WorldWideScience

Sample records for rate limiting step

  1. The Determination of Rate-Limiting Steps during Soot Formation

    Science.gov (United States)

    1990-06-08

    and a CH3N precursor of acetonitrile such as 2H-aziridine although other intermediates of lower energy such as ketenimine have been identified on the...precursor of acetonitrile such as 2H-aziridine or ketenimine . Experimentally it was found that the overall rate of disappearance of pyrrole is first order

  2. Kinetics of protein–ligand unbinding: Predicting pathways, rates, and rate-limiting steps

    Science.gov (United States)

    Tiwary, Pratyush; Limongelli, Vittorio; Salvalaglio, Matteo; Parrinello, Michele

    2015-01-01

    The ability to predict the mechanisms and the associated rate constants of protein–ligand unbinding is of great practical importance in drug design. In this work we demonstrate how a recently introduced metadynamics-based approach allows exploration of the unbinding pathways, estimation of the rates, and determination of the rate-limiting steps in the paradigmatic case of the trypsin–benzamidine system. Protein, ligand, and solvent are described with full atomic resolution. Using metadynamics, multiple unbinding trajectories that start with the ligand in the crystallographic binding pose and end with the ligand in the fully solvated state are generated. The unbinding rate koff is computed from the mean residence time of the ligand. Using our previously computed binding affinity we also obtain the binding rate kon. Both rates are in agreement with reported experimental values. We uncover the complex pathways of unbinding trajectories and describe the critical rate-limiting steps with unprecedented detail. Our findings illuminate the role played by the coupling between subtle protein backbone fluctuations and the solvation by water molecules that enter the binding pocket and assist in the breaking of the shielded hydrogen bonds. We expect our approach to be useful in calculating rates for general protein–ligand systems and a valid support for drug design. PMID:25605901

  3. Starch hydrolysis in autogenerative high pressure digestion: Gelatinisation and saccharification as rate limiting steps

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Ding, L.; Weijma, J.; Plugge, C.M.; Lier, van J.B.

    2014-01-01

    Autogenerative high pressure digestion (AHPD) provides an integrated biogas upgrading technology, capable of producing biogas with a CH4 content exceeding 95% at pressures up to 90 bar. Hydrolysis is generally regarded as the rate-limiting step in the anaerobic digestion of complex organic matter,

  4. Pathway and rate-limiting step of glyphosate degradation by Aspergillus oryzae A-F02.

    Science.gov (United States)

    Fu, Gui-Ming; Chen, Yan; Li, Ru-Yi; Yuan, Xiao-Qiang; Liu, Cheng-Mei; Li, Bin; Wan, Yin

    2017-09-14

    Aspergillus oryzae A-F02, a glyphosate-degrading fungus, was isolated from an aeration tank in a pesticide factory. The pathway and rate-limiting step of glyphosate (GP) degradation were investigated through metabolite analysis. GP, aminomethylphosphonic acid (AMPA), and methylamine were detected in the fermentation liquid of A. oryzae A-F02, whereas sarcosine and glycine were not. The pathway of GP degradation in A. oryzae A-F02 was revealed: GP was first degraded into AMPA, which was then degraded into methylamine. Finally, methylamine was further degraded into other products. Investigating the effects of the exogenous addition of substrates and metabolites showed that the degradation of GP to AMPA is the rate-limiting step of GP degradation by A. oryzae A-F02. In addition, the accumulation of AMPA and methylamine did not cause feedback inhibition in GP degradation. Results showed that degrading GP to AMPA was a crucial step in the degradation of GP, which determines the degradation rate of GP by A. oryzae A-F02.

  5. The molecular mechanism for overcoming the rate-limiting step in monoamine neurotransmitter transport

    DEFF Research Database (Denmark)

    Sinning, Steffen; Said, Saida; Malinauskaite, Lina

    The monoamine transporter family consists of dopamine (DAT), norepinephrine (NET) and serotonin transporters (SERT) that mediate the reuptake of the monoamine neurotransmitters after their release during neurotransmission. These transporters play prominent roles in psychiatric disorders and are t......The monoamine transporter family consists of dopamine (DAT), norepinephrine (NET) and serotonin transporters (SERT) that mediate the reuptake of the monoamine neurotransmitters after their release during neurotransmission. These transporters play prominent roles in psychiatric disorders...... membrane. The rate-limiting step in monoamine reuptake is the return of the empty transporter from an inward-facing to an outward-facing conformation without neurotransmitter and sodium bound. The molecular mechanism underlying this important conformational transition has not been described. Crystal...

  6. Enzyme kinetics and identification of the rate-limiting step of enzymatic arabinoxylan degradation

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard; Xu, Cheng; Sørensen, Jens

    2012-01-01

    This study investigated the kinetics of multi-enzymatic degradation of soluble wheat arabinoxylan by monitoring the release of xylose and arabinose during designed treatments with mono-component enzymes at different substrate concentrations. The results of different combinations of α...... α-l-arabinofuranosidases catalyze liberation of arabinose residues linked 1→3 to singly (AFAn) or doubly (AFBa) substituted xyloses in arabinoxylan, respectively. When added to arabinoxylan at equimolar levels, the AFBa enzyme catalyzed the release of more arabinose, i.e. had a higher rate constant...... than AFAn, but with respect to the xylose release, AFAn – as expected – exhibited a better synergistic effect than AFBa with β-xylosidase. This synergistic effect with AFAn was estimated to increase the number of β-xylosidase catalyzed cuts from ∼3 (with β-xylosidase alone) to ∼7 in each arabinoxylan...

  7. Kinetic coupling of phosphate release, force generation and rate-limiting steps in the cross-bridge cycle.

    Science.gov (United States)

    Stehle, Robert; Tesi, Chiara

    2017-08-01

    A basic goal in muscle research is to understand how the cyclic ATPase activity of cross-bridges is converted into mechanical force. A direct approach to study the chemo-mechanical coupling between P i release and the force-generating step is provided by the kinetics of force response induced by a rapid change in [P i ]. Classical studies on fibres using caged-P i discovered that rapid increases in [P i ] induce fast force decays dependent on final [P i ] whose kinetics were interpreted to probe a fast force-generating step prior to P i release. However, this hypothesis was called into question by studies on skeletal and cardiac myofibrils subjected to P i jumps in both directions (increases and decreases in [P i ]) which revealed that rapid decreases in [P i ] trigger force rises with slow kinetics, similar to those of calcium-induced force development and mechanically-induced force redevelopment at the same [P i ]. A possible explanation for this discrepancy came from imaging of individual sarcomeres in cardiac myofibrils, showing that the fast force decay upon increase in [P i ] results from so-called sarcomere 'give'. The slow force rise upon decrease in [P i ] was found to better reflect overall sarcomeres cross-bridge kinetics and its [P i ] dependence, suggesting that the force generation coupled to P i release cannot be separated from the rate-limiting transition. The reasons for the different conclusions achieved in fibre and myofibril studies are re-examined as the recent findings on cardiac myofibrils have fundamental consequences for the coupling between P i release, rate-limiting steps and force generation. The implications from P i -induced force kinetics of myofibrils are discussed in combination with historical and recent models of the cross-bridge cycle.

  8. Reorientation of the Methyl Group in MAs(III) is the Rate-Limiting Step in the ArsM As(III) S-Adenosylmethionine Methyltransferase Reaction.

    Science.gov (United States)

    Packianathan, Charles; Li, Jiaojiao; Kandavelu, Palani; Sankaran, Banumathi; Rosen, Barry P

    2018-03-01

    The most common biotransformation of trivalent inorganic arsenic (As(III)) is methylation to mono-, di-, and trimethylated species. Methylation is catalyzed by As(III) S -adenosylmethionine (SAM) methyltransferase (termed ArsM in microbes and AS3MT in animals). Methylarsenite (MAs(III)) is both the product of the first methylation step and the substrate of the second methylation step. When the rate of the overall methylation reaction was determined with As(III) as the substrate, the first methylation step was rapid, whereas the second methylation step was slow. In contrast, when MAs(III) was used as the substrate, the rate of methylation was as fast as the first methylation step when As(III) was used as the substrate. These results indicate that there is a slow conformational change between the first and second methylation steps. The structure of CmArsM from the thermophilic alga Cyanidioschyzon merolae sp. 5508 was determined with bound MAs(III) at 2.27 Å resolution. The methyl group is facing the solvent, as would be expected when MAs(III) is bound as the substrate rather than facing the SAM-binding site, as would be expected for MAs(III) as a product. We propose that the rate-limiting step in arsenic methylation is slow reorientation of the methyl group from the SAM-binding site to the solvent, which is linked to the conformation of the side chain of a conserved residue Tyr70.

  9. Deuterium isotope effects on toluene metabolism. Product release as a rate-limiting step in cytochrome P-450 catalysis

    International Nuclear Information System (INIS)

    Ling, K.H.; Hanzlik, R.P.

    1989-01-01

    Liver microsomes from phenobarbital-induced rats oxidize toluene to a mixture of benzyl alcohol plus o-, m- and p-cresol (ca. 69:31). Stepwise deuteration of the methyl group causes stepwise decreases in the yield of benzyl alcohol relative to cresols (ca. 24:76 for toluene-d3). For benzyl alcohol formation from toluene-d3 DV = 1.92 and D(V/K) = 3.53. Surprisingly, however, stepwise deuteration induces stepwise increases in total oxidation, giving rise to an inverse isotope effect overall (DV = 0.67 for toluene-d3). Throughout the series (i.e. d0, d1, d2, d3) the ratios of cresol isomers remain constant. These results are interpreted in terms of product release for benzyl alcohol being slower than release of cresols (or their epoxide precursors), and slow enough to be partially rate-limiting in turnover. Thus metabolic switching to cresol formation causes a net acceleration of turnover

  10. Tartronate semialdehyde reductase defines a novel rate-limiting step in assimilation and bioconversion of glycerol in Ustilago maydis.

    Directory of Open Access Journals (Sweden)

    Yanbin Liu

    Full Text Available BACKGROUND: Glycerol is a by-product of biodiesel production. Currently, it has limited applications with low bioconversion efficiency to most metabolites reported. This is partly attributed to the poor knowledge on the glycerol metabolic pathway in bacteria and fungi. METHODOLOGY/PRINCIPAL FINDINGS: We have established a fast screening method for identification of genes that improve glycerol utilization in Ustilago maydis. This was done by comparing the growth rates of T-DNA tagged mutant colonies on solid medium using glycerol as the sole carbon source. We present a detailed characterization of one of the mutants, GUM1, which contains a T-DNA element inserted into the promoter region of UM02592 locus (MIPS Ustilago maydis database, MUMDB, leading to enhanced and constitutive expression of its mRNA. We have demonstrated that um02592 encodes a functional tartronate semialdehyde reductase (Tsr1, which showed dual specificity to cofactors NAD(+ and NADP(+ and strong substrate specificity and enantioselectivity for D-glycerate. Improved glycerol assimilation in GUM1 was associated with elevated expression of tsr1 mRNA and this could be phenocopied by over-expression of the gene. Glycolipid accumulation was reduced by 45.2% in the knockout mutant whereas introduction of an extra copy of tsr1 driven by the glyceraldehyde phosphate dehydrogenase promoter increased it by 40.4%. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that tartronate semialdehyde reductase (TSR plays an important role in glycerol assimilation in U. maydis and defines a novel target in genetic engineering for improved conversion of glycerol to higher value products. Our results add significant depth to the understanding of the glycerol metabolic pathway in fungi. We have demonstrated, for the first time, a biological role of a eukaryotic TSR.

  11. Nature of rate-limiting steps in a compartmentalized enzyme system. Quantitation of dopamine transport and hydroxylation rates in resealed chromaffin granule ghosts

    International Nuclear Information System (INIS)

    Ahn, N.G.; Klinman, J.P.

    1989-01-01

    Using isolated chromaffin granule ghosts from bovine adrenal medullae, we have studied the kinetics of dopamine beta-monooxygenase (D beta M) activity as it is linked to dopamine transport. Measurements of the initial rates of transport and of transport-linked norepinephrine formation suggested that enzyme activity may be partially rate-limiting in the coupled carrier/enzyme system. This was confirmed by (i) measurements of initial rates of norepinephrine formation using deuterated substrate, which gave isotope effects greater than 2.0, and (ii) kinetic measurements using ghosts pulsed with varying concentrations of labeled dopamine, which indicated substantial substrate accumulation in the vesicle interior as a function of time. Initial rates of product formation, when combined with approximations of internal substrate concentrations, allowed estimates of Kcat and Km for intravesicular D beta M. Activation by external reductant was apparent in both initial rate parameters and the measurements of transients. Under conditions of optimal D beta M activity, the enzyme rate parameters (kcat = 0.31 nmol/s.mg and Km = 2 mM) indicated partial rate limitation compared to dopamine transport (kcat = 0.38 nmol/s.mg and Km = 32 microM). Compartmental analysis of the time curves, performed using numerical nonlinear least squares methods, gave least squares estimates of rate constants for a simple carrier mechanism and kcat values for D beta M which were consistent with estimates from initial rates

  12. Kinetic mechanism of human DNA ligase I reveals magnesium-dependent changes in the rate-limiting step that compromise ligation efficiency.

    Science.gov (United States)

    Taylor, Mark R; Conrad, John A; Wahl, Daniel; O'Brien, Patrick J

    2011-07-01

    DNA ligase I (LIG1) catalyzes the ligation of single-strand breaks to complete DNA replication and repair. The energy of ATP is used to form a new phosphodiester bond in DNA via a reaction mechanism that involves three distinct chemical steps: enzyme adenylylation, adenylyl transfer to DNA, and nick sealing. We used steady state and pre-steady state kinetics to characterize the minimal mechanism for DNA ligation catalyzed by human LIG1. The ATP dependence of the reaction indicates that LIG1 requires multiple Mg(2+) ions for catalysis and that an essential Mg(2+) ion binds more tightly to ATP than to the enzyme. Further dissection of the magnesium ion dependence of individual reaction steps revealed that the affinity for Mg(2+) changes along the reaction coordinate. At saturating concentrations of ATP and Mg(2+) ions, the three chemical steps occur at similar rates, and the efficiency of ligation is high. However, under conditions of limiting Mg(2+), the nick-sealing step becomes rate-limiting, and the adenylylated DNA intermediate is prematurely released into solution. Subsequent adenylylation of enzyme prevents rebinding to the adenylylated DNA intermediate comprising an Achilles' heel of LIG1. These ligase-generated 5'-adenylylated nicks constitute persistent breaks that are a threat to genomic stability if they are not repaired. The kinetic and thermodynamic framework that we have determined for LIG1 provides a starting point for understanding the mechanism and specificity of mammalian DNA ligases.

  13. The influence of drug distribution and drug-target binding on target occupancy : The rate-limiting step approximation

    NARCIS (Netherlands)

    Witte, de W.E.A.; Vauquelin, G.; Graaf, van der P.H.; Lange, de E.C.M.

    2017-01-01

    The influence of drug-target binding kinetics on target occupancy can be influenced by drug distribution and diffusion around the target, often referred to as "rebinding" or "diffusion-limited binding". This gives rise to a decreased decline of the drug-target complex concentration as a result of a

  14. Locating the rate-limiting step for the interaction of hydrogen with Mg(0001) using density-functional theory calculations and rate theory

    DEFF Research Database (Denmark)

    Vegge, Tejs

    2004-01-01

    The dissociation of molecular hydrogen on a Mgs0001d surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate is investigated using Density Functional Theory (DFT) calculations and rate theory. The minimum energy path and corresponding transition states are located usi...... to be rate-limiting for the ab- and desorption of hydrogen, respectively. Zero-point energy contributions are found to be substantial for the diffusion of atomic hydrogen, but classical rates are still found to be within an order of magnitude at room temperature.......The dissociation of molecular hydrogen on a Mgs0001d surface and the subsequent diffusion of atomic hydrogen into the magnesium substrate is investigated using Density Functional Theory (DFT) calculations and rate theory. The minimum energy path and corresponding transition states are located using...

  15. The single-process biochemical reaction of Rubisco: a unified theory and model with the effects of irradiance, CO₂ and rate-limiting step on the kinetics of C₃ and C₄ photosynthesis from gas exchange.

    Science.gov (United States)

    Farazdaghi, Hadi

    2011-02-01

    Photosynthesis is the origin of oxygenic life on the planet, and its models are the core of all models of plant biology, agriculture, environmental quality and global climate change. A theory is presented here, based on single process biochemical reactions of Rubisco, recognizing that: In the light, Rubisco activase helps separate Rubisco from the stored ribulose-1,5-bisphosphate (RuBP), activates Rubisco with carbamylation and addition of Mg²(+), and then produces two products, in two steps: (Step 1) Reaction of Rubisco with RuBP produces a Rubisco-enediol complex, which is the carboxylase-oxygenase enzyme (Enco) and (Step 2) Enco captures CO₂ and/or O₂ and produces intermediate products leading to production and release of 3-phosphoglycerate (PGA) and Rubisco. PGA interactively controls (1) the carboxylation-oxygenation, (2) electron transport, and (3) triosephosphate pathway of the Calvin-Benson cycle that leads to the release of glucose and regeneration of RuBP. Initially, the total enzyme participates in the two steps of the reaction transitionally and its rate follows Michaelis-Menten kinetics. But, for a continuous steady state, Rubisco must be divided into two concurrently active segments for the two steps. This causes a deviation of the steady state from the transitional rate. Kinetic models are developed that integrate the transitional and the steady state reactions. They are tested and successfully validated with verifiable experimental data. The single-process theory is compared to the widely used two-process theory of Farquhar et al. (1980. Planta 149, 78-90), which assumes that the carboxylation rate is either Rubisco-limited at low CO₂ levels such as CO₂ compensation point, or RuBP regeneration-limited at high CO₂. Since the photosynthesis rate cannot increase beyond the two-process theory's Rubisco limit at the CO₂ compensation point, net photosynthesis cannot increase above zero in daylight, and since there is always respiration at

  16. Neutral pumping rates for a next step tokamak ignition device

    International Nuclear Information System (INIS)

    Galambos, J.D.; Peng, Y.K.M.; Heifetz, D.

    1985-01-01

    Neutral pumping rates are calculated for pump-limiter and divertor options of a next step tokamak ignition device using a method that accounts for the coupled effects of neutral transport and plasma transport. For both pump limiters and divertors the plasma flow into the channel surrounding the neutralizer plate is greatly reduced by the neutral recycling. The fraction of this flow that is pumped can be large (>50%) but in general is dependent on the particular geometry and plasma conditions. It is estimated that pumping speeds greater than or approximately 10 5 L/s are adequate for the exhaust requirements in the pump-limiter and the divertor cases

  17. Increasing preferred step rate during running reduces plantar pressures.

    Science.gov (United States)

    Gerrard, James M; Bonanno, Daniel R

    2018-01-01

    Increasing preferred step rate during running is a commonly used strategy in the management of running-related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty-two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar-X in-shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kPa; P=.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P=.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P=.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kPa; P=.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P=.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Increasing Running Step Rate Reduces Patellofemoral Joint Forces

    Science.gov (United States)

    Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

    2013-01-01

    Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

  19. Valuing Euro rating-triggered step-up telecom bonds

    NARCIS (Netherlands)

    P. Houweling (Patrick); A.A. Mentink; A.C.F. Vorst (Ton)

    2003-01-01

    textabstractWe value rating-triggered step-up bonds with three methods: (i) the Jarrow, Lando and Turnbull (1997, JLT) framework, (ii) a similar framework using historical probabilities and (iii) as plain vanilla bonds. We find that the market seems to value single step-up bonds according to the JLT

  20. Valuing Euro Rating-Triggered Step-Up Telecom Bonds

    NARCIS (Netherlands)

    P. Houweling (Patrick); A.A. Mentink; A.C.F. Vorst (Ton)

    2003-01-01

    textabstractWe value rating-triggered step-up bonds with three methods: (i) the Jarrow, Lando and Turnbull (1997, JLT) framework, (ii) a similar framework using historical probabilities and (iii) as plain vanilla bonds. We find that the market seems to value single step-up bonds according to the JLT

  1. Time step size limitation introduced by the BSSN Gamma Driver

    Energy Technology Data Exchange (ETDEWEB)

    Schnetter, Erik, E-mail: schnetter@cct.lsu.ed [Department of Physics and Astronomy, Louisiana State University, LA (United States)

    2010-08-21

    Many mesh refinement simulations currently performed in numerical relativity counteract instabilities near the outer boundary of the simulation domain either by changes to the mesh refinement scheme or by changes to the gauge condition. We point out that the BSSN Gamma Driver gauge condition introduces a time step size limitation in a similar manner as a Courant-Friedrichs-Lewy condition, but which is independent of the spatial resolution. We give a didactic explanation of this issue, show why, especially, mesh refinement simulations suffer from it, and point to a simple remedy. (note)

  2. Analysis of reaction schemes using maximum rates of constituent steps

    Science.gov (United States)

    Motagamwala, Ali Hussain; Dumesic, James A.

    2016-01-01

    We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, rmax,i, assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of rmax,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of rmax,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps. PMID:27162366

  3. Effects of step rate manipulation on joint mechanics during running.

    Science.gov (United States)

    Heiderscheit, Bryan C; Chumanov, Elizabeth S; Michalski, Max P; Wille, Christa M; Ryan, Michael B

    2011-02-01

    the objective of this study was to characterize the biomechanical effects of step rate modification during running on the hip, knee, and ankle joints so as to evaluate a potential strategy to reduce lower extremity loading and risk for injury. three-dimensional kinematics and kinetics were recorded from 45 healthy recreational runners during treadmill running at constant speed under various step rate conditions (preferred, ± 5%, and ± 10%). We tested our primary hypothesis that a reduction in energy absorption by the lower extremity joints during the loading response would occur, primarily at the knee, when step rate was increased. less mechanical energy was absorbed at the knee (P running and may prove beneficial in the prevention and treatment of common running-related injuries.

  4. Biological effect of Pulsed Dose Rate brachytherapy with stepping sources

    International Nuclear Information System (INIS)

    Limbergen, Erik F.M. van; Fowler, Jack F.

    1996-01-01

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR), for local tissue dose-rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. An earlier publication (Fowler and Mount 1992) had shown that, for dose rates (averaged for the duration of the pulse) up to 3 Gy/h, little change of isoeffect doses from continuous low dose rate (CLDR) are expected, unless larger doses per fraction than 1 Gy are used, and especially if components of very rapid repair are present with half-times of less than about 0.5 hours. However, local and transient dose rates close to stepping sources can be up to several Gy per minute. Methods: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to repair, at a constant exponential rate. The formula developed by Dale for fractionated low-dose-rate radiotherapy was used. A constant overall time of 140 hours and constant total dose of 70 Gy were assumed throughout, the continuous low dose-rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose-rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, and T (1(2)) from 4 minutes to 1.5 hours. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (> 1 Gy) at high instantaneous dose-rates if T (1(2)) in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in the tissue, and - when T (1(2)) is short - the instantaneous dose-rate. Maximum ratios of PDR/CLDR effect occur when the dose-rate is such that pulse duration is approximately equal to T (1(2)) of repair. Results are presented for late-responding tissues, the differences from CLDR

  5. Modelling the bioconversion of cellulose into microbial products: rate limitations

    Energy Technology Data Exchange (ETDEWEB)

    Asenjo, J A

    1984-12-01

    The direct bioconversion of cellulose into microbial products carried out as a simultaneous saccharification and fermentation has a strong effect on the rates of cellulose degradation because cellobiose and glucose inhibition of the reaction are circumvented. A general mathematical model of the kinetics of this bioconversion has been developed. Its use in representing aerobic systems and in the analysis of the kinetic limitations has been investigated. Simulations have been carried out to find the rate limiting steps in slow fermentations and in rapid ones as determined by the specific rate of product formation. The requirements for solubilising and depolymerising enzyme activities (cellulase and cellobiase) in these systems has been determined. The activity that have been obtained for fungal cellulases are adequate for the kinetic requirements of the fastest fermentative strains. The results also show that for simultaneous bioconversions where strong cellobiose and glucose inhibition is overcome, no additional cellobiase is necessary to increase the rate of product formation. These results are useful for the selection of cellolytic micro-organisms and in the determination of enzymes to be cloned in recombinant strains. 17 references.

  6. Stability analysis and time-step limits for a Monte Carlo Compton-scattering method

    International Nuclear Information System (INIS)

    Densmore, Jeffery D.; Warsa, James S.; Lowrie, Robert B.

    2010-01-01

    A Monte Carlo method for simulating Compton scattering in high energy density applications has been presented that models the photon-electron collision kinematics exactly [E. Canfield, W.M. Howard, E.P. Liang, Inverse Comptonization by one-dimensional relativistic electrons, Astrophys. J. 323 (1987) 565]. However, implementing this technique typically requires an explicit evaluation of the material temperature, which can lead to unstable and oscillatory solutions. In this paper, we perform a stability analysis of this Monte Carlo method and develop two time-step limits that avoid undesirable behavior. The first time-step limit prevents instabilities, while the second, more restrictive time-step limit avoids both instabilities and nonphysical oscillations. With a set of numerical examples, we demonstrate the efficacy of these time-step limits.

  7. 48 CFR 352.231-70 - Salary rate limitation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Salary rate limitation... Salary rate limitation. As prescribed in 331.101-70, the Contracting Officer shall insert the following clause: Salary Rate Limitation (January 2010) (a) Pursuant to the current and applicable prior HHS...

  8. 13 CFR 120.315 - Interest rate and loan limit.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Interest rate and loan limit. 120... Special Purpose Loans Disabled Assistance Loan Program (dal) § 120.315 Interest rate and loan limit. The interest rate on direct DAL loans is three percent. There is an administrative limit of $150,000 on a...

  9. Step driven competitive epitaxial and self-limited growth of graphene on copper surface

    Directory of Open Access Journals (Sweden)

    Lili Fan

    2011-09-01

    Full Text Available The existence of surface steps was found to have significant function and influence on the growth of graphene on copper via chemical vapor deposition. The two typical growth modes involved were found to be influenced by the step morphologies on copper surface, which led to our proposed step driven competitive growth mechanism. We also discovered a protective role of graphene in preserving steps on copper surface. Our results showed that wide and high steps promoted epitaxial growth and yielded multilayer graphene domains with regular shape, while dense and low steps favored self-limited growth and led to large-area monolayer graphene films. We have demonstrated that controllable growth of graphene domains of specific shape and large-area continuous graphene films are feasible.

  10. Three-minute constant rate step test for detecting exertional dyspnea relief after bronchodilation in COPD

    Directory of Open Access Journals (Sweden)

    Borel B

    2016-11-01

    Full Text Available Benoit Borel,1,2 Courtney A Wilkinson-Maitland,3 Alan Hamilton,4 Jean Bourbeau,5 Hélène Perrault,6 Dennis Jensen,3,5,7 François Maltais2 1Laboratoire HAVAE, Université de Limoges, Limoges, France; 2Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, 3Clinical Exercise and Respiratory Physiology Laboratory, Department of Kinesiology and Physical Education, McGill University, Montréal, QC, 4Boehringer Ingelheim (Canada Limited, Burlington, ON, 5Respiratory Epidemiology and Clinical Research Unit, Montreal Chest Institute, McGill University Health Center, Montreal, QC, 6Faculty of Health Sciences, University of Ottawa, Ottawa, ON, 7Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada Background: The aim of this study was to evaluate the responsiveness of the 3-minute constant rate step test (3-MST to detect the relief of exertional dyspnea (respiratory discomfort after acute bronchodilation in COPD patients. Patients and methods: A total of 40 patients with moderate-to-severe COPD (mean forced expiratory volume in 1 second: 45.7 (±14.7, % predicted performed four 3-MSTs at randomly assigned stepping rates of 14, 16, 20 and 24 steps/min after inhalation of nebulized ipratropium bromide (500 µg/salbutamol (2.5 mg and saline placebo, which were randomized to order. Patients rated their intensity of perceived dyspnea at the end of each 3-MST using Borg 0–10 category ratio scale. Results: A total of 37 (92.5%, 36 (90%, 34 (85% and 27 (67.5% patients completed all 3 minutes of exercise at 14, 16, 20 and 24 steps/min under both treatment conditions, respectively. Compared with placebo, ipratropium bromide/salbutamol significantly decreased dyspnea at the end of the third minute of exercise at 14 steps/min (by 0.6±1.0 Borg 0–10 scale units, P<0.01 and 16 steps/min (by 0.7±1.3 Borg 0–10 scale

  11. THE EFFECT OF STEP RATE MANIPULATION ON FOOT STRIKE PATTERN OF LONG DISTANCE RUNNERS.

    Science.gov (United States)

    Allen, Darrell J; Heisler, Hollie; Mooney, Jennifer; Kring, Richard

    2016-02-01

    Running gait retraining to change foot strike pattern in runners from a heel strike pattern to a non heel- strike pattern has been shown to reduce impact forces and may help to reduce running related injuries. Step rate manipulation above preferred is known to help decrease step length, foot inclination angle, and vertical mass excursion, but has not yet been evaluated as a method to change foot strike pattern. The purpose of this study was to investigate the effect of step rate manipulation on foot strike pattern in shod recreational runners who run with a heel strike pattern. A secondary purpose was to describe the effect of step rate manipulation at specific percentages above preferred on foot inclination angle at initial contact. Forty volunteer runners, who were self-reported heel strikers and had a weekly running mileage of at least 10 miles, were recruited. Runners were confirmed to be heel strikers during the warm up period on the treadmill. The subject's step rate was determined at their preferred running pace. A metronome was used to increase step rate above the preferred step rate by 5%, 10% and 15%. 2D video motion analysis was utilized to determine foot strike pattern and to measure foot inclination angle at initial contact for each step rate condition. There was a statistically significant change in foot strike pattern from a heel strike pattern to a mid-foot or forefoot strike pattern at both 10% and 15% step rates above preferred. Seven of the 40 subjects (17.5%) changed from a heel- strike pattern to a non- heel strike pattern at +10% and 12 of the 40 subjects (30%) changed to a non-heel strike pattern at +15%. Mean foot inclination angle at initial contact showed a statistically significant change (reduction) as step rate increased. Step rate manipulation of 10% or greater may be enough to change foot strike pattern from a heel strike to a mid-foot or forefoot strike pattern in a small percentage of recreational runners who run in traditional

  12. 39 CFR 3010.25 - Limitation on unused rate adjustment authority rate adjustments.

    Science.gov (United States)

    2010-07-01

    ... only be applied together with inflation-based limitation rate adjustments or when inflation-based... used in lieu of an inflation-based limitation rate adjustment. ... 39 Postal Service 1 2010-07-01 2010-07-01 false Limitation on unused rate adjustment authority...

  13. 48 CFR 331.101-70 - Salary rate limitation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Salary rate limitation... CONTRACTING REQUIREMENTS CONTRACT COST PRINCIPLES AND PROCEDURES Applicability 331.101-70 Salary rate... used to pay the direct salary of an individual at a rate in excess of the Federal Executive Schedule...

  14. Charts for specifying limits on copper stabilizer damage rate

    International Nuclear Information System (INIS)

    Sawan, M.E.

    1984-01-01

    Charts that simplify the task of specifying the damage rate limit in the copper stabilizer of fusion reactor superconducting magnets are presented. Partial damage recovery with annealing is accounted for. Applications to the MARS magnets are discussed. (orig.)

  15. Improved sugar-free succinate production by Synechocystis sp. PCC 6803 following identification of the limiting steps in glycogen catabolism

    Directory of Open Access Journals (Sweden)

    Tomohisa Hasunuma

    2016-12-01

    Full Text Available Succinate produced by microorganisms can replace currently used petroleum-based succinate but typically requires mono- or poly-saccharides as a feedstock. The cyanobacterium Synechocystis sp. PCC6803 can produce organic acids such as succinate from CO2 not supplemented with sugars under dark anoxic conditions using an unknown metabolic pathway. The TCA cycle in cyanobacteria branches into oxidative and reductive routes. Time-course analyses of the metabolome, transcriptome and metabolic turnover described here revealed dynamic changes in the metabolism of Synechocystis sp. PCC6803 cultivated under dark anoxic conditions, allowing identification of the carbon flow and rate-limiting steps in glycogen catabolism. Glycogen biosynthesized from CO2 assimilated during periods of light exposure is catabolized to succinate via glycolysis, the anaplerotic pathway, and the reductive TCA cycle under dark anoxic conditions. Expression of the phosphoenolpyruvate (PEP carboxylase gene (ppc was identified as a rate-limiting step in succinate biosynthesis and this rate limitation was alleviated by ppc overexpression, resulting in improved succinate excretion. The sugar-free succinate production was further enhanced by the addition of bicarbonate. In vivo labeling with NaH13CO3 clearly showed carbon incorporation into succinate via the anaplerotic pathway. Bicarbonate is in equilibrium with CO2. Succinate production by Synechocystis sp. PCC6803 therefore holds significant promise for CO2 capture and utilization. Keywords: Autofermentation, Cyanobacteria, Dynamic metabolic profiling, Metabolomics, Succinate, Synechocystis

  16. Stabilization of a three-dimensional limit cycle walking model through step-to-step ankle control.

    Science.gov (United States)

    Kim, Myunghee; Collins, Steven H

    2013-06-01

    Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss of active ankle control. If ankle control can contribute significantly to maintaining balance, even in the presence of active foot placement, this might provide an opportunity to improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods in a three-dimensional model of human gait that included ankle plantarflexion, ankle inversion-eversion, hip flexion-extension, and hip ad/abduction. We generated discrete feedback control laws (linear quadratic regulators) that altered nominal actuation parameters once per step. We used ankle push-off, lateral ankle stiffness and damping, fore-aft foot placement, lateral foot placement, or all of these as control inputs. We modeled environmental disturbances as random, bounded, unexpected changes in floor height, and defined balance performance as the maximum allowable disturbance value for which the model walked 500 steps without falling. Nominal walking motions were unstable, but were stabilized by all of the step-to-step control laws we tested. Surprisingly, step-by-step modulation of ankle push-off alone led to better balance performance (3.2% leg length) than lateral foot placement (1.2% leg length) for these control laws. These results suggest that appropriate control of robotic ankle-foot prosthesis push-off could make balancing during walking easier for individuals with amputation.

  17. A lower limit for the birth rate of pulsars

    International Nuclear Information System (INIS)

    Narayan, R.; Vivekanand, M.

    1981-01-01

    Using experimental data on observed pulsars, a lower limit for the birth rate of pulsars in our galaxy was estimated, taking into account the beam factor which allows for the possibility that only a fraction of all pulsars is beamed towards the earth. The calculation reduces the discrepancy between pulsar and supernova birth rates. (U.K.)

  18. Comparison between a pumped-limiter and a divertor for the next step machines

    International Nuclear Information System (INIS)

    Harrison, F.F.A.

    1985-01-01

    The paper presents a simple description of the physics issues which influence the conceptual design of a pumped-limiter and single-null poloidal divertor in a next step, long burn tokamak of NET/INTOR scale. Predicted performance of the limiter and divertor are compared in regard to localised recycling, sputtering of the plasma collection surfaces, penetration of sputtered impurities into the fusion plasma, surface power loading and exhaust of helium ash. It is concluded that the performance of the divertor is superior and that it can be predicted with a reasonable degree of confidence. The viability of the limiter remains in doubt but the concept cannot be rejected at the present time

  19. Two-Step Process for ED UTI Screening in Febrile Young Children: Reducing Catheterization Rates.

    Science.gov (United States)

    Lavelle, Jane M; Blackstone, Mercedes M; Funari, Mary Kate; Roper, Christine; Lopez, Patricia; Schast, Aileen; Taylor, April M; Voorhis, Catherine B; Henien, Mira; Shaw, Kathy N

    2016-07-01

    Urinary tract infection (UTI) screening in febrile young children can be painful and time consuming. We implemented a screening protocol for UTI in a high-volume pediatric emergency department (ED) to reduce urethral catheterization, limiting catheterization to children with positive screens from urine bag specimens. This quality-improvement initiative was implemented using 3 Plan-Do-Study-Act cycles, beginning with a small test of the proposed change in 1 ED area. To ensure appropriate patients received timely screening, care teams discussed patient risk factors and created patient-specific, appropriate procedures. The intervention was extended to the entire ED after providing education. Finally, visual cues were added into the electronic health record, and nursing scripts were developed to enlist family participation. A time-series design was used to study the impact of the 6-month intervention by using a p-chart to determine special cause variation. The primary outcome measure for the study was defined as the catheterization rate in febrile children ages 6 to 24 months. The ED reduced catheterization rates among febrile young children from 63% to UTIs among those followed within the hospital's network. A 2-step less-invasive process for screening febrile young children for UTI can be instituted in a high-volume ED without increasing length of stay or missing cases of UTI. Copyright © 2016 by the American Academy of Pediatrics.

  20. Maximum organic carbon limits at different melter feed rates (U)

    International Nuclear Information System (INIS)

    Choi, A.S.

    1995-01-01

    This report documents the results of a study to assess the impact of varying melter feed rates on the maximum total organic carbon (TOC) limits allowable in the DWPF melter feed. Topics discussed include: carbon content; feed rate; feed composition; melter vapor space temperature; combustion and dilution air; off-gas surges; earlier work on maximum TOC; overview of models; and the results of the work completed

  1. Response of Microbial Soil Carbon Mineralization Rates to Oxygen Limitations

    Science.gov (United States)

    Keiluweit, M.; Denney, A.; Nico, P. S.; Fendorf, S. E.

    2014-12-01

    The rate of soil organic matter (SOM) mineralization is known to be controlled by climatic factors as well as molecular structure, mineral-organic associations, and physical protection. What remains elusive is to what extent oxygen (O2) limitations impact overall rates of microbial SOM mineralization (oxidation) in soils. Even within upland soils that are aerobic in bulk, factors limiting O2 diffusion such as texture and soil moisture can result in an abundance of anaerobic microsites in the interior of soil aggregates. Variation in ensuing anaerobic respiration pathways can further impact SOM mineralization rates. Using a combination of (first) aggregate model systems and (second) manipulations of intact field samples, we show how limitations on diffusion and carbon bioavailability interact to impose anaerobic conditions and associated respiration constraints on SOM mineralization rates. In model aggregates, we examined how particle size (soil texture) and amount of dissolved organic carbon (bioavailable carbon) affect O2 availability and distribution. Monitoring electron acceptor profiles (O2, NO3-, Mn and Fe) and SOM transformations (dissolved, particulate, mineral-associated pools) across the resulting redox gradients, we then determined the distribution of operative microbial metabolisms and their cumulative impact on SOM mineralization rates. Our results show that anaerobic conditions decrease SOM mineralization rates overall, but those are partially offset by the concurrent increases in SOM bioavailability due to transformations of protective mineral phases. In intact soil aggregates collected from soils varying in texture and SOM content, we mapped the spatial distribution of anaerobic microsites. Optode imaging, microsensor profiling and 3D tomography revealed that soil texture regulates overall O2 availability in aggregate interiors, while particulate SOM in biopores appears to control the fine-scale distribution of anaerobic microsites. Collectively, our

  2. The limiting dose rate and its importance in radiation protection

    International Nuclear Information System (INIS)

    Bakkiam, D.; Sonwani, Swetha; Arul Ananthakumar, A.; Mohankumar, Mary N.

    2012-01-01

    The concept of defining a low dose of ionizing radiation still remains unclear. Before attempting to define a low dose, it is more important to define a low-dose rate since effects at low dose-rates are different from those observed at higher dose-rates. Hence, it follows that low dose-rates rather than a low dose is an important criteria to determine radio-biological effects and risk factors i.e. stochastic health effects. Chromosomal aberrations induced by ionizing radiations are well fitted by quadratic model Y= áD + âD 2 + C with the linear coefficient of dose predominating for high LET radiations and low doses of low LET. At higher doses and dose rates of sparsely ionizing radiation, break pairs produced by inter-track action leads to the formation of exchange type aberrations and is dependent on dose rate. Whereas at lower doses and dose rates, intra-track action produces break pairs and resulting aberrations are in direct proportion to absorbed dose and independent of dose rate. The dose rate at which inter-track ceases to be observable and where intra-track action effectively becomes the sole contributor of lesion-pair formation is referred to as limiting dose rate (LDR). Once the LDR is reached further reduction in dose rates will not affect the slope of DR since breaks produced by independent charged particle tracks are widely separated in time to interact with each other for aberration yield. This linear dependency is also noticed for acute exposures at very low doses. Existing reports emphasizes the existence of LDR likely to be e6.3cGyh -1 . However no systematic studies have been conducted so far to determine LDR. In the present investigation DR curves were constructed for the dose rates 0.002 and 0.003 Gy/min and to define LDR at which a coefficient approaches zero. Extrapolation of limiting low dose rate data can be used to predict low dose effects regardless of dose rate and its definition ought to serve as a useful index for studies pertaining

  3. Detection limit for rate fluctuations in inhomogeneous Poisson processes

    Science.gov (United States)

    Shintani, Toshiaki; Shinomoto, Shigeru

    2012-04-01

    Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

  4. Detection limit for rate fluctuations in inhomogeneous Poisson processes.

    Science.gov (United States)

    Shintani, Toshiaki; Shinomoto, Shigeru

    2012-04-01

    Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

  5. Shutdown Dose Rate Analysis Using the Multi-Step CADIS Method

    International Nuclear Information System (INIS)

    Ibrahim, Ahmad M.; Peplow, Douglas E.; Peterson, Joshua L.; Grove, Robert E.

    2015-01-01

    The Multi-Step Consistent Adjoint Driven Importance Sampling (MS-CADIS) hybrid Monte Carlo (MC)/deterministic radiation transport method was proposed to speed up the shutdown dose rate (SDDR) neutron MC calculation using an importance function that represents the neutron importance to the final SDDR. This work applied the MS-CADIS method to the ITER SDDR benchmark problem. The MS-CADIS method was also used to calculate the SDDR uncertainty resulting from uncertainties in the MC neutron calculation and to determine the degree of undersampling in SDDR calculations because of the limited ability of the MC method to tally detailed spatial and energy distributions. The analysis that used the ITER benchmark problem compared the efficiency of the MS-CADIS method to the traditional approach of using global MC variance reduction techniques for speeding up SDDR neutron MC calculation. Compared to the standard Forward-Weighted-CADIS (FW-CADIS) method, the MS-CADIS method increased the efficiency of the SDDR neutron MC calculation by 69%. The MS-CADIS method also increased the fraction of nonzero scoring mesh tally elements in the space-energy regions of high importance to the final SDDR

  6. The rate-limiting process of hydrogen transport in Mo

    Energy Technology Data Exchange (ETDEWEB)

    Ohkoshi, Keishiro; Chikazawa, Yoshitaka; Bandourko, V; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen isotope transport characteristics of Mo, whose refractory properties are considered to be suitable as plasma facing material, was investigated by applying 3 keV D{sub 2}{sup +} beam to the membrane specimen. The Arrhenius plot of deuterium permeation probability showed linear increase against the reciprocal temperature and its apparent activation energy was determined as 41.5 kJ/mol. The simultaneous irradiation of 3 keV Ar{sup +} onto backside surface of specimen had little effect on the deuterium permeation rate. According to these results, the rate-limiting process of deuterium transport in Mo was determined. (author)

  7. Determination of the mass transfer limiting step of dye adsorption onto commercial adsorbent by using mathematical models.

    Science.gov (United States)

    Marin, Pricila; Borba, Carlos Eduardo; Módenes, Aparecido Nivaldo; Espinoza-Quiñones, Fernando R; de Oliveira, Silvia Priscila Dias; Kroumov, Alexander Dimitrov

    2014-01-01

    Reactive blue 5G dye removal in a fixed-bed column packed with Dowex Optipore SD-2 adsorbent was modelled. Three mathematical models were tested in order to determine the limiting step of the mass transfer of the dye adsorption process onto the adsorbent. The mass transfer resistance was considered to be a criterion for the determination of the difference between models. The models contained information about the external, internal, or surface adsorption limiting step. In the model development procedure, two hypotheses were applied to describe the internal mass transfer resistance. First, the mass transfer coefficient constant was considered. Second, the mass transfer coefficient was considered as a function of the dye concentration in the adsorbent. The experimental breakthrough curves were obtained for different particle diameters of the adsorbent, flow rates, and feed dye concentrations in order to evaluate the predictive power of the models. The values of the mass transfer parameters of the mathematical models were estimated by using the downhill simplex optimization method. The results showed that the model that considered internal resistance with a variable mass transfer coefficient was more flexible than the other ones and this model described the dynamics of the adsorption process of the dye in the fixed-bed column better. Hence, this model can be used for optimization and column design purposes for the investigated systems and similar ones.

  8. Probing the Rate-Determining Step of the Claisen-Schmidt Condensation by Competition Reactions

    Science.gov (United States)

    Mak, Kendrew K. W.; Chan, Wing-Fat; Lung, Ka-Ying; Lam, Wai-Yee; Ng, Weng-Cheong; Lee, Siu-Fung

    2007-01-01

    Competition experiments are a useful tool for preliminary study of the linear free energy relationship of organic reactions. This article describes a physical organic experiment for upper-level undergraduates to identify the rate-determining step of the Claisen-Schmidt condensation of benzaldehyde and acetophenone by studying the linear free…

  9. On the limitations of fixed-step-size adaptive methods with response confidence.

    Science.gov (United States)

    Hsu, Yung-Fong; Chin, Ching-Lan

    2014-05-01

    The family of (non-parametric, fixed-step-size) adaptive methods, also known as 'up-down' or 'staircase' methods, has been used extensively in psychophysical studies for threshold estimation. Extensions of adaptive methods to non-binary responses have also been proposed. An example is the three-category weighted up-down (WUD) method (Kaernbach, 2001) and its four-category extension (Klein, 2001). Such an extension, however, is somewhat restricted, and in this paper we discuss its limitations. To facilitate the discussion, we characterize the extension of WUD by an algorithm that incorporates response confidence into a family of adaptive methods. This algorithm can also be applied to two other adaptive methods, namely Derman's up-down method and the biased-coin design, which are suitable for estimating any threshold quantiles. We then discuss via simulations of the above three methods the limitations of the algorithm. To illustrate, we conduct a small scale of experiment using the extended WUD under different response confidence formats to evaluate the consistency of threshold estimation. © 2013 The British Psychological Society.

  10. Two steps forward, one step back: Achievements and limitations of university-community partnerships in addressing neighbourhood socioeconomic disadvantage

    Directory of Open Access Journals (Sweden)

    Deborah Warr

    2016-09-01

    Full Text Available This article discusses a partnership initiative that involved a major Australian research university (University of Melbourne, a local government and a network of local community service organisations. The partnership projects aimed to promote public access to university infrastructure for poor and marginalised residents, enhance the local value of research and teaching activities, and create employment opportunities. The article draws on an evaluation of the partnership, which focused on four keynote projects. It found that the partnership appeared to achieve positive outcomes for residents but was limited by tensions associated with the university’s ambivalent commitment to the value of such partnerships. These tensions remained difficult to resolve because they signalled present contestation over the foundational values of contemporary public universities. Keywords: university-community partnerships, neoliberalism, neighbourhoods, community development

  11. Physiological effects of bioceramic material: harvard step, resting metabolic rate and treadmill running assessments.

    Science.gov (United States)

    Leung, Ting-Kai; Kuo, Chia-Hua; Lee, Chi-Ming; Kan, Nai-Wen; Hou, Chien-Wen

    2013-12-31

    Previous biomolecular and animal studies have shown that a room-temperature far-infrared-rayemitting ceramic material (bioceramic) demonstrates physical-biological effects, including the normalization of psychologically induced stress-conditioned elevated heart rate in animals. In this clinical study, the Harvard step test, the resting metabolic rate (RMR) assessment and the treadmill running test were conducted to evaluate possible physiological effects of the bioceramic material in human patients. The analysis of heart rate variability (HRV) during the Harvard step test indicated that the bioceramic material significantly increased the high-frequency (HF) power spectrum. In addition, the results of RMR analysis suggest that the bioceramic material reduced oxygen consumption (VO2). Our results demonstrate that the bioceramic material has the tendency to stimulate parasympathetic responses, which may reduce resting energy expenditure and improve cardiorespiratory recovery following exercise.

  12. Rate-limiting events in hyperthermic cell killing

    International Nuclear Information System (INIS)

    Landry, J.; Marceau, N.

    1978-01-01

    The inactivation rate of HeLa cells for temperatures ranging from 41 to 55 0 C and treatment durations varying from 2 to 300 min was analyzed in thermodynamic terms by considering the dependence of cell free energy (ΔG + ) on temperature. Within this temperature range the loss of proliferative capacity exhibits a complex temperature dependence which is characterized by entropy and enthalpy values that gradually decrease as temperature increases. This complex process of heat-induced cell killing was postulated to be the result of a series of reactions, each of them being alternatively rate limiting within a certain temperature range. From this kinetic scheme a mathematical model was derived and, in the case of HeLa cells, the use of a least-squares search parameter procedure (as applied to the derived survival regression function) demonstrated that three such sequential reactions were sufficient to explain all experimental data points obtained within the 41 to 55 0 C range. The proposed model was also shown to be adequate for explaining survival data of HeLa cells exposed to nanosecond heat pulses of infrared laser energy. Considerations of thermodynamic properties of known biochemical reactions suggest plausible rate-limiting events in hyperthermic cell killing

  13. Benzoylformate analogues exhibit differential rate-determining steps in the benzoylformate decarboxylase reaction

    International Nuclear Information System (INIS)

    Garcia, G.A.; Weiss, P.M.; Cook, P.F.; Kenyon, G.L.; Cleland, W.W.

    1987-01-01

    Benzoylformate decarboxylase from Pseudomonas putida is a thiamine pyrophosphate (TPP)-dependent enzyme which converts benzoylformate to benzaldehyde and CO 2 . The rate-determining step(s) in the benzoylformate decarboxylase reaction for a series of substituted benzoylformates (p-CH 3 O, p-CH 3 , p-Cl, and m-F) were studied using solvent deuterium and 13 C kinetic isotope effects. The normal substrate was found to have two partially rate-determining steps; initial tetrahedral adduct formation (D 2 O-sensitive) and decarboxylation ( 13 C-sensitive). D 2 O and 13 C isotope effects indicate that electron-withdrawing substituents (p-Cl and m-F) remove the rate dependence upon decarboxylation such that only a D 2 O effect on (V/K) is observed. Conversely, electron-donating substituents increase the rate-dependence upon decarboxylation such that a larger 13 (V/K) is seen while the D 2 O effects on (V) and (V/K) are not dramatically different from those for benzoylformate. All of the data are consistent with substituent stabilization or destabilization of the carbanionic intermediate formed upon decarboxylation

  14. Phenomenon of quantum low temperature limit of chemical reaction rates

    International Nuclear Information System (INIS)

    Gol'danskij, V.I.

    1975-01-01

    The influence of quantum-mechanical effects on one of the fundamental laws of chemical kinetics - the Arrhenius law - is considered. Criteria characterising the limits of the low-temperature region where the extent of quantum-mechanical tunnelling transitions exceeds exponentially the transitions over the barrier are quoted. Studies of the low-temperature tunnelling of electrons and hydrogen atoms are briefly mentioned and the history of research on low-temperature radiation-induced solid-phase polymerisation, the development of which led to the discovery of the phenomenon of the low-temperature quantum-mechanical limit for the rates of chemical reactions in relation to the formaldehyde polymerisation reaction, is briefly considered. The results of experiments using low-inertia calorimeters, whereby it is possible to determine directly the average time (tau 0 ) required to add one new link to the polymer chain of formaldehyde during its polymerisation by radiation and during postpolymerisation and to establish that below 80K the increase of tau 0 slows down and that at T approximately equal to 10-4K the time tau 0 reaches a plateau (tau 0 approximately equals 0.01s), are described. Possible explanations of the observed low-temperature limit for the rate of a chemical reaction are critically examined and a semiquantitative explanation is given for this phenomenon, which may be particularly common in combined electronic-confirmational transitions in complex biological molecules and may play a definite role in chemical and biological evolution (cold prehistory of life)

  15. Phenomenon of quantum low temperature limit of chemical reaction rates

    Energy Technology Data Exchange (ETDEWEB)

    Gol' danskii, V I [AN SSSR, Moscow. Inst. Khimicheskoj Fiziki

    1975-12-01

    The influence of quantum-mechanical effects on one of the fundamental laws of chemical kinetics - the Arrhenius Law - is considered. Criteria characterising the limits of the low-temperature region where the extent of quantum-mechanical tunnelling transitions exceeds exponentially the transitions over the barrier are quoted. Studies of the low-temperature tunnelling of electrons and hydrogen atoms are briefly mentioned and the history of research on low-temperature radiation-induced solid-phase polymerization, the development of which led to the discovery of the phenomenon of the low-temperature quantum-mechanical limit for the rates of chemical reactions in relation to the formaldehyde polymerization reaction, is briefly considered. The results of experiments using low-inertia calorimeters, whereby it is possible to determine directly the average time (tau/sub 0/) required to add one new link to the polymer chain of formaldehyde during its polymerization by radiation and during postpolymerization and to establish that below 80K the increase of tau/sub 0/ slows down and that at T approximately equal to 10-4K the time tau/sub 0/ reaches a plateau (tau/sub 0/ approximately equals 0.01s), are described. Possible explanations of the observed low-temperature limit for the rate of a chemical reaction are critically examined and a semiquantitative explanation is given for this phenomenon, which may be particularly common in combined electronic-confirmational transitions in complex biological molecules and may play a definite role in chemical and biological evolution (cold prehistory of life).

  16. Influence of step rate and quadriceps load distribution on patellofemoral cartilage contact pressures during running.

    Science.gov (United States)

    Lenhart, Rachel L; Smith, Colin R; Vignos, Michael F; Kaiser, Jarred; Heiderscheit, Bryan C; Thelen, Darryl G

    2015-08-20

    Interventions used to treat patellofemoral pain in runners are often designed to alter patellofemoral mechanics. This study used a computational model to investigate the influence of two interventions, step rate manipulation and quadriceps strengthening, on patellofemoral contact pressures during running. Running mechanics were analyzed using a lower extremity musculoskeletal model that included a knee with six degree-of-freedom tibiofemoral and patellofemoral joints. An elastic foundation model was used to compute articular contact pressures. The lower extremity model was scaled to anthropometric dimensions of 22 healthy adults, who ran on an instrumented treadmill at 90%, 100% and 110% of their preferred step rate. Numerical optimization was then used to predict the muscle forces, secondary tibiofemoral kinematics and all patellofemoral kinematics that would generate the measured primary hip, knee and ankle joint accelerations. Mean and peak patella contact pressures reached 5.0 and 9.7MPa during the midstance phase of running. Increasing step rate by 10% significantly reduced mean contact pressures by 10.4% and contact area by 7.4%, but had small effects on lateral patellar translation and tilt. Enhancing vastus medialis strength did not substantially affect pressure magnitudes or lateral patellar translation, but did shift contact pressure medially toward the patellar median ridge. Thus, the model suggests that step rate tends to primarily modulate the magnitude of contact pressure and contact area, while vastus medialis strengthening has the potential to alter mediolateral pressure locations. These results are relevant to consider in the design of interventions used to prevent or treat patellofemoral pain in runners. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Potentials and Limitations of Real-Time Elastography for Prostate Cancer Detection: A Whole-Mount Step Section Analysis

    Directory of Open Access Journals (Sweden)

    Daniel Junker

    2012-01-01

    Full Text Available Objectives. To evaluate prostate cancer (PCa detection rates of real-time elastography (RTE in dependence of tumor size, tumor volume, localization and histological type. Materials and Methods. Thirdy-nine patients with biopsy proven PCa underwent RTE before radical prostatectomy (RPE to assess prostate tissue elasticity, and hard lesions were considered suspicious for PCa. After RPE, the prostates were prepared as whole-mount step sections and were compared with imaging findings for analyzing PCa detection rates. Results. RTE detected 6/62 cancer lesions with a maximum diameter of 0–5 mm (9.7%, 10/37 with a maximum diameter of 6–10 mm (27%, 24/34 with a maximum diameter of 11–20 20 mm (70.6%, 14/14 with a maximum diameter of >20 mm (100% and 40/48 with a volume ≥0.2 cm3 (83.3%. Regarding cancer lesions with a volume ≥ 0.2 cm³ there was a significant difference in PCa detection rates between Gleason scores with predominant Gleason pattern 3 compared to those with predominant Gleason pattern 4 or 5 (75% versus 100%; P=0.028. Conclusions. RTE is able to detect PCa of significant tumor volume and of predominant Gleason pattern 4 or 5 with high confidence, but is of limited value in the detection of small cancer lesions.

  18. Oxidative removal of quinclorac by permanganate through a rate-limiting [3 + 2] cycloaddition reaction.

    Science.gov (United States)

    Song, Dean; Cheng, Hanyang; Jiang, Xiaohua; Sun, Huiqing; Kong, Fanyu; Liang, Rongning; Qiang, Zhimin; Liu, Huijuan; Qu, Jiuhui

    2018-04-05

    Quinclorac, a widely used herbicide in agriculture, has been recognized as an emerging environmental pollutant owing to its long persistence and potential risk to humans. However, no related information is available on the degradation of quinclorac by employing oxidants. Herein, the reactivity of quinclorac with permanganate was systematically investigated in water by combining experimental and computational approaches. The reaction followed overall second-order kinetics pointing to a bimolecular rate-limiting step. The second-order rate constant was found to be 3.47 × 10-3 M-1 s-1 at 25 °C, which was independent of pH over the range from 5 to 9 and was dependent on temperature over the range from 19 to 35 °C. The initial product was identified by UPLC-Q-TOF-MS to be mono-hydroxylated quinclorac, which was more susceptible to further oxidation. The result could be supported by the complete simulation of the reaction process in DFT calculations, indicating the [3 + 2] cycloaddition oxidation of the benzene ring in the rate-limiting step. The plausible mechanism was then proposed, accompanied by the analysis of the HOMO indicating the hydroxylation position and of the ESP suggesting a more electron-rich moiety. Considering the high effectiveness and low toxicity, permanganate oxidation was considered to be a very promising technique for removing quinclorac from aquatic environments.

  19. Dose Rate Experiment at JET for Benchmarking the Calculation Direct One Step Method

    International Nuclear Information System (INIS)

    Angelone, M.; Petrizzi, L.; Pillon, M.; Villari, R.; Popovichev, S.

    2006-01-01

    Neutrons produced by D-D and D-T plasmas induce the activation of tokamak materials and of components. The development of reliable methods to assess dose rates is a key issue for maintenance and operating nuclear machines, in normal and off-normal conditions. In the frame of the EFDA Fusion Technology work programme, a computational tool based upon MCNP Monte Carlo code has been developed to predict the dose rate after shutdown: it is called Direct One Step Method (D1S). The D1S is an innovative approach in which the decay gammas are coupled to the neutrons as in the prompt case and they are transported in one single step in the same run. Benchmarking of this new tool with experimental data taken in a complex geometry like that of a tokamak is a fundamental step to test the reliability of the D1S method. A dedicated benchmark experiment was proposed for the 2005-2006 experimental campaign of JET. Two irradiation positions have been selected for the benchmark: one inner position inside the vessel, not far from the plasma, called the 2 upper irradiation end (IE2), where neutron fluence is relatively high. The second position is just outside a vertical port in an external position (EX). Here the neutron flux is lower and the dose rate to be measured is not very far from the residual background. Passive detectors are used for in-vessel measurements: the high sensitivity Thermo Luminescent Dosimeters (TLDs) GR-200A (natural LiF), which ensure measurements down to environmental dose level. An active detector of Geiger-Muller (GM) type is used for out of vessel dose rate measurement. Before their use the detectors were calibrated in a secondary gamma-ray standard (Cs-137 and Co-60) facility in term of air-kerma. The background measurement was carried-out in the period July -September 2005 in the outside position EX using the GM tube and in September 2005 inside the vacuum vessel using TLD detectors located in the 2 Upper irradiation end IE2. In the present work

  20. Energy density and rate limitations in structural composite supercapacitors

    Science.gov (United States)

    Snyder, J. F.; Gienger, E.; Wetzel, E. D.; Xu, K.

    2012-06-01

    The weight and volume of conventional energy storage technologies greatly limits their performance in mobile platforms. Traditional research efforts target improvements in energy density to reduce device size and mass. Enabling a device to perform additional functions, such as bearing mechanical load, is an alternative approach as long as the total mass efficiency exceeds that of the individual materials it replaces. Our research focuses on structural composites that function as batteries and supercapacitors. These multifunctional devices could be used to replace conventional structural components, such as vehicle frame elements, to provide significant system-level weight reductions and extend mission times. Our approach is to design structural properties directly into the electrolyte and electrode materials. Solid polymer electrolyte materials bind the system and transfer load to the fibers while conducting ions between the electrodes. Carbon fiber electrodes provide a route towards optimizing both energy storage and load-bearing capabilities, and may also obviate the need for a separate current collector. The components are being integrated using scalable, cost-effective composite processing techniques that are amenable to complex part shapes. Practical considerations of energy density and rate behavior are described here as they relate to materials used. Our results highlight the viability as well as the challenges of this multifunctional approach towards energy storage.

  1. Individual adaptation to experimental changes in running speed and step rate during treadmill running in injury-free runners

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Kjeldsen, Nikolaj Hørby; Stoklund Pedersen, Daniel

    % velocity with self-selected and 105% step rate and 100% velocity with 105% step rate) and 2 sides (left and right) were analyzed by RM- ANOVA with a Greenhouse-Geisser correction and significance level 0.05 in IBM SPSS version 22.0 Results A 2-way RM-ANOVA including sides (left and right) and conditions (5...

  2. Limited Investigation of the Effects of Elevator Rate Limiting and Stick Dynamics on Longitudinal Pilot Induced Oscillations (HAVE GRIP)

    National Research Council Canada - National Science Library

    Peters, Patrick

    1996-01-01

    This report presents the results of the HAVE GRIP flight test program. This program performed a limited investigation of the effects of stick dynamics and elevator rate limiting on longitudinal pilot induced oscillations (PIOs...

  3. Hydrothermal decomposition of industrial jarosite in alkaline media: The rate determining step of the process kinetics

    Directory of Open Access Journals (Sweden)

    González-Ibarra A.A.

    2016-01-01

    Full Text Available This work examines the role of NaOH and Ca(OH2 on the hydrothermal decomposition of industrial jarosite deposited by a Mexican company in a tailings dam. The industrial jarosite is mainly composed by natrojarosite and contains 150 g Ag/t, showing a narrow particle size distribution, as revealed by XRD, fire assay, SEM-EDS and laser-diffraction analysis. The effect of the pH, when using NaOH or Ca(OH2 as alkalinizing agent was studied by carrying out decomposition experiments at different pH values and 60°C in a homogeneous size particle system (pH = 8, 9, 10 and 11 and in a heterogeneous size particle system (pH = 11. Also, the kinetic study of the process and the controlling step of the decomposition reaction when NaOH and Ca(OH2 are used was determined by fitting the data obtained to the shrinking core model for spherical particles of constant size. These results, supported by chemical (EDS, morphological (SEM and mapping of elements (EDS analysis of a partially reacted jarosite particle allowed to conclude that when NaOH is used, the process kinetics is controlled by the chemical reaction and when Ca(OH2 is used, the rate determining step is changed to a diffusion control through a layer of solid products.

  4. High mutation rates limit evolutionary adaptation in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Kathleen Sprouffske

    2018-04-01

    Full Text Available Mutation is fundamental to evolution, because it generates the genetic variation on which selection can act. In nature, genetic changes often increase the mutation rate in systems that range from viruses and bacteria to human tumors. Such an increase promotes the accumulation of frequent deleterious or neutral alleles, but it can also increase the chances that a population acquires rare beneficial alleles. Here, we study how up to 100-fold increases in Escherichia coli's genomic mutation rate affect adaptive evolution. To do so, we evolved multiple replicate populations of asexual E. coli strains engineered to have four different mutation rates for 3000 generations in the laboratory. We measured the ability of evolved populations to grow in their original environment and in more than 90 novel chemical environments. In addition, we subjected the populations to whole genome population sequencing. Although populations with higher mutation rates accumulated greater genetic diversity, this diversity conveyed benefits only for modestly increased mutation rates, where populations adapted faster and also thrived better than their ancestors in some novel environments. In contrast, some populations at the highest mutation rates showed reduced adaptation during evolution, and failed to thrive in all of the 90 alternative environments. In addition, they experienced a dramatic decrease in mutation rate. Our work demonstrates that the mutation rate changes the global balance between deleterious and beneficial mutational effects on fitness. In contrast to most theoretical models, our experiments suggest that this tipping point already occurs at the modest mutation rates that are found in the wild.

  5. Overcoming the rate-distance limit of quantum key distribution without quantum repeaters.

    Science.gov (United States)

    Lucamarini, M; Yuan, Z L; Dynes, J F; Shields, A J

    2018-05-01

    Quantum key distribution (QKD) 1,2 allows two distant parties to share encryption keys with security based on physical laws. Experimentally, QKD has been implemented via optical means, achieving key rates of 1.26 megabits per second over 50 kilometres of standard optical fibre 3 and of 1.16 bits per hour over 404 kilometres of ultralow-loss fibre in a measurement-device-independent configuration 4 . Increasing the bit rate and range of QKD is a formidable, but important, challenge. A related target, which is currently considered to be unfeasible without quantum repeaters 5-7 , is overcoming the fundamental rate-distance limit of QKD 8 . This limit defines the maximum possible secret key rate that two parties can distil at a given distance using QKD and is quantified by the secret-key capacity of the quantum channel 9 that connects the parties. Here we introduce an alternative scheme for QKD whereby pairs of phase-randomized optical fields are first generated at two distant locations and then combined at a central measuring station. Fields imparted with the same random phase are 'twins' and can be used to distil a quantum key. The key rate of this twin-field QKD exhibits the same dependence on distance as does a quantum repeater, scaling with the square-root of the channel transmittance, irrespective of who (malicious or otherwise) is in control of the measuring station. However, unlike schemes that involve quantum repeaters, ours is feasible with current technology and presents manageable levels of noise even on 550 kilometres of standard optical fibre. This scheme is a promising step towards overcoming the rate-distance limit of QKD and greatly extending the range of secure quantum communications.

  6. High mutation rates limit evolutionary adaptation in Escherichia coli

    Science.gov (United States)

    Wagner, Andreas

    2018-01-01

    Mutation is fundamental to evolution, because it generates the genetic variation on which selection can act. In nature, genetic changes often increase the mutation rate in systems that range from viruses and bacteria to human tumors. Such an increase promotes the accumulation of frequent deleterious or neutral alleles, but it can also increase the chances that a population acquires rare beneficial alleles. Here, we study how up to 100-fold increases in Escherichia coli’s genomic mutation rate affect adaptive evolution. To do so, we evolved multiple replicate populations of asexual E. coli strains engineered to have four different mutation rates for 3000 generations in the laboratory. We measured the ability of evolved populations to grow in their original environment and in more than 90 novel chemical environments. In addition, we subjected the populations to whole genome population sequencing. Although populations with higher mutation rates accumulated greater genetic diversity, this diversity conveyed benefits only for modestly increased mutation rates, where populations adapted faster and also thrived better than their ancestors in some novel environments. In contrast, some populations at the highest mutation rates showed reduced adaptation during evolution, and failed to thrive in all of the 90 alternative environments. In addition, they experienced a dramatic decrease in mutation rate. Our work demonstrates that the mutation rate changes the global balance between deleterious and beneficial mutational effects on fitness. In contrast to most theoretical models, our experiments suggest that this tipping point already occurs at the modest mutation rates that are found in the wild. PMID:29702649

  7. The Vice: Some Historically Inspired and Proof-Generated Steps to Limits of Sequences

    Science.gov (United States)

    Burn, Bob

    2005-01-01

    This paper proposes a genetic development of the concept of limit of a sequence leading to a definition, through a succession of proofs rather than through a succession of sequences or a succession of epsilons. The major ideas on which it is based are historical and depend on Euclid, Archimedes, Fermat, Wallis and Newton. Proofs of equality by…

  8. Phosphoryl transfer is not rate-limiting for the ROCK I-catalyzed kinase reaction.

    Science.gov (United States)

    Futer, Olga; Saadat, Ahmad R; Doran, John D; Raybuck, Scott A; Pazhanisamy, S

    2006-06-27

    Rho-associated coiled-coil kinase, ROCK, is implicated in Rho-mediated cell adhesion and smooth muscle contraction. Animal models suggest that the inhibition of ROCK can ameliorate conditions, such as vasospasm, hypertension, and inflammation. As part of our effort to design novel inhibitors of ROCK, we investigated the kinetic mechanism of ROCK I. Steady-state bisubstrate kinetics, inhibition kinetics, isotope partition analysis, viscosity effects, and presteady-state kinetics were used to explore the kinetic mechanism. Plots of reciprocals of initial rates obtained in the presence of nonhydrolyzable ATP analogues and the small molecule inhibitor of ROCK, Y-27632, against the reciprocals of the peptide concentrations yielded parallel lines (uncompetitive pattern). This pattern is indicative of an ordered binding mechanism, with the peptide adding first. The staurosporine analogue K252a, however, gave a noncompetitive pattern. When a pulse of (33)P-gamma-ATP mixed with ROCK was chased with excess unlabeled ATP and peptide, 0.66 enzyme equivalent of (33)P-phosphate was incorporated into the product in the first turnover. The presence of ATPase activity coupled with the isotope partition data is a clear evidence for the existence of a viable [E-ATP] complex in the kinase reaction and implicates a random binding mechanism. The k(cat)/K(m) parameters were fully sensitive to viscosity (viscosity effects of 1.4 +/- 0.2 and 0.9 +/- 0.3 for ATP and peptide 5, respectively), and therefore, the barriers to dissociation of either substrate are higher than the barrier for the phosphoryl transfer step. As a consequence, not all the binding steps are at fast equilibrium. The observation of a burst in presteady-state kinetics (k(b) = 10.2 +/- 2.1 s(-)(1)) and the viscosity effect on k(cat) of 1.3 +/- 0.2 characterize the phosphoryl transfer step to be fast and the release of product and/or the enzyme isomerization step accompanying it as rate-limiting at V(max) conditions. From

  9. The limiting distribution of extremal exchange rate yields

    NARCIS (Netherlands)

    M.C.A.B. Hols (Martien); C.G. de Vries (Casper)

    1991-01-01

    textabstractSeveral nonnested fat-tailed distributions have been advocated for modelling exchange rate returns. Instead of directly estimating these nonnested distributions we investigate the extremal distribution of the returns. The advantage is that the parameter which characterizes the amount of

  10. The Cadherin Interaction as a Rate Limiting Step in Breast Cancer Metastasis to the Liver

    National Research Council Canada - National Science Library

    Chao, Yvonne

    2008-01-01

    .... Epithelial-cadherin (E-cadherin), the prototype classical cadherin present on the surface of most epithelial cells, has a cytoplasmic domain that anchors the cell adhesion molecule to the actin cytoskeleton via catenin-based complexes...

  11. Nitrogen uptake and rate-limiting step in low-temperature nitriding of iron

    NARCIS (Netherlands)

    Inia, DK; Vredenberg, AM; Habraken, FHPM; Boerma, DO

    1999-01-01

    Recently, a method to nitride iron in NH3 ambients at low temperature (225-350 degrees C) has been developed. In this method, the Fe is covered with a thin (similar to 40 nm) Ni layer, which acts as a catalyst for the nitriding process. From experiments, in which the amount of nitrogen uptake is

  12. A stochastic step model of replicative senescence explains ROS production rate in ageing cell populations.

    Directory of Open Access Journals (Sweden)

    Conor Lawless

    Full Text Available Increases in cellular Reactive Oxygen Species (ROS concentration with age have been observed repeatedly in mammalian tissues. Concomitant increases in the proportion of replicatively senescent cells in ageing mammalian tissues have also been observed. Populations of mitotic human fibroblasts cultured in vitro, undergoing transition from proliferation competence to replicative senescence are useful models of ageing human tissues. Similar exponential increases in ROS with age have been observed in this model system. Tracking individual cells in dividing populations is difficult, and so the vast majority of observations have been cross-sectional, at the population level, rather than longitudinal observations of individual cells.One possible explanation for these observations is an exponential increase in ROS in individual fibroblasts with time (e.g. resulting from a vicious cycle between cellular ROS and damage. However, we demonstrate an alternative, simple hypothesis, equally consistent with these observations which does not depend on any gradual increase in ROS concentration: the Stochastic Step Model of Replicative Senescence (SSMRS. We also demonstrate that, consistent with the SSMRS, neither proliferation-competent human fibroblasts of any age, nor populations of hTERT overexpressing human fibroblasts passaged beyond the Hayflick limit, display high ROS concentrations. We conclude that longitudinal studies of single cells and their lineages are now required for testing hypotheses about roles and mechanisms of ROS increase during replicative senescence.

  13. A stochastic step model of replicative senescence explains ROS production rate in ageing cell populations.

    Science.gov (United States)

    Lawless, Conor; Jurk, Diana; Gillespie, Colin S; Shanley, Daryl; Saretzki, Gabriele; von Zglinicki, Thomas; Passos, João F

    2012-01-01

    Increases in cellular Reactive Oxygen Species (ROS) concentration with age have been observed repeatedly in mammalian tissues. Concomitant increases in the proportion of replicatively senescent cells in ageing mammalian tissues have also been observed. Populations of mitotic human fibroblasts cultured in vitro, undergoing transition from proliferation competence to replicative senescence are useful models of ageing human tissues. Similar exponential increases in ROS with age have been observed in this model system. Tracking individual cells in dividing populations is difficult, and so the vast majority of observations have been cross-sectional, at the population level, rather than longitudinal observations of individual cells.One possible explanation for these observations is an exponential increase in ROS in individual fibroblasts with time (e.g. resulting from a vicious cycle between cellular ROS and damage). However, we demonstrate an alternative, simple hypothesis, equally consistent with these observations which does not depend on any gradual increase in ROS concentration: the Stochastic Step Model of Replicative Senescence (SSMRS). We also demonstrate that, consistent with the SSMRS, neither proliferation-competent human fibroblasts of any age, nor populations of hTERT overexpressing human fibroblasts passaged beyond the Hayflick limit, display high ROS concentrations. We conclude that longitudinal studies of single cells and their lineages are now required for testing hypotheses about roles and mechanisms of ROS increase during replicative senescence.

  14. Influence of the incremental step size in work rate on exercise response and gas exchange in patients with pulmonary hypertension.

    Science.gov (United States)

    Gläser, Sven; Lodziewski, Sven; Koch, Beate; Opitz, Christian F; Völzke, Henry; Ewert, Ralf

    2008-02-23

    Cardiopulmonary exercise testing (CPET) has become increasingly important as a routine procedure in daily clinical work. So far, it is generally accepted that an individualized exercise protocol with exercise duration of 6 to 12 minutes is preferable to assess maximal exercise performance. The aim of this study was to compare an individualized NYHA adapted exercise protocol with a fixed standard protocol in patients with severe pulmonary arterial hypertension. Twenty-two patients (17 female, 5 male; mean age 49 +/- 14 yrs) underwent symptom limited CPET on a bicycle. On two consecutive days each subject performed a stepwise CPET according to a modified Jones protocol (16 Watt per minute stages) as well as an individualized NYHA adapted protocol with 5 or 10 Watt/min stages in a randomized order. Oxygen uptake at peak exercise (peakVO2) and anaerobic threshold (VO2AT), maximal ventilation (VE), breathing reserve (VE/MVV), ventilatory efficiency (VE vs. VCO2 slope), exercise time, maximal power and work rate were assessed and compared between both protocols. Comparing both, adapted NYHA protocol and standardized Jones protocol, we found significant differences in maximal power (56.7 +/- 19 W vs. 74 +/- 18 W; p rate, VE, VE/MVV, peakVO2, VO2AT and VE vs. VCO2 slope. Variations of incremental step size during CPET significantly affect exercise time and maximal power, whereas relevant parameters for clinical judgement and prognosis such as oxygen uptake, ventilation and ventilatory efficiency remain unchanged. These findings have practical implications for the exercise evaluation of patients with pulmonary hypertension. To reach maximal results for ventilation, oxygen uptake and gas exchange an individualization of incremental step size appears not to be mandatory.

  15. Investigating rate-limiting barriers to nanoscale nonviral gene transfer with nanobiophotonics

    Science.gov (United States)

    Chen, Hunter H.

    Nucleic acids are a novel class of therapeutics poised to address many unmet clinical needs. Safe and efficient delivery remains a significant challenge that has delayed the realization of the full therapeutic potential of nucleic acids. Nanoscale nonviral vectors offer an attractive alternative to viral vectors as natural and synthetic polymers or polypeptides may be rationally designed to meet the unique demands of individual applications. A mechanistic understanding of cellular barriers is necessary to develop guidelines for designing custom gene carriers which are expected to greatly impact this delivery challenge. The work herein focused on the relationships among nanocomplex stability, intracellular trafficking and unpacking kinetics, and DNA degradation. Ultrasensitive nanosensors based on QD-FRET were developed to characterize the biophysical properties of nanocomplexes and study these rate-limiting steps. Quantitative image analysis enabled the distributions of the subpopulation of condensed or released DNA to be determined within the major cellular compartments encountered during gene transfer. The steady state stability and unpacking kinetics within these compartments were found to impact transgene expression, elucidating multiple design strategies to achieve efficient gene transfer. To address enzymatic barriers, a novel two-step QD-FRET nanosensor was developed to analyze unpacking and DNA degradation simultaneously, which has not been accomplished previously. Bioresponsive strategies such as disulfide crosslinking and thermosensitivity were evaluated by QD-FRET and quantitative compartmental analysis as case studies to determine appropriate design specifications for thiolated polymers and thermoresponsive polypeptides. Relevant nanobiophotonic tools were developed as a platform to study major rate-limiting barriers to nanomedicine and demonstrated the feasibility of using mechanistic information gained from these tools to guide the rational design of

  16. Radiation damage and rate limitations in tracking devices

    International Nuclear Information System (INIS)

    Gilchriese, M.G.D.

    1984-01-01

    In this note the author briefly discusses radiation damage to wire chambers and silicon strip devices and the electronics that may be associated with each of these. Scintillating fibers and CCD's are not discussed although the former appears to be a potentially radiation-resistant detector. In order to calculate radiation levels and rates the author assumed the following: an inelastic cross section of 100 mb at the SSC - six charged particles per unit of rapidity - photons and neutrons do not contribute to the background (photon conversions are negligible with a thin Be beam pipe) - beam gas interactions and beam losses (except during injection when I assume that the detector is ''off'') are negligible. This is discussed in a later section. - 1 Rad = 3.5 x 10 7 minimum ionizing particlescm 2

  17. Vesicular GABA Uptake Can Be Rate Limiting for Recovery of IPSCs from Synaptic Depression

    Directory of Open Access Journals (Sweden)

    Manami Yamashita

    2018-03-01

    Full Text Available Summary: Synaptic efficacy plays crucial roles in neuronal circuit operation and synaptic plasticity. Presynaptic determinants of synaptic efficacy are neurotransmitter content in synaptic vesicles and the number of vesicles undergoing exocytosis at a time. Bursts of presynaptic firings depress synaptic efficacy, mainly due to depletion of releasable vesicles, whereas recovery from strong depression is initiated by endocytic vesicle retrieval followed by refilling of vesicles with neurotransmitter. We washed out presynaptic cytosolic GABA to induce a rundown of IPSCs at cerebellar inhibitory cell pairs in slices from rats and then allowed fast recovery by elevating GABA concentration using photo-uncaging. The time course of this recovery coincided with that of IPSCs from activity-dependent depression induced by a train of high-frequency stimulation. We conclude that vesicular GABA uptake can be a limiting step for the recovery of inhibitory neurotransmission from synaptic depression. : Recovery of inhibitory synaptic transmission from activity-dependent depression requires refilling of vesicles with GABA. Yamashita et al. find that vesicular uptake rate of GABA is a slow process, limiting the recovery rate of IPSCs from depression.

  18. Energy policy implementation process : BC Hydro information session and workshop on stepped rates and access principles. draft ed.

    International Nuclear Information System (INIS)

    2003-01-01

    The government of British Columbia recognizes that some changes are needed in the energy sector to promote new investment and increase trade while maintaining low power rates and environmentally responsible energy development. BC Hydro held a workshop where several rate design parameters were presented in accordance with the Energy Plan objectives. The workshop identified some key implementation measures and invited input from customers. This paper describes 8 policy actions that will be implemented, or which are already underway to achieve objectives of the Energy Plan. Policy Action number 14 states that under the new rate structures, large electricity consumers will be able to choose a supplier other than the local distributor. Policy Action number 21 states that new rate structures will offer better price signals to large electricity consumers for conservation and energy efficiency. A new stepped rate has been proposed to implement the policy actions. The stepped rate design features different rates for different blocks of energy consumption. The stepped rate design encourages customers to invest in cost-effective conservation and self generation. The disadvantage is that customers shut down facilities and receive financial benefits as if they had invested in conservation. Customers will also continually switch back and forth between rate designs or suppliers, depending on which one provides immediate gains. It was noted that a stepped rate design requires a choice of where to place the cutoff between various Tier rates. Market options for calculating Tier 1 and Tier 2 rates were described. The three causes for reductions in energy consumption were identified as being energy efficiency, self generation, and partial or full shutdown. 4 tabs., 10 figs

  19. Limitation of leakage rate measurement sensitivity; Limitation de la sensibilite des mesures de debit de fuite

    Energy Technology Data Exchange (ETDEWEB)

    Paigne, Jacques [Commissariat a l' energie atomique et aux energies alternatives - CEA, Services de Physique Appliquee (France)

    1964-08-15

    This note reports an experimental study which aimed at determining to which extent an enclosure degassing could affect the sensitivity of a helium detection cell because of an increased background noise. The author first describes the measurement method and the helium partial pressure measurement method. He then reports an application to leakage rate measurements, and discusses the influence of background noise (influence of degassing, and influence of atmospheric air)

  20. Attaining the rate-independent limit of a rate-dependent strain gradient plasticity theory

    DEFF Research Database (Denmark)

    El-Naaman, Salim Abdallah; Nielsen, Kim Lau; Niordson, Christian Frithiof

    2016-01-01

    The existence of characteristic strain rates in rate-dependent material models, corresponding to rate-independent model behavior, is studied within a back stress based rate-dependent higher order strain gradient crystal plasticity model. Such characteristic rates have recently been observed...... for steady-state processes, and the present study aims to demonstrate that the observations in fact unearth a more widespread phenomenon. In this work, two newly proposed back stress formulations are adopted to account for the strain gradient effects in the single slip simple shear case, and characteristic...... rates for a selected quantity are identified through numerical analysis. Evidently, the concept of a characteristic rate, within the rate-dependent material models, may help unlock an otherwise inaccessible parameter space....

  1. The reaction rate for dissociative adsorption of N-2 on stepped Ru(0001): Six-dimensional quantum calculations

    DEFF Research Database (Denmark)

    van Harrevelt, Rob; Honkala, Johanna Karoliina; Nørskov, Jens Kehlet

    2005-01-01

    Quantum-mechanical calculations of the reaction rate for dissociative adsorption of N-2 on stepped Ru(0001) are presented. Converged six-dimensional quantum calculations for this heavy-atom reaction have been performed using the multiconfiguration time-dependent Hartree method. A potential...

  2. The correlates of body composition with heart rate recovery after step test: an exploratory study of Malaysian adolescents.

    Directory of Open Access Journals (Sweden)

    Redzal Abu Hanifah

    Full Text Available In adults, heart rate recovery is a predictor of mortality, while in adolescents it is associated with cardio-metabolic risk factors. The aim of this study was to examine the relationship between body composition measures and heart rate recovery (HRR after step test in Malaysian secondary school students.In the Malaysian Health and Adolescents Longitudinal Research Team (MyHEART study, 1071 healthy secondary school students, aged 13 years old, participated in the step test. Parameters for body composition measures were body mass index z-score, body fat percentage, waist circumference, and waist height ratio. The step test was conducted by using a modified Harvard step test. Heart rate recovery of 1 minute (HRR1min and heart rate recovery of 2 minutes (HRR2min were calculated by the difference between the peak pulse rate during exercise and the resting pulse rate at 1 and 2 minutes, respectively. Analysis was done separately based on gender. Pearson correlation analysis was used to determine the association between the HRR parameters with body composition measures, while multiple regression analysis was used to determine which body composition measures was the strongest predictor for HRR.For both gender groups, all body composition measures were inversely correlated with HRR1min. In girls, all body composition measures were inversely correlated with HRR2min, while in boys all body composition measures, except BMI z-score, were associated with HRR2min. In multiple regression, only waist circumference was inversely associated with HRR2min (p=0.024 in boys, while in girls it was body fat percentage for HRR2min (p=0.008.There was an inverse association between body composition measurements and HRR among apparently healthy adolescents. Therefore, it is important to identify cardio-metabolic risk factors in adolescent as an early prevention of consequent adulthood morbidity. This reiterates the importance of healthy living which should start from young.

  3. The Correlates of Body Composition with Heart Rate Recovery after Step Test: An Exploratory Study of Malaysian Adolescents

    Science.gov (United States)

    Abu Hanifah, Redzal; Mohamed, Mohd. Nahar Azmi; Jaafar, Zulkarnain; Abdul Mohsein, Nabilla Al-Sadat; Jalaludin, Muhammad Yazid; Abdul Majid, Hazreen; Murray, Liam; Cantwell, Marie; Su, Tin Tin

    2013-01-01

    Background In adults, heart rate recovery is a predictor of mortality, while in adolescents it is associated with cardio-metabolic risk factors. The aim of this study was to examine the relationship between body composition measures and heart rate recovery (HRR) after step test in Malaysian secondary school students. Methods In the Malaysian Health and Adolescents Longitudinal Research Team (MyHEART) study, 1071 healthy secondary school students, aged 13 years old, participated in the step test. Parameters for body composition measures were body mass index z-score, body fat percentage, waist circumference, and waist height ratio. The step test was conducted by using a modified Harvard step test. Heart rate recovery of 1 minute (HRR1min) and heart rate recovery of 2 minutes (HRR2min) were calculated by the difference between the peak pulse rate during exercise and the resting pulse rate at 1 and 2 minutes, respectively. Analysis was done separately based on gender. Pearson correlation analysis was used to determine the association between the HRR parameters with body composition measures, while multiple regression analysis was used to determine which body composition measures was the strongest predictor for HRR. Results For both gender groups, all body composition measures were inversely correlated with HRR1min. In girls, all body composition measures were inversely correlated with HRR2min, while in boys all body composition measures, except BMI z-score, were associated with HRR2min. In multiple regression, only waist circumference was inversely associated with HRR2min (p=0.024) in boys, while in girls it was body fat percentage for HRR2min (p=0.008). Conclusion There was an inverse association between body composition measurements and HRR among apparently healthy adolescents. Therefore, it is important to identify cardio-metabolic risk factors in adolescent as an early prevention of consequent adulthood morbidity. This reiterates the importance of healthy living

  4. Path analysis suggests phytoene accumulation is the key step limiting the carotenoid pathway in white carrot roots

    Directory of Open Access Journals (Sweden)

    Carlos Antonio Fernandes Santos

    2005-01-01

    Full Text Available Two F2 carrot (Daucus carota L. populations (orange rooted Brasilia x very dark orange rooted High Carotene Mass - HCM cross and the dark orange rooted cultivated variety B493 x white rooted wild carrot Queen Anne's Lace - QAL cross with very unrelated genetic backgrounds were used to investigate intrinsic factors limiting carotenoid accumulation in carrots by applying phenotypic correlation and path analysis to study the relationships between major root carotenes, root color and several other morphological traits. Most of the correlations between traits were close and agreed in sign between the two populations. Root weight had a moderate to highly significant positive correlation with leaf length, root length and top and middle root diameter. Although phenotypic correlations failed to identify the order of the substrates and products in the carotenoid pathway the correct order of substrates and products (phytoene -> zeta-carotene -> lycopene was identified in the causal diagram of beta-carotene for the Brasilia x HCM population. Path analysis of beta-carotene synthesis in the B493 x QAL population suggested that selection for root carotenes had little effect on plant morphological traits. Causal model of beta-carotene and lycopene in the B493 x QAL population suggested that phytoene synthesis is the key step limiting the carotenoid pathway in white carrots. Path analysis, first presented by Sewall Wright to study quantitative traits, appears to be a powerful statistical approach for the identification of key compounds in complex pathways.

  5. Blastocyst utilization rates after continuous culture in two commercial single-step media: a prospective randomized study with sibling oocytes.

    Science.gov (United States)

    Sfontouris, Ioannis A; Kolibianakis, Efstratios M; Lainas, George T; Venetis, Christos A; Petsas, George K; Tarlatzis, Basil C; Lainas, Tryfon G

    2017-10-01

    The aim of this study is to determine whether blastocyst utilization rates are different after continuous culture in two different commercial single-step media. This is a paired randomized controlled trial with sibling oocytes conducted in infertility patients, aged ≤40 years with ≥10 oocytes retrieved assigned to blastocyst culture and transfer. Retrieved oocytes were randomly allocated to continuous culture in either Sage one-step medium (Origio) or Continuous Single Culture (CSC) medium (Irvine Scientific) without medium renewal up to day 5 post oocyte retrieval. Main outcome measure was the proportion of embryos suitable for clinical use (utilization rate). A total of 502 oocytes from 33 women were randomly allocated to continuous culture in either Sage one-step medium (n = 250) or CSC medium (n = 252). Fertilization was performed by either in vitro fertilization or intracytoplasmic sperm injection, and embryo transfers were performed on day 5. Two patients had all blastocysts frozen due to the occurrence of severe ovarian hyperstimulation syndrome. Fertilization and cleavage rates, as well as embryo quality on day 3, were similar in the two media. Blastocyst utilization rates (%, 95% CI) [55.4% (46.4-64.1) vs 54.7% (44.9-64.6), p = 0.717], blastocyst formation rates [53.6% (44.6-62.5) vs 51.9 (42.2-61.6), p = 0.755], and proportion of good quality blastocysts [36.8% (28.1-45.4) vs 36.1% (27.2-45.0), p = 0.850] were similar in Sage one-step and CSC media, respectively. Continuous culture of embryos in Sage one-step and CSC media is associated with similar blastocyst development and utilization rates. Both single-step media appear to provide adequate support during in vitro preimplantation embryo development. Whether these observations are also valid for other continuous single medium protocols remains to be determined. NCT02302638.

  6. Correction to the count-rate detection limit and sample/blank time-allocation methods

    International Nuclear Information System (INIS)

    Alvarez, Joseph L.

    2013-01-01

    A common form of count-rate detection limits contains a propagation of uncertainty error. This error originated in methods to minimize uncertainty in the subtraction of the blank counts from the gross sample counts by allocation of blank and sample counting times. Correct uncertainty propagation showed that the time allocation equations have no solution. This publication presents the correct form of count-rate detection limits. -- Highlights: •The paper demonstrated a proper method of propagating uncertainty of count rate differences. •The standard count-rate detection limits were in error. •Count-time allocation methods for minimum uncertainty were in error. •The paper presented the correct form of the count-rate detection limit. •The paper discussed the confusion between count-rate uncertainty and count uncertainty

  7. Two-step rating-based 'double-faced applicability' test for sensory analysis of spread products as an alternative to descriptive analysis with trained panel.

    Science.gov (United States)

    Kim, In-Ah; den-Hollander, Elyn; Lee, Hye-Seong

    2018-03-01

    Descriptive analysis with a trained sensory panel has thus far been the most well defined methodology to characterize various products. However, in practical terms, intensive training in descriptive analysis has been recognized as a serious defect. To overcome this limitation, various novel rapid sensory profiling methodologies have been suggested in the literature. Among these, attribute-based methodologies such as check-all-that-apply (CATA) questions showed results comparable to those of conventional sensory descriptive analysis. Kim, Hopkinson, van Hout, and Lee (2017a, 2017b) have proposed a novel attribute-based methodology termed the two-step rating-based 'double-faced applicability' test with a novel output measure of applicability magnitude (d' A ) for measuring consumers' product usage experience throughout various product usage stages. In this paper, the potential of the two-step rating-based 'double-faced applicability' test with d' A was investigated as an alternative to conventional sensory descriptive analysis in terms of sensory characterization and product discrimination. Twelve commercial spread products were evaluated using both conventional sensory descriptive analysis with a trained sensory panel and two-step rating-based 'double-faced applicability' test with an untrained sensory panel. The results demonstrated that the 'double-faced applicability' test can be used to provide a direct measure of the applicability magnitude of sensory attributes of the samples tested in terms of d' A for sensory characterization of individual samples and multiple sample comparisons. This suggests that when the appropriate list of attributes to be used in the questionnaire is already available, the two-step rating-based 'double-faced applicability' test with d' A can be used as a more efficient alternative to conventional descriptive analysis, without requiring any intensive training process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. 14 CFR 399.41 - Zones of limited suspension for international cargo rates.

    Science.gov (United States)

    2010-01-01

    ... TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS STATEMENTS OF GENERAL POLICY Policies Relating to Rates and Tariffs § 399.41 Zones of limited suspension for international cargo rates. (a) Applicability. This section states the Board's policy for suspending rate changes for the transportation of property...

  9. Cardiorespiratory endurance evaluation using heart rate analysis during ski simulator exercise and the Harvard step test in elementary school students.

    Science.gov (United States)

    Lee, Hyo Taek; Roh, Hyo Lyun; Kim, Yoon Sang

    2016-01-01

    [Purpose] Efficient management using exercise programs with various benefits should be provided by educational institutions for children in their growth phase. We analyzed the heart rates of children during ski simulator exercise and the Harvard step test to evaluate the cardiopulmonary endurance by calculating their post-exercise recovery rate. [Subjects and Methods] The subjects (n = 77) were categorized into a normal weight and an overweight/obesity group by body mass index. They performed each exercise for 3 minutes. The cardiorespiratory endurance was calculated using the Physical Efficiency Index formula. [Results] The ski simulator and Harvard step test showed that there was a significant difference in the heart rates of the 2 body mass index-based groups at each minute. The normal weight and the ski-simulator group had higher Physical Efficiency Index levels. [Conclusion] This study showed that a simulator exercise can produce a cumulative load even when performed at low intensity, and can be effectively utilized as exercise equipment since it resulted in higher Physical Efficiency Index levels than the Harvard step test. If schools can increase sport durability by stimulating students' interests, the ski simulator exercise can be used in programs designed to improve and strengthen students' physical fitness.

  10. Cool-down flow-rate limits imposed by thermal stresses in LNG pipelines

    Science.gov (United States)

    Novak, J. K.; Edeskuty, F. J.; Bartlit, J. R.

    Warm cryogenic pipelines are usually cooled to operating temperature by a small, steady flow of the liquid cryogen. If this flow rate is too high or too low, undesirable stresses will be produced. Low flow-rate limits based on avoidance of stratified two-phase flow were calculated for pipelines cooled with liquid hydrogen or nitrogen. High flow-rate limits for stainless steel and aluminum pipelines cooled by liquid hydrogen or nitrogen were determined by calculating thermal stress in thick components vs flow rate and then selecting some reasonable stress limits. The present work extends these calculations to pipelines made of AISI 304 stainless steel, 6061 aluminum, or ASTM A420 9% nickel steel cooled by liquid methane or a typical natural gas. Results indicate that aluminum and 9% nickel steel components can tolerate very high cool-down flow rates, based on not exceeding the material yield strength.

  11. High-Pressure Limit Rate Rules for α-H Isomerization of Hydroperoxyalkylperoxy Radicals

    KAUST Repository

    Mohamed, Samah Y; Davis, Alexander Cory; Al Rashidi, Mariam J; Sarathy, Mani

    2018-01-01

    group. In this work, a combination of high level composite methods - CBS-QB3, G3 and G4 - is used to determine the high-pressure-limit rate parameters for the title reaction. Rate rules for H-migration reactions proceeding through 5-, 6-, 7- and 8

  12. Two-step carbon coating of lithium vanadium phosphate as high-rate cathode for lithium-ion batteries

    Science.gov (United States)

    Kuang, Quan; Zhao, Yanming

    2012-10-01

    Carbon-coated Li3V2(PO4)3 was firstly prepared at 850 °C via two-step reaction method combined sol-gel and conventional solid-state synthesis by using VPO4/carbon as an intermediate. Two different carbon sources, citric acid and glucose as carbon additives in sequence, ultimately deduced double carbon-coated Li3V2(PO4)3 as a high-rate cathode material. The Li3V2(PO4)3/carbon with 4.39% residual carbon has a splendid electronic conductivity of 4.76×10-2 S cm-1. Even in the voltage window of 2.5-4.8 V, the Li3V2(PO4)3/carbon cathode can retain outstanding rate ability (170.4 mAh g-1 at 1.2 C, 101.9 mAh g-1 at 17 C), and no degradation is found after 120 C current rate. These phenomena show that the two-step carbon-coated Li3V2(PO4)3 can act as a fast charge-discharge cathode material for high-power Li-ion batteries. Furthermore, it's believed that this synthesize method can be easily transplanted to prepare other lithiated vanadium-based phosphates.

  13. Mass-transport limitation to in-cloud reaction rates: Implications of new accommodation coefficient measurements

    International Nuclear Information System (INIS)

    Schwartz, S.E.

    1988-10-01

    Although it has been recognized for some time that the rate of reactive uptake of gases in cloudwater can depend on the value of the mass-accommodation coefficient (α) describing interfacial mass transport (MT), definitive evaluation of such rates is only now becoming possible with the availability of measurements of α for gases of atmospheric interest at air-water interfaces. Examination of MT limitation to the rate of in-cloud aqueous-phase oxidation of SO 2 by O 3 and H 2 O 2 shows that despite the low value of α/sub O3/ (5 /times/ 10/sup /minus/4/), interfacial MT of this species is not limiting under essentially all conditions of interest; the high values of α for SO 2 (≥ 0.2) and H 2 O 2 (≥ 0.08) indicate no interfacial MT limitation for these species also. Although gas- and aqueous-phase MT can be limiting under certain extremes of conditions, treating the system as under chemical kinetic control is generally an excellent approximation. Interfacial MT limitation also is found not to hinder the rate of H 2 O 2 formation by aqueous-phase disproportionation of HO 2 . Finally, the rapid uptake of N 2 O 5 by cloud droplets implies that the yield of aqueous HNO 3 from in-cloud gas-phase oxidation of NO 2 by O 3 can be substantial even under daytime conditions. This report consists of copies of viewgraphs prepared for this presentation

  14. New limit on rate of 2ν ββ decay of 136Xe

    International Nuclear Information System (INIS)

    Kuzminov, V.V.; Lobashev, V.M.; Novikov, V.M.; Ovchinnikov, B.M.; Pomansky, A.A.; Pritychenko, B.V.

    1991-01-01

    A significant background suppression was achieved in a new step of measurements in the Baksan underground laboratory 136 Xe ββ experiment, using a high-pressure gridded ionization chamber. In order to reduce outer γ-ray background, the chamber was placed inside the passive shielding consisting of 15 cm of lead and of 10 cm of copper. Half-life limit of 2.7x10 20 yrs is obtained for 2ν ββ mode of 136 Xe. (R.P.) 12 refs., 2 figs

  15. Glucose phosphorylation is not rate limiting for accumulation of glycogen from glucose in perfused livers from fasted rats

    International Nuclear Information System (INIS)

    Youn, J.H.; Ader, M.; Bergman, R.N.

    1989-01-01

    Incorporation of Glc and Fru into glycogen was measured in perfused livers from 24-h fasted rats using [6-3H]Glc and [U-14C]Fru. For the initial 20 min, livers were perfused with low Glc (2 mM) to deplete hepatic glycogen and were perfused for the following 30 min with various combinations of Glc and Fru. With constant Fru (2 mM), increasing perfusate Glc increased the relative contribution of Glc carbons to glycogen (7.2 +/- 0.4, 34.9 +/- 2.8, and 59.1 +/- 2.7% at 2, 10, and 20 mM Glc, respectively; n = 5 for each). During perfusion with substrate levels seen during refeeding (10 mM Glc, 1.8 mumol/g/min gluconeogenic flux from 2 mM Fru), Fru provided 54.7 +/- 2.7% of the carbons for glycogen, while Glc provided only 34.9 +/- 2.8%, consistent with in vivo estimations. However, the estimated rate of Glc phosphorylation was at least 1.10 +/- 0.11 mumol/g/min, which exceeded by at least 4-fold the glycogen accumulation rate (0.28 +/- 0.04 mumol of glucose/g/min). The total rate of glucose 6-phosphate supply via Glc phosphorylation and gluconeogenesis (2.9 mumol/g/min) exceeded reported in vivo rates of glycogen accumulation during refeeding. Thus, in perfused livers of 24-h fasted rats there is an apparent redundancy in glucose 6-phosphate supply. These results suggest that the rate-limiting step for hepatic glycogen accumulation during refeeding is located between glucose 6-phosphate and glycogen, rather than at the step of Glc phosphorylation or in the gluconeogenic pathway

  16. Effect of PbI2 deposition rate on two-step PVD/CVD all-vacuum prepared perovskite

    International Nuclear Information System (INIS)

    Ioakeimidis, Apostolos; Christodoulou, Christos; Lux-Steiner, Martha; Fostiropoulos, Konstantinos

    2016-01-01

    In this work we fabricate all-vacuum processed methyl ammonium lead halide perovskite by a sequence of physical vapour deposition of PbI 2 and chemical vapour deposition (CVD) of CH 3 NH 3 I under a static atmosphere. We demonstrate that for higher deposition rate the (001) planes of PbI 2 film show a higher degree of alignment parallel to the sample's surface. From X-ray diffraction data of the resulted perovskite film we derive that the intercalation rate of CH 3 NH 3 I is fostered for PbI 2 films with higher degree of (001) planes alignment. The stoichiometry of the produced perovskite film is also studied by Hard X-ray photoelectron spectroscopy measurements. Complete all-vacuum perovskite solar cells were fabricated on glass/ITO substrates coated by an ultra-thin (5 nm) Zn-phthalocyanine film as hole selective layer. A dependence of residual PbI 2 on the solar cells performance is displayed, while photovoltaic devices with efficiency up to η=11.6% were achieved. - Graphical abstract: A two-step PVD/CVD processed perovskite film with the CVD intercalation rate of CH 3 NCH 3 molecules been fostered by increasing the PVD rate of PbI 2 and prolonging the CVD time. - Highlights: • A simple PVD/CVD process for perovskite film production. • Increased PVD rate yields better alignment of the PbI 2 (001) crystallite planes. • CH 3 NH 3 I intercalation process fostered by increased PbI 2 PVD rate. • Stoichiometric CH 3 NH 3 PbI 3 suitable as absorber in photovoltaic applications • Reduced PbI 2 residue at the bottom of CH 3 NH 3 PbI 3 improves device performance.

  17. An efficient single-step scheme for manipulating quantum information of two trapped ions beyond the Lamb-Dicke limit

    International Nuclear Information System (INIS)

    Wei, L.F.; Nori, Franco

    2003-01-01

    Based on the exact conditional quantum dynamics for a two-ion system, we propose an efficient single-step scheme for coherently manipulating quantum information of two trapped cold ions by using a pair of synchronous laser pulses. Neither the auxiliary atomic level nor the Lamb-Dicke approximation are needed

  18. Success rate evaluation of clinical governance implementation in teaching hospitals in Kerman (Iran) based on nine steps of Karsh's model.

    Science.gov (United States)

    Vali, Leila; Mastaneh, Zahra; Mouseli, Ali; Kardanmoghadam, Vida; Kamali, Sodabeh

    2017-07-01

    One of the ways to improve the quality of services in the health system is through clinical governance. This method aims to create a framework for clinical services providers to be accountable in return for continuing improvement of quality and maintaining standards of services. To evaluate the success rate of clinical governance implementation in Kerman teaching hospitals based on 9 steps of Karsh's Model. This cross-sectional study was conducted in 2015 on 94 people including chief executive officers (CEOs), nursing managers, clinical governance managers and experts, head nurses and nurses. The required data were collected through a researcher-made questionnaire containing 38 questions with three-point Likert Scale (good, moderate, and weak). The Karsh's Model consists of nine steps including top management commitment to change, accountability for change, creating a structured approach for change, training, pilot implementation, communication, feedback, simulation, and end-user participation. Data analysis using descriptive statistics and Mann-Whitney-Wilcoxon test was done by SPSS software version 16. About 81.9 % of respondents were female and 74.5 have a Bachelor of Nursing (BN) degree. In general, the status of clinical governance implementation in studied hospitals based on 9 steps of the model was 44 % (moderate). A significant relationship was observed among accountability and organizational position (p=0.0012) and field of study (p=0.000). Also, there were significant relationships between structure-based approach and organizational position (p=0.007), communication and demographic characteristics (p=0.000), and end-user participation with organizational position (p=0.03). Clinical governance should be implemented by correct needs assessment and participation of all stakeholders, to ensure its enforcement in practice, and to enhance the quality of services.

  19. On the rate determining step in fission gas release from high burn-up water reactor fuel during power transients

    International Nuclear Information System (INIS)

    Walker, C.T.; Mogensen, M.

    1987-01-01

    The radial distribution of grain boundary gas in a PWR and a BWR fuel is reported. The measurements were made using a new approach involving X-ray fluorescence analysis and electron probe microanalysis. In both fuels the concentration of grain boundary gas was much higher than hitherto suspected. The gas was mainly contained in the bubble/pore structure. The factors that determined the fraction of gas released from the grains and the level of gas retention on the grain boundaries are identified and discussed. The variables involved are the local fuel stoichiometry, the amount of open porosity, the magnitude of the local compressive hydrostatic stress and the interaction of metallic precipitates with gas bubbles on the grain faces. It is concluded that under transient conditions the interlinkage of gas bubbles on the grain faces and the subsequent formation of grain edge tunnels is the rate determining step for gas release; at least when high burn-up fuel is involved. (orig.)

  20. Limits to preference and the sensitivity of choice to rate and amount of food.

    Science.gov (United States)

    Aparicio, Carlos F; Baum, William M; Hughes, Christine E; Pitts, Raymond C

    2016-03-01

    Studies of choice holding food-amount ratio constant while varying food-rate ratio within sessions showed that local changes in preference depend on relative amount of food. The present study investigated whether sensitivity of choice to food-rate ratio and sensitivity to food-amount ratio are independent of one another when food-rate ratios are varied across sessions and food-amount ratios are varied within sessions. Food deliveries for rats' presses on the left and right levers were scheduled according to three different food-rate ratios of 1:1, 9:1, and 1:9; each food-rate ratio lasted for 106 sessions and was arranged independently of seven food-amount ratios (7:1, 6:2, 5:3, 4:4, 3:5, 2:6, and 1:7 food pellets) occurring within sessions in random sequence. Each amount ratio lasted for 10 food deliveries and was separated from another by a 60-s blackout. Sensitivity to rate ratio was high (1.0) across food deliveries. Sensitivity to amount ratio was low when food rates were equal across alternatives, but was high when rate ratio and amount ratio opposed one another. When rate ratio and amount ratio went in the same direction, choice ratio reached an elevenfold limit which reduced sensitivity to approximately zero. We conclude that three factors affect sensitivity to amount: (1) the limit to preference, (2) the equal effect on preference of amounts greater than four pellets, and (3) the absence of differential effects of switches in amount in the equal-rates (1:1) condition. Taken together, these findings indicate that rate and amount only sometimes combine independently as additive variables to determine preference when amount ratios vary frequently within sessions. © 2016 Society for the Experimental Analysis of Behavior.

  1. Packetized Predictive Control for Rate-Limited Networks via Sparse Representation

    DEFF Research Database (Denmark)

    Nagahara, Masaaki; Quevedo, Daniel; Østergaard, Jan

    2012-01-01

    controller and the plant input. To achieve robustness with respect to dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. In our formulation, we design sparse packets for rate-limited networks, by adopting an an ℓ0 optimization...

  2. On the rate of triplet excitation transfer in the diffuse limit

    International Nuclear Information System (INIS)

    Davidovich, M.A.; Knox, R.S.

    1979-11-01

    The usefulness of spectral data in estimating intermolecular triplet excitation transfer rates in found to be rather limited and to depend explicitly on the mechaisms which allow the optical transitions. Necessary conditions for the validity of such use of spectra are given, and the otherwise required correction factors are discussed and estimated. (Author) [pt

  3. Maximum heart rate in brown trout (Salmo trutta fario) is not limited by firing rate of pacemaker cells.

    Science.gov (United States)

    Haverinen, Jaakko; Abramochkin, Denis V; Kamkin, Andre; Vornanen, Matti

    2017-02-01

    Temperature-induced changes in cardiac output (Q̇) in fish are largely dependent on thermal modulation of heart rate (f H ), and at high temperatures Q̇ collapses due to heat-dependent depression of f H This study tests the hypothesis that firing rate of sinoatrial pacemaker cells sets the upper thermal limit of f H in vivo. To this end, temperature dependence of action potential (AP) frequency of enzymatically isolated pacemaker cells (pacemaker rate, f PM ), spontaneous beating rate of isolated sinoatrial preparations (f SA ), and in vivo f H of the cold-acclimated (4°C) brown trout (Salmo trutta fario) were compared under acute thermal challenges. With rising temperature, f PM steadily increased because of the acceleration of diastolic depolarization and shortening of AP duration up to the break point temperature (T BP ) of 24.0 ± 0.37°C, at which point the electrical activity abruptly ceased. The maximum f PM at T BP was much higher [193 ± 21.0 beats per minute (bpm)] than the peak f SA (94.3 ± 6.0 bpm at 24.1°C) or peak f H (76.7 ± 2.4 at 15.7 ± 0.82°C) (P brown trout in vivo. Copyright © 2017 the American Physiological Society.

  4. Three-step approach for prediction of limit cycle pressure oscillations in combustion chambers of gas turbines

    Science.gov (United States)

    Iurashev, Dmytro; Campa, Giovanni; Anisimov, Vyacheslav V.; Cosatto, Ezio

    2017-11-01

    Currently, gas turbine manufacturers frequently face the problem of strong acoustic combustion driven oscillations inside combustion chambers. These combustion instabilities can cause extensive wear and sometimes even catastrophic damages to combustion hardware. This requires prevention of combustion instabilities, which, in turn, requires reliable and fast predictive tools. This work presents a three-step method to find stability margins within which gas turbines can be operated without going into self-excited pressure oscillations. As a first step, a set of unsteady Reynolds-averaged Navier-Stokes simulations with the Flame Speed Closure (FSC) model implemented in the OpenFOAM® environment are performed to obtain the flame describing function of the combustor set-up. The standard FSC model is extended in this work to take into account the combined effect of strain and heat losses on the flame. As a second step, a linear three-time-lag-distributed model for a perfectly premixed swirl-stabilized flame is extended to the nonlinear regime. The factors causing changes in the model parameters when applying high-amplitude velocity perturbations are analysed. As a third step, time-domain simulations employing a low-order network model implemented in Simulink® are performed. In this work, the proposed method is applied to a laboratory test rig. The proposed method permits not only the unsteady frequencies of acoustic oscillations to be computed, but the amplitudes of such oscillations as well. Knowing the amplitudes of unstable pressure oscillations, it is possible to determine how these oscillations are harmful to the combustor equipment. The proposed method has a low cost because it does not require any license for computational fluid dynamics software.

  5. Effective reaction rates in diffusion-limited phosphorylation-dephosphorylation cycles

    Science.gov (United States)

    Szymańska, Paulina; Kochańczyk, Marek; Miekisz, Jacek; Lipniacki, Tomasz

    2015-02-01

    We investigate the kinetics of the ubiquitous phosphorylation-dephosphorylation cycle on biological membranes by means of kinetic Monte Carlo simulations on the triangular lattice. We establish the dependence of effective macroscopic reaction rate coefficients as well as the steady-state phosphorylated substrate fraction on the diffusion coefficient and concentrations of opposing enzymes: kinases and phosphatases. In the limits of zero and infinite diffusion, the numerical results agree with analytical predictions; these two limits give the lower and the upper bound for the macroscopic rate coefficients, respectively. In the zero-diffusion limit, which is important in the analysis of dense systems, phosphorylation and dephosphorylation reactions can convert only these substrates which remain in contact with opposing enzymes. In the most studied regime of nonzero but small diffusion, a contribution linearly proportional to the diffusion coefficient appears in the reaction rate. In this regime, the presence of opposing enzymes creates inhomogeneities in the (de)phosphorylated substrate distributions: The spatial correlation function shows that enzymes are surrounded by clouds of converted substrates. This effect becomes important at low enzyme concentrations, substantially lowering effective reaction rates. Effective reaction rates decrease with decreasing diffusion and this dependence is more pronounced for the less-abundant enzyme. Consequently, the steady-state fraction of phosphorylated substrates can increase or decrease with diffusion, depending on relative concentrations of both enzymes. Additionally, steady states are controlled by molecular crowders which, mostly by lowering the effective diffusion of reactants, favor the more abundant enzyme.

  6. Charge-exchange wall physical erosion rates for a proposed INTOR/FED limiter

    International Nuclear Information System (INIS)

    Heifetz, D.; Schmidt, J.; Ulrickson, M.; Post, D.

    1983-01-01

    We have analyzed power deposition and physical erosion rates on the first wall and limiter due to charge-exchange neutrals in a proposed pump limiter design for the INTOR/FED tokamak. Plasma conditions were modeled using the one-dimensional plasma transport code baldur. Neutral transport was modeled using a two-dimensional, multispecies Monte Carlo algorithm. No chemical erosion or wall redeposition processes were included. Two possible plasma discharges with different edge densities and temperatures were modeled, a regime with T/sub e/ approx.300 eV and napprox.5 x 10 12 cm - 3 , and a hotter, less dense edge regime produced with pellet fueling. We found that the erosion of the stainless steel vacuum vessel wall was highly localized in each case to the two points just beyond the limiter tips, and to the point directly across from the neutralizer plate, with peak erosion rates approx.2 cm/yr, assuming a 40% duty cycle. The erosion of a carbon limiter, neglecting redeposition and chemical erosion, varied in the two cases from 1.6--4 cm/yr, for the same duty cycle. The hotter, less dense discharge produced less sputtering. However achieving truly tolerable physical sputtering rates may require a very low edge temperature, plasma

  7. One-step electrochemically expanded graphite foil for flexible all-solid supercapacitor with high rate performance

    International Nuclear Information System (INIS)

    Li, Han-Yu; Yu, Yao; Liu, Lang; Liu, Lin; Wu, Yue

    2017-01-01

    Flexible solid-state supercapacitors (SSCs) as a candidate for energy storage source, have been attracting intensive attention. Graphene-based materials for SSCs have been widely studied. However, most reported preparation methods for graphene-based materials are energy-consuming, time-consuming and environmentally hazardous, what’s more, the assembling of SSCs need additives, such as current collectors, flexible substrates. So, it is necessary to develop simpler and greener attempts to achieve high-performance, cost-effective, substrates/additives-free and flexible electrodes for SSC devices. Herein, we reported a green and facile one-step process of electrochemical oxidation and expansion in salt solution to activate graphite foil (GF) for fabricating expanded graphite foil (EGF). The EGF electrode with unique structure and high conductivity showed high supercapacitor performance of 65 mF cm −2 , remarkable rate-capability maintaining at a level of 80% even at a current density of 20 mA cm −2 and excellent cycling stability with ∼95% capacitance remaining after 10000 cycles at a current density of 20 mA cm −2 . Moreover, a symmetric flexible all-solid supercapacitor (SSC) device was integrated using EGFs without any current collectors and additives. The flexible EGF-based device showed a high capacitance capacity of 30.5 mF cm −2 , excellent rate performance and good cycle stability which make it holds promise for applications in flexible, portable and wearable electronic devices.

  8. Simple scaling laws for the evaporation of droplets pinned on pillars: Transfer-rate- and diffusion-limited regimes.

    Science.gov (United States)

    Hernandez-Perez, Ruth; García-Cordero, José L; Escobar, Juan V

    2017-12-01

    The evaporation of droplets can give rise to a wide range of interesting phenomena in which the dynamics of the evaporation are crucial. In this work, we find simple scaling laws for the evaporation dynamics of axisymmetric droplets pinned on millimeter-sized pillars. Different laws are found depending on whether evaporation is limited by the diffusion of vapor molecules or by the transfer rate across the liquid-vapor interface. For the diffusion-limited regime, we find that a mass-loss rate equal to 3/7 of that of a free-standing evaporating droplet brings a good balance between simplicity and physical correctness. We also find a scaling law for the evaporation of multicomponent solutions. The scaling laws found are validated against experiments of the evaporation of droplets of (1) water, (2) blood plasma, and (3) a mixture of water and polyethylene glycol, pinned on acrylic pillars of different diameters. These results shed light on the macroscopic dynamics of evaporation on pillars as a first step towards the understanding of other complex phenomena that may be taking place during the evaporation process, such as particle transport and chemical reactions.

  9. Simple scaling laws for the evaporation of droplets pinned on pillars: Transfer-rate- and diffusion-limited regimes

    Science.gov (United States)

    Hernandez-Perez, Ruth; García-Cordero, José L.; Escobar, Juan V.

    2017-12-01

    The evaporation of droplets can give rise to a wide range of interesting phenomena in which the dynamics of the evaporation are crucial. In this work, we find simple scaling laws for the evaporation dynamics of axisymmetric droplets pinned on millimeter-sized pillars. Different laws are found depending on whether evaporation is limited by the diffusion of vapor molecules or by the transfer rate across the liquid-vapor interface. For the diffusion-limited regime, we find that a mass-loss rate equal to 3/7 of that of a free-standing evaporating droplet brings a good balance between simplicity and physical correctness. We also find a scaling law for the evaporation of multicomponent solutions. The scaling laws found are validated against experiments of the evaporation of droplets of (1) water, (2) blood plasma, and (3) a mixture of water and polyethylene glycol, pinned on acrylic pillars of different diameters. These results shed light on the macroscopic dynamics of evaporation on pillars as a first step towards the understanding of other complex phenomena that may be taking place during the evaporation process, such as particle transport and chemical reactions.

  10. Study on the limiting acceleration rate in the VLEPP linear accelerator

    International Nuclear Information System (INIS)

    Balakin, V.E.; Brezhnev, O.N.; Zakhvatkin, M.N.

    1987-01-01

    To realize the design of colliding linear electron-positron beams it is necessary to solve the radical problem of production of accelerating structure with acceleration rate of approximately 100 MeV/m which can accelerate 10 12 particles in a bunch. Results of experimental studies of the limiting acceleration rate in the VLEPP accelerating structure are presented. Accelerating sections of different length were tested. When testing sections 29 cm long the acceleration rate of 55 MeV/m was attained, and for 1 m section the value reached 40 MeV/m. The maximum rate of acceleration (90 MeV/m) was attained when electric field intensity on the structure surface constituted more than 150 MV/m

  11. A new limit on the rate-density of evaporating black holes

    International Nuclear Information System (INIS)

    1993-01-01

    Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1 x 10 5 pc -3 yr -1 at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude

  12. Involvement of a cytosine side chain in proton transfer in the rate-determining step of ribozyme self-cleavage

    Science.gov (United States)

    Shih, I-hung; Been, Michael D.

    2001-01-01

    Ribozymes of hepatitis delta virus have been proposed to use an active-site cytosine as an acid-base catalyst in the self-cleavage reaction. In this study, we have examined the role of cytosine in more detail with the antigenomic ribozyme. Evidence that proton transfer in the rate-determining step involved cytosine 76 (C76) was obtained from examining cleavage activity of the wild-type and imidazole buffer-rescued C76-deleted (C76Δ) ribozymes in D2O and H2O. In both reactions, a similar kinetic isotope effect and shift in the apparent pKa indicate that the buffer is functionally substituting for the side chain in proton transfer. Proton inventory of the wild-type reaction supported a mechanism of a single proton transfer at the transition state. This proton transfer step was further characterized by exogenous base rescue of a C76Δ mutant with cytosine and imidazole analogues. For the imidazole analogues that rescued activity, the apparent pKa of the rescue reaction, measured under kcat/KM conditions, correlated with the pKa of the base. From these data a Brønsted coefficient (β) of 0.51 was determined for the base-rescued reaction of C76Δ. This value is consistent with that expected for proton transfer in the transition state. Together, these data provide strong support for a mechanism where an RNA side chain participates directly in general acid or general base catalysis of the wild-type ribozyme to facilitate RNA cleavage. PMID:11171978

  13. Limitations to very high rate wire chambers in fixed target geometries

    International Nuclear Information System (INIS)

    Spiegel, L.

    1989-11-01

    The task is to explore physical limitations to the operation of wire chambers in fixed target geometries at an interaction rate of 52 MHz (chosen as it corresponds to the FNAL accelerator rf rate.) That is, to see if there are physical limitations to the operation of gaseous wire chambers at such a high operating rate. A primary proton beam energy of 800 GeV has been assumed although modest increases in the primary energy should not affect the basic conclusion as secondary multiplicity increases logarithmically with center-of-momentum energy. By sustaining a 52 MHz interaction rate it is meant that results from a given interaction are electronically isolated from preceding and subsequent rf buckets, good wire plane efficiency is maintained throughout the active region of the chamber, and the chamber operates in a stable manner throughout the course of a typical fixed target run -- six months to a full year. Other working assumptions include the understanding that chamber electronics -- amplifiers, discriminators, delay elements, encoders -- will not suffer degradation at 52 MHz and that the intensely populated beam regions have been somehow excluded from the chambers. 7 refs., 2 figs

  14. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  15. Effects of population based screening for Chlamydia infections in the Netherlands limited by declining participation rates.

    Directory of Open Access Journals (Sweden)

    Boris V Schmid

    Full Text Available BACKGROUND: A large trial to investigate the effectiveness of population based screening for chlamydia infections was conducted in the Netherlands in 2008-2012. The trial was register based and consisted of four rounds of screening of women and men in the age groups 16-29 years in three regions in the Netherlands. Data were collected on participation rates and positivity rates per round. A modeling study was conducted to project screening effects for various screening strategies into the future. METHODS AND FINDINGS: We used a stochastic network simulation model incorporating partnership formation and dissolution, aging and a sexual life course perspective. Trends in baseline rates of chlamydia testing and treatment were used to describe the epidemiological situation before the start of the screening program. Data on participation rates was used to describe screening uptake in rural and urban areas. Simulations were used to project the effectiveness of screening on chlamydia prevalence for a time period of 10 years. In addition, we tested alternative screening strategies, such as including only women, targeting different age groups, and biennial screening. Screening reduced prevalence by about 1% in the first two screening rounds and leveled off after that. Extrapolating observed participation rates into the future indicated very low participation in the long run. Alternative strategies only marginally changed the effectiveness of screening. Higher participation rates as originally foreseen in the program would have succeeded in reducing chlamydia prevalence to very low levels in the long run. CONCLUSIONS: Decreasing participation rates over time profoundly impact the effectiveness of population based screening for chlamydia infections. Using data from several consecutive rounds of screening in a simulation model enabled us to assess the future effectiveness of screening on prevalence. If participation rates cannot be kept at a sufficient level

  16. Kinetically limited weathering at low denudation rates in semiarid climatic conditions

    Science.gov (United States)

    Schoonejans, Jérôme; Vanacker, Veerle; Opfergelt, Sophie; Ameijeiras-Mariño, Yolanda; Christl, Marcus

    2016-02-01

    Biogeochemical cycling within the Critical Zone depends on the interactions between minerals and fluids controlling chemical weathering and physical erosion rates. In this study, we explore the role of water availability in controlling soil chemical weathering in semiarid climatic conditions. Weathering rates and intensities were evaluated for nine soil profiles located on convex ridge crests of three mountain ranges in the Spanish Betic Cordillera. We combine a geochemical mass balance with 10Be cosmogenic nuclides to constrain chemical weathering intensities and long-term denudation rates. As such, this study presents new data on chemical weathering and 10Be-derived denudation for understudied semiarid climate systems. In the Betic Cordillera, chemical weathering intensities are relatively low (~5 to 30% of the total denudation of the soil) and negatively correlated with the magnitude of the water deficit in soils. Chemical mass losses are inversely related to denudation rates (14-109 mm/kyr) and positively to soil thickness (14-58 cm); these results are consistent with kinetic limitation of chemical weathering rates. A worldwide compilation of chemical weathering data suggests that soil water balance may regulate the coupling between chemical weathering and physical erosion by modulating soil solute fluxes. Therefore, future landscape evolution models that seek to link chemical weathering and physical erosion should include soil water flux as an essential driver of weathering.

  17. C-13-carbohydrate breath tests : Impact of physical activity on the rate-limiting step in lactose utilization

    NARCIS (Netherlands)

    Stellaard, F; Koetse, HA; Elzinga, H; Boverhof, R; Tjoonk, R; Klimp, A; Vegter, D; Liesker, J; Vonk, RJ

    Background: (CO2)-C-13 breath tests can be used to monitor carbohydrate digestion in the small intestine. However, after ingestion of C-13-substrates, (CO2)-C-13 excretion in breath originates from two sources: a digestive/oxidative fraction, derived from the small intestine, and a fermentation

  18. An Empirical Limit on the Kilonova Rate from the DLT40 One Day Cadence Supernova Survey

    Science.gov (United States)

    Yang, Sheng; Valenti, Stefano; Cappellaro, Enrico; Sand, David J.; Tartaglia, Leonardo; Corsi, Alessandra; Reichart, Daniel E.; Haislip, Joshua; Kouprianov, Vladimir

    2017-12-01

    Binary neutron star mergers are important in understanding stellar evolution, the chemical enrichment of the universe via the r-process, the physics of short gamma-ray bursts, gravitational waves, and pulsars. The rates at which these coalescences happen is uncertain, but it can be constrained in different ways. One of those is to search for the optical transients produced at the moment of the merging, called a kilonova, in ongoing supernova (SN) searches. However, until now, only theoretical models for a kilonova light curve were available to estimate their rates. The recent kilonova discovery of AT 2017gfo/DLT17ck gives us the opportunity to constrain the rate of kilonovae using the light curve of a real event. We constrain the rate of binary neutron star mergers using the DLT40 Supernova search and the native AT 2017gfo/DLT17ck light curve obtained with the same telescope and software system. Excluding AT 2017gfo/DLT17ck due to visibility issues, which was only discovered thanks to the aLIGO/aVirgo trigger, no other similar transients were detected during the 13 months of daily cadence observations of ∼2200 nearby (<40 Mpc) galaxies. We find that the rate of BNS mergers is lower than 0.47–0.55 kilonovae per 100 years per 1010 {L}{Bȯ } (depending on the adopted extinction distribution). In volume, this translates to < 0.99× {10}-4{}-0.15+0.19, {{Mpc}}-3 {{yr}}-1 (SNe Ia–like extinction distribution), consistent with previous BNS coalescence rates. Based on our rate limit, and the sensitivity of aLIGO/aVirgo during O2, it is very unlikely that kilonova events are lurking in old pointed galaxy SN search data sets.

  19. Calculation of hydrogen outgassing rate of LHD by recombination limited model

    International Nuclear Information System (INIS)

    Akaishi, K.; Nakasuga, M.

    2002-04-01

    To simulate hydrogen outgassing in the plasma vacuum vessel of LHD, the recombination limited model is presented, where the time evolution of hydrogen concentration in the wall of the plasma vacuum vessel is described by a one-dimensional diffusion equation. The hydrogen outgassing rates when the plasma vacuum vessel is pumped down at room temperature and baked at 100 degC are calculated as a function of pumping time. The calculation shows that the hydrogen outgassing rate of the plasma vacuum vessel can be reduced at least by one order of magnitude due to pumping and baking. This prediction is consistent with the recent result of outgassing reduction observed in the pumping-down and baking of the plasma vacuum vessel in LHD. (author)

  20. Determination of carcinogenic threshold limit values using the tumorigenic dose rate 50% (TD50)

    International Nuclear Information System (INIS)

    Bonvalot, Y.; Oudiz, A.; Hubert, P.; Abenhaim, L.

    1989-01-01

    The objective of the present study is to propose a simple procedure for the determination of Occupational Limit Values (OLVs) based on the TD 50 concept (Tumorigenic Dose Rate 50%). The TD 50 concept was introduced by Peto R. and al. to help classify chemical substances according to their carcinogenic potency. The TD 50 is that dose rate (in mg/KXg body weight/day) which, if administered chronically for the standard lifespan of the species will halve the probability of remaining tumorless throughout that period. Using TD 50 values available for 776 substances, the procedure presented here allows one to determine OLVs corresponding to a fixed excess risk. It is based on a mathematical high-to-low doses extrapolation of the TD 50 . OLVs obtained with this procedure are compared with currently available TLVs and other occupational guidelines. (author)

  1. Kinetically limited weathering at low denudation rates in semi-arid climates

    Science.gov (United States)

    Vanacker, V.; Schoonejans, J.; Opfergelt, S.; Ameijeiras-Marino, Y.; Christl, M.

    2016-12-01

    On Earth, the Critical Zone supports terrestrial life, being the near-surface environment where interactions between the atmosphere, lithosphere, hydrosphere, and biosphere take place Quantitative understanding of the interaction between mechanical rock breakdown, chemical weathering, and physical erosion is essential for unraveling Earth's biogeochemical cycles. In this study, we explore the role of soil water balance on regulating soil chemical weathering under water deficit regimes. Weathering rates and intensities were evaluated for nine soil profiles located on convex ridge crests of three mountain ranges in the Spanish Betic Cordillera. We present and compare quantitative information on soil weathering, chemical depletion and total denudation that were derived based on geochemical mass balance, 10Be cosmogenic nuclides and U-series disequilibria. Soil production rates determined based on U-series isotopes (238U, 234U, 230Th and 226Ra) are of the same order of magnitude as 10Be-derived denudation rates, suggesting steady state soil thickness, in two out of three sampling sites. The chemical weathering intensities are relatively low (˜5 to 30% of the total denudation of the soil) and negatively correlated with the magnitude of the water deficit in soils. Soil weathering extents increase (nonlinearly) with soil thickness and decrease with increasing surface denudation rates, consistent with kinetically limited or controlled weathering. Our study suggests that soil residence time and water availability limit weathering processes in semi-arid climates, which has not been validated previously with field data. An important implication of this finding is that climatic regimes may strongly regulate soil weathering by modulating soil solute fluxes.

  2. Achievable Rates of Cognitive Radio Networks Using Multi-Layer Coding with Limited CSI

    KAUST Repository

    Sboui, Lokman

    2016-03-01

    In a Cognitive Radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU Tx) can be limited or unavailable. Thus, the statistical model is adopted in order to determine the system performance using the outage concept. In this paper, we adopt a new approach using multi-layer-coding (MLC) strategy, i.e., broadcast approach, to enhance spectrum sharing over fading channels. First, we consider a scenario where the secondary transmitter has no CSI of both the link between SU Tx and the primary receiver (cross-link) and its own link. We show that using MLC improves the cognitive rate compared to the rate provided by a singlelayer- coding (SLC). In addition, we observe numerically that 2-Layer coding achieves most of the gain for Rayleigh fading. Second, we analyze a scenario where SU Tx is provided by partial CSI about its link through quantized CSI. We compute its achievable rate adopting the MLC and highlight the improvement over SLC. Finally, we study the case in which the cross-link is perfect, i.e., a cooperative primary user setting, and compare the performance with the previous cases. We present asymptotic analysis at high power regime and show that the cooperation enhances considerably the cognitive rate at high values of the secondary power budget.

  3. Rates and limits of climatic change: Discussion of possible targets; Rates and limits of temperature, precipitation, and sea-level changes

    Energy Technology Data Exchange (ETDEWEB)

    Gleick, P H [Pacific Inst. for SiDES, Berkeley, CA (US); Sassin, W [Landl (AT)

    1990-10-01

    The rate of sea-level rise over the next century is likely to accelerate rapidly and exceed rates of rise experienced over the last several thousand years. Under these conditions, adverse effects on natural ecosystems such as coastal marshes and coral reef islands would be widely observable by 2050, and would be noticeable in vulnerable ecosystems by the year 2000, even under low sea-level rise scenario. Non-linearities and sudden events such as storm surges and a change in storm frequency and intensity could lead to damages even earlier. Similarly, change in temperature and precipitation patterns far greater than those experienced in the last 10000to 100000 years seem likely unless strong actions are taken soon. Rates of change in temperature, precipitation, and sea level over geologic time have often exceeded the rates expected over the next century from global warming. These large excursions, however, were often accompanied by dramatic changes in ecosystems and by large species extinctions, and they occurred when no human infrastructure existed. The adaptive abilities of natural ecosystems can be used to define targets of maximum rates of rise. For coral reef islands and coastal marshes, the maximum rate of accretion of materials is 10 to 15 mm/yr. At this rate, however, many reefs and marshes that accrete materials at slower rates will be inundated and destroyed. Average rates of accretion for marshes are lower - between 2 and 5 mm/yr, and between 5 and 10 mm/yr for coral reefs. Even at these lower rates, some ecosystem losses are to be expected. This information leads to a recommended target for the rate of sea-level rise of between 20 and 50 mm per decade, and a target for absolute sea-level rise of between 0.2 and 0.5 above the 1990 global mean sea level. (authors).

  4. LIMITS ON THE EVENT RATES OF FAST RADIO TRANSIENTS FROM THE V-FASTR EXPERIMENT

    International Nuclear Information System (INIS)

    Wayth, Randall B.; Tingay, Steven J.; Deller, Adam T.; Brisken, Walter F.; Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.

    2012-01-01

    We present the first results from the V-FASTR experiment, a commensal search for fast transient radio bursts using the Very Long Baseline Array (VLBA). V-FASTR is unique in that the widely spaced VLBA antennas provide a discriminant against non-astronomical signals and a mechanism for the localization and identification of events that is not possible with single dishes or short baseline interferometers. Thus, far V-FASTR has accumulated over 1300 hr of observation time with the VLBA, between 90 cm and 3 mm wavelength (327 MHz-86 GHz), providing the first limits on fast transient event rates at high radio frequencies (>1.4 GHz). V-FASTR has blindly detected bright individual pulses from seven known pulsars but has not detected any single-pulse events that would indicate high-redshift impulsive bursts of radio emission. At 1.4 GHz, V-FASTR puts limits on fast transient event rates comparable with the PALFA survey at the Arecibo telescope, but generally at lower sensitivities, and comparable to the 'fly's eye' survey at the Allen Telescope Array, but with less sky coverage. We also illustrate the likely performance of the Phase 1 SKA dish array for an incoherent fast transient search fashioned on V-FASTR.

  5. Performance limits of ICA-based heart rate identification techniques in imaging photoplethysmography

    International Nuclear Information System (INIS)

    Mannapperuma, Kavan; Holton, Benjamin D; Lesniewski, Peter J; Thomas, John C

    2015-01-01

    Imaging photoplethysmography is a relatively new technique for extracting biometric information from video images of faces. This is useful in non-invasive monitoring of patients including neonates or the aged, with respect to sudden infant death syndrome, sleep apnoea, pulmonary disease, physical or mental stress and other cardio-vascular conditions. In this paper, we investigate the limits of detection of the heart rate (HR) while reducing the video quality. We compare the performance of three independent component analysis (ICA) methods (JADE, FastICA, RADICAL), autocorrelation with signal conditioning techniques and identify the most robust approach. We discuss sources of increasing error and other limiting conditions in three situations of reduced signal-to-noise ratio: one where the area of the analyzed face is decreased from 100 to 5%, another where the face area is progressively re-sampled down to a single RGB pixel and one where the HR signal is severely reduced with respect to the boundary noise. In most cases, the cardiac pulse rate can be reliably and accurately detected from videos containing only 5% facial area or from a face occupying just 4 pixels or containing only 5% of the facial HR modulation. (paper)

  6. Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

    Energy Technology Data Exchange (ETDEWEB)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

  7. Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

    KAUST Repository

    Masih, Dilshad

    2015-02-05

    Here, we report for the first time a one-step direct method for sensing halides in aqueous solution using phosphorescence quenching of platinum-cationic porphyrin. This method offers an easy, rapid, environmentally friendly, ultra-sensitive (with a previously unattained detection limit of 1 × 10−12 M) and economical method for the determination of iodide. To fully understand the reaction mechanism responsible for the phosphorescence quenching process, we have employed cutting-edge time-resolved laser spectroscopy with broadband capabilities.

  8. An item response theory evaluation of the young mania rating scale and the montgomery-asberg depression rating scale in the systematic treatment enhancement program for bipolar disorder (STEP-BD).

    Science.gov (United States)

    Prisciandaro, James J; Tolliver, Bryan K

    2016-11-15

    The Young Mania Rating Scale (YMRS) and Montgomery-Asberg Depression Rating Scale (MADRS) are among the most widely used outcome measures for clinical trials of medications for Bipolar Disorder (BD). Nonetheless, very few studies have examined the measurement characteristics of the YMRS and MADRS in individuals with BD using modern psychometric methods. The present study evaluated the YMRS and MADRS in the Systematic Treatment Enhancement Program for BD (STEP-BD) study using Item Response Theory (IRT). Baseline data from 3716 STEP-BD participants were available for the present analysis. The Graded Response Model (GRM) was fit separately to YMRS and MADRS item responses. Differential item functioning (DIF) was examined by regressing a variety of clinically relevant covariates (e.g., sex, substance dependence) on all test items and on the latent symptom severity dimension, within each scale. Both scales: 1) contained several items that provided little or no psychometric information, 2) were inefficient, in that the majority of item response categories did not provide incremental psychometric information, 3) poorly measured participants outside of a narrow band of severity, 4) evidenced DIF for nearly all items, suggesting that item responses were, in part, determined by factors other than symptom severity. Limited to outpatients; DIF analysis only sensitive to certain forms of DIF. The present study provides evidence for significant measurement problems involving the YMRS and MADRS. More work is needed to refine these measures and/or develop suitable alternative measures of BD symptomatology for clinical trials research. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Pre-steady-state kinetic analysis of 1-deoxy-D-xylulose-5-phosphate reductoisomerase from Mycobacterium tuberculosis reveals partially rate-limiting product release by parallel pathways.

    Science.gov (United States)

    Liu, Juan; Murkin, Andrew S

    2012-07-03

    As part of the non-mevalonate pathway for the biosynthesis of the isoprenoid precursor isopentenyl pyrophosphate, 1-deoxy-D-xylulose-5-phosphate (DXP) reductoisomerase (DXR) catalyzes the conversion of DXP into 2-C-methyl-D-erythritol 4-phosphate (MEP) by consecutive isomerization and NADPH-dependent reduction reactions. Because this pathway is essential to many infectious organisms but is absent in humans, DXR is a target for drug discovery. In an attempt to characterize its kinetic mechanism and identify rate-limiting steps, we present the first complete transient kinetic investigation of DXR. Stopped-flow fluorescence measurements with Mycobacterium tuberculosis DXR (MtDXR) revealed that NADPH and MEP bind to the free enzyme and that the two bind together to generate a nonproductive ternary complex. Unlike the Escherichia coli orthologue, MtDXR exhibited a burst in the oxidation of NADPH during pre-steady-state reactions, indicating a partially rate-limiting step follows chemistry. By monitoring NADPH fluorescence during these experiments, the transient generation of MtDXR·NADPH·MEP was observed. Global kinetic analysis supports a model involving random substrate binding and ordered release of NADP(+) followed by MEP. The partially rate-limiting release of MEP occurs via two pathways--directly from the binary complex and indirectly via the MtDXR·NADPH·MEP complex--the partitioning being dependent on NADPH concentration. Previous mechanistic studies, including kinetic isotope effects and product inhibition, are discussed in light of this kinetic mechanism.

  10. High-Pressure Limit Rate Rules for α-H Isomerization of Hydroperoxyalkylperoxy Radicals

    KAUST Repository

    Mohamed, Samah Y

    2018-03-09

    Hydroperoxyalkylperoxy (OOQOOH) radical isomerization is an important low-temperature chain branching reaction within the mechanism of hydrocarbon oxidation. This isomerization may proceed via the migration of the α-hydrogen to the hydroperoxide group. In this work, a combination of high level composite methods - CBS-QB3, G3 and G4 - is used to determine the high-pressure-limit rate parameters for the title reaction. Rate rules for H-migration reactions proceeding through 5-, 6-, 7- and 8-membered ring transitions states are determined. Migrations from primary, secondary and tertiary carbon sites to the peroxy group are considered. Chirality is also investigated by considering two diastereomers for reactants and transition states with two chiral centers. This is important since chirality may influence the energy barrier of the reaction as well as the rotational energy barriers of hindered rotors in chemical species and transition states. The effect of chirality and hydrogen bonding interactions in the investigated energies and rate constants is studied. The results show that while the energy difference between two diastereomers ranges from 0.1 - 3.2 kcal, chirality hardly affects the kinetics, except at low temperatures (atmospheric conditions) or when two chiral centers are present in the reactant. Regarding the effects of the peroxy group position and the H-migration ring size, it is found that in most cases, the 1,5 and 1,6 H-migration reactions have similar rates at low temperatures (below ~830K) since the 1,6 H-migration proceeds via a cyclohexane-like transition state similar to that of the 1,5 H-migration.

  11. 40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

  12. 75 FR 70738 - Gulf Oil Limited Partnership; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2010-11-18

    ... Limited Partnership; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... proceeding of Gulf Oil Limited Partnership's application for market-based rate authority, with an... CFR Part 34, of future issuances of securities and assumptions of liability. Any person desiring to...

  13. Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels.

    Science.gov (United States)

    Capes, Deborah L; Goldschen-Ohm, Marcel P; Arcisio-Miranda, Manoel; Bezanilla, Francisco; Chanda, Baron

    2013-08-01

    Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na(+) channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K(+) current. Fast inactivation is also the main determinant of the refractory period between successive electrical impulses. Although the voltage sensor of domain IV (DIV) has been implicated in fast inactivation, it remains unclear whether the activation of DIV alone is sufficient for fast inactivation to occur. Here, we functionally neutralize each specific voltage sensor by mutating several critical arginines in the S4 segment to glutamines. We assess the individual role of each voltage-sensing domain in the voltage dependence and kinetics of fast inactivation upon its specific inhibition. We show that movement of the DIV voltage sensor is the rate-limiting step for both development and recovery from fast inactivation. Our data suggest that activation of the DIV voltage sensor alone is sufficient for fast inactivation to occur, and that activation of DIV before channel opening is the molecular mechanism for closed-state inactivation. We propose a kinetic model of sodium channel gating that can account for our major findings over a wide voltage range by postulating that DIV movement is both necessary and sufficient for fast inactivation.

  14. Protonation mechanism and location of rate-determining steps for the Ascaris suum nicotinamide adenine dinucleotide-malic enzyme reaction from isotope effects and pH studies

    International Nuclear Information System (INIS)

    Kiick, D.M.; Harris, B.G.; Cook, P.F.

    1986-01-01

    The pH dependence of the kinetic parameters and the primary deuterium isotope effects with nicotinamide adenine dinucleotide (NAD) and also thionicotinamide adenine dinucleotide (thio-NAD) as the nucleotide substrates were determined in order to obtain information about the chemical mechanism and location of rate-determining steps for the Ascaris suum NAD-malic enzyme reaction. The maximum velocity with thio-NAD as the nucleotide is pH-independent from pH 4.2 to 9.6, while with NAD, V decreases below a pK of 4.8. V/K for both nucleotides decreases below a pK of 5.6 and above a pK of 8.9. Both the tartronate pKi and V/Kmalate decrease below a pK of 4.8 and above a pK of 8.9. Oxalate is competitive vs. malate above pH 7 and noncompetitive below pH 7 with NAD as the nucleotide. The oxalate Kis increases from a constant value above a pK of 4.9 to another constant value above a pK of 6.7. The oxalate Kii also increases above a pK of 4.9, and this inhibition is enhanced by NADH. In the presence of thio-NAD the inhibition by oxalate is competitive vs. malate below pH 7. For thio-NAD, both DV and D(V/K) are pH-independent and equal to 1.7. With NAD as the nucleotide, DV decreases to 1.0 below a pK of 4.9, while D(V/KNAD) and D(V/Kmalate) are pH-independent. Above pH 7 the isotope effects on V and the V/K values for NAD and malate are equal to 1.45, the pH-independent value of DV above pH 7. Results indicate that substrates bind to only the correctly protonated form of the enzyme. Two enzyme groups are necessary for binding of substrates and catalysis. Both NAD and malate are released from the Michaelis complex at equal rates which are equal to the rate of NADH release from E-NADH above pH 7. Below pH 7 NADH release becomes more rate-determining as the pH decreases until at pH 4.0 it completely limits the overall rate of the reaction

  15. An upper limit on the contribution of accreting white dwarfs to the type Ia supernova rate.

    Science.gov (United States)

    Gilfanov, Marat; Bogdán, Akos

    2010-02-18

    There is wide agreement that type Ia supernovae (used as standard candles for cosmology) are associated with the thermonuclear explosions of white dwarf stars. The nuclear runaway that leads to the explosion could start in a white dwarf gradually accumulating matter from a companion star until it reaches the Chandrasekhar limit, or could be triggered by the merger of two white dwarfs in a compact binary system. The X-ray signatures of these two possible paths are very different. Whereas no strong electromagnetic emission is expected in the merger scenario until shortly before the supernova, the white dwarf accreting material from the normal star becomes a source of copious X-rays for about 10(7) years before the explosion. This offers a means of determining which path dominates. Here we report that the observed X-ray flux from six nearby elliptical galaxies and galaxy bulges is a factor of approximately 30-50 less than predicted in the accretion scenario, based upon an estimate of the supernova rate from their K-band luminosities. We conclude that no more than about five per cent of type Ia supernovae in early-type galaxies can be produced by white dwarfs in accreting binary systems, unless their progenitors are much younger than the bulk of the stellar population in these galaxies, or explosions of sub-Chandrasekhar white dwarfs make a significant contribution to the supernova rate.

  16. The rate-limiting mechanism of transition metal gettering in multicrystalline silicon

    International Nuclear Information System (INIS)

    McHugo, S.A.; Thompson, A.C.; Imaizumi, M.

    1997-01-01

    Multicrystalline silicon is a very interesting material for terrestrial solar cells. Its low cost and respectable energy conversion efficiency (12-15%) makes it arguably the most cost competitive material for large-volume solar power generation. However, the solar cell efficiency of this material is severely degraded by regions of high minority carrier recombination which have been shown to possess both dislocations and microdefects. These structural defects are known to increase in recombination activity with transition metal decoration. Therefore, gettering of metal impurities from the material would be expected to greatly enhance solar cell performance. Contrary to this rationale, experiments using frontside phosphorus and/or backside aluminum treatments have been found to improve regions with low recombination activity while having little or no effect on the high recombination regions and in turn only slightly improving the overall cell performance. The goal of this research is to determine the mechanism by which gettering is ineffectual on these high recombination regions. The authors have performed studies on integrated circuit (IC) quality single crystal and multicrystalline solar cell silicon (mc-silicon) in the as-grown state and after a variety of processing/gettering steps. With Surface Photovoltage measurements of the minority carrier diffusion length which is inversely proportional to carrier recombination, they have seen that aluminum gettering is effective for improving IC quality material but ineffective for improving the regions of initially low diffusion lengths (high recombination rates) in mc-silicon. Of particular interest is the great increase in diffusion length for IC material as compared to the mc-silicon. Clearly the IC material has benefited to a greater extent from the gettering procedure than the mc-silicon

  17. Does attenuated skin blood flow lower sweat rate and the critical environmental limit for heat balance during severe heat exposure?

    Science.gov (United States)

    Cramer, Matthew N; Gagnon, Daniel; Crandall, Craig G; Jay, Ollie

    2017-02-01

    What is the central question of this study? Does attenuated skin blood flow diminish sweating and reduce the critical environmental limit for heat balance, which indicates maximal heat loss potential, during severe heat stress? What is the main finding and its importance? Isosmotic hypovolaemia attenuated skin blood flow by ∼20% but did not result in different sweating rates, mean skin temperatures or critical environmental limits for heat balance compared with control and volume-infusion treatments, suggesting that the lower levels of skin blood flow commonly observed in aged and diseased populations may not diminish maximal whole-body heat dissipation. Attenuated skin blood flow (SkBF) is often assumed to impair core temperature (T c ) regulation. Profound pharmacologically induced reductions in SkBF (∼85%) lead to impaired sweating, but whether the smaller attenuations in SkBF (∼20%) more often associated with ageing and certain diseases lead to decrements in sweating and maximal heat loss potential is unknown. Seven healthy men (28 ± 4 years old) completed a 30 min equilibration period at 41°C and a vapour pressure (P a ) of 2.57 kPa followed by incremental steps in P a of 0.17 kPa every 6 min to 5.95 kPa. Differences in heat loss potential were assessed by identifying the critical vapour pressure (P crit ) at which an upward inflection in T c occurred. The following three separate treatments elicited changes in plasma volume to achieve three distinct levels of SkBF: control (CON); diuretic-induced isosmotic dehydration to lower SkBF (DEH); and continuous saline infusion to maintain SkBF (SAL). The T c , mean skin temperature (T sk ), heart rate, mean laser-Doppler flux (forearm and thigh; LDF mean ), mean local sweat rate (forearm and thigh; LSR mean ) and metabolic rate were measured. In DEH, a 14.2 ± 5.7% lower plasma volume resulted in a ∼20% lower LDF mean in perfusion units (PU) (DEH, 139 ± 23 PU; CON, 176 ± 22 PU; and SAL

  18. Development of an instrument for direct ozone production rate measurements: measurement reliability and current limitations

    Science.gov (United States)

    Sklaveniti, Sofia; Locoge, Nadine; Stevens, Philip S.; Wood, Ezra; Kundu, Shuvashish; Dusanter, Sébastien

    2018-02-01

    . This type of investigations allows checking whether our understanding of the turnover point between NOx-limited and NOx-saturated regimes of ozone production is well understood and does not require measuring ambient OPR but instead only probing the change in ozone production when NO is added. During IRRONIC, changes in ozone production rates ranging from the limit of detection (3σ) of 6.2 ppbv h-1 up to 20 ppbv h-1 were observed when 6 ppbv of NO was added into the flow tubes.

  19. Estimating reaction rate constants from a two-step reaction: a comparison between two-way and three-way methods

    NARCIS (Netherlands)

    Bijlsma, S.; Smilde, A. K.

    2000-01-01

    In this paper, two different spectral datasets are used in order to estimate reaction rate constants using different algorithms. Dataset 1 consists of short-wavelength near-infrared (SW NIR) spectra taken in time of the two-step epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone using tert-butyl

  20. A one-step separation of human serum high density lipoproteins 2 and 3 by rate-zonal density gradient ultracentrifugation in a swinging bucket rotor

    NARCIS (Netherlands)

    Groot, P.H.E.; Scheek, L.M.; Havekes, L.; Noort, W.L. van; Hooft, F.M. van 't

    1982-01-01

    A method was developed for the separation of the high density lipoprotein subclasses HDL2 and HDL3 from human serum. Six serum samples are fractionated in a single-step ultracentrifugal procedure using the Beckman (SW-40) swinging bucket rotor. The method is based on a difference in flotation rate

  1. 14 CFR 61.415 - What are the limits of a flight instructor certificate with a sport pilot rating?

    Science.gov (United States)

    2010-01-01

    ... certificate with a sport pilot rating? 61.415 Section 61.415 Aeronautics and Space FEDERAL AVIATION... GROUND INSTRUCTORS Flight Instructors With a Sport Pilot Rating § 61.415 What are the limits of a flight instructor certificate with a sport pilot rating? If you hold a flight instructor certificate with a sport...

  2. Stability region of closed-loop pilot-vehicle system for fly-by-wire aircraft with limited actuator rate

    OpenAIRE

    Ying-hui, Li; Liang, Qu; Hao-jun, Xu; Qi-meng, Cao

    2017-01-01

    The category-II PIO (Pilot Induced Oscillations) caused by actuator rate limitation of fly-by-wire airplanes will badly threaten the flight safety. The stability regions of closed-loop pilot-vehicle (CLPV) system with rate limited actuator were studied in this paper to assess stability of such CLPV system. The augmented state  variables were introduced to segregate the rate limited element from the primary  system in order to build the saturation nonlinear model of CLPV system. To get the max...

  3. Quantifying incision rates since the early Miocene: novelties, potentialities and limitations

    Science.gov (United States)

    Sartégou, A.; Braucher, R.; Blard, P. H.; Bourlès, D. L.; Zimmermann, L.; Tibari, B.; Voinchet, P.; Bahain, J. J.; Sorriaux, P.; Leanni, L.; Team, A.

    2017-12-01

    The rates and chronologies of valley incision are closely modulated by the tectonic uplift of active mountain ranges and were controlled by repeated climate changes during the Quaternary. The Pyrenees are a continental collision between the Iberian and Eurasian plates induced a double vergence orogen, which has been considered as a mature mountain range in spite of significant seismicity and evidence of neotectonics. Nevertheless, recent studies indicate that the range may have never reached a steady state. One option for resolving this controversy is to quantify the incision rates since the Miocene by reconstructing the vertical movement of geometric markers. However, the few available ages from the Pyrenean terrace systems do not exceed the middle Pleistocene. To enlarge the time span of this dataset, we studied alluvium-filled horizontal epiphreatic passages in limestone karstic networks, which represent former valley floors. They record the transient position of former local base levels during the process of valley deepening. We used various suitable geochronological methods (26Al/10Be, 10Be/21Ne, ESR and OSL burial durations on quartz) on intrakarstic alluvial deposits from three valleys of the central and eastern Pyrenees, as well as on a recent analogue. In the Pyrenean context, under particular conditions, these geochronometers allow us to document incision processes since 16-13 Ma, and to study influences of external forcing and eustatism. In comparison with other studies, it appears that incision rates are higher in the central Pyrenees and for the Spanish slope. However, the density of horizontal levels on an altimetric range, the geodynamical and paleoclimatic contexts, the reorganization of the drainage networks can make the filling stories of the networks more complex than expected. Indeed, these radiometric approaches may be limited when some formations are reworked inside and/or outside the karst. The validity of dosimetric methods in a mountainous

  4. Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes

    Science.gov (United States)

    Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; Ayala Solares, H. A.; hide

    2014-01-01

    Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of approx.5.0 x 10(exp 14) g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV-TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.

  5. High rate behavior and discharge limits in micro-pattern detectors

    CERN Document Server

    Bressan, A; Pagano, P; Ropelewski, Leszek; Sauli, Fabio; Biagi, S F; Buzulutskov, A F; Gruwé, M; De Lentdecker, G; Mörmann, D; Sharma, A

    1999-01-01

    We present and discuss a set of systematic measurements, carried out with gaseous proportional micro-pattern detectors, in order to assess their maximum gain when irradiated with high-rate soft X-rays and heavily ionizing alpha particles. The inventory of detectors tested includes: micro-strip micromegas, micro-dot, gas electron multiplier, CAT (compteur à trous), trench (or groove), micro-CAT (or WELL) detectors, as well as systems with two elements of gaseous amplification in cascade. We confirm the general trend of all single-stage detectors to follow Raether's criterion, i.e. a spontaneous transition from avalanche to streamer, followed by a discharge, when the avalanche size reaches a value of a few 10 7 ; a noticeable exception is the micro-dot counter holding more than 10 8. In multiple structures, where the gain under irradiation is increased by at least one order of magnitude; we speculate this to be a consequence of a voltage dependence of Raether's limit, larger for low operating potentials. Our c...

  6. Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts

    International Nuclear Information System (INIS)

    Abbott, B.; Abbott, R.; Adhikari, R.; Agresti, J.; Anderson, S.B.; Araya, M.; Armandula, H.; Asiri, F.; Barish, B.C.; Barnes, M.; Barton, M.A.; Bhawal, B.; Billingsley, G.; Black, E.; Blackburn, K.; Bork, R.; Brown, D. A.; Busby, D.; Cardenas, L.; Chandler, A.

    2005-01-01

    We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodeled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From software simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1-3x10 -19 Hz -1/2 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientations. These techniques include using coordinated software signal injections to estimate the network sensitivity, and tuning the analysis to maximize the sensitivity and the livetime, subject to constraints on the background

  7. High rate behavior and discharge limits in micro-pattern detectors

    International Nuclear Information System (INIS)

    Bressan, A.; Hoch, M.; Pagano, P.; Ropelewski, L.; Sauli, F.; Biagi, S.; Buzulutskov, A.; Gruwe, M.; De Lentdecker, G.; Moermann, D.; Sharma, A.

    1999-01-01

    We present and discuss a set of systematic measurements, carried out with gaseous proportional micro-pattern detectors, in order to assess their maximum gain when irradiated with high-rate soft X-rays and heavily ionizing alpha particles. The inventory of detectors tested includes: micro-strips, micromegas, micro-dot, gas electron multiplier, CAT (compteur a trous), trench (or groove), micro-CAT (or WELL) detectors, as well as systems with two elements of gaseous amplification in cascade. We confirm the general trend of all single-stage detectors to follow Raether's criterion, i.e. a spontaneous transition from avalanche to streamer, followed by a discharge, when the avalanche size reaches a value of a few 10 7 ; a noticeable exception is the micro-dot counter holding more than 10 8 . In multiple structures, where the gain is shared between two devices in cascade, the maximum overall gain under irradiation is increased by at least one order of magnitude; we speculate this to be a consequence of a voltage dependence of Raether's limit, larger for low operating potentials. Our conclusion is that only multiple devices can guarantee a sufficient margin of reliability for operation in harsh LHC running conditions

  8. Determining next steps in a hand hygiene improvement initiative by examining variation in hand hygiene compliance rates.

    Science.gov (United States)

    Homa, Karen; Kirkland, Kathryn B

    2011-01-01

    Health care worker hand hygiene (HH) is a major quality and safety concern since poor hand hygiene has been linked with hospital associated infections. Dartmouth-Hitchcock Medical Center has been involved in a 4-year initiative to improve hand hygiene. In 2006, HH compliance occurred 41% of the time and by 2009, it had improved to 91%. We wanted to understand some of the unexplained variability in HH to help determine where to target more specific strategies. To help determine where some of the variability in HH compliance rates occurred, an analysis of means chart was used to determine whether role type of the health care worker and hospital areas had significantly different HH rates compared with the overall HH rate. The overall HH rate between March 2008 and December 2009 was 87%. There was a wide and significant variation between the 16 groups of 2 types of health care workers in 8 hospital areas from the lowest rate of 64% to a high of 96%. Analysis of means revealed significant differences in HH rates relative to the type of worker and hospital areas. Although the method does not inform the organization of what type of intervention will work where and why, it allows high and low performing groups to be identified, so that organizations can learn from them to generate and test theories.

  9. Experimental design for estimating parameters of rate-limited mass transfer: Analysis of stream tracer studies

    Science.gov (United States)

    Wagner, Brian J.; Harvey, Judson W.

    1997-01-01

    Tracer experiments are valuable tools for analyzing the transport characteristics of streams and their interactions with shallow groundwater. The focus of this work is the design of tracer studies in high-gradient stream systems subject to advection, dispersion, groundwater inflow, and exchange between the active channel and zones in surface or subsurface water where flow is stagnant or slow moving. We present a methodology for (1) evaluating and comparing alternative stream tracer experiment designs and (2) identifying those combinations of stream transport properties that pose limitations to parameter estimation and therefore a challenge to tracer test design. The methodology uses the concept of global parameter uncertainty analysis, which couples solute transport simulation with parameter uncertainty analysis in a Monte Carlo framework. Two general conclusions resulted from this work. First, the solute injection and sampling strategy has an important effect on the reliability of transport parameter estimates. We found that constant injection with sampling through concentration rise, plateau, and fall provided considerably more reliable parameter estimates than a pulse injection across the spectrum of transport scenarios likely encountered in high-gradient streams. Second, for a given tracer test design, the uncertainties in mass transfer and storage-zone parameter estimates are strongly dependent on the experimental Damkohler number, DaI, which is a dimensionless combination of the rates of exchange between the stream and storage zones, the stream-water velocity, and the stream reach length of the experiment. Parameter uncertainties are lowest at DaI values on the order of 1.0. When DaI values are much less than 1.0 (owing to high velocity, long exchange timescale, and/or short reach length), parameter uncertainties are high because only a small amount of tracer interacts with storage zones in the reach. For the opposite conditions (DaI ≫ 1.0), solute

  10. Method for calculation of upper limit internal alpha dose rates to aquatic organisms with application of plutonium-239 in plankton

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Baptista, G.B.

    1977-01-01

    A method for the calculation of upper limit internal alpha dose rates to aquatic organisms is presented. The mean alpha energies per disintegration of radionuclides of interest are listed to be used in standard methodologies to calculate dose to aquatic biota. As an application, the upper limits for the alpha dose rates from 239 Pu to the total body of plankton are estimated based on data available in open literature [pt

  11. The natural weathering of staurolite: crystal-surface textures, relative stability, and the rate-determining step

    Science.gov (United States)

    Michael A. Velbel; Charles L. Basso; Michael J. Zieg

    1996-01-01

    Mineral surface-textures on naturally weathered crystals of staurolite [monoclinic, pseudo-orthorhombic; Fe4Al18Si8O46(OH)2] indicate that staurolite weathering is generally interface-limited. Etch pits on naturally weathered staurolites are disk-shaped,...

  12. 75 FR 57762 - MATEP Limited Partnership; MATEP LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2010-09-22

    ...-000] MATEP Limited Partnership; MATEP LLC; Supplemental Notice That Initial Market-Based Rate Filing... the above-referenced proceeding of MATEP Limited Partnership and MATEP LLC's application for market... liability. Any person desiring to intervene or to protest should file with the Federal Energy Regulatory...

  13. Development of a kinetic model of hydrogen absorption and desorption in magnesium and analysis of the rate-determining step

    Science.gov (United States)

    Kitagawa, Yuta; Tanabe, Katsuaki

    2018-05-01

    Mg is promising as a new light-weight and low-cost hydrogen-storage material. We construct a numerical model to represent the hydrogen dynamics on Mg, comprising dissociative adsorption, desorption, bulk diffusion, and chemical reaction. Our calculation shows a good agreement with experimental data for hydrogen absorption and desorption on Mg. Our model clarifies the evolution of the rate-determining processes as absorption and desorption proceed. Furthermore, we investigate the optimal condition and materials design for efficient hydrogen storage in Mg. By properly understanding the rate-determining processes using our model, one can determine the design principle for high-performance hydrogen-storage systems.

  14. α and β deuterium isotope effects in the hydrolysis of naphthalene tetrahydro epoxides: rate-limiting hydrogen migration in the spontaneous hydrolysis of 6-methoxy-1,2,3,4-tetrahydronaphthalene oxide

    International Nuclear Information System (INIS)

    Gillilan, R.E.; Pohl, T.M.; Whalen, D.L.

    1982-01-01

    Data are reported that indicate that 6-methoxy-1,2,3-tetrahydronaphthalene oxide undergoes a spontaneous reaction to yield mostly 6-methyoxy-2-tetralone. Hydrogen-migration is reported to be the rate determining step in the reaction. Reaction mechanisms involving a one-step reaction with a concurrent C-O bond cleavage and hydrogen migration or reversible C-O bond cleavage followed by the rate-limiting hydrogen migration are proposed, but no clear distinction between the schemes is made

  15. Microprocessor-based stepping motor driver

    International Nuclear Information System (INIS)

    Halbig, J.K.; Klosterbuer, S.F.

    1979-09-01

    The Pion Generation for Medical Irradiations (PIGMI) program at the Los Alamos Scientific Laboratory requires a versatile stepping motor driver to do beam diagnostic measurements. A driver controlled by a microprocessor that can move eight stepping motors simultaneously was designed. The driver can monitor and respond to clockwise- and counterclockwise-limit switches, and it can monitor a 0- to 10-V dc position signal. The software controls start and stop ramping and maximum stepping rates. 2 figures, 1 table

  16. Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

    Directory of Open Access Journals (Sweden)

    Peña Carlos F

    2011-02-01

    Full Text Available Abstract Background The oxygen transfer rate (OTR and dissolved oxygen tension (DOT play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax in cultures where the dissolved oxygen tension (DOT was kept constant. Results The results revealed that in the two dissolved oxygen conditions evaluated, strictly controlled by gas blending at 0.5 and 5% DOT, an increase in the agitation rate (from 300 to 700 rpm caused a significant increase in the OTRmax (from 17 to 100 mmol L-1 h-1 for DOT of 5% and from 6 to 70 mmol L-1 h-1 for DOT of 0.5%. This increase in the OTRmax improved alginate production, as well as the specific alginate production rate (SAPR, reaching a maximal alginate concentration of 3.1 g L-1 and a SAPR of 0.031 g alg g biom-1 h-1 in the cultures at OTRmax of 100 mmol L-1 h-1. In contrast, the mean molecular mass (MMM of the alginate isolated from cultures developed under non-oxygen limited conditions increased by decreasing the OTRmax, reaching a maximal of 550 kDa at an OTRmax of 17 mmol L-1 h-1 . However, in the cultures developed under oxygen limitation (0.5% DOT, the MMM of the polymer was practically the same (around 200 kDa at 300 and 700 rpm, and this remained constant throughout the cultivation. Conclusions Overall, our results showed that under oxygen-limited and non oxygen-limited conditions, alginate production and its molecular mass are linked to the OTRmax, independently of the DOT of the culture.

  17. Achievable Rates of Cognitive Radio Networks Using Multi-Layer Coding with Limited CSI

    KAUST Repository

    Sboui, Lokman; Rezki, Zouheir; Alouini, Mohamed-Slim

    2016-01-01

    In a Cognitive Radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU Tx) can be limited or unavailable. Thus, the statistical model is adopted in order to determine the system performance using

  18. Effect of macromolecular crowding on the rate of diffusion-limited ...

    Indian Academy of Sciences (India)

    The enzymatic reaction rate has been shown to be affected by the presence of such macromolecules. A simple numerical model is proposed here based on percolation and diffusion in disordered systems to study the effect of macromolecular crowding on the enzymatic reaction rates. The model qualitatively explains some ...

  19. Rate-determining Step of Flap Endonuclease 1 (FEN1) Reflects a Kinetic Bias against Long Flaps and Trinucleotide Repeat Sequences.

    Science.gov (United States)

    Tarantino, Mary E; Bilotti, Katharina; Huang, Ji; Delaney, Sarah

    2015-08-21

    Flap endonuclease 1 (FEN1) is a structure-specific nuclease responsible for removing 5'-flaps formed during Okazaki fragment maturation and long patch base excision repair. In this work, we use rapid quench flow techniques to examine the rates of 5'-flap removal on DNA substrates of varying length and sequence. Of particular interest are flaps containing trinucleotide repeats (TNR), which have been proposed to affect FEN1 activity and cause genetic instability. We report that FEN1 processes substrates containing flaps of 30 nucleotides or fewer at comparable single-turnover rates. However, for flaps longer than 30 nucleotides, FEN1 kinetically discriminates substrates based on flap length and flap sequence. In particular, FEN1 removes flaps containing TNR sequences at a rate slower than mixed sequence flaps of the same length. Furthermore, multiple-turnover kinetic analysis reveals that the rate-determining step of FEN1 switches as a function of flap length from product release to chemistry (or a step prior to chemistry). These results provide a kinetic perspective on the role of FEN1 in DNA replication and repair and contribute to our understanding of FEN1 in mediating genetic instability of TNR sequences. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Consumers' Interest In Provider Ratings Grows, And Improved Report Cards And Other Steps Could Accelerate Their Use.

    Science.gov (United States)

    Findlay, Steven D

    2016-04-01

    Encouraging patients and consumers to use data and other information in choosing health care providers is an important way to enhance patient engagement and improve the quality of care. The growing use of technology, including smart phones and near-ubiquitous Internet access, provides consumers with easy access to websites that collect and report assessments and ratings of providers, primarily physicians and hospitals. In addition to new technology, recent laws and changes in society and the delivery of care are laying the foundation for greater use by consumers of provider performance report cards. Such use could be accelerated if the shortcomings of current report card efforts were addressed. Recommendations include making online report cards easier to use and more understandable, engaging, substantive, and relevant to consumers' health and medical concerns and choices. Project HOPE—The People-to-People Health Foundation, Inc.

  1. Growth rates, grazing, sinking, and iron limitation of equatorial Pacific phytoplankton

    International Nuclear Information System (INIS)

    Chavez, F.P.; Buck, K.R.; Coale, K.H.; Martin, J.H.; DiTullio, G.R.; Welschmeyer, N.A.; Barber, R.T.; Jacobson, A.C.

    1991-01-01

    Concentrations of phytoplankton and NO 3 are consistently low and high in surface waters of the oceanic eastern and central equatorial Pacific, and phytoplankton populations are dominated by small solitary phytoplankton. Growth rates of natural phytoplankton populations, needed to assess the relative importance of many of the processes considered in the equatorial Pacific, were estimated by several methods. The growth rates of natural phytoplankton populations were found to be ∼0.7 d -1 or 1 biomass doubling d -1 and were similar for all methods. To keep this system in its observed balance requires that loss rates approximate observed growth rates. Grazing rates, measured with a dilution grazing experiment, were high, accounting for a large fraction of the daily production. Additions of various forms of Fe to 5-7-d incubations utilizing ultraclean techniques resulted in significant shifts in autotrophic and heterotrophic assemblages between initial samples, controls, and Fe enrichments, which were presumably due to Fe, grazing by both protistan and metazoan components, and incubation artifacts. Estimated growth rates of small pennate diatoms showed increases in Fe enrichments with respect to controls. The growth rates of the pennate diatoms were similar to those estimated for the larger size fraction of the natural populations

  2. Merits and limitations of the mode switching rate stabilization pacing algorithms in the implantable cardioverter defibrillator.

    Science.gov (United States)

    Dijkman, B; Wellens, H J

    2001-09-01

    The 7250 Jewel AF Medtronic model of ICD is the first implantable device in which both therapies for atrial arrhythmias and pacing algorithms for atrial arrhythmia prevention are available. Feasibility of that extensive atrial arrhythmia management requires correct and synergic functioning of different algorithms to control arrhythmias. The ability of the new pacing algorithms to stabilize the atrial rate following termination of treated atrial arrhythmias was evaluated in the marker channel registration of 600 spontaneously occurring episodes in 15 patients with the Jewel AF. All patients (55+/-15 years) had structural heart disease and documented atrial and ventricular arrhythmias. Dual chamber rate stabilization pacing was present in 245 (41 %) of episodes following arrhythmia termination and was a part of the mode switching operation during which pacing was provided in the dynamic DDI mode. This algorithm could function as the atrial rate stabilization pacing only when there was a slow spontaneous atrial rhythm or in presence of atrial premature beats conducted to the ventricles with a normal AV time. In case of atrial premature beats with delayed or absent conduction to the ventricles and in case of ventricular premature beats, the algorithm stabilized the ventricular rate. The rate stabilization pacing in DDI mode during sinus rhythm following atrial arrhythmia termination was often extended in time due to the device-based definition of arrhythmia termination. This was also the case in patients, in whom the DDD mode with true atrial rate stabilization algorithm was programmed. The rate stabilization algorithms in the Jewel AF applied after atrial arrhythmia termination provide pacing that is not based on the timing of atrial events. Only under certain circumstances the algorithm can function as atrial rate stabilization pacing. Adjustments in availability and functioning of the rate stabilization algorithms might be of benefit for the clinical performance of

  3. Upper limits of the photon fluence rate on CT detectors: Case study on a commercial scanner

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Mats, E-mail: mats.persson@mi.physics.kth.se; Bornefalk, Hans; Danielsson, Mats [Department of Physics, Royal Institute of Technology, Stockholm SE-10691 (Sweden); Bujila, Robert; Nowik, Patrik; Andersson, Henrik [Unit of X-ray Physics, Section of Imaging Physics Solna, Department of Medical Physics, Karolinska University Hospital, Stockholm SE-17176 (Sweden); Kull, Love [Medical Radiation Physics, Sunderby Hospital, Luleå SE-97180 (Sweden); Andersson, Jonas [Department of Radiation Sciences, Radiation Physics, Umeå University, Umeå SE-90185 (Sweden)

    2016-07-15

    Purpose: The highest photon fluence rate that a computed tomography (CT) detector must be able to measure is an important parameter. The authors calculate the maximum transmitted fluence rate in a commercial CT scanner as a function of patient size for standard head, chest, and abdomen protocols. Methods: The authors scanned an anthropomorphic phantom (Kyoto Kagaku PBU-60) with the reference CT protocols provided by AAPM on a GE LightSpeed VCT scanner and noted the tube current applied with the tube current modulation (TCM) system. By rescaling this tube current using published measurements on the tube current modulation of a GE scanner [N. Keat, “CT scanner automatic exposure control systems,” MHRA Evaluation Report 05016, ImPACT, London, UK, 2005], the authors could estimate the tube current that these protocols would have resulted in for other patient sizes. An ECG gated chest protocol was also simulated. Using measured dose rate profiles along the bowtie filters, the authors simulated imaging of anonymized patient images with a range of sizes on a GE VCT scanner and calculated the maximum transmitted fluence rate. In addition, the 99th and the 95th percentiles of the transmitted fluence rate distribution behind the patient are calculated and the effect of omitting projection lines passing just below the skin line is investigated. Results: The highest transmitted fluence rates on the detector for the AAPM reference protocols with centered patients are found for head images and for intermediate-sized chest images, both with a maximum of 3.4 ⋅ 10{sup 8} mm{sup −2} s{sup −1}, at 949 mm distance from the source. Miscentering the head by 50 mm downward increases the maximum transmitted fluence rate to 5.7 ⋅ 10{sup 8} mm{sup −2} s{sup −1}. The ECG gated chest protocol gives fluence rates up to 2.3 ⋅ 10{sup 8} − 3.6 ⋅ 10{sup 8} mm{sup −2} s{sup −1} depending on miscentering. Conclusions: The fluence rate on a CT detector reaches 3 ⋅ 10{sup 8

  4. Lepton asymmetry rate from quantum field theory: NLO in the hierarchical limit

    Energy Technology Data Exchange (ETDEWEB)

    Bödeker, D.; Sangel, M., E-mail: bodeker@physik.uni-bielefeld.de, E-mail: msangel@physik.uni-bielefeld.de [Fakultät für Physik, Universität Bielefeld, 33501 Bielefeld (Germany)

    2017-06-01

    The rates for generating a matter-antimatter asymmetry in extensions of the Standard Model (SM) containing right-handed neutrinos are the most interesting and least trivial co\\-efficients in the rate equations for baryogenesis through thermal leptogenesis. We obtain a relation of these rates to finite-temperature real-time correlation functions, similar to the Kubo formulas for transport coefficients. Then we consider the case of hierarchical masses for the sterile neutrinos. At leading order in their Yukawa couplings we find a simple master formula which relates the rates to a single finite temperature three-point spectral function. It is valid to all orders in g , where g denotes a SM gauge or quark Yukawa coupling. We use it to compute the rate for generating a matter-antimatter asymmetry at next-to-leading order in g in the non-relativistic regime. The corrections are of order g {sup 2}, and they amount to 4% or less.

  5. Patient dose rate: An ultimate limit for spatial and density resolution of scanning systems

    International Nuclear Information System (INIS)

    Kowalski, G.; Wagner, W.

    1979-01-01

    In X-ray scanning systems, picture quality of the reconstructed slices is limited to a maximum spatial as well as density resolution by the applied radiation dose. Density resolution can be improved in proportion to the root of the patient dose, whereas a doubled spatial resolving power requires an eight times higher patient dose, assuming a fixed slice thickness. Only a careful trade-off between the applied patient dose, density resolution and spatial resolution yields a maximal diagnostic value for the physician. Specifications of a scanning system have to take into account these ultimate restrictions, so that picture quality really is limited by the patient's dose rather than by technical constraints. In addition a method is given by which the applied dose can be reduced by focusing the main intensity onto the region of interest, in case that region is known a priori. (orig.) [de

  6. Convergence Rate Analysis of Distributed Gossip (Linear Parameter) Estimation: Fundamental Limits and Tradeoffs

    Science.gov (United States)

    Kar, Soummya; Moura, José M. F.

    2011-08-01

    The paper considers gossip distributed estimation of a (static) distributed random field (a.k.a., large scale unknown parameter vector) observed by sparsely interconnected sensors, each of which only observes a small fraction of the field. We consider linear distributed estimators whose structure combines the information \\emph{flow} among sensors (the \\emph{consensus} term resulting from the local gossiping exchange among sensors when they are able to communicate) and the information \\emph{gathering} measured by the sensors (the \\emph{sensing} or \\emph{innovations} term.) This leads to mixed time scale algorithms--one time scale associated with the consensus and the other with the innovations. The paper establishes a distributed observability condition (global observability plus mean connectedness) under which the distributed estimates are consistent and asymptotically normal. We introduce the distributed notion equivalent to the (centralized) Fisher information rate, which is a bound on the mean square error reduction rate of any distributed estimator; we show that under the appropriate modeling and structural network communication conditions (gossip protocol) the distributed gossip estimator attains this distributed Fisher information rate, asymptotically achieving the performance of the optimal centralized estimator. Finally, we study the behavior of the distributed gossip estimator when the measurements fade (noise variance grows) with time; in particular, we consider the maximum rate at which the noise variance can grow and still the distributed estimator being consistent, by showing that, as long as the centralized estimator is consistent, the distributed estimator remains consistent.

  7. Establishing Upper Limits for Item Ratings for the Angoff Method: Are Resulting Standards More 'Realistic'?

    Science.gov (United States)

    Reid, Jerry B.

    This report investigates an area of uncertainty in using the Angoff method for setting standards, namely whether or not a judge's conceptualizations of borderline group performance are realistic. Ratings are usually made with reference to the performance of this hypothetical group, therefore the Angoff method's success is dependent on this point.…

  8. The Optimal Progressive Income Tax -- The Existence and the Limit Tax Rates

    OpenAIRE

    Mamoru Kaneko

    1981-01-01

    The purpose of this paper is to consider the problem of optimal income taxation in the domain of progressive (convex) income tax function. This paper proves the existence of an optimal tax function and that the optimal marginal and average tax rates tend asymptotically to 100 percent as income level becomes arbitrarily high.

  9. Capitalizing on the Dynamic Features of Excel to Consider Growth Rates and Limits

    Science.gov (United States)

    Taylor, Daniel; Moore-Russo, Deborah

    2012-01-01

    It is common for both algebra and calculus instructors to use power functions of various degrees as well as exponential functions to examine and compare rates of growth. This can be done on a chalkboard, with a graphing calculator, or with a spreadsheet. Instructors often are careful to connect the symbolic and graphical (and occasionally the…

  10. Fundamental limitations in spontaneous emission rate of single-photon sources

    DEFF Research Database (Denmark)

    Bozhevolnyi, Sergey I.; Khurgin, Jacob B.

    2016-01-01

    The rate of single-photon generation by quantum emitters (QEs) can be enhanced by placing a QE inside a resonant structure. This structure can represent an all-dielectric micro-resonator or waveguide and thus be characterized by ultra-low loss and dimensions on the order of wavelength. Or it can ...

  11. Numerical study on flow rate limitation of open capillary channel flow through a wedge

    Directory of Open Access Journals (Sweden)

    Ting-Ting Zhang

    2016-04-01

    Full Text Available The flow characteristics of slender-column flow in wedge-shaped channel under microgravity condition are investigated in this work. The one-dimensional theoretical model is applied to predict the critical flow rate and surface contour of stable flow. However, the one-dimensional model overestimates the critical flow rate for not considering the extra pressure loss. Then, we develop a three-dimensional simulation method with OpenFOAM, a computational fluid dynamics tool, to simulate various phenomena in wedge channels with different lengths. The numerical results are verified with the capillary channel flow experimental data on the International Space Station. We find that the three-dimensional simulation perfectly predicts the critical flow rates and surface contours under various flow conditions. Meanwhile, the general behaviors in subcritical, critical, and supercritical flow are studied in three-dimensional simulation considering variations of flow rate and open channel length. The numerical techniques for three-dimensional simulation is validated for a wide range of configurations and is hopeful to provide valuable guidance for capillary channel flow experiment and efficient liquid management in space.

  12. The Limit Behavior of a Stochastic Logistic Model with Individual Time-Dependent Rates

    Directory of Open Access Journals (Sweden)

    Yilun Shang

    2013-01-01

    Full Text Available We investigate a variant of the stochastic logistic model that allows individual variation and time-dependent infection and recovery rates. The model is described as a heterogeneous density dependent Markov chain. We show that the process can be approximated by a deterministic process defined by an integral equation as the population size grows.

  13. Heart rate monitoring in soccer: interest and limits during competitive match play and training, practical application.

    Science.gov (United States)

    Alexandre, Dellal; da Silva, Cristiano Diniz; Hill-Haas, Stephen; Wong, Del P; Natali, Antonio J; De Lima, Jorge R P; Bara Filho, Mauricio G B; Marins, Joao J C B; Garcia, Emerson Silami; Karim, Chamari

    2012-10-01

    The identification of physiological loads imposed by soccer training or match play reveals essential information, which may help improve training and recovery strategies. Until today, the use of heart rate (HR) monitoring is not standardized in soccer. Thus, the aim of this review was to analyze, determine and compare the exercise intensity (EI) monitored by HR in professional, youth, and recreational soccer players during matches and training sessions using a meta-analysis. Heart rate is one of the most common physiological variables used to determine exercise internal training load. The mean EI recorded during competitive matches was described as 70-80% of VO2max or 80-90% of maximal heart rate (HRmax), independent of the playing level. With respect to HR training zones, approximately 65% of the total match duration is spent at intensity of 70-90% HRmax and rarely below 65% HRmax. However, although HRmax is mostly employed in the literature, monitoring EI should be expressed in relation to reserve heart rate, as it was described as a more reliable indicator of HR, allowing interindividual comparisons. The HR response according to the playing position indicates that midfielders are characterized by the highest EI, followed by forwards and fullbacks. Moreover, in the second half of the match, the EI is lower than that observed during the first half; this reduction could be correlated with the level of the player's physical conditioning. Consequently, coaches may favor the use of interval training or small-sided training games because these are shown to improve both aerobic capacity and the ability to repeat high-intensity actions. Small-sided games allow reaching similar HR responses to those found during interval training and match play but with greater heterogeneity values. Future investigations should include a larger sample of players with special reference to playing position and the expression of EI in percentage of the reserve heart rate, analyzing the

  14. Oxygen permeation flux through La1-ySryFeO3 limited by the carbon monoxide oxidation rate

    NARCIS (Netherlands)

    van Hassel, B.A.; van Hassel, B.A.; ten Elshof, Johan E.; Bouwmeester, Henricus J.M.

    1995-01-01

    The oxygen permeation flux through La1-ySryFeO3-δ (y = 0.1, 0.2) in a large oxygen partial pressure gradient (air/CO, CO2 mixture) was found to be limited by the carbon monoxide oxidation rate at the low oxygen partial pressure side of the membrane. The oxygen permeation flux through the membrane

  15. Extending the durability of cultivar resistance by limiting epidemic growth rates.

    Science.gov (United States)

    Carolan, Kevin; Helps, Joe; van den Berg, Femke; Bain, Ruairidh; Paveley, Neil; van den Bosch, Frank

    2017-09-27

    Cultivar resistance is an essential part of disease control programmes in many agricultural systems. The use of resistant cultivars applies a selection pressure on pathogen populations for the evolution of virulence, resulting in loss of disease control. Various techniques for the deployment of host resistance genes have been proposed to reduce the selection for virulence, but these are often difficult to apply in practice. We present a general technique to maintain the effectiveness of cultivar resistance. Derived from classical population genetics theory; any factor that reduces the population growth rates of both the virulent and avirulent strains will reduce selection. We model the specific example of fungicide application to reduce the growth rates of virulent and avirulent strains of a pathogen, demonstrating that appropriate use of fungicides reduces selection for virulence, prolonging cultivar resistance. This specific example of chemical control illustrates a general principle for the development of techniques to manage the evolution of virulence by slowing epidemic growth rates. © 2017 The Author(s).

  16. High-dose-rate brachytherapy using molds for oral cavity cancer. The technique and its limitations

    International Nuclear Information System (INIS)

    Nishimura, Yasumasa; Yokoe, Yoshihiko; Nagata, Yasushi; Okajima, Kaoru; Nishida, Mitsuo; Hiraoka, Masahiro

    1998-01-01

    With the availability of a high-dose-rate (HDR) remote afterloading device, a Phase I/II protocol was initiated at our institution to assess the toxicity and efficacy of HDR intracavitary brachytherapy, using molds, in the treatment of squamous cell carcinomas of the oral cavity. Eight patients with squamous cell carcinoma of the oral cavity were treated by the technique. The primary sites of the tumors were the buccal mucosa, oral floor, and gingiva. Two of the buccal mucosal cancers were located in the retromolar trigon. For each patient, a customized mold was fabricated, in which two to four afterloading catheters were placed for an 192 Ir HDR source. Four to seven fractions of 3-4 Gy, 5 mm below the mold surface, were given following external radiation therapy of 40-60 Gy/ 2 Gy. The total dose of HDR brachytherapy ranged from 16 to 28Gy. Although a good initial complete response rate of 7/8 (88%) was achieved, there was local recurrence in four of these seven patients. Both of the retromolar trigon tumors showed marginal recurrence. No serious (e.g., ulcer or bone exposure) late radiation damage has been observed thus far in the follow up period of 15-57 months. High-dose-rate brachytherapy using the mold technique seems a safe and useful method for selected early and superficial oral cavity cancer. However, it is not indicated for thick tumors and/or tumors located in the retromolar trigon. (author)

  17. Observation of advanced particle removal rates in pump limiter simulation experiments

    International Nuclear Information System (INIS)

    Goebel, D.M.; Conn, R.W.

    1984-05-01

    The performance of particle removal schemes for density and impurity control in tokamaks and mirror machines depends strongly on the plasma parameters and local recycling near the plasma neutralizier plates and gas pumping ducts. The relationship between plasma density, electron temperature, ion energy and gas flow and particle removal rate through a pumping duct located near a plasma neutralizer plate has been experimentally investigated in the steady state plasma device PISCES. Results indicate that initially the particle removal by pumps at the end of the duct is proportional to the plasma flux to the plate. A nonlinear increase in the pumping rate occurs when the ionization mean free path for neutrals from the plate becomes less than the plasma radius. The transition from a transparent to an opaque plasma due to local ionization of the neutrals produced at the neutralizer plate greatly enhances the particle removal rate by recycling of the neutral gas as it flows away from the neutralizer plate or out of the pumping ducts. Parameters were varied to determine the importance of ballistic scattering of higher energy ions from the plate, but no effects were found in these experiments

  18. Cdc6 is a rate-limiting factor for proliferative capacity during HL60 cell differentiation

    International Nuclear Information System (INIS)

    Barkley, Laura R.; Hong, Hye Kyung; Kingsbury, Sarah R.; James, Michelle; Stoeber, Kai; Williams, Gareth H.

    2007-01-01

    The DNA replication (or origin) licensing pathway represents a critical step in cell proliferation control downstream of growth signalling pathways. Repression of origin licensing through down-regulation of the MCM licensing factors (Mcm2-7) is emerging as a ubiquitous route for lowering proliferative capacity as metazoan cells exit the cell division cycle into quiescent, terminally differentiated and senescent 'out-of-cycle' states. Using the HL60 monocyte/macrophage differentiation model system and a cell-free DNA replication assay, we have undertaken direct biochemical investigations of the coupling of origin licensing to the differentiation process. Our data show that down-regulation of the MCM loading factor Cdc6 acts as a molecular switch that triggers loss of proliferative capacity during early engagement of the somatic differentiation programme. Consequently, addition of recombinant Cdc6 protein to in vitro replication reactions restores DNA replication competence in nuclei prepared from differentiating cells. Differentiating HL60 cells over-expressing either wild-type Cdc6 or a CDK phosphorylation-resistant Cdc6 mutant protein (Cdc6A4) exhibit an extended period of cell proliferation compared to mock-infected cells. Notably, differentiating HL60 cells over-expressing the Cdc6A4 mutant fail to down-regulate Cdc6 protein levels, suggesting that CDK phosphorylation of Cdc6 is linked to its down-regulation during differentiation and the concomitant decrease in cell proliferation. In this experimental model, Cdc6 therefore plays a key role in the sequential molecular events leading to repression of origin licensing and loss of proliferative capacity during execution of the differentiation programme

  19. Effects of a finite melt on the thickness and composition of liquid phase epitaxial InGaAsP and InGaAs layers grown by the diffusion-limited step-cooling technique

    International Nuclear Information System (INIS)

    Cook, L.W.; Tashima, M.M.; Stillman, G.E.

    1980-01-01

    The thickness of InGaAsP (lambda/sub g/=1.15 μm) and InGaAs (lambda/sub g/=1.68 μm) liquid phase epitaxial layers grown on (100) InP substrates by the step-cooling technique has been measured as a function of growth time. (lambda/sub g/ is defined as the wavelength corresponding to the energy gap of the epitaxial layer.) For growth times much less than the shortest diffusion time tau/sub i/=l 2 /D/sub i/ of the melt constituents, where l is the melt height and D/sub i/ is the diffusivity of each component in the melt, the thickness is consistent with diffusion-limited theory, and the composition is constant. The time at which the growth rate deviates sharply from diffusion-limited theory and beyond which constant composition growth can no longer be maintained has been determined for the melt size used in our experiments and can be estimated for any melt size

  20. Global synchronization of complex dynamical networks through digital communication with limited data rate.

    Science.gov (United States)

    Wang, Yan-Wu; Bian, Tao; Xiao, Jiang-Wen; Wen, Changyun

    2015-10-01

    This paper studies the global synchronization of complex dynamical network (CDN) under digital communication with limited bandwidth. To realize the digital communication, the so-called uniform-quantizer-sets are introduced to quantize the states of nodes, which are then encoded and decoded by newly designed encoders and decoders. To meet the requirement of the bandwidth constraint, a scaling function is utilized to guarantee the quantizers having bounded inputs and thus achieving bounded real-time quantization levels. Moreover, a new type of vector norm is introduced to simplify the expression of the bandwidth limit. Through mathematical induction, a sufficient condition is derived to ensure global synchronization of the CDNs. The lower bound on the sum of the real-time quantization levels is analyzed for different cases. Optimization method is employed to relax the requirements on the network topology and to determine the minimum of such lower bound for each case, respectively. Simulation examples are also presented to illustrate the established results.

  1. Flavin as an Indicator of the Rate-Limiting Factor for Microbial Current Production in Shewanella oneidensis MR-1

    International Nuclear Information System (INIS)

    Saito, Junki; Hashimoto, Kazuhito; Okamoto, Akihiro

    2016-01-01

    Microbial electrode catalysis such as microbial fuel cells or electrosynthesis involves electron exchange with the electrodes located at the cell exterior; i.e., extracellular electron transport (EET). Despite the vast amount of research on the kinetics of EET to optimize the catalysis rate, the relevance of other factors, including upstream metabolic reactions, has scarcely been investigated. Herein, we report an in vivo electrochemical assay to confirm whether EET limits anodic current production (j) for the lactate oxidation of Shewanella oneidensis MR-1. Addition of riboflavin, which specifically enhances the EET rate, increased j only in the early phase before j saturation. In contrast, when we removed a trace metal ion necessary for upstream reactions from the electrolyte, a significant decrease in j and the lactate consumption rate was observed only after j saturation. These data suggest that the limiting factor for j shifted from EET to upstream reactions, highlighting the general importance of enhancing, for example, microbial metabolism, especially for long-standing practical applications. Our concept to specifically control the rate of EET could be applicable to other bioelectrode catalysis systems as a strategy to monitor their rate-limiting factors.

  2. Easy to use program “Simkine3” for simulating kinetic profiles of multi-step chemical Systems and optimisation of predictable rate coefficients therein

    Directory of Open Access Journals (Sweden)

    S.B. Jonnalagadda

    2012-08-01

    Full Text Available ‘Simkine3’, a Delphi based software is developed to simulate the kinetic schemes of complex reaction mechanisms involving multiple sequential and competitive elementary steps for homogeneous and heterogeneous chemical reactions. Simkine3 is designed to translate the user specified mechanism into chemical first-order differential equations (ODEs and optimise the estimated rate constants in such a way that simulated curves match the experimental kinetic profiles. TLSoda which uses backward differentiation method is utilised to solve resulting ODEs and Downhill Simplex method is used to optimise the estimated rate constants in a robotic way. An online help file is developed using HelpScrible Demo to guide the users of Simkine3. The versatility of the software is demonstrated by simulating the complex reaction between methylene violet and acidic bromate, a reaction which exhibits complex nonlinear kinetics. The new software is validated after testing it on a 19-step intricate mechanism involving 15 different species. The kinetic profiles of multiple simulated curves, illustrating the effect of initial concentrations of bromate, and bromide were matched with the corresponding experimental curves.DOI: http://dx.doi.org/10.4314/bcse.v26i2.10

  3. Maximal heart rate does not limit cardiovascular capacity in healthy humans

    DEFF Research Database (Denmark)

    Munch, G D W; Svendsen, J H; Damsgaard, R

    2014-01-01

    In humans, maximal aerobic power (VO2 max ) is associated with a plateau in cardiac output (Q), but the mechanisms regulating the interplay between maximal heart rate (HRmax) and stroke volume (SV) are unclear. To evaluate the effect of tachycardia and elevations in HRmax on cardiovascular function...... and capacity during maximal exercise in healthy humans, 12 young male cyclists performed incremental cycling and one-legged knee-extensor exercise (KEE) to exhaustion with and without right atrial pacing to increase HR. During control cycling, Q and leg blood flow increased up to 85% of maximal workload (WLmax...... and RAP (P healthy...

  4. Testing the limits of optimality: the effect of base rates in the Monty Hall dilemma.

    Science.gov (United States)

    Herbranson, Walter T; Wang, Shanglun

    2014-03-01

    The Monty Hall dilemma is a probability puzzle in which a player tries to guess which of three doors conceals a desirable prize. After an initial selection, one of the nonchosen doors is opened, revealing that it is not a winner, and the player is given the choice of staying with the initial selection or switching to the other remaining door. Pigeons and humans were tested on two variants of the Monty Hall dilemma, in which one of the three doors had either a higher or a lower chance of containing the prize than did the other two options. The optimal strategy in both cases was to initially choose the lowest-probability door available and then switch away from it. Whereas pigeons learned to approximate the optimal strategy, humans failed to do so on both accounts: They did not show a preference for low-probability options, and they did not consistently switch. An analysis of performance over the course of training indicated that pigeons learned to perform a sequence of responses on each trial, and that sequence was one that yielded the highest possible rate of reinforcement. Humans, in contrast, continued to vary their responses throughout the experiment, possibly in search of a more complex strategy that would exceed the maximum possible win rate.

  5. Opportunistic mammography screening provides effective detection rates in a limited resource healthcare system.

    Science.gov (United States)

    Teh, Yew-Ching; Tan, Gie-Hooi; Taib, Nur Aishah; Rahmat, Kartini; Westerhout, Caroline Judy; Fadzli, Farhana; See, Mee-Hoong; Jamaris, Suniza; Yip, Cheng-Har

    2015-05-15

    Breast cancer is the leading cause of cancer deaths in women world-wide. In low and middle income countries, where there are no population-based mammographic screening programmes, late presentation is common, and because of inadequate access to optimal treatment, survival rates are poor. Mammographic screening is well-studied in high-income countries in western populations, and because it has been shown to reduce breast cancer mortality, it has become part of the healthcare systems in such countries. However the performance of mammographic screening in a developing country is largely unknown. This study aims to evaluate the performance of mammographic screening in Malaysia, a middle income country, and to compare the stage and surgical treatment of screen-detected and symptomatic breast cancer. A retrospective review of 2510 mammograms performed from Jan to Dec 2010 in a tertiary medical centre is carried out. The three groups identified are the routine (opportunistic) screening group, the targeted (high risk) screening group and the diagnostic group. The performance indicators of each group is calculated, and stage at presentation and treatment between the screening and diagnostic group is analyzed. The cancer detection rate in the opportunistic screening group, targeted screening group, and the symptomatic group is 0.5 %, 1.25 % and 26 % respectively. The proportion of ductal carcinoma in situ is 23.1 % in the two screening groups compared to only 2.5 % in the diagnostic group. Among the opportunistic screening group, the cancer detection rate was 0.2 % in women below 50 years old compared to 0.65 % in women 50 years and above. The performance indicators are within international standards. Early-staged breast cancer (Stage 0-2) were 84.6 % in the screening groups compared to 61.1 % in the diagnostic group. From the results, in a setting with resource constraints, targeted screening of high risk individuals will give a higher yield, and if more resources are

  6. Highway crash rates and age-related driver limitations: Literature review and evaluation of data bases

    Energy Technology Data Exchange (ETDEWEB)

    Hu, P.S. [Oak Ridge National Lab., TN (United States); Young, J.R. [Tennessee Univ., Knoxville, TN (United States); Lu, An [Oak Ridge Associated Universities, Inc., TN (United States)

    1993-08-01

    American society is undergoing a major demographic transformation that is resulting in a larger proportion of older individuals in the population. Moreover, recent travel surveys show that an increasing number of older individuals are licensed to drive and that they drive more than their same age cohort a decade ago. However, they continue to take shorter trips than younger drivers and they avoid driving during congested hours. This recent demographic transformation in our society, the graying of America, coupled with the increasing mobility of the older population impose a serious highway safety issue that cannot be overlooked. Some of the major concerns are the identification of ``high-risk`` older drivers and the establishment of licensing guidelines and procedures that are based on conclusive scientific evidence. Oak Ridge National Laboratory`s (ORNL) objectives in this project can be characterized by the following tasks: Review and evaluate the 1980 American Association of Motor Vehicle Administrators (AAMVA) and National Highway Traffic Safety Administration (NHTSA) licensing guidelines. Determine whether the license restriction recommended in the 1980 AAMVA and NHTSA guidelines was based on scientific evidence or on judgement of medical advisors. Identify in the scientific literature any medical conditions which are found to be highly associated with highway crashes, and which are not mentioned in the 1980 guidelines. Summarize States` current licensing practices for drivers with age-related physical and mental limitations. Identify potential data sources to establish conclusive evidence on age-related functional impairments and highway crashes.

  7. Environmental and ecological conditions at Arctic breeding sites have limited effects on true survival rates of adult shorebirds

    Science.gov (United States)

    Weiser, Emily L.; Lanctot, Richard B.; Brown, Stephen C.; Gates, H. River; Bentzen, Rebecca L.; Bêty, Joël; Boldenow, Megan L.; English, Willow B.; Franks, Samantha E.; Koloski, Laura; Kwon, Eunbi; Lamarre, Jean-Francois; Lank, David B.; Liebezeit, Joseph R.; McKinnon, Laura; Nol, Erica; Rausch, Jennie; Saalfeld, Sarah T.; Senner, Nathan R.; Ward, David H.; Woodard, Paul F.; Sandercock, Brett K.

    2018-01-01

    Many Arctic shorebird populations are declining, and quantifying adult survival and the effects of anthropogenic factors is a crucial step toward a better understanding of population dynamics. We used a recently developed, spatially explicit Cormack–Jolly–Seber model in a Bayesian framework to obtain broad-scale estimates of true annual survival rates for 6 species of shorebirds at 9 breeding sites across the North American Arctic in 2010–2014. We tested for effects of environmental and ecological variables, study site, nest fate, and sex on annual survival rates of each species in the spatially explicit framework, which allowed us to distinguish between effects of variables on site fidelity versus true survival. Our spatially explicit analysis produced estimates of true survival rates that were substantially higher than previously published estimates of apparent survival for most species, ranging from S = 0.72 to 0.98 across 5 species. However, survival was lower for the arcticolasubspecies of Dunlin (Calidris alpina arcticola; S = 0.54), our only study taxon that migrates through the East Asian–Australasian Flyway. Like other species that use that flyway, arcticola Dunlin could be experiencing unsustainably low survival rates as a result of loss of migratory stopover habitat. Survival rates of our study species were not affected by timing of snowmelt or summer temperature, and only 2 species showed minor variation among study sites. Furthermore, although previous reproductive success, predator abundance, and the availability of alternative prey each affected survival of one species, no factors broadly affected survival across species. Overall, our findings of few effects of environmental or ecological variables suggest that annual survival rates of adult shorebirds are generally robust to conditions at Arctic breeding sites. Instead, conditions at migratory stopovers or overwintering sites might be driving adult survival rates and should be the

  8. Formation Rate-Limited Pharmacokinetics of Biologically Active Epoxy Transformers of Prodrug Treosulfan.

    Science.gov (United States)

    Romański, Michał; Kasprzyk, Anna; Karbownik, Agnieszka; Szałek, Edyta; Główka, Franciszek K

    2016-05-01

    A prodrug treosulfan (TREO) is being evaluated in clinical trials as a myeloablative agent before hematopoietic stem cell transplantation. The active derivatives of TREO, monoepoxide (EBDM), and diepoxide (DEB) are formed in a pH-dependent nonenzymatic reaction. The aim of the study was to investigate pharmacokinetics of the TREO epoxy transformers in a rabbit model and explain the causes of low plasma concentrations of EBDM and DEB observed in patients receiving high-dose TREO before hematopoietic stem cell transplantation. New Zealand white rabbits (n = 5 per cohort) received an intravenous infusion of TREO (group I), injection of DEB (group II), and injection of a solution containing EBDM (group III). When EBDM and DEB were administered to the rabbits, they underwent a very rapid elimination (half-life 0.069 and 0.046 h) associated with a high systemic clearance (10.0 and 14.0 L h(-1) kg(-1)). After administration of TREO, the t1/2 of EBDM was statistically equal to the t1/2 of the prodrug (1.6 h). To conclude, after administration of TREO, its epoxy transformers demonstrate a formation-limited elimination. Then EBDM and DEB have the same elimination half-life as TREO, but the levels of EBDM and DEB in the body, including plasma, are much lower than TREO on account of their inherently high clearance. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  9. Limitations of heterogeneous models of liquid dynamics: very slow rate exchange in the excess wing.

    Science.gov (United States)

    Samanta, Subarna; Richert, Ranko

    2014-02-07

    For several molecular glass formers, the nonlinear dielectric effects (NDE's) are investigated for the so-called excess wing regime, i.e., for the relatively high frequencies between 10(2) and 10(7) times the peak loss frequency. It is found that significant nonlinear behavior persists across the entire frequency window of this study, and that its magnitude traces the temperature dependence of the activation energy. A time resolved measurement of the dielectric loss at fields up to 480 kV/cm across tens of thousands of periods reveals that it takes an unexpectedly long time for the steady state NDE to develop. For various materials and at different temperatures and frequencies, it is found that the average structural relaxation with time scale τα governs the equilibration of these fast modes that are associated with time constants τ which are up to 10(7) times shorter than τα. It is argued that true indicators of structural relaxation (such as rate exchange and aging) of these fast modes are slaved to macroscopic softening on the time scale of τα, and thus many orders of magnitude slower than the time constant of the mode itself.

  10. A first-passage scheme for determination of overall rate constants for non-diffusion-limited suspensions

    Science.gov (United States)

    Lu, Shih-Yuan; Yen, Yi-Ming

    2002-02-01

    A first-passage scheme is devised to determine the overall rate constant of suspensions under the non-diffusion-limited condition. The original first-passage scheme developed for diffusion-limited processes is modified to account for the finite incorporation rate at the inclusion surface by using a concept of the nonzero survival probability of the diffusing entity at entity-inclusion encounters. This nonzero survival probability is obtained from solving a relevant boundary value problem. The new first-passage scheme is validated by an excellent agreement between overall rate constant results from the present development and from an accurate boundary collocation calculation for the three common spherical arrays [J. Chem. Phys. 109, 4985 (1998)], namely simple cubic, body-centered cubic, and face-centered cubic arrays, for a wide range of P and f. Here, P is a dimensionless quantity characterizing the relative rate of diffusion versus surface incorporation, and f is the volume fraction of the inclusion. The scheme is further applied to random spherical suspensions and to investigate the effect of inclusion coagulation on overall rate constants. It is found that randomness in inclusion arrangement tends to lower the overall rate constant for f up to the near close-packing value of the regular arrays because of the inclusion screening effect. This screening effect turns stronger for regular arrays when f is near and above the close-packing value of the regular arrays, and consequently the overall rate constant of the random array exceeds that of the regular array. Inclusion coagulation too induces the inclusion screening effect, and leads to lower overall rate constants.

  11. Influence of methanol/sorbitol co-feeding rate on pAOX1 induction in a Pichia pastoris Mut+ strain in bioreactor with limited oxygen transfer rate.

    Science.gov (United States)

    Carly, F; Niu, H; Delvigne, F; Fickers, P

    2016-04-01

    High Pichia pastoris biomass density could be obtained using high co-feeding rate of methanol and sorbitol in a fed-batch or continuous culture, while further higher feeding rate finally leads to oxygen limitation in bioreactor. In the literature, there is lack of report about AOX1 promoter regulation with regard to dissolved oxygen level (DO). Therefore, in this work, chemostat cultures were performed to investigate the cell growth, metabolism and regulation of the AOX1 promoter (pAOX1) regarding co-feeding rate of optimized methanol/sorbitol mixture (methanol fraction 0.60 C-mol/C-mol) using a P. pastoris Mut+/pAOX1-lacZ strain. The oxygen transfer rates (OTR) in bioreactor were kept in the range of typical values of large bioreactor, i.e., 4-8 g/(L h) if DO equals 30 % saturation or 5-10 g/(L h) if DO nears zero. For DO >0, an increase of the carbon fed led to an increase of pAOX1 induction. By contrast, when dissolved oxygen was completely depleted, methanol accumulated, causing a 30 % decrease of pAOX1 induction. However, this decrease is more likely to be lined to methanol accumulation than to low level of dissolved oxygen (sorbitol co-feeding allowed cells to adapt to oxygen transient limitations that often occur at industrial scale with reduced effect on pAOX1 induction. The optimal feeding rate tested here was 6.6 mmol C (DCW h)(-1) at an OTR of 8.28 g O2(L h)(-1) with over fivefold pAOX1 induction (probably directly associated with target protein productivity) compared with previous work.

  12. Spectrum of Slip Processes on the Subduction Interface in a Continuum Framework Resolved by Rate-and State Dependent Friction and Adaptive Time Stepping

    Science.gov (United States)

    Herrendoerfer, R.; van Dinther, Y.; Gerya, T.

    2015-12-01

    To explore the relationships between subduction dynamics and the megathrust earthquake potential, we have recently developed a numerical model that bridges the gap between processes on geodynamic and earthquake cycle time scales. In a self-consistent, continuum-based framework including a visco-elasto-plastic constitutive relationship, cycles of megathrust earthquake-like ruptures were simulated through a purely slip rate-dependent friction, albeit with very low slip rates (van Dinther et al., JGR, 2013). In addition to much faster earthquakes, a range of aseismic slip processes operate at different time scales in nature. These aseismic processes likely accommodate a considerable amount of the plate convergence and are thus relevant in order to estimate the long-term seismic coupling and related hazard in subduction zones. To simulate and resolve this wide spectrum of slip processes, we innovatively implemented rate-and state dependent friction (RSF) and an adaptive time-stepping into our continuum framework. The RSF formulation, in contrast to our previous friction formulation, takes the dependency of frictional strength on a state variable into account. It thereby allows for continuous plastic yielding inside rate-weakening regions, which leads to aseismic slip. In contrast to the conventional RSF formulation, we relate slip velocities to strain rates and use an invariant formulation. Thus we do not require the a priori definition of infinitely thin, planar faults in a homogeneous elastic medium. With this new implementation of RSF, we succeed to produce consistent cycles of frictional instabilities. By changing the frictional parameter a, b, and the characteristic slip distance, we observe a transition from stable sliding to stick-slip behaviour. This transition is in general agreement with predictions from theoretical estimates of the nucleation size, thereby to first order validating our implementation. By incorporating adaptive time-stepping based on a

  13. STEADY-STATE HEAT REJECTION RATES FOR A COAXIAL BOREHOLE HEAT EXCHANGER DURING PASSIVE AND ACTIVE COOLING DETERMINED WITH THE NOVEL STEP THERMAL RESPONSE TEST METHOD

    Directory of Open Access Journals (Sweden)

    Marija Macenić

    2018-01-01

    Full Text Available At three locations in Zagreb, classical and extended thermal response test (TRT was conducted on installed coaxial heat exchangers. With classic TR test, thermogeological properties of the ground and thermal resistance of the borehole were determined at each location. It is seen that thermal conductivity of the ground varies, due to difference in geological profile of the sites. In addition, experimental research of steady-state thermal response step test (SSTRST was carried out to determine heat rejection rates for passive and active cooling in steady state regime. Results showed that heat rejection rate is only between 8-11 W/m, which indicates that coaxial system is not suitable for passive cooling demands. Furthermore, the heat pump in passive cooling mode uses additional plate heat exchanger where there is additional temperature drop of working fluid by approximately 1,5 °C. Therefore, steady-state rejection rate for passive cooling is even lower for a real case project. Coaxial heat exchanger should be always designed for an active cooling regime with an operation of a heat pump compressor in a classical vapour compression refrigeration cycle.

  14. Brittleness and elastic limit of iron-aluminium 40 at high strain rates; Fragilite et limite elastique du fer-aluminium 40 aux grandes vitesses de deformation

    Energy Technology Data Exchange (ETDEWEB)

    Cottu, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    Iron-aluminium 40 - a B2 ordered solid solution - was tensile tested to provide information on the brittleness of this alloy and its dependence on strain rate and temperature. For slow strain rates (0.34 per cent s{sup -1}) cleaved fracture prevails when temperature is kept below 400 deg. C, while a ductile rupture is observed, with an almost 100 per cent necking at higher temperatures. In this case, recrystallization occurs during the deformation. For higher strain rates - 335 per cent s{sup -1}), a ductility reduction - owed to intergranular fracture - precedes the brittle-ductile transition. This property may be bound to the peak on the yield stress temperature curve, which is itself connected to the ordered structure of this alloy. (author) [French] Les essais de traction que nous avons effectues sur le fer-aluminium 40, solution solide ordonnee de type B2, ont pour but de preciser l'influence de la vitesse de deformation et de la temperature sur la fragilite de l'alliage. Pour les faibles vitesses (0,34 pour cent s{sup -1}), la rupture est surtout clivee si la temperature est inferieure a 400 deg. C, puis ductile avec une striction voisine de 100 pour cent aux temperatures superieures; la recristallisation intervient alors ou cours meme de la deformation. Aux vitesses elevees (335 pour cent s{sup -1}) la transition fragile-ductile est precedee d'une chute de ductilite liee a une decohesion intergranulaire. Nous avons associe cette derniere propriete a la presence d'un pic de limite elastique apparaissant a chaud, a vitesse elevee et pouvant etre relie au caractere ordonne de l'alliage. (auteur)

  15. Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting.

    Science.gov (United States)

    Rashed-Ul Islam, S M; Jahan, Munira; Tabassum, Shahina

    2015-01-01

    Virological monitoring is the best predictor for the management of chronic hepatitis B virus (HBV) infections. Consequently, it is important to use the most efficient, rapid and cost-effective testing systems for HBV DNA quantification. The present study compared the performance characteristics of a one-step HBV polymerase chain reaction (PCR) vs the two-step HBV PCR method for quantification of HBV DNA from clinical samples. A total of 100 samples consisting of 85 randomly selected samples from patients with chronic hepatitis B (CHB) and 15 samples from apparently healthy individuals were enrolled in this study. Of the 85 CHB clinical samples tested, HBV DNA was detected from 81% samples by one-step PCR method with median HBV DNA viral load (VL) of 7.50 × 10 3 lU/ml. In contrast, 72% samples were detected by the two-step PCR system with median HBV DNA of 3.71 × 10 3 lU/ml. The one-step method showed strong linear correlation with two-step PCR method (r = 0.89; p Tabassum S. Evaluation of a Rapid One-step Real-time PCR Method as a High-throughput Screening for Quantification of Hepatitis B Virus DNA in a Resource-limited Setting. Euroasian J Hepato-Gastroenterol 2015;5(1):11-15.

  16. Biological effect of pulsed dose rate brachytherapy with stepping sources if short half-times of repair are present in tissues

    International Nuclear Information System (INIS)

    Fowler, Jack F.; Limbergen, Erik F.M. van

    1997-01-01

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR) for local tissue dose rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. Increased effect is more likely for tissues with short half-times of repair of the order of a few minutes, similar to pulse durations. Methods and Materials: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to exponential repair. The situation with two components of T (1(2)) is addressed. A constant overall time of 140 h and a constant total dose of 70 Gy were assumed throughout, the continuous low dose rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, covering the gap in an earlier publication. Four schedules were examined: doses per pulse of 0.5, 1, 1.5, and 2 Gy given at repetition frequencies of 1, 2, 3, and 4 h, respectively, each with a range of assumed half-times of repair of 4 min to 1.5 h. Results are presented for late-responding tissues, the differences from CLDR being two or three times greater than for early-responding tissues and most tumors. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (2 Gy) if the half-time of repair in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in tissue, and--when T (1(2)) is short--the instantaneous dose rate. Maximum ratios of PDR/CLDR occur when the dose rate is such that pulse duration is approximately equal to T (1(2)) . As dose rate in the pulse is increased, a plateau of effect is reached, for most T (1(2)) s, above 10 to 20 Gy/h, which is

  17. Light stop mass limits from Higgs rate measurements in the MSSM: is MSSM electroweak baryogenesis still alive after all?

    Energy Technology Data Exchange (ETDEWEB)

    Liebler, Stefan [Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, 22607 Hamburg (Germany); Profumo, Stefano; Stefaniak, Tim [Department of Physics and Santa Cruz Institute for Particle Physics (SCIPP),University of California Santa Cruz, CA 95064 (United States)

    2016-04-22

    We investigate the implications of the Higgs rate measurements from Run 1 of the LHC for the mass of the light scalar top partner (stop) in the Minimal Supersymmetric Standard Model (MSSM). We focus on light stop masses, and we decouple the second, heavy stop and the gluino to the multi-TeV range in order to obtain a Higgs mass of ∼125 GeV. We derive lower mass limits for the light stop within various scenarios, taking into account the effects of a possibly light scalar tau partner (stau) or chargino on the Higgs rates, of additional Higgs decays to undetectable “new physics”, as well as of non-decoupling of the heavy Higgs sector. Under conservative assumptions, the stop can be as light as 123 GeV. Relaxing certain theoretical and experimental constraints, such as vacuum stability and model-dependent bounds on sparticle masses from LEP, we find that the light stop mass can be as light as 116 GeV. Our indirect limits are complementary to direct limits on the light stop mass from collider searches and have important implications for electroweak baryogenesis in the MSSM as a possible explanation for the observed matter-antimatter asymmetry of the Universe.

  18. Light stop mass limits from Higgs rate measurements in the MSSM. Is MSSM electroweak baryogenesis still alive after all?

    Energy Technology Data Exchange (ETDEWEB)

    Liebler, Stefan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Profumo, Stefano; Stefaniak, Tim [California Univ., Santa Cruz, CA (United States). Dept. of Physics; California Univ., Santa Cruz, CA (United States). Santa Cruz Inst. for Particle Physics (SCIPP)

    2015-12-15

    We investigate the implications of the Higgs rate measurements from Run 1 of the LHC for the mass of the light scalar top partner (stop) in the Minimal Supersymmetric Standard Model (MSSM). We focus on light stop masses, and we decouple the second, heavy stop and the gluino to the multi-TeV range in order to obtain a Higgs mass of ∝125 GeV. We derive lower mass limits for the light stop within various scenarios, taking into account the effects of a possibly light scalar tau partner (stau) or chargino on the Higgs rates, of additional Higgs decays to undetectable new physics, as well as of non-decoupling of the heavy Higgs sector. Under conservative assumptions, the stop can be as light as 123 GeV. Relaxing certain theoretical and experimental constraints, such as vacuum stability and model-dependent bounds on sparticle masses from LEP, we find that the light stop mass can be as light as 116 GeV. Our indirect limits are complementary to direct limits on the light stop mass from collider searches and have important implications for electroweak baryogenesis in the MSSM as a possible explanation for the observed matter-antimatter asymmetry of the Universe.

  19. Comparison and limitations of three different bulk etch rate measurement methods used for gamma irradiated PM-355 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Fazal-ur-Rehman E-mail: fazalr@kfupm.edu.sa; Abu-Jarad, F.; Al-Jarallah, M.I.; Farhat, M

    2001-06-01

    Samples of Nuclear Track Detectors (PM-355) were exposed to high gamma doses from 1x10{sup 5} Gy (10 Mrad) up to 1.2x10{sup 6} Gy (120 Mrad) at an incremental dose of 1x10{sup 5} Gy (10 Mrad). The gamma source was a 9.03 PBq (244 kCi) Co-60 source used for sterilization of medical syringes. The bulk etch rate (V{sub b}) was measured for various high gamma doses by three different methods: 1--thickness change method; 2--mass change method; 3--fission track diametric method. The study gives a comparison and limitations of these three methods used for bulk etch rate measurements in the detectors as a function of high gamma doses. The track etch rate (V{sub t}) and the sensitivity (V) of the detector were also measured using the fission track diametric method. It was observed that V{sub b} increases with the increase of the gamma absorbed dose at a fixed etching time in each bulk etch measuring method. The bulk etch rate decreases exponentially with the etching time at a fixed gamma absorbed dose in all three methods. The thickness change and mass change methods have successfully been applied to measure V{sub b} at higher gamma doses up to 1.2x10{sup 6} Gy (120 Mrad). The bulk etch rate determined by the mass change and thickness change methods was almost the same at a certain gamma dose and etching time whereas it was quite low in the case of the fission track diametric method due to its limitations at higher doses. Also in this method it was not possible to measure the fission fragment track diameters at higher doses due to the quick disappearance of the fission tracks and therefore the V{sub b} could not be estimated at higher gamma doses.

  20. Effect of PbI{sub 2} deposition rate on two-step PVD/CVD all-vacuum prepared perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Ioakeimidis, Apostolos; Christodoulou, Christos; Lux-Steiner, Martha; Fostiropoulos, Konstantinos, E-mail: fostiropoulos@helmholtz-berlin.de

    2016-12-15

    In this work we fabricate all-vacuum processed methyl ammonium lead halide perovskite by a sequence of physical vapour deposition of PbI{sub 2} and chemical vapour deposition (CVD) of CH{sub 3}NH{sub 3}I under a static atmosphere. We demonstrate that for higher deposition rate the (001) planes of PbI{sub 2} film show a higher degree of alignment parallel to the sample's surface. From X-ray diffraction data of the resulted perovskite film we derive that the intercalation rate of CH{sub 3}NH{sub 3}I is fostered for PbI{sub 2} films with higher degree of (001) planes alignment. The stoichiometry of the produced perovskite film is also studied by Hard X-ray photoelectron spectroscopy measurements. Complete all-vacuum perovskite solar cells were fabricated on glass/ITO substrates coated by an ultra-thin (5 nm) Zn-phthalocyanine film as hole selective layer. A dependence of residual PbI{sub 2} on the solar cells performance is displayed, while photovoltaic devices with efficiency up to η=11.6% were achieved. - Graphical abstract: A two-step PVD/CVD processed perovskite film with the CVD intercalation rate of CH{sub 3}NCH{sub 3} molecules been fostered by increasing the PVD rate of PbI{sub 2} and prolonging the CVD time. - Highlights: • A simple PVD/CVD process for perovskite film production. • Increased PVD rate yields better alignment of the PbI{sub 2} (001) crystallite planes. • CH{sub 3}NH{sub 3}I intercalation process fostered by increased PbI{sub 2} PVD rate. • Stoichiometric CH{sub 3}NH{sub 3}PbI{sub 3} suitable as absorber in photovoltaic applications • Reduced PbI{sub 2} residue at the bottom of CH{sub 3}NH{sub 3}PbI{sub 3} improves device performance.

  1. Control in the Rate-Determining Step Provides a Promising Strategy To Develop New Catalysts for CO2 Hydrogenation: A Local Pair Natural Orbital Coupled Cluster Theory Study.

    Science.gov (United States)

    Mondal, Bhaskar; Neese, Frank; Ye, Shengfa

    2015-08-03

    The development of efficient catalysts with base metals for CO2 hydrogenation has always been a major thrust of interest. A series of experimental and theoretical work has revealed that the catalytic cycle typically involves two key steps, namely, base-promoted heterolytic H2 splitting and hydride transfer to CO2, either of which can be the rate-determining step (RDS) of the entire reaction. To explore the determining factor for the nature of RDS, we present herein a comparative mechanistic investigation on CO2 hydrogenation mediated by [M(H)(η(2)-H2)(PP3(Ph))](n+) (M = Fe(II), Ru(II), and Co(III); PP3(Ph) = tris(2-(diphenylphosphino)phenyl)phosphine) type complexes. In order to construct reliable free energy profiles, we used highly correlated wave function based ab initio methods of the coupled cluster type alongside the standard density functional theory. Our calculations demonstrate that the hydricity of the metal-hydride intermediate generated by H2 splitting dictates the nature of the RDS for the Fe(II) and Co(III) systems, while the RDS for the Ru(II) catalyst appears to be ambiguous. CO2 hydrogenation catalyzed by the Fe(II) complex that possesses moderate hydricity traverses an H2-splitting RDS, whereas the RDS for the high-hydricity Co(III) species is found to be the hydride transfer. Thus, our findings suggest that hydricity can be used as a practical guide in future catalyst design. Enhancing the electron-accepting ability of low-hydricity catalysts is likely to improve their catalytic performance, while increasing the electron-donating ability of high-hydricity complexes may speed up CO2 conversion. Moreover, we also established the active roles of base NEt3 in directing the heterolytic H2 splitting and assisting product release through the formation of an acid-base complex.

  2. A novel two-step optimization method for tandem and ovoid high-dose-rate brachytherapy treatment for locally advanced cervical cancer.

    Science.gov (United States)

    Sharma, Manju; Fields, Emma C; Todor, Dorin A

    2015-01-01

    To present a novel method allowing fast volumetric optimization of tandem and ovoid high-dose-rate treatments and to quantify its benefits. Twenty-seven CT-based treatment plans from 6 consecutive cervical cancer patients treated with four to five intracavitary tandem and ovoid insertions were used. Initial single-step optimized plans were manually optimized, approved, and delivered plans created with a goal to cover high-risk clinical target volume (HR-CTV) with D90 >90% and minimize rectum, bladder, and sigmoid D2cc. For the two-step optimized (TSO) plan, each single-step optimized plan was replanned adding a structure created from prescription isodose line to the existent physician delineated HR-CTV, rectum, bladder, and sigmoid. New, more rigorous dose-volume histogram constraints for the critical organs at risks (OARs) were used for the optimization. HR-CTV D90 and OAR D2ccs were evaluated in both plans. TSO plans had consistently smaller D2ccs for all three OARs while preserving HR-CTV D90. On plans with "excellent" CTV coverage, average D90 of 96% (91-102%), sigmoid, bladder, and rectum D2cc, respectively, reduced on average by 37% (16-73%), 28% (20-47%), and 27% (15-45%). Similar reductions were obtained on plans with "good" coverage, average D90 of 93% (90-99%). For plans with "inferior" coverage, average D90 of 81%, the coverage increased to 87% with concurrent D2cc reductions of 31%, 18%, and 11% for sigmoid, bladder, and rectum, respectively. The TSO can be added with minimal planning time increase but with the potential of dramatic and systematic reductions in OAR D2ccs and in some cases with concurrent increase in target dose coverage. These single-fraction modifications would be magnified over the course of four to five intracavitary insertions and may have real clinical implications in terms of decreasing both acute and late toxicities. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. Physiology of Aspergillus niger in Oxygen-Limited Continuous Cultures: Influence of Aeration, Carbon Source Concentration and Dilution Rate

    DEFF Research Database (Denmark)

    Diano, Audrey; Peeters, J.; Dynesen, Jens Østergaard

    2009-01-01

    In industrial production of enzymes using the filamentous fungus Aspergilhis niger supply of sufficient oxygen is often a limitation, resulting in the formation of by-products such as polyols. In order to identify the mechanisms behind formation of the different by-products we studied the effect...... of low oxygen availability, at different carbon source concentrations and at different specific growth rates, on the metabolism of A. niger, using continuous cultures. The results show that there is an increase in the production of tricarboxylic acid (TCA) cycle intermediates at low oxygen concentrations...

  4. Formation of hydrogen bonds precedes the rate-limiting formation of persistent structure in the folding of ACBP

    DEFF Research Database (Denmark)

    Teilum, K; Kragelund, B B; Knudsen, J

    2000-01-01

    A burst phase in the early folding of the four-helix two-state folder protein acyl-coenzyme A binding protein (ACBP) has been detected using quenched-flow in combination with site-specific NMR-detected hydrogen exchange. Several of the burst phase structures coincide with a structure consisting...... of eight conserved hydrophobic residues at the interface between the two N and C-terminal helices. Previous mutation studies have shown that the formation of this structure is rate limiting for the final folding of ACBP. The burst phase structures observed in ACBP are different from the previously reported...

  5. Influence of step complexity and presentation style on step performance of computerized emergency operating procedures

    Energy Technology Data Exchange (ETDEWEB)

    Xu Song [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China); Li Zhizhong [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: zzli@tsinghua.edu.cn; Song Fei; Luo Wei; Zhao Qianyi; Salvendy, Gavriel [Department of Industrial Engineering, Tsinghua University, Beijing 100084 (China)

    2009-02-15

    With the development of information technology, computerized emergency operating procedures (EOPs) are taking the place of paper-based ones. However, ergonomics issues of computerized EOPs have not been studied adequately since the industrial practice is quite limited yet. This study examined the influence of step complexity and presentation style of EOPs on step performance. A simulated computerized EOP system was developed in two presentation styles: Style A: one- and two-dimensional flowcharts combination; Style B: two-dimensional flowchart and success logic tree combination. Step complexity was quantified by a complexity measure model based on an entropy concept. Forty subjects participated in the experiment of EOP execution using the simulated system. The results of data analysis on the experiment data indicate that step complexity and presentation style could significantly influence step performance (both step error rate and operation time). Regression models were also developed. The regression analysis results imply that operation time of a step could be well predicted by step complexity while step error rate could only partly predicted by it. The result of a questionnaire investigation implies that step error rate was influenced not only by the operation task itself but also by other human factors. These findings may be useful for the design and assessment of computerized EOPs.

  6. Rated-voltage enhancement by fast-breaking of the fault current for a resistive superconducting fault current limiter component

    International Nuclear Information System (INIS)

    Park, C.-R.; Kim, M.-J.; Yu, S.-D.; Yim, S.-W.; Kim, H.-R.; Hyun, O.-B.

    2010-01-01

    Performance of a resistive superconducting fault current limiter (SFCL) component is usually limited by temperature rise associated with energy input by fault current application during a fault. Therefore, it is expected that short application of the fault current may enhance the power ratings of the component. This can be accomplished by a combination of a HTS component and a mechanical switch. The fast switch (FS) developed recently enables the fault duration to be as short as 1/2 cycle after a fault. Various second-generation (2G) high temperature superconductors (HTS) and YBCO thin films have been tested. The relation between the rated voltage V and the fault duration time t was found to be V 2 ∼ t -1 . Based upon the relation, we predict that when the FS break the fault current within 1/2 cycle after a fault, the amount of HTS components required to build an SFCL can be reduced by as much as about 60%, of that when breaking the fault current at three cycles.

  7. Increasing the Photoautotrophic Growth Rate of Synechocystis sp. PCC 6803 by Identifying the Limitations of Its Cultivation.

    Science.gov (United States)

    van Alphen, Pascal; Abedini Najafabadi, Hamed; Branco Dos Santos, Filipe; Hellingwerf, Klaas J

    2018-03-25

    Many conditions have to be optimized in order to be able to grow the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) for an extended period of time under physiologically well-defined and constant conditions. It is still poorly understood what limits growth of this organism in batch and continuous cultures in BG-11, the standard medium used to grow Synechocystis. Through a series of batch experiments in flasks and continuous mode experiments in advanced photobioreactors, it is shown that the limiting nutrient during batch cultivation is sulfate, the depletion of which leads to ROS formation and rapid bleaching of pigments after entry into stationary phase. In continuous mode, however, the limiting nutrient is iron. Optimizing these growth conditions resulted in a so far highest growth rate of 0.16 h -1 (4.3 h doubling time), which is significantly higher than the textbook value of 0.09 h -1 (8 h doubling time). An improved medium, BG-11 for prolonged cultivation (BG-11-PC) is introduced, that allows for controlled, extended cultivation of Synechocystis, under well-defined physiological conditions. The data present here have implications for mass-culturing of cyanobacteria. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Convergence of Numerical Sequences--A Commentary on "The Vice: Some Historically Inspired and Proof Generated Steps to Limits of Sequences" by R. P. Burn

    Science.gov (United States)

    Berge, Analia

    2006-01-01

    Burn (2005) proposes a "genetic approach" to teaching limits of numerical sequences. The article includes an explanation of the Method of Exhaustion, a generalization of this method, and a description of how this method was used for obtaining areas and lengths in the seventeenth century. The author uses these historical and mathematical analyses…

  9. Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit

    KAUST Repository

    Masih, Dilshad; Aly, Shawkat Mohammede; Alarousu, Erkki; Mohammed, Omar F.

    2015-01-01

    previously unattained detection limit of 1 × 10−12 M) and economical method for the determination of iodide. To fully understand the reaction mechanism responsible for the phosphorescence quenching process, we have employed cutting-edge time-resolved laser

  10. Astrophysical limitations to the identification of dark matter: Indirect neutrino signals vis-a-vis direct detection recoil rates

    International Nuclear Information System (INIS)

    Serpico, Pasquale D.; Bertone, Gianfranco

    2010-01-01

    A convincing identification of dark matter (DM) particles can probably be achieved only through a combined analysis of different detections strategies, which provides an effective way of removing degeneracies in the parameter space of DM models. In practice, however, this program is made complicated by the fact that different strategies depend on different physical quantities, or on the same quantities but in a different way, making the treatment of systematic errors rather tricky. We discuss here the uncertainties on the recoil rate in direct-detection experiments and on the muon rate induced by neutrinos from dark matter annihilations in the Sun, and we show that, contrarily to the local DM density or overall cross section scale, irreducible astrophysical uncertainties affect the two rates in a different fashion, therefore limiting our ability to reconstruct the parameters of the dark matter particles. By varying within their respective errors astrophysical parameters such as the escape velocity and the velocity dispersion of dark matter particles, we show that the uncertainty on the relative strength of the neutrino and direct-detection signal is as large as a factor of 2 for typical values of the parameters, but can be even larger in some circumstances.

  11. Age- and sex-specific reference limits for creatinine, cystatin C and the estimated glomerular filtration rate.

    Science.gov (United States)

    Hannemann, Anke; Friedrich, Nele; Dittmann, Kathleen; Spielhagen, Christin; Wallaschofski, Henri; Völzke, Henry; Rettig, Rainer; Endlich, Karlhans; Lendeckel, Uwe; Stracke, Sylvia; Nauck, Matthias

    2011-11-14

    Early detection of patients with chronic kidney disease is of great importance. This study developed reference limits for serum creatinine and serum cystatin C concentrations and for the estimated glomerular filtration rate (eGFR) in healthy subjects from the general population aged 25-65 years. This study defined a reference population including 985 subjects from the first follow-up of the Study of Health in Pomerania. Serum creatinine was measured with a modified kinetic Jaffé method. Serum cystatin C was measured with a nephelometric assay. The eGFR was calculated from serum creatinine according to the Cockcroft-Gault (eGFR(CG)) and the Modification of Diet in Renal Disease (eGFR(MDRD)) equation, respectively, as well as from serum cystatin C according to the formula by Larsson (eGFR(Larsson)). Non-parametric quantile regression was used to estimate the reference limits. For serum creatinine and serum cystatin C the 95th percentile and for eGFR(CG), eGFR(MDRD) and eGFR(Larsson) the 5th percentile were selected as reference limits. All data was weighted to reflect the age- and sex-structure of the German population in 2008. The reference limits for serum creatinine (men: 1.11-1.23 mg/dL; women: 0.93-1.00 mg/dL) and serum cystatin C levels (men: 0.92-1.04 mg/L; women: 0.84-1.02 mg/L) increased with advancing age. The reference limits for eGFR decreased with increasing age (eGFR(CG) men: 106.0-64.7 mL/min, women 84.4-57.9 mL/min; eGFR(MDRD) men: 82.5-62.2 mL/min/1.73 m², women 75.0-58.2 mL/min/1.73 m²; eGFR(Larsson) men: 85.5-72.9 mL/min, women 94.5-75.7 mL/min). This study presents age- and sex-specific reference limits for five measures of renal function based on quantile regression models.

  12. Why does the Y326I mutant of monoamine oxidase B decompose an endogenous amphetamine at a slower rate than the wild type enzyme? Reaction step elucidated by multiscale molecular simulations.

    Science.gov (United States)

    Pregeljc, Domen; Jug, Urška; Mavri, Janez; Stare, Jernej

    2018-02-07

    This work investigates the Y326I point mutation effect on the kinetics of oxidative deamination of phenylethylamine (PEA) catalyzed by the monoamine oxidase B (MAO B) enzyme. PEA is a neuromodulator capable of affecting the plasticity of the brain and is responsible for the mood enhancing effect caused by physical exercise. Due to a similar functionality, PEA is often regarded as an endogenous amphetamine. The rate limiting step of the deamination was simulated at the multiscale level, employing the Empirical Valence Bond approach for the quantum treatment of the involved valence states, whereas the environment (solvated protein) was represented with a classical force field. A comparison of the reaction free energy profiles delivered by simulation of the reaction in the wild type MAO B and its Y326I mutant yields an increase in the barrier by 1.06 kcal mol -1 upon mutation, corresponding to a roughly 6-fold decrease in the reaction rate. This is in excellent agreement with the experimental kinetic studies. Inspection of simulation trajectories reveals possible sources of the point mutation effect, namely vanishing favorable electrostatic interactions between PEA and a Tyr326 side chain and an increased amount of water molecules at the active site due to the replacement of tyrosine by a less spacious isoleucine residue, thereby increasing the dielectric shielding of the catalytic environment provided by the enzyme.

  13. Simplification of antiretroviral therapy: a necessary step in the public health response to HIV/AIDS in resource-limited settings.

    Science.gov (United States)

    Vitoria, Marco; Ford, Nathan; Doherty, Meg; Flexner, Charles

    2014-01-01

    The global scale-up of antiretroviral therapy (ART) over the past decade represents one of the great public health and human rights achievements of recent times. Moving from an individualized treatment approach to a simplified and standardized public health approach has been critical to ART scale-up, simplifying both prescribing practices and supply chain management. In terms of the latter, the risk of stock-outs can be reduced and simplified prescribing practices support task shifting of care to nursing and other non-physician clinicians; this strategy is critical to increase access to ART care in settings where physicians are limited in number. In order to support such simplification, successive World Health Organization guidelines for ART in resource-limited settings have aimed to reduce the number of recommended options for first-line ART in such settings. Future drug and regimen choices for resource-limited settings will likely be guided by the same principles that have led to the recommendation of a single preferred regimen and will favour drugs that have the following characteristics: minimal risk of failure, efficacy and tolerability, robustness and forgiveness, no overlapping resistance in treatment sequencing, convenience, affordability, and compatibility with anti-TB and anti-hepatitis treatments.

  14. Limited Margin Radiation Therapy for Children and Young Adults With Ewing Sarcoma Achieves High Rates of Local Tumor Control

    Energy Technology Data Exchange (ETDEWEB)

    Talleur, Aimee C.; Navid, Fariba [Department of Oncology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Spunt, Sheri L. [Department of Pediatrics, Stanford University School of Medicine, Stanford, California (United States); McCarville, M. Beth [Department of Diagnostic Imaging, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu, John; Mao, Shenghua [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Davidoff, Andrew M. [Department of Surgery, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Department of Surgery, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee (United States); Neel, Michael D. [Department of Surgery, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Krasin, Matthew J., E-mail: matthew.krasin@stjude.org [Department of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2016-09-01

    Purpose: To determine the rate of local failure using focal conformal, limited margin radiation therapy (RT) and dose escalation for tumors ≥8 cm (greatest dimension at diagnosis) in children and young adults with Ewing sarcoma (EWS). Methods and Materials: Eligible patients with EWS were treated on a phase 2 institutional trial of focal conformal, limited margin RT using conformal or intensity modulated techniques. The treatment volume incorporated a 1-cm constrained margin around the gross tumor. Unresected tumors, <8 cm at diagnosis, received a standard dose of 55.8 Gy and tumors ≥8 cm, an escalated dose to 64.8 Gy. Patients with microscopic residual disease after resection received adjuvant RT to 50.4 Gy. Adjuvant brachytherapy was permitted in selected patients. Results: Forty-five patients were enrolled: 26 with localized and 19 with metastatic disease. Median (range) age, tumor size, and follow-up were 13.0 years (2.9-24.7 years), 9.0 cm (2.4-17.0 cm), and 54.5 months (1.9-122.2 months), respectively. All patients received systemic chemotherapy. The median (range) RT dose for all patients was 56.1 Gy (45-65.5 Gy). Seventeen patients received adjuvant, 16 standard-dose, and 12 escalated-dose RT. Failures included 1 local, 10 distant, and 1 local/distant. The estimated 10-year cumulative incidence of local failure was 4.4% ± 3.1%, with no statistical difference seen between RT treatment groups and no local failures in the escalated-dose RT treatment group. Conclusions: Treatment with focal conformal, limited margin RT, including dose escalation for larger tumors, provides favorable local tumor control in EWS.

  15. Limited Margin Radiation Therapy for Children and Young Adults With Ewing Sarcoma Achieves High Rates of Local Tumor Control

    International Nuclear Information System (INIS)

    Talleur, Aimee C.; Navid, Fariba; Spunt, Sheri L.; McCarville, M. Beth; Wu, John; Mao, Shenghua; Davidoff, Andrew M.; Neel, Michael D.; Krasin, Matthew J.

    2016-01-01

    Purpose: To determine the rate of local failure using focal conformal, limited margin radiation therapy (RT) and dose escalation for tumors ≥8 cm (greatest dimension at diagnosis) in children and young adults with Ewing sarcoma (EWS). Methods and Materials: Eligible patients with EWS were treated on a phase 2 institutional trial of focal conformal, limited margin RT using conformal or intensity modulated techniques. The treatment volume incorporated a 1-cm constrained margin around the gross tumor. Unresected tumors, <8 cm at diagnosis, received a standard dose of 55.8 Gy and tumors ≥8 cm, an escalated dose to 64.8 Gy. Patients with microscopic residual disease after resection received adjuvant RT to 50.4 Gy. Adjuvant brachytherapy was permitted in selected patients. Results: Forty-five patients were enrolled: 26 with localized and 19 with metastatic disease. Median (range) age, tumor size, and follow-up were 13.0 years (2.9-24.7 years), 9.0 cm (2.4-17.0 cm), and 54.5 months (1.9-122.2 months), respectively. All patients received systemic chemotherapy. The median (range) RT dose for all patients was 56.1 Gy (45-65.5 Gy). Seventeen patients received adjuvant, 16 standard-dose, and 12 escalated-dose RT. Failures included 1 local, 10 distant, and 1 local/distant. The estimated 10-year cumulative incidence of local failure was 4.4% ± 3.1%, with no statistical difference seen between RT treatment groups and no local failures in the escalated-dose RT treatment group. Conclusions: Treatment with focal conformal, limited margin RT, including dose escalation for larger tumors, provides favorable local tumor control in EWS.

  16. Four-dimensional dose distributions of step-and-shoot IMRT delivered with real-time tumor tracking for patients with irregular breathing: Constant dose rate vs dose rate regulation

    International Nuclear Information System (INIS)

    Yang Xiaocheng; Han-Oh, Sarah; Gui Minzhi; Niu Ying; Yu, Cedric X.; Yi Byongyong

    2012-01-01

    Purpose: Dose-rate-regulated tracking (DRRT) is a tumor tracking strategy that programs the MLC to track the tumor under regular breathing and adapts to breathing irregularities during delivery using dose rate regulation. Constant-dose-rate tracking (CDRT) is a strategy that dynamically repositions the beam to account for intrafractional 3D target motion according to real-time information of target location obtained from an independent position monitoring system. The purpose of this study is to illustrate the differences in the effectiveness and delivery accuracy between these two tracking methods in the presence of breathing irregularities. Methods: Step-and-shoot IMRT plans optimized at a reference phase were extended to remaining phases to generate 10-phased 4D-IMRT plans using segment aperture morphing (SAM) algorithm, where both tumor displacement and deformation were considered. A SAM-based 4D plan has been demonstrated to provide better plan quality than plans not considering target deformation. However, delivering such a plan requires preprogramming of the MLC aperture sequence. Deliveries of the 4D plans using DRRT and CDRT tracking approaches were simulated assuming the breathing period is either shorter or longer than the planning day, for 4 IMRT cases: two lung and two pancreatic cases with maximum GTV centroid motion greater than 1 cm were selected. In DRRT, dose rate was regulated to speed up or slow down delivery as needed such that each planned segment is delivered at the planned breathing phase. In CDRT, MLC is separately controlled to follow the tumor motion, but dose rate was kept constant. In addition to breathing period change, effect of breathing amplitude variation on target and critical tissue dose distribution is also evaluated. Results: Delivery of preprogrammed 4D plans by the CDRT method resulted in an average of 5% increase in target dose and noticeable increase in organs at risk (OAR) dose when patient breathing is either 10% faster or

  17. Pushing the Limits: 3D Layer-by-Layer-Assembled Composites for Cathodes with 160 C Discharge Rates.

    Science.gov (United States)

    Mo, Runwei; Tung, Siu On; Lei, Zhengyu; Zhao, Guangyu; Sun, Kening; Kotov, Nicholas A

    2015-05-26

    Deficiencies of cathode materials severely limit cycling performance and discharge rates of Li batteries. The key problem is that cathode materials must combine multiple properties: high lithium ion intercalation capacity, electrical/ionic conductivity, porosity, and mechanical toughness. Some materials revealed promising characteristics in a subset of these properties, but attaining the entire set of often contrarian characteristics requires new methods of materials engineering. In this paper, we report high surface area 3D composite from reduced graphene oxide loaded with LiFePO4 (LFP) nanoparticles made by layer-by-layer assembly (LBL). High electrical conductivity of the LBL composite is combined with high ionic conductivity, toughness, and low impedance. As a result of such materials properties, reversible lithium storage capacity and Coulombic efficiency were as high as 148 mA h g(-1) and 99%, respectively, after 100 cycles at 1 C. Moreover, these composites enabled unusually high reversible charge-discharge rates up to 160 C with a storage capacity of 56 mA h g(-1), exceeding those of known LFP-based cathodes, some of them by several times while retaining high content of active cathode material. The study demonstrates that LBL-assembled composites enable resolution of difficult materials engineering tasks.

  18. Integrating Gene Correction in the Reprogramming and Transdifferentiation Processes: A One-Step Strategy to Overcome Stem Cell-Based Gene Therapy Limitations

    Directory of Open Access Journals (Sweden)

    Seo-Young Lee

    2016-01-01

    Full Text Available The recent advent of induced pluripotent stem cells (iPSCs and gene therapy tools has raised the possibility of autologous cell therapy for rare genetic diseases. However, cellular reprogramming is inefficient in certain diseases such as ataxia telangiectasia, Fanconi anemia, LIG4 syndrome, and fibrodysplasia ossificans progressiva syndrome, owing to interference of the disease-related genes. To overcome these therapeutic limitations, it is necessary to fundamentally correct the abnormal gene during or prior to the reprogramming process. In addition, as genetic etiology of Parkinson’s disease, it has been well known that induced neural stem cells (iNSCs were progressively depleted by LRRK2 gene mutation, LRRK2 (G2019S. Thus, to maintain the induced NSCs directly derived from PD patient cells harboring LRRK2 (G2019S, it would be ideal to simultaneously treat the LRRK2 (G2019S fibroblast during the process of TD. Therefore, simultaneous reprogramming (or TD and gene therapy would provide the solution for therapeutic limitation caused by vulnerability of reprogramming or TD, in addition to being suitable for general application to the generation of autologous cell-therapy products for patients with genetic defects, thereby obviating the need for the arduous processes currently required.

  19. Presteady-state and steady-state kinetic properties of human cytochrome c oxidase. Identification of rate-limiting steps in mammalian cytochrome c oxidase

    NARCIS (Netherlands)

    van Kuilenburg, A. B.; Gorren, A. C.; Dekker, H. L.; Nieboer, P.; van Gelder, B. F.; Muijsers, A. O.

    1992-01-01

    Human cytochrome c oxidase was purified in a fully active form from heart and skeletal muscle. The enzyme was selectively solubilised with octylglucoside and KCl from submitochondrial particles followed by ammonium sulphate fractionation. The presteady-state and steady-state kinetic properties of

  20. Long Term Sugarcane Crop Residue Retention Offers Limited Potential to Reduce Nitrogen Fertilizer Rates in Australian Wet Tropical Environments.

    Science.gov (United States)

    Meier, Elizabeth A; Thorburn, Peter J

    2016-01-01

    The warming of world climate systems is driving interest in the mitigation of greenhouse gas (GHG) emissions. In the agricultural sector, practices that mitigate GHG emissions include those that (1) reduce emissions [e.g., those that reduce nitrous oxide (N2O) emissions by avoiding excess nitrogen (N) fertilizer application], and (2) increase soil organic carbon (SOC) stocks (e.g., by retaining instead of burning crop residues). Sugarcane is a globally important crop that can have substantial inputs of N fertilizer and which produces large amounts of crop residues ('trash'). Management of N fertilizer and trash affects soil carbon and nitrogen cycling, and hence GHG emissions. Trash has historically been burned at harvest, but increasingly is being retained on the soil surface as a 'trash blanket' in many countries. The potential for trash retention to alter N fertilizer requirements and sequester SOC was investigated in this study. The APSIM model was calibrated with data from field and laboratory studies of trash decomposition in the wet tropics of northern Australia. APSIM was then validated against four independent data sets, before simulating location × soil × fertilizer × trash management scenarios. Soil carbon increased in trash blanketed soils relative to SOC in soils with burnt trash. However, further increases in SOC for the study region may be limited because the SOC in trash blanketed soils could be approaching equilibrium; future GHG mitigation efforts in this region should therefore focus on N fertilizer management. Simulated N fertilizer rates were able to be reduced from conventional rates regardless of trash management, because of low yield potential in the wet tropics. For crops subjected to continuous trash blanketing, there was substantial immobilization of N in decomposing trash so conventional N fertilizer rates were required for up to 24 years after trash blanketing commenced. After this period, there was potential to reduce N fertilizer

  1. Long term sugarcane crop residue retention offers limited potential to reduce nitrogen fertilizer rates in Australian wet tropical environments

    Directory of Open Access Journals (Sweden)

    Elizabeth Anne Meier

    2016-07-01

    Full Text Available The warming of world climate systems is driving interest in the mitigation of greenhouse gas (GHG emissions. In the agricultural sector, practices that mitigate GHG emissions include those that (1 reduce emissions (e.g. those that reduce nitrous oxide (N2O emissions by avoiding excess nitrogen (N fertilizer application, and (2 increase soil organic carbon (SOC stocks (e.g. by retaining instead of burning crop residues. Sugarcane is a globally important crop that can have substantial inputs of N fertilizer and which produces large amounts of crop residues (‘trash’. Management of N fertilizer and trash affects soil carbon and nitrogen cycling, and hence GHG emissions. Trash has historically been burned at harvest, but increasingly is being retained on the soil surface as a ‘trash blanket’ in many countries. The potential for trash retention to alter N fertilizer requirements and sequester SOC was investigated in this study. The APSIM model was calibrated with data from field and laboratory studies of trash decomposition in the wet tropics of northern Australia. APSIM was then validated against four independent data sets, before simulating location  soil  fertilizer  trash management scenarios. Soil carbon increased in trash blanketed soils relative to SOC in soils with burnt trash. However, further increases in SOC for the study region may be limited because the SOC in trash blanketed soils could be approaching equilibrium; future GHG mitigation efforts in this region should therefore focus on N fertilizer management. Simulated N fertilizer rates were able to be reduced from conventional rates regardless of trash management, because of low yield potential in the wet tropics. For crops subjected to continuous trash blanketing, there was substantial immobilization of N in decomposing trash so conventional N fertilizer rates were required for up to 24 yr after trash blanketing commenced. After this period, there was potential to

  2. 13 CFR 107.855 - Interest rate ceiling and limitations on fees charged to Small Businesses (“Cost of Money”).

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Interest rate ceiling and... § 107.855 Interest rate ceiling and limitations on fees charged to Small Businesses (“Cost of Money... weighted average interest rate you pay on your “qualified borrowings”. “Qualified borrowings” means your...

  3. Incremental artificial bee colony with local search to economic dispatch problem with ramp rate limits and prohibited operating zones

    International Nuclear Information System (INIS)

    Özyön, Serdar; Aydin, Doğan

    2013-01-01

    Highlights: ► Prohibited operating zone economic dispatch problem has been solved by IABC-LS. ► The losses used in the solution of the problem have been computed by B-loss matrix. ► IABC-LS method has been applied to three test systems in literature. ► The values obtained by IABC and IABC-LS are better than the results in literature. - Abstract: In this study, prohibited operating zone economic power dispatch problem which considers ramp rate limit, has been solved by incremental artificial bee colony algorithm (IABC) and incremental artificial bee colony algorithm with local search (IABC-LS) methods. The transmission line losses used in the solution of the problem have been computed by B-loss matrix. IABC, IABC-LS methods have been applied to three different test systems in literature which consist of 6, 15 and 40 generators. The attained optimum solution values have been compared with the optimum results in literature and have been discussed.

  4. A Comprehensive Prediction Model of Hydraulic Extended-Reach Limit Considering the Allowable Range of Drilling Fluid Flow Rate in Horizontal Drilling.

    Science.gov (United States)

    Li, Xin; Gao, Deli; Chen, Xuyue

    2017-06-08

    Hydraulic extended-reach limit (HERL) model of horizontal extended-reach well (ERW) can predict the maximum measured depth (MMD) of the horizontal ERW. The HERL refers to the well's MMD when drilling fluid cannot be normally circulated by drilling pump. Previous model analyzed the following two constraint conditions, drilling pump rated pressure and rated power. However, effects of the allowable range of drilling fluid flow rate (Q min  ≤ Q ≤ Q max ) were not considered. In this study, three cases of HERL model are proposed according to the relationship between allowable range of drilling fluid flow rate and rated flow rate of drilling pump (Q r ). A horizontal ERW is analyzed to predict its HERL, especially its horizontal-section limit (L h ). Results show that when Q min  ≤ Q r  ≤ Q max (Case I), L h depends both on horizontal-section limit based on rated pump pressure (L h1 ) and horizontal-section limit based on rated pump power (L h2 ); when Q min  drilling fluid flow rate, while L h2 keeps decreasing as the drilling fluid flow rate increases. The comprehensive model provides a more accurate prediction on HERL.

  5. PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Vayner, Andrey; Wright, Shelley A. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Do, Tuan [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Larkin, James E. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Armus, Lee [Spitzer Science Center, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Gallagher, S. C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada)

    2016-04-10

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ∼ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ∼0.″2 (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (z{sub Hα} = 2.182) and SDSS J0925+0655 (z{sub Hα} = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M{sub ⊙} yr{sup −1} originating from a compact region that is kinematically offset by 290–350 km s{sup −1}. For SDSS J0925+0655 we infer a SFR of 29 M{sub ⊙} yr{sup −1} distributed over three clumps that are spatially offset by ∼7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M{sub ⊙} yr{sup −1} kpc{sup −2}. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M{sub ⊙} yr{sup −1} kpc{sup −2}. These IFS observations indicate that while the central black hole is accreting mass at 10%–40% of the Eddington rate, if

  6. Tenax extraction for exploring rate-limiting factors in methyl-β-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy soil

    International Nuclear Information System (INIS)

    Sun, Mingming; Ye, Mao; Hu, Feng; Li, Huixin; Teng, Ying; Luo, Yongming; Jiang, Xin; Kengara, Fredrick Orori

    2014-01-01

    Highlights: • Enhanced anaerobic bioremediation of a red paddy soil polluted with PAHs. • 1% (w/w) methyl-β-cyclodextrin (MCD) and 20 mM nitrate addition acted as solubility-enhancing agent and electron acceptor respectively. • Tenax extraction and a first-three-compartment modeling were applicable to explore the rate-limiting factors in the biodegradation. • Lack of PAH-degraders hindered biodegradation in control and MCD addition treatments. • Inadequate bioaccessible PAHs was vital rate-limiting factor in nitrate addition treatments. -- Abstract: The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information on what is the rate-limiting factor in bioremediation process is of vital importance in the decision in what measures can be taken to assist the biodegradation efficacy. In the present study, four different microcosms were set to study the effect of methyl-β-cyclodextrin (MCD) and nitrate addition (N) on PAHs biodegradation under anaerobic conditions in a red paddy soil. Meanwhile, sequential Tenax extraction combined with a first-three-compartment model was employed to evaluate the rate-limiting factors in MCD enhanced anaerobic biodegradation of PAHs. Microcosms with both 1% (w/w) MCD and 20 mM N addition produced maximum biodegradation of total PAHs of up to 61.7%. It appears rate-limiting factors vary with microcosms: low activity of degrading microorganisms is the vital rate-limiting factor for control and MCD addition treatments (CK and M treatments); and lack of bioaccessible PAHs is the main rate-limiting factor for nitrate addition treatments (N and MN treatments). These results have practical implications for site risk assessment and cleanup strategies

  7. Tenax extraction for exploring rate-limiting factors in methyl-β-cyclodextrin enhanced anaerobic biodegradation of PAHs under denitrifying conditions in a red paddy soil

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Mingming, E-mail: sunmingming@njau.edu.cn [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Key Laboratory of Soil Environmental and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Ye, Mao [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Hu, Feng, E-mail: fenghu@njau.edu.cn [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Li, Huixin [Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Teng, Ying [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Luo, Yongming [Yantai Institute of Costal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Jiang, Xin [State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Kengara, Fredrick Orori [Department of Chemistry, Maseno University, Private Bag, Maseno 40105 (Kenya)

    2014-01-15

    Highlights: • Enhanced anaerobic bioremediation of a red paddy soil polluted with PAHs. • 1% (w/w) methyl-β-cyclodextrin (MCD) and 20 mM nitrate addition acted as solubility-enhancing agent and electron acceptor respectively. • Tenax extraction and a first-three-compartment modeling were applicable to explore the rate-limiting factors in the biodegradation. • Lack of PAH-degraders hindered biodegradation in control and MCD addition treatments. • Inadequate bioaccessible PAHs was vital rate-limiting factor in nitrate addition treatments. -- Abstract: The effectiveness of anaerobic bioremediation systems for PAH-contaminated soil may be constrained by low contaminants bioaccessibility due to limited aqueous solubility and lack of suitable electron acceptors. Information on what is the rate-limiting factor in bioremediation process is of vital importance in the decision in what measures can be taken to assist the biodegradation efficacy. In the present study, four different microcosms were set to study the effect of methyl-β-cyclodextrin (MCD) and nitrate addition (N) on PAHs biodegradation under anaerobic conditions in a red paddy soil. Meanwhile, sequential Tenax extraction combined with a first-three-compartment model was employed to evaluate the rate-limiting factors in MCD enhanced anaerobic biodegradation of PAHs. Microcosms with both 1% (w/w) MCD and 20 mM N addition produced maximum biodegradation of total PAHs of up to 61.7%. It appears rate-limiting factors vary with microcosms: low activity of degrading microorganisms is the vital rate-limiting factor for control and MCD addition treatments (CK and M treatments); and lack of bioaccessible PAHs is the main rate-limiting factor for nitrate addition treatments (N and MN treatments). These results have practical implications for site risk assessment and cleanup strategies.

  8. SPAR-H Step-by-Step Guidance

    International Nuclear Information System (INIS)

    Galyean, W.J.; Whaley, A.M.; Kelly, D.L.; Boring, R.L.

    2011-01-01

    This guide provides step-by-step guidance on the use of the SPAR-H method for quantifying Human Failure Events (HFEs). This guide is intended to be used with the worksheets provided in: 'The SPAR-H Human Reliability Analysis Method,' NUREG/CR-6883, dated August 2005. Each step in the process of producing a Human Error Probability (HEP) is discussed. These steps are: Step-1, Categorizing the HFE as Diagnosis and/or Action; Step-2, Rate the Performance Shaping Factors; Step-3, Calculate PSF-Modified HEP; Step-4, Accounting for Dependence, and; Step-5, Minimum Value Cutoff. The discussions on dependence are extensive and include an appendix that describes insights obtained from the psychology literature.

  9. SPAR-H Step-by-Step Guidance

    Energy Technology Data Exchange (ETDEWEB)

    W. J. Galyean; A. M. Whaley; D. L. Kelly; R. L. Boring

    2011-05-01

    This guide provides step-by-step guidance on the use of the SPAR-H method for quantifying Human Failure Events (HFEs). This guide is intended to be used with the worksheets provided in: 'The SPAR-H Human Reliability Analysis Method,' NUREG/CR-6883, dated August 2005. Each step in the process of producing a Human Error Probability (HEP) is discussed. These steps are: Step-1, Categorizing the HFE as Diagnosis and/or Action; Step-2, Rate the Performance Shaping Factors; Step-3, Calculate PSF-Modified HEP; Step-4, Accounting for Dependence, and; Step-5, Minimum Value Cutoff. The discussions on dependence are extensive and include an appendix that describes insights obtained from the psychology literature.

  10. The formation of a native-like structure containing eight conserved hydrophobic residues is rate limiting in two-state protein folding of ACBP

    DEFF Research Database (Denmark)

    Kragelund, Birthe Brandt; Osmark, Peter; Neergaard, Thomas B.

    1999-01-01

    The acyl-coenzyme A-binding proteins (ACBPs) contain 26 highly conserved sequence positions. The majority of these have been mutated in the bovine protein, and their influence on the rate of two-state folding and unfolding has been measured. The results identify eight sequence positions, out of 24...... probed, that are critical for fast productive folding. The residues are all hydrophobic and located in the interface between the N- and C-terminal helices. The results suggest that one specific site dominated by conserved hydrophobic residues forms the structure of the productive rate-determining folding...... step and that a sequential framework model can describe the protein folding reaction....

  11. Rate-limiting reaction in papain action as derived from the reaction of the enzyme with chloroacetic acid

    NARCIS (Netherlands)

    Sluyterman, L.A.A.E.

    1968-01-01

    Chloroacetic acid reacts with the essential thiol group of papain (EC 3.4.4.10) and inactivates the enzyme. The rate of inactivation, k, at pH 6.0, 25°, was determined in the absence and presence of the substrates benzoylarginine ethyl ester (BAEE) and benzoylglycine ethyl ester (BGEE). The rate was

  12. Effect of strain rate on sooting limits in counterflow diffusion flames of gaseous hydrocarbon fuels: Sooting temperature index and sooting sensitivity index

    KAUST Repository

    Wang, Yu

    2014-05-01

    The effect of the strain rate on the sooting limits in counterflow diffusion flames was investigated in various gaseous hydrocarbon fuels by varying the nitrogen dilution in the fuel and oxidizer streams. The sooting limit was defined as the critical fuel and oxygen mole fraction at which soot started to appear in the elastic light scattering signal. The sooting region for normal alkane fuels at a specified strain rate, in terms of the fuel and oxygen mole fraction, expanded as the number of carbon atoms increased. The alkene fuels (ethylene, propene) tested had a higher propensity for sooting as compared with alkane fuels with the same carbon numbers (ethane, propane). Branched iso-butane had a higher propensity for sooting than did n-butane. An increase in the strain rate reduced the tendency for sooting in all the fuels tested. The sensitivity of the sooting limit to the strain rate was more pronounced for less sooting fuels. When plotted in terms of calculated flame temperature, the critical oxygen mole fraction exhibited an Arrhenius form under sooting limit conditions, which can be utilized to significantly reduce the effort required to determine sooting limits at different strain rates. We found that the limiting temperatures of soot formation flames are viable sooting metrics for quantitatively rating the sooting tendency of various fuels, based on comparisons with threshold soot index and normalized smoke point data. We also introduce a sooting temperature index and a sooting sensitivity index, two quantitative measures to describe sooting propensity and its dependence on strain rate. © 2013 The Combustion Institute.

  13. A Method for Increasing the Operating Limit Capacity of Wind Farms Using Battery Energy Storage Systems with Rate of Change of Frequency

    Directory of Open Access Journals (Sweden)

    Dae-Hee Son

    2018-03-01

    Full Text Available In this paper, the appropriate rated power of battery energy storage system (BESS and the operating limit capacity of wind farms are determined considering power system stability, and novel output control methods of BESS and wind turbines are proposed. The rated power of BESS is determined by correlation with the kinetic energy that can be released from wind turbines and synchronous generators when a disturbance occurs in the power system. After the appropriate rated power of BESS is determined, a novel control scheme for quickly responding to disturbances should be applied to BESS. It is important to compensate the insufficient power difference between demand and supply more quickly after a disturbance, and for this purpose, BESS output is controlled using the rate of change of frequency (ROCOF. Generally, BESS output is controlled by the frequency droop control (FDC, however if ROCOF falls below the threshold, BESS output increases sharply. Under this control for BESS, the power system’s stability can be improved and the operating limit capacity of wind farms can be increased. The operating limit capacity is determined as the smaller of technical limit and dynamic limit capacity. The technical limit capacity is calculated by the difference between the maximum power of the generators connected to the power system and the magnitude of loads, and the dynamic limit capacity is determined by considering dynamic stability of a power system frequency when the wind turbines drop out from a power system. Output of the dynamic model developed for wind turbine is based on the operating limit capacity and is controlled by blade pitch angle. To validate the effectiveness of the proposed control method, different case studies are conducted, with simulations for BESS and wind turbine using Power System Simulation for Engineering (PSS/E.

  14. [Hydraulic limitation on photosynthetic rate of old Populus simonii trees in sandy soil of north Shaanxi Province].

    Science.gov (United States)

    Zuo, Li-Xiang; Li, Yang-Yang; Chen, Jia-Cun

    2014-06-01

    'Old and dwarf trees' on the loess plateau region mainly occurred among mature trees rather than among small trees. To elucidate the mechanism of tree age on 'old and dwarf trees' formation, taking Populus simonii, a tree species that accounted for the largest portion of 'old and dwarf trees' on the loess plateau, as an example, the growth, photosynthesis and hydraulic traits of P. simonii trees with different ages (young: 13-15 years, mid-aged: 31-34 years, and old: 49-54 years) were measured. The results showed that the dieback length increased, and net photosynthetic rate, stomatal conductance, transpiration rate, and whole plant hydraulic conductance decreased significantly with the increasing tree age. Both net photosynthetic rate and stomatal conductance measured at different dates were significantly and positively related to the whole plant hydraulic conductance, suggesting that the decreasing photosynthetic rate of old trees was possibly caused by the declined hydraulic conductance. Although the resistance to cavitation in stems and leaves was stronger in old trees than in young and mid-aged trees, there were no differences in midday native stem embolization degree and leaf hydraulic conductance based on the vulnerability curve estimation, suggesting that the increased hydraulic resistance of the soil-root system is probably the most important reason for decreasing the whole plant hydraulic conductance of old trees.

  15. Influence of nature, concentration and pH of buffer acid-base system on rate determining step of the electrochemiluminescence of Ru(bpy){sub 3} {sup 2+} with tertiary aliphatic amines

    Energy Technology Data Exchange (ETDEWEB)

    Pastore, Paolo [Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova (Italy)]. E-mail: paolo.pastore@unipd.it; Badocco, Denis [Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova (Italy); Zanon, Francesco [Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova (Italy)

    2006-07-28

    The electrogenerated chemiluminescence (ECL) of Ru(bpy){sub 3} {sup 2+} (bpy 2,2'-bipyridyl) with tertiary aliphatic amines as co-reactants, was theoretically and experimentally studied as a function of the pre-equilibria involved in the ammonium proton lost and in relation to the nature of the rate determining step. Transient potential steps were used with a 3-mm glassy carbon disk electrode or carbon fiber ultramicroelectrodes array to investigate emission behavior in a variety of aqueous solution types, containing phosphate, tartrate and phthalate acid-base systems at differing pH values. The emission of Ru(bpy){sub 3} {sup 2+} resulting from the reaction with n-tripropylamine (TPrA), tri-isobutylamine (TisoBuA), n-tributylamine (TBuA), methyl-di-n-propylamine (MeDPrA) and triethylamine (TEtA) in varying acid-base media was interpreted on the basis of the quoted pre-equilibria, ammonium pK {sub a} being known. The nature of the rate determining steps changes depending on pH. Above pH {approx} 5 the amine neutral radical formation is the rate determining step and, is independent of pH with rate constant close to 10{sup 3} s{sup -1}; below pH {approx} 5 the rate determining step becomes the deprotonation of the ammonium ion, operated by different bases present in solution. Different amines in the same acid-base system showed analogous ECL behavior, conditioned by the chosen acid base system. A single amine in different acid-base systems showed different kinetic behaviors, due to the dissociation constants of the chosen buffers. The concentration of the acid-base system also played an important role and influenced emission intensity and shape. ECL emission were simulated by finite difference methods, implementing a previously proposed mechanism by including the relevant pre-equilibria. Simulation may also give estimates of the pK {sub a} values of the ammonium ions. An ion pair formation between R{sub 3}N{center_dot} {sup +} and the mostly charged species

  16. Influence of nature, concentration and pH of buffer acid-base system on rate determining step of the electrochemiluminescence of Ru(bpy)32+ with tertiary aliphatic amines

    International Nuclear Information System (INIS)

    Pastore, Paolo; Badocco, Denis; Zanon, Francesco

    2006-01-01

    The electrogenerated chemiluminescence (ECL) of Ru(bpy) 3 2+ (bpy 2,2'-bipyridyl) with tertiary aliphatic amines as co-reactants, was theoretically and experimentally studied as a function of the pre-equilibria involved in the ammonium proton lost and in relation to the nature of the rate determining step. Transient potential steps were used with a 3-mm glassy carbon disk electrode or carbon fiber ultramicroelectrodes array to investigate emission behavior in a variety of aqueous solution types, containing phosphate, tartrate and phthalate acid-base systems at differing pH values. The emission of Ru(bpy) 3 2+ resulting from the reaction with n-tripropylamine (TPrA), tri-isobutylamine (TisoBuA), n-tributylamine (TBuA), methyl-di-n-propylamine (MeDPrA) and triethylamine (TEtA) in varying acid-base media was interpreted on the basis of the quoted pre-equilibria, ammonium pK a being known. The nature of the rate determining steps changes depending on pH. Above pH ∼ 5 the amine neutral radical formation is the rate determining step and, is independent of pH with rate constant close to 10 3 s -1 ; below pH ∼ 5 the rate determining step becomes the deprotonation of the ammonium ion, operated by different bases present in solution. Different amines in the same acid-base system showed analogous ECL behavior, conditioned by the chosen acid base system. A single amine in different acid-base systems showed different kinetic behaviors, due to the dissociation constants of the chosen buffers. The concentration of the acid-base system also played an important role and influenced emission intensity and shape. ECL emission were simulated by finite difference methods, implementing a previously proposed mechanism by including the relevant pre-equilibria. Simulation may also give estimates of the pK a values of the ammonium ions. An ion pair formation between R 3 N· + and the mostly charged species present in solution is hypothesized to explain the contradictory experimental

  17. The bounded proof property via step algebras and step frames

    NARCIS (Netherlands)

    Bezhanishvili, N.; Ghilardi, Silvio

    2013-01-01

    We develop a semantic criterion for a specific rule-based calculus Ax axiomatizing a given logic L to have the so-called bounded proof property. This property is a kind of an analytic subformula property limiting the proof search space. Our main tools are one-step frames and one-step algebras. These

  18. Radionuclide mass transfer rates from a pinhole in a waste container for an inventory-limited and a constant concentration source

    International Nuclear Information System (INIS)

    LeNeveu, D.M.

    1996-03-01

    Analytical solutions for transient and steady state diffusive mass transfer rates from a pinhole in a waste container are developed for constant concentration and inventory-limited source conditions. Mass transport in three media are considered, inside the pinhole (medium 2), outside the container (medium 3) and inside the container (medium 1). Simple equations are developed for radionuclide mass transfer rates from a pinhole. It is shown that the medium with the largest mass transfer resistance need only be considered to provide a conservative estimate of mass transfer rates. (author) 11 refs., 3 figs

  19. Direct measurements of damping rates and stability limits for low frequency MHD modes and Alfven Eigenmodes in the JET tokamak

    International Nuclear Information System (INIS)

    Fasoli, A.F.; Testa, D.; Jaun, A.; Sharapov, S.; Gormezano, C.

    2001-01-01

    The linear stability properties of global modes that can be driven by resonant energetic particles or by the bulk plasma are studied using an external excitation method based on the JET saddle coil antennas. Low toroidal mode number, stable plasma modes are driven by the saddle coils and detected by magnetic probes to measure their structure, frequency and damping rate, both in the Alfven Eigenmode (AE) frequency range and in the low frequency Magneto-Hydro-Dynamic (MHD) range. For AEs, the dominant damping mechanisms are identified for different plasma conditions of relevance for reactors. Spectra and damping rates of low frequency MHD modes that are localized at the foot of the internal transport barrier and can affect the plasma performance in advanced tokamak scenarios have been directly measured for the first time. This gives the possibility of monitoring in real time the approach to the instability boundary. (author)

  20. Development of slew-rate-limited time-over-threshold (ToT) ASIC for a multi-channel silicon-based ion detector

    Science.gov (United States)

    Uenomachi, M.; Orita, T.; Shimazoe, K.; Takahashi, H.; Ikeda, H.; Tsujita, K.; Sekiba, D.

    2018-01-01

    High-resolution Elastic Recoil Detection Analysis (HERDA), which consists of a 90o sector magnetic spectrometer and a position-sensitive detector (PSD), is a method of quantitative hydrogen analysis. In order to increase sensitivity, a HERDA system using a multi-channel silicon-based ion detector has been developed. Here, as a parallel and fast readout circuit from a multi-channel silicon-based ion detector, a slew-rate-limited time-over-threshold (ToT) application-specific integrated circuit (ASIC) was designed, and a new slew-rate-limited ToT method is proposed. The designed ASIC has 48 channels and each channel consists of a preamplifier, a slew-rate-limited shaping amplifier, which makes ToT response linear, and a comparator. The measured equivalent noise charges (ENCs) of the preamplifier, the shaper, and the ToT on no detector capacitance were 253±21, 343±46, and 560±56 electrons RMS, respectively. The spectra from a 241Am source measured using a slew-rate-limited ToT ASIC are also reported.

  1. Influence of the quenching rate and step-wise cooling temperatures on microstructural and tensile properties of PER72 ® Ni-based superalloy

    Directory of Open Access Journals (Sweden)

    Le Baillif Paul

    2014-01-01

    Full Text Available The PER72® grade is used as a wrought engine turbine disk, which is a critical high temperature component. During the heat treatment process, residual stresses are generated during the quench, which may lead to irreversible damages on the workpiece. The aim of this study is to better understand the mechanisms involved in the residual stress generation. Therefore, the influence of quenching conditions on the high temperature tensile properties and the multi-scale microstructure evolutions are investigated after cooling. PER72® specimens are annealed above the solvus temperature, directly on the servo-hydraulic testing machine. Three quenching rates are used: 30 ∘C/min, 120 ∘C/min, and 300 ∘C/min. For each condition, the cooling is interrupted at 1000 ∘C, 850 ∘C, 600 ∘C and 20 ∘C to perform isothermal tensile test. Specimens are post-mortem analysed. On one hand the fracture surface is investigated using SEM. On the other hand the microstructure evolution was observed and quantified at different scales using SEM directly on the bulk or after the chemical extraction of precipitation. The precipitation size and volume fraction statistics, X-Ray diffraction for the crystallography and composition of the different phases are investigated. It was shown that the testing temperature does not significantly influence the γ′ distribution of particles. Conversely, the γ′ precipitation is strongly influenced by the cooling rate. Notably, the average size, the distance between particles as well as the number density of γ′ precipitates are significantly modified by the cooling rate. Changes in tensile properties are related to microstructural.

  2. Application of stepping motor

    International Nuclear Information System (INIS)

    1980-10-01

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  3. One-step argon/nitrogen binary plasma jet irradiation of Li4Ti5O12 for stable high-rate lithium ion battery anodes

    Science.gov (United States)

    Lan, Chun-Kai; Chuang, Shang-I.; Bao, Qi; Liao, Yen-Ting; Duh, Jenq-Gong

    2015-02-01

    Atmospheric pressure Ar/N2 binary plasma jet irradiation has been introduced into the manufacturing process of lithium ions batteries as a facile, green and scalable post-fabrication treatment approach, which enhanced significantly the high-rate anode performance of lithium titanate (Li4Ti5O12). Main emission lines in Ar/N2 plasma measured by optical emission spectroscopy reveal that the dominant excited high-energy species in Ar/N2 plasma are N2*, N2+, N∗ and Ar∗. Sufficient oxygen vacancies have been evidenced by high resolution X-ray photoelectron spectroscopy analysis and Raman spectra. Nitrogen doping has been achieved simultaneously by the surface reaction between pristine Li4Ti5O12 particles and chemically reactive plasma species such as N∗ and N2+. The variety of Li4Ti5O12 particles on the surface of electrodes after different plasma processing time has been examined by grazing incident X-Ray diffraction. Electrochemical impedance spectra (EIS) confirm that the Ar/N2 atmospheric plasma treatment facilitates Li+ ions diffusion and reduces the internal charge-transfer resistance. The as-prepared Li4Ti5O12 anodes exhibit a superior capacity (132 mAh g-1) and excellent stability with almost no capacity decay over 100 cycles under a high C rate (10C).

  4. Overcoming time scale and finite size limitations to compute nucleation rates from small scale well tempered metadynamics simulations

    Science.gov (United States)

    Salvalaglio, Matteo; Tiwary, Pratyush; Maggioni, Giovanni Maria; Mazzotti, Marco; Parrinello, Michele

    2016-12-01

    Condensation of a liquid droplet from a supersaturated vapour phase is initiated by a prototypical nucleation event. As such it is challenging to compute its rate from atomistic molecular dynamics simulations. In fact at realistic supersaturation conditions condensation occurs on time scales that far exceed what can be reached with conventional molecular dynamics methods. Another known problem in this context is the distortion of the free energy profile associated to nucleation due to the small, finite size of typical simulation boxes. In this work the problem of time scale is addressed with a recently developed enhanced sampling method while contextually correcting for finite size effects. We demonstrate our approach by studying the condensation of argon, and showing that characteristic nucleation times of the order of magnitude of hours can be reliably calculated. Nucleation rates spanning a range of 10 orders of magnitude are computed at moderate supersaturation levels, thus bridging the gap between what standard molecular dynamics simulations can do and real physical systems.

  5. Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction.

    Science.gov (United States)

    Kim, Minkyung; Lee, Seongsu; Kang, Byoungwoo

    2016-03-01

    Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO 4 F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g -1 at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, ≈120 mAh g -1 at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO 4 F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO 4 F can achieve high power capability comparable to LiFePO 4 and much higher energy density (≈521 Wh g -1 at 20 C-rate) than LiFePO 4 even without nanostructured particles. LiVPO 4 F can be a real substitute of LiFePO 4.

  6. Effects of walking speed on the step-by-step control of step width.

    Science.gov (United States)

    Stimpson, Katy H; Heitkamp, Lauren N; Horne, Joscelyn S; Dean, Jesse C

    2018-02-08

    Young, healthy adults walking at typical preferred speeds use step-by-step adjustments of step width to appropriately redirect their center of mass motion and ensure mediolateral stability. However, it is presently unclear whether this control strategy is retained when walking at the slower speeds preferred by many clinical populations. We investigated whether the typical stabilization strategy is influenced by walking speed. Twelve young, neurologically intact participants walked on a treadmill at a range of prescribed speeds (0.2-1.2 m/s). The mediolateral stabilization strategy was quantified as the proportion of step width variance predicted by the mechanical state of the pelvis throughout a step (calculated as R 2 magnitude from a multiple linear regression). Our ability to accurately predict the upcoming step width increased over the course of a step. The strength of the relationship between step width and pelvis mechanics at the start of a step was reduced at slower speeds. However, these speed-dependent differences largely disappeared by the end of a step, other than at the slowest walking speed (0.2 m/s). These results suggest that mechanics-dependent adjustments in step width are a consistent component of healthy gait across speeds and contexts. However, slower walking speeds may ease this control by allowing mediolateral repositioning of the swing leg to occur later in a step, thus encouraging slower walking among clinical populations with limited sensorimotor control. Published by Elsevier Ltd.

  7. Heart rate variability at limiting stationarity: evidence of neuro-cardiac control mechanisms operating at ultra-low frequencies

    International Nuclear Information System (INIS)

    Fisher, A C; Groves, D; Eleuteri, A; Mesum, P; Patterson, D; Taggart, P

    2014-01-01

    This study considers the linkage of exogenously stimulated emotional stress with the neurogenic regulation of heart rate operating at very low frequencies. The objectives were three-fold: to consider the present evidence that such a linkage exists as a primary phenomenon; to compare the potential of a frequency-domain method and a time-domain method in revealing this phenomenon by characterizing heart rate variability (HRV) at frequencies of [0.0005…0.4] Hz and to design, implement and report a physiological experiment in which alternating periods of exposure to bland and high valence visual stimuli might reveal this phenomenon. A methodical challenge was to optimize the length of exposure to the stimulus such that subjects did not have time to habituate to stimuli, whilst acquiring sufficient data (heart beats) such that the ultra-low frequency (ULF) components of HRV could be described. With exposure times set to approximately 5 min, during which time the strength of the stimulus and the corresponding evoked response were considered stationary, the lowest HRV frequency component that could be characterized was 0.003 Hz. In trials with parametrically defined test data, the time-domain method based on the Ornstein–Uhlenbeck Gaussian process (OU-GP) was shown to be better than the frequency-domain method in describing the ULF components of the HRV. In an experimental cohort of 16 subjects, analysis using the OU-GP revealed evidence of cardiac regulatory mechanisms influenced by emotional valence operating in the bandwidth (ULF*) [0.002…0.01] Hz. (paper)

  8. SPAR-H Step-by-Step Guidance

    Energy Technology Data Exchange (ETDEWEB)

    April M. Whaley; Dana L. Kelly; Ronald L. Boring; William J. Galyean

    2012-06-01

    Step-by-step guidance was developed recently at Idaho National Laboratory for the US Nuclear Regulatory Commission on the use of the Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) method for quantifying Human Failure Events (HFEs). This work was done to address SPAR-H user needs, specifically requests for additional guidance on the proper application of various aspects of the methodology. This paper overviews the steps of the SPAR-H analysis process and highlights some of the most important insights gained during the development of the step-by-step directions. This supplemental guidance for analysts is applicable when plant-specific information is available, and goes beyond the general guidance provided in existing SPAR-H documentation. The steps highlighted in this paper are: Step-1, Categorizing the HFE as Diagnosis and/or Action; Step-2, Rate the Performance Shaping Factors; Step-3, Calculate PSF-Modified HEP; Step-4, Accounting for Dependence, and; Step-5, Minimum Value Cutoff.

  9. Step out - Step in Sequencing Games

    NARCIS (Netherlands)

    Musegaas, M.; Borm, P.E.M.; Quant, M.

    2014-01-01

    In this paper a new class of relaxed sequencing games is introduced: the class of Step out - Step in sequencing games. In this relaxation any player within a coalition is allowed to step out from his position in the processing order and to step in at any position later in the processing order.

  10. Step out-step in sequencing games

    NARCIS (Netherlands)

    Musegaas, Marieke; Borm, Peter; Quant, Marieke

    2015-01-01

    In this paper a new class of relaxed sequencing games is introduced: the class of Step out–Step in sequencing games. In this relaxation any player within a coalition is allowed to step out from his position in the processing order and to step in at any position later in the processing order. First,

  11. Effect of High Phytase Inclusion Rates on Performance of Broilers Fed Diets Not Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    T. T. dos Santos

    2013-02-01

    Full Text Available Phytate is not only an unavailable source of phosphorus (P for broilers but it also acts as an anti-nutrient, reducing protein and mineral absorption, increasing endogenous losses and reducing broiler performance. The objective of this study was to investigate the anti-nutritional effects of phytate by including high levels of phytase in diets not severely limited in available P. A total of 768 male Arbor Acres broilers were distributed in six treatments of eight replicate pens of 16 birds each consisting of a positive control diet (PC, positive control with 500 FTU/kg phytase, negative control (NC diet with lower available P and calcium (Ca levels and the same NC diet with 500, 1,000 or 1,500 FTU/kg phytase. Body weight gain (BWG, feed intake (FI, feed conversion ratio (FCR and mortality were determined at 21 and 35 d of age while foot ash was determined in four birds per pen at 21 d of age. FI, FCR and foot ash where not affected by the lower mineral diets at 21 d of age nor by the enzyme inclusion but broilers fed lower Ca and available P diets had lower BWG. At 35 d of age no difference was observed between broilers fed the positive or NC diets but broilers fed 500, 1,000 and 1,500 FTU/kg on top of the NC diet had better FCR than broilers fed the positive control diet. When compared to birds fed a diet adequate in P, birds fed the same diet included with 500, 1,000 and 1,500 FTU/kg of phytase in marginally deficient available P and Ca diets had an improvement of performance. These results support the concept that hydrolysing phytate and reducing the anti-nutritional effects of phytate improves bird performance on marginally deficient diets that were not covering the P requirement of birds.

  12. The pre-rRNA processing factor DEF is rate limiting for the pathogenesis of MYCN-driven neuroblastoma.

    Science.gov (United States)

    Tao, T; Sondalle, S B; Shi, H; Zhu, S; Perez-Atayde, A R; Peng, J; Baserga, S J; Look, A T

    2017-07-06

    The nucleolar factor, digestive organ expansion factor (DEF), has a key role in ribosome biogenesis, functioning in pre-ribosomal RNA (pre-rRNA) processing as a component of the small ribosomal subunit (SSU) processome. Here we show that the peripheral sympathetic nervous system (PSNS) is very underdeveloped in def-deficient zebrafish, and that def haploinsufficiency significantly decreases disease penetrance and tumor growth rate in a MYCN-driven transgenic zebrafish model of neuroblastoma that arises in the PSNS. Consistent with these findings, DEF is highly expressed in human neuroblastoma, and its depletion in human neuroblastoma cell lines induces apoptosis. Interestingly, overexpression of MYCN in zebrafish and in human neuroblastoma cells results in the appearance of intermediate pre-rRNAs species that reflect the processing of pre-rRNAs through Pathway 2, a pathway that processes pre-rRNAs in a different temporal order than the more often used Pathway 1. Our results indicate that DEF and possibly other components of the SSU processome provide a novel site of vulnerability in neuroblastoma cells that could be exploited for targeted therapy.

  13. Weakly Deleterious Mutations and Low Rates of Recombination Limit the Impact of Natural Selection on Bacterial Genomes.

    Science.gov (United States)

    Price, Morgan N; Arkin, Adam P

    2015-12-15

    Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, "background selection" against slightly deleterious alleles should reduce the effective population size (Ne) by orders of magnitude. For example, for a well-mixed population with 10(12) individuals and a typical level of homologous recombination (r/m = 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that Ne is selection should be sufficient to drive evolution if Ne × s is >1, where s is the selection coefficient. We found that this remains approximately correct if background selection is occurring or when population structure is present. Overall, we predict that even for free-living bacteria with enormous populations, natural selection is only a significant force if s is above 10(-7) or so. Because bacteria form huge populations with trillions of individuals, the simplest theoretical prediction is that the better allele at a site would predominate even if its advantage was just 10(-9) per generation. In other words, virtually every nucleotide would be at the local optimum in most individuals. A more sophisticated theory considers that bacterial genomes have millions of sites each and selection events on these many sites could interfere with each other, so that only larger effects would be important. However, bacteria can exchange genetic material, and in principle, this exchange could eliminate the interference between the evolution of the sites. We used simulations to confirm that during multisite evolution with realistic levels of recombination, only larger effects are important. We propose that advantages of less than 10(-7) are effectively neutral. Copyright © 2015 Price and Arkin.

  14. Acute adjustments of heart rate and oxygen consuption in an experimental protocol of step training with diferent combinations of platform height and musical rhythms - doi: 10.4025/actascihealthsci.v35i2.11669

    Directory of Open Access Journals (Sweden)

    Viviane Ribeiro de Ávila

    2013-06-01

    Full Text Available The aim of this study was to investigate adaptations acute heart rate (HR and oxygen consumption (VO2 in an experimental protocol of step training with different combinations of platform height (15.2, 20.3 and 25.4 cm and musical rhythms (125, 135 and 145 bpm. Thirty-five women were randomly selected, (mean ± DP aged 21.6 ± 1.8 years, body weight of 57.8 ± 8.2 kg, height of 162.6 ± 6.8 cm, body mass index of 21.8 ± 2.5 kg m-2 and fat percentage (% Fat of 24.8 ± 4.4%, with at least six months experience in step training sessions, and a frequency of at least two days a week. Techniques of descriptive and inferential statistics were employed. A significant difference was detected for the HR and VO2 in relation to the increase in step platform height and in musical rhythm for all the combinations, except for three situations. From the obtained results, we can infer that the cardiovascular and metabolic responses increase or decrease according to the musical rhythm and/or platform height.

  15. Forming limit curves of DP600 determined in high-speed Nakajima tests and predicted by two different strain-rate-sensitive models

    Science.gov (United States)

    Weiß-Borkowski, Nathalie; Lian, Junhe; Camberg, Alan; Tröster, Thomas; Münstermann, Sebastian; Bleck, Wolfgang; Gese, Helmut; Richter, Helmut

    2018-05-01

    Determination of forming limit curves (FLC) to describe the multi-axial forming behaviour is possible via either experimental measurements or theoretical calculations. In case of theoretical determination, different models are available and some of them consider the influence of strain rate in the quasi-static and dynamic strain rate regime. Consideration of the strain rate effect is necessary as many material characteristics such as yield strength and failure strain are affected by loading speed. In addition, the start of instability and necking depends not only on the strain hardening coefficient but also on the strain rate sensitivity parameter. Therefore, the strain rate dependency of materials for both plasticity and the failure behaviour is taken into account in crash simulations for strain rates up to 1000 s-1 and FLC can be used for the description of the material's instability behaviour at multi-axial loading. In this context, due to the strain rate dependency of the material behaviour, an extrapolation of the quasi-static FLC to dynamic loading condition is not reliable. Therefore, experimental high-speed Nakajima tests or theoretical models shall be used to determine the FLC at high strain rates. In this study, two theoretical models for determination of FLC at high strain rates and results of experimental high-speed Nakajima tests for a DP600 are presented. One of the theoretical models is the numerical algorithm CRACH as part of the modular material and failure model MF GenYld+CrachFEM 4.2, which is based on an initial imperfection. Furthermore, the extended modified maximum force criterion considering the strain rate effect is also used to predict the FLC. These two models are calibrated by the quasi-static and dynamic uniaxial tensile tests and bulge tests. The predictions for the quasi-static and dynamic FLC by both models are presented and compared with the experimental results.

  16. Violaxanthin de-epoxidase is rate-limiting for non-photochemical quenching under subsaturating light or during chilling in Arabidopsis.

    Science.gov (United States)

    Chen, Zhong; Gallie, Daniel R

    2012-09-01

    In response to conditions of excess light energy, plants induce non-photochemical quenching (NPQ) as a protective mechanism to prevent over reduction of photosystem II and the generation of reactive oxygen species (ROS). The xanthophyll cycle, which contributes significantly to reversible NPQ to thermally dissipate excess absorbed light energy, involves de-epoxidation of violaxanthin and antheraxanthin to zeaxanthin in response to excess light energy. The activation of violaxanthin de-epoxidase (VDE), which catalyzes the de-epoxidation reaction, requires the generation of a light-induced, transthylakoid pH gradient. In this work, we overexpressed or repressed the expression of VDE in Arabidopsis (Arabidopsis thaliana) to examine whether VDE is rate-limiting for the induction of NPQ. Increasing VDE expression increased the de-epoxidation state of xanthophyll pigments, the rate of NPQ induction, and the level of NPQ achieved under subsaturating light. In saturating light, however, overexpression of VDE did not increase the xanthophyll pigment de-epoxidation state, the level of NPQ achieved following its initial induction, or substantially improve tolerance to high light. Only under chilling, which reduces VDE activity, did an increase in VDE expression provide slightly greater phototolerance. Repression of VDE expression impaired violaxanthin de-epoxidation, reduced the generation of NPQ, and lowered the level of NPQ achieved while increasing photosensitivity. These results demonstrate that the endogenous level of VDE is rate-limiting for NPQ in Arabidopsis under subsaturating but not saturating light and can become rate-limiting under chilling conditions. These results also show that increasing VDE expression confers greater phototolerance mainly under conditions which limit endogenous VDE activity. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  17. A Generalized Adsorption Rate Model Based on the Limiting-Component Constraint in Ion-Exchange Chromatographic Separation for Multicomponent Systems

    DEFF Research Database (Denmark)

    such that conventional LDF (linear driving force) type models are extended to inactive zones without loosing their generality. Based on a limiting component constraint, an exchange probability kernel is developed for multi-component systems. The LDF-type model with the kernel is continuous with time and axial direction....... Two tuning parameters such as concentration layer thickness and function change rate at the threshold point are needed for the probability kernels, which are not sensitive to problems considered....

  18. Tenax TA extraction to understand the rate-limiting factors in methyl-β-cyclodextrin-enhanced bioremediation of PAH-contaminated soil.

    Science.gov (United States)

    Sun, Mingming; Luo, Yongming; Teng, Ying; Christie, Peter; Jia, Zhongjun; Li, Zhengao

    2013-06-01

    The effectiveness of many bioremediation systems for PAH-contaminated soil may be constrained by low contaminant bioaccessibility due to limited aqueous solubility or large sorption capacity. Information on the extent to which PAHs can be readily biodegraded is of vital importance in the decision whether or not to remediate a contaminated soil. In the present study the rate-limiting factors in methyl-β-cyclodextrin (MCD)-enhanced bioremediation of PAH-contaminated soil were evaluated. MCD amendment at 10 % (w/w) combined with inoculation with the PAH-degrading bacterium Paracoccus sp. strain HPD-2 produced maximum removal of total PAHs of up to 35 %. The desorption of PAHs from contaminated soil was determined before and after 32 weeks of bioremediation. 10 % (w/w) MCD amendment (M2) increased the Tenax extraction of total PAHs from 12 to 30 % and promoted degradation by up to 26 % compared to 6 % in the control. However, the percentage of Tenax extraction for total PAHs was much larger than that of degradation. Thus, in the control and M2 treatment it is likely that during the initial phase the bioaccessibility of PAHs is high and biodegradation rates may be limited by microbial processes. On the other hand, when the soil was inoculated with the PAH-degrading bacterium (CKB and MB2), the slowly and very slowly desorbing fractions (F sl and F vl ) became larger and the rate constants of slow and very slow desorption (k sl and k vl ) became extremely small after bioremediation, suggesting that desorption is likely rate limiting during the second, slow phase of biotransformation. These results have practical implications for site risk assessment and cleanup strategies.

  19. New age- and sex-specific criteria for QT prolongation based on rate correction formulas that minimize bias at the upper normal limits.

    Science.gov (United States)

    Rautaharju, Pentti M; Mason, Jay W; Akiyama, Toshio

    2014-07-01

    Existing formulas for rate-corrected QT (QTc) commonly fail to properly adjust the upper normal limits which are more critical than the mean QTc for evaluation of prolonged QT. Age- and sex-related differences in QTc are also often overlooked. Our goal was to establish criteria for prolonged QTc using formulas that minimize QTc bias at the upper normal limits. Strict criteria were used in selecting a study group of 57,595 persons aged 5 to 89 years (54% women) and to exclude electrocardiograms (ECG) with possible disease-associated changes. Two QT rate adjustment formulas were identified which both minimized rate-dependency in the 98 th percentile limits: QTcmod, based on an electrophysiological model (QTcMod = QTx(120 + HR)/180)), and QTcLogLin, a power function of the RR interval with exponents 0.37 for men and 0.38 for women. QTc shortened in men during adolescence and QTcMod became 13 ms shorter than in women at age 20-29 years. The sex difference was maintained through adulthood although decreasing with age. The criteria established for prolonged QTc were: Age < 40 years, men 430 ms, women 440 ms; Age 40 to 69, men 440 ms, women 450 ms; Age ≥ 70 years, men 455 ms, and women 460 ms. Sex difference in QTc originates from shortened QT in adolescent males. Upper normal limits for QTc vary substantially by age and sex, and it is essential to use age- and sex-specific criteria for evaluation of QT prolongation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Removal of nutrient limitations in forest gaps enhances growth rate and resistance to cavitation in subtropical canopy tree species differing in shade tolerance.

    Science.gov (United States)

    Villagra, Mariana; Campanello, Paula I; Montti, Lia; Goldstein, Guillermo

    2013-03-01

    A 4-year fertilization experiment with nitrogen (N) and phosphorus (P) was carried out in natural gaps of a subtropical forest in northeastern Argentina. Saplings of six dominant canopy species differing in shade tolerance were grown in five control and five N + P fertilized gaps. Hydraulic architectural traits such as wood density, the leaf area to sapwood area ratio (LA : SA), vulnerability to cavitation (P50) and specific and leaf-specific hydraulic conductivity were measured, as well as the relative growth rate, specific leaf area (SLA) and percentage of leaf damage by insect herbivores. Plant growth rates and resistance to drought-induced embolisms increased when nutrient limitations were removed. On average, the P50 of control plants was -1.1 MPa, while the P50 of fertilized plants was -1.6 MPa. Wood density and LA : SA decreased with N + P additions. A trade-off between vulnerability to cavitation and efficiency of water transport was not observed. The relative growth rate was positively related to the total leaf surface area per plant and negatively related to LA : SA, while P50 was positively related to SLA across species and treatments. Plants with higher growth rates and higher total leaf area in fertilized plots were able to avoid hydraulic dysfunction by becoming less vulnerable to cavitation (more negative P50). Two high-light-requiring species exhibited relatively low growth rates due to heavy herbivore damage. Contrary to expectations, shade-tolerant plants with relatively high resistance to hydraulic dysfunction and reduced herbivory damage were able to grow faster. These results suggest that during the initial phase of sapling establishment in gaps, species that were less vulnerable to cavitation and exhibited reduced herbivory damage had faster realized growth rates than less shade-tolerant species with higher potential growth rates. Finally, functional relationships between hydraulic traits and growth rate across species and treatments

  1. Focal cryotherapy: step by step technique description

    Directory of Open Access Journals (Sweden)

    Cristina Redondo

    Full Text Available ABSTRACT Introduction and objective: Focal cryotherapy emerged as an efficient option to treat favorable and localized prostate cancer (PCa. The purpose of this video is to describe the procedure step by step. Materials and methods: We present the case of a 68 year-old man with localized PCa in the anterior aspect of the prostate. Results: The procedure is performed under general anesthesia, with the patient in lithotomy position. Briefly, the equipment utilized includes the cryotherapy console coupled with an ultrasound system, argon and helium gas bottles, cryoprobes, temperature probes and an urethral warming catheter. The procedure starts with a real-time trans-rectal prostate ultrasound, which is used to outline the prostate, the urethra and the rectal wall. The cryoprobes are pretested and placed in to the prostate through the perineum, following a grid template, along with the temperature sensors under ultrasound guidance. A cystoscopy confirms the right positioning of the needles and the urethral warming catheter is installed. Thereafter, the freeze sequence with argon gas is started, achieving extremely low temperatures (-40°C to induce tumor cell lysis. Sequentially, the thawing cycle is performed using helium gas. This process is repeated one time. Results among several series showed a biochemical disease-free survival between 71-93% at 9-70 month- follow-up, incontinence rates between 0-3.6% and erectile dysfunction between 0-42% (1–5. Conclusions: Focal cryotherapy is a feasible procedure to treat anterior PCa that may offer minimal morbidity, allowing good cancer control and better functional outcomes when compared to whole-gland treatment.

  2. SURGICAL REMOVAL OF EPIRETINAL MEMBRANE WITH AND WITHOUT REMOVAL OF INTERNAL LIMITING MEMBRANE: Comparative Study of Visual Acuity, Features of Optical Coherence Tomography, and Recurrence Rate.

    Science.gov (United States)

    De Novelli, Fernando J; Goldbaum, Mauro; Monteiro, Mario L R; Bom Aggio, Fabio; Takahashi, Walter Y

    2017-12-05

    To study and compare visual acuity, foveal thickness, outer limiting layer, ellipsoid zone, and recurrence rate in patients undergoing removal of the epiretinal membrane with and without the removal of the internal limiting membrane (ILM). Sixty-three patients who had the epiretinal membrane removed by a single surgeon were randomly assigned into 2 groups: Group 1 without additional removal of the ILM and Group 2 with removal of the ILM. Patients were followed up and evaluated at the first month, third month, and sixth month, postoperatively. Patients from both groups had a gradual improvement in their vision over time. There was no significant difference in the improvement in visual acuity between the two groups. About tomographic assessment of alterations, no significant differences were found between the groups; however, Group 1 had a higher relapse rate (17%) compared with Group 2 (3.6%) (P = 0.09). Epiretinal membrane removal with and without ILM peeling shows similar functional and anatomical improvements, but the group in which the ILM was not removed seemed to have a higher recurrence rate.

  3. Jumps of the local magnetic field near CICC during external magnetic field ramp and their connection with the ramp rate limitation

    International Nuclear Information System (INIS)

    Vysotsky, V.S.; Takayasu, M.; Minervini, J.V.

    1997-01-01

    A new method has been developed to study Ramp Rate Limitation (RRL) phenomena. Samples of ITER-type cable-in-conduit (CICC) subcable were instrumented with local field sensors such as Hall probes and pick-up coils and then subjected to rapidly changing external magnetic field. The authors found that during fast field sweeps some discontinuous changes, or jumps occur in the local field. They believe that these jumps indicate a fast current redistribution processes inside CICC. Detailed information about local magnetic field jumps during changing field is presented. Possible origin of the jumps and their connection with RRL are discussed

  4. Service evaluation of an educational intervention to improve sexual health services in primary care implemented using a step-wedge design: analysis of chlamydia testing and diagnosis rate changes.

    Science.gov (United States)

    Town, Katy; McNulty, Cliodna A M; Ricketts, Ellie J; Hartney, Thomas; Nardone, Anthony; Folkard, Kate A; Charlett, Andre; Dunbar, J Kevin

    2016-08-02

    Providing sexual health services in primary care is an essential step towards universal provision. However they are not offered consistently. We conducted a national pilot of an educational intervention to improve staff's skills and confidence to increase chlamydia testing rates and provide condoms with contraceptive information plus HIV testing according to national guidelines, known as 3Cs&HIV. The effectiveness of the pilot on chlamydia testing and diagnosis rates in general practice was evaluated. The pilot was implemented using a step-wedge design over three phases during 2013 and 2014 in England. The intervention combined educational workshops with posters, testing performance feedback and continuous support. Chlamydia testing and diagnosis rates in participating general practices during the control and intervention periods were compared adjusting for seasonal trends in chlamydia testing and differences in practice size. Intervention effect modification was assessed for the following general practice characteristics: chlamydia testing rate compared to national median, number of general practice staff employed, payment for chlamydia screening, practice urban/rurality classification, and proximity to sexual health clinics. The 460 participating practices conducted 26,021 tests in the control period and 18,797 tests during the intervention period. Intention-to-treat analysis showed no change in the unadjusted median tests and diagnoses per month per practice after receiving training: 2.7 vs 2.7; 0.1 vs 0.1. Multivariable negative binomial regression analysis found no significant change in overall testing or diagnoses post-intervention (incidence rate ratio (IRR) 1.01, 95 % confidence interval (CI) 0.96-1.07, P = 0.72; 0.98 CI 0.84-1.15, P = 0.84, respectively). Stratified analysis showed testing increased significantly in practices where payments were in place prior to the intervention (IRR 2.12 CI 1.41-3.18, P service improvement intervention to

  5. Absence of zero-temperature transmission rate of a double-chain tight-binding model for DNA with random sequence of nucleotides in thermodynamic limit

    International Nuclear Information System (INIS)

    Xiong Gang; Wang, X.R.

    2005-01-01

    The zero-temperature transmission rate spectrum of a double-chain tight-binding model for real DNA is calculated. It is shown that a band of extended-like states exists only for finite chain length with strong inter-chain coupling. While the whole spectrum tends to zero in thermodynamic limit, regardless of the strength of inter-chain coupling. It is also shown that a more faithful model for real DNA with periodic sugar-phosphate chains in backbone structures can be mapped into the above simple double-chain tight-binding model. Combined with above results, the transmission rate of real DNA with long random sequence of nucleotides is expected to be poor

  6. Single-Step Access to Long-Chain α,ω-Dicarboxylic Acids by Isomerizing Hydroxycarbonylation of Unsaturated Fatty Acids

    KAUST Repository

    Goldbach, Verena; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Mecking, Stefan

    2016-01-01

    active Pd hydride species. Theoretical calculations identified the hydrolysis as the rate-determining step. A low nucleophile concentration in the reaction mixture in combination with this high energetic barrier limits the potential of this reaction

  7. Retrospective observation on contribution and limitations of screening for breast cancer with mammography in Korea: detection rate of breast cancer and incidence rate of interval cancer of the breast.

    Science.gov (United States)

    Lee, Kunsei; Kim, Hyeongsu; Lee, Jung Hyun; Jeong, Hyoseon; Shin, Soon Ae; Han, Taehwa; Seo, Young Lan; Yoo, Youngbum; Nam, Sang Eun; Park, Jong Heon; Park, Yoo Mi

    2016-11-18

    The purpose of this study was to determine the benefits and limitations of screening for breast cancer using mammography. Descriptive design with follow-up was used in the study. Data from breast cancer screening and health insurance claim data were used. The study population consisted of all participants in breast cancer screening from 2009 to 2014. Crude detection rate, positive predictive value and sensitivity and specificity of breast cancer screening and, incidence rate of interval cancer of the breast were calculated. The crude detection rate of breast cancer screening per 100,000 participants increased from 126.3 in 2009 to 182.1 in 2014. The positive predictive value of breast cancer screening per 100,000 positives increased from 741.2 in 2009 to 1,367.9 in 2014. The incidence rate of interval cancer of the breast per 100,000 negatives increased from 51.7 in 2009 to 76.3 in 2014. The sensitivities of screening for breast cancer were 74.6% in 2009 and 75.1% in 2014 and the specificities were 83.1% in 2009 and 85.7% in 2014. To increase the detection rate of breast cancer by breast cancer screening using mammography, the participation rate should be higher and an environment where accurate mammography and reading can be performed and reinforcement of quality control are required. To reduce the incidence rate of interval cancer of the breast, it will be necessary to educate women after their 20s to perform self-examination of the breast once a month regardless of participation in screening for breast cancer.

  8. Pressure Drop Versus Flow Rate Analysis of the Limited Streamer Tube Gas System of the BaBar Muon Detector Upgrade

    International Nuclear Information System (INIS)

    Yi, M.

    2004-01-01

    It has been proposed that Limited Streamer Tubes (LST) be used in the current upgrade of the muon detector in the BaBar detector. An LST consists of a thin silver plated wire centered in a graphite-coated cell. One standard LST tube consists of eight such cells, and two or three such tubes form an LST module. Under operation, the cells are filled with a gas mixture of CO 2 , argon and isobutane. During normal operation of the detector, the gas will be flushed out of the system at a constant low rate of one volume change per day. During times such as installation, however, it is often desired to flush and change the LST gas volumes very rapidly, leading to higher than normal pressure which may damage the modules. This project studied this pressure as a function of flow rate and the number of modules that are put in series in search of the maximal safe flow rate at which to flush the modules. Measurements of pressure drop versus flow rate were taken using a flow meter and a pressure transducer on configurations of one to five modules put in series. Minimal Poly-Flo tubing was used for all connections between test equipment and modules. They contributed less than 25% to all measurements. A ratio of 0.00022 ± 0.00001 mmHg per Standard Cubic Centimeter per Minute (SCCM) per module was found, which was a slight overestimate since it included the contributions from the tubing connections. However, for the purpose of finding a flow rate at which the modules can be safely flushed, this overestimate acts as a safety cushion. For a standard module with a volume of 16 liters and a known safe overpressure of 2 inches of water, the ratio translates into a flow rate of 17000 ± 1000SCCM and a time requirement of 56 ± 5 seconds to flush an entire module

  9. Continuous injection rate-shaping for passenger-car diesel engines. Potential, limits and feasibility; Kontinuierliche Einspritzverlaufsformung in Pkw-Dieselmotoren. Potenziale, Grenzen und Realisierungschancen

    Energy Technology Data Exchange (ETDEWEB)

    Predelli, Oliver; Gratzke, Ralf; Sommer, Ansgar; Marohn, Ralf [Ingenieurgesellschaft Auto und Verkehr GmbH, Berlin (Germany); Atzler, Frank; Schuele, Harry; Kastner, Oliver; Nozeran, Nicolas [Continental Automotive GmbH, Regensburg (Germany)

    2010-07-01

    Injection-rate shaping for passenger-car diesel engines is a technique on the verge of a breakthrough. In addition to reducing particulate emission, the method is capable of significantly cutting combustion noise, the Achilles heel of the DI diesel combustion process. As a result, injection-rate shaping shows clear advantages over alternative lowemission combustion processes, such as PCCI, which, although also capable of improving raw emissions in relation to NO{sub x} and soot, are less convincing from the aspect of diesel knock and the emission of CO and CO{sub 2}. Of the modern Common-Rail injection systems, only two permit continuous injection-rate shaping in addition to the hitherto customary strategy of multiple injection. One of them is the Continental PCR NG system. This uses piezo-actuated Common-Rail injectors with direct actuation of the injector nozzle needle. The electronic engine control system provides the capability of determining how far the injector nozzle needle opens. The ability to control the injection curve of each individual injection event gives the engine developer new degrees of freedom in optimizing the combustion process. This paper investigates the way in which the operating behavior of a passenger-car diesel engine is affected by an injection-rate that can be shaped flexibly across broad ranges. Injection-rate shaping aims to use high injection pressures at part load without affecting acoustics and with a view to achieving a significant improvement in emission behavior. The investigation also points out this technique's limits in individual operating points. It furthermore demonstrates approaches suitable for use in mass production with regard to controlling injection-rate shaping in real time in the engine control unit as a way of providing combustion-process stability over the life of the engine. (orig.)

  10. Upper limits to the reaction rate coefficients of C(n)(-) and C(n)H(-) (n = 2, 4, 6) with molecular hydrogen.

    Science.gov (United States)

    Endres, Eric S; Lakhmanskaya, Olga; Hauser, Daniel; Huber, Stefan E; Best, Thorsten; Kumar, Sunil S; Probst, Michael; Wester, Roland

    2014-08-21

    In the interstellar medium (ISM) ion–molecule reactions play a key role in forming complex molecules. Since 2006, after the radioastronomical discovery of the first of by now six interstellar anions, interest has grown in understanding the formation and destruction pathways of negative ions in the ISM. Experiments have focused on reactions and photodetachment of the identified negatively charged ions. Hints were found that the reactions of CnH(–) with H2 may proceed with a low (rate [Eichelberger, B.; et al. Astrophys. J. 2007, 667, 1283]. Because of the high abundance of molecular hydrogen in the ISM, a precise knowledge of the reaction rate is needed for a better understanding of the low-temperature chemistry in the ISM. A suitable tool to analyze rare reactions is the 22-pole radiofrequency ion trap. Here, we report on reaction rates for Cn(–) and CnH(–) (n = 2, 4, 6) with buffer gas temperatures of H2 at 12 and 300 K. Our experiments show the absence of these reactions with an upper limit to the rate coefficients between 4 × 10(–16) and 5 × 10(–15) cm(3) s(–1), except for the case of C2(–), which does react with a finite rate with H2 at low temperatures. For the cases of C2H(–) and C4H(–), the experimental results were confirmed with quantum chemical calculations. In addition, the possible influence of a residual reactivity on the abundance of C4H(–) and C6H(–) in the ISM were estimated on the basis of a gas-phase chemical model based on the KIDA database. We found that the simulated ion abundances are already unaffected if reaction rate coefficients with H2 were below 10(–14) cm(3) s(–1).

  11. Duration of slip-resistant shoe usage and the rate of slipping in limited-service restaurants: results from a prospective and crossover study.

    Science.gov (United States)

    Verma, Santosh K; Zhao, Zhe; Courtney, Theodore K; Chang, Wen-Ruey; Lombardi, David A; Huang, Yueng-Hsiang; Brennan, Melanye J; Perry, Melissa J

    2014-01-01

    Several studies have indicated that slip-resistant shoes may have a positive effect on reducing the risk of slips and falls, a leading cause of injury at work. Few studies, however, have examined how duration of shoe usage affects their slip-resistance properties. This study examined the association between the duration of slip-resistant shoes usage and the self-reported rate of slipping in limited-service restaurant workers. A total of 475 workers from 36 limited-service restaurants in the USA were recruited to participate in a 12-week prospective study of workplace slipping. Of the 475 participants, 83 reported changing to a new pair of shoes at least once during the 12-week follow-up. The results show that slip-resistant shoes worn for less than six months were moderately more effective than those worn for more than six months. Changing to a new pair of shoes among those wearing slip-resistant shoes at baseline was associated with a 55% reduction in the rate of slipping (RR = 0.45, 95% CI = 0.23-0.89). Further research is needed to develop criteria for the replacement of slip-resistant shoes.

  12. Control Software for Piezo Stepping Actuators

    Science.gov (United States)

    Shields, Joel F.

    2013-01-01

    A control system has been developed for the Space Interferometer Mission (SIM) piezo stepping actuator. Piezo stepping actuators are novel because they offer extreme dynamic range (centimeter stroke with nanometer resolution) with power, thermal, mass, and volume advantages over existing motorized actuation technology. These advantages come with the added benefit of greatly reduced complexity in the support electronics. The piezo stepping actuator consists of three fully redundant sets of piezoelectric transducers (PZTs), two sets of brake PZTs, and one set of extension PZTs. These PZTs are used to grasp and move a runner attached to the optic to be moved. By proper cycling of the two brake and extension PZTs, both forward and backward moves of the runner can be achieved. Each brake can be configured for either a power-on or power-off state. For SIM, the brakes and gate of the mechanism are configured in such a manner that, at the end of the step, the actuator is in a parked or power-off state. The control software uses asynchronous sampling of an optical encoder to monitor the position of the runner. These samples are timed to coincide with the end of the previous move, which may consist of a variable number of steps. This sampling technique linearizes the device by avoiding input saturation of the actuator and makes latencies of the plant vanish. The software also estimates, in real time, the scale factor of the device and a disturbance caused by cycling of the brakes. These estimates are used to actively cancel the brake disturbance. The control system also includes feedback and feedforward elements that regulate the position of the runner to a given reference position. Convergence time for smalland medium-sized reference positions (less than 200 microns) to within 10 nanometers can be achieved in under 10 seconds. Convergence times for large moves (greater than 1 millimeter) are limited by the step rate.

  13. The effects of acclimation and rates of temperature change on critical thermal limits in Tenebrio molitor (Tenebrionidae) and Cyrtobagous salviniae (Curculionidae).

    Science.gov (United States)

    Allen, Jessica L; Clusella-Trullas, Susana; Chown, Steven L

    2012-05-01

    Critical thermal limits provide an indication of the range of temperatures across which organisms may survive, and the extent of the lability of these limits offers insights into the likely impacts of changing thermal environments on such survival. However, investigations of these limits may be affected by the circumstances under which trials are undertaken. Only a few studies have examined these effects, and typically not for beetles. This group has also not been considered in the context of the time courses of acclimation and its reversal, both of which are important for estimating the responses of species to transient temperature changes. Here we therefore examine the effects of rate of temperature change on critical thermal maxima (CT(max)) and minima (CT(min)), as well as the time course of the acclimation response and its reversal in two beetle species, Tenebrio molitor and Cyrtobagous salviniae. Increasing rates of temperature change had opposite effects on T. molitor and C. salviniae. In T. molitor, faster rates of change reduced both CT(max) (c. 2°C) and CT(min) (c. 3°C), while in C. salviniae faster rates of change increased both CT(max) (c. 6°C) and CT(min) (c. 4°C). CT(max) in T. molitor showed little response to acclimation, while the response to acclimation of CT(min) was most pronounced following exposure to 35°C (from 25°C) and was complete within 24 h. The time course of acclimation of CT(max) in C. salviniae was 2 days when exposed to 36°C (from c. 26°C), while that of CT(min) was less than 3 days when exposed to 18°C. In T. molitor, the time course of reacclimation to 25°C after treatments at 15°C and 35°C at 75% RH was longer than the time course of acclimation, and varied from 3-6 days for CT(max) and 6 days for CT(min). In C. salviniae, little change in CT(max) and CT(min) (molitor and C. salviniae may be restricted in their ability to respond to transient temperature changes at short-time scales, and instead may have to rely on

  14. Isotopic dilution methods to determine the gross transformation rates of nitrogen, phosphorus, and sulfur in soil: a review of the theory, methodologies, and limitations

    International Nuclear Information System (INIS)

    Di, H. J.; Cameron, K. C.; McLaren, R. G.

    2000-01-01

    The rates at which nutrients are released to, and removed from, the mineral nutrient pool are important in regulating the nutrient supply to plants. These nutrient transformation rates need to be taken into account when developing nutrient management strategies for economical and sustainable production. A method that is gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The technique involves labelling a soil mineral nutrient pool, e.g. NH 4 + , NO 3 - , PO 4 3- , or SO 4 2- , and monitoring the changes with time of the size of the labelled nutrient pool and the excess tracer abundance (atom %, if stable isotope tracer is used) or specific activity (if radioisotope is used) in the nutrient pool. Because of the complexity of the concepts and procedures involved, the method has sometimes been used incorrectly, and results misinterpreted. This paper discusses the isotopic dilution technique, including the theoretical background, the methodologies to determine the gross flux rates of nitrogen, phosphorus, and sulfur, and the limitations of the technique. The assumptions, conceptual models, experimental procedures, and compounding factors are discussed. Possible effects on the results by factors such as the uniformity of tracer distribution in the soil, changes in soil moisture content, substrate concentration, and aeration status, and duration of the experiment are also discussed. The influx and out-flux transformation rates derived from this technique are often contributed by several processes simultaneously, and thus cannot always be attributed to a particular nutrient transformation process. Despite the various constraints or possible compounding factors, the technique is a valuable tool that can provide important quantitative information on nutrient dynamics in the soil-plant system. Copyright (2000) CSIRO Publishing

  15. Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition.

    Science.gov (United States)

    Gomes, Aurélie; Guillaume, Ludivine; Grimes, David Robert; Fehrenbach, Jérôme; Lobjois, Valérie; Ducommun, Bernard

    2016-01-01

    The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems.

  16. Report and recommendations in the matter of British Columbia Hydro and Power Authority and an inquiry into a Heritage Contract for British Columbia Hydro and Power Authority's existing generation resources and regarding stepped rates and transmission access

    International Nuclear Information System (INIS)

    Hobbs, R.H.; Hall, K.L.; Bradley, P.G.

    2003-01-01

    Under British Columbia's new energy plan, the BC Utilities Commission made recommendations on two main policy initiatives regarding regulation of BC Hydro. The first involved a Heritage Contract that would ensure any benefits attributable to the existing low-cost generation of BC Hydro would be secured for British Columbians. The Heritage Contract had the support of all participants. The proposal was based on the revenue required by Generation to meet the cost of supplying the energy of Heritage Resources to Distribution. The second recommendation involved a stepped rate structure for large commercial and industrial customers to encourage a more efficient use of energy resources and private investments in new generation. It also recommends concurrent implementation of time-of-use rates. BC Hydro had also proposed a significant change in the determination and disposition of Trade Income between BC Hydro and Powerex. The agreement stipulated that Trade Income would no longer include revenues from the sale of surplus power, except for profits realized by Powerex after paying BC Hydro an indexed price for surplus power. All Trade income up to $200 million would accrue to the ratepayers. This report presents 3 alternatives to the Trade Income proposal and several others recommendations dealing with transmission voltage customers and generation access, legislation, regulation and special directions. The report identified a schedule for implementation of retail access by the end of 2004. 9 appendices

  17. Internship guide : Work placements step by step

    NARCIS (Netherlands)

    Haag, Esther

    2013-01-01

    Internship Guide: Work Placements Step by Step has been written from the practical perspective of a placement coordinator. This book addresses the following questions : what problems do students encounter when they start thinking about the jobs their degree programme prepares them for? How do you

  18. The way to collisions, step by step

    CERN Multimedia

    2009-01-01

    While the LHC sectors cool down and reach the cryogenic operating temperature, spirits are warming up as we all eagerly await the first collisions. No reason to hurry, though. Making particles collide involves the complex manoeuvring of thousands of delicate components. The experts will make it happen using a step-by-step approach.

  19. The Relaxation of Vicinal (001) with ZigZag [110] Steps

    Science.gov (United States)

    Hawkins, Micah; Hamouda, Ajmi Bh; González-Cabrera, Diego Luis; Einstein, Theodore L.

    2012-02-01

    This talk presents a kinetic Monte Carlo study of the relaxation dynamics of [110] steps on a vicinal (001) simple cubic surface. This system is interesting because [110] steps have different elementary excitation energetics and favor step diffusion more than close-packed [100] steps. In this talk we show how this leads to relaxation dynamics showing greater fluctuations on a shorter time scale for [110] steps as well as 2-bond breaking processes being rate determining in contrast to 3-bond breaking processes for [100] steps. The existence of a steady state is shown via the convergence of terrace width distributions at times much longer than the relaxation time. In this time regime excellent fits to the modified generalized Wigner distribution (as well as to the Berry-Robnik model when steps can overlap) were obtained. Also, step-position correlation function data show diffusion-limited increase for small distances along the step as well as greater average step displacement for zigzag steps compared to straight steps for somewhat longer distances along the step. Work supported by NSF-MRSEC Grant DMR 05-20471 as well as a DOE-CMCSN Grant.

  20. Study on indoor radon concentration and gamma radiation dose rate in different rooms in some dwellings around Bharath Gold Mines Limited, Karnataka State, India

    International Nuclear Information System (INIS)

    Umesha Reddy, K.; Jayasheelan, A.; Sannappa, J.

    2012-01-01

    Indoor radon contributes significantly to the total radiation exposure caused to human beings. The indoor concentration of radon in different rooms in the same type of dwellings around Bharath Gold Mines Limited (BGML), Karnataka State (12°57' min N and 78°16' min E) were measured by using LR-115 (type-Il) Solid State Nuclear Track Detectors (SSNTDs). The maximum indoor radon concentration is observed in the bathroom and minimum in the hall. The maximum average indoor radon concentration is observed in the Champion and minimum in the BEML nagar. The indoor gamma radiation dose rate is also measured in these locations using scintillometer. The geology of this part forms predominantly Hornblende Schist, Granite gneiss, Champion gneiss, Quartzite etc. The indoor radon concentration shows good correlation with the indoor gamma radiation dose. (author)

  1. A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes

    Science.gov (United States)

    Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

    2012-01-01

    Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c) 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

  2. Linking chloride mass balance infiltration rates with chlorofluorocarbon and SF6 groundwater dating in semi-arid settings: potential and limitations.

    Science.gov (United States)

    Stadler, Susanne; Osenbruck, Karsten; Duijnisveld, Wilhelmus H M; Schwiede, Martin; Bottcher, Jurgen

    2010-09-01

    In the framework of the investigation of enrichment processes of nitrate in groundwater of the Kalahari of Botswana near Serowe, recharge processes were investigated. The thick unsaturated zone extending to up to 100 m of mostly unconsolidated sediments and very low recharge rates pose a serious challenge to study solute transport related to infiltration and recharge processes, as this extends past the conventional depths of soil scientific investigations and is difficult to describe using evidence from the groundwater due to the limitations imposed by available tracers. To determine the link between nitrate in the vadose zone and in the uppermost groundwater, sediment from the vadose zone was sampled up to a depth of 15-20 m (in one case also to 65 m) on several sites with natural vegetation in the research area. Among other parameters, sediment and water were analysed to determine chloride and nitrate concentration depth profiles. Using the chloride mass balance method, an estimation of groundwater infiltration rates produced values of 0.2-4 mm a(-1). The uncertainty of these values is, however, high. Because of the extreme thickness of the vadose zone, the travel time in the unsaturated zone might reach extreme values of up to 500 years and more. For investigations using groundwater, we applied the chlorofluorocarbons CFC-113, CFC-12, sulphur hexafluoride (SF(6)) and tritium to identify potential recharge, and found indications for some advective transport of the CFCs and SF(6), which we accounted for as constituting potential active localised recharge. In our contribution, we show the potential and limitations of the applied methods to determine groundwater recharge and coupled solute transport in semi-arid settings, and compare travel time ranges derived from soil science and groundwater investigations.

  3. High similarity of phylogenetic profiles of rate-limiting enzymes with inhibitory relation in Human, Mouse, Rat, budding Yeast and E. coli.

    Science.gov (United States)

    Zhao, Min; Qu, Hong

    2011-11-30

    The phylogenetic profile is widely used to characterize functional linkage and conservation between proteins without amino acid sequence similarity. To survey the conservative regulatory properties of rate-limiting enzymes (RLEs) in metabolic inhibitory network across different species, we define the enzyme inhibiting pair as: where the first enzyme in a pair is the inhibitor provider and the second is the target of the inhibitor. Phylogenetic profiles of enzymes in the inhibiting pairs are further generated to measure the functional linkage of these enzymes during evolutionary history. We find that the RLEs generate, on average, over half of all in vivo inhibitors in each surveyed model organism. And these inhibitors inhibit on average over 85% targets in metabolic inhibitory network and cover the majority of targets of cross-pathway inhibiting relations. Furthermore, we demonstrate that the phylogenetic profiles of the enzymes in inhibiting pairs in which at least one enzyme is rate-limiting often show higher similarities than those in common inhibiting enzyme pairs. In addition, RLEs, compared to common metabolic enzymes, often tend to produce ADP instead of AMP in conservative inhibitory networks. Combined with the conservative roles of RLEs in their efficiency in sensing metabolic signals and transmitting regulatory signals to the rest of the metabolic system, the RLEs may be important molecules in balancing energy homeostasis via maintaining the ratio of ATP to ADP in living cells. Furthermore, our results indicate that similarities of phylogenetic profiles of enzymes in the inhibiting enzyme pairs are not only correlated with enzyme topological importance, but also related with roles of the enzymes in metabolic inhibitory network.

  4. Comparison of false-negative rates and limits of detection following macrofoam-swab sampling of Bacillus anthracis surrogates via Rapid Viability PCR and plate culture.

    Science.gov (United States)

    Hutchison, J R; Piepel, G F; Amidan, B G; Hess, B M; Sydor, M A; Deatherage Kaiser, B L

    2018-05-01

    We evaluated the effects of Bacillus anthracis surrogates, low surface concentrations, surface materials and assay methods on false-negative rate (FNR) and limit of detection (LOD 95 ) for recovering Bacillus spores using a macrofoam-swab sampling procedure. Bacillus anthracis Sterne or Bacillus atrophaeus Nakamura spores were deposited over a range of low target concentrations (2-500 per coupon) onto glass, stainless steel, vinyl tile and plastic. Samples were assayed using a modified Rapid Viability-PCR (mRV-PCR) method and the traditional plate culture method to obtain FNR and LOD 95 results. Mean FNRs tended to be lower for mRV-PCR compared to culturing, and increased as spore concentration decreased for all surface materials. Surface material, but not B. anthracis surrogate, influenced FNRs with the mRV-PCR method. The mRV-PCR LOD 95 was lowest for glass and highest for vinyl tile. LOD 95 values overall were lower for mRV-PCR than for the culture method. This study adds to the limited data on FNR and LOD 95 for mRV-PCR and culturing methods with low concentrations of B. anthracis sampled from various surface materials by the CDC macrofoam-swab method. These are key inputs for planning characterization and clearance studies for low contamination levels of B. anthracis. © 2018 The Society for Applied Microbiology.

  5. Happiness and life satisfaction prospectively predict self-rated health, physical health, and the presence of limiting, long-term health conditions.

    Science.gov (United States)

    Siahpush, Mohammad; Spittal, Matt; Singh, Gopal K

    2008-01-01

    To examine the effect of happiness and life satisfaction on health. Longitudinal data from waves 1 and 3, conducted in 2001 and 2004, respectively, of the Household Income and Labour Dynamics in Australia survey. Australia. A total of 9981 respondents aged 18 years and older. Outcomes were self-reported health; the absence of long-term, limiting health conditions; and physical health. Happiness was assessed with the following question: "During the past 4 weeks, have you been a happy person"? Life satisfaction was determined with the following question: "All things considered, how satisfied are you with your life"? We used multiple regression analysis to estimate odds ratios (ORs), beta coefficients (beta), and 95% confidence intervals (CIs) for the associations between baseline happiness or life satisfaction and health at wave 3. Baseline happiness and life satisfaction both were positively associated at wave 3 with excellent, very good, or good health (OR = 1.50, CI = 1.33-1.70, p < .0001; and OR = 1.62, CI = 1.27-2.08, p < .0001, respectively); with the absence of long-term, limiting health conditions (OR = 1.53, CI = 1.35-1.75, p < .0001; and OR = 1.51, CI = 1.25-1.82, p < .0001, respectively); and with higher physical health levels (beta = .99, CI = .60-1.39, p < .0001; and beta = .99, CI = .20-1.78, p < .0145, respectively). This study showed that happier people and those who were more satisfied with their lives at baseline reported better health (self-rated health; absence of limiting, long-term conditions; and physical health) at the 2-year follow-up when adjusted for baseline health and other relevant covariates.

  6. Microsoft Office professional 2010 step by step

    CERN Document Server

    Cox, Joyce; Frye, Curtis

    2011-01-01

    Teach yourself exactly what you need to know about using Office Professional 2010-one step at a time! With STEP BY STEP, you build and practice new skills hands-on, at your own pace. Covering Microsoft Word, PowerPoint, Outlook, Excel, Access, Publisher, and OneNote, this book will help you learn the core features and capabilities needed to: Create attractive documents, publications, and spreadsheetsManage your e-mail, calendar, meetings, and communicationsPut your business data to workDevelop and deliver great presentationsOrganize your ideas and notes in one placeConnect, share, and accom

  7. Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

    KAUST Repository

    Soury, Hamza

    2017-03-14

    This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have non-line of sight (NLOS) interfering link. Consequently, we study the interferer limited problem that appears between NLOS HD users-pair that are scheduled on the same FD channel. The distribution of the interference is first characterized via its distribution function, which is derived in closed form. Then, a comprehensive performance assessment for the proposed pairing scheme is provided by assuming Extended Generalized- $cal{K}$ (EGK) fading for the downlink and studying different modulation schemes. To this end, a unified closed form expression for the average symbol error rate is derived. Furthermore, we show the effective downlink throughput gain harvested by the pairing NLOS users as a function of the average signal-to-interferenceratio when compared to an idealized HD scenario with neither interference nor noise. Finally, we show the minimum required channel gain pairing threshold to harvest downlink throughput via the FD operation when compared to the HD case for each modulation scheme.

  8. Limited Seed and Seed Yield Response of Calendula to Applied Nitrogen Does Not Justify Risk of Environmental Damage from High Urea Application Rates

    Directory of Open Access Journals (Sweden)

    Jane M. F. Johnson

    2018-03-01

    Full Text Available Calendula (Calendula officinalis L. seed, due to its high calendic acid content, is recognized as a potential environmentally safe substitute for volatile organic compounds. Agronomic guidelines for nitrogen (N management to produce calendula seed oil on a commercial scale are limited. Post-harvest soil N has the potential to move off-farm and contribute to water quality degradation (e.g., hypoxia in the Gulf of Mexico. Establishing N management guidelines should consider agronomic response and potential environmental risk. Calendula seed and oil yield, oil content, harvest index, N use, seed N use efficiency, oil N use efficiency, agronomic efficiency, vegetative growth, and the amount of residual soil-N following harvest response to five urea N rates (0, 34, 67, 134, and 202 kg N ha−1 were assessed in a replicated field study repeated for two growing seasons. Seed yield increased with N rate, but because of the low N conversion efficiency, there appeared to be minimal yield gains in applying N beyond 34 kg ha−1. The lowest amount of soil-N left underutilized in the soil was predicted to occur at 39 kg N ha−1 and was adequate for seed and seed oil commercial calendula production on a Mollisol in the Northern Midwest United States.

  9. One Step Quantum Key Distribution Based on EPR Entanglement.

    Science.gov (United States)

    Li, Jian; Li, Na; Li, Lei-Lei; Wang, Tao

    2016-06-30

    A novel quantum key distribution protocol is presented, based on entanglement and dense coding and allowing asymptotically secure key distribution. Considering the storage time limit of quantum bits, a grouping quantum key distribution protocol is proposed, which overcomes the vulnerability of first protocol and improves the maneuverability. Moreover, a security analysis is given and a simple type of eavesdropper's attack would introduce at least an error rate of 46.875%. Compared with the "Ping-pong" protocol involving two steps, the proposed protocol does not need to store the qubit and only involves one step.

  10. STEP and fundamental physics

    Science.gov (United States)

    Overduin, James; Everitt, Francis; Worden, Paul; Mester, John

    2012-09-01

    The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's equivalence principle from their present sensitivity of two parts in 1013 to one part in 1018 through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status and its potential implications for fundamental physics. Equivalence is at the heart of general relativity, our governing theory of gravity and violations are expected in most attempts to unify this theory with the other fundamental interactions of physics, as well as in many theoretical explanations for the phenomenon of dark energy in cosmology. Detection of such a violation would be equivalent to the discovery of a new force of nature. A null result would be almost as profound, pushing upper limits on any coupling between standard-model fields and the new light degrees of freedom generically predicted by these theories down to unnaturally small levels.

  11. STEP and fundamental physics

    International Nuclear Information System (INIS)

    Overduin, James; Everitt, Francis; Worden, Paul; Mester, John

    2012-01-01

    The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's equivalence principle from their present sensitivity of two parts in 10 13 to one part in 10 18 through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status and its potential implications for fundamental physics. Equivalence is at the heart of general relativity, our governing theory of gravity and violations are expected in most attempts to unify this theory with the other fundamental interactions of physics, as well as in many theoretical explanations for the phenomenon of dark energy in cosmology. Detection of such a violation would be equivalent to the discovery of a new force of nature. A null result would be almost as profound, pushing upper limits on any coupling between standard-model fields and the new light degrees of freedom generically predicted by these theories down to unnaturally small levels. (paper)

  12. Interministerial decree of 10 February 1988 fixing the derived limits of the air concentration and the annual intake limit and the values of the quality factor and the neutron fluence rate

    International Nuclear Information System (INIS)

    1988-01-01

    This decree establishes the derived concentration limits in the air and annual inhalation limits for the radioisotopes and the values of the quality factors and the conversion factors fluence/dose equivalent for neutrons and protons

  13. Work to save dose: contrasting effective dose rates from radon exposure in workplaces and residences against the backdrop of public and occupational limits

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey J [Los Alamos National Laboratory; Mcnaughton, Michael W [Los Alamos National Laboratory

    2009-01-01

    Office workers are exposed to radon while at work and at home. Though there has been a multitude of studies reporting the measurements of radon concentrations and potential lung and effective doses associated with radon and progeny exposure in homes, similar studies on the concentrations and subsequent effective dose rates in the non-mine workplaces are lacking. Additionally, there are few, if any, comparative analyses of radon exposures at more 'typical' workplace with residential exposures within the same county. The purposes of this study were to measure radon concentrations in office and residential spaces in the same county and explore the radiation dose implications. Sixty-five track-etch detectors were deployed in office spaces and 47 were deployed in residences, all within Los Alamos County, New Mexico, USA. The sampling periods for these measurements were generally about three months. The measured concentrations were used to calculate and compare effective dose rates resulting from exposure while at work and at home. Results showed that full-time office workers receive on average about 8 times greater exposure at home than while in the office (2.3 mSv yr-! versus 0.3 mSv yr-!). The estimated effective dose rate for a more homebound person was about 3 mSv yr-!. Estimating effective doses from background radon exposure in the same county as Los Alamos National Laboratory, with thousands of'radiological workers,' highlights interesting contrasts in radiation protection standards that span public and occupational settings. For example, the effective dose rate from background radon exposure in unregulated office spaces ranged up to 1.1 mSv yr-!, which is similar to the 1 mSv yr-! threshold for regulation ofa 'radiological worker,' as defined in the Department of Energy regulations for occupational exposure. Additionally, the estimated average effective dose total of> 3 mSv yf! from radon background exposure in homes stands in

  14. Work to save dose: contrasting effective dose rates from radon exposure in workplaces and residences against the backdrop of public and occupational limits

    International Nuclear Information System (INIS)

    Whicker, Jeffrey J.; Mcnaughton, Michael W.

    2009-01-01

    Office workers are exposed to radon while at work and at home. Though there has been a multitude of studies reporting the measurements of radon concentrations and potential lung and effective doses associated with radon and progeny exposure in homes, similar studies on the concentrations and subsequent effective dose rates in the non-mine workplaces are lacking. Additionally, there are few, if any, comparative analyses of radon exposures at more 'typical' workplace with residential exposures within the same county. The purposes of this study were to measure radon concentrations in office and residential spaces in the same county and explore the radiation dose implications. Sixty-five track-etch detectors were deployed in office spaces and 47 were deployed in residences, all within Los Alamos County, New Mexico, USA. The sampling periods for these measurements were generally about three months. The measured concentrations were used to calculate and compare effective dose rates resulting from exposure while at work and at home. Results showed that full-time office workers receive on average about 8 times greater exposure at home than while in the office (2.3 mSv yr- versus 0.3 mSv yr-). The estimated effective dose rate for a more homebound person was about 3 mSv yr-. Estimating effective doses from background radon exposure in the same county as Los Alamos National Laboratory, with thousands of'radiological workers,' highlights interesting contrasts in radiation protection standards that span public and occupational settings. For example, the effective dose rate from background radon exposure in unregulated office spaces ranged up to 1.1 mSv yr-, which is similar to the 1 mSv yr- threshold for regulation ofa 'radiological worker,' as defined in the Department of Energy regulations for occupational exposure. Additionally, the estimated average effective dose total of> 3 mSv yf from radon background exposure in homes stands in contrast to the 0.1 mSv yr- air pathway

  15. Recurrence rate and need for reoperation after surgery with or without internal limiting membrane removal for the treatment of the epiretinal membrane.

    Science.gov (United States)

    De Novelli, Fernando José; Goldbaum, Mauro; Monteiro, Mario Luiz Ribeiro; Aggio, Fabio Bom; Nóbrega, Mario Junqueira; Takahashi, Walter Yukihiko

    2017-01-01

    To compare the recurrence rate and need for reoperation after epiretinal membrane surgery with and without removal of the internal limiting membrane. In this retrospective study, 125 patients operated for epiretinal membrane removal were evaluated, with a minimum 6-month follow-up. Removal of the epiretinal membrane (ERM) was performed in 78 patients, while 47 had removal of the epiretinal membrane associated with internal limiting membrane peeling (ERM + ILM). The mean age in the ERM group was 65.8 years old, ranging from 41 to 80 years old. In the ERM + ILM group, the mean age was 67.2 years old, ranging from 52 to 82 years old. The mean preoperative visual acuity in the ERM group was 20/80p, and in the ERM + ILM group, it was 20/80. The mean postoperative visual acuity in both groups was 20/30. The mean preoperative macular thickness in the ERM group was 467 µm ranging from 281 to 663 µm; in the ERM + ILM group, the preoperative macular thickness was 497 µm, ranging from 172 to 798 µm. After surgery, a reduction in macular thickness was observed in both groups. In the ERM group, the mean macular thickness reduction was 361 ± 101. µm, whereas in the ERM + ILM group, it was 367 ± 75.2 µm. Twenty-two patients presented with a recurrence of epiretinal membrane, of which 16 (20.5%) were from the ERM group and 6 (12.8%) were from the ERM + ILM group (p = 0.39); one patient (2%) was retreated in the ERM + ILM group, whereas 5 patients (6%) where retreated in the ERM group. We postulate that ILM peeling for the treatment of epiretinal membrane is not a relevant factor either for visual recovery or macular thickness reduction, but it may reduce the recurrence and reoperation rate.

  16. Step by Step Microsoft Office Visio 2003

    CERN Document Server

    Lemke, Judy

    2004-01-01

    Experience learning made easy-and quickly teach yourself how to use Visio 2003, the Microsoft Office business and technical diagramming program. With STEP BY STEP, you can take just the lessons you need, or work from cover to cover. Either way, you drive the instruction-building and practicing the skills you need, just when you need them! Produce computer network diagrams, organization charts, floor plans, and moreUse templates to create new diagrams and drawings quicklyAdd text, color, and 1-D and 2-D shapesInsert graphics and pictures, such as company logosConnect shapes to create a basic f

  17. Chloroplast SRP43 acts as a chaperone for glutamyl-tRNA reductase, the rate-limiting enzyme in tetrapyrrole biosynthesis.

    Science.gov (United States)

    Wang, Peng; Liang, Fu-Cheng; Wittmann, Daniel; Siegel, Alex; Shan, Shu-Ou; Grimm, Bernhard

    2018-04-10

    Assembly of light-harvesting complexes requires synchronization of chlorophyll (Chl) biosynthesis with biogenesis of light-harvesting Chl a/b-binding proteins (LHCPs). The chloroplast signal recognition particle (cpSRP) pathway is responsible for transport of nucleus-encoded LHCPs in the stroma of the plastid and their integration into the thylakoid membranes. Correct folding and assembly of LHCPs require the incorporation of Chls, whose biosynthesis must therefore be precisely coordinated with membrane insertion of LHCPs. How the spatiotemporal coordination between the cpSRP machinery and Chl biosynthesis is achieved is poorly understood. In this work, we demonstrate a direct interaction between cpSRP43, the chaperone that mediates LHCP targeting and insertion, and glutamyl-tRNA reductase (GluTR), a rate-limiting enzyme in tetrapyrrole biosynthesis. Concurrent deficiency for cpSRP43 and the GluTR-binding protein (GBP) additively reduces GluTR levels, indicating that cpSRP43 and GBP act nonredundantly to stabilize GluTR. The substrate-binding domain of cpSRP43 binds to the N-terminal region of GluTR, which harbors aggregation-prone motifs, and the chaperone activity of cpSRP43 efficiently prevents aggregation of these regions. Our work thus reveals a function of cpSRP43 in Chl biosynthesis and suggests a striking mechanism for posttranslational coordination of LHCP insertion with Chl biosynthesis.

  18. Free Modal Algebras Revisited: The Step-by-Step Method

    NARCIS (Netherlands)

    Bezhanishvili, N.; Ghilardi, Silvio; Jibladze, Mamuka

    2012-01-01

    We review the step-by-step method of constructing finitely generated free modal algebras. First we discuss the global step-by-step method, which works well for rank one modal logics. Next we refine the global step-by-step method to obtain the local step-by-step method, which is applicable beyond

  19. Diabetes PSA (:30) Step By Step

    Centers for Disease Control (CDC) Podcasts

    2009-10-24

    First steps to preventing diabetes. For Hispanic and Latino American audiences.  Created: 10/24/2009 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 10/24/2009.

  20. Diabetes PSA (:60) Step By Step

    Centers for Disease Control (CDC) Podcasts

    2009-10-24

    First steps to preventing diabetes. For Hispanic and Latino American audiences.  Created: 10/24/2009 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 10/24/2009.

  1. Results of Attempts to Prevent Departure and/or Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting in Highly-Augmented Fighter Flight Control Systems (HAVE FILTER)

    National Research Council Canada - National Science Library

    Chapa, Michael

    1999-01-01

    The objective of this effort was to evaluate the effects of software rate limiting the pilot command with and without a software pre-filter on a highly-augmented fighter aircraft flight control system...

  2. Step-by-step phacoemulsification training program for ophthalmology residents

    Directory of Open Access Journals (Sweden)

    Wang Yulan

    2013-01-01

    Full Text Available Aims: The aim was to analyze the learning curve of phacoemulsification (phaco performed by residents without experience in performing extra-capsular cataract extraction (ECCE in a step-by-step training program (SBSTP. Materials and Methods: Consecutive surgical records of phaco performed from March 2009 to Sept 2011 by four residents without previous ECCE experience were retrospectively reviewed. The completion rate of the first 30 procedures by each resident was calculated. The main intraoperative phaco parameter records for the first 30 surgeries by each resident were compared with those for their last 30 surgeries. Intraoperative complications in the residents′ procedures were also recorded and analyzed. Results: A total of 1013 surgeries were performed by residents. The completion rate for the first 30 phaco procedures was 79.2 μ 5.8%. The main reasons for halting the procedure were as follows: Anterior capsule tear, inability to crack the nucleus, and posterior capsular rupture during phaco or cortex removal. Cumulative dissipated energy of phaco power used during the surgeries was significantly less in the last 30 cases compared with the first 30 cases (30.10 μ 17.58 vs. 55.41 μ 37.59, P = 0.021. Posterior capsular rupture rate was 2.5 μ 1.2% in total (10.8 μ 4.2% in the first 30 cases and 1.7 μ 1.9% in the last 30 cases, P = 0.008; a statistically significant difference. Conclusion:The step-by-step training program might be a necessary process for a resident to transit from dependence to a self-supported operator. It is also an essential middle step between wet lab training to performing the entire phaco procedure on the patient both effectively and safely.

  3. Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension.

    Science.gov (United States)

    Manela, Neta; Oliva, Moran; Ovadia, Rinat; Sikron-Persi, Noga; Ayenew, Biruk; Fait, Aaron; Galili, Gad; Perl, Avichai; Weiss, David; Oren-Shamir, Michal

    2015-01-01

    Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA) pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG (*)) of the shikimate pathway under a constitutive promoter. The presence of AroG(*) protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG (*) transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids, and phenylpropanoid pathways showed that transcription was not affected by AroG (*). This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG(*) cells, and the relative frequencies of the different anthocyanins changed as well.

  4. Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension

    Directory of Open Access Journals (Sweden)

    Neta eManela

    2015-07-01

    Full Text Available Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG* of the shikimate pathway under a constitutive promoter. The presence of AroG* protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG* transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids and phenylpropanoid pathways showed that transcription was not affected by AroG*. This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG* cells, and the relative frequencies of the different anthocyanins changed as

  5. A conserved degron containing an amphipathic helix regulates the cholesterol-mediated turnover of human squalene monooxygenase, a rate-limiting enzyme in cholesterol synthesis.

    Science.gov (United States)

    Chua, Ngee Kiat; Howe, Vicky; Jatana, Nidhi; Thukral, Lipi; Brown, Andrew J

    2017-12-08

    Cholesterol biosynthesis in the endoplasmic reticulum (ER) is tightly controlled by multiple mechanisms to regulate cellular cholesterol levels. Squalene monooxygenase (SM) is the second rate-limiting enzyme in cholesterol biosynthesis and is regulated both transcriptionally and post-translationally. SM undergoes cholesterol-dependent proteasomal degradation when cholesterol is in excess. The first 100 amino acids of SM (designated SM N100) are necessary for this degradative process and represent the shortest cholesterol-regulated degron identified to date. However, the fundamental intrinsic characteristics of this degron remain unknown. In this study, we performed a series of deletions, point mutations, and domain swaps to identify a 12-residue region (residues Gln-62-Leu-73), required for SM cholesterol-mediated turnover. Molecular dynamics and circular dichroism revealed an amphipathic helix within this 12-residue region. Moreover, 70% of the variation in cholesterol regulation was dependent on the hydrophobicity of this region. Of note, the earliest known Doa10 yeast degron, Deg1, also contains an amphipathic helix and exhibits 42% amino acid similarity with SM N100. Mutating SM residues Phe-35/Ser-37/Leu-65/Ile-69 into alanine, based on the key residues in Deg1, blunted SM cholesterol-mediated turnover. Taken together, our results support a model whereby the amphipathic helix in SM N100 attaches reversibly to the ER membrane depending on cholesterol levels; with excess, the helix is ejected and unravels, exposing a hydrophobic patch, which then serves as a degradation signal. Our findings shed new light on the regulation of a key cholesterol synthesis enzyme, highlighting the conservation of critical degron features from yeast to humans. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Deatherage Kaiser, Brooke L [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-31

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in. × 2 in.) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results will be discussed in a subsequent report.

  7. A review of data on the effects of low and low dose-rate radiation with special reference to the dose limit problem

    International Nuclear Information System (INIS)

    Matsudaira, Hiromichi

    1977-01-01

    This is a review of data pertaining to detection and quantification of the effects after exposure to low LET radiations delivered at low and low dose-rate, i.e., at a level of maximum permissible dose for the radiation workers, on experimental materials ranging from plant to rodents and on some human populations. Irradiation at a dose of a few rad is reported to induce mutation or malignant transformation in some selected model systems, with a linear dose-effect relationship. Moreover, the incidence of the chromosome aberrations in spermatocytes is reported to be elevated in the scorpiones (Tityus bahiensis) collected in a region of high natural background radiations (several rem/year). An increase in the incidence of childhood malignancies is reported among children exposed in utero to diagnostic X-rays. Appreciable increase in the incidence of genetic diseases due possibly to chromosome aberrations is also reported among population living in a region of high natural background radiations. Points are raised and discussed as to the interpretation and particularly application of these data to the estimation of somatic and genetic risks of human population from man-made radiations. Recent attempts of risk-benefit analysis with populations subjected to mass X-ray examination of the chest and stomac are referred to. Since we are unaware of the actual injuries due to the exposure even at the level of radiation workers (5 rem/year), it is out of the capacity of a biologist to afford the basis for the decision of limiting the exposure of general population due to the light water reactor operation to 5 mrem/year. (auth.)

  8. Recovery Efficiency, False Negative Rate, and Limit of Detection Performance of a Validated Macrofoam-Swab Sampling Method with Low Surface Concentrations of Two Bacillus anthracis Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kaiser, Brooke L. D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sydor, Michael A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Barrett, Christopher A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-16

    The performance of a macrofoam-swab sampling method was evaluated using Bacillus anthracis Sterne (BAS) and Bacillus atrophaeus Nakamura (BG) spores applied at nine low target amounts (2-500 spores) to positive-control plates and test coupons (2 in × 2 in) of four surface materials (glass, stainless steel, vinyl tile, and plastic). Test results from cultured samples were used to evaluate the effects of surrogate, surface concentration, and surface material on recovery efficiency (RE), false negative rate (FNR), and limit of detection. For RE, surrogate and surface material had statistically significant effects, but concentration did not. Mean REs were the lowest for vinyl tile (50.8% with BAS, 40.2% with BG) and the highest for glass (92.8% with BAS, 71.4% with BG). FNR values ranged from 0 to 0.833 for BAS and 0 to 0.806 for BG, with values increasing as concentration decreased in the range tested (0.078 to 19.375 CFU/cm2, where CFU denotes ‘colony forming units’). Surface material also had a statistically significant effect. A FNR-concentration curve was fit for each combination of surrogate and surface material. For both surrogates, the FNR curves tended to be the lowest for glass and highest for vinyl title. The FNR curves for BG tended to be higher than for BAS at lower concentrations, especially for glass. Results using a modified Rapid Viability-Polymerase Chain Reaction (mRV-PCR) analysis method were also obtained. The mRV-PCR results and comparisons to the culture results are discussed in a separate report.

  9. One-step microlithography

    Science.gov (United States)

    Kahlen, Franz-Josef; Sankaranarayanan, Srikanth; Kar, Aravinda

    1997-09-01

    Subject of this investigation is a one-step rapid machining process to create miniaturized 3D parts, using the original sample material. An experimental setup where metal powder is fed to the laser beam-material interaction region has been built. The powder is melted and forms planar, 2D geometries as the substrate is moved under the laser beam in XY- direction. After completing the geometry in the plane, the substrate is displaced in Z-direction, and a new layer of material is placed on top of the just completed deposit. By continuous repetition of this process, 3D parts wee created. In particular, the impact of the focal spot size of the high power laser beam on the smallest achievable structures was investigated. At a translation speed of 51 mm/s a minimum material thickness of 590 micrometers was achieved. Also, it was shown that a small Z-displacement has a negligible influence on the continuity of the material deposition over this power range. A high power CO2 laser was used as energy source, the material powder under investigation was stainless steel SS304L. Helium was used as shield gas at a flow rate of 15 1/min. The incident CO2 laser beam power was varied between 300 W and 400 W, with the laser beam intensity distribute in a donut mode. The laser beam was focused to a focal diameter of 600 (Mu) m.

  10. Breastfeeding Practices and Barriers to Implementing the Ten Steps to Successful Breastfeeding in Mississippi Hospitals.

    Science.gov (United States)

    Alakaam, Amir; Lemacks, Jennifer; Yadrick, Kathleen; Connell, Carol; Choi, Hwanseok Winston; Newman, Ray G

    2018-05-01

    Mississippi has the lowest rates of breastfeeding in the United States at 6 and 12 months. There is growing evidence that the rates and duration of infant breastfeeding improve after hospitals implement the Ten Steps to Successful Breastfeeding; moreover, the Ten Steps approach is considered the standard model for evaluation of breastfeeding practices in birthplaces. Research aim: This study aimed to examine the implementation level of the Ten Steps and identify barriers to implementing the Ten Steps in Mississippi hospitals. A cross-sectional self-report survey was used to answer the research aim. Nurse managers of the birthing and maternity units of all 43 Mississippi hospitals that provided birthing and maternity care were recruited. A response rate of 72% ( N = 31) was obtained. Implementation of the Ten Steps in these hospitals was categorized as low, partial, moderate, or high. The researcher classified implementation in 29% of hospitals as moderate and in 71% as partial. The hospital level of implementation was significantly positively associated with the hospital delivery rate along with the hospital cesarean section rate per year. The main barriers for the implementation process of the Ten Steps reported were resistance to new policies, limited financial and human resources, and lack of support from national and state governments. Breastfeeding practices in Mississippi hospitals need to be improved. New policies need to be established in Mississippi to encourage hospitals to adopt the Ten Steps policies and practice in the maternity and birthing units.

  11. Microsoft Office Word 2007 step by step

    CERN Document Server

    Cox, Joyce

    2007-01-01

    Experience learning made easy-and quickly teach yourself how to create impressive documents with Word 2007. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them!Apply styles and themes to your document for a polished lookAdd graphics and text effects-and see a live previewOrganize information with new SmartArt diagrams and chartsInsert references, footnotes, indexes, a table of contentsSend documents for review and manage revisionsTurn your ideas into blogs, Web pages, and moreYour all-in-one learning experience includes:Files for building sk

  12. Evaluating the Effectiveness of an Antimicrobial Stewardship Program on Reducing the Incidence Rate of Healthcare-Associated Clostridium difficile Infection: A Non-Randomized, Stepped Wedge, Single-Site, Observational Study.

    Science.gov (United States)

    DiDiodato, Giulio; McArthur, Leslie

    2016-01-01

    The incidence rate of healthcare-associated Clostridium difficile infection (HA-CDI) is estimated at 1 in 100 patients. Antibiotic exposure is the most consistently reported risk factor for HA-CDI. Strategies to reduce the risk of HA-CDI have focused on reducing antibiotic utilization. Prospective audit and feedback is a commonly used antimicrobial stewardship intervention (ASi). The impact of this ASi on risk of HA-CDI is equivocal. This study examines the effectiveness of a prospective audit and feedback ASi on reducing the risk of HA-CDI. Single-site, 339 bed community-hospital in Barrie, Ontario, Canada. Primary outcome is HA-CDI incidence rate. Daily prospective and audit ASi is the exposure variable. ASi implemented across 6 wards in a non-randomized, stepped wedge design. Criteria for ASi; any intravenous antibiotic use for ≥ 48 hrs, any oral fluoroquinolone or oral second generation cephalosporin use for ≥ 48 hrs, or any antimicrobial use for ≥ 5 days. HA-CDI cases and model covariates were aggregated by ward, year and month starting September 2008 and ending February 2016. Multi-level mixed effect negative binomial regression analysis was used to model the primary outcome, with intercept and slope coefficients for ward-level random effects estimated. Other covariates tested for inclusion in the final model were derived from previously published risk factors. Deviance residuals were used to assess the model's goodness-of-fit. The dataset included 486 observation periods, of which 350 were control periods and 136 were intervention periods. After accounting for all other model covariates, the estimated overall ASi incidence rate ratio (IRR) was 0.48 (95% 0.30, 0.79). The ASi effect was independent of antimicrobial utilization. The ASi did not seem to reduce the risk of Clostridium difficile infection on the surgery wards (IRR 0.87, 95% CI 0.45, 1.69) compared to the medicine wards (IRR 0.42, 95% CI 0.28, 0.63). The ward-level burden of Clostridium

  13. Evaluating the Effectiveness of an Antimicrobial Stewardship Program on Reducing the Incidence Rate of Healthcare-Associated Clostridium difficile Infection: A Non-Randomized, Stepped Wedge, Single-Site, Observational Study.

    Directory of Open Access Journals (Sweden)

    Giulio DiDiodato

    Full Text Available The incidence rate of healthcare-associated Clostridium difficile infection (HA-CDI is estimated at 1 in 100 patients. Antibiotic exposure is the most consistently reported risk factor for HA-CDI. Strategies to reduce the risk of HA-CDI have focused on reducing antibiotic utilization. Prospective audit and feedback is a commonly used antimicrobial stewardship intervention (ASi. The impact of this ASi on risk of HA-CDI is equivocal. This study examines the effectiveness of a prospective audit and feedback ASi on reducing the risk of HA-CDI.Single-site, 339 bed community-hospital in Barrie, Ontario, Canada. Primary outcome is HA-CDI incidence rate. Daily prospective and audit ASi is the exposure variable. ASi implemented across 6 wards in a non-randomized, stepped wedge design. Criteria for ASi; any intravenous antibiotic use for ≥ 48 hrs, any oral fluoroquinolone or oral second generation cephalosporin use for ≥ 48 hrs, or any antimicrobial use for ≥ 5 days. HA-CDI cases and model covariates were aggregated by ward, year and month starting September 2008 and ending February 2016. Multi-level mixed effect negative binomial regression analysis was used to model the primary outcome, with intercept and slope coefficients for ward-level random effects estimated. Other covariates tested for inclusion in the final model were derived from previously published risk factors. Deviance residuals were used to assess the model's goodness-of-fit.The dataset included 486 observation periods, of which 350 were control periods and 136 were intervention periods. After accounting for all other model covariates, the estimated overall ASi incidence rate ratio (IRR was 0.48 (95% 0.30, 0.79. The ASi effect was independent of antimicrobial utilization. The ASi did not seem to reduce the risk of Clostridium difficile infection on the surgery wards (IRR 0.87, 95% CI 0.45, 1.69 compared to the medicine wards (IRR 0.42, 95% CI 0.28, 0.63. The ward-level burden of

  14. FIRST STEP towards ICF commercialization

    International Nuclear Information System (INIS)

    Saylor, W.W.; Pendergrass, J.H.; Dudziak, D.J.

    1984-01-01

    Production of tritium for weapons and fusion R and D programs and successful development of Inertial Confinement Fusion (ICF) technologies are important national goals. A conceptual design for an ICF facility to meet these goals is presented. FIRST STEP (Fusion, Inertial, Reduced-Requirements Systems Test for Special Nuclear Material, Tritium, and Energy Production) is a concept for a plant to produce SNM, tritium, and energy while serving as a test bed for ICF technology development. A credible conceptual design for an ICF SNM and tritium production facility that competes favorably with fission technology on the bases of cost, production quality, and safety was sought. FIRST STEP is also designed to be an engineering test facility that integrates systems required for an ICF power plant and that is intermediate in scale between proof-of-principle experiment and commercial power plant. FIRST STEP driver and pellet performance requirements are moderate and represent reasonable intermediate goals in an R and D plan for ICF commercialization. Repetition rate requirements for FIRST STEP are similar to those of commercial size plants and FIRST STEP can be used to integrate systems under realistic ICF conditions

  15. Role of step stiffness and kinks in the relaxation of vicinal (001) with zigzag [110] steps

    Science.gov (United States)

    Mahjoub, B.; Hamouda, Ajmi BH.; Einstein, TL.

    2017-08-01

    We present a kinetic Monte Carlo study of the relaxation dynamics and steady state configurations of 〈110〉 steps on a vicinal (001) simple cubic surface. This system is interesting because 〈110〉 (fully kinked) steps have different elementary excitation energetics and favor step diffusion more than 〈100〉 (nominally straight) steps. In this study we show how this leads to different relaxation dynamics as well as to different steady state configurations, including that 2-bond breaking processes are rate determining for 〈110〉 steps in contrast to 3-bond breaking processes for 〈100〉-steps found in previous work [Surface Sci. 602, 3569 (2008)]. The analysis of the terrace-width distribution (TWD) shows a significant role of kink-generation-annihilation processes during the relaxation of steps: the kinetic of relaxation, toward the steady state, is much faster in the case of 〈110〉-zigzag steps, with a higher standard deviation of the TWD, in agreement with a decrease of step stiffness due to orientation. We conclude that smaller step stiffness leads inexorably to faster step dynamics towards the steady state. The step-edge anisotropy slows the relaxation of steps and increases the strength of step-step effective interactions.

  16. Rapid decay of vacancy islands at step edges on Ag(111): step orientation dependence

    International Nuclear Information System (INIS)

    Shen, Mingmin; Thiel, P A; Jenks, Cynthia J; Evans, J W

    2010-01-01

    Previous work has established that vacancy islands or pits fill much more quickly when they are in contact with a step edge, such that the common boundary is a double step. The present work focuses on the effect of the orientation of that step, with two possibilities existing for a face centered cubic (111) surface: A- and B-type steps. We find that the following features can depend on the orientation: (1) the shapes of islands while they shrink; (2) whether the island remains attached to the step edge; and (3) the rate of filling. The first two effects can be explained by the different rates of adatom diffusion along the A- and B-steps that define the pit, enhanced by the different filling rates. The third observation-the difference in the filling rate itself-is explained within the context of the concerted exchange mechanism at the double step. This process is facile at all regular sites along B-steps, but only at kink sites along A-steps, which explains the different rates. We also observe that oxygen can greatly accelerate the decay process, although it has no apparent effect on an isolated vacancy island (i.e. an island that is not in contact with a step).

  17. Delivering stepped care: an analysis of implementation in routine practice

    Directory of Open Access Journals (Sweden)

    Richards David A

    2012-01-01

    Full Text Available Abstract Background In the United Kingdom, clinical guidelines recommend that services for depression and anxiety should be structured around a stepped care model, where patients receive treatment at different 'steps,' with the intensity of treatment (i.e., the amount and type increasing at each step if they fail to benefit at previous steps. There are very limited data available on the implementation of this model, particularly on the intensity of psychological treatment at each step. Our objective was to describe patient pathways through stepped care services and the impact of this on patient flow and management. Methods We recorded service design features of four National Health Service sites implementing stepped care (e.g., the types of treatments available and their links with other treatments, together with the actual treatments received by individual patients and their transitions between different treatment steps. We computed the proportions of patients accessing, receiving, and transiting between the various steps and mapped these proportions visually to illustrate patient movement. Results We collected throughput data on 7,698 patients referred. Patient pathways were highly complex and very variable within and between sites. The ratio of low (e.g., self-help to high-intensity (e.g., cognitive behaviour therapy treatments delivered varied between sites from 22:1, through 2.1:1, 1.4:1 to 0.5:1. The numbers of patients allocated directly to high-intensity treatment varied from 3% to 45%. Rates of stepping up from low-intensity treatment to high-intensity treatment were less than 10%. Conclusions When services attempt to implement the recommendation for stepped care in the National Institute for Health and Clinical Excellence guidelines, there were significant differences in implementation and consequent high levels of variation in patient pathways. Evaluations driven by the principles of implementation science (such as targeted planning

  18. 40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

    Science.gov (United States)

    2010-07-01

    ... Rate With Add-on Controls Option or the Control Efficiency/Outlet Concentration Compliance Option 4... Add-on Controls Option or the Control Efficiency/Outlet Concentration Compliance Option If you are... volumetric flow rate at a location upstream of the control device, or duct static pressure at a location...

  19. Step-by-step cyclic processes scheduling

    DEFF Research Database (Denmark)

    Bocewicz, G.; Nielsen, Izabela Ewa; Banaszak, Z.

    2013-01-01

    Automated Guided Vehicles (AGVs) fleet scheduling is one of the big problems in Flexible Manufacturing System (FMS) control. The problem is more complicated when concurrent multi-product manufacturing and resource deadlock avoidance policies are considered. The objective of the research is to pro......Automated Guided Vehicles (AGVs) fleet scheduling is one of the big problems in Flexible Manufacturing System (FMS) control. The problem is more complicated when concurrent multi-product manufacturing and resource deadlock avoidance policies are considered. The objective of the research...... is to provide a declarative model enabling to state a constraint satisfaction problem aimed at AGVs fleet scheduling subject to assumed itineraries of concurrently manufactured product types. In other words, assuming a given layout of FMS’s material handling and production routes of simultaneously manufactured...... orders, the main objective is to provide the declarative framework aimed at conditions allowing one to calculate the AGVs fleet schedule in online mode. An illustrative example of the relevant algebra-like driven step-by-stem cyclic scheduling is provided....

  20. Limited Seed and Seed Yield Response of Calendula to Applied Nitrogen Does Not Justify Risk of Environmental Damage from High Urea Application Rates

    OpenAIRE

    Jane M. F. Johnson; Russ W. Gesch; Nancy W. Barbour

    2018-01-01

    Calendula (Calendula officinalis L.) seed, due to its high calendic acid content, is recognized as a potential environmentally safe substitute for volatile organic compounds. Agronomic guidelines for nitrogen (N) management to produce calendula seed oil on a commercial scale are limited. Post-harvest soil N has the potential to move off-farm and contribute to water quality degradation (e.g., hypoxia in the Gulf of Mexico). Establishing N management guidelines should consider agronomic respons...

  1. Environmental impacts of genetic improvement of growth rate and feed conversion ratio in fish farming under rearing density and nitrogen output limitations

    NARCIS (Netherlands)

    Besson, M.; Aubin, J.; Komen, H.; Poelman, M.; Quillet, E.; Vandeputte, M.; Arendonk, Van J.A.M.; Boer, De I.J.M.

    2016-01-01

    Today, fish farming faces an increasing demand in fish products, but also various environmental challenges. Genetic improvement in growth rate and feed conversion ratio is known to be an efficient way to increase production and increase efficiency in fish farming. The environmental consequences

  2. Analysis of a Farquhar-von Caemmerer-Berry leaf-level photosynthetic rate model for Populus tremuloides in the context of modeling and measurement limitations

    Science.gov (United States)

    K.E. Lenz; G.E. Host; K. Roskoski; A. Noormets; A. Sober; D.F. Karnosky

    2010-01-01

    The balance of mechanistic detail with mathematical simplicity contributes to the broad use of the Farquhar, von Caemmerer and Berry (FvCB) photosynthetic rate model. Here the FvCB model was coupled with a stomatal conductance model to form an [A,gs] model, and parameterized for mature Populus tremuloides leaves under varying CO2...

  3. Response to Jensen et al. : pelvic floor reconstruction with a biological mesh after extralevator abdominoperineal excision leads tolow wound complications and perineal hernia rates with minor movement limitations

    NARCIS (Netherlands)

    Musters, G. D.; Bemelman, W. A.; Tanis, P. J.

    2014-01-01

    Jensen et al describe their experience with reconstruction of the pelvic floor using a biological mesh after extralevator abdominoperineal excision (ELAPE)[1]. The title states that a biological mesh leads to low perineal wound complications and perineal hernia rates. Surprisingly the authors

  4. Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

    KAUST Repository

    Soury, Hamza; Elsawy, Hesham; Alouini, Mohamed-Slim

    2017-01-01

    This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have

  5. A developmental taxonomy of juvenile sex offenders for theory, research, and prevention: the adolescent-limited and the high-rate slow desister

    NARCIS (Netherlands)

    Lussier, P.; van den Berg, C.; Bijleveld, C.; Hendriks, J.

    2012-01-01

    The current study investigates the offending trajectories of juvenile sex offenders (JSOs) across and beyond adolescence. In doing so, the study examines the number, the rate, and the shape of nonsexual and sexual offending trajectories in a sample of JSOs followed retrospectively and prospectively

  6. A Developmental Taxonomy of Juvenile Sex Offenders for Theory, Research, and Prevention: The Adolescent-Limited and the High-Rate Slow Desister

    NARCIS (Netherlands)

    Lussier, P; van den Berg, C.J.W.; Bijleveld, C.C.J.H.; Hendriks, J.

    2012-01-01

    The current study investigates the offending trajectories of juvenile sex offenders (JSOs) across and beyond adolescence. In doing so, the study examines the number, the rate, and the shape of nonsexual and sexual offending trajectories in a sample of JSOs followed retrospectively and prospectively

  7. a metabolic wastage model for the rate-yield trade off

    Indian Academy of Sciences (India)

    A METABOLIC WASTAGE MODEL FOR THE RATE-YIELD TRADE OFF. There is a growth limiting step in which an intermediate metabolite (m) has to hit a target molecule (t). ... D= rate of diffusing out. S= the rate of formation of the metabolite. The equilibrium loss decides the yield. The no. of activated targets decide the rate ...

  8. Analysis of a Farquhar-von Caemmerer-Berry leaf-level photosynthetic rate model for Populus tremuloides in the context of modeling and measurement limitations

    International Nuclear Information System (INIS)

    Lenz, Kathryn E.; Host, George E.; Roskoski, Kyle; Noormets, Asko; Sober, Anu; Karnosky, David F.

    2010-01-01

    The balance of mechanistic detail with mathematical simplicity contributes to the broad use of the Farquhar, von Caemmerer and Berry (FvCB) photosynthetic rate model. Here the FvCB model was coupled with a stomatal conductance model to form an [A,g s ] model, and parameterized for mature Populus tremuloides leaves under varying CO 2 and temperature levels. Data were selected to be within typical forest light, CO 2 and temperature ranges, reducing artifacts associated with data collected at extreme values. The error between model-predicted photosynthetic rate (A) and A data was measured in three ways and found to be up to three times greater for each of two independent data sets than for a base-line evaluation using parameterization data. The evaluation methods used here apply to comparisons of model validation results among data sets varying in number and distribution of data, as well as to performance comparisons of [A,g s ] models differing in internal-process components. - A photosynthetic rate model is parameterized for Populus tremuloides and evaluated based on its ability to predict dependent as well as independent data.

  9. Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers

    Directory of Open Access Journals (Sweden)

    Lara M. Kueppers

    2017-11-01

    Full Text Available Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.

  10. The Seven Step Strategy

    Science.gov (United States)

    Schaffer, Connie

    2017-01-01

    Many well-intended instructors use Socratic or leveled questioning to facilitate the discussion of an assigned reading. While this engages a few students, most can opt to remain silent. The seven step strategy described in this article provides an alternative to classroom silence and engages all students. Students discuss a single reading as they…

  11. Mitigating Satellite-Based Fire Sampling Limitations in Deriving Biomass Burning Emission Rates: Application to WRF-Chem Model Over the Northern sub-Saharan African Region

    Science.gov (United States)

    Wang, Jun; Yue, Yun; Wang, Yi; Ichoku, Charles; Ellison, Luke; Zeng, Jing

    2018-01-01

    Largely used in several independent estimates of fire emissions, fire products based on MODIS sensors aboard the Terra and Aqua polar-orbiting satellites have a number of inherent limitations, including (a) inability to detect fires below clouds, (b) significant decrease of detection sensitivity at the edge of scan where pixel sizes are much larger than at nadir, and (c) gaps between adjacent swaths in tropical regions. To remedy these limitations, an empirical method is developed here and applied to correct fire emission estimates based on MODIS pixel level fire radiative power measurements and emission coefficients from the Fire Energetics and Emissions Research (FEER) biomass burning emission inventory. The analysis was performed for January 2010 over the northern sub-Saharan African region. Simulations from WRF-Chem model using original and adjusted emissions are compared with the aerosol optical depth (AOD) products from MODIS and AERONET as well as aerosol vertical profile from CALIOP data. The comparison confirmed an 30-50% improvement in the model simulation performance (in terms of correlation, bias, and spatial pattern of AOD with respect to observations) by the adjusted emissions that not only increases the original emission amount by a factor of two but also results in the spatially continuous estimates of instantaneous fire emissions at daily time scales. Such improvement cannot be achieved by simply scaling the original emission across the study domain. Even with this improvement, a factor of two underestimations still exists in the modeled AOD, which is within the current global fire emissions uncertainty envelope.

  12. Linear step drive

    International Nuclear Information System (INIS)

    Haniger, L.; Elger, R.; Kocandrle, L.; Zdebor, J.

    1986-01-01

    A linear step drive is described developed in Czechoslovak-Soviet cooperation and intended for driving WWER-1000 control rods. The functional principle is explained of the motor and the mechanical and electrical parts of the drive, power control, and the indicator of position are described. The motor has latches situated in the reactor at a distance of 3 m from magnetic armatures, it has a low structural height above the reactor cover, which suggests its suitability for seismic localities. Its magnetic circuits use counterpoles; the mechanical shocks at the completion of each step are damped using special design features. The position indicator is of a special design and evaluates motor position within ±1% of total travel. A drive diagram and the flow chart of both the control electronics and the position indicator are presented. (author) 4 figs

  13. Computational Abstraction Steps

    DEFF Research Database (Denmark)

    Thomsen, Lone Leth; Thomsen, Bent; Nørmark, Kurt

    2010-01-01

    and class instantiations. Our teaching experience shows that many novice programmers find it difficult to write programs with abstractions that materialise to concrete objects later in the development process. The contribution of this paper is the idea of initiating a programming process by creating...... or capturing concrete values, objects, or actions. As the next step, some of these are lifted to a higher level by computational means. In the object-oriented paradigm the target of such steps is classes. We hypothesise that the proposed approach primarily will be beneficial to novice programmers or during...... the exploratory phase of a program development process. In some specific niches it is also expected that our approach will benefit professional programmers....

  14. Step 3: Manage Your Diabetes

    Science.gov (United States)

    ... please turn JavaScript on. Feature: Type 2 Diabetes Step 3: Manage Your Diabetes Past Issues / Fall 2014 ... 2 Diabetes" Articles Diabetes Is Serious But Manageable / Step 1: Learn About Diabetes / Step 2: Know Your ...

  15. All-cause mortality rates and home deaths decreased in children with life-limiting diagnoses in Denmark between 1994 and 2014

    DEFF Research Database (Denmark)

    Lykke, Camilla; Ekholm, Ola; Schmiegelow, Kjeld

    2018-01-01

    %). The relative proportion of hospital deaths increased, while home deaths decreased. CONCLUSION: All-cause mortality rate decreased markedly, and the relative proportion of hospital deaths increased. The results may reflect more aggressive and effective treatment attempts to save lives, but some terminally ill...... deaths. The decline in infant mortality (26%) primarily reflected fewer deaths due to congenital malformations and chromosomal abnormalities (68%) and perinatal deaths (30%). In children aged one year to 17 years, the substantial decrease (65%) was due to external causes (75%) and neoplasms (57......AIM: Specialised paediatric palliative care has not previously been a priority in Denmark. The aim of this study was to support its development and organisation, by examining why and where children died using official national data for 1994-2014. METHODS: We obtained data on 9462 children who died...

  16. Further limitations on nuclear testing

    International Nuclear Information System (INIS)

    Brown, P.S.

    1991-11-01

    This document addresses a number of subjects related to further constraints on nuclear testing, briefly discussing each of the following topics: the current political situation, the kinds of steps that might next be taken in test limitations and the impacts of further testing limits, the need for a test ban readiness program, some issues related to verification, and the possibility of confidence building measures as alternative, or near-term, steps to further test limitations

  17. Limiting enclosures. Method of control of the leak rate per hour. Enclosures of classes 1 and 2. Method of measurement of the increase of the oxygen titre in volume

    International Nuclear Information System (INIS)

    1984-07-01

    The present standard can be applied to limiting enclosures working under depression or overpressure. It can be applied to limiting enclosures used for works on radioactive or toxic materials. The leak rate per hour is -2 h -1 . The measuring method uses oxygen determination after the enclusore is filled with an inert gas. The influence of pressure and temperature are analysed. The measurement installation and its operating way are presented; the accuracy of the method given. This standard supersedes the experimental standard of December 1982 [fr

  18. Reduction of the hydraulic retention time at constant high organic loading rate to reach the microbial limits of anaerobic digestion in various reactor systems.

    Science.gov (United States)

    Ziganshin, Ayrat M; Schmidt, Thomas; Lv, Zuopeng; Liebetrau, Jan; Richnow, Hans Hermann; Kleinsteuber, Sabine; Nikolausz, Marcell

    2016-10-01

    The effects of hydraulic retention time (HRT) reduction at constant high organic loading rate on the activity of hydrogen-producing bacteria and methanogens were investigated in reactors digesting thin stillage. Stable isotope fingerprinting was additionally applied to assess methanogenic pathways. Based on hydA gene transcripts, Clostridiales was the most active hydrogen-producing order in continuous stirred tank reactor (CSTR), fixed-bed reactor (FBR) and anaerobic sequencing batch reactor (ASBR), but shorter HRT stimulated the activity of Spirochaetales. Further decreasing HRT diminished Spirochaetales activity in systems with biomass retention. Based on mcrA gene transcripts, Methanoculleus and Methanosarcina were the predominantly active in CSTR and ASBR, whereas Methanosaeta and Methanospirillum activity was more significant in stably performing FBR. Isotope values indicated the predominance of aceticlastic pathway in FBR. Interestingly, an increased activity of Methanosaeta was observed during shortening HRT in CSTR and ASBR despite high organic acids concentrations, what was supported by stable isotope data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. A step-defined sedentary lifestyle index: <5000 steps/day.

    Science.gov (United States)

    Tudor-Locke, Catrine; Craig, Cora L; Thyfault, John P; Spence, John C

    2013-02-01

    Step counting (using pedometers or accelerometers) is widely accepted by researchers, practitioners, and the general public. Given the mounting evidence of the link between low steps/day and time spent in sedentary behaviours, how few steps/day some populations actually perform, and the growing interest in the potentially deleterious effects of excessive sedentary behaviours on health, an emerging question is "How many steps/day are too few?" This review examines the utility, appropriateness, and limitations of using a reoccurring candidate for a step-defined sedentary lifestyle index: 10 000) to lower (sedentary lifestyle index for adults is appropriate for researchers and practitioners and for communicating with the general public. There is little evidence to advocate any specific value indicative of a step-defined sedentary lifestyle index in children and adolescents.

  20. Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

    Science.gov (United States)

    J.S. Norman; J.E. Barrett

    2014-01-01

    Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

  1. Stepping Stones through Time

    Directory of Open Access Journals (Sweden)

    Emily Lyle

    2012-03-01

    Full Text Available Indo-European mythology is known only through written records but it needs to be understood in terms of the preliterate oral-cultural context in which it was rooted. It is proposed that this world was conceptually organized through a memory-capsule consisting of the current generation and the three before it, and that there was a system of alternate generations with each generation taking a step into the future under the leadership of a white or red king.

  2. SYSTEMATIZATION OF THE BASIC STEPS OF THE STEP-AEROBICS

    Directory of Open Access Journals (Sweden)

    Darinka Korovljev

    2011-03-01

    Full Text Available Following the development of the powerful sport industry, in front of us appeared a lot of new opportunities for creating of the new programmes of exercising with certain requisites. One of such programmes is certainly step-aerobics. Step-aerobics can be defined as a type of aerobics consisting of the basic aerobic steps (basic steps applied in exercising on stepper (step bench, with a possibility to regulate its height. Step-aerobics itself can be divided into several groups, depending on the following: type of music, working methods and adopted knowledge of the attendants. In this work, the systematization of the basic steps in step-aerobics was made on the basis of the following criteria: steps origin, number of leg motions in stepping and relating the body support at the end of the step. Systematization of the basic steps of the step-aerobics is quite significant for making a concrete review of the existing basic steps, thus making creation of the step-aerobics lesson easier

  3. Electric-current-induced step bunching on Si(111)

    International Nuclear Information System (INIS)

    Homma, Yoshikazu; Aizawa, Noriyuki

    2000-01-01

    We experimentally investigated step bunching induced by direct current on vicinal Si(111)'1x1' surfaces using scanning electron microscopy and atomic force microscopy. The scaling relation between the average step spacing l b and the number of steps N in a bunch, l b ∼N -α , was determined for four step-bunching temperature regimes above the 7x7-'1x1' transition temperature. The step-bunching rate and scaling exponent differ between neighboring step-bunching regimes. The exponent α is 0.7 for the two regimes where the step-down current induces step bunching (860-960 and 1210-1300 deg. C), and 0.6 for the two regimes where the step-up current induces step bunching (1060-1190 and >1320 deg. C). The number of single steps on terraces also differs in each of the four temperature regimes. For temperatures higher than 1280 deg. C, the prefactor of the scaling relation increases, indicating an increase in step-step repulsion. The scaling exponents obtained agree reasonably well with those predicted by theoretical models. However, they give unrealistic values for the effective charges of adatoms for step-up-current-induced step bunching when the 'transparent' step model is used

  4. Warming and organic matter sources impact the proportion of dissolved to total activities in marine extracellular enzymatic rates

    KAUST Repository

    Baltar, Federico; Moran, Xose Anxelu G.; Lø nborg, Christian

    2017-01-01

    Extracellular enzymatic activities (EEAs) are the rate-limiting step in the degradation of organic matter. Extracellular enzymes can be found associated to cells or dissolved in the surrounding water. The proportion of cell-free EEA constitutes

  5. Hippocampus discovery First steps

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    Full Text Available The first steps of the discovery, and the main discoverers, of the hippocampus are outlined. Arantius was the first to describe a structure he named "hippocampus" or "white silkworm". Despite numerous controversies and alternate designations, the term hippocampus has prevailed until this day as the most widely used term. Duvernoy provided an illustration of the hippocampus and surrounding structures, considered the first by most authors, which appeared more than one and a half century after Arantius' description. Some authors have identified other drawings and texts which they claim predate Duvernoy's depiction, in studies by Vesalius, Varolio, Willis, and Eustachio, albeit unconvincingly. Considering the definition of the hippocampal formation as comprising the hippocampus proper, dentate gyrus and subiculum, Arantius and Duvernoy apparently described the gross anatomy of this complex. The pioneering studies of Arantius and Duvernoy revealed a relatively small hidden formation that would become one of the most valued brain structures.

  6. Astronomical sketching a step-by-step introduction

    CERN Document Server

    Handy, Richard; Perez, Jeremy; Rix, Erika; Robbins, Sol

    2007-01-01

    This book presents the amateur with fine examples of astronomical sketches and step-by-step tutorials in each medium, from pencil to computer graphics programs. This unique book can teach almost anyone to create beautiful sketches of celestial objects.

  7. Step 1: Learn about Diabetes

    Science.gov (United States)

    ... please turn JavaScript on. Feature: Type 2 Diabetes Step 1: Learn About Diabetes Past Issues / Fall 2014 ... the whole family healthy! Here are four key steps to help you control your diabetes and live ...

  8. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  9. Multiple stage miniature stepping motor

    International Nuclear Information System (INIS)

    Niven, W.A.; Shikany, S.D.; Shira, M.L.

    1981-01-01

    A stepping motor comprising a plurality of stages which may be selectively activated to effect stepping movement of the motor, and which are mounted along a common rotor shaft to achieve considerable reduction in motor size and minimum diameter, whereby sequential activation of the stages results in successive rotor steps with direction being determined by the particular activating sequence followed

  10. Two-Step Amyloid Aggregation: Sequential Lag Phase Intermediates

    Science.gov (United States)

    Castello, Fabio; Paredes, Jose M.; Ruedas-Rama, Maria J.; Martin, Miguel; Roldan, Mar; Casares, Salvador; Orte, Angel

    2017-01-01

    The self-assembly of proteins into fibrillar structures called amyloid fibrils underlies the onset and symptoms of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s. However, the molecular basis and mechanism of amyloid aggregation are not completely understood. For many amyloidogenic proteins, certain oligomeric intermediates that form in the early aggregation phase appear to be the principal cause of cellular toxicity. Recent computational studies have suggested the importance of nonspecific interactions for the initiation of the oligomerization process prior to the structural conversion steps and template seeding, particularly at low protein concentrations. Here, using advanced single-molecule fluorescence spectroscopy and imaging of a model SH3 domain, we obtained direct evidence that nonspecific aggregates are required in a two-step nucleation mechanism of amyloid aggregation. We identified three different oligomeric types according to their sizes and compactness and performed a full mechanistic study that revealed a mandatory rate-limiting conformational conversion step. We also identified the most cytotoxic species, which may be possible targets for inhibiting and preventing amyloid aggregation.

  11. Compensatory stepping responses in individuals with stroke: a pilot study.

    Science.gov (United States)

    Lakhani, Bimal; Mansfield, Avril; Inness, Elizabeth L; McIlroy, William E

    2011-05-01

    Impaired postural control and a high incidence of falls are commonly observed following stroke. Compensatory stepping responses are critical to reactive balance control. We hypothesize that, following a stroke, individuals with unilateral limb dyscontrol will be faced with the unique challenge of controlling such rapid stepping reactions that may eventually be linked to the high rate of falling. The objectives of this exploratory pilot study were to investigate compensatory stepping in individuals poststroke with regard to: (1) choice of initial stepping limb (paretic or non-paretic); (2) step characteristics; and (3) differences in step characteristics when the initial step is taken with the paretic vs. the non-paretic limb. Four subjects following stroke (38-165 days post) and 11 healthy young adults were recruited. Anterior and posterior perturbations were delivered by using a weight drop system. Force plates recorded centre-of-pressure excursion prior to the onset of stepping and step timing. Of the four subjects, three only attempted to step with their non-paretic limb and one stepped with either limb. Time to foot-off was generally slow, whereas step onset time and swing time were comparable to healthy controls. Two of the four subjects executed multistep responses in every trial, and attempts to force stepping with the paretic limb were unsuccessful in three of the four subjects. Despite high clinical balance scores, these individuals with stroke demonstrated impaired compensatory stepping responses, suggesting that current clinical evaluations might not accurately reflect reactive balance control in this population.

  12. One-step reduced kinetics for lean hydrogen-air deflagration

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Galisteo, D.; Sanchez, A.L. [Area de Mecanica de Fluidos, Univ. Carlos III de Madrid, Leganes 28911 (Spain); Linan, A. [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, F.A. [Dept. of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2009-05-15

    A short mechanism consisting of seven elementary reactions, of which only three are reversible, is shown to provide good predictions of hydrogen-air lean-flame burning velocities. This mechanism is further simplified by noting that over a range of conditions of practical interest, near the lean flammability limit all reaction intermediaries have small concentrations in the important thin reaction zone that controls the hydrogen-air laminar burning velocity and therefore follow a steady state approximation, while the main species react according to the global irreversible reaction 2H{sub 2} + O{sub 2} {yields} 2H{sub 2}O. An explicit expression for the non-Arrhenius rate of this one-step overall reaction for hydrogen oxidation is derived from the seven-step detailed mechanism, for application near the flammability limit. The one-step results are used to calculate flammability limits and burning velocities of planar deflagrations. Furthermore, implications concerning radical profiles in the deflagration and reasons for the success of the approximations are clarified. It is also demonstrated that adding only two irreversible direct recombination steps to the seven-step mechanism accurately reproduces burning velocities of the full detailed mechanism for all equivalence ratios at normal atmospheric conditions and that an eight-step detailed mechanism, constructed from the seven-step mechanism by adding to it the fourth reversible shuffle reaction, improves predictions of O and OH profiles. The new reduced-chemistry descriptions can be useful for both analytical and computational studies of lean hydrogen-air flames, decreasing required computation times. (author)

  13. Steps That Count: Physical Activity Recommendations, Brisk Walking, and Steps Per Minute-How Do They Relate?

    NARCIS (Netherlands)

    Pillay, J.; Kolbe-Alexander, T.L.; Proper, K.I.; van Mechelen, W.; Lambert, E.V.

    2014-01-01

    Background: Brisk walking is recommended as a form of health-enhancing physical activity. This study determines the steps/minute rate corresponding to self-paced brisk walking (SPBW); a predicted steps/minute rate for moderate physical activity (MPA) and a comparison of the 2 findings. Methods: A

  14. Quench limits

    International Nuclear Information System (INIS)

    Sapinski, M.

    2012-01-01

    With thirteen beam induced quenches and numerous Machine Development tests, the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these results is taken. The available methods of computation of the quench levels are presented together with dedicated particle shower simulations which are necessary to understand the tests. The future experiments, needed to reach better understanding of quench limits as well as limits for the machine operation are investigated. The possible strategies to set BLM (Beam Loss Monitor) thresholds are discussed. (author)

  15. Calculation of the linear heat generation rates which violate the thermomechanical limit of plastic deformation of the fuel cladding in function of the burn up of a BWR fuel rod type

    International Nuclear Information System (INIS)

    Lucatero, M.A.; Hernandez L, H.

    2003-01-01

    The linear heat generation rates (LHGR) for a BWR type generic fuel rod, as function of the burnup that violate the thermomechanical limit of circumferential plastic deformation of the can (canning) in nominal operation in stationary state of the fuel rod are calculated. The evaluation of the LHGR in function of the burnt of the fuel, is carried out under the condition that the deformation values of the circumferential plastic deformation of the can exceeds in 0.1 the thermomechanical value operation limit of 1%. The results of the calculations are compared with the generation rates of linear operation heat in function of the burnt for this fuel rod type. The calculations are carried out with the FEMAXI-V and RODBURN codes. The results show that for exhibitions or burnt between 0 and 16,000 M Wd/tU a minimum margin of 160.8 W/cm exists among LHGR (439.6 W/cm) operation peak for the given fuel and maximum LHGR of the fuel (calculated) to reach 1.1% of circumferential plastic deformation of the can, for the peak factor of power of 1.40. For burnt of 20,000 MWd/tU and 60,000 MWd/tU exist a margin of 150.3 and 298.6 W/cm, respectively. (Author)

  16. VEIL Surgical Steps.

    Science.gov (United States)

    Raghunath, S K; Nagaraja, H; Srivatsa, N

    2017-03-01

    Inguinal lymphadenectomy remains the standard of care for metastatic nodal disease in cases of penile, urethral, vulval and vaginal cancers. Outcomes, including cure rates and overall and progression-free survivals, have progressively improved in these diseases with extending criteria to offer inguinal lymph node dissection for patients 'at-risk' for metastasis or loco-regional recurrence. Hence, despite declining incidence of advanced stages of these cancers, many patients will still need to undergo lymphadenectomy for optimal oncological outcomes. Inguinal node dissection is a morbid procedure with operative morbidity noted in almost two third of the patients. Video endoscopic inguinal lymphadenectomy (VEIL) was described and currently practiced with proven equivalent oncological outcomes. We describe our technique of VEIL using laparoscopic and robotic access as well as various new surgical strategies.

  17. Steps to Advanced CANDU 600

    International Nuclear Information System (INIS)

    Oh, Yongshick; Brooks, G. L.

    1988-01-01

    The CANDU nuclear power system was developed from merging of AECL heavy water reactor technology with Ontario Hydro electrical power station expertise. The original four units of Ontario Hydro's Pickering Generating Station are the first full-scale commercial application of the CANDU system. AECL and Ontario Hydro then moved to the next evolutionary step, a more advanced larger scale design for four units at the Bruce Generating Station. CANDU 600 followed as a single unit nuclear electric power station design derived from an amalgam of features of the multiple unit Pickering and Bruce designs. The design of the CANDU 600 nuclear steam supply system is based on the Pickering design with improvements derived from the Bruce design. For example, most CANDU 600 auxiliary systems are based on Bruce systems, whereas the fuel handling system is based on the Pickering system. Four CANDU 600 units are in operation, and five are under construction in Romania. For the additional four units at Pickering Generating Station 'B', Ontario Hydro selected a replica of the Pickering 'A' design with limited design changes to maintain a high level of standardization across all eight units. Ontario Hydro applied a similar policy for the additional four units at Bruce Generating Station 'B'. For the four unit Darlington station, Ontario Hydro selected a design based on Bruce with improvements derived from operating experience, the CANDU 600 design and development programs

  18. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  19. Hydrolysis rates of domestic wastewater sludge using biochemical ...

    African Journals Online (AJOL)

    Domestic wastewater treatment can be improved by reducing energy consumption and increasing carbon recovery, which can be achieved using anaerobic digestion of sludge with methane recovery at ambient temperature. Hydrolysis can be a limiting step in anaerobic digestion, and characterisation of hydrolysis rates ...

  20. Strength evaluation code STEP for brittle materials

    International Nuclear Information System (INIS)

    Ishihara, Masahiro; Futakawa, Masatoshi.

    1997-12-01

    In a structural design using brittle materials such as graphite and/or ceramics it is necessary to evaluate the strength of component under complex stress condition. The strength of ceramic materials is said to be influenced by the stress distribution. However, in the structural design criteria simplified stress limits had been adopted without taking account of the strength change with the stress distribution. It is, therefore, important to evaluate the strength of component on the basis of the fracture model for brittle material. Consequently, the strength evaluation program, STEP, on a brittle fracture of ceramic materials based on the competing risk theory had been developed. Two different brittle fracture modes, a surface layer fracture mode dominated by surface flaws and an internal fracture mode by internal flaws, are treated in the STEP code in order to evaluate the strength of brittle fracture. The STEP code uses stress calculation results including complex shape of structures analyzed by the generalized FEM stress analysis code, ABAQUS, so as to be possible to evaluate the strength of brittle fracture for the structures having complicate shapes. This code is, therefore, useful to evaluate the structural integrity of arbitrary shapes of components such as core graphite components in the HTTR, heat exchanger components made of ceramics materials etc. This paper describes the basic equations applying to the STEP code, code system with a combination of the STEP and the ABAQUS codes and the result of the verification analysis. (author)

  1. Step width alters iliotibial band strain during running.

    Science.gov (United States)

    Meardon, Stacey A; Campbell, Samuel; Derrick, Timothy R

    2012-11-01

    This study assessed the effect of step width during running on factors related to iliotibial band (ITB) syndrome. Three-dimensional (3D) kinematics and kinetics were recorded from 15 healthy recreational runners during overground running under various step width conditions (preferred and at least +/- 5% of their leg length). Strain and strain rate were estimated from a musculoskeletal model of the lower extremity. Greater ITB strain and strain rate were found in the narrower step width condition (p running, especially in persons whose running style is characterized by a narrow step width, may be beneficial in the treatment and prevention of running-related ITB syndrome.

  2. Anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure in a single continuously stirred tank reactor process: Limits in co-substrate ratios and organic loading rate.

    Science.gov (United States)

    Rico, Carlos; Muñoz, Noelia; Rico, José Luis

    2015-01-01

    Mesophilic anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure was investigated with the aim of determining the treatment limits in terms of the cheese whey fraction in feed and the organic loading rate. The results of a continuous stirred tank reactor that was operated with a hydraulic retention time of 15.6 days showed that the co-digestion process was possible with a cheese whey fraction as high as 85% in the feed. The efficiency of the process was similar within the range of the 15-85% cheese whey fraction. To study the effect of the increasing loading rate, the HRT was progressively shortened with the 65% cheese whey fraction in the feed. The reactor efficiency dropped as the HRT decreased but enabled a stable operation over 8.7 days of HRT. At these operating conditions, a volumetric methane production rate of 1.37 m(3) CH4 m(-3) d(-1) was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. [First steps in neuronavigation].

    Science.gov (United States)

    Castilla, J M; Martín, V; Fernández-Arconada, O; Delgado, P; Rodríguez-Salazar, A

    2003-10-01

    We try to evaluate the introduction of a neuronavigation system widely used in a neurosurgical department. We analyze the surgical procedures performed since the introduction of a neuronavigator in our hospital, the advantages and the problems related with its use. From 21/12/00 to 31/12/01, 64 cranial and 5 spinal procedures were performed in our centre with the aid of the BrainLAB neuronavigation system. They were 19.37% of the elective surgeries: 45.7% of cranial and 2.8% of spinal procedures. The accuracy of registration was 1.6 mm; the number of trials for registration was 2.8 on average, although in 3 cases it was not possible; there were disarrangements during 9 surgical procedures (two of them after the lesions were reached). Magnetic resonance imaging (MRI) was used in 54 instances, computerized tomography (CT) in 5, fluoroscopy (Rx) in 1, CT plus MRI in 8, CT plus Rx in 1. Since Z-Touch localization system and software was available, it was used exclusively, disregarding the use of external fiducials. In our experience, neuronavigation needs extra time, but it helps in the election of the best position for the surgical approach, reduces the time required for scalp incision and craniotomy planning, and is useful for the opening of the dura and the corticectomy. As the operation proceeds, we found it less truhstworthy and necessary. The Z-touch system frees the imaging from the surgery. Its use in spinal operation is scarce and with limited results in our practice. We found the neuronavigation useful, and we employ it on a regular basis in every cranial procedure whenever it is possible.

  4. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  5. Acomparative Study Comparing Low-dose Step-up Versus Step-down in Polycystic Ovary Syndrome Resistant to Clomiphene

    Directory of Open Access Journals (Sweden)

    S Peivandi

    2010-03-01

    Full Text Available Introduction: Polycystic ovary syndrome(PCOS is one of the most common cause of infertility in women. clomiphene is the first line of treatment. however 20% of patients are resistant to clomiphene. because of follicular hypersensitivity to gonadotropins in pcod, multiple follicular growth and development occurs which is cause of OHSS and multiple pregnancy. Our aim of this random and clinical study was comparation between step-down and low dose step-up methods for induction ovulation in clomiphene resistant. Methods: 60 cases were included 30 women in low-dose step-up group and 30 women in step-down group. In low-dose step-up HMG 75u/d and in step-down HMG 225u/d was started on 3th days of cycle, monitoring with vaginal sonography was done on 8th days of cycle. When follicle with>14 mm in diameter was seen HMG dose was continued in low-dose step-up and was decreased in step-down group. When follicle reached to 18mm in diameter, amp HCG 10000 unit was injected and IUI was performed 36 hours later. Results: Number of HMG ampules, number of follicles> 14mm on the day of HCG injection and level of serum estradiol was greater in low dose step up protocol than step down protocol(p<0/0001. Ovulation rate and pregnancy rate was greater in lowdose step up group than step down group with significant difference (p<0/0001. Conclusion: Our study showed that low-dose step-up regimen with HMG is effective for stimulating ovulation and clinical pregnancy but in view of monofollicular growth, the step down method was more effective and safe. In our study multifolliular growth in step-up method was higher than step-down method. We can predict possibility of Ovarian Hyperstimulation Syndrome syndrome in highly sensitive PCOS patients.

  6. HTSC-Josephson step contacts

    International Nuclear Information System (INIS)

    Herrmann, K.

    1994-03-01

    In this work the properties of josephson step contacts are investigated. After a short introduction into Josephson step contacts the structure, properties and the Josphson contacts of YBa 2 Cu 3 O 7-x high-T c superconductors is presented. The fabrication of HTSC step contacts and the microstructure is discussed. The electric properties of these contacts are measured together with the Josephson emission and the magnetic field dependence. The temperature dependence of the stationary transport properties is given. (WL)

  7. The NIST Step Class Library (Step Into the Future)

    Science.gov (United States)

    1990-09-01

    Figure 6. Excerpt from a STEP exclange file based on the Geometry model 1be NIST STEP Class Libary Page 13 An issue of concern in this...Scheifler, R., Gettys, J., and Newman, P., X Window System: C Library and Protocol Reference. Digital Press, Bedford, Mass, 1988. [Schenck90] Schenck, D

  8. Step-by-Step Visual Manuals: Design and Development

    Science.gov (United States)

    Urata, Toshiyuki

    2004-01-01

    The types of handouts and manuals that are used in technology training vary. Some describe procedures in a narrative way without graphics; some employ step-by-step instructions with screen captures. According to Thirlway (1994), a training manual should be like a tutor that permits a student to learn at his own pace and gives him confidence for…

  9. On the Convexity of Step out - Step in Sequencing Games

    NARCIS (Netherlands)

    Musegaas, Marieke; Borm, Peter; Quant, Marieke

    2016-01-01

    The main result of this paper is the convexity of Step out - Step in (SoSi) sequencing games, a class of relaxed sequencing games first analyzed by Musegaas, Borm, and Quant (2015). The proof makes use of a polynomial time algorithm determining the value and an optimal processing order for an

  10. Valve cam design using numerical step-by-step method

    OpenAIRE

    Vasilyev, Aleksandr; Bakhracheva, Yuliya; Kabore, Ousman; Zelenskiy, Yuriy

    2014-01-01

    This article studies the numerical step-by-step method of cam profile design. The results of the study are used for designing the internal combustion engine valve gear. This method allows to profile the peak efficiency of cams in view of many restrictions, connected with valve gear serviceability and reliability.

  11. Leading Change Step-by-Step: Tactics, Tools, and Tales

    Science.gov (United States)

    Spiro, Jody

    2010-01-01

    "Leading Change Step-by-Step" offers a comprehensive and tactical guide for change leaders. Spiro's approach has been field-tested for more than a decade and proven effective in a wide variety of public sector organizations including K-12 schools, universities, international agencies and non-profits. The book is filled with proven tactics for…

  12. Statistical theory of multi-step compound and direct reactions

    International Nuclear Information System (INIS)

    Feshbach, H.; Kerman, A.; Koonin, S.

    1980-01-01

    The theory of nuclear reactions is extended so as to include a statistical treatment of multi-step processes. Two types are distinguished, the multi-step compound and the multi-step direct. The wave functions for the system are grouped according to their complexity. The multi-step direct process involves explicitly those states which are open, while the multi-step compound involves those which are bound. In addition to the random phase assumption which is applied differently to the multi-step direct and to the multi-step compound cross-sections, it is assumed that the residual interaction will have non-vanishing matrix elements between states whose complexities differ by at most one unit. This is referred to as the chaining hypothesis. Explicit expressions for the double differential cross-section giving the angular distribution and energy spectrum are obtained for both reaction types. The statistical multi-step compound cross-sections are symmetric about 90 0 . The classical statistical theory of nuclear reactions is a special limiting case. The cross-section for the statistical multi-step direct reaction consists of a set of convolutions of single-step direct cross-sections. For the many step case it is possible to derive a diffusion equation in momentum space. Application is made to the reaction 181 Ta(p,n) 181 W using the statistical multi-step compound formalism

  13. A step-by-step framework to assess benefits of established temperate marine protected areas

    Directory of Open Access Journals (Sweden)

    Albrecht Götz

    2013-01-01

    Full Text Available Marine protected areas (MPAs have been advocated as a solution to the challenges of both conservation and modern fishery management, but their application remains controversial, partly because there are only general guidelines for evaluating their effectiveness. We propose a framework to specifically evaluate established MPAs in six steps. We tested the approach by reviewing published research and unpublished information on the Goukamma MPA in the centre of the South African temperate south coast. Information reviewed included effects on the structure of fish populations, catch and abundance indices of fish species, and ecosystem effects. We investigated factors that determine the usefulness of a MPA in fisheries management, including the movement behaviour of adult fishes, larval dispersal and fisher-displacement patterns. We found that differences in the rates of exploitation across the MPA border resulted in differences in abundance, size and condition of the main target species, roman (Chrysoblephus laticeps. The diversity and abundance of non-target fish species, and the composition of the benthic invertebrate community, were affected by the cessation of fishing. The potential for "spillover" of adult roman might be limited to the vicinity of the MPA by their small home range, but there is potential for self-seeding and dispersal of roman eggs and larvae over wider areas. These theoretical considerations were confirmed by an analysis of catch data from before and after MPA implementation. The framework presented here may help to identify and fill gaps in the knowledge of established MPAs along South Africa's temperate south coast.

  14. Running on empty: does mitochondrial DNA mutation limit replicative lifespan in yeast?: Mutations that increase the division rate of cells lacking mitochondrial DNA also extend replicative lifespan in Saccharomyces cerevisiae.

    Science.gov (United States)

    Dunn, Cory D

    2011-10-01

    Mitochondrial DNA (mtDNA) mutations escalate with increasing age in higher organisms. However, it has so far been difficult to experimentally determine whether mtDNA mutation merely correlates with age or directly limits lifespan. A recent study shows that budding yeast can also lose functional mtDNA late in life. Interestingly, independent studies of replicative lifespan (RLS) and of mtDNA-deficient cells show that the same mutations can increase both RLS and the division rate of yeast lacking the mitochondrial genome. These exciting, parallel findings imply a potential causal relationship between mtDNA mutation and replicative senescence. Furthermore, these results suggest more efficient methods for discovering genes that determine lifespan. Copyright © 2011 WILEY Periodicals, Inc.

  15. Ensemble Kalman filtering with one-step-ahead smoothing

    KAUST Repository

    Raboudi, Naila F.; Ait-El-Fquih, Boujemaa; Hoteit, Ibrahim

    2018-01-01

    error statistics. This limits their representativeness of the background error covariances and, thus, their performance. This work explores the efficiency of the one-step-ahead (OSA) smoothing formulation of the Bayesian filtering problem to enhance

  16. Calculation of the linear heat generation rates which violate the thermomechanical limit of plastic deformation of the fuel cladding in function of the burn up of a BWR fuel rod type; Calculo de las razones de generacion de calor lineal que violen el limite termomecanico de deformacion plastica de la camisa en funcion del quemado de una barra combustible tipo BWR

    Energy Technology Data Exchange (ETDEWEB)

    Lucatero, M.A.; Hernandez L, H. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: mal@nuclear.inin.mx

    2003-07-01

    The linear heat generation rates (LHGR) for a BWR type generic fuel rod, as function of the burnup that violate the thermomechanical limit of circumferential plastic deformation of the can (canning) in nominal operation in stationary state of the fuel rod are calculated. The evaluation of the LHGR in function of the burnt of the fuel, is carried out under the condition that the deformation values of the circumferential plastic deformation of the can exceeds in 0.1 the thermomechanical value operation limit of 1%. The results of the calculations are compared with the generation rates of linear operation heat in function of the burnt for this fuel rod type. The calculations are carried out with the FEMAXI-V and RODBURN codes. The results show that for exhibitions or burnt between 0 and 16,000 M Wd/tU a minimum margin of 160.8 W/cm exists among LHGR (439.6 W/cm) operation peak for the given fuel and maximum LHGR of the fuel (calculated) to reach 1.1% of circumferential plastic deformation of the can, for the peak factor of power of 1.40. For burnt of 20,000 MWd/tU and 60,000 MWd/tU exist a margin of 150.3 and 298.6 W/cm, respectively. (Author)

  17. A small step for mankind

    NARCIS (Netherlands)

    Huizing, C.; Koymans, R.L.C.; Kuiper, R.; Dams, D.; Hannemann, U.; Steffen, M.

    2010-01-01

    For many programming languages, the only formal semantics published is an SOS big-step semantics. Such a semantics is not suited for investigations that observe intermediate states, such as invariant techniques. In this paper, a construction is proposed that generates automatically a small-step SOS

  18. Grief: Difficult Times, Simple Steps.

    Science.gov (United States)

    Waszak, Emily Lane

    This guide presents techniques to assist others in coping with the loss of a loved one. Using the language of 9 layperson, the book contains more than 100 tips for caregivers or loved ones. A simple step is presented on each page, followed by reasons and instructions for each step. Chapters include: "What to Say"; "Helpful Things to Do"; "Dealing…

  19. Comparison of false-negative rates and limits of detection following macrofoam-swab sampling of Bacillus anthracis surrogates via Rapid Viability PCR and plate culture

    Energy Technology Data Exchange (ETDEWEB)

    Hutchison, J. R. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA; Piepel, G. F. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA; Amidan, B. G. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA; Hess, B. M. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA; Sydor, M. A. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA; Deatherage Kaiser, B. L. [National Security Directorate, Pacific Northwest National Laboratory, Richland WA USA

    2018-03-13

    Aims: We evaluated the effects of Bacillus anthracis surrogates, low surface concentrations, surface materials, and assay methods on false-negative rate (FNR) and limit of detection (LOD95) for recovering Bacillus spores using a macrofoam-swab sampling procedure. Methods and Results: Bacillus anthracis Sterne or Bacillus atrophaeus Nakamura spores were deposited over a range of low target concentrations (2 – 500 coupon-1) onto glass, stainless steel, vinyl tile, and plastic. Samples were assayed using a modified Rapid Viability-PCR (mRV-PCR) method and the traditional plate culture method to obtain FNR and LOD95 results. Conclusions: Mean FNRs tended to be lower for mRV-PCR compared to culturing, and increased as spore concentration decreased for all surface materials. Surface material, but not B. anthracis surrogate, influenced FNRs with the mRV-PCR method. The mRV-PCR LOD95 was lowest for glass and highest for vinyl tile. LOD95 values overall were lower for mRV-PCR than for the culture method. Significance and Impact of Study: This study adds to the limited data on FNR and LOD95 for mRV-PCR and culturing methods with low concentrations of B. anthracis sampled from various surface materials by the CDC macrofoam-swab method. These are key inputs for planning characterization and clearance studies for low contamination levels of B. anthracis.

  20. Landscape response to tipping points in granite weathering: The case of stepped topography in the Southern Sierra Critical Zone Observatory

    International Nuclear Information System (INIS)

    Jessup, Barbara S.; Jesse Hahm, W.; Miller, Scott N.; Kirchner, James W.; Riebe, Clifford S.

    2011-01-01

    Highlights: → This work tests a decades-old hypothesis in which relief development in the southern Sierra Nevada is attributed to differential weathering of bare and soil-mantled granite. → Terrain analysis shows that the landscape is organized into a sequence of steep steps and gentle treads, consistent with the hypothesis. → Cosmogenic nuclides show that bare granite erodes more slowly than its soil-mantled counterparts, as required by the hypothesis.However, steps erode more quickly than treads, undermining the explanation for the origins of the stepped topography. - Abstract: The dynamics of granitic landscapes are modulated by bimodal weathering, which produces patchy granular soils and expanses of bare rock ranging from meter-scale boulders to mountain-scale domes. We used terrain analysis and with cosmogenic nuclide measurements of erosion rates to quantitatively explore Wahrhaftig's decades-old hypothesis for the development of 'stepped topography' by differential weathering of bare and soil-mantled granite. According to Wahrhaftig's hypothesis, bare granite weathers slower than soil-mantled granite; thus random erosional exposure of bare rock leads to an alternating sequence of steep, slowly weathering bedrock 'steps' and gently sloped, but rapidly weathering, soil-mantled 'treads.' Our investigation focused on the terrain surrounding the Southern Sierra Critical Zone Observatory (CZO), which is underlain by granitic bedrock and lies outside the limits of recent glaciation, in the heart of the stepped topography described by Wahrhaftig. Our digital terrain analysis confirms that steep steps often grade into gentle treads, consistent with Wahrhaftig's hypothesis. However, we observe a mix-and-match of soil and bare rock on treads and steps, contrary to one of the hypothesis' major underpinnings - that bare rock should be much more common on steps than on treads. Moreover, the data show that bare rock is not as common as expected at step tops

  1. AKTIS Nr. 12: To better understand radioactive aerosol deposit in order to better measure it; Radio-induced lesions: a new step towards healing; Modelling the collapse of an immersed grain column; To better model soot deposit; Towards the prediction of the leakage rate of containment enclosures

    International Nuclear Information System (INIS)

    Benderitter, Marc; Perales, Frederic; Monerie, Yann; Maro, Denis; Boyer, Patrick; Lemaitre, Pascal; Porcheron, Emmanuel; Depuydt, Guillaume; Masson, Olivier; Gensdarmes, Francois

    2013-04-01

    This publication presents the main results of researches undertaken by the IRSN in the field of radiation protection, nuclear safety and security. The topics herein addressed are: radio-induced lesions as a new step towards healing (case of injection mesenchymal stem cells for the treatment of induced severe colorectal lesions), the modelling of the collapse of an immersed grain column (to study the nuclear fuel behaviour in an accidental situation through a modelling of fluid-grain interactions), a better understanding of radioactive aerosol deposit (to study particle or aerosol deposits after radioactive releases in the atmosphere in case of accident), a better modelling of soot deposits (in case of fire), the prediction of leakage rates of containment enclosures (ageing phenomena of installations, systems and equipment, with the case of cracks due to material ageing and resulting in confinement losses which could thus be quantified)

  2. 77 FR 38709 - Surface Transportation Environment and Planning Cooperative Research Program (STEP)

    Science.gov (United States)

    2012-06-28

    ... Planning Cooperative Research Program (STEP) AGENCY: Federal Highway Administration (FHWA), DOT. ACTION... Research Program (STEP). The FHWA anticipates that the STEP or a similar program to provide resources for... stakeholders that can leverage limited research funding in the STEP with other stakeholders and partners in...

  3. 75 FR 38605 - Surface Transportation Environment and Planning Cooperative Research Program (STEP)

    Science.gov (United States)

    2010-07-02

    ... Planning Cooperative Research Program (STEP) AGENCY: Federal Highway Administration (FHWA), DOT. ACTION... Research Program (STEP). The FHWA anticipates that the STEP or a similar program to provide resources for... limited research funding in the STEP with other stakeholders and partners in order to increase the total...

  4. 76 FR 50312 - Surface Transportation Environment and Planning Cooperative Research Program (STEP)

    Science.gov (United States)

    2011-08-12

    ... Planning Cooperative Research Program (STEP) AGENCY: Federal Highway Administration (FHWA), DOT. ACTION... Research Program (STEP). The FHWA anticipates that the STEP or a similar program to provide resources for... limited research funding in the STEP with other stakeholders and partners in order to increase the total...

  5. Microprocessor controller for stepping motors

    International Nuclear Information System (INIS)

    Strait, B.G.; Thuot, M.E.

    1977-01-01

    A new concept for digital computer control of multiple stepping motors which operate in a severe electromagnetic pulse environment is presented. The motors position mirrors in the beam-alignment system of a 100-kJ CO 2 laser. An asynchronous communications channel of a computer is used to send coded messages, containing the motor address and stepping-command information, to the stepping-motor controller in a bit serial format over a fiber-optics communications link. The addressed controller responds by transmitting to the computer its address and other motor information, thus confirming the received message. Each controller is capable of controlling three stepping motors. The controller contains the fiber-optics interface, a microprocessor, and the stepping-motor driven circuits. The microprocessor program, which resides in an EPROM, decodes the received messages, transmits responses, performs the stepping-motor sequence logic, maintains motor-position information, and monitors the motor's reference switch. For multiple stepping-motor application, the controllers are connected in a daisy chain providing control of many motors from one asynchronous communications channel of the computer

  6. Adsorption-induced step formation

    DEFF Research Database (Denmark)

    Thostrup, P.; Christoffersen, Ebbe; Lorensen, Henrik Qvist

    2001-01-01

    Through an interplay between density functional calculations, Monte Carlo simulations and scanning tunneling microscopy experiments, we show that an intermediate coverage of CO on the Pt(110) surface gives rise to a new rough equilibrium structure with more than 50% step atoms. CO is shown to bind...... so strongly to low-coordinated Pt atoms that it can break Pt-Pt bonds and spontaneously form steps on the surface. It is argued that adsorption-induced step formation may be a general effect, in particular at high gas pressures and temperatures....

  7. Step sites in syngas catalysis

    DEFF Research Database (Denmark)

    Rostrup-Nielsen, J.; Nørskov, Jens Kehlet

    2006-01-01

    Step sites play an important role in many catalytic reactions. This paper reviews recent results on metal catalysts for syngas reactions with emphasis on steam reforming. Modern characterization techniques (STEM, HREM...) and theoretical calculations (DFT) has allowed a more quantitative explanat......Step sites play an important role in many catalytic reactions. This paper reviews recent results on metal catalysts for syngas reactions with emphasis on steam reforming. Modern characterization techniques (STEM, HREM...) and theoretical calculations (DFT) has allowed a more quantitative...... explanation of the impact of step sites on catalyst activity and side reactions such as carbon formation. This leads to a discussion of principles for catalyst promotion....

  8. One Step Hydrogen Generation Through Sorption Enhanced Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Mays, Jeff [Gas Technology Inst., Des Plaines, IL (United States)

    2017-08-03

    One-step hydrogen generation, using Sorption Enhanced Reforming (SER) technology, is an innovative means of providing critical energy and environmental improvements to US manufacturing processes. The Gas Technology Institute (GTI) is developing a Compact Hydrogen Generator (CHG) process, based on SER technology, which successfully integrates previously independent process steps, achieves superior energy efficiency by lowering reaction temperatures, and provides pathways to doubling energy productivity with less environmental pollution. GTI’s prior CHG process development efforts have culminated in an operational pilot plant. During the initial pilot testing, GTI identified two operating risks- 1) catalyst coating with calcium aluminate compounds, 2) limited solids handling of the sorbent. Under this contract GTI evaluated alternative materials (one catalyst and two sorbents) to mitigate both risks. The alternate catalyst met performance targets and did not experience coating with calcium aluminate compounds of any kind. The alternate sorbent materials demonstrated viable operation, with one material enabling a three-fold increase in sorbent flow. The testing also demonstrated operation at 90% of its rated capacity. Lastly, a carbon dioxide co-production study was performed to assess the advantage of the solid phase separation of carbon dioxide- inherent in the CHG process. Approximately 70% lower capital cost is achievable compared to SMR-based hydrogen production with CO2 capture, as well as improved operating costs.

  9. The primary steps of photosynthesis

    International Nuclear Information System (INIS)

    Fleming, G.R.; Van Grondelle, R.

    1996-01-01

    The two important initial steps of photosynthesis-electron transfer and energy transfer occur with great speed and efficiency. New techniques in laser optics and genetic engineering age helping us to understand why. (author). 24 refs. 8 figs

  10. 7 Steps to Aging Well

    Science.gov (United States)

    ... Issue Past Issues Special Section 7 Steps to Aging Well Past Issues / Winter 2007 Table of Contents ... Exercise: A Guide from the National Institute on Aging is a publication from NIA that has strength, ...

  11. Step-by-step manual for planning and performing bifurcation PCI: a resource-tailored approach.

    Science.gov (United States)

    Milasinovic, Dejan; Wijns, William; Ntsekhe, Mpiko; Hellig, Farrel; Mohamed, Awad; Stankovic, Goran

    2018-02-02

    As bifurcation PCI can often be resource-demanding due to the use of multiple guidewires, balloons and stents, different technical options are sometimes being explored, in different local settings, to meet the need of optimally treating a patient with a bifurcation lesion, while being confronted with limited material resources. Therefore, it seems important to keep a proper balance between what is recognised as the contemporary state of the art, and what is known to be potentially harmful and to be discouraged. Ultimately, the resource-tailored approach to bifurcation PCI may be characterised by the notion of minimum technical requirements for each step of a successful procedure. Hence, this paper describes the logical sequence of steps when performing bifurcation PCI with provisional SB stenting, starting with basic anatomy assessment and ending with the optimisation of MB stenting and the evaluation of the potential need to stent the SB, suggesting, for each step, the minimum technical requirement for a successful intervention.

  12. A sandpile model of grain blocking and consequences for sediment dynamics in step-pool streams

    Science.gov (United States)

    Molnar, P.

    2012-04-01

    Coarse grains (cobbles to boulders) are set in motion in steep mountain streams by floods with sufficient energy to erode the particles locally and transport them downstream. During transport, grains are often blocked and form width-spannings structures called steps, separated by pools. The step-pool system is a transient, self-organizing and self-sustaining structure. The temporary storage of sediment in steps and the release of that sediment in avalanche-like pulses when steps collapse, leads to a complex nonlinear threshold-driven dynamics in sediment transport which has been observed in laboratory experiments (e.g., Zimmermann et al., 2010) and in the field (e.g., Turowski et al., 2011). The basic question in this paper is if the emergent statistical properties of sediment transport in step-pool systems may be linked to the transient state of the bed, i.e. sediment storage and morphology, and to the dynamics in sediment input. The hypothesis is that this state, in which sediment transporting events due to the collapse and rebuilding of steps of all sizes occur, is analogous to a critical state in self-organized open dissipative dynamical systems (Bak et al., 1988). To exlore the process of self-organization, a cellular automaton sandpile model is used to simulate the processes of grain blocking and hydraulically-driven step collapse in a 1-d channel. Particles are injected at the top of the channel and are allowed to travel downstream based on various local threshold rules, with the travel distance drawn from a chosen probability distribution. In sandpile modelling this is a simple 1-d limited non-local model, however it has been shown to have nontrivial dynamical behaviour (Kadanoff et al., 1989), and it captures the essence of stochastic sediment transport in step-pool systems. The numerical simulations are used to illustrate the differences between input and output sediment transport rates, mainly focussing on the magnification of intermittency and

  13. Preparation for Compensatory Forward Stepping in Parkinson’s Disease

    Science.gov (United States)

    King, Laurie A.; St George, Rebecca J.; Carlson-Kuhta, Patricia; Nutt, John G.; Horak, Fay B.

    2010-01-01

    Objective To characterize preparation for compensatory stepping in people with Parkinson’s disease (PD) compared with healthy control subjects, and to determine whether levodopa medication improves preparation or the execution phases of the step. Design Observational study. Setting Outpatient neuroscience laboratory. Participants Nineteen participants with idiopathic PD tested both in the on and off levodopa states and 17 healthy subjects. Intervention Moveable platform with posterior translations of 24cm at 56cm/s. Main Outcome Measures Compensatory steps forward, in response to a backward surface translation (24cm amplitude at 56cm/s), were categorized according to the presence of an anticipatory postural adjustment (APA) before stepping: no APA, single APA, or multiple APAs. The following step parameters were calculated: step latency, step length, center of mass (CoM) average velocity, and CoM displacement at the step initiation. Results Lateral APAs were evident in 57% and 42% of trials for people with PD in the off and on medication states, respectively, compared with only 10% of trials for control subjects. Compared with subjects with PD who did not have APAs, those subjects with PD who did make an APA prior to stepping had significantly later (mean ± SEM, 356 ± 16ms vs 305 ± 8ms) and shorter (mean ± SEM, 251 ± 27mm vs 300 ± 16mm) steps, their CoM was significantly farther forward (185 ± 7mm vs 171 ± 5mm) at foot-off, and they took significantly more steps to regain equilibrium. Levodopa did not affect the preparation or execution phase of compensatory stepping. Poor axial scores and reports of freezing in the United Parkinson’s Disease Rating Scale were associated with use of 1 or more APAs before compensatory stepping. Conclusions Lateral postural preparation prior to compensatory stepping in subjects with PD was associated with inefficient balance recovery from external perturbations. PMID:20801249

  14. Microsoft® Office Access™ 2007 Step by Step

    CERN Document Server

    Lambert, Steve; Lambert, Joan

    2009-01-01

    Experience learning made easy-and quickly teach yourself how to build database solutions with Access 2007. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them! Build databases from scratch or from templatesExchange data with other databases and Office documentsCreate forms to simplify data entryUse filters and queries to find and analyze informationDesign rich reports that help make your data meaningfulHelp prevent data corruption and unauthorized access Your all-in-one learning experience includes: Files for building skills and practic

  15. Microsoft Windows Sharepoint Services 3.0 Step by Step

    CERN Document Server

    Londer, Olga; Bleeker, Todd; Coventry, Penelope

    2007-01-01

    Experience learning made easy-and quickly teach yourself how to use Windows SharePoint Services to enable effective team collaboration. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them! Build your own SharePoint site with easy-to-use templatesCreate lists and libraries to store informationAdd discussion boards, wikis, and blogsSet up Document and Meeting Workspaces for easy collaborationShare calendars, contacts, and data from Microsoft Office programsCustomize your pages with Web Parts Your all-in-one learning experience includes: Fi

  16. Linear, Step by Step Managerial Performance, versus Exponential Performance

    Directory of Open Access Journals (Sweden)

    George MOLDOVEANU

    2011-04-01

    Full Text Available The paper proposes the transition from the potential management concept, which its authors approached by determining its dimension (Roşca, Moldoveanu, 2009b, to the linear, step by step performance concept, as an objective result of management process. In this way, we “answer” the theorists and practitioners, who support exponential management performance. The authors, as detractors of the exponential performance, are influenced by the current crisis (Roşca, Moldoveanu, 2009a, by the lack of organizational excellence in many companies, particularly in Romanian ones and also reaching “the finality” in the evolved companies, developed into an uncontrollable speed.

  17. Microsoft Office SharePoint Designer 2007 Step by Step

    CERN Document Server

    Coventry, Penelope

    2008-01-01

    The smart way to learn Office SharePoint Designer 2007-one step at a time! Work at your own pace through the easy numbered steps, practice files on CD, helpful hints, and troubleshooting tips to master the fundamentals of building customized SharePoint sites and applications. You'll learn how to work with Windows® SharePoint Services 3.0 and Office SharePoint Server 2007 to create Web pages complete with Cascading Style Sheets, Lists, Libraries, and customized Web parts. Then, make your site really work for you by adding data sources, including databases, XML data and Web services, and RSS fe

  18. A step-by-step methodology for enterprise interoperability projects

    Science.gov (United States)

    Chalmeta, Ricardo; Pazos, Verónica

    2015-05-01

    Enterprise interoperability is one of the key factors for enhancing enterprise competitiveness. Achieving enterprise interoperability is an extremely complex process which involves different technological, human and organisational elements. In this paper we present a framework to help enterprise interoperability. The framework has been developed taking into account the three domains of interoperability: Enterprise Modelling, Architecture and Platform and Ontologies. The main novelty of the framework in comparison to existing ones is that it includes a step-by-step methodology that explains how to carry out an enterprise interoperability project taking into account different interoperability views, like business, process, human resources, technology, knowledge and semantics.

  19. One step beyond: Different step-to-step transitions exist during continuous contact brachiation in siamangs

    Directory of Open Access Journals (Sweden)

    Fana Michilsens

    2012-02-01

    In brachiation, two main gaits are distinguished, ricochetal brachiation and continuous contact brachiation. During ricochetal brachiation, a flight phase exists and the body centre of mass (bCOM describes a parabolic trajectory. For continuous contact brachiation, where at least one hand is always in contact with the substrate, we showed in an earlier paper that four step-to-step transition types occur. We referred to these as a ‘point’, a ‘loop’, a ‘backward pendulum’ and a ‘parabolic’ transition. Only the first two transition types have previously been mentioned in the existing literature on gibbon brachiation. In the current study, we used three-dimensional video and force analysis to describe and characterize these four step-to-step transition types. Results show that, although individual preference occurs, the brachiation strides characterized by each transition type are mainly associated with speed. Yet, these four transitions seem to form a continuum rather than four distinct types. Energy recovery and collision fraction are used as estimators of mechanical efficiency of brachiation and, remarkably, these parameters do not differ between strides with different transition types. All strides show high energy recoveries (mean  = 70±11.4% and low collision fractions (mean  = 0.2±0.13, regardless of the step-to-step transition type used. We conclude that siamangs have efficient means of modifying locomotor speed during continuous contact brachiation by choosing particular step-to-step transition types, which all minimize collision fraction and enhance energy recovery.

  20. Stability study in one step steam generators

    International Nuclear Information System (INIS)

    Abbate, P.

    1990-01-01

    The TWO program is presented developed for the behaviour limit calculation stable in one step steam generators for the case of Density Waves phenomenom. The program is based on a nodal model which, using Laplace transformation equations, allows to study the system's transfer functions and foresee the beginning of the unstable behaviour. This program has been satisfactorily validated against channels data uniformly heated in the range from 4.0 to 6.0 Mpa. Results on the CAREM reactor's steam generator analysis are presented. (Author) [es

  1. High accuracy step gauge interferometer

    Science.gov (United States)

    Byman, V.; Jaakkola, T.; Palosuo, I.; Lassila, A.

    2018-05-01

    Step gauges are convenient transfer standards for the calibration of coordinate measuring machines. A novel interferometer for step gauge calibrations implemented at VTT MIKES is described. The four-pass interferometer follows Abbe’s principle and measures the position of the inductive probe attached to a measuring head. The measuring head of the instrument is connected to a balanced boom above the carriage by a piezo translation stage. A key part of the measuring head is an invar structure on which the inductive probe and the corner cubes of the measuring arm of the interferometer are attached. The invar structure can be elevated so that the probe is raised without breaking the laser beam. During probing, the bending of the probe and the interferometer readings are recorded and the measurement face position is extrapolated to zero force. The measurement process is fully automated and the face positions of the steps can be measured up to a length of 2 m. Ambient conditions are measured continuously and the refractive index of air is compensated for. Before measurements the step gauge is aligned with an integrated 2D coordinate measuring system. The expanded uncertainty of step gauge calibration is U=\\sqrt{{{(64 nm)}2}+{{(88× {{10}-9}L)}2}} .

  2. Digital project management the complete step-by-step guide to a successful launch

    CERN Document Server

    Olson, Taylor

    2016-01-01

    The digital world is growing and changing at a rate that can seem overwhelming to those project managers who have to keep up with it to build customer-facing solutions and applications. It's rare for project managers working in this field to be provided with much direction or a process by which to carry out a project, and there has been next to nothing available specific to these types of projects in the literary marketplace. Digital Project Management: The Complete Step-by-Step Guide to a Successful Launch was developed to fill this gap by providing the knowledge, best practices and proven steps to consistently managing these types of project successfully from end-to-end now, and in the future with just minor adjustments to adapt to changes in technology.

  3. From raw material to dish: pasta quality step by step.

    Science.gov (United States)

    Sicignano, Angelo; Di Monaco, Rossella; Masi, Paolo; Cavella, Silvana

    2015-10-01

    Pasta is a traditional Italian cereal-based food that is popular worldwide because of its convenience, versatility, sensory and nutritional value. The aim of this review is to present a step-by-step guide to facilitate the understanding of the most important events that can affect pasta characteristics, directing the reader to the appropriate production steps. Owing to its unique flavor, color, composition and rheological properties, durum wheat semolina is the best raw material for pasta production. Although pasta is traditionally made from only two ingredients, sensory quality and chemical/physical characteristics of the final product may vary greatly. Starting from the same ingredients, there are a lot of different events in each step of pasta production that can result in the development of varieties of pasta with different characteristics. In particular, numerous studies have demonstrated the importance of temperature and humidity conditions of the pasta drying operation as well as the significance of the choice of raw material and operating conditions on pasta quality. © 2015 Society of Chemical Industry.

  4. Step by step parallel programming method for molecular dynamics code

    International Nuclear Information System (INIS)

    Orii, Shigeo; Ohta, Toshio

    1996-07-01

    Parallel programming for a numerical simulation program of molecular dynamics is carried out with a step-by-step programming technique using the two phase method. As a result, within the range of a certain computing parameters, it is found to obtain parallel performance by using the level of parallel programming which decomposes the calculation according to indices of do-loops into each processor on the vector parallel computer VPP500 and the scalar parallel computer Paragon. It is also found that VPP500 shows parallel performance in wider range computing parameters. The reason is that the time cost of the program parts, which can not be reduced by the do-loop level of the parallel programming, can be reduced to the negligible level by the vectorization. After that, the time consuming parts of the program are concentrated on less parts that can be accelerated by the do-loop level of the parallel programming. This report shows the step-by-step parallel programming method and the parallel performance of the molecular dynamics code on VPP500 and Paragon. (author)

  5. Predicting Translation Initiation Rates for Designing Synthetic Biology

    International Nuclear Information System (INIS)

    Reeve, Benjamin; Hargest, Thomas; Gilbert, Charlie; Ellis, Tom

    2014-01-01

    In synthetic biology, precise control over protein expression is required in order to construct functional biological systems. A core principle of the synthetic biology approach is a model-guided design and based on the biological understanding of the process, models of prokaryotic protein production have been described. Translation initiation rate is a rate-limiting step in protein production from mRNA and is dependent on the sequence of the 5′-untranslated region and the start of the coding sequence. Translation rate calculators are programs that estimate protein translation rates based on the sequence of these regions of an mRNA, and as protein expression is proportional to the rate of translation initiation, such calculators have been shown to give good approximations of protein expression levels. In this review, three currently available translation rate calculators developed for synthetic biology are considered, with limitations and possible future progress discussed.

  6. Time step MOTA thermostat simulation

    International Nuclear Information System (INIS)

    Guthrie, G.L.

    1978-09-01

    The report details the logic, program layout, and operating procedures for the time-step MOTA (Materials Open Test Assembly) thermostat simulation program known as GYRD. It will enable prospective users to understand the operation of the program, run it, and interpret the results. The time-step simulation analysis was the approach chosen to determine the maximum value gain that could be used to minimize steady temperature offset without risking undamped thermal oscillations. The advantage of the GYRD program is that it directly shows hunting, ringing phenomenon, and similar events. Programs BITT and CYLB are faster, but do not directly show ringing time

  7. A mechanism for leader stepping

    Science.gov (United States)

    Ebert, U.; Carlson, B. E.; Koehn, C.

    2013-12-01

    The stepping of negative leaders is well observed, but not well understood. A major problem consists of the fact that the streamer corona is typically invisible within a thunderstorm, but determines the evolution of a leader. Motivated by recent observations of streamer and leader formation in the laboratory by T.M.P. Briels, S. Nijdam, P. Kochkin, A.P.J. van Deursen et al., by recent simulations of these processes by J. Teunissen, A. Sun et al., and by our theoretical understanding of the process, we suggest how laboratory phenomena can be extrapolated to lightning leaders to explain the stepping mechanism.

  8. Dynamic balance and stepping versus tai chi training to improve balance and stepping in at-risk older adults.

    Science.gov (United States)

    Nnodim, Joseph O; Strasburg, Debra; Nabozny, Martina; Nyquist, Linda; Galecki, Andrzej; Chen, Shu; Alexander, Neil B

    2006-12-01

    To compare the effect of two 10-week balance training programs, Combined Balance and Step Training (CBST) versus tai chi (TC), on balance and stepping measures. Prospective intervention trial. Local senior centers and congregate housing facilities. Aged 65 and older with at least mild impairment in the ability to perform unipedal stance and tandem walk. Participants were allocated to TC (n = 107, mean age 78) or CBST, an intervention focused on improving dynamic balance and stepping (n = 106, mean age 78). At baseline and 10 weeks, participants were tested in their static balance (Unipedal Stance and Tandem Stance (TS)), stepping (Maximum Step Length, Rapid Step Test), and Timed Up and Go (TUG). Performance improved more with CBST than TC, ranging from 5% to 10% for the stepping tests (Maximum Step Length and Rapid Step Test) and 9% for TUG. The improvement in TUG represented an improvement of more than 1 second. Greater improvements were also seen in static balance ability (in TS) with CBST than TC. Of the two training programs, in which variants of each program have been proven to reduce falls, CBST results in modest improvements in balance, stepping, and functional mobility versus TC over a 10-week period. Future research should include a prospective comparison of fall rates in response to these two balance training programs.

  9. Angular momentum in multi-step photoionization

    International Nuclear Information System (INIS)

    Yoshida, Tadashi; Adachi, Hajime; Kuwako, Akira; Nittoh, Koichi; Araki, Yoshio; Watanabe, Takashi; Yoguchi, Itaru.

    1995-01-01

    The effect of the angular momenta on the multi-step laser-ionization efficiency was investigated numerically for cases with and without the hyperfine interactions. For either cases the ionization efficiency proved to depend appreciably on the values of J in the excitation ladder. In this respect, we elaborated a simple and efficient method of determining J, which was based on the laser polarization dependence of the excitation rate. Application of this method to a couple of real excitation ladders proved its usefulness and reliability. (author)

  10. Driver training in steps (DTS).

    NARCIS (Netherlands)

    2010-01-01

    For some years now, it has been possible in the Netherlands to follow a Driver Training in Steps (DTS) as well as the regular driver training. The DTS is a structured training method with clear training objectives which are categorized in four modules. Although the DTS is considerably better than

  11. Stepping out: dare to step forward, step back, or just stand still and breathe.

    Science.gov (United States)

    Waisman, Mary Sue

    2012-01-01

    It is important to step out and make a difference. We have one of the most unique and diverse professions that allows for diversity in thought and practice, permitting each of us to grow in our unique niches and make significant contributions. I was frightened to 'step out' to go to culinary school at the age of 46, but it changed forever the way I look at my profession and I have since experienced the most enjoyable and innovative career. There are also times when it is important to 'step back' to relish the roots of our profession; to help bring food back into nutrition; to translate all of our wonderful science into a language of food that Canadians understand. We all need to take time to 'just stand still and breathe': to celebrate our accomplishments, reflect on our actions, ensure we are heading toward our vision, keep the profession vibrant and relevant, and cherish one another.

  12. 2-Step IMAT and 2-Step IMRT in three dimensions

    International Nuclear Information System (INIS)

    Bratengeier, Klaus

    2005-01-01

    In two dimensions, 2-Step Intensity Modulated Arc Therapy (2-Step IMAT) and 2-Step Intensity Modulated Radiation Therapy (IMRT) were shown to be powerful methods for the optimization of plans with organs at risk (OAR) (partially) surrounded by a target volume (PTV). In three dimensions, some additional boundary conditions have to be considered to establish 2-Step IMAT as an optimization method. A further aim was to create rules for ad hoc adaptations of an IMRT plan to a daily changing PTV-OAR constellation. As a test model, a cylindrically symmetric PTV-OAR combination was used. The centrally placed OAR can adapt arbitrary diameters with different gap widths toward the PTV. Along the rotation axis the OAR diameter can vary, the OAR can even vanish at some axis positions, leaving a circular PTV. The width and weight of the second segment were the free parameters to optimize. The objective function f to minimize was the root of the integral of the squared difference of the dose in the target volume and a reference dose. For the problem, two local minima exist. Therefore, as a secondary criteria, the magnitude of hot and cold spots were taken into account. As a result, the solution with a larger segment width was recommended. From plane to plane for varying radii of PTV and OAR and for different gaps between them, different sets of weights and widths were optimal. Because only one weight for one segment shall be used for all planes (respectively leaf pairs), a strategy for complex three-dimensional (3-D) cases was established to choose a global weight. In a second step, a suitable segment width was chosen, minimizing f for this global weight. The concept was demonstrated in a planning study for a cylindrically symmetric example with a large range of different radii of an OAR along the patient axis. The method is discussed for some classes of tumor/organ at risk combinations. Noncylindrically symmetric cases were treated exemplarily. The product of width and weight of

  13. Limit lines for risk

    International Nuclear Information System (INIS)

    Cox, D.C.; Baybutt, P.

    1982-01-01

    Approaches to the regulation of risk from technological systems, such as nuclear power plants or chemical process plants, in which potential accidents may result in a broad range of adverse consequences must take into account several different aspects of risk. These include overall or average risk, accidents posing high relative risks, the rate at which accident probability decreases with increasing accident consequences, and the impact of high frequency, low consequence accidents. A hypothetical complementary cumulative distribution function (CCDF), with appropriately chosen parametric form, meets all these requirements. The Farmer limit line, by contrast, places limits on the risks due to individual accident sequences, and cannot adequately account for overall risk. This reduces its usefulness as a regulatory tool. In practice, the CCDF is used in the Canadian nuclear licensing process, while the Farmer limit line approach, supplemented by separate qualitative limits on overall risk, is employed in the United Kingdom

  14. Energetics of highly kinked step edges

    NARCIS (Netherlands)

    Zandvliet, Henricus J.W.

    2010-01-01

    We have determined the step edge free energy, the step edge stiffness and dimensionless inverse step edge stiffness of the highly kinked < 010> oriented step on a (001) surface of a simple square lattice within the framework of a solid-on-solid model. We have found an exact expression for the step

  15. The added value of a mobile application of Community Case Management on referral, re-consultation and hospitalization rates of children aged under 5 years in two districts in Northern Malawi: study protocol for a pragmatic, stepped-wedge cluster-randomized controlled trial.

    Science.gov (United States)

    Hardy, Victoria; O'Connor, Yvonne; Heavin, Ciara; Mastellos, Nikolaos; Tran, Tammy; O'Donoghue, John; Fitzpatrick, Annette L; Ide, Nicole; Wu, Tsung-Shu Joseph; Chirambo, Griphin Baxter; Muula, Adamson S; Nyirenda, Moffat; Carlsson, Sven; Andersson, Bo; Thompson, Matthew

    2017-10-11

    There is evidence to suggest that frontline community health workers in Malawi are under-referring children to higher-level facilities. Integrating a digitized version of paper-based methods of Community Case Management (CCM) could strengthen delivery, increasing urgent referral rates and preventing unnecessary re-consultations and hospital admissions. This trial aims to evaluate the added value of the Supporting LIFE electronic Community Case Management Application (SL eCCM App) compared to paper-based CCM on urgent referral, re-consultation and hospitalization rates, in two districts in Northern Malawi. This is a pragmatic, stepped-wedge cluster-randomized trial assessing the added value of the SL eCCM App on urgent referral, re-consultation and hospitalization rates of children aged 2 months and older to up to 5 years, within 7 days of the index visit. One hundred and two health surveillance assistants (HSAs) were stratified into six clusters based on geographical location, and clusters randomized to the timing of crossover to the intervention using simple, computer-generated randomization. Training workshops were conducted prior to the control (paper-CCM) and intervention (paper-CCM + SL eCCM App) in assigned clusters. Neither participants nor study personnel were blinded to allocation. Outcome measures were determined by abstraction of clinical data from patient records 2 weeks after recruitment. A nested qualitative study explored perceptions of adherence to urgent referral recommendations and a cost evaluation determined the financial and time-related costs to caregivers of subsequent health care utilization. The trial was conducted between July 2016 and February 2017. This is the first large-scale trial evaluating the value of adding a mobile application of CCM to the assessment of children aged under 5 years. The trial will generate evidence on the potential use of mobile health for CCM in Malawi, and more widely in other low- and middle

  16. Step 2: Know Your Diabetes ABCs

    Science.gov (United States)

    ... please turn JavaScript on. Feature: Type 2 Diabetes Step 2: Know Your Diabetes ABCs Past Issues / Fall ... 2 Diabetes" Articles Diabetes Is Serious But Manageable / Step 1: Learn About Diabetes / Step 2: Know Your ...

  17. From quality control to quality systems in x-ray radiology. Step by step approach

    International Nuclear Information System (INIS)

    Gendrutis Morkunas; Julius Ziliukas

    2007-01-01

    Complete test of publication follows. Quality systems in x-ray radiology as in any area of medical exposure is an important tool of optimization of radiation protection. Creation of these systems is related with a number of problems: limited resources, lack of knowledge and experience, negative attitude of hospitals staff and administration, lack of advice from outside. Problems related with transitionary period might be softened by the step by step approach. The following steps might be indicated: providing information on quality systems to hospital staff and administration, simple quality control procedures done by outside experts in hospitals, preparation of quality related procedures by hospital staff, practical implementation of quality control procedures done by hospital staff, preparation of quality manual by hospital staff, its integration into common quality system of hospital (if it is available) and constant development, measurements of performance indicators (e.g., patients' doses) and introduction of corrective measures if necessary, dissemination of experience by expert organizations and more advanced hospitals. These steps are to be discussed in the presentations based on Lithuanian experience since 1998.

  18. Step training improves reaction time, gait and balance and reduces falls in older people: a systematic review and meta-analysis.

    Science.gov (United States)

    Okubo, Yoshiro; Schoene, Daniel; Lord, Stephen R

    2017-04-01

    To examine the effects of stepping interventions on fall risk factors and fall incidence in older people. Electronic databases (PubMed, EMBASE, CINAHL, Cochrane, CENTRAL) and reference lists of included articles from inception to March 2015. Randomised (RCT) or clinical controlled trials (CCT) of volitional and reactive stepping interventions that included older (minimum age 60) people providing data on falls or fall risk factors. Meta-analyses of seven RCTs (n=660) showed that the stepping interventions significantly reduced the rate of falls (rate ratio=0.48, 95% CI 0.36 to 0.65, prisk ratio=0.51, 95% CI 0.38 to 0.68, pfalls and proportion of fallers. A meta-analysis of two RCTs (n=62) showed that stepping interventions significantly reduced laboratory-induced falls, and meta-analysis findings of up to five RCTs and CCTs (n=36-416) revealed that stepping interventions significantly improved simple and choice stepping reaction time, single leg stance, timed up and go performance (pfalls among older adults by approximately 50%. This clinically significant reduction may be due to improvements in reaction time, gait, balance and balance recovery but not in strength. Further high-quality studies aimed at maximising the effectiveness and feasibility of stepping interventions are required. CRD42015017357. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  19. The STEP database through the end-users eyes--USABILITY STUDY.

    Science.gov (United States)

    Salunke, Smita; Tuleu, Catherine

    2015-08-15

    The user-designed database of Safety and Toxicity of Excipients for Paediatrics ("STEP") is created to address the shared need of drug development community to access the relevant information of excipients effortlessly. Usability testing was performed to validate if the database satisfies the need of the end-users. Evaluation framework was developed to assess the usability. The participants performed scenario based tasks and provided feedback and post-session usability ratings. Failure Mode Effect Analysis (FMEA) was performed to prioritize the problems and improvements to the STEP database design and functionalities. The study revealed several design vulnerabilities. Tasks such as limiting the results, running complex queries, location of data and registering to access the database were challenging. The three critical attributes identified to have impact on the usability of the STEP database included (1) content and presentation (2) the navigation and search features (3) potential end-users. Evaluation framework proved to be an effective method for evaluating database effectiveness and user satisfaction. This study provides strong initial support for the usability of the STEP database. Recommendations would be incorporated into the refinement of the database to improve its usability and increase user participation towards the advancement of the database. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Step-By-Step: Life Cycle Radioactive Waste Management

    International Nuclear Information System (INIS)

    2014-01-01

    Radioactive waste is an unavoidable by-product when nuclear technologies are used for electricity production and for beneficial practices in medicine, agriculture, research and industry. When the radioactivity of the waste is above a certain threshold, the waste requires special disposal methods. Through extensive research, standards and approaches have been developed for safely and securely preparing for and managing radioactive waste disposal. In the course of its journey from the point of generation to disposal, radioactive waste undergoes a number of predisposal management treatment steps to transform it into a safe, stable and manageable form suitable for transport, storage and disposal

  1. Blogging business step-by-step startup guide

    CERN Document Server

    magazine, Entrepreneur

    2014-01-01

    This kit includes: Essential industry and business-specific startup steps with worksheets, calculators, checklists and more. Entrepreneur Editors' Start Your Own Business, a guide to starting any business and surviving the first three years. Downloadable, customizable business letters, sales letters, and other sample documents. Entrepreneur's Small Business Legal Toolkit. Blogs are still one of the internet's fastest-growing phenomena–and one of the best and easiest ways to make money online. Packed with the latest blog tools, tricks, and up-and-coming trends, this fully revised edition teache

  2. Neural-net predictor for beta limit disruptions in JT-60U

    International Nuclear Information System (INIS)

    Yoshino, R.

    2005-01-01

    Prediction of major disruptions occurring at the β -limit for tokamak plasmas with a normal magnetic shear in JT-60U was conducted using neural networks. Since no clear precursors are generally observed a few tens of milliseconds before the β -limit disruption, a sub-neural network is trained to output the value of the β N limit every 2 ms. The target β N limit is artificially set by the operator in the first step to train a network with non-disruptive shots as well as disruptive shots, and then in the second step the target limit is modified using the β N limit output from the trained network. The adjusted target greatly improves the consistency between the input data and the output. This training, the 'self-teaching method', has greatly reduced the false alarm rate triggered for non-disruptive shots. To improve the prediction performance further, the difference between the output β N limit and the measured β N , and 11 parameters, are inputted to the main neural network to calculate the 'stability level'. The occurrence of a major disruption is predicted when the stability level decreases to the 'alarm level'. Major disruptions at the β -limit have been predicted by the main network with a prediction success rate of 80% at 10 ms prior to the disruption while the false alarm rate is lower than 4% for non-disruptive shots. This 80% value is much higher than that obtained for a network trained with a fixed target β N limit set to be the maximum β N observed at the start of a major disruption, lower than 10%. A prediction success rate of 90% with a false alarm rate of 12% at 10 ms prior to the disruption has also been obtained. This 12% value is about half of that obtained for a network trained with a fixed target β N limit

  3. Role of steps in N-2 activation on Ru(0001)

    DEFF Research Database (Denmark)

    Dahl, Søren; Logadottir, Ashildur; Egeberg, Rasmus

    1999-01-01

    Using adsorption experiments and density functional calculations we show that N-2 dissociation on the Ru(0001) surface is totally dominated by steps. The measured adsorption rate at the steps is at least 9 orders of magnitude higher than on the terraces at 500 K, and the corresponding calculated ...... difference in activation energy is 1.5 eV. The low barrier at the step is shown to be due to a combination of electronic and geometrical effects. The consequences for Ru as a catalyst for ammonia synthesis are discussed....

  4. Robotic retroperitoneal partial nephrectomy: a step-by-step guide.

    Science.gov (United States)

    Ghani, Khurshid R; Porter, James; Menon, Mani; Rogers, Craig

    2014-08-01

    To describe a step-by-step guide for successful implementation of the retroperitoneal approach to robotic partial nephrectomy (RPN) PATIENTS AND METHODS: The patient is placed in the flank position and the table fully flexed to increase the space between the 12th rib and iliac crest. Access to the retroperitoneal space is obtained using a balloon-dilating device. Ports include a 12-mm camera port, two 8-mm robotic ports and a 12-mm assistant port placed in the anterior axillary line cephalad to the anterior superior iliac spine, and 7-8 cm caudal to the ipsilateral robotic port. Positioning and port placement strategies for successful technique include: (i) Docking robot directly over the patient's head parallel to the spine; (ii) incision for camera port ≈1.9 cm (1 fingerbreadth) above the iliac crest, lateral to the triangle of Petit; (iii) Seldinger technique insertion of kidney-shaped balloon dilator into retroperitoneal space; (iv) Maximising distance between all ports; (v) Ensuring camera arm is placed in the outer part of the 'sweet spot'. The retroperitoneal approach to RPN permits direct access to the renal hilum, no need for bowel mobilisation and excellent visualisation of posteriorly located tumours. © 2014 The Authors. BJU International © 2014 BJU International.

  5. Sodium tetraphenylborate solubility and dissolution rates

    International Nuclear Information System (INIS)

    Barnes, M.J.; Peterson, R.A.; Swingle, R.F.; Reeves, C.T.

    1995-01-01

    The rate of solid sodium tetraphenylborate (NaTPB) dissolution in In-Tank Precipitation salt solutions has been experimentally determined. The data indicates that the dissolution rate of solid NaTPB is a minor contributor the lag time experienced in the 1983 Salt Decontamination Demonstration Test and should not be considered as the rate determining step. Current analytical models for predicting the time to reach the composite lower flammability limit assume that the lag time is not more than 6 hours, and the data supports this assumption (i.e., dissolution by itself requires much less than 6 hours). The data suggests that another step--such as mass transport, the reaction of a benzene precursor or the mixing behavior--is the rate determining factor for benzene release to the vapor space in Tank 48H. In addition, preliminary results from this program show that the degree of agitation employed is not a significant parameter in determining the rate of NaTPB dissolution. As a result of this study, an improved equation for predicting equilibrium tetraphenylborate solubility with respect to temperature and sodium ion concentration has been determined

  6. Experimental investigation of stepped solar still with continuous water circulation

    International Nuclear Information System (INIS)

    El-Agouz, S.A.

    2014-01-01

    Highlights: • Comparison between modified stepped and conventional solar still was carried out. • Effect of storage tank and cotton absorber on productivity was investigated. • Efficiency for modified stepped still is higher than conventional still by 20%. • The day and night efficiency increases by 5% and 3.5% for salt and sea water. - Abstract: This paper presents a modification of stepped solar still with continuous water circulation using a storage tank for sea and salt water. Total dissolved solids (TDS) of seawater and salt water before desalination is 57,100 and 2370 mg/l. A comparison study between modified stepped and conventional solar still was carried out to evaluate the developed desalination system performance under the same climate conditions. The effect of installing a storage tank and cotton black absorber for modified stepped solar still on the distillate productivity was investigated. The results indicate that, the productivity of the modified stepped still is higher than that for conventional still approximately by 43% and 48% for sea and salt water with black absorber respectively, while 53% and 47% of sea and salt water, respectively with cotton absorber. Also, the daily efficiency for modified stepped still is higher than that for conventional still approximately by 20%. The maximum efficiency of modified stepped still is occurring at a feed water flow rate of 1 LPM for sea water and 3 LPM for salt water. Total dissolved solids (TDS) of seawater and salt water after desalination is 41, and 27 mg/l

  7. An approach to next step device optimisation

    International Nuclear Information System (INIS)

    Salpietro, E.

    2000-01-01

    The requirements for ITER EDA were to achieve ignition with a good safety margin, and controlled long inductive burn. These requirements lead to a big device, which requested a too ambitious step to be undertaken by the world fusion community. More realistic objectives for a next step device shall be to demonstrate the net production of energy with a high energy gain factor (Q) and a high boot strap current fraction (>60%) which is required for a Fusion Power Plant (FPP). The Next Step Device (NSD) shall also allow operation flexibility in order to explore a large range of plasma parameters to find out the optimum concept for the fusion power plant prototype. These requirements could be too demanding for one single device and could probably be better explored in a strongly integrated world programme. The cost of one or more devices is the decisive factor for the choice of the fusion power development programme strategy. The plasma elongation and triangularity have a strong impact in the cost of the device and are limited by the plasma vertical position control issue. The distance between plasma separatrix and the toroidal field conductor does not vary a lot between devices. It is determined by the sum of the distance between first wall-plasma sepratrix and the thickness of the nuclear shield required to protect the toroidal field coil insultation. The thickness of the TF coil is determined by the allowable stresses and superconducting characteristics. The outer radius of the central solenoid is the result of an optimisation to provide the magnetic flux to inductively drive the plasma. Therefore, in order to achieve the objectives for Q and boot-strap current fractions at the minimum cost, the plasma aspect ratio and magnetic field value shall be determined. The paper will present the critical issues for the next device and will make considerations on the optimal way to proceed towards the realisation of the fusion power plant

  8. Next Step Spherical Torus Design Studies

    International Nuclear Information System (INIS)

    Neumeyer, C.; Heitzenroeder, P.; Kessel, C.; Ono, M.; Peng, M.; Schmidt, J.; Woolley, R.; Zatz, I.

    2002-01-01

    Studies are underway to identify and characterize a design point for a Next Step Spherical Torus (NSST) experiment. This would be a ''Proof of Performance'' device which would follow and build upon the successes of the National Spherical Torus Experiment (NSTX) a ''Proof of Principle'' device which has operated at PPPL since 1999. With the Decontamination and Decommissioning (DandD) of the Tokamak Fusion Test Reactor (TFTR) nearly completed, the TFTR test cell and facility will soon be available for a device such as NSST. By utilizing the TFTR test cell, NSST can be constructed for a relatively low cost on a short time scale. In addition, while furthering spherical torus (ST) research, this device could achieve modest fusion power gain for short-pulse lengths, a significant step toward future large burning plasma devices now under discussion in the fusion community. The selected design point is Q=2 at HH=1.4, P subscript ''fusion''=60 MW, 5 second pulse, with R subscript ''0''=1.5 m, A=1.6, I subscript ''p''=10vMA, B subscript ''t''=2.6 T, CS flux=16 weber. Most of the research would be conducted in D-D, with a limited D-T campaign during the last years of the program

  9. Solubility limits on radionuclide dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Kerrisk, J.F.

    1984-12-31

    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.

  10. Steps in Researching the Music in Therapy

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2007-01-01

    The chapter introduces a generic flowchart + step-by-step guide for microanalysis of music (compositions and improvisations) in music therapy.......The chapter introduces a generic flowchart + step-by-step guide for microanalysis of music (compositions and improvisations) in music therapy....

  11. Group sequential designs for stepped-wedge cluster randomised trials.

    Science.gov (United States)

    Grayling, Michael J; Wason, James Ms; Mander, Adrian P

    2017-10-01

    The stepped-wedge cluster randomised trial design has received substantial attention in recent years. Although various extensions to the original design have been proposed, no guidance is available on the design of stepped-wedge cluster randomised trials with interim analyses. In an individually randomised trial setting, group sequential methods can provide notable efficiency gains and ethical benefits. We address this by discussing how established group sequential methodology can be adapted for stepped-wedge designs. Utilising the error spending approach to group sequential trial design, we detail the assumptions required for the determination of stepped-wedge cluster randomised trials with interim analyses. We consider early stopping for efficacy, futility, or efficacy and futility. We describe first how this can be done for any specified linear mixed model for data analysis. We then focus on one particular commonly utilised model and, using a recently completed stepped-wedge cluster randomised trial, compare the performance of several designs with interim analyses to the classical stepped-wedge design. Finally, the performance of a quantile substitution procedure for dealing with the case of unknown variance is explored. We demonstrate that the incorporation of early stopping in stepped-wedge cluster randomised trial designs could reduce the expected sample size under the null and alternative hypotheses by up to 31% and 22%, respectively, with no cost to the trial's type-I and type-II error rates. The use of restricted error maximum likelihood estimation was found to be more important than quantile substitution for controlling the type-I error rate. The addition of interim analyses into stepped-wedge cluster randomised trials could help guard against time-consuming trials conducted on poor performing treatments and also help expedite the implementation of efficacious treatments. In future, trialists should consider incorporating early stopping of some kind into

  12. Thermal fatigue in mixing tees: A step by step simplified procedure

    International Nuclear Information System (INIS)

    Faidy, Claude

    2003-01-01

    Following the CIVAUX 1 incident of a leak on RHR system, EDF has developed a step by step procedure to screen and analyse similar locations: mixing tees with long duration at high ΔT between the 2 fluids. The paper present the procedure, the background of the methodology and few R and D work that support this procedure. The procedure is based on: screening criteria on maximum DT and minimum duration. screening criteria without any duration consideration, only DT and material. a simplified and conservative estimation of a usage factor. a detailed analysis of usage factor and crack growth rate, based on specific data collection of operating transients. Around that procedure EDF launched an R and D program on fatigue curves and fatigue reduction factors for high cycle fatigue. The procedure is compared with field experience and recent R and D fatigue tests. (author)

  13. Step-by-step approach to convective cooling of laser disc amplifiers

    International Nuclear Information System (INIS)

    Bourque, R.F.

    1979-04-01

    A step by step approach is presented to the problem of gas cooling of laser glass amplifiers. The basic equations are given for glass conduction, thermal stress, gas convection, and heat exchanger and blower design. An example calculation is then carried out for helium gas at one atmosphere with the gas flow in the direction orthogonal to the optical path. It is found that pumping powers and temperatures are acceptable for this case. Results are also presented for helium in the slant direction and for nitrogen in both directions. Included also are the effects on pumping power of gas temperature rise, gas pressure, flashtube rep rate, and flow channel width. It is found that, based on temperature rise and pumping power, nitrogen is as viable a coolant as helium

  14. Diffraction model of a step-out transition

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A.W.; Zimmermann, F.

    1996-06-01

    The diffraction model of a cavity, suggested by Lawson, Bane and Sands is generalized to a step out transition. Using this model, the high frequency impedance is calculated explicitly for the case that the transition step is small compared with the beam pipe radius. In the diffraction model for a small step out transition, the total energy is conserved, but, unlike the cavity case, the diffracted waves in the geometric shadow and the pipe region, in general, do not always carry equal energy. In the limit of small step sizes, the impedance derived from the diffraction model agrees with that found by Balakin, Novokhatsky and also Kheifets. This impedance can be used to compute the wake field of a round collimator whose half aperture is much larger than the bunch length, as existing in the SLC final focus.

  15. Required Steps of Managing International Equity Placement Strategic Alliance

    Directory of Open Access Journals (Sweden)

    Harimukti Wandebori

    2011-12-01

    Full Text Available The purpose of the research is to unravel the steps of managing international equity placement strategic alliance (IEPSA. The steps of managing an IEPSA are obtained by conducting theoretical review. The theoretical reviews consist of theory of strategic alliance; definition, classification, and finding definition of an IEPSA, political and analytical considerations and the necessary steps. These steps of managing IEPSA can be classified into analyzing of macro consideration, micro consideration, domestic company’s stakeholder support, cultural understanding, strategic planning, internal support, human resource management, organizational arrangement, management control system, evolved cultural understanding, and evaluating results. In this research, the domestic partners who formed the IEPSAs are limited to State-Owned Enterprises (SOEs. The IEPSA was one of the means of privatization. The research will be beneficial for both foreign and domestic partners who form an IEPSA in the previous SOEs. By knowing the steps of managing the IEPSA both partners will be able to secure a successful implementation of IEPSA. By identifying the steps of managing the IEPSA, the stakeholder will not see IEPSA as threat rather as an opportunity to improve performance, to create synergy, and generate benefits for both partners and stakeholder. By knowing the necessary steps of managing the IEPSA, the stakeholder including society and politician will envisage the IEPSA as a means of effectively improving the SOEs’ performances.The research was espected to provide contributions for the research on strategic alliances. Apparently, there exist no literatures discussing about IEPSA in the domain of strategic alliances.

  16. HVS-based quantization steps for validation of digital cinema extended bitrates

    Science.gov (United States)

    Larabi, M.-C.; Pellegrin, P.; Anciaux, G.; Devaux, F.-O.; Tulet, O.; Macq, B.; Fernandez, C.

    2009-02-01

    In Digital Cinema, the video compression must be as transparent as possible to provide the best image quality to the audience. The goal of compression is to simplify transport, storing, distribution and projection of films. For all those tasks, equipments need to be developed. It is thus mandatory to reduce the complexity of the equipments by imposing limitations in the specifications. In this sense, the DCI has fixed the maximum bitrate for a compressed stream to 250 Mbps independently from the input format (4K/24fps, 2K/48fps or 2K/24fps). The work described in this paper This parameter is discussed in this paper because it is not consistent to double/quadruple the input rate without increasing the output rate. The work presented in this paper is intended to define quantization steps ensuring the visually lossless compression. Two steps are followed first to evaluate the effect of each subband separately and then to fin the scaling ratio. The obtained results show that it is necessary to increase the bitrate limit for cinema material in order to achieve the visually lossless.

  17. Femtosecond laser pulses for fast 3-D surface profilometry of microelectronic step-structures.

    Science.gov (United States)

    Joo, Woo-Deok; Kim, Seungman; Park, Jiyong; Lee, Keunwoo; Lee, Joohyung; Kim, Seungchul; Kim, Young-Jin; Kim, Seung-Woo

    2013-07-01

    Fast, precise 3-D measurement of discontinuous step-structures fabricated on microelectronic products is essential for quality assurance of semiconductor chips, flat panel displays, and photovoltaic cells. Optical surface profilers of low-coherence interferometry have long been used for the purpose, but the vertical scanning range and speed are limited by the micro-actuators available today. Besides, the lateral field-of-view extendable for a single measurement is restricted by the low spatial coherence of broadband light sources. Here, we cope with the limitations of the conventional low-coherence interferometer by exploiting unique characteristics of femtosecond laser pulses, i.e., low temporal but high spatial coherence. By scanning the pulse repetition rate with direct reference to the Rb atomic clock, step heights of ~69.6 μm are determined with a repeatability of 10.3 nm. The spatial coherence of femtosecond pulses provides a large field-of-view with superior visibility, allowing for a high volume measurement rate of ~24,000 mm3/s.

  18. Lateral step initiation behavior in older adults

    OpenAIRE

    Sparto, Patrick J; Jennings, J Richard; Furman, Joseph M; Redfern, Mark S

    2013-01-01

    Older adults have varied postural responses during induced and voluntary lateral stepping. The purpose of the research was to quantify the occurrence of different stepping strategies during lateral step initiation in older adults and to relate the stepping responses to retrospective history of falls. Seventy community-ambulating older adults (mean age 76 y, range 70–94 y) performed voluntary lateral steps as quickly as possible to the right or left in response to a visual cue, in a blocked de...

  19. Molecular dynamics simulation of the first electron transfer step in the oxygen reduction reaction

    NARCIS (Netherlands)

    Hartnig, C.B.; Koper, M.T.M.

    2002-01-01

    We present a molecular dynamics simulation of solvent reorganization in the first electron transfer step in the oxygen reduction reaction, i.e. O2+e-¿O2-, modeled as taking place in the outer Helmholtz plane. The first electron transfer step is usually considered the rate-determining step from many

  20. Limit load analysis of bolted flange connections

    International Nuclear Information System (INIS)

    Kauer, R.; Deininger, J.

    2005-01-01

    In Europe as well as in other countries a lot of efforts are invested into developing new codes and standards for bolted joints under various loading conditions. The standardization of gasket factors and the improvement of calculation methods with respect to these factors characterize the last couple of years in this area. In Germany, the nuclear code (KTA-Regeln) is also influenced by this development. So, the leak rate dependency of gasket factors and the results of a research program on metal-to-metal contact type flanges were introduced into the new approach of the code for Class 2 and 3 components. Herein; flange calculations can be performed for various flange types, floating type and metal-to-metal contact type. Generally, the calculations to be performed can be separated into a design step and the proof of sufficient tightness and strength of flange, bolts and gasket for the various operating conditions according to the chosen bolting method. In Europe, the most recent development in the field of flange calculations is the new standard EN 1591-1 for flange connections. The structure of the EN 1591-1 is also a two-step approach, but due to the more sophisticated and iterative calculation method, the design step is neglected and instead the focus in the first step is the determination of a suitable bolting force. In cases, where the allowable stress values are not satisfied by performing code calculations or in cases, where the applicability of the code is not given, e. g. due to geometric facts, Finite-Element analyses often replace code calculations but have to demonstrate code compliance. Therefore, numerical Finite-Element analyses, performed according to a special code, e. g. KTA, must also fulfill the requirements of the code with respect to considered load cases, bolting condition, allowable stresses etc., to get an adequate testimony for a certain flange joint. Usually this can be done by checking relevant cross sections according to the stress

  1. Biomechanical influences on balance recovery by stepping.

    Science.gov (United States)

    Hsiao, E T; Robinovitch, S N

    1999-10-01

    Stepping represents a common means for balance recovery after a perturbation to upright posture. Yet little is known regarding the biomechanical factors which determine whether a step succeeds in preventing a fall. In the present study, we developed a simple pendulum-spring model of balance recovery by stepping, and used this to assess how step length and step contact time influence the effort (leg contact force) and feasibility of balance recovery by stepping. We then compared model predictions of step characteristics which minimize leg contact force to experimentally observed values over a range of perturbation strengths. At all perturbation levels, experimentally observed step execution times were higher than optimal, and step lengths were smaller than optimal. However, the predicted increase in leg contact force associated with these deviations was substantial only for large perturbations. Furthermore, increases in the strength of the perturbation caused subjects to take larger, quicker steps, which reduced their predicted leg contact force. We interpret these data to reflect young subjects' desire to minimize recovery effort, subject to neuromuscular constraints on step execution time and step length. Finally, our model predicts that successful balance recovery by stepping is governed by a coupling between step length, step execution time, and leg strength, so that the feasibility of balance recovery decreases unless declines in one capacity are offset by enhancements in the others. This suggests that one's risk for falls may be affected more by small but diffuse neuromuscular impairments than by larger impairment in a single motor capacity.

  2. Rate of caesarean sections according to the Robson classification: Analysis in a French perinatal network - Interest and limitations of the French medico-administrative data (PMSI).

    Science.gov (United States)

    Lafitte, A-S; Dolley, P; Le Coutour, X; Benoist, G; Prime, L; Thibon, P; Dreyfus, M

    2018-02-01

    The objective of our study was to determine, in accordance with WHO recommendations, the rates of Caesarean sections in a French perinatal network according to the Robson classification and determine the benefit of the medico-administrative data (PMSI) to collect this indicator. This study aimed to identify the main groups contributing to local variations in the rates of Caesarean sections. A descriptive multicentric study was conducted in 13 maternity units of a French perinatal network. The rates of Caesarean sections and the contribution of each group of the Robson classification were calculated for all Caesarean sections performed in 2014. The agreement of the classification of Caesarean sections according to Robson using medico-administrative data and data collected in the patient records was measured by the Kappa index. We also analysed a 6 groups simplified Robson classification only using data from PMSI, which do not inform about parity and onset of labour. The rate of Caesarean sections was 19% (14.5-33.2) in 2014 (2924 out of 15413 deliveries). The most important contributors to the total rates were groups 1, 2 and 5, representing respectively 14.3%, 16.7% and 32.1% of the Caesarean sections. The rates were significantly different in level 1, 2b and 3 maternity units in groups 1 to 4, level 2a maternity units in group 5, and level 3 maternity units in groups 6 and 7. The agreement between the simplified Robson classification produced using the medical records and the medico-administrative data was excellent, with a Kappa index of 0.985 (0.980-0.990). To reduce the rates of Caesarean sections, audits should be conducted on groups 1, 2 and 5 and local protocols developed. Simply by collecting the parity data, the excellent metrological quality of the medico-administrative data would allow systematisation of the Robson classification for each hospital. Copyright © 2017. Published by Elsevier Masson SAS.

  3. The structure of stepped surfaces

    International Nuclear Information System (INIS)

    Algra, A.J.

    1981-01-01

    The state-of-the-art of Low Energy Ion Scattering (LEIS) as far as multiple scattering effects are concerned, is discussed. The ion fractions of lithium, sodium and potassium scattered from a copper (100) surface have been measured as a function of several experimental parameters. The ratio of the intensities of the single and double scattering peaks observed in ion scattering spectroscopy has been determined and ion scattering spectroscopy applied in the multiple scattering mode is used to determine the structure of a stepped Cu(410) surface. The average relaxation of the (100) terraces of this surface appears to be very small. The adsorption of oxygen on this surface has been studied with LEIS and it is indicated that oxygen absorbs dissociatively. (C.F.)

  4. A step toward nuclear sanity

    International Nuclear Information System (INIS)

    Gottfried, K.; Long, F.

    1988-01-01

    This paper reports that Reykjavik formally ended as a diplomatic failure, but it has begun an overdue revolution in perceptions. At long last, both superpowers have the in concrete terms that vastly smaller nuclear arsenals would make them safer. Implicitly, they are saying that nuclear weapons are not useful weapons. Those insights are a prerequisite to nuclear sanity. The United States has proposed to eliminate all strategic ballistic missiles, on land and submarines, in two five-year steps. During that period, we (and presumably the Soviet Union) would develop missile defenses to be deployed in ten years. The first part of this plan makes excellent sense. Ballistic missiles explode on their targets ten to thirty minutes after launch. Today's huge and accurate missile arsenals have forced both superpowers to adopt a hair-trigger stance: they might launch missiles simply on warning of attack

  5. Steps towards an evolutionary physics

    CERN Document Server

    Tiezzi, E

    2006-01-01

    If thermodynamics is to physics as logic is to philosophy, recent theoretical advancements lend new coherence to the marvel and dynamism of life on Earth. Enzo Tiezzi's "Steps Towards an Evolutionary Physics" is a primer and guide, to those who would to stand on the shoulders of giants to attain this view: Heisenberg, Planck, Bateson, Varela, and Prigogine as well as notable contemporary scientists. The adventure of such a free and enquiring spirit thrives not so much on answers as on new questions. The book offers a new gestalt on the uncertainty principle and concept of probability. A wide range of examples, enigmas, and paradoxes lead one's imagination on an exquisite dance. Among the applications are: songs and shapes of nature, oscillatory reactions, orientors, goal functions and configurations of processes, and "dissipative structures and the city". Ecodynamics is a new science, which proposes a cross-fertilization between Charles Darwin and Ilya Prigogine. As an enigma in thermodynamics, Entropy forms ...

  6. Boris push with spatial stepping

    International Nuclear Information System (INIS)

    Penn, G; Stoltz, P H; Cary, J R; Wurtele, J

    2003-01-01

    The Boris push is commonly used in plasma physics simulations because of its speed and stability. It is second-order accurate, requires only one field evaluation per time step, and has good conservation properties. However, for accelerator simulations it is convenient to propagate particles in z down a changing beamline. A 'spatial Boris push' algorithm has been developed which is similar to the Boris push but uses a spatial coordinate as the independent variable, instead of time. This scheme is compared to the fourth-order Runge-Kutta algorithm, for two simplified muon beam lattices: a uniform solenoid field, and a 'FOFO' lattice where the solenoid field varies sinusoidally along the axis. Examination of the canonical angular momentum, which should be conserved in axisymmetric systems, shows that the spatial Boris push improves accuracy over long distances

  7. Peyton’s four-step approach: differential effects of single instructional steps on procedural and memory performance – a clarification study

    Directory of Open Access Journals (Sweden)

    Krautter M

    2015-05-01

    Full Text Available Markus Krautter,1 Ronja Dittrich,2 Annette Safi,2 Justine Krautter,1 Imad Maatouk,2 Andreas Moeltner,2 Wolfgang Herzog,2 Christoph Nikendei2 1Department of Nephrology, 2Department of General Internal and Psychosomatic Medicine, University of Heidelberg Medical Hospital, Heidelberg, Germany Background: Although Peyton’s four-step approach is a widely used method for skills-lab training in undergraduate medical education and has been shown to be more effective than standard instruction, it is unclear whether its superiority can be attributed to a specific single step. Purpose: We conducted a randomized controlled trial to investigate the differential learning outcomes of the separate steps of Peyton’s four-step approach. Methods: Volunteer medical students were randomly assigned to four different groups. Step-1 group received Peyton’s Step 1, Step-2 group received Peyton’s Steps 1 and 2, Step-3 group received Peyton’s Steps 1, 2, and 3, and Step-3mod group received Peyton’s Steps 1 and 2, followed by a repetition of Step 2. Following the training, the first independent performance of a central venous catheter (CVC insertion using a manikin was video-recorded and scored by independent video assessors using binary checklists. The day after the training, memory performance during delayed recall was assessed with an incidental free recall test. Results: A total of 97 participants agreed to participate in the trial. There were no statistically significant group differences with regard to age, sex, completed education in a medical profession, completed medical clerkships, preliminary memory tests, or self-efficacy ratings. Regarding checklist ratings, Step-2 group showed a superior first independent performance of CVC placement compared to Step-1 group (P<0.001, and Step-3 group showed a superior performance to Step-2 group (P<0.009, while Step-2 group and Step-3mod group did not differ (P=0.055. The findings were similar in the incidental

  8. General methods for analysis of sequential "n-step" kinetic mechanisms: application to single turnover kinetics of helicase-catalyzed DNA unwinding.

    Science.gov (United States)

    Lucius, Aaron L; Maluf, Nasib K; Fischer, Christopher J; Lohman, Timothy M

    2003-10-01

    Helicase-catalyzed DNA unwinding is often studied using "all or none" assays that detect only the final product of fully unwound DNA. Even using these assays, quantitative analysis of DNA unwinding time courses for DNA duplexes of different lengths, L, using "n-step" sequential mechanisms, can reveal information about the number of intermediates in the unwinding reaction and the "kinetic step size", m, defined as the average number of basepairs unwound between two successive rate limiting steps in the unwinding cycle. Simultaneous nonlinear least-squares analysis using "n-step" sequential mechanisms has previously been limited by an inability to float the number of "unwinding steps", n, and m, in the fitting algorithm. Here we discuss the behavior of single turnover DNA unwinding time courses and describe novel methods for nonlinear least-squares analysis that overcome these problems. Analytic expressions for the time courses, f(ss)(t), when obtainable, can be written using gamma and incomplete gamma functions. When analytic expressions are not obtainable, the numerical solution of the inverse Laplace transform can be used to obtain f(ss)(t). Both methods allow n and m to be continuous fitting parameters. These approaches are generally applicable to enzymes that translocate along a lattice or require repetition of a series of steps before product formation.

  9. Preimages for Step-Reduced SHA-2

    DEFF Research Database (Denmark)

    Aoki, Kazumaro; Guo, Jian; Matusiewicz, Krystian

    2009-01-01

    In this paper, we present preimage attacks on up to 43-step SHA-256 (around 67% of the total 64 steps) and 46-step SHA-512 (around 57.5% of the total 80 steps), which significantly increases the number of attacked steps compared to the best previously published preimage attack working for 24 steps....... The time complexities are 2^251.9, 2^509 for finding pseudo-preimages and 2^254.9, 2^511.5 compression function operations for full preimages. The memory requirements are modest, around 2^6 words for 43-step SHA-256 and 46-step SHA-512. The pseudo-preimage attack also applies to 43-step SHA-224 and SHA-384...

  10. Stepping strategies for regulating gait adaptability and stability.

    Science.gov (United States)

    Hak, Laura; Houdijk, Han; Steenbrink, Frans; Mert, Agali; van der Wurff, Peter; Beek, Peter J; van Dieën, Jaap H

    2013-03-15

    Besides a stable gait pattern, gait in daily life requires the capability to adapt this pattern in response to environmental conditions. The purpose of this study was to elucidate the anticipatory strategies used by able-bodied people to attain an adaptive gait pattern, and how these strategies interact with strategies used to maintain gait stability. Ten healthy subjects walked in a Computer Assisted Rehabilitation ENvironment (CAREN). To provoke an adaptive gait pattern, subjects had to hit virtual targets, with markers guided by their knees, while walking on a self-paced treadmill. The effects of walking with and without this task on walking speed, step length, step frequency, step width and the margins of stability (MoS) were assessed. Furthermore, these trials were performed with and without additional continuous ML platform translations. When an adaptive gait pattern was required, subjects decreased step length (padaptations resulted in the preservation of equal MoS between trials, despite the disturbing influence of the gait adaptability task. When the gait adaptability task was combined with the balance perturbation subjects further decreased step length, as evidenced by a significant interaction between both manipulations (p=0.012). In conclusion, able-bodied people reduce step length and increase step width during walking conditions requiring a high level of both stability and adaptability. Although an increase in step frequency has previously been found to enhance stability, a faster movement, which would coincide with a higher step frequency, hampers accuracy and may consequently limit gait adaptability. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Linking pedestrian flow characteristics with stepping locomotion

    Science.gov (United States)

    Wang, Jiayue; Boltes, Maik; Seyfried, Armin; Zhang, Jun; Ziemer, Verena; Weng, Wenguo

    2018-06-01

    While properties of human traffic flow are described by speed, density and flow, the locomotion of pedestrian is based on steps. To relate characteristics of human locomotor system with properties of human traffic flow, this paper aims to connect gait characteristics like step length, step frequency, swaying amplitude and synchronization with speed and density and thus to build a ground for advanced pedestrian models. For this aim, observational and experimental study on the single-file movement of pedestrians at different densities is conducted. Methods to measure step length, step frequency, swaying amplitude and step synchronization are proposed by means of trajectories of the head. Mathematical models for the relations of step length or frequency and speed are evaluated. The problem how step length and step duration are influenced by factors like body height and density is investigated. It is shown that the effect of body height on step length and step duration changes with density. Furthermore, two different types of step in-phase synchronization between two successive pedestrians are observed and the influence of step synchronization on step length is examined.

  12. Space Drive Physics: Introduction and Next Steps

    Science.gov (United States)

    Millis, M. G.

    Research toward the visionary goal of propellantless ``space drives'' is introduced, covering key physics issues and a listing of roughly 2-dozen approaches. The targeted advantage of a space drive is to circumvent the propellant constraints of rockets and the maneuvering limits of light sails by using the interactions between the spacecraft and its surrounding space for propulsion. At present, the scientific foundations from which to engineer a space drive have not been discovered and, objectively, might be impossible. Although no propulsion breakthroughs appear imminent, the subject has matured to where the relevant questions have been broached and are beginning to be answered. The critical make-break issues include; conservation of momentum, uncertain sources of reaction mass, and the net-external thrusting requirement. Note: space drives are not necessarily faster- than-light devices. Speed limits are a separate, unanswered issue. Relevant unsolved physics includes; the sources and mechanisms of inertial frames, coupling of gravitation and electromagnetism, and the nature of the quantum vacuum. The propulsion approaches span mostly stages 1 through 3 of the scientific method (defining the problem, collecting data, and articulating hypotheses), while some have matured to stage 4 (testing hypotheses). Nonviable approaches include `stiction drives,' `gyroscopic antigravity,' and `lifters.' No attempt is made to gauge the prospects of the remaining approaches. Instead, a list of next-step research questions is derived from the examination of these goals, unknowns, and concepts.

  13. A Dimensionality Reduction-Based Multi-Step Clustering Method for Robust Vessel Trajectory Analysis

    Directory of Open Access Journals (Sweden)

    Huanhuan Li

    2017-08-01

    Full Text Available The Shipboard Automatic Identification System (AIS is crucial for navigation safety and maritime surveillance, data mining and pattern analysis of AIS information have attracted considerable attention in terms of both basic research and practical applications. Clustering of spatio-temporal AIS trajectories can be used to identify abnormal patterns and mine customary route data for transportation safety. Thus, the capacities of navigation safety and maritime traffic monitoring could be enhanced correspondingly. However, trajectory clustering is often sensitive to undesirable outliers and is essentially more complex compared with traditional point clustering. To overcome this limitation, a multi-step trajectory clustering method is proposed in this paper for robust AIS trajectory clustering. In particular, the Dynamic Time Warping (DTW, a similarity measurement method, is introduced in the first step to measure the distances between different trajectories. The calculated distances, inversely proportional to the similarities, constitute a distance matrix in the second step. Furthermore, as a widely-used dimensional reduction method, Principal Component Analysis (PCA is exploited to decompose the obtained distance matrix. In particular, the top k principal components with above 95% accumulative contribution rate are extracted by PCA, and the number of the centers k is chosen. The k centers are found by the improved center automatically selection algorithm. In the last step, the improved center clustering algorithm with k clusters is implemented on the distance matrix to achieve the final AIS trajectory clustering results. In order to improve the accuracy of the proposed multi-step clustering algorithm, an automatic algorithm for choosing the k clusters is developed according to the similarity distance. Numerous experiments on realistic AIS trajectory datasets in the bridge area waterway and Mississippi River have been implemented to compare our

  14. A Dimensionality Reduction-Based Multi-Step Clustering Method for Robust Vessel Trajectory Analysis.

    Science.gov (United States)

    Li, Huanhuan; Liu, Jingxian; Liu, Ryan Wen; Xiong, Naixue; Wu, Kefeng; Kim, Tai-Hoon

    2017-08-04

    The Shipboard Automatic Identification System (AIS) is crucial for navigation safety and maritime surveillance, data mining and pattern analysis of AIS information have attracted considerable attention in terms of both basic research and practical applications. Clustering of spatio-temporal AIS trajectories can be used to identify abnormal patterns and mine customary route data for transportation safety. Thus, the capacities of navigation safety and maritime traffic monitoring could be enhanced correspondingly. However, trajectory clustering is often sensitive to undesirable outliers and is essentially more complex compared with traditional point clustering. To overcome this limitation, a multi-step trajectory clustering method is proposed in this paper for robust AIS trajectory clustering. In particular, the Dynamic Time Warping (DTW), a similarity measurement method, is introduced in the first step to measure the distances between different trajectories. The calculated distances, inversely proportional to the similarities, constitute a distance matrix in the second step. Furthermore, as a widely-used dimensional reduction method, Principal Component Analysis (PCA) is exploited to decompose the obtained distance matrix. In particular, the top k principal components with above 95% accumulative contribution rate are extracted by PCA, and the number of the centers k is chosen. The k centers are found by the improved center automatically selection algorithm. In the last step, the improved center clustering algorithm with k clusters is implemented on the distance matrix to achieve the final AIS trajectory clustering results. In order to improve the accuracy of the proposed multi-step clustering algorithm, an automatic algorithm for choosing the k clusters is developed according to the similarity distance. Numerous experiments on realistic AIS trajectory datasets in the bridge area waterway and Mississippi River have been implemented to compare our proposed method with

  15. Comparative analysis of single-step and two-step biodiesel production using supercritical methanol on laboratory-scale

    International Nuclear Information System (INIS)

    Micic, Radoslav D.; Tomić, Milan D.; Kiss, Ferenc E.; Martinovic, Ferenc L.; Simikić, Mirko Ð.; Molnar, Tibor T.

    2016-01-01

    Highlights: • Single-step supercritical transesterification compared to the two-step process. • Two-step process: oil hydrolysis and subsequent supercritical methyl esterification. • Experiments were conducted in a laboratory-scale batch reactor. • Higher biodiesel yields in two-step process at milder reaction conditions. • Two-step process has potential to be cost-competitive with the single-step process. - Abstract: Single-step supercritical transesterification and two-step biodiesel production process consisting of oil hydrolysis and subsequent supercritical methyl esterification were studied and compared. For this purpose, comparative experiments were conducted in a laboratory-scale batch reactor and optimal reaction conditions (temperature, pressure, molar ratio and time) were determined. Results indicate that in comparison to a single-step transesterification, methyl esterification (second step of the two-step process) produces higher biodiesel yields (95 wt% vs. 91 wt%) at lower temperatures (270 °C vs. 350 °C), pressures (8 MPa vs. 12 MPa) and methanol to oil molar ratios (1:20 vs. 1:42). This can be explained by the fact that the reaction system consisting of free fatty acid (FFA) and methanol achieves supercritical condition at milder reaction conditions. Furthermore, the dissolved FFA increases the acidity of supercritical methanol and acts as an acid catalyst that increases the reaction rate. There is a direct correlation between FFA content of the product obtained in hydrolysis and biodiesel yields in methyl esterification. Therefore, the reaction parameters of hydrolysis were optimized to yield the highest FFA content at 12 MPa, 250 °C and 1:20 oil to water molar ratio. Results of direct material and energy costs comparison suggest that the process based on the two-step reaction has the potential to be cost-competitive with the process based on single-step supercritical transesterification. Higher biodiesel yields, similar or lower energy

  16. Thermal sensation and thermophysiological responses with metabolic step-changes

    DEFF Research Database (Denmark)

    Goto, Tomonobu; Toftum, Jørn; deDear, Richard

    2006-01-01

    at sedentary activity. In a second experimental series, subjects alternated between rest and exercise as well as between exercise at different intensities at two temperature levels. Measurements comprised skin and oesophageal temperatures, heart rate and subjective responses. Thermal sensation started to rise....... The sensitivity of thermal sensation to changes in core temperature was higher for activity down-steps than for up-steps. A model was proposed that estimates transient thermal sensation after metabolic step-changes. Based on predictions by the model, weighting factors were suggested to estimate a representative...... average metabolic rate with varying activity levels, e.g. for the prediction of thermal sensation by steady-state comfort models. The activity during the most recent 5 min should be weighted 65%, during the prior 10-5 min 25% and during the prior 20-10 min 10%....

  17. Kinematic and behavioral analyses of protective stepping strategies and risk for falls among community living older adults.

    Science.gov (United States)

    Bair, Woei-Nan; Prettyman, Michelle G; Beamer, Brock A; Rogers, Mark W

    2016-07-01

    Protective stepping evoked by externally applied lateral perturbations reveals balance deficits underlying falls. However, a lack of comprehensive information about the control of different stepping strategies in relation to the magnitude of perturbation limits understanding of balance control in relation to age and fall status. The aim of this study was to investigate different protective stepping strategies and their kinematic and behavioral control characteristics in response to different magnitudes of lateral waist-pulls between older fallers and non-fallers. Fifty-two community-dwelling older adults (16 fallers) reacted naturally to maintain balance in response to five magnitudes of lateral waist-pulls. The balance tolerance limit (BTL, waist-pull magnitude where protective steps transitioned from single to multiple steps), first step control characteristics (stepping frequency and counts, spatial-temporal kinematic, and trunk position at landing) of four naturally selected protective step types were compared between fallers and non-fallers at- and above-BTL. Fallers took medial-steps most frequently while non-fallers most often took crossover-back-steps. Only non-fallers varied their step count and first step control parameters by step type at the instants of step initiation (onset time) and termination (trunk position), while both groups modulated step execution parameters (single stance duration and step length) by step type. Group differences were generally better demonstrated above-BTL. Fallers primarily used a biomechanically less effective medial-stepping strategy that may be partially explained by reduced somato-sensation. Fallers did not modulate their step parameters by step type at first step initiation and termination, instances particularly vulnerable to instability, reflecting their limitations in balance control during protective stepping. Copyright © 2016. Published by Elsevier Ltd.

  18. Teaching Softball. Steps to Success.

    Science.gov (United States)

    Potter, Diane L.; Brockmeyer, Gretchen A.

    This handbook was written for the instructor of softball. It is a comprehensive guide for individualizing and improving instruction. Essential instructional resources are provided, including: (1) management and safety guidelines; (2) warm-up and cool-down exercises; (3) specification of equipment needs; (4) rating charts for identifying students'…

  19. Performance of the Seven-step Procedure in Problem-based Hospitality Management Education

    Directory of Open Access Journals (Sweden)

    Wichard Zwaal

    2016-12-01

    Full Text Available The study focuses on the seven-step procedure (SSP in problem-based learning (PBL. The way students apply the seven-step procedure will help us understand how students work in a problem-based learning curriculum. So far, little is known about how students rate the performance and importance of the different steps, the amount of time they spend on each step and the perceived quality of execution of the procedure. A survey was administered to a sample of 101 students enrolled in a problem-based hospitality management program. Results show that students consider step 6 (Collect additional information outside the group to be most important. The highest performance-rating is for step two (Define the problem and the lowest for step four (Draw a systemic inventory of explanations from step three. Step seven is classified as low in performance and high in importance implicating urgent attention. The average amount of time spent on the seven steps is 133 minutes with the largest part of the time spent on self-study outside the group (42 minutes. The assessment of the execution of a set of specific guidelines (the Blue Card did not completely match with the overall performance ratings for the seven steps. The SSP could be improved by reducing the number of steps and incorporating more attention to group dynamics.

  20. Thermodynamic approach and comparison of two-step and single step DME (dimethyl ether) syntheses with carbon dioxide utilization

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Hsu, Chih-Liang; Wang, Xiao-Dong

    2016-01-01

    DME (Dimethyl ether) synthesis from syngas with CO_2 utilization through two-step and single step processes is analyzed thermodynamically. The influences of reaction temperature, H_2/CO molar ratio, and CO_2/CO molar ratio on CO and CO_2 conversions, DME selectivity and yield, and thermal behavior are evaluated. Particular attention is paid to the comparison of the performance of DME synthesis between the two different methods. In the two-step method, the addition of CO_2 suppresses the CO conversion during methanol synthesis. An increase in CO_2/CO ratio decreases the CO_2 conversion (negative effect), but increases the total consumption amount of CO_2 (positive effect). At a given reaction temperature with H_2/CO = 4, the maximum DME yield develops at CO_2/CO = 1. In the single step method, over 98% of CO can be converted and the DME yield can be as high as 0.52 mol (mol CO)"−"1 at CO_2/CO = 2. The comparison of the single step and two-step processes indicates that the maximum CO conversion, DME selectivity, and DME yield in the former are higher than those in the latter, whereas an opposite result in the maximum CO_2 conversion is observed. These results reveal that the single step process has lower thermodynamic limitation and is a better option for DME synthesis. From CO_2 utilization point of view, the operation with low temperature, high H_2/CO ratio, and low CO_2/CO ratio results in higher CO_2 conversion, irrespective of two-step or single step DME synthesis. - Highlights: • DME (Dimethyl ether) synthesis with CO_2 utilization is analyzed thermodynamically. • Single step and two-step DME syntheses are studied and compared with each other. • CO_2 addition suppresses CO conversion in MeOH synthesis but increases MeOH yield. • The performance of the single step DME synthesis is better than that of the two-step one. • Increase CO_2/CO ratio decreases CO_2 conversion but increases CO_2 consumption amount.

  1. An overview on STEP-NC compliant controller development

    Science.gov (United States)

    Othman, M. A.; Minhat, M.; Jamaludin, Z.

    2017-10-01

    The capabilities of conventional Computer Numerical Control (CNC) machine tools as termination organiser to fabricate high-quality parts promptly, economically and precisely are undeniable. To date, most CNCs follow the programming standard of ISO 6983, also called G & M code. However, in fluctuating shop floor environment, flexibility and interoperability of current CNC system to react dynamically and adaptively are believed still limited. This outdated programming language does not explicitly relate to each other to have control of arbitrary locations other than the motion of the block-by-block. To address this limitation, new standard known as STEP-NC was developed in late 1990s and is formalized as an ISO 14649. It adds intelligence to the CNC in term of interoperability, flexibility, adaptability and openness. This paper presents an overview of the research work that have been done in developing a STEP-NC controller standard and the capabilities of STEP-NC to overcome modern manufacturing demands. Reviews stated that most existing STEP-NC controller prototypes are based on type 1 and type 2 implementation levels. There are still lack of effort being done to develop type 3 and type 4 STEP-NC compliant controller.

  2. Multi-step direct reactions

    International Nuclear Information System (INIS)

    Koning, A.J.

    1992-07-01

    In recent years a variety of statistical theories has been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton models'; these are basically MSD-type extensions on top of compound-like concepts. In this report the relation between their underlying statistical MSD-postulates are highlighted. A command framework is sketched that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high energy-tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imagined that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expression for MSD emission cross sections. This picture suggests that mentioned MSD models can be interpreted as a variant of essentially one and the same theory. 113 refs.; 25 figs.; 9 tabs

  3. Five steps to increasing utilization of your Employee Assistance Program.

    Science.gov (United States)

    Carchietta, Gail A

    2015-03-01

    Despite increased stress and free services, the national average for EAP use within a company continues to be 3% to 4%. This article describes the steps one company has taken to achieve a 16% utilization rate for the last 3 years. © 2015 The Author(s).

  4. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step...... length, step height, and.flux start level. Filtrating 8 kg/m(3) yeast cell suspensions by a vibrating 0.45 x 10(-6) m pore size microfiltration hollow fiber module, critical fluxes from 5.6 x 10(-6) to 1.2 x 10(-5) m/s have been measured using various step lengths from 300 to 1200 seconds. Thus......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  5. Step dynamics and terrace-width distribution on flame-annealed gold films: The effect of step-step interaction

    International Nuclear Information System (INIS)

    Shimoni, Nira; Ayal, Shai; Millo, Oded

    2000-01-01

    Dynamics of atomic steps and the terrace-width distribution within step bunches on flame-annealed gold films are studied using scanning tunneling microscopy. The distribution is narrower than commonly observed for vicinal planes and has a Gaussian shape, indicating a short-range repulsive interaction between the steps, with an apparently large interaction constant. The dynamics of the atomic steps, on the other hand, appear to be influenced, in addition to these short-range interactions, also by a longer-range attraction of steps towards step bunches. Both types of interactions promote self-ordering of terrace structures on the surface. When current is driven through the films a step-fingering instability sets in, reminiscent of the Bales-Zangwill instability

  6. Ten steps to successful software process improvement

    Science.gov (United States)

    Kandt, R. K.

    2003-01-01

    This paper identifies ten steps for managing change that address organizational and cultural issues. Four of these steps are critical, that if not done, will almost guarantee failure. This ten-step program emphasizes the alignment of business goals, change process goals, and the work performed by the employees of an organization.

  7. 7 CFR 65.230 - Production step.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Production step. 65.230 Section 65.230 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards..., PEANUTS, AND GINSENG General Provisions Definitions § 65.230 Production step. Production step means, in...

  8. Origins Space Telescope: Breaking the Confusion Limit

    Science.gov (United States)

    Wright, Edward L.; Origins Space Telescope Science and Technology Definition Team

    2018-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s.OST will have a background-limited sensitivity for a background 27,000 times lower than the Herschel background caused by thermal emission from Herschel's warm telescope. For continuum observations the confusion limit in a diffraction-limited survey can be reached in very short integration times at longer far-infrared wavelengths. But the confusion limit can be pierced for both the nearest and the farthest objects to be observed by OST. For outer the Solar System the targets' motion across the sky will provide a clear signature in surveys repeated after an interval of days to months. This will provide a size-frequency distribution of TNOs that is not biased toward high albedo objects.For the distant Universe the first galaxies and the first metals will provide a third dimension of spectral information that can be measured with a long-slit, medium resolution spectrograph. This will allow 3Dmapping to measure source densities as a function of redshift. The continuum shape associated with sourcesat different redshifts can be derived from correlation analyses of these 3D maps.Fairly large sky areas can be scanned by moving the spacecraft at a constant angular rate perpendicular to the orientation of the long slit of the spectrograph, avoiding the high overhead of step-and-stare surveying with a large space observatory.We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at ost_info@lists.ipac.caltech.edu

  9. Traffic safety and step-by-step driving licence for young people

    DEFF Research Database (Denmark)

    Tønning, Charlotte; Agerholm, Niels

    2017-01-01

    presents a review of safety effects from step-by-step driving licence schemes. Most of the investigated schemes consist of a step-by-step driving licence with Step 1) various tests and education, Step 2) a period where driving is only allowed together with an experienced driver and Step 3) driving without...... companion is allowed but with various restrictions and, in some cases, additional driving education and tests. In general, a step-by-step driving licence improves traffic safety even though the young people are permitted to drive a car earlier on. The effects from driving with an experienced driver vary......Young novice car drivers are much more accident-prone than other drivers - up to 10 times that of their parents' generation. A central solution to improve the traffic safety for this group is implementation of a step-by-step driving licence. A number of countries have introduced a step...

  10. Required Steps of Managing International Equity Placement Strategic Alliance

    Directory of Open Access Journals (Sweden)

    Harimukti Wandebori

    2012-01-01

    Full Text Available The purpose of the research is to unravel the steps of managing international equity placement strategic alliance (IEPSA. The steps of managing an IEPSA are obtained by conducting theoretical review. The theoretical reviews consist of theory of strategic alliance; definition, classification, and finding definition of an IEPSA, political and analytical considerations and the necessary steps. These steps of managing IEPSA can be classified into analyzing of macro consideration, micro consideration, domestic company’s stakeholder support, cultural understanding, strategic planning, internal support, human resource management, organizational arrangement, management control system, evolved cultural understanding, and evaluating results. In this research, the domestic partners who formed the IEPSAs are limited to State-Owned Enterprises (SOEs. The IEPSA was one of the means of privatization. The research will be beneficial for both foreign and domestic partners who form an IEPSA in the previous SOEs. By knowing the steps of managing the IEPSA both partners will be able to secure a successful implementation of IEPSA. By identifying the steps of managing the IEPSA, the stakeholder will not see IEPSA as threat rather as an opportunity to improve performance, to create synergy, and generate benefits for both partners and stakeholder. By knowing the necessary steps of managing the IEPSA, the stakeholder including society and politician will envisage the IEPSA as a means of effectively improving the SOEs’ performances.The research was espected to provide contributions for the research on strategic alliances. Apparently, there exist no literatures discussing about IEPSA in the domain of strategic alliances. Keywords: strategic alliance, equity placement, international equity placement strategic alliance, privatization, steps of international equity placement strategic alliance, state-owned enterprises

  11. Landscape response to tipping points in granite weathering: The case of stepped topography in the Southern Sierra Critical Zone Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Jessup, Barbara S.; Jesse Hahm, W. [Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071 (United States); Miller, Scott N. [Department of Renewable Resources, University of Wyoming, Laramie, WY 82071 (United States); Kirchner, James W. [Swiss Federal Institute for Forest, Snow and Landscape Research, Zuercherstrasse 111, CH-8903 Birmensdorf (Switzerland)] [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States); Riebe, Clifford S., E-mail: criebe@uwyo.edu [Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071 (United States)

    2011-06-15

    Highlights: > This work tests a decades-old hypothesis in which relief development in the southern Sierra Nevada is attributed to differential weathering of bare and soil-mantled granite. > Terrain analysis shows that the landscape is organized into a sequence of steep steps and gentle treads, consistent with the hypothesis. > Cosmogenic nuclides show that bare granite erodes more slowly than its soil-mantled counterparts, as required by the hypothesis.However, steps erode more quickly than treads, undermining the explanation for the origins of the stepped topography. - Abstract: The dynamics of granitic landscapes are modulated by bimodal weathering, which produces patchy granular soils and expanses of bare rock ranging from meter-scale boulders to mountain-scale domes. We used terrain analysis and with cosmogenic nuclide measurements of erosion rates to quantitatively explore Wahrhaftig's decades-old hypothesis for the development of 'stepped topography' by differential weathering of bare and soil-mantled granite. According to Wahrhaftig's hypothesis, bare granite weathers slower than soil-mantled granite; thus random erosional exposure of bare rock leads to an alternating sequence of steep, slowly weathering bedrock 'steps' and gently sloped, but rapidly weathering, soil-mantled 'treads.' Our investigation focused on the terrain surrounding the Southern Sierra Critical Zone Observatory (CZO), which is underlain by granitic bedrock and lies outside the limits of recent glaciation, in the heart of the stepped topography described by Wahrhaftig. Our digital terrain analysis confirms that steep steps often grade into gentle treads, consistent with Wahrhaftig's hypothesis. However, we observe a mix-and-match of soil and bare rock on treads and steps, contrary to one of the hypothesis' major underpinnings - that bare rock should be much more common on steps than on treads. Moreover, the data show that bare rock is not

  12. Atomic Step Formation on Sapphire Surface in Ultra-precision Manufacturing

    Science.gov (United States)

    Wang, Rongrong; Guo, Dan; Xie, Guoxin; Pan, Guoshun

    2016-01-01

    Surfaces with controlled atomic step structures as substrates are highly relevant to desirable performances of materials grown on them, such as light emitting diode (LED) epitaxial layers, nanotubes and nanoribbons. However, very limited attention has been paid to the step formation in manufacturing process. In the present work, investigations have been conducted into this step formation mechanism on the sapphire c (0001) surface by using both experiments and simulations. The step evolutions at different stages in the polishing process were investigated with atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). The simulation of idealized steps was constructed theoretically on the basis of experimental results. It was found that (1) the subtle atomic structures (e.g., steps with different sawteeth, as well as steps with straight and zigzag edges), (2) the periodicity and (3) the degree of order of the steps were all dependent on surface composition and miscut direction (step edge direction). A comparison between experimental results and idealized step models of different surface compositions has been made. It has been found that the structure on the polished surface was in accordance with some surface compositions (the model of single-atom steps: Al steps or O steps). PMID:27444267

  13. Advantages and limitations of the SETS method

    International Nuclear Information System (INIS)

    Mahaffy, J.H.

    1983-01-01

    The stability-enchancing two-step (SETS) method has been used successfully in the Transient Reactor Analysis Code (TRAC) for several years. The method consists of a basic semi-implicit step combined with a stabilizer step that, taken together, eliminate the material Courant stability limit associated with standard semi-implicit numerical methods. This approach toward stability requires significantly fewer computational operations than a fully implicit method, but currently maintains the first-order accuracy in space and time of its semi-implicit predecessors

  14. A simple one-step chemistry model for partially premixed hydrocarbon combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Tarrazo, Eduardo [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Sanchez, Antonio L. [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Linan, Amable [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2006-10-15

    This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T{sub a}, and the preexponential factor B. It is seen that changes in q with equivalence ratio f need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(f) for f>1 for all hydrocarbons. The model also employs a variable activation temperature T{sub a}(f) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (author)

  15. A one-step, real-time PCR assay for rapid detection of rhinovirus.

    Science.gov (United States)

    Do, Duc H; Laus, Stella; Leber, Amy; Marcon, Mario J; Jordan, Jeanne A; Martin, Judith M; Wadowsky, Robert M

    2010-01-01

    One-step, real-time PCR assays for rhinovirus have been developed for a limited number of PCR amplification platforms and chemistries, and some exhibit cross-reactivity with genetically similar enteroviruses. We developed a one-step, real-time PCR assay for rhinovirus by using a sequence detection system (Applied Biosystems; Foster City, CA). The primers were designed to amplify a 120-base target in the noncoding region of picornavirus RNA, and a TaqMan (Applied Biosystems) degenerate probe was designed for the specific detection of rhinovirus amplicons. The PCR assay had no cross-reactivity with a panel of 76 nontarget nucleic acids, which included RNAs from 43 enterovirus strains. Excellent lower limits of detection relative to viral culture were observed for the PCR assay by using 38 of 40 rhinovirus reference strains representing different serotypes, which could reproducibly detect rhinovirus serotype 2 in viral transport medium containing 10 to 10,000 TCID(50) (50% tissue culture infectious dose endpoint) units/ml of the virus. However, for rhinovirus serotypes 59 and 69, the PCR assay was less sensitive than culture. Testing of 48 clinical specimens from children with cold-like illnesses for rhinovirus by the PCR and culture assays yielded detection rates of 16.7% and 6.3%, respectively. For a batch of 10 specimens, the entire assay was completed in 4.5 hours. This real-time PCR assay enables detection of many rhinovirus serotypes with the Applied Biosystems reagent-instrument platform.

  16. Variable Step Size Maximum Correntropy Criteria Based Adaptive Filtering Algorithm

    Directory of Open Access Journals (Sweden)

    S. Radhika

    2016-04-01

    Full Text Available Maximum correntropy criterion (MCC based adaptive filters are found to be robust against impulsive interference. This paper proposes a novel MCC based adaptive filter with variable step size in order to obtain improved performance in terms of both convergence rate and steady state error with robustness against impulsive interference. The optimal variable step size is obtained by minimizing the Mean Square Deviation (MSD error from one iteration to the other. Simulation results in the context of a highly impulsive system identification scenario show that the proposed algorithm has faster convergence and lesser steady state error than the conventional MCC based adaptive filters.

  17. Rate of accumulation of thymidine analogue mutations in patients continuing to receive virologically failing regimens containing zidovudine or stavudine: implications for antiretroviral therapy programs in resource-limited settings

    DEFF Research Database (Denmark)

    Cozzi-Lepri, Alessandro; Phillips, Andrew N; Martinez-Picado, Javier

    2009-01-01

    BACKGROUND: Because changes in antiretroviral therapy in resource-limited settings (RLSs) are delayed until patients experience immunological or clinical failure, it is important to be able to estimate the consequences in terms of accumulation of thymidine analogue (TA) mutations (TAMs). METHODS...... until the second GRT. RESULTS: At the time of the first GRT in a pair (t0), 1 year after virological failure, a median of 3 TAMs were detected, mutations 41L and 215Y in 65% of pairs and 67N in 52%. Overall, 126 TAMs were accumulated during 548 person-years of follow-up (PYFUs) (1/4.3 years; 95......% confidence interval, 3.7-5.0 years). Greater predicted activity of the TA at t0, TAM profile 2 (TAM2; vs TAM profile 1 [TAM1]) profiles at t0, use of a nonnucleoside reverse-transcriptase inhibitor (NNRTI) at t0 (vs combined NNRTI and protease inhibitor), and acquisition of HIV infection through heterosexual...

  18. One step processing for future diesel specifications

    International Nuclear Information System (INIS)

    Brierley, G.R.

    1997-01-01

    The trend in diesel fuel specifications is to limit the sulfur level to less than 0.05 wt- per cent. Many regions have also specified that diesel fuels must have lower aromatic levels, higher cetane numbers, and lower distillation end points. These changes will require significant refinery investment to meet the new diesel fuel specifications. The changes may also significantly affect the value of synthetic crude stocks. UOP has developed a new hydroprocessing catalyst which makes it possible to meet the new diesel specifications in one single processing step and at minimal cost. The catalyst saturates aromatics while opening ring structures at the same time. By selectively cracking heavy components into the diesel range with minimal cracking to gas or naphtha, heavier feedstocks can be upgraded to diesel, and refinery diesel yield can be augmented. Synthetic crude distillate is often high in aromatics and low in cetane number. This new UOP hydroprocessing system will allow synthetic crude producers and refiners to produce diesel fuels with higher cetane numbers, high-quality distillate blendstocks and distillate fuels. 26 figs

  19. Rate of Threading a Cellulose Chain into the Binding Tunnel of a Cellulase

    DEFF Research Database (Denmark)

    Cruys-Bagger, Nicolaj; Alasepp, Kadri; Andersen, Morten

    2016-01-01

    the tunnel with a cellulose strand and end with the opposite, that is, the dethreading process. Evidence has suggested that threading or dethreading may be rate-limiting for the overall enzyme reaction. To directly elucidate the rates of threading and dethreading, we analyzed experimental data with respect......, at which other steps also influenced the overall dynamics. These results will be helpful in identifying rate-limiting steps for cellulases and, in turn, targets for rational design of faster enzymes.......Industrially important cellulase Cel7A hydrolyzes crystalline cellulose by a complex processive mechanism in which the enzyme slides along the cellulose surface with one strand of the polymeric substrate channeled through its catalytic tunnel. Each processive run must start with threading...

  20. Step-grandparenthood in the United States.

    Science.gov (United States)

    Yahirun, Jenjira J; Park, Sung S; Seltzer, Judith A

    2018-01-18

    This study provides new information about the demography of step-grandparenthood in the United States. Specifically, we examine the prevalence of step-grandparenthood across birth cohorts and for socioeconomic and racial/ethnic groups. We also examine lifetime exposure to the step-grandparent role. Using data from the Panel Study of Income Dynamics and the Health and Retirement Study, we use percentages to provide first estimates of step-grandparenthood and to describe demographic and socioeconomic variation in who is a step-grandparent. We use life tables to estimate the exposure to step-grandparenthood. The share of step-grandparents is increasing across birth cohorts. However, individuals without a college education and non-Whites are more likely to become step-grandparents. Exposure to the step-grandparent role accounts for approximately 15% of total grandparent years at age 65 for women and men. A growing body of research finds that grandparents are increasingly instrumental in the lives of younger generations. However, the majority of this work assumes that these ties are biological, with little attention paid to the role of family complexity across three generations. Understanding the demographics of step-grandparenthood sheds light on the family experiences of an overlooked, but growing segment of the older adult population in the United States. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Step-by-Step Model for the Study of the Apriori Algorithm for Predictive Analysis

    Directory of Open Access Journals (Sweden)

    Daniel Grigore ROŞCA

    2015-06-01

    Full Text Available The goal of this paper was to develop an educational oriented application based on the Data Mining Apriori Algorithm which facilitates both the research and the study of data mining by graduate students. The application could be used to discover interesting patterns in the corpus of data and to measure the impact on the speed of execution as a function of problem constraints (value of support and confidence variables or size of the transactional data-base. The paper presents a brief overview of the Apriori Algorithm, aspects about the implementation of the algorithm using a step-by-step process, a discussion of the education-oriented user interface and the process of data mining of a test transactional data base. The impact of some constraints on the speed of the algorithm is also experimentally measured without a systematic review of different approaches to increase execution speed. Possible applications of the implementation, as well as its limits, are briefly reviewed.

  2. Non-linear analysis of solid propellant burning rate behavior

    Energy Technology Data Exchange (ETDEWEB)

    Junye Wang [Zhejiang Univ. of Technology, College of Mechanical and Electrical Engineering, Hanzhou (China)

    2000-07-01

    The parametric analysis of the thermal wave model of the non-steady combustion of solid propellants is carried out under a sudden compression. First, to observe non-linear effects, solutions are obtained using a computer under prescribed pressure variations. Then, the effects of rearranging the spatial mesh, additional points, and the time step on numerical solutions are evaluated. Finally, the behaviour of the thermal wave combustion model is examined under large heat releases (H) and a dynamic factor ({beta}). The numerical predictions show that (1) the effect of a dynamic factor ({beta}), related to the magnitude of dp/dt, on the peak burning rate increases as the value of beta increases. However, unsteady burning rate 'runaway' does not appear and will return asymptotically to ap{sup n}, when {beta}{>=}10.0. The burning rate 'runaway' is a numerical difficulty, not a solution to the models. (2) At constant beta and m, the amplitude of the burning rate increases with increasing H. However, the increase in the burning rate amplitude is stepwise, and there is no apparent intrinsic instability limit. A damped oscillation of burning rate occurs when the value of H is less. However, when H>1.0, the state of an intrinsically unstable model is composed of repeated, amplitude spikes, i.e. an undamped oscillation occurs. (3) The effect of the time step on the peak burning rate increases as H increases. (Author)

  3. The availability of the step optimization in Monaco planning system

    International Nuclear Information System (INIS)

    Kim, Dae Sup

    2014-01-01

    We present a method to reduce this gap and complete the treatment plan, to be made by the re-optimization is performed in the same conditions as the initial treatment plan different from Monaco treatment planning system. The optimization is carried in two steps when performing the inverse calculation for volumetric modulated radiation therapy or intensity modulated radiation therapy in Monaco treatment planning system. This study was the first plan with a complete optimization in two steps by performing all of the treatment plan, without changing the optimized condition from Step 1 to Step 2, a typical sequential optimization performed. At this time, the experiment was carried out with a pencil beam and Monte Carlo algorithm is applied In step 2. We compared initial plan and re-optimized plan with the same optimized conditions. And then evaluated the planning dose by measurement. When performing a re-optimization for the initial treatment plan, the second plan applied the step optimization. When the common optimization again carried out in the same conditions in the initial treatment plan was completed, the result is not the same. From a comparison of the treatment planning system, similar to the dose-volume the histogram showed a similar trend, but exhibit different values that do not satisfy the conditions best optimized dose, dose homogeneity and dose limits. Also showed more than 20% different in comparison dosimetry. If different dose algorithms, this measure is not the same out. The process of performing a number of trial and error, and you get to the ultimate goal of treatment planning optimization process. If carried out to optimize the completion of the initial trust only the treatment plan, we could be made of another treatment plan. The similar treatment plan could not satisfy to optimization results. When you perform re-optimization process, you will need to apply the step optimized conditions, making sure the dose distribution through the optimization

  4. A theoretical model investigation of peptide bond formation involving two water molecules in ribosome supports the two-step and eight membered ring mechanism

    International Nuclear Information System (INIS)

    Wang, Qiang; Gao, Jun; Zhang, Dongju; Liu, Chengbu

    2015-01-01

    Highlights: • We theoretical studied peptide bond formation reaction mechanism with two water molecules. • The first water molecule can decrease the reaction barriers by forming hydrogen bonds. • The water molecule mediated three-proton transfer mechanism is the favorable mechanism. • Our calculation supports the two-step and eight membered ring mechanism. - Abstract: The ribosome is the macromolecular machine that catalyzes protein synthesis. The kinetic isotope effect analysis reported by Strobel group supports the two-step mechanism. However, the destination of the proton originating from the nucleophilic amine is uncertain. A computational simulation of different mechanisms including water molecules is carried out using the same reaction model and theoretical level. Formation the tetrahedral intermediate with proton transfer from nucleophilic nitrogen, is the rate-limiting step when two water molecules participate in peptide bond formation. The first water molecule forming hydrogen bonds with O9′ and H15′ in the A site can decrease the reaction barriers. Combined with results of the solvent isotope effects analysis, we conclude that the three-proton transfer mechanism in which water molecule mediate the proton shuttle between amino and carbon oxygen in rate-limiting step is the favorable mechanism. Our results will shield light on a better understand the reaction mechanism of ribosome

  5. Real Convergence, Steps from Adherence to Integration

    Directory of Open Access Journals (Sweden)

    Mihail Busu

    2016-05-01

    Full Text Available The macroeconomic model Solow-Swan shows that the marginal rates of capital, technology and labor force, with positive values, have the capacity to stimulate the economic growth of the emergent economies, as in the case of Romania, for the 2005-2014 period, facilitating the determination of specific correlations between macroeconomic indicators to analyze the convergence towards the average European Union (EU. The economic theory, highlighted in particular by the Solow-Swan model, was applied in the current paper, to determine the potential of real convergence. Moreover, the statistics for the period 2005-2014 facilitated the analysis of the growth and recession factors specific to economies of Central and Eastern Europe and placed Romania amongst the EU countries with emergent economies and potential of economic growth. The European Commission’s reports regarding the macroeconomic imbalance procedure draw attention on the same indicators presented in the article to address proper recommendations and support corrective measures. Making a step from nominal to real convergence, the latter derives naturally from the need to recoup the gaps in comparison with developed economies amongst countries of the Euro Area.

  6. DEVELOPMENT OF HOLE RECOGNITION SYSTEM FROM STEP FILE

    Directory of Open Access Journals (Sweden)

    C. F. Tan

    2017-11-01

    Full Text Available This paper describes the development of Hole Recognition System (HRS for Computer-Aided Process Planning (CAPP using a neutral data format produced by CAD system. The geometrical data of holes is retrieved from STandard for the Exchange of Product model data (STEP. Rule-based algorithm is used during recognising process. Current implementation of feature recognition is limited to simple hole feat ures. Test results are presented to demonstrate the capabilities of the feature recognition algorithm.

  7. Six steps to a successful dose-reduction strategy

    International Nuclear Information System (INIS)

    Bennett, M.

    1995-01-01

    The increased importance of demonstrating achievement of the ALARA principle has helped produce a proliferation of dose-reduction ideas. Across a company there may be many dose-reduction items being pursued in a variety of areas. However, companies have a limited amount of resource and, therefore, to ensure funding is directed to those items which will produce the most benefit and that all areas apply a common policy, requires the presence of a dose-reduction strategy. Six steps were identified in formulating the dose-reduction strategy for Rolls-Royce and Associates (RRA): (1) collating the ideas; (2) quantitatively evaluating them on a common basis; (3) prioritizing the ideas in terms of cost benefit, (4) implementation of the highest priority items; (5) monitoring their success; (6) periodically reviewing the strategy. Inherent in producing the dose-reduction strategy has been a comprehensive dose database and the RRA-developed dose management computer code DOMAIN, which allows prediction of dose rates and dose. The database enabled high task dose items to be identified, assisted in evaluating dose benefits, and monitored dose trends once items had been implemented. The DOMAIN code was used both in quantifying some of the project dose benefits and its results, such as dose contours, used in some of the dose-reduction items themselves. In all, over fifty dose-reduction items were evaluated in the strategy process and the items which will give greatest benefit are being implemented. The strategy has been successful in giving renewed impetus and direction to dose-reduction management

  8. Six steps to a successful dose-reduction strategy

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, M. [Rolls-Royce & Associates Ltd., Derby (United Kingdom)

    1995-03-01

    The increased importance of demonstrating achievement of the ALARA principle has helped produce a proliferation of dose-reduction ideas. Across a company there may be many dose-reduction items being pursued in a variety of areas. However, companies have a limited amount of resource and, therefore, to ensure funding is directed to those items which will produce the most benefit and that all areas apply a common policy, requires the presence of a dose-reduction strategy. Six steps were identified in formulating the dose-reduction strategy for Rolls-Royce and Associates (RRA): (1) collating the ideas; (2) quantitatively evaluating them on a common basis; (3) prioritizing the ideas in terms of cost benefit, (4) implementation of the highest priority items; (5) monitoring their success; (6) periodically reviewing the strategy. Inherent in producing the dose-reduction strategy has been a comprehensive dose database and the RRA-developed dose management computer code DOMAIN, which allows prediction of dose rates and dose. The database enabled high task dose items to be identified, assisted in evaluating dose benefits, and monitored dose trends once items had been implemented. The DOMAIN code was used both in quantifying some of the project dose benefits and its results, such as dose contours, used in some of the dose-reduction items themselves. In all, over fifty dose-reduction items were evaluated in the strategy process and the items which will give greatest benefit are being implemented. The strategy has been successful in giving renewed impetus and direction to dose-reduction management.

  9. The micro-step motor controller

    International Nuclear Information System (INIS)

    Hong, Kwang Pyo; Lee, Chang Hee; Moon, Myung Kook; Choi, Bung Hun; Choi, Young Hyun; Cheon, Jong Gu

    2004-11-01

    The developed micro-step motor controller can handle 4 axes stepping motor drivers simultaneously and provide high power bipolar driving mechanism with constant current mode. It can be easily controlled by manual key functions and the motor driving status is displayed by the front panel VFD. Due to the development of several kinds of communication and driving protocol, PC can operate even several micro-step motor controllers at once by multi-drop connection

  10. Multi-step contrast sensitivity gauge

    Science.gov (United States)

    Quintana, Enrico C; Thompson, Kyle R; Moore, David G; Heister, Jack D; Poland, Richard W; Ellegood, John P; Hodges, George K; Prindville, James E

    2014-10-14

    An X-ray contrast sensitivity gauge is described herein. The contrast sensitivity gauge comprises a plurality of steps of varying thicknesses. Each step in the gauge includes a plurality of recesses of differing depths, wherein the depths are a function of the thickness of their respective step. An X-ray image of the gauge is analyzed to determine a contrast-to-noise ratio of a detector employed to generate the image.

  11. Step-wise stimulated martensitic transformations

    International Nuclear Information System (INIS)

    Airoldi, G.; Riva, G.

    1991-01-01

    NiTi alloys, widely known both for their shape memory properties and for unusual pseudoelastic behaviour, are now on the forefront attention for step-wise induced memory processes, thermal or stress stimulated. Literature results related to step-wise stimulated martensite (direct transformation) are examined and contrasted with step-wise thermal stimulated parent phase (reverse transformation). Hypothesis are given to explain the key characters of both transformations, a thermodynamic model from first principles being till now lacking

  12. Steps and dislocations in cubic lyotropic crystals

    International Nuclear Information System (INIS)

    Leroy, S; Pieranski, P

    2006-01-01

    It has been shown recently that lyotropic systems are convenient for studies of faceting, growth or anisotropic surface melting of crystals. All these phenomena imply the active contribution of surface steps and bulk dislocations. We show here that steps can be observed in situ and in real time by means of a new method combining hygroscopy with phase contrast. First results raise interesting issues about the consequences of bicontinuous topology on the structure and dynamical behaviour of steps and dislocations

  13. Two-Step Incision for Periarterial Sympathectomy of the Hand

    Directory of Open Access Journals (Sweden)

    Seung Bae Jeon

    2015-11-01

    Full Text Available BackgroundSurgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire.MethodsA total of 40 patients (17 men and 23 women with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS and the Wake Forest University rating scale.ResultsThe total patient score was 8.59 (range, 6-15 in the two-step incision group and 9.62 (range, 7-18 in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034 but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03.ConclusionsCompared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.

  14. Smart Steps to Sustainability 2.0

    Science.gov (United States)

    Smart Steps to Sustainability provides small business owners and managers with practical advice and tools to implementsustainable and environmentally-preferable business practices that go beyond compliance.

  15. Accessory stimulus modulates executive function during stepping task.

    Science.gov (United States)

    Watanabe, Tatsunori; Koyama, Soichiro; Tanabe, Shigeo; Nojima, Ippei

    2015-07-01

    When multiple sensory modalities are simultaneously presented, reaction time can be reduced while interference enlarges. The purpose of this research was to examine the effects of task-irrelevant acoustic accessory stimuli simultaneously presented with visual imperative stimuli on executive function during stepping. Executive functions were assessed by analyzing temporal events and errors in the initial weight transfer of the postural responses prior to a step (anticipatory postural adjustment errors). Eleven healthy young adults stepped forward in response to a visual stimulus. We applied a choice reaction time task and the Simon task, which consisted of congruent and incongruent conditions. Accessory stimuli were randomly presented with the visual stimuli. Compared with trials without accessory stimuli, the anticipatory postural adjustment error rates were higher in trials with accessory stimuli in the incongruent condition and the reaction times were shorter in trials with accessory stimuli in all the task conditions. Analyses after division of trials according to whether anticipatory postural adjustment error occurred or not revealed that the reaction times of trials with anticipatory postural adjustment errors were reduced more than those of trials without anticipatory postural adjustment errors in the incongruent condition. These results suggest that accessory stimuli modulate the initial motor programming of stepping by lowering decision threshold and exclusively under spatial incompatibility facilitate automatic response activation. The present findings advance the knowledge of intersensory judgment processes during stepping and may aid in the development of intervention and evaluation tools for individuals at risk of falls. Copyright © 2015 the American Physiological Society.

  16. STEPS: A NARRATIVE ACCOUNT OF A GABAPENTIN SEEDING TRIAL

    Science.gov (United States)

    Krumholz, Samuel D.; Egilman, David S.; Ross, Joseph S.

    2012-01-01

    Background Seeding trials, clinical studies conducted by pharmaceutical companies for marketing purposes, have rarely been described in detail. Methods We examined all documents relating to the clinical trial Study of Neurontin: Titrate to Effect, Profile of Safety (STEPS) produced during the Neurontin marketing, sales practices and product liability litigation, including company internal and external correspondence, reports, and presentations, as well as depositions elicited in legal proceedings of Harden Manufacturing v. Pfizer and Franklin v. Warner-Lambert, the majority of which were created between 1990 and 2009. Using a systematic search strategy, we identified and reviewed all documents related to the STEPS trial, in order to identify key themes related to the trial’s conduct and determine the extent of marketing involvement in its planning and implementation. Results Documents demonstrated that STEPS was a seeding trial posing as a legitimate scientific study. Documents consistently described the trial itself, not trial results, to be a marketing tactic in the company’s marketing plans. Documents demonstrated that several external sources questioned the validity of the study before execution, and that data quality during the study was often compromised. Furthermore, documents described company analyses examining the impact of participating as a STEPS investigator on rates and dosages of gabapentin prescribing, finding a positive association. None of these findings were reported in two published papers. Conclusions The STEPS trial was a seeding trial, used to promote gabapentin and increase prescribing among investigators, and marketing was extensively involved in its planning and implementation. PMID:21709111

  17. Partnerships – Limited partnerships and limited liability limited partnerships

    OpenAIRE

    Henning, Johan J.

    2000-01-01

    Consideration of the Limited Liability Partnership Act 2000 which introduced a new corporate entity, carrying the designations “partnership” and “limited” which allow members to limit their liability whilst organising themselves internally as a partnership. Article by Professor Johan Henning (Director of the Centre for Corporate Law and Practice, IALS and Dean of the Faculty of Law, University of the Free State, South Africa). Published in Amicus Curiae - Journal of the Institute of Advanced ...

  18. Three-year randomized controlled clinical study of a one step universal adhesive and a two-step self-etch adhesive in Class II resin composite restorations

    DEFF Research Database (Denmark)

    van Dijken, Jan WV; Pallesen, Ulla

    2017-01-01

    Purpose: To evaluate in a randomized clinical evaluation the 3-year clinical durability of a one-step universal adhesive bonding system and compare it intraindividually with a 2-step self-etch adhesive in Class II restorations. Materials and Methods: Each of 57 participants (mean age 58.3 yr......) received at least two, as similar as possible, extended Class II restorations. The cavities in each of the 60 individual pairs of cavities were randomly distributed to the 1-step universal adhesive (All Bond Universal: AU) and the control 2-step self-etch adhesive (Optibond XTR: OX). A low shrinkage resin......) success rates (p>0.05). Annual failure rates were 1.8% and 2.6%, respectively.The main reason for failure was resin composite fracture. Conclusion: Class II resin composite restorations placed with a one-step universal adhesive showed good short time effectiveness....

  19. Knee and ankle range of motion during stepping down in elderly compared to young men

    NARCIS (Netherlands)

    Lark, S.D.; Buckley, J.G.; Jones, D.A.; Sargeant, A.J.

    2004-01-01

    A major factor limiting mobility in elderly subjects is their difficulty with descending steps but the physiological and biomechanical basis of this problem is not well understood. To address this question we have compared the kinematics of stepping down in six elderly male subjects and six weight-

  20. Nucleation on a stepped surface with an Ehrlich–Schwöbel barrier

    International Nuclear Information System (INIS)

    Chromcova, Z; Chvoj, Z; Tringides, M C

    2013-01-01

    During deposition on a stepped surface the growth mode depends on the conditions such as temperature T, deposition rate F and width of the terraces w. In this work we studied the influence of all the above mentioned characteristics using the kinetic Monte Carlo (kMC) technique. We concentrated on the conditions on the terrace at the moment of the first nucleation. The critical density of monomers for nucleation η m decreases with the width of the terrace and the nucleation starts at surprisingly low densities of monomers. We tested several definitions of the critical width for nucleation w c used in various articles in the past and we compared our results with results of the analytical steady-state mean-field model (Ranguelov and Altman 2007 Phys. Rev. B 75 245419). To check how the simplified assumption about the steady-state regime during deposition influences the resulting dependence of w c ≃ (D/F) κ , we set and also solved a time-dependent analytical model. This analytical model as well as kMC predict that w c ≃ (D/F) 1/5 . kMC simulation also shows that the Ehrlich–Schwöbel barrier has only limited influence on the nucleation on the stepped surface at conditions close to the nucleation regime. For all widths of terraces there is a critical value of the Ehrlich–Schwöbel barrier, and only below this critical value does the Ehrlich–Schwöbel barrier affect the final value of the density of nuclei. The results of the kMC are summarized in a semi-empirical analytical formula which describes the dependence of the step-flow growth and nucleation on the terrace width w, diffusion coefficient D and deposition rate F. In our simulations we tested two models of the stepped surface with different thicknesses of the step, both with an Ehrlich–Schwöbel barrier on the edge of the terrace. (paper)