TFs and fl-cDNA with TFBSs. Moreover, the positional distribution of TFBSs indicates that some types of wheat TFBS have different positional distribution preferences in the upstream regions of genes.

Theoretical role of adjunctive implant positional support in stress distribution of distal-extension mandibular removable partial dentures.

Science.gov (United States)

Xiao, Wei; Li, Zhiyong; Shen, Shiqian; Chen, Shaowu; Wang, Yining; Wang, Jiawei

2014-01-01

This preliminary study evaluated the adjunctive supporting role of diverse implant positions on stress distribution in a Class I removable partial denture (RPD) design. Nine three-dimensional finite element models were prepared to simulate mandibular RPD designs with three different loading conditions applied. Implant supported designs demonstrated lower stress value concentrations and mucosal displacement.

Source of Nitrous Oxide Emissions during the Cow Manure Composting Process as Revealed by Isotopomer Analysis of and amoA Abundance in Betaproteobacterial Ammonia-Oxidizing Bacteria▿ †

Science.gov (United States)

Maeda, Koki; Toyoda, Sakae; Shimojima, Ryosuke; Osada, Takashi; Hanajima, Dai; Morioka, Riki; Yoshida, Naohiro

2010-01-01

A molecular analysis of betaproteobacterial ammonia oxidizers and a N2O isotopomer analysis were conducted to study the sources of N2O emissions during the cow manure composting process. Much NO2−-N and NO3−-N and the Nitrosomonas europaea-like amoA gene were detected at the surface, especially at the top of the composting pile, suggesting that these ammonia-oxidizing bacteria (AOB) significantly contribute to the nitrification which occurs at the surface layer of compost piles. However, the 15N site preference within the asymmetric N2O molecule (SP = δ15Nα − δ15Nβ, where 15Nα and 15Nβ represent the 15N/14N ratios at the center and end sites of the nitrogen atoms, respectively) indicated that the source of N2O emissions just after the compost was turned originated mainly from the denitrification process. Based on these results, the reduction of accumulated NO2−-N or NO3−-N after turning was identified as the main source of N2O emissions. The site preference and bulk δ15N results also indicate that the rate of N2O reduction was relatively low, and an increased value for the site preference indicates that the nitrification which occurred mainly in the surface layer of the pile partially contributed to N2O emissions between the turnings. PMID:20048060

Method to measure the position offset of multiple light spots in a distributed aperture laser angle measurement system.

Science.gov (United States)

Jing, Xiaoli; Cheng, Haobo; Xu, Chunyun; Feng, Yunpeng

2017-02-20

In this paper, an accurate measurement method of multiple spots' position offsets on a four-quadrant detector is proposed for a distributed aperture laser angle measurement system (DALAMS). The theoretical model is put forward, as well as the corresponding calculation method. This method includes two steps. First, as the initial estimation, integral approximation is applied to fit the distributed spots' offset function; second, the Boltzmann function is employed to compensate for the estimation error to improve detection accuracy. The simulation results attest to the correctness and effectiveness of the proposed method, and tolerance synthesis analysis of DALAMS is conducted to determine the maximum uncertainties of manufacturing and installation. The maximum angle error is less than 0.08° in the prototype distributed measurement system, which shows the stability and robustness for prospective applications.

The influence of electrohydrodynamic flow on the distribution of chemical species in positive corona

Science.gov (United States)

Pontiga, Francisco; Yanallah, Khelifa; Bouazza, R.; Chen, Junhong

2015-09-01

A numerical simulation of positive corona discharge in air, including the effect of electrohydrodynamic (EHD) motion of the gas, has been carried out. Air flow is assumed to be confined between two parallel plates, and corona discharge is produced around a thin wire, midway between the plates. Therefore, fluid dynamics equations, including electrical forces, have been solved together with the continuity equation of each neutral species. The plasma chemical model included 24 chemical reactions and ten neutral species, in addition to electrons and positive ions. The results of the simulation have shown that the influence of EHD flow on the spatial distributions of the species is quite different depending on the species. Hence, reactive species like atomic oxygen and atomic nitrogen are confined to the vicinity of the wire, and they are weakly affected by the EHD gas motion. In contrast, nitrogen oxides and ozone are efficiently dragged outside the active region of the corona discharge by the EHD flow. This work was supported by the Spanish Government Agency ``Ministerio de Ciencia e Innovación'' under Contract No. FIS2011-25161.

Different percentages of false-positive results obtained using five methods for the calculation of reference change values based on simulated normal and ln-normal distributions of data

DEFF Research Database (Denmark)

Lund, Flemming; Petersen, Per Hyltoft; Fraser, Callum G

2016-01-01

a homeostatic set point that follows a normal (Gaussian) distribution. This set point (or baseline in steady-state) should be estimated from a set of previous samples, but, in practice, decisions based on reference change value are often based on only two consecutive results. The original reference change value......-positive results. The aim of this study was to investigate false-positive results using five different published methods for calculation of reference change value. METHODS: The five reference change value methods were examined using normally and ln-normally distributed simulated data. RESULTS: One method performed...... best in approaching the theoretical false-positive percentages on normally distributed data and another method performed best on ln-normally distributed data. The commonly used reference change value method based on two results (without use of estimated set point) performed worst both on normally...

Distributed Extended Kalman Filter for Position, Velocity, Time, Estimation in Satellite Navigation Receivers

Directory of Open Access Journals (Sweden)

O. Jakubov

2013-09-01

Full Text Available Common techniques for position-velocity-time estimation in satellite navigation, iterative least squares and the extended Kalman filter, involve matrix operations. The matrix inversion and inclusion of a matrix library pose requirements on a computational power and operating platform of the navigation processor. In this paper, we introduce a novel distributed algorithm suitable for implementation in simple parallel processing units each for a tracked satellite. Such a unit performs only scalar sum, subtraction, multiplication, and division. The algorithm can be efficiently implemented in hardware logic. Given the fast position-velocity-time estimator, frequent estimates can foster dynamic performance of a vector tracking receiver. The algorithm has been designed from a factor graph representing the extended Kalman filter by splitting vector nodes into scalar ones resulting in a cyclic graph with few iterations needed. Monte Carlo simulations have been conducted to investigate convergence and accuracy. Simulation case studies for a vector tracking architecture and experimental measurements with a real-time software receiver developed at CTU in Prague were conducted. The algorithm offers compromises in stability, accuracy, and complexity depending on the number of iterations. In scenarios with a large number of tracked satellites, it can outperform the traditional methods at low complexity.

Passive measurement-device-independent quantum key distribution with orbital angular momentum and pulse position modulation

Science.gov (United States)

Wang, Lian; Zhou, Yuan-yuan; Zhou, Xue-jun; Chen, Xiao

2018-03-01

Based on the orbital angular momentum and pulse position modulation, we present a novel passive measurement-device-independent quantum key distribution (MDI-QKD) scheme with the two-mode source. Combining with the tight bounds of the yield and error rate of single-photon pairs given in our paper, we conduct performance analysis on the scheme with heralded single-photon source. The numerical simulations show that the performance of our scheme is significantly superior to the traditional MDI-QKD in the error rate, key generation rate and secure transmission distance, since the application of orbital angular momentum and pulse position modulation can exclude the basis-dependent flaw and increase the information content for each single photon. Moreover, the performance is improved with the rise of the frame length. Therefore, our scheme, without intensity modulation, avoids the source side channels and enhances the key generation rate. It has greatly utility value in the MDI-QKD setups.

Comparative distribution of relaxin-3 inputs and calcium-binding protein-positive neurons in rat amygdala

Directory of Open Access Journals (Sweden)

Fabio N Santos

2016-04-01

Full Text Available The neural circuits involved in mediating complex behaviors are being rapidly elucidated using various newly developed and powerful anatomical and molecular techniques, providing insights into the neural basis for anxiety disorders, depression, addiction, and dysfunctional social behaviors. Many of these behaviors and associated physiological processes involve the activation of the amygdala in conjunction with cortical and hippocampal circuits. Ascending subcortical projections provide modulatory inputs to the extended amygdala and its related nodes (or ‘hubs’ within these key circuits. One such input arises from the nucleus incertus (NI in the tegmentum, which sends amino acid- and peptide-containing projections throughout the forebrain. Notably, a distinct population of GABAergic NI neurons expresses the highly-conserved neuropeptide, relaxin-3, and relaxin-3 signaling has been implicated in the modulation of reward/motivation and anxiety- and depressive-like behaviors in rodents via actions within the extended amygdala. Thus, a detailed description of the relaxin-3 innervation of the extended amygdala would provide an anatomical framework for an improved understanding of NI and relaxin-3 modulation of these and other specific amygdala-related functions. Therefore, in this study, we examined the distribution of NI projections and relaxin-3-positive elements (axons/fibers/terminals within the amygdala, relative to the distribution of neurons expressing the calcium-binding proteins, parvalbumin, calretinin and/or calbindin. Anterograde tracer injections into the NI revealed a topographic distribution of NI efferents within the amygdala that was near identical to the distribution of relaxin-3-immunoreactive fibers. Highest densities of anterogradely-labeled elements and relaxin-3-immunoreactive fibers were observed in the medial nucleus of the amygdala, medial divisions of the bed nucleus of the stria terminalis (BST and in the endopiriform

Beam position optimisation for IMRT

International Nuclear Information System (INIS)

Holloway, L.; Hoban, P.

2001-01-01

Full text: The introduction of IMRT has not generally resulted in the use of optimised beam positions because to find the global solution of the problem a time consuming stochastic optimisation method must be used. Although a deterministic method may not achieve the global minimum it should achieve a superior dose distribution compared to no optimisation. This study aimed to develop and test such a method. The beam optimisation method developed relies on an iterative process to achieve the desired number of beams from a large initial number of beams. The number of beams is reduced in a 'weeding-out' process based on the total fluence which each beam delivers. The process is gradual, with only three beams removed each time (following a small number of iterations), ensuring that the reduction in beams does not dramatically affect the fluence maps of those remaining. A comparison was made between the dose distributions achieved when the beams positions were optimised in this fashion and when the beams positions were evenly distributed. The method has been shown to work quite effectively and efficiently. The Figure shows a comparison in dose distribution with optimised and non optimised beam positions for 5 beams. It can be clearly seen that there is an improvement in the dose distribution delivered to the tumour and a reduction in the dose to the critical structure with beam position optimisation. A method for beam position optimisation for use in IMRT optimisations has been developed. This method although not necessarily achieving the global minimum in beam position still achieves quite a dramatic improvement compared with no beam position optimisation and is very efficiently achieved. Copyright (2001) Australasian College of Physical Scientists and Engineers in Medicine

Usual Dietary Energy Density Distribution Is Positively Associated with Excess Body Weight in Mexican Children.

Science.gov (United States)

Aburto, Tania C; Cantoral, Alejandra; Hernández-Barrera, Lucia; Carriquiry, Alicia L; Rivera, Juan A

2015-07-01

Studies suggest a positive association between dietary energy density (DED) and body weight in adults, but evidence in children is inconclusive. The objective of this study was to compare usual DED distributions of nonoverweight vs. overweight or obese (OW/O) Mexican children. The study used 24-h recall (24HR) data from 2367 children aged 5-11 y from the 2012 Mexican National Health and Nutrition Survey (ENSANUT 2012). Repeated 24HR measures were obtained in a random sample (∼10%) to estimate usual intake distributions by using the Iowa State University (PC-Side) method. Implausible dietary reports were identified. Multivariate linear regression models were used to evaluate the relation between DED and body mass index status and to compare results with and without PC-Side adjustment and restriction to plausible reporters. A total of 35.1% of the children in the sample were OW/O. The usual DED mean was ∼175 kcal/100 g in both the complete sample and the plausible reporters subsample. Regression models adjusted by PC-Side and for potential confounders showed higher DED in OW/O relative to nonoverweight children for both plausible reporters (9.7 kcal/100 g; n = 1452, P 0.10). A positive association between usual DED and OW/O was found in Mexican children. The association was stronger when only plausible reporters were considered. This suggests that there is a need for strategies to reduce energy density in the diet of Mexican children. © 2015 American Society for Nutrition.

Influence of the weighing bar position in vessel on measurement of cement’s particle size distribution by using the buoyancy weighing-bar method

Science.gov (United States)

Tambun, R.; Sihombing, R. O.; Simanjuntak, A.; Hanum, F.

2018-02-01

The buoyancy weighing-bar method is a new simple and cost-effective method to determine the particle size distribution both settling and floating particle. In this method, the density change in a suspension due to particle migration is measured by weighing buoyancy against a weighing-bar hung in the suspension, and then the particle size distribution is calculated using the length of the bar and the time-course change in the mass of the bar. The apparatus of this method consists of a weighing-bar and an analytical balance with a hook for under-floor weighing. The weighing bar is used to detect the density change in suspension. In this study we investigate the influences of position of weighing bar in vessel on settling particle size distribution measurements of cement by using the buoyancy weighing-bar method. The vessel used in this experiment is graduated cylinder with the diameter of 65 mm and the position of weighing bar is in center and off center of vessel. The diameter of weighing bar in this experiment is 10 mm, and the kerosene is used as a dispersion liquids. The results obtained show that the positions of weighing bar in vessel have no significant effect on determination the cement’s particle size distribution by using buoyancy weighing-bar method, and the results obtained are comparable to those measured by using settling balance method.

Patterns of Cellular Distribution with the Sentinel Node Positive for Breast Cancer

International Nuclear Information System (INIS)

Tsiapali, E.; Schmidt, M.M.; Dizon, D.; Steinhoff, M.; Gass, J.

2011-01-01

Background. Sentinel node biopsy (SNB) represents the standard of care in breast cancer axillary evaluation. Our study aims to characterize the patterns of malignant cell distribution within the sentinel nodes (SN). Methods. In a retrospective IRB-approved study, we examined the anatomic location of the nodal area with the highest radioactive signal or most intense blue staining (hot spot) and its distance from the metastatic foci. Results. 58 patients underwent SNB between January 2006 and February 2007. 12 patients with 19 positive SN were suitable for analysis. 4 (21%) metastases were located in the nodal hilum and 15 (79%) in the cortex. 6 (31%) metastases were found adjacent to the hotspot, and 9 (47%) within 4 mm of the hotspot. Conclusions. In our pilot series, SN metastases were within 4 mm of the hotspot in 78% of the cases. Pathologic analysis focused in that area may contribute to the more accurate identification of nodal metastases

Positive periodic solutions of periodic neutral Lotka-Volterra system with distributed delays

International Nuclear Information System (INIS)

Li Yongkun

2008-01-01

By using a fixed point theorem of strict-set-contraction, some criteria are established for the existence of positive periodic solutions of the following periodic neutral Lotka-Volterra system with distributed delays (dx i (t))/(dt) =x i (t)[a i (t)-Σ j=1 n b ij (t)∫ -T ij 0 K ij (θ)x j ( t+θ)dθ-Σ j=1 n c ij (t)∫ -T ij 0 K ij (θ) x j ' (t+θ)dθ],i=1,2,...,n, where a i ,b ij ,c ij element of C(R,R + ) (i, j = 1, 2, ..., n) are ω-periodic functions, T ij ,T ij element of (0,∞) (i, j = 1, 2, ..., n) and K ij ,K ij element of (R,R + ) satisfying ∫ -T ij 0 K ij (θ)dθ=1,∫ -T ij 0 K ij (θ)dθ=1, i, j = 1, 2, ..., n

Position-sensitive proportional counters using resistance-capacitance position encoding

International Nuclear Information System (INIS)

Kopp, M.K.; Borkowski, C.J.

1975-12-01

A new method was developed for encoding the position of individual photons, neutrons, or charged particles in proportional counters by using the distributed RC line characteristics of these counters. The signal processing is described and guidelines for the design and operation of these position sensitive proportional counters (PSPCs) are given. Using these guidelines, several prototypic PSPCs were constructed to improve the spatial resolution and shorten the signal processing time; for example, the intrinsic spatial uncertainty was reduced to 28 μ fwhm for alpha particles and 100 μ fwhm for low-energy x rays (2 to 6 keV). Also, the signal processing time was reduced to 0.6 μsec without seriously degrading the spatial resolution. These results have opened new fields of application of the RC position encoding method in imaging distributions of photons, charged particles, or neutrons in nuclear medicine, physics, and radiography

Comparison of the Distribution of Unsaturated Fatty Acids at the Sn-2 Position of Phospholipids and Triacylglycerols in Marine Fishes and Mammals.

Science.gov (United States)

Beppu, Fumiaki; Yasuda, Keiko; Okada, Ayako; Hirosaki, Yoshitsugu; Okazaki, Masako; Gotoh, Naohiro

2017-11-01

Highly unsaturated fatty acid (HUFA) binding at the sn-2 position of phospholipids (PL) becomes a resource for prostaglandin, leukotriene, resolvin, and protectin synthesis. Both triacylglycerol (TAG) and PL synthesis pathways in vivo are via phosphatidic acid; therefore, the distribution of fatty acid species at the sn-2 position must theoretically be the same for TAG and PL if rearrangement does not occur. However, it is known that little HUFA is located at the sn-2 position of TAG in marine mammals. Therefore, distribution of fatty acid species at the sn-2 position of TAG and PL was compared between marine fishes and mammals in this study. The composition of fatty acids binding at the sn-2 or sn-1,3 position of PL and TAG was analyzed via hydrolysis with enzymes and GC-FID. The results showed that 20:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3 were primarily located at the sn-1,3 positions of TAG in marine mammals. Comparison of the binding positions of HUFA and 16:0 in PL and TAG suggested the existence of Lands' cycle in marine fishes and mammals. In conclusion, both marine fishes and mammals condensed HUFA as a source of eicosanoid at the sn-2 position of PL. Furthermore, abundance ratios for 22:5n-3 or 22:6n-3 at the sn-2 position (sn-2 ratio) in TAG and PL (calculated by the equation: [abundance ratio at sn-2 position of TAG]/[abundance ratio at sn-2 position of PL]) was less than 0.35 in marine mammals; however, it was greater than 0.80 in marine fishes. These differences suggested that the HUFA consisted of 22 carbon atoms and had different roles in marine fishes and mammals.

Microbial Metabolism in Soil at Subzero Temperatures: Adaptation Mechanisms Revealed by Position-Specific 13C Labeling

Directory of Open Access Journals (Sweden)

Ezekiel K. Bore

2017-05-01

Full Text Available Although biogeochemical models designed to simulate carbon (C and nitrogen (N dynamics in high-latitude ecosystems incorporate extracellular parameters, molecular and biochemical adaptations of microorganisms to freezing remain unclear. This knowledge gap hampers estimations of the C balance and ecosystem feedback in high-latitude regions. To analyze microbial metabolism at subzero temperatures, soils were incubated with isotopomers of position-specifically 13C-labeled glucose at three temperatures: +5 (control, -5, and -20°C. 13C was quantified in CO2, bulk soil, microbial biomass, and dissolved organic carbon (DOC after 1, 3, and 10 days and also after 30 days for samples at -20°C. Compared to +5°C, CO2 decreased 3- and 10-fold at -5 and -20°C, respectively. High 13C recovery in CO2 from the C-1 position indicates dominance of the pentose phosphate pathway at +5°C. In contrast, increased oxidation of the C-4 position at subzero temperatures implies a switch to glycolysis. A threefold higher 13C recovery in microbial biomass at -5 than +5°C points to synthesis of intracellular compounds such as glycerol and ethanol in response to freezing. Less than 0.4% of 13C was recovered in DOC after 1 day, demonstrating complete glucose uptake by microorganisms even at -20°C. Consequently, we attribute the fivefold higher extracellular 13C in soil than in microbial biomass to secreted antifreeze compounds. This suggests that with decreasing temperature, intracellular antifreeze protection is complemented by extracellular mechanisms to avoid cellular damage by crystallizing water. The knowledge of sustained metabolism at subzero temperatures will not only be useful for modeling global C dynamics in ecosystems with periodically or permanently frozen soils, but will also be important in understanding and controlling the adaptive mechanisms of food spoilage organisms.

A Precision-Positioning Method for a High-Acceleration Low-Load Mechanism Based on Optimal Spatial and Temporal Distribution of Inertial Energy

Directory of Open Access Journals (Sweden)

Xin Chen

2015-09-01

Full Text Available High-speed and precision positioning are fundamental requirements for high-acceleration low-load mechanisms in integrated circuit (IC packaging equipment. In this paper, we derive the transient nonlinear dynamicresponse equations of high-acceleration mechanisms, which reveal that stiffness, frequency, damping, and driving frequency are the primary factors. Therefore, we propose a new structural optimization and velocity-planning method for the precision positioning of a high-acceleration mechanism based on optimal spatial and temporal distribution of inertial energy. For structural optimization, we first reviewed the commonly flexible multibody dynamic optimization using equivalent static loads method (ESLM, and then we selected the modified ESLM for optimal spatial distribution of inertial energy; hence, not only the stiffness but also the inertia and frequency of the real modal shapes are considered. For velocity planning, we developed a new velocity-planning method based on nonlinear dynamic-response optimization with varying motion conditions. Our method was verified on a high-acceleration die bonder. The amplitude of residual vibration could be decreased by more than 20% via structural optimization and the positioning time could be reduced by more than 40% via asymmetric variable velocity planning. This method provides an effective theoretical support for the precision positioning of high-acceleration low-load mechanisms.

Position Error Covariance Matrix Validation and Correction

Science.gov (United States)

Frisbee, Joe, Jr.

2016-01-01

In order to calculate operationally accurate collision probabilities, the position error covariance matrices predicted at times of closest approach must be sufficiently accurate representations of the position uncertainties. This presentation will discuss why the Gaussian distribution is a reasonable expectation for the position uncertainty and how this assumed distribution type is used in the validation and correction of position error covariance matrices.

Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators

Directory of Open Access Journals (Sweden)

C. S. Edmonds

2014-05-01

Full Text Available 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.

Distribution of anti-HAV IgM positivity according to age and months of a year in Van region,Turkey

Directory of Open Access Journals (Sweden)

Mehmet Parlak

2012-09-01

Full Text Available Objectives: In this study we investigated the anti-HAVIgM positivity rates and their distribution according to ageand season of a year in Van region of Turkey.Materials and methods: During five-year period between2006-2010, the presence of anti-HAV IgM weredetermined in the serum samples sent to our laboratorythat have prediagnosis of hepatitis A by ELISA test, usingAxSYM (Abbott Diagnostics, Germany and i2000SR Architect(Abbott Diagnostics, Germany analyzers. For statisticalanalyze of Anti-HAV IgM positivity rates, patients’age and gender and time of year when specimen wasobtain were compared.Results: The presence of anti-HAV IgM was investigatedin a total of 8851 patients, including 5303 (60% childrenand 3548 (40% adults. Anti-HAV IgM in children and adultpatients were determined as 9.8% and 2.6%, respectively,and this difference was found statistically significant (p<0.01. Anti-HAV IgM positivity rate began to rise in August,reached the highest level in November-Decemberand decreased to the initial level in January. The highestfrequency detected during the November-December periodwas statistically significantly higher than rates foundduring other months.Conclusions: The prevalence of Hepatitis A was found tobe similar with previous studies performed in our country.The prevalence of disease was significantly increased especiallybetween November and December.Key words: Anti-HAV IgM, seasonal distribution, seroprevalence,age

Performance of Distributed CFAR Processors in Pearson Distributed Clutter

Directory of Open Access Journals (Sweden)

Messali Zoubeida

2007-01-01

Full Text Available This paper deals with the distributed constant false alarm rate (CFAR radar detection of targets embedded in heavy-tailed Pearson distributed clutter. In particular, we extend the results obtained for the cell averaging (CA, order statistics (OS, and censored mean level CMLD CFAR processors operating in positive alpha-stable (P&S random variables to more general situations, specifically to the presence of interfering targets and distributed CFAR detectors. The receiver operating characteristics of the greatest of (GO and the smallest of (SO CFAR processors are also determined. The performance characteristics of distributed systems are presented and compared in both homogeneous and in presence of interfering targets. We demonstrate, via simulation results, that the distributed systems when the clutter is modelled as positive alpha-stable distribution offer robustness properties against multiple target situations especially when using the "OR" fusion rule.

Performance of Distributed CFAR Processors in Pearson Distributed Clutter

Directory of Open Access Journals (Sweden)

Faouzi Soltani

2007-01-01

Full Text Available This paper deals with the distributed constant false alarm rate (CFAR radar detection of targets embedded in heavy-tailed Pearson distributed clutter. In particular, we extend the results obtained for the cell averaging (CA, order statistics (OS, and censored mean level CMLD CFAR processors operating in positive alpha-stable (P&S random variables to more general situations, specifically to the presence of interfering targets and distributed CFAR detectors. The receiver operating characteristics of the greatest of (GO and the smallest of (SO CFAR processors are also determined. The performance characteristics of distributed systems are presented and compared in both homogeneous and in presence of interfering targets. We demonstrate, via simulation results, that the distributed systems when the clutter is modelled as positive alpha-stable distribution offer robustness properties against multiple target situations especially when using the “OR” fusion rule.

Laterally resolved ion-distribution functions at the substrate position during magnetron sputtering of indium-tin oxide films

International Nuclear Information System (INIS)

Plagemann, A.; Ellmer, K.; Wiesemann, K.

2007-01-01

During the magnetron sputtering from an indium-tin oxide (ITO) target (76 mm diameter) we measured the ion-distribution functions (IDFs) of energetic ions (argon, indium, and oxygen ions) at the substrate surface using a combination of a quadrupole mass spectrometer and an electrostatic energy analyzer. We obtained the IDFs for argon sputtering pressures in the range from 0.08 to 2 Pa and for dc as well as rf (13.56 MHz) plasma excitation with powers from 10 to 100 W. The IDF measurements were performed both over the target center at a target-to-substrate distance of 65 mm and at different positions along the target radius in order to scan the erosion track of the target. The mean kinetic energies of argon ions calculated from the IDFs in the dc plasma decreased from about 30 to 15 eV, when the argon pressure increased from 0.08 to 2 Pa, which is caused by a decrease of the electron temperature also by a factor of 2. Indium atoms exhibit higher mean energies due to their additional energy from the sputtering process. The total metal ion flux turns out to be proportional to the discharge power and the pressure, the latter dependence being due to Penning ionization of the metal atoms (In and Sn). From the scans across the target surface the lateral distributions of metal, oxygen, and argon ions were derived. In the dc discharge the position of the erosion track is reproduced by increased ion intensities, while it is not the case for the rf excited plasma. The lateral variations of the observed species do not influence the lateral resistivity distributions of the deposited ITO films

Descriptive study of electromagnetic wave distribution for various seating positions: using digital textbooks.

Science.gov (United States)

Seomun, GyeongAe; Kim, YoungHwan; Lee, Jung-Ah; Jeong, KwangHoon; Park, Seon-A; Kim, Miran; Noh, Wonjung

2014-04-01

To better understand environmental electromagnetic wave exposure during the use of digital textbooks by elementary school students, we measured numeric values of the electromagnetic fields produced by tablet personal computers (TPCs). Specifically, we examined the distribution of the electromagnetic waves for various students' seating positions in an elementary school that uses digital textbooks. Electric and magnetic fields from TPCs were measured using the HI-3603 Visual Display Terminal/ Very Low Frequency (VDT/VLF) radiation measurement system. Electromagnetic field values from TPCs measured at a student's seat and at a teacher's computer were deemed not harmful to health. However, electromagnetic field values varied based on the distance between students, other electronic devices such as a desktop computers, and student posture while using a TPC. Based on these results, it is necessary to guide students to observe proper posture and to arrange seats at an appropriate distance in the classroom.

Natural isotope correction of MS/MS measurements for metabolomics and (13)C fluxomics.

Science.gov (United States)

Niedenführ, Sebastian; ten Pierick, Angela; van Dam, Patricia T N; Suarez-Mendez, Camilo A; Nöh, Katharina; Wahl, S Aljoscha

2016-05-01

Fluxomics and metabolomics are crucial tools for metabolic engineering and biomedical analysis to determine the in vivo cellular state. Especially, the application of (13)C isotopes allows comprehensive insights into the functional operation of cellular metabolism. Compared to single MS, tandem mass spectrometry (MS/MS) provides more detailed and accurate measurements of the metabolite enrichment patterns (tandem mass isotopomers), increasing the accuracy of metabolite concentration measurements and metabolic flux estimation. MS-type data from isotope labeling experiments is biased by naturally occurring stable isotopes (C, H, N, O, etc.). In particular, GC-MS(/MS) requires derivatization for the usually non-volatile intracellular metabolites introducing additional natural isotopes leading to measurements that do not directly represent the carbon labeling distribution. To make full use of LC- and GC-MS/MS mass isotopomer measurements, the influence of natural isotopes has to be eliminated (corrected). Our correction approach is analyzed for the two most common applications; (13)C fluxomics and isotope dilution mass spectrometry (IDMS) based metabolomics. Natural isotopes can have an impact on the calculated flux distribution which strongly depends on the substrate labeling and the actual flux distribution. Second, we show that in IDMS based metabolomics natural isotopes lead to underestimated concentrations that can and should be corrected with a nonlinear calibration. Our simulations indicate that the correction for natural abundance in isotope based fluxomics and quantitative metabolomics is essential for correct data interpretation. © 2015 Wiley Periodicals, Inc.

Influence of second kind collisions on the electron distribution function in the positive column of low pressure nitrogen discharge

International Nuclear Information System (INIS)

Rohlena, K.; Ruzicka, T.

1979-01-01

A numerical solution of the Boltzmann equation for the electron gas in the positive column of a DC discharge in nitrogen is presented. The Boltzmann equation was solved with the inclusion of the second-kind (superelastic) collisions proceeding from the first six excited vibrational levels of molecular nitrogen. The vibrational level population is supposed to follow the Boltzmann distribution for the given vibrational temperature Tsub(v), with a possible deviation of the ground level, which can be overpopulated in the given ratio γ. Apart from the electron distribution functions, which were gained for various values of E/p 0 , Tsub(v) and γ, the values of some production frequencies and kinetic coefficients are presented in form of tables and plots. It is found that the electron distribution (and also the corresponding production rates) only above a certain energy limit depends on Tsub(v) and γ through the normalization constant. (author)

Distribution of coagulase-positive staphylococci in humans and dogs

OpenAIRE

Jurate Sleiniute; Jurate Siugzdaite

2015-01-01

Staphylococci form part of the normal flora of humans and a wide variety of animals. Some staphylococcal species also cause infections for human and household pets. The aim of this study was to investigate the prevalence of coagulase-positive staphylococci in humans and dogs within a common household. Coagulase-positive staphylococci could not be identified phenotypically in all cases. Molecular methods were used for the correct identification of pathogenic staphylococci. The prevalence of St...

Application of solid-state tritium NMR in determining the bioactive conformation of paclitaxel

International Nuclear Information System (INIS)

Lin, T.

2012-01-01

The determination of the conformation of small molecule bound to its biological target would facilitate people to design improved drugs. This determination can be difficult due to technical limitations, as exemplified by the long standing debate on the microtubule-binding conformation of a natural anticancer drug - paclitaxel. Previous studies using X-ray crystallography and solution-state NMR failed to furnish direct information on the expected conformation. Solid-state NMR may help in this task by providing precise interatomic distances, and the selective labeling on different sites with tritium atoms enables accurate measurement of long-range distances (up to 14.4 Angstroms) owing to the high gyromagnetic ratio of this nucleus, without any structural modification of the molecule. So our project aiming at illustrating the bioactive conformation of paclitaxel consists the syntheses of 6 different paclitaxel isotopomers bearing a pair of tritium at specified positions, flowing by the preparations of corresponding microtubule-labeled paclitaxel complexes. The solid-state tritium NMR analyses of these complexes would provide key distances for determining the expected conformation. Up to now, 2 paclitaxel isotopomers have been prepared from labelling the di-brominated paclitaxel precursor and from coupling the tritiated taxane rings and the tritiated side chains, respectively. The synthetic strategy allowed us to realize the syntheses in generally high yield and good stereoselectivity. Different tritiation methods have been used, from which an isotopic enrichment of higher than 92% was obtained. The syntheses of other 4 isotopomers, together with the microtubule complexes are currently underway in our lab. (author) [fr

Distribution of positive ion species above a diffuse midnight aurora

International Nuclear Information System (INIS)

Moore, T.E.

1978-01-01

The origin of the hot plasma in the Earth's magnetosphere is still open to investigation. Mass composition is an indicator of source region, while the distribution functions bear the signatures of transport and energization processes. Only ions identified as H + and He ++ were detected, and the He ++ was statistically marginal. Coincident magnetic storms are likely to play a crucial role in populating the magnetosphere with energized ionospheric ions. The measured proton distribution was nearly isotropic over downcoming pitch angles at all energies and showed a depleted atmospheric source cone. The high-altitude proton energy distribution had a best fit temperature of 4.5 keV and a number density of 0.17 cm- 3 , corresponding to a peak intensity just over 10 5 cm -2 s -1 sr -1 keV -1 . Altitudinal variations are consistent with the theory of charge exchange of a time-steady incident proton population. Simultaneous electron measurements can be interpreted in terms of an incident electron distribution that is also thermal wih a similar number density but a temperature of 2.5 keV. Taken together, the ion and electron data are consistent with the model of diffuse auroras in which plasma convecting in from the magnetospheric tail precipitates due to strong pitch angle diffusion on auroral field lines linking the near Earth plasma sheet

OPTIMIZATION OF THE POSITION OF THE LOCAL DISTRIBUTION CENTRE OF THE REGIONAL POST LOGISTICS NETWORK

Directory of Open Access Journals (Sweden)

Paweł DROŹDZIEL

2017-09-01

Full Text Available The phenomenon of the present postal services is the fact that, customers expect the lowest price while maintaining the availability, security and on time delivery of mail items. We can find that, the costs associated with transport of the postal substrate is one of the most important factors affecting the total cost of the postal services. These transport costs depend on various factors such as the investment in vehicles purchase, operational costs of the postal vehicles (costs of maintenance, repairs, fuel costs of the vehicle, etc. labour costs of the drivers and so on. For this reason, it is important to find such an operational - organizational solutions that can reduce the costs associated with the transportation of postal shipments, resulting in reducing the total cost of postal services. One option to do this is to minimize the length of postal transportation routes. This article presents the approach based on the application of graph theory to optimize existing connections of postal logistics network. Published results is oriented to revaluate existing position of local centre and find a location for the new local distribution centre potentially. New location of local distribution centre can to optimize (minimize the total transport costs of the local postal transportation network in area of the Lublin Province.

Positional information generated by spatially distributed signaling cascades.

Directory of Open Access Journals (Sweden)

Javier Muñoz-García

2009-03-01

Full Text Available The temporal and stationary behavior of protein modification cascades has been extensively studied, yet little is known about the spatial aspects of signal propagation. We have previously shown that the spatial separation of opposing enzymes, such as a kinase and a phosphatase, creates signaling activity gradients. Here we show under what conditions signals stall in the space or robustly propagate through spatially distributed signaling cascades. Robust signal propagation results in activity gradients with long plateaus, which abruptly decay at successive spatial locations. We derive an approximate analytical solution that relates the maximal amplitude and propagation length of each activation profile with the cascade level, protein diffusivity, and the ratio of the opposing enzyme activities. The control of the spatial signal propagation appears to be very different from the control of transient temporal responses for spatially homogenous cascades. For spatially distributed cascades where activating and deactivating enzymes operate far from saturation, the ratio of the opposing enzyme activities is shown to be a key parameter controlling signal propagation. The signaling gradients characteristic for robust signal propagation exemplify a pattern formation mechanism that generates precise spatial guidance for multiple cellular processes and conveys information about the cell size to the nucleus.

Effect of body mass distribution on the ontogeny of positional behaviors in non-human primates: Longitudinal follow-up of infant captive olive baboons (Papio anubis).

Science.gov (United States)

Druelle, François; Aerts, Peter; Berillon, Gilles

2016-11-01

The diversity of primates' positional capabilities is unique among mammals. Indeed, they exhibit a daily repertoire composed of various locomotor and postural modes that may be linked to their particular morphological pattern. Because ontogeny undergoes parallel behavioral and morphological modifications, it may be useful to investigate the biomechanical consequences of the changing body shape. We, therefore, collected accurate quantitative and longitudinal data on positional behaviors, body mass distribution patterns, activities, and environment on a sample of six infant olive baboons, Papio anubis. These baboons are kept at the Primatology Station of the CNRS, France, where they live within the same social group. Individual behaviors were quantified using the focal sampling method. The body mass distribution was estimated according to a geometric model based on direct external measurements. Multivariate analysis enabled us to analyze the interactions between the data. Our results show that body mass distribution changes together with the ontogenetic changes in positional behaviors. At an early age, individuals have distally heavy segment masses in the limbs and an important fraction of the behavioral repertoire involves efficient grasping abilities. At the end of infancy, the same individuals have relatively more mass in proximal segments of the limbs and the proportion of quadrupedal walking is significantly higher while other climbing and suspensory behaviors decreased substantially. The present study experimentally confirms the association between body mass distribution and the positional repertoire of primates. These relationships, when interpreted in the context of basic biomechanical concepts, may improve our understanding of primate locomotion. We discuss further the implications of these functional relationships when modeling the evolutionary pathway of primates. Am. J. Primatol. 78:1201-1221, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley

Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

International Nuclear Information System (INIS)

Al-Hawat, Sh; Naddaf, M

2005-01-01

The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j d = 4.45 mA cm -2 and normalized electric field strength E/p = 1.88 V cm -1 Torr -1

Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

Science.gov (United States)

Al-Hawat, Sh; Naddaf, M.

2005-04-01

The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density jd = 4.45 mA cm-2 and normalized electric field strength E/p = 1.88 V cm-1 Torr-1.

Distributed estimation of sensors position in underwater wireless sensor network

Science.gov (United States)

Zandi, Rahman; Kamarei, Mahmoud; Amiri, Hadi

2016-05-01

In this paper, a localisation method for determining the position of fixed sensor nodes in an underwater wireless sensor network (UWSN) is introduced. In this simple and range-free scheme, the node localisation is achieved by utilising an autonomous underwater vehicle (AUV) that transverses through the network deployment area, and that periodically emits a message block via four directional acoustic beams. A message block contains the actual known AUV position as well as a directional dependent marker that allows a node to identify the respective transmit beam. The beams form a fixed angle with the AUV body. If a node passively receives message blocks, it could calculate the arithmetic mean of the coordinates existing in each messages sequence, to find coordinates at two different time instants via two different successive beams. The node position can be derived from the two computed positions of the AUV. The major advantage of the proposed localisation algorithm is that it is silent, which leads to energy efficiency for sensor nodes. The proposed method does not require any synchronisation among the nodes owing to being silent. Simulation results, using MATLAB, demonstrated that the proposed method had better performance than other similar AUV-based localisation methods in terms of the rates of well-localised sensor nodes and positional root mean square error.

Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

Energy Technology Data Exchange (ETDEWEB)

Al-Hawat, Sh; Naddaf, M [Physics Department, Atomic Energy Commission, PO Box 6091, Damascus (Syrian Arab Republic)

2005-04-21

The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j{sub d} = 4.45 mA cm{sup -2} and normalized electric field strength E/p = 1.88 V cm{sup -1} Torr{sup -1}.

The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry.

Science.gov (United States)

Westley, Marian B; Popp, Brian N; Rust, Terri M

2007-01-01

Two alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the delta15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30 per thousand. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 +/- 1.4 per thousand for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 +/- 2.2 per thousand for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 +/- 2.2 per thousand for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright 2007 John Wiley & Sons, Ltd.

Deciphering the "chemical" nature of the exotic isotopes of hydrogen by the MC-QTAIM analysis: the positively charged muon and the muonic helium as new members of the periodic table.

Science.gov (United States)

Goli, Mohammad; Shahbazian, Shant

2014-04-14

This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic helium, i.e., the negatively charged muon plus helium nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions. Accordingly, the "atoms in molecules" analysis performed on various asymmetric exotic isotopomers of the hydrogen molecule, recently detected experimentally [Science, 2011, 331, 448], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atoms. Various derived properties of atomic basins containing the muonic helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization. However, with some tolerance, they may also be categorized as hydrogen basins though with a smaller electronegativity. All in all, the present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, which are difficult to elucidate by experimental and/or alternative theoretical schemes.

Tunable Far Infrared Studies in Support of Stratospheric Measurements

Science.gov (United States)

Chance, Kelly V.; Park, K.; Nolt, I. G.; Evenson, K. M.

2001-01-01

This report summarizes research done under NASA Grant NAG5-4653. The research performed under this grant has been a collaboration between institutions including the Smithsonian Astrophysical Observatory, the National Institute of Standards and Technology, the University of Oregon, and the NASA Langley Research Center. The program has included fully line-resolved measurements of submillimeter and far infrared spectroscopic line parameters (pressure broadening coefficients and their temperature dependences, and line positions) for the analysis of field measurements of stratospheric constituents, far infrared database improvements, and studies for improved satellite measurements of the Earth's atmosphere. This research program is designed to enable the full utilization of spectra obtained in far infrared/submillimeter field measurements, such as FIRS-2, FILOS, IBEX, SLS, EosMLS, and proposed European Space Agency measurements of OH (e.g., PIRAMHYD and SFINX) for the retrieval of accurate stratospheric altitude profiles of key trace gases involved in ozone layer photochemistry. For the analysis of the spectra obtained in the stratosphere from far infrared measurements it is necessary to have accurate values of the molecular parameters (line positions, strengths, and pressure broadening coefficients) for the measured molecules and for possible interfering species. Knowledge of line positions is in increasingly good shape, with some notable exceptions. The increase in position information includes research that has been performed in the present program of research on HO2, H2O, H2O2, O3, HCl, HF, HBr, HI, CO, OH, and ClO. Examples where further line position studies are necessary include hot band and minor isotopomer lines of some of the major trace species (H2O, O3) and normal lines of some triatomic and larger molecules (NO2). Knowledge of strengths is in generally good shape, since most of the lines are from electric dipole transitions whose intensities are well

Performance of Distributed CFAR Processors in Pearson Distributed Clutter

OpenAIRE

Messali Zoubeida; Soltani Faouzi

2007-01-01

This paper deals with the distributed constant false alarm rate (CFAR) radar detection of targets embedded in heavy-tailed Pearson distributed clutter. In particular, we extend the results obtained for the cell averaging (CA), order statistics (OS), and censored mean level CMLD CFAR processors operating in positive alpha-stable (P&S) random variables to more general situations, specifically to the presence of interfering targets and distributed CFAR detectors. The receiver operating ...

Unifying distribution functions: some lesser known distributions.

Science.gov (United States)

Moya-Cessa, J R; Moya-Cessa, H; Berriel-Valdos, L R; Aguilar-Loreto, O; Barberis-Blostein, P

2008-08-01

We show that there is a way to unify distribution functions that describe simultaneously a classical signal in space and (spatial) frequency and position and momentum for a quantum system. Probably the most well known of them is the Wigner distribution function. We show how to unify functions of the Cohen class, Rihaczek's complex energy function, and Husimi and Glauber-Sudarshan distribution functions. We do this by showing how they may be obtained from ordered forms of creation and annihilation operators and by obtaining them in terms of expectation values in different eigenbases.

Oscillation for equations with positive and negative coefficients and with distributed delay I: General results

Directory of Open Access Journals (Sweden)

Leonid Berezansky

2003-02-01

Full Text Available We study a scalar delay differential equation with a bounded distributed delay, $$ dot{x}(t+ int_{h(t}^t x(s,d_s R(t,s - int_{g(t}^t x(s,d_s T(t,s=0, $$ where $R(t,s$, $T(t,s$ are nonnegative nondecreasing in $s$ for any $t$, $$ R(t,h(t=T(t,g(t=0, quad R(t,s geq T(t,s. $$ We establish a connection between non-oscillation of this differential equation and the corresponding differential inequalities, and between positiveness of the fundamental function and the existence of a nonnegative solution for a nonlinear integral inequality that constructed explicitly. We also present comparison theorems, and explicit non-oscillation and oscillation results. In a separate publication (part II, we will consider applications of this theory to differential equations with several concentrated delays, integrodifferential, and mixed equations.

Spatial distribution of prominin-1 (CD133-positive cells within germinative zones of the vertebrate brain.

Directory of Open Access Journals (Sweden)

József Jászai

Full Text Available In mammals, embryonic neural progenitors as well as adult neural stem cells can be prospectively isolated based on the cell surface expression of prominin-1 (CD133, a plasma membrane glycoprotein. In contrast, characterization of neural progenitors in non-mammalian vertebrates endowed with significant constitutive neurogenesis and inherent self-repair ability is hampered by the lack of suitable cell surface markers. Here, we have investigated whether prominin-1-orthologues of the major non-mammalian vertebrate model organisms show any degree of conservation as for their association with neurogenic geminative zones within the central nervous system (CNS as they do in mammals or associated with activated neural progenitors during provoked neurogenesis in the regenerating CNS.We have recently identified prominin-1 orthologues from zebrafish, axolotl and chicken. The spatial distribution of prominin-1-positive cells--in comparison to those of mice--was mapped in the intact brain in these organisms by non-radioactive in situ hybridization combined with detection of proliferating neural progenitors, marked either by proliferating cell nuclear antigen or 5-bromo-deoxyuridine. Furthermore, distribution of prominin-1 transcripts was investigated in the regenerating spinal cord of injured axolotl.Remarkably, a conserved association of prominin-1 with germinative zones of the CNS was uncovered as manifested in a significant co-localization with cell proliferation markers during normal constitutive neurogenesis in all species investigated. Moreover, an enhanced expression of prominin-1 became evident associated with provoked, compensatory neurogenesis during the epimorphic regeneration of the axolotl spinal cord. Interestingly, significant prominin-1-expressing cell populations were also detected at distinct extraventricular (parenchymal locations in the CNS of all vertebrate species being suggestive of further, non-neurogenic neural function

The burden, distribution and risk factors for cervical oncogenic human papilloma virus infection in HIV positive Nigerian women.

Science.gov (United States)

Ezechi, Oliver Chukwujekwu; Ostergren, Per Olof; Nwaokorie, Francisca Obiageri; Ujah, Innocent Achaya Otobo; Odberg Pettersson, Karen

2014-01-15

The expected reduction in cervical cancer incidence as a result of increased access to antiretroviral therapy is yet to be seen. In this study we investigated the effect of HIV infection and treatment on high-risk (hr) human papilloma virus (HPV) prevalence and distribution. Cervical cells from 515 (220 HIV positive and 295 HIV negative) women, recruited during community cervical cancer screening programme in states of Ogun and Lagos and at the cervical cancer screen clinic, Nigerian Institute of Medical Research Lagos were evaluated for the presence of 13 hr HPV genotypes by polymerase chain reaction based assay. The prevalence of high-risk HPV was 19.6% in the studied population. HPV 16 (3.9%), 35 (3.5%), 58 (3.3%) and 31 (3.3%) were the most common hr HPV infections detected. We observed that the prevalence of hr HPV was higher in HIV positives (24.5%) than 15.9% in HIV negative women (OR = 1.7; 95% CI: 1.1-2.7). A multivariate logistic regression analysis showed a lower hr HPV prevalence in HIV positive women on antiretroviral drugs (OR = 0.4; 95% CI: 0.3-0.5) and with CD4 count of 500 and above (OR = 0.7; 95% CI: 0.5-0.8). A higher prevalence of hr HPV was also noted in HIV positive women with CD4 count prevalence of HPV 16 and 35 in HIV positive women than in HIV negative women. The use of antiretroviral drugs was found to be associated with a lower prevalence of hr HPV infection, compared to those not on treatment. This study raises important issues that should be further investigated to enable the development of robust cervical cancer prevention and control strategies for women in our setting.

The effect of on-line position correction on the dose distribution in focal radiotherapy for bladder cancer

Energy Technology Data Exchange (ETDEWEB)

Rooijen, Dominique C van; Kamer, Jeroen B van de; Pool, René; Hulshof, Maarten CCM; Koning, Caro CE; Bel, Arjan [Department of Radiation Oncology, Academic Medical Center, Amsterdam (Netherlands)

2009-09-24

The purpose of this study was to determine the dosimetric effect of on-line position correction for bladder tumor irradiation and to find methods to predict and handle this effect. For 25 patients with unifocal bladder cancer intensity modulated radiotherapy (IMRT) with 5 beams was planned. The requirement for each plan was that 99% of the target volume received 95% of the prescribed dose. Tumor displacements from -2.0 cm to 2.0 cm in each dimension were simulated, using 0.5 cm increments, resulting in 729 simulations per patient. We assumed that on-line correction for the tumor was applied perfectly. We determined the correlation between the change in D{sub 99%} and the change in path length, which is defined here as the distance from the skin to the isocenter for each beam. In addition the margin needed to avoid underdosage was determined and the probability that an underdosage occurs in a real treatment was calculated. Adjustments for tumor displacement with perfect on-line position correction resulted in an altered dose distribution. The altered fraction dose to the target varied from 91.9% to 100.4% of the prescribed dose. The mean D{sub 99%} (± SD) was 95.8% ± 1.0%. There was a modest linear correlation between the difference in D{sub 99%} and the change in path length of the beams after correction (R{sup 2} = 0.590). The median probability that a systematic underdosage occurs in a real treatment was 0.23% (range: 0 - 24.5%). A margin of 2 mm reduced that probability to < 0.001% in all patients. On-line position correction does result in an altered target coverage, due to changes in average path length after position correction. An extra margin can be added to prevent underdosage.

The effect of on-line position correction on the dose distribution in focal radiotherapy for bladder cancer

Directory of Open Access Journals (Sweden)

Koning Caro CE

2009-09-01

Full Text Available Abstract Background The purpose of this study was to determine the dosimetric effect of on-line position correction for bladder tumor irradiation and to find methods to predict and handle this effect. Methods For 25 patients with unifocal bladder cancer intensity modulated radiotherapy (IMRT with 5 beams was planned. The requirement for each plan was that 99% of the target volume received 95% of the prescribed dose. Tumor displacements from -2.0 cm to 2.0 cm in each dimension were simulated, using 0.5 cm increments, resulting in 729 simulations per patient. We assumed that on-line correction for the tumor was applied perfectly. We determined the correlation between the change in D99% and the change in path length, which is defined here as the distance from the skin to the isocenter for each beam. In addition the margin needed to avoid underdosage was determined and the probability that an underdosage occurs in a real treatment was calculated. Results Adjustments for tumor displacement with perfect on-line position correction resulted in an altered dose distribution. The altered fraction dose to the target varied from 91.9% to 100.4% of the prescribed dose. The mean D99% (± SD was 95.8% ± 1.0%. There was a modest linear correlation between the difference in D99% and the change in path length of the beams after correction (R2 = 0.590. The median probability that a systematic underdosage occurs in a real treatment was 0.23% (range: 0 - 24.5%. A margin of 2 mm reduced that probability to Conclusion On-line position correction does result in an altered target coverage, due to changes in average path length after position correction. An extra margin can be added to prevent underdosage.

The effect of on-line position correction on the dose distribution in focal radiotherapy for bladder cancer

Science.gov (United States)

van Rooijen, Dominique C; van de Kamer, Jeroen B; Pool, René; Hulshof, Maarten CCM; Koning, Caro CE; Bel, Arjan

2009-01-01

Background The purpose of this study was to determine the dosimetric effect of on-line position correction for bladder tumor irradiation and to find methods to predict and handle this effect. Methods For 25 patients with unifocal bladder cancer intensity modulated radiotherapy (IMRT) with 5 beams was planned. The requirement for each plan was that 99% of the target volume received 95% of the prescribed dose. Tumor displacements from -2.0 cm to 2.0 cm in each dimension were simulated, using 0.5 cm increments, resulting in 729 simulations per patient. We assumed that on-line correction for the tumor was applied perfectly. We determined the correlation between the change in D99% and the change in path length, which is defined here as the distance from the skin to the isocenter for each beam. In addition the margin needed to avoid underdosage was determined and the probability that an underdosage occurs in a real treatment was calculated. Results Adjustments for tumor displacement with perfect on-line position correction resulted in an altered dose distribution. The altered fraction dose to the target varied from 91.9% to 100.4% of the prescribed dose. The mean D99% (± SD) was 95.8% ± 1.0%. There was a modest linear correlation between the difference in D99% and the change in path length of the beams after correction (R2 = 0.590). The median probability that a systematic underdosage occurs in a real treatment was 0.23% (range: 0 - 24.5%). A margin of 2 mm reduced that probability to < 0.001% in all patients. Conclusion On-line position correction does result in an altered target coverage, due to changes in average path length after position correction. An extra margin can be added to prevent underdosage. PMID:19775479

The effect of on-line position correction on the dose distribution in focal radiotherapy for bladder cancer

International Nuclear Information System (INIS)

Rooijen, Dominique C van; Kamer, Jeroen B van de; Pool, René; Hulshof, Maarten CCM; Koning, Caro CE; Bel, Arjan

2009-01-01

The purpose of this study was to determine the dosimetric effect of on-line position correction for bladder tumor irradiation and to find methods to predict and handle this effect. For 25 patients with unifocal bladder cancer intensity modulated radiotherapy (IMRT) with 5 beams was planned. The requirement for each plan was that 99% of the target volume received 95% of the prescribed dose. Tumor displacements from -2.0 cm to 2.0 cm in each dimension were simulated, using 0.5 cm increments, resulting in 729 simulations per patient. We assumed that on-line correction for the tumor was applied perfectly. We determined the correlation between the change in D 99% and the change in path length, which is defined here as the distance from the skin to the isocenter for each beam. In addition the margin needed to avoid underdosage was determined and the probability that an underdosage occurs in a real treatment was calculated. Adjustments for tumor displacement with perfect on-line position correction resulted in an altered dose distribution. The altered fraction dose to the target varied from 91.9% to 100.4% of the prescribed dose. The mean D 99% (± SD) was 95.8% ± 1.0%. There was a modest linear correlation between the difference in D 99% and the change in path length of the beams after correction (R 2 = 0.590). The median probability that a systematic underdosage occurs in a real treatment was 0.23% (range: 0 - 24.5%). A margin of 2 mm reduced that probability to < 0.001% in all patients. On-line position correction does result in an altered target coverage, due to changes in average path length after position correction. An extra margin can be added to prevent underdosage

Synthesis of carrier-free tritium-labeled queen bee pheromone

International Nuclear Information System (INIS)

Webster, F.X.; Prestwich, G.D.

1988-01-01

A short synthesis of [4,5- 3 H 2 ] (E)-9-oxo-2-decenoic acid (ODA), a high-specific-activity tritium-containing isotopomer of the queen bee pheromone, is described. Catalytic tritiation of the ketal of ethyl 9-oxo-4-decenoate introduces tritium into two positions, one of which is completely unactivated. Subsequent transformation by selenation, oxidation, and hydrolysis affords the labeled 9-ODA at >60 Ci/mmol. The material is suitable for biochemical studies of binding and catabolism in ovarian, antennal, and other target tissues

Moving mesh finite element method for finite time extinction of distributed parameter systems with positive exponential feedback; Lokakarya Komputasi dalam Sains dan Teknologi Nuklir VI

Energy Technology Data Exchange (ETDEWEB)

Garnadi, A D [Department of Matematics, Bogor Institute of Agriculture, Bogor (Indonesia)

1997-07-01

In the distributed parameter systems with exponential feedback, non-global existence of solution is not always exist. For some positive initial values, there exist finite time T such that the solution goes to infinity, i.e. finite time extinction or blow-up. Here is present a numerical solution using Moving Mesh Finite Element to solve the distributed parameter systems with exponential feedback close to blow-up time. The numerical behavior of the mesh close to the time of extinction is the prime interest in this study.

Position detector

International Nuclear Information System (INIS)

Hayakawa, Toshifumi.

1985-01-01

Purpose: To enable to detect the position of an moving object in a control rod position detector, stably in a digital manner at a high accuracy and free from the undesired effects of circumstantial conditions such as the reactor temperature. Constitution: Coils connected in parallel with each other are disposed along the passage of a moving object and variable resistors and relays are connected in series with each of the coils respectively. Light emitting diodes is connected in series with the contacts of the respective relays. The resistance value of the variable resistors are adjusted depending on the changes in the circumstantial conditions and temperature distribution upon carrying out the positional detection. When the object is inserted into a coils, the relevant relay is deenergized, by which the relay contacts are closed to light up the diode. In the same manner, as the object is successively inserted into the coils, the diodes are lighted-up successively thereby enabling highly accurate and stable positional detection in a digital manner, free from the undesired effects of the circumstantial conditions. (Horiuchi, T.)

Students’ strategies for position-taking in transnational education

DEFF Research Database (Denmark)

Li, Jin Hui

2016-01-01

The article illuminates the positions distributed and the strategies for position-taking which students pursue in order to transform or preserve their positions in a classroom with a transnational context where students have different national and international education experiences. Furthermore...

Distributed stabilisation of spatially invariant systems: positive polynomial approach

Czech Academy of Sciences Publication Activity Database

Augusta, Petr; Hurák, Z.

2013-01-01

Roč. 24, Č. 1 (2013), s. 3-21 ISSN 1573-0824 R&D Projects: GA MŠk(CZ) 1M0567 Institutional research plan: CEZ:AV0Z10750506 Institutional support: RVO:67985556 Keywords : Multidimensional systems * Algebraic approach * Control design * Positiveness Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2013/TR/augusta-0382623.pdf

Fitness consequences of habitat variability, trophic position, and energy allocation across the depth distribution of a coral-reef fish

Science.gov (United States)

Goldstein, E. D.; D'Alessandro, E. K.; Sponaugle, S.

2017-09-01

Environmental clines such as latitude and depth that limit species' distributions may be associated with gradients in habitat suitability that can affect the fitness of an organism. With the global loss of shallow-water photosynthetic coral reefs, mesophotic coral ecosystems ( 30-150 m) may be buffered from some environmental stressors, thereby serving as refuges for a range of organisms including mobile obligate reef dwellers. Yet habitat suitability may be diminished at the depth boundary of photosynthetic coral reefs. We assessed the suitability of coral-reef habitats across the majority of the depth distribution of a common demersal reef fish ( Stegastes partitus) ranging from shallow shelf (SS, restrict foraging. Fish in MP environments had a broader diet niche, higher trophic position, and higher muscle C:N ratios compared to shallower environments. High C:N ratios suggest increased tissue lipid content in fish in MP habitats that coincided with higher investment in reproduction based on gonado-somatic index. These results suggest that peripheral MP reefs are suitable habitats for demersal reef fish and may be important refuges for organisms common on declining shallow coral reefs.

Method of forecasting power distribution

International Nuclear Information System (INIS)

Kaneto, Kunikazu.

1981-01-01

Purpose: To obtain forecasting results at high accuracy by reflecting the signals from neutron detectors disposed in the reactor core on the forecasting results. Method: An on-line computer transfers, to a simulator, those process data such as temperature and flow rate for coolants in each of the sections and various measuring signals such as control rod positions from the nuclear reactor. The simulator calculates the present power distribution before the control operation. The signals from the neutron detectors at each of the positions in the reactor core are estimated from the power distribution and errors are determined based on the estimated values and the measured values to determine the smooth error distribution in the axial direction. Then, input conditions at the time to be forecast are set by a data setter. The simulator calculates the forecast power distribution after the control operation based on the set conditions. The forecast power distribution is corrected using the error distribution. (Yoshino, Y.)

Negative density-distribution relationship in butterflies

Directory of Open Access Journals (Sweden)

Kotiaho Janne S

2005-03-01

Full Text Available Abstract Background Because "laws of nature" do not exist in ecology, much of the foundations of community ecology rely on broad statistical generalisations. One of the strongest generalisations is the positive relationship between density and distribution within a given taxonomic assemblage; that is, locally abundant species are more widespread than locally sparse species. Several mechanisms have been proposed to create this positive relationship, and the testing of these mechanisms is attracting increasing attention. Results We report a strong, but counterintuitive, negative relationship between density and distribution in the butterfly fauna of Finland. With an exceptionally comprehensive data set (data includes all 95 resident species in Finland and over 1.5 million individuals, we have been able to submit several of the mechanisms to powerful direct empirical testing. Without exception, we failed to find evidence for the proposed mechanisms creating a positive density-distribution relationship. On the contrary, we found that many of the mechanisms are equally able to generate a negative relationship. Conclusion We suggest that one important determinant of density-distribution relationships is the geographical location of the study: on the edge of a distribution range, suitable habitat patches are likely to be more isolated than in the core of the range. In such a situation, only the largest and best quality patches are likely to be occupied, and these by definition can support a relatively dense population leading to a negative density-distribution relationship. Finally, we conclude that generalizations about the positive density-distribution relationship should be made more cautiously.

Negative density-distribution relationship in butterflies.

Science.gov (United States)

Päivinen, Jussi; Grapputo, Alessandro; Kaitala, Veijo; Komonen, Atte; Kotiaho, Janne S; Saarinen, Kimmo; Wahlberg, Niklas

2005-03-01

Because "laws of nature" do not exist in ecology, much of the foundations of community ecology rely on broad statistical generalisations. One of the strongest generalisations is the positive relationship between density and distribution within a given taxonomic assemblage; that is, locally abundant species are more widespread than locally sparse species. Several mechanisms have been proposed to create this positive relationship, and the testing of these mechanisms is attracting increasing attention. We report a strong, but counterintuitive, negative relationship between density and distribution in the butterfly fauna of Finland. With an exceptionally comprehensive data set (data includes all 95 resident species in Finland and over 1.5 million individuals), we have been able to submit several of the mechanisms to powerful direct empirical testing. Without exception, we failed to find evidence for the proposed mechanisms creating a positive density-distribution relationship. On the contrary, we found that many of the mechanisms are equally able to generate a negative relationship. We suggest that one important determinant of density-distribution relationships is the geographical location of the study: on the edge of a distribution range, suitable habitat patches are likely to be more isolated than in the core of the range. In such a situation, only the largest and best quality patches are likely to be occupied, and these by definition can support a relatively dense population leading to a negative density-distribution relationship. Finally, we conclude that generalizations about the positive density-distribution relationship should be made more cautiously.

High-resolution studies of tropolone in the S0 and S1 electronic states: isotope driven dynamics in the zero-point energy levels.

Science.gov (United States)

Keske, John C; Lin, Wei; Pringle, Wallace C; Novick, Stewart E; Blake, Thomas A; Plusquellic, David F

2006-02-21

Rotationally resolved microwave (MW) and ultraviolet (UV) spectra of jet-cooled tropolone have been obtained in S(0) and S(1) electronic states using Fourier-transform microwave and UV-laser/molecular-beam spectrometers. In the ground electronic state, the MW spectra of all heavy-atom isotopomers including one (18)O and four (13)C isotopomers were observed in natural abundance. The OD isotopomer was obtained from isotopically enriched samples. The two lowest tunneling states of each isotopomer except (18)O have been assigned. The observed inversion splitting for the OD isotopomer is 1523.227(5) MHz. For the asymmetric (13)C structures, the magnitudes of tunneling-rotation interactions are found to diminish with decreasing distance between the heavy atom and the tunneling proton. In the limit of closest approach, the 0(+) state of (18)O was well fitted to an asymmetric rotor Hamiltonian, reflecting significant changes in the tautomerization dynamics. Comparisons of the substituted atom coordinates with theoretical predictions at the MP2/aug-cc-pVTZ level of theory suggest the localized 0(+) and 0(-) wave functions of the heavier isotopes favor the C-OH and C=O forms of tropolone, respectively. The only exception occurs for the (13)C-OH and (13)C[Double Bond]O structures which correlate to the 0(-) and 0(+) states, respectively. These preferences reflect kinetic isotope effects as quantitatively verified by the calculated zero-point energy differences between members of the asymmetric atom pairs. From rotationally resolved data of the 0(+) <--0(+) and 0(-) <--0(-) bands in S(1), line-shape fits have yielded Lorentzian linewidths that differ by 12.2(16) MHz over the 19.88(4) cm(-1) interval in S(1). The fluorescence decay rates together with previously reported quantum yield data give nonradiative decay rates of 7.7(5) x 10(8) and 8.5(5) x 10(8) s(-1) for the 0(+) and 0(-) levels of the S(1) state of tropolone.

Pathway confirmation and flux analysis of central metabolic pathways in Desulfovibrio vulgaris Hildenborough using Gas Chromatography-Mass Spectrometry and Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry

International Nuclear Information System (INIS)

Tang, Yinjie; Pingitore, Francesco; Mukhopadhyay, Aindrila; Phan, Richard; Hazen, Terry C.; Keasling, Jay D.

2007-01-01

Flux distribution in central metabolic pathways of Desulfovibrio vulgaris Hildenborough was examined using 13C tracer experiments. Consistent with the current genome annotation and independent evidence from enzyme activity assays, the isotopomer results from both GC-MS and Fourier Transform-Ion Cyclotron Resonance mass spectrometry (FT-ICR MS) indicate the lack of oxidatively functional TCA cycle and an incomplete pentose phosphate pathway. Results from this study suggest that fluxes through both pathways are limited to biosynthesis. The data also indicate that >80 percent of the lactate was converted to acetate and the reactions involved are the primary route of energy production (NAD(P)H and ATP production). Independent of the TCA cycle, direct cleavage of acetyl-CoA to CO and 5,10-methyl-THF also leads to production of NADH and ATP. Although the genome annotation implicates a ferredoxin-dependent oxoglutarate synthase, isotopic evidence does not support flux through this reaction in either the oxidative or reductive mode; therefore, the TCA cycle is incomplete. FT-ICR MS was used to locate the labeled carbon distribution in aspartate and glutamate and confirmed the presence of an atypical enzyme for citrate formation suggested in previous reports (the citrate synthesized by this enzyme is the isotopic antipode of the citrate synthesized by the (S)-citrate synthase). These findings enable a better understanding of the relation between genome annotation and actual metabolic pathways in D. vulgaris, and also demonstrate FT-ICR MS as a powerful tool for isotopomer analysis, overcoming problems in both GC-MS and NMR spectroscopy

Approximations to the electron energy distribution and positive column models for low-pressure discharge light sources

International Nuclear Information System (INIS)

Lister, G G; Sheverev, V A; Uhrlandt, D

2002-01-01

The applicability of 'fluid' models based on analytic approximations of the electron energy distribution function (EEDF) and of kinetic models for low-pressure discharge light sources is discussed. Traditionally, 'fluid' models of fluorescent lamps assume that the EEDF is Maxwellian up to the energy of the first excited state. It is shown that such an approach is sufficiently accurate in most cases of conventional as well as of 'highly loaded' fluorescent lamps. However, this assumption is strongly violated for many rare gas glow discharges for mercury free light sources. As an example, a neon dc discharge is studied. The densities of the four lowest excited states and the electric field have been measured. The experimental results can be fairly well reproduced by a kinetic positive column model. This article was scheduled to appear in issue 14 of J. Phys. D: Appl. Phys. To access this special issue please follow this link: http://stacks.iop.org/0022-3727/35/i=14/

The regiochemical distribution of positive charges along cholesterol polyamine carbamates plays significant roles in modulating DNA binding affinity and lipofection.

Science.gov (United States)

Geall, A J; Eaton, M A; Baker, T; Catterall, C; Blagbrough, I S

1999-10-15

We have quantified the effects of the regiochemical distribution of positive charges along the polyamine moiety in lipopolyamines for DNA molecular recognition. High affinity binding leads to charge neutralisation, DNA condensation and ultimately to lipofection. Binding affinities for calf thymus DNA were determined using an ethidium bromide displacement assay and condensation was detected by changes in turbidity using light scattering. The in vitro transfection competence of cholesterol polyamine carbamates was measured in CHO cells. In the design of DNA condensing and transfecting agents for non-viral gene therapy, the interrelationship of ammonium ions, not just their number, must be considered.

Position-sensitive proportional counter

International Nuclear Information System (INIS)

Kopp, M.K.

1980-01-01

A position-sensitive proportional counter circuit uses a conventional (low-resistance, metal-wire anode) counter for spatial resolution of an ionizing event along the anode, which functions as an RC line. A pair of preamplifiers at the anode ends act as stabilized active-capacitance loads, each comprising a series-feedback, low-noise amplifier and a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at the anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction of handling of the anodes, and stabilizes the anode resistivity at high count rates (>10 6 counts/sec). (author)

Strategic positioning. Part 2: Positioning challenges in an evolving health care marketplace.

Science.gov (United States)

Kauer, R T; Berkowitz, E

1997-01-01

Why is strategic positioning so important to health care organizations struggling in a managed care environment and what are the sources of value? In Part 1 of this article, entitled "The Sources of Value under Managed Care," the authors presented four sources of value relative to the evolution of the market from fee-for-service to managed care. These value sources are: (1) assets, (2) price/performance, (3) distribution, and, ultimately, (4) capabilities and brand equity. In this article, the authors further elaborate on the sources of value as the market moves beyond the historical fee-for-service position to a managed care marketplace. Part 2 presents the marketing and financial challenges to organizational positioning and performance across the four stages of managed care.

[Positive Distribution Rate of Coombs Test in Patients with Clinical Anemia and Blood Transfusion and Its Effect on Clinical Blood Transfusion].

Science.gov (United States)

Wu, Gang; Duan, Yu-Han

2018-02-01

To study the positive distribution rate of Coombs test in patients with clinical anemia and blood transfusion, and its effect on clinical blood transfusion. Seventy patients with hemoglobin level in the normal range were enrolled into control group, while 130 patients with anemia or blood transfusion who' s hemoglobin level was lower comfirmed by micro-column gel antihuman globin detection card and 70 surgical patients with anemia or blood transfusion who' s hemoglobin level was lower comfirmed by micro-column gel anti-human globin card were enrolled into anemia or blood transfusion (A or BT) group. And coomb' s test performed for all the patients, in which the positive patients in Department of Internal Medicine need to be re-typed. Among 70 surgical patients with anemia or blood transfusion, 14 cases were directly detected to be anti-human globine positive with detection rate 20%; among 130 internal medicine patients with anemia or blood transfusion, 54 cases were directly detected to be anti-human globine positive with detection rate 41.4%. Among 270 cases, the highest positive rate (66.7%) was observed in patients with 50-59 g/L of hemoglobin. According to type test, the samples of 54 patients with anemia in Department of Internal Medicine, who were directly selected to be anti-human globin positive, could be divided into anti-C3d(7 cases, accounting for 13.0%), anti-IgG(12 cases accounting for, 22.2%) and anti-C3d+anti-IgG(35 cases, accounting for 64.8%), while according to diseases, the anti-human globin positive ratio was high in tumor cancer, hephropathy and gastroenteropathy patients, and patients in intensive care unit, moreover the blood transfusion frequency of these patients was higher than that of patients with anti-human globin negative(Pblood transfusion, so as to ensure the effectiveness of blood transfusion.

Simultaneous measurement of neuronal and glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate

Science.gov (United States)

Deelchand, Dinesh K.; Nelson, Christopher; Shestov, Alexander A.; Uğurbil, Kâmil; Henry, Pierre-Gilles

2009-02-01

In this work the feasibility of measuring neuronal-glial metabolism in rat brain in vivo using co-infusion of [1,6- 13C 2]glucose and [1,2- 13C 2]acetate was investigated. Time courses of 13C spectra were measured in vivo while infusing both 13C-labeled substrates simultaneously. Individual 13C isotopomers (singlets and multiplets observed in 13C spectra) were quantified automatically using LCModel. The distinct 13C spectral pattern observed in glutamate and glutamine directly reflected the fact that glucose was metabolized primarily in the neuronal compartment and acetate in the glial compartment. Time courses of concentration of singly and multiply-labeled isotopomers of glutamate and glutamine were obtained with a temporal resolution of 11 min. Although dynamic metabolic modeling of these 13C isotopomer data will require further work and is not reported here, we expect that these new data will allow more precise determination of metabolic rates as is currently possible when using either glucose or acetate as the sole 13C-labeled substrate.

Measurements of the microwave spectrum, Re-H bond length, and Re quadrupole coupling for HRe(CO)5

Science.gov (United States)

Kukolich, Stephen G.; Sickafoose, Shane M.

1993-11-01

Rotational transition frequencies for rhenium pentacarbonyl hydride were measured in the 4-10 GHz range using a Flygare-Balle type microwave spectrometer. The rotational constants and Re nuclear quadrupole coupling constants for the four isotopomers, (1) H187Re(CO)5, (2) H185Re(CO)5, (3) D187Re(CO)5, and (4) D185Re(CO)5, were obtained from the spectra. For the most common isotopomer, B(1)=818.5464(2) MHz and eq Q(187Re)=-900.13(3) MHz. The Re-H bond length (r0) determined by fitting the rotational constants is 1.80(1) Å. Although the Re atom is located at a site of near-octahedral symmetry, the quadrupole coupling is large due to the large Re nuclear moments. A 2.7% increase in Re quadrupole coupling was observed for D-substituted isotopomers, giving a rather large isotope effect on the quadrupole coupling. The Cax-Re-Ceq angle is 96(1)°, when all Re-C-O angles are constrained to 180°.

Dyadic distributions

International Nuclear Information System (INIS)

Golubov, B I

2007-01-01

On the basis of the concept of pointwise dyadic derivative dyadic distributions are introduced as continuous linear functionals on the linear space D d (R + ) of infinitely differentiable functions compactly supported by the positive half-axis R + together with all dyadic derivatives. The completeness of the space D' d (R + ) of dyadic distributions is established. It is shown that a locally integrable function on R + generates a dyadic distribution. In addition, the space S d (R + ) of infinitely dyadically differentiable functions on R + rapidly decreasing in the neighbourhood of +∞ is defined. The space S' d (R + ) of dyadic distributions of slow growth is introduced as the space of continuous linear functionals on S d (R + ). The completeness of the space S' d (R + ) is established; it is proved that each integrable function on R + with polynomial growth at +∞ generates a dyadic distribution of slow growth. Bibliography: 25 titles.

Positivity of the English Language

Science.gov (United States)

Kloumann, Isabel M.; Danforth, Christopher M.; Harris, Kameron Decker; Bliss, Catherine A.; Dodds, Peter Sheridan

2012-01-01

Over the last million years, human language has emerged and evolved as a fundamental instrument of social communication and semiotic representation. People use language in part to convey emotional information, leading to the central and contingent questions: (1) What is the emotional spectrum of natural language? and (2) Are natural languages neutrally, positively, or negatively biased? Here, we report that the human-perceived positivity of over 10,000 of the most frequently used English words exhibits a clear positive bias. More deeply, we characterize and quantify distributions of word positivity for four large and distinct corpora, demonstrating that their form is broadly invariant with respect to frequency of word use. PMID:22247779

Positivity of the English language.

Directory of Open Access Journals (Sweden)

Isabel M Kloumann

Full Text Available Over the last million years, human language has emerged and evolved as a fundamental instrument of social communication and semiotic representation. People use language in part to convey emotional information, leading to the central and contingent questions: (1 What is the emotional spectrum of natural language? and (2 Are natural languages neutrally, positively, or negatively biased? Here, we report that the human-perceived positivity of over 10,000 of the most frequently used English words exhibits a clear positive bias. More deeply, we characterize and quantify distributions of word positivity for four large and distinct corpora, demonstrating that their form is broadly invariant with respect to frequency of word use.

Method of estimating the reactor power distribution

International Nuclear Information System (INIS)

Mitsuta, Toru; Fukuzaki, Takaharu; Doi, Kazuyori; Kiguchi, Takashi.

1984-01-01

Purpose: To improve the calculation accuracy for the power distribution thereby improve the reliability of power distribution monitor. Constitution: In detector containing strings disposed within a reactor core, movable type neutron flux monitors are provided in addition to position fixed type neutron monitors conventionally disposed so far. Upon periodical monitoring, a power distribution X1 is calculated from a physical reactor core model. Then, a higher power position X2 is detected by position detectors and value X2 is sent to a neutron flux monitor driving device to displace the movable type monitors to a higher power position in each of the strings. After displacement, the value X1 is amended by an amending device using measured values from the movable type and fixed type monitors and the amended value is sent to a reactor core monitor device. Upon failure of the fixed type monitors, the position is sent to the monitor driving device and the movable monitors are displaced to that position for measurement. (Sekiya, K.)

Quantitative analysis of 15N-labeled positional isomers of glutamine and citrulline via electrospray ionization tandem mass spectrometry of their dansyl derivatives.

Science.gov (United States)

Marini, Juan C

2011-05-15

The enteral metabolisms of glutamine and citrulline are intertwined because, while glutamine is one of the main fuel sources for the enterocyte, citrulline is one of its products. It has been shown that the administration of (15)N-labeled glutamine results in the incorporation of the (15)N label into citrulline, but it is not clear which of the three nitrogen groups of citrulline is actually labeled. To determine the (15)N-enrichment of the positional isomers of glutamine and citrulline, a rapid liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed. The amino acids were analyzed as their dansyl derivatives. The product ion resulting from the loss of NH(3) from the omega carbon allows for the determination of the enrichment of the ureido (citrulline) or amido groups (glutamine). The protonated pyrrolidine (citrulline) or 5-oxopyrrolidine (glutamine) product ion contains the 2-N (amino group) and is used to determine its enrichment. The method described showed no ion suppression and a wide dynamic range ranging from 1.3 picomoles to 2 nanomoles for citrulline. Background samples and standards resulted in enrichments not different from those theoretically expected. The enrichment curves for the different glutamine and citrulline isotopomers were linear (R(2)  > 0.998) over the range of enrichments studied. The method developed provides an additional insight into the metabolism of glutamine and citrulline tracing the precursor-product relationship between these two amino acids. Copyright © 2011 John Wiley & Sons, Ltd.

An improved algorithm to generate a Wi-Fi fingerprint database for indoor positioning.

Science.gov (United States)

Chen, Lina; Li, Binghao; Zhao, Kai; Rizos, Chris; Zheng, Zhengqi

2013-08-21

The major problem of Wi-Fi fingerprint-based positioning technology is the signal strength fingerprint database creation and maintenance. The significant temporal variation of received signal strength (RSS) is the main factor responsible for the positioning error. A probabilistic approach can be used, but the RSS distribution is required. The Gaussian distribution or an empirically-derived distribution (histogram) is typically used. However, these distributions are either not always correct or require a large amount of data for each reference point. Double peaks of the RSS distribution have been observed in experiments at some reference points. In this paper a new algorithm based on an improved double-peak Gaussian distribution is proposed. Kurtosis testing is used to decide if this new distribution, or the normal Gaussian distribution, should be applied. Test results show that the proposed algorithm can significantly improve the positioning accuracy, as well as reduce the workload of the off-line data training phase.

Thinking positively: The genetics of high intelligence

Science.gov (United States)

Shakeshaft, Nicholas G.; Trzaskowski, Maciej; McMillan, Andrew; Krapohl, Eva; Simpson, Michael A.; Reichenberg, Avi; Cederlöf, Martin; Larsson, Henrik; Lichtenstein, Paul; Plomin, Robert

2015-01-01

High intelligence (general cognitive ability) is fundamental to the human capital that drives societies in the information age. Understanding the origins of this intellectual capital is important for government policy, for neuroscience, and for genetics. For genetics, a key question is whether the genetic causes of high intelligence are qualitatively or quantitatively different from the normal distribution of intelligence. We report results from a sibling and twin study of high intelligence and its links with the normal distribution. We identified 360,000 sibling pairs and 9000 twin pairs from 3 million 18-year-old males with cognitive assessments administered as part of conscription to military service in Sweden between 1968 and 2010. We found that high intelligence is familial, heritable, and caused by the same genetic and environmental factors responsible for the normal distribution of intelligence. High intelligence is a good candidate for “positive genetics” — going beyond the negative effects of DNA sequence variation on disease and disorders to consider the positive end of the distribution of genetic effects. PMID:25593376

Catabolism of Branched Chain Amino Acids Contributes Significantly to Synthesis of Odd-Chain and Even-Chain Fatty Acids in 3T3-L1 Adipocytes.

Directory of Open Access Journals (Sweden)

Scott B Crown

Full Text Available The branched chain amino acids (BCAA valine, leucine and isoleucine have been implicated in a number of diseases including obesity, insulin resistance, and type 2 diabetes mellitus, although the mechanisms are still poorly understood. Adipose tissue plays an important role in BCAA homeostasis by actively metabolizing circulating BCAA. In this work, we have investigated the link between BCAA catabolism and fatty acid synthesis in 3T3-L1 adipocytes using parallel 13C-labeling experiments, mass spectrometry and model-based isotopomer data analysis. Specifically, we performed parallel labeling experiments with four fully 13C-labeled tracers, [U-13C]valine, [U-13C]leucine, [U-13C]isoleucine and [U-13C]glutamine. We measured mass isotopomer distributions of fatty acids and intracellular metabolites by GC-MS and analyzed the data using the isotopomer spectral analysis (ISA framework. We demonstrate that 3T3-L1 adipocytes accumulate significant amounts of even chain length (C14:0, C16:0 and C18:0 and odd chain length (C15:0 and C17:0 fatty acids under standard cell culture conditions. Using a novel GC-MS method, we demonstrate that propionyl-CoA acts as the primer on fatty acid synthase for the production of odd chain fatty acids. BCAA contributed significantly to the production of all fatty acids. Leucine and isoleucine contributed at least 25% to lipogenic acetyl-CoA pool, and valine and isoleucine contributed 100% to lipogenic propionyl-CoA pool. Our results further suggest that low activity of methylmalonyl-CoA mutase and mass action kinetics of propionyl-CoA on fatty acid synthase result in high rates of odd chain fatty acid synthesis in 3T3-L1 cells. Overall, this work provides important new insights into the connection between BCAA catabolism and fatty acid synthesis in adipocytes and underscores the high capacity of adipocytes for metabolizing BCAA.

DISTRIBUTION MANAGEMENT IN COMPANY X

OpenAIRE

Agnieszka Wójcik-Mazur; Karina Wieczorek

2012-01-01

The subject of this publication is the problem of distribution management, exemplified by Company X. The process has been defined by analysing the conditions necessary to satisfy prospects’ needs and create the market position of a business entity. The paper focuses on the basic features of distribution system and the character of distribution channels.The assessment of distribution management has been illustrated with an example of Company X. The subjects of interest are: the dynamics of ord...

Weak positive cloud-to-ground flashes in Northeastern Colorado

Science.gov (United States)

Lopez, Raul E.; Maier, Michael W.; Garcia-Miguel, Juan A.; Holle, Ronald L.

1991-01-01

The frequency distributions of the peak magnetic field associated with the first detected return stroke of positive and negative cloud-to-ground (CG) flashes were studied using lightning data from northeastern Colorado. These data were obtained during 1985 with a medium-to-high gain network of three direction finders (DF's). The median signal strength of positive flashes was almost two times that of the negatives for flashes within 300 km of the DF's, which have an inherent detection-threshold bias that tends to discriminate against weak signals. This bias increases with range, and affects the detection of positive and negative flashes in different ways, because of the differing character of their distributions. Positive flashes appear to have a large percentage of signals clustered around very weak values that are lost to the medium-to-high gain Colorado Detection System very quickly with increasing range. The resulting median for positive signals could thus appear to be much larger than the median for negative signals, which are more clustered around intermediate values. When only flashes very close to the DF's are considered, however, the two distributions have almost identical medians. The large percentage of weak positive signals detected close to the DF's has not been explored previously. They have been suggested to come from intracloud discharges and thus are improperly classified as CG flashes. Evidence in hand, points to their being real positive, albeit weak CG flashes. Whether or not they are real positive ground flashes, it is important to be aware of their presence in data from magnetic DF networks.

Fourier-positivity constraints on QCD dipole models

Directory of Open Access Journals (Sweden)

Bertrand G. Giraud

2016-09-01

Full Text Available Fourier-positivity (F-positivity, i.e. the mathematical property that a function has a positive Fourier transform, can be used as a constraint on the parametrization of QCD dipole-target cross-sections or Wilson line correlators in transverse position space r. They are Bessel transforms of positive transverse momentum dependent gluon distributions. Using mathematical F-positivity constraints on the limit r→0 behavior of the dipole amplitudes, we identify the common origin of the violation of F-positivity for various, however phenomenologically convenient, dipole models. It is due to the behavior r2+ϵ, ϵ>0 softer, even slightly, than color transparency. F-positivity seems thus to conflict with the present dipole formalism when it includes a QCD running coupling constant α(r.

Position, Energy, and Transit Time Distributions in a Hemispherical Deflector Analyzer with Position Sensitive Detector

Directory of Open Access Journals (Sweden)

Omer Sise

2015-01-01

Full Text Available Practical analytic equations, for the ideal field, and numerical results from SIMION simulations, for the fringing field, are presented for the exit radius rπ and transit time tπ of electrons in a hemispherical deflector analyzer (HDA over a wide range of analyzer parameters. Results are presented for a typically dimensioned HDA with mean radius R-=101.6 mm and interradial separation ΔR=R2-R1=58.4 mm able to accommodate a 40 mm diameter position sensitive detector (PSD. Results for three different entry positions R0 are compared: R0=R- (the conventional central entry and two displaced (paracentric entries: R0=82.55 mm and R0=116 mm. Exit spreads Δrπ, Δtπ and base energy resolution ΔEB are computed for HDA pass energies E0=10, 100, 500, and 1000 eV, entry aperture sizes Δr0≤1.5 mm, entry angular spreads |αmax|≤5°, and an electron beam with relative energy spread δE/E0≤0.4%. Overall, under realistic conditions, both paracentric entries demonstrate near ideal field behavior and clear superiority over the conventional entry at R0=R-. The R0=82.55 mm entry has better absolute energy and time spread resolutions, while the R0=116 mm has better relative energy resolutions, both offering attractive alternatives for time-of-flight and coincidence applications where both energy and timing resolutions are important.

Current and potential distributions on positive plates with conductive Pb{sub 3}O{sub 4} and BaPbO{sub 3} in their formation and discharge

Energy Technology Data Exchange (ETDEWEB)

Guo, Yonglang; Liu, Huan [College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108 (China)

2008-08-15

The positive plates with conductive materials, Pb{sub 3}O{sub 4} and BaPbO{sub 3}, in automotive lead-acid batteries were investigated by measuring their current and potential distributions in the course of formation and discharge. It is found that these two conductive materials, especially Pb{sub 3}O{sub 4}, enhance the formation in the initial stage greatly and that they make the current and potential distributions more uniform. In the discharge, the addition of Pb{sub 3}O{sub 4} increases the capacity of the positive plate, but it is unfavorable to the paste curing and causes poor contact between active mass (AM) particles so that the polarization increases greatly at 3 C discharge rate. The BaPbO{sub 3} additive improves not only the formation but also the discharge performance because of its stability in acidic media and at high polarization. The violent charge at high polarization around the plates in the initial formation can lead to poor AM contact and high polarization resistance. (author)

Distribution of the ACME-arcA gene among meticillin-resistant Staphylococcus haemolyticus and identification of a novel ccr allotype in ACME-arcA-positive isolates.

Science.gov (United States)

Pi, Borui; Yu, Meihong; Chen, Yagang; Yu, Yunsong; Li, Lanjuan

2009-06-01

The aim of this study was to investigate the prevalence and characteristics of ACME (arginine catabolic mobile element)-arcA-positive isolates among meticillin-resistant Staphylococcus haemolyticus (MRSH). ACME-arcA, native arcA and SCCmec elements were detected by PCR. Susceptibilities to 10 antimicrobial agents were compared between ACME-arcA-positive and -negative isolates by chi-square test. PFGE was used to investigate the clonal relatedness of ACME-arcA-positive isolates. The phylogenetic relationships of ACME-arcA and native arcA were analysed using the neighbour-joining methods of mega software. A total of 42 (47.7 %) of 88 isolates distributed in 13 PFGE types were positive for the ACME-arcA gene. There were no significant differences in antimicrobial susceptibility between ACME-arcA-positive and -negative isolates. A novel ccr allotype (ccrAB(SHP)) was identified in ACME-arcA-positive isolates. Among 42 ACME-arcA-positive isolates: 8 isolates harboured SCCmec V, 8 isolates harboured class C1 mec complex and ccrAB(SHP); 22 isolates harbouring class C1 mec complex and 4 isolates harbouring class C2 mec complex were negative for all known ccr allotypes. The ACME-arcA-positive isolates were first found in MRSH with high prevalence and clonal diversity, which suggests a mobility of ACME within MRSH. The results from this study revealed that MRSH is likely to be one of the potential reservoirs of ACME for Staphylococcus aureus.

Application of the NAVSTAR/GLOBAL positioning system on instrumented ranges

OpenAIRE

Reinhart, William L.

1981-01-01

Approved for public release; distribution is unlimited This report treats the application of the NAVSTAR/Global Positioning System as the Position/Location System in Real Time Casualty Assessment experiments. The desirable characteristics of a position/location system are listed. A current position/location system, the Range Measuring System, is used as a comparison reference for the Global Positioning System. Operation and parameters of the Global Positioning System are presented. A d...

Dynamic analysis of CO₂ labeling and cell respiration using membrane-inlet mass spectrometry.

Science.gov (United States)

Yang, Tae Hoon

2014-01-01

Here, we introduce a mass spectrometry-based analytical method and relevant technical details for dynamic cell respiration and CO2 labeling analysis. Such measurements can be utilized as additional information and constraints for model-based (13)C metabolic flux analysis. Dissolved dynamics of oxygen consumption and CO2 mass isotopomer evolution from (13)C-labeled tracer substrates through different cellular processes can be precisely measured on-line using a miniaturized reactor system equipped with a membrane-inlet mass spectrometer. The corresponding specific rates of physiologically relevant gases and CO2 mass isotopomers can be quantified within a short-term range based on the liquid-phase dynamics of dissolved fermentation gases.

Positioning effects on lung ventilation in older normal subjects: a technegas study

International Nuclear Information System (INIS)

Krieg, S.; McCarren, B.; Alison, J.; Cowell, S.F.; Leiper, C.; Bankstown-Lidcombe Hospital, Sydney, NSW; El Zein, H.

2002-01-01

Full text: While the effects of positioning on the distribution of ventilation in the lungs of younger subjects has been relatively well investigated, this is not so in the older age group. Known age-associated changes in the respiratory system are proposed to alter the distribution of ventilation in the lungs of older people. The aim of the present study was therefore to determine the effects of positioning on the distribution of ventilation in the lungs of older normal subjects. The distribution of ventilation in upright sitting and right side lying was measured in ten subjects using Technegas lung ventilation during tidal breathing. In the upright sitting position ventilation was preferentially distributed to the middle and basal regions (dependent regions). Right side lying ventilation was preferentially distributed to the right lung (dependent region). These results suggest that preferential distribution of ventilation to the dependent lung regions in older subjects is mainly due to the gravity-dependent gradient in pleural pressure. It is proposed that this distribution may partly result from loss of elasticity in the lungs with ageing. Predominantly, the distribution of ventilation in the lungs of older normal subjects in our study is similar to that previously described in younger subjects (Amis et al., 1984, Kaneko et al, 1966, Milic-Emili et al, 1966. This suggests that a similar pleural pressure gradient may exist in the lungs of older and younger subjects. This is an important implication as the majority of patients that physiotherapists treat with cardiopulmonary dysfunction are in the older age group. Further research is required to determine the effects of positioning on the distribution of ventilation in older patients with cardiopulmonary dysfunction to enable direct clinical implications to be made. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

Multivariate log-skew-elliptical distributions with applications to precipitation data

KAUST Repository

Marchenko, Yulia V.

2009-07-13

We introduce a family of multivariate log-skew-elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log-t distribution, the positive moments of the log-skew-t distribution do not exist. Our emphasis is on two special cases, the log-skew-normal and log-skew-t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. © 2009 John Wiley & Sons, Ltd.

Multivariate log-skew-elliptical distributions with applications to precipitation data

KAUST Repository

Marchenko, Yulia V.; Genton, Marc G.

2009-01-01

We introduce a family of multivariate log-skew-elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log-t distribution, the positive moments of the log-skew-t distribution do not exist. Our emphasis is on two special cases, the log-skew-normal and log-skew-t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. © 2009 John Wiley & Sons, Ltd.

Moment Distributions of Phase Type

DEFF Research Database (Denmark)

Bladt, Mogens; Nielsen, Bo Friis

In this paper we prove that the class of distributions on the positive reals with a rational Laplace transform, also known as matrix-exponential distributions, is closed under formation of moment distributions. In particular, the results are hence valid for the well known class of phase-type dist...... alternative representation in terms of sub{intensity matrices. Finally we are able to nd explicit expressions for both the Lorenz curve and the Gini index....

Distributed analysis at LHCb

International Nuclear Information System (INIS)

Williams, Mike; Egede, Ulrik; Paterson, Stuart

2011-01-01

The distributed analysis experience to date at LHCb has been positive: job success rates are high and wait times for high-priority jobs are low. LHCb users access the grid using the GANGA job-management package, while the LHCb virtual organization manages its resources using the DIRAC package. This clear division of labor has benefitted LHCb and its users greatly; it is a major reason why distributed analysis at LHCb has been so successful. The newly formed LHCb distributed analysis support team has also proved to be a success.

The Beta Transmuted Weibull Distribution

Directory of Open Access Journals (Sweden)

Manisha Pal

2014-06-01

Full Text Available The paper introduces a beta transmuted Weibull distribution, which contains a number ofdistributions as special cases. The properties of the distribution are discussed and explicit expressions are derived for the mean deviations, Bonferroni and Lorenz curves, and reliability. The distribution and moments of order statistics are also studied. Estimation of the model parameters by the method of maximum likelihood is discussed. The log beta transmuted Weibull model is introduced to analyze censored data. Finally, the usefulness of the new distribution in analyzing positive data is illustrated.

Satisfying positivity requirement in the Beyond Complex Langevin approach

Directory of Open Access Journals (Sweden)

Wyrzykowski Adam

2018-01-01

Full Text Available The problem of finding a positive distribution, which corresponds to a given complex density, is studied. By the requirement that the moments of the positive distribution and of the complex density are equal, one can reduce the problem to solving the matching conditions. These conditions are a set of quadratic equations, thus Groebner basis method was used to find its solutions when it is restricted to a few lowest-order moments. For a Gaussian complex density, these approximate solutions are compared with the exact solution, that is known in this special case.

Satisfying positivity requirement in the Beyond Complex Langevin approach

Science.gov (United States)

Wyrzykowski, Adam; Ruba, Błażej Ruba

2018-03-01

The problem of finding a positive distribution, which corresponds to a given complex density, is studied. By the requirement that the moments of the positive distribution and of the complex density are equal, one can reduce the problem to solving the matching conditions. These conditions are a set of quadratic equations, thus Groebner basis method was used to find its solutions when it is restricted to a few lowest-order moments. For a Gaussian complex density, these approximate solutions are compared with the exact solution, that is known in this special case.

Detector Position Estimation for PET Scanners.

Science.gov (United States)

Pierce, Larry; Miyaoka, Robert; Lewellen, Tom; Alessio, Adam; Kinahan, Paul

2012-06-11

Physical positioning of scintillation crystal detector blocks in Positron Emission Tomography (PET) scanners is not always exact. We test a proof of concept methodology for the determination of the six degrees of freedom for detector block positioning errors by utilizing a rotating point source over stepped axial intervals. To test our method, we created computer simulations of seven Micro Crystal Element Scanner (MiCES) PET systems with randomized positioning errors. The computer simulations show that our positioning algorithm can estimate the positions of the block detectors to an average of one-seventh of the crystal pitch tangentially, and one-third of the crystal pitch axially. Virtual acquisitions of a point source grid and a distributed phantom show that our algorithm improves both the quantitative and qualitative accuracy of the reconstructed objects. We believe this estimation algorithm is a practical and accurate method for determining the spatial positions of scintillation detector blocks.

Detector position estimation for PET scanners

International Nuclear Information System (INIS)

Pierce, Larry; Miyaoka, Robert; Lewellen, Tom; Alessio, Adam; Kinahan, Paul

2012-01-01

Physical positioning of scintillation crystal detector blocks in Positron Emission Tomography (PET) scanners is not always exact. We test a proof of concept methodology for the determination of the six degrees of freedom for detector block positioning errors by utilizing a rotating point source over stepped axial intervals. To test our method, we created computer simulations of seven Micro Crystal Element Scanner (MiCES) PET systems with randomized positioning errors. The computer simulations show that our positioning algorithm can estimate the positions of the block detectors to an average of one-seventh of the crystal pitch tangentially, and one-third of the crystal pitch axially. Virtual acquisitions of a point source grid and a distributed phantom show that our algorithm improves both the quantitative and qualitative accuracy of the reconstructed objects. We believe this estimation algorithm is a practical and accurate method for determining the spatial positions of scintillation detector blocks.

System for forecasting a reactor power distribution

International Nuclear Information System (INIS)

Motoda, Hiroshi; Nishizawa, Yasuo.

1976-01-01

Purpose: To dispense with frequent running of detector in a BWR type reactor and permit calculation of the prevailing value and forecast value of power distribution in a specified region in an on-line basis. Constitution: The prevailing power distribution P sub(OZ) (where Z indicates a position in the axial direction) at a given position is estimated by prevailing power distribution estimating means, and the average prevailing power distribution Q sub(OZ) in the core is estimated while making correction of a primary neutron distribution model by core average characteristic measuring means. Then, the estimated core average power distribution Q sub(Z) after alteration of the core flow rate or alteration of Xe concentration is estimated by core average power distribution estimating means. At this time, a forecast power distribution P sub(Z) in a specified region after alteration of the flow rate or alteration of the Xe concentration is calculated on the basis of a relation P sub(Z) = (Q sub(Z)/Q sub(OZ)) by using P sub(OZ), Q sub(OZ) and Q sub(Z). The above calculations are carried out in a short period of time by using a process computer. (Ikeda, J.)

Fitting the Probability Distribution Functions to Model Particulate Matter Concentrations

International Nuclear Information System (INIS)

El-Shanshoury, Gh.I.

2017-01-01

The main objective of this study is to identify the best probability distribution and the plotting position formula for modeling the concentrations of Total Suspended Particles (TSP) as well as the Particulate Matter with an aerodynamic diameter<10 μm (PM 10 ). The best distribution provides the estimated probabilities that exceed the threshold limit given by the Egyptian Air Quality Limit value (EAQLV) as well the number of exceedance days is estimated. The standard limits of the EAQLV for TSP and PM 10 concentrations are 24-h average of 230 μg/m 3 and 70 μg/m 3 , respectively. Five frequency distribution functions with seven formula of plotting positions (empirical cumulative distribution functions) are compared to fit the average of daily TSP and PM 10 concentrations in year 2014 for Ain Sokhna city. The Quantile-Quantile plot (Q-Q plot) is used as a method for assessing how closely a data set fits a particular distribution. A proper probability distribution that represents the TSP and PM 10 has been chosen based on the statistical performance indicator values. The results show that Hosking and Wallis plotting position combined with Frechet distribution gave the highest fit for TSP and PM 10 concentrations. Burr distribution with the same plotting position follows Frechet distribution. The exceedance probability and days over the EAQLV are predicted using Frechet distribution. In 2014, the exceedance probability and days for TSP concentrations are 0.052 and 19 days, respectively. Furthermore, the PM 10 concentration is found to exceed the threshold limit by 174 days

Quantum origins of molecular recognition and olfaction in Drosophila.

Science.gov (United States)

Bittner, Eric R; Madalan, Adrian; Czader, Arkadiusz; Roman, Gregg

2012-12-14

The standard model for molecular recognition of an odorant is that receptor sites discriminate by molecular geometry as evidenced that two chiral molecules may smell very differently. However, recent studies of isotopically labeled olfactants indicate that there may be a molecular vibration-sensing component to olfactory reception, specifically in the spectral region around 2300 cm(-1). Here, we present a donor-bridge-acceptor model for olfaction which attempts to explain this effect. Our model, based upon accurate quantum chemical calculations of the olfactant (bridge) in its neutral and ionized states, posits that internal modes of the olfactant are excited impulsively during hole transfer from a donor to acceptor site on the receptor, specifically those modes that are resonant with the tunneling gap. By projecting the impulsive force onto the internal modes, we can determine which modes are excited at a given value of the donor-acceptor tunneling gap. Only those modes resonant with the tunneling gap and are impulsively excited will give a significant contribution to the inelastic transfer rate. Using acetophenone as a test case, our model and experiments on D. melanogaster suggest that isotopomers of a given olfactant give rise to different odorant qualities. These results support the notion that inelastic scattering effects may play a role in discriminating between isotopomers but that this is not a general spectroscopic effect.

5th International Symposium on Positive Systems

CERN Document Server

Farina, Lorenzo; Setola, Roberto; Germani, Alfredo

2017-01-01

This book presents high-quality original contributions on positive systems, including topics such as: monotone dynamical systems in mathematical biology and game theory; mathematical developments for networked systems in biology, chemistry and the social sciences; linear and nonlinear positive operators; dynamical analysis, observation and control of positive distributed parameter systems; stochastic realization theory; biological systems with positive variables and positive controls; iterated function systems; nonnegative dynamic processes; and dimensioning problems for collaborative systems. The book comprises a selection of the best papers presented at the POSTA 2016, the 5th International Symposium on Positive Systems, which was held in Rome, Italy, in September 2016. This conference series represents a targeted response to the growing need for research that reports on and critically discusses a wide range of topics concerning the theory and applications of positive systems.

A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region

International Nuclear Information System (INIS)

Yang, Chang; Su, Z.; Xiao, F.; Zheng, H.

2017-01-01

Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistlermode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct butterfly distributions usually correspond to magnetosonic waves with larger amplitudes and vice versa. The averaged magnetosonic wave amplitude is less than 5 pT in the case of normal and flat-top distributions with a butterfly index BI = 1 but reaches ~ 35–95 pT in the case of distinct butterfly distributions with BI > 1:3. For magnetosonic waves with amplitudes > 50 pT, the occurrence rate of butterfly distribution is above 80%. Our study suggests that energetic electron butterfly distributions in the slot region are primarily caused by magnetosonic waves.

Positions of human dwellings affect few tropical diseases near ...

African Journals Online (AJOL)

user

Some factors that possibly affect tropical disease distribution was investigated in about 500 randomize human dwellings. The studied factors include wild animals, domestic animals, wild plants, cultivated plants, nature of soil, nature of water, positions of human dwellings, nature of building material and position of animal ...

The cyclopropene radical cation: Rovibrational level structure at low energies from high-resolution photoelectron spectra

Energy Technology Data Exchange (ETDEWEB)

Vasilatou, K.; Michaud, J. M.; Baykusheva, D.; Grassi, G.; Merkt, F. [Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich (Switzerland)

2014-08-14

The cyclopropene radical cation (c-C{sub 3}H{sub 4}{sup +}) is an important but poorly characterized three-membered-ring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the X{sup ~+} {sup 2}B{sub 2} ground electronic state of c-C{sub 3}H{sub 4}{sup +} at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C{sub 2v}-symmetric R{sub 0} structure for the ground electronic state of c-C{sub 3}H{sub 4}{sup +}. Two vibrational modes of c-C{sub 3}H{sub 4}{sup +} are found to have vibrational wave numbers below 300 cm{sup −1}, which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ≈110 cm{sup −1} in c-C{sub 3}H{sub 4}{sup +}) to the CH{sub 2} torsional mode (ν{sub 8}{sup +}, A{sub 2} symmetry) and of the second-lowest-frequency mode (≈210 cm{sup −1} in c-C{sub 3}H{sub 4}{sup +}) to a mode combining a CH out-of-plane with a CH{sub 2} rocking motion (ν{sub 15}{sup +}, B{sub 2} symmetry). The potential energy along the CH{sub 2} torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity.

Distributed Cognition in the Management of Design Requirements

OpenAIRE

Hansen, Sean; Lyytinen, Kalle

2009-01-01

In this position statement, we outline a new theoretical framework of the distribution of design requirements processes. Building upon the Theory of Distributed Cognition, we characterize contemporary requirements efforts as distributed cognitive systems in which elements of a design vision are distributed socially, structurally, and temporally. We discuss the various forms of distribution observed in real-world systems development projects and the processes by which representational states ...

Dose deviations caused by positional inaccuracy of multileaf collimator in intensity modulated radiotherapy

International Nuclear Information System (INIS)

Wang, H.C.; Chui, C.S.; Tsai, H.Y.; Chen, C.H.; Tsai, L.F.

2008-01-01

Introduction: Multileaf collimator (MLC) is currently a widely used system in the delivery of intensity modulated radiotherapy (IMRT). The accuracy of the multileaf position plays an important role in the final outcome of the radiation treatment. According to ICRU recommendation, a dose inaccuracy over than 5% of prescribed dose affects treatment results. In order to quantify the influence of leaf positional errors on dose distribution, we set different MLC positional inaccuracy from 0 to 6 mm for step-and-shoot IMRT in clinical cases. Two-dimensional dose distributions of radiotherapy plans with different leaf displacements generated with a commercial treatment planning system. And verification films were used to measure two-dimensional dose distributions. Then a computerized dose comparison system will be introduced to analyze the dose deviations. Materials/methods: We assumed MLC positional inaccuracy from 0 to 6 mm for step-and-shoot IMRT in clinical cases by simulating the different leaf displacements with a commercial treatment planning system. Then we transferred the treatment plans with different leaf offset that may be happened in clinical situation to linear accelerator. Verification films (Kodat EDR2) were well positioned within solid water phantoms to be irradiated by the simulated plans. The films were scanned to display two-dimensional dose distributions. Finally, we compared with the dose distributions with MLC positional inaccuracy by a two-dimensional dose comparison software to analyze the deviations in Gamma indexes and normalized agreement test (NAT) values. Results: In general, the data show that larger leaf positional error induces larger dose error. More fields used for treatment generate lesser errors. Besides, leaf position relative to a field influences the degree of dose error. A leaf lying close to the border of a field leads to a more significant dose deviation than a leaf in the center. Algorithms for intensity modulation also affect

The probability distribution of extreme precipitation

Science.gov (United States)

Korolev, V. Yu.; Gorshenin, A. K.

2017-12-01

On the basis of the negative binomial distribution of the duration of wet periods calculated per day, an asymptotic model is proposed for distributing the maximum daily rainfall volume during the wet period, having the form of a mixture of Frechet distributions and coinciding with the distribution of the positive degree of a random variable having the Fisher-Snedecor distribution. The method of proving the corresponding result is based on limit theorems for extreme order statistics in samples of a random volume with a mixed Poisson distribution. The adequacy of the models proposed and methods of their statistical analysis is demonstrated by the example of estimating the extreme distribution parameters based on real data.

Source distribution dependent scatter correction for PVI

International Nuclear Information System (INIS)

Barney, J.S.; Harrop, R.; Dykstra, C.J.

1993-01-01

Source distribution dependent scatter correction methods which incorporate different amounts of information about the source position and material distribution have been developed and tested. The techniques use image to projection integral transformation incorporating varying degrees of information on the distribution of scattering material, or convolution subtraction methods, with some information about the scattering material included in one of the convolution methods. To test the techniques, the authors apply them to data generated by Monte Carlo simulations which use geometric shapes or a voxelized density map to model the scattering material. Source position and material distribution have been found to have some effect on scatter correction. An image to projection method which incorporates a density map produces accurate scatter correction but is computationally expensive. Simpler methods, both image to projection and convolution, can also provide effective scatter correction

DISTRIBUTION OF TWO-PHASE FLOW IN A DISTRIBUTOR

Directory of Open Access Journals (Sweden)

AZRIDJAL AZIZ

2012-02-01

Full Text Available The flow configuration and distribution behavior of two-phase flow in a distributor made of acrylic resin have been investigated experimentally. In this study, air and water were used as two-phase flow working fluids. The distributor consists of one inlet and two outlets, which are set as upper and lower, respectively. The flow visualization at the distributor was made by using a high–speed camera. The flow rates of air and water flowing out from the upper and lower outlet branches were measured. Effects of inclination angle of the distributor were investigated. By changing the inclination angle from vertical to horizontal, uneven distributions were also observed. The distribution of two-phase flow through distributor tends even flow distribution on the vertical position and tends uneven distribution on inclined and horizontal positions. It is shown that even distribution could be achieved at high superficial velocities of both air and water.

Li distribution characterization in Li-ion batteries positive electrodes containing LixNi0.8Co0.15Al0.05O2 secondary particles (0.75 ⩽ x ⩽ 1.0)

International Nuclear Information System (INIS)

Mima, K.; Gonzalez-Arrabal, R.; Azuma, H.; Yamazaki, A.; Okuda, C.; Ukyo, Y.; Sawada, H.; Fujita, K.; Kato, Y.; Perlado, J.M.; Nakai, S.

2012-01-01

The elemental distribution of as-received (non-charged) and charged Li-ion battery positive electrodes containing Li x Ni 0.8 Co 0.15 Al 0.05 O 2 (0.75 ⩽ x ⩽ 1.0) microparticles as active material is characterized by combining μ-PIXE and μ-PIGE techniques. PIGE measurements evidence that the Li distribution is inhomogeneous (existence of Li-rich and Li-depleted regions) in as-received electrodes corresponding with the distribution of secondary particles but it is homogeneous within the studied individual secondary micro-particles. The dependence of the Li distribution on electrode thickness and on charging conditions is characterized by measuring the Li distribution maps in specifically fabricated cross-sectional samples. These data show that decreasing the electrode thickness down to 35 μm and charging the batteries at slow rate give rise to more homogeneous Li depth profiles.

Optimization of turbine positioning in water distribution networks. A Sicilian case study

Science.gov (United States)

Milici, Barbara; Messineo, Simona; Messineo, Antonio

2017-11-01

The potential energy of water in Water Distribution Networks (WDNs), is usually dissipated by Pressure Reduction Valves (PRVs), thanks to which water utilities manage the pressure level in selected nodes of the network. The present study explores the use of economic hydraulic machines, pumps as turbines (PATs), to produce energy in a small network with the aim to avoid dissipation in favour of renewable energy production. The proposed study is applied to a WDN located in a town close to Palermo (Sicily), where users often install private tanks, to collect water during the period of water scarcity conditions. As expected, the economic benefit of PATs installation in WDNs is affected by the presence of private tanks, whose presence deeply modifies the network from designed condition. The analysis is carried out by means of a mathematical model, which is able to simulate dynamically water distribution networks with private tanks and PATs. As expected, the advantage of PATs' installation in terms of renewable energy recovery is strictly conditioned by their placement in the WDN.

Incidence of centrally positioned nuclei in mouse masticatory muscle fibers

DEFF Research Database (Denmark)

Vilmann, A; Vilmann, H; Kirkeby, S

1989-01-01

Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei in...

$xy$ Position Reconstruction in DarkSide-50

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Jason Philip [Princeton Univ., NJ (United States)

2015-01-01

The DarkSide-50 experiment seeks to directly detect dark matter in a liquid argon time projection chamber. In this dissertation, I present an algorithm of my design that determines the position of particle interactions with the liquid argon. This position reconstruction algorithm will be used by DarkSide-50 to reject backgrounds, particularly backgrounds from radioactive elements on the detector surface. The position reconstruction algorithm functions by constructing light response functions (LRFs) that map locations in the detector to the expected distribution of signal in DarkSide-50's 38 photomultiplier tubes. Accurate LRFs cannot be produced by simulations of DarkSide-50's optics because such simulations are known to be awed. Instead, this algorithm constructs LRFs using an iterative process driven by data. Initial, awed LRFs are produced using simulated events but then used to produce new LRFs from data events. Multiple generations of LRFs are created from data with each generation driven to better satisfy a known feature of the detector: the dominant argon-39 background is uniformly distributed. I also discuss a method of discriminating against surface background as an alternative to the common approach of ducialization. This method considers the di erence in goodnessof- t between the best- t reconstructed position and the best- t position at the detector's surface. I conclude by presenting results on the performance and validity of this algorithm, including some discussion of reconstruction errors.

Relationship between Trust, Distributed Leadership and Job Performance in Health Care Context

DEFF Research Database (Denmark)

Jain, Ajay K.; Günzel-Jensen, Franziska

2014-01-01

satisfaction mediates the relationship between vertical trust and distributed leadership, and further distributed leadership had a positive impact on job performance. Furthermore, the results also showed that job satisfaction had a positively significant impact on distributed leadership and employees......´ performance. Moreover, distributed leadership has affected employees´ performance positively and it carries the impact of job satisfaction on performance. Implications: The study showed that trust and job satisfaction are important triggers of DL. Furthermore, results are also interesting because literature......Purpose: This study aims at investigating the effect of vertical trust on distributed leadership and performance as mediated by job satisfaction, and further to see the role of DL in carrying out the effect of satisfaction on employees´ performance. Design: Grounded in literature on organizational...

A position sensitive parallel plate avalanche counter

International Nuclear Information System (INIS)

Lombardi, M.; Tan Jilian; Potenza, R.; D'amico, V.

1986-01-01

A position sensitive parallel plate avalanche counter with a distributed constant delay-line-cathode (PSAC) is described. The strips formed on the printed board were served as the cathode and the delay line for readout of signals. The detector (PSAC) was operated in isobutane gas at the pressure range from 10 to 20 torr. The position resolution is better than 1 mm and the time resolution is about 350 ps, for 252 Cf fission-spectrum source

Distribution characteristics of stock market liquidity

Science.gov (United States)

Luo, Jiawen; Chen, Langnan; Liu, Hao

2013-12-01

We examine the distribution characteristics of stock market liquidity by employing the generalized additive models for location, scale and shape (GAMLSS) model and three-minute frequency data from Chinese stock markets. We find that the BCPE distribution within the GAMLSS framework fits the distributions of stock market liquidity well with the diagnosis test. We also find that the stock market index exhibits a significant impact on the distributions of stock market liquidity. The stock market liquidity usually exhibits a positive skewness, but a normal distribution at a low level of stock market index and a high-peak and fat-tail shape at a high level of stock market index.

Fourier-transform spectroscopy and coupled-channels deperturbation treatment of the A1Σ+-b3Π complex of KCs

Science.gov (United States)

Kruzins, A.; Klincare, I.; Nikolayeva, O.; Tamanis, M.; Ferber, R.; Pazyuk, E. A.; Stolyarov, A. V.

2010-04-01

The laser-induced fluorescence (LIF) A1Σ+-b3Π→X1Σ+ spectra of the KCs molecule were recorded in a near infrared region by a Fourier-transform spectrometer with a resolution of 0.03 cm-1. Overall more than 200 collisionally enhanced LIF spectra were rotationally assigned to K39Cs133 and K41Cs133 isotopomers yielding more than 3400 rovibronic term values of the strongly mixed singlet A1Σ+ and triplet b3Π states with the uncertainty of 0.003-0.01 cm-1. Experimental data massive starts from the lowest vibrational level vA=0 of the singlet and nonuniformly covers the energy range E∈[10040,13250] cm-1 with rotational quantum numbers J'∈[7,225]. Besides the dominating regular A1Σ+-b3ΠΩ=0 interactions, the weak local heterogeneous A1Σ+-b3ΠΩ=1 perturbations have been discovered and analyzed. Coupled-channels deperturbation analysis of the experimental K39Cs133 e-parity term values of the A1Σ+-b3ΠΩ=0,1,2 complex was accomplished in the framework of the phenomenological 4×4 Hamiltonian accounting implicitly for regular interactions with the remote 1Π and 3Σ+ states. The diabatic potential energy curves of the A1Σ+ and b3Π states, as well as relevant spin-orbit coupling matrix elements, were defined analytically with the expanded Morse oscillators model. The obtained parameters reproduce 95% of experimental data field of the K39Cs133 isotopomer with a standard deviation of 0.004 cm-1, which is consistent with the uncertainty of the experiment. Reliability of the derived parameters was confirmed by a good agreement between the predicted and experimental term values of the K41Cs133 isotopomer. The calculated relative intensity distributions in A-b→X LIF progressions are also consistent with their experimental counterparts. The deperturbation model was applied for simulation of a pump-dump optical cycle a3Σ+→A1Σ+-b3Π→X1Σ+ proposed for transformation of ultracold KCs molecules to their absolute ground state vX=0;JX=0.

Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae.

Science.gov (United States)

de Waal, C; Rodger, J G; Anderson, B; Ellis, A G

2014-05-01

Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Submicron position-sensitive detector

Energy Technology Data Exchange (ETDEWEB)

Pugatch, V M; Rosenfeld, A B; Litovchenko, P G; Barabash, L I; Nemets, O F; Pavlenko, Yu N; Vasiliev, Yu O [Ukrainian Academy of Sciences, Kiev (Ukraine). Inst. for Nuclear Research

1992-08-01

A method has been developed to measure precisely the coordinates of charged particles incident between adjacent strips of a strip detector. The position sensitivity of an inter-strip gap has been studied by means of a pulsed laser beam and irradiation by [alpha]-particles of a [sup 226]Ra-source. The capacitive division of charge generated by the incident particle depends on the position of its track. Its coordinates were determined by two-dimensional amplitude analysis of the charges collected by neighbouring strips. This method of coordinate determination applied to studies of spatial and energy distributions of electromagnetic as well as charged particle beams (including radioactive ion beams) of low intensity could provide the highest level of the precision limited by the track dimensions of charged particles, i.e. percents of a micrometer. (orig.).

Leaf position optimization for step-and-shoot IMRT

International Nuclear Information System (INIS)

Gersem, Werner de; Claus, Filip; Wagter, Carlos de; Duyse, Bart van; Neve, Wilfried de

2001-01-01

Purpose: To describe the theoretical basis, the algorithm, and implementation of a tool that optimizes segment shapes and weights for step-and-shoot intensity-modulated radiation therapy delivered by multileaf collimators. Methods and Materials: The tool, called SOWAT (Segment Outline and Weight Adapting Tool) is applied to a set of segments, segment weights, and corresponding dose distribution, computed by an external dose computation engine. SOWAT evaluates the effects of changing the position of each collimating leaf of each segment on an objective function, as follows. Changing a leaf position causes a change in the segment-specific dose matrix, which is calculated by a fast dose computation algorithm. A weighted sum of all segment-specific dose matrices provides the dose distribution and allows computation of the value of the objective function. Only leaf position changes that comply with the multileaf collimator constraints are evaluated. Leaf position changes that tend to decrease the value of the objective function are retained. After several possible positions have been evaluated for all collimating leaves of all segments, an external dose engine recomputes the dose distribution, based on the adapted leaf positions and weights. The plan is evaluated. If the plan is accepted, a segment sequencer is used to make the prescription files for the treatment machine. Otherwise, the user can restart SOWAT using the new set of segments, segment weights, and corresponding dose distribution. The implementation was illustrated using two example cases. The first example is a T1N0M0 supraglottic cancer case that was distributed as a multicenter planning exercise by investigators from Rotterdam, The Netherlands. The exercise involved a two-phase plan. Phase 1 involved the delivery of 46 Gy to a concave-shaped planning target volume (PTV) consisting of the primary tumor volume and the elective lymph nodal regions II-IV on both sides of the neck. Phase 2 involved a boost of

Influence of patient position and implant material on the stress distribution in an artificial intervertebral disc of the lumbar vertebrae

Directory of Open Access Journals (Sweden)

Karpiński Robert

2017-01-01

Full Text Available The aim of this paper was to determine the effect of using cobalt and titanium-based alloys as implant materials for the lumbar vertebrae with an artificial intervertebral disc on the stress distribution. The lumbar vertebrae were chosen for the study because they carry considerably higher loads, especially while standing or sitting. Finite element method (FEM simulations were conducted for three standard loads reflecting three patient's positions: recumbent, standing and sitting. The FEM analysis was performed using the SolidWorks Simulation module. Artificial units containing a pair of vertebrae with a prosthesis between them were designed by the Solid Edge software, based on micro-computed tomography CT scans of the patient's spine. The implant model was designed with its shape based on the geometry of surrounding vertebrae, consisting of an upper pad, a bottom pad and an insert (intervertebral disc. Two implant material configurations were studied. One involved the use of titanium alloy for the upper and bottom pads, while in the other, these pads were made of cobalt alloy. In both cases, a polyethylene insert was used. The FEM results demonstrate that both material configurations meet the requirements for prosthesis design. In both material configurations, the maximum stresses in each prosthesis element are almost twice higher in a sitting posture than in a recumbent position.

The adder (Vipera berus in Southern Altay Mountains: population characteristics, distribution, morphology and phylogenetic position

Directory of Open Access Journals (Sweden)

Shaopeng Cui

2016-08-01

Full Text Available As the most widely distributed snake in Eurasia, the adder (Vipera berus has been extensively investigated in Europe but poorly understood in Asia. The Southern Altay Mountains represent the adder’s southern distribution limit in Central Asia, whereas its population status has never been assessed. We conducted, for the first time, field surveys for the adder at two areas of Southern Altay Mountains using a combination of line transects and random searches. We also described the morphological characteristics of the collected specimens and conducted analyses of external morphology and molecular phylogeny. The results showed that the adder distributed in both survey sites and we recorded a total of 34 sightings. In Kanas river valley, the estimated encounter rate over a total of 137 km transects was 0.15 ± 0.05 sightings/km. The occurrence of melanism was only 17%. The small size was typical for the adders in Southern Altay Mountains in contrast to other geographic populations of the nominate subspecies. A phylogenetic tree obtained by Bayesian Inference based on DNA sequences of the mitochondrial cytochrome b (1,023 bp grouped them within the Northern clade of the species but failed to separate them from the subspecies V. b. sachalinensis. Our discovery extends the distribution range of V. berus and provides a basis for further researches. We discuss the hypothesis that the adder expands its distribution border to the southwest along the mountains’ elevation gradient, but the population abundance declines gradually due to a drying climate.

Students’ strategies for position-taking in transnational education

DEFF Research Database (Denmark)

Li, Jin Hui

2016-01-01

as a field of struggle. The article discusses in depth how different student positions are led by the dispositions of having a certain nationality combined with international experiences/travel mobility. It will furthermore also discuss how the dispositions of national academic capital are related......The article illuminates the positions distributed and the strategies for position-taking which students pursue in order to transform or preserve their positions in a classroom with a transnational context where students have different national and international education experiences. Furthermore......, how their positions are related to their aspirations for the future will be elucidated. Based on interviews with Danish and Chinese students enrolled at a Sino-Danish university situated in Beijing, the article identifies four different navigation strategies for position-taking in such a classroom...

Power distribution forecasting device for reactors

International Nuclear Information System (INIS)

Tsukii, Makoto

1981-01-01

Purpose: To save expensive calculations on the forecasting of reactor power distribution. Constitution: Core status (CSD) such as entire coolant flow rate, pressures in the reactor, temperatures at the outlet and inlet and positions for control rods are inputted into a power distribution calculation device to calculate the power distribution based on physical models intermittently. Further, present power distribution is calculated based on in-core neutron flux measured values and CSD in a process control computer. Further, the ratio of the calculation results of the latter to those of the former is calculated, stored and inputted into a correction device to correct the forecast power distribution obtained by the power distribution calculation device. This enables to forecast the power distribution with excellent responsivity in the reactor site. (Furukawa, Y.)

Radiation distribution sensing with normal optical fiber

International Nuclear Information System (INIS)

Kawarabayashi, Jun; Mizuno, Ryoji; Naka, Ryotaro; Uritani, Akira; Watanabe, Ken-ichi; Iguchi, Tetsuo; Tsujimura, Norio

2002-01-01

The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ( 90 Sr -90 Y), gamma rays ( 137 Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10 -5 % and 5.4x10 -4 %, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that the radiation distributions were calculated from the spectrum by mathematical deconvolution technique. (author)

Isotopologue signatures of nitrous oxide produced by nitrate-ammonifying bacteria isolated from soil

Science.gov (United States)

Behrendt, Undine; Well, Reinhard; Giesemann, Anette; Ulrich, Andreas; Augustin, Jürgen

2015-04-01

Agricultural soils are the largest single source of anthropogenic N2O to the atmosphere, primarily driven by microbiological processes such as denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Both processes occur under similar conditions of low oxygen concentration and therefore, source partitioning of emitted N2O is difficult. Understanding what controls the dynamics and reaction equilibrium of denitrification and DNRA is important and may allow the development of more effective mitigation strategies. 15N site preference (SP), i.e. the difference between 15N of the central and peripheral N-position of the asymmetric N2O molecule, differs depending on processes involved in N2O formation. Hence investigation of the isotopomer ratios of formed N2O potentially presents a reliable mean to identify its source. In this study, bacterial isolates obtained from organic soils were screened for their ability to reduce nitrate/nitrite to ammonium and to release N2O to the atmosphere. Taxonomic characterisation of the strains revealed that N2O formation was only detected in ammonifying strains affiliated to several genera of the family Enterobacteriaceae and strains belonging to the genus Bacillus and Paenibacillus. Sampling of N2O was conducted by incubation of strains under oxic and anoxic conditions. Investigation of the 15N site preference showed SP values in the range of 39 to 57 o . Incubation conditions had no influence on the SP. The lowest values were achieved by a strain of the species Escherichia coli which was included in this study as a DNRA reference bacterium harbouring the NrfA gene that is coding the nitrite reductase, associated with respiratory nitrite ammonification. Soil isolates showed SP-values higher than 40 o . Comparison of these results with SP-values of N2O produced by denitrifying bacteria in pure cultures (-5 to 0 o )^[1, 2]revealedsignificantdifferences.Incontrast,N_2OproducedbydenitrifyingfungidisplayedSP - valuesinarangeof

Ultrasonographic examination of plantar fasciitis: a comparison of patient positions during examination.

Science.gov (United States)

Ahn, Jae Hoon; Lee, Choong Woo; Park, ChanJoo; Kim, Yoon-Chung

2016-01-01

Musculoskeletal ultrasound is a non-invasive and low-cost modality for real-time visualisation of the plantar fascia. Ultrasound examination for plantar fasciitis is generally performed with the patient in a prone position, although the rational for using a prone position has not been validated. The aim of the study was to investigate if ultrasound examination in a supine position, which is more comfortable than the prone position, is valid. We conducted a prospective study of 30 participants with plantar fasciitis, 8 men (27 %) and 22 women (73 %), with a mean age of 53.9 ± 12.6 (range, 32 to 77) years, and an equal distribution of left and right feet. The plantar heel was divided into three portions for ultrasound examination: medial, central and lateral. Two measurements of plantar fascia thickness were obtained for each portion, with participants in 2 positions (supine and prone) and for 2 ankle postures (neutral and 15° of plantarflexion). Mean measurements of plantar fascia thickness were compared between the two positions (Wilcoxon signed rank tests for non-normally distributed data and paired t-tests for normally distributed data). Participants were asked to report their preferred position for examination, supine or prone. The measured thickness was comparable for both supine and prone positions, for both ankle postures, neutral and 15° of plantarflexion (p > 0.05). A specific self-reported preferred position was not identified. Ultrasound examination of plantar fasciitis can be performed in the supine position without any significant difference in measurement compared to examination in the conventional prone position. The Catholic Medical Center Office of Human Research Protection Program (CMC-OHRP)/Institutional Review Board approved the current study (Approval No. KC12DISI0338), and all participants provided their written informed consent for participation and publication.

Magnetized retarding field energy analyzer measuring the particle flux and ion energy distribution of both positive and negative ions

International Nuclear Information System (INIS)

Rafalskyi, Dmytro; Aanesland, Ane; Dudin, Stanislav

2015-01-01

This paper presents the development of a magnetized retarding field energy analyzer (MRFEA) used for positive and negative ion analysis. The two-stage analyzer combines a magnetic electron barrier and an electrostatic ion energy barrier allowing both positive and negative ions to be analyzed without the influence of electrons (co-extracted or created downstream). An optimal design of the MRFEA for ion-ion beams has been achieved by a comparative study of three different MRFEA configurations, and from this, scaling laws of an optimal magnetic field strength and topology have been deduced. The optimal design consists of a uniform magnetic field barrier created in a rectangular channel and an electrostatic barrier consisting of a single grid and a collector placed behind the magnetic field. The magnetic barrier alone provides an electron suppression ratio inside the analyzer of up to 6000, while keeping the ion energy resolution below 5 eV. The effective ion transparency combining the magnetic and electrostatic sections of the MRFEA is measured as a function of the ion energy. It is found that the ion transparency of the magnetic barrier increases almost linearly with increasing ion energy in the low-energy range (below 200 eV) and saturates at high ion energies. The ion transparency of the electrostatic section is almost constant and close to the optical transparency of the entrance grid. We show here that the MRFEA can provide both accurate ion flux and ion energy distribution measurements in various experimental setups with ion beams or plasmas run at low pressure and with ion energies above 10 eV

Reflection Positive Stochastic Processes Indexed by Lie Groups

Science.gov (United States)

Jorgensen, Palle E. T.; Neeb, Karl-Hermann; Ólafsson, Gestur

2016-06-01

Reflection positivity originates from one of the Osterwalder-Schrader axioms for constructive quantum field theory. It serves as a bridge between euclidean and relativistic quantum field theory. In mathematics, more specifically, in representation theory, it is related to the Cartan duality of symmetric Lie groups (Lie groups with an involution) and results in a transformation of a unitary representation of a symmetric Lie group to a unitary representation of its Cartan dual. In this article we continue our investigation of representation theoretic aspects of reflection positivity by discussing reflection positive Markov processes indexed by Lie groups, measures on path spaces, and invariant gaussian measures in spaces of distribution vectors. This provides new constructions of reflection positive unitary representations.

Distributed leadership in health care

DEFF Research Database (Denmark)

Günzel-Jensen, Franziska; Jain, Ajay K.; Kjeldsen, Anne Mette

2018-01-01

Management and health care literature is increasingly preoccupied with leadership as a collective social process, and related leadership concepts such as distributed leadership have therefore recently gained momentum. This paper investigates how formal, i.e. transformational, transactional...... and empowering, leadership styles affect employees’ perceived agency in distributed leadership, and whether these associations are mediated by employees’ perceived organizational efficacy. Based on large-scale survey data from a study at one of Scandinavia’s largest public hospitals (N = 1,147), our results show...... that all leadership styles had a significant positive impact on employees’ perceived agency in distributed leadership. Further, organizational efficacy related negatively to employees’ perceived agency in distributed leadership; however a mediatory impact of this on the formal leadership styles...

Evaluation of the photocathode laser transverse distribution

Energy Technology Data Exchange (ETDEWEB)

Saisa-ard, Chaipattana [DESY, Zeuthen (Germany); Chiang Mai Univ., Chiang Mai (Thailand); Krasilnikov, Mikhail; Vashchenko, Grygorii [DESY, Zeuthen (Germany)

2016-07-01

Many years experience of electron source developments at the photo injector test facility at DESY in Zeuthen (PITZ) show that the photocathode laser is the one of major tools to produce high brightness electron beams. The transverse distribution of the laser on the photocathode plays a significant role in the high brightness photo injector optimization. However, the imperfections in the laser beam profile according to the deviation from a radially homogeneous profile directly result in transversely distorted charged particle distributions. This includes inhomogeneous core as well as transverse halo which is due to not sharp edges around the core. The laser transverse distribution is measured at PITZ using a virtual cathode:this is a CCD camera located at the position which is optically equivalent to the photocathode position (so called virtual cathode). An algorithm is developed for the evaluation of the experimentally obtained transverse profiles. It fits a flat-top or an inhomogeneous rotational symmetric core with exponentially decaying tails to an experimental distribution. The MATLAB script with implemented algorithm is applied to a set of measured transverse laser distributions. Results of the analysis will be presented.

Distribution of chirality in the quantum walk: Markov process and entanglement

International Nuclear Information System (INIS)

Romanelli, Alejandro

2010-01-01

The asymptotic behavior of the quantum walk on the line is investigated, focusing on the probability distribution of chirality independently of position. It is shown analytically that this distribution has a longtime limit that is stationary and depends on the initial conditions. This result is unexpected in the context of the unitary evolution of the quantum walk as it is usually linked to a Markovian process. The asymptotic value of the entanglement between the coin and the position is determined by the chirality distribution. For given asymptotic values of both the entanglement and the chirality distribution, it is possible to find the corresponding initial conditions within a particular class of spatially extended Gaussian distributions.

The tensor distribution function.

Science.gov (United States)

Leow, A D; Zhu, S; Zhan, L; McMahon, K; de Zubicaray, G I; Meredith, M; Wright, M J; Toga, A W; Thompson, P M

2009-01-01

Diffusion weighted magnetic resonance imaging is a powerful tool that can be employed to study white matter microstructure by examining the 3D displacement profile of water molecules in brain tissue. By applying diffusion-sensitized gradients along a minimum of six directions, second-order tensors (represented by three-by-three positive definite matrices) can be computed to model dominant diffusion processes. However, conventional DTI is not sufficient to resolve more complicated white matter configurations, e.g., crossing fiber tracts. Recently, a number of high-angular resolution schemes with more than six gradient directions have been employed to address this issue. In this article, we introduce the tensor distribution function (TDF), a probability function defined on the space of symmetric positive definite matrices. Using the calculus of variations, we solve the TDF that optimally describes the observed data. Here, fiber crossing is modeled as an ensemble of Gaussian diffusion processes with weights specified by the TDF. Once this optimal TDF is determined, the orientation distribution function (ODF) can easily be computed by analytic integration of the resulting displacement probability function. Moreover, a tensor orientation distribution function (TOD) may also be derived from the TDF, allowing for the estimation of principal fiber directions and their corresponding eigenvalues.

Dynamical parton distributions of the nucleon and very small-x physics

International Nuclear Information System (INIS)

Glueck, M.; Jimenez-Delgado, P.; Reya, E.

2008-01-01

Utilizing recent DIS measurements (F 2,L ) and data on dilepton and high-E T jet production we determine the dynamical parton distributions of the nucleon generated radiatively from valence-like positive input distributions at optimally chosen low resolution scales. These are compared with 'standard' distributions generated from positive input distributions at some fixed and higher resolution scale. It is shown that up to the next-to-leading order NLO(MS, DIS) of perturbative QCD considered in this paper, the uncertainties of the dynamical distributions are, as expected, smaller than those of their standard counterparts. This holds true in particular in the presently unexplored extremely small-x region relevant for evaluating ultrahigh energy cross sections in astrophysical applications. It is noted that our new dynamical distributions are compatible, within the presently determined uncertainties, with previously determined dynamical parton distributions. (orig.)

Implementation of a Wireless Time Distribution Testbed Protected with Quantum Key Distribution

Energy Technology Data Exchange (ETDEWEB)

Bonior, Jason D [ORNL; Evans, Philip G [ORNL; Sheets, Gregory S [ORNL; Jones, John P [ORNL; Flynn, Toby H [ORNL; O' Neil, Lori Ross [Pacific Northwest National Laboratory (PNNL); Hutton, William [Pacific Northwest National Laboratory (PNNL); Pratt, Richard [Pacific Northwest National Laboratory (PNNL); Carroll, Thomas E. [Pacific Northwest National Laboratory (PNNL)

2017-01-01

Secure time transfer is critical for many timesensitive applications. the Global Positioning System (GPS) which is often used for this purpose has been shown to be susceptible to spoofing attacks. Quantum Key Distribution offers a way to securely generate encryption keys at two locations. Through careful use of this information it is possible to create a system that is more resistant to spoofing attacks. In this paper we describe our work to create a testbed which utilizes QKD and traditional RF links. This testbed will be used for the development of more secure and spoofing resistant time distribution protocols.

The design of a position-sensitive thermal-neutron detector

International Nuclear Information System (INIS)

Zhang Yi; Chen Ziyu; Shen Ji

2007-01-01

We design a type of position-sensitive thermal-neutron detector. The design is based on the nuclear reaction 10 B(n, α) 7 Li, and solid boron-10 is used as the target material while the alpha and lithium-7 particles from the reaction are caught as the source of position information of the original neutrons. With the help of MCNP software, we simulate the distribution of alpha particles in the boron target, which leads to the optimal thickness of target, physical efficiency and position resolution. (authors)

Embryonic and foetal Islet-1 positive cells in human hearts are also positive to c-Kit

Directory of Open Access Journals (Sweden)

C. Serradifalco

2011-12-01

Full Text Available During embryogenesis, the mammalian heart develops from a primitive heart tube originating from two bilateral primary heart fields located in the lateral plate mesoderm. Cells belongings to the pre-cardiac mesoderm will differentiate into early cardiac progenitors, which express early transcription factors which are also common to the Isl-1 positive cardiac progenitor cells isolated from the developing pharyngeal mesoderm and the foetal and post-natal mice hearts. A second population of cardiac progenitor cells positive to c-Kit has been abundantly isolated from adult hearts. Until now, these two populations have been considered two different sets of progenitor cells present in the heart in different stages of an individual life. In the present study we collected embryonic, foetal and infant hearts, and we tested the hypotheses that c-Kit positive cells, usually isolated from the adult heart, are also present in the intra-uterine life and persist in the adult heart after birth, and that foetal Isl-1 positive cells are also positive to c-Kit. Using immunohistochemistry we studied the temporal distribution of Isl-1 positive and c-Kit/CD105 double positive cells, and by immunofluorescence and confocal analysis we studied the co-localization of c-Kit and Isl-1 positive cells. The results indicated that cardiomyocytes and interstitial cells were positive for c-Kit from the 9th to the 19th gestational week, that cells positive for both c-Kit and CD105 appeared in the interstitium at the 17th gestational week and persisted in the postnatal age, and that the Isl-1 positive cells were a subset of the c-Kit positive population.

Signal processing for distributed readout using TESs

International Nuclear Information System (INIS)

Smith, Stephen J.; Whitford, Chris H.; Fraser, George W.

2006-01-01

We describe optimal filtering algorithms for determining energy and position resolution in position-sensitive Transition Edge Sensor (TES) Distributed Read-Out Imaging Devices (DROIDs). Improved algorithms, developed using a small-signal finite-element model, are based on least-squares minimisation of the total noise power in the correlated dual TES DROID. Through numerical simulations we show that significant improvements in energy and position resolution are theoretically possible over existing methods

A new HBMO algorithm for multiobjective daily Volt/Var control in distribution systems considering Distributed Generators

Energy Technology Data Exchange (ETDEWEB)

Niknam, Taher [Electrical and Electronics Engineering Department, Shiraz University of Technology, Modars Blvd. P.O. 71555-313, Shiraz (Iran, Islamic Republic of)

2011-03-15

In recent years, Distributed Generators (DGs) connected to the distribution network have received increasing attention. The connection of enormous DGs into existing distribution network changes the operation of distribution systems. Because of the small X/R ratio and radial structure of distribution systems, DGs affect the daily Volt/Var control. This paper presents a new algorithm for multiobjective daily Volt/Var control in distribution systems including Distributed Generators (DGs). The objectives are costs of energy generation by DGs and distribution companies, electrical energy losses and the voltage deviations for the next day. A new optimization algorithm based on a Chaotic Improved Honey Bee Mating Optimization (CIHBMO) is proposed to determine the active power values of DGs, reactive power values of capacitors and tap positions of transformers for the next day. Since objectives are not the same, a fuzzy system is used to calculate the best solution. The plausibility of the proposed algorithm is demonstrated and its performance is compared with other methods on a 69-bus distribution feeder. Simulation results illustrate that the proposed algorithm has better outperforms the other algorithms. (author)

A new HBMO algorithm for multiobjective daily Volt/Var control in distribution systems considering Distributed Generators

International Nuclear Information System (INIS)

Niknam, Taher

2011-01-01

In recent years, Distributed Generators (DGs) connected to the distribution network have received increasing attention. The connection of enormous DGs into existing distribution network changes the operation of distribution systems. Because of the small X/R ratio and radial structure of distribution systems, DGs affect the daily Volt/Var control. This paper presents a new algorithm for multiobjective daily Volt/Var control in distribution systems including Distributed Generators (DGs). The objectives are costs of energy generation by DGs and distribution companies, electrical energy losses and the voltage deviations for the next day. A new optimization algorithm based on a Chaotic Improved Honey Bee Mating Optimization (CIHBMO) is proposed to determine the active power values of DGs, reactive power values of capacitors and tap positions of transformers for the next day. Since objectives are not the same, a fuzzy system is used to calculate the best solution. The plausibility of the proposed algorithm is demonstrated and its performance is compared with other methods on a 69-bus distribution feeder. Simulation results illustrate that the proposed algorithm has better outperforms the other algorithms.

Distributed morality in an information society.

Science.gov (United States)

Floridi, Luciano

2013-09-01

The phenomenon of distributed knowledge is well-known in epistemic logic. In this paper, a similar phenomenon in ethics, somewhat neglected so far, is investigated, namely distributed morality. The article explains the nature of distributed morality, as a feature of moral agency, and explores the implications of its occurrence in advanced information societies. In the course of the analysis, the concept of infraethics is introduced, in order to refer to the ensemble of moral enablers, which, although morally neutral per se, can significantly facilitate or hinder both positive and negative moral behaviours.

Mass balance, meteorology, area altitude distribution, glacier-surface altitude, ice motion, terminus position, and runoff at Gulkana Glacier, Alaska, 1996 balance year

Science.gov (United States)

March, Rod S.

2003-01-01

The 1996 measured winter snow, maximum winter snow, net, and annual balances in the Gulkana Glacier Basin were evaluated on the basis of meteorological, hydrological, and glaciological data. Averaged over the glacier, the measured winter snow balance was 0.87 meter on April 18, 1996, 1.1 standard deviation below the long-term average; the maximum winter snow balance, 1.06 meters, was reached on May 28, 1996; and the net balance (from August 30, 1995, to August 24, 1996) was -0.53 meter, 0.53 standard deviation below the long-term average. The annual balance (October 1, 1995, to September 30, 1996) was -0.37 meter. Area-averaged balances were reported using both the 1967 and 1993 area altitude distributions (the numbers previously given in this abstract use the 1993 area altitude distribution). Net balance was about 25 percent less negative using the 1993 area altitude distribution than the 1967 distribution. Annual average air temperature was 0.9 degree Celsius warmer than that recorded with the analog sensor used since 1966. Total precipitation catch for the year was 0.78 meter, 0.8 standard deviations below normal. The annual average wind speed was 3.5 meters per second in the first year of measuring wind speed. Annual runoff averaged 1.50 meters over the basin, 1.0 standard deviation below the long-term average. Glacier-surface altitude and ice-motion changes measured at three index sites document seasonal ice-speed and glacier-thickness changes. Both showed a continuation of a slowing and thinning trend present in the 1990s. The glacier terminus and lower ablation area were defined for 1996 with a handheld Global Positioning System survey of 126 locations spread out over about 4 kilometers on the lower glacier margin. From 1949 to 1996, the terminus retreated about 1,650 meters for an average retreat rate of 35 meters per year.

Occurrence and distribution of Indian primates

Science.gov (United States)

Karanth, K.K.; Nichols, J.D.; Hines, J.E.

2010-01-01

Global and regional species conservation efforts are hindered by poor distribution data and range maps. Many Indian primates face extinction, but assessments of population status are hindered by lack of reliable distribution data. We estimated the current occurrence and distribution of 15 Indian primates by applying occupancy models to field data from a country-wide survey of local experts. We modeled species occurrence in relation to ecological and social covariates (protected areas, landscape characteristics, and human influences), which we believe are critical to determining species occurrence in India. We found evidence that protected areas positively influence occurrence of seven species and for some species are their only refuge. We found evergreen forests to be more critical for some primates along with temperate and deciduous forests. Elevation negatively influenced occurrence of three species. Lower human population density was positively associated with occurrence of five species, and higher cultural tolerance was positively associated with occurrence of three species. We find that 11 primates occupy less than 15% of the total land area of India. Vulnerable primates with restricted ranges are Golden langur, Arunachal macaque, Pig-tailed macaque, stump-tailed macaque, Phayre's leaf monkey, Nilgiri langur and Lion-tailed macaque. Only Hanuman langur and rhesus macaque are widely distributed. We find occupancy modeling to be useful in determining species ranges, and in agreement with current species ranking and IUCN status. In landscapes where monitoring efforts require optimizing cost, effort and time, we used ecological and social covariates to reliably estimate species occurrence and focus species conservation efforts. ?? Elsevier Ltd.

Radiation distribution sensing with normal optical fiber

Energy Technology Data Exchange (ETDEWEB)

Kawarabayashi, Jun; Mizuno, Ryoji; Naka, Ryotaro; Uritani, Akira; Watanabe, Ken-ichi; Iguchi, Tetsuo [Nagoya Univ., Dept. of Nuclear Engineering, Nagoya, Aichi (Japan); Tsujimura, Norio [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan)

2002-12-01

The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ({sup 90}Sr{sup -90}Y), gamma rays ({sup 137}Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10{sup -5}% and 5.4x10{sup -4}%, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that the radiation distributions were calculated from the spectrum by mathematical deconvolution technique. (author)

Autonomous Positioning Techniques Based on Cramér-Rao Lower Bound Analysis

Directory of Open Access Journals (Sweden)

Urruela Andreu

2006-01-01

Full Text Available We consider the problem of autonomously locating a number of asynchronous sensor nodes in a wireless network. A strong focus lies on reducing the processing resources needed to solve the relative positioning problem, an issue of great interest in resource-constrained wireless sensor networks. In the first part of the paper, based on a well-known derivation of the Cramér-Rao lower bound for the asynchronous sensor positioning problem, we are able to construct optimal preprocessing methods for sensor clock-offset cancellation. A cancellation of unknown clock-offsets from the asynchronous positioning problem reduces processing requirements, and, under certain reasonable assumptions, allows for statistically efficient distributed positioning algorithms. Cramér-Rao lower bound theory may also be used for estimating the performance of a positioning algorithm. In the second part of this paper, we exploit this property in developing a distributed algorithm, where the global positioning problem is solved suboptimally, using a divide-and-conquer approach of low complexity. The performance of this suboptimal algorithm is evaluated through computer simulation, and compared to previously published algorithms.

Gravity-dependent ventilation distribution in rats measured with electrical impedance tomography

International Nuclear Information System (INIS)

Rooney, Daniel; Fraser, John F; R Dunster, Kimble; Schibler, Andreas; Friese, Marlies

2009-01-01

Ventilation in larger animals and humans is gravity dependent and mainly distributed to the dependent lung. Little is known of the effect of gravity on ventilation distribution in small animals such as rodents. The aim of this study was to investigate gravity-dependent ventilation distribution and regional filling characteristics in rats. Ventilation distribution and regional lung filling were measured in six rats using electrical impedance tomography (EIT). Measurements were performed in four body positions (supine, prone, left and right lateral), and all animals were ventilated with increasing tidal volumes from 3 to 8 mL kg −1 . The effect of gravity on regional ventilation distribution was assessed with profiles of relative impedance change and calculation of the geometric centre. Regional filling was measured by calculating the slope of the plot of regional versus global relative impedance change on a breath-by-breath basis. Ventilation was significantly distributed to the non-dependent lung regardless of body position and tidal volume used. The geometric centre was located in the dependent lung in all but prone position. The regional filling characteristics followed an anatomical pattern with the posterior and the right lung generally filling faster. Gravity had little impact on regional filling. Ventilation distribution in rats is gravity dependent, whereas regional filling characteristics are dependent on anatomy

A Characterization of Rectangular Distributions

OpenAIRE

Terrell, George R.

1983-01-01

It is well known that the smaller and the larger of a random sample of size two are positively correlated. The coefficient of correlation is at most one-half, and the upper bound is attained only for rectangular distributions.

Angle-resolved ion TOF spectrometer with a position sensitive detector

Energy Technology Data Exchange (ETDEWEB)

Saito, Norio [Electrotechnical Lab., Tsukuba, Ibaraki (Japan); Heiser, F; Wieliczec, K; Becker, U

1996-07-01

A angle-resolved ion time-of-flight mass spectrometer with a position sensitive anode has been investigated. Performance of this spectrometer has been demonstrated by measuring an angular distribution of a fragment ion pair, C{sup +} + O{sup +}, from CO at the photon energy of 287.4 eV. The obtained angular distribution is very close to the theoretically expected one. (author)

Net positive energy buildings

International Nuclear Information System (INIS)

Romero, A.; Barreiro, E.; Sanchez Zabala, V.

2010-01-01

Buildings are great consumers of energy, being responsible for almost 36% of CO2 emissions in Europe. Though there are many initiatives towards the reduction of energy consumption and CO2 emissions in buildings, many of the alternatives are diminished due to a lack of a unique and holistic approach to the problem. This paper reports a new innovative concept of Positive Energy Buildings (EB+), as well as an integral methodology that covers the overall design process for achieving them. The methodology evaluates energy efficiency solutions at different scales, from building site to generation systems. An educational building design in Navarra serves as a case study to check the feasibility of the proposed methodology. The study concludes that the key to achieve a Positive Energy Building is a minimized energy demand, complemented by efficient facilities and enhanced by distributed power generation from renewable sources. (Author).

Experimental and theoretical studies of the reaction of the OH radical with alkyl sulfides: 1. Direct observations of the formation of the OH-DMS adduct-pressure dependence of the forward rate of addition and development of a predictive expression at low temperature.

Science.gov (United States)

Williams, M B; Campuzano-Jost, P; Cossairt, B M; Hynes, A J; Pounds, A J

2007-01-11

A pulsed laser photolysis-pulsed laser-induced fluorescence (PLP-PLIF) system was employed to study the kinetics and mechanisms of reactions (1) OH + h6-DMS --> products and (2) OH + d6-DMS --> products. We report direct observations of the rate coefficients for the formation and dissociation of the h6-OHDMS and d6-OHDMS adducts over the pressure range 50-650 Torr and between 240 and 245 K, together with measurements of the oxygen dependence of the effective rate coefficients for reactions 1 and 2 under similar conditions. The effective rate coefficients increased as a function of O2 concentration reaching their limiting values in each case. The values of the adduct formation rate, obtained from the O2 dependencies, were in excellent agreement with values determined from direct observation of adduct equilibration in N2. OH regeneration is insignificant. The rate coefficients for the formation of the adduct isotopomers showed slight differences in their falloff behavior and do not approach the high-pressure limit in either case. The equilibrium constants obtained show no dependence on isotopomer and are in good agreement with previous work. A "second-law" analysis of the temperature dependence of the equilibrium constant gives an adduct bond strength (DeltaH degrees =-10.9 +/- 1.0 kcal mol(-1)), also in good agreement with previously reported values. Using the entropy calculated from the ab initio vibrational frequencies, we obtain a "third-law" value for the reaction enthalpy at 240 K, DeltaH(240K) degrees = -10.5 kcal mol(-1) in good agreement with the other approach. The rate coefficient for the reactions of the adducts with O2 was obtained from an analysis of the O2 dependence and was determined to be 6.3 +/- 1.2 x 10(-13) cm3 molecule(-1) s(-1), with no dependence on pressure or isotopomer. The pressure and temperature dependence for all of the elementary processes in the initial steps of the dimethylsulfide (DMS) oxidation mechanism have been characterized in

Mobile agent location in distributed environments

Science.gov (United States)

Fountoukis, S. G.; Argyropoulos, I. P.

2012-12-01

An agent is a small program acting on behalf of a user or an application which plays the role of a user. Artificial intelligence can be encapsulated in agents so that they can be capable of both behaving autonomously and showing an elementary decision ability regarding movement and some specific actions. Therefore they are often called autonomous mobile agents. In a distributed system, they can move themselves from one processing node to another through the interconnecting network infrastructure. Their purpose is to collect useful information and to carry it back to their user. Also, agents are used to start, monitor and stop processes running on the individual interconnected processing nodes of computer cluster systems. An agent has a unique id to discriminate itself from other agents and a current position. The position can be expressed as the address of the processing node which currently hosts the agent. Very often, it is necessary for a user, a processing node or another agent to know the current position of an agent in a distributed system. Several procedures and algorithms have been proposed for the purpose of position location of mobile agents. The most basic of all employs a fixed computing node, which acts as agent position repository, receiving messages from all the moving agents and keeping records of their current positions. The fixed node, responds to position queries and informs users, other nodes and other agents about the position of an agent. Herein, a model is proposed that considers pairs and triples of agents instead of single ones. A location method, which is investigated in this paper, attempts to exploit this model.

A Novel Passive Islanding Detection Scheme for Distributed Generations Based on Rate of Change of Positive Sequence Component of Voltage and Current

DEFF Research Database (Denmark)

Rostami, Ali; Jalilian, Amin; Naderi, Seyed Behzad

2017-01-01

) based wind turbine and synchronous diesel generator DGs by MATLAB/Simulink software. Different non-islanding case studies are taken into account to evaluate the effectiveness of the proposed approach. The simulation results show that the proposed method has advantage of detecting the islanding rapidly......Islanding operation is one of serious hazards of distributed generation (DG) applications. According to IEEE 1547 standard, its occurrence must be detected within two seconds. This paper presents a novel passive islanding detection method based on rate of change of positive sequence component...... of RCPSC and RCPSV exceed the predetermined threshold values, it is concluded that the islanding condition has occurred. Otherwise, it is considered as a non-islanding event. The performance of the proposed method is investigated on a sample network in the presence of doubly fed induction generator (DFIG...

Closed-loop 15N measurement of N2O and its isotopomers for real-time greenhouse gas tracing

Science.gov (United States)

Slaets, Johanna; Mayr, Leopold; Heiling, Maria; Zaman, Mohammad; Resch, Christian; Weltin, Georg; Gruber, Roman; Dercon, Gerd

2016-04-01

Quantifying sources of nitrous oxide is essential to improve understanding of the global N cycle and to develop climate-smart agriculture, as N2O has a global warming potential 300 times higher than CO2. The isotopic signature and the intramolecular distribution (site preference) of 15N are powerful tools to trace N2O, but the application of these methods is limited as conventional methods cannot provide continuous and in situ data. Here we present a method for closed-loop, real time monitoring of the N2O flux, the isotopic signature and the intramolecular distribution of 15N by using off-axis integrated cavity output spectroscopy (ICOS, Los Gatos Research). The developed method was applied to a fertilizer inhibitor experiment, in which N2O emissions were measured on undisturbed soil cores for three weeks. The treatments consisted of enriched urea-N (100 kg urea-N/ha), the same fertilizer combined with the nitrification inhibitor nitrapyrin (375 g/100 kg urea), and control cores. Monitoring the isotopic signature makes it possible to distinguish emissions from soil and fertilizer. Characterization of site preference could additionally provide a tool to identify different microbial processes leading to N2O emissions. Furthermore, the closed-loop approach enables direct measurement on site and does not require removal of CO2 and H2O. Results showed that 75% of total N2O emissions (total=11 346 μg N2O-N/m2) in the fertilized cores originated from fertilizer, while only 55% of total emissions (total=2 450 μg N2ON/m2) stemmed from fertilizer for the cores treated with nitrapyrin. In the controls, N2O derived from soil was only 40% of the size of the corresponding pool from the fertilized cores, pointing towards a priming effect on the microbial community from the fertilizer and demonstrating the bias that could be introduced by relying on non-treated cores to estimate soil emission rates, rather than using the isotopic signature. The site preference increased linearly

Positive Wigner functions render classical simulation of quantum computation efficient.

Science.gov (United States)

Mari, A; Eisert, J

2012-12-07

We show that quantum circuits where the initial state and all the following quantum operations can be represented by positive Wigner functions can be classically efficiently simulated. This is true both for continuous-variable as well as discrete variable systems in odd prime dimensions, two cases which will be treated on entirely the same footing. Noting the fact that Clifford and Gaussian operations preserve the positivity of the Wigner function, our result generalizes the Gottesman-Knill theorem. Our algorithm provides a way of sampling from the output distribution of a computation or a simulation, including the efficient sampling from an approximate output distribution in the case of sampling imperfections for initial states, gates, or measurements. In this sense, this work highlights the role of the positive Wigner function as separating classically efficiently simulable systems from those that are potentially universal for quantum computing and simulation, and it emphasizes the role of negativity of the Wigner function as a computational resource.

Optimal leaf positions for chlorophyll meter measurement in rice

Directory of Open Access Journals (Sweden)

Zhaofeng eYuan

2016-05-01

Full Text Available The Soil Plant Analysis Development (SPAD chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.. A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analysed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that positon. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status.

Effect of different breathing aids on ventilation distribution in adults with cystic fibrosis.

Directory of Open Access Journals (Sweden)

Markus Wettstein

Full Text Available BACKGROUND AND OBJECTIVES: We investigated the effect of different breathing aids on ventilation distribution in healthy adults and subjects with cystic fibrosis (CF. METHODS: In 11 healthy adults and 9 adults with CF electrical impedance tomography measurements were performed during spontaneous breathing, continuous positive airway pressure (CPAP and positive expiratory pressure (PEP therapy randomly applied in upright and lateral position. Spatial and temporal ventilation distribution was assessed. RESULTS: The proportion of ventilation directed to the dependent lung significantly increased in lateral position compared to upright in healthy and CF. This effect was enhanced with CPAP but neutralised with PEP, whereas the effect of PEP was larger in the healthy group. Temporal ventilation distribution showed exactly the opposite with homogenisation during CPAP and increased inhomogeneity with PEP. CONCLUSIONS: PEP shows distinct differences to CPAP with respect to its impact on ventilation distribution in healthy adults and CF subjects EIT might be used to individualise respiratory physiotherapy.

Comprehensive and accurate tracking of carbon origin of LC-tandem mass spectrometry collisional fragments for 13C-MFA.

Science.gov (United States)

Kappelmann, Jannick; Klein, Bianca; Geilenkirchen, Petra; Noack, Stephan

2017-03-01

In recent years the benefit of measuring positionally resolved 13 C-labeling enrichment from tandem mass spectrometry (MS/MS) collisional fragments for improved precision of 13 C-Metabolic Flux Analysis ( 13 C-MFA) has become evident. However, the usage of positional labeling information for 13 C-MFA faces two challenges: (1) The mass spectrometric acquisition of a large number of potentially interfering mass transitions may hamper accuracy and sensitivity. (2) The positional identity of carbon atoms of product ions needs to be known. The present contribution addresses the latter challenge by deducing the maximal positional labeling information contained in LC-ESI-MS/MS spectra of product anions of central metabolism as well as product cations of amino acids. For this purpose, we draw on accurate mass spectrometry, selectively labeled standards, and published fragmentation pathways to structurally annotate all dominant mass peaks of a large collection of metabolites, some of which with a complete fragmentation pathway. Compiling all available information, we arrive at the most detailed map of carbon atom fate of LC-ESI-MS/MS collisional fragments yet, comprising 170 intense and structurally annotated product ions with unique carbon origin from 76 precursor ions of 72 metabolites. Our 13 C-data proof that heuristic fragmentation rules often fail to yield correct fragment structures and we expose common pitfalls in the structural annotation of product ions. We show that the positionally resolved 13 C-label information contained in the product ions that we structurally annotated allows to infer the entire isotopomer distribution of several central metabolism intermediates, which is experimentally demonstrated for malate using quadrupole-time-of-flight MS technology. Finally, the inclusion of the label information from a subset of these fragments improves flux precision in a Corynebacterium glutamicum model of the central carbon metabolism.

Position-dependent Effects of Polylysine on Sec Protein Transport*

Science.gov (United States)

Liang, Fu-Cheng; Bageshwar, Umesh K.; Musser, Siegfried M.

2012-01-01

The bacterial Sec protein translocation system catalyzes the transport of unfolded precursor proteins across the cytoplasmic membrane. Using a recently developed real time fluorescence-based transport assay, the effects of the number and distribution of positive charges on the transport time and transport efficiency of proOmpA were examined. As expected, an increase in the number of lysine residues generally increased transport time and decreased transport efficiency. However, the observed effects were highly dependent on the polylysine position in the mature domain. In addition, a string of consecutive positive charges generally had a more significant effect on transport time and efficiency than separating the charges into two or more charged segments. Thirty positive charges distributed throughout the mature domain resulted in effects similar to 10 consecutive charges near the N terminus of the mature domain. These data support a model in which the local effects of positive charge on the translocation kinetics dominate over total thermodynamic constraints. The rapid translocation kinetics of some highly charged proOmpA mutants suggest that the charge is partially shielded from the electric field gradient during transport, possibly by the co-migration of counter ions. The transport times of precursors with multiple positively charged sequences, or “pause sites,” were fairly well predicted by a local effect model. However, the kinetic profile predicted by this local effect model was not observed. Instead, the transport kinetics observed for precursors with multiple polylysine segments support a model in which translocation through the SecYEG pore is not the rate-limiting step of transport. PMID:22367204

Position-dependent effects of polylysine on Sec protein transport.

Science.gov (United States)

Liang, Fu-Cheng; Bageshwar, Umesh K; Musser, Siegfried M

2012-04-13

The bacterial Sec protein translocation system catalyzes the transport of unfolded precursor proteins across the cytoplasmic membrane. Using a recently developed real time fluorescence-based transport assay, the effects of the number and distribution of positive charges on the transport time and transport efficiency of proOmpA were examined. As expected, an increase in the number of lysine residues generally increased transport time and decreased transport efficiency. However, the observed effects were highly dependent on the polylysine position in the mature domain. In addition, a string of consecutive positive charges generally had a more significant effect on transport time and efficiency than separating the charges into two or more charged segments. Thirty positive charges distributed throughout the mature domain resulted in effects similar to 10 consecutive charges near the N terminus of the mature domain. These data support a model in which the local effects of positive charge on the translocation kinetics dominate over total thermodynamic constraints. The rapid translocation kinetics of some highly charged proOmpA mutants suggest that the charge is partially shielded from the electric field gradient during transport, possibly by the co-migration of counter ions. The transport times of precursors with multiple positively charged sequences, or "pause sites," were fairly well predicted by a local effect model. However, the kinetic profile predicted by this local effect model was not observed. Instead, the transport kinetics observed for precursors with multiple polylysine segments support a model in which translocation through the SecYEG pore is not the rate-limiting step of transport.

Channel Measurements and Characteristics for Cooperative Positioning Applications

DEFF Research Database (Denmark)

Wang, Wei; Steinböck, Gerhard; Jost, Thomas

2012-01-01

We have conducted an indoor channel measurement campaign to characterize the propagation channel for the development of cooperative positioning algorithms. The campaign focused particularly on the characteristics of multi-link channels with applications to positioning. In this contribution we...... present the measurement campaign and preliminary results on correlation characteristics of the received power. It is observed that the link-pair log power is uncorrelated. Moreover, the received log power can be modeled by realizations of independent Gaussian distributions for each link, based...... on the measured results....

Probability distribution functions for intermittent scrape-off layer plasma fluctuations

Science.gov (United States)

Theodorsen, A.; Garcia, O. E.

2018-03-01

A stochastic model for intermittent fluctuations in the scrape-off layer of magnetically confined plasmas has been constructed based on a super-position of uncorrelated pulses arriving according to a Poisson process. In the most common applications of the model, the pulse amplitudes are assumed exponentially distributed, supported by conditional averaging of large-amplitude fluctuations in experimental measurement data. This basic assumption has two potential limitations. First, statistical analysis of measurement data using conditional averaging only reveals the tail of the amplitude distribution to be exponentially distributed. Second, exponentially distributed amplitudes leads to a positive definite signal which cannot capture fluctuations in for example electric potential and radial velocity. Assuming pulse amplitudes which are not positive definite often make finding a closed form for the probability density function (PDF) difficult, even if the characteristic function remains relatively simple. Thus estimating model parameters requires an approach based on the characteristic function, not the PDF. In this contribution, the effect of changing the amplitude distribution on the moments, PDF and characteristic function of the process is investigated and a parameter estimation method using the empirical characteristic function is presented and tested on synthetically generated data. This proves valuable for describing intermittent fluctuations of all plasma parameters in the boundary region of magnetized plasmas.

Distribution of Exhaled Contaminants and Personal Exposure in a Room using Three Different Air Distribution Strategies

DEFF Research Database (Denmark)

Olmedo, Inés; Nielsen, Peter V.; Adana, M. Ruiz de

2012-01-01

The level of exposure to human exhaled contaminants in a room depends not only on the air distribution system but also on people’s different positions, the distance between them, people’s activity level and height, direction of exhalation, and the surrounding temperature and temperature gradient...... between the manikins are changed to study the influence on the level of exposure. The results show that the air exhaled by a manikin flows a longer distance with a higher concentration in case of displacement ventilation than in the other two cases, indicating a significant exposure to the contaminants....... Human exhalation is studied in detail for different distribution systems: displacement and mixing ventilation as well as a system without mechanical ventilation. Two thermal manikins breathing through the mouth are used to simulate the exposure to human exhaled contaminants. The position and distance...

Effect of intrauterine position on the radiosensitivity of rat embryos

International Nuclear Information System (INIS)

Ward, W.F.; Aceto, H. Jr.; Karp, C.H.

1977-01-01

Rats were exposed to gamma rays or helium ions on one of days 4 to 9 of gestation. Embryonic survival was recorded as a function of intrauterine position at autopsy on day 20 of gestation. Embryos located at the ovarian and cervical ends of the uterus experienced higher rates of mortality than did their littermates located at the middle of the uterine horn. This effect was observed in litters exposed to both radiation modalities on all days studied. The influence of intrauterine position on embryonic survival was directly proportional to radiation dose and to the number of fetuses occupying the uterus horn. Under the least advantageous conditions (i.e., a crowded uterine horn exposed to a moderately high radiation dose), the cervical embryo's probability of survival was less than half that of the litter as a whole. A disproportionately high rate of embryonic mortality at the cervical position was also observed in litters irradiated under hypoxic conditions, suggesting that the non-random distribution of radiation effect was not the result of variations in oxygen concentration within the uterus. In contrast, there was no indication that intrauterine position influenced the distribution of gross morphologic abnormalities in irradiated litters

Investigating The Neutron Flux Distribution Of The Miniature Neutron Source Reactor MNSR Type

International Nuclear Information System (INIS)

Nguyen Hoang Hai; Do Quang Binh

2011-01-01

Neutron flux distribution is the important characteristic of nuclear reactor. In this article, four energy group neutron flux distributions of the miniature neutron source reactor MNSR type versus radial and axial directions are investigated in case the control rod is fully withdrawn. In addition, the effect of control rod positions on the thermal neutron flux distribution is also studied. The group constants for all reactor components are generated by the WIMSD code, and the neutron flux distributions are calculated by the CITATION code. The results show that the control rod positions only affect in the planning area for distribution in the region around the control rod. (author)

Maximum likelihood positioning for gamma-ray imaging detectors with depth of interaction measurement

International Nuclear Information System (INIS)

Lerche, Ch.W.; Ros, A.; Monzo, J.M.; Aliaga, R.J.; Ferrando, N.; Martinez, J.D.; Herrero, V.; Esteve, R.; Gadea, R.; Colom, R.J.; Toledo, J.; Mateo, F.; Sebastia, A.; Sanchez, F.; Benlloch, J.M.

2009-01-01

The center of gravity algorithm leads to strong artifacts for gamma-ray imaging detectors that are based on monolithic scintillation crystals and position sensitive photo-detectors. This is a consequence of using the centroids as position estimates. The fact that charge division circuits can also be used to compute the standard deviation of the scintillation light distribution opens a way out of this drawback. We studied the feasibility of maximum likelihood estimation for computing the true gamma-ray photo-conversion position from the centroids and the standard deviation of the light distribution. The method was evaluated on a test detector that consists of the position sensitive photomultiplier tube H8500 and a monolithic LSO crystal (42mmx42mmx10mm). Spatial resolution was measured for the centroids and the maximum likelihood estimates. The results suggest that the maximum likelihood positioning is feasible and partially removes the strong artifacts of the center of gravity algorithm.

Maximum likelihood positioning for gamma-ray imaging detectors with depth of interaction measurement

Energy Technology Data Exchange (ETDEWEB)

Lerche, Ch.W. [Grupo de Sistemas Digitales, ITACA, Universidad Politecnica de Valencia, 46022 Valencia (Spain)], E-mail: lerche@ific.uv.es; Ros, A. [Grupo de Fisica Medica Nuclear, IFIC, Universidad de Valencia-Consejo Superior de Investigaciones Cientificas, 46980 Paterna (Spain); Monzo, J.M.; Aliaga, R.J.; Ferrando, N.; Martinez, J.D.; Herrero, V.; Esteve, R.; Gadea, R.; Colom, R.J.; Toledo, J.; Mateo, F.; Sebastia, A. [Grupo de Sistemas Digitales, ITACA, Universidad Politecnica de Valencia, 46022 Valencia (Spain); Sanchez, F.; Benlloch, J.M. [Grupo de Fisica Medica Nuclear, IFIC, Universidad de Valencia-Consejo Superior de Investigaciones Cientificas, 46980 Paterna (Spain)

2009-06-01

The center of gravity algorithm leads to strong artifacts for gamma-ray imaging detectors that are based on monolithic scintillation crystals and position sensitive photo-detectors. This is a consequence of using the centroids as position estimates. The fact that charge division circuits can also be used to compute the standard deviation of the scintillation light distribution opens a way out of this drawback. We studied the feasibility of maximum likelihood estimation for computing the true gamma-ray photo-conversion position from the centroids and the standard deviation of the light distribution. The method was evaluated on a test detector that consists of the position sensitive photomultiplier tube H8500 and a monolithic LSO crystal (42mmx42mmx10mm). Spatial resolution was measured for the centroids and the maximum likelihood estimates. The results suggest that the maximum likelihood positioning is feasible and partially removes the strong artifacts of the center of gravity algorithm.

Regulatory Improvements for Effective Integration of Distributed Generation into Electricity Distribution Networks

International Nuclear Information System (INIS)

Scheepers, M.J.J.; Jansen, J.C.; De Joode, J.; Bauknecht, D.; Gomez, T.; Pudjianto, D.; Strbac, G.; Ropenus, S.

2007-11-01

The growth of distributed electricity supply of renewable energy sources (RES-E) and combined heat and power (CHP) - so called distributed generation (DG) - can cause technical problems for electricity distribution networks. These integration problems can be overcome by reinforcing the network. Many European Member States apply network regulation that does not account for the impact of DG growth on the network costs. Passing on network integration costs to the DG-operator who is responsible for these extra costs may result in discrimination between different DG plants and between DG and large power generation. Therefore, in many regulatory systems distribution system operators (DSOs) are not being compensated for the DG integration costs. The DG-GRID project analysed technical and economical barriers for integration of distributed generation into electricity distribution networks. The project looked into the impact of a high DG deployment on the electricity distribution system costs and the impact on the financial position of the DSO. Several ways for improving network regulation in order to compensate DSOs for the increasing DG penetration were identified and tested. The DG-GRID project looked also into stimulating network innovations through economic regulation. The project was co-financed by the European Commission and carried out by nine European universities and research institutes. This report summarises the project results and is based on a number of DG-GRID reports that describe the conducted analyses and their results

Strategic Positioning of IT in Global Organizations

DEFF Research Database (Denmark)

Siurdyban, Artur

2010-01-01

understanding of the role of IT in value creation from a business process perspective, and at the same time practitioners may use it to diagnose, communicate and plan IT positioning in their companies. The tool consists of visual maps assigning different steps of the business process management lifecycle......Executives in large global corporations are faced with a number of non-alternative decision parameters determining the strategic positioning of their IT units. These parameters include organizational structures, competence development and distribution among central and local levels, goal setting...... and type of value contributed to the organization. Although the existing body of research addresses these issues in numerous ways, the concepts have not been fully applied in practice. This paper proposes a tool for strategic positioning of IT in large global companies. It contributes to the overall...

Root and soil carbon distribution at shoulderslope and footslope positions of temperate toposequences cropped to winter wheat

DEFF Research Database (Denmark)

Chirinda, Ngoni; Roncossek, Svenja Doreen; Heckrath, Goswin Johann

2014-01-01

Crop root residues are an important source of soil organic carbon (SOC) in arable systems. However, the spatial distribution of root biomass in arable systems remains largely unknown. In this study, we determined the spatial distribution of macro-root and shoot biomass of winter wheat at shoulder...

The Beta-Lindley Distribution: Properties and Applications

Directory of Open Access Journals (Sweden)

Faton Merovci

2014-01-01

Full Text Available We introduce the new continuous distribution, the so-called beta-Lindley distribution that extends the Lindley distribution. We provide a comprehensive mathematical treatment of this distribution. We derive the moment generating function and the rth moment thus, generalizing some results in the literature. Expressions for the density, moment generating function, and rth moment of the order statistics also are obtained. Further, we also discuss estimation of the unknown model parameters in both classical and Bayesian setup. The usefulness of the new model is illustrated by means of two real data sets. We hope that the new distribution proposed here will serve as an alternative model to other models available in the literature for modelling positive real data in many areas.

INDOOR POSITIONING AND NAVIGATION BASED ON CONTROL SPHERECAL PANORAMIC IMAGES

Directory of Open Access Journals (Sweden)

T.-C. Huang

2016-06-01

Full Text Available Continuous indoor and outdoor positioning and navigation is the goal to achieve in the field of mobile mapping technology. However, accuracy of positioning and navigation will be largely degraded in indoor or occluded areas, due to receiving weak or less GNSS signals. Targeting the need of high accuracy indoor and outdoor positioning and navigation for mobile mapping applications, the objective of this study is to develop a novel method of indoor positioning and navigation with the use of spherical panoramic image (SPI. Two steps are planned in the technology roadmap. First, establishing a control SPI database that contains a good number of well-distributed control SPIs pre-acquired in the target space. A control SPI means an SPI with known exterior orientation parameters, which can be solved with a network bundle adjustment of SPIs. Having a control SPI database, the target space will be ready to provide the service of positioning and navigation. Secondly, the position and orientation of a newly taken SPI can be solved by using overlapped SPIs searched from the control SPI database. The method of matching SPIs and finding conjugate image features will be developed and tested. Two experiments will be planned and conducted in this paper to test the feasibility and validate the test results of the proposed methods. Analysis of appropriate number and distribution of needed control SPIs will also be included in the experiments with respect to different test cases.

Environmental radiation monitoring system with GPS (global positioning system)

International Nuclear Information System (INIS)

Komoto, Itsuro

2000-01-01

This system combines a radiation monitoring car with GPS and a data processor (personal computer). It distributes the position information acquired through GPS to the data such as measured environmental radiation dose rate and energy spectrum. It also displays and edits the data for each measuring position on a map. Transmitting the data to the power station through mobile phone enables plan managers to easily monitor the environmental radiation dose rate nearby and proper emergency monitoring. (author)

Distribution of age at menopause in two Danish samples

DEFF Research Database (Denmark)

Boldsen, J L; Jeune, B

1990-01-01

We analyzed the distribution of reported age at natural menopause in two random samples of Danish women (n = 176 and n = 150) to determine the shape of the distribution and to disclose any possible trends in the distribution parameters. It was necessary to correct the frequencies of the reported...... ages for the effect of differing ages at reporting. The corrected distribution of age at menopause differs from the normal distribution in the same way in both samples. Both distributions could be described by a mixture of two normal distributions. It appears that most of the parameters of the normal...... distribution mixtures remain unchanged over a 50-year time lag. The position of the distribution, that is, the mean age at menopause, however, increases slightly but significantly....

Distributional chaos for triangular maps

International Nuclear Information System (INIS)

Smital, Jaroslav; Stefankova, Marta

2004-01-01

In this paper we exhibit a triangular map F of the square with the following properties: (i) F is of type 2 ∞ but has positive topological entropy; we recall that similar example was given by Kolyada in 1992, but our argument is much simpler. (ii) F is distributionally chaotic in the wider sense, but not distributionally chaotic in the sense introduced by Schweizer and Smital [Trans. Amer. Math. Soc. 344 (1994) 737]. In other words, there are lower and upper distribution functions PHI xy and PHI xy * generated by F such that PHI xy * ≡1 and PHI xy (0 + ) uv , and PHI uv * such that PHI uv * ≡1 and PHI uv (t)=0 whenever 0 0. We also show that the two notions of distributional chaos used in the paper, for continuous maps of a compact metric space, are invariants of topological conjugacy

Coherent distributions for the rigid rotator

Energy Technology Data Exchange (ETDEWEB)

Grigorescu, Marius [CP 15-645, Bucharest 014700 (Romania)

2016-06-15

Coherent solutions of the classical Liouville equation for the rigid rotator are presented as positive phase-space distributions localized on the Lagrangian submanifolds of Hamilton-Jacobi theory. These solutions become Wigner-type quasiprobability distributions by a formal discretization of the left-invariant vector fields from their Fourier transform in angular momentum. The results are consistent with the usual quantization of the anisotropic rotator, but the expected value of the Hamiltonian contains a finite “zero point” energy term. It is shown that during the time when a quasiprobability distribution evolves according to the Liouville equation, the related quantum wave function should satisfy the time-dependent Schrödinger equation.

Fusion barrier distributions and fission anisotropies

International Nuclear Information System (INIS)

Hinde, D.J.; Morton, C.R.; Dasgupta, M.; Leigh, J.R.; Lestone, J.P.; Lemmon, R.C.; Mein, J.C.; Newton, J.O.; Timmers, H.; Rowley, N.; Kruppa, A.T.

1995-01-01

Fusion excitation functions for 16,17 O+ 144 Sm have been measured to high precision. The extracted fusion barrier distributions show a double-peaked structure interpreted in terms of coupling to inelastic collective excitations of the target. The effect of the positive Q-value neutron stripping channel is evident in the reaction with 17 O. Fission and evaporation residue cross-sections and excitation functions have been measured for the reaction of 16 O+ 208 Pb and the fusion barrier distribution and fission anisotropies determined. It is found that the moments of the fusion l-distribution determined from the fusion and fission measurements are in good agreement. ((orig.))

Influence of Distributed Residential Energy Storage on Voltage in Rural Distribution Network and Capacity Configuration

Science.gov (United States)

Liu, Lu; Tong, Yibin; Zhao, Zhigang; Zhang, Xuefen

2018-03-01

Large-scale access of distributed residential photovoltaic (PV) in rural areas has solved the voltage problem to a certain extent. However, due to the intermittency of PV and the particularity of rural residents’ power load, the problem of low voltage in the evening peak remains to be resolved. This paper proposes to solve the problem by accessing residential energy storage. Firstly, the influence of access location and capacity of energy storage on voltage distribution in rural distribution network is analyzed. Secondly, the relation between the storage capacity and load capacity is deduced for four typical load and energy storage cases when the voltage deviation meets the demand. Finally, the optimal storage position and capacity are obtained by using PSO and power flow simulation.

Entropies of negative incomes, Pareto-distributed loss, and financial crises.

Science.gov (United States)

Gao, Jianbo; Hu, Jing; Mao, Xiang; Zhou, Mi; Gurbaxani, Brian; Lin, Johnny

2011-01-01

Health monitoring of world economy is an important issue, especially in a time of profound economic difficulty world-wide. The most important aspect of health monitoring is to accurately predict economic downturns. To gain insights into how economic crises develop, we present two metrics, positive and negative income entropy and distribution analysis, to analyze the collective "spatial" and temporal dynamics of companies in nine sectors of the world economy over a 19 year period from 1990-2008. These metrics provide accurate predictive skill with a very low false-positive rate in predicting downturns. The new metrics also provide evidence of phase transition-like behavior prior to the onset of recessions. Such a transition occurs when negative pretax incomes prior to or during economic recessions transition from a thin-tailed exponential distribution to the higher entropy Pareto distribution, and develop even heavier tails than those of the positive pretax incomes. These features propagate from the crisis initiating sector of the economy to other sectors.

Entropies of negative incomes, Pareto-distributed loss, and financial crises.

Directory of Open Access Journals (Sweden)

Jianbo Gao

Full Text Available Health monitoring of world economy is an important issue, especially in a time of profound economic difficulty world-wide. The most important aspect of health monitoring is to accurately predict economic downturns. To gain insights into how economic crises develop, we present two metrics, positive and negative income entropy and distribution analysis, to analyze the collective "spatial" and temporal dynamics of companies in nine sectors of the world economy over a 19 year period from 1990-2008. These metrics provide accurate predictive skill with a very low false-positive rate in predicting downturns. The new metrics also provide evidence of phase transition-like behavior prior to the onset of recessions. Such a transition occurs when negative pretax incomes prior to or during economic recessions transition from a thin-tailed exponential distribution to the higher entropy Pareto distribution, and develop even heavier tails than those of the positive pretax incomes. These features propagate from the crisis initiating sector of the economy to other sectors.

Position calibration of silicon strip detector using quasi-elastic scattering of 16O+197Au

International Nuclear Information System (INIS)

Yan Wenqi; Hu Hailong; Zhang Gaolong

2013-01-01

Background: Elastic scattering is induced by weakly unstable nuclei. Generally, a good angular resolution for angular distribution of elastic scattering is needed. The silicon strip detector is often used for this kind of experiment. Purpose: In order to use silicon strip detector to study the elastic scattering of weakly unbound nuclei, it is important to get the information of its position calibration. It is well known that the elastic scattering of stable nuclei has a good angular distribution and many experimental data have been obtained. Methods: So the scattering of stable nuclei can be used to calibrate the position information of silicon strip detector. In this experiment, the positions of silicon strip detectors are calibrated using 101 MeV and 59 MeV 16 O scattering on the 197 Au target. Results: The quasi-elastic peaks can be observed in the silicon strip detectors and the counts of quasi-elastic 16 O can be obtained. The solid angles of the silicon strip detectors are calibrated by using alpha source which has three alpha energy values. The angular distribution of quasi-elastic scattering of 16 O+ 197 Au is obtained at these two energy values. Conclusions: The experimental data of angular distribution are reasonable and fit for the principle of angular distribution of elastic scattering. It is concluded that in the experiment these silicon strip detectors can accurately give the position information and can be used for the elastic scattering experiment. (authors)

Precise Positioning Method for Logistics Tracking Systems Using Personal Handy-Phone System Based on Mahalanobis Distance

Science.gov (United States)

Yokoi, Naoaki; Kawahara, Yasuhiro; Hosaka, Hiroshi; Sakata, Kenji

Focusing on the Personal Handy-phone System (PHS) positioning service used in physical distribution logistics, a positioning error offset method for improving positioning accuracy is invented. A disadvantage of PHS positioning is that measurement errors caused by the fluctuation of radio waves due to buildings around the terminal are large, ranging from several tens to several hundreds of meters. In this study, an error offset method is developed, which learns patterns of positioning results (latitude and longitude) containing errors and the highest signal strength at major logistic points in advance, and matches them with new data measured in actual distribution processes according to the Mahalanobis distance. Then the matching resolution is improved to 1/40 that of the conventional error offset method.

A new kind of droplet space distribution measuring method

International Nuclear Information System (INIS)

Ma Chao; Bo Hanliang

2012-01-01

A new kind of droplet space distribution measuring technique was introduced mainly, and the experimental device which was designed for the measuring the space distribution and traces of the flying film droplet produced by the bubble breaking up near the free surface of the water. This experiment was designed with a kind of water-sensitivity test paper (rice paper) which could record the position and size of the colored scattering droplets precisely. The rice papers were rolled into cylinders with different diameters by using tools. The bubbles broke up exactly in the center of the cylinder, and the space distribution and the traces of the droplets would be received by analysing all the positions of the droplets produced by the same size bubble on the rice papers. (authors)

Global Positioning System – A new tool to measure the distribution of anaemia and nutritional status of children (5-10years in a rural area, South India

Directory of Open Access Journals (Sweden)

Sathish Chandra MR

2014-11-01

Full Text Available Introduction: The Global Positioning System (GPS is a satellite based navigation system which is of late being used in the health field. Objectives: 1.To describe the geographical distribution of anaemia and malnutrition with GPS; 2.To assess the prevalence of anaemia and malnutrition in children aged 5-10 years. Subjects and methods: This exploratory study was conducted over a period of 2 months in the rural field practice area of a medical college situated in Bangalore during the months of June - July, 2012. Children in the age group of 5-10 years of age were the study subjects. Results: GPS was used for the describing the geographical distribution of anaemia and nutrition status on the Google earth map. The prevalence of anaemia in the study subjects was 8.7%.The prevalence of underweight, stunting, thinness and severe thinness among the study subjects was 52.8%, 28.5%, 23.5 % and 29.1% respectively, however  overweight  and obesity was observed only in 0.9 % and 1.2% of the study subjects respectively. Conclusion: GPS was easy to use and was able to demonstrate the actual distribution of morbidity at the household level in the rural area.

Positioning bedridden patients to reduce interface pressures over the sacrum and great trochanter.

Science.gov (United States)

Yoshikawa, Y; Maeshige, N; Sugimoto, M; Uemura, M; Noguchi, M; Terashi, H

2015-07-01

In this study, we evaluated the effect of hip-joint rotation on the interface pressure over the sacrum and greater trochanter with a new protocol for positioning of bedridden elderly patients. The interface pressure values over the sacrum and greater trochanter in bedridden patients were evaluated. These were collected in the supine position, 90° lateral position, and 30° and 40° laterally inclined positions with external rotation or neutral positioning of the hip joint. Each interface pressure was assessed with a device measuring pressure distribution, after which, the peak pressure index (PPI) was calculated. In the 17 patients examined, the PPI over the sacrum in the supine position was significantly greater than that in other positions. In the 30° and 40° laterally inclined positions, the PPIs over the greater trochanter were significantly lower in the neutral position of the hip joint compared with those in the external rotation position. Our findings revealed the effects of hip-joint rotation on the interface pressure for the greater trochanter, possibly due to the increased distance between the greater trochanter and the sacrum caused by neutral position of the hip joint. The results demonstrate that it is to best place the hip joint in a neutral position when the legs are in contact with the bed in order to distribute the pressure over the greater trochanter in the 30° and 40° laterally inclined positions. These results can be applied to the clinical setting to improve patient positioning and decrease pressure ulcers. The authors declare that they have no competing financial interests.

Temperature distributions in 136 superficial radiothermotherapies

International Nuclear Information System (INIS)

Willich, N.; Duve, S.; Pfluger, T.; Bachmeier, K.

1992-01-01

Temperature distributions from 136 superficial radiothermotherapies in patients were analysed and three-dimensionally reconstructed. The calculation of mean values and standard deviations of the temperature measuring probes considering water bolus temperature, master probe temperature, site of the probes relatively to different applicator positions and site of the probes in the heated tissues yielded satisfactory temperature distributions for chest wall treatment in contrast to other regions of the body. Radiothermotherapy was statistically not superior to radiotherapy alone with respect to local tumor control. (authors)

Generalised extreme value distributions provide a natural hypothesis for the shape of seed mass distributions.

Directory of Open Access Journals (Sweden)

Will Edwards

Full Text Available Among co-occurring species, values for functionally important plant traits span orders of magnitude, are uni-modal, and generally positively skewed. Such data are usually log-transformed "for normality" but no convincing mechanistic explanation for a log-normal expectation exists. Here we propose a hypothesis for the distribution of seed masses based on generalised extreme value distributions (GEVs, a class of probability distributions used in climatology to characterise the impact of event magnitudes and frequencies; events that impose strong directional selection on biological traits. In tests involving datasets from 34 locations across the globe, GEVs described log10 seed mass distributions as well or better than conventional normalising statistics in 79% of cases, and revealed a systematic tendency for an overabundance of small seed sizes associated with low latitudes. GEVs characterise disturbance events experienced in a location to which individual species' life histories could respond, providing a natural, biological explanation for trait expression that is lacking from all previous hypotheses attempting to describe trait distributions in multispecies assemblages. We suggest that GEVs could provide a mechanistic explanation for plant trait distributions and potentially link biology and climatology under a single paradigm.

Determination of User Distribution Image Size and Position of Each Observation Area of Meteorological Imager in COMS

Directory of Open Access Journals (Sweden)

Jeong-Soo Seo

2006-12-01

Full Text Available In this paper, requirements of Meteorological Administration about Meteorological Imager (MI of Communications, Ocean and Meteorological Satellite (COMS is analyzed for the design of COMS ground station and according to the analysis results, the distribution image size of each observation area suitable for satellite Field Of View (FOV stated at the requirements of meteorological administration is determined and the precise satellite FOV and the size of distribution image is calculated on the basis of the image size of the determined observation area. The results in this paper were applied to the detailed design for COMS ground station and also are expected to be used for the future observation scheduling and the scheduling of distribution of user data.

Nomogram for predicting the probability of the positive outcome of ...

African Journals Online (AJOL)

F.A. Yeboah

distribution, the median and inter quartile (IQR) values were used. ... Crude or adjusted odds ratios and ... model, the estimated probability of a positive biopsy was calcu- ..... Gratitude goes to workers at Department of Surgery (Urology Unit).

OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis

Directory of Open Access Journals (Sweden)

Nielsen Lars K

2009-05-01

Full Text Available Abstract Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i tracer cultivation on 13C substrates, (ii 13C labelling analysis by mass spectrometry and (iii mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly ( Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and

Automatic approach to deriving fuzzy slope positions

Science.gov (United States)

Zhu, Liang-Jun; Zhu, A.-Xing; Qin, Cheng-Zhi; Liu, Jun-Zhi

2018-03-01

Fuzzy characterization of slope positions is important for geographic modeling. Most of the existing fuzzy classification-based methods for fuzzy characterization require extensive user intervention in data preparation and parameter setting, which is tedious and time-consuming. This paper presents an automatic approach to overcoming these limitations in the prototype-based inference method for deriving fuzzy membership value (or similarity) to slope positions. The key contribution is a procedure for finding the typical locations and setting the fuzzy inference parameters for each slope position type. Instead of being determined totally by users in the prototype-based inference method, in the proposed approach the typical locations and fuzzy inference parameters for each slope position type are automatically determined by a rule set based on prior domain knowledge and the frequency distributions of topographic attributes. Furthermore, the preparation of topographic attributes (e.g., slope gradient, curvature, and relative position index) is automated, so the proposed automatic approach has only one necessary input, i.e., the gridded digital elevation model of the study area. All compute-intensive algorithms in the proposed approach were speeded up by parallel computing. Two study cases were provided to demonstrate that this approach can properly, conveniently and quickly derive the fuzzy slope positions.

Multi-platform Integrated Positioning and Attitude Determination using GNSS

NARCIS (Netherlands)

Buist, P.J.

2013-01-01

There is trend in spacecraft engineering toward distributed systems where a number of smaller spacecraft work as a larger satellite. However, in order to make the small satellites work together as a single large platform, the precise relative positions (baseline) and orientations (attitude) of the

Beam position monitor data acquisition for the Advanced Photon Source

International Nuclear Information System (INIS)

Lenkszus, F.R.; Kahana, E.; Votaw, A.J.; Decker, G.A.; Chung, Y.; Ciarlette, D.J.; Laird, R.J.

1993-01-01

This paper describes the Beam Position Monitor (BPM) data acquisition scheme for the Advanced Photon Source (APS) storage ring. The storage ring contains 360 beam position monitors distributed around its 1104-meter circumference. The beam position monitor data acquisition system is capable of making turn-by-turn measurements of all BPMs simultaneously. It is VXI-based with each VXI crate containing the electronics for 9 BPMS. The VXI Local Bus is used to provide sustained data transfer rates of up to 13 mega-transfers per second to a scanner module. The system provides single-bunch tracking, bunch-to-bunch measurements, fast digital-averaged positions, beam position history buffering, and synchronized multi-turn measurements. Data is accessible to the control system VME crates via an MXI bus. Dedicated high-speed ports are provided to supply position data to beam orbit feedback systems

Unequally distributed psychological assets: are there social disparities in optimism, life satisfaction, and positive affect?

Science.gov (United States)

Boehm, Julia K; Chen, Ying; Williams, David R; Ryff, Carol; Kubzansky, Laura D

2015-01-01

Socioeconomic status is associated with health disparities, but underlying psychosocial mechanisms have not been fully identified. Dispositional optimism may be a psychosocial process linking socioeconomic status with health. We hypothesized that lower optimism would be associated with greater social disadvantage and poorer social mobility. We also investigated whether life satisfaction and positive affect showed similar patterns. Participants from the Midlife in the United States study self-reported their optimism, satisfaction, positive affect, and socioeconomic status (gender, race/ethnicity, education, occupational class and prestige, income). Social disparities in optimism were evident. Optimistic individuals tended to be white and highly educated, had an educated parent, belonged to higher occupational classes with more prestige, and had higher incomes. Findings were generally similar for satisfaction, but not positive affect. Greater optimism and satisfaction were also associated with educational achievement across generations. Optimism and life satisfaction are consistently linked with socioeconomic advantage and may be one conduit by which social disparities influence health.

Positioning accuracy of the neurotron 1000

International Nuclear Information System (INIS)

Cox, Richard S.; Murphy, Martin J.

1995-01-01

Purpose: The Neurotron 1000 is a novel treatment machine under development for frameless stereotaxic radiosurgery that consists of a compact X-band accelerator mounted on a robotic arm. The therapy beam is guided to the lesion by an imaging system, which includes two diagnostic x-ray cameras that view the patient during treatment. Patient position and motion are measured by the imaging system and appropriate corrections are communicated in real time to the robotic arm for beam targeting and motion tracking. The three tests reported here measured the pointing accuracy of the therapy beam and the present capability of the imaging guidance system. Materials and Methods: 1) The positioning and pointing test measured the ability of the robotic arm to direct the beam through a test isocenter from arbitrary arm positions. The test isocenter was marked by a small light-sensitive crystal and the beam axis was simulated by a laser. The robot was directed to move the linac to a variety of positions, aiming the laser at the crystal detector from each position. The distance of the beam axis from the crystal was measured for each robot position. 2) The imaging-guidance system was tested by moving phantoms about in the field of view of the camera by precisely known displacements and comparing the guidance system's measurement of the phantom position with the its actual position. 3) The system's overall pointing and tracking capability was measured by an end-to-end test using a dosimetric phantom containing radiochromic film. The phantom was imaged by CT to locate the center of the cubical film package. A set of isocentric robotic paths was calculated to produce a spherical dose distribution at the center of the film package. The phantom with the film was then irradiated by the therapy beam as the robot executed the path, with the imaging system providing the beam targeting directions. Results: 1) The positioning and pointing test was performed for paths consisting of spirals and

Influence of patient mispositioning on SAR distribution and simulated temperature in regional deep hyperthermia

Science.gov (United States)

Aklan, Bassim; Gierse, Pia; Hartmann, Josefin; Ott, Oliver J.; Fietkau, Rainer; Bert, Christoph

2017-06-01

Patient positioning plays an important role in regional deep hyperthermia to obtain a successful hyperthermia treatment. In this study, the influence of possible patient mispositioning was systematically assessed on specific absorption rate (SAR) and temperature distribution. With a finite difference time domain approach, the SAR and temperature distributions were predicted for six patients at 312 positions. Patient displacements and rotations as well as the combination of both were considered inside the Sigma-Eye applicator. Position sensitivity is assessed for hyperthermia treatment planning -guided steering, which relies on model-based optimization of the SAR and temperature distribution. The evaluation of the patient mispositioning was done with and without optimization. The evaluation without optimization was made by creating a treatment plan for the patient reference position in the center of the applicator and applied for all other positions, while the evaluation with optimization was based on creating an individual plan for each position. The parameter T90 was used for the temperature evaluation, which was defined as the temperature that covers 90% of the gross tumor volume (GTV). Furthermore, the hotspot tumor quotient (HTQ) was used as a goal function to assess the quality of the SAR and temperature distribution. The T90 was shown considerably dependent on the position within the applicator. Without optimization, the T90 was clearly decreased below 40 °C by patient shifts and the combination of shifts and rotations. However, the application of optimization for each positon led to an increase of T90 in the GTV. Position inaccuracies of less than 1 cm in the X-and Y-directions and 2 cm in the Z-direction, resulted in an increase of HTQ of less than 5%, which does not significantly affect the SAR and temperature distribution. Current positioning precision is sufficient in the X (right-left)-direction, but position accuracy is required in the Y-and Z-directions.

Non-homogeneous Behaviour of the Spatial Distribution of Macrospicules

Science.gov (United States)

Gyenge, N.; Bennett, S.; Erdélyi, R.

2015-03-01

In this paper the longitudinal and latitudinal spatial distribution of macrospicules is examined. We found a statistical relationship between the active longitude (determined by sunspot groups) and the longitudinal distribution of macrospicules. This distribution of macrospicules shows an inhomogeneity and non-axisymmetrical behaviour in the time interval between June 2010 and December 2012, covered by observations of the Solar Dynamic Observatory (SDO) satellite. The enhanced positions of the activity and its time variation have been calculated. The migration of the longitudinal distribution of macrospicules shows a similar behaviour to that of the sunspot groups.

[Analysis for Discordance of Positive and Negative Blood Typing by Gel Card].

Science.gov (United States)

Li, Cui-Ying; Xu, Hong; Lei, Hui-Fen; Liu, Juan; Li, Xiao-Wei

2017-08-01

To explore the method of Gel card identifying ABO blood group, determine the inconsistent cause and the distribution of disease affecting factors, and put forward a method of its solutions. To collect 240 positive and negative typing-discordant blood speciments from patients examined by Gel card and send these speciments to blood type reference laboratory for examining with the classic tube method and serological test, such as salivary blood-group substance, in order to performe genotyping method when serologic test can not be determined. Among 240 positive and negative typing-discordant blood speciments from patients examined by Gel card, 107 blood speciments were positive and negative consistent examined by false agglutination test (44.58%), 133 blood specinents were discordent examined by false agglutination (55.42%), out of them, 35 cases (14.58%) with inconsistent cold agglutination test, 22 cases (9.17%) with weakened AB antigenicity, 16 cases (6.67%) with ABO subtyping, 12 cases (5.00%) with positive direct antiglobulin test, 11 cases (4.58%) with reduced or without antibodies, 11 cases (4.58%) with false aggregation caused by drugs or protein, 11 cases (4.58%) with salivary blood-type substances, 8 cases (3.33%) with non-ABO alloantibody, and 7 cases (2.92%) with allogeneic bone marrow transplantation. The distribution of disease were following: blood disease (16.83%), tumor (11.88%), and cardiopulmonary diseases (11.39%); chi-square test results indicated that the distribution significantly different. The analysis of ABO blood grouping shows a variety factors influencing positive and negative blood typing, and the Gel Card identification can produc more false positive blood types. Therefore, more attention should be paid on the high incidence diseases, such as blood disease, tumor, and cardiopulmonary disease.

Using the GB2 Income Distribution

Directory of Open Access Journals (Sweden)

Duangkamon Chotikapanich

2018-04-01

Full Text Available To use the generalized beta distribution of the second kind (GB2 for the analysis of income and other positively skewed distributions, knowledge of estimation methods and the ability to compute quantities of interest from the estimated parameters are required. We review estimation methodology that has appeared in the literature, and summarize expressions for inequality, poverty, and pro-poor growth that can be used to compute these measures from GB2 parameter estimates. An application to data from China and Indonesia is provided.

High Voltage Distribution System (HVDS) as a better system compared to Low Voltage Distribution System (LVDS) applied at Medan city power network

Science.gov (United States)

Dinzi, R.; Hamonangan, TS; Fahmi, F.

2018-02-01

In the current distribution system, a large-capacity distribution transformer supplies loads to remote locations. The use of 220/380 V network is nowadays less common compared to 20 kV network. This results in losses due to the non-optimal distribution transformer, which neglected the load location, poor consumer profile, and large power losses along the carrier. This paper discusses how high voltage distribution systems (HVDS) can be a better system used in distribution networks than the currently used distribution system (Low Voltage Distribution System, LVDS). The proposed change of the system into the new configuration is done by replacing a large-capacity distribution transformer with some smaller-capacity distribution transformers and installed them in positions that closest to the load. The use of high voltage distribution systems will result in better voltage profiles and fewer power losses. From the non-technical side, the annual savings and payback periods on high voltage distribution systems will also be the advantage.

Wigner Ville Distribution in Signal Processing, using Scilab Environment

Directory of Open Access Journals (Sweden)

Petru Chioncel

2011-01-01

Full Text Available The Wigner Ville distribution offers a visual display of quantitative information about the way a signal’s energy is distributed in both, time and frequency. Through that, this distribution embodies the fundamentally concepts of the Fourier and time-domain analysis. The energy of the signal is distributed so that specific frequencies are localized in time by the group delay time and at specifics instants in time the frequency is given by the instantaneous frequency. The net positive volum of the Wigner distribution is numerically equal to the signal’s total energy. The paper shows the application of the Wigner Ville distribution, in the field of signal processing, using Scilab environment.

Mansion, A Distributed Multi-Agent System

NARCIS (Netherlands)

van t Noordende, G.; Brazier, F.M.; Tanenbaum, A.S.

2001-01-01

In this position summary we present work in progress on a worldwide, scalable multi-agent system, based on a paradigm of hyperlinked rooms. The framework offers facilities for managing distribution, security and mobility aspects for both active elements (agents) and passive elements (objects) in the

Extraction of density distributions and particle locations from hologram images

International Nuclear Information System (INIS)

Ikeda, Koh; Okamoto, Koji; Kato, Fumitake; Shimizu, Isao.

1996-01-01

In this study, the simultaneous measurement technique for three-dimensional density and three-dimensional velocity distributions was evaluated. The Holographic Particle Image Velocimetry (HPIV) was the technique to record the three-dimensional position of the tracer particle on the hologram. In the hologram, the interferogram between reference beam and particle scattering were recorded. When there were density distributions in the interrogation region, the plane optical wave may be modulated because of the difference of the refraction indices. Then, both of the plane wave modulated by density and the spherical wave by particle scatter were interfered with the reference beam, being recorded on the hologram. With reconstructing the hologram, the both of the modulated plane wave and spherical wave were reconstructed. Since the plane wave and spherical wave had low and high frequency, respectively, the plane wave was reconstructed with the low-pass filter, resulting in the information of the density distributions to be obtained. With the high-pass filter, the particle three-dimensional positions was determined, i.e., the same procedure with the original HPIV technique. In the experiment, a jet of carbon-dioxide into air with mist were measured. Both mist particle position and the fringe shift caused by the density distribution were well observed, showing the effectiveness of the proposed technique. (author)

Effect of position and momentum constraints on charge distribution in heavy-ion collisions

International Nuclear Information System (INIS)

Rajni; Kumar, Suneel

2012-01-01

The rich phenomenology of multifragmentation has been widely explored after two decades of its discovery. It has been experimentally shown that in one single heavy ion collision many intermediate mass fragments (IMFs) are produced, where IMFs are defined as fragments with 5 ≤ A ≤ A tot /6. In the earlier literature, the multifragmentation was studied by Jakobsson et al. who measured the charge particle distribution along with their kinetic energy spectra in 16 O/ 36 Ar induced reaction between 25 and 200 MeV/nucleon representing the various phenomena in heavy ion collisions

Limit distributions of random walks on stochastic matrices

Indian Academy of Sciences (India)

condition that μm(P) > 0 for some positive integer m (as opposed to just 1, instead of m, considered in [1]), where μm is the ...... Limit distributions of random walks. 611. PROPOSITION 3.2. Let f be as introduced before Proposition 3.1. The probability distribution λ is the image of π by the map b ↦→ f (b). In other words, λ = ∑.

Researches on Position Detection for Vacuum Switch Electrode

Science.gov (United States)

Dong, Huajun; Guo, Yingjie; Li, Jie; Kong, Yihan

2018-03-01

Form and transformation character of vacuum arc is important influencing factor on the vacuum switch performance, and the dynamic separations of electrode is the chief effecting factor on the transformation of vacuum arcs forms. Consequently, how to detect the position of electrode to calculate the separations in the arcs image is of great significance. However, gray level distribution of vacuum arcs image isn’t even, the gray level of burning arcs is high, but the gray level of electrode is low, meanwhile, the forms of vacuum arcs changes sharply, the problems above restrict electrode position detection precisely. In this paper, algorithm of detecting electrode position base on vacuum arcs image was proposed. The digital image processing technology was used in vacuum switch arcs image analysis, the upper edge and lower edge were detected respectively, then linear fitting was done using the result of edge detection, the fitting result was the position of electrode, thus, accurate position detection of electrode was realized. From the experimental results, we can see that: algorithm described in this paper detected upper and lower edge of arcs successfully and the position of electrode was obtained through calculation.

Dust charging processes with a Cairns-Tsallis distribution function with negative ions

Energy Technology Data Exchange (ETDEWEB)

Abid, A. A., E-mail: abidaliabid1@hotmail.com [Applied Physics Department, Federal Urdu University of Arts, Science and Technology, Islamabad Campus, Islamabad 45320 (Pakistan); Khan, M. Z., E-mail: mzk-qau@yahoo.com [Applied Physics Department, Federal Urdu University of Arts, Science and Technology, Islamabad Campus, Islamabad 45320 (Pakistan); Plasma Technology Research Center, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yap, S. L. [Plasma Technology Research Center, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia); Terças, H., E-mail: hugo.tercas@tecnico.ul.pt [Physics of Information Group, Instituto de Telecomunicações, Av. Rovisco Pais, Lisbon 1049-001 (Portugal); Mahmood, S. [Science Place, University of Saskatchewan, Saskatoon, Saskatchewan S7N5A2 (Canada)

2016-01-15

Dust grain charging processes are presented in a non-Maxwellian dusty plasma following the Cairns-Tsallis (q, α)–distribution, whose constituents are the electrons, as well as the positive/negative ions and negatively charged dust grains. For this purpose, we have solved the current balance equation for a negatively charged dust grain to achieve an equilibrium state value (viz., q{sub d} = constant) in the presence of Cairns-Tsallis (q, α)–distribution. In fact, the current balance equation becomes modified due to the Boltzmannian/streaming distributed negative ions. It is numerically found that the relevant plasma parameters, such as the spectral indexes q and α, the positive ion-to-electron temperature ratio, and the negative ion streaming speed (U{sub 0}) significantly affect the dust grain surface potential. It is also shown that in the limit q → 1 the Cairns-Tsallis reduces to the Cairns distribution; for α = 0 the Cairns-Tsallis distribution reduces to pure Tsallis distribution and the latter reduces to Maxwellian distribution for q → 1 and α = 0.

Dust charging processes with a Cairns-Tsallis distribution function with negative ions

International Nuclear Information System (INIS)

Abid, A. A.; Khan, M. Z.; Yap, S. L.; Terças, H.; Mahmood, S.

2016-01-01

Dust grain charging processes are presented in a non-Maxwellian dusty plasma following the Cairns-Tsallis (q, α)–distribution, whose constituents are the electrons, as well as the positive/negative ions and negatively charged dust grains. For this purpose, we have solved the current balance equation for a negatively charged dust grain to achieve an equilibrium state value (viz., q d  = constant) in the presence of Cairns-Tsallis (q, α)–distribution. In fact, the current balance equation becomes modified due to the Boltzmannian/streaming distributed negative ions. It is numerically found that the relevant plasma parameters, such as the spectral indexes q and α, the positive ion-to-electron temperature ratio, and the negative ion streaming speed (U 0 ) significantly affect the dust grain surface potential. It is also shown that in the limit q → 1 the Cairns-Tsallis reduces to the Cairns distribution; for α = 0 the Cairns-Tsallis distribution reduces to pure Tsallis distribution and the latter reduces to Maxwellian distribution for q → 1 and α = 0

Mathematical Model to estimate the wind power using four-parameter Burr distribution

Science.gov (United States)

Liu, Sanming; Wang, Zhijie; Pan, Zhaoxu

2018-03-01

When the real probability of wind speed in the same position needs to be described, the four-parameter Burr distribution is more suitable than other distributions. This paper introduces its important properties and characteristics. Also, the application of the four-parameter Burr distribution in wind speed prediction is discussed, and the expression of probability distribution of output power of wind turbine is deduced.

Future changes in South American biomass distributions, biome distributions and plant trait spectra is dependent on applied atmospheric forcings.

Science.gov (United States)

Langan, Liam; Scheiter, Simon; Higgins, Steven

2017-04-01

It remains poorly understood why the position of the forest-savanna biome boundary, in a domain defined by precipitation and temperature, differs in South America, Africa and Australia. Process based Dynamic Global Vegetation Models (DGVMs) are a valuable tool to investigate the determinants of vegetation distributions, however, many DGVMs fail to predict the spatial distribution or indeed presence of the South American savanna biome. Evidence suggests fire plays a significant role in mediating forest-savanna biome boundaries, however, fire alone appear to be insufficient to predict these boundaries in South America. We hypothesize that interactions between precipitation, constraints on tree rooting depth and fire, affect the probability of savanna occurrence and the position of the savanna-forest boundary. We tested our hypotheses at tropical forest and savanna sites in Brazil and Venezuela using a novel DGVM, aDGVM2, which allows plant trait spectra, constrained by trade-offs between traits, to evolve in response to abiotic and biotic conditions. Plant hydraulics is represented by the cohesion-tension theory, this allowed us to explore how soil and plant hydraulics control biome distributions and plant traits. The resulting community trait distributions are emergent properties of model dynamics. We showed that across much of South America the biome state is not determined by climate alone. Interactions between tree rooting depth, fire and precipitation affected the probability of observing a given biome state and the emergent traits of plant communities. Simulations where plant rooting depth varied in space provided the best match to satellite derived biomass estimates and generated biome distributions that reproduced contemporary biome maps well. Future projections showed that biomass distributions, biome distributions and plant trait spectra will change, however, the magnitude of these changes are highly dependent on the applied atmospheric forcings.

Investigating the effects of strategic positioning for development of modern banking services

Directory of Open Access Journals (Sweden)

Vahid Anvar Keivi

2014-05-01

Full Text Available During the past few years, there have been tremendous changes on banking services and many bank customers are able to do their daily banking activities using recent advances of technology such as internet banking, telephone banking, etc. In this paper, we present an empirical investigation on the effects of strategic positioning for development of modern banking services. The proposed study designs a questionnaire in Likert scale and distributes it among some 385 randomly selected people who live in Tehran in 2013. The questionnaire consists of seven factors including property positioning, advantage positioning, consumer positioning, user positioning, competitive advantage positioning, quality positioning and merchandise category positioning. Using Spearman correlation as well as stepwise regression technique, the study has determined positive and meaningful relationships between different components of strategy positioning development of modern banking services.

A Distribution-class Locational Marginal Price (DLMP) Index for Enhanced Distribution Systems

Science.gov (United States)

Akinbode, Oluwaseyi Wemimo

The smart grid initiative is the impetus behind changes that are expected to culminate into an enhanced distribution system with the communication and control infrastructure to support advanced distribution system applications and resources such as distributed generation, energy storage systems, and price responsive loads. This research proposes a distribution-class analog of the transmission LMP (DLMP) as an enabler of the advanced applications of the enhanced distribution system. The DLMP is envisioned as a control signal that can incentivize distribution system resources to behave optimally in a manner that benefits economic efficiency and system reliability and that can optimally couple the transmission and the distribution systems. The DLMP is calculated from a two-stage optimization problem; a transmission system OPF and a distribution system OPF. An iterative framework that ensures accurate representation of the distribution system's price sensitive resources for the transmission system problem and vice versa is developed and its convergence problem is discussed. As part of the DLMP calculation framework, a DCOPF formulation that endogenously captures the effect of real power losses is discussed. The formulation uses piecewise linear functions to approximate losses. This thesis explores, with theoretical proofs, the breakdown of the loss approximation technique when non-positive DLMPs/LMPs occur and discusses a mixed integer linear programming formulation that corrects the breakdown. The DLMP is numerically illustrated in traditional and enhanced distribution systems and its superiority to contemporary pricing mechanisms is demonstrated using price responsive loads. Results show that the impact of the inaccuracy of contemporary pricing schemes becomes significant as flexible resources increase. At high elasticity, aggregate load consumption deviated from the optimal consumption by up to about 45 percent when using a flat or time-of-use rate. Individual load

Position-momentum uncertainty relations in the presence of quantum memory

DEFF Research Database (Denmark)

Furrer, Fabian; Berta, Mario; Tomamichel, Marco

2014-01-01

A prominent formulation of the uncertainty principle identifies the fundamental quantum feature that no particle may be prepared with certain outcomes for both position and momentum measurements. Often the statistical uncertainties are thereby measured in terms of entropies providing a clear oper....... As an illustration, we evaluate the uncertainty relations for position and momentum measurements, which is operationally significant in that it implies security of a quantum key distribution scheme based on homodyne detection of squeezed Gaussian states....

Energy transfer properties and mechanisms

International Nuclear Information System (INIS)

1991-01-01

This report discusses the energy transfer mechanisms in azulene, benzene, toluene, and isotopomers. Also discussed is the coupled energy reservoirs model, quantum effects in energy transfer, NO 2 energy transfer, densities of states, the reactant states model, and O 3 excited electronic states

Job-sharing a clinical teacher's position: an evaluation.

Science.gov (United States)

Williams, S; Murphy, L

1994-01-01

The aim of this study was to evaluate the effects on staff of having two teachers share one clinical teaching position in their intensive care unit (ICU). Three, six and 12 months after the job-sharing arrangement was initiated, an 11 item questionnaire was distributed to 26 students in post-registration critical care courses, 41 clinical staff in ICU and 9 RN-managers with responsibilities for the unit. The overall response rate to the three questionnaires was 58%. All groups agreed that job-sharing was a viable alternative to full-time work. Three months after the shared position was initiated, there was uncertainty about the consistency of the teachers' performance and the adequacy of communication between them. Nine months later, there was a high level of positive responses to all areas of the teachers' performance. Most respondents felt they could approach either teacher and that more diverse ideas were generated by having two people in the teaching position.

A tomographic study of the condyle position in temporomandibular disorders

International Nuclear Information System (INIS)

Choi, Sung Youn; Ryu, Young Kyu

1988-01-01

The aim of this study was to determine whether T.M.J. tomographic examination yielded significant difference in condyle positions among asymptomatic, myalgia, derangement, and arthrosis group of T.M.J. disorders. The author obtained sagittal linear tomograms of right and left T.M.Js. of 36 asymptomatic, 22 myalgia, 54 derangement, and 31 arthrosis patients taken at serial lateral, central, and medial sections in the intercuspal position after submentovertex radiographs analyzed. With the dual linear measurements of the posterior and anterior interarticular space, condyle positions were mathematically expressed as proportion. All data from these analysis was recorded and processed statistically. The results were obtained as follows: 1. In asymptomatic group, radiographically concentric condyle position was found in 50.0% to 65.4% of subjects, with a substance range of variability. No significant differences existed between men and women and also between right and left T.M.Js. for condyle position. 2. In women, significant difference for mean condyle position of left lateral section of each diagnostic category existed between derangement and myalgia groups (P< .05). Also that of left central section existed between derangement and myalgia group, and that of left medial section existed between derangement and myalgia groups (P< . 05). 3. In main-symptom side, condyle position in myalgia group was more concentric, and condyle position in derangement and group was more posterior. This showed significant differences between derangement and myalgia groups in lateral, central, and medial sections of main symptom side, and only between derangement and myalgia groups in central section of contra-lateral sides (P< .05). Condyle position in arthrosis group was broadly distributed among all positions. 4. In contra-lateral side, significant difference for mean condyle position of central section of each symptomatic group existed between derangement and myalgia group (P< .05

A tomographic study of the condyle position in temporomandibular disorders

Energy Technology Data Exchange (ETDEWEB)

Choi, Sung Youn; Ryu, Young Kyu [Dept. of Oral Radiology, College of Dentistry, Yonsei University, Seoul (Korea, Republic of)

1988-11-15

The aim of this study was to determine whether T.M.J. tomographic examination yielded significant difference in condyle positions among asymptomatic, myalgia, derangement, and arthrosis group of T.M.J. disorders. The author obtained sagittal linear tomograms of right and left T.M.Js. of 36 asymptomatic, 22 myalgia, 54 derangement, and 31 arthrosis patients taken at serial lateral, central, and medial sections in the intercuspal position after submentovertex radiographs analyzed. With the dual linear measurements of the posterior and anterior interarticular space, condyle positions were mathematically expressed as proportion. All data from these analysis was recorded and processed statistically. The results were obtained as follows: 1. In asymptomatic group, radiographically concentric condyle position was found in 50.0% to 65.4% of subjects, with a substance range of variability. No significant differences existed between men and women and also between right and left T.M.Js. for condyle position. 2. In women, significant difference for mean condyle position of left lateral section of each diagnostic category existed between derangement and myalgia groups (P< .05). Also that of left central section existed between derangement and myalgia group, and that of left medial section existed between derangement and myalgia groups (P< . 05). 3. In main-symptom side, condyle position in myalgia group was more concentric, and condyle position in derangement and group was more posterior. This showed significant differences between derangement and myalgia groups in lateral, central, and medial sections of main symptom side, and only between derangement and myalgia groups in central section of contra-lateral sides (P< .05). Condyle position in arthrosis group was broadly distributed among all positions. 4. In contra-lateral side, significant difference for mean condyle position of central section of each symptomatic group existed between derangement and myalgia group (P< .05

Positive random fields for modeling material stiffness and compliance

DEFF Research Database (Denmark)

Hasofer, Abraham Michael; Ditlevsen, Ove Dalager; Tarp-Johansen, Niels Jacob

1998-01-01

Positive random fields with known marginal properties and known correlation function are not numerous in the literature. The most prominent example is the log\\-normal field for which the complete distribution is known and for which the reciprocal field is also lognormal. It is of interest to supp...

Data-driven importance distributions for articulated tracking

DEFF Research Database (Denmark)

Hauberg, Søren; Pedersen, Kim Steenstrup

2011-01-01

We present two data-driven importance distributions for particle filterbased articulated tracking; one based on background subtraction, another on depth information. In order to keep the algorithms efficient, we represent human poses in terms of spatial joint positions. To ensure constant bone le...... filter, where they improve both accuracy and efficiency of the tracker. In fact, they triple the effective number of samples compared to the most commonly used importance distribution at little extra computational cost....

Position Mooring Control Based on a Structural Reliability Criterion

DEFF Research Database (Denmark)

Fang, Shaoji; Leira, Bernt J.; Blanke, Mogens

2013-01-01

is achieved using structural reliability indices in a cost function, where both the mean mooring-line tension and dynamic effects are considered. An optimal set-point is automatically produced without need for manual interaction. The parameters of the extreme value distribution are calculated on-line thereby...... mooring lines simultaneously from exceeding a stress threshold, this paper suggests a new algorithm to determine the reference position and an associated control system. The safety of each line is assessed through a structural reliability index. A reference position where all mooring lines are safe...

The effect of merger and consolidation activities on the efficiency of electricity distribution regions in Turkey

International Nuclear Information System (INIS)

Çelen, Aydın

2013-01-01

In this study, we analyze the efficiency performances of Turkish electricity distribution companies throughout 2002 and 2009 in the stochastic frontier analysis (SFA) framework. Our more specific goal is to measure how the efficiency performances of the electricity distribution regions were affected by the mergers between distribution regions occurred in 2005. The results demonstrate that efficiencies of the companies serving to mostly the residential customers are higher than those of other companies. However, the positive impact of residential customers on the efficiencies decreased significantly following the mergers between electricity distribution companies. In contrast, the positive impact of higher customer density on efficiency also decreased, but insignificantly following the restructuring activities in the market in 2005. Our study also witnesses that the positive impact of the mergers on the efficiencies decreases as the proportion of sales to residential customers in regions increases. In contrast, the restructuring activities of 2005 increased equally the efficiencies of the companies serving in the regions with higher and lower customer densities. - Highlights: • We analyze efficiency performances of Turkish electricity distribution companies. • The efficiencies of companies serving to mostly residential customers are higher. • Positive impact of residential customers on the efficiencies dropped after mergers. • Positive impact of customer density also decreased, but insignificantly. • Positive impact of mergers on efficiency decreases as sales to residents increase

Distributed control network for optogenetic experiments

Science.gov (United States)

Kasprowicz, G.; Juszczyk, B.; Mankiewicz, L.

2014-11-01

Nowadays optogenetic experiments are constructed to examine social behavioural relations in groups of animals. A novel concept of implantable device with distributed control network and advanced positioning capabilities is proposed. It is based on wireless energy transfer technology, micro-power radio interface and advanced signal processing.

Net photosynthesis in Sphagnum mosses has increased in response to the last century's 100 ppm increase in atmospheric CO2

Science.gov (United States)

Serk, Henrik; Nilsson, Mats; Schleucher, Jurgen

2017-04-01

Peatlands store >25% of the global soil C pool, corresponding to 1/3 of the contemporary CO2-C in the atmosphere. The majority of the accumulated peat is made up by remains of Sphagnum peat mosses. Thus, understanding how various Sphagnum functional groups respond, and have responded, to increasing atmospheric CO2 and temperature constitutes a major challenge for our understanding of the role of peatlands under a changing climate. We have recently demonstrated (Ehlers et al., 2015, PNAS) that the abundance ratio of two deuterium isotopomers (molecules carrying D at specific intramolecular positions, here D6R/S) of photosynthetic glucose reflects the ratio of oxygenation to carboxylation metabolic fluxes at Rubisco. The photosynthetic glucose is prepared from various plant carbohydrates including cellulose. This finding has been established in CO2 manipulation experiments and observed in carbohydrate derived glucose isolated from herbarium samples of all investigated C-3 species. The isotopomer ratio is connected to specific enzymatic processes thus allowing for mechanistic implicit interpretations. Here we demonstrate a clear increase in net photosynthesis of Sphagnum fuscum in response to the increase of 100 ppm CO2 during the last century as deduced from analysis on S. fuscum remains from peat cores. The D6R/S ratio declines from bottom to top in peat cores, indicating CO2-driven reduction of photorespiration in contemporary moss biomass. In contrast to the hummock-forming S. fuscum, hollow-growing species, e.g. S. majus did not show this response or gave significantly weaker response, suggesting important ecological consequences of rising CO2 on peatland ecosystem services. We hypothesize that photosynthesis in hollow-growing species under water saturation is fully or partly disconnected from the atmospheric CO2 partial pressure and thus showing weaker or no response to increased atmospheric CO2. To further test the field observations we grow both hummock and

Acquisition of multiple prior distributions in tactile temporal order judgment

Directory of Open Access Journals (Sweden)

Yasuhito eNagai

2012-08-01

Full Text Available The Bayesian estimation theory proposes that the brain acquires the prior distribution of a task and integrates it with sensory signals to minimize the effect of sensory noise. Psychophysical studies have demonstrated that our brain actually implements Bayesian estimation in a variety of sensory-motor tasks. However, these studies only imposed one prior distribution on participants within a task period. In this study, we investigated the conditions that enable the acquisition of multiple prior distributions in temporal order judgment (TOJ of two tactile stimuli across the hands. In Experiment 1, stimulation intervals were randomly selected from one of two prior distributions (biased to right hand earlier and biased to left hand earlier in association with color cues (green and red, respectively. Although the acquisition of the two priors was not enabled by the color cues alone, it was significant when participants shifted their gaze (above or below in response to the color cues. However, the acquisition of multiple priors was not significant when participants moved their mouths (opened or closed. In Experiment 2, the spatial cues (above and below were used to identify which eye position or retinal cue position was crucial for the eye-movement-dependent acquisition of multiple priors in Experiment 1. The acquisition of the two priors was significant when participants moved their gaze to the cues (i.e., the cue positions on the retina were constant across the priors, as well as when participants did not shift their gazes (i.e., the cue positions on the retina changed according to the priors. Thus, both eye and retinal cue positions were effective in acquiring multiple priors. Based on previous neurophysiological reports, we discuss possible neural correlates that contribute to the acquisition of multiple priors.

Electron spray ionization mass spectrometry and 2D 31P NMR for monitoring 18O/16O isotope exchange and turnover rates of metabolic oligophosphates

International Nuclear Information System (INIS)

Nemutlu, Emirhan; Juranic, Nenad; Macura, Slobodan; Zhang, Song; Terzic, Andre; Dzeja, Petras P.; Ward, Lawrence E.; Dutta, Tumpa; Nair, K.S.

2012-01-01

A new method was here developed for the determination of 18 O-labeling ratios in metabolic oligophosphates, such as ATP, at different phosphoryl moieties (α-, β-, and γ-ATP) using sensitive and rapid electrospray ionization mass spectrometry (ESI-MS). The ESI-MS-based method for monitoring of 18 O/ 16 O exchange was validated with gas chromatography-mass spectrometry and 2D 31 P NMR correlation spectroscopy, the current standard methods in labeling studies. Significant correlation was found between isotopomer selective 2D 31 P NMR spectroscopy and isotopomer less selective ESI-MS method. Results demonstrate that ESI-MS provides a robust analytical platform for simultaneous determination of levels, 18 O-labeling kinetics and turnover rates of α-, β-, and γ-phosphoryls in ATP molecule. Such method is advantageous for large scale dynamic phosphometabolomic profiling of metabolic networks and acquiring information on the status of probed cellular energetic system. (orig.)

The country of distribution effect on the brand attitude change

Directory of Open Access Journals (Sweden)

José Mauro da Costa Hernandez

2014-08-01

Full Text Available This research investigates the country of distribution effect on the change of attitudes towards a brand. Country of distribution is defined as the results (positive or negative obtained by a brand when it communicates to be distributed in a foreigner locale. The results of three experiments demonstrate that the country of distribution effect is higher when the country is a traditional manufacturer (vs. non-traditional manufacturer of the brand’s product category. Further, the country of distribution effect is higher for high quality (vs. low quality brands and is moderated by the perceived success of the brand in the distribution country.

Effects of Positioning Uncertainty and Breathing on Dose Delivery and Radiation Pneumonitis Prediction in Breast Cancer

International Nuclear Information System (INIS)

Mavroidis, Panayiotis; Axelsson, Sofie; Hyoedynmaa, Simo; Rajala, Juha; Pitkaenen, Maunu A.; Lind, Bengt K.; Brahme, Anders

2002-01-01

The quality of the radiation therapy delivered in the treatment of breast cancer is susceptible to setup errors and organ motion uncertainties. For 60 breast cancer patients (24 resected with negative node involvement, 13 resected with positive node involvement and 23 ablated) who were treated with three different irradiation techniques, these uncertainties are simulated. The delivered dose distributions in the lung were recalculated taking positioning uncertainty and breathing effects into account. In this way the real dose distributions delivered to the patients are more closely determined. The positioning uncertainties in the anteroposterior (AP) and the craniocaudal (CC) directions are approximated by Gaussian distributions based on the fact that setup errors are random. Breathing is assumed to have a linear behavior because of the chest wall movement during expiration and inspiration. The combined frequency distribution of the positioning and breathing distributions is obtained by convolution. By integrating the convolved distribution over a number of intervals, the positions and the weights of the fields that simulate the original 'effective fields' are calculated. Opposed tangential fields are simulated by a set of 5 pairs of fields in the AP direction and 3 such sets in the CC direction. Opposed AP + PA fields are simulated by a set of 3 pairs of fields in the AP direction and 3 such sets in the CC direction. Single frontal fields are simulated by a set of 5 fields. In radiotherapy for breast cancer, the lung is often partly within the irradiated volume even though it is a sensitive organ at risk. The influence of the deviation in the dose delivered by the original and the adjusted treatment plans on the clinical outcome is estimated by using the relative seriality model and the biologically effective uniform dose concept. Radiation pneumonitis is used as the clinical endpoint for lung complications. The adjusted treatment plans show larger lung

Positive mental health and well-being among a third level student population.

LENUS (Irish Health Repository)

Davoren, Martin P

2013-01-01

Much research on the health and well-being of third level students is focused on poor mental health leading to a dearth of information on positive mental health and well-being. Recently, the Warwick Edinburgh Mental Well-being scale (WEMWBS) was developed as a measurement of positive mental health and well-being. The aim of this research is to investigate the distribution and determinants of positive mental health and well-being in a large, broadly representative sample of third level students using WEMWBS.

slide positivity rate of malaria among patients attending two ...

African Journals Online (AJOL)

DR. AMINU

Key words: malaria, slide positivity rate, Kano metropolis. INTRODUCTION. Malaria has a worldwide distribution, affecting people of all ages, with an enormous burden amounting to. 300-500 million clinical cases per year, 80% of which occur in Africa (Lucas & Gills, 2003). Globally ten (10) new cases of malaria occur every ...

Implausibility of the vibrational theory of olfaction.

Science.gov (United States)

Block, Eric; Jang, Seogjoo; Matsunami, Hiroaki; Sekharan, Sivakumar; Dethier, Bérénice; Ertem, Mehmed Z; Gundala, Sivaji; Pan, Yi; Li, Shengju; Li, Zhen; Lodge, Stephene N; Ozbil, Mehmet; Jiang, Huihong; Penalba, Sonia F; Batista, Victor S; Zhuang, Hanyi

2015-05-26

The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of these compounds in vitro. Furthermore, the mouse (methylthio)methanethiol-recognizing receptor, MOR244-3, as well as other selected human and mouse ORs, responded similarly to normal, deuterated, and (13)C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d30 lacks the 1,380- to 1,550-cm(-1) IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of nonodorant molecular vibrational modes. These and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.

The Research of Indoor Positioning Based on Double-peak Gaussian Model

Directory of Open Access Journals (Sweden)

Lina Chen

2014-04-01

Full Text Available Location fingerprinting using Wi-Fi signals has been very popular and is a well accepted indoor positioning method. The key issue of the fingerprinting approach is generating the fingerprint radio map. Limited by the practical workload, only a few samples of the received signal strength are collected at each reference point. Unfortunately, fewer samples cannot accurately represent the actual distribution of the signal strength from each access point. This study finds most Wi- Fi signals have two peaks. According to the new finding, a double-peak Gaussian arithmetic is proposed to generate a fingerprint radio map. This approach requires little time to receive WiFi signals and it easy to estimate the parameters of the double-peak Gaussian function. Compared to the Gaussian function and histogram method to generate a fingerprint radio map, this method better approximates the occurrence signal distribution. This paper also compared the positioning accuracy using K-Nearest Neighbour theory for three radio maps, the test results show that the positioning distance error utilizing the double-peak Gaussian function is better than the other two methods.

Sleep positions and nocturnal body movements based on free-living accelerometer recordings

DEFF Research Database (Denmark)

Skarpsno, Eivind Schjelderup; Mork, Paul Jarle; Nilsen, Tom Ivar Lund

2017-01-01

Background: In order to establish normative values for body positions and movements during sleep, the objective of this study was to explore the distribution of sleep positions and extent of nocturnal body moments and the association with sex, age, body-mass index (BMI), smoking, alcohol......), but more arm, thigh, and upper-back movements compared to normal-weight participants. Smokers had fewer shifts in body position than nonsmokers (-0.27, 95% CI -0.4 to -0.13). Conclusion: The predominant sleep position in adults is on the side. This preference increases with age and BMI. The extent...

Distribution of multi-resistant Gram-negative versus Gram-positive bacteria in the hospital inanimate environment.

Science.gov (United States)

Lemmen, S W; Häfner, H; Zolldann, D; Stanzel, S; Lütticken, R

2004-03-01

We prospectively studied the difference in detection rates of multi-resistant Gram-positive and multi-resistant Gram-negative bacteria in the inanimate environment of patients harbouring these organisms. Up to 20 different locations around 190 patients were surveyed. Fifty-four patients were infected or colonized with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE) and 136 with multi-resistant Gram-negative bacteria. The environmental detection rate for MRSA or VRE was 24.7% (174/705 samples) compared with 4.9% (89/1827 samples) for multi-resistant Gram-negative bacteria (PGram-positive bacteria were isolated more frequently than Gram-negatives from the hands of patients (PGram-positive and Gram-negative isolates. Our results suggest that the inanimate environment serves as a secondary source for MRSA and VRE, but less so for Gram-negative bacteria. Thus, strict contact isolation in a single room with complete barrier precautions is recommended for MRSA or VRE; however, for multi-resistant Gram-negative bacteria, contact isolation with barrier precautions for close contact but without a single room seems sufficient. This benefits not only the patients, but also the hospital by removing some of the strain placed on already over-stretched resources.

Collisional relaxation of electron tail distribution

International Nuclear Information System (INIS)

Yamagiwa, Mitsuru; Okamoto, Masao.

1985-05-01

Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

Distribution, vertical position and ecological implications of shallow gas in Bahía Blanca estuary (Argentina)

Science.gov (United States)

Bravo, M. E.; Aliotta, S.; Fiori, S.; Ginsberg, S.

2018-03-01

There has been a growing interest in the study of shallow gas due its importance in relation to the marine environment, climate change and human activities. In Bahía Blanca estuary, Argentina, shallow gas has a wide distribution. Acoustic turbidity and blanking are the main seismic evidence for the presence of shallow gas in the estuary. The former prevails in the inner sector of the estuary where gas is either near or in contact with the seabed. Gas deposits are generally associated with paleochannels corresponding to the Holocene paleodeltaic environment. Distribution studies of shallow gas in this estuary are necessary because its presence implies not only a geological risk for harbor activities but also because it may have noxious effects on the marine ecosystem, mainly on benthic communities. The comparison of benthic communities at a gas site (GS) with those at a control site (CS) indicated that gas could generate impoverishment in terms of individuals' abundance (GS: N = 357; CS: N = 724). Also, diversity indices showed great differences in the community structure at each site. This indicates that methane gas may act as a natural disturbance agent in estuarine ecosystems. The presence of gas in seabed sediments must therefore be taken into account when distribution studies are conducted of estuarine benthic communities.

Position detectors, methods of detecting position, and methods of providing positional detectors

Science.gov (United States)

Weinberg, David M.; Harding, L. Dean; Larsen, Eric D.

2002-01-01

Position detectors, welding system position detectors, methods of detecting various positions, and methods of providing position detectors are described. In one embodiment, a welding system positional detector includes a base that is configured to engage and be moved along a curved surface of a welding work piece. At least one position detection apparatus is provided and is connected with the base and configured to measure angular position of the detector relative to a reference vector. In another embodiment, a welding system positional detector includes a weld head and at least one inclinometer mounted on the weld head. The one inclinometer is configured to develop positional data relative to a reference vector and the position of the weld head on a non-planar weldable work piece.

Tyrosine hydroxylase positive nerves and mast cells in the porcine gallbladder

Directory of Open Access Journals (Sweden)

I. Stefanov

2017-03-01

Full Text Available The aim of this study was to detect the localisation of tyrosine hydroxylase (TH positive nerve fibres (THN and distribution of tyrosine hydroxylase positive mast cells (THMC in the wall of porcine gallbladder. THN were observed as single fibres, nerve fibres forming perivascular plexuses and nerve fibres grouped within the nerve fascicles. In the gallbladder`s fundus, body and neck, the TH+ fibres formed mucosal, muscular and serosal nonganglionated nerve plexuses. Toluidine blue (TB staining was used to confirm that the TH positive cells were mast cells. The number of THMC in the propria of gallbladder`s fundus, body and neck was significantly higher than in the muscular and serosal layers in both genders. The number of mast cells in the musculature was higher than in the serosa. The density and location of the THMC were similar to the TB positive (with gamma meta-chromasia mast cells in both males and females, and statistically significant difference was not established. In conclusion, original data concerning the existence and localisation of catecholaminergic nerves and THMC distribution in the porcine gallbladder’s wall are presented. The results could con-tribute to the body of knowledge of functional communication between autonomic nerves and mast cells in the gallbladder.

Modeling Method for Increased Precision and Scope of Directly Measurable Fluxes at a Genome-Scale

DEFF Research Database (Denmark)

McCloskey, Douglas; Young, Jamey D.; Xu, Sibei

2016-01-01

pathways of traditional MFA models and also covers the additional pathways of purine, pyrimidine, isoprenoid, methionine, riboflavin, coenzyme A, and folate, as well as other biosynthetic pathways. When evaluating the iDM2014 using a set of measured intracellular intermediate and cofactor mass isotopomer...

Mechanism and Stereoselectivity of Zeolite-catalysed Sugar Isomerisation in Alcohols

DEFF Research Database (Denmark)

Shunmugavel, Saravanamurugan; Riisager, Anders; Taarning, Esben

2016-01-01

Glucose isomerisation to fructose can occur by different pathways and the mechanism of zeolite-catalysed glucose isomerisation in methanol has remained incompletely understood. Herein, the mechanism is studied using an 1H-13C HSQC NMR assay resolving different fructose isotopomers. We find that z...

A machine learning approach to the accurate prediction of multi-leaf collimator positional errors

Science.gov (United States)

Carlson, Joel N. K.; Park, Jong Min; Park, So-Yeon; In Park, Jong; Choi, Yunseok; Ye, Sung-Joon

2016-03-01

Discrepancies between planned and delivered movements of multi-leaf collimators (MLCs) are an important source of errors in dose distributions during radiotherapy. In this work we used machine learning techniques to train models to predict these discrepancies, assessed the accuracy of the model predictions, and examined the impact these errors have on quality assurance (QA) procedures and dosimetry. Predictive leaf motion parameters for the models were calculated from the plan files, such as leaf position and velocity, whether the leaf was moving towards or away from the isocenter of the MLC, and many others. Differences in positions between synchronized DICOM-RT planning files and DynaLog files reported during QA delivery were used as a target response for training of the models. The final model is capable of predicting MLC positions during delivery to a high degree of accuracy. For moving MLC leaves, predicted positions were shown to be significantly closer to delivered positions than were planned positions. By incorporating predicted positions into dose calculations in the TPS, increases were shown in gamma passing rates against measured dose distributions recorded during QA delivery. For instance, head and neck plans with 1%/2 mm gamma criteria had an average increase in passing rate of 4.17% (SD  =  1.54%). This indicates that the inclusion of predictions during dose calculation leads to a more realistic representation of plan delivery. To assess impact on the patient, dose volumetric histograms (DVH) using delivered positions were calculated for comparison with planned and predicted DVHs. In all cases, predicted dose volumetric parameters were in closer agreement to the delivered parameters than were the planned parameters, particularly for organs at risk on the periphery of the treatment area. By incorporating the predicted positions into the TPS, the treatment planner is given a more realistic view of the dose distribution as it will truly be

Comparison between two bivariate Poisson distributions through the ...

African Journals Online (AJOL)

These two models express themselves by their probability mass function. ... To remedy this problem, Berkhout and Plug proposed a bivariate Poisson distribution accepting the correlation as well negative, equal to zero, that positive.

Ion energy and angular distributions in inductively coupled Argon RF discharges

International Nuclear Information System (INIS)

Woodworth, J.R.; Riley, M.E.; Meister, D.C.

1996-03-01

We report measurements of the energies and angular distributions of positive ions in an inductively coupled argon plasma in a GEC reference cell. Use of two separate ion detectors allowed measurement of ion energies and fluxes as a function of position as well as ion angular distributions on the discharge centerline. The inductive drive on our system produced high plasma densities (up to 10 12 /cm 3 electron densities) and relatively stable plasma potentials. As a result, ion energy distributions typically consisted of a single feature well separated from zero energy. Mean ion energy was independent of rf power and varied inversely with pressure, decreasing from 29 eV to 12 eV as pressure increased form 2.4 m Torr to 50 mTorr. Half-widths of the ion angular distributions in these experiments varied from 5 degrees to 12.5 degrees, or equivalently, transverse temperatures varied form 0.2 to 0.5 eV with the distributions broadening as either pressure or RF power were increased

Distributed Leadership in a Low-Carbon City Agenda

Directory of Open Access Journals (Sweden)

Azalia Mohamed

2016-07-01

Full Text Available This paper uses Spillane’s (2001 theory and Gronn’s (2000 concerted efforts approach to examine distributed leadership in a low-carbon city agenda. The main purpose of the paper is to find empirical evidence of a relationship between distributed leadership and the achievement of the agenda. Eight constructs emerged that informed our understanding of distributed leadership dimensions within the low-carbon city framework: vision, organizational framework, organizational culture, consensus, instructional programs, expertise, team leader leadership, and team member leadership. The evidence shows that there is a positive relationship between distributed leadership and the outcome of the low-carbon city agenda, and that a dispersed pattern in distributing leadership is required to enhance community engagement. The findings also suggest that an organizational culture that facilitates multiple sources of leadership may largely contribute to the effectiveness of distributed leadership practices in realizing the low-carbon city agenda.

Radiation distribution sensing with normal optical fiber

CERN Document Server

Kawarabayashi, J; Naka, R; Uritani, A; Watanabe, K I; Iguchi, T; Tsujimura, N

2002-01-01

The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length (10m-100m) and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The characteristics of this monitor to beta particles, gamma rays and fast neutrons were obtained. The spatial resolutions for beta particles ( sup 9 sup 0 Sr sup - sup 9 sup 0 Y), gamma rays ( sup 1 sup 3 sup 7 Cs) and D-T neutrons were 30 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the gamma rays and D-T neutrons were 0.11%, 1.6x10 sup - sup 5 % and 5.4x10 sup - sup 4 %, respectively. The effective attenuation length of the detection efficiency was 18m. New principle of the position sensing based on spectroscopic analysis was also proposed. A preliminary test showed that the spectrum observed at the end of the fiber depended on the position of the irradiated point. This fact shows that t...

Social Media Ecology in Distributed Workplaces

DEFF Research Database (Denmark)

Giuffrida, Rosalba; Dittrich, Yvonne

2011-01-01

In this position paper, we discuss about methods currently adopted for research- ing the use of social media in distributed workplace. We have extensively reviewed previ- ous empirical studies through an ongoing Systematic Mapping Study focused on the use of social media in distributed teams; from...... the review, we realized that research is mainly per- formed through a mix of qualitative and quantitative methods and that each study usually fo- cuses on one specific kind social media at a time. We believe that the social media ecology should be researched as a whole and in relationship with the physical...

Characterization of Stationary Distributions of Reflected Diffusions

Science.gov (United States)

2014-01-01

operations research to finance and mathemat- ical physics , and their stationary distributions often serve to characterize or approximate important...REFERENCES [1] Atar , R., Budhiraja, A. and Dupuis, P. (2001). On positive recurrence of constrained diffusion processes. Ann. Probab., 29 No. 2, 979-1000

Distortion of plasma due to installation of an orifice in helium discharge positive column

International Nuclear Information System (INIS)

Moslehi- Fard, M.; Bidadi, H.; Khorram, S.; Sobhanian, S.; Muradov, A.H.; Jallali, H.; Shirin Pour, M.

2003-01-01

Complicated potential structure formed at a constriction of positive column of a DC discharge with heated cathode in He at low discharge currents is investigated. According to the potential structure, electrons and ions are accelerated by the electric field and their energy distribution functions acquire multi humped shapes. Additional maximums on distribution function quickly disappear due to collisions and radial losses. The nature of current passing through the potential structure is cleared up on the base of measured distributions. Attempt was made to calculate potential drop in DL tacking into account electron energy distribution variations

Phylogenetic distribution of intron positions in alpha-amylase genes of bilateria suggests numerous gains and losses.

Directory of Open Access Journals (Sweden)

Jean-Luc Da Lage

Full Text Available Most eukaryotes have at least some genes interrupted by introns. While it is well accepted that introns were already present at moderate density in the last eukaryote common ancestor, the conspicuous diversity of intron density among genomes suggests a complex evolutionary history, with marked differences between phyla. The question of the rates of intron gains and loss in the course of evolution and factors influencing them remains controversial. We have investigated a single gene family, alpha-amylase, in 55 species covering a variety of animal phyla. Comparison of intron positions across phyla suggests a complex history, with a likely ancestral intronless gene undergoing frequent intron loss and gain, leading to extant intron/exon structures that are highly variable, even among species from the same phylum. Because introns are known to play no regulatory role in this gene and there is no alternative splicing, the structural differences may be interpreted more easily: intron positions, sizes, losses or gains may be more likely related to factors linked to splicing mechanisms and requirements, and to recognition of introns and exons, or to more extrinsic factors, such as life cycle and population size. We have shown that intron losses outnumbered gains in recent periods, but that "resets" of intron positions occurred at the origin of several phyla, including vertebrates. Rates of gain and loss appear to be positively correlated. No phase preference was found. We also found evidence for parallel gains and for intron sliding. Presence of introns at given positions was correlated to a strong protosplice consensus sequence AG/G, which was much weaker in the absence of intron. In contrast, recent intron insertions were not associated with a specific sequence. In animal Amy genes, population size and generation time seem to have played only minor roles in shaping gene structures.

Electron-beam-charged dielectrics: Internal charge distribution

Science.gov (United States)

Beers, B. L.; Pine, V. W.

1981-01-01

Theoretical calculations of an electron transport model of the charging of dielectrics due to electron bombardment are compared to measurements of internal charge distributions. The emphasis is on the distribution of Teflon. The position of the charge centroid as a function of time is not monotonic. It first moves deeper into the material and then moves back near to the surface. In most time regimes of interest, the charge distribution is not unimodal, but instead has two peaks. The location of the centroid near saturation is a function of the incident current density. While the qualitative comparison of theory and experiment are reasonable, quantitative comparison shows discrepancies of as much as a factor of two.

Effect of nasal continuous and biphasic positive airway pressure on lung volume in preterm infants

NARCIS (Netherlands)

Miedema, Martijn; van der Burg, Pauline S.; Beuger, Sabine; de Jongh, Frans H.; Frerichs, Inez; van Kaam, Anton H.

2013-01-01

To monitor regional changes in end-expiratory lung volume (EELV), tidal volumes, and their ventilation distribution during different levels of nasal continuous positive airway pressure (nCPAP) and nasal biphasic positive airway pressure (BiPAP) in stable preterm infants. By using electrical

Settling-velocity specific SOC distribution on hillslopes

DEFF Research Database (Denmark)

Hu, Yaxian; Berhe, Asmeret Asefaw; Fogel, Marilyn L.

The net effect of soil erosion by water, as a sink or source of atmospheric CO2, is determined by the spatial (re-)distribution and stability of eroded soil organic carbon (SOC). The depositional position of eroded SOC is a function of the transport distances of soil fractions where the SOC...... fractions. Eroding sandy soils and sediment were sampled after a series of rainfall events along a slope on a freshly seeded cropland in Jutland, Denmark. All the soil samples were fractionated into five settling classes using a settling tube apparatus. The spatial distribution of soil settling classes...... shows a coarsening effect immediately below the eroding slope, followed by a fining trend at the slope tail. The 13C values of soil fractions were more positive at the footslope than on the slope shoulder or at the slope tail, suggesting enhanced decomposition rate of fresh SOC input at the footslope...

Community structure informs species geographic distributions

KAUST Repository

Montesinos-Navarro, Alicia

2018-05-23

Understanding what determines species\\' geographic distributions is crucial for assessing global change threats to biodiversity. Measuring limits on distributions is usually, and necessarily, done with data at large geographic extents and coarse spatial resolution. However, survival of individuals is determined by processes that happen at small spatial scales. The relative abundance of coexisting species (i.e. \\'community structure\\') reflects assembly processes occurring at small scales, and are often available for relatively extensive areas, so could be useful for explaining species distributions. We demonstrate that Bayesian Network Inference (BNI) can overcome several challenges to including community structure into studies of species distributions, despite having been little used to date. We hypothesized that the relative abundance of coexisting species can improve predictions of species distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to incorporate community structure into Species Distribution Models (SDMs), alongside environmental information. Information on species associations improved SDM predictions of community structure and species distributions moderately, though for some habitat specialists the deviance explained increased by up to 15%. We demonstrate that most species associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a proxy for local ecological processes. Our study shows that Bayesian Networks, when interpreted carefully, can be used to include local conditions into measurements of species\\' large-scale distributions, and this information can improve the predictions of species distributions.

Position-sensitive proportional counter with low-resistance metal-wire anode

International Nuclear Information System (INIS)

Kopp, M.K.

1980-01-01

A position-sensitive proportional counter circuit is provided which uses a conventional (low-resistance, metal-wire anode) proportional counter for spatial resolution of an ionizing event along the anode of the counther. A pair of specially designed activecapacitance preamplifiers terminate the anode ends wherein the anode is treated as an RC line. The preamplifiers act as stabilized active capacitance loads and each is composed of a series-feedback, lownoise amplifier, a unity-gain, shunt-feedback amplifier whose output is connected through a feedback capacitor to the series-feedback amplifier input. The stabilized capacitance loading of the anode allows distributed RC-line position encoding and subsequent time difference decoding by sensing the difference in rise times of pulses at te anode ends where the difference is primarily in response to the distributed capacitance along the anode. This allows the use of lower resistance wire anodes for spatial radiation detection which simplifies the counter construction and handling of the anodes, and stabilizes the anode resistivity at high count rates

Distributive justice and infertility treatment in Canada.

Science.gov (United States)

Nisker, Jeff

2008-05-01

An exploration of distributive justice in Canadian infertility treatment requires the integration of ethical, clinical, and economic principles. In 1971, American philosopher John Rawls proposed a theoretical model for fair decision-making in which "rational" and "self-interested" citizens are behind a "veil of ignorance" with respect to both their own position and the position of other decision-makers. Rawls proposed that these self-interested decision-makers, fearing that they are among the least advantaged persons who could be affected by the decision, will agree only upon rules that encode equality of opportunity and that bestow the greatest benefit on the least advantaged citizens. Regarding health policy decision-making, Rawls' model is best illustrated by Canadian philosopher Warren Bourgeois in his panel of "volunteers." These rational and self-interested volunteers receive an amnestic drug that renders them unaware of their health, social, and financial position, but they know that they are representative of diverse spheres of citizens whose well-being will be affected by their decision. After describing fair decision-making, Bourgeois considers the lack of a distributive justice imperative in Canada's Assisted Human Reproduction Act, in contrast to legislation in European nations and Australia, summarizes the economic and clinical considerations that must be provided to the decision-makers behind the "veil of ignorance" for fair decisions to occur, and considers altruism in relation to equality of access. He concludes by noting that among countries with legislation governing assisted reproduction Canada is alone in having legislation that is void of distributive justice in providing access to clinically appropriate infertility care.

Measuring distributed leadership agency in a hospital context

DEFF Research Database (Denmark)

Jønsson, Thomas; Unterrainer, Christine; Jeppesen, Hans Jeppe

2016-01-01

and valid quantitative instrument that measures how much employees’ at all hierarchical levels are involved in concrete leadership activities in the hospital context. Taking a normative perspective we could show that Distributed Leadership – measured with the DLA-questionnaire – has positive effects......Purpose: The purpose of this study is to develop and validate an instrument that can measure Distributed Leadership as employees’ active participation in distributed leadership tasks. We designate this as the Distributed Leadership Agency (DLA). Methodology: Data were collected throughout all......, discriminant and convergent validity, and ANOVAs were applied to analyze group differences in DLA. Findings: The identified uni-dimensional questionnaire consists of seven items, as it is different from, but associated with, empowering leadership, organizational influence, attitude to participation and trust...

Cross-coherent vector sensor processing for spatially distributed glider networks.

Science.gov (United States)

Nichols, Brendan; Sabra, Karim G

2015-09-01

Autonomous underwater gliders fitted with vector sensors can be used as a spatially distributed sensor array to passively locate underwater sources. However, to date, the positional accuracy required for robust array processing (especially coherent processing) is not achievable using dead-reckoning while the gliders remain submerged. To obtain such accuracy, the gliders can be temporarily surfaced to allow for global positioning system contact, but the acoustically active sea surface introduces locally additional sensor noise. This letter demonstrates that cross-coherent array processing, which inherently mitigates the effects of local noise, outperforms traditional incoherent processing source localization methods for this spatially distributed vector sensor network.

Weight Distribution for Non-binary Cluster LDPC Code Ensemble

Science.gov (United States)

Nozaki, Takayuki; Maehara, Masaki; Kasai, Kenta; Sakaniwa, Kohichi

In this paper, we derive the average weight distributions for the irregular non-binary cluster low-density parity-check (LDPC) code ensembles. Moreover, we give the exponential growth rate of the average weight distribution in the limit of large code length. We show that there exist $(2,d_c)$-regular non-binary cluster LDPC code ensembles whose normalized typical minimum distances are strictly positive.

Two new bivariate zero-inflated generalized Poisson distributions with a flexible correlation structure

Directory of Open Access Journals (Sweden)

Chi Zhang

2015-05-01

Full Text Available To model correlated bivariate count data with extra zero observations, this paper proposes two new bivariate zero-inflated generalized Poisson (ZIGP distributions by incorporating a multiplicative factor (or dependency parameter λ, named as Type I and Type II bivariate ZIGP distributions, respectively. The proposed distributions possess a flexible correlation structure and can be used to fit either positively or negatively correlated and either over- or under-dispersed count data, comparing to the existing models that can only fit positively correlated count data with over-dispersion. The two marginal distributions of Type I bivariate ZIGP share a common parameter of zero inflation while the two marginal distributions of Type II bivariate ZIGP have their own parameters of zero inflation, resulting in a much wider range of applications. The important distributional properties are explored and some useful statistical inference methods including maximum likelihood estimations of parameters, standard errors estimation, bootstrap confidence intervals and related testing hypotheses are developed for the two distributions. A real data are thoroughly analyzed by using the proposed distributions and statistical methods. Several simulation studies are conducted to evaluate the performance of the proposed methods.

Sharp conditions for global stability of Lotka-Volterra systems with distributed delays

Science.gov (United States)

Faria, Teresa

We give a criterion for the global attractivity of a positive equilibrium of n-dimensional non-autonomous Lotka-Volterra systems with distributed delays. For a class of autonomous Lotka-Volterra systems, we show that such a criterion is sharp, in the sense that it provides necessary and sufficient conditions for the global asymptotic stability independently of the choice of the delay functions. The global attractivity of positive equilibria is established by imposing a diagonal dominance of the instantaneous negative feedback terms, and relies on auxiliary results showing the boundedness of all positive solutions. The paper improves and generalizes known results in the literature, namely by considering systems with distributed delays rather than discrete delays.

Double hydrogen atom transfer in lactamide radical cations via ion-neutral complexes

Science.gov (United States)

Friedrichs, Heike; McGibbon, Graham A.; Schwarz, Helmut

1996-02-01

Tandem mass spectrometry experiments on lactamide and deuterium-labelled isotopomers show that the reaction of metastable ions CH3CH(OH)CONH2·+ --> CH3CO· + HC(OH)NH2+ occurs via ion-neutral complexes. The experimental findings are complemented by density functional theory calculations.

Dynamic Infrared Thermography Study of Blood Flow Relative to Lower Limp Position

Science.gov (United States)

Stathopoulos, I.; Skouroliakou, K.; Michail, C.; Valais, I.

2015-09-01

Thermography is an established method for studying skin temperature distribution. Temperature distribution on body surface is influenced by a variety of physiological mechanisms and has been proven a reliable indicator of various physiological disorders. Blood flow is an important factor that influences body heat diffusion and skin temperature. In an attempt to validate and further elucidate thermal models characterizing the human skin, dynamic thermography of the lower limp in horizontal and vertical position was performed, using a FLIR T460 thermographic camera. Temporal variation of temperature was recorded on five distinct points of the limp. Specific points were initially cooled by the means of an ice cube and measurements of the skin temperature were obtained every 30 seconds as the skin temperature was locally reduced and afterwards restored at its initial value. The return to thermal balance followed roughly the same pattern for all points of measurement, although the heating rate was faster when the foot was in horizontal position. Thermal balance was achieved faster at the spots that were positioned on a vein passage. Our results confirm the influence of blood flow on the thermal regulation of the skin. Spots located over veins exhibit different thermal behaviour due to thermal convection through blood flow. Changing the position of the foot from vertical to horizontal, effectively affects blood perfusion as in the vertical position blood circulation is opposed by gravity.

Factors determining Gekkotan (Reptilia, Sauria distribution in Tunisia (North Africa

Directory of Open Access Journals (Sweden)

Wided Tlili

2014-12-01

Full Text Available Tunisian geckos count nine species (1 is insular relict, 1 is endemic, 2 are ubiquitous and 5 are enfeoffed. We aim to determine factors influencing their distributions. Surveys were founded on environmental divisions. Presence/absence data for 113 grids were analyzed using multivariate tools. 18 environmental variables were revealed and clustered into five factors to model species distributions. Established models were further projected on non-explored areas within Tunisian territory. The distribution of continental geckos follows an indirect bidirectional gradient; the South-northward one is physiologically stressful and the North-southward one is biologically stressful. Five biogeographic regions were established showing concordance with climatic and vegetation regionalization. The distribution of non-anthropophilic species is positively correlated to thermal amplitudes gradient. The distribution of anthropophilic taxa is positively correlated to agricultural land-use. Oasis, sebkhas and chotts are particular landscapes that disturb both distributions. Predicted areas follow the yielded distribution patterns despite some discrepancy for S. sthenodactylus. The niche characterizing shows that land use and altitude increase the probability of occurrence of H. turcicus and T. mauritanica. Alternatively, they decrease the probability of the presence of T. deserti, T. neglecta, T. tripolitanus and S. petrii. Models could also show that the absence of S. sthenodactylus in northern regions is attributed to high altitudes and cereal land-use. As to T. fascicularis, the displacement of the northern limits of its range is mostly attributed to an improvement of field investigations. Established model of its distribution shows a restricted area of probable occurrence in central Tunisia confirming its endemism.

A semi-analytical study of positive corona discharge in wire–plane electrode configuration

International Nuclear Information System (INIS)

Yanallah, K; Pontiga, F; Chen, J H

2013-01-01

Wire-to-plane positive corona discharge in air has been studied using an analytical model of two species (electrons and positive ions). The spatial distributions of electric field and charged species are obtained by integrating Gauss's law and the continuity equations of species along the Laplacian field lines. The experimental values of corona current intensity and applied voltage, together with Warburg's law, have been used to formulate the boundary condition for the electron density on the corona wire. To test the accuracy of the model, the approximate electric field distribution has been compared with the exact numerical solution obtained from a finite element analysis. A parametrical study of wire-to-plane corona discharge has then been undertaken using the approximate semi-analytical solutions. Thus, the spatial distributions of electric field and charged particles have been computed for different values of the gas pressure, wire radius and electrode separation. Also, the two dimensional distribution of ozone density has been obtained using a simplified plasma chemistry model. The approximate semi-analytical solutions can be evaluated in a negligible computational time, yet provide precise estimates of corona discharge variables. (paper)

A semi-analytical study of positive corona discharge in wire-plane electrode configuration

Science.gov (United States)

Yanallah, K.; Pontiga, F.; Chen, J. H.

2013-08-01

Wire-to-plane positive corona discharge in air has been studied using an analytical model of two species (electrons and positive ions). The spatial distributions of electric field and charged species are obtained by integrating Gauss's law and the continuity equations of species along the Laplacian field lines. The experimental values of corona current intensity and applied voltage, together with Warburg's law, have been used to formulate the boundary condition for the electron density on the corona wire. To test the accuracy of the model, the approximate electric field distribution has been compared with the exact numerical solution obtained from a finite element analysis. A parametrical study of wire-to-plane corona discharge has then been undertaken using the approximate semi-analytical solutions. Thus, the spatial distributions of electric field and charged particles have been computed for different values of the gas pressure, wire radius and electrode separation. Also, the two dimensional distribution of ozone density has been obtained using a simplified plasma chemistry model. The approximate semi-analytical solutions can be evaluated in a negligible computational time, yet provide precise estimates of corona discharge variables.

Distribution of dispersed oil phase in hydrocarbon fermentations

Energy Technology Data Exchange (ETDEWEB)

Ho, C S; Erickson, L E

1978-04-01

Recent experimental results show that the spreading coefficient frequently becomes positive when Candida lipolytica is cultivated on n-hexadecane. The effects of oil spreading at the surface of air bubbles in an airlift fermentor are examined using a mathematical model. The distribution of the oil phase with position and among the phases is determined using computer simulation. The simulation results qualitatively explain some of the experimental observations which have been previously reported.

Reliability and Inequality Measures for the Weimal Distribution

African Journals Online (AJOL)

hp

understanding the reliability of systems and their .... Using the identity given by Gradshteyn and Ryzhik (2007) for power series raised to a positive integer i, we have: (∑. ) ..... probability distributions for lifetimes of systems of components. Thesis,.

Fillers as Signs of Distributional Learning

Science.gov (United States)

Taelman, Helena; Durieux, Gert; Gillis, Steven

2009-01-01

A longitudinal analysis is presented of the fillers of a Dutch-speaking child between 1;10 and 2;7. Our analysis corroborates familiar regularities reported in the literature: most fillers resemble articles in shape and distribution, and are affected by rhythmic and positional constraints. A novel finding is the impact of the lexical environment:…

Preferences for distributional impacts of climate policy

DEFF Research Database (Denmark)

Svenningsen, Lea Skræp; Thorsen, Bo Jellesmark

for such preferences is lacking. We design a discrete choice experiment that varies how climate policies affect the income of people living in the future in three geographical regions. The experiment is implemented on a representative sample of the Danish population and preferences are modelled in a latent class model...... expresses some form of distributional preferences, but shows positive preferences for costs, suggesting that responses could be influenced by strategic behaviour and over-signalling of commitment. Our results provide support for the inclusion of social preferences regarding distributional effects of climate...

The beta Burr type X distribution properties with application.

Science.gov (United States)

Merovci, Faton; Khaleel, Mundher Abdullah; Ibrahim, Noor Akma; Shitan, Mahendran

2016-01-01

We develop a new continuous distribution called the beta-Burr type X distribution that extends the Burr type X distribution. The properties provide a comprehensive mathematical treatment of this distribution. Further more, various structural properties of the new distribution are derived, that includes moment generating function and the rth moment thus generalizing some results in the literature. We also obtain expressions for the density, moment generating function and rth moment of the order statistics. We consider the maximum likelihood estimation to estimate the parameters. Additionally, the asymptotic confidence intervals for the parameters are derived from the Fisher information matrix. Finally, simulation study is carried at under varying sample size to assess the performance of this model. Illustration the real dataset indicates that this new distribution can serve as a good alternative model to model positive real data in many areas.

Study and optimization of positioning algorithms for monolithic PET detectors blocks

International Nuclear Information System (INIS)

Acilu, P Garcia de; Sarasola, I; Canadas, M; Cuerdo, R; Mendes, P Rato; Romero, L; Willmott, C

2012-01-01

We are developing a PET insert for existing MRI equipment to be used in clinical PET/MR studies of the human brain. The proposed scanner is based on annihilation gamma detection with monolithic blocks of cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) coupled to magnetically-compatible avalanche photodiodes (APD) matrices. The light distribution generated on the LYSO:Ce block provides the impinging position of the 511 keV photons by means of a positioning algorithm. Several positioning methods, from the simplest Anger Logic to more sophisticate supervised-learning Neural Networks (NN), can be implemented to extract the incidence position of gammas directly from the APD signals. Finally, an optimal method based on a two-step Feed-Forward Neural Network has been selected. It allows us to reach a resolution at detector level of 2 mm, and acquire images of point sources using a first BrainPET prototype consisting of two monolithic blocks working in coincidence. Neural networks provide a straightforward positioning of the acquired data once they have been trained, however the training process is usually time-consuming. In order to obtain an efficient positioning method for the complete scanner it was necessary to find a training procedure that reduces the data acquisition and processing time without introducing a noticeable degradation of the spatial resolution. A grouping process and posterior selection of the training data have been done regarding the similitude of the light distribution of events which have one common incident coordinate (transversal or longitudinal). By doing this, the amount of training data can be reduced to about 5% of the initial number with a degradation of spatial resolution lower than 10%.

Proline: the distribution, frequency, positioning, and common functional roles of proline and polyproline sequences in the human proteome.

Directory of Open Access Journals (Sweden)

Alexander A Morgan

Full Text Available Proline is an anomalous amino acid. Its nitrogen atom is covalently locked within a ring, thus it is the only proteinogenic amino acid with a constrained phi angle. Sequences of three consecutive prolines can fold into polyproline helices, structures that join alpha helices and beta pleats as architectural motifs in protein configuration. Triproline helices are participants in protein-protein signaling interactions. Longer spans of repeat prolines also occur, containing as many as 27 consecutive proline residues. Little is known about the frequency, positioning, and functional significance of these proline sequences. Therefore we have undertaken a systematic bioinformatics study of proline residues in proteins. We analyzed the distribution and frequency of 687,434 proline residues among 18,666 human proteins, identifying single residues, dimers, trimers, and longer repeats. Proline accounts for 6.3% of the 10,882,808 protein amino acids. Of all proline residues, 4.4% are in trimers or longer spans. We detected patterns that influence function based on proline location, spacing, and concentration. We propose a classification based on proline-rich, polyproline-rich, and proline-poor status. Whereas singlet proline residues are often found in proteins that display recurring architectural patterns, trimers or longer proline sequences tend be associated with the absence of repetitive structural motifs. Spans of 6 or more are associated with DNA/RNA processing, actin, and developmental processes. We also suggest a role for proline in Kruppel-type zinc finger protein control of DNA expression, and in the nucleation and translocation of actin by the formin complex.

The Differences across Distributed Leadership Practices by School Position According to the Comprehensive Assessment of Leadership for Learning (CALL)

Science.gov (United States)

Blitz, Mark H.; Modeste, Marsha

2015-01-01

The Comprehensive Assessment of Leadership for Learning (CALL) is a multi-source assessment of distributed instructional leadership. As part of the validation of CALL, researchers examined differences between teacher and leader ratings in assessing distributed leadership practices. The authors utilized a t-test for equality of means for the…

Measurement of the thermal flux distribution in the IEA-R1 reactor

International Nuclear Information System (INIS)

Tangari, C.M.; Moreira, J.M.L.; Jerez, R.

1986-01-01

The knowledge of the neutron flux distribution in research reactors is important because it gives the power distribution over the core, and it provides better conditions to perform experiments and sample irradiations. The measured neutron flux distribution can also be of interest as a means of comparison for the calculational methods of reactor analysis currently in use at this institute. The thermal neutron flux distribution of the IEA-R1 reactor has been measured with the miniature chamber WL-23292. For carrying out the measurements, it was buit a guide system that permit the insertion of the mini-chamber i between the fuel of the fuel elements. It can be introduced in two diferent positions a fuel element and in each it spans 26 axial positions. With this guide system the thermal neutron flux distribution of the IEA-R1 nuclear reactor can be obtained in a fast and efficient manner. The element measured flux distribution shows clearly the effects of control rods and reflectors in the IEA-R1 reactor. The difficulties encountered during the measurements are mentioned with detail as well as the procedures adopteed to overcome them. (Author) [pt

Support force measures of midsized men in seated positions.

Science.gov (United States)

Bush, Tamara Reid; Hubbard, Robert P

2007-02-01

Two areas not well researched in the field of seating mechanics are the distribution of normal and shear forces, and how those forces change with seat position. The availability of these data would be beneficial for the design and development of office, automotive and medical seats. To increase our knowledge in the area of seating mechanics, this study sought to measure the normal and shear loads applied to segmental supports in 12 seated positions, utilizing three inclination angles and four levels of seat back articulation that were associated with automotive driving positions. Force data from six regions, including the thorax, sacral region, buttocks, thighs, feet, and hand support were gathered using multi-axis load cells. The sample contained 23 midsized subjects with an average weight of 76.7 kg and a standard deviation of 4.2 kg, and an average height of 1745 mm with a standard deviation of 19 mm. Results were examined in terms of seat back inclination and in terms of torso articulation for relationships between seat positions and support forces. Using a repeated measures analysis, significant differences (p<0.05) were identified for normal forces relative to all inclination angles except for forces occurring at the hand support. Other significant differences were observed between normal forces behind the buttocks, pelvis, and feet for torso articulations. Significant differences in the shear forces occurred under the buttocks and posterior pelvis during changes in seat back inclination. Significant differences in shear forces were also identified for torso articulations. These data suggest that as seat back inclination or torso articulation change, significant shifts in force distribution occur.

On Selection of the Probability Distribution for Representing the Maximum Annual Wind Speed in East Cairo, Egypt

International Nuclear Information System (INIS)

El-Shanshoury, Gh. I.; El-Hemamy, S.T.

2013-01-01

The main objective of this paper is to identify an appropriate probability model and best plotting position formula which represent the maximum annual wind speed in east Cairo. This model can be used to estimate the extreme wind speed and return period at a particular site as well as to determine the radioactive release distribution in case of accident occurrence at a nuclear power plant. Wind speed probabilities can be estimated by using probability distributions. An accurate determination of probability distribution for maximum wind speed data is very important in expecting the extreme value . The probability plots of the maximum annual wind speed (MAWS) in east Cairo are fitted to six major statistical distributions namely: Gumbel, Weibull, Normal, Log-Normal, Logistic and Log- Logistic distribution, while eight plotting positions of Hosking and Wallis, Hazen, Gringorten, Cunnane, Blom, Filliben, Benard and Weibull are used for determining exceedance of their probabilities. A proper probability distribution for representing the MAWS is selected by the statistical test criteria in frequency analysis. Therefore, the best plotting position formula which can be used to select appropriate probability model representing the MAWS data must be determined. The statistical test criteria which represented in: the probability plot correlation coefficient (PPCC), the root mean square error (RMSE), the relative root mean square error (RRMSE) and the maximum absolute error (MAE) are used to select the appropriate probability position and distribution. The data obtained show that the maximum annual wind speed in east Cairo vary from 44.3 Km/h to 96.1 Km/h within duration of 39 years . Weibull plotting position combined with Normal distribution gave the highest fit, most reliable, accurate predictions and determination of the wind speed in the study area having the highest value of PPCC and lowest values of RMSE, RRMSE and MAE

Genetic diversity, phylogroup distribution and virulence gene profile of pks positive Escherichia coli colonizing human intestinal polyps.

Science.gov (United States)

Sarshar, Meysam; Scribano, Daniela; Marazzato, Massimiliano; Ambrosi, Cecilia; Aprea, Maria Rita; Aleandri, Marta; Pronio, Annamaria; Longhi, Catia; Nicoletti, Mauro; Zagaglia, Carlo; Palamara, Anna Teresa; Conte, Maria Pia

2017-11-01

Some Escherichia coli strains of phylogroup B2 harbor a (pks) pathogenicity island that encodes a polyketide-peptide genotoxin called colibactin. It causes DNA double-strand breaks and megalocytosis in eukaryotic cells and it may contribute to cancer development. Study of bacterial community that colonizes the adenomatous polyp lesion, defined as precancerous lesions, could be helpful to assess if such pathogenic bacteria possess a role in the polyp progression to cancer. In this cross-sectional study, a total of 1500 E. coli isolates were obtained from biopsies of patients presenting adenomatous colon polyps, the normal tissues adjacent to the polyp lesion and patients presenting normal mucosa. pks island frequency, phylogenetic grouping, fingerprint genotyping, and virulence gene features of pks positive (pks + ) E. coli isolates were performed. We found pks + E. coli strongly colonize two patients presenting polypoid lesions and none were identified in patients presenting normal mucosa. Predominant phylogroups among pks + E. coli isolates were B2, followed by D. Clustering based on fragment profiles of composite analysis, typed the pks + isolates into 5 major clusters (I-V) and 17 sub-clusters, demonstrating a high level of genetic diversity among them. The most prevalent virulence genes were fimH and fyuA (100%), followed by vat (92%), hra and papA (69%), ibeA (28%), and hlyA (25%). Our results revealed that pks + E. coli can colonize the precancerous lesions, with a high distribution in both the polyp lesions and in normal tissues adjacent to the lesion. The high differences in fingerprinting patterns obtained indicate that pks + E. coli strains were genetically diverse, possibly allowing them to more easily adapt to environmental variations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Report on the Sixth International Symposium on Isotopomers

Energy Technology Data Exchange (ETDEWEB)

Bao, H. [Louisiana State Univ., Baton Rouge, LA (United States); Farquhar, J. [Univ. of Maryland, College Park, MD (United States); Rumble, D. [Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab.

2016-05-11

The ISI 2012 met in Washington, DC, 18-22 June 2012, bringing together researchers and their students spanning an unusually wide range of disciplines including quantum and physical chemistry, cosmochemistry, atmospheric chemistry, chemical oceanography, biogeochemistry, organic and inorganic geochemistry. The diversity of subject matter was matched geographically with 92 attendees hailing from Canada, China, Finland, France, Germany, India, Israel, Japan, the Netherlands, Russia, Switzerland, Taiwan, the United Kingdom, and the USA. Although diverse, the group was united in its commitment to use the light stable isotopes of H, C, N, O, and S, with their equilibrium, kinetic, and intramolecular fractionations, to understand the material cycles and their dynamics between atmosphere, biosphere, hydrosphere, and lithosphere that make life possible on Earth. A distinct benefit of a small meeting like ISI 2012 is the opportunity for everyone to talk to each other. The historic rooms of the Carnegie Institution of Washington offered a cozy and warm atmosphere for participants in ISI 2012 to talk science and life in a casual, relaxed, and in-depth fashion. Graduate students and postdoctoral researchers were particularly appreciative of being able to spend five days together with old and new colleagues in comfortable quarters. Many commented that they had gained a lot more in building their life-long working relationships with colleagues at this meeting than at larger meetings.

Distributions asymptotically homogeneous along the trajectories determined by one-parameter groups

International Nuclear Information System (INIS)

Drozhzhinov, Yurii N; Zav'yalov, Boris I

2012-01-01

We give a complete description of distributions that are asymptotically homogeneous (including the case of critical index of the asymptotic scale) along the trajectories determined by continuous multiplicative one-parameter transformation groups such that the real parts of all eigenvalues of the infinitesimal matrix are positive. To do this, we introduce and study special spaces of distributions. As an application of our results, we describe distributions that are homogeneous along such groups.

Low energy acetoin ions CH3C(=O)C(H)(OH)CH3.+ decompose to CH3CO. and CH3CHOH+ via a remarkable "hidden rearrangement"

Science.gov (United States)

Suh, Dennis; Burgers, Peter C.; Terlouw, Johan K.

1995-06-01

Tandem mass spectrometry based experiments on D and 18O labelled acetoin isotopomers show that the title reaction is not just a simple bond cleavage, but rather involves rearrangement via ion--dipole complexes; the intermediacy of a charge-transfer complex is proposed to account for the observed product ratios.

The quantification of gluconeogenesis in healthy men by (2)H2O and [2-(13)C]glycerol yields different results: rates of gluconeogenesis in healthy men measured with (2)H2O are higher than those measured with [2-(13)C]glycerol

NARCIS (Netherlands)

Ackermans, M. T.; Pereira Arias, A. M.; Bisschop, P. H.; Endert, E.; Sauerwein, H. P.; Romijn, J. A.

2001-01-01

The quantification of gluconeogenesis (GNG) by (2)H2O and [2-(13)C]glycerol and the mass isotopomer dilution analysis of glucose does not involve assumptions regarding the enrichment of the oxaloacetate precursor pool. To compare these two methods we measured GNG in six healthy postabsorptive males

Process and equipment for monitoring flux distribution in a nuclear reactor outside the core

International Nuclear Information System (INIS)

Graham, K.F.; Gopal, R.

1977-01-01

This concerns the monitoring system for axial flux distribution during the whole load operating range lying outside the core of, for example, a PWR. Flux distribution cards can be produced continuously. The core is divided into at least three sections, which are formed by dividing it at right angles to the longitudinal axis, and the flux is measured outside the core using adjacent detectors. Their output signals are calibrated by amplifiers so that the load distribution in the associated sections is reproduced. A summation of the calibrated output signals and the formation of a mean load signal takes place in summing stages. For monitoring, this is compared with a value which corresponds to the maximum permissible load setting. Apart from this the position of the control rods in the core can be taken into account by multiplication of the mean load signals by suitable peak factors. The distribution of monitoring positions or the position of the detectors can be progressive or symmetrical along the axis. (DG) 891 HP [de

Distribution of N-glycosylation sequons in proteins: how apart are they?

DEFF Research Database (Denmark)

Rao, Shyama Prasad; Buus, Ole Thomsen; Wollenweber, Bernd

2011-01-01

of experimentally confirmed eukaryotic N-glycoproteins we analyzed the relative position and distribution of sequons. N-Glycosylation probability was found to be lower in the termini of protein sequences compared to the mid region. N-glycosylated sequons were found much farther from C terminus compared to the N......N-glycosylation is a common protein modification process, which affects a number of properties of proteins. Little is known about the distribution of N-glycosylation sequons, for example, the distance between glycosylated sites and their position in the protein primary sequence. Using a large set......-terminus of the protein sequence and this effect was more pronounced for NXS sequons. The distribution of sequons, modeled based on balls-in-boxes classical occupancy, showed a near-maximum probability. Considerable proportion of sequons was found within a distance of ten amino acids, indicating that the steric hindrance...

Influence of a Large Pillar on the Optimum Roadway Position in an Extremely Close Coal Seam

Directory of Open Access Journals (Sweden)

Li Yang

2016-01-01

Full Text Available Based on the mining practice in an extremely close coal seam, theoretical analysis was conducted on the vertical stress distribution of the floor strata under a large coal pillar. The vertical stress distribution regulation of a No. 5 coal seam was revealed. To obtain the optimum position of the roadway that bears the supporting pressure of a large coal pillar, numerical modeling was applied to analyze the relation among the stress distribution of the roadway surrounding the rock that bears the supporting pressure of a large coal pillar, the plastic zone distribution of the roadway surrounding the rock, the surrounding rock deformation, and the roadway layout position. The theoretical calculation results of the stress value, stress variation rate, and influencing range of the stress influencing angle showed that the reasonable malposition of the No. 5 coal seam roadway was an inner malposition of 4 m. The mining practice showed the following: the layout of No. 25301 panel belt roadway at the position of the inner malposition of 4 m was reasonable, the roadway support performance was favourable without deformation, and ground pressure was not obvious. The research achievement of this study is the provision of a reference for roadway layouts under similar conditions.

Single-server queues with spatially distributed arrivals

NARCIS (Netherlands)

Kroese, Dirk; Schmidt, Volker

1994-01-01

Consider a queueing system where customers arrive at a circle according to a homogeneous Poisson process. After choosing their positions on the circle, according to a uniform distribution, they wait for a single server who travels on the circle. The server's movement is modelled by a Brownian motion

Optimal dividend distribution under Markov regime switching

NARCIS (Netherlands)

Jiang, Z.; Pistorius, M.

2012-01-01

We investigate the problem of optimal dividend distribution for a company in the presence of regime shifts. We consider a company whose cumulative net revenues evolve as a Brownian motion with positive drift that is modulated by a finite state Markov chain, and model the discount rate as a

Implications of a positive sentinel node in oral squamous cell carcinoma

DEFF Research Database (Denmark)

Gurney, Benjamin A S; Schilling, Clare; Putcha, Venkata

2012-01-01

BACKGROUND: The role of sentinel node biopsy in head and neck cancer is currently being explored. Patients with positive sentinel nodes were investigated to establish if additional metastases were present in the neck, their distribution, and their impact on outcome. METHODS: In all, 109 patients ...

EL-2 reactor: Thermal neutron flux distribution

International Nuclear Information System (INIS)

Rousseau, A.; Genthon, J.P.

1958-01-01

The flux distribution of thermal neutrons in EL-2 reactor is studied. The reactor core and lattices are described as well as the experimental reactor facilities, in particular, the experimental channels and special facilities. The measurement shows that the thermal neutron flux increases in the central channel when enriched uranium is used in place of natural uranium. However the thermal neutron flux is not perturbed in the other reactor channels by the fuel modification. The macroscopic flux distribution is measured according the radial positioning of fuel rods. The longitudinal neutron flux distribution in a fuel rod is also measured and shows no difference between enriched and natural uranium fuel rods. In addition, measurements of the flux distribution have been effectuated for rods containing other material as steel or aluminium. The neutron flux distribution is also studied in all the experimental channels as well as in the thermal column. The determination of the distribution of the thermal neutron flux in all experimental facilities, the thermal column and the fuel channels has been made with a heavy water level of 1825 mm and is given for an operating power of 1000 kW. (M.P.)

Maximum likelihood positioning algorithm for high-resolution PET scanners

International Nuclear Information System (INIS)

Gross-Weege, Nicolas; Schug, David; Hallen, Patrick; Schulz, Volkmar

2016-01-01

Purpose: In high-resolution positron emission tomography (PET), lightsharing elements are incorporated into typical detector stacks to read out scintillator arrays in which one scintillator element (crystal) is smaller than the size of the readout channel. In order to identify the hit crystal by means of the measured light distribution, a positioning algorithm is required. One commonly applied positioning algorithm uses the center of gravity (COG) of the measured light distribution. The COG algorithm is limited in spatial resolution by noise and intercrystal Compton scatter. The purpose of this work is to develop a positioning algorithm which overcomes this limitation. Methods: The authors present a maximum likelihood (ML) algorithm which compares a set of expected light distributions given by probability density functions (PDFs) with the measured light distribution. Instead of modeling the PDFs by using an analytical model, the PDFs of the proposed ML algorithm are generated assuming a single-gamma-interaction model from measured data. The algorithm was evaluated with a hot-rod phantom measurement acquired with the preclinical HYPERION II D PET scanner. In order to assess the performance with respect to sensitivity, energy resolution, and image quality, the ML algorithm was compared to a COG algorithm which calculates the COG from a restricted set of channels. The authors studied the energy resolution of the ML and the COG algorithm regarding incomplete light distributions (missing channel information caused by detector dead time). Furthermore, the authors investigated the effects of using a filter based on the likelihood values on sensitivity, energy resolution, and image quality. Results: A sensitivity gain of up to 19% was demonstrated in comparison to the COG algorithm for the selected operation parameters. Energy resolution and image quality were on a similar level for both algorithms. Additionally, the authors demonstrated that the performance of the ML

Influence of dental occlusion on postural control and plantar pressure distribution.

Science.gov (United States)

Scharnweber, Benjamin; Adjami, Frederic; Schuster, Gabriele; Kopp, Stefan; Natrup, Jörg; Erbe, Christina; Ohlendorf, Daniela

2017-11-01

The number of studies investigating correlations between the temporomandibular system and body posture, postural control or plantar pressure distribution is continuously increasing. If a connection can be found, it is often of minor influence or for only a single parameter. However, small subject groups are critical. This study was conducted to define correlations between dental parameters, postural control and plantar pressure distribution in healthy males. In this study, 87 male subjects with an average age of 25.23 ± 3.5 years (ranging from 18 to 35 years) were examined. Dental casts of the subjects were analyzed. Postural control and plantar pressure distribution were recorded by a force platform. Possible orthodontic and orthopedic factors of influence were determined by either an anamnesis or a questionnaire. All tests performed were randomized and repeated three times each for intercuspal position (ICP) and blocked occlusion (BO). For a statistical analysis of the results, non-parametric tests (Wilcoxon-Matched-Pairs-Test, Kruskall-Wallis-Test) were used. A revision of the results via Bonferroni-Holm correction was considered. ICP increases body sway in the frontal (p ≤ 0.01) and sagittal planes (p ≤ 0.03) compared to BO, whereas all other 29 correlations were independent of the occlusion position. For both of the ICP or BO cases, Angle-class, midline-displacement, crossbite, or orthodontic therapy were found to have no influence on postural control or plantar pressure distribution (p > 0.05). However, the contact time of the left foot decreased (p ≤ 0.001) while detecting the plantar pressure distribution in each position. Persistent dental parameters have no effect on postural sway. In addition, postural control and plantar pressure distribution have been found to be independent postural criteria.

35Cl/37Cl isotope effects in 103Rh NMR of [RhCln(H2O)6−n]3−n complex anions in hydrochloric acid solution as a unique ‘NMR finger-print’ for unambiguous speciation

International Nuclear Information System (INIS)

Geswindt, Theodor E.; Gerber, Wilhelmus J.; Brand, D. Jacobus; Koch, Klaus R.

2012-01-01

Graphical abstract: 35 Cl/ 37 Cl isotope effects in 103 Rh NMR as a unique ‘NMR-fingerprints’ leading to the unambiguous assignment of [RhCl n (H 2 O) 6−n ] 3−n (n = 3–6) complexes without reliance on accurate δ( 103 Rh) chemical shifts. Highlights: ► Direct 103 Rh NMR (19.11 MHz) spectroscopic method of speciation of [RhCl n (H 2 O) 6−n ] 3−n in HCl. ► 35 Cl/ 37 Cl isotope effects in 103 Rh NMR of [RhCl n (H 2 O) 6−n ] 3−n anions isotopologue and isotopomer induced 103 Rh NMR ‘finger-print’ for unambiguous identification. ► 103 Rh NMR identification of stereoisomers without a need for accurate chemical shifts. - Abstract: A detailed analysis of the 35 Cl/ 37 Cl isotope effects observed in the 19.11 MHz 103 Rh NMR resonances of [RhCl n (H 2 O) 6−n ] 3−n complexes (n = 3–6) in acidic solution at 292.1 K, shows that the ‘fine structure’ of each 103 Rh resonance can be understood in terms of the unique isotopologue and in certain instances the isotopomer distribution in each complex. These 35 Cl/ 37 Cl isotope effects in the 103 Rh NMR resonance of the [Rh 35/37 Cl 6 ] 3− species manifest only as a result of the statistically expected 35 Cl/ 37 Cl isotopologues, whereas for the aquated species such as for example [Rh 35/37 Cl 5 (H 2 O)] 2− , cis-[Rh 35/37 Cl 4 (H 2 O) 2 ] − as well as the mer-[Rh 35/37 Cl 3 (H 2 O) 3 ] complexes, additional fine-structure due to the various possible isotopomers within each class of isotopologues, is visible. Of interest is the possibility of the direct identification of stereoisomers cis-[RhCl 4 (H 2 O) 2 ] − , trans-[RhCl 4 (H 2 O) 2 ] − , fac-[RhCl 3 (H 2 O) 3 ] and mer-[RhCl 3 (H 2 O) 3 ] based on the 103 Rh NMR line shape, other than on the basis of their very similar δ( 103 Rh) chemical shift. The 103 Rh NMR resonance structure thus serves as a novel and unique ‘NMR-fingerprint’ leading to the unambiguous assignment of [RhCl n (H 2 O) 6−n ] 3−n complexes (n = 3–6

Distributed predictive control of spiral wave in cardiac excitable media

International Nuclear Information System (INIS)

Zheng-Ning, Gan; Xin-Ming, Cheng

2010-01-01

In this paper, we propose the distributed predictive control strategies of spiral wave in cardiac excitable media. The modified FitzHugh–Nagumo model was used to express the cardiac excitable media approximately. Based on the control-Lyapunov theory, we obtained the distributed control equation, which consists of a positive control-Lyapunov function and a positive cost function. Using the equation, we investigate two kinds of robust control strategies: the time-dependent distributed control strategy and the space-time dependent distributed control strategy. The feasibility of the strategies was demonstrated via an illustrative example, in which the spiral wave was prevented to occur, and the possibility for inducing ventricular fibrillation was eliminated. The strategies are helpful in designing various cardiac devices. Since the second strategy is more efficient and robust than the first one, and the response time in the second strategy is far less than that in the first one, the former is suitable for the quick-response control systems. In addition, our spatiotemporal control strategies, especially the second strategy, can be applied to other cardiac models, even to other reaction-diffusion systems. (general)

Influence of random setup error on dose distribution

International Nuclear Information System (INIS)

Zhai Zhenyu

2008-01-01

Objective: To investigate the influence of random setup error on dose distribution in radiotherapy and determine the margin from ITV to PTV. Methods: A random sample approach was used to simulate the fields position in target coordinate system. Cumulative effect of random setup error was the sum of dose distributions of all individual treatment fractions. Study of 100 cumulative effects might get shift sizes of 90% dose point position. Margins from ITV to PTV caused by random setup error were chosen by 95% probability. Spearman's correlation was used to analyze the influence of each factor. Results: The average shift sizes of 90% dose point position was 0.62, 1.84, 3.13, 4.78, 6.34 and 8.03 mm if random setup error was 1,2,3,4,5 and 6 mm,respectively. Univariate analysis showed the size of margin was associated only by the size of random setup error. Conclusions: Margin of ITV to PTV is 1.2 times random setup error for head-and-neck cancer and 1.5 times for thoracic and abdominal cancer. Field size, energy and target depth, unlike random setup error, have no relation with the size of the margin. (authors)

Quantitative risk stratification in Markov chains with limiting conditional distributions.

Science.gov (United States)

Chan, David C; Pollett, Philip K; Weinstein, Milton C

2009-01-01

Many clinical decisions require patient risk stratification. The authors introduce the concept of limiting conditional distributions, which describe the equilibrium proportion of surviving patients occupying each disease state in a Markov chain with death. Such distributions can quantitatively describe risk stratification. The authors first establish conditions for the existence of a positive limiting conditional distribution in a general Markov chain and describe a framework for risk stratification using the limiting conditional distribution. They then apply their framework to a clinical example of a treatment indicated for high-risk patients, first to infer the risk of patients selected for treatment in clinical trials and then to predict the outcomes of expanding treatment to other populations of risk. For the general chain, a positive limiting conditional distribution exists only if patients in the earliest state have the lowest combined risk of progression or death. The authors show that in their general framework, outcomes and population risk are interchangeable. For the clinical example, they estimate that previous clinical trials have selected the upper quintile of patient risk for this treatment, but they also show that expanded treatment would weakly dominate this degree of targeted treatment, and universal treatment may be cost-effective. Limiting conditional distributions exist in most Markov models of progressive diseases and are well suited to represent risk stratification quantitatively. This framework can characterize patient risk in clinical trials and predict outcomes for other populations of risk.

Mapping the geographical distribution of lymphatic filariasis in Zambia

DEFF Research Database (Denmark)

Mwase, Enala T; Stensgaard, Anna-Sofie; Nsakashalo-Senkwe, Mutale

2014-01-01

to be an important determinant of medium-high prevalence levels. CONCLUSIONS/SIGNIFICANCE: LF was found to be surprisingly widespread in Zambia, although in most places with low prevalence. The produced maps and the identified environmental correlates of LF infection will provide useful guidance for planning...... volunteers from 108 geo-referenced survey sites across Zambia were examined for circulating filarial antigens (CFA) with rapid format ICT cards, and a map indicating the distribution of CFA prevalences in Zambia was prepared. 78% of survey sites had CFA positive cases, with prevalences ranging between 1......% and 54%. Most positive survey sites had low prevalence, but six foci with more than 15% prevalence were identified. The observed geographical variation in prevalence pattern was examined in more detail using a species distribution modeling approach to explore environmental requirements for parasite...

Sampling theorem for geometric moment determination and its application to a laser beam position detector.

Science.gov (United States)

Loce, R P; Jodoin, R E

1990-09-10

Using the tools of Fourier analysis, a sampling requirement is derived that assures that sufficient information is contained within the samples of a distribution to calculate accurately geometric moments of that distribution. The derivation follows the standard textbook derivation of the Whittaker-Shannon sampling theorem, which is used for reconstruction, but further insight leads to a coarser minimum sampling interval for moment determination. The need for fewer samples to determine moments agrees with intuition since less information should be required to determine a characteristic of a distribution compared with that required to construct the distribution. A formula for calculation of the moments from these samples is also derived. A numerical analysis is performed to quantify the accuracy of the calculated first moment for practical nonideal sampling conditions. The theory is applied to a high speed laser beam position detector, which uses the normalized first moment to measure raster line positional accuracy in a laser printer. The effects of the laser irradiance profile, sampling aperture, number of samples acquired, quantization, and noise are taken into account.

Regulative feedback in pattern formation: towards a general relativistic theory of positional information.

Science.gov (United States)

Jaeger, Johannes; Irons, David; Monk, Nick

2008-10-01

Positional specification by morphogen gradients is traditionally viewed as a two-step process. A gradient is formed and then interpreted, providing a spatial metric independent of the target tissue, similar to the concept of space in classical mechanics. However, the formation and interpretation of gradients are coupled, dynamic processes. We introduce a conceptual framework for positional specification in which cellular activity feeds back on positional information encoded by gradients, analogous to the feedback between mass-energy distribution and the geometry of space-time in Einstein's general theory of relativity. We discuss how such general relativistic positional information (GRPI) can guide systems-level approaches to pattern formation.

On the production of positive molecular ions in cometary comas

International Nuclear Information System (INIS)

Tarafdar, S.P.; Wickramasinghe, N.C.

1977-01-01

Positively charged molecular ions, such as H 2 O + , which have been observed in cometary comas, may be efficiently produced by the evaporation of positively charged clathrate grains of radii in the range approximately 10 -6 -10 -3 cm. Such grains may be expelled from nuclei of comets, along with gaseous molecules. Grain charging occurs via interaction with solar ultraviolet photons and/or solar wind protons. Observational data on the total quantities as well as the distributions of H 2 O and H 2 O + in cometary comas are shown to be in accord with detailed model calculations. (Auth.)

Effect of organ size and position on out-of-field dose distributions during radiation therapy

International Nuclear Information System (INIS)

Scarboro, Sarah B; White, Allen; Yaldo, Derek; Kry, Stephen F; Howell, Rebecca M; Stovall, Marilyn; Smith, Susan A

2010-01-01

Mantle field irradiation has historically been the standard radiation treatment for Hodgkin lymphoma. It involves treating large regions of the chest and neck with high doses of radiation (up to 30 Gy). Previous epidemiological studies on the incidence of second malignancies following radiation therapy for Hodgkin lymphoma have revealed an increased incidence of second tumors in various organs, including lung, breast, thyroid and digestive tract. Multiple other studies, including the Surveillance, Epidemiology and End Results, indicated an increased incidence in digestive tract including stomach cancers following mantle field radiotherapy. Assessment of stomach dose is challenging because the stomach is outside the treatment field but very near the treatment border where there are steep dose gradients. In addition, the stomach can vary greatly in size and position. We sought to evaluate the dosimetric impact of the size and variable position of the stomach relative to the field border for a typical Hodgkin lymphoma mantle field irradiation. The mean stomach dose was measured using thermoluminescent dosimetry for nine variations in stomach size and position. The mean doses to the nine stomach variations ranged from 0.43 to 0.83 Gy when 30 Gy was delivered to the treatment isocenter. Statistical analyses indicated that there were no significant differences in the mean stomach dose when the stomach was symmetrically expanded up to 3 cm or shifted laterally (medial, anterior or posterior shifts) by up to 3 cm. There was, however, a significant (P > 0.01) difference in the mean dose when the stomach was shifted superiorly or inferiorly by ≥2.5 cm.

Parton distributions from SMC and SLAC data

International Nuclear Information System (INIS)

Ramsey, G.P.

1996-01-01

We have extracted spin-weighted parton distributions in a proton from recent data at CERN and SLAC. The valence, sea quark and Antiquark spin-weighted distributions are determined separately. The data are all consistent with a small to moderate polarized gluon distribution, so that the anomaly term is not significant in the determination of the constituent contributions to the spin of the proton. We have analyzed the consistency of the results obtained from various sets of data and the Biorken sum rule. Although all data are consistent with the sum rule, the polarized distributions from different experiments vary, even with higher order QCD corrections taken into account. Results split into two models, one set implying a large polarized strange sea which violates the positivity bound, and the other set yielding a smaller polarized strange sea. Only further experiments which extract information about the polarized sea will reconcile these differences. We suggest specific experiments which can be performed to determine the size of the polarized sea and gluons

Properties of the center of gravity as an algorithm for position measurements: Two-dimensional geometry

CERN Document Server

Landi, Gregorio

2003-01-01

The center of gravity as an algorithm for position measurements is analyzed for a two-dimensional geometry. Several mathematical consequences of discretization for various types of detector arrays are extracted. Arrays with rectangular, hexagonal, and triangular detectors are analytically studied, and tools are given to simulate their discretization properties. Special signal distributions free of discretized error are isolated. It is proved that some crosstalk spreads are able to eliminate the center of gravity discretization error for any signal distribution. Simulations, adapted to the CMS em-calorimeter and to a triangular detector array, are provided for energy and position reconstruction algorithms with a finite number of detectors.

Synthesis and distribution of L-glutamic acid with three different labels

International Nuclear Information System (INIS)

Cohen, M.B.; Spolter, Leonard; Chia Chin Chang; MacDonald, N.S.

1982-01-01

A study was performed to compare the distribution of C-11 L-glutamic acid, labeled on the carboxyl group of either the alpha or gamma carbon with that of N-13 L-glutamic acid in order to determine if the position of the label is of importance in the study of the distribution of glutamic acid

Product of Ginibre matrices: Fuss-Catalan and Raney distributions

Science.gov (United States)

Penson, Karol A.; Życzkowski, Karol

2011-06-01

Squared singular values of a product of s square random Ginibre matrices are asymptotically characterized by probability distributions Ps(x), such that their moments are equal to the Fuss-Catalan numbers of order s. We find a representation of the Fuss-Catalan distributions Ps(x) in terms of a combination of s hypergeometric functions of the type sFs-1. The explicit formula derived here is exact for an arbitrary positive integer s, and for s=1 it reduces to the Marchenko-Pastur distribution. Using similar techniques, involving the Mellin transform and the Meijer G function, we find exact expressions for the Raney probability distributions, the moments of which are given by a two-parameter generalization of the Fuss-Catalan numbers. These distributions can also be considered as a two-parameter generalization of the Wigner semicircle law.

Coordinated Volt/Var Control in Distribution Systems with Distributed Generations Based on Joint Active and Reactive Powers Dispatch

Directory of Open Access Journals (Sweden)

Abouzar Samimi

2016-01-01

Full Text Available One of the most significant control schemes in optimal operation of distribution networks is Volt/Var control (VVC. Owing to the radial structure of distribution systems and distribution lines with a small X/R ratio, the active power scheduling affects the VVC issue. A Distribution System Operator (DSO procures its active and reactive power requirements from Distributed Generations (DGs along with the wholesale electricity market. This paper proposes a new operational scheduling method based on a joint day-ahead active/reactive power market at the distribution level. To this end, based on the capability curve, a generic reactive power cost model for DGs is developed. The joint active/reactive power dispatch model presented in this paper motivates DGs to actively participate not only in the energy markets, but also in the VVC scheme through a competitive market. The proposed method which will be performed in an offline manner aims to optimally determine (i the scheduled active and reactive power values of generation units; (ii reactive power values of switched capacitor banks; and (iii tap positions of transformers for the next day. The joint active/reactive power dispatch model for daily VVC is modeled in GAMS and solved with the DICOPT solver. Finally, the plausibility of the proposed scheduling framework is examined on a typical 22-bus distribution test network over a 24-h period.

Simulating quantum correlations as a distributed sampling problem

International Nuclear Information System (INIS)

Degorre, Julien; Laplante, Sophie; Roland, Jeremie

2005-01-01

It is known that quantum correlations exhibited by a maximally entangled qubit pair can be simulated with the help of shared randomness, supplemented with additional resources, such as communication, postselection or nonlocal boxes. For instance, in the case of projective measurements, it is possible to solve this problem with protocols using one bit of communication or making one use of a nonlocal box. We show that this problem reduces to a distributed sampling problem. We give a new method to obtain samples from a biased distribution, starting with shared random variables following a uniform distribution, and use it to build distributed sampling protocols. This approach allows us to derive, in a simpler and unified way, many existing protocols for projective measurements, and extend them to positive operator value measurements. Moreover, this approach naturally leads to a local hidden variable model for Werner states

Derivation of the point spread function for zero-crossing-demodulated position-sensitive detectors

International Nuclear Information System (INIS)

Nowlin, C.H.

1976-07-01

This work is a mathematical derivation of a high-quality approximation to the point spread function for position-sensitive detectors (PSDs) that use pulse-shape modulation and crossover-time demodulation. The approximation is determined as a general function of the input signals to the crossover detectors so as to enable later determination of optimum position-decoding filters for PSDs. This work is precisely applicable to PSDs that use either RC or LC transmission line encoders. The effects of random variables, such as charge collection time, in the encoding process are included. In addition, this work presents a new, rigorous method for the determination of upper and lower bounds for conditional crossover-time distribution functions (closely related to first-passage-time distribution functions) for arbitrary signals and arbitrary noise covariance functions

Conformational distributions and proximity relationships in the rigor complex of actin and myosin subfragment-1.

Science.gov (United States)

Nyitrai, M; Hild, G; Lukács, A; Bódis, E; Somogyi, B

2000-01-28

Cyclic conformational changes in the myosin head are considered essential for muscle contraction. We hereby show that the extension of the fluorescence resonance energy transfer method described originally by Taylor et al. (Taylor, D. L., Reidler, J., Spudich, J. A., and Stryer, L. (1981) J. Cell Biol. 89, 362-367) allows determination of the position of a labeled point outside the actin filament in supramolecular complexes and also characterization of the conformational heterogeneity of an actin-binding protein while considering donor-acceptor distance distributions. Using this method we analyzed proximity relationships between two labeled points of S1 and the actin filament in the acto-S1 rigor complex. The donor (N-[[(iodoacetyl)amino]ethyl]-5-naphthylamine-1-sulfonate) was attached to either the catalytic domain (Cys-707) or the essential light chain (Cys-177) of S1, whereas the acceptor (5-(iodoacetamido)fluorescein) was attached to the actin filament (Cys-374). In contrast to the narrow positional distribution (assumed as being Gaussian) of Cys-707 (5 +/- 3 A), the positional distribution of Cys-177 was found to be broad (102 +/- 4 A). Such a broad positional distribution of the label on the essential light chain of S1 may be important in accommodating the helically arranged acto-myosin binding relative to the filament axis.

Challenges Women Face in Leadership Positions and Organizational Effectiveness: An Investigation

Science.gov (United States)

Elmuti, Dean; Jia, Heather; Davis, Henry H.

2009-01-01

This study was undertaken to discover working public thoughts about roles of United States women in leadership positions and to test the relationship between managerial leadership styles and organizational effectiveness. A survey of perceptions of leadership roles and effectiveness distributed 700 randomly selected entities from industries in the…

Application of high-brightness LEDs in aircraft position lights

Science.gov (United States)

Machi, Nicolo; Mangum, Scott; Singer, Jeffrey M.

2004-10-01

Solid state lighting devices have made their way into a number of niche markets and continue to make inroads into other markets as their price / performance ratios improve. One of these markets is aviation lighting. Although this paper will focus on the use of LEDs for aircraft position lights, much of the discussion is applicable to other installations on the interior and exterior of the aircraft. The color, light distribution and intensity levels for a position light are all closely regulated through Code of Federal Regulation (CFR; formerly Federal Aviation Regulation (FAR)) documents. These lighting requirements, along with harsh thermal and environmental requirements, drive the design. In this paper, we will look at these requirements and discuss what is required in order to use LEDs for this type of application. We will explore the optical, thermal and electrical issues associated with the use of LEDs for position lights and examine the specific case study of the Astreon forward position lights. Finally, we will discuss some of the challenges that we see with solid state lighting in current and future aircraft applications.

Protocol development for continuous nitrogen-15 measurement of N2O and its isotopomers for real-time greenhouse gas tracing

International Nuclear Information System (INIS)

Slaets, J.; Mayr, L.; Heiling, M.; Zaman, M.; Resch, C.; Weltin, G.; Gruber, R.; Dercon, G.

2016-01-01

Quantifying sources of nitrous oxide (N2O) (soil-N and applied N) is essential to improve our understanding of the global N cycle and to develop climate-smart agriculture, as N 2 O has a global warming potential that is 300 times higher than that of CO 2 . The isotopic signature and the intramolecular distribution (site preference) of 15 N are powerful tools to identify N 2 O sources. We have developed a protocol for continuous (closedloop), real time measurement of the N 2 O flux, the isotopic signature and the intramolecular distribution of 15 N by using off-axis integrated cavity output spectroscopy (ICOS, Los Gatos Research). The method was applied in a fertilizer inhibitor experiment, in which N 2 O emissions were measured on undisturbed soil cores for three weeks. The treatments consisted of enriched 15 N labelled urea (5 atom %) applied at a rate equivalent to 100 kg N/ha), 15 N labelled urea with the nitrification inhibitor (NI) nitrapyrin (375 g/100 kg urea), and controls (no fertilizer or NI).

Looking for capacities rather than vulnerabilities: The moderating effect of health assets on the associations between adverse social position and health.

Science.gov (United States)

Roy, Mathieu; Levasseur, Mélanie; Doré, Isabelle; St-Hilaire, France; Michallet, Bernard; Couturier, Yves; Maltais, Danielle; Lindström, Bengt; Généreux, Mélissa

2018-05-01

To increase capacities and control over health, it is necessary to foster assets (i.e. factors enhancing abilities of individuals or communities). Acting as a buffer, assets build foundations for overcoming adverse conditions and improving health. However, little is known about the distribution of assets and their associations with social position and health. In this study, we documented the distribution of health assets and examined whether these assets moderate associations between adverse social position and self-reported health. A representative population-based cross-sectional survey of adults in the Eastern Townships, Quebec, Canada (n = 8737) was conducted in 2014. Measures included assets (i.e. resilience, sense of community belonging, positive mental health, social participation), self-reported health (i.e. perceived health, psychological distress), and indicators of social position. Distribution of assets was studied in relation to gender and social position. Logistic regressions examined whether each asset moderated associations between adverse social position and self-reported health. Different distributions of assets were observed with different social positions. Women were more likely to participate in social activities while men were more resilient. Resilience and social participation were moderators of associations between adverse social position (i.e. living alone, lower household income) and self-reported health. Having assets contributes to better health by increasing capacities. Interventions that foster assets and complement current public health services are needed, especially for people in unfavorable situations. Health and social services decision-makers and practitioners could use these findings to increase capacities and resources rather than focusing primarily on preventing diseases and reducing risk factors. Copyright © 2018 Elsevier Inc. All rights reserved.

High-precision position estimation in PET using artificial neural networks

Energy Technology Data Exchange (ETDEWEB)

Mateo, F. [Digital Systems Design Group (DSD), Instituto de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas (ITACA), Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)], E-mail: fermaji@upvnet.upv.es; Aliaga, R.J.; Ferrando, N.; Martinez, J.D.; Herrero, V.; Lerche, Ch.W.; Colom, R.J.; Monzo, J.M.; Sebastia, A.; Gadea, R. [Digital Systems Design Group (DSD), Instituto de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas (ITACA), Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

2009-06-01

Traditionally, the most popular technique to predict the impact position of gamma photons on a PET detector has been Anger's logic. However, it introduces nonlinearities that compress the light distribution, reducing the useful field of view and the spatial resolution, especially at the edges of the scintillator crystal. In this work, we make use of neural networks to address a bias-corrected position estimation from real stimulus obtained from a 2D PET system setup. The preprocessing and data acquisition were performed by separate custom boards, especially designed for this application. The results show that neural networks yield a more uniform field of view while improving the systematic error and the spatial resolution. Therefore, they stand as a better performing and readily available alternative to classic positioning methods.

High-precision position estimation in PET using artificial neural networks

International Nuclear Information System (INIS)

Mateo, F.; Aliaga, R.J.; Ferrando, N.; Martinez, J.D.; Herrero, V.; Lerche, Ch.W.; Colom, R.J.; Monzo, J.M.; Sebastia, A.; Gadea, R.

2009-01-01

Traditionally, the most popular technique to predict the impact position of gamma photons on a PET detector has been Anger's logic. However, it introduces nonlinearities that compress the light distribution, reducing the useful field of view and the spatial resolution, especially at the edges of the scintillator crystal. In this work, we make use of neural networks to address a bias-corrected position estimation from real stimulus obtained from a 2D PET system setup. The preprocessing and data acquisition were performed by separate custom boards, especially designed for this application. The results show that neural networks yield a more uniform field of view while improving the systematic error and the spatial resolution. Therefore, they stand as a better performing and readily available alternative to classic positioning methods.

Fundamental limits to position determination by concentration gradients.

Directory of Open Access Journals (Sweden)

Filipe Tostevin

2007-04-01

Full Text Available Position determination in biological systems is often achieved through protein concentration gradients. Measuring the local concentration of such a protein with a spatially varying distribution allows the measurement of position within the system. For these systems to work effectively, position determination must be robust to noise. Here, we calculate fundamental limits to the precision of position determination by concentration gradients due to unavoidable biochemical noise perturbing the gradients. We focus on gradient proteins with first-order reaction kinetics. Systems of this type have been experimentally characterised in both developmental and cell biology settings. For a single gradient we show that, through time-averaging, great precision potentially can be achieved even with very low protein copy numbers. As a second example, we investigate the ability of a system with oppositely directed gradients to find its centre. With this mechanism, positional precision close to the centre improves more slowly with increasing averaging time, and so longer averaging times or higher copy numbers are required for high precision. For both single and double gradients, we demonstrate the existence of optimal length scales for the gradients for which precision is maximized, as well as analyze how precision depends on the size of the concentration-measuring apparatus. These results provide fundamental constraints on the positional precision supplied by concentration gradients in various contexts, including both in developmental biology and also within a single cell.

Distribution of Depositors’ Return and The Income Smoothing Hypothesis by Malaysian Islamic Banks

Directory of Open Access Journals (Sweden)

Zunaidah Sulong

2018-01-01

Full Text Available The paper aims to examine whether Malaysian Islamic banks carry out income smoothing with regards to their distribution of depositors’ return. The paper also examines the extent Malaysian Islamic banks engage earnings and capital management in their distribution of depositors’ return. This empirical study uses balanced panel data from 16 Malaysian Islamic banks, for the period 2008-2012. The regression model is estimated using random effects specifications. The findings indicate that the earnings before tax, zakat, and provision have a positive but insignificant effect on distribution of depositors’ return (DDR whilst the total capital before provision has a positive and significant effect on the DDR. These findings suggest that Islamic banks carry out income smoothing on the distribution of depositors’ return via capital management. Islamic banks also smooth their earnings through distribution of depositors’ return to avoid earnings troughs when earnings are poor. The findings shows prudence exercise among Malaysian Islamic banks with the objectives of mitigating displaced commercial risk (DCR, which involves massive withdrawal and bank runs risks.

Distributions of alkali metals, alkaline earth metals and halogens in cabbage leaves

International Nuclear Information System (INIS)

Tsukada, Hirofumi; Takeda, Akira; Hasegawa, Hidenao

2007-01-01

The distributions of stable elements in plant components provide useful information for understanding the behavior of radionuclides in plants. An entire cabbage plant sample was collected from an experimental field, and the distributions of alkali metals (K, Rb and Cs), alkaline earth metals (Ca, Sr and Ba) and halogens (Cl and I) were determined for cabbage leaves at different positions. The concentration of Cs in outer (older) cabbage leaves was higher than that in inner (younger) leaves, but the distributions of K and Rb concentrations were relatively similar in cabbage leaves, independent of leaf positions. The concentration of Sr in older cabbage leaves was one order of magnitude higher than that in younger leaves. The distributions of Ca, Ba and Sr concentrations in the plant followed a similar pattern. The concentrations of halogens were also very rich in the outer leaves. The percentage distributions of Cs, Sr, Cl and I in the inedible (extreme outer) leaves were 77, 91, 93 and 96% of the total content in the leaf part, respectively. These results show that the inedible plant components are important for understanding the transfer of the radioactive Cs, Sr Cl and I in soil-plant systems. (author)

Local Geoid Determination Using the Global Positioning System

Science.gov (United States)

1988-09-01

Positioning System by Ma, Wei-Ming September 1988 Co-Advisor: Kandiah Jeyapalan Co-Advisor: Stevens P. Tucker Approved for public release; distribution is... Jeyapalan and Stevens P. Tucker, my thesis advisors, for their dedicated assistance and guidance during the study. Without their encouragement...method of collocation is [ Jeyapalan , 1977]: x = A*X+S +n +O.S q q P where x the vector of the observation (x = Ah - N0(X,Y,Z) - H) A a given rectangular

Explaining the inefficiency of electrical distribution companies. Peruvian firms

Energy Technology Data Exchange (ETDEWEB)

Perez-Reyes, Raul [Organismo Supervisor de la Inversion en Energia y Mineria, OSINERGMIN (Peru); Tovar, Beatriz [Infrastructure and Transport Research Group (EIT), Department of Applied Economics, University of Palmas de Gran Canaria (Spain)

2010-09-15

This paper investigates the extent to which the structural reform of the Peruvian electricity market, implemented in the 1990s, has improved the efficiency of the distribution companies; and it evaluates the influence on efficiency of firm specific explanatory variables. To do this, we rely on data from 14 distribution companies between 1996 and 2006. The results indicate that the incentives generated by the reform process led to the firms becoming more efficient. Moreover, the time trend and private management of the distribution companies are variables that positively affect the levels of efficiency, whereas the lower network densities are then the greater the inefficiency. (author)

Explaining the inefficiency of electrical distribution companies. Peruvian firms

International Nuclear Information System (INIS)

Perez-Reyes, Raul; Tovar, Beatriz

2010-01-01

This paper investigates the extent to which the structural reform of the Peruvian electricity market, implemented in the 1990s, has improved the efficiency of the distribution companies; and it evaluates the influence on efficiency of firm specific explanatory variables. To do this, we rely on data from 14 distribution companies between 1996 and 2006. The results indicate that the incentives generated by the reform process led to the firms becoming more efficient. Moreover, the time trend and private management of the distribution companies are variables that positively affect the levels of efficiency, whereas the lower network densities are then the greater the inefficiency. (author)

Helicity-dependent generalized parton distributions for nonzero skewness

Energy Technology Data Exchange (ETDEWEB)

Mondal, Chandan [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China)

2017-09-15

We investigate the helicity-dependent generalized parton distributions (GPDs) in momentum as well as transverse position (impact) spaces for the u and d quarks in a proton when the momentum transfer in both the transverse and the longitudinal directions are nonzero. The GPDs are evaluated using the light-front wave functions of a quark-diquark model for nucleon where the wave functions are constructed by the soft-wall AdS/QCD correspondence. We also express the GPDs in the boost-invariant longitudinal position space. (orig.)

Positive selection on the killer whale mitogenome

DEFF Research Database (Denmark)

Foote, Andrew David; Morin, Phillip A.; Durban, John W.

2011-01-01

Mitochondria produce up to 95 per cent of the eukaryotic cell's energy. The coding genes of the mitochondrial DNA may therefore evolve under selection owing to metabolic requirements. The killer whale, Orcinus orca, is polymorphic, has a global distribution and occupies a range of ecological niches....... It is therefore a suitable organism for testing this hypothesis. We compared a global dataset of the complete mitochondrial genomes of 139 individuals for amino acid changes that were associated with radical physico-chemical property changes and were influenced by positive selection. Two such selected non...

Rank Regressions, Wage Distributions, and the Gender Gap.

Science.gov (United States)

Fortin, Nicole M.; Lemieux, Thomas

1998-01-01

Current Population Survey data from 1979 and 1991 were used to decompose changes in the gender wage gap into three components: skill distribution, wage structure, and improvements in women's position. Relative wage gains by women may have been a source of increasing wage inequality among men. (SK)

The synthesis of (-)-4-methyl-8-chloro-trans-1,2,3,4,4a,5,6,10b-octahydrobenzo-[f]-quinolin-3-one-[3-14C] (LY300502-[14C]) via a circuitous route

International Nuclear Information System (INIS)

Fengjiun Kuo; Wheeler, W.J.

1994-01-01

The synthesis of the C-14 labeled isotopomer of LY300502, a potent 5α-reductase inhibitor has been accomplished in four radiochemical steps. The route involves the synthesis of LY300502-[ 14 C] from LY300502 via a circuitous route; the label was introduced with ethyl chloroformate-[carbonyl- 14 C]. (author)

Consonant acquisition: a first approach to the distribution of errors in four positions in the word

Directory of Open Access Journals (Sweden)

Silvia Llach

2012-12-01

Full Text Available The goal of this study is to describe the behavior of errors in two types of onsets (initial and intervocalic and two types of codas (in the middle and end of the word in order to determine if any of these positions are more prone to specific types of errors than the others.We have looked into the errors that are frequently produced in these four contexts during the acquisition of consonant sounds in the Catalan language. The data were taken from a study on the acquisition of consonants in Catalan, carried out on 90 children between the ages of 3 and 5 years from several kindergarten schools. The results do show that there are characteristic errors depending on the position within the word.

Depth of interaction detection with enhanced position-sensitive proportional resistor network

International Nuclear Information System (INIS)

Lerche, Ch.W.; Benlloch, J.M.; Sanchez, F.; Pavon, N.; Gimenez, N.; Fernandez, M.; Gimenez, M.; Sebastia, A.; Martinez, J.; Mora, F.J.

2005-01-01

A new method of determining the depth of interaction of γ-rays in thick inorganic scintillation crystals was tested experimentally. The method uses the strong correlation between the width of the scintillation light distribution within large continuous crystals and the γ-ray's interaction depth. This behavior was successfully reproduced by a theoretical model distribution based on the inverse square law. For the determination of the distribution's width, its standard deviation σ is computed using an enhanced position-sensitive proportional resistor network which is often used in γ-ray-imaging devices. Minor changes of this known resistor network allow the analog and real-time determination of the light distribution's 2nd moment without impairing the measurement of the energy and centroid. First experimental results are presented that confirm that the described method works correctly. Since only some cheap electronic components, but no additional detectors or crystals are required, the main advantage of this method is its low cost

Cluster-Randomized, Crossover Trial of Head Positioning in Acute Stroke.

Science.gov (United States)

Anderson, Craig S; Arima, Hisatomi; Lavados, Pablo; Billot, Laurent; Hackett, Maree L; Olavarría, Verónica V; Muñoz Venturelli, Paula; Brunser, Alejandro; Peng, Bin; Cui, Liying; Song, Lily; Rogers, Kris; Middleton, Sandy; Lim, Joyce Y; Forshaw, Denise; Lightbody, C Elizabeth; Woodward, Mark; Pontes-Neto, Octavio; De Silva, H Asita; Lin, Ruey-Tay; Lee, Tsong-Hai; Pandian, Jeyaraj D; Mead, Gillian E; Robinson, Thompson; Watkins, Caroline

2017-06-22

The role of supine positioning after acute stroke in improving cerebral blood flow and the countervailing risk of aspiration pneumonia have led to variation in head positioning in clinical practice. We wanted to determine whether outcomes in patients with acute ischemic stroke could be improved by positioning the patient to be lying flat (i.e., fully supine with the back horizontal and the face upwards) during treatment to increase cerebral perfusion. In a pragmatic, cluster-randomized, crossover trial conducted in nine countries, we assigned 11,093 patients with acute stroke (85% of the strokes were ischemic) to receive care in either a lying-flat position or a sitting-up position with the head elevated to at least 30 degrees, according to the randomization assignment of the hospital to which they were admitted; the designated position was initiated soon after hospital admission and was maintained for 24 hours. The primary outcome was degree of disability at 90 days, as assessed with the use of the modified Rankin scale (scores range from 0 to 6, with higher scores indicating greater disability and a score of 6 indicating death). The median interval between the onset of stroke symptoms and the initiation of the assigned position was 14 hours (interquartile range, 5 to 35). Patients in the lying-flat group were less likely than patients in the sitting-up group to maintain the position for 24 hours (87% vs. 95%, P<0.001). In a proportional-odds model, there was no significant shift in the distribution of 90-day disability outcomes on the global modified Rankin scale between patients in the lying-flat group and patients in the sitting-up group (unadjusted odds ratio for a difference in the distribution of scores on the modified Rankin scale in the lying-flat group, 1.01; 95% confidence interval, 0.92 to 1.10; P=0.84). Mortality within 90 days was 7.3% among the patients in the lying-flat group and 7.4% among the patients in the sitting-up group (P=0.83). There were

Feynman quasi probability distribution for spin-(1/2), and its generalizations

International Nuclear Information System (INIS)

Colucci, M.

1999-01-01

It has been examined the Feynman's paper Negative probability, in which, after a discussion about the possibility of attributing a real physical meaning to quasi probability distributions, he introduces a new kind of distribution for spin-(1/2), with a possible method of generalization to systems with arbitrary number of states. The principal aim of this article is to shed light upon the method of construction of these distributions, taking into consideration their application to some experiments, and discussing their positive and negative aspects

Interfraction and intrafraction performance of the Gamma Knife Extend system for patient positioning and immobilization.

Science.gov (United States)

Schlesinger, David; Xu, Zhiyuan; Taylor, Frances; Yen, Chun-Po; Sheehan, Jason

2012-12-01

The Extend system for the Gamma Knife Perfexion makes possible multifractional Gamma Knife treatments. The Extend system consists of a vacuum-monitored immobilization frame and a positioning measurement system used to determine the location of the patient's head within the frame at the time of simulation imaging and before each treatment fraction. The measurement system consists of a repositioning check tool (RCT), which attaches to the Extend frame, and associated digital measuring gauges. The purpose of this study is to evaluate the performance of the Extend system for patient repositioning before each treatment session (fraction) and patient immobilization between (interfraction) and during (intrafraction) each session in the first 10 patients (36 fractional treatments) treated at the University of Virginia. The RCT was used to acquire a set of reference measurements for each patient position at the time of CT simulation. Repositioning measurements were acquired before each fraction, and the patient position was adjusted until the residual radial difference from the reference position measurements was less than 1 mm. After treatment, patient position measurements were acquired, and the difference between those measurements and the ones obtained for patient position before the fraction was calculated as a measure of immobilization capability. Analysis of patient setup and immobilization performance included calculation of the group mean, standard deviation (SD), and distribution of systematic (components affecting all fractions) and random (per fraction) uncertainty components. Across all patients and fractions, the mean radial setup difference from the reference measurements was 0.64 mm, with an SD of 0.24 mm. The distribution of systematic uncertainty (Σ) was 0.17 mm, and the distribution of random uncertainty (σ) was 0.16 mm. The root mean square (RMS) differences for each plate of the RCT were as follows: right = 0.35 mm; left = 0.41 mm; superior = 0.28 mm

Calculation of ruin probabilities for a dense class of heavy tailed distributions

DEFF Research Database (Denmark)

Bladt, Mogens; Nielsen, Bo Friis; Samorodnitsky, Gennady

2015-01-01

In this paper, we propose a class of infinite-dimensional phase-type distributions with finitely many parameters as models for heavy tailed distributions. The class of finite-dimensional phase-type distributions is dense in the class of distributions on the positive reals and may hence approximate...... any such distribution. We prove that formulas from renewal theory, and with a particular attention to ruin probabilities, which are true for common phase-type distributions also hold true for the infinite-dimensional case. We provide algorithms for calculating functionals of interest...... such as the renewal density and the ruin probability. It might be of interest to approximate a given heavy tailed distribution of some other type by a distribution from the class of infinite-dimensional phase-type distributions and to this end we provide a calibration procedure which works for the approximation...

First study of the negative binomial distribution applied to higher moments of net-charge and net-proton multiplicity distributions

International Nuclear Information System (INIS)

Tarnowsky, Terence J.; Westfall, Gary D.

2013-01-01

A study of the first four moments (mean, variance, skewness, and kurtosis) and their products (κσ 2 and Sσ) of the net-charge and net-proton distributions in Au + Au collisions at √(s NN )=7.7–200 GeV from HIJING simulations has been carried out. The skewness and kurtosis and the collision volume independent products κσ 2 and Sσ have been proposed as sensitive probes for identifying the presence of a QCD critical point. A discrete probability distribution that effectively describes the separate positively and negatively charged particle (or proton and anti-proton) multiplicity distributions is the negative binomial (or binomial) distribution (NBD/BD). The NBD/BD has been used to characterize particle production in high-energy particle and nuclear physics. Their application to the higher moments of the net-charge and net-proton distributions is examined. Differences between κσ 2 and a statistical Poisson assumption of a factor of four (for net-charge) and 40% (for net-protons) can be accounted for by the NBD/BD. This is the first application of the properties of the NBD/BD to describe the behavior of the higher moments of net-charge and net-proton distributions in nucleus–nucleus collisions

Sensors in Distributed Mixed Reality Environments

Directory of Open Access Journals (Sweden)

Felix Hamza-Lup

2005-04-01

Full Text Available A distributed mixed-reality (MR or virtual reality (VR environment implies the cooperative engagement of a set of software and hardware resources. With the advances in sensors and computer networks we have seen an increase in the number of potential MR/VR applications that require large amounts of information from the real world collected through sensors (e.g. position and orientation tracking sensors. These sensors collect data from the real environment in real-time at different locations and a distributed environment connecting them must assure data distribution among collaborative sites at interactive speeds. With the advances in sensor technology, we envision that in future systems a significant amount of data will be collected from sensors and devices attached to the participating nodes This paper proposes a new architecture for sensor based interactive distributed MR/VR environments that falls in-between the atomistic peer-to-peer model and the traditional client-server model. Each node is autonomous and fully manages its resources and connectivity. The dynamic behavior of the nodes is dictated by the human participants that manipulate the sensors attached to these nodes.

Position list word aligned hybrid

DEFF Research Database (Denmark)

Deliege, Francois; Pedersen, Torben Bach

2010-01-01

Compressed bitmap indexes are increasingly used for efficiently querying very large and complex databases. The Word Aligned Hybrid (WAH) bitmap compression scheme is commonly recognized as the most efficient compression scheme in terms of CPU efficiency. However, WAH compressed bitmaps use a lot...... of storage space. This paper presents the Position List Word Aligned Hybrid (PLWAH) compression scheme that improves significantly over WAH compression by better utilizing the available bits and new CPU instructions. For typical bit distributions, PLWAH compressed bitmaps are often half the size of WAH...... bitmaps and, at the same time, offer an even better CPU efficiency. The results are verified by theoretical estimates and extensive experiments on large amounts of both synthetic and real-world data....

Muoniated radical states in the group 16 elements: Computational studies

International Nuclear Information System (INIS)

Macrae, Roderick M.

2009-01-01

Recent experimental studies on positive muon implantation in silicon, selenium, and tellurium have been interpreted on the basis that the primary paramagnetic species observed is XMu (X=S, Se, or Te), the muonium-substituted analog of the appropriate diatomic chalcogen monohydride radical. However, temperature-dependent signal visibility, broadening, and hyperfine shift effects remain puzzling. The interplay of degeneracy, spin-orbit coupling, and vibrational averaging in these species makes them computationally challenging despite their small size. In this work computational studies are carried out on all hydrogen isotopomers of the series OH, SH, SeH, and TeH. Several different methodological approaches are compared, and the effects of wavefunction symmetry, spin-orbit coupling, and zero-point vibrational corrections on the isotropic and anisotropic components of the hyperfine interaction are examined. Additionally, some models of the Mu site in rhombic sulfur are briefly considered.

Periodic Solution and Stationary Distribution of Stochastic Predator-Prey Models with Higher-Order Perturbation

Science.gov (United States)

Liu, Qun; Jiang, Daqing

2018-04-01

In this paper, two stochastic predator-prey models with general functional response and higher-order perturbation are proposed and investigated. For the nonautonomous periodic case of the system, by using Khasminskii's theory of periodic solution, we show that the system admits a nontrivial positive T-periodic solution. For the system disturbed by both white and telegraph noises, sufficient conditions for positive recurrence and the existence of an ergodic stationary distribution to the solutions are established. The existence of stationary distribution implies stochastic weak stability to some extent.

Distribution of the Crustal Magnetic Field in Sichuan-Yunnan Region, Southwest China

Directory of Open Access Journals (Sweden)

Chunhua Bai

2014-01-01

Full Text Available Based on the new and higher degree geomagnetic model NGDC-720-V3, we have investigated the spatial distribution, the altitude decay characteristics of the crustal magnetic anomaly, the contributions from different wavelength bands to the anomaly, and the relationship among the anomaly, the geological structure, and the geophysical field in Sichuan-Yunnan region of China. It is noted that the most outstanding feature in this area is the strong positive magnetic anomaly in Sichuan Basin, a geologically stable block. Contrasting with this feature, a strong negative anomaly can be seen nearby in Longmen Mountain block, an active block. This contradiction implies a possible relationship between the magnetic field and the geological activity. Completely different feature in magnetic field distribution is seen in the central Yunnan block, another active region, where positive and negative anomalies distribute alternatively, showing a complex magnetic anomaly map. Some fault belts, such as the Longmen Mountain fault, Lijiang-Xiaojinhe fault, and the Red River fault, are the transitional zones of strong and weak or negative and positive anomalies. The corresponding relationship between the magnetic anomaly and the geophysical fields was confirmed.

Extraction of density distributions and particle locations from hologram images

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Koji; Ikeda, Koh; Madarame, Haruki [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

1996-10-01

In this study, the simultaneous measurement technique for three-dimensional density and three-dimensional velocity distributions was evaluated. The Holographic Particle Image Velocimetry (HPIV) was the technique to record the three-dimensional position of the tracer particle on the hologram. When there were density distributions in the interrogation region, the plane optical wave may be modulated because of the difference of the refraction indices. Then, both of the plane wave modulated by density and the spherical wave by particle scatter were interfered with the reference beam, being recorded on the hologram. With reconstructing the hologram, the both of the modulated plane wave and spherical wave were reconstructed. Since the plane wave and spherical wave had low and high frequency, respectively, the two information could be separated using low-pass and high-pass filter. In the experiment, a jet of carbon-dioxide into air with mist were measured. Both mist particle position and the fringe shift caused by the density distribution were well observed, showing the effectiveness of the proposed technique. (author)

Transforming distance education curricula through distributive leadership

Directory of Open Access Journals (Sweden)

Mike Keppell

2010-12-01

Full Text Available This paper examines a core leadership strategy for transforming learning and teaching in distance education through flexible and blended learning. It focuses on a project centred on distributive leadership that involves collaboration, shared purpose, responsibility and recognition of leadership irrespective of role or position within an organisation. Distributive leadership was a core principle in facilitating the transformation of learning and teaching through a Teaching Fellowship Scheme that empowered leaders across a regional distance education university. In parallel, a design-based research project analysed the perceptions of the Teaching Fellows in relation to blended learning, time/space, peer learning, innovation and equity issues in relation to distance education.

Positive Technologies for Understanding and Promoting Positive Emotions.

Science.gov (United States)

Baños, Rosa María; Carrillo, Alba; Etchemendy, Ernestina; Botella, Cristina

2017-10-26

Information and Communication Technologies (ICTs) have become increasingly present in our lives, and their use has spread considerably. This paper presents a review of the way ICTs can help practitioners and researchers to study, promote, and train positive emotions. It is framed within the field of Positive Technologies: the applied scientific approach to the study of the use of technology to improve the quality of personal experience, with the goal of increasing wellbeing. First, the article presents an introduction to the topic of technologies and positive emotions. Then, it describes how ICTs can aid in monitoring, assessing, promoting, modifying, and training positive emotions. Finally, implications and future directions of the role of Positive Technologies in positive emotions are discussed. The authors conclude that, in the near future, Positive Technologies and the field of positive emotions will interact synergistically, producing an exponential growth in the understanding and promotion of positive emotions.

[Analysis of cis-regulatory element distribution in gene promoters of Gossypium raimondii and Arabidopsis thaliana].

Science.gov (United States)

Sun, Gao-Fei; He, Shou-Pu; Du, Xiong-Ming

2013-10-01

Cotton genomic studies have boomed since the release of Gossypium raimondii draft genome. In this study, cis-regulatory element (CRE) in 1 kb length sequence upstream 5' UTR of annotated genes were selected and scanned in the Arabidopsis thaliana (At) and Gossypium raimondii (Gr) genomes, based on the database of PLACE (Plant cis-acting Regulatory DNA Elements). According to the definition of this study, 44 (12.3%) and 57 (15.5%) CREs presented "peak-like" distribution in the 1 kb selected sequences of both genomes, respectively. Thirty-four of them were peak-like distributed in both genomes, which could be further categorized into 4 types based on their core sequences. The coincidence of TATABOX peak position and their actual position ((-) -30 bp) indicated that the position of a common CRE was conservative in different genes, which suggested that the peak position of these CREs was their possible actual position of transcription factors. The position of a common CRE was also different between the two genomes due to stronger length variation of 5' UTR in Gr than At. Furthermore, most of the peak-like CREs were located in the region of -110 bp-0 bp, which suggested that concentrated distribution might be conductive to the interaction of transcription factors, and then regulate the gene expression in downstream.

Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries

CERN Document Server

Adeva, B; Arik, E; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; De Botton, N R; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, S; Kabuss, E M; Kageya, T; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Rijllart, A; Reicherz, G; Roberts, J; Rodríguez, M; Rondio, Ewa; Roscherr, B; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zhao, J

1998-01-01

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range $0.003$1~GeV$^2$. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at $Q^2$=10~GeV$^2$. The polarised $u$ valence quark distribution, $\\Delta u_v(x)$, is positive and the polarisation increases with $x$. The polarised $d$ valence quark distribution, $\\Delta d_v(x)$, is negative and the non-strange sea distribution, $\\Delta \\bar q(x)$, is consistent with zero over the measured range of $x$. We find for the first moments $\\int_0^1 \\Delta u_v(x) {\\rm d}x = 0.77 \\pm 0.10 \\pm 0.08$, $\\int_0^1 \\Delta d_v(x) {\\rm d}x = -0.52 \\pm 0.14 \\pm 0.09$ and $\\int_0^1 \\Delta \\bar q(x) {\\rm ...

NEWTPOIS- NEWTON POISSON DISTRIBUTION PROGRAM

Science.gov (United States)

Bowerman, P. N.

1994-01-01

The cumulative poisson distribution program, NEWTPOIS, is one of two programs which make calculations involving cumulative poisson distributions. Both programs, NEWTPOIS (NPO-17715) and CUMPOIS (NPO-17714), can be used independently of one another. NEWTPOIS determines percentiles for gamma distributions with integer shape parameters and calculates percentiles for chi-square distributions with even degrees of freedom. It can be used by statisticians and others concerned with probabilities of independent events occurring over specific units of time, area, or volume. NEWTPOIS determines the Poisson parameter (lambda), that is; the mean (or expected) number of events occurring in a given unit of time, area, or space. Given that the user already knows the cumulative probability for a specific number of occurrences (n) it is usually a simple matter of substitution into the Poisson distribution summation to arrive at lambda. However, direct calculation of the Poisson parameter becomes difficult for small positive values of n and unmanageable for large values. NEWTPOIS uses Newton's iteration method to extract lambda from the initial value condition of the Poisson distribution where n=0, taking successive estimations until some user specified error term (epsilon) is reached. The NEWTPOIS program is written in C. It was developed on an IBM AT with a numeric co-processor using Microsoft C 5.0. Because the source code is written using standard C structures and functions, it should compile correctly on most C compilers. The program format is interactive, accepting epsilon, n, and the cumulative probability of the occurrence of n as inputs. It has been implemented under DOS 3.2 and has a memory requirement of 30K. NEWTPOIS was developed in 1988.

[Data distribution and transformation in population based sampling survey of viral load in HIV positive men who have sex with men in China].

Science.gov (United States)

Dou, Z; Chen, J; Jiang, Z; Song, W L; Xu, J; Wu, Z Y

2017-11-10

Objective: To understand the distribution of population viral load (PVL) data in HIV infected men who have sex with men (MSM), fit distribution function and explore the appropriate estimating parameter of PVL. Methods: The detection limit of viral load (VL) was ≤ 50 copies/ml. Box-Cox transformation and normal distribution tests were used to describe the general distribution characteristics of the original and transformed data of PVL, then the stable distribution function was fitted with test of goodness of fit. Results: The original PVL data fitted a skewed distribution with the variation coefficient of 622.24%, and had a multimodal distribution after Box-Cox transformation with optimal parameter ( λ ) of-0.11. The distribution of PVL data over the detection limit was skewed and heavy tailed when transformed by Box-Cox with optimal λ =0. By fitting the distribution function of the transformed data over the detection limit, it matched the stable distribution (SD) function ( α =1.70, β =-1.00, γ =0.78, δ =4.03). Conclusions: The original PVL data had some censored data below the detection limit, and the data over the detection limit had abnormal distribution with large degree of variation. When proportion of the censored data was large, it was inappropriate to use half-value of detection limit to replace the censored ones. The log-transformed data over the detection limit fitted the SD. The median ( M ) and inter-quartile ranger ( IQR ) of log-transformed data can be used to describe the centralized tendency and dispersion tendency of the data over the detection limit.

Plant distribution-altitude and landform relationships in karstic sinkholes of Mediterranean region of Turkey.

Science.gov (United States)

Ozkan, Kürsad; Gulsoy, Serkan; Mert, Ahmet; Ozturk, Munir; Muys, Bart

2010-01-01

The purpose of this study was to investigate the relationships between the plant distribution and the altitude-shape-size characteristics of sinkholes, and the landform characteristics inside sinkholes in the Mediterranean region of Turkey. Block kriging, Factor analysis, Cluster Analysis and Detrended Correspondence Analysis were performed. The sinkhole type and altitudinal zone were found to be the significant factors affecting the plant distribution. However, the sinkhole type was more important than the altitudinal zone. Hence, the sinkholes were first subdivided into groups according to types and then the groups were divided into subgroups according to the altitudinal zones. Consequently, 4 groups were defined; A-type sinkholes [1400-1550 m (A1), 1550-1700 m (A2)] and B-type sinkholes [1400-1550 (B1), 1550-1700 m (B2)]. The B-type was wider vertically and shorter horizontally than A-type sinkholes. Significant differences were found between the plant distribution and slope position inside the sinkholes. Plant distribution in the lower slopes was different from that in the flats and ridges in the B1 sub-type of B-type. Plant distribution in B2 subtype was different among the slope positions (ridge, middle slope, lower slope, and flat). Although distribution of plants is different in different parts (ridges, upper slope, middle slope, lower slope and basal flats) of A sinkhole, the differences between the parts of intermediate slope position are not significant. A high plant variability along short distances in the sinkholes was observed in the study area. That is why the site of sinkholes have a big potential for the distribution of many species. Hence, the area must be separated as strictly protected zone.

Factors affecting hydrogen-tunneling contribution in hydroxylation reactions promoted by oxoiron(IV) porphyrin π-cation radical complexes.

Science.gov (United States)

Cong, Zhiqi; Kinemuchi, Haruki; Kurahashi, Takuya; Fujii, Hiroshi

2014-10-06

Hydrogen atom transfer with a tunneling effect (H-tunneling) has been proposed to be involved in aliphatic hydroxylation reactions catalyzed by cytochrome P450 and synthetic heme complexes as a result of the observation of large hydrogen/deuterium kinetic isotope effects (KIEs). In the present work, we investigate the factors controlling the H-tunneling contribution to the H-transfer process in hydroxylation reaction by examining the kinetics of hydroxylation reactions at the benzylic positions of xanthene and 1,2,3,4-tetrahydronaphthalene by oxoiron(IV) 5,10,15,20-tetramesitylporphyrin π-cation radical complexes ((TMP(+•))Fe(IV)O(L)) under single-turnover conditions. The Arrhenius plots for these hydroxylation reactions of H-isotopomers have upwardly concave profiles. The Arrhenius plots of D-isotopomers, clear isosbestic points, and product analysis rule out the participation of thermally dependent other reaction processes in the concave profiles. These results provide evidence for the involvement of H-tunneling in the rate-limiting H-transfer process. These profiles are simulated using an equation derived from Bell's tunneling model. The temperature dependence of the KIE values (k(H)/k(D)) determined for these reactions indicates that the KIE value increases as the reaction temperature becomes lower, the bond dissociation energy (BDE) of the C-H bond of a substrate becomes higher, and the reactivity of (TMP(+•))Fe(IV)O(L) decreases. In addition, we found correlation of the slope of the ln(k(H)/k(D)) - 1/T plot and the bond strengths of the Fe═O bond of (TMP(+•))Fe(IV)O(L) estimated from resonance Raman spectroscopy. These observations indicate that these factors modulate the extent of the H-tunneling contribution by modulating the ratio of the height and thickness of the reaction barrier.

Experimental study on pure titanium during the positive-torsion and positive-negative-torsion

Energy Technology Data Exchange (ETDEWEB)

Chen, Han; Li, Fuguo, E-mail: fuguolx@nwpu.edu.cn; Li, Jinghui; Zhao, Zhen; Zhou, Shunshun; Wan, Qiong

2016-09-30

The results of the mechanical properties, microstructure and fracture analysis of the pure titanium deformed by positive-torsion (PT) and positive-negative-torsion (PNT) are investigated by uniaxial tensile (UT) test, micro-indentation (MI) test, optical microscope (OM), transmission electron microscope (TEM) and scanning electron microscope (SEM). The UT test indicates that the strength increases obviously with the increase of torsion radian during PT. However, the strength firstly increases quickly, and then tends to steady with the increase of deformation during PNT. The similar phenomena are also shown through MI hardness analysis. The results from geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) indicate that the dislocation density varies differently with the increase of deformation during PT and PNT. OM observation shows the grains are elongated and large numbers of deformation twins are observed during PT while the equiaxial grains are always presented during PNT. The variations of dislocation density during PT and PNT are verified by TEM. Besides, quantities of subgrains (SGs) are observed owing to the accumulated larger plastic strain during PNT while large numbers of deformation twins intersect with each other during PT. The fracture analysis indicates that large numbers of micro-voids distribute non-uniformly on fracture surface of sample twisted by PNT. However, the characteristics of ductile and brittle fracture are observed on fracture surface of sample twisted by PT.

Interaction systems design and the protocol- and middleware-centred paradigms in distributed application development

NARCIS (Netherlands)

Andrade Almeida, João; van Sinderen, Marten J.; Quartel, Dick; Ferreira Pires, Luis

2003-01-01

This paper aims at demonstrating the benefits and importance of interaction systems design in the development of distributed applications. We position interaction systems design with respect to two paradigms that have influenced the design of distributed applications: the middleware-centred and the

A network flow algorithm to position tiles for LAMOST

International Nuclear Information System (INIS)

Li Guangwei; Zhao Gang

2009-01-01

We introduce the network flow algorithm used by the Sloan Digital Sky Survey (SDSS) into the sky survey of the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST) to position tiles. Because fibers in LAMOST's focal plane are distributed uniformly, we cannot use SDSS' method directly. To solve this problem, firstly we divide the sky into many small blocks, and we also assume that all the targets that are in the same block have the same position, which is the center of the block. Secondly, we give a value to limit the number of the targets that the LAMOST focal plane can collect in one square degree so that it cannot collect too many targets in one small block. Thirdly, because the network flow algorithm used in this paper is a bipartite network, we do not use the general solution algorithm that was used by SDSS. Instead, we give our new faster solution method for this special network. Compared with the Convergent Mean Shift Algorithm, the network flow algorithm can decrease observation times with improved mean imaging quality. This algorithm also has a very fast running speed. It can distribute millions of targets in a few minutes using a common personal computer.

Beam position feedback system for the advanced photon source

International Nuclear Information System (INIS)

Chung, Y.

1994-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and x-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4 kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and x-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back to the global orbit data to the local feedback systems. The effect of the eddy current induced in the relatively thick (1/2 in.) vacuum chamber by the ac corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the x-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will also be presented

Beam position feedback system for the advanced photon source

International Nuclear Information System (INIS)

Chung, Y.

1994-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4 kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the vacuum chamber eddy current induced by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will be presented. copyright 1994 American Institute of Physics

Beam position feedback system for the Advanced Photon Source

International Nuclear Information System (INIS)

Chung, Y.

1993-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the vacuum chamber eddy current induced by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will be presented

Beam position feedback system for the Advanced Photon Source

International Nuclear Information System (INIS)

Chung, Y.

1993-01-01

The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The systems consist of 20 VME crates distributed around the ring, each running multiple digital signal processors (DSP) running at 4kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. The particle and X-ray beam position data is shared by the distributed processors through networked reflective memory. A theory of closed orbit correction using the technique of singular value decomposition (SVD) of the response matrix and simulation of its application to the APS storage ring will be discussed. This technique combines the global and local feedback systems and resolves the conflict among multiple local feedback systems due to local bump closure error. Maximum correction efficiency is achieved by feeding back the global orbit data to the local feedback systems. The effect of the eddy current induced in the relatively thick (1/2 inch) vacuum chamber by the AC corrector magnet field for local feedback systems is compensated by digital filters. Results of experiments conducted on the X-ray ring of the National Synchrotron Light Source and the SPEAR at Stanford Synchrotron Radiation Laboratory will also be presented

Wave-packet dynamics in alkaline dimers. Investigation and control through coherent excitation with fs-pulses; Wellenpaketdynamik in Alkali-Dimeren. Untersuchung und Steuerung durch kohaerente Anregung mit fs-Pulsen

Energy Technology Data Exchange (ETDEWEB)

Sauer, F.N.B.

2007-07-01

During my PhD thesis I investigated alkaline dimers with coherent control in a molecular beam as well as with pump-probe spectroscopy in a magneto-optical trap (MOT). The aim of the coherent control experiments were the isotope selective ionization with phase- and amplitude-shaped fs-pulses. Chapter 4 described the gained results of isotope selective ionization of NaK and KRb in a molecular beam by using different pulse formers. For the NaK dimer was the reached optimization factor R{sub Ph} and {sub Ampl}{sup 770}=R{sub max}/R{sub min}=25 between maximization and minimization of the isotopomer ratio ({sup 23}Na{sup 39}K){sup +}/({sup 23}Na{sup 41}K){sup +} with phase and amplitude modulation of the fs-pulse with a central wavelength of {lambda}=770 nm. From the electronic ground-state X(1){sup 1}{sigma}{sup +};{nu}''=0 transfers a one-photon-excitation population in the first excited A(2) {sup 1}{sigma}{sup +} state. The coherent control experiment on KRb was used to maximize and minimize the isotopomer ratio ({sup 124}KRb){sup +}/({sup 126}KRb){sup +}. It was the first coherent control experiment with a spectral resolution of 1.84 cm{sup -1}/Pixel. For the phase and amplitude optimization was the received optimization factor between minimization and maximization of the isotopomer ratio R{sub Ph} and {sub Ampl}=R{sub max}/R{sub min}=7 at a central wavelength of 840 nm. The results showed a stepwise excitation process from the electronic ground-state in the first excited (2){sup 1}{sigma}{sup +} state with a further excitation, that is possible over three resonant energy potential curves into the ionic ground-state. In the second part of my thesis I realized pump-probe spectroscopy of Rb{sub 2} dimers in a dark SPOT. (orig.)

Wave-packet dynamics in alkaline dimers. Investigation and control through coherent excitation with fs-pulses

International Nuclear Information System (INIS)

Sauer, F.N.B.

2007-01-01

During my PhD thesis I investigated alkaline dimers with coherent control in a molecular beam as well as with pump-probe spectroscopy in a magneto-optical trap (MOT). The aim of the coherent control experiments were the isotope selective ionization with phase- and amplitude-shaped fs-pulses. Chapter 4 described the gained results of isotope selective ionization of NaK and KRb in a molecular beam by using different pulse formers. For the NaK dimer was the reached optimization factor R Ph and Ampl 770 =R max /R min =25 between maximization and minimization of the isotopomer ratio ( 23 Na 39 K) + /( 23 Na 41 K) + with phase and amplitude modulation of the fs-pulse with a central wavelength of λ=770 nm. From the electronic ground-state X(1) 1 Σ + ;ν''=0 transfers a one-photon-excitation population in the first excited A(2) 1 Σ + state. The coherent control experiment on KRb was used to maximize and minimize the isotopomer ratio ( 124 KRb) + /( 126 KRb) + . It was the first coherent control experiment with a spectral resolution of 1.84 cm -1 /Pixel. For the phase and amplitude optimization was the received optimization factor between minimization and maximization of the isotopomer ratio R Ph and Ampl =R max /R min =7 at a central wavelength of 840 nm. The results showed a stepwise excitation process from the electronic ground-state in the first excited (2) 1 Σ + state with a further excitation, that is possible over three resonant energy potential curves into the ionic ground-state. In the second part of my thesis I realized pump-probe spectroscopy of Rb 2 dimers in a dark SPOT. (orig.)

Beyond Massive MIMO: The Potential of Positioning With Large Intelligent Surfaces