International Nuclear Information System (INIS)
Heintzmann, H.; Novello, M.
1981-01-01
The relative importance of magnetospheric currents and low frequency waves for pulsar braking is assessed and a model is developed which tries to account for the available pulsar timing data under the unifying aspect that all pulsars have equal masses and magnetic moments and are born as rapid rotators. Four epochs of slow-down are distinguished which are dominated by different braking mechanisms. According to the model no direct relationship exists between 'slow-down age' and true age of a pulsar and leads to a pulsar birth-rate of one event per hundred years. (Author) [pt
Energy Technology Data Exchange (ETDEWEB)
Carlvik, I; Pershagen, B
1958-06-15
An infinitely long circular cylinder of radius a is surrounded by an infinite moderator. Both media are non-capturing. The cylinder emits neutrons of age zero with a constant source density of S. We assume that the ratios of the slowing-down powers and of the diffusion constants are independent of the neutron energy. The slowing-down density is calculated for two cases, a) when the slowing-down power of the cylinder medium is very small, and b) when the cylinder medium is identical with the moderator. The ratios of the slowing-down density at the age {tau} and the source density in the two cases are called {psi}{sub V}, and {psi}{sub M} respectively. {psi}{sub V} and {psi}{sub M} are functions of y=a{sup 2}/4{tau}. These two functions ({psi}{sub V} and {psi}{sub M}) are calculated and tabulated for y = 0-0.25.
Slowing down bubbles with sound
Poulain, Cedric; Dangla, Remie; Guinard, Marion
2009-11-01
We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. We render the bubble's oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives rise to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the bubble's drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the bubble's trajectory and consequently to a higher slow down. Our observations may suggest new strategies for bubbly flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.
Neutron slowing-down time in finite water systems
International Nuclear Information System (INIS)
Hirschberg, S.
1981-11-01
The influence of the size of a moderator system on the neutron slowing-down time has been investigated. The experimental part of the study was performed on six cubes of water with side lengths from 8 to 30 cm. Neutrons generated in pulses of about 1 ns width were slowed down from 14 MeV to 1.457 eV. The detection method used was based on registration of gamma radiation from the main capture resonance of indium. The most probable slowing-down times were found to be 778 +- 23 ns and 898 +- 25 ns for the smallest and for the largest cubes, respectively. The corresponding mean slowing-down times were 1205 +- 42 ns and 1311 +- 42 ns. In a separate measurement series the space dependence of the slowing-down time close to the source was studied. These experiments were supplemented by a theoretical calculation which gave an indication of the space dependence of the slowingdown time in finite systems. The experimental results were compared to the slowing-down times obtained from various theoretical approaches and from Monte Carlo calculations. All the methods show a decrease of the slowing-down time with decreasing size of the moderator. This effect was least pronounced in the experimental results, which can be explained by the fact the measurements are spatially dependent. The agreement between the Monte Carlo results and those obtained using the diffusion approximation or the age-diffusion theory is surprisingly good, especially for large systems. The P1 approximation, on the other hand, leads to an overestimation of the effect of the finite size on the slowing-down time. (author)
Tandem queue with server slow-down
Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.
2007-01-01
We study how rare events happen in the standard two-node tandem Jackson queue and in a generalization, the socalled slow-down network, see [2]. In the latter model the service rate of the first server depends on the number of jobs in the second queue: the first server slows down if the amount of
Neutron slowing-down time in matter
Energy Technology Data Exchange (ETDEWEB)
Chabod, Sebastien P., E-mail: sebastien.chabod@lpsc.in2p3.fr [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 38000 Grenoble (France)
2012-03-21
We formulate the neutron slowing-down time through elastic collisions in a homogeneous, non-absorbing, infinite medium. Our approach allows taking into account for the first time the energy dependence of the scattering cross-section as well as the energy and temporal distribution of the source neutron population in the results. Starting from this development, we investigate the specific case of the propagation in matter of a mono-energetic neutron pulse. We then quantify the perturbation on the neutron slowing-down time induced by resonances in the scattering cross-section. We show that a resonance can induce a permanent reduction of the slowing-down time, preceded by two discontinuities: a first one at the resonance peak position and an echo one, appearing later. From this study, we suggest that a temperature increase of the propagating medium in presence of large resonances could modestly accelerate the neutron moderation.
Analysis of the neutron slowing down equation
International Nuclear Information System (INIS)
Sengupta, A.; Karnick, H.
1978-01-01
The infinite series solution of the elementary neutron slowing down equation is studied using the theory of entire functions of exponential type and nonharmonic Fourier series. It is shown from Muntz--Szasz and Paley--Wiener theorems, that the set of exponentials ]exp(ilambda/sub n/u) ]/sup infinity//sub n/=-infinity, where ]lambda/sub n/]/sup infinity//sub n/=-infinity are the roots of the transcendental equation in slowing down theory, is complete and forms a basis in a lethargy interval epsilon. This distinctive role of the maximum lethargy change per collision is due to the Fredholm character of the slowing down operator which need not be quasinilpotent. The discontinuities in the derivatives of the collision density are examined by treating the slowing down equation in its differential-difference form. The solution (Hilbert) space is the union of a countable number of subspaces L 2 (-epsilon/2, epsilon/2) over each of which the exponential functions are complete
Testing algorithms for critical slowing down
Directory of Open Access Journals (Sweden)
Cossu Guido
2018-01-01
Full Text Available We present the preliminary tests on two modifications of the Hybrid Monte Carlo (HMC algorithm. Both algorithms are designed to travel much farther in the Hamiltonian phase space for each trajectory and reduce the autocorrelations among physical observables thus tackling the critical slowing down towards the continuum limit. We present a comparison of costs of the new algorithms with the standard HMC evolution for pure gauge fields, studying the autocorrelation times for various quantities including the topological charge.
Slowing down modernity: A critique : A critique
Vostal , Filip
2017-01-01
International audience; The connection between modernization and social acceleration is now a prominent theme in critical social analysis. Taking a cue from these debates, I explore attempts that aim to 'slow down modernity' by resisting the dynamic tempo of various social processes and experiences. The issue of slowdown now accounts for a largely unquestioned measure, expected to deliver unhasty tempo conditioning good and ethical life, mental well-being and accountable democracy. In princip...
Lead Slowing Down Spectrometer Status Report
International Nuclear Information System (INIS)
Warren, Glen A.; Anderson, Kevin K.; Bonebrake, Eric; Casella, Andrew M.; Danon, Yaron; Devlin, M.; Gavron, Victor A.; Haight, R.C.; Imel, G.R.; Kulisek, Jonathan A.; O'Donnell, J.M.; Weltz, Adam
2012-01-01
This report documents the progress that has been completed in the first half of FY2012 in the MPACT-funded Lead Slowing Down Spectrometer project. Significant progress has been made on the algorithm development. We have an improve understanding of the experimental responses in LSDS for fuel-related material. The calibration of the ultra-depleted uranium foils was completed, but the results are inconsistent from measurement to measurement. Future work includes developing a conceptual model of an LSDS system to assay plutonium in used fuel, improving agreement between simulations and measurement, design of a thorium fission chamber, and evaluation of additional detector techniques.
Energy spectra from coupled electron-photon slowing down
International Nuclear Information System (INIS)
Beck, H.L.
1976-08-01
A coupled electron-photon slowing down calculation for determining electron and photon track length in uniform homogeneous media is described. The method also provides fluxes for uniformly distributed isotropic sources. Source energies ranging from 10 keV to over 10 GeV are allowed and all major interactions are treated. The calculational technique and related cross sections are described in detail and sample calculations are discussed. A listing of the Fortran IV computer code used for the calculations is also included. 4 tables, 7 figures, 16 references
Theory of neutron slowing down in nuclear reactors
Ferziger, Joel H; Dunworth, J V
2013-01-01
The Theory of Neutron Slowing Down in Nuclear Reactors focuses on one facet of nuclear reactor design: the slowing down (or moderation) of neutrons from the high energies with which they are born in fission to the energies at which they are ultimately absorbed. In conjunction with the study of neutron moderation, calculations of reactor criticality are presented. A mathematical description of the slowing-down process is given, with particular emphasis on the problems encountered in the design of thermal reactors. This volume is comprised of four chapters and begins by considering the problems
Experimental studies of heavy-ion slowing down in matter
International Nuclear Information System (INIS)
Geissel, H.; Weick, H.; Scheidenberger, C.; Bimbot, R.; Gardes, D.
2002-08-01
Measurements of heavy-ion slowing down in matter differ in many aspects from experiments with light particles like protons and α-particles. An overview of the special experimental requirements, methods, data analysis and interpretation is presented for heavy-ion stopping powers, energy- and angular-straggling and ranges in the energy domain from keV/u up to GeV/u. Characteristic experimental results are presented and compared with theory and semiempirical predictions. New applications are outlined, which represent a challenge to continuously improve the knowledge of heavy-ion slowing down. (orig.)
Pulsed neutron method for diffusion, slowing down, and reactivity measurements
International Nuclear Information System (INIS)
Sjoestrand, N.G.
1985-01-01
An outline is given on the principles of the pulsed neutron method for the determination of thermal neutron diffusion parameters, for slowing-down time measurements, and for reactivity determinations. The historical development is sketched from the breakthrough in the middle of the nineteen fifties and the usefulness and limitations of the method are discussed. The importance for the present understanding of neutron slowing-down, thermalization and diffusion are point out. Examples are given of its recent use for e.g. absorption cross section measurements and for the study of the properties of heterogeneous systems
Solution of neutron slowing down equation including multiple inelastic scattering
International Nuclear Information System (INIS)
El-Wakil, S.A.; Saad, A.E.
1977-01-01
The present work is devoted the presentation of an analytical method for the calculation of elastically and inelastically slowed down neutrons in an infinite non absorbing homogeneous medium. On the basis of the Central limit theory (CLT) and the integral transform technique the slowing down equation including inelastic scattering in terms of the Green function of elastic scattering is solved. The Green function is decomposed according to the number of collisions. A formula for the flux at any lethargy O (u) after any number of collisions is derived. An equation for the asymptotic flux is also obtained
Investigating the critical slowing down of QCD simulations
International Nuclear Information System (INIS)
Schaefer, Stefan
2009-12-01
Simulations of QCD are known to suffer from serious critical slowing down towards the continuum limit. This is particularly prominent in the topological charge. We investigate the severeness of the problem in the range of lattice spacings used in contemporary simulations and propose a method to give more reliable error estimates. (orig.)
Continuous neutron slowing down theory applied to resonances
International Nuclear Information System (INIS)
Segev, M.
1977-01-01
Neutronic formalisms that discretize the neutron slowing down equations in large numerical intervals currently account for the bulk effect of resonances in a given interval by the narrow resonance approximation (NRA). The NRA reduces the original problem to an efficient numerical formalism through two assumptions: resonance narrowness with respect to the scattering bands in the slowing down equations and resonance narrowness with respect to the numerical intervals. Resonances at low energies are narrow neither with respect to the slowing down ranges nor with respect to the numerical intervals, which are usually of a fixed lethargy width. Thus, there are resonances to which the NRA is not applicable. To stay away from the NRA, the continuous slowing down (CSD) theory of Stacey was invoked. The theory is based on a linear expansion in lethargy of the collision density in integrals of the slowing down equations and had notable success in various problems. Applying CSD theory to the assessment of bulk resonance effects raises the problem of obtaining efficient quadratures for integrals involved in the definition of the so-called ''moderating parameter.'' The problem was solved by two approximations: (a) the integrals were simplified through a rationale, such that the correct integrals were reproduced for very narrow or very wide resonances, and (b) the temperature-broadened resonant line shapes were replaced by nonbroadened line shapes to enable analytical integration. The replacement was made in such a way that the integrated capture and scattering probabilities in each resonance were preserved. The resulting formalism is more accurate than the narrow-resonance formalisms and is equally as efficient
An ultra-fine group slowing down benchmark
International Nuclear Information System (INIS)
Ganapol, B. D.; Maldonado, G. I.; Williams, M. L.
2009-01-01
We suggest a new solution to the neutron slowing down equation in terms of multi-energy panels. Our motivation is to establish a computational benchmark featuring an ultra-fine group calculation, where the number of groups could be on the order of 100,000. While the CENTRM code of the SCALE code package has been shown to adequately treat this many groups, there is always a need for additional verification. The multi panel solution principle is simply to consider the slowing down region as sub regions of panels, with each panel a manageable number of groups, say 100. In this way, we reduce the enormity of dealing with the entire spectrum all at once by considering many smaller problems. We demonstrate the solution in the unresolved U3o8 resonance region. (authors)
Critical slowing down and error analysis in lattice QCD simulations
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Stefan [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Sommer, Rainer; Virotta, Francesco [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2010-09-15
We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)
Critical slowing down and error analysis in lattice QCD simulations
International Nuclear Information System (INIS)
Schaefer, Stefan; Sommer, Rainer; Virotta, Francesco
2010-09-01
We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)
Slowing down of test particles in a plasma (1961)
International Nuclear Information System (INIS)
Belayche, P.; Chavy, P.; Dupoux, M.; Salmon, J.
1961-01-01
Numerical solution of the Fokker-Planck equation applied to the slowing down of tritons in a deuterium plasma. After the equations and the boundary conditions have been written, some attention is paid to the numerical tricks used to run the problem on a high speed electronic computer. The numerical results thus obtained are then analyzed and as far as possible, mathematically explained. (authors) [fr
International Nuclear Information System (INIS)
Kulakovskij, M.Ya.; Savitskij, V.I.
1981-01-01
The errors of multigroup calculating the neutron flux spatial and energy distribution in the fast reactor shield caused by using group and age approximations are considered. It is shown that at small distances from a source the age theory rather well describes the distribution of the slowing-down density. With the distance increase the age approximation leads to underestimating the neutron fluxes, and the error quickly increases at that. At small distances from the source (up to 15 lengths of free path in graphite) the multigroup diffusion approximation describes the distribution of slowing down density quite satisfactorily and at that the results almost do not depend on the number of groups. With the distance increase the multigroup diffusion calculations lead to considerable overestimating of the slowing-down density. The conclusion is drawn that the group approximation proper errors are opposite in sign to the error introduced by the age approximation and to some extent compensate each other
Development of lead slowing down spectrometer for isotopic fissile assay
International Nuclear Information System (INIS)
Lee, Yong Deok; Park, Chang Je; Ahn, Sang Joon; Kim, Ho Dong
2014-01-01
A lead slowing down spectrometer (LSDS) is under development for analysis of isotopic fissile material contents in pyro-processed material, or spent fuel. Many current commercial fissile assay technologies have a limitation in accurate and direct assay of fissile content. However, LSDS is very sensitive in distinguishing fissile fission signals from each isotope. A neutron spectrum analysis was conducted in the spectrometer and the energy resolution was investigated from 0.1eV to 100keV. The spectrum was well shaped in the slowing down energy. The resolution was enough to obtain each fissile from 0.2eV to 1keV. The detector existence in the lead will disturb the source neutron spectrum. It causes a change in resolution and peak amplitude. The intense source neutron production was designed for ∼E12 n's/sec to overcome spent fuel background. The detection sensitivity of U238 and Th232 fission chamber was investigated. The first and second layer detectors increase detection efficiency. Thorium also has a threshold property to detect the fast fission neutrons from fissile fission. However, the detection of Th232 is about 76% of that of U238. A linear detection model was set up over the slowing down neutron energy to obtain each fissile material content. The isotopic fissile assay using LSDS is applicable for the optimum design of spent fuel storage to maximize burnup credit and quality assurance of the recycled nuclear material for safety and economics. LSDS technology will contribute to the transparency and credibility of pyro-process using spent fuel, as internationally demanded.
Topology and slowing down of high energy ion orbits
Energy Technology Data Exchange (ETDEWEB)
Eriksson, L G [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Porcelli, F [Politecnico di Torino, Turin (Italy); Berk, H L [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies
1994-07-01
An analysis of nonstandard guiding centre orbits is presented, which is relevant to MeV ions in a Tokamak. The orbit equation has been simplified from the start, allowing to present an analytic classification of the possible orbits. The topological transitions of the orbits during collisional slowing down are described. In particular, the characteristic equations reveal the existence of a single fixed point in the relevant phase plane, and the presence of a bifurcation curve corresponding to the locus of the pinch orbits. A significant particle inward pinch has been discovered. (authors). 7 figs.
An Exact Solution of The Neutron Slowing Down Equation
Energy Technology Data Exchange (ETDEWEB)
Stefanovic, D [Boris Kidric Vinca Institute of Nuclear Sciences, Vinca, Belgrade (Yugoslavia)
1970-07-01
The slowing down equation for an infinite homogeneous monoatomic medium is solved exactly. The cross sections depend on neutron energy. The solution is given in analytical form within each of the lethargy intervals. This analytical form is the sum of probabilities which are given by the Green functions. The calculated collision density is compared with the one obtained by Bednarz and also with an approximate Wigner formula for the case of a resonance not wider than one collision interval. For the special case of hydrogen, the present solution reduces to Bethe's solution. (author)
Physical condition for the slowing down of cosmic acceleration
Directory of Open Access Journals (Sweden)
Ming-Jian Zhang
2018-04-01
Full Text Available The possible slowing down of cosmic acceleration was widely studied. However, judgment on this effect in different dark energy parameterizations was very ambiguous. Moreover, the reason of generating these uncertainties was still unknown. In the present paper, we analyze the derivative of deceleration parameter q′(z using the Gaussian processes. This model-independent reconstruction suggests that no slowing down of acceleration is presented within 95% C.L. from the Union2.1 and JLA supernova data. However, q′(z from the observational H(z data is a little smaller than zero at 95% C.L., which indicates that future H(z data may have a potential to test this effect. From the evolution of q′(z, we present an interesting constraint on the dark energy and observational data. The physical constraint clearly solves the problem of why some dark energy models cannot produce this effect in previous work. Comparison between the constraint and observational data also shows that most of current data are not in the allowed regions. This implies a reason of why current data cannot convincingly measure this effect.
Physical condition for the slowing down of cosmic acceleration
Zhang, Ming-Jian; Xia, Jun-Qing
2018-04-01
The possible slowing down of cosmic acceleration was widely studied. However, judgment on this effect in different dark energy parameterizations was very ambiguous. Moreover, the reason of generating these uncertainties was still unknown. In the present paper, we analyze the derivative of deceleration parameter q‧ (z) using the Gaussian processes. This model-independent reconstruction suggests that no slowing down of acceleration is presented within 95% C.L. from the Union2.1 and JLA supernova data. However, q‧ (z) from the observational H (z) data is a little smaller than zero at 95% C.L., which indicates that future H (z) data may have a potential to test this effect. From the evolution of q‧ (z), we present an interesting constraint on the dark energy and observational data. The physical constraint clearly solves the problem of why some dark energy models cannot produce this effect in previous work. Comparison between the constraint and observational data also shows that most of current data are not in the allowed regions. This implies a reason of why current data cannot convincingly measure this effect.
On the neutron slowing-down in moderators
Energy Technology Data Exchange (ETDEWEB)
Caldeira, Alexandre D., E-mail: alexdc@ieav.cta.br [Instituto de Estudos Avançados (IEAV), São José dos Campos, SP (Brazil). Divisão de Energia Nuclear
2017-07-01
Neutron slowing-down is a very important subject to be considered in several areas of nuclear energy application, such as thermal nuclear reactors, nuclear medicine, radiological protection, detectors design and so on. Moderator materials are the responsible to perform this task and among the neutron induced cross sections, the elastic scattering cross section is the main nuclear interaction in this case. At thermal neutron energies, the moderator molecular or crystalline structure become important and dependent on the moderator phase, gas, liquid, or solid, its cross sections and, consequently, the angular and energy distributions of the scattered neutron are affected. The procedures used for generating correctly moderators cross sections at thermal neutron energies from evaluated nuclear data files utilizing the NJOY system are addressed. (author)
Slowing down of relativistic heavy ions and new applications
International Nuclear Information System (INIS)
Geissel, H.; Scheidenberger, C.
1997-10-01
New precision experiments using powerful accelerator facilities and high-resolution spectrometers have contributed to a better understanding of the atomic and nuclear interactions of relativistic heavy ions with matter. Experimental results on stopping power and energy-loss straggling of bare heavy projectiles demonstrate large systematic deviations from theories based on first order perturbation. The energy-loss straggling is more than a factor of two enhanced for the heaviest projectiles compared to the relativistic Bohr formula. The interaction of cooled relativistic heavy ions with crystals opens up new fields for basic research and applications, i. e., for the first time resonant coherent excitations of both atomic and nuclear levels can be measured at the first harmonic. The spatial monoisotopic separation of exotic nuclei with in-flight separators and the tumor therapy with heavy ions are new applications based on a precise knowledge of slowing down. (orig.)
Slowing down of alpha particles in ICF DT plasmas
He, Bin; Wang, Zhi-Gang; Wang, Jian-Guo
2018-01-01
With the effects of the projectile recoil and plasma polarization considered, the slowing down of 3.54 MeV alpha particles is studied in inertial confinement fusion DT plasmas within the plasma density range from 1024 to 1026 cm-3 and the temperature range from 100 eV to 200 keV. It includes the rate of the energy change and range of the projectile, and the partition fraction of its energy deposition to the deuteron and triton. The comparison with other models is made and the reason for their difference is explored. It is found that the plasmas will not be heated by the alpha particle in its slowing down the process once the projectile energy becomes close to or less than the temperature of the electron or the deuteron and triton in the plasmas. This leads to less energy deposition to the deuteron and triton than that if the recoil of the projectile is neglected when the temperature is close to or higher than 100 keV. Our model is found to be able to provide relevant, reliable data in the large range of the density and temperature mentioned above, even if the density is around 1026 cm-3 while the deuteron and triton temperature is below 500 eV. Meanwhile, the two important models [Phys. Rev. 126, 1 (1962) and Phys. Rev. E 86, 016406 (2012)] are found not to work in this case. Some unreliable data are found in the last model, which include the range of alpha particles and the electron-ion energy partition fraction when the electron is much hotter than the deuteron and triton in the plasmas.
Lenton, T. M.; Livina, V. N.; Dakos, V.; Van Nes, E. H.; Scheffer, M.
2012-01-01
We address whether robust early warning signals can, in principle, be provided before a climate tipping point is reached, focusing on methods that seek to detect critical slowing down as a precursor of bifurcation. As a test bed, six previously analysed datasets are reconsidered, three palaeoclimate records approaching abrupt transitions at the end of the last ice age and three models of varying complexity forced through a collapse of the Atlantic thermohaline circulation. Approaches based on examining the lag-1 autocorrelation function or on detrended fluctuation analysis are applied together and compared. The effects of aggregating the data, detrending method, sliding window length and filtering bandwidth are examined. Robust indicators of critical slowing down are found prior to the abrupt warming event at the end of the Younger Dryas, but the indicators are less clear prior to the Bølling-Allerød warming, or glacial termination in Antarctica. Early warnings of thermohaline circulation collapse can be masked by inter-annual variability driven by atmospheric dynamics. However, rapidly decaying modes can be successfully filtered out by using a long bandwidth or by aggregating data. The two methods have complementary strengths and weaknesses and we recommend applying them together to improve the robustness of early warnings. PMID:22291229
LEAD SLOWING DOWN SPECTROSCOPY FOR DIRECT Pu MASS MEASUREMENTS
International Nuclear Information System (INIS)
Ressler, Jennifer J.; Smith, Leon E.; Anderson, Kevin K.
2008-01-01
The direct measurement of Pu in previously irradiated fuel assemblies is a recognized need in the international safeguards community. A suitable technology could support more timely and independent material control and accounting (MC and A) measurements at nuclear fuel storage areas, the head-end of reprocessing facilities, and at the product-end of recycled fuel fabrication. Lead slowing down spectroscopy (LSDS) may be a viable solution for directly measuring not only the mass of 239Pu in fuel assemblies, but also the masses of other fissile isotopes such as 235U and 241Pu. To assess the potential viability of LSDS, an LSDS spectrometer was modeled in MCNP5 and 'virtual assays' of nominal PWR assemblies ranging from 0 to 60 GWd/MTU burnup were completed. Signal extraction methods, including the incorporation of nonlinear fitting to account for self-shielding effects in strong resonance regions, are described. Quantitative estimates of Pu uncertainty are given for simplistic and more realistic fuel isotopic inventories calculated using ORIGEN. A discussion of additional signal-perturbing effects that will be addressed in future work, and potential signal extraction approaches that could improve Pu mass uncertainties, are also discussed
Critical slowing down and error analysis in lattice QCD simulations
International Nuclear Information System (INIS)
Virotta, Francesco
2012-01-01
In this work we investigate the critical slowing down of lattice QCD simulations. We perform a preliminary study in the quenched approximation where we find that our estimate of the exponential auto-correlation time scales as τ exp (a)∝a -5 , where a is the lattice spacing. In unquenched simulations with O(a) improved Wilson fermions we do not obtain a scaling law but find results compatible with the behavior that we find in the pure gauge theory. The discussion is supported by a large set of ensembles both in pure gauge and in the theory with two degenerate sea quarks. We have moreover investigated the effect of slow algorithmic modes in the error analysis of the expectation value of typical lattice QCD observables (hadronic matrix elements and masses). In the context of simulations affected by slow modes we propose and test a method to obtain reliable estimates of statistical errors. The method is supposed to help in the typical algorithmic setup of lattice QCD, namely when the total statistics collected is of O(10)τ exp . This is the typical case when simulating close to the continuum limit where the computational costs for producing two independent data points can be extremely large. We finally discuss the scale setting in N f =2 simulations using the Kaon decay constant f K as physical input. The method is explained together with a thorough discussion of the error analysis employed. A description of the publicly available code used for the error analysis is included.
Detector Response to Neutrons Slowed Down in Media Containing Cadmium
Energy Technology Data Exchange (ETDEWEB)
Broda, E.
1943-07-01
This report was written by E. Broda, H. Hereward and L. Kowarski at the Cavendish Laboratory (Cambridge) in September 1943 and is about the detector response to neutrons slowed down in media containing cadmium. The following measurement description and the corresponding results can be found in this report: B, Mn, In, I, Dy and Ir detectors were activated, with and without a Cd shield, near the source in a vessel containing 7 litres of water or solutions of CdSO{sub 4} ranging between 0.1 and 2.8 mols per litre. Numerical data on observed activities are discussed in two different ways and the following conclusions can be drawn: The capture cross-section of dysprosium decreases quicker than 1/v and this discrepancy becomes noticeable well within the limits of the C-group. This imposes obvious limitations on the use of Dy as a detector of thermal neutrons. Cadmium differences of manganese seem to be a reliable 1/v detector for the whole C-group. Indium and iridium show definite signs of an increase of vσ in the upper regions of the C-group. Deviations shown by iodine are due to the imperfections of the technique rather than to a definite departure from the 1/v law. (nowak)
Exact solutions of the neutron slowing down equation
International Nuclear Information System (INIS)
Dawn, T.Y.; Yang, C.N.
1976-01-01
The problem of finding the exact analytic closed-form solution for the neutron slowing down equation in an infinite homogeneous medium is studied in some detail. The existence and unique properties of the solution of this equation for both the time-dependent and the time-independent cases are studied. A direct method is used to determine the solution of the stationary problem. The final result is given in terms of a sum of indefinite multiple integrals by which solutions of some special cases and the Placzek-type oscillation are examined. The same method can be applied to the time-dependent problem with the aid of the Laplace transformation technique, but the inverse transform is, in general, laborious. However, the solutions of two special cases are obtained explicitly. Results are compared with previously reported works in a variety of cases. The time moments for the positive integral n are evaluated, and the conditions for the existence of the negative moments are discussed
Critical slowing down and error analysis in lattice QCD simulations
Energy Technology Data Exchange (ETDEWEB)
Virotta, Francesco
2012-02-21
In this work we investigate the critical slowing down of lattice QCD simulations. We perform a preliminary study in the quenched approximation where we find that our estimate of the exponential auto-correlation time scales as {tau}{sub exp}(a){proportional_to}a{sup -5}, where a is the lattice spacing. In unquenched simulations with O(a) improved Wilson fermions we do not obtain a scaling law but find results compatible with the behavior that we find in the pure gauge theory. The discussion is supported by a large set of ensembles both in pure gauge and in the theory with two degenerate sea quarks. We have moreover investigated the effect of slow algorithmic modes in the error analysis of the expectation value of typical lattice QCD observables (hadronic matrix elements and masses). In the context of simulations affected by slow modes we propose and test a method to obtain reliable estimates of statistical errors. The method is supposed to help in the typical algorithmic setup of lattice QCD, namely when the total statistics collected is of O(10){tau}{sub exp}. This is the typical case when simulating close to the continuum limit where the computational costs for producing two independent data points can be extremely large. We finally discuss the scale setting in N{sub f}=2 simulations using the Kaon decay constant f{sub K} as physical input. The method is explained together with a thorough discussion of the error analysis employed. A description of the publicly available code used for the error analysis is included.
How Accurately Can We Calculate Neutrons Slowing Down In Water ?
International Nuclear Information System (INIS)
Cullen, D E; Blomquist, R; Greene, M; Lent, E; MacFarlane, R; McKinley, S; Plechaty, E; Sublet, J C
2006-01-01
We have compared the results produced by a variety of currently available Monte Carlo neutron transport codes for the relatively simple problem of a fast source of neutrons slowing down and thermalizing in water. Initial comparisons showed rather large differences in the calculated flux; up to 80% differences. By working together we iterated to improve the results by: (1) insuring that all codes were using the same data, (2) improving the models used by the codes, and (3) correcting errors in the codes; no code is perfect. Even after a number of iterations we still found differences, demonstrating that our Monte Carlo and supporting codes are far from perfect; in particularly we found that the often overlooked nuclear data processing codes can be the weakest link in our systems of codes. The results presented here represent the today's state-of-the-art, in the sense that all of the Monte Carlo codes are modern, widely available and used codes. They all use the most up-to-date nuclear data, and the results are very recent, weeks or at most a few months old; these are the results that current users of these codes should expect to obtain from them. As such, the accuracy and limitations of the codes presented here should serve as guidelines to code users in interpreting their results for similar problems. We avoid crystal ball gazing, in the sense that we limit the scope of this report to what is available to code users today, and we avoid predicting future improvements that may or may not actual come to pass. An exception that we make is in presenting results for an improved thermal scattering model currently being testing using advanced versions of NJOY and MCNP that are not currently available to users, but are planned for release in the not too distant future. The other exception is to show comparisons between experimentally measured water cross sections and preliminary ENDF/B-VII thermal scattering law, S(α,β) data; although these data are strictly preliminary
Systematic dependence on the slowing down environment, of nuclear lifetime measurements by DSAM
International Nuclear Information System (INIS)
Toulemonde, M.; Haas, F.
1976-01-01
The meanlife of the 22 Ne 3.34MeV level measured by DSAM (Doppler Shift Attenuation Method) at an average velocity of 0.009 c, shows large fluctuations with different slowing down materials ranging from Li to Pb. These fluctuations are correlated with a linear dependence of the 'apparent' meanlife tau on the electronic slowing down time
Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma
Evans, Eugene S.; Cohen, Samuel A.; Welch, Dale R.
2018-04-01
We report on 3D-3V particle-in-cell simulations of fast-ion energy-loss rates in a cold, weakly-magnetized, weakly-coupled plasma where the electron gyroradius, ρe, is comparable to or less than the Debye length, λDe, and the fast-ion velocity exceeds the electron thermal velocity, a regime in which the electron response may be impeded. These simulations use explicit algorithms, spatially resolve ρe and λDe, and temporally resolve the electron cyclotron and plasma frequencies. For mono-energetic dilute fast ions with isotropic velocity distributions, these scaling studies of the slowing-down time, τs, versus fast-ion charge are in agreement with unmagnetized slowing-down theory; with an applied magnetic field, no consistent anisotropy between τs in the cross-field and field-parallel directions could be resolved. Scaling the fast-ion charge is confirmed as a viable way to reduce the required computational time for each simulation. The implications of these slowing down processes are described for one magnetic-confinement fusion concept, the small, advanced-fuel, field-reversed configuration device.
Slowing down of 100 keV antiprotons in Al foils
Directory of Open Access Journals (Sweden)
K. Nordlund
2018-03-01
Full Text Available Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed. Keywords: Antiprotons, Stopping power, Slowing down, Molecular dynamics
International Nuclear Information System (INIS)
Stefanovic, D.B.
1970-12-01
The objective of this work is to describe the new analytical solution of the neutron slowing down equation for infinite monoatomic media with arbitrary energy dependence of cross section. The solution is obtained by introducing Green slowing down functions instead of starting from slowing down equations directly. The previously used methods for calculation of fission neutron spectra in the reactor cell were numerical. The proposed analytical method was used for calculating the space-energy distribution of fast neutrons and number of neutron reactions in a thermal reactor cell. The role of analytical method in solving the neutron slowing down in reactor physics is to enable understating of the slowing down process and neutron transport. The obtained results could be used as standards for testing the accuracy od approximative and practical methods
Slowing down of 100 keV antiprotons in Al foils
Nordlund, K.
2018-03-01
Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed.
Light slow-down in semiconductor waveguides due to population pulsations
DEFF Research Database (Denmark)
Mørk, Jesper; Kjær, Rasmus; Poel, Mike van der
2005-01-01
This study theoretically analyzes the prospect of inducing light-slow down in a semiconductor waveguide based on coherent population oscillation. Experimental observations of the effect are also presented....
A tandem queue with server slow-down and blocking
van Foreest, N.D.; van Ommeren, Jan C.W.; Mandjes, M.R.H.; Scheinhardt, Willem R.W.
2005-01-01
We consider two variants of a two-station tandem network with blocking. In both variants the first server ceases to work when the queue length at the second station hits a 'blocking threshold.' In addition, in variant 2 the first server decreases its service rate when the second queue exceeds a
A tandem queue with server slow-down and blocking.
van Foreest, N.; van Ommeren, J.C.; Mandjes, M.R.H.; Scheinhardt, W.
2005-01-01
We consider two variants of a two-station tandem network with blocking. In both variants the first server ceases to work when the queue length at the second station hits a 'blocking threshold.' In addition, in variant 2 the first server decreases its service rate when the second queue exceeds a
PN solutions for the slowing-down and the cell calculation problems in plane geometry
International Nuclear Information System (INIS)
Caldeira, Alexandre David
1999-01-01
In this work P N solutions for the slowing-down and cell problems in slab geometry are developed. To highlight the main contributions of this development, one can mention: the new particular solution developed for the P N method applied to the slowing-down problem in the multigroup model, originating a new class of polynomials denominated Chandrasekhar generalized polynomials; the treatment of a specific situation, known as a degeneracy, arising from a particularity in the group constants and the first application of the P N method, for arbitrary N, in criticality calculations at the cell level reported in literature. (author)
7Li neutron-induced elastic scattering cross section measurement using a slowing-down spectrometer
Directory of Open Access Journals (Sweden)
Heusch M.
2010-10-01
Full Text Available A new integral measurement of the 7Li neutron induced elastic scattering cross section was determined in a wide neutron energy range. The measurement was performed on the LPSC-PEREN experimental facility using a heterogeneous graphite-LiF slowing-down time spectrometer coupled with an intense pulsed neutron generator (GENEPI-2. This method allows the measurement of the integral elastic scattering cross section in a slowing-down neutron spectrum. A Bayesian approach coupled to Monte Carlo calculations was applied to extract naturalC, 19F and 7Li elastic scattering cross sections.
Simple and efficient importance sampling scheme for a tandem queue with server slow-down
Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.
2008-01-01
This paper considers importance sampling as a tool for rare-event simulation. The system at hand is a so-called tandem queue with slow-down, which essentially means that the server of the first queue (or: upstream queue) switches to a lower speed when the second queue (downstream queue) exceeds some
Slowing-down of heavy ions in a fusible D-3He mixture
International Nuclear Information System (INIS)
Cocu, Francis; Uzureau, Jose; Lachkar, Jean.
1982-01-01
First experimental results connected with the study of the slowing-down of heavy ions ( 16 O, 63 Cu, 109 Ag) at energies of approximately 1 MeV/A in a fusible mixture of D- 3 He indicate that the higher is the projectile mass the greater is the fusion reaction rate [fr
International Nuclear Information System (INIS)
Melnikov, Dmitriy V; Gracheva, Maria E; Leburton, Jean-Pierre
2012-01-01
We have studied single-stranded DNA translocation through a semiconductor membrane consisting of doped p and n layers of Si forming a p–n-junction. Using Brownian dynamics simulations of the biomolecule in the self-consistent membrane–electrolyte potential obtained from the Poisson–Nernst–Planck model, we show that while polymer length is extended more than when its motion is constricted only by the physical confinement of the nanopore. The biomolecule elongation is particularly dramatic on the n-side of the membrane where the lateral membrane electric field restricts (focuses) the biomolecule motion more than on the p-side. The latter effect makes our membrane a solid-state analog of the α-hemolysin biochannel. The results indicate that the tunable local electric field inside the membrane can effectively control dynamics of a DNA in the channel to either momentarily trap, slow down or allow the biomolecule to translocate at will. (paper)
Slowing down and straggling of protons and heavy ions in matter
International Nuclear Information System (INIS)
Aernsbergen, L.M. van.
1986-01-01
The Doppler Shift Attenuation (DSA) method is widely used to measure lifetimes of nuclear states. However, many of the lifetimes resulting from DSA measurements display large variations which are caused by an insufficient knowledge of slowing down processes of nucleus recoils. The measurement of 'ranges' is an often used method to study these slowing down processes. In this kind of measurement the distributions of implanted ions are determined for example by the method of Rutherford backscattering or from the yield curve of a resonant nuclear reaction. In this thesis, research on energy-loss processes of protons and Si ions in aluminium is presented. The so-called Resonance Shift method has been improved for the measurements on the protons themselves. This method has only been used occasionally before. A new method has been developed, which is called the Transmission Doppler Shift Attenuation (TDSA) method, for the measurement on Si ions. (Auth.)
The Solution of a Velocity-Dependent Slowing-Down Problem Using Case's Eigenfunction Expansion
Energy Technology Data Exchange (ETDEWEB)
Claesson, A
1964-11-15
The slowing-down of neutrons in a hydrogenous moderator is calculated assuming a plane source of monoenergetic neutrons. The scattering is regarded as spherically symmetric, but it is shown that a generalization to anisotropy is possible. The cross-section is assumed to be constant. The virgin neutrons are separated out, and it follows that the distribution of the remaining neutrons can be obtained by using an expansion in the eigenfunctions given by Case for the velocity-independent problem.
Measurement of the Time Dependence of Neutron Slowing-Down and Therma in Heavy Water
Energy Technology Data Exchange (ETDEWEB)
Moeller, E
1966-03-15
The behaviour of neutrons during their slowing-down and thermalization in heavy water has been followed on the time scale by measurements of the time-dependent rate of reaction between the flux and the three spectrum indicators indium, cadmium and gadolinium. The space dependence of the reaction rate curves has also been studied. The time-dependent density at 1.46 eV is well reproduced by a function, given by von Dardel, and a time for the maximum density of 7.1 {+-} 0.3 {mu}s has been obtained for this energy in deuterium gas in agreement with the theoretical value of 7.2 {mu}s. The spatial variation of this time is in accord with the calculations by Claesson. The slowing- down time to 0.2 eV has been found to be 16.3 {+-}2.4 {mu}s. The approach to the equilibrium spectrum takes place with a time constant of 33 {+-}4 {mu}s, and the equilibrium has been established after about 200 {mu}s. Comparison of the measured curves for cadmium and gadolinium with multigroup calculations of the time-dependent flux and reaction rate show the superiority of the scattering models for heavy water of Butler and of Brown and St. John over the mass 2 gas model. The experiment has been supplemented with Monte Carlo calculations of the slowing down time.
Numerical studies of fast ion slowing down rates in cool magnetized plasma using LSP
Evans, Eugene S.; Kolmes, Elijah; Cohen, Samuel A.; Rognlien, Tom; Cohen, Bruce; Meier, Eric; Welch, Dale R.
2016-10-01
In MFE devices, rapid transport of fusion products from the core into the scrape-off layer (SOL) could perform the dual roles of energy and ash removal. The first-orbit trajectories of most fusion products from small field-reversed configuration (FRC) devices will traverse the SOL, allowing those particles to deposit their energy in the SOL and be exhausted along the open field lines. Thus, the fast ion slowing-down time should affect the energy balance of an FRC reactor and its neutron emissions. However, the dynamics of fast ion energy loss processes under the conditions expected in the FRC SOL (with ρe code, to examine the effects of SOL density and background B-field on the slowing-down time of fast ions in a cool plasma. As we use explicit algorithms, these simulations must spatially resolve both ρe and λDe, as well as temporally resolve both Ωe and ωpe, increasing computation time. Scaling studies of the fast ion charge (Z) and background plasma density are in good agreement with unmagnetized slowing down theory. Notably, Z-scaling represents a viable way to dramatically reduce the required CPU time for each simulation. This work was supported, in part, by DOE Contract Number DE-AC02-09CH11466.
Measurement of the Time Dependence of Neutron Slowing-Down and Therma in Heavy Water
International Nuclear Information System (INIS)
Moeller, E.
1966-03-01
The behaviour of neutrons during their slowing-down and thermalization in heavy water has been followed on the time scale by measurements of the time-dependent rate of reaction between the flux and the three spectrum indicators indium, cadmium and gadolinium. The space dependence of the reaction rate curves has also been studied. The time-dependent density at 1.46 eV is well reproduced by a function, given by von Dardel, and a time for the maximum density of 7.1 ± 0.3 μs has been obtained for this energy in deuterium gas in agreement with the theoretical value of 7.2 μs. The spatial variation of this time is in accord with the calculations by Claesson. The slowing- down time to 0.2 eV has been found to be 16.3 ±2.4 μs. The approach to the equilibrium spectrum takes place with a time constant of 33 ±4 μs, and the equilibrium has been established after about 200 μs. Comparison of the measured curves for cadmium and gadolinium with multigroup calculations of the time-dependent flux and reaction rate show the superiority of the scattering models for heavy water of Butler and of Brown and St. John over the mass 2 gas model. The experiment has been supplemented with Monte Carlo calculations of the slowing down time
International Nuclear Information System (INIS)
Williams, M.M.R.
2007-01-01
Description: Prof. M.M..R Williams has now released three of his legacy books for free distribution: 1 - M.M.R. Williams: The Slowing Down and Thermalization of Neutrons, North-Holland Publishing Company - Amsterdam, 582 pages, 1966. Content: Part I - The Thermal Energy Region: 1. Introduction and Historical Review, 2. The Scattering Kernel, 3. Neutron Thermalization in an Infinite Homogeneous Medium, 4. Neutron Thermalization in Finite Media, 5. The Spatial Dependence of the Energy Spectrum, 6. Reactor Cell Calculations, 7. Synthetic Scattering Kernels. Part II - The Slowing Down Region: 8. Scattering Kernels in the Slowing Down Region, 9. Neutron Slowing Down in an Infinite Homogeneous Medium, 10.Neutron Slowing Down and Diffusion. 2 - M.M.R. Williams: Mathematical Methods in Particle Transport Theory, Butterworths, London, 430 pages, 1971. Content: 1 The General Problem of Particle Transport, 2 The Boltzmann Equation for Gas Atoms and Neutrons, 3 Boundary Conditions, 4 Scattering Kernels, 5 Some Basic Problems in Neutron Transport and Rarefied Gas Dynamics, 6 The Integral Form of the Transport Equation in Plane, Spherical and Cylindrical Geometries, 7 Exact Solutions of Model Problems, 8 Eigenvalue Problems in Transport Theory, 9 Collision Probability Methods, 10 Variational Methods, 11 Polynomial Approximations. 3 - M.M.R. Williams: Random Processes in Nuclear Reactors, Pergamon Press Oxford New York Toronto Sydney, 243 pages, 1974. Content: 1. Historical Survey and General Discussion, 2. Introductory Mathematical Treatment, 3. Applications of the General Theory, 4. Practical Applications of the Probability Distribution, 5. The Langevin Technique, 6. Point Model Power Reactor Noise, 7. The Spatial Variation of Reactor Noise, 8. Random Phenomena in Heterogeneous Reactor Systems, 9. Associated Fluctuation Problems, Appendix: Noise Equivalent Sources. Note to the user: Prof. M.M.R Williams owns the copyright of these books and he authorises the OECD/NEA Data Bank
A New Method for Predicting the Penetration and Slowing-Down of Neutrons in Reactor Shields
International Nuclear Information System (INIS)
Hjaerne, L.; Leimdoerfer, M.
1965-05-01
A new approach is presented in the formulation of removal-diffusion theory. The 'removal cross-section' is redefined and the slowing-down between the multigroup diffusion equations is treated with a complete energy transfer matrix rather than in an age theory approximation. The method, based on the new approach contains an adjustable parameter. Examples of neutron spectra and thermal flux penetrations are given in a number of differing shield configurations and the results compare favorably with experiments and Moments Method calculations
Design optimization of radiation shielding structure for lead slowing-down spectrometer system
Kim, Jeong Dong; Ahn, Sangjoon; Lee, Yong Deok; Park, Chang Je
2015-01-01
A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>1012 n/cm2·s) neutron source comprised of a high...
Critical slowing down in driven-dissipative Bose-Hubbard lattices
Vicentini, Filippo; Minganti, Fabrizio; Rota, Riccardo; Orso, Giuliano; Ciuti, Cristiano
2018-01-01
We explore theoretically the dynamical properties of a first-order dissipative phase transition in coherently driven Bose-Hubbard systems, describing, e.g., lattices of coupled nonlinear optical cavities. Via stochastic trajectory calculations based on the truncated Wigner approximation, we investigate the dynamical behavior as a function of system size for one-dimensional (1D) and 2D square lattices in the regime where mean-field theory predicts nonlinear bistability. We show that a critical slowing down emerges for increasing number of sites in 2D square lattices, while it is absent in 1D arrays. We characterize the peculiar properties of the collective phases in the critical region.
A New Method for Predicting the Penetration and Slowing-Down of Neutrons in Reactor Shields
Energy Technology Data Exchange (ETDEWEB)
Hjaerne, L; Leimdoerfer, M
1965-05-15
A new approach is presented in the formulation of removal-diffusion theory. The 'removal cross-section' is redefined and the slowing-down between the multigroup diffusion equations is treated with a complete energy transfer matrix rather than in an age theory approximation. The method, based on the new approach contains an adjustable parameter. Examples of neutron spectra and thermal flux penetrations are given in a number of differing shield configurations and the results compare favorably with experiments and Moments Method calculations.
Measurements with the high flux lead slowing-down spectrometer at LANL
International Nuclear Information System (INIS)
Danon, Y.; Romano, C.; Thompson, J.; Watson, T.; Haight, R.C.; Wender, S.A.; Vieira, D.J.; Bond, E.; Wilhelmy, J.B.; O'Donnell, J.M.; Michaudon, A.; Bredeweg, T.A.; Schurman, T.; Rochman, D.; Granier, T.; Ethvignot, T.; Taieb, J.; Becker, J.A.
2007-01-01
A Lead Slowing-Down Spectrometer (LSDS) was recently installed at LANL [D. Rochman, R.C. Haight, J.M. O'Donnell, A. Michaudon, S.A. Wender, D.J. Vieira, E.M. Bond, T.A. Bredeweg, A. Kronenberg, J.B. Wilhelmy, T. Ethvignot, T. Granier, M. Petit, Y. Danon, Characteristics of a lead slowing-down spectrometer coupled to the LANSCE accelerator, Nucl. Instr. and Meth. A 550 (2005) 397]. The LSDS is comprised of a cube of pure lead 1.2 m on the side, with a spallation pulsed neutron source in its center. The LSDS is driven by 800 MeV protons with a time-averaged current of up to 1 μA, pulse widths of 0.05-0.25 μs and a repetition rate of 20-40 Hz. Spallation neutrons are created by directing the proton beam into an air-cooled tungsten target in the center of the lead cube. The neutrons slow down by scattering interactions with the lead and thus enable measurements of neutron-induced reaction rates as a function of the slowing-down time, which correlates to neutron energy. The advantage of an LSDS as a neutron spectrometer is that the neutron flux is 3-4 orders of magnitude higher than a standard time-of-flight experiment at the equivalent flight path, 5.6 m. The effective energy range is 0.1 eV to 100 keV with a typical energy resolution of 30% from 1 eV to 10 keV. The average neutron flux between 1 and 10 keV is about 1.7 x 10 9 n/cm 2 /s/μA. This high flux makes the LSDS an important tool for neutron-induced cross section measurements of ultra-small samples (nanograms) or of samples with very low cross sections. The LSDS at LANL was initially built in order to measure the fission cross section of the short-lived metastable isotope of U-235, however it can also be used to measure (n, α) and (n, p) reactions. Fission cross section measurements were made with samples of 235 U, 236 U, 238 U and 239 Pu. The smallest sample measured was 10 ng of 239 Pu. Measurement of (n, α) cross section with 760 ng of Li-6 was also demonstrated. Possible future cross section
Slowing-down of non-relativistic ions in a hot dense plasma
International Nuclear Information System (INIS)
Maynard, G.
1982-01-01
The parameter γ (action of the free-electrons of the plasma) was investigated: calculation of the mean value of γ for a great number of monokinetic incident ions and of the dispersion about this mean value, using the random phase approximation; and calculation of the dielectric function. The contribution of the plasma ions to the stopping power was studied and the description of the ion-plasma interaction improved. The slowing-down of an ion at large distance by the bound electrons of an atom was calculated. This study is applied to the ion-plasma interaction in the ion-beam inertial confinement [fr
International Nuclear Information System (INIS)
Datlov, J.; Klima, R.; Kopecky, V.; Musil, J.; Zacek, F.
1977-01-01
An invention is described concerning high-frequency plasma heating and confinement in toroidal magnetic vessels. Microwave energy is applied to the plasma via one or more slowing-down structures exciting low phase velocity waves whose energy may be efficiently absorbed by plasma electrons. The wave momentum transfer results in a toroidal electrical current whose magnetic field together with an external magnetic field ensure plasma confinement. The low-frequency modulation of microwave energy may also be used for heating the ion plasma component. (J.U.)
Geant4-DNA simulation of electron slowing-down spectra in liquid water
Energy Technology Data Exchange (ETDEWEB)
Incerti, S., E-mail: sebastien.incerti@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Univ. Bordeaux, CENBG, UMR 5797, F-33170, Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Kyriakou, I. [Medical Physics Laboratory, University of Ioannina Medical School, 45110 Ioannina (Greece); Tran, H.N. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam)
2017-04-15
This work presents the simulation of monoenergetic electron slowing-down spectra in liquid water by the Geant4-DNA extension of the Geant4 Monte Carlo toolkit (release 10.2p01). These spectra are simulated for several incident energies using the most recent Geant4-DNA physics models, and they are compared to literature data. The influence of Auger electron production is discussed. For the first time, a dedicated Geant4-DNA example allowing such simulations is described and is provided to Geant4 users, allowing further verification of Geant4-DNA track structure simulation capabilities.
International Nuclear Information System (INIS)
Jahshan, S.N.; Wemple, C.A.; Ganapol, B.D.
1993-01-01
A comparison of the numerical solutions of the transport equation describing the steady neutron slowing down in an infinite medium with constant cross sections is made with stochastic solutions obtained from tracking successive neutron histories in the same medium. The transport equation solution is obtained using a numerical Laplace transform inversion algorithm. The basis for the algorithm is an evaluation of the Bromwich integral without analytical continuation. Neither the transport nor the stochastic solution is limited in the number of scattering species allowed. The medium may contain an absorption component as well. (orig.)
Critical slowing down associated with regime shifts in the US housing market
Tan, James Peng Lung; Cheong, Siew Siew Ann
2014-02-01
Complex systems are described by a large number of variables with strong and nonlinear interactions. Such systems frequently undergo regime shifts. Combining insights from bifurcation theory in nonlinear dynamics and the theory of critical transitions in statistical physics, we know that critical slowing down and critical fluctuations occur close to such regime shifts. In this paper, we show how universal precursors expected from such critical transitions can be used to forecast regime shifts in the US housing market. In the housing permit, volume of homes sold and percentage of homes sold for gain data, we detected strong early warning signals associated with a sequence of coupled regime shifts, starting from a Subprime Mortgage Loans transition in 2003-2004 and ending with the Subprime Crisis in 2007-2008. Weaker signals of critical slowing down were also detected in the US housing market data during the 1997-1998 Asian Financial Crisis and the 2000-2001 Technology Bubble Crisis. Backed by various macroeconomic data, we propose a scenario whereby hot money flowing back into the US during the Asian Financial Crisis fueled the Technology Bubble. When the Technology Bubble collapsed in 2000-2001, the hot money then flowed into the US housing market, triggering the Subprime Mortgage Loans transition in 2003-2004 and an ensuing sequence of transitions. We showed how this sequence of couple transitions unfolded in space and in time over the whole of US.
Qsub(N) approximation for slowing-down in fast reactors
International Nuclear Information System (INIS)
Rocca-Volmerange, Brigitte.
1976-05-01
An accurate and simple determination of the neutron energy spectra in fast reactors poses several problems. The slowing-down models (Fermi, Wigner, Goertzel-Greuling...) which are different forms of the approximation with order N=0 may prove inaccurate, in spite of recent improvements. A new method of approximation is presented which turns out to be a method of higher order: the Qsub(N) method. It is characterized by a rapid convergence with respect to the order N, by the use of some global parameters to represent the slowing-down and by the expression of the Boltzmann integral equation in a differential formalism. Numerous test verify that, for the order N=2 or 3, the method gives precision equivalent to that of the multigroup numerical integration for the spectra with greatly reduced calculational effort. Furthermore, since the Qsub(N) expressions are a kind of synthesis method, they allow calculation of the spatial Green's function, or the use of collision probabilities to find the flux. Both possibilities have been introduced into existing reactor codes: EXCALIBUR, TRALOR, RE MINEUR... Some applications to multi-zone media (core, blanket, reflector of Masurca pile and exponential slabs) are presented in the isotropic collision approximation. The case of linearly anisotropic collisions is theoretically resolved [fr
Development for fissile assay in recycled fuel using lead slowing down spectrometer
International Nuclear Information System (INIS)
Lee, Yong Deok; Je Park, C.; Kim, Ho-Dong; Song, Kee Chan
2013-01-01
A future nuclear energy system is under development to turn spent fuels produced by PWRs into fuels for a SFR (Sodium Fast Reactor) through the pyrochemical process. The knowledge of the isotopic fissile content of the new fuel is very important for fuel safety. A lead slowing down spectrometer (LSDS) is under development to analyze the fissile material content (Pu 239 , Pu 241 and U 235 ) of the fuel. The LSDS requires a neutron source, the neutrons will be slowed down through their passage in a lead medium and will finally enter the fuel and will induce fission reactions that will be analysed and the isotopic content of the fuel will be then determined. The issue is that the spent fuel emits intense gamma rays and neutrons by spontaneous fission. The threshold fission detector screens the prompt fast fission neutrons and as a result the LSDS is not influenced by the high level radiation background. The energy resolution of LSDS is good in the range 0.1 eV to 1 keV. It is also the range in which the fission reaction is the most discriminating for the considered fissile isotopes. An electron accelerator has been chosen to produce neutrons with an adequate target through (e - ,γ)(γ,n) reactions
Measurement of the Slowing-Down and Thermalization Time of Neutrons in Water
Energy Technology Data Exchange (ETDEWEB)
Moeller, E [AB Atomenergi, Nykoeping (Sweden); Sjoestrand, N G [Chalmers Univ. of Technology, Goeteborg (Sweden)
1963-11-15
The experimental equipment for the study of the time behaviour of neutrons during slowing-down and thermalization in a moderator by the use of a pulsed van de Graaff accelerator as a neutron source is described. Information on the change with time of the neutron spectrum is obtained from its reaction with spectrum indicators, the reaction rate being observed by the detection of capture gamma rays. The time resolution may be chosen in the range 0.01 to 5 {mu}s. Measurements have been made for water with cadmium, gadolinium and samarium as indicators dissolved in the medium. A slowing- down time to 0.2 eV of 2.7 {+-} 0.4 {mu}s and a total thermalization time of 25 - 30 {mu}s were obtained. From 9 {mu}s after the injection, the results are well described by the assumption of the flux as a Maxwell distribution cooling down to the moderator temperature with a thermalization time constant of 4.1 {+-} 0.4 {mu}s.
Ballooning mode instability due to slowed-down ALPHA -particles and associated transport
International Nuclear Information System (INIS)
Itoh, Sanae; Itoh, Kimitaka; Tuda, Takashi; Tokuda, Shinji.
1982-01-01
The microscopic stability of tokamak plasma, which contains slowed-down alpha-particles and the anomalous fluxes enhanced by the fluctuation, was studied. The local maxwellian distribution with the density inhomogeneity as the equilibrium distribution of electrons, ions and alpha-particles was closen. In the zero-beta limit, two branches of eigenmodes, which are electrostatic, were obtained. The electrostatic ballooning mode became unstable by the grad B drift of particles in the toroidal plasma. It should be noted that there was no critical alpha-particle density and no critical beta-value for the onset of the instability in toroidal plasma even in the presence of the magnetic shear. When the beta-value exceeded the critical beta-value of the MHD ballooning mode, the growth rate approached to that of the MHD mode, and the mode sturcture became very close to that of the MHD mode. The unstable mode in toroidal plasma was the ballooning mode, and was unstable for all plasma parameters. The associated cross-field transport by the ballooning mode is considered. It was found that if the distribution function was assumed to be the birth distribution, the loss rate was very slow and slower than the slowing down time. The effect of alpha-particles on the large scale MHD activity of plasma is discussed. (Kato, T.)
Utilizing the slowing-down-time technique for benchmarking neutron thermalization in graphite
International Nuclear Information System (INIS)
Zhou, T.; Hawari, A. I.; Wehring, B. W.
2007-01-01
Graphite is the moderator/reflector in the Very High Temperature Reactor (VHTR) concept of Generation IV reactors. As a thermal reactor, the prediction of the thermal neutron spectrum in the VHTR is directly dependent on the accuracy of the thermal neutron scattering libraries of graphite. In recent years, work has been on-going to benchmark and validate neutron thermalization in 'reactor grade' graphite. Monte Carlo simulations using the MCNP5 code were used to design a pulsed neutron slowing-down-time experiment and to investigate neutron slowing down and thermalization in graphite at temperatures relevant to VHTR operation. The unique aspect of this experiment is its ability to observe the behavior of neutrons throughout an energy range extending from the source energy to energies below 0.1 eV. In its current form, the experiment is designed and implemented at the Oak Ridge Electron Linear Accelerator (ORELA). Consequently, ORELA neutron pulses are injected into a 70 cm x 70 cm x 70 cm graphite pile. A furnace system that surrounds the pile and is capable of heating the graphite to a centerline temperature of 1200 K has been designed and built. A system based on U-235 fission chambers and Li-6 scintillation detectors surrounds the pile. This system is coupled to multichannel scaling instrumentation and is designed for the detection of leakage neutrons as a function of the slowing-down-time (i.e., time after the pulse). To ensure the accuracy of the experiment, careful assessment was performed of the impact of background noise (due to room return neutrons) and pulse-to-pulse overlap on the measurement. Therefore, the entire setup is surrounded by borated polyethylene shields and the experiment is performed using a source pulse frequency of nearly 130 Hz. As the basis for the benchmark, the calculated time dependent reaction rates in the detectors (using the MCNP code and its associated ENDF-B/VI thermal neutron scattering libraries) are compared to measured
The effect of straggling on the slowing down of neutrons in radiation protection
International Nuclear Information System (INIS)
Mostacci, D.; Molinari, V.; Teodori, F.; Pesic, M.
1999-01-01
All those techniques developed to describe neutron transport that rely on the flux isotropy conditions prevailing within the reactor core can be of no help in the study of neutron beams. Two main problems must be solved in investigating beams: determining the relevant cross-sections and solving the transport equation. Often in addressing neutron radiation protection problems, the available cross-section data are extremely detailed whereas the transport equations used are rather unrefined, making wide use of the continuous slowing down approximation to calculate stopping powers (e.g., Bethe's expressions). In this paper a simple approach to calculating stopping power and range is presented, that takes into account the effect of neutron energy straggling. Comparison with MCNP results is also presented. (author)
Measurement of fission cross section with pure Am-243 sample using lead slowing-down spectrometer
Energy Technology Data Exchange (ETDEWEB)
Kobayashi, Katsuhei; Yamamoto, Shuji; Kai, T.; Fujita, Yoshiaki; Yamamoto, Hideki; Kimura, Itsuro [Kyoto Univ. (Japan); Shinohara, Nobuo
1997-03-01
By making use of back-to-back type double fission chambers and a lead slowing-down spectrometer coupled to an electron linear accelerator, the fission cross section for the {sup 243}Am(n,f) reaction has been measured relative to that for the {sup 235}U(n,f) reaction in the energy range from 0.1 eV to 10 keV. The measured result was compared with the evaluated nuclear data appeared in ENDF/B-VI and JENDL-3.2, whose evaluated data were broadened by the energy resolution function of the spectrometer. General agreement was seen between the evaluated data and the measurement except that the ENDF/B-VI data were lower in the range from 15 to 60 eV and that the JENDL-3.2 data seemed to be lower above 100 eV. (author)
International Nuclear Information System (INIS)
Prinja, A.K.
1997-01-01
A nonlinear discretization scheme in space and energy, based on the recently developed exponential discontinuous method, is applied to continuous slowing down dominated electron transport (i.e., in the absence of scattering.) Numerical results for dose and charge deposition are obtained and compared against results from the ONELD and ONEBFP codes, and against exact results from an adjoint Monte Carlo code. It is found that although the exponential discontinuous scheme yields strictly positive and monotonic solutions, the dose profile is considerably straggled when compared to results from the linear codes. On the other hand, the linear schemes produce negative results which, furthermore, do not damp effectively in some cases. A general conclusion is that while yielding strictly positive solutions, the exponential discontinuous method does not show the crude cell accuracy for charged particle transport as was apparent for neutral particle transport problems
Episodic memory deficits slow down the dynamics of cognitive procedural learning in normal ageing
Beaunieux, Hélène; Hubert, Valérie; Pitel, Anne Lise; Desgranges, Béatrice; Eustache, Francis
2009-01-01
Cognitive procedural learning is characterized by three phases, each involving distinct processes. Considering the implication of the episodic memory in the first cognitive stage, the impairment of this memory system might be responsible for a slowing down of the cognitive procedural learning dynamics in the course of aging. Performances of massed cognitive procedural learning were evaluated in older and younger participants using the Tower of Toronto task. Nonverbal intelligence and psychomotor abilities were used to analyze procedural dynamics, while episodic memory and working memory were assessed to measure their respective contributions to learning strategies. This experiment showed that older participants did not spontaneously invoke episodic memory and presented a slowdown in the cognitive procedural learning associated with a late involvement of working memory. These findings suggest that the slowdown in the cognitive procedural learning may be linked with the implementation of different learning strategies less involving episodic memory in older subjects. PMID:18654928
Critical slowing down of spin fluctuations in BiFeO3
International Nuclear Information System (INIS)
Scott, J F; Singh, M K; Katiyar, R S
2008-01-01
In earlier work we reported the discovery of phase transitions in BiFeO 3 evidenced by divergences in the magnon light-scattering cross-sections at 140 and 201 K (Singh et al 2008 J. Phys.: Condens. Matter 20 252203) and fitted these intensity data to critical exponents α = 0.06 and α' = 0.10 (Scott et al 2008 J. Phys.: Condens. Matter 20 322203), under the assumption that the transitions are strongly magnetoelastic (Redfern et al 2008 at press) and couple to strain divergences through the Pippard relationship (Pippard 1956 Phil. Mag. 1 473). In the present paper we extend those criticality studies to examine the magnon linewidths, which exhibit critical slowing down (and hence linewidth narrowing) of spin fluctuations. The linewidth data near the two transitions are qualitatively different and we cannot reliably extract a critical exponent ν, although the mean field value ν = 1/2 gives a good fit near the lower transition.
ACTIV, Sandwich Detector Activity from In-Pile Slowing-Down Spectra Experiment
International Nuclear Information System (INIS)
Bozzi, L. and others
1978-01-01
1 - Nature of physical problem solved: Calculates the activities of a sandwich detector, to be used for in-pile measurements in slowing-down spectra below a few keV. The effect of scattering with energy degradation in the filter and in the detectors has been included to a first approximation. 2 - Method of solution: An iterative procedure is used: the calculation starts with a flux guess in which one assumes that each measured reactivity difference depends on the principal resonance only. The secondary resonance contribution is computed through the iterative process. For self-shielded cross-section calculations the model of Pearlstein and Weinstock (ref. 3) is used. The neutron spectrum can optionally be constant or 1/E inside each finite energy group relative to the resonance considered. 3 - Restrictions on the complexity of the problem: Maximum number of energy groups : 60
ROLAIDS-CPM, 1-D Slowing-Down by Collision Problems Method
International Nuclear Information System (INIS)
De Kruijf, W.J.M.
2002-01-01
1 - Description of program or function: ROLAIDS-CPM is based on the AMPX-module ROLAIDS (PSR-315). CPM stands for Collision Probability Method. ROLAIDS is a one-dimensional slowing-down code which uses the interface currents method. ROLAIDS-CPM does not need the assumption of cosine currents at the interface of the zones. Extensions: collision probability method for slab and cylinder geometry; different temperatures for a nuclide can be used; flat lethargy source can be modelled. 2 - Method of solution: Collision probabilities in cylindrical geometry are calculated according to the Carlvik Method. This means that a Gauss integration is used. 3 - Restrictions on the complexity of the problem: The maximum number of zones is 30 for the collision probability method
Experimental and theoretical study of heavy ion slowing down in solid targets
International Nuclear Information System (INIS)
Mehana, A.
1993-06-01
Heavy ion energy losses in C, Al, Cu, Ag, Ta and Au solid targets have been measured at high energy (0.2 to 5 MeV/u), using the backward secondary ion technique, and at low energy (0.1 to 0.25 MeV/u) for the C, N and O ions, using the particle backscatter method. A brief review of the various matter-induced charged particle slowing down theories, and especially the Lindhard dielectric theory, is first presented. Then, the various models for the evaluation of the effective charge and of the high order correction, are discussed and compared. Experimental techniques and data processing methods are described, and the experimental results are compared to calculations derived from the dielectric theory. In particular, the effective charges and the high order corrections (Barkas-Bloch) are examined and compared to the models for the determination of the z 3 and z 4 terms for heavy ions
Evaluation of Shielding Wall Optimization in Lead Slowing Down Spectrometer System
Energy Technology Data Exchange (ETDEWEB)
Jeon, Ju Young; Kim, Jeong Dong; Lee, Yong Deok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
A Lead Slowing Down Spectrometer (LSDS) system is nondestructive technology for analyzing isotope fissile content in spent fuel and pyro processed material, in real time and directly. The high intensity neutron and gamma ray were generated from a nuclear material (Pyro, Spent nuclear fuel), electron beam-target reaction and fission of fissile material. Therefore, shielding analysis of LSDS system should be carried out. In this study, Borax, B{sub 4}C, Li{sub 2}Co{sub 3}, Resin were chosen for shielding analysis. The radiation dose limit (<0.1 μSv/hr) was adopted conservatively at the outer wall surface. The covering could be able to reduce the concrete wall thickness from 5cm to 15cm. The optimized shielding walls evaluation will be used as an important data for future real LSDS facility design and shielding door assessment.
Analysis of spent fuel assay with a lead slowing down spectrometer
International Nuclear Information System (INIS)
Gavron, A.; Smith, L. Eric; Ressler, Jennifer J.
2009-01-01
Assay of fissile materials in spent fuel that are produced or depleted during the operation of a reactor, is of paramount importance to nuclear materials accounting, verification of the reactor operation history, as well as for criticality considerations for storage. In order to prevent future proliferation following the spread of nuclear energy, we must develop accurate methods to assay large quantities of nuclear fuels. We analyze the potential of using a Lead Slowing Down Spectrometer for assaying spent fuel. We conclude that it possible to design a system that will provide around 1% statistical precision in the determination of the 239 Pu, 241 Pu and 235 U concentrations in a PWR spent-fuel assembly, for intermediate-to-high burnup levels, using commercial neutron sources, and a system of 238 U threshold fission detectors. Pending further analysis of systematic errors, it is possible that missing pins can be detected, as can asymmetry in the fuel bundle. (author)
Slowing down tail enhanced, neoclassical and classical alpha particle fluxes in tokamak reactors
International Nuclear Information System (INIS)
Catto, P.J.; Tessarotto, M.
1988-01-01
The classical and neoclassical particle and energy fluxes associated with a slowing down tail, alpha particle distribution function are evaluated for arbitrary aspect ratio ε -1 , cross section, and poloidal magnetic field. The retention of both electron and ion drag and pitch angle scattering by the background ions results in a large diffusive neoclassical heat flux in the plasma core. This flux remains substantial at larger radii only if the characteristic speed associated with pitch angle scattering, v/sub b/, is close enough to the alpha birth speed v 0 so that ε(v 0 /v/sub b/) 3 remains less than some order unity critical value which is not determined by the methods herein. The enhanced neoclassical losses would only have a serious impact on ignition if the critical value of ε(v 0 /v/sub b/) 3 is found to be somewhat larger than unity
Fission cross section measurement of Am-242m using lead slowing-down spectrometer
Energy Technology Data Exchange (ETDEWEB)
Kai, Tetsuya; Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Kimura, Itsuro; Ohkawachi, Yasushi; Wakabayashi, Toshio
1998-03-01
By making use of double fission chamber and lead slowing-down spectrometer coupled to an electron linear accelerator, fission cross section for the {sup 242m}Am(n,f) reaction has been measured relative to that for the {sup 235}U(n,f) reaction in the energy range from 0.1 eV to 10 keV. The measured result was compared with the evaluated nuclear data appeared in ENDF/B-VI and JENDL-3.2, of which evaluated data were broadened by the energy resolution function of the spectrometer. Although the JENDL-3.2 data seem to be a little smaller than the present measurement, good agreement can be seen in the general shape and the absolute values. The ENDF/B-VI data are larger more than 50 % than the present values above 3 eV. (author)
Study of the neutron slowing-down in graphite; Etude du ralentissement des neutrons dans le graphite
Energy Technology Data Exchange (ETDEWEB)
Martelly, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Duggal, V P [Commission a l' Energie atomique indienne (India)
1955-07-01
Study of the slowing-down age of neutrons in graphite. In the aim to eliminate the effect of resonance neutrons on the detector, neutrons captured by cadmium are studied with a classic method consisting of calculating the difference between the activity measured with and without screens. This method is described and screening properties of cadmium and gadolinium are compared. The experimental parameters and detectors details are described. The radioactive source is Ra-{alpha}-Be. The experimental results are given and the experimental distribution is compared with theoretical formula. In a second part, the spatial distribution of resonance neutrons in indium is discussed. Finally, the neutron slowing-down between the indium resonance and the thermal equilibrium is discussed as well as the research for the effective value of slowing-down age. The slowing-down age definition is given before calculating its effective value. It compared the slowing-down law with the experiment and the Gurney theory. (M.P.)
Lead Slowing-Down Spectrometry for Spent Fuel Assay: FY11 Status Report
International Nuclear Information System (INIS)
Warren, Glen A.; Casella, Andrew M.; Haight, R.C.; Anderson, Kevin K.; Danon, Yaron; Hatchett, D.; Becker, Bjorn; Devlin, M.; Imel, G.R.; Beller, D.; Gavron, A.; Kulisek, Jonathan A.; Bowyer, Sonya M.; Gesh, Christopher J.; O'Donnell, J.M.
2011-01-01
Executive Summary Developing a method for the accurate, direct, and independent assay of the fissile isotopes in bulk materials (such as used fuel) from next-generation domestic nuclear fuel cycles is a goal of the Office of Nuclear Energy, Fuel Cycle R and D, Material Protection and Control Technology (MPACT) Campaign. To meet this goal, MPACT supports a multi-institutional collaboration to study the feasibility of Lead Slowing Down Spectroscopy (LSDS). This technique is an active nondestructive assay method that has the potential to provide independent, direct measurement of Pu and U isotopic masses in used fuel with an uncertainty considerably lower than the approximately 10% typical of today's confirmatory assay methods. This document is a progress report for FY2011 collaboration activities. Progress made by the collaboration in FY2011 continues to indicate the promise of LSDS techniques applied to used fuel. PNNL developed an empirical model based on calibration of the LSDS to responses generated from well-characterized used fuel. The empirical model demonstrated the potential for the direct and independent assay of the sum of the masses of 239Pu and 241Pu to within approximately 3% over a wide used fuel parameter space. Similar results were obtained using a perturbation approach developed by LANL. Benchmark measurements have been successfully conducted at LANL and at RPI using their respective LSDS instruments. The ISU and UNLV collaborative effort is focused on the fabrication and testing of prototype fission chambers lined with ultra-depleted 238U and 232Th, and uranium deposition on a stainless steel disc using spiked U3O8 from room temperature ionic liquid was successful, with improving thickness obtained. In FY2012, the collaboration plans a broad array of activities. PNNL will focus on optimizing its empirical model and minimizing its reliance on calibration data, as well continuing efforts on developing an analytical model. Additional measurements are
Spectral history correction of microscopic cross sections for the PBR using the slowing down balance
International Nuclear Information System (INIS)
Hudson, N.; Rahnema, F.; Ougouag, A. M.; Gougar, H. D.
2006-01-01
A method has been formulated to account for depletion effects on microscopic cross sections within a Pebble Bed Reactor (PBR) spectral zone without resorting to calls to the spectrum (cross section generation) code or relying upon table interpolation between data at different values of burnup. In this method, infinite medium microscopic cross sections, fine group fission spectra, and modulation factors are pre-computed at selected isotopic states. This fine group information is used with the local spectral zone nuclide densities to generate new cross sections for each spectral zone. The local spectrum used to generate these microscopic cross sections is estimated through the solution to the cell-homogenized, infinite medium slowing down balance equation during the flux calculation. This technique is known as Spectral History Correction (SHC), and it is formulated to specifically account for burnup within a spectral zone. It was found that the SHC technique accurately calculates local broad group microscopic cross sections with local burnup information. Good agreement is obtained with cross sections generated directly by the cross section generator. Encouraging results include improvement in the converged fuel cycle eigenvalue, the power peaking factor, and the flux. It was also found that the method compared favorably to the benchmark problem in terms of the computational speed. (authors)
Oligotrophication and Metabolic Slowing-Down of a NW Mediterranean Coastal Ecosystem
Agusti, Susana
2017-12-22
Increased oligotrophication is expected for oligotrophic areas as a consequence of ocean warming, which reduces diffusive vertical nutrient supply due to strengthened stratification. Evidence of ocean oligotrophication has been, thus far, reported for the open ocean. Here we reported oligotrophication and associated changes in plankton community metabolism with warming in a pristine, oligotrophic Mediterranean coastal area (Cap Salines, Mallorca Island, Spain) during a 10 years time series. As a temperate area, there were seasonal patterns associated to changes in the broad temperature range (12.0–28.4°C), with a primary phytoplankton bloom in late winter and a secondary one in the fall. Community respiration (R) rates peaked during summers and showed higher rates relative to gross primary production (GPP) with a prevalence of heterotrophic metabolism (2/3\\'s of net community production (NCP) estimates). Chlorophyll a concentration significantly decreased with increasing water temperature in the coastal site at a rate of 0.014 ± 0.003 μg Chla L−1 °C−1 (P < 0.0001). The study revealed a significant decrease with time in Chlorophyll a concentration and nutrients concentration, indicating oligotrophication during the last decade. Community productivity consistently decreased with time as both GPP and R showed a significant decline. Warming of the Mediterranean Sea is expected to increase plankton metabolic rates, but the results indicated that the associated oligotrophication must lead to a slowing down of the community metabolism.
Neutron slowing down and transport in a medium of constant cross section. I. Spatial moments
International Nuclear Information System (INIS)
Cacuci, D.G.; Goldstein, H.
1977-01-01
Some aspects of the problem of neutron slowing down and transport have been investigated in an infinite medium consisting of a single nuclide scattering elastically and isotropically without absorption and with energy-independent cross sections. The method of singular eigenfunctions has been applied to the Boltzmann equation governing the Laplace transform (with respect to the lethargy variable) of the neutron flux. Formulas have been obtained for the lethargy dependent spatial moments of the scalar flux applicable in the limit of large lethargy. In deriving these formulas, use has been made of the well-known connection between the spatial moments of the Laplace-transformed scalar flux and the moments of the flux in the ''eigenvalue space.'' The calculations have been greatly aided by the construction of a closed general expression for these ''eigenvalue space'' moments. Extensive use has also been made of the methods of combinatorial analysis and of computer evaluation, via FORMAC, of complicated sequences of manipulations. It has been possible to obtain for materials of any atomic weight explicit corrections to the age theory formulas for the spatial moments M/sub 2n/(u), of the scalar flux, valid through terms of order of u -5 . Higher order correction terms could be obtained at the expense of additional computer time. The evaluation of the coefficients of the powers of n, as explicit functions of the nuclear mass, represent the end product of this investigation
Third generation of lead slowing-down spectrometers: First results and prospects
International Nuclear Information System (INIS)
Alexeev, A.A.; Belousov, Yu.V.; Bergman, A.A.; Volkov, A.N.; Goncharenko, O.N.; Grachev, M.N.; Kazarnovsky, M.V.; Matushkov, V.L.; Mostovoy, V.I.; Novikov, A.V.; Novoselov, S.A.; Ryabov, Yu.V.; Stavissky, Yu.Ya.; Gledenov, Yu.M.; Parzhitski, S.S.; Popov, Yu.P.
1999-01-01
At the same neutron-source intensity S, lead slowing-down spectrometers (LSDS) for neutrons possess luminosity 10 3 -10 4 times as great as that of time-of-flight spectrometers with the same energy resolution ΔE/E(bar sign) (for the former, ΔE/E(bar sign)≅35-45% at a mean energy E(bar sign) less than 50 keV). In combination with high-current proton accelerators, third-generation LSDSs can operate at S values exceeding those acceptable for second-generation LSDSs coupled to electron accelerators by a factor of 10 2 to 10 3 . At the Institute for Nuclear Research (Russian Academy of Sciences, Moscow), the first third-generation LSDS facility called PITON (about 15 tons of lead) has been operating successfully and a large LSDS (more than 100 tons of lead) is now under construction. The results of the first experiments at the PITON facility are presented, and the experimental programs for both facilities is outlined
International Nuclear Information System (INIS)
Kulisek, Jonathan A.; Anderson, Kevin K.; Casella, Andrew M.; Gesh, Christopher J.; Warren, Glen A.
2013-01-01
This study investigates the use of a Lead Slowing-Down Spectrometer (LSDS) for the direct and independent measurement of fissile isotopes in light-water nuclear reactor fuel assemblies. The current study applies MCNPX, a Monte Carlo radiation transport code, to simulate the measurement of the assay of the used nuclear fuel assemblies in the LSDS. An empirical model has been developed based on the calibration of the LSDS to responses generated from the simulated assay of six well-characterized fuel assemblies. The effects of self-shielding are taken into account by using empirical basis vectors calculated from the singular value decomposition (SVD) of a matrix containing the self-shielding functions from the assay of assemblies in the calibration set. The performance of the empirical algorithm was tested on version 1 of the Next-Generation Safeguards Initiative (NGSI) used fuel library consisting of 64 assemblies, as well as a set of 27 diversion assemblies, both of which were developed by Los Alamos National Laboratory. The potential for direct and independent assay of the sum of the masses of Pu-239 and Pu-241 to within 2%, on average, has been demonstrated
Timing of the Crab pulsar III. The slowing down and the nature of the random process
International Nuclear Information System (INIS)
Groth, E.J.
1975-01-01
The Crab pulsar arrival times are analyzed. The data are found to be consistent with a smooth slowing down with a braking index of 2.515+-0.005. Superposed on the smooth slowdown is a random process which has the same second moments as a random walk in the frequency. The strength of the random process is R 2 >=0.53 (+0.24, -0.12) x10 -22 Hz 2 s -1 , where R is the mean rate of steps and 2 > is the second moment of the step amplitude distribution. Neither the braking index nor the strength of the random process shows evidence of statistically significant time variations, although small fluctuations in the braking index and rather large fluctuations in the noise strength cannot be ruled out. There is a possibility that the random process contains a small component with the same second moments as a random walk in the phase. If so, a time scale of 3.5 days is indicated
Oligotrophication and Metabolic Slowing-Down of a NW Mediterranean Coastal Ecosystem
Directory of Open Access Journals (Sweden)
Susana Agusti
2017-12-01
Full Text Available Increased oligotrophication is expected for oligotrophic areas as a consequence of ocean warming, which reduces diffusive vertical nutrient supply due to strengthened stratification. Evidence of ocean oligotrophication has been, thus far, reported for the open ocean. Here we reported oligotrophication and associated changes in plankton community metabolism with warming in a pristine, oligotrophic Mediterranean coastal area (Cap Salines, Mallorca Island, Spain during a 10 years time series. As a temperate area, there were seasonal patterns associated to changes in the broad temperature range (12.0–28.4°C, with a primary phytoplankton bloom in late winter and a secondary one in the fall. Community respiration (R rates peaked during summers and showed higher rates relative to gross primary production (GPP with a prevalence of heterotrophic metabolism (2/3's of net community production (NCP estimates. Chlorophyll a concentration significantly decreased with increasing water temperature in the coastal site at a rate of 0.014 ± 0.003 μg Chla L−1 °C−1 (P < 0.0001. The study revealed a significant decrease with time in Chlorophyll a concentration and nutrients concentration, indicating oligotrophication during the last decade. Community productivity consistently decreased with time as both GPP and R showed a significant decline. Warming of the Mediterranean Sea is expected to increase plankton metabolic rates, but the results indicated that the associated oligotrophication must lead to a slowing down of the community metabolism.
ADVANCEMENTS IN TIME-SPECTRA ANALYSIS METHODS FOR LEAD SLOWING-DOWN SPECTROSCOPY
International Nuclear Information System (INIS)
Smith, Leon E.; Anderson, Kevin K.; Gesh, Christopher J.; Shaver, Mark W.
2010-01-01
Direct measurement of Pu in spent nuclear fuel remains a key challenge for safeguarding nuclear fuel cycles of today and tomorrow. Lead slowing-down spectroscopy (LSDS) is an active nondestructive assay method that has the potential to provide independent, direct measurement of Pu and U isotopic mass with an uncertainty lower than the approximately 10 percent typical of today's confirmatory assay methods. Pacific Northwest National Laboratory's (PNNL) previous work to assess the viability of LSDS for the assay of pressurized water reactor (PWR) assemblies indicated that the method could provide direct assay of Pu-239 and U-235 (and possibly Pu-240 and Pu-241) with uncertainties less than a few percent, assuming suitably efficient instrumentation, an intense pulsed neutron source, and improvements in the time-spectra analysis methods used to extract isotopic information from a complex LSDS signal. This previous simulation-based evaluation used relatively simple PWR fuel assembly definitions (e.g. constant burnup across the assembly) and a constant initial enrichment and cooling time. The time-spectra analysis method was founded on a preliminary analytical model of self-shielding intended to correct for assay-signal nonlinearities introduced by attenuation of the interrogating neutron flux within the assembly.
International Nuclear Information System (INIS)
Bouhelal, O.K.A.
1990-01-01
The exact determination of the effective multigroup cross sections imposes the numerical solution of the slowing down equation on a very fine energy mesh. Given the complexity of these calculations, different approximation methods have been developed but without a satisfactory treatment of the slowing-down effect. The usual methods are essentially based on interpolations using precalculated tables. The models that use the probability tables allow to reduce the amount of data and the computational effort. A variety of methods proposed by Soviets, then by Americans, and finally the French method, based on the ''moments of a probability distribution'' are incontestably valid within the framework of the statistical hypothesis. This stipulates that the collision densities do not depend on cross section and there is no ambiguity in the effective cross section calculation. The objective of our work is to show that the non statistical phenomena, such as the slowing-down effect which is taken into account, can be described by probability tables which are able to represent the neutronic values and collision densities. The formalism involved in the statistical hypothesis, is based on the Gauss quadrature of the cross sections moments. In the non-statistical hypothesis we introduce the crossed probability tables using the quadratures of double integrals of cross sections, comments. Moreover, a mathematical formalism allowing to establish a relationship between the crossed probability tables and the collision densities was developed. This method was applied on uranium-238 in the range of resolved resonances where the slowing down effect is significant. Validity of the method and the analysis of the obtained results are studied through a reference calculation based on a solution of a discretized slowing down equation using a very fine mesh in which each microgroup can be correctly defined via the statistical probability tables. 42 figs., 32 tabs., 49 refs. (author)
Nuclear lifetimes and the slowing down of heavy ions in solids
International Nuclear Information System (INIS)
Scherpenzeel, D.E.C.
1981-01-01
Nuclear lifetime measurements by means of the Doppler Shift Attenuation (DSA) method at low recoil velocities (β approximately less than 0.01) are notoriously difficult due to the observed strong dependence of the extracted lifetimes on the slowing-down material at low initial velocities. This is mainly caused by the lack of reliable stopping power data for these velocities and the absence of an adequate theory to compensate for that. This problem of the determination of the correct mean life for the lowest Jsup(π) = 4 + state of 22 Ne is solved by measurements with the coincident high-velocity DSA method. Excited nuclei of high initial velocity [β(0) approximately 0.05] are generated by the bombardment of light targets, such as 1 H, 2 H, 3 H and 4 He, with beams of heavy ions. The combination of high initial velocity and coincidence restriction offers many advantages over the conventional techniques. The coincident high-velocity DSA method is also used to determine mean lives of low-lying excited states of the silicon isotopes 28 29 30 Si. The observed Doppler patterns are analyzed with experimental stopping powers and the resulting mean lives range from about 25 fs to 4 ps. The mean lives of the first excited state of 18 O and some low-lying levels of 35 S are determined from Doppler patterns analyzed with experimental stopping powers. The present stopping results for O, Si and S ions in Mg are also analyzed in terms of the effective charge concept. It is concluded that at the present level of accuracy of about 5 % the obtained results are consistent with this concept. (Auth.)
Design optimization of radiation shielding structure for lead slowing-down spectrometer system
International Nuclear Information System (INIS)
Kim, Jeong Dong; Ahn, Sang Joon; Lee, Yong Deok; Park, Chang Je
2015-01-01
A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>101 2n /cm 2 ·s) neutron source comprised of a high-energy (30 MeV)/high-current (∼2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h), a few shielding materials [high-density polyethylene (HDPE)–Borax, B 4 C, and Li 2 CO 3 ] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near future.
Confinement of ripple-trapped slowing-down ions by a radial electric field
International Nuclear Information System (INIS)
Herrmann, W.
1998-03-01
Weakly collisional ions trapped in the toroidal field ripples at the outer plasma edge can be prevented to escape the plasma due to grad B-drift by a counteracting radial electric field. This leads to an increase in the density of ripple-trapped ions, which can be monitored by the analysis of charge exchange neutrals. The minimum radial electric field E r necessary to confine ions with energy E and charge q (q=-1: charge of the electron) is E r = -E/(q * R), where R is the major radius at the measuring point. Slowing-down ions from neutral injection are usually in the right energy range to be sufficiently collisionless in the plasma edge and show the confinement by radial electric fields in the range of tens of kV/m. The density of banana ions is almost unaffected by the radial electric field. Neither in L/H- nor in H/L-transitions does the density of ripple-trapped ions and, hence, the neutral particle fluxes, show jumps in times shorter than 1 ms. According to [1,2] the response time of the density and the fluxes to a sudden jump in the radial electric field is less than 200 μs, if the halfwidth of the electric field is larger or about 2 cm. This would exclude rapid jumps in the radial electric field at the transition. Whether the halfwidth of the electric field is that large during transition cannot be decided from the measurement of the fluxes alone. (orig.)
Finite-difference solution of the space-angle-lethargy-dependent slowing-down transport equation
Energy Technology Data Exchange (ETDEWEB)
Matausek, M V [Boris Kidric Vinca Institute of Nuclear Sciences, Vinca, Belgrade (Yugoslavia)
1972-07-01
A procedure has been developed for solving the slowing-down transport equation for a cylindrically symmetric reactor system. The anisotropy of the resonance neutron flux is treated by the spherical harmonics formalism, which reduces the space-angle-Iethargy-dependent transport equation to a matrix integro-differential equation in space and lethargy. Replacing further the lethargy transfer integral by a finite-difference form, a set of matrix ordinary differential equations is obtained, with lethargy-and space dependent coefficients. If the lethargy pivotal points are chosen dense enough so that the difference correction term can be ignored, this set assumes a lower block triangular form and can be solved directly by forward block substitution. As in each step of the finite-difference procedure a boundary value problem has to be solved for a non-homogeneous system of ordinary differential equations with space-dependent coefficients, application of any standard numerical procedure, for example, the finite-difference method or the method of adjoint equations, is too cumbersome and would make the whole procedure practically inapplicable. A simple and efficient approximation is proposed here, allowing analytical solution for the space dependence of the spherical-harmonics flux moments, and hence the derivation of the recurrence relations between the flux moments at successive lethargy pivotal points. According to the procedure indicated above a computer code has been developed for the CDC -3600 computer, which uses the KEDAK nuclear data file. The space and lethargy distribution of the resonance neutrons can be computed in such a detailed fashion as the neutron cross-sections are known for the reactor materials considered. The computing time is relatively short so that the code can be efficiently used, either autonomously, or as part of some complex modular scheme. Typical results will be presented and discussed in order to prove and illustrate the applicability of the
Analytical calculations of neutron slowing down and transport in the constant-cross-section problem
International Nuclear Information System (INIS)
Cacuci, D.G.
1978-01-01
Some aspects of the problem of neutron slowing down and transport in an infinite medium consisting of a single nuclide that scatters elastically and isotropically and has energy-independent cross sections were investigated. The method of singular eigenfunctions was applied to the Boltzmann equation governing the Laplace transform (with respect to the lethargy variable) of the neutron flux. A new sufficient condition for the convergence of the coefficients of the expansion of the scattering kernel in Legendre polynomials was rigorously derived for this energy-dependent problem. Formulas were obtained for the lethargy-dependent spatial moments of the scalar flux that are valid for medium to large lethargies. In deriving these formulas, use was made of the well-known connection between the spatial moments of the Laplace-transformed scalar flux and the moments of the flux in the ''eigenvalue space.'' The calculations were greatly aided by the construction of a closed general expression for these ''eigenvalue space'' moments. Extensive use was also made of the methods of combinatorial analysis and of computer evaluation, via FORMAC, of complicated sequences of manipulations. For the case of no absorption it was possible to obtain for materials of any atomic weight explicit corrections to the age-theory formulas for the spatial moments M/sub 2n/(u) of the scalar flux that are valid through terms of the order of u -5 . The evaluation of the coefficients of the powers of n, as explicit functions of the nuclear mass, is one of the end products of this investigation. In addition, an exact expression for the second spatial moment, M 2 (u), valid for arbitrary (constant) absorption, was derived. It is now possible to calculate analytically and rigorously the ''age'' for the constant-cross-section problem for arbitrary (constant) absorption and nuclear mass. 5 figures, 1 table
Analytical calculations of neutron slowing down and transport in the constant-cross-section problem
International Nuclear Information System (INIS)
Cacuci, D.G.
1978-04-01
Aspects of the problem of neutron slowing down and transport in an infinite medium consisting of a single nuclide that scatters elastically and isotropically and has energy-independent cross sections were investigated. The method of singular eigenfunctions was applied to the Boltzmann Equation governing the Laplace transform (with respect to the lethargy variable) of the neutron flux. A new sufficient condition for the convergence of the coefficients of the expansion of the scattering kernel in Legendre polynomials was rigorously derived for this energy-dependent problem. Formulas were obtained for the lethargy-dependent spatial moments of the scalar flux that are valid for medium to large lethargies. Use was made of the well-known connection between the spatial moments of the Laplace-transformed scalar flux and the moments of the flux in the ''eigenvalue space.'' The calculations were aided by the construction of a closed general expression for these ''eigenvalue space'' moments. Extensive use was also made of the methods of combinatorial analysis and of computer evaluation of complicated sequences of manipulations. For the case of no absorption it was possible to obtain for materials of any atomic weight explicit corrections to the age-theory formulas for the spatial moments M/sub 2n/(u) of the scalar flux that are valid through terms of the order of u -5 . The evaluation of the coefficients of the powers of n, as explicit functions of the nuclear mass, represent one of the end products of this investigation. In addition, an exact expression for the second spatial moment, M 2 (u), valid for arbitrary (constant) absorption, was derived. It is now possible to calculate analytically and rigorously the ''age'' for the constant-cross-section problem for arbitrary (constant) absorption and nuclear mass. 5 figures, 1 table
Isotopic fissile assay of spent fuel in a lead slowing-down spectrometer system
Energy Technology Data Exchange (ETDEWEB)
Lee, Yong Deok; Jeon, Ju Young [Dept. of Fuel Cycle Technology, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Chang Je [Dept. of Nuclear Engineering, Sejong University, Seoul (Korea, Republic of)
2017-04-15
A lead slowing-down spectrometer (LSDS) system is under development to analyze isotopic fissile content that is applicable to spent fuel and recycled material. The source neutron mechanism for efficient and effective generation was also determined. The source neutron interacts with a lead medium and produces continuous neutron energy, and this energy generates dominant fission at each fissile, below the unresolved resonance region. From the relationship between the induced fissile fission and the fast fission neutron detection, a mathematical assay model for an isotopic fissile material was set up. The assay model can be expanded for all fissile materials. The correction factor for self-shielding was defined in the fuel assay area. The corrected fission signature provides well-defined fission properties with an increase in the fissile content. The assay procedure was also established. The assay energy range is very important to take into account the prominent fission structure of each fissile material. Fission detection occurred according to the change of the Pu239 weight percent (wt%), but the content of U235 and Pu241 was fixed at 1 wt%. The assay result was obtained with 2∼3% uncertainty for Pu239, depending on the amount of Pu239 in the fuel. The results show that LSDS is a very powerful technique to assay the isotopic fissile content in spent fuel and recycled materials for the reuse of fissile materials. Additionally, a LSDS is applicable during the optimum design of spent fuel storage facilities and their management. The isotopic fissile content assay will increase the transparency and credibility of spent fuel storage.
Analytical calculations of neutron slowing down and transport in the constant-cross-section problem
Energy Technology Data Exchange (ETDEWEB)
Cacuci, D.G.
1978-04-01
Aspects of the problem of neutron slowing down and transport in an infinite medium consisting of a single nuclide that scatters elastically and isotropically and has energy-independent cross sections were investigated. The method of singular eigenfunctions was applied to the Boltzmann Equation governing the Laplace transform (with respect to the lethargy variable) of the neutron flux. A new sufficient condition for the convergence of the coefficients of the expansion of the scattering kernel in Legendre polynomials was rigorously derived for this energy-dependent problem. Formulas were obtained for the lethargy-dependent spatial moments of the scalar flux that are valid for medium to large lethargies. Use was made of the well-known connection between the spatial moments of the Laplace-transformed scalar flux and the moments of the flux in the ''eigenvalue space.'' The calculations were aided by the construction of a closed general expression for these ''eigenvalue space'' moments. Extensive use was also made of the methods of combinatorial analysis and of computer evaluation of complicated sequences of manipulations. For the case of no absorption it was possible to obtain for materials of any atomic weight explicit corrections to the age-theory formulas for the spatial moments M/sub 2n/(u) of the scalar flux that are valid through terms of the order of u/sup -5/. The evaluation of the coefficients of the powers of n, as explicit functions of the nuclear mass, represent one of the end products of this investigation. In addition, an exact expression for the second spatial moment, M/sub 2/(u), valid for arbitrary (constant) absorption, was derived. It is now possible to calculate analytically and rigorously the ''age'' for the constant-cross-section problem for arbitrary (constant) absorption and nuclear mass. 5 figures, 1 table.
Design optimization of radiation shielding structure for lead slowing-down spectrometer system
Directory of Open Access Journals (Sweden)
Jeong Dong Kim
2015-04-01
Full Text Available A lead slowing-down spectrometer (LSDS system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea is planned to utilize a high-flux (>1012 n/cm2·s neutron source comprised of a high-energy (30 MeV/high-current (∼2 A electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h, a few shielding materials [high-density polyethylene (HDPE–Borax, B4C, and Li2CO3] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in the near
Lead Slowing-Down Spectrometry Time Spectral Analysis for Spent Fuel Assay: FY12 Status Report
Energy Technology Data Exchange (ETDEWEB)
Kulisek, Jonathan A.; Anderson, Kevin K.; Casella, Andrew M.; Siciliano, Edward R.; Warren, Glen A.
2012-09-28
Executive Summary Developing a method for the accurate, direct, and independent assay of the fissile isotopes in bulk materials (such as used fuel) from next-generation domestic nuclear fuel cycles is a goal of the Office of Nuclear Energy, Fuel Cycle R&D, Material Protection and Control Technology (MPACT) Campaign. To meet this goal, MPACT supports a multi-institutional collaboration, of which PNNL is a part, to study the feasibility of Lead Slowing Down Spectroscopy (LSDS). This technique is an active nondestructive assay method that has the potential to provide independent, direct measurement of Pu and U isotopic masses in used fuel with an uncertainty considerably lower than the approximately 10% typical of today’s confirmatory methods. This document is a progress report for FY2012 PNNL analysis and algorithm development. Progress made by PNNL in FY2012 continues to indicate the promise of LSDS analysis and algorithms applied to used fuel assemblies. PNNL further refined the semi-empirical model developed in FY2011 based on singular value decomposition (SVD) to numerically account for the effects of self-shielding. The average uncertainty in the Pu mass across the NGSI-64 fuel assemblies was shown to be less than 3% using only six calibration assemblies with a 2% uncertainty in the isotopic masses. When calibrated against the six NGSI-64 fuel assemblies, the algorithm was able to determine the total Pu mass within <2% uncertainty for the 27 diversion cases also developed under NGSI. Two purely empirical algorithms were developed that do not require the use of Pu isotopic fission chambers. The semi-empirical and purely empirical algorithms were successfully tested using MCNPX simulations as well applied to experimental data measured by RPI using their LSDS. The algorithms were able to describe the 235U masses of the RPI measurements with an average uncertainty of 2.3%. Analyses were conducted that provided valuable insight with regard to design requirements (e
Design optimization of radiation shielding structure for lead slowing-down spectrometer system
Energy Technology Data Exchange (ETDEWEB)
Kim, Jeong Dong; Ahn, Sang Joon; Lee, Yong Deok [Nonproliferation System Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Chang Je [Dept. of Nuclear Engineering, Sejong University, Seoul (Korea, Republic of)
2015-04-15
A lead slowing-down spectrometer (LSDS) system is a promising nondestructive assay technique that enables a quantitative measurement of the isotopic contents of major fissile isotopes in spent nuclear fuel and its pyroprocessing counterparts, such as 235U, 239Pu, 241Pu, and, potentially, minor actinides. The LSDS system currently under development at the Korea Atomic Energy Research Institute (Daejeon, Korea) is planned to utilize a high-flux (>101{sup 2n}/cm{sup 2}·s) neutron source comprised of a high-energy (30 MeV)/high-current (∼2 A) electron beam and a heavy metal target, which results in a very intense and complex radiation field for the facility, thus demanding structural shielding to guarantee the safety. Optimization of the structural shielding design was conducted using MCNPX for neutron dose rate evaluation of several representative hypothetical designs. In order to satisfy the construction cost and neutron attenuation capability of the facility, while simultaneously achieving the aimed dose rate limit (<0.06 μSv/h), a few shielding materials [high-density polyethylene (HDPE)–Borax, B{sub 4}C, and Li{sub 2}CO{sub 3}] were considered for the main neutron absorber layer, which is encapsulated within the double-sided concrete wall. The MCNP simulation indicated that HDPE-Borax is the most efficient among the aforementioned candidate materials, and the combined thickness of the shielding layers should exceed 100 cm to satisfy the dose limit on the outside surface of the shielding wall of the facility when limiting the thickness of the HDPE-Borax intermediate layer to below 5 cm. However, the shielding wall must include the instrumentation and installation holes for the LSDS system. The radiation leakage through the holes was substantially mitigated by adopting a zigzag-shape with concrete covers on both sides. The suggested optimized design of the shielding structure satisfies the dose rate limit and can be used for the construction of a facility in
First test experiment to produce the slowed-down RI beam with the momentum-compression mode at RIBF
Energy Technology Data Exchange (ETDEWEB)
Sumikama, T., E-mail: sumikama@ribf.riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tohoku University, Aoba, Sendai 980-8578 (Japan); Ahn, D.S.; Fukuda, N.; Inabe, N.; Kubo, T.; Shimizu, Y.; Suzuki, H.; Takeda, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoi, N. [Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Beaumel, D. [Institut de Physique Nucléaire d’Orsay (IPNO), CNRS/IN2P3, 91405 Orsay (France); Hasegawa, K. [Department of Physics, Tohoku University, Aoba, Sendai 980-8578 (Japan); Ideguchi, E. [Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Imai, N. [Center for Nuclear Study, University of Tokyo, RIKEN Campus, 2-1 Hirosawa, Wako, Saitama 351-0298 (Japan); Kobayashi, T. [Department of Physics, Tohoku University, Aoba, Sendai 980-8578 (Japan); Matsushita, M.; Michimasa, S. [Center for Nuclear Study, University of Tokyo, RIKEN Campus, 2-1 Hirosawa, Wako, Saitama 351-0298 (Japan); Otsu, H. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Shimoura, S. [Center for Nuclear Study, University of Tokyo, RIKEN Campus, 2-1 Hirosawa, Wako, Saitama 351-0298 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan)
2016-06-01
The {sup 82}Ge beam has been produced by the in-flight fission reaction of the {sup 238}U primary beam with 345 MeV/u at the RIKEN RI beam factory, and slowed down to about 15 MeV/u using the energy degraders. The momentum-compression mode was applied to the second stage of the BigRIPS separator to reduce the momentum spread. The energy was successfully reduced down to 13 ± 2.5 MeV/u as expected. The focus was not optimized at the end of the second stage, therefore the beam size was larger than the expectation. The transmission of the second stage was half of the simulated value mainly due to out of focus. The two-stage separation worked very well for the slowed-down beam with the momentum-compression mode.
Носачова, Юлія Вікторівна; Ярошенко, М. М.; Корзун, А. О.; КОРОВЧЕНКО, К. С.
2017-01-01
In this article examined the heavy metals ions and their ability to slow down the corrosion process also the impact of ambient temperature on their effectiveness. Solving the problem of corrosion will reduce the impact of large industrial enterprises on the environment and minimize the economic costs. To do this, plants should create a system without a discharge of waste water that is closed recycling systems, which result is a significant reduction in intake of fresh water from natural sourc...
Hoarau, Quentin
2016-01-01
Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms. PMID:26761792
International Nuclear Information System (INIS)
Kruijf, W.J.M. de; Janssen, A.J.
1994-01-01
Very accurate Mote Carlo calculations with Monte Carlo Code have been performed to serve as reference for benchmark calculations on resonance absorption by U 238 in a typical PWR pin-cell geometry. Calculations with the energy-pointwise slowing down code calculates the resonance absorption accurately. Calculations with the multigroup discrete ordinates code XSDRN show that accurate results can only be achieved with a very fine energy mesh. (authors). 9 refs., 5 figs., 2 tabs
Energy Technology Data Exchange (ETDEWEB)
Stefanovic, D B [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)
1970-07-01
The objective of this work is to describe the new analytical solution of the neutron slowing down equation for infinite monoatomic media with arbitrary energy dependence of cross section. The solution is obtained by introducing Green slowing down functions instead of starting from slowing down equations directly. The previously used methods for calculation of fission neutron spectra in the reactor cell were numerical. The proposed analytical method was used for calculating the space-energy distribution of fast neutrons and number of neutron reactions in a thermal reactor cell. The role of analytical method in solving the neutron slowing down in reactor physics is to enable understating of the slowing down process and neutron transport. The obtained results could be used as standards for testing the accuracy od approximative and practical methods.
International Nuclear Information System (INIS)
Moeller, E.
1965-12-01
The use of the time dependent reaction rate method for the measurement of neutron slowing-down time distributions in hydrogen has been analyzed and applied to the case of sloping down in water. Neutrons with energies of about 1 MeV were slowed down, and the time-dependent neutron density at 1.46 eV and its space dependence was measured with a time resolution of 0.042 μs. The results confirm the well known theory for time-dependent slowing down in hydrogen. The space dependence of the distributions is well described by the P 1 -calculations by Claesson
Energy Technology Data Exchange (ETDEWEB)
Moeller, E
1965-12-15
The use of the time dependent reaction rate method for the measurement of neutron slowing-down time distributions in hydrogen has been analyzed and applied to the case of sloping down in water. Neutrons with energies of about 1 MeV were slowed down, and the time-dependent neutron density at 1.46 eV and its space dependence was measured with a time resolution of 0.042 {mu}s. The results confirm the well known theory for time-dependent slowing down in hydrogen. The space dependence of the distributions is well described by the P{sub 1}-calculations by Claesson.
International Nuclear Information System (INIS)
Tone, Tatsuzo
1978-07-01
Described are the reactivity coefficient of D-T fusion reaction, slowing-down processes of deuterons injected with high energy and 3.52 MeV alpha particles generated in D-T reaction, and the power balance in a Tokamak reactor plasma. Most of the results were obtained in the first preliminary design of JAERI Experimental Fusion Reactor (JXFR) driven with stationary neutral beam injection. A manual of numerical computation program ''BALTOK'' developed for the calculations is given in the appendix. (auth.)
International Nuclear Information System (INIS)
Fischer, T; Vink, R L C
2010-01-01
Computer simulations of first-order phase transitions using 'standard' toroidal boundary conditions are generally hampered by exponential slowing down. This is partly due to interface formation, and partly due to shape transitions. The latter occur when droplets become large such that they self-interact through the periodic boundaries. On a spherical simulation topology, however, shape transitions are absent. We expect that by using an appropriate bias function, exponential slowing down can be largely eliminated. In this work, these ideas are applied to the two-dimensional Widom-Rowlinson mixture confined to the surface of a sphere. Indeed, on the sphere, we find that the number of Monte Carlo steps needed to sample a first-order phase transition does not increase exponentially with system size, but rather as a power law τ∝V α , with α∼2.5, and V the system area. This is remarkably close to a random walk for which α RW = 2. The benefit of this improved scaling behavior for biased sampling methods, such as the Wang-Landau algorithm, is investigated in detail.
Energy Technology Data Exchange (ETDEWEB)
Belayche, P; Chavy, P; Dupoux, M; Salmon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1961-07-01
Numerical solution of the Fokker-Planck equation applied to the slowing down of tritons in a deuterium plasma. After the equations and the boundary conditions have been written, some attention is paid to the numerical tricks used to run the problem on a high speed electronic computer. The numerical results thus obtained are then analyzed and as far as possible, mathematically explained. (authors) [French] Resolution numerique de l'equation de Fokker-Planck appliquee au ralentissement de tritons dans un plasma de deuterium. Apres avoir rappele les equations, les conditions aux limites, l'accent est mis sur les artifices numeriques utilises pour traiter le probleme sur une calculatrice a grande vitesse. Les resultats numeriques obtenus sont ensuite analyses et si possible expliques mathematiquement. En particulier ils peuvent se rattacher a ceux obtenus par application directe de la formule de Spitzer. (auteurs)
Trofimov, Vyacheslav A.; Lysak, Tatiana M.
2018-04-01
We investigate both numerically and analytically the spectrum evolution of a novel type soliton - nonlinear chirped accelerating or decelerating soliton - at a femtosecond pulse propagation in a medium containing noble nanoparticles. In our consideration, we take into account one- or two-photon absorption of laser radiation by nanorods, and time-dependent nanorod aspect ratio changing due to their melting or reshaping because of laser energy absorption. The chirped solitons are formed due to the trapping of laser radiation by the nanorods reshaping fronts, if a positive or negative phase-amplitude grating is induced by laser radiation. Accelerating or slowing down chirped soliton formation is accompanied by the soliton spectrum blue or red shift. To prove our numerical results, we derived the approximate analytical law for the spectrum maximum intensity evolution along the propagation coordinate, based on earlier developed approximate analytical solutions for accelerating and decelerating solitons.
Energy Technology Data Exchange (ETDEWEB)
Kulisek, Jonathan A.; Anderson, Kevin K.; Casella, Andrew M.; Gesh, Christopher J.; Warren, Glen A.; Gavron, Victor A.; Devlin, M.; Haight, R. C.; O' Donnell, J. M.; Danon, Yaron; Weltz, Adam; Bonebrake, Eric; Imel, G. R.; Harris, Jason; Beller, Dennis; Hatchett, D.; Droessler, J.
2012-08-30
Developing a method for the accurate, direct, and independent assay of the fissile isotopes in bulk materials (such as used fuel) from next-generation domestic nuclear fuel cycles is a goal of the Office of Nuclear Energy, Fuel Cycle R&D, Material Protection and Control Technology (MPACT) Campaign. To meet this goal, MPACT supports a multi-institutional collaboration to study the feasibility of Lead Slowing Down Spectroscopy. This technique is an active nondestructive assay method that has the potential to provide independent, direct measurement of Pu and U isotopic masses in used fuel with an uncertainty considerably lower than the approximately 10% typical of today’s confirmatory assay methods. This paper will present efforts on the development of time-spectral analysis algorithms, fast neutron detector advances, and validation and testing measurements.
Energy Technology Data Exchange (ETDEWEB)
Fiks, E.I.; Pivovarov, Yu.L.
2015-07-15
Theoretical analysis and representative calculations of angular and spectral distributions of X-ray Transition Radiation (XTR) by Relativistic Heavy Ions (RHI) crossing a radiator are presented taking into account both XTR absorption and RHI slowing-down. The calculations are performed for RHI energies of GSI, FAIR, CERN SPS and LHC and demonstrate the influence of XTR photon absorption as well as RHI slowing-down in a radiator on the appearance/disappearance of interference effects in both angular and spectral distributions of XTR.
International Nuclear Information System (INIS)
Smith, Leon E.; Haas, Derek A.; Gavron, Victor A.; Imel, G.R.; Ressler, Jennifer J.; Bowyer, Sonya M.; Danon, Y.; Beller, D.
2009-01-01
Under funding from the Department of Energy Office of Nuclear Energy's Materials, Protection, Accounting, and Control for Transmutation (MPACT) program (formerly the Advanced Fuel Cycle Initiative Safeguards Campaign), Pacific Northwest National Laboratory (PNNL) and Los Alamos National Laboratory (LANL) are collaborating to study the viability of lead slowing-down spectroscopy (LSDS) for spent-fuel assay. Based on the results of previous simulation studies conducted by PNNL and LANL to estimate potential LSDS performance, a more comprehensive study of LSDS viability has been defined. That study includes benchmarking measurements, development and testing of key enabling instrumentation, and continued study of time-spectra analysis methods. This report satisfies the requirements for a PNNL/LANL deliverable that describes the objectives, plans and contributing organizations for a comprehensive three-year study of LSDS for spent-fuel assay. This deliverable was generated largely during the LSDS workshop held on August 25-26, 2009 at Rensselaer Polytechnic Institute (RPI). The workshop itself was a prominent milestone in the FY09 MPACT project and is also described within this report.
Ghosh, Shampa; Sinha, Jitendra Kumar; Raghunath, Manchala
2016-09-01
DNA damage caused by various sources remains one of the most researched topics in the area of aging and neurodegeneration. Increased DNA damage causes premature aging. Aging is plastic and is characterised by the decline in the ability of a cell/organism to maintain genomic stability. Lifespan can be modulated by various interventions like calorie restriction, a balanced diet of macro and micronutrients or supplementation with nutrients/nutrient formulations such as Amalaki rasayana, docosahexaenoic acid, resveratrol, curcumin, etc. Increased levels of DNA damage in the form of double stranded and single stranded breaks are associated with decreased longevity in animal models like WNIN/Ob obese rats. Erroneous DNA repair can result in accumulation of DNA damage products, which in turn result in premature aging disorders such as Hutchinson-Gilford progeria syndrome. Epigenomic studies of the aging process have opened a completely new arena for research and development of drugs and therapeutic agents. We propose here that agents or interventions that can maintain epigenomic stability and facilitate the DNA repair process can slow down the progress of premature aging, if not completely prevent it. © 2016 IUBMB Life, 68(9):717-721, 2016. © 2016 International Union of Biochemistry and Molecular Biology.
Godoy, Oscar; Castro-Díez, Pilar; Van Logtestijn, Richard S P; Cornelissen, Johannes H C; Valladares, Fernando
2010-03-01
Leaf traits related to the performance of invasive alien species can influence nutrient cycling through litter decomposition. However, there is no consensus yet about whether there are consistent differences in functional leaf traits between invasive and native species that also manifest themselves through their "after life" effects on litter decomposition. When addressing this question it is important to avoid confounding effects of other plant traits related to early phylogenetic divergences and to understand the mechanism underlying the observed results to predict which invasive species will exert larger effects on nutrient cycling. We compared initial leaf litter traits, and their effect on decomposability as tested in standardized incubations, in 19 invasive-native pairs of co-familial species from Spain. They included 12 woody and seven herbaceous alien species representative of the Spanish invasive flora. The predictive power of leaf litter decomposition rates followed the order: growth form > family > status (invasive vs. native) > leaf type. Within species pairs litter decomposition tended to be slower and more dependent on N and P in invaders than in natives. This difference was likely driven by the higher lignin content of invader leaves. Although our study has the limitation of not representing the natural conditions from each invaded community, it suggests a potential slowing down of the nutrient cycle at ecosystem scale upon invasion.
de Filippo, E.; Lanzanó, G.; Amorini, F.; Cardella, G.; Geraci, E.; Grassi, L.; La Guidara, E.; Lombardo, I.; Politi, G.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.
2010-12-01
The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.
International Nuclear Information System (INIS)
De Filippo, E.; Lanzano, G.; Cardella, G.; Amorini, F.; Geraci, E.; Grassi, L.; Politi, G.; La Guidara, E.; Lombardo, I.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.
2010-01-01
The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.
Directory of Open Access Journals (Sweden)
Tian Liu
2015-01-01
Full Text Available MicroRNA-124 contributes to neurogenesis through regulating its targets, but its expression both in the brain of Huntington′s disease mouse models and patients is decreased. However, the effects of microRNA-124 on the progression of Huntington′s disease have not been reported. Results from this study showed that microRNA-124 increased the latency to fall for each R6/2 Huntington′s disease transgenic mouse in the rotarod test. 5-Bromo-2′-deoxyuridine (BrdU staining of the striatum shows an increase in neurogenesis. In addition, brain-derived neurotrophic factor and peroxisome proliferator-activated receptor gamma coactivator 1-alpha protein levels in the striatum were increased and SRY-related HMG box transcription factor 9 protein level was decreased. These findings suggest that microRNA-124 slows down the progression of Huntington′s disease possibly through its important role in neuronal differentiation and survival.
Directory of Open Access Journals (Sweden)
Bruno eNicenboim
2016-03-01
Full Text Available We examined the effects of argument-head distance in SVO and SOV languages (Spanish and German, while taking into account readers’ working memory capacity and controlling for expectation (Levy, 2008 and other factors. We predicted only locality effects, that is, a slow-down produced by increased dependency distance (Gibson, 2000; Lewis & Vasishth, 2005. Furthermore, we expected stronger locality effects for readers with low working memory capacity. Contrary to our predictions, low-capacity readers showed faster reading with increased distance, while high-capacity readers showed locality effects. We suggest that while the locality effects are compatible with memory-based explanations, the speedup of low-capacity readers can be explained by an increased probability of retrieval failure. We present a computational model based on ACT-R built under the previous assumptions, which is able to give a qualitative account for the present data and can be tested in future research. Our results suggest that in some cases, interpreting longer RTs as indexing increased processing difficulty and shorter RTs as facilitation may be too simplistic: The same increase in processing difficulty may lead to slowdowns in high-capacity readers and speedups in low-capacity ones. Ignoring individual level capacity differences when investigating locality effects may lead to misleading conclusions.
FOXO/DAF-16 Activation Slows Down Turnover of the Majority of Proteins in C. elegans.
Dhondt, Ineke; Petyuk, Vladislav A; Cai, Huaihan; Vandemeulebroucke, Lieselot; Vierstraete, Andy; Smith, Richard D; Depuydt, Geert; Braeckman, Bart P
2016-09-13
Most aging hypotheses assume the accumulation of damage, resulting in gradual physiological decline and, ultimately, death. Avoiding protein damage accumulation by enhanced turnover should slow down the aging process and extend the lifespan. However, lowering translational efficiency extends rather than shortens the lifespan in C. elegans. We studied turnover of individual proteins in the long-lived daf-2 mutant by combining SILeNCe (stable isotope labeling by nitrogen in Caenorhabditiselegans) and mass spectrometry. Intriguingly, the majority of proteins displayed prolonged half-lives in daf-2, whereas others remained unchanged, signifying that longevity is not supported by high protein turnover. This slowdown was most prominent for translation-related and mitochondrial proteins. In contrast, the high turnover of lysosomal hydrolases and very low turnover of cytoskeletal proteins remained largely unchanged. The slowdown of protein dynamics and decreased abundance of the translational machinery may point to the importance of anabolic attenuation in lifespan extension, as suggested by the hyperfunction theory. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.
FOXO/DAF-16 Activation Slows Down Turnover of the Majority of Proteins in C. elegans
Directory of Open Access Journals (Sweden)
Ineke Dhondt
2016-09-01
Full Text Available Most aging hypotheses assume the accumulation of damage, resulting in gradual physiological decline and, ultimately, death. Avoiding protein damage accumulation by enhanced turnover should slow down the aging process and extend the lifespan. However, lowering translational efficiency extends rather than shortens the lifespan in C. elegans. We studied turnover of individual proteins in the long-lived daf-2 mutant by combining SILeNCe (stable isotope labeling by nitrogen in Caenorhabditis elegans and mass spectrometry. Intriguingly, the majority of proteins displayed prolonged half-lives in daf-2, whereas others remained unchanged, signifying that longevity is not supported by high protein turnover. This slowdown was most prominent for translation-related and mitochondrial proteins. In contrast, the high turnover of lysosomal hydrolases and very low turnover of cytoskeletal proteins remained largely unchanged. The slowdown of protein dynamics and decreased abundance of the translational machinery may point to the importance of anabolic attenuation in lifespan extension, as suggested by the hyperfunction theory.
Tardif, Carole; Laine, France; Rodriguez, Melissa; Gepner, Bruno
2007-01-01
This study examined the effects of slowing down presentation of facial expressions and their corresponding vocal sounds on facial expression recognition and facial and/or vocal imitation in children with autism. Twelve autistic children and twenty-four normal control children were presented with emotional and non-emotional facial expressions on…
Brighenti, Elisa; Giannone, Ferdinando Antonino; Fornari, Francesca; Onofrillo, Carmine; Govoni, Marzia; Montanaro, Lorenzo; Treré, Davide; Derenzini, Massimo
2016-01-01
Chronic inflammation is a risk factor for the onset of cancer and the regular use of aspirin reduces the risk of cancer development. Here we showed that therapeutic dosages of aspirin counteract the pro-tumorigenic effects of the inflammatory cytokine interleukin(IL)-6 in cancer and non-cancer cell lines, and in mouse liver in vivo. We found that therapeutic dosages of aspirin prevented IL-6 from inducing the down-regulation of p53 expression and the acquisition of the epithelial mesenchymal transition (EMT) phenotypic changes in the cell lines. This was the result of a reduction in c-Myc mRNA transcription which was responsible for a down-regulation of the ribosomal protein S6 expression which, in turn, slowed down the rRNA maturation process, thus reducing the ribosome biogenesis rate. The perturbation of ribosome biogenesis hindered the Mdm2-mediated proteasomal degradation of p53, throughout the ribosomal protein-Mdm2-p53 pathway. P53 stabilization hindered the IL-6 induction of the EMT changes. The same effects were observed in livers from mice stimulated with IL-6 and treated with aspirin. It is worth noting that aspirin down-regulated ribosome biogenesis, stabilized p53 and up-regulated E-cadherin expression in unstimulated control cells also. In conclusion, these data showed that therapeutic dosages of aspirin increase the p53-mediated tumor-suppressor activity of the cells thus being in this way able to reduce the risk of cancer onset, either or not linked to chronic inflammatory processes. PMID:27557515
Brighenti, Elisa; Giannone, Ferdinando Antonino; Fornari, Francesca; Onofrillo, Carmine; Govoni, Marzia; Montanaro, Lorenzo; Treré, Davide; Derenzini, Massimo
2016-09-27
Chronic inflammation is a risk factor for the onset of cancer and the regular use of aspirin reduces the risk of cancer development. Here we showed that therapeutic dosages of aspirin counteract the pro-tumorigenic effects of the inflammatory cytokine interleukin(IL)-6 in cancer and non-cancer cell lines, and in mouse liver in vivo. We found that therapeutic dosages of aspirin prevented IL-6 from inducing the down-regulation of p53 expression and the acquisition of the epithelial mesenchymal transition (EMT) phenotypic changes in the cell lines. This was the result of a reduction in c-Myc mRNA transcription which was responsible for a down-regulation of the ribosomal protein S6 expression which, in turn, slowed down the rRNA maturation process, thus reducing the ribosome biogenesis rate. The perturbation of ribosome biogenesis hindered the Mdm2-mediated proteasomal degradation of p53, throughout the ribosomal protein-Mdm2-p53 pathway. P53 stabilization hindered the IL-6 induction of the EMT changes. The same effects were observed in livers from mice stimulated with IL-6 and treated with aspirin. It is worth noting that aspirin down-regulated ribosome biogenesis, stabilized p53 and up-regulated E-cadherin expression in unstimulated control cells also. In conclusion, these data showed that therapeutic dosages of aspirin increase the p53-mediated tumor-suppressor activity of the cells thus being in this way able to reduce the risk of cancer onset, either or not linked to chronic inflammatory processes.
International Nuclear Information System (INIS)
Peng, W.H.
1977-01-01
A specialized moments-method computer code was constructed for the calculation of the even spatial moments of the scalar flux, phi/sub 2n/, through 2n = 80. Neutron slowing-down and transport in a medium with constant cross sections was examined and the effect of a superimposed square-well cross section minimum on the penetrating flux was studied. In the constant cross section case, for nuclei that are not too light, the scalar flux is essentially independent of the nuclide mass. The numerical results obtained were used to test the validity of existing analytic approximations to the flux at both small and large lethargies relative to the source energy. As a result it was possible to define the regions in the lethargy--distance plane where these analytic solutions apply with reasonable accuracy. A parametric study was made of the effect of a square-well cross section minimum on neutron fluxes at energies below the minimum. It was shown that the flux at energies well below the minimum is essentially independent of the position of the minimum in lethargy. The results can be described by a convolution-of-sources model involving only the lethargy separation between detector and source, the width and the relative depth of the minimum. On the basis of the computations and the corresponding model, it is possible to predict, e.g., the conditions under which transport in the region of minimum completely determines the penetrating flux. At the other extreme, the model describes when the transport in the minimum can be treated in the same manner as in any comparable lethargy interval. With the aid of these criteria it is possible to understand the apparent paradoxical effects of certain minima in neutron penetration through such media as iron and sodium
Directory of Open Access Journals (Sweden)
Nerina Vischer
Full Text Available The costs, complexity, legal requirements and number of amendments associated with clinical trials are rising constantly, which negatively affects the efficient conduct of trials. In Sub-Saharan Africa, this situation is exacerbated by capacity and funding limitations, which further increase the workload of clinical trialists. At the same time, trials are critically important for improving public health in these settings. The aim of this study was to identify the internal factors that slow down clinical trials in Sub-Saharan Africa. Here, factors are limited to those that exclusively relate to clinical trial teams and sponsors. These factors may be influenced independently of external conditions and may significantly increase trial efficiency if addressed by the respective teams.We conducted sixty key informant interviews with clinical trial staff working in different positions in two clinical research centres in Kenya, Ghana, Burkina Faso and Senegal. The study covered English- and French-speaking, and Eastern and Western parts of Sub-Saharan Africa. We performed thematic analysis of the interview transcripts.We found various internal factors associated with slowing down clinical trials; these were summarised into two broad themes, "planning" and "site organisation". These themes were consistently mentioned across positions and countries. "Planning" factors related to budget feasibility, clear project ideas, realistic deadlines, understanding of trial processes, adaptation to the local context and involvement of site staff in planning. "Site organisation" factors covered staff turnover, employment conditions, career paths, workload, delegation and management.We found that internal factors slowing down clinical trials are of high importance to trial staff. Our data suggest that adequate and coherent planning, careful assessment of the setting, clear task allocation and management capacity strengthening may help to overcome the identified
International Nuclear Information System (INIS)
Dulieu, P.
1967-11-01
There are no complete theory nor experimental data sufficient to predict exactly, in a systemic way, the slowing down power of any medium for any ion with any energy. However, in each case, the energy range can be divided in three areas, the low energiy range where the de/dx is an ascending energy function, the intermediate energy region where de/dx has a maximum, the high energy region where de/dx is a descending energy function. In practice, the code Irma 3 allows to obtain with a good precision de/dx for the protons, neutrons, tritons, alphas in any medium. For particles heavier than alpha it is better to use specific methods. In the case of calculating the yield of the (alpha, neutron) reaction in a UO 2 -PuO 2 fuel cell, the divergences of experimental origin, between the existing data lead to adopt a range a factor 1.7 on the yields [fr
International Nuclear Information System (INIS)
Long, K.A.; Moritz, N.; Tahir, N.A.
1983-11-01
The computer code GORGON, which calculates the energy deposition and slowing down of ions in cold materials and hot plasmas is described, and analyzed in this report. This code is in a state of continuous development but an intermediate stage has been reached where it is considered useful to document the 'state of the art' at the present time. The GORGON code is an improved version of a code developed by Zinamon et al. as part of a more complex program system for studying the hydrodynamic motion of plane metal targets irradiated by intense beams of protons. The improvements made in the code were necessary to improve its usefulness for problems related to the design and burn of heavy ion beam driven inertial confinement fusion targets. (orig./GG) [de
International Nuclear Information System (INIS)
Konefal, Adam; Laciak, Marcin; Dawidowska, Anna; Osewski, Wojciech
2014-01-01
The detailed analysis of nuclear reactions occurring in materials of the door is presented for the typical construction of an entrance door to a room with a slowed down neutron field. The changes in the construction of the door were determined to reduce effectively the level of neutron and gamma radiation in the vicinity of the door in a room adjoining the neutron field room. Optimisation of the door construction was performed with the use of Monte Carlo calculations (GEANT4). The construction proposed in this paper bases on the commonly used inexpensive protective materials such as borax (13.4 cm), lead (4 cm) and stainless steel (0.1 and 0.5 cm on the side of the neutron field room and of the adjoining room, respectively). The improved construction of the door, worked out in the presented studies, can be an effective protection against neutrons with energies up to 1 MeV (authors)
Energy Technology Data Exchange (ETDEWEB)
Latysheva, L. N.; Bergman, A. A.; Sobolevsky, N. M., E-mail: sobolevs@inr.ru [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation); Ilic, R. D. [Vinca Institute of Nuclear Sciences (Serbia)
2013-04-15
Lead slowing-down (LSD) spectrometers have a low energy resolution (about 30%), but their luminosity is 10{sup 3} to 10{sup 4} times higher than that of time-of-flight (TOF) spectrometers. A high luminosity of LSD spectrometers makes it possible to use them to measure neutron cross section for samples of mass about several micrograms. These features specify a niche for the application of LSD spectrometers in measuring neutron cross sections for elements hardly available in macroscopic amounts-in particular, for actinides. A mathematical simulation of the parameters of SVZ-100 LSD spectrometer of the Institute for Nuclear Research (INR, Moscow) is performed in the present study on the basis of the MCNPX code. It is found that the moderation constant, which is the main parameter of LSD spectrometers, is highly sensitive to the size and shape of detecting volumes in calculations and, hence, to the real size of experimental channels of the LSD spectrometer.
International Nuclear Information System (INIS)
Latysheva, L. N.; Bergman, A. A.; Sobolevsky, N. M.; Ilić, R. D.
2013-01-01
Lead slowing-down (LSD) spectrometers have a low energy resolution (about 30%), but their luminosity is 10 3 to 10 4 times higher than that of time-of-flight (TOF) spectrometers. A high luminosity of LSD spectrometers makes it possible to use them to measure neutron cross section for samples of mass about several micrograms. These features specify a niche for the application of LSD spectrometers in measuring neutron cross sections for elements hardly available in macroscopic amounts—in particular, for actinides. A mathematical simulation of the parameters of SVZ-100 LSD spectrometer of the Institute for Nuclear Research (INR, Moscow) is performed in the present study on the basis of the MCNPX code. It is found that the moderation constant, which is the main parameter of LSD spectrometers, is highly sensitive to the size and shape of detecting volumes in calculations and, hence, to the real size of experimental channels of the LSD spectrometer.
Information slows down hierarchy growth.
Czaplicka, Agnieszka; Suchecki, Krzysztof; Miñano, Borja; Trias, Miquel; Hołyst, Janusz A
2014-06-01
We consider models of growing multilevel systems wherein the growth process is driven by rules of tournament selection. A system can be conceived as an evolving tree with a new node being attached to a contestant node at the best hierarchy level (a level nearest to the tree root). The proposed evolution reflects limited information on system properties available to new nodes. It can also be expressed in terms of population dynamics. Two models are considered: a constant tournament (CT) model wherein the number of tournament participants is constant throughout system evolution, and a proportional tournament (PT) model where this number increases proportionally to the growing size of the system itself. The results of analytical calculations based on a rate equation fit well to numerical simulations for both models. In the CT model all hierarchy levels emerge, but the birth time of a consecutive hierarchy level increases exponentially or faster for each new level. The number of nodes at the first hierarchy level grows logarithmically in time, while the size of the last, "worst" hierarchy level oscillates quasi-log-periodically. In the PT model, the occupations of the first two hierarchy levels increase linearly, but worse hierarchy levels either do not emerge at all or appear only by chance in the early stage of system evolution to further stop growing at all. The results allow us to conclude that information available to each new node in tournament dynamics restrains the emergence of new hierarchy levels and that it is the absolute amount of information, not relative, which governs such behavior.
Slowing down with resonance absorption
International Nuclear Information System (INIS)
Moura Neto, C. de; Nair, R.P.K.
1979-08-01
The presence of heavy nuclei in nuclear reactors, in significant concentrations, facilitates the appearance of absorption resonances. For the moderation in the presence of absorbers an exact solution of the integral equations is possible by numerical methods. Approximated solutions for separated resonances in function of the practical width, (NR and NRIM approximations) are discussed in this paper. The method is generalized, presenting the solution by an intermediate approximation, in the definition of the resonance integral. (Author) [pt
Information slows down hierarchy growth
Czaplicka, Agnieszka; Suchecki, Krzysztof; Miñano, Borja; Trias, Miquel; Hołyst, Janusz A.
2014-06-01
We consider models of growing multilevel systems wherein the growth process is driven by rules of tournament selection. A system can be conceived as an evolving tree with a new node being attached to a contestant node at the best hierarchy level (a level nearest to the tree root). The proposed evolution reflects limited information on system properties available to new nodes. It can also be expressed in terms of population dynamics. Two models are considered: a constant tournament (CT) model wherein the number of tournament participants is constant throughout system evolution, and a proportional tournament (PT) model where this number increases proportionally to the growing size of the system itself. The results of analytical calculations based on a rate equation fit well to numerical simulations for both models. In the CT model all hierarchy levels emerge, but the birth time of a consecutive hierarchy level increases exponentially or faster for each new level. The number of nodes at the first hierarchy level grows logarithmically in time, while the size of the last, "worst" hierarchy level oscillates quasi-log-periodically. In the PT model, the occupations of the first two hierarchy levels increase linearly, but worse hierarchy levels either do not emerge at all or appear only by chance in the early stage of system evolution to further stop growing at all. The results allow us to conclude that information available to each new node in tournament dynamics restrains the emergence of new hierarchy levels and that it is the absolute amount of information, not relative, which governs such behavior.
Neuberger, A; Ring, S; Silva-Vilches, C; Schrader, J; Enk, A; Mahnke, K
2017-09-01
Application of haptens to the skin induces release of immune stimulatory ATP into the extracellular space. This "danger" signal can be converted to immunosuppressive adenosine (ADO) by the action of the ectonucleotidases CD39 and CD73, expressed by skin and immune cells. Thus, the expression and regulation of CD73 by skin derived cells may have crucial influence on the outcome of contact hypersensitivity (CHS) reactions. To investigate the role of CD73 expression during 2,4,6-trinitrochlorobenzene (TNCB) induced CHS reactions. Wild type (wt) and CD73 deficient mice were subjected to TNCB induced CHS. In the different mouse strains the resulting ear swelling reaction was recorded along with a detailed phenotypic analysis of the skin migrating subsets of dendritic cells (DC). In CD73 deficient animals the motility of DC was higher as compared to wt animals and in particular after sensitization we found increased migration of Langerin + DC from skin to draining lymph nodes (LN). In the TNCB model this led to a stronger sensitization as indicated by increased frequency of interferon-γ producing T cells in the LN and an increased ear thickness after challenge. CD73 derived ADO production slows down migration of Langerin + DC from skin to LN. This may be a crucial mechanism to avoid over boarding immune reactions against haptens. Copyright © 2017 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A.; Danon, Y.; Block, R.C.; Slovacek, R.E.; Hoff, R.W.; Lougheed, R.W.
1990-01-01
In November 1989, we carried out a measurement of the fission cross section of 247 Cm, 250 Cf, and 254 Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 μg for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs
Energy Technology Data Exchange (ETDEWEB)
Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A. (Los Alamos National Lab., NM (USA)); Danon, Y.; Block, R.C.; Slovacek, R.E. (Rensselaer Polytechnic Inst., Troy, NY (USA)); Hoff, R.W.; Lougheed, R.W. (Lawrence Livermore National Lab., CA (USA))
1990-01-01
In November 1989, we carried out a measurement of the fission cross section of {sup 247}Cm, {sup 250}Cf, and {sup 254}Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 {mu}g for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs.
Xiong, Wenguang; Wang, Mei; Dai, Jinjun; Sun, Yongxue; Zeng, Zhenling
2018-01-01
Manure application contributes to the increased environmental burden of antibiotic resistance genes (ARGs). We investigated the response of tetracycline (tet) resistance genes and bacterial taxa to manure application amended with tetracyclines over two months. Representative tetracyclines (oxytetracycline, chlorotetracycline and doxycycline), tet resistance genes (tet(M), tet(O), tet(W), tet(S), tet(Q) and tet(X)) and bacterial taxa in the untreated soil, +manure, and +manure+tetracyclines groups were analyzed. The abundances of all tet resistance genes in the +manure group were significantly higher than those in the untreated soil group on day 1. The abundances of all tet resistance genes (except tet(Q) and tet(X)) were significantly lower in the +manure group than those in the +manure+tetracyclines group on day 30 and 60. The dissipation rates were higher in the +manure group than those in the +manure+tetracyclines group. Disturbance of soil bacterial community composition imposed by tetracyclines was also observed. The results indicated that tetracyclines slowed down the dissipation of tet resistance genes in arable soil after manure application. Application of manure amended with tetracyclines may provide a significant selective advantage for species affiliated to the taxonomical families of Micromonosporaceae, Propionibacteriaceae, Streptomycetaceae, Nitrospiraceae and Clostridiaceae. Copyright © 2017 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Ray, E.M.
1991-06-01
This work is devoted to the experimental study of the interaction between fast (10 to 120 keV/p) hydrogen clusters with thin solid targets. First, we have studied the slowing-down of H n + (2≤n≤21) clusters through carbon foils. Up to date this had been made only with molecular ions. We obtain evidence for vicinage effects on the energy loss of proton-clusters. We show that for projectile energies larger than 50 keV/p, the energy loss of a proton in a cluster is enhanced when compared to that of an isolated proton of the same velocity. At lower incident energies, it is a decrease of the energy loss which is observed. The same effect is also observed in the energy lost in the entrance window of a surface barrier detector bombarded by clusters. This phenomenon is interpreted in terms of interferences between individual polarisation wakes induced by each proton of the cluster. In the second part, we propose an accurate method to study the charge state of the atomic fragments resulting from the dissociation of fast H n + (2≤n≤15) clusters through a carbon foil. This method gives also the distribution of the neutral atoms among the emerging fragments. These distributions are finally compared with binomial laws expected from independent particles
Li, Yanxiu; Huang, He; Xiong, Yuan; Kershaw, Stephen V; Rogach, Andrey L
2018-03-24
We developed a microwave-assisted slowed-down synthesis of CsPbBr 3 perovskite nanocrystals, which retards the reaction and allows us to gather useful insights into the formation mechanism of these nanoparticles, by examining the intermediate stages of their growth. The trends in the decay of the emission intensity of CsPbBr 3 nanocrystals under light exposure are well correlated with their stability against decomposition in TEM under electron beam. The results show the change of the crystal structure of CsPbBr 3 nanocrystals from a deficient and easier to be destroyed lattice to a well crystallized one. Conversely the shift in the ease of degradation sheds light on the formation mechanism, indicating first the formation of a bromoplumbate ionic scaffold, with Cs-ion infilling lagging a little behind. Increasing the cation to halide ratio towards the stoichiometric level may account for the improved radiative recombination rates observed in the longer reaction time materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Konefał, Adam; Łaciak, Marcin; Dawidowska, Anna; Osewski, Wojciech
2014-12-01
The detailed analysis of nuclear reactions occurring in materials of the door is presented for the typical construction of an entrance door to a room with a slowed down neutron field. The changes in the construction of the door were determined to reduce effectively the level of neutron and gamma radiation in the vicinity of the door in a room adjoining the neutron field room. Optimisation of the door construction was performed with the use of Monte Carlo calculations (GEANT4). The construction proposed in this paper bases on the commonly used inexpensive protective materials such as borax (13.4 cm), lead (4 cm) and stainless steel (0.1 and 0.5 cm on the side of the neutron field room and of the adjoining room, respectively). The improved construction of the door, worked out in the presented studies, can be an effective protection against neutrons with energies up to 1 MeV. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Energy Technology Data Exchange (ETDEWEB)
Ribon, P; Michaudon, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1965-07-01
The studies of interaction of slow neutrons with atomic nuclei by means of the time of flight methods are made with a pulsed neutron source with a broad energy spectrum. The measurement accuracy needs a high intensity and an output time as short as possible and well defined. If the neutrons source is a target bombarded by the beam of a pulsed accelerator, it is usually required to slow down the neutrons to obtain a sufficient intensity at low energies. The purpose of the Monte-Carlo method which is described in this paper is to study the slowing down properties, mainly the intensity and the output time distribution of the slowed-down neutrons. The choice of the method and parameters studied is explained as well as the principles, some calculations and the program organization. A few results given as examples were obtained in the line of this program, the limits of which are principally due to simplifying physical hypotheses. (author) [French] l'etude de l'interaction des neutrons lents avec les noyaux atomiques par la methode du temps de vol s'effectue avec une source pulsee de neutrons dont le spectre en energie est assez etendu. La precision des mesures demande que la source soit intense et que la duree d'emission des neutrons soit breve et bien definie. Si la source est une cible bombardee par le faisceau de particules d'un accelerateur pulse, il est generalement indispensable de ralentir les neutrons pour avoir une intensite suffisante a basse energie. Nous presentons ici une methode de Monte-Carlo pour l'etude detaillee de ce ralentissement, notamment l'intensite et la distribution des temps de sortie des neutrons ralentis. Cette presentation comprend: la justification du choix de la methode de Monte-Carlo, les principes generaux, les differentes etapes du calcul et du programme ecrit pour le calculateur electronique IBM 7090. Nous indiquons aussi les restrictions qui sont apportees au domaine d'application de ce programme et qui proviennent surtout des
On the theory of slowing down gracefully
Indian Academy of Sciences (India)
2012-06-08
Jun 8, 2012 ... Our analysis of this phenomenon provides a modest ... observed degrees of freedom of a medium such as the electromagnetic field in an optically dense material, sound waves in a crystal or the Goldstone modes of an atom ...
Words can slow down category learning.
Brojde, Chandra L; Porter, Chelsea; Colunga, Eliana
2011-08-01
Words have been shown to influence many cognitive tasks, including category learning. Most demonstrations of these effects have focused on instances in which words facilitate performance. One possibility is that words augment representations, predicting an across the-board benefit of words during category learning. We propose that words shift attention to dimensions that have been historically predictive in similar contexts. Under this account, there should be cases in which words are detrimental to performance. The results from two experiments show that words impair learning of object categories under some conditions. Experiment 1 shows that words hurt performance when learning to categorize by texture. Experiment 2 shows that words also hurt when learning to categorize by brightness, leading to selectively attending to shape when both shape and hue could be used to correctly categorize stimuli. We suggest that both the positive and negative effects of words have developmental origins in the history of word usage while learning categories. [corrected
Neutron slowing down in the resonance region
International Nuclear Information System (INIS)
Matausek, M.V.
1971-01-01
This paper describes the procedure for solving space, lethargy and angular dependent transport equation for resonant neutrons in cylindrical infinite reactor lattice cell. The procedure is suitable for practical application on its own or in combination with some more complex procedure
Energy Technology Data Exchange (ETDEWEB)
Leveque, P; Martinelli, P; Chauvin, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1955-07-01
Inelastic scattering of the {beta}{sup -} particles on the nucleus gives place to the emission of a X-ray Bremsstrahlung radiation. In view of possible industrial applications, we studied the slowing-down radiation of {sup 90}(Sr + Y) sources in various materials. This pure {beta}{sup -} emitter of long period is in the fission products of uranium. Among of the industrial applications, these sources of weak X-rays energy can be used for the radiography of thin pieces, for measuring the thickness, or for the analysis by fluorescence. (M.B.) [French] La diffusion inelastique des particules {beta}{sup -} sur les noyaux donne lieu a l'emission d'un rayonnement X de freinage. En vue de possibles applications industrielles, nous avons etudie le rayonnement de freinage des sources {sup 90}(Sr + Y) dans divers materiaux. Cet emetteur {beta}{sup -} pur a longue periode se trouve dans les produits de fission de l'uranium. Parmi les applications industrielles a l'etude, ces sources de rayons X de faible energie peuvent etre utilisees pour la radiographie de pieces minces, la mesure d'epaisseurs, ou encore pour l'analyse par fluorescence. (M.B.)
Energy Technology Data Exchange (ETDEWEB)
Profio, A. E.; Koppel, J. U. [General Atomic Division of General Dynamics Corporation, John Jay Hopkins Laboratory for Pure and Applied Science, San Diego, CA (United States); Adamantiades, A. [Massachusetts Institute of Technology, Cambridge, MA (United States)
1965-08-15
The mean time and variance in time for neutrons from an impulse source to slow down and migrate to the energy, angle and position of observation are important quantities in many experiments. The mean time is a correction in time-of-flight measurements of neutron spectra in bulk media, and the variance limits the ultimate resolution of such experiments. These parameters are equally significant in detectors which depend on moderation, in time-of-flight experiments where low energy neutrons are provided by a moderator placed near the pulsed source, and in slowing-down-time spectrometry. Various analytical and numerical methods have been developed to calculate the space-energy-angle-time . dependence, or integrals thereof. It is shown that the time moments, Empty-Set {sup (n)} (r, {Omega}, v, t) = {integral}{sub 0}{sup {infinity}}t{sup n} Empty-Set (r, {Omega}, v, t)dt, can be calculated by repeated application of a steady state transport code. The source term for the calculation of the n{sup -tb} moment is equal to nv{sup -1} Empty-Set {sup (n-1)}. Results are presented for multiplying and non-multiplying mockups of the TRIGA reactor. Another powerful calculational method is the time-dependent Monte Carlo code. Results of a calculation of leakage flux from a thin lead slab are presented. Measurements have been made of the slowing-down time to the cadmium edge and to the 1.46-eV resonance of indium in water and in toluene. Capture gamma rays are detected by a scintillation counter. The technique requires a fairly intense source and efficient detector because of the low duty cycle (short burst width for resolution of the slowing-down time, large interpulse period for thermal neutron die-away) and the small probability for capture. (author) [French] Dans le phenomene de ralentissement et de migration des neutrons puises, amenes a l'enetgie, a l'angle et S la position d'observation, le temps moyen et la variance en temps sont des grandeurs importantes pour beaucoup d
Energy Technology Data Exchange (ETDEWEB)
Robert, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1956-12-15
The life of a neutron emitted as a fast one within a moderating medium may be divided into two parts; at first it is slowed down colliding with the nuclei of the medium; later on, as soon as its energy is of the order of the thermal agitation energy, it diffuses until captured by some nucleus. As a matter of fact, dividing the evolution of a neutron into two phases, a slowing down phase and a diffusing phase is arbitrary, since the thermal equilibrium is attained stepwise. This report is intended to examine the means of inferring the distribution of thermal neutrons from the distribution of fast neutrons on the basis of the distribution of nascent thermal neutrons and of the law of scattering. (author) [French] La vie d'un neutron emis a l'etat rapide dans un milieu moderateur comprend 2 parties: au debut il se ralentit par chocs sur les noyaux du milieu; ensuite, lorsque son energie est de l'ordre de l'energie d'agitation thermique, il diffuse jusqu'a sa capture par un noyau. La separation de l'evolution d'un neutron en deux phases, phase de ralentissement, puis phase de diffusion, est, en realite, arbitraire; un neutron doit atteindre l'equilibre thermique progressivement. L'objet de ce rapport est de voir comment on peut deduire la repartition des thermiques de la repartition des rapides connaissant la repartition des thermiques naissants et la loi de diffusion. (au0010te.
Fundamental length and relativistic length
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1988-01-01
It si noted that the introduction of fundamental length contradicts the conventional representations concerning the contraction of the longitudinal size of fast-moving objects. The use of the concept of relativistic length and the following ''elongation formula'' permits one to solve this problem
Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...
International Nuclear Information System (INIS)
Pradhan, T.
1975-01-01
The concept of fundamental length was first put forward by Heisenberg from purely dimensional reasons. From a study of the observed masses of the elementary particles known at that time, it is sumrised that this length should be of the order of magnitude 1 approximately 10 -13 cm. It was Heisenberg's belief that introduction of such a fundamental length would eliminate the divergence difficulties from relativistic quantum field theory by cutting off the high energy regions of the 'proper fields'. Since the divergence difficulties arise primarily due to infinite number of degrees of freedom, one simple remedy would be the introduction of a principle that limits these degrees of freedom by removing the effectiveness of the waves with a frequency exceeding a certain limit without destroying the relativistic invariance of the theory. The principle can be stated as follows: It is in principle impossible to invent an experiment of any kind that will permit a distintion between the positions of two particles at rest, the distance between which is below a certain limit. A more elegant way of introducing fundamental length into quantum theory is through commutation relations between two position operators. In quantum field theory such as quantum electrodynamics, it can be introduced through the commutation relation between two interpolating photon fields (vector potentials). (K.B.)
Slowing down to keep the lead in military technology
Blanken, Leo J.; Leopore, Jason J.
2011-01-01
The article of record as published may be found at http://dx.doi.org/10.1080/10242694.2010.491675 We develop a model of military technology competition among states. States can choose to introduce new military technology, mimic rivals’ level of technology, or withdraw from the contest. States can choose to implement any level of technology within their current feasible technologies. We find that states with significant technological leads should sometimes withhold new technologies...
Adjoint P1 equations solution for neutron slowing down
International Nuclear Information System (INIS)
Cardoso, Carlos Eduardo Santos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da
2002-01-01
In some applications of perturbation theory, it is necessary know the adjoint neutron flux, which is obtained by the solution of adjoint neutron diffusion equation. However, the multigroup constants used for this are weighted in only the direct neutron flux, from the solution of direct P1 equations. In this work, the adjoint P1 equations are derived by the neutron transport equation, the reversion operators rules and analogies between direct and adjoint parameters. The direct and adjoint neutron fluxes resulting from the solution of P 1 equations were used to three different weighting processes, to obtain the macrogroup macroscopic cross sections. It was found out noticeable differences among them. (author)
Estonian economic growth slows down / Olavi Grünvald
Grünvald, Olavi
2008-01-01
Ülevaade Eesti majandusliku arengu viimastest aastatest, 2007. aastal alanud majanduslangusest, mida iseloomustavad langus kinnisvaraturul, SKT kasvu aeglustumine, transiitkaubanduse vähenemine. Lisatud tabel diagramm ja graafikud
Loan Growth Slowing down in 1st 7 Months
Institute of Scientific and Technical Information of China (English)
无
2004-01-01
@@ The growth of loans significantly slowed during the first seven months of this year, which indicates the government's economic macro control measures are taking effect, the People's Bank of China (PBOC) said. By the end of July, outstanding loans of all financial institutions stood at RMB18.1 trillion (US$2.18 trillion),up 15.9% on a year-on-year basis. The growth rate compared to 23.2% registered during the same period in 2003,the central bank said.
Pollinator species richness: Are the declines slowing down?
Directory of Open Access Journals (Sweden)
Tom J. M. Van Dooren
2016-09-01
Full Text Available Changes in pollinator abundances and diversity are of major concern. A recent study inferred that pollinator species richnesses are decreasing more slowly in recent decades in several taxa and European countries. A more careful interpretation of these results reveals that this conclusion cannot be drawn and that we can only infer that declines decelerate for bees (Anthophila in the Netherlands.
Proprioceptive deafferentation slows down the processing of visual hand feedback
DEFF Research Database (Denmark)
Balslev, Daniela; Miall, R Chris; Cole, Jonathan
2007-01-01
During visually guided movements both vision and proprioception inform the brain about the position of the hand, so interaction between these two modalities is presumed. Current theories suggest that this interaction occurs by sensory information from both sources being fused into a more reliable...... proprioception facilitates the processing of visual information during motor control. Subjects used a computer mouse to move a cursor to a screen target. In 28% of the trials, pseudorandomly, the cursor was rotated or the target jumped. Reaction time for the trajectory correction in response to this perturbation......, multimodal, percept of hand location. In the literature on perception, however, there is evidence that different sensory modalities interact in the allocation of attention, so that a stimulus in one modality facilitates the processing of a stimulus in a different modality. We investigated whether...
The roots to an equation in particle slowing down theory
International Nuclear Information System (INIS)
Sjoestrand, N.G.
1979-08-01
Previous work on the roots to an equation arising in studies on anisotropic neutron scattering has been extended to include parameter values of interest for a problem put forward by M.M.R. Williams. Detailed numerical results are given. (author)
The Evolution of Computing: Slowing down? Not Yet!
CERN. Geneva
2004-01-01
Dr Sutherland will review the evolution of computing over the past decade, focusing particularly on the development of the database and middleware from client server to Internet computing. But what are the next steps from the perspective of a software company? Dr Sutherland will discuss the development of Grid as well as the future applications revolving around collaborative working, which are appearing as the next wave of computing applications.
The energy deposition of slowing down particles in heterogeneous media
International Nuclear Information System (INIS)
Prinja, A.K.; Williams, M.M.R.
1980-01-01
Energy deposition by atomic particles in adjacent semi-infinite, amorphous media is described using the forward form of the Boltzmann transport equation. A transport approximation to the scattering kernel, developed elsewhere, incorporating realistic energy transfer is employed to assess the validity of the commonly used isotropic-scattering and straight-ahead approximations. Results are presented for integral energy deposition rates due to a plane, isotropic and monoenergetic source in one half-space for a range of mass ratios between 0.1 and 5.0. Integral profiles for infinite and semi-infinite media are considered and the influence of reflection for different mass ratios is evaluated. The dissimilar scattering properties of the two media induce a discontinuity at the interface in the energy deposition rate the magnitude of which is sensitive to the source position relative to the interface. A comprehensive evaluation of the total energy deposited in the source free medium is presented for a range of mass ratios and source positions. An interesting minimum occurs for off-interface source locations as a function of the source-medium mass ratio, the position of which varies with the source position but is insensitive to the other mass ratio. As a special case, energy reflection and escape coefficients for semi-infinite media are obtained which demonstrates that the effect of a vacuum interface is insignificant for deep source locations except for large mass ratios when reflection becomes dominant. (author)
Buick, Otto; Falcon, Pat; Alexander, G.; Siegel, Edward Carl-Ludwig
2013-03-01
Einstein[Dover(03)] critical-slowing-down(CSD)[Pais, Subtle in The Lord; Life & Sci. of Albert Einstein(81)] is Siegel CyberWar denial-of-access(DOA) operations-research queuing theory/pinning/jamming/.../Read [Aikido, Aikibojitsu & Natural-Law(90)]/Aikido(!!!) phase-transition critical-phenomenon via Siegel DIGIT-Physics (Newcomb[Am.J.Math. 4,39(1881)]-{Planck[(1901)]-Einstein[(1905)])-Poincare[Calcul Probabilités(12)-p.313]-Weyl [Goett.Nachr.(14); Math.Ann.77,313 (16)]-{Bose[(24)-Einstein[(25)]-Fermi[(27)]-Dirac[(1927)]}-``Benford''[Proc.Am.Phil.Soc. 78,4,551 (38)]-Kac[Maths.Stat.-Reasoning(55)]-Raimi[Sci.Am. 221,109 (69)...]-Jech[preprint, PSU(95)]-Hill[Proc.AMS 123,3,887(95)]-Browne[NYT(8/98)]-Antonoff-Smith-Siegel[AMS Joint-Mtg.,S.-D.(02)] algebraic-inversion to yield ONLY BOSE-EINSTEIN QUANTUM-statistics (BEQS) with ZERO-digit Bose-Einstein CONDENSATION(BEC) ``INTERSECTION''-BECOME-UNION to Barabasi[PRL 876,5632(01); Rev.Mod.Phys.74,47(02)...] Network /Net/GRAPH(!!!)-physics BEC: Strutt/Rayleigh(1881)-Polya(21)-``Anderson''(58)-Siegel[J.Non-crystalline-Sol.40,453(80)
Energy Technology Data Exchange (ETDEWEB)
Möller, S., E-mail: s.moeller@fz-juelich.de
2017-03-01
Ion beam analysis is a set of precise, calibration free and non-destructive methods for determining surface-near concentrations of potentially all elements and isotopes in a single measurement. For determination of concentrations the reaction cross-section of the projectile with the targets has to be known, in general at the primary beam energy and all energies below. To reduce the experimental effort of cross-section measurements a new method is presented here. The method is based on the projectile energy reduction when passing matter of thick targets. The continuous slowing down approximation is used to determine cross-sections from a thick target at projectile energies below the primary energy by backward calculation of the measured product spectra. Results for {sup 12}C({sup 3}He,p){sup 14}N below 4.5 MeV are in rough agreement with literature data and reproduce the measured spectra. New data for reactions of {sup 3}He with {sup 13}C are acquired using the new technique. The applied approximations and further applications are discussed.
Energy Technology Data Exchange (ETDEWEB)
Bergman, A. A.; Isakov, A. I.; Kazarnovskij, M. V.; Popov, Ju. P.; Shapiro, F. L. [Fizicheskij Institut Im. P.N. Lebedeva AN SSSR, Moskva, SSSR (Russian Federation)
1965-08-15
Over the past ten years research has been going on at the P.N. Lebedev Physics Institute on the non-stationary moderation of neutrons in heavy media, the development of a method of neutron spectrometry based on the slowing-down time and the use of this method in studying the energy dependence of the cross-sections of nuclear reactions produced by neutrons with energy up to 30 keV. The authors review this work and discuss the results achieved. After a brief discussion of the theory of the non-stationary moderation and thermalization of neutrons the authors set forth the results of experimental studies of neutron moderation in graphite, iron and lead, and of neutron thermalization in lead. Using a pulsed neutron source and resonance detectors the distribution of slowing-down times was measured up to a series of fixed values for final neutron energy. The results are compared with theory, which takes into account the thermal motion of the moderator atoms; in the case of lead this thermal motion leads to a measurable spread in the slowing-down times at energies below 10 eV. The relationship between the mean velocity of neutrons in lead and the slowing-down time is measured in the subcadmium energy range and a comparison made with multigroup theory. The procedure for determining the energy dependence of neutron reaction cross-sections by slowing-down time is described and the potentialities of this method of spectrometry discussed. There follows a brief discussion of the results obtained in two fields of spectrometric measurement. Firstly, precise measurement of the relative excitation functions of the following reactions: He{sup 3}(n, p), Li{sup 6}(n, {alpha}), B{sup 10}(n, {alpha}) and N{sup 14}(n, p) - the most interesting results being the discovery of a constant negative component of the reaction cross-section and indications of the existence of an excited He{sup 4} level. Secondly, measurement of the energy dependence of averaged radiative capture cross
Length scales in glass-forming liquids and related systems: a review
International Nuclear Information System (INIS)
Karmakar, Smarajit; Dasgupta, Chandan; Sastry, Srikanth
2016-01-01
The central problem in the study of glass-forming liquids and other glassy systems is the understanding of the complex structural relaxation and rapid growth of relaxation times seen on approaching the glass transition. A central conceptual question is whether one can identify one or more growing length scale(s) associated with this behavior. Given the diversity of molecular glass-formers and a vast body of experimental, computational and theoretical work addressing glassy behavior, a number of ideas and observations pertaining to growing length scales have been presented over the past few decades, but there is as yet no consensus view on this question. In this review, we will summarize the salient results and the state of our understanding of length scales associated with dynamical slow down. After a review of slow dynamics and the glass transition, pertinent theories of the glass transition will be summarized and a survey of ideas relating to length scales in glassy systems will be presented. A number of studies have focused on the emergence of preferred packing arrangements and discussed their role in glassy dynamics. More recently, a central object of attention has been the study of spatially correlated, heterogeneous dynamics and the associated length scale, studied in computer simulations and theoretical analysis such as inhomogeneous mode coupling theory. A number of static length scales have been proposed and studied recently, such as the mosaic length scale discussed in the random first-order transition theory and the related point-to-set correlation length. We will discuss these, elaborating on key results, along with a critical appraisal of the state of the art. Finally we will discuss length scales in driven soft matter, granular fluids and amorphous solids, and give a brief description of length scales in aging systems. Possible relations of these length scales with those in glass-forming liquids will be discussed. (review article)
DEFF Research Database (Denmark)
Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P
2008-01-01
Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...
Canela, Andrés; Klatt, Peter; Blasco, María A
2007-01-01
Most somatic cells of long-lived species undergo telomere shortening throughout life. Critically short telomeres trigger loss of cell viability in tissues, which has been related to alteration of tissue function and loss of regenerative capabilities in aging and aging-related diseases. Hence, telomere length is an important biomarker for aging and can be used in the prognosis of aging diseases. These facts highlight the importance of developing methods for telomere length determination that can be employed to evaluate telomere length during the human aging process. Telomere length quantification methods have improved greatly in accuracy and sensitivity since the development of the conventional telomeric Southern blot. Here, we describe the different methodologies recently developed for telomere length quantification, as well as their potential applications for human aging studies.
Telomere length and depression
DEFF Research Database (Denmark)
Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line
2017-01-01
BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...
Anomaly in the Chain Length Dependence of n-Alkane Diffusion in ZIF-4 Metal-Organic Frameworks
Directory of Open Access Journals (Sweden)
Seungtaik Hwang
2018-03-01
Full Text Available Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n-alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n-butane was observed, followed by an increase for n-pentane, and another decrease for n-hexane. This observation was confirmed by uptake measurements with n-butane/n-pentane mixtures, which yield faster uptake of n-pentane. Further evidence is provided by the observation of overshooting effects, i.e., by transient n-pentane concentrations exceeding the (eventually attained equilibrium value. Accompanying grand canonical Monte Carlo simulations reveal, for the larger n-alkanes, significant differences between the adsorbed and gas phase molecular configurations, indicating strong confinement effects within ZIF-4, which, with increasing chain length, may be expected to give rise to configurational shifts facilitating molecular propagation at particular chain lengths.
Anomaly in the Chain Length Dependence of n-Alkane Diffusion in ZIF-4 Metal-Organic Frameworks.
Hwang, Seungtaik; Gopalan, Arun; Hovestadt, Maximilian; Piepenbreier, Frank; Chmelik, Christian; Hartmann, Martin; Snurr, Randall Q; Kärger, Jörg
2018-03-15
Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n- alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n- butane was observed, followed by an increase for n- pentane, and another decrease for n- hexane. This observation was confirmed by uptake measurements with n- butane/ n -pentane mixtures, which yield faster uptake of n- pentane. Further evidence is provided by the observation of overshooting effects, i.e., by transient n- pentane concentrations exceeding the (eventually attained) equilibrium value. Accompanying grand canonical Monte Carlo simulations reveal, for the larger n- alkanes, significant differences between the adsorbed and gas phase molecular configurations, indicating strong confinement effects within ZIF-4, which, with increasing chain length, may be expected to give rise to configurational shifts facilitating molecular propagation at particular chain lengths.
International Nuclear Information System (INIS)
Bruyere, M.; Vallee, A.; Collette, C.
1986-09-01
Extended fuel cycle length and burnup are currently offered by Framatome and Fragema in order to satisfy the needs of the utilities in terms of fuel cycle cost and of overall systems cost optimization. We intend to point out the consequences of an increased fuel cycle length and burnup on reactor safety, in order to determine whether the bounding safety analyses presented in the Safety Analysis Report are applicable and to evaluate the effect on plant licensing. This paper presents the results of this examination. The first part indicates the consequences of increased fuel cycle length and burnup on the nuclear data used in the bounding accident analyses. In the second part of this paper, the required safety reanalyses are presented and the impact on the safety margins of different fuel management strategies is examined. In addition, systems modifications which can be required are indicated
Relativistic distances, sizes, lengths
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1992-01-01
Such notion as light or retarded distance, field size, formation way, visible size of a body, relativistic or radar length and wave length of light from a moving atom are considered. The relation between these notions is cleared up, their classification is given. It is stressed that the formation way is defined by the field size of a moving particle. In the case of the electromagnetic field, longitudinal sizes increase proportionally γ 2 with growing charge velocity (γ is the Lorentz-factor). 18 refs
Zhao, Meifang; Xiang, Wenhua; Tian, Dalun; Deng, Xiangwen; Huang, Zhihong; Zhou, Xiaolu; Peng, Changhui
2013-01-01
Cunninghamia lanceolata (Lamb.) Hook. has been widely planted in subtropical China to meet increasing timber demands, leading to short-rotation practices that deplete soil nutrients. However, increased nitrogen (N) deposition offsets soil N depletion. While long-term experimental data investigating the coupled effects related to short rotation practices and increasing N deposition are scarce, applying model simulations may yield insights. In this study, the CenW3.1 model was validated and parameterized using data from pure C. lanceolata plantations. The model was then used to simulate various changes in long-term productivity. Results indicated that responses of productivity of C. lanceolata plantation to increased N deposition were more related to stand age than N addition, depending on the proportion and age of growing forests. Our results have also shown a rapid peak in growth and N dynamics. The peak is reached sooner and is higher under higher level of N deposition. Short rotation lengths had a greater effect on productivity and N dynamics than high N deposition levels. Productivity and N dynamics decreased as the rotation length decreased. Total productivity levels suggest that a 30-year rotation length maximizes productivity at the 4.9 kg N ha−1 year−1 deposition level. For a specific rotation length, higher N deposition levels resulted in greater overall ecosystem C and N storage, but this positive correlation tendency gradually slowed down with increasing N deposition levels. More pronounced differences in N deposition levels occurred as rotation length decreased. To sustain C. lanceolata plantation productivity without offsite detrimental N effects, the appropriate rotation length is about 20–30 years for N deposition levels below 50 kg N ha−1 year−1 and about 15–20 years for N deposition levels above 50 kg N ha−1 year−1. These results highlight the importance of assessing N effects on carbon management and the long-term productivity of
Pion nucleus scattering lengths
International Nuclear Information System (INIS)
Huang, W.T.; Levinson, C.A.; Banerjee, M.K.
1971-09-01
Soft pion theory and the Fubini-Furlan mass dispersion relations have been used to analyze the pion nucleon scattering lengths and obtain a value for the sigma commutator term. With this value and using the same principles, scattering lengths have been predicted for nuclei with mass number ranging from 6 to 23. Agreement with experiment is very good. For those who believe in the Gell-Mann-Levy sigma model, the evaluation of the commutator yields the value 0.26(m/sub σ//m/sub π/) 2 for the sigma nucleon coupling constant. The large dispersive corrections for the isosymmetric case implies that the basic idea behind many of the soft pion calculations, namely, slow variation of matrix elements from the soft pion limit to the physical pion mass, is not correct. 11 refs., 1 fig., 3 tabs
Gap length distributions by PEPR
International Nuclear Information System (INIS)
Warszawer, T.N.
1980-01-01
Conditions guaranteeing exponential gap length distributions are formulated and discussed. Exponential gap length distributions of bubble chamber tracks first obtained on a CRT device are presented. Distributions of resulting average gap lengths and their velocity dependence are discussed. (orig.)
Relativistic length agony continued
Directory of Open Access Journals (Sweden)
Redžić D.V.
2014-01-01
Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028
Smarandache, Florentin
2013-09-01
Let's denote by VE the speed of the Earth and byVR the speed of the rocket. Both travel in the same direction on parallel trajectories. We consider the Earth as a moving (at a constant speed VE -VR) spacecraft of almost spherical form, whose radius is r and thus the diameter 2r, and the rocket as standing still. The non-proper length of Earth's diameter, as measured by the astronaut is: L = 2 r√{ 1 -|/VE -VR|2 c2 } rocket! Also, let's assume that the astronaut is laying down in the direction of motion. Therefore, he would also shrink, or he would die!
Directory of Open Access Journals (Sweden)
P. R. Parthasarathy
2001-01-01
Full Text Available The transient solution is obtained analytically using continued fractions for a state-dependent birth-death queue in which potential customers are discouraged by the queue length. This queueing system is then compared with the well-known infinite server queueing system which has the same steady state solution as the model under consideration, whereas their transient solutions are different. A natural measure of speed of convergence of the mean number in the system to its stationarity is also computed.
Nek1 silencing slows down DNA repair and blocks DNA damage-induced cell cycle arrest.
Pelegrini, Alessandra Luíza; Moura, Dinara Jaqueline; Brenner, Bethânia Luise; Ledur, Pitia Flores; Maques, Gabriela Porto; Henriques, João Antônio Pegas; Saffi, Jenifer; Lenz, Guido
2010-09-01
Never in mitosis A (NIMA)-related kinases (Nek) are evolutionarily conserved proteins structurally related to the Aspergillus nidulans mitotic regulator NIMA. Nek1 is one of the 11 isoforms of the Neks identified in mammals. Different lines of evidence suggest the participation of Nek1 in response to DNA damage, which is also supported by the interaction of this kinase with proteins involved in DNA repair pathways and cell cycle regulation. In this report, we show that cells with Nek1 knockdown (KD) through stable RNA interference present a delay in DNA repair when treated with methyl-methanesulfonate (MMS), hydrogen peroxide (H(2)O(2)) and cisplatin (CPT). In particular, interstrand cross links induced by CPT take much longer to be resolved in Nek1 KD cells when compared to wild-type (WT) cells. In KD cells, phosphorylation of Chk1 in response to CPT was strongly reduced. While WT cells accumulate in G(2)/M after DNA damage with MMS and H(2)O(2), Nek1 KD cells do not arrest, suggesting that G(2)/M arrest induced by the DNA damage requires Nek1. Surprisingly, CPT-treated Nek1 KD cells arrest with a 4N DNA content similar to WT cells. This deregulation in cell cycle control in Nek1 KD cells leads to an increased sensitivity to genotoxic agents when compared to WT cells. These results suggest that Nek1 is involved in the beginning of the cellular response to genotoxic stress and plays an important role in preventing cell death induced by DNA damage.
Robustness of variance and autocorrelation as indicators of critical slowing down
Dakos, V.; Nes, van E.H.; Odorico, D' P.; Scheffer, M.
2012-01-01
Ecosystems close to a critical threshold lose resilience, in the sense that perturbations can more easily push them into an alternative state. Recently, it has been proposed that such loss of resilience may be detected from elevated autocorrelation and variance in the fluctuations of the state of an
For a tree time can be slowed down: Analysis of proliferation capacity of tree cells
Czech Academy of Sciences Publication Activity Database
Flanary, B. E.; Kletetschka, Günther
2005-01-01
Roč. 8, Supplement 1 (2005) ISSN 1549-1684. [Strategies for Engineered Negligible Senescence (SENS) /2./. 07.09.2005-11.09.2005, Cambridge] Institutional research plan: CEZ:AV0Z30130516 Keywords : telomers * telomerase * life span Subject RIV: EB - Genetics ; Molecular Biology
Application of calcium carbonate slows down organic amendments mineralization in reclaimed soils
Zornoza, Raúl; Faz, Ángel; Acosta, José A.; Martínez-Martínez, Silvia; Ángeles Muñoz, M.
2014-05-01
A field experiment was set up in Cartagena-La Unión Mining District, SE Spain, aimed at evaluating the short-term effects of pig slurry (PS) amendment alone and together with marble waste (MW) on organic matter mineralization, microbial activity and stabilization of heavy metals in two tailing ponds. These structures pose environmental risk owing to high metals contents, low organic matter and nutrients, and null vegetation. Carbon mineralization, exchangeable metals and microbiological properties were monitored during 67 days. The application of amendments led to a rapid decrease of exchangeable metals concentrations, except for Cu, with decreases up to 98%, 75% and 97% for Cd, Pb and Zn, respectively. The combined addition of MW+PS was the treatment with greater reduction in metals concentrations. The addition of PS caused a significant increase in respiration rates, although in MW+PS plots respiration was lower than in PS plots. The mineralised C from the pig slurry was low, approximately 25-30% and 4-12% for PS and MW+PS treatments, respectively. Soluble carbon (Csol), microbial biomass carbon (MBC) and β-galactosidase and β-glucosidase activities increased after the application of the organic amendment. However, after 3 days these parameters started a decreasing trend reaching similar values than control from approximately day 25 for Csol and MBC. The PS treatment promoted highest values in enzyme activities, which remained high upon time. Arylesterase activity increased in the MW+PS treatment. Thus, the remediation techniques used improved soil microbiological status and reduced metal availability. The combined application of PS+MW reduced the degradability of the organic compounds. Keywords: organic wastes, mine soils stabilization, carbon mineralization, microbial activity.
Critical slowing down and the gradient flow coupling in the Schroedinger functional
Energy Technology Data Exchange (ETDEWEB)
Fritzsch, Patrick; Stollenwerk, Felix [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Ramos, Alberto [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2013-11-15
We study the sensitivity of the gradient flow coupling to sectors of different topological charge and its implications in practical situations. Furthermore, we investigate an alternative definition of the running coupling that is expected to be less sensitive to the problems of the HMC algorithm to efficiently sample all topological sectors.
Oligotrophication and Metabolic Slowing-Down of a NW Mediterranean Coastal Ecosystem
Agusti, Susana; Martinez Ayala, Juan; Regaudie-de-Gioux, Aurore; Duarte, Carlos M.
2017-01-01
temperate area, there were seasonal patterns associated to changes in the broad temperature range (12.0–28.4°C), with a primary phytoplankton bloom in late winter and a secondary one in the fall. Community respiration (R) rates peaked during summers
He, Monica M
2016-04-01
The relationship between short-term macroeconomic growth and temporary mortality increases remains strongest for motor vehicle (MV) crashes. In this paper, I investigate the mechanisms that explain falling MV fatality rates during the recent Great Recession. Using U.S. state-level panel data from 2003 to 2013, I first estimate the relationship between unemployment and MV fatality rate and then decompose it into risk and exposure factors for different types of MV crashes. Results reveal a significant 2.9 percent decrease in MV fatality rate for each percentage point increase in unemployment rate. This relationship is almost entirely explained by changes in the risk of driving rather than exposure to the amount of driving and is particularly robust for crashes involving large commercial trucks, multiple vehicles, and speeding cars. These findings provide evidence suggesting traffic patterns directly related to economic activity lead to higher risk of MV fatality rates when the economy improves. Copyright © 2016 Elsevier Ltd. All rights reserved.
49 CFR 392.11 - Railroad grade crossings; slowing down required.
2010-10-01
... MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS DRIVING OF COMMERCIAL MOTOR VEHICLES Driving of Commercial Motor Vehicles § 392.11 Railroad grade..., upon approaching a railroad grade crossing, be driven at a rate of speed which will permit said...
Very low velocity ion slowing down in binary ionic mixtures: Charge- and mass-asymmetry effects
Directory of Open Access Journals (Sweden)
Patrice Fromy
2010-10-01
Full Text Available A binary ionic mixture (BIM in dense and hot plasmas of specific concern for inertial confinement fusion and white dwarf crust is considered as a target for incoming light ions with a velocity smaller than the thermal electron one. The given target stopping power, mostly BIM monitored, is specifically studied in terms of charge and mass asymmetry in its ionic component. The classical plasma target is worked out within a dielectric framework, and scanned with respect to density, temperature, and BIM composition.
Treatment of pregnant rats with oleoyl-estrone slows down pup fat deposition after weaning
Directory of Open Access Journals (Sweden)
Vilà Ruth
2008-06-01
Full Text Available Abstract Background In rats, oral oleoyl-estrone (OE decreases food intake and body lipid content. The aim of this study was to determine whether OE treatment affects the energy metabolism of pregnant rats and eventually, of their pups; i.e. changes in normal growth patterns and the onset of obesity after weaning. Methods Pregnant Wistar rats were treated with daily intragastric gavages of OE in 0.2 ml sunflower oil from days 11 to 21 of pregnancy (i.e. 10 nmol oleoyl-estrone/g/day. Control animals received only the vehicle. Plasma and hormone metabolites were determined together with variations in cellularity of adipose tissue. Results Treatment decreased food intake and lowered weight gain during late pregnancy, mainly because of reduced adipose tissue accumulation in different sites. OE-treated pregnant rats' metabolic pattern after delivery was similar to that of controls. Neonates from OE-treated rats weighed the same as those from controls. They also maintained the same growth rate up to weaning, but pups from OE-treated rats slowed their growth rate afterwards, despite only limited differences in metabolite concentrations. Conclusion The OE influences on pup growth can be partially buffered by maternal lipid mobilization during the second half of pregnancy. This maternal metabolic "imprinting" may condition the eventual accumulation of adipose tissue after weaning, and its effects can affect the regulation of body weight up to adulthood.
Major mechanisms contributing to the macrofauna-mediated slow down of litter decomposition
Czech Academy of Sciences Publication Activity Database
Frouz, Jan; Špaldoňová, A.; Lhotáková, Z.; Cajthaml, T.
2015-01-01
Roč. 91, December (2015), s. 23-31 ISSN 0038-0717 Grant - others:GA ČR(CZ) GAP504/12/1288 Program:GA Institutional support: RVO:60077344 Keywords : alkalinization * Bibio * CN ratio * litter decomposition * mineralization * pyrolysis Subject RIV: DF - Soil Science Impact factor: 4.152, year: 2015
Analysis of a Scenario for Chaotic Quantal Slowing Down of Inspiration
2013-01-01
On exposure to opiates, preparations from rat brain stems have been observed to continue to produce regular expiratory signals, but to fail to produce some inspiratory signals. The numbers of expirations between two successive inspirations form an apparently random sequence. Here, we propose an explanation based on the qualitative theory of dynamical systems. A relatively simple scenario for the dynamics of interaction between the generators of expiratory and inspiratory signals produces pseudo-random behaviour of the type observed. PMID:24040967
Rhythm perception: speeding up or slowing down affects different subcomponents of the ERP P3 complex
Jongsma, M.A.; Meeuwissen, Esther; Vos, Piet G.; Maes, Roald
2007-01-01
The aim of this study was to investigate, by measuring the event related potential (ERP) P3 complex, whether the perception of small accelerations differs from that of small decelerations. Participants had to decide whether the last beat of a short sequence was presented ‘too early’ or ‘too late’.
Slowing down after a mild traumatic brain injury: a strategy to improve cognitive task performance?
Ozen, Lana J; Fernandes, Myra A
2012-01-01
Long-term persistent attention and memory difficulties following a mild traumatic brain injury (TBI) often go undetected on standard neuropsychological tests, despite complaints by mild TBI individuals. We conducted a visual Repetition Detection working memory task to digits, in which we manipulated task difficulty by increasing cognitive load, to identify subtle deficits long after a mild TBI. Twenty-six undergraduate students with a self-report of one mild TBI, which occurred at least 6 months prior, and 31 non-head-injured controls took part in the study. Participants were not informed until study completion that the study's purpose was to examine cognitive changes following a mild TBI, to reduce the influence of "diagnosis threat" on performance. Neuropsychological tasks did not differentiate the groups, though mild TBI participants reported higher state anxiety levels. On our working memory task, the mild TBI group took significantly longer to accurately detect repeated targets on our task, suggesting that slowed information processing is a long-term consequence of mild TBI. Accuracy was comparable in the low-load condition and, unexpectedly, mild TBI performance surpassed that of controls in the high-load condition. Temporal analysis of target identification suggested a strategy difference between groups: mild TBI participants made a significantly greater number of accurate responses following the target's offset, and significantly fewer erroneous distracter responses prior to target onset, compared with controls. Results suggest that long after a mild TBI, high-functioning young adults invoke a strategy of delaying their identification of targets in order to maintain, and facilitate, accuracy on cognitively demanding tasks. © The Author 2011. Published by Oxford University Press. All rights reserved.
The automatic visual simulation of words: A memory reactivated mask slows down conceptual access.
Rey, Amandine E; Riou, Benoit; Vallet, Guillaume T; Versace, Rémy
2017-03-01
How do we represent the meaning of words? The present study assesses whether access to conceptual knowledge requires the reenactment of the sensory components of a concept. The reenactment-that is, simulation-was tested in a word categorisation task using an innovative masking paradigm. We hypothesised that a meaningless reactivated visual mask should interfere with the simulation of the visual dimension of concrete words. This assumption was tested in a paradigm in which participants were not aware of the link between the visual mask and the words to be processed. In the first phase, participants created a tone-visual mask or tone-control stimulus association. In the test phase, they categorised words that were presented with 1 of the tones. Results showed that words were processed more slowly when they were presented with the reactivated mask. This interference effect was only correlated with and explained by the value of the visual perceptual strength of the words (i.e., our experience with the visual dimensions associated with concepts) and not with other characteristics. We interpret these findings in terms of word access, which may involve the simulation of sensory features associated with the concept, even if participants were not explicitly required to access visual properties. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Hak, L.; Houdijk, J.H.P.; Steenbrink, F.; van der Wurff, P.; Beek, P.J.; van Dieen, J.H.
2012-01-01
It has frequently been proposed that lowering walking speed is a strategy to enhance gait stability and to decrease the probability of falling. However, previous studies have not been able to establish a clear relation between walking speed and gait stability. We investigated whether people do
Data from ‘Critical Slowing Down as a Personalized Early Warning Signal for Depression’
Directory of Open Access Journals (Sweden)
Jolanda J Kossakowski
2017-02-01
Full Text Available We present a dataset of a single (N = 1 participant diagnosed with major depressive disorder, who completed 1478 measurements over the course of 239 consecutive days in 2012 and 2013. The experiment included a double-blind phase in which the dosage of anti-depressant medication was gradually reduced. The entire study looked at momentary affective states in daily life before, during, and after the double-blind phase. The items, which were asked ten times a day, cover topics like mood, physical condition and social contacts. Also, depressive symptoms were measured on a weekly basis using the Symptom Checklist Revised (SCL-90-R. The data are suitable for various time-series analyses and studies in complex dynamical systems.
Get a license, buckle up, and slow down: risky driving patterns among saudis.
El Bcheraoui, Charbel; Basulaiman, Mohammed; Tuffaha, Marwa; Daoud, Farah; Robinson, Margaret; Jaber, Sara; Mikhitarian, Sarah; Wilson, Shelley; Memish, Ziad A; Al Saeedi, Mohammad; Almazroa, Mohammad A; Mokdad, Ali H
2015-01-01
Road traffic injuries are the largest cause of loss of disability-adjusted life years for men and women of all ages in the Kingdom of Saudi Arabia, but data on driving habits there are lacking. To inform policymakers on drivers' abilities and driving habits, we analyzed data from the Saudi Health Interview Survey 2013. We surveyed a representative sample of 5,235 Saudi males aged 15 years or older on wearing seat belts, exceeding speed limits, and using a handheld cell phone while driving. Male and female respondents were surveyed on wearing seat belts as passengers. Among Saudi males, 71.7% reported having had a driver's license, but more than 43% of unlicensed males drove a vehicle. Among drivers, 86.1% engaged in at least one risky behavior while driving. Older and unlicensed drivers were more likely to take risks while driving. This risk decreased among the more educated, current smokers, and those who are physically active. Up to 94.9% and 98.5% of respondents reported not wearing a seat belt in the front and the back passenger seats, respectively. The high burden of road traffic injuries in the Kingdom is not surprising given our findings. Our study calls for aggressive monitoring and enforcement of traffic laws. Awareness and proper education for drivers and their families should be developed jointly by the Ministries of Health, Interior Affairs, and Education and provided through their channels.
Atorvastatin slows down the deterioration of inner ear function with age in mice
Czech Academy of Sciences Publication Activity Database
Syka, Josef; Ouda, Ladislav; Nachtigal, P.; Solichová, D.; Semecký, V.
2007-01-01
Roč. 411, č. 2 (2007), s. 112-116 ISSN 0304-3940 R&D Projects: GA ČR GA309/04/1074; GA MZd NR8113; GA MŠk LC554; GA ČR GP304/03/P049 Institutional research plan: CEZ:AV0Z50390512 Keywords : Statins * Presbycusis * Distortion product otoacoustic emission Subject RIV: FH - Neurology Impact factor: 2.085, year: 2007
Critical slowing down and the gradient flow coupling in the Schroedinger functional
International Nuclear Information System (INIS)
Fritzsch, Patrick; Stollenwerk, Felix; Ramos, Alberto
2013-11-01
We study the sensitivity of the gradient flow coupling to sectors of different topological charge and its implications in practical situations. Furthermore, we investigate an alternative definition of the running coupling that is expected to be less sensitive to the problems of the HMC algorithm to efficiently sample all topological sectors.
NMR line broadening in solids by slowing down of spin fluctuations
International Nuclear Information System (INIS)
Mehring, M.; Sinning, G.; Pines, A.; California Univ., Berkeley
1976-01-01
The 109 Ag nuclear magnetic resonance line in a sample of polycrystalline AgF is observed to broaden substantially when the 19 F spins are irradiated near the magic angle in their rotating frame. This is due to the reduction of 19 F- 19 F dipolar coupling, which normally causes fluctuations in the 19 F- 109 Ag interactions (Abragam and Winter), inducing an exchange narrowing analogous to classical motional narrowing. The 109 Ag linewidths obtained over the entire motional range at different 19 F frequencies are compared with those calculated exactly from the ratio of second to fourth moment. (orig.) [de
DEFF Research Database (Denmark)
Dalgas, Ulrik; Stenager, Egon
2012-01-01
studies evaluating the effects on clinical outcome measures, (2) cross-sectional studies evaluating the relationship between fitness status and MRI findings, (3) cross-sectional and longitudinal studies evaluating the relationship between exercise/physical activity and disability/relapse rate and, finally......, (4) longitudinal exercise studies applying the experimental autoimmune encephalomyelitis (EAE) animal model of MS. Data from intervention studies evaluating disease progression by clinical measures (1) do not support a disease-modifying effect of exercise; however, MRI data (2), patient-reported data...... (3) and data from the EAE model (4) indicate a possible disease-modifying effect of exercise, but the strength of the evidence limits definite conclusions. It was concluded that some evidence supports the possibility of a disease-modifying potential of exercise (or physical activity) in MS patients...
Energy Technology Data Exchange (ETDEWEB)
Kratzsch, H [Technische Univ. Berlin (Germany). Inst. fuer Bergbauwissenschaften
1994-10-01
Today's widely spread view that rapid deformation will enhance damage to buildings was not underpinned by major reasons of soil mechanics and building physics. It is true that a shower rise in deformation will favour grain relocation in the foundation soil and, as a result, will diminish the soil pressure on cellar walls or on pipes embedded in the ground in the pressurized zone and will reduce the floor-level pressure peak in the bending zone by subsequent settling of foundation components. However, damage will not be found to differ in degree if deformation had lasted for 50 days ([nu][sub A]=8 m/d) or 200 days ([nu][sub A]=2 m/d). It may be assumed to be hardly relevant for the degree of damage sustained if bending, shifting (friction), tearing (shearing) or pressing of a building part (e.g. wall, ceiling, pillar), or of a building element (e.g. brick, mortar injoints) or of a building composed of all these parts rise to their final levels within a period of 50 or 200 days. (orig./MSK)
Carvalheiro, L.G.; Kunin, W.E.; Keil, P.; Aguirre-Gutiérrez, J.; Ellis, W.N.; Fox, R.; Groom, Q.; Hennekens, S.; Van Landuyt, W.; Maes, D.; Van de Meutter, F.; Michez, D.; Rasmont, P.; Ode, B.; Potts, S.G.; Reemer, M.; Roberts, S.P.M.; Schaminée, J.; WallisDeVries, M.F.; Biesmeijer, J.C.
2013-01-01
Concern about biodiversity loss has led to increased public investment in conservation. Whereas there is a widespread perception that such initiatives have been unsuccessful, there are few quantitative tests of this perception. Here, we evaluate whether rates of biodiversity change have altered in
Possible options to slow down the advancement rate of Tarbela delta.
Habib-Ur-Rehman; Rehman, Mirza Abdul; Naeem, Usman Ali; Hashmi, Hashim Nisar; Shakir, Abdul Sattar
2017-12-22
The pivot point of delta in Tarbela dam has reached at about 10.6 km from the dam face which may result in blocking of tunnels. Tarbela delta was modeled from 1979 to 2060 using hec-6 model. Initially, the model was calibrated for year 1999 and validated for years 2000, 2001, 2002, and 2006 by involving the data of sediment concentration, reservoir cross sections (73 range lines), elevation-area capacity curves, and inflows and outflows from the reservoir. Then, the model was used to generate future scenarios, i.e., run-1, run-2, and run-3 with pool levels; 428, 442, and 457 m, respectively, till 2060. Results of run-1 and run-2 showed advancement to choke the tunnels by 2010 and 2030, respectively. Finally, in run-3, the advancement was further delayed showing that tunnels 1 and 2 will be choked by year 2050 and pivot point will reach at 6.4 km from the dam face.
Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan
International Nuclear Information System (INIS)
Gu, X N; Zheng, Y F; Lan, Q X; Cheng, Y; Xi, T F; Zhang, Z X; Zhang, D Y
2009-01-01
The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10 5 for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.
Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan
Energy Technology Data Exchange (ETDEWEB)
Gu, X N; Zheng, Y F; Lan, Q X [State Key Laboratory for Turbulence and Complex System and College of Engineering, Peking University, Beijing 100871 (China); Cheng, Y; Xi, T F [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Z X [Biomedical Engineering Research Center, Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Zhang, D Y, E-mail: gxn139888@pku.edu.c, E-mail: yfzheng@pku.edu.c, E-mail: 8lanqiuxiang@163.co, E-mail: chengyan@pku.edu.c, E-mail: top5460@163.co, E-mail: xitingfei@tom.co, E-mail: zhangdeyuan@lifetechmed.co [Lifetech Scientific (Shenzhen) Co. Ltd, Hi-Tech Park, Shenzhen 518000 (China)
2009-08-15
The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10{sup 5} for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.
Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan.
Gu, X N; Zheng, Y F; Lan, Q X; Cheng, Y; Zhang, Z X; Xi, T F; Zhang, D Y
2009-08-01
The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10(5) for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.
Directory of Open Access Journals (Sweden)
Eiko I Fried
2015-03-01
Full Text Available Major Depression (MD is a highly heterogeneous diagnostic category. Diverse symptoms such as sad mood, anhedonia, and fatigue are routinely added to an unweighted sum-score, and cutoffs are used to distinguish between depressed participants and healthy controls. Researchers then investigate outcome variables like MD risk factors, biomarkers, and treatment response in such samples. These practices presuppose that (1 depression is a discrete condition, and that (2 symptoms are interchangeable indicators of this latent disorder. Here I review these two assumptions, elucidate their historical roots, show how deeply engrained they are in psychological and psychiatric research, and document that they contrast with evidence. Depression is not a consistent syndrome with clearly demarcated boundaries, and depression symptoms are not interchangeable indicators of an underlying disorder. Current research practices lump individuals with very different problems into one category, which has contributed to the remarkably slow progress in key research domains such as the development of efficacious antidepressants or the identification of biomarkers for depression.The recently proposed network framework offers an alternative to the problematic assumptions. MD is not understood as a distinct condition, but as heterogeneous symptom cluster that substantially overlaps with other syndromes such as anxiety disorders. MD is not framed as an underlying disease with a number of equivalent indicators, but as a network of symptoms that have direct causal influence on each other: insomnia can cause fatigue which then triggers concentration and psychomotor problems. This approach offers new opportunities for constructing an empirically based classification system and has broad implications for future research.
Directory of Open Access Journals (Sweden)
Adrian-Ducu, MATEI
2014-11-01
Full Text Available The article highlights some sources of inequalities in a globalized world which does not only generate positive impact. In the event it is mismanaged, globalization can give life to a mechanism facilitating tax evasion and, in the same time, ensuring for a small group of individuals, a power position not only when negotiating inside a company but also across the political life of a society. Moreover, the most important traits of corruption and underground economy are marked out in relation to the deepening of social inequality in Romania. These negative phenomena are also present due to the malfunctioning of the market, strengthened monopolies, hindered competition and excessive use of asymmetric information. In the current context of an economic and financial crisis, one much linked to trust, phenomena such as corruption, underground economy and tax evasion have become omnipresent, hot topics in both Romania and Europe. This is how the economy is taken over and significant resources of the public budget are missed by the state. The consequences are severe and can lead to incapacity to ensure a decent standard of living and ultimately social peace. A continuous attempt to curb these phenomena could and should be a priority and a method to settle the public financial equilibrium in Europe and in Romania in particular.
Magnetic field protects plants against high light by slowing down production of singlet oxygen
Czech Academy of Sciences Publication Activity Database
Hakala-Yatkin, M.; Sarvikas, P.; Paturi, P.; Mattila, H.; Tyystjärvi, T.; Nedbal, Ladislav; Tyystjärvi, E.
2011-01-01
Roč. 142, č. 1 (2011), s. 26-34 ISSN 0031-9317 Institutional research plan: CEZ:AV0Z60870520 Keywords : photosynthetic reaction-center * Photosystem-II * alpha-tocopherol * environmental-stress * manganese complex * evolving complex * oxidative stress Subject RIV: EH - Ecology, Behaviour Impact factor: 3.112, year: 2011
Slow down or race to halt: towards managing complexity of real-time energy management decisions
Petters, Stefan M.; Awan, Muhammad Ali
2010-01-01
Existing work in the context of energy management for real-time systems often ignores the substantial cost of making DVFS and sleep state decisions in terms of time and energy and/or assume very simple models. Within this paper we attempt to explore the parameter space for such decisions and possible constraints faced.
Moving Clocks Do Not Always Appear to Slow down: Don't Neglect the Doppler Effect
Wang, Frank
2013-01-01
In popular accounts of the time dilation effect in Einstein's special relativity, one often encounters the statement that moving clocks run slow. For instance, in the acclaimed PBS program "NOVA," Professor Brian Greene says, "[I]f I walk toward that guy... he'll perceive my watch ticking slower." Also in his earlier piece for The New York Times,…
Does Physiological Stress Slow Down Wound Healing in Patients With Diabetes?
Razjouyan, Javad; Grewal, Gurtej Singh; Talal, Talal K; Armstrong, David G; Mills, Joseph L; Najafi, Bijan
2017-07-01
Poor healing is an important contributing factor to amputation among patients with diabetic foot ulcers (DFUs). Physiological stress may slow wound healing and increase susceptibility to infection. The objective was to examine the association between heart rate variability (HRV) as an indicator of physiological stress response and healing speed (Heal Speed ) among outpatients with active DFUs. Ambulatory patients with diabetes with DFUs (n = 25, age: 59.3 ± 8.3 years) were recruited. HRV during pre-wound dressing was measured using a wearable sensor attached to participants' chest. HRVs were quantified in both time and frequency domains to assess physiological stress response and vagal tone (relaxation). Change in wound size between two consecutive visits was used to estimate Heal Speed . Participants were then categorized into slow healing and fast healing groups. Between the two groups, comparisons were performed for demographic, clinical, and HRV derived parameters. Associations between different descriptors of HRV and Heal Speed were also assessed. Heal Speed was significantly correlated with both vagal tone ( r = -.705, P = .001) and stress response ( r = .713, P = .001) extracted from frequency domain. No between-group differences were observed except those from HRV-derived parameters. Models based on HRVs were the highest predictors of slow/fast Heal Speed (AUC > 0.90), while models based on demographic and clinical information had poor classification performance (AUC = 0.44). This study confirms an association between stress/vagal tone and wound healing in patients with DFUs. In particular, it highlights the importance of vagal tone (relaxation) in expediting wound healing. It also demonstrates the feasibility of assessing physiological stress responses using wearable technology in outpatient clinic during routine clinic visits.
Herbivory and competition slow down invasion of a tall grass along a productivity gradient
Kuijper, DPJ; Nijhoff, DJ; Bakker, JP
2004-01-01
Competition models including competition for light predict that small plant species preferred by herbivores will be outshaded by taller unpreferred plant species with increasing productivity. When the tall plant species is little grazed by the herbivores, it can easily invade and dominate short
Motor fatigue measurement by distance-induced slow down of walking speed in multiple sclerosis.
Directory of Open Access Journals (Sweden)
Rémy Phan-Ba
Full Text Available BACKGROUND AND RATIONALE: Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS. We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW, a corrected version of the T25FW with dynamic start (T25FW(+, the timed 100-meter walk (T100MW and the timed 500-meter walk (T500MW. METHODS: Thirty controls and 81 pMS performed the 4 walking tests in a single study visit. RESULTS: The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW(+ provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI was significantly lower only in pMS with EDSS 4.0-6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤ 4000 m. CONCLUSION: The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course.
What's the Rush?: Slowing down Our "Hurried" Approach to Infant and Toddler Development
Bonnett, Tina
2012-01-01
What high expectations people place on their infants and toddlers who are just beginning to understand this great big world and all of its complexities! In an attempt to ensure that growth and learning occur, the fundamental needs of infants and toddlers are often pushed aside as people rush the young child to achieve the next developmental…
Measurement of the thickness and homogeneity of thin foils by slowing down alpha particles
International Nuclear Information System (INIS)
Bimbot, R.; Della Negra, S.; Deprun, C.; Gardes, D.; Rivet, M.F.
1979-01-01
The energy loss of 8.785 MeV α particles passing through a thin foil is used to measure the foil thickness. The measurement is performed in various points of the target, the abscissa and ordinate of which are set with precision from the outside of the chamber. This gives a thickness map of the target. The working up of the data, and the use of energy loss tables are made in a standard way. The absolute uncertainty is of some percent for 100 μg/cm 2 foils. The technique has been refined to reach the same precision for 10 μg/cm 2 targets [fr
When to slow down: elk residency rates on a heterogeneous landscape
Dean P. Anderson; James D. Forester; Monica G. Turner
2008-01-01
It remains unclear if patterns of habitat use are driven by animals moving to and increasing residency time in selected areas, or by animals simply returning frequently to selected areas. We studied a population of North American elk (Cervus elaphus) in the Chequamegon National Forest, Wisconsin, to examine how spatial and temporal factors influence...
Heilig, G.K.
1997-01-01
This paper is a provocative collection of arguments that came to the author's mind when reading through some of the literature on sustainable development. Similar to rather general sociological theories, these sustainability concepts - which are rooted in biological observations and theories of non-human biosphere - describe elements of a universal development philosophy. But they fail to take into account some of the most basic characteristics of how human societies and economics function a...
Does length or neighborhood size cause the word length effect?
Jalbert, Annie; Neath, Ian; Surprenant, Aimée M
2011-10-01
Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.
Keeping disease at arm's length
DEFF Research Database (Denmark)
Lassen, Aske Juul
2015-01-01
active ageing change everyday life with chronic disease, and how do older people combine an active life with a range of chronic diseases? The participants in the study use activities to keep their diseases at arm’s length, and this distancing of disease at the same time enables them to engage in social...... and physical activities at the activity centre. In this way, keeping disease at arm’s length is analysed as an ambiguous health strategy. The article shows the importance of looking into how active ageing is practised, as active ageing seems to work well in the everyday life of the older people by not giving...... emphasis to disease. The article is based on ethnographic fieldwork and uses vignettes of four participants to show how they each keep diseases at arm’s length....
Continuously variable focal length lens
Adams, Bernhard W; Chollet, Matthieu C
2013-12-17
A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.
CEBAF Upgrade Bunch Length Measurements
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Mahmoud [Old Dominion Univ., Norfolk, VA (United States)
2016-05-01
Many accelerators use short electron bunches and measuring the bunch length is important for efficient operations. CEBAF needs a suitable bunch length because bunches that are too long will result in beam interruption to the halls due to excessive energy spread and beam loss. In this work, bunch length is measured by invasive and non-invasive techniques at different beam energies. Two new measurement techniques have been commissioned; a harmonic cavity showed good results compared to expectations from simulation, and a real time interferometer is commissioned and first checkouts were performed. Three other techniques were used for measurements and comparison purposes without modifying the old procedures. Two of them can be used when the beam is not compressed longitudinally while the other one, the synchrotron light monitor, can be used with compressed or uncompressed beam.
Kondo length in bosonic lattices
Giuliano, Domenico; Sodano, Pasquale; Trombettoni, Andrea
2017-09-01
Motivated by the fact that the low-energy properties of the Kondo model can be effectively simulated in spin chains, we study the realization of the effect with bond impurities in ultracold bosonic lattices at half filling. After presenting a discussion of the effective theory and of the mapping of the bosonic chain onto a lattice spin Hamiltonian, we provide estimates for the Kondo length as a function of the parameters of the bosonic model. We point out that the Kondo length can be extracted from the integrated real-space correlation functions, which are experimentally accessible quantities in experiments with cold atoms.
Continuous lengths of oxide superconductors
Kroeger, Donald M.; List, III, Frederick A.
2000-01-01
A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.
Summary of neutron scattering lengths
International Nuclear Information System (INIS)
Koester, L.
1981-12-01
All available neutron-nuclei scattering lengths are collected together with their error bars in a uniform way. Bound scattering lengths are given for the elements, the isotopes, and the various spin-states. They are discussed in the sense of their use as basic parameters for many investigations in the field of nuclear and solid state physics. The data bank is available on magnetic tape, too. Recommended values and a map of these data serve for an uncomplicated use of these quantities. (orig.)
Overview of bunch length measurements
International Nuclear Information System (INIS)
Lumpkin, A. H.
1999-01-01
An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed
Diet, nutrition and telomere length.
Paul, Ligi
2011-10-01
The ends of human chromosomes are protected by DNA-protein complexes termed telomeres, which prevent the chromosomes from fusing with each other and from being recognized as a double-strand break by DNA repair proteins. Due to the incomplete replication of linear chromosomes by DNA polymerase, telomeric DNA shortens with repeated cell divisions until the telomeres reach a critical length, at which point the cells enter senescence. Telomere length is an indicator of biological aging, and dysfunction of telomeres is linked to age-related pathologies like cardiovascular disease, Parkinson disease, Alzheimer disease and cancer. Telomere length has been shown to be positively associated with nutritional status in human and animal studies. Various nutrients influence telomere length potentially through mechanisms that reflect their role in cellular functions including inflammation, oxidative stress, DNA integrity, DNA methylation and activity of telomerase, the enzyme that adds the telomeric repeats to the ends of the newly synthesized DNA. Copyright © 2011 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Ben Ruktantichoke
2011-06-01
Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.
Finite length Taylor Couette flow
Streett, C. L.; Hussaini, M. Y.
1987-01-01
Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.
Directory of Open Access Journals (Sweden)
Eric Costello
2011-01-01
Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.
Minimal Length, Measurability and Gravity
Directory of Open Access Journals (Sweden)
Alexander Shalyt-Margolin
2016-03-01
Full Text Available The present work is a continuation of the previous papers written by the author on the subject. In terms of the measurability (or measurable quantities notion introduced in a minimal length theory, first the consideration is given to a quantum theory in the momentum representation. The same terms are used to consider the Markov gravity model that here illustrates the general approach to studies of gravity in terms of measurable quantities.
International Nuclear Information System (INIS)
Volkov, M.K.; Osipov, A.A.
1983-01-01
The msub(π)asub(0)sup(1/2)=0.1, msub(π)asub(0)sup(3/2)=-0.1, msub(π)asub(0)sup((-))=0.07, msub(π)sup(3)asub(1)sup(1/2)=0.018, msub(π)sup(3)asub(1)aup(3/2)=0.002, msub(π)sup(3)asub(1)sup((-))=0.0044, msub(π)sup(5)asub(2)sup(1/2)=2.4x10sup(-4) and msub(π)sup(5)asub(2)sup(3/2)=-1.2x10sup(-4) scattering lengths are calculated in the framework of the composite meson model which is based on four-quark interaction. The decay form factors of (rho, epsilon, S*) → 2π, (K tilde, K*) → Kπ are used. The q 2 -terms of the quark box diagrams are taken into account. It is shown that the q 2 -terms of the box diagrams give the main contribution to the s-wave scattering lengths. The diagrams with the intermediate vector mesons begin to play the essential role at calculation of the p- and d-wave scattering lengths
International Nuclear Information System (INIS)
Cacuci, D.G.
1987-01-01
A companion paper has presented a Generalized Age-Theory expression for the scalar flux PSI 0 /sup G/(x,u) due to a plane isotropic source emitting neutrons in an infinite medium with cross sections that are constant in energy. The range of validity for this Generalized Age-Theory expression has also been determined as p = x/(2u) ≤ R(A), where R(A), the range of validity, is a function of the scatterer's mass. The purpose of this paper is to present the expression for the scalar flux Psi 0 /sup G/(x,u) in the complementary region in phase-space, i.e., where p > R(A)
Energy Technology Data Exchange (ETDEWEB)
Svenningsen, Hanne [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); Department of Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K (Denmark); Henriksen, Trine [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark); Prieme, Anders [Department of Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K (Denmark); Johnsen, Anders R., E-mail: arj@geus.dk [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Oster Voldgade 10, DK-1350 Copenhagen K (Denmark)
2011-06-15
Effects of the common antibacterial agent triclosan on microbial communities and degradation of domestic xenobiotics were studied in simulated sewage-drain-field soil. Cultivable microbial populations decreased 22-fold in the presence of 4 mg kg{sup -1} of triclosan, and triclosan-resistant Pseudomonas strains were strongly enriched. Exposure to triclosan also changed the general metabolic profile (Ecoplate substrate profiling) and the general profile (T-RFLP) of the microbial community. Triclosan degradation was slow at all concentrations tested (0.33-81 mg kg{sup -1}) during 50-days of incubation. Mineralization experiments ({sup 14}C-tracers) and chemical analyses (LC-MS/MS) showed that the persistence of a linear alkylbenzene sulfonate (LAS) and a common analgesic (ibuprofen) increased with increasing triclosan concentrations (0.16-100 mg kg{sup -1}). The largest effect was seen for LAS mineralization which was severely reduced by 0.16 mg kg{sup -1} of triclosan. Our findings indicate that environmentally realistic concentrations of triclosan may affect the efficiency of biodegradation in percolation systems. - Highlights: > Triclosan may enter the soil environment through sewage. > Triclosan impacts the microbial community in sewage-drain-field soil. > Triclosan-resistant pseudomonads are strongly enriched. > Degradation of co-occurring LAS and ibuprofen is reduced. - Environmentally realistic triclosan concentrations in percolation systems may reduce the biodegradation of other xenobiotics and select for triclosan-resistant bacteria.
International Nuclear Information System (INIS)
Svenningsen, Hanne; Henriksen, Trine; Prieme, Anders; Johnsen, Anders R.
2011-01-01
Effects of the common antibacterial agent triclosan on microbial communities and degradation of domestic xenobiotics were studied in simulated sewage-drain-field soil. Cultivable microbial populations decreased 22-fold in the presence of 4 mg kg -1 of triclosan, and triclosan-resistant Pseudomonas strains were strongly enriched. Exposure to triclosan also changed the general metabolic profile (Ecoplate substrate profiling) and the general profile (T-RFLP) of the microbial community. Triclosan degradation was slow at all concentrations tested (0.33-81 mg kg -1 ) during 50-days of incubation. Mineralization experiments ( 14 C-tracers) and chemical analyses (LC-MS/MS) showed that the persistence of a linear alkylbenzene sulfonate (LAS) and a common analgesic (ibuprofen) increased with increasing triclosan concentrations (0.16-100 mg kg -1 ). The largest effect was seen for LAS mineralization which was severely reduced by 0.16 mg kg -1 of triclosan. Our findings indicate that environmentally realistic concentrations of triclosan may affect the efficiency of biodegradation in percolation systems. - Highlights: → Triclosan may enter the soil environment through sewage. → Triclosan impacts the microbial community in sewage-drain-field soil. → Triclosan-resistant pseudomonads are strongly enriched. → Degradation of co-occurring LAS and ibuprofen is reduced. - Environmentally realistic triclosan concentrations in percolation systems may reduce the biodegradation of other xenobiotics and select for triclosan-resistant bacteria.
Energy Technology Data Exchange (ETDEWEB)
Cardoso, Carlos Eduardo Santos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear
2002-07-01
In some applications of perturbation theory, it is necessary know the adjoint neutron flux, which is obtained by the solution of adjoint neutron diffusion equation. However, the multigroup constants used for this are weighted in only the direct neutron flux, from the solution of direct P1 equations. In this work, the adjoint P1 equations are derived by the neutron transport equation, the reversion operators rules and analogies between direct and adjoint parameters. The direct and adjoint neutron fluxes resulting from the solution of P{sub 1} equations were used to three different weighting processes, to obtain the macrogroup macroscopic cross sections. It was found out noticeable differences among them. (author)
Think Local-Act Local: Is It Time to Slow Down the Accelerated Move to Global Marketing?
Schuiling, Isabelle
2001-01-01
In view of the accelerated move of great corporations towards global marketing, the strategic changes of such companies raise interesting questions. Is marketing globalization reaching its limits after years of implementation? Is it time for companies to rethink their strategies and move back, like Coca-Cola, to a multi-domestic marketing approach?
Directory of Open Access Journals (Sweden)
S. Bathiany
2013-02-01
Full Text Available Early warning signals (EWS have become a popular statistical tool to infer stability properties of the climate system. In Part 1 of this two-part paper we have presented a diagnostic method to find the hotspot of a sudden transition as opposed to regions that experience an externally induced tipping as a mere response. Here, we apply our method to the atmosphere–vegetation model PlanetSimulator (PlaSim – VECODE using a regression model. For each of two vegetation collapses in PlaSim-VECODE, we identify a hotspot of one particular grid cell. We demonstrate with additional experiments that the detected hotspots are indeed a particularly sensitive region in the model and give a physical explanation for these results. The method can thus provide information on the causality of sudden transitions and may help to improve the knowledge on the vulnerability of certain subsystems in climate models.
International Nuclear Information System (INIS)
Bouffard, M.; Engelmann, J.
1975-01-01
Two possible versions of an experiment for launch aboard an ESRO free-flyer spacecraft in the 1980's are described. All the data quoted are, of course, preliminary. They may be used only as a basis for discussion although they are derived from well-known balloon hardware. The telescope arrangement, the description of counter, drift chamber and electronics are given [fr
Vanacker, V.
2012-04-01
The surface of the Earth is changing rapidly, largely in response to anthropogenic perturbation. Direct anthropogenic disturbance of natural environments may be much larger in many places than the (projected) indirect effects of climate change. There is now large evidence that humans have significantly altered geomorphic process rates, mainly through changes in vegetation composition, density and cover. While much attention has been given to the impact of vegetation degradation on geomorphic process rates, I suggest that the pathway of restoration is equally important to investigate. First, vegetation recovery after crop abandonment has a rapid and drastic impact on geomorphic process rates. Our data from degraded catchments in the tropical Andes show that erosion rates can be reduced by up to 100 times when increasing the protective vegetation cover. During vegetation restoration, the combined effects of the reduction in surface runoff, sediment production and hydrological connectivity are stronger than the individual effects together. Therefore, changes in erosion and sedimentation during restoration are not simply the reverse of those observed during degradation. Second, anthropogenic perturbation causes a profound but often temporary change in geomorphic process rates. Reconstruction of soil erosion rates in Spain shows us that modern erosion rates in well-vegetated areas are similar to long-term rates, despite evidence of strong pulses in historical erosion rates after vegetation clearance and agriculture. The soil vegetation system might be resilient to short pulses of accelerated erosion (and deposition), as there might exist a dynamic coupling between soil erosion and production also in degraded environments.
Godoy, O.; Castro Diez, P.; van Logtestijn, R.S.P; Cornelissen, J.H.C.; Valladares, F.
2010-01-01
Leaf traits related to the performance of invasive alien species can influence nutrient cycling through litter decomposition. However, there is no consensus yet about whether there are consistent differences in functional leaf traits between invasive and native species that also manifest themselves
Experimental study of the slowing down of heavy ions at 20 to 100 MeV per nucleon in matter
International Nuclear Information System (INIS)
Herault, J.
1988-01-01
The measurements of typical parameters on heavy ions penetration through matter presented in this work have been performed at the GANIL accelerator facility, using the LISE magnetic spectrometer from 20 to 100 MeV per nucleon. Two magnetic optical configurations of the spectrometer LISE corresponding respectively to energy and angle analysis, have been used. In the first configuration, the analysis of the energy loss distribution, caused by the interaction of the heavy ions beam with the target material, permit to determine the stopping power and the energy straggling. The stopping power is defined experimentally by the ratio of the average energy loss in the target to the thickness of this one. This quantity has been measured for a set of heavy ions ( 17 O, 40 Ar, 86 Kr and 132 Xe) in gaseous media (H 2 , He, N 2 , Ne, Ar, Kr, Xe, CH 4 , C 4 H 10 , CO 2 and CF 4 ) and compared to semi-empirical tabulations. These determinations are compared to those obtained in solid media to study the evolution of the solid-gas difference. This effect vanishes progressively when the projectile tends to be totally stripped (the charge state becomes identical to the atomic number). The heavy ion energy distributions at the exit of degraders and particularly their full width at half maximum have been measured for various projectiles ( 16 O, 40 Ar, 84 Kr, 86 Kr, 100 Mo and 132 Xe) in solid (Be, C, Al, Si, Ti, Ni, Cu, Ag, Ta, Au and Mylar) and gaseous media (the same as for stopping power determinations). A significant contribution of charge exchange straggling to the energy loss straggling is observed for partially stripped ions. A second optical configuration of the beam line LISE has been used, to obtain an image of heavy ions beams passing through targets for various heavy ions ( 16 O, 17 O, 40 Ar, 86 Kr and 100 Mo) in gaseous and solid media. The scaling law for angular straggling is confirmed and extended over five orders of magnitude [fr
Nicenboim, Bruno; Logačev, Pavel; Gattei, Carolina; Vasishth, Shravan
2016-01-01
We examined the effects of argument-head distance in SVO and SOV languages (Spanish and German), while taking into account readers' working memory capacity and controlling for expectation (Levy, 2008) and other factors. We predicted only locality effects, that is, a slowdown produced by increased dependency distance (Gibson, 2000; Lewis and Vasishth, 2005). Furthermore, we expected stronger locality effects for readers with low working memory capacity. Contrary to our predictions, low-capacity readers showed faster reading with increased distance, while high-capacity readers showed locality effects. We suggest that while the locality effects are compatible with memory-based explanations, the speedup of low-capacity readers can be explained by an increased probability of retrieval failure. We present a computational model based on ACT-R built under the previous assumptions, which is able to give a qualitative account for the present data and can be tested in future research. Our results suggest that in some cases, interpreting longer RTs as indexing increased processing difficulty and shorter RTs as facilitation may be too simplistic: The same increase in processing difficulty may lead to slowdowns in high-capacity readers and speedups in low-capacity ones. Ignoring individual level capacity differences when investigating locality effects may lead to misleading conclusions.
Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals
Alanko, T; Kylloenen, V; Müller, S; Raeisaenen, J; Virtanen, A
2000-01-01
Stopping powers for 1.3-3.5 MeV/u sup 5 sup 6 Fe, sup 8 sup 0 sup , sup 8 sup 4 Kr and sup 1 sup 2 sup 7 I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for sup 8 sup 4 Kr and sup 5 sup 6 Fe in Ni, Cu, and Au.
International Nuclear Information System (INIS)
Sanders, Lloyd P; Fogelmark, Karl; Ambjörnsson, Tobias; Lomholt, Michael A; Lizana, Ludvig; Metzler, Ralf
2014-01-01
Low-dimensional, many-body systems are often characterized by ultraslow dynamics. We study a labelled particle in a generic system of identical particles with hard-core interactions in a strongly disordered environment. The disorder is manifested through intermittent motion with scale-free sticking times at the single particle level. While for a non-interacting particle we find anomalous diffusion of the power-law form 〈x 2 (t)〉≃t α of the mean squared displacement with 0<α<1, we demonstrate here that the combination of the disordered environment with the many-body interactions leads to an ultraslow, logarithmic dynamics 〈x 2 (t)〉≃log 1/2 t with a universal 1/2 exponent. Even when a characteristic sticking time exists but the fluctuations of sticking times diverge we observe the mean squared displacement 〈x 2 (t)〉≃t γ with 0<γ<1/2, that is slower than the famed Harris law 〈x 2 (t)〉≃t 1/2 without disorder. We rationalize the results in terms of a subordination to a counting process, in which each transition is dominated by the forward waiting time of an ageing continuous time process. (paper)
Psoriasis Doesn't Slow Down Texan Brian LaFoy | NIH MedlinePlus the Magazine
... willing to do. I'm one of the lucky ones." Find Out More National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) MedlinePlus-Psoriasis Clinical Trials Search Psoriasis Spring 2017 Issue: Volume 12 Number 1 Page 22 MedlinePlus Subscribe Magazine Information Contact ...
FOXO/DAF-16 Activation Slows Down Turnover of the Majority of Proteins in C. elegans
Energy Technology Data Exchange (ETDEWEB)
Dhondt, Ineke; Petyuk, Vladislav A.; Cai, Huaihan; Vandemeulebroucke, Lieselot; Vierstraete, Andy; Smith, Richard D.; Depuydt, Geert; Braeckman, Bart P.
2016-09-01
Cellular protein quality can be maintained by proteolytic elimination of damaged proteins and replacing them with newly synthesized copies, a process called protein turnover (Ward, 2000). Protein turnover rates have been estimated using SILAC (stable isotope labeling by amino acids in cell culture) in prokaryotes and eukaryotes. The last decade has witnessed a growing interest in the analysis of whole-organism proteome dynamics in metazoans using the same approach (Claydon and Beynon, 2012). In recent work, SILAC was applied to monitor protein synthesis throughout life in adult Caenorhabditis elegans (Vukoti et al., 2015) and to investigate food intake (Gomez-Amaro et al., 2015
Slowing down of 1.3-3.5 MeV/u Fe, Kr and I ions in ten metals
Energy Technology Data Exchange (ETDEWEB)
Alanko, T. E-mail: tommi.alanko@phys.jyu.fi; Hyvoenen, J.; Kylloenen, V.; Mueller, S.; Raeisaenen, J.; Virtanen, A
2000-09-01
Stopping powers for 1.3-3.5 MeV/u {sup 56}Fe, {sup 80,84}Kr and {sup 127}I ions in Mg, V, Fe, Co, Ni, Cu, Nb, Sn, Ta and Au have been determined by a transmission technique exposing the metallic sample foils to the direct ion beam. No previous data have been published for Mg, V, Fe, Co, Nb, Sn or Ta stopping media with these ion energies. The experimental results are compared with parametrizations of the stopping powers found in the literature (SRIM-2000 and Hubert's parametrization). Discrepancies as high as 21 and 16% are observed for SRIM and Hubert's parametrization, respectively. However, there is agreement between the present results and other experimental data available at corresponding ion velocities for {sup 84}Kr and {sup 56}Fe in Ni, Cu, and Au.
Liu, Ronggang; Liu, Tong; Wang, Yingying; Li, Yujie; Gai, Bingzheng
2017-11-01
We propose an effective method to achieve extremely slow light by using both the mechanism of electromagnetically induced transparency (EIT) and the localization of a coupled cavity waveguide (CCW). Based on quantum mechanics theory and the dispersion relation of a CCW, we derive a group-velocity formula that reveals both the effects of the EIT and CCW. Results show that ultralow light velocity at the order of several meters per second or even static light, could be obtained feasibly. In comparison with the EIT mechanism in a background of vacuum, this proposed method is more effective and realistic to achieve extremely slow light. And it exhibits potential values in the field of light storage.
Kaal, Esta, 1962-
2001-01-01
Viimse 10 aasta jooksul toimunud muutustest inimeste tarbimisharjumustes. Tarbijad on muutunud palju valivamaks ning koos tarbijakäitumisega on muutunud ka turundusstrateegiad. Diagrammid: kulutuste jagunemine toidu, transpordi, majapidamise ning riietuse vahel Eestis, Leedus, Poolas ja Soomes 1998; kulutused reklaamile erinevates meediakanalites 2001 I-III kvartal
Energy Technology Data Exchange (ETDEWEB)
Raievski, V; Horowitz, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1955-07-01
The further method is the outcome of a technique used in the study of neutrons in scattering and slowing-down environment. In this technique, we replace the constant sources used in the classic experiences by modulated sources with a variable frequency. The object of this article is to describe the extension of the method for the mean free path for transport of thermal neutrons and also to indicate the possible applications for other sizes, as the slowing length, or the absolute value of the cross-section of the boron. (M.B.) [French] La methode qui va etre decrite est l'aboutissement d'une technique utilisee dans l'etude des milieux ou diffusent et se ralentissent des neutrons. Dans cette technique, on remplace les sources constantes utilisees dans les experiences classiques par des sources modulees, a frequence variable. L'objet de cet article est de decrire l'extension de la methode a la mesure du libre parcours moyen de transport des neutrons thermiques et egalement d'indiquer les applications possibles a la mesure d'autres grandeurs, telles que la longueur de ralentissement, ou la valeur absolue de la section de capture du bore. (M.B.)
Short Rayleigh Length Free Electron Lasers
Crooker, P P; Armstead, R L; Blau, J
2004-01-01
Conventional free electron laser (FEL) oscillators minimize the optical mode volume around the electron beam in the undulator by making the resonator Rayleigh length about one third of the undulator length. This maximizes gain and beam-mode coupling. In compact configurations of high-power infrared FELs or moderate power UV FELs, the resulting optical intensity can damage the resonator mirrors. To increase the spot size and thereby reduce the optical intensity at the mirrors below the damage threshold, a shorter Rayleigh length can be used, but the FEL interaction is significantly altered. A new FEL interaction is described and analyzed with a Rayleigh length that is only one tenth the undulator length, or less. The effect of mirror vibration and positioning are more critical in the short Rayleigh length design, but we find that they are still within normal design tolerances.
Length dependent properties of SNS microbridges
International Nuclear Information System (INIS)
Sauvageau, J.E.; Jain, R.K.; Li, K.; Lukens, J.E.; Ono, R.H.
1985-01-01
Using an in-situ, self-aligned deposition scheme, arrays of variable length SNS junctions in the range of 0.05 μm to 1 μm have been fabricated. Arrays of SNS microbridges of lead-copper and niobium-copper fabricated using this technique have been used to study the length dependence, at constant temperature, of the critical current I and bridge resistance R /SUB d/ . For bridges with lengths pounds greater than the normal metal coherence length xi /SUB n/ (T), the dependence of I /SUB c/ on L is consistent with an exponential dependence on the reduced length l=L/xi /SUB n/ (T). For shorter bridges, deviations from this behavior is seen. It was also found that the bridge resistance R /SUB d/ does not vary linearly with the geometric bridge length but appears to approach a finite value as L→O
Measuring Crack Length in Coarse Grain Ceramics
Salem, Jonathan A.; Ghosn, Louis J.
2010-01-01
Due to a coarse grain structure, crack lengths in precracked spinel specimens could not be measured optically, so the crack lengths and fracture toughness were estimated by strain gage measurements. An expression was developed via finite element analysis to correlate the measured strain with crack length in four-point flexure. The fracture toughness estimated by the strain gaged samples and another standardized method were in agreement.
Dither Cavity Length Controller with Iodine Locking
Directory of Open Access Journals (Sweden)
Lawson Marty
2016-01-01
Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.
Information, polarization and term length in democracy
DEFF Research Database (Denmark)
Schultz, Christian
2008-01-01
This paper considers term lengths in a representative democracy where the political issue divides the population on the left-right scale. Parties are ideologically different and better informed about the consequences of policies than voters are. A short term length makes the government more...... accountable, but the re-election incentive leads to policy-distortion as the government seeks to manipulate swing voters' beliefs to make its ideology more popular. This creates a trade-off: A short term length improves accountability but gives distortions. A short term length is best for swing voters when...
Manfré, Giuseppe; Novati, Arianna; Faccini, Ilaria; Rossetti, Andrea C; Bosch, Kari; Molteni, Raffaella; Riva, Marco A; Van der Harst, Johanneke E; Nguyen, Huu Phuc; Homberg, Judith R
2018-01-01
Huntington disease (HD) is a devastating inherited neurodegenerative disorder characterized by progressive motor, cognitive, and psychiatric symptoms without any cure to slow down or stop the progress of the disease. The BACHD rat model for HD carrying the human full-length mutant huntingtin protein (mHTT) with 97 polyQ repeats has been recently established as a promising model which reproduces several HD-like features. While motor and cognitive functions have been characterized in BACHD rats, little is known about their social phenotype. This study focuses especially on social behavior since evidence for social disturbances exists in human patients. Our objective was to compare social behavior in BACHD and wild-type (WT) rats at different ages, using two different measures of sociability. Animals were tested longitudinally at the age of 2, 4 and 8 months in the social interaction test to examine different parameters of sociability. A separate cohort of 7 month old rats was tested in the three chamber social test to measure both sociability and social novelty. Gene expression analyses in 8 months old animals were performed by real time qRT-PCR to evaluate a potential involvement of D1 and D2 dopaminergic receptors and the contribution of Brain-derived neurotrophic factor (BDNF) to the observed behavioral alterations. In the social interaction test, BACHD rats showed age-dependent changes in behaviour when they were-re introduced to their cagemate after a 24 hours-period of individual housing. The time spent on nape attacks increased with aging. Furthermore, a significant higher level of pinning at 2 months of age was shown in the BACHD rats compared to wild-types, followed by a reduction at 4 and 8 months. On the other hand, BACHD rats exhibited a decreased active social behaviour compared to wild-types, reflected by genotype-effects on approaching, following and social nose contact. In the three chamber social test, BACHD rats seemed to show a mild deficit in
Directory of Open Access Journals (Sweden)
Giuseppe Manfré
Full Text Available Huntington disease (HD is a devastating inherited neurodegenerative disorder characterized by progressive motor, cognitive, and psychiatric symptoms without any cure to slow down or stop the progress of the disease. The BACHD rat model for HD carrying the human full-length mutant huntingtin protein (mHTT with 97 polyQ repeats has been recently established as a promising model which reproduces several HD-like features. While motor and cognitive functions have been characterized in BACHD rats, little is known about their social phenotype.This study focuses especially on social behavior since evidence for social disturbances exists in human patients. Our objective was to compare social behavior in BACHD and wild-type (WT rats at different ages, using two different measures of sociability.Animals were tested longitudinally at the age of 2, 4 and 8 months in the social interaction test to examine different parameters of sociability. A separate cohort of 7 month old rats was tested in the three chamber social test to measure both sociability and social novelty. Gene expression analyses in 8 months old animals were performed by real time qRT-PCR to evaluate a potential involvement of D1 and D2 dopaminergic receptors and the contribution of Brain-derived neurotrophic factor (BDNF to the observed behavioral alterations.In the social interaction test, BACHD rats showed age-dependent changes in behaviour when they were-re introduced to their cagemate after a 24 hours-period of individual housing. The time spent on nape attacks increased with aging. Furthermore, a significant higher level of pinning at 2 months of age was shown in the BACHD rats compared to wild-types, followed by a reduction at 4 and 8 months. On the other hand, BACHD rats exhibited a decreased active social behaviour compared to wild-types, reflected by genotype-effects on approaching, following and social nose contact. In the three chamber social test, BACHD rats seemed to show a mild
Manfré, Giuseppe; Novati, Arianna; Faccini, Ilaria; Rossetti, Andrea C.; Bosch, Kari; Molteni, Raffaella; Riva, Marco A.; Van der Harst, Johanneke E.; Homberg, Judith R.
2018-01-01
Background Huntington disease (HD) is a devastating inherited neurodegenerative disorder characterized by progressive motor, cognitive, and psychiatric symptoms without any cure to slow down or stop the progress of the disease. The BACHD rat model for HD carrying the human full-length mutant huntingtin protein (mHTT) with 97 polyQ repeats has been recently established as a promising model which reproduces several HD-like features. While motor and cognitive functions have been characterized in BACHD rats, little is known about their social phenotype. Objective This study focuses especially on social behavior since evidence for social disturbances exists in human patients. Our objective was to compare social behavior in BACHD and wild-type (WT) rats at different ages, using two different measures of sociability. Methods Animals were tested longitudinally at the age of 2, 4 and 8 months in the social interaction test to examine different parameters of sociability. A separate cohort of 7 month old rats was tested in the three chamber social test to measure both sociability and social novelty. Gene expression analyses in 8 months old animals were performed by real time qRT-PCR to evaluate a potential involvement of D1 and D2 dopaminergic receptors and the contribution of Brain-derived neurotrophic factor (BDNF) to the observed behavioral alterations. Results In the social interaction test, BACHD rats showed age-dependent changes in behaviour when they were-re introduced to their cagemate after a 24 hours-period of individual housing. The time spent on nape attacks increased with aging. Furthermore, a significant higher level of pinning at 2 months of age was shown in the BACHD rats compared to wild-types, followed by a reduction at 4 and 8 months. On the other hand, BACHD rats exhibited a decreased active social behaviour compared to wild-types, reflected by genotype-effects on approaching, following and social nose contact. In the three chamber social test, BACHD rats
Length scale for configurational entropy in microemulsions
Reiss, H.; Kegel, W.K.; Groenewold, J.
1996-01-01
In this paper we study the length scale that must be used in evaluating the mixing entropy in a microemulsion. The central idea involves the choice of a length scale in configuration space that is consistent with the physical definition of entropy in phase space. We show that this scale may be
Proofs of Contracted Length Non-covariance
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1994-01-01
Different proofs of contracted length non covariance are discussed. The way based on the establishment of interval inconstancy (dependence on velocity) seems to be the most convincing one. It is stressed that the known non covariance of the electromagnetic field energy and momentum of a moving charge ('the problem 4/3') is a direct consequence of contracted length non covariance. 8 refs
The length of the male urethra
Directory of Open Access Journals (Sweden)
Tobias. S. Kohler
2008-08-01
Full Text Available PURPOSE: Catheter-based medical devices are an important component of the urologic armamentarium. To our knowledge, there is no population-based data regarding normal male urethral length. We evaluated the length of the urethra in men with normal genitourinary anatomy undergoing either Foley catheter removal or standard cystoscopy. MATERIALS AND METHODS: Male urethral length was obtained in 109 men. After study permission was obtained, the subject's penis was placed on a gentle stretch and the catheter was marked at the tip of the penis. The catheter was then removed and the distance from the mark to the beginning of the re-inflated balloon was measured. Alternatively, urethral length was measured at the time of cystoscopy, on removal of the cystoscope. Data on age, weight, and height was obtained in patients when possible. RESULTS: The mean urethral length was 22.3 cm with a standard deviation of 2.4 cm. Urethral length varied between 15 cm and 29 cm. No statistically significant correlation was found between urethral length and height, weight, body mass index (BMI, or age. CONCLUSIONS: Literature documenting the length of the normal male adult urethra is scarce. Our data adds to basic anatomic information of the male urethra and may be used to optimize genitourinary device design.
Analysis of ureteral length in adult cadavers
Directory of Open Access Journals (Sweden)
Hugo F. F. Novaes
2013-04-01
Full Text Available Introduction In some occasions, correlations between human structures can help planning surgical intra-abdominal interventions. The previous determination of ureteral length helps pre-operatory planning of surgeries, reduces costs of auxiliary exams, the correct choice of double-J catheter with low morbidity and fewer symptoms, and an adequate adhesion to treatment. Objective To evaluate ureteral length in adult cadavers and to analyze its correlation with anthropometric measures. Materials and Methods: From April 2009 to January 2012 we determined ureteral length of adult cadavers submitted to necropsy and obtained the following measures: height, distance from shoulder to wrist, elbow-wrist, xiphoid appendix-umbilicus, umbilicus-pubis, xiphoid appendix-pubis and between iliac spines. We analyzed the correlations between ureteral length and those anthropometric measures. Results We dissected 115 ureters from 115 adult corpses from April 2009 to January 2012. Median ureteral length didn't vary between sexes or according to height. It was observed no correlation among ureteral length and all considered anthropometric measures in all analyzed subgroups and in general population. There were no significant differences between right and left ureteral measures. Conclusions There is no difference of ureteral length in relation to height or gender (male or female. There is no significant correlation among ureteral length and the considered anthropometric measures.
Influence of mandibular length on mouth opening
Dijkstra, PU; Hof, AL; Stegenga, B; De Bont, LGM
Theoretically, mouth opening not only reflects the mobility of the temporomandibular joints (TMJs) but also the mandibular length. Clinically, the exact relationship between mouth opening, mandibular length, and mobility of TMJs is unclear. To study this relationship 91 healthy subjects, 59 women
Economic issues of broiler production length
Directory of Open Access Journals (Sweden)
Szőllősi László
2014-01-01
Full Text Available The length of broiler production cycle is also an important factor when profitability is measured. This paper is to determine the effects of different market ages and down-time period, overall broiler production cycle length on performance and economic parameters based on Hungarian production and financial circumstances. A deterministic model was constructed to manage the function-like correlations of age-related daily weight gain, daily feed intake and daily mortality data. The results show that broiler production cycle length has a significant effect on production and economic performance. Cycle length is determined by the length of down-time and grow-out periods. If down-time period is reduced by one day, an average net income of EUR 0.55 per m2 is realizable. However, the production period is not directly proportional either with emerging costs or obtainable revenues. Profit maximization is attainable if the production period is 41-42 days.
Roentgenologic investigations for the anterior tooth length
Energy Technology Data Exchange (ETDEWEB)
Cho, Won Pyo; Ahn, Hyung Kyu [College of Dentistry, Seoul National University , Seoul (Korea, Republic of)
1972-11-15
The author measured the length of crown, root and tooth on the films which was taken by intraoral bisecting technic with mesh plate on the films. The films were taken from the dry skulls, dentiform, same patients who had to be removed their upper incisors, and the other patients who admitted for dental care. From this serial experiment the results were made as follows: 1. By using the film and mesh plate in the oral cavity, the real tooth length can be measured easily on the film surfaces. 2. The film distortion in the oral cavity can be avoided when taking the film using the mesh plate and film together. 3. When measuring the film, length of crown was elongated and length of root was shortened. 4. When using the well-trained bisecting technic, the real tooth length can be measured directly on the intraoral film.
Screening length in dusty plasma crystals
International Nuclear Information System (INIS)
Nikolaev, V S; Timofeev, A V
2016-01-01
Particles interaction and value of the screening length in dusty plasma systems are of great interest in dusty plasma area. Three inter-particle potentials (Debye potential, Gurevich potential and interaction potential in the weakly collisional regime) are used to solve equilibrium equations for two dusty particles suspended in a parabolic trap. The inter-particle distance dependence on screening length, trap parameter and particle charge is obtained. The functional form of inter-particle distance dependence on ion temperature is investigated and compared with experimental data at 200-300 K in order to test used potentials applicability to dusty plasma systems at room temperatures. The preference is given to the Yukawa-type potential including effective values of particle charge and screening length. The estimated effective value of the screening length is 5-15 times larger than the Debye length. (paper)
Microcomputer system for controlling fuel rod length
International Nuclear Information System (INIS)
Meyer, E.R.; Bouldin, D.W.; Bolfing, B.J.
1979-01-01
A system is being developed at the Oak Ridge National Laboratory (ORNL) to automatically measure and control the length of fuel rods for use in a high temperature gas-cooled reactor (HTGR). The system utilizes an LSI-11 microcomputer for monitoring fuel rod length and for adjusting the primary factor affecting length. Preliminary results indicate that the automated system can maintain fuel rod length within the specified limits of 1.940 +- 0.040 in. This system provides quality control documentation and eliminates the dependence of the current fuel rod molding process on manual length control. In addition, the microcomputer system is compatible with planned efforts to extend control to fuel rod fissile and fertile material contents
Kidney Length in Normal Korean Children
International Nuclear Information System (INIS)
Kim, In One; Cheon, Jung Eun; Lee, Young Seok; Lee, Sun Wha; Kim, Ok Hwa; Kim, Ji Hye; Kim, Hong Dae; Sim, Jung Suk
2010-01-01
Renal length offers important information to detect or follow-up various renal diseases. The purpose of this study was to determine the kidney length of normal Korean children in relation to age, height, weight, body surface area (BSA), and body mass index (BMI). Children between 1 month and 15 years of age without urological abnormality were recruited. Children below 3rd percentile and over 97th percentile for height or weight were excluded. Both renal lengths were measured in the prone position three times and then averaged by experienced radiologists. The mean length and standard deviation for each age group was obtained, and regression equation was calculated between renal length and age, weight, height, BSA, and BMI, respectively. Renal length was measured in 550 children. Renal length grows rapidly until 24 month, while the growth rate is reduced thereafter. The regression equation for age is: renal length (mm) = 45.953 + 1.064 x age (month, ≤ 24 months) (R2 = 0.720) or 62.173 + 0.203 x age (months, > 24 months) (R2 = 0.711). The regression equation for height is: renal length (mm) = 24.494 + 0.457 x height (cm) (R2 = 0.894). The regression equation for weight is: renal length (mm) = 38.342 + 2.117 x weight (kg, ≤18 kg) (R2 = 0.852) or 64.498 + 0.646 x weight (kg, > 18 kg) (R2 = 0.651). The regression equation for BSA is: renal length (mm) = 31.622 + 61.363 x BSA (m2, ≤ 0.7) (R2 = 0.857) or 52.717 + 29.959 x BSA (m2, > 0.7) (R2 = 0.715). The regression equation for BMI is: renal length (mm) = 44.474 + 1.163 x BMI (R2 = 0.079). This study provides data on the normal renal length and its association with age, weight, height, BSA and BMI. The results of this study will guide the detection and follow-up of renal diseases in Korean children
Zero-point length from string fluctuations
International Nuclear Information System (INIS)
Fontanini, Michele; Spallucci, Euro; Padmanabhan, T.
2006-01-01
One of the leading candidates for quantum gravity, viz. string theory, has the following features incorporated in it. (i) The full spacetime is higher-dimensional, with (possibly) compact extra-dimensions; (ii) there is a natural minimal length below which the concept of continuum spacetime needs to be modified by some deeper concept. On the other hand, the existence of a minimal length (zero-point length) in four-dimensional spacetime, with obvious implications as UV regulator, has been often conjectured as a natural aftermath of any correct quantum theory of gravity. We show that one can incorporate the apparently unrelated pieces of information-zero-point length, extra-dimensions, string T-duality-in a consistent framework. This is done in terms of a modified Kaluza-Klein theory that interpolates between (high-energy) string theory and (low-energy) quantum field theory. In this model, the zero-point length in four dimensions is a 'virtual memory' of the length scale of compact extra-dimensions. Such a scale turns out to be determined by T-duality inherited from the underlying fundamental string theory. From a low energy perspective short distance infinities are cutoff by a minimal length which is proportional to the square root of the string slope, i.e., α ' . Thus, we bridge the gap between the string theory domain and the low energy arena of point-particle quantum field theory
Penile length and circumference: an Indian study.
Promodu, K; Shanmughadas, K V; Bhat, S; Nair, K R
2007-01-01
Apprehension about the normal size of penis is a major concern for men. Aim of the present investigation is to estimate the penile length and circumference of Indian males and to compare the results with the data from other countries. Results will help in counseling the patients worried about the penile size and seeking penis enlargement surgery. Penile length in flaccid and stretched conditions and circumference were measured in a group of 301 physically normal men. Erected length and circumference were measured for 93 subjects. Mean flaccid length was found to be 8.21 cm, mean stretched length 10.88 cm and circumference 9.14 cm. Mean erected length was found to be 13.01 cm and erected circumference was 11.46 cm. Penile dimensions are found to be correlated with anthropometric parameters. Insight into the normative data of penile size of Indian males obtained. There are significant differences in the mean penile length and circumference of Indian sample compared to the data reported from other countries. Study need to be continued with a large sample to establish a normative data applicable to the general population.
Automatic Control Of Length Of Welding Arc
Iceland, William F.
1991-01-01
Nonlinear relationships among current, voltage, and length stored in electronic memory. Conceptual microprocessor-based control subsystem maintains constant length of welding arc in gas/tungsten arc-welding system, even when welding current varied. Uses feedback of current and voltage from welding arc. Directs motor to set position of torch according to previously measured relationships among current, voltage, and length of arc. Signal paths marked "calibration" or "welding" used during those processes only. Other signal paths used during both processes. Control subsystem added to existing manual or automatic welding system equipped with automatic voltage control.
Bunch Length Measurements in SPEAR3
Energy Technology Data Exchange (ETDEWEB)
Corbett, W.J.; Fisher, A.; Huang, X.; Safranek, J.; Sebek, J.; /SLAC; Lumpkin, A.; /Argonne; Sannibale, F.; /LBL, Berkeley; Mok, W.; /Unlisted
2007-11-28
A series of bunch length measurements were made in SPEAR3 for two different machine optics. In the achromatic optics the bunch length increases from the low-current value of 16.6ps rms to about 30ps at 25ma/bunch yielding an inductive impedance of -0.17{Omega}. Reducing the momentum compaction factor by a factor of {approx}60 [1] yields a low-current bunch length of {approx}4ps rms. In this paper we review the experimental setup and results.
The benefits of longer fuel cycle lengths
International Nuclear Information System (INIS)
Kesler, D.C.
1986-01-01
Longer fuel cycle lengths have been found to increase generation and improve outage management. A study at Duke Power Company has shown that longer fuel cycles offer both increased scheduling flexibility and increased capacity factors
Atomic frequency-time-length standards
International Nuclear Information System (INIS)
Gheorghiu, O.C.; Mandache, C.
1987-01-01
The principles of operative of atomic frequency-time-length standards and their principle characteristics are described. The role of quartz crystal oscillators which are sloved to active or passive standards is presented. (authors)
The analysis of projected fission track lengths
International Nuclear Information System (INIS)
Laslett, G.M.; Galbraith, R.F.; Green, P.F.
1994-01-01
This article deals with the question of how features of the thermal history can be estimated from projected track length measurements, i.e. lengths of the remaining parts of tracks that have intersected a surface, projected onto that surface. The appropriate mathematical theory is described and used to provide a sound basis both for understanding the nature of projected length measurements and for analysing observed data. The estimation of thermal history parameters corresponding to the current temperature, the maximum palaeotemperature and the time since cooling, is studied using laboratory data and simulations. In general the information contained in projected track lengths and angles is fairly limited, compared, for example, with that from a much smaller number of confined tracks, though we identify some circumstances when such measurements may be useful. Also it is not straightforward to extract the information and simple ad hoc estimation methods are generally inadequate. (author)
Complementary DNA-amplified fragment length polymorphism ...
African Journals Online (AJOL)
Complementary DNA-amplified fragment length polymorphism (AFLP-cDNA) analysis of differential gene expression from the xerophyte Ammopiptanthus mongolicus in response to cold, drought and cold together with drought.
Impedance of finite length resistive cylinder
Directory of Open Access Journals (Sweden)
S. Krinsky
2004-11-01
Full Text Available We determine the impedance of a cylindrical metal tube (resistor of radius a, length g, and conductivity σ attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency (k≫1/a. In the equilibrium regime, ka^{2}≪g, the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity σ. In the transient regime, ka^{2}≫g, where the contribution of transition radiation arising from the discontinuity in conductivity is important, we derive an analytic expression for the impedance and compute the short-range wakefield. The analytic results are shown to agree with numerical evaluation of the impedance.
Characteristic length of the knotting probability revisited
International Nuclear Information System (INIS)
Uehara, Erica; Deguchi, Tetsuo
2015-01-01
We present a self-avoiding polygon (SAP) model for circular DNA in which the radius of impermeable cylindrical segments corresponds to the screening length of double-stranded DNA surrounded by counter ions. For the model we evaluate the probability for a generated SAP with N segments having a given knot K through simulation. We call it the knotting probability of a knot K with N segments for the SAP model. We show that when N is large the most significant factor in the knotting probability is given by the exponentially decaying part exp(−N/N K ), where the estimates of parameter N K are consistent with the same value for all the different knots we investigated. We thus call it the characteristic length of the knotting probability. We give formulae expressing the characteristic length as a function of the cylindrical radius r ex , i.e. the screening length of double-stranded DNA. (paper)
Chord length distribution for a compound capsule
International Nuclear Information System (INIS)
Pitřík, Pavel
2017-01-01
Chord length distribution is a factor important in the calculation of ionisation chamber responses. This article describes Monte Carlo calculations of the chord length distribution for a non-convex compound capsule. A Monte Carlo code was set up for generation of random chords and calculation of their lengths based on the input number of generations and cavity dimensions. The code was written in JavaScript and can be executed in the majority of HTML viewers. The plot of occurrence of cords of different lengths has 3 peaks. It was found that the compound capsule cavity cannot be simply replaced with a spherical cavity of a triangular design. Furthermore, the compound capsule cavity is directionally dependent, which must be taken into account in calculations involving non-isotropic fields of primary particles in the beam, unless equilibrium of the secondary charged particles is attained. (orig.)
Study on the Connecting Length of CFRP
Liu, Xiongfei; Li, Yue; Li, Zhanguo
2018-05-01
The paper studied the varying mode of shear stress in the connecting zone of CFRP. Using epoxy resin (EP) as bond material, performance of specimens with different connecting length of CFRP was tested to obtain the conclusion. CFRP-confined concrete column was tested subsequently to verify the conclusion. The results show that: (1) The binding properties of modified epoxy resin with CFRP is good; (2) As the connecting length increased, the ultimate tensile strength of CFRP increased as well in the range of the experiment parameters; (3) Tensile strength of CFRP can reach the ultimate strength when the connecting length is 90mm;(4) The connecting length of 90mm of CFRP meet the reinforcement requirements.
Fragment Length of Circulating Tumor DNA.
Underhill, Hunter R; Kitzman, Jacob O; Hellwig, Sabine; Welker, Noah C; Daza, Riza; Baker, Daniel N; Gligorich, Keith M; Rostomily, Robert C; Bronner, Mary P; Shendure, Jay
2016-07-01
Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.
Electron Effective-Attenuation-Length Database
SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge) This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
Length and coverage of inhibitory decision rules
Alsolami, Fawaz
2012-01-01
Authors present algorithms for optimization of inhibitory rules relative to the length and coverage. Inhibitory rules have a relation "attribute ≠ value" on the right-hand side. The considered algorithms are based on extensions of dynamic programming. Paper contains also comparison of length and coverage of inhibitory rules constructed by a greedy algorithm and by the dynamic programming algorithm. © 2012 Springer-Verlag.
The SME gauge sector with minimum length
Energy Technology Data Exchange (ETDEWEB)
Belich, H.; Louzada, H.L.C. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil)
2017-12-15
We study the gauge sector of the Standard Model Extension (SME) with the Lorentz covariant deformed Heisenberg algebra associated to the minimum length. In order to find and estimate corrections, we clarify whether the violation of Lorentz symmetry and the existence of a minimum length are independent phenomena or are, in some way, related. With this goal, we analyze the dispersion relations of this theory. (orig.)
The SME gauge sector with minimum length
Belich, H.; Louzada, H. L. C.
2017-12-01
We study the gauge sector of the Standard Model Extension (SME) with the Lorentz covariant deformed Heisenberg algebra associated to the minimum length. In order to find and estimate corrections, we clarify whether the violation of Lorentz symmetry and the existence of a minimum length are independent phenomena or are, in some way, related. With this goal, we analyze the dispersion relations of this theory.
length-weight relationhip of freshwater wild fish species
African Journals Online (AJOL)
Dr Naeem
2012-06-21
Jun 21, 2012 ... Length-weight (LWR) and length-length relationships (LLR) were determined for a freshwater catfish ... Key words: Mystus bleekeri, length-weight relationship, length-length relationship, predictive equations. INTRODUCTION. Mystus bleekeri (freshwater catfish Day, 1877), locally ..... fish farmers, Aquacult.
Length expectation values in quantum Regge calculus
International Nuclear Information System (INIS)
Khatsymovsky, V.M.
2004-01-01
Regge calculus configuration superspace can be embedded into a more general superspace where the length of any edge is defined ambiguously depending on the 4-tetrahedron containing the edge. Moreover, the latter superspace can be extended further so that even edge lengths in each the 4-tetrahedron are not defined, only area tensors of the 2-faces in it are. We make use of our previous result concerning quantization of the area tensor Regge calculus which gives finite expectation values for areas. Also our result is used showing that quantum measure in the Regge calculus can be uniquely fixed once we know quantum measure on (the space of the functionals on) the superspace of the theory with ambiguously defined edge lengths. We find that in this framework quantization of the usual Regge calculus is defined up to a parameter. The theory may possess nonzero (of the order of Planck scale) or zero length expectation values depending on whether this parameter is larger or smaller than a certain value. Vanishing length expectation values means that the theory is becoming continuous, here dynamically in the originally discrete framework
Explaining the length threshold of polyglutamine aggregation
International Nuclear Information System (INIS)
De Los Rios, Paolo; Hafner, Marc; Pastore, Annalisa
2012-01-01
The existence of a length threshold, of about 35 residues, above which polyglutamine repeats can give rise to aggregation and to pathologies, is one of the hallmarks of polyglutamine neurodegenerative diseases such as Huntington’s disease. The reason why such a minimal length exists at all has remained one of the main open issues in research on the molecular origins of such classes of diseases. Following the seminal proposals of Perutz, most research has focused on the hunt for a special structure, attainable only above the minimal length, able to trigger aggregation. Such a structure has remained elusive and there is growing evidence that it might not exist at all. Here we review some basic polymer and statistical physics facts and show that the existence of a threshold is compatible with the modulation that the repeat length imposes on the association and dissociation rates of polyglutamine polypeptides to and from oligomers. In particular, their dramatically different functional dependence on the length rationalizes the very presence of a threshold and hints at the cellular processes that might be at play, in vivo, to prevent aggregation and the consequent onset of the disease. (paper)
Explaining the length threshold of polyglutamine aggregation
De Los Rios, Paolo; Hafner, Marc; Pastore, Annalisa
2012-06-01
The existence of a length threshold, of about 35 residues, above which polyglutamine repeats can give rise to aggregation and to pathologies, is one of the hallmarks of polyglutamine neurodegenerative diseases such as Huntington’s disease. The reason why such a minimal length exists at all has remained one of the main open issues in research on the molecular origins of such classes of diseases. Following the seminal proposals of Perutz, most research has focused on the hunt for a special structure, attainable only above the minimal length, able to trigger aggregation. Such a structure has remained elusive and there is growing evidence that it might not exist at all. Here we review some basic polymer and statistical physics facts and show that the existence of a threshold is compatible with the modulation that the repeat length imposes on the association and dissociation rates of polyglutamine polypeptides to and from oligomers. In particular, their dramatically different functional dependence on the length rationalizes the very presence of a threshold and hints at the cellular processes that might be at play, in vivo, to prevent aggregation and the consequent onset of the disease.
Nuclear reactor with scrammable part length rod
International Nuclear Information System (INIS)
Bevilacqua, F.
1979-01-01
A new part length rod is provided. It may be used to control xenon induced power oscillations but to contribute to shutdown reactivity when a rapid shutdown of the reactor is required. The part length rod consists of a control rod with three regions. The lower control region is a longer weaker active portion separated from an upper stronger shorter poison section by an intermediate section which is a relative non-absorber of neutrons. The combination of the longer weaker control section with the upper high worth poison section permits the part length rod of this to be scrammed into the core when a reactor shutdown is required but also permits the control rod to be used as a tool to control power distribution in both the axial and radial directions during normal operation
Resonance effects in neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Lynn, J.E.
1989-06-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-/angstrom/ wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs.
Aminophylline increases seizure length during electroconvulsive therapy.
Stern, L; Dannon, P N; Hirschmann, S; Schriber, S; Amytal, D; Dolberg, O T; Grunhaus, L
1999-12-01
Electroconvulsive therapy (ECT) is considered to be one of the most effective treatments for patients with major depression and persistent psychosis. Seizure characteristics probably determine the therapeutic effect of ECT; as a consequence, short seizures are accepted as one of the factors of poor outcome. During most ECT courses seizure threshold increases and seizure duration decreases. Methylxanthine preparations, caffeine, and theophylline have been used to prolong seizure duration. The use of aminophylline, more readily available than caffeine, has not been well documented. The objective of this study was to test the effects of aminophylline on seizure length. Fourteen drug-free patients with diagnoses of affective disorder or psychotic episode receiving ECT participated in this study. Seizure length was assessed clinically and per EEG. Statistical comparisons were done using paired t tests. A significant increase (p < 0.04) in seizure length was achieved and maintained on three subsequent treatments with aminophylline. No adverse events were noted from the addition of aminophylline.
Minimal Length Scale Scenarios for Quantum Gravity.
Hossenfelder, Sabine
2013-01-01
We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.
Extending electronic length frequency analysis in R
DEFF Research Database (Denmark)
Taylor, M. H.; Mildenberger, Tobias K.
2017-01-01
VBGF (soVBGF) requires a more intensive search due to two additional parameters. This work describes the implementation of two optimisation approaches ("simulated annealing" and "genetic algorithm") for growth function fitting using the open-source software "R." Using a generated LFQ data set......Electronic length frequency analysis (ELEFAN) is a system of stock assessment methods using length-frequency (LFQ) data. One step is the estimation of growth from the progression of LFQ modes through time using the von Bertalanffy growth function (VBGF). The option to fit a seasonally oscillating...... of the asymptotic length parameter (L-infinity) are found to have significant effects on parameter estimation error. An outlook provides context as to the significance of the R-based implementation for further testing and development, as well as the general relevance of the method for data-limited stock assessment....
Resonance effects in neutron scattering lengths
International Nuclear Information System (INIS)
Lynn, J.E.
1989-01-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-angstrom wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs
Minimal Length Scale Scenarios for Quantum Gravity
Directory of Open Access Journals (Sweden)
Sabine Hossenfelder
2013-01-01
Full Text Available We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.
Stride length: measuring its instantaneous value
International Nuclear Information System (INIS)
Campiglio, G C; Mazzeo, J R
2007-01-01
Human gait has been studied from different viewpoints: kinematics, dynamics, sensibility and others. Many of its characteristics still remain open to research, both for normal gait and for pathological gait. Objective measures of some of its most significant spatial/temporal parameters are important in this context. Stride length, one of these parameters, is defined as the distance between two consecutive contacts of one foot with ground. On this work we present a device designed to provide automatic measures of stride length. Its features make it particularly appropriate for the evaluation of pathological gait
Word length, set size, and lexical factors: Re-examining what causes the word length effect.
Guitard, Dominic; Gabel, Andrew J; Saint-Aubin, Jean; Surprenant, Aimée M; Neath, Ian
2018-04-19
The word length effect, better recall of lists of short (fewer syllables) than long (more syllables) words has been termed a benchmark effect of working memory. Despite this, experiments on the word length effect can yield quite different results depending on set size and stimulus properties. Seven experiments are reported that address these 2 issues. Experiment 1 replicated the finding of a preserved word length effect under concurrent articulation for large stimulus sets, which contrasts with the abolition of the word length effect by concurrent articulation for small stimulus sets. Experiment 2, however, demonstrated that when the short and long words are equated on more dimensions, concurrent articulation abolishes the word length effect for large stimulus sets. Experiment 3 shows a standard word length effect when output time is equated, but Experiments 4-6 show no word length effect when short and long words are equated on increasingly more dimensions that previous demonstrations have overlooked. Finally, Experiment 7 compared recall of a small and large neighborhood words that were equated on all the dimensions used in Experiment 6 (except for those directly related to neighborhood size) and a neighborhood size effect was still observed. We conclude that lexical factors, rather than word length per se, are better predictors of when the word length effect will occur. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Sighting optics including an optical element having a first focal length and a second focal length
Crandall, David Lynn [Idaho Falls, ID
2011-08-01
One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.
Cutting Whole Length or Partial Length of Internal Anal Sphincter in Managementof Fissure in Ano
Directory of Open Access Journals (Sweden)
Furat Shani Aoda
2017-12-01
Full Text Available A chronic anal fissure is a common painful perianal condition.The main operative procedure to treat this painful condition is a lateral internal sphincteretomy (LIS.The aim of study is to compare the outcome and complications of closed LIS up to the dentate line (whole length of internal sphincter or up to the fissure apex (partial length of internal sphincter in the treatment of anal fissure.It is a prospective comparativestudy including 100 patients with chronic fissure in ano. All patients assigned to undergo closed LIS. Those patients were randomly divided into two groups: 50 patients underwent LIS to the level of dentate line (whole length and other 50 patients underwent LIS to the level of fissure apex (partial length. Patients were followed up weekly in the 1st month, twice monthly in the second month then monthly for next 2 months and finally after 1 year. There was satisfactory relief of pain in all patients in both groups & complete healing of the fissure occurred. Regarding post operative incontinence no major degree of incontinence occur in both group but minor degree of incontinence persists In 7 patients after whole length LIS after one year. In conclusion, both whole length & partial length LIS associated with improvement of pain, good chance of healing but whole length LIS associated with more chance of long term flatus incontinence. Hence,we recommend partial length LIS as treatment forchronic anal fissure.
Neutron scattering lengths of 3He
International Nuclear Information System (INIS)
Alfimenkov, V.P.; Akopian, G.G.; Wierzbicki, J.; Govorov, A.M.; Pikelner, L.B.; Sharapov, E.I.
1976-01-01
The total neutron scattering cross-section of 3 He has been measured in the neutron energy range from 20 meV to 2 eV. Together with the known value of coherent scattering amplitude it leads to the two sts of n 3 He scattering lengths
Phonological length, phonetic duration and aphasia
Gilbers, D.G.; Bastiaanse, Y.R.M.; van der Linde, K.J.
1997-01-01
This study discusses an error type that is expected to occur in aphasics suffering from a phonological disorder, i.e. Wernicke's and conduction aphasics, but not in aphasics suffering from a phonetic disorder, i.e. Broca's aphasics. The critical notion is 'phonological length'. It will be argued
Information-theoretic lengths of Jacobi polynomials
Energy Technology Data Exchange (ETDEWEB)
Guerrero, A; Dehesa, J S [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, Granada (Spain); Sanchez-Moreno, P, E-mail: agmartinez@ugr.e, E-mail: pablos@ugr.e, E-mail: dehesa@ugr.e [Instituto ' Carlos I' de Fisica Teorica y Computacional, Universidad de Granada, Granada (Spain)
2010-07-30
The information-theoretic lengths of the Jacobi polynomials P{sup ({alpha}, {beta})}{sub n}(x), which are information-theoretic measures (Renyi, Shannon and Fisher) of their associated Rakhmanov probability density, are investigated. They quantify the spreading of the polynomials along the orthogonality interval [- 1, 1] in a complementary but different way as the root-mean-square or standard deviation because, contrary to this measure, they do not refer to any specific point of the interval. The explicit expressions of the Fisher length are given. The Renyi lengths are found by the use of the combinatorial multivariable Bell polynomials in terms of the polynomial degree n and the parameters ({alpha}, {beta}). The Shannon length, which cannot be exactly calculated because of its logarithmic functional form, is bounded from below by using sharp upper bounds to general densities on [- 1, +1] given in terms of various expectation values; moreover, its asymptotics is also pointed out. Finally, several computational issues relative to these three quantities are carefully analyzed.
Context quantization by minimum adaptive code length
DEFF Research Database (Denmark)
Forchhammer, Søren; Wu, Xiaolin
2007-01-01
Context quantization is a technique to deal with the issue of context dilution in high-order conditional entropy coding. We investigate the problem of context quantizer design under the criterion of minimum adaptive code length. A property of such context quantizers is derived for binary symbols....
Asymptotic Translation Length in the Curve Complex
Valdivia, Aaron D.
2013-01-01
We show that when the genus and punctures of a surface are directly proportional by some rational number the minimal asymptotic translation length in the curve complex has behavior inverse to the square of the Euler characteristic. We also show that when the genus is fixed and the number of punctures varies the behavior is inverse to the Euler characteristic.
Minimum Description Length Shape and Appearance Models
DEFF Research Database (Denmark)
Thodberg, Hans Henrik
2003-01-01
The Minimum Description Length (MDL) approach to shape modelling is reviewed. It solves the point correspondence problem of selecting points on shapes defined as curves so that the points correspond across a data set. An efficient numerical implementation is presented and made available as open s...
Hydrodynamic slip length as a surface property
Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.
2016-02-01
Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.
2010-04-01
... 23 Highways 1 2010-04-01 2010-04-01 false Length. 658.13 Section 658.13 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRUCK SIZE AND WEIGHT, ROUTE... Network or in transit between these highways and terminals or service locations pursuant to § 658.19. (b...
Link lengths and their growth powers
International Nuclear Information System (INIS)
Huh, Youngsik; No, Sungjong; Oh, Seungsang; Rawdon, Eric J
2015-01-01
For a certain infinite family F of knots or links, we study the growth power ratios of their stick number, lattice stick number, minimum lattice length and minimum ropelength compared with their minimum crossing number c(K) for every K∈F. It is known that the stick number and lattice stick number grow between the (1/2) and linear power of the crossing number, and minimum lattice length and minimum ropelength grow with at least the (3/4) power of crossing number (which is called the four-thirds power law). Furthermore, the minimal lattice length and minimum ropelength grow at most as O (c(K)[ln(c(K))] 5 ), but it is unknown whether any family exhibits superlinear growth. For any real number r between (1/2) and 1, we give an infinite family of non-splittable prime links in which the stick number and lattice stick number grow exactly as the rth power of crossing number. Furthermore for any real number r between (3/4) and 1, we give another infinite family of non-splittable prime links in which the minimum lattice length and minimum ropelength grow exactly as the rth power of crossing number. (paper)
Exciton diffusion length in narrow bandgap polymers
Mikhnenko, O.V.; Azimi, H.; Morana, M.; Blom, P.W.M.; Loi, M.A.
2012-01-01
We developed a new method to accurately extract the singlet exciton diffusion length in organic semiconductors by blending them with a low concentration of methanofullerene[6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The dependence of photoluminescence (PL) decay time on the fullerene
Scale Length of the Galactic Thin Disk
Indian Academy of Sciences (India)
tribpo
thin disk density scale length, hR, is rather short (2.7 ± 0.1 kpc). Key words. ... The 2MASS near infrared data provide, for the first time, deep star counts on a ... peaks allows to adjust the spatial extinction law in the model. ... probability that fi.
Jada, Balaji; Soitamo, Arto J; Siddiqui, Shahid Aslam; Murukesan, Gayatri; Aro, Eva-Mari; Salakoski, Tapio; Lehto, Kirsi
2014-01-01
Previously described transgenic tobacco lines express the full length infectious Tobacco mosaic virus (TMV) genome under the 35S promoter (Siddiqui et al., 2007. Mol Plant Microbe Interact, 20: 1489-1494). Through their young stages these plants exhibit strong resistance against both the endogenously expressed and exogenously inoculated TMV, but at the age of about 7-8 weeks they break into TMV infection, with typical severe virus symptoms. Infections with some other viruses (Potato viruses Y, A, and X) induce the breaking of the TMV resistance and lead to synergistic proliferation of both viruses. To deduce the gene functions related to this early resistance, we have performed microarray analysis of the transgenic plants during the early resistant stage, and after the resistance break, and also of TMV-infected wild type tobacco plants. Comparison of these transcriptomes to those of corresponding wild type healthy plants indicated that 1362, 1150 and 550 transcripts were up-regulated in the transgenic plants before and after the resistance break, and in the TMV-infected wild type tobacco plants, respectively, and 1422, 1200 and 480 transcripts were down-regulated in these plants, respectively. These transcriptome alterations were distinctly different between the three types of plants, and it appears that several different mechanisms, such as the enhanced expression of the defense, hormone signaling and protein degradation pathways contributed to the TMV-resistance in the young transgenic plants. In addition to these alterations, we also observed a distinct and unique gene expression alteration in these plants, which was the strong suppression of the translational machinery. This may also contribute to the resistance by slowing down the synthesis of viral proteins. Viral replication potential may also be suppressed, to some extent, by the reduction of the translation initiation and elongation factors eIF-3 and eEF1A and B, which are required for the TMV replication
String matching with variable length gaps
DEFF Research Database (Denmark)
Bille, Philip; Gørtz, Inge Li; Vildhøj, Hjalte Wedel
2012-01-01
primitive in computational biology applications. Let m and n be the lengths of P and T, respectively, and let k be the number of strings in P. We present a new algorithm achieving time O(nlogk+m+α) and space O(m+A), where A is the sum of the lower bounds of the lengths of the gaps in P and α is the total...... number of occurrences of the strings in P within T. Compared to the previous results this bound essentially achieves the best known time and space complexities simultaneously. Consequently, our algorithm obtains the best known bounds for almost all combinations of m, n, k, A, and α. Our algorithm...
Distance and Cable Length Measurement System
Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay
2009-01-01
A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169
Investigations on quantum mechanics with minimal length
International Nuclear Information System (INIS)
Chargui, Yassine
2009-01-01
We consider a modified quantum mechanics where the coordinates and momenta are assumed to satisfy a non-standard commutation relation of the form( X i , P j ) = iℎ(δ ij (1+βP 2 )+β'P i P j ). Such an algebra results in a generalized uncertainty relation which leads to the existence of a minimal observable length. Moreover, it incorporates an UV/IR mixing and non commutative position space. We analyse the possible representations in terms of differential operators. The latter are used to study the low energy effects of the minimal length by considering different quantum systems : the harmonic oscillator, the Klein-Gordon oscillator, the spinless Salpeter Coulomb problem, and the Dirac equation with a linear confining potential. We also discuss whether such effects are observable in precision measurements on a relativistic electron trapped in strong magnetic field.
Aberrant leukocyte telomere length in Birdshot Uveitis.
Vazirpanah, Nadia; Verhagen, Fleurieke H; Rothova, Anna; Missotten, Tom O A R; van Velthoven, Mirjam; Den Hollander, Anneke I; Hoyng, Carel B; Radstake, Timothy R D J; Broen, Jasper C A; Kuiper, Jonas J W
2017-01-01
Birdshot Uveitis (BU) is an archetypical chronic inflammatory eye disease, with poor visual prognosis, that provides an excellent model for studying chronic inflammation. BU typically affects patients in the fifth decade of life. This suggests that it may represent an age-related chronic inflammatory disease, which has been linked to increased erosion of telomere length of leukocytes. To study this in detail, we exploited a sensitive standardized quantitative real-time polymerase chain reaction to determine the peripheral blood leukocyte telomere length (LTL) in 91 genotyped Dutch BU patients and 150 unaffected Dutch controls. Although LTL erosion rates were very similar between BU patients and healthy controls, we observed that BU patients displayed longer LTL, with a median of log (LTL) = 4.87 (= 74131 base pair) compared to 4.31 (= 20417 base pair) in unaffected controls (PRTEL1. These findings suggest that BU is accompanied by significantly longer LTL.
Directory of Open Access Journals (Sweden)
B. Azzouz
2007-01-01
Full Text Available The textile fibre mixture as a multicomponent blend of variable fibres imposes regarding the proper method to predict the characteristics of the final blend. The length diagram and the fibrogram of cotton are generated. Then the length distribution, the length diagram, and the fibrogram of a blend of different categories of cotton are determined. The length distributions by weight of five different categories of cotton (Egyptian, USA (Pima, Brazilian, USA (Upland, and Uzbekistani are measured by AFIS. From these distributions, the length distribution, the length diagram, and the fibrogram by weight of four binary blends are expressed. The length parameters of these cotton blends are calculated and their variations are plotted against the mass fraction x of one component in the blend .These calculated parameters are compared to those of real blends. Finally, the selection of the optimal blends using the linear programming method, based on the hypothesis that the cotton blend parameters vary linearly in function of the components rations, is proved insufficient.
Quark ensembles with infinite correlation length
Molodtsov, S. V.; Zinovjev, G. M.
2014-01-01
By studying quark ensembles with infinite correlation length we formulate the quantum field theory model that, as we show, is exactly integrable and develops an instability of its standard vacuum ensemble (the Dirac sea). We argue such an instability is rooted in high ground state degeneracy (for 'realistic' space-time dimensions) featuring a fairly specific form of energy distribution, and with the cutoff parameter going to infinity this inherent energy distribution becomes infinitely narrow...
Summary of coherent neutron scattering length
International Nuclear Information System (INIS)
Rauch, H.
1981-07-01
Experimental values of neutron-nuclei bound scattering lengths for some 354 isotopes and elements and the various spin-states are compiled in a uniform way together with their error bars as quoted in the original literature. Recommended values are also given. The definitions of the relevant quantities presented in the data tables and the basic principles of measurements are explained in the introductory chapters. The data is also available on a magnetic tape
Asymptotic safety, emergence and minimal length
International Nuclear Information System (INIS)
Percacci, Roberto; Vacca, Gian Paolo
2010-01-01
There seems to be a common prejudice that asymptotic safety is either incompatible with, or at best unrelated to, the other topics in the title. This is not the case. In fact, we show that (1) the existence of a fixed point with suitable properties is a promising way of deriving emergent properties of gravity, and (2) there is a sense in which asymptotic safety implies a minimal length. In doing so we also discuss possible signatures of asymptotic safety in scattering experiments.
Minimal length uncertainty relation and ultraviolet regularization
Kempf, Achim; Mangano, Gianpiero
1997-06-01
Studies in string theory and quantum gravity suggest the existence of a finite lower limit Δx0 to the possible resolution of distances, at the latest on the scale of the Planck length of 10-35 m. Within the framework of the Euclidean path integral we explicitly show ultraviolet regularization in field theory through this short distance structure. Both rotation and translation invariance can be preserved. An example is studied in detail.
The Effective Coherence Length in Anisotropic Superconductors
International Nuclear Information System (INIS)
Polturak, E.; Koren, G.; Nesher, O
1999-01-01
If electrons are transmitted from a normal conductor(N) into a superconductor(S), common wisdom has it that the electrons are converted into Cooper pairs within a coherence length from the interface. This is true in conventional superconductors with an isotropic order parameter. We have established experimentally that the situation is rather different in high Tc superconductors having an anisotropic order parameter. We used epitaxial thin film S/N bilayers having different interface orientations in order to inject carriers from S into N along different directions. The distance to which these carriers penetrate were determined through their effect on the Tc of the bilayers. We found that the effective coherence length is 20A only along the a or b directions, while in other directions we find a length of 250dr20A out of plane, and an even larger value for in-plane, off high symmetry directions. These observations can be explained using the Blonder-Tinkham-Klapwijk model adapted to anisotropic superconductivity. Several implications of our results on outstanding problems with high Tc junctions will be discussed
FTO associations with obesity and telomere length.
Zhou, Yuling; Hambly, Brett D; McLachlan, Craig S
2017-09-01
This review examines the biology of the Fat mass- and obesity-associated gene (FTO), and the implications of genetic association of FTO SNPs with obesity and genetic aging. Notably, we focus on the role of FTO in the regulation of methylation status as possible regulators of weight gain and genetic aging. We present a theoretical review of the FTO gene with a particular emphasis on associations with UCP2, AMPK, RBL2, IRX3, CUX1, mTORC1 and hormones involved in hunger regulation. These associations are important for dietary behavior regulation and cellular nutrient sensing via amino acids. We suggest that these pathways may also influence telomere regulation. Telomere length (TL) attrition may be influenced by obesity-related inflammation and oxidative stress, and FTO gene-involved pathways. There is additional emerging evidence to suggest that telomere length and obesity are bi-directionally associated. However, the role of obesity risk-related genotypes and associations with TL are not well understood. The FTO gene may influence pathways implicated in regulation of TL, which could help to explain some of the non-consistent relationship between weight phenotype and telomere length that is observed in population studies investigating obesity.
Development of the Heated Length Correction Factor
International Nuclear Information System (INIS)
Park, Ho-Young; Kim, Kang-Hoon; Nahm, Kee-Yil; Jung, Yil-Sup; Park, Eung-Jun
2008-01-01
The Critical Heat Flux (CHF) on a nuclear fuel is defined by the function of flow channel geometry and flow condition. According to the selection of the explanatory variable, there are three hypotheses to explain CHF at uniformly heated vertical rod (inlet condition hypothesis, exit condition hypothesis, local condition hypothesis). For inlet condition hypothesis, CHF is characterized by function of system pressure, rod diameter, rod length, mass flow and inlet subcooling. For exit condition hypothesis, exit quality substitutes for inlet subcooling. Generally the heated length effect on CHF in exit condition hypothesis is smaller than that of other variables. Heated length is usually excluded in local condition hypothesis to describe the CHF with only local fluid conditions. Most of commercial plants currently use the empirical CHF correlation based on local condition hypothesis. Empirical CHF correlation is developed by the method of fitting the selected sensitive local variables to CHF test data using the multiple non-linear regression. Because this kind of method can not explain physical meaning, it is difficult to reflect the proper effect of complex geometry. So the recent CHF correlation development strategy of nuclear fuel vendor is making the basic CHF correlation which consists of basic flow variables (local fluid conditions) at first, and then the geometrical correction factors are compensated additionally. Because the functional forms of correction factors are determined from the independent test data which represent the corresponding geometry separately, it can be applied to other CHF correlation directly only with minor coefficient modification
Slip length crossover on a graphene surface
Energy Technology Data Exchange (ETDEWEB)
Liang, Zhi, E-mail: liangz3@rpi.edu [Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Keblinski, Pawel, E-mail: keplip@rpi.edu [Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
2015-04-07
Using equilibrium and non-equilibrium molecular dynamics simulations, we study the flow of argon fluid above the critical temperature in a planar nanochannel delimited by graphene walls. We observe that, as a function of pressure, the slip length first decreases due to the decreasing mean free path of gas molecules, reaches the minimum value when the pressure is close to the critical pressure, and then increases with further increase in pressure. We demonstrate that the slip length increase at high pressures is due to the fact that the viscosity of fluid increases much faster with pressure than the friction coefficient between the fluid and the graphene. This behavior is clearly exhibited in the case of graphene due to a very smooth potential landscape originating from a very high atomic density of graphene planes. By contrast, on surfaces with lower atomic density, such as an (100) Au surface, the slip length for high fluid pressures is essentially zero, regardless of the nature of interaction between fluid and the solid wall.
Short Rayleigh length free electron lasers
Directory of Open Access Journals (Sweden)
W. B. Colson
2006-03-01
Full Text Available Conventional free electron laser (FEL oscillators minimize the optical mode volume around the electron beam in the undulator by making the resonator Rayleigh length about one third to one half of the undulator length. This maximizes gain and beam-mode coupling. In compact configurations of high-power infrared FELs or moderate power UV FELs, the resulting optical intensity can damage the resonator mirrors. To increase the spot size and thereby reduce the optical intensity at the mirrors below the damage threshold, a shorter Rayleigh length can be used, but the FEL interaction is significantly altered. We model this interaction using a coordinate system that expands with the rapidly diffracting optical mode from the ends of the undulator to the mirrors. Simulations show that the interaction of the strongly focused optical mode with a narrow electron beam inside the undulator distorts the optical wave front so it is no longer in the fundamental Gaussian mode. The simulations are used to study how mode distortion affects the single-pass gain in weak fields, and the steady-state extraction in strong fields.
Correlated evolution of sternal keel length and ilium length in birds
Directory of Open Access Journals (Sweden)
Tao Zhao
2017-07-01
Full Text Available The interplay between the pectoral module (the pectoral girdle and limbs and the pelvic module (the pelvic girdle and limbs plays a key role in shaping avian evolution, but prior empirical studies on trait covariation between the two modules are limited. Here we empirically test whether (size-corrected sternal keel length and ilium length are correlated during avian evolution using phylogenetic comparative methods. Our analyses on extant birds and Mesozoic birds both recover a significantly positive correlation. The results provide new evidence regarding the integration between the pelvic and pectoral modules. The correlated evolution of sternal keel length and ilium length may serve as a mechanism to cope with the effect on performance caused by a tradeoff in muscle mass between the pectoral and pelvic modules, via changing moment arms of muscles that function in flight and in terrestrial locomotion.
Variational lower bound on the scattering length
International Nuclear Information System (INIS)
Rosenberg, L.; Spruch, L.
1975-01-01
The scattering length A characterizes the zero-energy scattering of one system by another. It was shown some time ago that a variational upper bound on A could be obtained using methods, of the Rayleigh-Ritz type, which are commonly employed to obtain upper bounds on energy eigenvalues. Here we formulate a method for obtaining a variational lower bound on A. Once again the essential idea is to express the scattering length as a variational estimate plus an error term and then to reduce the problem of bounding the error term to one involving bounds on energy eigenvalues. In particular, the variational lower bound on A is rigorously established provided a certin modified Hamiltonian can be shown to have no discrete states lying below the level of the continuum threshold. It is unfortunately true that necessary conditions for the existence of bound states are not available for multiparticle systems in general. However, in the case of positron-atom scattering the adiabatic approximation can be introduced as an (essentially) solvable comparison problem to rigorously establish the nonexistence of bound states of the modified Hamiltonian. It has recently been shown how the validity of the variational upper bound on A can be maintained when the target ground-state wave function is imprecisely known. Similar methods can be used to maintain the variational lower bound on A. Since the bound is variational, the error in the calculated scattering length will be of second order in the error in the wave function. The use of the adiabatic approximation in the present context places no limitation in principle on the accuracy achievable
Long Length Contaminated Equipment Maintenance Plan
International Nuclear Information System (INIS)
ESVELT, C.A.
2000-01-01
The purpose of this document is to provide the maintenance requirements of the Long Length Contaminated Equipment (LLCE) trailers and provide a basis for the maintenance frequencies selected. This document is applicable to the LLCE Receiver trailer and Transport trailer assembled by Mobilized Systems Inc. (MSI). Equipment used in conjunction with, or in support of, these trailers is not included. This document does not provide the maintenance requirements for checkout and startup of the equipment following the extended lay-up status which began in the mid 1990s. These requirements will be specified in other documentation
Track length estimation applied to point detectors
International Nuclear Information System (INIS)
Rief, H.; Dubi, A.; Elperin, T.
1984-01-01
The concept of the track length estimator is applied to the uncollided point flux estimator (UCF) leading to a new algorithm of calculating fluxes at a point. It consists essentially of a line integral of the UCF, and although its variance is unbounded, the convergence rate is that of a bounded variance estimator. In certain applications, involving detector points in the vicinity of collimated beam sources, it has a lower variance than the once-more-collided point flux estimator, and its application is more straightforward
Crack Length Detection by Digital Image Processing
DEFF Research Database (Denmark)
Lyngbye, Janus; Brincker, Rune
1990-01-01
It is described how digital image processing is used for measuring the length of fatigue cracks. The system is installed in a Personal Computer equipped with image processing hardware and performs automated measuring on plane metal specimens used in fatigue testing. Normally one can not achieve...... a resolution better then that of the image processing equipment. To overcome this problem an extrapolation technique is used resulting in a better resolution. The system was tested on a specimen loaded with different loads. The error σa was less than 0.031 mm, which is of the same size as human measuring...
Length Scales in Bayesian Automatic Adaptive Quadrature
Directory of Open Access Journals (Sweden)
Adam Gh.
2016-01-01
Full Text Available Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1–16 (2012] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule, mesoscopic (Simpson rule, and macroscopic (quadrature sums of high algebraic degrees of precision. Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.
Neutron chain length distributions in subcritical systems
International Nuclear Information System (INIS)
Nolen, S.D.; Spriggs, G.
1999-01-01
In this paper, the authors present the results of the chain-length distribution as a function of k in subcritical systems. These results were obtained from a point Monte Carlo code and a three-dimensional Monte Carlo code, MC++. Based on these results, they then attempt to explain why several of the common neutron noise techniques, such as the Rossi-α and Feynman's variance-to-mean techniques, are difficult to perform in highly subcritical systems using low-efficiency detectors
Sorghum cobalt analysis on not determined wave length with atomic ...
African Journals Online (AJOL)
This study was to know the better wave length on measuring cobalt content in forage sorghum hybrid (Sorghum bicolor) with an atomic absorption spectrophotometer. The analysis was on background correction mode with three wave lengths; 240.8, 240.7 (determined wave length or recommended wave length) and 240.6 ...
Cellular Mechanisms of Ciliary Length Control
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Jacob Keeling
2016-01-01
Full Text Available Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia.
Turbulence closure for mixing length theories
Jermyn, Adam S.; Lesaffre, Pierre; Tout, Christopher A.; Chitre, Shashikumar M.
2018-05-01
We present an approach to turbulence closure based on mixing length theory with three-dimensional fluctuations against a two-dimensional background. This model is intended to be rapidly computable for implementation in stellar evolution software and to capture a wide range of relevant phenomena with just a single free parameter, namely the mixing length. We incorporate magnetic, rotational, baroclinic, and buoyancy effects exactly within the formalism of linear growth theories with non-linear decay. We treat differential rotation effects perturbatively in the corotating frame using a novel controlled approximation, which matches the time evolution of the reference frame to arbitrary order. We then implement this model in an efficient open source code and discuss the resulting turbulent stresses and transport coefficients. We demonstrate that this model exhibits convective, baroclinic, and shear instabilities as well as the magnetorotational instability. It also exhibits non-linear saturation behaviour, and we use this to extract the asymptotic scaling of various transport coefficients in physically interesting limits.
Electron plasma oscillations at arbitrary Debye lengths
International Nuclear Information System (INIS)
Lehnert, B.
1990-12-01
A solution is presented for electron plasma oscillation in a thermalized homogeneous plasma, at arbitrary ratios between the Debye length λ D and the perturbation wave length λ. The limit λ D D >> λ corresponds to the free-streaming limit of strong kinetic phase-mixing due to large particle excursions. A strong large Debye distance (LDD) effect already appears when λ D > approx λ. The initial amplitude of the fluid-like contribution to the macroscopic density perturbation then becomes small as compared to the contribution from the free-streaming part. As a consequence, only a small fraction of the density perturbation remains after a limited number of kinetic damping times of the free-streaming part. The analysis further shows that a representation in terms of normal model of the form exp(-iωt) leads to amplitude factors of these modes which are related to each other and which depend on the combined free-streaming and fluid behaviour of the plasma. Consequently, these modes are coupled and cannot be treated as being independent of each other. (au)
ESTIMATION OF STATURE BASED ON FOOT LENGTH
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Vidyullatha Shetty
2015-01-01
Full Text Available BACKGROUND : Stature is the height of the person in the upright posture. It is an important measure of physical identity. Estimation of body height from its segments or dismember parts has important considerations for identifications of living or dead human body or remains recovered from disasters or other similar conditions. OBJECTIVE : Stature is an important indicator for identification. There are numerous means to establish stature and their significance lies in the simplicity of measurement, applicability and accuracy in prediction. Our aim of the study was to review the relationship between foot length and body height. METHODS : The present study reviews various prospective studies which were done to estimate the stature. All the measurements were taken by using standard measuring devices and standard anthropometric techniques. RESULTS : This review shows there is a correlation between stature and foot dimensions it is found to be positive and statistically highly significant. Prediction of stature was found to be most accurate by multiple regression analysis. CONCLUSIONS : Stature and gender estimation can be done by using foot measurements and stud y will help in medico - legal cases in establishing identity of an individual and this would be useful for Anatomists and Anthropologists to calculate stature based on foot length
Bunch Length Measurements using Coherent Radiation
Ischebeck, Rasmus; Barnes, Christopher; Blumenfeld, Ian; Clayton, Chris; Decker, Franz Josef; Deng, Suzhi; Hogan, Mark; Huang Cheng Kun; Iverson, Richard; Johnson, Devon K; Krejcik, Patrick; Lu, Wei; Marsh, Kenneth; Oz, Erdem; Siemann, Robert; Walz, Dieter
2005-01-01
The accelerating field that can be obtained in a beam-driven plasma wakefield accelerator depends on the current of the electron beam that excites the wake. In the E-167 experiment, a peak current above 10kA will be delivered at a particle energy of 28GeV. The bunch has a length of a few ten micrometers and several methods are used to measure its longitudinal profile. Among these, autocorrelation of coherent transition radiation (CTR) is employed. The beam passes a thin metallic foil, where it emits transition radiation. For wavelengths greater than the bunch length, this transition radiation is emitted coherently. This amplifies the long-wavelength part of the spectrum. A scanning Michelson interferometer is used to autocorrelate the CTR. However, this method requires the contribution of many bunches to build an autocorrelation trace. The measurement is influenced by the transmission characteristics of the vacuum window and beam splitter. We present here an analysis of materials, as well as possible layouts ...
Aberrant leukocyte telomere length in Birdshot Uveitis.
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Nadia Vazirpanah
Full Text Available Birdshot Uveitis (BU is an archetypical chronic inflammatory eye disease, with poor visual prognosis, that provides an excellent model for studying chronic inflammation. BU typically affects patients in the fifth decade of life. This suggests that it may represent an age-related chronic inflammatory disease, which has been linked to increased erosion of telomere length of leukocytes.To study this in detail, we exploited a sensitive standardized quantitative real-time polymerase chain reaction to determine the peripheral blood leukocyte telomere length (LTL in 91 genotyped Dutch BU patients and 150 unaffected Dutch controls.Although LTL erosion rates were very similar between BU patients and healthy controls, we observed that BU patients displayed longer LTL, with a median of log (LTL = 4.87 (= 74131 base pair compared to 4.31 (= 20417 base pair in unaffected controls (P<0.0001. The cause underpinning the difference in LTL could not be explained by clinical parameters, immune cell-subtype distribution, nor genetic predisposition based upon the computed weighted genetic risk score of genotyped validated variants in TERC, TERT, NAF1, OBFC1 and RTEL1.These findings suggest that BU is accompanied by significantly longer LTL.
Effective Debye length in closed nanoscopic systems: a competition between two length scales.
Tessier, Frédéric; Slater, Gary W
2006-02-01
The Poisson-Boltzmann equation (PBE) is widely employed in fields where the thermal motion of free ions is relevant, in particular in situations involving electrolytes in the vicinity of charged surfaces. The applications of this non-linear differential equation usually concern open systems (in osmotic equilibrium with an electrolyte reservoir, a semi-grand canonical ensemble), while solutions for closed systems (where the number of ions is fixed, a canonical ensemble) are either not appropriately distinguished from the former or are dismissed as a numerical calculation exercise. We consider herein the PBE for a confined, symmetric, univalent electrolyte and quantify how, in addition to the Debye length, its solution also depends on a second length scale, which embodies the contribution of ions by the surface (which may be significant in high surface-to-volume ratio micro- or nanofluidic capillaries). We thus establish that there are four distinct regimes for such systems, corresponding to the limits of the two parameters. We also show how the PBE in this case can be formulated in a familiar way by simply replacing the traditional Debye length by an effective Debye length, the value of which is obtained numerically from conservation conditions. But we also show that a simple expression for the value of the effective Debye length, obtained within a crude approximation, remains accurate even as the system size is reduced to nanoscopic dimensions, and well beyond the validity range typically associated with the solution of the PBE.
International Nuclear Information System (INIS)
Dimitrov, S.
1977-01-01
The effect of irradiation of White Leghorn eggs with ultraviolet rays on their embryonal development, egg hatchability, viability of hatched chicks and their liveweight, is studied. Irradiation length was 1, 3, 5, 10, 15, 20, 40 and 60 min in two experiments and 2, 4, 16 and 256 min in one trial. It was established that egg irradiation with ultraviolet rays affected positively egg hatchability and viability of the chicks, the irradiation effect being strongest in the range of 2 to 40 min. No significant difference was established between liveweight of chicks obtained from irradiated and nonirradiated eggs. It was further found that the length of incubation period was shortened by 2 to 5 hrs with increase in irradiation length over 5 min. (author)
Influence of recording length on reporting status
DEFF Research Database (Denmark)
Biltoft-Jensen, Anja Pia; Matthiessen, Jeppe; Fagt, Sisse
2009-01-01
: To investigate the impact of recording length on reporting status, expressed as the ratio between energy intake and calculated basal metabolic rate (EI/BMR), the percentage of consumers of selected food items and the number reported food items per meal and eating occasions per day. Methods: Data from two...... in a validation study and the Danish National Survey of Dietary Habits and Physical Activity 2000-2002, respectively. Both studies had a cross-sectional design. Volunteers and participants completed a pre-coded food diary every day for 7 consecutive days. BMR was predicted from equations. Results......: In the validation study, EI/BMR was significantly lower on 1st, 2nd and 3rd consecutive recording days compared to 4-7 recording days (P food items...
Bunch length and impedance measurements in SPEAR
International Nuclear Information System (INIS)
Bane, K.; Donald, M.; Hofmann, A.; Jowett, J.; Lockman, W.; Morton, P.; Stege, R.; Spence, W.; Wilson, P.
1988-05-01
Subsequent to an extensive smoothing of the vacuum chamber a comprehensive study of the SPEAR impedance was undertaken. Bunch length, synchrotron quadrupole mode frequency, and parasitic mode loss were measured as functions of beam current. The results showed that, although the gross longitudinal impedance had indeed been reduced, the 'capacitive' component had also decreased relative to the 'inductive'--to the extent that previously compensated potential well distortion now induced bunch lengthening at low currents, and the turbulent threshold had actually been lowered. A specially designed multi-cell disc-loaded 'capacitor' cavity was shown to be capable of removing this effect by restoring the original compensation. A model of the new SPEAR impedance is also obtained. 7 refs., 6 figs
Bunch length and impedance measurements in SPEAR
International Nuclear Information System (INIS)
Bane, K.; Donald, M.; Morton, P.; Stege, R.; Spence, W.; Wilson, P.; Hofmann, A.; Jowett, J.; Lockman, W.
1988-01-01
Subsequent to an extensive smoothing of the vacuum chamber a comprehensive study of the SPEAR impedance was undertaken. Bunch length, synchrotron quadrupole mode frequency, and parasitic mode loss were measured as functions of beam current. This paper shows that although the gross longitudinal impedance had indeed been reduced, the capacitive component had also decreased relative to the inductive - to the extent that previously compensated potential well distortion now induced bunch lengthening at low currents, and the turbulent threshold had actually been lowered. A specially designed multi-cell disc-loaded capacitor cavity was shown to be capable of removing this effect by restoring the original compensation. A model of the new SPEAR impedance is also obtained
Quark ensembles with the infinite correlation length
Zinov'ev, G. M.; Molodtsov, S. V.
2015-01-01
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.
Quark ensembles with the infinite correlation length
International Nuclear Information System (INIS)
Zinov’ev, G. M.; Molodtsov, S. V.
2015-01-01
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble
Quark ensembles with the infinite correlation length
Energy Technology Data Exchange (ETDEWEB)
Zinov’ev, G. M. [National Academy of Sciences of Ukraine, Bogoliubov Institute for Theoretical Physics (Ukraine); Molodtsov, S. V., E-mail: molodtsov@itep.ru [Joint Institute for Nuclear Research (Russian Federation)
2015-01-15
A number of exactly integrable (quark) models of quantum field theory with the infinite correlation length have been considered. It has been shown that the standard vacuum quark ensemble—Dirac sea (in the case of the space-time dimension higher than three)—is unstable because of the strong degeneracy of a state, which is due to the character of the energy distribution. When the momentum cutoff parameter tends to infinity, the distribution becomes infinitely narrow, leading to large (unlimited) fluctuations. Various vacuum ensembles—Dirac sea, neutral ensemble, color superconductor, and BCS state—have been compared. In the case of the color interaction between quarks, the BCS state has been certainly chosen as the ground state of the quark ensemble.
Tolerance at arm's length: the Dutch experience.
Schuijer, J
1990-01-01
With respect to pedophilia and the age of consent, the Netherlands warrants special attention. Although pedophilia is not as widely accepted in the Netherlands as sometimes is supposed, developments in the judicial practice showed a growing reservedness. These developments are a spin-off of related developments in Dutch society. The tolerance in the Dutch society has roots that go far back in history and is also a consequence of the way this society is structured. The social changes of the sixties and seventies resulted in a "tolerance at arm's length" for pedophiles, which proved to be deceptive when the Dutch government proposed to lower the age of consent in 1985. It resulted in a vehement public outcry. The prevailing sex laws have been the prime target of protagonists of pedophile emancipation. Around 1960, organized as a group, they started to undertake several activities. In the course of their existence, they came to redefine the issue of pedophilia as one of youth emancipation.
Burnout among physiotherapists and length of service
Directory of Open Access Journals (Sweden)
Zbigniew Śliwiński
2014-04-01
Full Text Available Objectives: The aim of this study was to identify factors that contribute to the development of burnout among physiotherapists with different length of service in physiotherapy. Material and Methods: The following research tools were used to study burnout: the Life Satisfaction Questionnaire (LSQ, based on FLZ (Fragebogen zur Lebenszufriedenheit by Frahrenberg, Myrtek, Schumacher, and Brähler; the Burnout Scale Inventory (BSI by Steuden and Okła; and an ad hoc questionnaire to collect socio-demographic data. The survey was anonymous and voluntary and involved a group of 200 active physiotherapists working in Poland. Results: A statistical analysis revealed significant differences in overall life satisfaction between length-of-service groups (p = 0.03. Physiotherapists with more than 15 years of service reported greater satisfaction than those with less than 5 years and between 5 and 15 years of service. The results suggest that burnout in those with 5-15 years of service is higher in physiotherapists working in health care centers and increases with age and greater financial satisfaction, while it decreases with greater satisfaction with friend and family relations and greater satisfaction with one's work and profession. In those with more than 15 years of service, burnout increases in the case of working in a setting other than a health care or educational center and decreases with greater satisfaction with one's work and profession. Conclusions: Job satisfaction and a satisfying family life prevent burnout among physiotherapists with 5-15 years of service in the profession. Financial satisfaction, age and being employed in health care may cause burnout among physiotherapists with 5-15 years of service. Physiotherapists with more than 15 years of service experience more burnout if they work in a setting other than a health care or educational center and less burnout if they are satisfied with their profession.
Father Loss and Child Telomere Length.
Mitchell, Colter; McLanahan, Sara; Schneper, Lisa; Garfinkel, Irv; Brooks-Gunn, Jeanne; Notterman, Daniel
2017-08-01
Father loss during childhood has negative health and behavioral consequences, but the biological consequences are unknown. Our goal was to examine how father loss (because of separation and/or divorce, death, or incarceration) is associated with cellular function as estimated by telomere length. Data come from the 9-year follow-up of the Fragile Families and Child Wellbeing Study, a birth cohort study of children in 20 large American cities ( N = 2420). Principal measures are as follows: salivary telomere length (sTL), mother reports of father loss, and polymorphisms in genes related to serotonergic and dopaminergic signaling. At 9 years of age, children with father loss have significantly shorter telomeres (14% reduction). Paternal death has the largest association (16%), followed by incarceration (10%), and separation and/or divorce (6%). Changes in income partially mediate these associations (95% mediation for separation and/or divorce, 30% for incarceration, and 25% for death). Effects are 40% greater for boys and 90% greater for children with the most reactive alleles of the serotonin transporter genes when compared with those with the least reactive alleles. No differences were found by age at father loss or a child's race/ethnicity. Father loss has a significant association with children's sTL, with the death of a father showing the largest effect. Income loss explains most of the association between child sTL and separation and/or divorce but much less of the association with incarceration or death. This underscores the important role of fathers in the care and development of children and supplements evidence of the strong negative effects of parental incarceration. Copyright © 2017 by the American Academy of Pediatrics.
Concept of formation length in radiation theory
International Nuclear Information System (INIS)
Baier, V.N.; Katkov, V.M.
2005-01-01
The features of electromagnetic processes are considered which connected with finite size of space region in which final particles (photon, electron-positron pair) are formed. The longitudinal dimension of the region is known as the formation length. If some external agent is acting on an electron while traveling this distance the emission process can be disrupted. There are different agents: multiple scattering of projectile, polarization of a medium, action of external fields, etc. The theory of radiation under influence of the multiple scattering, the Landau-Pomeranchuk-Migdal (LPM) effect, is presented. The probability of radiation is calculated with an accuracy up to 'next to leading logarithm' and with the Coulomb corrections taken into account. The integral characteristics of bremsstrahlung are given, it is shown that the effective radiation length increases due to the LPM effect at high energy. The LPM effect for pair creation is also presented. The multiple scattering influences also on radiative corrections in a medium (and an external field too) including the anomalous magnetic moment of an electron and the polarization tensor as well as coherent scattering of a photon in a Coulomb field. The polarization of a medium alters the radiation probability in soft part of spectrum. Specific features of radiation from a target of finite thickness include: the boundary photon emission, interference effects for thin target, multi-photon radiation. The theory predictions are compared with experimental data obtained at SLAC and CERN SPS. For electron-positron colliding beams following items are discussed: the separation of coherent and incoherent mechanisms of radiation, the beam-size effect in bremsstrahlung, coherent radiation and mechanisms of electron-positron creation
SURVIVAL ANALYSIS AND LENGTH-BIASED SAMPLING
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Masoud Asgharian
2010-12-01
Full Text Available When survival data are colleted as part of a prevalent cohort study, the recruited cases have already experienced their initiating event. These prevalent cases are then followed for a fixed period of time at the end of which the subjects will either have failed or have been censored. When interests lies in estimating the survival distribution, from onset, of subjects with the disease, one must take into account that the survival times of the cases in a prevalent cohort study are left truncated. When it is possible to assume that there has not been any epidemic of the disease over the past period of time that covers the onset times of the subjects, one may assume that the underlying incidence process that generates the initiating event times is a stationary Poisson process. Under such assumption, the survival times of the recruited subjects are called “lengthbiased”. I discuss the challenges one is faced with in analyzing these type of data. To address the theoretical aspects of the work, I present asymptotic results for the NPMLE of the length-biased as well as the unbiased survival distribution. I also discuss estimating the unbiased survival function using only the follow-up time. This addresses the case that the onset times are either unknown or known with uncertainty. Some of our most recent work and open questions will be presented. These include some aspects of analysis of covariates, strong approximation, functional LIL and density estimation under length-biased sampling with right censoring. The results will be illustrated with survival data from patients with dementia, collected as part of the Canadian Study of Health and Aging (CSHA.
Directory of Open Access Journals (Sweden)
Goh Li Teng
2011-03-01
Full Text Available The Thumb Rule of Leonardo da Vinci states that many proportions of the face show relationship with the length of thumb which is measured from the proximal tip of the proximal phalanx to the distal tip of the distal phalanx. Previous studies have shown that the length of the vertical dimension of occlusion (VDO is similar to the length of thumb of the Caucasoid race. The purpose of this study is to determine whether the length of VDO have correlations with the length of thumb among those of the Mongoloid race. This study took a survey method with the analytical cross-sectional approach. A total of 80 students of Faculty of Dentistry who have fulfilled all population criteria were randomly chosen to measure the length of VDO and the length of the thumb. Results analyzed with Student's t-test statistic revealed that there was a significant difference between males and females in the length of VDO and the length of the thumb, however, there was no significant difference between the length of VDO and the length of the thumb. There were very strong correlations (P<0.05 between the length of VDO and the length of the thumb. As a conclusion, the length of thumb can be suggested as an objective method to determine the length of VDO in this population.
Lifetime and Path Length of the Virtual Particle
International Nuclear Information System (INIS)
Lyuboshitz, V.L.; Lyuboshitz, V.V.
2005-01-01
The concepts of the lifetime and path length of a virtual particle are introduced. It is shown that, near the mass surface of the real particle, these quantities constitute a 4-vector. At very high energies, the virtual particle can propagate over considerable (even macroscopic) distances. The formulas for the lifetime and path length of an ultrarelativistic virtual electron in the process of bremsstrahlung in the Coulomb field of a nucleus are obtained. The lifetime and path length of the virtual photon at its conversion into an electron-positron pair are discussed. The connection between the path length of the virtual particle and the coherence length (formation length) is analyzed
Length Matters: Informational Load in Ambiguity Resolution
Directory of Open Access Journals (Sweden)
Barbara Hemforth
2013-07-01
Full Text Available In this paper, we will compare prosodic and pragmatic approaches to the role of constituent length in attachment ambiguities. Lengthening a constituent affects its informativity: longer constituents are usually less predictable (Levy & Florian, 2007 and demand a higher processing load than shorter ones (Almor, 1999. Following neo-Gricean accounts (Levinson, 1987 and 1991, increased informational load needs to be justified. This justification is achieved more easily when the long constituent conveys new information and when it relates to central elements of the utterance. Informational load is, however, not a simple question of length in numbers of characters or syllables but more likely a question of amount of information. In three off-line experiments using a cloze task, we will compare the effect of lengthening ambiguous prepositional phrases as in [1a/b/c] either by lengthening a city name or by adding information about the city. We will show that only lengthening by adding information increases attachment to a more central element of the utterance. These results will be discussed based on prosodic and pragmatic factors explaining the role of constituent length for attachment ambiguities.[1] Peter met the doctor of the lawyer from a. Apt. / b. Aix-en-Provence / c. the beautiful city of Apt.Dans cet article, nous comparons une approche prosodique avec une approche pragmatique pour rendre compte des effets de la longueur des constituants dans les ambigüités d’attachement. Augmenter la longueur d’un constituant a des conséquences sur l’information qu’il véhicule : plus un constituant est long et moins il est prédictible (Levy et Florian, 2007 et plus son coût de traitement augmente (Almor, 1999. Suivant les principes néo-gricéens (Levinson, 1987 et 1991, augmenter le poids informationnel doit être justifié. Cette justification est plus facilement satisfaite lorsqu’un constituant long véhicule une information
Effect of canal length and curvature on working length alteration with WaveOne reciprocating files.
Berutti, Elio; Chiandussi, Giorgio; Paolino, Davide Salvatore; Scotti, Nicola; Cantatore, Giuseppe; Castellucci, Arnaldo; Pasqualini, Damiano
2011-12-01
This study evaluated the working length (WL) modification after instrumentation with WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland) reciprocating files and the incidence of overinstrumentation in relation to the initial WL. Thirty-two root canals of permanent teeth were used. The angles of curvature of the canals were calculated on digital radiographs. The initial WL with K-files was transferred to the matched WaveOne Primary reciprocating files. After glide paths were established with PathFile (Dentsply Maillefer, Ballaigues, Switzerland), canals were shaped with WaveOne Primary referring to the initial WL. The difference between the postinstrumentation canal length and the initial canal length was analyzed by using a fiberoptic inspection microscope. Data were analyzed with a balanced 2-way factorial analysis of variance (P < .05). Referring to the initial WL, 24 of 32 WaveOne Primary files projected beyond the experimental apical foramen (minimum-maximum, 0.14-0.76 mm). A significant decrease in the canal length after instrumentation (95% confidence interval ranging from -0.34 mm to -0.26 mm) was detected. The canal curvature significantly influenced the WL variation (F(1) = 30.65, P < .001). The interaction between the initial canal length and the canal curvature was statistically significant (F(2) = 4.38, P = .014). Checking the WL before preparation of the apical third of the root canal is recommended when using the new WaveOne NiTi single-file system. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
Spectral interferometric length measurement and tomography
International Nuclear Information System (INIS)
Pinkl, W.
1998-01-01
This work presents a new method for optical length measurement using the principles of spectral interferometry. Results of thickness measurements on glass plates, the human cornea in vivo and human finger and toe nails in vivo and in vitro are discussed. It could be demonstrated that the absorption coefficient of red and green ink can be measured depth sensitive. Another chapter describes a new technique to measure a thickness profile of a sample within the illuminating beam. It could be demonstrated that a thickness profile over a distance of a few millimeters can be measured with one single measurement. At the Institute of Medical Physics of the University of Vienna a method to measure intraocular distances by the means of interferometry has been developed during the last ten years. Basing on this method (dual beam interferometry) an optical in vivo tomography experiment could be established. A thickness map of the retina of a human eye in vivo can be easily measured. The dual beam technique uses a Michelson interferometer with a moving mirror to adjust the length of the interferometer arms. The mirror is moved by a stepper motor. This movement induces vibrations, misalignment and other disadvantages. So mechanically moved parts as reasons for possible errors should be eliminated. This work shows one possible solution - using the principle of spectral interferometry. A spectral interferometry experiment is a static experiment, no moving parts are used. A spectral interferometry experiment has been used to measure the thickness of glass plates and stacks of glass plates. Using two light sources of different wavelengths spectral absorption properties of a sample can be measured depth sensitive. This could be demonstrated with stacks of glass plates and the use of red and green ink between two plates. The obtained results are compared to the results of a computer simulation. To demonstrate the ability of spectral interferometry to measure the thickness of biologic
Correlation length of magnetosheath fluctuations: Cluster statistics
Directory of Open Access Journals (Sweden)
O. Gutynska
2008-09-01
Full Text Available Magnetosheath parameters are usually described by gasdynamic or magnetohydrodynamic (MHD models but these models cannot account for one of the most important sources of magnetosheath fluctuations – the foreshock. Earlier statistical processing of a large amount of magnetosheath observations has shown that the magnetosheath magnetic field and plasma flow fluctuations downstream of the quasiparallel shock are much larger than those at the opposite flank. These studies were based on the observations of a single spacecraft and thus they could not provide full information on propagation of the fluctuations through the magnetosheath.
We present the results of a statistical survey of the magnetosheath magnetic field fluctuations using two years of Cluster observations. We discuss the dependence of the cross-correlation coefficients between different spacecraft pairs on the orientation of the separation vector with respect to the average magnetic field and plasma flow vectors and other parameters. We have found that the correlation length does not exceed ~1 R_{E} in the analyzed frequency range (0.001–0.125 Hz and does not depend significantly on the magnetic field or plasma flow direction. A close connection of cross-correlation coefficients computed in the magnetosheath with the cross-correlation coefficients between a solar wind monitor and a magnetosheath spacecraft suggests that solar wind structures persist on the background of magnetosheath fluctuations.
Telomere length maintenance--an ALTernative mechanism.
Royle, N J; Foxon, J; Jeyapalan, J N; Mendez-Bermudez, A; Novo, C L; Williams, J; Cotton, V E
2008-01-01
The Alternative Lengthening of Telomeres (ALT) mechanism is utilised by approximately 10% of human tumours and a higher proportion of some types of sarcomas. ALT+ cell lines and tumours show heterogeneous telomere length, extra-chromosomal circular and linear telomeric DNA, ALT associated promyelocytic bodies (APBs), a high frequency of post-replication exchanges in telomeres (designated as telomere-sister chromatid exchanges, T-SCE) and high instability at a GC-rich minisatellite, MS32 (D1S8). It is clear that there is a link between the minisatellite instability and the mechanism that underpins ALT, however currently the nature of this relationship is uncertain. Single molecule analysis of telomeric DNA from ALT+ cell lines and tumours has revealed complex telomere mutations that have not been seen in cell lines or tumours that express telomerase. These complex telomere mutations cannot be explained by T-SCE but must arise by another inter-molecular process. The break-induced replication (BIR) model that may explain the observed high frequency of T-SCE and the presence of complex telomere mutations is reviewed. Copyright 2008 S. Karger AG, Basel.
Full length prototype SSC dipole test results
International Nuclear Information System (INIS)
Strait, J.; Brown, B.C.; Carson, J.
1987-01-01
Results are presented from tests of the first full length prototype SSC dipole magnet. The cryogenic behavior of the magnet during a slow cooldown to 4.5K and a slow warmup to room temperature has been measured. Magnetic field quality was measured at currents up to 2000 A. Averaged over the body field all harmonics with the exception of b 2 and b 8 are at or within the tolerances specified by the SSC Central Design Group. (The values of b 2 and b 8 result from known design and construction defects which will be be corrected in later magnets.) Using an NMR probe the average body field strength is measured to be 10.283 G/A with point to point variations on the order of one part in 1000. Data are presented on quench behavior of the magnet up to 3500 A (approximately 55% of full field) including longitudinal and transverse velocities for the first 250 msec of the quench
Relation between axial length and ocular parameters
Directory of Open Access Journals (Sweden)
Xue-Qiu Yang
2013-09-01
Full Text Available AIM: To investigatethe relation between axial length(AL, age and ocular parameters.METHODS: A total of 360 subjects(360 eyeswith emmetropia or myopia were recruited. Refraction, center corneal thickness(CCT, AL, intraocular pressure(IOPwere measured by automatic-refractor, Pachymeter, A-mode ultrasound and non-contact tonometer, respectively. Corneal curvature(CC, anterior chamber depth(ACDand white-to-white distance(WWDwere measured by Orbscan II. Three dimensional frequency domain coherent optical tomography(3D-OCTwas used to examine the retinal nerve fiber layer thickness(RNFLT. The Pearson correlation coefficient(rand multiple regression analysis were performed to evaluate the relationship between AL, age and ocular parameters.RESULTS: The average AL was 24.15±1.26mm. With elongation of the AL, spherical equivalent(SE(r=-0.742,Pr=-0.395, Pr=-0.374, Pr=0.411, Pr=0.099, P=0.060and WWD(r=0.061, P=0.252. There was also a significant correlation between AL and age(P=0.001, SE(PPPCONCLUSION: In longer eyes, there is a tendency toward myopia, a flatter cornea, a deeper ACD and a thinner RNFLT. Age is an influencing factor for the AL as well.
Correlation length of magnetosheath fluctuations: Cluster statistics
Directory of Open Access Journals (Sweden)
O. Gutynska
2008-09-01
Full Text Available Magnetosheath parameters are usually described by gasdynamic or magnetohydrodynamic (MHD models but these models cannot account for one of the most important sources of magnetosheath fluctuations – the foreshock. Earlier statistical processing of a large amount of magnetosheath observations has shown that the magnetosheath magnetic field and plasma flow fluctuations downstream of the quasiparallel shock are much larger than those at the opposite flank. These studies were based on the observations of a single spacecraft and thus they could not provide full information on propagation of the fluctuations through the magnetosheath. We present the results of a statistical survey of the magnetosheath magnetic field fluctuations using two years of Cluster observations. We discuss the dependence of the cross-correlation coefficients between different spacecraft pairs on the orientation of the separation vector with respect to the average magnetic field and plasma flow vectors and other parameters. We have found that the correlation length does not exceed ~1 RE in the analyzed frequency range (0.001–0.125 Hz and does not depend significantly on the magnetic field or plasma flow direction. A close connection of cross-correlation coefficients computed in the magnetosheath with the cross-correlation coefficients between a solar wind monitor and a magnetosheath spacecraft suggests that solar wind structures persist on the background of magnetosheath fluctuations.
Information Cost, Memory Length and Market Instability.
Diks, Cees; Li, Xindan; Wu, Chengyao
2018-07-01
In this article, we study the instability of a stock market with a modified version of Diks and Dindo's (2008) model where the market is characterized by nonlinear interactions between informed traders and uninformed traders. In the interaction of heterogeneous agents, we replace the replicator dynamics for the fractions by logistic strategy switching. This modification makes the model more suitable for describing realistic price dynamics, as well as more robust with respect to parameter changes. One goal of our paper is to use this model to explore if the arrival of new information (news) and investor behavior have an effect on market instability. A second, related, goal is to study the way markets absorb new information, especially when the market is unstable and the price is far from being fully informative. We find that the dynamics become locally unstable and prices may deviate far from the fundamental price, routing to chaos through bifurcation, with increasing information costs or decreasing memory length of the uninformed traders.
Molecular markers. Amplified fragment length polymorphism
Directory of Open Access Journals (Sweden)
Pržulj Novo
2005-01-01
Full Text Available Amplified Fragment Length Polymorphism molecular markers (AFLPs has been developed combining procedures of RFLPs and RAPDs molekular markers, i.e. the first step is restriction digestion of the genomic DNA that is followed by selective amplification of the restricted fragments. The advantage of the AFLP technique is that it allows rapid generation of a large number of reproducible markers. The reproducibility of AFLPs markers is assured by the use of restriction site-specific adapters and adapter-specific primers for PCR reaction. Only fragments containing the restriction site sequence plus the additional nucleotides will be amplified and the more selected nucleotides added on the primer sequence the fewer the number of fragments amplified by PCR. The amplified products are normally separated on a sequencing gel and visualized after exposure to X-ray film or by using fluorescent labeled primers. AFLP shave proven to be extremely proficient in revealing diversity at below the species level. A disadvantage of AFLP technique is that AFLPs are essentially a dominant marker system and not able to identify heterozygotes.
Debye screening length effects of nanostructured materials
Ghatak, Kamakhya Prasad
2014-01-01
This monograph solely investigates the Debye Screening Length (DSL) in semiconductors and their nano-structures. The materials considered are quantized structures of non-linear optical, III-V, II-VI, Ge, Te, Platinum Antimonide, stressed materials, Bismuth, GaP, Gallium Antimonide, II-V and Bismuth Telluride respectively. The DSL in opto-electronic materials and their quantum confined counterparts is studied in the presence of strong light waves and intense electric fields on the basis of newly formulated electron dispersion laws that control the studies of such quantum effect devices. The suggestions for the experimental determination of 2D and 3D DSL and the importance of measurement of band gap in optoelectronic materials under intense built-in electric field in nano devices and strong external photo excitation (for measuring photon induced physical properties) have also been discussed in this context. The influence of crossed electric and quantizing magnetic fields on the DSL and the DSL in heavily doped ...
Performance of RC columns with partial length corrosion
International Nuclear Information System (INIS)
Wang Xiaohui; Liang Fayun
2008-01-01
Experimental and analytical studies on the load capacity of reinforced concrete (RC) columns with partial length corrosion are presented, where only a fraction of the column length was corroded. Twelve simply supported columns were eccentrically loaded. The primary variables were partial length corrosion in tensile or compressive zone and the corrosion level within this length. The failure of the corroded column occurs in the partial length, mainly developed from or located nearby or merged with the longitudinal corrosion cracks. For RC column with large eccentricity, load capacity of the column is mainly influenced by the partial length corrosion in tensile zone; while for RC column with small eccentricity, load capacity of the column greatly decreases due to the partial length corrosion in compressive zone. The destruction of the longitudinally mechanical integrality of the column in the partial length leads to this great reduction of the load capacity of the RC column
Radiographic versus electronic root canal working length determination
Directory of Open Access Journals (Sweden)
Lumnije Kqiku
2011-01-01
Conclusions: The present ex vivo study showed that electronic root canal working length determination is not superior to radiographic methods. Both methods provided a good performance in determining the root canal working length.
Imprisonment length and post-prison employment prospects
Ramakers, Anke; Apel, Robert; Nieuwbeerta, Paul; Dirkzwager, Anja; Van Wilsem, Johan
2014-01-01
This study considers the relationship between imprisonment length and employment outcomes. The data are a unique prospective, longitudinal study of Dutch pretrial detainees (N = 702). All subjects thus experience prison confinement of varying lengths, although the durations are relatively short
Optical Arc-Length Sensor For TIG Welding
Smith, Matthew A.
1990-01-01
Proposed subsystem of tungsten/inert-gas (TIG) welding system measures length of welding arc optically. Viewed by video camera, in one of three alternative optical configurations. Length of arc measured instead of inferred from voltage.
Lake Basin Fetch and Maximum Length/Width
Minnesota Department of Natural Resources — Linear features representing the Fetch, Maximum Length and Maximum Width of a lake basin. Fetch, maximum length and average width are calcuated from the lake polygon...
Wijlens, G.M.; Erkner, A.; Mars, M.; Graaf, de C.
2015-01-01
Background: A long oral exposure to food and a high-energy density of food are shown to increase satiety feelings. The effect of energy density is predominantly caused by an inhibition of gastric emptying. It is hypothesized that prolonging oral exposure may have an additional effect on this
Wijlens, Anne G M; Erkner, Alfrun; Mars, Monica; de Graaf, Cees
2015-02-01
A long oral exposure to food and a high-energy density of food have been shown to increase satiety feelings. The effect of energy density is predominantly caused by an inhibition of gastric emptying. It is hypothesized that prolonging oral exposure may have an additional effect on this inhibition of gastric emptying. However, little human data are available to support this hypothesis. The objective was to assess the effect of the duration of oral exposure to food on gastric emptying rate of gastric loads (GLs) low and high in energy density and on satiety feelings. Twenty-six healthy men [mean ± SD age: 22 ± 3 y; BMI (in kg/m(2)): 23 ± 1] participated in a randomized crossover trial with 4 treatments and a control. Treatments consisted of either 1- or 8-min modified sham feeding (MSF) of cake, and a GL of either 100 or 700 kcal infused in the stomach via a nasogastric tube (500 mL, 62.5 mL/min). The control consisted of no MSF and a GL of 500 mL of water. Gastric emptying rate was assessed with a (13)C breath test. Breath samples and satiety feelings were collected at fixed time points until 90 min after start of the treatment. Gastric emptying rate and satiety feelings were not affected by duration of MSF (P ≥ 0.27). However, the 700-kcal GL treatments slowed gastric emptying [41% lower area under the curve (AUC)] and increased satiety feelings (22-31% higher AUC) compared with the 100-kcal GL treatments (P men. However, prolonging oral exposure to food did not have an additional effect. This study provides more insight in satiety regulation. This trial was registered at trialregister.nl as NTR3601. © 2015 American Society for Nutrition.
Huhn, Oliver; Rhein, Monika; Hoppema, Mario; van Heuven, Steven
We use a 27 year long time series of repeated transient tracer observations to investigate the evolution of the ventilation time scales and the related content of anthropogenic carbon (C-ant) in deep and bottom water in the Weddell Sea. This time series consists of chlorofluorocarbon (CFC)
Kucharewicz, Weronika; Distelfeld, Assaf; Bilger, Wolfgang; Müller, Maren; Munné-Bosch, Sergi; Hensel, Götz; Krupinska, Karin
2017-02-01
WHIRLY1 in barley was isolated as a potential regulator of the senescence-associated gene HvS40. In order to investigate whether the plastid-nucleus-located DNA/RNA-binding protein WHIRLY1 plays a role in regulation of leaf senescence, primary foliage leaves from transgenic barley plants with an RNAi-mediated knockdown of the WHIRLY1 gene were characterized by typical senescence parameters, namely pigment contents, function and composition of the photosynthetic apparatus, as well as expression of selected genes known to be either down- or up-regulated during leaf senescence. When the plants were grown at low light intensity, senescence progression was similar between wild-type and RNAi-W1 plants. Likewise, dark-induced senescence of detached leaves was not affected by reduction of WHIRLY1. When plants were grown at high light intensity, however, senescence was induced prematurely in wild-type plants but was delayed in RNAi-W1 plants. This result suggests that WHIRLY1 plays a role in light sensing and/or stress communication between chloroplasts and the nucleus. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.
International Nuclear Information System (INIS)
Borak, T.B.; Stinchcomb, T.G.
1979-01-01
A rapid system has been developed for computing charged-particle distributions generated in tissue by any neutron spectra less than 4 MeV. Oxygen and carbon recoils were derived from R-matrix theory, and hydrogen recoils were obtained from cross-section evaluation. Application to two quite different fission-neutron spectra demonstrates the flexibility of this method for providing spectral details of the different types of charged-particle recoils. Comparisons have been made between calculations and measurements of event-size distributions for a sphere of tissue 1 μm in diameter irradiated by these two neutron spectra. LET distributions have been calculated from computed charged-particle recoils and also derived from measurements using the conventional approximation that all charged particles traverse the chamber. The limitations of the approximation for these neutron spectra are discussed. (author)
Meinardi, Marty
2006-01-01
This project is concerned with the design of English as a Second Language (ESL) courseware for Computer Assisted Language Learning (CALL). It arises out of the Enterprise Ireland funded DITCALL (Digital Interactive Toolkit for Computer Assisted Language learning) project. The focus of the research for this courseware is on using authentic video and audio material that is as natural and true to life as possible and providing adequate, pedagogically efficient and visually pleasing lesson materi...
Koulchitsky, Stanislav; Delairesse, Charlotte; Beeken, Thom; Monteforte, Alexandre; Dethier, Julie; Quertemont, Etienne; Findeisen, Rolf; Bullinger, Eric; Seutin, Vincent
2016-09-01
Psychoactive substances affecting the dopaminergic system induce locomotor activation and, in high doses, stereotypies. Network mechanisms underlying the shift from an active goal-directed behavior to a "seemingly purposeless" stereotypic locomotion remain unclear. In the present study we sought to determine the relationships between the behavioral effects of dopaminergic drugs and their effects on local field potentials (LFPs), which were telemetrically recorded within the ventral tegmental area (VTA) of freely moving rats. We used the D2/D3 agonist quinpirole in a low, autoreceptor-selective (0.1 mg/kg, i.p.) and in a high (0.5 mg/kg, i.p.) dose, and a moderate dose of cocaine (10 mg/kg, i.p.). In the control group, power spectrum analysis revealed a prominent peak of LFP power in the theta frequency range during active exploration. Cocaine alone stimulated locomotion, but had no significant effect on the peak of the LFP power. In contrast, co-administration of low dose quinpirole with cocaine markedly altered the pattern of locomotion, from goal-directed exploratory behavior to recurrent motion resembling locomotor stereotypy. This behavioral effect was accompanied by a shift of the dominant theta power toward a significantly lower (by ∼15%) frequency. High dose quinpirole also provoked an increased locomotor activity with signs of behavioral stereotypies, and also induced a shift of the dominant oscillation frequency toward the lower range. These results demonstrate a correlation between the LFP oscillation frequency within the VTA and a qualitative aspect of locomotor behavior, perhaps due to a variable level of coherence of this region with its input or output areas. Copyright © 2016 Elsevier Ltd. All rights reserved.
Özpiçak, Melek; Saygın, Semra; Polat, Nazmi
2017-01-01
In this study, length-weight relationship (LWR) and length-length relationship (LLR) of bluefish,Pomatomus saltatrix were determined. A total of 125 specimens were sampled from Samsun, themiddle Black Sea in 2014 fishing season. Bluefish specimens were monthly collected fromcommercial fishing boats from October to December 2014. All captured individuals (N=125) weremeasured to the nearest 0.1 cm for total, fork and standard lengths. The weight of each fish (W)was recorded to the nearest 0.01 ...
Directory of Open Access Journals (Sweden)
Melek Özpiçak
2017-10-01
Full Text Available In this study, length-weight relationship (LWR and length-length relationship (LLR of bluefish, Pomatomus saltatrix were determined. A total of 125 specimens were sampled from Samsun, the middle Black Sea in 2014 fishing season. Bluefish specimens were monthly collected from commercial fishing boats from October to December 2014. All captured individuals (N=125 were measured to the nearest 0.1 cm for total, fork and standard lengths. The weight of each fish (W was recorded to the nearest 0.01 g. According to results of analyses, there were no statistically significant differences between sexes in term of length and weight (P˃0.05. The minimum and maximum total, fork and standard lengths of bluefish ranged between 13.5-23.6 cm, 12.50-21.80 cm and 10.60-20.10 cm, respectively. The equation of length-weight relationship were calculated as W=0.008TL3.12 (r2>0.962. Positive allometric growth was observed for bluefish (b>3. Length-length relationship was also highly significant (P<0.001 with coefficient of determination (r2 ranging from 0.916 to 0.988.
Caffeine and length dependence of staircase potentiation in skeletal muscle.
Rassier, D E; Tubman, L A; MacIntosh, B R
1998-01-01
Skeletal muscle sensitivity to Ca2+ is greater at long lengths, and this results in an optimal length for twitch contractions that is longer than optimal length for tetanic contractions. Caffeine abolishes this length dependence of Ca2+ sensitivity. Muscle length (ML) also affects the degree of staircase potentiation. Since staircase potentiation is apparently caused by an increased Ca2+ sensitivity of the myofilaments, we tested the hypothesis that caffeine depresses the length dependence of staircase potentiation. In situ isometric twitch contractions of rat gastrocnemius muscle before and after 10 s of 10-Hz stimulation were analyzed at seven different lengths to evaluate the length dependence of staircase potentiation. In the absence of caffeine, length dependence of Ca2+ sensitivity was observed, and the degree of potentiation after 10-Hz stimulation showed a linear decrease with increased length (DT = 1.47 - 0.05 ML, r2 = 0.95, where DT is developed tension). Length dependence of Ca2+ sensitivity was decreased by caffeine when caffeine was administered in amounts estimated to result in 0.5 and 0.75 mM concentrations. Furthermore, the negative slope of the relationship between staircase potentiation and muscle length was diminished at the lower caffeine dose, and the slope was not different from zero after the higher dose (DT = 1.53 - 0.009 ML, r2 = 0.43). Our study shows that length dependence of Ca2+ sensitivity in intact skeletal muscle is diminished by caffeine. Caffeine also suppressed the length dependence of staircase potentiation, suggesting that the mechanism of this length dependence may be closely related to the mechanism for length dependence of Ca2+ sensitivity.
Critical lengths of error events in convolutional codes
DEFF Research Database (Denmark)
Justesen, Jørn
1994-01-01
If the calculation of the critical length is based on the expurgated exponent, the length becomes nonzero for low error probabilities. This result applies to typical long codes, but it may also be useful for modeling error events in specific codes......If the calculation of the critical length is based on the expurgated exponent, the length becomes nonzero for low error probabilities. This result applies to typical long codes, but it may also be useful for modeling error events in specific codes...
Critical Lengths of Error Events in Convolutional Codes
DEFF Research Database (Denmark)
Justesen, Jørn; Andersen, Jakob Dahl
1998-01-01
If the calculation of the critical length is based on the expurgated exponent, the length becomes nonzero for low error probabilities. This result applies to typical long codes, but it may also be useful for modeling error events in specific codes......If the calculation of the critical length is based on the expurgated exponent, the length becomes nonzero for low error probabilities. This result applies to typical long codes, but it may also be useful for modeling error events in specific codes...
Quantitative trait loci (QTL) mapping for inflorescence length traits in ...
African Journals Online (AJOL)
Lablab purpureus (L.) sweet is an ancient legume species whose immature pods serve as a vegetable in south and south-east Asia. The objective of this study is to identify quantitative trait loci (QTLs) associated with quantitative traits such as inflorescence length, peduncle length from branch to axil, peduncle length from ...
How does harvest size vary with hunting season length?
DEFF Research Database (Denmark)
Sunde, Peter; Asferg, Tommy
2014-01-01
season length (population management/ethical/other). In non-sedentary species, changes in bag size correlated positively with changes in season length (overall response: b = 0.54, 95%CI: 0.14-0.95): reducing the hunting season to 50% of its initial length would on average result in a 31% reduction (95...
Length-Weight Relationship and Condition Factor (K constant) of ...
African Journals Online (AJOL)
Abstract—Length-weight relationships and condition factors of Sparidae along the. Kenyan coast are unknown. This study investigated the length-weight relationship and condition factor of Dentex maroccanus Valenciennes, 1830, a sparid, found in. Malindi, Kenya, from June to August 2008. The length-weight coefficients ...
Integration of length and curvature in haptic perception
Panday, V.; Bergmann Tiest, W.M.; Kappers, A.M.L.
2014-01-01
We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle,
Advantages and risks in increasing cyclone separator length
Hoffmann, AC; de Groot, M; Peng, W; Dries, HWA; Kater, J
The effect of cyclone length on separation efficiency and pressure drop has been investigated experimentally and theoretically by varying the length of the cylindrical segment of a cylinder-on-cone cyclone. Experimental results based on cyclone lengths from 2.65 to 6.15 cyclone diameters showed a
LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF ...
African Journals Online (AJOL)
Data Collection and Analysis. The measurements of length (cm), weight (g) and the condition factor of individual fish sampled were recorded. The relationship between length and weight of the fish was examined by simple linear regression using WINKS software. The variations in the length-weight represented by 'b' were.
Estimation of ocular volume from axial length.
Nagra, Manbir; Gilmartin, Bernard; Logan, Nicola S
2014-12-01
To determine which biometric parameters provide optimum predictive power for ocular volume. Sixty-seven adult subjects were scanned with a Siemens 3-T MRI scanner. Mean spherical error (MSE) (D) was measured with a Shin-Nippon autorefractor and a Zeiss IOLMaster used to measure (mm) axial length (AL), anterior chamber depth (ACD) and corneal radius (CR). Total ocular volume (TOV) was calculated from T2-weighted MRIs (voxel size 1.0 mm(3)) using an automatic voxel counting and shading algorithm. Each MR slice was subsequently edited manually in the axial, sagittal and coronal plane, the latter enabling location of the posterior pole of the crystalline lens and partitioning of TOV into anterior (AV) and posterior volume (PV) regions. Mean values (±SD) for MSE (D), AL (mm), ACD (mm) and CR (mm) were -2.62±3.83, 24.51±1.47, 3.55±0.34 and 7.75±0.28, respectively. Mean values (±SD) for TOV, AV and PV (mm(3)) were 8168.21±1141.86, 1099.40±139.24 and 7068.82±1134.05, respectively. TOV showed significant correlation with MSE, AL, PV (all p<0.001), CR (p=0.043) and ACD (p=0.024). Bar CR, the correlations were shown to be wholly attributable to variation in PV. Multiple linear regression indicated that the combination of AL and CR provided optimum R(2) values of 79.4% for TOV. Clinically useful estimations of ocular volume can be obtained from measurement of AL and CR. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
Memory for tonal pitches: a music-length effect hypothesis.
Akiva-Kabiri, Lilach; Vecchi, Tomaso; Granot, Roni; Basso, Demis; Schön, Daniele
2009-07-01
One of the most studied effects of verbal working memory (WM) is the influence of the length of the words that compose the list to be remembered. This work aims to investigate the nature of musical WM by replicating the word length effect in the musical domain. Length and rate of presentation were manipulated in a recognition task of tone sequences. Results showed significant effects for both factors (length and presentation rate) as well as their interaction, suggesting the existence of different strategies (e.g., chunking and rehearsal) for the immediate memory of musical information, depending upon the length of the sequences.
Kaspers, O. P.; Sterenborg, H. J. C. M.; Amelink, A.
2008-01-01
We have characterized the path length for the differential path-length spectroscopy (DPS) fiber optic geometry for a wide range of optical properties and for fiber diameters ranging from 200 mu m to 1000 mu m. Phantom measurements show that the path length is nearly constant for scattering
Correlation length estimation in a polycrystalline material model
International Nuclear Information System (INIS)
Simonovski, I.; Cizelj, L.
2005-01-01
This paper deals with the correlation length estimated from a mesoscopic model of a polycrystalline material. The correlation length can be used in some macroscopic material models as a material parameter that describes the internal length. It can be estimated directly from the strain and stress fields calculated from a finite-element model, which explicitly accounts for the selected mesoscopic features such as the random orientation, shape and size of the grains. A crystal plasticity material model was applied in the finite-element analysis. Different correlation lengths were obtained depending on the used set of crystallographic orientations. We determined that the different sets of crystallographic orientations affect the general level of the correlation length, however, as the external load is increased the behaviour of correlation length is similar in all the analyzed cases. The correlation lengths also changed with the macroscopic load. If the load is below the yield strength the correlation lengths are constant, and are slightly higher than the average grain size. The correlation length can therefore be considered as an indicator of first plastic deformations in the material. Increasing the load above the yield strength creates shear bands that temporarily increase the values of the correlation lengths calculated from the strain fields. With a further load increase the correlation lengths decrease slightly but stay above the average grain size. (author)
Automated path length and M56 measurements at Jefferson Lab
International Nuclear Information System (INIS)
Hardy, D.; Tang, J.; Legg, R.
1997-01-01
Accurate measurement of path length and path length changes versus momentum (M 56 ) are critical for maintaining minimum beam energy spread in the CEBAF (Continuous Electron Beam Accelerator Facility) accelerator at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The relative path length for each circuit of the beam (1256m) must be equal within 1.5 degrees of 1497 MHz RF phase. A relative path length measurement is made by measuring the relative phases of RF signals from a cavity that is separately excited for each pass of a 4.2 μs pulsed beam. This method distinguishes the path length to less than 0.5 path length error. The development of a VME based automated measurement system for path length and M 56 has contributed to faster machine setup time and has the potential for use as a feedback parameter for automated control
Integration of length and curvature in haptic perception.
Panday, Virjanand; Tiest, Wouter M Bergmann; Kappers, Astrid M L
2014-01-24
We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle, or anti-correlated. We found that when both length and curvature are present, performance is significantly better than when only one of the two cues is available. Therefore, we conclude that there is integration of length and curvature. Moreover, if the two cues are correlated in a circular cross-section instead of in an anti-correlated way, performance is better than predicted by a combination of two independent cues. We conclude that integration of curvature and length is highly efficient when the cues in the object are combined as in a circle, which is the most common combination of curvature and length in daily life.
Campbell, Paul T; Kruse, Kevin R; Kroll, Christopher R; Patterson, Janet Y; Esposito, Michele J
2015-09-01
Coronary stent deployment outcomes can be negatively impacted by inaccurate lesion measurement and inappropriate stent length selection (SLS). We compared visual estimate of these parameters to those provided by the CorPath 200® Robotic PCI System. Sixty consecutive patients who underwent coronary stent placement utilizing the CorPath System were evaluated. The treating physician assessed orthogonal images and provided visual estimates of lesion length and SLS. The robotic system was then used for the same measures. SLS was considered to be accurate when visual estimate and robotic measures were in agreement. Visual estimate SLSs were considered to be "short" or "long" if they were below or above the robotic-selected stents, respectively. Only 35% (21/60) of visually estimated lesions resulted in accurate SLS, whereas 33% (20/60) and 32% (19/60) of the visually estimated SLSs were long and short, respectively. In 5 cases (8.3%), 1 less stent was placed based on the robotic lesion measurement being shorter than the visual estimate. Visual estimate assessment of lesion length and SLS is highly variable with 65% of the cases being inaccurately measured when compared to objective measures obtained from the robotic system. The 32% of the cases where lesions were visually estimated to be short represents cases that often require the use of extra stents after the full lesion is not covered by 1 stent [longitudinal geographic miss (LGM)]. Further, these data showed that the use of the robotic system prevented the use of extra stents in 8.3% of the cases. Measurement of lesions with robotic PCI may reduce measurement errors, need for extra stents, and LGM. Copyright © 2015 Elsevier Inc. All rights reserved.
Maternal telomere length inheritance in the king penguin.
Reichert, S; Rojas, E R; Zahn, S; Robin, J-P; Criscuolo, F; Massemin, S
2015-01-01
Telomeres are emerging as a biomarker for ageing and survival, and are likely important in shaping life-history trade-offs. In particular, telomere length with which one starts in life has been linked to lifelong survival, suggesting that early telomere dynamics are somehow related to life-history trajectories. This result highlights the importance of determining the extent to which telomere length is inherited, as a crucial factor determining early life telomere length. Given the scarcity of species for which telomere length inheritance has been studied, it is pressing to assess the generality of telomere length inheritance patterns. Further, information on how this pattern changes over the course of growth in individuals living under natural conditions should provide some insight on the extent to which environmental constraints also shape telomere dynamics. To fill this gap partly, we followed telomere inheritance in a population of king penguins (Aptenodytes patagonicus). We tested for paternal and maternal influence on chick initial telomere length (10 days old after hatching), and how these relationships changed with chick age (at 70, 200 and 300 days old). Based on a correlative approach, offspring telomere length was positively associated with maternal telomere length early in life (at 10 days old). However, this relationship was not significant at older ages. These data suggest that telomere length in birds is maternally inherited. Nonetheless, the influence of environmental conditions during growth remained an important factor shaping telomere length, as the maternal link disappeared with chicks' age.
Correcting length-frequency distributions for imperfect detection
Breton, André R.; Hawkins, John A.; Winkelman, Dana L.
2013-01-01
Sampling gear selects for specific sizes of fish, which may bias length-frequency distributions that are commonly used to assess population size structure, recruitment patterns, growth, and survival. To properly correct for sampling biases caused by gear and other sources, length-frequency distributions need to be corrected for imperfect detection. We describe a method for adjusting length-frequency distributions when capture and recapture probabilities are a function of fish length, temporal variation, and capture history. The method is applied to a study involving the removal of Smallmouth Bass Micropterus dolomieu by boat electrofishing from a 38.6-km reach on the Yampa River, Colorado. Smallmouth Bass longer than 100 mm were marked and released alive from 2005 to 2010 on one or more electrofishing passes and removed on all other passes from the population. Using the Huggins mark–recapture model, we detected a significant effect of fish total length, previous capture history (behavior), year, pass, year×behavior, and year×pass on capture and recapture probabilities. We demonstrate how to partition the Huggins estimate of abundance into length frequencies to correct for these effects. Uncorrected length frequencies of fish removed from Little Yampa Canyon were negatively biased in every year by as much as 88% relative to mark–recapture estimates for the smallest length-class in our analysis (100–110 mm). Bias declined but remained high even for adult length-classes (≥200 mm). The pattern of bias across length-classes was variable across years. The percentage of unadjusted counts that were below the lower 95% confidence interval from our adjusted length-frequency estimates were 95, 89, 84, 78, 81, and 92% from 2005 to 2010, respectively. Length-frequency distributions are widely used in fisheries science and management. Our simple method for correcting length-frequency estimates for imperfect detection could be widely applied when mark–recapture data
Thermal significance of fission-track length distributions
International Nuclear Information System (INIS)
Crowley, K.D.
1985-01-01
The semi-analytical solution of an equation describing the production and shortening of fission tracks in apatite suggests that certain thermal histories have unique length-distribution 'signatures'. Isothermal-heating histories should be characterized by flattened, length-shortened distributions; step-heating histories should be characterized by bimodal track length distributions; and linear-cooling histories should be characterized by negatively skewed, length-shortened distributions. The model formulated here to investigate track length distributions can be used to constrain the thermal histories of natural samples for which unbiased track length data are available - provided that the geologic history of the system of interest can be used to partially constrain one of the unknowns in the model equations, time or temperature. (author)
Sperm length evolution in the fungus-growing ants
DEFF Research Database (Denmark)
Baer, B.; Dijkstra, M. B.; Mueller, U. G.
2009-01-01
-growing ants, representing 9 of the 12 recognized genera, and mapped these onto the ant phylogeny. We show that average sperm length across species is highly variable and decreases with mature colony size in basal genera with singly mated queens, suggesting that sperm production or storage constraints affect...... the evolution of sperm length. Sperm length does not decrease further in multiply mating leaf-cutting ants, despite substantial further increases in colony size. In a combined analysis, sexual dimorphism explained 63.1% of the variance in sperm length between species. As colony size was not a significant...... predictor in this analysis, we conclude that sperm production trade-offs in males have been the major selective force affecting sperm length across the fungus-growing ants, rather than storage constraints in females. The relationship between sperm length and sexual dimorphism remained robust...
Bond-Length Distortions in Strained Semiconductor Alloys
International Nuclear Information System (INIS)
Woicik, J.C.; Pellegrino, J.G.; Steiner, B.; Miyano, K.E.; Bompadre, S.G.; Sorensen, L.B.; Lee, T.; Khalid, S.
1997-01-01
Extended x-ray absorption fine structure measurements performed at In-K edge have resolved the outstanding issue of bond-length strain in semiconductor-alloy heterostructures. We determine the In-As bond length to be 2.581±0.004 Angstrom in a buried, 213 Angstrom thick Ga 0.78 In 0.22 As layer grown coherently on GaAs(001). This bond length corresponds to a strain-induced contraction of 0.015±0.004 Angstrom relative to the In-As bond length in bulk Ga 1-x In x As of the same composition; it is consistent with a simple model which assumes a uniform bond-length distortion in the epilayer despite the inequivalent In-As and Ga-As bond lengths. copyright 1997 The American Physical Society
Upper bound for the length of commutative algebras
International Nuclear Information System (INIS)
Markova, Ol'ga V
2009-01-01
By the length of a finite system of generators for a finite-dimensional associative algebra over an arbitrary field one means the least positive integer k such that the words of length not exceeding k span this algebra (as a vector space). The maximum length for the systems of generators of an algebra is referred to as the length of the algebra. In the present paper, an upper bound for the length of a commutative algebra in terms of a function of two invariants of the algebra, the dimension and the maximal degree of the minimal polynomial for the elements of the algebra, is obtained. As a corollary, a formula for the length of the algebra of diagonal matrices over an arbitrary field is obtained. Bibliography: 8 titles.
Relation between Tolman length and isothermal compressibility for simple liquids
International Nuclear Information System (INIS)
Wang Xiao-Song; Zhu Ru-Zeng
2013-01-01
The Tolman length δ 0 of a liquid with a plane surface has attracted increasing theoretical attention in recent years, but the expression of Tolman length in terms of observable quantities is still not very clear. In 2001, Bartell gave a simple expression of Tolman length δ 0 in terms of isothermal compressibility. However, this expression predicts that Tolman length is always negative, which is contrary to the results of molecular dynamics simulations (MDS) for simple liquids. In this paper, this contradiction is analyzed and the reason for the discrepancy in the sign is found. In addition, we introduce a new expression of Tolman length in terms of isothermal compressibility for simple fluids not near the critical points under some weak restrictions. The Tolman length of simple liquids calculated by using this formula is consistent with that obtained using MDS regarding the sign
Finite fission chain length and symmetry around prompt-criticality
International Nuclear Information System (INIS)
Xie Qilin; Yin Yanpeng; Gao Hui; Huang Po; Fang Xiaoqiang
2012-01-01
Probability distribution of finite fission chain length was derived by assuming that all neutrons behave identically. Finite fission chain length was also calculated using a zero-dimension Monte-Carlo method based on point kinetics. Then symmetry of finite fission chain length probability distribution around prompt-criticality was deduced, which helps understanding the emission rate of delayed neutrons and initiation of fission chain in super-prompt-critical system. (authors)
Cervical length measurement: comparison of transabdominal and transvaginal approach
DEFF Research Database (Denmark)
Westerway, Sue C; Pedersen, Lars Henning; Hyett, Jon
2015-01-01
to external cervical os. Bland- Altman plots and Wilcoxon signed rank test were used to evaluate differences between TA and TV measurements. Results: The validity of the TA method depended on cervical length. Although the TA method underestimated cervical length by 2.0 mm on average (P ... plots showed an inverse trend with shorter cervixes. In women with a cervix test to detect cervical length
Potts ferromagnet correlation length in hypercubic lattices: Renormalization - group approach
International Nuclear Information System (INIS)
Curado, E.M.F.; Hauser, P.R.
1984-01-01
Through a real space renormalization group approach, the q-state Potts ferromagnet correlation length on hierarchical lattices is calculated. These hierarchical lattices are build in order to simulate hypercubic lattices. The high-and-low temperature correlation length asymptotic behaviours tend (in the Ising case) to the Bravais lattice correlation length ones when the size of the hierarchical lattice cells tends to infinity. It is conjectured that the asymptotic behaviours several values of q and d (dimensionality) so obtained are correct. Numerical results are obtained for the full temperature range of the correlation length. (Author) [pt
Bunch length measurements in the SLC damping ring
International Nuclear Information System (INIS)
Decker, F.J.; Limberg, T.; Minty, M.; Ross, M.
1993-05-01
The synchrotron light of the SLC damping ring was used to measure the bunch length with a streak camera at different times in the damping cycle. There are bunch length oscillations after injection, different equilibrium length during the cycle due to rf manipulations to avoid microwave instability oscillations, and just before extraction there is a longitudinal phase space rotation (bunch muncher) to shorten the bunch length. Measurements under these different conditions are presented and compared with BPM pulse height signals. Calibration and adjustment issues and the connection of the streak camera to the SLC control system are also discussed
Universal and idiosyncratic characteristic lengths in bacterial genomes
Junier, Ivan; Frémont, Paul; Rivoire, Olivier
2018-05-01
In condensed matter physics, simplified descriptions are obtained by coarse-graining the features of a system at a certain characteristic length, defined as the typical length beyond which some properties are no longer correlated. From a physics standpoint, in vitro DNA has thus a characteristic length of 300 base pairs (bp), the Kuhn length of the molecule beyond which correlations in its orientations are typically lost. From a biology standpoint, in vivo DNA has a characteristic length of 1000 bp, the typical length of genes. Since bacteria live in very different physico-chemical conditions and since their genomes lack translational invariance, whether larger, universal characteristic lengths exist is a non-trivial question. Here, we examine this problem by leveraging the large number of fully sequenced genomes available in public databases. By analyzing GC content correlations and the evolutionary conservation of gene contexts (synteny) in hundreds of bacterial chromosomes, we conclude that a fundamental characteristic length around 10–20 kb can be defined. This characteristic length reflects elementary structures involved in the coordination of gene expression, which are present all along the genome of nearly all bacteria. Technically, reaching this conclusion required us to implement methods that are insensitive to the presence of large idiosyncratic genomic features, which may co-exist along these fundamental universal structures.
The relationship of protein conservation and sequence length
Directory of Open Access Journals (Sweden)
Panchenko Anna R
2002-11-01
Full Text Available Abstract Background In general, the length of a protein sequence is determined by its function and the wide variance in the lengths of an organism's proteins reflects the diversity of specific functional roles for these proteins. However, additional evolutionary forces that affect the length of a protein may be revealed by studying the length distributions of proteins evolving under weaker functional constraints. Results We performed sequence comparisons to distinguish highly conserved and poorly conserved proteins from the bacterium Escherichia coli, the archaeon Archaeoglobus fulgidus, and the eukaryotes Saccharomyces cerevisiae, Drosophila melanogaster, and Homo sapiens. For all organisms studied, the conserved and nonconserved proteins have strikingly different length distributions. The conserved proteins are, on average, longer than the poorly conserved ones, and the length distributions for the poorly conserved proteins have a relatively narrow peak, in contrast to the conserved proteins whose lengths spread over a wider range of values. For the two prokaryotes studied, the poorly conserved proteins approximate the minimal length distribution expected for a diverse range of structural folds. Conclusions There is a relationship between protein conservation and sequence length. For all the organisms studied, there seems to be a significant evolutionary trend favoring shorter proteins in the absence of other, more specific functional constraints.
Al-jebory, Taymaa A.; Das, Simon K.; Usup, Gires; Bakar, Y.; Al-saadi, Ali H.
2018-04-01
In this study, length-weight and length-length relationships of common carp (Cyprinus carpio L.) in the middle and southern Iraq provinces were determined. Fish specimens were procured from seven provinces from July to December, 2015. A negative and positive allometric growth pattern was obtained, where the total length (TL) ranged from 25.60 cm to 33.53 cm, and body weight (BW) ranged from 700 g to 1423 g. Meanwhile, the lowest of 1.03 and highest of 3.54 in "b" value was recorded in group F and group C, respectively. Therefore, Fulton condition factor (K) range from 2.57 to 4.94. While, relative condition factor (Kn) was in the ranged of 0.95 to 1.01. A linear relationship between total length (TL) and standard length (SL) among the provinces for fish groups was obtained. The variances in "b" value ranged from 0.10 to 0.93 with correlation coefficient (r2) of 0.02 to 0.97. This research could be used as a guide to study the ecology and biology of common Carp (Cyprinus carpio L.) in the middle and southern Iraq provinces.
Compliant walking appears metabolically advantageous at extreme step lengths.
Kim, Jaehoon; Bertram, John E A
2018-05-19
Humans alter gait in response to unusual gait circumstances to accomplish the task of walking. For instance, subjects spontaneously increase leg compliance at a step length threshold as step length increases. Here we test the hypothesis that this transition occurs based on the level of energy expenditure, where compliant walking becomes less energetically demanding at long step lengths. To map and compare the metabolic cost of normal and compliant walking as step length increases. 10 healthy individuals walked on a treadmill using progressively increasing step lengths (100%, 120%, 140% and 160% of preferred step length), in both normal and compliant leg walking as energy expenditure was recorded via indirect calorimetry. Leg compliance was controlled by lowering the center-of-mass trajectory during stance, forcing the leg to flex and extend as the body moved over the foot contact. For normal step lengths, compliant leg walking was more costly than normal walking gait, but compliant leg walking energetic cost did not increase as rapidly for longer step lengths. This led to an intersection between normal and compliant walking cost curves at 114% relative step length (regression analysis; r 2 = 0.92 for normal walking; r 2 = 0.65 for compliant walking). Compliant leg walking is less energetically demanding at longer step lengths where a spontaneous shift to compliant walking has been observed, suggesting the human motor control system is sensitive to energetic requirements and will employ alternate movement patterns if advantageous strategies are available. The transition could be attributed to the interplay between (i) leg work controlling body travel during single stance and (ii) leg work to control energy loss in the step-to-step transition. Compliant leg walking requires more stance leg work at normal step lengths, but involves less energy loss at the step-to-step transition for very long steps. Copyright © 2018 Elsevier B.V. All rights reserved.
Diagnostic value of newborn foot length to predict gestational age
Directory of Open Access Journals (Sweden)
Mutia Farah Fawziah
2017-08-01
Full Text Available Background Identification of gestational age, especially within 48 hours of birth, is crucial for newborns, as the earlier preterm status is detected, the earlier the child can receive optimal management. Newborn foot length is an anthropometric measurement which is easy to perform, inexpensive, and potentially efficient for predicting gestational age. Objective To analyze the diagnostic value of newborn foot length in predicting gestational age. Methods This diagnostic study was performed between October 2016 and February 2017 in the High Care Unit of Neonates at Dr. Moewardi General Hospital, Surakarta. A total of 152 newborns were consecutively selected and underwent right foot length measurements before 96 hours of age. The correlation between newborn foot length to classify as full term and gestational age was analyzed with Spearman’s correlation test because of non-normal data distribution. The cut-off point of newborn foot length was calculated by receiver operating characteristic (ROC curve and diagnostic values of newborn foot length were analyzed by 2 x 2 table with SPSS 21.0 software. Results There were no significant differences between male and female newborns in terms of gestational age, birth weight, choronological age, and newborn foot length (P>0.05. Newborn foot length and gestational age had a significant correlation (r=0.53; P=0.000. The optimal cut-off newborn foot length to predict full term status was 7.1 cm. Newborn foot length below 7.1 cm had sensitivity 75%, specificity 98%, positive predictive value 94.3%, negative predictive value 90.6%, positive likelihood ratio 40.5, negative likelihood ratio 0.25, and post-test probability 94.29%, to predict preterm status in newborns. Conclusion Newborn foot length can be used to predict gestational age, especially for the purpose of differentiating between preterm and full term newborns.
Crandall, David Lynn
2011-08-16
Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.
Spatial correlation length of normalized cone data in sand
DEFF Research Database (Denmark)
Firouzianbandpey, Sarah; Griffiths, D. V.; Ibsen, Lars Bo
2014-01-01
The main topic of this study is to assess the anisotropic spatial correlation lengths of a sand layer deposit based on cone penetration testing with pore pressure measurement (CPTu) data. Spatial correlation length can be an important factor in reliability analysis of geotechnical systems, yet it...
The Influence of Presentation Method on Auditory Length Perception
DEFF Research Database (Denmark)
Kirkwood, Brent Christopher
Humans are capable of hearing the lengths of wooden rods dropped onto hard floors. In an attempt to understand the influence of the stimulus presentation method for testing this kind of everyday listening task, listener performance was compared for three presentation methods in an auditory length...
The influence of presentation method on auditory length perception
DEFF Research Database (Denmark)
Kirkwood, Brent Christopher
2005-01-01
Humans are capable of hearing the lengths of wooden rods dropped onto hard floors. In an attempt to understand the influence of the stimulus presentation method for testing this kind of everyday listening task, listener performance was compared for three presentation methods in an auditory length...
The impact of cultural distance on bilateral arm's length exports
Slangen, A.H.L.; Beugelsdijk, S.; Hennart, J.-F.
2011-01-01
Prior studies have argued and regularly found that cultural distance is negatively related to bilateral export flows, which are the sum of arm’s length and intra-firm exports. However, these macro-level studies overlook the firm-level insights that arm’s length exports are a substitute for arm’s
Ultrasonographic assessment of renal length in 310 Turkish children ...
African Journals Online (AJOL)
Scanning was performed with a 3.5 MHz ultrasound probe in the supine position. The ultrasonographic appearance of the kidneys we measured was normal. The maximum length of each kidney was measured. The renal length was correlated with somatic parameters including age, body height and weight. Regression ...
Design Matters: The Impact of CAPI on Interview Length
Watson, Nicole; Wilkins, Roger
2015-01-01
Computer-assisted personal interviewing (CAPI) offers many attractive benefits over paper-and-pencil interviewing. There is, however, mixed evidence on the impact of CAPI on interview "length," an important survey outcome in the context of length limits imposed by survey budgets and concerns over respondent burden. In this article,…
length-weight relationship of hepsetus odoe in lapai - agaie ...
African Journals Online (AJOL)
Ibrahim Usman
biometric relationship so that data collected from the field can be transform into appropriate indices (Ecoutin et al., 2005). Length and weight are two useful parameters used especially in fisheries assessment. This relationship known as length-weight relationship (LWR), is commonly used in the analysis of fisheries data.
Word Length Effects in Long-Term Memory
Tehan, Gerald; Tolan, Georgina Anne
2007-01-01
The word length effect has been a central feature of theorising about immediate memory. The notion that short-term memory traces rapidly decay unless refreshed by rehearsal is based primarily upon the finding that serial recall for short words is better than that for long words. The decay account of the word length effect has come under pressure…
Assessing impact of climate change on season length in Karnataka
Indian Academy of Sciences (India)
Changes in seasons and season length are an indicator, as well as an effect, of climate change. Seasonal change profoundly affects the balance of life in ecosystems and impacts essential human activities such as agriculture and irrigation. This study investigates the uncertainty of season length in Karnataka state, India, ...
A Small Crack Length Evaluation Technique by Electronic Scanning
International Nuclear Information System (INIS)
Cho, Yong Sang; Kim, Jae Hoon
2009-01-01
The results of crack evaluation by conventional UT(Ultrasonic Test)is highly depend on the inspector's experience or knowledge of ultrasound. Phased array UT system and its application methods for small crack length evaluation will be a good alternative method which overcome present UT weakness. This study was aimed at checking the accuracy of crack length evaluation method by electronic scanning and discuss about characteristics of electronic scanning for crack length evaluation. Especially ultrasonic phased array with electronic scan technique was used in carrying out both sizing and detect ability of crack as its length changes. The response of ultrasonic phased array was analyzed to obtain the special method of determining crack length without moving the transducer and detectability of crack minimal length and depth from the material. A method of crack length determining by electronic scanning for the small crack is very real method which has it's accuracy and verify the effectiveness of method compared to a conventional crack length determination
EFFECT OF EXERCISE ON CYCLE LENGTH IN ATRIAL-FLUTTER
VANDENBERG, MP; CRIJNS, HJGM; SZABO, BM; BROUWER, J; LIE, KI
Objective-To examine the effect of exercise on cycle length in atrial flutter. Patients-15 patients with chronic atrial flutter. Seven patients were taking digoxin and six verapamil; two were not taking medication. Methods-All patients underwent bicycle ergometry. Flutter cycle length was measured
Accuracy of working length determination with root ZX apex locator ...
African Journals Online (AJOL)
The purpose of this study was to clinically compare working length (WL) determination with root ZX apex locator and radiography, and then compare them with direct visualization method ex vivo. A total of 75 maxillary central and lateral incisors were selected. Working length determination was carried out using radiographic ...
Length-weight relationships, condition factors and relative weight of ...
African Journals Online (AJOL)
The aim of this study was to record the length-weight relationship parameters and condition factors for some commercially important fish of Bushehr coastal waters of Persian Gulf. The length-weight relationships were calculated for five species caught during fishing surveys using different types of fishing gears (trawls, pots ...
Optimization of fracture length in gas/condensate reservoirs
Energy Technology Data Exchange (ETDEWEB)
Mohan, J.; Sharma, M.M.; Pope, G.A. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Texas Univ., Austin, TX (United States)
2006-07-01
A common practice that improves the productivity of gas-condensate reservoirs is hydraulic fracturing. Two important variables that determine the effectiveness of hydraulic fractures are fracture length and fracture conductivity. Although there are no simple guidelines for the optimization of fracture length and the factors that affect it, it is preferable to have an optimum fracture length for a given proppant volume in order to maximize productivity. An optimization study was presented in which fracture length was estimated at wells where productivity was maximized. An analytical expression that takes into account non-Darcy flow and condensate banking was derived. This paper also reviewed the hydraulic fracturing process and discussed previous simulation studies that investigated the effects of well spacing and fracture length on well productivity in low permeability gas reservoirs. The compositional simulation study and results and discussion were also presented. The analytical expression for optimum fracture length, analytical expression with condensate dropout, and equations for the optimum fracture length with non-Darcy flow in the fracture were included in an appendix. The Computer Modeling Group's GEM simulator, an equation-of-state compositional simulator, was used in this study. It was concluded that for cases with non-Darcy flow, the optimum fracture lengths are lower than those obtained with Darcy flow. 18 refs., 5 tabs., 22 figs., 1 appendix.
Working Length Determination of Root Canal of Young Permanent ...
African Journals Online (AJOL)
Working Length Determination of Root Canal of Young Permanent Tooth: An In Vitro Study. A Diwanji, AS Rathore, R Arora, V Dhar, A Madhusudan, J Doshi. Abstract. Background: Determination of correct working length is one of the keys to success in endodontic therapy. Aim: The aim of this study was to evaluate the ...
Biophysics of filament length regulation by molecular motors
International Nuclear Information System (INIS)
Kuan, Hui-Shun; Betterton, M D
2013-01-01
Regulating physical size is an essential problem that biological organisms must solve from the subcellular to the organismal scales, but it is not well understood what physical principles and mechanisms organisms use to sense and regulate their size. Any biophysical size-regulation scheme operates in a noisy environment and must be robust to other cellular dynamics and fluctuations. This work develops theory of filament length regulation inspired by recent experiments on kinesin-8 motor proteins, which move with directional bias on microtubule filaments and alter microtubule dynamics. Purified kinesin-8 motors can depolymerize chemically-stabilized microtubules. In the length-dependent depolymerization model, the rate of depolymerization tends to increase with filament length, because long filaments accumulate more motors at their tips and therefore shorten more quickly. When balanced with a constant filament growth rate, this mechanism can lead to a fixed polymer length. However, the mechanism by which kinesin-8 motors affect the length of dynamic microtubules in cells is less clear. We study the more biologically realistic problem of microtubule dynamic instability modulated by a motor-dependent increase in the filament catastrophe frequency. This leads to a significant decrease in the mean filament length and a narrowing of the filament length distribution. The results improve our understanding of the biophysics of length regulation in cells. (paper)
Length-weight relationship and condition factor of clarias gariepinus ...
African Journals Online (AJOL)
Length-Weight relationship and condition factor of Clarias gariepinus and Tilapia Zillii were studiedin lake Alau and Monguno hatchery, both in Borno State of Nigeria, for a period of two weeks. A total of 98 C. gariepinus and 140. T. zillii were measured. The length-weight regression coefficient (b) for both fishes in lake Alau ...
Reason for termination of breastfeeding and the length of breastfeeding
DEFF Research Database (Denmark)
Jakobsen, M S; Sodemann, Morten; Mølbak, Kare
1996-01-01
In third world countries the length of breastfeeding often has a major influence on child mortality, morbidity and nutritional status. When evaluating the impact of length of breastfeeding the reason why a mother terminates breastfeeding is usually not taken into consideration....
Young Children's Understandings of Length Measurement: Evaluating a Learning Trajectory
Szilagyi, Janka; Clements, Douglas H.; Sarama, Julie
2013-01-01
This study investigated the development of length measurement ideas in students from prekindergarten through 2nd grade. The main purpose was to evaluate and elaborate the developmental progression, or levels of thinking, of a hypothesized learning trajectory for length measurement to ensure that the sequence of levels of thinking is consistent…
Prediction of the mixing length in effluent transport in rivers
International Nuclear Information System (INIS)
Szpilowski, S.
1983-01-01
Studies have been performed on estimating the transverse mixing length of effluents discharged into rivers. The proposed method is based on measured values of the dispersion coefficient. Field investigations were carried out in the River Vistula in the Warsaw area using radiotracer methods. The procedure can be used for predicting the mixing length in designing sewage systems. (author)
Climate reconstructions derived from global glacier length records
Klok, E.J.; Oerlemans, J.
2004-01-01
As glacier length fluctuations provide useful information about past climate, we derived historic fluctuations in the equilibrium-line altitude (ELA) on the basis of 19 glacier length records from different parts of the world. We used a model that takes into account the geometry of the glacier,
Time step length versus efficiency of Monte Carlo burnup calculations
International Nuclear Information System (INIS)
Dufek, Jan; Valtavirta, Ville
2014-01-01
Highlights: • Time step length largely affects efficiency of MC burnup calculations. • Efficiency of MC burnup calculations improves with decreasing time step length. • Results were obtained from SIE-based Monte Carlo burnup calculations. - Abstract: We demonstrate that efficiency of Monte Carlo burnup calculations can be largely affected by the selected time step length. This study employs the stochastic implicit Euler based coupling scheme for Monte Carlo burnup calculations that performs a number of inner iteration steps within each time step. In a series of calculations, we vary the time step length and the number of inner iteration steps; the results suggest that Monte Carlo burnup calculations get more efficient as the time step length is reduced. More time steps must be simulated as they get shorter; however, this is more than compensated by the decrease in computing cost per time step needed for achieving a certain accuracy
Impact of Cyclic Prefix length on OFDM system Capacity
DEFF Research Database (Denmark)
Rom, Christian; Sørensen, Troels Bundgaard; Mogensen, Preben Elgaard
2005-01-01
This paper is a study on the impact of the Cyclic Prefix (CP) length on the downlink Capacity in a base-band synchronized SISO-OFDM context. To measure this impact, the capacity, measured in bits per second per hertz, is chosen as quality parameter. The study shows how the lengthening of the CP......) the useful OFDM symbol duration, 2) the Signal to Noise Ratio (SNR) at the receiver and 3) the channel Power Delay Profile (PDP). Depending on the values of these parameters different optimum CP lengths are obtained. For a system using only one value of CP length we suggest an optimum value to be 4us...... for an OFDM symbol length of 40us and 6us for an OFDM symbol length of 80us....
Relative gut lengths of coral reef butterflyfishes (Pisces: Chaetodontidae)
Berumen, Michael L.; Pratchett, Morgan S.; Goodman, Brett Alexander
2011-01-01
Variation in gut length of closely related animals is known to generally be a good predictor of dietary habits. We examined gut length in 28 species of butterflyfishes (Chaetodontidae), which encompass a wide range of dietary types (planktivores, omnivores, and corallivores). We found general dietary patterns to be a good predictor of relative gut length, although we found high variation among groups and covariance with body size. The longest gut lengths are found in species that exclusively feed on the living tissue of corals, while the shortest gut length is found in a planktivorous species. Although we tried to control for phylogeny, corallivory has arisen multiple times in this family, confounding our analyses. The butterflyfishes, a speciose family with a wide range of dietary habits, may nonetheless provide an ideal system for future work studying gut physiology associated with specialization and foraging behaviors. © 2011 Springer-Verlag.
Foot length is a functional parameter for assessment of height.
Krishan, Kewal; Kanchan, Tanuj
2013-03-01
Stature estimation is considered as an important parameter in the examination of unknown human remains and during the analysis of evidence in crime scene investigations. During mass disasters isolated foot can be found enclosed in the shoes while footprints may be recovered at the crime scenes. Foot length and footprint length can provide valuable estimates of stature. The present communication makes a few pertinent observations on a recently published article in 'The Foot' entitled 'Foot length-a functional parameter for assessment of height, The Foot 2012, 22(1):31-34' and presents an insight into the literature available on the subject which is likely to be of value to future researchers in the field of Forensic Podiatry. The foot length and the footprint length of individuals differ from each other and hence, the research observations made in a study on foot prints cannot be applied to foot dimensions. Copyright © 2012 Elsevier Ltd. All rights reserved.
Relative gut lengths of coral reef butterflyfishes (Pisces: Chaetodontidae)
Berumen, Michael L.
2011-06-17
Variation in gut length of closely related animals is known to generally be a good predictor of dietary habits. We examined gut length in 28 species of butterflyfishes (Chaetodontidae), which encompass a wide range of dietary types (planktivores, omnivores, and corallivores). We found general dietary patterns to be a good predictor of relative gut length, although we found high variation among groups and covariance with body size. The longest gut lengths are found in species that exclusively feed on the living tissue of corals, while the shortest gut length is found in a planktivorous species. Although we tried to control for phylogeny, corallivory has arisen multiple times in this family, confounding our analyses. The butterflyfishes, a speciose family with a wide range of dietary habits, may nonetheless provide an ideal system for future work studying gut physiology associated with specialization and foraging behaviors. © 2011 Springer-Verlag.
Length of urethra in the Indian adult male population
Directory of Open Access Journals (Sweden)
Venkatesh Krishnamoorthy
2012-01-01
Full Text Available Objective: The urethral length has not been measured in the Indian population. Even the international literature in this arena is very sparse. This paper is an attempt to develop a simple anatomical database for urethral length. Materials and Methods: Between January 2010 and April 2011, the urethral lengths of 422 adult male patients who required catheterization as part of regular treatment at our hospital, were recorded after obtaining consent from the patients and from the scientific and ethics review boards of the institution. Patients with history of prostatic or urethral abnormalities were excluded. The balloon of a sterile Foley′s catheter was inflated using 10 cc of saline. The length from the junction of the balloon to the ′Y′ junction of the Foley was measured. The catheter was then passed into the bladder and re-inflated to same volume. The penis was gently straightened and the length of the catheter outside the penis was measured till the premarked point at the ′Y′ junction. Subtracting this from the original length gave the length of the urethra. Results: The mean length of the urethra was 17.55 + 1.42 cm with a range between 14 and 22.5 cm. Conclusions: Literature in which the length of the normal adult male urethra is recorded for a significant sample size is very scarce. Our data adds to basic anatomic information of the male urethra specific to the Indian population. Statistical Methods: Descriptive statistical analysis was performed. The non-linear regression analysis was employed to find the normative values of urethral length according to age class.
Verhoeven, J.W.; Aken, J. van; Weerdt, G.P. van der
Intraoral radiograms can be made according to the long tube paralleling technique utilizing aiming devices. An important factor in the design of these instruments is the length of the teeth to be radiographed. Reliable data regarding the length of the teeth in the different regions of the mouth are
James S. Han; Theodore. Mianowski; Yi-yu. Lin
1999-01-01
The efficacy of fiber length measurement techniques such as digitizing, the Kajaani procedure, and NIH Image are compared in order to determine the optimal tool. Kenaf bast fibers, aspen, and red pine fibers were collected from different anatomical parts, and the fiber lengths were compared using various analytical tools. A statistical analysis on the validity of the...
Cheung, S.K.; van den Berg, Hans Leo; Boucherie, Richardus J.
2005-01-01
We obtain a decomposition result for the steady state queue length distribution in egalitarian processor-sharing (PS) models. In particular, for an egalitarian PS queue with $K$ customer classes, we show that the marginal queue length distribution for class $k$ factorizes over the number of other
Marinus, E.; de Jong, P.F.
2010-01-01
The marked word-length effect in dyslexic children suggests the use of a letter-by-letter reading strategy. Such a strategy should make it more difficult to infer the sound of digraphs. Our main aim was to disentangle length and digraph-presence effects in word and pseudoword reading. In addition,
Musculoskeletal pain and posture decrease step length in young adults
Directory of Open Access Journals (Sweden)
Maria Regina Rachmawati
2009-08-01
Full Text Available Pain of the musculoskeletal system, especially low back pain, is one of the most frequent problems with a high risk of disability. The aim of this research study was to determine the existence of an association between low back pain on one hand, posture and step length on the other. This cross-sectional study was conducted on 77 healthy young adult subjects. Step length was measured with the Biodex Gait Trainer 2 (230 VAC. The study results indicate that 62.3% of the young adult subjects had suffered from low back pain. There was no significant association between gender and pain. In male subjects no significant association was found between pain on one hand and mean difference in step length and posture on the other. However, in female subjects with abnormal posture, there was a highly significant difference in left step length between subjects with back pain and those without (p=0.007. The results of a multiple regression analysis indicate that posture has the greatest influence on left step length (B=4.135; 95% Confidence Interval 0.292-7.977. It is recommended that in the examination of low back pain an assessment be made of posture, step length and difference in step lengths.
Musculoskeletal pain and posture decrease step length in young adults
Directory of Open Access Journals (Sweden)
Maria Regina Rachmawati
2016-02-01
Full Text Available Pain of the musculoskeletal system, especially low back pain, is one of the most frequent problems with a high risk of disability. The aim of this research study was to determine the existence of an association between low back pain on one hand, posture and step length on the other. This cross-sectional study was conducted on 77 healthy young adult subjects. Step length was measured with the Biodex Gait Trainer 2 (230 VAC. The study results indicate that 62.3% of the young adult subjects had suffered from low back pain. There was no significant association between gender and pain. In male subjects no significant association was found between pain on one hand and mean difference in step length and posture on the other. However, in female subjects with abnormal posture, there was a highly significant difference in left step length between subjects with back pain and those without (p=0.007. The results of a multiple regression analysis indicate that posture has the greatest influence on left step length (B=4.135; 95% Confidence Interval 0.292-7.977. It is recommended that in the examination of low back pain an assessment be made of posture, step length and difference in step lengths.
Information content versus word length in random typing
International Nuclear Information System (INIS)
Ferrer-i-Cancho, Ramon; Moscoso del Prado Martín, Fermín
2011-01-01
Recently, it has been claimed that a linear relationship between a measure of information content and word length is expected from word length optimization and it has been shown that this linearity is supported by a strong correlation between information content and word length in many languages (Piantadosi et al 2011 Proc. Nat. Acad. Sci. 108 3825). Here, we study in detail some connections between this measure and standard information theory. The relationship between the measure and word length is studied for the popular random typing process where a text is constructed by pressing keys at random from a keyboard containing letters and a space behaving as a word delimiter. Although this random process does not optimize word lengths according to information content, it exhibits a linear relationship between information content and word length. The exact slope and intercept are presented for three major variants of the random typing process. A strong correlation between information content and word length can simply arise from the units making a word (e.g., letters) and not necessarily from the interplay between a word and its context as proposed by Piantadosi and co-workers. In itself, the linear relation does not entail the results of any optimization process. (letter)
Evaluating Multispectral Snowpack Reflectivity With Changing Snow Correlation Lengths
Kang, Do Hyuk; Barros, Ana P.; Kim, Edward J.
2016-01-01
This study investigates the sensitivity of multispectral reflectivity to changing snow correlation lengths. Matzler's ice-lamellae radiative transfer model was implemented and tested to evaluate the reflectivity of snow correlation lengths at multiple frequencies from the ultraviolet (UV) to the microwave bands. The model reveals that, in the UV to infrared (IR) frequency range, the reflectivity and correlation length are inversely related, whereas reflectivity increases with snow correlation length in the microwave frequency range. The model further shows that the reflectivity behavior can be mainly attributed to scattering rather than absorption for shallow snowpacks. The largest scattering coefficients and reflectivity occur at very small correlation lengths (approximately 10(exp -5 m) for frequencies higher than the IR band. In the microwave range, the largest scattering coefficients are found at millimeter wavelengths. For validation purposes, the ice-lamella model is coupled with a multilayer snow physics model to characterize the reflectivity response of realistic snow hydrological processes. The evolution of the coupled model simulated reflectivities in both the visible and the microwave bands is consistent with satellite-based reflectivity observations in the same frequencies. The model results are also compared with colocated in situ snow correlation length measurements (Cold Land Processes Field Experiment 2002-2003). The analysis and evaluation of model results indicate that the coupled multifrequency radiative transfer and snow hydrology modeling system can be used as a forward operator in a data-assimilation framework to predict the status of snow physical properties, including snow correlation length.
Evaluation of Efficient Line Lengths for Better Readability
Directory of Open Access Journals (Sweden)
Zahid Hussain
2012-01-01
Full Text Available In this paper the major findings of a formal experiment about onscreen text line lengths are presented. The experiment examined the effects of four different line lengths on the reading speed and the reading efficiency. Efficiency is defined as a combination of reading speed and accuracy. Sixteen people between the age of 24 and 36 participated at the experiment. The subjects had to read four different texts with an average line length around 2000 characters. The texts contained substitution words, which had to be detected by the subjects to measure reading accuracy. Besides objective measures like reading speed and accuracy, the subjects were asked to subjectively vote on their reading experience. The results from our objective measures show strong similarities to those of the work done previously by different researchers. The absolute reading speed grows when the line length grows from CPL (Characters Per Line 30-120. The measured reading efficiency, however, doesn\\\\\\'t grow steadily, although a growing trend can be seen. This is due to the fact, that the test persons found in average more substitution words from the 60 CPL text than they did from the 30 and 90 CPL texts. The reading speed seems to increase while the line length increases but the overall comprehension seems to peak at medium line lengths. As in the previous studies, our test persons also prefer the medium (60 and 90 CPL line lengths, although they perform better when reading longer lines. In the overall subjective opinion 13 out of 16 test persons selected the 60 or 90 CPL line length as their favorite. The literature doesn\\\\\\'t truly provide a scientific explanation for the difference between the objective performance and the subjective preference. A natural hypothesis would be that the line length that is the fastest to read would also feel most comfortable to the readers but in the light of this and the earlier research it seems like this is not the case.
Does neighborhood size really cause the word length effect?
Guitard, Dominic; Saint-Aubin, Jean; Tehan, Gerald; Tolan, Anne
2018-02-01
In short-term serial recall, it is well-known that short words are remembered better than long words. This word length effect has been the cornerstone of the working memory model and a benchmark effect that all models of immediate memory should account for. Currently, there is no consensus as to what determines the word length effect. Jalbert and colleagues (Jalbert, Neath, Bireta, & Surprenant, 2011a; Jalbert, Neath, & Surprenant, 2011b) suggested that neighborhood size is one causal factor. In six experiments we systematically examined their suggestion. In Experiment 1, with an immediate serial recall task, multiple word lengths, and a large pool of words controlled for neighborhood size, the typical word length effect was present. In Experiments 2 and 3, with an order reconstruction task and words with either many or few neighbors, we observed the typical word length effect. In Experiment 4 we tested the hypothesis that the previous abolition of the word length effect when neighborhood size was controlled was due to a confounded factor: frequency of orthographic structure. As predicted, we reversed the word length effect when using short words with less frequent orthographic structures than the long words, as was done in both of Jalbert et al.'s studies. In Experiments 5 and 6, we again observed the typical word length effect, even if we controlled for neighborhood size and frequency of orthographic structure. Overall, the results were not consistent with the predictions of Jalbert et al. and clearly showed a large and reliable word length effect after controlling for neighborhood size.
Dorsal Phalloplasty to Preserve Penis Length after Penile Prosthesis Implantation
Directory of Open Access Journals (Sweden)
Osama Shaeer
2017-03-01
Full Text Available Objectives: Following penile prosthesis implantation (PPI, patients may complain of a decrease in visible penis length. A dorsal phalloplasty defines the penopubic junction by tacking pubic skin to the pubis, revealing the base of the penis. This study aimed to evaluate the efficacy of a dorsal phalloplasty in increasing the visible penis length following PPI. Methods: An inflatable penile prosthesis was implanted in 13 patients with severe erectile dysfunction (ED at the Kamal Shaeer Hospital, Cairo, Egypt, from January 2013 to May 2014. During the surgery, nonabsorbable tacking sutures were used to pin the pubic skin to the pubis through the same penoscrotal incision. Intraoperative penis length was measured before and after the dorsal phalloplasty. Overall patient satisfaction was measured on a 5-point rating scale and patients were requested to subjectively compare their postoperative penis length with memories of their penis length before the onset of ED. Results: Intraoperatively, the dorsal phalloplasty increased the visible length of the erect penis by an average of 25.6%. The average length before and after tacking was 10.2 ± 2.9 cm and 13.7 ± 2.8 cm, respectively (P <0.002. Postoperatively, seven patients (53.8% reported a longer penis, five patients (38.5% reported no change in length and one patient (7.7% reported a slightly shorter penis. The mean overall patient satisfaction score was 4.9 ± 0.3. None of the patients developed postoperative complications. Conclusion: A dorsal phalloplasty during PPI is an effective method of increasing visible penis length, therefore minimising the impression of a shorter penis after implantation.
Focal Length Affects Depicted Shape and Perception of Facial Images.
Directory of Open Access Journals (Sweden)
Vít Třebický
Full Text Available Static photographs are currently the most often employed stimuli in research on social perception. The method of photograph acquisition might affect the depicted subject's facial appearance and thus also the impression of such stimuli. An important factor influencing the resulting photograph is focal length, as different focal lengths produce various levels of image distortion. Here we tested whether different focal lengths (50, 85, 105 mm affect depicted shape and perception of female and male faces. We collected three portrait photographs of 45 (22 females, 23 males participants under standardized conditions and camera setting varying only in the focal length. Subsequently, the three photographs from each individual were shown on screen in a randomized order using a 3-alternative forced-choice paradigm. The images were judged for attractiveness, dominance, and femininity/masculinity by 369 raters (193 females, 176 males. Facial width-to-height ratio (fWHR was measured from each photograph and overall facial shape was analysed employing geometric morphometric methods (GMM. Our results showed that photographs taken with 50 mm focal length were rated as significantly less feminine/masculine, attractive, and dominant compared to the images taken with longer focal lengths. Further, shorter focal lengths produced faces with smaller fWHR. Subsequent GMM revealed focal length significantly affected overall facial shape of the photographed subjects. Thus methodology of photograph acquisition, focal length in this case, can significantly affect results of studies using photographic stimuli perhaps due to different levels of perspective distortion that influence shapes and proportions of morphological traits.
Length Contraction Should not be Independent of Time
Smarandache, Florentin
2013-10-01
In Special Theory of Relativity it looks that the length contraction along the direction of the motion is independent of time, i.e. if a rocket flies one second, or the rocket flies one year the rocket's along-the-motion length contraction is the same, since the contraction factor C (v) =√{ 1 -v2/c2 } depends on the rocket's relativistic speed (v) and on the light speed in vacuum (c) only. We find this as unrealistic, incomplete. It is logical that flying more and more it should increase the length contraction. What about the cosmic bodies that continuously travel, do they contract only once or are they continuously contracting?
Modes in a nonneutral plasma column of finite length
International Nuclear Information System (INIS)
Rasband, S. Neil; Spencer, Ross L.
2002-01-01
A Galerkin, finite-element, nonuniform mesh computation of the mode equation for waves in a non-neutral plasma of finite length in a Cold-Fluid model gives an accurate calculation of the mode eigenfrequencies and eigenfunctions. We report on studies of the following: (1) finite-length Trivelpiece-Gould modes with flat-top and realistic density profiles, (2) finite-length diocotron modes with flat density profiles. We compare with the frequency equation of Fine and Driscoll [Phys Plasmas 5, 601 (1998)
Exploiting Universality in Atoms with Large Scattering Lengths
International Nuclear Information System (INIS)
Braaten, Eric
2012-01-01
The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.
Local-field refinement of neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Sears, V F
1985-06-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed.
Local-field refinement of neutron scattering lengths
International Nuclear Information System (INIS)
Sears, V.F.
1985-01-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed. (orig.)
Minimal Length Effects on Tunnelling from Spherically Symmetric Black Holes
Directory of Open Access Journals (Sweden)
Benrong Mu
2015-01-01
Full Text Available We investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole’s mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
Electron Bunch Length Diagnostic With Coherent Smith-Purcell Radiation
Energy Technology Data Exchange (ETDEWEB)
Nguyen, D.C.
1997-05-12
The authors have designed a new technique for measuring subpicosecond electron bunch lengths using coherent Smith-Purcell radiation. This new diagnostic technique involves passing the electron beam in close proximity of a grating with a period comparable to the electron bunch length. The emitted Smith-Purcell radiation will have a coherent component whose angular position and distribution are directly related to the electron bunch length and longitudinal profile, respectively. This new diagnostic technique is inherently simple, inexpensive and non-intercepting. The authors show that the new technique is also scaleable to femtosecond regime.
Hydrogen atom in momentum space with a minimal length
International Nuclear Information System (INIS)
Bouaziz, Djamil; Ferkous, Nourredine
2010-01-01
A momentum representation treatment of the hydrogen atom problem with a generalized uncertainty relation, which leads to a minimal length ΔX imin =(ℎ/2π)√(3β+β ' ), is presented. We show that the distance squared operator can be factorized in the case β ' =2β. We analytically solve the s-wave bound-state equation. The leading correction to the energy spectrum caused by the minimal length depends on √(β). An upper bound for the minimal length is found to be about 10 -9 fm.
Electron Bunch Length Diagnostic With Coherent Smith-Purcell Radiation
International Nuclear Information System (INIS)
Nguyen, D.C.
1997-01-01
The authors have designed a new technique for measuring subpicosecond electron bunch lengths using coherent Smith-Purcell radiation. This new diagnostic technique involves passing the electron beam in close proximity of a grating with a period comparable to the electron bunch length. The emitted Smith-Purcell radiation will have a coherent component whose angular position and distribution are directly related to the electron bunch length and longitudinal profile, respectively. This new diagnostic technique is inherently simple, inexpensive and non-intercepting. The authors show that the new technique is also scaleable to femtosecond regime
Mesoscopic Length Scale Controls the Rheology of Dense Suspensions
Bonnoit, Claire; Lanuza, Jose; Lindner, Anke; Clement, Eric
2010-09-01
From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, we evidence a nonlocal effective viscosity, decreasing as a power law of the flow height. We establish a scaling relation between this mesoscopic length scale and the suspension viscosity. These results support recent theoretical and numerical results implying collective and clustered granular motion when the jamming point is approached from below.
An Assessment of the Length and Variability of Mercury's Magnetotail
Milan, S. E.; Slavin, J. A.
2011-01-01
We employ Mariner 10 measurements of the interplanetary magnetic field in the vicinity of Mercury to estimate the rate of magnetic reconnection between the interplanetary magnetic field and the Hermean magnetosphere. We derive a time-series of the open magnetic flux in Mercury's magnetosphere. from which we can deduce the length of the magnetotail The length of the magnetotail is shown to be highly variable. with open field lines stretching between 15R(sub H) and 8S0R(sub H) downstream of the planet (median 150R(sub H)). Scaling laws allow the tail length at perihelion to be deduced from the aphelion Mariner 10 observations.
Cervical length at 23 weeks' gestation - relation to demographic ...
African Journals Online (AJOL)
significance of differences in median cervical lengths between subgroups was calculated according to maternal age, ethnic origin, maternal body mass ... and mortality worldwide, with major health care and economic consequences.u In South ...
The compound microscope: optical tube length or parfocalization?
International Nuclear Information System (INIS)
Simon, J M; Comastri, S A
2005-01-01
In various well-known textbooks for undergraduate students of physics, the compound microscope is described as having a standardized 'optical tube length'. On the other hand, in order to fulfil the parfocalization condition required by the human visual system to understand the relation between what is viewed with and without the microscope, the distance between the object and its image through the objective must remain constant as objectives are interchanged. In this paper, we show that these two requirements are not compatible in microscopes containing a revolver with various objectives and that the 'optical tube length' (which differs from the mechanical tube length) cannot be standardized. Moreover, we consider the Deutsche Industrie Norm (DIN) and the Japanese Industry Standards (JIS) norms employed in the microscope industry for standardization of the object-to-intermediate image distance, the parfocal distance and the mechanical tube length
Length scale of secondary stresses in fracture and fatigue
International Nuclear Information System (INIS)
Dong, P.
2008-01-01
In an attempt to provide a consistent framework for the analysis and treatment of secondary stresses associated with welding and thermal loading in the context of fracture mechanics, this paper starts with an effective stress characterization procedure by introducing a length-scale concept. With it, a traction-based stress separation procedure is then presented to provide a consistent characterization of stresses from various sources based on their length scale. Their relative contributions to fracture driving force are then quantified in terms of their characteristic length scales. Special attention is given to the implications of the length-scale argument on both analysis and treatment of welding residual stresses in fracture assessment. A series of examples is provided to demonstrate how the present developments can be applied for treating not only secondary stresses but also externally applied stresses, as well as their combined effects on the structural integrity of engineering components
Interplay between multiple length and time scales in complex ...
Indian Academy of Sciences (India)
Administrator
Processes in complex chemical systems, such as macromolecules, electrolytes, interfaces, ... by processes operating on a multiplicity of length .... real time. The design and interpretation of femto- second experiments has required considerable ...
From Concrete to Abstract in the Measurement of Length
International Nuclear Information System (INIS)
Stephanou, Andreas; Fisher, William P Jr
2013-01-01
The concatenation of units of length is widely viewed as the paradigmatic expression of fundamental measurement. Survey, assessment, and test scores in educational and psychological measurement are often interpreted in ways that assume a concatenation of units to have been established, even though these assumptions are rarely stated or tested. A concatenation model for measurement is shown to be equivalent to a Rasch model: any two units of measurement placed end to end must together be of the same length as either one of them added to itself. This additive principle and a concatenation model of measurement together serve as a heuristic guide for organizing two experimental approaches to calibrating instruments for measuring length. The capacity to reproduce the unit of measurement from theory with no need for repeated empirical calibration experiments, as in the geometrical bisection of the line and the resultant halving of the length measure, is highlighted as essential to demonstrating a thorough understanding of the construct
Naloxone fails to prolong seizure length in ECT.
Rasmussen, K G; Pandurangi, A K
1999-12-01
Electroconvulsive shock (ECS) in animals has been shown to enhance endogenous opiate systems. The anticonvulsant effects of ECS are also partially blocked by the opiate receptor antagonist naloxone, leading some investigators to postulate that the anticonvulsant effects of ECS are mediated by activation of endogenous opiates. If such a phenomenon occurs in humans, then naloxone might prolong seizure length in electroconvulsive therapy (ECT). In the present study, nine patients were given 2.0 mg intravenous (i.v.) naloxone 2 minutes prior to one-half of their ECT treatments. Motor seizure length was measured via the cuff technique. EEG tracings were read by an investigator blind to naloxone status. There was no difference between the two groups in either EEG or nonblindly evaluated motor seizure length. It is concluded that a dose of 2 mg naloxone does not effectively increase seizure length in ECT.
Discrepancies in reporting the CAG repeat lengths for Huntington's disease
DEFF Research Database (Denmark)
Quarrell, Oliver W; Handley, Olivia; O'Donovan, Kirsty
2011-01-01
Huntington's disease results from a CAG repeat expansion within the Huntingtin gene; this is measured routinely in diagnostic laboratories. The European Huntington's Disease Network REGISTRY project centrally measures CAG repeat lengths on fresh samples; these were compared with the original...
Ultrasonographic assessment of renal length in 310 Turkish children ...
African Journals Online (AJOL)
Ultrasonography is a non-invasive modality that can be used to measure RL.[2] ... cases were selected for inclusion in the study. Ultrasonography was ... Linear regression equations for predicting a variable (renal length) from independent ...
Relationships between length and coverage of decision rules
Amin, Talha M.; Chikalov, Igor; Moshkov, Mikhail; Zielosko, Beata
2014-01-01
The paper describes a new tool for study relationships between length and coverage of exact decision rules. This tool is based on dynamic programming approach. We also present results of experiments with decision tables from UCI Machine Learning Repository.
Relationships between length and coverage of decision rules
Amin, Talha
2014-02-14
The paper describes a new tool for study relationships between length and coverage of exact decision rules. This tool is based on dynamic programming approach. We also present results of experiments with decision tables from UCI Machine Learning Repository.
The Distribution of Lightning Channel Lengths in Northern Alabama Thunderstorms
Peterson, H. S.; Koshak, W. J.
2010-01-01
Lightning is well known to be a major source of tropospheric NOx, and in most cases is the dominant natural source (Huntreiser et al 1998, Jourdain and Hauglustaine 2001). Production of NOx by a segment of a lightning channel is a function of channel segment energy density and channel segment altitude. A first estimate of NOx production by a lightning flash can be found by multiplying production per segment [typically 104 J/m; Hill (1979)] by the total length of the flash s channel. The purpose of this study is to determine average channel length for lightning flashes near NALMA in 2008, and to compare average channel length of ground flashes to the average channel length of cloud flashes.
The length of the glaciers in the world
DEFF Research Database (Denmark)
Machguth, Horst; Huss, M.; Huss, M.
2014-01-01
a fully automated method based on glacier surface slope, distance to the glacier margins and a set of trade-off functions. The method is developed for East Greenland, evaluated for the same area as well as for Alaska, and eventually applied to all ∼ 200000 glaciers around the globe. The evaluation...... highlights accurately calculated glacier length where DEM quality is good (East 10 Greenland) and limited precision on low quality DEMs (parts of Alaska). Measured length of very small glaciers is subject to a certain level of ambiguity. The global calculation shows that only about 1.5% of all glaciers...... are longer than 10km with Bering Glacier (Alaska/Canada) being the longest glacier in the world at a length of 196 km. Based on model output we derive global and regional area-length scaling laws. Differences among regional scaling parameters appear to be related to characteristics of topography and glacier...
Finite length thermal equilibria of a pure electron plasma column
International Nuclear Information System (INIS)
Prasad, S.A.; O'Neil, T.M.
1979-01-01
The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length
Minimal length uncertainty and generalized non-commutative geometry
International Nuclear Information System (INIS)
Farmany, A.; Abbasi, S.; Darvishi, M.T.; Khani, F.; Naghipour, A.
2009-01-01
A generalized formulation of non-commutative geometry for the Bargmann-Fock space of quantum field theory is presented. The analysis is related to the symmetry of the simplistic space and a minimal length uncertainty.
Isospin breaking in the pion-nucleon scattering lengths
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2009-01-01
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Isospin breaking in the pion-nucleon scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2009-07-06
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Dependence of paracentric inversion rate on tract length
DEFF Research Database (Denmark)
York, Thomas L; Durrett, Rick; Nielsen, Rasmus
2007-01-01
BACKGROUND: We develop a Bayesian method based on MCMC for estimating the relative rates of pericentric and paracentric inversions from marker data from two species. The method also allows estimation of the distribution of inversion tract lengths. RESULTS: We apply the method to data from...... Drosophila melanogaster and D. yakuba. We find that pericentric inversions occur at a much lower rate compared to paracentric inversions. The average paracentric inversion tract length is approx. 4.8 Mb with small inversions being more frequent than large inversions.If the two breakpoints defining...... a paracentric inversion tract are uniformly and independently distributed over chromosome arms there will be more short tract-length inversions than long; we find an even greater preponderance of short tract lengths than this would predict. Thus there appears to be a correlation between the positions...
The screening length of interatomic potential in atomic collisions
International Nuclear Information System (INIS)
Yamamura, Y.; Takeuchi, W.; Kawamura, T.
1998-03-01
In computer studies on the interaction of charged particle with solids, many authors treat the nuclear collision by the Thomas-Fermi screened Coulomb potential. For better agreement with experiment, the screening length is modified sometimes. We investigate the theoretical background for the correction factor of the screening length in the interatomic potential which can be deduced from two steps. The first step is to select the correction factor of an isolated atom so as to match the average radius of the Thomas-Fermi electron distribution with that of the Hartree-Fock electron distribution, where we use the Clementi and Roetti's table. The second step is to determine the correction factor of the screening length of the interatomic potential by using a combination rule. The correction factors obtained for the screening length are in good agreement with those determined by the computer analysis of the Impact Collision Ion Scattering Spectroscopy (ICISS) data. (author)
Length-weight relationship of Giant Oyster, Crassostrea gyphoides (Schlotheim)
Digital Repository Service at National Institute of Oceanography (India)
Chatterji, A.; Ansari, Z.A.; Ingole, B.S.; Parulekar, A.H.
Relationship between shell length and total weight, shell weight and meat weight of giant oyster, Crassostrea gryphoides revealed that the growth of these parameters is very fast and significant. It indicates the suitability of the species concerned...
Spin-Charge Separation in Finite Length Metallic Carbon Nanotubes
Zhang, Yongyou; Zhang, Qingyun; Schwingenschlö gl, Udo
2017-01-01
Using time-dependent density functional theory, we study the optical excitations in finite length carbon nanotubes. Evidence of spin-charge separation is given in the spacetime domain. We demonstrate that the charge density wave is due to collective
Predicting the Liquid Lengths of Heavy Hydrogen Fuels
National Research Council Canada - National Science Library
Hoogterp, Laura L
2003-01-01
.... Using models formulated by previous researchers as well as the thermodynamic properties for three fuel surrogates the liquid length can be determined for diesel fuel, JP8 as well as provide a model...
Reasonable designing method for fillet welding leg length
Energy Technology Data Exchange (ETDEWEB)
Kiso, T; Michiyuki, T; Nagao, S; Yoshikawa, M; Miyazaki, S
1976-12-01
In VLCC and ULCC vessels, the scantling of structural members, especially the thickness of web plate, increases naturally. The present rule of each classification society generally prescribes that welding leg length should be based on the thickness of the web plate. Welding leg length between this web plate and skin plate such as shell plate, deck plate, etc., or face plate, increases according to increase of the thickness of the web plate. We investigated the method to decide reasonable welding leg length and its programming by using the results of finite element method structural analysis, without adhering to the above rule about welding leg length. As a result of applying this method to actual ships under classification societies' approval, the amount of welding decreased by from about 10 percent to 15 percent compared with that required by the above rule. The rationality of the method has been already confirmed by successful results of the application to several vessels in service.
Understanding the length dependence of molecular junction thermopower
DEFF Research Database (Denmark)
Karlström, Sven Olov Harald; Strange, Mikkel; Solomon, Gemma
2014-01-01
Thermopower of molecular junctions is sensitive to details in the junction and may increase, decrease, or saturate with increasing chain length, depending on the system. Using McConnell's theory for exponentially suppressed transport together with a simple and easily interpretable tight binding...... model, we show how these different behaviors depend on the molecular backbone and its binding to the contacts. We distinguish between resonances from binding groups or undercoordinated electrode atoms, and those from the periodic backbone. It is demonstrated that while the former gives a length......-independent contribution to the thermopower, possibly changing its sign, the latter determines its length dependence. This means that the question of which orbitals from the periodic chain that dominate the transport should not be inferred from the sign of the thermopower but from its length dependence. We find...
Telomere Length – a New Biomarker in Medicine
Directory of Open Access Journals (Sweden)
Agnieszka Kozłowska
2015-12-01
Full Text Available A number of xenobiotics in the environment and workplace influences on our health and life. Biomarkers are tools for measuring such exposures and their effects in the organism. Nowadays, telomere length, epigenetic changes, mutations and changes in gene expression pattern have become new molecular biomarkers. Telomeres play the role of molecular clock, which influences on expectancy of cell life and thus aging, the formation of damages, development diseases and carcinogenesis. The telomere length depends on mechanisms of replication and the activity of telomerase. Telomere length is currently used as a biomarker of susceptibility and/or exposure. This paper describes the role of telomere length as a biomarker of aging cells, oxidative stress, a marker of many diseases including cancer, and as a marker of environmental and occupational exposure.
Telomere length in normal and neoplastic canine tissues.
Cadile, Casey D; Kitchell, Barbara E; Newman, Rebecca G; Biller, Barbara J; Hetler, Elizabeth R
2007-12-01
To determine the mean telomere restriction fragment (TRF) length in normal and neoplastic canine tissues. 57 solid-tissue tumor specimens collected from client-owned dogs, 40 samples of normal tissue collected from 12 clinically normal dogs, and blood samples collected from 4 healthy blood donor dogs. Tumor specimens were collected from client-owned dogs during diagnostic or therapeutic procedures at the University of Illinois Veterinary Medical Teaching Hospital, whereas 40 normal tissue samples were collected from 12 control dogs. Telomere restriction fragment length was determined by use of an assay kit. A histologic diagnosis was provided for each tumor by personnel at the Veterinary Diagnostic Laboratory at the University of Illinois. Mean of the mean TRF length for 44 normal samples was 19.0 kilobases (kb; range, 15.4 to 21.4 kb), and the mean of the mean TRF length for 57 malignant tumors was 19.0 kb (range, 12.9 to 23.5 kb). Although the mean of the mean TRF length for tumors and normal tissues was identical, tumor samples had more variability in TRF length. Telomerase, which represents the main mechanism by which cancer cells achieve immortality, is an attractive therapeutic target. The ability to measure telomere length is crucial to monitoring the efficacy of telomerase inhibition. In contrast to many other mammalian species, the length of canine telomeres and the rate of telomeric DNA loss are similar to those reported in humans, making dogs a compelling choice for use in the study of human anti-telomerase strategies.
To the problem of the coherence length of neutrons
International Nuclear Information System (INIS)
Varga, P.
1992-11-01
The challenge of the high accuracy of certain optical measurements, the long coherence length of light provokes one to search for possibilities to enlarge the neutron coherence length. A proposal is made to achieve this by using a five or a four plate Bonse-Hart interferometer. A further problem is, whether the neutron beam is composed of wave packets or of overlapping independent monochromatic waves; it is considered that the former is more likely. (author) 12 refs.; 3 figs
The Length of Maternity Leave and Family Health
Beuchert, Louise Voldby; Humlum, Maria Knoth; Vejlin, Rune Majlund
2014-01-01
We study the relationship between the length of maternity leave and the physical and psychological health of the family. Using a reform of the parental leave scheme in Denmark that increased the number of weeks of leave with full benefit compensation,we estimate the effect of the length of maternity leave on a range of health indicators including the number of hospital admissions for both mother and child and the probability of the mother receiving antidepressants. The reform led to an increa...
Synthesis of aerogel tiles with high light scattering length
Danilyuk, A F; Okunev, A G; Onuchin, A P; Shaurman, S A
1999-01-01
The possibility of aerogel tiles production for RICH detectors is described. Monolithic blocks of silica aerogel were synthesized by two-step sol-gel processing of tetraethoxysilane Si(OEt) sub 4 followed by high temperature supercritical drying with organic solvent. The important characteristic of aerogel is the light scattering length. In the wide range of refraction indexes the light scattering length exceeds 4 cm at 400 nm.
Treatment options for tank farms long-length contaminated equipment
International Nuclear Information System (INIS)
Josephson, W.S.
1995-01-01
This study evaluated a variety of treatment and disposal technologies for mixed waste (MW) meeting the following criteria: 1. Single-Shell and Double-Shell Tank System (tank farms) equipment and other debris; 2. length greater than 12 feet; and contaminated with listed MW from the tank farms. This waste stream, commonly referred to as tank farms long-length contaminated equipment (LLCE), poses a unique and costly set of challenges during all phases of the waste management lifecycle
Determinants for Labour Contract Length: A French Microeconometric Study
Ben Halima, Mohamed; Ben Halima, Bassem
2008-01-01
International audience; Two types of analyses are conducted to explain the determinants of labour contracts length. The first analysis emphasizes on the contracting costs and the level of uncertainty. The second analysis focuses on the incentive and selection effect of the contract length. This paper test the determinants for contract duration by means of econometric duration models. The estimates are carried out from French data (TDE). An econometric treatment of the endogeneity of the labou...
In vivo myograph measurement of muscle contraction at optimal length
Directory of Open Access Journals (Sweden)
Ahmed Aminul
2007-01-01
Full Text Available Abstract Background Current devices for measuring muscle contraction in vivo have limited accuracy in establishing and re-establishing the optimum muscle length. They are variable in the reproducibility to determine the muscle contraction at this length, and often do not maintain precise conditions during the examination. Consequently, for clinical testing only semi-quantitative methods have been used. Methods We present a newly developed myograph, an accurate measuring device for muscle contraction, consisting of three elements. Firstly, an element for adjusting the axle of the device and the physiological axis of muscle contraction; secondly, an element to accurately position and reposition the extremity of the muscle; and thirdly, an element for the progressive pre-stretching and isometric locking of the target muscle. Thus it is possible to examine individual in vivo muscles in every pre-stretched, specified position, to maintain constant muscle-length conditions, and to accurately re-establish the conditions of the measurement process at later sessions. Results In a sequence of experiments the force of contraction of the muscle at differing stretching lengths were recorded and the forces determined. The optimum muscle length for maximal force of contraction was established. In a following sequence of experiments with smaller graduations around this optimal stretching length an increasingly accurate optimum muscle length for maximal force of contraction was determined. This optimum length was also accurately re-established at later sessions. Conclusion We have introduced a new technical solution for valid, reproducible in vivo force measurements on every possible point of the stretching curve. Thus it should be possible to study the muscle contraction in vivo to the same level of accuracy as is achieved in tests with in vitro organ preparations.